572 research outputs found

    Aspects of open-flavour mesons in a comprehensive DSBSE study

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    Open-flavour meson studies are the necessary completion to any comprehensive investigation of quarkonia. We extend recent studies of quarkonia in the Dyson-Schwinger-Bethe-Salpeter-equation approach to explore their results for all possible flavour combinations. Within the inherent limitations of the setup, we present the most comprehensive results for meson masses and leptonic decay constants currently available and put them in perspective with respect to experiment and other approaches.Comment: 38 pages, 26 figures, 2 tables, revised according to reviewer comment

    Form factors of heavy-light systems in point-form relativistic quantum mechanics: the Isgur-Wise function

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    We investigate electromagnetic and weak form factors of heavy-light mesons in the context of point-form relativistic quantum mechanics. To this aim we treat the physical processes from which such electroweak form factors are extracted by means of a coupled channel approach which accounts for the dynamics of the intermediate gauge bosons. It is shown that heavy-quark symmetry is respected by this formulation. A simple analytical expression is obtained for the Isgur-Wise function in the heavy-quark limit. Breaking of heavy-quark symmetry due to realistic values of the heavy-quark mass are studied numerically.Comment: Presented at the 21st European Conference on Few-Body Problems in Physics, Salamanca, Spain, 30 August - 3 September 201

    Design and simulation of metropolitan urban growth demands scenarios

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    La generación y simulación de escenarios exploratorios externos es un instrumento útil en los procesos de planificación y toma de decisiones, de especial relevancia en el ámbito territorial y metropolitano (Peterson et al, 2003; Pettit y Pullar, 2004; Luca, 2007; Carsjens, 2009), cuyo calado en el proceso de planificación en España es escaso hasta la fecha (Valenzuela, Aguilera, Soria y Molero, 2008). En este artículo se presenta un modelo basado en Dinámica de Sistemas para estimar las demandas de nuevo suelo urbano en ámbitos metropolitanos. El modelo se ha desarrollado concretamente para dos ámbitos metropolitanos españoles (Región Urbana de Madrid y Aglomeración Urbana de Granada) para los cuales se ha realizado un proceso de calibración individual, Una vez calibrado el modelo para dichos ámbitos, y a través del planteamiento de tres escenarios futuros, se han simulado las posibles tendencias de las demandas de ocupación urbana que podrían derivarse de las premisas establecidas en cada escenario, con unos resultados satisfactorios. Dichos resultados podrán ser empleados en otros trabajos que permitirán localizar espacialmente, mediante modelos de simulación espacial, las demandas estimadas, para mostrar y evaluar posibles consecuencias espaciales y territoriales de los procesos de crecimiento metropolitano.The design and development of future explorative external scenarios are useful tools for the spatial planning and even more for the metropolitan planning (Peterson et al, 2003; Pettit y Pullar, 2004; Luca, 2007; Carsjens, 2009). However, spatial planning policy and practices in Spain lack of this instruments (Valenzuela, Aguilera, Soria y Molero, 2008) This paper shows a System Dynamics-based model designed to estimate urban growth demands in metropolitan areas. This model has been specifically developed for Madrid and Granada metropolitan areas (Spain), where the model has been calibrated. After the calibration, three future urban growth demands scenarios has been designed and simulated using the model developed. The urban growth demands obtained may be used in later research to spatially locate that demands using spatial simulation models.Peer Reviewe

    Aportación de la densitometría ósea en las artroplastias de rodilla

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    El presente trabajo consiste en una revisión clínica y radiológica de 84 artroplastias modulares de rodilla de las cuales, en 19 se ha estudiado la masa ósea periprotésica (7 cementadas y 12 sin cementar) antes, al mes y a los seis meses de la intervención mediante un densitómetro de doble fotón. Aparte, se ha probado la correlación directa entre la indicación peroperatoria de no cementar y una mayor masa ósea en todas las zonas periprotésicas; por otro lado, se ha observado una diferente distribución de la densidad mineral ósea en la tibia tras la intervención, según se haya utilizado o no cemento. Estos hallazgos confirman el estudio densitométrico previo a la intervención como un método complementario útil en la indicación de la cementación de la artroplastia total de rodilla.A clinical and radiological revision of 84 modular knee arthroplasties is presented. Periprosthesis bone mineral content was studied in 19 prostheses (7 cemented and 12 uncemented) before, surgery one and 6 months after the intervention using a densitometer of double energy. A direct correlation between the implantation of a non-cemented prosthesis and the growth of the bone mass in all the periprosthesis areas was found, existing a different distribution of the mineral bone density of the tibia after the intervention depending on the use of cement. These findings show that the densitometric study previous to an intervention as a useful complementary method in the indication of cemented total knee arthroplasty

