7,014 research outputs found
Near room-temperature colossal magnetodielectricity and multiglass properties in partially-disordered La2NiMnO6
We report magnetic, dielectric and magnetodielectric responses of pure
monoclinic bulk phase of partially-disordered La2NiMnO6, exhibiting a spectrum
of unusual properties and establish that this system intrinsically is a true
multiglass with a large magnetodielectric coupling (8-20%) over a wide range of
temperatures (150 - 300 K). Specifically, our results establish a unique way to
obtain colossal magnetodielectricity, independent of any striction effects, by
engineering the asymmetric hopping contribution to the dielectric constant via
the tuning of the relative spin orientations between neighboring magnetic ions
in a transition metal oxide system. We discuss the role of anti-site (Ni-Mn)
disorder in emergence of these unusual properties.Comment: 5 pages, 4 figures, Slightly revised version of previous article in
condmat: arXiv:1202.4319v
Cygnus X-3 transition from the ultrasoft to the hard state
Aims: The nature of Cygnus X-3 is still not understood well. This binary
system might host a black hole or a neutron star. Recent observations by
INTEGRAL have shown that Cygnus X-3 was again in an extremely ultrasoft state.
Here we present our analysis of the transition from the ultrasoft state,
dominated by blackbody radiation at soft X-rays plus non-thermal emission in
the hard X-rays, to the low hard state.
Methods: INTEGRAL observed Cyg X-3 six times during three weeks in late May
and early June 2007. Data from IBIS/ISGRI and JEM-X1 were analysed to show the
spectral transition.
Results: During the ultrasoft state, the soft X-ray spectrum is
well-described by an absorbed (NH = 1.5E22 1/cm**2) black body model, whereas
the X-ray spectrum above 20 keV appears to be extremely low and hard (Gamma =
1.7). During the transition, the radio flux rises to a level of >1 Jy, and the
soft X-ray emission drops by a factor of 3, while the hard X-ray emission rises
by a factor of 14 and becomes steeper (up to Gamma = 4).
Conclusions: The ultrasoft state apparently precedes the emission of a jet,
which is apparent in the radio and hard X-ray domain.Comment: 4 pages, 3 figures, accepted for publication as A&A Research Not
Modeling and Simulation of a TFET-Based Label-Free Biosensor with Enhanced Sensitivity
This study discusses the use of a triple material gate (TMG) junctionless tunnel field-effect transistor (JLTFET) as a biosensor to identify different protein molecules. Among the plethora of existing types of biosensors, FET/TFET-based devices are fully compatible with conventional integrated circuits. JLTFETs are preferred over TFETs and JLFETs because of their ease of fabrication and superior biosensing performance. Biomolecules are trapped by cavities etched across the gates. An analytical mathematical model of a TMG asymmetrical hetero-dielectric JLTFET biosensor is derived here for the first time. The TCAD simulator is used to examine the performance of a dielectrically modulated label-free biosensor. The voltage and current sensitivity of the device and the effects of the cavity size, bioanalyte electric charge, fill factor, and location on the performance of the biosensor are also investigated. The relative current sensitivity of the biosensor is found to be about 1013. Besides showing an enhanced sensitivity compared with other FET- and TFET-based biosensors, the device proves itself convenient for low-power applications, thus opening up numerous directions for future research and applications
Childhood conditions influence adult progesterone levels
Background Average profiles of salivary progesterone in women vary significantly at the inter- and intrapopulation level as a function of age and acute energetic conditions related to energy intake, energy expenditure, or a combination of both. In addition to acute stressors, baseline progesterone levels differ among populations. The causes of such chronic differences are not well understood, but it has been hypothesised that they may result from varying tempos of growth and maturation and, by implication, from diverse environmental conditions encountered during childhood and adolescence. Methods and Findings To test this hypothesis, we conducted a migrant study among first- and second-generation Bangladeshi women aged 19–39 who migrated to London, UK at different points in the life-course, women still resident in Bangladesh, and women of European descent living in neighbourhoods similar to those of the migrants in London (total n = 227). Data collected included saliva samples for radioimmunoassay of progesterone, anthropometrics, and information from questionnaires on diet, lifestyle, and health. Results from multiple linear regression, controlled for anthropometric and reproductive variables, show that women who spend their childhood in conditions of low energy expenditure, stable energy intake, good sanitation, low immune challenges, and good health care in the UK have up to 103% higher levels of salivary progesterone and an earlier maturation than women who develop in less optimal conditions in Sylhet, Bangladesh (F9,178 = 5.05, p < 0.001, standard error of the mean = 0.32; adjusted R2 = 0.16). Our results point to the period prior to puberty as a sensitive phase when changes in environmental conditions positively impact developmental tempos such as menarcheal age (F2,81 = 3.21, p = 0.03) and patterns of ovarian function as measured using salivary progesterone (F2,81 = 3.14, p = 0.04). Conclusions This research demonstrates that human females use an extended period of the life cycle prior to reproductive maturation to monitor their environment and to modulate reproductive steroid levels in accordance with projected conditions they might encounter as adults. Given the prolonged investment of human pregnancy and lactation, such plasticity (extending beyond any intrauterine programming) enables a more flexible and finely tuned adjustment to the potential constraints or opportunities of the later adult environment. This research is the first, to our knowledge, to demonstrate a postuterine developmental component to variation in reproductive steroid levels in women
pi-Conjugation and conformation in a semiconducting polymer: small angle x-ray scattering study
Small angle X-ray scattering (SAXS) in
poly[2-methoxy-5-(2-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) solution
has shown the important role of pi-electron conjugation in controlling the
chain conformation and assembly. By increasing the extent of conjugation from
30 to 100 %, the persistence length (l_p) increases from 20 to 66 Angstrom.
