It is widely alleged that metaphysical possibility is “absolute” possibility Conceivability and possibility, Clarendon, Oxford, 2002, p 16; Stalnaker, in: Stalnaker Ways a world might be: metaphysical and anti-metaphysical essays, Oxford University Press, Oxford, 2003, pp 201–215; Williamson in Can J Philos 46:453–492, 2016). Kripke calls metaphysical necessity “necessity in the highest degree”. Van Inwagen claims that if P is metaphysically possible, then it is possible “tout court. Possible simpliciter. Possible period…. possib without qualification.” And Stalnaker writes, “we can agree (...) with Frank Jackson, David Chalmers, Saul Kripke, David Lewis, and most others who allow themselves to talk about possible worlds at all, that metaphysical necessity is necessity in the widest sense.” What exactly does the thesis that metaphysical possibility is absolute amount to? Is it true? In this article, I argue that, assuming that the thesis is not merely terminological, and lacking in any metaphysical interest, it is an article of faith. I conclude with the suggestion that metaphysical possibility may lack the metaphysical significance that is widely attributed to it. (shrink)

It is often supposed that, unlike typical axioms of mathematics, the Continuum Hypothesis (CH) is indeterminate. This position is normally defended on the ground that the CH is undecidable in a way that typical axioms are not. Call this kind of undecidability “absolute undecidability”. In this paper, I seek to understand what absolute undecidability could be such that one might hope to establish that (a) CH is absolutely undecidable, (b) typical axioms are not absolutely undecidable, and (c) if a mathematical (...) hypothesis is absolutely undecidable, then it is indeterminate. I shall argue that on no understanding of absolute undecidability could one hope to establish all of (a)–(c). However, I will identify one understanding of absolute undecidability on which one might hope to establish both (a) and (c) to the exclusion of (b). This suggests that a new style of mathematical antirealism deserves attention—one that does not depend on familiar epistemological or ontological concerns. The key idea behind this view is that typical mathematical hypotheses are indeterminate because they are relevantly similar to CH. (shrink)

In “Mathematical Truth,” Paul Benacerraf presented an epistemological problem for mathematical realism.

In his précis of a recent book, Richard Joyce writes, “My contention…is that…any epistemological benefit-of-the-doubt that might have been extended to moral beliefs…will be neutralized by the availability of an empirically confirmed moral genealogy that nowhere…presupposes their truth.” Such reasoning – falling under the heading “Genealogical Debunking Arguments” – is now commonplace. But how might “the availability of an empirically confirmed moral genealogy that nowhere… presupposes” the truth of our moral beliefs “neutralize” whatever “epistemological benefit-of-the-doubt that might have been extended (...) to” them? In this article, I argue that there appears to be no satisfactory answer to this question. The problem is quite general, applying to all arguments with the structure of Genealogical Debunking Arguments aimed at realism about a domain meeting two conditions. The Benacerraf-Field Challenge for mathematical realism affords an important special case. (shrink)

Some researchers and autistic activists have recently suggested that because some ‘autism-related’ behavioural atypicalities have a function or purpose they may be desirable rather than undesirable. Examples of such behavioural atypicalities include hand-flapping, repeatedly ordering objects (e.g., toys) in rows, and profoundly restricted routines. A common view, as represented in the Diagnostic and Statistical Manual of Mental Disorders (DSM) IV-TR (APA, 2000), is that many of these behaviours lack adaptive function or purpose, interfere with learning, and constitute the non-social behavioural (...) dysfunctions of those disorders making up the Autism Spectrum. As the DSM IV-TR continues to be the reference source of choice for professionals working with individuals with psychiatric difficulties, its characterization of the Autism Spectrum holds significant sway. We will suggest Extended Mind and Enactive Cognition Theories, which theorize that mind (or cognition) is embodied and environmentally embedded, as coherent conceptual and theoretical spaces within which to investigate the possibility that certain repetitive behaviours exhibited by autistics possess functions or purposes that make them desirable. As lenses through which to re-examine ‘autism-related’ behavioral atypicalities, these theories not only open up explanatory possibilities underdeveloped in the research literature, but also cohere with how some autistics describe their own experience. Our position navigates a middle way between the view of autism as understood in terms of impairment, deficit and dysfunction and one that seeks to de-pathologize the Spectrum. In so doing we seek to contribute to a continuing dialogue between researchers, clinicians and self- or parent advocates. (shrink)

I discuss methodology in epistemology. I argue that settling the facts, even the epistemic facts, fails to settle the questions of intellectual policy at the center of our epistemic lives. An upshot is that the standard methodology of analyzing concepts like knowledge, justification, rationality, and so on is misconceived. More generally, any epistemic method that seeks to issue in intellectual policy by settling the facts, whether by way of abductive theorizing or empirical investigation, no matter how reliable, is inapt. The (...) argument is a radicalization of Moore’s Open Question Argument. I conclude by considering the ramifications of this conclusion for the debate surrounding “Modal Security”, a proposed necessary condition on undermining defeat. (shrink)

Logical monism is the view that there is ‘One True Logic’. This is the default position, against which pluralists react. If there were not ‘One True Logic’, it is hard to see how there could be one true theory of anything. A theory is closed under a logic! But what is logical monism? In this article, I consider semantic, logical, modal, scientific, and metaphysical proposals. I argue that, on no ‘factualist’ analysis (according to which ‘there is One True Logic’ expresses (...) a factual claim, rather than an attitude like approval), does the doctrine have both metaphysical and methodological import. Metaphysically, logics abound. Methodologically, what to infer from what is not settled by the facts, even the normative ones. I conclude that the only interesting sense in which there could be One True Logic is noncognitive. The same may be true of monism about normative areas, like moral, epistemic, and prudential ones, generally. (shrink)

Not only did Paracelsus (1493-1541) censure the logic of the Aristotelians, but also their "Godless" approach to questioning nature. He declared that Aristotle was “a heathen whose work had rightly been condemned repeatedly in church councils." In this essay I elucidate some of the more salient features of Paracelsus’s "epistemology," and draw parallels between his notion of experientia (Erfahrung) and that of Hans-Georg Gadamer. I also discuss Paracelsus’s educational metaphor, his creation myth, and the mysterious doctrine of signatures en route (...) to uncovering his peculiar understanding of the relationship between theory, practice, and experience. (shrink)

The practice of Emergency Management in Michigan raises anew the question of whose knowledge matters to whom and for what reasons, against the background of what projects, challenges, and systemic imperatives. In this paper, I offer a historical overview of state intervention laws across the United States, focusing specifically on Michigan’s Emergency Manager laws. I draw on recent analyses of these laws to develop an account of a phenomenon that I call epistemic redlining, which, I suggest, is a form of (...) group-based credibility discounting not readily countenanced by existing, ‘culprit-based’ accounts of epistemic injustice. I argue that epistemic redlining plays a crucial role in ongoing projects of racialized subordination and dispossession in Michigan, and that such discounting tends to have structural causes that can be difficult to identify and uproot. Contrary to the general thrust of recent work on the topic, I argue that epistemic redlining ought to be understood as a form of epistemic injustice. (shrink)

