66 research outputs found

    A Bayesian Interpretation of Extremim Estimators.

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    Extremum estimation is typically an ad hoc semi-parametric estimation procedure which is only justified on the basis of the asymptotic properties of the estimators. For a fixed finite data set, consider a large number of investigations using different extremum estimators to estimate the same parameter vector. The resulting empirical distribution of point estimates can be shown to coincide with a Bayesian posterior measure on the parameter space induced by a minimum information procedure. The Bayesian interpretation serves a number of purposes ranging from lending legitimacy to the use of those procedures in small sample problems, to helping prove asymptotic properties by reference to Bayes central limit theorems, to laying a foundation for combining point estimates from various extremum estimation experiments for statistical decision processes.EVALUATION ; ECONOMIC MODELS

    Can Islamic Banking Survive? A Micro-Evolutionary Perspective.

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    Islamic banking is a growing phenomenon which came into existence to satisfy the financial needs of devout Muslims who observe the prohibition of interest-based transactions. Many economists have studied the macroeconomic properties of this institution in the framework of an isolated and ideal Islamic economy. In this age of integrated global financial markets, the instantaneous transformation of an entire financial sector to profit-and-loss sharing is very unlikely. I present an evolutionary game-theoretic model in which devout Muslims, regular interest- based banks, and "weak" (hybrid) muslims/banks interact. The third type of agents is intended to represent the behavior of current Islamic banking, which is commonly criticized for mimicking interest-based systems. It is shown in this model that a critical initial mass of the "weak" types is necessary for the survival of the devout agents in a heterogeneous environment. Moreover, it is shown that the survival of the devout agents is predicated on the islamically-"weak" agents acting among themselves in an Islamic way.BANKING

    A Monte Carlo Study of Ec-Estimation in Panel Data Models with Limited Dependent Variables and Heterogeneity.

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    The EC (Estimation-Classification) estimator, and its companion EC-algorithm, were introduced in El- Gamal and Grether (1995), and their properties further analyzed in El-Gamal and Grether (1996). The purpose of EC estimation is to uncover heterogeneity in panel data models in a manner which is more parsimonious and computationally less costly than some of the standard methods (e.g. fixed effects). The latter concern is particularly evident in limited dependent variable models where no simple method of estimating fixed effects is available (e.g. probits).EVALUATION ; ECONOMIC MODELS

    A Consistent Nonparametric Test of Ergodicity for Time Series with Applications.

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    We propose a set of algorithms for testing the ergodicity of empirical time series, without reliance on a specific parametric framework. It is shown that the resulting test asymptotically obtains the correct size for stationary and nonstationary processes, and maximal power against non-ergodic but stationary alternatives. The test will not reject in the presence of nonstationarity that does not lead to ergodic failure. The work is linked to recent research on reformulations of the concept of integrated processes of order zero, and we demonstrate the means to operationalize new concepts of "short memory" for economic time series. Limited Monte Carlo evidence is provided with respect to power against the non-stationary and non-ergodic alternative of unit root processes. The method is used to investigate debates over stability of monetary aggregates relative to GDP, and the mean reversion hypothesis with respect to high frequency data on exchange rates.TESTS ; TIME SERIES

    RESPONSE OF Helianthus tuberosus L. TO ORGANIC AND BIO-ORGANIC FERTILIZERS

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    Two field experiments were conducted during the summer season of 2003 and 2004 to study the effect of organic and bio-organic fertilizers [esterna biofert, compost, biocompost and effective microorganisms (Em)] on vegetative growth, yield and physical and chemical components in tubers of local and fuseau Jerusalem artichoke cultivars. Results indicated that Em, biocompost and biofert significantly increased plant height, number of main and lateral shoots and dry weight as well as the concentrations of Chl (a+b), carotenoids and total carbohydrates in the leaves. Moreover, dry matter, inulin, nitrogen, phosphorus and potassium of tubers showed a significant increases. The highest vegetative growth and tuber yield were obtained when Em, biocompost and biofert were applied. The respective increase in lateral shoots, Chl (a + b), carotenoids, average tuber weight and size were higher in local cultivar. Whereas fuseau cultivar tubers showed greater dry matter than those of local variety. The application of Em, biocompost and biofert fertilizers in both local and fuseau cultivar gave the relatively higher yield with good quality

    Implementation of a bowel management program in the treatment of incontinence in children for primary healthcare providers

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    Objectives: Our surgical team has devised a bowel management program (BMP) as a basic approach for primary healthcare providers with the least use of resources.Background: Soiling in children is a major problem that has a serious impact on the child’s social and psychological life. Causes vary from idiopathic constipation to postoperative or neuropathic causes as meningomyelocele.Participants and methods: Seventy five children suffering from fecal incontinence were assessed and divided into true incontinence and pseudoincontinence groups. The BMP was applied to both categories in the form of proper diet control, enemas, drugs, and bowel habit alteration. The program was fashioned according to the age, type, severity, and response of each case. A fecal incontinence scoring system was used to assess the results.Results: All cases with pseudoincontinence attained 50% or more improvement in incontinence score whereas the true incontinence cases attained excellent results except in post high anorectal malformation repairs and neurologic groups.Conclusion: Most of the cases suffering from constipation with pseudoincontinence can be treated properly by BMPs, whereas the minority suffering from true incontinence need multidisciplinary work to achieve acceptable results.Keywords: anorectal malformations, bowel management program, chronic idiopathic constipation, fecal incontinence, Hirschsprung’s disea

