Detecting gravity waves from binary black holes

One of the most attractive possible sources of strong gravitational waves would be a binary system comprising massive black holes (BH). The gravitational radiation from a binary is an elliptically polarized, periodic wave which could be observed continuously - or at intervals whenever a detector was available. This continuity of the signal is certainly appealing compared to waiting for individual pulses from infrequent random events. It also has the advantage over pulses that continued observation can increase the signal-to-noise ratio almost indefinitely. Furthermore, this system is dynamically simple; the theory of the generation of the radiation is unambiguous; all characteristics of the signal can be precisely related to the dynamical parameters of the source. The current situation is that while there is no observational evidence as yet for the existence of massive binary BH, their formation is theoretically plausible, and within certain coupled constraints of mass and location, their existence cannot be observationally excluded. Detecting gravitational waves from these objects might be the first observational proof of their existence

Shaped superconductor cylinder retains intense magnetic field

The curve of the inner walls of a superconducting cylinder is plotted from the flux lines of the magnetic field to be contained. This shaping reduces maximum flux densities and permits a stronger and more uniform magnetic field

A Review of the Role of Anxiety in Diagnosis of Children and Adolescents with Autism Spectrum Disorder: A Paradigm Shift in Conceptualization and Diagnosis

Early evidence of co-occurring anxiety symptoms in children and adolescents with autism spectrum disorder (ASD) dates back to the first descriptions of ASD by Leo Kanner (1943) and Hans Asperger (Frith & Mira, 1992). While current research has identified anxiety disorders as one of the most prevalent co-occurring disorders in children and adolescents with ASD, little is known about the nature of the relationship between these disorders. In an effort to explain these high prevalence rates, recent research has started to investigate the relationship between these two disorders. To join these efforts, this clinical research project explored the role of anxiety in diagnosis of children and adolescents with ASD. To guide the exploration of this role, the following research questions were answered: How prevalent or significant is anxiety in children and adolescents with ASD?; How do symptoms of anxiety manifest in children and adolescents with ASD?; and How is anxiety conceptualized, assessed, and treated in ASD? Results from this literature review indicate that there are current limitations in this area of research that need to be addressed to form an accurate conceptualization of anxiety symptoms in this population. Steps to resolve these limitations are discussed and areas of further research are explored. Recommendations for accurately assessing and treating co-occurring symptoms of anxiety in youth with ASD are provided and a suggested conceptualization model based off current research is proposed

Rigid motions in Einstein spaces

Rigid motion in Einstein space-time using dyadic formulation of general relativit

Lie algebra computations

In the context of prolongation theory, introduced by Wahlquist and Estabrook, computations of a lot of Jacobi identities in (infinite-dimensional) Lie algebras are necessary. These computations can be done (automatically) using ‘symbolic computations’. A package written in REDUCE is demonstrated to give an idea of the chosen approach

Studies in hard pion photoproduction

The production of high transverse momenta mesons via polarized photoproduction can be a means of determining the parton structure of the target. at the regions of highest transverse pion momenta, kT, it can be shown that short distance, direct, pion production dominates and is sensitive to the polarized quark distributions. as the produced pions transverse momenta decreases the importance of pions produced through fragmentation following photon-gluon fusion increases. This process give us sensitivity to the form of the polarized gluon distribution. Both processes are calculable with perturbative Quantum Chromodynamics (pQCD) due to the high kT of the pion produced. Numerical results are presented for conditions in current g1 experiments. In order to determine the region in which the kT is sufficient for the use of pQCD, and to separate the desired processes from unwanted background functions, a calculation of the soft processes is undertaken. Vector meson dominance is the largest contributor to the soft processes and can be large enough to make a measurement of the asymmetries susceptible to the polarized gluon distributions difficult at the kinematics of existing g1 experiments. Once all of the contributions are known I can use the above processes to extend Bloom-Giliman scaling and duality to semi-exclusive processes. It will be shown that the scaling behavior should exist for the direct process and that regions where this process is dominant do exist. I will also show that the constancy with changing momentum transfer of the resonance peak/scaling curve ratio, familiar for many resonances in deep inelastic scattering, is also expected in the semi-exclusive case

Actively controlled cardiac afterload

Ex vivo (outside of the body) working heart models enable the evaluation of isolated hearts. They are envisioned to play an important role in increasing the currently low utilization rate of donor hearts for transplantation. For the heart to work in isolation, an afterload (flow impedance) is needed. To date, afterload devices have been constructed by combining multiple constituent elements such as pumps, flow resistances, and flow capacitances (compliances), typically to replicate the structure of so-called Windkessel models. This limits active control to that achievable by varying these elements, making it slow and subject to the problem of dynamic coupling between parameters. Here we present a novel concept to achieve Windkessel dynamics through a very simple variable flow impedance. The impedance is actively controlled using feedback from a pressure measurement. Through simulations we demonstrate the ability to perfectly emulate Windkessel dynamics, while imposing tight pressure limits needed for safe operation—something not achievable with the verbatim implementation using constituent elements