OBJETIVO -/- O estudante de Zootecnia e de Veterinária, quando se depara com a produção animal, um dos pilares importantes é a reprodução, uma vez que é a perpetuação da espécie, seja para gerar filhas de uma vaca campeã em produção leiteira e de um touro com rusticidade e com aptidão produtiva de corte, ou mesmo para reposição de um plantel, o mesmo deve estar consciente de que esse ramo é de extrema responsabilidade, já que estará intimamente lidando com a (...) vida e com um investimento que pode gerar lucros em demasia para a propriedade ou, se mal feito o manejo da reprodução, trazer sérios transtornos para a mesma. -/- Nesse trabalho, o estudante revisará os sucessos da puberdade e estacionalidade reprodutiva relacionando-os com os processos endócrinos e os fatores que afetam sua manifestação como os nutricionais, para compreender a maneira ao qual podem ser manipuladas. -/- -/- • _____INTRODUÇÃO -/- A puberdade marca o início da vida reprodutiva do animal, permitindo integrar o indivíduo ao seu ciclo produtivo. A estacionalidade é uma característica de adaptação que algumas espécies desenvolveram para fazer garantir a eficiência da reprodução e a sobrevivência dos filhotes. -/- -/- • _____PUBERDADE -/- A puberdade é atingida quando o animal é capaz de produzir e liberar gametas viáveis e funcionais (férteis). Na fêmea esse fato ocorre na primeira ovulação, que geralmente coincide com a manifestação do comportamento do cio; e nos machos durante a primeira ejaculação com espermatozoides viáveis. -/- Do ponto de vista da produção animal, puberdade prematura ou precoce, é importante para poder permitir a incorporação dos animais ao ciclo produtivo o mais rapidamente possível. No caso de touros holandeses, por exemplo, é desejável que produzam sêmen precocemente para incorporá-los a prova de progênie; nas fêmeas, entretanto, deve-se considerar que nem sempre é conveniente usar o primeiro ciclo ou cio para reprodução. É o caso das marrãs (porcas primíparas), onde é benéfico esperar até o segundo ou terceiro estro para aumentar o tamanho da ninhada. Também pode ser vantajoso esperar que o indivíduo alcance sua maturidade sexual, que ocorre quando a fêmea consegue se reproduzir sem sofrer efeitos adversos. A ovelha nascida na primavera, por exemplo, pode engravidar no outono seguinte e dar à luz no primeiro ano de vida, mas seu crescimento pode ser afetado; o mesmo ocorre com a novilha, em que o acasalamento precoce pode promover distorcia por falta de desenvolvimento pélvico. -/- A puberdade é um processo gradual e está intimamente relacionada à taxa de crescimento e ao metabolismo energético. O recém-nascido usa energia para funções vitais, principalmente termorregulação; esse feito se deve ao fato de os jovens possuírem uma superfície corporal muito elevada em relação ao seu volume. Durante o desenvolvi-mento subsequente dos tecidos também há prioridade no uso de nutrientes, que inicialmente favorecem o desenvolvimento do tecido ósseo e muscular, e uma vez que estes atingem determinado tamanho de acordo com as condições genéticas do indivíduo, inicia-se o desenvolvimento do tecido adiposo, que é indicativa de um reservatório de energia. É importante ressaltar que existe uma interação entre a genética e o meio ambiente, de forma que o potencial genético só será expresso se o meio ambiente for favorável. -/- Para que a ovulação ocorra, é necessário considerar o funcionamento do eixo hipotálamo-hipófise-gonodal. O aumento da frequência pulsátil do GnRH hipotalâmico e em consequência do LH hipofisário provoca a maturação do folículo em nível gonodal, o que aumenta a produção de estrógenos. O aumento dos estrogênios causa, por feedback positivo no hipotálamo, a liberação do pico pré-ovulatório de LH e, consequentemente, a ovulação. Na fase pré-púbere, a frequência dos pulsos de GnRH e LH é muito baixa e insuficiente para provocar a maturação folicular, pois o hipotálamo é inibido e, portanto, não ocorre ovulação. -/- A geração pulsátil de GnRH no momento reprodutivo adequado para desencadear o início da puberdade depende de uma rede neural complexa que, além dos neurônios GnRH, inclui outros neurônios e células da glia; ele também integra vários sinais internos e externos para o corpo. A morfologia dos neurônios GnRH também é única, uma vez que seus dendritos também podem funcionar como axônios, dando-lhes uma função distinta. A geração de pulsos também indica a necessidade de sincronização entre subpopulações de neurônios GnRH, que, acima de tudo, parece ser extrínseca a esses neurônios e envolve múltiplos hormônios e neurotransmissores -/- Se dois níveis de conexões aferentes são considerados, estima-se que cada neurônio de GnRH pode ser conectado a cerca de cinco milhões de outros neurônios; milhares de genes, então, podem estar envolvidos no processo da puberdade. A importância funcional e hierárquica de cada um desses genes no controle dos neurônios GnRH, juntamente com outros fatores neuronais e gliais, pode diferir entre as espécies. Existem, no entanto, componentes fundamentais que parecem ser comuns a todos os mamíferos e que se situam nos níveis hierárquicos mais elevados, ajudando a compreender a progressão do processo puberal. Assim, todas as espécies de mamíferos estudadas, por exemplo, têm aglomerados de neurônios kisspeptinérgicos (que secretam kisspeptina), envolvidos na regulação da secreção tônica e secreção cíclica de GnRH, que também se classifica como o elemento mais alto na hierarquia desse complexo neuronal após considerar os neurônios GnRH. -/- Sabe-se que o eixo hipotálamo-hipofisário-gonodal está ativo desde as primeiras fases da vida do indivíduo, mesmo antes do nascimento em certas espécies. A secreção de GnRH, no entanto, é suprimida mais tarde no desenvolvimento e permanece dessa forma até o período pré-púbere, quando será reativada gradualmente. -/- Por várias décadas, a supressão e reinicialização dos pulsos de GnRH foi atribuída a uma hipótese conhecida como teoria gonadostat que afirma que o centro tônico do hipotálamo é inibido devido à sua sensibilidade ao mecanismo de feedback negativo dos esteroides gonodais, é aumentado; portanto, o GnRH e a consequente secreção de gonadotrofinas (FSH e LH) são insuficientes para a ocorrência da maturação folicular e espermatogênese. Essa sensibilidade diminui progressivamente à medida que a puberdade se aproxima. -/- Sabe-se agora que existem fatores não gonodais que agem em paralelo com os esteroides para mediar mudanças no feedback negativo que também são específicos da espécie. -/- Na fêmea, o centro gerador de pulso cíclico também deve ser considerado, o qual é responsável por iniciar a primeira ovulação. O centro cíclico é composto por uma segunda subpopulação de neurônios GnRH que é reativada por meio de uma complexa interação entre vários sistemas neuronais inibitórios (que devem reduzir progressiva-mente sua influência) e outros sistemas excitatórios, que, por sua vez, operam por meio de diferentes neurotransmissores, como o ácido γ-amino-butírico (GABA) e seus receptores, glutamato, óxido nítrico e neuropeptídio Y (NPY). Esses fatores, juntamente com as alterações morfológicas observadas nos neurônios do GnRH à medida que a puberdade se aproxima, e com as interações e sinais aferentes das células gliais, levam a um padrão de progressão linear que culminará na reativação do centro cíclico. Esse processo era conhecido anteriormente como teoria da maturação central e faz parte das mudanças que configuram o processo para chegar à puberdade. A elevação nas concen-trações de estradiol subsequente à reativação gradual do centro gerador de pulso tônico GnRH provavelmente permitirá a maturação final do centro cíclico. -/- A forma como cada organismo estabelece o momento certo para iniciar as mudanças que levam à puberdade é conhecido; a existência de algum mecanismo neurobiológico que constitui um relógio interno pode ser considerada. No entanto, esse mecanismo afetaria principalmente o desenvolvimento neuronal no nível central; também seria difícil compará-lo com a maneira pela qual fatores externos ao indivíduo afetam o início da puberdade. Nessa perspectiva, um sistema que permita receber informações completas sobre o crescimento e desenvolvimento do indivíduo poderia ser mais prático. Os mediadores desse sistema incluem o hormônio do crescimento, IGF-I, leptina e outros substratos metabólicos. A leptina em particular, que sinaliza as reservas de tecido adiposo, é um dos elementos mais importantes e, embora não determine quando começa a puberdade, se atua como fator permissivo para que o processo progrida, uma vez que excede um nível limite. A consideração do estágio de desenvolvimento do animal para o início da puberdade era anteriormente conhecida como o peso corporal crítico ou teoria do lipostato. É importante considerar que as três teorias mencionadas não são exclusivas. -/- O mecanismo da puberdade nos machos é semelhante ao já descrito; entretanto, deve-se lembrar que no macho o centro cíclico não está ativo. À medida que a puberdade se aproxima, o crescimento testicular é desencadeado e, em ruminantes e suínos, o pênis que estava preso à mucosa prepucial é gradualmente liberado. -/- -/- • _____FATORES QUE INFLUENCIAM A PUBERDADE -/- Os animais podem manifestar a puberdade de três formas diferentes. Pode ser tardia e o animal demorar para estar apto a reprodução; precoce e o animal entrar na vida reprodutiva antes do esperado ou pode ser normal e o animal estar com boa conformação e idade. Para tanto, alguns fatores podem interferir à manifestação da puberdade pelos animais como a genética, idade e peso, nutrição, fotoperíodo e o próprio manejo adotado. -/- -/- Genética -/- O genótipo afeta a idade da puberdade, pois algumas raças são anteriores a outras. Nos bovinos, as raças europeias atingem a puberdade antes dos zebuínos, isto é, uma novilha ou novilho da raça holandesa atinge a puberdade primeiro que os animais da mesma idade e do mesmo peso da raça nelore, por exemplo. -/- Da mesma forma, as porcas da raça chinesa Meishan atingem a puberdade por volta dos 115 dias de idade, metade da idade das raças brancas. As ovelhas de raças de corte, da mesma forma, são mais precoces que os produtores de lã. As raças pequenas, da mesma forma, são geralmente mais precoces, pelo menos em bovinos (jersey x guzerá) e em caninos. Os híbridos, por outro lado, apresentam puberdade mais precoce que os puros, devido ao efeito da heterose. Por este motivo, em certas espécies são utilizadas linhas híbridas. -/- -/- Idade e peso -/- A tabela 1 mostra a idade média de início da puberdade em espécies domésticas. O peso vivo (PV) adulto é mais relevante para a idade na puberdade nos ruminantes, enquanto em suínos é menos decisivo. A tabela também apresenta a porcentagem de peso corporal necessária para a puberdade ocorrer de forma natural. -/- -/- Tabela 1: Idade e peso a puberdade das espécies domésticas -/- Espécie -/- Fêmea (meses) -/- Macho (meses) -/- PV adulto (%) -/- Gado holandês -/- 11 (8-15) -/- 11 (7-18) -/- 30-40 -/- Gado brahman -/- 19 -/- 17 -/- 45-60 -/- Caprinos e ovinos -/- 7 (4-14) -/- 7 (6-9) -/- 40-60 -/- Suínos -/- 6 (5-7) -/- 7 (5-8) -/- 75 -/- Equinos -/- 18 (12-19) -/- 14 (10-24) -/- - -/- Caninos -/- 12 (6-24) -/- 9 (5-12) -/- - -/- Felinos -/- 8 (4-12) -/- 9 (8-10) -/- - -/- Fonte: VALENCIA, 2018. -/- Nutrição -/- Como a puberdade está relacionada à taxa de crescimento, os animais que recebem uma nutrição adequada e balanceada apresentarão puberdade em uma idade mais jovem, ou seja, mais precocemente; ao contrário, a puberdade será tardia nos animais que sofreram restrição alimentar, que estão desnutridos ou que tiveram seu crescimento afetado por doenças infecciosas ou parasitárias. A superalimentação também não é recomendada, pois pode alterar tanto os sinais que são recebidos pelo hipotálamo quanto sua resposta a eles. -/- Logo, o manejo alimentar adotado deve estar de acordo com as normas estabeleci-das pelos especialistas na área, principalmente no tocante as exigências nutricionais que devem servir de regra na propriedade. Sendo assim, os animais entrarão em puberdade com as taxas de alta qualidade o que afetará positivamente na prole futura e dará retorno lucrativo ao proprietário. -/- -/- Época do ano (Fotoperíodo) -/- Em fêmeas de espécies sazonais, como ovelhas e cabras, existem certos requisitos de fotoperíodo que devem ser atendidos para que a puberdade ocorra. Nessas espécies, um período de exposição a dias longos é necessário, seguido por outro de exposição a dias curtos. Na verdade, os cordeiros e cabritos nascidos fora da estação, mesmo que tenham atingido o peso necessário, terão que esperar