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321.
Mitchell V Palmer William C Stoffregen Douglas G Rogers Amir N Hamir Juergen A Richt Douglas D Pedersen W Ray Waters 《Journal of veterinary diagnostic investigation》2004,16(3):219-222
West Nile virus (WNV) infection in 4 reindeer (Rangifer tarandus) resulted in lymphohistiocytic encephalomyelitis within the medulla oblongata and cervical spinal cord. Immunohistochemistry revealed WNV antigen within neurons and among mononuclear cell infiltrates. These represent the first known cases of clinical WNV infection in Cervidae. Clinical signs and lesions were similar to those described in horses. Nucleotide sequence of a 768-bp region of the WNV E-glycoprotein gene revealed 1 nucleotide mutation, which resulted in a single amino acid substitution from a serine to a glycine (position 227 of E-glycoprotein) when compared with the prototype WNV-NY99 strain (isolated from Bronx zoo flamingo 382-99). 相似文献
322.
NDVI-Based Lacunarity Texture for Improving Identification of Torreya Using Object-Oriented Method 总被引:1,自引:0,他引:1
Normalized Difference Vegetation Index (NDVI) is a very useful feature for differentiating vegetation and non-vegetation in remote sensed imagery. In the light of the function of NDVI and the spatial patterns of the vegetation landscapes, we proposed the lacunarity texture derived from NDVI to characterize the spatial patterns of vegetation landscapes concerning the “gappiness” or “emptiness” characteristics. The NDVI-based lacunarity texture was incorporated into object-oriented classification for improving the identification of vegetation categories, especially Torreya which was the targeted tree species in the present research. A three-level hierarchical network of image objects was defined and the proposed texture was integrated as potential sources of information in the rules base. A knowledge base of rules created by classifier C5.0 indicated that the texture could potentially be applied in object-oriented classification. It was found that the addition of such texture improved the identification of every vegetation category. The results demonstrated that the texture could characterize the spatial patterns of vegetation structures, which could be a promising approach for vegetation identification. 相似文献
323.
Much of the focus of agricultural improvement efforts in recent decades has been on modifying crops’ genetic potential more
than on improving cropping practices and production systems. Certainly, this genocentric approach has made significant contributions
to food production in certain parts of the world under the banner of “the Green Revolution.” Yields have been raised substantially
through varietal improvements and the increased use of inputs, including energy, agrochemicals, and delivering more water
to crops through irrigation technology. In the past two decades, however, gains from this strategy have decelerated, with
increasing economic and environmental costs of this input-dependent approach. Accordingly, there is reason to consider what
can be accomplished by making optimizing changes in crops’ growing environments both above ground and, especially, below ground.
The System of Rice Intensification (SRI) developed in Madagascar has been showing that, by modifying crop, soil, water and
nutrient management, it can under most of the circumstances evaluated thus far raise of the productivity of land, water, seeds,
capital, and labor used for irrigated rice production. This article summarizes and reflects on the evidence provided in the
preceding articles in this special issue. It draws on the scientific evaluations and field experience from Asia, Africa, and
Latin America to offer some conclusions about the methodology known as SRI. Since this methodology is still evolving, no final
assessment is possible. Much more research and evaluation remain to be done, and there will be further modifications and refinements
since making adaptations to local conditions is regarded as intrinsic to the methodology. Further improvements in SRI will
come from both researchers and farmers, with the latter considered as partners rather than simply adopters. This is consistent
with SRI’s representing a paradigm shift more than a fixed technology. The article identifies a number of areas for additional
research that can probably improve factor productivity still further. 相似文献
324.
325.
Afshar S Heidari R Farshid AA Ilkhanipour M 《Pakistan journal of biological sciences: PJBS》2008,11(13):1742-1745
The aim of this study was to evaluate the effects of acute exposure to various doses of fenitrothion (FNT) on level of serum glucose, total protein, triglycerides (TG), total cholesterol (TC) and some hematological parameters. The study was conducted on 8-week-old male Wistar rats that divided into four groups (three experimental groups and one control group), were treated orally with different doses (25, 50 and 100 mg kg(-1)) of fenitrothion for 28 consecutive day. After treatment, blood samples were collected for biochemical and hematological studies. Present results demonstrated that exposed groups led to significant dose-dependent increase in serum glucose and cholesterol levels. Significant decrease was observed in some hematological parameters [Red Blood Cell (RBC) counts, Hemoglobin (Hb), Haematocrite (Ht) and Mean Corpuscular Hemoglobin (MCH) values]. Serum total protein and triglycerides were also decreased not significantly in exposed groups when compared with control. Generally, the degrees of observed variations were found to be dose dependent. 相似文献
326.
