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991.
Gomes Pöppl Á Costa Valle S Hilário Díaz González F de Castro Beck CA Kucharski LC Silveira Martins Da Silva R 《Veterinary research communications》2012,36(1):81-84
Estrus cycle is a well recognized cause of insulin resistance in bitches. The insulin receptor (IR) as well as the insulin-like
growth factor-I receptor belong to the same subfamily of tyrosine kinase (TK) receptors. The objective of this study was to
evaluate basal TK activity in muscle tissue of bitches during the estrus cycle. Twenty-four bitches were used in the study
(7 in anestrus, 7 in estrus, and 10 in diestrus). Muscle samples, taken after spaying surgery to determine TK activity, were
immediately frozen in liquid nitrogen and then stored at −80°C until the membranes were prepared by sequential centrifugation
after being homogenized. TK activity was determined by Poly (Glu 4:Tyr 1) phosphorylation and expressed in cpm/μg of protein.
TK activity was significantly lower (P < 0.001) in the animals in estrus (104.5 ± 11.9 cpm/μg of protein) and diestrus (94.5 ± 16.9 cpm/μg of protein) when compared
with bitches in anestrus (183.2 ± 39.2 cpm/μg of protein). These results demonstrate, for the first time, lower basal TK activity
in the muscle tissue of female dogs during estrus and diestrus, which may represent lower insulin signaling capacity, opening
a new field of investigation into the molecular mechanisms of insulin resistance in dogs. 相似文献
992.
Héctor A. Bahamonde P. L. Peri R. Alvarez A. Barneix A. Moretto G. Martínez Pastur 《Agroforestry Systems》2012,84(3):345-360
The role of environmental variables on litter decomposition and its nutrient release in Nothofagus antarctica forest in Patagonia is poorly understood. Moreover, in these forests under silvopastoral use there are few antecedents. Litter
decomposition and nutrient release of grasses and tree leaves were evaluated under different crown cover and two site quality
stands during 480 days. Organic matter decomposition varied with crown cover for both types of litter, achieving mean values
of 23 and 34% for maximal and minimal crown cover, respectively. Total transmitted radiation was the main environmental factor
explaining 61 and 49% of the variation of grass and tree leaves decay rates, respectively. N, P, and Ca were mineralized during
first 60 days in decomposing tree leaves and then immobilized without differences between crown cover. The K was immobilized
during the evaluated period. In decomposing grass leaves the results varied according to site quality and time. There was
a tendency of nutrient mineralization at the first 120 days and then immobilization. The removal of trees for silvopastoral
use of N. antarctica may increase litter decomposition by changing the microclimate, but nutrients release or immobilization was mainly affected
for their concentration in decomposing material. 相似文献
993.
Phelipe M. Oller Costa Cristina M. Souza-Motta Elaine Malosso 《Agroforestry Systems》2012,85(1):195-203
Microbial population and activity can be influenced by changes in the physical and chemical conditions of the soil. The objective of this study was to compare fungal diversity under different agricultural management systems and associated differences in soil properties. This research was carried out in three areas, representing the Atlantic Forest, AFS and cassava (Manihot esculenta Crantz) monoculture system. Five composite samples were collected during the rainy and dry seasons from each area. Using the composite soil samples, fungal isolation was carried out using a serial dilution technique. Physical, chemical and DGGE analyses of the filamentous fungi community were performed. The fungal isolation data were used to calculate ecological indices of diversity, species richness, equitability, dominance, similarity and density. In general, Atlantic Forest soil presented the highest ecological indices followed by the AFS. The DGGE technique revealed that the structure of the soil mycobiota of the Atlantic Forest and AFS are more than 50% similar. The data indicate that the similarity of the structure and composition of soil mycobiota between AFS and Atlantic Forest is mainly due to the conservation of above-ground plant diversity, and the conservation of soil characteristics can be attributed to the absence of pesticides and fertilizers. 相似文献
994.
Eucalypt (Eucalyptus spp.) tree farming is a source of income for many smallholders in developing and emerging countries and critical to the resource
supply of many pulp and paper companies. These companies rely on smallholders adopting tree farming, sometimes by offering
a contract. This paper reports a study from four regions of Thailand, where smallholder eucalypt tree farming is important,
which investigated what characteristics of smallholders were associated with greater adoption of tree farming. A total of
461 eucalypt tree farmers and 171 non-tree farmers were randomly selected and surveyed in these regions, using a door-to-door
household survey. A logit analysis corroborated hypotheses about the drivers of adoption. Qualitative analyses were used to
inform interpretation of the quantitative results and shed light on the role of eucalypt tree farming in smallholders’ livelihood.
Results demonstrate that those with suitable land available are more likely to adopt eucalypt tree farming than others. In
addition, perception of land tenure security matters in the adoption of tree growing, but holding a formal land tenure document
does not. Adoption of eucalypt tree farming in Thailand is not part of a land use intensification strategy. Instead, eucalypts
are used as an alternative crop for low productivity land, on which eucalypts are the most profitable crop. Eucalypt tree
farming also gives smallholders an opportunity to diversify their income. In addition, this alternative land use has the advantage
of requiring low labour inputs between planting and harvest. This is particularly advantageous for many tree growers who have
off-farm income or rely on hired labour for farming their land. 相似文献
995.