até o outono seguinte (a estação reprodutiva) para atingir a puberdade. Os machos, por outro lado, não estão sujeitos a essas limitações nos requisitos fotoperiódicos para apresentar a puberdade. -/- Em novilhas nascidas no outono, por outro lado, a puberdade ocorre antes de um ano de idade, no verão seguinte ou no início do outono, mais cedo do que nas nascidas na primavera, devido à exposição a longos dias durante os primeiros seis meses do ano após seu nascimento aceleram seu crescimento. Em gatos, o aumento do fotoperíodo também acelera o início da puberdade. -/- Em ovelhas e novilhas, a primeira ovulação que ocorre ao entrar na puberdade é silenciosa; ou seja, não é acompanhada de sinais comportamentais de cio como a micção frequente, inchamento da vulva, uma montando a outra e deixando-se montar etc., pois para que esse comportamento se manifeste, o sistema nervoso necessita de uma pré-sensibilização com progesterona que não estará presente até o próximo ciclo, após o desenvolvimento do corpo lúteo vindo desta primeira ovulação. -/- -/- Sociossexual -/- A interação de indivíduos da mesma espécie ou a presença ou ausência de sinais de bioestimulação, como feromônios, pode afetar o período de puberdade. A puberdade, por exemplo, é atrasada em porcas criadas individualmente em comparação com porcas criadas em grupo. Além disso, na porca, ovelha e cabra, a exposição ao macho estimula as fêmeas e a puberdade aparece mais precocemente. -/- -/- Manejo -/- Certas práticas de manejo podem acelerar a puberdade, especialmente no período pré-púbere. Em porcas próximas à puberdade, por exemplo, o estresse causado por procedimentos, como o transporte de um local para outro ou a exposição ao macho, faz com que apareça o estro em torno de sete dias após a realização do manejo mencionado. -/- -/- • _____ESTACIONALIDADE REPRODUTIVA -/- A estacionalidade ou sazonalidade reprodutiva é uma estratégia evolutiva que se desenvolveu em algumas espécies; tende a tornar a reprodução mais eficiente. Nos países de latitudes distantes do equador, o objetivo é que as crias nasçam na primavera, época do ano mais favorável, graças à abundância de alimentos e às amenas condições climáticas. No caso da ovelha, cuja gestação dura cinco meses, para que os partos ocorram na primavera, ela deve engravidar no outono (figura 1), quando os dias são curtos; enquanto a égua, tendo uma gestação de aproximadamente 11 meses, deve conceber na primavera, quando os dias são longos; assim, o parto ocorrerá na primavera do ano seguinte (figura 2). -/- -/- Figura 1: Esquema ilustrativo da estacionalidade reprodutiva na espécie ovina. Fonte: PIRES et al., 2011. -/- -/- Esta característica evolutiva desenvolvida pela seleção natural na maioria das espécies silvestres e ainda é conservado por algumas espécies domésticas, como ovelhas, cabras, cavalos e gatos. Em bovinos e suínos, ao contrário, a domesticação levou à perda quase total da estacionalidade reprodutiva. -/- A estacionalidade reprodutiva é codificada nos genes; significa então que a seleção natural favoreceu a propagação de genes que permitiam acoplar a hora do nascimento com a melhor época do ano, por isso passou a ser considerada um método anticoncepcional natural. -/- -/- Figura 2: ciclo reprodutivo anual em espécies estacionais; onde são apresentados os períodos de gestação e a forma como se agrupam os nascimentos, independentemente da época reprodutiva da espécie, em vermelho as fêmeas estão apresentando estro ou cio. Fonte: VALENCIA, 2018. -/- -/- Fotoperíodo -/- Para sincronizar o período fértil com a época mais favorável do ano, a maioria das espécies sazonais usa o fotoperíodo (quantidade de luz diária ao longo do ano). -/- Este sinal ambiental é seguro, confiável e se repete a cada ano. Ovinos e caprinos se reproduzem na época do ano em que os dias são curtos e os equinos quando são longos. O grau de sazonalidade depende da origem da raça. As raças nativas de países localizados em latitudes elevadas (> 50°,ovelhas: soay, blackface, suffolk; cabras: saanen, alpino francês, toggenburg; equinos: puro-sangue, hanoveriano) terão uma estacionalidade mais acentuada do que as latitudes menores ou mediterrâneas (ovelhas: merino; cabras: murciana granadina; equinos: quarto de milha). Também existem raças de latitudes próximas ao Equador cuja estacionalidade é baixa ou nula (ovelhas: raças de pelo, crioulas; cabras: raças africanas e asiáticas) (tabela 2). -/- Para a maioria das raças de ovinos e caprinos, a estação reprodutiva começa no final do verão e início do outono; caracteriza-se pela apresentação de ciclos estrais sucessivos, e termina no final do inverno, quando se inicia o anestro, que se caracteriza pela ausência de ovulação. Nos equinos, ocorre o contrário, uma vez que a estação reprodutiva ocorre na primavera e no verão. -/- -/- Tabela 2: Relação entre a origem da raça e o grau de estacionalidade ou sazonalidade -/- Espécie -/- Alta -/- Média -/- Baixa -/- Ovinos -/- Suffolk, raças britânicas de lã e corte -/- Merino -/- Pelibuey, crioulas -/- Caprinos -/- Saanen, alpino, toggenburg -/- Murciana granadina -/- Crioula -/- Equinos -/- Puro-sangue, hanoveriano, quarto de milha -/- - -/- Crioula, burros -/- Fonte: VALENCIA, 2018. -/- -/- Mecanismo neuroendócrino da estacionalidade -/- Durante o período de anestro, o fotoperíodo exerce efeito inibitório sobre o centro tônico do GnRH no hipotálamo, diminuindo a frequência de pulso. Consequentemente, a pulsatilidade do LH também diminui, que agora é incapaz de induzir a maturação folicular, o aumento dos estrogênios, o pico pré-ovulatório de LH e, portanto, a ovulação. -/- Isso ocorre porque durante o anestro a sensibilidade do hipotálamo ao mecanismo de feedback negativo dos estrogênios e de outros fatores de origem não gonodal é aumentada. Ao aproximar-se da estação reprodutiva, a sensibilidade hipotalâmica diminui e o aumento da pulsatilidade do GnRH causa as mudanças que culminam na ovulação. Portanto, o mecanismo endócrino do anestro estacional é semelhante ao do anestro pré-púbere e de alguns outros tipos de anestro. -/- A estacionalidade é um bom exemplo da interação entre o meio ambiente e o sistema neuroendócrino, pois o organismo é capaz de traduzir um sinal externo ambiental, como o fotoperíodo, em um sinal hormonal interno, que neste caso é a melatonina. -/- A glândula pineal secreta melatonina durante as horas de escuridão. Os animais sazonais apresentam um ritmo reprodutivo endógeno, que é regulado por janelas de fotossensibilidade, determinadas por mudanças na duração do dia. O sinal luminoso é captado pela retina e conduzido, via nervo, pelo trato retino-hipotalâmico até o núcleo supraquiasmático, que funciona como o relógio biológico do corpo. Daí o sinal viaja para o núcleo para-ventricular, depois para o gânglio cervical e, finalmente, para a glândula pineal, que responde secretando melatonina (figura 3). -/- Nas ovelhas, a estação reprodutiva começa quando a duração do dia diminui e, naturalmente, a noite aumenta; na égua, ocorre quando os dias se alongam. -/- A primavera não é necessariamente a melhor época do ano em todas as regiões do globo. Nas latitudes tropicais, a primavera coincide com a seca e não com a abundância de forragem, aspecto a ser levado em consideração ao programar a reprodução. -/- Outro ponto importante a considerar é que as raças europeias sazonais mantêm sua estacionalidade no Brasil. -/- -/- Figura 3: Mecanismo do fotoperíodo em ovinos e a melatonina. Fonte: HAFEZ, 2004. -/- -/- Estacionalidade no macho -/- O macho é menos afetado que a fêmea pelas mudanças típicas de cada época do ano, já que sua função reprodutiva não é necessariamente interrompida durante o anestro ou repouso sexual, embora a produção de hormônios reprodutivos, tamanho e tônus testicular, a libido, as características qualitativas e quantitativas do ejaculado e a fertilidade do esperma podem ser diminuídas. O nível de afetação depende do grau de sazonalidade da raça e da latitude. 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CRC Press, 2001. -/- HAFEZ, Elsayed Saad Eldin; HAFEZ, Bahaa. Reprodução animal. São Paulo: Manole, 2004. -/- HUGHES, P. E.; PHILIP, G.; SISWADI, R. The effects of contact frequency and transport on the efficacy of the boar effect. Animal Reproduction Science, v. 46, n. 1-2, p. 159-165, 1997. -/- KARSCH, FRED J. et al. Neuroendocrine basis of seasonal reproduction. In: Proceedings of the 1983 Laurentian Hormone Conference. Academic Press, 1984. p. 185-232. -/- LINCOLN, G. A.; SHORT, R. V. Seasonal breeding: nature's contraceptive. In: Proceedings of the 1979 Laurentian Hormone Conference. Academic Press, 1980. p. 1-52. -/- MELLO, Raquel Rodrigues Costa. Puberdade e maturidade sexual em touros bovinos. Agropecuária Científica no Semiárido, v. 10, n. 3, p. 11-28, 2015. -/- MEZA‐HERRERA, C. A. et al. Neuroendocrine, metabolic and genomic cues signalling the onset of puberty in females. Reproduction in Domestic Animals, v. 45, n. 6, p. e495-e502, 2010. -/- MONTEIRO, Claudia Dias; BICUDO, Sony Dimas; TOMA, Hugo Shisei. Puberdade em fêmeas ovinas. Pubvet, v. 4, p. Art. 850-857, 2010. -/- OLIVEIRA, Daniel de Jesus Cardoso de. Mecanismos neuroendócrinos envolvidos na puberdade de novilhas da raça Nelore. 2006. Tese de Doutorado em Medicina Veterinária. Universidade de São Paulo. -/- OLSTER, DEBORAH H.; FOSTER, DOUGLAS L. Control of gonadotropin secretion in the male during puberty: a decrease in response to steroid inhibitory feedback in the absence of an increase in steroid-independent drive in the sheep. Endocrinology, v. 118, n. 6, p. 2225-2234, 1986. -/- PIRES, Bruno Carlos et al. Métodos para elevar o ritmo reprodutivo dos ovinos. PUBVET, Londrina, V. 5, N. 11, Ed. 158, Art. 1071, 2011. -/- PLANT, Tony M.; ZELEZNIK, Anthony J. (Ed.). Knobil and Neill's physiology of reproduction. New York: Academic Press, 2014. -/- RAMIREZ, Domingo V.; MCCANN, S. M. Comparison of the regulation of luteinizing hormone (LH) secretion in immature and adult rats. Endocrinology, v. 72, n. 3, p. 452-464, 1963. -/- ROSER, JANET F.; HUGHES, JOHN P. Seasonal effects on seminal quality, plasma hormone concentrations, and GnRH‐induced LH response in fertile and subfertile stallions. Journal of andrology, v. 13, n. 3, p. 214-223, 1992. -/- SALOMONI, Eduardo et al. Idade e peso à puberdade em fêmeas de corte puras e cruzas em campo natural. Pesquisa Agropecuária Brasileira, v. 23, n. 10, p. 1171-1179, 1988. -/- SMITH, Jeremy T.; CLARKE, Iain J. Seasonal breeding as a neuroendocrine model for puberty in sheep. Molecular and cellular endocrinology, v. 324, n. 1-2, p. 102-109, 2010. -/- VALENCIA, J. Pubertad y estacionalidad reproductiva. In. PORTA, L. R.; MEDRANO, J. H. H. Fisiología reproductiva de los animales domésticos. Cidade do México: FMVZ-UNAM, 2018. -/- WHITTEMORE, Colin et al. The science and practice of pig production. Blackwell Science Ltd, 1998. -/- -/- -/- FIXAÇÃO DO ASSUNTO -/- -/- 1. Defina o que é puberdade e como ela manifesta-se no corpo. -/- -/- -/- 2. Diferencie puberdade de maturidade sexual. -/- -/- -/- 3. Quais são os fenômenos que devem ser observados em fêmeas que estão entrando na puberdade? -/- -/- -/- 4. Qual o papel do GnRH e do IGF-I sobre a puberdade? -/- 5. Um produtor possui duas ovelhas e um carneiro reprodutor, as ovelhas possuem idade e peso, mas não manifestaram seu primeiro cio, quais elementos que você recomenda ao produtor para induzir a ciclicidade dessas fêmeas? -/- -/- -/- 6. De forma geral, quais os fatores que podem afetar a entrada na puberdade dos animais? -/- -/- -/- 7. Defina estacionalidade reprodutiva. -/- -/- -/- 8. O que é fotoperíodo e qual sua importância para a reprodução dos animais domésticos? -/- -/- -/- 9. Defina as relações existentes entre a origem da raça e o grau de estacionalidade e como tais teorias se aplicam ao rebanho brasileiro. -/- -/- -/- 10. Qual o papel da glândula pineal para a estacionalidade reprodutiva? -/- -/- -/- 11. Por que os machos são menos afetados pela sazonalidade reprodutiva do que as fêmeas? -/- -/- -/- 12. Sabendo-se sobre os termos de puberdade e estacionalidade e as características de ambos nas espécies domésticas, pede-se: um criador deseja obter 5 novas crias ovinas e 5 caprinas em seu plantel até o final do ano, para tanto ele ainda possui um ano e está na estação do verão, sabendo-se sobre a estacionalidade dessas espécies elabore um projeto reprodutivo de modo que essas 10 fêmeas possam gerar uma cria cada até a primavera. -/- -/- Dados: 10 fêmeas gerando 10 crias. 1 macho ovino e 1 caprino. Fêmeas com 1 ano de idade (2º cio) e peso corporal = 55% do peso adulto. Verão de 2020 para parir na primavera de 2020. (shrink)

