• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 229
  • 165
  • 61
  • 49
  • 40
  • 8
  • 7
  • 7
  • 6
  • 4
  • 4
  • 3
  • 3
  • 2
  • 2
  • Tagged with
  • 678
  • 160
  • 121
  • 89
  • 86
  • 82
  • 75
  • 55
  • 43
  • 41
  • 39
  • 39
  • 37
  • 37
  • 35
  • 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.
361

Black mangrove (Avicennia sp.) colony expansion in the Gulf of Mexico with climate change : implications for wetland health and resistance to rising sea levels

Comeaux, Rebecca Suzanne 16 February 2011 (has links)
Populations of black mangroves (Avicennia sp.) are hypothesized to expand their latitudinal range with global climate change in the 21st century, induced by a reduction in the frequency and severity of coastal freezes, which are known to limit mangrove colony extent and individual tree size, as well as an overall warmer climate. The Gulf of Mexico is located at the northward limit of black mangrove habitat and is therefore a prime candidate for population expansion with global warming. This expansion may come at the expense of existing Gulf coastal saline wetlands that are dominantly Spartina spp. marsh grasses. The present study was conducted to focus, not on the extent to date of this replacement, but to examine the potential implications of a marsh to mangrove transition in Gulf wetlands, specifically 1) resistance to accelerating eustatic sea level rise (ESLR) rates, 2) wetland resistance to wave attack in large storms (increased cyclonic storm frequency/intensity is predicted with future climate warming), and 3) organic carbon sequestration and wetland soil geochemistry. Field sites of adjacent and intergrown Avicennia mangrove and Spartina marsh populations in similar geomorphological setting were selected in back-barrier areas near Port Aransas and Galveston, TX (two sites each) as part of a larger-scale planned study of the full latitudinal transition of the western Gulf funded by the National Institute for Climate Change Research (U.S. Department of Energy). The reconnaissance conducted for site surveys show that black mangrove populations in this part of Texas are clustered near inlet areas, suggesting seed transport vectors are a major control on colony establishment, and likely, on the potential rapidity of wetland habitat replacement. Resistance to ESLR was tested by 1) creating high-accuracy (±1 cm) elevation maps over ~5,000 m² areas of adjacent mangrove and marsh areas, and 2) measuring mineral and organic matter accumulation rates (Pb/Cs radiotracer geochronology, loss on ignition) from auger cores. Elevation surveys in Port Aransas indicate mangrove vegetated areas are 4 cm higher in elevation than surrounding marsh on an average regional scale, and 1 to 2 cm higher at the individual mangrove scale: at the Galveston sites, any trend is complicated by the area's pre-existing geomorphology and the relative youth of the mangrove colonies. ¹³⁷Cs accumulation rates and loss on ignition data indicate that mineral trapping is 4.1 times higher and sediment organics are 1.7 times lower in mangroves at Port Aransas; no such definable trends exist at the Galveston sites or in calculated ²¹⁰Pb sediment accumulation rates. This additional mineral particle trapping in mangroves does not differ in grain size character from marsh mineral accumulation. Elevation change may also be effected by root volume displacement: live root weight measurements in the rooted horizon (~0 to 20 cm depth) are consistently higher in mangrove cores from Port Aransas and the site at the west end of Galveston Island. Port Aransas porosities are lower in mangrove rooted horizons, with a corresponding increase in sediment strength (measured by shear vane in the cores), suggesting mangrove intervals may be more resistant to wave-induced erosion during storm events. Port Aransas mangroves exhibit higher pore water redox potentials and salinities over entire core depths and depressed pH over rooted intervals, suggesting a distinct diagenetic environment exists relative to marsh sites. Increased salinities and higher redox potentials may be a function of the rooting network, which introduces oxygen into the sediment and focuses evapo-transpiration and salt exclusion within this zone: this may prove advantageous when competing with marsh grasses by elevating salinities to levels that are toxic for Spartina. Trends observed in the more mature systems of Port Aransas are generally absent at the Galveston sites, suggesting the youth and physically shorter stature of these systems means they have not yet established a unique sediment signature. / text
362

Colonia menonita de La Pampa

Cuello, Pablo David January 2008 (has links)
Programa de investigación: Comunicación, Prácticas Socioculturales y Subjetividad <br> Información extraída de: <a href="http://perio.unlp.edu.ar/tesis/?q=node/23">http://perio.unlp.edu.ar/tesis/?q=node/23</a>
363

