• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 237
  • 43
  • 41
  • 26
  • 24
  • 12
  • 10
  • 7
  • 6
  • 6
  • 4
  • 4
  • 4
  • 3
  • 3
  • Tagged with
  • 522
  • 249
  • 231
  • 105
  • 55
  • 51
  • 51
  • 48
  • 45
  • 42
  • 34
  • 33
  • 33
  • 32
  • 29
  • 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.
1

Effects of season and regulated photoperiod on the reproductive performance of sows

Chokoe, TC, Siebrits, FK 26 March 2009 (has links)
Abstract Reproductive performance of experimental commercial Dalland sows (n = 87) maintained under a constant photoperiod (10 h light and 14 h darkness) and control sows (n = 187) maintained under natural daylight length (10.4 h light in winter and 13.4 h light in summer) were compared. In early summer 4.1% of experimental sows returned to oestrus compared to 20.8% of the control sows. In late summer 9.1% of experimental sows returned to oestrus compared to 21.9% of the control sows. Reduced photoperiod improved the farrowing rate of experimental sows in the early summer breeding compared to the control group (95.4% and 81.3%, respectively). With winter breeding there was a small proportion of sows that returned to service in both groups (7.9% and 8.9%) while the farrowing rate was high in both groups (93.9% and 91.0% in the experimental and control groups, respectively). Litter sizes derived from early summer services were 11.4 and 11.6 for the experimental and control groups, respectively, while winter services led to litter sizes of 11.6 and 12.4 whereas in late summer services, regulated photoperiod had improved the litter size of the experimental group (12.3) compared to the control group (11.2).
2

Mutation in a light-regulated glucan synthase-like gene (gsl12) displays light hyper-responsive and callose deficient phenotypes in arabidopsis

Byun, Bohyun 15 May 2009 (has links)
Light is a very important factor affecting every aspect of plant development. Plant developmental responses to light are sensitive to the direction, intensity, color, and duration of light. Light is perceived by an extensive set of photoreceptors that includes the red/far-red light–absorbing phytochromes and blue/UV-A light–absorbing cryptochromes. The Arabidopsis mutant seedling hyper-responsive to light 6 (shl6) has exaggerated developmental responses to available light. In the low light, shl6 seedlings have a phenotype similar to wild-type plants grown in high light, with short hypocotyls, expanded cotyledons, and well-developed first true leaves. In addition, the roots of shl6 are short and highly branched. The SHL6 gene was mapped to a position on chromosome 5 between simple sequence length polymorphism (SSLP) markers nga249 and nga151. Two cosmid clones from this interval (introduced by Agrobacterium-mediated transformation) complemented the shl6 mutant phenotype. One candidate gene identified by complementation is a member of the glycosyltransferase family. The sequence of shl6 mutant differs from wild type Columbia allele of this gene (At5g13000) by a single nucleotide substitution in the first exon. This putative SHL6 gene encodes a member of a glycan synthase-like (GSL12) gene family that includes callose synthase. The β-1,3-D-glucan callose is found in the cell plate of dividing cells, in pollen mother cell walls, and pollen tubes. Callose synthase and related genes have not been previously implicated in developmental responses to light. We also observed that 90% of Col-0 anthers showed high callose deposition, but shl6 mutant did not display callose deposition in the anthers. The pollen viability in the shl6 was lower than Col-0. The epidermal cell elongation in shl6 hypocotyls was reduced when compared with Col-0. Therefore, we conclude that the mutation in light-regulated SHL6/GSL12 was involved in the synthesis of callose as well as light signaling.
3

