300 research outputs found

    High-power Soliton-induced Supercontinuum Generation and Tunable Sub-10-fs VUV Pulses from Kagome-lattice HC-PCFs

    Full text link
    We theoretically study a novel approach for soliton-induced high-power supercontinuum generation by using kagome lattice HC-PCFs filled with a noble gas. Anomalous dispersion and broad-band low loss of these fibers enable the generation of two-octave broad spectra by fs pulses, with high coherence and high spectral peak power densities up to five orders of magnitude larger than in standard PCFs. In addition, up to 20 percents of the output radiation energy forms a narrow UV/VUV band, which can be tuned by contolling the pressure in the range from 350 nm to 120 nm. In the temporal domain this corresponds to sub-10-fs UV/VUV pulses with pulse energy of few tens of microjoule, caused by the formation of a high-order soliton emitting non-solitonic radiation.Comment: 4 pages, 4 figure

    Measuring health inequality among children in developing countries: does the choice of the indicator of economic status matter?

    Get PDF
    Background Currently, poor-rich inequalities in health in developing countries receive a lot of attention from both researchers and policy makers. Since measuring economic status in developing countries is often problematic, different indicators of wealth are used in different studies. Until now, there is a lack of evidence on the extent to which the use of different measures of economic status affects the observed magnitude of health inequalities. Methods This paper provides this empirical evidence for 10 developing countries, using the Demographic and Health Surveys data-set. We compared the World Bank asset index to three alternative wealth indices, all based on household assets. Under-5 mortality and measles immunisation coverage were the health outcomes studied. Poor-rich inequalities in under-5 mortality and measles immunisation coverage were measured using the Relative Index of Inequality. Results Comparing the World Bank index to the alternative indices, we found that (1) the relative position of households in the national wealth hierarchy varied to an important extent with the asset index used, (2) observed poor-rich inequalities in under-5 mortality and immunisation coverage often changed, in some cases to an important extent, and that (3) the size and direction of this change varied per country, index, and health indicator. Conclusion Researchers and policy makers should be aware that the choice of the measure of economic status influences the observed magnitude of health inequalities, and that differences in health inequalities between countries or time periods, may be an artefact of different wealth measures used

    Subclinical thyroid dysfunction and cognitive decline in old age

    Get PDF
    <p>Background: Subclinical thyroid dysfunction has been implicated as a risk factor for cognitive decline in old age, but results are inconsistent. We investigated the association between subclinical thyroid dysfunction and cognitive decline in the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER).</p> <p>Methods: Prospective longitudinal study of men and women aged 70–82 years with pre-existing vascular disease or more than one risk factor to develop this condition (N = 5,154). Participants taking antithyroid medications, thyroid hormone supplementation and/or amiodarone were excluded. Thyroid function was measured at baseline: subclinical hyper- and hypothyroidism were defined as thyroid stimulating hormones (TSH) <0.45 mU/L or >4.50 mU/L respectively, with normal levels of free thyroxine (FT4). Cognitive performance was tested at baseline and at four subsequent time points during a mean follow-up of 3 years, using five neuropsychological performance tests.</p> <p>Results: Subclinical hyperthyroidism and hypothyroidism were found in 65 and 161 participants, respectively. We found no consistent association of subclinical hyper- or hypothyroidism with altered cognitive performance compared to euthyroid participants on the individual cognitive tests. Similarly, there was no association with rate of cognitive decline during follow-up.</p> <p>Conclusion: We found no consistent evidence that subclinical hyper- or hypothyroidism contribute to cognitive impairment or decline in old age. Although our data are not in support of treatment of subclinical thyroid dysfunction to prevent cognitive dysfunction in later life, only large randomized controlled trials can provide definitive evidence.</p&gt

