Management in the new normal is an inventiveness to adopt new drift in the education system. Thus, this research study purposely to examine the Management and Challenges of Criminology Deans in this progression of new normal living condition. A qualitative research approach particularly a Case Study design was utilized. The population of this study were focused on the Seven (7) Deans of Criminal Justice Education of various Universities and Colleges and a Semi Structured Interview employing the open ended questions was (...) utilized in order to extract more discussion on the Management and Challenges of the different deans, guided by the ethical principles on research. The results found out two challenges in the new normal; the Flexible and Remote Learning and Blended Learning Modalities. Intervention approach was also identified like the Work Home Status, Asynchronous and Synchronous Study Learning and Social Media plat forms. Indeed, the management of Deans is immediately needed in this challenging time like; lack of new computer skills, Academic freedom of teachers regarding poor performances of students, the duties and responsibilities of the personnel towards clienteles. (shrink)

The concept of metaphor as primarily a vehicle for conveying ideas, even if unusual ones, seems to me as wrong as the parent idea that a metaphor has a special meaning. I agree with the view that metaphors cannot be paraphrased, but I think this is not because metaphors say something too novel for literal expression but because there is nothing there to paraphrase. Paraphrase, whether possible or not, inappropriate to what is said: we try, in paraphrase, to say it (...) another way. But if I am right, a metaphor doesn't say anything beyond its literal meaning. This is not, of course, to deny that a metaphor has a point, nor that that point can be brought out by using further words.... My disagreement is with the explanation of how metaphor works its wonders. To anticipate: I depend on the distinction between what words mean and what they are used to do. I think metaphor belongs exclusively to the domain of use. It is something brought off by the imaginative employment of words and sentences and depends entirely on the ordinary meanings of those words and hence on the ordinary meanings of the sentences they comprise. Donald Davidson is University Professor of philosophy at the University of Chicago. He is the author of many important essays, including "Actions, Reasons and Causes," "Causal Relations," and "Truth and Meaning," coauthor of Decision-Making: An Experimental Approach, and coeditor of Words and Objections, Semantics of Natural Language, and The Logic of Grammar. (shrink)

According to the Weak Supplementation Principle (WSP)—a widely received principle of mereology—an object with a proper part, p , has another distinct proper part that doesn't overlap p . In a recent article in this journal, Nikk Effingham and Jon Robson employ WSP in an objection to endurantism. I defend endurantism in a way that bears on mereology in general. First, I argue that denying WSP can be motivated apart from the truth of endurantism. I then go on to offer (...) an explanation of WSP's initial appeal, argue that denying WSP fails to have untoward consequences for the rest of mereology, and show that the falsity of WSP is consistent with a primary guiding thought behind it. (shrink)

According to perdurantism, objects persist by being spread out over time, just as composite three-dimensional objects are spread out over space. Just as a composite three-dimensional object is spread out over space by having spatial parts, objects persist, according to perdurantism, by having temporal parts. Perdurantism can be stated more precisely by saying what exactly a temporal part is. In the sequel, Theodore Sider's definition of "instantaneous temporal part" shall be assumed: x is an instantaneous temporal part of y at (...) instant t =df. x exists at, but only at, t; x is part of y at t; and x overlaps at t everything that is part of y at t. Much more could be and has been said about how perdurantism should be formulated. Though interesting in their own right, nothing of importance here turns on these matters of formulation. (shrink)

Philosophical conceptual analysis is an experimental method. Focusing on this helps to justify it from the skepticism of experimental philosophers who follow Weinberg, Nichols & Stich. To explore the experimental aspect of philosophical conceptual analysis, I consider a simpler instance of the same activity: everyday linguistic interpretation. I argue that this, too, is experimental in nature. And in both conceptual analysis and linguistic interpretation, the intuitions considered problematic by experimental philosophers are necessary but epistemically irrelevant. They are like variables introduced (...) into mathematical proofs which drop out before the solution. Or better, they are like the hypotheses that drive science, which do not themselves need to be true. In other words, it does not matter whether or not intuitions are accurate as descriptions of the natural kinds that undergird philosophical concepts; the aims of conceptual analysis can still be met. (shrink)

A popular positivistic line of thinking seems to be cropping up again, declaring that the sciences are on the verge of a paradigmatic shift. One that will merge science and philosophy to finally answer all the great big questions once and for all. Questions such as What is life? What is consciousness? What makes individuals who they are? Why does our universe seem fine-tuned for our existence? How did it all begin? While such questions are undoubtedly important, the truth is, (...) they are essentially philosophical. That is to say, they escape the kind of exactness required of the hard sciences. The upshot is that they are at best only answerable to a limited extent, if they are even answerable at all. (shrink)

Bjorn T. Ramberg’s book focuses on Davidson’s work in the philosophy of language, published between 1984 and the appearance of the book. Recent papers provide the focus for an overview of Davidson’s philosophy of language and its relations to broader debates and influences. Still, the reader is warned: the author “cannot claim” that the book “is in every detail a faithful representation or development of Davidson’s own current theory.” Instead, what we have is a “reconstruction” of Davidson on language and (...) meaning, an account “Davidsonian in spirit and in all its fundamental features.”1 The result is a projection of Davidson’s views, or important aspects of them, in a particular direction: Davidson and in- terpretation in process. The following critical discussion of main issues in Ramberg’s book should not dis- tract potential readers from this useful and thoughtful overview of Davidson on interpretation and meaning. (shrink)

In 2010, pitcher Armando Galarraga was denied a perfect game when umpire Jim Joyce called Jason Donald safe at first with two outs in the bottom of the 9th. In the numerous media discussions that followed, Joyce’s ‘blown’ call was commonly referred to as ‘mistaken’, ‘wrong’, or otherwise erroneous. However, this use of language makes some not uncontroversial ontological assumptions. It claims that the fact that a runner is safe or out has nothing to do with the ruling of (...) the umpire himself, but rather with some state of the universe that does not depend on the umpire for its existence. In this paper, I recast the problem as a version of Plato’s Euthyphro Dilemma and argue that the view implied by the above assertions is actually misguided. Instead, I hope to show that an alternative view – what I call ‘restricted umpire voluntarism’ – is actually more in line with the spirit of the game of baseball and is not as counterintuitive as it may appear.. (shrink)

Donald T. Campbell outlines an epistemological theory that attempts to be faithful to evolution through natural selection. He takes his position to be consistent with that of Karl R. Popper, whom he credits as the primary advocate of his day for natural selection epistemology. Campbell writes that neither he nor Popper want to give up the goal of objectivity or objective truth, in spite of their evolutionary epistemology. In discussing the conflict between an epistemology based on natural selection and (...) objective truth, Campbell cites an article by the German sociologist and philosopher Georg Simmel entitled 'On a Connection of Selection Theory to Epistemology', as presenting the issue in a notably forthright manner.The present essay summarizes Simmel's article, with the purpose of clarifying, in terms that Campbell apparently finds satisfactory, the conflict that Campbell acknowledges between an evolutionary epistemology and ultimate truth; the essay then examines the responses of Campbell and Popper to Simmel's position. While Campbell and Popper acknowledge the work of Simmel, their responses suggest something less than a full consideration of Simmel's position. (shrink)

The article discusses the future of US democracy after the end of Donald J. Trump’s scandal-ridden presidency, which culminated in a violent attempted self-coup. In contrast to many observers outside the United States who appear to assume that Joe Biden’s inauguration marks the failure of the coup attempt, I argue that this view is overly optimistic. First, Trump by no means acted alone but was supported by leading figures in the Republican Party (GOP). Second, the attack on democratic norms (...) and institutions to restore and permanently cement Republican minority rule continues to move forward. The 2022 midterm elections and the 2024 presidential election set the course on whether the United States will return to liberal democracy or degrade into Hungary-style competitive authoritarianism. (shrink)

THE MIND-BODY PROBLEM: A GUIDE TO THE CURRENT DEBATE (EDITED BY RICHARD WARNER AND TA D E U S Z SZUBKA) contains recent essays by the key players in the the field of the Mind-Body problem: Searle, Fodor, Problem Honderich, Nagel, McGinn, Stich, Rorty and others. But there are a few interesting exceptions, for example Edelman, Popper, Putnam and Dennett. Nevertheless, these thinkers do get a mention here and there, and nearly all the exciting topical issues are dealt with, including (...) externalism, functionalism, intentionality, Turing computational models, and the relationship between these philosophical problems and psychology. I am particularly struck by the tendency to engage in an evasive stratagem when it comes to stating the physicalist thesis. Instead of a clear definitive position about what kind of physical science would achieve the hoped-for reduction, what I found was variations on Lewis's claim that the reduction would be effected by a "unified body of scientific theories of the sort we now accept". Materialism used to be a clear doctrine: a clockwork Universe of impenetrable particles. But materialism transcended itself. First through Hobbes' and Leibniz's criticisms of Descartes, then Newton's demolition of the Cartesian idea that matter was essentially extension by introducing gravity (action at a distance) and then through the field theories of Faraday and Maxwell, and more recently through Einstein's work, which undermined the "substance" view of matter, something that remained permanent while other changes occurred. I contrast the perspectives of the Churchlands with those of Donald T. Campbell, Karl Popper and other evolutionary and emergentist views. -/- . (shrink)

