Confined Coulomb systems with absorbing boundaries: the two-dimensional two-component plasma

Using a solvable model, the two-dimensional two-component plasma, we study a Coulomb gas confined in a disk and in an annulus with boundaries that can adsorb some of the negative particles of the system. We obtain explicit analytic expressions for the grand potential, the pressure and the density profiles of the system. By studying the behavior of the disjoining pressure we find that without the adsorbing boundaries the system is naturally unstable, while with attractive boundaries the system is stable because of a positive contribution from the surface tension to the disjoining pressure. The results for the density profiles show the formation of a positive layer near the boundary that screens the adsorbed negative particles, a typical behavior in charged systems. We also compute the adsorbed charge on the boundary and show that it satisfies a certain number of relations, in particular an electro-neutrality sum rule.Comment: 17 pages, 11 figures, v2: section IV was shortened and some formulas has been rewritten to make them more readabl

Spin-harmonic structures and nilmanifolds

We introduce spin-harmonic structures, a class of geometric structures on Riemannian manifolds of low dimension which are defined by a harmonic unitary spinor. Such structures are related to SU(2) (dim=4,5), SU(3) (dim=6) and G_2 (dim=7) structures; in dimension 8, a spin-harmonic structure is equivalent to a balanced Spin(7) structure. As an application, we obtain examples of compact 8-manifolds endowed with non-integrable Spin(7) structures of balanced type.Comment: 34 pages, no figure

Estudi del consum energètic de convertidors analògic-digital integrats en microcontroladors

Microcontrollers are programmable integrated circuits designed to control any particular application. Nowadays are present in many of the electronic devices that surround us: at work, at home and in our life in general. They can be found by controlling the operation of mobiles, computers, tablets, TVs, smart clocks, etc. These are also the main control devices in low-energy sensing nodes applied to smart cities and intelligent buildings. The microcontrollers have integrated hardware modules (called peripherals) in the same chipandthatcanworksimultaneouslywiththeexecutionofinstructionsmadebytheCPU. One of these peripherals is the analog-digital converter (ADC) that has the function of converting an analog input voltage to digital data. This bachelor thesis is intended to study the energy consumption of these integrated ADCs. To do this study, two integrated converters will be presented in different commercial microcontrollers and different experiments will be carried out to measure their consumption. The power consumption of the two ADCs will be studied separately and later a comparison will be made. Finally, conclusions will be drawn on the most appropriate mode of operation (for example, in terms of working frequency of this peripheral) for a lowconsumption ADC conversion that allows, for example, increasing the life time of sensor nodes.Els microcontroladors son circuits integrats programables destinats a governar una apli- ´ cacio determinada. Aquests estan presents en molts dels dispositius electr ´ onics que ens ènvolten: a la feina, a casa nostra i en la nostra vida en general. Es poden trobar controlant el funcionament de mobils, ordinadors, tablets, TV, rellotges intel ` ·ligents, etc. Tambe s ´ onéls dispositius principals de control en nodes sensors de baix consum aplicats a ciutats i edificis intel·ligents. Els microcontroladors disposen de recursos hardware (anomenats periferics) integrats en èl mateix xip i que poden funcionar simultaniament amb l’execuci ` o d’instruccions feta per ´ la CPU. Un d’aquests periferics ` es el convertidor anal ´ ogic-digital (ADC) que t ` e la funci ´ o´ de convertir una tensio d’entrada anal ´ ogica en una dada digital. ` Aquest treball de final de grau esta destinat a estudiar el consum energ ` etic d’aquests ` ADC integrats. Per fer aquest estudi, es presentaran dos convertidors integrats en diferents microcontroladors comercials i es realitzaran diferents experiments per mesurar el seu consum. S’estudiara el consum d’energia dels dos convertidors ADC per separat i ` posteriorment es fara una comparativa. Finalment s’extrauran conclusions sobre el mode ` de funcionament mes adequat (per exemple, en quant a la freq ´ u¨encia de treball) per ob- ` tenir una conversio ADC de baix consum que permeti, per exemple allargar el temps de ´ vida de nodes sensor

Ácido úrico y pcr de pacientes en terapia de reemplazo renal crónico en la unidad renal del Hospital Militar Central

