349 research outputs found
Detection, Localization and Characterization of Gravitational Wave Bursts in a Pulsar Timing Array
Efforts to detect gravitational waves by timing an array of pulsars have
focused traditionally on stationary gravitational waves: e.g., stochastic or
periodic signals. Gravitational wave bursts --- signals whose duration is much
shorter than the observation period --- will also arise in the pulsar timing
array waveband. Sources that give rise to detectable bursts include the
formation or coalescence of supermassive black holes (SMBHs), the periapsis
passage of compact objects in highly elliptic or unbound orbits about a SMBH,
or cusps on cosmic strings. Here we describe how pulsar timing array data may
be analyzed to detect and characterize these bursts. Our analysis addresses, in
a mutually consistent manner, a hierarchy of three questions: \emph{i}) What
are the odds that a dataset includes the signal from a gravitational wave
burst? \emph{ii}) Assuming the presence of a burst, what is the direction to
its source? and \emph{iii}) Assuming the burst propagation direction, what is
the burst waveform's time dependence in each of its polarization states?
Applying our analysis to synthetic data sets we find that we can \emph{detect}
gravitational waves even when the radiation is too weak to either localize the
source of infer the waveform, and \emph{detect} and \emph{localize} sources
even when the radiation amplitude is too weak to permit the waveform to be
determined. While the context of our discussion is gravitational wave detection
via pulsar timing arrays, the analysis itself is directly applicable to
gravitational wave detection using either ground or space-based detector data.Comment: 43 pages, 13 figures, submitted to ApJ
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THERMAL AND SPECTROSCOPIC ANALYSES OF CAUSTIC LIDE SOLVENT EXTRACTION SOLVENT CONTACTED WITH 16 MOLAR AND 8 MOLAR NITRIC ACID
Thermal and spectroscopic analyses were performed on multiple layers formed from contacting Caustic Side Solvent Extraction (CSSX) solvent with 1 M or 3 M nitric acid. A slow chemical reaction occurs (i.e., over several weeks) between the solvent and 1 M or 3 M nitric acid as evidenced by color changes and the detection of nitro groups in the infrared spectrum of the aged samples. Thermal analysis revealed that decomposition of the resulting mixture does not meet the definition of explosive or deflagrating material
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THERMAL AND SPECTROSCOPIC ANALYSES OF CAUSTIC SIDE SOLVENT EXTRACTION SOLVENT CONTACTED WITH 1 MOLARAND 3 MOLAR NITRIC ACID
Thermal and spectroscopic analyses were performed on multiple layers formed from contacting Caustic Side Solvent Extraction (CSSX) solvent with 1 M or 3 M nitric acid. A slow chemical reaction occurs (i.e., over several weeks) between the solvent and 1 M or 3 M nitric acid as evidenced by color changes and the detection of nitro groups in the infrared spectrum of the aged samples. Thermal analysis revealed that decomposition of the resulting mixture does not meet the definition of explosive or deflagrating material
The Water Incident Database (WAID) 2012 to 2019: a systematic evaluation of the documenting of UK drownings
Background. Death by drowning is a leading cause of accidental death in the United Kingdom (UK) and worldwide. The World Health Organization (WHO) states that effective documentation of drowning is required to describe drowning frequency and to underpin effective drowning prevention intervention, thus improving the quality of data describing drowning frequency represents a key initiative. The water incident database (WAID) has been used to document UK fatal and non-fatal water-based incidents since 2009. WAID has not undergone a systematic evaluation of its data or data collection procedures to establish if the database meets the WHO requirements. The present study investigated the characteristics of UK fatal drowning incidents and audited current WAID data capture procedures. Methods. Data for the fatal drowning cases recorded between 2012 and 2019 were reviewed. Descriptive data were generated 1) to describe fatal drownings in the UK's WAID in this period; 2) a sub-set of drownings were audited i) for completeness of data entry and, based on source documents, ii) for quality of data entry; 3) these processes were used to make recommendations for onward revisions to WAID. Results. A total of 5,501 fatalities were recorded between 2012-2019. Drowning was most frequent amongst males aged 35 to 60 years (n=1,346), whilst suspected accidents and suicides accounted for 44% and 35% of fatalities. Suicide by drowning was at a peak in the most recent year of data analysed (i.e., 2019; 279 cases) highlighting an urgent need for targeted intervention. Audit part 2i) indicated that 16% of all fields were incomplete, thus indicating potential redundancy, duplication, or the need for onward review. Audit part 2ii) indicated high levels of agreement (80±12%) between audited cases and the âtrueâ WAID entries. Conclusions. This study confirms WAID as a rigorous, transparent and effective means of documenting UK drownings thereby meeting WHO requirements for data quality; yet future improvements are recommended. Such findings allow researchers and policy makers to use WAID to further investigate UK drowning with a view to improving public safety measures and drowning prevention interventions. Observations alongside several expert recommendations have informed a revised version of WAID
Mapping and manipulating the Mycobacterium tuberculosis transcriptome using a transcription factor overexpression-derived regulatory network
Effects of an active warm-up on variation in bench press and back squat (upper and lower body measures).
