985 resultados para Henirich, Bernd


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Includes bibliography

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We report on the realization of a capacitive dilatometer, designed for high-resolution measurements of length changes of a material for temperatures 1.4K ≤ T ≤ 300K and hydrostatic pressure P ≤ 250MPa. Helium ( 4He) is used as a pressure-transmitting medium, ensuring hydrostatic-pressure conditions. Special emphasis has been given to guarantee, to a good approximation, constant-pressure conditions during temperature sweeps. The performance of the dilatometer is demonstrated by measurements of the coefficient of thermal expansion at pressures P ≃ 0.1MPa (ambient pressure) and 104MPa on a single crystal of azurite, Cu 3(CO 3) 2(OH) 2, a quasi-one-dimensional spin S = 1/2 Heisenberg antiferromagnet. The results indicate a strong effect of pressure on the magnetic interactions in this system. © 2012 American Institute of Physics.

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Contiene programas de la DSE sobre el hábitat en América Latina y un apéndice con los eventos realizados por la Fundación en favor del tercer sector.

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Incluye Bibliografía

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Este trabalho realiza uma leitura da obra Três Casas e um rio de Dalcídio Jurandir, seguindo alguns percursos para a formação da identidade de Alfredo. Preocupa-nos, primeiramente, verificar como a identidade de Alfredo se articula diante das diferenças culturais e dicotomias como popular/erudito; oral/escrito. Popular e oral, ligados a valores da mãe negra, D.Amélia, e erudito e escrito, relacionado ao pai, Major Alberto. Em seguida, apresenta os traços fronteiriços auxiliadores da elaboração da identidade de Alfredo, Finalmente, verifica-se como as narrativas presentes na obra estão incorporadas no texto dalcidiano, e sua importância para a resolução de alguns conflitos vivenciados pelo protagonista.E para que se possa visualizar a abordagens teóricas aqui trabalhadas, contribuem com este estudo autores como Stuart Hall, D. Shüller, Zilá Bernd e, ainda, serão citados Walter Benjamin, Anthony Giddens, entre outros.

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We present results of ultrasonic measurements on a single crystal of the distorted diamond-chain compound azurite Cu-3(CO3)(2)(OH)(2). Pronounced elastic anomalies are observed in the temperature dependence of the longitudinal elastic mode c(22) which can be assigned to the relevant magnetic interactions in the system and their couplings to the lattice degrees of freedom. From a semiquantitative analysis of the magnetic contribution to c(22) the magnetoelastic coupling G = partial derivative J(2)/partial derivative epsilon(b) can be estimated, where J(2) is the intradimer coupling constant and epsilon(b) the strain along the intrachain b axis. We find an exceptionally large coupling constant of | G| similar to 3650 K highlighting an extraordinarily strong sensitivity of J(2) against changes of the b-axis lattice parameter. These results are complemented by measurements of the hydrostatic pressure dependence of J2 by means of thermal expansion and magnetic susceptibility measurements performed both at ambient and finite hydrostatic pressure. We propose that a structural peculiarity of this compound, in which Cu2O6 dimer units are incorporated in an unusually stretched manner, is responsible for the anomalously large magnetoelastic coupling.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Although many studies have shown that soil solution chemistry can be a reliable indicator of biogeochemical cycling in forest ecosystems, the effects of litter manipulations on the fluxes of dissolved elements in gravitational soil solutions have rarely been investigated. We estimated the fluxes of NH4-N, NO3-N, K, Ca, Mg, Na, Cl, dissolved organic nitrogen (DON) and dissolved organic carbon (DOC) over the first two years after re-planting Eucalyptus trees in the coastal area of Congo. Two treatments were replicated in two blocks after clear-cutting 7-year-old stands: in treatment R, all the litter above the mineral soil was removed before planting, and in a double slash (DS) treatment, the amount of harvest residues was doubled. The soil solutions were sampled down to a depth of 4 m and the water fluxes were estimated using the Hydrus 1D model parameterized from soil moisture measurements in 4 plots. Isotopic and spectroscopic analytical techniques were used to assess the changes in dissolved organic matter (DOM) properties throughout the transfer in the soil. The first year after planting, the fluxes of NH4-N, K, Ca, Mg, Na, Cl and DOC in the topsoil of the DS treatment were 2-5 times higher than in R, which showed that litter was a major source of dissolved nutrients. Nutrient fluxes in gravitational solutions decreased sharply in the second year after planting, irrespective of the soil depth, as a result of intense nutrient uptake by Eucalyptus trees. Losses of dissolved nutrients were noticeably low in these Eucalyptus plantations despite a low cation exchange capacity, a coarse soil texture and large amounts of harvest residues left on-site at the clear cut in the DS treatment. All together, these results clarified the strong effect of litter manipulation observed on eucalypt growth in Congolese sandy soils. DOM fluxes, as well as changes in delta C-13, C:N and aromaticity of DOM throughout the soil profile showed that the organic compounds produced in the litter layer were mainly consumed by microorganisms or retained in the topsoil. Below a depth of 15 cm, most of the DOC and the DON originated from the first 2 cm of the soil and the exchanges between soil solutions and soil organic matter were low. (C) 2014 Elsevier B.V. All rights reserved.

