52 research outputs found
On the asymptotic behaviour of solutions to the fractional porous medium equation with variable density
We are concerned with the long time behaviour of solutions to the fractional
porous medium equation with a variable spatial density. We prove that if the
density decays slowly at infinity, then the solution approaches the
Barenblatt-type solution of a proper singular fractional problem. If, on the
contrary, the density decays rapidly at infinity, we show that the minimal
solution multiplied by a suitable power of the time variable converges to the
minimal solution of a certain fractional sublinear elliptic equation.Comment: To appear in DCDS-
Noble gas and carbon isotope systematics at the seemingly inactive Ciomadul volcano (EasternâCentral Europe, Romania): evidence for volcanic degassing
Ciomadul is the youngest volcano in the Carpathian-Pannonian Region, Eastern-Central Europe, which last erupted 30 ka. This volcano is considered to be inactive, however, combined evidence from petrologic and magnetotelluric data, as well as seismic tomography studies suggest the existence of a subvolcanic crystal mush with variable melt content. The volcanic area is characterized by high CO2 gas output rate, with a minimum of 8.7 Ă 103 t yr-1. We investigated 31 gas emissions at Ciomadul to constrain the origin of the volatiles. The ÎŽ13C-CO2 and 3He/4He compositions suggest the outgassing of a significant component of mantle-derived fluids. The He isotope signature in the outgassing fluids (up to 3.10 Ra) is lower than the values in the peridotite xenoliths of the nearby alkaline basalt volcanic field (R/Ra 5.95Ra±0.01) which are representative of a continental lithospheric mantle and significantly lower than MORB values. Considering the chemical characteristics of the Ciomadul dacite, including trace element and Sr- Nd and O isotope compositions, an upper crustal contamination is less probable, whereas the primary magmas could have been derived from an enriched mantle source. The low He isotopic ratios could indicate a strongly metasomatized mantle lithosphere. This could be due to infiltration of subduction-related fluids and postmetasomatic ingrowth of radiogenic He. The metasomatic fluids are inferred to have contained subducted carbonate material resulting in a heavier carbon isotope composition (13C is in the range of -1.4 to -4.6 â°) and an increase of CO2/3He ratio. Our study shows the magmatic contribution to the emitted gases
The need for change of the transport mode in the great cities of Romania
This paper describes how the development of the great cities in Romania, especially the capital of Bucharest, and the dramatic rise in the number of cars has contributed to the pollution of these cities and resulted in horrific urban traffic, particularly during the morning and evening rush hours. To provide alternative transportation in Bucharest and the surrounding areas, Urban Transport Administration of Bucharest (RATB) uses 300 km of tram lines with a park of 500 tram wagons, 18 trolley lines with a 485 km network and a park of 300 trolleys, the bus transport system with a 2,900 km network and a park of 1,300 buses, 3 Light Rail (LR) lines and 4 subway lines. During rush hour, the tram and trolley lines are obstructed by cars most of the time, so the average transport speed is 6â9 km/h for trolleys and 8â10 km/h for trams. The travel time for cars is around 220,000 vehicles/hour, 18,000 vehicles/hour for cabs, and 854,000 passengers/hour for urban transportation with electrical vehicles and buses. The impact on the environment can be measured in noise levels, which for 2007 were estimated at 62.8 dB and very high polluting car emissions. This paper will examine the decision factors and the planning concerns to provide a more efficient urban transport in Bucharest and other great cities in Romania, especially with electric vehicles. The paper proposes a methodology to optimize the selection mode and the track design for LR, using existing tram lines with the necessary additions, the construction of new subway lines for the busy areas and the continuous development of the tram and trolley urban transportation network