    The Globular Cluster System of NGC4374

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    We study the globular cluster system (GCS) of the giant elliptical NGC4374 (M84) in the Virgo cluster using B and R photometry. The colour distribution is bimodal with peaks at B-R=1.11 and B-R=1.36, fitting well to those found in other early-type galaxies. The radial profile of the cluster number density is flatter than the galaxy light. Using the luminosity function we derive a distance modulus of μ=31.61±0.2\mu=31.61\pm0.2, which within the uncertainty agrees with the distance from surface brightness fluctuations. Blue and red clusters show similar radial concentrations and azimuthal distributions. The total number of clusters is N=1775±150N=1775\pm150, which together with our distance modulus leads to a specific frequency of SN=1.6±0.3S_{N}=1.6\pm0.3. This value is surprisingly low for a giant elliptical, but resembles the case of merger remnants like NGC1316, where the low specific frequency is probably caused by the luminosity contribution of an intermediate-age population. A further common property is the high rate of type Ia supernovae which also may indicate the existence of a younger population. However, unlike in the case of NGC1316, one cannot find any further evidence that NGC4374 indeed hosts younger populations. The low specific frequency would also fit to a S0 galaxy seen face-on.Comment: Accepted for publication in Astronomy & Astrophysics. 11 page

    Occurrence of antibiotics and bacterial resistance in wastewater and sea water from the Antarctic

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    The potential presence of introduced antibiotics in the aquatic environment is a hot topic of concern, particularly in the Antarctic, a highly vulnerable area protected under the Madrid protocol. The increasing presence of human population, especially during summer, might led to the appearance of pharmaceuticals in wastewater. The previous discovery of Escherichia coli strains resistant to antibiotics in sea water and wastewater collected in King George Island motivated our investigation on antibiotics occurrence in these samples. The application of a multi-residue LCMS/MS method for 20 antibiotics, revealed the presence of 8 compounds in treated wastewater, mainly the quinolones ciprofloxacin and norfloxacin (92% and 54% of the samples analyzed, average concentrations 0.89 μg/L and 0.75 μg/L, respectively) and the macrolides azithromycin and clarithromycin (15% positive samples, and average concentrations near 0.4 μg/L), and erythromycin (38% positive samples, average concentration 0.003 μg/L). Metronidazole and clindamycin were found in one sample, at 0.17 and 0.1 μg/L, respectively; and trimethoprim in two samples, at 0.001 μg/L. Analysis of sea water collected near the outfall of the wastewater discharges also showed the sporadic presence of 3 antibiotics (ciprofloxacin, clindamycin, trimethoprim) at low ng/L level, illustrating the impact of pharmaceuticals consumption and the poor removal of these compounds in conventional WWTPs. The most widespread antibiotic in sea water was ciprofloxacin, which was found in 15 out of 34 sea water samples analyzed, at concentrations ranging from 4 to 218 ng/L. Bacteria resistance was observed for some antibiotics identified in the samples (e.g. trimetropim and nalidixic acid –a first generation quinolone). However, resistance to some groups of antibiotics could not be correlated to their presence in the water samples due to analytical limitations (penicillins, tetraciclines). On the contrary, for some groups of antibiotics detected in samples (macrolides), the antibacterial activity against E. Coli was not investigated because these antibiotics do not include this bacterial species in their spectrum of activity. Our preliminary data demonstrate that antibiotics occurrence in the Antarctic aquatic environment is an issue that needs to be properly addressed. Periodical monitoring of water samples and the implementation of additional treatments in the WWTPs are recommended as a first step to prevent potential problems related to the presence of antibiotics and other emerging contaminants in the near future in Antarctica

