207 research outputs found

    Drinfeld twist and symmetric Bethe vectors of the open XYZ chain with non-diagonal boundary terms

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    With the help of the Drinfeld twist or factorizing F-matrix for the eight-vertex solid-on-solid (SOS) model, we find that in the F-basis provided by the twist the two sets of pseudo-particle creation operators simultaneously take completely symmetric and polarization free form. This allows us to obtain the explicit and completely symmetric expressions of the two sets of Bethe states of the model.Comment: Latex file, 25 page

    Simulating Thermal Explosion of Octahydrotetranitrotetrazine-based explosives: Model Comparison with Experiment

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    The authors compare two-dimensional model results with measurements for the thermal, chemical and mechanical behavior in a thermal explosion experiment. Confined high explosives are heated at a rate of 1 C per hour until an explosion is observed. The heating, ignition, and deflagration phases are modeled using an Arbitrarily Lagrangian-Eulerian code (ALE3D) that can handle a wide range of time scales that vary from a structural to a dynamic hydro time scale. During the pre-ignition phase, quasi-static mechanics and diffusive thermal transfer from a heat source to the HE are coupled with the finite chemical reactions that include both endothermic and exothermic processes. Once the HE ignites, a hydro dynamic calculation is performed as a burn front propagates through the HE. Two octahydrotetranitrotetrazine (HMX)-based explosives, LX-04 and LX-10, are considered, whose chemical-thermal-mechanical models are constructed based on measurements of thermal and mechanical properties along with small scale thermal explosion measurements. The present HMX modeling work shows very first violence calculations with thermal predictions associated with a confined thermal explosion test. The simulated dynamic response of HE confinement during the explosive phase is compared to measurements in larger scale thermal explosion tests. The explosion temperatures for both HE's are predicted to within 1 C. Calculated and measured wall strains provide an indication of vessel pressurization during the heating phase and violence during the explosive phase

    Déclaration sur l’approche par l’archéologie sociale du changement climatique

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    Manifiesto sobre Arqueología Social del Cambio Climático aprobado en la Cumbre SACC celebrada en Kiel. Aprobado y firmado el 6 de septiembre de 2021.[ES] El SACC es un grupo independiente, constituido en Kiel, de investigadores e investigadoras que trabajan sobre cambio climático. El objetivo de SACC es reunir científicos y científicas internacionales y representantes de importantes organizaciones internacionales de las áreas de arqueología, paleoecología y gestión del patrimonio para con el fin de discutir y evaluar la contribución de la investigación arqueológica y paleo-ecológica para comprender la interrelación entre el cambio social, el cultural, el ecológico y el climático. Pretendemos resaltar cómo la arqueología, a través del estudio de la conducta adaptativa en el pasado, es capaz de reforzar tanto la resiliencia socio-ecológica de nuestras sociedades, como su capacidad adaptativa ante el actual cambio climático. Además, pretendemos contribuir a la comprensión del impacto del cambio climático en los yacimientos y sitios arqueológicos y patrimoniales, así como en los paisajes culturales, los museos, las colecciones y archivos patrimoniales. SACC celebrará cumbres cada dos años y emitirá una declaración o manifiesto al término de cada una de ellas. S ACC está organizada por un comité interino presidido por las personas convocantes del SACC 1.[EN] SACC is an independent group of researchers working on climate change in the past constituted in Kiel. The aim of SACC is to bring together international scientists and representatives of important international organisations in the fields of archaeology, paleoecology and heritage management to discuss and evaluate the contribution of archaeological and paleo-ecological research to understand the link between social, cultural, ecological and climatic change; and to highlight how archaeology, through the study of past adaptive behaviour, is able to enhance socio-ecological resilience of societies as well as their adaptive capacity to current climate change; furthermore, to contribute to the understanding of the impact of climate change on archaeological and heritage sites as well as on cultural landscapes, museums, collections, and archives. SACC will hold its summit every second year with a declaration at the end of each summit. SACC is organized by a steering committee chaired by the SACC 1 organisers.[FR] Le SACC est un groupe indépendant de chercheurs travaillant sur le changement climatique dans le passé, qui s’est formé à Kiel. L’objectif du S ACC est de réunir des scientifiques internationaux et des représentants d’organisations internationales importantes dans les domaines de l’archéologie, de la paléoécologie et de la gestion du patrimoine. Il a pour objectif de discuter et d’évaluer la contribution de la recherche archéologique et paléo-écologique à la compréhension du lien entre les changements sociaux, culturels, écologiques et climatiques et de souligner comment l’archéologie, par l’étude du comportement adaptatif du passé, est capable d’améliorer la résilience socioécologique des sociétés ainsi que leur capacité d’adaptation au changement climatique actuel. En outre, il contribue à la compréhension de l’impact du changement climatique sur les sites archéologiques et patrimoniaux ainsi que sur les paysages culturels, les musées, les collections et les archives. Le SACC tiendra son conseil tous les deux ans avec une déclaration à la fin de chaque conseil. Il est organisé par un comité de pilotage présidé par les organisateurs de SACC 1.Peer reviewe

