Spatial associations among density of cattle, abundance of wild canids, and seroprevalence to Neospora caninum in a population of beef calves   总被引：2，自引：0，他引：2  

Barling KS  Sherman M  Peterson MJ  Thompson JA  McNeill JW  Craig TM  Adams LG 《Journal of the American Veterinary Medical Association》2000,217(9):1361-1365

OBJECTIVE: To determine the epidemiologic plausibility of a sylvatic transmission cycle for Neospora caninum between wild canids and beef cattle. DESIGN: Spatial analysis study. ANIMALS: 1,009 weaned beef steers from 94 beef herds in Texas. PROCEDURE: Calves were grouped on the basis of seroprevalence for N caninum and ecologic region in Texas. The Morans I test was used to evaluate spatial interdependence for adjusted seroprevalence by ecologic region. Cattle density (Number of cattle/259 km2 [Number of cattle/100 mile2] of each ecologic region) and abundance indices for gray foxes and coyotes (Number of animals/161 spotlight-transect [census] km [Number of animals/100 census miles] of each ecologic region) were used as covariates in spatial regression models, with adjusted seroprevalence as the outcome variable. A geographic information system (GIS) that used similar covariate information for each county was used to validate spatial regression models. Results-Spatial interdependence was not detected for ecologic regions. Three spatial regression models were tested. Each model contained a variable for cattle density for the ecologic regions. Results for the 3 models revealed that seroprevalence was associated with cattle density and abundances of gray foxes, coyotes, or both. Abundances of gray foxes and coyotes were collinear. Results of a GIS-generated model validated these spatial models. CONCLUSIONS AND CLINICAL RELEVANCE: In Texas, beef cattle are at increased risk of exposure to N caninum as a result of the abundance of wild canids and the density of beef cattle. It is plausible that a sylvatic transmission cycle for neosporosis exists.  相似文献   

Amnesia: a function of the temporal relation of footshock to electroconvulsive shock   总被引：1，自引：0，他引：1  

A M Schneider  W Sherman 《Science (New York, N.Y.)》1968,159(811):219-221

When rats received a brief footshock upon stepping off an elevated platform, and an electroconvulsive shock 30 seconds or 6 hours afterward, amnesia was not observed 24 hours later. If a second footshock (noncontingent) was delivered 0.5 second before the electroconvulsive shock, amnesia was observed. The amnesia was temporary if conditioning was strong and permanent if conditioning was weak.  相似文献   

THE MEANING OF VITAMIN A     

Sherman HC 《Science (New York, N.Y.)》1928,68(1773):619-620

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Late pliocene faunal turnover in the turkana basin, kenya and ethiopia     

AK Behrensmeyer  NE Todd  R Potts  GE McBrinn 《Science (New York, N.Y.)》1997,278(5343):1589-1594

Analysis of a large sample of well-dated fossil mammals from localities in the Turkana Basin of Kenya and Ethiopia revealed sampling biases that affect patterns of faunal turnover during the late Pliocene. When these biases were accounted for, results indicated that 58 to 77 percent of the mammal species were replaced between 3.0 and 1.8 million years ago (Ma). Overall diversity increased from 3.0 to 2.0 Ma but then declined. No distinct turnover pulse is seen between 2.8 and 2.5 Ma; instead, the most significant period of faunal change began after 2.5 Ma and continued through 1.8 Ma.  相似文献   

GNAT-like strategy for polyketide chain initiation     

Gu L  Geders TW  Wang B  Gerwick WH  Håkansson K  Smith JL  Sherman DH 《Science (New York, N.Y.)》2007,318(5852):970-974

An unexpected biochemical strategy for chain initiation is described for the loading module of the polyketide synthase of curacin A, an anticancer lead derived from the marine cyanobacterium Lyngbya majuscula. A central GCN5-related N-acetyltransferase (GNAT) domain bears bifunctional decarboxylase/S-acetyltransferase activity, both unprecedented for the GNAT superfamily. A CurA loading tridomain, consisting of an adaptor domain, the GNAT domain, and an acyl carrier protein, was assessed biochemically, revealing that a domain showing homology to GNAT (GNAT(L)) catalyzes (i) decarboxylation of malonyl-coenzyme A (malonyl-CoA) to acetyl-CoA and (ii) direct S-acetyl transfer from acetyl-CoA to load an adjacent acyl carrier protein domain (ACP(L)). Moreover, the N-terminal adapter domain was shown to facilitate acetyl-group transfer. Crystal structures of GNAT(L) were solved at 1.95 angstroms (ligand-free form) and 2.75 angstroms (acyl-CoA complex), showing distinct substrate tunnels for acyl-CoA and holo-ACP(L) binding. Modeling and site-directed mutagenesis experiments demonstrated that histidine-389 and threonine-355, at the convergence of the CoA and ACP tunnels, participate in malonyl-CoA decarboxylation but not in acetyl-group transfer. Decarboxylation precedes acetyl-group transfer, leading to acetyl-ACP(L) as the key curacin A starter unit.  相似文献   

