2,513 research outputs found
New Product Development and Product Supply Within a Network Setting: The Case of the Chilled Ready-Meal Industry in the UK
This paper analyses inter-organizational networks that link together firms operating in the food processing and distribution industry in the UK. In doing so, the paper draws on insights recently developed by Mark Casson that treat inter-firm networks as an institutional response to the changing costs and opportunities of information management. Detailed analysis of product innovation and supply chain management issues within the industry, exemplified by the growth of chilled ready-meals, leads to the identification of two distinct but complementary inter-firm networks: a network of control and a network of innovation. In each case, the study finds that the critical information is derived from the retailers’ interface with consumers and thus that these information-based networks are effectively controlled by the leading supermarket chains. The study’s conclusions are considered in relation to the recent findings of the Competition Commission following its investigation into grocery retailing in the UK
Interferon-γ induces immunoproteasomes and the presentation of MHC I-associated peptides on human salivary gland cells.
A prominent histopathological feature of Sjögren's syndrome, an autoimmune disease, is the presence of lymphocytic infiltrates in the salivary and lachrymal glands. Such infiltrates are comprised of activated lymphocytes and macrophages, and known to produce multiple cytokines including interferon-gamma (IFN-γ). In this study, we have demonstrated that IFN-γ strongly induces the expression of immunoproteasome beta subunits (β1i, β2i and β5i) and immunoproteasome activity but conversely inhibits the expression of proteasome beta subunits (β1, β2 and β5) in human salivary gland (HSG) cells. Mass spectrometric analysis has revealed potential MHC I-associated peptides on the HSG cells, including a tryptic peptide derived from salivary amylase, due to IFN-γ stimulation. These results suggest that IFN-γ induces immunoproteasomes in HSG cells, leading to enhanced presentation of MHC I-associated peptides on cell surface. These peptide-presenting salivary gland cells may be recognized and targeted by auto-reactive T lymphocytes. We have also found that lactacystin, a proteasome inhibitor, inhibits the expression of β1 subunit in HSG cells and blocks the IFN-γ-induced expression of β1i and immunoproteasome activity. However, the expression of β2i and β5i in HSG cells is not affected by lactacystin. These results may add new insight into the mechanism regarding how lactacystin blocks the action of proteasomes or immunoproteasomes
Simulating stellar winds in AMUSE
We present stellar_wind.py, a module that provides multiple methods of
simulating stellar winds using smoothed particle hydrodynamics codes (SPH)
within the astrophysical multipurpose software environment (AMUSE) framework.
With the simple wind mode, we create SPH wind particles in a spherically
symmetric shell. We inject the wind particles with a velocity equal to their
terminal velocity. The accelerating wind mode is similar, but with this method
particles can be injected with a lower initial velocity than the terminal
velocity and they are accelerated away from the star according to an
acceleration function. With the heating wind mode, SPH particles are created
with zero initial velocity with respect to the star, but instead wind particles
are given an internal energy based on the integrated mechanical luminosity of
the star. This mode is designed to be used on longer timescales and larger
spatial scales compared to the other two modes and assumes that the star is
embedded in a gas cloud. For fast winds, we find that both the simple and
accelerating mode can reproduce the desired velocity, density and temperature
profiles. For slow winds, the simple wind mode is insufficient due to dominant
hydrodynamical effects that change the wind velocities. The accelerating mode,
with additional options to account for these hydrodynamical effects, can still
reproduce the desired wind profiles. We test the heating mode by simulating
both a normal wind and a supernova explosion of a single star in a uniform
density medium. The stellar wind simulation results matches the analytical
solution for an expanding wind bubble. The supernova simulation gives
qualitatively correct results, but the simulated bubble expands faster than the
analytical solution predicts. We conclude with an example of a triple star
system which includes the colliding winds of all three stars.Comment: Accepted for publication in A&
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Aversion and attraction to harmful plant secondary compounds jointly shape the foraging ecology of a specialist herbivore.
