A Calderon Regularized Symmetric Formulation for the Electroencephalography Forward Problem

The symmetric formulation of the electroencephalography (EEG) forward problem is a well-known and widespread equation thanks to the high level of accuracy that it delivers. However, this equation is first kind in nature and gives rise to ill-conditioned problems when the discretization density or the brain conductivity contrast increases, resulting in numerical instabilities and increasingly slow solutions. This work addresses and solves this problem by proposing a new regularized symmetric formulation. The new scheme is obtained by leveraging on Calderon identities which allow to introduce a dual symmetric equation that, combined with the standard one, results in a second kind operator which is both stable and well-conditioned under all the above mentioned conditions. The new formulation presented here can be easily integrated into existing EEG imaging packages since it can be obtained with the same computational technology required by the standard symmetric formulation. The performance of the new scheme is substantiated by both theoretical developments and numerical results which corroborate the theory and show the practical impact of the new technique

On a Calder\'on preconditioner for the symmetric formulation of the electroencephalography forward problem without barycentric refinements

We present a Calder\'on preconditioning scheme for the symmetric formulation of the forward electroencephalographic (EEG) problem that cures both the dense discretization and the high-contrast breakdown. Unlike existing Calder\'on schemes presented for the EEG problem, it is refinement-free, that is, the electrostatic integral operators are not discretized with basis functions defined on the barycentrically-refined dual mesh. In fact, in the preconditioner, we reuse the original system matrix thus reducing computational burden. Moreover, the proposed formulation gives rise to a symmetric, positive-definite system of linear equations, which allows the application of the conjugate gradient method, an iterative method that exhibits a smaller computational cost compared to other Krylov subspace methods applicable to non-symmetric problems. Numerical results corroborate the theoretical analysis and attest of the efficacy of the proposed preconditioning technique on both canonical and realistic scenarios

Migration Routes of New World Sanderlings (Calidris alba)

We color-marked Sanderlings (Calidris alba Pallas) at 19 locations in 6 countries in the New World and coordinated a network of volunteers to locate banded individuals in migration over a five-year period. The observers reported 252 independent sightings of birds in countries different from the country of banding. Sanderlings that migrate north to the Arctic from Chile and Peru travel principally through the central corridor (Texas and northward) of the United States and Canada; smaller numbers follow the Pacific coast. A few migrate north from the Pacific coast of South America along the Atlantic coast of the United States. Southbound from the Arctic to coastal Chile and Peru, many individuals switch eastward to stopovers on the Atlantic coast, including birds that migrated north along the U.S. Pacific coast. Sanderlings banded in Brazil during the nonbreeding period appear only on the U.S. Atlantic coast in migration. Our results emphasize the individual nature of migration. We found considerable heterogeneity in migratory behavior among individuals that spend the nonbreeding season together on the same beaches. Individuals from widely separated nonbreeding sites often shared similar pathways. In this species and perhaps in others, no simple single migratory route connects breeding with nonbreeding regions

Numerical Methods for the Stochastic Landau-Lifshitz Navier-Stokes Equations

The Landau-Lifshitz Navier-Stokes (LLNS) equations incorporate thermal fluctuations into macroscopic hydrodynamics by using stochastic fluxes. This paper examines explicit Eulerian discretizations of the full LLNS equations. Several CFD approaches are considered (including MacCormack's two-step Lax-Wendroff scheme and the Piecewise Parabolic Method) and are found to give good results (about 10% error) for the variances of momentum and energy fluctuations. However, neither of these schemes accurately reproduces the density fluctuations. We introduce a conservative centered scheme with a third-order Runge-Kutta temporal integrator that does accurately produce density fluctuations. A variety of numerical tests, including the random walk of a standing shock wave, are considered and results from the stochastic LLNS PDE solver are compared with theory, when available, and with molecular simulations using a Direct Simulation Monte Carlo (DSMC) algorithm

The Prevalence and Clinical Implications of Comorbid Back Pain in Shoulder Instability: A Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Instability Cohort Study.