NOSEMA CERANAE IN WESTERN HONEY BEES (APIS MELLIFERA): BIOLOGY AND MANAGEMENT

Williams, Geoffrey Rhys 27 March 2013 (has links)
Western honey bees (Apis mellifera; hereafter honey bees) provide vital pollination services to global agriculture and biodiversity. However in recent years they have experienced severe population declines in many regions of the northern hemisphere. Although causes of these honey bee declines are not well understood, multiple pressures such as changes in land-use and climate, management issues, and introduced parasites are believed to be responsible. First described in honey bees in 2006 during a period of high colony mortalities, the microsporidian gut parasite Nosema ceranae became of great concern. In this dissertation I investigated the distribution, management, virulence, and inter-specific interactions of this introduced species. First, I described and clarified the multiple pressures believed to influence honey bee health, including N. ceranae, especially in relation to the mysterious phenomenon Colony Collapse Disorder. I then surveyed colonies in Maritime Canada for N. ceranae and the historic honey bee microsporidian Nosema apis. Although both species were present at a regional scale, intensive sampling in Nova Scotia revealed that N. ceranae was highly prevalent compared to the historic congener. Next, I investigated two potential management options for the parasite. Chemotherapy using the fungicide fumagillin reduced N. ceranae spore intensity but had no effect on colony survival, and indoor over-wintering did not reduce spore intensity but was associated with increased colony survivorship in spring. Using a comparative approach, I observed that N. ceranae infection significantly reduced honey bee longevity in the laboratory but did not influence overall colony health or strength in the field. Last, a laboratory study demonstrated reduced spore production during N. ceranae and N. apis co-infection, possibly due to inter-specific competition that has resulted in the displacement of the historic Nosema species by N. ceranae in many global regions. This dissertation provides crucial information on biology and management of N. ceranae that can be used towards the development of an integrated pest management strategy, and for future studies investigating factors that may influence the parasite’s distribution, virulence, and inter-specific interactions.
364

Dirbtinės bičių kolonijos algoritmai ir jų taikymai skirstymo uždaviniams spręsti / Artificial Bee Colony Algorithms and their Application to Assigment Problems

Matakas, Linas 29 July 2013 (has links)
Šiame darbe yra trumpai apžvelgiami dalelių spiečių sistemų algoritmai, skirstymo uždaviniai ir jų formuluotės, bei praktinės interpretacijos, plačiau apžvelgiami ir analizuojami dirbtinių bičių kolonijų algoritmai. Taip pat šiame darbe galima rasti dirbtinių bičių kolonijų algoritmo pritaikymą skirstymo uždaviniams spręsti, bei sukurtos programos skaičiavimo rezultatų analizę. / This paper consists of short descriptions of swarm systems algorithms, assigment problems and longer overview of artificial bee colony algorithms and it‘s analysis. Moreover, you can find an Artificial Bee Colony Algorithm's Application to one of an Assigment Problems and it's computational results analysis.
365

Dirbtinės bičių kolonijos algoritmai ir jų taikymai maršrutų optimizavimo uždaviniams spręsti / Artificial Bee Colony Algorithms and their Application to Route Optimisation Problems

Kavaliauskas, Donatas 29 July 2013 (has links)
Šiame darbe yra trumpai apžvelgiami dalelių spiečių sistemų algoritmai, maršrutų optimizavimo uždaviniai ir jų formuluotės, bei praktinės interpretacijos. Plačiau apžvelgiami dirbtinių bičių kolonijų algoritmai ir jų pritaikymas keliaujančio pirklio uždaviniams spręsti. Taip pat šiame darbe galima rasti dirbtinių bičių kolonijų algoritmo pritaikymą keliaujančio pirklio uždaviniams spręsti, bei sukurtos programos skaičiavimo rezultatų analizę. / This paper consists of short description of swarm systems algorithms, route optimisation problems overview and longer description of artificial bee colony algorithms adaptation for traveling salesman problem. Moreover, you can find an artificial bee colony algorithm's application to traveling salesman problem and analysis of computational results.
366

Epithelial and vascular progenitors in the developing lung: Newer insights and therapeutic implications

Stanislaus Alphonse, Anthuvan Rajesh Unknown Date
No description available.
367

The impact of the white settlers on the natural environment of Natal, 1845-1870.

Ellis, Beverley. January 1998 (has links)
As no other study of settler impact on the Natal environment exists for the early colonial period, this thesis is a pioneering work. It aims to document the changes white settlers made to the natural environment of Natal between 1845 and 1870. In order to do that, an understanding of the state of the environment by 1845 first had to be reached. This involved outlining briefly the nature of the environment and then assessing the impact made by the Iron Age farmers, the white hunter-traders, and the Boers of the Republic. The establishment of the Colony in 1845 meant that Natal was now in the hands of British administrators, determined to discover and utilize the resources of this outpost of the British Empire. The arrival and distribution of about 5 000 settlers in the early 1850s made the white population of Natal predominantly urban and British. Imbued with the idea of progress these settlers attempted to produce for their own subsistence and, where possible, sufficient surplus to sell for profit on the market. In so doing they not only perpetuated and intensified types of environmental exploitation already operating in Natal, but also initiated new ones. Over a period of twenty-five years, the comparatively small settler population was responsible for the irreversible transformation of the landform and mineral resources, flora and fauna of Natal. This thesis details the changes the settlers caused, on a regjon-by-region basis, but lack of evidence in some areas - despite extensive research - has resulted in several lacunae in the overall picture. However, as the conclusion shows, the general pattern of exploitation of the Natal settlers was not unique, but in fact mirrored that of settler societies in Australia and North America. / Thesis (M.A.)-University of Natal, Pietermaritzburg, 1998
368

