5,596 research outputs found
Largest Mesh Deployable Antenna Technology
Preliminary assessments by both government and industry indicate that applications exist in the areas of communications, radio astronomy, and Earth observations requiring large, space based antennas. The mesh deployable antenna, based on its demonstrated success in the smaller aperture range, provides a promising near term capability for satisfying a significant number of these space-based applications. In this article the technology status of mesh deployable antennas is reviewed and design concepts applicable to very large mesh deployable reflectors are discussed. The present state-of-the-art performance is presented along with projections of potential performance improvement. These are compared with identified focus missions from the NASA Large Space Structures Technology (LSST) Program
Commentary: The Feasibility of a Human Milk Bank in Kerala State, India.
yesDonated Human Milk Banking is a trending topic in healthcare management and has potential for business development opportunities at hospitals and independent organisations in developing countries. A preliminary definition of a Human Milk Bank “is a service established to recruit breast milk donors, collect donated milk, and then process, screen, store, and distribute the milk to meet infants’ specific needs for optimal health. Although there are indications about the beginning of such practices date back to the 2001’s, private sector human milk banking has gained momentum in terms of popularity and acceptability. There is evidence of the presence of human milk banks in the USA during the 1990’s, which potential was affected by the development of specialty formulas, safety issues linked with viral transmission, and lack of credible clinical research in this area. However, recent developments in clinical studies, government cooperation with medical research centres and health authorities have shown considerable improvement in the public view of Human Milk Bank’s creating a positive climate for private sector provision
The Impact of New EUV Diagnostics on CME-Related Kinematics
We present the application of novel diagnostics to the spectroscopic
observation of a Coronal Mass Ejection (CME) on disk by the Extreme Ultraviolet
Imaging Spectrometer (EIS) on the Hinode spacecraft. We apply a recently
developed line profile asymmetry analysis to the spectroscopic observation of
NOAA AR 10930 on 14-15 December 2006 to three raster observations before and
during the eruption of a 1000km/s CME. We see the impact that the observer's
line-of-sight and magnetic field geometry have on the diagnostics used.
Further, and more importantly, we identify the on-disk signature of a
high-speed outflow behind the CME in the dimming region arising as a result of
the eruption. Supported by recent coronal observations of the STEREO
spacecraft, we speculate about the momentum flux resulting from this outflow as
a secondary momentum source to the CME. The results presented highlight the
importance of spectroscopic measurements in relation to CME kinematics, and the
need for full-disk synoptic spectroscopic observations of the coronal and
chromospheric plasmas to capture the signature of such explosive energy release
as a way of providing better constraints of CME propagation times to L1, or any
other point of interest in the heliosphere.Comment: Accepted to appear in Solar Physics Topical Issue titled "Remote
Sensing of the Inner Heliosphere". Manuscript has 14 pages, 5 color figures.
Movies supporting the figures can be found in
http://download.hao.ucar.edu/pub/mscott/papers/Weathe
Twisting type-N vacuum fields with a group
We derive the equations corresponding to twisting type-N vacuum gravitational
fields with one Killing vector and one homothetic Killing vector by using the
same approach as that developed by one of us in order to treat the case with
two non-commuting Killing vectors. We study the case when the homothetic
parameter takes the value -1, which is shown to admit a reduction to a
third-order real ordinary differential equation for this problem, similar to
that previously obtained by one of us when two Killing vectors are present.Comment: LaTeX, 11 pages. To be published in Classical and Quantum Gravit
Chickadee songs provide hidden clues to singers’ locations
Funding: LMG was supported by an Izaak Walton Killam Memorial Scholarship (IWKMS) at UofA and is currently a BBSRC Anniversary Future Leader Fellow.Coordination of actions requires that organisms actively monitor the movements of others. The current study examined acoustic cues within the fee-bee song of chickadees that may provide listening conspecifics with information about the movements of singers. The difference between direct and reverberant acoustic energy present during the second note of the fee-bee song provided clear indications of how far the song had traveled. Preliminary analyses suggest that this distance cue may be robust to variations in the spectra and amplitude of song components,and that the acoustic features of the fee-bee song may facilitate simultaneous comparisons of reverberating fees with directly received bees by listening birds. Comparing coincident reverberation with directly received sounds may be a previously unsuspected way that animals living in reverberant environments can monitor the movements and interactions of conspecifics.Publisher PDFPeer reviewe
Molecular regulation of GLUT-4 targeting in 3T3-L1 adipocytes
