5,926 research outputs found
Shock propagation in locally driven granular systems
We study shock propagation in a system of initially stationary hard-spheres
that is driven by a continuous injection of particles at the origin. The
disturbance created by the injection of energy spreads radially outwards
through collision between particles. Using scaling arguments, we determine the
exponent characterizing the power law growth of this disturbance in all
dimensions. The scaling functions describing the various physical quantities
are determined using large scale event driven simulations in two and three
dimensions for both the elastic and the inelastic system. The results are shown
to describe well the data from two different experiments on granular systems
that are similarly driven.Comment: 8 pages, 9 figure
Timely and reliable packets delivery over Internet of Vehicles (IoVs) for road accidents prevention: a cross-layer approach
With the envisioned era of Internet of Things (IoTs), all aspects of Intelligent Transportation Systems (ITS) will be connected to improve transport safety, relieve traffic congestion, reduce air pollution, enhance the comfort of transportation and significantly reduce road accidents. In IoVs, regular exchange of current position, direction, velocity, etc., enables mobile vehicles to predict an upcoming accident and alert the human drivers in time or proactively take precautionary actions to avoid the accident. The actualization of this concept requires the use of channel access protocols that can guarantee reliable and timely broadcast of safety messages. This paper investigates the application of network coding concept to increase content of every transmission and achieve improved broadcast reliability with less number of retransmission. In particular, we proposed Code Aided Retransmission-based Error Recovery (CARER) scheme, introduced an RTB/CTB handshake to overcome hidden node problem and reduce packets collision rate. In order to avoid broadcast storm problem associated with the use of RTB/CTB packet in a broadcast transmission, we developed a rebroadcasting metric used to successfully select a vehicle to rebroadcast the encoded message. The performance of CARER protocol is clearly shown with detailed theoretical analysis and further validated with simulation experiments
The prevalence of domestic violence among pregnant women in Nigeria: a systematic review.
To identify, appraise, and synthesize research evidence on the prevalence of domestic violence (DV) among pregnant women in Nigeria. We conducted a systematic review of all published studies between April 2004 and June 2016. Comprehensive searches were conducted on electronic databases such as PubMed, CINAHL, Global Health, MEDLINE, PsycINFO, Directory of Open Access Journals, Google Scholar, and electronic libraries of the authors' institution. Identified articles were screened in two stages against the inclusion criteria with titles and abstract screened first followed by full-text screening. Selected articles were assessed using the "guidelines for evaluating prevalence studies," and findings were synthesized narratively. Among 19 studies that met the inclusion criteria, two articles were excluded due to low methodological quality and 17 articles were included in the review. The prevalence of DV during pregnancy in Nigeria ranged between 2.3% and 44.6% with lifetime prevalence rates ranging between 33.1% and 63.2%. Physical, sexual, psychological, and verbal abuses were the most frequent types of DV reported in this review. The most common perpetrators were husbands, as reported in 11 of the 17 studies. Pregnant women between the ages of 20 and 30 years were the most common victims of DV. Our review suggests high prevalence of DV in pregnancy among women in Nigeria and higher lifetime prevalence. However, determining an overall, synthesized accurate prevalence rate of DV within this population based on existing evidence presents a challenge. The findings have important implications for stakeholders such as planners, policy makers, maternity care providers, and researchers in public health and social policy at national, regional, and international levels toward combating the issue. OBJECTIVE METHOD RESULTS CONCLUSIO
Patients’ Views: Peer Support Worker On Inpatient Wards
Purpose: To explore patients’ experiences of intentional mental health peer support (PS)
Design/methodology/approach: Seven in depth interviews were carried out by an independent researcher with individual inpatients who volunteered via a PS worker following leaflet and poster distribution explaining the research on the two wards. Each recorded interview of thirteen questions was transcribed verbatim by the researcher and analysis identified common themes across the interviews.
Findings: An overarching theme of communication with patients was identified together with six main themes: person centeredness, practical support, building connections, emotional support, modelling hope, and recovery interventions. There were no negative comments expressed by interviewees.
Research limitations/implications: Small scale qualitative research allows in-depth exploration of experiences which is valuable in informing the further development of peer support.
Originality/value: There are very few published reports of inpatient experiences of peer support in inpatient settings
TGFβ1 orchestrates renal fibrosis following Escherichia coli pyelonephritis
Renal scarring after pyelonephritis is linked to long-term health risks for hypertension and chronic kidney disease. Androgen exposure increases susceptibility to, and severity of, uropathogenic Escherichia coli (UPEC) pyelonephritis and resultant scarring in both male and female mice, while anti-androgen therapy is protective against severe urinary tract infection (UTI) in these models. This work employed androgenized female C57BL/6 mice to elucidate the molecular mechanisms of post-infectious renal fibrosis and to determine how these pathways are altered by the presence of androgens. We found that elevated circulating testosterone levels primed the kidney for fibrosis by increasing local production of TGFβ1 before the initiation of UTI, altering the ratio of transcription factors Smad2 and Smad3 and increasing the presence of mesenchymal stem cell (MSC)-like cells and Gli1 + activated myofibroblasts, the cells primarily responsible for deposition of scar components. Increased production of TGFβ1 and aberrations in Smad2:Smad3 were maintained throughout the course of infection in the presence of androgen, correlating with renal scarring that was not observed in non-androgenized female mice. Pharmacologic inhibition of TGFβ1 signaling blunted myofibroblast activation. We conclude that renal fibrosis after pyelonephritis is exacerbated by the presence of androgens and involves activation of the TGFβ1 signaling cascade, leading to increases in cortical populations of MSC-like cells and the Gli1 + activated myofibroblasts that are responsible for scarring
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Palbociclib plus letrozole as first-line therapy in estrogen receptor-positive/human epidermal growth factor receptor 2-negative advanced breast cancer with extended follow-up.
