Frustration free gapless Hamiltonians for Matrix Product States

For every Matrix Product State (MPS) one can always construct a so-called parent Hamiltonian. This is a local, frustration free, Hamiltonian which has the MPS as ground state and is gapped. Whenever that parent Hamiltonian has a degenerate ground state (the so-called non-injective case), we construct another 'uncle' Hamiltonian which is local and frustration free but gapless, and its spectrum is $\R^+$. The construction is obtained by linearly perturbing the matrices building up the state in a random direction, and then taking the limit where the perturbation goes to zero. For MPS where the parent Hamiltonian has a unique ground state (the so-called injective case) we also build such uncle Hamiltonian with the same properties in the thermodynamic limit.Comment: 36 pages, new version with some contents rearranged, and a correction in the injective cas

Gapless Hamiltonians for the toric code using the PEPS formalism

We study Hamiltonians which have Kitaev's toric code as a ground state, and show how to construct a Hamiltonian which shares the ground space of the toric code, but which has gapless excitations with a continuous spectrum in the thermodynamic limit. Our construction is based on the framework of Projected Entangled Pair States (PEPS), and can be applied to a large class of two-dimensional systems to obtain gapless "uncle Hamiltonians".Comment: 8 pages, 2 figure

Structural, electronic and magnetic properties of Ti-doped polar and nonpolar GaN surfaces

Based on density functional theory, first-principles calculations were performed in order to study the titanium incorporation on polar and nonpolar GaN surfaces. The formation energy calculations indicate that Ti impurity atoms prefer to incorporate in surface layers (first and second) of GaN. It is also concluded that the incorporation of Ti atoms in Ga-substitutional sites are more energetically favorable compared with N-substitutional or interstitial sites on the polar and nonpolar GaN surfaces. For Ti-rich growth conditions, formation energy calculations show the formation of TixN layers on the a and c GaN surfaces, which corroborates recent experimental observations. Results also display that the 3d-Ti states are the responsible for the metallization of the surface on the c and m planes, forming an intermetallic alloy (TixN), which could be used as low-resistance ohmic contacts for GaN. In addition, the magnetic properties with Ti doping show magnetization of about 1.0 μB/Ti atom for the nonpolar GaN surfaces

LIGHT/HVEM/LTβR Interaction as a Target for the Modulation of the Allogeneic Immune Response in Transplantation

[EN] The exchange of information during interactions of T cells with dendritic cells, B cells or other T cells regulates the course of T, B and DC-cell activation and their differentiation into effector cells. The tumor necrosis factor superfamily member LIGHT (homologous to lymphotoxin, exhibits inducible expression and competes with HSV glycoprotein D for binding to herpesvirus entry mediator, a receptor expressed on T lymphocytes) is transiently expressed upon T cell activation and modulates CD8 T cell-mediated alloreactive responses upon herpes virus entry mediator (HVEM) and lymphotoxin β receptor (LTβR) engagement. LIGHT-deficient mice, or WT mice treated with LIGHT-targeting decoy receptors HVEM-Ig, LTβR-Ig or sDcR3-Ig, exhibit prolonged graft survival compared to untreated controls, suggesting that LIGHT modulates the course and severity of graft rejection. Therefore, targeting the interaction of LIGHT with HVEM and/or LTβR using recombinant soluble decoy receptors or monoclonal antibodies represent an innovative therapeutic strategy for the prevention and treatment of allograft rejection and for the promotion of donor-specific tolerance. This review discusses how targeting the interaction of LIGHT with HVEM and/or LTbR using recombinant soluble decoy receptors or monoclonal antibodies may represent an innovative therapeutic intervention for the prevention and treatment of allograft rejection and promotion of donor-specific tolerance. © 2013 The American Society of Transplantation and the American Society of Transplant SurgeonsSIThis work has been supported by grants FIS reference # PI10/01039 from Ministry of Health and Department of Education from Junta of Castilla and Leon reference # LE007A10-2 (to JIRB), and by the Swiss National Science Foundation (to PS

Mice carrying an epithelial deletion of the glucocorticoid receptor NR3C1 develop a higher tumor load in experimental colitis associated cancer

