492 research outputs found
Coevolution of Firm Capabilities and Industry Competition
This paper proposes that rival firms not only search for new capabilities within their organization, but also for those that rest in their competitive environment. An integrated analysis of these search processes at both firm and industry levels of analysis shows how their interaction makes industries and firms coevolve over time. To contribute to an enhanced understanding of the concept of coevolution, a dynamic and integrative framework crossing meso and micro levels of analysis is constructed. This framework is applied to a longitudinal study of the music industry with a time-span of 120 years. The first part, a historical study, covers the period 1877 - 1990. The second part, a multiple-case study, covers the period 1990 - 1997. We conclude that search behavior drives coevolution through competitive dynamics among new entrants and incumbent firms and manifests itself in the simultaneous emergence of new business models and new organizational forms
Jun N-terminal kinase 1 regulates epithelial-to-mesenchymal transition induced by TGF-beta1
Transforming growth factor beta1 (TGF-beta1) is a cardinal cytokine in the pathogenesis of airway remodeling, and promotes epithelial-to-mesenchymal transition (EMT). As a molecular interaction between TGF-beta1 and Jun N-terminal kinase (JNK) has been demonstrated, the goal of this study was to elucidate whether JNK plays a role in TGF-beta1-induced EMT. Primary cultures of mouse tracheal epithelial cells (MTEC) from wild-type, JNK1-/- or JNK2-/- mice were comparatively evaluated for their ability to undergo EMT in response to TGF-beta1. Wild-type MTEC exposed to TGF-beta1 demonstrated a prominent induction of mesenchymal mediators and a loss of epithelial markers, in conjunction with a loss of trans-epithelial resistance (TER). Significantly, TGF-beta1-mediated EMT was markedly blunted in epithelial cells lacking JNK1, while JNK2-/- MTEC underwent EMT in response to TGF-beta1 in a similar way to wild-type cells. Although Smad2/3 phosphorylation and nuclear localization of Smad4 were similar in JNK1-/- MTEC in response to TGF-beta1, Smad DNA-binding activity was diminished. Gene expression profiling demonstrated a global suppression of TGF-beta1-modulated genes, including regulators of EMT in JNK1-/- MTEC, in comparison with wild-type cells. In aggregate, these results illuminate the novel role of airway epithelial-dependent JNK1 activation in EMT
Coronal Temperature Diagnostic Capability of the Hinode/X-Ray Telescope Based on Self-Consistent Calibration
The X-Ray Telescope (XRT) onboard the Hinode satellite is an X-ray imager
that observes the solar corona with unprecedentedly high angular resolution
(consistent with its 1" pixel size). XRT has nine X-ray analysis filters with
different temperature responses. One of the most significant scientific
features of this telescope is its capability of diagnosing coronal temperatures
from less than 1 MK to more than 10 MK, which has never been accomplished
before. To make full use of this capability, accurate calibration of the
coronal temperature response of XRT is indispensable and is presented in this
article. The effect of on-orbit contamination is also taken into account in the
calibration. On the basis of our calibration results, we review the
coronal-temperature-diagnostic capability of XRT
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Implementing a Sleep Health Education and Sleep Disorders Screening Program in Fire Departments: A Comparison of Methodology
Objective: The objective of this study is to compare three methods of administering a sleep health program (SHP) in fire departments. Methods: An SHP, comprising sleep health education and screening for common sleep disorders, was implemented in eight fire departments using three approaches: expert-led, train-the-trainer, and online. Participation rates, knowledge assessments, surveys, and focus group interviews were analyzed to assess the reach and effectiveness of the methodologies. Results: The Expert-led SHP had the highest participation rate, greatest improvement in knowledge scores, and prompted more firefighters to seek clinical sleep disorder evaluations (41%) than the other approaches (20 to 25%). Forty-two percent of focus group participants reported changing their sleep behaviors. Conclusion: All approaches yielded reasonable participation rates, but expert-led programs had the greatest reach and effectiveness in educating and screening firefighters for sleep disorders
