2,105 research outputs found

    An investigation of the acquisition and sharing of tacit knowledge in software development teams

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    Knowledge in general, and tacit knowledge in particular, has been hailed as an important factor for successful performance in knowledge-worker teams. Despite claims of the importance of tacit knowledge, few researchers have studied the concept empirically, due in part to the confusion surrounding its conceptualisation. The present study examined the acquisition and sharing o f tacit knowledge and the consequent effect on team performance, through social interaction and the development of a transactive memory system (TMS). TMSs are important for the acquisition and sharing of tacit knowledge, since they enact ‘collective minds’ of teams, and are also a factor in successful team performance. In order to conduct this research, a team-level operational definition of tacit knowledge was forwarded and a direct measure of tacit knowledge for software development teams, called the Team Tacit Knowledge Measure (TTKM ) was developed and validated. To investigate the main premise of this research an empirical survey study was conducted which involved 48 software development teams (n = 181 individuals), from Ireland and the UK. Software developers were chosen as the example of knowledge-worker teams because they work with intangible cognitive processes. It was concluded that tacit knowledge was acquired and shared directly through good quality social interactions and through the development of a TMS. Quality of social interaction was found to be a more important route through which teams can learn and share tacit knowledge, than was transactive memory. However, transactive memory was not a mediator between social interaction and team tacit knowledge, indicating that both provided separate contributions. Team tacit knowledge was found to predict team performance above and beyond transactive memory, though both were significant. Based on these findings recommendations were made for the management of software development teams and for future research directions

    Acquiring and sharing tacit knowledge in software development teams: An empirical study

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    Context: Sharing expert knowledge is a key process in developing software products. Since expert knowledge is mostly tacit, the acquisition and sharing of tacit knowledge along with the development of a transactive memory system (TMS) are significant factors in effective software teams. Objective: We seek to enhance our understanding human factors in the software development process and provide support for the agile approach, particularly in its advocacy of social interaction, by answering two questions: How do software development teams acquire and share tacit knowledge? What roles do tacit knowledge and transactive memory play in successful team performance? Method: A theoretical model describing the process for acquiring and sharing tacit knowledge and development of a TMS through social interaction is presented and a second predictive model addresses the two research questions above. The elements of the predictive model and other demographic variables were incorporated into a larger online survey for software development teams, completed by 46 software SMEs, consisting of 181 individual team members. Results: Our results show that team tacit knowledge is acquired and shared directly through good quality social interactions and through the development of a TMS with quality of social interaction playing a greater role than transactive memory. Both TMS and team tacit knowledge predict effectiveness but not efficiency in software teams. Conclusion: It is concluded that TMS and team tacit knowledge can differentiate between low- and high-performing teams in terms of effectiveness, where more effective teams have a competitive advantage in developing new products and bringing them to market. As face-to-face social interaction is key, collocated, functionally rich, domain expert teams are advocated rather than distributed teams, though arguably the team manager may be in a separate geographic location provided that there is frequent communication and effective use of issue tracking tools as in agile teams

    Cholinergic Modulation of Locomotion and Striatal Dopamine Release Is Mediated by α6α4* Nicotinic Acetylcholine Receptors

