Issues in biosecurity and biosafety     

Cook-Deegan RM  Berkelman R  Davidson EM  Finder S  Heitman E  Kelley MC  King NM  Moseley R  Thomas JC  Tilden SJ  Vangsnes NM 《Science (New York, N.Y.)》2005,308(5730):1867-1868

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The galilean satellites and jupiter: voyager 2 imaging science results     

Smith BA  Soderblom LA  Beebe R  Boyce J  Briggs G  Carr M  Collins SA  Cook AF  Danielson GE  Davies ME  Hunt GE  Ingersoll A  Johnson TV  Masursky H  McCauley J  Morrison D  Owen T  Sagan C  Shoemaker EM  Strom R  Suomi VE  Veverka J 《Science (New York, N.Y.)》1979,206(4421):927-950

Voyager 2, during its encounter with the Jupiter system, provided images that both complement and supplement in important ways the Voyager 1 images. While many changes have been observed in Jupiter's visual appearance, few, yet significant, changes have been detected in the principal atmospheric currents. Jupiter's ring system is strongly forward scattering at visual wavelengths and consists of a narrow annulus of highest particle density, within which is a broader region in which the density is lower. On Io, changes are observed in eruptive activity, plume structure, and surface albedo patterns. Europa's surface retains little or no record of intense meteorite bombardment, but does reveal a complex and, as yet, little-understood system of overlapping bright and dark linear features. Ganymede is found to have at least one unit of heavily cratered terrain on a surface that otherwise suggests widespread tectonism. Except for two large ringed basins, Callisto's entire surface is heavily cratered.  相似文献   

Surface ices and the atmospheric composition of pluto     

Owen TC  Roush TL  Cruikshank DP  Elliot JL  Young LA  de Bergh C  Schmitt B  Geballe TR  Brown RH  Bartholomew MJ 《Science (New York, N.Y.)》1993,261(5122):745-748

Observations of the 1.4- to 2.4-micrometer spectrum of Pluto reveal absorptions of carbon monoxide and nitrogen ices and confirm the presence of solid methane. Frozen nitrogen is more abundant than the other two ices by a factor of about 50; gaseous nitrogen must therefore be the major atmospheric constituent. The absence of carbon dioxide absorptions is one of several differences between the spectra of Pluto and Triton in this region. Both worlds carry information about the composition of the solar nebula and the processes by which icy planetesimals formed.  相似文献   

Leave regulation to the FDA     

Hughes OC 《Science (New York, N.Y.)》2008,321(5888):490

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Retraction     

Witte ON  Kabarowski JH  Xu Y  Le LQ  Zhu K 《Science (New York, N.Y.)》2005,307(5707):206

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Evaluation of spectrophotometric and HPLC methods for shikimic acid determination in plants: models in glyphosate-resistant and -susceptible crops     

Zelaya IA  Anderson JA  Owen MD  Landes RD 《Journal of agricultural and food chemistry》2011,59(6):2202-2212

Endogenous shikimic acid determinations are routinely used to assess the efficacy of glyphosate in plants. Numerous analytical methods exist in the public domain for the detection of shikimic acid, yet the most commonly cited comprise spectrophotometric and high-pressure liquid chromatography (HPLC) methods. This paper compares an HPLC and two spectrophotometric methods (Spec 1 and Spec 2) and assesses the effectiveness in the detection of shikimic acid in the tissues of glyphosate-treated plants. Furthermore, the study evaluates the versatility of two acid-based shikimic acid extraction methods and assesses the longevity of plant extract samples under different storage conditions. Finally, Spec 1 and Spec 2 are further characterized with respect to (1) the capacity to discern between shikimic acid and chemically related alicyclic hydroxy acids, (2) the stability of the chromophore (t1/2), (3) the detection limits, and (4) the cost and simplicity of undertaking the analytical procedure. Overall, spectrophotometric methods were more cost-effective and simpler to execute yet provided a narrower detection limit compared to HPLC. All three methods were specific to shikimic acid and detected the compound in the tissues of glyphosate-susceptible crops, increasing exponentially in concentration within 24 h of glyphosate application and plateauing at approximately 72 h. Spec 1 estimated more shikimic acid in identical plant extract samples compared to Spec 2 and, likewise, HPLC detection was more effective than spectrophotometric determinations. Given the unprecedented global adoption of glyphosate-resistant crops and concomitant use of glyphosate, an effective and accurate assessment of glyphosate efficacy is important. Endogenous shikimic acid determinations are instrumental in corroborating the efficacy of glyphosate and therefore have numerous applications in herbicide research and related areas of science as well as resolving many commercial issues as a consequence of glyphosate utilization.  相似文献   

