405 research outputs found
On Macroscopic Energy Gap for -Quantum Mechanical Systems
The q-deformed harmonic oscillator within the framework of the recently
introduced Schwenk-Wess -Heisenberg algebra is considered. It is shown, that
for "physical" values , the gap between the energy levels decreases
with growing energy. Comparing with the other (real) -deformations of the
harmonic oscillator, where the gap instead increases, indicates that the
formation of the macroscopic energy gap in the Schwenk-Wess -Quantum
Mechanics may be avoided.Comment: 6 pages, TeX, PRA-HEP-92/1
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
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
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
On the symmetry of the vacuum in theories with spontaneous symmetry breaking
We review the usual account of the phenomena of spontaneous symmetry breaking
(SSB), pointing out the common misunderstandings surrounding the issue, in
particular within the context of quantum field theory. In fact, the common
explanations one finds in this context, indicate that under certain conditions
corresponding to the situation called SSB, the vacuum of the theory does not
share the symmetries of the Lagrangian. We explain in detail why this statement
is incorrect in general, and in what limited set of circumstances such
situation could arise. We concentrate on the case of global symmetries, for
which we found no satisfactory exposition in the existing literature, and
briefly comment on the case of gauge symmetries where, although insufficiently
publicized, accurate and complete descriptions exist. We briefly discuss the
implications for the phenomenological manifestations usually attributed to the
phenomena of spontaneous symmetry breaking, analyzing which might be affected
by our analysis and which are not. In particular we describe the mass
generation mechanism in a fully symmetric scheme (i.e., with a totally
symmetric vacuum), and briefly discuss the implications of this analysis to the
problem of formation of topological defects in the early universe
Indole derivative interacts with estrogen receptor beta and inhibits human ovarian cancer cell growth
Ovarian cancer remains the leading cause of mortality among gynecological tumors. Estrogen receptor beta (ERÎČ) expression has been suggested to act as a tumor suppressor in epithelial ovarian cancer by reducing both tumor growth and metastasis. ERÎČ expression abnormalities represent a critical step in the development and progression of ovarian cancer: for these reasons, its reâexpression by genetic engineering, as well as the use of targeted ERÎČ therapies, still constitute an important therapeutic approach. 3â{[2âchloroâ1â(4âchlorobenzyl)â5âmethoxyâ6-methylâ1Hâindolâ3âyl]methylene}â5âhydroxyâ6âmethylâ1,3âdihydroâ2Hâindolâ2âone, referred to here as compound 3, has been shown to have cytostatic as well cytotoxic effects on various hormone-dependent cancer cell lines. However, the mechanism of its antiâcarcinogenic activity is not well understood. Here, we offer a possible explanation of such an effect in the human ovarian cancer cell line IGROV1. Chromatin binding protein assay and liquid chromatography mass spectrometry were exploited to localize and quantify compound 3 in cells. Molecular docking was used to prove compound 3 binding to ERÎČ. Mass spectrometryâbased approaches were used to analyze histone postâtranslational modifications. Finally, gene expression analyses revealed a set of genes regulated by the ERÎČ/3 complex, namely CCND1, MYC, CDKN2A, and ESR2, providing possible molecular mechanisms that underline the observed antiproliferative effects
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