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    Dopamine (DA) release in striatum is governed by firing rates of midbrain DA neurons, striatal cholinergic tone, and nicotinic ACh receptors (nAChRs) on DA presynaptic terminals. DA neurons selectively express α6* nAChRs, which show high ACh and nicotine sensitivity. To help identify nAChR subtypes that control DA transmission, we studied transgenic mice expressing hypersensitive α6^(L9’S*) receptors. α6^(L9’S) mice are hyperactive, travel greater distance, exhibit increased ambulatory behaviors such as walking, turning, and rearing, and show decreased pausing, hanging, drinking, and grooming. These effects were mediated by α6 α4* pentamers, as α6^(L9’S) mice lacking α4 subunits displayed essentially normal behavior. In α6^(L9’S) mice, receptor numbers are normal, but loss of α4 subunits leads to fewer and less sensitive α6* receptors. Gain-of-function nicotine-stimulated DA release from striatal synaptosomes requires α4 subunits, implicating α6α4β2* nAChRs in α6^(L9’S) mouse behaviors. In brain slices, we applied electrochemical measurements to study control of DA release by α6^(L9’S) nAChRs. Burst stimulation of DA fibers elicited increased DA release relative to single action potentials selectively in α6^(L9’S), but not WT or α4KO/ α6^(L9’S), mice. Thus, increased nAChR activity, like decreased activity, leads to enhanced extracellular DA release during phasic firing. Bursts may directly enhance DA release from α6^(L9’S) presynaptic terminals, as there was no difference in striatal DA receptor numbers or DA transporter levels or function in vitro. These results implicate α6α4β2* nAChRs in cholinergic control of DA transmission, and strongly suggest that these receptors are candidate drug targets for disorders involving the DA system

    Adenovirus serotype 5 E1A sensitizes tumor cells to NKG2D-dependent NK cell lysis and tumor rejection

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    The expression of the Adenovirus serotype 5 (Ad5) E1A oncogene sensitizes tumor cells to natural killer (NK) cell–mediated killing and tumor rejection in vivo. These effects are dependent on the ability of E1A to bind the transcriptional coadaptor protein p300. To test the hypothesis that E1A up-regulates ligands recognized by the NKG2D-activating receptor, we stably transfected the highly tumorigenic mouse fibrosarcoma cell line MCA-205 with Ad5-E1A or a mutant form of E1A that does not interact with p300 (E1A-Δp300). Ad5-E1A, but not E1A-Δp300, up-regulated the expression of the NKG2D ligand retinoic acid early inducible (RAE)-1, but not murine ULBP-like transcript 1, another NKG2D ligand, in four independently derived MCA-205 transfectants. The up-regulation of RAE-1 by E1A targeted MCA-205 tumor cells to lysis by NK cells, resulting in NKG2D-dependent tumor rejection in vivo. Moreover, the up-regulation of NKG2D ligands by E1A was not limited to mouse tumor cells, as E1A also increased the expression of NKG2D ligands on primary baby mouse kidney cells, human MB435S breast cancer cells, and human H4 fibrosarcoma cells

    6.3 DOUGLAS-FIR BEETLE ATTACK AND TREE MORTALITY FOLLOWING WILDFIRE

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    ABSTRACT A major concern after wildfires is the buildup of bark beetle populations in fire injured trees, and subsequent attack and population buildup in adjacent unburned areas. To examine this concern, we documented fire injury and insect attacks in Douglas-fir (Pseudotsuga menziesii) on the 2001 Green Knoll Fire, Wyoming to determine attack preferences, brood production, and emergence densities in different levels of fireinjured trees. Tree injuries of crown scorch, ground char, bole char, and basal girdling were recorded in mixed-severity burn areas. Douglas fir beetle (Dendroctonus pseudotsugae) attack densities and brood production were sampled on two sides of infested trees in the fall of 2002. Sampled trees were organized into different combinations of crown scorch and basal girdling. Cages (1x2 ft) were installed on a subsample of trees in each category in spring of 2003 to sample beetle emergence densities. Crown scorch, prefire vigor, dbh, and the interaction of crown scorch and basal girdling were significant variables in explaining whether a tree was attacked by Douglas fir beetle. The number of brood sampled in fall was significantly affected by the percent crown scorch but not the percent basal girdling; however, the emergence the following spring was not significantly correlated with either crown scorch or basal girdling. Further analyses of attack and tree injury correlations are planned

    Supernovae in the Subaru Deep Field: An Initial Sample, and Type Ia Rate, out to Redshift 1.6

