User requirements for location based services : an analysis on the basis of literature

The high global penetration of mobile telephony provides a strong basis for the development and diffusion of mobile business applications. Especially for location based services, i.e. mobile services that consider the user’s current location to add value to the service provided, a high potential to become a major market success is seen. Nevertheless the development of mobile business and location based services has so far been lagging behind expert expecations. One of the reasons for this disappointing development is the failure of application developers to center their efforts on potential users and their needs and demands. The following paper therefore reviews the existing literature on user requirements in mobile business and location based services. A definition and characterization of location based services is given and a framework to categorize existing location based services is developed. Additionally, usefulness and usability are put in concrete terms as they are identified as the main determinants of end-user acceptance of location based services. Security concerns of potential users of location based services are analyzed and further limitations of the diffusion of location based services are discussed

Location Based Services in Deutschland : eine qualitative Marktanalyse auf Basis von Experteninterviews

Trotz der hohen Potenzialeinschätzungen für Location Based Services (LBS) ist die Entwicklung des LBS-Marktes in Deutschland bisher hinter den Erwartungen zurückgeblieben. Die Ursachen hierfür sind bisher weder auf Praxis- noch auf Forschungsseite identifiziert und ausführlich analysiert worden. Die vorliegende Untersuchung zielt daher darauf ab, die Gründe für die hinter den Erwartungen zurück bleibende Entwicklung herauszuarbeiten. Hierzu wird eine qualitative Expertenbefragung in der LBS-Branche durchgeführt. Als Ergebnis der Untersuchung erweisen sich neben technischen Barrieren insbesondere die Unwissenheit und Verunsicherung auf Seiten der Nutzer als Diffusionshemmnisse von LBS. Zudem zeigt sich, dass die derzeitige Struktur der Wertschöpfungskette suboptimal für eine erfolgreiche Marktentwicklung ist. Chancen für die Diffusion von LBS stellen nach Ansicht der befragten Experten die allgemeine gesellschaftliche Entwicklung, der Trend zu Mobilität sowie der Druck zu erhöhter Produktivität und Effizienz dar. Schließlich lassen sich aus den Befragungsergebnissen fünf zentrale Herausforderungen ableiten, welche von den Anbietern ortsbezogener Dienste zu adressieren sind

Mehrwertorientierte Gestaltung mobiler Dienste im Fahrzeug : eine empirische Untersuchung von Nutzeranforderungen

Stagnierende Märkte und veränderte Kundenanforderungen eröffnen in der Automobilindustrie die Suche nach neuen, Erfolg versprechenden Geschäftsmodellen. Automobilhersteller entdecken dabei zune hmend das Potenzial des Mobile Business, sehen sich bei der Erweiterung ihres ur sprünglichen Kerngeschäftes durch die Integration von mobilen Diensten in das Fahrzeug jedoch gleichzeitig mit neuen Herausforderungen konfrontiert. Um in den Augen der Nachfrager einen erkennbaren Mehrwert zu stiften und somit die nutzerseitige Akzeptanz von mobilen Diensten im Fahrzeug zu sichern, müssen sich die Anbieter verstärkt an den Bedürfnissen ihrer Kunden orientieren. Ausgangspunkt für die vorliegende Arbeit, der en zentrales Ziel die Identifizierung und Analyse nutzenstiftender Elemente von mobilen Diensten ist, sind die bisher geringen Forschungsaktivitäten im Hinblick auf eine kundenorientierte Gestaltung von mobilen Anwendungen im Fahrzeug. Eine Expertenbefragung soll zunächst Aufschluss über die zentralen Eigenschaft en des Leistungsbündels „mobile Dienste“ geben. Anschließend erfolgt auf Grundlage einer internetbasierten Konsumentenbefragung eine Analyse der Präferenzstrukturen von potenziellen Nutzern mobiler Dienste im Rahmen einer Adaptiven Conjoint-Analyse. Im letzten Untersuchungsschritt werden mittels einer Clusteranalyse homogene Käufergruppen identifiziert und segmentspezifische Gestaltungsempfehlungen abgeleitet

Elevated α-synuclein caused by SNCA gene triplication impairs neuronal differentiation and maturation in Parkinson's patient-derived induced pluripotent stem cells

We have assessed the impact of a-synuclein overexpression on the differentiation potential and phenotypic signatures of two neural-committed induced pluripotent stem cell lines derived from a Parkinson's disease patient with a triplication of the human SNCA genomic locus. In parallel, comparative studies were performed on two control lines derived from healthy individuals and lines generated from the patient iPS-derived neuroprogenitor lines infected with a lentivirus incorporating a small hairpin RNA to knock down the SNCA mRNA. The SNCA triplication lines exhibited a reduced capacity to differentiate into dopaminergic or GABAergic neurons and decreased neurite outgrowth and lower neuronal activity compared with control cultures. This delayed maturation phenotype was confirmed by gene expression profiling, which revealed a significant reduction in mRNA for genes implicated in neuronal differentiation such as delta-like homolog 1 (DLK1), gamma-aminobutyric acid type B receptor subunit 2 (GABABR2), nuclear receptor related 1 protein (NURR1), G-protein-regulated inward-rectifier potassium channel 2 (GIRK-2) and tyrosine hydroxylase (TH). The differentiated patient cells also demonstrated increased autophagic flux when stressed with chloroquine. We conclude that a two-fold overexpression of a-synuclein caused by a triplication of the SNCA gene is sufficient to impair the differentiation of neuronal progenitor cells, a finding with implications for adult neurogenesis and Parkinson's disease progression, particularly in the context of bioenergetic dysfunction.Instituto de Investigaciones Bioquímicas de La Plat

