1,278 research outputs found

    Intersection Bounds: Estimation and Inference

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    We develop a practical and novel method for inference on intersection bounds, namely bounds defined by either the infimum or supremum of a parametric or nonparametric function, or equivalently, the value of a linear programming problem with a potentially infinite constraint set. We show that many bounds characterizations in econometrics, for instance bounds on parameters under conditional moment inequalities, can be formulated as intersection bounds. Our approach is especially convenient for models comprised of a continuum of inequalities that are separable in parameters, and also applies to models with inequalities that are non-separable in parameters. Since analog estimators for intersection bounds can be severely biased in finite samples, routinely underestimating the size of the identified set, we also offer a median-bias-corrected estimator of such bounds as a by-product of our inferential procedures. We develop theory for large sample inference based on the strong approximation of a sequence of series or kernel-based empirical processes by a sequence of "penultimate" Gaussian processes. These penultimate processes are generally not weakly convergent, and thus non-Donsker. Our theoretical results establish that we can nonetheless perform asymptotically valid inference based on these processes. Our construction also provides new adaptive inequality/moment selection methods. We provide conditions for the use of nonparametric kernel and series estimators, including a novel result that establishes strong approximation for any general series estimator admitting linearization, which may be of independent interest

    Intersection bounds: estimation and inference

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    We develop a practical and novel method for inference on intersection bounds, namely bounds deļ¬ned by either the inļ¬mum or supremum of a parametric or nonparametric function, or equivalently, the value of a linear programming problem with a potentially inļ¬nite constraint set. Our approach is especially convenient for models comprised of a continuum of inequalities that are separable in parameters, and also applies to models with inequalities that are non-separable in parameters. Since analog estimators for intersection bounds can be severely biased in ļ¬nite samples, routinely underestimating the size of the identiļ¬ed set, we also oļ¬€er a median-bias-corrected estimator of such bounds as a natural by-product of our inferential procedures. We develop theory for large sample inference based on the strong approximation of a sequence of series or kernel-based empirical processes by a sequence of "penultimate" Gaussian processes. These penultimate processes are generally not weakly convergent, and thus non-Donsker. Our theoretical results establish that we can nonetheless perform asymptotically valid inference based on these processes. Our construction also provides new adaptive inequality/moment selection methods. We provide conditions for the use of nonparametric kernel and series estimators, including a novel result that establishes strong approximation for any general series estimator admitting linearization, which may be of independent interest.

    Intersection Bounds: estimation and inference

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    We develop a practical and novel method for inference on intersection bounds, namely bounds defined by either the infimum or supremum of a parametric or nonparametric function, or equivalently, the value of a linear programming problem with a potentially infinite constraint set. Our approach is especially convenient in models comprised of a continuum of inequalities that are separable in parameters, and also applies to models with inequalities that are non-separable in parameters. Since analog estimators for intersection bounds can be severely biased in finite samples, routinely underestimating the length of the identified set, we also offer a (downward/upward) median unbiased estimator of these (upper/lower) bounds as a natural by-product of our inferential procedure. Furthermore, our method appears to be the first and currently only method for inference in nonparametric models with a continuum of inequalities. We develop asymptotic theory for our method based on the strong approximation of a sequence of studentized empirical processes by a sequence of Gaussian or other pivotal processes. We provide conditions for the use of nonparametric kernel and series estimators, including a novel result that establishes strong approximation for general series estimators, which may be of independent interest. We illustrate the usefulness of our method with Monte Carlo experiments and an empirical example.

    Dampak Penerapan Good Governance, Sistem Informasi Akuntansi dan Sistem Pengendalian Internal Terhadap Kinerja Instansi Pemerintah

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    This study examines the effect of implementing good governance, accounting information systems, and internal control systems on the performance of Yahokimo district government agencies. testing was carried out on a sample of 97 respondents. The sample method used is purposive sampling. data collection is done by direct survey. Hypothesis testing was tested empirically using moderated regression.  The results showed that the implementation of Good Governance had a significant positive effect on the Performance of the Yahokimo Regency Government Agencies, the Accounting Information System had a significant positive effect on the Performance of the Yahokimo Regency Government Agencies, the Internal Control System had a significant positive effect on the Performance of the Yahokimo Regency Government Agencies and the influence of the Implementation of Good Governance, Information Systems Accounting and Internal Control Systems simultaneously affect the Performance of Government Agencies of Yahokimo Regency

    Microbial diversity and potential pathogens in onamental fish aquarium water

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    Ā© The Author(s), 2012. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PLoS ONE 7 (2012): e39971, doi:10.1371/journal.pone.0039971.Ornamental fishes are among the most popular and fastest growing categories of pets in the United States (U.S.). The global scope and scale of the ornamental fish trade and growing popularity of pet fish in the U.S. are strong indicators of the myriad economic and social benefits the pet industry provides. Relatively little is known about the microbial communities associated with these ornamental fishes or the aquarium water in which they are transported and housed. Using conventional molecular approaches and next generation high-throughput amplicon sequencing of 16S ribosomal RNA gene hypervariable regions, we characterized the bacterial community of aquarium water containing common goldfish (Carassius auratus) and Chinese algae eaters (Gyrinocheilus aymonieri) purchased from seven pet/aquarium shops in Rhode Island and identified the presence of potential pathogens. Our survey identified a total of 30 phyla, the most common being Proteobacteria (52%), Bacteroidetes (18%) and Planctomycetes (6%), with the top four phyla representing >80% of all sequences. Sequences from our water samples were most closely related to eleven bacterial species that have the potential to cause disease in fishes, humans and other species: Coxiella burnetii, Flavobacterium columnare, Legionella birminghamensis, L. pneumophila, Vibrio cholerae, V. mimicus. V. vulnificus, Aeromonas schubertii, A. veronii, A. hydrophila and Plesiomonas shigelloides. Our results, combined with evidence from the literature, suggest aquarium tank water harboring ornamental fish are an understudied source for novel microbial communities and pathogens that pose potential risks to the pet industry, fishes in trade, humans and other species

    Could the real (not virtual) static observer exist outside a Schwarzschild black hole?