In this paper I explore Phyllis Rooney’s 2003 chapter, “Feminist Epistemology and Naturalized Epistemology: An Uneasy Alliance,” taking guidance from her critique of naturalized epistemology in pursuing my own analysis of another uneasy alliance: that between feminist epistemology and social epistemology. Investigating some of the background assumptions at work in prominent conceptions of social epistemology, I consider recent analyses of "epistemic bubbles" to ask how closely such analyses are aligned with ongoing research in feminist epistemology. I argue that critical feminist (...) insights in political philosophy are called for here, especially those that focus on multiple politically salient relationships and also emphasize practices of personal transformation as inseparably bound up with broader movements for social transformation. Insofar as feminist epistemology continues to carry another world in its heart, I argue that it will continue to rest uneasily with any effort to align it with—let alone subsume it within—the still emerging field of social epistemology. (shrink)

How do axioms, or first principles, in ethics compare to those in mathematics? In this companion piece to G.C. Field's 1931 "On the Role of Definition in Ethics", I argue that there are similarities between the cases. However, these are premised on an assumption which can be questioned, and which highlights the peculiarity of normative inquiry.

I discuss the structure of genealogical debunking arguments. I argue that they undermine our mathematical beliefs if they undermine our moral beliefs. The contrary appearance stems from a confusion of arithmetic truths with (first-order) logical truths, or from a confusion of reliability with justification. I conclude with a discussion of the cogency of debunking arguments, in light of the above. Their cogency depends on whether information can undermine all of our beliefs of a kind, F, without giving us direct reason (...) to doubt that our F-beliefs are modally secure. (shrink)

When confronted with especially complex ecological and social problems such as climate change, how are we to think about responsibility for collective inaction? Social and political philosophers have begun to consider the complexities of acting collectively with a view to creating more just and sustainable societies. Some have recently turned their attention to the question of whether more or less formally organized groups can ever be held morally responsible for not acting collectively, or else for not organizing themselves into groups (...) capable of so doing. In this paper I argue that several questionable assumptions have shaped the character and scope of inquiry to this point, precluding us from grappling with a range of important questions concerning the epistemic dimensions of collective inaction. I offer an overview of recent conversation concerning collective inaction, advance a critique of the picture of responsibility that has emerged from this conversation, and propose an alternative approach to th... (shrink)

In his influential book, The Nature of Morality, Gilbert Harman writes: “In explaining the observations that support a physical theory, scientists typically appeal to mathematical principles. On the other hand, one never seems to need to appeal in this way to moral principles.” What is the epistemological relevance of this contrast, if genuine? This chapter argues that ethicists and philosophers of mathematics have misunderstood it. They have confused what the chapter calls the justificatory challenge for realism about an area, D—the (...) challenge to justify our D-beliefs—with the reliability challenge for D-realism—the challenge to explain the reliability of our D-beliefs. Harman’s contrast is relevant to the first, but not, evidently, to the second. One upshot of the discussion is that genealogical debunking arguments are fallacious. Another is that indispensability considerations cannot answer the Benacerraf–Field challenge for mathematical realism. (shrink)

The evidence is overwhelming that members of particularly wealthy and industry-owning segments of Western societies have much larger carbon footprints than most other humans, and thereby contribute far more than their “fair share” to the enormous problem of climate change. Nonetheless, in this paper we shall counsel against a strategy focused primarily on blaming and shaming and propose, instead, a change in the ethical conversation about climate change. We recommend a shift in the ethical framework from a focus on the (...) role of individual agents and a conversation about guilt; in its place, we propose a relational approach to public health ethics that is centered around the idea of relational solidarity. We begin by briefly reviewing the most common—and woefully inadequate—approach in the West to reducing emissions and responding to the health-related impacts of climate change. We then go on to propose a relational approach to public health ethics as an alternative ethical framework that better fits the moral problems associated with climate change and holds promise for a more meaningful response. (shrink)

Set-theoretic pluralism is an increasingly influential position in the philosophy of set theory (Balaguer [1998], Linksy and Zalta [1995], Hamkins [2012]). There is considerable room for debate about how best to formulate set-theoretic pluralism, and even about whether the view is coherent. But there is widespread agreement as to what there is to recommend the view (given that it can be formulated coherently). Unlike set-theoretic universalism, set-theoretic pluralism affords an answer to Benacerraf’s epistemological challenge. The purpose of this paper is (...) to determine what Benacerraf’s challenge could be such that this view is warranted. I argue that it could not be any of the challenges with which it has been traditionally identified by its advocates, like of Benacerraf and Field. Not only are none of the challenges easier for the pluralist to meet. None satisfies a key constraint that has been placed on Benacerraf’s challenge. However, I argue that Benacerraf’s challenge could be the challenge to show that our set-theoretic beliefs are safe – i.e., to show that we could not have easily had false ones. Whether the pluralist is, in fact, better positioned to show that our set-theoretic beliefs are safe turns on a broadly empirical conjecture which is outstanding. If this conjecture proves to be false, then it is unclear what the epistemological argument for set-theoretic pluralism is supposed to be. (shrink)

The motivating question of this paper is: ‘How are our beliefs in the theorems of mathematics justified?’ This is distinguished from the question ‘How are our mathematical beliefs reliably true?’ We examine an influential answer, outlined by Russell, championed by Gödel, and developed by those searching for new axioms to settle undecidables, that our mathematical beliefs are justified by ‘intuitions’, as our scientific beliefs are justified by observations. On this view, axioms are analogous to laws of nature. They are postulated (...) to best systematize the data to be explained. We argue that there is a decisive difference between the cases. There is agreement on the data to be systematized in the scientific case that has no analog in the mathematical one. There is virtual consensus over observations, but conspicuous dispute over intuitions. In this respect, mathematics more closely resembles stereotypical philosophy. We conclude by distinguishing two ideas that have long been associated -- realism (the idea that there is an independent reality) and objectivity (the idea that in a disagreement, only one of us can be right). We argue that, while realism is true of mathematics and philosophy, these domains fail to be objective. One upshot of the discussion is that even questions of fundamental physics may fail to be objective in roughly the sense that the question, ‘Is the Parallel Postulate is true?’, understood as one of pure mathematics, fails to be. Another is a kind of pragmatism. Factual questions in mathematics, modality, logic, and evaluative areas go proxy for non-factual practical ones. -/- . (shrink)

What form must a theory of epistemic injustice take in order to successfully illuminate the epistemic dimensions of struggles that are primarily political? How can such struggles be understood as involving collective struggles for epistemic recognition and self-determination that seek to improve practices of knowledge production and make lives more liveable? In this paper, I argue that currently dominant, Fricker-inspired approaches to theorizing epistemic wrongs and remedies make it difficult, if not impossible, to understand the epistemic dimensions of historic and (...) ongoing political struggles. Recent work in the theory of recognition— particularly the work of critical, feminist, and decolonial theorists—can help to identify and correct the shortcomings of these approaches. I offer a critical appraisal of recent conversation concerning epistemic injustice, focusing on three characteristics of Frickerian frameworks that obscure the epistemic dimensions of political struggles. I propose that a theory of epistemic injustice can better illuminate the epistemic dimensions of such struggles by acknowledging and centering the agency of victims in abusive epistemic relations, by conceptualizing the harms and wrongs of epistemic injustice relationally, and by explaining epistemic injustice as rooted in the oppressive and dysfunctional epistemic norms undergirding actual communities and institutions. (shrink)

