2,198 research outputs found
Probing the IGM/Galaxy Connection IV: The LCO/WFCCD Galaxy Survey of 20 Fields Surrounding UV Bright Quasars
We publish the survey for galaxies in 20 fields containing ultraviolet bright
quasars (with z_em 0.1 to 0.5) that can be used to study the association
between galaxies and absorption systems from the low-z intergalactic medium
(IGM). The survey is magnitude limited (R~19.5 mag) and highly complete out to
10' from the quasar in each field. It was designed to detect dwarf galaxies (L
~ 0.1 L*) at an impact parameter rho 1Mpc (z=0.1) from a quasar. The complete
sample (all 20 fields) includes R-band photometry for 84718 sources and
confirmed redshifts for 2800 sources. This includes 1198 galaxies with 0.005 <
z < (z_em - 0.01) at a median redshift of 0.18, which may associated with IGM
absorption lines. All of the imaging was acquired with cameras on the Swope 40"
telescope and the spectra were obtained via slitmask observations using the
WFCCD spectrograph on the Dupont 100" telescope at Las Campanas Observatory
(LCO). This paper describes the data reduction, imaging analysis, photometry,
and spectral analysis of the survey. We tabulate the principal measurements for
all sources in each field and provide the spectroscopic dataset online.Comment: Accepted to the Astrophysical Journal Supplements; 20 pages, only 6
figures shown in this version. See
http://www.ucolick.org/~xavier/WFCCDOVI/index.html for a full-length
manuscript and other supportive materia
Comparison of fibre optical measurements and discrete element simulations for the study of granulation in a spout fluidized bed
Spout fluidized beds are frequently used for the production of granules or particles through granulation. The products find application in a large variety of applications, for example detergents, fertilizers, pharmaceuticals and food. Spout fluidized beds have a number of advantageous properties, such as a high mobility of the particles, which prevents undesired agglomeration and yields excellent heat transfer properties. The particle growth mechanism in a spout fluidized bed as function of particle-droplet interaction has a profound influence on the particle morphology and thus on the product quality. Nevertheless, little is known about the details of the granulation process. This is mainly due to the fact that the granulation process is not visually accessible. In this work we use fundamental, deterministic models to enable the detailed investigation of granulation behaviour in a spout fluidized bed. A discrete element model is used describing the dynamics of the continuous gas-phase and the discrete droplets and particles. For each element momentum balances are solved. The momentum transfer among each of the three phases is described in detail at the level of individual elements. The results from the discrete element model simulations are compared with local measurements of particle volume fractions as well as particle velocities by using a novel fibre optical probe in a fluidized bed of 400 mm I.D. Simulations and experiments were carried out for three different cases using Geldart B type aluminium oxide particles: a freely bubbling fluidized bed; a spout fluidized bed without the presence of droplets and a spout fluidized bed with the presence of droplets. It is demonstrated how the discrete element model can be used to obtain information about the interaction of the discrete phases, i.e. the growth zone in a spout fluidized bed. Eventually this kind of information can be used to obtain closure information required in more coarse grained models
The Acute Effects of Whole Body Vibration on Muscular Power and Agility
Context: While research suggests whole body vibration (WBV) positively affects measures of neuromuscular performance in athletes, researchers have yet to address appropriate and effective vibration protocols.
Objective: To identify the acute effects of continuous and intermittent WBV on muscular power and agility in recreationally active females.
Design: We used a randomized 3-period cross-over design to observe the effects of 3 vibration protocols on muscular power and agility.
Setting: Sports Science and Medicine Research Laboratory at Florida International University.
Patients or Other Participants: Eleven recreationally active female volunteers (age=24.4±5.7y; ht=166.0±10.3cm; mass=59.7±14.3kg).
Interventions: Each session, subjects stood on the Galileo WBV platform (Orthometrix, White Plains, NY) and received one of three randomly assigned vibration protocols. Our independent variable was vibration length (continuous, intermittent, or no vibration).
Main Outcome Measures: An investigator blinded to the vibration protocol measured muscular power and agility. We measured muscular power with heights of squat and countermovement jumps. We measured agility with the Illinois Agility Test.
