2,553 research outputs found
Economics of nitrogen and integrated weed management in dry seeded rice
Dry-seeded rice (DSR) is an emerging production technology in many Asian countries, whose profitability is higher than puddled transplanted rice. However, weed infestations are severe in the DSR. To increase the competitiveness with weeds and achieve the yield potential of rice, weed management in DSR needs an integration of herbicides and higher nitrogen (N) fertilizer rates. Field experiments were conducted in the aman (wet season) 2012 and 2013 in Bangladesh to evaluate the effect of N rates (0, 80, 120, and 160 kg ha) and weed control methods [one hand weeding (HW); pendimethalin 1000 g ai ha followed by (fb) ethoxysulfuron 20 g ai ha; pendimethalin fb ethoxysulfuron fb one HW; and weed-free] on weed growth and crop yield in DSR. The experiment was arranged in a split-plot design with three replications. The highest grain yield (5.3 to 5.5 t ha) was recorded in the season-long manual weed free treatment when N rate was160 kg ha; however, because of the high cost of labor, this method was not profitable. The use of pendimethalin fb ethoxysulfuron fb one HW effectively controlled weeds and produced a similar yield with the weed-free treatment for all levels of N. However, weed management cost was also higher because of the involvement of one HW. Although pendimethalin fb ethoxysulfuron treatment had always lower yielded than the pendimethalin fb ethoxysulfuron fb one HW, grain yield increased and net profit was similar when N rate increased from 120 to 160 kg ha. Considering weed control efficiency, yield, and economics, pendimethalin fb ethoxysulfuron fb one HW with 120 kg N ha may be recommended to growers. However, if laborers are not available for hand weeding, pendimethalin fb ethoxysulfuron with 160 kg N ha is the best option to achieve high yield in DSR
Strongly lensed SNe Ia in the era of LSST: observing cadence for lens discoveries and time-delay measurements
The upcoming Large Synoptic Survey Telescope (LSST) will detect many strongly
lensed Type Ia supernovae (LSNe Ia) for time-delay cosmography. This will
provide an independent and direct way for measuring the Hubble constant ,
which is necessary to address the current tension in between
the local distance ladder and the early Universe measurements. We present a
detailed analysis of different observing strategies for the LSST, and quantify
their impact on time-delay measurement between multiple images of LSNe Ia. For
this, we produced microlensed mock-LSST light curves for which we estimated the
time delay between different images. We find that using only LSST data for
time-delay cosmography is not ideal. Instead, we advocate using LSST as a
discovery machine for LSNe Ia, enabling time delay measurements from follow-up
observations from other instruments in order to increase the number of systems
by a factor of 2 to 16 depending on the observing strategy. Furthermore, we
find that LSST observing strategies, which provide a good sampling frequency
(the mean inter-night gap is around two days) and high cumulative season length
(ten seasons with a season length of around 170 days per season), are favored.
Rolling cadences subdivide the survey and focus on different parts in different
years; these observing strategies trade the number of seasons for better
sampling frequency. In our investigation, this leads to half the number of
systems in comparison to the best observing strategy. Therefore rolling
cadences are disfavored because the gain from the increased sampling frequency
cannot compensate for the shortened cumulative season length. We anticipate
that the sample of lensed SNe Ia from our preferred LSST cadence strategies
with rapid follow-up observations would yield an independent percent-level
constraint on .Comment: 25 pages, 22 figures; accepted for publication in A&
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The LSST DESC data challenge 1: Generation and analysis of synthetic images for next-generation surveys
Data Challenge 1 (DC1) is the first synthetic data set produced by the Rubin Observatory Legacy Survey of Space and Time (LSST) Dark Energy Science Collaboration (DESC). DC1 is designed to develop and validate data reduction and analysis and to study the impact of systematic effects that will affect the LSST data set. DC1 is comprised of r-band observations of 40 deg2 to 10 yr LSST depth. We present each stage of the simulation and analysis process: (a) generation, by synthesizing sources from cosmological N-body simulations in individual sensor-visit images with different observing conditions; (b) reduction using a development version of the LSST Science Pipelines; and (c) matching to the input cosmological catalogue for validation and testing. We verify that testable LSST requirements pass within the fidelity of DC1. We establish a selection procedure that produces a sufficiently clean extragalactic sample for clustering analyses and we discuss residual sample contamination, including contributions from inefficiency in star-galaxy separation and imperfect deblending. We compute the galaxy power spectrum on the simulated field and conclude that: (i) survey properties have an impact of 50 per cent of the statistical uncertainty for the scales and models used in DC1; (ii) a selection to eliminate artefacts in the catalogues is necessary to avoid biases in the measured clustering; and (iii) the presence of bright objects has a significant impact (2-6) in the estimated power spectra at small scales (> 1200), highlighting the impact of blending in studies at small angular scales in LSST
Emotional distress, anxiety, and depression in South Asians with long-term conditions: a qualitative systematic review.
