Phenomenology of a lepton triplet

The most general phenomenological model involving a lepton triplet with hypercharge $\pm 1$ is constructed. A distinctive feature of this model is the prediction of a doubly charged lepton, and a new heavy Dirac neutrino. We study the phenomenology of these exotic leptons in both low-energy experiments and at the LHC. The model predicts FCNC processes such as rare muon decays, which are studied in detail in order to constrain the model parameters. All the decay channels of the exotic leptons are described for a wide range of parameters. It is found that, if the mixing parameters between the exotic and light leptons are not too small ($>10^{-6}$), then they can be observable to a $3-5\sigma$ statistical significance at the 7 TeV LHC with 10-50 fb$^{-1}$ luminosity for a 400 GeV mass, and 14 TeV with 100-300 fb$^{-1}$ luminosity for a 800 GeV mass.Comment: 28 pages, 17 figures. Version to appear in PR

Caracterizacion de la industria mundial de madera aserrada

87 p.La Industria de madera aserrada está influenciada fuertemente por las economías de los países de destino, las tasas de interés, la relación entre el tipo de cambio de las principales monedas y por !os crecimientos poblacionales de los mercados de destino. En la medida que los indicadores económicos sean positivos, el crecimiento de la industria de madera aserrada también lo será. Este dependencia tan marcado por los indicadores económicos y las fluctuaciones de estos, han transformado a esta industria en una Industria muy concentrada, con pocos países que la lideran (Estados Unidos, Canadá, concentran mas del 40% del mercado mundial), y al interior de estos países, son pocas las industrias que participan, las cuales concentran grandes cantidades de bosques, siendo este Ultimo el factor clave de la industria. Lo anterior implica que las concentraciones de capital son altas. elevando las barreras a los nuevos entrantes. Tanto por capital como par la dificultad de contar con bosques, el cual requiere de una larga rotación en años para estar disponible como insumo del proceso de aserrío. Si bien la concentración es alta y difícil para ingresar nuevos competidores, al interior de la Industria existen países emergentes que podrían acercarse a los lideres. principalmente debido que dentro de las amenazas que enfrenta la industria en general, y en particular para los países del hemisferio norte se encuentran las presiones ambientalistas para evitar la corta de los bosques de sectores importantes del hemisferio norte, lo cual, significaría que países emergentes del hemisferio Sur como Chile, Brasil y Nueva Zelanda podrían tener alguna oportunidad. La industria se caracteriza por ser una industria madura, con fuerte rivalidad entre los participantes, !a competencia es por costo y cada compañía debe reducir sus costos operacionales, introduciendo investigación y desarrollo en los procesos productivos, con el objetivo de hacerlos más baratos y llegar al mercado con productos de bajo costo. La economía de escala que se puede Iograr es importante para reducir los costos y, en forma paralela, manejar la eficiencia en los aserraderos, dada la relación estrecha entre eficiencia en el aserrío y costo medio de los productos. La distribución está concentrada en Empresas Traiders de comercialización, tomando una parte significativa del valor, eslabón muy difícil de saltar por los productores, quienes están integrados hacia atrás en la cadena del valor, controlando el factor clavo, es decir el bosque, Las amenazas que la industria enfrenta están dadas por los sustitutos en la construcción de casas y remodelación, siendo este mercado muy importante y atrayente para la industria; los sustitutos que podrían desplazar a la madera aserrada en estos usos son, principalmente, el acero y el plástico. Pero la principal amenaza para toda la industria, la constituyen las presiones que los ambientalistas están ejerciendo sobre las empresas de la industria, evitando la corta de bosques que constituyen los denominados pulmones del mundo y por otro lado la imposibilidad en algunas áreas de seguir plantando bosque comercial en los sectores de bosque nativos degradados. También amenazan con impactar en los costos de explotación, al exigir medidas de protección del media ambiente en los procesos de explotación y cultivos de Ios bosques. Las oportunidades están básicamente dadas por las percepciones de los compradores de desear productos de alta calidad, lo cual podría diferenciar a un producto básicamente con ninguna diferenciación a uno diferenciado en la comercialización del mismo, dándole valor agregado en los servicios de venta y calidad. Esto ultimo podría permitir a los países emergentes colocar en el mercado con una estrategia agresiva de ventas sus productos de calidad y costo mas bajos que los países lideres

The NH3-Abating effect of Slurry Injection as Influenced by Soil Moisture in a Semiarid Arable Soil

Accumulation of large volumes of dilute slurries is considered one of the major problems related to intensive farming (Sommer et al., 2004). In the EU-27, more than half of the total N excretion is applied to croplands due to technical advantages for farmers (e.g. reuse of nutrients). However, the N use efficiency of slurries produced by livestock is low, i.e. only 20-52% of the excreted N is recovered by crops. Much of the remainder can be lost into the atmosphere as ammonia (NH3), nitrous oxide (N2O), dinitrogen (N2) and nitrogen oxides (NOx)

Viscosity measurements of glycerol in a parallel-plate rheometer exposed to atmosphere

