305 research outputs found
Emission and its back-reaction accompanying electron motion in relativistically strong and QED-strong pulsed laser fields
The emission from an electron in the field of a relativistically strong laser
pulse is analyzed. At pulse intensities of J > 2 10^22 W/cm2 the emission from
counter-propagating electrons is modified by the effects of Quantum
ElectroDynamics (QED), as long as the electron energy is sufficiently high: E >
1 GeV. The radiation force experienced by an electron is for the first time
derived from the QED principles and its applicability range is extended towards
the QED-strong fields.Comment: 14 pages, 5 figures. Submitted to Phys.Rev.
DETERMINATION DE LA VITESSE D'ECOULEMENT D'UN MILIEU GRANULAIRE PAR LA METHODE DE GALERKINE
The difficulties bound to the transport of the granular materials in the industry brought numerous authors to propose some models in order to control the out-flow of these materials. The works of POLDERMAN permit to determine the field of velocity of the out-flow in mass of
the unalterable granular materials from a mathematical model based on hypothesis according to which the angle Ï between the major main axis of the constraint and the half angle Ξ at the summit of a conical hopper is a linear function of Ξ with the following form: Ï = C1Ξ . For a given value of the ray r, he determines the out-flow velocity of the continuity equation by means of the unknown velocity for Ï = 0. Using the approached solution of the continuity equation calculated by the GALERKINE method, we determine the absolute error depending of the unknown velocity. With the given approximation precision the constraint on the unknown velocity is calculated
Dynamics of Emitting Electrons in Strong Electromagnetic Fields
We derive a modified non-perturbative Lorentz-Abraham-Dirac equation. It
satisfies the proper conservation laws, particularly, it conserves the
generalized momentum, the latter property eliminates the symmetry-breaking
runaway solution. The equation allows a consistent calculation of the electron
current, the radiation effect on the electron momentum, and the radiation
itself, for a single electron or plasma electrons in strong electromagnetic
fields. The equation is applied to a simulation of a strong laser pulse
interaction with a plasma target. Some analytical solutions are also provided.Comment: The original form of this paper was submitted to Phys. Rev. Lett. on
August 3, 2008. The current version of the paper is substantially extended
and includes modifications resulting from points raised during the review
proces
Defective Retroviral Endogenous RNA Is Efficiently Transmitted by Infectious Particles Produced on an Avian Retroviral Vector Packaging Cell Line
AbstractThis report describes the contamination of "helper-free" stocks of defective retroviral vector with particles bearing retroviral endogenous RNA. An avian leukosis virus-based packaging cell line was developed from LMH cells that bear the ev1, ev3, and ev6 retroviral endogenous loci. The results show that an endogenous retroviral transcript (ev3) was packaged into virions produced by this packaging cell line and was efficiently transferred along with the vector to target cells. The titer of the ev contaminant particles was estimated at 50 - 100 CA-p27gag-expressing units/ml of supernatant
Extended Coagulation Profiling in Isolated Traumatic Brain Injury:A CENTER-TBI Analysis
Background: Trauma-induced coagulopathy in traumatic brain injury (TBI) remains associated with high rates of complications, unfavorable outcomes, and mortality. The underlying mechanisms are largely unknown. Embedded in the prospective multinational Collaborative European Neurotrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI) study, coagulation profiles beyond standard conventional coagulation assays were assessed in patients with isolated TBI within the very early hours of injury. Methods: Results from blood samples (citrate/EDTA) obtained on hospital admission were matched with clinical and routine laboratory data of patients with TBI captured in the CENTER-TBI central database. To minimize confounding factors, patients with strictly isolated TBI (iTBI) (n = 88) were selected and stratified for coagulopathy by routine international normalized ratio (INR): (1) INR < 1.2 and (2) INR â„ 1.2. An INR > 1.2 has been well adopted over time as a threshold to define trauma-related coagulopathy in general trauma populations. The following parameters were evaluated: quickâs value, activated partial