986 resultados para Assisted reproductive Technologies
Resumo:
Los caracteres de historia de vida son sensibles a la variación histórica o actual de los factores ambientales. Estudiar dicha variabilidad mediante la realización de estudios comparativos permite obtener evidencias sobre las causas de la evolución de ciertos caracteres. Los lagartos son excelentes modelos para el estudio de selección sexual y evolución del comportamiento social y reproductivo debido a que su relativa baja dispersión podría tener consecuencias evolutivas profundas en el desarrollo de distintas estrategias, ya que las poblaciones, al encontrarse más aisladas, podrían verse influenciadas por las fuerzas selectivas locales, mostrando una alta heterogeneidad espacial y temporal. Por eso nos propusimos realizar este trabajo para evaluar si existen diferentes estrategias reproductivas en los lagartos del género Tupinambis en distintos contextos ecológicos de la provincia de Córdoba. Para ello analizaremos distintas características de la historia de vida en poblaciones de estas especies tales como estructura de tamaño, sexo operativo, frecuencia reproductiva, tamaño de camada, condición corporal reproductiva, tamaño de madurez sexual, características espermáticas, elección de sitios de nidificación, etc. Además analizaremos la estructura genética de las poblaciones para inferir procesos demográficos históricos y patrones actuales de flujo génico y conectividad. The life history traits are sensitive to historical or current variation of environmental factors. Studying this variability by performing comparative studies allows obtaining evidence on the causes of the evolution of certain characters. Lizards are excellent models for studying sexual selection and evolution of social and reproductive behavior because their relatively low dispersal capabilities could have profound evolutionary consequences in the development of different strategies, since isolated populations may be stronger influenced by local selective forces, showing a high spatial and temporal heterogeneity. We decided to perform this study to assess whether there are different reproductive strategies in lizards of the genus Tupinambis in different ecological contexts of the Cordoba province. We will analyze different life history traits in populations of these species such as size structure, operational sex ratio, reproductive frequency, litter size, body condition, size at sexual maturity, sperm characteristics, choice of nesting sites, etc.. We also analyzed the genetic structure of populations to infer historical demographic processes and current patterns of gene flow and connectivity.
Resumo:
2
Resumo:
A composting Heat Extraction Unit (HEU) was designed to utilise waste heat from decaying organic matter for a variety of heating application The aim was to construct an insulated small scale, sealed, organic matter filled container. In this vessel a process fluid within embedded pipes would absorb thermal energy from the hot compost and transport it to an external heat exchanger. Experiments were conducted on the constituent parts and the final design comprised of a 2046 litre container insulated with polyurethane foam and kingspan with two arrays of qualpex piping embedded in the compost to extract heat. The thermal energy was used in horticultural trials by heating polytunnels using a radiator system during a winter/spring period. The compost derived energy was compared with conventional and renewable energy in the form of an electric fan heater and solar panel. The compost derived energy was able to raise polytunnel temperatures to 2-3°C above the control, with the solar panel contributing no thermal energy during the winter trial and the electric heater the most efficient maintaining temperature at its preset temperature of 10°C. Plants that were cultivated as performance indicators showed no significant difference in growth rates between the heat sources. A follow on experiment conducted using special growing mats for distributing compost thermal energy directly under the plants (Radish, Cabbage, Spinach and Lettuce) displayed more successful growth patterns than those in the control. The compost HEU was also used for more traditional space heating and hot water heating applications. A test space was successfully heated over two trials with varying insulation levels. Maximum internal temperature increases of 7°C and 13°C were recorded for building U-values of 1.6 and 0.53 W/m2K respectively using the HEU. The HEU successfully heated a 60 litre hot water cylinder for 32 days with maximum water temperature increases of 36.5°C recorded. Total energy recovered from the 435 Kg of compost within the HEU during the polytunnel growth trial was 76 kWh which is 3 kWh/day for the 25 days when the HEU was activated. With a mean coefficient of performance level of 6.8 calculated for the HEU the technology is energy efficient. Therefore the compost HEU developed here could be a useful renewable energy technology particularly for small scale rural dwellers and growers with access to significant quantities of organic matter
Resumo:
