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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.
11

Developmental processes in filarial worms

Delves, C. J. January 1986 (has links)
No description available.
12

Experimental ecology of epialgal bryozoans

Whitehead, John William January 1998 (has links)
No description available.
13

Efeito da composição polínica e qualidade proteica do alimento larval na determinação de castas em Melipona scutellaris (Hymenoptera: Apidae: Meliponini) / Effect of pollen composition and protein quality of larval food in caste determination in Melipona scutellaris (Hymenoptera: Apidae: Meliponini)

Mecca, Gláucya de Figueiredo 08 July 2015 (has links)
Melipona scutellaris (Apidae: Meliponini) é uma espécie de abelha sem ferrão popularmente conhecida como abelha Uruçu. Como outros meliponíneos, forma colônias perenes e apresenta diferenciação de castas. É encontrada na zona litorânea do Sul da Bahia ao Ceará, e em regiões do interior da Bahia e Pernambuco. Os ninhos são construídos somente em troncos ocos de árvores e apresentam arquitetura elaborada. As células de cria são verticais, arranjadas em favos horizontais formando placas que se sobrepõe. Seus principais recursos alimentares são pólen e néctar. A quantidade de alimento estocada nos potes está relacionada com a manutenção e produção de operárias, rainhas virgens e machos. Por não apresentar células de cria diferenciadas para o desenvolvimento de rainhas e operárias, não é possível estabelecer seguramente os fatores responsáveis pela determinação das castas neste grupo de abelhas. Estudos indicam que mecanismos genéticos e tróficos, incluindo a qualidade do alimento larval, somados a fatores ambientais interferem na produção de rainhas. Este estudo avaliou a variação do teor proteico e composição polínica do alimento larval ao longo de um ano. Os resultados mostraram que o valor proteico do alimento larval variou de forma equivalente para todas as colônias em todos os meses, com elevação significativa no mês de julho. O valor proteico do alimento larval não apresentou correlação com o valor proteico dos tipos polínicos. O valor proteico dos tipos polínicos não apresentou relação significativa com sua ocorrência no alimento larval, o que indica hábitos generalistas para a coleta de recursos alimentares. Através de bioensaios, foi testada a interferência do volume e da suplementação proteica do alimento larval na determinação de rainhas, cujos resultados demonstraram uma ocorrência de rainhas significativamente maior nos tratamentos com suplementação proteica. Conclui-se que embora os tipos polínicos não influenciem diretamente o teor proteico do alimento larval, os resultados encontrados sugerem que a alteração do valor proteico do alimento larval depositado nas células seja um fator importante na determinação de castas nesta espécie / Melipona scutellaris (Apidae: Meliponini) is an indigenous stingless bee species. Like other Meliponine, colonies are perennial and have female caste differentiation. This species is found from the cost area of Bahia to Ceará states. The nests are built only in hollow trees and have an elaborate architecture. The brood cells are vertical, arranged in horizontal overlapping combs. Pollen and honey are the main food source. The quantity of food stored in the pots is associated with the maintenance and production of workers, queens and males. Since there are no differences between the cells that queens and workers are reared, the factors responsible for caste determination are still unknown. Studies suggest that both genetic and trophic mechanisms, including the larval food quality, combined with environmental factors, interfere in the production of queens. This study evaluated the variation protein content and the pollinic composition of larval food among colonies of M. scutellaris across a year. The results showed that the protein content of the larval food varied equivalently for all the colonies at all months, but presenting an elevation on the protein content in July. The protein content in the larval food had no correlation with the pollen types. The protein content of the pollen types showed no significant relation with the pollen types occurring in the larval food, indicating that the species M. scutellaris presents generalist habits for food gathering. The interference of volume and protein supplementation of larval food on queen rearing determination was tested via bioassays, which results showed a significantly higher occurrence of queens in the treatments with protein supplementation. We concluded that although the pollen types did not influence directly the protein content of the larval food, the results obtained suggest that the variation of protein content of the larval food deposited in the cells may be an important factor in caste determination in this species
14

