The LUX-ZEPLIN experiment is a dark matter detector centered on a dual-phase xenon time projection chamber operating at the Sanford Underground Research Facility in Lead, South Dakota, USA. This ...Letter reports results from LUX-ZEPLIN's first search for weakly interacting massive particles (WIMPs) with an exposure of 60 live days using a fiducial mass of 5.5 t. A profile-likelihood ratio analysis shows the data to be consistent with a background-only hypothesis, setting new limits on spin-independent WIMP-nucleon, spin-dependent WIMP-neutron, and spin-dependent WIMP-proton cross sections for WIMP masses above 9 GeV/c^{2}. The most stringent limit is set for spin-independent scattering at 36 GeV/c^{2}, rejecting cross sections above 9.2×10^{-48} cm at the 90% confidence level.
Purpose
The study’s objective was to develop diagnostic predictive models using data from two commonly used
123
IFP-CIT SPECT assessment methods: region-of-interest (ROI) analysis and whole-brain ...voxel-based analysis.
Methods
We included retrospectively 80 patients with vascular parkinsonism (VP) and 164 patients with Parkinson’s disease (PD) who underwent
123
IFP-CIT SPECT. Nuclear-medicine specialists evaluated the scans and calculated bilateral caudate and putamen
123
IFP-CIT uptake and asymmetry indices using BRASS software. Statistical parametric mapping (SPM) was used to compare the radioligand uptake between the two diseases at the voxel level. Quantitative data from these two methods, together with potential confounding factors for dopamine transporter availability (sex, age, disease duration and severity), were used to build predictive models following a tenfold cross-validation scheme. The performance of logistic regression (LR), linear discriminant analysis and support vector machine (SVM) algorithms for ROI data, and their penalized versions for SPM data (penalized LR, penalized discriminant analysis and SVM), were assessed.
Results
Significant differences were found in the ROI analysis after covariate correction between VP and PD patients in
123
IFP-CIT uptake in the more affected side of the putamen and the ipsilateral caudate. Age, disease duration and severity were also found to be informative in feeding the statistical model. SPM localized significant reductions in
123
IFP-CIT uptake in PD with respect to VP in two specular clusters comprising areas corresponding to the left and right striatum. The diagnostic predictive accuracy of the LR model using ROI data was 90.3 % and of the SVM model using SPM data was 90.4 %.
Conclusion
The predictive models built with ROI data and SPM data from
123
IFP-CIT SPECT provide great discrimination accuracy between VP and PD. External validation of these methods is necessary to confirm their applicability across centres.
The Javalambre-Physics of the Accelerating Universe Astrophysical Survey (J-PAS) is expected to map thousands of square degrees of the northern sky with 56 narrowband filters (spectral resolution of
...R
∼ 60) in the upcoming years. This resolution allows us to study emission line galaxies (ELGs) with a minimum equivalent width of 10 Å in the H
α
emission line for a median signal-to-noise ratio (S/N) of 5. This will make J-PAS a very competitive and unbiased emission line survey compared to spectroscopic or narrowband surveys with fewer filters. The miniJPAS survey covered 1 deg
2
, and it used the same photometric system as J-PAS, but the observations were carried out with the pathfinder J-PAS camera. In this work, we identify and characterize the sample of ELGs from miniJPAS with a redshift lower than 0.35, which is the limit to which the H
α
line can be observed with the J-PAS filter system. Using a method based on artificial neural networks, we detect the ELG population and measure the equivalent width and flux of the H
α
, H
β
, O
III
, and N
II
emission lines. We explore the ionization mechanism using the diagrams OIII/H
β
versus NII/H
α
(BPT) and EW(H
α
) versus NII/H
α
(WHAN). We identify 1787 ELGs (83%) from the parent sample (2154 galaxies) in the AEGIS field. For the galaxies with reliable EW values that can be placed in the WHAN diagram (2000 galaxies in total), we obtained that 72.8 ± 0.4%, 17.7 ± 0.4%, and 9.4 ± 0.2% are star-forming (SF), active galactic nucleus (Seyfert), and quiescent galaxies, respectively. The distribution of EW(H
α
) is well correlated with the bimodal color distribution of galaxies. Based on the rest-frame (
u
−
r
