Improvement of scanning tunneling microscopy resolution with H-sensitized tips

Recent scanning tunneling hydrogen microscopy (STHM) experiments on PTCDA (perylene-3,4,9,10- tetracarboxylic-3,4,9,10-dianhydride)/Au(111) have shown unprecedented intramolecular and intermolecular spatial resolution. The origin of this resolution is studied using an accurate STHM theoretical simulation technique that includes a detailed description of the electronic structure of both the tip and sample. Our results show that H2 molecules are dissociated on the Au tip; the adsorbed H atoms change the density of states at the Fermi level (EF) of the tip, increasing its p-orbital character and reducing the s-orbital contribution. Also, due to the interaction with the H-decorated tip, EF is shifted to the middle of the PTCDA lowest unoccupied molecular orbital peak, increasing dramatically the density of states of the sample at EF. These effects give rise to the enhanced STHM resolutionThis work is supported by Spanish MICIIN under Contract No. FIS2010-16046, the CAM under Contract No. S2009/MAT-1467, and the European Project MINOTOR (Grant No. FP7-NMP-228424). J. I. M. acknowledges funding from Spanish MICINN through Juan de la Cierva Program, E. A. the financial support by Consejería de Educación de la CAM, FSE, and European Project MINOTOR, and C. G. the CSIC JA

Textural and geochemical features of pyrite from the intramagmatic Ni-Cu-PGE mineralization of Aguablanca (Badajoz)

Depto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasFALSEEspaña. Dirección General de Investigación Científica y Técnicapu

Towards an increase of flash flood geomorphic effects due to gravel mining and ground subsidence in Nogalte stream (Murcia, SE Spain)

Transition from endorheic alluvial fan environments to well-channelized fluvial systems in natural conditions may occur in response to base-level fluctuations. However, human-induced changes in semi-arid regions can also be responsible for similar unforeseen modifications. Our results confirm that in-channel gravel mining and aquifer overexploitation over the last 50 years in the case study area have changed the natural stability of the Nogalte stream and, as a result, its geomorphic parameters including channel depth and longitudinal profile have begun to adapt to the new situation. Using interferometric synthetic aperture radar (InSAR) data we obtain maximum values for ground subsidence in the Upper Guadalentín Basin of  ∼ 10 cm yr−1 for the period 2003–2010. In this context of a lowered base level, the river is changing its natural flood model to a more powerful one. A comparison of the 1973 flood event, the most dramatic flood event ever recorded in the area, with the 2012 event, where there was a similar discharge but a sediment load deficit, reveals greater changes and a new flooding pattern and extension. In-channel gravel mining may be responsible for significant local changes in channel incision and profile. This, together with the collateral effects of aquifer overexploitation, can favour increased river velocity and stream power, which intensify the consequences of the flooding. The results obtained here clearly demonstrate an existing transition from the former alluvial pattern to a confined fluvial trend, which may become more pronounced in the future due to the time lag between the drop in aquifer level and ground subsidence, and introduce a new scenario to be taken into consideration in future natural hazard planning in this area.s. This research was partially funded by projects CGL 2011-23857, ESP2013-47780-C2-2-R and CGL2013-47412-C2-1-P (Spanish Ministry of Economy and Competitiveness).Peer reviewe

Vivienda obrera minera en Cartagena-La Unión

The mining “boom” experienced during the XIX century in Cartagena caused a great demographic increase. Population that needs new housing moves to there in a desperate search of new incomes. New villages rose such as “El Estrecho de San Gines” and “El Beal”, and the building of new houses in old zones such as La Unión was increased drastically. Negligible houses were built with similar characteristics, always constructed with poor materials due to lower incomes. Even in the case of the poorest miners, dwelling in caves very close to the mine, homes knowing as “casas-cueva”. Meanwhile a rich highborn people, the owners of the mines, built new and luxury houses, influenced by the modernist architecture wave that rules in Europe. A deep investigation through every plane in the municipal archive of La Unión made locate old planes possible, these planes together with searches over the remainders that nowadays are able to find confirms the main features of the houses built during the objective epoch

Diagnosis of a Chopper Controlled DC Motor by Boosting

This paper proposes a methodology to diagnose a transient state of a dynamic system using boosting. The methodology is composed by two steps: one off-line process and another on-line process. The off-line phase begins gathering data from the system, both when it is running free of fault and when the system is running in each fault mode. A segmentation and normalization algorithm is used to reduce the large amount of gathered data. The final step is the generation of a decision tree by a classification tool. The boosting technique is used with the aim of improving the classification results. The on-line process of the methodology consists of evaluating a new reading of the system sensors with the generated decision trees. The diagnosis of the system is the result of this evaluation which has very low computational cost due to the simplicity of the decision trees. Also, the implementation cost is very low due to this simplicity.Ministerio de Ciencia y Tecnología DPI2003-07146-C02-0

C6H6/Au(111): Interface dipoles, band alignment, charging energy, and van der Waals interaction