The wrong kind of reason (WKR) problem is a problem for attempts to analyze normative properties using only facts about the balance of normative reasons, a style of analysis on which the ‘Reasons First’ programme depends. I argue that this problem cannot be solved if the orthodox view of reasons is true --- that is, if each normative reason is numerically identical with some fact, proposition, or state-of-affairs. That’s because solving the WKR problem requires completely distinguishing between the right- and (...) wrong-kind reasons for an attitude. I argue that some facts give both right- and wrong-kind reasons for an attitude. Consequently, no such distinction between the two types of reasons is complete if reasons are facts or the like. I conclude by suggesting that reasons and facts are related by constitution, not identity. (shrink)

Although Donald Davidson is best known for his account of motivating reasons, towards the end of his life he did write about normative reasons, arguing for a novel form of realism we might call anomalous naturalism: anomalous, because it is not just non-reductive but also non-revisionary, refusing to compromise in any way on the thought that the prescriptive authority of normative reasons is objective and reaches to all possible agents; naturalism, because it still treats normative properties as perfectly ordinary (...) causal properties, and thus avoids many of the epistemological problems that bedevil realisms of the sort recently advanced by Thomas Nagel, Derek Parfit, and T. M. Scanlon. In the first section of the paper, I discuss Davidson’s understanding of objective prescriptivity and one important challenge that it faces. In the second section, I show how an answer to this challenge can be found in Davidson’s holism of the mental. As we shall see, Davidson’s holism of the mental makes the possibility of strongly prescriptive properties much easier to take seriously. In the final section of the paper, I take up various grounds for doubting that such properties could also be causal. (shrink)

The cognitive scientist Donald Hoffman argues that we don't perceive reality: spacetime, objects, colors, sounds, tastes, and so forth, are all merely an interface that we evolved to track evolutionary fitness rather than to perceive truths about external reality. In this paper, I expound on his argument, then I extend it, primarily, by looking at key ideas in physics that are quite germane to it. Among the topics in physics that I discuss are black holes, the holographic principle, string (...) theory, duality, quantum gravity, and special relativity. I discuss these ideas from physics with an eye to their relevance for Hoffman's view. (shrink)

Because factory-farmed meat production inflicts gratuitous suffering upon animals and wreaks havoc on the environment, there are morally compelling reasons to become vegetarian. Yet industrial plant agriculture causes the death of many field animals, and this leads some to question whether consumers ought to get some of their protein from certain kinds of non factory-farmed meat. Donald Bruckner, for instance, boldly argues that the harm principle implies an obligation to collect and consume roadkill and that strict vegetarianism is thus (...) immoral. But this argument works only if the following claims are true: all humans have access to roadkill, roadkill would go to waste if those who happen upon it don’t themselves consume it, it’s impossible to harvest vegetables without killing animals, the animals who are killed in plant production are all-things-considered harmed by crop farming, and the best arguments for vegetarianism all endorse the harm principle. As I will argue in this paper, each claim is deeply problematic. Consequently, in most cases, humans ought to strictly eat plants and save the roadkill for cats. (shrink)

This article frames Trump's politics through a genealogy of propaganda, going back to P.T. Barnum in the 19th century and moving through the crowd psychologist Gustave Le Bon and the public relations counsel Edward Bernays in the 20th. This genealogy shows how propaganda was developed as a tool by eager professionals who would hire themselves to the elite to control the masses. Trump’s propaganda presents a break in that he has not only removed professionals from control over his propaganda, he (...) has mobilized it as a force against them. His lower and middle class supporters may not materially gain from Trump’s politics, but they get to vent their ressentiment on the professional class and see them too become the targets of propagandistic control. Ultimately, the conflict between working class whites, those without college degrees, and professionals earns little for its participants and occludes the role that elites play in class dynamics in the United States. This article adds substance and context to the claims that Trump’s appeal is anti-professional while showing that the claims that his supporters are ‘voting against their interests’ does not reflect the real psychological benefits many Trumpists get from supporting him. (shrink)

The starting point of this paper concerns the apparent difference between what we might call absolute truth and truth in a model, following Donald Davidson. The notion of absolute truth is the one familiar from Tarski’s T-schema: ‘Snow is white’ is true if and only if snow is white. Instead of being a property of sentences as absolute truth appears to be, truth in a model, that is relative truth, is evaluated in terms of the relation between sentences and (...) models. I wish to examine the apparent dual nature of logical truth (without dwelling on Davidson), and suggest that we are dealing with a distinction between a metaphysical and a linguistic interpretation of truth. I take my cue from John Etchemendy, who suggests that absolute truth could be considered as being equivalent to truth in the ‘right model’, i.e., the model that corresponds with the world. However, the notion of ‘model’ is not entirely appropriate here as it is closely associated with relative truth. Instead, I propose that the metaphysical interpretation of truth may be illustrated in modal terms, by metaphysical modality in particular. One of the tasks that I will undertake in this paper is to develop this modal interpretation, partly building on my previous work on the metaphysical interpretation of the law of non-contradiction (Tahko 2009). After an explication of the metaphysical interpretation of logical truth, a brief study of how this interpretation connects with some recent important themes in philosophical logic follows. In particular, I discuss logical pluralism and propose an understanding of pluralism from the point of view of the metaphysical interpretation. (shrink)

Philosophers of mind typically conduct their discussions in terms of mental events, mental processes, mental properties, mental states – but rarely in terms of minds themselves. Sometimes this neglect is explicitly acknowledged. Donald Davidson, for example, writes that ‘there are no such things as minds, but people have mental properties, which is to say that certain psychological predicates are true of them. These properties are constantly changing, and such changes are mental events’.2 Hilary Putnam agrees, though for somewhat different (...) reasons: The view I have long defended is that the mind is not a thing; talk of our minds is talk of world-involving capabilities that we have and activities that we engage in. As Dewey succinctly put it, “Mind is primarily a verb. It denotes all the ways in which we deal consciously and expressly with the situation in which we find ourselves. Unfortunately, an influential manner of thinking has changed modes of action into an underlying substance that performs the activities in question. It has treated mind as an independent entity which attends, purposes, cares and remembers”. But the traditional view, by treating mental states as states of the “underlying substance”, makes them properties of something “inside”, and, if one is a materialist philosopher, that means properties of our brains. So the next problem naturally seems to be: “Which neurological properties of our brains do these mental properties ‘reduce’ to?” For how could our brains have properties that aren’t neurological? And this is how materialist philosophers saw the problem until the advent of such new alternatives in the philosophy of mind and philosophy of language as Functionalism and Semantic Externalism. (shrink)

Jeagwon Kim's exclusion argument is a well-known argument against non-reductive physicalism in the contemporary debate on mental causation. In this essay, we will first discuss two versions of the exclusion argument: the simple version and the sophisticated version. Secondly, we will take a conservative strategy to defend the kind of non-reductive physicalism initiated by Donald Davidson: the Token Identity Theory. Namely, we will explain where Kim failed to appropriately understand Davidson's work and argue that the simple version and the (...) sophisticated version of the exclusion argument won't work against the clarified token identity theory at all. Lastly, Since much of Kim's inappropriate interpretation of Davidson's work is rooted in their difference in metaphysics, there is reason to believe the proper understanding and evaluation on contemplation as such on mental causation, non-reductive physicalism, and other related problems can't be achieved without finding an appropriate metaphysical frame. (shrink)

We use quotation marks when we wish to refer to an expression. We can and do so refer even when this expression is composed of characters that do not occur in our alphabet. That's why Tarski, Quine, and Geach's theories of quotation don't work. The proposals of Davidson, Frege, and C. Washington, however, do not provide a plausible account of quotation either. (Section I). The problem is to construct a Tarskian theory of truth for an object language that contains quotation (...) marks, without appealing to quotation marks in the metalanguage. I propose to supply Tarski's truth definition with one axiom that determines the denotation of all expressions containing quotation marks. According to this axiom, quotation marks create a non-extensional context. Since admitting such contexts does not lead to any difficulties in the recursive truth characterization, we may indeed dispense with extensionalism. (Section II). Finally, I argue that we classify and denote expressions in the very same way that we classify and denote extralinguistic entities. Both tokens and types of written signs can be easily incorporated into the naturalist's worldview. (Section III). (shrink)

An attempt to defend Davidson's omniscient interpreter argument against various attempts to show that it does not succeed in showing that most of our beliefs must be true. It doesn't argue that this is a good answer to skepticism.

