Throughout the biological and biomedical sciences there is a growing need for, prescriptive ‘minimum information’ (MI) checklists specifying the key information to include when reporting experimental results are beginning to find favor with experimentalists, analysts, publishers and funders alike. Such checklists aim to ensure that methods, data, analyses and results are described to a level sufficient to support the unambiguous interpretation, sophisticated search, reanalysis and experimental corroboration and reuse of data sets, facilitating the extraction of maximum value from data sets (...) them. However, such ‘minimum information’ MI checklists are usually developed independently by groups working within representatives of particular biologically- or technologically-delineated domains. Consequently, an overview of the full range of checklists can be difficult to establish without intensive searching, and even tracking thetheir individual evolution of single checklists may be a non-trivial exercise. Checklists are also inevitably partially redundant when measured one against another, and where they overlap is far from straightforward. Furthermore, conflicts in scope and arbitrary decisions on wording and sub-structuring make integration difficult. This presents inhibit their use in combination. Overall, these issues present significant difficulties for the users of checklists, especially those in areas such as systems biology, who routinely combine information from multiple biological domains and technology platforms. To address all of the above, we present MIBBI (Minimum Information for Biological and Biomedical Investigations); a web-based communal resource for such checklists, designed to act as a ‘one-stop shop’ for those exploring the range of extant checklist projects, and to foster collaborative, integrative development and ultimately promote gradual integration of checklists. (shrink)

