Oval Domes: History, Geometry and Mechanics

An oval dome may be defined as a dome whose plan or profile (or both) has an oval form. The word Aoval@ comes from the latin Aovum@, egg. Then, an oval dome has an egg-shaped geometry. The first buildings with oval plans were built without a predetermined form, just trying to close an space in the most economical form. Eventually, the geometry was defined by using arcs of circle with common tangents in the points of change of curvature. Later the oval acquired a more regular form with two axis of symmetry. Therefore, an “oval” may be defined as an egg-shaped form, doubly symmetric, constructed with arcs of circle; an oval needs a minimum of four centres, but it is possible also to build polycentric ovals. The above definition corresponds with the origin and the use of oval forms in building and may be applied without problem until, say, the XVIIIth century. Since then, the teaching of conics in the elementary courses of geometry made the cultivated people to define the oval as an approximation to the ellipse, an “imperfect ellipse”: an oval was, then, a curve formed with arcs of circles which tries to approximate to the ellipse of the same axes. As we shall see, the ellipse has very rarely been used in building. Finally, in modern geometrical textbooks an oval is defined as a smooth closed convex curve, a more general definition which embraces the two previous, but which is of no particular use in the study of the employment of oval forms in building. The present paper contains the following parts: 1) an outline the origin and application of the oval in historical architecture; 2) a discussion of the spatial geometry of oval domes, i. e., the different methods employed to trace them; 3) a brief exposition of the mechanics of oval arches and domes; and 4) a final discussion of the role of Geometry in oval arch and dome design

Conociendo y comprendiendo interacciones entre pares que generan dinámicas agresivas entre estudiantes de primero a quinto de básica primaria del instituto Rafael Núñez de la sede del barrio porfía, 2012

En la vida moderna se vive a un ritmo en el cual las relaciones afectivas se deterioran cada vez más, y la comunidad escolar por supuesto no escapa de ella; por ello el propósito de esta propuesta se efectúo con el fin de comprender las dinámicas que se presentan entre los estudiantes del plantel educativo Rafael Núñez, en el cual se observó mediante algunas visitas que los niño(a)s interactúan agresivamente. Para esta propuesta, se eligió como muestra un grupo de 60 estudiantes de básica primaria con edades entre los 6 a 13 años de la comunidad estudiantil Rafael Núñez, donde se evidenció que éste establecimiento, no es ajeno al fenómeno de las interacciones agresivas en el momento de realizar algunas acciones comunicativas entre pares; algunas de ellas se encuentran frente al entorno educativo de forma verbal o física y otras no, manteniendo así un bajo perfil no por esto menos impactantes; en muchas ocasiones estas presiones se presentan de manera grupal y acaban por coaccionar al más débil de la relación, generando un conflicto e imposibilitando de este modo establecer relaciones adecuadas entre los estudiantes. Este estudio se efectúa ya que los problemas de manifestaciones agresivas en niños, han sido motivo de estudio desde diversos contextos (legal, social, educativo y médico), y en distintas partes del mundo, por sus graves consecuencias en la formación integral del niño y en su personalidad futura como adulto. Con el propósito de acompañar a la comunidad educativa mediante el desarrollo de estrategias psicosociales, para estimular relaciones solidarias, pacificas y afectuosas, surgieron alternativas de desarrollo de habilidades individuales e inter-grupales en las aulas escolares, logrando mejorar con esto prácticas de comunicación humana, las relaciones consigo mismo, con los demás, con el entorno, en donde se da un abordaje de conflictos a fin de mejorar el clima escolar y transformar la cultura institucional, para lo cual se usó el desarrollo de las temáticas: habilidades sociales, relaciones humanas, comunicación humana y abordaje de conflictos.In modern life is lived at a pace which affective relations deteriorate more and more, and the school community of course not escape from it, hence the purpose of this proposal was made to understand the dynamics present among students of campus Rafael Nunez, which was observed by several visits to the child’s interact aggressively. For this proposal, was chosen as a sample group of 60 primary school students aged 6 to 13 years of the student community Rafael Nunez, where it was shown that this facility is no stranger to the phenomenon of aggressive interactions at the time to perform some communicative actions between pairs, some of them are facing the educational environment of verbal or physical and not others, thus maintaining a low profile is no less impressive, in many cases, these pressures are presented in groups and eventually coerce the weaker the relationship, creating a conflict and thus impossible to establish appropriate relationships with students. This study was done because the problems of aggressive manifestations in children, have been studied from different contexts (legal, social, educational and medical), and in different parts of the world for its serious consequences in the integral formation of children and in its future as an adult personality. In order to accompany the educational community through the development of psychosocial strategies to encourage supportive relationships, peaceful and loving, there were alternatives to develop individual skills and inter-group in the classroom, getting better with this practice of human communication, relationships with self, others, with the environment, where there is a conflict management to improve school climate and transform the institutional culture, which was used for the development of themes: social skills, human relations , human communication and conflict management

