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961.
Reproductive output, as the percentage of the mother weight devoted to egg production, was estimated for the burrowing shrimp
Callianassa tyrrhena in wet, dry and ash-free dry weight. Three biometrical approaches were used. First, the relationship between the egg mass
and the mother weight was determined. A second approach was to estimate the weight loss of the female caused by oviposition.
Similar results were obtained from these methods for dry and ash-free dry weight (about 20 and 35%, respectively), but not
for the wet weight estimation. The third approach, based on the weight loss of the ovary, did not reveal a constant value
for reproductive output throughout the female size range, although it was found that the ovary loses a constant percentage
of its weight during oviposition. This discrepancy is due to the fact that the ovary weight shows positive allometry to the
weight of the female body. The comparison of the three methods offers insight into the biological events that are related
to ovary maturation and oviposition. It is suggested that molting just before oviposition and its inhibition during the yolk
accumulation in the ovary play dominant roles in the expression of the reproductive output in the different approaches used.
Received: 17 July 1996 / Accepted: 11 September 1996 相似文献
962.
E. Marchina G. Piovani L. Vezzola D. Bellotti V. Cerri C. Groli Prof. S. Barlati 《黑龙江环境通报》2003,23(12):959-963
A 40-year-old woman underwent amniocentesis at 15.3 weeks of gestation. Chromosome analysis performed using QFQ, DA-DAPI and CBG banding revealed two de novo extra-chromosomal markers (ESACs) in 11 of the 16 colonies analysed. Fluorescence in situ hybridization (FISH) showed that both chromosomes came from the Yq11.22.1 region of the Y chromosome. PCR analysis of genes and STS localized on the Y chromosome excluded the Yp presence specifically of the SRY gene, and most of the euchromatic region of Yq. After extensive genetic counselling and considering both laboratory and second-level ultrasound data, the couple decided to continue the pregnancy. At 37.4 weeks of gestational age, a girl weighing 2750 g was born with an Apgar score of 9/10. A blood sample taken from the umbilical cord showed three cellular lines:mos47,XX, +mar1 ish.der (Y)(wcpY+) [21%]/48,XX, +mar1 ish.der (Y)(wcpY+), +mar2 ish.der (Y)(wcpY+) [41%]/46,XX [38%]. One year after birth, the baby was developing normally and had normal psychomotorial activity. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
963.
964.
Sérgio Morais Teresa M. Mata António A. Martins Gilberto A. Pinto Carlos A.V. Costa 《Journal of Cleaner Production》2010,18(13):1251-1259
This study uses the process simulator ASPEN Plus® and Life Cycle Assessment (LCA) to compare three process design alternatives for biodiesel production from waste vegetable oils that are: the conventional alkali-catalyzed process including a free fatty acids (FFAs) pre-treatment, the acid-catalyzed process, and the supercritical methanol process using propane as co-solvent. Results show that the supercritical methanol process using propane as co-solvent is the most environmentally favorable alternative. Its smaller steam consumption in comparison with the other process design alternatives leads to a lower contribution to the potential environmental impacts (PEI’s). The acid-catalyzed process generally shows the highest PEI’s, in particular due to the high energy requirements associated with methanol recovery operations. 相似文献
965.
C.M.V.B. Almeida A.J.M. Rodrigues S.H. Bonilla B.F. Giannetti 《Journal of Cleaner Production》2010,18(1):32-43
The life of a product begins with the initial product design concepts; the costs and potential impacts of a product are heavily influenced by the final design, the production processes, the economic and environmental costs of all raw materials. Additionally, both of these factors are very much affected by how the products are managed during and after consumer usage. Thus, there is an urgent need for a tool to facilitate the integration and assessment of environmental and economic demands into the product planning and development processes. The introduction of environmental accounting based on emergy as a tool to assist in product design is proposed. This complementary tool may be inserted into the conventional design methodology to facilitate in the selection of materials and processes as well as in the actual design of the products. To illustrate the application of the proposed method for material selection, PET (polyethylene terephthalate) bottles and aluminum cans for beverage packaging are compared. Despite the exceptional condition of aluminum recycling in Brazil, results show that the best option for beverage packages is the PET bottles. 相似文献
966.
Silvia H. Bonilla Rodrigo L. Guarnetti Cecilia M.V.B. Almeida Biagio F. Giannetti 《Journal of Cleaner Production》2010,18(1):83-91
Bamboo presents physical and mechanical characteristics, which turn it an alternative option for product development, replacing native or reforested wood. The sustainability assessment of a Dendrocalamus Giganteus species plantation in Brazil through the emergy methodology evidences a great weight of renewable (30% sej/sej) and human labour contributions (33% sej/sej). These contributions account for the great interface with environment and to the intensive work, respectively. The transformity value of bamboo production is 2.42E + 04 sej/J. The influence human labour has on the total emergy flow and on indicators is evaluated by taking into account different country locations (Brazil, Australia and China). Thus, a different transformity value for labour is assumed for each country. A ranking based on emergy sustainability index (ESI) values shows that bamboo production in China was the first placed, followed by Brazil and Australia (values of 1.18, 0.50 and 0.09, respectively). The insertion of indirect renewability embedded in labour results in the ranking modification, leading to plantation in Brazil in the first place, followed by the Australian and Chinese ones. The relative position of the bamboo systems is visualized in the ternary diagram expressed in terms of emergy. In an attempt to explore the relationship between sustainability and time, a graphic of ESI vs. global productivity is discussed in terms of a prospective evaluation. Indirect support areas of the bamboo production are calculated as a way to evaluate the sustainability-space relationship. 相似文献
967.
968.
969.
970.
A. V. Tyler 《Marine Biology》1973,19(3):258-261
Nineteen marine species were analyzed for caloric value; 7 of these were analysed for seasonal trends. Variation in caloric value for the polychaetesNephtys incisa andLumbrineris fragilis was not related to season.Pandalus montagui (decapod shrimp),Leptocheirus pinguis (gammarid amphipod),Astarte undata, Arctica islandica (pelecypods) had summer maxima.Meganyctiphanes norvegica (krill) had more complex seasonal changes involving winter and summer maxima. 相似文献