Snap Shots Research Articles

“They are all Turks, but very very nice”: Re-placing contemporary artists of Turkish origin

Contemporary visual artists from Turkey, who have left their ‘home’ for various reasons, such as migration or education, have emerged as a distinctive voice on the contemporary European art scene. What makes these artists pertinent for an analysis of new forms of identity and citizenship making, and the negotiation of belonging and mobility in contemporary Europe is that their art presents the sheer diversity of artistic approaches that address, incorporate, and fold cultural interaction as well as confrontation with the identitary and cultural ‘container’ that is Western Europe. This paper will focus on three cases, Nevin Aladag, Anny and Sibel Ozturk, and Nilbar Gures, querying whether and how their artistic gaze can provide critical insight into the diverse possibilities of relations between Turkey and Western Europe. Using their works as laboratories or ‘snap shots’ of identity negotiations, this paper will query how mobility and transnational encounters shape artistic production, and how, in turn, such transnational and intercultural works can shed new light on the making of contemporary European identities ‘beyond borders’ that integrates Turkey through art.

Pressure and Draw-In Maps for Stamping Process Monitoring

This paper presents two tooling-integrated sensing techniques for the in situ measurement and analyses of pressure distribution at the tool–workpiece interface and material draw-in during the stamping processes. Specifically, the contact pressure distribution is calculated from the measurements by an array of force sensors embedded in the punch, whereas sheet draw-in is measured by custom-designed thin film sensors integrated in the binder. Quantification of the pressure distribution from spatially distributed sensors has been investigated as a regularization problem and solved through energy minimization. Additionally, a Bayesian framework has been established for combining finite-element analysis (FEA) based estimates of the pressure distribution with experimentally measured evidence, to achieve improved spatiotemporal resolution. A new data visualization technique termed pressure and draw-in (PDI) map has been introduced, which combine spatiotemporal information from the two sensing techniques into an illustrative representation by capturing both the tool–workpiece interaction (dynamic information) and resulting workpiece motion (kinematic information) in a series of time-stamped snap shots. Together, the two separate yet complementary process-embedded sensing methods present an effective tool for quantifying process variations in sheet metal stamping and enable new insight into the underlying physics of the process.

Butterfly community shifts over two centuries.

Environmental changes strongly impact the distribution of species and subsequently the composition of species assemblages. Although most community ecology studies represent temporal snap shots, long-term observations are rather rare. However, only such time series allow the identification of species composition shifts over several decades or even centuries. We analyzed changes in the species composition of a southeastern German butterfly and burnet moth community over nearly 2 centuries (1840-2013). We classified all species observed over this period according to their ecological tolerance, thereby assessing their degree of habitat specialisation. This classification was based on traits of the butterfly and burnet moth species and on their larval host plants. We collected data on temperature and precipitation for our study area over the same period. The number of species declined substantially from 1840 (117 species) to 2013 (71 species). The proportion of habitat specialists decreased, and most of these are currently endangered. In contrast, the proportion of habitat generalists increased. Species with restricted dispersal behavior and species in need of areas poor in soil nutrients had severe losses. Furthermore, our data indicated a decrease in species composition similarity between different decades over time. These data on species composition changes and the general trends of modifications may reflect effects from climate change and atmospheric nitrogen loads, as indicated by the ecological characteristics of host plant species and local changes in habitat configuration with increasing fragmentation. Our observation of major declines over time of currently threatened and protected species shows the importance of efficient conservation strategies.