The rise of experimental philosophy has placed metaphilosophical questions, particularly those concerning concepts, at the center of philosophical attention. X-phi offers empirically rigorous methods for identifying conceptual content, but what exactly it contributes towards evaluating conceptual content remains unclear. We show how x-phi complements Rudolf Carnap’s underappreciated methodology for concept determination, explication. This clarifies and extends x-phi’s positive philosophical import, and also exhibits explication’s broad appeal. But there is a potential problem: Carnap’s account of explication was limited to empirical and (...) logical concepts, but many concepts of interest to philosophers are essentially normative. With formal epistemology as a case study, we show how x-phi assisted explication can apply to normative domains. (shrink)

Artificial intelligence (AI) is expected to revolutionise the practice of medicine. Recent advancements in the field of deep learning have demonstrated success in variety of clinical tasks: detecting diabetic retinopathy from images, predicting hospital readmissions, aiding in the discovery of new drugs, etc. AI’s progress in medicine, however, has led to concerns regarding the potential effects of this technology on relationships of trust in clinical practice. In this paper, I will argue that there is merit to these concerns, since AI (...) systems can be relied on, and are capable of reliability, but cannot be trusted, and are not capable of trustworthiness. Insofar as patients are required to rely on AI systems for their medical decision-making, there is potential for this to produce a deficit of trust in relationships in clinical practice. (shrink)

