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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.
21

Effects of sequential Campylobacter jejuni 81-176 lipooligosaccharide core truncations on stress survival and pathogenesis

Naito, Mizue 11 1900 (has links)
Campylobacterjejuni, a Gram-negative enteric pathogen, is the leading cause of bacterial gastroenteritis in the developed world. A C. jejuni strain 8 1-176 transposon library was used to screen for mutants over-producing a calcofluor white (CFW)-reactive polymer implicated in biofilm formation. This identified two lipooligosaccharide (LOS) core mutants: one defective for a two-domain glycosyltransferase (lgtF), and the other defective in a heptosyltransferase (waaF). To determine if other LOS core mutants displayed a similar phenotype, and to explore other biological outcomes of step-wise LOS truncations on C. jejuni stress resistance and pathogenesis, mutant strains defective for GaiT and CstII were also constructed. Silver stain and mass spectrometry analyses confirmed the sequential truncation of sialic acid (ΔcstII), galactose (ΔgalT), two glucoses (ΔlgtF), and heptose II (ΔwaaF). While the ΔlgtF and ΔwaaF mutants exhibited enhanced biofilm formation and ΔlgtF displayed increased sensitivity to complement killing, no effect for these phenotypes and only modest alterations in CFW reactivity were seen with partial outer core truncations. Deletion of LgtF had no effect on mouse colonization in vivo, or on invasion and intracellular survival in epithelial cells in vitro. In contrast, the ΔwaaF mutant exhibited a significant defect in intracellular survival in vitro. Interestingly, the mutants exhibited stepwise increases in susceptibility to the antimicrobial peptide LL-37, with /waaF and ΔlgtF being more susceptible and ΔgalT and ΔstII being more resistant than wild type. In contrast, all of the mutants were highly susceptible to polymyxin B. This is the first report of C. jejuni susceptibility to LL-37 and of LOS affecting polymyxin B resistance. Each of these appears to be independent of overt effects on outer membrane protein expression, membrane stability, or surface hydrophobicity. Together, our data indicate that the length and specific moieties of the LOS play important roles in C. jejuni biology, and suggest a dynamic interplay of the LOS with other stress resistance factors.
22

The Translation of Core Values in a Multinational Organisation : H&M in Shanghai - A Case Study

Gustafsson, Nathalie, Sylvan, Charlotta January 2013 (has links)
The thesis addresses the translation process of organisational core values. Core values can be seen as the guiding principles that reveal how the organisation conducts its business. These are often written down as a part of the company’s philosophy and tend to be explicitly articulated to all their entities and functions throughout their organisation. By doing so, the organisation wish to benchmark certain behaviour among their employees. In this thesis, the purpose is to explore how the employees in a subsidiary translate and understand the core values of their Swedish employer. Our aim is to investigate what happens with the meaning of the core values when translated by the employees, as well as to see how these values are visible in the employees day-to-day actions. In this study, a qualitative approach have been used and a case study has been conducted in one of H&M’s subsidiaries. Through 12 semi-structured interviews with employees with different roles in the organisation we have been able to create further understanding of the phenomenon of core value translation in a Chinese setting. H&M is a large, multinational retail company with presence in 49 countries all over the world. This case study can serve the purpose guide managers wanting to understand how their Chinese colleagues accept and interpret their strategies, as more and more Swedish companies are expanding to China. The nature of the study is of abductive character, where we have used the ‘systematic combining’ approach. This enabled us to incorporate new theories and data throughout the research process to facilitate our understanding of our findings. The theoretical background has thus served as base for our understanding and have been constantly reviewed and revised during the research process. Our conclusion from this study is that the translation of the core values relies on the institutionalised organisational procedures and processes set in place. What supported the translation process were mainly the daily conversations with fellow colleagues and repeated procedures, such as meetings and interaction between positions. We also found that those values that had a clear practical usage, tended to be easier for the employees to translate into own actions. Our main finding is however, that the employees translated the core values into a guiding tool that supported and joined the workforce in their daily activities. All parts of the value ‘package’ had been re-contextualised to fit the employees in their local context and were visible in their actions in various ways, but with the common purpose to guide.
23

Assessment of A Training Program for Medical Students on The Improvement of Clinical Skills and Management of Outpatients

