The Walking Brain: factors influencing human gait

Human walking is a standardized, repeatable and rhythmic locomotor act, with biomechanical patterns reported as roughly common to all healthy individuals. However, some gait patterns could be affected by cognitive, social and cultural factors. This mini-review aims at investigating top-down related differences in walking healthy patterns due to the above factors. The reviewed literature reported that socio-economic factors are at the basis of differences in pedestrian walking speed, related to the pace of life: faster speed was found in industrialized countries than in developing ones. Furthermore, it was suggested that the ancient division between men and women in hunters and gatherers, respectively, could be at the basis of gender visual differences and, in turn, in upper body movements during walking, with women walking with a more stable head. Interestingly, changes in gait speed did not affect cortical resources needed for spatial cognition, whereas a cognitive task may affect the gait speed. The most reliable parameters, poorly affected by psycho-social factors, resulted the symmetry of limb movements and the ratio between stance and swing duration. The latter was found close to the irrational number called golden ratio, providing a fractal structure to human gait cycle. Both these parameters are at the basis of the harmony of human walking, a feature maintained also in presence of top-down driven gait modifications

The Revenue Maximization Oligopoly Model: Comment

This is a comment on an article on the revenue maximization hypothesis by William BaumolOligopoly; revenue maximization

Advances in River Hydraulic Characterization

none1The characterization of river hydraulics is very important for the definition of many problems connected with flood and morphodynamical models, including the stability of banks, slopes and sediments transport. These physical aspects are often closely related to the observation scale of hydraulic phenomena. The latter has significant value both for the channel and basin scale. This coupling of scales is now possible due to, for example, modern LiDAR detection techniques, in which topographic surveys (DEMs) are predominant, as well as other topographical survey techniques. River scale hydraulic phenomena and their field measurements represent a new paradigm towards the development of computational procedures for the spatio-temporal scale representation of complex hydraulic phenomena. This Special Issue aims to emphasize new numerical techniques and physical measurements in the field of hydraulic observations at laboratory, channel, and basin scale. Applying channel scale, He et al. [1] analyzed the effect of physical factors on the growth of Chlorella vulgaris on enriched media by the use of orthogonal analysis and response surface methodology. In this context, rivers are also viewed as biological coupled systems, and in particular, this study shows that the growth of C. vulgaris can be regulated by changing physical conditions simultaneously, and the optimization of physical conditions can be applied to biomass production, algae prediction, and acid water treatment in rivers [1]. By the use of channel scale, Licciardello et al. [2] introduced a stream hydro-morphological evaluation, analysis, and monitoring system procedure called IDRAIM, which allows us, on the basis of a number of physically based geomorphological descriptors, us to determine the overall state of physical ’equilibrium’ of a river. This is a study case of Dittaino River (Eastern Sicily, Italy). It is very important, because the assessment of a river’s ecological status, including its hydro-morphological and morphological dynamics, which can be used for the implementation of design models and interventions integrating protection and environmental requalification, requires the evaluation of hydro-morphological state changes. As such, the IDRAIM procedure could help in sustainable river management [2]. Rivers also affect urban drainage scales. The transition from confluence situations can highlight critical elements for an adequate design and management. In this context, Zhang and Lin [3] conducted an experimental study on the influence of drastically varying discharge ratios on bed topography and flow structure at urban channel confluences. This study showed that the drastic change in discharge ratio causes secondary scouring to the equilibrium bed topography in the confluence area. The bed surface in the sand hole, a sand bar drops, and the sediment are transported downstream. In this experiment, although local sand hole and sand ridge were formed in the flow recovery zone downstream, the results may be more suitable for urban channel confluence with relatively large width–depth ratio and small- and medium-sized natural channel confluences [3]. At basin scale, Primavera and Florio [4] introduced a new fixed mass algorithm that allows direct determination of the multi-fractal spectrum of a river network. The hybrid procedure, based on parallel computation, makes possible the direct estimation of the multifractal spectrum and the exponents of the singularities, without going through the Legendre transforms. By correctly estimating the scale exponents, i.e., the right-hand side of a spectrum, the maximum singularity index to be used in flood prediction models can be correctly estimated. MIUH (multifractal instantaneous unit hydrograph) is based exclusively on this parameter, so a technique that drastically reduces the computation time of multifractal spectra allows to validate real-time prediction flood procedures based on geomorphological descriptors [4]. Costabile et al. [5] investigated the effects of DEM depression filling on river drainage patterns and surface runoff generated by 2D rain-on-grid scenarios. The analysis, which is interesting from the point of view of morphological scaling, offers criteria for defining scaling effects from the transition of grid-channels to hydraulically active channels. The core of these transitions is based on models characterized by shallow water equations [5].openDe Bartolo, S.De Bartolo, S

