1,832 research outputs found
Nova legislação, recomendação de doses de inoculantes e pré-inoculação: riscos ao sucesso da contribuição da fixação biológica do nitrogênio para a cultura da soja.
Implementação de sistema de gestão da qualidade ISO 17025 nas análises e ensaios com inoculantesmicrobianos de interesse agrícola no Laboratório de Biotecnologia do Solo da Embrapa Soja.
Inoculante é considerado, pela legislação brasileira, como todo produto que contém microrganismos com atuação favorável ao crescimento de plantas, havendo perspectivas de incrementos consideráveis no uso desses produtos pelos agricultores nos próximos anos. O Brasil é líder mundial na utilização de inoculantes contendo bactérias diazotróficas, em um mercado que, na safra de 2008/2009, foi superior a 20 milhões de doses, mais de 98% destinadas à cultura da soja. As estimativas são de que, só com a cultura da soja, o processo de fixação biológica do nitrogênio contribua com uma economia anual de US$ 6,6 bilhões no país, que deixam de ser gastos com o uso de fertilizantes nitrogenados. No Brasil, poucos laboratórios realizam análise de qualidade de inoculantes. O Laboratório de Biotecnologia do Solo da Embrapa Soja realiza dezenas de análises anualmente para atender a demandas de agricultores, de indústrias de inoculantes e de avaliação de novos produtos. Uma das metas atuais do laboratório é a de implementar a norma do sistema de qualidade ISO/IEC 17025 nas análises e ensaios com inoculantes microbianos. Essa meta visa atender a uma demanda crescente por qualidade de todos os setores produtivos, visando a acreditação e a rastreabilidade dos resultados.Fertbio
Verwey transition in FeO at high pressure: quantum critical behavior at the onset of metallization
We provide evidence for the existence of a {\em quantum critical point} at
the metallization of magnetite FeO at an applied pressure of GPa. We show that the present ac magnetic susceptibility data
support earlier resistivity data. The Verwey temperature scales with pressure
, with . The resistivity data shows a
temperature dependence , with above and
2.5 at the critical pressure, respectively. This difference in with
pressure is a sign of critical behavior at . The magnetic susceptibility
is smooth near the critical pressure, both at the Verwey transition and near
the ferroelectric anomaly. A comparison with the critical behavior observed in
the Mott-Hubbard and related systems is made.Comment: 5 pages, 5 figure
Teores de nutrientes e parâmetros fotossintéticos em genótipos de soja com diferentes níveis de tolerância à restrição hídrica.
A soja é uma das culturas de maior relevância econômica mundial, cujo N demandado é suprido pela fixação biológica de nitrogênio (FBN). Entretanto, a restrição hídrica pode afetar a sua fisiologia e nutrição, dependendo da tolerância genotípica à seca. O objetivo desse trabalho foi avaliar os teores de nutrientes e parâmetros fotossintéticos em genótipos de soja com diferentes tolerâncias à restrição hídrica. O experimento foi conduzido em delineamento inteiramente casualizado em arranjo fatorial 5 × 2, com sete repetições, empregando as linhagens R01-581F, R01-416F, R02-1325, que possuem capacidade de manter a FBN em condições de seca, e os padrões CD 215 e BRS 317, sensíveis, sob suprimento adequado de água (70% CC), ou sob restrição hídrica (30% CC) entre 45 e 55 dias após a emergência. Foram avaliados os teores de N, P, K, Ca, Mg, S, B, Cu, Fe, Mn e Zn na parte aérea, condutância estomática, concentração interna de CO2 e teor de clorofila (entre 45 e 55 dias). Em geral, os genótipos R01-581F, R01-416F e R02-1325 apresentaram maiores teores de nutrientes quando comparados aos padrões CD 215 e BRS 317, confirmando sua melhor condição nutricional sob restrição hídrica. A restrição hídrica afetou negativamente os parâmetros relacionados à fotossíntese.Fertbio
Mamld1 Knockdown Reduces Testosterone Production and Cyp17a1 Expression in Mouse Leydig Tumor Cells
