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Introduction: The COVID-19 pandemic, with over 83 million confirmed cases and 1.8 million deaths, has raised concerns about long-term cognitive issues, especially in populations facing disparities. Despite a few years since Peru's first COVID-19 wave, the cognitive effects on adults remain unclear. This study is the first in Peru to explore COVID-19's impact on general cognition and executive function. Methods: A retrospective cross-sectional study compared individuals with COVID-19 history to controls, assessing general cognition, verbal fluency, attention, and executive function. Among 240 assessed, 154 met the study inclusion criteria, with about 60% female and an average age of 38.89 ± 16.001 years. Groups included controls (n = 42), acute phase (AP, n = 74) (1-14 days of symptoms), and hyperinflammatory phase (HP, n = 38) (>14 days of symptoms). Results: Significant cognitive differences were observed. The HP group exhibited lower general cognitive performance (p = 0.02), working memory (p = 0.01), and executive function (planning; p < 0.001; flexibility; p = 0.03) than controls. Those with <14 days of illness (AP vs. HP) had deficits in general cognitive performance (p = 0.02), working memory (p = 0.02), and planning (p < 0.001), mainly during the hyperinflammatory phase, showing differences in working memory (p = 0.003) and planning (p = 0.01). Gender differences emerged, with males in the HP phase having poorer working memory (p = 0.003) and planning (p = 0.01). Discussion: This study underscores COVID-19's negative impact on cognitive function, even in mild cases, with potential heightened effects in men during acute or hyperinflammatory phases. The findings provide Peru's first evidence, highlighting the vulnerability of populations facing socioeconomic disparities.

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Breast cancer is one of the leading causes of death that affects the female population worldwide. Despite advances in treatments and a greater understanding of the disease, there are still difficulties in successfully treating patients. Currently, the main challenge in the field of cancer vaccines is antigenic variability which can reduce antigen-specific T- cell response efficacy. The search for and validation of immunogenic antigen targets increased dramatically over the past few decades and, with the advent of modern sequencing techniques, permitting the fast and accurate identification of the neoantigen landscape of tumor cells, will undoubtedly continue to grow exponentially for years to come. We have previously implemented Variable Epitope Libraries (VEL) as an unconventional vaccine strategy in preclinical models and for identifying and selecting mutant epitope variants. Here, we used an alanine-based sequence to generate a 9-mer VEL-like combinatorial mimotope library G3d as a new class of vaccine immunogen. An in silico analysis of the 16,000 G3d-derived sequences revealed potential MHC-I binders and immunogenic mimotopes. We demonstrated the antitumor effect of treatment with G3d in the 4T1 murine model of breast cancer. Moreover, two different T cell proliferation screening assays against a panel of randomly selected G3d-derived mimotopes allowed the isolation of both stimulatory and inhibitory mimotopes showing differential therapeutic vaccine efficacy. Thus, the mimotope library is a promising vaccine immunogen and a reliable source for isolating molecular cancer vaccine components.

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RESUMEN Fundamento La infección por virus de inmunodeficiencia humana/sida continúa siendo un problema de salud a pesar de la reducción de sus tasas de incidencia. Objetivo describir el comportamiento del virus de inmunodeficiencia humana/sida en la provincia Cienfuegos en el período 2014-2019. Métodos se realizó un estudio descriptivo, con un universo de 556 pacientes diagnosticados con el Virus de Inmunodeficiencia Humana. Se utilizaron las series cronológicas de casos y se analizaron las variables incidencia, prevalencia, edad, sexo, accesibilidad al tratamiento antirretroviral y transmisión materno infantil. Se calcularon, además, tasas y por cientos. Resultados predominaron los pacientes de 25 a 49 años de edad, quienes representaron un 67 %. Se observó tendencia al descenso en las tasas de incidencia de la enfermedad en la provincia. Al concluir 2019, el 98,2% de los pacientes se encontraba bajo tratamiento antirretroviral. No se reportó transmisión materno infantil en el período de estudio. Conclusión El estudio realizado evidenció las características de la epidemia de virus de inmunodeficiencia humana/sida en la provincia de Cienfuegos durante el periodo de estudio, la cual mostró tendencia a la reducción de sus tasas de incidencia, así como el acceso garantizado al tratamiento antirretroviral, que, unido a los protocolos de atención, ha permitido eliminar la transmisión materno infantil.