The Uniform Determination of Death Act (UDDA) provides that “an individual who has sustained either (1) irreversible cessation of circulatory and respiratory functions or (2) irreversible cessation of all functions of the entire brain, including the brain stem, is dead.” We show that the UDDA contains two conflicting interpretations of the phrase “cessation of functions.” By one interpretation, what matters for the determination of death is the cessation of spontaneous functions only, regardless of their generation by artificial means. By the (...) other, what matters is the cessation of both spontaneous and artificially supported functions. Because each UDDA criterion uses a different interpretation, the law is conceptually inconsistent. A single consistent interpretation would lead to the conclusion that conscious individuals whose respiratory and circulatory functions are artificially supported are actually dead, or that individuals whose brain is entirely and irreversibly destroyed may be alive. We explore solutions to mitigate the inconsistency. (shrink)

Serious actualism is the view that it is metaphysically impossible for an entity to have a property, or stand in a relation, and not exist. Fine (1985) and Pollock (1985) influentially argue that this view is false. In short, there are properties like the property of nonexistence, and it is metaphysically possible that some entity both exemplifies such a property and does not exist. I argue that such arguments are indeed successful against the standard formulation of serious actualism. However, I (...) also argue that we should distinguish a weaker formulation of serious actualism using the actualist distinction between truth in, and truth at, a possible world. This weaker formulation is then shown to be consistent with the existence and possible exemplification of properties like the property of nonexistence. I end with a novel argument for the truth of the weaker formulation. (shrink)

