Triangle Singularity as the Origin of the a_{1}(1420).

The COMPASS Collaboration experiment recently discovered a new isovector resonancelike signal with axial-vector quantum numbers, the a_{1}(1420), decaying to f_{0}(980)π. With a mass too close to and a width smaller than the axial-vector ground state a_{1}(1260), it was immediately interpreted as a new light exotic meson, similar to the X, Y, Z states in the hidden-charm sector. We show that a resonancelike signal fully matching the experimental data is produced by the decay of the a_{1}(1260) resonance into K^{*}(→Kπ)K[over ¯] and subsequent rescattering through a triangle singularity into the coupled f_{0}(980)π channel. The amplitude for this process is calculated using a new approach based on dispersion relations. The triangle-singularity model is fitted to the partial-wave data of the COMPASS experiment. Despite having fewer parameters, this fit shows a slightly better quality than the one using a resonance hypothesis and thus eliminates the need for an additional resonance in order to describe the data. We thereby demonstrate for the first time in the light-meson sector that a resonancelike structure in the experimental data can be described by rescattering through a triangle singularity, providing evidence for a genuine three-body effect.

First Measurement of Transverse-Spin-Dependent Azimuthal Asymmetries in the Drell-Yan Process.

The first measurement of transverse-spin-dependent azimuthal asymmetries in the pion-induced Drell-Yan (DY) process is reported. We use the CERN SPS 190 GeV/c π^{-} beam and a transversely polarized ammonia target. Three azimuthal asymmetries giving access to different transverse-momentum-dependent (TMD) parton distribution functions (PDFs) are extracted using dimuon events with invariant mass between 4.3 GeV/c^{2} and 8.5 GeV/c^{2}. Within the experimental uncertainties, the observed sign of the Sivers asymmetry is found to be consistent with the fundamental prediction of quantum chromodynamics (QCD) that the Sivers TMD PDFs extracted from DY have a sign opposite to the one extracted from semi-inclusive deep-inelastic scattering (SIDIS) data. We present two other asymmetries originating from the pion Boer-Mulders TMD PDFs convoluted with either the nucleon transversity or pretzelosity TMD PDFs. A recent COMPASS SIDIS measurement was obtained at a hard scale comparable to that of these DY results. This opens the way for possible tests of fundamental QCD universality predictions.

Observation of a New Narrow Axial-Vector Meson a1(1420).

The COMPASS Collaboration at CERN has measured diffractive dissociation of 190 GeV/c pions into the π(-)π(-)π(+) final state using a stationary hydrogen target. A partial-wave analysis (PWA) was performed in bins of 3π mass and four-momentum transfer using the isobar model and the so far largest PWA model consisting of 88 waves. A narrow peak is observed in the f0(980)π channel with spin, parity and C-parity quantum numbers J(PC)=1(++). We present a resonance-model study of a subset of the spin-density matrix selecting 3π states with J(PC)=2(++) and 4(++) decaying into ρ(770)π and with J(PC)=1(++) decaying into f0(980)π. We identify a new a1 meson with mass (1414(-13)(+15)) MeV/c2 and width (153(-23)(+8)) MeV/c2. Within the final states investigated in our analysis, we observe the new a1(1420) decaying only into f0(980)π, suggesting its exotic nature.

Measurement of the charged-pion polarizability.

The COMPASS collaboration at CERN has investigated pion Compton scattering, π(-)γ→π(-)γ, at center-of-mass energy below 3.5 pion masses. The process is embedded in the reaction π(-)Ni→π(-)γNi, which is initiated by 190 GeV pions impinging on a nickel target. The exchange of quasireal photons is selected by isolating the sharp Coulomb peak observed at smallest momentum transfers, Q(2)<0.0015 (GeV/c)(2). From a sample of 63,000 events, the pion electric polarizability is determined to be α(π)=(2.0±0.6(stat)±0.7(syst))×10(-4) fm(3) under the assumption α(π)=-ß(π), which relates the electric and magnetic dipole polarizabilities. It is the most precise measurement of this fundamental low-energy parameter of strong interaction that has been addressed since long by various methods with conflicting outcomes. While this result is in tension with previous dedicated measurements, it is found in agreement with the expectation from chiral perturbation theory. An additional measurement replacing pions by muons, for which the cross-section behavior is unambiguously known, was performed for an independent estimate of the systematic uncertainty.

