Applications of TIMS data in agricultural areas and related atmospheric considerations

While much of traditional remote sensing in agricultural research was limited to the visible and reflective infrared, advances in thermal infrared remote sensing technology are adding a dimension to digital image analysis of agricultural areas. The Thermal Infrared Multispectral Scanner (TIMS) an airborne sensor having six bands over the nominal 8.2 to 12.2 m range, offers the ability to calculate land surface emissivities unlike most previous singular broadband sensors. Preliminary findings on the utility of the TIMS for several agricultural applications and related atmospheric considerations are discussed

Combined photo- and electroreflectance of multijunction solar cells enabled by subcell electric coupling

Electric coupling between subcells of a monolithically grown multijunction solar cell in short circuit allows their simultaneous and independent characterization by means of photo- and electroreflectance. The photovoltage generated by selective absorption of the pump beam in a given subcell during photoreflectance measurements results in reverse biasing the complementary subunits at the modulation frequency set on the pump illumination. Such voltage bias modulation acts then as external perturbation on the complementary subcells. The spectral separation of the different subcell absorption ranges permits the probe beam to record in a single spectrum the response of the complete device as a combination of photo- and electroreflectance, thereby providing access for diagnosis of subcells on an individual basis. This form of modulation spectroscopy is demonstrated on a GaInP/GaAs tandem solar cell.Comment: 5 pages, 4 figures. This article has been accepted by Appl. Phys. Lett. After it is published, it will be found at https://doi.org/10.1063/1.506260

Searching for Very High Energy Emission from Pulsars Using the High Altitude Water Cherenkov (HAWC) Observatory

There are currently over 160 known gamma-ray pulsars. While most of them are detected only from space, at least two are now seen also from the ground. MAGIC and VERITAS have measured the gamma ray pulsed emission of the Crab pulsar up to hundreds of GeV and more recently MAGIC has reported emission at $\sim2$ TeV. Furthermore, in the Southern Hemisphere, H.E.S.S. has detected the Vela pulsar above 30 GeV. In addition, non-pulsed TeV emission coincident with pulsars has been detected by many groups, including the Milagro Collaboration. These GeV-TeV observations open the possibility of searching for very-high-energy (VHE, > 100GeV) pulsations from gamma-rays pulsars in the HAWC field of view.Comment: Presented at the 34th International Cosmic Ray Conference (ICRC2015), The Hague, The Netherlands. See arXiv:1508.03327 for all HAWC contribution

Additional Dimensions to the Study of Funnels in Combinatorial Landscapes

The global structure of travelling salesman's fitness landscapes has recently revealed the presence of multiple `funnels'. This implies that local optima are organised into several clusters, so that a particular local optimum largely belongs to a particular funnel. Such a global structure can increase search difficulty, especially, when the global optimum is located in a deep, narrow funnel. Our study brings more precision (and dimensions) to the notion of funnels with a data-driven approach using Local Optima Networks and the Chained Lin-Kernighan heuristic. We start by exploring the funnel 'floors', characterising them using the notion of communities from complex networks. We then analyse the more complex funnel 'basins'. Since their depth is relevant to search, we visualise them in 3D. Our study, across a set of TSP instances, reveals a multi-funnel structure in most of them. However, the specific topology varies across instances and relates to search difficulty. Finally, including a stronger perturbation into Chained Lin-Kernighan proved to smooth the funnel structure, reducing the number of funnels and enlarging the valley leading to global optima

Electron spin relaxation in graphene with random Rashba field: Comparison of D'yakonov-Perel' and Elliott-Yafet--like mechanisms

Aiming to understand the main spin relaxation mechanism in graphene, we investigate the spin relaxation with random Rashba field induced by both adatoms and substrate, by means of the kinetic spin Bloch equation approach. The charged adatoms on one hand enhance the Rashba spin-orbit coupling locally and on the other hand serve as Coulomb potential scatterers. Both effects contribute to spin relaxation limited by the D'yakonov-Perel' mechanism. In addition, the random Rashba field also causes spin relaxation by spin-flip scattering, manifesting itself as an Elliott-Yafet--like mechanism. Both mechanisms are sensitive to the correlation length of the random Rashba field, which may be affected by the environmental parameters such as electron density and temperature. By fitting and comparing the experiments from the Groningen group [J\'ozsa {\it et al.}, Phys. Rev. B {\bf 80}, 241403(R) (2009)] and Riverside group [Pi {\it et al.}, Phys. Rev. Lett. {\bf 104}, 187201 (2010); Han and Kawakami, {\it ibid.} {\bf 107}, 047207 (2011)] which show either D'yakonov-Perel'-- (with the spin relaxation rate being inversely proportional to the momentum scattering rate) or Elliott-Yafet--like (with the spin relaxation rate being proportional to the momentum scattering rate) properties, we suggest that the D'yakonov-Perel' mechanism dominates the spin relaxation in graphene. The latest experimental finding of a nonmonotonic dependence of spin relaxation time on diffusion coefficient by Jo {\it et al.} [Phys. Rev. B {\bf 84}, 075453 (2011)] is also well reproduced by our model.Comment: 13 pages, 9 figures, to be published in New J. Phy

