A photon transport problem with a time-dependent point source

We consider a time-dependent problem of photon transport in an interstellar cloud with a point photon source modeled by a Dirac δ functional. The existence of a unique distributional solution to this problem is established by using the theory of continuous semigroups of operators on locally convex spaces coupled with a constructive approach for producing spaces of generalized functions

Constraints of T conformation of carp azide hemoglobin on Fe site structure

AbstractThe iron site structure modifications induced by the transition from the quaternary R to T structure in ferric carp azide hemoglobin have been detected from analysis of multiple scattering resonances in the XANES (X-ray absorption near edge structure) spectra. High signal-to-noise XANES spectra measured at the Frascati ‘wiggler’ synchrotron radiation facility reveal that the forces on the Fe active site, due to the transition from the R to T quaternary conformation, only induce the tilting of the porphyrin plane and probably also of the proximal histidine. The variation of the Fe-N mean distance is not detected by XANES spectroscopy and therefore it is less than 0.01 Å

Efeitos de doses e formas de aplicação de reguladores de crescimento em uvas sem sementes, cv. BRS Clara, em região tropical.

O objetivo deste trabalho foi avaliar o efeito do uso dos reguladores vegetais, ácido giberélico e tidiazuron, no tamanho de bagas da cultivar BRS Clara em Região Tropical. Os experimentos foram conduzidos em 2006 e 2007, na Estação Experimental de Viticultura Tropical, em Jales-SP, região noroeste do Estado de São Paulo, em plantas da cv. BRS Clara. Foram testadas diferentes concentrações de GA3 aplicadas isoladamente, combinadas com Crop Set ou tidiazuron, em aplicações únicas ou sequênciais (2 e 4 vezes). As avaliações foram feitas por ocasião da maturação das uvas, considerando-se a massa fresca dos cachos, dos engaços e das bagas, determinadas por meio de balança analítica; o comprimento e o diâmetro médio das bagas, utilizando-se de paquímetro; e o teor de sólidos solúveis (SS), por meio de refratômetro manual. Os experimentos foram conduzidos em delineamento experimental de blocos casualizados, representados por uma planta, com 15 repetições, no ano de 2006, e 10 repetições, no ano de 2007. Os dados foram submetidos à análise de variância e, para a comparação das médias dos tratamentos, foi utilizado o teste Skott Nott, ao nível de 5% de probabilidade. Observou-se que o uso dos reguladores promoveu o crescimento das bagas na cultivar BRS Clara em todos os tratamentos, diferindo da testemunh

Ultimate response dynamics achieved with gas sensors based on self-heated nanowires

Bias current applied to conductometric gas sensors consisting of individual metal oxide nanowires can be used to heat them up to the temperature necessary for sensing. This approach in combination with the good sensitivity and stability of metal-oxide nanowires, can be used to develop prototypes with low power requirements (few tens of microwatts). Here, we present new sensors devices based on this approach that display fast dynamic performance only limited by the gas-solid interaction kinetics,. © 2009

Is stance detection topic-independent and cross-topic generalizable? - A reproduction study

NWO406.D1.19.073Algorithms and the Foundations of Software technolog

The role of Zn ions in the interaction between SARS-CoV-2 orf7a protein and BST2/tetherin

In this paper, we provide evidence that Zn2+ ions play a role in the SARS-CoV-2 virus strategy to escape the immune response mediated by the BST2-tetherin host protein. This conclusion is based on sequence analysis and molecular dynamics simulations as well as X-ray absorption experiments [1]

Growth study of indium-catalyzed silicon nanowires by plasma enhanced chemical vapor deposition

Indium was used as a catalyst for the synthesis of silicon nanowires in a plasma enhanced chemical vapor deposition reactor. In order to foster the catalytic activity of indium, the indium droplets had to be exposed to a hydrogen plasma prior to nanowire growth in a silane plasma. The structure of the nanowires was investigated as a function of the growth conditions by electron microscopy and Raman spectroscopy. The nanowires were found to crystallize along the , or growth direction. When growing on the and directions, they revealed a similar crystal quality and the presence of a high density of twins along the {111} planes. The high density and periodicity of these twins lead to the formation of hexagonal domains inside the cubic structure. The corresponding Raman signature was found to be a peak at 495 cm−1, in agreement with previous studies. Finally, electron energy loss spectroscopy indicates an occasional migration of indium during growt

The role of Zn ions in the interaction between SARS-CoV-2 orf7a protein and BST2/tetherin

In this paper, we provide evidence that Zn2+ ions play a role in the SARS-CoV-2 virus strategy to escape the immune response mediated by the BST2-tetherin host protein. This conclusion is based on sequence analysis and molecular dynamics simulations as well as X-ray absorption experiments

Zn-induced interactions between SARS-CoV-2 orf7a and BST2/Tetherin

We present in this work a first X-ray Absorption Spectroscopy study of the interactions of Zn with human BST2/tetherin and SARS-CoV-2 orf7a proteins as well as with some of their complexes. The analysis of the XANES region of the measured spectra shows that Zn binds to BST2, as well as to orf7a, thus resulting in the formation of BST2-orf7a complexes. This structural information confirms the the conjecture, recently put forward by some of the present Authors, according to which the accessory orf7a (and possibly also orf8) viral protein are capable of interfering with the BST2 antiviral activity. Our explanation for this behavior is that, when BST2 gets in contact with Zn bound to the orf7a Cys(15) ligand, it has the ability of displacing the metal owing to the creation of a new disulfide bridge across the two proteins. The formation of this BST2-orf7a complex destabilizes BST2 dimerization, thus impairing the antiviral activity of the latter

Distance to range edge determines sensitivity to deforestation

It is generally assumed that deforestation affects a species consistently across space, however populations near their geographic range edge may exist at their niche limits and therefore be more sensitive to disturbance. We found that both within and across Atlantic Forest bird species, populations are more sensitive to deforestation when near their range edge. In fact, the negative effects of deforestation on bird occurrences switched to positive in the range core (>829 km), in line with Ellenberg’s rule. We show that the proportion of populations at their range core and edge varies across Brazil, suggesting deforestation effects on communities, and hence the most appropriate conservation action, also vary geographically