1,336 research outputs found
Global existence and exponential decay for hyperbolic dissipative relativistic fluid theories
We consider dissipative relativistic fluid theories on a fixed flat, compact,
globally hyperbolic, Lorentzian manifold. We prove that for all initial data in
a small enough neighborhood of the equilibrium states (in an appropriate
Sobolev norm), the solutions evolve smoothly in time forever and decay
exponentially to some, in general undetermined, equilibrium state. To prove
this, three conditions are imposed on these theories. The first condition
requires the system of equations to be symmetric hyperbolic, a fundamental
requisite to have a well posed and physically consistent initial value
formulation. The second condition is a generic consequence of the entropy law,
and is imposed on the non principal part of the equations. The third condition
is imposed on the principal part of the equations and it implies that the
dissipation affects all the fields of the theory. With these requirements we
prove that all the eigenvalues of the symbol associated to the system of
equations of the fluid theory have strictly negative real parts, which in fact,
is an alternative characterization for the theory to be totally dissipative.
Once this result has been obtained, a straight forward application of a general
stability theorem due to Kreiss, Ortiz, and Reula, implies the results above
mentioned.Comment: 10 pages, Late
Dilepton radiation and bulk viscosity in heavy-ion collisions
Starting from IP-Glasma initial conditions, we investigate the effects of
bulk pressure on thermal dilepton production at the Relativistic Heavy Ion
Collider (RHIC) and the Large Hadron Collider (LHC) energies. Though results of
the thermal dilepton under the influence of both bulk and shear viscosity
is presented for top RHIC energy, more emphasis is put on LHC energy where such
a calculation is computed for the first time. The effects of the bulk pressure
on thermal dilepton at the LHC are explored through bulk-induced
modifications on the dilepton yield.Comment: Talk given at the 8th International Conference on Hard and
Electromagnetic Probes of High-Energy Nuclear Collisions (Hard Probes 2016),
September 23-27 2016, Wuhan, China; 4 pages, LaTeX, 2 PDF figure
Bulk viscous effects on flow and dilepton radiation in a hybrid approach
Starting from IP-Glasma initial conditions, we investigate the effects of
bulk pressure on low mass dilepton production at the Relativistic Heavy Ion
Collider (RHIC) and the Large Hadron Collider (LHC) energies. Though thermal
dilepton is affected by the presence of both bulk and shear viscosity,
whether or not these effects can be measured depends on the dilepton "cocktail"
contribution to the the low mass dilepton . Combining the thermal and
"cocktail" dileptons, the effects of bulk viscosity on total dilepton is
investigated.Comment: Proceedings for the 26th International Conference on
Ultrarelativistic Nucleus-Nucleus Collisions (Quark Matter 2017), February
5-11 2017, Chicago, Illinois, US
Mild cognitive impairment, degenerative and vascular dementia as predictors of intra-hospital, short- and long-term mortality in the oldest old
Background and aims: The relative weight of various etiologies of dementia and mild cognitive impairment (MCI) as predictors of intra-hospital, short- and long-term mortality in very old acutely ill patients suffering from multiple comorbid conditions remains unclear. We investigated intra-hospital, 1- and 5-year mortality risk associated with dementia and its various etiologies in a very old population after discharge from acute care. Methods: Prospective cohort study of 444 patients (mean age 85 years; 74% female) discharged from the acute geriatric unit of Geneva University Hospital. On admission, each subject underwent standardized evaluation of cognitive and comorbid conditions. Patients were followed yearly by the same team. Predictive variables were age, sex, cognitive diagnosis, dementia etiology and severity. Survival during hospitalization, at 1- and 5-year follow-ups was the outcome of interest evaluated with Cox proportional hazard models. Results: Two hundred and six patients were cognitively normal, 48 had MCI, and 190 had dementia: of these, there were 75 cases of Alzheimer's disease (AD), 20 of vascular dementia (VaD), 82 of mixed dementia (MD) and 13 of other types of dementia. The groups compared were statistically similar in age, sex, education level and comorbidity score. After 5 years of follow-up, 60% of the patients had died. Regarding intra-hospital mortality, none of the predictive variables was associated with mortality. MCI, AD and MD were not predictive of short- or long-term mortality. Features significantly associated with reduced survival at 1 and 5 years were being older, male, and having vascular or severe dementia. When all the variables were added in the multiple model, the dementia effect completely disappeared. Conclusions: Dementia (all etiologies) is not predictive of mortality. The observed VaD effect is probably linked to cardiovascular risk comorbidities: hypertension, stroke and hyperlipidemi
