892 research outputs found
Synthesizing greenhouse gas fluxes across nine European peatlands and shrublands: responses to climatic and environmental changes
In this study, we compare annual fluxes of methane
(CH4), nitrous oxide (N2O) and soil respiratory carbon dioxide
(CO2) measured at nine European peatlands (n = 4) and
shrublands (n = 5). The sites range from northern Sweden
to Spain, covering a span in mean annual air temperature
from 0 to 16 �C, and in annual precipitation from 300 to
1300mmyr−1. The effects of climate change, including temperature
increase and prolonged drought, were tested at five
shrubland sites. At one peatland site, the long-term (>30 yr)
effect of drainage was assessed, while increased nitrogen deposition
was investigated at three peatland sites.
The shrublands were generally sinks for atmospheric CH4,
whereas the peatlands were CH4 sources, with fluxes ranging
from −519 to +6890 mgCH4-Cm−2 yr−1 across the studied
ecosystems. At the peatland sites, annual CH4 emission
increased with mean annual air temperature, while
a negative relationship was found between net CH4 uptake
and the soil carbon stock at the shrubland sites. Annual
N2O fluxes were generally small ranging from −14
to 42 mgN2O-Nm−2 yr−1. Highest N2O emission occurred
at the sites that had highest nitrate (NO−
3 ) concentration
in the soil water. Furthermore, experimentally increased
NO−
3 deposition led to increased N2O efflux, whereas prolonged
drought and long-term drainage reduced the N2O efflux.
Soil CO2 emissions in control plots ranged from 310
to 732 gCO2-Cm−2 yr−1. Drought and long-term drainage generally reduced the soil CO2 efflux, except at a hydric
shrubland where drought tended to increase soil respiration.
In terms of fractional importance of each greenhouse gas
to the total numerical global warming response, the change in
CO2 efflux dominated the response in all treatments (ranging
71–96 %), except for NO−
3 addition where 89% was due to
change in CH4 emissions. Thus, in European peatlands and
shrublands the effect on global warming induced by the investigated
anthropogenic disturbances will be dominated by
variations in soil CO2 fluxes
Recolección de hongos comestibles silvestres en el contexto del pastoreo de alta montaña en la localidad de Agua Blanca en el Nevado de Toluca, México
Objective: Describe the collection of wild edible mushrooms that occurs in the rainy season in Agua Blanca, located in the Area of Protection of Flora and Fauna Nevado de Toluca
Design, methodology and approximation: Simple case study with qualitative perspective and ethnomethodological approach.
Results: They were detected 57 species of wild edible mushrooms that are collected in the context of high mountain grazing, being the production and management of sheep the main productive and economic activity in which they spend their time, alternating this activity with the mushrooms harvesting in rainy season.
Limitations and implications: It is a descriptive and exploratory work that only allows contributing to the documentation of the phenomenon within the study area.
Findings and conclusions: Mushroom harvesting is a complementary activity to livestock grazing and an opportunity to obtain extra income that allows families to survive during this season.Objetivo: Describir la recolección de hongos comestibles silvestres que se da en temporada de lluvias en la localidad Agua Blanca, ubicada en el Área de Protección de Flora y Fauna Nevado de Toluca
Diseño, metodología y aproximación: Estudio de caso simple con perspectiva cualitativa y aproximación etnometodológica.
Resultados: Fueron detectadas 57 especies de hongos comestibles silvestres que se recolectan en el contexto de pastoreo de alta montaña, siendo la producción y manejo de ganado ovino la principal actividad productiva y económica en la que emplean su tiempo, alternando esta actividad con la recolección de hongos en temporada de lluvias.
Limitaciones e implicaciones: Se trata de un trabajo descriptivo y exploratorio que sólo permite contribuir a la documentación del fenómeno dentro del área de estudio.
