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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.
51

Responses to Soils and a Test for Preadaptation to Serpentine in Phacelia dubia (Hydrophyllaceae)

Taylor, Stacy I., Levy, Foster 01 September 2002 (has links)
Tests for adaptation to three different soils inhabited by subspecific taxa within Phacelia dubia and for preadaptation to a serpentine soil were conducted to examine the plausibility of an endemic-to-endemic evolutionary pathway. Each taxon performed optimally on its home soil, demonstrating edaphic specialization. None survived on the serpentine. Hydroponic assays for tolerance to two serpentine factors, elevated magnesium: calcium and elevated nickel, were conducted on population samples and maternal half sib families. Performance was estimated by root length and rosette diameter while leaf dissection served as an indicator of developmental maturity. Both nickel and magnesium: calcium of typical serpentine inhibited all three taxa. However, the granite outcrop endemic var. georgiana tolerated higher magnesium: calcium than other taxa, its tolerance exceeded that found on its home soil, and there was developmental variation among sibships. The tolerance uncovered in the endemic var. georgiana suggests that a specialized endemic taxon may encompass variation that could lead to preadaptation to a novel habitat and therefore serve as the raw material for speciation rather than represent an evolutionary dead end.
52

Endemic Whitefishes of Bear Lake, Utah-Idaho: A Problem in Systematics

White, Robert G. 01 May 1974 (has links)
The systematic status of whitefishes endemic to Bear lake, Utah-Idaho, has remained tenuous since their original description. Clarification of this problem was the major objective of the present study. The general approach was an integrated one, including examination of morphological, biochemical and ecological parameters; artificial hybrids were produced and compared with questionable groups from the natural population. Morphological analysis revealed five forms of Bear Lake whitefishes Prosopium gemmiferum (Bonneville cisco) and P. abyssicola (Bear lake whitefish) were well differentiated from other forms and were treated as originally described. The P. spilonotus (Bonneville whitefish) group, however, was found to be made up of two morphologically distinct populations, referred to as P. spilonotus (small form) and P. spilonotus (large form). The fifth group referred to as P. gemmiferum-like (represented by only five specimens) was intermediate between P. gemmiferum and either P. spilonotus (small form) or P. abyssicola and was hypothesized to be of hybrid origin. Multiple discriminant function analysis of the four major groups and P. williamsoni (mountain whitefish) (Logan River) confirmed morphological differentiation between forms. Hybridization studies among Bear Lake Prosopium and P. williamsoni involved 50 homo - and heterospecific crosses (17 combinations). Of 12 experimental hybrid combinations attempted, all those involving simultaneously ripe specimens of two groups (five crosses) showed maximum fertilization success equalling that of pure crosses. no evidence that interspecific crosses are less successful than conspecific crosses, with the possible exception of P. williamsoni ♀ x P. gemmiferum ♂ (W x G), was obtained. Culture methods were developed and morphological comparisons made. Origin of P. gemmiferum-like hybrids in the lake population was not consistently explained by morphological comparison of known P. spilonotus (small form) ♀ x P. gemmiferum ♂ (S x G) hybrids or P abyssicola ♀ x P. gemmiferum ♂ (A x G) hybrids; morphometric characters were more like S x G hybrids while meristic characters were more closely associated with A x G hybrids. Based on evidence available, no definitive statement could be made concerning the origin of P. gemmiferum-like hybrids except that they are hybrids among combinations of P. gemmiferum and either P. spilonotus (small form) or P. abyssicola. no known hybrid explained the origin of either group of P. spilonotus. Electrophoretic analysis of general proteins and several enzyme systems of various tissues showed much similarity among Bear Lake Prosopium; only P. williamsoni was totally unique. Biochemical evidence did not support or refute separate consideration of the two forms of P. spilonotus but did establish that neither were phenotypic variants of P. williamsoni. Ecological characteristics of Bear Lake Prosopium revealed important distinctions between forms. Growth histories of P. abyssicola, P. spilonotus (small form) and P. spilonotus (large form) showed pronounced differences. Distinct differences in growth and in age and size at maturity of forms of P.. spilonotus provided further evidence supporting their separate consideration. Spatial overlap of spawning activities was marked between forms of P. spilonotus and P. gemmiferum; P. abyssicola was well separated spatially. Temporally, slight overlap was observed between ripe females of one group and ripe males of the succeeding group to spawn. the only observation of the simultaneous occurrence of ripe females of two forms was between P. spilonotus (large form) and P. spilonotus (small form); in this instance, the number of ripe females of each form was extremely small. No evidence of mass hybridization among forms was observed. A combination of temporal, spatial and ethological premating isolating mechanisms are thought to be important in reproductive isolation of Bear lake whitefishes while postmating mechanisms are nonfunctional with the possible exception of hybrid sterility. Morphological and ecological analyses, combined with results of experimental hybridization, provided abundant evidence supporting separate recognition of the two forms of P,. spilonotus. Karyotypes of P. gemmiferum, P abyssicola and P. spilonotus (small form) have been determined (Booke, 1974) and are unique for each species. If the karyotype of P. spilonotus (large form) is found to also be unique, there should be no question that the two forms of P. spilonotus represent distinct species. Final clarification of the taxanomic status of these forms will not come until karyotype data is available; however, based upon present evidence, tentative recognition of a new species is recommended.
53

