4,172 research outputs found
Stability of additive-free water-in-oil emulsions
We calculate ion distributions near a planar oil-water interface within
non-linear Poisson-Boltzmann theory, taking into account the Born self-energy
of the ions in the two media. For unequal self-energies of cations and anions,
a spontaneous charge separation is found such that the water and oil phase
become oppositely charged, in slabs with a typical thickness of the Debye
screening length in the two media. From the analytical solutions, the
corresponding interfacial charge density and the contribution to the
interfacial tension is derived, together with an estimate for the
Yukawa-potential between two spherical water droplets in oil. The parameter
regime is explored where the plasma coupling parameter exceeds the
crystallization threshold, i.e. where the droplets are expected to form
crystalline structures due to a strong Yukawa repulsion, as recently observed
experimentally. Extensions of the theory that we discuss briefly include
numerical calculations on spherical water droplets in oil, and analytical
calculations of the linear PB-equation for a finite oil-water interfacial
width.Comment: 9 pages, 4 figures, accepted by JPCM for proceedings of LMC
Концепция управления персоналом банка
Рассмотрены проблемы управления персоналом в коммерческих банках Украины в современных условиях перехода страны к рыночным отношениям. Даны предложения о том, что концепция работы с персоналом в Национальном банке может быть построена на взаимосвязи ее основных механизмов.Розглянуті проблеми управління персоналом в комерційних банках України в сучасних умовах переходу країни до ринкових відносин. Дані пропозиції про те, що концепція роботи з персоналом в Національному банку може бути побудований на взаємозв'язку її основних механізмів.The problems of personnel management in the commercial banks of Ukraine in the modern terms of transition of country to the market conditions are considered. Suggestions that conception of work with a personnel in the National bank can be built on intercommunication of its basic mechanisms are given
Modelling asset correlations: A nonparametric approach
This article proposes a time-varying nonparametric estimator and a time-varying semiparametric estimator of the correlation matrix. We discuss representation, estimation based on kernel smoothing and inference. An extensive Monte Carlo simulation study is performed to compare the semiparametric and nonparametric models with the DCC speci fication. Our bivariate simulation results show that the semiparametric and nonparametric models are best in DGPs with gradual changes or structural breaks in correlations. However, in DGPs with rapid changes or constancy in correlations the DCC delivers the best outcome. Moreover, in multivariate simulations the semiparametric and nonparametric models fare the best in DGPs with substantial time-variability in correlations, while when allowing for little variability in the correlations the DCC is the dominant speci fication. The methodologies are illustrated by estimating the correlations for two interesting portfolios. The rst portfolio consists of the equity sectors SPDRs and the S&P 500 composite, while the second one contains major currencies that are actively traded in the foreign exchange market. Portfolio evaluation results show that the nonparametric estimator generally dominates its competitors, with a statistically significant lower portfolio variance
Protocol for Physiotherapy Or TVT Randomised Efficacy Trial (PORTRET): a multicentre randomised controlled trial to assess the cost-effectiveness of the tension free vaginal tape versus pelvic floor muscle training in women with symptomatic moderate to severe stress urinary incontinence
Estimation of individual beneficial and adverse effects of intensive glucose control for patients with type 2 diabetes
AIMS/HYPOTHESIS: Intensive glucose control reduces the risk of vascular complications while increasing the risk of severe hypoglycaemia at a group level. We sought to estimate individual beneficial and adverse effects of intensive glucose control in patients with type 2 diabetes. METHODS: We performed a post hoc analysis of the Action in Diabetes and Vascular Disease: Preterax and Diamicron MR Controlled Evaluation (ADVANCE) trial, a randomised controlled trial evaluating standard vs intensive glucose control (HbA1c target ≤6.5% [48 mmol/mol]). In 11,140 participants, we estimated the individual 5 year absolute risk reduction (ARR) for the composite outcome of major micro- and macrovascular events and absolute risk increase (ARI) for severe hypoglycaemia for intensive vs standard glucose control. Predictions were based on competing risks models including clinical characteristics and randomised treatment. RESULTS: Based on these models, 76% of patients had a substantial estimated 5 year ARR for major vascular events (>1%, 5 year number-needed-to-benefit [NNTB5] 200). Similarly, 36% of patients had a substantial estimated ARI for severe hypoglycaemia (5 year number-needed-to-harm [NNTH5] 200). When assigning similar or half the weight to severe hypoglycaemia compared with a major vascular event, net benefit was positive in 85% or 99% of patients, respectively. Limiting intensive treatment to the 85% patient subgroup had no significant effect on the overall incidence of major vascular events and severe hypoglycaemia compared with treating all patients. CONCLUSIONS/INTERPRETATION: Taking account of the effects of intensive glucose control on major micro- and macrovascular events and severe hypoglycaemia for individual patients, the estimated net benefit was positive in the majority of the participants in the ADVANCE trial. The estimated individual effects can inform treatment decisions once individual weights assigned to positive and adverse effects have been specified. TRIAL REGISTRATION: ClinicalTrials.gov NCT00145925
A review of human error in marine engine maintenance
