1,814 research outputs found
Una Aproximación al Metabolismo Social Agrario del Espacio Productivo Especializado en Banano y Cacao en el Contexto de la Revolución Verde. Costa Rica (1955-1973)
T
En este artículo mostramos las principales transformaciones socioecológicas ocurridas en el sistema agrario del Espacio Productivo Especializado en banano y cacao en Costa Rica entre 1955 y 1973, momento cumbre de la Revolución Verde. Dichas transformaciones supusieron una creciente dependencia de maquinaria e insumos químicos en los agroecosistemas en detrimento de los sistemas agrarios tradicionales de base orgánica. El análisis se desarrolla en la región de Costa Rica que el Censo Agropecuario de 1955 caracterizó como especializada en la producción de banano y cacao, y el concepto de Espacios Productivos Especializados construido por los investigadores. Dichos espacios presentan uno o dos cultivos dominantes desarrollados con miras a su comercialización internacional, aunque también se desarrollan otras actividades productivas y extractivas. Proponemos un análisis retroprospectivo para mostrar desde el enfoque del Metabolismo Social, y a partir del análisis de los flujos-fondo y las tasas de retorno energéticos, las diferentes lógicas de intercambio de energía y materiales que ocurrieron en el Espacio Productivo Especializado en banano y cacao.En este artículo mostramos las principales transformaciones socioecológicas ocurridas en el sistema agrario del Espacio Productivo Especializado en banano y cacao en Costa Rica entre 1955 y 1973, momento cumbre de la Revolución Verde. Dichas transformaciones supusieron una creciente dependencia de maquinaria e insumos químicos en los agroecosistemas en detrimento de los sistemas agrarios tradicionales de base orgánica. El análisis se desarrolla en la región de Costa Rica que el Censo Agropecuario de 1955 caracterizó como especializada en la producción de banano y cacao, y el concepto de Espacios Productivos Especializados construido por los investigadores. Dichos espacios presentan uno o dos cultivos dominantes desarrollados con miras a su comercialización internacional, aunque también se desarrollan otras actividades productivas y extractivas. Proponemos un análisis retroprospectivo para mostrar desde el enfoque del Metabolismo Social, y a partir del análisis de los flujos-fondo y las tasas de retorno energéticos, las diferentes lógicas de intercambio de energía y materiales que ocurrieron en el Espacio Productivo Especializado en banano y cacao.En este artículo mostramos las principales transformaciones socioecológicas ocurridas en el sistema agrario del Espacio Productivo Especializado en banano y cacao en Costa Rica entre 1955 y 1973, momento cumbre de la Revolución Verde. Dichas transformaciones supusieron una creciente dependencia de maquinaria e insumos químicos en los agroecosistemas en detrimento de los sistemas agrarios tradicionales de base orgánica. El análisis se desarrolla en la región de Costa Rica que el Censo Agropecuario de 1955 caracterizó como especializada en la producción de banano y cacao, y el concepto de Espacios Productivos Especializados construido por los investigadores. Dichos espacios presentan uno o dos cultivos dominantes desarrollados con miras a su comercialización internacional, aunque también se desarrollan otras actividades productivas y extractivas. Proponemos un análisis retroprospectivo para mostrar desde el enfoque del Metabolismo Social, y a partir del análisis de los flujos-fondo y las tasas de retorno energéticos, las diferentes lógicas de intercambio de energía y materiales que ocurrieron en el Espacio Productivo Especializado en banano y cacao
Modos de intervención estatal sobre la infancia y su relación con los derechos de niños, niñas y adolescentes
Si se repasa la historia de la relación de la ley con los niños y, en particular, de los diferentes movimientos de protección a la infancia desde sus lejanos comienzos en tiempos de la industrialización, se advierte que nadie en Occidente discutía entonces si era necesario que los niños tuvieran educación, casa, comida o familia. Los debates, a lo largo de los años, giraron en torno de quién era el obligado a garantizarlos y con qué alcance, en otras palabras, qué significaba “familia”, “casa” o “educación”, etc.; pero no se discutía que proteger a un niño tuviera que ver con esos componentes básicos que, en la terminología actual, integran el conjunto de los llamados “Derechos de los Niños”.Facultad de Ciencias Jurídicas y Sociale
Introducción: Costa Rica, hacia una historia ambiental-regional
Introducción: Costa Rica, hacia una historia ambiental-regiona
Introducción: Costa Rica, hacia una historia ambiental-regional
Introducción: Costa Rica, hacia una historia ambiental-regiona
Novel mutation identification and copy number variant detection via exome sequencing in congenital muscular dystrophy.