Natural History and Breeding System of Maguire Primrose

Davidson, Jacob B. 01 May 2010 (has links)
The goal of this thesis was to examine the breeding system and natural history of the Maguire primrose (Primula cusickiana var. maguirei). Maguire primrose is an endemic, threatened subspecies found only along a narrow corridor within Logan Canyon in northern Utah, USA. This plant displays distinct flower distyly, with clear distinction of pin and thrum morphologies (morphs). The timing of Maguire primrose flower blooms was disparate between upper and lower canyon populations, and the flowers experienced cool temperatures occasionally. I captured eight different species of flying insects visiting Maguire primrose flowers, and made 67 observations of insect visitation. Inter-morph outcrossing hand pollinations were the most successful hand pollinations performed, but were usually not as successful as those that were naturally pollinated. Selfing rates were quite low compared to outcrossing reproductive scenarios. Morph-specific fecundity differences were detected in my hand pollinations, but not in the naturally pollinated maternal plants. I did not observe clear fecundity differences based on the canyon location of Maguire primrose.
54

Evolutionary origins of the endemic ichthyofauna in Inle Lake, an ancient lake in Myanmar / ミャンマーの古代湖・インレー湖における固有淡水魚類の起源

Fuke, Yusuke 23 March 2023 (has links)
京都大学 / 新制・課程博士 / 博士(理学) / 甲第24456号 / 理博第4955号 / 新制||理||1707(附属図書館) / 京都大学大学院理学研究科生物科学専攻 / (主査)准教授 渡辺 勝敏, 教授 曽田 貞滋, 教授 中務 真人 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM
55

Blastomycosis in Northeast Tennessee

Vasquez, José E., Mehta, Jay B., Agrawal, Rajesh, Sarubbi, Felix A. 01 January 1998 (has links)
Study objectives: To study the epidemiologic and clinical features of blastomycosis in northeast Tennessee. Design: Retrospective review of blastomycosis cases in the region from 1980 through 1995. Setting: Hospitals located in the Tri-Cities region of northeast Tennessee. Patients: Seventy- two patients with confirmed blastomycosis infection. Interventions: None. Results: During the 1980 to 1995 study period, we documented 72 cases of blastomycosis. The mean age was 52 years (range, 13 to 86 years), most were male (69.4%), and nine were immunocompromised. A possible environmental exposure was noted for 28 patients. Pulmonary involvement represented the most common site of infection (61 cases), but multiorgan involvement was common (17 cases). Most patients with pulmonary blastomycosis (66%) presented with a chronic illness, and radiologic findings usually revealed local consolidation or a mass-like lesion. Nine patients developed ARDS with an associated mortality rate of 89%, compared with a 10% mortality for non-ARDS pulmonary cases. Antifungal treatment regimens varied widely, with amphotericin B often used for sicker patients. An epidemiologic evaluation revealed that the mean yearly incidence rate for blastomycosis quadrupled between 1980 and 1987 (0.31 cases/100,000 population) and 1988 to 1995 (1.23 cases/100,000 population) (p=0.00001). Most new blastomycosis cases in the 1988 to 1995 period occurred in three counties in the region where significant new construction projects have been underway. Conclusion: Blastomycosis is endemic in northeast Tennessee and the number of eases is increasing, coinciding with major new construction in the region. Clinicians in the area must be alert to this condition.
56

Endemicity and the Carrier Class: Modeling Foot-and-Mouth Disease in the Lake Chad Basin, Cameroon

Brostoff, Noah Alexander 26 June 2012 (has links)
No description available.
57

Was St. Paul's Bay Disease Endemic Syphilis?

