629 research outputs found
Research Note: Bayesian Record Linkage with Application to Chinese Immigrants in Raleigh-Durham (ChIRDU) Study
Many population surveys do not provide information on respondents'
residential addresses, instead offering coarse geographies like zip code or
higher aggregations. However, fine resolution geography can be beneficial for
characterizing neighborhoods, especially for relatively rare populations such
as immigrants. One way to obtain such information is to link survey records to
records in auxiliary databases that include residential addresses by matching
on variables common to both files. In this research note, we present an
approach based on probabilistic record linkage that enables matching survey
participants in the Chinese Immigrants in Raleigh-Durham (ChIRDU) Study to
records from InfoUSA, an information provider of residential records. The two
files use different Chinese name romanization practices, which we address
through a novel and generalizable strategy for constructing records' pairwise
comparison vectors for romanized names. Using a fully Bayesian record linkage
model, we characterize the geospatial distribution of Chinese immigrants in the
Raleigh-Durham area
In-situ strain tuning of the Dirac surface states in Bi2Se3 films
Elastic strain has the potential for a controlled manipulation of the band
gap and spin-polarized Dirac states of topological materials, which can lead to
pseudo-magnetic-field effects, helical flat bands and topological phase
transitions. However, practical realization of these exotic phenomena is
challenging and yet to be achieved. Here, we show that the Dirac surface states
of the topological insulator Bi2Se3 can be reversibly tuned by an externally
applied elastic strain. Performing in-situ x-ray diffraction and in-situ
angle-resolved photoemission spectroscopy measurements during tensile testing
of epitaxial Bi2Se3 films bonded onto a flexible substrate, we demonstrate
elastic strains of up to 2.1% and quantify the resulting reversible changes in
the topological surface state. Our study establishes the functional
relationship between the lattice and electronic structures of Bi2Se3 and, more
generally, demonstrates a new route toward momentum-resolved mapping of
strain-induced band structure changes
A world of cobenefits : solving the global nitrogen challenge
Houlton, Benjamin Z. University of California. John Muir Institute of the Environment. Davis, CA, USA.Houlton, Benjamin Z. University of California. Department of Land, Air and Water Resources. Davis, CA, USA.Almaraz, Maya. University of California. Department of Land, Air and Water Resources. Davis, CA, USA.Aneja, Viney. North Carolina State University at Raleigh. Department of Marine, Earth, and Atmospheric Sciences. Raleigh, NC, USA.Austin, Amy T. Universidad de Buenos Aires. Facultad de AgronomĂa. Instituto de Investigaciones FisiolĂłgicas y EcolĂłgicas Vinculadas a la Agricultura (IFEVA). Buenos Aires, Argentina.Austin, Amy T. CONICET â Universidad de Buenos Aires. Instituto de Investigaciones FisiolĂłgicas y EcolĂłgicas Vinculadas a la Agricultura (IFEVA). Buenos Aires, Argentina.Bai, Edith. Chinese Academy of Sciences. Institute of Applied Ecology. CAS Key Laboratory of Forest Ecology and Management. Shenyang, China.Bai, Edith. Northeast Normal University. School of Geographical Sciences. Changchun, China.Cassman, Kenneth. University of Nebraska â Lincoln. Department of Agronomy and Horticulture. Lincoln. NE, USA.Compton, Jana E. Environmental Protection Agency. Western Ecology Division. Washington, DC, USA.Davidson, Eric A. University of Maryland Center for Environmental Science. Appalachian Laboratory. Cambridge, MD, USA.865-872Nitrogen is a critical component of the economy, food security, and planetary health. Many of the world's sustainability targets hinge on global nitrogen solutions, which, in turn, contribute lasting benefits for (i) world hunger; (ii) soil, air, and water quality; (iii) climate change mitigation; and (iv) biodiversity conservation. Balancing the projected rise in agricultural nitrogen demands while achieving these 21st century ideals will require policies to coordinate solutions among technologies, consumer choice, and socioeconomic transformation
Toward automated irrigation management with integrated crop water stress index and spatial soil water balance
Decision support systems intended for precision irrigation aim at reducing irrigation applications while optimizing crop yield to achieve maximum crop water productivity (CWP). These systems incorporate on-site sensor data, remote sensing inputs, and advanced algorithms with spatial and temporal characteristics to compute precise crop water needs. The availability of variable rate irrigation (VRI) systems enables irrigation applications at a sub-field scale. The combination of an appropriate VRI system along with a precise decision support system would be ideal for improved CWP. The objective of this study was to compare and evaluate two decision support systems in terms of seasonal applied irrigation, crop yield, and CWP. This study implemented the Spatial EvapoTranspiration Modeling Interface (SETMI) model and the Irrigation Scheduling Supervisory Control and Data Acquisition (ISSCADA) system for management of a center pivot irrigation system in a 58-ha maize-soybean field during the 2020 and 2021 growing seasons. The irrigation scheduling methods included: ISSCADA plant feedback, ISSCADA hybrid, common practice, and