Relative Navigation Strategy About Unknown and Uncooperative Targets

In recent years, space debris has become a threat for satellites operating in low Earth orbit. Even by applying mitigation guidelines, their number will still increase over the course of the century. As a consequence, active debris removal missions and on-orbit servicing missions have gained momentum at both academic and industrial level. The crucial step in both scenarios is the capability of navigating in the neighborhood of a target resident space object. This problem has been tackled many times in literature with varying level of cooperativeness of the target required. While several techniques are available when the target is cooperative or its shape is known, no approach is mature enough to deal with uncooperative and unknown targets. This paper proposes a hybrid method to tackle this issue called Coarse Model-Based Relative Navigation (CoMBiNa). The main idea of this algorithm is to split the mission into two phases. During the first phase, the algorithm constructs a coarse model of the target. In the second phase, this coarse model is used as a reference for a relative navigation technique, effectively shifting the focus toward state and inertia estimation. In addition, this paper proposes a strategy to leverage the structure of the selected navigation method to detect and reject outliers. To conclude, CoMBiNa is tested on a simulated environment to highlight its benefits and its shortcomings, while also assessing its applicability on a limited-resource single-board computer

Tri-bimaximal Neutrino Mixing and Quark Masses from a Discrete Flavour Symmetry

We build a supersymmetric model of quark and lepton masses based on the discrete flavour symmetry group T', the double covering of A_4. In the lepton sector our model is practically indistinguishable from recent models based on A_4 and, in particular, it predicts a nearly tri-bimaximal mixing, in good agreement with present data. In the quark sector a realistic pattern of masses and mixing angles is obtained by exploiting the doublet representations of T', not available in A_4. To this purpose, the flavour symmetry T' should be broken spontaneously along appropriate directions in flavour space. In this paper we fully discuss the related vacuum alignment problem, both at the leading order and by accounting for small effects coming from higher-order corrections. As a result we get the relations: \sqrt{m_d/m_s}\approx |V_{us}| and \sqrt{m_d/m_s}\approx |V_{td}/V_{ts}|.Comment: 27 pages, 1 figure; minor correction

On Vertex- and Empty-Ply Proximity Drawings

We initiate the study of the vertex-ply of straight-line drawings, as a relaxation of the recently introduced ply number. Consider the disks centered at each vertex with radius equal to half the length of the longest edge incident to the vertex. The vertex-ply of a drawing is determined by the vertex covered by the maximum number of disks. The main motivation for considering this relaxation is to relate the concept of ply to proximity drawings. In fact, if we interpret the set of disks as proximity regions, a drawing with vertex-ply number 1 can be seen as a weak proximity drawing, which we call empty-ply drawing. We show non-trivial relationships between the ply number and the vertex-ply number. Then, we focus on empty-ply drawings, proving some properties and studying what classes of graphs admit such drawings. Finally, we prove a lower bound on the ply and the vertex-ply of planar drawings.Comment: Appears in the Proceedings of the 25th International Symposium on Graph Drawing and Network Visualization (GD 2017

Lepton Flavour Violation in a Supersymmetric Model with A4 Flavour Symmetry

We compute the branching ratios for mu-> e gamma, tau-> mu gamma and tau -> e gamma in a supersymmetric model invariant under the flavour symmetry group A4 X Z3 X U(1)_{FN}, in which near tri-bimaximal lepton mixing is naturally predicted. At leading order in the small symmetry breaking parameter u, which is of the same order as the reactor mixing angle theta_{13}, we find that the branching ratios generically scale as u^2. Applying the current bound on the branching ratio of mu -> e gamma shows that small values of u or tan(beta) are preferred in the model for mass parameters m_{SUSY} and m_{1/2} smaller than 1000 GeV. The bound expected from the on-going MEG experiment will provide a severe constraint on the parameter space of the model either enforcing u approx 0.01 and small tan(beta) or m_{SUSY} and m_{1/2} above 1000 GeV. In the special case of universal soft supersymmetry breaking terms in the flavon sector a cancellation takes place in the amplitudes and the branching ratios scale as u^4, allowing for smaller slepton masses. The branching ratios for tau -> mu gamma and tau -> e gamma are predicted to be of the same order as the one for mu -> e gamma, which precludes the possibility of observing these tau decays in the near future.Comment: 44 page