Charge separation relative to the reaction plane in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}}= 2.76 TeV

Measurements of charge dependent azimuthal correlations with the ALICE detector at the LHC are reported for Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 2.76$ TeV. Two- and three-particle charge-dependent azimuthal correlations in the pseudo-rapidity range $|\eta| < 0.8$ are presented as a function of the collision centrality, particle separation in pseudo-rapidity, and transverse momentum. A clear signal compatible with a charge-dependent separation relative to the reaction plane is observed, which shows little or no collision energy dependence when compared to measurements at RHIC energies. This provides a new insight for understanding the nature of the charge dependent azimuthal correlations observed at RHIC and LHC energies.Comment: 12 pages, 3 captioned figures, authors from page 2 to 6, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/286

Multi-particle azimuthal correlations in p-Pb and Pb-Pb collisions at the CERN Large Hadron Collider

Measurements of multi-particle azimuthal correlations (cumulants) for charged particles in p-Pb and Pb-Pb collisions are presented. They help address the question of whether there is evidence for global, flow-like, azimuthal correlations in the p-Pb system. Comparisons are made to measurements from the larger Pb-Pb system, where such evidence is established. In particular, the second harmonic two-particle cumulants are found to decrease with multiplicity, characteristic of a dominance of few-particle correlations in p-Pb collisions. However, when a $|\Delta \eta|$ gap is placed to suppress such correlations, the two-particle cumulants begin to rise at high-multiplicity, indicating the presence of global azimuthal correlations. The Pb-Pb values are higher than the p-Pb values at similar multiplicities. In both systems, the second harmonic four-particle cumulants exhibit a transition from positive to negative values when the multiplicity increases. The negative values allow for a measurement of $v_{2}\{4\}$ to be made, which is found to be higher in Pb-Pb collisions at similar multiplicities. The second harmonic six-particle cumulants are also found to be higher in Pb-Pb collisions. In Pb-Pb collisions, we generally find $v_{2}\{4\} \simeq v_{2}\{6\}\neq 0$ which is indicative of a Bessel-Gaussian function for the $v_{2}$ distribution. For very high-multiplicity Pb-Pb collisions, we observe that the four- and six-particle cumulants become consistent with 0. Finally, third harmonic two-particle cumulants in p-Pb and Pb-Pb are measured. These are found to be similar for overlapping multiplicities, when a $|\Delta\eta| > 1.4$ gap is placed.Comment: 25 pages, 11 captioned figures, 3 tables, authors from page 20, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/87

A note on comonotonicity and positivity of the control components of decoupled quadratic FBSDE

In this small note we are concerned with the solution of Forward-Backward Stochastic Differential Equations (FBSDE) with drivers that grow quadratically in the control component (quadratic growth FBSDE or qgFBSDE). The main theorem is a comparison result that allows comparing componentwise the signs of the control processes of two different qgFBSDE. As a byproduct one obtains conditions that allow establishing the positivity of the control process.Comment: accepted for publicatio

Multiplicity dependence of jet-like two-particle correlations in p-Pb collisions at sNN\sqrt{s_{NN}} = 5.02 TeV

Two-particle angular correlations between unidentified charged trigger and associated particles are measured by the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV. The transverse-momentum range 0.7 $< p_{\rm{T}, assoc} < p_{\rm{T}, trig} <$ 5.0 GeV/$c$ is examined, to include correlations induced by jets originating from low momen\-tum-transfer scatterings (minijets). The correlations expressed as associated yield per trigger particle are obtained in the pseudorapidity range $|\eta|<0.9$. The near-side long-range pseudorapidity correlations observed in high-multiplicity p-Pb collisions are subtracted from both near-side short-range and away-side correlations in order to remove the non-jet-like components. The yields in the jet-like peaks are found to be invariant with event multiplicity with the exception of events with low multiplicity. This invariance is consistent with the particles being produced via the incoherent fragmentation of multiple parton--parton scatterings, while the yield related to the previously observed ridge structures is not jet-related. The number of uncorrelated sources of particle production is found to increase linearly with multiplicity, suggesting no saturation of the number of multi-parton interactions even in the highest multiplicity p-Pb collisions. Further, the number scales in the intermediate multiplicity region with the number of binary nucleon-nucleon collisions estimated with a Glauber Monte-Carlo simulation.Comment: 23 pages, 6 captioned figures, 1 table, authors from page 17, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/161

