881 resultados para Defence Reactions


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As geopolitical competition between the United States and China intensifies, East Asian policy-makers are apprehensive about the Bush Administration's plans to develop ballistic missle defence (BMD). Missile defence threatens to undermine other fundamental assumptions aout nuclear weapons politics and arms control.

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Objective To determine the incidence and nature of adverse reactions of dogs and cats to tick antitoxin serum and to re-evaluate the role of atropine in the treatment of tick paralysis. Design A retrospective questionnaire of veterinarians. Procedure Questionnaires were posted to 320 veterinarians in tick-endemic regions of Australia. Questions referred to dogs and cats treated for tick paralysis over a period of three years: the number treated, treatment protocols and adverse systemic reactions to tick antitoxin serum. Ninety completed questionnaires were returned and responses analysed. Results Veterinarians reported that approximately 3% of dogs exhibited adverse reactions immediately following treatment with tick antitoxin serum, Eighteen percent of these reactions were described as anaphylaxis, with the remaining 82% attributed to the Bezold-Jarisch reflex. Six percent of cats treated with tick antitoxin serum reacted adversely and the majority of reactions (63%) were ascribed to the Bezold-Jarisch reflex. Atropine was used routinely by 10% of responding veterinarians in the treatment of dogs and cats with tick paralysis. A similar number of veterinarians used atropine only in selected cases. Most veterinarians (76%) reported that they never used atropine in the treatment of tick paralysis in either dogs or cats. Within the survey population, premedication with atropine reduced the number of Bezold-Jarisch reactions following tick antitoxin administration approximately five-fold in dogs and four-fold in cats. Conclusions Data from this pilot survey indicate that more cats than dogs have adverse systemic reactions to tick antitoxin serum and that the majority of these reactions in both dogs and cats could be related to the Bezold-Jarisch reflex. The number of reactions to tick antitoxin serum in dogs and cats could be significantly reduced by the routine use of atropine prior to administration of tick antitoxin serum.

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Some materials exhibit a combustion event during mechanical alloying, which results in the rapid transformation of reactants into products, while others show a slow transformation of reactants into products, In this paper, the continuous W + C --> WC reaction is compared to the Ti + C --> TiC combustion reaction. Rietveld refinement of X-ray diffraction patterns is used to show that these particular reactions proceed through different pathways, determined by crystallographic factors of the reactants. When a crystallographic relationship exists between the reactants and the products, such as that between W and WC, the product forms slowly over a period of time. In contrast, insertion of C into the Ti structure is associated with atomic rearrangements within the crowded lattice planes and the subsequent catastrophic failure of the reactant lattices results in combustion to form TiC. (C) 2001 Academic Press.

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The formation of molecular complexes (prereactive intermediates) between C3O2 and amines (ammonia, dimethylamine, trimethylamine, and 4-(dimethylamino)pyridine) as well as the subsequent transformation of the complexes into C3O2-amine zwitterions in cryogenic matrixes (ca. 40 K) has been observed. In the case of dimethylamine, the formation of tetramethylmalonamide has also been documented. Calculations using density functional theory (B3LYP/6-31G(2d, p)) are used to assign all above species and are in excellent agreement with the IR spectra.

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Piston-cylinder experiments in the granite system demonstrate that a variety of isotopically distinct melts can arise from progressive melting of a single source. The relation between the isotopic composition of Sr and the stoichiometry of the observed melting reactions suggests that isotopic signatures of anatectic magmas can be used to infer melting reactions in natural systems. Our results also indicate that distinct episodes of dehydration and fluid-fluxed melting of a single, metapelitic source region may have contributed to the bimodal geochemistry of crustally derived leucogranites of the Himalayan orogen.

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On return from duty in North Solomons Province (including Bougainville Island), Papua New Guinea, 586 Australian Defence Force personnel received either primaquine (14-d) or tafenoquine (3-d) post-exposure malaria prophylaxis. Within 12 months, 6 of the 214 volunteers receiving primaquine and 7 of 378 receiving tafenoquine had developed vivax malaria. Overall, volunteers preferred the shorter course of tafenoquine.

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Male and female consumers place different emphasis on elements of the service recovery process. Perceptions were influenced by gender of the service provider and by a match of customer and service provider gender. The study, an experimental design with 712 respondents, found that when service providers, irrespective of gender, display concern and give customers voice and a sizable compensation, both men and women reported more positive attitudes compared with when this was not so. Combinations of high voice with high outcome and high voice with high concern were especially important in positively influencing perceptions of effort, regardless of gender. However, the authors also found that there were significant differences between male and female respondents regarding their perceptions of how service recovery should be handled. Women want their views heard during service recovery attempts and to be allowed to provide input. Men, in contrast, do not view voice as important.

