944 resultados para 1949-


Relevância:

20.00% 20.00%

Publicador:

Resumo:

16 cartas + 1 tarjeta postal (manuscritas y mecanografiadas) ; entre 210x300mm y 150x105mm

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Two fishermen pulling a net in a boat in Lune Estuary, North West England, UK. This photo is part of a Photo Album that includes pictures from 1935 to 1954.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Houses close to River Lune at Lancaster, North West England, UK. This photo shows the polluted River Lune in July 1949. This photo is part of a Photo Album that includes pictures from 1935 to 1954.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Cockersand Abbey Lighthouse, in River Lune the Baulk, River Lune estuary on the Lancashire Fylde peninsula in the North West of England, UK. This photo is part of a Photo Album that includes pictures from 1935 to 1954.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Photo of a check trap in Abbeystead Fish Pass in the River Wyre in 1949. The River Wyre is located in the North West of England, UK. This photo is part of a Photo Album that includes pictures from 1935 to 1954.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

River Clough Farfield Weir showing a gap made for migratory fish in June 1949 (Lune). This photo is part of a Photo Album that includes pictures from 1935 to 1954. This Album was held by the EA North West.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

ChurchTown Weir in the River Wyre, North West of England, UK. This photo is part of a Photo Album that includes pictures from 1935 to 1954.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

As California entered its sixth consecutive year of drought, the onset of a positive sea surface temperature anomaly in the equatorial Pacific and other indicators of a developing ENSO event were observed. This brought the following question from the media, water officials, and the public: What effect will El Niño have on the current rainfall season in general and on the intraseasonal distribution of rain in particular? To answer the question, the historical San Francisco rainfall record was examined in relationship to previous ENSO events.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Length frequency distributions of the sea bream collected during the period 1953 to 1958 have been analysed. The increase in average sizes of the sea bream with depth suggests a movement to deeper waters with increase in size. By numbers, the sea bream is more abundant between 21 and 30 fathoms than in deeper areas. The recruitment was continuous and regular. There is no sign of entry or progression of a dominant brood throughout the period under study. Length frequency distribution shows three distinct modes. The first mode occurs regularly but does not progress beyond 40cm, recruitment being balanced by natural and fishing mortality. The other two which are not regular are probably the result of fishing outside regular areas. Short sections of “growth” lines which fit into one another when extrapolated, are evident. The larger lines obtained by extrapolation are parallel to one another. These tentative "growth lines" indicate that this species which enters the fishing grounds, when 15 cm or larger in length are exploited by the trawl fishery for a period of three to four years. This species appears to be six months old when it enters the fishing grounds and increases in length by about 37.5 cm in the next 30 months. Later growth slows down. The average size of the specimens sampled continued to get smaller from 1953 till 1957. It is shown that this reduction in size is due to increased fishing effort.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The present work is now concentrated mainly on the Tilapia fishery. As a result of past experience it is easier to direct efforts in a way likely to give useful results. Work on the Tilapia is now beyond the purely exploratory stage and these fishing experiments are being carried but in areas which are known to contain large numbers of Tilapia. Nets of different mesh size are being used in order to catch all stages of these fish. These nets are being fished at the surface and at the bottom, close to the shore and further out. The data collected should provide more precise information regarding the periodic migration, both vertical and horizontal, of these fish, a better understanding of their life history and breeding habits, and indicate' the potential possibilities of this fishery. These data should explain the variation in numbers of fish caught by Africans during different months of the year; they should also make it possible to determine more exactly the best type of net for use in this particular fishery.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The phylogenetic relationships within the genus Takifugu Abe, 1949 (Tetraodontiformes, Tetraodontidae) remain unresolved. Because of the use of Takifugu as model organisms, the resolution of these relationships is crucial for the interpretation of evolutionary trends in biology. Pufferfishes of this genus are comprised of a comparatively small number of species and are mainly distributed along the coastal region of the western part of the Sea of Japan and the coastline of China. Mitochondrial gene sequences were employed to test the phylogenetic hypotheses within the genus. Seventeen species of the genus were examined. Molecular phylogenetic trees were constructed using the maximum parsimony, neighbor-joining, maximum likelihood and Bayesian methods. Our hypothesis of internal relationships within the genus differs from previous hypotheses. Our results indicate that (1) the genus Takifugu is a monophyletic assemblage; (2) the genus is divided into 6 subgroups based on the molecular data; and (3) there is low genetic diversity among the species within this genus. In addition, speciation within Takifugu appears to be driven by hybridization and isolation by distribution. Our results also suggested that the taxonomy in the genus should be clarified based on both molecular and morphological data.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The phylogenetic relationship of 5 genera, i.e. Diplozoon Nordmann, 1832, Paradiplozoon Achmerov, 1974, Inustiatus Khotenovsky, 1978, Sindiplozoon Khotenovsky, 1981, and Eudiplozoon Khotenovsky, 1985 in the subfamily Diplozoinae Palombi, 1949 (Monogenea, Polyopisthocotylea) was inferred from rDNA ITS-2 region using neighbour-joining (NJ), maximum likelihood (ML) and Bayesian methods. The phylogenetic trees produced by using NJ, ML and Bayesian methods exhibit essentially the same topology. Surprisingly, freshwater species of Paradiplozoon from Europe clustered together with species of Diplozoon, but separated from Chinese Paradiplozoon species. The results of molecular phylogeny and lower level of divergence (4(.)1-15(.)7%) in ITS-2 rDNA among Paradiplozoon from Europe and Diplozoon and, on the other hand, high level of divergence (45(.)3-53(.)7%) among Paradiplozoon species from Europe and China might indicate the non-monophyletic origin of the genus Paradiplozoon. Also, the generic status of European Paradiplozoon needs to be revised. The species of Paradiplozoon in China is a basal group in Diplozoinae as revealed by NJ and Bayesian methods, and Sindiplozoon appears to be closely related to European Paradiplozoon and Diplozoon. with their relationship to Eudiplozoon and Inustiatus being unresolved.

Relevância:

20.00% 20.00%

Publicador: