The use of methods of compositional data analysis for the separation of geochemical signals in fluvial sediments

<p>Fluvial sediments datasets, similarly as other types of a concentration based data, are typical by their relative nature and therefore they need preprocessing or normalization prior to the main statistical analysis. In the geochemical practice, several normalization methods are used, like a simple normalization of the target element concentration with the concentration of the reference (conservative, lithogenic) one, double normalization or concentration conversion to local enrichment factor. As an alternative to these methods, the approach using the principles of compositional data analysis (CoDA) can be considered.  Instead of the standard statistical analytical methods, like ordinary least squares regression, correlation of principal component analysis (PCA), applied on the raw or the target element normalized concentrations, the CoDA methods consider the relative structure of the whole dataset. CoDA together with the use of robust statistical methods, which are down weighting the influence of the outlying observations, have a potential to provide more accurate results. This property is demonstrated and discussed on the base of dataset from mapping the sediments from the Skalka Reservoir in the Ohře River, Czech Republic, and its tributaries. Mainly the performance of the robust versions of regression, correlation and principal components analysis, respecting the CoDA principles, will be presented and the way to them will be explained. </p>

Reinventing exergy as indicator for resource depletion impacts in LCA

While resource aspects are gaining increasing importance for the sustainability assessment of new technologies, the question of how to assess the depletion of abiotic resources is still controversially discussed. Different methodologies exist for their quantification within life cycle assessment (LCA). Among them, thermodynamic approaches have the advantage of considering aspects of absolute quantity (reserves or amount of a substance contained in total in earth’s crust) and of quality (concentration of the target element in the mined resource), making them a potentially appealing approach for assessing resource depletion. However, existing approaches are either far from the original thermodynamic idea of exergy or far too complex and not applicable for resource accounting. This work briefly discusses the suitability of exergy-based approaches for resource assessment, and then suggests a simple but comprehensive methodology for quantifying resource depletion related with the concept of chemical concentration exergy (MDPces). It provides a calculation approach for quantifying the MDPces and estimates the corresponding values for some representative key metals.

Modular integrated thermal control system in scientific experimental express rack on space station

As an important mission of space stations, space science experiment usually requires effective temperature control measures. Scientific experimental express rack (ER) is a general design for space science experiment. In some space scientific experiments, the temperature of local target element or surrounding exceed heat sink temperature range, effective heating and cooling measures are required. Thermoelectric cooler (TEC) has high reliability and low complexity, which is applicable for temperature control in low gravity conditions. In the ER, the entire surrounding is indirectly heated or cooled by the ambient air, local target element surface is heated or cooled by liquid, TEC is thermal competent for ER thermal control attributed to the low complexity and high reliability, which can enlarge the temperature range of air and liquid. In this paper, a modular integrated thermal control system (MITCS) is designed for a specific ER, which has liquid assembly (LA), TEC assembly (TECA), heat exchanger assembly (HXA) and air cycle assembly (ACA) to provide target surface cooling and heating, entire surrounding cooling and heating. The thermal performance of MITCS using TEC are analyzed, providing guides for the design of the scientific experimental ER and other thermal systems.

Aging and the Perception of Motion-Defined Form

A single experiment required 26 younger and older adults to discriminate global shape as defined only by differences in the speed of stimulus element rotation. Detection of the target shape required successful perceptual grouping by common fate. A considerable adverse effect of age was found: In order to perceive the target and discriminate its shape with a d’ value of 1.5, the older observers needed target element rotational speeds that were 23.4% faster than those required for younger adults. In addition, as the difference between the rotation speeds of the background and target stimulus elements increased, the performance of the older observers improved at a rate that was only about half of that exhibited by the younger observers. The results indicate that while older adults can perceive global shape defined by similarity (and differences) in rotational speed, their abilities are nevertheless significantly compromised.

