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991.
Júnior AF Gonçalves-Pires MR Silva DA Gonçalves AL Costa-Cruz JM 《Veterinary parasitology》2006,136(2):137-145
Canine strongyloidiasis is a parasitic infection caused by the nematode Strongyloides stercoralis and presents a great zoonotic potential. Its confirmation, using coproparasitological methods, is difficult. The detection of serum specific antibodies, however, may facilitate the diagnosis. The aims of this study were to determine the presence of S. stercoralis through the use of parasitological methods and to detect specific antibodies to the parasite in serum samples from domestic dogs by using the indirect fluorescent antibody test (IFAT) on slides and the enzyme-linked immunosorbent assay (ELISA). A total of 215 dogs of various breeds, from the cities of Uberlandia, Araxá and Campo Belo in the State of Minas Gerais, were examined and distributed according to age into the following groups: (I) 19 males and 20 females of 1-2 months old; (II) 11 males and 20 females of 2-month- to 1-year-old and (III) 41 males and 104 females, from 1 to 7 years old. Coproparasitological results showed that 63/215 (29.3%) of the dogs presented some kind of parasite, with two (0.9%) dogs (one from Araxá and the other from Uberlandia) passing S. stercoralis larvae in the feces. Serological results revealed antibodies to S. stercoralis in 45/215 (20.9%) of the dogs, with seropositivity rates of 0% (0/39) in Group I, 22.6% (7/31) in Group II, and 26.2% (38/145) in Group III. No serological cross-reactivity between S. stercoralis and hookworms or Ascaridae was found. Hookworm infections were seen in 31 dogs, but only one of these dogs (infected with both hookworm and Cystoisospora spp.) was S. stercoralis seropositive by IFAT. The present study demonstrated, for the first time, natural S. stercoralis infections in dogs diagnosed by coproparasitological and serological methods. It was concluded that the detection of specific antibodies to S. stercoralis by IFAT and ELISA may contribute to the diagnosis of canine strongyloidiasis. 相似文献
992.
Campos-Sánchez Jose Carlos Mayor-Lafuente Javier Guardiola Francisco A. Esteban María Ángeles 《Fish physiology and biochemistry》2021,47(5):1623-1643
Fish Physiology and Biochemistry - Inflammation is one of the main causes of loss of homeostasis at both the systemic and molecular levels. The aim of this study was to investigate in silico the... 相似文献
993.
Gomes Ana Lourenço Sílvia Santos Pedro M. Raposo Andreia Mendes Susana Gonçalves Sílvia C. Ferreira Susana M. F. Pombo Ana 《Aquaculture International》2021,29(3):1069-1090
Aquaculture International - The development of rearing protocols promoting the larval development, pre and post-metamorphosis are key for echinoculture. Mixed diets combining diatom with other... 相似文献
994.
Luis García Esteban Paloma de Palacios Francisco García Fernández Juan Antonio Martín Mar Génova Juan Ignacio Fernández-Golfín 《Wood Science and Technology》2009,43(7-8):679-690
The hygroscopicity and thermodynamic properties of buried juvenile Pinus sylvestris L. wood with an age of 1,170 ± 40 BP were compared with the corresponding values of juvenile wood of the same species from recently cut trees. The 35 and 50°C isotherms were plotted following the saturated salts method and subsequently fitted in accordance with the GAB model. The isotherms were then compared by means of the hysteresis coefficients. X-ray diffractograms were used to analyse the crystal structure of the cellulose. The effect of time on the buried wood caused hemicelluloses degradation and a decrease in the crystallinity index and the crystallite length, resulting in an increase in the proportion of amorphous zones. Because of this, the equilibrium moisture contents of the buried wood are higher than of the recent wood, both in adsorption and desorption. In terms of the thermodynamic properties, the heat involved is greater in the buried wood than in the recent wood. 相似文献
995.
