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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
861

Wind shielding analysis for cold regions using experimental and numerical techniques

Xu, Yizhong January 2016 (has links)
The thesis presents a systematic experimental and numerical study on the interactions among porous fence, airflow, and windblown snowdrifts, a knowledge that will contribute to optimize the performance of porous wind shielding system in Cold Regions. A comprehensive review of the concepts, theories, techniques, and key findings associated with the research work has been undertaken. The key technical parameters influencing fence performance have been systematically studied by means of wind tunnel experimental investigations and Computational Fluid Dynamics (CFD) simulations. The study has found that porosity is the most influential structural parameter affecting the performance of porous fences in many aspects. Fence height stands a significant positive position in terms of its performance. It was found that fence performance is not sensitive to the changes of approaching atmospheric airflow velocity. Nevertheless, a bottom gap can improve snow fence trap efficiency. All of those findings agree with most of the findings of other researchers, which affirms that the research methodology adopted in this research is sound. Physical experimental work was performed to assess the reliability and credibility of the numerical models. Those models have been intentionally simplified, which made them easier to construct and quicker to obtain numerical solutions at a lower computational cost. Furthermore, the numerical models demonstrate the level of competence acquired through this research that is implemented in the optimisation of fence design. Special attention has been paid to the issues where elaborate research work has not been systematically reached in the open literature, this includes areas such as the effects of arrangement of porous holes, fence surface shear, and directions of wind load with respect to the fence, etc. Correlation between the reattachment length, the shelter distance, and the creation and distribution of fence surface shear is reported, to the author's knowledge, for the first time in the open literature. General guidelines for the design of shelters based on porous fences have been established through this study. For example, the desirable size of hole range should be identified beforehand, and porous holes with sharp angular corners should usually be avoided in the fence design. It is recommended to place the fence within an angle of 30° to the wind load, where the effective shelter distance can be estimated in a linearized equation, and the normal drag coefficient can be described as a function of cos2θ. Optimal design of the arrangement of porous holes will maximize the fence performance, especially when the close fence environment is of concern. Although the definition of fence effective zone is still vague in the research field, the key factors influencing the fence effective zone have been investigated by evaluating the reduction of wind velocity leeward of the fence in this thesis. It is found that the fence effective zone is not sensitive to the change of approaching airflow velocity, and that increasing fence height will increase the physical size of the fence effective zone, but not in a proportional manner. It is also concluded that fence effective zone will be significantly reduced when the non-normal wind load is inclined at an angle greater than 30° to the fence. The effective zone increases effectively when the fence porosity is optimal. In contrast to the majority of published research work, the transient snow transport model presented in this work considers the snow transport rate as a whole without distinguishing the rate in saltation and suspension layer. The numerical study indicated that the position of the snow crest is mainly determined by the fence height, while porosity and bottom gap mainly affect the downwind deposition length. The optimal porosity for snow fences is in the range of 0.4 to 0.5, which is greater than the one for wind fences, which lies in the range from 0.25 to 0.35. Two snow crests have been observed leeward the fence at the onset of snow deposition, when the fence was placed without a bottom gap to the snow ground. This finding has not been encountered in any of the reported research work. Wind tunnel simulations of snowdrift around the fences have marginally under-predicted the sizes of snow deposition. The numerical predictions were quantitatively and qualitatively in good agreement with the field observations. This incompetence of wind tunnel experiments on porous fences implies that numerical modelling can play a more important role in snow fence research.
862

The Use of Antibiotics in the Treatment of Skin and Soft Tissue Infections in Selected Canadian First Nations Communities