Behaviour and ownership in the theory of competition and regulation

Hardt, Michael Hermann January 1996 (has links)
Ownership matters. It affects residual rights under incomplete contracts and, therefore, incentives. The first chapter of this thesis analyzes in how far ownership can be substituted by other economic factors. Contrary to an assumption found in the literature market foreclosure can be achieved without vertical integration in the following scenarios: repeated games, reputation games, and also in a finitely repeated game when there are switching costs. The main chapter is concerned with implications of ownership in regulated industries where a monopolistic supplier of an essential input is required by a regulator to charge cost based prices. Our analysis focuses on the impact of ownership on the monopolist's incentives to exploit informational asymmetries about production costs. We conduct a comparative study of vertical integration, vertical separation, and joint ownership. Effects on welfare, investments incentives, and entry are analyzed for each ownership structure. Joint ownership performs best. Accounting separation is shown to be generally ineffective as regulatory instrument. We use an alternative model which allows to take into account network duplication. Starting from a free market analysis of equilibrium pricing and entry decisions we explore the relation between ownership and the degree of regulation required in order to ensure efficient outcomes. Two part tariffs, network duplication, price discrimination and a long-term commitment to fixed input prices induce reductions of final prices. The final part of this thesis investigates results in the theory of competitive market equilibrium. Many of these results rely on restrictive assumptions on consumer behaviour. We analyze in how far traditional equilibrium theory is robust against a relaxation of underlying assumptions. We do not assume agents to be rational in the sense that their choices arise from maximisation. Randomly fluctuating demand is allowed for and consequences for predictions made by traditional competitive equilibrium theory are re-examined.
4

The Development of an E-Learning Course Incorporating Self-Regulated Learning Procedures into a PSI-Based Course

Pan, Xin 19 October 2012 (has links)
This developmental research adopted an adapted Personalized System of Instruction (PSI) structure to design an e-learning course module and a learning procedure, and embedded a self-regulated learning procedure into the PSI course. A set of self-regulated learning tools were developed and applied in this process. Through this PSI-based course, students learned a comparative culture study topic and learned to develop their self-regulated learning skills. This research also conducted Formative Evaluation. Suggestions from expert review and small group evaluation were used to design and revise this module and learning procedure. Evaluation outcomes from expert review and small group evaluation confirmed that this SRL embedded PSI framework was applicable for this e-learning environment. Implications for future use in both academic and practical areas were discussed. / Ph. D.
5

Transimpedance Amplifier (TIA) Design for 400 Gb/s Optical Fiber Communications

Ahmed, Maruf Newaz 24 May 2013 (has links)
Analogcircuit/IC design for high speed optical fiber communication is a fairly new research area in Dr. Ha's group. In the first project sponsored by ETRI (Electronics and Telecommunication Research Institute) we started to design the building blocks of receiver for next generation 400 Gb/s optical fiber communication. In this thesis research a transceiver architecture based on 4x100 Gb/s parallel communication is proposed. As part of the receiver, a transimpedance amplifier for 100 Gb/s optical communication is designed, analyzed and simulated. Simulation results demonstrate the excellent feasibility of proposed architecture. Bipolar technology based on III-V materials (e.g. - GaAs, InP based HBT, HEMT) has always dominated the high speed optical transceiver design because of their inherent properties of high mobility and low noise. But they are power hungry and bulky in size which made them less attractive for highly integrated circuit design. On the contrary, CMOS technology always drew attraction because of low cost, low power dissipation and high level of integration facility. But their notorious parasitic characteristic and inferior noise performance makes high speed transceiver design very challenging. The emergence of nano-scale CMOS offer highly scaled feature sized transistors with transition frequencies exceeding 200 GHz and can improve optical receiver performance significantly. Increasing bandwidth to meet the target data rate is the most challenging task of TIA design especially in CMOS technology. Several CMOS TIA architectures have been published recently [6]-[11] for 40 Gb/s data rate having bandwidth no more than 40 GHz. In contrast to existing works, the goal of this research is to step further and design a single channel stand-alone TIA compatible in serial 100 Gb/s data rate with enhanced bandwidth and optimized transimpedance gain, input referred noise and group delay variation. A 100 Gb/s transimpedance amplifier (TIA) for optical receiver front end is designed in this work. To achieve wide bandwidth and low group delay variation a differential TIA with active feedback network is proposed. Proposed design also combines regulated cascode front end, peaking inductors and capacitive degeneration to have wide band response. Simulation results show 70 GHz bandwidth, 42 dBΩ transimpedance gain and 2.8 ps of group delay variation for proposed architecture. Input referred noise current density is 26 pA/â while the total power dissipation from 1.2V supply is 24mW. Performance of the proposed TIA is compared with other existing TIAs, and the proposed TIA shows significant improvement in bandwidth and group delay variation compared to other existing TIA architectures. / Master of Science
6

