29,010 research outputs found
Continued development of doped-germanium photoconductors for astronomical observations at wavelengths from 30 to 120 micrometers
The development of doped-germanium detectors which have optimized performance in the 30- to 120-mu m wavelength range and are capable of achieving the objectives of the infrared astronomical satellite (IRAS) space mission is discussed. Topics covered include the growth and evaluation of Ge:Ga and Ge:Be crystals, procedures for the fabrication and testing of detectors, irradiance calculations, detector responsivity, and resistance measurements through MOSFET. Test data are presented in graphs and charts
A 3-3-1 model with right-handed neutrinos based on the family symmetry
We present the first multiscalar singlet extension of the 3-3-1 model with
right-handed neutrinos, based on the family
symmetry, supplemented by the flavor group,
consistent with current low energy fermion flavor data. In the model under
consideration, the light active neutrino masses are generated from a double
seesaw mechanism and the observed pattern of charged fermion masses and quark
mixing angles is caused by the breaking of the discrete group at very high energy. Our model
has only 14 effective free parameters, which are fitted to reproduce the
experimental values of the 18 physical observables in the quark and lepton
sectors. The obtained physical observables for the quark sector agree with
their experimental values, whereas those ones for the lepton sector also do,
only for the inverted neutrino mass hierarchy. The normal neutrino mass
hierarchy scenario of the model is disfavored by the neutrino oscillation
experimental data. We find an effective Majorana neutrino mass parameter of
neutrinoless double beta decay of 22 meV, a leptonic Dirac
CP violating phase of and a Jarlskog invariant of about
for the inverted neutrino mass spectrum.Comment: 22 pages. Final version published in European Physical Journal C.
arXiv admin note: text overlap with arXiv:1601.03300, arXiv:1309.656
A variant of 3-3-1 model for the generation of the SM fermion mass and mixing pattern
We propose an extension of the 3-3-1 model with an additional symmetry group
and an extended scalar sector. To our
best knowledge this is the first example of a renormalizable 3-3-1 model, which
allows explanation of the SM fermion mass hierarchy by a sequential loop
suppression: tree-level top and exotic fermion masses, 1-loop bottom, charm,
tau and muon masses; 2-loop masses for the light up, down, strange quarks as
well as for the electron. The light active neutrino masses are generated from a
combination of linear and inverse seesaw mechanisms at two loop level. The
model also has viable fermionic and scalar dark matter candidates.Comment: 35 pages, 4 figures. Version accepted for publication in JHE
Solo women - a new agenda for ageing?
A short review of research findings from an online survey of women living without partners and children as they enter later life
Towards the development of the psychosocial impact of assistive devices scale for continence (C-PIADS)
BACKGROUND: Current outcome measures for continence management devices do not adequately address psychosocial impact. The PIADS is an assessment tool that has been shown to reliably predict the adoption and use of assistive technology devices, but it is not widely used for continence devices. OBJECTIVE: To explore whether the PIADS requires modification to address the particular needs of continence device users and to inform any subsequent item development. METHODS: The study used interpretive methods in which qualitative information from semi-structured interviews was combined with the findings from cognitive interviews for questionnaire pre-testing. A total of 40 participants in UK and Canada were interviewed. RESULTS: Few participants had difficulty in understanding or relating to the majority of PIADS items. Several items were not considered relevant to continence and some areas for potential new items were uncovered. Embarrassment and concealment of urinary incontinence from others were common topics. CONCLUSIONS: The PIADS appears to fundamentally address many, but not all, of the important psychosocial concerns of adults who have continence difficulties. A version for continence, the C-PIADS, will require modification of the PIADS and is likely to contain some new items
CXCR4-targeted and MMP-responsive iron oxide nanoparticles for enhanced magnetic resonance imaging
MRI offers high spatial resolution with excellent tissue penetration but it has limited sensitivity and the commonly administered contrast agents lack specificity. In this study, two sets of iron oxide nanoparticles (IONPs) were synthesized that were designed to selectively undergo copper-free click conjugation upon sensing of matrix metalloproteinase (MMP) enzymes, thereby leading to a self-assembled superparamagnetic nanocluster network with T2 signal enhancement properties. For this purpose, IONPs with bioorthogonal azide and alkyne surfaces masked by polyethylene glycol (PEG) layers tethered to CXCR4-targeted peptide ligands were synthesized and characterized. The IONPs were tested in vitro and T2 signal enhancements of around 160 % were measured when the IONPs were incubated with cells expressing MMP2/9 and CXCR4. Simultaneous systemic administration of the bioorthogonal IONPs in tumor-bearing mice demonstrated the signal-enhancing ability of these ‘smart’ self-assembling nanomaterials
Calcium and magnesium absorption and retention by growing goats offered diets with different calcium sources
Calcium addition is necessary in order to balance the high phosphorus concentrations that are characteristic of high-concentrate ruminant diets. However, calcium sources differ in their bioavailability. Our objective was to determine apparent calcium and magnesium absorption and retention in goats offered diets containing different sources of calcium. Spanish-Boer goats (n = 18; 19.6 ± 1.88 kg) were stratified by body weight (BW) and sex and randomized to dietary treatments consisting of Purina Antlermax 16 containing either calcium carbonate (CC), Calmin (CM) or Milk Cal (MC). Goats were adapted to a control, corn-based high-concentrate diet on pasture and then moved to individual 1.0 × 1.5-m pens with plastic coated expanded metal floors, and adjusted to their respective diets along with removal of hay from the diet over a 7-d period. Goats were then offered their respective diets at a total of 2% of BW in equal feedings at 8:30 AM and 5:00 PM for an additional 14-d adaption period to diet and facilities followed by a 7-d collection of total urine and feces. Data were analyzed using PROC MIXED of SAS. Calcium and magnesium intake were not different (P ≥ 0.12) among diets. Calcium and magnesium apparent absorption and retention (g/d and % of intake) were greatest (P \u3c 0.05) in goats offered CC and did not differ (P ≥ 0.20) between goats offered the CM and MC diets. Therefore, calcium and magnesium were more available for goats from the diet containing calcium carbonate compared with diets containing Calmin and Milk Cal
The interpretation of the field angle dependence of the critical current in defect-engineered superconductors
We apply the vortex path model of critical currents to a comprehensive
analysis of contemporary data on defect-engineered superconductors, showing
that it provides a consistent and detailed interpretation of the experimental
data for a diverse range of materials. We address the question of whether
electron mass anisotropy plays a role of any consequence in determining the
form of this data and conclude that it does not. By abandoning this false
interpretation of the data, we are able to make significant progress in
understanding the real origin of the observed behavior. In particular, we are
able to explain a number of common features in the data including shoulders at
intermediate angles, a uniform response over a wide angular range and the
greater discrimination between individual defect populations at higher fields.
We also correct several misconceptions including the idea that a peak in the
angular dependence of the critical current is a necessary signature of strong
correlated pinning, and conversely that the existence of such a peak implies
the existence of correlated pinning aligned to the particular direction. The
consistency of the vortex path model with the principle of maximum entropy is
introduced.Comment: 14 pages, 7 figure
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