Quantifying brain development in the HEALthy Brain and Child Development (HBCD) Study: The magnetic resonance imaging and spectroscopy protocol.

The HEALthy Brain and Child Development (HBCD) Study, a multi-site prospective longitudinal cohort study, will examine human brain, cognitive, behavioral, social, and emotional development beginning prenatally and planned through early childhood. The acquisition of multimodal magnetic resonance-based brain development data is central to the study's core protocol. However, application of Magnetic Resonance Imaging (MRI) methods in this population is complicated by technical challenges and difficulties of imaging in early life. Overcoming these challenges requires an innovative and harmonized approach, combining age-appropriate acquisition protocols together with specialized pediatric neuroimaging strategies. The HBCD MRI Working Group aimed to establish a core acquisition protocol for all 27 HBCD Study recruitment sites to measure brain structure, function, microstructure, and metabolites. Acquisition parameters of individual modalities have been matched across MRI scanner platforms for harmonized acquisitions and state-of-the-art technologies are employed to enable faster and motion-robust imaging. Here, we provide an overview of the HBCD MRI protocol, including decisions of individual modalities and preliminary data. The result will be an unparalleled resource for examining early neurodevelopment which enables the larger scientific community to assess normative trajectories from birth through childhood and to examine the genetic, biological, and environmental factors that help shape the developing brain

Comparing MRI metrics to quantify white matter microstructural damage in multiple sclerosis

Quantifying white matter damage in vivo is becoming increasingly important for investigating the effects of neuroprotective and repair strategies in multiple sclerosis (MS). While various approaches are available, the relationship between MRI‐based metrics of white matter microstructure in the disease, that is, to what extent the metrics provide complementary versus redundant information, remains largely unexplored. We obtained four microstructural metrics from 123 MS patients: fractional anisotropy (FA), radial diffusivity (RD), myelin water fraction (MWF), and magnetisation transfer ratio (MTR). Coregistration of maps of these four indices allowed quantification of microstructural damage through voxel‐wise damage scores relative to healthy tissue, as assessed in a group of 27 controls. We considered three white matter tissue‐states, which were expected to vary in microstructural damage: normal appearing white matter (NAWM), T2‐weighted hyperintense lesional tissue without T1‐weighted hypointensity (T2L), and T1‐weighted hypointense lesional tissue with corresponding T2‐weighted hyperintensity (T1L). All MRI indices suggested significant damage in all three tissue‐states, the greatest damage being in T1L. The correlations between indices ranged from r = 0.18 to r = 0.87. MWF was most sensitive when differentiating T2L from NAWM, while MTR was most sensitive when differentiating T1L from NAWM and from T2L. Combining the four metrics into one, through a principal component analysis, did not yield a measure more sensitive to damage than any single measure. Our findings suggest that the metrics are (at least partially) correlated with each other, but sensitive to the different aspects of pathology. Leveraging these differences could be beneficial in clinical trials testing the effects of therapeutic interventions

A Survey of Experimental Research on Contests, All-Pay Auctions and Tournaments

Many economic, political and social environments can be described as contests in which agents exert costly efforts while competing over the distribution of a scarce resource. These environments have been studied using Tullock contests, all-pay auctions and rankorder tournaments. This survey provides a review of experimental research on these three canonical contests. First, we review studies investigating the basic structure of contests, including the contest success function, number of players and prizes, spillovers and externalities, heterogeneity, and incomplete information. Second, we discuss dynamic contests and multi-battle contests. Then we review research on sabotage, feedback, bias, collusion, alliances, and contests between groups, as well as real-effort and field experiments. Finally, we discuss applications of contests to the study of legal systems, political competition, war, conflict avoidance, sales, and charities, and suggest directions for future research. (author's abstract

