ABSTRACT
Observations of the redshifted 21-cm hyperfine line of neutral hydrogen from early phases of the Universe such as Cosmic Dawn and the Epoch of Reionization promise to open a new window onto ...the early formation of stars and galaxies. We present the first upper limits on the power spectrum of redshifted 21-cm brightness temperature fluctuations in the redshift range z = 19.8–25.2 (54–68 MHz frequency range) using 14 h of data obtained with the LOFAR-Low Band Antenna (LBA) array. We also demonstrate the application of a multiple pointing calibration technique to calibrate the LOFAR-LBA dual-pointing observations centred on the North Celestial Pole and the radio galaxy 3C220.3. We observe an unexplained excess of $\sim 30\!-\!50{{\ \rm per\ cent}}$ in Stokes / noise compared to Stokes V for the two observed fields, which decorrelates on ≳12 s and might have a physical origin. We show that enforcing smoothness of gain errors along frequency direction during calibration reduces the additional variance in Stokes I compared Stokes V introduced by the calibration on sub-band level. After subtraction of smooth foregrounds, we achieve a 2σ upper limit on the 21-cm power spectrum of $\Delta _{21}^2 \lt (14561\, \text{mK})^2$ at $k\sim 0.038\, h\, \text{cMpc}^{-1}$ and $\Delta _{21}^2 \lt (14886\, \text{mK})^2$ at $k\sim 0.038 \, h\, \text{cMpc}^{-1}$ for the 3C220 and NCP fields respectively and both upper limits are consistent with each other. The upper limits for the two fields are still dominated by systematics on most k modes.
Context:
Vitamin D affects bone and muscle health and likely reduces the risk of falls in the elderly.
Objective:
The aim of this systematic review is to summarize the existing evidence on vitamin D ...use and the risk of falls.
Data Sources:
We searched electronic databases from inception through August 2010.
Study Selection:
Eligible studies were randomized controlled trials in which the intervention was vitamin D and the incidence of falls was reported.
Data Extraction:
Reviewers working in duplicate and independently extracted study characteristics, quality, and outcomes data.
Data Synthesis:
Odds ratio and associated 95% confidence interval were estimated from each study and pooled using the random effects model.
Results:
We found 26 eligible trials of moderate quality that enrolled 45,782 participants, the majority of which were elderly and female. Vitamin D use was associated with statistically significant reduction in the risk of falls (odds ratio for suffering at least one fall, 0.86; 95% confidence interval, 0.77–0.96). This effect was more prominent in patients who were vitamin D deficient at baseline and in studies in which calcium was coadministered with vitamin D. The quality of evidence was low to moderate because of heterogeneity and publication bias.
Conclusions:
Vitamin D combined with calcium reduces the risk of falls. The reduction in studies without calcium coadministration did not reach statistical significance. The majority of the evidence is derived from trials enrolling elderly women.
The use of left atrial appendage occlusion (LAAO) devices have gained prominence as an alternative to long‐term anticoagulation therapy in patients with atrial fibrillation at risk of stroke and high ...risk of bleeding. While these devices have shown efficacy in reducing stroke risk, there have been reported cases of embolization of the Watchman device. There are very few cases of successful percutaneous retrieval of embolized Watchman devices from the left ventricle (LV), as many of these cases require open heart surgery for safe removal. We are presenting a case of an 80‐year‐old male whose Watchman device embolized to the LV and was entrapped on the LV papillary muscle that was then successfully retrieved via percutaneous methods, which shows the percutaneous options remain a viable strategy to retrieve LAAO devices from the LV.
Broadband circularly polarised square slot antenna excited by a coplanar waveguide feed with enhanced axial ratio bandwidth (ARBW) is proposed, designed and experimentally studied. Larger than 21% 3 ...dB ARBW can be attained by using asymmetric feed and implementing a T-shaped grounded stub from the left side of the square slot in orthogonal direction towards the slot centre. To further enhance the 3 dB ARBW of the proposed slot antenna, a pair of equal grounded L-shaped strips with different sizes is embedded at the top right corner of the square slot. Small L-shaped grounded strip plays an important role for merging two closely spaced multi-resonant modes, generated by the combined effect of asymmetric feed with T-shaped grounded stub and with large L-shaped strip. Overall size of the proposed antenna is 40 × 40 × 1.6 mm3. Measured value shows that the impedance bandwidth and 3 dB ARBW of the designed antenna are 73.39% (5.02–10.84 GHz) and 58.08% (5.07–9.22 GHz), respectively. Good agreement is achieved between simulated and measured results.
