994 resultados para Reference sites
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n.s. no.82(1995)
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v.15:no.3(1919)
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We investigated the impact of fish cage culture on the zooplankton community structure in a tropical reservoir. We hypothesized that community abundance is greater near cages and increases over time due to the increase in food availability. Samplings were performed near, upstream and downstream from net cages, and before and after net cage installation. The abundance of zooplankton increased 15 days after the experiment was set up, followed by a reduction and finally increased. Rotifer abundance showed significant differences among sites (p<0.05) and sampling periods (p<0.001). Significant differences were also observed in total zooplankton and cladoceran abundance (p<0.001). The spatial and temporal variation of the physical and chemical variables were indirectly correlated with the structure and dynamic of the zooplankton community, as they indicated the primary production in the environment. Our hypothesis was rejected, since the zooplankton was abundant at the reference site. Only rotifers showed higher abundance near cages, due to the influence of food availability. Community dynamics during the experiment was also correlated to food availability. Our results suggest an impact of fish farming on the zooplankton community.
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v.25:pt.1(1939)
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v.25:pt.3(1946)
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v.25:pt.2(1939)
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v.25:pt.4(1959)
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ABSTRACT Mugil liza Valenciennes, 1836 is an economically important food fish and has been recommended for aquaculture in South America. A total of 278 fishes were collected in the spring and summer of 2009 and 2010. These fish were sorted into sample groups according to their size class. We used Bayesian statistics and 95% credible intervals for each parameter tested were calculated. Fish studied harbored a total of 15 different species of parasites. Diversity of parasite species found on Mugil liza was greatest at the S.R.C. collection site, but evidenced a lower species richness than at A.R. site. The 1st size fishes of both sites evidenced greater parasite diversity than either 2nd or 3rd size fish. Differences observed could be explained by the different use of habitat types at the two sites or differential susceptibility to infection by parasites. The dominance of D. fastigatainfluenced observed results of lower community diversity indexes. New works elucidating different parasite life cycles within juvenile and adults ofM. liza in Argentina, promise to be important for determining the risk of the parasitism by zoonotic metacercariae A. (P.) longa and use of this fish as food and an economic resource, and the possible use of mullet parasites in other promising fields as indicators of biodiversity, and/ or water contamination.
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The aim of this paper is to analyse the effects of recent regulatory reforms that Spanish Health Authorities have implemented in the pharmaceutical market: the introduction of a reference price system together with the promotion of generic drugs. The main objectives of these two reforms are to increase price competition and, ultimately, reduce pharmaceutical costs. Before the introduction of reference prices, consumers had to pay a fixed copayment of the price of whatever drug purchased. With the introduction of such system, the situation differs in the following way: if (s)he buys the more expensive branded drug, then (s)he pays a sum of two elements: the copayment associated to the reference price plus the difference between the price of this good and the reference price. However, if the consumer decides to buy the generic alternative, with price lower than the reference price, then (s)he has to pay the same copayment as before. We show that the introduction of a reference price system together with the promotion of generic drugs increase price competition and lower pharmaceutical costs only if the reference price is set in a certain interval. Also profits for the duopolists might be reduced. These results are due to the opposing effects that reference prices have on branded and generic producers respectively.
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Estudi elaborat a partir d’una estada a l’Institut of Archaeology de la University College of London i a jaciments arqueològics espanyols. L’objectiu ha estat l’aprenentatge del mètode carpològic a través de l’anàlisi de fruit i llavors recuperades a jaciments de cronologies paleolítiques i l’estudi de les col·leccions de referència de Institute of Archaeology. Els jaciments analitzats han estat el Molí del Salt (Vimbodí, Tarragona) i Atapuerca (Burgos). L’estudi de mostres carpològiques de jaciments Neolítics d’una regió del Nord de Xina han permès l’apropament previ a restes de cronologies més recents dels primers agricultors i ramaders.
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Shrews of the genus Crocidura from Sicily revealed a new karyotype from Europe: 2n = 36, NF = 56, NFa = 52. With reference to the revision of Vesmanis (1976), this shrew is provisionally attributed to C. caudata Miller, 1901 and it is proposed to call it the "Sicilian shrew". Its chromosome complement is similar to that of shrews from Canary Islands and a species from Burundi (Central Africa), suggesting that it might have split off from a line of Paleotropical origin. Following these findings, the modern concept of Mediterranean island colonization by shrews must be revised. The distinctive characteristics of Mediterranean shrews should also be revised.
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OBJECTIVES: In this population-based study, reference values were generated for renal length, and the heritability and factors associated with kidney length were assessed. METHODS: Anthropometric parameters and renal ultrasound measurements were assessed in randomly selected nuclear families of European ancestry (Switzerland). The adjusted narrow sense heritability of kidney size parameters was estimated by maximum likelihood assuming multivariate normality after power transformation. Gender-specific reference centiles were generated for renal length according to body height in the subset of non-diabetic non-obese participants with normal renal function. RESULTS: We included 374 men and 419 women (mean ± SD, age 47 ± 18 and 48 ± 17 years, BMI 26.2 ± 4 and 24.5 ± 5 kg/m(2), respectively) from 205 families. Renal length was 11.4 ± 0.8 cm in men and 10.7 ± 0.8 cm in women; there was no difference between right and left renal length. Body height, weight and estimated glomerular filtration rate (eGFR) were positively associated with renal length, kidney function negatively, age quadratically, whereas gender and hypertension were not. The adjusted heritability estimates of renal length and volume were 47.3 ± 8.5 % and 45.5 ± 8.8 %, respectively (P < 0.001). CONCLUSION: The significant heritability of renal length and volume highlights the familial aggregation of this trait, independently of age and body size. Population-based references for renal length provide a useful guide for clinicians. KEY POINTS: • Renal length and volume are heritable traits, independent of age and size. • Based on a European population, gender-specific reference values/percentiles are provided for renal length. • Renal length correlates positively with body length and weight. • There was no difference between right and left renal lengths in this study. • This negates general teaching that the left kidney is larger and longer.