2,262 research outputs found
Avaliação quantitativa da microbiota em solo de cultivo de soja transgĂȘnica em seis locais do Brasil.
A biomassa microbiana Ă© responsĂĄvel por funçÔes chave para a qualidade do solo, e o cultivo de soja transgĂȘnica bem como o uso de herbicidas pode causar alteraçÔes sobre esse importante componente biolĂłgico do solo. O objetivo do presente trabalho foi avaliar quantitativamente o carbono (CBM) e o nitrogĂȘnio (NBM) da biomassa microbiana de solo cultivado com soja transgĂȘnica e aplicação de herbicidas em seis locais do Brasil na safra 2005/2006. O delineamento experimental foi de bloco ao acaso, com seis repetiçÔes, em sistema de plantio direto. Os tratamentos foram: T1: soja transgĂȘnica + glifosato; T2: soja transgĂȘnica + herbicidas convencionais; T3: soja parental convencional + herbicidas convencionais; T4: soja transgĂȘnica + capina manual; T5: soja parental convencional + capina manual, combinados com trĂȘs cultivares em cada local estudado, totalizando 15 tratamentos. Os solos foram coletados no estĂĄgio R2 na profundidade 0-10 cm para a avaliação do CBM e do NBM. A anĂĄlise de contrastes mostrou que o CBM nĂŁo foi afetado pela transgenia, com exceção de Uberaba (MG). NĂŁo houve diferenças entre o manejo convencional da soja (soja e herbicidas convencionais) e o transgĂȘnico (soja transgĂȘnica com glifosato) em relação ao CBM, tambĂ©m com exceção de Uberaba. O NBM, em geral, nĂŁo foi afetado pela transgenia. Em dois locais (Ponta Grossa/PR e Passo Fundo/RS), o manejo convencional apresentou maior NBM, enquanto o manejo transgĂȘnico com glifosato foi superior em Luiz Eduardo MagalhĂŁes (BA). Conclui-se que o cultivo transgĂȘnico da soja nĂŁo afetou a biomassa microbiana do solo.Fertbio
Fixação biolĂłgica do nitrogĂȘnio em soja transgĂȘnica e aplicação de glifosato durante trĂȘs safras consecutivas no Brasil.
Rectification of radio frequency current in ferromagnetic nanowire
We report the rectification of a constant wave radio frequency (RF) current
by using a single-layer magnetic nanowire; a direct-current voltage is
resonantly generated when the RF current flows through the nanowire. The
mechanism of the rectification is discussed in terms of the spin torque diode
effect reported for magnetic tunnel junction devices and the rectification is
shown to be direct attributable to resonant spin wave excitation by the RF
current.Comment: 20 Pages, 4 figures, submitte
Leverage web analytics for real time website browsing recommendations
Trabalho apresentado no 5th World Conference on Information Systems and Technologies (WorldCISTâ17), 11-13 de abril 2017, Porto Santo, Madeira PortugalAs a websitesâ structure grow it is paramount to accommodate the
alignment of user needs and experience with the overall websitesâ purposes.
Toward this requirement, the proposed website navigation recommendation
system suggests to users, pages that might be of her interest based on past
successful navigation patterns of overall siteâs usage. Most of existing
recommendation systems adopts traditionally one of the web mining branches.
We take a different stance, on web mining usage, and alternatively considered
the real time enactment of web analytic tools supported analysis given their
current maturity and affordances. On this basis we provide a model, its
implementation and evaluation for navigation based recommendations
generation and delivery. The developed prototype adopted a SaaS orientation
to promote the underlying functionalities integration within any website.