TRANSPORTE DE GAMETAS, FERTILIZAÇÃO E SEGMENTAÇÃO -/- • _____OBJETIVO -/- O entendimento do desenvolvimento embrionário nos estágios iniciais, desde a deposição dos espermatozoides na fêmea, passando pela fertilização deste no ovócito e na formação do zigoto, é de suma importância para diferenciar especialistas em reprodução e manejo reprodutivo no mercado de trabalho e, também, durante a vida acadêmica. Compreender os processos que levam à formação do zigoto na fêmea é essencial para avaliar a capacidade reprodutiva dos animais e, mediante técnicas, (...) avaliar o trato reprodutivo da fêmea e o desenvolvimento do embrião até a formação do feto e, por fim, em um novo animal sadio na propriedade. Com esse trabalho, o estudante de veterinária ou zootecnia, que deseja se aprofundar na fisiologia da reprodução animal, identificará os mecanismos que são envolvidos no transporte dos gametas, bem como os processos que estes últimos devem completar para alcançar a fertilização e para desencadear as divisões iniciais do embrião. -/- • _____INTRODUÇÃO -/- A fertilização ou fecundação é o processo pelo qual os gametas masculino (espermatozoide) e feminino (ovócito) se fundem para gerar um novo indivíduo. Seu êxito depende da culminação adequada dos diferentes processos que devem sofrer os gametas durante sua maduração e percurso; do transporte oportuno destes no trato reprodutivo da fêmea, assim como de uma série de adaptações dos órgãos genitais internos da mãe. A segmentação refere-se às primeiras divisões celulares do embrião. -/- • _____TRANSPORTE DO OVÓCITO -/- O ovócito que é liberado na ovulação, e que se encontra coberto pelas células do cumulus (figura 1), é capturado pela fímbria do infundíbulo ao aderir aos cílios. Esse processo é altamente eficaz, inclusive em espécies onde os ovários possuem várias formações globosas, por exemplo nas porcas, onde os ovidutos capturam entre 95 e 100% dos ovócitos que são ovulados. As contrações das camadas musculares do oviduto e o movimento intenso dos cílios da mucosa faz com que as secreções fluam em direção ao útero, transportando assim o complexo cumulus-ovócito. Esse transporte é relativamente rápido até alcançar a junção da ampola com o istmo (que é considerado o local de fertilização do espermatozoide e ovócito) a partir do qual se torna lento. Devido a fêmea estar em estro, o processo está sob controle endócrino, isto é, controle hormonal através do estradiol. Nas fêmeas domésticas, ao contrário das mulheres, o transporte ao longo do oviduto é extremamente eficiente, pois os embriões passam para o útero sem dificuldade, de modo que gestações ectópicas (tubárias ou em cavidade) são quase inexistentes. A égua, frequentemente, retém por muito tempo os ovócitos não fertilizados no oviduto, provavelmente devido a não secreção de substâncias (como a prostaglandina E) que poderiam favorecer sua passagem, como se propõe que aconteça com os embriões. A figura 2 apresenta um ovócito com suas respectivas estruturas. Figura 1: ovócitos de uma vaca madurados in vitro. Nota-se as células do cumulus que os recobre. -/- Figura 2: estruturas do ovócito de uma ovelha que se encontra na etapa de ovócito secundário, depois da ovulação. Elaborado pelo autor. • _____TRANSPORTE ESPERMÁTICO -/- Para que os espermatozoides sejam capazes de fertilizar o ovócito, deverão sofrer uma série de mudanças bioquímicas e morfológicas ao longo de sua passagem pelo aparelho reprodutor tanto masculino como feminino. Uma vez produzidos na parede do túbulo seminífero, os espermatozoides são liberados em direção ao lúmen tubular e transportados passivamente para uma estrutura ramificada conhecida como rede testicular (rete testis). Dessa rede são conduzidos em direção ao epidídimo passando através de 10 a 20 ductos eferentes localizados no polo superior do testículo. O epidídimo é dividido em três seções denominadas cabeça, corpo e cauda; é constituído por um só ducto longo e tortuoso que continua com o canal deferente. Ao final desemboca nas ampolas seminais, no ducto ejaculatório e na uretra. As funções do epidídimo são as de maduração, transporte e armazenamento dos espermatozoides. O transporte através do epidídimo é lento, aproximadamente de 10 dias em touros, e segue sendo passivo. Os espermatozoides tomados da cabeça do epidídimo são ainda imaturos e incapazes de fertilizar, enquanto os armazenados na cauda são completamente maduros. Durante o trânsito pelo epidídimo os espermatozoides adquirem motilidade e o potencial para fertilizar, o acrossomo é remodelado e a gota citoplasmática migra para o flagelo e é liberada. Quando um macho ejacula com muita frequência, é possível observar espermatozoides com gota citoplasmática no sêmen, já que não há tempo suficiente para que completem sua maduração. Os espermatozoides são expulsados fora do organismo durante a cópula, na masturbação ou em emissões espontâneas. Na ejaculação, os espermatozoides que se encontram suspensos nos fluidos do testículo e do epidídimo, misturam-se ao chegar na uretra com as secreções das glândulas acessórias para formar o sêmen. Essas secreções denominadas plasma seminal, proporcionam substâncias para manter o metabolismo energético das células espermáticas, e integram suas membranas elementos que impedem uma capacitação prematura. Durante a cópula, o sêmen é depositado na vagina ou no útero, variando entre as espécies (tabela 1). Na monta natural, geralmente, o serviço ocorre no momento propício, já que está definido pela fase do ciclo estral em que a fêmea é receptiva ao macho. No entanto, na inseminação artificial, é o macho que deverá determinar o momento ideal, e para isso é importante considerar a vida média dos gametas, ao qual é muito curta no caso dos ovócitos (tabela 1). -/- Tabela 1: local de depósito do sêmen, volume da ejaculação e vida média dos gametas. Espécie Local de deposição Volume (ml) Velocidade de ejaculação Vida média do ovócito Vida média do espermatozoide Bovinos Intravaginal 2 1 – 3 seg 8 h 30 – 48 h Caninos Intravaginal 2 – 30 (10 média) 6 – 45 min 48 – 72 h 9 – 11 d Equinos Intrauterina 50 – 200 20 – 60 seg 6 – 8 h 72 – 120 h Humanos Intravaginal 3 - - 5 – 6 d Ovinos Intravaginal 1 1 – 2 seg 16 – 24 h 30 – 48 h Suínos Intrauterina 200 – 400 5 – 20 min 8 – 10 h 24 – 48 h Onde d = dias; h = horas. A vida fértil do ovócito é muito curta, portanto, o momento do serviço é de grande importância para obter altos índices de fertilização. -/- Independentemente do local em que os espermatozoides sejam depositados no aparelho reprodutor feminino, serão expostos às secreções genitais e sofrem uma série de mudanças em seu trajeto até o local de fertilização antes de penetrar no ovócito. Nas espécies em que o sêmen é depositado na parte cranial da vagina, uma parte do mesmo penetra através da cérvix, enquanto outra parte é eliminada do aparelho genital da fêmea, em pouco tempo, através do fluxo retrógrado. O meio vaginal não é adequado e imobiliza os espermatozoides em pouco tempo, pelo qual deverão entrar no útero onde o ambiente é mais propício. O transporte espermático na fêmea é o resultado da alta contratilidade, do movimento ciliar e o fluido do aparelho genital durante o estro, ao qual está sob controle endócrino e do sistema nervoso. Esse transporte é favorecido pelas características especiais do muco estral, cujas moléculas formam uma espécie de canais que facilitam a passagem dos espermatozoides. Pelo contrário, durante a fase lútea seu transporte é dificultado. Além do meio vaginal, a cérvix também atua como barreira natural para limitar a passagem dos espermatozoides, diminuindo assim a possibilidade de polispermia. Funciona, também, como um filtro que seleciona os espermatozoides aptos dos que não o são, uma vez que somente os primeiros possuem uma motilidade vigorosa que lhes permite passar pelo muco altamente hidratado. Na vaca a cérvix é considerada como um reservatório espermático. Quando atravessam a cérvix, os espermatozoides seguem sua deslocação tanto por movimento próprio como pelas contrações uterinas e tubárias. Nas espécies em que o local de depósito do sêmen do macho na fêmea é intrauterino, como equinos, a principal barreira que os espermatozoides enfrentam é a união ou junção útero-tubárica. A união entre o útero e o oviduto (istmo do oviduto) serve como reservatório funcional dos espermatozoides nas espécies domésticas. Poucos minutos depois da cópula, é possível encontrar alguns espermatozoides no oviduto, que é conhecido como fase de transporte rápido. No entanto, esses espermato-zoides não são os que participam do processo de fertilização e podem apresentar certas anormalidades. Existe um segundo tipo de transporte denominado fase sustentada, a qual consiste na migração prolongada dos espermatozoides em direção as partes mais craniais do aparelho genital feminino, que conduzem à colonização do reservatório funcional e na liberação gradual dos espermatozoides dos reservatórios espermáticos, incluindo este último. O reservatório do istmo fornece aos espermatozoides um ambiente propício, protegendo-os contra a fagocitose, prolongando assim a sua viabilidade. Aqui os esper-matozoides permanecem aderidos a superfície das células ciliadas do epitélio até a finalização de sua capacitação, depois da qual são liberados quando alteram seu padrão de motilidade flagelada, fenômeno conhecido como hipermotilidade, e migram em ondas em direção ao local da fertilização. Dos milhões de espermatozoides ejaculados, somente alguns milhares alcançarão o istmo do oviduto e um número sumamente pequeno será encontrado nas imediações do ovócito no momento da fertilização. -/- • _____CAPACITAÇÃO ESPERMÁTICA E REAÇÃO ACROSSÔMICA -/- A capacitação é um processo gradual e essencial para a fertilização. Os espermato-zoides devem passar por um dado tempo de “incubação” no aparelho genital da fêmea e sofrer uma série de mudanças antes de serem capazes de fecundar o ovócito. A capacita-ção dos espermatozoides começa quando eles entram em contato com as secreções do aparelho genital da fêmea e termina no istmo do oviduto. Durante esse percurso a superfície da cabeça do espermatozoide se modifica já que algumas moléculas como o colesterol são removidas da membrana plasmática, aumentando sua fluidez e alterando suas propriedades bioquímicas. Entre outras coisas, essa reorganização dos lipídios facilita a entrada de cálcio extracelular pelos canais iônicos e ocasiona a desestabilização da membrana, tornando-a mais fusogênica. Também são eliminados outros fatores (conhecidos genericamente como fatores descapacitantes) que expõem receptores membranais indispensáveis para a realização da união entre o espermatozoide e o ovócito durante a fertilização. Os espermatozoides capacitados apresentam um padrão de hipermotilidade e uma maior atividade metabólica, características que devem obter para que sejam capazes de penetrar as camadas do ovócito. A capacitação é necessária para que ocorra a reação acrossômica. A reação acrossomal ou acrossômica (RA) é um fenômeno de exocitose que é desencadeada pela ligação entre as proteínas e receptores localizados na membrana do espermatozoide e a zona pelúcida do ovócito (figura 3). Envolve a fusão da membrana plasmática do espermatozoide com a membrana externa de seu acrossomo; formando, assim, pequenas vesículas, cujo conteúdo de enzimas hidrolíticas, como a hialuronidase e a acrosina, é liberado em direção ao seu exterior, facilitando a penetração da zona pelúcida. A adesão do espermatozoide à zona pelúcida é específica da espécie e depende de glicoproteínas presentes na membrana dos ovócitos maduros; a cabeça do espermatozoide se une com essas glicoproteínas mediante receptores específicos e atravessam em direção oblíqua a zona pelúcida até chegar ao espaço perivitelino. Nos mamíferos, particularmente em roedores e nos humanos, algumas dessas glicoproteínas são conhecidas como ZP1, ZP2 e ZP3. Pensa-se que a união da membrana espermática a esta última é o que desencadeia a reação acrossomal. Posteriormente, as vilosidades do ovócito entram em contato com o espermatozoide e a membrana presente na secreção equatorial da cabeça do espermatozoide, que tem proteínas fusogênicas específicas, une-se a membrana plasmática do ovócito, fusionando-se e permitindo a entrada do núcleo