2,458 research outputs found
Resonances in twisted quantum waveguides
In this paper we consider embedded eigenvalues of a Schroedinger Hamiltonian
in a waveguide induced by a symmetric perturbation. It is shown that these
eigenvalues become unstable and turn into resonances after twisting of the
waveguide. The perturbative expansion of the resonance width is calculated for
weakly twisted waveguides and the influence of the twist on resonances in a
concrete model is discussed in detail.Comment: 15 Page
Magnetic properties of PrCu at high pressure
We report a study of the low-temperature high-pressure phase diagram of the
intermetallic compound PrCu, by means of molecular-field calculations and
Cu nuclear-quadrupole-resonance (NQR) measurements under pressure.
The pressure-induced magnetically-ordered phase can be accounted for by
considering the influence of the crystal electric field on the electron
orbitals of the Pr ions and by introducing a pressure-dependent exchange
interaction between the corresponding local magnetic moments. Our experimental
data suggest that the order in the induced antiferromagnetic phase is
incommensurate. The role of magnetic fluctuations both at high and low
pressures is also discussed.Comment: 7 pages, 6 figures, submitted to Eur. Phys. J.
Progress towards Bell-type polarization experiment with thermal neutrons
Experimental tests of Bell-type inequalities distinguishing between quantum
mechanics and local realistic theories remain of considerable interest if
performed on massive particles, for which no conclusive result has yet been
obtained. Only two-particle experiments may specifically test the concept of
spatial nonlocality in quantum theory, whereas single-particle experiments may
generally test the concept of quantum noncontextuality. Here we have performed
the first Bell-type experiment with a beam of thermal-neutron pairs in the
singlet state of spin, as originally suggested by J. S. Bell. These
measurements confirm the quantum-theoretical predictions, in agreement with the
results of the well-known polarization experiments carried out on optical
photons years ago
The Barthel index: italian translation, adaptation and validation
The Barthel Index (BI) is widely used to measure disability also in
Italy, although a validated and culturally adapted Italian version of
BI has not been produced yet. This article describes the translation
and cultural adaptation into Italian of the original 10-item version of
BI, and reports the procedures for testing its validity and reliability.
The cultural adaptation and validation process was based on data
from a cohort of disabled patients from two different Rehabilitation
Centers in Rome, Italy.
Forward and backward translation method was adopted by
qualified linguist and independent native English official translators.
The scale obtained was reviewed by 20 experts in psychometric
sciences. The Italian adapted version of the BI was then produced
and validated. A total number of 180 patients were submitted to the
adapted scale for testing its acceptability and internal consistency.
The total time of compilation was 5 ± 2,6 minutes (range 3-10).
Validation of the scale was performed by 7 trained professional
therapists that submitted both the translated and the adapted
versions to a group of 62 clinically stable patients (T-test=-2.051
p=0.05). The internal consistency by Cronbach’s alpha resulted
equal to 0.96. Test – retest intra – rater reliability was evaluated
on 35 cases; at test-retest was ICC=0.983 (95%IC: 0.967-0.992).
This is the first study that reports translation, adaptation and
validation of the BI in Italian language. It provides a new tool for
professionals to measure functional disability when appraising
Italian speaking disable patients in health and social care settings
along the continuum of care
Lotta alla mosca delle olive in olivicoltura integrata e biologica
Bactrocera oleae, fitofago chiave dell’agroecosistema olivo, è presente in Italia in tutti gli areali interessati dalla coltura, tranne in alcune aree caratterizzate da maggiore altitudine dove il fattore termico non consente lo sviluppo della specie. Il dittero è fortemente legato alle temperature che del resto condizionano anche la fenologia dell’olivo; in effetti il numero di generazioni che la mosca può completare nell’anno varia da 1 fino a 4-5 in zone con temperature medie annue elevate (zone costiere e/o meridionali). La pericolosità della specie è pertanto legata al numero di generazioni e all’andamento climatico che, a seconda dell’annata e della zona, possono variare sensibilmente condizionando la densità di popolazione e quindi il grado di dannosità potenziale del fitofago. Recenti ricerche sul comportamento e sulla biologia del tefritide hanno messo in evidenza come il fitofago, nel tempo, abbia contratto con i batteri una simbiosi mutualistica che permette al dittero di aumentare il proprio potenziale biotico. Nel presente articolo, dopo un breve excursus sulla biologia e sui danni causati dal fitofago, viene fatto il quadro delle attuali strategie di lotta ammesse nei protocolli dell’olivicoltura integrata e biologica.The control of the olive fruit fly in integrated and organic olive crops. Bactrocera oleae (Rossi) is the key pest of the olive agroecosystem; it is distributed in all Italian olive crops, except in some areas at higher altitude where low temperatures do not allow the development of the fly. The olive fruit fly development is strictly affected by temperature. It can complete from one up to five generations per year in areas with high annual average temperature (coastal and/ or southern areas). The harmfulness of the species is related to the number of generations and weather conditions which may fluctuate considerably year by year, region by region. Recent researches on behavior and natural history of the tephritid fly have pointed out that it has developed a mutualistic symbiosis with bacteria which allows an increase of its growth rate. In this article authors present control strategies permitted in integrated and organic olive crops.
The currently widespread early harvesting and timely milling reduce the harmful influence of late olive fruit fly infestations; together with mass trapping and with repellent/ oviposition deterrent sprays by copper products and clays, these practices allow an increasingly sustainable effective
control of the olive fruit fl
Management of patients with Graves' disease and orbital involvement: role of spectral domain optical coherence tomography
PURPOSE:
To investigate the role of choroidal thickness evaluation with spectral domain optical coherence tomography (SDOCT) and enhanced depth imaging (EDI) technique in the management of patients with Graves' disease and orbitopathy (GO).
METHODS:
Thirty-six eyes of 18 patients with GO and 36 eyes of 18 age-matched control subjects were included in this retrospective observational study. All the subjects underwent a complete ophthalmological evaluation, including clinical activity score (CAS) and exophthalmometry. The SDOCT images of the choroid were obtained by EDI modality.
RESULTS:
Choroidal thickness was significantly increased in GO than in control eyes (p < 0.01). A significant correlation was found between choroidal thickness and CAS, proptosis, and the duration of disease (p < 0.05).
CONCLUSION:
This study shows that choroidal thickness, evaluated with EDI-OCT, is significantly increased in patients with GO and correlates with the activity of the disease, proptosis, and duration of the disease. The choroidal thickening may reflect the ocular hemodynamic changes, and enhanced depth imaging optical coherence tomography may be a useful tool for the evaluation of orbital congestion and management of patients with Graves' disease and orbital involvement
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