Recovery of Total Chromium from Tannery Wastewater by Carbonization Application

A carbonization process was carried out for the recovery of chromium from wastewater by chemical treatment with sodium hydroxide as a basic solution in contact with the precursor material at different concentrations [1:0.15 (%w/w) - 1:0.20 (%w/w)]. The physical treatment was carried out with carbonization at 700∘C for a period of 2 hours. The obtained samples were characterized by elemental analysis, thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), atomic absorption spectroscopy, and surface area analysis (BET) to validate the evidence of metal recovery. The results indicate that the percentage of total chromium recovery was 47.62% with respect to the uncarbonized material, establishing that the best carbonization variables are at 700∘C and concentration 1:0.20% w/w for 2 hours. Keywords: tannery industry, carbonization, recovery, total chromium. Resumen Se realizó un proceso de carbonización para la recuperación de cromo a partir de aguas residuales mediante un tratamiento químico con hidróxido de sodio como solución básica en contacto con el material precursor a diferentes concentraciones [1:0,15 (%p/p)- 1:0,20 (%p/p)], el tratamiento físico se realizó con la carbonización a 700∘C por un lapso de 2 horas. Las muestras obtenidas se caracterizaron mediante análisis elemental, análisis termogravimétrico (TGA), espectroscopia infrarroja por transformada de Fourier (FT-IR), espectroscopia de absorción atómica y análisis de área superficial (BET) para validar la evidencia de la recuperación del metal. Los resultados indican que el porcentaje de recuperación de cromo total es de 47,62% respecto del material sin carbonizar estableciendo que las mejores variables de carbonización son 700 ∘C y concentración 1:0.20 %p/p por 2 horas. Palabras Clave: Industria curtiembre, carbonización, recuperación, cromo total

Trichomycterus rosablanca (Siluriformes, Trichomycteridae) una especie nueva de bagre hipogeo de los Andes colombianos

Trichomycterus rosablanca is described as a new troglobitic catfish species from caves in southeastern Santander, Colombia. These caves are drained by the Carare River of the Magdalena River basin. The new species is characterized by the advanced condition in the typical troglomorphisms found in other congeneric cave-dwelling species, such as absence of eyes and pigmentation. Trichomycterus rosablanca is diagnosed by the following putative autapomorphies: 1) presence of a circular foramen in the main body of the interopercle, dorsal to the interopercular plate supporting the odontodes, and 2) presence of a single sensory pore in the posteriormost section of the infraorbital canal. Trichomycterus rosablanca can be distinguished from all known Trichomycterus species from Colombia by having the supraorbital canal interrupted in the nasal section, resulting in the pattern of s1, s2, s3, and s6 sensory pores, and the lachrimal/antorbital bone not enclosing the anteriormost section of the infraorbital canal. The genetic distinctiveness of Trichomycterus rosablanca is confirmed by GMYC and genetic distance method analyses of the cytochrome C oxidase subunit I gene sequence. The description of this species places Colombia as the second most diverse country in the continent in terms of number of cave fish species and calls the  attention on the conservation efforts needed to guarantee the permanence of this remarkable diversity of hypogean fishes. Se describe Trichomycterus rosablanca, una especie nueva de bagre troglobio de cuevas en el suroriente de Santander, Colombia. Estas cuevas son drenadas por el río Carare, de la cuenca del río Magdalena. La especie nueva se caracteriza por la condición avanzada en los troglomorfismos típicos encontrados en otros congéneres habitantes de cuevas, como ausencia de ojos y pigmentación. Trichomycterus rosablanca es diagnosticado por las siguientes autapomorfías putativas: 1) presencia de un foramen circular enel cuerpo principal del interopérculo, dorsal a la placa interopercular soportando los odontodes, y 2) presencia de un único poro sensorial en la sección más posterior del canal infraorbital. Trichomycterus rosablanca puede ser distinguida de todas las especies conocidas de Trichomycterus de Colombia por tener el canal supraorbital interrumpido en la sección nasal, resultando en el patrón de poros sensoriales s1, s2, s3 y s6 y el hueso lacrimal/antorbital no encerrando la sección más anterior del canal infraorbital. La identidad genética de Trichomycterus rosablanca es confirmada por análisis GMYC y de distancia genética de la secuencia génica de la subunidad I de la citocromo C oxidasa. La descripción de esta especie ubica a Colombia como el segundo país más diverso en el continente en términos del número de especies de peces cavernícolas y llama la atención sobre los esfuerzos de conservación necesarios para garantizar la permanencia de esta extraordinaria diversidad de peces hipogeos