Shan Shan Chang Bruno Clair Joseph Gril Hiroyuki Yamamoto Françoise Quignard 《Wood Science and Technology》2009,43(7-8):703-712
Wood deformation in the longitudinal and tangential directions induced by ethanol substitution and oven-drying was measured in normal wood (NW) and tension wood (TW) of chestnut (Castanea sativa Mill.) (TW with G-fibres) and simarouba (Simarouba amara Aubl.) (TW without G-fibres). The results show that with increased concentration of ethanol solution TW tends to contract, regardless of the presence or absence of G-fibres. In contrast, both NW and opposite wood expand at different rates in the longitudinal direction. These results are discussed and explained by the role of stress state at cell wall level. 相似文献
996.
M. K. da Silva Moço E. F. da Gama-Rodrigues A. C. da Gama-Rodrigues R. C. R. Machado V. C. Baligar 《Agroforestry Systems》2009,76(1):127-138
Agroforestry systems deposit great amounts of plant residues on soil and this leads to high levels of soil organic matter
content and has increased soil biodiversity and improved its conservation. This study compares the distribution of meso and
macrofaunal communities in soil and litter under cacao agroforestry systems and in a natural forest in the southern Bahia
state of Brazil. Soil and litter samples were obtained in September 2003, February 2004, and August 2004 in five cacao agroforestry
systems. The systems evaluated included: cacao renewed under Erythrina sp. (Erythrina poeppigiana) (CRE); cacao renewed under natural forest (Cabruca, CRF); an old cacao system under Erythrina sp. (OCE); an old cacao system under a natural forest system (Cabruca, OCF) and a cacao germplasm collection area (CGC).
As a reference soil and litter under a natural forest (NF) was included. Organisms were collected over a 15-day period with
a Berlese–Tullgren apparatus. The density and richness of total fauna varied distinctly according to sites, sampling time
and material sampled (soil and litter). 16,409 of fauna were recovered from soil and litter samples and the density of total
fauna was 2,094 individuals m−2 in the litter and 641 individuals m−2 in the soil. The richness was 11.8 in the litter and 7.5 in the soil. The cacao agroforestry systems adopted for growing
cacao in the southern Bahia region of Brazil have beneficial effects on the soil and litter faunal communities, and such systems
of cacao cultivation could be considered as a conservation system for soil fauna. The development of a litter layer resulted
in higher abundance and diversity of soil fauna. 相似文献
997.
Céline Leroy Sylvie Sabatier Novi Sari Wahyuni Jean-François Barczi Jean Dauzat Marilyne Laurans Daniel Auclair 《Agroforestry Systems》2009,77(1):37-47
In agroforestry systems, the distribution of light transmitted under tree canopies can be a limiting factor for the development
of intercrops. The light available for intercrops depends on the quantity of light intercepted by tree canopies and, consequently,
on the architecture of the tree species present. The influence of tree architecture on light transmission was analysed using
dynamic 3D architectural models. The architectural analysis of Acacia mangium and Tectona grandis was performed in Indonesian agroforestry systems with trees aged from 1 to 3 years. 3D virtual trees were then generated
with the AmapSim simulation software and 3D virtual experiments in which tree age, planting density, planting pattern and
pruning intensity varied were reconstructed in order to simulate light available for the crop. Canopy closure of trees was
more rapid in A. mangium than in T. grandis agroforestry systems; after 3 years the quantity of light available for A. mangium intercrops was three times lower than under T. grandis. Simulations with A. mangium showed that practices such as pruning and widening tree spacing enable to increase the total transmitted light within the
stand. On T. grandis, modification of the tree row azimuth resulted in changes in the spatial and seasonal distribution of light available for
the intercrops. These results are discussed in terms of agroforestry system management.
相似文献
Sylvie SabatierEmail: |
998.
A new spectrophotometric assay for the quantification of polyphenolic content has been validated. It is based on Prussian Blue method and adapted to microplate spectrophotometry. Prussian Blue reaction is critically dependent on reaction time, but microplate spectrophotometry permits exact measures of many samples at the same time. This new method is precise, reproducible, repeatable and exact. 相似文献
999.
