5,651 research outputs found
A configurational approach to servitization: Review and research directions
In this article, the authors extend the current literature on servitization by taking a configurational perspective, aiming to understand the interplay between the drivers (conditions) that lead to certain equifinal outcomes of servitization. By taking stock of the servitization literature using the contingency theory of strategy as a foundational theory and the strategy–structure–environment approach as a primary framework to systematically review and analyze the identified configurational servitization studies, the authors identify commonalities and gaps in the literature and set directions for future research. EPSRC New Industrial Systems: OMMS - Optimising Me Manufacturing System [EP/R022534/1
Probing strongly coupled anisotropic plasma
We calculate the static potential, the drag force and the jet quenching
parameter in strongly coupled anisotropic N=4 super Yang-Mills plasma. We find
that the jet quenching is in general enhanced in presence of anisotropy
compared to the isotropic case and that its value depends strongly on the
direction of the moving quark and the direction along which the momentum
broadening occurs. The jet quenching is strongly enhanced for a quark moving
along the anisotropic direction and momentum broadening happens along the
transverse one. The parameter gets lower for a quark moving along the
transverse direction and the momentum broadening considered along the
anisotropic one. Finally, a weaker enhancement is observed when the quark moves
in the transverse plane and the broadening occurs on the same plane. The drag
force for quark motion parallel to the anisotropy is always enhanced. For
motion in the transverse space the drag force is enhanced compared to the
isotropic case only for quarks having velocity above a critical value. Below
this critical value the force is decreased. Moreover, the drag force along the
anisotropic direction is always stronger than the force in the transverse
space. The diffusion time follows exactly the inverse relations of the drag
forces. The static potential is decreased and stronger decrease observed for
quark-antiquark pair aligned along the anisotropic direction than the
transverse one. We finally comment on our results and elaborate on their
similarities and differences with the weakly coupled plasmas.Comment: 1+44 pages, 18 Figures; Added results on static force; Added
references; version published in JHE
Benzophénanthridines isolées de Zanthoxylum psammophilum
Dix-huit composés dont deux nouvelles benzophénanthridines la 8-méthoxy-7,8-dihydrofagaridine 1 et la 8-acétonyl-7,8-dihydrofagaridine 2 ont été isolés des racines de Zanthoxylum psammophilum (Rutaceae). La structure de ces composés (1-18) a été déterminée principalement par l’utilisation de la spectroscopie de RMN 1D (1H et 13C) et 2D (COSY, NOESY, HSQC, HMBC). Le composé 1 a montré une activité antimicrobienne sur S. Aureus.Mots clés: Rutaceae, alcaloïdes, 8-méthoxy-7,8-dihydrofagaridine, 8- acétonyl-7,8-dihydrofagaridin
Drag force in a strongly coupled anisotropic plasma
We calculate the drag force experienced by an infinitely massive quark
propagating at constant velocity through an anisotropic, strongly coupled N=4
plasma by means of its gravity dual. We find that the gluon cloud trailing
behind the quark is generally misaligned with the quark velocity, and that the
latter is also misaligned with the force. The drag coefficient can be
larger or smaller than the corresponding isotropic value depending on the
velocity and the direction of motion. In the ultra-relativistic limit we find
that generically . We discuss the conditions under which this
behaviour may extend to more general situations.Comment: 25 pages, 13 figures; v2: minor changes, added reference
The Surgical Infection Society revised guidelines on the management of intra-abdominal infection
Background: Previous evidence-based guidelines on the management of intra-abdominal infection (IAI) were published by the Surgical Infection Society (SIS) in 1992, 2002, and 2010. At the time the most recent guideline was released, the plan was to update the guideline every five years to ensure the timeliness and appropriateness of the recommendations.
Methods: Based on the previous guidelines, the task force outlined a number of topics related to the treatment of patients with IAI and then developed key questions on these various topics. All questions were approached using general and specific literature searches, focusing on articles and other information published since 2008. These publications and additional materials published before 2008 were reviewed by the task force as a whole or by individual subgroups as to relevance to individual questions. Recommendations were developed by a process of iterative consensus, with all task force members voting to accept or reject each recommendation. Grading was based on the GRADE (Grades of Recommendation Assessment, Development, and Evaluation) system; the quality of the evidence was graded as high, moderate, or weak, and the strength of the recommendation was graded as strong or weak. Review of the document was performed by members of the SIS who were not on the task force. After responses were made to all critiques, the document was approved as an official guideline of the SIS by the Executive Council.
Results: This guideline summarizes the current recommendations developed by the task force on the treatment of patients who have IAI. Evidence-based recommendations have been made regarding risk assessment in individual patients; source control; the timing, selection, and duration of antimicrobial therapy; and suggested approaches to patients who fail initial therapy. Additional recommendations related to the treatment of pediatric patients with IAI have been included.
