527 research outputs found
Avaliação da ameaça de erosão hídrica na ilha da Madeira - Portugal
Na estimativa da erosão hídrica na ilha da Madeira aplicou-se a Equação de Wischmeier.
Recorreu-se a relações para estimar a erosividade (R); foi adequado o Índice Modificado de
Fournier e relação IMF/R. cartografada a erosividade os restantes parâmetros resultaram da
metodologia. IMF varia entre 81.0–465.0 mm. A equação R = 1.365 IMF1.408 estima a erosividade
anual precipitação, com dados de Funchal-Observatório, sul de Portugal e valores da literatura,
obtendo-se R ≈ 2 964 MJ mm h−1 ha−1 ano−1, variando entre 660- 8515. Erosão média é 28 t ha−1
ano−1, excedendo 100 em >4.9% da área. A ameaça de erosão adveio da divisão do volume de
solo dos horizontes mobilizáveis, pela erosão anual. O resultado -número de anos- que ocorre a
perda do solo de cobertura. Apesar do tempo para esgotamento do solo, ser >20 000 anos, a
ameaça de erosão, alta e muito alta, é relevante. Estas ameaças (depleção <100 anos) ocorrem
em 263 km2 (35.6%); na ameaça muito alta (depleção em <10 anos) a área é ≈40 km2 (5.4%).
Encostas com declives muito elevados estão associadas a ameaças altas (ou muito altas). Efetuouse a análise da precipitação 20 de Fevereiro, obtendo-se um período de retorno superior a 100
anos.info:eu-repo/semantics/publishedVersio
Proton pump inhibitors in patients treated with aspirin and clopidogrel after acute coronary syndrome
INTRODUCTION:
Clopidogrel is an antiplatelet agent converted to its active metabolite by cytochrome P-450 isoenzymes. Numerous drugs are known to inhibit P-450 isoenzymes, including proton pump inhibitors (PPIs), which are often associated with aspirin and clopidogrel to prevent adverse gastrointestinal effects. In vitro studies first showed that PPIs reduced the antiplatelet effect of clopidogrel, while recent clinical studies have raised concerns that the addition of a PPI to clopidogrel in acute coronary syndrome (ACS) patients could actually increase the risk of recurrent cardiovascular events.
OBJECTIVE:
The aim of this study was to evaluate whether the prescription of a PPI conferred a worse prognosis in patients discharged with aspirin and clopidogrel treatment after ACS.
METHODS:
A total of 876 patients admitted with ACS and discharged with aspirin and clopidogrel, with a planned duration of at least six months, from January 2004 to March 2008, were reviewed. Patients were classified in two groups according to whether or not a PPI was prescribed at discharge. The PPIs considered were those mainly metabolized by cytochrome P-450 2C19. We excluded patients with insufficient information available on either prescription or clinical records that could allow clearly confirm or exclude exposure to a PPI. Primary end points were six-month all-cause mortality and the composite of death, myocardial infarction and unstable angina at six months.
RESULTS:
Of the 802 patients considered for further analysis, 274 (34.2%) individuals were medicated with a PPI in addition to dual antiplatelet therapy. Patients taking PPIs were older, more often had renal insufficiency and less often had a history of coronary revascularization and smoking. They more often presented with Killip class >I and lower hemoglobin concentration on admission. There were no significant differences between the two groups in terms of medical treatment (during hospital stay and at discharge) or invasive procedures. By multivariate analysis, independent and positive predictors of PPI prescription were older age and lower hemoglobin concentration on admission. Patients taking PPIs had a slightly higher prevalence of six-month mortality (6.5% vs. 3.9%) and of the composite end point (12.9% vs. 9.2%), although without statistical significance. By multivariate analysis including potential confounding variables, the prescription of a PPI on top of aspirin and clopidogrel was still n ot associated with a worse prognosis.