Singularities of Taylor's power law in the analysis of aggregation measures

Taylor's law is a well-known power law (TPL) for analysing the scaling behaviour of many fluctuating physical phenomena in nature. The scaling exponent $b$ of this law forms the basis of the aggregation process to which a precise probability density function corresponds. In some phenomena, TPL behavior with periodic components of the aggregates has been observed for small partitions, especially for physical processes characterized by values of $b=1$ where fluctuation-related aggregation processes are supported by Poissonian distributions. We intend to show that for values of $b$ very close to unity it is possible to find a trend, in the double logarithmic scale, of the TPL that there are `periodic patterns' (components) between variance and mean. This behaviour is found in other binomial-type distributions, of which the Poissonian is a particular case, with mappings characterised by a variance close to 1

Modeling soil system:complexity under your feet

This is an introductory articl

A Geostatistical Approach to Define Guidelines for Radon Prone Area Identification

Radon is a natural radioactive gas known to be the main contributor to natural background radiation exposure and the major leading cause of lung cancer second to smoking. Indoor radon concentration levels of 200 and 400 Bq/m3 are reference values suggested by the 90/143/Euratom recommendation, above which mitigation measures should be taken in new and old buildings, respectively, to reduce exposure to radon. Despite this international recommendation, Italy still does not have mandatory regulations or guidelines to deal with radon in dwellings. Monitoring surveys have been undertaken in a number of western European countries in order to assess the exposure of people to this radioactive gas and to identify radon prone areas. However, such campaigns provide concentration values in each single dwelling included in the sample, while it is often necessary to provide measures of the pollutant concentration which refer to sub-areas of the region under study. This requires a realignment of the spatial data from the level at which they are collected (points) to the level at which they are necessary (areas). This is known as change of support problem. In this paper, we propose a methodology based on geostatistical simulations in order to solve this problem and to identify radon prone areas which may be suggested for national guidelines.Radon Prone Areas, kriging, geostatistical conditional simulation, change of support problem

Plurilingual communication in ELF talk. From exploration to application of ELF-oriented perspectives

Abstract – Speakers from different linguistic and cultural backgrounds have increasingly come into contact on a global scale and have adopted English as a contact language, a lingua franca, in contexts where the language is used for various communicative purposes. It is observed that multilingual speakers, belonging to different “linguacultural backgrounds” (Cogo, Dewey 2012), draw on a variety of linguistic repertoires which are dynamically and creatively exploited and modified during the interaction. As a consequence, innovative usage and forms emerge, therefore offering unique insights to researchers and scholars interested in the study of ELF communication. In the present paper, one aspect of ELF communication will be emphasized; the “accommodation” strategies employed by ELF speakers when they negotiate meaning. In particular, attention will be given to “repair strategies” (Kaur 2011) and “cognates” (Hülmbauer 2011) in ELF interactional practices. The aim is not only to show the “mutually supportive nature” (Seidlhofer 2001) of such strategies but also how the negotiation processes at work are responsible for new lingua franca usage. More in depth investigation into the underlying linguistic and cognitive processes which contribute to the meaning-making process in ELF communication will be suggested. Consequently, an enhanced knowledge of ELF interactional moves will provide new insights into ELT practices where the role of English as a lingua franca is largely underestimated (Dewey 2011). Awareness of ELF theoretical concepts and empirical findings will be useful to expand traditional language teaching horizons and language policies as well as reduce the gap between how teachers perceive language and communication and  how real communication in the global English world currently takes place. The need to re-examine traditional methodological practices will be therefore highlighted

Testing gravity with non-Gaussianity

We show that modified gravity presents distinctive nonlinear features on the Cosmic Microwave Background (CMB) anisotropies comparing with General Relativity (GR). We calculate the contribution to the CMB non-Gaussianity from nonlinear Sachs-Wolfe effect in $f(R)$ gravity and show that, contrary to GR's contribution which is typically $\lesssim \mathcal{O}(1)$, the contribution in $f(R)$ gravity is sensitive to the nonlinear structure of $f(R)$ and can be large in principle. Optimistically, this gives an alternative origin for the possibly observed large CMB non-Gaussianities besides the primordial ones. On the other hand, such nonlinear features can be employed to provide a new cosmological test of $f(R)$ or other modified theories of gravitation, which is unique and independent of previously known tests.Comment: 4 pages, 1 figure, v2 to match the published versio