Age, growth and reproductive biology were investigated for whiting (Merlangius merlangus) captured from the Celtic Sea (ICES division Vllg), for the period January 2001 to January 2002. Females dominated the sex ratio of 1: 2.25. The relative abundance of females exceeded the number of males in all length classes. The relationship between weight (g) and total length (cm) was the same for male and female whiting. A total of 973 fish were aged and the maximum age recorded was 11 years. Results from an intercalibration exercise showed 87% agreement in age readings between the author and an expert in ageing whiting at the Marine Institute. Females were dominated by 2 year olds, while males were dominated by 3 year olds. Lx was estimated as 38cm and a growth rate was calculated K = 0.3769 year'1. Females were fully recruited to the fishery at 3 years of age, while the age at full recruitment (tr) for males was 4 years. Female whiting spawned from late February to June 2001 and matured at a total length of 23 cm in their first year. Female whiting reached L5o at a total length of 28 cm and 2.7 years of age. Male whiting spawned from February to June 2001. They matured at a total length of 21 cm and in their first year. Male whiting reached L50 at a total length of 30.4 cm and 3.6 years of age. The following critical points should be taken into account in the management of the Celtic Sea whiting stock: An Fpa should be established in order to assess the current level of fishing mortality; The maturity ogives need further study; The extent of gutting of large fish before landing by fishers in the fleet should be investigated and the apparent decline in size of 4 - 7 year old fish in the Celtic Sea between 1996 and 2001 needs to be assessed.
Resumo:
The research conducted for this thesis has been carried out over a two year period as part of the Mobile Tools and Technology for customer care (MOTTO) project. The project was funded under the Applied Grant scheme administered by Enterprise Ireland and Nortel Networks Ltd. It was a partnership project between Galway-Mayo Institute of Technology, University of Limerick, National University of Ireland Galway, and a global Internet and communications company, Nortel Networks. The project aimed to investigate the enabling mobile communications technologies in e-Business and mobile communications in the area of Business-to-Business (B2B) customer care. The development of the application discussed in this thesis was developed in conjunction with the Galway-Mayo Institute of Technology, University of Limerick and AMT Ireland. The decision to develop the application in the Electronics Company of AMT in Limerick came about as a result of the contact established by Mark Southern from the University of Limerick. Mark was involved in overseeing the development and assisted in establishing the user requirements.
Resumo:
The current study presents data on age and growth for plaice (Pleuronectes platessa L.) sampled between November 2003 and February 2005 in ICES areas Via (northwest coast of Ireland), Vila (Irish Sea), Vllg (Celtic Sea), VDj (southwest coast of Ireland) and VHb (west coast of Ireland), and data on the reproductive biology and maturity of plaice in ICES area Vllb (west coast of Ireland). This is the first detailed account of the biology of plaice for some of these areas. It is intended that this study will improve understanding of the life cycle of plaice and help fisheries scientists to better predict the effect of fishing effort on Irish plaice stocks. The overall length range found for plaice was 9-51.99cm TL, with a length range of 9-5 lcm TL for females and 9-40cm for males. In all ICES areas the length range for female fish was larger than for male fish. The age range of plaice sampled during this study was 1 to 16 years. In all ICES areas females had a greater range in ages and fish in the larger age groups. From analysis of length and age data it was concluded that there was a significant difference (P=0.000) in growth rate of males and females between ICES areas sampled in March 2004. The highest rate of fishing mortality was determined for ICES area Via (F=1.06) and the lowest for ICES area Vila (F=0.56). In each ICES area male and female plaice have fully recruited to the population by age 4, with the exception of females in ICES area Via, for which a tr value of 5 years was determined. Length at first maturity (L50%) was determined to be 23cm and 21cm for males and females respectively. Age at first maturity (A50%) was determined to be 3 years for both males and females. It was found that males and females in ICES areas Vllb, Vila and Via are well above the length and age at first maturity when they are recruited to the fishery. In ICES area Vllb female plaice spawn from November to March, with peak spawning occurring in February, and male plaice spawn from November to April, with peak spawning occurring in November. Spawning females had an age range of 2 to 10 years and spawning males had an age range of 2 to 7 years. From the oocyte length frequency distributions, it was determined that the plaice is a determinate batch spawner. During this investigation a total of 177 ovaries and 127 testes were staged using both macroscopic and histological criteria. The overall percentage of maturity stages which compared favorably between the two assessment methods was 22.03% for female plaice and 37.80% for male plaice. In general, the findings of this study indicate that there was a very poor match between the macroscopic and histological assessment methods. Given that the histological determination of these stages is based on the observation of a distinct set of developmental features, it is expected that it would be more accurate to use histologically assessed gonads to calculate the annual percentage maturity assessment. The biology of plaice in the areas studied is compared with previous studies of plaice in Irish and European waters.
