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81.
Background
In heterogeneous environments, sex-biased dispersal could lead to environmental adaptive parental effects, with offspring selected to perform in the same way as the parent dispersing least, because this parent is more likely to be locally adapted. We investigate this hypothesis by simulating varying levels of sex-biased dispersal in a patchy environment. The relative advantage of a strategy involving pure maternal (or paternal) inheritance is then compared with a strategy involving classical biparental inheritance in plants and in animals. 相似文献82.
TNF inhibitors are currently considered both effective and cost-effective in patients with active rheumatoid arthritis (RA),
particularly in patients who have not responded fully to methotrexate. There is substantial doubt about the cost-effectiveness
of TNF inhibitors as initial treatment for active RA. New data from the National Data Bank for Rheumatic Diseases now question
the current consensus in methotrexate failures. The data suggest that in routine clinical practice TNF inhibitors provide
only modest incremental benefits over best conventional therapy. If confirmed, these observational studies suggest that the
economic argument underpinning the widespread use of TNF inhibitors in established RA is unsustainable. 相似文献
83.
Background
DNA Microarrays have become the standard method for large scale analyses of gene expression and epigenomics. The increasing complexity and inherent noisiness of the generated data makes visual data exploration ever more important. Fast deployment of new methods as well as a combination of predefined, easy to apply methods with programmer's access to the data are important requirements for any analysis framework. Mayday is an open source platform with emphasis on visual data exploration and analysis. Many built-in methods for clustering, machine learning and classification are provided for dissecting complex datasets. Plugins can easily be written to extend Mayday's functionality in a large number of ways. As Java program, Mayday is platform-independent and can be used as Java WebStart application without any installation. Mayday can import data from several file formats, database connectivity is included for efficient data organization. Numerous interactive visualization tools, including box plots, profile plots, principal component plots and a heatmap are available, can be enhanced with metadata and exported as publication quality vector files. 相似文献84.
85.
86.
Atrial natriuretic factor alters autonomic interactions in the control of heart rate in conscious rats 总被引:2,自引:0,他引:2
U Ackermann J Khanna T G Irizawa 《Canadian journal of physiology and pharmacology》1988,66(7):930-936
Regulation of heart rate was studied in rats receiving either i.v. saline at 64 microL/min or synthetic 28-residue rat atrial natriuretic peptide (ANF) at a dose sufficient to decrease mean arterial blood pressure by 10%. Autonomic influences were deduced from steady-state heart rate responses of each group to propranolol, atropine, or propranolol and atropine combined. A multiplicative model of heart rate control was used to derive quantitatively from the data the modulation of intrinsic heart rate by sympathetic and parasympathetic mechanisms. Animals receiving ANF showed a lower heart rate than control animals. This relative bradycardia was abolished by atropine. Blocking of sympathetic effects with propranolol had no effect on basal heart rate in either group, and atropinization led to significant increases in heart rate in both groups of rats. Mathematical analysis of the results showed that the bradycardia produced by ANF was due predominantly to a reduced intrinsic heart rate and to enhanced vagal inhibition of postganglionic sympathetic activity. Parasympathetic contribution to heart rate in the absence of sympathetic activity was negligible in control rats and small during ANF. We conclude that the major influences of ANF on heart rate control are a decrease of intrinsic heart rate and enhanced parasympathetic inhibition of postganglionic presynaptic sympathetic activity. 相似文献
87.
Emin Oguzhan Oguz Hayati Yuksel Yasar Enli A. Cevik Tufan Gunfer Turgut 《Biological trace element research》2010,133(3):335-341
Copper is an essential trace element that is extremely toxic to organisms and organs at high doses. We have investigated the
histological and biochemical effects of a toxic dose of copper sulfate on the liver of term Ross broiler chicks. Fertilized
eggs were divided into three groups: experimental, injected with 50 mcg/0.1 ml copper sulfate in the air chambers on day 1;
sham, injected with 0.1 ml saline; and control, no injection. Term chicks were killed and their livers investigated histologically,
with hematoxylin–eosin-stained sections examined under light microscopy, and biochemically, for malondialdehyde and glutathione
levels. Histological examinations showed copper-treated samples with granular degeneration and necrosis of hepatocytes and
impairment to the cell lining of the remark cords. The samples had a congestive appearance, with blood in the vena centralis
and sinusoids, slight connective tissue increase, and lymphocyte infiltration. Control and sham group sections had normal
appearances. As oxidative damage parameters, in the copper-treated group, malondialdehyde levels were increased and glutathione
levels decreased. In the sham and control groups, there were no significant differences. At this toxic dose, copper sulfate
shows oxidative damage according to the histology of term chick liver that are confirmed biochemically by the changes in malondialdehyde
and glutathione levels. 相似文献
88.
V T Kondakov A B Okulov M A Filippkin R Z Tandilava I U Artamonov O A Voronenko A N Sazonov 《Vestnik rentgenologii i radiologii》1991,(4):31-35
The paper is concerned with analysis of the results of intraoperative phlebotesticulography, performed in 50 patients with varicocele of degree I-II during Ivanissevich's operation. The effect of surgical intervention was shown to depend upon the quality of ligation of the testicular vein, some parts of which are anastomosed between themselves. The localization of this anastomosis is revealed by means of intraoperative phlebotesticulography, which permits increasing the results of surgical treatment and predicting a course of a postoperative period. 相似文献
89.
The purpose of this review is to provide a global perspective on Oncorhynchus salmonine introductions and put-and-take fisheries based on modern stocking programs, with special emphasis on freshwater
ecosystems. We survey the global introductions of nine selected salmonines of the genus Oncorhynchus: golden trout, cutthroat trout, pink salmon, chum salmon, coho salmon, masu/cherry salmon, rainbow trout/steelhead, sockeye
salmon/kokanee, and chinook salmon. The information is organized on a geographical basis by continent, and then by species
and chronology. Two different objectives and associated definitions of ‘success’ for introductions are distinguished: (a)
seed introduction: release of individuals with the purpose of creating a wild-reproducing, self-sustaining population; and
(b) put-and-take introduction: release of individuals with the purpose of maintaining some level of wild population abundance,
regardless of wild reproduction. We identify four major phenomena regarding global salmonine introductions: (1) general inadequacy
of documentation regarding introductions; (2) a fundamental disconnect between management actions and ecological consequences
of introductions; (3) the importance of global climate change on success of previous and future introductions; and (4) the
significance of aquaculture as a key uncertainty in accidental introductions. We conclude this review with a recognition of
the need to terminate ongoing stocking programs for introduced salmonines worldwide. 相似文献
90.