BACKGROUND: Congenital muscular dystrophy type 1A (MDC1A), also termed merosin-deficient congenital muscular dystrophy (CMD), is a severe form of CMD caused by mutations in the laminin α2 gene (LAMA2). Of the more than 300 likely pathogenic variants found in the Leiden Open Variant Database, the majority are truncating mutations leading to complete LAMA2 loss of function, but multiple copy number variants (CNVs) have also been reported with variable frequency. METHODS: We collected a cohort of individuals diagnosed with likely MDC1A and sought to identify both single nucleotide variants and small and larger CNVs via exome sequencing by extending the analysis of sequencing data to detect splicing changes and CNVs. RESULTS: Standard exome analysis identified multiple novel LAMA2 variants in our cohort, but only four cases carried biallelic variants. Since likely truncating LAMA2 variants are often found in heterozygosity without a second allele, we performed additional splicing and CNV analysis on exome data and identified one splice change outside of the canonical sequences and three CNVs, in the remaining four cases. CONCLUSIONS: Our findings support the expectation that a portion of MDC1A cases may be caused by at least one CNV allele and show how these changes can be effectively identified by additional analysis of existing exome data
Placental thrombosis in acute phase abortions during experimental Toxoplasma gondii infection in sheep
43 p.After oral administration of ewes during mid gestation with 2000 freshly prepared sporulated oocysts of T. gondii
isolate M4, abortions occurred between days 7 and 11 in 91.6% of pregnant and infected ewes. Afterwards, a
further infection was carried out at late gestation in another group of sheep with 500 sporulated oocysts. Abortions
happened again between days 9 and 11 post infection (pi) in 58.3% of the infected ewes. Classically, abortions in
natural and experimental ovine toxoplasmosis usually occur one month after infection. Few experimental studies
have reported the so-called acute phase abortions as early as 7 to 14 days after oral inoculation of oocysts, and
pyrexia was proposed to be responsible for abortion, although the underline mechanism was not elucidated. In the
present study, all placentas analysed from ewes suffering acute phase abortions showed infarcts and thrombosis in
the caruncullar villi of the placentomes and ischemic lesions (periventricular leukomalacia) in the brain of some
foetuses. The parasite was identified by PCR in samples from some placentomes of only one sheep, and no antigen
was detected by immunohistochemical labelling. These findings suggest that the vascular lesions found in the
placenta, and the consequent hypoxic damage to the foetus, could be associated to the occurrence of acute phase
abortions. Although the pathogenesis of these lesions remains to be determined, the infectious dose or virulence
of the isolate may play a role in their developmentS
Anesthesia of Epinephelus marginatus with essential oil of Aloysia polystachya: an approach on blood parameters
This study investigated the anesthetic potential of the essential oil (EO) of Aloysia polystachya in juveniles of dusky grouper (Epinephelus marginatus). Fish were exposed to different concentrations of EO of A. polystachya to evaluate time of induction and recovery from anesthesia. In the second experiment, fish were divided into four groups: control, ethanol and 50 or 300 mu L L-1 EO of A. polystachya, and each group was submitted to induction for 3.5 min and recovery for 5 or 10 min. The blood gases and glucose levels showed alterations as a function of the recovery times, but Na+ and K+ levels did not show any alteration. In conclusion, the EO from leaves of A. polystachya is an effective anesthetic for dusky grouper, because anesthesia was reached within the recommended time at EO concentrations of 300 and 400 mu L L-1. However, most evaluated blood parameters showed compensatory responses due to EO exposure.Fundacao de Amparo a Pesquisa do Estado do Rio Grande do Sul/Programa de Apoio a Nucleos de Excelencia (FAPERGS/PRONEX) [10/0016-8]; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) [470964/2009-0]; Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior, Brazil (CAPES)info:eu-repo/semantics/publishedVersio