Ciro Abbud Righi Paulo Maurício Lima de Alencastro Graa Carlos Clemente Cerri Brigitte Josefine Feigl Philip Martin Fearnside 《Forest Ecology and Management》2009,258(11):2535-2546
Estimates of greenhouse-gas emissions from deforestation are highly uncertain because of high variability in key parameters and because of the limited number of studies providing field measurements of these parameters. One such parameter is burning efficiency, which determines how much of the original forest's aboveground carbon stock will be released in the burn, as well as how much will later be released by decay and how much will remain as charcoal. In this paper we examined the fate of biomass from a semideciduous tropical forest in the “arc of deforestation,” where clearing activity is concentrated along the southern edge of the Amazon forest. We estimated carbon content, charcoal formation and burning efficiency by direct measurements (cutting and weighing) and by line-intersect sampling (LIS) done along the axis of each plot before and after burning of felled vegetation. The total aboveground dry biomass found here (219.3 Mg ha−1) is lower than the values found in studies that have been done in other parts of the Amazon region. Values for burning efficiency (65%) and charcoal formation (6.0%, or 5.98 Mg C ha−1) were much higher than those found in past studies in tropical areas. The percentage of trunk biomass lost in burning (49%) was substantially higher than has been found in previous studies. This difference may be explained by the concentration of more stems in the smaller diameter classes and the low humidity of the fuel (the dry season was unusually long in 2007, the year of the burn). This study provides the first measurements of forest burning parameters for a group of forest types that is now undergoing rapid deforestation. The burning parameters estimated here indicate substantially higher burning efficiency than has been found in other Amazonian forest types. Quantification of burning efficiency is critical to estimates of trace-gas emissions from deforestation. 相似文献
1000.
Cecilia A. Prez Martín R. Carmona Jos M. Faria Juan J. Armesto 《Forest Ecology and Management》2009,258(7):1660-1668
Lowland evergreen rainforests in southern Chile growing on highly productive soils and accessible sites have been subjected to traditional and industrial logging of valuable timber trees. Old-growth rain forests in this area are characterized by highly conservative N cycles, which results in an efficient N use of ecosystems. We hypothesize that different logging practices, by changing forest structure and species composition, can alter the quantity and quality (i.e. C/N ratio) of litterfall and soil organic matter and soil microbial processes that determine N storage and availability. To test this hypothesis we investigated chemical properties, microbial N transformations, N fluxes and N storage in soils of lowland evergreen rainforests of Chiloé Island after 10 years since industrial selective logging (ISL) and in stands subjected to traditional selective logging (TSL) by landowners in small properties. We compared them to reference unlogged old-growth stands (OG) in the same area. Tree basal area was more reduced in the stands subjected to ISL than to TSL. Litterfall inputs were similar in both logging treatments as in OG stands. This was due to greater biomass of understory species after logging. In TSL understory tree species determined a higher litterfall C/N ratio than ISL. We found higher soil N availability and content of base cations in surface soils of logged forests than in OG. The litter horizon of OG forest had significantly higher rates of non-symbiotic N fixation than logged forests. In the ISL treatment there was a trend toward increasing soil denitrification and significantly higher NO3–N/Nt ratio in spring waters, which led to a stronger δ15N signal in surface and deep soils. We conclude that massive understory occupation by the shade-intolerant native bamboo Chusquea quila in ISL led to enhanced litter quality (lower C/N ratios) relaxing the tightness of the N cycle, which increased soil N availability leading to a higher proportion of nitrate in spring waters and higher gaseous N losses. In contrast, under TSL a higher litterfall C/N ratio slowed decomposition and net N mineralization rates thus reducing the chances for N losses, and enhancing C and N storage in soil. We suggest that sustainable logging practices in these rain forests should be based on lower rates of canopy removal to enhance colonization of the understory by shade-tolerant trees, which are associated with a more efficient N cycle. 相似文献