430 research outputs found
The Thirring quantum cellular automaton
We analytically diagonalize a discrete-time on-site interacting fermionic
cellular automaton in the two-particle sector. Important features of the
solutions sensibly differ from those of analogous Hamiltonian models. In
particular, we found a wider variety of scattering processes, we have bound
states for every value of the total momentum, and there exist bound states also
in the free case, where the coupling constant is null.Comment: 4 pages+references, Revtex style, 2 figures, supplemental material
included as appendi
Optimal quantum tomography for states, measurements, and transformations
We present the first complete optimization of quantum tomography, for states,
POVMs, and various classes of transformations, for arbitrary prior ensemble and
arbitrary representation, giving corresponding feasible experimental schemes.Comment: 4 pages, 1 figur
Defensive peripersonal space is modified by a learnt protective posture
The Hand Blink Reflex (HBR) is a subcortical defensive response, elicited by the electrical stimulation of the median nerve. HBR increases when the stimulated hand is inside the defensive peripersonalspace (DPPS) of the face. However, the presence of a screen protecting the face could reduce the amplitude of this response. This work aimed to investigate whether the learning of a posture intended to protect the head could modulate the HBR responses. Boxing athletes learn a defensive posture consisting of blocking with arms opponent\u2019s blow towards the face. Two groups were recruited: 13 boxers and 13 people na\uefve to boxing. HBR response was recorded and elicited in three hand positions depending on the distance from the face. A suppression of HBR enhancement in the static position close to the face was observed in boxer group, contrary to the control group. Also, the higher years of practice in boxing, the higher suppression occurred. However, this suppression was not observed when boxers were asked to move the hand up-to/down-from the face. These findings might suggest that the sensorimotor experience related to a previously learnt protective posture can modify the HBR and thus shape the dimension of the DPPS
Phase-Based Binocular Perception of Motion in Depth: Cortical-Like Operators and Analog VLSI Architectures
We present a cortical-like strategy to obtain reliable estimates of the motions of objects in a scene toward/away from the observer (motion in depth), from local measurements of binocular parameters derived from direct comparison of the results of monocular spatiotemporal filtering operations performed on stereo image pairs. This approach is suitable for a hardware implementation, in which such parameters can be gained via a feedforward computation (i.e., collection, comparison, and punctual operations) on the outputs of the nodes of recurrent VLSI lattice networks, performing local computations. These networks act as efficient computational structures for embedded analog filtering operations in smart vision sensors. Extensive simulations on both synthetic and real-world image sequences prove the validity of the approach that allows to gain high-level information about the 3D structure of the scene, directly from sensorial data, without resorting to explicit scene reconstruction
Optimal quantum learning of a unitary transformation
We address the problem of learning an unknown unitary transformation from a
finite number of examples. The problem consists in finding the learning machine
that optimally emulates the examples, thus reproducing the unknown unitary
maximum fidelity. Learning a unitary is equivalent to storing it in the state
of a quantum memory (the memory of the learning machine), and subsequently
retrieving it. We prove that, whenever the unknown unitary is drawn from a
group, the optimal strategy consists in a parallel call of the available uses
followed by a "measure-and-rotate" retrieving. Differing from the case of
quantum cloning, where the incoherent "measure-and-prepare" strategies are
typically suboptimal, in the case of learning the "measure-and-rotate" strategy
is optimal even when the learning machine is asked to reproduce a single copy
of the unknown unitary. We finally address the problem of the optimal inversion
of an unknown unitary evolution, showing also in this case the optimality of
the "measure-and-rotate" strategies and applying our result to the optimal
approximate realignment of reference frames for quantum communication.Comment: 7 pages, 1 figure, published versio
Computer-assisted technique for airborne dust sampling data representativeness and worker's exposure assessment - CAT-ReADS
Nowadays, occupational exposure to airborne dust is still one of the most concerning problems our society should face, since both airborne dust is a common pollutant in almost all the NACE sectors activities, and the occupational exposure quantification is critical. One of the possible causes can be identified in determining the real conditions of dust pollution in the workplaces, attributable to the delicacy of the various phases of acquisition of the measures, and on the variability of operations carried out by workers, affecting the pollutant emission rates. A research project in progress discusses the causes of uncertainty attributable to laboratory and sampling activities, and to the identification of the most appropriate techniques of the resultsâ representativeness assessment. A recent result is the development of an original Computer-Assisted Technique for Airborne Dust Sampling data representativeness and worker's exposure assessment - CAT-ReADS, MS-Excelïą Vbasicïą developed - it supports the companies and external audit technicians, from the setting of the surveys and the laboratory activities to the verification, in a rigorous statistical approach, of compliance/noncompliance of the field measurement results vs the limit values. The resulting workplaces pollution and workersâ exposure assessment are free from subjective simplifications: CAT-ReADS includes various sections of guided selection and data analysis, covering Instruments and their calibration, Recording of environmental parameters and activities carried out by the workers during the samplings, Calculation of concentrations, Calculation of expanded uncertainty, Statistical tests for estimating the probability of exceeding the limit value, both referring â as is common practice- to the mean value, and, in a more cautionary way, to the upper uncertainty values (assuming a confidence level of 95%). The paper provides some examples of the implementation of CAT-ReADS in different production scenarios, and an in-depth discussion of the results
06N-P63\u3b1 and TA-P63\u3b1 exhibit intrinsic differences in transactivation specificities that depend on distinct features of DNA target sites.