Which CT Set for Lung SBRT Planning: The Effect of Varying Lung Density on Monte Carlo Dose Calculation

Free-breathing (FB) and average CTs are common CT images used for SBRT lung planning. The FB CT, a fast 3D scan, consists of random snap shots at different breathing phases for different CT bed positions. The average CT, often created as a mean intensity projection from a slow 4D CT, represents a time-averaged anatomy. While the average CT has been shown to be advantageous for GTV contouring and target localization, both are believed to be equivalent for dose calculation with conventional algorithms (pencil beam, convolution superposition). Since previous studies demonstrated considerable MC dose dependence on varying lung densities, whether in phantoms or between patients with different lung densities, we aimed to study the lung density variation between FB and average CTs, and its effect on MC dose calculation increasingly used in lung SBRT planning. With IRB approval, 10 previously-treated lung SBRT patients were randomly chosen. For each patient, both a FB CT and an 8-phase 4D CT were acquired. The 4D CT was used for contouring an ITV while the FB CT was used for treatment planning with dynamic conformal arcs in clinical treatments. Lungs were contoured on the FB CT, on each phase of the 4D CT, and on an average CT created from the 4D CT. Lung density was compared for each patient among these 10 different data sets. Dose distribution was calculated with MC (iPlan, BrainLab) on FB and average CTs for dose comparison using D5, Dmean and D95 of PTV and GTV, as well as RTOG 0813 protocol compliance. Wilcoxon’s signed rank test was used. For the 10 studied patients, the median (range) of the minimum, mean, and maximum lung density from the 4D CT was 0.26 (0.10∼0.34), 0.31 (0.12∼0.43), 0.35 (0.22∼0.51) g/cc, respectively. Using the mean lung density from the 4D CT as the gold standard, the median (range) deviation of that on the FB and average CT was -0.03 (-0.09∼0.02) and 0.00 (-0.01∼0.01) g/cc, respectively. For the PTV, the median (range) D5, Dmean and D95 percent difference between the FB and average CT dose calculation was -1.9 (-5.1∼1.2%), -0.2 (-1.1∼0.4%) and -1.1 (-4.3∼0.7%), and for the GTV, -1.0 (-2.9∼0.8%), -0.2 (-0.4∼0.3%) and -0.8 (-2.4∼0.5%), respectively. There was no dose index difference that was statistically significant (P< 0.05) for the studied population. RTOG compliance was not different between the two CT sets for any patient. Lung density on the average CT accurately represents the mean density from the 4D CT. Varying density differences were observed between the average and FB CTs, hence leading to varying dosimetric differences in MC dose calculated. However, for the 10 studied patients, the dosimetric differences were not statistically significant. This suggests that negligible difference between FB and average CT is expected for MC calculation, similar to what previously believed true for conventional dose algorithms.

The Neighboring Column Approximation (NCA) – A fast approach for the calculation of 3D thermal heating rates in cloud resolving models

Due to computational costs, radiation is usually neglected or solved in plane parallel 1D approximation in today's numerical weather forecast and cloud resolving models. We present a fast and accurate method to calculate 3D heating and cooling rates in the thermal spectral range that can be used in cloud resolving models. The parameterization considers net fluxes across horizontal box boundaries in addition to the top and bottom boundaries. Since the largest heating and cooling rates occur inside the cloud, close to the cloud edge, the method needs in first approximation only the information if a grid box is at the edge of a cloud or not. Therefore, in order to calculate the heating or cooling rates of a specific grid box, only the directly neighboring columns are used. Our so-called Neighboring Column Approximation (NCA) is an analytical consideration of cloud side effects which can be considered a convolution of a 1D radiative transfer result with a kernel or radius of 1 grid-box (5pt stencil) and which does usually not break the parallelization of a cloud resolving model. The NCA can be easily applied to any cloud resolving model that includes a 1D radiation scheme. Due to the neglect of horizontal transport of radiation further away than one model column, the NCA works best for model resolutions of about 100m or lager.In this paper we describe the method and show a set of applications of LES cloud field snap shots. Correction terms, gains and restrictions of the NCA are described. Comprehensive comparisons to the 3D Monte Carlo Model MYSTIC and a 1D solution are shown. In realistic cloud fields, the full 3D simulation with MYSTIC shows cooling rates up to −150K/d (100m resolution) while the 1D solution shows maximum coolings of only −100K/d. The NCA is capable of reproducing the larger 3D cooling rates. The spatial distribution of the heating and cooling is improved considerably. Computational costs are only a factor of 1.5–2 higher compared to a 1D solution.

