909 research outputs found
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
The ‘Palo a Pique’ Long-Term Research Platform: First 25 years of a Crop-Livestock Experiment in Uruguay
Mixed crop-livestock long-term experiments (LTE) are critical to increase the understanding of sustainability in complex agroecosystems. One example is the ‘Palo a Pique’ LTE which has been running for 25 years in Uruguay (1995 to present) evaluating four pasture-crop rotations under livestock grazing with no-till technology in soils with severe limitations. Results demonstrate that cropping systems reduced soil organic carbon (SOC) compared with permanent pastures, and that perennial pastures rotating with crops were critical to mitigate SOC losses. Data from the ‘Palo a Pique’ LTE has contributed to establish new national policies to secure sustainability of agricultural-based systems. Although the original purpose of the LTE was oriented to crops and soils, a demand for sustainable livestock intensification has gathered momentum over recent years. As a result, the current approach of the ‘Palo a Pique’ LTE matches each pasture-crop rotation with the most suitable livestock strategy with the common goal of producing 400 kg liveweight/ha per year. General approaches to the pursuit of sustainable livestock intensification include: shortening the cycle of production, diversifying animal categories, increasing liveweight gain and final animal liveweight, and strategic livestock supplementation. Prediction of trade-offs between environmental, economic, and production indicators can be addressed through monitoring and modelling, enabling timely anticipation of adverse sustainability issues on commercial farms. The ‘Palo a Pique’ LTE serves as a framework to address contemporary and future questions dealing with the role of ruminants on climate change, competition for land, nutrient dynamics, and food security
Orbital Magnetism in Ensembles of Parabolic Potentials
We study the magnetic susceptibility of an ensemble of non-interacting
electrons confined by parabolic potentials and subjected to a perpendicular
magnetic field at finite temperatures. We show that the behavior of the average
susceptibility is qualitatively different from that of billiards. When averaged
over the Fermi energy the susceptibility exhibits a large paramagnetic response
only at certain special field values, corresponding to comensurate classical
frequencies, being negligible elsewhere. We derive approximate analytical
formulae for the susceptibility and compare the results with numerical
calculations.Comment: 4 pages, 4 figures, REVTE
Transgender and Gender Diverse Clients’ Experiences in Therapy: Responses to Sociopolitical Events and Helpful and Unhelpful Experiences
We examined transgender and gender-diverse (TGD) people’s reports of their therapy experiences over the course of a year. We explored how participants’ therapists integrated discussions about current events, as well as their more general perspectives on helpful and unhelpful experiences. A total of 107 participants provided data on these questions at least once over 12 months of surveys (M age = 33.79; 70.1% White), reflecting on their current therapy experiences. Through thematic analysis of qualitative data, the following themes were constructed regarding discussing sociopolitical events: (a) facilitating coping via bearing witness to clients’ internal experiences and implementing other therapeutic interventions; (b) moving beyond the individual by integrating identity, systems, or contexts; (c) feeling disconnected and misunderstood. We grouped participants’ helpful experiences into the following themes: (1) availability, connection, and therapeutic approaches facilitate positive experiences; (2) the necessity of knowledge, education, and affirmation of TGD identities; (3) helpful therapy means seeing the world in which clients live. We grouped participants’ unhelpful experiences into the following themes: (1) logistical issues can interfere with therapy; (2) lack of depth and disconnection results in subpar therapy; (3) insufficient understandings of TGD identities results in potentially harmful practices. These findings deepen understandings of how to integrate discussions about current events into therapy and provide competent and affirming care to TGD clients
Automatic differentiation of u- and n-serrated patterns in direct immunofluorescence images
Epidermolysis bullosa acquisita (EBA) is a subepidermal autoimmune blistering disease of the skin. Manual u- and n-serrated patterns analysis in direct immunofluorescence (DIF) images is used in medical practice to differentiate EBA from other forms of pemphigoid. The manual analysis of serration patterns in DIF images is very challenging, mainly due to noise and lack of training of the immunofluorescence (IF) microscopists. There are no automatic techniques to distinguish these two types of serration patterns. We propose an algorithm for the automatic recognition of such a disease. We first locate a region where u- and n-serrated patterns are typically found. Then, we apply a bank of B-COSFIRE filters to the identified region of interest in the DIF image in order to detect ridge contours. This is followed by the construction of a normalized histogram of orientations. Finally, we classify an image by using the nearest neighbors algorithm that compares its normalized histogram of orientations with all the images in the dataset. The best results that we achieve on the UMCG publicly available data set is 84.6% correct classification, which is comparable to the results of medical experts
Spatial distribution of wood volume in brazilian savannas
Here we model and describe the wood volume of Cerrado Sensu Stricto, a highly heterogeneous vegetation type in the Savanna biome, in the state of Minas Gerais, Brazil, integrating forest inventory data with spatial-environmental variables, multivariate regression, and regression kriging. Our study contributes to a better understanding of the factors that affect the spatial distribution of the wood volume of this vegetation type as well as allowing better representation of the spatial heterogeneity of this biome. Wood volume estimates were obtained through regression models using different environmental variables as independent variables. Using the best fitted model, spatial analysis of the residuals was carried out by selecting a semivariogram model for generating an ordinary kriging map, which in turn was used with the fitted regression model in the regression kriging technique. Seasonality of both temperature and precipitation, along with the density of deforestation, explained the variations of wood volume throughout Minas Gerais. The spatial distribution of predicted wood volume of Cerrado Sensu Stricto in Minas Gerais revealed the high variability of this variable (15.32 to 98.38 m3 ha-1) and the decreasing gradient in the southeast-northwest direction914COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESSem informaçã
The Rapidly Flaring Afterglow of the Very Bright and Energetic GRB 070125
We report on multi-wavelength observations, ranging from the X-ray to radio
wave bands, of the IPN-localized gamma-ray burst GRB 070125. Spectroscopic
observations reveal the presence of absorption lines due to O I, Si II, and C
IV, implying a likely redshift of z = 1.547. The well-sampled light curves, in
particular from 0.5 to 4 days after the burst, suggest a jet break at 3.7 days,
corresponding to a jet opening angle of ~7.0 degrees, and implying an intrinsic
GRB energy in the 1 - 10,000 keV band of around E = (6.3 - 6.9)x 10^(51) erg
(based on the fluences measured by the gamma-ray detectors of the IPN network).
