322 research outputs found
Effect of Phosphorus Nutrition on Growth and Physiology of Cotton Under Ambient and Elevated Carbon Dioxide
Phosphorous deficiency in soil limits crop growth and productivity in the majority of arable lands worldwide and may moderate the growth enhancement effect of rising atmospheric carbon dioxide (CO2) concentration. To evaluate the interactive effect of these two factors on cotton (Gossypium hirsutum) growth and physiology, plants were grown in controlled environment growth chambers with three levels of phosphate (Pi) supply (0.20, 0.05 and 0.01 mM) under ambient and elevated (400 and 800 μmol mol‒1, respectively) CO2. Phosphate stress caused stunted growth and resulted in early leaf senescence with severely decreased leaf area and photosynthesis. Phosphate stress led to over 77 % reduction in total biomass across CO2 levels. There was a below-ground (roots) shift in biomass partitioning under Pi deficiency. While tissue phosphorus (P) decreased, tissue nitrogen (N) content tended to increase under Pi deficiency. The CO2 × Pi interactions were significant on leaf area, photosynthesis and biomass accumulation. The stimulatory effect of elevated CO2 on growth and photosynthesis was reduced or highly depressed suggesting an increased sensitivity of cotton to Pi deficiency under elevated CO2. Although, tissue P and stomatal conductance were lower at elevated CO2, these did not appear to be the main causes of cotton unresponsiveness to elevated CO2 under severe Pi-stress. The alteration in the uptake and utilization of N was suggested due to a consistent reduction (18–21 %) in the cotton plant tissue N content under elevated CO2
AGN Populations in Large Volume X-ray Surveys: Photometric Redshifts and Population Types found in the Stripe 82X Survey
Multi-wavelength surveys covering large sky volumes are necessary to obtain
an accurate census of rare objects such as high luminosity and/or high redshift
active galactic nuclei (AGN). Stripe 82X is a 31.3 deg X-ray survey with
and -Newton observations overlapping the legacy Sloan Digital
Sky Survey (SDSS) Stripe 82 field, which has a rich investment of
multi-wavelength coverage from the ultraviolet to the radio. The wide-area
nature of this survey presents new challenges for photometric redshifts for AGN
compared to previous work on narrow-deep fields because it probes different
populations of objects that need to be identified and represented in the
library of templates. Here we present an updated X-ray plus multi-wavelength
matched catalog, including counterparts, and estimated photometric
redshifts for 5961 (96% of a total of 6181) X-ray sources, which have a
normalized median absolute deviation, = 0.06 and an outlier
fraction, = 13.7%. The populations found in this survey, and the
template libraries used for photometric redshifts, provide important guiding
principles for upcoming large-area surveys such as and 3 (in
X-ray) and the Large Synoptic Survey Telescope (LSST; optical).Comment: Accepted for publication by The Astrophysical Journal (33 pages, 20
figures, 13 tables). Final catalog of counterparts and photo-z supplementing
the paper available here:
http://stripe82x.com/docs/stripe82x-photometric-redshifts-and-multiwavelength-data-catalog
Sensitive Chandra coverage of a representative sample of weak-line quasars::revealing the full range of X-ray properties
We present deeper Chandra observations for weak-line quasars (WLQs) in a
representative sample that previously had limited X-ray constraints, and
perform X-ray photometric analyses to reveal the full range of X-ray properties
of WLQs. Only 5 of the 32 WLQs included in this representative sample remain
X-ray undetected after these observations, and a stacking analysis shows that
these 5 have an average X-ray weakness factor of > 85. One of the WLQs in the
sample that was known to have extreme X-ray variability, SDSS J1539+3954,
exhibited dramatic X-ray variability again: it changed from an X-ray normal
state to an X-ray weak state within ~ 3 months in the rest frame. This short
timescale for an X-ray flux variation by a factor of 9 further
supports the thick disk and outflow (TDO) model proposed to explain the X-ray
and multiwavelength properties of WLQs. The overall distribution of the
X-ray-to-optical properties of WLQs suggests that the TDO has an average
covering factor of the X-ray emitting region of ~ 0.5, and the column density
of the TDO can range from to
, which leads to different levels of
absorption and Compton reflection (and/or scattering) among WLQs.Comment: 16 pages, 10 figures. Accepted for publication in MNRA
Determination of composition and structure of spongy bone tissue in human head of femur by Raman spectral mapping
Biomechanical properties of bone depend on the composition and organization of collagen fibers. In this study, Raman microspectroscopy was employed to determine the content of mineral and organic constituents and orientation of collagen fibers in spongy bone in the human head of femur at the microstructural level. Changes in composition and structure of trabecula were illustrated using Raman spectral mapping. The polarized Raman spectra permit separate analysis of local variations in orientation and composition. The ratios of ν2PO43−/Amide III, ν4PO43−/Amide III and ν1CO32−/ν2PO43− are used to describe relative amounts of spongy bone components. The ν1PO43−/Amide I ratio is quite susceptible to orientation effect and brings information on collagen fibers orientation. The results presented illustrate the versatility of the Raman method in the study of bone tissue. The study permits better understanding of bone physiology and evaluation of the biomechanical properties of bone
The ABCD of usability testing
We introduce a methodology for tracking and auditing feedback, errors and suggestions for software packages. This short paper describes how we innovate on the evaluation mechanism, introducing an (Antecedent, Barrier, Consequence and Development) ABCD form, embedded within an eParticipation platform to enable end users to easily report on any usability issues. This methodology will be utilised to improve the STEP cloud eParticipation platform (part of the current STEP Horizon2020 project http://step4youth.eu. The platform is currently being piloted in real life contexts, with the participation of public authorities that are integrating the eParticipation platform into their regular decision-making practices. The project is involving young people, through engagement and motivation strategies and giving them a voice in Environmental decision making at the local level. The pilot evaluation aims to demonstrate how open engagement needs to be embedded within public sector processes and the usability methodology reported here will help to identify the key barriers for wide scale deployment of the platform
Personalized Antihypertensive Treatment Optimization With Smartphone-Enabled Remote Precision Dosing of Amlodipine During the COVID-19 Pandemic (PERSONAL-CovidBP Trial).