Physical and Biological Characteristics of Billfish Spawning Habitat in the Straits of Florida

Richardson, David Earl 04 January 2008 (has links)
The objective of this dissertation was to examine sailfish (Istiophorus platypterus) and blue marlin (Makaira nigricans) spawning in the Straits of Florida, with a specific focus on 1) the physical and biological characteristics of the spawning environment, and 2) the role of the region within the broader spawning patterns of these two species. In order to accomplish these objectives, two years of monthly ichthyoplankton collections and physical measurements across the Straits of Florida were combined with a finer-scale Lagrangian study. Additionally, a molecular species-identification methodology was developed that was both high-throughput and suitable for use with a broad taxonomic range of species. An initial analysis considered the diversity, assemblages and associated habitat of the larvae of large and medium size pelagic species. In total 36 species and 14,295 individuals were collected during this study, with the highest diversity occurring during the summer, and in the western frontal region of the Florida Current. Sailfish were included in an assemblage with Auxis rochei, A. thazard and Euthynnus alleterattus, all species found in highest abundance during the summer along the western edge of the Straits of Florida. Blue marlin grouped most closely with Thunnus atlanticus, Ruvettus pretiosus and Lampris guttatus, all summer spawners, whose larvae tended to occur further offshore. The primary environmental factors associated with these assemblages were SST (highest summer-early fall), day-length (highest early summer), thermocline depth (shallowest on the Florida side) and fluorescence (highest on the Florida side). A Lagrangian sampling effort was then used to more specifically evaluate the role of frontal zones in sailfish spawning. The results of this sampling indicated that the highest levels of sailfish spawning occurred in a frontal zone associated with the formation of a submesoscale frontal eddy. This spawning resulted in the first-feeding larvae occupying an area rich in prey items. Given the small spatial-scale of the front, and the distribution of the eggs of adult prey items, the results of this work would suggest that sailfish are actively targeting features for spawning that are favorable to the growth and survival of their larvae. Finally the relative importance of the Straits of Florida as a spawning ground was evaluated by calculating the annual egg production of both sailfish and blue marlin within this region. In total it was estimated that 2.1% of western Atlantic sailfish spawning and 1.6% of Atlantic wide blue marlin spawning occurs in the SF. Pop-up satellite tags deployed on sailfish at the start of the spawning season revealed their short residency times in the SF, suggesting that a large (≈10%) transient portion of the sailfish population is responsible for the SF egg production. These results indicate that the SF is a migratory bottleneck for sailfish. In conclusion the results of this study indicate that a hierarchy of physical and biological processes influence the distribution of billfish spawning in space and time. The results provide insights into the movement patterns and life history strategies of these species, and ultimately may aid in the development of the spatially explicit ecosystem based management approaches that are currently being advocated.
15

Temporal and Spatial Distribution of Larval Fish Community in Kenting, South Taiwan, and the Application of DNA Barcode Technique on the Species Identification