espermático ao citoplasma (figura 4). A capacitação dos espermatozoides é fundamental para o êxito da fertilização, uma vez que apenas os aptos estarão perfeitos e íntegros para que a união e percepção das glicoproteínas presentes nos mesmos possam ocorrer de forma ideal para a penetração deste no ovócito, fertilizá-lo e formar um zigoto. Figura 3: estrutura do espermatozoide. Nota: a membrana é acrossomal e não acrossonal. Elaborado pelo autor. -/- Figura 4: eventos que ocorrem durante a fertilização. A – depois de passar através das células do cumulus, o espermatozoide entra em contato com a zona pelúcida, onde receptores da membrana plasmática reconhecem as proteínas da zona pelúcida; B – é desencadeada, então, a reação acrossomal; C – para que o espermatozoide penetre na zona pelúcida; D – ao atravessar a zona pelúcida e entrar no espaço perivitelino, a cabeça do espermatozoide entra em contato com a membrana vitelina; ambas membranas se fusionam graças ao reconhecimento de proteínas fusogênicas que estão no segmento equatorial. E – ocorre, então, que o núcleo do espermatozoide penetra no citoplasma do ovócito; uma das consequências da fusão da membrana com a cabeça do espermatozoide é a reação cortical, em que os grânulos corticais do ovócito liberam seu conteúdo em direção ao espaço perivitelino, o que resulta na alteração da estrutura da zona pelúcida e da membrana vitelina para bloquear a polispermia. Elaborado pelo autor. • _____CONSEQUÊNCIAS DA PENETRAÇÃO -/- Bloqueio da polispermia -/- A fusão das membranas dos gametas durante a penetração permite a entrada da fosfolipase C zeta (PLCζ) – fator solúvel que provém do espermatozoide – que desencadeia liberação e oscilações de Ca2+ no retículo endoplasmático. Isso, por sua vez, provoca a migração e fusão dos grânulos corticais, com a consequente liberação de enzimas, que mudam tanto a estrutura da zona pelúcida (por exemplo a inativação de ZP3), como a da membrana vitelina. Desse modo, impede-se que outros espermatozoides as penetrem, evitando assim a polispermia (figura 5). -/- Figura 5: os grânulos corticais que encontram-se na periferia do citoplasma, debaixo da superfície da membrana do ovócito, migram e fusionam-se sobre a mesma, liberando seu conteúdo no espaço perivitelino imediatamente depois da penetração do espermatozoide. A – como conse-quência, tanto a membrana vitelina como a zona pelúcida são modificadas, impedindo a entrada de mais espermatozoides, o que evita a polispermia. B – o ovócito retoma, então, sua segunda divisão meiótica, que ocasiona a expulsão do segundo corpúsculo polar, e na formação dos pronúcleos feminino e masculino. C – continuando, os pronúcleos migram, suas membranas se dissolvem e os cromossomos de ambos se condensam e se unem. Completa-se, assim, a singamia e forma-se, então, o zigoto. Elaborado pelo autor baseado nos livros de embriologia e fisiologia da reprodução conforme vida bibliografia. -/- Ativação do ovócito e formação de pronúcleos -/- Na maioria das fêmeas domésticas, com exceção da cadela, o ovócito encontra-se suspenso na metáfase II da segunda meiose no momento da ovulação. A entrada da PLCζ do espermatozoide no citoplasma do ovócito, e a consequente liberação de Ca2+, faz com que o ovócito se ative, terminando a segunda divisão meiótica e expulse o segundo corpo polar. Posteriormente, o material nuclear do ovócito se reorganiza para formar o pronú-cleo feminino. Entretanto, a membrana nuclear do espermatozoide se dissolve, a cromatina descondensa-se, as protaminas são substituídas por histonas, e se forma uma nova membrana nuclear, dando lugar ao pronúcleo masculino. -/- Singamia -/- Uma vez que os pronúcleos feminino e masculino são formados, migram para o centro do ovócito, aproximam-se, suas membranas se dispersam e os cromossomos paternos e maternos se associam, com o qual recupera a condição diploide e dá origem ao zigoto (figura 5). -/- • _____DESENVOLVIMENTO EMBRIONÁRIO -/- Poucas horas após a fertilização ocorre a primeira divisão do zigoto em duas, depois em 4, 8, 16 e 32 células, denominadas blastômeros. Essas divisões mitóticas são conhecidas como divisões de segmentação ou clivagem (figura 6), uma vez que são realizadas sem aumento do citoplasma, de modo que com cada divisão os blastômeros se tornam menores. A partir das 16 células o embrião se chama mórula, e é visto como uma massa celular compacta. A compactação deve-se a informação de proteínas de ligação entre os blastômeros. O embrião acumula líquido em seu interior, formando uma cavidade denominada blastocele. Esse processo é conhecido como blastulação; o embrião, assim, passa a ser chamado de blastocisto. Nessa etapa é possível diferenciar duas populações de células embrionárias: a massa celular interna, embrioblasto ou botão embrionário (que dará origem ao embrião), e a massa celular externa, células superficiais ou trofoblasto, do qual se originam a maioria das membranas fetais. Ao continuar a multiplicação das células e a acumulação de líquido, o blastocisto aumenta de tamanho, convertendo-se em blastocisto expandido. A zona pelúcida torna-se mais fina e, finalmente, o embrião eclode; isto é, o embrião é liberado da zona pelúcida. -/- • _____FERTILIZAÇÕES ATÍPICAS -/- Polispermia -/- É a penetração de dois ou mais espermatozoides no óvulo. Esta condição é letal nos mamíferos, já que o número cromossômico desse zigoto é maior que 2n, o envelheci-mento do ovócito da porca, como consequência do serviço tardio, favorece a apresentação da polispermia, por isso, é comum ver números de nascimentos de média de 10 a 12 leitões por parição nessa espécie. Nas aves, no entanto, a penetração de mais de um espermatozoide é normal, embora apenas um pronúcleo masculino se formará, fundindo-se com o feminino. -/- Figura 6: etapas do processo de segmentação/clivagem. Fonte: aula de reprodução da professora Domenica Palomaris, UFT. -/- Ginogênese -/- É o desenvolvimento de um embrião a partir de um óvulo normal fecundado por um espermatozoide, mas sem a fusão dos cromossomos masculinos com os da fêmea. A função do espermatozoide, nesse caso, é a de ativação do ovócito para que este inicie seu desenvolvimento, mas não há fusão com o núcleo do espermatozoide. Ocorre em plantas, em nematódeos e em algumas espécies de peixes, por exemplo a Poecilia formosa, espécie em que os ovócitos das fêmeas são ativados por machos de outra espécie relacio-nada. -/- Partenogênese -/- Consiste no desenvolvimento do embrião sem a participação do espermatozoide. Ocorre em alguns insetos, o zangão, por exemplo, é partenogenético. Também pode apresentar-se em perus, cujos embriões são machos e, geralmente, morrem antes da eclosão. -/- • _____GÊMEOS -/- Existem dois tipos de gêmeos: idênticos ou monozigóticos e os não idênticos ou dizigóticos. -/- Idênticos ou monozigóticos -/- Originam-se do mesmo zigoto, sendo assim, possuem o mesmo genótipo e um fenótipo similar e, portanto, são do mesmo sexo. Em laboratório é possível gerá-los ao seccionar uma mórula em duas ou mais partes, por meio de um micromanipulador. Uma vez que possuem o mesmo genótipo, os produtos resultantes são clones. -/- Não idênticos ou dizigóticos -/- Provêm da fertilização de dois óvulos distintos por espermatozoides diferentes. Possuem, portanto, genótipos e fenótipos diferentes, e podem ser de sexo diferente. -/- REFERÊNCIAS BIBLIOGRÁFICAS -/- ALBERTS, Bruce et al. Biologia molecular da célula. Artmed Editora, 2010. AUSTIN, Colin Russell; SHORT, Roger Valentine. Reproduction in Mammals, Book I: Germ Cells and Fertilization. 1982. BEARDEN, Henry Joe et al. Reproducción animal aplicada. México: Manual Moderno, 1982. BOSCH, P.; WRIGHT JR, R. W. The oviductal sperm reservoir in domestic mammals. Archivos de medicina veterinaria, v. 37, n. 2, p. 95-105, 2005. CAPALLEJAS, Roberto Brito; RODRÍGUEZ, Lourdes Tagle. Fisiología de la reproducción animal: con elementos de biotecnología. Editorial Félix Varela, 2010. CROXATTO, Horacio B. Physiology of gamete and embryo transport through the fallopian tube. Reproductive biomedicine online, v. 4, n. 2, p. 160-169, 2002. CUPPS, Perry T. (Ed.). Reproduction in domestic animals. Elsevier, 1991. DIEDRICH, Smidt et al. Endocrinología y Fisiología de la Reproducción de los Animales Zootécnicos. 1972. DUKES, Henry Hugh; SWENSON, Melvin J.; REECE, William O. Dukes fisiologia dos animais domésticos. Editora Guanabara Koogan, 1996. FERREIRA, A. de M. Reprodução da fêmea bovina: fisiologia aplicada e problemas mais comuns (causas e tratamentos). Juiz de Fora: Minas Gerais–Brasil, p. 422, 2010. HAFEZ, Elsayed Saad Eldin; HAFEZ, Bahaa. Reprodução animal. São Paulo: Manole, 2004. HUNTER, Ronald Henry Fraser. The Fallopian tubes in domestic mammals: how vital is their physiological activity?. Reproduction Nutrition Development, v. 45, n. 3, p. 281-290, 2005. HUNTER, R. H. F.; RODRIGUEZ‐MARTINEZ, H. Capacitation of mammalian spermatozoa in vivo, with a specific focus on events in the Fallopian tubes. Molecular Reproduction and Development: Incorporating Gamete Research, v. 67, n. 2, p. 243-250, 2004. GALINA, Carlos; VALENCIA, Javier. Reproducción de los animales domésticos. 2006. HOPPER, Richard M. (Ed.). Bovine reproduction. John Wiley & Sons, 2014. HYTTEL, Poul; SINOWATZ, Fred; VEJLSTED, Morten. Embriologia veterinária. Elsevier Brasil, 2012. KÖLLE, Sabine; REESE, Sven; KUMMER, Wolfgang. New aspects of gamete transport, fertilization, and embryonic development in the oviduct gained by means of live cell imaging. Theriogenology, v. 73, n. 6, p. 786-795, 2010. MCKINNON, Angus O. et al. (Ed.). Equine reproduction. John Wiley & Sons, 2011. OLIVERA, Martha et al. El espermatozoide, desde la eyaculación hasta la fertilización. Revista Colombiana de Ciencias Pecuarias, v. 19, n. 4, p. 426-436, 2006. PLANT, Tony M.; ZELEZNIK, Anthony J. (Ed.). Knobil and Neill's physiology of reproduction. New York: Academic Press, 2014. RODRIGUEZ-MARTINEZ, Heriberto. Role of the oviduct in sperm capacitation. Theriogenology, v. 68, p. S138-S146, 2007. SAAVEDRA LEOS, María Dolores. Estudio de la composición de los gránulos corticales y del oolema de ovocitos porcinos y bovinos madurados y fecundados in vitro. Proyecto de investigación:, 2010. SENGER, Phillip L. et al. Pathways to pregnancy and parturition. Current Conceptions, Inc, 2004. SUAREZ, Susan S. The oviductal sperm reservoir in mammals: mechanisms of formation. Biology of Reproduction, v. 58, n. 5, p. 1105-1107, 1998. VALENCIA MÉNDEZ, Javier de J. Fisiología de la reproducción porcina. 1986. -/- FIXAÇÃO DO ASSUNTO -/- 1. Defina e diferencie fertilização e segmentação. -/- 2. Disserte sobre o transporte do ovócito. Por que no istmo o transporte do ovócito se torna lento? -/- 3. Fale sobre a eficiência do transporte do gameta no trato genital da fêmea e sobre a retenção de ovócitos pela égua. -/- 4. Defina as células do cumulus e explique seu papel sobre o ovócito. -/- 5. Quais as estruturas que compõem o ovócito? Qual a função de cada uma? -/- 6. Todos os ovócitos das fêmeas domésticas são iguais? Justifique. -/- 7. Disserte sobre o papel dos hormônios e das secreções sobre o transporte do ovócito no trato genital da fêmea. -/- 8. Disserte sobre o transporte do espermatozoide. Por que há transporte rápido e lento dos espermatozoides? -/- 9. Fale sobre o local de deposição do sêmen nas espécies domésticas e como esse influen-cia na eficiência da reprodução. -/- 10. Por que a vida média do espermatozoide canino é maior que as outras espécies? -/- 11. Quais as mudanças que os espermatozoides precisam sofrer para conseguir êxito na fertilização e por quê? -/- 12. Defina fase de transporte rápido, fase sustentada e hipermotilidade. Qual a importân-cia de cada um? -/- 13. Como ocorre a reação acrossômica? -/- 14. O que é polispermia e como ocorre seu bloqueio? 15. Como ocorre a ativação do ovócito e como se formam os pronúcleos? -/- 16. O que é e qual a importância da singamia? -/- 17. Disserte sobre as divisões de segmentação e qual a importância destas para o êxito da reprodução. -/- 18. Defina e diferencia mórula e blastocisto. -/- 19. Defina e diferencie ginogênese e partenogênese. -/- 20. Qual o papel endócrino e quais hormônios e enzimas atuam sobre o transporte de gametas, sobre a fertilização e sobre a segmentação? (shrink)

