EFEITOS DA EXIGÊNCIA DE DESEMPENHOS ENTRELAÇADOS SOBRE LINHA DE BASE EM ESQUEMA SIMPLES DE REFORÇO

This study investigated the effects of an interlocking performance requirement, spacing of responses of three participants, on the triads’ operant pattern in variable interval schedule of reinforcement. The task consisted of a kind of game in which the only possible response, click the mouse button, was free to occur and could produce individual consequences (in VI 3 s or VI 12 s) and consequences contingent on the requirement that participants to click spaced with respect to each other. Twelve college students constituted four triads. Two conditions were programmed in a reversal design ABAB: Condition A, only operant contingency was in effect; Condition B, operant and cultural contingencies in effect. The results showed that, regardless of the individual schedule of reinforcement parameters, the overlap of an interlocking performance requirement selected a pattern of coordination among participants' responses. The suspension and reintroduction of interlocking requirement showed that systematic changes in the pattern of occurrence of interlocking behavior were function of the manipulated variable. The requirement of spacing between participants' responses to produce an experimentally arranged consequence can be characterized as a metacontingency. The procedure, in this sense, demonstrates the effects of different levels of variation and selection in action simultaneously for individual behavior and for interlocking performances. Key words: Cultural Selection, interlocking behavioral contingencies, schedules of reinforcement, free operant. Foram investigados os efeitos da exigência de desempenhos entrelaçados, espaçamento de respostas de três participantes, sobre o responder de tríades em esquemas de reforço em intervalo variável. A tarefa consistiu em um jogo, no qual a única resposta possível, clicar o botão do mouse, era livre para ocorrer e podia produzir consequências individuais (em VI 3 s ou VI 12 s) e consequências contingentes à exigência de que os participantes clicassem espaçadamente em relação uns aos outros. Doze estudantes universitários formaram quatro tríades. Duas condições foram programadas em um delineamento de reversão ABAB: Condição A, apenas contingência operante; Condição B, contingências operante e cultural em vigor. Os resultados mostraram que, independente do parâmetro do esquema de reforçamento individual, a sobreposição da exigência de desempenho entrelaçado selecionou um padrão de coordenação entre as respostas dos participantes. A suspensão e reintrodução da exigência do entrelaçamento mostrou que mudanças sistemáticas no padrão de ocorrência dos desempenhos entrelaçados foram função da variável manipulada. A exigência de espaçamento entre as respostas dos participantes para produção de uma consequência arranjada experimentalmente pode ser caracterizada como uma metacontingência. O procedimento, nesse sentido, demonstra a atuação de níveis diferentes de variação e seleção em ação simultaneamente para o comportamento dos participantes e para desempenhos entrelaçados. Palavras-chave: Seleção cultural, contingências comportamentais entrelaçadas, esquemas de reforço, operante livre.

Gender Differences in COVID-19 Among Liver Transplant Recipients: Results from a Multicenter Brazilian Cohort

Introduction: Existing literature presents varying perspectives on the impact of COVID-19 on liver transplant recipients.However, no research has specifically investigated the role of gender differences in the manifestation of COVID-19 among liver transplant recipients. This study aims to examine the effects of COVID-19 on liver transplant recipients, with a focus on gender differences in disease presentation and progression. Methods: Conducted as a multicenter historical cohort study, this research collected patient records through an online questionnaire. Assessing COVID-related mortality was the main objective. Additionally, demographic, clinical, and laboratory data pertaining to disease presentation and progression werecollected. Results: The study included a total of 283 patients, of whom 76 were female and 206 were male. The median follow-up period for males was 99 days (IQR 38-283), while for females, it was 126 days (IQR 44-291). A higher prevalence of cardiovascular disease was observed in males (p=0.002). Females frequently experienced a loss of smell (p=0.021), whereas males commonly exhibited fever (p=0.031). Levels of ALT and gamma-glutamyl transferase were significantly elevated in males (p=0.008 and 0.004, respectively). Although there was a trend towards increased mortality in males, it did not reach statistical significance. Conclusion: This study is the first attempt to investigate gender differences in COVID-19 among liver transplant recipients. Our findings highlight the need for a comprehensive and personalised approach to treating this patient population and underscore the importance of further elucidating the disease presentation in these individuals

Behavior and illusions: a model to study superstition in a participant replacement experiment

Abstract The notion of superstitious behavior can provide a basic background for understanding such notions as illusions and beliefs. The present study investigated the social mechanism of the transmission of superstitious behavior in an experiment that utilized participant replacement. The sample was composed of a total of 38 participants. Participants performed a task on a computer: they could click a colored rectangle using the mouse. When the rectangle was in a particular color, the participants received points independently of their behavior (variable time schedule). When the color of the rectangle was changed, no points were presented (extinction). Under an Individual Exposure condition, ten participants worked alone on the task. Other participants were exposed to the same experimental task under a Social Exposure condition, in which each participant first learned by observation and then worked on the task in a participant replacement (chain) procedure. The first participant in each chain in the Social Exposure condition was a confederate who worked on the task “superstitiously,” clicking the rectangle when points were presented. Superstitious responding was transmitted because of the behavior of the confederate. This also influenced estimates of personal control. These findings suggest that social learning can facilitate the acquisition and maintenance of superstitious behavior and the illusion of control. Our data also suggest that superstitious behavior and the illusion of control may involve similar learning principles

