356 research outputs found

    Same-sex sexual behaviour as a dominance display

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    Same-sex sexual behaviour (SSB) is widespread across taxa. One adaptive hypothesis to explain the occurrence and maintenance of SSB is that it acts to intensify or diminish aggression by providing males with a means to reinforce or resolve dominance. However, evidence for this hypothesis is very limited across taxa and the possibility that SSB acts as an extension of intrasexual competition remains contentious. We investigated the role of SSB in intensifying or diminishing aggression in the broad-horned flour beetle, Gnatocerus cornutus. We tested the hypothesis that SSB is an extension of male-male competition by observing how the occurrence of SSB and the stability of SSB courtship roles (i.e. whether males switched between mounting and being mounted) influenced levels of aggression within pairs. We found that, typically, males rapidly establish fixed SSB roles and moreover that the occurrence of SSB and the stability of SSB roles had a highly significant effect on levels of aggression observed within pairs. Pairs in which one male consistently mounted the other showed significantly lower levels of aggression than pairs in which neither male exhibited SSB or in which males continuously switched SSB roles and attempted to mount each other. Furthermore, males that were consistently on the receiving end of SSB demonstrated lower propensity to court females and had a lower mating success than active males. This pattern was analogous to that found in loser males as a result of fighting. Males that lost fights also courted less and had lower mating success than males that won fights. Our findings provide the first empirical support for the hypothesis that SSB is an extension of male-male competition. Furthermore, our results suggest that SSB may act as a display, allowing males to resolve dominance hierarchies without escalating into an injurious fight

    Labyrinthine window rupture as a cause of acute sensorineural hearing loss

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    Labyrinthine window rupture (LWR) is one cause of acute sensorineural hearing loss and need for early exploration is clear for good improved hearing. Acute sensorineural hearing loss of 60 dB or more treated from May 2006 to May 2010 were retrospectively analyzed. There were 21 ears of severe deafness, 18 ears of profound deafness, and 10 ears of total deafness. All patients were examined with temporal bone CT. Space-occupying lesions around the labyrinthine windows were suggestive images of LWR. Thirty-five ears were operated for LWR while 14 ears of SHL received conservative treatments. Fifty-seven percent of LWR improved 30 dB or more after sealing of both labyrinthine windows. Of the 15 markedly recovered ears, 14 ears were operated within 2 weeks from the onset. Of the five cured ears, four ears were operated within a week from the onset. As for the hearing prognosis of SHL, 88% of severe and profound deafness improved 30 dB or more but total deafness did not improve more than 30 dB. Exclusion of LWR from SHL and early surgical intervention in LWR will bring about good hearing prognosis to both LWR and SHL

    A comparison of ultrasound measurements to assess carotid atherosclerosis development in subjects with and without type 2 diabetes

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    BACKGROUND: Subjects with type 2 diabetes are at an increased risk of vascular complications. The use of carotid ultrasound remains an attractive, non-invasive method to monitor atherosclerotic disease progression and/or response to treatment in patients with type 2 diabetes, with intima-media thickness routinely used as the gold standard to detect pathology. However, alternative measurements, such as plaque area or volume, may represent a potentially more powerful approach. Thus, the objective of this study was to compare the traditional intima-media thickness measurement against the novel total plaque volume measurement in analyzing carotid atherosclerosis development in individuals with type 2 diabetes. METHODS: The case-control study included 49 Oji-Cree adults with diabetes or impaired glucose tolerance, aged 21–69, and 49 sex- and age-matched normoglycemic subjects. At baseline, metabolic variables were measured, including body mass index, waist circumference, total cholesterol:high density lipoprotein ratio, plasma triglycerides, plasma glucose, and serum insulin. Carotid ultrasound measurements, 7 years later, assessed carotid arterial intima-media thickness and total plaque volume. RESULTS: At baseline, the two groups were well matched for smoking habits, hypertension, body mass index, and waist circumference. Differences were noted in baseline measurements of total cholesterol:high density lipoprotein (P = 0.0006), plasma triglycerides (P < 0.0001) and fasting glucose (P < 0.0001). After seven years, carotid ultrasound scans revealed that total plaque volume measurements (P = 0.037), but not intima-media thickness measurements, were higher in subjects with diabetes/impaired glucose tolerance compared to the normoglycemic controls. Correlation between intima-media thickness and total plaque volume was moderate. Based on our study findings, to achieve power levels >0.70 when comparing intima-media thickness measurements for diabetics versus non-diabetics, thousands of study subjects are required. For comparing total plaque volume measurements, only hundreds of study subjects are required. CONCLUSION: The development of atherosclerotic plaque is greater in subjects with diabetes/impaired glucose tolerance. Total plaque volume appears to capture the atherosclerotic disease burden more effectively in subjects with type 2 diabetes, and would be an appropriate outcome measure for studies aimed at changing the diabetic milieu

