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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.
131

Flux d'azote dans une culture pérenne à vocation énergétique, Miscanthus x giganteus: étude expérimentale et éléments de modélisation

Loïc, Strullu 06 January 2011 (has links) (PDF)
L'utilisation de plantes dédiées pour la production d'énergie est souvent présentée comme l'une des solutions pour limiter le réchauffement climatique et contribuer au remplacement des énergies fossiles. La production de biocarburants sera durable si elle contribue à réduire les impacts négatifs de l'agriculture au niveau global (émissions de GES), mais aussi local (lessivage des nitrates, consommation en eau). Les cultures énergétiques doivent satisfaire ces exigences tout en alliant un rendement élevé à l'hectare, afin de limiter la concurrence entre productions alimentaires et non alimentaires. Nous avons orienté la thèse vers la quantification du rôle des organes de réserve de Miscanthus x giganteus dans la nutrition azotée de la plante et l'analyse du cycle interne de l'azote dans la culture, en vue d'une modélisation fonctionnelle de ces processus à long terme. L'approche expérimentale s'appuie sur un essai de longue durée de 3 ans, croisant 2 doses d'azote et 2 dates de coupe. Dans une première partie, nous montrons que les traitements ont différencié la production de biomasse aérienne et la teneur en azote des rhizomes. Les réserves souterraines jouent sur l'accumulation d'azote et de carbone dans les parties aériennes au cours de la croissance le printemps suivant. Il existe des relations linéaires étroites entre les flux d'azote et l'état des organes source d'azote lors des phases de remobilisation de l'azote au printemps et à l'automne. Dans une deuxième partie, nous montrons que ce sont principalement les réserves en azote des parties souterraines avant le redémarrage de la culture qui expliquent les différences de production de biomasse en affectant l'efficience de bioconversion des rayonnements (RUE). Dans une troisième partie, nous mettons en évidence la faible proportion de recouvrement dans la plante de l'azote apporté par la fertilisation, grâce à un traçage au 15N de l'azote apporté. Nous montrons également que le rhizome absorbe en même temps qu'il remobilise. M. giganteus est capable de maintenir un cycle de l'azote conservatif : la quantité d'azote remobilisée à l'automne est du même ordre de grandeur que l'azote remobilisé au printemps. Enfin, nous concluons sur les acquis et questions sur le rôle de la mise en réserve de l'azote dans la nutrition azotée de M. giganteus. Ce rôle est primordial, via les processus de remobilisation et de mise en réserve de l'azote. Il a un impact direct sur la production de biomasse par la culture. Prendre en compte les réserves azotées des organes souterrains est indispensable pour aboutir à une modélisation opérationnelle qui permette de simuler la production de biomasse par la culture et les bilans d'azote sur le long terme.
132

Climate variability, timing of nesting and breeding success of tree swallows (<i>Tachycineta bicolor</i>)

