Forestry, geology and hydrological investigations from ERTS-1 imagery in two areas of Ecuador, South America

The author has identified the following significant results. In the Oriente area, well-drained forests containing commercially valuable hardwoods can be recognized confidently and delineated quickly on the ERTS imagery. In the tropical rainforest, ERTS can provide an abundance of inferential information about large scale geologic structures. ERTS imagery is better than normal aerial photography for recognizing linears. The imagery is particularly useful for updating maps of the distributary system of the Guagas River Basin and of any other river with a similarly rapid changing channel pattern

On the Saturation of Astrophysical Dynamos: Numerical Experiments with the No-cosines flow

In the context of astrophysical dynamos we illustrate that the no-cosines flow, with zero mean helicity, can drive fast dynamo action and study the dynamo's mode of operation during both the linear and non-linear saturation regime: It turns out that in addition to a high growth rate in the linear regime, the dynamo saturates at a level significantly higher than normal turbulent dynamos, namely at exact equipartition when the magnetic Prandtl number is on the order of unity. Visualization of the magnetic and velocity fields at saturation will help us to understand some of the aspects of the non-linear dynamo problem.Comment: 8 pages, 5 figures, submitted to the proceedings of "Space Climate 1" to be peer-reviewed to Solar Physic

Millimetre continuum observations of comet C/2009 P1 (Garradd)

Little is known about the physical properties of the nuclei of Oort cloud comets. Measuring the thermal emission of a nucleus is one of the few means for deriving its size and constraining some of its thermal properties. We attempted to measure the nucleus size of the Oort cloud comet C/2009 P1 (Garradd). We used the Plateau de Bure Interferometer to measure the millimetric thermal emission of this comet at 157 GHz (1.9 mm) and 266 GHz (1.1 mm). Whereas the observations at 266 GHz were not usable due to bad atmospheric conditions, we derived a 3-sigma upper limit on the comet continuum emission of 0.41 mJy at 157 GHz. Using a thermal model for a spherical nucleus with standard thermal parameters, we found an upper limit of 5.6 km for the radius. The dust contribution to our signal is estimated to be negligible. Given the water production rates measured for this comet and our upper limit, we estimated that Garradd was very active, with an active fraction of its nucleus larger than 50%.Comment: Accepted for publication in Astronomy & Astrophysics. 5 pages, 2 figure

Complex organic molecules in comets C/2012 F6 (Lemmon) and C/2013 R1 (Lovejoy): detection of ethylene glycol and formamide

A spectral survey in the 1 mm wavelength range was undertaken in the long-period comets C/2012 F6 (Lemmon) and C/2013 R1 (Lovejoy) using the 30 m telescope of the Institut de radioastronomie millim\'etrique (IRAM) in April and November-December 2013. We report the detection of ethylene glycol (CH$_2$OH)$_2$ (aGg' conformer) and formamide (NH$_2$CHO) in the two comets. The abundances relative to water of ethylene glycol and formamide are 0.2-0.3% and 0.02% in the two comets, similar to the values measured in comet C/1995 O1 (Hale-Bopp). We also report the detection of HCOOH and CH$_3$CHO in comet C/2013 R1 (Lovejoy), and a search for other complex species (methyl formate, glycolaldehyde).Comment: Accepted for publication as a Letter in Astronomy and Astrophysic

Nonlinear electron transport in normally pinched-off quantum wire

Nonlinear electron transport in normally pinched-off quantum wires was studied. The wires were fabricated from AlGaAs/GaAs heterostructures with high-mobility two-dimensional electron gas by electron beam lithography and following wet etching. At certain critical source-drain voltage the samples exhibited a step rise of the conductance. The differential conductance of the open wires was noticeably lower than e^2/h as far as only part of the source-drain voltage dropped between source contact and saddle-point of the potential relief along the wire. The latter limited the electron flow injected to the wire. At high enough source-drain voltages the decrease of the differential conductance due to the real space transfer of electrons from the wire in GaAs to the doped AlGaAs layer was found. In this regime the sign of differential magnetoconductance was changed with reversing the direction of the current in the wire or the magnetic field, whet the magnetic field lies in the heterostructure plane and is directed perpendicular to the current. The dependence of the differential conductance on the magnetic field and its direction indicated that the real space transfer events were mainly mediated by the interface scattering.Comment: LaTeX 2e (epl.cls) 6 pages, 3 figure

High-performance network traffic processing systems using commodity hardware

The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-642-36784-7_1The Internet has opened new avenues for information ac- cessing and sharing in a variety of media formats. Such popularity has resulted in an increase of the amount of resources consumed in backbone links, whose capacities have witnessed numerous upgrades to cope with the ever-increasing demand for bandwidth. Consequently, network tra c processing at today's data transmission rates is a very demanding task, which has been traditionally accomplished by means of specialized hard- ware tailored to speci c tasks. However, such approaches lack either of exibility or extensibility|or both. As an alternative, the research com- munity has pointed to the utilization of commodity hardware, which may provide exible and extensible cost-aware solutions, ergo entailing large reductions of the operational and capital expenditure investments. In this chapter, we provide a survey-like introduction to high-performance network tra c processing using commodity hardware. We present the required background to understand the di erent solutions proposed in the literature to achieve high-speed lossless packet capture, which are reviewed and compared

