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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.
151

Cold tolerance of terrestrial isopod / Cold tolerance of terrestrial isopod

SOUČKOVÁ, Kateřina January 2008 (has links)
The woodlice, Porcellio scaber (Latreille, 1804), is a terrestrial isopod. Its metabolic reserves and body size are important factors affecting the fitness attributes, such as survival at unfavourable conditions. The larger and heavier individuals did not survive longer than smaller individuals. Amount of glycogen and body weight (fresh and dry) appeared to be an inapplicable parameter in the observed differences among individuals during survival at low temperature. We compared three treatments (long day, short day, natural autumn conditions) of Porcellio scaber and found differences in amount of energy reserves and cryoprotectants.
152

Trends in large carnivore diets in the Addo Elephant National Park, South Africa

Wentworth, Julia Claire January 2013 (has links)
Determining carnivore diets and how they may change over time is important if the management of large carnivores is successful in an enclosed reserve. Carnivore diets are known to shift over time in response to a variety of factors. These factors include prey availability and climatic conditions (rainfall patterns). The re-introduction of lions (Panthera leo) and spotted hyaena (Crocuta crocuta) to Addo Elephant National Park (AENP), South Africa provided the opportunity to study diet trends of lions and spotted hyaena in an enclosed system. The study focused on the diets and overlap of lions and spotted hyaena and how their prey selection changed since their re-introduction in 2003 to 2010. The database included scats collected over a seven year period. A total of 195 spotted hyaena scats and 217 lion scats were analysed using scat analysis. Prey items estimated from scat samples were coupled with prey availabilities to determine preferred prey items. Additionally, from determined carnivore diets, lions and spotted hyaena diet overlap was estimated over time. Lions preferred prey items which included zebra (Equus quagga) and eland (Tragelaphus oryx) during the early portion of the study. Over time preference shifted to include buffalo (Syncerus caffer), bushbuck (Tragelaphus scriptus) and grey duiker (Sylvicapra grimmia). Spotted hyaena preferred zebra and eland in the earlier part of the study, then over time, shifting their selection to grey duiker, buffalo, red hartebeest (Alcephalus busephalus) and bushbuck. Lions and spotted hyaena had a similar diet which increased in overlap during the study (67 percentage - 91 percentage). Our findings suggest that lions and spotted hyaena had a degree of diet specialization; both carnivores avoided and preferred certain prey items relative to their abundance. Their preference excluded the most abundant prey items, thus causing a decline in abundance of rarer species over time. Lions and spotted hyaena did not respond by shifting their diets to consume abundant prey items when their preferred prey items declined in availability. However, this study may be a snap-shot of carnivore’s diet trends. Thus further monitoring of the large carnivore diets should be researched in order to determine which factors drive their prey selection. Additionally, lions and spotted hyaena diet overlap increased overtime. The high diet overlap may be a result from spotted hyaena scavenging off lion kills, thus spotted hyaena diets may be facilitated by lion kills. Finally our data suggests that re-introduced large carnivores in AENP are likely to change the composition of the overall mammal community, potentially eliminating rare but preferred prey species in an enclosed reserve.
153

Small camera aerial photography in forest and wildland recreation

Turner, Melvin Howard January 1972 (has links)
This thesis traces the acquisition and potential applications of 35 mm aerial photography as a tool in helping to make decisions in the allocation of land to forest recreation. The advantages of the 35 mm aerial system, including its versatility, simplicity, applicability, and relatively low cost, were tested and applied to the field of forest and wildland recreation. Dealing first with the technology and equipment available, methods of acquiring the imagery were investigated, experimented with, and adopted. Then, working with the results of eleven hours of flying time, photogrammetric and photointerpretive techniques were applied to the reflected attributes of the physiographic, edaphic, hydrologic, and vegetative environments. In addition, the use of the system was investigated for recording recreational use on existing sites. The 35 mm aerial system can help identify those attributes of the land important to forest recreation. In addition it has benefit in the closely related fields of archaeology, protection, and wildlife and in evaluating hazard potential. Used in conjunction with either the small scale imagery soon becoming available through the Earth Resources Technology Satellite Program or existing air photos, the 35 mm system can accurately capture and monitor changes in the natural and artificial environments at a relatively low cost and assist the forest manager in decisions relating to the allocation of forest land to recreational use. / Forestry, Faculty of / Graduate
154

