Estudio comparativo entre el cultivo convencional y ecológico de trigo para alimentación animal

El objetivo de este estudio fue investigar las diferencias en el rendimiento productivo y el valor nutritivo entre el cultivo ecológico y convencional de trigo invernal para su utilización en alimentación animal. La producción de forraje fue determinada en el mes de mayo de tres años consecutivos y la producción de paja y grano se determinó en el mes de julio de los dos primeros años. Las muestras fueron secadas para determinar su composición química y su digestibilidad in vitro. Adicionalmente, 500 mg de cada muestra fueron incubados con 50 mL de líquido ruminal tamponado a 39°C. En estas incubaciones se midió la producción de gas a diferentes tiempos para estimar la cinética de fermentación y se analizaron los parámetros de fermentación tras 24 horas de incubación. La producción de forraje, grano y paja fue mayor en las parcelas convencionales que en las ecológicas. El contenido en proteína bruta fue más bajo en el cultivo ecológico que en el convencional, tanto para el forraje como para el grano. La digestibilidad in vitro fue similar para los dos tipos de cultivo y no existieron diferencias en la cinética de degradación ni en la producción de ácidos grasos volátiles. Los resultados indican que el cultivo ecológico provocó una disminución de la producción y en el contenido de proteína en el forraje y en los granos de trigo, pero no se observaron efectos en la degradación ruminal. Estos resultados indican que el sistema de cultivo del trigo afecta a su composición química y por ello debe realizarse una valoración previa del mismo cuando se utilice para alimentación animal.The objective of this study was to assess the differences in yield and nutritive value of organically and conventionally grown wheat crops as animal feeds. Forage yield was determined in May in three consecutive years and straw and grain yield was determined in July in the two first years. Samples were dried to determine their chemical composition and in vitro digestibility. Additionally, 500 mg of each sample were incubated with 50 mL of buffered rumen fluid at 39°C to estimate rumen fermentation kinetics and fermentation parameters after 24 hours. Forage, grain and straw yield was greater in conventionally grown crops than in organic ones. Crude protein content was lower in organically grown wheat, both for the forage or the grain. In vitro digestibility was similar in both types of cultures and there were no differences in degradation kinetics parameters or volatile fatty acids production. Results indicate that organic cultivation lead to a decrease in yield and crude protein content in forage and wheat grain, but there were no differences in their ruminal degradation. These results indicate that cultivation system affects chemical composition of wheat and, therefore, it is necessary to assess the nutritive value of organically grown cereals intended for animal feeding

Revealing hidden clonal complexity in Mycobacterium tuberculosis infection by qualitative and quantitative improvement of sampling

AbstractThe analysis of microevolution events, its functional relevance and impact on molecular epidemiology strategies, constitutes one of the most challenging aspects of the study of clonal complexity in infection by Mycobacterium tuberculosis. In this study, we retrospectively evaluated whether two improved sampling schemes could provide access to the clonal complexity that is undetected by the current standards (analysis of one isolate from one sputum). We evaluated in 48 patients the analysis by mycobacterial interspersed repetitive unit–variable number tandem repeat of M. tuberculosis isolates cultured from bronchial aspirate (BAS) or bronchoalveolar lavage (BAL) and, in another 16 cases, the analysis of a higher number of isolates from independent sputum samples. Analysis of the isolates from BAS/BAL specimens revealed clonal complexity in a very high proportion of cases (5/48); in most of these cases, complexity was not detected when the isolates from sputum samples were analysed. Systematic analysis of isolates from multiple sputum samples also improved the detection of clonal complexity. We found coexisting clonal variants in two of 16 cases that would have gone undetected in the analysis of the isolate from a single sputum specimen. Our results suggest that analysis of isolates from BAS/BAL specimens is highly efficient for recording the true clonal composition of M. tuberculosis in the lungs. When these samples are not available, we recommend increasing the number of isolates from independent sputum specimens, because they might not harbour the same pool of bacteria. Our data suggest that the degree of clonal complexity in tuberculosis has been underestimated because of the deficiencies inherent in a simplified procedure

