The H=xp model revisited and the Riemann zeros

Berry and Keating conjectured that the classical Hamiltonian H = xp is related to the Riemann zeros. A regularization of this model yields semiclassical energies that behave, in average, as the non trivial zeros of the Riemann zeta function. However, the classical trajectories are not closed, rendering the model incomplete. In this paper, we show that the Hamiltonian H = x (p + l_p^2/p) contains closed periodic orbits, and that its spectrum coincides with the average Riemann zeros. This result is generalized to Dirichlet L-functions using different self-adjoint extensions of H. We discuss the relation of our work to Polya's fake zeta function and suggest an experimental realization in terms of the Landau model.Comment: 5 pages, 3 figure

Effect of acid treatment on the structure of sepiolite.

An ab initio determination of the structure of sepiolite after acid treatment (HCl 0.5 N for 24 h) was carried out using X-ray powder diffraction data. After acid treatment, the sections normal to the a and c axes presented discontinuities, ~2.25 Å wide, parallel to the (010) plane, with no electronic density maxima, thus suggesting that adjacent planes are joined by van der Waals-like residual links. Partial dissolution was detected on both octahedral and tetrahedral sheets, beginning by breaking the ribbons not along the edges, but in the centre, thus creating a 5.20x6.79 Å tunnel along the a axis. By interrupting the tetrahedral sheet, this mechanism changes the phyllosilicate-like nature of the sepiolite to an inosilicate-like structure.Peer reviewe

Assessment of discretely measured indicators and maximum daily trunk shrinkage for detecting water stress in pomegranate trees

Measurements obtained by the continuous monitoring of trunk diameter fluctuations were comparedwith discrete measurements of midday stem water potential and midday leaf conductance (gl)in adult pomegranate trees (Punica granatum L. cv. Mollar de Elche). Control plants (T0) were irrigateddaily above their crop water requirements in order to attain non-limiting soil water conditions in 2009 and 2010, while T1 plants were subjected to water stress by depriving them of irrigation water for34 days in 2010, after which time irrigation was restored and plant recovery was studied for 7 days.T1 plants showed a substantial degree of water stress, which developed slowly. Maximum daily trunkshrinkage (MDS) was identified to be the most suitable plant-based indicator for irrigation scheduling inadult pomegranate trees, because its signal:noise ((T1/T0):coefficient of variation) ratio was higher thanthat for midday stem water potential((T1/T0):coefficient of variation) and gl((T0/T1):coefficient of variation). MDS increasedin response to water stress, but when the stemfell below ¿1.67 MPa, the MDS values decreased. Fornon-limiting water conditions, MDS could be predicted from mean daily air temperature (Tm) throughexponential equations fitted to pooled data across several seasons. First-order equations were alsoobtained by pooling data across several seasons to predict MDS from crop reference evapotranspira-tion (ETo), mean daily air vapour pressure deficit (VPDm), Tmand solar radiation (Rs), but these should beused only within a certain range of values (ETo, 2.1¿7.4 mm; VPDm, 0.64¿2.96 kPa; Tm, 12.1¿28.3¿C; Rs,119.4¿331.3 Wm¿2). Hence, automated MDS measurements have the potential to be used in irrigationscheduling of pomegranate, and these values can be normalized to non-limiting water conditions bylocally derived empirical relationships with meteorological variables.Ministerio de Ciencia e Innovación (CICYT/FEDER) AGL2010-19201-C04-01AGRAgencia Española de Cooperación Internacional para el Desarrollo (AECID

Assessment of discretely measured indicators and maximum daily trunk shrinkage for detecting water stress in pomegranate trees

8 páginas.-- 7 figuras.-- 3 tablas.-- 50 referenciasMeasurements obtained by the continuous monitoring of trunk diameter fluctuations were comparedwith discrete measurements of midday stem water potential and midday leaf conductance (gl)in adult pomegranate trees (Punica granatum L. cv. Mollar de Elche). Control plants (T0) were irrigateddaily above their crop water requirements in order to attain non-limiting soil water conditions in 2009 and 2010, while T1 plants were subjected to water stress by depriving them of irrigation water for34 days in 2010, after which time irrigation was restored and plant recovery was studied for 7 days.T1 plants showed a substantial degree of water stress, which developed slowly. Maximum daily trunkshrinkage (MDS) was identified to be the most suitable plant-based indicator for irrigation scheduling inadult pomegranate trees, because its signal:noise ((T1/T0):coefficient of variation) ratio was higher thanthat for midday stem water potential((T1/T0):coefficient of variation) and gl((T0/T1):coefficient of variation). MDS increasedin response to water stress, but when the stemfell below ¿1.67 MPa, the MDS values decreased. Fornon-limiting water conditions, MDS could be predicted from mean daily air temperature (Tm) throughexponential equations fitted to pooled data across several seasons. First-order equations were alsoobtained by pooling data across several seasons to predict MDS from crop reference evapotranspira-tion (ETo), mean daily air vapour pressure deficit (VPDm), Tmand solar radiation (Rs), but these should beused only within a certain range of values (ETo, 2.1¿7.4 mm; VPDm, 0.64¿2.96 kPa; Tm, 12.1¿28.3¿C; Rs,119.4¿331.3 Wm¿2). Hence, automated MDS measurements have the potential to be used in irrigationscheduling of pomegranate, and these values can be normalized to non-limiting water conditions bylocally derived empirical relationships with meteorological variables.This research was supported by Ministerio de Ciencia e Innovación (MICINN) (CICYT/FEDER AGL2010-19201-C04-01AGR) and Agencia Española de Cooperación Internacional para el Desarrollo (AECID) (A1/035430/11) grants to the authors

