• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1185
  • 201
  • 135
  • 111
  • 76
  • 72
  • 72
  • 72
  • 72
  • 72
  • 71
  • 38
  • 32
  • 28
  • 19
  • Tagged with
  • 2317
  • 202
  • 197
  • 146
  • 141
  • 140
  • 136
  • 124
  • 119
  • 119
  • 117
  • 113
  • 111
  • 109
  • 97
  • 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

Burials at Ialysos and Kameiros (Rhodes) in the mid archaic period, ca. 625-525 B.C.

Gates, Charles Warner. January 1979 (has links)
Thesis (Ph. D.)--University of Pennsylvania, 1979. / Photocopy of typescript original. Ann Arbor, Mich. : University Microfilms International, 1981. -- 21 cm. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 387-397) and index.
202

European Fire Ants on Mount Desert Island, Maine: Population Structure, Mechanisms of Competition and Community Impacts of Myrmica Rubra L. (Hymenoptera: Formicidae)

Garnas, Jeffrey January 2004 (has links) (PDF)
No description available.
203

Interactions between Homoptera and the European Red Ant, Myrmica rubra (L.) (Hymenoptera: Formicidae), on Mount Desert Island, Maine

McPhee, Katherine E. January 2008 (has links) (PDF)
No description available.
204

A history of the regular Baptists in Rhode Island, 1825-1931

Russell, Charles Allyn January 1959 (has links)
Thesis (Ph.D.)--Boston University / The story of Baptist beginnings in Rhode Island through Roger Williams and John Clarke is a familiar one. The writer of this dissertation, while reviewing the early and familiar chapter of Baptist beginnings in America, concentrates upon the more recent and neglected period from 1825 to 1931. The result of the research is the first state history of Rhode Island Baptists. The principal primary sources for this study have been the annual minutes of the Rhode Island Baptist State Convention; the yearbooks of the Warren, Providence, Narragansett, and Roger Williams associations; and the minutes of seven representative Baptist churches. State, city, and town histories have also been consulted as well as Rhode Island newspapers and contemporary Baptist magazines and journals. [TRUNCATED]
205

Adoptive applicants and children released for adoption

O'Hara, Edward Joseph January 1956 (has links)
Thesis (M.S.)--Boston University
206

A more comprehensive approach to school accountability: a case study of inspection reports in England, Rhode Island, and Massachusetts

Wilhite, Sarah January 2004 (has links)
Boston University. University Professors Program Senior theses. / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / 2031-01-02
207

The sediment sources of Atlantic shore beaches between Montauk Point and Democrat Point, Long Island, New York, USA

Morgan, Peter January 1990 (has links)
Speculation has arisen regarding the possibility of an additional offshore sediment source on the Atlantic inner shelf south of Long Island, New York, as a result of deficits in recent south shore budgetary estimates. In view of the importance of Long Island's inner shelf as a possible sediment source for other conflicting commercial uses in the future, the present study attempts to compare the known source at Montauk Point with sediments from buried palaeodrainage channels and nearby offshore and to examine the degree to which they may be linked to south shore beaches. Samples from each of these three environments were subjected to S.E.M. analysis using a checklist approach. Qualitative results comparing individual quartz grain surface feature variability with transport distance west of Montauk Point divided the south shore into three sections largely on the basis of mechanically derived and source textures: the distinctive glacial deposits formed in Ronkonkoma moraine at Montauk Point; Headlands section beaches, and Fire Island beaches. Surface feature variability plots and between sample variability plots revealed a more complex pattern of surface feature development than may be expected from what appears to be generally a single alongshore-trending wave dominated regime, which suggests an additional control such as an offshore source. Canonical variate analysis, as well as cluster and factor analyses confirmed qualitative findings and tentatively link offshore lobe deposits with onshore Fire island beaches, and distinguish them from Headlands beaches and Montauk Point. Strong supporting and complementary links between qualitative results, photographic evidence and subsequent statistical analysis suggest that the technique employed is a useful and valid sedimentological tool.
208

Reproductive biology of Pacific yew (Taxus brevifolia)

Anderson, Erika Dee 17 May 2018 (has links)
Taxus brevifolia Nutt., commonly known as Pacific or Western yew, is a conifer native to the Pacific Northwest of North America. Contrary to other Taxus species, T. brevifolia staminate strobili are usually located on two-year old foliage though they may occur on foliage from one to five years old. This delayed staminate strobilus development may be an adaptation to the low light environment where T. brevifolia grows. Microsporogenesis was found to occur in the fall preceding pollination. Isobilateral tetrads were visible as early as mid-October. Over-wintering staminate strobili usually contained separate microspores. In 1996 through 1999, pollination occurred in March and April in two natural forest sites on southern Vancouver Island, British Columbia. Low amounts of airborne pollen and a prolonged pollination period indicated low pollination success within T. brevifolia. Female receptivity was measured by the presence of a pollination drop and protandry up to 18 days was observed. In vitro pollen germination was moderate to good, ranging from 65% to 88%. DAPI fluorescence staining showed successful male gametophyte development in vitro. The phenology of megasporogenesis and free nuclear mitosis within the megagametophyte was variable and this development occurred anytime between early February until the end of June. One megaspore mother cell developed from the sporogenous tissue and underwent meiosis forming a linear tetrad of megaspores. Though up to three of the megaspores may be functional, the chalazal megaspore developed faster than the others and became the dominant megaspore. Cellularization of the megagametophyte began in mid-April and continues until early June. The presence of an ephemeral ventral canal nucleus was confirmed. Fertilization was observed in June in 1996. The mature egg cell cytoplasm and sperm structure was used to infer paternal inheritance of plastids and biparental inheritance of mitochondria. To examine this further, DNA was extracted from hybrid embryos of T. brevifolia and T. x media Rehd. Paternal contribution of mitochondria was confirmed using the probe rpS 14-cob. The T. x media parents produced two bands of 526 and 970 by in length, whereas the T. brevifolia parents produced only one band (526 bp). The chloroplast probes were not effective at amplifying Taxus DNA although appropriate sized bands were produced in Pinus contorta. Proembryos occurred from mid-May to mid-June. Sixteen nuclei were present before cellularization. Early embryos were present from mid-May to mid-August. Simple polyembryony was observed up to the massive embryo stage and differential growth of the embryonal cells was interpreted as incomplete cleavage polyembryony. Mid-embryos were present from mid-June to late August and had a distinct protoderm and focal zone. Late embryos were visible from mid-July onwards. Starch began accumulating at the early embryo stage, whereas, proteins and lipids accumulated in the late embryo stage. The presence of a red aril corresponded to increased amounts of lipid in the megagametophyte cells. Individual seeds matured from July until November. The seed efficiency ranged from 0% to 16% and averaged 5%. Pre-zygotic loss was the most common fate of ovules, followed by post-zygotic loss. Possible causes of this poor seed efficiency are poor pollination success, insect damage or light limitation. / Graduate
209