Background:Understanding predictors of pain is critical, as recent literature shows that comorbid back pain is an independent risk factor for worse functional and patient-reported outcomes (PROs) as well as increased opioid dependence after total joint arthroplasty. Purpose/Hypothesis:The purpose of this study was to evaluate whether comorbid back pain would be predictive of pain or self-reported instability symptoms at the time of stabilization surgery. We hypothesized that comorbid back pain will correlate with increased pain at the time of surgery as well as with worse scores on shoulder-related PRO measures. Study Design:Cross-sectional study; Level of evidence, 3. Methods:As part of the Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Instability cohort, patients consented to participate in pre- and intraoperative data collection. Demographic characteristics, injury history, preoperative PRO scores, and radiologic and intraoperative findings were recorded for patients undergoing surgical shoulder stabilization. Patients were also asked, whether they had any back pain. Results:The study cohort consisted of 1001 patients (81% male; mean age, 24.1 years). Patients with comorbid back pain (158 patients; 15.8%) were significantly older (28.1 vs 23.4 years; P < .001) and were more likely to be female (25.3% vs 17.4%; P = .02) but did not differ in terms of either preoperative imaging or intraoperative findings. Patients with self-reported back pain had significantly worse preoperative pain and shoulder-related PRO scores (American Shoulder and Elbow Surgeons score, Western Ontario Shoulder Instability Index) (P < .001), more frequent depression (22.2% vs 8.3%; P < .001), poorer mental health status (worse scores for the RAND 36-Item Health Survey Mental Component Score, Iowa Quick Screen, and Personality Assessment Screener) (P < .01), and worse preoperative expectations (P < .01). Conclusion:Despite having similar physical findings, patients with comorbid back pain had more severe preoperative pain and self-reported symptoms of instability as well as more frequent depression and lower mental health scores. The combination of disproportionate shoulder pain, comorbid back pain and mental health conditions, and inferior preoperative expectations may affect not only the patient's preoperative state but also postoperative pain control and/or postoperative outcomes

Randomized clinical trial to evaluate the effect of fecal microbiota transplant for initial Clostridium difficile infection in intestinal microbiome

Objective The aim of this study was to evaluate the impact of fecal donor-unrelated donor mix (FMT-FURM) transplantation as first-line therapy for C. difficile infection (CDI) in intestinal microbiome. Methods We designed an open, two-arm pilot study with oral vancomycin (250mg every 6 h for 10–14 days) or FMT-FURM as treatments for the first CDI episode in hospitalized adult patients in Hospital Universitario “Dr. Jose Eleuterio Gonzalez”. Patients were randomized by a closed envelope method in a 1: 1 ratio to either oral vancomycin or FMT-FURM. CDI resolution was considered when there was a reduction on the Bristol scale of at least 2 points, a reduction of at least 50% in the number of bowel movements, absence of fever, and resolution of abdominal pain (at least two criteria). From each patient, a fecal sample was obtained at days 0, 3, and 7 after treatment. Specimens were cultured to isolate C. difficile, and isolates were characterized by PCR. Susceptibility testing of isolates was performed using the agar dilution method. Fecal samples and FMT-FURM were analyzed by 16S rRNA sequencing. Results We included 19 patients; 10 in the vancomycin arm and 9 in the FMT-FURM arm. However, one of the patients in the vancomycin arm and two patients in the FMT-FURM arm were eliminated. Symptoms resolved in 8/9 patients (88.9%) in the vancomycin group, while symptoms resolved in 4/7 patients (57.1%) after the first FMT-FURM dose (P = 0.26) and in 5/7 patients (71.4%) after the second dose (P = 0.55). During the study, no adverse effects attributable to FMT-FURM were observed in patients. Twelve isolates were recovered, most isolates carried tcdB, tcdA, cdtA, and cdtB, with an 18-bp deletion in tcdC. All isolates were resistant to ciprofloxacin and moxifloxacin but susceptible to metronidazole, linezolid, fidaxomicin, and tetracycline. In the FMT-FURM group, the bacterial composition was dominated by Firmicutes, Bacteroidetes, and Proteobacteria at all-time points and the microbiota were remarkably stable over time. The vancomycin group showed a very different pattern of the microbial composition when comparing to the FMT-FURM group over time. Conclusion The results of this preliminary study showed that FMT-FURM for initial CDI is associated with specific bacterial communities that do not resemble the donors’ sample.Peer reviewedFinal Published versio

