Sexually selected dichromatism in the hihi Notiomystis cincta: multiple colours for multiple receivers.

Why do some bird species show dramatic sexual dichromatism in their plumage? Sexual selection is the most common answer to this question. However, other competing explanations mean it is unwise to assume that all sexual dichromatism has evolved by this mechanism. Even if sexual selection is involved, further work is necessary to determine whether dichromatism results from competition amongst rival males, or by female choice for attractive traits, or both. Here, we test whether sexually dichromatic hihi (Notiomystis cincta) plumage is currently under sexual selection, with detailed behavioural and genetic analyses of a free-living island population. Bateman gradients measured for males and females reveal the potential for sexual selection, whilst selection gradients, relating reproductive success to specific colourful traits, show that there is stabilizing selection on white ear tuft length in males. By correlating colourful male plumage with different components of reproductive success, we show that properties of yellow plumage are most likely a product of male-male competition, whilst properties of the black and white plumage are an outcome of both male-male competition and female choice. Male plumage therefore potentially signals to multiple receivers (rival males and potential mates), and this may explain the multicoloured appearance of one of the most strikingly dichromatic species in New Zealand.

Elevated high-sensitivity cardiac troponin T is associated with increased mortality after acute exacerbation of chronic obstructive pulmonary disease.

BACKGROUND: Cardiovascular co-morbidities are common in chronic obstructive pulmonary disease (COPD). Retrospective studies on selected patients have indicated that cardiac troponin elevation is frequent during acute exacerbations of COPD (AECOPD), and that this is associated with poor survival. In the present prospective study the prevalence and prognostic value of elevated cardiac troponin T (cTnT) in unselected patients with AECOPD have been investigated, using a novel high-sensitivity assay (hs-cTnT assay). METHODS AND RESULTS: 99 patients hospitalised for AECOPD were included. They were followed until death or study termination. During a median follow-up time of 1.9 years, 57 patients (58%) died. 97 patients (98%) had measurable levels of hs-cTnT and 73 (74%) had hs-cTnT above the normal range (≥14.0 ng/l). The crude mortality rates in patients having hs-cTnT <14.0, 14.0-39.9 and ≥40 ng/l were 4.6, 30.2 and 58.3 per 100 patient-years, respectively. Adjusting for relevant covariables using an extended Cox regression analysis, the HRs (95% CI) for death were 4.5 (1.2 to 16) and 8.9 (2.4 to 32) among patients having hs-cTnT 14.0-39.9 and ≥40 ng/l, respectively, compared with patients with hs-cTnT <14.0 ng/l. The association between mortality and hs-cTnT was strongly modified by heart rate at admission (p<0.001)-that is, the association between mortality and hs-cTnT was stronger among patients with tachycardia. CONCLUSION: Elevated hs-cTnT during AECOPD is frequent, and it is associated with increased mortality. The effect is stronger among patients having tachycardia than among patients with normal heart rate.

Troponin T elevation and long-term mortality after chronic obstructive pulmonary disease exacerbation.

Patients with chronic obstructive pulmonary disease (COPD) are at increased risk of cardiovascular disease, exacerbations of which increase strain on the heart. The prognostic value of elevated circulating levels of cardiac Troponins seen during COPD exacerbations has been investigated. From the Akershus hospital database, 897 patients discharged after treatment for COPD exacerbation in the period 2000-2003 were identified and followed-up until June 30, 2005. Median observation time was 1.9 yrs. In 396 patients, measurements of cardiac-specific troponin T (cTnT) were available. Levels of cTnT >/=0.04 mug.L(-1) were considered elevated. Clinical data were retrieved from patient records and date of death was obtained from the Norwegian National Registry. In order to balance the nonrandomised nature of available cTnT measurements, an exposure propensity score (EPS) for cTnT sampling was calculated and used in regression analyses. After adjusting for EPS in Cox regression analyses, elevated cTnT was significantly associated with increased all-cause mortality in the observation period, with a hazard ratio of 1.64 (95% confidence interval 1.15-2.34). In conclusion, chronic obstructive pulmonary disease patients with elevated cardiac-specific Troponin T during exacerbation are at increased risk of death after discharge.

Statin use is associated with reduced mortality in COPD.