Fang, Yi-ping 18 August 2010 (has links)
Objectives¡GThe purposes of this study were to understand the circumstance of the learner about ambulatory care education and to realize the demand and attitudes of learning from the medical students, meanwhile to explore the effectiveness after receiving this education. Besides, this study is also combined with the six core competencies as principles to find out the attitudes of the education from the medical students and the factors of upgrading their clinical skills. Methods¡GThis cross-sectional study employed quantitative method to conduct the research, and this population included medical students from a medical canter of the southern of Taiwan. Structured questionnaires were conducted to medical students, a total of 78 uestionnaires were distributed with 67 questionnaires being returned.The data is analyzed by SPSS 12.0 and used descriptive statistics, factor analysis, t-test, and ANOVA, correlation analysis, and multiple regression analysis. Results¡GThe major findings were as following¡G The results of this study show that most of the time, the medical students participated 1 to 2 times per month, and they also considered the implementation of 2 times one month is appropriate.The medical students also thought that the most ideal number of patient are three, and the result also showed that there were 36¡]53¢H¡^ persons encountered three patients. Besides, the method which the students met was the medical student conducted diagnosis the patients first, and the teacher taught the students then. And there were 52¡]77.6¢H¡^ persons encountered this situation. The study found that the six core competences applied to the ambulatory care education will be classified into three abilities were¡¨ basic medical expertise¡¨¡B¡¨advanced medical diagnostic skills¡¨and¡¨medical knowledge of professional application¡¨. And the result also showed that after ambulatory care training, the basic medical expertise benefited best to the students, and then was the advanced medical diagnosis and medical knowledge of professional application.The study found that the best benefits of clinical competence of medical students was "history taking" followed by "physical and special inspection" and "clinical diagnostic ability", the lowest score was "the administrative processes". And these three abilities were in compliance with the results of clinical ability from this study which pointed to the ¡§basic medical expertise¡¨. It can be found that the goal of the ambulatory care education for the medical student was aimed to the basic medical ability, this result of the research was matched with the direct and discontinuous properties of the outpatient clinic. Conclusion¡GThe study found that the most beneficial factors which could enhance the students the overall clinical skills are the frequency of participating ambulatory care education and the attitudes and enthusiasm of the teaching physicians. If we could measure the demand of involving in the ambulatory care education from the trainee, we could effectively distinguish from the clinical operations and clinical teaching schedule, in this way, it will make the system of ambulatory care education perfect. In addition, the guidance of teachers such as the enthusiasm¡Bcommunication skills¡Bfriendly attitude¡Bteaching ability and the other personal characteristics will affect the effectiveness of the implementation of ambulatory care education. It was recommended to strengthen the capacity of training instructors about teaching, the manager could regularly organize various workshops, seminars, case report, continuous education to train the enthusiastic teaching physician and made them have the teaching skills of instructors in order to enhance the effectiveness of the ambulatory care education.
24

The Hierarchical Core-Based Multicast Routing Protocol in Wireless Ad Hoc Networks

Lan, Yin-Ming 29 June 2003 (has links)
Wireless Ad hoc Network is a self-organizing network. It consists of many mobile nodes and it is a dynamic topology network. It is an impermanent wireless network. It is not an infrastructure-based network, and can be deployed in a short time. Therefore, it can be highly used in some emergency situations, such as, in emergency rescue actions, in military ¡Ketc. As a result, multicast plays an important role here. But before putting it into applications, we have to consider some problems such as scalability, control overhead, data delivery ratio, and routing delay. Some approaches we have learned can¡¦t resolve these problems. So, here we propose a new multicast routing protocol. It¡¦s a kind of core-based multicast protocols. First, we divide whole network into several sub-networks called as cluster, and pick up a node as the cluster core node from each cluster, and this cluster core node will manage all member nodes in this area. All cluster core nodes will connect to each other. Source node in each cluster will send messages to the it¡¦s cluster core-node and then the cluster core node will forward this message to other cluster core-nodes. Finally, the messages will be sent to the destination, member nodes of a multicast session. In this multicast routing protocol, we reduce control packets by localization and lower control overhead. With localization, every nodes only have information from near-by nodes, and this reduce the delay time of routing effectively. More, localization does not increase too much nodes when a message travels from A to B and raise the data delivery ratio. And because of localization, whole network is scalability.
25

Core-scale heterogeneity and dual-permeability pore structure in the Barnett Shale