Feline cholangitis: a necropsy study of 44 cats (1986-2008)     

Callahan Clark JE  Haddad JL  Brown DC  Morgan MJ  Van Winkle TJ  Rondeau MP 《Journal of Feline Medicine and Surgery》2011,13(8):570-576

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Prevalence of echocardiographic evidence of cardiac disease in apparently healthy cats with murmurs     

Nakamura RK  Rishniw M  King MK  Sammarco CD 《Journal of Feline Medicine and Surgery》2011,13(4):266-271

The objective of this prospective study was to determine the prevalence of echocardiographic evidence of heart disease in apparently healthy cats with heart murmurs. Thirty-two privately owned domestic cats were examined. All cats were considered healthy on the basis of history and physical examination, except for the finding of a heart murmur on auscultation. Cats on any medications (besides regular flea, tick and heartworm preventative) or that were pregnant or lactating were excluded from this study. The prevalence of echocardiographic evidence of heart disease in this population of cats was 53%. Therefore, identification of a heart murmur on routine physical examination in apparently healthy cats warrants further investigation.  相似文献   

Use of a self-expanding metallic stent for the treatment of a urethral stricture in a young cat     

Hadar EN  Morgan MJ  Morgan OD 《Journal of Feline Medicine and Surgery》2011,13(8):597-601

A 4-month-old intact male domestic shorthair cat was evaluated for urinary outflow obstruction after several weeks of medical management for traumatic urethral rupture. Positive-contrast retrograde urethrography and anterograde cystoscopy performed 4 weeks after the initial urethral injury confirmed a stricture approximately 1cm distal to the bladder trigone at the site of the initial urethral tear. A self-expanding metallic urethral stent (SEMS) was placed under fluoroscopic guidance to relieve the urethral stricture and re-establish luminal patency. After stent placement, the cat was able to void urine normally with minimal urinary incontinence noted. This resolved several months post-stent placement. No known clinical complications persisted other than mild intermittent hematuria.  相似文献   

Benchmark study on glyphosate-resistant crop systems in the United States. Part 2: Perspectives     

Owen MD  Young BG  Shaw DR  Wilson RG  Jordan DL  Dixon PM  Weller SC 《Pest management science》2011,67(7):747-757

A six-state, 5 year field project was initiated in 2006 to study weed management methods that foster the sustainability of genetically engineered (GE) glyphosate-resistant (GR) crop systems. The benchmark study field-scale experiments were initiated following a survey, conducted in the winter of 2005-2006, of farmer opinions on weed management practices and their views on GR weeds and management tactics. The main survey findings supported the premise that growers were generally less aware of the significance of evolved herbicide resistance and did not have a high recognition of the strong selection pressure from herbicides on the evolution of herbicide-resistant (HR) weeds. The results of the benchmark study survey indicated that there are educational challenges to implement sustainable GR-based crop systems and helped guide the development of the field-scale benchmark study. Paramount is the need to develop consistent and clearly articulated science-based management recommendations that enable farmers to reduce the potential for HR weeds. This paper provides background perspectives about the use of GR crops, the impact of these crops and an overview of different opinions about the use of GR crops on agriculture and society, as well as defining how the benchmark study will address these issues.  相似文献