1,520 research outputs found
MECANISMOS DE REGENERAÇÃO NATURAL EM ÁREA INCENDIADA EM UMA FLORESTA OMBRÓFILA DENSA MONTANA, ESPÍRITO SANTO, BRASIL
As mudanças climáticas e a fragmentação de ecossistemas estão aumentando a freqüência e a intensidade dos incêndios nas florestas tropicais úmidas. Avaliar como a floresta se recupera após os incêndios é importante para entender as mudanças na composição, estrutura e da funcionalidade da comunidade, aspectos de fundamental importância para a restauração de áreas degradadas. Nosso objetivo foi avaliar a importância relativa da germinação do banco de sementes do solo, da sobrevivência das plântulas regenerantes e indívuos adultos, e do rebrotamento vegetativo, como um possível atributo funcional de persistência de espécies pós-fogo, em um fragmento de floresta ombrófila densa montana (Serra do Valentim, Iúna, Espírito Santo, Brasil) incendiado em 2014. O levantamento foi realizado em 30 parcelas (5x10m, 2 ecossistemas de referência e 1 área incendiada, 10 parcelas cada), contando e classificando todos os indívuos em: sobreviventes, regenerantes, rebrotadores (rebrota de raiz, base e caule) e indíviduos emergidos no banco de sementes do solo. Após a compreensão da estrutura da comunidade amostrada, realizamos análises de ordenação (PcoA e LDA), para entender de que forma as espécies estão distribuídas entre as áreas em cada mecanismo, e qual mecanismo tem maior peso para a regeneração natural das áreas. Selecionamos também as espécies que representaram 80% da dominância da de toda comunidade e coletamos os atributos funcionais relacionados à persistência, sobrevivência e dispersão. Com uma matriz CWM e de espécies × atributos realizamos outra análise PCoA, para entender como os atributos estão distribuídos entre as espécies e como eles se relacionam com o desempenho em cada uma das áreas. Nossos resultamos mostraram que o rebrotamento vegetatitvo pode ser um mecanismo e um atributo funcional de fundamental importância para a regenereção natural e a resiliência da comunidade após a o fogo, garantindo a persistência e a sobrevivência de algumas espécies. Porém outros mecanismos, como o banco de sementes do solo, contribui com espécies pioneiras, fundamentais para a recomposição da área
Infection with Chlamydia Pneumoniae Alters Calcium-associated Gene Regulation and Processes in Neuronal Cells and Monocytes: Implications for Alzheimer’s Disease
Background: First proposed by Khachaturian in 1994, the calcium hypothesis postulates that sustained disturbance of intracellular calcium is the leading cause of neurodegenerative disorders. Studies showing alteration in calcium signaling in both sporadic and familial Alzheimer’s disease (AD) support this hypothesis. Intracellular calcium signaling is tightly regulated in time, intensity, and space, and is responsible for a variety of neuronal functions. Calcium influx from the extracellular environment modulates calcium levels, as do intracellular stores in the endoplasmic reticulum. The focus of this study was to test various calcium related genes in both monocytes and neuronal cells. Previous studies have shown that cells infected with Chlamydia pneumoniae (Cpn) exhibit altered protein processing, such as amyloid and tau modification, consistent with those found in AD. We expect to see significant alterations in calcium genes, as well as their protein products in Cpn infected cells. Every calcium gene has a unique function in the cell. Determining which genes are up or down regulated following infection may provide insight into how the neurodegeneration process observed in AD is initiated by Cpn infections
Optimal tumor sampling for immunostaining of biomarkers in breast carcinoma
IntroductionBiomarkers, such as Estrogen Receptor, are used to determine therapy and prognosis in breast carcinoma. Immunostaining assays of biomarker expression have a high rate of inaccuracy; for example, estimates are as high as 20% for Estrogen Receptor. Biomarkers have been shown to be heterogeneously expressed in breast tumors and this heterogeneity may contribute to the inaccuracy of immunostaining assays. Currently, no evidence-based standards exist for the amount of tumor that must be sampled in order to correct for biomarker heterogeneity. The aim of this study was to determine the optimal number of 20X fields that are necessary to estimate a representative measurement of expression in a whole tissue section for selected biomarkers: ER, HER-2, AKT, ERK, S6K1, GAPDH, Cytokeratin, and MAP-Tau.MethodsTwo collections of whole tissue sections of breast carcinoma were immunostained for biomarkers. Expression was quantified using the Automated Quantitative Analysis (AQUA) method of quantitative immunofluorescence. Simulated sampling of various numbers of fields (ranging from one to thirty five) was performed for each marker. The optimal number was selected for each marker via resampling techniques and minimization of prediction error over an independent test set.ResultsThe optimal number of 20X fields varied by biomarker, ranging between three to fourteen fields. More heterogeneous markers, such as MAP-Tau protein, required a larger sample of 20X fields to produce representative measurement.ConclusionsThe optimal number of 20X fields that must be sampled to produce a representative measurement of biomarker expression varies by marker with more heterogeneous markers requiring a larger number. The clinical implication of these findings is that breast biopsies consisting of a small number of fields may be inadequate to represent whole tumor biomarker expression for many markers. Additionally, for biomarkers newly introduced into clinical use, especially if therapeutic response is dictated by level of expression, the optimal size of tissue sample must be determined on a marker-by-marker basis
CGIAR modeling approaches for resource-constrained scenarios: I. Accelerating crop breeding for a changing climate.
