367 research outputs found
Information transfer through disordered media by diffuse waves
We consider the information content h of a scalar multiple-scattered, diffuse
wave field and the information capacity C of a communication
channel that employs diffuse waves to transfer the information through a
disordered medium. Both h and C are shown to be directly related to the
mesoscopic correlations between the values of at different
positions in space, arising due to the coherent nature of the wave.
For the particular case of a communication channel between two identical linear
arrays of equally-spaced transmitters/receivers (receiver spacing a),
we show that the average capacity and obtain explicit analytic
expressions for in the limit of and ,
where , is the wavelength, and is the mean
free path. Modification of the above results in the case of finite but large n
and is discussed as well.Comment: REVTeX 4, 12 pages, 7 figure
Multimorbidity phenotypes in patients presenting to the emergency department with possible acute coronary syndrome
Background: Multimorbidity (> 2 conditions) increases the risk of adverse outcomes and challenges health care systems for patients with acute coronary syndrome (ACS). These complications may be partially attributed to ACS clinical care which is driven by single-disease-based practice guidelines; current guidelines do not consider multimorbidity. Objectives: To identify multimorbidity phenotypes (combinations of conditions) with suspected ACS. We hypothesized that: 1) subgroups of patients with similar multimorbidity phenotypes could be identified, 2) classes would differ according to diagnosis, and 3) class membership would differ by sex, age, functional status, family history, and discharge diagnosis. Methods: This was a secondary analysis of data from a large multi-site clinical study of patients with suspected ACS. Conditions were determined by items on the Charlson Comorbidity Index and the ACS Patient Information Questionnaire. Latent class analysis was used to identify phenotypes. Results: The sample (n = 935) was predominantly male (68%) and middle-aged (mean= 59 years). Four multimorbidity phenotypes were identified: 1) high multimorbidity (Class 1) included hyperlipidemia, hypertension (HTN), obesity, diabetes, and respiratory disorders (COPD or asthma); 2) low multimorbidity (Class 2) included only obesity; 3) cardiovascular multimorbidity (Class 3) included HTN, hyperlipidemia, and coronary heart disease; and 4) cardio-oncology multimorbidity (Class 4) included HTN, hyperlipidemia, and cancer. Patients ruled-in for ACS primarily clustered in Classes 3 and 4 (OR 2.82, 95% CI 1.95–4.05, p = 0.001 and OR 1.76, 95% CI 1.13–2.74, p = 0.01). Conclusion: Identifying and understanding multimorbidity phenotypes may assist with risk-stratification and better triage of high-risk patients in the emergency department
An unusual cause of acute cardiogenic shock in the operating room
A 51-year-old man with a renal carcinoma with inferior vena cava (IVC) invasion was referred to our hospital for the performance of a radical nephrectomy with IVC thrombus excision. To prevent embolism, an IVC filter was implanted the day before surgery below the suprahepatic veins. On nephrectomy completion, the clinical status of the patient started to deteriorate and an unsuccessful attempt was made to excise the IVC thrombus. The patient developed profound refractory hypotension without significant bleeding and worsening splanchnic stasis was noted. A transesophageal echocardiogram was immediately performed in the operating room, revealing a hemispheric mass protruding from the IVC ostium to the right atrium, completely blocking all venous return. Volume depletion was evident by low left and right atrial volumes and increased septum mobility. No other abnormalities were found that could explain the shock, namely ventricular dysfunction or valvular disease. Cardiac surgery consultation was immediately obtained, ultimately deciding to perform a median sternotomy with direct exploration of right atrium. Under cardiopulmonary bypass, a 6-cm long thrombotic mass was identified, involving the IVC filter, blocking all lower body venous return; the removal of the mass reversed the shock. The patient had an uneventful recovery. Adverse outcomes associated with IVC filters are common. Our case highlights the importance of a team approach to rapid changes in hemodynamic status in the operating room, including the surgeon, the anesthesiologist, and the cardiologist. It also emphasizes the pivotal role of transesophageal echocardiogram in the clinical evaluation of severely unstable patien
Choline supplementation in children with fetal alcohol spectrum disorders has high feasibility and tolerability
There are no biological treatments for fetal alcohol spectrum disorders (FASDs), lifelong conditions associated with physical anomalies, brain damage, and neurocognitive abnormalities. In preclinical studies, choline partially ameliorates memory and learning deficits from prenatal alcohol exposure. This phase I pilot study evaluated the feasibility, tolerability, and potential adverse effects of choline supplementation in children with FASD. We hypothesized that choline would be well tolerated with minimal adverse events. The study design was a double-blind, randomized, placebo-controlled trial. Participants included 20 children aged 2.5 to 4.9 years with prenatal alcohol exposure and FASD diagnoses. Participants were randomly assigned to 500 mg choline or placebo daily for 9 months (10 active, 10 placebo). Primary outcome measures included feasibility, tolerability, adverse effects, and serum choline levels. Seventeen participants completed the study. Compliance was 82% to 87%, as evidenced by parent-completed log sheets and dose counts. Periodic 24-hour dietary recalls showed no evidence of dietary confounding. Adverse events were minimal and were equivalent in the active and placebo arms with the exception of fishy body odor, which occurred only in the active group. There were no serious adverse events to research participants. This phase I pilot study demonstrates that choline supplementation at 500 mg/d for 9 months in children aged 2 to 5 years is feasible and has high tolerability. Further examination of the efficacy of choline supplementation in FASD is currently underway
Weak Localization Effect in Superconductors by Radiation Damage
Large reductions of the superconducting transition temperature and
the accompanying loss of the thermal electrical resistivity (electron-phonon
interaction) due to radiation damage have been observed for several A15
compounds, Chevrel phase and Ternary superconductors, and in
the high fluence regime. We examine these behaviors based on the recent theory
of weak localization effect in superconductors. We find a good fitting to the
experimental data. In particular, weak localization correction to the
phonon-mediated interaction is derived from the density correlation function.
