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31.
This study evaluated the efficacy of intramammary infusion of ceftiofur hydrochloride for the treatment of intramammary infections present at the last milking of lactation and for prevention of new intramammary infections during the nonlactating period. Cows were randomly assigned to five treatments (untreated negative control, 125, 250, and 500 mg of ceftiofur, and a positive control group receiving 300 mg cephapirin benzathine). A dose of 125 mg of ceftiofur per mammary quarter was effective for treatment of existing infections present at the time of milk cessation, but only the 500-mg dose of ceftiofur per mammary quarter was effective for both treatment of existing intramammary infections at the time of milk cessation and for prevention of new intramammary infections during the nonlactating period.  相似文献   
32.
The effects of protein quality, protein content, ingredients, and baking process of flour blends on hearth loaves were studied. The flour blends varied in protein composition and content. Flours of strong protein quality produced hearth loaves with larger loaf volume, larger bread slice area, and higher form ratio (height/width) than flours of weak protein quality. The effect of protein content on hearth loaf depended on the size distribution of the proteins. Increasing protein content was associated with increased percentage of the largest glutenin polymers, and loaf volume and slice area increased significantly. The form ratio, however, remained unchanged with increasing flour protein content. Strong protein quality flours tolerated addition of whole meal flour better than weak protein quality flours. Increased amount of flour with strong protein quality improved hearth bread characteristics to a larger extent than increased protein content. Diacetyl tartaric acid ester of monoglycerides (DATEM) improved hearth bread characteristics, but the effect was small compared with the effect of protein composition.  相似文献   
33.
A model was developed for predicting site index (SI) values and top height growth of lodgepole pine in northern Sweden. Data on 169 experimental plots from 61 experiments were used for model construction. Six dynamic site equations derived using the generalized algebraic difference approach (GADA) were tested. All of the equations estimate height and SI values on the basis of a known height and total age, and are base-age invariant. Unbiased parameter estimates were obtained by non-linear modelling without accounting for autocorrelation of residuals. The special formulation of the Hossfeld model and the GADA-transformed logistic function produced the most reliable SI curves. The Hossfeld model is recommended as it did not produce extreme outlying estimates for young stands. The developed model is polymorphic with variable asymptotes and can predict SI and dominant height growth for lodgepole pine between 20 and 50 years old.  相似文献   
34.
Snake or honeybee envenomation can cause substantial morbidity and mortality, and it has been proposed that the activation of mast cells by snake or insect venoms can contribute to these effects. We show, in contrast, that mast cells can significantly reduce snake-venom-induced pathology in mice, at least in part by releasing carboxypeptidase A and possibly other proteases, which can degrade venom components. Mast cells also significantly reduced the morbidity and mortality induced by honeybee venom. These findings identify a new biological function for mast cells in enhancing resistance to the morbidity and mortality induced by animal venoms.  相似文献   
35.
36.
We investigated the stand structure of ten young urban woodlands established in Southern Scandinavia during the 1970s and 1980s according to the ecological approach, which advocated the use of many different species of trees and shrubs to create complex canopy structures as soon as possible after establishment to promote recreation and biodiversity. Tree height and live crown depths were measured and analysed using a combination of quantitative and qualitative approaches to assess the forest structure in terms of canopy stratification. The results show that the current canopy structures could be classified into seven different two- and three-layered structural types which had evolved as a combination of differences in management frequency and the initial species composition. Two layered stands were characterized by lower management frequency compared to three layered stands and stands in transition to three layers. They were also established with a lower proportion of understory species and a higher proportion of shade tree species. The total number of species at the establishment did not influence how stands were categorized. The two main conclusions are that recurrent thinnings is a key factor for successful management of young, species rich forest plantations, and that species composition can increase the resilience towards management neglect. Instead of aiming at maximising total species number it is more reasonable to focus on a few key species in each layer. We conclude that three-layered canopy structures can be created already after twenty five years, which should encourage planners and practitioners to incorporate multilayered stands in future urban woodland creation.  相似文献   
37.
Although the sentences that we hear or read have meaning, this does not necessarily mean that they are also true. Relatively little is known about the critical brain structures for, and the relative time course of, establishing the meaning and truth of linguistic expressions. We present electroencephalogram data that show the rapid parallel integration of both semantic and world knowledge during the interpretation of a sentence. Data from functional magnetic resonance imaging revealed that the left inferior prefrontal cortex is involved in the integration of both meaning and world knowledge. Finally, oscillatory brain responses indicate that the brain keeps a record of what makes a sentence hard to interpret.  相似文献   
38.
一头猪经过繁殖、出生、饲养、肥育后到成为我们的盘中餐——这是一个在随后25年中将不会改变的商品肉猪生产过程。然而,将来猪肉生产机构将面临越来越多的挑战。要实现目标的优先权不同国家之间可能不尽相同,但是有一点在全球范围内是明白无误的,即成本效益是至关重要的。  相似文献   
39.
In this longitudinal observational study, 118 growing Newfoundland dogs were followed with sequential radiographic examination of the right front limb, which were scheduled at ages 3, 4, 6, 12, 18, and 24 months to record evidence of skeletal changes. All affected dogs had evidence of changes at 6 months and dogs included in this study had radiographic examination at 6 months and at least two other scheduled examinations that included either 4 or 12 months. The dogs were privately owned and had individualized nutrition and environment with no maintenance protocol required by the project leaders. Irregularities in bone remodeling in the distal radius and ulna were seen in radiographs of 54 of 118 (45.8%) dogs. These irregularities differ from changes previously described in the Newfoundland dog. The reported irregularities were seen as islands of reduced opacity outlined by thickened, radiopaque osseous trabeculae, which were aligned with the axis of stress. All the 54 dogs with irregularities during some phase of development consistently had changes at 6 months of age. Reorganization of the changes in the bone was slow, and residual changes were visible at 18-24 months of age in many cases. The significance of these findings may lie in their potential for misinterpretation if they had been discovered in the presence of clinical signs such as any lameness or growth arrest. Radiographic appearance indicates disturbances in the bone maturation. The etiopathogenesis is unclear. Nutritional, environmental and genetic factors have to be studied.  相似文献   
40.
Journal of Pest Science - Biological control, or biocontrol, is the exploitation of living agents (incl. viruses) to combat pestilential organisms (incl. pathogens, pests, and weeds) for diverse...  相似文献   
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