MAMLD1 is known to be a causative gene for hypospadias. Although previous studies have indicated that MAMLD1 mutations result in hypospadias primarily because of compromised testosterone production around the critical period for fetal sex development, the underlying mechanism(s) remains to be clarified. Furthermore, although functional studies have indicated a transactivation function of MAMLD1 for the non-canonical Notch target Hes3, its relevance to testosterone production remains unknown. To examine these matters, we performed Mamld1 knockdown experiments.Mamld1 knockdown was performed with two siRNAs, using mouse Leydig tumor cells (MLTCs). Mamld1 knockdown did not influence the concentrations of pregnenolone and progesterone but significantly reduced those of 17-OH pregnenolone, 17-OH progesterone, dehydroepiandrosterone, androstenedione, and testosterone in the culture media. Furthermore, Mamld1 knockdown significantly decreased Cyp17a1 expression, but did not affect expressions of other genes involved in testosterone biosynthesis as well as in insulin-like 3 production. Hes3 expression was not significantly altered. In addition, while 47 genes were significantly up-regulated (fold change >2.0×) and 38 genes were significantly down-regulated (fold change <0.5×), none of them was known to be involved in testosterone production. Cell proliferation analysis revealed no evidence for compromised proliferation of siRNA-transfected MLTCs.The results, in conjunction with the previous data, imply that Mamld1 enhances Cyp17a1 expression primarily in Leydig cells and permit to produce a sufficient amount of testosterone for male sex development, independently of the Hes3-related non-canonical Notch signaling
Pubertal presentation in seven patients with congenital adrenal hyperplasia due to P450 Oxidoreductase deficiency
Context: P450 oxidoreductase (POR) is a crucial electron donor to all microsomal P450 cytochrome (CYP) enzymes including 17α-hydroxylase (CYP17A1), 21-hydroxylase (CYP21A2) and P450 aromatase. Mutant POR causes congenital adrenal hyperplasia with combined glucocorticoid and sex steroid deficiency. P450 oxidoreductase deficiency (ORD) commonly presents neonatally, with disordered sex development in both sexes, skeletal malformations, and glucocorticoid deficiency. \ud
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Objective: The aim of the study was to describe the clinical and biochemical characteristics of ORD during puberty. \ud
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Design: Clinical, biochemical, and genetic assessment of seven ORD patients (five females, two males) presenting during puberty was conducted. \ud
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Results: Predominant findings in females were incomplete pubertal development (four of five) and large ovarian cysts (five of five) prone to spontaneous rupture, in some only resolving after combined treatment with estrogen/progestin, GnRH superagonists, and glucocorticoids. Pubertal development in the two boys was more mildly affected, with some spontaneous progression. Urinary steroid profiling revealed combined CYP17A1 and CYP21A2 deficiencies indicative of ORD in all patients; all but one failed to mount an appropriate cortisol response to ACTH stimulation indicative of adrenal insufficiency. Diagnosis of ORD was confirmed by direct sequencing, demonstrating disease-causing POR mutations. \ud
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Conclusion: Delayed and disordered puberty can be the first sign leading to a diagnosis of ORD. Appropriate testosterone production during puberty in affected boys but manifest primary hypogonadism in girls with ORD may indicate that testicular steroidogenesis is less dependent on POR than adrenal and ovarian steroidogenesis. Ovarian cysts in pubertal girls may be driven not only by high gonadotropins but possibly also by impaired CYP51A1-mediated production of meiosis-activating sterols due to mutant POR
Recuperação e sobrevivência de Bradyrhizobium em sementes de soja tratadas com fungicidas e inseticidas.
