291 research outputs found

    Balance regional de nitrógeno en el sistema de producción leche-forraje de la Comarca Lagunera, México

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    The intensive system of milk production in the Laguna Region is characterized by large farms with more tan 1,000 milking cows and irrigated areas for forage production. The objective of this study was to estimate the balance between manure nitrogen (N) added to the soil and the requirement of N for forage crops. SAGARPA statistics were reviewed about dairy cows inventory and forage production during 1999-2011. Manure production and N excretion were estimated using daily milk production, while the crop N requirement was estimated based on crop yield and crop N removal. Forages occupied 69 % of the irrigated area, with 89,500 ha. Forage production was 1.2 million t yr-1 dry matter (DM), while the N requirement was 15,070 t yr-1. The dairy cow inventory was 423,000, with 53 % lactating. Manure production in DM was 842,000 t yr-1, while the N excreted was 44,154 t yr-1. The regional balance expressed as [N incorporated – crop N requirement] was 187 kg ha-1, which represents an excess. Previous studies showed that a balance 150 kg ha-1. El sistema intensivo de producción de leche en la Comarca Lagunera se caracteriza por grandes explotaciones con más de 1,000 vacas en lactancia y áreas para la producción de forrajes de riego. El presente estudio tuvo como objetivo estimar el balance entre el nitrógeno (N) del estiércol incorporado al suelo y el requerimiento de N por los cultivos forrajeros. Se revisaron estadísticas de la SAGARPA sobre el inventario ganadero y producción de forrajes de 1999 a 2011. La producción de estiércol y la excreción de N se estimaron en función de la producción diaria de leche, mientras que el requerimiento de N de los cultivos forrajeros se estimó en base al rendimiento y a la extracción de N por los cultivos. Los forrajes ocuparon el 69 % de la superficie de riego, con 89,500 ha. La producción de forraje fue de 1.2 millones t año-1 en materia seca (MS), mientras que el requerimiento de N fue de 15,070 t año-1. El inventario lechero fue de 423,000 vacas, con 53 % en lactancia. La producción de estiércol en MS fue de 842,000 t año-1, mientras que el N excretado fue de 44,154 t año-1. El balance regional expresado como [N incorporado – requerimiento de N por forrajes] fue de 187 kg ha-1, lo cual representa un exceso. Estudios previos muestran que un balance 150 kg ha-1

    Efecto de la temperatura del agua sobre la constante de velocidad de reacción de los contaminantes en un humedal construido para el tratamiento de aguas residuales porcícolas

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    La temperatura es un factor importante en los procesos que se llevan a cabo en los sistemas biológicos. En los humedales la capacidad de remoción de contaminantes está delimitada por factores ambientales. El objetivo fue determinar el efecto de la temperatura del agua sobre la constante de velocidad de reacción de contaminantes en un humedal de flujo superficial construido (HFSC) para la remoción de contaminantes en aguas residuales porcícolas. El HFSC consistió en un canal de 9 m de longitud por 3 m de ancho, recubierto con geo-membrana de alta densidad (4 mm). El lecho del HFSC consistió en una capa de 30 cm de arena y arcilla, con vegetación nativa del área de estudio. Se llevaron a cabo 12 corridas experimentales entre enero de 2014 y diciembre de 2015, con un tiempo de retención hidráulico (TRH) de 10 días. La remoción promedio de la demanda química de oxígeno (DQO) fue de 75 y 74 %,  el promedio de remoción de nitrógeno (amonio) NH3-N de 65 y 69 %, mientras que el nitrógeno total (NT) presentó promedio de remoción de 69 y 63 %, mientras que la remoción del fósforo total (PT) presentó valores de 75 y 73 % en 2014 y 2015 respectivamente. La temperatura del agua durante la fase experimental osciló entre 13 y 22 °C. La remoción del NH3-N mostró la mayor dependencia de la temperatura del agua con valores de R2=0.8787 en 2014 y R2=0.8957 en 2015. La constante de reacción volumétrica (kv d-1) en 2014 osciló de 0.041 a 0.185 d-1 con una temperatura promedio en el humedal de 13 a 21 °C. Mientras k presentó un valor promedio de 2.60 cm d-1 en 2014, y en 2015 el valor obtenido fue de 3.22 cm d-1. Fue evidente que el valor de kvaumentó conforme la temperatura del agua se incrementó, lo cual indica que este factor tiene un efecto directo en la remoción del NH3-N