Cronin, Michael Brett 02 February 2015 (has links)
I present a stratigraphically layered dual-permeability model composed of thin, alternating, high (~9.2 x 10⁻²⁰ m²) and low (~3.0 x 10⁻²² m²) permeability layers to explain pressure dissipation observed during pulse-decay permeability testing on an intact Barnett Shale core. I combine both layer parallel and layer perpendicular measurements to estimate layer permeability and layer porosity. Micro-computed x-ray tomography and scanning electron microscopy confirm the presence of alternating cm-scale layers of silty-claystone and organic-rich claystone. I interpret that the silty-claystone has a permeability of 9.2 x 10⁻²⁰ m² (92 NanoDarcies) and a porosity of 1.4% and that the organic-rich claystone has a permeability of 3.0 x 10⁻²² m² (0.3 NanoDarcies) and a porosity of 14%. A layered architecture explains the horizontal (k [subscript H] = 107 x 10⁻²¹ m²) to vertical (k [subscript V] = 2.3 x 10⁻²¹ m²) permeability anisotropy ratio observed in the Barnett Shale. These core-scale results suggest that spacing between high-permeability carrier beds can influence resource recovery in shales at the reservoir-scale. I also illustrate the characteristic pulse-decay behavior of core samples with multiple mutually-orthogonal fracture planes, ranging from a single planar fracture to the Warren and Root (1963) "sugar cube" model with three mutually-orthogonal fracture sets. By relating sub core-scale matrix heterogeneity to core-scale gas transport, this work is a step towards upscaling experimental permeability results to describe in-situ gas flow through matrix at the reservoir scale. / text
26

A body wave study of the seismic velocity and attenuation structures of Earth's inner core

Waszek, Lauren Esme January 2012 (has links)
No description available.
27

Normal mode and body wave studies of the Earth's inner core

Mäkinen, Anna Marjatta January 2013 (has links)
No description available.
28

Effects of sequential Campylobacter jejuni 81-176 lipooligosaccharide core truncations on stress survival and pathogenesis

Naito, Mizue 11 1900 (has links)
Campylobacterjejuni, a Gram-negative enteric pathogen, is the leading cause of bacterial gastroenteritis in the developed world. A C. jejuni strain 8 1-176 transposon library was used to screen for mutants over-producing a calcofluor white (CFW)-reactive polymer implicated in biofilm formation. This identified two lipooligosaccharide (LOS) core mutants: one defective for a two-domain glycosyltransferase (lgtF), and the other defective in a heptosyltransferase (waaF). To determine if other LOS core mutants displayed a similar phenotype, and to explore other biological outcomes of step-wise LOS truncations on C. jejuni stress resistance and pathogenesis, mutant strains defective for GaiT and CstII were also constructed. Silver stain and mass spectrometry analyses confirmed the sequential truncation of sialic acid (ΔcstII), galactose (ΔgalT), two glucoses (ΔlgtF), and heptose II (ΔwaaF). While the ΔlgtF and ΔwaaF mutants exhibited enhanced biofilm formation and ΔlgtF displayed increased sensitivity to complement killing, no effect for these phenotypes and only modest alterations in CFW reactivity were seen with partial outer core truncations. Deletion of LgtF had no effect on mouse colonization in vivo, or on invasion and intracellular survival in epithelial cells in vitro. In contrast, the ΔwaaF mutant exhibited a significant defect in intracellular survival in vitro. Interestingly, the mutants exhibited stepwise increases in susceptibility to the antimicrobial peptide LL-37, with /waaF and ΔlgtF being more susceptible and ΔgalT and ΔstII being more resistant than wild type. In contrast, all of the mutants were highly susceptible to polymyxin B. This is the first report of C. jejuni susceptibility to LL-37 and of LOS affecting polymyxin B resistance. Each of these appears to be independent of overt effects on outer membrane protein expression, membrane stability, or surface hydrophobicity. Together, our data indicate that the length and specific moieties of the LOS play important roles in C. jejuni biology, and suggest a dynamic interplay of the LOS with other stress resistance factors.
29

Efficient use of Multi-core Technology in Interactive Desktop Applications

Karlsson, Johan January 2015 (has links)
The emergence of multi-core processors has successfully ended the era where applications could enjoy free and regular performance improvements without source code modifications. This thesis aims to gather experiences from the work of retrofitting parallelism into a desktop application originally written for sequential execution. The main contribution is the underlying theory and the performance evaluation, experiments and tests of the parallel software regions compared to its sequential counterparts. The feasibility is demonstrated as the theory is put into use when a complex commercially active desktop application is being rewritten to support parallelism. The thesis finds no simple guaranteed solution to the problem of making a serial application execute in parallel. However, experiments and tests proves that many of the evaluated methods offers tangible performance advantages compared to sequential execution.
30

Simulation of hydrocyclone performance using 3D computational fluid dynamics

Cullivan, James Christian January 2002 (has links)
No description available.

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