The Combined Dexamethasone/CRH Test (DEX/CRH Test) and Prediction of Acute Treatment Response in Major Depression

In this study the predictive value of the combined dexamethasone/CRH test (DEX/CRH test) for acute antidepressant response was investigated. In 114 depressed inpatients suffering from unipolar or bipolar depression (sample 1) the DEX/CRH test was performed at admission and shortly before discharge. During their stay in the hospital patients received different antidepressant treatment regimens. At admission, the rate of nonsuppression (basal cortisol levels >75.3 nmol/l) was 24.6% and was not related to the later therapeutic response. Moreover, 45 out of 114 (39.5%) patients showed an enhancement of HPA axis function at discharge in spite of clinical improvement. In a second sample, 40 depressed patients were treated either with reboxetine or mirtazapine for 5 weeks. The DEX/CRH test was performed before, after 1 week, and after 5 weeks of pharmacotherapy. Attenuation of HPA axis activity after 1 week was associated with a more pronounced alleviation of depressive symptoms after 5-week mirtazapine treatment, whereas downregulation of HPA system activity after 5 weeks was related to clinical response to reboxetine. However, early improvement of HPA axis dysregulation was not necessarily followed by a beneficial treatment outcome. Taken together, performance of a single DEX/CRH test does not predict the therapeutic response. The best predictor for response seems to be an early attenuation of HPA axis activity within 1 or 2 weeks. However, early improvement of HPA system dysfunction is not a sufficient condition for a favourable response. Since a substantial part of depressive patients display a persistence of HPA axis hyperactivity at discharge, downregulation of HPA system function is not a necessary condition for acute clinical improvement either. Our data underline the importance of HPA axis dysregulation for treatment outcome in major depression, although restoration of HPA system dysfunction seems to be neither a necessary nor a sufficient determinant for acute treatment response

A Full Computation-relevant Topological Dynamics Classification of Elementary Cellular Automata

Cellular automata are both computational and dynamical systems. We give a complete classification of the dynamic behaviour of elementary cellular automata (ECA) in terms of fundamental dynamic system notions such as sensitivity and chaoticity. The "complex" ECA emerge to be sensitive, but not chaotic and not eventually weakly periodic. Based on this classification, we conjecture that elementary cellular automata capable of carrying out complex computations, such as needed for Turing-universality, are at the "edge of chaos"

Thermodynamics of impurity-enhanced vacancy formation in metals

Hydrogen induced vacancy formation in metals and metal alloys has been of great interest during the past couple of decades. The main reason for this phenomenon, often referred to as the superabundant vacancy formation, is the lowering of vacancy formation energy due to the trapping of hydrogen. By means of thermodynamics, we study the equilibrium vacancy formation in fcc metals (Pd, Ni, Co, and Fe) in correlation with the H amounts. The results of this study are compared and found to be in good agreement with experiments. For the accurate description of the total energy of the metal-hydrogen system, we take into account the binding energies of each trapped impurity, the vibrational entropy of defects, and the thermodynamics of divacancy formation. We demonstrate the effect of vacancy formation energy, the hydrogen binding, and the divacancy binding energy on the total equilibrium vacancy concentration. We show that the divacancy fraction gives the major contribution to the total vacancy fraction at high H fractions and cannot be neglected when studying superabundant vacancies. Our results lead to a novel conclusion that at high hydrogen fractions, superabundant vacancy formation takes place regardless of the binding energy between vacancies and hydrogen. We also propose the reason of superabundant vacancy formation mainly in the fcc phase. The equations obtained within this work can be used for any metal-impurity system, if the impurity occupies an interstitial site in the lattice. Published by AIP Publishing.Peer reviewe

Neurofilaments in spinocerebellar ataxia type 3: blood biomarkers at the preataxic and ataxic stage in humans and mice

With molecular treatments coming into reach for spinocerebellar ataxia type 3 (SCA3), easily accessible, cross-species validated biomarkers for human and preclinical trials are warranted, particularly for the preataxic disease stage. We assessed serum levels of neurofilament light (NfL) and phosphorylated neurofilament heavy (pNfH) in ataxic and preataxic subjects of two independent multicentric SCA3 cohorts and in a SCA3 knock-in mouse model. Ataxic SCA3 subjects showed increased levels of both NfL and pNfH. In preataxic subjects, NfL levels increased with proximity to the individual expected onset of ataxia, with significant NfL elevations already 7.5 years before onset. Cross-sectional NfL levels correlated with both disease severity and longitudinal disease progression. Blood NfL and pNfH increases in human SCA3 were each paralleled by similar changes in SCA3 knock-in mice, here also starting already at the presymptomatic stage, closely following ataxin-3 aggregation and preceding Purkinje cell loss in the brain. Blood neurofilaments, particularly NfL, might thus provide easily accessible, cross-species validated biomarkers in both ataxic and preataxic SCA3, associated with earliest neuropathological changes, and serve as progression, proximity-to-onset and, potentially, treatment-response markers in both human and preclinical SCA3 trials