Glycerol is a hygroscopic fluid that spontaneously absorbs water vapor from the atmosphere. For applications involving glycerol, care must be taken to avoid exposure to humidity, since its viscosity decreases quickly as water is absorbed. We report experimental measurements of the viscosity of glycerol in a parallel-plate rheometer where the outer interface is exposed to atmosphere. The measurements decrease with time as water is absorbed from the atmosphere and transported throughout the glycerol via diffusion and advection. Measured viscosities drop faster at higher relative humidities, confirming the role of hygroscopicity on the transient viscosities. The rate of viscosity decrease shows a non-monotonic relationship with the rheometer gap height. This behavior is explained by considering the transition from diffusion-dominated transport in the narrow gap regime to the large gap regime where transport is dominated by inertia-driven secondary flows. Numerical simulations of the water absorption and transport confirm this non-monotonic behavior. The experimental viscosity measurements show unexpectedly fast decreases at very small gap heights, violating the parallel-plate, axisymmetric model. We propose that this drop-off may be due to misalignment in the rheometer that becomes non-negligible for small gaps. Theoretical considerations show that secondary flows in a misaligned rheometer dominate the typical secondary inertial flows in parallel-plate rheometers at small gaps. Finally, simulations in a misaligned parallel-plate system demonstrate the same sharp drop-off in viscosity measurements at small gap heights. This modeling can be used to estimate the gap height where misalignment effects dominate the transient glycerol viscosity measurements.Comment: 26 pages, 17 figure

Effect of organic and mineral fertilizers on greenhouse gases emissions from an irrigated maize crop in Madrid Spain

Both solid or liquid OF showed a significant abatement of N2O cumulative emissions in this irrigated Mediterranean cropping area (P < 0.05) comparing to U. Urea-Pig Compost (U-PC) treatment showed the lowest CH4 sink and highest cumulative soil respiration rates (P<05). Considering GHG-GWP, the use of OF can be considered as an advisable practice to mitigate GHG emissions under Mediterranean climatic conditions

Manejo del riego y la fertilización para la mitigación de gases de efecto invernadero y adaptación de un cultivo de maíz en clima mediterráneo

Los inhibidores de la nitrificación y ureasa han demostrado en numerosos ensayos su potencial para mitigar las emisiones de óxido nitroso (N2O) y aumentar los rendimientos bajo condiciones determinadas. Del mismo modo, otras prácticas basadas en un manejo eficiente del riego y la fertilización pueden ser incluso más efectivas a la hora de reducir las pérdidas de N del agrosistema, tal y como se confirmó en un reciente meta-análisis

Greenhouse gas emissions and crop yields under different organic fertilizers and irrigation treatments in a Mediterranean maize field

In this experiment, we aimed to assess the effect of different organic amendments (pig urine (PU); pig urine with the nitrification inhibitor 3,4 dimethylpyrazolephosphate (DMPP, PUI); compost from the solid phase of pig slurry (PC)) compared to urea (U); and two different irrigation systems (sprinkler and drip) on greenhouse gas (GHG) emissions, crop yield and Nitrogen Use Efficiency (NUE) in a maize (Zea mays L.) crop

Chiral phase transition and Anderson localization in the Instanton Liquid Model for QCD

We study the spectrum and eigenmodes of the QCD Dirac operator in a gauge background given by an Instanton Liquid Model (ILM) at temperatures around the chiral phase transition. Generically we find the Dirac eigenvectors become more localized as the temperature is increased. At the chiral phase transition, both the low lying eigenmodes and the spectrum of the QCD Dirac operator undergo a transition to localization similar to the one observed in a disordered conductor. This suggests that Anderson localization is the fundamental mechanism driving the chiral phase transition. We also find an additional temperature dependent mobility edge (separating delocalized from localized eigenstates) in the bulk of the spectrum which moves toward lower eigenvalues as the temperature is increased. In both regions, the origin and the bulk, the transition to localization exhibits features of a 3D Anderson transition including multifractal eigenstates and spectral properties that are well described by critical statistics. Similar results are obtained in both the quenched and the unquenched case though the critical temperature in the unquenched case is lower. Finally we argue that our findings are not in principle restricted to the ILM approximation and may also be found in lattice simulations.Comment: 14 pages, 13 figure

Ammonia emissions from a soil amended with urea and inhibitor of urease activity in a Mediterranean area

Urea and ammonium-based fertilisers are nowadays one of the most important sources of ammonia (NH3) emissions to the atmosphere in Europe. However, little is known about NH3 volatilisation in Mediterranean areas. The aim of the present study was the quantification of NH3 emissions by using the Integrated Horizontal Flux (IHF) method after application of urea with the urease inhibitor N-(n-butyl) thiophosphorie triamide (NBPT) to a semiarid agricultural soil. The field experiment was carried out at "La Poveda" field station in Madrid on a sunflower crop in spring 2006. Urea and a mixture of urea and the inhibitor (0.14%) were surfaee-applied by hand at a rate of 170 kg N ha"' to eircular plots (diam. 40 m). The soil was irrigated with 10 mm of water just after the applieation of urea to dissolve and incorporate it onto the first layer of soil. There were three peaks in the NH3 flux over the duration of the measurement period (36 d). The first peak was associated to irrigation and the others to rainfall events. The total NH3 emission during the whole experiment (36 days) was 17.3 ±5.5kgNH3-N ha"1 in the ease of urea treated soils and 10.0 ± 4.5 kg NHrN ha"' where NBPT was ineluded with the urea