In the past few years there has been a turn towards evaluating the empirical foundation of epistemic contextualism using formal (rather than armchair) experimental methods. By-and-large, the results of these experiments have not supported the original motivation for epistemic contextualism. That is partly because experiments have only uncovered effects of changing context on knowledge ascriptions in limited experimental circumstances (when contrast is present, for example), and partly because existing experiments have not been designed to distinguish between contextualism and one of (...) its main competing theories, subject-sensitive invariantism. In this paper, we discuss how a particular, "third-person", experimental design is needed to provide evidence that would support contextualism over subject-sensitive invariantism. In spite of the theoretical significance of third-person knowledge ascriptions for debates surrounding contextualism, no formal experiments evaluating such ascriptions that assess contextualist claims have previously been conducted. In this paper, we conduct an experiment specifically designed to examine that central gap in contextualism’s empirical foundation. The results of our experiment provide crucial support for epistemic contextualism over subject-sensitive invariantism. (shrink)

It is now well-known that Newton–Cartan theory is the correct geometrical setting for modelling the quantum Hall effect. In addition, in recent years edge modes for the Newton–Cartan quantum Hall effect have been derived. However, the existence of these edge modes has, as of yet, been derived using only orthodox methodologies involving the breaking of gauge-invariance; it would be preferable to derive the existence of such edge modes in a gauge-invariant manner. In this article, we employ recent work by Donnelly (...) and Freidel in order to accomplish exactly this task. Our results agree with known physics, but afford greater conceptual insight into the existence of these edge modes: in particular, they connect them to subtle aspects of Newton–Cartan geometry and pave the way for further applications of Newton–Cartan theory in condensed matter physics. (shrink)

Colour relationalism holds that the colours are constituted by relations to subjects. Anti-relationalists have claimed that this view stands in stark contrast to our phenomenally-informed, pre-theoretic intuitions. Is this claim right? Cohen and Nichols’ recent empirical study suggests not, as about half of their participants seemed to be relationalists about colour. Despite Cohen and Nichols’ study, we think that the anti-relationalist’s claim is correct. We explain why there are good reasons to suspect that Cohen and Nichols’ experimental design skewed their (...) results in favour of relationalism. We then run an improved study and find that most of our participants seem to be anti-relationalists. We find some other interesting things too. Our results suggest that the majority of ordinary people find it no less intuitive that colours are objective than that shapes are objective. We also find some evidence that when those with little philosophical training are asked about the colours of objects, their intuitions about colour and shape cases are similar, but when asked about people’s colour ascriptions, their intuitions about colour and shape cases differ. (shrink)

Propositional contingentism is the view that what propositions there are is a contingent matter—certain propositions ontologically depend on objects which themselves only contingently exist. Possible worlds are, loosely, complete ways the world could have been. That is to say, the ways in which everything in its totality could have been. Propositional contingentists make use of possible worlds frequently. However, a neglected, but important, question concerns whether there are any notions of worlds which are both theoretically adequate and consistent with propositional (...) contingentism. Some notion of a possible world is adequate if the systematic connection between, at least, possibility and truth at some possible world holds. Here, I argue that no adequate notion of a possible world is available to at least those who subscribe to one natural formulation of propositional contingentism. I also show that this result contrasts with a simple and adequate definition of a possible world available to the necessitist—those who hold that necessarily everything necessarily exists. (shrink)

This paper describes a neglected aspect of the critique of academic ‘cultures of speed’ offered by Maggie Berg and Barbara Seeber in The Slow Professor. I argue internalisation of the values and imperatives of cultures of speed can encourage the erosion of a range of academic virtues while also facilitating the development of a range of academic vices. I focus on the ways that an internalised ‘psychology of speed’ erodes our capacity to exercise the virtues of intellectual beneficence – excellences (...) of character which advance the intellectual needs of others – by radically distorting our experience of time. (shrink)

In De Anima 2.4, Aristotle claims that nutritive soul encompasses two distinct biological functions: nutrition and reproduction. We challenge a pervasive interpretation which posits ‘nutrients’ as the correlative object of the nutritive capacity. Instead, the shared object of nutrition and reproduction is that which is nourished and reproduced: the ensouled body, qua ensouled. Both functions aim at preserving this object, and thus at preserving the form, life, and being of the individual organism. In each case, we show how Aristotle’s detailed (...) biological analysis supports this ontological argument. (shrink)

Serious actualists take it that all properties are existence entailing. I present a simple puzzle about sentence tokens which seems to show that serious actualism is false. I then consider the most promising response to the puzzle. This is the idea that the serious actualist should take ordinary property-talk to contain an implicit existential presupposition. I argue that this approach does not work: it fails to generalise appropriately to all sentence types and tokens. In particular, it fails to capture the (...) right distinctions we ought to make between what I call _typographical sentence types_—an interesting and previously undiscussed class of fine-grained sentence types which are partially individuated by their typography, or how they look when written out. (shrink)

If a person requires an organ or tissue donation to survive, many philosophers argue that whatever moral responsibility a biological relative may have to donate to the person in need will be grounded at least partially, if not entirely, in biological relations the potential donor bears to the recipient. We contend that such views ignore the role that a potential donor's unique ability to help the person in need plays in underwriting such judgments. If, for example, a sperm donor is (...) judged to have a significant moral responsibility to donate tissue to a child conceived with his sperm, we think this will not be due to the fact that the donor stands in a close biological relationship to the recipient. Rather, we think such judgments will largely be grounded in the presumed unique ability of the sperm donor to help the child due to the compatibility of his tissues and organs with those of the recipient. In this paper, we report the results of two studies designed to investigate the comparative roles that biological relatedness and unique ability play in generating judgments of moral responsibility in tissue donation cases. We found that biologically related individuals are deemed to have a significant moral responsibility to donate tissue only when they are one of a small number of people who have the capacity to help. (shrink)

This essay explores a theory of panoramas put forward by the experimental postwar German novelist and translator Arno Schmidt. Schmidt claims that panoramas were so pervasive in the visual culture of the nineteenth century that they unconsciously influenced writers of the period, so that when they wanted to describe vast landscapes they unthinkingly framed their descriptions by drawing on experience with specific panoramas. He primarily expounds the theory in his longest work of fiction, Zettel’s Traum (1970), translated as Bottom’s Dream (...) (2016), where he supports it with evidence from Edgar Allan Poe and Jules Verne. He also promoted the theory in later interviews, and regarded it not just as part of his fiction but as a significant discovery in its own right. This essay extracts Schmidt’s theory from its fictional context and illustrates how he thought it could be used hermeneutically to uncover submerged panoramas in the works of nineteenth century authors. We conclude by locating the theory as part of the contemporary reception history of panoramas. (shrink)

We show that early vision can use monocular cues to rapidly complete partially-occluded objects. Visual search for easily detected fragments becomes difficult when the completed shape is similar to others in the display; conversely, search for fragments that are difficult to detect becomes easy when the completed shape is distinctive. Results indicate that completion occurs via the occlusion-triggered removal of occlusion edges and linking of associated regions. We fail to find evidence for a visible filling-in of contours or surfaces, but (...) do find evidence for a "functional" filling-in that prevents the constituent fragments from being rapidly accessed. As such, it is only the completed structures—and not the fragments themselves—that serve as the basis for rapid recognition. (shrink)

