1,072 research outputs found
High-energy elementary amplitudes from quenched and full QCD
Making use of the Stochastic Vacuum Model and the gluon gauge-invariant
two-point correlation function, determined by numerical simulation on the
lattice in both quenched approximation and full QCD, we calculate the
elementary (quark-quark) scattering amplitudes in the momentum transfer space
and at asymptotic energies. Our main conclusions are the following: (1) the
amplitudes decrease monotonically as the momentum transfer increases; (2) the
decreasing is faster when going from quenched approximation to full QCD (with
decreasing quark masses) and this effect is associated with the increase of the
correlation lengths; (3) dynamical fermions generate two components in the
amplitude at small momentum transfer and the transition between them occurs at
momentum transfer near 1 GeV. We also obtain analytical parametrizations
for the elementary amplitudes, that are suitable for phenomenological uses, and
discuss the effects of extrapolations from the physical regions investigated in
the lattice.Comment: 6 pages, 4 figures, aps-revtex4, to be published in Physics Letters
Pauli Tomography: complete characterization of a single qubit device
The marriage of Quantum Physics and Information Technology, originally
motivated by the need for miniaturization, has recently opened the way to the
realization of radically new information-processing devices, with the
possibility of guaranteed secure cryptographic communications, and tremendous
speedups of some complex computational tasks. Among the many problems posed by
the new information technology there is the need of characterizing the new
quantum devices, making a complete identification and characterization of their
functioning. As we will see, quantum mechanics provides us with a powerful tool
to achieve the task easily and efficiently: this tools is the so called quantum
entanglement, the basis of the quantum parallelism of the future computers. We
present here the first full experimental quantum characterization of a
single-qubit device. The new method, we may refer to as ''quantum
radiography'', uses a Pauli Quantum Tomography at the output of the device, and
needs only a single entangled state at the input, which works on the test
channel as all possible input states in quantum parallel. The method can be
easily extended to any n-qubits device
Classification and mapping of the woody vegetation of Gonarezhou National Park, Zimbabwe
Within the framework of the Great Limpopo Transfrontier Conservation Area (GLTFCA), the purpose of this study was to produce a classification of the woody vegetation of the Gonarezhou National Park, Zimbabwe, and a map of its potential distribution. Cover-abundance data of woody species were collected in 330 georeferenced relevés across the Park. These data were used to produce two matrices: the first one using the cover-abundance values as collected in five height layers and the second one based on merging the layers into a single cover value for each species. Automatic classifications were produced for both matrices to determine the optimal number of vegetation types. The two classification approaches both produced 14 types belonging to three macro-groups: mopane, miombo and alluvial woodlands. The results of the two classifications were compared looking at the constant, dominant and diagnostic species of each type. The classification based on separate layers was considered more effective and retained. A high-resolution map of the potential distribution of vegetation types for the whole study area was produced using Random Forest. In the model, the relationship between bioclimatic and topographic variables, known to be correlated to vegetation types, and the classified relevés was used. Identified vegetation types were compared with those of other national parks within the GLTFCA, and an evaluation of the main threats and pressures was conducted. Conservation implications: Vegetation classification and mapping are useful tools for multiple purposes including: surveying and monitoring plant and animal populations, communities and their habitats, and development of management and conservation strategies. Filling the knowledge gap for the Gonarezhou National Park provides a basis for standardised and homogeneous vegetation classification and mapping for the entire Great Limpopo Transfrontier Conservation Area
La Pain Neuroscience Education nel trattamento della lombalgia cronica aspecifica: revisione sistematica della letteratura
Background: La lombalgia cronica aspecifica ha un impatto socioeconomico molto importante in termini di ospedalizzazione, farmaci, test diagnostici e consultazioni specialistiche. Colpisce inoltre anche la sfera emozionale, sociale e lavorativa delle persone affette dalla sintomatologia. Le linee guida dell’American College of Physician (2017) consigliano un iniziale approccio multidisicplinare non farmacologico che comprenda anche terapia cognitivo-comportamentale e fisioterapia. La Pain Neuroscience Education è un programma di educazione cognitivo-comportamentale che, aumentando la conoscenza dei meccanismi neurofisiologici del dolore, mira a diminuire l’intensità dei sintomi e produrre nelle persone cambiamenti comportamentali.