Robust estimation of microbial diversity in theory and in practice
Quantifying diversity is of central importance for the study of structure,
function and evolution of microbial communities. The estimation of microbial
diversity has received renewed attention with the advent of large-scale
metagenomic studies. Here, we consider what the diversity observed in a sample
tells us about the diversity of the community being sampled. First, we argue
that one cannot reliably estimate the absolute and relative number of microbial
species present in a community without making unsupported assumptions about
species abundance distributions. The reason for this is that sample data do not
contain information about the number of rare species in the tail of species
abundance distributions. We illustrate the difficulty in comparing species
richness estimates by applying Chao's estimator of species richness to a set of
in silico communities: they are ranked incorrectly in the presence of large
numbers of rare species. Next, we extend our analysis to a general family of
diversity metrics ("Hill diversities"), and construct lower and upper estimates
of diversity values consistent with the sample data. The theory generalizes
Chao's estimator, which we retrieve as the lower estimate of species richness.
We show that Shannon and Simpson diversity can be robustly estimated for the in
silico communities. We analyze nine metagenomic data sets from a wide range of
environments, and show that our findings are relevant for empirically-sampled
communities. Hence, we recommend the use of Shannon and Simpson diversity
rather than species richness in efforts to quantify and compare microbial
diversity.Comment: To be published in The ISME Journal. Main text: 16 pages, 5 figures.
Supplement: 16 pages, 4 figure
Combined effects of time spent in physical activity, sedentary behaviors and sleep on obesity and cardio-metabolic health markers: a novel compositional data analysis approach
<div><p>The associations between time spent in sleep, sedentary behaviors (SB) and physical activity with health are usually studied without taking into account that time is finite during the day, so time spent in each of these behaviors are codependent. Therefore, little is known about the combined effect of time spent in sleep, SB and physical activity, that together constitute a composite whole, on obesity and cardio-metabolic health markers. Cross-sectional analysis of NHANES 2005–6 cycle on N = 1937 adults, was undertaken using a compositional analysis paradigm, which accounts for this intrinsic codependence. Time spent in SB, light intensity (LIPA) and moderate to vigorous activity (MVPA) was determined from accelerometry and combined with self-reported sleep time to obtain the 24 hour time budget composition. The distribution of time spent in sleep, SB, LIPA and MVPA is significantly associated with BMI, waist circumference, triglycerides, plasma glucose, plasma insulin (all p<0.001), and systolic (p<0.001) and diastolic blood pressure (p<0.003), but not HDL or LDL. Within the composition, the strongest positive effect is found for the proportion of time spent in MVPA. Strikingly, the effects of MVPA replacing another behavior and of MVPA being displaced by another behavior are asymmetric. For example, re-allocating 10 minutes of SB to MVPA was associated with a lower waist circumference by 0.001% but if 10 minutes of MVPA is displaced by SB this was associated with a 0.84% higher waist circumference. The proportion of time spent in LIPA and SB were detrimentally associated with obesity and cardiovascular disease markers, but the association with SB was stronger. For diabetes risk markers, replacing SB with LIPA was associated with more favorable outcomes. Time spent in MVPA is an important target for intervention and preventing transfer of time from LIPA to SB might lessen the negative effects of physical inactivity.</p></div
- …