Dynamical Instabilities and the Formation of Extrasolar Planetary Systems     

FA Rasio  EB Ford 《Science (New York, N.Y.)》1996,274(5289):954-956

The existence of a dominant massive planet, Jupiter, in our solar system, although perhaps essential for long-term dynamical stability and the development of life, may not be typical of planetary systems that form around other stars. In a system containing two Jupiter-like planets, the possibility exists that a dynamical instability will develop. Computer simulations suggest that in many cases this instability leads to the ejection of one planet while the other is left in a smaller, eccentric orbit. In extreme cases, the eccentric orbit has a small enough periastron distance that it may circularize at an orbital period as short as a few days through tidal dissipation. This may explain the recently detected Jupiter-mass planets in very tight circular orbits and wider eccentric orbits around nearby stars.  相似文献   

Assessment of organoleptic postmortem inspection techniques for bovine offal     

FA UZAL  SJ MORE  B. DOBRENOV  WR KELLY 《Australian veterinary journal》2002,80(1):70-74

Objective To evaluate organoleptic postmortem inspection techniques for bovine livers and kidneys.
Study design At Australian export abattoirs, bovine liver and kidneys are assessed and graded by qualified meat inspectors during normal operations. Over a 12-month period at a large abattoir in eastern Australia during 1997 and 1998, a sample of these organs was reassessed independently using a range of pathological and microbiological methods. Agreement between routine inspection and independent assessment was evaluated using methods of inter-rater agreement.
Results A total of 944 livers and 1374 kidneys were included in the study. All of these organs had been classified during routine inspection. The authors examined 363 livers and 329 kidneys both grossly and histologically, including 36 livers and 14 kidneys that were also subjected to microbiological examination. All other organs were only examined grossly. There was only a moderate level of agreement between the routine and independent assessment methods. For livers, the percentage agreement was 80.2%, McNemar's test of symmetry 55.2 (3 degrees of freedom, P < 0.001) and kappa 0.63. For kidneys, the percentage agreement was 67.8%, McNemar's test of symmetry 9.9 (1df, P = 0.002) and kappa 0.35.
Conclusions The results reinforce concerns from a number of authors about organoleptic postmortem inspection. Risk assessment methodologies offer the opportunity to modify inspection techniques in a manner that is most relevant to current public health concerns.  相似文献   

Unilateral Nephrectomy in a Juvenile Llama     

LINDA VAN HOOGMOED DVM  Diplomate ACVS    JACK R. SNYDER DVM  PHD  Diplomate ACVS    GREGORY ROBERTS DVM  MS  Diplomate ACVR  FA YE A. HARMON 《Veterinary surgery : VS》1997,26(6):497-501

Objective —The purpose of this study was to decribe the clinical presentation, diagnostic evaluation, and surgical management of a llama with an ectopic ureter.
Animals or Sample Population —Nine-month-old female llama.
Results —The diagnostic evaluation included the use of computed tomography and an excretory ureterogram to confirm and identify the location of the ectopic ureter. Surgical management involved a unilateral nephrectomy.
Conclusions and Clinical Relevance —Computed tomography is a valuable asset to diagnose the presence and terminal location of an ectopic ureter in llamas, and nephrectomy appears to be a viable procedure to resolve the subsequent urinary incontinence.  相似文献   

Use of whey proteins for supplementing tortilla     

V Racotta  H Bourges  A Navarrete  J Zuckermann 《Journal of agricultural and food chemistry》1979,27(4):668-672

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猪繁殖和呼吸综合征的研究进展     

FA Osorio  唐文渊 《国外畜牧学(猪与禽)》2003,23(2):55-56

从近二年来已经发表或即将发表的文献来看,猪繁殖和呼吸综合征的研究已经取得了一些极为显著的进展。  相似文献   

Identification of key immune mediators regulating T helper 1 responses in swine     

Dawson HD  Royaee AR  Nishi S  Kuhar D  Schnitzlein WM  Zuckermann F  Urban J  Lunney JK 《Veterinary immunology and immunopathology》2004,100(1-2):105-111

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Cytokines and synthetic double-stranded RNA augment the T helper 1 immune response of swine to porcine reproductive and respiratory syndrome virus   总被引：3，自引：0，他引：3  

Meier WA  Husmann RJ  Schnitzlein WM  Osorio FA  Lunney JK  Zuckermann FA 《Veterinary immunology and immunopathology》2004,102(3):299-314