thromboplastin time, fibrinogen, thrombin time, antithrombin, coagulation factor activity of factors V, VIII, IX, and XIII, protein C and S, plasminogen, D-dimer, fibrinolysis-regulating parameters (thrombin activatable fibrinolysis inhibitor, plasminogen activator inhibitor 1, antiplasmin), thrombin generation, and fibrin monomers. Results: Patients with iTBI with INR â„ 1.2 (n = 16) had a high incidence of progressive intracranial hemorrhage associated with increased mortality and unfavorable outcome compared with patients with INR < 1.2 (n = 72). Activity of coagulation factors V, VIII, IX, and XIII dropped on average by 15â20% between the groups whereas protein C and S levels dropped by 20%. With an elevated INR, thrombin generation decreased, as reflected by lower peak height and endogenous thrombin potential (ETP), whereas the amount of fibrin monomers increased. Plasminogen activity significantly decreased from 89% in patients with INR < 1.2 to 76% in patients with INR â„ 1.2. Moreover, D-dimer levels significantly increased from a mean of 943 mg/L in patients with INR < 1.2 to 1,301 mg/L in patients with INR â„ 1.2. Conclusions: This more in-depth analysis beyond routine conventional coagulation assays suggests a counterbalanced regulation of coagulation and fibrinolysis in patients with iTBI with hemostatic abnormalities. We observed distinct patterns involving key pathways of the highly complex and dynamic coagulation system that offer windows of opportunity for further research. Whether the changes observed on factor levels may be relevant and explain the worse outcome or the more severe brain injuries by themselves remains speculative.</p
Whole proteome analyses on Ruminiclostridium cellulolyticum show a modulation of the cellulolysis machinery in response to cellulosic materials with subtle differences in chemical and structural properties
Lignocellulosic materials from municipal solid waste emerge as attractive resources for anaerobic digestion biorefinery. To increase the knowledge required for establishing efficient bioprocesses, dynamics of batch fermentation by the cellulolytic bacterium Ruminiclostridium cellulolyticum were compared using three cellulosic materials, paper handkerchief, cotton discs and Whatman filter paper. Fermentation of paper handkerchief occurred the fastest and resulted in a specific metabolic profile: it resulted in the lowest acetate-to-lactate and acetate-to-ethanol ratios. By shotgun proteomic analyses of paper handkerchief and Whatman paper incubations, 151 proteins with significantly different levels were detected, including 20 of the 65 cellulosomal components, 8 non-cellulosomal CAZymes and 44 distinct extracytoplasmic proteins. Consistent with the specific metabolic profile observed, many enzymes from the central carbon catabolic pathways had higher levels in paper handkerchief incubations. Among the quantified CAZymes and cellulosomal components, 10 endoglucanases mainly from the GH9 families and 7 other cellulosomal subunits had lower levels in paper handkerchief incubations. An in-depth characterization of the materials used showed that the lower levels of endoglucanases in paper handkerchief incubations could hypothetically result from its lower crystallinity index (50%) and degree of polymerization (970). By contrast, the higher hemicellulose rate in paper handkerchief (13.87%) did not result in the enhanced expression of enzyme with xylanase as primary activity, including enzymes from the xyl-doc cluster. It suggests the absence, in this material, of molecular structures that specifically lead to xylanase induction. The integrated approach developed in this work shows that subtle differences among cellulosic materials regarding chemical and structural characteristics have significant effects on expressed bacterial functions, in particular the cellulolysis machinery, resulting in different metabolic patterns and degradation dynamics.This work was supported by a grant [R2DS 2010-08] from Conseil Regional d'Ile-de-France through DIM R2DS programs (http://www.r2ds-ile-de-france.com/). Irstea (www.irstea.fr/) contributed to the funding of a PhD grant for the first author. The funders provided support in the form of salaries for author [NB], funding for consumables and laboratory equipment, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. Omics Services provided support in the form of salaries for authors [VS, MD], but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors [NB, VS, MD] are articulated in the 'author contributions' section.info:eu-repo/semantics/publishedVersio
