269 research outputs found
Sensory Electrical Stimulation Improves Foot Placement during Targeted Stepping Post-Stroke
Proper foot placement is vital for maintaining balance during walking, requiring the integration of multiple sensory signals with motor commands. Disruption of brain structures post-stroke likely alters the processing of sensory information by motor centers, interfering with precision control of foot placement and walking function for stroke survivors. In this study, we examined whether somatosensory stimulation, which improves functional movements of the paretic hand, could be used to improve foot placement of the paretic limb. Foot placement was evaluated before, during, and after application of somatosensory electrical stimulation to the paretic foot during a targeted stepping task. Starting from standing, twelve chronic stroke participants initiated movement with the non-paretic limb and stepped to one of five target locations projected onto the floor with distances normalized to the paretic stride length. Targeting error and lower extremity kinematics were used to assess changes in foot placement and limb control due to somatosensory stimulation. Significant reductions in placement error in the medial–lateral direction (p = 0.008) were observed during the stimulation and post-stimulation blocks. Seven participants, presenting with a hip circumduction walking pattern, had reductions (p = 0.008) in the magnitude and duration of hip abduction during swing with somatosensory stimulation. Reductions in circumduction correlated with both functional and clinical measures, with larger improvements observed in participants with greater impairment. The results of this study suggest that somatosensory stimulation of the paretic foot applied during movement can improve the precision control of foot placement
The European Plate Observing System and the Arctic
The European Plate Observing System (EPOS) aims to integrate existing infrastructures in the solid earth sciences into a single infrastructure, enabling earth scientists across Europe to combine, model, and interpret multidisciplinary datasets at different time and length scales. In particular, a primary objective is to integrate existing research infrastructures within the fields of seismology, geodesy, geophysics, geology, rock physics, and volcanology at a pan-European level. The added value of such integration is not visible through individual analyses of data from each research infrastructure; it needs to be understood in a long-term perspective that includes the time when changes implied by current scientific research results are fully realized and their societal impacts have become clear. EPOS is now entering its implementation phase following a four-year preparatory phase during which 18 member countries in Europe contributed more than 250 research infrastructures to the building of this pan-European vision. The Arctic covers a significant portion of the European plate and therefore plays an important part in research on the solid earth in Europe. However, the work environment in the Arctic is challenging. First, most of the European Plate boundary in the Arctic is offshore, and hence, sub-sea networks must be built for solid earth observation. Second, ice covers the Arctic Ocean where the European Plate boundary crosses through the Gakkel Ridge, so innovative technologies are needed to monitor solid earth deformation. Therefore, research collaboration with other disciplines such as physical oceanography, marine acoustics, and geo-biology is necessary. The establishment of efficient research infrastructures suitable for these challenging conditions is essential both to reduce costs and to stimulate multidisciplinary research.Le système European Plate Observing System (EPOS) vise l’intégration des infrastructures actuelles en sciences de la croûte terrestre afin de ne former qu’une seule infrastructure pour que les spécialistes des sciences de la Terre des quatre coins de l’Europe puissent combiner, modéliser et interpréter des ensembles de données multidisciplinaires moyennant diverses échelles de temps et de longueur. Un des principaux objectifs consiste plus particulièrement à intégrer les infrastructures de recherche existantes se rapportant aux domaines de la sismologie, de la géodésie, de la géophysique, de la géologie, de la physique des roches et de la volcanologie à l’échelle paneuropéenne. La valeur ajoutée de cette intégration n’est pas visible au moyen des analyses individuelles des données émanant de chaque infrastructure de recherche. Elle doit plutôt être considérée à la lumière d’une perspective à long terme, lorsque les changements qu’impliquent les résultats de recherche scientifique actuels auront été entièrement réalisés et que les incidences sur la société seront claires. Le système EPOS est en train d’amorcer sa phase de mise en oeuvre. Cette phase succède à la phase préparatoire de quatre ans pendant laquelle 18 pays membres de l’Europe ont soumis plus de 250 infrastructures de recherche en vue de l’édification de cette vision paneuropéenne. L’Arctique couvre une grande partie de la plaque européenne et par conséquent, il joue un rôle important dans les travaux de recherche portant sur la croûte terrestre en Europe. Cependant, le milieu de travail de l’Arctique n’est pas sans défis. Premièrement, la majorité de la limite de la plaque européenne se trouvant dans l’Arctique est située au large, ce qui signifie que des réseaux marins doivent être aménagés pour permettre l’observation de la croûte terrestre. Deuxièmement, de la glace recouvre l’océan Arctique, là où la limite de la plaque européenne traverse la dorsale de Gakkel, ce qui signifie qu’il faut recourir à des technologies innovatrices pour surveiller la déformation de la croûte terrestre. C’est pourquoi les travaux de recherche doivent nécessairement se faire en collaboration avec d’autres disciplines comme l’océanographie physique, l’acoustique marine et la géobiologie. L’établissement d’infrastructures de recherche efficaces capables de faire face à ces conditions rigoureuses s’avère essentiel, tant pour réduire les coûts que pour stimuler la recherche multidisciplinaire
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Coordinated machine learning and decision support for situation awareness.
