9,001 research outputs found
Wavelet texture analysis of on-line acquired images for paper formation assessment and monitoring
http://www.sciencedirect.com/science/article/B6TFP-4TN82BP-2/2/0f2b38841a24101a06bac25004632e0
Integrated environmental and economic assessment of current and future fuel cell vehicles
Light-duty vehicles contribute considerably to global greenhouse gas emissions. Fuel cell vehicles (FCVs) may play a key role in mitigating these emissions without facing the same limitations in range and refueling time as battery electric vehicles (BEVs). In this study, we assess the environmental impacts and costs of a polymer electrolyte membrane fuel cell system (FCS) for use in light-duty FCVs and integrate these results into a comparative evaluation between FCVs, BEVs, and internal combustion engine vehicles (ICEVs).Swisselectric ResearchSwiss Competence Centre for Energy and MobilitySwiss Petroleum Associatio
The Impact of Organization Costs when Firm-selection Matters
How does an increase in organization costs (i.e. costs which arise when labor unions organize firm's workforces) affect the industry struc-ture, wage inequality and welfare? In the present paper, we build a model with costly and endogenous unionization, heterogeneous firms as well as free market entry/exit. In such a setting, we show that the share of low-productive firms operating in the market decreases (in-creases) in organization costs if those costs are relatively low (high). If more low-productive firms are active in the market, consumption and hence welfare decline because prices are, on average, higher (vice versa). As such, an increase in organization costs and thus a decline in unionization rates could be welfare-reducing. In addition, we find a hump-shaped relationship between organization costs and wage in-equality. These results suggest that a policy aiming to reduce union-ization by an increase in organization costs can but not necessarily have to be an improvement of the economic performance
Assessment of Sustainability Governance in Higher Education Institutions - a Systemic Tool using a Governance Equalizer
The paper aims to add to the discussion on sustainability governance in higher education institutions by examining the role of sustainability assessment and introducing an assessment tool inspired by systemic thinking and centered on a ‘governance equalizer’. It discusses recent research and argues that the complexity inherent in sustainability governance remains to be addressed adequately. While a number of models and frameworks have been proposed, most of them remain caught between narrow, management-oriented approaches on the one hand, and rather abstract approaches that provide little guidance for improving the field on the other. Sustainability assessment tools represent a potential way to bridge this gap. While there are existing tools which include issues of sustainability governance, these are often limited to aspects that are easily quantifiable and neglect more complex aspects. Against this background, the article proposes an alternative tool to assess sustainability governance in higher education institutions. The tool is based on a multi-case study in Germany and has been tested in a series of workshops. Drawing on the concept of a ‘governance equalizer’, it focuses on the functional requirements of sustainability governance in five dimensions - politics, profession, organization, knowledge, and the public—and how they are addressed by the HEI. The tool raises the level of abstraction in order to capture complexity, but at the same time keeps sight of governance structures, processes, instruments, and practices. It combines clearly defined criteria that are assessed using carefully developed maturity scales with a focus on stakeholder participation and knowledge
Refinement for Transition Systems with Responses
Motivated by the response pattern for property specifications and
applications within flexible workflow management systems, we report upon an
initial study of modal and mixed transition systems in which the must
transitions are interpreted as must eventually, and in which implementations
can contain may behaviors that are resolved at run-time. We propose Transition
Systems with Responses (TSRs) as a suitable model for this study. We prove that
TSRs correspond to a restricted class of mixed transition systems, which we
refer to as the action-deterministic mixed transition systems. We show that
TSRs allow for a natural definition of deadlocked and accepting states. We then
transfer the standard definition of refinement for mixed transition systems to
TSRs and prove that refinement does not preserve deadlock freedom. This leads
to the proposal of safe refinements, which are those that preserve deadlock
freedom. We exemplify the use of TSRs and (safe) refinements on a small
medication workflow.Comment: In Proceedings FIT 2012, arXiv:1207.348
NATbox: a network analysis toolbox in R
Background:
There has been recent interest in capturing the functional relationships (FRs) from high-throughput assays using suitable computational techniques. FRs elucidate the working of genes in concert as a system as opposed to independent entities hence may provide preliminary insights into biological pathways and signalling mechanisms. Bayesian structure learning (BSL) techniques and its extensions have been used successfully for modelling FRs from expression profiles. Such techniques are especially useful in discovering undocumented FRs, investigating non-canonical signalling mechanisms and cross-talk between pathways. The objective of the present study is to develop a graphical user interface (GUI), NATbox: Network Analysis Toolbox in the language R that houses a battery of BSL algorithms in conjunction with suitable statistical tools for modelling FRs in the form of acyclic networks from gene expression profiles and their subsequent analysis.
