Random Sequential Renormalization of Networks I: Application to Critical Trees

We introduce the concept of Random Sequential Renormalization (RSR) for arbitrary networks. RSR is a graph renormalization procedure that locally aggregates nodes to produce a coarse grained network. It is analogous to the (quasi-)parallel renormalization schemes introduced by C. Song {\it et al.} (Nature {\bf 433}, 392 (2005)) and studied more recently by F. Radicchi {\it et al.} (Phys. Rev. Lett. {\bf 101}, 148701 (2008)), but much simpler and easier to implement. In this first paper we apply RSR to critical trees and derive analytical results consistent with numerical simulations. Critical trees exhibit three regimes in their evolution under RSR: (i) An initial regime $N_0^{\nu}\lesssim N<N_0$, where $N$ is the number of nodes at some step in the renormalization and $N_0$ is the initial size. RSR in this regime is described by a mean field theory and fluctuations from one realization to another are small. The exponent $\nu=1/2$ is derived using random walk arguments. The degree distribution becomes broader under successive renormalization -- reaching a power law, $p_k\sim 1/k^{\gamma}$ with $\gamma=2$ and a variance that diverges as $N_0^{1/2}$ at the end of this regime. Both of these results are derived based on a scaling theory. (ii) An intermediate regime for $N_0^{1/4}\lesssim N \lesssim N_0^{1/2}$, in which hubs develop, and fluctuations between different realizations of the RSR are large. Crossover functions exhibiting finite size scaling, in the critical region $N\sim N_0^{1/2} \to \infty$, connect the behaviors in the first two regimes. (iii) The last regime, for $1 \ll N\lesssim N_0^{1/4}$, is characterized by the appearance of star configurations with a central hub surrounded by many leaves. The distribution of sizes where stars first form is found numerically to be a power law up to a cutoff that scales as $N_0^{\nu_{star}}$ with $\nu_{star}\approx 1/4$

Psychological Therapies in Patients with Irritable Bowel Syndrome: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background. Irritable bowel syndrome (IBS) is a poorly understood disease with few effective treatments. Psychosocial factors are believed to contribute to the pathogenesis of IBS. Objective. To evaluate the evidence for psychological therapies in IBS treatment. Methods. We searched six medical databases through February 6, 2014, for randomized controlled trials (RCTs) of psychological therapies for the treatment of IBS. Two independent reviewers identified the RCTs, extracted the data, and assessed trial quality. We used the random-effect model to pool standardized mean difference (SMD) and 95% confidence interval (CI) across trials. Results. 15 RCTs that mostly evaluated cognitive behavioral therapy were included. Psychological therapies were associated with improvement in IBS symptoms severity scales (SMD −0.618; 95% CI: −0.853 to −0.383), IBS-Quality of Life (SMD 0.604; 95% CI: 0.440 to 0.768), and abdominal pain (SMD −0.282; 95% CI: −0.562 to −0.001). No statistically significant effect was observed on diarrhea or constipation. Limitations. The trials were at increased risk of bias and the overall sample size was small leading to imprecision. Conclusion. Psychological therapies may improve the quality of life and symptom severity in IBS. The effect size noted is moderate to large and is clinically meaningful

Portrayal of organ donation and transplantation on American primetime television

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/86819/1/j.1399-0012.2011.01427.x.pd

Benefits and harms of oral anticoagulant therapy in chronic kidney disease: a systematic review and meta-analysis