)–stellar mass diagram, 94% of the blue galaxies are SF galaxies, and 97% of the red galaxies are LINERs or passive galaxies. The nebular extinction and star formation rate (SFR) were computed from the H
α
and H
β
fluxes. We find that the star formation main sequence is described as log SFR
M
⊙
yr
−1
= 0.90
−0.02
+0.02
log
M
⋆
M
⊙
−8.85
−0.20
+0.19
and has an intrinsic scatter of 0.20
−0.01
+0.01
. The cosmic evolution of the SFR density (
ρ
SFR
) is derived at three redshift bins: 0 <
z
≤ 0.15, 0.15 <
z
≤ 0.25, and 0.25 <
z
≤ 0.35, which agrees with previous results that were based on measurements of the H
α
emission line. However, we find an offset with respect to other estimates that were based on the star formation history obtained from fitting the spectral energy distribution of the stellar continuum. We discuss the origin of this discrepancy, which is probably a combination of several factors: the escape of ionizing photons, the SFR tracers, and dust attenuation, among others.
Aims. Our goal is to develop and test a novel methodology to compute accurate close-pair fractions with photometric redshifts. Methods. We improved the currently used methodologies to estimate the ...merger fraction fm from photometric redshifts by (i) using the full probability distribution functions (PDFs) of the sources in redshift space; (ii) including the variation in the luminosity of the sources with z in both the sample selection and the luminosity ratio constrain; and (iii) splitting individual PDFs into red and blue spectral templates to reliably work with colour selections. We tested the performance of our new methodology with the PDFs provided by the ALHAMBRA photometric survey. Results. The merger fractions and rates from the ALHAMBRA survey agree excellently well with those from spectroscopic work for both the general population and red and blue galaxies. With the merger rate of bright (MB ≤ −20−1.1z) galaxies evolving as (1 + z)n, the power-law index n is higher for blue galaxies (n = 2.7 ± 0.5) than for red galaxies (n = 1.3 ± 0.4), confirming previous results. Integrating the merger rate over cosmic time, we find that the average number of mergers per galaxy since z = 1 is Nmred = 0.57 ± 0.05 for red galaxies and Nmblue = 0.26 ± 0.02 for blue galaxies. Conclusions. Our new methodology statistically exploits all the available information provided by photometric redshift codes and yields accurate measurements of the merger fraction by close pairs from using photometric redshifts alone. Current and future photometric surveys will benefit from this new methodology.
The miniJPAS survey quasar selection Martínez-Solaeche, G.; Queiroz, C.; González Delgado, R. M. ...
Astronomy and astrophysics (Berlin),
05/2023, Letnik:
673
Journal Article
Recenzirano
Odprti dostop
This paper is part of large effort within the J-PAS collaboration that aims to classify point-like sources in miniJPAS, which were observed in 60 optical bands over ~1 deg
2
in the AEGIS field. We ...developed two algorithms based on artificial neural networks (ANN) to classify objects into four categories: stars, galaxies, quasars at low redshift (
z
< 2.1), and quasars at high redshift (
z
≥ 2.1). As inputs, we used miniJPAS fluxes for one of the classifiers (ANN
1
) and colours for the other (ANN
2
). The ANNs were trained and tested using mock data in the first place. We studied the effect of augmenting the training set by creating hybrid objects, which combines fluxes from stars, galaxies, and quasars. Nevertheless, the augmentation processing did not improve the score of the ANN. We also evaluated the performance of the classifiers in a small subset of the SDSS DR12Q superset observed by miniJPAS. In the mock test set, the f1-score for quasars at high redshift with the ANN
1
(ANN
2
) are 0.99 (0.99), 0.93 (0.92), and 0.63 (0.57) for 17 <
r
≤ 20, 20 <
r
≤ 22.5, and 22.5 <
r
≤ 23.6, respectively, where r is the J-PAS rSDSS band. In the case of low-redshift quasars, galaxies, and stars, we reached 0.97 (0.97), 0.82 (0.79), and 0.61 (0.58); 0.94 (0.94), 0.90 (0.89), and 0.81 (0.80); and 1.0 (1.0), 0.96 (0.94), and 0.70 (0.52) in the same r bins. In the SDSS DR12Q superset miniJPAS sample, the weighted f1-score reaches 0.87 (0.88) for objects that are mostly within 20 <
r
≤ 22.5. We find that the most common confusion occurs between quasars at low redshift and galaxies in mocks and miniJPAS data. We discuss the origin of this confusion, and we show examples in which these objects present features that are shared by both classes. Finally, we estimate the number of point-like sources that are quasars, galaxies, and stars in miniJPAS.
