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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.
201

Problems of Transportation Planning During Winter Storms in Portland, Oregon, and Seattle, Washington: A Comparative Study

January 2015 (has links)
abstract: Winter storms decrease the safety of roadways as it brings ice and snow to the roads and increases accidents, delays, and travel time. Not only are personal vehicles affected, but public transportation, commercial transportation, and emergency vehicles are affected as well. Portland, Oregon, and Seattle, Washington, both suffer from mild, but sometimes extreme, storms that affect the entire city. Taking a closer look at the number of crashes reported by the City of Portland and the City of Seattle, it is seen that there is an increase in percent of crashes with reported road conditions of snow and ice. Both cities appear to have nearly the same reported crash percentages. Recommendations in combating the issue of increased accidents and the disruption of the city itself include looking into communication between the climate research institution and city planners that could help with planning for better mitigation during storms, a street or gas tax, although an impact study is important to keep in mind to make sure no part of the population is at risk; and engineering revolutions such as Solar Roadways that could benefit all cities. / Dissertation/Thesis / Masters Thesis Urban and Environmental Planning 2015
202

Disenteria de inverno: detecção de coronavírus bovino (BCoV) por reação de PCR dirigida ao gene Rp Rd e isolamento em cultivo celular de HRT-18G / Winter dysentery: detection of bovine coronavirus (BCoV) by RT-PCR for the Rp Rd gene and isolation in monolayers of HRT-18G cells

Sabrina Sonza 13 March 2007 (has links)
Coronavirus bovino (BCoV), um membro da família i>Coronaviridae, causa severa diarréia em bezerros neonatos e tem sido associado a diarréias de inverno em vacas leiteiras em vários paises, incluindo o Brasil. A morbidade da disenteria de inverno e alta chegando ate 100% , sendo um fator importante para economia já que causa queda da produção leiteira, levando a grandes perdas as criações de vacas leiteiras. O objetivo deste trabalho foi pesquisar a ocorrência de BCoV em vacas, diagnosticando amostras positivas por RT-PCR gene Rp Rd e isolando estas amostras positivas em células da linhagem HRT-18G. As amostras de fecais foram obtidas de 43 vacas leiteiras com disenteria de 8 propriedades dos Estados de São Paulo e Minas Gerais, Brasil. Das dez (10/43=23%) amostras positivas para esta técnica, 7 foram inoculadas em células da linhagem HRT-18G, sendo que o isolamento foi comprovado pela mesma técnica após seis passagens seriadas em 4 inoculações. Com isso, mostra-se que o BCoV também esta envolvido em disenterias de inverno em vacas leiteiras no Brasil. E através de isolamentos deste vírus, podemos contribuir para estudos continuados ajudar no esclarecimento de sua epidemiologia e possibilitar com um banco de vírus a prevenção de ordem também especifica da enfermidade. / Bovine coronavirus (BCoV), a member of Coronaviridae family, causes severe diarrhea in newborn calves and has been associated with outbreaks of winter dysentery (WD) in adult cattle in several countries, including Brazil. The morbidity rate of WD is very high (50-100%) and the disease causes severe economic losses once it decreases milk production. The aim of the present study was to survey for the occurrence of BCoV in cows using a RT-PCR targeted to the replicase gene and to isolate positive samples in HRT-18G cells. The fecal samples were obtained from 43 adult dairy cows with dysentery from São Paulo and Minas Gerais States, Brazil. Ten (23%) of the 43 fecal samples were positive for BCoV and 7 of these were inoculated in HRT-18G cells, when the isolation of 4 samples was proved by RT-PCR after sex passages. These findings indicate that BCoV is also involved in outbreaks of dysentery in adult cattle in Brazil. This shows the importance of more comprehensive studies on coronavirus in dairy cattle in the surveyed area and, with the isolation of the virus strains studied herein, one may contribute to other studies to enlighten the epidemiology and prevention of the disease.
203

Fotoperíodo artificial no verão pode evitar anestro estacional na égua? / Could artificial photoperiod in summer avoid seasonal anestrus in the mare?

