Dynamics of rapidly rotating Bose-Einstein condensates in a harmonic plus quartic trap

A two-dimensional rapidly rotating Bose-Einstein condensate in a harmonic plus quartic trap is expected to have unusual vortex states that do not occur in a pure harmonic trap. At a critical rotation speed $\Omega_h$, a central hole appears in the condensate, and at some faster rotation speed $\Omega_g$, the system undergoes a transition to a giant vortex state with pure irrotational flow. Using a time-dependent variational analysis, we study the behavior of an annular condensate with a single concentric ring of vortices. The transition to a giant vortex state is investigated by comparing the energy of the two equilibrium states (the ring of vortices and the giant vortex) and also by studying the dynamical stability of small excitation modes of the ring of vortices.Comment: 12pages, 4figure

Instrumentation for the Study of Animal Responses to Ultrasonic Sound

In cooperation with the United States Department of Agriculture, Agricultural Research Service, the Electrical Engineering Department at South Dakota State University is testing the effects of ultrasound on coyotes. It is known that coyotes can hear high pitched tones of higher frequency than that of the human ear. The overall goal of this research is to investigate the feasibility of using ultrasound to repel predators, mainly the coyote, from livestock. It has also been found from preliminary experiments that there is a significant increase in the heart rate of the coyote during exposure to noise levels of 100 to 110 dB. The purpose of this thesis is to develop instrumentation for this research. In order for the reader to understand the purpose of instrumentation which will be discussed in the following chapters, the experiments which are to be conducted will be described in the following paragraphs. The experiment is divided into two phases. The object of phase one is to find the sound which is most annoying to the coyote. Coyotes are exposed to various sounds seen as frequency modulated sound and interrupted sound, with the frequency between 16 and 40 KHz. Whether the coyote is annoyed or not is determined by observing the heart rate and the coyotes physical reactions by means of a video tape recorder. An EKG (electrocardiogram) transmitter is mounted on the chest of the coyote. From the results of phase one, the most annoying sound will be determined. Phase two is based on an avoidance technique used in psychological experiments. A 4 by 12 foot pen is divided by a hurdle into two compartments. Ultrasonic transducers are mounted in both compartments. The most annoying sound is then switched on and off in either side randomly and alternatively. The important observation will be whether the coyote is avoiding the sound or not; i.e. if the sound is presented in one compartment, we expect the coyote to move to the other

Fluctuation-enhanced sensing

We present a short survey on fluctuation-enhanced gas sensing. We compare some of its main characteristics with those of classical sensing. We address the problem of linear response, information channel capacity, missed alarms and false alarms.Comment: Keynote Talk at SPIE's 4th international symposium on Fluctuations and Noise, Conference Noise and Fluctuations in Circuits, Devices and Materials, Florence, Italy, May 20-24, 200

A proposal for a scalable universal bosonic simulator using individually trapped ions

We describe a possible architecture to implement a universal bosonic simulator (UBS) using trapped ions. Single ions are confined in individual traps, and their motional states represent the bosonic modes. Single-mode linear operators, nonlinear phase-shifts, and linear beam splitters can be realized by precisely controlling the trapping potentials. All the processes in a bosonic simulation, except the initialization and the readout, can be conducted beyond the Lamb-Dicke regime. Aspects of our proposal can also be applied to split adiabatically a pair of ions in a single trap

Sensitivity-based scaling for correlating structural response from different analytical models

A sensitivity-based linearly varying scale factor is described used to reconcile results from refined models for analysis of the same structure. The improved accuracy of the linear scale factor compared to a constant scale factor as well as the commonly used tangent approximation is demonstrated. A wing box structure is used as an example, with displacements, stresses, and frequencies correlated. The linear scale factor could permit the use of a simplified model in an optimization procedure during preliminary design to approximate the response given by a refined model over a considerable range of design changes

Antiepileptic drugs for the primary and secondary prevention of seizures after stroke