Graphene–polyaniline composites have been synthesized using simple chemical procedure in two different ways (i) by mixing of the pre-synthesized graphene and polyaniline nanofibers and (ii) by in ...situ polymerization in presence of graphite oxide followed by further reduction. Detailed optical spectroscopic studies of the synthesized composites along with the pristine polyaniline nanofibers were performed by Fourier transformed infrared spectroscopy and UV–vis spectroscopy. The structural and morphological characterizations were performed by X-ray diffraction, transmission electron microscope measurements and field emission scanning electron microscope measurements, respectively while the chemical characters were studied by X-ray photoelectron spectroscopic measurement. The graphene–polyaniline composite retained the photoluminescence property of the as synthesized polyaniline nanofibers. The electron field emission property of the composite showed marked improvement compared to pristine polyaniline fibers with a turn-on field as low as 3.91
V/μm at a current density of 1
μA/cm
2. The field enhancement factor was found to be 7012 which is much higher for the case of a polymer based composite.
Background
While people with intellectual disability (ID) face disparities relating to sexual and reproductive health (SRH) services, little is known about the role of family caregivers who assist ...women and girls with ID access SRH services. This scoping review examined the findings of studies to elucidate the role of family caregivers with regard to SRH for women and girls with ID.
Method
We used Arksey and O'Malley's six‐stage scoping framework, with Levac, Colquhoun and O'Brien's revisions, to evaluate identified sources. We searched three electronic databases, six ID journals and reference lists in full‐text articles. Inclusion criteria included (1) primary and secondary source research studies in peer‐reviewed journals; (2) published in English; (3) all research methodologies (i.e. qualitative, quantitative, mixed methods and systematic reviews or commentaries); (4) published between 2000 and 2016; and (5) studies from any country.
Results
The search yielded 2062 studies; 57 articles met inclusion criteria. Most studies employed purposive, convenience or criterion sampling. Participants included people with ID, family caregivers, paid caregivers and health‐care professionals. Findings were summarised thematically: (1) menstruation and menopause; (2) vaccinations and preventive screenings; (3) supporting sexuality and healthy relationships; (4) coordinating with health‐care providers and (5) contraception and sterilisation.
Conclusions
Findings from this scoping review underscore the need for more and better‐quality research, including how family caregivers assist women and girls with ID access perinatal and preventive SRH services and sexual abuse education. Family caregivers, women and girls with ID and health‐care providers need increased access to information about SRH.
Summary A rare case of tuberculous osteomyelitis mandible with pathological fracture has been reported. The problems in diagnosis and principles of management have been highlighted. Accurate, repair ...of mucosal tear and longer period of immobilization are necessary.
An analytical–numerical method, based on the use of wavelet spectral finite elements (WSFE), is presented for studying the nonlinear interaction of flexural waves with a breathing crack present in a ...slender beam. The cracked beam is discretized using wavelet spectral finite elements which use compactly supported Daubechies scaling functions for approximating the temporal dependence of the transverse displacement. Rotational spring is used to model the open crack condition, and behavior of the beam in closed-crack condition is assumed to be similar to that of an intact beam. An intermittent switching between the open- and closed-crack conditions simulates crack-breathing, leading to a set of nonlinear equations which is solved using an iterative method. Results of the proposed method are compared with those obtained using the Fourier spectral finite element (FSFE) and 1D finite element (FE) methods, which show a close agreement. Existence of the higher-order harmonic components, indicative of the crack-induced bilinearity, is confirmed in the frequency domain response. Moreover, the time domain analysis reveals separation of harmonics resulting from the dispersive nature of the waveguide, which is further used for localizing the damage. A parametric study is presented to bring out the influence of crack-severity and -location on the extent of harmonic separation and on the relative strength of higher order harmonic. In addition to elaborating the use of WSFE in addressing the nonlinear wave-damage interaction, results of the present investigation can be potentially useful in devising strategies for an inverse analysis.
•Nonlinear interaction of flexural wave with breathing crack is modeled analytically.•Wave response is obtained by iterative use of wavelet domain spectral finite element method (WSFE).•Results are corroborated with time domain 1-D finite element method (FEM).•The developed scheme being semi-analytical possess potential for inverse problem solution.
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