Patients with chronic obstructive pulmonary disease (COPD) have an increased risk of ischaemic heart disease (IHD). Statins reduce mortality and morbidity in IHD. It has been hypothesised that statin treatment is associated with reduced long-term mortality in patients with COPD. Using a retrospective cohort design, 854 consecutive patients (mean age 70.8 yrs; 51.5% female) with a diagnosis of COPD exacerbation were included in the study at discharge from a Norwegian teaching hospital. Median follow-up was 1.9 yrs, during which 333 patients died. The crude mortality rate per 1,000 person-yrs was 110 in patients treated with statins, and 191 in patients not treated with statins. After adjustment for sex, age, smoking, pulmonary function and comorbidities, the hazard ratio (HR) for statin users versus statin nonusers was 0.57 (95% confidence interval 0.38-0.87). When subdividing statin users and statin nonusers into groups according to concomitant treatment with inhaled corticosteroids (ICS) the following HRs were found: 0.75 (0.58-0.98) for ICS only; 0.69 (0.36-1.3) for statins only; and 0.39 (0.22-0.67) for the combined treatment with statin and ICS compared with no such treatment. Treatment with statins was associated with improved survival after chronic obstructive pulmonary disease exacerbation, while inhaled corticosteroids appeared to increase the survival benefit associated with statin use.

Genetic effects on sperm design in the zebra finch.

Sperm design and function are important determinants of male reproductive success and are expected to be under strong selection. The way that spermatozoa phenotypes evolve is poorly understood, because there have been few studies of the quantitative genetics of sperm. Here we show, in the zebra finch Taeniopygia guttata, an extraordinary degree of inter-male variation in sperm design that is independent of sperm swimming velocity. A quantitative genetics study using data from over 900 zebra finches in a complex breeding experiment showed that sperm head, mid-piece and flagellum length are heritable, that negative genetic correlations exist between sperm traits, and that significant indirect (maternal) genetic effects exist. Selection on the zebra finch sperm phenotype may be low because sperm competition is infrequent in this species, and this, in combination with negative genetic correlations and maternal genetic effects, may account for the variation in sperm phenotype between males. These results have important implications for the evolution of sperm in other taxa.

Solar wind outflow and the chromospheric magnetic network

Observations of outflow velocities in coronal holes (regions of open coronal magnetic field) have recently been obtained with the Solar and Heliospheric Observatory (SOHO) spacecraft. Velocity maps of Ne7+ from its bright resonance line at 770 angstroms, formed at the base of the corona, show a relationship between outflow velocity and chromospheric magnetic network structure, suggesting that the solar wind is rooted at its base to this structure, emanating from localized regions along boundaries and boundary intersections of magnetic network cells. This apparent relation to the chromospheric magnetic network and the relatively large outflow velocity signatures will improve understanding of the complex structure and dynamics at the base of the corona and the source region of the solar wind.

Radiometric Calibration Tracking of the Vacuum-Ultraviolet Spectrometer SUMER During the First Year of the SOHO Mission.

Detailed radiometric calibration tracking of the vacuum-ultravioletspectrometer SUMER (from solar ultraviolet measurements of emittedradiation) was performed during the first year of the Solar andHeliospheric Observatory (SOHO) mission and will continue. Inview of the flight history of many previous solar UV instruments, thestability of calibration of the extreme-ultraviolet instruments on SOHOhas been a major concern. Results obtained during the first year ofoperation show that excellent radiometric stability has been achievedwith SUMER. These results were accomplished by stringentcleanliness and contamination-control procedures during all phases ofthe project. We describe the strategy and results of the in-flightcalibration tracking program performed with SUMER.

Continuous registration of blood oxygen tension during hemodialysis.

Continuous monitoring of blood oxygen tension was carried out during 45 hemodialyses sessions. The oxygen tension curves displayed different appearances. Some curves presented with a periodicity like sinus curves (type 1), while others (type 2) fluctuated with other appearances, or displayed straight lines. Blood pressure variations during dialysis were significantly greater during dialyses displaying type 1 curves than during those displaying type 2 curves (p values < 0.02). Due to a greater descend of S-urea during dialyses with type 1 curves than during dialyses with type 2 curves (p < 0.05) it is hypothesized, that the intensity of the dialysis treatment could be of some importance to the observed fluctuations in oxygen tension.