Cobertura do solo e estabilidade de agregados em Latossolo Amarelo dos Tabuleiros Costeiros no Nordeste do Brasil.

O trabalho foi realizado de março/2008 a julho/2010, na área da Embrapa Mandioca e Fruticultura, em Cruz das Almas (BA), a 12°40?19? de latitude Sul e 39°06?22? de longitude Oeste Gr., altitude de 220 metros, com médias anuais de pluviosidade com 1.200 mm, temperatura 24ºC e a umidade relativa do ar 80%. O levantamento dos solos da Embrapa Mandioca e Fruticultura permitiu identificar as classes de solos, declive das áreas e localização dos recursos hídricos. Localizaram-se áreas com declive maior que 12 %, próximas a açudes ou mananciais, que estavam com cobertura vegetal inadequada ou sem cobertura. A cobertura vegetal, a granulometria e a estabilidade da estrutura do solo são fatores fundamentais no controle da erosão. Com o objetivo de avaliar a influência da cobertura vegetal na estabilidade dos agregados do solo, foi avaliado um Latossolo Amarelo distrófico (LAd4), em uma área sob pastagem e em outra sob mata, ambas em uma encosta com declive de 8 % a 12 %, próximas as fontes que abastecem os laboratórios da Embrapa Mandioca e Fruticultura.PDF. 070

Prolonging disuse in aged mice amplifies cortical but not trabecular bones’ response to mechanical loading

Objective: Short-term neurectomy-induced disuse (SN) has been shown to restore load responses in aged mice. We examined whether this restoration was further enhanced in both cortical and trabecular bone by simply extending the SN. Methods: Following load: strain calibration, tibiae in female C57BL/J6 mice at 8, 14 and 20 weeks and 18 months (n=8/group) were loaded and bone changes measured. Effects of long-term SN examined in twenty-six 18 months-old mice, neurectomised for 5 or 100 days with/without subsequent loading. Cortical and trabecular responses were measured histomorphometrically or by micro-computed tomography. Results: Loading increased new cortical bone formation, elevating cross-sectional area in 8, 14 and 20 week-old (p <0.05), but not 18 month-old aged mice. Histomorphometry showed that short-term SN reinstated load-responses in aged mice, with significant 33% and 117% increases in bone accrual at 47% and 37%, but not 27% of tibia length. Cortical responses to loading was heightened and widespread, now evident at all locations, following prolonged SN (108, 167 and 98% at 47, 37 and 27% of tibial length, respectively). In contrast, loading failed to modify trabecular bone mass or architecture. Conclusions: Mechanoadaptation become deficient with ageing and prolonging disuse amplifies this response in cortical but not trabecular bone

Alterações nas propriedades físicas de um Latossolo Amarelo Distrocoeso em função da aplicação de carvão vegetal.

A necessidade de adequação dos sistemas de produção agrícola tem estimulado a busca de novos manejos do solo. A evolução tem procurado uma maior capacidade para diminuir a emissão e aumentar a conversão do carbono do solo

Experimental Determination of Thermal Entanglement in Spin Clusters using Magnetic Susceptibility Measurements

The present work reports an experimental observation of thermal entanglement in a clusterized spin chain formed in the compound Na$_2$Cu$_5$Si$_4$O$_{14}$. The presence of entanglement was investigated through two measured quantities, an Entanglement Witness and the Entanglement of Formation, both derived from the magnetic susceptibility. It was found that pairwise entanglement exists below $\sim 200$ K. Tripartite entanglement was also observed below $\sim 240$ K. A theoretical study of entanglement evolution as a function of applied field and temperature is also presented.Comment: Submited to Phys. Rev.

Components of multifractality in the Central England Temperature anomaly series

We study the multifractal nature of the Central England Temperature (CET) anomaly, a time series that spans more than 200 years. The series is analyzed as a complete data set and considering a sliding window of 11 years. In both cases, we quantify the broadness of the multifractal spectrum as well as its components defined by the deviations from the Gaussian distribution and the influence of the dependence between measurements. The results show that the chief contribution to the multifractal structure comes from the dynamical dependencies, mainly the weak ones, followed by a residual contribution of the deviations from Gaussianity. However, using the sliding window, we verify that the spikes in the non-Gaussian contribution occur at very close dates associated with climate changes determined in previous works by component analysis methods. Moreover, the strong non-Gaussian contribution found in the multifractal measures from the 1960s onwards is in agreement with global results very recently proposed in the literature.Comment: 21 pages, 10 figure

Dark Sector from Interacting Canonical and Non-Canonical Scalar Fields

In this work it is investigated general models with interactions between two canonical scalar fields and between one non-canonical (tachyon-type) and one canonical scalar field. The potentials and couplings to the gravity are selected through the Noether symmetry approach. These general models are employed to describe interactions between dark energy and dark matter, with the fields being constrained by the astronomical data. The cosmological solutions of some cases are compared with the observed evolution of the late Universe.Comment: 20 pages, 13 figures, correction of misprints in eqs. (4), (5), (43), (44