155 research outputs found
Strategic orientation, strategic renewal, and the international performance of born global firms
The international business environment is both dynamic and turbulent. Accordingly, a new ventureâs strategic orientation (SO) and ability to undertake strategic renewal (SR) are of great importance to its survival, growth and international performance. Building on the dynamic capability perspective, we explore how SR capability mediates the relationship between SO and the performance of mature born global firms (BGFs). In particular, we examine the direct and indirect interplay between the SO of BGFs and their performance outcomes. We use a sample of 195 export-oriented BGFs, derived from the Bangladeshi apparel industry. We use a hierarchical regression analysis technique to test the direct effects. The mediation effect is examined using three statistical tests â Baron and Kenneyâs (1986) causal steps approach, the Sobel test, and the Hayes indirect effect with bootstrapping method â to ensure the validity and reliability of our findings. The results reveal a positive association between SO and the performance of BGFs, and that this relationship is mediated by the firmsâ SR capability. We contribute to a greater understanding of the drivers of mature BGFsâ international performance by demonstrating a direct link between their SO and SR capability, which in turn affects their performance outcomes
Screening and characterization of antimicrobial secondary metabolites from Halomonas salifodinae MPM-TC and its in vivo antiviral influence on Indian white shrimp Fenneropenaeus indicus against WSSV challenge
AbstractAntimicrobial secondary metabolites from extremophiles play a significant role in the pharmacological industry due to their stable and strong activity and it is used in the treatment of microbial infections. In the present work, Halomonas salifodinae MPM-TC (M. Peter Marian-T. Citarasu) was isolated from the solar salt works in India and identified by 16S rRNA sequencing. The secondary metabolites were extracted from H. salifodinae MPM-TC and tested for antibacterial activity against aquatic bacterial pathogens such as Vibrio harveyi, Vibrio parahaemolyticus, Pseudomonas aeruginosa and Aeromonas hydrophila isolated from infected fish/shrimp, and it effectively controlled them with more than 10mm of zone of inhibition. The metabolites were purified through silica column chromatography and in vitro antiviral activity was performed against White Spot Syndrome Virus (WSSV) using different fractions. Among the different tested fractions, fraction-III (F-III) was able to suppress WSSV replication. Shrimps challenged with a WSSV inoculum incubated with F-III and treated Fenneropenaeus indicus survived around twice as many as the controls. Gas chromatographyâmass spectroscopic (GCâMS) analysis revealed that the antiviral active fraction contains around eight compounds including Perfluorotributylamine, Cyclopentane, 1-butyl-2-ethyl and 1,1âČ-Biphenyl]-3-amine. Further the active fraction F-III was incorporated in the artificial diets at the concentration of 200 (HS1), 400 (HS2) and 800 (HS3) ÎŒgkgâ1 and fed to F. indicus for 30days. After 30days of culture, shrimps were challenged with virulent WSSV and studied for WSSV VP 28 gene expression, biochemical, haematological and immunological changes. Surprisingly, groups treated with lower concentrations of fraction F-III (HS1 or HS2) significantly (P<0.05) suppressed the viral replication. Different levels of protein and glucose, improved total haemocyte count (THC), coagulase activity and oxyhaemocyanin level all were comparable to controls. Also, immunological parameters such as prophenol oxidase and intracellular superoxide anion production were significantly increased (F=97.18; Pâ©œ0.001 and F=5.70; Pâ©œ0.05) in the groups treated with the three test concentrations. The presence of antiviral and immunostimulant active principles in the F-III fraction effectively suppressed the WSSV load and boosted F. indicusâs immune system. This research will help to develop novel antiviral drugs from plants against aquatic important pathogens
U(2)-like Flavor Symmetries and Approximate Bimaximal Neutrino Mixing
Models involving a U(2) flavor symmetry, or any of a number of its
non-Abelian discrete subgroups, can explain the observed hierarchy of charged
fermion masses and CKM angles. It is known that a large neutrino mixing angle
connecting second and third generation fields may arise via the seesaw
mechanism in these models, without a fine tuning of parameters. Here we show
that it is possible to obtain approximate bimaximal mixing in a class of models
with U(2)-like Yukawa textures. We find a minimal form for Dirac and Majorana
neutrino mass matrices that leads to two large mixing angles, and show that our
result can quantitatively explain atmospheric neutrino oscillations while
accommodating the favored, large angle MSW solution to the solar neutrino
problem. We demonstrate that these textures can arise in models by presenting a
number of explicit examples.Comment: 20 pages RevTex4, 2 figure
Maximal Neutrino Mixing from a Minimal Flavor Symmetry
We study a number of models, based on a non-Abelian discrete group, that
successfully reproduce the simple and predictive Yukawa textures usually
associated with U(2) theories of flavor. These models allow for solutions to
the solar and atmospheric neutrino problems that do not require altering
successful predictions for the charged fermions or introducing sterile
neutrinos. Although Yukawa matrices are hierarchical in the models we consider,
the mixing between second- and third-generation neutrinos is naturally large.
