Estimación de variables dasométricas a partir de datos LiDAR PNOA en masas regulares de Pinus halepensis Mill.

El conocimiento de las masas forestales es fundamental para su correcta gestión y ordenación. En ocasiones no basta con un inventario cualitativo del monte, siendo necesaria una valoración cuantitativa, mediante la estimación de variables dasométricas. La tecnología LiDAR aporta una nueva perspectiva a los inventarios forestales al ofrecer de forma directa información tridimensional de toda la superficie. El IGN inició en 2008-2009 la captura de datos LiDAR para gran parte de España, dentro del Plan Nacional de Ortofotografía Área (PNOA). Este trabajo pretende evaluar la adecuación de estos datos para estimar variables dasométricas en masas regulares de Pinus halepensis Mill. El área de estudio son los montes “Dehesa de los Enebrales” y “Valdá y Carrilanga” (Daroca, Zaragoza). Se han generado modelos de regresión lineal múltiple entre las variables dasométricas, obtenidas en 61 parcelas de campo, y una colección de variables estadísticas extraídas de la nube de puntos LiDAR. Los coeficientes de determinación corregidos obtenidos son 0,867 para la estimación del volumen, 0,854 para el área basimétrica, 0,858 para la densidad y 0,799 para la altura media. Las variables LiDAR introducidas en los modelos en general incluyen al menos un estadístico referente a altura (m) y otro a la distribución horizontal de la nube de puntos

The G_2 sphere over a 4-manifold

We present a construction of a canonical G_2 structure on the unit sphere tangent bundle S_M of any given orientable Riemannian 4-manifold M. Such structure is never geometric or 1-flat, but seems full of other possibilities. We start by the study of the most basic properties of our construction. The structure is co-calibrated if, and only if, M is an Einstein manifold. The fibres are always associative. In fact, the associated 3-form results from a linear combination of three other volume 3-forms, one of which is the volume of the fibres. We also give new examples of co-calibrated structures on well known spaces. We hope this contributes both to the knowledge of special geometries and to the study of 4-manifolds.Comment: 13 page

Comparative study of the structural and optical properties of epitaxial CuFeO2 and CuFe1 - xGaxO2 delafossite thin films grown by pulsed laser deposition methods

Three samples of epitaxial delafossite CuFeO2 and CuFe1 − xGaxO2 films were grown using Pulsed Laser Deposition techniques in high vacuum. The sample thicknesses were estimated to be 21 nm, 75 nm for the CuFeO2 films and ~ 37 nm for the composite sample containing gallium. The estimated gallium fraction of substituted ferric atoms was x = 0.25 for the composite sample. We present the study of the fundamental band gap(s) for each sample via observation of their respective optical absorption properties in the NIR-VIS region using transmittance and diffuse reflection spectroscopy. Predominant absorption edges measured at 1.1 eV and 2.1 eV from transmittance spectra were observed for the CuFeO2 samples. The sample of CuFe1 − xGaxO2 showed a measurable shift to 1.5 eV of the lower band-gap and a strong absorption edge located at 2.3 eV attributed to direct band to band transitions. This study also found evidence of changes between apparent absorption edges between transmittance and diffuse reflectance spectroscopies of each sample and it may be resultant from absorption channels via surface states

Efficacy of antiemetic therapy in patients undergoing laparoscopic cholecystectomy

AbstractIntroductionA high incidence of postoperative nausea and vomiting has been observed in patients undergoing laparoscopic cholecystectomy (20–40%). This causes an increase in patient discomfort, a delay in recovery, and an increase in hospital stay.ObjectiveCompare the efficacy of ondansetron plus metoclopramide and ondansetron alone in the control of postoperative nausea and vomiting in patients undergoing laparoscopic cholecystectomy.Material and methodsA comparative, prospective, experimental, longitudinal double blind study was performed with 30 patients programmed for laparoscopic cholecystectomy. The Apfel score was applied postoperatively. Patients were divided into two groups with 15 participants. Metoclopramide 10mg and ondansetron 4mg were administered in the first Group (A), and ondansetron 4mg in the second Group (B), after induction of anesthesia. Nausea and vomiting were evaluated for 24h postoperatively using a Likert scale.ResultsOf the patients who presented nausea, the condition was mild. The patient who presented vomiting, vomited only once. Neither group required rescue drugs. Regarding the Apfel score, there was no correlation between the percentage of stratified risk and the patients who presented postoperative nausea and vomiting.ConclusionsNo statistically significant difference was observed between ondansetron plus metoclopramide and ondansetron alone in patients subjected to laparoscopic cholecystectomy

