996 research outputs found
Magnification and evolution bias of transient sources: GWs and SNIa
Third-generation gravitational wave (GW) observatories such as the Einstein
Telescope and Cosmic Explorer, together with the LSST survey at the Vera Rubin
Observatory, will yield an abundance of extra-galactic transient objects. This
opens the exciting possibility of using GW sources and Supernovae Type Ia
(SNIa) as luminosity distance tracers of large-scale structure for the first
time. The large volumes accessible to these surveys imply that we may need to
include relativistic corrections, such as lensing and Doppler magnification.
However, the amplitude of these effects depends on the magnification and
evolution biases of the transient sources, which are not yet understood. In
this paper we develop comprehensive frameworks to address and model these
biases for both populations of transient objects; in particular, we define how
to compute these biases for GW sources. We then analyse the impact of
magnification and evolution biases on the relativistic corrections and on the
angular power spectrum of these sources. We show that correct modelling and
implementation of these biases is crucial for measuring the cross-correlations
of transient sources at higher redshifts.Comment: 28 pages, 14 figures, 4 tables, comments welcom
The phenomenological approach to modeling the dark energy
In this mini-review we discuss first why we should investigate cosmological
models beyond LCDM. We then show how to describe dark energy or modified
gravity models in a fluid language with the help of one background and two
perturbation quantities. We review a range of dark energy models and study how
they fit into the phenomenological framework, including generalizations like
phantom crossing, sound speeds different from c and non-zero anisotropic
stress, and how these effective quantities are linked to the underlying
physical models. We also discuss the limits of what can be measured with
cosmological data, and some challenges for the framework.Comment: 44 pages, 5 figures; accepted review article to appear in a special
volume of the "Comptes Rendus de l'Academie des Sciences" about Dark Energy
and Dark Matte
The psychological cycle behind dental appointment attendance: a cross-sectional study of experiences, anticipations, and behavioral intentions
Objectives: This study explored a promising theoretical model to explain dental patients’ experiences and planning behavior for future appointments. The model predicts that patients pass through a ‘psychological cycle’ when undergoing a course of dental care: past appointment experiences influence their anticipations for future dental visits, which in turn affect behavioral intentions to attend appointments. Methods: Variables representing the hypothesized model stages and other potentially relevant context variables (dental anxiety, subjective oral health ratings, general anxiety, stress) were assessed by means of a cross-sectional online survey (n = 311). Multiple regression analyses were calculated to estimate the model's fit while controlling for potentially confounding factors. Results: Consistent with the hypothesized cycle, recollections of past appointment experiences influenced behavioral intentions to attend future appointments. This association was mediated by evaluations of prior visits and expectations for future appointments. The variables included within this model explained 42% of the variance in attendance intentions when controlling for the potential moderating effects of context variables. Conclusions: The findings highlight the contribution of cognitive factors, such as evaluations and expectations, to patients’ attendance intentions. This knowledge could help find ways to improve treatment expectations to foster better dental service utilization
Acupuncture for treating overactive bladder in adults
This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:
To assess the effects of acupuncture for treating OAB in adults; and summarise the principal findings of relevant economic evaluations
2016 deep space habitat designs in support of the Exploration Habitat Academic Innovation Challenge (X-Hab)
The X-HAB 2016: Medical Bay Thesis Report consists of the final presentation held on May 6th, 2016 with the current OSU X-HAB Faculty (Dr. Jacob, Dr. O'Hara) and several NASA correspondents. The Exploration Habitat Academic Innovation Challenge allows undergraduate students from various disciplines (engineering, architecture, etc.) to develop solutions to challenges faced in deep-space transit. The Integrated Medical Bay team of 2016 focused its efforts upon enhancing a currently existing analog habitat (ReHAB) with an automatized medical bay. The medical bay builds upon a finalist concept of the Fall 2015 Spacecraft Design course to deliver fast and quality medical care in case of emergency. The semi-automatic hydraulic system was designed and implemented through the application of material science, strength of materials, systems engineering and mechatronics
Corporate Social Responsibility and Islamic Financial Institutions (IFIs): Management Perceptions from IFIs in Bahrain
Islamic finance is gaining greater attention in the finance industry, and this paper analyses how Islamic financial institutions (IFIs) are responding to the welfare needs of society. Using interview data with managers and content analysis of the disclosures, this study attempts to understand management perceptions of corporate social
responsibility (CSR) in IFIs. A thorough understanding of CSR by managers, as evident in the interviews, has not been translated fully into practice. The partial use of IFIs’ potential role in social welfare would add further challenges in the era of financialisation
Determination of the mass of the neutron star in SMC X-1, LMC X-4 and Cen X-3 with VLT/UVES
We present the results of a spectroscopic monitoring campaign of the OB-star
companions to the eclipsing X-ray pulsars SMC X-1, LMC X-4 and Cen X-3.
High-resolution optical spectra obtained with UVES on the ESO Very Large
Telescope are used to determine the radial-velocity orbit of the OB
(super)giants with high precision. The excellent quality of the spectra
provides the opportunity to measure the radial-velocity curve based on
individual lines, and to study the effect of possible distortions of the line
profiles due to e.g. X-ray heating on the derived radial-velocity amplitude.
