Estado actual de Cheracebus sp. (Primates: Pitheciidae) y de su hábitat entrelos ríos Tigre y Nanay, Amazonía peruana / Current status of Cheracebus sp. (Primates: Pitheciidae) and of its habitat between the Tigre and Nanay rivers, Peruvian Amazon

Resumen Con excepción de los bosques de la cuenca del río Itaya, área de influencia de la carretera Iquitos-Nauta y cuenca media de los ríos Nanay y Tigre, no hay información sobre el estado actual de la población y hábitat de Cheracebus sp., lo que motivó el desarrollo de este estudio cuyos objetivos estuvieron orientados a obtener más información sobre el estado actual de esta especie. Para ello, de mayo a noviembre del 2019 se realizaron censos por transecto lineal en bosques de las cuencas de los ríos Itaya, Nanay y Tigre. En 1659 km de longitud recorrida se avistaron 32 grupos de Cheracebus sp., de ellos, 17 correspondieron a la cuenca del río Nanay. Grupos con cuatro individuos se avistaron con más frecuencia en la cuenca del río Nanay; la abundancia relativa y la densidad poblacional fue ligeramente mayor en la cuenca del río Itaya con 0.3 grupos/10 km y 4.2 individuos/km2. En el área de estudio, los bosques están muy perturbados desde las orillas de los ríos y quebradas hasta aproximadamente 0.7 km al interior. La baja densidad poblacional de Cheracebus sp. es consecuencia de la alta presión de caza, en particular en la cuenca del río Tigre; a ella se suma la alta perturbación de los bosques por la extracción de árboles maderables y otros recursos, lo que estaría ocasionando escasez de recursos alimenticios para éste y otros primates.

Abstract With the exception of the forests of the Itaya river basin, the area of influence of the Iquitos-Nauta highway and the middle basin of the Nanay and Tigre rivers, there is no information on the current status of Cheracebus sp. populations and habitat, which motivated this study. The objectives were aimed at obtaining more information on Cheracebus sp. and the state of its populations. Linear transect censuses were conducted from May to November 2019 in forests of the Itaya, Nanay and Tigre river basins. In 1659 km of covered length, 32 groups were sighted; of them, 17 corresponded to the Nanay river basin. Groups with four individuals were seen more frequently in the Nanay river basin; relative abundance and population density were slightly higher in the Itaya river basin with 0.3 groups/ 10 km and 4.2 individuals/ km2. In the study area, forests are highly disturbed from the banks of rivers and streams up to approximately 0.7 km inland. The low population density of Cheracebus sp. is a consequence of high hunting pressure, particularly in the Tigre river basin; added to this is the high disturbance of the forests due to the extraction of timber trees and other resources; which would be causing a shortage of food resources for this and other primates.

Research progress and prospect of collaborative brain-computer interface for group brain collaboration / 生物医学工程学杂志

As the most common active brain-computer interaction paradigm, motor imagery brain-computer interface (MI-BCI) suffers from the bottleneck problems of small instruction set and low accuracy, and its information transmission rate (ITR) and practical application are severely limited. In this study, we designed 6-class imagination actions, collected electroencephalogram (EEG) signals from 19 subjects, and studied the effect of collaborative brain-computer interface (cBCI) collaboration strategy on MI-BCI classification performance, the effects of changes in different group sizes and fusion strategies on group multi-classification performance are compared. The results showed that the most suitable group size was 4 people, and the best fusion strategy was decision fusion. In this condition, the classification accuracy of the group reached 77%, which was higher than that of the feature fusion strategy under the same group size (77.31%

Tamaño del grupo, argumentación y lectura de tablas en estudiantes universitarios / Group size, argumentation and table reading in university students

Resumen La argumentación es una variable importante para entender el aprendizaje. Aunque hay varios artículos al respecto, su relación con el tamaño del grupo es una novedad. Se analiza la relación entre el tamaño del grupo (díada-tríada) y la distribución argumental (simétrica-asimétrica) en lectura de tablas de doble entrada, y su relación con el tipo de respuesta utilizada. Se utilizó un diseño cuasi-experimental de solo post-test en una muestra de 89 estudiantes universitarios. Los resultados muestran distribuciones argumentales simétricas en las díadas, mientras que las tríadas obtuvieron mayores valores de asimetría. No se encontraron relaciones significativas entre el tamaño del grupo y el tipo de respuesta final como así tampoco entre la distribución argumental y el tipo de respuesta. Esto indicaría que el tamaño del grupo afecta la posibilidad de las personas de aportar argumentos durante la interacción, así como el tipo de tarea condicionaría el tipo de argumentos empleados.

