Trisections of a 3-rotationally symmetric planar convex body minimizing the maximum relative diameter

In this work we study the fencing problem consisting of finnding a trisection of a 3-rotationally symmetric planar convex body which minimizes the maximum relative diameter. We prove that an optimal solution is given by the so-called standard trisection. We also determine the optimal set giving the minimum value for this functional and study the corresponding universal lower bound.Comment: Preliminary version, 20 pages, 15 figure

Returns-Driven Macro Regimes and Characteristic Lead-Lag Behaviour between Asset Classes

We define data-driven macroeconomic regimes by clustering the relative performance in time of indices belonging to different asset classes. We then investigate lead-lag relationships within the regimes identified. Our study unravels market features characteristic of different windows in time and leverages on this knowledge to highlight market trends or risks that can be informative with respect to recurrent market developments. The framework developed also lays the foundations for multiple possible extensions.Comment: 9 pages, 8 figure

SEC Form 13F-HR: Statistical investigation of trading imbalances and profitability analysis

US Institutions with more than $100 million assets under management must disclose part of their long positions into the SEC Form 13F-HR on a quarterly basis. We consider the number of variations in holdings between consecutive reporting periods, and compute imbalances in buying versus selling behaviour for the assets under consideration. A significant opportunity for profit arises if an external investor is willing to trade contrarian to the 13F filings imbalances. Indeed, imbalances capture the amount of information already consumed in the market and the related trades tend to be inflated by crowding and herding. Betting on a relatively short-term movement of prices against the sign of imbalances results in a profitable strategy especially when using a time horizon between 21 and 42 trading days (corresponding to 1-2 calendar months) after each financial quarter ends.Comment: 23 pages, 18 figure

Study of the root dentin permeability of primary teeth. Cleansers and irrigation method evaluation

Orientador: Regina Maria Puppin-RontaniDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: Um dos principais objetivos do tratamento endodôntico é o debridamento do sistema de canais radiculares através da remoção dos restos pulpares, da smear layer e smear plugs, para eliminar a contaminação bacteriana e subprodutos da mesma, os quais podem se tornar reservatórios de irritantes no canal tratado. Além disso, as substâncias irrigadoras e os métodos de irrigação utilizados durante o preparo químico-mecânico, podem também contribuir para a remoção da smear layer e consequentemente alterar a permeabilidade dentinária. Dessa forma, os objetivos desta Dissertação foram: (1) discutir através da revisão da literatura, a eficácia de substâncias irrigadoras, bem como a influência de dois métodos de irrigação (irrigação manual ou ativação ultrasônica) utilizados durante o preparo químico-mecânico de dentes decíduos e permanentes, considerando a permeabilidade da dentina radicular; (2) correlacionar o índice de permeabilidade da dentina radicular de dentes decíduos sob a influência de substâncias irrigadoras associadas ou não a auxiliares de instrumentação (líquido de Dakin, líquido de Dakin associado ao peróxido de hidrogênio, solução salina associada à clorexidina gel e solução salina) e diferentes métodos de irrigação (irrigação manual ou ativação ultrasônica) aos seus aspectos morfológicos (presença ou ausência de smear layer). Baseando-se na revisão de literatura pôde-se concluir que as substâncias irrigadoras e associações utilizadas durante o tratamento endodôntico promoveram aumento da permeabilidade dentinária radicular de dentes permanentes e que não houve diferenças quanto à permeabilidade dentinária, quando comparada a irrigação realizada manualmente ou através de vibração ultrasônica. Não há estudos relacionados à permeabilidade radicular de dentes decíduos, quando estes são submetidos a substâncias irrigadoras e diferentes métodos de irrigação. A técnica de irrigação manual foi considerada mais efetiva do que a técnica de irrigação através de sistema de vibração ultrasônica, quanto à permeabilidade dentinária radicular de dentes decíduos. A presença da smear layer nas paredes radiculares foi um fator limitante à penetração do corante (índice de permeabilidade) para o terço médio quando dentes decíduos foram irrigados manualmente. O líquido de Dakin apresentou os maiores valores de índice de permeabilidade, nos três terços radiculares, sugerindo que essa solução irrigadora seja indicada para o tratamento endodôntico de dentes decíduos.Abstract: One of the main goals of root canal treatment is the cleaning of the entire root canal system, through removal of pulpal debris, smear layer and smear plugs in order to avoid harbor bacteria or bacterial by-products, providing a reservoir of potential irritants in treated root canal. In addition, the cleansers and irrigation methods used in the endodontic treatment, can also contribute with the smear layer removal and with permeability alterations. Thus, the aims of this Thesis was: (1) to discuss the efficacy of some cleansers, as well as the influence of two irrigation systems used during endodontic preparation of primary and permanent teeth (manual or ultrasonic vibration) with regard to root dentin permeability, based on a literature reviewing; (2) to correlate the dye permeability to morphological aspect (presence or absence of smear layer) of the primary root dentin wall, using scanning electron microscopy (SEM), regarding the endodontic preparation and irrigation methods. Based on literature review (1) it can be concluded that among the solutions used for permanent teeth, all solutions and associations studied increased the dentin permeability. There was no difference in the dentin permeability when comparing manual and ultrasonic irrigation. There are not enough papers focusing primary teeth on this subject to definitely establish the patterns of increased dentin permeability in tooth root canal treatment regarding the irrigating solutions and irrigation systems. The results of the second study showed that manual irrigation technique was better than ultrasonic one and that Dakin's liquid, Dakin's liquid associated with hydrogen peroxide, and saline solution showed the highest permeability index averages values. Regarding the correlation study, it could be concluded that the smear layer presence on the root dentin walls was a limiting factor to dye penetration (Permeability Index), in middle third for manual irrigation.MestradoOdontopediatriaMestre em Odontologi

