Pedometer-determined physical activity and active transport in girls

<p>Abstract</p> <p>Background</p> <p>It is well established that the risk of insufficient physical activity is greater in girls than in boys, especially during the adolescent years. The promotion of active transport (AT) to and from school has been posited as a practical and convenient solution for increasing girls' total daily activity. However, there is limited information describing the associations between AT choices and girls' physical activity across a range of age, ethnic, and socioeconomic groups. The objectives of this study were to (1) investigate physical activity patterns in a large multiethnic sample of female children and adolescents, and to (2) estimate the physical activity associated with AT to and from school.</p> <p>Methods</p> <p>A total of 1,513 girls aged 5–16 years wore sealed multiday memory (MDM) pedometers for three weekdays and two weekend days. The ethnic composition of this sample was 637 European (42.1%), 272 Pacific Island (18.0%), 207 East Asian (13.7%), 179 Maori (11.8%), 142 South Asian (9.4%), and 76 from other ethnic groups (5%). Pedometer compliance and school-related AT were assessed by questionnaire.</p> <p>Results</p> <p>Mean weekday step counts (12,597 ± 3,630) were higher and less variable than mean weekend steps (9,528 ± 4,407). A consistent decline in daily step counts was observed with age: after adjustment for ethnicity and SES, girls in school years 9–10 achieved 2,469 (weekday) and 4,011 (weekend) fewer steps than girls in years 1–2. Daily step counts also varied by ethnicity, with Maori girls the most active and South Asian girls the least active. Overall, 44.9% of participants used AT for school-related travel. Girls who used AT to and from school averaged 1,052 more weekday steps than those who did not use AT. However, the increases in steps associated with AT were significant only in older girls (school years 5–10) and in those of Maori or European descent.</p> <p>Conclusion</p> <p>Our data suggest that adolescent-aged girls and girls of Asian descent are priority groups for future physical activity interventions. While the apparent benefits of school-related AT vary among demographic groups, promoting AT in girls appears to be a worthwhile strategy.</p

Correlated radial velocity and X-ray variations in HD 154791/4U 1700+24

We present evidence for approximately 400-d variations in the radial velocity of HD 154791 (V934 Her), the suggested optical counterpart of 4U 1700+24. The variations are correlated with the previously reported approximately 400 d variations in the X-ray flux of 4U 1700+24, which supports the association of these two objects, as well as the identification of this system as the second known X-ray binary in which a neutron star accretes from the wind of a red giant. The HD 154791 radial velocity variations can be fit with an eccentric orbit with period 404 +/- 3 d, amplitude K=0.75 +/- 0.12 km/s and eccentricity e=0.26 +/- 0.15. There are also indications of variations on longer time scales >~ 2000 d. We have re-examined all available ASM data following an unusually large X-ray outburst in 1997-98, and confirm that the 1-d averaged 2-10 keV X-ray flux from 4U 1700+24 is modulated with a period of 400 +/- 20 d. The mean profile of the persistent X-ray variations was approximately sinusoidal, with an amplitude of 0.108 +/- 0.012 ASM count/s (corresponding to 31% rms). The epoch of X-ray maximum was approximately 40 d after the time of periastron according to the eccentric orbital fit. If the 400 d oscillations from HD 154791/4U 1700+24 are due to orbital motion, then the system parameters are probably close to those of the only other neutron-star symbiotic-like binary, GX 1+4. We discuss the similarities and differences between these two systems.Comment: 6 pages, 2 figures; accepted by Ap

Incorporating Electrical Distribution Network Structure into Energy Portfolio Optimization for an Isolated Grid

AbstractIn large scale electricity grids, the goal to reduce fossil fuel dependence can be addressed in multiple ways: generation, storage technologies, demand response, etc. In an isolated grid not connected to a transmission infrastructure, such as a military base or isolated resort, the problem is more difficult to address because of space and funding limitations, less efficient supply chains, and reliability concerns. Design for zero fossil fuel reliance in an isolated grid should combine these solutions in a portfolio while accounting for the limitations of isolation. In this paper, a methodology is formulated to optimize energy portfolios for small scale independently operated grids. Previous studies have achieved this but do not include the structure and constraints imposed by the isolated distribution grid. To address this need, the standard optimization tool, NREL's HOMER, has been linked with a grid analysis tool, PowerWorld, to take into account the design variables arising from the structure of the distribution grid, such as the need for replacement or extension of lines, extra construction space, or transformers. These added optimization factors modify HOMER's ranking of optimized portfolios as well as the economic analysis. A discussion of implications of the results to larger grid systems modeling is provided

Modeling and performance of a 100-element pHEMT grid amplifier

A 100-element hybrid grid amplifier has been fabricated, The active devices in the grid are custom-made pseudomorphic high electron mobility transistor (pHEMT) differential-pair chips. We present a model for gain analysis and compare measurements with theory. The grid includes stabilizing resistors in the gate. Measurements show the grid has a peak gain of 10 db when tuned for 10 GHz and a gain of 12 dB when tuned for 9 GHz. The maximum 3-dB bandwidth is 15% at 9 GHz. The minimum noise figure is 3 dB. The maximum saturated output power is 3.7 W, with a peak power-added efficiency of 12%. These results area significant improvement over previous grid amplifiers based on heterojunction bipolar transistors (HBT's)

Investigating the Impacts of Modeling Variables- A Case Study with Smart Grid Demand Response