    Low body mass index in long standing rheumatoid arthritis: relation to RA disease activity and functional indices

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    The aim of the work was to study the relationship between the body mass index (BMI) in longstanding rheumatoid arthritis (RA) and RA disease activity and functional indices. This study included 105 RA patients. For all patients, we recorded the presence of erosions on radiographs, the presence of subcutaneous nodules (SCN), the 28-tender joint count (TJC), 28-swollen joint count (SJC) scores, the visual analogue scale (VAS), physicians’ global assessments (PhGA), the erythrocyte sedimentation rate (ESR), and the rheumatoid factor (RF). The disease activity index (DAS28) and BMI were calculated and current treatment was recorded. Patients were divided into two groups: group I: BMI 25. Group I included 32 (30.5%) patients, whereas group II included 73 (69.5%) patients. There were statistically significant differences between the two groups regarding each of the following: SJC (p=0.006), erosions (p=0.006), DAS28 (p=0.016) and PhGA (p=0.007). All were higher in group I (underweight and normal) than in group II (overweight and obese). No statistically significant differences emerged regarding age (p=0.11), smoking (p=0.69), disease duration (p=0.46), TJC (p=0.14), SCN (p=1.00), HAQ (p=0.26), VAS (p=0.16), ESR (p=0.25), RF (p=0.54) and steroid cumulative dose (p=0.08). Low BMI in longstanding RA patients may indicate more active and erosive disease and it may be considered as a poor prognostic factor

    Numerical study of an individual Taylor bubble rising through stagnant liquids under laminar flow regime

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    Slug flow is one of the main flow regimes encountered in multiphase flow systems especially in oil and gas production systems. In the present study, the rise of single Taylor bubble through vertical stagnant Newtonian liquid is investigated by performing complete dimensionless treatment followed by an order of magnitude analysis of the terms of equations of motion. Based on this analysis, it is concluded that Froude, E€otv€os and Reynolds numbers are the sole physical parameters influencing the dimensionless slug flow equations. Using the guidelines of the order of magnitude analysis, computational fluid dynamics simulation is carried out to investigate the dynamics of Taylor bubbles in vertical pipe using the volume-of-fluid (VOF) method. Good agreement with previous experimental data and models available in the literature is established confirming that the density ratio, viscosity ratio and the initial ratio of bubble size to pipe diameter ðLTB=DÞ have minimal effect on the main hydrodynamic features of slug flow. Based on the developed results, correlations for the terminal velocity of the Taylor bubble and the dimensionless wall shear stress are proposed showing the significance of these main dimensionless parameters and support other important theoretical and experimental work available in the literature

    Significance of selenium in ameliorating the effects of irrigation deficit via improving photosynthesis efficiency, cell integrity, osmo-protectants, and oil profile of anise crop

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    Anise is one of the plants with therapeutic potential, which is classified among the most important medicinal plants with interesting biological effects. Its components could be perceived so as “natural” and “safe” alternatives to antibiotics as well as they are applied in different industries such as food and cosmetic purposes. Selenium (Se) is an essential micronutrient, however, its importance to improve oil yield and quality of anise has not been adequately investigated, specifically under drought. Therefore, two successive seasons were conducted to investigate the effect of selenium foliar application upon anise plants under drought stress. Selenium was applied at three different concentrations (0.0 1.0 and 2.0 mM denoted Se0, Se1 and Se2, respectively) along with two levels of crop evapotranspiration (ET): Full irrigation, 100% of ET (FI) and 60% of ET (DI). The promotive effect of combinations of DI × Se1 or Se2 (for Fv/Fm, RWC%, and MSI% in the first season) and DI × Se2 (for Fv/Fm, and MSI% in the second season) were as similar as FI × Se2. Compared to the counterpart control treatment (DI × Se0), the highest increases in total free amino acids (31.5 and 31.6%), total soluble sugars (84.2 and 86.4%) and free proline content (84.2 and 86.4%) were recorded with application of DI × Se2 practice in both seasons, respectively. Under DI, Se2 recorded the maximum values of root length, shoot fresh weight and shoot dry weight in the second season. Under drought, the increases in seed yield due to application of Se1 and Se2 amounted to 1.72 and 1.62 folds in the 1st season and 1.50 and 1.43 folds in 2nd one, respectively. The most effective practice for improving IWUE was Se1× DI in both seasons, followed by Se2 × DI. Based on the chromatographical detection, the maximum values of Anethole were recorded with FI × Se2 while L-Linalool has greatly increased with DI × Se2. In conclusion, the growers in arid and semi-arid zones are advised to use selenium (2.0 mM) in anise fertilization to mitigate the adverse impacts of drought, and keeping crop yield and quality

    General upper bound for distributing conferencing keys in arbitrary quantum networks

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    Secure quantum conferencing refers to a protocol where a number of trusted users generate exactly the same secret key to confidentially broadcast private messages. By a modification of the techniques first introduced in [Pirandola, arXiv:1601.00966], we derive a single-letter upper bound for the maximal rates of secure conferencing in a quantum network with arbitrary topology, where the users are allowed to perform the most powerful local operations assisted by two-way classical communications, and the quantum systems are routed according to the most efficient multipath flooding strategies. More precisely, our analysis allows us to bound the ultimate rates that are achievable by single-message multiple-multicast protocols, where N senders distribute N independent secret keys, and each key is to be shared with an ensemble of M receivers
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