Hallazgos y conclusiones: La recolección de hongos es una actividad complementaria al pastoreo del ganado y una oportunidad de obtener ingresos extras que permiten la subsistencia de las familias durante esta temporada
Rickettsia parkeri in Amblyomma triste from Uruguay
Our goal was to detect whether spotted fever group Rickettsia are found in the suspected vector of rickettsioses, Amblyomma triste, in Uruguay. Rickettsia parkeri was detected in A. triste, which suggests that this species could be considered a pathogenic agent responsible for human rickettsioses in Uruguay
Respuesta productiva y económica del reemplazo parcial de mazorca de maíz quebrado con maíz molido o melaza para vacas de doble propósito
The aim of the study was to assess the effect of partial replacement of cracked maize ears with ground maize (GM) or sugar cane molasses (SCM) in supplements for dual purpose cows. Eighteen (18) multiparous cows (414 ± 13 kg of body weight and 106 ± 32 d in milk) were randomly assigned to the treatments. Treatments were as follows: 1) Control supplement (CS) which consisted of 87% of cracked maize ears (CME), 11% soybean meal, and 2% urea; 2) Ground maize replacing 20% of CME in CS (GMS); 3) Sugar cane molasses replacing 18% of CME in the CS (MOS). Each cow received 5 kg/d of supplement DM, whereas their calves received 1.8 kg/d DM of the CS. The experiment lasted eleven weeks, and data were recorded once at the end of every week. Data were analysed using a linear mixed model as a completely randomized design. Net profit from milk and beef due to supplements were estimated using the partial budget approach. There were no differences (P>0.05) between treatments on milk composition, body conditions score, nor daily weight gain of cows and calves. However, compared to GM, CS shown greater (9.0 %, P0.05) entre los tratamientos sobre la composición de la leche, la condición corporal ni el aumento de peso diario de las vacas y terneros. Sin embargo, en comparación con el MM, el ST mostró mayor (9.0 %, P0.05) en las demás variables de respuesta. Los márgenes combinados de ganancias netas (ventas de leche y terneros), fueron 9 % mayores para el tratamiento con MCA en comparación con el resto de los suplementos
Measurement of the cross-section and charge asymmetry of bosons produced in proton-proton collisions at TeV with the ATLAS detector
This paper presents measurements of the and cross-sections and the associated charge asymmetry as a
function of the absolute pseudorapidity of the decay muon. The data were
collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with
the ATLAS experiment at the LHC and correspond to a total integrated luminosity
of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements
varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the
1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured
with an uncertainty between 0.002 and 0.003. The results are compared with
predictions based on next-to-next-to-leading-order calculations with various
parton distribution functions and have the sensitivity to discriminate between
them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables,
submitted to EPJC. All figures including auxiliary figures are available at
https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13
Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in √s=13 TeV pp collisions with the ATLAS detector
A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell W and Z bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of √s=13 TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139 fb−1. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015–2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full data set are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at the 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV
Local and Landscape Factors Determining Occurrence of Phyllostomid Bats in Tropical Secondary Forests
Neotropical forests are being increasingly replaced by a mosaic of patches of different successional stages, agricultural fields and pasture lands. Consequently, the identification of factors shaping the performance of taxa in anthropogenic landscapes is gaining importance, especially for taxa playing critical roles in ecosystem functioning. As phyllostomid bats provide important ecological services through seed dispersal, pollination and control of animal populations, in this study we assessed the relationships between phyllostomid occurrence and the variation in local and landscape level habitat attributes caused by disturbance. We mist-netted phyllostomids in 12 sites representing 4 successional stages of a tropical dry forest (initial, early, intermediate and late). We also quantitatively characterized the habitat attributes at the local (vegetation structure complexity) and the landscape level (forest cover, area and diversity of patches). Two focal scales were considered for landscape characterization: 500 and 1000 m. During 142 sampling nights, we captured 606 individuals representing 15 species and 4 broad guilds. Variation in phyllostomid assemblages, ensembles and populations was associated with variation in local and landscape habitat attributes, and this association was scale-dependent. Specifically, we found a marked guild-specific response, where the abundance of nectarivores tended to be negatively associated with the mean area of dry forest patches, while the abundance of frugivores was positively associated with the percentage of riparian forest. These results are explained by the prevalence of chiropterophilic species in the dry forest and of chiropterochorous species in the riparian forest. Our results indicate that different vegetation classes, as well as a multi-spatial scale approach must be considered for evaluating bat response to variation in landscape attributes. Moreover, for the long-term conservation of phyllostomids in anthropogenic landscapes, we must realize that the management of the habitat at the landscape level is as important as the conservation of particular forest fragments
Characterization of the SNAG and SLUG Domains of Snail2 in the Repression of E-Cadherin and EMT Induction: Modulation by Serine 4 Phosphorylation
Snail1 and Snail2, two highly related members of the Snail superfamily, are direct transcriptional repressors of E-cadherin and EMT inducers. Previous comparative gene profiling analyses have revealed important differences in the gene expression pattern regulated by Snail1 and Snail2, indicating functional differences between both factors. The molecular mechanism of Snail1-mediated repression has been elucidated to some extent, but very little is presently known on the repression mediated by Snail2. In the present work, we report on the characterization of Snail2 repression of E-cadherin and its regulation by phosphorylation. Both the N-terminal SNAG and the central SLUG domains of Snail2 are required for efficient repression of the E-cadherin promoter. The co-repressor NCoR interacts with Snail2 through the SNAG domain, while CtBP1 is recruited through the SLUG domain. Interestingly, the SNAG domain is absolutely required for EMT induction while the SLUG domain plays a negative modulation of Snail2 mediated EMT. Additionally, we identify here novel in vivo phosphorylation sites at serine 4 and serine 88 of Snail2 and demonstrate the functional implication of serine 4 in the regulation of Snail2-mediated repressor activity of E-cadherin and in Snail2 induction of EMT
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