David, Fabíola Freire Albrecht de January 2011 (has links)
A égua é classificada como poliéstrica estacional, o que implica suspensão da atividade reprodutiva cíclica usualmente a partir da metade do outono, na maioria destes animais. Esta resposta é devida à diminuição gradual no fotoperíodo natural, considerado como fator primário na sazonalidade reprodutiva. A ausência de ciclos ovulatórios durante os meses de inverno e a inconsistência da fase de ressurgência atingem não só os criadores de raças que procuram o nascimento de potros mais cedo na temporada reprodutiva oficial, mas principalmente aqueles que empregam a técnica da transferência de embriões. A obtenção de ovulações ao longo do ano possibilitaria a utilização reprodutiva ótima de éguas doadoras e receptoras. A fim de verificar a ciclicidade reprodutiva durante outono e inverno, dezessete éguas em uma propriedade do sul do Brasil foram distribuídas ao acaso em dois grupos. De quinze de Janeiro a doze de Setembro de 2009, os animais do grupo Tratamento foram submetidos a fotoperíodo diário fixo de 15 horas. Duas vezes por semana, o trato reprodutivo de todos os animais foi avaliado por ultrassonografia transretal, para verificação da presença de folículos dominantes e corpo lúteo. Dosagem de progesterona foi utilizada para confirmação de anestro. Oitenta e cinco por cento dos animais submetidos ao tratamento mantiveram ciclicidade reprodutiva, enquanto oitenta por cento dos animais controle entraram em anestro de inverno. Houve aumento na duração dos ciclos, devido a fatores endógenos, nutricionais e ambientais. Os resultados demonstram que o tratamento foi efetivo para obtenção de ciclos ovulatórios durante os meses de inverno. / The mare is classified as a seasonal poliestric, which means the suspension of reproductive activity usually from the first half of autumn, most of the mares. This is a response to the gradual decline in the natural photoperiod, considered as a primary factor of reproductive seasonality. The absence of ovulatory cycles during winter months and the inconsistency of the resurging phase strike both breeders who aim foals’ birth early in the official breeding season and those who employ the embryo transfer technique. Achieving ovulation throughout the year would enable the optimal reproductive use of donors and recipient mares. In order to check autumn and winter cyclicity, seventeen mares on a farm in southern Brazil were randomly assigned into two groups. From January 15th to September 12th 2009, animals in Treatment group were subjected to a fixed 15 hours daily photoperiod. Twice a week, the reproductive tract of all animals was examined by transrectal ultrasonography, searching for dominant follicles and presence of corpora lutea. Progesterone levels were used to confirm winter anestrus. 85% mares undergoing treatment maintained reproductive activity, while 80% of Control mares showed winter anestrus. There were changes in lenght of cycles, due to endogenous, nutritional and environmental factors. Results demonstrate that the treatment was effective to attain ovulatory cycles during winter months.
204

Patterns of variation in energy management in wintering tits (<em>Paridae</em>)

Broggi, J. (Juli) 22 August 2006 (has links)
Abstract Winter energy management in small passerines living year-round in boreal or alpine areas presumably results in strong selective pressure since they need to find food, at a time when natural resources diminish and become less available, and energy requirements increase dramatically. In this thesis energy management during the non-breeding season was studied in three species of tits (Parus spp.), from three different populations: Coll de Pal (Spanish Pyrenees), Lund (Southern Sweden) and Oulu (Northern Finland). Energy management strategies vary significantly between species and among populations and individuals of the same species. Such differences may depend on several environmental factors, food predictability and individual characteristics. Birds from the studied populations appear to react to energetic challenges on a short-term basis and in a highly flexible way. The coal tit (Parus ater) in Coll de Pal and the willow tit (Parus montanus) in Oulu, both hoarding species, relied mostly on short-term management of energy for winter survival. Social and residence status appeared to be the most important factors in determining the level of energy reserves, underlining the importance of food predictability for energy management in wintering tits. Further studies were carried out on two distinct populations of great tit (Parus major) exposed to different winter hardiness. Birds from both populations increased their resting metabolic rate (MR) with experimentally decreasing ambient temperatures. Birds from Oulu maintained higher expenditures than birds from Lund in all cases, but also experienced higher energetic cost of thermoregulation at the lowest temperatures. The differences probably did not arise from a differential insulation capacity between populations, despite the differences in plumage structure found, but from a differential metabolic acclimatization. Birds from Lund probably became hypothermic at the lowest temperatures, which may have exceeded the levels they were acclimatized for. The observed differences in basal MR in laboratory conditions were consistent in wild birds throughout the non-breeding season. Birds from both populations experienced similar patterns of variation in basal MR, with expenditures increasing with mass but decreasing with day length, size and age. Great tits modulate their energy expenditure in a flexible way as a means for surviving the non-breeding season. Further, despite such flexibility, populations appear to be locally adapted for such metabolic acclimatization. These results may have important implications on their life-history and distribution. Winter acclimatization appears to be a complex set of entangled strategies that are based on a metabolic adjustment to cope with changing energy requirements. Other mechanisms that apparently play a secondary role, for example the long term management of reserves through fattening or hoarding, or conserving heat through hypothermia and by developing a better insulative plumage, are certainly important emergency strategies that in natural conditions may explain how some populations can endure winter conditions.
205