Comparative effectiveness of intracranial hypertension management guided by ventricular versus intraparenchymal pressure monitoring:a CENTER-TBI study
Objective: To compare outcomes between patients with primary external ventricular device (EVD)âdriven treatment of intracranial hypertension and those with primary intraparenchymal monitor (IP)âdriven treatment. Methods: The CENTER-TBI study is a prospective, multicenter, longitudinal observational cohort study that enrolled patients of all TBI severities from 62 participating centers (mainly level I trauma centers) across Europe between 2015 and 2017. Functional outcome was assessed at 6Â months and a year. We used multivariable adjusted instrumental variable (IV) analysis with âcenterâ as instrument and logistic regression with covariate adjustment to determine the effect estimate of EVD on 6-month functional outcome. Results: A total of 878 patients of all TBI severities with an indication for intracranial pressure (ICP) monitoring were included in the present study, of whom 739 (84%) patients had an IP monitor and 139 (16%) an EVD. Patients included were predominantly male (74% in the IP monitor and 76% in the EVD group), with a median age of 46Â years in the IP group and 48 in the EVD group. Six-month GOS-E was similar between IP and EVD patients (adjusted odds ratio (aOR) and 95% confidence interval [CI] OR 0.74 and 95% CI [0.36â1.52], adjusted IV analysis). The length of intensive care unit stay was greater in the EVD group than in the IP group (adjusted rate ratio [95% CI] 1.70 [1.34â2.12], IV analysis). One hundred eighty-seven of the 739 patients in the IP group (25%) required an EVD due to refractory ICPs. Conclusion: We found no major differences in outcomes of patients with TBI when comparing EVD-guided and IP monitorâguided ICP management. In our cohort, a quarter of patients that initially received an IP monitor required an EVD later for ICP control. The prevalence of complications was higher in the EVD group. Protocol: The core study is registered with ClinicalTrials.gov, number NCT02210221, and the Resource Identification Portal (RRID: SCR_015582).</p
The burden of traumatic brain injury from low-energy falls among patients from 18 countries in the CENTER-TBI Registry: A comparative cohort study.
BACKGROUND: Traumatic brain injury (TBI) is an important global public health burden, where those injured by high-energy transfer (e.g., road traffic collisions) are assumed to have more severe injury and are prioritised by emergency medical service trauma triage tools. However recent studies suggest an increasing TBI disease burden in older people injured through low-energy falls. We aimed to assess the prevalence of low-energy falls among patients presenting to hospital with TBI, and to compare their characteristics, care pathways, and outcomes to TBI caused by high-energy trauma. METHODS AND FINDINGS: We conducted a comparative cohort study utilising the CENTER-TBI (Collaborative European NeuroTrauma Effectiveness Research in TBI) Registry, which recorded patient demographics, injury, care pathway, and acute care outcome data in 56 acute trauma receiving hospitals across 18 countries (17 countries in Europe and Israel). Patients presenting with TBI and indications for computed tomography (CT) brain scan between 2014 to 2018 were purposively sampled. The main study outcomes were (i) the prevalence of low-energy falls causing TBI within the overall cohort and (ii) comparisons of TBI patients injured by low-energy falls to TBI patients injured by high-energy transfer-in terms of demographic and injury characteristics, care pathways, and hospital mortality. In total, 22,782 eligible patients were enrolled, and study outcomes were analysed for 21,681 TBI patients with known injury mechanism; 40% (95% CI 39% to 41%) (8,622/21,681) of patients with TBI were injured by low-energy falls. Compared to 13,059 patients injured by high-energy transfer (HE cohort), the those injured through low-energy falls (LE cohort) were older (LE cohort, median 74 [IQR 56 to 84] years, versus HE cohort, median 42 [IQR 25 to 60] years; p < 0.001), more often female (LE cohort, 50% [95% CI 48% to 51%], versus HE cohort, 32% [95% CI 31% to 34%]; p < 0.001), more frequently taking pre-injury anticoagulants or/and platelet aggregation inhibitors (LE cohort, 44% [95% CI 42% to 45%], versus HE cohort, 13% [95% CI 11% to 14%]; p < 0.001), and less often presenting with moderately or severely impaired