Elemental analysis of particulate matter by X-ray fluorescence methods: A green approach to air quality monitoring

This review explores X-ray fluorescence (XRF) spectrometry for elemental analysis of particulate matter (PM) for air quality monitoring. The introduction presents PM classification based on size and composition, covering various elemental analysis methods while highlighting the increasing interest in XRF due to its non-destructive, rapid, and green features. The fundamental concepts of XRF and the experimental configurations commonly used are discussed, focusing on Energy Dispersive X-Ray Fluorescence (EDXRF) and Total Reflection X-Ray Fluorescence (TXRF). PM sampling devices and substrate are described, with a specific emphasis on filtering membranes for EDXRF and reflecting substrates for TXRF. Sample preparation strategies and procedures are presented. Qualitative and quantitative analysis is described, with a particular focus on the calibration approaches implemented for PM. Finally, the challenges faced by XRF in becoming a recognized reliable analytical technique for PM analysis, comparable to other standardized techniques for PM filters analysis, while capitalizing on its green advantages

Using Implicit Instructional Cues to Influence False Memory Induction

Previous research has shown that explicit cues specific to the encoding process (endogenous) or characteristic of the stimuli themselves (exogenous) can be used to direct a reader’s attentional resources towards either relational or item-specific information. By directing attention to relational information (and therefore away from item-specific information) the rate of false memory induction can be increased. The purpose of the current study was to investigate if a similar effect would be found by manipulating implicitly endogenous cues. An instructional manipulation was used to influence the perceptual action participants performed on word stimuli during the encoding of DRM list words. Results demonstrated that the instructional conditions that encouraged faster processing also led to an increased rate of false memory induction for semantically related words, supporting the hypothesis that attention was directed towards relational information. This finding supports the impoverished relational processing account of false memory induction. This supports the idea that implicitly endogenous cues, exogenous cues (like font) or explicitly endogenous cues (like training) can direct attentional resources during encoding

The Centre-Periphery Dialectics in Eastern Sicily Retail System. An Exploratory Research

This paper aims at scrutinizing from an historical perspective the deep trans-formations shaped by retail spaces and new consumption patterns challenging long-entrenched dichotomies, such as the centre-periphery one. In particular, the exploratory research explores the territorial reconfiguration of the main Eastern Sicily metropol-itan areas, Catania and Messina, from the lens of the retail geography, namely after the diffusion of new suburban retail formats which have completely upset deeply-rooted relations between urban core and suburban rings

Positrons in Cosmic Rays from Dark Matter Annihilations for Uplifted Higgs Regions in MSSM

We point out that there are regions in the MSSM parameter space which successfully provide a dark matter (DM) annihilation explanation for observed positron excess (e.g. PAMELA), while still remaining in agreement with all other data sets. Such regions (e.g. the uplifted Higgs region) can realize an enhanced neutralino DM annihilation dominantly into leptons via a Breit-Wigner resonance through the CP-odd Higgs channel. Such regions can give the proper thermal relic DM abundance, and the DM annihilation products are compatible with current antiproton and gamma ray observations. This scenario can succeed without introducing any additional degrees of freedom beyond those already in the MSSM.Comment: 11 pages, 9 figure

Concentration of trace elements in raw milk from cows in the southeast of Córdoba province, Argentina

International audienceAbstractIn recent years, trace elements in cow milk have been considered good bioindicators of pollution in the agricultural environment. The aim of the study was to analyze the correlation between trace element content in livestock drinking water and cow milk from dairy farms located in the southeast of Córdoba province, Argentina. Groundwater is the main source of livestock drinking water. According to the results, trace elements were grouped in three categories: (a) those that were in high concentration in phreatic water and in low concentration in deep wells (As, V); (b) those which showed the opposite trend (Cu, Fe, Mn, Zn); and (c) those that were in very low concentrations in all water samples (Cd, Cr, Ni, Pb, and Se). In elements from group (a), a positive correlation between As content in water and in milk was observed. For elements included in group (b), it was observed a higher concentration in milk samples from farms that use deep wells, related with their higher concentrations in water. Cr, Ni, Pb, and Se milk contents are within the ranges reported in other areas. Soil and forage trace element content may contribute to their presence in milk. Since information about transference of trace elements from environmental matrices to milk is very scarce, at national and international levels, further studies are necessary, including speciation in milk and dairy products, to guarantee food safety