AbstractWhen modeling and simulating a novel system to be designed, a modeler defines design variables, i.e., those parameters pertaining to the system to be realized, as well as modeling & simulation variables (M/SV), i.e., parameters regarding how the system (as an abstraction of reality) should be modeled and simulated. In this paper, the authors examine the influence of M/SV for a specific case of the conceptual design of a demand response (DR) program. DR is a proposed Smart Grid capability that can be implemented by a utility into an electricity distribution grid. M/SV considered include simulation time-step, number of electricity consumers, and seed variables used in modeling stochastic behavior. The influence of these variables on the ability of the DR simulation environment to produce accurate load curves and peaks is analyzed. For some M/SV, is shown that increased fidelity offers diminishing returns on greater computation time. Quantification of the influence of M/SV is used to support discussion and to identify important considerations when modeling large scale DR past the conceptual design stage

A study comparing the actions of gabapentin and pregabalin on the electrophysiological properties of cultured DRG neurones from neonatal rats

BACKGROUND: Gabapentin and pregabalin have wide-ranging therapeutic actions, and are structurally related to the inhibitory neurotransmitter GABA. Gabapentin, pregablin and GABA can all modulate voltage-activated Ca(2+ )channels. In this study we have used whole cell patch clamp recording and fura-2 Ca(2+ )imaging to characterise the actions of pregabalin on the electrophysiological properties of cultured dorsal root ganglion (DRG) neurones from neonatal rats. The aims of this study were to determine whether pregabalin and gabapentin had additive inhibitory effects on high voltage-activated Ca(2+ )channels, evaluate whether the actions of pregabalin were dependent on GABA receptors and characterise the actions of pregabalin on voltage-activated potassium currents. RESULTS: Pregabalin (25 nM – 2.5 μM) inhibited 20–30% of the high voltage-activated Ca(2+ )current in cultured DRG neurones. The residual Ca(2+ )current recorded in the presence of pregabalin was sensitive to the L-type Ca(2+ )channel modulator, Bay K8644. Saturating concentrations of gabapentin failed to have additive effects when applied with pregabalin, indicating that these two compounds act on the same type(s) of voltage-activated Ca(2+ )channels but the majority of Ca(2+ )current was resistant to both drugs. The continual application of GABA, the GABA(B )receptor antagonist CGP52432, or intracellular photorelease of GTP-γ-S had no effect on pregabalin-induced inhibition of Ca(2+ )currents. Although clear inhibition of Ca(2+ )influx was produced by pregabalin in a population of small neurones, a significant population of larger neurones showed enhanced Ca(2+ )influx in response to pregabalin. The enhanced Ca(2+ )influx evoked by pregabalin was mimicked by partial block of K(+ )conductances with tetraethylammonium. Pregabalin produced biphasic effects on voltage-activated K(+ )currents, the inhibitory effect of pregabalin was prevented with apamin. The delayed enhancement of K(+ )currents was attenuated by pertussis toxin and by intracellular application of a (Rp)-analogue of cAMP. CONCLUSIONS: Pregabalin reduces excitatory properties of cultured DRG neurones by modulating voltage-activated Ca(2+ )and K(+ )channels. The pharmacological activity of pregabalin is similar but not identical to that of gabapentin. The actions of pregabalin may involve both extracellular and intracellular drug target sites and modulation of a variety of neuronal conductances, by direct interactions, and through intracellular signalling involving protein kinase A

The Nature of SN 1961V

The nature of SN 1961V has been uncertain. Its peculiar optical light curve and slow expansion velocity are similar to those of super-outbursts of luminous blue variables (LBVs), but its nonthermal radio spectral index and declining radio luminosity are consistent with decades-old supernovae (SNe). We have obtained Hubble Space Telescope STIS images and spectra of the stars in the vicinity of SN 1961V, and find Object 7 identified by Filippenko et al. to be the closest to the optical and radio positions of SN 1961V. Object 7 is the only point source detected in our STIS spectra and only its H-alpha emission is detected; it cannot be the SN or its remnant because of the absence of forbidden lines. While the H-alpha line profile of Object 7 is remarkably similar to that of eta Car, the blue color (similar to an A2Ib supergiant) and lack of appreciable variability are unlike known post-outburst LBVs. We have also obtained Very Long Baseline Array (VLBA) observations of SN 1961V at 18 cm. The non-detection of SN 1961V places a lower limit on the size of the radio-emitting region, 7.6 mas or 0.34 pc, which implies an average expansion velocity in excess of 4,400 km/s, much higher than the optical expansion velocity measured in 1961. We conclude the following: (1) A SN occurred in the vicinity of SN 1961V a few decades ago. (2) If the SN 1961V light maximum originates from a giant eruption of a massive star, Object 7 is the most probable candidate for the survivor, but its blue color and lack of significant variability are different from a post-outburst eta Car. (3) The radio SN and Object 7 could be physically associated with each other through a binary system. (4) Object 7 needs to be monitored to determine its nature and relationship to SN 1961V.Comment: 16 pages, 3 figures, accepted by the Astronomical Journal for the 2004 May issu

Diagnostic Imaging in the Medical Support of the Future Missions to the Moon

This viewgraph presentation is a course that reviews the diagnostic imaging techniques available for medical support on the future moon missions. The educational objectives of the course are to: 1) Update the audience on the curreultrasound imaging in space flight; 2) Discuss the unique aspects of conducting ultrasound imaging on ISS, interplanetary transit, ultrasound imaging on ISS, interplanetary transit, and lunar surface operations; and 3) Review preliminary data obtained in simulations of medical imaging in lunar surface operations