Globalisierung und regionale Integration: Ökonomische Entwicklungen, Perspektiven und Grenzen
Eine zentrale vertretende These der Ökonomie lautet: Die Aufhebung von Beschränkungen im Handel und Kapitalverkehr weltweit vermehrt die Wohlfahrt. Internationale Abkommen und Zollunionen verfolgen das Ziel des Freihandels. Auch das europäische Integrationsprojekt basiert mit dem Binnenmarktprogramm und den vertraglich abgesicherten vier Freiheiten, für Handel, Kapital, Personen und Dienstleistungen, auf dieser Grundidee. Im Rahmen der EU wird dies noch durch die Währungsunion ergänzt. Aber an der These der wohlfahrtssteigernden Wirkung des Freihandels gibt es vermehrt Kritik. Die Finanz- und Eurokrisen haben zusätzlich die Debatten über die Erweiterung und Vertiefung der EU einschließlich der Europäischen Währungsunion verstärkt. Auch wirft das geplante transatlantische Freihandelsabkommen grundsätzliche Fragen von Grenzen der ökonomischen Integration auf. Zu diesen Themen fand vom 10. bis 12. Juli 2015 eine wissenschaftliche Tagung unter der Leitung von Wolfgang Quaisser in der Akademie für Politische Bildung Tutzing statt. Einige der dort vorgestellten Vorträge werden hier veröffentlicht
Demented versus non-demented very old inpatients: the same comorbidities but poorer functional and nutritional status
Background: demented patients have been reported to be healthier than other old people of the same age. Objectives: to assess comorbid conditions, functional and nutritional status in medically ill hospitalised patients with normal cognition or affected by dementia of various causes and severities, or mild cognitive impairment (MCI). Design and Setting: a prospective study was carried out, between January and December 2004, in the Rehabilitation and Geriatric Hospital (HOGER). Methods: activities of daily living (ADL), instrumental activities of daily living (IADL) and mini nutritional assessment (MNA) scores were assessed as a function of the status of the patient two weeks before admission to hospital. On admission, cognitive status was assessed by a systematic battery of neuropsychological tests, comorbid conditions were assessed with the Charlson comorbidity index (CCI), and body mass index (BMI) and functional independence measure (FIM) were determined. BMI and FIM were also determined on discharge. Results: we studied 349 patients (mean age 85.2±6.7; 76% women): 161 (46.1%) cognitively normal, 37 (10.6%) with MCI and 151 (43.3%) demented (61 Alzheimer's disease (AD), 62 mixed dementia (MD) and 17 vascular dementia (VaD)). ADL, IADL, FIM and MNA scores on admission decreased with cognitive status, regardless of the type of dementia. Functionality at discharge remained significantly lower in demented patients than in other patients. CCI was high and similar in all three groups (mean 4.6±2.7). Patients with VaD had poorer health than other demented patients, with a higher average comorbidity score, more frequent hypertension, stroke and hyperlipidaemia. Comorbidity did not increase with severity levels of dementia. Conclusions: in this cohort of very old inpatients, demented patients, non-demented patients and patients with MCI had similar levels of comorbidity, but demented patients had a poorer functional and nutritional statu
A luciferase-based quick potency assay to predict chondrogenic differentiation.
Chondrogenic differentiation of adipose derived stem cells (ASC) is challenging but highly promising for cartilage repair. Large donor variability of chondrogenic differentiation potential raises the risk for transplantation of cells with reduced efficacy and a low chondrogenic potential. Therefore quick potency assays are required in order to control the potency of the isolated cells before cell transplantation. Current in vitro methods to analyze the differentiation potential are time consuming and thus, a novel enhancer and tissue-specific promoter combination was employed for the detection of chondrogenic differentiation of ASC in a novel quick potency bioassay. Human primary ASC were co-transfected with the Metridia luciferase based collagen type II reporter gene pCMVE_ACDCII-MetLuc together with a Renilla control plasmid and analyzed for their chondrogenic potential. On day 3 after chondrogenic induction, the luciferase activity was induced in all tested donors under three dimensional (3D) culture conditions and in a second approach also under 2D culture conditions. With our newly developed quick potency bioassay we can determine chondrogenic potential already after 3 days of chondrogenic induction and under 2D culture conditions. This will enhance the efficiency of testing cell functionality, which should allow in the future to predict the suitability of cells derived from individual patients for cell therapies, in a very short time and at low costs
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