Abstract Argumentation is an important variable to understand the learning process. Despite there are several papers about it, its relation with the group size is a novelty. The relationship between the group size (dyad-triad) and the argument distribution (symmetric-asymmetric) in a double-entry table reading task, in addition to its relationship with the type of answer used, are analyzed. A quasi-experimental design was used with only a post-test, in a sample of 89 university students. The results show that the dyads obtained the highest values of symmetry, whereas the triads obtained higher values of asymmetry. No significant relationships were found between the group size and the final answers types, neither between the group size and the answer type. This would indicate that the size of the group affects the possibility of people to provide arguments during the interaction, as well as the type of task that would condition the type of arguments used.

Diversidad y abundancia de primates en bosques de baja y alta perturbación humana de Los Chilchos, Amazonas, Perú / Diversity and abundance of primates in low and high human disturbance forests of Los Chilchos, Amazonas, Peru

En los bosques montanos de Los Chilchos habitan cinco especies de primates, cuya situación actual, tamaño de grupo y abundancia son desconocidos, información que es indispensable para el manejo y la formulación e implementación de medidas de conservación. Afín de obtener información sobre los aspectos mencionados, fueron conducidos censos por transecto lineal entre junio y julio del 2017 en bosques de baja y alta perturbación antrópica. Como resultado de los censos fueron registrados 63 grupos pertenecientes a 5 especies. De ellos, 50 grupos correspondieron a los bosques de baja perturbación, siendo Aotus miconax y Ateles belzebuth los más observados con 21 y 17 grupos, respectivamente. Grupos más grandes se observaron en Cebus yuracus (promedio 17.0±5.0 individuos) y A. belzebuth (promedio 14.5±7.2 individuos) y más pequeños en A. miconax (promedio 2.6±0.7 individuos). Con excepción de Lagothrix flavicauda, la abundancia relativa y densidad poblacional fueron más altas en bosques de baja perturbación, demostrando así el buen estado de conservación, lo que no ocurre en bosques de alta perturbación. Entre los primates, la densidad más alta fue para A. miconax con 26.23 indiv./km² y más baja para Alouatta seniculus con 3.0 indiv./km². Lagothrix flavicauda fue registrada únicamente en bosque de alta perturbación, cuya abundancia relativa fue estimada en 0.1 grupos/ 10 km.

In the montane forests of Los Chilchos five species of primates inhabit, whose current situation, group size and abundance are unknown, which are indispensable for the management and formulation and implementation of conservation measures. In order to obtain information on the mentioned aspects, censuses were conducted by linear transect between June and July 2017 in forests of low and high anthropic disturbance. As a result of the censuses, 63 groups belonging to 5 species were registered. Of these, 50 groups corresponded to low disturbance forests, being Aotus miconax and Ateles belzebuth the most observed with 21 and 17 groups, respectively. Larger groups were observed in Cebus yuracus (average 17.0 ± 5.0 individuals) and A. belzebuth (average 14.5 ± 7.2 individuals) and smaller in A. miconax (average 2.6 ± 0.7 individuals). With exception of Lagothrix flavicauda, the relative abundance and population density were higher in low-disturbance forests, demonstrating thus the good conservation status, which does not occur in high-disturbance forests. Among primates, the highest density was for A. miconax with 26.23 indiv. /km² and the lowest for Alouatta seniculus with 3.0 indiv./km². Lagothrix flavicauda was recorded only in high disturbance forest, whose relative abundance was estimated at 0.1 groups / 10 km.

Facilitation of web-based internet PBL: What is an adequate group size?

Background: Development in internet technology enables e-learning at the higher education level. We have developed the Internet PBL-Tutorial System/Rakuichi that allows multi-directional communication among participants with web-based bulletin boards. Although this system has been successful in medical education at the undergraduate level, we sought to encourage “readonly members” to participate more fully in the program. Methods: To this end, we compared the posting frequency among three strategies: (1) students and tutors had an off-site meeting to promote face-to-face communication during the course, (2) several classes were allowed to watch the discussion in other classes in the second half of the course, (3) three classes (5 – 6 students each) in one topic were combined into one class (16 students) in the second half. Results: No meaningful effects were observed for strategies (1) or (2). However, the posting frequency increased 50 % for strategy (3). Conclusion: Facilitation of communication among participants was achieved by increasing the number of student participants. We predicted that an optimal number of students in each class in internet-based PBL would be ~20 people.