Palatal obturators in patients after maxillectomy.

Prosthodontic management of palatal defects is fundamental to improve patient's life undergoing to a maxillary surgical treatment. A lot of maxillary defects are a direct consequence of surgical treatment of malformations, neoplasms or trauma. The obturators are prosthesis used to close palatal defects after maxillectomy, to restore masticatory function and to improve speech. The primary goals of the obturator prosthesis are to preserve the remaining teeth and tissue and to provide comfort, function, and aesthetics to the patients. Different materials and retention methods are a characteristic of new types of obturators.

Isolamento de Chaetomium spp. em lesões subcutâneas de um cão: relato de caso / Isolation of Chaetomium spp. on subcutaneous lesions of a dog: case report

Caracterizou-se clinicamente a infecção pelo Chaetomium spp. em um cão, e descreveu-se seu isolamento e identificação. Ao exame dermatológico foram observadas pápulas nas orelhas, no tronco lateral e nos membros pélvicos. Ao rompimento de uma dessas pápulas, fluiu um líquido serosanguinolento com consequente úlcera no local. Foi colhido material para isolamento micológico, por meio de raspado das pápulas da orelha e da cauda. O diagnóstico foi micose subcutânea por Chaetomium spp.

This work aimed to clinically characterize the infection by Chaetomium spp. in a dog, as well as describe its isolation and identification. Upon dermatological exam, papules on ears, lateral trunk and pelvic members were noticed. After the disruption of these papules there was serosanguineous secretion flowed by consequent ulcer in the region. Material for mycological isolation was picked, and a scraping of papules from ear and tail was done. The diagnosis was subcutaneous mycosis caused by Chaetomium spp.

Mechanical evaluation and fem analysis of stress in fixed partial dentures zirconium-ceramic.

OBJECTIVE: Over the last several years, the Finite Element Analysis (FEM) has been widely recognized as a reference method in different fields of study, to simulate the distribution of mechanical stress, in order to evaluate the relative distribution of loads of different nature. The aim of this study is to investigate through the FEM analysis the stress distribution in fixed prostheses that have a core in Zirconia and a ceramic veneer supported by implants. MATERIALS AND METHODS: In this work we investigated the mechanical flexural strength of a ceramic material (Noritake(®)) and a of zirconium framework (Zircodent(®)) and the effects of the manufacturing processes of the material commonly performed during the production of fixed prostheses with CAD/CAM technology. Specifically three point bending mechanical tests were performed (three-point-bending) (1-3), using a machine from Test Equipment Instron 5566(®), on two structures in zirconium framework-ceramic (structures supported by two implant abutments with pontic elements 1 and 2). A further in-depth analysis on the mechanical behavior in flexure of the specimens was conducted carrying out FEM studies in order to compare analog and digital data. RESULTS: The analysis of the data obtained showed that the stresses are distributed in a different way according to the intrinsic elasticity of the structure. The analysis of FPD with four elements, the stresses are mainly concentrated on the surface of the load, while, in the FPD of three elements, much more rigid, the stresses are concentrated near the inner margins of the abutments. The concentration of many stresses in this point could be correlated to chipping (4) that is found in the outer edges of the structure, as a direct result of the ceramic brittleness which opposes the resilience of the structure subjected to bending. CONCLUSIONS: The analysis of the UY linear displacement confirms previous data, showing, in a numerical way, that the presence of the ceramic is related to the lowering of the structure. So, the reference values are those of the linear lowering obtained in the Mechanical Test and in our FEM analysis. zirconium framework with four elements 4,227 10(-2)mm.zirconium framework with ceramic structure with four elements 2,266 10(-2) mm.That suggests that the presence of ceramics halves the flexion capabilities of the prosthetic materials.

