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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.
101

Astrocyte and oligodendrocyte dynamics in central pontine myelinolysis

Löber-Handwerker, Ronja 12 July 2022 (has links)
Introduction: Astrocytopathy is known to be an early feature of different neuroinflammatory diseases. However, the impact of astrocyte loss and repopulation on the development and progression of demyelinating lesions in complex etiologies, such as multiple sclerosis, is difficult to determine. To more easily analyse astrocyte- oligodendrocyte-interactions during lesion formation and progression in the human brain, diseases like Central pontine myelinolysis (CPM) can be used as a less complex model of demyelinating disorders. CPM is a rare neurological condition characterized by damage to the myelin sheath of pontine nerves after osmotic shifts in serum. Astrocytopathy is regarded to be the first event in the pathogenesis of CPM lesions. Methods: Histological investigation of autopsy tissue from human CPM patients was performed. Lesions were staged considering the myelination and the appearance of different astrocyte subtypes, which was used to judge behaviour of the astrocytic compartment. Further, dynamics of oligodendrocyte loss and repopulation were analysed and compared to the astrocytic repopulation. Results: Early-staged lesions were largely demyelinated and showed an overall reduction of astrocyte densities. The few astrocytes present showed a bipolar morphology and were APQ4-negative, indicating an immature state. Intermediate- stage lesions were still largely demyelinated, but had increased overall densities of astrocytes, which did not yet reflect densities observed in the perilesion. Astrocytes appeared mostly ramified and AQP4-positive, indicating maturity. Nevertheless, bipolar astrocytes were still observable, indicating that repopulation was not yet finalized. Late-stage CPM-lesions were at least partially remyelinated. Astrocytes were detectable in overall densities comparable to the perilesion and showed a ramified (or even reactive morphology), as well as regular expression of AQP4. Investigating the oligodendrocytes, intralesional densities were reduced in early- and intermediate-stage lesions when compared to the perilesion. Re-increase in oligodendrocyte densities was first observable in late-stage lesions, but did not reach perilesional levels. Conclusion: The study at hand indicates that the recovery of demyelinated osmolyte- induced pontine lesions follows a distinct time-course. Repopulation of the lesion with oligodendrocytes is not carried out until lesions are completely repopulated with functional resident astrocytes, as indicated by the ramified morphology and the expression of AQP4. Further studies will be needed to determine, whether the appearance of immature astrocytes, indicating an ongoing repopulation of lesions with astrocytes, correlates with an inefficient repair of demyelinated lesions.:List of Abbreviations.................................................................................................................6 1 Introduction................................................................................................................7 1.1 Osmotic Demyelinating Syndrome......................................................................... 7 1.2 Clinical manifestation............................................................................................. 9 1.3 Diagnosis and Management of CPM.....................................................................11 1.4 Aetiology of Central Pontine Myelinolysis.................................. ......................... 14 1.5 The brain, its adaptation to hyponatraemia and response to correction – pathophysiology of CPM............................................................................................16 1.6 Pathology of myelin............................................................................................. 19 1.6.1 Astrocytopathy and oligodendrocytopathy.................................................................................................20 1.7 Aims of the study................................................................................................. 23 2 Material und Methods............................................................................................. 24 2.1 Patient tissue........................................................................................................ 24 2.2 Histology and immunohistochemistry................................................................................................24 2.2.1 Basic concepts........................................................................................... ......24 2.2.2 Hematoxylin and Eosin (HE)............................................................................. 26 2.2.3 Luxol Fast Blue/ Periodic Acid Schiff stain........................................................27 2.2.4 Immunohistochemistry. Application and Protocol.............................................28 2.3 Implementation.................................................................................................... 31 2.4 Estimation of demyelination................................................................................. 32 2.5 Analysis of cell density and proliferation.............................................................. 32 2.6 Data plotting and statistical analysis.................................................................... 32 3 Results..................................................................................................................... 33 3.1 Patient cohort....................................................................................................... 33 3.2 Characteristics of demyelination.......................................................................... 35 3.3 CPM lesion and disease staging.......................................................................... 37 3.4 Astrocytes within human CPM lesions................................................................. 42 3.4.1 Astrocyte densities are decreased in early CPM lesions....................................42 3.4.2 Astrocytes in CPM– morphological distinctions.................................................45 3.5 Oligodendrocyte densities within human CPM lesions.........................................48 3.6 Macrophages and activated microglia.................................................................. 54 3.6.1 KiM1P – a marker for infiltrating macrophages and activated microglia............54 3.6.2 Proliferating Iba1+ cells are observed in all lesion stages..................................58 4 Discussion................................................................................................................ 61 4.1 Lesion Staging...................................................................................................... 61 4.2 Astrocytes in the pathogenesis of CPM............................................................... 65 4.3 Oligodendrocyte pathology in CPM..................................................................... 69 4.4 Mechanisms of regeneration in human CPM lesions............................................72 4.5 Summary, interpretation and limitations of our study............................................78 5 Conclusion and Outlook.......................................................................................... 80 6 Bibliography............................................................................................................. 82 7 List of Tables.............................................................................................................91 8 List of Figures.......................................................................................................... 92 9 Appendix.................................................................................................................. 94 9.1 Declaration of Authenticity.....................................................................................94 9.2 Acknowledgements...............................................................................................95
102

