23,736 research outputs found
Sub-Poissonian Shot Noise In A Diffusive Conductor
A review is given of the shot-noise properties of metallic, diffusive
conductors. The shot noise is one third of the Poisson noise, due to the
bimodal distribution of transmission eigenvalues. The same result can be
obtained from a semiclassical calculation. Starting from Oseledec's theorem it
is shown that the bimodal distribution is required by Ohm's law.Comment: 9 pages, LaTeX, including 2 figure
Doubled Shot Noise In Disordered Normal-Metal-Superconductor Junctions
The low-frequency shot-noise power of a normal-metal-superconductor junction
is studied for arbitrary normal region. Through a scattering approach, a
formula is derived which expresses the shot-noise power in terms of the
transmission eigenvalues of the normal region. The noise power divided by the
current is enhanced by a factor two with respect to its normal-state value, due
to Cooper-pair transport in the superconductor. For a disordered normal region,
it is still smaller than the Poisson noise, as a consequence of noiseless open
scattering channels.Comment: 4 pages, RevTeX v3.0, including 1 figure, Submitted to Physical
Review
THE EFFECTS OF INTERNAL AND EXTERNAL FOCUS ATTENTION ON THE STANDING LONG JUMP AMONG HIGH SCHOOL FEMALE ATHLETES
Coaches and trainers often use verbal cues to help players improve their sport performance and training quality. The type of verbal instructions implemented by a coach may influence how players execute certain tasks. External and internal focus attention are verbal ques that may help athletes improve performance in various tasks such as running and jumping. Purpose: This study attempted to determine if implementing external focus attention ques (EFAQ) improved standing long jump (SLJ) performance when compared to implementing internal focus attention ques (IFAQ). Methods: Female (n=14) high school soccer players completed three testing sessions where three trials of the SLJ were collected (3 sessions with 3 trials each). Prior to each testing session a dynamic warmup was implemented to prepare the participants for the subsequent SLJ trials. During the initial test session, the coach/investigator provided no attention ques (NQ) prior to the SLJ trials. During the other two testing sessions the coach provided either an EFAQ or IFAQ prior to the SLJ trials. Second and third testing session were carried out in a randomized repeated measures fashion. The testing sessions occurred on three different days at the beginning of the week over three weeks. The best SLJ score from each testing session was used for statistical analysis. A paired t-test was used to compare the SLJ scores between the sessions. Gain scores and effect size (EF) differences between the NQ SLJ scores and the EFAQ and IFAQ conditions were also calculated. Results: The best SLJ scores for the test conditions were as follows: NQ=174.0±17.4, IFAQ=169.1±20.7 and EFAQ=178.2±16.4 (cms). The EFAQ SLJ scores were significantly greater than both the IFAQ and NQ SLJ scores (p<0.05). The IFAQ SLJ scores were significantly less than the NQ SLJ scores (p<0.05). The ES difference and gain score between the EFAQ and NQ were: 0.24 SD and 4.2±7.3 cms. The ES difference and gain score between the IFAQ and NQ were: -0.28 SD and -4.9±10.0 cms. Conclusion: Within the parameters of this study, EFAQ improves SLJ scores when compared to either NQ or IFAQ scenarios. Further, IFAQ appears to degrade SLJ performance when compared to a NQ scenario. Article visualizations
Immunity in barren and enriched housed pigs differing in baseline cortisol concentration
It was shown recently that barren housed pigs (small pens, no substrate) have a blunted circadian rhythm of salivary cortisol as compared to enriched housed pigs (large pens with daily fresh bedding). In the light period, enriched housed pigs showed significantly higher concentrations of cortisol in saliva than barren housed pigs, whereas in the dark period, cortisol concentrations were low in both enriched and barren housed pigs. In the present study, the immunological consequences of the difference in baseline salivary cortisol concentration in the light period were evaluated. It appeared that leukocyte and lymphocyte distributions, and in vitro lymphocyte proliferation following ConcanavalineA (ConA) stimulation in the assay using purified lymphocytes were not affected. However, barren and enriched housed pigs did show a different proliferation response to ConA in the whole blood assay. At day 2 of culture, proliferation was higher in barren housed pigs than in enriched housed pigs, whereas at day 4 of culture, proliferation was higher in enriched housed pigs than in barren housed pigs. Lymphocyte proliferation at day 2 of culture in the whole blood assay correlated negatively with plasma cortisol levels, which might thus explain the higher proliferation in barren housed pigs at day 2 of culture. The in vivo humoral and cellular (delayed type hypersensitivity, DTH) immune response to KLH was not affected by housing conditions. We conclude that, although baseline salivary cortisol concentrations differ between enriched and barren housed pigs, immune function appears to be relatively unaffected.
