The diversity of why: a meta-analytical study of usage motivation in enterprise social networks

In times of demographic change, skill shortage and disruptive innovations, organizational knowledge management and innovative capacity are the key to a company’s success. But how can knowledge be retained with fast staff turnover, global project-based work and parental leaves? Using enterprise social media to improve knowledge dissemination at work seems promising, when looking at the success of private social networking sites. In this article we combine ten different empirical studies which investigated different aspects of how user diversity influences the motivation to use social media at work. The emerging meta-study using the DerSimonian–Laird method (total sample size \(N=522\)) analyzes different aspects of user diversity and their correlation with eight motives for SNS usage: information, importance, contact, self-presentation, autonomy, social comparison, and power and control. We found that that the individual achievement motivation correlates positively with the motives importance, power, information and self-presentation. The need for autonomy correlates with openness to new experiences and the need for social comparison with gender and neuroticism. From our findings, we derive practical implications for designing a social networking site for work which fulfills the users’ needs and functions along their motivation.     

DNA‐SMART: Biopatterned Polymer Film Microchannels for Selective Immobilization of Proteins and Cells

A novel SMART module, dubbed “DNA‐SMART” (DNA substrate modification and replication by thermoforming) is reported, where polymer films are premodified with single‐stranded DNA capture strands, microthermoformed into 3D structures, and postmodified with complementary DNA‐protein conjugates to realize complex biologically active surfaces within microfluidic devices. As a proof of feasibility, it is demonstrated that microchannels presenting three different proteins on their inner curvilinear surface can be used for selective capture of cells under flow conditions.     

The “<Emphasis Type="Italic">Daphnia</Emphasis>” Lynx Mark I Suborbital Flight Experiment: Hardware Qualification at the Drop Tower Bremen

The Drop Tower Bremen, a ground-based facility enabling research under real microgravity conditions, is an excellent platform for testing new types of experimental hardware to ensure full performance when deployed in costly and rare flight opportunities such as suborbital flights. Here we describe the “Daphnia” experiment which will fly on XCOR Aerospace Lynx Mark I and our experience from the hardware tests with the catapult system at the drop tower. The aim of the “Daphnia” experiment is to obtain data on the biological performance of daphnids and predator-prey interactions in microgravity, which are important for the development of aquatic bioregenerative life support systems (BLSS). The experiment consists of two subunits: The first unit is dedicated to predator-prey interactions, where behavioural analysis should reveal if microgravity interfere with prey (Daphnia) detection or feeding and therefore may interrupt the trophic cascade. The functioning of such an artificial food web is indispensable for a long-lasting BLSS suitable for long-duration manned space missions or Earth-based explorations to extreme habitats. The second unit is designed to investigate the impact of microgravity on gene expression and the cytoskeleton in Daphnia. Next to data collection, the real microgravity conditions at the drop tower have helped to identify the weak points of the “Daphnia” experimental hardware and lead to further improvement. Hence, the drop tower is ideal for testing new experimental hardware which is indispensable before the implementation in suborbital flights.     

Responses of Microcrustaceans to Simulated Microgravity (2D-Clinorotation) - Preliminary Assessments for the Development of Bioregenerative Life Support Systems (BLSS)

Bioregenerative Life Support Systems (BLSS) are an endeavor to create environments able to maintain human life e.g. on future long-duration space missions like flights to Mars. Based on cyclic biological processes, these systems will be independent from material resupply (such as food, water and oxygen). Due to their central role in limnic ecosystems, herbivorous microcrustaceans could act as key player in aquatic BLSS as they link oxygen liberating, autotrophic producers like algae to higher trophic levels, such as fish. However, before such BLSS can be utilized in space, organisms inhabiting these systems have to be studied thoroughly to disclose the gravitational impact on the biological processes. This is possible in real microgravity, but requires high financial resources, is opportunity-limited or periods of microgravity are very short. Yet, cost-effective and almost permanently accessible tools for gravitational research are ground-based facilities (GBFs), providing simulated microgravity. Among those GBFs is the so called 2D-clinostat. In the present study we demonstrate, that rotation of clinostat tubes does not generate acceleration in form of (predator resembling) small scale turbulence, which can be perceived by Daphnia cucullata. Additionally, embryonal development is not disturbed in subitaneous eggs of Daphnia magna and resting eggs of the ostracod Heterocypris incongruens (besides through restrictions in space within the narrow clinostat tubes), just as subsequent hatching from the respective eggs. Hence, our results indicate that clinorotation is a suitable method to simulate microgravity for microcrustaceans.     