Moreover, a pronounced second peak in the pair distribution function has been
observed in fully conjugated chain, at larger length scales. This feature
indicates that the chain segments tend to self-assemble as the conjugation
along the chain increases. Xylene enhances the rigidity of PPV backbone to
yield extended structures, while tetrahydrofuran solvates the side groups to
form compact coils in which the l_p is much shorter.Comment: accepted (J. Phy. Cond. Mat.
Carbon stars in the X-shooter Spectral Library
We provide a new collection of spectra of 35 carbon stars obtained with the
ESO/VLT X-shooter instrument as part of the X-shooter Spectral Library project.
The spectra extend from 0.3m to 2.4m with a resolving power above
8000. The sample contains stars with a broad range of (J-K) color and
pulsation properties located in the Milky Way and the Magellanic Clouds. We
show that the distribution of spectral properties of carbon stars at a given
(J-K) color becomes bimodal (in our sample) when (J-K) is larger than about
1.5. We describe the two families of spectra that emerge, characterized by the
presence or absence of the absorption feature at 1.53m, generally
associated with HCN and CH. This feature appears essentially only in
large-amplitude variables, though not in all observations. Associated spectral
signatures that we interpret as the result of veiling by circumstellar matter,
indicate that the 1.53m feature might point to episodes of dust production
in carbon-rich Miras.Comment: 29 pages, 21 figures, 9 tables, Accepted for publication in A&
Large Non-perturbative Effects of Small \Delta m^2_{21}/\Delta m^2_{31} and \sin \theta_{13} on Neutrino Oscillation and CP Violation in Matter
In the framework of three generations, we consider the CP violation in
neutrino oscillation with matter effects. At first, we show that the
non-perturbative effects of two small parameters, \Delta m_{21}^2/\Delta
m_{31}^2 and \sin \theta_{13}, become more than 50% in certain ranges of energy
and baseline length. This means that the non-perturbative effects should be
considered in detailed analysis in the long baseline experiments. Next, we
propose a method to include these effects in approximate formulas for
oscillation probabilities. Assuming the two natural conditions,
\theta_{23}=45^\circ and the fact that the matter density is symmetric, a set
of approximate formulas, which involve the non-perturbative effects, has been
derived in all channels.Comment: 25 pages, 4 figures, version to appear in JHE
Lepton polarization asymmetry in radiative dileptonic B-meson decays in MSSM
In this paper we study the polarization asymmetries of the final state lepton
in the radiative dileptonic decay of B meson (\bsllg) in the framework of
Minimal Supersymmetric Standard Model (MSSM) and various other unified models
within the framework of MSSM e.g. mSUGRA, SUGRA (where condition of
universality of scalar masses is relaxed) etc. Lepton polarization, in addition
of having a longitudinal component (\pl), can have two other components, \pt
and \pn, lying in and perpendicular to the decay plane, which are proportional
to \ml and hence are significant for final state being or
. We analyse the dependence of these polarization asymmetries
on the parameters of the various models.Comment: typos corrected to match with published versio
The use of mono- and combination drug therapy in men and women with lower urinary tract symptoms (LUTS) in the UK: a retrospective observational study
Background: Combination drug therapy for lower urinary tract symptoms (LUTS) is beneficial to selected patients and recommended by guidelines. Patterns of real-world LUTS drug use, especially combination drug therapy, have not been studied extensively. Moreover, further understanding of the recent landscape is required following the introduction of the beta-3-adrenoceptor agonist mirabegron in the UK in 2013 for overactive bladder (OAB). The objective was to describe mono- and combination drug therapy use for LUTS in patients in UK clinical practice. Methods: This was a retrospective, descriptive, observational database study using UK Clinical Practice Research Datalink GOLD and linked databases. Men and women ≥ 18 years with a first prescription for any LUTS drug from 2014 to 2016 with ≥ 12 months continuous enrollment pre- and post-index date were included. Primary endpoints were mono- or combination drug therapy use for LUTS in male and female cohorts. Secondary endpoints were description of treatment prescribed, treatment persistence and patient demographics. Data were analyzed descriptively. Sub-cohorts were defined by drugs prescribed at index date. Results: 79,472 patients (61.3% male) were included, based on index treatments. Of all men, 82.5% received any benign prostatic obstruction (BPO) drug, 25.4% any OAB drug, and 7.9% any BPO drug plus any OAB drug. As either mono- or combination drug therapy, 77.1% received an alpha-blocker, 18.9% a 5-alpha reductase inhibitor, 23.9% an antimuscarinic agent, and 2.1% mirabegron. Of all women, 94.5% received any OAB drug, 6.0% duloxetine, and 0.5% any OAB drug plus duloxetine. As either mono- or combination drug therapy, 87.7% received an antimuscarinic, and 9.7% mirabegron. In men or women receiving OAB treatment, approximately 2.5% received combination drug therapy with an antimuscarinic agent and mirabegron. For OAB drug monotherapies, mirabegron had the highest persistence in both male and female cohorts. Conclusions: This study provides a better understanding of the recent landscape of LUTS drug use in UK clinical practice. It highlights potential undertreatment of storage symptoms in men with LUTS and the low use of combination OAB treatments
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