258 research outputs found

    Differential Reproductive Success and Body Size in !Kung San People from Northern Namibia

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    The associations patterns between reproductive success, measured by the total number of offspring, number of living offspring and number of dead offspring, and parental body size, estimated by stature, body weight and Body mass index, were tested in 65 female and 103 male members of a !Kung San population ageing between 25 and 40 years (x = 30.2 yr.) from northern Namibia. In both sexes a significant interaction between fertility patterns and body dimensions was found. Nevertheless, the association patterns differed markedly between the two sexes. While in males tallness and an improved weight status was associated significantly with a higher number of surviving offspring, smaller and lighter females had significantly more surviving children. In males a directional selection towards increased stature and better weight status is in accordance with the well known secular trend of acceleration. In females first of all the postpartum changes in body composition and body weight, resulting from exhausting infant feeding practices seem to support the maternal depletion hypothesis

    Use of the Oral Contraceptive Pill by Austrian Adolescents with Emphasis on the Age of Onset, Side Effects, Compliance and Lifestyle

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    The present study investigated the use of the oral contraceptive pill in 880 Austrian high school girls. All participants filled in a questionnaire on lifestyle and menarche. Furthermore, subjects on the pill were asked about their preparation, age at first use, reasons why they take it, side effects and oral contraceptive compliance. All 139 subjects on the pill used low dose monophasic preparations. The girls started the pill at a mean age of 16.0 0.9 years for contraceptive and therapeutic reasons. The most commonly noted side effects were weight gain, an increase in breast size, fatigue and depression. The results also indicate that most users comply sufficiently. Regarding lifestyle, it can be stated that there is a correlation between the use of the pill and smoking, the frequency of consuming alcoholic drinks and being physically active

    Greenhouse gas profiling by infrared-laser and microwave occultation: retrieval algorithm and demonstration results from end-to-end simulations

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    Measuring greenhouse gas (GHG) profiles with global coverage and high accuracy and vertical resolution in the upper troposphere and lower stratosphere (UTLS) is key for improved monitoring of GHG concentrations in the free atmosphere. In this respect a new satellite mission concept adding an infrared-laser part to the already well studied microwave occultation technique exploits the joint propagation of infrared-laser and microwave signals between Low Earth Orbit (LEO) satellites. This synergetic combination, referred to as LEO-LEO microwave and infrared-laser occultation (LMIO) method, enables to retrieve thermodynamic profiles (pressure, temperature, humidity) and accurate altitude levels from the microwave signals and GHG profiles from the simultaneously measured infrared-laser signals. However, due to the novelty of the LMIO method, a retrieval algorithm for GHG profiling is not yet available. Here we introduce such an algorithm for retrieving GHGs from LEO-LEO infrared-laser occultation (LIO) data, applied as a second step after retrieving thermodynamic profiles from LEO-LEO microwave occultation (LMO) data. We thoroughly describe the LIO retrieval algorithm and unveil the synergy with the LMO-retrieved pressure, temperature, and altitude information. We furthermore demonstrate the effective independence of the GHG retrieval results from background (a priori) information in discussing demonstration results from LMIO end-to-end simulations for a representative set of GHG profiles, including carbon dioxide (CO<sub>2</sub>), water vapor (H<sub>2</sub>O), methane (CH<sub>4</sub>), and ozone (O<sub>3</sub>). The GHGs except for ozone are well retrieved throughout the UTLS, while ozone is well retrieved from about 10 km to 15 km upwards, since the ozone layer resides in the lower stratosphere. The GHG retrieval errors are generally smaller than 1% to 3% r.m.s., at a vertical resolution of about 1 km. The retrieved profiles also appear unbiased, which points to the climate benchmarking capability of the LMIO method. This performance, found here for clear-air atmospheric conditions, is unprecedented for vertical profiling of GHGs in the free atmosphere and encouraging for future LMIO implementation. Subsequent work will examine GHG retrievals in cloudy air, addressing retrieval performance when scanning through intermittent upper tropospheric cloudiness

    Errors in GNSS radio occultation data: relevance of the measurement geometry and obliquity of profiles