    Subclinical thyroid dysfunction and cognitive decline in old age

    Get PDF
    <p>Background: Subclinical thyroid dysfunction has been implicated as a risk factor for cognitive decline in old age, but results are inconsistent. We investigated the association between subclinical thyroid dysfunction and cognitive decline in the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER).</p> <p>Methods: Prospective longitudinal study of men and women aged 70–82 years with pre-existing vascular disease or more than one risk factor to develop this condition (N = 5,154). Participants taking antithyroid medications, thyroid hormone supplementation and/or amiodarone were excluded. Thyroid function was measured at baseline: subclinical hyper- and hypothyroidism were defined as thyroid stimulating hormones (TSH) <0.45 mU/L or >4.50 mU/L respectively, with normal levels of free thyroxine (FT4). Cognitive performance was tested at baseline and at four subsequent time points during a mean follow-up of 3 years, using five neuropsychological performance tests.</p> <p>Results: Subclinical hyperthyroidism and hypothyroidism were found in 65 and 161 participants, respectively. We found no consistent association of subclinical hyper- or hypothyroidism with altered cognitive performance compared to euthyroid participants on the individual cognitive tests. Similarly, there was no association with rate of cognitive decline during follow-up.</p> <p>Conclusion: We found no consistent evidence that subclinical hyper- or hypothyroidism contribute to cognitive impairment or decline in old age. Although our data are not in support of treatment of subclinical thyroid dysfunction to prevent cognitive dysfunction in later life, only large randomized controlled trials can provide definitive evidence.</p&gt

    Aggregating behaviour in invasive Caribbean lionfish is driven by habitat complexity

    Get PDF
    Caribbean lionfish (Pterois spp.) are considered the most heavily impacting invasive marine vertebrate ever recorded. However, current management is largely inadequate, relying on opportunistic culling by recreational SCUBA divers. Culling efficiency could be greatly improved by exploiting natural aggregations, but to date this behaviour has only been recorded anecdotally, and the drivers are unknown. We found aggregations to be common in situ, but detected no conspecific attraction through visual or olfactory cues in laboratory experiments. Aggregating individuals were on average larger, but showed no further differences in morphology or life history. However, using visual assessments and 3D modelling we show lionfish prefer broad-scale, but avoid fine-scale, habitat complexity. We therefore suggest that lionfish aggregations are coincidental based on individuals’ mutual attraction to similar reef structure to maximise hunting efficiency. Using this knowledge, artificial aggregation devices might be developed to concentrate lionfish densities and thus improve culling efficiency

    Transmission of Novel Influenza A(H1N1) in Households with Post-Exposure Antiviral Prophylaxis

    Get PDF
    BACKGROUND: Despite impressive advances in our understanding of the biology of novel influenza A(H1N1) virus, little is as yet known about its transmission efficiency in close contact places such as households, schools, and workplaces. These are widely believed to be key in supporting propagating spread, and it is therefore of importance to assess the transmission levels of the virus in such settings. METHODOLOGY/PRINCIPAL FINDINGS: We estimate the transmissibility of novel influenza A(H1N1) in 47 households in the Netherlands using stochastic epidemic models. All households contained a laboratory confirmed index case, and antiviral drugs (oseltamivir) were given to both the index case and other households members within 24 hours after detection of the index case. Among the 109 household contacts there were 9 secondary infections in 7 households. The overall estimated secondary attack rate is low (0.075, 95%CI: 0.037-0.13). There is statistical evidence indicating that older persons are less susceptible to infection than younger persons (relative susceptibility of older persons: 0.11, 95%CI: 0.024-0.43. Notably, the secondary attack rate from an older to a younger person is 0.35 (95%CI: 0.14-0.61) when using an age classification of <or=12 versus >12 years, and 0.28 (95%CI: 0.12-0.50) when using an age classification of <or=18 versus >18 years. CONCLUSIONS/SIGNIFICANCE: Our results indicate that the overall household transmission levels of novel influenza A(H1N1) in antiviral-treated households were low in the early stage of the epidemic. The relatively high rate of adult-to-child transmission indicates that control measures focused on this transmission route will be most effective in minimizing the total number of infections

    Association of polymorphisms in CYP19A1 and CYP3A4 genes with lower urinary tract symptoms, prostate volume, uroflow and PSA in a population-based sample

