Minimum complexity integrated photonic architecture for delay-based reservoir computing.

Reservoir computing is an analog bio-inspired computation scheme for efficiently processing time-dependent signals, the photonic implementations of which promise a combination of massive parallel information processing, low power consumption, and high-speed operation. However, most of these implementations, especially for the case of time-delay reservoir computing, require extensive multi-dimensional parameter optimization to find the optimal combination of parameters for a given task. We propose a novel, largely passive integrated photonic TDRC scheme based on an asymmetric Mach-Zehnder interferometer in a self-feedback configuration, where the nonlinearity is provided by the photodetector, and with only one tunable parameter in the form of a phase shifting element that, as a result of our configuration, allows also to tune the feedback strength, consequently tuning the memory capacity in a lossless manner. Through numerical simulations, we show that the proposed scheme achieves good performance -when compared to other integrated photonic architectures- on the temporal bitwise XOR task and various time series prediction tasks, while greatly reducing hardware and operational complexity.

Múltiplos efeitos da pandemia de Covid-19 no contexto do transplante de órgãos no Brasil e no mundo / Multiple effects of the Covid-19 in the context of organ transplantation in Brazil and around the world

Introdução: Este artigo apresenta uma revisão literária do impacto dos transplantes de órgãos no contexto da pandemia de Covid-19. Esse período gerou desafios significativos para os programas de transplantes em todo o mundo, afetando a disponibilidade de órgãos, a segurança dos receptores, dos doadores e de recursos médicos. Objetivos: Realizar um levantamento dos aspectos relacionados aos impactos da pandemia de Covid-19 em torno do processo de transplantes. Método: Foi feita uma revisão sistemática com busca de artigos nas bases do PubMed, SciELO e LILACS, março de 2020 a fevereiro de 2023. Os descritores foram utilizados de forma combinada: "Covid-19", "Transplante de órgãos (Organ transplant)" e "Impacto (Impact)". Resultados: Foram encontrados 24 artigos. Diante da emergência da situação provocada pela síndrome respiratória aguda causada pela Covid-19, houve ocupação de unidades de terapia intensiva (UTI), gerando indisponibilidade de leitos para pacientes transplantados. O número de transplantes sofreu decréscimo diante dos impactos da pandemia de Covid-19. Conclusões: A pandemia de Covid-19 impactou os receptores de órgãos na diminuição de transplantes e doação de órgãos, repercutindo nos aspectos emocionais e psicológicos dos pacientes e de suas famílias, bem como dos profissionais de saúde, cujo desafio é garantir a continuidade dos procedimentos. Nota-se a importância da promoção de políticas públicas que favoreçam a melhor organização e disponibilidade de leitos para a realização de transplantes.

Introduction: This article presents an literary review of the organ transplant impact in the Covid-19 pandemic scenario. Organ transplant programs all over the world faced serious challenges during this period, affecting the tissue and organ availability, safety of the receptors, donors and the medical resources. Objective: Perform a withdrawal of the aspects related to the impacts of Covid-19 pandemic in the context of tissue and organ procurement. Method: Was made a systematic review with research in the databases of PubMed, SciELO and LILACS, from March 2020 to February 2023. The descriptors used in a combined manner were: Covid-19, organ transplant and impact. Results: 24 articles were found. Facing the acute respiratory syndrome emergency caused by the Covid-19, intensive care units (ICU) were occupied, resulting in a unavailability of beds to the transplant patients. The number of transplants suffered a decrease in front of Covid-19 pandemic. Conclusion: The Covid-19 pandemic impacted the organ receptors according to the transplantation and organ donation decrease, reflecting in emotional and psychological aspects of patients and their family, as well as healthcare professionals, whose challenge is to ensure the continuity of procedures. It is noticed the importance in promoting public policies that favor better organization and availability of beds for transplantation

The effects of tradition on problem solving by two wild populations of bearded capuchin monkeys in a probing task.

The effects of culture on individual cognition have become a core issue among cultural primatologists. Field studies with wild populations provide evidence on the role of social cues in the ontogeny of tool use in non-human primates, and on the transmission of such behaviours over generations through socially biased learning. Recent experimental studies have shown that cultural knowledge may influence problem solving in wild populations of chimpanzees. Here, we present the results from a field experiment comparing the performance of bearded capuchin monkeys (Sapajus libidinosus) from two wild savannah populations with distinct toolkits in a probing task. Only the population that already exhibited the customary use of probing tools succeeded in solving the new problem, suggesting that their cultural repertoire shaped their approach to the new task. Moreover, only this population, which uses stone tools in a broader range of contexts, tried to use them to solve the problem. Social interactions can affect the formation of learning sets and they affect the performance of the monkeys in problem solving. We suggest that behavioural traditions affect the ways non-human primates solve novel foraging problems using tools.

Diversity of nutcracking tool sites used by Sapajus libidinosus in Brazilian Cerrado.

