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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.
51

Chicken Eggshell Membrane and Cuticle: Insight from Bioinformatics and Proteomics

Du, Jingwen 10 January 2013 (has links)
The chicken eggshell possesses physical and chemical barriers to protect the embryo from pathogens. The avian eggshell cuticle is the outmost layer of the eggshell whose protein constituents remain largely unknown. Since eggs with incomplete or absent cuticle are more susceptible to bacterial contamination, we hypothesize that cuticle protein components play an important role in microbial resistance. In our study, at least 47 proteins were identified by LC/MS/MS in the non-calcified cuticle layer. Similar to Kunitz-like protease inhibitor (also annotated as ovocalyxin-25, OCX-25) and ovocalyxin-32 (OCX-32) were two of most abundant proteins of the cuticle proteins. Some proteins that have antimicrobial activity were also detected in the proteomic results, such as lysozyme C, ovotransferrin, ovocalyxin-32, cystatin, ovoinhibitor. This study represents the first comprehensive report of the cuticle proteome. Since the sequence similarity of the kunitz motif in OCX-25 is similar to that of BPTI, it is predicted that it will have the same trypsin inhibitory and antimicrobial activity against Gram-positive and/or Gram-negative bacteria. In order to test the antimicrobial property and trypsin inhibitor activity of OCX-25, cuticle proteins were extracted by 1N HCl. Antimicrobial activity was monitored using the Bioscreen C instrument; and antimicrobial activity was identified primarily against Staphylococcus aureus. Trypsin inhibitor activity was studied by using a specific trypsin assay, and the assay indicated that the cuticle proteins could inhibit the reaction of trypsin and substrate. Therefore, the current research has provided some insight into the antimicrobial and enzymatic aspects of the cuticle proteins, and its function for egg protection. Eggshell membranes are another important component of the chicken eggshell.Due to its insoluble and stable properties, there are still many questions regarding formation and constituents of the eggshell membranes. The purpose of our study was to identify eggshell membrane proteins, particularly these responsible for its structural features, by examining the transcriptome of the white isthmus during its formation. Bioinformatics tools were applied to analyze the differentially expressed genes as well as their encoded proteins. Some interesting proteins were encoded by the over-expressed genes in the white isthmus during the formation of eggshell membranes, such as Collagen X, and similar to spore coat protein SP75. These proteins may have potential applications. Our study provides a detailed description of the chicken white isthmus transcriptome during formation of the eggshell membranes; it could lead to develop the strategies to improve food safety of the table egg.
52

A Study on the Embedded Branching Process of a Self-similar Process

Chu, Fang-yu 25 August 2010 (has links)
In this paper, we focus on the goodness of fit test for self-similar property of two well-known processes: the fractional Brownian motion and the fractional autoregressive integrated moving average process. The Hurst parameter of the self-similar process is estimated by the embedding branching process method proposed by Jones and Shen (2004). The goodness of fit test for self-similarity is based on the Pearson chi-square test statistic. We approximate the null distribution of the test statistic by a scaled chi-square distribution to correct the size bias problem of the conventional chi-square distribution. The scale parameter and degrees of freedom of the test statistic are determined via regression method. Simulations are performed to show the finite sample size and power of the proposed test. Empirical applications are conducted for the high frequency financial data and human heart rate data.
53

Expert Finding In Domains With Unclear Topics

Selcuk Dogan, Gonca Hulya 01 February 2012 (has links) (PDF)
Expert finding is an Information Retrieval (IR) task that is used to find the needed experts. To find the needed experts is a noticeable problem in many commercial, educational or governmental organizations. It is highly crucial to find the appropriate experts, when seeking referees for a paper submitted to a conference or when looking for a consultant for a software project. It is also important to find the similar experts in case of the absence or the inability of the selected expert. Traditional expert finding methods are modeled based on three components which are a supporting document collection, a list of candidate experts and a set of pre-defined topics. In reality, most of the time pre-defined topics are not available. In this study, we propose an expert finding system which generates a semantic layer between domains and experts using Latent Dirichlet Allocation (LDA). A traditional expert finding method (voting approach) is used in order to match the domains and the experts as the baseline method. In case similar experts are needed, the system recommends experts matching the qualities of the selected experts. The proposed model is applied to a semi-synthetic data set to prove the concept and it performs better than the baseline method. The proposed model is also applied to the projects of the Technology and Innovation Funding Programs Directorate (TEYDEB) of The Scientific and Technological Research Council of Turkey (T&Uuml / B
54