A Look At Three Different Scenarios for Bulge Formation
In this paper, we present three qualitatively different scenarios for bulge
formation: a secular evolution model in which bulges form after disks and
undergo several central starbursts, a primordial collapse model in which bulges
and disks form simultaneously, and an early bulge formation model in which
bulges form prior to disks. We normalize our models to the local z=0
observations of de Jong & van der Kruit (1994) and Peletier & Balcells (1996)
and make comparisons with high redshift observations. We consider model
predictions relating directly to bulge-to-disk properties. As expected, smaller
bulge-to-disk ratios and bluer bulge colors are predicted by the secular
evolution model at all redshifts, although uncertainties in the data are
currently too large to differentiate strongly between the models.Comment: 19 pages, 6 figures, accepted for publication in the Astrophysical
Journa
Bariatric surgery in young adults:A multicenter study into weight loss, dietary adherence, and quality of life
Background: Numerous studies have demonstrated that bariatric surgery is an effective intervention for morbid obesity, but study samples are characterized by an underrepresentation of young adult patients.Objectives: The aim of this study was to evaluate weight loss, dietary adherence, and quality of life (QoL) in a multicenter, young adult sample, in the first 6 years after bariatric surgery.Setting: Four general hospitals in the Netherlands.Methods: A total of 184 young adult patients who underwent bariatric surgery between 6 and 74 months previously at the age of 18 to 24 years were included, interviewed by phone, and sent questionnaires assessing postoperative weight, QoL, and lifestyle behaviors including dietary adherence. Complete data were available for those 96 patients who returned the questionnaires.Results: Mean percent weight loss was 30.2 (SD 10.7) for laparoscopic sleeve gastrectomy and 35.6 (SD 6.9) for laparoscopic Roux-en-Y gastric bypass. Adherence to postoperative dietary recommendations declined over the years (r = .25, P = .02) and explained 8.3% of the variance in weight loss (r = .29, P = .005). QoL scores lagged behind national norms for young adults and were largely unrelated to weight loss. A quarter of patients (25%) turned out to be not in education, employment, or training and 38% had used mental healthcare services since surgery, which occurred independent of weight loss and concurred with poorer QoL.Conclusion: Young adult patients achieve weight loss comparable to adult patients after bariatric surgery. However, postoperative adherence to behavioral recommendations and psychosocial functioning clearly demonstrate room for improvement and require adjunctive interventions.</p
Effect of different injection routes in tumor accumulation and biodistribution of radiolabeled Pluronic P94 unimers
Gasification of woody biomass in a novel indirectly heated bubbling fluidized bed steam reformer
Within this work, a novel 50 kWth indirectly heated bubbling fluidized bed steam reformer (IHBFBSR) is presented, along with its commissioning experiments. In the IHBFBSR, heat is provided through two radiant tube natural gas burners in the bed and the freeboard area. The aim of this innovative design is sufficient heat provision for biomass steam reforming and cracking reactions and heat loss reduction, thus allowing the possibility of scaling-up to an industrial level. Experiments were performed with two woody biomass feedstocks and two bed material particle sizes under different operating conditions (steam to biomass ratio, lambda, temperature), in order to identify the setup's main characteristics. Product gas composition and quality, as well as the cold gas efficiency of the IHBFBSR were in reasonable agreement to similar systems, however carbon conversion prediction needs further improvement. H2 production and tar removal are favoured by small bed material particle sizes as well as by char accumulation in the bed area. Furthermore, air injection above the bed led to improved H2/CO ratios and lower tar yields compared to when air is used as a fluidization agent. Overall, it was shown that the IHBFBSR technology constitutes a promising development in the field of biomass allothermal gasification.Large Scale Energy Storag
Quartic double solids with ordinary singularities
We study the mixed Hodge structure on the third homology group of a threefold
which is the double cover of projective three-space ramified over a quartic
surface with a double conic. We deal with the Torelli problem for such
threefolds.Comment: 14 pages, presented at the Conference Arnol'd 7
On modelling and stabilizability of voltage-controlled piezoelectric material
In this paper, we present a new piezoelectric actuator and piezoelectric
composite model and show the well-posedness of these systems. Furthermore, we
show that the piezoelectric composite is stabilizable for certain system
parameters. In this work, we also review several piezoelectric beams,
actuators, and composite models and provide improved definitions of the
different electromagnetic considerations, i.e. fully dynamic electromagnetic
field, quasi-static electric field, and the static lectric field assumption.Comment: 19 pages, 5 figures, 2 tables. This work is intended to be submitted
for possible publication. Copyright may be transferred without notice, after
which this version may no longer be accessibl
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