504 research outputs found

    A Zoopolean look at animal research ethics

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    I will discuss how animal laboratory research can be ethically analyzed using Donaldson and Kymlicka’s political theory of animal rights. To accomplish this, I will not presuppose their strong animal rights framework. Donaldson and Kymlicka’s approach revolves around some basic human-animal relationships, reflecting the relational turn in applied ethics writ large. However, they do not discuss laboratory animal research in any detail, and so an extension to that domain of animal use is in order. Donaldson and Kymlicka’s emphasis on human-animal relationships is useful for reminding ourselves that in laboratories various staff or personnel can develop bonds with captive animals that make it difficult to follow certain protocols as well as create a deep and lasting negative impression. Though, when suitably modified, Donaldson and Kymlicka’s political theory can apply to animal research ethics, it can only do so though if we ask more from all members of our society

    La vulnĂ©rabilitĂ© stratĂ©gique des minĂ©raux : les relations triangulaires entre la RĂ©publique fĂ©dĂ©rale allemande, l’Afrique du Sud et l’Union soviĂ©tique.

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    Resource diplomacy has emerged as a key element in international relations. The controversy over the use of the grain embargo and persistent concern about the Middle East has allowed food and oil to continue to gain a great deal of attention as weapons of resource diplomacy. Other raw materials, nevertheless, also lend themselves to analysis of this sort. Strategic minerals, in particular, have been increasingly looked at as means of influence in both North/South and the East I West contexts. This study hopes to contribute to this growing body of literature by examining the significance (and merger) of the North/South and East I West contexts in regard to strategic minerals with particular reference to the Federal Republic of Germany. The paper examines the triangular relationship in strategic minerals between the FRG, Southern Africa and the Soviet Union. A number of scenarios have been put forward pertaining to a Soviet threat to Western mineral imports from Southern Africa. The most plausible of these scenarios appears to be that rather than the Soviets initiating action in Africa they respond to events in order to undermine confidence in the West. Such a scenario has serious implications for the FRG. Still, our tentative findings are that dire forecasts about a Soviet stranglehold on the FRG in terms of minerals are overplayed. It is suggested that coping mechanisms do exist for the FRG's supplies of raw materials

    Investigating the relationship between HIV testing and risk behaviour in Britain: National Survey of Sexual Attitudes and Lifestyles 2000.

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    OBJECTIVES: To estimate the prevalence of, and identify factors associated with, HIV testing in Britain. DESIGN: A large, stratified probability sample survey of sexual attitudes and lifestyles. METHODS: A total of 12,110 16-44 year olds completed a computer-assisted face-to-face interview and self-interview. Self-reports of HIV testing, i.e. the timing, reasons for and location of testing, were included. RESULTS: A total of 32.4% of men and 31.7% of women reported ever having had an HIV test, the majority of whom were tested through blood donation. When screening for blood donation and pregnancy were excluded, 9.0% of men and 4.6% of women had had a voluntary confidential HIV test (VCT) in the past 5 years. However, one third of injecting drug users and men who have sex with men had a VCT in the past 5 years. VCT in the past 5 years was significantly associated with age, residence, ethnicity, self-perceived HIV risk, reporting greater numbers of sexual partners, new sexual partners from abroad, previous sexually transmitted infection diagnosis, and injecting non-prescribed drugs for men and women, and same-sex partners (men only). Whereas sexually transmitted disease clinics were important sites for VCT, general practice accounted for almost a quarter of VCT. CONCLUSION: HIV testing is relatively common in Britain; however, it remains largely associated with population-based blood donation and antenatal screening programmes. In contrast, VCT remains highly associated with high-risk (sexual or drug-injecting) behaviours or population sub-groups at high risk. Strategies to reduce undiagnosed prevalent HIV infection will require further normalization and wider uptake of HIV testing

    Roles of cytoskeletal proteins in the predatory life cycle of Bdellovibrio bacteriovorus