CRYSTALLINE AMYLASE     

Caldwell ML  Booher LE  Sherman HC 《Science (New York, N.Y.)》1931,74(1906):37-39

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Seasat synthetic aperture radar: ocean wave detection capabilities   总被引：1，自引：0，他引：1  

Gonzalez FI  Beal RC  Brown WE  Deleonibus PS  Sherman JW  Gower JF  Lichy D  Ross DB  Rufenach CL  Shuchman RA 《Science (New York, N.Y.)》1979,204(4400):1418-1421

A preliminary assessment has been made of the capability of the Seasat synthetic aperture radar to detect ocean waves. Comparison with surface and aircraft measurements from five passes of the satellite over the Gulf of Alaska indicates agreement to within about - 15 percent in wavelength and about +/- 25 degrees in wave direction. These results apply to waves 100 to 250 meters in length propagating in a direction predominantly across the satellite track, in sea states with significant wave height (H((1/3))) in a range of 2 to 3.5 meters.  相似文献   

Effects of liming on nutrient limitation of epilithic algae in an acid lake     

G. Winfield Fairchild  John W. Sherman 《Water, air, and soil pollution》1990,52(1-2):133-147

The processes of lake acidification and lake restoration frequently involve major changes in DIC and DIN, both of which may potentially limit algal growth. We evaluate nutrient limitation of benthic algal biomass and species abundances during summers 1987 and 1989, before and after the liming of Lake Earnest (NE Pennsylvania) in November 1988. Limestone addition caused immediate increases in pH from 4.7 to 7.2. Alkalinity was ?34 μeq L^?1 in summer 1987, but rose to 620 μeq L^?1 in summer 1989, whereas DIN declined from 10.7 μmol L^?1 to 1.1 μmol L^?1 The algae were sampled after 45 to 46 d from clay flower pot substrates diffusing combinations of N, P and C. Algal biomass was strongly C-limited in 1987, but NP-limited in 1989. Mougeotia sp., which comprised >99% of total algal biovolume prior to liming, declined to < 1% of the community on control substrates, while Oedogonium sp. increased to 43% of total biovolume in 1989. The stimulation of chlorophyll-a accrual with C-enrichment during 1987 was consistent with the later increase in chlorophyll-a on control substrates following liming. Species enhanced by the diffused nutrients, however, generally differed from those which dominated the natural community.  相似文献   

Field comparison of the interferon-gamma assay and the intradermal tuberculin test for the diagnosis of bovine tuberculosis   总被引：13，自引：0，他引：13  

PR WOOD  LA CORNER  JS ROTHEL  C. BALDOCK†  SL JONES†  DB COUSINS§  BS McCORMICK¶  BR FRANCIS§  J. CREEPER¶  NE TWEDDLE 《Australian veterinary journal》1991,68(9):286-290

An extensive field comparison of the gamma interferon (IFN-gamma) assay and the single intradermal tuberculin test for the diagnosis of bovine tuberculosis was conducted in Australia. The specificity of the IFN-gamma assay was determined by testing more than 6000 cattle from tuberculosis-free herds and varied from 96.2% to 98.1%, depending on the cut-off point chosen to define a positive reactor. For the sensitivity trial, cattle from herds being de-populated because of bovine tuberculosis were examined with both assays. The sensitivity of the IFN-gamma assay was shown to be significantly higher than the single intradermal tuberculin test and varied from 76.8% to 93.6% depending on the method of interpretation. A maximum overall sensitivity of 95.2% was obtained by testing with the IFN-gamma and the tuberculin test in parallel. The superior sensitivity of the IFN-gamma assay and the ability to adjust the sensitivity of the system depending on the task involved, will provide the Australian Tuberculosis Eradication Campaign with a valuable additional test to enable it to accomplish its goals.  相似文献   

Kartagener's syndrome in a Dachshund dog.     

Julie A Neil  Sherman O Canapp  Cristi R Cook  Jimmy C Lattimer 《Journal of the American Animal Hospital Association》2002,38(1):45-49

Kartagener's syndrome (KS) is a rare, congenital condition characterized by situs inversus, rhinosinusitis, and bronchiectasis. An underlying ciliary dysfunction (e.g., immotility or dyskinetic beating) produces most of the clinical signs seen in affected animals. This case report reviews the history, clinical signs, and diagnosis of KS in a male, long-haired dachshund. This is the first known report of KS, and thus primary ciliary dyskinesia, in this breed of dog.  相似文献