Imagine both that (1) S1 is deliberating at t about whether or not to x at t' and that (2) although S1’s x-ing at t' would not itself have good consequences, good consequences would ensue if both S1 x's at t' and S2 y's at t", where S1 may or may not be identical to S2 and where t < t' ≤ t". In this paper, I consider how consequentialists should treat S2 and the possibility that S2 will y at (...) t". At one end of the spectrum, consequentialists would hold that, in deciding whether or not to x at t', S1 should always treat S2 as a force of nature over which she has no control and, thus, treat the possibility that S2 will y at t" as she would the possibility that a hurricane will take a certain path. On this view, S1 is to predict whether or not S2 will y and act accordingly. At the other end of the spectrum, consequentialists would hold that S1 should always treat S2 as someone available for mutual cooperation and, thus, treat the possibility that S2 will y at t" as something to be relied upon. On this view, S1 is to rely on S2’s cooperation and so play her part in the best cooperative scheme involving the two of them. A third and intermediate position would be to hold that whether S1 should treat S2 as a force of nature or as someone available for mutual cooperation depends on whether S1 can see to it that S2 will y at t" by, say, having the right set attitudes. I’ll argue for this third position. As we’ll see, an important implication of this view is that consequentialists should be concerned not just with an agent’s voluntary actions but also with their involuntary acquisitions of various mental attitudes, such as beliefs, desires, and intentions. Indeed, I will argue that consequentialists should hold both that (1) an agent’s most fundamental duty is to have all those attitudes that she has decisive reason to have and only those attitudes that she has sufficient reason to have and that (2) she has a derivative duty to perform an act x if and only if her fulfilling this fundamental duty ensures that she x’s. Thus, I argue (as Donald Regan did before me) that consequentialism should not be exclusively act-orientated – that it should require agents not only to perform certain voluntary actions but also to have certain attitudes. In the process, I develop a new version of consequentialism, which I call attitude-consequentialism. (The latest version of this paper can always be found at: https://dl.dropboxusercontent.com/u/14740340/Consequentialism%20and%20Coordination%20Problems.pdf) -/- . (shrink)

Contrary to dictionaries, a non sequitur isn’t “any statement that doesn’t follow logically from previous statements”. Otherwise, every opening statement would be a non sequitur: a non sequitur is a statement claimed to follow from previous statements but that doesn’t follow. If the sentence making a given statement doesn’t contain ‘thus’, ‘so’, ‘hence’, ‘therefore’, or something else indicating an implication claim, the statement isn’t a non sequitur in this sense. But this is only one of several senses of that expression, (...) which, contrary to appearances, is a unitary common noun more properly written as one word: non-sequitur or nonsequitur. Above a nonsequitur was, roughly speaking, a conclusion of an invalid premise- conclusion argument, but not every such, only those that were stated to follow from premises that had been stated. Every informative proposition is the conclusion of an invalid argument. Anyway, nonsequiturs were not arguments. However, the expression ‘nonsequitur’ also means “invalid premise- conclusion argument”. It also means something like “fallacious reasoning” as in ‘Abe’s proof of the big-bang hypothesis is a nonsequitur’. The English noun is also used for an irrelevancy, an abrupt change of topic, or for any of many other expressions that are gratuitous, inappropriate, incongruous, or in some other way out of place. The English noun is derived from the Latin expression ‘non sequitur’, which is not a common noun but a sentence variously meaning “it isn’t in sequence ”, “it doesn’t follow”, “it is out of order”, etc. A statement that begins ‘in the second place’ is a nonsequitur if the previous sentence lacked implication of something like ‘in the first place’ or if it contained something similar to ‘in the third place’. In fact, a true implication claim can be a nonsequitur if there is no reason for making it. If Ben says ‘Hence, Abe swims and Abe swims’ in reply to Carl’s statement ‘Abe swims‘, then Ben may well be committing a nonsequitur. Many conversation stoppers are nonsequiturs. This lecture surveys and analyses a wide selection of uses of ‘nonsequitur’ in logic and logic-related literature. -/- END OF DRAFT 4 -/- NOTE 091215: When Rick Perry was discussing possible withdrawal from the race—unfortunately not the human race but the Republican race—a reporter reminded him that just last week Donald Trump predicted the Perry withdrawal. Perry interrupted with “A broken clock is right once a day”. -/- If you did not know Perry you might think his reply was a brilliant diversionary nonsequitur. If you know Perry you might think his reply was a stupid nonsequitur. -/- For the record, he did say ‘once a day’, not ‘twice a day’. BTW, my interjection ‘unfortunately not the human race but the Republican race’ was also a nonsequitur. (shrink)

The vertiginous rise of right-wing populism, especially in its “nationalist, xenophobic and conservative form”, and some “racist, anti-Semitic, homophobic and sexist” drifts associated with this phenomenon – whether real or perceived as such – make the mainstream media play a double role. On the one hand, the mainstream media reflect the struggle for political hegemony between different vested interests; on the other hand, they engage in the fight against right-wing populism blasting both right-wing populist candidates and their voters or supporters. (...) Many mainstream journalists ask citizens to realize a “sanitary cordon”, a “wall” or a “republican front” to block far-right populism and preserve liberal democracy. Moreover, they urge people to be wary of all attempts to “dediabolize” or “normalize” some tokens of right-wing populism. The main idea of this article is that right-wing populism is more harmless than is generally believed and, if excessive, negative media coverage doesn’t baffle but feed it. Populism is essentially a latent side effect of liberal democracy. Populism rises and becomes obtrusive only if a significant part of society perceives a regime of illiberal majoritarianism instead of one of liberal democracy. Right-wing populists are chiefly frustrated “ci-devants” who feel dispossessed of their past, identity, properties, qualities, privileges or titles. Inasmuch as the causes of collective frustration are many and varied (e.g. the real or just perceived corruption of the elites, the “system”, the deep state, the relocation of jobs, immigration, national sovereignty, national identity, communitarianism, radical Islamism, the status of some traditional institutions, some chapters of official history, etc.), there will always be right-wing populists, whether they are self-declared or covert. By adopting David G. Hackett’s thesis that the media are “agents of hegemony”, we applied the critical analysis of discourse to a set of 346 media articles in order to reveal the discursive sources of power, domination, inequality and partiality. The articles appeared in The New York Times and Le Monde during the period 2016-2017, at the time when the presidential elections took place in the United States and France. The articles were selected according to the occurrence of the keywords “Donald Trump” – “populism” and “Marine Le Pen” – “populisme” within the titles. The analysis of these articles reveals a divisive discursive structure that correspond to a real political cleavage in society. It is true that populism presents a “Manichean outlook”, in which there are only friends and foes” and no compromise is possible. It is also true that mainstream media reinforce this Manichean perspective on society and make populists feel marginalized and politically disempowered. The mainstream media may appease right-wing populism if they treat its followers as legitimate and equal political actors. For this, they have to give up the narrative structures that underscore insurmountable divergences and irreconcilable interests. In a liberal democracy, mass media should chiefly play the role of mediator. They may not aim to defeat or re-educate certain categories of citizens just because they advocate “wrong” political solutions. (shrink)

Anscombe claims that whenever a subject is doing something intentionally, this subject knows that they are doing it. This essay defends Anscombe's claim from an influential set of counterexamples, due to Davidson. It argues that Davidson's counterexamples are tacit appeals to an argument, on which knowledge can't be essential to doing something intentionally, because some things that can be done intentionally require knowledge of future successes, and because such knowledge can't ever be guaranteed when someone is doing something intentionally. The (...) essay argues that there are apparently sensible grounds for denying each of these two premises. (shrink)