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    Bdellovibrio bacteriovorus are small, predatory bacteria that grow within the periplasmic space of a host bacterium. Bdellovibrio has a biphasic life-cycle switching from a uni-nucleoid, growth-senescent ‘attack-phase’ to a novel, multi-nucleoid filamentous ‘growth-phase’, which elongates and divides, growing saprophytically within the periplasmic space of their prey. Little is known to date about Bdellovibrio developmental processes and cell division within this periplasmic niche. Recent publications have demonstrated that bacterial cytoplasms house highly organised matrices of protein structures, called the bacterial cytoskeleton. The Bdellovibrio processes of prey-cell entry, filamentous cell growth and division coordination brings cellular morphological changes and challenges that could be coordinated by cytoskeletal elements. Green Fluorescent protein (GFP)-tagging and gene knock out approaches were used to gain insights into the function of these elements including: an Intermediate filament like protein Ccrp, which has a role in the maintenance of cell morphology; two actin homologues, which appear to function at different points in the predatory cycle, MreB1 and MreB2; and a new type of cytoskeletal element designated ‘bactofilin’, which may have a role in cell division control. Recent advances in GFP technologies have led to the development of optimised GFP variants, such as mTFP1 and mCherry. These have been used to reveal previously unseen detail of Bdellovibrio development within prey. Bdellovibrio do not follow the familiar pattern of bacterial cell division by binary fission, instead divide synchronously at multiple sites along their length, once prey resources are depleted. This yields both odd and even numbers of progeny Bdellovibrio

    Defining normal ranges and centiles for heart and respiratory rates in infants and children: A cross-sectional study of patients attending an Australian tertiary hospital paediatric emergency department

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    Key components in the assessment of a child in the emergency department ( ED ) are their heart and respiratory rates. In order to interpret these signs, practitioners must know what is normal for a particular age. The aim of this paper is to develop age-specific centiles for these parameters and to compare centiles with the previously published work of Fleming and Bonafide, and the Advanced Paediatric Life Support ( APLS ) reference ranges

    Increasing prevalence of male homosexual partnerships and practices in Britain 1990-2000: evidence from national probability surveys.

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    OBJECTIVES: To estimate the prevalence and timing of homosexual experience among British men; to explore the patterns of sexual practices and partnerships in 2000, and behavioural and attitudinal changes between 1990 and 2000 among men who have sex with men (MSM). DESIGN: Two large, stratified probability sample surveys of the general population. METHODS: Trained interviewers administered a combination of face-to-face and self-completion questionnaires to men aged 16 to 44 years resident in Britain (n = 6000 in 1990 and n = 4762 in 2000). RESULTS: In 2000, 2.8% of British men reported sex with men in the past 5 years. 46.0% of MSM reported five or more partners in the past 5 years, and 59.8% reported unprotected anal intercourse in the past year. A total of 33.0% of MSM reported one or more female partner(s) in the past year. In comparison with 1990, there was a significant increase in the proportion of MSM in the population in 2000, and among these men, in the proportion reporting receptive anal intercourse in the past year [age-adjusted odds ratio (OR), 2.08; 95% confidence interval (CI), 1.08-4.00], but no significant change in self-perceived HIV-risk (age-adjusted OR, 1.11; 95% CI, 0.49-2.51) or HIV testing in past 5 years (age-adjusted OR, 1.14; 95% CI, 0.57-2.25). CONCLUSIONS: Evidence of increasing prevalence of homosexual intercourse among the British male population coupled with increases in some HIV-risk behaviours among MSM suggests overall increasing numbers at risk in the population. Although these changes may partly reflect an increased willingness to report these behaviours, our results are consistent with increasing incidence of sexually transmitted infections and behavioural surveillance data

    The impact of phages on interspecific competition in experimental populations of bacteria

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    BACKGROUND: Phages are thought to play a crucial role in the maintenance of diversity in natural bacterial communities. Theory suggests that phages impose density dependent regulation on bacterial populations, preventing competitive dominants from excluding less competitive species. To test this, we constructed experimental communities containing two bacterial species (Pseudomonas fluorescens and Pseudomonas aeruginosa) and their phage parasites. Communities were propagated at two environmental temperatures that reversed the outcome of competition in the absence of phage. RESULTS: The evenness of coexistence was enhanced in the presence of a phage infecting the superior competitor and in the presence of phage infecting both competitors. This occurred because phage altered the balance of competitive interactions through reductions in density of the superior competitor, allowing concomitant increases in density of the weaker competitor. However, even coexistence was not equally stable at the two environmental temperatures. CONCLUSION: Phage can alter competitive interactions between bacterial species in a way that is consistent with the maintenance of coexistence. However, the stability of coexistence is likely to depend upon the nature of the constituent bacteria-bacteriophage interactions and environmental conditions

