1,694 research outputs found
Initialization Strategy for Nonlinear Systems
The Study Group was asked to provide some hints concerning a choice of initial values to be used for nonlinear algebraic systems. The group has considered the available options and outlined the pros and cons of various methods and provided some recommendations
A Medical Waste Sterilizer
Sterilization of medical waste is very important for the environment, as the exposition may result in various diseases because of viral or bacterial content of the waste. There are devices developed for this purpose aiming to sterilize the waste in a form called batch process, meaning that a certain amount of waste is placed into the system and subjected to a sterilization procedure for a while and removed from the system afterwards. The procedure is repeated by the next set of waste till the whole set is sterilized.
Our aim, however, is to design a device, a rotating cylindrical container having tubular lights attached to the walls inside, through which the waste is exposed to ultraviolet light as it gets rotated and moved towards the exit. The process will continue till the whole set is fed into the system. Such a device would be more effective as compared to batch processing types. The study group is asked to develop a mathematical model to analyse the effect of the number and location of tubes which will lead to maximal exposure during certain amount of time, which also needs an estimate, the sample will reside in the device before it gets discharged
A Tate cohomology sequence for generalized Burnside rings
Cataloged from PDF version of article.We generalize the fundamental theorem for Burnside rings to the mark morphism of plus constructions defined by Boltje. The main observation is the following: If D is a restriction functor for a finite group G, then the mark morphism Ï : D+ â D+ is the same as the norm map of the Tate cohomology sequence (over conjugation algebra for G) after composing with a suitable isomorphism of D+. As a consequence, we obtain an exact sequence of Mackey functors 0 â over(Ext, Ì)Îł- 1 (Ï, D) â D+ over({long rightwards arrow}, Ï) D+ â over(Ext, Ì)Îł0 (Ï, D) â 0 where Ï denotes the restriction algebra and Îł denotes the conjugation algebra for G. Then, we show how one can calculate these Tate groups explicitly using group cohomology and give some applications to integrality conditions. © 2008 Elsevier B.V. All rights reserved
Oxidative Stress and Mitochondrial Dysfunction in Down's Syndrome: Relevance to Aging and Dementia
Genome-wide gene deregulation and oxidative stress appear to be critical factors determining the high variability of phenotypes in Down's syndrome (DS). Even though individuals with trisomy 21 exhibit a higher survival rate compared to other aneuploidies, most of them die in utero or early during postnatal life. While the survivors are currently predicted to live past 60 years, they suffer higher incidence of age-related conditions including Alzheimer's disease (AD). This paper is centered on the mechanisms by which mitochondrial factors and oxidative stress may orchestrate an adaptive response directed to maintain basic cellular functions and survival in DS. In this context, the timing of therapeutic interventions should be carefully considered for the successful treatment of chronic disorders in the DS population
Job Analysis System for Civil Engineers in Construction Companies
Job research and analysis studies are the reports that detail the system andenvironmental conditions and performance of each job for obtaining higher efficiency andreducing the unit cost. In order to do the job analysis properly, information and data regardingthe job have to be evaluated accurately and realistically. The originating point of the article isbased on this definition and requirement. In the study, the established job analysis model hasbeen built on system approach. Steps of the model consist of input-preliminary preparation,process-analysis and conclusion phases.In accordance with the model suggested, a job analysis form has been developed to beused in improvement of functions of various human resources and in selection of civil engineersat manager position of construction companies during the study. The form specifies the jobprofile and personal requirements of civil engineers and gives information about time researchstudies aimed at efficiency. Form data has been collected by interviewing 50 (fifty) civilengineers at manager position working at large and medium sized construction firms, in order tobe used in job analysis discipline. In the study, information and data obtained by job analysisform have been analyzed by statistical methods and the results have been compared to similarliterature findings
Cold Therapy in Migraine Patients: Open-label, Non-controlled, Pilot Study
Some patients with headache report that they have frequently used physical therapies such as application of cold to relieve their headache. There are only a few reported studies related to cold therapies in patients with migraine. In this study, we investigated the effect of cold application on migraine patients. Twenty-eight migraine patients were included. Cold therapy was administered to them by gel cap. Patients used this cap during their two migraine attacks. Before and after the cold therapy, headache severity was recorded by using visual analogue scale (VAS). Patients used this cap for 25 min in each application. They recorded their VAS score just after the therapy and 25 min, 1 h, 2 h and 3 h later. Two patients could not use this therapy due to side effects (one due to cold intolerance and one due to vertigo) in both applications. Therefore, therapeutic efficacy was evaluated in 26 patients. Twenty-five minutes after treatment of the first attack, VAS score was decreased from 7.89 ± 1.93 to 5.54 ± 2.96 (P < 0.01). Twenty-five minutes after treatment of the second attack, VAS score was decreased from 7.7 ± 1.8 to 5.4 ± 3.55 (P < 0.01). Cold application alone may be effective in some patients suffering from migraine attacks. Its combination with conventional drugs should be investigated in future studies
Using Reduced Kinetic Model for the Multi-Objective Optimization of Thermal Section of the Claus Process Leading to a More Cost-Effective and Environmentally Friendly Operation
The Claus process is a sulfur recovery unit wherein hydrogen sulfide is converted into the elemental sulfur. This study aims to model the thermal section of the Claus process, which consists of a reaction furnace and a waste heat boiler, as a configuration of two reactors, and subsequently optimize the entire section. Two different reduced kinetic schemes were provided for both units. Using the validated kinetics, mathematical models were developed. The waste heat boiler was modeled as a plug flow reactor with heat transfer, instead of a heat exchanger. The main objective was to maximize the amount of elemental sulfur at the end of the thermal section. Additionally, maximizing the amount of steam generated in the WHB was considered as a secondary objective, and the multi-objective optimization problem was solved. The sulfur production was improved 14.1% and 30% as a result of single- and multi-objective optimization studies. In addition, as an alternative, the Taguchi method was also used for optimization studies, and optimum values were determined. Using the Taguchi method, we determined that an increase in sulfur production by 24% is possible
Economic burden of ventilator associated pneumonia in a developing country
Ventilator-associated pneumonia (VAP) developed in 96 (60%) of 159 patients with 37.2 cases per 1000 ventilation-days in a medical intensive care unit (MICU). Median time for VAP development was 5.5 days (range: 2-25). The most significant risk factors for VAP were stay in hospital before MICU and length of stay in MICU. The mean length of stay in MICU for VAP patients was 23.8 +/- 19.8 days, which was four-fold higher than for non-VAP patients. The daily cost for VAP patients was half that for non-VAP patients. The total costs for VAP patients were about three-fold higher than for non-VAP patients. (C) 2012 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved
Infrared renormalons and single meson production in proton-proton collisions
In this article, we investigate the contribution of the higher twist Feynman
diagrams to the large- inclusive pion production cross section in
proton-proton collisions and present the general formulae for the higher twist
differential cross sections in the case of the running coupling and frozen
coupling approaches. The structure of infrared renormalon singularities of the
higher twist subprocess cross section and the resummed expression (the Borel
sum) for it are found. We compared the resummed higher twist cross sections
with the ones obtained in the framework of the frozen coupling approximation
and leading twist cross section. We obtain, that ratio for all values of
the transverse momentum of the pion identical equivalent to ratio .
It is shown that the resummed result depends on the choice of the meson wave
functions used in calculation. Phenomenological effects of the obtained results
are discussed.Comment: 28 pages, 13 figure
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