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Anthracnose and crown rot, caused by Colletotrichum trifolii, are serious diseases of lucerne (Medicago saliva L.) in humid regions of the world. A race survey was conducted by inoculating individual lucerne clones (genotypes) with C. trifolii isolates collected from a range of Medicago hosts, locations, and years in south-eastern Queensland. This survey revealed for the first time in Australia the presence of race 2 (virulence on anthracnose resistance gene An I) and the first world report of race 4 (virulence on An(2)). A collection of North American race I and race 2 C. trifolii isolates, when inoculated onto the Australian differential clones, gave responses that were in agreement with their North American reactions. A RAPD analysis was conducted on 9 Australian C. trifolii isolates including races 1, 2, and 4; two C. destructivum and one C. gloeosporioides isolate were included as known outliers. For the C. trifolii isolates, 94.6% similarity was found regardless of host origin or race, compared with 2.2% similarity between this group and the C. gloeosporioides and C. destructivum isolates, confirming that the new races belong to C. trifolii. Currently, it is hypothesised that only plants carrying genes An, and An2 are resistant to the 3 races. Of 22 cultivars screened against the 3 races, only UQL-1, Hallmark, and Pioneer 54Q53 had >30% of plants resistant to the 3 races in separate screenings. The research highlights the need to find new sources of resistance to C. trifolii in lucerne.

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Background: In the presence of dNTPs, intact HIV-1 virions are capable of reverse transcribing at least part of their genome, a process known as natural endogenous reverse transcription (NERT). PCR analysis of virion DNA produced by NERT revealed that the first strand transfer reaction (1stST) was inefficient in intact virions, with minus strand (-) strong stop DNA (ssDNA) copy numbers up to 200 times higher than post-1stST products measured using primers in U3 and U5. This was in marked contrast to the efficiency of 1stST observed in single-round cell infection assays, in which (-) ssDNA and U3-U5 copy numbers were indistinguishable. Objectives: To investigate the reasons for the discrepancy in first strand transfer efficiency between intact cell-free virus and the infection process. Study design: Alterations of both NERT reactions and the conditions of cell infection were used to test whether uncoating and/or entry play a role in the discrepancy in first strand transfer efficiency. Results and Conclusions: The difference in 1stST efficiency could not be attributed simply to viral uncoating, since addition of very low concentrations of detergent to NERT reactions removed the viral envelope without disrupting the reverse transcription complex, and these conditions resulted in no improvement in 1stST efficiency. Virus pseudotyped with surface glycoproteins from either vesicular stomatitis virus or amphotrophic murine leukaemia virus also showed low levels of 1stST in low detergent NERT assays and equivalent levels of (-) ssDNA and 1stST in single-round infections of cells, demonstrating that the gp120-mediated infection process did not select for virions capable of carrying out 1stST. These data indicate that a post-entry event or factor may be involved in efficient HIV-1 reverse transcription in vivo. (C) 2002 Elsevier Science B.V. All rights reserved.

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Sco proteins are found in mitochondria and in a variety of oxidase positive bacteria. Although Sco is required for the formation of the Cu-A centre in a cytochrome oxidase of the aa(3) type, it was observed that oxidases with a Cu-A centre are not present in many bacteria that contain a Sco homologue. Two bacteria of this type are the pathogens Neisseria meningitidis and Neisseria gonorrhoeae. The sco genes of N. gonorrhoeae strain 1291 and N. meningitidis strain MC58 were cloned, inactivated by inserting a kanamycin resistance cassette and used to make knockout mutants by allelic exchange. Both N. gonorrhoeae and N. meningitidis sco mutants were highly sensitive to oxidative killing by paraquat, indicating that Sco is involved in protection against oxidative stress in these bacteria. (C) 2003 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.

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The kinetics of chain reactions of octanedithiol with styrene, thermally initiated with TX29B50 (a 50:50 wt% solution of TX29 diperoxy initiator in a phthalate plasticizer), have been studied over a range of initiator concentrations, a range of mixture formulations and a range of temperatures. This system has been investigated as a model system for the reactions of polyfunctional thiols with divinyl benzene. The reactions have been shown to follow first-order kinetics for both the thiol and the ene species and to be characterized by a dependence on the initiator concentration to the power of one half. The kinetic rate parameters have been shown to adhere to Arrhenius behaviour. A kinetic model for the chain reactions for this system has been proposed. (C) 2003 Society of Chemical Industry.

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In sport there is a great need to obtain as much information as possible about the factors which affect the dynamics of play. This study uses sequential analysis and temporal patterns (T-patterns)to examine the evolution of defence (against an equal number of attackers)as used by the Spanish handball team at the Beijing 2008 Olympic Games. The aim is to help handball coaches (during their training and gathering of professional experience)to understand the importance of the structure of defensive systems. This can be achieved through observational processes that reveal the evolution and adaptation of these defensive systems according to different variables: the match score, the response of the opposing team and progress through the tournament.