CercetÄri arheologice la CĂąmpulung, Ăźn zona vechii reĆedinĆŁe domneĆti (2000â2005) / Les fouilles entreprises dans la zone de lâancienne rĂ©sidence princiĂšre de CĂąmpulung (2000â2005)
Lâancienne rĂ©sidence des premiers voĂŻĂ©vodes de la Valachie pose de nombreuses questions concernant lâĂ©glise ainsi que les autres Ă©lĂ©ments composants de lâensemble, parmi lesquelles lâidentification de la maison princiĂšre prĂ©sente un intĂ©rĂȘt particulier. Au XVIIe siĂšcle, suite Ă la fondation du monastĂšre, lâensemble a Ă©tĂ© entiĂšrement modifiĂ©. LâĂ©glise princiĂšre, abĂźmĂ©e par un tremblement de terre, fĂ»t rebĂątie en 1635 et les bĂątiments monastiques ont Ă©tĂ© Ă©rigĂ©s sur un emplacement que les anciennes constructions dĂ©molies. Les recherches archĂ©ologiques entreprises Ă lâancienne rĂ©sidence princiĂšre de CĂąmpulung en 1975â 1977, 1981â 1982, 1984 et 2000â 2005 ont mis Ă jour des vestiges du XIVe siĂšcle, en Ă©lucidant aussi les problĂšmes concernant lâĂ©volution ultĂ©rieure de lâensemble architectural. DĂšs que la rĂ©sidence princiĂšre ne fut plus utilisĂ©e, lâespace qui entourait la plus importante Ă©glise de CĂąmpulung, oĂč Ă©taient enterrĂ©s les deux premiers princes de la Valachie et, aprĂšs eux, certains grands boyards, a Ă©tĂ© utilisĂ© avec prĂ©dilection comme lieu de sĂ©pulture par les citadins. Lâensemble a Ă©tĂ© entiĂšrement modifiĂ© au XVIIe siĂšcle, suite Ă la fondation du monastĂšre en 1635. LâĂ©glise a Ă©tĂ© rebĂątie et les bĂątiments monastiques ont Ă©tĂ© Ă©rigĂ©s aprĂšs la dĂ©molition des anciennes constructions, qui nâĂ©taient plus utilisĂ©es. Un problĂšme de grand intĂ©rĂȘt est celui de lâidentification de la rĂ©sidence des voĂŻĂ©vodes. On a essayĂ© dâattribuer Ă une phase de construction du XIVe siĂšcle la cave de la maison situĂ©e au sud-ouest de lâĂ©glise. Les fouilles de 1975â 1977 ont prouvĂ© que cette cave date du XVIIe siĂšcle. Lors de sa construction ont Ă©tĂ© dĂ©truites les derniers restes du mur qui entourait lâĂ©glise au XIVe siĂšcle, mur dĂ©mantelĂ© au XVe siĂšcle, et dâautres restes de construction datant du XVe siĂšcle, ainsi que des tombes du XVIe siĂšcle. Lâancienne maison des voĂŻĂ©vodes doit donc ĂȘtre cherchĂ©e ailleurs. En essayant dâobtenir des informations sur les vestiges de lâensemble, les fouilles entreprises en 2000â 2003 ont Ă©tĂ© concentrĂ©es dans la zone situĂ©e a lâest de lâĂ©glise et celles de 2004â 2005 vers le sud-est. En dehors de lâensemble du monastĂšre, on a effectuĂ© un sondage sur le terrain situĂ© au No. 76, rue Negru VodÄ, en obtenant des renseignements sur lâhabitat urbain des XIVeâ XVIIe siĂšcles. Les fouilles ont mis Ă jour des vestiges notables quâon peut dater au XIVe siĂšcle, dans la zone situĂ©e a lâest de lâĂ©glise voĂŻĂ©vodale. Parmi celles-ci on doit mentionner une partie, mise Ă jour sur une largeur dâenviron 10 mĂštres, dâun Ă©difice aux murs en pierre, dâun mĂštre dâĂ©paisseur, avec un pavement en briques Ă lâintĂ©rieur et de portions pavĂ©es en longeant les murs dâest et dâouest Ă lâextĂ©rieur. Le bĂątiment pourrait appartenir Ă lâancienne rĂ©sidence princiĂšre. Les Ă©lĂ©ments stratigraphiques prouvent lâantĂ©rioritĂ© de cette construction par rapport aux bĂątiments du monastĂšre. La dĂ©couverte, dans une couche de terre ultĂ©rieure Ă la dĂ©saffectation du bĂątiment, dâune monnaie Ă©mise par le roi de Hongrie Vladislav Ier en 1442, appuie lâhypothĂšse selon laquelle le bĂątiment pourrait dater du XIVe siĂšcle en appartenant Ă lâancienne rĂ©sidence princiĂšre. Par les fouilles effectuĂ©es en 2002 et 2003 on a pu complĂ©ter les informations sur un Ă©difice aux gros murs en pierre, dĂ©couvert en 1981, qui a Ă©tĂ© alors datĂ© au XVIIe siĂšcle. Il sâagit dâune construction en pierre et briques, de grandes