GRB 070125 is among the brightest afterglows observed to date. The spectral
energy distribution implies a host extinction of Av < 0.9 mag. Two
rebrightening episodes are observed, one with excellent time coverage, showing
an increase in flux of 56% in ~8000 seconds. The evolution of the afterglow
light curve is achromatic at all times. Late-time observations of the afterglow
do not show evidence for emission from an underlying host galaxy or supernova.
Any host galaxy would be subluminous, consistent with current GRB host-galaxy
samples. Evidence for strong Mg II absorption features is not found, which is
perhaps surprising in view of the relatively high redshift of this burst and
the high likelihood for such features along GRB-selected lines of sight.Comment: 50 pages, 9 figures, 5 tables Accepted to the Astrophysical Journa
Curva de calibração para predição do teor de óleo pela análise do espectrômetro de infravermelho próximo (NIR) em ensaios de competição de cultivares de girassol no Brasil.
O objetivo deste trabalho foi estabelecer uma curva de calibração para avaliação do teor de óleo pelo NIR em de ensaios de competição de cultivares de girassol no Brasil. Os dados foram obtidos de genótipos avaliados em ensaios de competição de cultivares, em delineamento de blocos completos ao acaso, conduzidos na safra 2007/2008 e 2008. Para a determinação da curva de calibração foram utilizados 683 valores, estimados pela Ressonância Magnética Nuclear (RMN), a uma faixa de 23,47 a 55,34% de óleo. Os espectros foram coletados de sementes intactas por esfera de integração em um NIR Thermo Scientific modelo Antaris II. Foi utilizado o sinal spectrum sem derivada, sendo que cada espectro foi uma média de 32 scans com resolução 4 cm-1. A região estabelecida para a curva de calibração foi de 7.576 a 5.680 cm-1. Para avaliar a precisão da curva foi calculado o coeficiente de determinação (R2) e o erro padrão de calibração (SEC) entre os dados obtidos pelo RMN e NIR. Para validação da curva foram calculadas correlações de Pearson entre valores estimados no NIR e RMN, obtidos de ensaios conduzidos na safra 2008, utilizando-se cada valor observado, as médias dos genótipos em cada local e a média geral dos genótipos nestes ensaios. Os locais usados para calibração da curva foram diferentes daqueles para sua validação. A curva de calibração apresentou um coeficiente de determinação (R2) de 0,88, erro padrão de calibração (SEC) de 1,76 e margem de erro variando de -5 a 6%. A correlação entre médias gerais dos genótipos nos ensaios foi de 0,82 e a correlação entre média dos genótipos em cada local foi de 0,71, indicando que a curva de calibração estabelecida no NIR é satisfatória para a avaliação do teor de óleo de genótipos de girassol em ensaio de competição de cultivares no Brasil
Serovar-dependent differences in Hfq-regulated phenotypes in actinobacillus pleuropneumoniae
The RNA chaperone Hfq regulates diverse processes in numerous bacteria. In this study, we compared phenotypes (growth rate, adherence, response to different stress conditions, and virulence in Galleria mellonella) of wild-type (WT) and isogenic hfq mutants of three serovars (1, 8 and 15) of the porcine pathogen A. pleuropneumoniae. Similar growth in rich broth was seen for all strains except Ap1∆hfq, which showed slightly reduced growth throughout the 24 hour time course, and the complemented Ap8∆hfqC mutant had a prolonged lag phase. Differences were seen between the three serovar WT strains regarding adherence, stress response and virulence in G. mellonella, and deletion of hfq affected some, but not all of these phenotypes, depending on serovar. Complementation by expression of cloned hfq from an endogenous promoter only restored some WT phenotypes, indicating that complex regulatory networks may be involved, and that levels of Hfq may be as important as presence/absence of the protein regarding its contribution to gene regulation. Our results support that Hfq is a pleiotropic global regulator in A. pleuropneumoniae, but serovar-related differences exist. These results highlight the importance of testing multiple strains/serovars within a given species when determining contributions of global regulators, such as Hfq, to expression of complex phenotypes
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