ABSTRACT Background Human immunodeficiency virus infection/AIDS continues to be a health problem despite the reduction in its incidence rates. Objective to describe the behavior of the human immunodeficiency virus/AIDS in the Cienfuegos province from 2014 to 2019. Methods a descriptive study was carried out, 556 patients were studied and diagnosed with the Human Immunodeficiency Virus. Chronological series of cases were used and the variables incidence, prevalence, age, sex, accessibility to antiretroviral treatment and mother-to-child transmission were analyzed. Rates and percentages were also calculated. Results patients from 25 to 49 years of age predominated, who represented 67%. A downward trend was observed in the incidence rates of the disease in the province. At the end of 2019, 98.2% of patients were under antiretroviral treatment. No mother-to-child transmission was reported in the study period. Conclusion The study carried out evidenced the characteristics of the human immunodeficiency virus/AIDS epidemic in the Cienfuegos province during the study period, which showed a tendency to reduce its incidence rates, as well as guaranteed access to antiretroviral treatment, which, together with care protocols, has made it possible to eliminate mother-to-child transmission.

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RESUMEN Fundamento El comportamiento endemo-epidémico del dengue en Cienfuegos ha mostrado una incidencia creciente cada año en la población infantil, con incremento en el reporte de signos de alarma. El correcto abordaje hospitalario de estos casos, con vistas a evitar desenlaces fatales, reviste gran importancia para el área materno-infantil. Objetivo caracterizar a los pacientes con sospecha clínica de dengue y que desarrollaron signos de alarma. Métodos se realizó un estudio descriptivo, que incluyó a 41 pacientes ingresados en Unidad de Cuidados Intensivos del Hospital Pediátrico de Cienfuegos en el año 2019. Las variables analizadas fueron: sexo, edad, estado nutricional y enfermedades crónicas asociadas, tiempo entre el ingreso y comienzo de los síntomas, signos de alarma de la enfermedad, reflejo en la historia clínica de situación epidemiológica del entorno de la vivienda y/o centro de estudio, estadía hospitalaria y evolución clínica. Resultados predominó el sexo femenino y las edades preescolares, así como los normopeso (95,1 %). El 26,8 % padecía enfermedades crónicas. Predominaron los pacientes ingresados pasadas más de 48 horas del comienzo de los síntomas. Los signos de alarma más frecuentes fueron la trombocitopenia, líquido en cavidad (pleural, pericárdico y perivesicular), vómitos y dolor abdominal. La evolución fue favorable. Conclusión Los signos de alarma identificados denotan que los pacientes de la serie pudieron haber evolucionado hacia la etapa grave de la enfermedad, sin embargo, gracias a la detección precoz de los signos y a la atención recibida, la evolución fue favorable.

ABSTRACT Background The endemic-epidemic behavior of dengue in Cienfuegos has shown an increasing incidence every year in the child population, with an increase in the report of warning signs. The correct hospital approach to these cases, to avoiding fatal outcomes, is of great importance for the maternal and child area. Objective to characterize patients with clinical suspicion of dengue and who developed warning signs. Methods a descriptive study was carried out, which included 41 patients admitted to the Intensive Care Unit of the Cienfuegos Pediatric Hospital in 2019. The variables analyzed were: sex, age, nutritional status and associated chronic diseases, time between admission and beginning of symptoms, warning signs of the disease, reflection in the clinical history of the home and / or study center environment epidemiological situation, hospital stay and clinical evolution. Results female sex and preschool ages predominated, as well as normal weight (95.1%). 26.8% suffered from chronic diseases. Patients admitted more than 48 hours after the beginning of symptoms predominated. The most frequent warning signs were thrombocytopenia, fluid in the cavity (pleural, pericardial and perivesicular), vomiting and abdominal pain. The evolution was favorable. Conclusion The identified alarm signs indicate that the patients in the series could have evolved towards the severe stage of the disease, however, thanks to the early detection of the signs and the care received, the evolution was favorable.