SETMI. These methods were applied at irrigation levels of 0, 50, 100, and 150% of the full irrigation prescribed by the respective irrigation scheduling method. Data from infrared thermometers (IRTs), soil water sensors, weather stations, and satellites were used in the irrigation methods. Mean seasonal irrigation prescribed was different among the irrigation levels and methods for the 2 years. The ISSCADA plant feedback prescribed the least irrigation among the methods for majority of the cases. The common practice prescribed the largest seasonal irrigation depth among the methods for three crop-year cases. The maize yield in rainfed was found to be significantly lower than the irrigated levels in 2020 since 2020 was a dry year. No significant differences were observed in crop yield among the different irrigation methods for both years. The CWP among the different irrigation methods ranged between 2.72 and 3.15 kg mâ3 for 2020 maize, 1.03 and 1.13 kg mâ3 for 2020 soybean, 3.57 and 4.24 kg mâ3 for 2021 maize, and 1.19 and 1.48 kg mâ3 for 2021 soybean. Deficit level (50%) had the largest irrigation water productivity in all crop-year cases in this study. The ISSCADA and SETMI systems were found to reduce irrigation applications as compared to the common practice while maintaining crop yield. This study was the first to implement the newly developed integrated crop water stress index (iCWSI) thresholds and the ISSCADA system for site-specific irrigation of maize and soybean in Nebraska
Toward automated irrigation management with integrated crop water stress index and spatial soil water balance
Decision support systems intended for precision irrigation aim at reducing irrigation applications while optimizing crop yield to achieve maximum crop water productivity (CWP). These systems incorporate on-site sensor data, remote sensing inputs, and advanced algorithms with spatial and temporal characteristics to compute precise crop water needs. The availability of variable rate irrigation (VRI) systems enables irrigation applications at a sub-field scale. The combination of an appropriate VRI system along with a precise decision support system would be ideal for improved CWP. The objective of this study was to compare and evaluate two decision support systems in terms of seasonal applied irrigation, crop yield, and CWP. This study implemented the Spatial EvapoTranspiration Modeling Interface (SETMI) model and the Irrigation Scheduling Supervisory Control and Data Acquisition (ISSCADA) system for management of a center pivot irrigation system in a 58-ha maize-soybean field during the 2020 and 2021 growing seasons. The irrigation scheduling methods included: ISSCADA plant feedback, ISSCADA hybrid, common practice, and SETMI. These methods were applied at irrigation levels of 0, 50, 100, and 150% of the full irrigation prescribed by the respective irrigation scheduling method. Data from infrared thermometers (IRTs), soil water sensors, weather stations, and satellites were used in the irrigation methods. Mean seasonal irrigation prescribed was different among the irrigation levels and methods for the 2 years. The ISSCADA plant feedback prescribed the least irrigation among the methods for majority of the cases. The common practice prescribed the largest seasonal irrigation depth among the methods for three crop-year cases. The maize yield in rainfed was found to be significantly lower than the irrigated levels in 2020 since 2020 was a dry year. No significant differences were observed in crop yield among the different irrigation methods for both years. The CWP among the different irrigation methods ranged between 2.72 and 3.15 kg mâ3 for 2020 maize, 1.03 and 1.13 kg mâ3 for 2020 soybean, 3.57 and 4.24 kg mâ3 for 2021 maize, and 1.19 and 1.48 kg mâ3 for 2021 soybean. Deficit level (50%) had the largest irrigation water productivity in all crop-year cases in this study. The ISSCADA and SETMI systems were found to reduce irrigation applications as compared to the common practice while maintaining crop yield. This study was the first to implement the newly developed integrated crop water stress index (iCWSI) thresholds and the ISSCADA system for site-specific irrigation of maize and soybean in Nebraska
Dust-Obscured Star-Formation in Intermediate Redshift Galaxy Clusters
We present Spitzer MIPS 24-micron observations of 16 0.4<z<0.8 galaxy
clusters drawn from the ESO Distant Cluster Survey (EDisCS). This is the first
large 24-micron survey of clusters at intermediate redshift. The depth of our
imaging corresponds to a total IR luminosity of 8x10^10 Lsun, just below the
luminosity of luminous infrared galaxies (LIRGs), and 6^{+1}_{-1}% of M_V < -19
cluster members show 24-micron emission at or above this level. We compare with
a large sample of coeval field galaxies and find that while the fraction of
cluster LIRGs lies significantly below that of the field, the IR luminosities
of the field and cluster galaxies are consistent. However, the stellar masses
of the EDisCS LIRGs are systematically higher than those of the field LIRGs. A
comparison with optical data reveals that ~80% of cluster LIRGs are blue and
the remaining 20% lie on the red sequence. Of LIRGs with optical spectra,
88^{+4}_{-5}% show [O II] emission with EW([O II])>5A, and ~75% exhibit optical
signatures of dusty starbursts. On average, the fraction of cluster LIRGs
increases with projected cluster-centric radius but remains systematically
lower than the field fraction over the area probed (< 1.5xR200). The amount of
