Sao Paulo State University

About: Sao Paulo State University is a education organization based out in São Paulo, Brazil. It is known for research contribution in the topics: Population & Large Hadron Collider. The organization has 55715 authors who have published 100436 publications receiving 1375332 citations.

Déficit hídrico e os processos morfológico e fisiológico das plantas

Abstract: Esta breve revisao de literatura tem como objetivo abordar alguns aspectos dos fatores morfologicos e fisiologicos que, direta ou indiretamente, influenciam na habilidade das plantas em adaptar-se a diferentes condicoes de deficit hidrico durante seu crescimento e desenvolvimento. A sensibilidade do desenvolvimento das folhas ao deficit hidrico pode mudar no transcorrer do dia ou nas diferentes estacoes do ano, porem a limitacao de expansao na area foliar pode ser considerada como uma primeira reacao das plantas a esse deficit. Plantas cultivadas sob condicoes adequadas de suprimento hidrico sao, normalmente, menos resistentes ao deficit hidrico e, quando da ocorrencia rapida do deficit hidrico, os mecanismos morfofisiologicos sao severamente afetados, pois a planta necessitaria adaptar-se rapidamente a esta situacao de deficit; entretanto, quando o deficit hidrico ocorre gradualmente e/ou no inicio do ciclo, mais facilmente ocorre a adaptacao das plantas. A tolerância da planta ao deficit hidrico parece ser um importante mecanismo de resistencia para manter o processo produtivo em condicoes de baixa disponibilidade de agua as plantas. "Por isso, a importância de se abordar alguns aspectos dos fatores morfologicos e fisiologicos que influenciam a habilidade das plantas na adaptacao a situacoes de deficit hidrico."

Upper Limits on the Rates of Binary Neutron Star and Neutron Star-Black Hole Mergers from Advanced LIGO’s First Observing Run

Abstract: We report here the non-detection of gravitational waves from the merger of binary–neutron star systems and neutron star–black hole systems during the first observing run of the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO). In particular, we searched for gravitational-wave signals from binary–neutron star systems with component masses $\in [1,3]\,{M}_{\odot }$ and component dimensionless spins <0.05. We also searched for neutron star–black hole systems with the same neutron star parameters, black hole mass $\in [2,99]\,{M}_{\odot }$, and no restriction on the black hole spin magnitude. We assess the sensitivity of the two LIGO detectors to these systems and find that they could have detected the merger of binary–neutron star systems with component mass distributions of 1.35 ± 0.13 M ⊙ at a volume-weighted average distance of ~70 Mpc, and for neutron star–black hole systems with neutron star masses of 1.4 M ⊙ and black hole masses of at least 5 M ⊙, a volume-weighted average distance of at least ~110 Mpc. From this we constrain with 90% confidence the merger rate to be less than 12,600 Gpc−3 yr−1 for binary–neutron star systems and less than 3600 Gpc−3 yr−1 for neutron star–black hole systems. We discuss the astrophysical implications of these results, which we find to be in conflict with only the most optimistic predictions. However, we find that if no detection of neutron star–binary mergers is made in the next two Advanced LIGO and Advanced Virgo observing runs we would place significant constraints on the merger rates. Finally, assuming a rate of ${10}_{-7}^{+20}$ Gpc−3 yr−1, short gamma-ray bursts beamed toward the Earth, and assuming that all short gamma-ray bursts have binary–neutron star (neutron star–black hole) progenitors, we can use our 90% confidence rate upper limits to constrain the beaming angle of the gamma-ray burst to be greater than $2\buildrel{\circ}\over{.} {3}_{-1.1}^{+1.7}$ ($4\buildrel{\circ}\over{.} {3}_{-1.9}^{+3.1}$).

Enzymatic toxins from snake venom: structural characterization and mechanism of catalysis.

Abstract: Snake venoms are cocktails of enzymes and non-enzymatic proteins used for both the immobilization and digestion of prey. The most common snake venom enzymes include acetylcholinesterases, l-amino acid oxidases, serine proteinases, metalloproteinases and phospholipases A(2) . Higher catalytic efficiency, thermal stability and resistance to proteolysis make these enzymes attractive models for biochemists, enzymologists and structural biologists. Here, we review the structures of these enzymes and describe their structure-based mechanisms of catalysis and inhibition. Some of the enzymes exist as protein complexes in the venom. Thus we also discuss the functional role of non-enzymatic subunits and the pharmacological effects of such protein complexes. The structures of inhibitor-enzyme complexes provide ideal platforms for the design of potent inhibitors which are useful in the development of prototypes and lead compounds with potential therapeutic applications.