3,422 research outputs found
Perceptual Strategies and Neuronal Underpinnings underlying Pattern Recognition through Visual and Tactile Sensory Modalities in Rats
The aim of my PhD project was to investigate multisensory perception and multimodal recognition abilities in the rat, to better understand the underlying perceptual strategies and neuronal mechanisms.
I have chosen to carry out this project on the laboratory rat, for two reasons. First, the rat is a flexible and highly accessible experimental model, where it is possible to combine state-of-the-art neurophysiological approaches (such as multi-electrode neuronal recordings) with behavioral investigation of perception and (more in general) cognition. Second, extensive research concerning multimodal integration has already been conducted in this species, both at the neurophysiological and behavioral level.
My thesis work has been organized in two projects: a psychophysical assessment of object categorization abilities in rats, and a neurophysiological study of neuronal tuning in the primary visual cortex of anaesthetized rats. In both experiments, unisensory (visual and tactile) and multisensory (visuo-tactile) stimulation has been used for training and testing, depending on the task.
The first project has required development of a new experimental rig for the study of object categorization in rat, using solid objects, so as to be able to assess their recognition abilities under different modalities: vision, touch and both together.
The second project involved an electrophysiological study of rat primary visual cortex, during visual, tactile and visuo-tactile stimulation, with the aim of understanding whether any interaction between these modalities exists, in an area that is mainly deputed to one of them.
The results of both of the studies are still preliminary, but they already offer some interesting insights on the defining features of these abilities
Key elements of global inflation
Against the background of large fluctuations in world commodity prices and global growth, combined with ongoing structural changes relating to globalization, this paper examines some of the key factors affecting global inflation. The paper empirically investigates various relative price and structural impacts on global inflation by: estimating a GVAR to examine how oil price shocks feed through to core and headline inflation; calculating the impact of increased imports from low-cost countries on manufacturing import prices; estimating Phillips curves in order to shed light on whether the inflationary process in the OECD countries has changed over time, particularly with respect to the roles of import prices, unit labour costs and the output gap. Overall, the paper finds that there seem to be various significant pressures on global trade prices and labour markets associated with structural factors possibly partly due to globalisation which, in addition to monetary policy, seem to be behind some of the changes in the inflation process over the period examined in this paper.Phillips Curve, inflation, output gap, import prices, unit labour costs, globalisation, monetary policy.
Transformation-tolerant object recognition in rats revealed by visual priming
Successful use of rodents as models for studying object vision crucially depends on the ability of their visual system to construct representations of visual objects that tolerate (i.e., remain relatively unchanged with respect to) the tremendous changes in object appearance produced, for instance, by size and viewpoint variation. Whether this is the case is still controversial, despite some recent demonstration of transformation-tolerant object recognition in rats. In fact, it remains unknown to what extent such a tolerant recognition has a spontaneous, perceptual basis, or, alternatively, mainly reflects learning of arbitrary associative relations among trained object appearances. In this study, we addressed this question by training rats to categorize a continuum of morph objects resulting from blending two object prototypes. The resulting psychometric curve (reporting the proportion of responses to one prototype along the morph line) served as a reference when, in a second phase of the experiment, either prototype was briefly presented as a prime, immediately before a test morph object. The resulting shift of the psychometric curve showed that recognition became biased toward the identity of the prime. Critically, this bias was observed also when the primes were transformed along a variety of dimensions (i.e., size, position, viewpoint, and their combination) that the animals had never experienced before. These results indicate that rats spontaneously perceive different views/appearances of an object as similar (i.e., as instances of the same object) and argue for the existence of neuronal substrates underlying formation of transformation-tolerant object representations in rats
Diagrammatic Polyhedral Algebra
We extend the theory of Interacting Hopf algebras with an order primitive, and give a sound and complete axiomatisation of the prop of polyhedral cones. Next, we axiomatise an affine extension and prove soundness and completeness for the prop of polyhedra
A method for obtaining the I-V curve of photovoltaic arrays from module voltages and its applications for MPP tracking
For the purpose of control and monitoring of a Photovoltaic (PV) system its current-voltage (I-V) charac-
teristic curve is traced. Usually such a test involves the interruption of the normal operation of the PV
systems. In this paper a method for tracing the I-V curve from on-site measurements is proposed.
During the measurement of the characteristic curve the normal operation of the PV system is not inter-
rupted. The subjects of tracing the characteristic curve and Maximum Power Point Tracking (MPPT) of PV
arrays are generally dealt with separately but the proposed method performs the measurement of the
characteristic curve quickly and so it can also be utilized for MPPT purposes. Simulations and experi-
ments have been conducted to confirm the operation of the proposed metho
Pregnancy in fanconi anaemia with bone marrow failure: A case report and review of the literature
BACKGROUND: Fanconi anaemia is a rare inherited disease characterized by congenital abnormalities, progressive bone marrow failure and predisposition to malignancy. Successful pregnancies in transplanted patients have been reported. In this paper we will describe the pregnancy of a patient with Fanconi anaemia without transplantation. CASE PRESENTATION: A 34-year-old nulliparous woman with Fanconi anaemia was referred to our institution. Pregnancy was complicated by progressive pancytopenia and two severe infections. C-section was performed at 36Â weeks. Both infant and mother are well. CONCLUSION: Successful pregnancy in a Fanconi anaemia patient with bone marrow failure is possible. The mode of delivery in patients with bone marrow failure should be determined by obstetric indications. The case highlights the safe outcome of the pregnancy with strict clinical and laboratory control by a multidisciplinary team
Wearable sensors for humanârobot walking together
Thanks to recent technological improvements that enable novel applications beyond the industrial context, there is growing interest in the use of robots in everyday life situations. To improve the acceptability of personal service robots, they should seamlessly interact with the users, understand their social signals and cues and respond appropriately. In this context, a few proposals were presented to make robots and humans navigate together naturally without explicit user control, but no final solution has been achieved yet. To make an advance toward this end, this paper proposes the use of wearable Inertial Measurement Units to improve the interaction between human and robot while walking together without physical links and with no restriction on the relative position between the human and the robot. We built a prototype system, experimented with 19 human participants in two different tasks, to provide real-time evaluation of gait parameters for a mobile robot moving together with a human, and studied the feasibility and the perceived usability by the participants. The results show the feasibility of the system, which obtained positive feedback from the users, giving valuable information for the development of a natural interaction system where the robot perceives human movements by means of wearable sensors
Towards the Complete Self-Sufficiency of a nZEBs microgrid by Photovoltaic Generators and Heat Pumps: Methods and Applications
The present paper proposes a multidisciplinary procedure to correctly design a microgrid of all-electric nZEBs (nearly Zero Energy Buildings) from both electrical and thermal points of view. The procedure is suitable for new buildings supplied by local renewables, without the use of fossil fuel and with zero emissions. First, the thermal demand of each single nZEB is assessed, as a function of the installation site, building layout and physics, and material composing the envelope. Thanks to heat pumps, the thermal demand is transformed in electric load. Thus, the total electric consumption profiles, which include user's appliances and heating/cooling, are studied and compared with Photovoltaic (PV) generation supported by electrochemical storages. Both PV and batteries are simulated thanks to appropriate models. Regarding the PV production assessment, the present work proposes an improvement with respect to the use of traditional models, and it is based on experimental results on PV generators of recent production. The design methodology is applied to a real case of âenergy communityâ composed of three nZEB units, that will be built in the campus of Politecnico di Torino, available to students and staff. The three units share PV production and storage capacity to reach the complete grid-independence
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