Holly Smith has done more than anyone to explore and defend the importance of usability for moral theories. In Making Morality Work, she develops a moral theory that is almost universally usable. But not quite. In this article, I argue that no moral theory is universally usable, in the sense that is most immediately relevant to action, even by agents who know all the normative facts. There is no moral theory knowledge of which suffices to settle deliberation about what to (...) do. However, this is unsurprising if the question of what to do is not a question of fact. One upshot of the discussion is that the search for a universally usable moral theory is misconceived. Another is that, contra Smith (341), agents who are radically uncertain need not lack autonomy. (shrink)

One branch of bioethics assumes that mainly agents of the state are responsible for public health. Following Susan Sherwin’s relational ethics, we suggest moving away from a “state-centered” approach toward a more thoroughly relational approach. Indeed, certain agents must be reconstituted in and through shifting relations with others, complicating discussions of responsibility for public health. Drawing on two case studies—the health politics and activism of the Black Panther Party and the work of the Common Ground Collective in post-Katrina New Orleans—we (...) argue for the need to attend more carefully to the limitations of states and state-driven public health programs. (shrink)

I this article, I introduce the notion of pluralism about an area, and use it to argue that the questions at the center of our normative lives are not settled by the facts -- even the normative facts. One upshot of the discussion is that the concepts of realism and objectivity, which are widely identified, are actually in tension. Another is that the concept of objectivity, not realism, should take center stage.

Post-mortem reproduction is a complex and contested matter attracting attention from a diverse group of scholars and resulting in various responses from a range of countries. Vietnam has been reluctant to deal directly with this matter and has, accordingly, permitted post-mortem reproduction implicitly. First, by analysing Vietnam’s post-mortem reproduction cases, this paper reflects on the manner in which Vietnamese authorities have handled each case in the context of the contemporary legal framework, and it reveals the moral questions arising therefrom. The (...) article then offers an account of Vietnamese social norms as an explanation for the tendency to conduct post-mortem reproduction. In arguing that a deeper and more thorough examination of the moral and ethical reasoning is required, the paper advocates in favour of supportive post-mortem reproduction regulation. In doing so, the paper seeks to reconcile the Vietnamese legal framework and post-mortem reproduction experiences of other countries. The article concludes that Vietnam and countries sharing the similar cultural traits should permit post-mortem reproduction explicitly. This would require full engagement with the ethical and legal issues arising, and careful promulgation of regulations and guidelines based on comparative experiences of a range of countries in handling this matter. (shrink)

In this chapter I offer a critique of the received way of thinking about responsibility for collective inaction and propose an alternative approach that takes as its point of departure the epistemic agency exhibited by people navigating impossible situations together. One such situation is becoming increasingly common in the context of climate change: so-called “natural” disasters wreaking havoc on communities—flooding homes, collapsing infrastructures, and straining the capacities of existing organizations to safeguard lives and livelihoods. What happens when philosophical reflection begins (...) here—in places where the institutions and practices that have emerged over the last century seem incapable of addressing the problems communities face now, and where people find themselves turning to one another for the sake of their own survival? (shrink)

For several years the authors have been working in Detroit with grassroots coalitions resisting Emergency Management. In this essay, we focus on how community groups in Detroit and Flint advanced common struggles for clean, safe, affordable water as a human right, particularly during the period of 2014 to 2016. We explore how, through a series of direct interventions – including public meetings and international gatherings, independent journalism and social media, community-based research projects, and citizen-led policy initiatives – these groups contributed (...) to challenging neoliberal governance, to undermining the legitimacy of state officials and their policies, and to shifting public consciousness around the human right to water. (shrink)

The Fifty-Year Rebellion invites us to consider Detroit’s recent history as both epitomizing and shaping national trends. But it’s not the kind of invitation we’ve all grown used to...

I discuss Benacerraf's epistemological challenge for realism about areas like mathematics, metalogic, and modality, and describe the pluralist response to it. I explain why normative pluralism is peculiarly unsatisfactory, and use this explanation to formulate a radicalization of Moore's Open Question Argument. According to the argument, the facts -- even the normative facts -- fail to settle the practical questions at the center of our normative lives. One lesson is that the concepts of realism and objectivity, which are widely identified, (...) are actually in tension. (shrink)

Addicts are often portrayed as compelled by their addiction and thus as a paradigm of unfree action and mitigated blame. This chapter argues that our best scientific theories of addiction reveal that, psychologically, addicts are not categorically different from non-addicts. There is no pairing of contemporary accounts of addiction and of prominent theories of moral responsibility that can justify our intuitions about the mitigation of addicts but not non-addicts. Two conclusions are advanced. First, we should either treat addicts as we (...) normally treat non-addicts (as fully culpable) or embrace the skeptical conclusion that everyone is less responsible than we thought—perhaps not responsible at all. Second, we should be doubtful that theorizing about responsibility will be advanced by focusing on particular kinds of psychopathologies. (shrink)

Over the past five years the authors have been working in Detroit with grassroots coalitions resisting emergency management. In this essay, we explore how community groups in Detroit and Flint have advanced common struggles for clean, safe, affordable water as a human right, offering an account of activism that has directly confronted neoliberalism across the state. We analyze how solidarity has been forged through community organizing, interventions into mainstream media portrayals of the water crises, and the articulation of counternarratives that (...) center the experiences, needs, and collective power of those most directly affected. While our rootedness in Detroit leads us to focus primarily on the experiences of activists based there rather than in Flint, we insist throughout that the experiences, resistance, and aspirations of these communities are best understood as interconnected and mutually empowering. (shrink)

In this paper I engage interdisciplinary conversation on inaction as the dominant response to climate change, and develop an analysis of the specific phenomenon of complacency through a critical-feminist lens. I suggest that Chris Cuomo's discussion of the “insufficiency” problem and Susan Sherwin's call for a “public ethics” jointly point toward particularly promising harm-reduction strategies. I draw upon and extend their work by arguing that extant philosophical accounts of complacency are inadequate to the task of sorting out what it means (...) to be complacent on climate change. I offer a sketch for an alternative account, which I take to be a start in the direction of mapping out a diverse array of “motivational vices” that need to be named, grappled with, and remedied. (shrink)

Xuan-Hung Doan, Phuong-Tram T. Nguyen, Viet-Phuong La, Hong-Kong T. Nguyen (2019). Chapter 5. Researchers who lead the trends. In Quan-Hoang Vuong, Trung Tran (Eds.), The Vietnamese Social Sciences at a Fork in the Road (pp. 98–120). Warsaw, Poland: De Gruyter. DOI:10.2478/9783110686081-010 -/- Online ISBN: 9783110686081 © 2019 Sciendo.

My commentary deals with the fourth chapter of Against Purity, entitled “Consuming Suffering,” where Shotwell invites us to imagine what an alternative to ethical individualism might look like in practice. I am particularly interested in the analogy she develops to help pull us into the frame of what she calls a “distributed” or “social” approach to ethics. I will argue that grappling with this analogy can help illuminate three challenges confronting those of us seeking a genuine alternative to ethical individualism: (...) first, that of recognizing that and how certain organizational forms work to entrench an individualistic orientation to the world; second, that of acknowledging the inadequacy of alternatives to individualism that are merely formal in character; and third, that of avoiding the creation of organizational forms that foster purism at the collective level. (shrink)

In gloomy and despairing times, we who work for liberation generate light and joy. We experience this every time we work together to defend our communities, when we fight to win collective victories, when we build something new. Much of the time these experiences are in marches and meetings – really important spaces for movement work. But here we want to amplify the usefulness of collective study, and share some thoughts about why Harsha Walia’s new book Border and Rule would (...) be a great place to start if you might like to try a political kind of book club. (shrink)

The global water crisis is being exacerbated by climate change, even in the United States. Recycled water is a feasible alternative to alleviate the water shortage, but it is constrained by humans’ perceptions. The current study examines how residents’ water scarcity awareness and climate change belief influence their willingness to use recycled water directly and indirectly. Bayesian Mindsponge Framework (BMF) analytics was employed on a dataset of 1831 residents in Albuquerque, New Mexico, an arid inland region in the US. We (...) discovered that residents’ willingness to use direct recycled potable water is positively affected by their awareness of water scarcity, but the effect is conditional on their belief in the impacts of climate change on the water cycle. Meanwhile, the willingness to use indirect recycled potable water is influenced by water scarcity awareness, and the belief in climate change further enhances this effect. These findings implicate that fighting climate change denialism and informing the public of the water scarcity situation in the region can contribute to the effectiveness and sustainability of long-term water conservation and climate change alleviation efforts. (shrink)

Since 2013, Vietnam has implemented a plan to reform the whole education sector. However, there is little understanding on the status of educational research in Vietnam, which may lay the foundation for such plan. Thus, this research aims to analyze the whole picture of educational research from Vietnam, as seen from the Clarivate Web of Science (WOS) database: 215 publications were recorded, ranging from 1991 to 2018. These 215 publications were further analyzed from five perspectives: 1) number of publications by (...) year; 2) research fields and levels of education; 3) top institutions with the highest number of publications; 4) international collaboration; and 5) quality. Some of the most notable results are: 1) the educational sciences in Vietnam have been still under-developed until recently; 2) among different research topics research among educational sciences, some (e.g., Vocational Education and Training or Early Childhood Education) seemed to be overlooked whereas others (e.g., Higher Education and Teaching and Learning) seemed to receive more attention from educational scholars; 3) all the most major education – specialized universities did not appear among the top five institutions with highest number of publications; 4) Australia, Thailand, the USA, New Zealand and China were the countries with the highest number of co-publications with Vietnamese researchers; and 5) The majority of publications belonged to low-ranked journals. Implications would be withdrawn for Vietnamese policymakers, education leaders, educational researchers and teachers in order to adjust their policies and/or action plans; thus, enhancing the performance and impacts of educational research in the future. (shrink)

This paper examines the differences in the impact of ownership types and economic sectors on the business efficiency of 4,733 enterprises in Vietnam by the year of 2015. By the method of analysis of variance (ANOVA), it is shown that while types of ownership, foreign, state and private ownership, have a significant and different impact on the performance of businesses, the difference in economic sectors does not affect the enterprise efficiency. In addition, when testing simultaneous effect of these factors, some (...) findings are as follows: private-owned enterprises’ efficiency in the manufacturing and service sectors is better than those in agriculture, forestry and fishing sector; conversely, foreign invested enterprises operating in agriculture, forestry and fishing sector own better performance than theirs in manufacturing and service sectors; state-owned enterprises in manufacturing and service sectors is very less efficient than theirs in agriculture, forestry and fishing sector. (shrink)

I argue that certain species of belief, such as mathematical, logical, and normative beliefs, are insulated from a form of Harman-style debunking argument whereas moral beliefs, the primary target of such arguments, are not. Harman-style arguments have been misunderstood as attempts to directly undermine our moral beliefs. They are rather best given as burden-shifting arguments, concluding that we need additional reasons to maintain our moral beliefs. If we understand them this way, then we can see why moral beliefs are vulnerable (...) to such arguments while mathematical, logical, and normative beliefs are not—the very construction of Harman-style skeptical arguments requires the truth of significant fragments of our mathematical, logical, and normative beliefs, but requires no such thing of our moral beliefs. Given this property, Harman-style skeptical arguments against logical, mathematical, and normative beliefs are self-effacing; doubting these beliefs on the basis of such arguments results in the loss of our reasons for doubt. But we can cleanly doubt the truth of morality. (shrink)

A belief one has is safe if either (i) it could not easily be false or (ii) in any nearby world in which it is false, it is not formed using the method one uses to form one’s actual belief. It seems our mathematical beliefs are safe if mathematical pluralism is true: if, loosely put, almost any consistent mathematical theory is true. It seems, after all, that in any nearby world where one’s mathematical beliefs differ from one’s actual beliefs, one (...) would believe some other true, consistent theory. Focusing on Justin Clarke-Doane’s recent discussion, I argue the thesis that mathematical beliefs are safe given pluralism faces some obstacles. I argue (i) is true of mathematical belief given pluralism only if we deny plausible claims about the interpretation of non-pluralists who many of us could easily be. Unless strong metasemantic theses are true, it is plausible many of us could easily deny or refuse to believe a consistent and true mathematical theory we actually believe. Since philosophical arguments and controversies permeate the methodology of foundational mathematics, I argue we cannot confidently distinguish the methods we use in mathematics between worlds, thus raising doubts about (ii). (shrink)

It’s sometimes suggested that we can (in a sense) settle the truth-value of some statements in the language of number theory by stipulation, adopting either φ or ¬φ as an additional axiom. For example, in Clarke-Doane (2020b) and a series of recent APA presentations, Clarke-Doane suggests that any Σ01 sound expansion of our current arithmetical practice would express a truth. In this paper, I’ll argue that (given a certain popular assumption about the model-theoretic representability of languages like ours) we can’t (...) know ourselves to have any such freedom. (shrink)

Humans and other animals have an evolved ability to detect discrete magnitudes in their environment. Does this observation support evolutionary debunking arguments against mathematical realism, as has been recently argued by Clarke-Doane, or does it bolster mathematical realism, as authors such as Joyce and Sinnott-Armstrong have assumed? To find out, we need to pay closer attention to the features of evolved numerical cognition. I provide a detailed examination of the functional properties of evolved numerical cognition, and propose that they prima (...) facie favor a realist account of numbers. (shrink)