Mobilização de reservas durante a germinação e estabelecimento plântulas de Macrolobium acaciifolium Benth. (Leguminosae) e seu papel na adaptação aos pulsos de alagamento na Amazônia / Storage mobilization during germination and seedling establishment of Macrolobium acaciifolium Benth. (Leguminosae) and its role on the adaptation to the inundation pulses in the Amazon

Rayane de Tasso Moreira Ribeiro 08 April 2014 (has links)
Planícies amazônicas alagáveis apresentam espécies arbóreas que estão sujeitas a um pulso de inundação proveniente das chuvas anuais. Muitas destas espécies apresentam estratégias de adaptação ao alagamento, germinando suas sementes e estabelecendo as plântulas antes do próximo período de cheia. Este é o caso de Macrolobium acaciifolium (Benth) Leguminosae (Caesalpinoideae), que ocorre nas cotas altitudinais mais altas das várzeas e igapós amazônicos. Neste trabalho, pela primeira vez foi caracterizado o sistema de mobilização de reservas ao longo do período de germinação e estabelecimento das plântulas de M. acaciifolium, com o objetivo de compreender os mecanismos fisiológicos e bioquímicos relacionados à sua estratégia em face à inundação. O experimento teve duração de 56 dias, nos quais foram realizadas coletas destrutivas e análises não-destrutivas de sementes e de diferentes partes das plântulas para análises de crescimento, fotossíntese, carboidratos não estruturais (frutose, glucose, sacarose e amido), xiloglucano de reserva e análises citoquímicas correspondentes à detecção de proteínas, amido e xiloglucano de reserva. Após análises citoquímicas e de açúcares, é reportado pela primeira vez na literatura científica, a existência de uma semente que acumula simultaneamente amido e xiloglucano de reserva na parede celular. Não foi observada a presença de corpos protéicos, que é uma característica comum de armazenamento de nitrogênio em sementes de Leguminosae, o que indica que a plântula provavelmente estabelece a assimilação de nitrogênio pelas raízes ao invés de armazenar e mobilizar reservas para isto. Nas sementes de M.acaciifolium xiloglucano e amido juntos perfazem 21,6% da massa da semente quiescente. No início da germinação, parte do amido é degradado e há um aumento concomitante de xiloglucano que leva a um equilíbrio entre as duas reservas. Dos 10 aos 14 dias após a embebição (DAE), o amido dos cotilédones é exaurido com concomitante desenvolvimento das raízes e do caule das plântulas. A partir de 20 DAE, o xiloglucano passa a ser degradado e a mobilização ocorre sem alterações na estrutura do polissacarídeo na parede celular e simultâneo acúmulo transitório de galactose, glucose, xilose e amido. Os produtos de degradação do xiloglucano levam à produção de folhas e ao estabelecimento da fotossíntese. As observações feitas neste trabalho sugerem que M. acaciifolium apresenta mecanismos de adaptação aos pulsos de inundação da Amazônia durante o processo de germinação e estabelecimento das plântulas / The Amazonian floodplains display tree species that are subjected to yearly inundation pulses. Several of these species colonize these regions are well adapted to the flood pulses, germinating their seeds and establishing seedlings before the next pulse comes. This is the case of Macrolobium acaciifolium (Benth) Leguminosae (Caesalpinoideae) that occur in the upper part of the riverbanks of the amazonian várzeas and igapós. In the present work, we characterized for the first time the system of storage mobilization along the period of seed germination and seedling establishment with the objective of understanding the physiological and biochemical mechanisms related to the strategy of M. Acaciifolim to face the next flooding season. The experiment was performed for 56 days in which destructive and non-destructive analyses of the seed and different parts of seedlings were performed for analyses of growth, photosynthesis, non-structural carbohydrates (fructose, glucose, sucrose, raffinose and starch), storage xyloglucan and corresponding cytochemical analyses to detect proteins, starch and storage xyloglucan in cotyledon tissues. After cytochemical and sugar analyses, it is reported for the first time in scientific literature the existence of a seed that accumulates starch and storage xyloglucan on the cell wall simultaneously. The presence of protein bodies, a common feature of seeds of the Leguminosae, was not observed, indicating that seedlings probably establish nitrogen assimilation very quickly through the newly formed roots instead of using a storage mobilization system for this reserve type. In seeds of M. Acaciifolium starch and xyloglucan correspond to 21,6% of the quiescent seed mass. At the beginning of germination, some starch is degraded with a concomitant increase in storage xyloglucan so that the yields of the two polymers become equal. From 10 to 14 days after imbibition (DAI), all starch is mobilized to support root and stem growth. From 20 DAI, xyloglucan is completely degraded without changes in its structure and with transient accumulation of galactose, glucose, xylose and starch. The products of degradation of storage xyloglucan lead to the production of leaves and photosynthesis establishment. The observations made in this work suggest that M. Acaciifolium show unique mechanisms of adaptation to the inundation pulses in the Amazon during the germination and seedlings establishment
155