The miniJPAS survey González Delgado, R. M.; Rodríguez-Martín, J. E.; Díaz-García, L. A. ...
Astronomy and astrophysics (Berlin),
10/2022, Letnik:
666
Journal Article
Recenzirano
Odprti dostop
The miniJPAS survey has observed ∼1 deg
2
of the AEGIS field with 60 bands (spectral resolution of
R
∼ 60) in order to demonstrate the scientific potential of the Javalambre-Physics of the ...Accelerating Universe Astrophysical Survey (J-PAS), which will map ∼8000 deg
2
of the northern sky over the coming years. In particular, this paper demonstrates the potential of J-PAS in detecting groups with mass of up to 10
13
M
⊙
and in characterising their galaxy populations up to
z
∼ 1. The parametric code BaySeAGal is used to derive the stellar population properties by fitting the J-PAS spectral energy distribution (SED) of the galaxy members in 80 groups at
z
≤ 0.8 previously detected by the AMICO code, and of a galaxy field sample retrieved from the whole miniJPAS down to
r
< 22.75 (AB). Blue, red, quiescent, and transition (blue quiescent or green valley) galaxy populations are identified through their rest-frame (extinction-corrected) (
u
−
r
)
int
colour, galaxy stellar mass (
M
⋆
), and specific star formation rate (sSFR). We measure the abundance of these galaxies as a function of
M
⋆
and environment in order to investigate the role that groups play in quenching star formation. Our findings are as follows. (i) The fraction of red and quiescent galaxies in groups increases with
M
⋆
and is always higher in groups (28% on average) than in the field (5%). (ii) The quenched fraction excess (QFE) in groups shows a strong dependence on
M
⋆
, and increases from a few percent for galaxies with
M
⋆
< 10
10
M
⊙
to higher than 60% for galaxies with
M
⋆
> 3 × 10
11
M
⊙
. (iii) The abundance excess of transition galaxies in groups shows a modest dependence on
M
⋆
, being 5%–10% for galaxies with
M
⋆
< 10
11
M
⊙
. (iv) The fading timescale, defined as the time that galaxies in groups spend in the transition phase, is very short (< 1.5 Gyr), indicating that the star formation of galaxies in groups declines very rapidly. (v) The evolution of the galaxy quenching rate in groups shows a modest but significant evolution since
z
∼ 0.8. This latter result is compatible with the expected evolution with constant QFE = 0.4, which has been previously measured for satellites in the nearby Universe, as traced by SDSS. Further, this evolution is consistent with a scenario where the low-mass star forming galaxies in clusters at
z
= 1–1.4 are environmentally quenched, as previously reported by other surveys.
Silica nanoparticles (nanoSiO
) are promising systems that can deliver biologically active compounds to tissues such as the heart in a controllable manner. However, cardiac toxicity induced by ...nanoSiO
has been recently related to abnormal calcium handling and energetic failure in cardiomyocytes. Moreover, the precise mechanisms underlying this energetic debacle remain unclear. In order to elucidate these mechanisms, this article explores the ex vivo heart function and mitochondria after exposure to nanoSiO
.