Insulin stimulates glucose transport in muscle and adipose tissue by triggering the movement of the glucose transporter GLUT-4 from an intracellular compartment to the cell surface. Fundamental to this process is the intracellular sequestration of GLUT-4 in nonstimulated cells. Two distinct targeting motifs in the amino and carboxy termini of GLUT-4 have been previously identified by expressing chimeras comprised of portions of GLUT-4 and GLUT-1, a transporter isoform that is constitutively targeted to the cell surface, in heterologous cells. These motifs-FQQ1 in the NH terminus and LL in the COOH terminus-resemble endocytic signals that have been described in other proteins. In the present study we have investigated the roles of these motifs in GLUT-4 targeting in insulin-sensitive cells. Epitope-tagged GLUT-4 constructs engineered to differentiate between endogenous and transfected GLUT-4 were stably expressed in 3T3-L1 adipocytes. Targeting was assessed in cells incubated in the presence or absence of insulin by subcellular fractionation. The targeting of epitope-tagged GLUT-4 was indistinguishable from endogenous GLUT-4. Mutation of the FQQI motif (F to A) caused GLUT-4 to constitutively accumulate at the cell surface regardless of expression level. Mutation of the dileucine motif (LL to AA) caused an increase in cell surface distribution only at higher levels of expression, but the overall cell surface distribution of this mutant was less than that of the amino-terminal mutants. Both NH- and COOH-terminal mutants retained insulin-dependent movement from an intracellular to a cell surface locale, suggesting that neither of these motifs is involved in the insulin-dependent redistribution of GLUT-4. We conclude that the phenylalanine-based NH-terminal and the dileucine-based COOH-terminal motifs play important and distinct roles in GLUT-4 targeting in 3T3-L1 adipocytes
The Whole Heliosphere Interval in the Context of a Long and Structured Solar Minimum: An Overview from Sun to Earth
Throughout months of extremely low solar activity during the recent extended solar-cycle minimum, structural evolution continued to be observed from the Sun through the solar wind and to the Earth. In 2008, the presence of long-lived and large low-latitude coronal holes meant that geospace was periodically impacted by high-speed streams, even though solar irradiance, activity, and interplanetary magnetic fields had reached levels as low as, or lower than, observed in past minima. This time period, which includes the first Whole Heliosphere Interval (WHI 1: Carrington Rotation (CR) 2068), illustrates the effects of fast solar-wind streams on the Earth in an otherwise quiet heliosphere. By the end of 2008, sunspots and solar irradiance had reached their lowest levels for this minimum (e.g., WHI 2: CR 2078), and continued solar magnetic-flux evolution had led to a flattening of the heliospheric current sheet and the decay of the low-latitude coronal holes and associated Earth-intersecting high-speed solar-wind streams. As the new solar cycle slowly began, solar-wind and geospace observables stayed low or continued to decline, reaching very low levels by June – July 2009. At this point (e.g., WHI 3: CR 2085) the Sun–Earth system, taken as a whole, was at its quietest. In this article we present an overview of observations that span the period 2008 – 2009, with highlighted discussion of CRs 2068, 2078, and 2085. We show side-by-side observables from the Sun’s interior through its surface and atmosphere, through the solar wind and heliosphere and to the Earth’s space environment and upper atmosphere, and reference detailed studies of these various regimes within this topical issue and elsewhere
The inhibitor of Pm8 in certain 1BL.1RS wheat genotypes
INTRODUCTION: Nevirapine (NVP) induces cytochrome P450 3A4 by which rilpivirine (RPV) is metabolized. Switching NVP to RPV could result in decreased RPV exposure with subsequent virological failure and dyslipidemia because NVP is regarded as the least dyslipidemic, non-nucleoside, reverse transcriptase inhibitor. This trial evaluated the efficacy, pharmacokinetics, safety and cardiovascular risks of switching NVP to RPV. MATERIALS AND METHODS: Prospective open label controlled trial. HIV-1 patients with HIV-1 RNA <50 copies/mL on once daily NVP, emtricitabine/tenofovir (FTC/TDF) switched to single tablet RPV/FTC/TDF. Eligible patients on NVP, FTC/TDF were controls. Primary endpoint was week 12 HIV-1 RNA <50 copies/mL by intention to treat analysis. Secondary endpoints were week 24 HIV-1 RNA <50 copies/mL, NVP and RPV pharmacokinetics, safety and fasting lipids, Framingham risk scores (FRS) and Adult Treatment Panel III (ATP-III) lipid goals. RESULTS: Of 189 eligible patients, we included 50 RPV switchers and 139 NVP controls. Week 12 HIV-RNA was <50 copies/mL in 46/50 switchers (92.0%) which was not different from the hypothesized 90% week 12 suppression rate (p=.431). Forty-four of 50 switchers had week 24 HIV-1 RNA <50 copies/mL compared to 126/139 controls (difference: 2.6%, 95% CI -7.6% to 12.8%, p=.593). NVP plasma concentrations were below detection level in all at week 3. Mean week 1 RPV trough concentration was 0.083 mg/L and comparable to phase III trial data (p=0.747). Adverse events occurred in 36 switchers, the majority (82.0%) were grade one. Two switchers discontinued RPV for side effects. Significant changes over 24 weeks (p<0.001) were observed in switchers on total cholesterol (TC, -0.67 mmol/L, 95% CI -0.50 to 0.83), low density lipoprotein (LDL)-C (-0.36, 95% CI -0.21 to -0.51) and high density lipoprotein (HDL)-C (-0.28, 95% CI -0.20 to -0.35). The TC/HDL-C ratio increased 0.20 (95% CI 0.02 to 0.37; p=.029) and systolic blood pressure decreased 6.0 mmHg (95% CI -1.7 to -10.3; p=.007). The median FRS did not change over 24 weeks (8.4% vs. 7.7%; p=.119). More patients achieved LDL-C (+15%; p=.016) and TC (+25%; p<0.001) ATP-III treatment goals at week 24 on RPV. CONCLUSIONS: A NVP to RPV switch does not influence RPV exposure and results in adequate ongoing HIV-1 suppression. RPV could be an option for patients at risk for cardiovascular diseases
- …