533 research outputs found
Resonant sneutrino production at Tevatron Run II
We consider the single chargino production at Tevatron as induced by the resonant sneutrino
production via a dominant \RPV coupling of type \l'_{ijk} L_i Q_j D_k^c.
Within a supergravity model, we study the three leptons final state. The
comparison with the expected background demonstrate that this signature allows
to extend the sensitivity on the \susyq mass spectrum beyond the present LEP
limits and to probe the relevant \RPV coupling down to values one order of
magnitude smaller than the most stringent low energy indirect bounds. The
trilepton signal offers also the opportunity to reconstruct the neutralino mass
in a model independent way with good accuracy.Comment: 4 page
Measurement of healing area using planimetry after applying low-intensity ultrasound to the skin of rats
CONTEXTUALIZAÇÃO: A planimetria é um método utilizado para avaliar a evolução da cicatrização de feridas. A planimetria computacional é um método ainda em experimentação, mas cujas vantagens têm sido demonstradas em várias investigações. OBJETIVOS: Avaliar os efeitos do ultra-som pulsado de baixa intensidade sobre a cicatrização de lesão cutânea produzida na região dorsal de ratos, por meio da planimetria computacional. MATERIAIS E MÉTODOS: Utilizou-se 60 ratos machos Wistar (peso médio de 300g) divididos em dois grupos com 30 animais cada, de acordo com o tratamento: 1) irradiação simulada (controle); 2) irradiação efetiva (Freqüência fundamental de 1,5MHz, freqüência de repetição de pulsos de 1KHz, largura de pulso de 200µs, intensidade de 30mW/cm² SATA, dez minutos de aplicação em dias alternados). Cada grupo foi subdividido em três grupos, de acordo com o período de irradiação ultra-sônica, de três, sete e 14 dias, respectivamente, e a cicatrização foi avaliada por meio da planimetria, um decalque da lesão sendo obtido em papel especial, digitalizado e medido ao computador por meio de um programa gráfico. Análise estatística pelo método não-paramétrico de Mann-Whitney. RESULTADOS: Houve aumento significante (p<0,05) da área cicatrizada no grupo 2 (141,88±18,50mm²) em relação ao grupo 1 (117,38±15,14mm²), no 14º dia. Não houve diferenças significantes entre os grupos nos demais períodos. CONCLUSÕES: O ultra-som pulsado de baixa intensidade estimula a cicatrização cutânea por segunda intenção em condições experimentais. A planimetria computacional mostrou-se um recurso de baixo custo, fácil manuseio e de aplicabilidade clínica.BACKGROUND: Planimetry is a method used to evaluate the progression of skin wound healing. Computerized planimetry is still an experimental method, but its advantages have been demonstrated in several investigations. OBJECTIVE: To evaluate the effects of low-intensity pulsed ultrasound on the healing of a skin lesion produced on the dorsal region of rats, by means of computerized planimetry. METHODS: Sixty male Wistar rats of mean weight 300g were used. They were divided into two groups according to the treatment applied: 1) simulated irradiation (control); 2) effective irradiation (fundamental frequency 1.5MHz, pulse repetition frequency 1KHz, pulse width 200µs, SATA intensity 30mW/cm² and application for ten minutes on alternate days). Each group was divided into three subgroups according to the length of time for which ultrasound irradiation was applied of three, seven and 14 days, respectively, and healing was evaluated by means of planimetry; a tracing of the wound was obtained on special paper and this was digitized and measured by means of a graphing software. Statistical analysis was performed using the Mann-Whitney non-parametric method. RESULTS: The healed area was significantly greater (p<0.05) in group 2 (141.88±18.50mm²) than in group 1 (117.38±15.14mm²) on the 14th day. There were no significant differences between the subgroups for the other experimental periods. CONCLUSIONS: Low-intensity pulsed ultrasound irradiation stimulated secondary skin healing under these experimental conditions. Computerized planimetry was shown to be a low cost method that was easy to use and present clinical applicability
The biology and ecology of Valencia letourneuxi Sauvage 1880 (Valenciidae) - Prospects for conservation
Data are provided on the distribution, abundance, early development and biology of the endangered Greek endemic species Valencia letourneuxi Sauvage 1880, along with a record of its occurrence at new localities. V. letourneuxi is a small-bodied and short-lived insectivorous species, exhibiting cryptic colouration and sexual dimorphism. It matures in the first year of life, reproduces serially in late spring and summer, and deposits spherical eggs, around 2 mm, on aquatic plants. Most morphometric characters show size-specific trends, which complicate comparisons among populations or with other species. Of specific systematic importance is the relative position of the anal and dorsal fins, which remains almost unaltered throughout development, and allows safe distinction from A. fasciatus. The species was found mostly in deep areas with clean and slow running water, usually associated with freshwater springs. Rich submerged vegetation is the prominent ecological feature of all sites in which the species was found. Using as criteria of rarity the limited geographic distribution, the confinement of the species in few localities of each aquatic system and the low local densities, V. letourneuxi can be characterised as a "restricted and locally rare species". The restricted distribution, coupled with the narrow ecological requirements, makes the species vulnerable to extinction. Its disappearance from at least four aquatic systems and the serious population decline in a number of other systems seems to be connected with habitat loss or degradation caused by human activities. The prospects of conservation are discussed
The ESO Key-Programme ``A Homogeneous Bright QSO Survey'' - I The Methods and the ``Deep'' Fields
This is the first paper in a series aimed at defining a statistically
significant sample of QSOs in the range and .
