Cambios en la física del suelo e incrementos de la escorrentía y la erosión tras un incendio forestal

[Resumen] Los cambios en las propiedades físicas del suelo después de un incendio forestal, determinan una menor capacidad de infiltración y son responsables del incremento de escorrentía y erosión. El siguiente artículo analiza la textura, la porosidad y la estabilidad estructural del suelo de un bosque quemado en 1993. Se analizan también las diferencias que las intensidades del fuego pudieron tener en estas propiedades. Estos aspectos son comparados entre una parcela control de bosque y tres áreas afectadas por diferentes intensidades del incendio. Se han obtenido tasas de escorrentía hasta 8 veces superiores en la zona de intensidad alta, y tasas de erosión 30 veces superiores en episodios concretos de precipitación. La suma de los efectos producidos en la física del suelo, así como la desprotección del mismo por parte de la vegetación explicarían el aumento de la escorrentía y la erosión.[Abstract] Runoff and erosion increment after forest fires are, in part, a consequence of changes in the physical properties of the soil. This paper analizes the texture, porosity and aggregate stability of the soil of a forest burnt in 1993. The differences of these properties as a consequence of different fire intensities are also analized. As a consequence of these changes the soil has less infiltration capacity, and there is an increment of runoff and erosiono These two aspects are compared between a control plot in the forest, and in three areas afected with different fire intensity. Runoff increases 8 times and erosion 30 times in the high fire intensity area during concret rainfal1 events. The effects of fire in the physical properties plus the burnt of vegetation explain the increases of runoff and erosion

The highly ionized disk wind of GRO J1655-40

Aims: The galactic superluminal microquasar GRO J1655-40 started a new outburst in February 2005, after seven years in quiescence, rising to a high/soft state in March 2005. In this paper we study the X-ray spectra during this rise. Methods: We observed GRO J1655-40 with XMM-Newton, on 27 February 2005, in the low/hard state, and on three consecutive days in March 2005, during the rise of the source to its high/soft state. The EPIC-pn camera was used in the fast-read Burst mode to avoid photon pile-up. Results: First, we contributed to the improvement of the calibration of the EPIC-pn, since the high flux received from the source required some refinements in the correction of the Charge Transfer Efficiency of the camera.Second, we find that the X-ray spectrum of GRO J1655-40 is dominated in the high/soft state by the thermal emission from the accretion disk, with an inner radius of 13-14(D/3.2kpc)km and a maximum temperature of 1.3 keV. Two absorption lines are detected in the EPIC-pn spectra, at 6.7-6.8 and 7.8-8.0 keV, which can be identified either as blended Fe XXV and Fe XXVI K-alpha and K-beta lines, or as blueshifted Fe XXV. We find no orbital dependence on the X-ray properties, which provides an upper limit for the inclination of the system of 73 degr. The RGS spectrometers reveal interstellar absorption features at 17.2AA, 17.5AA (Fe L edges) and 23.54AA (OI K-alpha). Finally, while checking the interstellar origin of the OI line, we find a general correlation of the OI K-alpha line equivalent width with the hydrogen column density using several sources available in the literature.Comment: 10 pages, 7 figures, 4 tables. Revised version with important change

Military spending and economic growth in China: a regime-switching analysis

This article has been made available through the Brunel Open Access Publishing Fund.This article investigates the impact of military spending changes on economic growth in China over the period 1953 to 2010. Using two-state Markov-switching specifications, the results suggest that the relationship between military spending changes and economic growth is state dependent. Specifically, the results show that military spending changes affect the economic growth negatively during a slower growth-higher variance state, while positively within a faster growth-lower variance one. It is also demonstrated that military spending changes contain information about the growth transition probabilities. As a policy tool, the results indicate that increases in military spending can be detrimental to growth during slower growth-higher growth volatility periods. © 2014 © 2014 The Author(s). Published by Taylor & Francis

Insulin degradation by adipose tissue is increased in human obesity

White adipose tissue samples from obese and lean patients were used for the estimation ofinsulin protease and insulin:glutathione transhydrogenase using 1251-labeled insulin. There was no activity detected in the absence of reduced glutathione, which indicates that insulin is cleaved in human adipose "tissue through reduction of the disulfide bridge between the chains. O bese patients showed higher transhydrogenase activity (per U tissue protein wt, per U tissue wt, and in the total adipose tissue mass) than the lean group. There is a significant correlation between the activity per U tissue wt, and protein and total activity in the whole adipose tissue with respect to body mass index, with a higher activity in obese patients. The potential ofinsulin cleavage by adipose tissue in obese patients was a mean 5.6-fold higher than that in controla. The coexistence of high insulinemia and high cleavage capability implies that insulin secretion and turnover are increased in the o bese. Thus, white adipose tissue may be crucial in the control of energy availability through modulation ofinsulin cleavage

