1,892 research outputs found
High angular resolution observation of the Sunyaev-Zel'dovich effect in the massive z=0.83 cluster ClJ0152-1357
X-ray observations of galaxy clusters at high redshift (z>0.5) indicate that
they are more morphologically complex and less virialized than those at
low-redshift. We present the first subarcmin resolution at 18 GHz observations
of the Sunyaev-Zel'dovich (SZ) effect for ClJ0152-1357 using the Australia
Telescope Compact Array. ClJ0152-1357 is a massive cluster at redshift z=0.83
and has a complex structure including several merging subclumps which have been
studied at optical, X-ray, and radio wavelengths. Our high-resolution
observations indicate a clear displacement of the maximum SZ effect from the
peak of X-ray emission for the most massive sub-clump. This result shows that
the cluster gas within the cluster substructures is not virialised in
ClJ0152-1357 and we suggest that it is still recovering from a recent merger
event. A similar offset of the SZ effect has been recently seen in the `bullet
cluster' by Malu et al. This non-equilibrium situation implies that high
resolution observations are necessary to investigate galaxy cluster evolution,
and to extract cosmological constraints from a comparison of the SZ effect and
X-ray signals.Comment: 5 pages, 4 figures, submitted to ApJ
Application of ERTS-1 imagery to the harvest model of the US Menhaden fishery
Preliminary results of an experiment to demonstrate the utility of ERTS-1 imagery for providing significant information to the harvest model of the menhaden industry are reported. Fisheries and related environmental data were obtained discontinuously throughout the 1973 menhaden (a surface schooling, coastal species) fishing season in Mississippi Sound. The unexpected complexity of the physical environment in Mississippi Sound precluded simplistic analysis of fish/environment relationships. Preliminary indications are that an association does exist between fish availability and differences in water transparency (turbidity) within the Sound. A clearer relationship is developing between major turbid features, imaged by ERTS-1 and location of successful fishing attempts. On all occasions where relatively cloudfree ERTS-1 overflight days coincided with fishery activity, overlays of catch location of ERTS-1 images show an association of school position with interfaces between imaged turbid features. Analysis is currently underway to determine persistence of such associations in an attempt to define minimum satellite return time necessary to maintain continuity of associations
Dairy herd recording
Fifty-five percent or 320 of Western Australia\u27s daity farmers participate in the dairy herd recording, the highest percentage of dairy farmers who use herd recording in any Australian State.
Herd recording provides the dairy farmer with an accurate measure and record of individual caw and hers performance. Information on milk, fat and protein production, the level of mastitis infection and breeding values assists the dairy farmer with his herd management and selection of cows. The herd recording facility is provided by the Herd Improvement Service and the fees are based on an annual herd fee and a lactation fee for each cow
Airborne Effluent Monitoring System Certification for New B-Plant Ventilation Exhaust Stack
Not in education, employment and training: pathways from toddler difficult temperament
Background:
Youths disengaged from the education system and labour force (i.e. âNot in Education, Employment, or Trainingâ or âNEETâ) are often at reduced capacity to flourish and thrive as adults. Developmental precursors to NEET status may extend back to temperamental features, though this â and possible mediators of such associations such as attention deficit hyperactivity (ADHD) symptoms and antisocial behaviours (ASB) â have yet to be directly tested. This study investigates if i) difficult temperament in toddlerhood associates with NEET status in adulthood and ii) different subdomains of ADHD (i.e. hyperactivity-impulsivity vs. inattention) in late childhood and ASB in adolescence partially explain this pathway.
Methods:
Participants were 6,240 mother-child dyads (60.7% female) from the Avon Longitudinal Study of Parents and Children. Mothers reported on their childâs (a) difficult temperament (i.e. mood, intensity and adaptability) at age 2 and (b) ADHD symptoms at ages 8 and 10. Participants reported their own ASB at age 14 and NEET status in adulthood (ages 18, 20, 22 and 23).