Maritime safety involves minimizing error in all aspects of the marine system. Human error hasreceived much importance, being responsible for about 80% of the maritime accident worldwide. Currently,more attention has been focused to reduce human error in marine engine maintenance. On-board marineengine maintenance activities are often complex, where seafarers conduct maintenance activities in variousmarine environmental (i.e. extreme weather, ship motions, noise, and vibration) and operational (i.e. workoverload and stress) conditions. These environmental and operational conditions, in combination with generichuman error tendencies, results in innumerable forms of error. There are numerous accidents that happeneddue to the human error during the maintenance activities of a marine engine. The most severe human errorresults in accidents due to is a loss of life. Moreover, there are other consequences too such as delaying theproductivity of marine operations which results in the financial loss. This study reviews methods that arecurrently available for identifying, reporting and managing human error in marine engine maintenance. As abasis for this discussion, authors provide an overview of approaches for investigating human error, and adescription of marine engine maintenance activities and environmental and operational characteristics
The relationship between mental disorders and actual and desired subjective social status
Mental disorders are associated with lower subjective social status (SSS), but a more nuanced understanding of this relationship is needed. We examined the influence of disorder age of onset and recency on SSS and studied whether mental disorders are also associated with the discrepancy between actual and desired SSS.Method Data are from the baseline and second wave of the Netherlands Mental Health Survey and Incidence Study-2 (NEMESIS-2). Mental disorders were assessed with the Composite International Diagnostic Interview (CIDI 3.0), while both actual and desired SSS were assessed with a ten-rung ladder. Linear regression was used to examine the association between mental disorders and SSS.Results Of 5303 participants, 2237 had a lifetime mental disorder at baseline. These participants reported significantly lower actual SSS (6.28) at follow-up than healthy participants (6.66, B = -0.38 [95% CI -0.48 to -0.27], p < 0.001) and a significantly greater actual-desired SSS discrepancy (1.14 v. 1.05 after controlling for actual SSS, B = 0.09 [0.01-0.17], p = 0.024). Lower age of onset of the first mental disorder was marginally significantly associated with lower actual SSS (B = 0.006 [0.000-0.012], p = 0.046). More recent disorders were also associated with lower actual SSS (B = 0.015 [0.005-0.026], p = 0.005), such that participants whose disorder remitted a ≥6 years before baseline were statistically indistinguishable from healthy participants.Conclusions Lifetime mental disorders are associated with lower actual SSS and a slightly greater discrepancy between actual and desired SSS. However, people with mental disorders in (long-term) remission have a similar social status as healthy participants
The historical fertility transition at the micro level: Southern Sweden 1815-1939
<b>Background</b>: We know a great deal about the historical fertility transition at the macro level. The dominating focus on the macro level in previous research on the fertility transition means, however, that to a large extent we lack knowledge about details of the decline and empirical tests of the leading explanatory frameworks. <b>Objective</b>: Our aim is to explore socioeconomic fertility differentials in an industrializing community, to gain insight about the details and discuss possible mechanisms. The study starts well before industrialization and finishes at the end of the transition. <b>Methods</b>: We use longitudinal individual-level data from the Scanian Economic-Demographic Database, which contains demographic as well as socioeconomic information, including occupation, landholding, and income. In the analysis we use hazard regressions with shared frailty at the family level. <b>Results</b>: The transition involved not only parity-specific stopping but also spacing. While the upper social strata had higher fertility prior to the transition, they started to control their fertility earlier, by the 1880s, and also more consistently. Farmers, the middle class, and skilled workers followed in the decades after, and unskilled workers with some additional delay. <b>Conclusions</b>: These findings are partly inconsistent with several of the major explanations in the literature, such as mortality decline, increased female labor force participation, and a quantity-quality trade-off, but consistent with an innovation process where new ideas and attitudes about family limitation spread from the elite to other social groups. <b>Comments</b>: Further studies are required to empirically test the innovation-diffusion theory
Experimental determination of the quasi-particle decay length in a superconducting quantum well
We have investigated experimentally the electronic transport properties of a
two-dimensional electron gas (2DEG) present in an AlSb/InAs/AlSb quantum well,
where part of the toplayer has been replaced by a superconducting Nb strip,
with an energy gap . By measuring the lateral electronic transport
underneath the superconductor, and comparing the experimental results with a
model based on the Bogoliubov-de Gennes equation and the Landauer-B\"uttiker
formalism, we obtain a decay length for
electrons. This decay length corresponds to an interface transparency
between the Nb and InAs. Using this value, we infer an
energy gap in the excitation spectrum of the SQW of .Comment: Revtex, 3 PostScript figure
Nilpotent orbits and codimension-two defects of 6d N=(2,0) theories
We study the local properties of a class of codimension-2 defects of the 6d
N=(2,0) theories of type J=A,D,E labeled by nilpotent orbits of a Lie algebra
\mathfrak{g}, where \mathfrak{g} is determined by J and the outer-automorphism
twist around the defect. This class is a natural generalisation of the defects
of the 6d theory of type SU(N) labeled by a Young diagram with N boxes. For any
of these defects, we determine its contribution to the dimension of the Higgs
branch, to the Coulomb branch operators and their scaling dimensions, to the 4d
central charges a and c, and to the flavour central charge k.Comment: 57 pages, LaTeX2
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