Measurement and simulation of laser-induced fluorescence from non-equilibrium ultracold neutral plasmas

We report new measurements and simulations of laser-induced fluorescence in ultracold neutral plasmas. We focus on the earliest times, when the plasma equilibrium is evolving and before the plasma expands. In the simulation, the ions interact via the Yukawa potential in a small cell with wrapped boundary conditions. We solve the optical Bloch equation for each ion in the simulation as a function of time. Both the simulation and experiment show the initial Bloch vector rotation, disorder-induced heating, and coherent oscillation of the rms ion velocity. Detailed modeling of the fluorescence signal makes it possible to use fluorescence spectroscopy to probe ion dynamics in ultracold and strongly coupled plasmas

Measurement and simulation of laser-induced fluorescence from non-equilibrium ultracold neutral plasmas

We report new measurements and simulations of laser-induced fluorescence in ultracold neutral plasmas. We focus on the earliest times, when the plasma equilibrium is evolving and before the plasma expands. In the simulation, the ions interact via the Yukawa potential in a small cell with wrapped boundary conditions. We solve the optical Bloch equation for each ion in the simulation as a function of time. Both the simulation and experiment show the initial Bloch vector rotation, disorder-induced heating, and coherent oscillation of the rms ion velocity. Detailed modeling of the fluorescence signal makes it possible to use fluorescence spectroscopy to probe ion dynamics in ultracold and strongly coupled plasmas

Three participatory geographers: reflections on positionality and working with participants in researching religions, spiritualities, and faith

This paper advances the geographies of religion, spirituality and faith's limited attention to positionality by discussing the critical issues raised when using participatory approaches. Reflecting on three cases of participatory research, we foreground the dynamics of being a researcher with faith when working with participants from faith communities. Advocating participatory approaches as valuable methodologies that should be used more extensively to explore beliefs, faith practices, and social justice, we argue that greater attention needs to be given to the positionality of researchers undertaking this sort of research. Our cases raise three themes for discussion. First, the variety of ways in which faith positionalities influence how research is developed, conducted and concluded. Second, the intersections between our faith and other positionalities and how they shape our roles and relationships with research participants. Third, the fluid and multifaceted nature of faith positionalities and how they are changed, emphasized, and softened through the dynamics and entanglements of fieldwork. In doing so, we reflect on the complexities of being a researcher with faith, argue that faith positionality is a helpful dimension of their research rather than a limitation, and that all cultural, social and historical geographical researchers should reflect on their faith positionality

Advances in understanding the interaction between the gut microbiota and adaptive mucosal immune responses

Commensal gut bacteria are necessary for the complete development of mucosal innate and adaptive immunity and thus may influence intestinal and systemic immune disorders. Recent work has advanced our understanding of this association by identification of a single taxon of the murine microbiota which can stimulate T-cell development and differentiation. It is hoped that further characterization of the mechanisms involved will enable targeted manipulation of the microbiota-immune system relationship

Non-interference for deterministic interactive programs

We consider the problem of defining an appropriate notion of non-interference (NI) for deterministic interactive programs. Previous work on the security of interactive programs by O'Neill, Clarkson and Chong (CSFW 2006) builds on earlier ideas due to Wittbold and Johnson (Symposium on Security and Privacy 1990), and argues for a notion of NI defined in terms of strategies modelling the behaviour of users. We show that, for deterministic interactive programs, it is not necessary to consider strategies and that a simple stream model of the users' behaviour is sufficient. The key technical result is that, for deterministic programs, stream-based NI implies the apparently more general strategy-based NI (in fact we consider a wider class of strategies than those of O'Neill et al). We give our results in terms of a simple notion of Input-Output Labelled Transition System, thus allowing application of the results to a large class of deterministic interactive programming languages

INTERIM REPORT IMPROVED METHODS FOR INCORPORATING RISK IN DECISION MAKING

This paper reports observations and preliminary investigations in the first phase of a research program covering methodologies for making safety-related decisions. The objective has been to gain insight into NRC perceptions of the value of formal decision methods, their possible applications, and how risk is, or may be, incorporated in decision making. The perception of formal decision making techniques, held by various decision makers, and what may be done to improve them, were explored through interviews with NRC staff. An initial survey of decision making methods, an assessment of the applicability of formal methods vis-a-vis the available information, and a review of methods of incorporating risk and uncertainty have also been conducted

Global Estimates of PBL Depth from Space-Borne LIDAR

The planetary boundary layer (PBL) is responsible for communicating the exchange of energy, moisture, momentum, pollutants, and aerosols between the surface and the free atmosphere and is therefore crucial to many studies of the atmosphere. Unfortunately, there have historically been few observations of this important layer due to the complexity involved in its measurement. However, with the advent of more advanced satellites, global measurements of the PBL are now becoming possible. The PBL is often characterized by a high concentration of aerosols within the layer and low level clouds capping it and these are observable from space. The Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite was launched in 2006 with the intention of observing aerosols and clouds and was the first space-based LIDAR optimized for this purpose. CALIPSO observations are therefore well suited to observing the depth of the PBL. Since it was launched, CALIPSO has been making nearly continuous measurements enabling a global picture of PBL depth. We plan to present a global PBL depth product and how it evolves throughout the year. The product is able to identify deeper PBL depths in the summer hemisphere over land and deeper depths along the northern hemisphere oceanic storm tracks in winter associated with cold air traveling over warm water. Large seasonal cycles are also evident in the subtropical desert locations among other features. In addition, comparisons will be made between several estimates of PBL depth based on turbulent intensity, meteorology profiles, and aerosol profiles from the GEOS5 model

Survival following the placement of gastrostomy tube in patients with multiple sclerosis

Background Around a third of people with multiple sclerosis (MS) experience dysphagia. There is a need for disease-specific information on survival following placement of gastrostomy tube in people with MS. Objective We aimed to study survival following gastrostomy in patients with MS. Methods We reviewed medical records, home enteral feeding database and death certificates of people with MS who had gastrostomy from 2005 to 2017. Cox regression analysis was performed to identify independent predictors associated with mortality after gastrostomy. Results Median survival of 53 patients with MS after gastrostomy was 21.73 months. Median duration of hospital stay after gastrostomy was 14 days (IQR 5.25, 51.5). Survival at 30 days, 3 months, 1, 2, 5 and 10 years were 100% (53/53), 98.1% (52/53), 81.1% (43/53), 54.7% (29/53), 22.4% (11/49) and 6.8% (3/44), respectively. Of 53 patients, 24 died due to respiratory tract infection. Patients who had gastrostomy tube before 50 years of age survived longer (median 28.48 months) compared with those who had the gastrostomy after age 50 years (median 17.51 months) (p = 0.040). Conclusion Around 54% of patients with MS survived two or more years following gastrostomy. Younger patients had better survival. The most frequent cause of death was respiratory infection

Detecting control flow in Smarphones: Combining static and dynamic analyses

International audienceSecurity in embedded systems such as smartphones requires protection of confidential data and applications. Many of security mechanisms use dynamic taint analysis techniques for tracking information flow in software. But these techniques cannot detect control flows that use conditionals to implicitly transfer information from objects to other objects. In particular, malicious applications can bypass Android system and get privacy sensitive information through control flows. We propose an enhancement of dynamic taint analysis that propagates taint along control dependencies by using the static analysis in embedded system such as Google Android operating system. By using this new approach, it becomes possible to protect sensitive information and detect most types of software exploits without reporting too many false positives