Fully Discrete Pointwise Smoothing Error Estimates for Measure Valued Initial Data

In this paper we analyze a homogeneous parabolic problem with initial data in the space of regular Borel measures. The problem is discretized in time with a discontinuous Galerkin scheme of arbitrary degree and in space with continuous finite elements of orders one or two. We show parabolic smoothing results for the continuous, semidiscrete and fully discrete problems. Our main results are interior $L^\infty$ error estimates for the evaluation at the endtime, in cases where the initial data is supported in a subdomain. In order to obtain these, we additionally show interior $L^\infty$ error estimates for $L^2$ initial data and quadratic finite elements, which extends the corresponding result previously established by the authors for linear finite elements

Ostwald ripening in Two Dimensions: Correlations and Scaling Beyond Mean Field

We present a systematic quasi-mean field model of the Ostwald ripening process in two dimensions. Our approach yields a set of dynamic equations for the temporal evolution of the minority phase droplets' radii. The equations contain only pairwise interactions between the droplets; these interactions are evaluated in a mean- field type manner. We proceed to solve numerically the dynamic equations for systems of tens of thousands of interacting droplets. The numerical results are compared with the experimental data obtained by Krichevsky and Stavans for the relatively large volume fraction $\phi=0.13$. We found good agreement with experiment even for various correlation functions.Comment: 29 pages, RevTex, 5 eps figure

Elevated impulsivity and impaired decision-making cognition in heavy users of MDMA ("Ecstasy”)

Rationale: In animal studies, the common club drug 3,4-methylendioxymethamphetamine (MDMA, "Ecstasy”) consistently caused a prolonged loss of presynaptic serotonergic neurons, and evidence suggests that MDMA consumption may also affect the human serotonergic system. Serotonin (5-HT) has been implicated in the regulation of impulsivity and such executive functions as decision-making cognition. In fact, MDMA users have shown elevated impulsivity in two studies, but little is known about decision making in drug-free MDMA consumers. Objective: The aim of this study was to examine the cognitive neurotoxicity of MDMA with regard to behavioral impulsivity and decision-making cognition. Methods: Nineteen male, abstinent, heavy MDMA users; 19 male, abstinent cannabis users; and 19 male, drug-naïve controls were examined with the Matching Familiar Figures Test (MFFT) as well as with a Go/No-Go Task (GNG) for impulsivity and with a Gambling Task (GT) for executive functioning. Results: MDMA users showed significantly elevated impulsivity in the MFFT Impulsivity score (I-score), but not in commission errors of the GNG, compared with controls. Cannabis users did not yield altered impulsivity compared with controls. In the GT, MDMA users performed significantly worse than cannabis consumers and controls, whereas cannabis users exhibited the same decision-making capacity as controls. In addition, the I-score as well as the decision-making performance was correlated with measures of MDMA intake. The I-score and the decision-making performance were also correlated. Conclusion: These results suggest that heavy use of MDMA may elevate behavioral impulsivity and impair decision-making cognition possibly mediated by a selective impairment of the 5-HT syste

The cratering record of Ganymede and the origin of potential impactors: open issues

The origin of impactors on the Galilean satellites of Jupiter is an open question. In this study we present results from a mapping campaign based on reprocessed Voyager and Galileo SSI images in order to derive a thourough data base of Ganymede's crater distributions

Performance measurement in a transitional economy: unfolding a case of KPIs

Purpose The purpose of this paper aims to make contributions to the debate on “performance measurement in practice” focussing on how organisational participants respond to the “new regime” of key performance indicators (KPIs) and whether KPIs materialise as intended in a transitional economy. Design/methodology/approach Inspired by the epistemological instruction of Schatzki's practice theory, this paper draws on qualitative data collected through face-to-face interviews, observations and documentary analysis of a single organisation. Findings KPIs were introduced at PK (a manufacturing concern in Czech Republic) but widely seen as contradictory, inconsequential, top-down and unrealistic. These lead organisational participants to adopt a pragmatic approach towards PM embracing KPIs' subjective assessment and manipulation, common sense or doing the job as given, and superficial compliance (symbolism). Research limitations/implications The paper would be interesting to researchers because of its explanation of performance measurement practice in a distinct empirical setting, for its application of a practice theory inspired by Schatzki, and for inspiring new research agendas in transitional economies. Practical implications The paper recommends the mobilisation of artefacts, such as various forms of bottom-up discussions, to encourage interactions between organisational members and influence individual beliefs and practical understandings of the intended managerial projects. Originality/value The paper has focussed on “organisations of practice” to unravel the “doings” of organisational participants to explore the micro-processes of PM which otherwise would have been ignored. These “doings” and “sayings”, linked by pools of understanding, rules or instructions, and a teleoaffective structure, enabled the authors to unmask inherent tensions and contradictions in a new regime of performance measures such as KPIs

Neurofunctional differences and similarities between persistent postural-perceptual dizziness and anxiety disorder

