2,121 research outputs found
Tests of General Relativity with the Binary Black Hole Signals from the LIGO-Virgo Catalog GWTC-1
Search for the isotropic stochastic background using data from Advanced LIGO’s second observing run
Search for the isotropic stochastic background using data from Advanced LIGO’s second observing run
Effects of transport age (14 d vs. 28 d of age) on blood total cholesterol, insulin and IGF-1 concentrations of veal calves.
The main aim of the current study was to find biomarkers of health in calves transported at different ages. The selected blood parameters were total cholesterol, insulin and IGF-1 and the longitudinal study investigated whether or not these concentrations were different between calves that were transported from the dairy farm to the veal farm at 14 d or 28 d of age. Relationships between these blood variables and health characteristics of veal calves were investigated. In a 34-wk study period, a total of 683 calves originating from 13 Dutch dairy farms were transported at an age of 14 or 28 d to 8 Dutch veal farms. Calves were blood sampled the first wk after birth (mean and SD: 4.4 ± 2.1 d), a day before transport (mean and SD: 25.8 ± 7.3 d) and in wk 2 post-transport (mean and SD: 36.7 ± 12.2 d). In these samples, insulin, IGF-1 and total cholesterol were determined and analyzed with a linear mixed model (LMM). Individual medical treatments were recorded from birth until the day of transport at the dairy farm, and from the moment of arrival at the veal farm until slaughter, and analyzed as a binary response variable (calf treated or not) with a generalized linear mixed model. Fecal (calf with or without loose or liquid manure) and navel (calves with or without swollen and inflamed navel) scores measured during a single visit in wk 2 post-transport were also analyzed as binary response variables, whereas carcass weights at slaughter age were analyzed with a LMM. Cholesterol, insulin and IGF-1 were included as covariates in the previous models to test their relationships with the likelihood of calves being medically treated, fecal and navel scores, and carcass weights. One day before transport 28 d-old calves had higher blood cholesterol (Δ = 0.40 mmol/l) and IGF-1 (Δ = 53.6 ng/ml) concentrations, and evidence of higher insulin (Δ = 12.2 µU/ml) compared with 14 d-old calves. In wk 2 post-transport, 28-d old calves had higher blood IGF-1 (Δ = 21.1 ng/ml), with evidence of higher insulin (Δ = 12.2 µU/ml) concentrations compared with 14-d old calves. Cholesterol concentration measured one day before transport and in wk 2 post-transport had a positive relationship with carcass weight at slaughter (β = 4.8 and 7.7 kg/mmol/l, respectively). Blood cholesterol concentration in wk 2 post-transport was negatively associated with the fecal score measured at the same sampling moment (β = -0.55/mmol/l), with the likelihood of a calf of being treated with antibiotics (β = -0.36/mmol/l) and other medicines (β = -0.45/mmol/l) at the veal farm. Blood IGF-1 concentration in wk 2 post-transport was negatively associated with the likelihood of a calf of being treated with antibiotics and other medicines (both β = -0.01/ng/ml) at the veal farm, and with fecal score recorded in wk 2 post-transport (β = -0.004/ng/ml). When looking at the blood indicators, it appeared that calves transported at 28 d of age were more developed compared with 14 d old calves, thus transport at an older age might be more beneficial for the animals. It can be concluded that both blood cholesterol and IGF-1 concentrations seemed to be valuable biomarkers of health and energy availability in veal calves
Observation of Gravitational Waves from Two Neutron Star-Black Hole Coalescences
We report the observation of gravitational waves from two compact binary coalescences in LIGO's and Virgo's third observing run with properties consistent with neutron star–black hole (NSBH) binaries. The two events are named GW200105_162426 and GW200115_042309, abbreviated as GW200105 and GW200115; the first was observed by LIGO Livingston and Virgo and the second by all three LIGO–Virgo detectors. The source of GW200105 has component masses 8.9+1.2-1.5 and 1.9+0.3-0.2 M⊙, whereas the source of GW200115 has component masses 5.7+1.8-2.1 and 1.5+0.7-0.3 M⊙(all measurements quoted at the 90% credible level). The probability that the secondary's mass is below the maximal mass of a neutron star is 89%–96% and 87%–98%, respectively, for GW200105 and GW200115, with the ranges arising from different astrophysical assumptions. The source luminosity distances are and 280+110-110 and 300+150-100 Mpc, respectively. The magnitude of the primary spin of GW200105 is less than 0.23 at the 90% credible level, and its orientation is unconstrained. For GW200115, the primary spin has a negative spin projection onto the orbital angular momentum at 88% probability. We are unable to constrain the spin or tidal deformation of the secondary component for either event. We infer an NSBH merger rate density of 45+75-33 Gpc-3 yr-1 when assuming that GW200105 and GW200115 are representative of the NSBH population or 130+112-69 Gpc-3 yr-1 under the assumption of a broader distribution of component masses
Population Properties of Compact Objects from the Second LIGO-Virgo Gravitational-Wave Transient Catalog
Virgo detector characterization and data quality: tools
Detector characterization and data quality studies—collectively referred to as DetChar activities in this article—are paramount to the scientific exploitation of the joint dataset collected by the LIGO-Virgo-KAGRA global network of ground-based gravitational-wave (GW) detectors. They take place during each phase of the operation of the instruments (upgrade, tuning and optimization, data taking), are required at all steps of the dataflow (from data acquisition to the final list of GW events) and operate at various latencies (from near real-time to vet the public alerts to offline analyses). This work requires a wide set of tools which have been developed over the years to fulfill the requirements of the various DetChar studies: data access and bookkeeping; global monitoring of the instruments and of the different steps of the data processing; studies of the global properties of the noise at the detector outputs; identification and follow-up of noise peculiar features (whether they be transient or continuously present in the data); quick processing of the public alerts. The present article reviews all the tools used by the Virgo DetChar group during the third LIGO-Virgo Observation Run (O3, from April 2019 to March 2020), mainly to analyze the Virgo data acquired at EGO. Concurrently, a companion article focuses on the results achieved by the DetChar group during the O3 run using these tools
GWTC-1: A Gravitational-Wave Transient Catalog of Compact Binary Mergers Observed by LIGO and Virgo during the First and Second Observing Runs
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