Thermal decoupling and the smallest subhalo mass in dark matter models with Sommerfeld-enhanced annihilation rates

We consider dark matter consisting of weakly interacting massive particles (WIMPs) and revisit in detail its thermal evolution in the early universe, with a particular focus on models where the annihilation rate is enhanced by the Sommerfeld effect. After chemical decoupling, or freeze-out, dark matter no longer annihilates but is still kept in local thermal equilibrium due to scattering events with the much more abundant standard model particles. During kinetic decoupling, even these processes stop to be effective, which eventually sets the scale for a small-scale cutoff in the matter density fluctuations. Afterwards, the WIMP temperature decreases more quickly than the heat bath temperature, which causes dark matter to reenter an era of annihilation if the cross-section is enhanced by the Sommerfeld effect. Here, we give a detailed and self-consistent description of these effects. As an application, we consider the phenomenology of simple leptophilic models that have been discussed in the literature and find that the relic abundance can be affected by as much two orders of magnitude or more. We also compute the mass of the smallest dark matter subhalos in these models and find it to be in the range of about 10^{-10} to 10 solar masses; even much larger cutoff values are possible if the WIMPs couple to force carriers lighter than about 100 MeV. We point out that a precise determination of the cutoff mass allows to infer new limits on the model parameters, in particular from gamma-ray observations of galaxy clusters, that are highly complementary to existing constraints from g-2 or beam dump experiments.Comment: minor changes to match published versio

Arsenic levels in bovine tissues in the southeast of the province Córdoba, Argentina

El arsénico es un contaminante natural de aguas subterráneas en una amplia zona de Argentina, en particular el sudeste de la provincia de Córdoba es una de las regiones más afectadas. La información a nivel mundial acerca de la transferencia de arsénico a la cadena agroalimentaria particularmente a productos cárnicos es escasa. En este trabajo, se determinaron las concentraciones de arsénico en riñón, hígado, músculo esquelético y glándula mamaria en bovinos de la zona de estudio. Los órganos donde se registraron las mayores concentraciones de arsénico fueron hígado y riñón. Los niveles hallados en hígado estuvieron entre 27,0 y 46,5 ng/g y en riñón, entre 24,0 y 73,2 ng/g. En las muestras de músculo y glándula mamaria, las concentraciones estuvieron en todos los casos por debajo del límite de detección de la técnica utilizada. Las concentraciones de arsénico en los diferentes tejidos analizados se encontraron dentro de los límites recomendados a nivel nacional.Arsenic is a groundwater contaminant widely distributed in Argentina. One of the most affected area is the southeast of Cordoba province. The information about the transfer of arsenic to the food chain and meat products is scarce. In this study, the concentrations of arsenic in kidney, liver, muscle and udder in cattle in the study area were analyzed. The highest concentrations of arsenic were found in liver and kidney. The levels found in liver ranged from 27.0 to 46.5 ng/g while in kidney, ranged between 24.0 to 73.2 ng /g. In muscle and udder samples arsenic were below the detection limit of the technique in all cases. The levels of arsenic in the analyzed tissues were within the national recommended limits.Fil: Pérez Carrera, Alejo Leopoldo. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Centro de Estudios Transdisciplinarios del Agua; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pérez Gardiner, M. L.. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Centro de Estudios Transdisciplinarios del Agua; ArgentinaFil: Fernandez Cirelli, Alicia. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Centro de Estudios Transdisciplinarios del Agua; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin