2,255 research outputs found
Modeling the lasing spectra of InAs/InP Quantum dash lasers
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98746/1/ApplPhysLett_98_101105.pd
The importance of the merging activity for the kinetic polarization of the Sunyaev-Zel'dovich signal from galaxy clusters
The polarization sensitivity of the upcoming millimetric observatories will
open new possibilities for studying the properties of galaxy clusters and for
using them as powerful cosmological probes. For this reason it is necessary to
investigate in detail the characteristics of the polarization signals produced
by their highly ionized intra-cluster medium (ICM). This work is focussed on
the polarization effect induced by the ICM bulk motions, the so-called kpSZ
signal, which has an amplitude proportional to the optical depth and to the
square of the tangential velocity. In particular we study how this polarization
signal is affected by the internal dynamics of galaxy clusters and what is its
dependence on the physical modelling adopted to describe the baryonic
component. This is done by producing realistic kpSZ maps starting from the
outputs of two different sets of high-resolution hydrodynamical N-body
simulations. The first set (17 objects) follows only non-radiative
hydrodynamics, while for each of 9 objects of the second set we implement four
different kinds of physical processes. Our results shows that the kpSZ signal
turns out to be a very sensitive probe of the dynamical status of galaxy
clusters. We find that major merger events can amplify the signal up to one
order of magnitude with respect to relaxed clusters, reaching amplitude up to
about 100 nuK. This result implies that the internal ICM dynamics must be taken
into account when evaluating this signal because simplicistic models, based on
spherical rigid bodies, may provide wrong estimates. Finally we find that the
dependence on the physical modelling of the baryonic component is relevant only
in the very inner regions of clusters.Comment: 13 pages, 7 figures, submitted to A&
Treatment strategies for women with WHO group II anovulation: systematic review and network meta-analysis
Objective: To compare the effectiveness of alternative first line treatment options for women with WHO group II anovulation wishing to conceive. Design: Systematic review and network meta-analysis. Data Sources: Cochrane Central Register of Controlled Trials, Medline, and Embase, up to 11 April 2016. Study Selection: Randomised controlled trials comparing eight ovulation induction treatments in women with WHO group II anovulation: clomiphene, letrozole, metformin, clomiphene and metformin combined, tamoxifen, gonadotropins, laparoscopic ovarian drilling, and placebo or no treatment. Study quality was measured on the basis of the methodology and categories described in the Cochrane Collaboration Handbook. Pregnancy, defined preferably as clinical pregnancy, was the primary outcome; live birth, ovulation, miscarriage, and multiple pregnancy were secondary outcomes. Results: Of 2631 titles and abstracts initially identified, 57 trials reporting on 8082 women were included. All pharmacological treatments were superior to placebo or no intervention in terms of pregnancy and ovulation. Compared with clomiphene alone, both letrozole and the combination of clomiphene and metformin showed higher pregnancy rates (odds ratio 1.58, 95% confidence interval 1.25 to 2.00; 1.81, 1.35 to 2.42; respectively) and ovulation rates (1.99, 1.38 to 2.87; 1.55, 1.02 to 2.36; respectively). Letrozole led to higher live birth rates when compared with clomiphene alone (1.67, 1.11 to 2.49). Both letrozole and metformin led to lower multiple pregnancy rates compared with clomiphene alone (0.46, 0.23 to 0.92; 0.22, 0.05 to 0.92; respectively). Conclusions: In women with WHO group II anovulation, letrozole and the combination of clomiphene and metformin are superior to clomiphene alone in terms of ovulation and pregnancy. Compared with clomiphene alone, letrozole is the only treatment showing a significantly higher rate of live birth.Rui Wang, Bobae V Kim, Madelon van Wely, Neil P Johnson, Michael F Costello, Hanwang Zhang, Ernest Hung Yu Ng, Richard S Legro, Siladitya Bhattacharya, Robert J Norman, Ben Willem J Mo
An enhanced surface passivation effect in InGaN/GaN disk-in-nanowire light emitting diodes for mitigating Shockley-Read-Hall recombination
