Dimensionality of social networks using motifs and eigenvalues

We consider the dimensionality of social networks, and develop experiments aimed at predicting that dimension. We find that a social network model with nodes and links sampled from an $m$-dimensional metric space with power-law distributed influence regions best fits samples from real-world networks when $m$ scales logarithmically with the number of nodes of the network. This supports a logarithmic dimension hypothesis, and we provide evidence with two different social networks, Facebook and LinkedIn. Further, we employ two different methods for confirming the hypothesis: the first uses the distribution of motif counts, and the second exploits the eigenvalue distribution.Comment: 26 page

Perioperative Cardiac Arrests

Perioperative cardiac arrests represent the most serious complication of anesthesia and surgery. It is believed that the incidence and mortality of cardiac arrest has declined, however, a more recent review questioned whether these rates have changed over the last 5 decades. It is difficult to compare the reports from different epochs, because medical practice has advanced, surgical acuity increased, and patients in extremes of age undergo surgery today. In the present article we review the information regarding the incidence of perioperative cardiac arrests and predictors of survival covering the period since the first comprehensive report by Beecher and Todd in 1954. We focus on our publications that report perioperative cardiac arrest at Mayo Clinic for adult noncardiac surgery, during regional anesthesia, and arrests in our pediatric surgical practice

Pediatric surgical extracorporeal membrane oxygenation - a case series

Objective. To review demographic and procedural factors and their association with weaning rate and survival from extracorporeal membrane oxygenation (ECMO) in pediatric patients undergoing repair of cardiac malformations. Methods. The hospital records of children requiring ECMO during cardiac operation due to failure to wean from cardio-pulmonary by pass (CPB) were retrospectively reviewed, and an analysis of variables affecting survival was performed. Results. Thirty-five pediatric patients between January 1, 2000 and December 31, 2006 required ECMO for cardiopulmonary support during cardiac operations. ECMO survival was 54.3% and was comparable across all age groups. The lowest pH during ECMO treatment was the only predictor of mortality (P = 0.006). No other patient, surgical or anesthetic, factor was associated with either weaning from ECMO or hospital survival. Conclusions. No clear risk factor could be identified for survival from ECMO in our pediatric patients who underwent cardiac surgery and failed weaning from cardiopulmonary bypass

Evaluation of clinical benefit from treatment with mepolizumab for patients with eosinophilic granulomatosis with polyangiitis.

BACKGROUND: In a recent phase III trial (NCT02020889) 53% of mepolizumab-treated versus 19% of placebo-treated patients with eosinophilic granulomatosis with polyangiitis (EGPA) achieved protocol-defined remission. OBJECTIVE: We sought to investigate post hoc the clinical benefit of mepolizumab in patients with EGPA using a comprehensive definition of benefit encompassing remission, oral glucocorticoid (OGC) dose reduction, and EGPA relapses. METHODS: The randomized, placebo-controlled, double-blind, parallel-group trial recruited patients with relapsing/refractory EGPA receiving stable OGCs (prednisolone/prednisone, ≥7.5-50 mg/d) for 4 or more weeks. Patients received 300 mg of subcutaneous mepolizumab or placebo every 4 weeks for 52 weeks. Clinical benefit was defined post hoc as follows: remission at any time (2 definitions used), 50% or greater OGC dose reduction during weeks 48 to 52, or no EGPA relapses. The 2 remission definitions were Birmingham Vasculitis Activity Score of 0 plus OGC dose of 4 mg/d or less (remission 1/clinical benefit 1) or 7.5 mg/d or less (remission 2/clinical benefit 2). Clinical benefit was assessed in all patients and among subgroups with a baseline blood eosinophil count of less than 150 cells/μL, baseline OGC dosage of greater than 20 mg/d, or weight of greater than 85 kg. RESULTS: With mepolizumab versus placebo, 78% versus 32% of patients experienced clinical benefit 1, and 87% versus 53% of patients experienced clinical benefit 2 (both P < .001). Significantly more patients experienced clinical benefit 1 with mepolizumab versus placebo in the blood eosinophil count less than 150 cells/μL subgroup (72% vs 43%, P = .033) and weight greater than 85 kg subgroup (68% vs 23%, P = .005); in the OGC greater than 20 mg/d subgroup, results were not significant but favored mepolizumab (60% vs 36%, P = .395). CONCLUSION: When a comprehensive definition of clinical benefit was applied to data from a randomized controlled trial, 78% to 87% of patients with EGPA experienced benefit with mepolizumab