A Self-Regulated Learning Inventory Based on a Six-Dimensional Model of SRL

Nuttall, Christopher 01 December 2016 (has links)
This report discusses a study undertaken to develop, pilot, and tentatively validate a self- regulated learning (SRL) inventory for L2 contexts. This inventory was specifically designed to measure learners' ability to self-regulate their learning. Although there have been a few SRL inventories developed to measure this ability, they do not conform to the six-dimensional SRL model proposed by educational psychologists and backed by extensive research. This warranted the development of a new SRL inventory. The primary focus of this study was that of taking initial steps to develop such an inventory. These steps involved writing and refining items conforming to a six-dimensional SRL model. After selecting 30 items from the initial item pool, the SRL inventory was piloted. Both qualitative and quantitative measures were then employed to provide an initial indication of the inventory's trustworthiness, reliability, and validity.
7

The Effect of the Use of Self-Regulated Learning Strategies on College Students' Performance and Satisfaction in Physical Education

Ao, Man-Chih, res.cand@acu.edu.au January 2006 (has links)
The purpose of this study was to investigate whether using self-regulated learning strategies could promote college students’ learning and satisfaction in Physical Education. A quasi-experimental design, experimental group (N =49) and control group (N=51), was used to examine the effectiveness of a teaching intervention in achieving the goals of learning and satisfaction. Students undertaking the self-regulated learning intervention were compared with a group participating in standard curriculum instructional conditions. Three questionnaires were administered to identify 1) students’ entry characteristics, 2) their perceptions of their learning experiences, and 3) satisfaction. Students completed a students’ characteristics questionnaire in week 2. During the module, students responded to a learning experience questionnaire. At the conclusion of the module, students completed a tennis skills test and responded to a satisfaction questionnaire. The conceptual framework for this study included the independent variables of teaching strategy, mediating variables (students’ characteristics), and dependent variables (satisfaction and performance). The experimental study was conducted within this framework by use of an ANCOVA design. The main results were: 1. The experimental group scored significantly higher on measures reflecting self regulated learning processes in their learning experience than the control group (p=0.000).2. There was no difference between the groups on scores for global satisfaction (p=0.059).3. There was no difference between the groups on satisfaction through valuing (p=0.401). 4. The experimental group demonstrated significantly higher students' satisfaction through enjoyment than the control group (p=0.013).5. The experimental group had significantly higher performance in the tennis skills test than the control group (p=0.000). Several effects of self-regulated learning were indicated in this study. Analysis of the monitoring sheets provided evidence that students gained more interest and confidence in their involvement in the tennis class by the use of self-regulated learning strategies. However, it was expected that the self-regulated learning group would experience the greater satisfaction. As this did not occur, more research is needed to further examine the relationship of learning experiences to satisfaction and particularly the dimension of valuing. The importance of utilizing a conceptual framework that accounted for differences in student entry characteristics in a teaching intervention of this nature was demonstrated by the ANCOVA analysis. The individual factors of managing environmental change, problem solving, ability attributions, and task orientation were all shown to have some significant effects on student outcomes over and above those attributed to the learning experience. Finally, some interesting findings concerning the composition of the scales used in the study were reported. They were interpreted as providing evidence for the importance of verifying the cultural appropriateness of even well-known theoretical concepts that may have been developed in different contexts to those in which they are being used. The study concludes with some specific recommendations for future research.
8

Statistical Analysis of parameters of Yeast (Saccharomyces cerevisiae) cell cycle regulated genes