Avian nectarivory and pollination in Aloe marlothii Berger : interactions between bird communities and a winter-flowering succulent

Symes, Craig Thomas 18 November 2008 (has links)
Aloe marlothii is a winter-flowering succulent that is widespread in the savanna biome of northern and north-eastern South Africa. Plants grow up to 8 m in height and are commonly found on rocky north-facing slopes. Nectar production occurs through a 24 h period with flowers producing copious amounts (c. 250 µl) of dilute nectar (c. 12%). This abundant nectar supply, that is available for a 5-10 week period during June-August, is utilised by numerous opportunistic avian nectarivores. At a study site in Suikerbosrand Nature Reserve, 60 km south-east of Johannesburg, at least 59% (38 species) of birds recorded during census transects fed on nectar; throughout the range of A. marlothii at least 85 species feed on nectar. This diversity surely far exceeds the number of species ever recorded feeding on nectar of a single plant. During the flowering period an influx of birds at the aloe forest occurred, with an overall increase in abundance and diversity. Pollinator exclusion experiments supported the hypothesis that A. marlothii is pollinated by generalist birds; specialist nectarivores are possibly excluded as inefficient pollinators by the nectar of low concentration and high volume. Fruit set was higher in plants that had avian visitors and very low when pollinators were absent. Stable carbon isotope analysis of whole blood was used to quantify the importance of nectar sugars for opportunistic nectarivores. During flowering there was an enrichment in the δ13C isotopic signature of whole blood of nectar-feeding birds towards that of nectar (δ13C = -12.6‰). This shift was most prominent in frugivores, insectivores and omnivores that typically fed on a diet depleted in 13C when nectar was not available. The C4 grass seed diet of granivores was similar to the isotopic signature ofA. marlothii nectar, so we were unable to determine to what degree granivores benefitted from nectar. Stable nitrogen isotopes in whole blood may suggest that many nectar-feeding birds shift their trophic position during flowering. However, we interpret these results with caution because of insufficient knowledge on diet-tissue fractionation factors of wild birds and/or temporal changes in vegetation isotopic values. Stable carbon isotope analysis of breath samples was used to show that A. marlothii nectar is a readily available income energy source for nectar-feeding birds. Because A. marlothii nectar is so dilute we expected it to be an important water source for many opportunistic nectar-feeding bird species. There was no correlation between the enrichment of δ13C of breath CO2 (representing metabolised nectar sugars) and the δ18O in breath CO2 (representing a highly evaporated water source in nectar); for most birds the δ18O in breath CO2 was more similar to that of free-standing water sources. However, because our knowledge on the relationship between δ18O of ingested water and body water, and fractionation processes when CO2 is exhaled is limited, we were unable to quantify water obtained from nectar. The sugars of A. marlothii nectar are probably more important, as a food source for opportunistic nectarivores during dry winter months when insect abundance is low, than the water in nectar, because birds are able to source water from other drinking sites. / Thesis (PhD)--University of Pretoria, 2010. / Zoology and Entomology / unrestricted
206

Darkness

Green, Daniel R, Green, Daniel Read 20 December 2019 (has links)
During the long, dark night of a volcanic winter, a young man clashes with his father over the fate of five desperate survivors who have arrived outside the gates of the family compound. Yet he soon discovers true darkness lies within.
207

Commercialiser la nature et les façons d'être : une histoire sociale et environnementale de l'économie et de l'aménagement touristiques (Pyrénées françaises et espagnoles XIXe-XXe siécle) / Market tourism and lifestyles : a social and environmental history of tourist economy and planning (french and spanish Pyrenees, XIXth-XXth centuries)