Crop improvement efforts aiming at increasing crop production (quantity, quality) and adapting to climate change have been subject of active research over the past years. But, the question remains 'to what extent can breeding gains be achieved under a changing climate, at a pace sufficient to usefully contribute to climate adaptation, mitigation and food security?'. Here, we address this question by critically reviewing how model-based approaches can be used to assist breeding activities, with particular focus on all CGIAR (formerly the Consultative Group on International Agricultural Research but now known simply as CGIAR) breeding programs. Crop modeling can underpin breeding efforts in many different ways, including assessing genotypic adaptability and stability, characterizing and identifying target breeding environments, identifying tradeoffs among traits for such environments, and making predictions of the likely breeding value of the genotypes. Crop modeling science within the CGIAR has contributed to all of these. However, much progress remains to be done if modeling is to effectively contribute to more targeted and impactful breeding programs under changing climates. In a period in which CGIAR breeding programs are undergoing a major modernization process, crop modelers will need to be part of crop improvement teams, with a common understanding of breeding pipelines and model capabilities and limitations, and common data standards and protocols, to ensure they follow and deliver according to clearly defined breeding products. This will, in turn, enable more rapid and better-targeted crop modeling activities, thus directly contributing to accelerated and more impactful breeding efforts.Online Version of Record before inclusion in an issue
Daily variation of zooplankton abundance and evenness in the Rosana reservoir, Brazil: biotic and abiotic inferences
Evidence of contamination by oil and oil products in the Santos-Sao Vicente estuary, Sao Paulo, Brazil
Different components of the mixed function oxidase (MFO) system and the levels of fluorescent aromatic compounds in bile (FACs) were measured in Cathorops spixii in order to assess the impact of polycyclic aromatic hydrocarbons (PAHs). Fish were sampled in an estuary (Santos/Sao Vicente) with a history of contamination by PAHs, mainly due to the presence of the industrial complex of Cubatao city and of another of low anthropogenic influence (Cananeia) on the Brazilian coast. FACs were higher in fish from the polluted site, and the PAH 5 and 6-ring metabolites were the most frequent - with 14% and 15%, respectively. Levels of the different components of the MFO system showed the same variation profile as the FACs for both estuaries. Therefore, the values found for somatic indexes and biomarkers with data of bile PAH metabolites indicate the presence of organic contaminants, especially in the area subject to the influence of the industrial complex on the Santos/Sao Vicente estuary.CAPES (Brazilian Agency for Science and Technology); Oceanographic Institute of Sao Paulo University; Laboratory of Ecotoxicology and Environmental Chemistry of the University of Algarve; CAPES-PDEE [BEX 2176/07-6]info:eu-repo/semantics/publishedVersio
First radial velocity results from the MINiature Exoplanet Radial Velocity Array (MINERVA)
The MINiature Exoplanet Radial Velocity Array (MINERVA) is a dedicated
observatory of four 0.7m robotic telescopes fiber-fed to a KiwiSpec
spectrograph. The MINERVA mission is to discover super-Earths in the habitable
zones of nearby stars. This can be accomplished with MINERVA's unique
combination of high precision and high cadence over long time periods. In this
work, we detail changes to the MINERVA facility that have occurred since our
previous paper. We then describe MINERVA's robotic control software, the
process by which we perform 1D spectral extraction, and our forward modeling
Doppler pipeline. In the process of improving our forward modeling procedure,
we found that our spectrograph's intrinsic instrumental profile is stable for
at least nine months. Because of that, we characterized our instrumental
profile with a time-independent, cubic spline function based on the profile in
the cross dispersion direction, with which we achieved a radial velocity
precision similar to using a conventional "sum-of-Gaussians" instrumental
profile: 1.8 m s over 1.5 months on the RV standard star HD 122064.
Therefore, we conclude that the instrumental profile need not be perfectly
accurate as long as it is stable. In addition, we observed 51 Peg and our
results are consistent with the literature, confirming our spectrograph and
Doppler pipeline are producing accurate and precise radial velocities.Comment: 22 pages, 9 figures, submitted to PASP, Peer-Reviewed and Accepte
Tuberous sclerosis with pulmonary lymphangioleiomyomatosis and renal angiomyolipomas. Computed tomographic findings: a case report
The authors describe a case of a 31-year-old female with tuberous sclerosis, a genetic, rare, variably expressed disease. Clinical symptoms were chest pain, and progressive dyspnea. Computed tomography scan of the chest showed bilateral, diffuse, small thin-walled cysts scattered throughout the lungs characteristic for pulmonary lymphangioleiomyomatosis. Computed tomography scan of the abdomen revealed enlarged, heterogeneous kidneys, with low density tumors corresponding to angiomyolipomas. Pulmonary lymphangioleiomyomatosis and bilateral renal angiomyolipomas are some presentations of tuberous sclerosis and the coexistence of both conditions may cause devastating morbidity and mortality
Analogues of Marine Guanidine Alkaloids Are in Vitro Effective against Trypanosoma cruzi and Selectively Eliminate Leishmania (L.) infantum Intracellular Amastigotes
Synthetic analogues of marine sponge guanidine alkaloids showed in vitro antiparasitic activity against Leishmania (L.) infantum and Trypanosoma cruzi. Guanidines 10 and 11 presented the highest selectivity index when tested against Leishmania. The antiparasitic activity of 10 and 11 was investigated in host cells and in parasites. Both compounds induced depolarization of mitochondrial membrane potential, upregulation of reactive oxygen species levels, and increased plasma membrane permeability in Leishmania parasites. Immunomodulatory assays suggested an NO-independent effect of guanidines 10 and 11 on macrophages. The same compounds also promoted anti-inflammatory activity in L. (L.) infantum-infected macrophages cocultived with splenocytes, reducing the production of cytokines MCP-1 and IFN-γ. Guanidines 10 and 11 affect the bioenergetic metabolism of Leishmania, with selective elimination of parasites via a host-independent mechanism
- …