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Introducción: El cáncer de mama es la neoplasia más común a nivel mundial en mujeres, y en el Perú es la segunda causa de muerte por cáncer. Objetivo: Determinar los factores sociodemográficos asociados a la toma de mamografía en mujeres peruanas durante el año 2015. Métodos: Estudio transversal. Se seleccionaron los datos de mujeres de 40 a 49 años, provenientes de la Encuesta Demográfica y de Salud Familiar (ENDES), 2015. Los factores sociodemográficos estudiados incluyeron al nivel educativo, estado marital, nivel educativo y edad de la pareja, edad al momento del matrimonio, índice de riqueza, lugar de residencia y región natural de residencia. Resultados: Se incluyeron 2183 mujeres, el 57,6% refirió tener secundaria completa, 64% tuvo pareja, 24,8% fue muy pobre, y 72,1% vivía en área rural. Los factores asociados a la toma de una mamografía fueron tener pareja con estudios superiores, edad al matrimonio de 25 años a más, y residencia urbana (costa y Lima Metropolitana). Conclusiones: Según la ENDES 2015, sólo el 16,9% de mujeres peruanas de entre 40 y 49 años se realizó una mamografía, existiendo factores sociodemográficos asociados a la realización de la misma.

Introduction: Breast cancer is the most common type of cancer in women. In Peru, it is the second leading cause of death by cancer. Objective: To determine the sociodemographic factors associated with taking mammography in Peruvian women. Methods: A cross-sectional study. Data of women (40-49 years-old) were selected from Demographic and Family Health Survey databases in 2015. Studied factors included educational level, civil status, educational level and age from partners, marriage age, wealth index, place of residence, and natural region. Results: 2183 women were included, 57,6% reported having full secondary school, 64% had a partner, 24,8% were very poor, and 72,1% lived in rural areas. The factors associated with taking a mammogram were having a partner with higher education, marriage age of 25 years and older, and urban residence (coast and Metropolitan Lima). Conclusions: According ENDES 2015, only 16.9% of Peruvian women between the ages of 40 and 49 have had a mammography, with associated sociodemographic factors.

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Ecological communities are structured by multiple processes operating at multiple scales yet understanding the scale-dependency of these processes remains an open challenge. This might be particularly true for parasites, for which biotic rather than abiotic processes may play a primary role in structuring communities. Focusing on vines, a group of structural parasites that gain access to the canopy using different climbing mechanisms, we examined the influence of abiotic factors in tandem with host-parasite and parasite-parasite interactions in the assembly of tropical vine communities. Two synthetic variables, namely Climate1 and landscape Variety, were consistently important in explaining variation in species richness and diversity, as well as species composition, but their importance varied with scale. Whereas Climate1 summarizes the largest variability among climatic variables, landscape Variety expresses landscape heterogeneity within a neighborhood. Significant patterns of species co-occurrences suggest that vine-vine interactions also contribute to vine community assembly. Our results may be critical to understand vine proliferation and help design management strategies for their control.

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BACKGROUND: Potato frying color is an agronomic trait influenced by the sugar content of tubers. The candidate gene approach was employed to elucidate the molecular basis of this trait in Solanum tuberosum Group Phureja, which is mainly diploid and represents an important genetic resource for potato breeding. The objective of this research was to identify novel genetic variants related with frying quality in loci with key functions in carbohydrate metabolism, with the purpose of discovering genetic variability useful in breeding programs. Therefore, an association analysis was implemented with 109 SNP markers identified in ten candidate genes. RESULTS: The analyses revealed four associations in the locus InvGE coding for an apoplastic invertase and one association in the locus SssI coding for a soluble starch synthase. The SNPs SssI-C 45711901 T and InvGE-C 2475454 T were associated with sucrose content and frying color, respectively, and were not found previously in tetraploid genotypes. The rare haplotype InvGE-A 2475187 C 2475295 A 2475344 was associated with higher fructose contents. Our study allowed a more detailed analysis of the sequence variation of exon 3 from InvGE, which was not possible in previous studies because of the high frequency of insertion-deletion polymorphisms in tetraploid potatoes. CONCLUSION: The association mapping strategy using a candidate gene approach in Group Phureja allowed the identification of novel SNP markers in InvGE and SssI associated with frying color and the tuber sugar content measured by High Performance Liquid Chromatography (HPLC). These novel associations might be useful in potato breeding programs for improving quality traits and to increase crop genetic variability. The results suggest that some genes involved in the natural variation of tuber sugar content and frying color are conserved in both Phureja and tetraploid germplasm. Nevertheless, the associated variants in both types of germplasm were present in different regions of these genes. This study contributes to the understanding of the genetic architecture of tuber sugar contents and frying color at harvest in Group Phureja.