Comparative Analysis of Muscle Hypertrophy Models Reveals Divergent Gene Transcription Profiles and Points to Translational Regulation of Muscle Growth through Increased mTOR Signaling

Skeletal muscle mass is a result of the balance between protein breakdown and protein synthesis. It has been shown that multiple conditions of muscle atrophy are characterized by the common regulation of a specific set of genes, termed atrogenes. It is not known whether various models of muscle hypertrophy are similarly regulated by a common transcriptional program. Here, we characterized gene expression changes in three different conditions of muscle growth, examining each condition during acute and chronic phases. Specifically, we compared the transcriptome of Extensor Digitorum Longus (EDL) muscles collected (1) during the rapid phase of postnatal growth at 2 and 4 weeks of age, (2) 24 h or 3 weeks after constitutive activation of AKT, and (3) 24 h or 3 weeks after overload hypertrophy caused by tenotomy of the Tibialis Anterior muscle. We observed an important overlap between significantly regulated genes when comparing each single condition at the two different timepoints. Furthermore, examining the transcriptional changes occurring 24 h after a hypertrophic stimulus, we identify an important role for genes linked to a stress response, despite the absence of muscle damage in the AKT model. However, when we compared all different growth conditions, we did not find a common transcriptional fingerprint. On the other hand, all conditions showed a marked increase in mTORC1 signaling and increased ribosome biogenesis, suggesting that muscle growth is characterized more by translational, than transcriptional regulation

Comparative Analysis of Muscle Hypertrophy Models Reveals Divergent Gene Transcription Profiles and Points to Translational Regulation of Muscle Growth through Increased mTOR Signaling

Skeletal muscle mass is a result of the balance between protein breakdown and protein synthesis. It has been shown that multiple conditions of muscle atrophy are characterized by the common regulation of a specific set of genes, termed atrogenes. It is not known whether various models of muscle hypertrophy are similarly regulated by a common transcriptional program. Here, we characterized gene expression changes in three different conditions of muscle growth, examining each condition during acute and chronic phases. Specifically, we compared the transcriptome of Extensor Digitorum Longus (EDL) muscles collected (1) during the rapid phase of postnatal growth at 2 and 4 weeks of age, (2) 24 h or 3 weeks after constitutive activation of AKT, and (3) 24 h or 3 weeks after overload hypertrophy caused by tenotomy of the Tibialis Anterior muscle. We observed an important overlap between significantly regulated genes when comparing each single condition at the two different timepoints. Furthermore, examining the transcriptional changes occurring 24 h after a hypertrophic stimulus, we identify an important role for genes linked to a stress response, despite the absence of muscle damage in the AKT model. However, when we compared all different growth conditions, we did not find a common transcriptional fingerprint. On the other hand, all conditions showed a marked increase in mTORC1 signaling and increased ribosome biogenesis, suggesting that muscle growth is characterized more by translational, than transcriptional regulation

Impact of reproductive and productive rates on levels of inbreeding and genetic gain of pigs through data simulation

The objective of this study was to evaluate the impact of farrowing and mortality rates on inbreeding levels and genetic gain through data simulation. Data came from two real populations A and B, composed of Pietrain and Landrace breed pigs, respectively. To generate the simulated populations, a Fortran-language simulator was developed using the (co)variances of the breeding values and productive and reproductive information obtained from populations A and B, as well as restrictions on mating and animals selected per generation. Two data files were created. The first contained the pedigree of the previous 10 years, with 21,906 and 251,343 animals in populations A and B, respectively. The second included the breeding values for age, backfat thickness, and feed conversion, all of which were adjusted for 110 kg live weight, for both populations; longissimus dorsi muscle depth adjusted for 110 kg live weight, for population A only; and number of live piglets at the fifth day of life per farrowing, for population B only. Three scenarios were simulated by varying the farrowing and mortality rates during the lactation period. Ten generations were simulated, with 30 replicates for each generation and scenario. Inbreeding levels in closed production units increase with productive and reproductive losses, and these reduce the variances of breeding values, selection intensity, and genetic gains by reducing the number of animals available for selection. Actions that maximize farrowing rates are more important than those that minimize mortality rates during the lactation period, since a reduction in simulated farrowing resulted in greater losses of genetic gain

Insulin/IGF1 signalling mediates the effects of β2‐adrenergic agonist on muscle proteostasis and growth