INTRODUÇÃO O ovo da galinha consiste em uma célula reprodutiva bastante comparável às encontrada nos mamíferos. Todavia, no caso da galinha, essa célula reprodutiva localiza- se na superfície da gema, sendo preenchida por albumens, membranas de casca, casca e cutícula. O ovário é responsável pela formação da gema; as porções restantes do ovo originam-se no canal do oviduto. • OVÁRIO No momento do desenvolvimento precoce do embrião, existem dois ovários e dois ovidutos, entretanto o conjunto ovário-oviduto direito atrofia-se, deixando apenas (...) o ovário e o oviduto esquerdo funcional para a realização dos processos embrionários e de formação do ovo (feto). Antes da produção de óvulos, o ovário consiste em uma massa inerte de pequenos folículos que contém os óvulos. Alguns óvulos possuem estatura suficiente para serem vistos visualmente; outros requerem ampliação para serem detectados. A galinha possui inúmeros folículos presentes no ovário, que são capazes de suprir toda a produção de gemas da vida da ave. FORMAÇÃO DA GEMA A gema (figura 1) não é a verdadeira célula reprodutiva, mas como uma fonte de material alimentar a partir do qual a célula blastoderma e seu embrião resultante irão se sustentar durante o desenvolvimento. Quando uma franga atinge a maturidade sexual, o ovário e o oviduto sofrem algumas alterações. Cerca de 11 dias antes da fêmea colocar seu primeiro ovo, uma sequência de alterações hormonais ocorrem em seu organismo. O hormônio FSH (folículo estimulante) produzido pela glândula pituitária (hipófise) anterior faz com que os folículos ovarianos aumentem de tamanho, mas para que isso aconteça a fêmea deve ser exposta à luz, já que é o segundo fator relevante depois da nutrição adequada para a formação do ovo, uma vez que através do olho os estímulos da luz que entram no olho atingem as células nervosas até a hipófise que libera o FSH. Em suma, o ovário ativado começa a gerar hormônios como o estrogênio, progesterona e testosterona (esteroides sexuais). Os níveis plasmáticos mais elevados de estrogênio iniciam o desenvolvimento do osso medular, bem como estimula a produção de proteína albumina e a formação de lipídios (gordura) pelo fígado, além de aumentar o tamanho do oviduto, o que permite a produção de proteínas de albumina, membranas da casca, carbonato de cálcio para a formação da casca, e cutícula. A primeira gema (óvulo) que começa a amadurecer capta as grandes quantidades do material produzido pelo fígado e transportado pelo sistema circulatório diretamente para o ovário em desenvolvimento. Um ou dois dias depois da primeira, a segunda gema começa a se desenvolver, e assim por diante, até que no momento em que é posto o primeiro ovo, cerca de cinco a dez gemas já estão no processo de crescimento. É necessário em torno de 10 dias para que uma gema cresça e siga o caminho para se transformar num ovo posto. Depósitos de material de gema são lentos no início e possuem coloração clara. Eventualmente, o óvulo atinge um diâmetro de 6 mm, valor que cresce a uma taxa muito expressiva diária de até 4 mm. Um número maior de gemas encontram- se em desenvolvimento ao mesmo tempo em matrizes (galinhas reprodutoras) do que em poedeiras, no entanto a matriz não possui a capacidade de produzir uma taxa grande de ovos completos. A coloração presente na gema é xantofila, um pigmento carotenoides derivado da dieta do animal. O pigmento é transferido primeiro para a corrente sanguínea em função do processo de digestão e absorção, em seguida, rapidamente para a gema, bem como para outras partes do corpo como as penas. Consequentemente, em função da dieta, um teor mais elevado de xantofilas é depositado na gema durante as horas em que a galinha está comendo. Isso dá origem a depósitos de camadas escuras e claras no material da gema, dependendo do pigmento dietético disponível. Cerca de 7 a 11 anéis concêntricos são encontrados em cada gema. A formação de gemas é uniforme e a espessura total de depósitos de coloração clara e escura durante 24 horas é de cerca de 1,5 a 2,0 mm. A gema de ovo é composta basicamente de gorduras (lipídios) e proteínas, que combinam-se para a formação das lipoproteínas, das quais 60% do peso da gema é de lipoproteínas de baixa densidade (LDL), e são conhecidas por serem sintetizado pelo fígado através da ação do estrogênio. Na galinha poedeira, o LDL é removido do plasma sanguíneo como partículas intactas para a deposição do mesmo diretamente nos óvulos em desenvolvimento. Fatores que influenciam o crescimento da gema As gemas variam de tamanho entre as aves individuais de um aviário da mesma idade e são, geralmente, associados com as diferenças no peso corporal. O tamanho da gema não está associado a taxa de postura da ave, mas provavelmente com o tempo necessário para que os óvulos atinjam a maturidade e se desprendam. As gemas de uma galinha aumentam de tamanho ao longo do ciclo de produção. Além disso, o primeiro ovo posto em uma ninhada geralmente conterá uma gema maior do que os restantes. Os ovos colocados durante o final do dia são cerca de 0,5 gramas mais leves para cada hora adicional do dia; isso também está associado com gemas menores. A inclusão de gordura e proteína na dieta também demonstram um aumento significativo no tamanho da gema em desenvolvimento. Localização do disco germinativo O material da gema é colocado adjacente ao disco germinal (figura 1) que permanece na superfície da massa da gema globular. Uma vez que o ovo é posto, a gema gira para que o disco germinal permaneça na extremidade do ovo. OVULAÇÃO Quando a franga entra na maturidade, os óvulos são liberados do ovário para que possam entrar no canal do oviduto por um processo conhecido como ovulação. Cada óvulo encontra-se pendurado no ovário por uma haste estreita que contém as artérias que fornecem o sangue para a gema em desenvolvimento. As artérias sofrem diversas ramificações nas membranas superficiais da gema e o folículo têm um aspecto altamente vascular (figura 2), exceto pelo estigma, uma faixa estreita no entorno da gema que é quase desprovido de vasos sanguíneos. Figura 2: ovário com os folículos pequenos e prontos para se desprenderem. Fonte: IPA. Quando um óvulo está maduro, o hormônio progesterona, produzido pelo ovário, estimula o hipotálamo para causar a liberação do hormônio luteinizante (LH) da hipófise anterior que, por sua vez, faz com que o folículo maduro se rompa no local do estigma liberando o óvulo do ovário. A gema é então cercada apenas pela membrana vitelina (membrana da gema). Atraso da primeira ovulação A maturidade sexual, visualizada através da primeira ovulação da ave, pode ser acelerada ou retardada. Restringir a alimentação ou diminuir a duração do dia durante o período de crescimento da franga são os dois procedimentos principais para a agilizar o processo na galinha. O que inicia a ovulação? Não se sabe ao certo os parâmetros que definem a hora da primeira ovulação da ave, porém tanto o sistema nervoso quanto as secreções hormonais são de essencial importância na manifestação da mesma. A segunda ovulação é regulada mediante a oviposição (postura) do primeiro ovo cerca de 15 a 40 minutos após o primeiro ovo passar pelo canal da cloaca. As ovulações posteriores ocorrem com a mesma frequência em função dos ovos subsequentes serem postos. Ovos postos em ninhadas As galinhas põem ovos em dias sucessivos conhecidos como ninhadas, do qual nenhum é posto por um ou mais dias. O corrimento do ciclo da ninhada pode várias de 2 dias a mais de 200 antes de um dia é perdido, mas a maioria das poedeiras comerciais pode produzir mais de 50 ovos sucessivos, sem uma pausa durante as fases iniciais de produção no primeiro ciclo da ninhada. O comprimento da ninhada é bastante consistente nos indivíduos; as poedeiras com taxas de produção menores possuem um ciclo mais curto, enquanto que as grandes produtoras possuem ciclos mais longos. Uma vez que o comprimir do ciclo ninhada é estabelecido, a galinha não irá ovular por um ou mais dias e, em seguida, irá produzir outra ninhada. As poedeiras menos produtivas possuem um período de descanso mais longo entre as ninhadas do que as boas produtoras. Tempo necessário para produzir um ovo O tempo necessário para que um ovo atravesse o oviduto varia de acordo com os indivíduos. A maioria das galinhas põe ovos sucessivos com intervalos de tempo entre 23 a 26 horas. Se o tempo for maior que 24 horas, cada ovo será posto no final do dia. Os ovos postos à tarde passaram mais horas no oviduto do que os postos pela manhã. Eventualmente, os ovos são colocados tão tarde que o ritmo é quebrado e uma ovulação é pulada. Teoricamente, alguns autores dizem que o tempo ideal para uma boa formação de um ovo é de 25 horas. O óvulo se desprende do ovário entrando no canal do oviduto, permanece por 15 minutos no infundíbulo que é a primeira região do oviduto, em seguida o óvulo vai para o magno a segunda região do oviduto e permanece nessa região entre 2 a 3 horas. Em seguida, vai para o istmo, ficando nessa região entre 1 a 1,5 horas. Por último, vai para o útero permanecendo nessa região entre 18 a 20 horas. Por fim, vai para a vagina onde recebe um óleo, indo para a cloaca onde é posto. Tempo de ovulação As galinhas que produzem ninhadas mais longas colocam seu primeiro ovo no início do dia, uma ou duas horas após o nascer do Sol ou as luzes artificiais são ligadas. A ovulação da próxima gema acontece rapidamente após o primeiro ovo ser posto, com apenas um pequeno intervalo de tempo. As poedeiras com comprimentos mais curtos da ninhada colocam seu primeiro ovo mais tarde do dia, a ovulação da gema seguinte é mais lenta, e a defasagem de tempo para a postura é maior. A maioria das ovulações ocorre durante as primeiras horas da manhã, já que não é natural que a ovulação ocorra em meados do final da tarde. Produção de ovos no início da postura Durante a primeira semana de postura, a ovulação é bastante irregular, uma vez que o mecanismo hormonal da galinha não está em equilíbrio. Na maioria das vezes, apenas dois a quatro ovos são produzidos na primeira ninhada. Entretanto, na segunda ou terceira semana, a ovulação irá progredindo gradativamente em sua taxa de pico até cair lentamente a cada semana durante o restante do ciclo de postura. Luz e ovulação A luz, seja natural ou artificial, possui um efeito direto sobre a glândula pituitária, estimulando-a a segregar uma quantidade maior do hormônio FSH que, por sua vez, ativa a região ovariana. A duração e a intensidade da luz são fatores importantes no processo de planejamento de uma granja, bem como durante a fase de postura. O procedimento para iluminar corretamente um galpão de galinhas poedeiras não é uma tarefa fácil e será discutido trabalhos posteriores. Nidificação como indicação de ovulação Na maioria das vezes, a galinha procura um ninho cerca de 24 horas após a ovulação, levando aos pesquisadores a teorizar que a nidificação pode ser usada como um fator de indicação da ovulação. Evidentemente, a presença de um ovo totalmente formado na cloaca não tem nada a ver com o desejo da galinha de procurar um ninho. Por exemplo, algumas galinhas irão ovular, todavia por causa de um imprevisto, o óvulo não chega ao oviduto, essas mesmas galinhas ainda irão procurar um ninho no dia seguinte. Ovulação dupla Normalmente, apenas uma gema é ovulada por dia, entretanto, ocasionalmente duas gemas podem ser liberadas e, em raras ocasiões até três gemas podem ser liberadas. Se duas gemas serão ovuladas ao mesmo tempo, normalmente apenas uma entra no canal do oviduto, mas se ambas são apanhadas simultaneamente pelo oviduto, resultará em um ovo de gema dupla (figura 3). Cerca de dois terços dos ovos de gema dupla são resultantes de ovulações dentro de 3 horas de um para o outro. Se houver uma grande diferença de tempo de ovulação, dois ovos poderão ser produzidos no mesmo dia, porém na maioria das vezes o segundo ovo possui casca mole ou apenas é revestido por uma membrana (figura 4). Geralmente, os ovos de gema dupla são mais comuns durante a primeira parte do período de produção do ovo causados por um ovário hiperativo e, frequentemente, são associados com frangos de corte do que com galinhas poedeiras. A incidência é um traço herdado, uma vez que algumas aves mais velhas produzem um percentual maior de ovos com gema dupla do que outras, sendo assim, a característica pode ser hereditária. As aves criadas na estação da Primavera e no Verão também produzem um número maior de ovos de gema dupla do que as galinhas criadas no Outono e no Inverno. Figura 3: ovo de gema dupla. Fonte: IPA. Figura 4: ovo com casca mole. Fonte: IFPE. CASCA DE OVOS DEFEITUOSAS Quando o intervalo normal de 23 a 26 horas entre as ovulações é quebrado, mais ovos são produzidos com casca defeituosas (figuras 4 e 5), incluindo aqueles com textura de lixa, bandas brancas, salpicos de cálcio e depósitos de calcário. A ocorrência é maior em ovos de matrizes do que em poedeiras. Cerca de 5 a 7% dos ovos produzidos por uma matriz poderá apresentar alguma forma de deformações na casca. Esses defeitos estão associados principalmente com a idade do lote e com as raças mais propensas ao problema do que outras. Figura 5: deformações na casca do ovo. Fonte: internet. TAMANHO DA GEMA AFETA O TAMANHO DO OVO O tamanho do ovo normal está associado mais com o tamanho da gema do que com qualquer outros fator relevante, embora as variações nas secreções de albumina no oviduto possam ter alguma influência. A relação gema-albumina muda ao longo do ciclo de postura. Os ovos que são produzidos no início do período de postura possuem gemas que representam em torno de 25% do peso total do ovo, enquanto que as gemas compõem cerca de 30% do peso do ovo quando as galinhas estão perto do final do período de postura. Em outras palavras, à medida em que o tamanho do ovo aumenta, o peso da gema aumenta mais rapidamente do que o peso do albúmen. Em lotes de frangas, quando o tamanho do ovo é pequeno, o aumento de proteína na dieta pode aumentar o peso total até 3,5 g/cada. MANCHAS DE SANGUE E DE CARNE Muitas vezes, quando o saco vitelino se rompe ao longo do estigma, pequenos vasos sanguíneos perto da área da ruptura são quebrados, formando um coágulo de sangue ligado à gema. A frequência de hemorragias pode estar relacionada com uma série de fatores, como a genética, alimentação, idade da galinha etc. As manchas de sangue são de duas a três vezes mais comuns em galinhas que produzem ovos de casca marrom do que em galinhas poedeiras de casca branca. Qualquer tecido deslocado do saco folicular ou do oviduto poderá ser incluído ao ovo em desenvolvimento à medida que passa pelo oviduto. Esses pedaços de tecido escurecem com a idade e são conhecidos como manchas de carne. Muitas manchas de sangue escurecem também, e muitas vezes são classificadas de forma incorreta como manchas de carne. Este problema é especialmente prevalente em ovos de casca marrom, onde 