First Principles Calculations of Fe on GaAs (100)

We have calculated from first principles the electronic structure of 0.5 monolayer upto 5 monolayer thick Fe layers on top of a GaAs (100) surface. We find the Fe magnetic moment to be determined by the Fe-As distance. As segregates to the top of the Fe film, whereas Ga most likely is found within the Fe film. Moreover, we find an asymmetric in-plane contraction of our unit-cell along with an expansion perpendicular to the surface. We predict the number of Fe 3d-holes to increase with increasing Fe thickness on $p$-doped GaAs.Comment: 9 pages, 14 figures, submitted to PR

Analysis of Microplastics in Food Samples

This chapter presents a compilation of the analytical techniques used to detect and analyze microplastics in food. A detailed description of microplastics found in different samples is provided as well as an estimate of the annual intake of these particles. A total of 22–37 milligrams of microplastics per year was found. The factors that can influence the presence of particles in food, especially table salt, are discussed, showing that a background presence of microplastics in the environment can explain a large amount of experimental data.Support for this work was provided by the CTQ2016-76608-R project from the Ministry of Economy, Industry and Competitiveness (Spain) and by the University of Alicante under the project UAUSTI18-06

Phenomenology After Conceptual Art

The reception of phenomenology in art criticism reached its apex in the mid-1960s in its application to Minimalism in the United States. The focus was on the embodied, direct perceptual experience of Minimalist sculpture, but in light of Conceptual art’s ‘dematerialised’ practices, which developed as the decade progressed, the interest in phenomenology waned. This essay looks at the history of this reception and presents Merleau-Ponty’s late ontological work as a corrective to an inadequate understanding of phenomenology in critical discourses on art at the time. It argues that the late Merleau-Ponty offers tools for an effective critique of early conceptualism’s idealism, as well as a basis on which the ‘dematerialised’ and dispersed ontology of the art work shared by both Conceptual and more recent Post-Conceptual practices can be investigated

Variação espacial de cátions, ânions e variáveis físico-químicas no rio Solimões-Amazonas entre Manaus e Jutaí, bacia amazônica

Cátions e ânions majoritários são espécies químicas de grande importância nos diversos compartimentos aquáticos, porém, pouco abordados de forma exclusiva na bacia amazônica. Neste sentido, o objetivo deste estudo foi avaliar a dinâmica espacial de Na+, Ca2+, K+, Mg2+, Cl- e SO4 2- em um trecho do rio Solimões-Amazonas, levando-se em consideração a alcalinidade, potencial hidrogeniônico (pH), condutividade elétrica (CE), sólidos totais em suspensão (STS) e carbono orgânico total (COT). As coletas foram realizadas em maio, julho e setembro de 2012 em sete pontos na calha principal do rio Solimões-Amazonas e na foz de alguns dos principais tributários: rios Jutaí, Juruá, Japurá e Purus. Os cátions e ânions foram analisados por cromatografia de íons, STS por gravimetria, pH por potenciometria, alcalinidade por titulação potenciométrica, CE por condutimetria e o COT por oxidação catalítica por combustão. As concentrações médias dos cátions seguiram esta ordem Ca2+>Na+>Mg2+>K+ e dos ânions SO4 2->Cl-. De montante à jusante a tendência foi diminuição nas concentrações de cátions e ânions, das variáveis pH, CE, STS e alcalinidade, além do aumento das concentrações de COT. O presente estudo evidenciou mudanças nas características químicas sofridas pelo rio Solimões em seu curso. O aporte dos tributários pode ser apontado como um dos fatores responsáveis por essas modificações

Biodiversity inventories in high gear: DNA barcoding facilitates a rapid biotic survey of a temperate nature reserve

Comprehensive biotic surveys, or ‘all taxon biodiversity inventories’ (ATBI), have traditionally been limited in scale or scope due to the complications surrounding specimen sorting and species identification. To circumvent these issues, several ATBI projects have successfully integrated DNA barcoding into their identification procedures and witnessed acceleration in their surveys and subsequent increase in project scope and scale. The Biodiversity Institute of Ontario partnered with the rare Charitable Research Reserve and delegates of the 6th International Barcode of Life Conference to complete its own rapid, barcode-assisted ATBI of an established land trust in Cambridge, Ontario, Canada

Identification of sandstone-related rocks composition using the X-ray analysis

The article presents knowledge based on investigation of sandstones or siltstones composition from the Paleogene flysch terrains in North-East Slovakia. Samples of frequently crumbling clastic rocks were commonly considered to be close to sandstones, composed by predominant quartz. The set of such samples, belonging to Dukla Unit Sandstones were analyzed using the XRD analyses. Beside of quartz the diffraction patterns gave the evidence in significant carbonate share with some minor to minute feldspars, mica and chlorite contents. Among majority of analyzed samples we distinguish three groups of sandstones: (1) with the abundant calcite admixture, (2) the sandstones which contain meaning dolomite portion. The group (3) is representing the samples is formed the same by quartz as by both of carbonates, each of them could form important up to prevailed mineral component. Comparison of analyzed samples mineral composition shows remarkable trend of higher calcite and dolomite contents in younger clastic sediments

Geochemical determination of hydrothermal mineralization of Pieniny Klippen Belt rocks

Wykonano prace terenowe oraz badania mineralogiczno-petrograficzne i chemiczne żyłek występujących w skałach z otoczenia Pienińskiego Pasa Skałkowego, po stronie polskiej i słowackiej. Miały one na celu rozpoznanie obecnych w nich objawów procesów wtórnej mineralizacji skał a zwłaszcza ich składu chemicznego, w tym szczególnie pierwiastków śladowych w powszechnych w tym rejonie żyłkach tnących różne rodzaje skał. Podjęto próbę wstępnego rozpoznania ewentualnych aureoli geochemicznych, zarówno w otoczeniu pienińskich andezytów, jak i Pienińskiego Pasa Skałkowego. Praca jest efektem współpracy naukowej Wydziału Geologii, Geofizyki i Ochrony Środowiska AGH (Polska) z Uniwersytetem Technicznym w Koszycach (Słowacja).Field study as well as, mineralogical-petrological and chemical investigations of veins, occurring in rocks surrounding the Pieniny Clipping Belt, on both Poland and Slovakia sides, have been performed. Their aim was to recognize the symptoms of the secondary mineralization of the rocks, as well as their chemical composition, particularly, the presence of trace elements. The attempt of initial recognition of the possible geochemical aureoles in surroundings of both Pieniny andesites and Pieniny Clipping Belt has been undertaken. According to the chemical analyses of the vein mineral constituents, separated from the rocks, the increased concentrations of metals, particularly Pb, have been found. The determined concentrations of Pb were six times higher than observed in the rocks of andesite type, or even ten times as high as those in sandstones. Within Pieniny region some geochemical associations of elements like Fe, Cu, Pb, Zn have been found, especially, in rocks hydrothermally altered