Ultra wideband: applications, technology and future perspectives

Ultra Wide Band (UWB) wireless communications offers a radically different approach to wireless communication compared to conventional narrow band systems. Global interest in the technology is huge. This paper reports on the state of the art of UWB wireless technology and highlights key application areas, technological challenges, higher layer protocol issues, spectrum operating zones and future drivers. The majority of the discussion focuses on the state of the art of UWB technology as it is today and in the near future

The Unique Ambiphilicity of Tellurium in the [MesitylTe(I)(I2)(I3)]− Anion

A first example of an aryltellurium(II) compound with three different bonding modes to iodine featuring covalent and non-covalent bonds such as two orthogonal, ambiphilic σ-hole interactions is introduced: [MesTe(I)(I2)(I3)]−. It is a member of a series of mesityltellurenyl anions, which are formed during reactions of (MesTe)2 with ZnI2, phenanthroline (phen) and iodine. [Zn(phen)3][MesTe(I)2] (1), [Zn(phen)3][{MesTe(I)-(I)…Te(I)Mes}{MesTeI2}] (2) and [Zn(phen)3][MesTe(I)(I2)(I3)][MesTeI2] (3) are isolated depending on the amount of iodine used. The products contain tellurium atoms bonded to a variety of iodine species (I−, μ2-I−, I2 and I3−) and are, thus, perfectly suitable to explore the amphiphilic behavior of tellurium(II) and its relevance for the formation of non-covalent bonds, where tellurium acts as both donor and acceptor simultaneously. The character of chalcogen and halogen bonds are evaluated by the combination of crystallographic data and computational methods

Дослідження багатошарових нейронних мереж для автоматичного виділення ознак при вирішенні задачі розпізнавання образів

В роботі розглянуто підходи до виділення ознак при розпізнаванні образів і застосування багатошарових нейронних мереж для розв'язання таких задач. Проведено процес моделювання багатошарового перцептрону для автоматичного виділення ознак зображення і подальшої класифікації. Досліджено вплив базових параметрів на якість розпізнавання.The paper deals with approaches to feature extraction in pattern recognition and application of multilayer neural nets for solving such problems. The modeling process of multilayer perceptron for automatic feature extraction and further classification is described. The basic parameters influence on quality of recognition is researched

Reliability of cross-regional applications of global fire danger models: a Peruvian case study

Background: Fire danger indexes (FDIs) are used as proxies for fire potential and are often developed for specific locations. For practical purposes, the extrapolation of the underlying calculations into novel locations is common, but it is generally uncertain if the relationships between FDIs and fire potential observed in the environment in which the index was developed are equally relevant in others. For example, although a topographically, ecologically, and climatologically complex country, f ire danger forecasts in Peru use a standard set of nationwide thresholds applied to the Fire Weather Index. In this study, we validate the underlying assumption that weather-fire relationships are spatially uniform within Peru by (1) making cross-regional comparisons of the statistical distributions of four FDIs—Burning Index, Energy Release Component, Fire Weather Index, and Keetch-Byram Drought Index, and (2) making cross-regional comparisons of the expected daily MODIS hotspot count percentiles conditioned on FDI values. Results: Significant regional differences in the distributions of daily FDI values were observed in every pair of regions within Peru, and with the exception of a pair of regions within the Amazon, little data (< 90 days) were necessary to detect these differences. After controlling for FDI values and seasonal and annual effects with regressions, differences in predicted hotspot percentiles were common, differing by as much as 47 percentage points. Across the pairs of regions, the magnitude of these differences tended to decrease as climatic similarity increased, but some counterexamples were also apparent. Conclusions: The noticeable differences in the distributions of daily FDI values suggest that a standard set of breakpoints may produce unreliable inferences regarding fire potential. We also find that even if the climatic conditions were similar across Peru, the same FDI values in two locations can produce substantially differing predictions of wildfire activity. This suggests that other factors besides FDI values can strongly mediate wildfire activity and that better fire potential predictions could be produced if these factors are accounted for

Eliminación y prevención de la deficiencia de yodo en mujeres gestantes de Perú

La deficiencia de yodo (DI) causa daño a través de todos los ciclos de la vida, la vulnerabilidad es mayor durante la gestación y la infancia. La yodación universal de la sal (IUS) para consumo humano es la estrategia más costo-efectiva y sostenible para su control. Perú ha logrado la eliminación sostenida de los desórdenes por deficiencia de yodo (DDI) desde 1994. Objetivo: Determinar la efectividad del programa nacional de control de los DDI y la estrategia IUS para satisfacer el mayor requerimiento de yodo y asegurar la nutrición óptima de yodo de las mujeres embarazadas de la sierra, una región con severa deficiencia natural de yodo. Material y Métodos: El estudio ha incluido a 489 mujeres embarazadas de la sierra, seleccionadas entre las asistentes a control pre natal en los centros asistenciales. En cada sujeto se verificó el consumo de sal yodada y se colectó una muestra casual de orina para el análisis de la concentración de yodo y creatinina. Resultados: Según la encuesta de admisión el 99.6 % de los hogares consumen sal yodada. La mediana global de la concentración urinaria de yodo (CUI) 209 μg/L está dentro del rango adecuado para gestantes y demuestra un estado nutricional de yodo normal. La concentración de creatinina en la orina es normal. Conclusión: Estos resultados confirman la eficiencia y el éxito del programa nacional para la eliminación sostenida de los DDI, garantizando la nutrición normal de yodo durante la gestación y, por lo tanto, previniendo el riesgo de daño cerebral de los recién nacidos cada año en la sierra

Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

A measurement of the cosmic-ray spectrum for energies exceeding $4{\times}10^{18}$ eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\circ}$ detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above $5.3{\times}10^{18}$ eV, the "ankle", the flux can be described by a power law $E^{-\gamma}$ with index $\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)}$ followed by a smooth suppression region. For the energy ($E_\text{s}$) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find $E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19}$ eV.Comment: Replaced with published version. Added journal reference and DO

Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO

Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principle calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI. Supplemental material in the ancillary file

Azimuthal anisotropy of charged jet production in root s(NN)=2.76 TeV Pb-Pb collisions

We present measurements of the azimuthal dependence of charged jet production in central and semi-central root s(NN) = 2.76 TeV Pb-Pb collisions with respect to the second harmonic event plane, quantified as nu(ch)(2) (jet). Jet finding is performed employing the anti-k(T) algorithm with a resolution parameter R = 0.2 using charged tracks from the ALICE tracking system. The contribution of the azimuthal anisotropy of the underlying event is taken into account event-by-event. The remaining (statistical) region-to-region fluctuations are removed on an ensemble basis by unfolding the jet spectra for different event plane orientations independently. Significant non-zero nu(ch)(2) (jet) is observed in semi-central collisions (30-50% centrality) for 20 <p(T)(ch) (jet) <90 GeV/c. The azimuthal dependence of the charged jet production is similar to the dependence observed for jets comprising both charged and neutral fragments, and compatible with measurements of the nu(2) of single charged particles at high p(T). Good agreement between the data and predictions from JEWEL, an event generator simulating parton shower evolution in the presence of a dense QCD medium, is found in semi-central collisions. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Peer reviewe