15% ou mais dos ovos podem ser afetados, em comparação com menos de 1% em ovos de casca branca. Figura 6: ovo com mancha de carne e com mancha de sangue. Fonte: internet. • PARTES DO OVIDUTO O oviduto é um tubo lindo através do qual a gema passa e onde os componentes restantes do ovo como a clara e a casca são incorporados. Normalmente, o oviduto é relativamente pequeno em diâmetro, mas com a aproximação da primeira ovulação seutamanho e espessura se expandem de forma significativa para que possa favorecer a passagem e o desenvolvimento do ovo. Os segmentos do oviduto e sua finalidade serão resumidos no texto abaixo e ilustrados na figura 7 e 8. INFUNDÍBULO A porção superior do oviduto que possui uma formato de funil é denominada infundíbulo. Quando encontra-se funcional, seu comprimento é de aproximadamente 9 cm. Normalmente é inerte, exceto quando ocorre a ovulação, seu objetivo é captar a gema ou óvulo que se desprende do ovário para que a mesma entre no oviduto, por isso a forma de funil. Após a ovulação, a gema entra na bolsa ovariana ou na cavidade do corpo, a partir da qual é capturada pelo infundíbulo. A gema permanece nessa secção por apenas um curto período de cerca de 15 minutos, depois é forçada ao longo do oviduto através das várias contrações ou movimentos peristálticos. Mau funcionamento do infundíbulo Para que o infundíbulo seja completamente funcional, ele deve capturar todas as gemas que se desprendem do ovário e caiu na cavidade do corpo. No entanto, verificou- se que uma média de 4% das gemas não são atraídas para o segmento, porém permanecem na cavidade do corpo onde são reabsorvidas dentro de um dia. A porcentagem de gemas retidas varia entre as várias linhagens de galinhas, algumas podem reter até 10% de suas gemas na cavidade corporal. As matrizes são as mais afetadas do que as poedeiras. Camadas internas Às vezes, o infundíbulo perde a sua capacidade de captação de uma alta proporção de gemas, e acabam acumulando-se na cavidade do corpo mais rápido do que possam ser reabsorvidas. Tal problema é definido por “camadas internas”, embora o termo não defina de forma clara a condição. O abdômen em tais camadas torna-se distendido, e a galinha fica em uma posição ereta. MAGNO O magno é a porção secretória de albúmen do oviduto, possui cerca de 33 cm de comprimento nas poedeiras em média. Demora aproximadamente cerca de 2 a 3 horas para passagem do ovo em desenvolvimento passar pelo magno. Albúmen O albúmen em um ovo é composto por quatro camadas, sendo elas: Chalaza ou calaza 2,7% Líquido branco exterior 16,8% Densidade branca 57,3% Branco fino exterior 23,2% Fonte: BELL. Enquanto todos os quatro são produzidos no magno, o branco fino exterior não é concluído até que a água seja adicionada no útero. Chalaza ou calaza Ao quebrar um ovo, percebe-se duas partes torcidas conhecidas como calaza, estendendo-se de polos opostos da gema através do albúmen. L albúmen calcífero é produzido quando a gema entra pela primeira vez no magno, mas a torção para formação dos dois calazas acontece mais tardiamente, como o ovo gira na extremidade inferior do oviduto. Torcidas em direções opostas, a calaza tende a manter a gema no centro do ovo depois que ele é posto. Líquido interior branco À medida que o ovo em desenvolvimento passa pelo magno, apenas um tipo de albúmen é produzido, porém a adição de água juntamente com a rotação do ovo dão origem a várias outras camadas, uma delas e a expressiva é o líquido interno de coloração branca. Densidade branca O branco denso constitui a maior parte do ovo. Contém muco que tente a mantê- lo juntos. A quantidade de branco espesso gerada no magno é grande, mas a degradação da mucina e a adição de água, já que o ovo move-se através do oviduto, tendem a reduzir a quantidade desse líquido denso e grosso, aumentando a quantidade do branco fino. No momento em que o ovo é posto, ele possui cerca de um terço do seu conteúdo original de clara, porém o restante ainda compreende mais da metade do albúmen no ovo. Deterioração da qualidade dos ovos Após a postura dos ovos, há uma mudança constante no conteúdo interno do ovo. A clara é a primeira que começa a perder gradualmente a sua composição viscosa e o seu volume diminui, enquanto que o branco fino fica mais aguado e sua quantidade aumenta. Essas condições são afetadas pela temperatura de retenção, umidade relativa, tempo e certas doenças. A quantidade crescente de branco fino é um dos melhores indicadores das condições de idade (frescura) dos ovos. ISTMO Depois da passagem pelo magno, o ovo em desenvolvimento é forçado para o istmo, uma secção relativamente curta de aproximadamente 10 cm de comprimento, onde permanece entre 1 a 1,5 horas (média geral de 75 minutos). Aqui, as membranas da casca interna e externa são formadas de modo a representar a dona final do ovo. O conteúdo presente nesse momento não é suficiente para preencher completamente as membranas da casca, e o ovo assemelha-se a um saco parcialmente preenchido. As membranas da casca são um material parecido com um papel composto de fibras proteicas. A membrana interna estabelece-se primeiro, seguida pela membrana externa, que é três vezes mais grossa que a membrana interna. As duas membranas são mantidas juntas até que o ovo seja posto; em seguida, na extremidade do ovo, as duas membranas se separam para formar a célula de ar, essencial para a respiração do feto no caso de ovos de matrizes. Em uma pequena porcentagem dos ovos, a célula de ar se formará na extremidade pequena ou nas laterais. Importância da célula ou câmara de ar Quando o ovo é posto pela primeira vez não há célula de ar. Ela é estabelecida através da redução de temperatura e aumenta de diâmetro para cerca de 1,8 cm conforme a perda de água do ovo por evaporação. À medida em que o ovo envelhece, a umidade ou presença d água dentro do mesmo evapora através dos poros presentes na casca e a câmara de ar aumenta em diâmetro e profundidade. O tamanho da célula de ar pode ser afetado por várias condições de armazenamento. A alta temperatura circundante e/ou a baixa umidade aumentam o tamanho da câmara de ar. O tamanho da célula, conforme determinado pela ovoscopia, é usado em programas de classificação de julgamento da idade do ovo. As células de ar maiores são prerrogativas de pior qualidade interior. Membranas da casca atuam como barreiras As membranas da casca atuam como uma barreira à penetração de organismos microscópios tais como as bactérias que podem afetar diretamente a qualidade do mesmo para consumo ou o embrião em desenvolvimento. Os ovos postos por frangas possuem membranas de casca mais espessas do que os ovos postos por galinhas mais velhas, o que se determina que conforme a idade da ave, as membranas protetoras vão ficando mais finas o que pode levar a penetração de microrganismos que afetam a qualidade do ovo. ÚTERO (GLÂNDULA DA CASCA) O útero é o penúltimo caminho do ovo em desenvolvimento, possui cerca de 10 a 12 cm de comprimento nas galinhas poedeiras. O ovo em desenvolvimento normalmente permanece no útero de 18 a 20 horas, muito mais do que em qualquer outra seção do oviduto. Exterior fino branco depositado após as membranas da casca Quando o ovo entra pela primeira vez no útero, a água e os sais minerais são depositados através das membranas da casca pelo processo de osmose de dentro para fora das membranas da casca de forma gradativa e aderindo para liquefazer alguns dos albumens finos que formam a quarta camada, o branco fino exterior. A casca A calcificação da casca do ovo começa antes do mesmo entrar no útero. Pequenas quantidades de Ca aparecem na membrana externa da casca pouco antes do ovo deixar o istmo. Esses são os locais de iniciação para a deposição de cálcio no útero. A quantidade de Ca provavelmente herdada desempenha um papel primordial na deposição de Ca mais tarde no ovo. Eles desaparecem pouco tempo depois que o ovo entra na glândula da casca ou útero. A primeira camada da casca é depositada sobre os locais de iniciação (istmo) que forma a casca interna, uma camada composta de cristais de calcita que é um material com característica esponjosa. Essa camada é seguida pela adição da camada externa, que é composta por uma camada de cristais de calcita que são os calcários, camada que possui cerca de duas vezes mais espessura que a superfície interna da casca. Quanto mais longas forem as colunas de calcita, mais forte será a casca. A casca do ovo quando completa, é composta quase inteiramente de carbonato de cálcio (CaCO3), com pequenas quantidades de sódio, potássio e magnésio. Figura 9: carbonato e fórmula do cálcio presente no útero e istmo. Fonte: internet. Fontes de cálcio para a casca de ovo Existem apenas duas fontes de cálcio para a produção da casca, a alimentação e os ossos que atuam como locais de armazenamento de cálcio no corpo. Normalmente, a maioria do Ca para a formação dos ovos vem diretamente da ração que a ave come, com alguns derivados do osso medular que serve como reservatório de Ca. O reservatório é particularmente importante à noite, quando a ave não está comendo e a casca do ovo está em processo de desenvolvimento. Formação do carbonato de cálcio O carbonato de cálcio (figura 9) é formado quando os íons de Ca presentes no sangue e os íons carbonatos do sangue e da glândula da casca ou útero se combinam no útero. Qualquer fator que reduza o fornecimento de qualquer um desses íons interfere com a formação de CaCO3 e o desenvolvimento da casca do ovo, muitas vezes resultando em baixa qualidade da casca, que será discutida em outros trabalhos. Acredita-se que as altas temperaturas ambientais também podem contribuir para este problema, uma vez que as cascas de ovos são mais finas durante o tempo quente. Qualidade da casca Muitos fatores podem causar uma deterioração na qualidade da casca do ovo, e a influência desse má qualidade pode não ser em função do fornecimento inadequado de íons de cálcio ou carbonato. A qualidade da casca é, geralmente, definida como a capacidade da casca de suportar o choque, sua aparência geral e suavidade. A resistência da casca pode ser medida mediante várias técnicas, incluindo a resistência à quebra, gravidade específica, deformações e espessura da mesma. Vários fatores podem reduzir a qualidade da casca, por exemplo: 1. A qualidade é reduzida à medida que a ave envelhece e continua a postura, uma vez que a galinha não pode produzir de forma eficiente a quantidade adequada de carbonato de cálcio para cobrir os ovos maiores produzidos durante a última parte do ciclo de postura, mesmo com o Ca presente na ração de consumo. 2. Aumento das temperaturas ambientais. 3. Ovos postos de manhã possuem uma qualidade da casca inferior à dos ovos postos pela tarde. 4. Estresse experimentado pelas aves que receberam chuva ou que foram, de alguma forma, submetidas à água. 5. Praticamente todos os ovos deformados e os ovos submetidos a controles corporais são postos entre às 6 e 8 horas da manhã, complemento do item 3. 6. Certas doenças como a bronquite infecciosa e a doença de Newcastle. 7. Determinados antibióticos ou outros fármacos. Necessidades de cálcio durante a produção A demanda da poedeira por Cá é extremamente alta. As aves poedeiras requerem mais Ca para a produção de ovos para consumo do que as matrizes reprodutoras que produzem pintainhos. Uma galinha de 2 kg produzindo 250 ovos de 56,7 gramas em média por ano requer cerca de 560 gramas de Ca. Uma vez que essa quantidade é 25 vezes maior que a quantidade de Ca presente no esqueleto da ave, é evidente que a necessidade alimentar de Ca seja grande. A maioria das rações de postura contém de 3 a 4% de Ca para atender as necessidades e permitir as ineficiências de absorção do Ca para o corpo e sim para o ovo. Figura 10: estrutura do ovo e da casca. Fonte: Adaptação da internet. Poros da casca do ovo As duas camadas da casca do ovo interna e externa possuem pequenas aberturas chamadas poros. Em um ovo pode haver até 8000 poros. Através dessas pequenas aberturas, o ar consegue passar para o ovo e fornece oxigênio para o embrião em desenvolvimento. Além disso, o dióxido de carbono e a umidade são removidos do ovo passando por esses mesmos poros. No ovo recém-posto, os poros presentes são quase completamente fechados, porém à medida que o ovo envelhece ou é lavado, o número de poros abertos aumenta. Cor da casca A casca do ovo é predominantemente branca ou marrons. No entanto, uma raça sul-americana, a Araucana, produz ovos de casca verde ou azul. Os pigmentos produzidos no útero no momento em que a casca é produzida são os responsáveis pela coloração. O tom de coloração é bastante consistente de acordo com cada ave, com a intensidade da cor sendo uma derivação da composição genética do indivíduo. Algumas linhagens de aves põem ovos com cascas castanhas mais escuras, enquanto que outras podem variar até ao branco. O pigmento marrom nas cascas de ovos é a porfirina, uniformemente distribuída por toda a casca. A cutícula A cutícula é colocada na parte externa da casca no útero e representa a última das camadas de formação dos ovos. É composta principalmente de material orgânico. Contém uma alta porcentagem de água e atua como lubrificante natural durante o processo de postura. Todavia, uma vez que o ovo é posto, o material da cutícula seca rapidamente, selando os poros da casca o que ajuda a evitar uma troca rápida de ar e umidade entre o interior do ovo e o ambiente externo, além de vedar a passagem de bactérias e outros microrganismos que podem afetar a qualidade ou o embrião. Vários processos de limpeza da casca (lavagem e desinfecção) reduzem a eficácia da cutícula. Para evitar esse problema, os processadores de ovos comumente aplicam um revestimento de óleo mineral na superfície da casca durante o processamento. Tal óleo ajuda a diminuir a perda de umidade e mantém a qualidade interna do ovo. REFERÊNCIAS BIBLIOGRÁFICAS ALBINO, L. F. T. et al. Galinhas poedeiras: Criação e alimentação. Viçosa: Aprenda Fácil, 2014. Anotações de aulas. Disciplina: Avicultura. Prof. Me. Cléber Rondinelli Gomes de Freitas. IFPE Campus Belo Jardim, 2017. BELL, Donald D. Formation of the egg. In: Commercial chicken meat and egg production. Springer, Boston, MA, 2002. p. 59-69. COTTA, Tadeu. Galinha: produção de ovos. Viçosa: Aprenda Fácil Editora, 2002. COTTA, T. Reprodução da galinha e produção de ovos. Lavras: UFLA-Faepe, p. 81- 92, 1997. DE MORAES, Ismar Araujo. Fisiologia da reprodução das aves domésticas. Fisiovet, 2006. FLORIANO, Luciane Sperandio. Anatomia e fisiologia das aves domésticas. Ururaí: rede E-tec, 2018. GRAU, C. R. Egg formation. In: Seabird energetics. Springer, Boston, MA, 1984. p. 33- 57. LANA, Geraldo Roberto Quintão. Avicultura. Recife: Livraria e Editora Rural Ltda, 2000 PERRINS, C. M. Eggs, egg formation and the timing of breeding. Ibis, v. 138, n. 1, p. 2- 15, 1996. STURKIE, Paul D. Fisiología aviar. Zaragoza: Acribia, 1967. (shrink)

