University of California

About: University of California is a education organization based out in Oakland, California, United States. It is known for research contribution in the topics: Population & Layer (electronics). The organization has 55175 authors who have published 52933 publications receiving 1491169 citations. The organization is also known as: UC & University of California System.

Mutual interactions, potentials, and individual distance in a social aggregation

Abstract: We formulate a Lagrangian (individual-based) model to investigate the spacing of individuals in a social aggregate (e.g., swarm, flock, school, or herd). Mutual interactions of swarm members have been expressed as the gradient of a potential function in previous theoretical studies. In this specific case, one can construct a Lyapunov function, whose minima correspond to stable stationary states of the system. The range of repulsion (r) and attraction (a) must satisfy r cAa(d+1) where R, A are magnitudes, c is a constant of order 1, and d is the space dimension) to avoid collapse of the group to a tight cluster. We also verify the existence of a well-spaced locally stable state, having a characteristic individual distance. When the number of individuals in a group increases, a dichotomy occurs between swarms in which individual distance is preserved versus those in which the physical size of the group is maintained at the expense of greater crowding.

Perfusion balloon catheter

Abstract: A balloon catheter utilizing a perfusion balloon at one end thereof is described. The perfusion balloon has a donut shaped cross section having a central opening formed therethrough. The central opening provides a blood flow passage even when the balloon is fully inflated. When inflated, the perfusion balloon is used to dilate a stenotic region of a blood vessel or heart valve to restore blood flow. After deflation, if the blood vessel collapses, the balloon catheter of the present invention can be reinflated and kept in place while the patient is prepared for surgery. In this manner, acceptable blood flow is provided regardless of the length of time required for surgical preparation. In an alternate embodiment, a one-way valve is formed integrally with the perfusion balloon so that the present invention may be better applied to valvuloplasty. In this application, the balloon is inflated at a stenotic region of a heart valve to expand the valve and restore acceptable blood flow. The one-way valve of the perfusion balloon takes the place of the coronary valve so that normal operation of the heart can be maintained during the valvuloplasty process.

Designing Research Studies on Psychosocial Interventions in Autism

Abstract: To address methodological challenges in research on psychosocial interventions for autism spectrum disorder (ASD), a model was developed for systematically validating and disseminating interventions in a sequence of steps. First, initial efficacy studies are conducted to establish interventions as promising. Next, promising interventions are assembled into a manual, which undergoes pilot-testing. Then, randomized clinical trials test efficacy under controlled conditions. Finally, effectiveness studies evaluate outcomes in community settings. Guidelines for research designs at each step are presented. Based on the model, current priorities in ASD research include (a) preparation for efficacy and effectiveness trials by developing manuals for interventions that have shown promise and (b) initial efficacy studies on interventions for core features of ASD such as social reciprocity.

Asymmetric electrophilic fluorination using an anionic chiral phase-transfer catalyst

Abstract: The discovery of distinct modes of asymmetric catalysis has the potential to rapidly advance chemists' ability to build enantioenriched molecules. As an example, the use of chiral cation salts as phase-transfer catalysts for anionic reagents has enabled a vast set of enantioselective transformations. A largely overlooked analogous mechanism wherein a chiral anionic catalyst brings a cationic species into solution is itself a powerful method. The concept is broadly applicable to a number of different reaction pathways, including to the enantioselective fluorocyclization of olefins, and dearomatization of aromatic systems with a cationic electrophile-transferring (e.g., fluorinating) agent and a chiral phosphate catalyst. The reactions proceed in high yield and stereoselectivity. The compounds and methods of the invention are of particular value, especially considering the scarcity of alternative approaches.

Processing speed deficits in attention deficit/hyperactivity disorder and reading disability.

Abstract: The goal of the current study was to test whether deficits in processing speed (PS) may be a shared cognitive risk factor in reading disability (RD) and Attention Deficit/Hyperactivity Disorder (ADHD), which are known to be comorbid. Literature on ADHD and RD suggests that deficits on tasks with a speeded component are seen in both of these disorders individually. The current study examined a wide range of speeded tasks in RD, ADHD, comorbid RD+ADHD, and a control group to test whether RD and ADHD have similar profiles of PS deficits, and whether these deficits are shared by the two disorders. The results suggest that a general PS deficit exists in both clinical groups compared to controls, although children with RD demonstrate greater PS deficits than children with ADHD. Two tests (underadditivity and partial correlations) were conducted to test whether these PS deficits are shared. Since we found that PS deficits were underadditive in the comorbid group and that partialling PS reduced the correlation between RD and ADHD, it appears that PS is a shared cognitive risk factor that may help explain the comorbidity of these two disorders.