124 research outputs found
The Lyman- forest catalog from the Dark Energy Spectroscopic Instrument Early Data Release
We present and validate the catalog of Lyman- forest fluctuations for
3D analyses using the Early Data Release (EDR) from the Dark Energy
Spectroscopic Instrument (DESI) survey. We used 96,317 quasars collected from
DESI Survey Validation (SV) data and the first two months of the main survey
(M2). We present several improvements to the method used to extract the
Lyman- absorption fluctuations performed in previous analyses from the
Sloan Digital Sky Survey (SDSS). In particular, we modify the weighting scheme
and show that it can improve the precision of the correlation function
measurement by more than 20%. This catalog can be downloaded from
https://data.desi.lbl.gov/public/edr/vac/edr/lya/fuji/v0.3 and it will be used
in the near future for the first DESI measurements of the 3D correlations in
the Lyman- forest
Optimal 1D Ly Forest Power Spectrum Estimation -- III. DESI early data
The one-dimensional power spectrum of the Ly forest
provides important information about cosmological and astrophysical parameters,
including constraints on warm dark matter models, the sum of the masses of the
three neutrino species, and the thermal state of the intergalactic medium. We
present the first measurement of with the quadratic maximum
likelihood estimator (QMLE) from the Dark Energy Spectroscopic Instrument
(DESI) survey early data sample. This early sample of quasars is
already comparable in size to the largest previous studies, and we conduct a
thorough investigation of numerous instrumental and analysis systematic errors
to evaluate their impact on DESI data with QMLE. We demonstrate the excellent
performance of the spectroscopic pipeline noise estimation and the impressive
accuracy of the spectrograph resolution matrix with two-dimensional image
simulations of raw DESI images that we processed with the DESI spectroscopic
pipeline. We also study metal line contamination and noise calibration
systematics with quasar spectra on the red side of the Ly emission
line. In a companion paper, we present a similar analysis based on the Fast
Fourier Transform estimate of the power spectrum. We conclude with a comparison
of these two approaches and implications for the upcoming DESI Year 1 analysis.Comment: 23 pages, 20 figures. To be published in MNRA
The Dark Energy Spectroscopic Instrument: one-dimensional power spectrum from first Ly α forest samples with Fast Fourier Transform
We present the one-dimensional Ly α forest power spectrum measurement using the first data provided by the Dark Energy Spectroscopic Instrument (DESI). The data sample comprises 26 330 quasar spectra, at redshift z > 2.1, contained in the DESI Early Data Release and the first 2 months of the main survey. We employ a Fast Fourier Transform (FFT) estimator and compare the resulting power spectrum to an alternative likelihood-based method in a companion paper. We investigate methodological and instrumental contaminants associated with the new DESI instrument, applying techniques similar to previous Sloan Digital Sky Survey (SDSS) measurements. We use synthetic data based on lognormal approximation to validate and correct our measurement. We compare our resulting power spectrum with previous SDSS and high-resolution measurements. With relatively small number statistics, we successfully perform the FFT measurement, which is already competitive in terms of the scale range. At the end of the DESI survey, we expect a five times larger Ly α forest sample than SDSS, providing an unprecedented precise one-dimensional power spectrum measurement
Optimal 1D Ly α forest power spectrum estimation – III. DESI early data
The 1D power spectrum P1D of the Ly α forest provides important information about cosmological and astrophysical parameters, including constraints on warm dark matter models, the sum of the masses of the three neutrino species, and the thermal state of the intergalactic medium. We present the first measurement of P1D with the quadratic maximum likelihood estimator (QMLE) from the Dark Energy Spectroscopic Instrument (DESI) survey early data sample. This early sample of 54 600 quasars is already comparable in size to the largest previous studies, and we conduct a thorough investigation of numerous instrumental and analysis systematic errors to evaluate their impact on DESI data with QMLE. We demonstrate the excellent performance of the spectroscopic pipeline noise estimation and the impressive accuracy of the spectrograph resolution matrix with 2D image simulations of raw DESI images that we processed with the DESI spectroscopic pipeline. We also study metal line contamination and noise calibration systematics with quasar spectra on the red side of the Ly α emission line. In a companion paper, we present a similar analysis based on the Fast Fourier Transform estimate of the power spectrum. We conclude with a comparison of these two approaches and discuss the key sources of systematic error that we need to address with the upcoming DESI Year 1 analysis
In vitro antiproliferative/cytotoxic activity on cancer cell lines of a cardanol and a cardol enriched from Thai Apis mellifera propolis
