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21.
Two subspecies of Colorado chipmunk (state threatened and federal species of concern) occur in southern New MeXico: Tamias quadrivittatus australis in the Organ Mountains and T. q. oscuraensis in the Oscura Mountains. We developed a GIS model of potentially suitable habitat based on vegetation and elevation features, evaluated site classifications of the GIS model, and determined vegetation and terrain features associated with chipmunk occurrence. We compared GIS model classifications with actual vegetation and elevation features measured at 37 sites. At 60 sites we measured 18 habitat variables regarding slope, aspect, tree species, shrub species, and ground cover. We used logistic regression to analyze habitat variables associated with chipmunk presence/absence. All (100%) 37 sample sites (28 predicted suitable, 9 predicted unsuitable) were classified correctly by the GIS model regarding elevation and vegetation. For 28 sites predicted suitable by the GIS model, 18 sites (64%) appeared visually suitable based on habitat variables selected from logistic regression analyses, of which 10 sites (36%) were specifically predicted as suitable habitat via logistic regression. We detected chipmunks at 70% of sites deemed suitable via the logistic regression models. Shrub cover, tree density, plant proximity, presence of logs, and presence of rock outcrop were retained in the logistic model for the Oscura Mountains; litter, shrub cover, and grass cover were retained in the logistic model for the Organ Mountains. Evaluation of predictive models illustrates the need for multi-stage analyses to best judge performance. Microhabitat analyses indicate prospective needs for different management strategies between the subspecies. Sensitivities of each population of the Colorado chipmunk to natural and prescribed fire suggest that partial burnings of areas inhabited by Colorado chipmunks in southern New Mexico may be beneficial. These partial burnings may later help avoid a fire that could substantially reduce habitat of chipmunks over a mountain range. 相似文献
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Organophosphate-mediated inhibition of choline acetyltransferase activity in rat brain tissue 总被引:1,自引:0,他引:1
Administration of the organophosphate compound soman in rats resulted in an inhibition of choline acetyltransferase activity in almost all brain regions examined. Enzyme activity was inhibited by 20-50% in various brain regions 30 min after soman injection (94-120 micrograms/kg). Enzyme activity in two regions decreased with time to a near zero level by 3 h after injection. 相似文献
25.
Jessica L. Slack Corey P. Causey Paul R. Thompson 《Cellular and molecular life sciences : CMLS》2011,68(4):709-720
The recent approvals of anticancer therapeutic agents targeting the histone deacetylases and DNA methyltransferases have highlighted
the important role that epigenetics plays in human diseases, and suggested that the factors controlling gene expression are
novel drug targets. Protein arginine deiminase 4 (PAD4) is one such target because its effects on gene expression parallel
those observed for the histone deacetylases. We demonstrated that F- and Cl-amidine, two potent PAD4 inhibitors, display micromolar
cytotoxic effects towards several cancerous cell lines (HL-60, MCF7 and HT-29); no effect was observed in noncancerous lines
(NIH 3T3 and HL-60 granulocytes). These compounds also induced the differentiation of HL-60 and HT29 cells. Finally, these
compounds synergistically potentiated the cell killing effects of doxorubicin. Taken together, these findings suggest PAD4
inhibition as a novel epigenetic approach for the treatment of cancer, and suggest that F- and Cl-amidine are candidate therapeutic
agents for this disease. 相似文献
26.
本文阐述基于科学思维过程的英语文学教学策略,即英语文学作品以综合课程的形式应用于教学实践活动.其要点是从优秀文学作品中选取需要解决问题的情境,从跨学科的视角来审视作品中的矛盾和冲突.教师们通过分析这些问题情境教给学生科学的思维方法.其教学策略的重点在于提出问题和做出决策.这些用于跨学科教学策略的文学作品是关注真实世界的起点.生活中面临的两难问题通过基于科学思维的文学教学而获得理性的解释或合理的解决. 相似文献
27.
Truncating mutations in the Fanconi anemia J gene BRIP1 are low-penetrance breast cancer susceptibility alleles 总被引:21,自引:0,他引:21
Seal S Thompson D Renwick A Elliott A Kelly P Barfoot R Chagtai T Jayatilake H Ahmed M Spanova K North B McGuffog L Evans DG Eccles D;Breast Cancer Susceptibility Collaboration 《Nature genetics》2006,38(11):1239-1241
We identified constitutional truncating mutations of the BRCA1-interacting helicase BRIP1 in 9/1,212 individuals with breast cancer from BRCA1/BRCA2 mutation-negative families but in only 2/2,081 controls (P = 0.0030), and we estimate that BRIP1 mutations confer a relative risk of breast cancer of 2.0 (95% confidence interval = 1.2-3.2, P = 0.012). Biallelic BRIP1 mutations were recently shown to cause Fanconi anemia complementation group J. Thus, inactivating truncating mutations of BRIP1, similar to those in BRCA2, cause Fanconi anemia in biallelic carriers and confer susceptibility to breast cancer in monoallelic carriers. 相似文献
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DNA methylation profiling of human chromosomes 6, 20 and 22 总被引:24,自引:0,他引:24
29.
McCollough reported that following adaptation to (say) a red and black pattern of vertical stripes, alternating every few seconds with a green and black pattern of horizontal stripes, an orientation-contingent colour after-effect is observed when black and white gratings are viewed. Vertical gratings are tinged with green and horizontal gratings with pink. We have exploited colour constancy, the tendency for objects to appear constant in hue despite large changes in the spectral composition of the illuminant, to examine whether the colours observed on the McCollough effect test gratings are determined by the wavelength composition of the adaptation patterns or by their perceived colour. The key to this approach can be illustrated by Edwin Land's elegant demonstrations of colour constancy using 'Mondrian' displays. By embedding the adapting grating that is used to induce the McCollough effect within a Mondrian we show that the effect depends upon the wavelength of light coming from the grating, rather than the perceived colour. 相似文献
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