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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.
111

Ecology and morphology of the Kalahari tent tortoise, Psammobates oculifer, in a semi-arid environment

Keswick, Tobias January 2012 (has links)
Philosophiae Doctor - PhD (Biodiversity and Conservation Biology) / Southern Africa harbours one-third of the world's Testudinid species, many of which inhabit arid or semi-arid areas, but ecological information on these species is scant. I studied the habitat, morphology and ecology of Kalahari tent tortoises over 13 months in semi-arid Savanna at Benfontein farm, Northern Cape Province, South Africa. In order to allow continuous monitoring of individuals, I attached radiotransmitters to males and females, split equally between two habitats, sites E (east) and W (west), with apparent differences in vegetation structure. Results of the study were based on data obtained from 27 telemetered tortoises and 161 individuals encountered opportunistically. Female Kalahari tent tortoises were larger than males and the sex ratio did not differ from 1:1. Based on person-hours to capture tortoises, the population appeared to have a low density, with more time required to capture a juvenile (35 hours) than an adult (10-11 hours). The frequency distribution of body size ranges was indicative of recruitment. Relative age, based on annuli counts, suggested that males were younger than females, perhaps because males as the smaller sex are more predation-prone than females. Linear relationships between annuli counts and shell volume indicated that, after reaching sexual maturity, female body size increased faster in volume than did male body size, possibly because a larger volume may enhance female reproductive success. Body condition differed between sites, sexes and among seasons. The hot and dry summer may account for low summer body condition, whereas vegetation differences and size effects, respectively, may account for the low body condition of tortoises in site W and in males. Site E was sandy with grasses, particularly Schmidtia pappophoroides, being the prevalent growth form. This habitat resembled a Savanna vegetation type Schmidtia pappophoroides – Acacia erioloba described for a neighbouring reserve. Site W was stonier, dominated by shrubs, and was reminiscent of Northern Upper Karoo vegetation (NKu3). Neither site resembled Kimberley Thornveld (SVk4), the designated vegetation type of the area. Differences in substrate and grazing intensity may have contributed to site vegetation differences. Rainfall had an important influence on seasonal vegetation. Short grass abundance correlated with rainfall and annual plants sprouted after spring rain. Refuge use changed according to season and sex. Males selected denser refuges than females did, perhaps because males were smaller and more vulnerable to predation and solar heat. Tortoises selected sparse, short grass as refuges in cool months, probably to maximise basking whilst remaining in protective cover. During hot periods, mammal burrows were preferred to vegetation as refugia. The smaller males spent more time in cover than females, which may be related to predator avoidance or thermoregulation. Females spent more time basking than males, perhaps due to their larger size and to facilitate reproductive processes. Tortoises did not brumate, but through a combination of basking, and orientation relative to the sun in their refuges, managed to attain body temperatures that allowed small bouts of activity. Body temperature for active tortoises was similar among seasons, and was higher for more specialised active behaviours, such as feeding and socialising, than for walking. Increased activity by males in spring could relate to mating behaviour while females were more active in autumn, when they foraged more than males, perhaps due to the high cost of seasonal reproductive requirements. Males displaced further per day than did females, but home range estimates did not differ between sexes. Annual home range estimates varied substantially among individuals: 0.7–306 ha for minimum convex polygons and 0.7–181 ha for 95% fixed kernel estimates. The ability to cover large areas would assist tortoises in finding resources, e.g., food, in an area where resource distribution may be patchy. Differences among seasonal home ranges and movements probably reflect seasonal climatic change; activity areas shrinking when temperatures were extreme. In order to assess the effects of a semi-arid environment on the morphology of P. oculifer, I compared its morphology to that of its ‘cool-adapted’ sister taxon Psammobates geometricus, using live and museum specimens. Both P. oculifer and P. geometricus are sexually dimorphic and differences between the two species could indicate environmental or sexual selection effects, or a combination of the two. The shorter bridge length, which allowed more leg space, and wider front feet in P. oculifer cohorts probably represent traits for manoeuvring in a sandy habitat, while wider heads in P. oculifer possibly relate to interspecific differences in diet. The flatter shell in female P. oculifer, relative to P. geometricus, may represent a trade-off between space for reproductive structures, e.g., eggs, and the need to fit into small refuges, e.g., mammal burrows. Male P. oculifer had wider shells, more space around their hind legs, and wider hind feet than P. geometricus males had, all characteristics which may assist males to fight and mate in a sandy environment. / South Africa
112