The present study investigated the magnitude of diurnal variation in back squat and bench press using the MuscleLab linear encoder over three different loads and assessed the benefit of an active warm-up to establish whether diurnal variation could be negated. Ten resistance-trained males underwent (mean ± SD: age 21.0 ± 1.3â
years, height 1.77 ± 0.06â
m, and body mass 82.8 ± 14.9â
kg) three sessions. These included control morning (M, 07:30â
h) and evening (E, 17:30â
h) sessions (5-min standardized warm-up at 150â
W, on a cycle ergometer), and one further session consisting of an extended active warm-up morning trial (ME, 07:30â
h) until rectal temperature (Trec) reached previously recorded resting evening levels (at 150â
W, on a cycle ergometer). All sessions included handgrip, followed by a defined program of bench press (at 20, 40, and 60â
kg) and back squat (at 30, 50, and 70â
kg) exercises. A linear encoder was attached to an Olympic bar used for the exercises and average force (AF), peak velocity (PV), and time to peak velocity (tPV) were measured (MuscleLab software; MuscleLab Technology, Langesund, Norway) during the concentric phase of the movements. Values for Trec were higher in the E session compared to values in the M session (Î0.53â
°C, P  0.05) to increase from M to E levels. Therefore, MuscleLab linear encoder could detect meaningful differences between the morning and evening for all variables. However, the diurnal variation in bench press and back squat (measures of lower and upper body force and power output) is not explained by time-of-day oscillations in Trec
Modifying the pre-pitch entry practices of professional soccer substitutes may contribute towards improved movement-related performance indicators on match-day: A case study.
Modifying a soccer substituteâs pre-pitch-entry activities may represent an opportunity to maximise physical performance and minimise injury-risk following match-introduction. Using a professional team that has previously participated in substitute profiling research, this follow-up case study investigated the effects of a modified match-day protocol that included substitutes; 1) performing a new pre-match warm-up alongside members of the starting team (as opposed to a separate substitute-only warm-up), 2) participating in a staff-led half-time rewarm-up (as opposed to player-led half-time activities), and 3) receiving ongoing education focusing on the efficacy of (re)warm-up activities. English Championship substitutes (n = 15) were monitored using Micro-electromechanical Systems during 13 matches incorporating the modified practices (35 observations). On an individual player basis, data were organised into bouts of warm-up activity (pre-pitch-entry) and five min epochs of match-play (post-pitch-entry). Linear mixed modelling assessed the influence of âboutâ and âepochâ, position, and scoreline. Substitutes performed 3±1 rewarm-up boutsâplayer-1âmatch-1 between kick-off and pitch-entry, which were shorter (-17.2 to -27.1 min) and elicited less distance (-696 to -1257 m) than the pre-match warm-up (pâ€0.001). Compared with previous data, heightened absolute movement responses were observed during the pre-match and staff-led half-time (re)warm-ups, alongside greater relative distances covered during player-led activities performed between kick-off and pitch-entry. Whilst less distance (-10%) was covered during the second versus first five min period following match-introduction, values remained higher than previously reported. Between pitch-entry and the end of the match, the scoreline improved and worsened following 26% and 11% of substitutions, respectively; a favourable record compared with existing observations. Acknowledging the likely contribution from external factors, this case study reports heightened movement profiles and improved match scorelines when pre-pitch-entry practices were modified. Practitioners should note the potential influence of match-day activities on the physical responses of soccer substitutes and, if deemed necessary, consider adapting their pre-pitch-entry routines accordingly
The physical demands of professional soccer goalkeepers throughout a week-long competitive microcycle and transiently throughout match-play.