Summary: The current recommendations of the SIS regarding the treatment of patients with IAI are provided in this guideline
A metabolite-derived protein modification integrates glycolysis with KEAP1-NRF2 signalling.
Mechanisms that integrate the metabolic state of a cell with regulatory pathways are necessary to maintain cellular homeostasis. Endogenous, intrinsically reactive metabolites can form functional, covalent modifications on proteins without the aid of enzymes1,2, and regulate cellular functions such as metabolism3-5 and transcription6. An important 'sensor' protein that captures specific metabolic information and transforms it into an appropriate response is KEAP1, which contains reactive cysteine residues that collectively act as an electrophile sensor tuned to respond to reactive species resulting from endogenous and xenobiotic molecules. Covalent modification of KEAP1 results in reduced ubiquitination and the accumulation of NRF27,8, which then initiates the transcription of cytoprotective genes at antioxidant-response element loci. Here we identify a small-molecule inhibitor of the glycolytic enzyme PGK1, and reveal a direct link between glycolysis and NRF2 signalling. Inhibition of PGK1 results in accumulation of the reactive metabolite methylglyoxal, which selectively modifies KEAP1 to form a methylimidazole crosslink between proximal cysteine and arginine residues (MICA). This posttranslational modification results in the dimerization of KEAP1, the accumulation of NRF2 and activation of the NRF2 transcriptional program. These results demonstrate the existence of direct inter-pathway communication between glycolysis and the KEAP1-NRF2 transcriptional axis, provide insight into the metabolic regulation of the cellular stress response, and suggest a therapeutic strategy for controlling the cytoprotective antioxidant response in several human diseases
Aidnogenesis via Leptogenesis and Dark Sphalerons
We discuss aidnogenesis, the generation of a dark matter asymmetry via new
sphaleron processes associated to an extra non-abelian gauge symmetry common to
both the visible and the dark sectors. Such a theory can naturally produce an
abundance of asymmetric dark matter which is of the same size as the lepton and
baryon asymmetries, as suggested by the similar sizes of the observed baryonic
and dark matter energy content, and provide a definite prediction for the mass
of the dark matter particle. We discuss in detail a minimal realization in
which the Standard Model is only extended by dark matter fermions which form
"dark baryons" through an SU(3) interaction, and a (broken) horizontal symmetry
that induces the new sphalerons. The dark matter mass is predicted to be
approximately 6 GeV, close to the region favored by DAMA and CoGeNT.
Furthermore, a remnant of the horizontal symmetry should be broken at a lower
scale and can also explain the Tevatron dimuon anomaly.Comment: Minor changes, discussion of present constraints expanded. 16 pages,
2 eps figures, REVTeX
Nitrogen and sulphur management: challenges for organic sources in temperate agricultural systems
A current global trend towards intensification or specialization of agricultural enterprises has been accompanied by increasing public awareness of associated environmental consequences. Air and water pollution from losses of nutrients, such as nitrogen (N) and sulphur (S), are a major concern. Governments have initiated extensive regulatory frameworks, including various land use policies, in an attempt to control or reduce the losses. This paper presents an overview of critical input and loss processes affecting N and S for temperate climates, and provides some background to the discussion in subsequent papers evaluating specific farming systems. Management effects on potential gaseous and leaching losses, the lack of synchrony between supply of nutrients and plant demand, and options for optimizing the efficiency of N and S use are reviewed. Integration of inorganic and organic fertilizer inputs and the equitable re-distribution of nutrients from manure are discussed. The paper concludes by highlighting a need for innovative research that is also targeted to practical approaches for reducing N and S losses, and improving the overall synchrony between supply and demand
A multifunctional serine protease primes the malaria parasite for red blood cell invasion
The malaria parasite Plasmodium falciparum replicates within an intraerythrocytic parasitophorous vacuole (PV). Rupture of the host cell allows release (egress) of daughter merozoites, which invade fresh erythrocytes. We previously showed that a subtilisin-like protease called PfSUB1 regulates egress by being discharged into the PV in the final stages of merozoite development to proteolytically modify the SERA family of papain-like proteins. Here, we report that PfSUB1 has a further role in ‘priming' the merozoite prior to invasion. The major protein complex on the merozoite surface comprises three proteins called merozoite surface protein 1 (MSP1), MSP6 and MSP7. We show that just before egress, all undergo proteolytic maturation by PfSUB1. Inhibition of PfSUB1 activity results in the accumulation of unprocessed MSPs on the merozoite surface, and erythrocyte invasion is significantly reduced. We propose that PfSUB1 is a multifunctional processing protease with an essential role in both egress of the malaria merozoite and remodelling of its surface in preparation for erythrocyte invasion
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