Crucial role of sidewalls in velocity distributions in quasi-2D granular gases

Our experiments and three-dimensional molecular dynamics simulations of particles confined to a vertical monolayer by closely spaced frictional walls (sidewalls) yield velocity distributions with non-Gaussian tails and a peak near zero velocity. Simulations with frictionless sidewalls are not peaked. Thus interactions between particles and their container are an important determinant of the shape of the distribution and should be considered when evaluating experiments on a tightly constrained monolayer of particles.Comment: 4 pages, 4 figures, Added reference, model explanation charified, other minor change

The Perspective of College Seniors in ROTC on Becoming a Commissioned Officer

While there is growing research into Military and Mental health issues, the focus of such research has primarily been restricted to those populations who are retired from Military or who step-down from Active Duty. Following a case study with Reservists, we became aware that mental health issues in the Military Population may potentially stem from concepts involved the initial training phases. With the hypothesis that ROTC Cadets are among the youngest persons engaging in Military training, we approached ROTC Air Force and ROTC Army Cadets who were Seniors by credit at Cedarville University. The Cadets were asked to participate in a face-to-face interview with a researcher, to share their experiences of ROTC and their perspectives on what life as a Commissioned Officer would be like. Participation in the interviews was voluntary, but the Air Force Commander and Army Commander had informed their Cadets that this study had been approved by them and participation was encouraged. Participants included both male and female Cadets from a broad range of academic majors. The interviews were analyzed and six themes emerged:- (a) Being associated with high caliber professionals (b) Balancing military persona with non-military persona (c) Skills and strategies for success in life (d) Personal values (e) Awareness of challenges (f) Impact of training on persona. Overall, the Cadets expressed excitement at the prospect of becoming Commissioned Officers, and pride in being among those who serve their country

Onset of Patterns in an Ocillated Granular Layer: Continuum and Molecular Dynamics Simulations

We study the onset of patterns in vertically oscillated layers of frictionless dissipative particles. Using both numerical solutions of continuum equations to Navier-Stokes order and molecular dynamics (MD) simulations, we find that standing waves form stripe patterns above a critical acceleration of the cell. Changing the frequency of oscillation of the cell changes the wavelength of the resulting pattern; MD and continuum simulations both yield wavelengths in accord with previous experimental results. The value of the critical acceleration for ordered standing waves is approximately 10% higher in molecular dynamics simulations than in the continuum simulations, and the amplitude of the waves differs significantly between the models. The delay in the onset of order in molecular dynamics simulations and the amplitude of noise below this onset are consistent with the presence of fluctuations which are absent in the continuum theory. The strength of the noise obtained by fit to Swift-Hohenberg theory is orders of magnitude larger than the thermal noise in fluid convection experiments, and is comparable to the noise found in experiments with oscillated granular layers and in recent fluid experiments on fluids near the critical point. Good agreement is found between the mean field value of onset from the Swift-Hohenberg fit and the onset in continuum simulations. Patterns are compared in cells oscillated at two different frequencies in MD; the layer with larger wavelength patterns has less noise than the layer with smaller wavelength patterns.Comment: Published in Physical Review

Successful identification of pathogens by polymerase chain reaction (PCR)-based electron spray ionization time-of-flight mass spectrometry (ESI-TOF-MS) in culture-negative periprosthetic joint infection.

BACKGROUND: The diagnosis of periprosthetic joint infection poses many challenges, one of which is the difficulty of isolating the infecting organism. Recently, a sophisticated modality (the Ibis Biosciences T5000 biosensor system) has been introduced that uses pan-domain primers in a series of polymerase chain reactions (PCRs) to identify and speciate essentially all bacteria and fungi as well as to identify key antibiotic resistance genes. We investigated the role of the Ibis in identifying infecting organisms in cases of known and suspected periprosthetic joint infection. METHODS: Synovial fluid specimens were collected prospectively from eighty-two patients undergoing eighty-seven arthroplasty procedures (sixty-five knee revisions, fifteen hip revisions, and seven primary knee arthroplasties) and were sent for both conventional culture and Ibis analysis. The surgeon\u27s clinical determination of the cause for revision arthroplasty was failure due to infection in twenty-three cases and noninfectious failure in fifty-seven cases. RESULTS: In the twenty-three cases that were considered on clinical grounds to involve a periprosthetic joint infection, the Ibis detected the same pathogen isolated by conventional culture in seventeen of eighteen cases and also detected one or more organisms in four of the five culture-negative cases. In addition, the Ibis detected organisms in fifty (88%) of the fifty-seven cases in which revision arthroplasty was performed for a presumed noninfectious failure. CONCLUSIONS: The Ibis technology was not only effective at detecting organisms in cases of suspected periprosthetic joint infection in which cultures were negative, but it also suggested that many of the revision arthroplasty cases that have previously been considered to be purely aseptic may have a component of unrecognized, subclinical infection

Pressure Modulator Radiometer (PMR) tests

The pressure modulator technique was evaluated for monitoring pollutant gases in the Earth's atmosphere of altitude levels corresponding to the mid and lower troposphere. Using an experimental set up and a 110 cm sample cell, pressure modulator output signals resulting from a range of gas concentrations in the sample cell were examined. Then a 20 cm sample cell was modified so that trace gas properties in the atmosphere could be simulated in the laboratory. These gas properties were measured using an infrared sensor

Fredholm Indices and the Phase Diagram of Quantum Hall Systems

The quantized Hall conductance in a plateau is related to the index of a Fredholm operator. In this paper we describe the generic ``phase diagram'' of Fredholm indices associated with bounded and Toeplitz operators. We discuss the possible relevance of our results to the phase diagram of disordered integer quantum Hall systems.Comment: 25 pages, including 7 embedded figures. The mathematical content of this paper is similar to our previous paper math-ph/0003003, but the physical analysis is ne

Innovative biomarkers to predict unfavourable outcomes after initiating multiple sclerosis treatment

Over the last decade, more than ten new disease modifying treatments (DMTs) for multiple sclerosis (MS) have been approved and introduced into routine clinical care. All have demonstrated improved efficacy in limiting ongoing inflammation and tissue damage in MS patients, but many have potentially serious side effect profiles that require more careful monitoring than previous baseline therapies. Together with the tendency for earlier introduction of high efficacy DMTs, the risk that patients will encounter adverse events will increase over time. Identifying biomarkers which enable accurate prediction of prognosis and treatment response has become a major challenge to those working in the field. In this journal club, we describe three novel studies aiming to predict and detect serious side effects associated with MS treatments