TP63 is a member of the TP53 gene family that encodes for up to ten different TA
and 06N isoforms through alternative promoter usage and alternative splicing.
Besides being a master regulator of gene expression for squamous epithelial
proliferation, differentiation and maintenance, P63, through differential
expression of its isoforms, plays important roles in tumorigenesis. All P63
isoforms share an immunoglobulin-like folded DNA binding domain responsible for
binding to sequence-specific response elements (REs), whose overall consensus
sequence is similar to that of the canonical p53 RE. Using a defined assay in
yeast, where P63 isoforms and RE sequences are the only variables, and gene
expression assays in human cell lines, we demonstrated that human TA- and 06N-P63\u3b1
proteins exhibited differences in transactivation specificity not observed with
the corresponding P73 or P53 protein isoforms. These differences 1) were
dependent on specific features of the RE sequence, 2) could be related to
intrinsic differences in their oligomeric state and cooperative DNA binding, and
3) appeared to be conserved in evolution. Since genotoxic stress can change
relative ratio of TA- and 06N-P63\u3b1 protein levels, the different transactivation
specificity of each P63 isoform could potentially influence cellular responses to
specific stresses
Action observation combined with conventional training improves the rugby lineout throwing performance: A pilot study
Combining action observation (AO) and physical practice contributes to motor skill learning, and a number of studies pointed out the beneficial role of AO training in improving the motor performance and the athletes' movement kinematics. The aim of this study was to investigate if AO combined with immediate conventional training was able to improve motor performance and kinematic parameters of a complex motor skill such as the lineout throw, a gesture that represents a key aspect of rugby, that is unique to this sport. Twenty elite rugby players were divided into 2 groups. The AO group watched a 5-min video-clip of an expert model performing the lineout throw towards a target at 7 m distance and, immediately after the AO, this group executed the conventional training, consisting of 6 repetitions x 5 blocks of throws. The CONTROL group performed only the conventional lineout training. Intervention period lasted 4 weeks, 3 sessions/week. The AO group showed significant improvements in throwing accuracy (i.e. number of throws hitting the target), whilst no significant changes were observed in the CONTROL group. As concerns kinematic parameters, hooker's arm mean velocity significantly increased in both groups, but the increase was higher in AO group compared to CONTROL group. Ball velocity significantly increased only in the AO group, whereas ball angle release and ball spinning significantly decreased in both groups, with no differences between groups. Finally, no significant changes in knee and elbow angles were observed. Our results showed that the combination of AO and conventional training was more effective than a conventional training alone in improving the performance of elite rugby players, in executing a complex motor skill, such as the lineout. This combined training led to significant improvements in throwing accuracy and in hooker's and ball's kinematic parameters. Since AO can be easily implemented in combination with conventional training, the results of this study can encourage coaches in designing specific lineout training programs, which include AO cognitive training
Identification of <i>Salvia haenkei</i> as gerosuppressant agent by using an integrated senescence-screening assay.
Cellular senescence is a stable cell cycle arrest that is the causative process of aging. The PI3K/AKT/mTOR pathway is implicated in the control of cellular senescence and inhibitors of this pathway have been successfully used for life span prolongation experiments in mammals. PTEN is the major regulator of the PI3K/AKT/mTOR pathway and loss of PTEN promotes a senescence response termed PICS. Here we report a novel-screening assay, for the identification of compounds that block different types of senescence response. By testing a library of more than 3000 natural and chemical compounds in PTEN deficient cells we have found that an extract from <i>Salvia haenkei</i> (SH), a native plant of Bolivia is a potent inhibitor of PICS. SH also decreases replicative and UV-mediated senescence in human primary fibroblasts and in a model of <i>in vitro</i> reconstructed human epidermis. Mechanistically, SH treatment affects senescence driven by UV by interfering with IL1-α signalling. Pre-clinical and clinical testing of this extract by performing toxicity and irritability evaluation <i>in vitro</i> also demonstrate the safety of SH extract for clinical use as anti-aging skin treatment
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