Jeong, Dahn January 2015 (has links)
Methicillin-resistant Staphylococcus aureus (MRSA) is a growing concern in Canada especially in Aboriginal communities in remote regions. The northern and remote communities possess some or many of the risk factors that are identified in previous research to be associated with Community-Associated Methicillin-resistant Staphylococcus aureus (CA-MRSA) infections such as overcrowding, challenges in maintaining personal hygiene and limited access to healthcare. CA-MRSA spreads rapidly in the communities. It is known to not only affect young and healthy individuals, but it is also associated with high morbidity and mortality rates. Furthermore, antibiotic resistance in CA-MRSA is increasing in Canada. It is known that inappropriate and greater use of antibiotics is associated with increased antibiotic resistance. Resistant CA-MRSA infections are more difficult to treat. To reduce and to control the antibiotic resistance, monitoring the prevalence of CA-MRSA and the changing antibiotic susceptibility profiles at the population level, especially in highly affected communities, is crucial. By monitoring this trend, it will enable healthcare practitioners to provide more adequate and appropriate treatment. To our knowledge, there was no community-based study that examined the epidemiology of CA-MRSA skin and soft-tissue infections (SSTIs) in First Nations communities in Canada at large scale, and the knowledge on the risk factors, outcomes and antibiotic susceptibility profiles is still very limited. This study aimed to describe the local epidemiology of SSTIs at the community level in selected First Nations communities as well as to describe the antibiotic use to treat SSTIs and the antibiotic susceptibility patterns of CA-MRSA. A retrospective chart review was conducted in 12 nursing stations in the First Nations communities across 5 provinces in Canada. The charts of individuals over 18 years of age who had received service at the nursing station in the previous 12 months, starting retrospectively from the date of collection, were reviewed in this study. Each antibiotic prescription that was noted in the chart in this period prior to chart review was recorded in the antibiotic tracking case report form. Data collected included demographics, indication for antibiotic use, antibiotic prescription parameters and patient outcomes. In total, of 372 patient charts reviewed, 224 patient charts contained at least one case (an encounter that resulted in an antibiotic prescription during the study period). Of those 224 charts, 459 cases were recorded and, of those, 137 cases had a diagnosis of an SSTI. In the 65 patients accounting for all cases of SSTI patients, more than 80% of the study population were under the age of 50. The prevalence of impaired renal function was low, diabetes was present in 20% of cases, cardiac disease was present in 15% of cases, and reported alcohol misuse was present in 30% of cases. The presence of indwelling devices was very rare. There were 137 cases of SSTIs over 372 charts reviewed in total. The prevalence of SSTI among the selected First Nations communities in 2012-2013 was estimated at almost 37% (137 cases of SSTIs / 372 charts reviewed). In the 137 SSTI cases, 55 cases were identified as MRSA infections either by laboratory test such as wound culture or by history of colonization documented in the chart. The overall prevalence of MRSA in all SSTI cases was estimated at 40.1% (55 confirmed MRSA positive cases / 137 cases of SSTIs). The majority of SSTIs were purulent infections and wounds. We also found that a wound culture and susceptibility test were performed only in 29% of all SSTI cases. An orally administered antibiotic was most frequently used (in 71.5% of treatments). Topical antibiotics were used in 18.3% and IV antibiotics were used in 8.8%. Other than the antibiotic treatment, wound care was performed in 49% of the SSTI cases and incision and drainage (I&D) procedure in 9%. The majority of MRSA isolates in this study were susceptible to clindamycin and co-trimoxazole (90.5% and 95.2%), but only 29% were susceptible to erythromycin. In general, higher rates of SSTIs were seen in communities where overcrowding and poor access to running water are more prevalent. In this study, we found that the diagnostic tests such as wound culture and sensitivity test was not ordered very often and there was also lack of follow-up or lack of documentation of the follow-up. More research is needed to better understand some of the challenges and risk factors associated with CA-MRSA infections in remote communities. Developing a national-level surveillance system that can help with monitoring the epidemiology of SSTIs and the antibiotic susceptibility test results of CA-MRSA at community level would be essential for better prevention, control, and management. Furthermore, adopting other initiatives such as antibiotic stewardship programs at community and healthcare settings as well as addressing the socio-environmental factors such as housing and access to water would be all very important in the steps to curb antibiotic resistance.
863

Metody vymezování periferních oblastí na území České republiky / Methods of delimitation of peripheral regions in the Czech Republic

Kaňová, Světlana January 2009 (has links)
The diploma thesis is focused on defining the peripheral regions in the Czech Republic. This topic is still very actual, both nationally, and internationally. Study of definition of unexposed regions is a part of comprehensive research of the territory polarization. Concern about this question was intensifying during the nineties. This time was characterized by growing differentiation between regions. This evoked interest about rise and progress of periphery. The theoretical part consists of important concepts, major theoretical approaches, policies and principles, which define the periphery of concern. Also development of interest in the Czech Republic is described as well as situation in foreign countries and time comparison. Practical knowledge of methods in the Czech Republic are summarized in conclusion of the thesis.
864