Haar Features Based Face Detection andRecognition for Advanced Classroom andCorporate Attendance

Face of a person is its recognition. Methods are implemented to exploit this physical feature have seen a great change after the image processing techniques came into existence. The attendance is taken in every schools, colleges, library and corporate offices. It takes some time to record attendance.In this approach, we are using face detection and recognition system. This face detection differentiates faces from non-faces and is therefore essential for accurate attendance. To avoid wastage in time, we are about to use an automatic process which is based on image processing. In the present approach along with the face recognition we are using face detection system. This face detection system detects faces of individuals on the basis of intensities of pixels in the snap shots. The ARM Processor module is used for displaying Number of Presentees and the people present. The camera will be connected to the ARM. The student or employees database is collected. The database includes name of the students/employees, there images. This webcam module will be installed at the front side of class in such a way that it can capture entire class or in front of a main office door. Thus with the help of this system, time will be saved and it will be very much convenient to record attendance.

Subduction, peak and multi-stage exhumation metamorphism: Traces from one coesite-bearing eclogite, Tso Morari, western Himalaya

Ultrahigh-pressure (UHP), coesite-bearing eclogites in the Himalaya have been documented from the Kaghan Valley in Pakistan and the Tso Morari area in northwest India. These complexes are part of the northern edge of the Indian plate that has been subducted to, and metamorphosed at, mantle depths of more than 100km before being exhumed. Both UHP complexes are located today directly adjacent to the Indus–Tsangpo suture zone and are not separated by non-metamorphosed sequences of Tethyan sediments from the Asian margin. Herein, we present new data for one fresh coesite-bearing eclogite from the Tso Morari massif. Therein, garnets are zoned reflecting their growth during prograde and peak metamorphism and showing a thin retrograde overgrowth. Inclusions can be directly correlated to the compositional zoning and are seen as either relicts of the protolith mineral paragenesis and as “snap shots” of the mineral paragenesis during subduction and under peak conditions. Rare earth element concentrations (REE) were obtained for garnet, mineral inclusions in garnet and matrix minerals. The REE pattern in garnet reflects a sequential change in matrix minerals and their proportions due to net transfer reactions during subduction and peak metamorphism. Using conventional geothermobarometry, a peak pressure of ca. 44–48kbar at 560–760°C followed by an S-shaped exhumation curve has been deduced. Gibbs free energy minimization modelling was used to supplement our analytical findings.

Fluorescence fluctuation microscopy: a diversified arsenal of methods to investigate molecular dynamics inside cells

Fluorescence microscopy provides insight into the subcellular organization of biological functions. However, images are snap shots averaging over a highly dynamic molecular system. Fluorescence fluctuation microscopy, employing similar detection technology, encompasses a powerful arsenal of analysis tools that investigate the molecular heterogeneity in space and time. Analyzing signal fluctuations from small ensembles (several hundred particles) reveals their concentration, the stoichiometry, the stochastic motion, as well as superimposed signatures of the environment such as spatial confinement and binding events. Thus, fluctuation analysis provides access to dynamic molecular properties that can be used to build physical models of cellular processes. In the last decade these methods experienced a remarkable diversification, which we revisit here with a particular focus on live cell applications.

Surface Atomic Diffusion Processes Observed at Milliseconds Time Resolution using Environmental TEM

Significant progress has been made in spatial resolution using environmental transmission electron microscopes (ETEM), which now enables atomic resolution visualization of structural transformation under variable temperature and gas environments close to materials real operational conditions. Structural transformations are observed by recording images or diffraction patterns at various time intervals using a video camera or by taking snap shots using electron pulses. While time resolution at 15 ns has been reported using pulsed electron beams, the time interval that can be recorded by this technique is currently very limited. For longer recording, however, time resolution inside ETEM has been limited by electron cameras to ~1/30 seconds for a long time. Using the recently developed direct electron detection technology, we have significantly improved the time resolution of ETEM to 2.5 ms (milliseconds) for full frame or 0.625 ms for 0.25 frames.