The following article appeared in Journal of Chemical Physics 134.4 (2011): 044701 and may be found at http://scitation.aip.org/content/aip/journal/jcp/134/4/10.1063/1.3521271.We analyze the benzene/Au(111) interface taking into account chargingenergy effects to properly describe the electronic structure of the interface and van der Waals interactions to obtain the adsorption energy and geometry. We also analyze the interface dipoles and discuss the barrier formation as a function of the metal work-function. We interpret our DFT calculations within the induced density of interface states (IDIS) model. Our results compare well with experimental and other theoretical results, showing that the dipole formation of these interfaces is due to the charge transfer between the metal and benzene, as described in the IDIS model.This work is supported by Spanish MICIIN under Contracts No. MAT2007-60966 and No. FIS2010-16046, the CAM under Contract No. S2009/MAT-1467, and the European Project MINOTOR (Grant No. FP7-NMP-228424). E.A. gratefully acknowledges financial support by the Consejería de Educación of the CAM and the FSE. J.I.M. acknowledges funding from Spanish MICINN through Juan de la Cierva Program

Soft nanostructures out of star-shaped triazines with flexible amide spacers: liquid crystals with a cubic to columnar transition with memory effect, gels and supramolecular chirality

This work reports the synthesis and characterization of a new family of star-shaped tricarboxamides with C3-symmetry that have flexible amide spacers linking a tris(triazolyl)triazine core with three trialkoxyphenyl groups. The presence of amide groups allows the formation of intermolecular hydrogen bonds that reinforce π-stacking and van der Waals interactions, promoting liquid crystalline behavior, and self-assembly in solvents leading to organogels. As determined by polarized optical microscopy, differential scanning calorimetry and X-ray diffraction on powder samples, all the three reported molecules present a hexagonal columnar (Colh) phase stable at room temperature. Interestingly, they show a transition to a cubic micellar mesophase (BCC) at high temperatures. A mechanism for this transition, which is consistent with the fragmentation of columns to form supramolecular spheres, was elucidated from X-ray studies on aligned samples. Moreover, on cooling from the BCC to the columnar phase a preferential orientation of columns occurs, according to which each cubic domain gives rise to four hexagonal domains. The ability of the synthesized structures to aggregate in solvent media was studied in a variety of organic solvents, and all of them were able to gel 1-octanol at low concentrations. X-ray studies of gels and xerogels were carried out and showed a molecular organization consistent with Colh order. FTIR studies were carried out to analyze the formation of hydrogen bonds and the influence of the length of the flexible spacer in the liquid crystalline state and in the organogels. Furthermore, the presence of a stereogenic center in the flexible amide spacer leads to macroscopic chirality in the liquid crystal state and the organogels in 1-octanol as demonstrated by circular dichroism spectroscopy

Filter optimization and complexity reduction for video coding using graph-based transforms

The basis functions of lifting transform on graphs are completely determined by finding a bipartition of the graph and defining the prediction and update filters to be used. In this work we consider the design of prediction filters that minimize the quadratic prediction error and therefore the energy of the detail coefficients, which will give rise to higher energy compaction. Then, to determine the graph bipartition, we propose a distributed maximum-cut algorithm that significantly reduces the computational cost with respect to the centralized version used in our previous work. The proposed techniques show improvements in coding performance and computational cost as compared to our previous work.This work was supported in part by NSF under grant CCF-1018977Publicad

Aggressive and bullying from the perspective of, physical activity, place of residence and sex behavior among adolescents in Granada

En este trabajo de investigación se tiene como objetivo analizar y establecer los índices de Victimización, Bullying y Conducta Violenta y su posible relación con el género, residencia habitual y práctica de A.F de adolescentes de 13 a 17 años de Granada (España). La participación de un total de 2.273 adolescentes permitió el registro y evaluación de las variables Victimización (escala de Victimización en la Escuela), Conducta Violenta (medida con la escala de Conducta Violenta en la Escuela), Bullying, género, lugar de residencia y práctica de Actividad Física. Los resultados mostraron que los adolescentes en más de la mitad de los casos indicaron que sin ser agresores sí que fueron testigos de casos de Bullying, también se detectó que los niveles de Agresividad (Manifiesta y Relacional) eran similares, mientras que la Victimización de tipo Verbal era la más usual. Asimismo los jóvenes residentes fuera del contexto familiar eran más acosadores y habían sufrido más acoso y tenían mayores índices de agresividad y victimización. La práctica de Actividad Física era más asidua en varones, y estos se caracterizaban por tener mayor agresividad manifiesta y un índice superior de victimización física, encontrándose más acosadores entre los varones y siendo estos más testigos de hechos violentos, mientras las chicas lo sufrían más y a la vez percibían menos situaciones de Bullying. Como principal recomendación indicamos la necesidad de estudiar con mayor profundidad a la población deportivamente activa para intentar dilucidar la casuística de estos resultados.In this research the aim was to analyze and establish the rates of victimization, bullying and violent conduct and its possible relationship to gender, habitual residence and Physical Activity Practice among teens from13-17 years of Granada (Spain). The participation of a total of 2, 273 adolescents allowed the registration and evaluation of Victimization (Scale  Victimization at School), Violent Conduct (measured with the scale of violent conduct at the School), Bullying, Gender, Place of residence and  Physical Activity practice variables. The results showed that adolescents in over half of the cases indicated that without being perpetrators themselves had witnessed cases of bullying, also found that levels of aggressiveness (Manifest and Relational) were similar, while the verbal victimization was more usual. It was also found that young teenagers residing outside the family context were bullies and had suffered further harassment and had higher rates of aggressiveness and victimization. The practice of physical activity was more frequent in males, and these were characterized by greater manifestation of aggressiveness and a higher rate of physical victimization, existing more stalkers among men and still more witnesses to these violent events, while the girls suffered more and perceived less bullying situations. It could be indicated as a main recommendation the need to further explore the physically active population to try to elucidate the casuistry of these results