Group size and composition of Guiana dolphins (Sotalia guianensis) (Van Bénèden, 1864) in the Paranaguá Estuarine Complex, Brazil / Tamanho e composição de grupos do boto-cinza (Sotalia guianensis) (Van Bénèden, 1864) no Complexo Estuarino de Paranaguá, Brasil

The aim of the present study was to describe the characteristics of Guiana dolphins (S. guianensis) group size and composition in the Paranaguá Estuarine Complex (25° 15' -25° 36' S and 48° 02'-48° 45' W), Paraná State, as well as to verify the existence of relationships between a given environmental variable (water depth, salinity, transparency and temperature) and group size. An area of around 124 km² was surveyed by boat from April 2006 to February 2008 in the following subsets of the estuary: Canal do Superagui (~28 km²), Pinheiros bay (~34 km²), part of Laranjeiras bay, which included the Guaraqueçaba sub-estuary (~38 km²), and part of the Mixture Section of the Paranaguá Estuarine Complex (~24 km²). In 45 survey days, a total of 147 hours were spent observing 286 groups of S. guianensis. Groups varied from two individuals to aggregations of up to 90 individuals (mean ± SD: 11.5 ± 14.4 individuals). Solitary individuals were seen only on five occasions (1.7 percent of all observations). Groups with calves (n = 247) represented 86.4 percent overall and were more common in all sub-areas when compared to groups without calves. Groups without calves were found in all sub-areas and were usually smaller and composed of up to 12 individuals. A usual group composition of 70 percent of adults and 30 percent of calves was observed considering all sub-areas and seasons. No correlations were found between group size and water temperature (Spearman's rank test, r = 0.0059, p = 0.9338), transparency (Spearman's rank test, r = 0.0597, p = 0.9333), depth (Spearman's rank test, r = 0.1421, p = 0.4698), and salinity (Spearman's rank test, r = -0.1938, p = 0.0665). While Guiana dolphin groups were seen in the entire surveyed area, group size varied significantly among the three main surveyed sub-areas (Kruskal Wallis, H2,196 = 29.85, p = 0.0000). Groups were larger in Laranjeiras bay and smaller in Canal do Superagui. The physical environment, risk ...

O objetivo do presente estudo foi descrever as características do tamanho e da composição de grupos do boto-cinza (S. guianensis) no Complexo Estuarino de Paranaguá (25° 15'-25° 36' S and 48° 02'-48° 45' O), Estado do Paraná, assim como de verificar a possível existência de relações entre uma dada variável ambiental (profundidade, salinidade, transparência e temperatura da água) e o tamanho de grupo. Uma área de aproximadamente 124 km² foi investigada com uso de barco a motor entre abril de 2006 e fevereiro de 2008 nas seguintes sub-áreas do estuário: Canal do Superagui (~28 km²), baía dos Pinheiros (~34 km²), parte da baía das Laranjeiras que incluiu o sub-estuário de Guaraqueçaba (~38 km²), e parte da Seção de Mistura do Complexo Estuarino de Paranaguá (~24 km²). Em 45 dias de investigação, um total de 147 horas foi empregado na observação de 286 grupos de S. guianensis. Numericamente os grupos variaram entre dois e 90 indivíduos (média ± DP: 11,5 ± 14,4 indivíduos). Indivíduos solitários foram observados em apenas cinco ocasiões (1,7 por cento de todas as observações). Grupos com filhotes (n = 247) representaram 86,4 por cento de todos os observados e foram mais comuns em todas as sub-áreas quando comparados com grupos sem filhotes. Grupos sem filhotes foram geralmente compostos por até 12 indivíduos e encontrados em todas as sub-áreas. Uma comum composição de grupo de cerca de 70 por cento de adultos e 30 por cento de filhotes foi observada considerando todas as sub-áreas e estações do ano. Não foram apontados correlações entre o tamanho de grupo e a temperatura (Teste de Rank de Spearman, r = 0,0059; p = 0,9338), a transparência (Teste de Rank de Spearman, r = 0,0597; p = 0,9333), a profundidade (Teste de Rank de Spearman, r = 0,1421; p = 0,4698), e a salinidade da água (Teste de Rank de Spearman, r = -0,1938; p = 0,0665). Enquanto grupos de botos-cinza foram observados ao largo de todo o estuário, seus tamanhos variaram significativamente ...