PurposeIn the initial PALOMA-2 (NCT01740427) analysis with median follow-up of 23 months, palbociclib plus letrozole significantly prolonged progression-free survival (PFS) in women with estrogen receptor-positive (ER+)/human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (ABC) [hazard ratio (HR) 0.58; P < 0.001]. Herein, we report results overall and by subgroups with extended follow-up.MethodsIn this double-blind, phase 3 study, post-menopausal women with ER+/HER2- ABC who had not received prior systemic therapy for their advanced disease were randomized 2:1 to palbociclib-letrozole or placebo-letrozole. Endpoints include investigator-assessed PFS (primary), safety, and patient-reported outcomes (PROs).ResultsAfter a median follow-up of approximately 38 months, median PFS was 27.6 months for palbociclib-letrozole (n = 444) and 14.5 months for placebo-letrozole (n = 222) (HR 0.563; 1-sided P < 0.0001). All subgroups benefited from palbociclib treatment. The improvement of PFS with palbociclib-letrozole was maintained in the next 2 subsequent lines of therapy and delayed the use of chemotherapy (40.4 vs. 29.9 months for palbociclib-letrozole vs. placebo-letrozole). Safety data were consistent with the known profile. Patients' quality of life was maintained.ConclusionsWith approximately 15 months of additional follow-up, palbociclib plus letrozole continued to demonstrate improved PFS compared with placebo plus letrozole in the overall population and across all patient subgroups, while the safety profile remained favorable and quality of life was maintained. These data confirm that palbociclib-letrozole should be considered the standard of care for first-line therapy in patients with ER+/HER2- ABC, including those with low disease burden or long disease-free interval. Sponsored by Pfizer; ClinicalTrials.gov: NCT01740427
High resolution spectroscopy for Cepheids distance determination. V. Impact of the cross-correlation method on the p-factor and the gamma-velocities
The cross correlation method (hereafter CC) is widely used to derive the
radial velocity curve of Cepheids when the signal to noise of the spectra is
low. However, if it is used with the wrong projection factor, it might
introduce some biases in the Baade-Wesselink (hereafter BW) methods of
determining the distance of Cepheids. In addition, it might affect the average
value of the radial velocity curve (or gamma-velocity) important for Galactic
structure studies. We aim to derive a period-projection factor relation
(hereafter Pp) appropriate to be used together with the CC method. Moreover, we
investigate whether the CC method can explain the misunderstood previous
calculation of the K-term of Cepheids. We observed eight galactic Cepheids with
the HARPS spectrograph. For each star, we derive an interpolated CC radial
velocity curve using the HARPS pipeline. The amplitudes of these curves are
used to determine the correction to be applied to the semi-theoretical
projection factor derived in Nardetto et al. (2007). Their average value (or
gamma-velocity) are also compared to the center-of-mass velocities derived in
Nardetto et al. (2008). The correction in amplitudes allows us to derive a new
Pp relation: p = [-0.08+-0.05] log P +[1.31+-0.06]. We also find a negligible
wavelength dependence (over the optical range) of the Pp relation. We finally
show that the gamma-velocity derived from the CC method is systematically
blue-shifted by about 1.0 +- 0.2km/s compared to the center-of-mass velocity of
the star. An additional blue-shift of 1.0km/s is thus needed to totally explain
the previous calculation of the K-term of Cepheids (around 2km/s). The new Pp
relation we derived is a solid tool for the distance scale calibration
(abridged).Comment: Comments : 9 pages, 3 Postscript figures, 5 Tables, accepted for
publication in A&
Results of the ROTOR-program. I. The long-term photometric variability of classical T Tauri stars
We present a unique, homogeneous database of photometric measurements for
Classical T Tauri stars extending up to 20 years. The database contains more
than 21,000 UBVR observations of 72 CTTs. All the data were collected within
the framework of the ROTOR-program at Mount Maidanak Observatory (Uzbekistan)
and together they constitute the longest homogeneous, accurate record of TTS
variability ever assembled. We characterize the long term photometric
variations of 49 CTTs with sufficient data to allow a robust statistical
analysis and propose an empirical classification scheme. Several patterns of
long term photometric variability are identified. The most common pattern,
exhibited by a group of 15 stars which includes T Tau itself, consists of low
level variability (Delta(V)<=0.4mag) with no significant changes occurring from
season to season over many years. A related subgroup of 22 stars exhibits a
similar stable long term variability pattern, though with larger amplitudes (up
to Delta(V)~1.6 mag). Besides these representative groups, we identify three
smaller groups of 3-5 stars each which have distinctive photometric properties.
The long term variability of most CTTs is fairly stable and merely reflects
shorter term variability due to cold and hot surface spots. Only a small
fraction of CTTs undergo significant brightness changes on the long term
(months, years), which probably arise from slowly varying circumstellar
extinction.Comment: 16 pages, 11 figures. Astron. Astrophys., in pres
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