Abstract: This paper traces a Kantian and pragmatist line of thinking that connects the ideas of conceptual content, object cognition, and modal constraints in the form of counterfactual sustaining causal laws. It is an idea that extends from Kant’s Critique of Pure Reason through C. I. Lewis’s Mind and the World-Order to the Kantian naturalism of Wilfrid Sellars and the analytic pragmatism of Robert Brandom. Kant put forward what I characterize as a modal conception of objectivity, which he developed as (...) an extended argument stretching from the transcendental deduction through the analogies of experience to the regulative maxims of reason and reflective judgment. In related ways in Lewis and Sellars, the very idea of an object of knowledge (and of intentionality more generally) is connected with a certain lawfulness or modal constraint the necessary representation of which, they argue, is an achievement of conceptualization. While Sellars agreed with the spirit of Lewis’s famous pragmatic conception of the a priori, Sellars’s conception of meaning and conceptual content differed in crucial ways with important consequences for this issue. I argue furthermore that a certain phenomenalist temptation threatens to spoil this insight both among some of Kant’s interpreters and in Lewis’s thought. Finally, I point out that Brandom’s “Kant-Sellars thesis” provides new support for this line of thought. Although questions concerning idealism continue to raise controversies for neo-Kantians and pragmatists, the line of thought itself represents a distinctive and still promising approach to questions concerning intentionality and conceptual content. (shrink)

In this paper we propose that our understanding of pathocentric epistemic injustices can be enriched if they are theorised in terms of predicaments. These are the wider socially scaffolded structures of epistemic challenges, dangers, needs, and threats experienced by ill persons due to their particular emplacement within material, social, and epistemic structures. In previous work we have described certain aspects of these predicaments - pathocentric epistemic injustices, pathophobia, and so on. We argue that thinking predicamentally helps us integrate the various (...) social, epistemic, and practical obstacles experienced by ill persons and also unify the many concepts available for theorising them (microaggessions, epistemic injustices, and so on). (shrink)

Many draw the distinction between truth in, and truth at, a possible world. The latter notion purportedly allows for propositions to be true relative to worlds even if they do not exist relative to those same worlds. Despite its wide application, the distinction is controversial. Some think that the notion of truth at a world is unintelligible. Here, I outline and discuss the most influential argument for the unintelligibility of truth at a world, The Picture Thinking Argument. I outline and (...) defend a neglected strategy to respond to this, arguing that if we take seriously the idea that possible worlds represent total ways the world could be, the distinction can be drawn intelligibly. (shrink)

Note: The paper attached here is a "pre-review" version, not the final version that has now been published online first at the link below. -/- In “Nothing is True,” Will Gamester defends a form of alethic nihilism that still grants truth-talk a kind of legitimacy: an expressive role that is implemented via a pretense. He argues that this view has all of the strengths of deflationism, while also providing an elegant resolution of the Liar Paradox and its kin. For the (...) alethic nihilist, Liar and related sentences are not true, and that is the end of the story. No contradiction arises because it does not thereby follow that any of these sentences are also true, since nothing is. Gamester concludes that the simplicity of this response to the semantic paradoxes makes alethic nihilism an attractive approach. We disagree. In addition to providing insurmountable obstacles for his form of alethic nihilism, we contend that a certain form of non-nihilist deflationism is better placed to deal with the paradoxes and to account for truth-talk more generally. (shrink)

Causal reasoning and game-theoretic reasoning are fundamental topics in artificial intelligence, among many other disciplines: this paper is concerned with their intersection. Despite their importance, a formal framework that supports both these forms of reasoning has, until now, been lacking. We offer a solution in the form of (structural) causal games, which can be seen as extending Pearl's causal hierarchy to the game-theoretic domain, or as extending Koller and Milch's multi-agent influence diagrams to the causal domain. We then consider three (...) key questions: i) How can the (causal) dependencies in games - either between variables, or between strategies - be modelled in a uniform, principled manner? ii) How may causal queries be computed in causal games, and what assumptions does this require? iii) How do causal games compare to existing formalisms? To address question i), we introduce mechanised games, which encode dependencies between agents' decision rules and the distributions governing the game. In response to question ii), we present definitions of predictions, interventions, and counterfactuals, and discuss the assumptions required for each. Regarding question iii), we describe correspondences between causal games and other formalisms, and explain how causal games can be used to answer queries that other causal or game-theoretic models do not support. Finally, we highlight possible applications of causal games, aided by an extensive open-source Python library. (shrink)

This essay is my review of Erwin Leiser’s excellent documentary film Germany Awake. This classic film first aired in Germany in 1968, and remains to this day one of the best surveys of major Nazi-era movies and exactly what messages they were meant to convey. The film underscores the emphasis the regime put on film as one of the premier mechanisms of propaganda, though Leiser’s film points out that most of the cinema produced by the Nazi regime was not pure (...) propaganda, but mainly entertainment. In the review, I put forward a list of criteria for evaluating the degree of the deceptiveness of propaganda, and why cinema is so apt to exploit those criteria. (shrink)

In the field of machine consciousness, it has been argued that in order to build human-like conscious machines, we must first have a computational model of qualia. To this end, some have proposed a framework that supports qualia in machines by implementing a model with three computational areas (i.e., the subconceptual, conceptual, and linguistic areas). These abstract mechanisms purportedly enable the assessment of artificial qualia. However, several critics of the machine consciousness project dispute this possibility. For instance, Searle, in his (...) Chinese room objection, argues that however sophisticated a computational system is, it can never exhibit intentionality; thus, would also fail to exhibit consciousness or any of its varieties. This paper argues that the proposed architecture mentioned above answers the problem posed by Searle, at least in part. Specifically, it argues that we could reformulate Searle’s worries in the Chinese room in terms of the three-stage artificial qualia model. And by doing so, we could see that the person doing all the translations in the room could realize the three areas in the proposed framework. Consequently, this demonstrates the actualization of self-consciousness in machines. (shrink)

The Mode of Relativity in Agrippa’s Five Modes does not fit with the other four modes, and disrupts an otherwise elegant system. We argue that it is not the familiar argument from epistemic relativism, but a formal condition on the structure of justifications: the principle that epistemic grounding relations cannot be reflexive. This understanding of Agrippan Relativity leads to a better understanding of the Modes of Hypothesis and Reciprocity, a clearer outline of the structure of Agrippa’s system as a whole, (...) and a new insight into the Two Modes that follow the Five. (shrink)

Disproof of heaven? -- Brain and gods -- The rational stance -- Reason and belief in God -- Against naturalism -- Atheism, inference, and IQ -- Atheism, autism, and intellectual humility -- Googling God -- Inference, intuition, and rationality.

A review article of Gillian Brock's Global Justice: A Cosmopolitan Account. Reviewed by Dara Salam. Public Reason, Vol.3, No.1, June 2011, pp. 114-117.