Fast, Marie 29 October 2007
Recent changes in climate have increased public attention and scientific evaluation of climate impacts on wild animals and plants. Variation in local weather and regional climate may affect breeding success in birds. Migratory species may be sensitive to these changes as breeding and wintering areas may experience different climate variations; some insectivorous species may be unable to alter timing of migration or laying dates and experience a mismatch between timing of nesting and peak insect availability for their nestlings. Therefore, I investigated the influence of local weather variables and regional climate on breeding performance of an insectivorous migrant songbird, the Tree Swallow (<i>Tachycineta bicolor</i>), and tried to examine effects of a mismatch between the timing of breeding and food availability.<p>I used a 14 year data set from St. Denis, Saskatchewan, Canada, 1991-2004, to evaluate correlations among local weather, wetland conditions, aerial insects and regional climate indices and their relationships with variation in clutch initiation date, clutch size, and fledging success. Swallows returned to the study site in late April each year. Annual variation in median clutch initiation date was best explained by mean minimum temperatures during 1-15 May. Larger clutches were laid in years with higher pond water levels (possibly an indication of increased insect availability) and when the Southern Oscillation Index (SOI) was positive (representing La Niña conditions). Fledging success was not influenced greatly by any explanatory variable; however, fledging success tended to increase in years with higher average temperatures. Individual variation in clutch initiation date was examined using path analysis. I found high correlations between initiation date and both local environmental variables and regional climate indices; earlier nesting was associated with warmer temperatures (increased local temperatures, more positive North Atlantic Oscillation Index (NAOI) values and more negative SOI values) and decreased moisture (more positive NAOI values). Two reduced data sets, including female age or insect abundance, were also examined. Clutches were initiated earlier by older females and during springs with higher abundance of aerial insects.<p>I applied two heating treatments to nest boxes used by pre-laying swallows and compared reproductive measures (timing of nesting, laying sequence, clutch size, egg weight and fledging success) of birds using heated boxes to those of females attending unheated control boxes. However, I was unable to directly examine the predictions of the mismatch hypothesis because nest box heating failed to advance laying dates. Furthermore, no increases in clutch size, egg weight and fledging success were detected between treatment and control nests. Although box heating increased nest temperatures an average of 6.1C (+ 0.8 SE) over controls, length of time females spent in heated boxes may have been too short to alleviate energetic constraints on egg production, or energy savings associated with box use were insufficient to supersede the influence of ambient environmental conditions that control food availability and energy expenditure of foraging swallows. My results demonstrated that local and regional climate variation strongly affected timing of nesting in swallows, likely via their effects on food supply.
133

Climate variability, timing of nesting and breeding success of tree swallows (<i>Tachycineta bicolor</i>)

Fast, Marie 29 October 2007 (has links)
Recent changes in climate have increased public attention and scientific evaluation of climate impacts on wild animals and plants. Variation in local weather and regional climate may affect breeding success in birds. Migratory species may be sensitive to these changes as breeding and wintering areas may experience different climate variations; some insectivorous species may be unable to alter timing of migration or laying dates and experience a mismatch between timing of nesting and peak insect availability for their nestlings. Therefore, I investigated the influence of local weather variables and regional climate on breeding performance of an insectivorous migrant songbird, the Tree Swallow (<i>Tachycineta bicolor</i>), and tried to examine effects of a mismatch between the timing of breeding and food availability.<p>I used a 14 year data set from St. Denis, Saskatchewan, Canada, 1991-2004, to evaluate correlations among local weather, wetland conditions, aerial insects and regional climate indices and their relationships with variation in clutch initiation date, clutch size, and fledging success. Swallows returned to the study site in late April each year. Annual variation in median clutch initiation date was best explained by mean minimum temperatures during 1-15 May. Larger clutches were laid in years with higher pond water levels (possibly an indication of increased insect availability) and when the Southern Oscillation Index (SOI) was positive (representing La Niña conditions). Fledging success was not influenced greatly by any explanatory variable; however, fledging success tended to increase in years with higher average temperatures. Individual variation in clutch initiation date was examined using path analysis. I found high correlations between initiation date and both local environmental variables and regional climate indices; earlier nesting was associated with warmer temperatures (increased local temperatures, more positive North Atlantic Oscillation Index (NAOI) values and more negative SOI values) and decreased moisture (more positive NAOI values). Two reduced data sets, including female age or insect abundance, were also examined. Clutches were initiated earlier by older females and during springs with higher abundance of aerial insects.<p>I applied two heating treatments to nest boxes used by pre-laying swallows and compared reproductive measures (timing of nesting, laying sequence, clutch size, egg weight and fledging success) of birds using heated boxes to those of females attending unheated control boxes. However, I was unable to directly examine the predictions of the mismatch hypothesis because nest box heating failed to advance laying dates. Furthermore, no increases in clutch size, egg weight and fledging success were detected between treatment and control nests. Although box heating increased nest temperatures an average of 6.1C (+ 0.8 SE) over controls, length of time females spent in heated boxes may have been too short to alleviate energetic constraints on egg production, or energy savings associated with box use were insufficient to supersede the influence of ambient environmental conditions that control food availability and energy expenditure of foraging swallows. My results demonstrated that local and regional climate variation strongly affected timing of nesting in swallows, likely via their effects on food supply.
134