Hagimont, Steve 25 November 2017 (has links)
L'objet de ce travail est d'examiner l'appropriation locale d'un changement global d'imaginaire, qui transforme les montagnes, leur environnement et leurs sociétés en objets de désirs et de consommations touristiques. Cette étude s'inscrit dans le temps long (entre la fin du XVIIIe siècle et la fin du XXe) et s'appuie sur un espace pionnier du tourisme européen. La mise en tourisme d'éléments de l'environnement (paysages, eaux, biosphère, climat, neige) et de certains modes de vie, place quelques territoires de montagne au cœur d'un mouvement économique, social et culturel éminemment contemporain. Le tourisme, dont l'apparition est concomitante de l'industrialisation, s'impose comme une forme de compensation face aux « débordements » industriels et urbains, comme un complément indispensable de la modernisation. Il connaît des taux de croissance forts qui en font un secteur à part entière de l'économie contemporaine. À chaque moment de cette histoire, certaines régions des Pyrénées s'illustrent au meilleur niveau d'équipement et de réputation et permettent d'interroger sur le temps long les problématiques posées par l'aménagement en montagne. Dans ces Pyrénées, le secteur touristique se construit d'abord localement, au contact des désirs des visiteurs. L'intervention publique est déterminante : des communes aménagent et expérimentent des modes de gestion de biens productifs (thermes, casinos, stations de ski). Elles sont appuyées par les préfectures et les administrations déconcentrées. L'État en tant que tel n'intervient, lui, que tardivement. Cette étude comparative et transfrontalière permet sinon de mettre en lumière des facteurs qui influent sur la trajectoire des aires et stations touristiques, qu'il s'agisse de thermalisme, d'excursions en montagne ou de sports d'hiver. Un exemple, celui de la station en site vierge de Superbagnères, invite en particulier à reconsidérer l'histoire traditionnellement faite des aménagements touristiques hivernaux. Cette recherche tente par ailleurs d'appliquer le concept d'hétérotopie, cette utopie effectivement réalisée, au tourisme ; elle interroge pour ce faire le versant social de l'aménagement, qui doit assurer le bon ordre et la sécurité dans les stations. Les effets du tourisme sur l'environnement sont également abordés : très tôt, les urbanisations accroissent l'exposition aux risques naturels, artificialisent les sols, posent des problèmes d'assainissement, tandis que les excursions et les consommations diverses augmentent la pression sur la biosphère. Cette étude s'intéresse aussi au partage de l'espace et aux conflits d'usage avec l'industrie et l'agriculture ; elle met en avant leurs liens avec la protection de la nature. Elle restitue, enfin, l'importance de la frontière et de l'imaginaire géographique dans les trajectoires économiques et touristiques. / The aim of this work is to consider the local appropriation of a global change of imaginary, which transforms the mountains, their environment and their societies into objects of touristic desires and consumables since the eighteenth century. This study examines a long period of time (between the end of the 18th century and the end of the 20th century) and draws on a pioneering area regarding European tourism (French and Spanish Pyrenees). The touristic transformation of environmental elements (landscapes, waters, biosphere, climate, snow) and specific lifestyles puts some mountain spaces at the core of a highly contemporary economic, social and cultural movement. Tourism, which emergence coincides with industrialization, appears as a form of compensation for industrial and urban "overflows" and as an essential complement to modernization. Its strong growth rates make it a full-fledged sector of the contemporary economy. All along this history, some regions of the Pyrenees reach the best level of equipment and reputation.
208

An exploratory study of winter road maintenance and the use of vehicle data / En forskningsstudie om vinterväghållning och användningen av fordonsdata

Rashid, Arin January 2021 (has links)
The Swedish road network is maintained by the Swedish Transport Administration, municipalities, and entrepreneurs with the goal of keeping the roads in satisfactory condition for traffic. The road operators are responsible for different roads and have several legislations that regulate construction and operation. One important aspect of winter road maintenance is the monitoring of the road situation ahead in order to call out resources for preventive measures. This study is performed at the company NIRA Dynamics with the purpose of going towards more digitized winter road information. The study explores different winter maintenance organizations in Sweden, investigates the importance of the information needed to be able to detect when roads are deemed too risky, and tries to gain an understanding of how the vehicle data provided by NIRA Dynamics best can provide a service for the winter road maintainers. This study is based on eight semi-structured interviews, user-tests aswell as a literature study. The findings of the study show that different winter maintenance organizations can differ a lot depending on the size and governing policies of the municipalities or entrepreneurs. The main differences can be found in their requirements and their method of monitoring the road situation ahead. The findings also show that the vehicle data is promising and has the potential to optimize and improve the overall winter maintenance planning. However, implementing and understanding the vehicle data in a real-world context requires collaboration from the different organizations to fulfill its value.
209