BACKGROUND: People with physical-mental comorbidity have a poorer quality of life, worse clinical outcomes, and increased mortality compared with people with physical conditions alone. People of South Asian (SA) origin are the largest minority group in the UK and are more likely to have long-term conditions (LTCs) such as diabetes and heart disease. People of SA origin are less likely to recognise symptoms that may represent mental health problems. AIM: To explore how people of SA origin with LTCs understand, experience, and seek help for emotional distress, depression, and anxiety. DESIGN AND SETTING: Systematic review of qualitative studies exploring emotional distress in people of SA origin with diabetes or coronary heart disease, within primary and community care settings worldwide. METHOD: Comprehensive searches of eight electronic databases from inception to 1 September 2021 were undertaken. Data extracted included study characteristics, and understanding, experience, and help-seeking behaviour for emotional distress. Thematic synthesis was undertaken. The Critical Appraisal Skills Programme (CASP) checklist for qualitative studies was used to assess quality of articles, and Confidence in the Evidence from Reviews of Qualitative Research (GRADE-CERQual) used to determine the overall strength of evidence. RESULTS: Twenty-one studies from 3165 unique citations were included. Three main themes were identified. Understanding of emotional distress: non-medical terminology used, such as 'tension', and a complex relationship between emotional and physical illness. Experiences of emotional distress: multiple forms of inequality, distress at diagnosis of their LTC, cultural factors, and sex differences. Help-seeking behaviour: self-management, support from family, friends, and faith, and inadequate clinical support. CONCLUSION: This review provides a greater understanding of the conceptualisation of emotional distress in the context of LTCs by people of SA origin, to support improvement in its recognition and management
SCREENING OF HERBICIDES FOR WEED MANAGEMENT IN TRANSPLANTED RICE
ABSTRACT (2005) . All of the herbicidal treatments did not differ significantly from hand weeding during both the years for this character. In terms of paddy yield, hand weeding gave the highest grain yield but remained statistically at par with certain herbicides. Welchlore and declore gave lower yield for the year 2004 and 2005, respectively. Control (weedy check) produced the lowest yield during both the years
Design of Multicationic Copper-Bearing Layered Double Hydroxides for Catalytic Application in Biorefinery
Ethanol has been used as a renewable hydrogen-donor in the conversion of a lignin model molecule in subcritical conditions. Noble metal-free porous mixed oxides, obtained by activation of Cu-Ni-Al and Cu-Ni-Fe layered double hydroxide (LDH) precursors, have been used as heterogeneous catalysts for Meerwein-Ponndorf-Verley (MPV) hydrogen transfer and further hydrogenation by ethanol dehydrogenation products. Both the Cu/(Cu+Ni) ratio and the nature of the trivalent cation (Al or Fe) affect the activity of the catalysts, as well as the selectivity towards the different steps of the hydrogenation reactions and the cleavage of lignin-like phenylether bonds. Accounting for the peculiar behaviour of Cu2+ and M(III) cations in the synthesis of LDHs, the coprecipitation of the precursors has been monitored by titration experiments. Structural and textural properties of the catalysts are closely related to the composition of the LDH precursors
Vaccines against toxoplasma gondii : challenges and opportunities
Development of vaccines against Toxoplasma gondii infection in humans is of high priority, given the high burden of disease in some areas of the world like South America, and the lack of effective drugs with few adverse effects. Rodent models have been used in research on vaccines against T. gondii over the past decades. However, regardless of the vaccine construct, the vaccines have not been able to induce protective immunity when the organism is challenged with T. gondii, either directly or via a vector. Only a few live, attenuated T. gondii strains used for immunization have been able to confer protective immunity, which is measured by a lack of tissue cysts after challenge. Furthermore, challenge with low virulence strains, especially strains with genotype II, will probably be insufficient to provide protection against the more virulent T. gondii strains, such as those with genotypes I or II, or those genotypes from South America not belonging to genotype I, II or III. Future studies should use animal models besides rodents, and challenges should be performed with at least one genotype II T. gondii and one of the more virulent genotypes. Endpoints like maternal-foetal transmission and prevention of eye disease are important in addition to the traditional endpoint of survival or reduction in numbers of brain cysts after challenge
Performance of a Large-Area GEM Detector Prototype for the Upgrade of the CMS Muon Endcap System
Gas Electron Multiplier (GEM) technology is being considered for the forward
muon upgrade of the CMS experiment in Phase 2 of the CERN LHC. Its first
implementation is planned for the GE1/1 system in the region of the muon endcap mainly to control muon level-1 trigger rates
after the second long LHC shutdown. A GE1/1 triple-GEM detector is read out by
3,072 radial strips with 455 rad pitch arranged in eight -sectors.
We assembled a full-size GE1/1 prototype of 1m length at Florida Tech and
tested it in 20-120 GeV hadron beams at Fermilab using Ar/CO 70:30 and
the RD51 scalable readout system. Four small GEM detectors with 2-D readout and
an average measured azimuthal resolution of 36 rad provided precise
reference tracks. Construction of this largest GEM detector built to-date is
described. Strip cluster parameters, detection efficiency, and spatial
resolution are studied with position and high voltage scans. The plateau
detection efficiency is [97.1 0.2 (stat)]\%. The azimuthal resolution is
found to be [123.5 1.6 (stat)] rad when operating in the center of
the efficiency plateau and using full pulse height information. The resolution
can be slightly improved by 10 rad when correcting for the bias due
to discrete readout strips. The CMS upgrade design calls for readout
electronics with binary hit output. When strip clusters are formed
correspondingly without charge-weighting and with fixed hit thresholds, a
position resolution of [136.8 2.5 stat] rad is measured, consistent
with the expected resolution of strip-pitch/ = 131.3 rad. Other
-sectors of the detector show similar response and performance.Comment: 8 pages, 32 figures, submitted to Proc. 2014 IEEE Nucl. Sci.
Symposium, Seattle, WA, reference adde
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