Ko, Hui-Ling 28 July 2007 (has links)
¡@¡@The main objectives of this study is to: (1) understand the recruitment pattern and mechanisms of fish larvae in the kenting waters, such as seasonal variation, distance from shoreline, depth, and diurnal migration of the assemblages of larvae fish. The correlation of the tempo-spatial variations of larval fish communities with temperature, salinity, and chlorophyll were also investigated; (2) to apply DNA barcode technique to identify fish larvae to lower taxonomic categories so as to reveal the temporal or spatial variation of the community structure of fish larvae that was unclear if the identification could only up to higher level. Additionally, DNA barcoding can help us to compile the diagnostic keys for larval fish species identifications. ¡@¡@For fish larval communities studies, fish larvae were collected from four seasons and two different depths during 2001-2002, and every two hours in a day during 10-11 April 2004 by the standard ORI net in Kenting. 527 specimens belonging to 86 taxa and 51 families of fish larvae were collected during 2001-2002. Randomization tests show significant differences between fish larval abundance vs. depths, and the number of families vs. seasons. Canonical correspondence analysis (CCA) shows that temperature and salinity were the main environmental factors, and chlorophyll was the second. 158 specimens belonging to 44 taxa and 34 families of fish larvae were collected during 24 hour survey. The abundance and diversity of fish larvae increase after sunset, and reach to their climax in the midnight. ¡@¡@For COI species identification, 1,505 of the post-flexion stage fish larvae specimens belong to 44 taxa and 34 families were collected by the four-time surveys of light trap in Kenting coral reef area during 2005-2007. Fifteen types of damaselfish larvae and five types of butterflyfish larvae were identified based on their morphological characters. The COI were used to identify the morphological types of damselfishes and butterflyfishes to species level. Fifteen morphological types of damselfishes (Pomacentridae) can be identified to 11 species and three genera. Five morphological types of butterflyfishes (Chaetodontidae) can be assigned to four species and one genus. After COI identification to the lower taxonomic levels, the ordination analysis can clearly reveal the seasonal variation. The result shows that applying DNA barcode technique to identify fish larvae to lower taxonomic categories indeed can reveal temporal or spatial variation of the community structure of fish larvae.
16

A preliminary study to quantify the suitable substratum of marine sessile invertebrates.

Chou, Ya-Lan 08 August 2003 (has links)
Seasonal reproduction of marine sessile organisms may be an adaptation of seasonal variation in suitable substratum availability. This research is focused on how to quantfy the suitable substratum of marine sessile organisms. Then the potential seasonal change of suitable substrate availability can be assessed. We tested 1-1.5 meters scale is a population closed spatial scale. At this scale we try to find ¡§intensification phenomenon¡¨ using different-size panels. If intensification phenomenon dose exist at 1-1.5 meter scale, then the amount of the suitable substratum can be estimated. We also compared three different current environments at Tiaoshi area in Nan-wan-Bay, the 3rd Nuclear Power Plant Inlet and the Hobihu Yacht Wharf to find out if the intensification phenomenon exists at this different situations. Lastly, sand and reef area were compared. Since reef areas has more suitable natural substratum than sand areas. The intensification phenomenon at 1-meter scale was not found. The larval density in water column might be highly heterogeneous even in very small scale. On the other hand, we consistently found higher settlement density in sand areas than in reef areas. This phenomenon may well have been caused by the intensification phenomenon.
17

Characterisation of the nicotinic acetylcholine receptor from Manduca sexta

Eastham, Helen Margaret January 1996 (has links)
No description available.
18

Studies on the acceptability and digestibility of artificial diets by crustacea

Kurmaly, Karim January 1990 (has links)
This work investigates the factors controlling production and determines the biophysical properties of cross-linked protein coated microencapsulated diets, with a view to enhancing their acceptability and digestibility to omnivorous and carnivorous larvae. To estimate optimal feed larvae of Penaeus monodon on microencapsulated diets, facilitate live transportation and add to the biological knowledge of the species, the relationship between metabolic rate/temperature and energetics of the larval stages were investigated. Also described, are laboratory growth and survival trials with P. monodon larvae fed on cross-linked protein microencapsulated diets. Success with P. monodon larvae, led to investigations on acceptability, growth and energetics of juvenile P. monodon reared on an artificial diet. For comparison, a similar line of approach was adopted with the carnivorous larvae of Homarus gammarus. Studies on the physiological energetics of the larvae were followed by investigations on acceptability, growth and digestibility of artificial diets fed to H. gammarus larvae. The final discussion attempts to correlate the contrasting larval growth/survival results to the different energy strategies adopted by the larvae.
19

