Effects of experimental tail shortening on the phenotypic condition of barn swallows Hirundo rustica: Implications for tail-length evolution

Some studies have suggested that tail streamers in the barn swallow Hirundo rustica may have been elongated 10-12 mm by sexual selection, but according to other studies, the length of these feathers is at the aerodynamic optimum or very close to it. To shed light on this issue, outermost tail feathers were experimentally shortened in male and female barn swallows by 1, 11 or 21 mm. Changes in four physiological parameters commonly used to estimate phenotypic condition in birds (weight, erythrocyte sedimentation rate, blood leukocyte concentration and heterophil/lymphocyte ratio) were checked one month later. Health improved (blood leukocyte concentration decreased) in the group of birds with tails shortened by 11 mm (both males and females), but body condition deteriorated (weight decreased) compared to the other two experimental groups. There was no significant effect of tail-length manipulation on the other two physiological parameters. These contradictory results suggest trade-offs between components of phenotypic condition. Possible negative relationships between condition-related traits imply that using one or very few physiological parameters to estimate phenotypic condition might not be appropriate. The most plausible explanation for the turning point in phenotypic condition when streamers were shortened by 11 mm is that these feathers are 7-15 mm longer than the aerodynamic optimum in both sexes. Therefore, our results are consistent with the hypothesis that tail streamers have been elongated 10-12 mm by sexual selection. This conclusion disagrees with a previous study on the effect of experimental tail shortening on haematocrit, but the complexity of interpreting changes in haematocrit might account for this discrepancy. © 2014 The Authors.The study was funded by the Andalusian Regional Government (Acc. Coord. 2001) and by the Spanish Ministry of Science and Technology and the European Regional Development Fund (projects BOS2001-1717 and CGL2008-00137/BOS).Peer Reviewe

Evaluating the Robustness of Learning Analytics Results Against Fake Learners

Massive Open Online Courses (MOOCs) collect large amounts of rich data. A primary objective of Learning Analytics (LA) research is studying these data in order to improve the pedagogy of interactive learning environments. Most studies make the underlying assumption that the data represent truthful and honest learning activity. However, previous studies showed that MOOCs can have large cohorts of users that break this assumption and achieve high performance through behaviors such as Cheating Using Multiple Accounts or unauthorized collaboration, and we therefore denote them fake learners. Because of their aberrant behavior, fake learners can bias the results of Learning Analytics (LA) models. The goal of this study is to evaluate the robustness of LA results when the data contain a considerable number of fake learners. Our methodology follows the rationale of ‘replication research’. We challenge the results reported in a well-known, and one of the first LA/PedagogicEfficacy MOOC papers, by replicating its results with and without the fake learners (identified using machine learning algorithms). The results show that fake learners exhibit very different behavior compared to true learners. However, even though they are a significant portion of the student population (∼15%), their effect on the results is not dramatic (does not change trends). We conclude that the LA study that we challenged was robust against fake learners. While these results carry an optimistic message on the trustworthiness of LA research, they rely on data from one MOOC. We believe that this issue should receive more attention within the LA research community, and can explain some ‘surprising’ research results in MOOCs. Keywords: Learning Analytics, Educational Data Mining, MOOCs, Fake Learners, Reliability, IR

Concordancia de valores nutricionales entre la Antropometria y Bioimpedancia electrica en pacientes con insuficiencia cardiaca.

La Insuficiencia Cardiaca Crónica (ICC) se asocia frecuentemente con desnutrición y esta constituye un marcador independiente de mal pronóstico. La composición corporal de estos pacientes se ve alterada por los cambios fisiopatológicos; por ello es difícil realizar la evaluación nutricional y no existe un método que pueda ser utilizado en forma única y exclusiva; por ello realizamos un estudio observacional, transversal, descriptivo, en 30 pacientes con diagnóstico de ICC internados en el Hospital de Clínicas, Facultad de Ciencias Médicas, Universidad Nacional de Asunción, desde marzo del 2008 a marzo del 2009 con el objetivo de determinar la concordancia entre los resultados de evaluación nutricional estimada por variables antropométricas agrupadas en un score, en comparación a la Bio-impedanciometría (BIA). Los resultados nos muestran que existe un alto porcentaje de desnutrición e incluso caquexia cardiaca; siendo la frecuencia, variable de acuerdo al método de valoración nutricional utilizado. Comparando la evaluación nutricional según el score y la BIA observamos un bajo nivel de concordancia (índice kappa de 0,3). Pese a ello consideramos que la utilización del score seria de utilidad por ser un método fácil, rápido, económico

Sustainable Intensification in Crop-Livestock Systems

Extensive livestock production is the main animal source food system in the Pampas and Campos sub-regions in South America. Beef cattle and sheep convert forage biomass that humans cannot eat into nutrient-dense human-edible foods (meat and milk) and valuable co-products (wool). However, diverse global pressures are acting on Pampas systems including increasing demand for protein sources (food security), climate change, environmental footprint, and competition for land. The integration of small areas of pasture-crop rotations is an alternative for increasing efficiency and sustainable intensification of agroecosystems based on natural grasslands. Rotations led by improved pastures increase the carrying capacity and productivity of traditional Pampas systems, and include crop production (soybean, rice) as an opportunity for farm diversification and resilience. Therefore, mixed crop-livestock systems can feed more people in terms of calories and protein than what is possible with specialized systems. The higher carrying capacity in the area under the rotation may allow less intensive grazing management in larger areas of native grasslands reducing threats to biodiversity. Some of the integrated management practices in crop-livestock systems are perennial pastures to mitigate soil organic carbon losses during cropping, biological nitrogen fixation by legumes, grazing cover crops, crop residue grazing, dual-purpose crops, and harvesting grain and hay for livestock feed. Also, complementary crop and livestock production systems facilitate more efficient nutrient cycling and self-sufficient systems promoting the circular economy concept as a strategic approach toward system sustainability. Key to understanding the potential of mixed crop-livestock systems are productive, environmental, economic, and social factors that determine their performance, as well as trade-offs among them. Development, implementation, maintenance, and analysis of long-term crop-livestock platforms research provides science-based information to address complex biological systems, and to implement innovative public policies at national scale to regulate soil use and to prevent non-sustainable agricultural practices