Pragmatic influences on sentence integration: Evidence from eye movements

To understand a discourse, readers must rapidly process semantic and syntactic information and extract the pragmatic information these sources imply. An important question concerns how this pragmatic information influences discourse processing in return. We address this issue in two eye movement experiments that investigate the influence of pragmatic inferences on the processing of inter-sentence integration. In Experiments 1a and 1b, participants read two-sentence discourses in Chinese in which the first sentence introduced an event and the second described its consequence, where the sentences were linked using either the causal connective “suoyi” (meaning “so” or “therefore”) or not. The second sentence included a target word that was unmarked or marked using the focus particle “zhiyou” (meaning “only”) in Experiment 1a or “shi” (equivalent to an it-cleft) in Experiment 1b. These particles have the pragmatic function of implying a contrast between a target element and its alternatives. The results showed that while the causal connective facilitated the processing of unmarked words in causal contexts (a connective facilitation effect), this effect was eliminated by the presence of the focus particle. This implies that contrastive information is inferred sufficiently rapidly during reading that it can influence semantic processes involved in sentence integration. Experiment 2 showed that disruption due to conflict between the processing requirements of focus and inter-sentence integration occurred only in causal and not adversative connective contexts, confirming that processing difficulty occurred when a contrastive relationship was not possible.

Heavy Metal and Metalloid Contamination Assessments of Soil around an Abandoned Uranium Tailings Pond and the Contaminations’ Spatial Distribution and Variability

To investigate the heavy metal and metalloid contamination of soil around a Huanan uranium tailings pond, abandoned in 1998, we defined a study area of 41.25 km2 by a natural boundary and targeted 5 elements’ (U, Mn, As, Pb, Cr) single contamination and comprehensive pollution as the assessment contents. First, we collected 205 samples and evaluated them with the contamination factor (CF) method aiming at judging whether the single target element concentration exceeded the local background value and environmental quality standard. We obtained CF1 (the background value of a certain target element as the baseline value) and CF2 (the environmental quality standard for soils as the baseline value). Second, we evaluated the ecological risk of the key pollutant U with the risk assessment code (RAC) method, taking the 27 samples whose CF2 > 1 as examples and concluded that the environmental risk of U was relatively high and should arouse concern. Third, we selected comprehensive pollution index (CPI) to assess the compound pollution degree of five target elements. Fourth, we constructed the U contamination and CPI’s continuous distribution maps with spatial interpolation, from which we worked out the sizes and positions of slightly, moderately and strongly polluted zones. Finally, we analyzed the spatial variability of U and CPI with the aid of a geostatistical variogram. We deduced that the spatial variation of uranium was in close relationship with local topography, and probably precipitation was the driving force of U contamination diffusion, whereas CPI exhibited weak spatial dependence with random characteristics. The above work showed that 3.14 km2 soil near the pond was fairly seriously polluted, and the other 4 elements’ single contaminations were less serious, but the 5 target elements’ cumulative pollution could not be ignored; there were other potential pollution sources besides the uranium tailings pond. Some emergency measures should be taken to treat U pollution, and bioremediation is recommended, taking account into U’s high bioavailability. Further, special alerts should be implemented to identify the other pollution sources.

Towards numerical cognition's origin: insights from day-old domestic chicks

Instead of the scepticism on animal numerical understanding that characterized the first half of the twentieth century, in recent decades, a large and increasing body of the literature has shown that adult animals can master a variety of non-symbolic (in the absence of symbols such as mathematical words) numerical tasks. Nonetheless, evidence proving early numerical abilities in non-human animals was sparse. In this paper, I report the ongoing work to investigate numerical cognition in the day-old domestic chick ( Gallus gallus ). Unlike previous studies on adult animals, chicks can be tested very early in life, which gives us the opportunity to discover the origins of numerical comprehension. Here, I discuss studies revealing that day-old domestic chicks can: (i) discriminate between different numbers of objects; (ii) solve rudimentary arithmetic operations; and (iii) use ordinal information, identifying a target element (e.g. the fourth) in a series of identical elements, on the basis of its serial-numerical position. Some of these abilities are number-specific, while others underlie the interplay between number and continuous extents (continuous-quantity cues that covary with number, such as area and perimeter). These data are discussed in terms of ontogenetic development of mathematical comprehension. This article is part of a discussion meeting issue ‘The origins of numerical abilities’.

Direct lead isotopic analysis of bioethanol by means of multi-collector ICP-mass spectrometry with a total consumption sample introduction system

A method has been developed for the direct (no sample pretreatment and/or isolation of the target element from the sample matrix) Pb isotopic analysis of bioethanol via multi-collector ICP-mass spectrometry (MC-ICP-MS).