Surveillance of C-allocation in microalgal cells.

When microalgae are exposed to changing environmental conditions, e.g., light-dark cycles or oscillations in nutrient availability (CO2, nitrogen, phosphate or silicate) they respond with metabolic changes in the carbon allocation pattern. Short time regulations in the time range of few seconds to minutes can be mirrored best by mass spectroscopy based metabolomics. However, these snap shots do not reflect the alterations in the carbon flow to the cellular macromolecules like protein, carbohydrate or lipid. In this review it is shown how the combination of FTIR spectroscopy and Chla-in-vivo-fluorescence based electron transport rates can reveal changes in the metabolic flux rates of carbon during a shift of the environmental conditions. The review will demonstrate in which time range FTIR spectroscopy can deliver significant information and how FTIR spectroscopy data can synergistically support metabolome analysis by mass-spectroscopy.

Microstructure of Gold Nano-Crystals from Nanometer to Micrometer Lengthscale in Gold Bulk Metallic Glass

Gold based bulk metallic glass was synthesized at with different quenching rates. Au54Ag5Pd2Cu24.3Si14.7 alloy ingots were cast into wedge shape and cone shape samples. The critical casting thickness of this alloy composition was found to be 4 mm when cast in copper mold. Completely amorphous structure as found in sections thinner than 4 mm when considering a infinite copper plate geometry. In locations with slower cooling rates, there are small fractions of transformed nanocrystals. The transmission electron microscope (TEM) study of Au54Ag5Pd2Cu24.3Si14.7 solidified microstructure could offer snap shots of nucleation and growth of crystals from nanometer to micrometer length-scale as evolved with different cooling rates. The phase evolution was recorded by transmission electron microscope study, electron diffraction and metallography using scanning electron microscope. The specimens comprised of both fully amorphous solid and nanocomposites which were the combination of nano-crystals of controlled sizes in amorphous matrix. Vickers hardness values increased to 350-450 Hv, when compared to sub 100-150 Hv level of conventional 18-k gold alloys as cast. The study offers a revolutionary way to create ultrahigh strength bulk metals that comprise of large percentage of nano-crystals in amorphous matrix.

Pattern formation in a mean field model of electrocortical activity

Mean field models of cortical activity describe the electrical potentials and interactions of cortical neuron populations, coarse-grained over the scale of a few macro columns. Such models can be analysed as dynamical systems, in particular as time-dependent partial differential or integro-differential equations, which may have complicating aspects such as explicit time delays and stochastic terms. We analyse a model of intermediate complexity, formulated by Liley et al. [1]. This model describes an excitatory and an inhibitory population in a simple geometry, on which the effect of long-range connections is represented by a damped wave equations. Although somewhat rudimentary from a physiological point of view, this model has been shown to predict several features of electrocortical dynamics rather well (see, e.g., [2,3] and refs therein) and is challenging to analyse mathematically. It consists of fourteen coupled partial differential equations with strong nonlinearities. Where previous analysis on this model, and similar mean-field models, has used drastic simplifications, such as reduction to zero or one spatial dimensions or a single population, we developed tools for parsing the dynamics of the full-fledged equations [4]. Using the open-source library PETSc [5], we have implemented fully implicit time-stepping for the field equations and the tangent linear model, as well as arclength continuation for equilibrium and time-periodic solutions. All computations are performed in parallel using domain decomposition. In the current application of these tools, we focus on physiologically interesting γ-range activity [3]. This activity is triggered by a Hopf bifurcation under small variations of the local inhibitory to inhibitory connection density. We computed the saddle-type periodic orbit that regulates the transient dynamics of perturbations to the base equilibrium state. Two snap shots of this orbit, computed on a 12.8 by 12.8 cm domain, with 0.5 mm resolution, are shown in Figure ​Figure1.1. The period of this orbit corresponds to a 12 Hz oscillation, whereas the final, attracting, state has a strong 40 Hz peak in the power spectrum [3]. Figure 1 Partial bifurcation diagram near the primary instability, which is a subcritical Hopf bifurcation. In ongoing work we are investigating bifurcations of this periodic orbit, which can turn completely stable or give rise to more complicated solutions, such as quasi-periodic or chaotic. This dynamical systems approach to the analysis of mean-field models should give us more insight in the complex model behaviour. Figure 2 Two snap shots of the excitatory membrane potential along the saddle periodic orbit. The potential ranges from -67 mV (dark red) to -52 mV (dark blue).