Principales fallas activas de las Cuencas de Granada y Guadix-Baza (Cordillera Bética)

The Granada and Guadix-Baza Basins, the largest Neogene-Quaternary intramontane basins of the Betic Cordillera (southern Spain), undergo active deformation with an associated moderate level of seismic activity. This deformation is controlled by a NNWSSE compressive regime and an approximate orthogonal tensional regime. The compression produced N70ºE to E-W folds of several scales, the Sierra Nevada antiform being the largest one. The tension is accommodated mainly by NW-SE active normal faults, the most notable being the Baza Fault, in the Guadix-Baza Basin, and the Granada, Sierra Elvira-Dílar and Padul-Dúrcal Faults, in the Granada Basin. In addition, other active faults with different orientations also exist, such as the Alfahuara-Botardo and the Galera faults in the Guadix-Baza Basin, and the Huenes, Obéilar-Pinos Puente and N of Sierra Tejeda Faults in the Granada Basin. Moreover, in several sectors, the presence of orthogonal normal fault sets suggests alternating trends or even radial extension. Slip rates of these active faults, based on geologic markers, vary between 0.06 and 0.5 mm/year. Estimates for the maximum expected magnitude of earthquakes caused by these faults vary between MW 6.0 and 7.0. The N of Sierra Tejeda and the Baza Faults, the largest faults in the Granada and Guadix-Baza Basins, respectively, have the greatest seismic potential. They could cause events up to a magnitude of MW 6.5-7.0, although their reference earthquakes, computed for a return period of 475 years, are on the order of MW 5.0-5.5.Las Cuencas de Granada y Guadix-Baza, las mayores cuencas intramontañosas del Neógeno y Cuaternario de la Cordillera Bética (sur de España), experimentan una deformación activa y tienen asociada una actividad sísmica moderada. La deformación está controlada por una compresión NNO-SSE y una tensión aproximadamente perpendicular. La compresión ha formado pliegues de dirección N70ºE a E-O de muy diferentes tamaños, siendo el antiforme de Sierra Nevada el mayor. La tensión se acomoda sobre todo por fallas normales NO-SE, siendo las más notables de ellas la falla de Baza, en la cuenca de Guadix-Baza, y las de Granada, Sierra Elvira-Dílar y Padul-Dúrcal, en la cuenca de Granada. Además, existen otras fallas activas con diferentes orientaciones, tales como la de Alfahuara-Botardo y la de Galera en la cuenca de Guadix-Baza y las de Huenes, Obéilar-Pinos Puente y norte de Sierra Tejeda en la cuenca de Granada. Además, en varios sectores, la presencia de juegos de fallas ortogonales sugiere cambios en el elipsoide de esfuerzos e incluso una extensión radial. Las tasas de desplazamiento de estas fallas activas, calculadas a partir de marcadores geológicos, varían entre 0,06 y 0,5 mm/año. La estimación del potencial sísmico indica que la máxima magnitud esperable de los terremotos producidos por estas fallas varía entre MW 6,0 y 7,0. La falla del N de Sierra Tejeda y la de Baza, las mayores respectivamente en las Cuencas de Granada y Guadix-Baza, tienen el mayor potencial sísmico. Podrían causar eventos con magnitudes del orden de MW 6,5-7,0, aunque sus terremotos de referencia para un periodo de retorno de 475 años son del orden de MW 5,0-5,5

Indigencia, un abordaje multidisciplinar y una propuesta de intervención en la Zona Centro de Guadalajara

El trabajo se propone hacer un abordaje multidisciplinario de tipo exploratorio en el que se estudien aspectos legales, económicos, sociales, asistenciales, culturales y de difusión del fenómeno de la indigencia y de los actores que la viven y conviven con ella pensando en que este tema podría dar pie a abordajes más profundos desde la academia y otras instancias

Conventional Chemotherapy Followed By Consolidation With Autologous Hematopoietic Transplantation vs Chemotherapy Alone In HIV+ Patients With Large B Cell Lymphoma (LBCL) In First Complete Remission (CR). A Retrospective Analysis On Behalf Of The EBMT Lymphoma Working Party And The GESIDA/PETHEMA Registry Of HIV+ Patients With Non-Hodgkin's Lymphoma (NHL)

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Alien Health: Promoting nutrition with video games in support of a science education curriculum in Chile

In order to be successful on a complex, computer-based and knowledge-driven society, both students and teachers must include Information and Communication Technologies (ICT) efficiently in learning and instruction. The visual nature of some technologies, particularly animations, simulations and mobile imagery, engages more students and reinforces the understanding of content. Video games offer the possibility to understand complex real-world ideas in an interactive manner both within the classroom as well as outside of it. An educational intervention was carried out through the collaboration between Chile, United States and Spain, focusing on the use of an interactive videogame to strengthen healthy nutrition habits with 45 primary education students in Chile. All students participated in a regular natural sciences unit during three weeks. Afterwards, the 3th graders were randomly assigned to either the ‘‘Alien Health’’ videogame or a treated control condition. A pre and post-intervention food habits test measured the acquisition of the knowledge content. Statistical analysis showed that the experimental group obtained significant learning gains on both the immediate nutrition knowledge and in the follow up test, compared to the control group. There were no gender differences. We can conclude a positive effect in knowledge retention, which suggests that the game and its narrative may have instructed in and helped to consolidate content memory