Dialogamos con Cintia Rodríguez Garat, quien obtuvo el Primer Premio Bioética 2023 de la Fundación Jaime Roca por su trabajo “Resiliencia y salud pública de las mujeres mapuce ante el cambio climático. Un análisis desde una perspectiva intercultural, participativa y de derechos humanos”.

Holobionts are symbiotic assemblages composed by a host plus its microbiome. The status of holobionts as individuals has recently been a subject of continuous controversy, which has given rise to two main positions: on the one hand, holobiont advocates argue that holobionts are biological individuals; on the other, holobiont detractors argue that they are just mere chimeras or ecological communities, but not individuals. Both parties in the dispute develop their arguments from the framework of the philosophy of biology, in terms (...) of what it takes for a “conglomerate” to be considered an interesting individual from a biological point of view. However, the debates about holobiont individuality have important ontological implications that have remained vaguely explored from a metaphysical framework. The purpose of this paper is to cover that gap by presenting a metaphysical approach to holobionts individuality. Drawing upon a conception of natural selection that puts the focus on the transgenerational recurrence of the traits and that supports the thesis that holobionts are units of selection, we argue that holobionts bear emergent traits and exert downward powers over the entities that compose them. In this vein, we argue, a reasonable argument can be made for conceiving holobionts as emergent biological individuals. (shrink)

Bourrat and Griffiths :33, 2018) have recently argued that most of the evidence presented by holobiont defenders to support the thesis that holobionts are evolutionary individuals is not to the point and is not even adequate to discriminate multispecies evolutionary individuals from other multispecies assemblages that would not be considered evolutionary individuals by most holobiont defenders. They further argue that an adequate criterion to distinguish the two categories is fitness alignment, presenting the notion of fitness boundedness as a criterion that (...) allows divorcing true multispecies evolutionary individuals from other multispecies assemblages and provides an adequate criterion to single out genuine evolutionary multispecies assemblages. A consequence of their criterion is that holobionts, as conventionally defined by hologenome defenders, are not evolutionary individuals except in very rare cases, and for very specific host-symbiont associations. This paper is a critical response to Bourrat and Griffiths’ arguments and a defence of the arguments presented by holobiont defenders. Drawing upon the case of the hologenomic basis of the evolution of sanguivory in vampire bats, I argue that Bourrat and Griffiths overlook some aspects of the biological nature of the microbiome that justifies the thesis that holobionts are evolutionarily different to other multispecies assemblages. I argue that the hologenome theory of evolution should not define the hologenome as a collection of genomes, but as the sum of the host genome plus some traits of the microbiome which together constitute an evolutionary individual, a conception I refer to as the stability of traits conception of the hologenome. Based on that conception I argue that the evidence presented by holobiont defenders is to the point, and supports the thesis that holobionts are evolutionary individuals. In this sense, the paper offers an account of the holobiont that aims to foster a dialogue between hologenome advocates and hologenome critics. (shrink)