Abstract Background Stimulation of β2‐adrenoceptors can promote muscle hypertrophy and fibre type shift, and it can counteract atrophy and weakness. The underlying mechanisms remain elusive. Methods Fed wild type (WT), 2‐day fasted WT, muscle‐specific insulin (INS) receptor (IR) knockout (M‐IR−/−), and MKR mice were studied with regard to acute effects of the β2‐agonist formoterol (FOR) on protein metabolism and signalling events. MKR mice express a dominant negative IGF1 receptor, which blocks both INS/IGF1 signalling. All received one injection of FOR (300 μg kg−1 subcutaneously) or saline. Skeletal muscles and serum samples were analysed from 30 to 240 min. For the study of chronic effects of FOR on muscle plasticity and function as well as intracellular signalling pathways, fed WT and MKR mice were treated with formoterol (300 μg kg−1 day−1) for 30 days. Results In fed and fasted mice, one injection of FOR inhibited autophagosome formation (LC3‐II content, 65%, P ≤ 0.05) that was paralleled by an increase in serum INS levels (4‐fold to 25‐fold, P ≤ 0.05) and the phosphorylation of Akt (4.4‐fold to 6.5‐fold, P ≤ 0.05) and ERK1/2 (50% to two‐fold, P ≤ 0.05). This led to the suppression (40–70%, P ≤ 0.05) of the master regulators of atrophy, FoxOs, and the mRNA levels of their target genes. FOR enhanced (41%, P ≤ 0.05) protein synthesis only in fed condition and stimulated (4.4‐fold to 35‐fold, P ≤ 0.05) the prosynthetic Akt/mTOR/p70S6K pathway in both fed and fasted states. FOR effects on Akt signalling during fasting were blunted in both M‐IR−/− and MKR mice. Inhibition of proteolysis markers by FOR was prevented only in MKR mice. Blockade of PI3K/Akt axis and mTORC1, but not ERK1/2, in fasted mice also suppressed the acute FOR effects on proteolysis and autophagy. Chronic stimulation of β2‐adrenoceptors in fed WT mice increased body (11%, P ≤ 0.05) and muscle (15%, P ≤ 0.05) growth and downregulated atrophy‐related genes (30–40%, P ≤ 0.05), but these effects were abolished in MKR mice. Increases in muscle force caused by FOR (WT, 24%, P ≤ 0.05) were only partially impaired in MKR mice (12%, P ≤ 0.05), and FOR‐induced slow‐to‐fast fibre type shift was not blocked at all in these animals. In MKR mice, FOR also restored the lower levels of muscle SDH activity to basal WT values and caused a marked reduction (57%, P ≤ 0.05) in the number of centrally nucleated fibers. Conclusions NS/IGF1 signalling is necessary for the anti‐proteolytic and hypertrophic effects of in vivo β2‐adrenergic stimulation and appears to mediate FOR‐induced enhancement of protein synthesis. INS/IGF1 signalling only partially contributes to gain in strength and does not mediate fibre type transition induced by FOR

Avaliação protéica de uma nova multimistura com base no milho QPM BR 473 Protein evaluation of a nutritional supplement based on QPM BR 473 maize

A multimistura tem sido utilizada no Brasil pela Pastoral da Criança, em parceria com governos municipais, a fim de reduzir a desnutrição infantil. Não obstante, a eficácia deste suplemento tem sido constantemente arguida, devido à possível presença de fatores antinutricionais. No presente trabalho descrevemos a avaliação biológica de um suplemento contendo milho QPM BR473. Trinta e seis ratos Wistar machos, com 21-23 dias de idade, foram divididos em seis grupos de seis animais cada e alimentados com dietas de caseína contendo multimistura pura, com QPM BR473, láctea (contendo leite em pó), láctea contendo QPM BR473 ou a multimistura proposta (contendo QPM BR473, farinhas de aveia, soja e banana e açúcar mascavo). Mediu-se a Retenção Protéica Líquida. A condição microbiológica dos suplementos e seu custo foram também determinados. Os resultados obtidos mostraram que o QPM BR473 pode ser usado em suplementos nutricionais, com alto valor nutritivo, expresso por sua qualidade protéica, e com baixa relação custo/benefício.<br>Nutritional supplements, known as "multimisturas", prepared with low cost ingredients have been distributed in Brazil by municipal governments, in partnership with non-governmental organizations, in order to reduce infant malnutrition. Nevertheless the efficacy of these supplements has been constantly argued, due to the possible presence of anti-nutritional factors. The present work describes the biological evaluation of a supplement containing Quality Protein Maize BR 473. Thirty six 21-23-day old male Wistar rats were divided into six groups of six animals each. The groups were fed casein diets, each containing respectively: "multimistura", "multimistura" with QPM BR 473, "multimistura" with powdered milk, "multimistura" with powderedmilk and QPM BR 473 or the proposed new supplement (containing QPM BR 473 flour, oat meal, soybean flour, brown sugar and banana meal). Net protein retention was measured. Microbiological condition and cost of the supplements were also determined. The results showed that QPM BR 473 can be used in nutritional supplements, with high nutritional value, as expressed by its protein quality, and low cost/benefit ratio