The glucocorticoid receptor NR3C1 is expressed in multiple cell types in the gut and elsewhere. Intestinal epithelial cells both produce and respond to glucocorticoids in different physiological and pathological contexts. In experimental colitis glucocorticoids have been shown to exert a dual role, dampening inflammation while producing a deterioration in animal status, including death. Mice with tamoxifen inducible, intestinal epithelial specific deletion of NR3C1 (NR3C1IEC mice) are protected against experimental colitis, suggesting glucocorticoid epithelial actions are deleterious. Since glucocorticoids modulate epithelial proliferation it follows that they may affect the development of colon cancer. In this study we set out to test this hypothesis using the dextran sulfate sodium - azoxymethane model of colitis-associated cancer. KO mice were found to exhibit a 2-fold higher tumor load but similar incidence and tumor size. Tumors had a higher trend to extend to the submucosal layer (36% vs. 0%) in NR3C1IEC mice, and overexpressed Lgr5, Egfr and Myc, consistent with increased proliferation and neoplastic transformation. Snai1 and Snai2 were upregulated specifically in tumors of NR3C1ΔIEC mice, suggesting enhanced epithelial to mesenchymal transition in the absence of the intestinal epithelial GC receptor. We conclude that endogenous GC epithelial signaling is involved in colitis associated cancer.This work was supported by funds from the Ministry of Economy and Competitivity, partly with Fondo Europeo de Desarrollo Regional (FEDER) funds [SAF2017-88457-R, AGL2017-85270-R, BFU2014-57736-P, AGL2014-58883-R] and by Junta de Andalucía [CTS235, CTS164]. MA and CJA were supported by the University of Granada (Contrato Puente Program - Plan Propio) and the Ministry of Education [Spain], respectively. CIBERehd is funded by Instituto de Salud Carlos III

In vitro characterization of solute transport in the spinal canal

This paper presents results of an experimental investigation of solute transport in a simplified model of the spinal canal. The work aims to provide increased understanding of the mechanisms responsible for drug dispersion in intrathecal drug delivery (ITDD) procedures. The model consists of an annular channel bounded externally by a rigid transparent tube of circular section, representing the dura mater, and internally by an eccentric cylindrical compliant insert, representing the spinal cord. The tube, closed at one end, is connected to a rigid acrylic reservoir, representing the cranial cavity. The system is filled with water, whose properties are almost identical to those of the cerebrospinal fluid. A programmable peristaltic pump is employed to generate oscillatory motion at frequencies that are representative of those induced by the cardiac and respiratory cycles. Laser induced fluorescence is used to characterize the dispersion of fluorescent dye along the canal and into the cranial cavity for different values of the relevant Womersley number and different eccentricities of the annular section. The present work corroborates experimentally, for the first time, the existence of a steady bulk flow, associated with the mean Lagrangian motion, which plays a key role in the transport of the solute along the spinal canal. The measurements of solute dispersion are found to be in excellent agreement with theoretical predictions obtained using a simplified transport equation derived earlier on the basis of a two-timescale asymptotic analysis. The experimental results underscore the importance of the eccentricity and its variations along the canal and identifies changes in the flow topology associated with differences in the Womersley number, with potential implications in guiding future designs of ITDD protocols.This work was supported by the coordinated project, PID2020-115961RB-C31, PID2020-115961RB-C32, and PID2020-115961RA-C33, financed by MCIN/AEI/10.13039/501100011033, and by the Junta de Andalucia and European Funds, Project No. P18-FR-4619. F. Moral-Pulido wants to thank the Spanish Ministry of Universities for the financial support provided by the Fellowship FPU18/05694. The work of A. L. Sánchez was supported by the U.S. National Science Foundation through Grant No. 1853954

The ongoing volcanic eruption of El Hierro, Canary Islands

El Hierro, the youngest of the Canary Islands (Spain), is no stranger to hazards associated with volcanic activity or to efforts to minimize the effects of these hazards on local communities. As early as 1793, administrative records of El Hierro indicate that a swarm of earthquakes was felt by locals; fearing a greater volcanic catastrophe, the first evacuation plan of an entire island in the history of the Canaries was prepared. The 1793 eruption was probably submarine with no appreciable consequences other than that the earthquakes were felt [Carracedo, 2008]; over the next roughly 215 years the island was seismically quiet. Yet seismic and volcanic activity are expected on this youngest Canary Island due to its being directly above the presumed location of the Canary Island hot spot, a mantle plume that feeds upwelling magma just under the surface, similar to the Hawaiian Islands. Because of this known geologic activity, the Spanish Instituto Geogrfco Nacional (IGN) has managed geophysical monitoring of the island since the beginning of the 1990s.Peer Reviewe