Enfermedad funcional tiroidea en la población de edad avanzada

ObjetivoDescribir la prevalencia de enfermedad funcional tiroidea (EFT) y otras afecciones asociadasa ella en una población de edad avanzadaDiseñoEstudio descriptivo transversalEmplazamientoCentro de atención primaria urbanoPacientesMuestra representativa de toda la poblacion atendida con edad . 60 anosMediciones principalesVariables demográficas, antecedentes clínicos de enfermedad tiroidea y afecciones asociadas a ella, índice de masa corporal, tests reducidos para el diagnóstico de depresión y ansiedad, Mini-Mental Test, electrocardiograma, determinación de colesterol total y colesterol unido a lipoproteínas de baja densidad (cLDL) y determinación de tirotropina y tiroxina libre si ésta estaba alteradaResultadosSe estudio a 192 personas, un 56% mujeres, con un 53% de 60–69 anos y un 12% con edad superior a 79 anos. Un 10% tenia antecedentes de EFT previa. La prevalencia de EFT activa fue del 13% (10,41% hipotiroidismo subclinico, 0,52% hipotiroidismo clinico, 1,56% hipertiroidismo subclinico y 0,52% hipertiroidismo clinico). La prevalencia de nuevos diagnosticos de EFT fue del 4,1% (7 hipotiroidismos y 1 hipertiroidismo, todos subclinicos). En el hipotiroidismo, se detectaron durante el estudio, las siguientes enfermedades: un 43% de trastornos de ansiedad, un 38% de sindromes depresivos, un 28,5% de deterioros cognitivos, un 9,5% de demencias, un 26% de alteraciones electrocardiograficas, un 47,6% de obesidad y un 28,5% de colesterol total . 250 mg/dl. En el hipertiroidismo se detectaron: un 50% de sindromes depresivos, un 25% de deterioros cognitivos, un 25% de alteraciones electrocardiograficas y un 50% de obesidadConclusionesLa prevalencia de EFT en la población de edad avanzada es superior a la de la población general, con un predominio del hipotiroidismo, las enfermedades subclínicas y las mujeres. Respecto a las enfermedades clásicamente asociadas a la disfunción tiroidea, se han observado pocas diferencias entre la población afectada de EFT y la no afectada. El papel del médico de atención primaria es importante para disminuir el infradiagnósticoObjectiveTo describe the prevalence of functional thyroid pathology (FTP) and pathologies associated with it in an elderly populationDesignDescriptive, cross-sectional studySettingUrban primary care centrePatientsRepresentative sample of the entire population attended that was 60 years old or overMain measurementsDemographic variables, clinicalhistory of thyroid pathology and pathology associated with it, Body Mass Index, small tests for diagnosing depression and anxiety, the mini-mental test, electrocardiogram, determination of total cholesterol and LDL cholesterol, and of free thyrotrophin and thyroxin if it is disturbedResults192 people were studied, 56% women, 53% between 60 and 69 and 12% over 79 years old. 10% had a history of previous FTP. Prevalence of active FTP was 13% (10.41% sub-clinical hypothyroidism, 0.52% clinical hypothyroidism, 1.56% subclinical hyperthyroidism, and 0.52% clinical hyperthyroidism). Prevalence of new diagnoses of FTP was 4.1% (7 with hypothyroidism and 1 with hyperthyroidism, all sub-clinical). During the study the following pathology was detected in hypothyroidism sufferers: 43% anxiety disorder, 38% depressive syndrome, 28.5% cognitive deterioration, 9.5% dementia, 26% electrocardiographic disturbances, 47.6% obesity, and 28.5% with total cholesterol .250 mg/dL. In hyperthyroidism, 50% with depressive syndrome, 25% with cognitive deterioration, 25% with electrocardiographic disturbances, and 50% with obesity were detectedConclusionsFTP is more prevalent among theelderly than in the population as a whole, with predominance of hypothyroidism, subclinical pathology and among women. In terms of pathology traditionally linked to thyroid malfunction, few differences were found between the population affectedwith FTP and those not affected. Primary care doctors are important in reducing underdiagnosi