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This work performed a phenotypic and genotypic characterization of 79 clinical isolates of Enterobacteriaceae and Pseudomonadaceae collected in hospitals of Southern Ecuadorin 2013. Our results showed a high incidence of ß-lactamases and ESBLs with blaTEM and blaCTX-M as the prevalent genes, respectively. By direct sequencing of PCR amplicons, the different ß-lactamases and variants of the genes were also distinguished. Our results revealed a predominance of TEM-1 ß-lactamase and the presence of different CTX-M variants with a prevalence of CTX-M-15. Two infrequent CTX-M variants in South America were also identified. To the best of our knowledge, this is one of the first studies describing the genetic characteristics of ß-lactamases in Ecuador.

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BACKGROUND: Potato frying quality is a complex trait influenced by sugar content in tubers. Good frying quality requires low content of reducing sugars to avoid the formation of dark pigments. Solanum tuberosum Group Phureja is a valuable genetic resource for breeding and for genetic studies. The sugar content after harvest was analyzed in a germplasm collection of Group Phureja to contribute to the understanding of the natural variation of this trait. RESULTS: Sucrose, glucose and fructose genotypic mean values ranged from 6.39 to 29.48 g kg(-1) tuber dry weight (DW), from 0.46 to 28.04 g kg(-1) tuber DW and from 0.29 to 27.23 g kg(-1) tuber DW, respectively. Glucose/fructose and sucrose/reducing sugars ratios ranged from 1.01 to 6.67 mol mol(-1) and from 0.15 to 7.78 mol mol(-1) , respectively. Five clusters of genotypes were recognized, three of them with few genotypes and extreme phenotypic values. CONCLUSION: Sugar content showed a wide variation, representing the available variability useful for potato breeding. The results provide a quantitative approach to analyze the frying quality trait and are consistent with frying color. The analyzed germplasm presents extreme phenotypes, which will contribute to the understanding of the genetic basis of this trait. © 2016 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

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Cayo Santiago is the oldest continuously operating free-ranging rhesus monkey colony in the world. Population control of this colony has historically been carried out by periodic live capture and removal of animals. However, the effect of such a strategy on the size, growth rate, age structure, and sex ratio of the population has not been analyzed. This study reviews past removal data and uses a population projection model to simulate the effects of different removal schemes based on Cayo Santiago demographic data from 2000-2012. The model incorporates negative density-dependence in female fertility, as well as male and female survival rates, to determine the population-level effects of selective removal by age and sex. Modeling revealed that removal of sexually immature individuals has negligible effects on the population dynamics explaining why with an initial population of 1309 in 2000 and annual removals of immature monkeys a mean annual population growth rate of 12% and a final population size of ∼1,435 individuals by 2012 (∼0.009 animal/m(2) ) was observed. With no removals, the population is expected to exhibit dampened oscillations until reaching equilibrium at ∼1,690 individuals (∼0.0111 animal/m(2) ) in 2,100. In contrast, removal of adult females (≥4 yrs) would significantly reduce the population size, but would also promote an increase in population growth rate due to density feedback. A maximum annual production of 275 births is expected when 550 adult females are present in the population. Sensitivity analyses showed that removing females, in contrast to controlling their fertility through invasive treatments would contribute the most to changes in population growth rate. Given the density compensation on fertility, stabilizing the population would require removing ∼80% of the current population of adult females. This study highlights the importance of addressing the population-level density effects, as well as sensitivity analyses, to optimize management strategies.

