118 research outputs found
More pace variation and pack formation in successful world-class 10,000-m runners than in less successful competitors
Purpose To determine different relationships between, and predictive ability of, performance variables at intermediate distances with finishing time in elite male 10,000 m runners. Methods Official electronic finishing and 100 m split times of the menâs 10,000 m finals at the 2008 and 2016 Olympic Games and IAAF World Championships in 2013 and 2017 were obtained (125 athlete performances in total). Correlations were calculated between finishing times and positions and performance variables relating to speed, position, time to the leader and time to the runner in front at 2000, 4000, 6000, 8000 and 9900 m. Stepwise linear regression analysis was conducted between finishing times and positions and these variables across the race. One-way ANOVA was performed to identify differences between intermediate distances. Results The standard deviation and kurtosis of mean time, skewness of mean time and position and time difference to the leader were either correlated with or significantly contributed to predictions of finishing time and position at one of the analysed distance at least (0.81 â„ r â„ 0.30 and 0.0001 †P †0.03, respectively). These variables also displayed variation across the race (0.0001 †P †0.05). Conclusions The ability to undertake a high degree of pace variability, mostly characterised by acceleration in the final stages, is strongly associated with the achievement of high finishing positions in championship 10000 m racing. Furthermore, the adoption and maintenance of positions close to the front of the race from the early stages is important to achieve a high finishing position
The Low Redshift survey at Calar Alto (LoRCA)
The Baryon Acoustic Oscillation (BAO) feature in the power spectrum of
galaxies provides a standard ruler to measure the accelerated expansion of the
Universe. To extract all available information about dark energy, it is
necessary to measure a standard ruler in the local, z<0.2, universe where dark
energy dominates most the energy density of the Universe. Though the volume
available in the local universe is limited, it is just big enough to measure
accurately the long 100 Mpc/h wave-mode of the BAO. Using cosmological N-body
simulations and approximate methods based on Lagrangian perturbation theory, we
construct a suite of a thousand light-cones to evaluate the precision at which
one can measure the BAO standard ruler in the local universe. We find that
using the most massive galaxies on the full sky (34,000 sq. deg.), i.e. a
K(2MASS)<14 magnitude-limited sample, one can measure the BAO scale up to a
precision of 4\% and 1.2\% using reconstruction). We also find that such a
survey would help to detect the dynamics of dark energy.Therefore, we propose a
3-year long observational project, named the Low Redshift survey at Calar Alto
(LoRCA), to observe spectroscopically about 200,000 galaxies in the northern
sky to contribute to the construction of aforementioned galaxy sample. The
suite of light-cones is made available to the public.Comment: 15 pages. Accepted in MNRAS. Please visit our website:
http://lorca-survey.ft.uam.es
Biological control of soil-borne phytopathogenic fungi through onion waste composting: implications for circular economy perspective
The production of onion waste derived mainly from bulbs affected by fungal diseases, during onion classification and storage presents an important agro-environmental issue in onion production regions. Composting is an environmentally friendly strategy to recycle agricultural waste and produce organic fertilizers. Modifications of the microbial community in soil can affect the ability of pathogen propagules to survive, germinate and infect plant roots. Hence, the main objective of this work was to exploring the mechanisms involved on the presence of three soil-borne phytopathogenic fungi during the composting process of onion waste under the hypothesis if that the resulting compost effectively prevents or minimizes the dispersion of phytopathogenic fungi. To this end, three composting piles of 60 tonnes each were built by layering onion waste affected by phytopathogenic fungi and cow dung at 1:1 ratio. Temperature, moisture, pH, electrical conductivity (EC) and Aspergillus niger, Penicillium sp. and Fusarium sp. growth were monitored for 100 days. During the first 28 days of composting, the presence of phytopathogenic fungi increased significantly showing thereafter a downward trend. Final estimations of fungal populations densities indicated a predominance of A. niger and an effective reduction in the abundance of Fusarium sp. This pilot-scale work demonstrates the feasibility of composting onion waste contaminated with phytopathogenic fungi and highlights the positive environmental impact associated with this practice. Therefore, the composting of onion waste and cow dung is a feasible and sustainable