Pressure-driven flow of suspensions: simulation and theory

Dynamic simulations of the pressure-driven flow in a channel of a non-Brownian suspension at zero Reynolds number were conducted using Stokesian Dynamics. The simulations are for a monolayer of identical particles as a function of the dimensionless channel width and the bulk particle concentration. Starting from a homogeneous dispersion, the particles gradually migrate towards the centre of the channel, resulting in an homogeneous concentration profile and a blunting of the particle velocity profile. The time for achieving steady state scales as (H/a)3a/[left angle bracket]u[right angle bracket], where H is the channel width, a the radii of the particles, and [left angle bracket]u[right angle bracket] the average suspension velocity in the channel. The concentration and velocity profiles determined from the simulations are in qualitative agreement with experiment. A model for suspension flow has been proposed in which macroscopic mass, momentum and energy balances are constructed and solved simultaneously. It is shown that the requirement that the suspension pressure be constant in directions perpendicular to the mean motion leads to particle migration and concentration variations in inhomogeneous flow. The concept of the suspension ‘temperature’ – a measure of the particle velocity fluctuations – is introduced in order to provide a nonlocal description of suspension behaviour. The results of this model for channel flow are in good agreement with the simulations

Teaching the normal and the pathological:Educational technologies and the material reproduction of medicine

That pathology and normality exist on a complex spectrum of bodily manifestation is an enduring problem at the heart of the philosophy, anthropology and history of medicine. As the primary locus for the reproduction of medicine, medical schools are important sites for cultivating knowledge of what is normal and what is not. Here students come to engage with the slippery concepts of normality and pathology in collaboration with a wide range of educational technologies - the cadavers, plastic models, illustrations and diagnostic tools which corral student knowledge of the body in both health and disease. These technologies are not universally employed across medical faculties, and variations in their use contributes to various constructions of pathology and normality. Ethnographic observation and historical research in medical faculties in Hungary, the Netherlands and Ghana, shows that educational practices are shaped by the epistemic traditions which manifest in the material environment of the medical school, and that these different sociomaterial settings contribute to inconsistent notions of normalcy. Although educational technologies often tend towards fixity in their representations of the body in health and disease, medical school practice in the north of Ghana resists the imposition of the often alien standards typically found in teaching materials imported from Europe or North America. By teaching around and beyond these materials, Ghanaian educators also challenge their assuredness and the intellectual history of contemporary medicine

Integration and Optimization of UUV/USV Operations in Environmental Characterization

John Joseph, Doug Horner and Bradley NottThis research is an initial investigation into the potential application of an integrated system consisting of unmanned surface vessel (USV) and unmanned underwater vehicle (UUV) components in support of wide-area environmental sensing and characterization. The project was suggested as a topic of interest by CNO N2/N6 which has been contemplating the development of a USV program under the Navyﾒs Littoral Battlespace Sensing Program of Record. A comprehensive theoretical, modeling and observational approach was used to weigh strengths and limitations of an integrated system that leverages use of available unmanned system technology to develop an effective integrated system for characterizing both the oceanographic and acoustic environments supporting undersea warfare (USW) and battlespace awareness (BA) missions. The study was largely conducted as the basis for thesis research conducted by LT Bradley Nott, a USW curriculum student who recently graduated with his MS Physical Oceanography degree in September 2015 (http://hdl.handle.net/10945/47308).Naval Research ProgramPrepared for: CNO N2/N6, Sponsor POC Name: CDR Nick Vincen

Monte Carlo sampling from the quantum state space. II

High-quality random samples of quantum states are needed for a variety of tasks in quantum information and quantum computation. Searching the high-dimensional quantum state space for a global maximum of an objective function with many local maxima or evaluating an integral over a region in the quantum state space are but two exemplary applications of many. These tasks can only be performed reliably and efficiently with Monte Carlo methods, which involve good samplings of the parameter space in accordance with the relevant target distribution. We show how the Markov-chain Monte Carlo method known as Hamiltonian Monte Carlo, or hybrid Monte Carlo, can be adapted to this context. It is applicable when an efficient parameterization of the state space is available. The resulting random walk is entirely inside the physical parameter space, and the Hamiltonian dynamics enable us to take big steps, thereby avoiding strong correlations between successive sample points while enjoying a high acceptance rate. We use examples of single and double qubit measurements for illustration.Comment: 11 pages, 4 figures, 12 reference

Monte Carlo sampling from the quantum state space. I

High-quality random samples of quantum states are needed for a variety of tasks in quantum information and quantum computation. Searching the high-dimensional quantum state space for a global maximum of an objective function with many local maxima or evaluating an integral over a region in the quantum state space are but two exemplary applications of many. These tasks can only be performed reliably and efficiently with Monte Carlo methods, which involve good samplings of the parameter space in accordance with the relevant target distribution. We show how the standard strategies of rejection sampling, importance sampling, and Markov-chain sampling can be adapted to this context, where the samples must obey the constraints imposed by the positivity of the statistical operator. For a comparison of these sampling methods, we generate sample points in the probability space for two-qubit states probed with a tomographically incomplete measurement, and then use the sample for the calculation of the size and credibility of the recently-introduced optimal error regions [see New J. Phys. 15 (2013) 123026]. Another illustration is the computation of the fractional volume of separable two-qubit states.Comment: 13 pages, 5 figures, 1 table, 26 reference