What’s going on in my city? Recommender systems and electronic participatory budgeting

In this paper, we present electronic participatory budgeting (ePB) as a novel application domain for recommender systems. On public data from the ePB platforms of three major US cities – Cambridge, Miami and New York City–, we evaluate various methods that exploit heterogeneous sources and models of user preferences to provide personalized recommendations of citizen proposals. We show that depending on characteristics of the cities and their participatory processes, particular methods are more effective than others for each city. This result, together with open issues identified in the paper, call for further research in the area

Emotional factors and mathematics: the role of maths anxiety and math-self perceptions in primary school children

openLa ricerca ha l'obiettivo di indagare l'apprendimento matematico e gli aspetti emotivi legati alla materia. Si analizza la relazione esistente tra ansia per la matematica, percezione di autoefficacia matematica, percezione di competenza e prestazione matematica

Japanese syntactic structures and their constructional meanings

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Linguistics and Philosophy, 1992.Includes bibliographical references (leaves 247-254).by Miori Kubo.Ph.D

On relative isodiametric inequalities

We consider subdivisions of convex bodies G in two subsets E and G\E. We obtain several inequalities comparing the relative volume 1) with the minimum relative diameter and 2) with the maximum relative diameter. In the second case we obtain the best upper estimate only for subdivisions determined by straight lines in planar sets

Gender Differences In Academic Ethics With Recommendations For Curricular Change

An extensive study has been performed on the importance of building ethical principles into secondary school and college curricula.  In published surveys, females are almost universally found to be more ethical, but experience tells us females lag behind males in their ability to maintain and act upon their convictions in the workplace.  We examined these issues by administering a survey on academic ethics to an undergraduate business school population, focusing heavily on gender differences. Careful analysis of survey results using one-way ANOVA, the Tukey-Kramer procedure, and two-way ANOVA procedures provided an understanding of differences in ethical beliefs and ethical behaviors based on gender and other demographic characterizations.  Predictive analysis was completed using logistic regression and discrete choice modeling to determine the likelihood of ethical behavior in the future and evolution of ethical beliefs.  The accumulated results of the analyses were used to guide the authors in the development of a strong and pervasive ethics-based curriculum for secondary schools and universities.  We have combined elements of classroom instruction, technology, active learning, games and extracurricular activities to embed ethical concepts and particularly encourage strength in convictions across the entire curricula.