Turbulent Erosion of Magnetic Flux Tubes

Results from a numerical and analytical investigation of the solution of a nonlinear axially symmetric diffusion equation for the magnetic field are presented for the case when the nonlinear dependence of the diffusivity nu(B) on the magnetic field satisfies basic physical requirements. We find that for sufficiently strong nonlinearity (i.e. for sufficiently strong reduction of nu inside the tube) a current sheet is spontaneously formed around the tube within one diffusion timescale. This sheet propagates inwards with a velocity inversely proportional to the ratio of the field strength just inside the current sheet to the equipartition field strength B0/Be, so the lifetime of a tube with constant internal flux density is increased approximately by a factor not exceeding B0/Be, even for infinitely effective inhibition of turbulence inside the tube. Among the applications of these results we point out that toroidal flux tubes in the solar convective zone are subject to significant flux loss owing to turbulent erosion on a timescale of about 1 month, and that turbulent erosion may be responsible for the formation of a current sheet around a sunspot. It is further proposed that, despite the simplifying assumptions involved, our solutions correctly reflect the essential features of the sunspot decay process.Comment: 17 pages, 11 figure

Multiple melt bodies fed the AD 2011 eruption of Puyehue-Cordon Caulle, Chile

Artículo de publicación ISIWithin the volcanological community there is a growing awareness that many large-to smallscale, point-source eruptive events can be fed by multiple melt bodies rather than from a single magma reservoir. In this study, glass shard major-and trace-element compositions were determined from tephra systematically sampled from the outset of the Puyehue-Corden Caulle (PCC) eruption (similar to 1 km(3)) in southern Chile which commenced on June 4th, 2011. Three distinct but cogenetic magma bodies were simultaneously tapped during the paroxysmal phase of this eruption. These are readily identified by clear compositional gaps in CaO, and by Sr/Zr and Sr/Y ratios, resulting from dominantly plagioclase extraction at slightly different pressures, with incompatible elements controlled by zircon crystallisation. Our results clearly demonstrate the utility of glass shard major-and trace-element data in defining the contribution of multiple magma bodies to an explosive eruption. The complex spatial association of the PCC fissure zone with the Liquine-Ofqui Fault zone was likely an influential factor that impeded the ascent of the parent magma and allowed the formation of discrete melt bodies within the sub-volcanic system that continued to independently fractionate.Argentine PIP CONICET 2011 0311 FONCYT PICT 2010 2046 Iniciativa Cientifica Milenio grants P02-51 NC120066 Chilean Fondecyt 115146

Evolución de la relación entre atención primaria y especializada 1992-2001: estudio Delphi

ObjetivoValorar la tendencia en la relación de atención primaria (AP) y especializada (hospital) en 2 momentos diferentes de la reforma sanitaria, al inicio (1992) y tras una fase de consolidación (2001).DiseñoEstudio cualitativo basado en la técnica Delphi modificada.EmplazamientoComunidad Valenciana.ParticipantesSe seleccionó a un total de 196 profesionales de la Comunidad Valenciana (103 coordinadores de AP, 43 directores médicos hospitalarios y de AP, y 50 jefes de servicio de medicina interna/urgencias).ResultadosSe enviaron 196 cuestionarios, con una tasa de respuesta del 38%. Desde AP los problemas se mantienen, con un empeoramiento en la desmotivación del personal sanitario (+1,34), la falta de visión integral del paciente (+1,10) y la masificación asistencial (+1,06), y un mejoría en la presencia de especialistas de ambulatorio no integrados (–1,32). Desde el ámbito hospitalario empeora la falta de visión integral del paciente (+0,51), pero destaca la mejoría generalizada de los problemas, sobre todo la falta de comunicación y diálogo (–1,14). Las soluciones que aumentan su demanda desde AP son una historia clínica única informatizada (+1,50), la elaboración de protocolos comunes (+0,86) y las rotaciones periódicas de los médicos de AP (MAP) por servicios hospitalarios (+0,85), con una disminución de las derivaciones burocráticas a AP (–0,60) y la necesidad de especialistas en AP como consultores (–0,36). Desde el ámbito hospitalario, todas las soluciones disminuyen su valoración y entre ellas destaca facilitar el acceso de MAP para el seguimiento de los pacientes ingresados (–2,44) y la realización de guardias hospitalarias por MAP (–2,30).ConclusionesLos problemas y las soluciones siguen siendo los mismos que en 1992, pero en AP se observa una tendencia a empeorar y en el ámbito hospitalario se detecta una visión más positiva.AimTo evaluate the trends in the inter-professional relationship between primary health care (PHC) and secondary care (hospital) at 2 different moments of the health reform, at its start in 1992 and after a phase of consolidation (2001).DesignObservational study based on modified Delphi technique.SettingValencia Community, Spain.ParticipantsOne hundred and ninety six professionals from Valencia Community were selected (103 PH centre administrators, 43 hospital and PC medical directors, and 50 heads of internal medicine or emergency services).ResultsOne hundred and ninety six questionnaires were sent out, with a response rate of 38%. In PHC problems remained the same, but the following got worse: “lack of motivation” (+1.34), “lack of overall vision of patients” (+1.10), and “overuse of medical services” (+1.06). The existence of non-integrated out-patient specialists got better (–1.32). In hospitals, “lack of overall vision of patients” got worse (+0.51), but in general problems got better, especially in “lack of communication and dialogue” (–1.14). PC increased its demand for “a single computerized clinical record” (+1.50), drawing up of common protocols (+0.86), and periodic rotations of PC doctors through hospitals (+0.85), but bureaucratic referrals to PC (–0.60) and the need for specialists in PC as consultants (-0.36) diminished. In hospitals all solutions showed lower scores, particularly access of PC doctors to monitoring of admitted patients (–2.44) and PC doctors doing hospital cover (–2.30).ConclusionsProblems and solutions from PHC and hospitals remain the same, but there is a trend to the worse in PHC, whereas in hospitals the trend is more positive