Modalists think that knowledge requires forming your belief in a “modally stable” way: using a method that wouldn't easily go wrong, or using a method that wouldn't have given you this belief had it been false. Recent Modalist projects from Justin Clarke-Doane and Dan Baras defend a principle they call “Modal Security,” roughly: if evidence undermines your belief, then it must give you a reason to doubt the safety or sensitivity of your belief. Another recent Modalist project from Carlotta Pavese (...) and Bob Beddor defends “Modal Virtue Epistemology”: knowledge is a belief that is maximally modally robust across “normal” worlds. We'll offer new objections to these recent Modalist projects. We will then argue for a rival view, Explanationism: knowing something is believing it because it's true. We will show how Explanationism offers a better account of undermining defeaters than Modalism, and a better account of knowledge. (shrink)

RELAÇÃO E EFEITOS BIOQUÍMICO-NUTRICIONAIS SOBRE OS TRANSTORNOS DO CICLO ESTRAL DE VACAS -/- Emanuel Isaque Cordeiro da Silva Departamento de Agropecuária – IFPE Campus Belo Jardim [email protected] ou [email protected] WhatsApp: (82)98143-8399 -/- •__6. Transtornos do ciclo estral -/- Qualquer alteração na frequência, duração ou intensidade do ciclo estral é considerada uma perturbação do ciclo, cujas origens variam etiologicamente. As perturbações do ciclo podem originar-se em qualquer das partes do eixo hipotálamo-hipófise-ovário (FRAZER, 2005; GORDON, 1996). Pode ou não ser do tipo (...) permanente e pode depender de sua origem, momento e intensidade cursar com outras alterações reprodutivas, por exemplo uma retenção do corpo lúteo, dá lugar a prolongamento da fase lútea, altos níveis de progesterona circulante e pode, finalmente, desencadear em um cisto luteal ou em uma metrite. Entre os fatores desencadeadores da falha do ciclo estral estão os fatores de origem nutricional, dentre eles: 6.1 Minerais 6.1.1 Relação Na:K (Sódio: Potássio) A deficiência de sódio pode causar distúrbios do ciclo estral, isto porque as células animais intracelularmente possuem uma alta concentração de K e uma baixa concentração de Na, esta relação pode chegar a 10:1 ou mais, em relação ao meio externo. Com esta relação, as concentrações intracelulares estão em equilíbrio com o meio externo. A absorção e secreção de cátions pela célula para conseguir o equilíbrio é simultânea, gerada por um sistema de transporte específico chamado "bomba Na-K". Se a nível celular não existe um balanço iônico de K:Na, a maior prioridade das células tubulares do rim é a de conseguir novamente um equilíbrio, o mecanismo destas células é o da reabsorção do íon que se encontre em excesso de água, diminuindo a quantidade deste no líquido para manter as funções em equilíbrio dinâmico. Os desequilíbrios não compensados a nível celular ou renal, levam a alterações na condutividade nervosa por alteração da bomba de transmissão elétrica. O ciclo estral é alterado por diminuir a expressividade dos sinais comportamentais de estro, que são produzidos por concentrações crescentes de estrogênio mas com alta necessidade de adequação nervosa para a exposição corporal do cio e a aceitação da monta. O potássio, em particular, desempenha um papel fundamental como coator em certas interações enzimáticas, incluindo a transferência de energia, a síntese de proteínas e o metabolismo de hidratos de carbono, em especial nos sistemas em que o ADP está envolvido, as hexoquinases e a anidrase carbônica. O sódio, por sua vez, é o principal cátion extracelular, regula o equilíbrio hídrico no organismo e a mecânica de fluidos, desta forma regula a pressão osmótica e a troca aquosa nos tecidos. Devido a esta função, um dos fatores importantes do fluxo Na:K é o rim, que é controlado pela aldosterona, a principal hormona reguladora da absorção de sódio e excreção de potássio. Qualquer desequilíbrio na relação Na:K, afetará o ciclo estral, de maneira direta e indireta, através da alteração na síntese de proteínas e da perda da regulação hídrica, fator importante pelas secreções que devem acompanhar as manifestações de cio/estro. 6.1.2 Relação Cobalto (Co) A deficiência de cobalto gera um efeito biológico determinado pela sua presença na molécula da vitamina B12, a qual regula a hematopoese (Ativa a síntese de protoporfirina) e afeta o metabolismo do nitrogênio e dos carboidratos. A vitamina B12 atua como uma coenzima da transmetilação (síntese do glutamato mutase, metilmalonil-CoA-Mutase, diol-dehidratase e redução dos ribonucleótidos a desoxirribonucleótidos, isomerização da a-lisina, etc.). Especialmente em ruminantes, a reação mutase da metilmalonina-CoA está relacionada com o metabolismo do ácido propiônico e, portanto, com a síntese de glicose e o equilíbrio energético. O cobalto também está envolvido na carboxilação da propionil-CoA à metilmalonil-CoA e na isomerização deste último para succinil-CoA. O metabolismo do ácido propiônico ocorre no fígado e é reduzido pelo fato do metilmalonil não poder ser convertido em succinil-CoA, impedindo a sua passagem para oxalacetato e glicose, gerando uma relação inversa entre os níveis de energia e proteína; causando uma diminuição de GnRH que afeta negativamente a liberação de LH que, por sua vez, cria um aumento na FSH. Isso produz uma anulação da ovulação e, consequentemente, ausência de um ciclo estral verdadeiro. Vale reforçar que, para prevenção da deficiência do cobalto, o criador pode optar pelo fornecimento de volumosos que dispõem de quantidades de cobalto que suprem as exigências dos animais, ou pela inserção de sais de cobalto à mistura da ração, sempre no intervalo sugerido de 0,07 e 0,11 mg/kg para cada animal, suprindo a necessidade do mesmo e garantindo assim a prevenção dos transtornos do ciclo estral ou outras afecções do sistema reprodutivo. 6.1.3 Relação Cobre (Cu) e Molibdênio (Mo) A deficiência de cobre gera, indiretamente, molibdênio, durante esse processo, tanto o macho como a fêmea são inférteis ou sub-férteis, mas, em geral, os transtornos surgem não por molibdeniose mas por hipocuprose condicionada por excesso de molibdênio nas pastagens e pelos sulfatos presentes na água de bebida (BREM, 2016). Isso leva à formação de tiomolibdato no rúmen, que por sua vez combina com o cobre para formar tiomolibdato de cobre, sal muito insolúvel. O tiomolibdato presente, formado em excesso e que não encontra cobre suficiente, contribuirá para produzir a diarreia, limitando ainda mais a absorção de cobre. A interferência mais importante do molibdênio ocorre no processo metabólico do cobre, interferindo sua atividade enzimática. O molibdênio atua sobre o complexo sulfeto-oxidase hepático. A enzima que está envolvida na oxidação de metabolitos sulfurados, reduz a sua atividade na presença de altos teores de molibdênio, especialmente quando a quantidade de cobre é baixa. Daqui resulta a formação de sulfureto de cobre, muito insolúvel e, portanto, pouco ou nada utilizável pelas células e/ou tecidos (QUIROZ-ROCHA & BOUDA, 2001). O excesso de molibdênio nas pastagens ou na água de bebida reduz a quantidade de cobre no fígado, mas para uma dada dose de molibdênio, esta redução é diretamente proporcional ao aumento dos sulfatos na ingestão, porque só na presença de sulfatos o molibdênio