Experimental study of the internal flow structures inside a fluidic oscillator

The internal flow characteristics of a fluidic oscillator were investigated experimentally. Particle image velocimetry and time-resolved pressure measurements were employed in water to visualize and quantify the internal flow patterns. The method of proper orthogonal decomposition was applied to random flow field snap shots for phase reconstruction of one oscillation cycle. The resulting phase-averaged information provides detailed insight into the oscillation mechanism as well as into the interaction between the main chamber of the oscillator and its feedback channels. A growing recirculation bubble between the main jet and the attachment wall is identified as an underlying mechanism that causes the main jet to oscillate. The flow field measurements are complemented by time-resolved pressure measurements at various internal locations which yield additional comprehension of the switching behavior and accompanying timescales. Geometrical features, in particular at the inlet and outlet of the mixing chamber, are found to have a crucial impact on important flow characteristics such as oscillation frequency and jet deflection.

Bringing You Negative Selection, Live and in Color

Bringing You Negative Selection, Live and in Color

Serotonin and Dopamine Transporter Homology Models Provide a Look Inside the Active Site during Three Stages of Transport

The central nervous system is controlled by electrochemical impulses propagated through neurotransmitters, whose concentration and length of presence in the synapse determines the duration and the strength of the stimuli. Clearing of the neurotransmitters is the responsibility of specific transporters. The main ones being Serotonin, Dopamine, and Norepinephrine Transporters (SERT, DAT, and NET). As a class of secondary transporters the sodium: neurotransmitter symporters utilize a sodium ion gradient to co-transport a neurotransmitter molecule against its gradient. The coupling of the ions favourable free energy to the unfavourable recycling of the neurotransmitters is the crucial step in deciphering the mechanism of action. Our interests also expand into the substrate interaction with the transporter at the active site. Studying not just the interaction of the protein with the native substrate, but some known inhibitors will provide even more insight into the interactions at the active site. The inhibitors we are interested in are both of pharmaceutical and psychedelic origins. The interesting idea behind looking at both of these is the difference in addictiveness of one over the other. Different inhibitors will also have different modes of action and by exploiting these we can come up with more effective and less addictive drugs for treating many mood and neurodegenerative disorders. The first step in our approach will be to create hSERT and hDAT homology models using LeuT as a template. Each homology models will be modelled in three different states. The open-to-out, open-to-in, and fully occluded states will provide us with the “snap shots” during the transport. By analyzing the differences and similarities in ion coupling and substrate/inhibitor interactions clues to the overall mechanism will be obtained.