Results:
First, higher levels of difficult temperament in toddlerhood directly associated with an increased probability of being NEET in adulthood. Second, this effect was carried through hyperactivity-impulsivity, but not inattention, in late childhood, and ASB in adolescence; this demonstrates differential contribution to the pathway between the ADHD dimensions, with symptoms of hyperactivity-impulsivity playing a prominent role.
Conclusions:
Early difficult temperament is a vulnerability factor for NEET status in adulthood. Our findings suggest that one developmental pathway for this vulnerability manifests through increased hyperactivity-impulsivity in childhood and ASB in adolescence. Of note, difficult temperament, as measured here, reflects difficulties in emotional and behavioural self-control (e.g. low adaptability and high intensity negative emotional expressions). Our results, therefore, suggest a prominent developmental role for lack of self-control from toddlerhood onwards in increasing risk for NEET
Separating the BL Lac and Cluster X-ray Emissions in Abell 689 with Chandra
We present the results of a Chandra observation of the galaxy cluster Abell
689 (z=0.279). Abell 689 is one of the most luminous clusters detected in the
ROSAT All Sky Survey (RASS), but was flagged as possibly including significant
point source contamination. The small PSF of the Chandra telescope allows us to
confirm this and separate the point source from the extended cluster X-ray
emission. For the cluster we determine a bolometric luminosity of
L_{bol}=(3.3+/-0.3)x10^{44} erg s-1 and a temperature of kT=5.1^{+2.2}_{-1.3}
keV when including a physically motivated background model. We compare our
measured luminosity for A689 to that quoted in the Rosat All Sky Survey (RASS)
and find L_{0.1-2.4,keV}=2.8x10^{44} erg s-1, a value \sim10 times lower than
the ROSAT measurement. Our analysis of the point source shows evidence for
significant pileup, with a pile-up fraction of ~60%. SDSS spectra and HST
images lead us to the conclusion that the point source within Abell 689 is a BL
Lac object. Using radio and optical observations from the VLA and HST archives,
we determine {\alpha}_{ro}=0.50, {\alpha}_{ox}=0.77 and {\alpha}_{rx}=0.58 for
the BL Lac, which would classify it as being of 'High-energy peak BL Lac' (HBL)
type. Spectra extracted of A689 show a hard X-ray excess at energies above 6
keV that we interpret as inverse Compton emission from aged electrons that may
have been transported into the cluster from the BL Lac.Comment: 11 pages, 15 figures, MNRAS in pres
Carbohydrate, protein and fat metabolism during exercise after oral carnitine supplementation in humans
Twenty non-vegetarian active males were pair-matched and randomly assigned to receive 2 g L-Carnitine L-tartrate (LC).d-1 or placebo for 2 weeks. Subjects exercised for 90 min at 70% O2max following 2 days of a prescribed diet (mean ± SD: 13.6 ± 1.6 MJ, 57% carbohydrate, 15% protein, 26% fat, 2% alcohol) before and after supplementation. Results indicated no change in carbohydrate oxidation, nitrogen excretion, branched-chain amino acid oxidation, or plasma urea during exercise between the beginning and end of supplementation in either group. Following 2 weeks LC supplementation the plasma ammonia response to exercise tended to be suppressed (0 vs. 2wk at 60 min exercise: 97 ± 26 vs. 80 ± 9; and 90 min exercise: 116 ± 47 vs. 87 ± 25 ”mol.L-1), with no change in the placebo group. The data indicate that 2 weeks of LC supplementation does not affect fat, carbohydrate and protein contribution to metabolism during prolonged moderate intensity cycling exercise. However, the tendency towards suppressed ammonia accumulation indicates that oral LC supplementation may have the potential to reduce the metabolic stress of exercise or alter ammonia production/removal which warrants further investigation
Effects of exercise intensity and altered substrate availability on cardiovascular and metabolic responses to exercise after oral carnitine supplementation in athletes