procedure to recycle onion waste and to promote circular economy in onion production regions.Fil: Chorolque, A.. Universidad Nacional del Comahue; ArgentinaFil: Pellejero, G.. Universidad Nacional del Comahue; ArgentinaFil: Sosa, MarĂa Cristina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Patagonia Confluencia. Centro de Investigaciones en ToxicologĂa Ambiental y AgrobiotecnologĂa del Comahue. Instituto de BiotecnologĂa Agropecuaria del Comahue | Universidad Nacional del Comahue. Facultad de Ciencias Agrarias. Centro de Investigaciones en ToxicologĂa Ambiental y AgrobiotecnologĂa del Comahue. Instituto de BiotecnologĂa Agropecuaria del Comahue; ArgentinaFil: Palacios, J.. Universidad Nacional del Comahue; ArgentinaFil: Aschkar, Gabriela Marisa. Universidad Nacional del Comahue; ArgentinaFil: GarcĂa Delgado, C.. Universidad AutĂłnoma de Madrid; EspañaFil: JimĂ©nez Ballesta, R. Universidad AutĂłnoma de Madrid; Españ
The Low Redshift survey at Calar Alto (LoRCA)
The Baryon Acoustic Oscillation (BAO) feature in the power spectrum of
galaxies provides a standard ruler to measure the accelerated expansion of the
Universe. To extract all available information about dark energy, it is
necessary to measure a standard ruler in the local, z<0.2, universe where dark
energy dominates most the energy density of the Universe. Though the volume
available in the local universe is limited, it is just big enough to measure
accurately the long 100 Mpc/h wave-mode of the BAO. Using cosmological N-body
simulations and approximate methods based on Lagrangian perturbation theory, we
construct a suite of a thousand light-cones to evaluate the precision at which
one can measure the BAO standard ruler in the local universe. We find that
using the most massive galaxies on the full sky (34,000 sq. deg.), i.e. a
K(2MASS)<14 magnitude-limited sample, one can measure the BAO scale up to a
precision of 4\% and 1.2\% using reconstruction). We also find that such a
survey would help to detect the dynamics of dark energy.Therefore, we propose a
3-year long observational project, named the Low Redshift survey at Calar Alto
(LoRCA), to observe spectroscopically about 200,000 galaxies in the northern
sky to contribute to the construction of aforementioned galaxy sample. The
suite of light-cones is made available to the public.Comment: 15 pages. Accepted in MNRAS. Please visit our website:
http://lorca-survey.ft.uam.es
The Fourteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the extended Baryon Oscillation Spectroscopic Survey and from the second phase of the Apache Point Observatory Galactic Evolution Experiment
The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in
operation since July 2014. This paper describes the second data release from
this phase, and the fourteenth from SDSS overall (making this, Data Release
Fourteen or DR14). This release makes public data taken by SDSS-IV in its first
two years of operation (July 2014-2016). Like all previous SDSS releases, DR14
is cumulative, including the most recent reductions and calibrations of all
data taken by SDSS since the first phase began operations in 2000. New in DR14
is the first public release of data from the extended Baryon Oscillation
Spectroscopic Survey (eBOSS); the first data from the second phase of the
Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2),
including stellar parameter estimates from an innovative data driven machine
learning algorithm known as "The Cannon"; and almost twice as many data cubes
from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous
release (N = 2812 in total). This paper describes the location and format of
the publicly available data from SDSS-IV surveys. We provide references to the
important technical papers describing how these data have been taken (both
targeting and observation details) and processed for scientific use. The SDSS
website (www.sdss.org) has been updated for this release, and provides links to
data downloads, as well as tutorials and examples of data use. SDSS-IV is
planning to continue to collect astronomical data until 2020, and will be
followed by SDSS-V.Comment: SDSS-IV collaboration alphabetical author data release paper. DR14
happened on 31st July 2017. 19 pages, 5 figures. Accepted by ApJS on 28th Nov
2017 (this is the "post-print" and "post-proofs" version; minor corrections
only from v1, and most of errors found in proofs corrected
Comparing approximate methods for mock catalogues and covariance matrices - I. Correlation function
Computational astrophysic
Comparing approximate methods for mock catalogues and covariance matrices \u2013 III: bispectrum