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    The aim of this Letter is rather pedagogical. We considered the static spherically symmetric ensemble of observers, having finite bare mass and trying to measure geometrical and physical properties of the environmental static (Schwarzschild) space-time. It is shown that, using the photon rockets (which the mass together with the mass of their fuel is also taken into account) they can managed to keep themselves on the fixed value of radius. The process of diminishing the total bare mass up to zero lasts infinitely long time. It is important that the problem is solved self-consistently, i.e., with full account for the back reaction of both bare mass and radiation from rockets on the space-time geometry.Comment: 7 page

    Experimental model of lead nephropathy. I. Continuous high-dose lead administration

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    Experimental model of lead nephropathy. I. Continuous high-dose lead administration. This study followed the progression of lead nephropathy in male Sprague-Dawley rats (E) administered lead acetate (0.5%) continuously in drinking water for periods ranging from 1 to 12 months. Control animals (C) were pair-fed. Observations included renal pathology by light and electron microscopy, wet and dry kidney weights, and glomerular filtration rate (GFR) to assess renal function. Urinary excretion of lead, the enzymes N-acetyl-beta-D-glucosaminidase (NAG) and glutathione-S-transferase (GST), and brush border antigens (BB50, CG9, and HF5) were utilized to explore possible markers of kidney injury. GFR was increased significantly after three months of lead exposure, but was decreased significantly after 12 months. Kidney wet weights were significantly greater in E than C from three months on. Kidney dry weight/wet weight ratio was constant up to three months, but decreased in E at 12 months. Glomerular diameters were normal at all time periods; the nephromegaly was related primarily to hypertrophy of proximal tubules. Lead inclusion bodies were found in nuclei of proximal convoluted tubules and pars recta at all times. Tubular atrophy and interstitial fibrosis first appeared at six months, and increased in severity thereafter. Brush borders of proximal tubules were disrupted at one and three months, but recovered thereafter. Focal and segmental glomerulosclerosis was observed in 2 of 10 rats at 12 months. Arteries and arterioles remained normal at all time periods. Urinary NAG was elevated in E above C after three months of lead exposure. However, urinary NAG in C also increased with age, obscuring changes in the 12 month E rats. GST was elevated after three months of lead administration in E, not without an attendant age-related increase in C rats. In three-month E rats, urinary brush border antigens were increased above C, but were decreased at six and 12 months, correlating with the morphologic changes in brush border. We conclude that a high dose of lead in rats may initially stimulate both renal cortical hypertrophy and an increase in GFR. Later, the adverse effects of lead on the tubulointerstitium predominate, and GFR falls. The urinary marker, NAG, was abnormal in the early stages of the disease, but age-related changes obscured its utility at later stages; urinary GST appeared to be a more consistent marker of injury

    The EC and real estate rents in Brussels

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    Real estate prices in Brussels started to increase at a very rapid rate in 1987-1988. This happened a few years before the European Community had to decide whether the Commission would remain in Brussels, and whether the European Parliament would be moved to Brussels. The main purpose of the paper is to analyze whether the European Community influenced real estate rents in Brussels during tghe period 1980-1992, and whether this influence has increased over time. We find evidence of a significant rent increase due to the EC after 1988.info:eu-repo/semantics/publishe

    All-Cause and Cause-Specific Mortality Among Black and White North Carolina State Prisoners, 1995ā€“2005

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    We compared mortality rates among state prisoners and other state residents to identify prisonersā€™ healthcare need

    Raloxifene for women with Alzheimer disease: A randomized controlled pilot trial

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    OBJECTIVE: To determine whether raloxifene, a selective estrogen receptor modulator, improves cognitive function compared with placebo in women with Alzheimer disease (AD) and to provide an estimate of cognitive effect. METHODS: This pilot study was conducted as a randomized, double-blind, placebo-controlled trial, with a planned treatment of 12 months. Women with late-onset AD of mild to moderate severity were randomly allocated to high-dose (120 mg) oral raloxifene or identical placebo provided once daily. The primary outcome compared between treatment groups at 12 months was change in the Alzheimer's Disease Assessment Scale, cognitive subscale (ADAS-cog). RESULTS: Forty-two women randomized to raloxifene or placebo were included in intent-to-treat analyses (mean age 76 years, range 68-84), and 39 women contributed 12-month outcomes. ADAS-cog change scores at 12 months did not differ significantly between treatment groups (standardized difference 0.03, 95% confidence interval -0.39 to 0.44, 2-tailed p = 0.89). Raloxifene and placebo groups did not differ significantly on secondary analyses of dementia rating, activities of daily living, behavior, or a global cognition composite score. Caregiver burden and caregiver distress were similar in both groups. CONCLUSIONS: Results on the primary outcome showed no cognitive benefits in the raloxifene-treated group. CLASSIFICATION OF EVIDENCE: This study provides Class I evidence that for women with AD, raloxifene does not have a significant cognitive effect. The study lacked the precision to exclude a small effect
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