The role of mesoscale processes controlling physical and biological variability in the oligotrophic Central Red Sea

Zarokanellos, Nikolaos 05 1900 (has links)
The existing observations and model simulations indicate that mesoscale eddies and the Eastern Boundary Current (EBC) have a significant role in the complex circulation of the Red Sea. However, a full understanding of the processes that contribute to the physics and biological responses of the central Red Sea (CRS) has been limited due to the lack of sustained in-situ observations. In this dissertation study, in-situ observations extending over a thirty-three month period from spring 2013 through winter 2015 include an intensive ship-based and glider monitoring program to understand the key dynamic features of the CRS circulation. Nine glider missions and five ship-based surveys provide concrete resolution of both spatial and temporal variability in the CRS. The quasicontinuous glider observations resolve the influence of distinct water masses with a different origin that is present in the study area. Our results show that mesoscale eddies and the an intrusion of Gulf of Aden water governs the physical and biochemical characteristics of the CRS during the winter to summer transition period in 2013. During this period, an anticyclonic eddy appears to redirect the northward flow along the eastern boundary. Ship-based observations in fall 2013 indicate that the EBC can periodically transport patches of less salty and warmer water containing higher chlorophyll concentrations from south into the CRS. During spring 2014, ship observations show the presence of a cyclonic/anticyclonic eddy pair. The cyclonic eddy contribute an upward nutrient flux, resulting in an increase integrated chlorophyll concentration within the eddy. Higher chlorophyll and CDOM concentrations and lower N:P ratios characterized the inflow of lower salinity Gulf of Aden water from the south. To understand better how the mesoscale eddy activity, stratification, and the EBC modulate the nutrient availability and planktonic food web architecture in Red Sea two addition hydrographic surveys with plankton sampling were conducted in fall 2014 and spring 2015. The seasonal availability of Gulf of Aden water, stratification and eddies exerted a demonstrable effect on the plankton community by modulating the availability and utilization of allochthonous vs. autochthonous macronutrients by phytoplankton. Strong stratification, higher temperatures and depletion of nutrients by phytoplankton, subjected the plankton community to an overall nitrogen and phosphorus deficit in fall. To evaluate the role of the winter mixing, mesoscale eddies, and EBC within CRS during the winter to spring period, a sustained glider study (~91 days) was initiated from December 2014 to March 2015. Glider observations show the seasonal contrasts and transitions from strong summer stratification to winter mixing, with a corresponding transition from a well defined deep chlorophyll maximum to phytoplankton population intrusions of lower salinity water from the Gulf of Aden contributed to both the physical and biochemical variability within the region. Both GASW and GAIW can be entrained and diverted across the basin by larger eddies. Eddies play a role in the mixing between warmer, fresher water from the Gulf of Aden, and cooler, saltier water from the northern Red Sea.
210

Faktory ovlivňující potravní preference ptáků v zimě / Factors affecting food choices by birds in winter

Korencová, Petra January 2010 (has links)
I studied food choices of four small passerine species in winter on an artifical source of food, a bird feeder. I did experiments with two different types of food. I proposed that birds would prefer the type of food with higher contain of fat and calories. Food preferences were shown, but independently on calories contain. Greenfinches always selected sunflower seeds. I conclude, this species is affected by tradition, because it is usually fed by sunflower seeds in all bird feeders in vicinity of experimental location. In the second series of experiments I presumed the birds would prefer the food of bigger size because of easier manipulation on a potentially dangerous spot, which bird feeder represents. Again, the choices of greenfinches and field sparrows were not affected by this factor. Great tits did not prefer any food type. Siskins on the other hand prefered smaller food type, apparently because of its better accessibility using their small beaks. In the third series of experiments I tested the effect of presence of a stuffed predator - a sparrowhawk. I presumed it would lower food selectivity in this dangerous situation. The birds visited the bird feeder significantly less fraquently than in the absence of predator, but the food choices were not affected.

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