Relasies in die chaosteorie / Leon Smuts

Smuts, Leon January 2005 (has links)
The central purpose of this study is the integration of modem philosophical thinking with different chaos theory principles and definitions to form relational perspectives. Relations are used in different contexts to base the causes of deterministic chaos (chaost) in the laws of nature which constitutes order. The chaost-attractor is used as subjective conception to investigate the possibilities of hidden order in a seemingly chaotic state of the objective reality. Relevant definitions of the chaos theory were analysed methodically and transcendentally with the aid of concepts of order and relations. Attention is given to the broad associations and analogies from philosophy and other disciplines which relate to the connectivity of objects to form systems. Subjective model development was done which is used to consequentially analyse some statements from published research which applied principles of chaost. It is argued that: the intrinsic properties of objects determine the causality of forces which bind objects to compose systems; a web of interactive bonds functions subjective to laws of nature which determine whether a system is in a state of order, chaost or real chaos; a dynamical transfer of many intrinsic and asymmetric properties via internal bonds constitutes non-linear connectivity which causes a sensitivity for initial conditions. It is found that the chaost of the chaos theory is not the same as real, objective chaos. The random-like evolution of a dynamic system is determined by the occurrence of irregularities and uncertainties in its internal order. A web of interactive bonds distribute small changes self-similar and scale-relevant. The difficulty in describing and explaining the complex behaviour of composed entities is simplified by the proposed web-chaost model. / Thesis (M.A. (Philosophy))--North-West University, Potchefstroom Campus, 2006.
55

Presentations and Structural Properties of Self-similar Groups and Groups without Free Sub-semigroups

Benli, Mustafa G 16 December 2013 (has links)
This dissertation is devoted to the study of self-similar groups and related topics. It consists of three parts. The first part is devoted to the study of examples of finitely generated amenable groups for which every finitely presented cover contains non-abelian free subgroups. The study of these examples was motivated by natural questions about finiteness properties of finitely generated groups. We show that many examples of amenable self-similar groups studied in the literature cannot be covered by finitely presented amenable groups. We investigate the class of contracting self-similar groups from this perspective and formulate a general result which is used to detect this property. As an application we show that almost all known examples of groups of intermediate growth cannot be covered by finitely presented amenable groups. The latter is related to the problem of the existence of finitely presented groups of intermediate growth. The second part focuses on the study of one important example of a self-similar group called the first Grigorchuk group G, from the viewpoint of pro finite groups. We investigate finite quotients of this group related to presentations and group (co)homology. As an outcome of this investigation we prove that the pro finite completion G_hat of this group is not finitely presented as a pro finite group. The last part focuses on a class of recursive group presentations known as L-presentations, which appear in the study of self-similar groups. We investigate the relation of such presentations with the normal subgroup structure of finitely presented groups and show that normal subgroups with finite cyclic quotient of finitely presented groups have such presentations. We apply this result to finitely presented indicable groups without free sub-semigroups.
56

