206 research outputs found

    Prenatal inflammation exposure-programmed cardiovascular diseases and potential prevention

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    In recent years, the rapid development of medical and pharmacological interventions has led to a steady decline in certain noncommunicable chronic diseases (NCDs), such as cancer. However, the overall incidence of cardiovascular diseases (CVDs) has not seemed to decline. CVDs have become even more prevalent in many countries and represent a global health threat and financial burden. An increasing number of epidemiological and experimental studies have demonstrated that maternal insults not only can result in birth defects but also can cause developmental functional defects that contribute to adult NCDs. In the current review, we provide an overview of evidence from both epidemiological investigations and experimental animal studies supporting the concept of developmental reprogramming of adult CVDs in offspring that have experienced prenatal inflammation exposure (PIE) during fetal development (PIE-programmed CVDs), a disease-causing event that has not been effectively controlled. This review describes the epidemiological observations, data from animal models, and related mechanisms for the pathogenesis of PIE-programmed CVDs. In addition, the potential therapeutic interventions of PIE-programmed CVDs are discussed. Finally, we also deliberate the need for future mechanistic studies and biomarker screenings in this important field, which creates a great opportunity to combat the global increase in CVDs by managing the adverse effects of inflammation for prepregnant and pregnant individuals who are at risk for PIE-programmed CVDs

    Analysis of factors influencing spatiotemporal differentiation of the NDVI in the upper and middle reaches of the Yellow River from 2000 to 2020

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    Surface vegetation represents a link between the atmosphere, water, and human society. The quality of the ecological environment in the upper and middle reaches of the Yellow River (UMRYR) has a direct impact on the downstream basin. However, only few studies have investigated vegetation changes in the UMRYR. Therefore, we used the coefficient of variation and linear regression analyses to investigate spatiotemporal variations in the normalized difference vegetation index (NDVI). Further, we used the geographical detector model (GDM) to determine the spatial heterogeneity of the NDVI and its driving factors and then investigated the factors driving the spatial distribution of the NDVI in different climatic zones and vegetation types. The results showed that the NDVI in the UMRYR was high during the study period. The NDVI was distributed in a spatially heterogeneous manner, and it decreased from the southeast to the northwest. We observed severe degradation in the southeast, mild degradation in the northwest and the Yellow River source region, and substantial vegetation recovery in the central basin. Precipitation and vegetation type drove the spatial distribution of the NDVI. Natural factors had higher influence than that of anthropogenic factors, but the interactions between the natural and anthropogenic factors exhibited non-linear and bivariate enhancements. Inter-annual variations in precipitation were the main natural factor influencing inter-annual NDVI variations, while precipitation and anthropogenic ecological restoration projects jointly drove NDVI changes in the UMRYR. This study provides a better understanding of the current status of the NDVI and mechanisms driving vegetation restoration in the UMRYR

    Design of mission adaptive landing gear for near space travel lander

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    The ability to perform vertical takeoff and landing reliably and safely is of great concern for a near space travel lander carrying passengers. Oblique and uneven terrains can severely limit the degree of landing safety, so mission adaptive landing gear is designed and analyzed for its function of automatic adjustment before touchdown. The legs of mission adaptive landing gear are composed of shock absorbers and actuating cylinders, which can adjust angles of the main struts relative to the capsule under control, ensuring all feet touch the irregular surface together. Compared with a conventional landing gear, scaled test and dynamic simulation in three typical conditions verify that the new design can reduce the rotation angle and the translational motion of the capsule to less than 3 degrees and 1 meter, respectively. For buffer process, the overall design reduces peak load of the lander by more than 24 %, enhances efficiency of the shock absorber to more than 85 % and optimizes stroke lengths of shock absorbers. While landing on a slope with an angle of less than 31 degrees, mission adaptive landing gear can ensure the capsule’s maximum overload less than 5 and the capsule’s attitude angle less than 20 degrees, respectively. Landing performance shows that mission adaptive landing gear is robust to uncertain conditions of the landing surface

    Photometric Metallicity Calibration with SDSS and SCUSS and its Application to distant stars in the South Galactic Cap

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    Based on SDSS g, r and SCUSS (South Galactic Cap of u-band Sky Survey) uu photometry, we develop a photometric calibration for estimating the stellar metallicity from u−gu-g and g−rg-r colors by using the SDSS spectra of 32,542 F- and G-type main sequence stars, which cover almost 37003700 deg2^{2} in the south Galactic cap. The rms scatter of the photometric metallicity residuals relative to spectrum-based metallicity is 0.140.14 dex when g−r<0.4g-r<0.4, and 0.160.16 dex when g−r>0.4g-r>0.4. Due to the deeper and more accurate magnitude of SCUSS uu band, the estimate can be used up to the faint magnitude of g=21g=21. This application range of photometric metallicity calibration is wide enough so that it can be used to study metallicity distribution of distant stars. In this study, we select the Sagittarius (Sgr) stream and its neighboring field halo stars in south Galactic cap to study their metallicity distribution. We find that the Sgr stream at the cylindrical Galactocentric coordinate of R∼19R\sim 19 kpc, ∣z∣∼14\left| z\right| \sim 14 kpc exhibits a relative rich metallicity distribution, and the neighboring field halo stars in our studied fields can be modeled by two-Gaussian model, with peaks respectively at [Fe/H]=−1.9=-1.9 and [Fe/H]=−1.5=-1.5.Comment: 8 pages, 7 figures, Accepted for publication in MNRA

    Project Overview of the Beijing-Arizona Sky Survey

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    The Beijing-Arizona Sky Survey (BASS) is a wide-field two-band photometric survey of the Northern Galactic Cap using the 90Prime imager on the 2.3 m Bok telescope at Kitt Peak. It is a four-year collaboration between the National Astronomical Observatory of China and Steward Observatory, the University of Arizona, serving as one of the three imaging surveys to provide photometric input catalogs for target selection of the Dark Energy Spectroscopic Instrument (DESI) project. BASS will take up to 240 dark/grey nights to cover an area of about 5400 deg2^2 in the gg and rr bands. The 5σ\sigma limiting AB magnitudes for point sources in the two bands, corrected for the Galactic extinction, are 24.0 and 23.4 mag, respectively. BASS, together with other DESI imaging surveys, will provide unique science opportunities that cover a wide range of topics in both Galactic and extragalactic astronomy.Comment: 10 pages, submitted to PAS

    The Galactic extinction and reddening from the South Galactic Cap U-band Sky Survey: u band galaxy number counts and u−ru-r color distribution

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    We study the integral Galactic extinction and reddening based on the galaxy catalog of the South Galactic Cap U-band Sky Survey (SCUSS), where uu band galaxy number counts and u−ru-r color distribution are used to derive the Galactic extinction and reddening respectively. We compare these independent statistical measurements with the reddening map of \citet{Schlegel1998}(SFD) and find that both the extinction and reddening from the number counts and color distribution are in good agreement with the SFD results at low extinction regions (E(B−V)SFD<0.12E(B-V)^{SFD}<0.12 mag). However, for high extinction regions (E(B−V)SFD>0.12E(B-V)^{SFD}>0.12 mag), the SFD map overestimates the Galactic reddening systematically, which can be approximated by a linear relation ΔE(B−V)=0.43[E(B−V)SFD−0.12\Delta E(B-V)= 0.43[E(B-V)^{SFD}-0.12]. By combing the results of galaxy number counts and color distribution together, we find that the shape of the Galactic extinction curve is in good agreement with the standard RV=3.1R_V=3.1 extinction law of \cite{ODonnell1994}
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