Singular topologies in the Boulatov model

Through the question of singular topologies in the Boulatov model, we illustrate and summarize some of the recent advances in Group Field Theory.Comment: 4 pages; proceedings of Loops'11 (May 2011, Madrid); v2: minor modifications matching published versio

Melonic phase transition in group field theory

Group field theories have recently been shown to admit a 1/N expansion dominated by so-called `melonic graphs', dual to triangulated spheres. In this note, we deepen the analysis of this melonic sector. We obtain a combinatorial formula for the melonic amplitudes in terms of a graph polynomial related to a higher dimensional generalization of the Kirchhoff tree-matrix theorem. Simple bounds on these amplitudes show the existence of a phase transition driven by melonic interaction processes. We restrict our study to the Boulatov-Ooguri models, which describe topological BF theories and are the basis for the construction of four dimensional models of quantum gravity.Comment: 8 pages, 4 figures; to appear in Letters in Mathematical Physic

Use of beneficial bacteria Azospirillum brasilense Sp245 on grapevine rootstocks grafted with 'Sangiovese'

Azospirillum brasilense Sp245, a well-known PGPR (plant growth-promoting rhizobacteria), was examined in order to evaluate the effects on nursery propagation. In addition the aim was to test the ability of the inoculated bacterium to improve the rooting parameters of some rootstocks that do not easily root through conventional techniques. Nine rootstocks were tested in a conventional nursery, while two rootstocks were tested in organic nursery: V. berlandieri × V. riparia 420A, 161-49, 157-11, SO4; V. berlandieri × V. rupestris 140Ru, 775P, 1103P; V. riparia × V. rupestris 101-14, 3309C. The quality of the root system was improved in terms of the number of roots, root architecture and the total biomass of vines produced in the organic nursery, while in the conventional nursery the results depended on the rootstock. The results suggest that further study is needed for a better comprehension of the mode of action and to establish how PGPR could be used for the sustainable production of grapevine plants

Control of multifunctional prosthetic hands by processing the electromyographic signal

The human hand is a complex system, with a large number of degrees of freedom (DoFs), sensors embedded in its structure, actuators and tendons, and a complex hierarchical control. Despite this complexity, the efforts required to the user to carry out the different movements is quite small (albeit after an appropriate and lengthy training). On the contrary, prosthetic hands are just a pale replication of the natural hand, with significantly reduced grasping capabilities and no sensory information delivered back to the user. Several attempts have been carried out to develop multifunctional prosthetic devices controlled by electromyographic (EMG) signals (myoelectric hands), harness (kinematic hands), dimensional changes in residual muscles, and so forth, but none of these methods permits the "natural" control of more than two DoFs. This article presents a review of the traditional methods used to control artificial hands by means of EMG signal, in both the clinical and research contexts, and introduces what could be the future developments in the control strategy of these devices

Experimental Analysis of RSSI-based Indoor Location Systems with WL Circularly Polarized Antennas

Circularly polarized antennas are used in 2.4 GHz ZigBee radio modules to evaluate performance improvement of RSSI (Received Signal Strength Indicator) based location techniques, with respect to conventional linearly polarized antennas. Experimental RSSI measurements in an indoor environment clearly show that multipath fading is significantly reduced when CP antennas are used; this determines a more reliable estimation of the field amplitude decay law as a function of the distance of the mobile node from the fixed access point, and then a higher location accuracy. At the best of authors' knowledge, it is the first time that the circular polarization features are applied to RSSI-based radio location techniques

Preliminary evaluation of SensHand V1 in assessing motor skills performance in Parkinson Disease

Nowadays, the increasing old population 65+ as well as the pace imposed by work activities lead to a high number of people that have particular injuries for limbs. In addition to persistent or temporary disabilities related to accidental injuries we must take into account that part of the population suffers from motor deficits of the hands due to stroke or diseases of various clinical nature. The most recurrent technological solutions to measure the rehabilitation or skill motor performance of the hand are glove-based devices, able to faithfully capture the movements of the hand and fingers. This paper presents a system for hand motion analysis based on 9-axis complete inertial modules and dedicated microcontroller which are fixed on fingers and forearm. The technological solution presented is able to track the patients' hand motions in real-time and then to send data through wireless communication reducing the clutter and the disadvantages of a glove equipped with sensors through a different technological structure. The device proposed has been tested in the study of Parkinson's disease

Improving domiciliary robotic services by integrating the ASTRO Robot in an AmI Infrastructure

This work describes the ECHORD Experiment ASTROMOBILE, a project aimed to design, develop and test a system for favourable independent living, improved quality of life and efficiency of care for senior citizens in domestic environments. The system, composed of a mobile robotic platform (called ASTRO) and an Ambient Intelligent Infrastructure that actively cooperated between them and with the end-user, was designed and implemented with a user-centred design approach, involving different stakeholders. The system was designed to deliver services to users, like drug delivery, stand support, reminding, info-entertainment. The design took advantages of the integration of robotic platforms with smart environments, to provide to users higher quality and localization based services. Senior end-users were involved in the experimentation of the system in the DomoCasa Living Lab and feedbacks were gathered for the technology assessment. Particularly, this paper demonstrates the general feasibility of the ASTROMOBILE system and thanks to users feedbacks its acceptability and usability

Upper Limb Spasticity Reduction Following Active Training: A Robot-Mediated Study In Patients With Chronic Hemiparesis

sion of the arm. A 3-month follow-up was performed. Results: Statistically significant improvements were found in both groups after treatment. Some differences were found in elbow motor improvement between the 2 groups. Conclusion: Comparison between groups confirms that active movement training does not result in increased hypertonia, but results in spasticity reduction in antagonist muscles by activating the reciprocal inhibition mechanism. Furthermore, robot-mediated therapy contributes to a decrease in motor impairment of the upper limbs in subjects with chronic hemiparesis, resulting in a reduction in shoulder pain