147 research outputs found
Bethe ansatz solution of the anisotropic correlated electron model associated with the Temperley-Lieb algebra
A recently proposed strongly correlated electron system associated with the
Temperley-Lieb algebra is solved by means of the coordinate Bethe ansatz for
periodic and closed boundary conditions.Comment: 21 page
Renormalization group trajectories from resonance factorized S-matrices
We propose and investigate a large class of models possessing resonance
factorized S-matrices. The associated Casimir energy describes a rich pattern
of renormalization group trajectories related to flows in the coset models
based on the simply laced Lie Algebras. From a simplest resonance S-matrix,
satisfying the ``-property'', we predict new flows in non-unitary
minimal models.Comment: (7 pages) (no figures included
Jorge A. Swieca's contributions to quantum field theory in the 60s and 70s and their relevance in present research
After revisiting some high points of particle physics and QFT of the two
decades from 1960 to 1980, I comment on the work by Jorge Andre Swieca. I
explain how it fits into the quantum field theory during these two decades and
draw attention to its relevance to the ongoing particle physics research. A
particular aim of this article is to direct thr readers mindfulness to the
relevance of what at the time of Swieca was called "the Schwinger Higgs
screening mechanism". which, together with recent ideas which generalize the
concept of gauge theories, has all the ingredients to revolutionize the issue
of gauge theories and the standard model.Comment: 49 pages, expansion and actualization of text, improvement of
formulations and addition of many references to be published in EPJH -
Historical Perspectives on Contemporary Physic
On scaling fields in Ising models
We study the space of scaling fields in the symmetric models with the
factorized scattering and propose simplest algebraic relations between form
factors induced by the action of deformed parafermionic currents. The
construction gives a new free field representation for form factors of
perturbed Virasoro algebra primary fields, which are parafermionic algebra
descendants. We find exact vacuum expectation values of physically important
fields and study correlation functions of order and disorder fields in the form
factor and CFT perturbation approaches.Comment: 2 Figures, jetpl.cl
Intrinsic rheological behavior of limestone calcined clay cementitious (LC3) binders for automated construction: Effect of calcium sulfate varieties
As the concrete industry moves toward sustainable, automated construction, understanding the rheological behavior of alternative binders is essential. In particular, the rheology of limestone calcined clay cement (LC3) is extremely sensitive to the type of calcium sulfate used. This study systematically investigates the impact of anhydrite (CaSO4), bassanite (CaSO4·0.5 H2O), and gypsum (CaSO4·2 H2O) on hydration kinetics, structural build-up, and workability of LC3 pastes. Isothermal calorimetry, rotational and oscillatory rheometry (Large-Amplitude Oscillatory Shear (LAOS) tests) were used to decouple the interplays between sulfate dissolution, hydration and thixotropic behavior. The results indicate that bassanite accelerates early-age structuration due to its rapid dissolution and ettringite formation, yielding a high structuration rate (Athix = 0.5 Pa/min) and optimal shear stress evolution (up to 102 Pa). Conversely, gypsum retards structuration and extends workability beyond 140 minutes, but compromises early stiffening. Anhydrite, despite its coarser morphology, exhibited intermediate behavior with rapid workability reduction. LAOS analysis also identified distinct viscoelastic thresholds. Pastes with bassanite reached critical strain (10−3) and crossover strain (10−2) at minimal deformation, ideal for automated construction, while gypsum formulations showed delayed stiffening. This study demonstrates that sulfate selection directly controls open time, with bassanite formulations requiring a 90-minute operational time frame to balance extrudability and layer stability. These findings underscore the need to tailor calcium sulfate type to application-specific rheological demands and offer a pathway to optimize LC3 binders for automated processes such as robotic shotcreting and 3D concrete printing
Electromyographycal findings in human chronic Chaga's disease
An electromyographical investigation of 80 patients with chronic Chagas' disease was made. It was found that 79% of the studied patients had EMG manifestations of old and chronic denervation of the upper and lower limbs without clinical features of nervous system involvement
Gene-specific repair of Pt/DNA lesions and induction of apoptosis by the oral platinum drug JM216 in three human ovarian carcinoma cell lines sensitive and resistant to cisplatin
JM216, an oral platinum drug entering into phase III clinical trial, exhibited comparable cytotoxicity to cisplatin in three human ovarian carcinoma cell lines: the sensitive (CH1), acquired resistant (CH1cisR) and intrinsically resistant (SKOV-3). Platinum accumulation and binding to DNA were similar in each of the three cell lines at equimolar doses, indicating that the resistant cell lines could tolerate higher intracellular platinum levels and platinum bound to DNA at IC50 concentrations of drug. Comparison with cisplatin demonstrated that intracellular platinum levels were marginally higher with JM216, but that platinum binding to DNA was similar for the two drugs in each of the cell lines. Each of the cell lines exhibited an ability to repair JM216 induced platinum/DNA lesions in the N-ras gene (gene-specific repair) at equitoxic concentrations of drug. However, this occurred to a greater extent in the two resistant cell lines such that by 24 h the CH1cisR and SKOV-3 had removed 72% and 67% respectively compared with approximately 32% for the CH1. Reduced gene-specific repair capacity in CH1 cells was also seen following incubation with 25 μM (or 5 μM – 2 × IC50) cisplatin, whereas the CH1cisR and SKOV-3 cell lines were repair proficient. JM216 induced apoptosis in the three cell lines following a 2h incubation with 2 × the IC50 of drug. Fluorescent microscopy of cells stained with propidium iodide showed that the detached cell population displayed typical apoptotic nuclei. Furthermore, field inversion gel electrophoresis demonstrated the presence of DNA fragments approximately 23–50 kb in size, indicative of apoptosis, in the detached cells. JM216 induced an S phase slow down in each of the three cell lines accompanied by a G2 block in the CH1 pair. Incubation with this concentration of JM216 also resulted in the induction of p53 in the CH1 and CH1cisR. These studies suggest that the relative sensitivity of the CH1 cell line to cisplatin and JM216 is at least partly attributable to a deficiency in gene-specific repair. The oral platinum drug, JM216, exerts its cytotoxic effects through the induction of apoptosis following a slow-down in S phase in both the sensitive and resistant lines. © 1999 Cancer Research Campaig
Integrable sigma models with theta=pi
A fundamental result relevant to spin chains and two-dimensional disordered
systems is that the sphere sigma model with instanton coupling theta=pi has a
non-trivial low-energy fixed point and a gapless spectrum. This result is
extended to two series of sigma models with theta=pi: the SU(N)/SO(N) sigma
models flow to the SU(N)_1 WZW theory, while the O(2N)/O(N)\times O(N) models
flow to O(2N)_1 (2N free Majorana fermions). These models are integrable, and
the exact quasiparticle spectra and S matrices are found. One interesting
feature is that charges fractionalize when theta=pi. I compute the energy in a
background field, and verify that the perturbative expansions for \theta=0 and
pi are the same as they must be. I discuss the flows between the two sequences
of models, and also argue that the analogous sigma models with Sp(2N) symmetry,
the Sp(2N)/U(N) models, flow to Sp(2N)_1.Comment: 31 pages, 2 figures. v2: corrects many typos. v3: corrects more
typos, adds referenc
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