4,167 research outputs found
Terrestrial mammal responses to habitat structure and quality of remnant riparian forests in an Amazonian cattle-ranching landscape
Extensive 1970–2010 deforestation in the Brazilian Amazon has generated a ~ 1.5 Mha fragmented region known as the ‘arc of deforestation’. Farmers and cattle ranchers throughout Brazil are legally required to set-aside riparian forest strips within their landholdings, but recent legislative changes have relaxed the minimum mandatory conditions of these riparian forests. In this context, we assessed the functional role of riparian forest remnants as landscape connectors for medium to large-bodied terrestrial mammals in a vast fragmented landscape of southern Amazonia. We selected 38 riparian forest strips and five riparian sites within continuous forest, installed four to five camera-traps along each riparian zone (199 camera-trap stations), and sampled the terrestrial mammal assemblage for 60 days per station during the dry seasons of 2013 and 2014. We compared mammal use of riparian forests within both continuous and highly fragmented forests, and examined the effects of corridor width, corridor habitat structure, and landscape context on mammal species richness, composition, and functional diversity, all of which were higher in continuous forests than in riparian remnants. Functional diversity differences between corridor type was trait-independent and mediated by differences in species richness. Forest habitat degradation was associated with overall lower species richness, whereas forest specialists were more species-rich in increasingly wider corridors. Compositional shifts indicate that deforestation and forest degradation favours matrix-tolerant species with lower levels of forest habitat specificity. We show the potential landscape connectivity role for forest mammals of riparian corridors, whose width and forest degradation status are key predictors of community-wide responses. We provide evidence on the importance of these relict riparian strips to forest vertebrates, strengthening the scientific arguments that help justify the recently embattled legal requirements to maintain effective riparian corridors in Brazil
Comparison of dynamic isotope power systems for distributed planet surface applications
Dynamic isotope power system (DIPS) alternatives were investigated and characterized for the surface mission elements associated with a lunar base and subsequent manned Mars expedition. System designs based on two convertor types were studied. These systems were characterized parametrically and compared over the steady-state electrical output power range 0.2 to 20 kWe. Three methods of thermally integrating the heat source and the Stirling heater head were considered, depending on unit size. Figures of merit were derived from the characterizations and compared over the parametric range. Design impacts of mission environmental factors are discussed and quantitatively assessed
Closing the Neutrino "BSM Gap": Physics Potential of Atmospheric Through-Going Muons at DUNE
Many Beyond-Standard Model physics signatures are enhanced in high-energy
neutrino interactions. To explore these signatures, ultra-large Cherenkov
detectors such as IceCube exploit event samples with charged current muon
neutrino interactions > 1 TeV. Most of these interactions occur below the
detector volume, and produce muons that enter the detector. However, the large
spacing between detectors leads to inefficiency for measuring muons with
energies below or near the critical energy of 400 GeV. In response, IceCube has
built a densely instrumented region within the larger detector. This provides
large samples of well-reconstructed interactions that are contained within the
densely instrumented region, extending up to energies of ~50 GeV. This leaves a
gap of relatively unexplored atmospheric-neutrino events with energies between
50 GeV and 1 TeV in the ultra-large detectors. In this paper we point out that
interesting Beyond Standard Model signatures may appear in this energy window,
and that early running of the DUNE far detectors can give insight into new
physics that may appear in this range.Comment: 10 pages, 9 figures, 1 tabl
In Memoriam for the Recently Departed: Lupe Ontiveros, Tony Curiel, Juan Antonio Castro, Elizabeth Peña, Goyo Flores, and Lina Gallego
In Memoriam for the Recently Departed: Lupe Ontiveros, Tony Curiel, Juan Antonio Castro, Elizabeth Peña, Goyo Flores, and Lina Gallego
Developmental Expression of IL-2-Receptor Light Chain (CD25) in the Chicken Embryo
Thymocyte differentiation obeys the same fundamental principles in mammals as in avian
species. This parallelism does not only affect the developmentally controlled acquisition of
CD3, 4, 8, and TcR isotype expression, but also concerns CD25, the light chain of the interleukin-2 receptor (IL-2R). On chicken thymocytes, surface CD25, which is recognized by the
monoclonal antibody INN Ch16, is first observed during day 11 of embryonic life, and peaks
at day 14, when it is expressed by about one-third of all lymphoid cells. CD25 is found on
subsets of all ,thymocyte populations as defined by TcRαβ, TcRγδ, 2, CD4, and CD8 expression,
cortical or medullary localization, and is also present on a subset of intrathymic nurse-cell
lymphocytes. These findings suggest phylogenetic conservation of the IL-2/IL-2R-triggered
differentiation pathway previously described for mammalian species, thus under-lining
its probable functional importance
Spatiotemporal Distribution Of Different Extracellular Polymeric Substances And Filamentation Mediate Xylella Fastidiosa Adhesion And Biofilm Formation