Resumo:
5
Resumo:
1876
Resumo:
Magdeburg, Univ., Fak. für Informatik, Diss., 2014
Resumo:
Michael Friebe, editor ; Otto-von-Guericke-Universität Magdeburg, Institut für Medizintechnik, Lehrstuhl Kathetertechnologie und bildgesteuerte Therapie (INKA - Intelligente Katheter), Forschungscampus STIMULATE (Solution Centre for Image Guided Local Therapies)
Resumo:
Male-male and male-female interactions, reproductive habitat, and vocalizations of Hyla goiana B. Lutz, 1968 a member of H. polytaenia species group, are described. Three groups of calling males were surveyed along a small stream, at the Estação de Pesquisa e Desenvolvimento Ambiental de Galheiro, Perdizes municipality, State of Minas Gerais, Brazil. The mean distance between the nearest calling neighbors was 2.7 m, in accordance with an uniform distribution. Clutches (mean 180 eggs) were deposited in the stream, submerged and attached to plants. In two observed courtships the female moved towards a calling male that rapidly clasped her. In the male-male interaction, the males emitted advertisement and encounter calls and then engaged in physical combat. The males have a prepollical fang-like spine on each hand and several of them were observed with scratches on dorsum. The advertisement call consists of alternating harsh notes and a trilled of brief notes. The frequency of the call is lower than that of H. aff. polytaenia and H. cipoensis B. Lutz, 1968. The clutch characteristics of H. goiana are similar to those described for H. polytaenia Cope, 1870 and H. cipoensis.
Resumo:
The aim of this work was to gain knowledge about reproductive biology of the crab Armases rubripes (Rathbun, 1897) from an estuarine area of the Sepetiba Bay. Samples were taken monthly from February 2003 to January 2004 in the Sahy River estuary (22º56'S; 44º01'W), Rio de Janeiro, Brazil. The crabs were collected by hand during 15-minute catch-effort sessions conducted by two people. In the laboratory, the specimens were separated by sex, carapace width was measured and gonadal stage was checked macroscopically. A total of 830 individuals were caught - 304 males, 373 females (60 ovigerous females) and 153 juveniles. The ovigerous females were found almost year-round, except in November and April, showing a continuous reproductive period. They presented a size range from 8.2 to 15.0 mm carapace width (12.1 ± 1.7 mm). Color and macroscopical aspects determined five gonadal stages for males and females (immature, rudimentary, intermediary, developed and resting). First sexual maturity was estimated at 6.5 mm of carapace width for males and 8.1 mm for females. Individual fecundity varied from 200 to 11,460 eggs (4,458 ± 2,739 eggs). Mean egg size was 0.248 ± 0.026 mm, varying from 0.213 to 0.333 mm, while the volume ranged from 0.0051 to 0.0188 mm³ (0.0082 ± 0.0029 mm³).