How should we understand the relationship between the contents of our color, causal, modal, and evaluative beliefs, on the one hand, and color, causal, modal, and evaluative properties, on the other? According to Barry Stroud (2011), because of the nature of the contents of those types of beliefs, we should also think that what he calls a “negative metaphysical verdict” on the latter is not one that we could consistently maintain. The metaphysical project aims to arrive at an improved conception (...) of ourselves and our relation the world, no matter if that conception is positive or negative. But if Stroud is right that we cannot consistently arrive at the view that all of our causal, modal, and evaluative beliefs are systematically false, we will see that we cannot consistently reach the negative verdict. But failure to reach the negative verdict doesn’t mean that we have reached the positive verdict. Stroud calls this philosophical failure “metaphysical dissatisfaction”. In this paper, I argue that we can appropriate a metaepistemological response to the problem of the external world which shares its core features with Stroud’s (2000, 2011) arguments, but which nevertheless leaves us with a distinctive kind of epistemological dissatisfaction. (shrink)

This chapter argues that Davidson's truth-theoretic semantics was not intended to replace the traditional pursuit of providing a compositional meaning theory but rather to achieve the same aim indirectly by placing conditions on a truth theory that would enable someone who understood it to understand its object language. The chapter argues that by placing constraints on the axioms of a Tarski-style truth theory, namely, that they interpret the terms for which they give satisfaction conditions, and specifying a suitable canonical proof (...) procedure that issues in T-sentence that remove all the metalanguage semantic terms from the right hand side and draw intuitively only on the content of the axioms, we can use the theory to interpret object language sentences. It further argues that if we ask what body of knowledge one must be in possession of to interpret the language, it turns out to be a set of propositions about the truth theory but not the axioms of the truth theory itself. This shows how to avoid the problem of the semantic paradoxes and the problem of vagueness. (shrink)