It is shown that weak localization has a strong influence on both the
phonon-mediated interaction and the electron-phonon interaction, which leads to
the universal correlation of and resistance ratio.Comment: 16 pages plus 3 figures, revtex, 76 references, For more information,
Plesse see http://www.fen.bilkent.edu.tr/~yjki
Models for Type Ia supernovae and related astrophysical transients
We give an overview of recent efforts to model Type Ia supernovae and related
astrophysical transients resulting from thermonuclear explosions in white
dwarfs. In particular we point out the challenges resulting from the
multi-physics multi-scale nature of the problem and discuss possible numerical
approaches to meet them in hydrodynamical explosion simulations and radiative
transfer modeling. We give examples of how these methods are applied to several
explosion scenarios that have been proposed to explain distinct subsets or, in
some cases, the majority of the observed events. In case we comment on some of
the successes and shortcoming of these scenarios and highlight important
outstanding issues.Comment: 20 pages, 2 figures, review published in Space Science Reviews as
part of the topical collection on supernovae, replacement corrects typos in
the conclusions sectio
Four-year follow-up of a randomized controlled trial of choline for neurodevelopment in fetal alcohol spectrum disorder
Background: Despite the high prevalence of fetal alcohol spectrum disorder (FASD), there are few interventions targeting its core neurocognitive and behavioral deficits. FASD is often conceptualized as static and permanent, but interventions that capitalize on brain plasticity and critical developmental windows are emerging. We present a long-term follow-up study evaluating the neurodevelopmental effects of choline supplementation in children with FASD 4 years after an initial efficacy trial. Methods: The initial study was a randomized, double-blind, placebo-controlled trial of choline vs. placebo in 2-5-year-olds with FASD. Participants include 31 children (16 placebo; 15 choline) seen 4 years after trial completion. The mean age at follow-up was 8.6 years. Diagnoses were 12.9% fetal alcohol syndrome (FAS), 41.9% partial FAS, and 45.1% alcohol-related neurodevelopmental disorder. The follow-up included measures of intelligence, memory, executive functioning, and behavior. Results: Children who received choline had higher non-verbal intelligence, higher visual-spatial skill, higher working memory ability, better verbal memory, and fewer behavioral symptoms of attention deficit hyperactivity disorder than the placebo group. No differences were seen for verbal intelligence, visual memory, or other executive functions. Conclusions: These data support choline as a potential neurodevelopmental intervention for FASD and highlight the need for long-term follow-up to capture treatment effects on neurodevelopmental trajectories. Trial registration: ClinicalTrials.Gov #NCT01149538; Registered: June 23, 2010; first enrollment July 2, 2010
Cichlid biogeography: comment and review
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72313/1/j.1467-2979.2004.00148.x.pd
Forearm rotation improves after corrective osteotomy in patients with symptomatic distal radius malunion
Objectives: Distal radius malunion can result in pain and functional complaints. One of the functional problems that can affect daily life is impaired forearm rotation. The primary aim of this study was to investigate the effect of corrective osteotomy for distal radius malunion on forearm rotation at 12 months after surgery. We secondarily studied the effect on grip strength, radiological measurements, and patient-reported outcome measurements (PROMs). Patients and methods: This cohort study analysed prospectively collected data of adult patients with symptomatic distal radius malunion. All patients underwent corrective osteotomy for malunion and were followed for 1 year. We measured forearm rotation (pronation and supination) and grip strength and analysed radiographs. PROMs consisted of the Patient-Rated Hand/Wrist Evaluation (PRWHE) questionnaire, Visual Analogue Scale for pain, and satisfaction with hand function. Results:Preoperative total forearm rotation was 112° (SD: 34°), of which supination of 49° (SD: 25°) was more impaired than pronation of 63° (SD: 17°). Twelve months after surgery, an unpaired Student's t-test showed a significant improvement of total forearm rotation to 142° (SD: 17°) (p < 0.05). Pronation improved to 72° (SD: 10°), and supination to 69° (SD: 13°) (p < 0.05). Grip strength, PROMs, as well as inclination and volar tilt on radiographs improved significantly during the first year after surgery (p < 0.05). Conclusion: In patients with reduced forearm rotation due to distal radius malunion, corrective osteotomy is an effective treatment that significantly improves forearm rotation. In addition, this intervention improves grip strength, the PRWHE-score, pain, and satisfaction with hand function.</p
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