Relasies in die chaosteorie / Leon Smuts

Smuts, Leon January 2005 (has links)
The central purpose of this study is the integration of modem philosophical thinking with different chaos theory principles and definitions to form relational perspectives. Relations are used in different contexts to base the causes of deterministic chaos (chaost) in the laws of nature which constitutes order. The chaost-attractor is used as subjective conception to investigate the possibilities of hidden order in a seemingly chaotic state of the objective reality. Relevant definitions of the chaos theory were analysed methodically and transcendentally with the aid of concepts of order and relations. Attention is given to the broad associations and analogies from philosophy and other disciplines which relate to the connectivity of objects to form systems. Subjective model development was done which is used to consequentially analyse some statements from published research which applied principles of chaost. It is argued that: the intrinsic properties of objects determine the causality of forces which bind objects to compose systems; a web of interactive bonds functions subjective to laws of nature which determine whether a system is in a state of order, chaost or real chaos; a dynamical transfer of many intrinsic and asymmetric properties via internal bonds constitutes non-linear connectivity which causes a sensitivity for initial conditions. It is found that the chaost of the chaos theory is not the same as real, objective chaos. The random-like evolution of a dynamic system is determined by the occurrence of irregularities and uncertainties in its internal order. A web of interactive bonds distribute small changes self-similar and scale-relevant. The difficulty in describing and explaining the complex behaviour of composed entities is simplified by the proposed web-chaost model. / Thesis (M.A. (Philosophy))--North-West University, Potchefstroom Campus, 2006.
57

Chicken Eggshell Membrane and Cuticle: Insight from Bioinformatics and Proteomics

Du, Jingwen 10 January 2013 (has links)
The chicken eggshell possesses physical and chemical barriers to protect the embryo from pathogens. The avian eggshell cuticle is the outmost layer of the eggshell whose protein constituents remain largely unknown. Since eggs with incomplete or absent cuticle are more susceptible to bacterial contamination, we hypothesize that cuticle protein components play an important role in microbial resistance. In our study, at least 47 proteins were identified by LC/MS/MS in the non-calcified cuticle layer. Similar to Kunitz-like protease inhibitor (also annotated as ovocalyxin-25, OCX-25) and ovocalyxin-32 (OCX-32) were two of most abundant proteins of the cuticle proteins. Some proteins that have antimicrobial activity were also detected in the proteomic results, such as lysozyme C, ovotransferrin, ovocalyxin-32, cystatin, ovoinhibitor. This study represents the first comprehensive report of the cuticle proteome. Since the sequence similarity of the kunitz motif in OCX-25 is similar to that of BPTI, it is predicted that it will have the same trypsin inhibitory and antimicrobial activity against Gram-positive and/or Gram-negative bacteria. In order to test the antimicrobial property and trypsin inhibitor activity of OCX-25, cuticle proteins were extracted by 1N HCl. Antimicrobial activity was monitored using the Bioscreen C instrument; and antimicrobial activity was identified primarily against Staphylococcus aureus. Trypsin inhibitor activity was studied by using a specific trypsin assay, and the assay indicated that the cuticle proteins could inhibit the reaction of trypsin and substrate. Therefore, the current research has provided some insight into the antimicrobial and enzymatic aspects of the cuticle proteins, and its function for egg protection. Eggshell membranes are another important component of the chicken eggshell.Due to its insoluble and stable properties, there are still many questions regarding formation and constituents of the eggshell membranes. The purpose of our study was to identify eggshell membrane proteins, particularly these responsible for its structural features, by examining the transcriptome of the white isthmus during its formation. Bioinformatics tools were applied to analyze the differentially expressed genes as well as their encoded proteins. Some interesting proteins were encoded by the over-expressed genes in the white isthmus during the formation of eggshell membranes, such as Collagen X, and similar to spore coat protein SP75. These proteins may have potential applications. Our study provides a detailed description of the chicken white isthmus transcriptome during formation of the eggshell membranes; it could lead to develop the strategies to improve food safety of the table egg.
58