The dancing front: dancing, morale, and the war effort in Britain during World War II

During the Second World War dancing boomed. This article, which discusses social dancing in Britain during the war, is oriented towards questions of morale; the “myth of the Blitz”; and the evolution of attitudes towards popular culture. It looks at how the unofficial efforts of dance hall owners dovetailed with official government efforts to raise morale; how such efforts shared in national myth making, creating a host of images and examples of philanthropy and bravery vital to patriotic propaganda. It also examines how the dance hall industry successfully navigated the challenges of wartime in order to alter perceptions about dancing and secure both its immediate and long-term future. Despite serving important functions, social dancing’s role in the war effort has received little detailed attention. Where it has been studied, emphasis has been placed on episodes of racially motivated conflict at dances, primarily between American GIs. This article will thus provide the first detailed examination of dancing’s wider wartime role. Moreover, it speaks to several key aspects of the historiography of the Second World War and of twentieth century British popular culture. It provides new evidence for the use of recreation and leisure as a strategy for boosting morale during the war. It helps us better understand the nature of propaganda and morale boosting measures taken during the war and highlights the often sluggish response of the government to utilizing all avenues of propaganda. Furthermore, it allows us to consider changing attitudes towards popular culture during wartime.PostprintPeer reviewe

Professional Reading: Can America Win the Next War?

Believing that conflict characterizes human affairs and that the Soviet leadership considers conflict inevitable and is preparing for it, Drew Middleton, long a military correspondent for The New York Times, suggests that sooner or later the United States may be at war again

S-nitrosation of proteins relevant to Alzheimer's disease during early stages of neurodegeneration

Protein S-nitrosation (SNO-protein), the nitric oxide-mediated posttranslational modification of cysteine thiols, is an important regulatory mechanism of protein function in both physiological and pathological pathways. A key first step toward elucidating the mechanism by which S-nitrosation modulates a protein's function is identification of the targeted cysteine residues. Here, we present a strategy for the simultaneous identification of SNO-cysteine sites and their cognate proteins to profile the brain of the CK-p25-inducible mouse model of Alzheimer's disease-like neurodegeneration. The approach-SNOTRAP (SNO trapping by triaryl phosphine)-is a direct tagging strategy that uses phosphinebased chemical probes, allowing enrichment of SNO-peptides and their identification by liquid chromatography tandem mass spectrometry. SNOTRAP identified 313 endogenous SNO-sites in 251 proteins in the mouse brain, of which 135 SNO-proteins were detected only during neurodegeneration. S-nitrosation in the brain shows regional differences and becomes elevated during early stages of neurodegeneration in the CK-p25 mouse. The SNO-proteome during early neurodegeneration identified increased S-nitrosation of proteins important for synapse function, metabolism, and Alzheimer's disease pathology. In the latter case, proteins related to amyloid precursor protein processing and secretion are S-nitrosated, correlating with increased amyloid formation. Sequence analysis of SNO-cysteine sites identified potential linear motifs that are altered under pathological conditions. Collectively, SNOTRAP is a direct tagging tool for global elucidation of the SNO-proteome, providing functional insights of endogenous SNO proteins in the brain and its dysregulation during neurodegeneration.National Institutes of Health (U.S.) (Grant CA26731)National Institutes of Health (U.S.) (Grant R01 NS051874

S-nitrosation of proteins relevant to Alzheimer’s disease during early stages of neurodegeneration

Protein S-nitrosation (SNO-protein), the nitric oxide-mediated posttranslational modification of cysteine thiols, is an important regulatory mechanism of protein function in both physiological and pathological pathways. A key first step toward elucidating the mechanism by which S-nitrosation modulates a protein’s function is identification of the targeted cysteine residues. Here, we present a strategy for the simultaneous identification of SNO-cysteine sites and their cognate proteins to profile the brain of the CK-p25–inducible mouse model of Alzheimer’s disease-like neurodegeneration. The approach—SNOTRAP (SNO trapping by triaryl phosphine)—is a direct tagging strategy that uses phosphine-based chemical probes, allowing enrichment of SNO-peptides and their identification by liquid chromatography tandem mass spectrometry. SNOTRAP identified 313 endogenous SNO-sites in 251 proteins in the mouse brain, of which 135 SNO-proteins were detected only during neurodegeneration. S-nitrosation in the brain shows regional differences and becomes elevated during early stages of neurodegeneration in the CK-p25 mouse. The SNO-proteome during early neurodegeneration identified increased S-nitrosation of proteins important for synapse function, metabolism, and Alzheimer’s disease pathology. In the latter case, proteins related to amyloid precursor protein processing and secretion are S-nitrosated, correlating with increased amyloid formation. Sequence analysis of SNO-cysteine sites identified potential linear motifs that are altered under pathological conditions. Collectively, SNOTRAP is a direct tagging tool for global elucidation of the SNO-proteome, providing functional insights of endogenous SNO proteins in the brain and its dysregulation during neurodegeneration.National Institutes of Health (U.S.) (NIH Grant CA26731)Massachusetts Institute of Technology. Center for Environmental Health Sciences (Grant ES002109)Simons FoundationNational Institutes of Health (U.S.) (NIH Grant R01 NS051874