463 research outputs found
Correlation Plenoptic Imaging With Entangled Photons
Plenoptic imaging is a novel optical technique for three-dimensional imaging
in a single shot. It is enabled by the simultaneous measurement of both the
location and the propagation direction of light in a given scene. In the
standard approach, the maximum spatial and angular resolutions are inversely
proportional, and so are the resolution and the maximum achievable depth of
focus of the 3D image. We have recently proposed a method to overcome such
fundamental limits by combining plenoptic imaging with an intriguing
correlation remote-imaging technique: ghost imaging. Here, we theoretically
demonstrate that correlation plenoptic imaging can be effectively achieved by
exploiting the position-momentum entanglement characterizing spontaneous
parametric down-conversion (SPDC) photon pairs. As a proof-of-principle
demonstration, we shall show that correlation plenoptic imaging with entangled
photons may enable the refocusing of an out-of-focus image at the same depth of
focus of a standard plenoptic device, but without sacrificing
diffraction-limited image resolution.Comment: 12 pages, 5 figure
Diffraction-limited plenoptic imaging with correlated light
Traditional optical imaging faces an unavoidable trade-off between resolution
and depth of field (DOF). To increase resolution, high numerical apertures (NA)
are needed, but the associated large angular uncertainty results in a limited
range of depths that can be put in sharp focus. Plenoptic imaging was
introduced a few years ago to remedy this trade off. To this aim, plenoptic
imaging reconstructs the path of light rays from the lens to the sensor.
However, the improvement offered by standard plenoptic imaging is practical and
not fundamental: the increased DOF leads to a proportional reduction of the
resolution well above the diffraction limit imposed by the lens NA. In this
paper, we demonstrate that correlation measurements enable pushing plenoptic
imaging to its fundamental limits of both resolution and DOF. Namely, we
demonstrate to maintain the imaging resolution at the diffraction limit while
increasing the depth of field by a factor of 7. Our results represent the
theoretical and experimental basis for the effective development of the
promising applications of plenoptic imaging.Comment: 10 pages, 10 figure
High-density magnetomyography is superior over surface electromyography for the decomposition of motor units: a simulation study
Studying motor units (MUs) is essential for understanding motor control, the
detection of neuromuscular disorders and the control of human-machine
interfaces. Individual motor unit firings are currently identified in vivo by
decomposing electromyographic (EMG) signals. Due to our body's electric
properties, individual motor units can only be separated to a limited extent
with surface EMG. Unlike electrical signals, magnetic fields pass through
biological tissues without distortion. This physical property and emerging
technology of quantum sensors make magnetomyography (MMG) a highly promising
methodology. However, the full potential of MMG to study neuromuscular
physiology has not yet been explored. In this work, we perform in silico trials
that combine a biophysical model of EMG and MMG with state-of-the-art
algorithms for the decomposition of motor units. This allows the prediction of
an upper-bound for the motor unit decomposition accuracy. It is shown that
non-invasive MMG is superior over surface EMG for the robust identification of
the discharge patterns of individual motor units. Decomposing MMG instead of
EMG increased the number of identifiable motor units by 71%. Notably, MMG
exhibits a less pronounced bias to detect superficial motor units. The
presented simulations provide insights into methods to study the neuromuscular
system non-invasively and in vivo that would not be easily feasible by other
means. Hence, this study provides guidance for the development of novel
biomedical technologies
Correlation Plenoptic Imaging between Arbitrary Planes
We propose a novel method to perform plenoptic imaging at the diffraction
limit by measuring second-order correlations of light between two reference
planes, arbitrarily chosen, within the tridimensional scene of interest. We
show that for both chaotic light and entangled-photon illumination, the
protocol enables to change the focused planes, in post-processing, and to
achieve an unprecedented combination of image resolution and depth of field. In
particular, the depth of field results larger by a factor 3 with respect to
previous correlation plenoptic imaging protocols, and by an order of magnitude
with respect to standard imaging, while the resolution is kept at the
diffraction limit. The results lead the way towards the development of compact
designs for correlation plenoptic imaging devices based on chaotic light, as
well as high-SNR plenoptic imaging devices based on entangled photon
illumination, thus contributing to make correlation plenoptic imaging
effectively competitive with commercial plenoptic devices.Comment: 12 pages, 6 figure
Correlated-photon imaging at 10 volumetric images per second
The correlation properties of light provide an outstanding tool to overcome
the limitations of traditional imaging techniques. A relevant case is
represented by correlation plenoptic imaging (CPI), a quantum-inspired
volumetric imaging protocol employing spatio-temporally correlated photons from
either entangled or chaotic sources to address the main limitations of
conventional light-field imaging, namely, the poor spatial resolution and the
reduced change of perspective for 3D imaging. However, the application
potential of high-resolution imaging modalities relying on photon correlations
is limited, in practice, by the need to collect a large number of frames. This
creates a gap, unacceptable for many relevant tasks, between the time
performance of correlated-light imaging and that of traditional imaging
methods. In this article, we address this issue by exploiting the photon number
correlations intrinsic in chaotic light, combined with a cutting-edge ultrafast
sensor made of a large array of single-photon avalanche diodes (SPADs). This
combination of source and sensor is embedded within a novel single-lens CPI
scheme enabling to acquire 10 volumetric images per second. Our results place
correlated-photon imaging at a competitive edge and prove its potential in
practical applications.Comment: 13 pages, 6 figure
Nonclassical noise features in a correlation plenoptic imaging setup