First measurement of chiral dynamics in π- γ → π- π- π+.

The COMPASS Collaboration at CERN has investigated the π- γ → π- π- π+ reaction at center-of-momentum energy below five pion masses, sqrt[s]<5m(π), embedded in the Primakoff reaction of 190 GeV pions impinging on a lead target. Exchange of quasireal photons is selected by isolating the sharp Coulomb peak observed at smallest momentum transfers, t'<0.001 GeV2/c2. Using partial-wave analysis techniques, the scattering intensity of Coulomb production described in terms of chiral dynamics and its dependence on the 3π-invariant mass m(3π)=sqrt[s] were extracted. The absolute cross section was determined in seven bins of sqrt[s] with an overall precision of 20%. At leading order, the result is found to be in good agreement with the prediction of chiral perturbation theory over the whole energy range investigated.

Observation of a J(PC)=1-+ exotic resonance in diffractive dissociation of 190   GeV/c π- into π- π- π+.

The COMPASS experiment at the CERN SPS has studied the diffractive dissociation of negative pions into the π- π- π+ final state using a 190 GeV/c pion beam hitting a lead target. A partial wave analysis has been performed on a sample of 420,000 events taken at values of the squared 4-momentum transfer t' between 0.1 and 1 GeV2/c2. The well-known resonances a1(1260), a2(1320), and π2(1670) are clearly observed. In addition, the data show a significant natural-parity exchange production of a resonance with spin-exotic quantum numbers J(PC)=1-+ at 1.66 GeV/c2 decaying to ρπ. The resonant nature of this wave is evident from the mass-dependent phase differences to the J(PC)=2-+ and 1++ waves. From a mass-dependent fit a resonance mass of (1660±10(-64)(+0)) MeV/c2 and a width of (269±21(-64)(+42)) MeV/c2 are deduced, with an intensity of (1.7±0.2)% of the total intensity.

Indication of a deeply bound and compact K- pp state formed in the pp- -> pLambdaK+ reaction at 2.85 GeV.

We have analyzed data of the DISTO experiment on the exclusive pp --> pLambdaK+ reaction at 2.85 GeV to search for a strongly bound compact K- pp(approximately = X) state to be formed in the pp --> K+ + X reaction. The observed spectra of the K+ missing mass and the pLambda invariant-mass with high transverse momenta of p and K+ revealed a broad distinct peak of 26-sigma confidence with a mass M(X)=2267+/-3(stat)+/-5(syst) MeV/c2 and a width Gamma(X)=118+/-8(stat)+/-10(syst) MeV. The enormously large cross section indicates formation of a compact K- pp with a large binding energy of B(K)=103 MeV, which can be a possible gateway toward cold and dense kaonic nuclear matter.

Giant pleomorphic adenoma of the submandibular gland. Case report.

Salivary glands are sites for a great variety of tumors. The parotid gland is the most common site followed by the submandibular gland. The pleomorphic adenoma represents the 60-70% of all tumors involving the major salivary glands, while the submandibular gland is involved in 8% of cases. The pleomorphic adenoma of the submandibular gland is rare and can present difficulty in diagnosis. The heterogeneous histology, a possible malignant transformation, an incomplete capsule that can determine a recurrence, are the most important characteristics of pleomorphic adenoma. A complete surgical removal of the tumor is the treatment of choice. In the case presented, the mass showed an unusual vascularization and remarkable dimensions.

First measurement of the transverse spin asymmetries of the deuteron in semi-inclusive deep inelastic scattering.

First measurements of the Collins and Sivers asymmetries of charged hadrons produced in deep-inelastic scattering of muons on a transversely polarized 6LiD target are presented. The data were taken in 2002 with the COMPASS spectrometer using the muon beam of the CERN SPS at 160 GeV/c. The Collins asymmetry turns out to be compatible with zero, as does the measured Sivers asymmetry within the present statistical errors.

Barkas effect for antiproton stopping in H2.