    Socioeconomic status and health in the second half of life: findings from the German Ageing Survey

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    This study examined social inequalities in health in the second half of life. Data for empirical analyses came from the second wave of the German Ageing Survey (DEAS), an ongoing population-based, representative study of community dwelling persons living in Germany, aged 40–85 years (N = 2,787). Three different indicators for socioeconomic status (SES; education, income, financial assets as an indicator for wealth) and health (physical, functional and subjective health) were employed. It could be shown that SES was related to health in the second half of life: Less advantaged persons between 40 and 85 years of age had worse health than more advantaged persons. Age gradients varied between status indicators and health dimensions, but in general social inequalities in health were rather stable or increasing over age. The latter was observed for wealth-related absolute inequalities in physical and functional health. Only income-related differences in subjective health decreased at higher ages. The amount of social inequality in health as well as its development over age did not vary by gender and place of residence (East or West Germany). These results suggest that, in Germany, the influence of SES on health remains important throughout the second half of life

    Nutritional upgrading for omnivorous carpenter ants by the endosymbiont Blochmannia

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    <p>Abstract</p> <p>Background</p> <p>Carpenter ants (genus <it>Camponotus</it>) are considered to be omnivores. Nonetheless, the genome sequence of <it>Blochmannia floridanus</it>, the obligate intracellular endosymbiont of <it>Camponotus floridanus</it>, suggests a function in nutritional upgrading of host resources by the bacterium. Thus, the strongly reduced genome of the endosymbiont retains genes for all subunits of a functional urease, as well as those for biosynthetic pathways for all but one (arginine) of the amino acids essential to the host.</p> <p>Results</p> <p>Nutritional upgrading by <it>Blochmannia </it>was tested in 90-day feeding experiments with brood-raising in worker-groups on chemically defined diets with and without essential amino acids and treated or not with antibiotics. Control groups were fed with cockroaches, honey water and Bhatkar agar. Worker-groups were provided with brood collected from the queenright mother-colonies (45 eggs and 45 first instar larvae each). Brood production did not differ significantly between groups of symbiotic workers on diets with and without essential amino acids. However, aposymbiotic worker groups raised significantly less brood on a diet lacking essential amino acids. Reduced brood production by aposymbiotic workers was compensated when those groups were provided with essential amino acids in their diet. Decrease of endosymbionts due to treatment with antibiotic was monitored by qRT-PCR and FISH after the 90-day experimental period. Urease function was confirmed by feeding experiments using <sup>15</sup>N-labelled urea. GC-MS analysis of <sup>15</sup>N-enrichment of free amino acids in workers revealed significant labelling of the non-essential amino acids alanine, glycine, aspartic acid, and glutamic acid, as well as of the essential amino acids methionine and phenylalanine.</p> <p>Conclusion</p> <p>Our results show that endosymbiotic <it>Blochmannia </it>nutritionally upgrade the diet of <it>C. floridanus </it>hosts to provide essential amino acids, and that it may also play a role in nitrogen recycling via its functional urease. <it>Blochmannia </it>may confer a significant fitness advantage via nutritional upgrading by enhancing competitive ability of <it>Camponotus </it>with other ant species lacking such an endosymbiont. Domestication of the endosymbiont may have facilitated the evolutionary success of the genus <it>Camponotus</it>.</p

    Oral health status of adults in Southern Vietnam - a cross-sectional epidemiological study

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    Contains fulltext : 89929.pdf (publisher's version ) (Open Access)BACKGROUND: Before strategies or protocols for oral health care can be advised at population level, epidemiological information on tooth decay patterns and its effects on oral function are indispensable. The aim of this study was to investigate influences of socio-demographic variables on the prevalence of decayed, missing, filled (DMF) and sound teeth (St) and to determine the relative risk of teeth in different dental regions for D, M, and F, of adults living in urban and rural areas in Southern Vietnam. METHODS: Cross-sectional DMF and St data of 2965 dentate subjects aged 20 to 95 living in urban and rural areas in three provinces were collected by means of a self-administered questionnaire and an oral examination. The sample was stratified by age, gender, residence and province. RESULTS: The percentage of subjects having missing teeth was high for all ages while it was low for subjects with decayed and filled teeth. The mean number of missing teeth increased gradually by age from approximately 1 in each jaw at the age of 20 to 8 at the age of 80. The number of decayed teeth was relative low at all ages, being highest in molars at young ages. The mean number of filled teeth was extremely low at all ages in all dental regions. Every additional year of age gives a significantly lower chance for decay, a higher chance for missing, and a lower chance for filled teeth. Molars had a significantly higher risk for decay, missing and filled than premolars and anterior teeth. Females had significantly higher risk for decayed and filled teeth, and less chance for missing teeth than males. Urban subjects presented lower risk for decay, but approximately 4 times greater chance for having fillings than rural subjects. Low socio-economic status (SES) significantly increased the chance for missing anterior and molar teeth; subjects with high SES had more often fillings. CONCLUSIONS: The majority of adults of Southern Vietnam presented a reduced dentition. The combination of low numbers of filled teeth and relative high numbers of decayed and missing teeth indicates that the main treatment for decay is extraction. Molars are more at risk for being decayed or missing than premolars and anterior teeth

    A comprehensive evaluation of food fortification with folic acid for the primary prevention of neural tube defects

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    BACKGROUND: Periconceptional use of vitamin supplements containing folic acid reduces the risk of a neural tube defect (NTD). In November 1998, food fortification with folic acid was mandated in Canada, as a public health strategy to increase the folic acid intake of all women of childbearing age. We undertook a comprehensive population based study in Newfoundland to assess the benefits and possible adverse effects of this intervention. METHODS: This study was carried out in women aged 19–44 years and in seniors from November 1997 to March 1998, and from November 2000 to March 2001. The evaluation was comprised of four components: I) Determination of rates of NTDs; II) Dietary assessment; III) Blood analysis; IV) Assessment of knowledge and use of folic acid supplements. RESULTS: The annual rates of NTDs in Newfoundland varied greatly between 1976 and 1997, with a mean rate of 3.40 per 1,000 births. There was no significant change in the average rates between 1991–93 and 1994–97 (relative risk [RR] 1.01, 95% confidence interval [CI] 0.76–1.34). The rates of NTDs fell by 78% (95% CI 65%–86%) after the implementation of folic acid fortification, from an average of 4.36 per 1,000 births during 1991–1997 to 0.96 per 1,000 births during 1998–2001 (RR 0.22, 95% CI 0.14–0.35). The average dietary intake of folic acid due to fortification was 70 μg/day in women aged 19–44 years and 74 μg/day in seniors. There were significant increases in serum and RBC folate levels for women and seniors after mandatory fortification. Among seniors, there were no significant changes in indices typical of vitamin B(12 )deficiencies, and no evidence of improved folate status masking haematological manifestations of vitamin B(12 )deficiency. The proportion of women aged 19–44 years taking a vitamin supplement containing folic acid increased from 17% to 28%. CONCLUSIONS: Based on these findings, mandatory food fortification in Canada should continue at the current levels. Public education regarding folic acid supplement use by women of childbearing age should also continue

    A study of young peoples' attitudes to opportunistic Chlamydia testing in UK general practice

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    <p>Abstract</p> <p>Objective</p> <p>The objective of this study was to assess young people's perceptions of being offered a chlamydia screening test in United Kingdom (UK) general practice.</p> <p>Methods</p> <p>This is qualitative study that uses focus groups and individual interviews with young adults (age 16 – 18) to assess their views.</p> <p>Results</p> <p>These young adults were a difficult group to gain access to. Two focus groups, one in a school, the other in a general practice (family practice), and 2 individual interviews were undertaken (total sample 18). Respondents were unfamiliar with Chlamydia, but broadly aware of sexually transmitted infections. General practice (family practice) was perceived as an acceptable place to deliver opportunistic screening, but participants felt that tests should not be initiated by GP receptionists. Novel delivery routes such as schools and "Pub"/Bar dispensing machines were discussed. Issues around stigma and confidentiality were also raised.</p> <p>Conclusion</p> <p>Opportunistic Chlamydia screening in UK general practice (family practic seems acceptable to young adults. While this is a difficult group to gain access to for research, attempts need to made to ensure acceptability to users of this programme.</p
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