<p>Abstract</p> <p>Background</p> <p>Propolis is a complex resinous honeybee product. It is reported to display diverse bioactivities, such as antimicrobial, anti-inflammatory and anti-tumor properties, which are mainly due to phenolic compounds, and especially flavonoids. The diversity of bioactive compounds depends on the geography and climate, since these factors affect the floral diversity. Here, <it>Apis mellifera </it>propolis from Nan province, Thailand, was evaluated for potential anti-cancer activity.</p> <p>Methods</p> <p>Propolis was sequentially extracted with methanol, dichloromethane and hexane and the cytotoxic activity of each crude extract was assayed for antiproliferative/cytotoxic activity <it>in vitro </it>against five human cell lines derived from duet carcinoma (BT474), undifferentiated lung (Chaco), liver hepatoblastoma (Hep-G<sub>2</sub>), gastric carcinoma (KATO-III) and colon adenocarcinoma (SW620) cancers. The human foreskin fibroblast cell line (Hs27) was used as a non-transformed control. Those crude extracts that displayed antiproliferative/cytotoxic activity were then further fractionated by column chromatography using TLC-pattern and MTT-cytotoxicity bioassay guided selection of the fractions. The chemical structure of each enriched bioactive compound was analyzed by nuclear magnetic resonance and mass spectroscopy.</p> <p>Results</p> <p>The crude hexane and dichloromethane extracts of propolis displayed antiproliferative/cytotoxic activities with IC<sub>50 </sub>values across the five cancer cell lines ranging from 41.3 to 52.4 μg/ml and from 43.8 to 53.5 μg/ml, respectively. Two main bioactive components were isolated, one cardanol and one cardol, with broadly similar <it>in vitro </it>antiproliferation/cytotoxicity IC<sub>50 </sub>values across the five cancer cell lines and the control Hs27 cell line, ranging from 10.8 to 29.3 μg/ml for the cardanol and < 3.13 to 5.97 μg/ml (6.82 - 13.0 μM) for the cardol. Moreover, both compounds induced cytotoxicity and cell death without DNA fragmentation in the cancer cells, but only an antiproliferation response in the control Hs27 cells However, these two compounds did not account for the net antiproliferation/cytotoxic activity of the crude extracts suggesting the existence of other potent compounds or synergistic interactions in the propolis extracts<sub>.</sub></p> <p>Conclusion</p> <p>This is the first report that Thai <it>A. mellifera </it>propolis contains at least two potentially new compounds (a cardanol and a cardol) with potential anti-cancer bioactivity. Both could be alternative antiproliferative agents for future development as anti-cancer drugs.</p
Validation of the Scientific Program for the Dark Energy Spectroscopic Instrument
The Dark Energy Spectroscopic Instrument (DESI) was designed to conduct a
survey covering 14,000 deg over five years to constrain the cosmic
expansion history through precise measurements of Baryon Acoustic Oscillations
(BAO). The scientific program for DESI was evaluated during a five month Survey
Validation (SV) campaign before beginning full operations. This program
produced deep spectra of tens of thousands of objects from each of the stellar
(MWS), bright galaxy (BGS), luminous red galaxy (LRG), emission line galaxy
(ELG), and quasar target classes. These SV spectra were used to optimize
redshift distributions, characterize exposure times, determine calibration
procedures, and assess observational overheads for the five-year program. In
this paper, we present the final target selection algorithms, redshift
distributions, and projected cosmology constraints resulting from those
studies. We also present a `One-Percent survey' conducted at the conclusion of
Survey Validation covering 140 deg using the final target selection
algorithms with exposures of a depth typical of the main survey. The Survey
Validation indicates that DESI will be able to complete the full 14,000 deg
program with spectroscopically-confirmed targets from the MWS, BGS, LRG, ELG,
and quasar programs with total sample sizes of 7.2, 13.8, 7.46, 15.7, and 2.87
million, respectively. These samples will allow exploration of the Milky Way
halo, clustering on all scales, and BAO measurements with a statistical
precision of 0.28% over the redshift interval , 0.39% over the redshift
interval , and 0.46% over the redshift interval .Comment: 42 pages, 18 figures, accepted by A
The Early Data Release of the Dark Energy Spectroscopic Instrument
\ua9 2024. The Author(s). Published by the American Astronomical Society. The Dark Energy Spectroscopic Instrument (DESI) completed its 5 month Survey Validation in 2021 May. Spectra of stellar and extragalactic targets from Survey Validation constitute the first major data sample from the DESI survey. This paper describes the public release of those spectra, the catalogs of derived properties, and the intermediate data products. In total, the public release includes good-quality spectral information from 466,447 objects targeted as part of the Milky Way Survey, 428,758 as part of the Bright Galaxy Survey, 227,318 as part of the Luminous Red Galaxy sample, 437,664 as part of the Emission Line Galaxy sample, and 76,079 as part of the Quasar sample. In addition, the release includes spectral information from 137,148 objects that expand the scope beyond the primary samples as part of a series of secondary programs. Here, we describe the spectral data, data quality, data products, Large-Scale Structure science catalogs, access to the data, and references that provide relevant background to using these spectra
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