"Oft Have I Heard of Sanctuary Men": Fictions of Refuge in Early Shakespeare

Woodring, Benjamin Michael January 2014 (has links)
This study weaves together several strands of inquiry. On the level of dramatic analysis, I look to understand how "sanctuary" spaces operate in Shakespeare's early plays and the ways in which such zones relate to genre. In tragedy, there is no escape valve, no place for retreat. The aesthetic depends on the increasing pressure and the gradual winnowing of options and possibilities. I analyze Richard III (both Thomas More's and Shakespeare's) as the preeminent example of sanctuary-breaking and generic claustrophobia. In Shakespearean comedy, on the other hand, sanctuaries allow action to continue, brokering resolutions while avoiding tragic termination. In this vein I consider The Comedy of Errors and As You Like It. The second strand is historical: I attempt to situate the plays within the larger context of England’s immunity spaces in their twilight. I document the upheaval and confusion regarding refuge sites following the Reformation and the dissolution of the monasteries, contending that the conflicting swirl of concepts surrounding Elizabethan sanctuary – as something both holy and debauched – made it ripe for Shakespeare’s fascination. Finally, in the epilogue I offer a more theoretical reading of sanctuary practices over time, arguing that asylum is often a tool for young or relatively unstable governments to get subjects to present themselves. In this view, sanctuaries are not exceptional spaces outside diurnal affairs and authority, but rather the precise cohesive principle that keeps a fledgling jurisdictional structure intact. Nevertheless, I argue that alternative modes of access to the tools of the administrative culture within which one is unavoidably entrenched may ultimately be more profound than the utopian wish for escape.
113

Why large homes are restricting : Framing personal space: vulnerability and volatility

Niklasson, Elias January 2022 (has links)
Personal space is a spatial privacy layer that regulates access to the self, without it our ability to function properly is impaired. An attack on the personal space is an attack on the person itself. Thus, personal space can be seen as a part of the self. The environment can be a part of personal space and therefore also seen as part of the self. Personal space, as the direct space surrounding the body, is framing the conscious experience of self. Due to its abstract nature, it is more appropriate to impact that experience by framing personal space through the environment. How to bridge something that fleeting with something so concreate is not obvious. This thesis tries to find a useful methodology for this through available research, own experiments, and discussion. Theories about stimulation, affordance theory, and prospect refuge theory, seems to together capture the whole quite well into something more tangible. The experience of personal space is concluded to be too ambiguous to properly design around and letting the user regulate it themselves by moving through a dynamic environment seems more fruitful. Ambient factors impact the need of personal space but the thresholds between spaces are where dynamics of the larger environment is concentrated. Therefore, they are more decisive in framing personal space and the architect’s attention should arguably be directed towards these.
114

Admissible height and urban density of buildings for the Prospective Management of Seismic Risk in residential areas

Herrera, Fabiola, Mamani, Flaby, Arana, Victor 30 September 2020 (has links)
El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / This research proposes limit values of height and population density of buildings for a Prospective Management of Seismic Risk in residential areas. The analysis of an efficient evacuation of buildings to the street or refuge area was carried out, evaluating human behavior with models based on the agent, the influence of buildings and the urban parameters of the city with three-dimensional models (BIM) for a severe seismic scenario. The present article establishes that the maximum permissible height of buildings projected in a residential avenue is directly related to the width of the available refuge zone to guarantee the correct evacuation of said zone during a severe seismic event. In addition, an evaluation of a real existing scenario is made in a section of a residential avenue.
115

The Influence of Predator Exclosures and Livestock Grazing on Duck Production at Bear River Migratory Bird Refuge, Utah