Jebreen, Peter 09 1900 (has links)
There is a definite lack of information on treponemal infections in Canada. This thesis attempts to add to the knowledge on treponemal infections from studying outbreaks of the disease from smaller geographic regions of Canada. The purpose of this thesis is to study an alleged outbreak of syphilis, known as St. Paul's Bay Disease (SPBD) and to learn as much as possible about this disease, including its clinical and epidemiological characteristics, diagnosis and origins. This thesis provides evidence to support the contention that this 18th century outbreak of SPBD was not venereal syphilis, but rather endemic syphilis. The findings of this study were drawn from multiple lines of qualitative and quantitative evidence. The descriptions of SPBD by the medical practitioners of that time period reflect a high degree of similarity between SPBD and endemic syphilis. These descriptions contain information on the symptoms, method of treatment, method of transmission and diagnosis of SPBD. Furthermore, when SPBD was compared to the Sibbens of Scotland (a confirmed outbreak of endemic syphilis) they were found to be almost indistinguishable. Lastly, the distribution and prevalence of SPBD among the affected populations were found to be more characteristic of endemic syphilis. It is suggested that future research be carried out in three major areas: the ethnohistory of the various towns in Lower Canada, the origins of SPBD, and lastly, why the disease 'suddenly' disappeared. All of which will bring us one step closer to both understanding this outbreak and the history of treponemal infections in general. / Thesis / Master of Arts (MA)
58

Effects of wildfire burn severity on soil microbial communities and invasive plant species in the Cascade Range of Oregon /

Hebel, Cassie Lenae. January 1900 (has links)
Thesis (M.S.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 33-43). Also available on the World Wide Web.
59

Biogeography and conservation of Amazon palms

Valles, Carlos Mariano Alvez 22 February 2018 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2018-03-27T19:45:32Z No. of bitstreams: 1 carlosmarianoalvesvalles.pdf: 5972976 bytes, checksum: 908806a8077c5751983d6b9690d566cd (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-04-09T19:22:27Z (GMT) No. of bitstreams: 1 carlosmarianoalvesvalles.pdf: 5972976 bytes, checksum: 908806a8077c5751983d6b9690d566cd (MD5) / Made available in DSpace on 2018-04-09T19:22:27Z (GMT). No. of bitstreams: 1 carlosmarianoalvesvalles.pdf: 5972976 bytes, checksum: 908806a8077c5751983d6b9690d566cd (MD5) Previous issue date: 2018-02-22 / - / Palms are abundant in tropical forests and are recognized as effective bioindicators of hot climates. Moreover, play an important ecological and economic role for local populations. Though palms remain relatively well-conserved, they are under increasing pressure from deforestation. Therefore, endemicity is important for the delimitation of conservation areas. The purposes of the study is 1) to synthesize available information in the literature on species diversity, ecological aspects, use and conservation of Amazon palms (Chapter 1); to analyse palms species richness patterns relative to the latitudinal gradient, sample efforts, and deforestation in the Amazon region (Chapter 2); to compare richness and floristic similarities patterns among the Amazonian sub-regions (Chapter 2); to detect endemic areas for palms in the Amazon region (Chapter 3); and to determine whether the species that define these endemic areas are protected within conservation units (Chapter 3). Records of occurrences were extracted from the Global Biodiversity Information Facility (GBIF). The final dataset consisted of 17,310 records, for 177 species of Amazonian palms. The areas with the greatest richness were in the western, central and northeastern Amazon, principally at latitudes 0–5ºS. Most palms species grow in different habitats, but the highest species richness are found in terra firme forest. Palms are widely used with different category of use according to the regions and species, principally are used for human consumption, elaboration of utensils and tools, and construction of houses. Highest rates of deforestation (>2000 km2) were found in the southern and eastern brazilian Amazon, which coincide with low species richness and gaps in records. Similarity analysis resulted in two groups of sub-regions: the first included the Amazon s.s., Andes and Guiana, and the other group included the Plateau and Gurupi sub-region. The combination of PAE and NDM-VNDM analyses resulted in eight endemic palm areas in western Amazon shared with Andean sub-region. Of the species that define the endemic areas, five are threatened with extinction in one of three IUCN categories (EN, VU, NT), and they are not protected in any conservation units. In conclusion, the western Amazon, besides having high palm richness, also has palm endemic areas, especially, near the Andean sub-region and the Peruvian Amazon, and areas with low species richness, especially those areas with data deficiency, need to be further researched for a better knowledge of their diversity and richness patterns.
60