A priori collaboration in population imaging: The Uniform Neuro-Imaging of Virchow-Robin Spaces Enlargement consortium
Introduction: Virchow-Robin spaces (VRS), or perivascular spaces, are compartments of interstitial fluid enclosing cerebral blood vessels and are potential imaging markers of various underlying brain pathologies. Despite a growing interest in the study of enlarged VRS, the heterogeneity in rating and quantification methods combined with small sample sizes have so far hampered advancement in the field. Methods: The Uniform Neuro-Imaging of Virchow-Robin Spaces Enlargement (UNIVRSE) consortium was established with primary aims to harmonize rating and analysis (www.uconsortium.org). The UNIVRSE consortium brings together 13 (sub)cohorts from five countries, totaling 16,000 subjects and over 25,000 scans. Eight different magnetic resonance imaging protocols were used in the consortium. Results: VRS rating was harmonized using a validated protocol that was developed by the two founding members, with high reliability independent of scanner type, rater experience, or concomitant brain pathology. Initial analyses revealed risk factors for enlarged VRS including increased age, sex, high blood pressure, brain infarcts, and white matter lesions, but this varied by brain region. Discussion: Early collaborative efforts between cohort studies with respect to data harmonization and joint analyses can advance the field of population (neuro)imaging. The UNIVRSE consortium will focus efforts on other potential correlates of enlarged VRS, including genetics, cognition, stroke, and dementia
Energy Flow in the Hadronic Final State of Diffractive and Non-Diffractive Deep-Inelastic Scattering at HERA
An investigation of the hadronic final state in diffractive and
non--diffractive deep--inelastic electron--proton scattering at HERA is
presented, where diffractive data are selected experimentally by demanding a
large gap in pseudo --rapidity around the proton remnant direction. The
transverse energy flow in the hadronic final state is evaluated using a set of
estimators which quantify topological properties. Using available Monte Carlo
QCD calculations, it is demonstrated that the final state in diffractive DIS
exhibits the features expected if the interaction is interpreted as the
scattering of an electron off a current quark with associated effects of
perturbative QCD. A model in which deep--inelastic diffraction is taken to be
the exchange of a pomeron with partonic structure is found to reproduce the
measurements well. Models for deep--inelastic scattering, in which a
sizeable diffractive contribution is present because of non--perturbative
effects in the production of the hadronic final state, reproduce the general
tendencies of the data but in all give a worse description.Comment: 22 pages, latex, 6 Figures appended as uuencoded fil
Measurement of the p-pbar -> Wgamma + X cross section at sqrt(s) = 1.96 TeV and WWgamma anomalous coupling limits
The WWgamma triple gauge boson coupling parameters are studied using p-pbar
-> l nu gamma + X (l = e,mu) events at sqrt(s) = 1.96 TeV. The data were
collected with the DO detector from an integrated luminosity of 162 pb^{-1}
delivered by the Fermilab Tevatron Collider. The cross section times branching
fraction for p-pbar -> W(gamma) + X -> l nu gamma + X with E_T^{gamma} > 8 GeV
and Delta R_{l gamma} > 0.7 is 14.8 +/- 1.6 (stat) +/- 1.0 (syst) +/- 1.0 (lum)
pb. The one-dimensional 95% confidence level limits on anomalous couplings are
-0.88 < Delta kappa_{gamma} < 0.96 and -0.20 < lambda_{gamma} < 0.20.Comment: Submitted to Phys. Rev. D Rapid Communication
Measurement of the ttbar Production Cross Section in ppbar Collisions at sqrt{s} = 1.96 TeV using Kinematic Characteristics of Lepton + Jets Events
We present a measurement of the top quark pair ttbar production cross section
in ppbar collisions at a center-of-mass energy of 1.96 TeV using 230 pb**{-1}
of data collected by the DO detector at the Fermilab Tevatron Collider. We
select events with one charged lepton (electron or muon), large missing
transverse energy, and at least four jets, and extract the ttbar content of the
sample based on the kinematic characteristics of the events. For a top quark
mass of 175 GeV, we measure sigma(ttbar) = 6.7 {+1.4-1.3} (stat) {+1.6- 1.1}
(syst) +/-0.4 (lumi) pb, in good agreement with the standard model prediction.Comment: submitted to Phys.Rev.Let
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