We first present a quantitative analysis of a minimal model proposed in earlier
work, consisting of a global fit to fermion masses and mixing angles, including
the most important renormalization group effects. We then propose two new
variant models: The first reproduces all important features of the SU(5)xU(2)
unified theory with neither SU(5) nor U(2). The second demonstrates that
discrete subgroups of SU(2) can be used in constructing viable supersymmetric
theories of flavor without scalar universality even though SU(2) by itself
cannot.Comment: 34 pages LaTeX, 1 eps figure, minor revisions and references adde
Gauge and Scheme Dependence of Mixing Matrix Renormalization
We revisit the issue of mixing matrix renormalization in theories that
include Dirac or Majorana fermions. We show how a gauge-variant on-shell
renormalized mixing matrix can be related to a manifestly gauge-independent one
within a generalized scheme of renormalization. This
scheme-dependent relation is a consequence of the fact that in any scheme of
renormalization, the gauge-dependent part of the mixing-matrix counterterm is
ultra-violet safe and has a pure dispersive form. Employing the unitarity
properties of the theory, we can successfully utilize the afore-mentioned
scheme-dependent relation to preserve basic global or local symmetries of the
bare Lagrangian through the entire process of renormalization. As an immediate
application of our study, we derive the gauge-independent renormalization-group
equations of mixing matrices in a minimal extension of the Standard Model with
isosinglet neutrinos.Comment: 31 pages, LaTeX, uses axodraw.st
Cold Plus Hot Dark Matter Cosmology in the Light of Solar and Atmospheric Neutrino Oscillations
We explore the implications of possible neutrino oscillations, as indicated
by the solar and atmospheric neutrino experiments, for the cold plus hot dark
matter scenario of large scale structure formation. We find that there are
essentially three distinct schemes that can accommodate the oscillation data
and which also allow for dark matter neutrinos. These include (i) three nearly
degenerate (in mass) neutrinos, (ii) non-degenerate masses with in
the eV range, and (iii) nearly degenerate pair (in the eV
range), with the additional possibility that the electron neutrino is
cosmologically significant. The last two schemes invoke a `sterile' neutrino
which is light (< or ~ eV). We discuss the implications of these schemes for
and oscillation, and find
that scheme (ii) in particular, predicts them to be in the observable range. As
far as structure formation is concerned, we compare the one neutrino flavor
case with a variety of other possibilities, including two and three degenerate
neutrino flavors. We show, both analytically and numerically, the effects of
these neutrino mass scenarios on the amplitude of cosmological density
fluctuations. With a Hubble constant of 50 km s Mpc, a spectral
index of unity, and , the two and three flavor
scenarios fit the observational data marginally better than the single flavor
scheme. However, taking account of the uncertainties in these parameters, we
show that it is premature to pick a clear winner.Comment: 1 LaTEX file plus 1 uuencoded Z-compressed tar file with 3 postscript
figure
Updated Reach of the CERN LHC and Constraints from Relic Density, b->s gamma and a(mu) in the mSUGRA Model
{We present an updated assessment of the reach of the CERN LHC pp collider
for supersymmetric matter in the context of the minimal supergravity (mSUGRA)
model. In addition to previously examined channels, we also include signals
with an isolated photon or with a leptonically decaying Z boson. For an
integrated luminosity of 100 fb^{-1}, values of m_{1/2}\sim 1400 GeV can be
probed for small m_0, corresponding to a gluino mass of m_{\tg}\sim 3 TeV. For
large m_0, in the hyperbolic branch/focus point region, m_{1/2}\sim 700 GeV can
be probed, corresponding to m_{\tg}\sim 1800 GeV. We also map out parameter
space regions preferred by the measured values of the dark matter relic
density, the b\to s\gamma decay rate, and the muon anomalous magnetic moment
a_\mu, and discuss how SUSY might reveal itself in these regions. We find the
CERN LHC can probe the entire stau co-annihilation region and also most of the
heavy Higgs annihilation funnel allowed by WMAP data, except for some range of
large m_0 and m_{1/2} if \tan\beta \agt 50.Comment: 22 page latex file including 10 EPS figures; bug fix in relic density
code modifies figures in co-annihilation regio
Collider aspects of flavour physics at high Q
This review presents flavour related issues in the production and decays of
heavy states at LHC, both from the experimental side and from the theoretical
side. We review top quark physics and discuss flavour aspects of several
extensions of the Standard Model, such as supersymmetry, little Higgs model or
models with extra dimensions. This includes discovery aspects as well as
measurement of several properties of these heavy states. We also present public
available computational tools related to this topic.Comment: Report of Working Group 1 of the CERN Workshop ``Flavour in the era
of the LHC'', Geneva, Switzerland, November 2005 -- March 200
Lipolysis drives expression of the constitutively active receptor GPR3 to induce adipose thermogenesis
Thermogenic adipocytes possess a therapeutically appealing, energy-expending capacity, which is canonically cold-induced by ligand-dependent activation of beta-adrenergic G protein-coupled receptors (GPCRs). Here, we uncover an alternate paradigm of GPCR-mediated adipose thermogenesis through the constitutively active receptor, GPR3. We show that the N terminus of GPR3 confers intrinsic signaling activity, resulting in continuous Gscoupling and cAMP production without an exogenous ligand. Thus, transcriptional induction of Gpr3 represents the regulatory parallel to ligand-binding of conventional GPCRs. Consequently, increasing Gpr3 expression in thermogenic adipocytes is alone sufficient to drive energy expenditure and counteract metabolic disease in mice. Gpr3 transcription is cold-stimulated by a lipolytic signal, and dietary fat potentiates GPR3-dependent thermogenesis to amplify the response to caloric excess. Moreover, we find GPR3 to be an essential, adrenergic-independent regulator of human brown adipocytes. Taken together, our findings reveal a noncanonical mechanism of GPCR control and thermogenic activation through the lipolysis-induced expression of constitutively active GPR3.Diabetes mellitus: pathophysiological changes and therap
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