The cumulative administration of nanoSiO
reduced the mechanical performance index of the rat heart with a half-maximal inhibitory concentration (IC
) of 93 μg/mL, affecting the relaxation rate. In isolated mitochondria nanoSiO
was found to be internalized, inhibiting oxidative phosphorylation and significantly reducing the mitochondrial membrane potential (ΔΨ
). The mitochondrial permeability transition pore (mPTP) was also induced with an increasing dose of nanoSiO
and partially recovered with, a potent blocker of the mPTP, Cyclosporine A (CsA). The activity of aconitase and thiol oxidation, in the adenine nucleotide translocase, were found to be reduced due to nanoSiO
exposure, suggesting that nanoSiO
induces the mPTP via thiol modification and ROS generation. In cardiac cells exposed to nanoSiO
, enhanced viability and reduction of H
O
were observed after application of a specific mitochondrial antioxidant, MitoTEMPO. Concomitantly, CsA treatment in adult rat cardiac cells reduced the nanoSiO
-triggered cell death and recovered ATP production (from 32.4 to 65.4%). Additionally, we performed evaluation of the mitochondrial effect of nanoSiO
in human cardiomyocytes. We observed a 40% inhibition of maximal oxygen consumption rate in mitochondria at 500 μg/mL. Under this condition we identified a remarkable diminution in the spare respiratory capacity. This data indicates that a reduction in the amount of extra ATP that can be produced by mitochondria during a sudden increase in energy demand. In human cardiomyocytes, increased LDH release and necrosis were found at increased doses of nanoSiO
, reaching 85 and 48%, respectively. Such deleterious effects were partially prevented by the application of CsA. Therefore, exposure to nanoSiO
affects cardiac function via mitochondrial dysfunction through the opening of the mPTP.
The aforementioned effects can be partially avoided reducing ROS or retarding the opening of the mPTP. These novel strategies which resulted in cardioprotection could be considered as potential therapies to decrease the side effects of nanoSiO
exposure.
Baryon Acoustic Oscillations (BAOs) provide a 'standard ruler' of known physical length, making it one of the most promising probes of the nature of dark energy (DE). The detection of BAOs as an ...excess of power in the galaxy distribution at a certain scale requires measuring galaxy positions and redshifts. 'Transversal' (or 'angular') BAOs measure the angular size of this scale projected in the sky and provide information about the angular distance. 'Line-of-sight' (or 'radial') BAOs require very precise redshifts, but provide a direct measurement of the Hubble parameter at different redshifts, a more sensitive probe of DE. The main goal of this paper is to show that it is possible to obtain photometric redshifts with enough precision ( sigma z ) to measure BAOs along the line of sight. There is a fundamental limitation as to how much one can improve the BAO measurement by reducing sigma z . We show that sigma z ~ 0.003(1 + z) is sufficient: a much better precision will produce an oversampling of the BAO peak without a significant improvement on its detection, while a much worse precision will result in the effective loss of the radial information. This precision in redshift can be achieved for bright, red galaxies, featuring a prominent 4000 A break, by using a filter system comprising about 40 filters, each with a width close to 100 A, covering the wavelength range from ~4000 to ~8000 A, supplemented by two broad-band filters similar to the Sloan Digital Sky Survey u and z bands. We describe the practical implementation of this idea, a new galaxy survey project, PAU16Physics of the Accelerating Universe (PAU): http://www.ice.cat/pau., to be carried out with a telescope/camera combination with an etendue about 20 m2 deg2, equivalent to a 2 m telescope equipped with a 6 deg2 field of view camera, and covering 8000 deg2 in the sky in four years. We expect to measure positions and redshifts for over 14 million red, early-type galaxies with L > L and iAB 22.5 in the redshift interval 0.1 < z < 0.9, with a precision sigma z < 0.003(1 + z). This population has a number density n 10 -3 Mpc -3 h 3 galaxies within the 9 Gpc3 h -3 volume to be sampled by our survey, ensuring that the error in the determination of the BAO scale is not limited by shot noise. By itself, such a survey will deliver precisions of order 5% in the dark-energy equation of state parameter w, if assumed constant, and can determine its time derivative when combined with future cosmic microwave background measurements. In addition, PAU will yield high-quality redshift and low-resolution spectroscopy for hundreds of millions of other galaxies, including a very significant high-redshift population. The data set produced by this survey will have a unique legacy value, allowing a wide range of astrophysical studies.