exerce sua ação limitante. O melhor modo de tratar o molibdênio e a ação dos sulfatos sobre o cobre, é aumentar a quantidade de cobre disponível pelos animais, seja por via bucal ou parenteral. Desta forma, há aumentos na cupremia e no ganho de peso. É conveniente, para o efeito, efetuar um controle dos resultados mediante a observação clínica, pesagem dos animais e análise de cobre no sangue. Isso permitirá estabelecer as doses ideais e adequadas para cada estabelecimento e efetuar um estudo econômico da suplementação (BAVERA, 2002). Como já foi tratado o requerimento do cobre para evitar os problemas reprodutivos das vacas, falemos do molibdênio (Mo). O Mo é um elemento primordial para bovinos leiteiros, uma vez que é componente de uma enzima presente no leite (xantina oxidasse). A deficiência de Mo a nível prático não foi relatada, porém casos podem acontecer. Para ovinos, que é uma espécie ruminante, a concentração exigida pelo animal em Mo presente na MS é de 5 a 10 mg/kg, porém deve levar em consideração a relação crítica entre o Mo e o Cu que deve ser no máximo 20 e nunca superior. O nível crítico de toxidade de Mo nos alimentos volumosos (forrageiras, gramíneas e leguminosas) não pode ultrapassar os 6% por kg de MS. Através de todos esses cuidados, o criador poderá obter sucesso tanto na prevenção contra os distúrbios do ciclo estral das vacas, quanto de outras complicações como toxidade, desnutrição, etc. 6.2 Relação energia:proteína Em relação ao aumento do consumo de proteína crua ou de deficiência de energia, aumenta-se a quantidade de ureia no sangue e produz-se uma toxicidade tecidular, afetando o endométrio e diminuindo a produção de prostaglandinas, que são as encarregadas de manter o corpo lúteo, caso não se mantenha acaba provocando um ciclo estral longo. A situação pode ser explicada a nível do eixo hipotálamo-hipófise, no qual os baixos níveis de glicose inibem a secreção de GnRH e resultam na diminuição da pulsatilidade da LH, seja por ação direta ou mediada através das ß-endorfinas. Outro fator que afeta o crescimento folicular é a nutrição, especificamente a perda da condição corporal, quando o animal não se alimenta direito ou quando se alimenta não tem uma condição balanceada que supra suas exigências nutricionais e que tenha um aceitável ganho de peso diário (GPD), acaba perdendo massa muscular ou de gordura, em outras palavras altera-se a condição corporal do mesmo, e se a perda for de 22 a 24 % de peso corporal (PC), os animais que perdem essa condição entram em anestro o que acaba tornando um animal inviável para a reprodução e também para o abate, uma vez que encontra-se fora do peso ideal. Tanto as proteínas quanto a energia foram tratados em trabalhos anteriores, porém nunca é tarde para salientar que ambas devem ser fornecidas em qualidade e quantidade que consiga favorecer ao desenvolvimento do animal e aos mecanismos fisiológicos do mesmo. 6.3 Fito-toxidade Finalmente, um fator adicional que induz a alteração da ciclicidade estral são os fitoestrógenos, plantas com altos teores de isoflavonas que possuem, no organismo animal, uma ação estrogênica. Os fitoestrógenos estão amplamente difundidos, nos trevos, alfafa, milho e nas pastagens de cultivo intensivo. Os fitoestrogênios são diferentes dos estrogênios produzidos pelo animal, mas a sua ação é idêntica nos receptores do trato reprodutivo; o seu metabolismo e excreção é diferente (por exemplo, desmetilização) e a sua excreção renal através dos glicoronosidos, assim mesmo a formação de ésteres sulfatos no tecido hepático é menor, acumulando-se em circulação e alterando a duração da fase estrogênica do ciclo, isso leva à ninfomania das vacas e com ela a perda da função reprodutiva. Deve-se estar atento ao pasto que se cultiva e ao solo em que se implanta o pasto, uma vez que o solo pode ter excessos de minerais prejudiciais ao animal e que o coloque em uma situação de toxidade, já que a planta absorve do solo o excesso e da planta vai para o animal por meio direto ou pela silagem. Um exemplo é o teor de molibdênio na planta que não pode ser maior que 6%, se for ocorrerá inúmeras transformações fisiológicas maléficas ao animal, que acabará sendo descartado do objetivo que seria a reprodução na fazenda. -/- Apoio -/- Realização -/- REFERÊNCIAS BIBLIOGRÁFICAS BAVERA, Guillermo Alejandro. Aguas y aguadas para el ganado. Rio Cuarto: Inter-Medica Editorial, 2009. BERCHIELLI, Telma Teresinha; PIRES, Alexandre Vaz; OLIVEIRA, SG de. Nutrição de ruminantes. Jaboticabal: funep, 2006. BINDARI, Yugal Raj et al. Effects of nutrition on reproduction-A review. Adv. Appl. Sci. Res, v. 4, n. 1, p. 421-429, 2013. BOLAND, M. P. Efectos nutricionales en la reproducción del ganado. XXXI Jornadas Uruguayas de Buiatría, 2003. BREM, J. J. et al. Alteraciones del ciclo estral provocadas por un alto ingreso de molibdeno en vaquillonas Brangus y respuesta a la suplementación con cobre. Revista Veterinaria, v. 12, n. 1 y 2, p. 28-33, 2016. DEHNING, R. Interrelaciones entre nutrición y fertilidad. In: Curso Manejo de la Fertilidad Bovina18-23 May 1987Medellín (Colombia). CICADEP, Bogotá (Colombia) Universidad de La Salle, Medellín (Colombia) Instituto Colombiano Agropecurio, Bogotá (Colombia) Sociedad Alemana de Cooperación Técnica-GTZ (Alemania), 1987. DE LUCA, Leonardo J. Nutrición y fertilidad en el ganado lechero. XXXVI Jornadas Uruguayas de Buiatría, 2008. FRAZER, Grant S. Bovine theriogenology. Veterinary Clinics: Food Animal Practice, v. 21, n. 2, p. xiii-xiv, 2005. GORDON, Ian. Controlled reproduction in farm animals series. Nova Iorque: CAB International, 1996. GRAHAM, Thomas W. Trace element deficiencies in cattle. Veterinary clinics of North America: food animal practice, v. 7, n. 1, p. 153-215, 1991. GUEDES, Luciana Freitas et al. A importância do cobre, molibdênio e enxofre na alimentação de ovinos. Nucleus Animalium, v. 10, n. 2, p. 7-22, 2018. HURLEY, W. L.; DOANE, R. M. Recent developments in the roles of vitamins and minerals in reproduction. Journal of Dairy Science, v. 72, n. 3, p. 784-804, 1989. KUMAR, Sudhir et al. Importance of micro minerals in reproductive performance of livestock. Veterinary world, v. 4, n. 5, p. 230, 2011. MAAS, John. Relationship between nutrition and reproduction in beef cattle. The Veterinary Clinics of North America. Food Animal Practice, v. 3, n. 3, p. 633-646, 1987. MILLS, C. F. Cobalt deficiency and cobalt requirements of ruminants. Recent advances in animal nutrition, p. 129-141, 1981. NICODEMO, M. L. F.; SERENO, J. R. B.; AMARAL, T. B. Minerais na eficiência reprodutiva de bovinos. Embrapa Pecuária Sudeste-Documentos (INFOTECA-E), São Carlos, 2008. PASA, Camila. Relação reprodução animal e os minerais. Biodiversidade, v. 9, n. 1, 2011. QUIROZ-ROCHA, Gerardo F.; BOUDA, Jan. Fisiopatología de las deficiencias de cobre en rumiantes y su diagnóstico. Vet. Méx, v. 32, n. 4, p. 289, 2001. SHORT, Robert E.; ADAMS, D. C. Nutritional and hormonal interrelationships in beef cattle reproduction. Canadian Journal of Animal Science, v. 68, n. 1, p. 29-39, 1988. YASOTHAI, R. Importance of minerals on reproduction in dairy cattle. International Journal of Science, Environment and Technology, v. 3, n. 6, p. 2051-2057, 2014. Emanuel Isaque Cordeiro da Silva Belo Jardim, 29 de março de 2020. (shrink)