Confused terms appear to signify more than one entity. Carnap maintained that any putative name that is associated with more than one object in a relevant universe of discourse fails to be a genuine name. Although many philosophers have agreed with Carnap, they have not always agreed among themselves about the truth-values of atomic sentences containing such terms. Some hold that such atomic sentences are always false, and others claim they are always truth-valueless. Field maintained that confused terms can still (...) refer, albeit partially, and offered a supervaluational account of their semantic properties on which some atomic sentences with confused terms can be true. After outlining many of the most important theoretical considerations for and against various semantic theories for such terms, we report the results of a study designed to investigate which of these accounts best accords with the truth-value judgments of ordinary language users about sentences containing these terms. We found that naïve participants view confused names as capable of successfully referring to one or more objects. Thus, semantic theories that judge them to involve total reference failure do not comport well with patterns of ordinary usage. (shrink)

Biological order provided by α-helical secondary protein structures is an important resource exploitable by living organisms for increasing the efficiency of energy transport. In particular, self-trapping of amide I energy quanta by the induced phonon deformation of the hydrogen-bonded lattice of peptide groups is capable of generating either pinned or moving solitary waves following the Davydov quasiparticle/soliton model. The effect of applied in-phase Gaussian pulses of amide I energy, however, was found to be strongly dependent on the site of application. (...) Moving solitons were only launched when the amide I energy was applied at one of the α-helix ends, whereas pinned solitons were produced in the α-helix interior. In this paper, we describe a general mechanism that launches moving solitons in the interior of the α-helix through phase-modulated Gaussian pulses of amide I energy. We also compare the predicted soliton velocity based on effective soliton mass and the observed soliton velocity in computer simulations for different parameter values of the isotropy of the exciton-phonon interaction. The presented results demonstrate the capacity for explicit control of soliton velocity in protein α-helices, and further support the plausibility of gradual optimization of quantum dynamics for achieving specialized protein functions through natural selection. (shrink)

The essential biological processes that sustain life are catalyzed by protein nano-engines, which maintain living systems in far-from-equilibrium ordered states. To investigate energetic processes in proteins, we have analyzed the system of generalized Davydov equations that govern the quantum dynamics of multiple amide I exciton quanta propagating along the hydrogen-bonded peptide groups in α-helices. Computational simulations have confirmed the generation of moving Davydov solitons by applied pulses of amide I energy for protein α-helices of varying length. The stability and mobility (...) of these solitons depended on the uniformity of dipole-dipole coupling between amide I oscillators, and the isotropy of the exciton-phonon interaction. Davydov solitons were also able to quantum tunnel through massive barriers, or to quantum interfere at collision sites. The results presented here support a nontrivial role of quantum effects in biological systems that lies beyond the mechanistic support of covalent bonds as binding agents of macromolecular structures. Quantum tunneling and interference of Davydov solitons provide catalytically active macromolecular protein complexes with a physical mechanism allowing highly efficient transport, delivery, and utilization of free energy, besides the evolutionary mandate of biological order that supports the existence of such genuine quantum phenomena, and may indeed demarcate the quantum boundaries of life. (shrink)

Within contemporary philosophy of mind, it is taken for granted that externalist accounts of meaning and mental content are, in principle, orthogonal to the matter of whether cognition itself is bound within the biological brain or whether it can constitutively include parts of the world. Accordingly, Clark and Chalmers (1998) distinguish these varieties of externalism as ‘passive’ and ‘active’ respectively. The aim here is to suggest that we should resist the received way of thinking about these dividing lines. With reference (...) to Brandom’s (1994; 2000; 2008) broad semantic inferentialism, we show that a theory of meaning can be at the same time a variety of active externalism. While we grant that supporters of other varieties of content externalism (e.g., Putnam 1975 and Burge 1986) can deny active externalism, this is not an option for semantic inferentialists: On this latter view, the role of the environment (both in its social and natural form) is not ‘passive’ in the sense assumed by the alternative approaches to content externalism. (shrink)

The Introduction to the collection of papers, _Reflexivity: A Source-book in Self-reference_. The Introduction studies the limits of our understanding that we carry unavoidably with us. We are perpetually confined within the horizons of our conceptual structure. When this structure grows or expands, the breadth of our comprehensions enlarges, but we are forever barred from the wished-for glimpse beyond its boundaries, no matter how hard we try, no matter how much credence we invest in the substance of our learning and (...) mist of speculation. (shrink)

ABSTRACT: I examine how Meillassoux’s conception of correlationism in After Finitude, as I understand it, relates firstly to Kant’s transcendental idealist philosophy, and secondly to the analytic Kantianism of Wilfrid Sellars. I argue that central to the views of both Kant and Sellars is what might be called, with an ambivalent nod to Meillassoux, an objective correlationism. What emerges in the end as the recommended upshot of these analyses is a naturalistic Kantianism that takes the form of an empirical realism (...) in roughly Kant’s sense, but one that is happily wed with Sellars’ scientific realism, once the latter is disentangled from two implausible commitments that made such a reconciliation seem impossible to Sellars himself. (shrink)

This article focuses on a particular issue under machine ethics—that is, the nature of Artificial Moral Agents. Machine ethics is a branch of artificial intelligence that looks into the moral status of artificial agents. Artificial moral agents, on the other hand, are artificial autonomous agents that possess moral value, as well as certain rights and responsibilities. This paper demonstrates that attempts to fully develop a theory that could possibly account for the nature of Artificial Moral Agents may consider certain philosophical (...) ideas, like the standard characterizations of agency, rational agency, moral agency, and artificial agency. At the very least, the said philosophical concepts may be treated as signposts for further research on how to truly account for the nature of Artificial Moral Agents. (shrink)

The study focused on the Digital Technology (DT) Competency of Certified Public Accountants (CPAs) in Ilocos Sur. This study will be beneficial for the upskilling of CPAs in Ilocos Sur and serve as a guide to development of competency-based curriculum for accounting students and intervention programs by accounting professional organizations. Using a validated survey instrument, the researcher considered 107 CPAs that responded. Total enumeration was used. The survey investigated the CPAs’ level of digital technology along five competency domains. Descriptive method (...) of research was utilized Their level of DT Competency is interpreted as “Proficient”. The study hints that they are not so far behind in terms of digital competency, and they have an enormous potential in relation to IT utilization, management, administration, and risk management. Reassessment of the BS Accountancy curriculum, encouraging CPAs to take advance studies and future research in this line is recommended. CPAs in Ilocos Sur can optimistically adapt to the ever-changing demands of the workplace. (shrink)

This chapter describes some of the varieties of philosophical humanism and different conceptions of, and attitudes towards, the natural sciences. I focus on three kinds of humanism evident in 20th century European philosophy – humanism as essentialism, humanism as rational subjectivity, and existential humanism. Some are strongly allied to the sciences, others are antipathetic to them, while others offer subtler positions. By emphasising this diversity, I want to oppose claims about the inevitability of an 'alliance' of science to humanism, and (...) that claim that to be a humanist is something we must approve or applaud. At best, those 'alliances' and that praiseworthiness will only be true of certain varieties of humanism. (shrink)

Scholars are divided on the relationship between cynicism and political life. In this chapter, I describe and endorse what I call 'institutional cynicism' and suggest it can feature within kinds of virtuous civic stances in democratic societies. I accept that some forms of cynicism can be as destructive and as anti-democratic as critics insist. Institutional cynicism, of the sort I describe, can actually make us better citizens. It turns our attention towards sub-optimal aspects of the political institutions of democratic societies, (...) teaching us things about those institutions we need to know, without necessarily leading us into fatalism or despair. (shrink)

An internalist slogan says that justification depends on internal factors. But which factors are those? This paper examines some common motivations favoring internalism over externalism, and says they are compatible with including dispositional and even past mental states in the internal.

The extreme incidence and prevalence of rage-driven aggression and destructiveness in the United States is without parallel in any other industrialized country in the world. During 2022 alone, there were 647 mass shootings in the U.S. (in each, at least four victims were killed). Unfortunately these many killings comprise only one form of widespread rage in America. This paper seeks to answer why this is happening.