Adherence to a Mediterranean diet (MedDiet) is thought to reduce liver steatosis.
To explore the associations with liver steatosis of 3 different diets: a MedDiet + extra-virgin olive oil (EVOO), ...MedDiet + nuts, or a control diet.
This was a subgroup analysis nested within a multicenter, randomized, parallel-group clinical trial, PREvención con DIeta MEDiterránea (PREDIMED trial: ISRCTN35739639), aimed at assessing the effect of a MedDiet on the primary prevention of cardiovascular disease. One hundred men and women (mean age: 64 ± 6 y), at high cardiovascular risk (62% with type 2 diabetes) from the Bellvitge-PREDIMED center were randomly assigned to a MedDiet supplemented with EVOO, a MedDiet supplemented with mixed nuts, or a control diet (advice to reduce all dietary fat). No recommendations to lose weight or increase physical activity were given. Main measurements were the percentage of liver fat and the diagnosis of steatosis, which were determined by NMR imaging. The association of diet with liver fat content was analyzed by bivariate analysis after a median follow-up of 3 y.
Baseline adiposity and cardiometabolic risk factors were similar among the 3 treatment arms. At 3 y after the intervention hepatic steatosis was present in 3 (8.8%), 12 (33.3%), and 10 (33.3%) of the participants in the MedDiet + EVOO, MedDiet + nuts, and control diet groups, respectively (P = 0.027). Respective mean values of liver fat content were 1.2%, 2.7%, and 4.1% (P = 0.07). A tendency toward significance was observed for the MedDiet + EVOO group compared with the control group. Median values of urinary 12(S)-hydroxyeicosatetraenoic acid/creatinine concentrations were significantly (P = 0.001) lower in the MedDiet + EVOO (2.3 ng/mg) than in the MedDiet + nuts (5.0 ng/mg) and control (3.9 ng/mg) groups. No differences in adiposity or glycemic control changes were seen between groups.
An energy-unrestricted MedDiet supplemented with EVOO, a food with potent antioxidant and anti-inflammatory properties, is associated with a reduced prevalence of hepatic steatosis in older individuals at high cardiovascular risk.
Objectives
To define clinical subgroups by cluster analysis in patients with unilateral Meniere disease (MD) and to compare them with the clinical subgroups found in bilateral MD.
Design
A ...cross‐sectional study with a two‐step cluster analysis.
Settings
A tertiary referral multicenter study.
Participants
Nine hundred and eighty‐eight adult patients with unilateral MD. Main outcome measures: best predictors to define clinical subgroups with potential different aetiologies.
Results
We established five clusters in unilateral MD. Group 1 is the most frequently found, includes 53% of patients, and it is defined as the sporadic, classic MD without migraine and without autoimmune disorder (AD). Group 2 is found in 8% of patients, and it is defined by hearing loss, which antedates the vertigo episodes by months or years (delayed MD), without migraine or AD in most of cases. Group 3 involves 13% of patients, and it is considered familial MD, while group 4, which includes 15% of patients, is linked to the presence of migraine in all cases. Group 5 is found in 11% of patients and is defined by a comorbid AD. We found significant differences in the distribution of AD in clusters 3, 4 and 5 between patients with uni‐ and bilateral MD.
Conclusions
Cluster analysis defines clinical subgroups in MD, and it extends the phenotype beyond audiovestibular symptoms. This classification will help to improve the phenotyping in MD and facilitate the selection of patients for randomised clinical trials.
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