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Reproductive synchrony and the consequent clustering of births are hypothesized to be regulated by seasonal changes in rainfall and food availability. Such climate-related seasonality is, however, questionable in tropical populations occupying temporally invariant habitats year round. Using the long-term data of the Cayo Santiago rhesus macaques from 1973 to 2013, this study distinguishes synchrony (a greater than chance clustering of births) from seasonality (a cluster of births during a period of the year when abiotic conditions are favorable) and shows that females are highly synchronized (>72% of births in a 3-month period) but the effects of environmental zeitgebers on reproduction are overridden by biological factors. Specifically, biotic and abiotic factors including (i) loss of immature offspring; (ii) population density; (iii) age at delivery; (iv) rainfall; and (v) changes in colony management were modeled in relation to the annual onset of births and the median birth date. Females experiencing loss of immature offspring had an interbirth interval of <365 days in average and the proportion of these females increased up to 48% due to changes in colony management overtime, although reproductive synchrony increased with increasing population density. A secular trend in both the onset of births and the median date of birth is documented and the model predicts that the median birth date will advance across all calendar-based seasons by 2050. The secular trend in reproduction appears to be triggered by changes in the age at delivery of females, the absence of physiological constraints from maternal investment due to offspring loss, shorter interbirth interval, and a higher degree of coordination due to increasing population density. This study challenges the reproductive phenology previously described for rhesus macaques highlighting the importance of long-term studies in addressing the ultimate causes of reproductive synchrony.

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A High Performance Liquid Chromatography (HPLC) method was developed and validated to quantify sucrose (non-reducing sugar), glucose, and fructose (reducing sugars) in raw tubers of Solanum tuberosum Group Phureja. Chromatographic analysis was performed using an AMINEX HPX 87H column, at 18 °C, linked to a refraction index detector, at 35 °C. The eluent was 10mM sulfuric acid. The conditions established for the method provided an optimum separation of sugars, citric acid, and malic acid, with resolution values higher or equal to one. Among the four sugar extraction methods tested, the double 50% (v/v) aqueous methanol extraction gave the highest level of analytes. Recovery of this extraction method ranged between 94.14 and 99.77%. The HPLC method was validated for repeatability, reproducibility, linearity, and limits of detection, and quantification. Relative standard deviation was found to be lower than five, when testing repeatability and reproducibility, which is suitable considering a range of acceptability from 5.3 to 7.3. Additionally, the regression analyses supported the method linearity in a range of quantification from 3 to 100 mg/L with regression coefficients values greater than 0.998 for the three analytes. Limits of detection were 3.0 mg/L for the three sugars and limits of quantification were 2.0 mg/L for sucrose and 3.0 mg/L for glucose and fructose. Four Colombian commercial cultivars (Criolla Guaneña, Criolla Paisa, Criolla Galeras, and Criolla Colombia) and five landrace accessions from the Colombian Core Collection of Group Phureja were grown in the district of Usme (Bogotá) fields to analyze their sugar contents. Sucrose, glucose, and fructose contents were found ranging from 0.93 to 3.11 g/100 g tuber dried weight (DW), from 0.25 to 4.53 g/100 g tuber DW, and from 0.10 to 1.49 g/100 g tuber DW, respectively. Therefore, a high range in the variability of sugar contents was found among genotypes. However, the variability was low among technical replicates of the same genotype, revealing an accurate quantification of sugars in Group Phureja. This method can be used to assess the amount of reducing and non-reducing sugars accumulation in potato germplasm.

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Tetanus was a major cause of mortality in the free-ranging population of rhesus monkeys on Cayo Santiago prior to 1985 when the entire colony was given its first dose of tetanus toxoid. The immediate reduction in mortality that followed tetanus toxoid inoculation (TTI) has been documented, but the long-term demographic effects of eliminating tetanus infections have not. This study uses the Cayo Santiago demographic database to construct comparative life tables 12 years before, and 12 years after, TTI. Life tables and matrix projection models are used to test for differences in: (i) survival among all individuals as well as among social groups, (ii) long-term fitness of the population, (iii) age distribution, (iv) reproductive value, and (v) life expectancy. A retrospective life table response experiment (LTRE) was performed to determine which life cycle transition contributed most to observed changes in long-term fitness of the population post-TTI. Elimination of clinical tetanus infections through mass inoculation improved the health and well-being of the monkeys. It also profoundly affected the population by increasing survivorship and long-term fitness, decreasing the differences in survival rates among social groups, shifting the population's age distribution towards older individuals, and increasing reproductive value and life expectancy. These findings are significant because they demonstrate the long-term effects of eradicating a major cause of mortality at a single point in time on survival, reproduction, and overall demography of a naturalistic population of primates.