Study of continuous-phase four-state modulation for cordless telecommunications. Assessment by simulation of CP-QFSK as an alternative modulation scheme for TDMA digital cordless telecommunications systems operating in indoor applications

Bomhara, Mohamed A. January 2010 (has links)
One of the major driving elements behind the explosive boom in wireless revolution is the advances in the field of modulation which plays a fundamental role in any communication system, and especially in cellular radio systems. Hence, the elaborate choice of an efficient modulation scheme is of paramount importance in the design and employment of any communications system. Work presented in this thesis is an investigation (study) of the feasibility of whether multilevel FSK modulation scheme would provide a viable alternative modem that can be employed in TDMA cordless communications systems. In the thesis the design and performance analysis of a non-coherent multi-level modem that offers a great deal of bandwidth efficiency and hardware simplicity is studied in detail. Simulation results demonstrate that 2RC pre-modulation filter pulse shaping with a modulation index of 0.3, and pre-detection filter normalized equivalent noise bandwidth of 1.5 are optimum system parameter values. Results reported in chapter 5 signify that an adjacent channel rejection factor of around 40 dB has been achieved at channel spacing of 1.5 times the symbol rate while the DECT system standards stipulated a much lower rejection limit criterion (25-30dB), implying that CP-QFSK modulation out-performs the conventional GMSK as it causes significantly less ACI, thus it is more spectrally efficient in a multi-channel system. However, measured system performance in terms of BER indicates that this system does not coexist well with other interferers as at delay spreads between 100ns to 200ns, which are commonly encountered in such indoor environment, a severe degradation in system performance apparently caused by multi-path fading has been noticed, and there exists a noise floor of about 40 dB, i.e. high irreducible error rate of less than 5.10-3. Implementing MRC diversity combiner and BCH codec has brought in a good gain. / Higher Education Ministry
103