Contemporary biological research has suggested that some host–microbiome multispecies systems (referred to as “holobionts”) can in certain circumstances evolve as unique biological individual, thus being a unit of selection in evolution. If this is so, then it is arguably the case that some biological adaptations have evolved at the level of the multispecies system, what we call hologenomic adaptations. However, no research has yet been devoted to investigating their nature, or how these adaptations can be distinguished from adaptations at the (...) species-level (genomic adaptations). In this paper, we cover this gap by investigating the nature of hologenomic adaptations. By drawing on the case of the evolution of sanguivory diet in vampire bats, we argue that a trait constitutes a hologenomic adaptation when its evolution can only be explained if the holobiont is considered the biological individual that manifests this adaptation, while the bacterial taxa that bear the trait are only opportunistic beneficiaries of it. We then use the philosophical notions of emergence and inter-identity to explain the nature of this form of individuality and argue why it is special of holobionts. Overall, our paper illustrates how the use of philosophical concepts can illuminate scientific discussions, in the trend of what has recently been called metaphysics of biology. (shrink)

Symbiosis plays a fundamental role in contemporary biology, as well as in recent thinking in philosophy of biology. The discovery of the importance and universality of symbiotic associations has brought new light to old debates in the field, including issues about the concept of biological individuality. An important aspect of these debates has been the formulation of the hologenome concept of evolution, the notion that holobionts are units of natural selection in evolution. This review examines the philosophical assumptions that underlie (...) recent proposal of the hologenome concept of evolution, and traces those debates back in time to their historical origins, to the moment when the connection between the topics of symbiosis and biological individuality first caught the attention of biologists. The review is divided in two parts. The first part explores the historical origins of the connection between the notion of symbiosis and the concept of biological individuality, and emphasizes the role of A. de Bary, R. Pound, A. Schneider and C. Merezhkowsky in framing the debate. The second part examines the hologenome concept of evolution and explores four parallelisms between contemporary debates and the debates presented in the first part of the essay, arguing that the different debates raised by the hologenome concept were already present in the literature. I suggest that the novelty of the hologenome concept of evolution lies in the wider appreciation of the importance of symbiosis for maintaining life on Earth as we know it. Finally, I conclude by suggesting the importance of exploring the connections among contemporary biology, philosophy of biology and history of biology in order to gain a better understanding of contemporary biology. (shrink)

This paper aims to offer a new argument in defence bacterial species pluralism. To do so, I shall first present the particular issues derived from the conflict between the non-theoretical understanding of species as units of classification and the theoretical comprehension of them as units of evolution. Secondly, I shall justify the necessity of the concept of species for the bacterial world, and show how medicine and endosymbiotic evolutionary theory make use of different concepts of bacterial species due to their (...) distinctive purposes. Finally, I shall show how my argument provides a new source of defence for bacterial pluralism. (shrink)

This bulletin contains a summary of the main topics of discussion in truthmaker theory, namely: the definition of truthmakers, problems with Truthmaker Necessitarianism and Truthmaker Maximalism, the ontological burden of truthmakers and the recalcitrant topic of truthmakers for negative truths.

Political philosophy in the last decades has turned away from universal narratives of progress, on grounds that these narratives produce exclusion and justify domination. However, the universal values that underlie emancipatory political projects seem to presuppose universal history, which explains its persistence in some contemporary political philosophers committed to such projects. In order to find a response to the paradox according to which universal history is inherently exclusionary and yet necessary to uphold universal values, I examine the contrast between Adorno’s (...) and Lyotard’s perspectives on the problem of writing history ‘after Auschwitz’. For both philosophers, Auschwitz interrupts our fundamental normative and cognitive values, because any attempt to identify the meaning of the camps by means of these values misunderstands the suffering that took place in them. Yet this interruption produces a feeling that calls for the institution of new universal normative values. For Adorno, this value is a purely negative command to act in such a way that Auschwitz does not repeat itself. For Lyotard, by contrast, it is the demand to invent new idioms that make it possible to find meaning in Auschwitz. (shrink)

Philippe Huneman has recently questioned the widespread application of mechanistic models of scientific explanation based on the existence of structural explanations, i.e. explanations that account for the phenomenon to be explained in virtue of the mathematical properties of the system where the phenomenon obtains, rather than in terms of the mechanisms that causally produce the phenomenon. Structural explanations are very diverse, including cases like explanations in terms of bowtie structures, in terms of the topological properties of the system, or in (...) terms of equilibrium. The role of mathematics in bowtie structured systems and in topologically constrained systems has recently been examined in different papers. However, the specific role that mathematical properties play in equilibrium explanations requires further examination, as different authors defend different interpretations, some of them closer to the new-mechanistic approach than to the structural model advocated by Huneman. In this paper, we cover this gap by investigating the explanatory role that mathematics play in Blaser and Kirschner’s nested equilibrium model of the stability of persistent long-term human-microbe associations. We argue that their model is explanatory because: i) it provides a mathematical structure in the form of a set of differential equations that together satisfy an ESS; ii) that the nested nature of the ESSs makes the explanation of host-microbe persistent associations robust to any perturbation; iii) that this is so because the properties of the ESS directly mirror the properties of the biological system in a non-causal way. The combination of these three theses make equilibrium explanations look more similar to structural explanations than to causal-mechanistic explanation. (shrink)

1. The Bundle Theory I shall discuss is a theory about the nature of substances or concrete particulars, like apples, chairs, atoms, stars and people. The point of the Bundle Theory is to avoid undesirable entities like substrata that allegedly constitute particulars. The version of the Bundle Theory I shall discuss takes particulars to be entirely constituted by the universals they instantiate.' Thus particulars are said to be just bundles of universals. Together with the claim that it is necessary that (...) particulars have constituents, the fundamental claim of the Bundle Theory is: (BT) Necessarily, for every particular x and every entity y, y constitutes x if and only ify is a universal and x instantiates y. 2 The standard and supposedly devastating objection to the Bundle Theory is that it entails or is committed to a false version of the Principle of Identity of Indiscernibles (Armstrong 1978: 91, Loux 1998: 107), namely: (Pll) Necessarily, for all particulars x and y and every universal z, if z is instantiated by x if and only if z is instantiated byy, then x is numerically identical with y. The most famous counterexample to the Identity of Indiscernibles is that put forward by Max Black, consisting of a world where there are only two iron spheres two miles apart from each other, having the same diameter, temperature, colour, shape, size, etc (Black 1952: 156). Let us from now on think of the properties of the spheres in this world as universals. The possibility of this world, which I shall hereafter refer to as 'Black's world', makes (Pll) false.' And according to common philosophical opinion this means that the Bundle Theory is false.. (shrink)

Peter Milne has tried to refure Truthmaker Maximalism. the thesis that every truth has a truthmaker, by producing a simple and direct counterexample to it, the sentence M: This sentence has no truthmaker. I argue that, contrary to what Milne argues, on Truthmaker Maximalism M is equivalent to the Liar, which gives the truthmaker maximalist a way to defend his position from Milne's counterexample: to argue that M expresses no proposition.