Efeito da composição polínica e qualidade proteica do alimento larval na determinação de castas em Melipona scutellaris (Hymenoptera: Apidae: Meliponini) / Effect of pollen composition and protein quality of larval food in caste determination in Melipona scutellaris (Hymenoptera: Apidae: Meliponini)

Gláucya de Figueiredo Mecca 08 July 2015 (has links)
Melipona scutellaris (Apidae: Meliponini) é uma espécie de abelha sem ferrão popularmente conhecida como abelha Uruçu. Como outros meliponíneos, forma colônias perenes e apresenta diferenciação de castas. É encontrada na zona litorânea do Sul da Bahia ao Ceará, e em regiões do interior da Bahia e Pernambuco. Os ninhos são construídos somente em troncos ocos de árvores e apresentam arquitetura elaborada. As células de cria são verticais, arranjadas em favos horizontais formando placas que se sobrepõe. Seus principais recursos alimentares são pólen e néctar. A quantidade de alimento estocada nos potes está relacionada com a manutenção e produção de operárias, rainhas virgens e machos. Por não apresentar células de cria diferenciadas para o desenvolvimento de rainhas e operárias, não é possível estabelecer seguramente os fatores responsáveis pela determinação das castas neste grupo de abelhas. Estudos indicam que mecanismos genéticos e tróficos, incluindo a qualidade do alimento larval, somados a fatores ambientais interferem na produção de rainhas. Este estudo avaliou a variação do teor proteico e composição polínica do alimento larval ao longo de um ano. Os resultados mostraram que o valor proteico do alimento larval variou de forma equivalente para todas as colônias em todos os meses, com elevação significativa no mês de julho. O valor proteico do alimento larval não apresentou correlação com o valor proteico dos tipos polínicos. O valor proteico dos tipos polínicos não apresentou relação significativa com sua ocorrência no alimento larval, o que indica hábitos generalistas para a coleta de recursos alimentares. Através de bioensaios, foi testada a interferência do volume e da suplementação proteica do alimento larval na determinação de rainhas, cujos resultados demonstraram uma ocorrência de rainhas significativamente maior nos tratamentos com suplementação proteica. Conclui-se que embora os tipos polínicos não influenciem diretamente o teor proteico do alimento larval, os resultados encontrados sugerem que a alteração do valor proteico do alimento larval depositado nas células seja um fator importante na determinação de castas nesta espécie / Melipona scutellaris (Apidae: Meliponini) is an indigenous stingless bee species. Like other Meliponine, colonies are perennial and have female caste differentiation. This species is found from the cost area of Bahia to Ceará states. The nests are built only in hollow trees and have an elaborate architecture. The brood cells are vertical, arranged in horizontal overlapping combs. Pollen and honey are the main food source. The quantity of food stored in the pots is associated with the maintenance and production of workers, queens and males. Since there are no differences between the cells that queens and workers are reared, the factors responsible for caste determination are still unknown. Studies suggest that both genetic and trophic mechanisms, including the larval food quality, combined with environmental factors, interfere in the production of queens. This study evaluated the variation protein content and the pollinic composition of larval food among colonies of M. scutellaris across a year. The results showed that the protein content of the larval food varied equivalently for all the colonies at all months, but presenting an elevation on the protein content in July. The protein content in the larval food had no correlation with the pollen types. The protein content of the pollen types showed no significant relation with the pollen types occurring in the larval food, indicating that the species M. scutellaris presents generalist habits for food gathering. The interference of volume and protein supplementation of larval food on queen rearing determination was tested via bioassays, which results showed a significantly higher occurrence of queens in the treatments with protein supplementation. We concluded that although the pollen types did not influence directly the protein content of the larval food, the results obtained suggest that the variation of protein content of the larval food deposited in the cells may be an important factor in caste determination in this species
20

Using fish culture ponds to examine factors affecting larval hybrid striped bass growth and survival

Brumbaugh, Erica Nicole 24 August 2010 (has links)
No description available.

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