    Re-assessing the infection strategies of the entomopathogenic nematode Steinernema feltiae (Rhabditidae; Steinernematidae)

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    Previous studies have indicated that between 60 and 80% of a population of entomopathogenic nematodes do not infect their insect hosts at any one period in time. Two hypotheses explain this behaviour: the first that there is a subpopulation of non-infectious nematodes and the second that the non-infectious group is created by inhibitory cues derived from infected insects. Through an experimental approach with the Galleria mellonella-Steinernema feltiae system we show that both mechanisms operate together. When conditions for infection were optimized, the sum of individual infection behaviours was similar to the number infecting as a population, implying observed infection rates are driven by intrinsic mechanisms. In addition, there was evidence that an infected host released a chemical cue into the environment which inhibited subsequent levels of infection. This degree of inhibition was independent of the number of infecting nematodes. Both these mechanisms are dynamic, so the observed proportion of infectious nematodes depended heavily on the time of exposure. The implications of these findings for both the design of laboratory trials and the use of entomopathogenic nematodes in biological control are discussed

    Evaluating the efficacy of entomopathogenic nematodes for the biological control of crop pests: A nonequilibrium approach

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    The efficacy of entomopathogenic nematodes for biological control is assessed using deterministic models. Typically, the examination of such models involves stability analyses to determine the long‐term persistence of control. However, in agricultural systems, control is often needed within a single season. Hence, the transient dynamics of the systems were assessed under specific, short‐term control scenarios using stage‐structured models. Analyses suggest that preemptive application may be the optimum strategy if nematode mortality rates are low; applying before pest invasion can result in greater control than applying afterward. In addition, repeated applications will suppress a pest, providing the application rate exceeds a threshold. However, the period between applications affects control success, so the economic injury level of the crop and the life history of the pest should be evaluated before deciding the strategy. In all scenarios, the most important parameter influencing control is the transmission rate. These findings are applicable to more traditional biological control agents (e.g., microparasites and parasitoids), and we recommend the approach adopted here when considering their practical use. It is concluded that it is essential to consider the specific crop and pest characteristics and the definition of control success before selecting the appropriate control strategy

    Roles of cytoskeletal proteins in the predatory life cycle of Bdellovibrio bacteriovorus

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    Bdellovibrio bacteriovorus are small, predatory bacteria that grow within the periplasmic space of a host bacterium. Bdellovibrio has a biphasic life-cycle switching from a uni-nucleoid, growth-senescent ‘attack-phase’ to a novel, multi-nucleoid filamentous ‘growth-phase’, which elongates and divides, growing saprophytically within the periplasmic space of their prey. Little is known to date about Bdellovibrio developmental processes and cell division within this periplasmic niche. Recent publications have demonstrated that bacterial cytoplasms house highly organised matrices of protein structures, called the bacterial cytoskeleton. The Bdellovibrio processes of prey-cell entry, filamentous cell growth and division coordination brings cellular morphological changes and challenges that could be coordinated by cytoskeletal elements. Green Fluorescent protein (GFP)-tagging and gene knock out approaches were used to gain insights into the function of these elements including: an Intermediate filament like protein Ccrp, which has a role in the maintenance of cell morphology; two actin homologues, which appear to function at different points in the predatory cycle, MreB1 and MreB2; and a new type of cytoskeletal element designated ‘bactofilin’, which may have a role in cell division control. Recent advances in GFP technologies have led to the development of optimised GFP variants, such as mTFP1 and mCherry. These have been used to reveal previously unseen detail of Bdellovibrio development within prey. Bdellovibrio do not follow the familiar pattern of bacterial cell division by binary fission, instead divide synchronously at multiple sites along their length, once prey resources are depleted. This yields both odd and even numbers of progeny Bdellovibrio
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