conscious level (LE cohort, 7.8% [95% CI 5.6% to 9.8%], versus HE cohort, 10% [95% CI 8.7% to 12%]; p < 0.001), but had similar in-hospital mortality (LE cohort, 6.3% [95% CI 4.2% to 8.3%], versus HE cohort, 7.0% [95% CI 5.3% to 8.6%]; p = 0.83). The CT brain scan traumatic abnormality rate was 3% lower in the LE cohort (LE cohort, 29% [95% CI 27% to 31%], versus HE cohort, 32% [95% CI 31% to 34%]; p < 0.001); individuals in the LE cohort were 50% less likely to receive critical care (LE cohort, 12% [95% CI 9.5% to 13%], versus HE cohort, 24% [95% CI 23% to 26%]; p < 0.001) or emergency interventions (LE cohort, 7.5% [95% CI 5.4% to 9.5%], versus HE cohort, 13% [95% CI 12% to 15%]; p < 0.001) than patients injured by high-energy transfer. The purposive sampling strategy and censorship of patient outcomes beyond hospital discharge are the main study limitations. CONCLUSIONS: We observed that patients sustaining TBI from low-energy falls are an important component of the TBI disease burden and a distinct demographic cohort; further, our findings suggest that energy transfer may not predict intracranial injury or acute care mortality in patients with TBI presenting to hospital. This suggests that factors beyond energy transfer level may be more relevant to prehospital and emergency department TBI triage in older people. A specific focus to improve prevention and care for patients sustaining TBI from low-energy falls is required.CENTER-TBI was supported by the
European Union 7th Framework program (EC grant
602150), recipient A.I.R. Maas. Additional funding
was obtained from the Hannelore Kohl Stiftung
(Germany) - recipient A.I.R. Maas, from OneMind
(USA) - recipient A.I.R. Maas and from Integra
LifeSciences Corporation (USA) - recipient A.I.R.
Maas. The funders had no role in study design,
data collection and analysis, decision to publish, or
preparation of the manuscript
De las catacumbas a los Ășltimos confines: violencia, sentido y representaciĂłn en los periplos del martirio
En este trabajo propongo un anĂĄlisis transversal de las figuras del mĂĄrtir y del martirio. Recurriendo a la nociĂłn de mediaciĂłn, en la primera parte analizo el rol protagĂłnico de las representaciones del martirio en las prĂĄcticas de la memoria durante la segunda mitad del siglo XVI. Analizo algunas de las condiciones que contribuyeron a la emergencia de una "cultura del martirio" y el rol de las mediaciones en tal surgimiento. En la segunda parte, estudio la forma en que el (re)descubrimiento de las catacumbas romanas, abriĂł un campo de producciĂłn de sentido en torno a la figura del martirio. En la tercera parte, centrĂĄndome en la CompañĂa de JesĂșs, analizo algunas mediaciones a travĂ©s de las cuĂĄles las figuras del martirio transgredieron las fronteras de iglesias y conventos para proyectarse a los Ășltimos confines en un mundo en plena expansiĂłn.Neste artigo proponho uma anĂĄlise transversal das figuras do mĂĄrtir e do martĂrio. Usando a noção de mediação, na primeira parte eu tento analisar o papel de liderança de representaçÔes de martĂrio em prĂĄticas de memĂłria durante a segunda metade do sĂ©culo XVI. Eu analiso algumas das condiçÔes que contribuĂram para o surgimento de uma "cultura do martĂrio" e o papel da mediação nesta emergĂȘncia. Na segunda parte, eu estudo como a (re) descoberta das catacumbas romanas abriu um campo de produção de significados em torno da figura do martĂrio. Na terceira parte, com foco na Companhia de Jesus, analiso algumas mediaçÔes pelas quais as representaçÔes do martĂrio transgrediram as fronteiras de igrejas e conventos para se projetar nas fronteiras de um mundo em plena expansĂŁo mundial.This paper proposes a cross-sectional analysis of martyr and martyrdom. Through the notion of mediation, in the first part I analyze the leading role of representations of martyrdom in memory practices during the second half of the sixteenth century. I analyze some of the conditions that contributed to the emergence of a "martyrdom's culture" and the role of mediation in such emergence. The second part studies how the (re)discovery of the Roman catacombs encouraged the production of meanings around the figure of martyrdom. In the third part, focusing on the Society of Jesus, I analyze a few instances of mediation through which the figures of martyrdom transgressed the boundaries of churches and convents to project themselves to the last frontiers of a world in full expansion.Fil: Salamanca Villamizar, Carlos Arturo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentin
- âŠ