Sulfate aerosols and polar stratospheric cloud formation     

Tolbert MA 《Science (New York, N.Y.)》1994,264(5158):527-528

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What Is Your Diagnosis?     

Walton RM  Thrall MA  Wheeler S 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》1994,23(4):117-118

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A note on the use of inbreeding in progeny test schemes     

Toro MA 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》1993,110(1-6):234-240

SUMMARY: In this note some theoretical and simulated results are presented comparing the selection response in a progeny test scheme that utilizes inbred offspring for testing, with respect to a standard progeny test. The theory indicates a substantial increase in selection response, although the advantage decreases as the number of dams mated to a sire and the number of offspring per dam increases. The advantage is at a maximum when the variation of the trait is due to segregation of recessive alleles at low frequencies unfavourable to the direction of selection. Computer simulation confirmed the advantage of the method. ZUSAMMENFASSUNG: Verwendung von Inzuchttieren bei der Nachkommenschaftsprüfung Hier wurden theoretische und simulierte Selektionserfolge konventioneller Nachkommenschaftsprüfung mit Prüfung von Inzuchtnachkommen verglichen. Theoretisch zeigt sich ein erheblicher Vorteil der letzteren, wenn dieser auch mit steigende Zahl von Partnern und deren Nachkommen abnimmt und nach null tendiert. Der Vorteil der Nachkommenschaftsprüfung ingezüchteter Nachkommen ist am h?chsten, wenn seltene ungünstige rezessive Gene eine Rolle spielen. Rechner-Simulation best?tigt den Vorteil dieser Vorgangsweise.  相似文献   

Alberta. Infectious laryngotracheitis in commercial broiler chickens   总被引：1，自引：0，他引：1       下载免费PDF全文

Vanderkop MA 《The Canadian veterinary journal. La revue veterinaire canadienne》1993,34(3):185

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Factors associated with past and potential future use of veterinarians by Ontario trout farmers          下载免费PDF全文

Thorburn MA 《The Canadian veterinary journal. La revue veterinaire canadienne》1993,34(10):611-618

This study investigated whether certain variables were associated with Ontario trout farmers' use of the Fish Pathology Laboratory (FPL), Ontario Veterinary College, or their willingness to pay for private veterinary services. Sixty-two farmers, representing 91% of Ontario's 1990 farmed trout production, were personally interviewed. Logistic regression was used to compare the 26 farmers who had submitted fish to the FPL during the previous two years to those who had not. Submitters tended to have been fish farming for fewer years, and to produce more fish, use more workers, treat prophylactically less frequently, keep records of drug treatments, and not disinfect holding units (p<0.05). Most farmers stated they would occasionally hire a private veterinarian. Only 13 farmers anticipated hiring one more than once per year. Polychotomous regression showed that farmers who purchased, instead of hatched, their seed stock, kept records, treated therapeutically often, and used several workers would hire private veterinarians more frequently (p<0.05). Strategies are discussed by which the veterinary profession might better understand and meet the needs of the aquaculture industry.  相似文献   

Self-Assembled Metal Colloid Monolayers: An Approach to SERS Substrates     

Freeman RG  Grabar KC  Allison KJ  Bright RM  Davis JA  Guthrie AP  Hommer MB  Jackson MA  Smith PC  Walter DG  Natan MJ 《Science (New York, N.Y.)》1995,267(5204):1629-1632

The self-assembly of monodisperse gold and silver colloid particles into monolayers on polymer-coated substrates yields macroscopic surfaces that are highly active for surface-enhanced Raman scattering (SERS). Particles are bound to the substrate through multiple bonds between the colloidal metal and functional groups on the polymer such as cyanide (CN), amine (NH(2)), and thiol (SH). Surface evolution, which can be followed in real time by ultraviolet-visible spectroscopy and SERS, can be controlled to yield high reproducibility on both the nanometer and the centimeter scales. On conducting substrates, colloid monolayers are electrochemically addressable and behave like a collection of closely spaced microelectrodes. These favorable properties and the ease of monolayer construction suggest a widespread use for metal colloid-based substrates.  相似文献   

Bites and stings     

Mayse MA 《Science (New York, N.Y.)》1981,214(4520):494

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不同储藏条件下甜高粱茎秆汁液糖度变化规律研究     

张华文  杨延兵  王海莲  秦岭  管延安 《华北农学报》2011,(z1):56-59

利用锤度不同的6个高粱品种,研究了离心和储藏温度对高粱茎秆汁液锤度的影响.结果表明:榨汁后离心与未离心的品种锤度差异不显著.在常温下放置6d后,未离心的品种糖度下降到最低,而离心后的品种在常温下放置到9d糖度下降到最低.在常温,4℃和-20℃的储藏条件下放置30 d后,与最初的糖度相比,每种储藏条件下的品种糖锤度都有一...  相似文献   

Lignans from Seeds of Herpetospermum caudigerum Wall.Protect Against Alcoholic Liver Injury via TGF-β/Smads Pathway in Rats     

Qi MA  Jian GU  Puyang GONG  Maojia LI  Ni MA  Yanxi LI 《Medicinal Plant》2020,(2):54-57

[Objectives]This study aimed to investigate the effects of lignans from seeds of Herpetospermum caudigerum Wall.(SHC)on expression of TGF-β/Smads in liver tissue of hepatic alcohol-injuried rats,and to explore its protective mechanism.[Methods]A total of 60 SD rats were randomly divided into six groups.The rats in all the groups except those in the normal group were given with white spirit by gavage for 8 weeks to establish alcoholic liver injury models.After rat models were established successfully,they were administered intragastrically with 400,200 and 100 mg/kg of lignans,respectively.The rats in the normal group were administered intragastrically with 50 mg/kg of silymarin.The administration lasted for 8 weeks,once a day.The changes in the general state,liver tissue pathology and collagen deposition of the rats were observed.The expression of TGF-β,TGF-β1 receptor 1(TβR-I),TGF-β1 receptor 2(TβR-II),Smad2/p-Smad2 and Smad3/p-Smad3 in the hepatic tissue was detected.[Results]The expression levels of TGF-β1,Smad2,p-Smad2,and p-Smad3 significantly declined,and the expression levels of TβR-I,TβR-II and Smad3 did not change significantly in the liver tissue of rats in the lignans groups and the expression levels of TGF-β,Smad2,and p-Smad3 significantly declined.Meanwhile,the expression levels of TβR-I,TβR-II,p-Smad2 and Smad3 did not change significantly in the silymarin group.[Conclusions]The lignans from SHC have significant intervention effects on alcoholic livery injury.The mechanism may be related to the inhibition of hepatic stellate cell(HSC)activation,TGF-βsecretion and p-Smad2,p-Smad3 expression in the signaling pathway.  相似文献   

Advances in Study of Natural Antibacterial Medicines     

Ainuan LI  Xiao YANG  Zihao MA  Rui ZENG 《Medicinal Plant》2020,(2):1-4

This paper introduce the advances in study of antibacterial effects of natural medicines in the past ten years.The antibacterial components of natural medicines mainly include flavonoids,terpenoids,alkaloids,lignans,phenols,etc..This paper is intended to provide data reference for the research and development of new natural antibacterial medicines.  相似文献