West, Benjamin C. 01 May 2002 (has links)
Nest predation is a major factor impacting duck production and recruitment on breeding areas in North America. I surveyed waterfowl managers employed by the U.S. Fish and Wildlife Service and U.S. state wildlife agencies to determine their beliefs about nest predation and its management. Over 64% of respondents believed that rates of nest success on their management units averaged <30% between 1996-2000. Managers believed habitat management and direct predator control were the most effective techniques to reduce nest predation. The construction of predator exclosures around nesting habitat also has been recommended to reduce nest predation. Between 1999-2001, I evaluated the effectiveness of 4 predator exclosures to enhance duck nest success at Bear River Migratory Bird Refuge, Utah. During this period, rates of nest success in the exclosures were slightly higher than that within control plots, but still <15%. Although published guidelines commonly recommended predator fences ≤ 117 cm in height, I observed red foxes jump the 114-cm-high fences. Additional research is needed to identify effective predator fence designs. Wildlife managers have argued that periodic disturbance of vegetation should be a component of management on waterfowl breeding areas. Although many techniques are available to manipulate vegetation, grazing by domestic livestock has been controversial. Some researchers have reported that livestock grazing is detrimental to nesting ducks whereas others have argued that it can be beneficial. I evaluated the impact of a short-duration, high-intensity winter livestock grazing program on duck nesting at Bear River Migratory Bird Refuge. Following a winter grazing treatment, I measured visual obstruction on both grazed and ungrazed plots during the spring nesting season. Although visual obstruction readings on grazed plots were lower than those on rested sites early in the nesting season, those differences diminished as the season progressed. Winter grazing may impact early-nesting ducks like mallards (Anas platyrhynchos), but not late-nesting species like cinnamon teal (Anas cyanoptera) and gadwall (Anas strepera). In designing grazing programs to manage nesting cover, managers should consider their waterfowl production goals, the composition of breeding duck populations, type of grazing system, and climatic conditions.
116

The Foods and Feeding Habits of Botulism Intoxicated and Healthy Waterbirds on the Bear River Refuge, Utah, with Emphasis on the American Avocet and Blacknecked Stilt

Wilson, George W. 01 May 1973 (has links)
Primary objectives of this study were: (1) to compare the food habits of healthy and botulism intoxicated American avocets and blacknecked stilts for qualitative and quantitative differences, (2) to determine .which invertebrates found in the tracts of intoxicated and healthy birds contained type C toxin, and (3) to explain apparent susceptibilities among different sexes, ages and species of birds. Based on percent utilization and occurrence of food items in the esophagus , the diets of healthy and intoxicated birds were similar. However, intoxicated avocets consumed higher proportions of Gastropoda and intoxicated stilts more Hydrophilidae larvae than did healthy birds. Because of similarities in diets of healthy and intoxicated birds, birds probably became intoxicated from eating randomly toxic foods and not because of differences in diet or food preference. Examinations of esophageal contents of avocets and stilts better described recently consumed food items than did examinations of gizzard contents. Soft-bodied invertebrates were rendered unidentifiable in the gizzard. The esophageal contents of juvenile avocets and stilts contained greater proportions of animal matter than did those of adults. Only three of 86 food samples analyzed were definitely positive for type C botulism toxin. These were: one sample of Tendipedidae larvae and two of pooled gizzard contents which included fragments of Corixidae, Hydrophilidae adults, seeds and vegetative fibers. Only three of 86 food samples analyzed were definitely positive for type C botulism toxin. These were: one sample of Tendipedidae larvae and two of pooled gizzard contents which included fragments of Corixidae, Hydrophilidae adults, seeds and vegetative fibers.
117

Seasonal Utilization of Sago Pondweed by Waterfowl at Bear River Migratory Bird Refuge, Utah