O processo de fixação biológica do nitrogênio (FBN) representa um componente essencial para a viabilidade econômica da cultura da soja. No entanto, para um processo eficiente, um número mínimo de células viáveis de Bradyrhizobium deve estar presente para o estabelecimento da simbiose e o uso concomitante de produtos químicos, como inseticidas e fungicidas, pode comprometer a viabilidade das células. Neste estudo, foram avaliadas novas combinações de inoculantes e polímeros na presença de tratamento de sementes com fungicidas e inseticidas, em tratamento manual ou industrial. Foi constatado que novas formulações e aplicações de produtos nas sementes podem permitir a pré-inoculação por até 4 dias, considerando a sobrevivência de pelo menos 10 5 células/semente
The Optical System for the Large Size Telescope of the Cherenkov Telescope Array
The Large Size Telescope (LST) of the Cherenkov Telescope Array (CTA) is
designed to achieve a threshold energy of 20 GeV. The LST optics is composed of
one parabolic primary mirror 23 m in diameter and 28 m focal length. The
reflector dish is segmented in 198 hexagonal, 1.51 m flat to flat mirrors. The
total effective reflective area, taking into account the shadow of the
mechanical structure, is about 368 m. The mirrors have a sandwich structure
consisting of a glass sheet of 2.7 mm thickness, aluminum honeycomb of 60 mm
thickness, and another glass sheet on the rear, and have a total weight about
47 kg. The mirror surface is produced using a sputtering deposition technique
to apply a 5-layer coating, and the mirrors reach a reflectivity of 94%
at peak. The mirror facets are actively aligned during operations by an active
mirror control system, using actuators, CMOS cameras and a reference laser.
Each mirror facet carries a CMOS camera, which measures the position of the
light spot of the optical axis reference laser on the target of the telescope
camera. The two actuators and the universal joint of each mirror facet are
respectively fixed to three neighboring joints of the dish space frame, via
specially designed interface plate.Comment: In Proceedings of the 34th International Cosmic Ray Conference
(ICRC2015), The Hague, The Netherlands. All CTA contributions at
arXiv:1508.0589
DNA barcoding reveals the coral “laboratory-rat”, Stylophora pistillata encompasses multiple identities
Stylophora pistillata is a widely used coral “lab-rat” species with highly variable morphology and a broad biogeographic range (Red Sea to western central Pacific). Here we show, by analysing Cytochorme Oxidase I sequences, from 241 samples across this range, that this taxon in fact comprises four deeply divergent clades corresponding to the Pacific-Western Australia, Chagos-Madagascar-South Africa, Gulf of Aden-Zanzibar-Madagascar, and Red Sea-Persian/Arabian Gulf-Kenya. On the basis of the fossil record of Stylophora, these four clades diverged from one another 51.5-29.6 Mya, i.e., long before the closure of the Tethyan connection between the tropical Indo-West Pacific and Atlantic in the early Miocene (16–24 Mya) and should be recognised as four distinct species. These findings have implications for comparative ecological and/or physiological studies carried out using Stylophora pistillata as a model species, and highlight the fact that phenotypic plasticity, thought to be common in scleractinian corals, can mask significant genetic variation
Layer thickness dependence of the current induced effective field vector in Ta|CoFeB|MgO
The role of current induced effective magnetic field in ultrathin magnetic
heterostructures is increasingly gaining interest since it can provide
efficient ways of manipulating magnetization electrically. Two effects, known
as the Rashba spin orbit field and the spin Hall spin torque, have been
reported to be responsible for the generation of the effective field. However,
quantitative understanding of the effective field, including its direction with
respect to the current flow, is lacking. Here we show vector measurements of
the current induced effective field in Ta|CoFeB|MgO heterostructrures. The
effective field shows significant dependence on the Ta and CoFeB layers'
thickness. In particular, 1 nm thickness variation of the Ta layer can result
in nearly two orders of magnitude difference in the effective field. Moreover,
its sign changes when the Ta layer thickness is reduced, indicating that there
are two competing effects that contribute to the effective field. The relative
size of the effective field vector components, directed transverse and parallel
to the current flow, varies as the Ta thickness is changed. Our results
illustrate the profound characteristics of just a few atomic layer thick metals
and their influence on magnetization dynamics
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