Despite recent neuroscientific research purporting to reveal that free will is an illusion, this paper will argue that agency is an inescapable feature of rationality and thought. My aim will not be to address the methodology or interpretation of such research, which I will only mention in passing. Rather, I will examine a collection of basic concepts which are presupposed by thought, and propose that these concepts are interrelated in ways that makes them both basic and irreducibly complex. The collection (...) includes such concepts as belief, value, meaning, and truth. I will argue that free will belongs to this collection, and as such is also presupposed by thought. This proposal is opposed to a methodological tendency in analytic philosophy, to eliminate aspects of concepts which can’t be given a clear analysis, and to the wish of many empirical psychologists and cognitive scientists to reduce intentional/mental states to neurons and other mindless phenomena which they regard as more fundamental. Instead of offering a direct critique of either of these methodological attitudes, I will try to place the concept of freedom in its proper conceptual context, and make a positive case for its reality. (shrink)

While holism and atomism are often treated as mutually exclusive approaches to semantic theory, the apparent tension between the two usually results from running together distinct levels of semantic explanation. In particular, there is no reason why one can’t combine an atomistic conception of what the semantic values of our words are (one’s “descriptive semantics”), with a holistic explanation of why they have those values (one’s “foundational semantics”). Most objections to holism can be shown to apply only to holistic version (...) of descriptive semantics, and do not tell against any sorts of holistic foundational semantics. As Davidson’s work will be used to illustrate, by clearly distinguishing foundational and descriptive semantics, one can capture the most appealing features of both holism and atomism. (shrink)

In this chapter, we defend the view that Davidson aimed not to replace the theory of meaning with the theory of truth, or to capture only certain features of the ordinary notion of meaning for certain theoretical purposes, but rather to pursue the traditional project of explaining in the broadest terms “what it is for words to mean what they do” through a clever bit of indirection, namely, by exploiting the recursive structure of a Tarskian‐style truth theory, which meets certain (...) constraints in an illuminating way, to generate theorems that give truth conditions for object language sentences that at the same time provide interpretations of them. (shrink)

This essay interprets Butler’s distinction between identity in the loose and popular sense and in the strict and philosophical sense. Suppose there are different standards for counting the same things. Then what are two distinct things counting strictly may be one and the same thing counting loosely. Within a given standard identity is one-one. But across standards it is many-one. An alternative interpretation using the parts-whole relation fails, because that relation should be understood as many-one identity. Another alternative making identity (...) relative to sort fails, because whole and parts can be of the same sort. (shrink)

I argue that an individual has aspects numerically identical with it and each other that nonetheless qualitatively differ from it and each other. This discernibility of identicals does not violate Leibniz's Law, however, which concerns only individuals and is silent about their aspects. They are not in its domain of quantification. To argue that there are aspects I will appeal to the internal conflicts of conscious beings. I do not mean to imply that aspects are confined to such cases, but (...) the best way to start is to recognize them experientially. We can feel the conflicts within ourselves. In doing so we can feel some of our aspects. I will try to enhance our understanding of the concept of aspect by listing and formalizing some principles for its use. After that I will argue that all sorts of individual things have aspects, not just people who are conflicted. (shrink)

Construing the instantiation of a universal by a particular in terms of my theory of aspects resolves the basic mystery of this "non-relational tie", and gives theoretical unity to the four characteristics of instantiation discerned by Armstrong. Taking aspects as distinct in a way akin to Scotus's formal distinction, I suggest that instantiation is the sharing of an aspect by a universal and a particular--a kind of partial identity. This approach allows me to address Plato's multiple location and One over (...) Many problems, Bradley's problem concerning the instantiation of relations, and the problem of change. (shrink)