Sterling, Michael R. 01 May 1970 (has links)
Seasonal utilization of sago pondweed (Potamogeton pectinatus L.) by waterfowl was studied at Bear River Miqratory Bird Refuge by comparing amounts of sago production on a series of plots on Unit Four. One plot was available to carp and waterfowl; one only to carp; and one available to neither. The cage used to eliminate carp and waterfowl use of a plot caused a significant increase in sago production. The increase was attributed to less turbidity and less wind and wave action within the cage. Carp distribution was limited to deep-water portions of Unit Four, a small area, and they had no significant effect on sago production. Therefore, sago production from carp and open plots was compared to determine utilization of sago by waterfowl. Waterfowl utilization of sago in summer and spring was not significant; however, 52 percent of the tuber crop was used by waterfowl in fall. The method of study did not allow detection of waterfowl use of windrowed or submersed seed. Water depths between 2 and 10 inches had little or no effect on waterfowl use of tubers in fall; however depths between 5 and 14 inches in spring and 4 and 13 inches in summer may have prevented full use of tubers. Tubers were most available to ducks in the first 6 inches of soil but were utili zed to 8 inch depths. A series of 50 foot-square pens (2,500 square feet) were stocked with semi-domestic mallards to determine the effect of certain levels of utilization on sago growth. Sago seemed to recover well after heavy spring utilization. Results concerning the effect of summer utilization on production were not conclusive. Sago recovered well in spring after waterfowl had consumed 52 percent of the tuber crop the previous fall.
118

Can Twilight Reefs Usher In A New Dawn For Depauperate Shallow Coral Reefs?

Noren, Hunter KG 21 July 2016 (has links)
As shallow reefs continue to decline, scientists are searching for the key to their persistence; as it turns out, they may just need to look deeper. Below many shallow tropical reefs, there exist healthy and more stable mesophotic coral reef communities. The ability of these reefs to act as a refuge for declining shallow populations has garnered significant interest among the scientific community; however, the reproductive and larval aspects necessary for this to occur are unknown. This study assesses the ability of deep reefs to act as a reproductive refuge for shallow counterparts by examining gametic compatibility, viability and larval settlement preferences. Gametes from Orbicella franksi inhabiting the shallow (14-20m) and the upper mesophotic (27-32m) were introduced in a series of inter- and intra-depth crosses and found to be compatible. Larval settlement experiments found no natal depth preference, with deep larvae significantly preferring to settle on shallow conditioned substrate. Our findings support the plausibility of healthy mesophotic reefs acting as a refuge for depauperate shallow populations by (1) providing gametes to mix with limited shallow gametes resulting in increased fertilization and (2) providing larvae that recruit and repopulate shallow reefs. This is the first study to comprehensively evaluate the Deep Reef Refugia Hypothesis from a reproductive and larval settlement standpoint. Our results suggest a close coupling between shallow and mesophotic reefs through gamete and larval export and illustrate the current and future importance of these mesophotic reefs.
119

Avian Affairs: A Study of the Occurrence and Benefits of Extra-pair Breeding Behavior in Eastern Kingbirds (Tyrannus Tyrannus)

Dolan, Amy Catherine 01 June 2006 (has links)
Over three consecutive breeding seasons I examined the breeding system of Eastern Kingbirds in Malheur National Wildlife Refuge in SE, Oregon. To assess genetic paternity, I optimized seven microsatellite markers and determined that extra pair paternity was common. Extra-pair young were present in approximately 60% of nests, representing 47% of young. I examined implications of extra-pair paternity from three perspectives. First, I examined the impact of extra-pair paternity on the opportunity for sexual selection within a socially monogamous system and identified correlates of male reproductive success. Some males were successful at the expense of others, and 24% of males did not sire any young. Thus, variance in male reproductive success was more than nine times greater than female variance, indicating that sexual selection operates strongly in this system. Extra-pair success was positively related to tarsus length and inversely dependent upon dawn song start time. Within-pair success was positively related to nest defense intensity during the incubation period. Second, I assessed the four genetic hypotheses proposed to explain female cooperation in extra-pair copulations. Extra-pair young were not distributed randomly among broods. Cuckolded within-pair males were not more closely related to females than were extra-pair sires. Pair wise comparisons indicated males with specific song and morphological traits were chosen as sires. Brood success (proportion of brood to fledge and recruit) was unrelated to thenumber of males who sired young in the brood. Extra-pair young were larger and heavier than their within-pair half-siblings. These results unambiguously support the 'good genes' hypothesis of female extra-pair mating. Last, I examined the influence of breeding date and parental condition (mother, social father and genetic sire) on offspring sex ratio. Given that male variance in reproductive success is much greater than that of females, I predicted the characters of genetic sires would be the most important factor influencing offspring sex ratio. Contrary to my prediction, male traits did not influence offspring sex ratio. However, more males hatched early in the season and females in better condition produced more sons. I also found that male nestling survival to the next breeding season was inversely related to date.
120

Skyddad plats : En studie i Danmark och Sveriges beredskap att ta emot fartyg i behov av assistans på skyddad plats / A study of Denmarks and Swedens preparedness for directing vessels in need of assistanne to a place of refuge.

