GeoGebra e iTALC numa abordagem criativa das isometrias

Mestrado em DidácticaA criatividade é reconhecida, nos dias de hoje, como uma competência essencial ao desenvolvimento dos povos. Neste contexto, a sociedade carece de um modelo de Escola que seja capaz de promover o desenvolvimento da criatividade nos seus alunos, resgatando-os da inevitabilidade de desempenharem um papel secundário no palco da economia global. No entanto, a Escola não tem sabido, querido ou conseguido potenciar este desenvolvimento, cerceando o seu potencial criativo. Por outro lado, emerge, das diferentes reformas e programas curriculares, um reconhecimento crescente da importância da Geometria, não só no âmbito da Matemática, mas também ao nível da formação global dos indivíduos. A renovação conceptual verificada em alguns tópicos, nomeadamente, nas isometrias, conjugada com as mais recentes orientações internacionais para o seu ensino e aprendizagem exige novas abordagens na sala de aula baseadas em sequências de tarefas matematicamente significantes. A revolução digital trouxe ferramentas poderosas. Aparecem, assim, oportunidades que exigem o assumir de novas responsabilidades. Proporcionar ambientes de aprendizagem ricos, intelectualmente livres, promotores do pensamento criativo e capazes de desenvolver eficazmente o potencial de cada aluno pressupõe mudanças na forma como se comunica e se explora o mundo. Neste contexto, a utilização de Ambientes de Geometria Dinâmica pode contribuir, por um lado, para que a Matemática seja considerada menos hostil e, por outro, para a constatação da existência de modos mais úteis de utilizar o computador na sala de aula. Estes "ambientes tecnológicos" são potenciados pela utilização de aplicações de gestão de sala de aula (CMS’s), como o iTALC. A partir da conjugação destes aspectos, desenvolveu-se um estudo que, em termos de objetivos, se propôs avaliar a influência de uma abordagem das transformações geométricas no Segundo Ciclo do Ensino Básico, com recurso àquelas ferramentas, no desenvolvimento de competências geométricas, da criatividade e de atitudes mais favoráveis em ralação à Matemática. Para isso, desenvolveu-se um estudo de caso (exploratório) envolvendo três grupos de alunos do 6.º ano de escolaridade, durante a implementação de um conjunto de tarefas de natureza essencialmente exploratória. A investigação desenvolvida sugere que: a) a criação de uma “atmosfera" de cooperação, colaboração e partilha parece suscitar incrementos nas dimensões da criatividade; b) a utilização dos Ambientes Dinâmicos de Geometria pode facilitar o aparecimento de produções mais criativas; c) o desenvolvimento de conhecimentos e capacidades geométricos parece beneficiar de uma abordagem complementar, que conjugue os ambientes digitais e os ambientes de "papel e lápis"; d) as abordagens diferentes, com carácter mais tecnológico e exploratório, parecem promover atitudes mais favoráveis em relação à Matemática, em geral, e à Geometria em particular.Creativity is recognized nowadays, as a basic skill, essential to the development of nations. In this context, society needs an Education model that is able to promote the development of creativity in their students rescuing them from inevitability to play a secondary role on the stage of global economy. However, the Education System has not been able to leverage this development, often decreasing their creative potential. On the other hand, emerges, from different reforms and curriculum programs, a growing recognition of the importance of Geometry, not only in the range of Mathematics but also in terms of the whole development of the individuals. Conceptual renewal verified in some topics, in particular, isometries, combined with the latest international guidelines for its teaching and learning demands new approaches in the classroom based in significant mathematical task sequences. The digital revolution has brought powerful tools. Therefore, opportunities appear that require the assumption of new responsibilities. Implementing rich learning environments, promoters of creative thinking and able to effectively develop the potential of each student means changes in how we communicate and explore the world. In this context, the use of Dynamic Geometry Environments can contribute, on one hand, that Mathematics is considered less hostile and, secondly, to confirm the existence of more useful ways to use computers in the classroom. These "technological environments" are enhanced by the use of Classroom Management Systems (CMS’s), such as iTALC. From the combination of these aspects, a study has been developed that, in terms of objectives, was proposed to evaluate the impact of an approach to geometric transformations in early grades, using these tools, in the development of geometrical skills, creativity, and more positive attitude towards Mathematics. For this, we developed a case study (exploratory) involving three groups of students in the 6th grade, during the implementation of a set of tasks, essentially exploratory. The research carried out suggests that: a) the creation of an "atmosphere" of cooperation, collaboration and sharing, seems to raise increments in the dimensions of creativity; b) the use of Dynamic Geometry Environments can help the emerging of more creative productions; c) the development of knowledge and geometrical skills seems to benefit from a complementary approach that combines digital environments and "Paper and Pencil" environments; d) different approaches, with a more technological and exploratory nature seem to promote more favourable attitudes towards Mathematics in general, and Geometry in particular