Cracking nuts with tools is a behavior documented in a small number of populations of tufted capuchins, mainly in semi-arid Caatinga and Caatinga-Cerrado transitional environments of northeastern Brazil. Only one of these populations inhabits the less arid Cerrado in Central Brazil, where environments are composed of a heterogeneous mosaic of fields, savannas and forest formations. We conducted surveys in 10 of 20 localities where nutcracking by capuchins was reported by the local inhabitants in the Cerrrado of Northern Goiás and Tocantins. Our purpose was to evaluate nutcracking sites (anvils and associated hammers and nuts) based on indirect evidence of extensive pounding of nuts and seeds. Nutcracking was confirmed at all 10 surveyed localities. A total of 270 sites were identified. Surveyed localities included areas that were ecologically similar to those where capuchins crack nuts in Caatinga, as well as less arid localities with more typical Cerrado habitat. Anvils and hammers were made of materials including quartz, limestone, sandstone and wood, and displayed a wider range of sizes (i.e., 60-3,750 g for hammers' weight) than reported at previously studied localities. Nuts of seven genera were found in association with anvils and hammers. We conclude that nutcracking by capuchins are not restricted to arid environments and argue that the occurrence and diversity of nutcracking tool sites result from complex interactions of environmental variables (e.g., availability of food and mineral resources, density of canopy cover) and social variables (e.g., spatial cohesiveness and tolerance among group members) that need to be examined through long-term research of habituated groups. Localities in the Cerrado of Northern Goiás and Tocantins vary considerable in the ecological conditions faced by wild groups, and therefore offer the opportunity to examine these interactions.

Stone anvil damage by wild bearded capuchins (Sapajus libidinosus) during pounding tool use: a field experiment.

We recorded the damage that wild bearded capuchin monkeys (Sapajus libidinosus) caused to a sandstone anvil during pounding stone tool use, in an experimental setting. The anvil was undamaged when set up at the Fazenda Boa Vista (FBV) field laboratory in Piauí, Brazil, and subsequently the monkeys indirectly created a series of pits and destroyed the anvil surface by cracking palm nuts on it. We measured the size and rate of pit formation, and recorded when adult and immature monkeys removed loose material from the anvil surface. We found that new pits were formed with approximately every 10 nuts cracked, (corresponding to an average of 38 strikes with a stone tool), and that adult males were the primary initiators of new pit positions on the anvil. Whole nuts were preferentially placed within pits for cracking, and partially-broken nuts outside the established pits. Visible anvil damage was rapid, occurring within a day of the anvil's introduction to the field laboratory. Destruction of the anvil through use has continued for three years since the experiment, resulting in both a pitted surface and a surrounding archaeological debris field that replicate features seen at natural FBV anvils.

Resolução de problema por macacos-prego selvagens (Sapajus libidinosus) de duas populações com diferentes repertórios de uso de ferramentas / Problem solving by wild bearded capuchin monkeys (Sapajus libidinosus) from two populations with different tool-use repertoires

Os macacos-prego (Sapajus libidinosus) são reconhecidos pela flexibilidade comportamental, incluindo o uso de ferramentas na natureza. Admite-se que o contexto social contribua para aprendizagem individual de comportamentos flexíveis pelos macacos-prego. A influência social sobre a aprendizagem é considerada como uma característica básica da cultura. As diferenças observadas no conjunto de ferramentas entre populações naturais de macacos-prego sugerem a existência de tradições nestes primatas. Em um experimento em campo apresentamos aos macacos de duas populações, que diferiam acerca de suas tradições instrumentais, um problema que exigia o uso de sondas para obter melaço dentro de uma caixa-problema. Investigamos se os macacos destas populações abordariam o problema de acordo com as respectivas tradições instrumentais. As populações investigadas habitam diferentes regiões do Estado do Piauí, interior do nordeste brasileiro, e distam aproximadamente 350Km entre si, sendo a paisagem ecológica tipicamente marcada pelo bioma cerrado/caatinga. Os macacos da população da Fazenda Boa Vista (FBV) são proficientes no uso de percutores durante o processamento de cocos-de-palmeiras e frutos secos de caju. Apesar de quase uma década de observação sistemática nesta população, não foi observado o uso de outras ferramentas por estes macacos. Os macacos da população do Parque Nacional da Serra da Capivara (PNSC), por sua vez, utilizam habitualmente um conjunto diversificado de ferramentas, incluindo o uso de percutores e sondas. Nossa hipótese predisse que os macacos da população PNSC (grupo Pedra Furada) resolveriam o problema em menor tempo e apresentariam melhor desempenho, enquanto os macacos da FBV (grupo Chicão) não utilizariam sondas durante as tentativas de obter o melaço, ou demandariam maior tempo até alcançarem o sucesso no problema, e esperávamos pudessem percutir pedras contra a caixa.(AU)

Capuchin monkeys (Sapajus libidinosus) have been recognized by their behavioral flexibility, including tool-using in nature. Currently, its acknowledged that social context contributes to individual learning of that flexible behavior by capuchin monkeys. The social influence on learning is the most basic feature of culture. The differences observed in tool kit exhibited in natural populations of capuchin monkeys suggest the existence of culture in these New World primates. We ran a field experiment in two populations of capuchin monkeys which differed in their tool use traditions. In this experiment we presented a problem that required probe-tool using to reach molasses available inside the problem-box. We investigated whether monkeys from these populations approached the problem according to their respectively tool use traditions. Both populations inhabit different regions in the State of Piauí, in Northeastern Brazil, and are about 350Km apart. The ecological landscapes of these research sites are the the savana-like cerrado and caatinga biomes. Monkeys from Fazenda Boa Vista (FBV) are proficient pounding-tool users that habitually use stones as hammers to crack open palm-nuts and dry cashew fruit. After almost a decade of systematic observations, no other form of tool use was observed in this population. Capuchin monkeys from Parque Nacional da Serra da Capivara (PNSC), on the other hand, have been observed using a much broader tool-kit, including pounding tools, as well as probing tools during their foraging activities. Our hypothesis predicted that capuchins from the PNSC population (Pedra Furada group) would take less time to solve the task than capuchins from FBV (Chicão group), and also that they would perform better in comparison to that group. We also expected that Chicão group would pound stones against the problem box.(AU)