Humic substances-system in the caatinga amazonica near San Carlos de Rio Negro, Venezuela

1. Durch sukzessiven Einsatz verschiedener organischer Lösungsmittel und Natronlauge werden mehrere Huminstoff-Fraktionen gewonnen. Bei den, mit organischen Lösemitteln extrahierten Huminstoff-Fraktionen handelte es sich um Huminsäure-Vorstufen. 2. Die Huminstoffe wurden mit Hilfe chemischer und physikalischer Methoden charakterisiert. 3. Es wurde die Vergesellschaftungvon sauren, durch Huminstoffe gefärbten, sog. Schwarzwässern der Tropen, insbesondere des Rio Negro-Gebietes, mit den sie begleitenden Podsolen nachgewiesen

Children of the Spanish Civil War

In the prolific literature about the Spanish Civil War (1936-1939), the voices of children have remained largely silent and their experiences neglected; yet the lives of thousands of Spanish children were disrupted by the hardships of the long civil war, and their physical, social, moral, and emotional development from childhood to adulthood was complicated by fear, bombings, shocking violence, loneliness, hunger, and the extremes of weather conditions

A Convex Polynomial Force-Motion Model for Planar Sliding: Identification and Application

We propose a polynomial force-motion model for planar sliding. The set of generalized friction loads is the 1-sublevel set of a polynomial whose gradient directions correspond to generalized velocities. Additionally, the polynomial is confined to be convex even-degree homogeneous in order to obey the maximum work inequality, symmetry, shape invariance in scale, and fast invertibility. We present a simple and statistically-efficient model identification procedure using a sum-of-squares convex relaxation. Simulation and robotic experiments validate the accuracy and efficiency of our approach. We also show practical applications of our model including stable pushing of objects and free sliding dynamic simulations.Comment: 2016 IEEE International Conference on Robotics and Automation (ICRA

New records of the genus Pachygrapsus (Crustacea : Decapoda) from the central Mediterranean Sea with a review of its Mediterranean zoogeography

The occurrence of Pachygrapsus maurus and Pachygrapsus transversus is reported from the Maltese Islands for the first time on the basis of one specimen of P. maurus collected in 1990 and numerous recent specimens, and the distribution of the two species is mapped. The controversial presence of P. maurus in Italy is confirmed and two new sites for this species are reported, including the first for the mainland of Italy. The examination of the historical specimen of P. maurus from the Genova area revealed a misidentification of P. transversus; this record could be a result of ship-mediated transport. First notes on the habitat of P. maurus in the central Mediterranean Sea are given. Updated maps of the distribution of P. maurus and P. transversus in the Mediterranean are provided and the zoogeography of these species is revisited.peer-reviewe

The Atmospheric Response to Meridional Shifts of the Gulf Stream SST Front and Its Dependence on Model Resolution

The Gulf Stream (GS) plays a key role in shaping the North Atlantic climate. Moreover, the associated sea surface temperature (SST) front undergoes interannual-to-decadal variability that is thought to force significant atmospheric circulation anomalies. However, general circulation models do not accurately reproduce the atmospheric response to SST front variability as estimated from observations. In this work we analyze the atmospheric response to the GS SST front (GSF) shifts in a multimodel ensemble of atmosphere-only simulations forced with observed SSTs (1950-2014). The atmospheric response is found to be resolution dependent. Only the high-resolution simulations produce a wintertime response similar to observed anomalies. More specifically, (i) analysis of the atmospheric thermodynamic balance close to the GSF showed that the anomalous diabatic heating associated to the GSF displacement is mainly balanced by vertical motion and by meridional transient eddy heat transport (not the case for low-resolution models), while (ii) the large-scale response includes a meridional shift of the North Atlantic eddy-driven jet and storm track homodirectional to the GSF displacement. This atmospheric response is accompanied by changes in low-level baroclinicity close to and north of the GSF, resulting from the oceanic forcing and the zonal atmospheric circulation anomalies respectively. The low-level baroclinicity anomalies lead to changes in baroclinic eddy activity and, ultimately, in the jet via eddy-mean flow interaction. Considering the two-way nature of air-sea interactions, using historical atmosphere-only simulations is a powerful way to isolate the impact of realistic oceanic variability on the atmosphere. Our results suggest that interannual-to-decadal predictability may be higher than what low-resolution models currently indicate

