Localization and symmetries

The violation of the Noether relation between symmetries and charges is reduced to the time dependence of the charge associated to a conserved current. For the U(1) gauge symmetry a non-perturbative control of the charge commutators is obtained by an analysis of the Coulomb charged fields. From this, in the unbroken case we obtain a correct expression for the electric charge on the Coulomb states, its superselection and the presence of massless vector bosons; in the broken case, we obtain a general non-perturbative version of the Higgs phenomenon, i.e. the absence of massless Goldstone bosons and of massless vector bosons. The conservation of the (gauge dependent) current associated to the U(1) axial symmetry in QCD is shown to be compatible with the time dependence of the corresponding charge commutators and a non-vanishing eta' mass, as a consequence of the non locality of the (conserved) current.Comment: Invited contribution to ``The Quantum Universe'', dedicated to G. Ghirardi for his 70th birthda

Bounds on heavy chiral fermions

We derive the low-energy electroweak effective lagrangian for the case of additional heavy, unmixed, sequential fermions. Present data still allow for the presence of a new quark and/or lepton doublet with masses greater than M_Z/2, provided that these multiplets are sufficiently degenerate. Deviations of the effective lagrangian predictions from a full one-loop computation are sizeable only for fermion masses close to the threshold M_Z/2. Some of the constraints on new sequential fermions coming from accelerator results and cosmological considerations are presented. We point out that the new fermions can significantly affect the production and decay rate into \gamma \gamma of the intermediate Higgs at LHC

Tricalcium phosphate endosseous implants in dentistry: ultrastructural findings

β-Tricalcium phosphate magnesium substitued (β-TCMP), consisting of one part small unsintered and one part large sintered granules was placed in upper and lower jaw surgical cavities of monkeys. At light and transmission electron microscope the biopsies taken at 2, 4, 8 and 24 weeks showed that both sintered and unsintered granules were well tolerated by the host tissue and result biodegradable over time.β-TCMP may stimulate the direction of bone growth enhancing osteoblasts activity and new bone deposition in direct contact and in the micropores of the biomaterial. β-TCMP containing Mg ions reabsorbs slowly when in sintered granules form and rapidly as unsintered granules. When it is placed in bone cavities, if bone reabsorption is biologically necessary, the biomaterial can be reabsorbed with bone, while if osteogenesis is required β-TCMP provides a more durable matrix to support new bone growth.Le β-phosphate tricalcique contenant à ions Mg (β-TCMP) et constitué à parts égales de fins granules non frittés et de larges granules frittés, est introduit dans des cavités chirurgicales pratiquées dans les maxillaires supérieurs et inférieurs de singes.Des biopsies pratiquées à 2, 4, 8 et 24 semaines ont été examinées au microscope optique et électronique à transmission.Les granules frittés et non frittés sont bien tolérés par les tissus hôtes et sont biodégradés avec le temps.Les observations histologiques montrent aussi que le β-TCMP peut orienter la direction de la croissance osseuse en stimulant l’activité des ostéoblastes et le dépôt d’os nouveau aussi bien autour des biomatériaux que dans leur micropores. Le β-TCMP contenant les ions Mg est réabsorbé lentement lorsqu’il se présente sous la forme de granules frittés, et rapidement lorsqu’il est sous la forme de granules non frittés.Lorsqu’il est introduit dans les cavités osseuses, si la réabsorption osseuse est biologiquement nécessaire, le biomatériau peut être réabsorbé avec l’os, tandis que si c’est l’ostéogenèse qui est sollicitée, β-TCMP fournit une matrice durable comme support à la croissance d’os nouveau

On Macroscopic Energy Gap for qq-Quantum Mechanical Systems

The q-deformed harmonic oscillator within the framework of the recently introduced Schwenk-Wess $q$-Heisenberg algebra is considered. It is shown, that for "physical" values $q\sim1$, the gap between the energy levels decreases with growing energy. Comparing with the other (real) $q$-deformations of the harmonic oscillator, where the gap instead increases, indicates that the formation of the macroscopic energy gap in the Schwenk-Wess $q$-Quantum Mechanics may be avoided.Comment: 6 pages, TeX, PRA-HEP-92/1

Mathematical structure of the temporal gauge

The mathematical structure of the temporal gauge of QED is critically examined in both the alternative formulations characterized by either positivity or regularity of the Weyl algebra. The conflict between time translation invariance and Gauss law constraint is shown to lead to peculiar features. In the positive case only the correlations of exponentials of fields exist (non regularity), the space translations are not strongly continuous, so that their generators do not exist, a theta vacuum degeneracy occurs, associated to a spontaneous symmetry breaking. In the indefinite case the spectral condition only holds in terms of positivity of the energy, gauge invariant theta-vacua exist on the observables, with no extension to time translation invariant states on the field algebra, the vacuum is faithful on the longitudinal algebra and a KMS structure emerges. Functional integral representations are derived in both cases, with the alternative between ergodic measures on real random fields or complex Gaussian random fields.Comment: Late