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento CientÃfico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento CientÃfico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de NÃvel Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento CientÃfico e Tecnológico (CNPq)Microorganism pathogenicity strongly relies on the generation of multicellular assemblies, called biofilms. Understanding their organization can unveil vulnerabilities leading to potential treatments; spatially and temporally-resolved comprehensive experimental characterization can provide new details of biofilm formation, and possibly new targets for disease control. Here, biofilm formation of economically important phytopathogen Xylella fastidiosa was analyzed at single-cell resolution using nanometer-resolution spectro-microscopy techniques, addressing the role of different types of extracellular polymeric substances (EPS) at each stage of the entire bacterial life cycle. Single cell adhesion is caused by unspecific electrostatic interactions through proteins at the cell polar region, where EPS accumulation is required for more firmly-attached, irreversibly adhered cells. Subsequently, bacteria form clusters, which are embedded in secreted loosely-bound EPS, and bridged by up to ten-fold elongated cells that form the biofilm framework. During biofilm maturation, soluble EPS forms a filamentous matrix that facilitates cell adhesion and provides mechanical support, while the biofilm keeps anchored by few cells. This floating architecture maximizes nutrient distribution while allowing detachment upon larger shear stresses; it thus complies with biological requirements of the bacteria life cycle. Using new approaches, our findings provide insights regarding different aspects of the adhesion process of X. fastidiosa and biofilm formation.5Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento CientÃfico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento CientÃfico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de NÃvel Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento CientÃfico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento CientÃfico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento CientÃfico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de NÃvel Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento CientÃfico e Tecnológico (CNPq)FAPESP [2010/51748-7, 2010/18107-8, 2010/50712-9]CNPq [479486/2012-3]CNPq [573913/2008-0]FAPESP [08/57906-3
Particle size and lime addiction on properties of wood-cement composites produced by the method of densification by vibro compaction
This paper aimed to evaluate the effects of particle size and the use of lime as a pretreatment of Pinus spp wood particles on the production of wood-cement composites by vibro-compaction densification. Specimens for internal bond and static bending were produced with two different particle sizes: G1, particles that pass through a 4mm screen and were retained at 2mm screen, and G2, particles that pass through a 2mm screen and were retained at 0.84mm screen. The use of lime was also tested in two different methods as pretreatment of wood particles: carbonatation of wood particles before being used in the composite mixture; and addition of hydrated lime directly to the composite mixture. Use of larger particles (G1) presented higher values of internal bond and MOR than composites produced with smaller particles (G2). About the pretreatments, the use of hydrated lime resulted in composites with higher density and better internal bond
A doença de Chagas como um modelo mecanicista para testar uma nova hipótese
The association between depression and cardiovascular disease is well documented. Nevertheless, the process through which they are linked remains unknown, as does the direction of this relationship. Studies have suggested both that depression is a risk factor for heart disease and that heart disease is a risk factor for depression. A number of studies have established that a relationship exists between depression and inflammation, with alterations in the levels of inflammatory markers (IL-1, IL-6, TNF-alpha and others). Depressive symptoms have also been identified in many diseases characterized by inflammatory processes e.g. rheumatoid arthritis, bronchial asthma, diabetes, tuberculosis and cardiovascular diseases. In this brief viewpoint, we explain and propose how to use Chagas disease, a disorder characterized by inflammatory processes and leading to cardiovascular and autonomic problems, as a model for studying the directionality of the relationship between heart disease and depression.A associação entre depressão e doença cardiovascular está bem documentada. Não obstante, o processo pelo qual está associada permanece desconhecido, assim como o sentido desta associação. Estudos têm sugerido que tanto a depressão é um fator de risco para a doença cardiovascular quanto esta o é para a depressão. Uma série de trabalhos tem estabelecido que uma relação existe entre depressão e inflamação, com alterações evidenciadas por marcadores de inflamação (IL-1, IL-6, TNF alfa e outros). Sintomas de depressão também têm sido identificados em diversas doenças caracterizadas por processos inflamatórios, tais como artrite reumatoide, asma brônquica, diabete, tuberculose e doenças cardiovasculares. Nesta breve opinião é explicitado e proposto como empregar a doença de Chagas, um agravo caracterizado por processos inflamatórios e indutor de problemas cardiovasculares e autonômicos, como um modelo de estudo da direcionalidade da relação entre doença cardÃaca e depressão
Anthropogenic drivers of headwater and riparian forest loss and degradation in a highly fragmented southern Amazonian landscape
Freshwater ecosystems across the Amazon are largely comprised of small streams and headwaters of riparian zones. These areas are legally protected within private landholdings in Brazil, but recent changes in the environmental legislation have slackened protection requirements, with unpredictable consequences to the integrity and functioning of these freshwater environments. Local drivers of riparian forest loss and degradation should be understood by considering context-dependent land management practices and pressures within a region. Here, we examine the spatial determinants of the total amount and spectral quality of both headwater and overall riparian forests within private landholdings within a highly fragmented region of southern Amazonia. We built generalized linear models to assess how the amount and spectral quality of headwater and riparian forests respond to landholding size and distance to roads and an urban center, and document landholder compliance rates according to both the current and previous Brazilian environmental legislation. Although forest loss and degradation are typically associated, forest degradation responded independently to the same drivers. Headwater forests were generally more degraded than riparian forests, and smallholders complied less often with legal requirements than largeholders. Proximity to roads and the nearest town had a detrimental effect on both headwater and riparian forest amount and quality, and distance to the nearest town affected all variables, except for headwater forest quality. Compliance with environmental legislation is the first step in protecting riparian and headwater forests, but alternative landscape management strategies must be explored, particularly focusing on smallholdings, which are most vulnerable to deforestation and forest degradation
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