Grandes grupos: dinâmica e terapia / Large groups: dynamic and therapy / Grandes grupos: dinámica y terapia

Este trabalho tem o objetivo de localizar o início dos trabalhos na Inglaterra com grandes grupos, praticamente desconhecidos dentro de uma perspectiva psicanalítica no Brasil, apresentando as pioneiras contribuições de John Rickman e Pierre Turquet, que culminaram com a postulação em 1975, de um quarto suposto básico - a teoria de Oneness - presente em grandes grupos não estruturados. O artigo ressalta a importância da psicoterapia analítica de grupo voltar-se para a pesquisa teórica e a prática com grandes grupos que trazem interessantes perspectivas na atualidade para o trabalho grupal, que envolvem violência, trauma ou situações de conflito intra e inter grupais. Vale assinalar que estes trabalhos vêm sendo conduzidos em diversos países da Europa.

This paper aims to present the first works conduced with Large Groups in England, almost unknown within a psychoanalytical view in Brazil, presenting the pioneering contributions of John Rickman and Pierre Turquet, who postulated in 1975, a fourth basic assumption - Theory of Oneness - presented in unstructured large groups. This article emphasizes the importance of group-analytic psychotherapy to turn to theoretical research and practice with large groups who bring interesting perspectives to contemporary group work, involving violence, trauma and conflict within and between groups. It is worth noting that these studies have been conducted in several countries in Europe.

Este trabajo tiene como objecto es de localizar el início de los trabajos en Inglaterra con grandes grupos, practicamente desconocidos en Brasil, presentando las pioneras contribuiciones de John Rickman e Pierre Turquet que culminaran con la postulacion en 1975, el quarto supuesto básico - la teoria de Oneness - presente en grandes grupos no estructurados. El artigo resalta la importáncia de la pisicoterapia analítica del grupo volverse para la investigacíon teórica y la practica con grandes grupos que traén interesantes perpectivas en la actualidad para el trabajo en grupo, que involucran la violencia, traumas o situaciones de conflito intra y inter los grupos. Vale señalar que estos trabajos vienem siendo conducidos en diversos paises de Europa.

Densidad y estatus poblacional de monos aulladores rojos en un guadual, fragmento aislado, La Tebaida, Quindío, Colombia / Densidade e estado populacional de macacos guariba vermelho num bambusal, fragmento isolado, "La Tebaida, Quindío", Colômbia / Density and population status of red howler monkeys in an isolated bamboo forest fragment in La Tebaida, Quindío, Colombia

Gran parte de los remanentes boscosos alrededor de 1000 m de altitud en el eje cafetero Colombiano, son guaduales, bosques con predominio de bambú espinoso Guauda spp. Estos remanentes sostienen las últimas poblaciones de monos aulladores rojos en la franja entre 800 y 1300 m de altitud en la Cordillera Central Colombiana. Objetivo: Evaluar el estado poblacional de aulladores en un fragmento de guadua de 51,4 ha a 1100 m en el Quindío. Métodos y resultados: Se estimó por conteo directo una densidad ecológica de 163,4 individuos y 16,9 grupos/km2, la cual es superior a la normalmente reportada para la especie en bosques continuos, pero similar a la estimada en fragmentos aislados de bosques de montaña. A pesar de la alta densidad, los grupos presentaron un tamaño y composición similar a los registrados para la especie, con mayor número de individuos inmaduros que de hembras adultas (1,13:1) sugiriendo que la población se encuentra en condiciones estables. Se estimó una abundancia de solo 84 aulladores en el fragmento...

Density and population status of red howler monkeys in an isolated bamboo forest fragment in La Tebaida, Quindío, Colombia.The majority of forest remnants in the coffee growing region in Colombia are guaduales, forests with a predominance of thorny bamboos (Guadua spp.). These remnants support the last remaining populations of red howler monkeys found between 800 and 1,300 m of altitude in the Central Cordillera of Colombia. Objective: To assess the population status of howler monkeys in a 51.4 ha-bamboo forest fragmentat 1,100 m of altitude. Methods and results: The estimated howler population density in the fragment, based on direct counts, was of 163.4 individuals and 16.9 groups per km2, which is higher than that commonly reported for this species in continuous forests, although similar to the estimated density in isolated fragments of mountain forests. In spite of the high density, the group size and composition are similar to those usually reported for this species, with more immature individuals than female adults (1.13:1). This finding suggests that the population is under a stable condition. We estimated an abundance of just 84 howlers in the fragment. The guadual, narrow and elongated, is isolated by surrounding productive systems and has a low plant diversity. Nevertheless, guadua plants provide a suitable structure for the displacement and shelter of howlers. Conclusion: Our results demonstrate the tolerance of this species to the fragmentation and its plasticity in persisting in altered environments. However, the high density of individuals, low plant diversity, forest isolation, edge effect, and close contact with anthropic productive systems, are all possible threats to the persistence of this population...