Optimized Method of Estimating Mineral Reserves Using the O'Hara Mathematical Model for Underground Mining in Peru

Torres-Sanchez, V., Torres-Sanchez, V., Olivas-Maldonado, P., Diaz-Huaina, G., Raymundo-Ibanez, C., Perez, Moises 28 February 2020 (has links)
Peru / This research project is aimed at applying the proposed methodology to optimize the calculation of mining reserves using an empirical relationship for dilution, as proposed by O'Hara. This methodology uses three key parameters: dilution, mineral value, and total costs. In general, costs include mining costs, processing within plants, and administrative expenses related to producing a mineralized block. Similarly, to calculate the mineral value, studies on changes in mineral prices over the last 30 years were included to provide more representative values. The research was applied to mineralized block number 1000, which yielded positive results since dilution could be easily calculated using three key parameters: operating method, dip, and vein width. The dilution value of 12.25% was valid, as it was within the range of 10% to 23%. This range was considered based on other studies that apply this operating method. Then, the methodology was analyzed in three more settings, each represented by a mineralized block. The blocks assessed were 1001, 1002, and 1003, and the results indicated that the dilution found was acceptable at values of 18%, 19%, and 22%, respectively.
156

A Characterization and Determination of the Coal Reserves and Resources of Southwest Virginia

Westman, Erik C. 27 April 1999 (has links)
Coal mining and timber are the two primary industries supporting the people of Southwest Virginia. Coal mining has occurred for more than 100 years, but production has dropped since reaching a peak in 1990. In order to properly plan with remaining coal production a study was conducted to characterize and estimate coal resources. Seam thickness was found to be the parameter which most influenced resource levels. An economic model was developed to determine which portion of the reserves could economically be extracted. It was found that 3.95 billion tons, or 14% of the remaining resource, is economic under current mining conditions. More than 60% of these reserves, however, are in deep seams which require shafts to be constructed prior to initiation of mining. / Ph. D.
157

ESTIMATION OF AGGREGATE RESERVES IN OHIO

Mahmoud, Khaled 07 May 2022 (has links)
No description available.
158

Globalization of financial markets and the demand for international reserves : the case of the industrialized countries

Ganguli, Alakananda January 1994 (has links)
No description available.
159

A study of the town forest of Russell, Massachusetts, with particular reference to the economic, educational, and recreational aspects.

Pullman, John S. 01 January 1952 (has links) (PDF)
No description available.
160

Macroeconomic Indicators as Determinants of the U.S. Dollar as a Primary Reserve Currency

Salgado, Joel 01 May 2015 (has links)
Several currencies have arisen as credible competitors for the dollar's primary reserve currency position in central banks around the globe, and many wonder how long the dollar can maintain its position. Reserve currency usage is dependent relative to the size of the home economy, openness to trade, and prosperous and stable growth, including an inertial bias. This paper utilizes econometric methods to examine the significance of macroeconomic indicators of the U.S. dollar’s reserve currency status. The dataset is gathered from the IMF's COFER database using a time period from 2000 to 2013 in order to capture the most relevant reserve levels post-euro adoption. The estimated coefficient values indicate a significant inertial bias. This result implies that we can expect the dollar to hold the primary reserve currency position for the near future.

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