    Identification of DNA-Damage DNA-Binding Protein 1 as a Conditional Essential Factor for Cytomegalovirus Replication in Interferon-γ-Stimulated Cells

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    The mouse cytomegaloviral (MCMV) protein pM27 represents an indispensable factor for viral fitness in vivo selectively, antagonizing signal transducer and activator of transcription 2 (STAT2)-mediated interferon signal transduction. We wished to explore by which molecular mechanism pM27 accomplishes this effect. We demonstrate that pM27 is essential and sufficient to curtail the protein half-life of STAT2 molecules. Pharmacologic inhibition of the proteasome restored STAT2 amounts, leading to poly-ubiquitin-conjugated STAT2 forms. PM27 was found in complexes with an essential host ubiquitin ligase complex adaptor protein, DNA-damage DNA-binding protein (DDB) 1. Truncation mutants of pM27 showed a strict correlation between DDB1 interaction and their ability to degrade STAT2. SiRNA-mediated knock-down of DDB1 restored STAT2 in the presence of pM27 and strongly impaired viral replication in interferon conditioned cells, thus phenocopying the growth attenuation of M27-deficient virus. In a constructive process, pM27 recruits DDB1 to exploit ubiquitin ligase complexes catalyzing the obstruction of the STAT2-dependent antiviral state of cells to permit viral replication

    Crystal and melt inclusion timescales reveal the evolution of magma migration before eruption

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    Volatile element concentrations measured in melt inclusions are a key tool used to understand magma migration and degassing, although their original values may be affected by different re-equilibration processes. Additionally, the inclusion-bearing crystals can have a wide range of origins and ages, further complicating the interpretation of magmatic processes. To clarify some of these issues, here we combined olivine diffusion chronometry and melt inclusion data from the 2008 eruption of Llaima volcano (Chile). We found that magma intrusion occurred about 4 years before the eruption at a minimum depth of approximately 8 km. Magma migration and reaction became shallower with time, and about 6 months before the eruption magma reached 3–4 km depth. This can be linked to reported seismicity and ash emissions. Although some ambiguities of interpretation still remain, crystal zoning and melt inclusion studies allow a more complete understanding of magma ascent, degassing, and volcano monitoring data.NRF (Natl Research Foundation, S’pore)MOE (Min. of Education, S’pore)Published versio

    Pregnancy-related pelvic girdle pain: an update

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    A large number of scientists from a wide range of medical and surgical disciplines have reported on the existence and characteristics of the clinical syndrome of pelvic girdle pain during or after pregnancy. This syndrome refers to a musculoskeletal type of persistent pain localised at the anterior and/or posterior aspect of the pelvic ring. The pain may radiate across the hip joint and the thigh bones. The symptoms may begin either during the first trimester of pregnancy, at labour or even during the postpartum period. The physiological processes characterising this clinical entity remain obscure. In this review, the definition and epidemiology, as well as a proposed diagnostic algorithm and treatment options, are presented. Ongoing research is desirable to establish clear management strategies that are based on the pathophysiologic mechanisms responsible for the escalation of the syndrome's symptoms to a fraction of the population of pregnant women
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