Wu, Chung-chiang 29 July 2004 (has links)
In this thesis, the main objective is to perform statistical analysis of parameters yeast cell cycle regulated genes. We have known that there are 800 cell cycle regulated genes from Spellman et al. [9] (Spellman¡¦s 800) and 687 cell cycle regulated genes from MIPS database (MIPS¡¦s 687). We analyze yeast cell cycle regulated genes with statistical methods and models. The four main index statistics considered are as follow: 1. numbers of triscription factors bind to promoters, 2. coherence of genes with 104 known regulated genes (KRG) in alpha-factor experiment, 3. coherence of genes with 104 KRG in cdc15 experiment, 4. coherence of genes with 104 KRG in cdc28 experiment. Although, binding numbers can be fitted to geometric distribution in two subgroups of genes, we found that it is infeasible to classify the cell cycle regulated genes by only using HMM, and the coherence method also improve Spellman classification results if the standard is MIPS database or the 104 KRG. Finally, the cell cycle classification criterion in MIPS¡¦s 687 genes are found to include the information given by Spellman¡¦s 800.
9

Medical Students’ Experience Using an e-Portfolio for Self-Regulated Learning in the Context of the Intrinsic CanMEDS Roles

MacKenzie, Jennifer 29 April 2014 (has links)
Self-regulated learning (SRL) is associated with academic and clinical achievement. Using Zimmerman’s (2002) framework, SRL includes a cycle of forethought, performance, and reflection. To support SRL, a web-based portfolio (e-Portfolio), in the context of the intrinsic CanMEDS Roles, was introduced for undergraduate medical students at a Canadian Medical School. This exploratory, qualitative study was designed to capture students’ descriptions of their behaviours using the e-Portfolio, to examine the extent to which these were consistent with SRL processes, and to analyze the gaps between intended and actual use. Data were collected using both semi-structured interviews and a 20-item, 5-point Likert-type instrument to prompt discussion. Second-year medical student volunteers were recruited for data collection until saturation of information was reached (n=14). Thematic and content analysis were used; data were interpreted using constructivist grounded theory (Creswell, 2007). Use of one interviewer, a standardized protocol, and member checking assured consistency and trustworthiness of the data. Students explicitly described the value of the e-Portfolio as an organizational tool, and as a form of assessment. Participants identified some elements of forethought and reflection but seldom described plans to achieve and measure outcomes. During the process of uploading materials to their e-Portfolio many of the students were able to make connections between the intrinsic CanMEDS Roles they are to assume as practicing physicians and the behaviours that operationalize these roles. Students viewed the e-Portfolio as a working folder compared to the faculty goal of a cumulative portfolio. Students endorsed self-selection of artifacts and faculty mentorship to improve relevance and future motivation for learning. Limitations included privacy concerns. Participants described a goal-oriented, in contrast to a process- or learning-oriented, approach to keeping their portfolios. The gap between students’ descriptions of portfolio use and SRL were most significant for the performance phase. The dual use of a portfolio for learning and assessment resulted in some compromises to the students’ use of the portfolio for learning. Strategies to improve SRL could include specific instruction on the nature and value of SRL, faculty mentorship during the learning process, and assessment of students’ learning processes. / Thesis (Master, Education) -- Queen's University, 2014-04-29 12:53:15.642
10

An Exploration of elementary students' task understanding: how do young students understand the school activities they are assigned?

Helm, Stephanie Catherine 19 January 2012 (has links)
This study employed a cross case analysis research design to explore young elementary students’ task understanding and its relationship to learning. Participants included 13 grade two students. Research was incorporated into the regular activities of a second grade class. Students learned about animal lifecycles and completed an associated activity (task) about the frog lifecycle during five hour-long sessions. The Task Understanding Questionnaire (TUQ), targeting students’ perceptions of explicit (e.g., task requirements) and implicit (e.g., course concepts, task purpose) task features, was administered at the end of each session. Findings indicate young students’ task understanding accuracy varied. Students demonstrated strong, improved, and weak task perceptions. Task understanding was also associated with learning outcomes. For students with limited prior knowledge, accurate task understanding was related to successful learning. / Graduate

Page generated in 0.062 seconds