Konsten att fusionera i kommunikationsbranschen

Ekelund, Jakob January 2016 (has links)
Den här studien undersöker sammanslagning som expansions- och överlevnadsmetod förkommunikationsbyråer, där även kundernas perspektiv tas i beaktande. Studien syftar till attundersöka huruvida en sammanslagning är en lämplig expansionsmetod ikommunikationsbranschen, och hur genomförandet påverkar kundportföljen, samt hurkundernas upplevelse av byrån utvecklas som följd. Det är en fallstudie som fokuserar på ensammanslagning mellan byråerna First Flight och Wonderleap & Eight, som genomfördes ijanuari 2015 och resulterade i FEW Agency. Studien baseras dels på kvalitativa intervjuer med representanter från FEW Agency, och dels på en enkätundersökning med företagets kunder. Studiens övergripande perspektiv är trots kvantitativa inslag kvalitativt. En sammanslagning av det här slaget bekräftas som en lyckosam expansionsmetod för att uppnå en bättre balans i kundportföljen och för att attrahera fler och större kunder. Metoden kan även vara en konstruktiv strategi för att bevara de befintliga kunderna. En alternativ CPM-modell presenteras, som kan vara till hjälp för att kategorisera kunderna och kunna ta informerade strategiska beslut kring kundportföljen. Kunderna upplever den sammanslagna verksamhetens kreativa och kvalitetsmässiga kompetens samt erbjudandet bättre än före sammanslagningen. Däremot har relationskvaliteten mellan byrån och kunderna tagit vis skada av sammanslagningen. / This study examines merger as an expansion method for small to medium-sized communication agencies, in order to survive as a business. The client perspective is also taken into consideration and their perception of such a merger is studied. The purpose is to examine whether a merger is a suitable method for expansion in the communication business, and how it affects the customer portfolio, and how the client’s perception of the collaboration develops as a result. It is a case study focusing on a recently completed merger (Jan- 15) between the agencies First Flight and Wonderleap & Eight, resulting in the new agency FEW Agency. The study uses a mixed-method incorporating qualitative and quantitative elements in the client-agency context, although the main perspective of the study is qualitative. First, interviews were made with the merging agency, and secondly, a survey was used to adopt the client perspective of the merger. Merger is confirmed to be a successful method for expansion in order to provide a better balance in the customer portfolio and to gain more and bigger clients. Merger also shows to be a constructive and proactive method for client retention. An alternative CPM-model is also presented, which can be used to categorize the clients and furthermore as a foundation for making informed and strategic decisions regarding the customer portfolio. The clients perceive the merged business better in aspects of creativity, quality and the width of services than before the merger. But the relationship quality seems to have taken some damage.
104

A Resource-constrained CPM (RCPM) Scheduling and Control Technique with Multiple Calendars

Kim, Kyunghwan 04 August 2003 (has links)
This research presents a Resource-constrained Critical Path Method (RCPM) technique that capitalizes on and improves the existing Critical Path Method (CPM) and Resource-Constrained Scheduling (RCS) techniques. A traditional CPM schedule is not realistic since it assumes unlimited resources, some of which are highly limited in practice. Although traditional RCS techniques can consider resource limitations, they do not provide correct floats and the critical path as the CPM does. The difference between the theoretical remaining total float and the real remaining total float is referred to as "Phantom Float" in this study. Another disadvantage of the traditional RCS techniques is that work sequence in the schedule could be considerably changed with a schedule update resulting in high costs to reorganize it. These problems are caused by the fact that, in addition to technological relationships, a resource-constrained schedule contains resource dependencies between activities that are neglected in traditional RCS techniques. This study proposes a step-by-step RCPM algorithm to consider those resource-constrained relationships. Hence, the method can identify real floats and correct critical paths, considering both technological and resource-dependent relationships. RCPM also provides a certain level of stability with a schedule update due to the newly identified resource relationships. Based on the RCPM algorithm, a prototype RCPM system has been developed using Visual C++, Visual Basic, and Ra (Primavera Project Planner API). The system is integrated with P3, so that it reads project information directly from a P3 project, performs necessary RCPM procedures, and updates the P3 project to contain identified resource relationships. To make the system more practical, functions to handle multiple project calendars and progressed schedules have been included as well. / Ph. D.
105

A Comprehensive Practice of Total Float Pre-Allocation and Management for the Application of A CPM-Based Construction Contract