Los estudios epidemiológicos han sugerido el papel independiente de la hiperuricemia en aumentó de la mortalidad, la enfermedad cardiovascular ( ECV ), y enfermedad renal en la población general. Sin embargo, datos publicados sobre la ERC en hemodiálisis es limitada e inconsistente. La hiperuricemia es altamente prevalente en la ERC, lo que podría explicar la disminución de la excreción renal de ácido úrico en la disminución de la función renal y la asociación de la hiperuricemia con diversos factores de riesgo de ERC, como la hipertensión y la diabetes mellitus, en la ERC en hemodiálisis, no está claro si el acido úrico es meramente un marcador que refleja la integración de los Comorbilidades y el daño renal o un verdadero causante del riesgo y muerte.Epidemiological studies have suggested the independent role of hyperuricemia in increased mortality, cardiovascular disease (CVD), and renal disease in the general population. However, published data on CKD on hemodialysis is limited and inconsistent. Hyperuricemia is highly prevalent in CKD, which could explain the decreased renal excretion of uric acid in the decline of renal function and the association of hyperuricemia with various CKD risk factors such as hypertension and diabetes mellitus in CKD on hemodialysis, it is unclear whether uric acid is merely a marker that reflects the integration of Comorbidities and kidney damage or a real risk causing death

Shapes of clusters and groups of galaxies: Comparison of model predictions with observations

We study the properties of the 3-dimensional and projected shapes of haloes using high resolution numerical simulations and observational data where the latter comes from the 2PIGG (Eke et al. 2004) and SDSS-DR3GC group catalogues (Merchan & Zandivarez 2005). We investigate the dependence of halo shape on characteristics such as mass and number of members. In the 3-dimensional case, we find a significant correlation between the mass and halo shape; massive systems are more prolate than small haloes. We detect a source of strong systematics in estimates of the triaxiality of a halo, which is found to be a strong function of the number of members; LCDM haloes usually characterised by triaxial shapes, slightly bent toward prolate forms, appear more oblate when taking only a small subset of the halo particles. The ellipticities of observed 2PIGG and SDSS-DR3GC groups are found to be strongly dependent on the number of group members, so that poor groups appear more elongated than rich ones. However, this is again an artifact caused by poor statistics and not an intrinsic property of the galaxy groups, nor an effect from observational biases. We interpret these results with the aid of a GALFORM mock 2PIGG catalogue. When comparing the group ellipticities in mock and real catalogues, we find an excellent agreement between the trends of shapes with number of group members. When carefully taking into account the effects of low number statistics, we find that more massive groups are consistent with more elongated shapes. Finally, our studies find no significant correlations between the shape of observed 2PIGG or SDSS-DR3GC groups with the properties of galaxy members such as colour or spectral type index.Comment: 9 pages, 10 figures, submitted to MNRA

The treatment of patellar tendinopathy

BACKGROUND: Patellar tendinopathy (PT) presents a challenge to orthopaedic surgeons. The purpose of this review is to revise strategies for treatment of PT MATERIALS AND METHODS: A PubMed (MEDLINE) search of the years 2002–2012 was performed using "patellar tendinopathy" and "treatment" as keywords. The twenty-two articles addressing the treatment of PT with a higher level of evidence were selected. RESULTS: Conservative treatment includes therapeutic exercises (eccentric training), extracorporeal shock wave therapy (ESWT), and different injection treatments (platelet-rich plasma, sclerosing polidocanol, steroids, aprotinin, autologous skin-derived tendon-like cells, and bone marrow mononuclear cells). Surgical treatment may be indicated in motivated patients if carefully followed conservative treatment is unsuccessful after more than 3–6 months. Open surgical treatment includes longitudinal splitting of the tendon, excision of abnormal tissue (tendonectomy), resection and drilling of the inferior pole of the patella, closure of the paratenon. Postoperative inmobilisation and aggressive postoperative rehabilitation are also paramount. Arthroscopic techniques include shaving of the dorsal side of the proximal tendon, removal of the hypertrophic synovitis around the inferior patellar pole with a bipolar cautery system, and arthroscopic tendon debridement with excision of the distal pole of the patella. CONCLUSION: Physical training, and particularly eccentric training, appears to be the treatment of choice. The literature does not clarify which surgical technique is more effective in recalcitrant cases. Therefore, both open surgical techniques and arthroscopic techniques can be used

La classe renversée en formation des enseignants pour mobiliser les étudiants

Comprend des références bibliographiquesUne expérimentation de classe renversée en contexte de formation de futurs professeurs des écoles dans le cadre d’un module de sciences expérimentales et technologie a été menée. Si le but de la mise en place de cette démarche pédagogique était de faire construire le cours aux étudiants, son mobile était de mobiliser les étudiants dans la ré-activation de leurs propres connaissances dans le domaine scientifique et technologique, les contenus ayant déjà été rencontrés par les étudiants au cours de leur parcours scolaire. L’observation des étudiants lors du travail de groupe et leurs réponses aux questionnaires montrent qu’il y a eu coopération et collaboration dans la construction du cours. En revanche, rien ne met en avant l’acquisition de l’ensemble des notions constitutives du cours. La classe renversée apparaît comme une alternative intéressante au cours magistral. L’impact du dispositif sur le rapport aux savoirs et au métier mériterait d’être développé