P53 baltymo raiškos ir kitų veiksnių prognozinės vertės tyrimas, gydant krūties vėžį chemoterapija ir granuliocitų kolonijas stimuliuojančiais faktoriais / Chemotherapy and granulocyte-colony stimulating factors in treatment of breast cancer: prognostic value of p53 protein expression and other factors

Liutkauskienė, Sigita 22 November 2010 (has links)
Disertaciniame darbe analizuojama ankstyvo ir metastazavusio krūties vėžio prognozė priklausomai nuo skirtos chemoterapijos dozės ir molekulinių žymenų. Tyrimas susidėjo iš trijų etapų. I tyrimo etape buvo atlikta molekulinių žymenų (p53 baltymo, HER2, estrogeno ir progesterono receptorių) prognozinės vertės analizė retrospektyviojo ankstyvo krūties vėžio tyrimo metu, kartu įvertinta sumažintos chemoterapijos dozės įtaka ligos išeitims. II tyrimo etape ištirtas naujo rGKSF filgrastimo saugumas ir veiksmingumas gydant chemoterapija metastazavusį krūties vėžį. III tyrimo etape atlikta molekulinių žymenų prognozinės vertės analizė, eliminavus chemoterapijos dozės įtaką klinikinėms ligos išeitims, gydymą optimalia cheminio preparato doze užtikrinus prospekyviajame daugiacentriame naujo rGKSF saugumo ir veiksmingumo tyrime. Darbo uždaviniai 1. Nustatyti antraciklinų dozės įtaką sergančiųjų ankstyvu krūties vė¬žiu išgyvenamumui. 2. Ištirti p53 baltymo raiškos, kitų molekulinių žymenų ir gydymo ypatumų įtaką ankstyvo krūties vėžio prognozei. 3. Įvertinti febrilios neutropenijos profilaktikai skiriamo naujo rGKSF saugumą, gydant metastazavusį krūties vėžį. 4. Įvertinti febrilios neutropenijos profilaktikai skiriamo naujo rGKSF veiksmingumą, gydant metastazavusį krūties vėžį. 5. Nustatyti metastazavusiu krūties vėžiu sergančių pacienčių išgyvenamumo priklausomybę nuo atsako į skiriamą gydymą. 6. Įvertinti krūties vėžio prognozę įtakojančių molekulinių žymenų tarpusavio sąsajas. / This study investigated the clinical outcomes in early and metastatic breast cancer patients depending on chemotherapy and molecular markers. The study comprised of 3 parts: Part I - retrospective investigation of molecular markers (p53 protein, HER2 receptors, estrogene and progesterone receptors) and chemotherapy dose reduction in early stage breast cancer; Part II - prospective open-label multicenter phase IV clinical trial on safety and effectiveness of GCSF used in chemotherapy of metastatic breast cancer; Part III - investigation of prognostic value of p53 protein expression and other molecular markers in metastatic breast cancer when optimal chemotherapy dose was adjusted in prospective multicenter trial of new rGCSF on safety and effectiveness used in chemotherapy of metastatic breast cancer. Objectives: 1. To establish the influence of anthracycline dose on survival of early stage breast cancer patients. 2. To evaluate the influence of p53 protein expression and other molecular markers as well as treatment on prognosis of early stage breast cancer. 3. To establish the safety of new rGCSF prescribed for prevention of febrile neutropenia in chemotherapy of metastatic breast cancer. 4. To analyze the effectiveness of new rGCSF prescribed for prevention of febrile neutropenia in chemotherapy of metastatic breast cancer. 5. To establish the relationship between response to treatment and survival in metastatic breast cancer patients. 6. To evaluate the associations among... [to full text]
369

Site and services project case study, Ahmedabad, India

Mellin, Robert. January 1984 (has links)
No description available.
370

Granulocyte-macrophage colony stimulating factor (GM-CSF) : a paracrine regulator in the pre-implantation mouse uterus / Sarah A. Robertson.

Robertson, Sarah A. January 1993 (has links)
Bibliography: leaves 175-203. / xxix, 203 leaves, [14] leaves of plates : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Investigates whether cytokines influence the development of the embryo prior to implantation. / Thesis (Ph.D.)--University of Adelaide, Depts. of Obstetrics and Gynaecology and Microbiology and Immunology, 1993

Page generated in 0.1815 seconds