Is there a Superior Distance Function for Matching in Small Samples?

The study contributes to the development of ’standards’ for the application of matching algorithms in empirical evaluation studies. The focus is on the first step of the matching procedure, the choice of an appropriate distance function. Supplementary o most former studies, the simulation is strongly based on empirical evaluation ituations. This reality orientation induces the focus on small samples. Furthermore, ariables with different scale levels must be considered explicitly in the matching rocess. The choice of the analysed distance functions is determined by the results of former theoretical studies and recommendations in the empirical literature. Thus, in the simulation, two balancing scores (the propensity score and the index score) and the Mahalanobis distance are considered. Additionally, aggregated statistical distance functions not yet used for empirical evaluation are included. The matching outcomes are compared using non-parametrical scale-specific tests for identical distributions of the characteristics in the treatment and the control groups. The simulation results show that, in small samples, aggregated statistical distance functions are the better choice for summarising similarities in differently scaled variables compared to the commonly used measures.distance functions, matching, microeconometric evaluation, propensity score, simulation

Sniping in Online-Auktionen

In Online-Auktionen werden Gebote oft gezielt kurz vor Ende der Auktion abgegeben. Diese als Sniping bezeichnete Bietstrategie hat zum Ziel, einen starken Preisanstieg durch wechselseitiges Überbieten zu vermeiden. Obwohl Sniping in Online-Auktionen häufig auftritt, konnten bisherige empirische Untersuchungen keine statistisch gesicherten Preiseffekte nachweisen. Die vorliegende Analyse zeigt die Profitabilität von Sniping anhand einer empirischen Studie und unter-sucht mögliche Wirkungszusammenhänge anhand statistischer Merkmale

Shilling in Online-Auktionen

Online-Auktionen sind neben anderen Manipulationen insbeson-dere dem sogenannten Shilling ausgesetzt. Dabei bietet ein Ver-käufer unter falscher Identität in einer eigenen Auktion, um da-durch einen Vorteil zu erlangen. Dieser Beitrag schlägt ein neues Verfahren zur Identifikation dieser schwer erkennbaren Manipula-tionsform vor. Die bisher bekannten Ansätze werden um eine stochastische Analyse und das Konzept einer Indizien-Signatur erweitert, um eine höhere Trennschärfe hinsichtlich verschiedener Formen des Shilling zu erzielen. Dieses Verfahren wird anschlie-ßend auf Daten des Online-Auktionshauses eBay angewendet und zeigt die hohe Praxisrelevanz der Shilling-Manipulationen

Der Fachkräfteneubedarf in Thüringen bis 2015: Prognose und Handlungsoptionen

We forecast the number of qualified workers required in the German federal state Thuringia until 2015 on the basis of the manpower requirement approach. Disaggregated by types of qualification, this method distinguishes between two sources of recruitment requirements: replacement demand for old workers and expansion demand to reflect structural changes of industry sectors and productivity growth. Both components are calculated from register data on employment covered by social security. Relative to current employment, recruitment requirements vary across occupations. A comparison of recruitment requirements for medium-skilled workers with the structure of vocational training reveals potential mismatch between demand and supply of medium-skilled labor in the near future if the composition of apprenticeship programs remains unchanged. The study closes with policy recommendations to prevent occupational mismatch.

The Janthinobacterium sp. HH01 genome encodes a homologue of the V. cholerae CqsA and L. pneumophila LqsA autoinducer synthases

Janthinobacteria commonly form biofilms on eukaryotic hosts and are known to synthesize antibacterial and antifungal compounds. Janthinobacterium sp. HH01 was recently isolated from an aquatic environment and its genome sequence was established. The genome consists of a single chromosome and reveals a size of 7.10 Mb, being the largest janthinobacterial genome so far known. Approximately 80% of the 5,980 coding sequences (CDSs) present in the HH01 genome could be assigned putative functions. The genome encodes a wealth of secretory functions and several large clusters for polyketide biosynthesis. HH01 also encodes a remarkable number of proteins involved in resistance to drugs or heavy metals. Interestingly, the genome of HH01 apparently lacks the N-acylhomoserine lactone (AHL)-dependent signaling system and the AI-2-dependent quorum sensing regulatory circuit. Instead it encodes a homologue of the Legionella- and Vibrio-like autoinducer (lqsA/cqsA) synthase gene which we designated jqsA. The jqsA gene is linked to a cognate sensor kinase (jqsS) which is flanked by the response regulator jqsR. Here we show that a jqsA deletion has strong impact on the violacein biosynthesis in Janthinobacterium sp. HH01 and that a jqsA deletion mutant can be functionally complemented with the V. cholerae cqsA and the L. pneumophila lqsA genes

An evidence map of systematic reviews on models of outpatient care for patients with chronic heart diseases

Abstract Background Chronic heart disease affects millions of people worldwide and the prevalence is increasing. By now, there is an extensive literature on outpatient care of people with chronic heart disease. We aimed to systematically identify and map models of outpatient care for people with chronic heart disease in terms of the interventions included and the outcomes measured and reported to determine areas in need of further research. Methods We created an evidence map of published systematic reviews. PubMed, Cochrane Library (Wiley), Web of Science, and Scopus were searched to identify all relevant articles from January 2000 to June 2021 published in English or German language. From each included systematic review, we abstracted search dates, number and type of included studies, objectives, populations, interventions, and outcomes. Models of care were categorised into six approaches: cardiac rehabilitation, chronic disease management, home-based care, outpatient clinic, telemedicine, and transitional care. Intervention categories were developed inductively. Outcomes were mapped onto the taxonomy developed by the COMET initiative. Results The systematic literature search identified 8043 potentially relevant publications on models of outpatient care for patients with chronic heart diseases. Finally, 47 systematic reviews met the inclusion criteria, covering 1206 primary studies (including double counting). We identified six different models of care and described which interventions were used and what outcomes were included to measure their effectiveness. Education-related and telemedicine interventions were described in more than 50% of the models of outpatient care. The most frequently used outcome domains were death and life impact. Conclusion Evidence on outpatient care for people with chronic heart diseases is broad. However, comparability is limited due to differences in interventions and outcome measures. Outpatient care for people with coronary heart disease and atrial fibrillation is a less well-studied area compared to heart failure. Our evidence mapping demonstrates the need for a core outcome set and further studies to examine the effects of models of outpatient care or different interventions with adjusted outcome parameters. Systematic review registration PROSPERO (CRD42020166330)

Nanosession: Variants of Resistive Switching

International audienc