BACKGROUND: This is an updated version of the original Cochrane review published in 2010, Issue 1. Seizures after stroke are an important clinical problem, and they may be associated with poor outcome. The effects of antiepileptic drugs for the primary and secondary prevention of seizures after stroke remain unclear. OBJECTIVES: We aimed to assess the effects of antiepileptic drugs for the primary and secondary prevention of seizures after stroke. SEARCH METHODS: We searched the Specialised Registers of the Cochrane Epilepsy Group (12 August 2013) and the Cochrane Stroke Group (12 August 2013), the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library 2013, Issue 7), and MEDLINE (OVID, 1946 to 12 August 2013). We also checked the reference lists of articles retrieved from these searches. SELECTION CRITERIA: Randomised and quasi-randomised controlled trials in which participants were assigned to treatment or control group (placebo or no drug). DATA COLLECTION AND ANALYSIS: Two review authors independently screened all the titles, abstracts, and keywords of publications identified by the searches to assess their eligibility, and both review authors assessed their suitability for inclusion according to prespecified selection criteria. We included only one study for data collection and analysis. MAIN RESULTS: We found only one trial that fulfilled the study inclusion criteria of comparison of the effects of an antiepileptic drug with placebo (or no drug) for the primary or secondary prevention of seizures after stroke. This was a prospective randomised, double-blind, placebo-controlled trial comparing valproic acid with placebo for primary prevention of seizures in 72 adults (over 18 years of age) with spontaneous non-aneurysmal, non-traumatic intracerebral haemorrhage; no statistically significant difference in outcome (seizure occurrence at one year) was demonstrated between groups. AUTHORS' CONCLUSIONS: Currently, there is insufficient evidence to support the routine use of antiepileptic drugs for the primary or secondary prevention of seizures after stroke. Further well-conducted research is needed for this important clinical problem.published_or_final_versio

Applications of satellite technology to broadband ISDN networks

Two satellite architectures for delivering broadband integrated services digital network (B-ISDN) service are evaluated. The first is assumed integral to an existing terrestrial network, and provides complementary services such as interconnects to remote nodes as well as high-rate multicast and broadcast service. The interconnects are at a 155 Mbs rate and are shown as being met with a nonregenerative multibeam satellite having 10-1.5 degree spots. The second satellite architecture focuses on providing private B-ISDN networks as well as acting as a gateway to the public network. This is conceived as being provided by a regenerative multibeam satellite with on-board ATM (asynchronous transfer mode) processing payload. With up to 800 Mbs offered, higher satellite EIRP is required. This is accomplished with 12-0.4 degree hopping beams, covering a total of 110 dwell positions. It is estimated the space segment capital cost for architecture one would be about $190M whereas the second architecture would be about$250M. The net user cost is given for a variety of scenarios, but the cost for 155 Mbs services is shown to be about $15-22/minute for 25 percent system utilization

Management of Asymptomatic Severe Aortic Stenosis

Patients with symptomatic severe aortic stenosis (AS) benefit from aortic valve replacement surgery, but the management of patients with asymptomatic severe AS is more controversial. While cholesterol and angiotensin have been linked to AS progression, we should await the results of ongoing randomized trials before medical therapy to lower cholesterol or inhibit angiotensin can be recommended to limit disease progression. Clinical factors, echocardiographic parameters, valve morphology, exercise stress testing results, and cardiac biomarkers may be useful in identifying patients who will have early development of symptoms during follow-up and require closer monitoring. The risks associated with aortic valve replacement outweigh the benefits in the majority of patients with asymptomatic severe AS

Disputing the Character of the City: Heritage, Regeneration and the Urban Design Turn

Like many cities with an abundant legacy of heritage structures and aspirations to expand their economic and population base, Halifax (Nova Scotia) experiences significant tensions between heritage conservation and urban development ambitions. On the one hand, Halifax has a vigorous heritage movement spawned in the wake of slum clearance and urban redevelopment efforts in the 1960s; heritage advocates work consistently to conserve the low-rise character of the historic city. On the other hand, it has an emergent urban design lobby supported by economic development interests and creative class ideas; development advocates call for signature high-rise buildings to attract investment and young people. With each new development proposal, community groups argue about the meaning of past and future, the nature of cultural identity and the image of the city. In this essay we examine the recent emergence of a social network of young urban professionals whose influence is growing rapidly in local debates about urban regeneration. Whereas a decade ago heritage conservation enjoyed high priority in planning debates in many parts of the world, today it competes with arguments for signature architecture and greater urban density. The urban design turn reflects changing cultural priorities but also reveals the operation of new governance mechanisms within local growth machines