Theoretical and material studies on thin-film electroluminescent devices

A theoretical study of resonant tunneling in multilayered heterostructures is presented based on an exact solution of the Schroedinger equation under the application of a constant electric field. By use of the transfer matrix approach, the transmissivity of the structure is determined as a function of the incident electron energy. The approach presented is easily extended to many layer structures where it is more accurate than other existing transfer matrix or WKB models. The transmission resonances are compared to the bound state energies calculated for a finite square well under bias using either an asymmetric square well model or the exact solution of an infinite square well under the application of an electric field. The results show good agreement with other existing models as well as with the bound state energies. The calculations were then applied to a new superlattice structure, the variablly spaced superlattice energy filter, (VSSEP) which is designed such that under bias the spatial quantization levels fully align. Based on these calculations, a new class of resonant tunneling superlattice devices can be designed

Theoretical and material studies on thin-film electroluminescent devices

During this report period work was performed on the modeling of High Field Electronic Transport in Bulk ZnS and ZnSe, and also on the surface cleaning of Si for MBE growth. Some MBE growth runs have also been performed in the Varian GEN II System. A brief outline of the experimental work is given. A complete summary will be done at the end of the next reporting period at the completion of the investigation. The theoretical studies are included

Genetic mouse models of migraine

Mouse models of rare monogenic forms of migraine provide a unique experimental system to study the cellular and circuit mechanisms of the primary brain dysfunctions causing a migraine disorder. Here, we discuss the migraine-relevant phenotypes and the migraine-relevant functional alterations in the brain of five genetic mouse models of migraine, four of which carry mutations derived from patients with familial hemiplegic migraine (FHM) and the fifth carry a mutation from patients with both phenotypically normal MA and familial advanced sleep phase syndrome (FASPS). We focus on the latter mouse model, in which a ubiquitous serine-threonine kinase is mutated, and on two mouse models of pure FHM, in which a voltage-gated calcium channel controlling neurotransmitter release at most brain synapses and a Na/K ATPase that is expressed mainly in astrocytes in the adult brain are mutated, respectively. First, we describe the behavioral phenotypes of the genetic animal models and review the evidence that an increased susceptibility to experimentally induced cortical spreading depression (CSD) is a key migraine-relevant phenotype common to the five models. Second, we review the synaptic alterations in the cerebral cortex of the genetic models of migraine and discuss the mechanisms underlying their increased susceptibility to CSD. Third, we review the alterations in the trigeminovascular pain pathway and discuss possible implications for migraine pain mechanisms. Finally, we discuss the insights into migraine pathophysiology obtained from the genetic models of migraine, in particular regarding the mechanisms that make the brain of migraineurs susceptible to the ignition of "spontaneous" CSDs. Although the reviewed functional studies support the view of migraine as a disorder of the brain characterized by dysfunctional regulation of the excitatory/inhibitory balance in specific neuronal circuits, much work remains to be done in the genetic mouse models e.g. to identfy the relevant dysfunctional circuits and to establish whether and how the alterations in the function of specific circuits (in the cerebral cortex and/or other brain areas) are state-dependent and may, in certain conditions, favor CSD ignition and the migraine attack

A Systems Neuroscience Approach to Migraine

Migraine is an extremely common but poorly understood nervous system disorder. We conceptualize migraine as a disorder of sensory network gain and plasticity, and we propose that this framing makes it amenable to the tools of current systems neuroscience

Evaluating air traffic flow management in a collaborative decision-making environment

The collaborative decision-making (CDM) framework introduced into ground delay programs in the late 1990s is an integral component of FAA's traffic flow management (TFM) procedures. CDM allows FAA to act as a mediator when managing TFM programs, transferring as much decision making as possible to the individual airlines. Although this approach has been highly successful in practice, it creates a new question for the research community: How should proposed enhancements to TFM be evaluated in a CDM environment? A sequential evaluation procedure, developed in this paper, addresses this question. The procedure includes airline disruption responses and a quasi-compression operation, attempting to mimic the three-stage CDM process. To model airline disruption responses, an integer optimization model was developed to balance operational and passenger considerations in determining which flights to cancel, swap, or delay. The value of this procedure is demonstrated by analyzing an optimization-based TFM approach in the CDM environment

Protocol for a national monthly survey of alcohol use in England with 6-month follow-up: 'The Alcohol Toolkit Study'.

Timely tracking of national patterns of alcohol consumption is needed to inform and evaluate strategies and policies aimed at reducing alcohol-related harm. Between 2014 until at least 2017, the Alcohol Toolkit Study (ATS) will provide such tracking data and link these with policy changes and campaigns. By virtue of its connection with the 'Smoking Toolkit Study' (STS), links will also be examined between alcohol and smoking-related behaviour

Initiating Patient Discussions about Oocyte Cryopreservation: Attitudes of Obstetrics and Gynaecology Resident Physicians

This study examined the attitudes of obstetrics and gynaecology (OB/GYN) resident physicians to initiating patient discussions regarding medical and elective oocyte cryopreservation (OC). The study used a cross-sectional online survey of OB/GYN medical residents in the USA, sampled from residency programmes approved by the American Council for Graduate Medical Education. In total, 208 medical residents, distributed evenly between postgraduate years 1–4, participated in the study. Residents\u27 fertility knowledge and attitudes to initiating discussions about OC were gathered. Forty percent (n = 83) believed that OB/GYN residents should initiate discussions about OC with patients (initiators), while 60% (n = 125) did not (non-initiators). Initiators were less likely to overestimate the age at which a woman\u27s fertility begins to decline, and were more likely to believe that discussions about OC and age-related fertility decline should take place during a well-woman annual examination. Initiators and non-initiators did not differ in their attitudes towards discussing OC with patients undergoing cancer treatments; however, initiators were significantly more likely to discuss elective OC with patients who were currently unpartnered or who wished to delay childbearing to pursue a career. Given the increasing age of childbearing among women, and the fact that women prefer to receive reproductive information from their healthcare providers, it is critical that such topics are discussed in consultations to assist patients in making more informed reproductive decisions. Further research is needed to assess the existing barriers to these discussions from both physician and patient perspectives

An Integrated Circuit for Signal Processing of the AMS RICH Photmultipliers Tubes

An analog integrated circuit has been designed, in a BiCMOS 0.8 micron technology, for the feasability study of the signal processing of the AMS RICH photomultiplier tubes. This low power, three channel gated integrator includes its own gate and no external analog delay is requiered. It processes PMT pulses over a dynamic range of more than 100. A logic output that indicates whether the analog charge has to be considered is provided. This gated integrator is used with a compact DSP based acquisition system in a 132 channels RICH prototype. The charge calibration of each channel is carried out using a LED. The pedestal measurement is performed on activation of a dedicated input. The noise contribution study of the input RC network and amplifiers is presented.Comment: IEEE symp. on Nucl. Sci. and Med. Imaging, Toront