    Experiencia a medio plazo con prótesis total de rodilla semiconstreñida

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    Revisamos 25 prótesis totales de rodilla semiconstreñidas tipo Endo-Model Waldemar- Link implantadas en 23 pacientes con una edad media de 69,5 años y un seguimiento medio de 32 meses. Para la evaluación de los resultados clínicos hemos utilizado el protocolo de la Academia Americana en el que se incluyen los parámetros de: dolor, capacidad para la marcha, facilidad para subir y bajar escaleras, necesidad o no de bastones y flexoextensión de la articulación, tanto antes como después de la intervención. Asimismo hemos realizado un estudio radiológico de las prótesis en el que se ha valorado el centraje de los componentes protésicos en dos planos AP y L y las imágenes líticas periprotésicas. Los resultados obtenidos han sido satisfactorios observando en la totalidad de los pacientes una disminución del dolor y un aumento de su capacidad funcional. En ningún caso se han observado infecciones profundas de la prótesis. Se ha comprobado un aumento en el arco de flexión en las prótesis en que la punta del vástago femoral estaba desviada hacia la cortical anterior, sin que esto se acompañase de un déficit en la extensión.We have reviewed 25 total knee prosthesis (Endo-Model type, Waldemar-Link) performed in 23 patients with an age average of 69,5 years-old and a average follow-up of 32 months. The clinical assessment applied was the AAOS protocol including the parameters of: pain, ability to go up and down the stairs, to need of sticks, flexion and extension of the joint, before and after the operation. In the radiological study we have evaluated the correct alignment of the components in two planes A-P and L, and the periprosthetic lucencies. The results obtained have been satisfying in all the patients with a diminution of the pain and better function of the joint. No deep infection was observed and the flexion was better in prosthesis with anterior deviation of the femoral rod in the lateral plane

    Biosensors to diagnose Chagas disease: A review

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    International audienceChagas disease (CD), which mostly affects underprivileged people, has turned into one 9 of Latin America's main public health problems. Prevention of the disease requires early diagnosis, 10 initiation of therapy, and regular blood monitoring of the infected individual. However, the majority 11 of the infections go undiagnosed because of general mild symptoms and lack of access to medical 12 care. Therefore, more affordable and accessible detection technologies capable of providing early 13 diagnosis and parasite load measurements in settings where CD is prevalent are needed to enable 14 enhanced intervention strategies. This review discusses currently available detection technologies 15 and emerging biosensing technologies for a future application to CD. Even if biosensing 16 technologies still require further research efforts to develop portable systems, we arrive to the 17 conclusion that biosensors could improve diagnosis and the patients' treatment follow-up, in terms 18 of rapidity, small sample volume, high integration, ease of use, real-time and low cost detection 19 compared to current conventional technologies. 2

    Enhanced proliferation of pre-osteoblastic cells by dynamic piezoelectric stimulation

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    [EN] This work reports on the influence of the polarization of electroactive poly(vinylidene fluoride), PVDF, on the biological response of cells cultivated under static and dynamic conditions. Non-poled and "poled +" beta-PVDF with and without a titanium layer were thus prepared. A thin titanium layer was deposited on PVDF films in order to obtain a more homogeneous surface charge. The MC3T3-E1 osteoblast cell culture exhibited different responses in the presence of PVDF films. The positively charged beta-PVDF films promote higher osteoblast adhesion and proliferation, which is higher under dynamic conditions on poled samples, showing that the surface charge under mechanical stimulation improves the osteoblast growth. Therefore, electroactive membranes and scaffolds can provide the necessary electrical stimuli for the growth and proliferation of specific cells.JLGR acknowledge the support of the Spanish Ministry of Education through project No. MAT2010-21611-C03-01 (including the FEDER financial support) and project EUI2008-00126.Ribeiro, C.; Moreira, S.; Correia, V.; Sencadas, V.; Rocha, JG.; Gama, FM.; Gómez Ribelles, JL.... (2012). Enhanced proliferation of pre-osteoblastic cells by dynamic piezoelectric stimulation. RSC Advances. 2(30):11504-11509. https://doi.org/10.1039/c2ra21841k115041150923

    Form Factors of Few-Body Systems: Point Form Versus Front Form

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    We present a relativistic point-form approach for the calculation of electroweak form factors of few-body bound states that leads to results which resemble those obtained within the covariant light-front formalism of Carbonell et al. Our starting points are the physical processes in which such form factors are measured, i.e. electron scattering off the bound state, or the semileptonic weak decay of the bound state. These processes are treated by means of a coupled-channel framework for a Bakamjian-Thomas type mass operator. A current with the correct covariance properties is then derived from the pertinent leading-order electroweak scattering or decay amplitude. As it turns out, the electromagnetic current is affected by unphysical contributions which can be traced back to wrong cluster properties inherent in the Bakamjian-Thomas construction. These spurious contributions, however, can be separated uniquely, as in the covariant light-front approach. In this way we end up with form factors which agree with those obtained from the covariant light-front approach. As an example we will present results for electroweak form factors of heavy-light systems and discuss the heavy-quark limit which leads to the famous Isgur-Wise function.Comment: Presented at LIGHTCONE 2011, Dallas, USA, 23 - 27 May, 201
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