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The annual return, seasonal occurrence, and site fidelity of Korean-Okhotsk or western gray whales on their feeding grounds off northeastern Sakhalin Island, Russia, were assessed by boat-based photo-identification studies in 1994-1998. A total of 262 pods were observed, ranging in size from 1 to 9 whales with an overall mean of 2.0'. Sixty-nine whales were individually identified, and a majority of all whales (71.0%) were observed in multiple years. Annual sighting frequencies ranged from 1 to 18 d, with a mean of 5.4 d. The percentage of whales re-identified from previous years showed a continuous annual increase, reaching 87.0% by the end of the study. Time between first and last sighting of identified individuals within a given year was 1-85 d, with an overall mean of 40.6 d. Annual calf proportions ranged from 4.3% (1997) to 13.2% (1998), and mother-calf separations generally occurred between July and September. The seasonal site fidelity and annual return of whales to this part of the Okhotsk Sea emphasize its importance as a primary feeding ground for this endangered population.

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Gray whales (Eschrichtius robustus) occur along the eastern and western coastlines of the North Pacific as two geographically isolated populations and have traditionally been divided into the eastern (California-Chukchi) and western (Korean-Okhotsk) populations. Recent molecular comparisons confirm, based on differences in haplotypic frequencies, that these populations are genetically separated at the population-level. Both populations were commercially hunted, but only the eastern gray whale has returned to near pre-exploitation numbers. In contrast, the western population remains highly depleted, shows no apparent signs of recovery and its future survival remains uncertain. Research off Sakhalin Island, Russia between 1995 and 1999 has produced important new information on the present day conservation status of western gray whales and provided the basis for the World Conservation Union (IUCN) to list the population as 'Critically Endangered in 2000. The information presented here, in combination with potential impacts from anthropogenic threats throughout the range of this population, raises strong concerns about the recovery and continued survival of the western gray whale.

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We present measurements of Underlying Event observables in pp collisions at root s = 0 : 9 and 7 TeV. The analysis is performed as a function of the highest charged-particle transverse momentum p(T),L-T in the event. Different regions are defined with respect to the azimuthal direction of the leading (highest transverse momentum) track: Toward, Transverse and Away. The Toward and Away regions collect the fragmentation products of the hardest partonic interaction. The Transverse region is expected to be most sensitive to the Underlying Event activity. The study is performed with charged particles above three different p(T) thresholds: 0.15, 0.5 and 1.0 GeV/c. In the Transverse region we observe an increase in the multiplicity of a factor 2-3 between the lower and higher collision energies, depending on the track p(T) threshold considered. Data are compared to PYTHIA 6.4, PYTHIA 8.1 and PHOJET. On average, all models considered underestimate the multiplicity and summed p(T) in the Transverse region by about 10-30%.