Densidade e estado populacional de macacos guariba vermelho num bambusal, fragmento isolado, “La Tebaida, Quindío, Colômbia. Grande parte dos remanentes de floresta próximos a 1000m de altitude na região cafeteira da Colômbia são bambusais, florestas com predomínio de bambu espinhoso Guauda spp. Estes remanentes mantêm as últimas populações de macacos guariba vermelho entre 800 e 1300m de altitude na Cordilheira Central Colombiana. Objetivo: Avaliar o estado populacional de guaribas num fragmento de bambu de 51,4ha a 1100m em Quindío. Métodos e resultados: Estimou-se por contagem direta uma densidade populacional de 163,4 indivíduose 16,9 grupos/km2, a qual é superior à reportada normalmente para a espécie em florestas contínuas, mas semelhante à estimada em fragmentos isolados de floresta de montanha. Apesar da alta densidade, os grupos apresentaram tamanhos e composição similar a aquelesregistrados para a espécie, com maior número de indivíduos imaturos do que de fêmeas adultas (1,13:1) sugerindo que a população está em condições estáveis. Estimou-se a abundância em apenas 84 guaribas no fragmento. O bambusal, estreito e alongado, encontra-se isolado entre sistemas produtivos e é pouco diverso. No entanto, o bambu fornece a estrutura necessária para o deslocamento e refúgio para osguaribas. Conclusão: Estes resultados demonstram a tolerância desta espécie à fragmentação e à sua flexibilidade para persistir em ambientes perturbados. No entanto, a alta densidade de indivíduos, a baixa diversidade de plantas, o isolamento da floresta, o efeito de borda e o estreito contacto com sistemas produtivos antrópicos são possíveis ameaças para a persistência dessa população...

Efecto del espacio disponible/tamaño de grupo sobre el balance de nutrimentos en cerdos en finalización / Effect of the available space/group size on the nutrient balance of finishing pigs

The nitrogen and energy utilization of finishing pigs allocated individually or in groups of two was evaluated. Thirty two castrated males were used with an initial weight of 68.6 ± 1.0 kg that were assigned in a randomized complete block design with a split-plot arrangement in three treatments: a pig allocated individually with free access to feed and 0.81 m² of floor space (D1AL); two pigs allocated in group with free access to feed and 0.405 m² of floor space/pig (D2AL); a pig allocated individually paired-fed to the average consumption of pigs in D2AL and floor space similar to D1AL (D1P). The experiment was divided in two periods of excreta collection: days 1-4 and 18-21, respectively. There were eight repetitions per treatment. The nutrient consumption in period 1 was higher in D1AL compared to D2AL and D1P (density x period, P < 0.01); in period 2, the nutrient consumption was higher in D1AL, intermediate in D1P and lower in D2AL. The nitrogen (P < 0.05) and energy (P < 0.10) retained in period 1 was similar among densities (density x period interaction); in period 2 it was higher in D1AL compared to D2AL. The pigs housed in groups of two with free access to feed had lower nutrient consumption and retention at the end of the trial, probably as a consequence of chronic stress due to the competition for the feed, complicated by the restriction of available floor space.

Se evaluó la utilización de nitrógeno y energía en cerdos en finalización, alojados individualmente y en grupos de dos. Se usaron 32 machos castrados con un peso inicial de 68.6 ± 1.0 kg que fueron asignados al azar, en un diseño de bloques completos con arreglo en parcelas divididas en tres tratamientos: un cerdo alojado individualmente con libre acceso al alimento y 0.81 m² de espacio de piso (D1AL); dos cerdos alojados en grupo con libre acceso al alimento y 0.405 m² de espacio de piso/cerdo (D2AL); un cerdo alojado individualmente con consumo pareado con base en el consumo de los cerdos en D2AL y espacio de piso similar a D1AL (D1P). El experimento se dividió en dos periodos de recolección de excretas: días 1-4 (periodo 1) y 18-21 (periodo 2). Se tuvieron ocho repeticiones por tratamiento. El consumo de nutrimentos en el periodo 1 fue mayor en D1AL con respecto a D2AL y D1P (densidad x periodo, P < 0.01); en el periodo 2, el consumo de nutrimentos fue mayor en D1AL, intermedio en D1P y menor en D2AL. La retención de nitrógeno (P < 0.05) y de energía (P < 0.10) en el periodo 1 fue similar entre densidades (interacción densidad x periodo); en el periodo 2 fue mayor en D1AL comparado con D2AL. Los cerdos alojados en grupos de dos con alimentación a libertad tuvieron menor consumo y retención de nutrimentos en la fase final de la prueba, probablemente como consecuencia del estrés crónico debido a la competencia por el alimento, complicado por la restricción de espacio disponible de piso.