The effects of 15 d of supplementation with L-carnitine L-tartrate (LC) on metabolic responses to graded-intensity exercise under conditions of altered substrate availability were examined. Fifteen endurance-trained male athletes undertook exercise trials after a 2-d high-carbohydrate diet (60% CHO, 25% fat) at baseline (D0), on Day 14 (D14), and after a single day of high fat intake (15% CHO, 70% fat) on Day 15 (D15) in a double-blind, placebo-controlled, pair-matched design. Treatment consisted of 3 g LC (2 g L-carnitine/d; n = 8) or placebo (P, n = 7) for 15 d. Exercise trials consisted of 80 min of continuous cycling comprising 20-min periods at each of 20%, 40%, 60%, and 80% VO2peak. There was no significant difference between whole-body rates of CHO and fat oxidation at any workload between D0 and D14 trials for either the P or LC group. Both groups displayed increased fat and reduced carbohydrate oxidation between the D14 and D15 trials (p less than .05). During the D15 trial, heart rate (p less than .05 for 20%, 40%, and 60% workloads) and blood glucose concentration (p less than .05 for 40% and 60% workloads) were lower during exercise in the LC group than in P. These responses suggest that LC may induce subtle changes in substrate handling in metabolically active tissues when fatty-acid availability is increased, but it does not affect whole-body substrate utilization during short-duration exercise at the intensities studied
The WARPS Survey. VIII. Evolution of the Galaxy Cluster X-ray Luminosity Function
We present measurements of the galaxy cluster X-ray Luminosity Function (XLF)
from the Wide Angle ROSAT Pointed Survey (WARPS) and quantify its evolution.
WARPS is a serendipitous survey of the central region of ROSAT pointed
observations and was carried out in two phases (WARPS-I and WARPS-II). The
results here are based on a final sample of 124 clusters, complete above a flux
limit of 6.5 10E-15 erg/s/cm2, with members out to redshift z ~ 1.05, and a sky
coverage of 70.9 deg2. We find significant evidence for negative evolution of
the XLF, which complements the majority of X-ray cluster surveys. To quantify
the suggested evolution, we perform a maximum likelihood analysis and conclude
that the evolution is driven by a decreasing number density of high luminosity
clusters with redshift, while the bulk of the cluster population remains nearly
unchanged out to redshift z ~ 1.1, as expected in a low density Universe. The
results are found to be insensitive to a variety of sources of systematic
uncertainty that affect the measurement of the XLF and determination of the
survey selection function. We perform a Bayesian analysis of the XLF to fully
account for uncertainties in the local XLF on the measured evolution, and find
that the detected evolution remains significant at the 95% level. We observe a
significant excess of clusters in the WARPS at 0.1 < z < 0.3 and LX ~ 2 10E42
erg/s compared with the reference low-redshift XLF, or our Bayesian fit to the
WARPS data. We find that the excess cannot be explained by sample variance, or
Eddington bias, and is unlikely to be due to problems with the survey selection
function.Comment: 13 pages, 12 figures, accepted for publication in MNRA
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Mentoring Among Scientists: Implications of Interpersonal Relationships within a Formal Mentoring Program
Mentoring is an established strategy for learning that has its root in antiquity. Most, if not all, successful scientists and engineers had an effective mentor at some point in their career. In the context of scientists and engineers, mentoring has been undefined. Reports addressing critical concerns regarding the future of science and engineering in the U.S. mention the practice of mentoring a priori, leaving organizations without guidance in its application. Preliminary results from this study imply that formal mentoring can be effective when properly defined and operationalized. Recognizing the uniqueness of the individual in a symbiotic mentor-protĂ©gĂ© relationship significantly influences a protĂ©gĂ©âs learning experience which carries repercussions into their career intentions. The mentor-protĂ©gĂ© relationship is a key factor in succession planning and preserving and disseminating critical information and tacit knowledge essential to the development of leadership in the science and technological industry
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