Enhancing the smoothness of joint motion induced by functional electrical stimulation using co-activation strategies

The motor precision of today’s neuroprosthetic devices that use artificial generation of limb motion using Functional Electrical Stimulation (FES) is generally low. We investigate the adoption of natural co-activation strategies as present in antagonistic muscle pairs aiming to improve motor precision produced by FES. In a test in which artificial knee-joint movements were generated, we could improve the smoothness of FES-induced motion by 513% when applying co-activation during the phases in which torque production is switched between muscles – compared to no co-activation. We further demonstrated how the co-activation level influences the joint stiffness in a pendulum test.BMBF, 16SV7069K, Bewegungsfähigkeit und Mobilität wiedererlangen - BeMobi

Water Procurement Time and Its Implications for Household Water Demand: Insights from a Water Diary Study in Five Informal Settlements of Pune, India

Many private households spend considerable amounts of time accessing water, for instance by walking to and queuing at public access points, or by filling storage vessels at taps with low flow rates. This time has an opportunity cost, which can be substantial and may impact which water services and quantities of water households demand. In a novel form of diary study, we gathered detailed water consumption and time use data from 50 households in five informal settlements of the Indian metropolis Pune, accompanied by a household survey and in-depth interviews. With the data, we characterize water collection behaviors and assign monetary values to water procurement time. We statistically analyze the effects of time cost on consumed quantities in several two-level mixed effect models. Household members in our sample spend up to several hours each day filling storage vessels, even if a private connection to the piped network is available. Average time cost amounted to the equivalent of 4.23–13.81% of monthly household cash income. Our analyses indicate that procurement time reduces quantitative water demand in a significant way. The households incurring the highest per-unit time cost consumed water quantities below minimum levels recommended for human health. This substantiates that time costs can impede access to water and are a relevant issue for water management and policy

On the foundation of a general theory of stocks

This essay develops the "concept of stocks" – a conceptual notion designed to enable a clearer understanding of the interaction between the dynamics of ecosystems and the economy. The notion of stocks is formulated in a general manner based on set theory. The central attribute of a stock is its temporal durability. Seen thus, stocks are suitable for depicting the influences a system’s history has on its present – and hence for analysing temporal developments. Since permanency is a temporal attribute, the concept of stocks is not specifically limited to individual scientific disciplines and is suitable for interdisciplinary analysis. The notion is applied to economic and ecological examples and generalised for stochastic sets. The hierarchical structure of actual ecological-economic systems can be analysed by distinguishing the stock perspective from a system view. The theory of stocks is a building block for the conceptual foundations of ecological economics

Socioeconomic surveys on private tanker water markets in Jordan: objectives, design and methodology

[Background and survey objectives] In Jordan, which is one of the water poorest countries in the world, water supply is generally intermittent. As a consequence, water supplied by private water vendors via tanker trucks is an important source of drinking water for many Jordanians. The impacts of partially illegal private tanker water markets on sustainable water supply in Jordan’s cities are manifold and complex. The markets significantly contribute to the welfare of commercial establishments and households. However, they also have strong negative impacts on sustainability for example through groundwater depletion. A deepened understanding of emergence, spreading, and functioning of private tanker water markets in Jordanian cities is a precondition for developing policies and interventions towards more sustainable water supply regimes. The study of publicly available data and reports on private tanker water markets in Jordan revealed that there is a need for empirical data and investigations on the supply side of private tanker water as well as on the demand side, especially in terms of commercial establishments who are the major customers of tanker water within cities. Against this background, in the period from September 2015 to October 2016 five mostly quantitative surveys were conducted within the Stanford-led Belmont Forum "Jordan Water Project (JWP)" in order to collect socioeconomic as well as physical and technical data about private tanker water supply and demand in three different Jordanian cities. The objective of the surveys is to provide an empirical basis for two major fields of investigation: * Socioeconomic studies (e.g. market analyses) on the impacts of private tanker water markets on water supply in the city of Amman with a focus on sustainability issues. * Modelling studies on private tanker water markets in Jordan as part of a hydro-economic model on freshwater resources sustainability in Jordan (e.g. estimation of demand functions for piped and tanker water of commercial establishments, simulation of partially illegal markets of private tanker water providers, spatial statistical analyses of commercial water consumption). Jordan’s capital Amman was the location of three surveys targeted at the following key market actors of tanker water: (i) operators of private wells selling water to private water tankers, (ii) water tanker drivers purchasing water from private wells and delivering the water throughout the city of Amman and (iii) commercial establishments using piped and/or tanker water. In order to broaden the empirical basis for advanced modelling studies and simulations on the country level the survey with commercial establishments was repeated in a slightly modified version with (iv) commercial establishments in the city of Irbid and (v) commercial establishments in the city of Ajloun. In this discussion paper the design and methodology of all five surveys is described in detail. For the Amman surveys in addition the survey locations and the spatial distribution of interviews are specified and represented by GIS maps