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    Large samples of high-redshift supernovae (SNe) are potentially powerful probes of cosmic star formation, metal enrichment, and SN physics. We present initial results from a new deep SN survey, based on re-imaging in the R, i', z' bands, of the 0.25 deg2 Subaru Deep Field (SDF), with the 8.2-m Subaru telescope and Suprime-Cam. In a single new epoch consisting of two nights of observations, we have discovered 33 candidate SNe, down to a z'-band magnitude of 26.3 (AB). We have measured the photometric redshifts of the SN host galaxies, obtained Keck spectroscopic redshifts for 17 of the host galaxies, and classified the SNe using the Bayesian photometric algorithm of Poznanski et al. (2007) that relies on template matching. After correcting for biases in the classification, 55% of our sample consists of Type Ia supernovae and 45% of core-collapse SNe. The redshift distribution of the SNe Ia reaches z ~ 1.6, with a median of z ~ 1.2. The core-collapse SNe reach z ~ 1.0, with a median of z ~ 0.5. Our SN sample is comparable to the Hubble Space Telescope/GOODS sample both in size and redshift range. The redshift distributions of the SNe in the SDF and in GOODS are consistent, but there is a trend (which requires confirmation using a larger sample) for more high-z SNe Ia in the SDF. This trend is also apparent when comparing the SN Ia rates we derive to those based on GOODS data. Our results suggest a fairly constant rate at high redshift that could be tracking the star-formation rate. Additional epochs on this field, already being obtained, will enlarge our SN sample to the hundreds, and determine whether or not there is a decline in the SN Ia rate at z >~ 1.Comment: 20 pages, 8 figures, MNRAS accepte

    Web-based data collection: detailed methods of a questionnaire and data gathering tool

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    There have been dramatic advances in the development of web-based data collection instruments. This paper outlines a systematic web-based approach to facilitate this process through locally developed code and to describe the results of using this process after two years of data collection. We provide a detailed example of a web-based method that we developed for a study in Starr County, Texas, assessing high school students' work and health status. This web-based application includes data instrument design, data entry and management, and data tables needed to store the results that attempt to maximize the advantages of this data collection method. The software also efficiently produces a coding manual, web-based statistical summary and crosstab reports, as well as input templates for use by statistical packages. Overall, web-based data entry using a dynamic approach proved to be a very efficient and effective data collection system. This data collection method expedited data processing and analysis and eliminated the need for cumbersome and expensive transfer and tracking of forms, data entry, and verification. The code has been made available for non-profit use only to the public health research community as a free download [1]

    RCS2 J232727.6-020437: An Efficient Cosmic Telescope at z=0.6986z=0.6986

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    We present a detailed gravitational lens model of the galaxy cluster RCS2 J232727.6-020437. Due to cosmological dimming of cluster members and ICL, its high redshift (z=0.6986z=0.6986) makes it ideal for studying background galaxies. Using new ACS and WFC3/IR HST data, we identify 16 multiple images. From MOSFIRE follow up, we identify a strong emission line in the spectrum of one multiple image, likely confirming the redshift of that system to z=2.083z=2.083. With a highly magnified (μ2\mu\gtrsim2) source plane area of 0.7\sim0.7 arcmin2^2 at z=7z=7, RCS2 J232727.6-020437 has a lensing efficiency comparable to the Hubble Frontier Fields clusters. We discover four highly magnified z7z\sim7 candidate Lyman-break galaxies behind the cluster, one of which may be multiply-imaged. Correcting for magnification, we find that all four galaxies are fainter than 0.5L0.5 L_{\star}. One candidate is detected at >10σ{>10\sigma} in both Spitzer/IRAC [3.6] and [4.5] channels. A spectroscopic follow-up with MOSFIRE does not result in the detection of the Lyman-alpha emission line from any of the four candidates. From the MOSFIRE spectra we place median upper limits on the Lyman-alpha flux of 514×1019ergs1cm25-14 \times 10^{-19}\, \mathrm{erg \,\, s^{-1} cm^{-2}} (5σ5\sigma).Comment: 14 pages, 9 figures, submitted to ApJ on 3/06/201
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