Tratamiento del ardor bucal y de la boca seca. Nuevas tendencias

En la presente revisión, abordaremos el tratamiento del SBA. Dado que desconocemos con exactitud la etiopa-togenia, el tratamiento suele orientarse hacia el manejo de los síntomas. Se pretende: Tratar los procesos relacionados con ardor bucal eliminando los factores locales o irritantes (tabaco, alcohol, comidas picantes y bebidas ácidas, aristas cortantes, xerostomía, disgeusia, parafunciones, bruxismo, mordisqueo o succión de mucosas, hábitos parafuncionales orales, irritación mecánica, prótesis desajustadas o alergia a materiales denta-les) ya que estos pueden aumentan el ardor. Prevenir y tratar alteraciones o lesiones sobre la mucosa bucal. Por otro lado se deben tratar y/o remitir procesos psicopatológicos. El hecho de escuchar con atención al paciente y explicarle el motivo de sus molestias suele calmar al paciente y disminuir los síntomas por lo que se aconseja una evaluación de forma periódica cada 6 meses. El tratamiento se basa en cuatro posibilidades terapéuticas: Odontológico: local-conservador e higiénico (pulir-redondear cúspides o aristas cortantes; realizar tratamiento protésico, la utilización de barreras físicas como geles o protectores dentales); Farmacológicos, Psicológicos: la depresión y la ansiedad desempeñan un papel importante en la modulación de la percepción del dolor, se han evidenciado en estos pacientes alteraciones del sistema nervioso central y del sistema nervioso periférico por lo que el uso de fármacos psicoactivos antidepresivos se han justificado, entre ellos el clonacepam tópico (Rivotril®), con una mejoría del 50% de los síntomas. Dados los escasos resultados obtenidos en el tratamiento del cuadro, se han propuesto una serie de tratamientos Alternativos para intentar controlarlo, los cuales han tenido aparen-tes resultados beneficiosos: infrarrojos, el láser de baja intensidad aplicado en la zona referida por el paciente, la fitoterapia con efectos analgésicos y antidepresivos, con mejoría del 52% de los pacientes, el aloe vera, la acupuntura y el tratamiento cognitivo-conductual que ayuda a reducir la ansiedad. Teniendo en cuenta que ninguno de los tratamientos es definitivo ni universal, podemos concluir que existen tratamientos eficaces para algunos de los casos, pero en otros muchos se sigue buscando un procedimiento que resulte eficaz

Susceptibility of Candida glabrata biofilms to echinocandins: alterations in the matrix composition

Candidiases are the most recurrent fungal infections, especially among immunosuppressed patients. Although Candida albicans is still the most widespread isolated species, non-Candida albicans Candida species have been increasing. The goal of this work was to determine the susceptibility of C. glabrata biofilms to echinocandins and to evaluate their effect on the biofilm matrix composition, comparing the results with other Candida species. Drug susceptibilities were assessed through the determination of minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC) and minimum biofilm eradication concentration (MBEC) of caspofungin (Csf) and micafugin (Mcf). The -1,3 glucans content of the matrices was assessed after contact with the drugs. The data suggest that, generally, after contact with echinocandins, the concentration of -1,3 glucans increased. These adjustments in the matrix composition of C. glabrata biofilms and the chemical differences between Csf and Mcf, seem responsible and may determine the effectivity of the drug responses.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 [POCI-01–0145-FEDER-006684] and BioTecNorte operation [NORTE-01–0145-FEDER-000004] funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte, Célia F. Rodrigues’ [SFRH/BD/93078/2013] PhD grant and M. Elisa Rodrigues [SFRH/BPD/95401/2013] post-doctoral grant.info:eu-repo/semantics/publishedVersio

Burning mouth syndrome and associated factors: A case-control retrospective study

Podeu consultar la versió en anglès a: http://hdl.handle.net/2445/113324Antecedentes y objetivo: El síndrome de boca ardiente (SBA) puede definirse como ardor o disestesia en la lengua y/u otras áreas de la mucosa bucal, en ausencia de lesiones que puedan justificarlo. Su incidencia es mayor en pacientes de sexo femenino, de edades comprendidas entre 50 y 60 años. Estas molestias suelen recurrir diariamente, provocando un deterioro de la calidad de vida. El objetivo del estudio fue evaluar la asociación entre diversos factores patogénicos y el SBA. Pacientes y métodos: Se estudiaron de forma retrospectiva 736 historias clínicas de pacientes diagnosticados de SBA y 132 historias clínicas de pacientes control. El período de estudio se extendió desde enero de 1990 a diciembre de 2014. El protocolo incluyó: sexo, edad, tipo de molestia bucal y localización, entre otras variables. Resultados: El análisis de la asociación entre los factores patogénicos y el diagnóstico de SBA mostró significación estadística en solo 3 de ellos: factores desencadenantes (p = 0,003), hábitos parafuncionales (p = 0,006) e higiene oral (p = 0,012). No se encontraron diferencias significativas en la incidencia del SBA por sexos (p = 0,408), ni asociación entre el SBA y los factores de abuso de sustancias (p = 0,915), patología sistémica (p = 0,685) y hábitos alimentarios (p = 0,904). Conclusiones: Los hábitos parafuncionales como el bruxismo y los movimientos anormales de la lengua y labios pueden explicar la sintomatología del SBA. Hay que tener siempre en cuenta los aspectos psicológicos y los factores sistémicos. Como alteración de carácter multifactorial que es, el tratamiento del SBA debe enfocarse de manera holística