996 resultados para Central-america
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As cutias são animais que vivem nas Américas Central e do Sul, com potencial zootécnico e que despertam crescente interesse científico. O objetivo deste estudo foi estabelecer um padrão para colheita de sêmen por eletroejaculação em cutia-parda (Dasyprocta azarae). Foram utilizados machos adultos (n=4) anestesiados e submetidos a quatro séries de 20 estímulos eletroejaculatórios, com 3 segundos de duração cada, com uma intensidade de 2, 4, 6 e 8 volts, com dois minutos de intervalo entre cada série. A colheita de sêmen foi obtida em todos os animais, com ereção parcial com 2 volts, ereção evidente com 4 volts, ejaculação com 6 volts e exacerbação da glande e exteriorização das espículas penianas com 8 volts, observando-se espermatozoides em 100% das amostras. A técnica descrita para colheita de sêmen em cutia-parda foi eficaz.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The pattern of availability of free DNA phosphates, and the kind of DNA-protein complex arrangement, both induced by nuclear basic proteins, and the richness in arginine residues in these proteins were investigated cytochemically and cytophysically in spermatozoa of the South-American Hylidae species, Hyla fuscovaria and Hyla biobeba. The aim was to demonstrate differences at the level of sperm histones in two species of Hyla until recently considered to be congeneric. The results indicated differences in the spermatozoal nuclear basic proteins and DNA-protein complexes when the two species were compared. The spermatozoa of Hyla biobeba were assumed to be likely to contain a Bloch's ''type 3'' protein type (intermediate sperm basic protein), similarly to Hyla species of North and Central America. on the other hand, the data obtained for the spermatozoa of Hyla fuscovaria indicated that they contain a protamine or protamine-like protein, differing from Hyla biobeba and Hyla species of North and Central America. It is suggested that the differences reported here may be genus-specific, since Hyla fuscovaria has recently been reclassified as Scinax fuscovaria based on parameters other than sperm histone types. These findings are in agreement with the general view of a wide variability in sperm nuclear proteins in the Anura group.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Leaf-cutting ants of the genera Acromyrmex and Atta are considered the principal polyphagous pests of the Neotropics. Although some members of these genera are of economic importance, have a broad geographic distribution, and are extremely good colonizers, others are endemic and closely interact with native ecosystems. Control is generally practiced against any colony, irrespective of its taxonomic status. Indiscriminate control coupled with habitat destruction threatens endemic species with extinction, and, through habitat simplification, favors other pest species. As nests of Atta are large, having several square meters of nest surface, the endemic taxa can be easily used as environmental indicators for natural ecosystems. Likewise, the pest species can be used to detect environmental disturbance. As these ants are keystone species and easily identified by nonspecialists, efforts should be made to integrate these into viable conservation programs.
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Wild Arachis germplasm includes potential forage species, such as the rhizomatous Arachis glabrata and the stoloniferous A. pinto and A. repens. Commercial cultivars of A. pintoi have already been released in Australia and in several Latin American countries, and most of these cultivars were derived from a single accession of A. pintoi (GK 12787). Arachis repens is less productive as a forage plant than is A. pintoi. However, it can be crossed with A. pintoi, and thus has good potential as germplasm for the improvement of A. pintoi. Arachis repens is also used as an ornamental plant and ground cover. Many new accessions of these two stoloniferous species are now available, and they harbor significant genetic variability beyond that available in the few older accessions, previously available. Therefore, these new accessions need to be conserved, documented and considered in terms of their potential for crop improvement and direct commercial use. Sixty-four accessions of this new germplasm were analyzed using RAPD analysis. Most of the accessions of A. repens grouped together into a clearly distinct group. In general, the accessions from the distinct valleys of the Jequitinhonha, Sao Francisco and Parana rivers did not group together, suggesting there is not a tight relation between dispersion by rivers and the geographic distribution of genetic variation in these species.
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The subfamily Tetragonopterinae is composed by a large number of species distributed in South and Central America. This subfamily has many taxonomic and phylogenetic problems, being considered by several authors as an artificial group. With the objective to better understanding the relationships among the components of this fish group, cytogenetic studies were conduced on five species of Tetragonopterinae. Astyanax janeiroensis had 2n=50 chromosomes (6M+14SM+14ST+16A), Hyphessobrycon reticulatus had 2n=50 chromosomes (14M+20SM+16ST), Hollandichthys multifasciatus had 2n=50 chromosomes (10M+12SM+28ST), Ctenobrycon hauxwellianus had 2n=50 chromosomes (10M+6SM+34ST), and Phenacogaster cf. pectinatus had 2n=46 chromosomes (12M+2ST+32A). Only A. janeiroensis had multiple NORs, while all other species had simple NORs. Small heterochromatic blocks were observed in the chromosomes of all species in a pericentromeric position. A. janeiroensis also had some chromosomes with large heterochromatic blocks in a terminal position and a pair with an interstitial block. The karyotypic evolution of each genus is discussed.
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A network was established to acquire basic knowledge of Cryptococcus neoformans in IberoAmerican countries. To this effect, 340 clinical, veterinary, and environmental isolates from Argentina, Brazil, Chile, Colombia, Mexico, Peru, Venezuela, Guatemala, and Spain were typed by using M13 polymerase chain reaction-fingerprinting and orotidine monophosphate pyrophosphorylase (URA5) gene restriction fragment length polymorphsm analysis with Hhal and Sau961 in a double digest. Both techniques grouped all isolates into eight previously established molecular types. The majority of the isolates, 68.2% (n=232), were VNI (var. grubii, serotype A), which accords with the fact that this variety causes most human cryptococcal infections worldwide. A smaller proportion, 5.6% (n=19), were VNII (var. grubii, serotype A); 4.1% (n=14), VNIII (AD hybrid), with 9 isolates having a polymorphism in the URA5 gene; 1.8% (n=6), VNIV (var. neoformans, serotype D); 3.5% (n=12), VGI; 6.2% (n=21), VGII; 9.1% (n=31), VGIII, and 1.5% (n=5) VGIV, with all four VG types containing var. gattii serotypes B and C isolates.
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Background: Rapid demographic ageing will soon lead to large increases in the numbers of persons with dementia in developing countries. This study is the first comprehensive assessment of care arrangements for people with dementia in those regions. Methods: A descriptive and comparative study of dementia care; caregiver characteristics, the nature of care provided, and the practical, psychological (Zarit Burden Interview, General Health Questionnaire) and economic impact upon the caregiver in 24 centres in India, China and South East Asia, Latin America and the Caribbean and Africa. Results: We interviewed 706 persons with dementia, and their caregivers. Most caregivers were women, living with the person with dementia in extended family households. One-quarter to one-half of households included a child. Larger households were associated with lower caregiver strain, where the caregiver was co-resident. However, despite the traditional apparatus of family care, levels of caregiver strain were at least as high as in the developed world. Many had cutback on work to care and faced the additional expense of paid carers and health services. Families from the poorest countries were particularly likely to have used expensive private medical services, and to be spending more than 10% of the per capita GNP on health care. Conclusions: Older people in developing countries are indivisible from their younger family members. The high levels of family strain identified in this study feed into the cycle of disadvantage and should thus be a concern for policymakers in the developing world. Copyright © 2004 John Wiley & Sons, Ltd.
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Incluye Bibliografía
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Incluye Bibliografía
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Incluye Bibliografía
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Chartergellus golfitensis West-Eberhard new species, is described from Central America and compared with C. zonatus Spinola, a species heretofore inadequately described.
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Includes bibliography
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Incluye Bibliografía