    Capacidad resolutiva de establecimientos de salud en la detección de la violencia de género

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    Con el objetivo de determinar los factores asociados a la capacidad resolutiva de establecimientos de salud en la detección de la violencia de género, se desarrolló un estudio descriptivo-transversal-correlacional. La muestra conformada por 256 prestadores de salud que laboran en dos hospitales y cinco centros de salud cabeceras de microrredes, fue determinada por la fórmula de proporciones para poblaciones finitas y seleccionadas por estratificación proporcional. Los instrumentos de recolección de datos fueron un cuestionario de características sociodemográficas, un test de conocimientos sobre las normas legales y protocolos en la prevención y atención de la violencia de género de Siendonés, la escala de actitud frente a la violencia de Chuquimajo (confiabilidad de 0,91 y 0,81, respectivamente) y una lista de cotejo que verifica el número de indicadores de capacidad resolutiva del establecimiento de salud. Los datos fueron procesados en el programa SPSS versión 23,0. Los resultados muestran el perfil de los prestadores de salud: edad promedio 38,1 ± 9,0 años, siendo en su mayoría adultos intermedios de sexo femenino, 43,0% son casados, con un tiempo laboral promedio de 9,68 ± 8 años. El nivel de conocimiento de los prestadores de salud fue alto y muy alto (39,8% y 15,6%, respectivamente), seguido de conocimiento medio (33,6%) y bajo (10,9%). El 83,6% de los prestadores tiene una actitud neutra frente a la violencia de género, y solo el 4,7% tiene una actitud favorable. El conocimiento sobre violencia de género correlacionó en forma positiva con la actitud del prestador para detectar violencia de género (p < 0,05). Amayor capacidad de detección de violencia física, mayor capacidad de detección de violencia sexual, mayor capacidad de referencia de casos de VG(p < 0,05).Amayor número de casos de VGreferidos por el prestador de salud, mayor conocimiento del protocolo y flujograma de atención (p < 0,05)

    Geographic patterns of tree dispersal modes in Amazonia and their ecological correlates

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    Aim: To investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoochory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser-availability hypothesis) and/or the availability of resources for constructing zoochorous fruits (resource-availability hypothesis). Time period: Tree-inventory plots established between 1934 and 2019. Major taxa studied: Trees with a diameter at breast height (DBH) ≥ 9.55 cm. Location: Amazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield. Methods: We assigned dispersal modes to a total of 5433 species and morphospecies within 1877 tree-inventory plots across terra-firme, seasonally flooded, and permanently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We performed an abundance-weighted mean pairwise distance (MPD) test and fit generalized linear models (GLMs) to explain the geographic distribution of dispersal modes. Results: Anemochory was significantly, positively associated with mean annual wind speed, and hydrochory was significantly higher in flooded forests. Dispersal modes did not consistently show significant associations with the availability of resources for constructing zoochorous fruits. A lower dissimilarity in dispersal modes, resulting from a higher dominance of endozoochory, occurred in terra-firme forests (excluding podzols) compared to flooded forests. Main conclusions: The disperser-availability hypothesis was well supported for abiotic dispersal modes (anemochory and hydrochory). The availability of resources for constructing zoochorous fruits seems an unlikely explanation for the distribution of dispersal modes in Amazonia. The association between frugivores and the proportional abundance of zoochory requires further research, as tree recruitment not only depends on dispersal vectors but also on conditions that favour or limit seedling recruitment across forest types