Background: Effects of oral anticoagulation in chronic kidney disease (CKD) are uncertain. Purpose: To evaluate the benefits and harms of vitamin K antagonists (VKAs) and non–vitamin K oral anticoagulants (NOACs) in adults with CKD stages 3 to 5, including those with dialysis-dependent end-stage kidney disease (ESKD). Data Sources: English-language searches of MEDLINE, EMBASE, and Cochrane databases (inception to February 2019); review bibliographies; and ClinicalTrials.gov (25 February 2019). Study Selection: Randomized controlled trials evaluating VKAs or NOACs for any indication in patients with CKD that reported efficacy or bleeding outcomes. Data Extraction: Two authors independently extracted data, assessed risk of bias, and rated certainty of evidence. Data Synthesis: Forty-five trials involving 34 082 participants who received anticoagulation for atrial fibrillation (AF) (11 trials), venous thromboembolism (VTE) (11 trials), thromboprophylaxis (6 trials), prevention of dialysis access thrombosis (8 trials), and cardiovascular disease other than AF (9 trials) were included. All but the 8 trials involving patients with ESKD excluded participants with creatinine clearance less than 20 mL/min or estimated glomerular filtration rate less than 15 mL/min/1.73 m2. In AF, compared with VKAs, NOACs reduced risks for stroke or systemic embolism (risk ratio [RR], 0.79 [95% CI, 0.66 to 0.93]; high-certainty evidence) and hemorrhagic stroke (RR, 0.48 [CI, 0.30 to 0.76]; moderate-certainty evidence). Compared with VKAs, the effects of NOACs on recurrent VTE or VTE-related death were uncertain (RR, 0.72 [CI, 0.44 to 1.17]; low-certainty evidence). In all trials combined, NOACs seemingly reduced major bleeding risk compared with VKAs (RR, 0.75 [CI, 0.56 to 1.01]; low-certainty evidence). Limitation: Scant evidence for advanced CKD or ESKD; data mostly from subgroups of large trials. Conclusion: In early-stage CKD, NOACs had a benefit–risk profile superior to that of VKAs. For advanced CKD or ESKD, there was insufficient evidence to establish benefits or harms of VKAs or NOACs. Primary Funding Source: None. (PROSPERO: CRD42017079709

Evidence for large-scale gene-by-smoking interaction effects on pulmonary function

Background: Smoking is the strongest environmental risk factor for reduced pulmonary function. The genetic component of various pulmonary traits has also been demonstrated, and at least 26 loci have been reproducibly associated with either FEV1 (forced expiratory volume in 1 second) or FEV1/FVC (FEV1/forced vital capacity). Although the main effects of smoking and genetic loci are well established, the question of potential gene-by-smoking interaction effect remains unanswered. The aim of the present study was to assess, using a genetic risk score approach, whether the effect of these 26 loci on pulmonary function is influenced by smoking. Methods: We evaluated the interaction between smoking exposure, considered as either ever vs never or pack-years, and a 26-single nucleotide polymorphisms (SNPs) genetic risk score in relation to FEV1 or FEV1/FVC in 50 047 participants of European ancestry from the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) and SpiroMeta consortia. Results: We identified an interaction (beta(int) = -0.036, 95% confidence interval, -0.040 to -0.032, P = 0.00057) between an unweighted 26 SNP genetic risk score and smoking status (ever/never) on the FEV1/FVC ratio. In interpreting this interaction, we showed that the genetic risk of falling below the FEV1/FVC threshold used to diagnose chronic obstructive pulmonary disease is higher among ever smokers than among never smokers. A replication analysis in two independent datasets, although not statistically significant, showed a similar trend in the interaction effect. Conclusions: This study highlights the benefit of using genetic risk scores for identifying interactions missed when studying individual SNPs and shows, for the first time, that persons with the highest genetic risk for low FEV1/FVC may be more susceptible to the deleterious effects of smoking.Peer reviewe

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

Ultrasound-guided needle localization during open parotid sialolithotomy

© 2014 American Academy of Otolaryngology - Head and Neck Surgery Foundation. Objectives. Our objective is to describe a novel operative technique for localization of parotid sialolithiasis, demonstrate the feasibility of the technique, and discuss its indications.Study Design. Prospective study.Setting. Tertiary-level academic center.Subjects and Methods. Patients with symptomatic parotid sialolithiasis who had failed prior sialendoscopic extraction underwent ultrasound needle localization and open sialolithotomy. Data were prospectively collected. Independent variables included size of and location of sialoliths.Results. Eleven patients were treated using transcutaneous ultrasound-guided needle placement and injection of methylene blue prior to external sialolithotomy. Follow-up ranged from 6 to 12 months. Ten (91.9%) patients had stones within the proximal one-third of the ductal lumen, and 1 (9.1%) had stones present within both the proximal one-third and middle one-third of the ductal lumen. The average surgical time was 53 ± 10.8 minutes. The average sialolith length was 7.6 ± 2 mm. The average sialolith width was 6 ± 1.9 mm. All 11 (100%) cases were successful for stone retrieval. Ten (91%) patients had complete symptom resolution, and 1 (9.1%) patient had partial resolution of symptoms. No patients had major complications. Three (27.3%) patients had minor complications.Conclusion. After failing a purely endoscopic approach, sialoliths of the parotid gland pose a problem for precise localization and treatment. Ultrasound has been demonstrated to be reliable for identifying sialoliths. We propose a novel technique and assert that ultrasound-guided needle localization is a reliable aid to effective external parotid sialolithotomy, especially for larger stones \u3e4 mm that are not amenable to sialendoscopic retrieval