Immune modulatory effect of Dichrostachys cinerea, Carpobrotus dimidiatus, Capparis tomentosa and Leonotis leonurus

Hurinanthan, Vashka January 2009 (has links)
Submitted in fulfillment of the requirements for the Degree of Master of Technology: Biotechnology, Durban University of Technology, 2009. / Dichrostachys cinerea, Carpobrotus dimidiatus, Capparis tomentosa and Leonotis leonurus are all plants that are indigenous to South Africa. These plants are used in traditional medicine to treat various ailments. However, there is little or no scientific data to justify these traditional uses. Furthermore, it is difficult to reconcile traditional knowledge with scientific evidence because of the overwhelming targeting of signal-responsive systems by plant defensive compounds, multiple sites of action and the connectedness of the signaling pathways, which provide many cures and have pleiotropic effects. In order to evaluate the action spectrum of these plants, and validate its widespread use, this research evaluated the antibacterial, antioxidant, anti-inflammatory, anti-mosquito and immunomodulatory properties of these plants. Antimicrobial activity of the extract was determined by evaluating the bactericidal and fungicidal action using the agar disc diffusion assay. Anti-oxidative properties of the extracts were tested using the DPPH photometric assay. Anti-inflammatory properties were carried out using the 5-lipoxygenase assay. The larvicidal, repellency and insecticidal assay was determined against A.arabiensis. The safe use of these plant extracts was determined by evaluating toxicity, a brine shrimp lethality assay and an in vitro cell culture system using human myelogenous leukemia cell line. Potential carcinogenic activity was evaluated using the Ames Salmonella Mutagenecity assay. The immunomodulatory activity of the extracts on human peripheral blood mononuclear cells 6 was evaluated on freshly harvested lymphocytes using the MTT assay. Cytokine response was evaluated by measuring the secretion of interferon-gamma and interleukin-10. Elucidation of the B cells, T cells, activated T cells, CD 4+, CD 8+ and NK cells was performed by flow cytometry. The extracts showed anti-microbial activity against Escherichia coli, Pseudomonas aeruginosa, Klebsiella oxytoca, Salmonella typhimurium, Serratia marcescens, Bacillus cereus and Tricoderm sp. The highest activity was shown by methanolic and aqueous extracts of L. leonurus leaves followed by methanolic and aqueous extracts of D. cinerea. Extracts of C. tomentosa and D.cinerea demonstrated a higher degree of free radical scavenging than rutin, which was used as a standard indicating that these plants have strong antioxidant properties. None of the plants showed significant anti-inflammatory activity when compared to NDGA. In the anti-mosquito assays, the extracts showed strong repellency and insecticidal activity. L. leonurus extracts demonstrated the highest insecticidal and repellency activity against the mosquito, and was also found to cause ‗knockdown‘ and mortality. The extracts display no toxicity, cytotoxicity and mutagenicity. The immunological studies for immune modulation showed that the methanol extracts of these plants induce a Th1- predominant immune response because they significantly suppressed the secretion of IL-10 and augment IFN-γ production, which are hallmarks used to indicate a stimulation of the innate immune response. This study also provides new information, with respect to the potential use of these plants in producing a mosquito repellent and an immunostimulant. / National Research Foundation

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