A
bstract
Excellent energy resolution is one of the primary advantages of electroluminescent high-pressure xenon TPCs. These detectors are promising tools in searching for rare physics events, such ...as neutrinoless double-beta decay (
ββ
0
ν
), which require precise energy measurements. Using the NEXT-White detector, developed by the NEXT (Neutrino Experiment with a Xenon TPC) collaboration, we show for the first time that an energy resolution of 1% FWHM can be achieved at 2.6 MeV, establishing the present technology as the one with the best energy resolution of all xenon detectors for
ββ
0
ν
searches.
Objective
To assess the prevalence of the frailty syndrome and its associated variables among the older adult population in the province of Toledo (Spain).
Methods
Data were taken from the Toledo ...Study for Healthy Aging, a population-based study conducted on 2,488 individuals aged 65 years and older. Study participants were selected by a two-stage random sampling from the municipal census of Toledo, covering both institutionalized and community dwelling persons from rural and urban settings. Data were collected from 2006 to 2009, and included information on social support, activities of daily living, comorbidity, physical activity, quality of life, depressive symptoms, and cognitive function. In addition, a nurse collected anthropometric data, conducted tests of physical performance (walk speed, upper and lower extremities strength, and the stand-and-sit from a chair test) and obtained a blood sample. The diagnosis of the frailty syndrome was based on the Fried criteria (weakness, low speed, low physical activity, exhaustion, and weight loss).
Results
In total, 41.8% (95% confidence interval CI 39.4–44.2%) of the study participants were prefrail, and 8.4% (95% CI 7.1–9.8%) were frail. There were no differences in the prevalence of frailty by sex, level of education, occupation, marital status, or place of residence. The frequency of the frailty syndrome increased with age, and was higher in those with disability, depression, hip fracture and other comorbidity, such as cardiovascular disease and disorders of the central nervous system.
Conclusions
The prevalence of the frailty syndrome in older Spanish adults is high and similar to that reported in other populations in the Mediterranean basin.
Noble element time projection chambers are a leading technology for rare event detection in physics, such as for dark matter and neutrinoless double beta decay searches. Time projection chambers ...typically assign event position in the drift direction using the relative timing of prompt scintillation and delayed charge collection signals, allowing for reconstruction of an absolute position in the drift direction. In this paper, alternate methods for assigning event drift distance via quantification of electron diffusion in a pure high pressure xenon gas time projection chamber are explored. Data from the NEXT-White detector demonstrate the ability to achieve good position assignment accuracy for both high- and low-energy events. Using point-like energy deposits from
83
m
Kr calibration electron captures (
E
∼
45
keV), the position of origin of low-energy events is determined to 2 cm precision with bias
<
1
mm. A convolutional neural network approach is then used to quantify diffusion for longer tracks (
E
≥
1.5
MeV), from radiogenic electrons, yielding a precision of 3 cm on the event barycenter. The precision achieved with these methods indicates the feasibility energy calibrations of better than 1% FWHM at Q
β
β
in pure xenon, as well as the potential for event fiducialization in large future detectors using an alternate method that does not rely on primary scintillation.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A
bstract
Convolutional neural networks (CNNs) are widely used state-of-the-art computer vision tools that are becoming increasingly popular in high-energy physics. In this paper, we attempt to ...understand the potential of CNNs for event classification in the NEXT experiment, which will search for neutrinoless double-beta decay in
136
Xe. To do so, we demonstrate the usage of CNNs for the identification of electron-positron pair production events, which exhibit a topology similar to that of a neutrinoless double-beta decay event. These events were produced in the NEXT-White high-pressure xenon TPC using 2.6 MeV gamma rays from a
228
Th calibration source. We train a network on Monte Carlo-simulated events and show that, by applying on-the-fly data augmentation, the network can be made robust against differences between simulation and data. The use of CNNs offers significant improvement in signal efficiency and background rejection when compared to previous non-CNN-based analyses.
Observations by several cameras on the Perseverance rover showed a 22° scattering halo
around the Sun over several hours during northern midsummer (solar longitude 142°). Such a halo has not ...previously been seen beyond Earth. The halo occurred during the aphelion cloud belt season and the cloudiest time yet observed from the Perseverance site. The halo required crystalline water-ice cloud particles in the form of hexagonal columns large enough for refraction to be significant, at least 11 μm in diameter and length. From a possible 40-50 km altitude, and over the 3.3-hour duration of the halo, particles could have fallen 3-12 km, causing downward transport of water and dust. Halo-forming clouds are likely rare due to the high supersaturation of water that is required but may be more common in northern subtropical regions during northern midsummer.
The extent to which pre-Columbian societies altered Amazonian landscapes is hotly debated. We performed a basin-wide analysis of pre-Columbian impacts on Amazonian forests by overlaying known ...archaeological sites in Amazonia with the distributions and abundances of 85 woody species domesticated by pre-Columbian peoples. Domesticated species are five times more likely than nondomesticated species to be hyperdominant. Across the basin, the relative abundance and richness of domesticated species increase in forests on and around archaeological sites. In southwestern and eastern Amazonia, distance to archaeological sites strongly influences the relative abundance and richness of domesticated species. Our analyses indicate that modern tree communities in Amazonia are structured to an important extent by a long history of plant domestication by Amazonian peoples.
