2,146 research outputs found
The coastal environmental profile of Ban Don Bay and Phangnga Bay, Thailand
Environmental profile, Coastal zone management, Coastal zone, Ban Don Bay, Phangnga Bay, Thailand, Environmental Economics and Policy,
Differential Effects of Oral vs. Intravenous Fluid Administration on Bioelectrical Impedance During Dehydration Induced by Exercise and Heat
There is continued debate regarding optimal evaluation of hydration. Bioimpedance analysis has been utilized to evaluate hydration status, but there is limited information regarding the ability of this technology to detect physiological changes occurring during acute dehydration. PURPOSE: To evaluate whether bioimpedance spectroscopy (BIS) detects changes in bioelectrical resistance (R) in response to dehydration induced by exercising in the heat, assess whether these changes are related to body mass changes, and determine if the route of fluid administration during the dehydration protocol influences these observations. METHODS: Twelve males (mean ± SD; age: 28.6 ± 12.4 y; body mass: 74.7 ± 7.9 kg; height: 179.4 ± 7.0 cm; VO2max: 49.8 ± 6.6 mL/kg/min) completed two randomized experimental trials, each consisting of 90 minutes of continuous cycling exercise at 55% VO2maxfollowed by a 12 km time trial in the heat (ambient temperature: 34.9 ± 0.6 °C; relative humidity: 30.3 ± 0.9 %; wind speed: 3.4 mile×h-1). During each trial, fluid was administered either orally (DRINK) or intravenously (IV). During the DRINK trial, participants drank 25 mL of water every 5 minutes. During the IV trial, participants received 25 mL of isotonic saline solution through their IV catheter every 5 minutes. Nude body mass and BIS data were collected before and after trials to assess hydration status. Data were analyzed using Pearson’s correlations and paired t-tests with p-values corrected via false discovery rate. RESULTS: Body mass decreased, without differences between conditions (IV: -2.3 ± 0.5%; DRINK: -2.4 ± 0.9%; p=0.85). However, significant differences were observed for changes in predicted R at zero frequency (R0; IV: -3.6 ± 4.6%; DRINK: 1.3 ± 5.6%; p=0.02) and R at 50 kHz (R50; IV: -3.2 ± 4.1%; DRINK: -0.2 ± 4.1%; p=0.04), without differences in predicted R at infinite frequency (R∞; IV: -2.4 ± 6.1%; DRINK: -1.1 ± 3.7%; p=0.45). In the IV condition, significant correlations between body mass changes and R changes were observed for R0 (r=-0.80; p=0.002), R50 (r=-0.85; p\u3c0.001), and R∞ (r=-0.84; p\u3c0.001); however, no correlations were observed in the DRINK condition (r=-0.06 to 0.13; p≥0.69 for each). CONCLUSION: Differences between oral and intravenous fluid administration were seemingly detected by bioelectrical resistance at low-to-moderate, but not high, frequencies. With intravenous administration, negative correlations between changes in body mass and changes in R at all frequencies were observed, unlike with oral fluid administration. These findings suggest a potential sensitivity of bioimpedance technologies for monitoring intravenous fluid administration in the context of acute dehydration. However, additional investigation is needed to confirm their utility during distinct fluid loss scenarios and to confirm if these technologies are useful in the context of oral intake of fluids varying in composition
Genetics and Gene Expression Involving Stress and Distress Pathways in Fibromyalgia with and without Comorbid Chronic Fatigue Syndrome
In complex multisymptom disorders like fibromyalgia syndrome (FMS) and chronic fatigue syndrome (CFS) that are defined primarily by subjective symptoms, genetic and gene expression profiles can provide very useful objective information. This paper summarizes research on genes that may be linked to increased susceptibility in developing and maintaining these disorders, and research on resting and stressor-evoked changes in leukocyte gene expression, highlighting physiological pathways linked to stress and distress. These include the adrenergic nervous system, the hypothalamic-pituitary-adrenal axis and serotonergic pathways, and exercise responsive metabolite-detecting ion channels. The findings to date provide some support for both inherited susceptibility and/or physiological dysregulation in all three systems, particularly for catechol-O-methyl transferase (COMT) genes, the glucocorticoid and the related mineralocorticoid receptors (NR3C1, NR3C2), and the purinergic 2X4 (P2X4) ion channel involved as a sensory receptor for muscle pain and fatigue and also in upregulation of spinal microglia in chronic pain models. Methodological concerns for future research, including potential influences of comorbid clinical depression and antidepressants and other medications, on gene expression are also addressed