Introduction: Persistent postural-perceptual dizziness (PPPD) (ICD-11) and anxiety disorders (ANX) share behavioural symptoms like anxiety, avoidance, social withdrawal, hyperarousal, or palpitation as well as neurological symptoms like vertigo, stance and gait disorders. Furthermore, previous studies have shown a bidirectional link between vestibulo-spatial and anxiety neural networks. So far, there have been no neuroimaging-studies comparing these groups. Objectives: The aim of this explorative study was to investigate differences and similarities of neural correlates between these two patient groups and to compare their findings with a healthy control group. Methods: 63 participants, divided in two patient groups (ANX = 20 and PPPD = 14) and two sex and age matched healthy control groups (HC-A = 16, HC-P = 13) were included. Anxiety and dizziness related pictures were shown during fMRI-measurements in a block-design in order to induce emotional responses. All subjects filled in questionnaires regarding vertigo (VSS, VHQ), anxiety (STAI), depression (BDI-II), alexithymia (TAS), and illness-perception (IPQ). After modelling the BOLD response with a standard canonical HRF, voxel-wise t-tests between conditions (emotional-negative vs neutral stimuli) were used to generate statistical contrast maps and identify relevant brain areas (pFDR 30 voxels). ROI-analyses were performed for amygdala, cingulate gyrus, hippocampus, inferior frontal gyrus, insula, supramarginal gyrus and thalamus (p ≤ 0.05). Results: Patient groups differed from both HC groups regarding anxiety, dizziness, depression and alexithymia scores; ratings of the PPPD group and the ANX group did differ significantly only in the VSS subscale ‘vertigo and related symptoms’ (VSS-VER). The PPPD group showed increased neural responses in the vestibulo-spatial network, especially in the supramarginal gyrus (SMG), and superior temporal gyrus (STG), compared to ANX and HC-P group. The PPPD group showed increased neural responses compared to the HC-P group in the anxiety network including amygdala, insula, lentiform gyrus, hippocampus, inferior frontal gyrus (IFG) and brainstem. Neuronal responses were enhanced in visual structures, e.g. fusiform gyrus, middle occipital gyrus, and in the medial orbitofrontal cortex (mOFC) in healthy controls compared to patients with ANX and PPPD, and in the ANX group compared to the PPPD group. Conclusions: These findings indicate that neuronal responses to emotional information in the PPPD and the ANX group are comparable in anxiety networks but not in vestibulo-spatial networks. Patients with PPPD revealed a stronger neuronal response especially in SMG and STG compared to the ANX and the HC group. These results might suggest higher sensitivity and poorer adaptation processes in the PPPD group to anxiety and dizziness related pictures. Stronger activation in visual processing areas in HC subjects might be due to less emotional and more visual processing strategies

Digitalisierung im Verkehrswasserbau: BIM, Semantic Web und IoT-Sensorik

Der Verkehrswasserbau soll die Sicherheit und Zuverlässigkeit der Schifffahrt gewährleisten. Damit verknüpft sind Aufgaben wie z.B. der Hochwasserschutz, die Wasserkraftnutzung, Be- und Entwässerung sowie Freizeitgestaltung. Im Vergleich zu den Verkehrsträgern Schiene und Straße haben Wasserstraßen eine un-gleich größere Vielfalt an Bauwerken, Bauwerksfunktionen und -belastungen, was bei deren Planung, Bemessung, Konstruktion, Überwachung und Sanierung zu speziellen Anforderungen insbesondere im Hinblick auf die Digitalisierung führt. Für etliche Ingenieuraufgaben an verkehrswasserbaulichen Anlagen gilt es daher, eine Vielzahl von Bauwerksparametern digital zu erfassen, zu modellieren und auszuwerten. Building Information Modeling (BIM) stellt eine zielführende digitale Methode dar, Bauwerke anhand eines konsistenten, digitalen Anlagenmodells über ihren gesamten Lebenszyklus mit all ihren relevanten Informationen und zu-gehörigen Prozessen abzubilden. Ergänzend ergeben sich speziell für die Datenerfassung vor Ort mit der IoT-Sensorik (IoT: Internet of Things) neue effiziente Möglichkeiten der digitalen Überwachung. Zusätzlich können existierende Datenbestände mit Methoden des Semantic Web in einer föderalen Umgebung verfüg-bar gemacht werden. Am Beispiel des Verkehrswasserbaus werden integrale Digitalisierungspotentiale von BIM, IoT-Sensorik und Semantic Web aufgezeigt

Cognitive and functional deficits are associated with white matter abnormalities in two independent cohorts of patients with schizophrenia

BACKGROUND Significant evidence links white matter (WM) microstructural abnormalities to cognitive impairment in schizophrenia (SZ), but the relationship of these abnormalities with functional outcome remains unclear. METHODS In two independent cohorts (C1, C2), patients with SZ were divided into two subgroups: patients with higher cognitive performance (SZ-HCP-C1, n = 25; SZ-HCP-C2, n = 24) and patients with lower cognitive performance (SZ-LCP-C1, n = 25; SZ-LCP-C2, n = 24). Healthy controls (HC) were included in both cohorts (HC-C1, n = 52; HC-C2, n = 27). We compared fractional anisotropy (FA) of the whole-brain WM skeleton between the three groups (SZ-LCP, SZ-HCP, HC) by a whole-brain exploratory approach and an atlas-defined WM regions-of-interest approach via tract-based spatial statistics. In addition, we explored whether FA values were associated with Global Assessment of Functioning (GAF) scores in the SZ groups. RESULTS In both cohorts, mean FA values of whole-brain WM skeleton were significantly lower in the SCZ-LCP group than in the SCZ-HCP group. Whereas in C1 the FA of the frontal part of the left inferior fronto-occipital fasciculus (IFOF) was positively correlated with GAF score, in C2 the FA of the temporal part of the left IFOF was positively correlated with GAF score. CONCLUSIONS We provide robust evidence for WM microstructural abnormalities in SZ. These abnormalities are more prominent in patients with low cognitive performance and are associated with the level of functioning