Ratchet universality in the bidirectional escape from a symmetric potential well

The present work discusses symmetry-breaking-induced bidirectional escape from a symmetric metastable potential well by the application of zero-average periodic forces in the presence of dissipation. We characterized the interplay between heteroclinic instabilities leading to chaotic escape and breaking of a generalized parity symmetry leading to directed ratchet escape to an attractor either at infinity or at -infinity. Optimal enhancement of directed ratchet escape is found to occur when the wave form of the zero-average periodic force acting on the damped driven oscillator matches as closely as possible to a universal wave form, as predicted by the theory of ratchet universality. Specifically, the optimal approximation to the universal force triggers the almost complete destruction of the nonescaping basin for driving amplitudes which are systematically lower than those corresponding to a symmetric periodic force having the same period. We expect that this work could be potentially useful in the control of elementary dynamic processes characterized by multidirectional escape from a potential well, such as forced chaotic scattering and laser-induced dissociation of molecular systems, among others

From Declarative Set Constraint Models to “Good” SAT Instances

On the one hand, Constraint Satisfaction Problems allow one to declaratively model problems. On the other hand, propositional satisfiability problem (SAT) solvers can handle huge SAT instances. We thus present a technique to declaratively model set constraint problems, to reduce them, and to encode them into ”good” SAT instances. We illustrate our technique on the well-known nqueens problem. Our technique is simpler, more expressive, and less error-prone than direct hand modeling. The SAT instances that we automatically generate are rather small w.r.t. hand-written instances

Sex-specific behavioral and neurogenic responses to cocaine in mice lacking and blocking dopamine D1 or dopamine D2 receptors

Adult neurogenesis in rodents is modulated by dopaminergic signaling and inhibited by cocaine. However, the sex-specific role of dopamine D1 and D2 receptors (D1R, D2R) in the deleterious effect of cocaine on adult neurogenesis has not been described yet. Here, we explored sex differences in (a) cell proliferation (5′-bromo-2′-deoxyuridine [BrdU]), (b) neural precursor (nestin), (c) neuronal phenotype (BrdU/β3-tubulin), and (d) neuronal maturity (NeuN) in the subventricular zone (SVZ) of the lateral ventricles and striatum of mice with genetic deletion (D1, D2) or pharmacological blockage (SCH23390: 0.1 mg/kg/day/5 days; Raclopride: 0.3 mg/kg/day/5 days) of D1R and D2R, and treated (10 mg/kg/day/5 days) and then challenged (5 mg/kg, 48 hr later) with cocaine. Results indicated that hyperactivity responses to cocaine were absent in D1 mice and reduced in SCH23390-treated mice. Activity responses to cocaine were reduced in D2 males, but absent in D2 females and increased in Raclopride-treated females. D1R deletion blocked the deleterious effect of cocaine on SVZ cell proliferation in males. Cocaine-exposed D1 males also had reduced neuronal phenotype of SVZ newborn cells and increased striatal neuronal maturity. D2 mice had lower proliferative and neural precursor responses. Cocaine in D2 females or coadministered with Raclopride in wild-type females improved SVZ cell proliferation, an effect that positively correlated with plasma brain-derived neurotrophic factor (BDNF) concentrations. In conclusion, the sex-specific D1R and D2R signaling on SVZ cell proliferation, neural progenitor and neuronal maturity is differentially perturbed by cocaine, and BDNF may be required to link D2R to neuroplasticity in cocaine addiction in females.Consejería de Salud, Junta de Andalucía, Grant/Award Number: C1-0049-2019; Instituto de Salud Carlos III, Grant/Award Numbers: CP19/00068, CPII17/00024, CPII19/00022, CPII19/00031, PI19/01577, PI19/00886, PI17/02026, RD16/0017/0001; Ministerio de Sanidad, Servicios Sociales e Igualdad, Grant/Award Numbers: PND2017/043, PND2018/033, PND2018/044, PND2019/04

Psychometric characteristics of a commuting-to-school behaviour questionnaire for families

The purposes of this study were: (a) to describe the patterns of modes of commuting to school (children) and to work (parents) separated by gender and age, (b) to validate the questions on children’s mode of commuting to and from school according to their parents, and (c) to analyse the reliability of a family questionnaire focused on commuting to school behaviours. A total of 611 parents (mean age: 43.28 ± 6.25 years old) from Granada (Spain) completed “Family commuting-to-school behaviour” questionnaire in two sessions separated by 14 days, (2016 and 2018). The validation between family and children’s questions was assessed using the Kappa and Spearman correlation coefficients, and the test–retest reliability within the family questions was assessed using the Kappa and the weighted Kappa. The children’s modes of commuting to school (mean age: 11.44 ± 2.77 years old) were mainly passive (57.7% to school) while parents’ modes of commuting to work were mainly active (71.6%). The validity of the mode of commuting was significant with high Kappa and Spearman coefficients. The test–retest reliability presented a good agreement for the mode of commuting to school in children, distance and time to school, and the mode of commuting to work in parents, while the questions on acceptable distance to walk or cycle to school showed a moderate to good agreement. The “Family commuting-to-school behaviour” questionnaire could be a useful tool to assess the mode of commuting of children, distance and time to school for researchers and practitioners

Correction to: A Phase II Study Evaluating Combined Neoadjuvant Cetuximab and Chemotherapy Followed by Chemoradiotherapy and Concomitant Cetuximab in Locoregional Oesophageal Cancer Patients

Errors were subsequently identified in the article and the following corrections should be note

Un nuevo grupo de manos paleolíticas pintadas en el sur de la Península Ibérica. La cueva de las Estrellas (Castellar de la Frontera, Cádiz)

Presentamos en este trabajo la revisión de las manifestaciones de arte rupestre conservadas en una estación localizada en la comunidad autónoma de Andalucía, conocida en la literatura precedente como cueva de Las Estrellas (Castellar de la Frontera, Cádiz). Se trata de un abrigo rocoso de grandes dimensiones, abierto al aire libre, en el que ya se había constatado, en los primeros años del presente siglo, la presencia de diversas pictografías de estilo esquemático. Durante una visita reciente al enclave se ha advertido, además, la existencia de un importante conjunto figurativo de cronología paleolítica que incluye representaciones de fauna y una pequeña serie de improntas de manos en negativo. Este artículo aborda el análisis genérico de las grafías catalogadas hasta el momento en la cavidad, atendiendo con especial detalle al conjunto de las citadas huellas de manos paleolíticas, que han sido documentadas usando tecnología digital 3d. De igual modo, se tendrán en cuenta su contextualización en el arte paleolítico andaluz y una primera aproximación cronológica a este interesante y variado complejo figurativo

Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02