The hologenome concept of evolution is a hypothesis about the evolution of animals and plants. It asserts that the evolution of animals and plants was partially triggered by their interactions with their symbiotic microbiomes. In that vein, the hologenome concept posits that the holobiont (animal host + symbionts of the microbiome) is a unit of selection. -/- The hologenome concept has been severely criticized on the basis that selection on holobionts would only be possible if there were a tight transgenerational (...) host-genotype-to-symbiont-genotype connection. As our current evidence suggests that this is not the case for most of the symbiont species that compose the microbiome of animals and plants, the opportunity for holobiont selection is very low in relation to the opportunity for selection on each of the species that compose the host microbiome. Therefore, holobiont selection will always be disrupted ‘from below’, by selection on each of the species that compose the microbiome. -/- This thesis constitutes a conceptual effort to defend philosophically the hologenome concept. I argue that the criticism according to which holobiont selection requires tight transgenerational host-genotype-to-symbiont-genotype connection is grounded on a metaphysical view of the world according to which the biological hierarchy needs to be nested, such that each new level of selection includes every entity from below. Applied to hologenomes, it entails that the hologenome is a collection of genomes, and selection of hologenomes is assumed to entail cospeciation of the host with the species that constitute its microbiome. -/- Against that interpretation, I propose the ‘stability of traits’ account, according to which hologenome evolution is the result of the action of natural selection in a non-nested hierarchical world. In that vein, hologenome evolution does not entail cospeciation, and thus it does not require tight transgenerational host-genotype-to-symbiont-genotype connection. By embracing a multilevel selection perspective, I argue that hologenome evolution results from the simultaneous action of natural selection on each of the lineages that compose the microbiome, and on the assemblage composed by the host genome plus the functional traits of its microbiome. Hologenome selection occurs when the evolution of the traits of the microbiome result from their effects on the fitness of the host, and it can take the form of multilevel selection 1, or multilevel selection 2. In both cases, hologenome selection entails the evolution of microbiome traits, as well as evolution of the host genome, rather than cospeciation of lineages. (shrink)

According to one of Leibniz's theories of contingency a proposition is contingent if and only if it cannot be proved in a finite number of steps. It has been argued that this faces the Problem of Lucky Proof , namely that we could begin by analysing the concept ‘Peter’ by saying that ‘Peter is a denier of Christ and …’, thereby having proved the proposition ‘Peter denies Christ’ in a finite number of steps. It also faces a more general but (...) related problem that we dub the Problem of Guaranteed Proof . We argue that Leibniz has an answer to these problems since for him one has not proved that ‘Peter denies Christ’ unless one has also proved that ‘Peter’ is a consistent concept, an impossible task since it requires the full decomposition of the infinite concept ‘Peter’. We defend this view from objections found in the literature and maintain that for Leibniz all truths about created individual beings are contingent. (shrink)

States restrict immigration on a massive scale. Governments fortify their borders with walls and fences, authorize border patrols, imprison migrants in detention centers, and deport large numbers of foreigners. Unjust Borders: Individuals and the Ethics of Immigration argues that immigration restrictions are systematically unjust and examines how individual actors should respond to this injustice. Javier Hidalgo maintains that individuals can rightfully resist immigration restrictions and often have strong moral reasons to subvert these laws. This book makes the case that (...) unauthorized migrants can permissibly evade, deceive, and use defensive force against immigration agents, that smugglers can aid migrants in crossing borders, and that citizens should disobey laws that compel them to harm immigrants. Unjust Borders is a meditation on how individuals should act in the midst of pervasive injustice. (shrink)

Derek Parfit influentially defends reductionism about persons, the view that a person’s existence just consists in the existence of a brain and body and the occurrence of a series of physical and mental events. Yet some critics, particularly Mark Johnston, have raised powerful objections to Parfit’s reductionism. In this paper, I defend reductionism against Johnston. In particular, I defend a radical form of reductionism that Buddhist philosophers developed. Buddhist reductionism can justify key features of Parfit’s position, such as the claims (...) that personal identity is not what matters and can also be indeterminate. Furthermore, Buddhist reductionism can avoid Johnston’s objections to Parfit’s reductionism. I conclude that reductionists have good reasons to favor Buddhist reductionism over Parfit’s version. (shrink)

The German word Destruktion was used by Heidegger in the sense that philosophy should destroy some ontological concepts and the everyday meanings of certain words. Tradition allows the transmission of knowledge and sensations of continuity and connection with the past, but it must be critically evaluated so that it does not perpetuate certain prejudices. According to Heidegger, tradition transmits, but it also conceals. Tradition induces self-evidence and prevents us from accessing the origin of concepts. It makes us believe that we (...) do not need to return to that origin. Making tradition transparent dissolves the concealments it has provoked. Here I will apply this idea to the mental and the physical by suggesting that the mind-body problem has inherited occultations that are born in Descartes himself. As a result, what could be a new philosophical framework for the research in consciousness emerges: That as an individual cognitive being I cannot avoid splitting reality into what I am and what I am not, extending then the individual duality to a collective error transmitted culturally. (shrink)

El artículo analiza el papel del resentimiento en la Teoría de los sentimientos morales de Adam Smith y su conexión con el proceso de la simpatía mutua por medio del cual el “espectador imparcial” asume plenamente el resentimiento de la víctima, al considerar que su pasión se rige por los principios de la propiedad y la justicia. Se sostiene que el resentimiento no solo cumple un rol central en la teoría del castigo de Adam Smith, en la medida en que (...) permite retribuir, disuadir y rehabilitar al victimario sino que, además, aporta a la discusión contemporánea sobre el perdón y la reconciliación, pues convoca la posibilidad de superar el resentimiento y restablecer las relaciones sociales entre el agresor y la víctima. (shrink)

Bertrand Russell argued that any attempt to get rid of universals in favor of resemblances fails. He argued that no resemblance theory could avoid postulating a universal of resemblance without falling prey to a vicious infinite regress. He added that admitting such a universal of resemblance made it pointless to avoid other universals. In this paper I defend resemblance nominalism from both of Russell's points by arguing that (a) resemblance nominalism can avoid the postulation of a universal of resemblance without (...) falling into a vicious infinite regress, and (b) even if resemblance nominalism had to admit a universal of resemblance, this would not make it pointless to avoid postulating other universals. (shrink)

A large body of evidence suggests that the Personalized System of Instruction (PSI) improves learning. In courses that use PSI, the material is divided into units, students must pass a test on each unit before advancing to the next unit, there’s no group-level instruction, and students advance in the course at their own pace. While studies find that PSI improves learning outcomes in a wide range of settings, researchers haven’t studied the effectiveness of PSI in critical thinking classes. In this (...) paper, I argue that teaching critical thinking with PSI can effectively promote critical thinking skills. I describe a course that uses PSI to teach critical thinking and I present evidence from pre- and post-tests that indicates that students substantially improved their reasoning skills in this course. I also discuss the costs and drawbacks of using this method of instruction and consider ways of addressing these problems. (shrink)

Several noted economists and prominent international organizations have recently advocated for the implementation of guest worker programs in developed states. Their primary argument is that guest worker programs would serve as a powerful mechanism for reducing global poverty and inequality. For example, economist Dani Rodrik estimates that guest worker programs in wealthy states would generate $200 billion or more annually for poor countries. According to Rodrik, liberalizing the temporary movement of workers would “produce the largest possible gains for the world (...) economy and for poor countries in particular,” in comparison with other policies, such as trade liberalization. (shrink)

In der Kritik der Urteilskraft vertritt Kant noch die analogische Beziehung zwischen Schönheit und Sittlichkeit (KU, AA 05: 351–354). Aber wir befinden uns hier in einem ganz anderen Zusammenhang. Und dies nicht nur, weil die Erörterung dieser analogischen Beziehung eine Lösung für das Problem der Verknüpfung zwischen theoretischer und praktischer Vernunft beansprucht. Die Reflexionen in den Vorlesungen über Anthropologie über die pragmatische Dimension des Geschmacks setzten die Möglichkeit dieser Verknüpfung bereits voraus, bevor Kant eine kritische Begründung derselben erreichte. Wir dürfen (...) aber diese Reflexionen nicht als das Ergebnis unreifer Versuche zur Lösung dieses kritischen Problems der Rationalitätstheorie Kants deuten. Während der Paragraph 59 der Kritik der Urteilskraft Teil der spekulativen Philosophie ist, wird die Kritik des Geschmacks in den Vorlesungen über Anthropologie vielmehr insofern sinnvoll, da sie zu einem pragmatischen, populären und aufgeklärten Bildungsprogramm der Anthropologie Kants gehört. (shrink)