Rovers and landers on Mars have experienced local, regional, and planetary‐scale dust storms. However, in situ documentation of active lifting within storms has remained elusive. Over 5–11 January ...2022 (LS 153°–156°), a dust storm passed over the Perseverance rover site. Peak visible optical depth was ∼2, and visibility across the crater was briefly reduced. Pressure amplitudes and temperatures responded to the storm. Winds up to 20 m s−1 rotated around the site before the wind sensor was damaged. The rover imaged 21 dust‐lifting events—gusts and dust devils—in one 25‐min period, and at least three events mobilized sediment near the rover. Rover tracks and drill cuttings were extensively modified, and debris was moved onto the rover deck. Migration of small ripples was seen, but there was no large‐scale change in undisturbed areas. This work presents an overview of observations and initial results from the study of the storm.
Plain Language Summary
Mars commonly has local and regional dust storms, some of which grow into global dust storms. Until now, no lander or rover on Mars has observed the meteorology and processes within an active lifting storm center. The Perseverance rover experienced a large regional storm in Jezero crater over six sols (Martian days) in January 2022. It documented active dust lifting and winds reshaping the Martian sediment. Winds increased as the storm approached but were only directly monitored until the afternoon of the first sol, when the wind sensor failed during high winds. Winds, even after the loss of the wind sensor, were powerful enough to blow sand and lift dust around the rover. Rover imaging showed 21 dust devils and other dust lifting events near noon of the first sol. Images of the rover and terrain showed that there were several incidents of sediment mobilization immediately around the rover. Rover tracks were erased or heavily modified, cuttings from a recent drilling were removed, and sediment was deposited across the rover's deck. The changes wrought by the storm were concentrated on areas where the rover had previously modified the terrain, except for sand motion including the migration of small sand ripples.
Key Points
The Perseverance rover documented the meteorology and effects of a dust storm as it passed over Jezero crater, Mars
The storm brought damaging winds and wide‐spread dust lifting, while modifying the pressure amplitudes and thermal cycle at the site
Winds extensively modified previously disturbed areas, while sand motion and small‐scale ripple migration occurred all around the rover
We analyse the rotation curves and gravitational stability of a sample of six bulgeless galaxies for which detailed images reveal no evidence for strong bars. We explore two scenarios: Newtonian dark ...matter models and MOdified Newtonian Dynamics (MOND). By adjusting the stellar mass-to-light ratio, dark matter models can match simultaneously both the rotation curve and bar-stability requirements in these galaxies. To be consistent with stability constraints, in two of these galaxies, the stellar mass-to-light ratio is a factor of ∼1.5–2 lower than the values suggested from galaxy colours. In contrast, MOND fits to the rotation curves are poor in three galaxies, perhaps because the gas tracer contains non-circular motions. The bar stability analysis provides a new observational test to MOND. We find that most of the galaxies under study require abnormally high levels of random stellar motions to be bar stable in MOND. In particular, for the only galaxy in the sample for which the line-of-sight stellar velocity dispersion has been measured (NGC 6503), the observed velocity dispersion is not consistent with MOND predictions because it is far below the required value to guarantee bar stability. Precise measurements of mass-weighted velocity dispersions in (unbarred and bulgeless) spiral galaxies are crucial to test the consistency of MOND.
This paper presents a practical implementation of a photovoltaic I-V curves and maximum power point estimation algorithm (IVMPPE). The IVMPPE estimates the I-V curve and sets the operation of the ...solar panels at a voltage that extracts the maximum available power without tracking. The operation is based on solving the parameters of the solar array equivalent electrical model, in real time, only with the measurements of six voltage and current coordinates near the operating point. Moreover, the strategy for selecting the measured points and the discard procedures for incorrect estimated curves are also detailed. To validate the IVMPPE, it has been tested under different operating conditions, and its accuracy has been compared with the classical perturb and observe (P&O) technique. The distinguishing feature of the IVMPPE is that complete I-V model is obtained, not only the MPP, enlarging the capabilities to other fields, e.g., real-time monitoring and prediction.
One of the most important models to predict the electrical behavior of a photovoltaic (PV) module is the so-called single-diode model. This model is derived from the electrical equivalent circuit ...formed by a current source in parallel with one diode, a shunt resistor and a series resistor. The model equation depends on five parameters, if these parameters are obtained, it has been tested that this model fits accurately the real behavior of the PV module under a minimum of illumination. Nevertheless, the extraction of the parameters is quite difficult since none of the variables in the model equation can be expressed in explicit form. This fact also implies the difficulty of knowing the real properties of the current as an implicit function of the voltage in this model. Knowing these properties deeply will involve a more suitable use of the model and better understanding of the behavior of the photovoltaic module. The first goal of this paper is the rigorous mathematical study of the model. In particular, it is demonstrated that the model equation actually defines the current as an implicit function of the voltage which is indefinitely differentiable along the real line. We will provide the most significant geometric properties of the current function by means of the study of the first and the second derivatives functions which are also implicitly given. The second goal of the paper is, given real data of voltage and current measured from a PV module, to show how the parameters of the model equation can be extracted in a very simple way, giving rise to an estimated curve which fits accurately the real one. The proposed new analytical method is as good, for instance, as the well-known analytical five point method but significantly simpler.
•We prove that the single-diode model I–V curve is strictly decreasing and concave.•We demonstrate that the model I–V curve has an oblique asymptote at left-hand.•We provide a new analytical method based on the oblique asymptote.•The oblique asymptote method extracts easily the single-diode model parameters.•Our method provides good results comparable with the Analytical Five Point Method.
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