Results: Continuous WBV significantly increased SJ height from 97.9±7.6cm to 98.5±7.5cm (P=0.019, ÎČ=0.71, η2 =0.07) but not CMJ height [99.1±7.4cm pretest and 99.4±7.4cm posttest (P=0.167, ÎČ=0.27)] or agility [19.2±2.1s pretest and 19.0±2.1s posttest (P=0.232, ÎČ=0.21)]. Intermittent WBV significantly enhanced SJ height from 97.6±7.7cm to 98.5±7.7cm (P=0.017, ÎČ=0.71, η2 =0.11) and agility 19.4±2.2s to 19.0±2.1s (P=0.001, ÎČ=0.98, η2=0.16), but did not effect CMJ height [98.7±7.7cm pretest and 99.3±7.3cm posttest (P=0.058, ÎČ=0.49)].
Conclusion: Continuous WBV increased squat jump height, while intermittent vibration enhanced agility and squat jump height. Future research should continue investigating the effect of various vibration protocols on athletic performance
Pilot Implementation of a Heat Illness Prevention Program in the Southeastern US
Objective: To evaluate the ease of application of a heat illness prevention program (HIPP).
Design: A mixed-method research design was used: questionnaire and semi-structured interview.
Setting: Eleven South Florida high schools in August (mean ambient temperature=84.0°F, mean relative humidity=69.5%) participated in the HIPP.
Participants: Certified Athletic Trainers (AT) (n=11; age=22.2+1.2yr; 63.6% female, 36.4% male; 63.6%) implemented the HIPP with their football athletes which included a pre-screening tool, the Heat Illness Index Score- Risk Assessment.
Data Collection and Analysis: Participants completed a 17-item questionnaire, 4 of which provided space for open-ended responses. Additionally, semi-structured interviews were voice recorded, and separately transcribed.
Results: Three participants (27.7%) were unable to implement the HIPP with any of their athletes. Of the 7 participants (63.6%) who implemented the HIPP to greater than 50% of their athletes, a majority reported that the HIPP was difficult (54.5%) or exceedingly difficult (18.2%) to implement. Lack of appropriate instrumentation (81.8%, n=9/11), lack of coaching staff/administrative support (54.5%, n=6/11), insufficient support staff (54.5%, n=6/11), too many athletes (45.5%, n=5/11), and financial restrictions (36.4%, n=4/11) deterred complete implementation of the HIPP.
Conclusions: Because AT in the high school setting often lack the resources, time, and coachesâ support to identify risk factors, predisposing athletes to exertional heat Illnesses (EHI) researchers should develop and validate a suitable screening tool. Further, ATs charged with the health care of high school athletes should seek out prevention programs and screening tools to identify high-risk athletes and monitor athletes throughout exercise in extreme environments
Warm-Hot Gas in and around the Milky Way: Detection and Implications of OVII Absorption toward LMC X-3
X-ray absorption lines of highly-ionized species such as OVII at about zero
redshift have been firmly detected in the spectra of several active galactic
nuclei. However, the location of the absorbing gas remains a subject of debate.
To separate the Galactic and extragalactic contributions to the absorption, we
have obtained Chandra LETG-HRC and FUSE observations of the black hole X-ray
binary LMC X--3. A joint analysis of the detected OVII and Ne IX Kalpha lines,
together with the non-detection of the OVII Kbeta and OVIII Kalpha lines, gives
the measurements of the temperature, velocity dispersion, and hot oxygen column
density. The X-ray data also allow us to place a 95% confidence lower limit to
the Ne/O ratio as 0.14. The OVII line centroid and its relative shift from the
Galactic OI Kalpha absorption line, detected in the same observations, are
inconsistent with the systemic velocity of LMC X--3 ().
The far-UV spectrum shows OVI absorption at Galactic velocities, but no OVI
absorption is detected at the LMC velocity at significance. Both
the nonthermal broadening and the decreasing scale height with the increasing
ionization state further suggest an origin of the highly-ionized gas in a
supernova-driven galactic fountain. In addition, we estimate the warm and hot
electron column densities from our detected OVII Kalpha line in the LMC X--3
X-ray spectra and from the dispersion measure of a pulsar in the LMC vicinity.