Preliminary evaluationâs results seem to favor the validation of the present
contribution rational.N/
Cementing proteins provide extra mechanical stabilization to viral cages
The study of virus shell stability is key not only for gaining insights into viral biological cycles but also for using viral capsids in materials science. The strength of viral particles depends profoundly on their structural changes occurring during maturation, whose final step often requires the specific binding of âdecorationâ proteins (such as gpD in bacteriophage lambda) to the viral shell. Here we characterize the mechanical stability of gpD-free and gpD-decorated bacteriophage lambda capsids. The incorporation of gpD into the lambda shell imparts a major mechanical reinforcement that resists punctual deformations. We further interrogate lambda particle stability with molecular fatigue experiments that resemble the sub-lethal Brownian collisions of virus shells with macromolecules in crowded environments. Decorated particles are especially robust against collisions of a few kBT (where kB is the Boltzmannâs constant and T is the temperature ~300âK), which approximate those anticipated from molecular insults in the environmentWe acknowledge the MINECO of Spain (PIB2010US-00233, FIS3011-29493, Consolider CSD2010-00024, CAMprojectNo.S3009/MAT-1467), and the US National Science Foundation (MCB-1158107) for their financial support of this researc
Adenylate effects on protein phosphorylation in the interenvelope lumen of pea chloroplasts
A 64-kilodalton (kDa) protein, situated in the lumen between the inner and outer envelopes of pea (Pisum sativum L.) chloroplasts (Soll and Bennett 1988, Eur. J. Biochem., 175, 301â307) is shown to undergo reversible phosphorylation in isolated mixed envelope vesicles. It is the most conspicuously labelled protein after incubation of envelopes with 33 nmol·1-1 [-32P]ATP whereas incubation with 50 mol·1-1 [-32P]ATP labels most prominently two outer envelope proteins (86 and 23 kDa). Half-maximum velocity for phosphorylation of the 64-kDa protein occurs with 200 nmol·1-1 ATP, and around 40 mol·1-1 ATP for phosphorylation of the 86- and 23-kDa proteins, indicating the operation of two distinct kinases. GGuanosine-, uridine-, cytidine 5-triphosphate and AMP are poor inhibitors of the labelling of the 64-kDa protein with [-32P]ATP. On the other hand, ADP has a potent influence on the extent of labelling (half-maximal inhibition at 1â5 mol·1-1). The ADP-dependent appearance of 32P in ATP indicates that ADP acts by reversal of kinase activity and not as a competitive inhibitor. However, the most rapid loss of 32P from pre-labelled 64-kDa protein occurs when envelope vesicles are incubated with ATP t1/2=15 s at 20 molsd1-1 ATP). This induced turnover of phosphate appears to be responsible for the rapid phosphoryl turnover seen in situ
Mechanisms for slow strengthening in granular materials
Several mechanisms cause a granular material to strengthen over time at low
applied stress. The strength is determined from the maximum frictional force
F_max experienced by a shearing plate in contact with wet or dry granular
material after the layer has been at rest for a waiting time \tau. The layer
strength increases roughly logarithmically with \tau -only- if a shear stress
is applied during the waiting time. The mechanisms of strengthening are
investigated by sensitive displacement measurements and by imaging of particle
motion in the shear zone. Granular matter can strengthen due to a slow shift in
the particle arrangement under shear stress. Humidity also leads to
strengthening, but is found not to be its sole cause. In addition to these time
dependent effects, the static friction coefficient can also be increased by
compaction of the granular material under some circumstances, and by cycling of
the applied shear stress.Comment: 21 pages, 11 figures, submitted to Phys. Rev.
How long can you hold the filler:Maintenance and retrieval
This study attempts to reveal the mechanisms behind the online formation of Wh-Filler-Gap Dependencies (WhFGD). Specifically, we aim to uncover the way in which maintenance and retrieval work in WhFGD processing, by paying special attention to the information that is retrieved when the gap is recognized. We use the agreement attraction phenomenon (Wagers, M. W., Lau, E. F., & Phillips, C. (2009). Agreement attraction in comprehension: Representations and processes. Journal of Memory and Language, 61(2), 206-237) as a probe. The first and second experiments examined the type of information that is maintained and how maintenance is motivated, investigating the retrieved information at the gap for reactivated fillers and definite NPs. The third experiment examined the role of the retrieval, comparing reactivated and active fillers. We contend that the information being accessed reflects the extent to which the filler is maintained, where the reader is able to access fine-grained information including category information as well as a representation of both the head and the modifier at the verb
Localization of a 64-kDa phosphoprotein in the lumen between the outer and inner envelopes of pea chloroplasts
The identification and localization of a marker protein for the intermembrane space between the outer and inner chloroplast envelopes is described. This 64-kDa protein is very rapidly labeled by [Îł-32P]ATP at very low (30 nM) ATP concentrations and the phosphoryl group exhibits a high turnover rate. It was possible to establish the presence of the 64-kDa protein in this plastid compartment by using different chloroplast envelope separation and isolation techniques. In addition comparison of labeling kinetics by intact and hypotonically lysed pea chloroplasts support the localization of the 64-kDa protein in the intermembrane space. The 64-kDa protein was present and could be labeled in mixed envelope membranes isolated from hypotonically lysed plastids. Mixed envelope membranes incorporated high amounts of 32P from [Îł-32P]ATP into the 64-kDa protein, whereas separated outer and inner envelope membranes did not show significant phosphorylation of this protein. Water/Triton X-114 phase partitioning demonstrated that the 64-kDa protein is a hydrophilic polypeptide. These findings suggest that the 64-kDa protein is a soluble protein trapped in the space between the inner and outer envelope membranes. After sonication of mixed envelope membranes, the 64-kDa protein was no longer present in the membrane fraction, but could be found in the supernatant after a 110000 Ă g centrifugation
- âŠ