Eine allgemeine Theorie der Bestände

Im vorliegenden Aufsatz wird ein Begriffskonzept entwickelt, das zum besseren Verständnis des Zusammenspiels der Dynamiken von Ökosystemen und Wirtschaft dient: das Konzept des Bestandes. Der Bestandsbegriff wird allgemein mengentheoretisch formuliert. Die zentrale Eigenschaft eines Bestandes liegt in seiner zeitlichen Dauerhaftigkeit. Damit eignen sich Bestände zur Abbildung von Einflüssen, die die Vergangenheit von Systemen auf deren Gegenwart ausübt, und damit zur Analyse von zeitlichen Entwicklungen. Da Beständigkeit eine Eigenschaft in der Zeit darstellt, ist das Konzept des Bestandes nicht spezifisch auf den Gegenstandsbereich einzelner wissenschaftlicher Disziplinen beschränkt und so für die interdisziplinäre Analyse geeignet. Der Begriff wird auf ökonomische und ökologische Beispiele angewandt und dabei auf stochastische Mengen verallgemeinert. Durch die Abgrenzung der Bestandsperspektive von einer Systemsicht kann die hierarchische Struktur realer ökologisch-ökonomischer Systeme analysiert werden. Die Theorie der Bestände stellt einen Baustein für die konzeptionellen Grundlagen der Ökologischen Ökonomie dar. --Dynamik,Beständigkeit,System,Zeitskalen,Population,Persistenz

Traveling Wave Magnetic Particle Imaging for determining the iron-distribution in rock: Traveling Wave Magnetic Particle Imaging for determining the iron-distribution in rock

Determining the composition of solid materials is of high interest in areas such as material research or quality assurance. There are several modalities at disposal with which various parameters of the material can be observed, but of those only magnetic resonance imaging (MRI) or computer tomography (CT) offer anon-destructive determination of material distribution in 3D. A novel non-destructive imaging method is Magnetic Particle Imaging (MPI), which uses dynamic magnetic fields for a direct determination of the distribution of magnetic materials in 3D. With this approach, it is possible to determine and differentiate magnetic and non-magnetic behaviour. In this paper, the first proof-of-principle measurements of magnetic properties in solid environments are presented using a home-built traveling wave magnetic particle imaging scanner

Feedback control of arm movements using Neuro-Muscular Electrical Stimulation (NMES) combined with a lockable, passive exoskeleton for gravity compensation