Prateapusanond, Apirath 21 January 2004 (has links)
Many construction contracts require contractors to use the Critical Path Method (CPM) scheduling technique as a management tool. In such projects, many participating parties commonly attempt to appropriate float time shown in the CPM schedules in order to advance their own interests. Under current scheduling practices, float time is considered "free" and therefore does not belong to any one party in the construction process. As a result of this conception, when a project delay occurs, float ownership and its utilization can become a major source of dispute. This ambiguous interpretation of total float ownership can be clarified by improving contract language with regard to scheduling specifications in the area of total float management. The purpose of this research dissertation is to introduce a comprehensive practice of float pre-allocation and management terms, for the application of scheduling specifications in the CPM-based construction contract. The proposed concept for managing "total float" involves pre-allocating a set amount of total float on the same non-critical path of activities to the two contractual parties - owner and contractor. For the sake of equity, this research adopts an equal (50-50) allocation concept, which allocates to each party one-half of the total float. This new concept for pre-allocating and managing "total float" involves recommending contract clauses to direct its use and to explain the manner in which responsibility for any resulting delay will be assigned. Six examples of factual situations are provided to illustrate the assigning of responsibility for delays. The features of proposed concept are then compared to those of other theories presently being used. Such a comparison provides insight as to which features have not worked well in the past - and how those of the proposed concept can change this. A Delphi survey is used to validate the total float pre-allocation concept of equal allocation. The survey shows that the concept could significantly increase involved parties' awareness of total float consumption and thus help resolve any potential disputes regarding it. This dissertation considers suggestions obtained from the survey and recommends them for future study. The simple step of inserting new scheduling language into the construction contract documents assures that all participants will become more aware of the fact that when they consume floats, they introduce the potential of increasing project completion times. / Ph. D.
106

An evaluation of Training for Trainers (T4T) as an aid for developing sustained church planting movements (CPMs)

Smith, Stephen Robert 09 1900 (has links)
This paper attempts to evaluate Training for Trainers (T4T) as an aid for developing healthy and sustained church planting movements (CPMs). The thesis is that Training for Trainers (T4T) can enable and sustain (by the Spirit’s power) healthy church planting movements because a discipleship process is built into the methodology that develops believers in their personal and communal growth and equips them to repeat the process with other individuals they reach. The very format of the T4T process provides a context for developing disciples inwardly and training disciples to minister outwardly. The T4T process continues over the course of months and years to systematically move believers through the essential stages of sustained church planting movements: Bridges in conversations with the lost from non-spiritual topics to the gospel in order to find those God is preparing (knowing whom to talk to and how to start) • Reproducible evangelism methods that are effective in the local context and can be learned by any new believer • Reproducible discipleship that addresses both short-term and long-term spiritual growth in a manner appropriate to the local worldview and able to be passed on by a new believer • Reproducible church models appropriate to the local context and able to be led and passed on by new believers • Leadership development and multiplication patterns that develop leaders rapidly in the context of ministry and enable the number of leaders to keep pace with the number of new churches. T4T moves each new generation of disciples (trainers) and churches through this process because it casts vision for and gives loving accountability for disciples to truly become trainers of others. It does this primarily through a three-thirds training process. T4T is training for trainers who will train trainers who will train trainers. T4T attempts to initiate movements of God in which at least four generations of new disciples and churches emerge. This paper evaluates T4T is based on case studies, survey instruments and biblical principles and then offers recommendations for CPM practitioners. / Christian Spirituality, Church History and Missiology / D. Th. (Missiology)
107

Att äta kakan och ha den kvar : En studie om universitetsstudenters medvetenhet, attityd, och beteende gällande cookies

Jonasson, Fanny, Oskarsson, Amanda January 2019 (has links)
Cookies är idag ett utbrett fenomen som nyttjas vid digital insamling av information. Informationen som samlas in är ofta av personlig karaktär och används bland annat för att individanpassa användarupplevelser på webbsidor. Ovissheten kring digital insamling av personlig information skapar en oro som idag är mycket omdebatterad. Detta arbete utgörs av en kvantitativ studie med syfte att undersöka möjliga samband mellan universitetsstudenters medvetenhet, attityd och beteende gällande digital insamling av information. Undersökningen består av en onlinebaserad enkät. Det insamlade materialet har analyserats utifrån det teoretiska ramverket Communication Privacy Management (CPM) med hjälp av analysmetoden Partial Least Squares (PLS) samt IBM Statistical Package for Social Sciences (SPSS) för att finna relevanta samband. Resultat påvisade att majoriteten universitetsstudenter känner till fenomenet cookies, men färre känner till dess användningsområden. Det konstaterades även att medvetenhet kring cookies har en påverkan på både beteende och attityd. Det fastställdes även att oavsett om universitetsstudenter har en negativ attityd förändras inte dess beteende. / Cookies are a widespread phenomenon and the main technique for digital collection of information. The collected information is often of personal nature and is used, among other things, to personalize user experiences on web pages. The uncertainty regarding digital collection of personal information creates privacy concerns that is significantly debated today. This essay consists of a quantitative study with the aim to investigate possible relations between university students awareness, attitude and behaviour regarding digital collection of information. The survey consist of an online-based poll. The gathered material has been analyzed by the theoretical framework Communication Communication Management (CPM) with the analysis method Partial Least Squares (PLS) and the IBM Statistical Package for Social Sciences (SPSS) to find relevant relations. Results showed that the majority of university students are familiar with the phenomenon of cookies, but few are aware of its area of use. It was also found that awareness of cookies has an influence on both behaviour and attitude. It can be established that regardless of whether university students have a negative or positive attitude regarding cookies, it does not affect their behaviour.
108