According to principles of modal security, evidence undermines a belief only when it calls into question certain purportedly important modal connections between one’s beliefs and the truth (e.g., safety or sensitivity). Justin Clarke-Doane and Dan Baras have advanced such principles with the aim of blocking evolutionary moral debunking arguments. We examine a variety of different principles of modal security, showing that some of these are too strong, failing to accommodate clear cases of undermining, while others are too weak, failing to (...) do their advertised work of blocking evolutionary moral debunking arguments. If there is a security principle that slips between the horns of this dilemma—one that is both viable and debunker-blocking—it remains to be formulated. (shrink)

There are many domains about which we think we are reliable. When there is prima facie reason to believe that there is no satisfying explanation of our reliability about a domain given our background views about the world, this generates a challenge to our reliability about the domain or to our background views. This is what is often called the reliability challenge for the domain. In previous work, I discussed the reliability challenges for logic and for deductive inference. I argued (...) for four main claims: First, there are reliability challenges for logic and for deduction. Second, these reliability challenges cannot be answered merely by providing an explanation of how it is that we have the logical beliefs and employ the deductive rules that we do. Third, we can explain our reliability about logic by appealing to our reliability about deduction. Fourth, there is a good prospect for providing an evolutionary explanation of the reliability of our deductive reasoning. In recent years, a number of arguments have appeared in the literature that can be applied against one or more of these four theses. In this paper, I respond to some of these arguments. In particular, I discuss arguments by Paul Horwich, Jack Woods, Dan Baras, Justin Clarke-Doane, and Hartry Field. (shrink)

In this article, I discuss a trivialization worry for Hartry Field’s official formulation of the access problem for mathematical realists, which was pointed out by Øystein Linnebo (and has recently been made much of by Justin Clarke-Doane). I argue that various attempted reformulations of the Benacerraf problem fail to block trivialization, but that access worriers can better defend themselves by sticking closer to Hartry Field’s initial informal characterization of the access problem in terms of (something like) general epistemic norms of (...) coincidence avoidance. (shrink)

The fourteen papers in this collection offer a variety of original contributions to the epistemology of modality. In seeking to explain how we might account for our knowledge of possibility and necessity, they raise some novel questions, develop some unfamiliar theoretical perspectives, and make some intriguing proposals. Collectively, they advance our understanding of the field. In Part I of this Introduction, I give some general background about the contemporary literature in the area, by sketching a timeline of the main tendencies (...) of the past twenty-five years or so, up to the present debates. Next, I focus on four features that largely characterize the latest literature, and the papers in the present collection in particular: (i) an endorsement of the importance of essentialism; (ii) a shift to a “metaphysics-first” approach to modal epistemology; (iii) a focus on metaphysical modality as opposed to other kinds of modality; and (iv) a preference for non-uniform modal epistemology. In Part II, I present the individual papers in the volume. These are organized around the following four chapters, based on their topic: (A) Skepticism & Deflationism; (B) Essentialism; (C) Non-Essentialist Accounts; (D) Applications. -/- LIST OF CONTRIBUTORS: Francesco Berto; Stephen Biggs & Jessica Wilson; Justin Clark-Doane; Philip Goff; Bob Hale; Frank Jackson; Mark Jago; Boris Kment; Antonella Mallozzi; Graham Priest; Gabriel Rabin; Amie Thomasson; Anand Vaidya & Michael Wallner; Jennifer Wang. -/- The volume is dedicated to the memory of Bob Hale. -/- . (shrink)

In Morality & Mathematics, Justin Clarke-Doane argues that it is hard to imagine being "a realist about, for example, the standard model of particle physics, but not about mathematics." I try to explain how that seems very possible from the perspective of a physicist. What is real is the physical world; mathematics starts from descriptions of the natural world and extrapolates from there, but that extrapolation does not imply any independent reality. -/- Submitted to an Analysis Reviews symposium on Clarke-Doane's (...) Morality & Mathematics. (shrink)

Mathematical knowledge and moral knowledge (or normative knowledge more generally) can seem intuitively puzzling in similar ways. For example, taking apparent human knowledge of either domain at face value can seem to require accepting that we benefited from some massive and mysterious coincidence. In the mathematical case, a pluralist partial response to access worries has been widely popular. In this paper, I will develop and address a worry, suggested by some works in the recent literature like (Clarke-Doane, 2020 ), that (...) connections between ought facts and action prevent us from giving a similarly pluralist response to moral access worries. (shrink)