Assessing the burden of paediatric influenza in Europe: the European Paediatric Influenza Analysis (EPIA) project

The European Paediatric Influenza Analysis (EPIA) project is a multi-country project that was created to collect, analyse and present data regarding the paediatric influenza burden in European countries, with the purpose of providing the necessary information to make evidence-based decisions regarding influenza immunisation recommendations for children. The initial approach taken is based on existing weekly virological and age-specific influenza-like illness (ILI) data from surveillance networks across Europe. We use a multiple regression model guided by longitudinal weekly patterns of influenza virus to attribute the weekly ILI consultation incidence pattern to each influenza (sub)type, while controlling for the effect of respiratory syncytial virus (RSV) epidemics. Modelling the ILI consultation incidence during 2002/2003–2008 revealed that influenza infections that presented for medical attention as ILI affected between 0.3% and 9.8% of children aged 0–4 and 5–14 years in England, Italy, The Netherlands and Spain in an average season. With the exception of Spain, these rates were always higher in children aged 0–4 years. Across the six seasons analysed (five seasons were analysed from the Italian data), the model attributed 47–83% of the ILI burden in primary care to influenza virus infection in the various countries, with the A(H3N2) virus playing the most important role, followed by influenza viruses B and A(H1N1). National season averages from the four countries studied indicated that between 0.4% and 18% of children consulted a physician for ILI, with the percentage depending on the country and health care system. Influenza virus infections explained the majority of paediatric ILI consultations in all countries. The next step will be to apply the EPIA modelling approach to severe outcomes indicators (i.e. hospitalisations and mortality data) to generate a complete range of mild and severe influenza burden estimates needed for decision making concerning paediatric influenza vaccination

Oxygen Activation and Radical Transformations in Heme Proteins and Metalloporphyrins

As a result of the adaptation of life to an aerobic environment, nature has evolved a panoply of metalloproteins for oxidative metabolism and protection against reactive oxygen species. Despite the diverse structures and functions of these proteins, they share common mechanistic grounds. An open-shell transition metal like iron or copper is employed to interact with O_2 and its derived intermediates such as hydrogen peroxide to afford a variety of metal–oxygen intermediates. These reactive intermediates, including metal-superoxo, -(hydro)peroxo, and high-valent metal–oxo species, are the basis for the various biological functions of O_2-utilizing metalloproteins. Collectively, these processes are called oxygen activation. Much of our understanding of the reactivity of these reactive intermediates has come from the study of heme-containing proteins and related metalloporphyrin compounds. These studies not only have deepened our understanding of various functions of heme proteins, such as O2 storage and transport, degradation of reactive oxygen species, redox signaling, and biological oxygenation, etc., but also have driven the development of bioinorganic chemistry and biomimetic catalysis. In this review, we survey the range of O_2 activation processes mediated by heme proteins and model compounds with a focus on recent progress in the characterization and reactivity of important iron–oxygen intermediates. Representative reactions initiated by these reactive intermediates as well as some context from prior decades will also be presented. We will discuss the fundamental mechanistic features of these transformations and delineate the underlying structural and electronic factors that contribute to the spectrum of reactivities that has been observed in nature as well as those that have been invented using these paradigms. Given the recent developments in biocatalysis for non-natural chemistries and the renaissance of radical chemistry in organic synthesis, we envision that new enzymatic and synthetic transformations will emerge based on the radical processes mediated by metalloproteins and their synthetic analogs

Policy Recommendations for Meeting the Grand Challenge to Achieve Equal Opportunity and Justice

This brief was created forSocial Innovation for America’s Renewal, a policy conference organized by the Center for Social Development in collaboration with the American Academy of Social Work & Social Welfare, which is leading theGrand Challenges for Social Work initiative to champion social progress. The conference site includes links to speeches, presentations, and a full list of the policy briefs