佐賀県富士町, 雷山南麓の斜面堆積物に埋没したカヤのAMS^<14>C年代

長岡, 信治, Nagaoka, Shinji, 水田, 利穂, Mizuta, Tosjiho, 奥野, 充, Okuno, Mitsuru, 中村, 俊夫, Nakamura, Toshio, 光谷, 拓実, Mitsutani, Takumi 03 1900 (has links)
タンデトロン加速器質量分析計業績報告 Summaries of Researches Using AMS 1997 (平成9)年度
135

A few good men II : distinguishing between men with high and low endorsement of rape-supportive attitudes /

Sherrod, Nancy B. January 2002 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 2002. / Typescript. Vita. Includes bibliographical references (leaves 143-166). Also available on the Internet.
136

A few good men II distinguishing between men with high and low endorsement of rape-supportive attitudes /

Sherrod, Nancy B. January 2002 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 2002. / Typescript. Vita. Includes bibliographical references (leaves 143-166). Also available on the Internet.
137

DATE as a human capital strategy

Volonnino, Michael Robert 25 September 2013 (has links)
Performance incentives in education has frequently been presented in purely rational choice economic terms, looking to see if the input of an incentive produced the desired output of student achievement. Such research has continually failed to produce significant effects. This dissertation attempts to recast incentives in terms of human capital theory and human behavioral economics, looking at the impact of social capital and support structures on teacher response to incentives. This study examines a major performance pay program in Texas using a concurrent-nested, mixed methods design. It finds that an external motivator like incentives is only effective in the presence of factors of internal motivation and that social capital positively affects the impact of a performance incentive. / text
138

Saamwoon voor die huwelik : 'n teologies-etiese beoordeling / Johannes Georg Noëth

Noëth, Johannes Georg January 2005 (has links)
The problem that is studied is formulated in chapter 1. It boils down to the fact that nowadays, also in churches with 'mainly white congregations, there are different viewpoints on living together. It varies from a direct rejection to a de facto acceptance. In view of this research is done for the purpose of assessing cohabitation according to Scriptures. In chapter 2 the essence and purpose of the Christian marriage are portrayed. It becomes clear that it is God's will that sexual intercourse may only take place inside the marriage. In chapter 3 the main reasons for cohabitation are examined. It is found that if all the causes are considered in their close relationship with each other, a favourable infrastructure for living together is created and people are strongly influenced to live together. The practice of cohabitation is evaluated in chapter 4 by using 8 of the 9 social ethical norms formulated by Heyns in the light of Scriptures and applied by Steensma as normative viewpoints. It is found that cohabiting is at variance with all eight social ethical norms. It is also found that living together doesn't always result in marriage, and if it results in marriage, there is no guarantee that the marriage will succeed and will not end up in at court of divorce. In chapter 5 a summary is given of the problem identification and the results of the previous 4 chapters. Then a conclusion is made about cohabitation in the light of Scriptures, namely that it is in conflict with the will of God. In the third section guidelines are given for the purpose of pastoral guidance towards people who cohabit or plan to do so. The role of the government and topics for further studies about cohabitation are also given. / Thesis (Th.M. (Ethics))--North-West University, Potchefstroom Campus, 2005.
139