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La formación de relaciones derivadas a partir de un entrenamiento en discriminaciones condicionales es un fenómeno ampliamente demostrado en humanos. Sin embargo, no es infrecuente que se observen algunos casos de pobre desempeño en las pruebas de equivalencia o dificultades en el aprendizaje de las relaciones entre los miembros de la clase. Este estudio examina si los tipos perceptuales de respuesta a las condiciones estimulativas de la tarea experimental (estilos cognitivos de sensibilidad al campo visual) están relacionados con la variabilidad en el desempeño en pruebas de equivalencia. A través de la prueba de figuras enmascaradas (EFT), se evaluó el estilo cognitivo de 32 participantes y se examinó su desempeño en pruebas de equivalencia después de un entrenamiento con el procedimiento de igualación a la muestra respondiente. Las frecuencias observadas en tablas de contingencia y los análisis correlacionales entre el desempeño en las pruebas de equivalencia y las puntuaciones en la prueba EFT indican una asociación positiva entre el estilo de dependencia-independencia del campo visual y la formación de relaciones derivadas.

The formation of equivalence classes derived from exposure to conditional discrimination training is a widely demonstrated phenomenon in human research. However, low performance in equivalence tests and difficulties in the acquisition of relations among class members are not infrequent. The present study examined whether types of perceptual response to the experimental stimulus (the cognitive style of visual field sensitivity) are related to the variability observed in equivalence tests. The masked figures test (MFT) was used to determine the cognitive styles of 32 participants who were also exposed to equivalence tests after conditional discrimination training trials with a respondent matching-to-sample procedure. Observed frequencies, as reported in contingency tables, and correlation coefficients between performance in equivalence tests and MFT scores suggested a positive association between the cognitive style of visual field dependence-independence and the formation of equivalence classes.

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El fenómeno de bloqueo describe una circunstancia en la cual se impide o se dificulta el la transferencia de funciones entre eventos que se han presentado en una relación de contigüidad espacio-temporal. Desde una perspectiva teórica y empírica, el efecto bloqueo no debería predecirse en la adquisición de clases de estímulos aun cuando algunos de los estímulos de la misma clase se presenten simultáneamente. El presente estudio examina si la historia adicional de entrenamiento A-EI bien sea previa o posterior al entrenamiento con un estímulo muestra compuesto AX, es la variable crítica en la presentación del efecto bloqueo. Los desempeños obtenidos en las pruebas de bloqueo por los participantes de un grupo expuesto al procedimiento de bloqueo, un grupo expuesto al procedimiento de bloqueo invertido, y un grupo control, sugieren que el entrenamiento adicional con un solo elemento del compuesto no impide la inclusión de todos los estímulos dentro de la clase. Los casos en los que se observó el efecto bloqueo se interpretan en términos de tipos de percepciones elementales y configurales.

The blocking effect describes a circumstance which impedes function transfer among events that are part of a relation of spatiotemporal contiguity. However, theoretical and empirical evidence in stimulus class acquisition predicts that the blocking effect should not be observed even if some of the stimul11n the class are presented simultaneously as compound stimuli. The present study examines if additional A-EI training, whether prior or following training with a compound sample AX, constitutes a critical variable in the occurrence of the blocking effect. Performances in blocking tests by a group exposed to the blocking procedure, a group exposed to the backward blocking procedure and a control group were compared. Findings suggest that additional training with one member of the compound does not impede responding to all stimuli as members of the class. Instances where the blocking effect was observed are interpreted in terms of configural and elemental types of responding.

