211 research outputs found
Linking satellite derived LAI patterns with subsoil heterogeneity using large-scale ground-based electromagnetic induction measurements
Patterns in crop development and yield are often directly related to lateral and vertical changes in soil texture
causing changes in available water and resource supply for plant growth, especially under dry conditions. Relict
geomorphologic features, such as old river channels covered by shallow sediments can challenge assumptions of
uniformity in precision agriculture, subsurface hydrology, and crop modeling. Hence a better detection of these
subsurface structures is of great interest. In this study, the origins of narrow and undulating leaf area index
(LAI) patterns showing better crop performance in large scale multi-temporal satellite imagery were for the
first time interpreted by proximal soil sensor data. A multi-receiver electromagnetic induction (EMI) sensor measuring
soil apparent electrical conductivity (ECa) for six depths of exploration (DOE) ranging from 0–0.25 to
0–1.9 m was used as reconnaissance soil survey tool in combination with selected electrical resistivity tomography
(ERT) transects, and ground truth texture data to investigate lateral and vertical changes of soil properties at
ten arable fields. The moderate to excellent spatial consistency (R2 0.19–0.82) of ECa patterns and LAI crop marks that indicate a higher water storage capacity as well as the increased correlations between large-offset ECa data
and the subsoil clay content and soil profile depth, implies that along this buried paleo-river structure the subsoil is mainly responsible for better crop development in drought periods. Furthermore, observed stagnant water in
the subsoil indicates that this paleo-river structure still plays an important role in subsurface hydrology. These
insights should be considered and implemented in local hydrological as well as crop models
Prevalence of parental supply of alcohol to minors: a systematic review
Parental supply of alcohol to minors (i.e. those under the legal drinking age) is often perceived by parents as protective against harms from drinking, despite evidence linking it with adverse alcohol-related outcomes. This systematic review describes the prevalence of parental supply of alcohol, as reported in the international literature. The review was registered with PROSPERO (CRD42020218754). We searched seven online databases (Medline, Embase, PsycINFO, CINAHL, Scopus, Web of Science and Public Health Database) and grey literature from January 2011 to December 2022 and assessed the risk of bias with the JBI Critical Appraisal Checklist. Among 58 articles included in narrative synthesis from 29 unique datasets, there was substantial variation in the definition and measurement of parental supply of alcohol. Overall prevalence rates ranged from 7.0 to 60.0% for minor-report samples, and from 24.0 to 8.0% for parent-report samples. Data indicate that parental supply prevalence is generally proportionately higher for older minors or later-stage students, for girls, and has increased over time among minors who report drinking. Literature on the prevalence of parental supply of alcohol is robust in quantity but inconsistent in quality and reported prevalence. Greater consistency in defining and measuring parental supply is needed to better inform health promotion initiatives aimed at increasing parents' awareness.Shannen van der Kruk, Nathan J. Harrison, Ashlea Bartram, Skye Newton, Caroline Miller, Robin Room, Ian Olver, and Jacqueline Bowde
Effect of galaxy mergers on star-formation rates
Context. Galaxy mergers and interactions are an integral part of our basic understanding of how galaxies grow and evolve over time. However, the effect that galaxy mergers have on star-formation rates (SFRs) is contested, with observations of galaxy mergers showing reduced, enhanced, and highly enhanced star formation. Aims. We aim to determine the effect of galaxy mergers on the SFR of galaxies using statistically large samples of galaxies, totalling over 200 000, which is over a large redshift range from 0.0 to 4.0. Methods. We trained and used convolutional neural networks to create binary merger identifications (merger or non-merger) in the SDSS, KiDS, and CANDELS imaging surveys. We then compared the SFR, with the galaxy main sequence subtracted, of the merging and non-merging galaxies to determine what effect, if any, a galaxy merger has on SFR. Results. We find that the SFR of merging galaxies are not significantly different from the SFR of non-merging systems. The changes in the average SFR seen in the star-forming population when a galaxy is merging are small, of the order of a factor of 1.2. However, the higher the SFR is above the galaxy main sequence, the higher the fraction is for galaxy mergers. Conclusions. Galaxy mergers have little effect on the SFR of the majority of merging galaxies compared to the non-merging galaxies. The typical change in SFR is less than 0.1 dex in either direction. Larger changes in SFR can be seen but are less common. The increase in merger fraction as the distance above the galaxy main sequence increases demonstrates that galaxy mergers can induce starbursts
Wide-Field InfraRed Survey Telescope (WFIRST) Final Report
In December 2010, NASA created a Science Definition Team (SDT) for WFIRST,
the Wide Field Infra-Red Survey Telescope, recommended by the Astro 2010
Decadal Survey as the highest priority for a large space mission. The SDT was
chartered to work with the WFIRST Project Office at GSFC and the Program Office
at JPL to produce a Design Reference Mission (DRM) for WFIRST. Part of the
original charge was to produce an interim design reference mission by mid-2011.