CONCLUSIONS:
In the present study, PPI precription in addition to aspirin and clopidogrel after ACS was not associated with a worse six-month prognosis
Unforgeable Quantum Encryption
We study the problem of encrypting and authenticating quantum data in the
presence of adversaries making adaptive chosen plaintext and chosen ciphertext
queries. Classically, security games use string copying and comparison to
detect adversarial cheating in such scenarios. Quantumly, this approach would
violate no-cloning. We develop new techniques to overcome this problem: we use
entanglement to detect cheating, and rely on recent results for characterizing
quantum encryption schemes. We give definitions for (i.) ciphertext
unforgeability , (ii.) indistinguishability under adaptive chosen-ciphertext
attack, and (iii.) authenticated encryption. The restriction of each definition
to the classical setting is at least as strong as the corresponding classical
notion: (i) implies INT-CTXT, (ii) implies IND-CCA2, and (iii) implies AE. All
of our new notions also imply QIND-CPA privacy. Combining one-time
authentication and classical pseudorandomness, we construct schemes for each of
these new quantum security notions, and provide several separation examples.
Along the way, we also give a new definition of one-time quantum authentication
which, unlike all previous approaches, authenticates ciphertexts rather than
plaintexts.Comment: 22+2 pages, 1 figure. v3: error in the definition of QIND-CCA2 fixed,
some proofs related to QIND-CCA2 clarifie
Controllable Entanglement of Lights in a Five-Level System
We analyze the nonlinear optical response of a five-level system under a
novel configuration of electro-magnetically induced transparency. We show that
a giant Kerr nonlinearity with a relatively large cross-phase modulation
coefficient that occurs in such system may be used to produce an efficient
photon-photon entanglement. We demonstrate that such photon-photon entanglement
is practically controllable and hence facilitates promising applications in
quantum information and computation.Comment: 13 pages, 4 figures, 1 column. We have added a section in which the
distortion of pulses due to the dispersion is considere
Timed inhibition of CDC7 increases CRISPR-Cas9 mediated templated repair.
Repair of double strand DNA breaks (DSBs) can result in gene disruption or gene modification via homology directed repair (HDR) from donor DNA. Altering cellular responses to DSBs may rebalance editing outcomes towards HDR and away from other repair outcomes. Here, we utilize a pooled CRISPR screen to define host cell involvement in HDR between a Cas9 DSB and a plasmid double stranded donor DNA (dsDonor). We find that the Fanconi Anemia (FA) pathway is required for dsDonor HDR and that other genes act to repress HDR. Small molecule inhibition of one of these repressors, CDC7, by XL413 and other inhibitors increases the efficiency of HDR by up to 3.5 fold in many contexts, including primary T cells. XL413 stimulates HDR during a reversible slowing of S-phase that is unexplored for Cas9-induced HDR. We anticipate that XL413 and other such rationally developed inhibitors will be useful tools for gene modification
Detection of multipartite entanglement with two-body correlations
We show how to detect entanglement with criteria built from simple two-body
correlation terms. Since many natural Hamiltonians are sums of such correlation
terms, our ideas can be used to detect entanglement by energy measurement. Our
criteria can straightforwardly be applied for detecting different forms of
multipartite entanglement in familiar spin models in thermal equilibrium.Comment: 5 pages including 2 figures, LaTeX; for the proceedings of the DPG
spring meeting, Berlin, March 200
Genetic diversity of Brazilian isolates of feline immunodeficiency virus
We isolated Feline immunodeficiency virus (FIV) from three adult domestic cats, originating from two open shelters in Brazil. Viruses were isolated from PBMC following co-cultivation with the feline T-lymphoblastoid cell line MYA-1. All amplified env gene products were cloned directly into pGL8MYA. The nucleic acid sequences of seven clones were determined and then compared with those of previously described isolates. The sequences of all of the Brazilian virus clones were distinct and phylogenetic analysis revealed that all belong to subtype B. Three variants isolated from one cat and two variants were isolated from each of the two other cats, indicating that intrahost diversity has the potential to pose problems for the treatment and diagnosis of FIV infection
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