Notas sobre a distribuição, tamanho de grupo e comportamento do golfinho Tursiops truncatus (Cetacea: Delphinidae) na Ilha de Santa Catarina, sul do Brasil / Notes on the distribution, group size and behavior of the bottlenose dolphin,Tursiops truncatus(Cetacea: Delphinidae) in the coast of the Island of Santa Catarina, southern Brazil

A ecologia do golfinho-nariz-de-garrafa (Tursiops truncatus) é pouco documentada no Brasil. O objetivo deste trabalho é fornecer dados sobre a distribuição, tamanho de grupo e comportamento de T. truncatus a partir de avistagens oportunistas realizadas nas adjacências da Ilha de Santa Catarina, sul do Brasil. Em cada observação de grupos da espécie foram registrados: localidade, data e hora, tamanho de grupo e comportamento. Foram observados 71 grupos entre 1989 e 2005, em todos os meses do ano. A espécie foi observada em toda região costeira da Ilha de Santa Catarina, utilizando uma grande variedade de hábitats. O tamanho de grupo variou entre 1 e 200 indivíduos, com uma média de aproximadamente 8 indivíduos (moda = 2). Interações com pelo menos três espécies de aves marinhas também foram observadas, além de outros comportamentos. Os dados obtidos sugerem que a espécie é comum ao longo da costa da Ilha de Santa Catarina, possui uma grande plasticidade no uso de hábitats, além de um conjunto variado de comportamentos.

The ecology of the bottlenose dolphin (Tursiops truncatus) is scarcely documented in Brazil. The objective of this article is to present information about the distribution, group size and behavior of T. truncatus collected oportunistically around the Island of Santa Catarina. Locality, date and time, group size and behavior were registered after each opportunistic sighting. Seventy-one groups were observed between 1989 and 2005, in all months of the year. The species was sighted along all the coast of the island, using a great variety of habitats including protected bays and exposed beaches. Group size varied from 1 to 200 individuals, with a mean group size of approximately 8 individuals (mode = 2). Interactions with three species of sea birds were also documented. Data presented here suggest that the species is common around the Island of Santa Catarina, has a great plasticity in habitat use, and a varied behavior repertoire.

Reconocimiento preliminar de la densidad y estructura poblacional de Saguinus tripartitus Milne-Eduards en la Amazonía peruana

Censos por transecto fueron llevados a cabo en enero del 2005 en la cuenca del río Aushiri para determinar la densidad poblacional y estructura poblacional del «pichico dorado» (Saguinus tripartitus Milne-Eduards). Fueron registrados 17 grupos, cuya densidad poblacional fue calculada en 13,5 individuos/km². El tamaño de los grupos fluctuaron desde cuatro a ocho individuos y el tamaño promedio fue 5,3 individuos/ grupo. Cada grupo estuvo integrado por la pareja reproductora y su progenie de dos a seis individuos. Los adultos conformaron el 75% de la población.

Censuses by transects were carried out in January of the 2005 in the Aushiri river basin to determine the population density and population structure of the «golden-mantle tamarin» (Saguinus tripartitus Milne-Eduards). We recorded 17 groups and population density was calculated in 13,5 individuals/km². The size of the groups varied from four to eight individuals, with an average size of 5,3 individuals per group. The basic composition of a group was that of a reproductive pair with progeny of two to six individuals. The adults represented 75% of the total population.

Appropriate Group Size for Small-Group Learning / 医学教育

We examined appropriate group size and related factors in a small-group learning system conducted in a single department with sociomedical themes. The students were randomly divided into 4-and 6-person groups, and results of evaluations of the students and teaching staff were compared. The results suggest that the smaller the group, the more committed the students are to studying. Furthermore, teaching staff should participate in group discussion to deal with inactive students or to improve group dynamics.