That document was delivered to NASA and widely circulated within the
astronomical community. In late 2011 the Astrophysics Division augmented its
original charge, asking for two design reference missions. The first of these,
DRM1, was to be a finalized version of the interim DRM, reducing overall
mission costs where possible. The second of these, DRM2, was to identify and
eliminate capabilities that overlapped with those of NASA's James Webb Space
Telescope (henceforth JWST), ESA's Euclid mission, and the NSF's ground-based
Large Synoptic Survey Telescope (henceforth LSST), and again to reduce overall
mission cost, while staying faithful to NWNH. This report presents both DRM1
and DRM2.Comment: 102 pages, 57 figures, 17 table
Default from tuberculosis treatment in Tashkent, Uzbekistan; Who are these defaulters and why do they default?
<p>Abstract</p> <p>Background</p> <p>In Tashkent (Uzbekistan), TB treatment is provided in accordance with the DOTS strategy. Of 1087 pulmonary TB patients started on treatment in 2005, 228 (21%) defaulted. This study investigates who the defaulters in Tashkent are, when they default and why they default.</p> <p>Methods</p> <p>We reviewed the records of 126 defaulters (cases) and 132 controls and collected information on time of default, demographic factors, social factors, potential risk factors for default, characteristics of treatment and recorded reasons for default.</p> <p>Results</p> <p>Unemployment, being a pensioner, alcoholism and homelessness were associated with default. Patients defaulted mostly during the intensive phase, while they were hospitalized (61%), or just before they were to start the continuation phase (26%). Reasons for default listed in the records were various, 'Refusal of further treatment' (27%) and 'Violation of hospital rules' (18%) were most frequently recorded. One third of the recorded defaulters did not really default but continued treatment under 'non-DOTS' conditions.</p> <p>Conclusion</p> <p>Whereas patient factors such as unemployment, being a pensioner, alcoholism and homelessness play a role, there are also system factors that need to be addressed to reduce default. Such system factors include the obligatory admission in TB hospitals and the inadequately organized transition from hospitalized to ambulatory treatment.</p
The state of the Martian climate
60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes
Informing HIV prevention efforts targeting Liberian youth: a study using the PLACE method in Liberia
BACKGROUND: Preventing HIV infection among young people is a priority for the Liberian government. Data on the young people in Liberia are scarce but needed to guide HIV programming efforts. METHODS: We used the Priorities for Local AIDS Control Efforts (PLACE) method to gather information on risk behaviors that young people (ages 14 to 24) engage in or are exposed to that increase their vulnerability for HIV infection. Community informants identified 240 unique venues of which 150 were visited and verified by research staff. 89 of the 150 venues comprised our sampling frame and 571 females and 548 males were interviewed in 50 venues using a behavioral survey. RESULTS: Ninety-one percent of females and 86% of males reported being sexually active. 56% of females and 47% of males reported they initiated sexual activity before the age of 15. Among the sexually active females, 71% reported they had received money or a gift for sex and 56% of males reported they had given money or goods for sex. 20% of females and 6% males reported that their first sexual encounter was forced and 15% of females and 6% of males reported they had been forced to have sex in the past year. Multiple partnerships were common among both sexes with 81% females and 76% males reporting one or more sex partners in the past four weeks. Less than 1% reported having experiences with injecting drugs and only 1% of males reporting have sex with men. While knowledge of HIV/AIDS was high, prevention behaviors including HIV testing and condom use were low. CONCLUSION: Youth-focused HIV efforts in Liberia need to address transactional sex and multiple and concurrent partnerships. HIV prevention interventions should include efforts to meet the economic needs of youth
Transient Astrophysics Probe: White Paper
The Transient Astrophysics Probe (TAP) is a wide-field multi-wavelength transient mission proposed for flight starting in the late 2020s. The mission instruments include unique ``Lobster-eye'' imaging soft X-ray optics that allow an approximately 1600-degrees-squared Field of View (FoV); a high sensitivity, 1-degree-squared FoV soft X-ray telescope; a 1-degree-squared FoV Infrared telescope with bandpass 0.6 to 3 microns; and a set of 8 NaI gamma-ray detectors. TAP's most exciting capability will be the observation of tens per year of X-ray and Infrared counterparts of gravitational waves (GWs) involving stellar-mass black holes and neutron stars detected by LIGO (Laser Interferometer Gravitational-Wave Observatory ) / Virgo / KAGRA (Kamioka (Japan) Gravitational Wave Detector) / LIGO-India, and possibly several per year X-ray counterparts of GWs from supermassive black holes, detected by LISA (Laser Interferometer Space Antenna) and Pulsar Timing Arrays. TAP will also discover hundreds of X-ray transients related to compact objects, including tidal disruption events, supernova shock breakouts, and Gamma-Ray Bursts from the epoch of reionization
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