El objetivo de este artículo es realizar una historización del sistema sanitario de Neuquén, concretamente atendiendo a los programas de salud aplicados en esta provincia desde su surgimiento hasta el año 2020. En este marco, en primer lugar, me enfocaré en los lineamientos políticos que definieron las bases ideológicas de las políticas públicas llevadas a cabo en la atención sanitaria neuquina, y, en segundo lugar, examinaré las variables estadísticas publicadas por el sistema de salud provincial referidas a las condiciones materiales (...) de atención médica de la población en general, y de las mujeres indígenas mapuce en particular. Para efectuar dicho abordaje, analizaré específicamente la localidad de Las Coloradas. -/- . (shrink)

Aunque no es posible ofrecer aquí un análisis detallado de las diferentes cues tionesimplicadas en la teoría de las representaciones en la Modernidad, sí pode mos atender auno de sus aspectos más relevantes, presente en la exposición de Leibniz, Wolff,Baumgarten y Kant, a saber: el reconocimiento progresivo y la vin dicación de unconocimiento específicamente sensible como un tipo específico de conocimiento en lafilosofía escolar alemana del siglo XVIII. A pesar de que Leibniz atribuye al conocimiento claro y confuso el grado (...) más bajo en su esquema de los niveles del conocimiento, tambiénes cierto que su exposición apunta ya a la irre ductibilidad de este ámbito en unconocimiento finito como el humano. Por lo demás, lo confuso aquí adquiere sentido en elsistema del saber en la medida en que Leibniz considera que todos los conocimientos obre cuestiones de hecho, si bien falibles, se encuentran en conexión con la verdad en lamedida en que parti cipan de la misma, al expresar el fundamento último de lo real y sersusceptibles de perfectibilidad en el seno de una subjetividad dinámica que comienza aser entendida como unidad vital. En Wolff y Baumgarten se profundiza en la vía que esabierta ya por Leibniz: la exposición de los niveles de conocimiento en el marco de unaimbricación de la lógica de la representación con una psicología vitalista, en la que sereconocerá la experiencia del sentimiento como expresión subjetiva de la perfectibilidaddel conocimiento humano. Aunque la filosofía de Kant supondrá una ruptura con laexposición escolar de esta teoría de los niveles de conocimiento o los tipos derepresentación, lo cierto es que el nacimiento de su teoría de la sensi bilidad tiene lugar enel marco histórico de esta concepción tradicional. (shrink)

The units or levels of selection debate concerns the question of what kind of biological systems are stable enough that part of their evolution is a result of the process of natural selection acting at their level. Traditionally, the debate has concerned at least two different, though related, questions: the question of the level at which interaction with the environment occurs, and the question of the level at which reproduction occurs. In recent years, biologists and philosophers have discussed a new (...) aspect of this debate, namely the possibility that certain multi-species consortia formed by a host and its microbiome may act as a unit of selection. This thesis, however, has not been without criticism, as it is doubtful that such consortia could meet the conditions required to achieve the degree of stability that would allow them to experience natural selection. The purpose of this paper is to systematically examine such criticisms and to defend the thesis that the holobiont/hologenome can act as a genuine level of selection both in the form of an interactor and in the form of a reproducer. To do so, it will be argued that the microbiome should be characterized in functional rather than taxonomic terms. (shrink)

Many political theorists argue that immigration restrictions are unjust and defend broadly open borders. In this paper, I examine the implications of this view for individual conduct. In particular, I argue that the citizens of states that enforce unjust immigration restrictions have duties to disobey certain immigration laws. States conscript their citizens to help enforce immigration law by imposing legal duties on these citizens to monitor, report, and refrain from interacting with unauthorized migrants. If an ideal of open borders is (...) true, these laws are unjust. Furthermore, if citizens comply with their legal duties, they contribute to violating the rights of migrants. We are obligated to refrain from contributing to rights-violations. So, citizens are obligated to disobey immigration laws. I defend the moral requirement to disobey immigration laws against the objection that disobedience to the law is excessively risky and the objection that citizens have political obligations to obey the law. (shrink)

Margulis’ evolutionary theory entails a revision of certain core concepts of traditional biology. One of these changes is related to the hot debate about units of selection. This paper considers Margulis’ proposal as a new research tradition (RT) and evaluates its consequences to the mentioned issue. Three ideas are suggested here: firstly, that her theory represents the revision of many classical biological concepts; secondly, that her position implies a reappraisal of many traditional issues in philosophy of biology; and thirdly, that (...) studying it from Lakatos and Laudan’s ideas about RT allows us to enlighten the richness of her theory. (shrink)

In my book *Resemblance Nominalism* I argued that the truthmakers of ´a and b resemble each other´ are just a and b. In his "Resemblance Nominalism and counterparts" Alexander Bird objects to my claim that the truthmakers of ´a and b resemble each other´ are just a and b. In this paper I respond to Bird´s objections.

States heavily restrict immigration, and many people violate these restrictions. For example, unauthorized immigrants cross borders without official permission, and other actors, such as people smugglers, assist them in doing so. How should we evaluate resistance to immigration law from a moral perspective? In this article, I survey recent work on the ethics of resisting immigration law. In particular, I examine three categories of resistance to immigration law as the following: unauthorized immigration, people smuggling, and citizens' resistance to laws that (...) prohibit them from assisting or interacting with unauthorized immigrants. (shrink)

ABSTRACT Do Buddhist philosophical commitments support a particular theory of well-being? Most authors who have examined this question argue that Buddhist ideas are compatible with multiple theories of well-being. In this paper, I contend that one tradition of Buddhist philosophy—Abhidharma—does imply a specific theory of welfare. In particular, Abhidharma supports hedonism. Most Ābhidharmikas claim that only property-particulars called dharmas ultimately exist and I argue that an Abhidharmic theory of well-being should only refer to these properties. Yet the only dharmas that (...) could plausibly be intrinsically good are phenomenal properties that are good in virtue of how they feel. Thus, the only intrinsically good things are pleasures. I defend this surprising conclusion from various interpretative objections and show that my argument can also inform contemporary philosophical debates about welfare. (shrink)

Resemblance Nominalism is the view that denies universals and tropes and claims that what makes F-things F is their resemblances. A famous argument against Resemblance Nominalism is Russell's regress of resemblances, according to which the resemblance nominalist falls into a vicious infinite regress. Aristocratic Resemblance Nominalism, as opposed to Egalitarian Resemblance Nominalism, is the version of Resemblance Nominalism that claims that what makes F-things F is that they resemble the F-paradigms. In this paper I attempt to show that a recently (...) advocated strategy to stop Russell's regress by using paradigms does not succeed. (shrink)

This paper discusses practical akrasia from the perspective of the sophisticated form of moral subjectivism that can be derived from Nuno Venturinha’s (2018) remarks on moral matters.