The selection is carried out using direct plates obtained at the ESO and UK
Schmidt Telescopes, scanned with the COSMOS facility and searched for objects
with an ultraviolet excess. Follow-up spectroscopy, carried out at ESO La
Silla, is used to classify each candidate. In this initial paper, we describe
the scientific objectives of the survey; the selection and observing techniques
used. We present the first sample of 285 QSOs () in a 153 deg
area, covered by the six ``deep'' fields, intended to obtain significant
statistics down with unprecedented photometric accuracy. From
this database, QSO counts are determined in the magnitude range .Comment: 21 pages uuencoded compressed postscript, to appear in Astronomy and
Astrophysics Supplements, 199
Knockout of proton-neutron pairs from O with electromagnetic probes
After recent improvements to the Pavia model of two-nucleon knockout from
O with electromagnetic probes the calculated cross sections are compared
to experimental data from such reactions. Comparison with data from a
measurement of the O(e,epn) reaction show much better agreement
between experiment and theory than was previously observed. In a comparison
with recent data from a measurement of the O(,pn) reaction the
model over-predicts the measured cross section at low missing momentum.Comment: 6 pages, 5 figure
Theatrical performance in the tourism industry: An Importance-Satisfaction Analysis
Theatrical performances have been developed quickly in many tourism destinations in China; however, little research has been focused on this important area. This study examined tourists’ perceptions towards The Romance of the Song Dynasty, one of the most successful performances targeted at tourists in China. Using Importance-Satisfaction Analysis (ISA), this study revealed that the most important and satisfied attributes by tourists were primarily associated with the core service attributes (i.e., performing art), whereas the most unimportant and dissatisfied attributes by tourists were mainly associated with the peripheral service attributes (i.e., venue environment, service, and tourist management). Both theoretical and practical contributions were provided in this study
Probing the N = 32 shell closure below the magic proton number Z = 20: Mass measurements of the exotic isotopes 52,53K
The recently confirmed neutron-shell closure at N = 32 has been investigated
for the first time below the magic proton number Z = 20 with mass measurements
of the exotic isotopes 52,53K, the latter being the shortest-lived nuclide
investigated at the online mass spectrometer ISOLTRAP. The resulting
two-neutron separation energies reveal a 3 MeV shell gap at N = 32, slightly
lower than for 52Ca, highlighting the doubly-magic nature of this nuclide.
Skyrme-Hartree-Fock-Boguliubov and ab initio Gorkov-Green function calculations
are challenged by the new measurements but reproduce qualitatively the observed
shell effect.Comment: 5 pages, 5 figure
Measuring Atmospheric Neutrino Oscillations with Neutrino Telescopes
Neutrino telescopes with large detection volumes can demonstrate that the
current indications of neutrino oscillation are correct or if a better
description can be achieved with non-standard alternatives. Observations of
contained muons produced by atmospheric neutrinos can better constrain the
allowed region for oscillations or determine the relevant parameters of
non-standard models. We analyze the possibility of neutrino telescopes
measuring atmospheric neutrino oscillations. We suggest adjustments to improve
this potential. An addition of four densely-instrumented strings to the AMANDA
II detector makes observations feasible. Such a configuration is competitive
with current and proposed experiments.Comment: 36 pages, 21 figures, revte
Beating the channel capacity limit for linear photonic superdense coding
Dense coding is arguably the protocol that launched the field of quantum
communication. Today, however, more than a decade after its initial
experimental realization, the channel capacity remains fundamentally limited as
conceived for photons using linear elements. Bob can only send to Alice three
of four potential messages owing to the impossibility of carrying out the
deterministic discrimination of all four Bell states with linear optics,
reducing the attainable channel capacity from 2 to log_2 3 \approx 1.585 bits.
However, entanglement in an extra degree of freedom enables the complete and
deterministic discrimination of all Bell states. Using pairs of photons
simultaneously entangled in spin and orbital angular momentum, we demonstrate
the quantum advantage of the ancillary entanglement. In particular, we describe
a dense-coding experiment with the largest reported channel capacity and, to
our knowledge, the first to break the conventional linear-optics threshold. Our
encoding is suited for quantum communication without alignment and satellite
communication.Comment: Letter: 6 pages, 4 figures. Supplementary Information: 4 pages, 1
figur
A realistic pattern of fermion masses from a five-dimensional SO(10) model
We provide a unified description of fermion masses and mixing angles in the
framework of a supersymmetric grand unified SO(10) model with anarchic Yukawa
couplings of order unity. The space-time is five dimensional and the extra flat
spatial dimension is compactified on the orbifold ,
leading to Pati-Salam gauge symmetry on the boundary where Yukawa interactions
are localised. The gauge symmetry breaking is completed by means of a rather
economic scalar sector, avoiding the doublet-triplet splitting problem. The
matter fields live in the bulk and their massless modes get exponential
profiles, which naturally explain the mass hierarchy of the different fermion
generations. Quarks and leptons properties are naturally reproduced by a
mechanism, first proposed by Kitano and Li, that lifts the SO(10) degeneracy of
bulk masses in terms of a single parameter. The model provides a realistic
pattern of fermion masses and mixing angles for large values of . It
favours normally ordered neutrino mass spectrum with the lightest neutrino mass
below 0.01 eV and no preference for leptonic CP violating phases. The right
handed neutrino mass spectrum is very hierarchical and does not allow for
thermal leptogenesis. We analyse several variants of the basic framework and
find that the results concerning the fermion spectrum are remarkably stable.Comment: 30 pages, 7 figures, 4 table
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