Tight-binding parameters for charge transfer along DNA

We systematically examine all the tight-binding parameters pertinent to charge transfer along DNA. The $\pi$ molecular structure of the four DNA bases (adenine, thymine, cytosine, and guanine) is investigated by using the linear combination of atomic orbitals method with a recently introduced parametrization. The HOMO and LUMO wavefunctions and energies of DNA bases are discussed and then used for calculating the corresponding wavefunctions of the two B-DNA base-pairs (adenine-thymine and guanine-cytosine). The obtained HOMO and LUMO energies of the bases are in good agreement with available experimental values. Our results are then used for estimating the complete set of charge transfer parameters between neighboring bases and also between successive base-pairs, considering all possible combinations between them, for both electrons and holes. The calculated microscopic quantities can be used in mesoscopic theoretical models of electron or hole transfer along the DNA double helix, as they provide the necessary parameters for a tight-binding phenomenological description based on the $\pi$ molecular overlap. We find that usually the hopping parameters for holes are higher in magnitude compared to the ones for electrons, which probably indicates that hole transport along DNA is more favorable than electron transport. Our findings are also compared with existing calculations from first principles.Comment: 15 pages, 3 figures, 7 table

Search for charginos in e+e- interactions at sqrt(s) = 189 GeV

An update of the searches for charginos and gravitinos is presented, based on a data sample corresponding to the 158 pb^{-1} recorded by the DELPHI detector in 1998, at a centre-of-mass energy of 189 GeV. No evidence for a signal was found. The lower mass limits are 4-5 GeV/c^2 higher than those obtained at a centre-of-mass energy of 183 GeV. The (\mu,M_2) MSSM domain excluded by combining the chargino searches with neutralino searches at the Z resonance implies a limit on the mass of the lightest neutralino which, for a heavy sneutrino, is constrained to be above 31.0 GeV/c^2 for tan(beta) \geq 1.Comment: 22 pages, 8 figure

Heavy quarkonium: progress, puzzles, and opportunities

A golden age for heavy quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the $B$-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing investigations. The plethora of newly-found quarkonium-like states unleashed a flood of theoretical investigations into new forms of matter such as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the spectroscopy, decays, production, and in-medium behavior of c\bar{c}, b\bar{b}, and b\bar{c} bound states have been shown to validate some theoretical approaches to QCD and highlight lack of quantitative success for others. The intriguing details of quarkonium suppression in heavy-ion collisions that have emerged from RHIC have elevated the importance of separating hot- and cold-nuclear-matter effects in quark-gluon plasma studies. This review systematically addresses all these matters and concludes by prioritizing directions for ongoing and future efforts.Comment: 182 pages, 112 figures. Editors: N. Brambilla, S. Eidelman, B. K. Heltsley, R. Vogt. Section Coordinators: G. T. Bodwin, E. Eichten, A. D. Frawley, A. B. Meyer, R. E. Mitchell, V. Papadimitriou, P. Petreczky, A. A. Petrov, P. Robbe, A. Vair

Hadronization properties of b quarks compared to light quarks in e+e- -> q qbar from 183 to 200 GeV

The DELPHI detector at LEP has collected 54 pb^{-1} of data at a centre-of-mass energy around 183 GeV during 1997, 158 pb^{-1} around 189 GeV during 1998, and 187 pb^{-1} between 192 and 200 GeV during 1999. These data were used to measure the average charged particle multiplicity in e+e- -> b bbar events, _{bb}, and the difference delta_{bl} between _{bb} and the multiplicity, _{ll}, in generic light quark (u,d,s) events: delta_{bl}(183 GeV) = 4.55 +/- 1.31 (stat) +/- 0.73 (syst) delta_{bl}(189 GeV) = 4.43 +/- 0.85 (stat) +/- 0.61 (syst) delta_{bl}(200 GeV) = 3.39 +/- 0.89 (stat) +/- 1.01 (syst). This result is consistent with QCD predictions, while it is inconsistent with calculations assuming that the multiplicity accompanying the decay of a heavy quark is independent of the mass of the quark itself.Comment: 13 pages, 2 figure

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results