117 research outputs found

    1-Benzoyl-5-phenyl-2-(propan-2-yl)-1,2,3,4-tetra­hydro­pyrimidin-4-one

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    The tetra­hydro­pyrimidinone ring in the title compound, C20H20N2O2, is in a half-boat conformation with the N—C—N C atom 0.580 (2) Å out of the plane defined by the remaining five atoms. In the crystal structure, mol­ecules are connected into centrosymmetric dimers via N—H⋯O inter­actions. The dimeric aggregates are linked into supra­molecular chains along the a axis via C—H⋯π inter­actions

    Performance analyses of optical burst-switching networks

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    Predictors of gastrointestinal lesions on endoscopy in iron deficiency anemia without gastrointestinal symptoms

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    <p>Abstract</p> <p>Background</p> <p>Iron deficiency anaemia (IDA) due to occult gastrointestinal (GI) blood loss usually remains unnoticed until patient become symptomatic. There is sparse data in IDA patients without gastrointestinal symptoms. This study was designed to find out the frequency and predictors of endoscopic lesions in IDA without gastrointestinal symptoms. Cross-sectional study performed on a convenience sample of consecutive subjects.</p> <p>Methods</p> <p>Ninety five consecutive patients with laboratory based diagnosis of IDA having no gastrointestinal symptoms were interviewed and their clinical and biochemical variables were recorded. All the study patients underwent esophago-gastroduodenoscopy (EGD) and colonoscopy. Endoscopic findings were documented as presence/absence of bleeding related lesion and presence/absence of cause of IDA. Multiple logistic regressions were performed to identify variables significantly related to outcome variables.</p> <p>Results</p> <p>Possible cause of anaemia was found in 71% and bleeding related lesions were found in 53% of patients. Upper gastrointestinal tract lesions were found in 41% of patients with bleeding related lesions. On multivariable logistic regression; advancing age, low mean corpuscular volume (MCV ≤ 60 fl), and positive fecal occult blood test were predictive factors for bleeding related GI lesions and cause of IDA</p> <p>Conclusion</p> <p>Clinical and Biochemical markers can predict gastrointestinal lesions on endoscopy in IDA patients without gastrointestinal symptoms. High proportion of upper gastrointestinal involvement warrants EGD as initial endoscopic procedure however, this needs validation by further studies.</p

    Development and calibration of a currency trading strategy using global optimization

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    We have developed a new financial indicator—called the Interest Rate Differentials Adjusted for Volatility (IRDAV) measure—to assist investors in currency markets. On a monthly basis, we rank currency pairs according to this measure and then select a basket of pairs with the highest IRDAV values. Under positive market conditions, an IRDAV based investment strategy (buying a currency with high interest rate and simultaneously selling a currency with low interest rate, after adjusting for volatility of the currency pairs in question) can generate significant returns. However, when the markets turn for the worse and crisis situations evolve, investors exit such money-making strategies suddenly, and—as a result—significant losses can occur. In an effort to minimize these potential losses, we also propose an aggregated Risk Metric that estimates the total risk by looking at various financial indicators across different markets. These risk indicators are used to get timely signals of evolving crises and to flip the strategy from long to short in a timely fashion, to prevent losses and make further gains even during crisis periods. Since our proprietary model is implemented in Excel as a highly nonlinear “black box” computational procedure, we use suitable global optimization methodology and software—the Lipschitz Global Optimizer solver suite linked to Excel—to maximize the performance of the currency basket, based on our selection of key decision variables. After the introduction of the new currency trading model and its implementation, we present numerical results based on actual market data. Our results clearly show the advantages of using global optimization based parameter settings, compared to the typically used “expert estimates” of the key model parameters.post-prin

    Comparative effectiveness and safety of non-vitamin K antagonists for atrial fibrillation in clinical practice: GLORIA-AF Registry

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    Background and purpose: Prospectively collected data comparing the safety and effectiveness of individual non-vitamin K antagonists (NOACs) are lacking. Our objective was to directly compare the effectiveness and safety of NOACs in patients with newly diagnosed atrial fibrillation (AF). Methods: In GLORIA-AF, a large, prospective, global registry program, consecutive patients with newly diagnosed AF were followed for 3&nbsp;years. The comparative analyses for (1) dabigatran vs rivaroxaban or apixaban and (2) rivaroxaban vs apixaban were performed on propensity score (PS)-matched patient sets. Proportional hazards regression was used to estimate hazard ratios (HRs) for outcomes of interest. Results: The GLORIA-AF Phase III registry enrolled 21,300 patients between January 2014 and December 2016. Of these, 3839 were prescribed dabigatran, 4015 rivaroxaban and 4505 apixaban, with median ages of 71.0, 71.0, and 73.0&nbsp;years, respectively. In the PS-matched set, the adjusted HRs and 95% confidence intervals (CIs) for dabigatran vs rivaroxaban were, for stroke: 1.27 (0.79–2.03), major bleeding 0.59 (0.40–0.88), myocardial infarction 0.68 (0.40–1.16), and all-cause death 0.86 (0.67–1.10). For the comparison of dabigatran vs apixaban, in the PS-matched set, the adjusted HRs were, for stroke 1.16 (0.76–1.78), myocardial infarction 0.84 (0.48–1.46), major bleeding 0.98 (0.63–1.52) and all-cause death 1.01 (0.79–1.29). For the comparison of rivaroxaban vs apixaban, in the PS-matched set, the adjusted HRs were, for stroke 0.78 (0.52–1.19), myocardial infarction 0.96 (0.63–1.45), major bleeding 1.54 (1.14–2.08), and all-cause death 0.97 (0.80–1.19). Conclusions: Patients treated with dabigatran had a 41% lower risk of major bleeding compared with rivaroxaban, but similar risks of stroke, MI, and death. Relative to apixaban, patients treated with dabigatran had similar risks of stroke, major bleeding, MI, and death. Rivaroxaban relative to apixaban had increased risk for major bleeding, but similar risks for stroke, MI, and death. Registration: URL: https://www.clinicaltrials.gov. Unique identifiers: NCT01468701, NCT01671007. Date of registration: September 2013

