4,935 research outputs found
Metastable Flux Configurations and de Sitter Spaces
We derive stability conditions for the critical points of the no-scale scalar
potential governing the dynamics of the complex structure moduli and the
axio-dilaton in compactifications of type IIB string theory on Calabi-Yau
three-folds. We discuss a concrete example of a T^6 orientifold. We then
consider the four-dimensional theory obtained from compactifications of type
IIB string theory on non-geometric backgrounds which are mirror to rigid
Calabi-Yau manifolds and show that the complex structure moduli fields can be
stabilized in terms of H_{RR} only, i.e. with no need of orientifold
projection. The stabilization of all the fields at weak coupling, including the
axio-dilaton, may require to break supersymmetry in the presence of H_{NS} flux
or corrections to the scalar potential.Comment: 24 page
Photothermoelastic response of zincblende crystals to radiation from a THz-frequency quantum cascade laser
We investigate the photothermoelastic response of ZnTe and GaP crystals irradiated by THz-frequency radiation from a quantum cascade laser. We present a full theoretical description of this interaction that agrees well with the measured response
Non-invasive assessment of peripheral arterial disease: Automated ankle brachial index measurement and pulse volume analysis compared to duplex scan
Objectives: This cross-sectional study aimed to individually and cumulatively compare sensitivity and specificity of the (1) ankle brachial index and (2) pulse volume waveform analysis recorded by the same automated device, with the presence or absence of peripheral arterial disease being verified by ultrasound duplex scan.
Methods: Patients (n=205) referred for lower limb arterial assessment underwent ankle brachial index measurement and pulse volume waveform recording using volume plethysmography, followed by ultrasound duplex scan. The presence of peripheral arterial disease was recorded if ankle brachial index 50% was evident with ultrasound duplex scan. Outcome measure was agreement between the measured ankle brachial index and interpretation of pulse volume waveform for peripheral arterial disease diagnosis, using ultrasound duplex scan as the reference standard.
Results: Sensitivity of ankle brachial index was 79%, specificity 91% and overall accuracy 88%. Pulse volume waveform sensitivity was 97%, specificity 81% and overall accuracy 85%. The combined sensitivity of ankle brachial index and pulse volume waveform was 100%, specificity 76% and overall accuracy 85%.
Conclusion: Combining these two diagnostic modalities within one device provided a highly accurate method of ruling out peripheral arterial disease, which could be utilised in primary care to safely reduce unnecessary secondary care referrals
Two-loop RGEs with Dirac gaugino masses
The set of renormalisation group equations to two loop order for general
supersymmetric theories broken by soft and supersoft operators is completed. As
an example, the explicit expressions for the RGEs in a Dirac gaugino extension
of the (N)MSSM are presented.Comment: 10 pages + 24 pages of RGEs in appendix; no figure
Galaxy and Mass Assembly (GAMA): the effect of close interactions on star formation in galaxies
The modification of star formation (SF) in galaxy interactions is a complex process, with SF observed to be both enhanced in major mergers and suppressed in minor pair interactions. Such changes likely to arise on short time-scales and be directly related to the galaxy–galaxy interaction time. Here we investigate the link between dynamical phase and direct measures of SF on different time-scales for pair galaxies, targeting numerous star- formation rate (SFR) indicators and comparing to pair separation, individual galaxy mass and pair mass ratio. We split our sample into the higher (primary) and lower (secondary) mass galaxies in each pair and find that SF is indeed enhanced in all primary galaxies but suppressed in secondaries of minor mergers. We find that changes in SF of primaries are consistent in both major and minor mergers, suggesting that SF in the more massive galaxy is agnostic to pair mass ratio. We also find that SF is enhanced/suppressed more strongly for short-duration SFR indicators (e.g. Hα), highlighting recent changes to SF in these galaxies, which are likely to be induced by the interaction. We propose a scenario where the lower mass galaxy has its SF suppressed by gas heating or stripping, while the higher mass galaxy has its SF enhanced, potentially by tidal gas turbulence and shocks. This is consistent with the seemingly contradictory observations for both SF suppression and enhancement in close pairs
A 19-SNP coronary heart disease gene score profile in subjects with type 2 diabetes: the coronary heart disease risk in type 2 diabetes (CoRDia study) study baseline characteristics
