Rotating 5D-Kaluza-Klein Space-Times from Invariant Transformations

Using invariant transformations of the five-dimensional Kaluza-Klein (KK) field equations, we find a series of formulae to derive axial symmetric stationary exact solutions of the KK theory starting from static ones. The procedure presented in this work allows to derive new exact solutions up to very simple integrations. Among other results, we find exact rotating solutions containing magnetic monopoles, dipoles, quadripoles, etc., coupled to scalar and to gravitational multipole fields.Comment: 24 pages, latex, no figures. To appear in Gen. Rel. Grav., 32, (2000), in pres

Plasma membrane-specific interactome analysis reveals calpain 1 as a druggable modulator of rescued Phe508del-CFTR cell surface stability

Cystic fibrosis (CF) is a genetic disease caused by mutations in the gene encoding CF transmembrane conductance regulator (CFTR), a chloride channel normally expressed at the surface of epithelial cells. The most frequent mutation, resulting in Phe-508 deletion, causes CFTR misfolding and its premature degradation. Low temperature or pharmacological correctors can partly rescue the Phe508del-CFTR processing defect and enhance trafficking of this channel variant to the plasma membrane (PM). Nevertheless, the rescued channels have an increased endocytosis rate, being quickly removed from the PM by the peripheral protein quality-control pathway. We previously reported that rescued Phe508del-CFTR (rPhe508del) can be retained at the cell surface by stimulating signaling pathways that coax the adaptor molecule ezrin (EZR) to tether rPhe508del–Na+/H+-exchange regulatory factor-1 (NHERF1) complexes to the actin cytoskeleton, thereby averting the rapid internalization of this channel variant. However, the molecular basis for why rPhe508del fails to recruit active EZR to the PM remains elusive. Here, using a proteomics approach, we characterized and compared the core components of wt-CFTR– or rPhe508del–containing macromolecular complexes at the surface of human bronchial epithelial cells. We identified calpain 1 (CAPN1) as an exclusive rPhe508del interactor that prevents active EZR recruitment, impairs rPhe508del anchoring to actin, and reduces its stability in the PM. We show that either CAPN1 downregulation or its chemical inhibition dramatically improves the functional rescue of Phe508del-CFTR in airway cells. These observations suggest that CAPN1 constitutes an attractive target for pharmacological intervention, as part of CF combination therapies restoring Phe508del-CFTR function.This work was supported by a center grant UID/MULTI/04046/2019 to BioISI and project PTDC/BIA-CEL/28408/2017 and IF2012 to PM, both from FCT, Portugal. AMM was recipient of fellowship SFRH/BD/52490/2014 from BioSYS PhD programme PD65-2012, and PB of fellowship SFRH/BPD/94322/2013.N/

Entangled coherent states and squeezing in N trapped ions

We consider a resonant bichromatic excitation of N trapped ions that generates displacement and squeezing in their collective motion conditioned to their ionic internal state, producing eventually Scrhodinger cat states and entangled squeezing. Furthermore, we study the case of tetrachromatic illumination or producing the so called entangled coherent states in two motional normal modes.Comment: 4 Revtex pages, no figures. To appear in Proceedings of "Mysteries, Puzzles and Paradoxes in Quantum Mechanics", Garda Lake, Italy (2001

Inflation from IIB Superstrings with Fluxes

We study the conditions needed to have an early epoch of inflationary expansion with a potential coming from IIB superstring theory with fluxes involving two moduli fields. The phenomenology of this potential is different from the usual hybrid inflation scenario and we analize the possibility that the system of field equations undergo a period of inflation in three different regimes with the dynamics modified by a Randall-Sundrum II term in the Friedmann equation. We find that the system can produce inflation and due to the modification of the dynamics, a period of accelerated contraction can follow or preceed this inflationary stage depending on the sign of one of the parameters of the potential. We discuss on the viability of this model in a cosmological context.Comment: 10 pages, 6 figure

Identification of a spatio-temporal model of crystal growth based on boundary curvature

A new method of identifying the spatio-temporal transition rule of crystal growth is introduced based on the connection between growth kinetics and dentritic morphology. Using a modified three-point-method, curvatures of the considered crystal branch are calculated and curvature direction is used to measure growth velocity. A polynomial model is then produced based on a curvature-velocity relationship to represent the spatio-temporal growth process. A very simple simulation example is used initially to clearly explain the methodology. The results of identifying a model from a real crystal growth experiment show that the proposed method can produce a good representation of crystal growth

Oscillatons revisited

In this paper, we study some interesting properties of a spherically symmetric oscillating soliton star made of a real time-dependent scalar field which is called an oscillaton. The known final configuration of an oscillaton consists of a stationary stage in which the scalar field and the metric coefficients oscillate in time if the scalar potential is quadratic. The differential equations that arise in the simplest approximation, that of coherent scalar oscillations, are presented for a quadratic scalar potential. This allows us to take a closer look at the interesting properties of these oscillating objects. The leading terms of the solutions considering a quartic and a cosh scalar potentials are worked in the so called stationary limit procedure. This procedure reveals the form in which oscillatons and boson stars may be related and useful information about oscillatons is obtained from the known results of boson stars. Oscillatons could compete with boson stars as interesting astrophysical objects, since they would be predicted by scalar field dark matter models.Comment: 10 pages REVTeX, 10 eps figures. Updated files to match version published in Classical and Quantum Gravit

Analysis of process variables via CFD to evaluate the performance of a FCC riser

Feedstock conversion and yield products are studied through a 3D model simulating the main reactor of the fluid catalytic cracking (FCC) process. Computational fluid dynamic (CFD) is used with Eulerian-Eulerian approach to predict the fluid catalytic cracking behavior. The model considers 12 lumps with catalyst deactivation by coke and poisoning by alkaline nitrides and polycyclic aromatic adsorption to estimate the kinetic behavior which, starting from a given feedstock, produces several cracking products. Different feedstock compositions are considered. The model is compared with sampling data at industrial operation conditions. The simulation model is able to represent accurately the products behavior for the different operating conditions considered. All the conditions considered were solved using a solver ANSYS CFX 14.0. The different operation process variables and hydrodynamic effects of the industrial riser of a fluid catalytic cracking (FCC) are evaluated. Predictions from the model are shown and comparison with experimental conversion and yields products are presented; recommendations are drawn to establish the conditions to obtain higher product yields in the industrial process

Quantum speed limit for physical processes

The evaluation of the minimal evolution time between two distinguishable states of a system is important for assessing the maximal speed of quantum computers and communication channels. Lower bounds for this minimal time have been proposed for unitary dynamics. Here we show that it is possible to extend this concept to nonunitary processes, using an attainable lower bound that is connected to the quantum Fisher information for time estimation. This result is used to delimit the minimal evolution time for typical noisy channels.Comment: results unchanged; new in this version: greater focus on geometrical interpretation of results, added references, improvements in style, comments on exclusion window left mainly for the supplemental material; main article: 7 pages (including references), 2 figures; supplemental material: 5 pages, 4 figure