Comparison of actinobacterial diversity in Marion Island terrestrial habitats

Sanyika, Walter Tendai January 2008 (has links)
Philosophiae Doctor - PhD (Biotechnology) / The major aim of this study is to determine and compare the distribution of bacteria and actinobacteria in Marion Island terrestrial habitats. / South Africa
210

The distribution and abundance of macro-invertebrates in the major vegetation communities of Marion Island and the impact of alien species

Hanel, Christine 15 November 2010 (has links)
In this study macro-invertebrates were sampled quantitatively in 10 lowland vegetation communities on Marion Island over a one-year period commencing in May 1996 as part of a larger investigation into the distribution, abundance and species energy use of invertebrates across an altitudinal transect on Marion Island. The data collected for this particular study were used to investigate the habitat specificity and seasonality of the macro-invertebrates, as well as the impact of alien species on the local community. As part of the latter study a watching brief for alien species was kept throughout the field year and the alien species list was updated accordingly. The quantitative data were also used to compare changes in the density and biomass of selected macro-invertebrate species between 1976/77 and 1996/97 by reworking the data on macro-invertebrates collected by Alan Burger in 1976/77 during the course of his work on the Lesser Sheathbill. In the current study it was found that the majority of the macro-invertebrate species are not particularly habitat specific. Rather, they generally prefer either moist mire habitats, or the more well-drained non-mire vegetation complexes. In addition, many of the species had pronounced peaks in abundance in a given season (winter, summer, autumn and spring peaks were recorded), although this seasonality varied between species and between habitats for a given species. Although this finding does not support previous generalizations concerning an absence of seasonality in sub-Antarctic invertebrates, it does show that sub-Antarctic invertebrates, like their Antarctic counterparts, may have extremely flexible life history strategies. Limnophyes minimus was found to be one of the most abundant alien species on the island, and reached high densities in most of the plant communities sampled, with the highest density being recorded in the Cotula plumosa biotically influenced community (annual mean of 4365 individuals.m-2 ) and the lowest in the Crassula moschata salt spray community (annual mean of 41 individuals.m-2 ). Estimates of litter ingestion indicated that L. minimus larvae are capable of consuming between 0.07 and 8.54 g(dry mass)·m-2 per year, depending on the community. In some communities this litter consumption amounted to an order of magnitude more than that consumed by Pringleophaga marioni (Lepidoptera, Tineidae). Although the larvae of this moth species are thought to represent the bottleneck to nutrient recycling on the island, this study showed that midge larvae may also contribute substantially to this process. As a consequence, the considerable changes that have been predicted to occur in Marion Island's terrestrial ecosystem as a consequence of enhanced predation by mice on P. marioni larvae, may be retarded or obscured by the contribution of the midge larvae to nutrient cycling. Hence, it is suggested that greater attention be given to the small and inconspicuous elements of the alien sub-Antarctic faunas because such species may have profound consequences for ecosystem functioning on these islands. The likely impact of alien species on the terrestrial macro-invertebrates, and the communities they belong to, was further highlighted by the dramatic decline in the biomasses of the macro-invertebrates between 1976/77 and 1996/97. Significant declines in biomass of between 83-97% were found for Lepidoptera larvae (mostly Pringleophaga marioni) and for weevils, the major prey species of the introduced house mouse between 1976/77 and 1996/97, although non-prey species appear to have shown either no changes (the indigenous snail Notodicus hookeri) or increases in abundance (the introduced slug Deroceras caruanae). However, differences in sampling strategies adopted by these two studies and others investigating macro-invertebrate abundances mean that the current results may well be underestimates of change, while other studies must be interpreted with considerable caution. Nonetheless, the current findings and those of authors suggest that mice may be having pronounced impacts on the terrestrial ecosystem at Marion Island. In sum, the findings of this thesis indicate that considerably more attention must be given to well-planned collaborative work to address critically important management questions, identified by the Prince Edward Island Management Committee, and that considerable care must be taken to prevent the further introduction of alien species to sub-Antarctic islands. Copyright / Dissertation (MSc)--University of Pretoria, 2010. / Zoology and Entomology / unrestricted

Page generated in 0.0701 seconds