    Comparative effectiveness and safety of non-vitamin K antagonists for atrial fibrillation in clinical practice: GLORIA-AF Registry

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    Anticoagulant selection in relation to the SAMe-TT2R2 score in patients with atrial fibrillation. the GLORIA-AF registry

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    Aim: The SAMe-TT2R2 score helps identify patients with atrial fibrillation (AF) likely to have poor anticoagulation control during anticoagulation with vitamin K antagonists (VKA) and those with scores &gt;2 might be better managed with a target-specific oral anticoagulant (NOAC). We hypothesized that in clinical practice, VKAs may be prescribed less frequently to patients with AF and SAMe-TT2R2 scores &gt;2 than to patients with lower scores. Methods and results: We analyzed the Phase III dataset of the Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation (GLORIA-AF), a large, global, prospective global registry of patients with newly diagnosed AF and ≥1 stroke risk factor. We compared baseline clinical characteristics and antithrombotic prescriptions to determine the probability of the VKA prescription among anticoagulated patients with the baseline SAMe-TT2R2 score &gt;2 and ≤ 2. Among 17,465 anticoagulated patients with AF, 4,828 (27.6%) patients were prescribed VKA and 12,637 (72.4%) patients an NOAC: 11,884 (68.0%) patients had SAMe-TT2R2 scores 0-2 and 5,581 (32.0%) patients had scores &gt;2. The proportion of patients prescribed VKA was 28.0% among patients with SAMe-TT2R2 scores &gt;2 and 27.5% in those with scores ≤2. Conclusions: The lack of a clear association between the SAMe-TT2R2 score and anticoagulant selection may be attributed to the relative efficacy and safety profiles between NOACs and VKAs as well as to the absence of trial evidence that an SAMe-TT2R2-guided strategy for the selection of the type of anticoagulation in NVAF patients has an impact on clinical outcomes of efficacy and safety. The latter hypothesis is currently being tested in a randomized controlled trial. Clinical trial registration: URL: https://www.clinicaltrials.gov//Unique identifier: NCT01937377, NCT01468701, and NCT01671007

    Packet delay in optical circuit-switched networks

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    A seismic resistant design algorithm for laying and shielding of optical fiber cables

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    This paper considers a long-haul optical fiber cable, connecting two points on the Earth&#039;s surface that passes through earthquake-prone or other sensitive areas. Different segments of the cable are characterized by different protection levels, where a higher level through shielding represents a more costly and more resilient segment. This leads to a multi-objective optimization problem, where the two objectives are 1) the total cost of the cable and 2) the total number of potential repairs along the cable likely to be caused by earthquakes. As a measure of seismic risk, we use the concept of cable repair rate used in the civil engineering community. In our models, ground motion intensity data are used to estimate the cable repair rate, and a graph of a triangulated irregular network is used to represent the Earth&#039;s surface. We formulate this optimization problem as a multi-objective shortest path problem and solve it by a variant of the label setting algorithm. Two approximate algorithms, an interval-partition-based label-setting algorithm and an evolutionary algorithm, are also presented as methods of computational cost reduction for large-scale cases, and their results are compared. The solution leads to a Pareto front or an approximate Pareto front that enables us to choose the path and protection of the cable to either minimize cost for a given risk level or minimize risk for a given budget

    On the accuracy of the opc approximation for a symmetric overflow loss model

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    The overflow priority classification approximation (OPCA) and Erlang&#039;s fixed-point approximation (EFPA) are distinct methods for estimating blocking probabilities in overflow loss networks. Mounting numerical evidence has indicated that OPCA provides superior accuracy than EFPA in many circumstances. Furthermore, it has been proven that P EFPA ≤ P OPCA for a symmetric overflow loss network called the distributed server model, where P x is the blocking probability estimate yielded by approximation x {EFPA, OPCA}. The distributed server model is an ideal &quot;proving ground&quot; because the exact blocking probability, P exact, can be calculated with the Erlang B formula, yet the state dependencies caused by mutual overflow are retained. The present article proves the OPC Conjecture, P OPCA ≤ P exact. This new result establishes that OPCA is always equally or more accurate relative to EFPA for the distributed server model and suggests OPCA has utility in more general overflow loss networks. The proof of P OPCA ≤ P exact turned out to be challenging, since OPCA is remarkably close to the exact solution, requiring delicate inequality arguments on the Maclaurin series of both solutions. Another contribution is the derivation of new tight bounds and limiting regimes for the blocking probabilities yielded by OPCA and EFPA in the case of critical loading. The simple and tight lower bound derived for OPCA can serve as a tight lower bound for the Erlang B blocking probability in the case of critical loading
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