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This study examines if the blocking effect paradigm predicts causal judgments when consequences of events vary in valence and magnitude. The procedure consists on presenting participants with reports describing the positive or negative effects produced by different substances, when these are consumed either separately or simultaneously with others. Two groups of participants were exposed to high and low magnitude consequences, respectively. The extent to which behavior with respect to causal judgments is consistent with the predictions of the blocking effect was evaluated in in both groups using two types of questions. One of them asked whether or not substance X produced the effect, while the other one asked about the probability of substance X producing the effect. Differences in causal judgments as a product of logical or intuitive reasoning were examined. Even though the blocking effect was not observed, a significant interaction was obtained between the factors valence and experimental condition (blocking and control). Findings are discussed in terms of the differences between associative learning in humans and in non-human animals, and in terms of the theoretical differences between evaluative conditioning and predictive or causal conditioning.

El propósito de este proyecto es examinar si el modelo de bloqueo predice la atribución de juicios causales al variar la valencia y la magnitud de las consecuencias. El arreglo experimental consiste en la presentación de reportes sobre los efectos positivos y negativos que producen diferentes sustancias al ser consumidas solas o en conjunto con otras. Los participantes del primer grupo estuvieron expuestos a consecuencias de alta magnitud y los del segundo grupo, a consecuencias de baja magnitud. Se evaluó si la atribución de causalidad es consistente con las predicciones del efecto bloqueo mediante dos tipos de pregunta: una pregunta acerca si la sustancia X produce o no el efecto, y una pregunta sobre la probabilidad de que X produzca el efecto. Se examinaron las diferencias en los juicios causales cuando las atribuciones son producto del razonamiento lógico o intuitivo. Si bien no se observó evidencia del efecto bloqueo, se obtuvieron efectos de interacción entre los factores valencia y condición experimental (sustancias bloqueo y control). Se discuten los hallazgos en términos de las diferencias entre el aprendizaje asociativo en humanos y animales no humanos, y en términos de las implicaciones sobre las diferencias teóricas entre el condicionamiento evaluativo y el condicionamiento predictivo.

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Los estudios sobre equivalencia en humanos con habilidades verbales generalmente utilizan el procedimiento de igualación a la muestra e incluyen estímulos arbitrarios. En la gran mayoría de los estudios publicados no se observa un desempeño superior al criterio en todos los participantes de los grupos evaluados. Los casos de bajo desempeño usualmente no se interpretan y se discute la variabilidad en la adquisición de relaciones derivadas en humanos pocas veces. El propósito del presente estudio es examinar si pueden explicarse al menos parcialmente los bajos desempeños por la habituación a las condiciones estimulativas del arreglo experimental. Se comparan los resultados en las pruebas de equivalencia de un grupo expuesto a un procedimiento de igualación a la muestra respondiente, y un grupo expuesto al mismo procedimiento pero con un requerimiento de respuesta de observación durante algunos de los ensayos de entrenamiento. La inspección visual de los datos muestra que un número mayor de participantes del segundo grupo obtuvo una ejecución superior al criterio. Se discuten algunas implicaciones teóricas y procedimentales a partir del análisis de los reportes verbales de los participantes.

Traditionally, research studies on the formation of equivalence classes in verbally able individuals are conducted using arbitrary stimuli and a matching-to-sample procedure. However, a higher-than-criterion performance in equivalence tests is not usually observed in all participants of these studies. These data are not often interpreted and the implied variability in the acquisition of derived relations in humans is seldom discussed. The purpose of this study is to examine whether habituation to the stimulating conditions of the experimental preparation may account - at least partially - for low performances observed in equivalence tests. Results of participants in a group exposed to a respondent matching-to-sample procedure were compared to those of a group exposed to a similar procedure with an added observation response requirement on some of the training trials. Visual inspection of the data shows that a higher number of participants in the second group obtained above-criterion performances. Some additional theoretical and procedural implications are discussed based on the analysis of participants' verbal reports.