There is more than one way to say that composition is identity. Yi has distinguished the Weak Composition thesis from the Strong Composition thesis and attributed the former to David Lewis while noting that Lewis associates something like the latter with me. Weak Composition is the thesis that the relation between the parts collectively and their whole is closely analogous to identity. Strong Composition is the thesis that the relation between the parts collectively and their whole is identity. Yi is (...) right that Strong Composition does not fully reflect my view. We must recognize further what, borrowing Lewis's characterization, could be called the "stronger, and stranger" Composition thesis, or what I'll call the Stronger Composition thesis for short. On Strong Composition, it is only collectively that the parts are identical with the whole. On Stronger Composition, they are individually identical with it as well. I will explain and motivate this thesis. (shrink)

Two things become one thing, something having parts, and something becoming something else, are cases of many things being identical with one thing. This apparent contradiction introduces others concerning transitivity of identity, discernibility of identicals, existence, and vague existence. I resolve the contradictions with a theory that identity, number, and existence are relative to standards for counting. What are many on some standard are one and the same on another. The theory gives an account of the discernibility of identicals using (...) phrases like “insofar as”. And it holds that standards for counting remain or shift depending on our purposes. (shrink)

How is it possible for David Hume to be both withering skeptic and constructive theorist? I recommend an answer like the Pyrrhonian answer to the question how it is possible to suspend all judgment yet engage in active daily life. Sextus Empiricus distinguishes two kinds of assent: one suspended across the board and one involved with daily living. The first is an act of will based on appreciation of reasons; the second is a causal effect of appearances. Hume makes the (...) same distinction, only he extends the sort of assent involved in daily life to theoretical matters as well. He is a skeptic both in finding no reason to grant the first sort of assent and in being subject to the second. (shrink)

I argue via examples that there are cases in which things that are not two distinct things qualitatively differ without contradiction. In other words, there are cases in which something differs from itself. Standard responses to such cases are to divide the thing into distinct parts, or to conceive of the thing under different descriptions, or to appeal to different times, or to deny that the property had is the property lacked. I show these responses to be unsatisfactory. I then (...) gather and systematize available ways of talking about such cases with phrases like ‘insofar as’, ‘qua’, ‘to the extent that’, ‘in some respect’, etc., while paying special attention to the scope of ‘not’ when used with these phrases. This allows me to show how we can speak of self-differing without contradiction. (shrink)

ABSTRACT According to David Lewis, alteration is "qualitative difference between temporal parts of something." It follows that moments, since they are simple and lack temporal parts, cannot alter from future to present to past. Here then is another way to put McTaggart's paradox about change in tense. I will appeal to my theory of Aspects to rebut the thought behind this rendition of McTaggart. On my theory, it is possible that qualitatively differing things be numerically identical. I call these differing, (...) numerically identical things "aspects." I will argue that alteration can be a qualitative difference between temporal aspects of something that lacks temporal parts. So a moment can alter in tense. By rejecting Lewis's assumption my theory can solve this version of McTaggart's paradox. (shrink)

Confucius gave counsel that is notoriously hard to follow: "What you do not wish for yourself, do not impose on others" (Huang 1997: 15.24). People tend to be concerned with themselves and to be indifferent to most others. We are distinct from others so our self-concern does not include them, or so it seems. Were we to realize this distinctness is merely apparent--that our true self includes others--Confucius's counsel would be easier to follow. Concern for our true self would extend (...) concern beyond the narrow selves we appear to be. The neo-Confucians held just such a view. They espoused an identity with the universe and everything in it, arguing that this identity explains a natural concern for everyone and everything, not just for our narrow selves. However, many things in the universe differ from each other, that is, some have qualities others lack. If they are all one and the same thing then that one thing differs from itself. I will suggest that the objection can be answered with some metaphysical innovation. I will address the objection by sketching a theory--call it the theory of aspects--that explains how numerically identical things can differ qualitatively. (shrink)

Hume discusses the distinction of reason to explain how we distinguish things inseparable, and so identical, e.g., the color and figure of a white globe. He says we note the respect in which the globe is similar to a white cube and dissimilar to a black sphere, and the respect in which it is dissimilar to the first and similar to the second. Unfortunately, Hume takes these differing respects of resemblance to be identical with the white globe itself. Contradiction results, (...) undermining his theory of abstraction. The way out is apparently to admit an intrinsic complexity in even simple things. (shrink)

_Groups in Conflict_ addresses the conflict and tensions that exist between impartiality and partiality in political philosophy, ordinary thought, and practice by setting theoretical arguments in the context of contemporary issues such as immigration and public policy. Donald Franklin asserts that two camps of ethicists—those concerned with political philosophy and those concerned with personal morality—have been ignoring the implications of inconsistency in their mutual approaches. Far more than just exposing these irreconcilable differences, Franklin also proposes the modifications necessary to (...) approach the nature of human equality. (shrink)

Ordinary usage gives a way to think of identity through time: the Pittsburgh of 1946 was the same city as the Pittsburgh of today is--namely Pittsburgh. Problem: The Pittsburgh of 1946 does not exist; Pittsburgh still does. How can they have been identical? I reject the temporal parts view on which they were not but we may speak as though they were. Rather I argue that claiming their identity is not contradictory. I interpret ‘the Pittsburgh of 1946’ as ‘Pittsburgh as (...) it was in 1946’ and suggest that the apparent contradiction results from an ambiguity in the scope of ‘as’. (shrink)

To the question whether Hume believed in mind-independent physical objects (or as he would put it, bodies), the answer is Yes and No. It is Yes when Hume writes “We may well ask, What causes induce us to believe in the existence of body? but ’tis in vain to ask, Whether there be body or not? That is a point, which we must take for granted in all our reasonings.” However the answer is No after inquiring into the causes of (...) that belief, when he writes, “What then can we look for from this confusion of groundless and extraordinary opinions but error and falsehood? And how can we justify to ourselves any belief we repose in them?” My view is that Hume’s Yes and No answers can best be accounted for by seeing him as a Pyrrhonian skeptic in the tradition of Sextus Empiricus. This interpretation, while finding considerable truth in the various positions canvassed, is closest to those of Norton, Fogelin, and especially Popkin. (shrink)

One of the advantages of my account in the essay “Instantiation as Partial Identity” was capturing the contingency of instantiation—something David Armstrong gave up in his experiment with a similar view. What made the contingency possible for me was my own non-standard account of identity, complete with the apparatus of counts and aspects. The need remains to lift some obscurity from the account in order to display its virtues to greater advantage. To that end, I propose to respond to those (...) who have grappled with it in print. There are various criticisms by commentators: that it is rendered absurd by the transitivity of identity, that it makes instantiation necessary instead of contingent, that it is unclear what counts are, that aspects are simply tropes, that my view does not capture multiple location, that I make an unclear reference to a theory of composition as identity, that the account suffers from problems with polyadicity, and that it is not a realist account of universals after all. I give responses to these objections. (shrink)

The paper has two complementary objectives. First, it sustains an analysis of the concept of ‘coloniality’ that accounts for the epistemic imbalance in the modern world, demonstrating precisely how Africa is adversely affected, having been caught up in the throes of coloniality and its epistemic implications. Second – and complementarily – the paper attempts to bring this very concept of ‘coloniality’ into the discourse on Africa’s emigration crisis, arguing that Africa’s emigration crisis is traceable, inter alia, to the epistemic imbalance (...) in the very structure of modernity. This imbalance results from the stifling of Africa’s epistemic resources under Western epistemic hegemony. Epistemic coloniality, of course interacting with some material factors, creates a sufficient condition for emigration. It is further theorized that the apparent lack of epistemic will on the part of Africans to mobilize some surviving epistemic resources to address some problems on their own is also a function of coloniality. (shrink)

Neo-Humean instrumentalist theories of reasons for acting have been presented with a dilemma: either they are normatively trivial and, hence, inadequate as a normative theory or they covertly commit themselves to a noninstrumentalist normative principle. The claimed result is that no purely instrumentalist theory of reasons for acting can be normatively adequate. This dilemma dissolves when we understand what question neo-Humean instrumentalists are addressing. The dilemma presupposes that neo-Humeans are attempting to address the question of how to act, 'simpliciter'. Instead, (...) they are evaluating actions from the agent's normative perspective. (shrink)

Hume's Treatise arguments concerning space, time, and geometry, especially ones involving his denial of infinite divisibility; have suffered harsh criticism. I show that in the section "Of the ideas of space and time," Hume gives important characterizations of his skeptical approach, in some respects Pyrrhonian, that will be developed in the rest of the Treatise. When that approach is better understood, the force of Hume's arguments can be appreciated, and the influential criticisms of them can be seen to miss the (...) mark. (shrink)

In this paper, I critically discuss one of the more influential arguments for mereological universalism, what I will call ‘the Vagueness Argument’. I argue that a premise of the Vagueness Argument is not well supported and that there are at least two good reasons for thinking that the premise in question is false.