Ammonia Released by <Emphasis Type="Italic">Streptomyces aburaviensis</Emphasis> Induces Droplet Formation in <Emphasis Type="Italic">Streptomyces violaceoruber</Emphasis>

Streptomyces violaceoruber grown in co-culture with Streptomyces aburaviensis produces an about 17-fold higher volume of droplets on its aerial mycelium than in single-culture. Physical separation of the Streptomyces strains by either a plastic barrier or by a dialysis membrane, which allowed communication only by the exchange of volatile compounds or diffusible compounds in the medium, respectively, still resulted in enhanced droplet formation. The application of molecular sieves to bioassays resulted in the attenuation of the droplet-inducing effect of S. aburaviensis indicating the absorption of the compound. ¹H-NMR analysis of molecular-sieve extracts and the selective indophenol-blue reaction revealed that the volatile droplet-inducing compound is ammonia. The external supply of ammonia in biologically relevant concentrations of ≥8 mM enhanced droplet formation in S. violaceoruber in a similar way to S. aburaviensis. Ammonia appears to trigger droplet production in many Streptomyces strains because four out of six Streptomyces strains exposed to ammonia exhibited induced droplet production.     

Phenotypic and genetic relationships between age at first calving,its component traits,and survival of heifers up to second calving

The aim of this study was to answer the question whether models for genetic evaluations of longevity should include a correction for age at first calving (AFC). For this purpose, phenotypic and genetic relationships between AFC, its component traits age at first insemination (AFI) and interval from first to last insemination (FLI), and survival of different periods of the first lactation (S1: 0 to 49 d, S2: 50 to 249 d, S3: 250 d to second calving) were investigated. Data of 721,919 German Holstein heifers, being inseminated for the first time during the years from 2003 to 2012, were used for the analyses. Phenotypic correlations of AFI, FLI, and AFC to S1 to S3 were negative. Mean estimated heritabilities were 0.239 (AFI), 0.007 (FLI), and 0.103 (AFC) and 0.023 (S1), 0.016 (S2), and 0.028 (S3) on the observed scale. The genetic correlation between AFI and FLI was close to zero. Genetic correlations between AFI and the survival traits were ?0.08 (S1), ?0.02 (S2), and ?0.10 (S3); those between FLI and the survival traits were ?0.14 (S1), ?0.20 (S2), and ?0.44 (S3); and those between AFC and the survival traits were ?0.09 (S1), ?0.06 (S2), and ?0.20 (S3). Some of these genetic correlations were different from zero, which suggests that correcting for AFC in genetic evaluations for longevity in dairy cows might remove functional genetic variance and should be reconsidered.     

Determination of optimum imaging conditions in AC-SECM using the mathematical distance between approach curves displayed in the impedance domain

Scanning electrochemical microscopy (SECM) in its alternating current mode (AC-SECM) has been of growing importance to detect and interpret local variations of electrochemical surface properties with high spatial resolution. The sensitivity of AC-SECM and hence the quality of imaging was found to be highly dependent on the experimental conditions. It was commonly judged using approach curves in the distance domain. As an alternative to current-distance approach curves, the coordinate system based on real and imaginary part of impedance is suggested for their display. In this framework, the difference between the impedance vector magnitude, real or imaginary part of impedance over neighboring surfaces is considered as a measure of imaging contrast. The variable which grants maximum difference is selected for imaging while measurement conditions associated with this maximum indicate optimum scanning conditions. The methodology of determining these optimized parameters is laid out in this contribution and examples are given. Since the optimum parameters are identified before the actual lateral imaging, this time-saving method facilitates the visualization of local electrochemical properties at the highest possible quality.