proportions (approximativement 11 m de largeur), situĂ©e partiellement sous le niveau du terrain de lâintĂ©rieur de lâenceinte et en mĂȘme temps au niveau du sol vers la limite de la terrasse. On a trouvĂ© le seuil et un montant de lâencadrement en pierre de lâentrĂ©e au niveau infĂ©rieur de la bĂątisse. Les donnĂ©es archĂ©ologiques, surtout les observations stratigraphiques, peuvent confirmer la datation initiale de la construction, bien que les informations doivent ĂȘtre complĂ©tĂ©es. Des mentions documentaires ont permis de supposer que cette construction aurait pu abriter les magasins et lâauberge du monastĂšre, construits en 1646â 1647 et dĂ©truits en 1737. On a aussi dĂ©couvert et dĂ©limitĂ© les traces dâune construction monastique datant probablement du XVIIIe siĂšcle. En 2004 et 2005, au sud-est de lâĂ©glise, on a mis Ă jour des traces qui peuvent ĂȘtre attribuĂ©es au mur qui entourait lâĂ©glise, sur son cotĂ© est, et autres qui peuvent appartenir Ă la fortification en terre qui limitait vers le sud lâensemble. On a trouvĂ© les restes des deux murs en angle droit, de plus dâun mĂštre dâĂ©paisseur vers lâest, qui, tenant compte de la position stratigraphique, peuvent dater du XIVe siĂšcle. On a trouvĂ© des traces dâhabitation du XVIe siĂšcle. De nombreux restes des murs appartenant aux constructions monastiques, du XVIIe, XVIIIe et XIXe siĂšcle ont Ă©tĂ© dĂ©couverts. Dans dâautres deux points on a trouvĂ© le mur dâenceinte du monastĂšre de XVIIe siĂšcle, et aussi un mur contemporain, parallĂšle, vers lâouest. Appartenant aux constructions monastiques qui limitaient vers le sud lâenceinte, on a dĂ©couvert deux murs parallĂšles et un pavement en briques entre eux. Les bĂątiments situĂ©s au sud de lâĂ©glise ont fonctionnĂ© jusquâen 1934, quand ils ont Ă©tĂ© dĂ©truits par un grand incendie. Sur une grande surface, au nord de ces murs, se trouvent des couches trĂšs Ă©pais de dĂ©combres, pierre, restes de mortier, qui couvrent aussi les restes des autres murs. Les traces des constructions de diffĂ©rentes pĂ©riodes, Ă cause de lâĂ©tendue limitĂ©e de la surface des fouilles, ont pu ĂȘtre dĂ©couvertes seulement par fragments. Lâimage quâon peut se former sur lâensemble est subjective et incomplĂšte. On peut formuler seulement des hypothĂšses en ce qui concerne le plan et la chronologie des constructions. Une recherche intĂ©grale, qui pourrait donner une image dâensemble sur tous ces vestiges, en confirmant ou en infirmant diverses hypothĂšses serrait possible un jour, si on envisageait la mise en valeur des restes des Ă©difices disparus.Cantacuzino Gheorghe I., RÄdulescu Maria-Venera, TrĂąmbaciu Ćtefan. CercetÄri arheologice la CĂąmpulung, Ăźn zona vechii reĆedinĆŁe domneĆti (2000â2005) / Les fouilles entreprises dans la zone de lâancienne rĂ©sidence princiĂšre de CĂąmpulung (2000â2005). In: Materiale Ći cercetĂŁri arheologice (Serie nouĂŁ), N°2 2007. 2000-2006. pp. 95-141
Existence and Stability of Limit Cycles in a Two-delays Model of Hematopoiesis Including Asymmetric Division
A two dimensional two-delays differential system modeling the dynamics of stem-like cells
and white-blood cells in Chronic Myelogenous Leukemia is considered. All three types of
stem cell division (asymmetric division, symmetric renewal and symmetric differentiation)
are present in the model. Stability of equilibria is investigated and emergence of
periodic solutions of limit cycle type, as a result of a Hopf bifurcation, is eventually
shown. The stability of these limit cycles is studied using the first Lyapunov
coefficient
TOT versus TVT â mesh surgical treatment in stress urinary incontinence
Introduction: Stress urinary incontinence is a highly debilitating condition, with an important impact over the quality of life. When the conservative treatment fails, the surgical treatment is a viable solution. Minimally invasive sling procedures have become the gold standard of surgical management for stress urinary incontinence (SUI) in women.