Dopamine and Glutamate in Antipsychotic-Responsive Compared With Antipsychotic-Nonresponsive Psychosis: A Multicenter Positron Emission Tomography and Magnetic Resonance Spectroscopy Study (STRATA)

The variability in the response to antipsychotic medication in schizophrenia may reflect between-patient differences in neurobiology. Recent cross-sectional neuroimaging studies suggest that a poorer therapeutic response is associated with relatively normal striatal dopamine synthesis capacity but elevated anterior cingulate cortex (ACC) glutamate levels. We sought to test whether these measures can differentiate patients with psychosis who are antipsychotic responsive from those who are antipsychotic nonresponsive in a multicenter cross-sectional study. 1H-magnetic resonance spectroscopy (1H-MRS) was used to measure glutamate levels (Glucorr) in the ACC and in the right striatum in 92 patients across 4 sites (48 responders [R] and 44 nonresponders [NR]). In 54 patients at 2 sites (25 R and 29 NR), we additionally acquired 3,4-dihydroxy-6-[18F]fluoro-L-phenylalanine (18F-DOPA) positron emission tomography (PET) to index striatal dopamine function (Kicer, min−1). The mean ACC Glucorr was higher in the NR than the R group after adjustment for age and sex (F1,80 = 4.27; P = .04). This was associated with an area under the curve for the group discrimination of 0.59. There were no group differences in striatal dopamine function or striatal Glucorr. The results provide partial further support for a role of ACC glutamate, but not striatal dopamine synthesis, in determining the nature of the response to antipsychotic medication. The low discriminative accuracy might be improved in groups with greater clinical separation or increased in future studies that focus on the antipsychotic response at an earlier stage of the disorder and integrate other candidate predictive biomarkers. Greater harmonization of multicenter PET and 1H-MRS may also improve sensitivity

One-Year Prevalence Rates of Major Depressive Disorder in First-Year University Students

First-year university students may be more at risk for experiencing Major Depressive Disorder (MDD) than the general population given associated risk factors of this age range. A two-phase procedure was used to estimate the one-year prevalence rate of MDD and comorbid Major Anxiety Disorders among first-year university students at a small Canadian university. The results of the study indicate that approximately 7% of men and 14% of women in their first year met the criteria for MDD. Further, about 13% of men and 19% of women met the criteria for a Major Anxiety Disorder. Implications of these findings are discussed.Les étudiants de première année d’université peuvent être plus exposés au risque d’éprouver un trouble dépressif majeur (TDM) que l’ensemble de la population, étant donné les facteurs de risque liés à ce groupe d’âge. Une procédure en deux étapes a été utilisée pour estimer le taux de prévalence du TDM et des troubles majeurs de l’anxiété dans une petite université canadienne. Les résultats de l’étude indiquent que 7 % environ des hommes et 14 % environ des femmes en première année satisfont aux critères de TDM. En outre, environ 13 % des hommes et 19 % des femmes satistaisaient aux critères d’un trouble majeur de l’anxiété. Les répercussions de ces résultats sont discutés

The scale of the network data involved in our study varies over three orders of magnitude.

<p>We see similar scaling for both types of networks, but with slightly different offsets. For Facebook, with ; for LinkedIn with . The regularity in the LinkedIn sizes is due to our construction of those networks.</p