Several spectral lines show intrinsic variations with orbital phase. The
magnitude of these variations depends on line strength, and thus provides a
criterion to select lines that do not suffer from distortions. The undistorted
lines show a larger radial-velocity amplitude than the distorted lines,
consistent with model predictions. Application of our line-selection criteria
results in a mean radial-velocity amplitude K(Opt) of 20.2 +/- 1.1, 35.1 +/-
1.5, and 27.5 +/- 2.3 km/s (1 sigma errors), for the OB companion to SMC X-1,
LMC X-4 and Cen X-3, respectively. Adding information on the projected
rotational velocity of the OB companion (derived from our spectra), the
duration of X-ray eclipse and orbital parameters of the X-ray pulsar (obtained
from literature), we arrive at a neutron star mass of 1.06^{+0.11}_{-0.10},
1.25^{+0.11}_{-0.10} and 1.34^{+0.16}_{-0.14} M{sun} for SMC X-1, LMC X-4 and
Cen X-3, respectively. The mass of SMC X-1 is near the minimum mass (~1 M{sun})
expected for a neutron star produced in a supernova. We discuss the
implications of the measured mass distribution on the neutron-star formation
mechanism, in relation to the evolutionary history of the massive binaries.Comment: Accepted for publication in Astronomy and Astrophysic
Asymmetric triplex metallohelices with high and selective activity against cancer cells
Small cationic amphiphilic α-helical peptides are emerging as agents for the treatment of cancer and infection, but they are costly and display unfavourable pharmacokinetics. Helical coordination complexes may offer a three-dimensional scaffold for the synthesis of mimetic architectures. However, the high symmetry and modest functionality of current systems offer little scope to tailor the structure to interact with specific biomolecular targets, or to create libraries for phenotypic screens. Here, we report the highly stereoselective asymmetric self-assembly of very stable, functionalized metallohelices. Their anti-parallel head-to-head-to-tail ‘triplex’ strand arrangement creates an amphipathic functional topology akin to that of the active sub-units of, for example, host-defence peptides and p53. The metallohelices display high, structure-dependent toxicity to the human colon carcinoma cell-line HCT116 p53++, causing dramatic changes in the cell cycle without DNA damage. They have lower toxicity to human breast adenocarcinoma cells (MDA-MB-468) and, most remarkably, they show no significant toxicity to the bacteria methicillin-resistant Staphylococcus aureus and Escherichia coli.
At a glanc
Screening of Subtelomeric Rearrangements in 100 Korean Pediatric Patients with Unexplained Mental Retardation and Anomalies Using Subtelomeric FISH (Fluorescence In Situ Hybridization)
Rearrangements of the subtelomeric regions of chromosomes account for a significant proportion of the underlying genetic defects in both idiopathic mental retardation (MR) and multiple congenital anomalies. To detect the rearrangements, a set of subtelomeric fluorescence in situ hybridization (FISH) probes has been developed. The aim of this study was to reveal the frequency of subtelomeric rearrangements in Korean patients with MR or multiple anomalies. We performed a FISH study using a commercially available subtelomeric FISH probes on a series of unrelated Korean pediatric patients with MR or multiple anomalies without identifiable causes. We used a checklist to evaluate the developmental delay and/or MR. Patients who were shown to have chromosome abnormalities, metabolic disorders, or recognizable dysmorphic syndromes by clinical and laboratory findings were excluded. As a result, 100 patients were eligible for the Subtelomeric FISH study, and a total of 29 patients (29%) were suspected to have subtelomeric rearrangements on initial screening by the multiprobe FISH kit. Among theses, confirmatory FISH studies by using single locus-specific FISH probes were performed in 24 patients. One patient (a 10-yr-old girl) was confirmed to have rearrangement, deletion of the telomeric portion of the short arm of chromosome 4 (4p). Her clinical manifestation was compatible with Wolf-Hirschhorn syndrome, which is known to be caused by 4p deletion. The frequency of subtelomeric rearrangements in this study was 1.1% (1/95), lower than those previously reported (0.5-16.3%). We suggest that subtelomeric FISH test is a useful screening tool for patients with idiopathic MR and/or dysmorphism regardless of its false positive value
The synthesis, chain-packing simulation and long-term gas permeability of highly selective spirobifluorene-based polymers of intrinsic microporosity
Membranes composed of Polymers of Intrinsic Microporosity (SBF-PIMs) have potential for commercial gas separation. Here we report a combined simulation and experimental study to investigate the effect on polymer microporosity and gas permeability by placing simple substituents such as methyl, t-butyl and fused benzo groups onto PIMs derived from spirobifluorene (PIM-SBFs). It is shown that methyl or t-butyl substituents both cause a large increase in gas permeabilities with four methyl groups enhancing the concentration of ultramicropores (1.0 nm). Long-term ageing studies (>3.5 years) demonstrate the potential of PIM-SBFs as high-performance membrane materials for gas separations. In particular, the data for the PIM derived from tetramethyl substituted SBF reaches the proposed 2015 Robeson upper bound for O2/N2 and, hence, hold promise for the oxygen or nitrogen enrichment of air. Mixed gas permeation measurements for CO2/CH4 of the aged PIM-SBFs also demonstrate their potential for natural gas or biogas upgrading
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