Material and methods: The study was conducted on 68 patients with stress urinary incontinence, 52 have undergone the retropubic tension-free vaginal tape and 16 patients were operated using the transobturator tape procedure. All the patients were evaluated before the operation and the indication of the surgical treatment was established on the basis of physical examination (all the patients had positive cough test), abdominal ultrasound (to determine postvoid residual urine volume), urinalysis and urine culture (the majority of the patients have had before the operation
recurrent urinary tract infections).
Results: The satisfaction was similar in both groups of patients, with an average satisfaction rate of 91% for TVT and 86% for the patients who have undergone TOT procedure. The patients were in a proportion of 78,9% at menopause, with an average number of natural births of 1.9 and a mean BMI of 28.2. Regarding the surgical duration, this has varied between 20 and 40 minutes, being higher in the TVT cases (up to 5-7 minutes longer than TOT), because cystoscopy was performed during the operation to verify if the bladder was perforated or not. The urethral catheter was removed immediately after the operation in the case of the TOT procedure and in the day after the operation for the patients who have undergone TVT procedures (all of these patients associated genital prolapse). The hospitalization time was 3 days. We havenât encountered significant intraoperative and postoperative complications.
Conclusions: The TOT and TVT procedures have proven to be highly effective and safe methods in the treatment of SUI. There are no significant differences regarding the efficacy of these two
surgical methods, but the risk of intraoperative complications is a little higher for the TVT procedure. The mid urethral sling procedures improve significantly the quality of life for patients
with stress urinary incontinence
Urban electrical vehicles as the solution for public transportation in the cities of Romania
This paper shows that the European Recommendation COM (2007) 551 final finds that over 60% of the population lives in urban areas in the European Union (EU). Urban areas now constitute the living environment of the majority of the population and increased traffic in town and city centers has resulted in chronic congestion. Every year nearly 100 billion Euros, or 1% of the EUâs gross domestic product (GDP), are lost to the European economy as a result of this congestion. The analysis of the means of transport presented in this paper will show which electrical vehicle is the solution for non-polluting transport according to each specific need. The Romanian company ICPE SAERP, together with the Urban Transport Administration of Bucharest (RAT Bucharest), has modernized classic tramcars, equipping them with three-phase inverters and asynchronous motors and a partially lowered floor. By 2011, 18 tramcars will be modernized. ICPE SAERP together with ASTRA BUS Arad, will produce and deliver new trolleybuses with lowered floors in Bucharest. These new trolleybuses will be equipped with three-phase inverters, with asynchronous motors and with converters for the auxiliary services and for the air conditioning system. Also the trolleybus has a protection device against high voltage present on the body of the vehicle, which is controlled by means of a DSP processor in the master controller. The methodology used in the authors research is presented in this paper as well as the results that led to the conclusion that the type of public transportation proposed is cleaner, more reliable, more efficient and more comfortable than others
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