Mapping the Evolution of Molecular Flow Fields in Migrating Cells with Time-Resolved STICCS

Cell migration is a complex process that involves an intricate choreography between cytoskeleton and adhesion molecules with precise regulation of their transport and interactions in space and time in living cells. Although there have been many advances recently in improving spatial resolution of optical microscopy methods, temporal resolution remains a bottleneck for many methods. Previously we have reported spatio-temporal image cross-correlation spectroscopy (STICCS) in combination with TIRF microscopy to provide snap shots of flow fields of adhesion proteins and the cyctoskeleton in migrating cells. However, the temporal resolution of the STICCS transport maps was low compared to the frame time resolution of the TIRF imaging. Here we report the extension of STICCS to its absolute temporal resolution limit as set by the imaging frame rate by applying a short correlation window of 10 or fewer frames with the analysis window iterated sequentially by single frame steps. Although computationally more intensive, this enables us to capture the time evolution of the flow transport and interactions of adhesion components in living cells with a STICCS vector map for every frame of the TIRF movie. We illustrate the method with measurements of time evolving transport maps of the adhesion related macromolecules alpha5, alpha6 and alphaL integrins with paxillin, and actin within, or associated with the basal membrane in adherent U2OS and CHO.B2 cells plated on extracellular matrix components fibronectin, laminin, or ICAM-1. The time resolved cross-correlation vector maps clearly show that the dynamic interactions between alpha6 or alphaL integrins with paxillin evolve in space and time only at active adhesions in protruding and retracting regions of the cells.

NUMERICAL AND EXPERIMENTAL STUDY OF DAM-BREAK FLOOD PROPAGATION AND ITS IMPLICATION TO SEDIMENT EROSION

Regarding the hydrodynamics, within the past two decades it has become popular in numerical modeling of free-surface flow to adopt a Reynolds-averaged Navier-Stokes approach, where the volume of fluid (VOF) method is utilized to track the evolution of free-surface. However, this robust numerical model has not been widely applied to the study of sediment transport processes. In this study, we shall extend the numerical model to simulate suspended sediment transport and study the erosion pattern during the initial stage of the dam break flow. We also conducted a series of experiments in a horizontal channel of rectangular section and recorded the snap shots of surface profiles of a dam- break wave during the initial stage of dam-break. Measured data is utilized here to study the hydrodynamics and to validate the numerical model.

In vivo fluorescence imaging of apoptosis during foreign body response

Quantification of apoptotic tissues during inflammatory processes induced by biomaterials is challenging in vivo. Here we present a non-invasive method using a fluorescence imaging system which facilitates intermittent snap shots of the current state of local apoptotic tissue. For this purpose, apoptotic cells around two different subcutaneously implanted materials (titanium discs and copper-coated titanium discs) in hairless but immunocompetent mice were quantified after 4, 8 and 23 days of implantation. For validation, the results of fluorescence signals were compared to the histology of the inflammatory tissue using apoptotic-specific TUNEL-, macrophage-specific F4/80-, neutrophile-specific NIMP-R14- and chloroacetate esterase-staining. We could demonstrate that the fluorescence signals were well suited to quantify the extent of apoptosis in vivo and this is a good indication for the biocompatibility of biomaterials. This study shows that non-invasive monitoring of tissue processes following the implantation of biomaterials is possible in vivo and may help to reduce the number of animals in studies addressing biocompatibility.

Minimization of drive tests solution in 3GPP

Providing network coverage and quality of service (QoS) is an important task of a cellular network operator. This is because cellular spectrum is normally licensed under certain coverage obligations, and operators need to be competitive in market. To improve their networks, operators often send engineers in the field to collect radio measurements, to discover problems such as coverage holes in the network, and to determine whether certain parameter tuning is needed. However, such conventional tests require large Operation Expenditure (OPEX), while the collected measurements can only give limited snap shots of the entire network. In their Release 10 (Rel-10) specification, 3GPP studied and specified solutions to reduce this OPEX for drive tests, under the work item named ?Minimization of Drive Tests (MDT). The solution utilizes the user (customer) equipments (UEs) to collect field measurements, including radio measurements and location information. This article describes in details the solution adopted in 3GPP MDT; how they were developed and intended to be used.

PMO-011 Evaluating participants' experiences of the bowel screening Wales service

IntroductionThe aim of the study is to evaluate participants' opinions on their experience of the Bowel Screening Wales (BSW) service and thus provide a snapshot view of the programme.MethodsThe primary...