Modeling contact formation between atomic-sized gold tips via molecular dynamics

Quantum Matter and Optic

Ethics of controlled human infection to study COVID-19

Development of an effective vaccine is the clearest path to controlling the coronavirus disease 2019 (COVID-19) pandemic. To accelerate vaccine development, some researchers are pursuing, and thousands of people have expressed interest in participating in, controlled human infection studies (CHIs) with severe acute respiratory syndrome–coronavirus 2 (SARS-CoV-2) (1, 2). In CHIs, a small number of participants are deliberately exposed to a pathogen to study infection and gather preliminary efficacy data on experimental vaccines or treatments. We have been developing a comprehensive, state-of-the-art ethical framework for CHIs that emphasizes their social value as fundamental to justifying these studies. The ethics of CHIs in general are underexplored (3, 4), and ethical examinations of SARS-CoV-2 CHIs have largely focused on whether the risks are acceptable and participants could give valid informed consent (1). The high social value of such CHIs has generally been assumed. Based on our framework, we agree on the ethical conditions for conducting SARS-CoV-2 CHIs (see the table). We differ on whether the social value of such CHIs is sufficient to justify the risks at present, given uncertainty about both in a rapidly evolving situation; yet we see none of our disagreements as insurmountable. We provide ethical guidance for research sponsors, communities, participants, and the essential independent reviewers considering SARS-CoV-2 CHIs

Seleção de uma espécie embaixadora para educação ambiental e conservação da conectividade da paisagem

In this article we review the role of Chrysocyon brachyurus (Class Mammalia; Order Carnivora; Family Canidae) as an "ambassador species" and we propose the possibility of its implementation to promote environmental education and manage the conservation of cultural landscapes in Argentina. The maned wolf is a native vertebrate of South America; it present biological characteristics (large body size), ecological (occupy a significant part of the national territory, inhabit in largely of the ecoregions and overlap their distribution with another 18 medium and large threatened mammals) and sociocultural (charismatic and not representing a threat for the inhabitants), allow to appoint it an ambassador species. This species, categorized since 2019 at the national level as Vulnerable, is the wild canid that has led the largest number of educational campaigns with multiple strategies implemented in the last 20 years. The ambassador figure could become a very powerful tool in large-scale environmental education proposals.  En el presente artículo revisamos el rol de Chrysocyon brachyurus (Clase Mammalia; Orden Carnivora; Familia Canidae) como “especie embajadora” y proponemos la posibilidad de su implementación para impulsar la educación ambiental y gestionar la conservación de los paisajes culturales de la Argentina. El aguará guazú es un vertebrado nativo de América del Sur; presenta características biológicas (tamaño corporal grande), ecológicas (ocupa una parte importante del territorio nacional, habita en gran parte de las ecorregiones y superpone su distribución con otros 18 mamíferos medianos y grandes amenazados) y socioculturales (carismático y no representa una amenaza para los habitantes), permite designarla especie embajadora. Esta especie, categorizada desde el 2019 a nivel nacional como Vulnerable, es el cánido silvestre que ha encabezado el mayor número de campañas educativas con múltiples estrategias, implementadas en los últimos 20 años. La figura de embajador podría constituirse en una herramienta muy poderosa en propuestas de educación ambiental a gran escala.Neste artigo revisamos o papel de Chrysocyon brachyurus (Classe Mamífero; Ordem Carnívora; Família Canídeo) como “espécie embaixadora” e propomos a possibilidade de sua implementação para promover a educação ambiental e gerenciar a conservação de paisagens culturais na Argentina. O lobo-guará é um vertebrado autóctone da América do Sul; devido às suas características biológicas (grande porte corporal), características ecológicas (ocupando grande parte do território nacional, habita a maioria das ecorregiões, sobrepondo sua distribuição com 18 mamíferos de médio e grande porte ameaçados) e socioculturais (ser carismático e não representa uma ameaça para os habitantes), que favorecem propô-la como espécie embaixadora da gestão ambiental. Este canídeo, categorizado desde 2019 a nível nacional como vulnerável, é o canídeo selvagem que liderou o maior número de campanhas educativas com múltiplas estratégias, implementadas nos últimos 20 anos. Essa figura do embaixador pode se tornar uma ferramenta muito poderosa em propostas de educação ambiental em grande escala. &nbsp