We report the stopping power of molecular hydrogen for antiprotons of kinetic energy above the maximum (approximately 100 keV) with the purpose of comparing with the proton one. Our result is consistent with a positive difference in antiproton-proton stopping powers above approximately 250 keV and with a maximum difference between the stopping powers of 21%+/-3% at around 600 keV.

Rho(0) meson production in the pp-->pppi(+)pi(-) reaction at 3.67 GeV/c.

Total and differential cross sections for the exclusive reaction pp-->pp rho observed via the pi(+)pi(-) decay channel have been measured at p(beam)=3.67 GeV/c. The observed total meson production cross section is determined to be (23.4+/-0.8+/-8) mu b and is significantly lower than typical cross sections used in model calculations for heavy-ion collisions. The differential cross sections measured indicate a strong anisotropy (approximately cos(theta(CM)(rho)) in the rho(0) meson production.

[Rhino-sinusal endoscopy as a diagnostic and therapeutic treatment in patients undergoing a bone marrow transplantation]. / Endoscopia rino-sinusale quale metodica diagnostica e terapeutica nei pazienti sottoposti a trapianto di midollo osseo.

Immunodepressed subjects appear to present as a common adverse event the infections complication of paranasal sinuses which can lead to an unfavourable clinical evolution spreading the infection to encephalic and endo-orbital tissues. The patients described by the authors present a common clinical history of neoplastic disorders concerning the haemopoietic tissue with an indication for bone marrow transplantation. These patients also demonstrated clinical-radiological evidence of rhino-sinusal impairment with specific maxillary sinus involvement. The clinical condition obliged us to reach a final diagnosis of the origin of rhino-sinusal involvement which clearly appeared by performing imaging diagnostic examinations in order to rapidly establish the correct therapy. The resolution of the rhino-sinus complication allows these patients to follow on the treatment for their own initial pathology. In fact, in order to resume the treatment against haemoblastic disorders, an essential step is to approach the paranasal sinus affection. Endoscopy, in the cases reported, permitted us to obtain a correct diagnosis and to develop a correct antimicrobic therapy, achieving the drainage of the maxillary sinus as well. Endoscopy achieved the same results as radical surgery of the maxillary sinus by the Caldwell-Luc approach, proving less aggressive and reducing operative timing, postoperative recovery timing and intra and post operative haemorrhagic complications. Moreover, endoscopy characteristics present a specific validity in patients with severe general conditions, which are described in the examined group, reducing time for diagnosis and therapy resulting specific to solve the rhino-sinus complication and also particularly important in order to interfere less with the delicate medical therapy for the primary pathology by the sample examined.

[Lymph node metastasis of adenoid cystic carcinoma]. / Metastasi linfonodali nel carcinoma adeno-cistico.

BACKGROUND: The adenocystic carcinoma (ACC) of the head and of the neck is rather uncommon. It is characterized by a very slow biological behaviour, which leads to locoregional recurrences and distant metastasis. Most reports concentrate on the unpredictable long-term behaviour of this tumor, whereas lymph nodes metastasis are not usually discussed in detail. The aim of this study was to evaluate the difficulties connected with the lymph node metastasis in ACC. METHODS: A group of 33 patients from 1980 to 1998, was observed. These patients have been subjected to surgical treatment in the Maxillo-Facial Surgery Department of the Policlinico-Umberto I of Rome. RESULTS: Among 33 patients with ACC, 10 patients (30%) revealed, initially or during observation, cervical lymph node metastasis, which is a most common event in male subjects (70%). The lymph node involvement is much more common in carcinomas localized in the parotid and in the sublingual glands with a solid rather than a tubular histologic pattern. Direct correlation between age and metastasis lymph node involvement have not been documented. CONCLUSIONS: Surgery for node disease has a very little impact on the locoregional and on the distant metastasis evolution of the tumor. Thus, our protocol of treatment of lymph nodes metastatic lesions follows the trend of most of the international authors, considering that the neck dissection should be performed only with a lymph adenopathy clinically evident or strongly suspected.