Background: The coronary risk in diabetes (CoRDia) trial (n = 211) compares the effectiveness of usual diabetes care with a self-management intervention (SMI), with and without personalised risk information (including genetics), on clinical and behavioural outcomes. Here we present an assessment of randomisation, the cardiac risk genotyping assay, and the genetic characteristics of the recruits. / Methods: Ten-year coronary heart disease (CHD) risk was calculated using the UKPDS score. Genetic CHD risk was determined by genotyping 19 single nucleotide polymorphisms (SNPs) using Randox’s Cardiac Risk Prediction Array and calculating a gene score (GS). Accuracy of the array was assessed by genotyping a subset of pre-genotyped samples (n = 185). / Results: Overall, 10-year CHD risk ranged from 2–72 % but did not differ between the randomisation groups (p = 0.13). The array results were 99.8 % concordant with the pre-determined genotypes. The GS did not differ between the Caucasian participants in the CoRDia SMI plus risk group (n = 66) (p = 0.80) and a sample of UK healthy men (n = 1360). The GS was also associated with LDL-cholesterol (p = 0.05) and family history (p = 0.03) in a sample of UK healthy men (n = 1360). / Conclusions: CHD risk is high in this group of T2D subjects. The risk array is an accurate genotyping assay, and is suitable for estimating an individual’s genetic CHD risk. / Trial registration: This study has been registered at ClinicalTrials.gov; registration identifier NCT0189178
Three-well, resonant-phonon depopulation, quantum cascade lasers with thinned active regions and surface-plasmon waveguides
We report, for the first time, high performance three-well, resonant-phonon depopulation, terahertz quantum cascade lasers with thinned active regions. Lasers operated at 3.1 THz in a surface plasmon waveguide. The variation of output power, maximum operating temperature, and threshold current density is presented for active regions of 10 µm, 7,5 µm, 6 µm, and 5 µm thickness, and in each case results are presented as a function of duty cycle
The Wide Area VISTA Extra-galactic Survey (WAVES)
The "Wide Area VISTA Extra-galactic Survey" (WAVES) is a 4MOST Consortium Design Reference Survey which will use the VISTA/4MOST facility to spectroscopically survey ~2million galaxies to mag. WAVES consists of two interlocking galaxy surveys ("WAVES-Deep" and "WAVES-Wide"), providing the next two steps beyond the highly successful 1M galaxy Sloan Digital Sky Survey and the 250k Galaxy And Mass Assembly survey. WAVES will enable an unprecedented study of the distribution and evolution of mass, energy, and structures extending from 1-kpc dwarf galaxies in the local void to the morphologies of 200-Mpc filaments at . A key aim of both surveys will be to compare comprehensive empirical observations of the spatial properties of galaxies, groups, and filaments, against state-of-the-art numerical simulations to distinguish between various Dark Matter models
Preterm birth a long distance from home and its significant social and financial stress
The present paper reports a retrospective cohort of preterm infants admitted to our hospital who delivered outside the normal geographical catchment area of the mother's local level three neonatal nursery. Nineteen mothers had 21 preterm infants (23.1-34.9 weeks, 500-2330 g born) where 14 infants required ventilation (median 57 h, range 3-428). Eighteen survivors had a median length of stay of 41 days (range 3-91). Twelve of 19 mothers were interviewed: all described isolation, loneliness, poor social support and significant financial hardship related to getting their infants back to a local hospital or home. To avoid these problems, we recommend confining travel to within a short distance from home or local maternity unit after 22 weeks
Galaxy and Mass Assembly (GAMA): Panchromatic data release (far-UV–far-IR) and the low-z energy budget
We present the Galaxy And Mass Assembly (GAMA) Panchromatic Data Release (PDR) constituting over 230 deg2 of imaging with photometry in 21 bands extending from the farUV to the far-IR. These data complement our spectroscopic campaign of over 300k galaxies, and are compiled from observations with a variety of facilities including: GALaxy Evolution eXplorer, Sloan Digital Sky Survey, Visible and Infrared Telescope for Astronomy (VISTA), Wide-field Infrared Survey Explorer, and Herschel, with the GAMA regions currently being surveyedbyVLTSurveyTelescope(VST)andscheduledforobservationsbyAustralianSquare Kilometer Array Pathfinder (ASKAP). These data are processed to a common astrometric solution, from which photometry is derived for ∼221373 galaxies with r < 19.8 mag. Online tools are provided to access and download data cutouts, or the full mosaics of the GAMA regions in each band. We focus, in particular, on the reduction and analysis of the VISTA VIsta Kilo-degree INfrared Galaxy data, and compare to earlier data sets (i.e. 2MASS and UKIDSS) before combining the data and examining its integrity. Having derived the 21-band photometric catalogue, we proceed to fit the data using the energy balance code MAGPHYS. These measurements are then used to obtain the first fully empirical measurement of the
0.1–500 μm energy output of the Universe. Exploring the cosmic spectral energy distribution
across three time-intervals (0.3–1.1, 1.1–1.8, and 1.8–2.4 Gyr), we find that the Universe is currently generating (1.5 ± 0.3) × 1035 h70 W Mpc−3, down from (2.5 ± 0.2) × 1035 h70 W Mpc−3 2.3 Gyr ago. More importantly, we identify significant and smooth evolution in the integrated photon escape fraction at all wavelengths, with the UV escape fraction increasing from 27(18) per cent at z= 0.18 in NUV(FUV) to 34(23) per cent at z= 0.06. The GAMA PDR can be found at: http://gama-psi.icrar.org/
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