A BIOMECHANICAL MODEL FOR THE GRAVID UTERUS

A biomechanical model for the gravid uterus B. Irfanoglu & E. Karaesmen Department of Engineering Sciences, Middle East Technical University, 06531 Ankara, Turkey ABSTRACT The biomechanics of the uterus is studied on a mathematical model based on a shell of ellipsoid of revolution. The myometrium is treated as a homogenous, isotropic and incompressible elastic material using continuum approach and large deformation theory as introduced by Fliigge and Chou [1] and Green and Adkins [2]. The governing equations which are nonlinear differential equations of boundary value type are solved by the shooting method together with the Runge-Kutta integration scheme. The numerical results showing the variation of stretch ratios with uterine pressure are presented graphically for neo-Hookean and Mooney-Rivlin type of materials. INTRODUCTION The importance of mechanical parameters in uterine activity has been well recognized but, unfortunately, manifested only in relatively smal

Optimal Gabor Kernel Location Selection For Face Recognition

In local feature--based face recognition systems, the topographical locations of feature extractors directly affect the discriminative power of a recognizer. Better recognition accuracy can be achieved by the determination of the positions of salient image locations. Most of the facial feature selection algorithms in the literature work with two assumptions: one, that the importance of each feature is independent of the other features, and two, that the kernels should be located at fiducial points. Under these assumption, one can only get a sub--optimal solution. In this paper, we present a methodology that tries to overcome this problem by relaxing the two assumptions using a formalism of subset selection problem. We use a number of feature selection algorithms and a genetic algorithm. Comparative results on the FERET dataset confirm the viability of our approach

Numerical simulation of groundwater contamination

In this study, the finite difference modeling technique is used to develop a simulation program that can be used for groundwater contamination problems. The simulation program is written in C++ programming language and runs on personal computers using Windows 95. The simulation program supplies an interactive user interface containing useful tools for pre-processing and postprocessing the data. Numerical models are capable of simulating two-dimensional areal aquifer systems with various conditions. Finite difference equations are derived by using vector volumes. Groundwater flow equations and advective-dispersive contaminant transport equations are solved in an uncoupled method. The iterative alternating direction implicit method is used with the Gauss elimination method to obtain solutions. Solution codes for the flow equation are implemented from previous researchers ' studies in this field. Variable grid generation is added to the implemented codes. The program is capable of displaying head and concentration distributions and velocity fields on the discretized aquifer domain. It is supplied with various output file options for the solutions

THE MANAGEMENT OF THYROTOXICOSIS BY THERAPEUTIC PLASMA EXCHANGE IN PATIENTS COMPLICATED WITH ANTITHYROID DRUGS

Objective. Antithyroid drugs, surgical excision, and radiation therapy with I-131 are the common treatment modalities thyrotoxicosis. The medical treatment of thyrotoxicosis has approximately 0.35% serious complications which consist of agranulocytosis, liver necrosis and failure. Therapeutic plasma exchange is an effective preoperative preparation method in thyrotoxicosis patients who are candidates for surgery and unable to manage an euthyroid state with medical treatment. Patients and Methods. This study was constructed between 2002-2009 in 9 patients who were resistant or had complications with medical treatment of thyrotoxicosis. The therapeutic plasma exchange procedures were performed with discontinuous flow cell separator devices. Results. Seven patients were females and 2 patients were males. The mean age was 51.22 years (32-78 years). The mean duration of the disease was 35.4 months (3-120 months). The patients underwent 3.3 (2-6 sessions) session of therapeutic plasma exchange before surgery. The mean volume of plasma exchange was 10549 mL (7150-18372 mL). The plasma is exchanged with %10 albumin and/or fresh frozen plasma. The complication rate was 22% during therapeutic plasma exchange. Four patients underwent near total thyroidectomy and five patients underwent total thyroidectomy. The mortality rate was zero. Neck hematoma causing acute respiratory compromise and requiring urgent evacuation developed in one patient. Conclusions. Total plasma exchange is an effective and safe procedure in preoperative preparation of the patients with thyrotoxicosis who were resistant or complicated with antithyroid drug in which a high level of concern and steady supervision is mandatory to prevent life threatening preoperative and postoperative complications