obscured star formation declines significantly over the 2.4 Gyr interval
spanned by the EDisCS sample, and the rate of decline is the same for the
cluster and field populations. Our results are consistent with an exponentially
declining LIRG fraction, with the decline in the field delayed by ~1 Gyr
relative to the clusters.Comment: 15 pages, 9 figure
Recommended from our members
Fluoroalkyl and Alkyl Chains Have Similar Hydrophobicities in Binding to the âHydrophobic Wallâ of Carbonic Anhydrase
This paper describes the performance of junctions based on self-assembled monolayers (SAMs) as the functional element of a half-wave rectifier (a simple circuit that converts, or rectifies, an alternating current (AC) signal to a direct current (DC) signal). Junctions with SAMs of 11-(ferrocenyl)-1-undecanethiol or 11-(biferrocenyl)-1-undecanethiol on ultraflat, template-stripped Ag (AgTS) bottom electrodes, and contacted by top electrodes of eutectic indiumâgallium (EGaIn), rectified AC signals, while similar junctions based on SAMs of 1-undecanethiolâSAMs lacking the ferrocenyl terminal groupâdid not. SAMs in these AC circuits (operating at 50 Hz) remain stable over a larger window of applied bias than in DC circuits. AC measurements, therefore, can investigate charge transport in SAM-based junctions at magnitudes of bias inaccessible to DC measurements. For junctions with SAMs of alkanethiols, combining the results from AC and DC measurements identifies two regimes of bias with different mechanisms of charge transport: (i) low bias (|V| 1.3 V), at which FowlerâNordheim (FN) tunneling dominates. For junctions with SAMs terminated by Fc moieties, the transition to FN tunneling occurs at |V| â 2.0 V. Furthermore, at sufficient forward bias (V > 0.5 V), hopping makes a significant contribution to charge transport and occurs in series with direct tunneling (V 2.0 V) until FN tunneling activates (V 2.0 V). Thus, for Fc-terminated SAMs at forward bias, three regimes are apparent: (i) direct tunneling (V = 0â0.5 V), (ii) hopping plus direct tunneling (V â 0.5â2.0 V), and (iii) FN tunneling (V 2.0 V). Since hopping does not occur at reverse bias, only two regimes are present over the measured range of reverse bias. This difference in the mechanisms of charge transport at forward and reverse bias for junctions with Fc moieties resulted in large rectification ratios (R > 100) and enabled half-wave rectification.Chemistry and Chemical Biolog
Interface Controlled Thermal Resistances of Ultra-Thin Chalcogenide-Based Phase Change Memory Devices
Phase change memory (PCM) is a rapidly growing technology that not only offers advancements in storage-class memories but also enables in-memory data processing to overcome the von Neumann bottleneck. In PCMs, data storage is driven by thermal excitation. However, there is limited research regarding PCM thermal properties at length scales close to the memory cell dimensions. Our work presents a new paradigm to manage thermal transport in memory cells by manipulating the interfacial thermal resistance between the phase change unit and the electrodes without incorporating additional insulating layers. Experimental measurements show a substantial change in interfacial thermal resistance as GST transitions from cubic to hexagonal crystal structure, resulting in a factor of 4 reduction in the effective thermal conductivity. Simulations reveal that interfacial resistance between PCM and its adjacent layer can reduce the reset current for 20 and 120 nm diameter devices by up toâ~â40% andâ~â50%, respectively. These thermal insights present a new opportunity to reduce power and operating currents in PCMs
Experimental infection of conventional nursing pigs and their dams with \u3ci\u3ePorcine deltacoronavirus\u3c/i\u3e
Porcine deltacoronavirus (PDCoV) is a newly identified virus that has been detected in swine herds of North America associated with enteric disease. The aim of this study was to demonstrate the pathogenicity, course of infection, virus kinetics, and aerosol transmission of PDCoV using 87 conventional piglets and their 9 dams, including aerosol and contact controls to emulate field conditions. Piglets 2â4 days of age and their dams were administered an oronasal PDCoV inoculum with a quantitative real-time reverse transcription (qRT)-PCR quantification cycle (Cq) value of 22 that was generated from a field sample having 100% nucleotide identity to USA/Illinois121/2014 determined by metagenomic sequencing and testing negative for other enteric disease agents using standard assays. Serial samples of blood, serum, oral fluids, nasal and fecal swabs, and tissues from sequential autopsy, conducted daily on days 1â8 and regular intervals thereafter, were collected throughout the 42-day study for qRT-PCR, histopathology, and immunohistochemistry. Diarrhea developed in all inoculated and contact control pigs, including dams, by 2 days post-inoculation (dpi) and in aerosol control pigs and dams by 3â4 dpi, with resolution occurring by 12 dpi. Mild to severe atrophic enteritis with PDCoV antigen staining was observed in the small intestine of affected piglets from 2 to 8 dpi. Mesenteric lymph node and small intestine were the primary sites of antigen detection by immunohistochemistry, and virus RNA was detected in these tissues to the end of the study. Virus RNA was detectable in piglet fecal swabs to 21 dpi, and dams to 14â35 dpi
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