Ana Isabel Moreno-Calles Alejandro Casas Eduardo García-Frapolli Ignacio Torres-García 《Agroforestry Systems》2012,84(2):207-226
Agroforestry systems (AFS) derived from the cactus forest “chichipera” and cultivated with “milpa”, the traditional multi-crop
system of maize-beans-squash were studied in the Tehuacán Valley, Mexico. Plant management types practiced by people, role
of agricultural and forest resources in households’ subsistence, and consequences of changes in AFS were investigated through
ethnobotanical, ecological, and economic approaches. People maintain in this AFS 122 plant species that provide useful products
for 14 different purposes. Nearly 90% of useful plants are native to the region, representing 54% of all plant species recorded
in the chichipera forest. Management strategies were identified occurring on 63 species at landscape, parcel, and individual
plant levels. About 67% of managed plant species are left standing during clearance of vegetation; 35% are transplanted to
the parcels’ surrounding area, 32% receive particular protection, and 10 species from other areas are cultivated inside the
fields. During years of higher rainfall (~745 mm) AFS supply nearly 75% of the maize grain and 50% of the maize straw used
as fodder by households. AFS with intermediate vegetation cover have higher economic value than monocultures and forest. However,
plots with low forest cover and monocultures are progressively more common as consequence of socio-cultural processes. Local
traditional ecological knowledge and management techniques are crucial for managing resilience of these AFS. 相似文献
996.
997.
Mustapha Bakry Mohammed S. Lamhamedi Jean Caron Hank Margolis Abdenbi Zine El Abidine M’Hammed Bellaka Debra C. Stowe 《New Forests》2012,43(3):267-286
The morpho-physiological quality of seedlings is negatively affected by the wide scale use of forest soils as substrates in
developing countries. With the objective of finding long-term sustainable supply of growing media, compost was produced from
shredded branches of three fast growing species (Acacia cyanophylla (AA), Acacia cyclops (AS) and Eucalyptus gomphocephala (EG). The composting process covered three different periods over the course of a year. Pile temperatures were monitored daily
and the composts were routinely sampled and analyzed for 19 chemical variables. Although composting is feasible year-round
in arid climates, compost produced in the humid cool conditions of autumn, winter and early spring reaches the maturation
phase more quickly than compost produced under hot, dry summer conditions. It also requires less turning and water. The evolution
of the composting process and quality of the final product can be assessed using three chemical variables (C/N, pH, EC). Seed
germination rates in the three types of compost were similar to that in a peat:vermiculite substrate and vigorous high quality
seedlings were produced in the two acacia composts. However, compost-grown seedlings had significantly smaller shoots and
root systems than those produced in peat substrate. Principal components analyses showed that the quality of a compost-based
substrate is reproducible and that its final chemical composition can be predicted from its raw organic materials. The EG composts had higher pH than the acacia composts, whereas the AA and EG composts were higher in mineral salts than the AS. 相似文献
998.
The success of direct seeding, as a low-cost approach to forest restoration, varies with tree species and seed characteristics.
A system to predict which tree species are likely to be suitable for direct seeding would therefore be useful for improving
forest restoration projects. Therefore, this study aimed to determine the effects of seed traits on the success of direct
seeding to restore tropical forest in southern Thailand. Seeds of 19 indigenous lowland tropical forest tree species were
collected, from both the east and west sides of the Thailand peninsular and the following parameters measured: seed size,
shape, coat thickness and moisture content. Field trials were established to determine seed germination rates and to calculate
a “direct seeding suitability score” for each species, which combined seedling establishment and growth rates. Seed size,
shape and moisture content were associated with germination percentage. Species with higher seedling survival tended to have
large or intermediate-sized seeds, round or oval seeds and seeds with low or medium moisture content. Only seed coat thickness
was significantly correlated with the suitability score (r = 0.65, p < 0.01). Seed coat thickness >0.4 mm coincided with higher rank suitability score. These conditions successfully predicted
the success or failure of direct seeding for 15 out of 19 species tested. Eight tree species are recommended as suitable for
restoring lowland evergreen forest ecosystems in southern Thailand, by direct seeding. 相似文献
999.
Costa LM Zahler-Rinder M Ribeiro MF Rembeck K Rabelo EM Pfister K Passos LM 《Veterinary parasitology》2012,188(1-2):160-163
This paper reports the development and use of a Real Time PCR for detection of Babesia canis canis, B. canis rossi, and B. canis vogeli in endemic areas of Brazil. The sequences of the internal transcribed spacer (ITS) of several organisms were aligned and five primers and four probes were designed for amplification of a fragment (around 125 bp) which differentiates subspecies of B. canis. Blood samples collected from dogs living in farms in three distinct rural regions within the State of Minas Gerais (Lavras, Belo Horizonte and Nanuque) were tested. Blood samples had been collected during a dry season (Lavras, n=100; Belo Horizonte, n=50; Nanuque, n=102); the dogs were re-sampled in the subsequent rainy season (Lavras, n=71; Belo Horizonte, n=29; Nanuque, n=66). From each sample, DNA was extracted and Giemsa stained smears were microscopically examined for direct detection of Babesia parasites. B. canis vogeli was the only subspecies found, with an overall prevalence of 9.9% during the dry season and 10.8% during the rainy season. Dogs living in Nanuque and Belo Horizonte showed significantly higher prevalence rates than those living in Lavras (13.7%, 12.0% and 5.0%, respectively). The Real Time PCR developed proved to be appropriate to detect B. canis subspecies in endemic areas. 相似文献
1000.
de Moura MQ Jeske S Gallina T Borsuk S Berne ME Villela MM 《Veterinary parasitology》2012,184(2-4):359-361
Public parks, especially in developing countries, are places where stray animals run free and may contaminate the environment with different species of parasites. In an evaluation of environmental sanitation of these sites, soil samples were collected monthly from public parks in the Pelotas city, Rio Grande do Sul State, Southern Brazil. Eggs of the nematode Lagochilascaris sp. were found in a public playground. This is the first report of identification of this nematode in Southern Brazil. 相似文献