A high specific power solar array for low to mid-power spacecraft
UltraFlex is the generic term for a solar array system which delivers on-orbit power in the 400 to 6,000 watt per wing sizes with end-of-life specific power performance ranging to 150 watts-per-kilogram. Such performance is accomplished with off-the-shelf solar cells and state-of the-art materials and processes. Much of the recent work in photovoltaics is centered on advanced solar cell development. Successful as such work has been, no integrated solar array system has emerged which meets NASA's stated goals of 'increasing the end-of-life performance of space solar cells and arrays while minimizing their mass and cost.' This issue is addressed; namely, is there an array design that satisfies the usual requirements for space-rated hardware and that is inherently reliable, inexpensive, easily manufactured and simple, which can be used with both advanced cells currently in development and with inexpensive silicon cells? The answer is yes. The UltraFlex array described incorporates use of a blanket substrate which is thermally compatible with silicon and other materials typical of advanced multi-junction devices. The blanket materials are intrinsically insensitive to atomic oxygen degradation, are space rated, and are compatible with standard cell bonding processes. The deployment mechanism is simple and reliable and the structure is inherently stiff (high natural frequency). Mechanical vibration modes are also readily damped. The basic design is presented as well as supporting analysis and development tests
Discovery of Extremely Embedded X-ray Sources in the R Coronae Australis Star Forming Core
With the XMM-Newton and Chandra observatories, we detected two extremely
embedded X-ray sources in the R Corona Australis (R CrA) star forming core,
near IRS 7. These sources, designated as XB and XA, have X-ray absorption
columns of ~3e23 cm-2 equivalent to AV ~180 mag. They are associated with the
VLA centimeter radio sources 10E and 10W, respectively. XA is the counterpart
of the near-infrared source IRS 7, whereas XB has no K-band counterpart above
19.4 mag. This indicates that XB is younger than typical Class I protostars,
probably a Class 0 protostar or in an intermediate phase between Class 0 and
Class I. The X-ray luminosity of XB varied between 29<log LX <31.2 ergs s-1 on
timescales of 3-30 months. XB also showed a monotonic increase in X-ray
brightness by a factor of two in 30 ksec during an XMM-Newton observation. The
XMM-Newton spectra indicate emission from a hot plasma with kT ~3-4 keV and
also show fluorescent emission from cold iron. Though the X-ray spectrum from
XB is similar to flare spectra from Class I protostars in luminosity and
temperature, the light curve does not resemble the lightcurves of magnetically
generated X-ray flares because the variability timescale of XB is too long and
because variations in X-ray count rate were not accompanied by variations in
spectral hardness. The short-term variation of XB may be caused by the partial
blocking of the X-ray plasma, while the month-long flux enhancement may be
driven by mass accretion.Comment: 26 pages, 8 figures, To be published in ApJ in April 200
Chirality Violation in QCD Reggeon Interactions
The appearance of the triangle graph infra-red axial anomaly in reduced quark
loops contributing to QCD triple-regge interactions is studied. In a dispersion
relation formalism, the anomaly can only be present in the contributions of
unphysical triple discontinuities. In this paper an asymptotic discontinuity
analysis is applied to high-order feynman diagrams to show that the anomaly
does indeed occur in sufficiently high-order reggeized gluon interactions. The
reggeon states involved must contain reggeized gluon combinations with the
quantum numbers of the anomaly (winding-number) current. A direct connection
with the well-known U(1) problem is thus established. Closely related diagrams
that contribute to the pion/pomeron and triple pomeron couplings in color
superconducting QCD are also discussed.Comment: 52 pages, 29 PS figures in the tex
Development and Reliability of a Measure of Clinician Competence in Providing Illness Management and Recovery
Objective: Illness management and recovery (IMR) is an evidence-based, manualized illness self-management program for people with severe mental illness. This study sought to develop a measure of IMR clinician competence and test its reliability and validity.
