Dipole moments of highly vibrationally excited water     

Callegari A  Theulé P  Muenter JS  Tolchenov RN  Zobov NF  Polyansky OL  Tennyson J  Rizzo TR 《Science (New York, N.Y.)》2002,297(5583):993-995

The intensity of water absorption in the region of the solar spectrum plays a dominant role in atmospheric energy balance and hence strongly influences climate. Significant controversy exists over how to model this absorption accurately. We report dipole moment measurements of highly vibrationally excited water, which provide stringent tests of intensities determined by other means. Our measurements and accompanying calculations suggest that the best currently available potential and dipole surfaces do not accurately model intensities in the optical spectrum of water.  相似文献   

对昆明白杂种鼠胚胎体外培养的实验研究──2细胞期至卵圆筒期     

李云龙  连正兴 《东北农业大学学报》1994,25(1):75-80

利用ＣＭＲＬ—１０６６和国产其它药品对昆明白杂种小鼠２—细胞期的胚胎，进行了体外培养试脸，成功地将２—细胞胚胎在体外培养条体下，使之生长发育到卵圆筒阶段。从２—细胞期开始计算，囊胚形成率为７０％，卵化率为３０％，附植率为２％，卵圆筒期胚胎形成率为１％。试验发现，把２—细胞期小鼠胚胎体外培养到卵圆筒期比体外发育到同阶段推迟１～２天，此卵圆筒期胚胎的形成率与国外报道的２４％相比仍然很低，其原因估计可能为：１）小鼠的品种；２）国产药物的纯度；３）ＣＯ２条件不同而造成。  相似文献   

Agroenvironmental determinants associated with the presence of antimicrobial-resistant Escherichia coli in beach waters in Quebec, Canada     

Turgeon P  Michel P  Levallois P  Chevalier P  Daignault D  Crago B  Irwin R  McEwen SA  Neumann NF  Louie M 《Zoonoses and public health》2011,58(6):432-439

Exposure to microorganisms resistant to antimicrobials may constitute a health risk to human populations. It is believed that one route of exposure occurs when people engage in recreational activities in water contaminated with these microorganisms. The main objective of this study was to explore population-level and environmental determinants specifically associated with the presence of antimicrobial resistant (AMR) generic Escherichia coli isolated from recreational waters sampled from beaches located in southern Quebec, Canada. Water samples originated from the Quebec provincial beach surveillance program for the summers of 2004 and 2005. This study focused on three classes of determinants, namely: agricultural, population-level and beach characteristics for a total of 19 specific factors. The study was designed as a retrospective observational analysis and factors were assessed using logistic regression methods. From the multivariable analysis, the data suggested that the percentage of land used for spreading liquid manure was a significant factor associated with the presence of AMR E. coli (OR=27.73). Conceptually, broad factors potentially influencing the presence of AMR bacteria in water must be assessed specifically in addition to factors associated with general microbial contamination. Presence of AMR E. coli in recreational waters from beaches in southern Quebec may represent a risk for people engaging in water activities and this study provides preliminary evidence that agricultural practices, specifically spreading liquid manure in agricultural lands nearby beaches, may be linked to the contamination of these waters by AMR E. coli.  相似文献   

Parasitism by Cheyletiella parasitivorax; a case report of the infestation in a female dog and its litter     

SCHAFFER MH  BAKER NF  KENNEDY PC 《The Cornell veterinarian》1958,48(4):440-447

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The effect of divided dosage on the anthelmintic efficiency of phenothiazine in lambs     

DOUGLAS JR  BAKER NF  LONGHURST WM 《Journal of the American Veterinary Medical Association》1957,131(8):369-371

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红玫瑰李裂果防治试验     

曾明  尹克宁  蒋建国  李道高  谭孝才  李云龙  黄启光  余绍清 《西南园艺》1995,(3)

应用土施KC1、树盘覆盖、叶面喷施KH_2PO_4、CaNO_3以及GA涂果等处理,研究红玫瑰李的裂果率及果实糖酸含量的变化。结果表明:采前GA处理有降低裂粟的明显作用,裂果减少4%,尤其是5月中旬土壤覆盖结合GA处理,裂果率降低5.7~13.3%。K~ 、Ca~( )对减少裂果未表现出显著效果,但不同K~ 、Ca~( )施用浓度水平与果实总酸含量间有极显著的单一和交互作用,并建立如下的数学模型:y＝0.30 0.016X_1 0.04X_2 0.02X_1X_2—0.09X_1~2—0.037 X_2~2(P=0.0165,R~2=0.90534)。  相似文献   

Women in science: symposium and job mart     

Goldsmith NF 《Science (New York, N.Y.)》1970,168(3935):1124-1127

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AAHA senior care guidelines for dogs and cats     

Senior Care Guidelines Task Force  AAHA  Epstein M  Kuehn NF  Landsberg G  Lascelles BD  Marks SL  Schaedler JM  Tuzio H 《Journal of the American Animal Hospital Association》2005,41(2):81-91

This paper provides a working framework for enhancing the well-being of senior pet dogs and cats. Approaches to screening the medical status of senior pets are described in detail, with particular emphasis on establishing baseline data in healthy animals, the testing of clinically ill animals, and assessing senior pets prior to anesthesia and surgery. The management of pain and distress and the application of hospice and palliative care are addressed. Advice on ways to approach euthanasia and dealing with end-of-life issues is also provided.  相似文献   

Currents in la jolla and scripps submarine canyons     

Shepard FP  Marshall NF 《Science (New York, N.Y.)》1969,165(3889):177-178

Velocities up to 34 centimeters per second have been recorded near the floors of submarine canyons off La Jolla, California. Currents move alternately down- and upcanyon with variable periods. All 3- to 6-day measurements show net current transport downcanyon. Many of the downcanyon currents of higher velocity correlate with ebbing tides, as measured at the nearby pier. Other factors producing the currents probably include internal waves. Velocities are sufficient to transport large quantities of fine sand.  相似文献   

Darwinian evolution can follow only very few mutational paths to fitter proteins     

Weinreich DM  Delaney NF  Depristo MA  Hartl DL 《Science (New York, N.Y.)》2006,312(5770):111-114

Five point mutations in a particular beta-lactamase allele jointly increase bacterial resistance to a clinically important antibiotic by a factor of approximately 100,000. In principle, evolution to this high-resistance beta-lactamase might follow any of the 120 mutational trajectories linking these alleles. However, we demonstrate that 102 trajectories are inaccessible to Darwinian selection and that many of the remaining trajectories have negligible probabilities of realization, because four of these five mutations fail to increase drug resistance in some combinations. Pervasive biophysical pleiotropy within the beta-lactamase seems to be responsible, and because such pleiotropy appears to be a general property of missense mutations, we conclude that much protein evolution will be similarly constrained. This implies that the protein tape of life may be largely reproducible and even predictable.  相似文献