296 research outputs found
Physiological Costs of Repetitive Courtship Displays in Cockroaches Handicap Locomotor Performance
Courtship displays are typically thought to have evolved via female choice, whereby females select mates based on the characteristics of a display that is expected to honestly reflect some aspect of the male’s quality. Honesty is typically enforced by mechanistic costs and constraints that limit the level at which a display can be performed. It is becoming increasingly apparent that these costs may be energetic costs involved in the production of dynamic, often repetitive displays. A female attending to such a display may thus be assessing the physical fitness of a male as an index of his quality. Such assessment would provide information on his current physical quality as well as his ability to carry out other demanding activities, qualities with which a choosy female should want to provision her offspring. In the current study we use courtship interactions in the Cuban burrowing cockroach, Byrsotria fumigata to directly test whether courtship is associated with a signaler’s performance capacity. Males that had produced courtship displays achieved significantly lower speeds and distances in locomotor trials than non-courting control males. We also found that females mated more readily with males that produced a more vigorous display. Thus, males of this species have developed a strategy where they produce a demanding courtship display, while females choose males based on their ability to produce this display. Courtship displays in many taxa often involve dynamic repetitive actions and as such, signals of stamina in courtship may be more widespread than previously thought
Angiotensin converting enzyme gene polymorphism is associated with severity of coronary artery disease in men with high total cholesterol levels
This study examines whether renin-angiotensin-aldosterone system gene polymorphisms: ACE (encoding for angiotensin converting enzyme) c.2306-117_404 I/D, AGTR1 (encoding for angiotensin II type-1 receptor) c.1080*86A>C and CYP11B2 (encoding for aldosterone synthase) c.-344C>T are associated with the extension of coronary atherosclerosis in a group of 647 patients who underwent elective coronary angiography. The extension of CAD was evaluated using the Gensini score. The polymorphisms were determined by PCR and RFLP assays. The associations between genotypes and the extent of coronary atherosclerosis were tested by the Kruskal-Wallis test, followed by pairwise comparisons using Wilcoxon test. The population has been divided into groups defined by: sex, smoking habit, past myocardial infarction, BMI (>, ≤ 25), age (>, ≤ 55), diabetes mellitus, level of total cholesterol (>, ≤ 200 mg/dl), LDL cholesterol (>, ≤ 130 mg/dl), HDL cholesterol (>, ≤ 40 mg/dl), triglycerides (>, ≤ 150 mg/dl). Significant associations between the ACE c.2306-117_404 I/D polymorphism and the Gensini score in men with high total cholesterol levels (PKruskal-Wallis = 0.008; Padjusted = 0.009), high level of LDL cholesterol (PKruskal-Wallis = 0.016; Padjusted = 0.028) and low level of HDL cholesterol (PKruskal-Wallis = 0.04; Padjusted = 0.055) have been found. No association between the AGTR1 c.1080*86A>C and CYP11B2 c.-344C>T and the Gensini score has been found. These results suggest that men who carry ACE c.2306-117_404 DD genotype and have high total cholesterol, high LDL cholesterol and low HDL cholesterol levels may be predisposed to the development of more severe CAD
A phase I study of the nitroimidazole hypoxia marker SR4554 using 19F magnetic resonance spectroscopy
SR4554 is a fluorine-containing 2-nitroimidazole, designed as a hypoxia marker detectable with 19F magnetic resonance spectroscopy (MRS). In an initial phase I study of SR4554, nausea/vomiting was found to be dose-limiting, and 1400 mg m−2 was established as MTD. Preliminary MRS studies demonstrated some evidence of 19F retention in tumour. In this study we investigated higher doses of SR4554 and intratumoral localisation of the 19F MRS signal. Patients had tumours 3 cm in diameter and 4 cm deep. Measurements were performed using 1H/19F surface coils and localised 19F MRS acquisition. SR4554 was administered at 1400 mg m−2, with subsequent increase to 2600 mg m−2 using prophylactic metoclopramide. Spectra were obtained immediately post infusion (MRS no. 1), at 16 h (MRS no. 2) and 20 h (MRS no. 3), based on the SR4554 half-life of 3.5 h determined from a previous study. 19Fluorine retention index (%) was defined as (MRS no. 2/MRS no. 1)*100. A total of 26 patients enrolled at: 1400 (n=16), 1800 (n=1), 2200 (n=1) and 2600 mg m−2 (n=8). SR4554 was well tolerated and toxicities were all grade 1; mean plasma elimination half-life was 3.7±0.9 h. SR4554 signal was seen on both unlocalised and localised MRS no. 1 in all patients. Localised 19F signals were detected at MRS no. 2 in 5 out of 9 patients and 4 out of 5 patients at MRS no. 3. The mean retention index in tumour was 13.6 (range 0.6-43.7) compared with 4.1 (range 0.6-7.3) for plasma samples taken at the same times (P=0.001) suggesting 19F retention in tumour and, therefore, the presence of hypoxia. We have demonstrated the feasibility of using 19F MRS with SR4554 as a potential method of detecting hypoxia. Certain patients showed evidence of 19F retention in tumour, supporting further development of this technique for detection of tumour hypoxia
A case report: Giant cystic parathyroid adenoma presenting with parathyroid crisis after Vitamin D replacement
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A Search for Dark Higgs Bosons
Recent astrophysical and terrestrial experiments have motivated the proposal
of a dark sector with GeV-scale gauge boson force carriers and new Higgs
bosons. We present a search for a dark Higgs boson using 516 fb-1 of data
collected with the BABAR detector. We do not observe a significant signal and
we set 90% confidence level upper limits on the product of the Standard
Model-dark sector mixing angle and the dark sector coupling constant.Comment: 7 pages, 5 postscript figures, published version with improved plots
for b/w printin
The role of gonadotrophin-releasing hormone antagonists in the treatment of patients with advanced hormone-dependent prostate cancer in the UK.
