701 research outputs found

    Crowdfunding Success: A Perspective from Social Media and E-Commerce

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    Crowdfunding as a new way of financing in the web 2.0 has increased over the last years, but only little is known how project initiators increase their chances of successful fundraising through on-page and off-page communication activities. Using a dataset of 740 projects published on one of the dominant crowdfunding platforms in Switzerland, we test communication-related determinants of fundraising success in terms of (1) number of donations (2) average amount of donations and (3) total campaign success. Our results show that high media richness in the project presentation and a high frequency of project updates leverage fundraising success. In contrast, no beneficial effects of the simple application of social media channels could be observed. The implications for research on crowdfunding and practice are discussed

    Die Entwicklung Sozialer Netzwerke von Gründerteams. Formulierung, Implementierung und Anwendung eines kognitionsbasierten Simulationsmodells

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    Die Untersuchung befasst sich mit der Entwicklung Sozialer Netzwerke von Gründerteams. Dazu wurde ein kognitionsbasiertes Modell entwickelt, welches die Anbahnung, die Etablierung und den Abbruch von Geschäftsbeziehungen bei Gründerteams erfasst, sowie Tranksaktionen und Kommunikationen innerhalb von diesen. Das Modell wurde in einer Computersimulation implementiert, validiert und angewandt. Aus dem beobachteten Verhalten der Computersimulation heraus wurden 22 Propositionen über die Entwicklung Sozialer Netzwerke von Gründerteams abgeleitet

    Quo vadis Deutschlandstipendium: Studie zur Spenden- und Stipendienkultur in Deutschland

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    Clinical application of a simple questionnaire for the differentiation of asthma and chronic obstructive pulmonary disease

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    AbstractBackground: Asthma and chronic obstructive pulmonary disease (COPD) are highly prevalent chronic diseases characterized by airflow limitation. Both diseases have a distinct pathogenesis and require unique treatment approaches. Due to some common characteristic traits, asthma and COPD are often lumped together in clinical practice. We sought to develop a simple questionnaire for the distinction of asthma and COPD.Methods: Clinical discriminants of asthma and COPD were retrospectively identified by multiple logistic regression using files from 547 consecutive adult patients presenting to a pulmonary specialist practice with a diagnosis of asthma or COPD. With these features, we generated a simple quantitative questionnaire supporting a diagnosis of COPD with high scores and asthma with low scores (range 0–15 points). Questionnaire results were compared with physician's diagnosis based on GINA and GOLD guidelines including skin tests, spirometry and reversibility data.Results: 210 patients had COPD and 337 had asthma. Age of onset, smoking history, atopy status, and cough quality were significantly associated with a diagnosis of asthma or COPD. Questionnaire scores for COPD patients were higher than those for asthmatics (mean score 10.5±0.18 vs. 4±0.12, P<0.0001). Receiver operational characteristics (ROC) analysis revealed a cutoff score of 7 with the highest discriminant power (87.6% sensitivity, 87.2% specificity for COPD, 87.4% correctly classified, area under the ROC curve: 0.954). The overlap between asthma and COPD (score 6–8) comprised about 20% of the total population, these patients included a higher proportion of COPD patients with atopy, and smoking asthmatics.Conclusions: In patients with obstructive airway diseases, a simple questionnaire can support the differentiation of asthma and COPD in everyday clinical practice. Further prospective trials are necessary to confirm these initial observations

    Constraints on mantle evolution from Ce-Nd-Hf isotope systematics

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    Mantle evolution is governed by continuous depletion by partial melting and replenishment by recycling oceanic and continental crust. Several important unknowns remain, however, such as the extent of compositional variability of the residual depleted mantle, the timescale, mass flux and composition of recycled oceanic and continental crust. Here, we investigate the Ce-Nd-Hf isotope systematics in a globally representative spectrum of mid ocean ridge and ocean island basalts. Using a Monte Carlo approach for reproducing the observed Ce-Nd-Hf isotope variation shows that the type and age of depleted mantle and recycled crust have the dominant influence on the slope, scatter, and extent of the modeled Ce-Nd-Hf isotope array. The model results suggest a relatively young (Peer reviewe