Transverse sphericity of primary charged particles in minimum bias proton-proton collisions at s=0.9\sqrt{s}=0.9, 2.76 and 7 TeV

Measurements of the sphericity of primary charged particles in minimum bias proton--proton collisions at $\sqrt{s}=0.9$, 2.76 and 7 TeV with the ALICE detector at the LHC are presented. The observable is linearized to be collinear safe and is measured in the plane perpendicular to the beam direction using primary charged tracks with $p_{\rm T}\geq0.5$ GeV/c in $|\eta|\leq0.8$. The mean sphericity as a function of the charged particle multiplicity at mid-rapidity ($N_{\rm ch}$) is reported for events with different $p_{\rm T}$ scales ("soft" and "hard") defined by the transverse momentum of the leading particle. In addition, the mean charged particle transverse momentum versus multiplicity is presented for the different event classes, and the sphericity distributions in bins of multiplicity are presented. The data are compared with calculations of standard Monte Carlo event generators. The transverse sphericity is found to grow with multiplicity at all collision energies, with a steeper rise at low $N_{\rm ch}$, whereas the event generators show the opposite tendency. The combined study of the sphericity and the mean $p_{\rm T}$ with multiplicity indicates that most of the tested event generators produce events with higher multiplicity by generating more back-to-back jets resulting in decreased sphericity (and isotropy). The PYTHIA6 generator with tune PERUGIA-2011 exhibits a noticeable improvement in describing the data, compared to the other tested generators.Comment: 21 pages, 9 captioned figures, 3 tables, authors from page 16, published version, figures from http://aliceinfo.cern.ch/ArtSubmission/node/308

Centrality dependence of charged particle production at large transverse momentum in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm{NN}}} = 2.76 TeV

The inclusive transverse momentum ($p_{\rm T}$) distributions of primary charged particles are measured in the pseudo-rapidity range $|\eta|<0.8$ as a function of event centrality in Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}=2.76$ TeV with ALICE at the LHC. The data are presented in the $p_{\rm T}$ range $0.15<p_{\rm T}<50$ GeV/$c$ for nine centrality intervals from 70-80% to 0-5%. The Pb-Pb spectra are presented in terms of the nuclear modification factor $R_{\rm{AA}}$ using a pp reference spectrum measured at the same collision energy. We observe that the suppression of high-$p_{\rm T}$ particles strongly depends on event centrality. In central collisions (0-5%) the yield is most suppressed with $R_{\rm{AA}}\approx0.13$ at $p_{\rm T}=6$-7 GeV/$c$. Above $p_{\rm T}=7$ GeV/$c$, there is a significant rise in the nuclear modification factor, which reaches $R_{\rm{AA}} \approx0.4$ for $p_{\rm T}>30$ GeV/$c$. In peripheral collisions (70-80%), the suppression is weaker with $R_{\rm{AA}} \approx 0.7$ almost independently of $p_{\rm T}$. The measured nuclear modification factors are compared to other measurements and model calculations.Comment: 17 pages, 4 captioned figures, 2 tables, authors from page 12, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/284

Serum levels of S-100 protein are directly proportional to the size, number, thickness and degree of cellularity of congenital melanocytic nevi

To the Editor: Some patients with congenital melanocytic nevi (CMN) present progressive growth and thickening, extracutaneous involvement (neurocutaneous melanocytosis, NCM) or neoplastic transformation (melanoma); and others remain stable or even regress. There are no markers to assess progression or follow-up. Recently, we found S-100, a protein which acts on cell differentiation and proliferation, elevated in CMN.1 S-100 is a ligand of the RAGE pathway (related to the MAPK-pathway), and low serum levels of soluble-RAGE were related to poor survival in melanoma.2 Also SOX10, expressed in melanocytes with high specificity, is useful in detection, prognosis and treatment assessment of melanoma.3 We explored if S-100, RAGE and SOX10 serum levels vary in children’s CMN and assessed clinical or pathological correlations