Within the European project MUNDUS, an assistive framework was developed for the support of arm and hand functions during daily life activities in severely impaired people. This contribution aims at designing a feedback control system for Neuro-Muscular Electrical Stimulation (NMES) to enable reaching functions in people with no residual voluntary control of the arm and shoulder due to high level spinal cord injury. NMES is applied to the deltoids and the biceps muscles and integrated with a three degrees of freedom (DoFs) passive exoskeleton, which partially compensates gravitational forces and allows to lock each DOF. The user is able to choose the target hand position and to trigger actions using an eyetracker system. The target position is selected by using the eyetracker and determined by a marker-based tracking system using Microsoft Kinect. A central controller, i.e., a finite state machine, issues a sequence of basic movement commands to the real-time arm controller. The NMES control algorithm sequentially controls each joint angle while locking the other DoFs. Daily activities, such as drinking, brushing hair, pushing an alarm button, etc., can be supported by the system. The robust and easily tunable control approach was evaluated with five healthy subjects during a drinking task. Subjects were asked to remain passive and to allow NMES to induce the movements. In all of them, the controller was able to perform the task, and a mean hand positioning error of less than five centimeters was achieved. The average total time duration for moving the hand from a rest position to a drinking cup, for moving the cup to the mouth and back, and for finally returning the arm to the rest position was 71 s.EC/FP7/248326/EU/MUltimodal Neuroprostesis for Daily Upper limb Support/MUNDU

MUNDUS project : MUltimodal neuroprosthesis for daily upper limb support

Background: MUNDUS is an assistive framework for recovering direct interaction capability of severely motor impaired people based on arm reaching and hand functions. It aims at achieving personalization, modularity and maximization of the user’s direct involvement in assistive systems. To this, MUNDUS exploits any residual control of the end-user and can be adapted to the level of severity or to the progression of the disease allowing the user to voluntarily interact with the environment. MUNDUS target pathologies are high-level spinal cord injury (SCI) and neurodegenerative and genetic neuromuscular diseases, such as amyotrophic lateral sclerosis, Friedreich ataxia, and multiple sclerosis (MS). The system can be alternatively driven by residual voluntary muscular activation, head/eye motion, and brain signals. MUNDUS modularly combines an antigravity lightweight and non-cumbersome exoskeleton, closed-loop controlled Neuromuscular Electrical Stimulation for arm and hand motion, and potentially a motorized hand orthosis, for grasping interactive objects. Methods: The definition of the requirements and of the interaction tasks were designed by a focus group with experts and a questionnaire with 36 potential end-users. Five end-users (3 SCI and 2 MS) tested the system in the configuration suitable to their specific level of impairment. They performed two exemplary tasks: reaching different points in the working volume and drinking. Three experts evaluated over a 3-level score (from 0, unsuccessful, to 2, completely functional) the execution of each assisted sub-action. Results: The functionality of all modules has been successfully demonstrated. User’s intention was detected with a 100% success. Averaging all subjects and tasks, the minimum evaluation score obtained was 1.13 ± 0.99 for the release of the handle during the drinking task, whilst all the other sub-actions achieved a mean value above 1.6. All users, but one, subjectively perceived the usefulness of the assistance and could easily control the system. Donning time ranged from 6 to 65 minutes, scaled on the configuration complexity. Conclusions: The MUNDUS platform provides functional assistance to daily life activities; the modules integration depends on the user’s need, the functionality of the system have been demonstrated for all the possible configurations, and preliminary assessment of usability and acceptance is promising

The Epistemic Status of Processing Fluency as Source for Judgments of Truth

This article combines findings from cognitive psychology on the role of processing fluency in truth judgments with epistemological theory on justification of belief. We first review evidence that repeated exposure to a statement increases the subjective ease with which that statement is processed. This increased processing fluency, in turn, increases the probability that the statement is judged to be true. The basic question discussed here is whether the use of processing fluency as a cue to truth is epistemically justified. In the present analysis, based on Bayes’ Theorem, we adopt the reliable-process account of justification presented by Goldman (1986) and show that fluency is a reliable cue to truth, under the assumption that the majority of statements one has been exposed to are true. In the final section, we broaden the scope of this analysis and discuss how processing fluency as a potentially universal cue to judged truth may contribute to cultural differences in commonsense beliefs