A study was conducted at Bunda Fish Farm to evaluate the effects of dietary lipid levels on reproductive performance of Oreochromis karongae. Fish were reared in 12 hapas for 86 days, with four experimental diets containing 8.28%, 10.17%, 12.09% and 14.05% levels of lipid, replicated three times. At the end of the experiment, O. karongae fed 10.17% and 12.09% lipid had the highest absolute fecundity (237.5 ± 6.50 and 271.3 ± 26.19, respectively) as compared with fish fed on 8.28% and 14.05% lipid levels (90.3 ± 46.3 and 143.7 ± 30.8 respectively). Higher number of spawns (5) were observed in fish fed on diets containing crude lipid of 10.17%. We can assume also that diets of 10.17% lipid are not costly as those of 12.09% or 14.05% lipid. It was found that the size of eggs depended on the number of eggs spawned by the female fish, as the number of eggs increased, the weight of eggs and mean egg diameter decreased. There were no significant differences (P > 0.05) among treatments in terms of relative fecundity. Based on these findings, it is recommended that diets containing crude lipid of 10% should be fed to broodstock for optimum reproductive performance of O. karongae. 相似文献
327.
Holden KM Browning GF Noormohammadi AH Markham PF Marenda MS 《Comparative immunology, microbiology and infectious diseases》2012,35(2):129-138
Avian pathogenic Escherichia coli (APEC) strains have multiple iron-uptake systems that facilitate adaptation to iron-restricted environments and are believed to assist in colonisation of the host. These systems include several TonB-dependent transporters of ferri-siderophores encoded by the chromosome and the large virulence plasmid common to APECs. The tonB gene of the virulent APEC strain E956 was replaced with a selectable antibiotic resistance marker using Lambda Red recombinase mutagenesis. The phenotype of the ΔtonB E956 mutant was compared to the parent strain under various culture conditions and in chickens experimentally infected via the respiratory route. The mutant was resistant to streptonigrin, impaired in its ability to adapt to growth in iron-depleted medium and had greater tolerance of oxidative stress than the parental strain. The mutant was avirulent in chickens, did not affect the growth of chicks and colonisation was mostly limited to the trachea. This study has demonstrated that TonB is essential for virulence in APEC. 相似文献
328.
The development of preimplantation mammalian embryos in vitro is less than optimal. Follicular fluid and cumulus cells have both been used independently, to improve preimplantation embryo quality in culture. This study was undertaken to evaluate the influence of a cumulus cell monolayer in human follicular fluid on mouse early embryo development in vitro. One-cell embryos were obtained from NMRI mice after superovulation with eCG and hCG. Cumulus cells were prepared from mouse egg-cumulus mass. These cells were separated from red blood cells using a Percoll gradient. Follicular fluid was collected from patients undergoing an IVF program during oocyte pick-up. The cumulus cell monolayer was prepared in follicular fluid (FC) and Ham's F10 (HC). Mouse one-cell embryos were cultured in FC, HC, Ham's F10 (HF) and follicular fluid (FF) for 120 h. Only 10.5% of embryos passed the two-cell block in HF. However, the proportions of embryos passing the two-cell block were 23.1%, 21.4% and 68.5% in FF, HC, and FC treatments, respectively; which were significantly different from HF (p<0.05). The differences between FC and the two other treatments were also significant (p<0.001). In FC, 33.7% of one-cell embryos continued to grow to the blastocyst stage whereas only 2.1% and 1.9% of one-cell embryos in FF and HC reached this stage and no embryos developed to blastocyst in HF. The proportion of blastocysts in FC was significantly higher than all other treatments (p<0.001). It can be concluded that follicular fluid and cumulus cells in monolayer form synergistically improve the early embryo culture condition. 相似文献
329.
Shahmoradi AH Arefpajohi R Tadayon K Mosavari N 《Tropical animal health and production》2008,40(3):169-173
Paratuberculosis is an important disease of ruminants with a worldwide distribution. In developing countries where funding
constraints challenge establishment of control schemes, large losses are incurred on cattle farmers due to paratuberculosis.
In this study, faecal specimens from Holstein-Friesian cows with progressed and moderate clinical paratuberculosis (N = 223)
from 13 dairy farms in Isfahan, Central Iran, were subjected to bacterial culture. Culture growth diagnostic for M. avium subsp. paratuberculosis was found in cattle from nine of the 13 farms and in 71 of the cattle studied. These results illustrate the emergence of
PTb in this region, and they imply that PTb should be given a higher priority for veterinary measures. 相似文献
330.