Propriedades e convergência de certas fórmulas de quadratura interpolatórias

Veronese, Daniel Oliveira [UNESP] 24 February 2005 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:26:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-02-24Bitstream added on 2014-06-13T18:30:55Z : No. of bitstreams: 1 veronese_do_me_sjrp.pdf: 430710 bytes, checksum: 769cae2276392992bc8f2c9eaf54fd4e (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Dentre as diversas fórmulas de quadratura interpolatórias estão aquelas que utilizam em sua construção as propriedades dos polinômios ortogonais Pn, ou ainda dos polinômios similares Bn. Consideramos, aqui, fþormulas de quadratura envolvendo polinôomios em x da forma .n(x, .) = Pn-1(.)Pn(x) - Pn(.)Pn-1(x), e da forma Gn(x, u) = Bn-1(u)Bn(x) - Bn(u)Bn-1(x). Abordamos ainda certas fþormulas de quadratura que visam aproximar a integral de um produto de duas funções k e f sendo k Lebesgue integrþavel e f Riemann integrþavel. O principal objetivo deste trabalho þe analisar propriedades das fþormulas de quadratura utilizando-se .n e obter propriedades anþalogas para o caso onde utiliza-se Gn, bem como estudar o erro e as propriedades de convergência das fórmulas envolvendo k e f. Propriedades dos pesos das fórmulas de quadratura nos diversos casos são analisadas, a convergência das fórmulas associadas a k e f são estudadas mediante determinadas escolhas de pontos. / Among the many well known quadrature formulas one finds those interesting interpolatory quadrature formulas that take advantage of the properties of orthogonal polynomials Pn or similar polynomials Bn. Here, we consider the interpolatory quadrature rules based on the zeros of the polynomials øn(x, î) = Pn.1(î)Pn(x).Pn(î)Pn.1(x), and Gn(x, u) = Bn.1(u)Bn(x) . Bn(u)Bn.1(x) where î and u are arbitrary parameters. One of the objective of this dissertation is to study some of the known properties of quadrature rules based on øn(x, î) and consider the analogous properties of the quadrature rules based on Gn(x, u).We also look at the convergence properties of those quadrature rules that serve to approximate integrals of the product of functions k and f, where k is a Lebesgue integrable function and f needs to be a Riemann integrable function.
59

En realistisk migrationspolitik för en ny tid? : En komparativ studie om migrationspolitik inom Socialdemokraterna i Sverige och Danmark

Melander, Jenny January 2018 (has links)
This essay has examined the social-democratic parties in both Sweden and Denmark and their political development regarding immigration policy during the period 2014-2018. This period saw a large number of refugees who came to Europe, which led to stricter immigration policy across Europe. The Danish migration policy has been stricter than the Swedish migration policy. Denmark is therefore interesting to compare with Sweden because they are a country similar to Sweden in many ways. The questions in this essay is following: - How has the Social Democrats migration policy evolved in Sweden compared to Denmark from 2014 to 2018? - How can these parties' migration policy be explained? The questions are answered by comparing the Social Democrats in Sweden and the Social Democrats in Denmark, which has been done according to the model Most Similar System Design (MSSD) with the control variables historical background, ideological, financial situation and political system. The explanatory variable is political culture and the dependent variable is a migration policy. The empirical material has then been compared in accordance with MSSD and opposed the theory othering. The conclusions of this essay are based on the fact that migration policy is different due to political culture.
60

Probabilistic and statistical problems related to long-range dependence

Bai, Shuyang 11 August 2016 (has links)
The thesis is made up of a number of studies involving long-range dependence (LRD), that is, a slow power-law decay in the temporal correlation of stochastic models. Such a phenomenon has been frequently observed in practice. The models with LRD often yield non-standard probabilistic and statistical results. The thesis includes in particular the following topics: Multivariate limit theorems. We consider a vector made of stationary sequences, some components of which have LRD, while the others do not. We show that the joint scaling limits of the vector exhibit an asymptotic independence property. Non-central limit theorems. We introduce new classes of stationary models with LRD through Volterra-type nonlinear filters of white noise. The scaling limits of the sum lead to a rich class of non-Gaussian stochastic processes defined by multiple stochastic integrals. Limit theorems for quadratic forms. We consider continuous-time quadratic forms involving continuous-time linear processes with LRD. We show that the scaling limit of such quadratic forms depends on both the strength of LRD and the decaying rate of the quadratic coefficient. Behavior of the generalized Rosenblatt process. The generalized Rosenblatt process arises from scaling limits under LRD. We study the behavior of this process as its two critical parameters approach the boundaries of the defining region. Inference using self-normalization and resampling. We introduce a procedure called "self-normalized block sampling" for the inference of the mean of stationary time series. It provides a unified approach to time series with or without LRD, as well as with or without heavy tails. The asymptotic validity of the procedure is established.

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