Most herbivorous insect species are restricted to a narrow taxonomic range of host plant species. Herbivore species that feed on mustard plants and their relatives in the Brassicales have evolved highly efficient detoxification mechanisms that actually prevent toxic mustard oils from forming in the bodies of the animals. However, these mechanisms likely were not present during the initial stages of specialization on mustard plants ~100 million years ago. The herbivorous fly Scaptomyza nigrita (Drosophilidae) is a specialist on a single mustard species, bittercress (Cardamine cordifolia; Brassicaceae) and is in a fly lineage that evolved to feed on mustards only in the past 10-20 million years. In contrast to many mustard specialists, S. nigrita does not prevent formation of toxic breakdown products (mustard oils) arising from glucosinolates (GLS), the primary defensive compounds in mustard plants. Therefore, it is an appealing model for dissecting the early stages of host specialization. Because mustard oils actually form in the bodies of S. nigrita, we hypothesized that in lieu of a specialized detoxification mechanism, S. nigrita may mitigate exposure to high GLS levels within plant tissues using behavioral avoidance. Here, we report that jasmonic acid (JA) treatment increased GLS biosynthesis in bittercress, repelled adult female flies, and reduced larval growth. S. nigrita larval damage also induced foliar GLS, especially in apical leaves, which correspondingly displayed the least S. nigrita damage in controlled feeding trials and field surveys. Paradoxically, flies preferred to feed and oviposit on GLS-producing Arabidopsis thaliana despite larvae performing worse in these plants versus non-GLS-producing mutants. GLS may be feeding cues for S. nigrita despite their deterrent and defensive properties, which underscores the diverse relationship a mustard specialist has with its host when lacking a specialized means of mustard oil detoxification
Treatment Initiation, Program Attrition and Patient Treatment Outcomes associated with Scale-up and Decentralization of HIV care in rural Malawi
To describe patient antiretroviral therapy (cART) outcomes associated with intensive decentralization of services in a rural HIV program in Malawi
Treatment Initiation, Program Attrition and Patient Treatment Outcomes associated with Scale-up and Decentralization of HIV care in rural Malawi
To describe patient antiretroviral therapy (cART) outcomes associated with intensive decentralization of services in a rural HIV program in Malawi
Meteoroid and debris special investigation group data acquisition procedures
The entire LDEF spacecraft was examined by M&D SIG for impact (i.e., craters greater than or = 0.5 mm and penetrations greater than or = 0.3 mm in diameter) and related features (e.g., debris, secondaries). During the various detailed surveys conducted at NASA Kennedy, approx. 5,000 impact related features were photodocumented, and their locations measured and recorded; an additional approx. 30,000 smaller features were counted. The equipment and techniques used by the M&D SIG permitted the determination and recording of the locations and diameters of the 5,000 imaged features. A variety of experimental and LDEF structural hardware was acquired by the M&D SIG and is presently being examined and curated at NASA Johnson
Diversité fonctionnelle: Nécessité d'évaluer la réponse écologique des assemblages de poissons de récif à une perturbation des stratégies de protection
Developing and evaluating process-oriented metrics, such as functional trait diversity metrics, is a high priority to assess the ecological responses of reef fish communities to disturbances and for adaptive ecosystem-based management in marine protected areas (MPAs). We applied five functional diversity metrics (functional entities, redundancy, richness, dispersion, and evenness) to fish assemblage data from an 11-year monitoring dataset of coral reefs in the U.S. Virgin Islands to assess: 1) the spatio-temporal variance in the trophic function of fish communities before, during and after a mass coral bleaching event in 2005; and 2) the association of fish functional diversity with benthic composition, diversity, and structure of reefs inside and outside of No-Take and Multiple Use MPAs. The lack of spatial variation in fish functional diversity metrics suggested no MPA effects during the evaluated time. After the coral bleaching event in 2005, the number of fish functional entities, functional richness, and variation (dispersion) declined inside a No-Take MPA in St. Croix, failing to return to pre-disturbance values over the subsequent seven years. Reefs with high topographic complexity and hard coral species richness supported high richness and redundancy of functional roles. We concluded that functional diversity metrics based on the trophic function of fishes should be considered as tools to monitor ecological functional recovery in MPAs.Fil: Rincón Díaz, Martha Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina. State University of Oregon; Estados UnidosFil: Pittman, Simon. University Of Plymouth. School Of Marine Sciences; Reino UnidoFil: Eager, Aaron. University of New South Wales. Faculty of Science. School of Biological-earth and Environmental Sciences; AustraliaFil: Heppell, Selina. State University of Oregon; Estados Unidos73rd Annual Gulf And Caribbean Fisheries Institute Virtual MeetingMarathonEstados UnidosGulf and Caribbean Fisheries Institut
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