Several political theorists argue that states have rights to self-determination and these rights justify immigration restrictions. Call this: the self-determination argument for immigration restrictions. In this article, I develop an objection to the self-determination argument. I argue that if it is morally permissible for states to restrict immigration because they have rights to self-determination, then it can also be morally permissible for states to deport and denationalize their own citizens. We can either accept that it is permissible for states to (...) deport and denationalize their own citizens or reject the self-determination argument. To avoid this implication, we should reject the self-determination argument. That is, we should also reject the conclusion that rights to self-determination can justify any significant immigration restrictions. (shrink)

Interpretando a Nietzsche, podríamos afirmar que la embriaguez dionisíaca le posibilita al humano dirigirse afectivamente hacia lo externo, borrando incluso y paradójicamente ese límite que determinaría dónde empieza su ser y dónde aquello a lo que su ser es empujado. Trías recoge esta determinación en un concepto clave de su filosofía al denominarnos “ser del límite”. En ambos filósofos somos radicalmente pasión creadora; somos un animal límite y caótico, sufriente por queriente, y potencialmente feliz por el mismo motivo. Está en (...) nuestras manos investigar, tras el reconocimiento de esta condición estética, sensible e insalvable de lo humano, cómo vivir. (shrink)

Since 1968, the irreversible loss of functioning of the whole brain, called brain death, is assimilated to individual’s death. The almost universal acceptance of this neurological criterion of death had decisive consequences for the contemporary medicine, such as the withdrawal of mechanical ventilation in these patients and organ retrieval for transplantation. The new criterion was successfully accepted in part because the assimilation of brain death state to death was presented by medicine --and acritically assumed by most of societies-- as a (...) scientific and objective fact. Nevertheless, many people do not think that the patients suffering brain death are actually dead. We show here that those people are not necessarily wrong. It can be argued that, in fact, the justification of the neurological criterion is not scientific but moral. We outline the thesis that the problem surrounding the vital status of brain dead patients is due to a confusion between factual and normative questions. Furthermore, we claim that the donation of organs and the withdrawal of life-support could be ethically acceptable even if the patients suffering brain death are considered as alive. As an alternative to the dead donor rule, we propose a justification for organ donation of brain-dead patients based on the (moral) concepts of harm and consent : what truly justifies the procurement of organs on those patients is not that they are dead, but that they wish to donate their organs and that, since they have irreversibly lost their brain, they cannot be harmed. (shrink)

ABSTRACTPeople smugglers help transport migrants across international borders without authorization and in return for compensation. Many people object to people smuggling and believe that the smuggling of migrants is an evil trade. In this paper, I offer a qualified defense of people smuggling. In particular, I argue that people smuggling that assists refugees in escaping threats to their rights can be morally justified. I then rebut the objections that people smugglers exploit migrants, have defective motivations, and wrongly violate the law. (...) My conclusion is that people smuggling is sometimes a permissible way of helping refugees to evade unjust immigration restrictions and compelling states to bear their fair share of the global refugee population. (shrink)

In most domains of human life, we are willing to accept that there are experts with greater knowledge and competencies that distinguish them from non-experts or laypeople. Despite this fact, the very recognition of expertise curiously becomes more controversial in the case of “moral experts”. Do moral experts exist? And, if they indeed do, are there ethical reasons for us to follow their advice? Likewise, can emerging technological developments broaden our very concept of moral expertise? In this article, we begin (...) by arguing that the objections that have tried to deny the existence (and convenience) of moral expertise are unsatisfactory. After that, we show that people have ethical reasons to ask for a piece of moral advice in daily life situations. Then, we argue that some Artificial Intelligence (AI) systems can play an increasing role in human morality by becoming moral experts. Some AI-based moral assistants can qualify as artificial moral experts and we would have good ethical reasons to use them. (shrink)

The recent literature on epistemic injustice has convincingly showed that injustice is often self-concealing, because those who suffer it lack the hermeneutical resources to talk about it. How, then, are the victims of epistemic injustice capable of denouncing and resisting it? The article seeks an answer to this question by inquiring into what Judith Shklar calls the “sense of injustice.” Following Shklar, I argue that the identification and critique of injustice relies on feeling rather than established moral values. In order (...) to clarify how feelings can be the source of universal claims, I turn to an interpreta - tion of Kant’s analysis of the feeling of the sublime developed by Jean-François Lyotard. According to this interpretation, any act of communication generates a silence that calls to be expressed. Following this view, I argue that epistemic injustice leads to a universalist act of epistemic resistance on the basis of the feeling that silenced voices ought to be head. (shrink)

Categorization and memory for specific items are fundamental processes that allow us to apply knowledge to novel stimuli. This study directly compares categorization and memory using delay match to category (DMC) and delay match to sample (DMS) tasks. In DMC participants view and categorize a stimulus, maintain the category across a delay, and at the probe phase view another stimulus and indicate whether it is in the same category or not. In DMS, a standard item working memory task, participants encode (...) and maintain a specific individual item, and at probe decide if the stimulus is an exact match or not. Constrained Principal Components Analysis was used to identify and compare activity within neural networks associated with these tasks, and we relate these networks to those that have been identified with resting state-fMRI. We found that two frontoparietal networks of particular interest. The first network included regions associated with the dorsal attention network and frontoparietal salience network; this network showed patterns of activity consistent with a role in rapid orienting to and processing of complex stimuli. The second uniquely involved regions of the frontoparietal central executive network; this network responded more slowly following each stimulus and showed a pattern of activity consistent with a general role in role in decision-making across tasks. Additional components were identified that were associated with visual, somatomotor and default mode networks. (shrink)

Many people think that citizenship should not be for sale. On their view, it is morally wrong for states to sell citizenship to foreigners. In this article, I challenge this view. I argue that it is in principle permissible for states to sell citizenship. I contend that, if states can permissibly deny foreigners access to citizenship in some cases, then states can permissibly give foreigners the option of buying citizenship in these cases. Furthermore, I defend the permissibility of selling citizenship (...) against the objections that selling citizenship values citizenship in the wrong way, corrupts civic norms, and unfairly discriminates against poor foreigners. I conclude by noting that, although selling citizenship is not intrinsically wrong, it could still be wrong for states to sell citizenship in practice. If existent immigration restrictions are unjust, then it may be impermissible for states to sell citizenship in the real world. (shrink)

The subtraction argument, originally put forward by Thomas Baldwin (1996), is intended to establish Metaphysical Nihilism, the thesis that there could have been no concrete objects. Some modified versions of the argument have been proposed in order to avoid some difficulties faced by the original argument. In this paper I shall concentrate on two of those versions, the so-called subtraction argument* (presented and defended in Rodriguez-Pereyra 1997, 2000, 2002), and Efird and Stoneham’s recent version of the argument (Efird and Stoneham (...) 2005). I shall defend the subtraction argument* from Alexander Paseau’s (2006) objection that because a crucial premise of the subtraction argument* may have no plausibility independent from Metaphysical Nihilism, the subtraction argument* is not suasive. Although Paseau focuses on the subtraction argument*, I shall point out that Efird and Stoneham could reply to Paseau’s objection in the same way. Thus there are (at least) two suasive versions of the subtraction argument that establish Metaphysical Nihilism. But are those two arguments equally good? I shall argue that the subtraction argument* is preferable to Efird and Stoneham’s argument. (shrink)

Mellor´s theory of causation has two components, one according to which causes raise their effects´ chances, and one according to which causation links facts. I argue that these two components are not independent from each other and, in particular, that Mellor´s thesis that causation links facts requires his thesis that causes raise their effects´ chances, since without the latter thesis Mellor cannot stop the slingshot argument, an argument that is a threat to any theory postulating facts as the relata of (...) causation. (shrink)

The paper argues that grounding is neither irreflexive, nor asymmetric, nor transitive. In arguing for that conclusion the paper also arguesthat truthmaking is neither irreflexive, nor asymmetric, nor transitive.