Hepatocarcinoma sobre hígado ectópico peritoneal

El hepatocarcinoma (HCC) sobre hígado ectópico es una entidad rara. La mayoría de los casos son asintomáticos y se descubren de manera casual en una autopsia o laparoscopia. En ocasiones producen clínica como dolor abdominal o hemorragia intraabdominal. Se realiza revisión de la literatura y se presenta el caso de una mujer de 68 años diagnosticada de hepatocarcinoma sobre hígado ectópico peritoneal a raíz de un estudio por hipertransaminasemia leve asintomática. Ectopic hepatocellular carcinoma is a rare entity. Most cases are asymptomatic and are occasionally found during autopsy or laparoscopy. They may sometimes cause relevant clinical problems such as abdominal pain or intra-abdominal bleeding. In this clinical case report, we review the literature in order to decipher the case of a 68-year-old female with an ectopic hepatocellular carcinoma that arose from the peritoneum. The patient was diagnosed after being studied due to a mild asymptomatic hypertransaminasemia

Vibrational Properties of Nanoscale Materials: From Nanoparticles to Nanocrystalline Materials

The vibrational density of states (VDOS) of nanoclusters and nanocrystalline materials are derived from molecular-dynamics simulations using empirical tight-binding potentials. The results show that the VDOS inside nanoclusters can be understood as that of the corresponding bulk system compressed by the capillary pressure. At the surface of the nanoparticles the VDOS exhibits a strong enhancement at low energies and shows structures similar to that found near flat crystalline surfaces. For the nanocrystalline materials an increased VDOS is found at high and low phonon energies, in agreement with experimental findings. The individual VDOS contributions from the grain centers, grain boundaries, and internal surfaces show that, in the nanocrystalline materials, the VDOS enhancements are mainly caused by the grain-boundary contributions and that surface atoms play only a minor role. Although capillary pressures are also present inside the grains of nanocrystalline materials, their effect on the VDOS is different than in the cluster case which is probably due to the inter-grain coupling of the modes via the grain-boundaries.Comment: 10 pages, 7 figures, accepted for publication in Phys. Rev.

Negatively Charged Excitons and Photoluminescence in Asymmetric Quantum Well

We study photoluminescence (PL) of charged excitons ($X^-$) in narrow asymmetric quantum wells in high magnetic fields B. The binding of all $X^-$ states strongly depends on the separation $\delta$ of electron and hole layers. The most sensitive is the ``bright'' singlet, whose binding energy decreases quickly with increasing $\delta$ even at relatively small B. As a result, the value of B at which the singlet--triplet crossing occurs in the $X^-$ spectrum also depends on $\delta$ and decreases from 35 T in a symmetric 10 nm GaAs well to 16 T for $\delta=0.5$ nm. Since the critical values of $\delta$ at which different $X^-$ states unbind are surprisingly small compared to the well width, the observation of strongly bound $X^-$ states in an experimental PL spectrum implies virtually no layer displacement in the sample. This casts doubt on the interpretation of PL spectra of heterojunctions in terms of $X^-$ recombination