We present a detailed study of the effects of dangling bond passivation and the comparison of different sulfide passivation processes on the properties of InGaN/GaN quantum-disk (Qdisk)-in-nanowire based light emitting diodes (NW-LEDs). Our results demonstrated the first organic sulfide passivation process for nitride nanowires (NWs). The results from Raman spectroscopy, photoluminescence (PL) measurements, and X-ray photoelectron spectroscopy (XPS) showed that octadecylthiol (ODT) effectively passivated the surface states, and altered the surface dynamic charge, and thereby recovered the band-edge emission. The effectiveness of the process with passivation duration was also studied. Moreover, we also compared the electro-optical performance of NW-LEDs emitting at green wavelength before and after ODT passivation. We have shown that the ShockleyâReadâHall (SRH) non-radiative recombination of NW-LEDs can be greatly reduced after passivation by ODT, which led to a much faster increasing trend of quantum efficiency and higher peak efficiency. Our results highlighted the possibility of employing this technique to further design and produce high performance NW-LEDs and NW-lasers
Some constraints on neutral heavy leptons from flavor-conserving decays of the Z boson
Small neutrino masses can arise in some grand unified models or superstring
theories. We consider a model with an enhanced fermion sector containing Dirac
neutral heavy leptons. The dependence on the mass and mixing parameters of
these new fermions is investigated for several measurable quantities. We study
the flavor-conserving leptonic decays of the Z boson and universality breaking
in these decays. We also consider the W boson mass dependence on neutral heavy
lepton parameters.Comment: 20 pages, Revtex 3.0, 6 uuencoded and compressed postscript figures
included. Compressed postscript file of paper, including figures, also
available by anonymous ftp at
ftp://ftp.physics.carleton.ca/pub/theory/gour/ocipc9411.ps.Z . Accepted for
publication in Phys. Rev. D
Phenomenology of neutral heavy leptons
We continue our previous work on the flavour-conserving leptonic decays of
the Z boson with neutral heavy leptons (NHL's) in the loops by considering box,
vertex, and self-energy diagrams for the muon decay. By inclusion of these
loops (they contribute to the input parameter M_W) we can probe the full
parameter space spanned by the so-called flavour-conserving mixing parameters
ee_(mix), \mu\mu_(mix), \tau\tau_(mix) in a superstring-inspired model of
neutrino mass. We compare the results of our analysis with the existing work in
this field and conclude that flavour-conserving decays have certain advantages
over traditionally considered flavour-violating ones.Comment: submitted to Phys. Rev. D, 30 pages, 9 figures (ps), REVTE
Treatment strategies for women with WHO group II anovulation : systematic review and network meta-analysis
Funding: The work was supported by an Australian government research training programme scholarship (held by RW) and the Australian National Health and Medical Research Council funded Centre for Research Excellence in Polycystic Ovary Syndrome (APP1078444).Peer reviewedPublisher PD
Cochlin, Intraocular Pressure Regulation and Mechanosensing
Fluid shear modulates many biological properties. How shear mechanosensing occurs in the extracellular matrix (ECM) and is transduced into cytoskeletal change remains unknown. Cochlin is an ECM protein of unknown function. Our investigation using a comprehensive spectrum of cutting-edge techniques has resulted in following major findings: (1) over-expression and down-regulation of cochlin increase and decrease intraocular pressure (IOP), respectively. The overexpression was achieved in DBA/2J-Gpnmb+/SjJ using lentiviral vectors, down-regulation was achieved in glaucomatous DBA/2J mice using targeted disruption (cochlin-null mice) and also using lentiviral vector mediated shRNA against cochlin coding region; (2) reintroduction of cochlin in cochlin-null mice increases IOP; (3) injection of exogenous cochlin also increased IOP; (4) increasing perfusion rates increased cochlin multimerization, which reduced the rate of cochlin proteolysis by trypsin and proteinase K; The cochlin multimerization in response to shear stress suggests its potential mechanosensing. Taken together with previous studies, we show cochlin is involved in regulation of intraocular pressure in DBA/2J potentially through mechanosensing of the shear stress
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