Statistická analýza kriminality České republiky / Statistical analysis of crime Czech Republic

Kroutilová, Denisa January 2010 (has links)
The crime rate is among the highest risk factors and endangers society. By analyzing the development and subsequent predicting future values, you can take steps that would help to reduce crime and create the conditions conducive to the good development of society and security of citizens. Therefore, the State should control crime by one of the most important priorities. This thesis deals with the analysis of crime and number of people prosecuted in the Czech Republic, constructed using time series. Development into the future is estimated in the next three years. Longer forecast should not make much sense because of the rapidly changing laws. The conclusion is devoted to crime in Czech regions. Analysis is performed using cluster analysis, which examines the number of crimes in different regions. The result is a decision that the region together in terms of crime the most similar.
865

Regionální diferenciace lázeňství v ČR / Regional differences in Czech republic balneology

Vopatová, Tereza January 2013 (has links)
The goal of this thesis is to describe chat is the diference between spa regions around Czech republic with respect to the orientation of the individual spa by health problems and the terms of sevices provided by the spa. The theoretical part describes tourism in genaral from which spatourism is genareted as one of many. The practical part describes individual spa regions of Czech republic and the care which they provide. In every region are listed spas and their characteristics. When rating the individual spas I used as thema in criteria, which I selected, statistical data of the number of spa facilities, number of beds and number of spa visitors. The work then summarizes the differentiations of the spas in the Czech republic which are based on a few selected indicators. The valuation was to determite which region has greater or less or potential then the others.
866

Prostorová koncentrace, specializace a ekonomický růst / Spatial Concentration, Specialization and Economic Growth

Uhlířová, Petra January 2012 (has links)
In various regions, the number of employees working in each sector is different. Some sectors may be in the region employ more workers than other sectors, indicating a higher degree of specialization. In each region, the degree of specialization varies, which could have a direct impact on economic growth. The aim of this study was therefore to investigate the relationship between the degree of specialization and economic growth of the region. It turns out that there is a positive relationship between the degree of specialization and economic growth, which means that the growth rate of specialization will lead to economic growth. It follows that the focus of the region, especially on one sector can lead to faster economic growth.
867

Diffuse radio recombination line emission on the galactic plane

Alves, Marta Isabel Rocha January 2011 (has links)
A full-sky free-free template is increasingly important for the high-sensitivity Cosmic Microwave Background (CMB) experiments, such as Planck. On the Galactic plane, where free-free estimations from Halpha measurements become unreliable, Radio Recombination Lines (RRLs) can be used to determine the thermal brightness temperature unambiguously with no dust contamination. RRLs are a powerful tool for the diagnostic of the interstellar medium, tracing the ionised component, its electron temperature, velocity and radial distributions.This thesis describes the investigation of the ionised emission from HII regions and diffuse gas along the Galactic plane using RRLs, with the aim of providing a map of the free-free emission to complement the high latitude Halpha observations. Measuring the free-free emission on the Galactic plane is of great importance to understand and characterise other Galactic emission components: synchrotron, anomalous dust and thermal dust emission. The fully-sampled HI Parkes All-Sky Survey and associated deep Zone of Avoidance Survey are re-analysed to recover extended RRL emission. They include three RRLs (H166alpha, H167alpha and H168alpha) at frequencies near 1.4 GHz. A data cube covering l=20 degree to 44 degree and |b| < 4 degree is constructed of RRL spectra with velocity and spatial resolution of 20 km/s and 14.8 arcmin, respectively. Well-known HII regions are identified as well as the diffuse RRL emission on the Galactic plane.In order to convert the integrated RRL emission into a free-free brightness temperature a value of the electron temperature (Te) of the ionised gas is needed. Using the continuum and line data from the present survey, the variation of Te with Galactocentric radius was derived for the longitude range l=20 degree to 44 degree, with a mean Te on the Galactic plane of 6000 K. The derived Te variation was used to obtain the first direct measure of the free-free brightness in this region of the Galactic plane. Subtraction of this thermal emission from the total continuum at 1.4 GHz leaves the first direct measurement of the synchrotron emission. A narrow component of width 2 degree is identified in the synchrotron latitude distribution.Determining the free-free and synchrotron emission in this region of the Galactic plane identifies the anomalous microwave component, when combined with WMAP and IRIS data. The results are in agreement with models of small spinning dust grains.
868