Probability-Based Dynamic Time Warping for Gesture Recognition on RGB-D Data

Dynamic Time Warping (DTW) is commonly used in gesture recognition tasks in order to tackle the temporal length variability of gestures. In the DTW framework, a set of gesture patterns are compared one by one to a maybe infinite test sequence, and a query gesture category is recognized if a warping cost below a certain threshold is found within the test sequence. Nevertheless, either taking one single sample per gesture category or a set of isolated samples may not encode the variability of such gesture category. In this paper, a probability-based DTW for gesture recognition is proposed. Different samples of the same gesture pattern obtained from RGB-Depth data are used to build a Gaussian-based probabilistic model of the gesture. Finally, the cost of DTW has been adapted accordingly to the new model. The proposed approach is tested in a challenging scenario, showing better performance of the probability-based DTW in comparison to state-of-the-art approaches for gesture recognition on RGB-D data

Acoustic properties of colloidal crystals

We present a systematic study of the frequency band structure of acoustic waves in crystals consisting of nonoverlapping solid spheres in a fluid. We consider colloidal crystals consisting of polystyrene spheres in water, and an opal consisting of close-packed silica spheres in air. The opal exhibits an omnidirectional frequency gap of considerable width; the colloidal crystals do not. The physical origin of the bands are discussed for each case in some detail. We present also results on the transmittance of finite slabs of the above crystals.Comment: 7 pages, 9 figures, prb approve

SQG-Differential Evolution for difficult optimization problems under a tight function evaluation budget

In the context of industrial engineering, it is important to integrate efficient computational optimization methods in the product development process. Some of the most challenging simulation-based engineering design optimization problems are characterized by: a large number of design variables, the absence of analytical gradients, highly non-linear objectives and a limited function evaluation budget. Although a huge variety of different optimization algorithms is available, the development and selection of efficient algorithms for problems with these industrial relevant characteristics, remains a challenge. In this communication, a hybrid variant of Differential Evolution (DE) is introduced which combines aspects of Stochastic Quasi-Gradient (SQG) methods within the framework of DE, in order to improve optimization efficiency on problems with the previously mentioned characteristics. The performance of the resulting derivative-free algorithm is compared with other state-of-the-art DE variants on 25 commonly used benchmark functions, under tight function evaluation budget constraints of 1000 evaluations. The experimental results indicate that the new algorithm performs excellent on the 'difficult' (high dimensional, multi-modal, inseparable) test functions. The operations used in the proposed mutation scheme, are computationally inexpensive, and can be easily implemented in existing differential evolution variants or other population-based optimization algorithms by a few lines of program code as an non-invasive optional setting. Besides the applicability of the presented algorithm by itself, the described concepts can serve as a useful and interesting addition to the algorithmic operators in the frameworks of heuristics and evolutionary optimization and computing

I Just Ran Four Million Regressions

In this paper I try to move away from the Extreme Bounds method of identifying" Instead of analyzing the" extreme bounds of the estimates of the coefficient of a particular variable distribution. My claim in this paper is that, if we do this, the picture emerging from the" empirical growth literature is not the pessimistic Robust" that we get with the" extreme bound analysis. Instead, we find that a substantial number of variables can be found" to be strongly related to growth.

Re-examining the consumption-wealth relationship : the role of model uncertainty

This paper discusses the consumption-wealth relationship. Following the recent influential workof Lettau and Ludvigson [e.g. Lettau and Ludvigson (2001), (2004)], we use data on consumption, assets andlabor income and a vector error correction framework. Key …ndings of their work are that consumption doesrespond to permanent changes in wealth in the expected manner, but that most changes in wealth are transitoryand have no e¤ect on consumption. We investigate the robustness of these results to model uncertainty andargue for the use of Bayesian model averaging. We …nd that there is model uncertainty with regards to thenumber of cointegrating vectors, the form of deterministic components, lag length and whether the cointegratingresiduals a¤ect consumption and income directly. Whether this uncertainty has important empirical implicationsdepends on the researcher's attitude towards the economic theory used by Lettau and Ludvigson. If we workwith their model, our findings are very similar to theirs. However, if we work with a broader set of models andlet the data speak, we obtain somewhat di¤erent results. In the latter case, we …nd that the exact magnitudeof the role of permanent shocks is hard to estimate precisely. Thus, although some support exists for the viewthat their role is small, we cannot rule out the possibility that they have a substantive role to play

Hidden costs of antiretroviral treatment: the public health efficiency of drug packaging

While the overall percentage of unused antiretroviral medicines returned to the hospital pharmacy is low, their cost is quite high. Adverse events, treatment failure, pharmacokinetic interactions, pregnancy, or treatment simplification are common reasons for unplanned treatment changes. Socially inefficient antiretroviral packages prevent the reuse of drugs returned to the hospital pharmacy. We defined antiretroviral package categories based on the excellence of drug packaging and analyzed the number of pills and costs of drugs returned during a period of 1 year in a hospital-based HIV unit attending to 2,413 treated individuals. A total of 6,090 pills (34% of all returned antiretrovirals) - with a cost of 47,139.91 € - would be totally lost, mainly due to being packed up in the lowest efficiency packages. Newer treatments are packaged in low-excellence categories of packages, thus favoring the maintenance of these hidden costs in the near future. Therefore, costs of this low-efficiency drug packaging, where medication packages are started but not completed, in high-cost medications are substantial and should be properly addressed. Any improvement in the packaging by the manufacturer, and favoring the choice of drugs supplied through efficient packages (when efficacy, toxicity, and convenience are similar), should minimize the treatment expenditures paid by national health budgets