This paper, published in 2022 in the Social Epistemology Review and Reply Collective (SERRC), offers a philosopher-psychologist’s explanation of our species’ deeply rooted resistance to self-knowledge. The article focuses on limitations that come about when people do not possess a group of cognitive and psychological skills and competencies which the author has called “epistemological intelligence.” ¶¶¶¶¶ The paper develops the idea of “one-way concepts,” concepts that can appropriately and informatively be applied to the human species, but which, due to human (...) species pride and exemptionalism, people often refuse to do.¶¶¶¶¶ When people lack the necessary skills and competences, they become resistant to new ways of thinking which can help our species break free from self-limiting and often self-destructive ways patterns of thought and behavior.¶¶¶¶¶ . (shrink)

Starting with Kant’s undeveloped proposal of a “negative science,” the author describes how philosophy may be developed and strengthened by means of a systematic approach that seeks to identify and eliminate a widespread but seldom recognized form of systemic and propagating conceptual error. ¶¶¶¶¶ -/- The paper builds upon the author’s book, CRITIQUE OF IMPURE REASON: HORIZONS OF POSSIBILITY AND MEANING (Studies in Theory and Behavior, 2021). ¶¶¶¶¶ -/- The author’s purpose is twofold: first, to enable us to recognize the (...) boundaries of what is referentially forbidden—the limits beyond which reference becomes meaningless—and second, to avoid falling victims to a certain broad class of conceptual confusions that lie at the heart of many major philosophical problems. By realizing these objectives, the boundaries of possible meaning are determined. (shrink)

Macromolecular protein complexes catalyze essential physiological processes that sustain life. Various interactions between protein subunits could increase the effective mass of certain peptide groups, thereby compartmentalizing protein α-helices. Here, we study the differential effects of applied massive barriers upon the soliton-assisted energy transport within proteins. We demonstrate that excentric barriers, localized onto a single spine in the protein α-helix, reflect or trap three-spine solitons as effectively as concentric barriers with comparable total mass. Furthermore, wider protein solitons, whose energy is lower, (...) require heavier massive barriers for soliton reflection or trapping. Regulation of energy transport, delivery and utilization at protein active sites could thus be achieved through control of the soliton width, or of the effective mass of the protein subunits. (shrink)

Social machines are systems formed by technical and human elements interacting in a structured manner. The use of digital platforms as mediators allows large numbers of human participants to join such mechanisms, creating systems where interconnected digital and human components operate as a single machine capable of highly sophisticated behaviour. Under certain conditions, such systems can be described as autonomous and goal-driven agents. Many examples of modern Artificial Intelligence (AI) can be regarded as instances of this class of mechanisms. We (...) argue that this type of autonomous social machines has provided a new paradigm for the design of intelligent systems marking a new phase in the field of AI. The consequences of this observation range from methodological, philosophical to ethical. On the one side, it emphasises the role of Human-Computer Interaction in the design of intelligent systems, while on the other side it draws attention to both the risks for a human being and those for a society relying on mechanisms that are not necessarily controllable. The difficulty by companies in regulating the spread of misinformation, as well as those by authorities to protect task-workers managed by a software infrastructure, could be just some of the effects of this technological paradigm. (shrink)

Most explanations are either about events (why things happen), or about properties (why objects have the enduring characteristics that they do). Explanations of events have been studied extensively in philosophy and psychology, whereas the explanations of properties have received little or no attention in the literature. The present study is an exploration of the ways in which we explain various types of properties. Ten participants provided explanations of 45 properties by completing sentences of the form: “Xs have p because…” where (...) p is a property of the concept X. When coded into three traditional kinds of explanation (i.e. causal, purposive, categorical), nearly half of the explanations did not fit into any of these categories and were classified as “other”. Different patterns of preference for explanations emerged across the various property types for each domain. A qualitative analysis of the other kind revealed that the most frequent form of explanation involved another property of the object, as in ‘Xs have property p because they have property q”. Explanations of properties showed a homeostatic character. Simply relating two properties of a concept seems sufficient as an explanation of a property. (shrink)

In a recent Response published in the Journal of Medical Ethics,1 Buturovic provides two criticisms of my argument in ‘Is the exclusion of psychiatric patients from access to physician-assisted suicide discriminatory?’2 First, Buturovic argues that my argument effectively ‘erases the distinction between healthy adults and patients (whether somatic or psychiatric) essentially implying that PAS [physician-assisted suicide] should be available to all, for all reasons or, ultimately no reason’ (Buturovic,1 pg. 1). Second, Buturovic argues that opening the doors to medical assistance (...) in dying (MAID) for psychiatric patients could have a number of undesirable implications. In particular, Buturovic highlights the potential negative implications for relations of trust in medicine—psychiatry in particular—along with potential effects on the rate of organ donation. I would here like to respond to these two criticisms. In short, my response to Buturovic’s first argument is that the slope is not nearly as slippery as Buturovic suggests. The reason for this is that the plausibility of Buturovic’s argument rests on a significant misinterpretation of my argument, along with an important equivocation in her own. Buturovic argues that, under the three criteria that I propose for the provision of MAID—sufficient decision-making capacity, demonstrated treatment resistance, and a lack of substantially negative implications for existing standards of psychiatric treatment and research—the provision of MAID for trivial reasons, even no reason at all, is justifiable. The main problem with this argument is that I propose no such positive criteria. My argument is that none of the three arguments addressed in my previous paper are sufficient to justify the exclusion of any and all psychiatric patients from access to MAID. I do not claim, in other words, that any individual …. (shrink)

Protein α-helices provide an ordered biological environment that is conducive to soliton-assisted energy transport. The nonlinear interaction between amide I excitons and phonon deformations induced in the hydrogen-bonded lattice of peptide groups leads to self-trapping of the amide I energy, thereby creating a localized quasiparticle (soliton) that persists at zero temperature. The presence of thermal noise, however, could destabilize the protein soliton and dissipate its energy within a finite lifetime. In this work, we have computationally solved the system of stochastic (...) differential equations that govern the quantum dynamics of protein solitons at physiological temperature, T=310 K, for either a single isolated α-helix spine of hydrogen bonded peptide groups or the full protein α-helix comprised of three parallel α-helix spines. The simulated stochastic dynamics revealed that although the thermal noise is detrimental for the single isolated α-helix spine, the cooperative action of three amide I exciton quanta in the full protein α-helix ensures soliton lifetime of over 30 ps, during which the amide I energy could be transported along the entire extent of an 18-nm-long α-helix. Thus, macromolecular protein complexes, which are built up of protein α-helices could harness soliton-assisted energy transport at physiological temperature. Because the hydrolysis of a single adenosine triphosphate molecule is able to initiate three amide I exciton quanta, it is feasible that multiquantal protein solitons subserve a variety of specialized physiological functions in living systems. (shrink)

Cases of severe and enduring Anorexia Nervosa (SEAN) rightly raise a great deal of concern around assessing capacity to refuse treatment (including artificial feeding). Commentators worry that the Court of Protection in England & Wales strays perilously close to a presumption of incapacity in such cases (Cave and Tan 2017, 16), with some especially bold (one might even say reckless) observers suggesting that the ordinary presumption in favor of capacity ought to be reversed in such cases (Ip 2019). -/- Those (...) of us who worry that such trends and proposals amount to (or at least pose a serious threat of) wrongful discrimination on the grounds of disability nevertheless feel the pull of judging many SEAN service users to be incapacitous with respect to decisions regarding (perhaps amongst other things) treatments involving feeding, artificial or otherwise. But it is difficult to get to grips with exactly what their incapacity consists in. Many such service users seem able to understand, retain, use and weigh information, and express a decision (i.e. they seem, prima facie, to satisfy the ‘MacArthur’ criteria). At the very least, they do not, generally. (shrink)

[On Consciousness, Religion, and Freedom of the Will] An interview with Daniel Dennett on consciousness, religion and free will.