Detección de pacientes con riesgo de desarrollar diabetes en farmacias comunitarias de Pontevedra

OBJETIVO: Evaluar la utilidad del test de findrisk en la farmacia comunitaria para la detección de personas en riego de padecer diabetes tipo 2 en la provincia de Pontevedra. METODOLOGÍA: Estudio descriptivo transversal. Pilotaje de un proyecto con diseño similar que se realizará con ámbito estatal. Ámbito y población de estudio: mayores de 18 años no diagnosticados de diabetes y/o sin tratamiento hipoglucemiante, usuarios durante el mes de enero de 2013 de trece farmacias en Pontevedra, seleccionados al azar. Método: se administró el cuestionario Findrisk a los sujetos incluidos en el estudio por los alumnos en prácticas tuteladas de la Facultad de Farmacia de la Universidad de Santiago. Se clasificaron en función del riesgo bajo, ligero, moderado, alto y muy alto, y se realizó a todos ellos una intervención educativa. A los que tuvieron ≥12 puntos se les recomendó la visita al médico. RESULTADOS Y DISCUSIÓN: Cumplimentaron correctamente el cuestionario 381 sujetos. Hombres 142 (37,3%), mujeres 239 (62,7%). La media de puntuación del test findrisk fue menor en mujeres (7,8 ± 4,6) que en hombres (8,7 ± 4,5), pero la diferencia no fue estadísticamente significativa (t de Student= 1,7355, p= 0,0835). Se encontró también mayor porcentaje de hombres con riesgo medio a alto (27,5% vs 23,0%). CONCLUSIÓN: Se han encontrado cifras de riesgo de desarrollar diabetes a diez años superiores a las halladas en otros ámbitos. La aplicación del cuestionario findrisk no plantea problemas en su administración a los usuarios en la farmacia comunitaria. Todo ello la avala como un centro sanitario idóneo para realizar cribado de pacientes con diabetes no diagnosticada obteniendo un alto grado de eficiencia

Representaciones e imágenes de la diversidad cultural: Reflexiones a partir de un estudio exploratorio con profesores de escuelas multiculturales del suroeste de Andalucía

En este artículo se exponen las conclusiones de un estudio preliminar de carácter exploratorio realizado en escuelas multiculturales de la provincia de Huelva (Suroeste de España). Tras el establecimiento de un marco conceptual y la descripción analítica de la evolución del fenómeno de la inmigración en sus cifras fundamentales, se presentan los resultados de un estudio de campo, basado en entrevistas al profesorado y a otros actores escolares relevantes, de las que se extraen diferentes imágenes y estereotipos sobre el desarrollo educativo de niños y niñas inmigrantes. Por último, se sugieren algunas líneas de profundización en futuros estudios

Leveraging Experiential Learning to Foster University Students’ Proficiency in Engaging with People with Disabilities

Study purpose. Inclusive education, acknowledged as a fundamental human right, is aimed at enhancing the participation of all students and mitigating social and educational exclusion. Physical Education is identified as a vital instrument that fosters specific training on disability and inclusion, thereby ameliorating attitudes towards disability. The objective of this study is to scrutinize the perception of experiential learning and inclusive physical activity among students. Materials and methods. An inclusive physical activity program for students pursuing a degree in Early Childhood and Primary Education was designed. The program proposes five sessions of inclusive physical activity and accommodates 30 adult users with intellectual disability. To analyse the reliability and validity of a scale that measures students’ perception of experiential learning, descriptive statistics, reliability analysis, exploratory and confirmatory factor analysis were used to assess the effectiveness and inclusivity of the scale. Results. The validity and reliability of a scale that facilitates the analysis of students’ perceptions of learning derived from inclusive experiences is presented and the results are adequate for its usability. In addition, it is shown that experiential learning increases the perception towards the acquisition of disability-related competences among university students. Conclusions. This scale essentially allows a comprehensive analysis of students’ perception of learning that emerges from inclusive experiences. It is demonstrated that experiential learning enhances students’ perception regarding the attainment of competencies related to disability. These findings underscore the importance of inclusive learning experiences in the training of future educators