Multimedia Retrieval by Means of Merge of Results from Textual and Content Based Retrieval Subsystems

The main goal of this paper it is to present our experiments in ImageCLEF 2009 Campaign (photo retrieval task). In 2008 we proved empirically that the Text-based Image Retrieval (TBIR) methods defeats the Content-based Image Retrieval CBIR “quality” of results, so this time we developed several experiments in which the CBIR helps the TBIR. The TBIR System [6] main improvement is the named-entity sub-module. In case of the CBIR system [3] the number of low-level features has been increased from the 68 component used at ImageCLEF 2008 up to 114 components, and only the Mahalanobis distance has been used. We propose an ad-hoc management of the topics delivered, and the generation of XML structures for 0.5 million captions of the photographs (corpus) delivered. Two different merging algorithms were developed and the third one tries to improve our previous cluster level results promoting the diversity. Our best run for precision metrics appeared in position 16th, in the 19th for MAP score, and for diversity value in position 11th, for a total of 84 submitted experiments. Our best and “only textual” experiment was the 6th one over 41

COMPARACIÓN FENOTÍPICA DE PLANTAS PROVENIENTES DE SEMILLAS DE SÉSAMO (Sesamum indicum L.), VARIEDAD ESCOBA BLANCA, DE DIFERENTES ORÍGENES.

El experimento se llevó a cabo en el Campo Experimental de la Facultad de Ciencias Agrarias de la Universidad Nacional de Asunción, en la ciudad de San Lorenzo, durante los años 2006 – 2007. El objetivo del trabajo fue evaluar la variabilidad presente en las características morfológicas y agronómicas de lotes de semillas de la variedad Escoba o Escoba Blanca, provenientes de semillas fiscalizadas y «semillas propias» de los indígenas del Chaco Central. El análisis estadístico de los datos se realizó mediante la Prueba de T para muestras independientes, con dos tratamientos, semillas fiscalizadas (SF) y semillas propias de los indígenas (SPI), cada uno con diez repeticiones. Ambos lotes fueron evaluados y caracterizados de acuerdo a los criterios basados en los descriptores de sésamo del IBPGR (1981). Los resultados muestran que aunque existen variaciones entre los lotes, ambos son considerados de la variedad Escoba Blanca. Los coeficientes de variación son mayores en las parcelas originadas de semillas fiscalizadas debido a que estas provienen de un solo ciclo de depuración mientras que, las semillas propias de los indígenas presentan menor variación debido al aislamiento en el cual la variedad fue cultivada por casi una década. Las características morfológicas son menos variables que las agronómicas

Biofilm development by clinical strains of non-pigmented rapidly growing mycobacteria

AbstractThe relationship between clinical significance of non-pigmented, rapidly growing mycobacteria (NPRGM), in vitro biofilm development and sliding motility was evaluated in this study. One hundred and sixty-eight clinical strains of NPRGM were included. Forty-one of these were clinically significant isolates. Biofilm was formed by 123 strains. Seventy-six biofilm-positive and 25 biofilm-negative strains showed sliding motility. There was a relationship between clinical significance and biofilm development (p <0.000 001), sliding motility (p 0.0037) and species (p <0.000 001). No relationship was found between motility and biofilm development. The ability to develop biofilm is a characteristic that can have importance in the development of infections caused by NPRGM

Severe Acute Respiratory Syndrome Coronavirus 2 Infection in Pregnancy. A Non-systematic Review of Clinical Presentation, Potential Effects of Physiological Adaptations in Pregnancy, and Placental Vascular Alterations

In December 2019, the novel Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) rapidly spread to become a pandemic. To date, increasing evidence has described the potential negative impact of SARS-CoV-2 infection on pregnant women. Although the pathophysiology of coronavirus disease 2019 (COVID-19) is not entirely understood, there is emerging evidence that it causes a severe systemic inflammatory response associated with vascular alterations that could be of special interest considering some physiological changes in pregnancy. Additionally, these alterations may affect the physiology of the placenta and are associated with pregnancy complications and abnormal histologic findings. On the other hand, data about the vaccine against SARS-CoV-2 are limited, but the risks of administering COVID-19 vaccines during pregnancy appear to be minimal. This review summarizes the current literature on SARSCoV2 virus infection, the development of COVID-19 and its relationship with physiological changes, and angiotensin-converting enzyme 2 (ACE2) function during pregnancy. We have particularly emphasized evidence coming from Latin American countries.Fil: Ayala Ramírez, Paola. Pontificia Universidad Javeriana; ColombiaFil: González, Marcelo. Universidad de Concepción; ChileFil: Escudero, Carlos. Universidad del Bio Bio; ChileFil: Quintero Arciniegas, Laura. Pontificia Universidad Javeriana; ColombiaFil: Giachini, Fernanda R.. Universidade Federal de Goiás; Brasil. Universidade Federal do Mato Grosso do Sul; BrasilFil: Alves de Freitas, Raiany. Universidade Federal de Goiás; BrasilFil: Damiano, Alicia Ermelinda. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; ArgentinaFil: García-Robles, Reggie. Pontificia Universidad Javeriana; Colombi