An all-in-one dual band blade antenna for ads-b and 5g communications in uav assisted wireless networks

This paper is aimed at the characterization and manufacturing of an SMA coaxial fed com-pact blade antenna with dual frequency characteristics for broadband applications on board of Unmanned Air Vehicles (UAVs). This antenna is linearly polarized, and it combines the benefits of Automatic Dependent Surveillance-Broadcast (ADS-B) and 5th Generation (5G) communications in one single element, covering both the 1.030–1.090 GHz and the 3.4–3.8 GHz bands thanks to a bent side and a ‘C’ shaped slot within the radiation element. Starting from the simulation outcomes on an ideal ground plane, the results are here extended to a bent ground plane and on two UAV com-mercial CAD models. Details of manufacturing of the antenna in both aluminium and FR-4 substrate materials are presented. The comparison between measurements and simulations is discussed in terms of return loss, bandwidth, gain, and radiation pattern. Results show an antenna with a low profile and a simple structure that can be employed in various wideband communication systems, suiting future UAV assisted 5G networks while being perfectly compliant with forthcoming ADS-B based Detect-And-Avoid (DAA) technologies in Unmanned Aerial Traffic Management (UTM)

GP-SUM. Gaussian Processes Filtering of non-Gaussian Beliefs

This work studies the problem of stochastic dynamic filtering and state propagation with complex beliefs. The main contribution is GP-SUM, a filtering algorithm tailored to dynamic systems and observation models expressed as Gaussian Processes (GP), and to states represented as a weighted sum of Gaussians. The key attribute of GP-SUM is that it does not rely on linearizations of the dynamic or observation models, or on unimodal Gaussian approximations of the belief, hence enables tracking complex state distributions. The algorithm can be seen as a combination of a sampling-based filter with a probabilistic Bayes filter. On the one hand, GP-SUM operates by sampling the state distribution and propagating each sample through the dynamic system and observation models. On the other hand, it achieves effective sampling and accurate probabilistic propagation by relying on the GP form of the system, and the sum-of-Gaussian form of the belief. We show that GP-SUM outperforms several GP-Bayes and Particle Filters on a standard benchmark. We also demonstrate its use in a pushing task, predicting with experimental accuracy the naturally occurring non-Gaussian distributions.Comment: WAFR 2018, 16 pages, 7 figure

Effect of Variety and Climatic Seasonality on Soil Intracellular Enzymatic Activities in Coffee Agroforestry Systems

Most soil physicochemical parameters do not respond immediately to changes in management when compared to microbiological and biochemical ones; the study of biological and biochemical quality of soils can serve as indicators of their general condition. Enzymatic activities are important in the biochemical functioning of soils. In this work, the activity of three intracellular enzymes of the soil was evaluated: dehydrogenase activity, florescein diacetate hydrolysis and arginine deaminase, its seasonal fluctuation and the effect of two coffee varieties Caturra and Catuaí on an agroforestry system. The soil samples were taken during the dry and rainy seasons in two contiguous plots sown with the two coffee varieties and in each one a non-systematic zigzag sampling was carried out. The physical, chemical properties and intracellular enzymatic activities of the soil were determined by the classical methods of analysis and following standard protocols. It was observed that the dehydrogenase activity and hydrolysis of fluorescein diacetate had greater activity in the rainy season regardless of the variety, whereas arginine deaminase showed more activity in the dry season and for the Caturra variety. The intracellular enzymatic activities showed sensitivity to the changes during the sampling period, in soils planted with coffee varieties Caturra and Catuaí