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Las explicaciones tradicionales de la conducta cultural se fundamentan en una perspectiva seleccionista. Sin embargo, varias discusiones teóricas se han preguntado sobre la misma y sobre la identificación de unidades de selección. Argumentaré que, si bien las propuestas centrales de Glenn constituyen una extensión valiosa de los principios operantes, el enfoque seleccionista ha entorpecido el desarrollo conceptual y empírico de la teoría. Se presenta un examen de las nociones fundamentales de la teoría de la evolución cultural; específicamente, una revisión de los conceptos de metacontingencias, contingencias conductuales entrelazadas, macrocontingencias y productos agregados, en términos de su contribución a una explicación válida y significativa del comportamiento cultural. Se sugiere que se requieren análisis experimentales funcionales para identificar el control de la conducta por parte de contingencias individuales o grupales, incluyendo los productos acumulados y agregados.

Current mainstream accounts of cultural behavior are strongly founded on a selectionist perspective. However, more than a few theoretical discussions have emerged regarding the appropriateness of the subject matter and the identification of units of selection. I argue that although Glenn's central formulations constitute a valuable extension of operant principles, the selectionist approach has hindered the theory's conceptual and empirical development. An examination of the fundamental notions included in the theory of cultural evolution is presented. Specifically, we review the concepts of metacontingencies, interlocking behavioral contingencies, macrocontingencies, and aggregate products in terms of their contribution to a valid and significant account of cultural behavior. It is suggested that experimental functional analyses are required to identify control of behavior by local contingencies or group consequences including cumulative and aggregate products.

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A functional class refers to a circumstance in which responding is controlled by features of stimuli that are common to all the class members. It is argued that an analysis of substitution of stimulus functions is needed to account for the acquisition of functional classes of different varieties. We examined the acquisition of classes of comparison stimuli presented in a standard matching to sample (MTS) preparation by exposing participants to three tests in which a contextual cue provided the basis for the formation of these classes. In this preparation the equivalence training and test phases served as a masking task that prevented the interference of naming processes or the development of rules describing the commonalities among target class members (comparison stimuli). Most of the participants showed responding with respect to one or more comparison classes even in the absence of specific operant training. Findings suggest that the function shared by a given set of stimuli may be acquired by another stimulus in the absence of operant reinforcement and without the involvement of verbal rules.

Se habla de adquisición de clases funcionales cuando el comportamiento es controlado por aquellas propiedades de los estímulos que son comunes a todos los miembros de la clase. Un análisis en términos de sustitución de funciones es necesario para explicar la adquisición de varios tipos de clases funcionales. En este estudio se examinó la adquisición de clases de estímulos comparadores en un entrenamiento estándar de igualación a la muestra, mediante la inclusión de un estímulo contextual diferente para cada clase de comparadores. Las fases de entrenamiento y pruebas de equivalencia sirvieron como una tarea de enmascaramiento para prevenir la interferencia de respuestas verbales con respecto a las relaciones entre el estímulo contextual y los comparadores durante el entrenamiento. Hubo respuestas respecto a una o más clases de comparadores para la mayoría de los participantes. Los hallazgos indican que la función compartida por los miembros de una clase puede ser adquirida por un estímulo arbitrario en ausencia de refuerzo y de respuestas verbales.

RESUMO

UNLABELLED: The reliability of medial plantar, sural, and superficial peroneal nerve conduction studies (NCS) has not been widely studied. These nerves are usually involved in distal sensory neuropathies and their serial study is relevant in the clinical setting. PURPOSE: To determine the inter- and intrarater reliability of superficial peroneal, sural, and medial plantar NCS in healthy participants. METHODS: Two raters performed the bilateral NCS twice in 20 healthy participants (23.5 +/- 3.5 years). Reliability was analyzed by the Bland-Altman method and intraclass correlation coefficient (ICC). Variability was established by the coefficient of variation. RESULTS: The Bland-Altman method showed a good level of intra- and interrater agreement for all nerves. The amplitude (rater 1) and latency of the medial plantar nerve and the amplitude of the sural nerve (rater 2) had an intrarater ICC of >or=0.75. Interrater analysis showed concordance levels between moderate and very low. The highest coefficients of variations were found for amplitude and the lowest for nerve conduction velocity. CONCLUSIONS: Although the Bland-Altman method confirmed a good intra- and interrater reliability of the studied nerves, ICC analyses showed mixed results. These statistical approaches are complementary, and each one has advantages and disadvantages that must be considered in their application and interpretation.

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