    Plasma levels of osteopontin from birth to adulthood

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    Aim Osteopontin (OPN) has been investigated as a biomarker for cancer and nonmalignant diseases during the last decades. Data about OPN as a potential biomarker in childhood diseases are still sparse, and reference values are not available in children. We aimed to establish reference values for children from birth to young adulthood and evaluate whether there are age‐, gender‐, and weight‐specific differences. Method Umbilical cord blood and blood plasma samples of 117 children were collected in the Children's Hospital of Saarland University in Homburg/Saar. OPN levels were measured by ELISA, and statistical analysis was performed using SPSS software. Results Neonates, infants, toddlers, young children, adolescents, and adults were divided into the following six age groups: newborns (birth), infancy and toddlers (0‐24 months), early childhood (3‐6 years), middle childhood (7‐11 years), adolescence (12‐18 years), and adults (> 18 years). Highest blood OPN levels were found in the group of 0‐1 years of age. OPN blood levels declined significantly with age (Spearman r = −0.874; P < 0.001). Conclusion Our work is the first prospective and systematic study analyzing OPN cord blood and blood plasma levels in children of all ages. It is the first study yielding reference values for different age groups from birth to young adulthood. Our data give insight on how OPN in umbilical cord blood and OPN in blood plasma are physiologically influenced during childhood development and growth with high OPN levels after birth and a constant age‐related decline until the age of 14, when OPN levels reach similar values to those measured in adults

    Mapping historical forest biomass for stock-change assessments at parcel to landscape scales

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    Understanding historical forest dynamics, specifically changes in forest biomass and carbon stocks, has become critical for assessing current forest climate benefits and projecting future benefits under various policy, regulatory, and stewardship scenarios. Carbon accounting frameworks based exclusively on national forest inventories are limited to broad-scale estimates, but model-based approaches that combine these inventories with remotely sensed data can yield contiguous fine-resolution maps of forest biomass and carbon stocks across landscapes over time. Here we describe a fundamental step in building a map-based stock-change framework: mapping historical forest biomass at fine temporal and spatial resolution (annual, 30m) across all of New York State (USA) from 1990 to 2019, using freely available data and open-source tools. Using Landsat imagery, US Forest Service Forest Inventory and Analysis (FIA) data, and off-the-shelf LiDAR collections we developed three modeling approaches for mapping historical forest aboveground biomass (AGB): training on FIA plot-level AGB estimates (direct), training on LiDAR-derived AGB maps (indirect), and an ensemble averaging predictions from the direct and indirect models. Model prediction surfaces (maps) were tested against FIA estimates at multiple scales. All three approaches produced viable outputs, yet tradeoffs were evident in terms of model complexity, map accuracy, saturation, and fine-scale pattern representation. The resulting map products can help identify where, when, and how forest carbon stocks are changing as a result of both anthropogenic and natural drivers alike. These products can thus serve as inputs to a wide range of applications including stock-change assessments, monitoring reporting and verification frameworks, and prioritizing parcels for protection or enrollment in improved management programs.Comment: Manuscript: 24 pages, 7 figures; Supplements: 12 pages, 5 figures; Submitted to Forest Ecology and Managemen

    Array-based analysis of genomic DNA methylation patterns of the tumour suppressor gene p16(INK4A) promoter in colon carcinoma cell lines

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    Aberrant DNA methylation at CpG dinucleotides can result in epigenetic silencing of tumour suppressor genes and represents one of the earliest events in tumourigenesis. To date, however, high-throughput tools that are capable of surveying the methylation status of multiple gene promoters have been restricted to a limited number of cytosines. Here, we present an oligonucleotide microarray that permits the parallel analysis of the methylation status of individual cytosines, thus combining high throughput and high resolution. The approach was used to study the CpG island in the promoter region of the tumour suppressor gene p16(INK4A). In total, 876 oligonucleotide probes of 21 nt in length were used to inspect the methylation status of 53 CpG dinucleotides, producing correct signals in colorectal cancer cell lines as well as control samples with a defined methylation status. The information was validated by established alternative methods. The overall methylation pattern was consistent for each cell line, while different between them. At the level of individual cytosines, however, significant variations between individual cells of the same type were found, but also consistencies across the panel of cancer cell lines were observed
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