Aixecament topogràfic en tres dimensions de l'Arborètum Dr. Pius Font i Quer de Lleida

Amb el nou jardí botànic de Lleida, l’Arborètum, s’ha aconseguit un gran jardí botànic amb gran variabilitat d’espècies, ja que en 7ha de terreny hi podem trobar fins a 16 ambients amb diferents biodiversitats. En total hi ha uns 1.500 arbres de 225 espècies diferents i 90.000 arbustos de 300 espècies repartits en el territori. Tenint en compte la importància d’aquest jardí botànic, i relacionant-lo amb la topografia, volem aconseguir veure’l en tres dimensions. A través de la visió 3D intentarem donar un tomb virtual dins d’aquest Arborètum, intentant plasmar amb exactitud el seu relleu i recorregut, així com cada un dels seus biomes.

Noves i velles migracions: dimensions de la integració sociocultural dels immigrants a Lleida

En aquest article sobre Noves i velles migracions: dimensions de la integració sociocultural dels immigrants a Lleida (1999), s'analitza de forma concisa aquest fenòmen per identificar les principals característiques diferenciadores dels immigrants de la zona lleidatana. L'article consta de tres apartats. En el primer, la introducció, es resumeixen breument els continguts del treball que donen títol a l'article. El segon apartat tracta sobre la integració dels immigrants i comença per una breu reflexió sobre els canvis d'enfocament a l'hora d'estudiar el fenòmen migratori que ajuda a entendre, per exemple, perquè avui parlem d'integració i no d'assimilació. Posteriorment, s'analitza el model migratori català del qual destaca la inexistència de fractura social malgrat l'elevada arribada d'immigrants a Catalunya, i valora els diferents nivells d'integració assolida en cada onada immigratòria del segle XX. Finalment, es detallen els diferents factors relacionats amb la integració sociocultural (impacte en el creixement demogràfic, sistema educatiu, integració en el mercat laboral i adopció de la llengua catalana) de la població immigrada a la ciutat de Lleida i comarques. El treball conclou que el repte és trobar el model d'integració sociocultural adient per al col•lectiu extracomunitari que integra, majoritàriament, l'onada migratòria iniciada en la dècada dels noranta.

Dilaton quantum cosmology in two dimensions

We consider a renormalizable two-dimensional model of dilaton gravity coupled to a set of conformal fields as a toy model for quantum cosmology. We discuss the cosmological solutions of the model and study the effect of including the back reaction due to quantum corrections. As a result, when the matter density is below some threshold new singularities form in a weak-coupling region, which suggests that they will not be removed in the full quantum theory. We also solve the Wheeler-DeWitt equation. Depending on the quantum state of the Universe, the singularities may appear in a quantum region where the wave function is not oscillatory, i.e., when there is not a well-defined notion of classical spacetime.

Energy-momentum tensor for scalar fields coupled to the dilaton in two dimensions

We clarify some issues related to the evaluation of the mean value of the energy-momentum tensor for quantum scalar fields coupled to the dilaton field in two-dimensional gravity. Because of this coupling, the energy-momentum tensor for matter is not conserved and therefore it is not determined by the trace anomaly. We discuss different approximations for the calculation of the energy-momentum tensor and show how to obtain the correct amount of Hawking radiation. We also compute cosmological particle creation and quantum corrections to the Newtonian potential.

Multislice CT for assessing in-stent dimensions after left main coronary artery stenting: a comparison with three dimensional intravascular ultrasound

Objective: To evaluate the agreement between multislice CT (MSCT) and intravascular ultrasound (IVUS) to assess the in-stent lumen diameters and lumen areas of left main coronary artery (LMCA) stents. Design: Prospective, observational single centre study. Setting: A single tertiary referral centre. Patients: Consecutive patients with LMCA stenting excluding patients with atrial fibrillation and chronic renal failure. Interventions: MSCT and IVUS imaging at 9-12 months follow-up were performed for all patients. Main outcome measures: Agreement between MSCT and IVUS minimum luminal area (MLA) and minimum luminal diameter (MLD). A receiver operating characteristic (ROC) curve was plotted to find the MSCT cut-off point to diagnose binary restenosis equivalent to 6 mm2 by IVUS. Results: 52 patients were analysed. Passing-Bablok regression analysis obtained a β coefficient of 0.786 (0.586 to 1.071) for MLA and 1.250 (0.936 to 1.667) for MLD, ruling out proportional bias. The α coefficient was −3.588 (−8.686 to −0.178) for MLA and −1.713 (−3.583 to −0.257) for MLD, indicating an underestimation trend of MSCT. The ROC curve identified an MLA ≤4.7 mm2 as the best threshold to assess in-stent restenosis by MSCT. Conclusions: Agreement between MSCT and IVUS to assess in-stent MLA and MLD for LMCA stenting is good. An MLA of 4.7 mm2 by MSCT is the best threshold to assess binary restenosis. MSCT imaging can be considered in selected patients to assess LMCA in-stent restenosis

Lower incisor dentoalveolar compensation and symphysis dimensions among Class I and III malocclusion patients with different facial vertical skeletal patterns

Objective: To compare lower incisor dentoalveolar compensation and mandible symphysis morphology among Class I and Class III malocclusion patients with different facial vertical skeletal patterns. Materials and Methods: Lower incisor extrusion and inclination, as well as buccal (LA) and lingual (LP) cortex depth, and mandibular symphysis height (LH) were measured in 107 lateral cephalometric x-rays of adult patients without prior orthodontic treatment. In addition, malocclusion type (Class I or III) and facial vertical skeletal pattern were considered. Through a principal component analysis (PCA) related variables were reduced. Simple regression equation and multivariate analyses of variance were also used. Results: Incisor mandibular plane angle (P < .001) and extrusion (P  =  .03) values showed significant differences between the sagittal malocclusion groups. Variations in the mandibular plane have a negative correlation with LA (Class I P  =  .03 and Class III P  =  .01) and a positive correlation with LH (Class I P  =  .01 and Class III P  =  .02) in both groups. Within the Class III group, there was a negative correlation between the mandibular plane and LP (P  =  .02). PCA showed that the tendency toward a long face causes the symphysis to elongate and narrow. In Class III, alveolar narrowing is also found in normal faces. Conclusions: Vertical facial pattern is a significant factor in mandibular symphysis alveolar morphology and lower incisor positioning, both for Class I and Class III patients. Short-faced Class III patients have a widened alveolar bone. However, for long-faced and normal-faced Class III, natural compensation elongates the symphysis and influences lower incisor position.