BACKGROUND: The objective of the PERSONAL-CovidBP (Personalised Electronic Record Supported Optimisation When Alone for Patients With Hypertension: Pilot Study for Remote Medical Management of Hypertension During the COVID-19 Pandemic) trial was to assess the efficacy and safety of smartphone-enabled remote precision dosing of amlodipine to control blood pressure (BP) in participants with primary hypertension during the COVID-19 pandemic. METHODS AND RESULTS: This was an open-label, remote, dose titration trial using daily home self-monitoring of BP, drug dose, and side effects with linked smartphone app and telemonitoring. Participants aged ≥18 years with uncontrolled hypertension (5-7 day baseline mean ≥135 mm Hg systolic BP or ≥85 mm Hg diastolic BP) received personalized amlodipine dose titration using novel (1, 2, 3, 4, 6, 7, 8, 9 mg) and standard (5 and 10 mg) doses daily over 14 weeks. The primary outcome of the trial was mean change in systolic BP from baseline to end of treatment. A total of 205 participants were enrolled and mean BP fell from 142/87 (systolic BP/diastolic BP) to 131/81 mm Hg (a reduction of 11 (95% CI, 10-12)/7 (95% CI, 6-7) mm Hg, P<0.001). The majority of participants achieved BP control on novel doses (84%); of those participants, 35% were controlled by 1 mg daily. The majority (88%) controlled on novel doses had no peripheral edema. Adherence to BP recording and reported adherence to medication was 84% and 94%, respectively. Patient retention was 96% (196/205). Treatment was well tolerated with no withdrawals from adverse events. CONCLUSIONS: Personalized dose titration with amlodipine was safe, well tolerated, and efficacious in treating primary hypertension. The majority of participants achieved BP control on novel doses, and with personalization of dose there were no trial discontinuations due to drug intolerance. App-assisted remote clinician dose titration may better balance BP control and adverse effects and help optimize long-term care. REGISTRATION: URL: clinicaltrials.gov. Identifier: NCT04559074
Radiation hardness qualification of PbWO4 scintillation crystals for the CMS Electromagnetic Calorimeter
This is the Pre-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2010 IOPEnsuring the radiation hardness of PbWO4 crystals was one of the main priorities during the construction of the electromagnetic calorimeter of the CMS experiment at CERN. The production on an industrial scale of radiation hard crystals and their certification over a period of several years represented a difficult challenge both for CMS and for the crystal suppliers. The present article reviews the related scientific and technological problems encountered
Intercalibration of the barrel electromagnetic calorimeter of the CMS experiment at start-up
Calibration of the relative response of the individual channels of the barrel electromagnetic calorimeter of the CMS detector was accomplished, before installation, with cosmic ray muons and test beams. One fourth of the calorimeter was exposed to a beam of high energy electrons and the relative calibration of the channels, the intercalibration, was found to be reproducible to a precision of about 0.3%. Additionally, data were collected with cosmic rays for the entire ECAL barrel during the commissioning phase. By comparing the intercalibration constants obtained with the electron beam data with those from the cosmic ray data, it is demonstrated that the latter provide an intercalibration precision of 1.5% over most of the barrel ECAL. The best intercalibration precision is expected to come from the analysis of events collected in situ during the LHC operation. Using data collected with both electrons and pion beams, several aspects of the intercalibration procedures based on electrons or neutral pions were investigated
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