Asplund Schmidt, Johan January 2022 (has links)
Rätten att söka nödhamn eller vad som i dag kallas för skyddad plats är en gammal traditionsenlig rätt inom sjöfarten. I flera fall där fartyg har sökt skydd i en hamn i modern tid har fartyg nekats. Till följd av Erika, Castor och Prestige incidenterna runt 2000 talet, som i två av fallen ledde till stora miljökatastrofer i form av oljeutsläpp, insåg man at något behövde göras. IMO författade sina riktlinjer och EU författade direktiv 2002/59/EG som behandlar mottagandet av fartyg i behov av assistans på skyddad plats. Skyddad plats definieras som en hamn, del av hamn eller annan skyddande kaj eller annat skyddat område, till exempel ankarplats, som kan användas för att ta emot fartyg i en nödsituation eller i behov av assistans. Syftet med detta arbete är att undersöka hur beredskapen ser ut i Sverige och Danmark för att ta emot fartyg på skyddad plats. Vilka myndigheter som ingår i organisationen, vilka beslutsunderlag som finns, vilka lagar och direktiv de har att förhålla sig till och vilka utsedda skyddade platser som finns i de bägge länderna. För att få svar på frågeställning har studien främst utförts genom litteraturstudie men även kvalitativ intervju har använts. Resultatet visar att det finns riktlinjer från IMO som inte är legalt bindande, men även EU direktiv som införlivats i de bägge ländernas nationella lagstiftning. EU har även material som är tänkt att underlätta för länderna att upprätta sina egna beredskapsplaner utefter direktiv 2002/59/EG. Det finns regionala samarbeten i form av HELCOM för Östersjöområdet och Bonnavtalet för Skagerrak och Nordsjön vilka främjar samarbetet vid miljöinsatser och därmed behandlar ämnet skyddad plats. Bägge länder har utpekade skyddade platser och en myndighetsstruktur för att ta emot fartyg på skyddad plats. Studien tyder på att det är en viktig men komplex fråga. Det är många olika myndigheter och intressenter som är involverade. Det är fortfarande ett pågående arbete där Sverige reviderar sina planer i nuläget. Ett aktuellt ämne verkar vara incidenter med HNS och ratificeringen av HNS konventionen. / The right to seek refuge in port is an old customary right in shipping. In several cases where ships have sought refuge in a port in modern times, ships have been denied. As a result of the Erika, Castor and Prestige incidents around the 21st century, which in two of the cases led to major environmental disasters in the form of oil spills, it was realized that something needed to be done. The IMO drafted its guidelines and EU-drafted Directive 2002/59/EC dealing with the reception of ships in a place of refuge. A place of refuge is defined as a port, part of port or other protective berth or other protected area, such as anchorage, which can be used to receive ships in an emergency or in need of assistance. The purpose of this work is to investigate the preparedness in Sweden and Denmark to receive ships in a place of refuge. which authorities are part of the organization, what decision-making documents exist, what laws and directives are in place and which places of refuge that have been designated in the two countries; In order to get answers to the questions, the study has mainly been carried out through a literature study, but qualitative interview have also been used. The results show that there are guidelines from the IMO that are not legally binding, but also EU directives transposed into the national law of the two countries. The EU also has material intended to facilitate countries to draw up their own contingency plans under Directive 2002/59/EC. Both countries have designated protected sites and a governement structure for receiving ships in a place of refuge but quite different approach. The study shows that it is an important but complex issue. There are many different authorities and stakeholders involved. It is still a work in progress where Sweden is revising its plans at the moment. One current topic seems to be incidents regarding Hazardous and Noxious Substances (HNS) and ratification of the HNS convention.

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