93 research outputs found
Molecular analysis of phylogeographic subspecies in three Ponto-Caspian sturgeon species
Molecular cytogenetic differentiation of paralogs of Hox paralogs in duplicated and re-diploidized genome of the North American paddlefish (Polyodon spathula)
Chromosome evolution in fishes: a new challenging proposal from Neotropical species
We present a database containing cytogenetic data of Neotropical actinopterygian fishes from Venezuela obtained in a single
laboratory for the first time. The results of this study include 103 species belonging to 74 genera assigned to 45 families and 17
out of the 40 teleost orders. In the group of marine fishes, the modal diploid number was 2n=48 represented in 60% of the
studied species, while in the freshwater fish group the modal diploid complement was 2n=54, represented in 21.21 % of the
studied species. The average number of chromosomes and the mean FN were statistically higher in freshwater fish than in
marine fish. The degree of diversification and karyotype variation was also higher in freshwater fish in contrast to a more
conserved cytogenetic pattern in marine fish. In contrast to the assumption according to which 48 acrocentric chromosomes
was basal chromosome number in fish, data here presented show that there is an obvious trend towards the reduction of the
diploid number of chromosomes from values near 2n=60 with high number of biarmed chromosomes in more basal species to
2n=48 acrocentric elements in more derived Actinopterygi
Faune des eaux souterraines saumâtres de l\u27Asie Centrale
In the cave Kaptar-Khana (south-western Turkmenistan) was discovered a lake filled with water with a salinity of 11,68‰. This lake is inhabited by a fauna of marine origin - Foraminifera (three species), Molluscs (Pseudocaspia ljovuschkini sp.n.), Harpacticoida (genera Ectinosoma, Schizopera and Nitocra), Isopoda (Microcharon halophilus sp.n.) and possibly Nematoda (Oncholaimidae). The majority of the discovered species are related to species of circum-Mediterranean origin. Geological data do not permit to consider this fauna as a relict of any of the tertiary seas. The same applies to all other cases when animals of marine origin were discovered in subterranean waters of Central Asia (as for instance Microcharon kirghisicus Jank. on the shores of the lake Issyk-Kul). We can either admit a far greater anciennity of this fauna or an ability of its components to disperse very widely beyond the boundaries of marine transgressions
Faune des eaux souterraines saumâtres de l\u27Asie Centrale
In the cave Kaptar-Khana (south-western Turkmenistan) was discovered a lake filled with water with a salinity of 11,68‰. This lake is inhabited by a fauna of marine origin - Foraminifera (three species), Molluscs (Pseudocaspia ljovuschkini sp.n.), Harpacticoida (genera Ectinosoma, Schizopera and Nitocra), Isopoda (Microcharon halophilus sp.n.) and possibly Nematoda (Oncholaimidae). The majority of the discovered species are related to species of circum-Mediterranean origin. Geological data do not permit to consider this fauna as a relict of any of the tertiary seas. The same applies to all other cases when animals of marine origin were discovered in subterranean waters of Central Asia (as for instance Microcharon kirghisicus Jank. on the shores of the lake Issyk-Kul). We can either admit a far greater anciennity of this fauna or an ability of its components to disperse very widely beyond the boundaries of marine transgressions
Faune des eaux souterraines saumâtres de l\u27Asie Centrale
In the cave Kaptar-Khana (south-western Turkmenistan) was discovered a lake filled with water with a salinity of 11,68‰. This lake is inhabited by a fauna of marine origin - Foraminifera (three species), Molluscs (Pseudocaspia ljovuschkini sp.n.), Harpacticoida (genera Ectinosoma, Schizopera and Nitocra), Isopoda (Microcharon halophilus sp.n.) and possibly Nematoda (Oncholaimidae). The majority of the discovered species are related to species of circum-Mediterranean origin. Geological data do not permit to consider this fauna as a relict of any of the tertiary seas. The same applies to all other cases when animals of marine origin were discovered in subterranean waters of Central Asia (as for instance Microcharon kirghisicus Jank. on the shores of the lake Issyk-Kul). We can either admit a far greater anciennity of this fauna or an ability of its components to disperse very widely beyond the boundaries of marine transgressions
Adsorption of nitrogen tetroxide on silica gel /
Work performed at the Air Reduction Sales Company.Includes bibliographic references."August 31, 1949""AECU-438, (ARSC-30)"Mode of access: Internet
Identifying families with likely genetic protective factors against Alzheimer disease.
Elderly individuals who lived beyond the age of 90 years without dementia were hypothesized to have increased concentrations of genetic protective factors against Alzheimer disease (AD), conferring a reduced liability for this disease relative to less-aged nondemented elderly. However, testing this hypothesis is complicated by having to distinguish such a group from those who may lack genetic risk factors for AD, have had protective environmental exposures, or have escaped dementia for other reasons. Probands carrying genetic protective factors, however, should have relatives with lower illness rates not only for earlier-onset disease, when genetic risk factors are a strong contributing factor to the incidence of AD, but also for later-onset disease, when the role of these factors appears to be markedly diminished. AD dementia was assessed through family informants in 6,660 first-degree relatives of 1,049 nondemented probands aged 60-102 years. The probands were grouped by age (60-74, 75-89, and 90-102 years), and the cumulative survival from AD and 10-year-age-interval hazard rates of AD were calculated in their first-degree relatives. Cumulative survival from AD was significantly greater in the relatives of the oldest proband group (aged 90-102 years) than it was in the two younger groups. In addition, the reduction in the rate of illness for this group was relatively constant across the entire late life span. The results suggest that genetic factors conferring a lifelong reduced liability of AD may be more highly concentrated among nondemented probands aged >/=90 years and their relatives. Efforts to identify protective allele-bearing genes that are associated with very late-onset AD should target the families of nonagenarians and centenarians
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