PURPOSE: Comparing gonadotrophin-releasing hormone (GnRH) antagonists and agonists as androgen deprivation therapy for advanced prostate cancer (PC). METHODS: This article stems from a round-table meeting in December 2014 to compare the properties of GnRH agonists and antagonists in the published literature in order to identify the patient groups most likely to benefit from GnRH antagonist therapy. A broad PubMed and congress abstract search was carried out in preparation for the meeting to ensure that the latest data and opinion were available for the discussions. RESULTS: In randomised, controlled trials, GnRH antagonist therapy provides more rapid suppression of luteinising hormone, follicle-stimulating hormone and testosterone than GnRH agonist treatment. Compared with the GnRH agonist, there is evidence of improved disease control by a GnRH antagonist, with longer interval to prostate-specific antigen progression and greater reduction of serum alkaline phosphatase. In a post hoc analysis of six randomised trials, the risk of cardiac events within 1Â year of initiating therapy was significantly lower among men receiving GnRH antagonist than agonist. Pre-clinical laboratory data suggest a number of mechanisms whereby GnRH antagonist therapy may benefit men with pre-existing cardiovascular disease (CVD), the most plausible hypothesis being that, unlike GnRH agonists, GnRH antagonists do not activate T lymphocytes, which act to increase atherosclerotic plaque rupture. CONCLUSION: When making treatment decisions, clinicians should consider comorbidities, particularly CVD, in addition to effects on PC. GnRH antagonists may be appropriate in patients with significant CV risk, existing osteopenia, lower urinary tract symptoms and significant metastatic disease
How Abnormal Is the Behaviour of Captive, Zoo-Living Chimpanzees?
Background. Many captive chimpanzees (Pan troglodytes) show a variety of serious behavioural abnormalities, some of which have been considered as possible signs of compromised mental health. The provision of environmental enrichments aimed at reducing the performance of abnormal behaviours is increasing the norm, with the housing of individuals in (semi-)natural social groups thought to be the most successful of these. Only a few quantitative studies of abnormal behaviour have been conducted, however, particularly for the captive population held in zoological collections. Consequently, a clear picture of the level of abnormal behaviour in zoo-living chimpanzees is lacking.
Methods. We present preliminary findings from a detailed observational study of the behaviour of 40 socially-housed zoo-living chimpanzees from six collections in the United States of America and the United Kingdom. We determined the prevalence, diversity, frequency, and duration of abnormal behaviour from 1200 hours of continuous behavioural data collected by focal animal sampling.
Results, conclusion, and significance. Our overall finding was that abnormal behaviour was present in all sampled individuals across six independent groups of zoo-living chimpanzees, despite the differences between these groups in size, composition, housing, etc. We found substantial variation between individuals in the frequency and duration of abnormal behaviour, but all individuals engaged in at least some abnormal behaviour and variation across individuals could not be explained by sex, age, rearing history or background (defined as prior housing conditions). Our data support a conclusion that, while most behaviour of zoo-living chimpanzees is ‘normal’ in that it is typical of their wild counterparts, abnormal behaviour is endemic in this population despite enrichment efforts. We suggest there is an urgent need to understand how the chimpanzee mind copes with captivity, an issue with both scientific and welfare implications
Allometry of the Duration of Flight Feather Molt in Birds
Replacement of flight feathers takes disproportionately more time for large birds than it does for small birds, because feather length increases with body size almost twice as fast as feather growth rate increases
Entrepreneurs’ achieved success: developing a multi-faceted measure
Firm performance is typically measured via objective financial indicators. However, researchers increasingly acknowledge that entrepreneurs do not measure their success solely in financial terms but that a range of often subjective indicators matter to them. This article contributes to the debate on entrepreneurial performance by studying how entrepreneurs assess their achieved success. ‘Entrepreneurs’ achieved success’ was conceptualized as a multi-faceted construct that includes entrepreneurs’ self-reported achievement of firm performance, workplace relationships, personal fulfilment, community impact, and personal financial rewards. It was measured via the Subjective Entrepreneurial Success–Achievement Scale (SES-AS). Over the course of three studies (N = 390) the factorial structure of ‘entrepreneurs’ achieved success’ was established and largely replicated in two cultures. Based on a nomological network, we documented relationships among ‘entrepreneurs’ achieved success’, quasi-objective indicators of firm performance, and entrepreneurs’ financial satisfaction, creativity, and health. Based on our research, we propose a new conceptual framework to study performance in the context of entrepreneurship. This framework acknowledges both the success criteria that entrepreneurs wish to achieve and those that they actually achieve, and extends our understanding of firm performance
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