Methods: Two groups of subject matter experts each independently created a clinician-level IMR competence scale based on the IMR Fidelity Scale and on two unpublished instruments used to evaluate provider competence. The two versions were merged, and investigators used the initial version to independently rate recordings of IMR sessions. Ratings were compared and discussed, discrepancies were resolved, and the scale was revised through 14 iterations. The resulting IMR Treatment Integrity Scale (IT-IS) includes 13 required items and three optional items rated only when the particular skill is attempted. Four independent raters then used the IT-IS to score tapes of 60 IMR sessions and 20 control group sessions.
Results: The IT-IS showed excellent interrater reliability (.92). A factor analysis supported a one-factor model that showed good internal consistency. The scale successfully differentiated between IMR and control groups. Reliability and validity of individual items varied widely.
Conclusions: The IT-IS is a promising measure of clinician competence in providing IMR. The scale could be used for research and quality assurance and as a supervisory feedback tool. Future research is needed to examine item-level changes, predictive validity of the IT-IS, discriminant validity compared with other more structured interventions, and the reliability and validity of the scale for nongroup IMR
Adjusting bone mass for differences in projected bone area and other confounding variables: an allometric perspective.
The traditional method of assessing bone mineral density (BMD; given by bone mineral content [BMC] divided by projected bone area [Ap], BMD = BMC/Ap) has come under strong criticism by various authors. Their criticism being that the projected bone "area" (Ap) will systematically underestimate the skeletal bone "volume" of taller subjects. To reduce the confounding effects of bone size, an alternative ratio has been proposed called bone mineral apparent density [BMAD = BMC/(Ap)3/2]. However, bone size is not the only confounding variable associated with BMC. Others include age, sex, body size, and maturation. To assess the dimensional relationship between BMC and projected bone area, independent of other confounding variables, we proposed and fitted a proportional allometric model to the BMC data of the L2-L4 vertebrae from a previously published study. The projected bone area exponents were greater than unity for both boys (1.43) and girls (1.02), but only the boy's fitted exponent was not different from that predicted by geometric similarity (1.5). Based on these exponents, it is not clear whether bone mass acquisition increases in proportion to the projected bone area (Ap) or an estimate of projected bone volume (Ap)3/2. However, by adopting the proposed methods, the analysis will automatically adjust BMC for differences in projected bone size and other confounding variables for the particular population being studied. Hence, the necessity to speculate as to the theoretical value of the exponent of Ap, although interesting, becomes redundant
Beyond Electronics
Amundson traces the histories of electronic technologies, video, and electronic art, examining the shift from art about the technology itself to work that uses it as an expressive tool or addresses its social dimension. Lists exhibitions related to art and technology. Statements by 11 artists. Biographical notes. 14 bibl. ref
The Relationship Between Provider Competence, Content Exposure, and Consumer Outcomes in Illness Management and Recovery Programs
Provider competence may affect the impact of a practice. The current study examined this relationship in sixty-three providers engaging in Illness Management and Recovery with 236 consumers. Improving upon previous research, the present study utilized a psychometrically validated competence measure in the ratings of multiple Illness Management and Recovery sessions from community providers, and mapped outcomes onto the theory underlying the practice. Provider competence was positively associated with illness self-management and adaptive coping. Results also indicated baseline self-management skills and working alliance may affect the relationship between competence and outcomes
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