Topological mass mechanism and exact fields mapping

We present a class of mappings between models with topological mass mechanism and purely topological models in arbitrary dimensions. These mappings are established by directly mapping the fields of one model in terms of the fields of the other model in closed expressions. These expressions provide the mappings of their actions as well as the mappings of their propagators. For a general class of models in which the topological model becomes the BF model the mappings present arbitrary functions which otherwise are absent for Chern-Simons like actions. This work generalizes the results of [1] for arbitrary dimensions.Comment: 11 page

Probability density functions of photochemicals over a coastal area of Northern Italy

The present paper surveys the findings of experimental studies and analyses of statistical probability density functions (PDFs) applied to air pollutant concentrations to provide an interpretation of the ground-level distributions of photochemical oxidants in the coastal area of Ravenna (Italy). The atmospheric pollution data set was collected from the local environmental monitoring network for the period 1978-1989. Results suggest that the statistical distribution of surface ozone, once normalised over the solar radiation PDF for the whole measurement period, follows a log-normal law as found for other pollutants. Although the Weibull distribution also offers a good fit of the experimental data, the area’s meteorological features seem to favour the former distribution once the statistical index estimates have been analysed. Local transport phenomena are discussed to explain the data tail trends

A prospective evaluation of persistence on antihypertensive treatment with different antihypertensive drugs in clinical practice

Persistence on treatment affects the efficacy of antihypertensive treatment. We prospectively investigated the persistence on therapy and the extent of blood pressure (BP) control in 347 hypertensive patients (age 59.4 +/- 6 years) randomly allocated to a first-line treatment with: angiotensin-converting enzyme (ACE) inhibitors, calcium-channel blockers (CCBs), beta-blockers, angiotensin-II receptor blockers (ARBs), or diuretics and followed-up for 24-months. Persistence on treatment was higher in patients treated with ARBs (68.5%) and ACE inhibitors (64.5%) vs CCBs (51.6%; p < 0.05), beta-blockers (44.8%, p < 0.05), and diuretics (34.4%, p < 0.01). No ARB, ACE inhibitor, beta-blocker, or diuretic was associated with a higher persistence in therapy compared with the other molecules used in each therapeutic class. The rate of persistence was significantly higher in patients treated with lercanidipine vs others CCBs (59.3% vs 46.6%, p < 0.05). Systolic and diastolic BP was decreased more successfully in patients treated with ARBs (-11.2/-5.8 mmHg), ACE inhibitors (-10.5/-5.1 mmHg), and CCBs (-8.5/-4.6 mmHg) compared with beta-blockers (-4.0/-2.3 mmHg p < 0.05) and diuretics (-2.3/-2.1 mmHg, p < 0.05). No ARB, ACE inhibitor, beta-blocker, or diuretic was associated with a higher BP control compared with the other molecules used in each therapeutic class. A trend toward a better BP control was observed in response to lercanidipine vs other CCBs (p = 0.059). The present results confirm the importance of persistence on treatment for the management of hypertension in clinical practice

Continuum Limit of 2D2D Spin Models with Continuous Symmetry and Conformal Quantum Field Theory

According to the standard classification of Conformal Quantum Field Theory (CQFT) in two dimensions, the massless continuum limit of the $O(2)$ model at the Kosterlitz-Thouless (KT) transition point should be given by the massless free scalar field; in particular the Noether current of the model should be proportional to (the dual of) the gradient of the massless free scalar field, reflecting a symmetry enhanced from $O(2)$ to $O(2)\times O(2)$. More generally, the massless continuum limit of a spin model with a symmetry given by a Lie group $G$ should have an enhanced symmetry $G\times G$. We point out that the arguments leading to this conclusion contain two serious gaps: i) the possibility of `nontrivial local cohomology' and ii) the possibility that the current is an ultralocal field. For the $2D$ $O(2)$ model we give analytic arguments which rule out the first possibility and use numerical methods to dispose of the second one. We conclude that the standard CQFT predictions appear to be borne out in the $O(2)$ model, but give an example where they would fail. We also point out that all our arguments apply equally well to any $G$ symmetric spin model, provided it has a critical point at a finite temperature.Comment: 19 page

Gupta–Bleuler Quantization of the Maxwell Field in Globally Hyperbolic Space-Times

We give a complete framework for the Gupta–Bleuler quantization of the free electromagnetic field on globally hyperbolic space-times. We describe one-particle structures that give rise to states satisfying the microlocal spectrum condition. The field algebras in the so-called Gupta–Bleuler representations satisfy the time-slice axiom, and the corresponding vacuum states satisfy the microlocal spectrum condition. We also give an explicit construction of ground states on ultrastatic space-times. Unlike previous constructions, our method does not require a spectral gap or the absence of zero modes. The only requirement, the absence of zero-resonance states, is shown to be stable under compact perturbations of topology and metric. Usual deformation arguments based on the time-slice axiom then lead to a construction of Gupta–Bleuler representations on a large class of globally hyperbolic space-times. As usual, the field algebra is represented on an indefinite inner product space, in which the physical states form a positive semi-definite subspace. Gauge transformations are incorporated in such a way that the field can be coupled perturbatively to a Dirac field. Our approach does not require any topological restrictions on the underlying space-time