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The ALICE experiment at the LHC has studied J/psi production at mid-rapidity in pp collisions at root s = 7 TeV through its electron pair decay on a data sample corresponding to an integrated luminosity L-int = 5.6 nb(-1). The fraction of J/psi from the decay of long-lived beauty hadrons was determined for J/psi candidates with transverse momentum p(t) > 1,3 GeV/c and rapidity vertical bar y vertical bar < 0.9. The cross section for prompt J/psi mesons, i.e. directly produced J/psi and prompt decays of heavier charmonium states such as the psi(2S) and chi(c) resonances, is sigma(prompt J/psi) (p(t) > 1.3 GeV/c, vertical bar y vertical bar < 0.9) = 8.3 +/- 0.8(stat.) +/- 1.1 (syst.)(-1.4)(+1.5) (syst. pol.) mu b. The cross section for the production of b-hadrons decaying to J/psi with p(t) > 1.3 GeV/c and vertical bar y vertical bar < 0.9 is a sigma(J/psi <- hB) (p(t) > 1.3 GeV/c, vertical bar y vertical bar < 0.9) = 1.46 +/- 0.38 (stat.)(-0.32)(+0.26) (syst.) mu b. The results are compared to QCD model predictions. The shape of the p(t) and y distributions of b-quarks predicted by perturbative QCD model calculations are used to extrapolate the measured cross section to derive the b (b) over bar pair total cross section and d sigma/dy at mid-rapidity.

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A 39-year-old woman with autosomal dominant polycystic kidney disease (ADPKD) presented with acromegaly and a pituitary macroadenoma. There was a family history of this renal disorder. She had undergone surgery for pituitary adenoma 6 years prior. Physical examination disclosed bitemporal hemianopsia and elevation of both basal growth hormone (GH) 106 ng/mL (normal 0-5) and insulin-like growth factor (IGF-1) 811 ng/mL (normal 48-255) blood levels. A magnetic resonance imaging scan disclosed a 3.0 cm sellar and suprasellar mass with both optic chiasm compression and left cavernous sinus invasion. Pathologic, cytogenetic, molecular and in silico analysis was undertaken. Histologic, immunohistochemical and ultrastructural studies of the lesion disclosed a sparsely granulated somatotroph adenoma. Standard chromosome analysis on the blood sample showed no abnormality. Sequence analysis of the coding regions of PKD1 and PKD2 employing DNA from both peripheral leukocytes and the tumor revealed the most common PKD1 mutation, 5014_5015delAG. Analysis of the entire SSTR5 gene disclosed the variant c.142C > A (p.L48M, rs4988483) in the heterozygous state in both blood and tumor, while no pathogenic mutations were noted in the MEN1, AIP, p27Kip1 and SSTR2 genes. To our knowledge, this is the fourth reported case of a GH-producing pituitary adenoma associated with ADPKD, but the first subjected to extensive morphological, ultrastructural, cytogenetic and molecular studies. The physical proximity of the PKD1 and SSTR5 genes on chromosome 16 suggests a causal relationship between ADPKD and somatotroph adenoma.

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We briefly review the characteristics of pituitary tumors associated with multiple endocrine neoplasia type 1. Multiple endocrine neoplasia type 1 is an autosomal-dominant disorder most commonly characterized by tumors of the pituitary, parathyroid, endocrine-gastrointestinal tract, and pancreas. A MEDLINE search for all available publications regarding multiple endocrine neoplasia type 1 and pituitary adenomas was undertaken. The prevalence of pituitary tumors in multiple endocrine neoplasia type 1 may vary from 10% to 60% depending on the studied series, and such tumors may occur as the first clinical manifestation of multiple endocrine neoplasia type 1 in 25% of sporadic and 10% of familial cases. Patients were younger and the time between initial and subsequent multiple endocrine neoplasia type 1 endocrine lesions was significantly longer when pituitary disease was the initial manifestation of multiple endocrine neoplasia type 1. Tumors were larger and more invasive and clinical manifestations related to the size of the pituitary adenoma were significantly more frequent in patients with multiple endocrine neoplasia type 1 than in subjects with non-multiple endocrine neoplasia type 1. Normalization of pituitary hypersecretion was much less frequent in patients with multiple endocrine neoplasia type 1 than in subjects with non-multiple endocrine neoplasia type 1. Pituitary tumors in patients with multiple endocrine neoplasia type 1 syndrome tend to be larger, invasive and more symptomatic, and they tend to occur in younger patients when they are the initial presentation of multiple endocrine neoplasia type 1.