Agency Problems in Target-Date Funds

Sandhya, Vallapuzha 12 January 2012 (has links)
Target-Date Funds (TDFs) facilitate retirement planning by varying asset allocation over time with the goal of reducing portfolio risk. We explore potential agency problems in TDFs by examining their return performance and flow-performance relation. We find that TDFs under-perform balanced funds (BFs) which are also approved as a default option along with TDFs in 401(k) plans with automatic enrollment. We show that the under-performance is driven by TDFs that have a fund-of-fund structure and constituent funds with high expense ratios or poor performance within the fund family. Additionally, we discover an absence of flow-performance relation in TDFs while BFs exhibit the convex flow-performance relation shown for mutual funds. Our evidence suggests the presence of agency problems in TDFs arising from investor inertia, weak incentives for fund managers to outperform peers, and opportunities for fund families to gain private benefits.
140

Atsakomybė pateikus neteisingus duomenis apie pajamas, pelną ar turtą mokesčių administratoriui / Liability for submission of false data of income, profit or assets to tax administrator

Venclovaitė, Viktorija 22 January 2009 (has links)
Šiame magistro baigiamajame darbe autorė nagrinėja atsakomybę už neteisingų duomenų apie pajamas, pelną ir turtą pateikimą mokesčių administratoriui. Teisinė atsakomybė nagrinėjama sistemingai analizuojant Lietuvos Respublikos įstatymus, poįstatyminius teisės aktus, bei LRKT, LVAT ir LAT jurisprudenciją. Autorė nagrinėja administracinę, mokestinę ir baudžiamąją atsakomybę už neteisingų duomenų pateikimą mokesčių administratoriui. Analizuojant nagrinėjamos veikos sudėtį, iškeliamos teisinės atsakomybės rūšių atribojimo problemos. Daroma vienareikšmė išvada, kad neteisingų duomenų pateikimas mokesčių administratoriui yra valingas mokesčio mokėtojo veikimas siekiant išvengti arba nuslėpti mokesčius. Teisinės atsakomybės rūšies taikymas glaudžiai siejasi su mokesčių mokėtojo pareiga bendradarbiauti su mokesčių administratoriumi, tai atskleista nagrinėjat administracinę ir mokestinę atsakomybę už neteisingų duomenų pateikimą mokesčių administratoriui. Baudžiamoji atsakomybė mokesčių mokėtojui kyla tik tada, jeigu mokesčių administratoriui buvo pateikiami žinomai neteisingi duomenys apie savo pelną, turtą ar pajamas, taip siekiant išvengti mokesčių. Baigiamajame darbe taip pat atsakoma į klausimus, kaip mokesčių administratorius vertina mokesčio mokėtojo pateiktus duomenis, kaip nustatoma ar mokesčio mokėtojo duomenys yra neteisingi bei kaip tokiu atveju apskaičiuojami mokesčiai. Teisinė analizė paremta teisės normų taikymo praktika LRKT, LVAT ir LAT, taip pateikiant pagrindines... [toliau žr. visą tekstą] / The author of the thesis deals with liability for submission of false data to tax administrator. The thesis is based on system analysis of laws and bye-laws of the Republic of Lithuania as well as case-law of the Constitutional Court of the Republic of Lithuania, the Supreme Administrative Court of Lithuania and the Supreme Court of Lithuania. The author examines administrative, fiscal and criminal liability for submission of false data to tax administrator. The criteria used by tax administrator to determine whether the data submitted by a taxpayer is true are analyzed in the thesis. Also the methods of assessing tax base, when it is found that the data of a taxpayer is false, are comprehensively described. The conclusion is being drawn that submission of false data to tax administrator is a voluntary act of a taxpayer having an intention to avoid or conceal taxes. Application of type of legal liability is closely related to the duty of a taxpayer to cooperate with tax administrator; this is demonstrated by analyzing administrative and fiscal liability for submission of false data to tax administrator. Criminal liability is incurred only if a taxpayer has submitted knowingly false data regarding taxpayer’s profit, assets or income to tax administrator having an intention to avoid taxes. Legal analysis is based on application practice of legal norms by the Constitutional Court of the Republic of Lithuania, the Supreme Administrative Court of Lithuania and the Supreme Court of... [to full text]

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