    Get PDF
    PURPOSE: The known importance of testosterone for the development of benign prostatic hyperplasia (BPH) prompted us to test the hypothesis whether polymorphisms of two genes (CYP19A1 and CYP3A4) involved in testosterone metabolism are associated with clinical BPH-parameters. METHODS: A random sample of the population-based Herne lower urinary tract symptoms cohort was analysed. All these men underwent a detailed urological work-up. Two polymorphisms in the CYP19A1 gene [rs700518 in exon 4 (A57G); rs10046 at the 3'UTR(C268T)] and one in the 3'UTR of CYP3A4 [rs2740574 (A392G)] were determined by TaqMan assay from genomic DNA of peripheral blood. These polymorphisms were correlated to clinical and laboratory BPH-parameters. RESULTS: A total of 392 men (65.4 +/- 7.0 years; 52-79 years) were analysed. Mean International Prostate Symptom Score (IPSS; 7.5), Q (max) (15.4 ml/s), prostate volume (31 ml) and prostate specific antigen (PSA) (1.8 ng/ml) indicated a typical elderly population. Both polymorphisms in the CYP19A1 gene were not correlated to age, IPSS, Q (max), prostate volume and post-void residual volume. Serum PSA was higher in men carrying the heterozygous rs10046 genotype (2.0 +/- 0.1 ng/ml) than in those with the CC-genotype (1.7 +/- 0.2 ng/ml, P = 0.012). Men carrying one a mutated allele of the CYP3A4 gene had smaller prostates (27.0 +/- 2.0 vs. 32 +/- 0.8 ml, P = 0.02) and lower PSA levels (1.6 +/- 0.3 vs. 1.9 +/- 0.1 ng/ml). CONCLUSIONS: The inconsistent associations observed herein and for other gene polymorphisms warrant further studies. In general, the data regarding the association of gene polymorphism to BPH-parameters suggest that this disease is caused by multiple rather than a single genetic variant. A rigorous patient selection based on anatomo-pathological and hormonal profile may possible reduce the number of confounders for future studies thus enabling a more detailed assessment of the association between genetic factors and BPH-parameter

    PEARLS: Near Infrared Photometry in the JWST North Ecliptic Pole Time Domain Field

    Full text link
    We present Near-Infrared (NIR) ground-based Y, J, H, and K imaging obtained in the James Webb Space Telescope North Ecliptic Pole Time Domain Field (TDF) using the MMT-Magellan Infrared Imager and Spectrometer (MMIRS) on the MMT.These new observations cover a field of approximately 230 arcmin^2 in Y, H, and K and 313 arcmin^2 in J. Using Monte Carlo simulations we estimate a 1 sigma depth relative to the background sky of (Y, J, H, K}) = (23.80, 23.53, 23.13, 23.28) in AB magnitudes for point sources at a 95% completeness level. These observations are part of the ground-based effort to characterize this region of the sky, supplementing space-based data obtained with Chandra, NuSTAR, XMM, AstroSat, HST, and JWST. This paper describes the observations and reduction of the NIR imaging and combines these NIR data with archival imaging in the visible, obtained with the Subaru Hyper-Suprime-Cam, to produce a merged catalog of 57,501 sources. The new observations reported here, plus the corresponding multi-wavelength catalog, will provide a baseline for time-domain studies of bright sources in the TDF.Comment: 23 pages, 10 figures. Accepted for publication in ApJS. Images and catalogs available at https://doi.org/10.5281/zenodo.7934393. Data description available under ancillary files and at the Zenodo site. Added a reference, fixed typos in metadat

    PEARLS: Near-infrared Photometry in the JWST North Ecliptic Pole Time Domain Field * * Partly based on observations taken with the MMT, a joint facility operated by the University of Arizona and the Smithsonian Institution.

    Get PDF
    We present near-infrared (NIR) ground-based Y, J, H, and K imaging obtained in the James Webb Space Telescope (JWST) North Ecliptic Pole Time Domain Field (NEP TDF) using the MMT-Magellan Infrared Imager and Spectrometer on the MMT. These new observations cover a field of approximately 230 arcmin2 in Y, H, and K, and 313 arcmin2 in J. Using Monte Carlo simulations, we estimate a 1σ depth relative to the background sky of (Y, J, H, K) = (23.80, 23.53, 23.13, 23.28) in AB magnitudes for point sources at a 95% completeness level. These observations are part of the ground-based effort to characterize this region of the sky, supplementing space-based data obtained with Chandra, NuSTAR, XMM, AstroSat, Hubble Space Telescope, and JWST. This paper describes the observations and reduction of the NIR imaging and combines these NIR data with archival imaging in the visible, obtained with the Subaru Hyper-Suprime-Cam, to produce a merged catalog of 57,501 sources. The new observations reported here, plus the corresponding multiwavelength catalog, will provide a baseline for time-domain studies of bright sources in the NEP TDF
    • …
    corecore