RELAÇÃO E EFEITOS BIOQUÍMICO-NUTRICIONAIS SOBRE AS ALTERAÇÕES DO CORPO LÚTEO EM VACAS -/- Emanuel Isaque Cordeiro da Silva Departamento de Agropecuária – IFPE Campus Belo Jardim [email protected] ou [email protected] WhatsApp: (82)98143-8399 -/- •__7. ALTERAÇÕES DO CORPO LÚTEO -/- A estrutura funcional desenvolve-se a partir da cavidade folicular após a ovulação. O corpo lúteo é constituído pelas células da teca interna (pequenas e ativas na primeira fase do seu desenvolvimento) e células da granulosa (grandes e ativas na segunda metade do seu (...) desenvolvimento). As principais características de cada tipo de célula podem resumir-se da seguinte forma: As células pequenas são mais sensíveis à ação da LH porque possui uma quantidade maior de receptores biologicamente ativos para esta hormona e a resposta é mediada pelo sistema AMPc-adelinato ciclase. As grandes células lúteas têm menos receptores para a LH (a maior quantidade são para a PGF2α e a PGE2), e são as responsáveis pela produção da oxitocina luteal (BAH, et al. 2006; CAMPO, 2003). Contrariamente às pequenas células lúteas, a produção de progesterona (P4) é parcialmente controlada pelo sistema Ca+2 - Fosfatil inositol-quinase C (CAMPO, 2003). A regulação da função do corpo lúteo é um mecanismo complexo. Nela intervêm fatores tróficos e líticos que estão presentes em forma simultânea durante todo o ciclo estral, e portanto a estimulação ou inibição da síntese e secreção de P4 depende do balanço entre estes fatores. (CAMPO, 2003). Dentro dos fatores tróficos, os nutrientes desempenham um papel relevante sobre a luteólise e as funções luteotrópicas, entre estas pode-se citar a ação das seguintes: -/- 7.1 Vitaminas Deficiência em betacarotenos. Vitamina A é um termo genérico que designa qualquer composto com atividade de retinol, o trans-retinol, é o composto base, sua forma aldeído e ácido são chamados de retinol e ácido retinóico, respectivamente. Por outro lado, a forma ativa da Vitamina A participa no mecanismo da visão, como 11-cis-retinal. Adicionalmente, o betacaroteno, considerado uma provitamina A é a única forma em que esta encontra nas plantas. Em sentido nutricional, a família da Vitamina A compreende todos os compostos que possuem atividade de retinol, incluindo cerca de cinquenta carotenoides que possuem atividade de provitamina A, aceitando-se que o mais ativo é o trans-betacaroteno (TORRES, et al. 2002). As vitaminas que são necessárias para o crescimento e a produção, também são essenciais para a reprodução. As recomendações atuais de vitamina A são de 75.000 UI/dia durante a lactação e 80.000 UI/dia (nota: 1 mg de Vitamina A = 400 UI) durante o período seco nas vacas leiteiras. A suplementação com vitamina A tem pouco risco de toxicidade, enquanto a sua deficiência pode retardar o aparecimento do primeiro cio/estro, induzir cios/estros silenciosos, aumentar o número de quistos ováricos, reduzir os índices de concepção, causar abortos, mortes embrionárias e ocasionar o nascimento de bezerros debilitados e fracos, uma vez que não irão nascer com os índices e requerimentos ideais de nutrientes passados da mãe para o feto pela placenta, e que, já que a mãe possui deficiência nutricional, o colostro não terá o efeito completo para passar a imunidade essencial ao neonato. Embora os mecanismos de ação não sejam claros, foram notificadas maiores secreções de esteroides ováricos quando as concentrações de β-carotenos no fluido folicular foram elevadas; logo, foram observadas maiores concentrações elevadas de β- estradiol e vitamina A nos folículos que terminaram em ovulação do que naqueles que terminaram em atresia. Para evitar as perdas reprodutivas por deficiência de vitamina A, pode-se optar pela administração oral ou injetável desta ao animal, mediante dois métodos: o primeiro consiste em adicionar 1 a 2,5 kg de premix vitamínico em 1 tonelada de grãos o que supre de 4 a 6.000 UI o que é desejável; o segundo é a administração via injetável em quantidades vide bula do fármaco. 7.2 Minerais O excesso de fósforo é absorvido principalmente no intestino delgado dos mamíferos através de um mecanismo de transporte ativo dependente do sódio, que é estimulado pela pró-hormona 1,25- hidroxivitamina D3. Os ruminantes são capazes de absorver o fósforo dietético em proporção direta às quantidades presentes na ração. Estima-se que aproximadamente 1% do corpo animal é composto de fósforo, do qual 85% está presente nos dentes e no tecido ósseo. Os tecidos moles são capazes de conter entre 0,15-0,20% de fósforo sob a forma de fosfoproteínas, nucleoproteínas, fosfolipídios, fosfato creatinina, adenosintrifosfato, glicose-6-fosfato, etc. Ao nível do plasma sanguíneo, o fósforo apresenta valores de 12,09 mg/dl. Os valores plasmáticos de fósforo são regulados principalmente pelo rim, sendo observado um aumento na excreção urinária do elemento inorgânico quando este excede a capacidade de transporte (REBOLLAR & MATEOS, 1999). O fósforo faz parte dos fosfolipídios, que são importantes no transporte de lipídios e seu metabolismo, como componente das membranas celulares. O fosfato faz parte do RNA e do DNA, componentes celulares vitais, e são essenciais para a síntese proteica. O fosfato faz parte de sistemas enzimáticos como a cocarboxilase e NAD, portanto está envolvido em todos os processos de síntese e regulação energética, dado que o corpo lúteo requer altas quantidades de energia para a síntese celular e hormonal, um excesso de fósforo pode bloquear a capacidade renal da sua regulação gerando um desequilíbrio catiônico que descompensa a relação Na:K, já que deverão ser excretados íons fosfato para regular o equilíbrio ácido-básico, desta forma, os processos celulares em tecidos de alta sensibilidade como o ovário serão afetados em sua função. A situação para prevenção de problemas relacionados ao fósforo (P) já foi tratada em assuntos anteriores, porém, sempre vale frisar para o leitor fiel que me lê que as exigências de P presentes na matéria seca (MS) variam entre 0,17 e 0,59% de P por kg/MS para bovinos de corte e em 0,32 a 0,44% por kg/MS para o gado leiteiro. Dessa forma, dados obtidos por pesquisas, ditam que para a mantença de uma vaca ou quaisquer outra categoria bovina o ideal é o consumo de 1.43 g/100 kg de peso vivo (PV), garantindo assim a prevenção de possíveis afecções reprodutivas como as alterações do corpo lúteo. Gramíneas, forragens, leguminosas e os concentrados fornecem muito bem os requerimentos de fósforo para os animais, todavia deve-se estar atento as relações e dependências do P com outros elementos como o Ca e a relação Na:K (10-15:1 idealmente). 7.3 Compostos estrogênicos Os fitoestrogênios afetam repetidamente a estabilidade do corpo lúteo. Os compostos estrogênicos encontrados principalmente em leguminosas pertencem principalmente a três grupos: isoflavanos, isoflavonas, presentes no gênero Trifolium e praticamente restritos às leguminosas, e cumestanos, que foram estudados na alfafa (Medicago sativa) e na Melilotus alba. Todas as isoflavonas sofrem algum grau de transformação no rúmen, sendo o Isoflavonoide formononetina, na realidade um pró-estrógeno, o único que se ativa no ecossistema ruminal ao ser convertido em equol, enquanto que as demais são degradadas a produtos inativos (RAMOS, et al. 1998). Por fim, a alta concentração no sangue do equol retarda a retroalimentação sobre a hipófise mediante a qual se reduzem os níveis de FSH para dar lugar à onda ovulatória de LH, se esta não ocorrer, o corpo lúteo obviamente não se formará. O conhecimento acerca dos estrogênios na alimentação animal é defasado nos livros sobre o tema, no entanto, o criador pode ficar tranquilo no que tange o tema na prática da sua fazenda e dos seus animais, uma vez que tal elemento é muito bem fornecido naturalmente por meio dos alimentos volumosos presentes no seu pasto. -/- Apoio -/- Realização -/- REFERÊNCIAS BIBLIOGRÁFICAS BAH, Mamadou M. et al. 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