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    Atmospheric profiles retrieved from GNSS (Global Navigation Satellite System) radio occultation (RO) measurements are increasingly used to validate other measurement data. For this purpose it is important to be aware of the characteristics of RO measurements. RO data are frequently compared with vertical reference profiles, but the RO method does not provide vertical scans through the atmosphere. The average elevation angle of the tangent point trajectory (which would be 90° for a vertical scan) is about 40° at altitudes above 70 km, decreasing to about 25° at 20 km and to less than 5° below 3 km. In an atmosphere with high horizontal variability we can thus expect noticeable representativeness errors if the retrieved profiles are compared with vertical reference profiles. We have performed an end-to-end simulation study using high-resolution analysis fields (T799L91) from the European Centre for Medium-Range Weather Forecasts (ECMWF) to simulate a representative ensemble of RO profiles via high-precision 3-D ray tracing. Thereby we focused on the dependence of systematic and random errors on the measurement geometry, specifically on the incidence angle of the RO measurement rays with respect to the orbit plane of the receiving satellite, also termed azimuth angle, which determines the obliquity of RO profiles. We analyzed by how much errors are reduced if the reference profile is not taken vertical at the mean tangent point but along the retrieved tangent point trajectory (TPT) of the RO profile. The exact TPT can only be determined by performing ray tracing, but our results confirm that the retrieved TPT – calculated from observed impact parameters – is a very good approximation to the "true" one. Systematic and random errors in RO data increase with increasing azimuth angle, less if the TPT is properly taken in to account, since the increasing obliquity of the RO profiles leads to an increasing sensitivity to departures from horizontal symmetry. Up to an azimuth angle of 30°, however, this effect is small, even if the RO profiles are assumed to be vertical. For applications requiring highest accuracy and precision it is advisable to exclude RO profiles with ray incidence angles beyond an azimuth of 50°. Errors in retrieved atmospheric profiles decrease significantly, by up to a factor of 2, if the RO data are exploited along the retrieved TPT. The tangent point trajectory of RO profiles should therefore be exploited whenever this is possible

    The Polycystic Ovary Syndrome – A Medical Condition but also an Important Psychosocial Problem

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    PCOS, the leading cause of anovulatory infertility that affects up to one fifth of the female population, is a complex chronic disease of genetic as well as environmental determination, but still unclear etiology. Besides of infertility, PCOS leads to menstrual dysfunctions, hirsutism and obesity – symptoms that are known to cause profound psychosocial distress. The present paper review the problematic of etiology and symptom expression of PCOS, which is not only a disease needing medical treatment but also a psychosocial problem for the affected women. PCOS may not only coinduced by psychosocial factors, the main symptoms of PCOS such as infertility, menstrual dysfunctions, hirsutism and obesity cause by themselves increased psychosocial stress

    Sexual Dimorphism in Body Composition, Weight Status and Growth in Prepubertal School Children from Rural Areas of Eastern Austria

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    Sexual dimorphism in stature, weight status and body composition were analyzed in a sample of 398 prepubertal children (213 girls, 185 boys) ageing between 7 and 10. Furthermore the prevalence of overweight was tested. Body composition parameters were determined using TBF 105 Body composition analyzer according to BIA-method. Highly significant sex differences in body composition were observed (p < 0.001). In contrast, stature, weight and BMI showed no significant differences between the two sexes. Nevertheless, a significant higher portion (p < 0.05) of girls (29%) corresponded to the definition overweight according to ASNS (Austrian Survey of Nutritional Status), while only 20% of the boys felt into the category overweight. The results of the present study showed not only significant sex differences in body composition, especially in fat mass, long before puberty onset, but also a significantly higher prevalence of overweight among prepubertal girls in comparison to prepubertal boys

    Small catchment runoff sensitivity to station density and spatial interpolation: Hydrological modeling of heavy rainfall using a dense rain Gauge network

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    Precipitation is the most important input to hydrological models, and its spatial variability can strongly influence modeled runoff. The highly dense station network WegenerNet (0.5 stations per km2) in southeastern Austria offers the opportunity to study the sensitivity of modeled runoff to precipitation input. We performed a large set of runoff simulations (WaSiM model) using 16 subnetworks with varying station densities and two interpolation schemes (inverse distance weighting, Thiessen polygons). Six representative heavy precipitation events were analyzed, placing a focus on small subcatchments (10–30 km2) and different event durations. We found that the modeling performance generally improved when the station density was increased up to a certain resolution: a mean nearest neighbor distance of around 6 km for long-duration events and about 2.5 km for short-duration events. However, this is not always true for small subcatchments. The sufficient station density is clearly dependent on the catchment area, event type, and station distribution. When the network is very dense (mean distance &lt; 1.7 km), any reasonable interpolation choice is suitable. Overall, the station density is much more important than the interpolation scheme. Our findings highlight the need to study extreme precipitation characteristics in combination with runoff modeling to decompose precipitation uncertainties more comprehensively
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