    Geography and ecology shape the phylogenetic composition of Amazonian tree communities

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    AimAmazonia hosts more tree species from numerous evolutionary lineages, both young and ancient, than any other biogeographic region. Previous studies have shown that tree lineages colonized multiple edaphic environments and dispersed widely across Amazonia, leading to a hypothesis, which we test, that lineages should not be strongly associated with either geographic regions or edaphic forest types.LocationAmazonia.TaxonAngiosperms (Magnoliids; Monocots; Eudicots).MethodsData for the abundance of 5082 tree species in 1989 plots were combined with a mega-phylogeny. We applied evolutionary ordination to assess how phylogenetic composition varies across Amazonia. We used variation partitioning and Moran's eigenvector maps (MEM) to test and quantify the separate and joint contributions of spatial and environmental variables to explain the phylogenetic composition of plots. We tested the indicator value of lineages for geographic regions and edaphic forest types and mapped associations onto the phylogeny.ResultsIn the terra firme and várzea forest types, the phylogenetic composition varies by geographic region, but the igapó and white-sand forest types retain a unique evolutionary signature regardless of region. Overall, we find that soil chemistry, climate and topography explain 24% of the variation in phylogenetic composition, with 79% of that variation being spatially structured (R2 = 19% overall for combined spatial/environmental effects). The phylogenetic composition also shows substantial spatial patterns not related to the environmental variables we quantified (R2 = 28%). A greater number of lineages were significant indicators of geographic regions than forest types.Main ConclusionNumerous tree lineages, including some ancient ones (&gt;66 Ma), show strong associations with geographic regions and edaphic forest types of Amazonia. This shows that specialization in specific edaphic environments has played a long-standing role in the evolutionary assembly of Amazonian forests. Furthermore, many lineages, even those that have dispersed across Amazonia, dominate within a specific region, likely because of phylogenetically conserved niches for environmental conditions that are prevalent within regions

    Geography and ecology shape the phylogenetic composition of Amazonian tree communities

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    Aim: Amazonia hosts more tree species from numerous evolutionary lineages, both young and ancient, than any other biogeographic region. Previous studies have shown that tree lineages colonized multiple edaphic environments and dispersed widely across Amazonia, leading to a hypothesis, which we test, that lineages should not be strongly associated with either geographic regions or edaphic forest types. Location: Amazonia. Taxon: Angiosperms (Magnoliids; Monocots; Eudicots). Methods: Data for the abundance of 5082 tree species in 1989 plots were combined with a mega-phylogeny. We applied evolutionary ordination to assess how phylogenetic composition varies across Amazonia. We used variation partitioning and Moran\u27s eigenvector maps (MEM) to test and quantify the separate and joint contributions of spatial and environmental variables to explain the phylogenetic composition of plots. We tested the indicator value of lineages for geographic regions and edaphic forest types and mapped associations onto the phylogeny. Results: In the terra firme and várzea forest types, the phylogenetic composition varies by geographic region, but the igapó and white-sand forest types retain a unique evolutionary signature regardless of region. Overall, we find that soil chemistry, climate and topography explain 24% of the variation in phylogenetic composition, with 79% of that variation being spatially structured (R2^{2} = 19% overall for combined spatial/environmental effects). The phylogenetic composition also shows substantial spatial patterns not related to the environmental variables we quantified (R2^{2} = 28%). A greater number of lineages were significant indicators of geographic regions than forest types. Main Conclusion: Numerous tree lineages, including some ancient ones (>66 Ma), show strong associations with geographic regions and edaphic forest types of Amazonia. This shows that specialization in specific edaphic environments has played a long-standing role in the evolutionary assembly of Amazonian forests. Furthermore, many lineages, even those that have dispersed across Amazonia, dominate within a specific region, likely because of phylogenetically conserved niches for environmental conditions that are prevalent within regions

    Mapping density, diversity and species-richness of the Amazon tree flora

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    Using 2.046 botanically-inventoried tree plots across the largest tropical forest on Earth, we mapped tree species-diversity and tree species-richness at 0.1-degree resolution, and investigated drivers for diversity and richness. Using only location, stratified by forest type, as predictor, our spatial model, to the best of our knowledge, provides the most accurate map of tree diversity in Amazonia to date, explaining approximately 70% of the tree diversity and species-richness. Large soil-forest combinations determine a significant percentage of the variation in tree species-richness and tree alpha-diversity in Amazonian forest-plots. We suggest that the size and fragmentation of these systems drive their large-scale diversity patterns and hence local diversity. A model not using location but cumulative water deficit, tree density, and temperature seasonality explains 47% of the tree species-richness in the terra-firme forest in Amazonia. Over large areas across Amazonia, residuals of this relationship are small and poorly spatially structured, suggesting that much of the residual variation may be local. The Guyana Shield area has consistently negative residuals, showing that this area has lower tree species-richness than expected by our models. We provide extensive plot meta-data, including tree density, tree alpha-diversity and tree species-richness results and gridded maps at 0.1-degree resolution

    Evolving trends in the management of acute appendicitis during COVID-19 waves. The ACIE appy II study

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    Background: In 2020, ACIE Appy study showed that COVID-19 pandemic heavily affected the management of patients with acute appendicitis (AA) worldwide, with an increased rate of non-operative management (NOM) strategies and a trend toward open surgery due to concern of virus transmission by laparoscopy and controversial recommendations on this issue. The aim of this study was to survey again the same group of surgeons to assess if any difference in management attitudes of AA had occurred in the later stages of the outbreak. Methods: From August 15 to September 30, 2021, an online questionnaire was sent to all 709 participants of the ACIE Appy study. The questionnaire included questions on personal protective equipment (PPE), local policies and screening for SARS-CoV-2 infection, NOM, surgical approach and disease presentations in 2021. The results were compared with the results from the previous study. Results: A total of 476 answers were collected (response rate 67.1%). Screening policies were significatively improved with most patients screened regardless of symptoms (89.5% vs. 37.4%) with PCR and antigenic test as the preferred test (74.1% vs. 26.3%). More patients tested positive before surgery and commercial systems were the preferred ones to filter smoke plumes during laparoscopy. Laparoscopic appendicectomy was the first option in the treatment of AA, with a declined use of NOM. Conclusion: Management of AA has improved in the last waves of pandemic. Increased evidence regarding SARS-COV-2 infection along with a timely healthcare systems response has been translated into tailored attitudes and a better care for patients with AA worldwide

    Consistent patterns of common species across tropical tree communities

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    Trees structure the Earth’s most biodiverse ecosystem, tropical forests. The vast number of tree species presents a formidable challenge to understanding these forests, including their response to environmental change, as very little is known about most tropical tree species. A focus on the common species may circumvent this challenge. Here we investigate abundance patterns of common tree species using inventory data on 1,003,805 trees with trunk diameters of at least 10 cm across 1,568 locations1,2,3,4,5,6 in closed-canopy, structurally intact old-growth tropical forests in Africa, Amazonia and Southeast Asia. We estimate that 2.2%, 2.2% and 2.3% of species comprise 50% of the tropical trees in these regions, respectively. Extrapolating across all closed-canopy tropical forests, we estimate that just 1,053 species comprise half of Earth’s 800 billion tropical trees with trunk diameters of at least 10 cm. Despite differing biogeographic, climatic and anthropogenic histories7, we find notably consistent patterns of common species and species abundance distributions across the continents. This suggests that fundamental mechanisms of tree community assembly may apply to all tropical forests. Resampling analyses show that the most common species are likely to belong to a manageable list of known species, enabling targeted efforts to understand their ecology. Although they do not detract from the importance of rare species, our results open new opportunities to understand the world’s most diverse forests, including modelling their response to environmental change, by focusing on the common species that constitute the majority of their trees.Publisher PDFPeer reviewe
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