Obiettivi: valutare l’efficacia della Pain Neuroscience Education in termini di miglioramento dei sintomi dolore, disabilità percepita, kinesiofobia e catastrofizzazione del dolore, nel trattamento di persone adulte affette da lombalgia cronica aspecifica.
Disegno di Studio: revisione sistematica strutturata seguendo il PRISMA Statement.
Fonti dei Dati: PUBMED, PEDro e CINAHL Complete (inclusi i database EBSChost: PsycARTICLES, Psychology and Behavioral Sciences Collection e PsycINFO).
Criteri di Eleggibilità : RCT con partecipanti di età adulta (≥ 18 anni) affetti da lombalgia cronica (≥ 12 settimane) aspecifica. Sono inclusi studi che prevedano intervento di Pain Neuroscience Education, o equivalenti, come unica terapia o in associazione ad altre tecniche di trattamento.
Risultati: 5 studi hanno rispettato i criteri di eleggibilità . Hanno ottenuto tutti un punteggio ≥ 6 nella valutazione con PEDro Scale, perciò possono essere considerati di alta qualità metodologica.
Conclusioni: La Pain Neuroscience Education si è dimostrata utile nel ridurre dolore, disabilità percepita, kinesiofobia e catastrofizzazione del dolore a breve e medio termine in soggetti adulti affetti da lombalgia cronica aspecifica
Exploiting quantum parallelism of entanglement for a complete experimental quantum characterization of a single qubit device
We present the first full experimental quantum tomographic characterization
of a single-qubit device achieved with a single entangled input state. The
entangled input state plays the role of all possible input states in quantum
parallel on the tested device. The method can be trivially extended to any
n-qubits device by just replicating the whole experimental setup n times.Comment: 4 pages in revtex4 with 4 eps figure
Vapochromic features of new luminogens based on julolidine-containing styrene copolymers
We report on vapochromic films suitable for detecting volatile organic compounds (VOCs), based on new polystyrene copolymers containing julolidine fluorescent molecular rotors (JCAEM). Poly(styrene-co-hydroxyethylmethacrylate) copolymers functionalized with cyanovinyl-julolidine moieties of different compositions were prepared, (P(STY-co-JCAEM)(m) with m = 0.06-0.61). The sensing performance of the spin-coated copolymer films demonstrated significant vapochromism when exposed to VOCs characterized by high vapour pressure and a favourable interaction with the polymer matrix, such as Et2O and CH2Cl2. It is worth mentioning that the fluorescence decrease rate was 7 times faster than that of previously investigated julolidine-based fluorescent molecular rotors dispersed in PS films. This phenomenon was attributed to the better control of the JCAEM moiety distribution in the polymer matrix conferred by the covalent approach, combined with a minimal film thickness of 4 microns. These factors, in concert, strongly accelerate the deactivation pathways of the JCAEM units in the presence of VOCs which interact well. Overall, the present results support the use of julolidine-enriched styrene copolymers as effective chromogenic materials suitable for the fast detection of VOCs
Continuous variable cloning via network of parametric gates
We propose an experimental scheme for the cloning machine of continuous
quantum variables through a network of parametric amplifiers working as
input-output four-port gates.Comment: 4 pages, 2 figures. To appear on Phys. Rev. Let
Julolidine fluorescent molecular rotors as vapour sensing probes in polystyrene films
We introduce a new sensing polymer system for detection of volatile organic compounds (VOCs) based
on the optical response of polystyrene (PS) films doped with julolidine fluorescent molecular rotors
(FMRs). The julolidine FMRs exhibited viscosity-dependent changes in the fluorescence intensity, that
was enhanced when glycerol was added to ethanol solutions and when they were dispersed in PS films.
Thus, reduction in medium mobility slowed down internal motions and allowed for a major radiative
decay pathway. The FMR/PS films were exposed to several VOCs, and showed a significant decrease in
fluorescence emission when exposed to chloroform, whereas a negligible variation in their emission
occurred when methanol was utilized. This vapour sensing behaviour was much more evident when a
perfluorodecyl chain was linked to the julolidine core being the molecule segregated at the film surface.
This responsive behaviour was affected by solvent composition and its reproducible response was easily
determined by luminescence experiments
NITROXIDES AND MALIGNANT HUMAN TISSUES: ELECTRON SPIN RESONANCE IN COLORECTAL NEOPLASTIC AND HEALTHY TISSUES.
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