The physical demands of English Premier League soccer goalkeepers were quantified during training and match-play in a two-part study. Goalkeeper-specific micromechanical electrical systems (MEMS) devices, profiled training and match-day activities throughout one competitive week (n=8; part A). Changes in MEMS-derived outputs were also profiled throughout match-play (100 matches; n=8, 18±14 observations per goalkeeper; part B). In part A, goalkeeping-training elicited the most dives (51±11) versus all activities (all pâ€0.030) except shooting-training (p=0.069). Small-sided games elicited the fewest (5±3) dives (all pâ€0.012). High-speed distance covered in match (103±72 m) was similar to goalkeeping-training (p=0.484), while exceeding shooting-training, small-sided games, pre-match shooting, and pre-match warm-up (all p=0.012). Most changes of direction (34±12) and explosive efforts (70±18) occurred during goalkeeping-training, with values exceeding match (both p=0.012). In part B, between-half reductions in total distance, but increased high-speed changes of direction and explosive efforts, occurred (both pâ€0.05). Excluding the number of high jumps, all variables differed from 0-15-min during at least one match epoch, with more dives (1.3±1.4 vs 1.0±1.1) and explosive efforts (2.5±2.4 vs 2.0±1.8) performed between 75-90-min versus 0-15-min (all p<0.05). These data highlight the differing physical demands of various activities performed by professional soccer goalkeepers throughout a competitive week
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TAILORING INORGANIC SORBENTS FOR SRS STRONTIUM AND ACTINIDE SEPARATIONS: OPTIMIZED MONOSODIUM TITANATE PHASE II FINAL REPORT
This document provides a final report of Phase II testing activities for the development of a modified monosodium titanate (MST) that exhibits improved strontium and actinide removal characteristics compared to the baseline MST material. The activities included determining the key synthesis conditions for preparation of the modified MST, preparation of the modified MST at a larger scale by a commercial vendor, demonstration of the strontium and actinide removal characteristics with actual tank waste supernate and measurement of filtration characteristics. Key findings and conclusions include the following. Testing evaluated three synthetic methods and eleven process parameters for the optimum synthesis conditions for the preparation on an improved form of MST. We selected the post synthesis method (Method 3) for continued development based on overall sorbate removal performance. We successfully prepared three batches of the modified MST using Method 3 procedure at a 25-gram scale. The laboratory prepared modified MST exhibited increased sorption kinetics with simulated and actual waste solutions and similar filtration characteristics to the baseline MST. Characterization of the modified MST indicated that the post synthesis treatment did not significantly alter the particle size distribution, but did significantly increase the surface area and porosity compared to the original MST. Testing indicated that the modified MST exhibits reduced affinity for uranium compared to the baseline MST, reducing risk of fissile loading. Shelf-life testing indicated no change in strontium and actinide performance removal after storing the modified MST for 12-months at ambient laboratory temperature. The material releases oxygen during the synthesis and continues to offgas after the synthesis at a rapidly diminishing rate until below a measurable rate after 4 months. Optima Chemical Group LLC prepared a 15-kilogram batch of the modified MST using the post synthesis procedure (Method 3). Performance testing with simulated and actual waste solutions indicated that the material performs as well as or better than batches of modified MST prepared at the laboratory-scale. Particle size data of the vendor-prepared modified MST indicates a broader distribution centered at a larger particle size and microscopy shows more irregular particle morphology compared to the baseline MST and laboratory prepared modified MST. Stirred-cell (i.e., dead-end) filter testing revealed similar filtration rates relative to the baseline MST for both the laboratory and vendor-prepared modified MST materials. Crossflow filtration testing indicated that with MST-only slurries, the baseline MST produced between 30-100% higher flux than the vendor-prepared modified MST at lower solids loadings and comparable flux at higher solids loadings. With sludge-MST slurries, the modified MST produced 1.5-2.2 times higher flux than the baseline MST at all solids loadings. Based on these findings we conclude that the modified MST represents a much improved sorbent for the separation of strontium and actinides from alkaline waste solutions and recommend continued development of the material as a replacement for the baseline MST for waste treatment facilities at the Savannah River Site
Role of neurokinin B in the control of female puberty and Its modulation by metabolic status
[Abstract] Human genetic studies have revealed that neurokinin B (NKB) and its receptor, neurokinin-3 receptor (NK3R), are essential elements for normal reproduction; however, the precise role of NKBâNK3R signaling in the initiation of puberty remains unknown. We investigated here the regulation of Tac2 and Tacr3 mRNAs (encoding NKB and NK3R, respectively) in female rats and demonstrated that their hypothalamic expression is increased along postnatal maturation. At puberty, both genes were widely expressed throughout the brain, including the lateral hypothalamic area and the arcuate nucleus (ARC)/medial basal hypothalamus, where the expression of Tacr3 increased across pubertal transition. We showed that central administration of senktide (NK3R agonist) induced luteinizing hormone (LH) secretion in prepubertal and peripubertal females. Conversely, chronic infusion of an NK3R antagonist during puberty moderately delayed the timing of vaginal opening (VO) and tended to decrease LH levels. The expression of NKB and its receptor was sensitive to changes in metabolic status during puberty, as reflected by a reduction in Tacr3 (and, to a lesser extent, Tac2) expression in the ARC after a 48 h fast. Yet, acute LH responses to senktide in pubertal females were preserved, if not augmented, under fasting conditions, suggesting sensitization of the NKBâNK3Râgonadotropin-releasing hormone signaling pathway under metabolic distress. Moreover, repeated administration of senktide to female rats with pubertal arrest due to chronic undernutrition rescued VO (in âŒ50% of animals) and potently elicited LH release. Altogether, our observations suggest that NKBâNK3R signaling plays a role in pubertal maturation and that its alterations may contribute to pubertal disorders linked to metabolic stress and negative energy balance.Ministerio de Ciencia e InnovaciĂłn; BFU 2008-00984Ministerio de Ciencia e InnovaciĂłn; BFU 2011-25021AndalucĂa. Junta, P08-CVI-0060
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