For applications such as force protection, an effective decision maker needs to maintain an unambiguous grasp of the environment. Opportunities exist to leverage computational mechanisms for the adaptive fusion of diverse information sources. The current research employs neural networks and Markov chains to process information from sources including sensors, weather data, and law enforcement. Furthermore, the system operator's input is used as a point of reference for the machine learning algorithms. More detailed features of the approach are provided, along with an example force protection scenario
Measurement of the antineutrino neutral-current elastic differential cross section
arXiv:1309.7257v1 [hep-ex
Signatures of arithmetic simplicity in metabolic network architecture
Metabolic networks perform some of the most fundamental functions in living
cells, including energy transduction and building block biosynthesis. While
these are the best characterized networks in living systems, understanding
their evolutionary history and complex wiring constitutes one of the most
fascinating open questions in biology, intimately related to the enigma of
life's origin itself. Is the evolution of metabolism subject to general
principles, beyond the unpredictable accumulation of multiple historical
accidents? Here we search for such principles by applying to an artificial
chemical universe some of the methodologies developed for the study of genome
scale models of cellular metabolism. In particular, we use metabolic flux
constraint-based models to exhaustively search for artificial chemistry
pathways that can optimally perform an array of elementary metabolic functions.
Despite the simplicity of the model employed, we find that the ensuing pathways
display a surprisingly rich set of properties, including the existence of
autocatalytic cycles and hierarchical modules, the appearance of universally
preferable metabolites and reactions, and a logarithmic trend of pathway length
as a function of input/output molecule size. Some of these properties can be
derived analytically, borrowing methods previously used in cryptography. In
addition, by mapping biochemical networks onto a simplified carbon atom
reaction backbone, we find that several of the properties predicted by the
artificial chemistry model hold for real metabolic networks. These findings
suggest that optimality principles and arithmetic simplicity might lie beneath
some aspects of biochemical complexity
A Proposal for a Near Detector Experiment on the Booster Neutrino Beamline: FINeSSE: Fermilab Intense Neutrino Scattering Scintillator Experiment
219 pages219 pagesUnderstanding the quark and gluon substructure of the nucleon has been a prime goal of both nuclear and particle physics for more than thirty years and has led to much of the progress in strong interaction physics. Still the flavor dependence of the nucleon's spin is a significant fundamental question that is not understood. Experiments measuring the spin content of the nucleon have reported conflicting results on the amount of nucleon spin carried by strange quarks. Quasi-elastic neutrino scattering, observed using a novel detection technique, provides a theoretically clean measure of this quantity. The optimum neutrino beam energy needed to measure the strange spin of the nucleon is 1 GeV. This is also an ideal energy to search for neutrino oscillations at high in an astrophysically interesting region. Models of the r-process in supernovae which include high-mass sterile neutrinos may explain the abundance of neutron-rich heavy metals in the universe. These high-mass sterile neutrinos are outside the sensitivity region of any previous neutrino oscillation experiments. The Booster neutrino beamline at Fermilab provides the world's highest intensity neutrino beam in the 0.5-1.0 GeV energy range, a range ideal for both of these measurements. A small detector located upstream of the MiniBooNE detector, 100 m from the recently commissioned Booster neutrino source, could definitively measure the strange quark contribution to the nucleon spin. This detector, in conjunction with the MiniBooNE detector, could also investigate disappearance in a currently unexplored, cosmologically interesting region
Shadowing in Inelastic Scattering of Muons on Carbon, Calcium and Lead at Low XBj
Nuclear shadowing is observed in the per-nucleon cross-sections of positive
muons on carbon, calcium and lead as compared to deuterium. The data were taken
by Fermilab experiment E665 using inelastically scattered muons of mean
incident momentum 470 GeV/c. Cross-section ratios are presented in the
kinematic region 0.0001 < XBj <0.56 and 0.1 < Q**2 < 80 GeVc. The data are
consistent with no significant nu or Q**2 dependence at fixed XBj. As XBj
decreases, the size of the shadowing effect, as well as its A dependence, are
found to approach the corresponding measurements in photoproduction.Comment: 22 pages, incl. 6 figures, to be published in Z. Phys.
Observation of the decay \psip\rar\kstark
Using 14 million events collected with the BESII detector,
branching fractions of \psip\rar\kstarkpm and \kstarknn are determined to
be: \calB(\psip\rar\kstarkpm)=(2.9^{+1.3}_{-1.7}\pm0.4)\times 10^{-5} and
\calB(\psip\rar\kstarknn)=(13.3^{+2.4}_{-2.7}\pm1.9)\times 10^{-5}. The
results confirm the violation of the "12%" rule for these two decay channels
with higher precision. A large isospin violation between the charged and
neutral modes is observed.Comment: 5 pages, 3 figure
Expression of Interest for a Novel Search for CP Violation in the Neutrino Sector: DAEdALUS
Submitted to the DUSEL DirectorateSubmitted to the DUSEL DirectorateDAEdALUS, a Decay-At-rest Experiment for delta_CP studies At the Laboratory for Underground Science, provides a new approach to the search for CP violation in the neutrino sector. The design utilizes low-cost, high-power proton accelerators under development for commercial uses. These provide neutrino beams with energy up to 52 MeV from pion and muon decay-at-rest. The experiment searches for aninu_mu to antinu_e at short baselines corresponding to the atmospheric Delta m^2 region. The antinu_e will be detected, via inverse beta decay, in the 300 kton fiducial-volume Gd-doped water Cherenkov neutrino detector proposed for the Deep Underground Science and Engineering Laboratory (DUSEL). DAEdALUS opens new opportunities for DUSEL. It provides a high-statistics, low-background alternative for CP violation searches which matches the capability of the conventional long-baseline neutrino experiment, LBNE. Because of the complementary designs, when DAEdALUS antineutrino data are combined with LBNE neutrino data, the sensitivity of the CP-violation search improves beyond any present proposals, including the proposal for Project X. Also, the availability of an on-site neutrino beam opens opportunities for additional physics, both for the presently planned DUSEL detectors and for new experiments at a future 300 ft campus
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