Sub-shot-noise imaging and correlation plenoptic imaging are two quantum imaging techniques that enable to overcome different problems of classical imaging systems. Combining the two techniques is not trivial, since the former is based on the detection of identical corresponding modes to subtract noise, while the latter requires the detection of different modes to perform directional reconstruction. In this paper, we experimentally show the possibility to obtain a noise-reduction factor smaller than one, a necessary condition to perform sub-shot-noise imaging, in a setup that can be adapted to correlation plenoptic imaging
Theatre is a valid add-on therapeutic intervention for emotional rehabilitation of parkinson's disease patients
Conventional medical treatments of Parkinson's disease (PD) are effective on motor disturbances but may have little impact on nonmotor symptoms, especially psychiatric ones. Thus, even when motor symptomatology improves, patients might experience deterioration in their quality of life. We have shown that 3 years of active theatre is a valid complementary intervention for PD as it significantly improves the well-being of patients in comparison to patients undergoing conventional physiotherapy. Our aim was to replicate these findings while improving the efficacy of the treatment. We ran a single-blinded pilot study lasting 15 months on 24 subjects with moderate idiopathic PD. 12 were assigned to a theatre program in which patients underwent "emotional" training. The other 12 underwent group physiotherapy. Patients were evaluated at the beginning and at the end of their treatments, using a battery of eight clinical and five neuropsychological scales. We found that the emotional theatre training improved the emotional well-being of patients, whereas physiotherapy did not. Interestingly, neither of the groups showed improvements in either motor symptoms or cognitive abilities tested by the neuropsychological battery. We confirmed that theatre therapy might be helpful in improving emotional well-being in PD
LEGU-MED: Developing biodiversity-based agriculture with legume cropping systems in the mediterranean basin
Environmental degradation and the decrease of ecosystem service provision are currently of major concern, with current agricultural systems being a major driver. To meet our future environmental and sustainability targets a transformation of the agro-food systems and current agricultural value chain are crucial. One approach to redesign farming systems is the concept of biodiversity-based agriculture (BBA) which relies on sustainable diversification of biological components and their natural interactions in farming systems to maximize fertility, productivity, and resilience to external perturbations. Despite minimizing anthropogenic inputs, BBA is not yet able to meet all beneficial environmental objectives. BBA applied in the Mediterranean basin requires urgent innovation in approaches, methodologies, and models for small-holder traditional farming systems to ensure a stable provision of ecosystem services and better resilience to environmental stresses linked to climate change. Legumes are the backbone of the Mediterranean agro-ecosystems from ancient times, but their unique and wide biodiversity was not sufficiently valorized, especially by North-African countries. Here, we present LEGU-MED, a three-year international project funded by PRIMA initiative 2019. An international consortium was established involving five universities, 5 research institutes, and one private company from 8 countries: Italy, Germany, Spain, Algeria, Tunisia, Turkey, Lebanon, and Croatia. The main objective of this project is to put forward an international and well-integrated plan to valorize the legume agrobiodiversity of the Mediterranean in biodiversity-based farming systems and consequently enhance agro-ecosystem functions and services in the Mediterranean basin. The successful completion of LEGU-MED will have the following impacts on Mediterranean legume-based farming systems: (1) improve water use efficiency, (2) reduce the use of anthropogenic inputs through the maintenance of soil fertility, (3) enhance pollination and improve ecological connectivity with flora and fauna, (4) protect close-by wildland ecosystems, (5) enhance other ecosystem services (e.g., pest, disease, and weed suppression), and (6) provide healthier and safer protein-rich food
The Effect of Manual Therapy Plus Exercise in Patients with Lateral Ankle Sprains: A Critically Appraised Topic with a Meta-Analysis
A high percentage of patients with lateral ankle sprains report poor outcomes and persistent neuromuscular impairment leading to chronic ankle instability and re-injury. Several interventions have been proposed and investigated, but the evidence on manual therapy combined with therapeutic exercise for pain reduction and functional improvement is still uncertain. The purpose was to study the effectiveness of adding manual therapy to therapeutic exercise in patients with lateral ankle sprains through a critically appraised topic. The literature search was performed in PubMed, PEDro, EMBASE and CINAHL databases, and only randomized clinical trials were included according to following criteria: (1) subjects with acute episodes of lateral ankle sprains, (2) administered manual therapy plus therapeutic exercise, (3) comparisons with therapeutic exercise alone and (4) reported outcomes for pain and function. Three randomized clinical trials (for a total of 180 patients) were included in the research. Meta-analyses revealed that manual therapy plus exercise was more effective than only exercises in improving dorsal (MD = 8.79, 95% CI: 6.81, 10.77) and plantar flexion (MD = 8.85, 95% CI 7.07, 10.63), lower limb function (MD = 1.20, 95% CI 0.63, 1.77) and pain (MD = -1.23; 95% IC -1.73, -0.72). Manual therapy can be used with therapeutic exercise to improve clinical outcome in patients with lateral ankle sprains
Automated solid-state NMR resonance assignment of protein microcrystals and amyloids
Solid-state NMR is an emerging structure determination technique for crystalline and non-crystalline protein assemblies, e.g., amyloids. Resonance assignment constitutes the first and often very time-consuming step to a structure. We present ssFLYA, a generally applicable algorithm for automatic assignment of protein solid-state NMR spectra. Application to microcrystals of ubiquitin and the Ure2 prion C-terminal domain, as well as amyloids of HET-s(218-289) and α-synuclein yielded 88-97% correctness for the backbone and side-chain assignments that are classified as self-consistent by the algorithm, and 77-90% correctness if also assignments classified as tentative by the algorithm are include
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