Using the auditory steady-state response to diagnose dead regions in the cochlea

Wilding, Timothy January 2011 (has links)
The current behavioural dead region (DR) diagnosis methods such as psychophysical tuning curves and the threshold-equalising noise test require extensive subject co-operation. These present methods cannot be applied to infants. The work presented in the thesis aimed to develop a fast objective DR diagnosis method that could be applied to sleeping hearing-impaired infants. A novel fast objective electrophysiological method of recording response amplitude curves (RACs) which could enable objective DR diagnosis was developed.RACs were derived by recording auditory steady-state response amplitudes using modulated signals in the presence of narrow-band maskers. Two RAC methods were investigated. In the swept method, RACs were recorded in a single test run by recording the response amplitudes across the frequency range of a continuously swept-frequency narrow-band masker. In the fixed method, response amplitudes of eight separate test runs, each in the presence of differing fixed-frequency narrow-band maskers, were recorded.RACs were recorded in normally hearing adult subjects. The results showed that for normally hearing subjects in condition 1 (swept masker), the mean recorded RAC tip for a 2-kHz signal was 2250 Hz and the repeatability coefficient of two repeated recordings in each subject was 389 Hz; in condition 2 (fixed masker), the respective values were 2251 Hz and 342 Hz. These results indicated that the swept masking method is a viable and fast way to record RACs in normally hearing adults.RACs and psychophysical tuning curves (PTCs) were recorded in hearing-impaired adult subjects in order to asses the tip-frequency agreement between the tests. In some cases there were difficulties in using the required signal and masker levels due to maximum sound level limits. The RACs were poorly shaped and had poor repeatability. These findings indicate that the RAC method that was successfully applied to normally hearing subjects requires further development for use with the hearing impaired. The possible causes for the differences in the accuracy of the method between normally hearing and hearing-impaired subjects are discussed. The work presented in this thesis provides the basis upon which further research can be taken forward. It is envisaged that this work, together with further research, will lead to a clinically-effective objective DR diagnosis method.
869

Regionální disparity v uplatnění absolventů vysokých škol na trzích práce v krajích ČR / Regional disparities in the use of graduates in the labor markets in the regions NUTS 3 of the Czech Republic

Michalovská, Zdeňka January 2011 (has links)
This master thesis focuses on the issues of application of the graduates in the labor market. The main objective is to identify and evaluate disparities in the use of graduates in the labor markets in the regions NUTS 3 of the Czech Republic. To fulfill the main objectives and targets have been selected the partial targets namely: the recent development of the quantity of universities and their students from 1989 to the present, the current location of universities in the regions NUTS 3 and the development of graduates over time and according to type of university degree, programs disciplines and gender. The theoretical part is devoted to the definition of basic concepts, application of the relation of education to individuals in the labor market and educational system in the Czech Republic and especially is devoted to tertiary education. The practical part consists of analyzes of trends in the number of graduates from different perspectives andanalyzesthe applicationof universitygraduates,such as the analysis of supply and demand for university graduates and the amount of their income. Because of the result of analysis was possible to identify and evaluate a number of regional differences in the use of graduates in the labor markets in the regions NUTS 3. The differences are formulated at the end of the master thesis.
870

Podnikateľské inkubátory a ich význam pri zvyšovaní konkurencieschopnosti regiónov / Business incubators and their importance in enhancing the competitiveness of regions

Bogyová, Katarína January 2012 (has links)
The diploma thesis focuses on business incubators and the impact they create on the region's competitiveness. The primary purpose of the paper is to analyze the activity of business incubators and to demonstrate, using real examples, positive contribution of their activity on the regional competitiveness. A method, I intend to use, is application of theory covered in theoretical part on my practical part. The basis for analyzing the particular incubator are information collected from the questionnaire survey, structured interviews and documents available.

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