Results:
NATbox is a menu-driven open-source GUI implemented in the R statistical language for modelling and analysis of FRs from gene expression profiles. It provides options to (i) impute missing observations in the given data (ii) model FRs and network structure from gene expression profiles using a battery of BSL algorithms and identify robust dependencies using a bootstrap procedure, (iii) present the FRs in the form of acyclic graphs for visualization and investigate its topological properties using network analysis metrics, (iv) retrieve FRs of interest from published literature. Subsequently, use these FRs as structural priors in BSL (v) enhance scalability of BSL across high-dimensional data by parallelizing the bootstrap routines.
Conclusion:
NATbox provides a menu-driven GUI for modelling and analysis of FRs from gene expression profiles. By incorporating readily available functions from existing R-packages, it minimizes redundancy and improves reproducibility, transparency and sustainability, characteristic of open-source environments. NATbox is especially suited for interdisciplinary researchers and biologists with minimal programming experience and would like to use systems biology approaches without delving into the algorithmic aspects. The GUI provides appropriate parameter recommendations for the various menu options including default parameter choices for the user. NATbox can also prove to be a useful demonstration and teaching tool in graduate and undergraduate course in systems biology. It has been tested successfully under Windows and Linux operating systems. The source code along with installation instructions and accompanying tutorial can be found at: http://bioinformatics.ualr.edu/natboxWiki/index.php/Main_Page. </p
Exact sampling of self-avoiding paths via discrete Schramm-Loewner evolution
We present an algorithm, based on the iteration of conformal maps, that
produces independent samples of self-avoiding paths in the plane. It is a
discrete process approximating radial Schramm-Loewner evolution growing to
infinity. We focus on the problem of reproducing the parametrization
corresponding to that of lattice models, namely self-avoiding walks on the
lattice, and we propose a strategy that gives rise to discrete paths where
consecutive points lie an approximately constant distance apart from each
other. This new method allows us to tackle two non-trivial features of
self-avoiding walks that critically depend on the parametrization: the
asphericity of a portion of chain and the correction-to-scaling exponent.Comment: 18 pages, 4 figures. Some sections rewritten (including title and
abstract), numerical results added, references added. Accepted for
publication in J. Stat. Phy
Long-term lithium treatment in bipolar disorder. effects on glomerular filtration rate and other metabolic parameters
.BACKGROUND:
Concerns about potential adverse effects of long-term exposure to lithium as a mood-stabilizing treatment notably include altered renal function. However, the incidence of severe renal dysfunction; rate of decline over time; effects of lithium dose, serum concentration, and duration of treatment; relative effects of lithium exposure vs. aging; and contributions of sex and other factors all remain unclear.
METHODS:
Accordingly, we acquired data from 12 collaborating international sites and 312 bipolar disorder patients (6142 person-years, 2669 assays) treated with lithium carbonate for 8-48 (mean 18) years and aged 20-89 (mean 56) years. We evaluated changes of estimated glomerular filtration rate (eGFR) as well as serum creatinine, urea-nitrogen, and glucose concentrations, white blood cell count, and body-mass index, and tested associations of eGFR with selected factors, using standard bivariate contrasts and regression modeling.
RESULTS:
Overall, 29.5% of subjects experienced at least one low value of eGFR ( 55; risk of ≥2 low values was 18.1%; none experienced end-stage renal failure. eGFR declined by 0.71%/year of age and 0.92%/year of treatment, both by 19% more among women than men. Mean serum creatinine increased from 0.87 to 1.17 mg/dL, BUN from 23.7 to 33.1 mg/dL, glucose from 88 to 122 mg/dL, and BMI from 25.9 to 26.6 kg/m2. By multivariate regression, risk factors for declining eGFR ranked: longer lithium treatment, lower lithium dose, higher serum lithium concentration, older age, and medical comorbidity. Later low eGFR was also predicted by lower initial eGFR, and starting lithium at age ≥ 40 years.
LIMITATIONS:
Control data for age-matched subjects not exposed to lithium were lacking.
CONCLUSIONS:
Long-term lithium treatment was associated with gradual decline of renal functioning (eGFR) by about 30% more than that was associated with aging alone. Risk of subnormal eGFR was from 18.1% (≥2 low values) to 29.5% (≥1 low value), requiring about 30 years of exposure. Additional risk factors for low eGFR were higher serum lithium level, longer lithium treatment, lower initial eGFR, and medical comorbidity, as well as older age
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