We compare the measurements of the bispectrum and the estimate of its covariance obtained from a set of different methods for the efficient generation of approximate dark matter halo catalogues to the same quantities obtained from full N-body simulations. To this purpose we employ a large set of 300 realizations of the same cosmology for each method, run with matching initial conditions in order to reduce the contribution of cosmic variance to the comparison. In addition, we compare how the error on cosmological parameters such as linear and non-linear bias parameters depends on the approximate method used for the determination of the bispectrum variance. As general result, most methods provide errors within 10 per cent of the errors estimated from N-body simulations. Exceptions are those methods requiring calibration of the clustering amplitude but restrict this to 2-point statistics. Finally we test how our results are affected by being limited to a few hundreds measurements from N-body simulation by comparing with a larger set of several thousands of realizations performed with one approximate method
Cosmological implications of baryon acoustic oscillation measurements
We derive constraints on cosmological parameters and tests of dark energy models from the combination of baryon acoustic oscillation (BAO) measurements with cosmic microwave background (CMB) data and a recent reanalysis of Type Ia supernova (SN) data. In particular, we take advantage of high-precision BAO measurements from galaxy clustering and the Lyman-α forest (LyaF) in the SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS). Treating the BAO scale as an uncalibrated standard ruler, BAO data alone yield a high confidence detection of dark energy; in combination with the CMB angular acoustic scale they further imply a nearly flat universe. Adding the CMB-calibrated physical scale of the sound horizon, the combination of BAO and SN data into an âinverse distance ladderâ yields a measurement of
H0 =67.3 ± 1.1 km s-1 Mpc-1, with 1.7% precision. This measurement assumes standard prerecombination physics but is insensitive to assumptions about dark energy or space curvature, so agreement with CMB-based estimates that assume a flat Î CDM cosmology is an important corroboration of this minimal cosmological model. For constant dark energy (Î), our BAO + SN + CMB
combination yields matter density Ωm = 0.301 ± 0.008 and curvature Ωk = -0.003 ± 0.003. When we allow more general forms of evolving dark energy, the BAO + SN + CMB parameter constraints are always consistent with flat Î CDM values at â1Ï. While the overall Ï2 of model fits is satisfactory, the LyaF BAO measurements are in moderate (2â2.5Ï) tension with model predictions. Models with early dark energy that tracks the dominant energy component at high redshift remain consistent with our expansion history constraints, and they yield a higher H0 and lower matter clustering amplitude, improving agreement with some low redshift observations. Expansion history alone yields an upper limit on the summed mass of neutrino species, âmÎœ (95% confidence), improving to âmÎœ if we include the lensing signal in the Planck CMB power spectrum. In a flat Î CDM model that allows extra relativistic species, our data combination yields Neff = 3.43 ± 0.26; while the LyaF BAO data prefer higher Neff when excluding galaxy BAO, the galaxy BAO alone favor Neff â 3. When structure growth is extrapolated forward from the CMB to low redshift, standard dark energy models constrained by our data predict a level of matter clustering that is high compared to most, but not all, observational estimates
The clustering of the SDSS-IV extended Baryon Oscillation Spectroscopic Survey DR14 quasar sample: first measurement of baryon acoustic oscillations between redshift 0.8 and 2.2
We present measurements of the Baryon Acoustic Oscillation (BAO) scale in
redshift-space using the clustering of quasars. We consider a sample of 147,000
quasars from the extended Baryon Oscillation Spectroscopic Survey (eBOSS)
distributed over 2044 square degrees with redshifts and measure
their spherically-averaged clustering in both configuration and Fourier space.
Our observational dataset and the 1400 simulated realizations of the dataset
allow us to detect a preference for BAO that is greater than 2.8. We
determine the spherically averaged BAO distance to to 3.8 per cent
precision: Mpc.
This is the first time the location of the BAO feature has been measured
between redshifts 1 and 2. Our result is fully consistent with the prediction
obtained by extrapolating the Planck flat CDM best-fit cosmology. All
of our results are consistent with basic large-scale structure (LSS) theory,
confirming quasars to be a reliable tracer of LSS, and provide a starting point
for numerous cosmological tests to be performed with eBOSS quasar samples. We
combine our result with previous, independent, BAO distance measurements to
construct an updated BAO distance-ladder. Using these BAO data alone and
marginalizing over the length of the standard ruler, we find at 6.6 significance when testing a CDM model with free
curvature.Comment: Accepted by MNRAS; BAO distance likelihood available in source files
'QSOv1.9fEZmock_BAOchi2.dat'; full set of data to be public eventually from
SDSS websit
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