Fonction, expression et localisation cellulaire du récepteur B1 des kinines chez le rat diabétique

Haddad, Youssef 12 1900 (has links)
No description available.
109

Receiver Design For A Class Of New Pulse Shapes For Cpm Signals

Ugurlu, Bilal 01 February 2012 (has links) (PDF)
Recently, a study on obtaining better Euclidean distance for CPM (Continuous Phase Modulation) signals that fit well-known GSM spectral envelope has been carried out, and significant performance improvements were obtained. Two new pulse shapes, which are represented using 8th degree polynomials, were optimized to give the best error performance under the constraint that the PSD stays below GSM spectral standards. However, the approach uses parameters that cause the number of states to increase considerably, and thus yielding high complexity for receiver implementation. In this thesis, a study on finding a feasible receiver design that can provide a performance with acceptable degradation but affordable complexity is carried out for those new pulse shapes. After a survey about complexity reduction techniques, a decision is made to go on with a receiver structure based on Laurent Decomposition (LD) of phase modulated signals. Unlike other complexity reduction techniques, usage of LD based receivers permits reduction in both the number of matched filters and trellis states. Throughout the study, different numbers of matched filters and trellis states were used in LD based receivers for the new pulse shapes, and good results are obtained. For the pulse shape with pulse length L = 3, about a gain of 0.93dB in power is achieved by only 2 matched filters and 14 trellis states. For the case where L = 7, approximately a gain of 2.25dB is achieved with only 8 matched filters and 56 states, whereas 896 matched filters and 448 states are needed in the optimum case without complexity reduction.
110

Tvorba softwarové podpory metody CCPM v prostředí MS Project / Development of software support for CCPM method in MS Project

Herout, Jan January 2009 (has links)
Project management, to which the thesis "Development of software support for CCPM method in MS Project" aims, is a very important part of everyday life for most present companies. The project management has gone through rapid development, through the second half of last century, during which many new techniques and methods, for planning and managing projects, were developed. One of these methods was critical chain project management method (CCPM), developed by E. M. Goldratt in the mid 80th of last century. At the end of the 20th century the market began to be flooded by software applications which supported project management, thanks to the boom of information and communication technologies. Because the CCPM method is still too young, there is only a very little amount of products aimed at this method. Author of the thesis took as its main objective the development of a software application that would serve to support the project management by CCPM method, and will work as an extension to an existing, widely used product, MS Project. To achieve this objective, few secondary objectives have to be met. The first is to characterize methods for project management with a focus on the critical chain project management method, including the description of the advantages and disadvantages of this method. These objectives will be achieved with the help of literature search, supplemented by knowledge gained by studying the issue at the college. Another secondary objective is to find, analyze and compare existing software used for project management support with CCPM method. For the primary analysis the author mainly uses information supplied by developers of these products, for the deeper analysis is used a model project that examines the behavior of the application in standard situations. For product comparison is made a group of criteria, which can also serve for potential readers as the basis for decision of the choice of suitable application for their needs. The main objective of the work, the development of the application, is based on the requirements set on the basis of information obtained from literature and on the results from testing of existing applications. This application is considered to be the greatest benefit of the thesis. In the end of the thesis the newly developed application is compared with existing products, by testing on a model project and by evaluating with a group of criteria established for evaluation of existing products.

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