Immunization of pigs with a modified live porcine reproductive and respiratory syndrome virus (PRRSV) vaccine initially elicits a weak interferon (IFN)-gamma response. To improve the immune response, an adjuvant consisting of plasmid encoding either porcine interleukin (IL)-12 or IFN-alpha was co-administered during vaccination. In the presence of either adjuvant, at least a three-fold increase in the primary virus-specific IFN-gamma response was observed. While this enhancement was only transient (1 week) when the IL-12 expressing plasmid was used, the effect was not only still apparent at 6 weeks after vaccination in the presence of the IFN-alpha expressing plasmid but even after challenge with a virulent genetically divergent PRRSV. In contrast, no effect of either adjuvant on the production of anti-virus antibodies was noticed throughout the study. Despite the apparent augmentation of a T helper (Th) 1 type response by the inclusion of IFN-alpha or IL-12 during vaccination, this modulation did not necessarily correlate with a reduction in viremia. Since a similar increase in the degree of the IFN-gamma response to the PRRSV vaccine could be achieved by substituting polyinosinic-polycytidylic acid in lieu of either cytokine, exposure to PRRSV in the presence of a variety of Th 1 polarizing molecules can positively influence the development of the cell-mediated immune response of swine to this pathogen. Conceivably, such intervention could be applied to improve the formulation of anti-PRRSV vaccines.  相似文献   

Deciphering the involvement of innate immune factors in the development of the host response to PRRSV vaccination   总被引：10，自引：0，他引：10  

Royaee AR  Husmann RJ  Dawson HD  Calzada-Nova G  Schnitzlein WM  Zuckermann FA  Lunney JK 《Veterinary immunology and immunopathology》2004,102(3):199-216

The natural response of pigs to porcine reproductive and respiratory syndrome virus (PRRSV) infections and vaccinations needs to be altered so that better protection is afforded against both homologous and heterologous challenges by this pathogen. To address this problem, real-time gene expression assays were coupled with cytokine Elispot and protein analyses to assess the nature of the anti-PRRSV response of pigs immunized with modified live virus (MLV) vaccine. Although T helper 1 (Th1) immunity was elicited in all vaccinated animals, as evidenced by the genesis of PRRSV-specific interferon-gamma secreting cells (IFNG SC), the overall extent of the memory response was variable and generally weak. Peripheral blood mononuclear cells (PBMC) isolated from these pigs responded to PRRSV exposure with a limited increase in their expression of the Th1 immune markers, IFNG, tumor necrosis factor-alpha and interleukin-15 (IL15), and a reduction in the quantity of mRNAs encoding the innate and inflammatory proteins, IL1B, IL8 and IFNA. Efforts to enhance Th1 immunity, by utilizing an expression plasmid encoding porcine IFNA (pINA) as an adjuvant, resulted in a temporary increase in the frequency of PRRSV-specific IFNG SC but only minor changes overall in the expression of Th1 associated cytokine or innate immune marker mRNA by virus-stimulated PBMC. Administration of pINA, however, did correlate with decreased IL1B secretion by cultured, unstimulated PBMC but had no effect on their ability to release IFNG. Thus, while exogenous addition of IFNA during PRRSV vaccination has an impact on the development of a Th1 immune response, other alterations will be required for substantial boosting of virus-specific protection.  相似文献   

Evaluation of contact exposure as a method for acclimatizing growing pigs to porcine reproductive and respiratory syndrome virus   总被引：1，自引：0，他引：1  

Vashisht K  Erlandson KR  Firkins LD  Zuckermann FA  Goldberg TL 《Journal of the American Veterinary Medical Association》2008,232(10):1530-1535

OBJECTIVE: To determine whether 6.5-week-old gilts that have not previously been exposed to porcine reproductive and respiratory syndrome (PRRS) virus can be acclimatized to an endemic strain of the virus by commingling with age-matched gilts inoculated with the endemic PRRS virus strain and whether 10.5-week-old gilts can be acclimatized by commingling with age-matched inoculated or contact-exposed animals. DESIGN: Randomized controlled longitudinal study. ANIMALS: 80 gilts seronegative for PRRS on a farm in the Midwestern United States with a history of PRRS. PROCEDURES: 20 gilts were inoculated with the endemic PRRS virus strain at 6.5 weeks of age (group 1) and were commingled with 20 gilts that were not inoculated (group 2). Four weeks later, the remaining 40 gilts (group 3) were commingled with gilts in groups 1 and 2. Presence of viral RNA in the tonsils, seroconversion rate, serum neutralizing antibody titers, interferon-gamma-mediated cellular immunity, and reproductive outcomes were analyzed. RESULTS: Acclimatization of PRRS virus-na?ve pigs was achieved by means of contact exposure at both 6.5 and 10.5 weeks of age. No differences were observed among the 3 groups with respect to development of anti-PRRS virus-specific immune responses or reproductive outcomes. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that contact exposure of 6.5- to 10.5-week-old pigs that had not previously been exposed to PRRS virus to pigs inoculated with endemic PRRS virus may be an efficient acclimatization strategy for controlling outbreaks on commercial farms on which PRRS is endemic.  相似文献   

Determination of the specificity of CD45 and CD45R monoclonal antibodies through the use of transfected hamster cells producing individual porcine CD45 isoforms     

William M. Schnitzlein  Federico A. Zuckermann 《Veterinary immunology and immunopathology》1998,60(3-4):389-401

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