7,411 research outputs found
Some spectral equivalences between Schrodinger operators
Spectral equivalences of the quasi-exactly solvable sectors of two classes of
Schrodinger operators are established, using Gaudin-type Bethe ansatz
equations. In some instances the results can be extended leading to full
isospectrality. In this manner we obtain equivalences between PT-symmetric
problems and Hermitian problems. We also find equivalences between some classes
of Hermitian operators.Comment: 14 page
Beginning of the End of Cost Competitiveness in CEE Countries - Analysis of Dependence between Labor Costs and Internationalization of the Region
In order to exemplify the above econometric model I carried out empirical analysis of the companies listed on the Warsaw Stock Exchange, identifying the companies for which efficiency-seeking is the main internationalization motive. The analysis of internationalization of 26 companies during the years 1990-2010 clearly shows that a significant part of investments is located outside the territory of Poland, in the countries with lower labor costs. This fact confirms that CEE countries will gradually become less and less attractive in terms of costs not only for MNEs from developed countries but also for the companies originating from transition economies.Głównym celem artykułu jest weryfikacja, czy niski poziom kosztów pracy w Europie Środkowej i Wschodniej będący do tej pory jednym z czynników wpływających na konkurencyjność tego regionu pozostanie nim w dłuższej perspektywie czasowej. W pracy na podstawie próby wszystkich państw UE zbadano zależność pomiędzy poziomem internacjonalizacji (stan odpływu BIZ per capita) a kosztami pracy w sektorze przedsiębiorstw i GNP per capita. Analiza regresji potwierdziła istnienie zależności pomiędzy wyżej wymienionymi czynnikami. Oznacza to, że stopniowy wzrost kosztów pracy w państwach Europy Środkowej i Wschodniej prowadził będzie do stopniowego odpływu BIZ z tego regionu do państw bardziej konkurencyjnych kosztowo. W celu egzemplifikacji powyższych zależności w pracy dodatkowo przedstawiono analizę inwestycji zagranicznych polskich spółek notowanych na GPW, z których to 26 dokonało inwwestycji zagranicznych o wyraźnych motywach związanych z obniżeniem kosztów produkcji. Fakt ten potwierdza powolny spadek konkurencyjności kosztowej polskiej gospodarki, tym samym zmusza do poszukiwania nowych rozwiązań instytucjonalnych mogących utrzymać konkurencyjność polskiej gospodarki w długim okresie
A 3D Model of the 4GLS VUV-FEL Conceptual Design Including Improved Modelling of the Optical Cavity
The Conceptual Design Report for the 4th Generation Light Source (4GLS) at Daresbury Laboratory in the UK was published in Spring 2006. The proposal includes a low-Q cavity (also called a regenerative amplifier) FEL to generate variably-polarised, temporally-coherent radiation in the photon energy range 3-10eV. A new simulation code has been developed that incorporates the 3D FEL code Genesis 1.3 and which simulates in 3D the optical components and radiation propagation within the non-amplifying sections of an optical cavity*. This code is used to estimate the optimum low-Q cavity design and characterise the output from the 4GLS VUV-FEL
A meta-analysis of variables that predict significant intracranial injury in minor head trauma.
BACKGROUND: Previous studies have presented conflicting results regarding the predictive effect of various clinical symptoms, signs, and plain imaging for intracranial pathology in children with minor head injury. AIMS: To perform a meta-analysis of the literature in order to assess the significance of these factors and intracranial haemorrhage (ICH) in the paediatric population. METHODS: The literature was searched using Medline, Embase, Experts, and the grey literature. Reference lists of major guidelines were crosschecked. Control or nested case-control studies of children with head injury who had skull radiography, recording of common symptoms and signs, and head computed tomography (CT) were selected. OUTCOME VARIABLE: CT presence or absence of ICH. RESULTS: Sixteen papers were identified as satisfying criteria for inclusion in the meta-analysis, although not every paper contained data on every correlate. Available evidence gave pooled patient numbers from 1136 to 22 420. Skull fracture gave a relative risk ratio of 6.13 (95% CI 3.35 to 11.2), headache 1.02 (95% CI 0.62 to 1.69), vomiting 0.88 (95% CI 0.67 to 1.15), focal neurology 9.43 (2.89 to 30.8), seizures 2.82 (95% CI 0.89 to 9.00), LOC 2.23 (95% CI 1.20 to 4.16), and Glasgow Coma Scale (GCS) <15 of 5.51 (95% CI 1.59 to 19.0). CONCLUSIONS: There was a statistically significant correlation between intracranial haemorrhage and skull fracture, focal neurology, loss of consciousness, and GCS abnormality. Headache and vomiting were not found to be predictive and there was great variability in the predictive ability of seizures. More information is required about the current predictor variables so that more refined guidelines can be developed. Further research is currently underway by three large study groups
Optimal Topology of Aircraft Rib and Spar Structures Under Aeroelastic Loads
This work is funded by the Fixed Wing Project under NASA’s Fundamental Aeronautics Program.Peer reviewedPostprin
Development and evaluation of a screening tool to identify people with diabetes at increased risk of medication problems relating to hypoglycaemia and medication non-adherence
Abstract Aims: To develop and evaluate a screening tool to identify people with diabetes at increased risk of medication problems relating to hypoglycaemia and medication non-adherence. Methods: A retrospective audit of attendances at a diabetes outpatient clinic at a public, teaching hospital over a 16-month period was conducted. Logistic regression was undertaken to examine risk factors associated with medication problems relating to hypoglycaemia and medication non-adherence and the most predictive set of factors comprise the Diabetes Medication Risk Screening Tool. Evaluating the tool involved assessing sensitivity and specificity, positive and negative predictive values, cut-off scores, inter-rater reliability, and content validity. Results: The Diabetes Medication Risk Screening Tool comprises seven predictive factors: age, living alone, English language, mental and behavioural problems, comorbidity index score, number of medications prescribed, and number of high-risk medications prescribed. The tool has 76.5% sensitivity, 59.5% specificity, and has a 65.1% positive predictive value, and a 71.8% negative predictive value. A score of 27 or more out of 62 was associated with high-risk of a medication problem. The inter-rater reliability of the tool was high (κ = 0.79, 95% CI 0.75 - 0.84) and the content validity index was 99.4%. Conclusion: The Diabetes Medication Risk Screening Tool has good psychometric properties and can proactively identify people with diabetes at greatest risk of medication problems relating to hypoglycaemia and medication non-adherence
Transit System Evaluation Process: From Planning to Realization
Many frameworks exist to help transit agencies plan, operate, and monitor the performance of transit in rural and urban communities. No framework integrates these three critical business practices into one coherent and flexible framework useful to rural and small-sized cities. The primary objective of this research was to integrate planning, operations, and performance measurement activities into a framework designed to evaluate transit in the context of overall mobility. By combining planning, evaluation, and performance monitoring processes, a succinct framework useful to transit agencies and planners was created. In addition to city entities, colleges and universities operating or contracting transit systems also benefit from such a framework by creating a process that can be tailored to their needs as well. The framework outlines the activities necessary to complete a fixed route transit evaluation through an examination of the entire transportation system. Specific methodologies for each activity were not included in the framework because they must be customized to fit the needs and resources available to the evaluating entity but several example methods are presented in a case-study application of the proposed framework itself. The framework was tailored for use by rural and small cities and small- and medium-sized universities; however, it can be customized to meet the needs of any agencies or department regardless of the location. A case study of Clemson University’s on-campus transit route, operated by Clemson Area Transit, in Clemson, South Carolina revealed that the proposed framework worked well in bringing stakeholders together and achieving the intended objectives
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