We then infer the O/H ratio of the gas to be ,
consistent with the chemically-enriched galactic fountain scenario. We conclude
that the Galactic hot interstellar medium should in general substantially
contribute to zero-redshift X-ray absorption lines in extragalactic sources.Comment: 11 pages, accepted for publication in Ap
Late glacial palaeoclimate investigations at King Arthurâs Cave and Sun Hole Cave.
King Arthurâs Cave (Wye Valley) and Sun Hole Cave (Cheddar Gorge) currently provide the earliest dates for a human presence in the British Isles after the Last Glacial Maximum. The
earliest phase of activity at these sites has been dated to c. 15.2 to 14.6 thousand years cal. BP, which spans the onset of the Late Glacial Interstadial, a major global climate transition characterised by rapidly warming temperatures. Here we present stable isotope data from horse (Equus ferus) teeth found in the zooarchaeological assemblages at the sites. We also report two new radiocarbon dates on specimens from King Arthurâs Cave. The Equus tooth enamel provides a record of climatic conditions during the animalsâ tooth formation. Evidence
of human modification of the teeth (cut marks and fractures) chronologically tie these palaeoclimatic records to the earliest post-LGM archaeology at the two sites, thus informing on the climatic and environmental context under which human activity in these areas took place. Results indicate that people were present at the two sites during a period of climatic warming, with temperatures perhaps only marginally colder than present day conditions. However, suboptimal environmental conditions are suggested and may indicate changing
vegetation dynamics within the local landscape
The Case for an Accelerating Universe from Supernovae
The unexpected faintness of high-redshift Type Ia supernovae (SNe Ia), as
measured by two teams, has been interpreted as evidence that the expansion of
the Universe is accelerating. We review the current challenges to this
interpretation and seek to answer whether the cosmological implications are
compelling. We discuss future observations of SNe Ia which could offer
extraordinary evidence to test acceleration.Comment: To appear as an Invited Review for PASP 20 pages, 13 figure
The central conserved region (CCR) of respiratory syncytial virus (RSV) G protein modulates host miRNA expression and alters the cellular response to infection
Respiratory Syncytial Virus (RSV) infects respiratory epithelial cells and deregulates host gene expression by many mechanisms including expression of RSV G protein (RSV G). RSV G protein encodes a central conserved region (CCR) containing a CX3C motif that functions as a fractalkine mimic. Disruption of the CX3C motif (a.a. 182â186) located in the CCR of the G protein has been shown to affect G protein function in vitro and the severity of RSV disease pathogenesis in vivo. We show that infection of polarized Calu3 respiratory cells with recombinant RSV having point mutations in Cys173 and 176 (C173/176S) (rA2-GC12), or Cys186 (C186S) (rA2-GC4) is associated with a decline in the integrity of polarized Calu-3 cultures and decreased virus production. This is accompanied with downregulation of miRNAs let-7f and miR-24 and upregulation of interferon lambda (IFNλ), a primary antiviral cytokine for RSV in rA2-GC12/rA2-GC4 infected cells. These results suggest that residues in the cysteine noose region of RSV G protein can modulate IFN λ expression accompanied by downregulation of miRNAs, and are important for RSV G protein function and targeting
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Laboratory Evaluation of Underwater Grouting of CPP-603 Basins
A project is underway to deactivate a Fuel Storage Basin. The project specifies the requirements and identifies the tasks that will be performed for deactivation of the CPP- 603 building at the Idaho Nuclear Technology and Engineering Center of the Idaho National Engineering and Environmental Laboratory. The Fuel Receiving and Storage Building (CPP- 603) was originally used to receive and store spent nuclear fuel from various facilities. The area to undergo deactivation includes the three spent nuclear fuel storage basins and a transfer canal (1.5 million gallons of water storage). Deactivation operations at the task site include management of the hot storage boxes and generic fuel objects, removal of the fuel storage racks, basin sludge, water evaporation and basin grouting, and interior equipment, tanks, and associated components. This includes a study to develop a grout formulation and placement process for this deactivation project. Water will be allowed to passively evaporate to r educe the spread of contamination from the walls of the basin. The basins will be filled with grout, underwater, as the water evaporates to maintain the basin water at a safe level. The objective of the deactivation project is to eliminate potential exposure to hazardous and radioactive materials and eliminate potential safety hazards associated with the CPP-603 building
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