Characterisation of microbial attack on archaeological bone

As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved

NEOTROPICAL ALIEN MAMMALS: a data set of occurrence and abundance of alien mammals in the Neotropics

Biological invasion is one of the main threats to native biodiversity. For a species to become invasive, it must be voluntarily or involuntarily introduced by humans into a nonnative habitat. Mammals were among first taxa to be introduced worldwide for game, meat, and labor, yet the number of species introduced in the Neotropics remains unknown. In this data set, we make available occurrence and abundance data on mammal species that (1) transposed a geographical barrier and (2) were voluntarily or involuntarily introduced by humans into the Neotropics. Our data set is composed of 73,738 historical and current georeferenced records on alien mammal species of which around 96% correspond to occurrence data on 77 species belonging to eight orders and 26 families. Data cover 26 continental countries in the Neotropics, ranging from Mexico and its frontier regions (southern Florida and coastal-central Florida in the southeast United States) to Argentina, Paraguay, Chile, and Uruguay, and the 13 countries of Caribbean islands. Our data set also includes neotropical species (e.g., Callithrix sp., Myocastor coypus, Nasua nasua) considered alien in particular areas of Neotropics. The most numerous species in terms of records are from Bos sp. (n = 37,782), Sus scrofa (n = 6,730), and Canis familiaris (n = 10,084); 17 species were represented by only one record (e.g., Syncerus caffer, Cervus timorensis, Cervus unicolor, Canis latrans). Primates have the highest number of species in the data set (n = 20 species), partly because of uncertainties regarding taxonomic identification of the genera Callithrix, which includes the species Callithrix aurita, Callithrix flaviceps, Callithrix geoffroyi, Callithrix jacchus, Callithrix kuhlii, Callithrix penicillata, and their hybrids. This unique data set will be a valuable source of information on invasion risk assessments, biodiversity redistribution and conservation-related research. There are no copyright restrictions. Please cite this data paper when using the data in publications. We also request that researchers and teachers inform us on how they are using the data

Search for long-lived particles decaying to a pair of muons in proton-proton collisions at s \sqrt{s} = 13 TeV

An inclusive search for long-lived exotic particles decaying to a pair of muons is presented. The search uses data collected by the CMS experiment at the CERN LHC in proton-proton collisions at $\sqrt{s}$ = 13 TeV in 2016 and 2018 and corresponding to an integrated luminosity of 97.6 fb$^{−1}$. The experimental signature is a pair of oppositely charged muons originating from a common secondary vertex spatially separated from the pp interaction point by distances ranging from several hundred μm to several meters. The results are interpreted in the frameworks of the hidden Abelian Higgs model, in which the Higgs boson decays to a pair of long-lived dark photons Z$_{D}$, and of a simplified model, in which long-lived particles are produced in decays of an exotic heavy neutral scalar boson. For the hidden Abelian Higgs model with m(Z$_{D}$) greater than 20 GeV and less than half the mass of the Higgs boson, they provide the best limits to date on the branching fraction of the Higgs boson to dark photons for cτ(Z$_{D}$) (varying with m(Z$_{D}$)) between 0.03 and ≈0.5 mm, and above ≈0.5 m. Our results also yield the best constraints on long-lived particles with masses larger than 10 GeV produced in decays of an exotic scalar boson heavier than the Higgs boson and decaying to a pair of muons.[graphic not available: see fulltext

Search for new heavy resonances decaying to WW, WZ, ZZ, WH, or ZH boson pairs in the all-jets final state in proton-proton collisions at s\sqrt{s} = 13 TeV

International audienceA search for new heavy resonances decaying to WW, WZ, ZZ, WH, or ZH boson pairs in the all-jets final state is presented. The analysis is based on proton-proton collision data recorded by the CMS detector in 2016-2018 at a centre-of-mass energy of 13 TeV at the CERN LHC, corresponding to an integrated luminosity of 138 fb$^{-1}$. The search is sensitive to resonances with masses between 1.3 and 6 TeV, decaying to bosons that are highly Lorentz-boosted such that each of the bosons forms a single large-radius jet. Machine learning techniques are employed to identify such jets. No significant excess over the estimated standard model background is observed. A maximum local significance of 3.6 standard deviations, corresponding to a global significance of 2.3 standard deviations, is observed at masses of 2.1 and 2.9 TeV. In a heavy vector triplet model, spin-1 Z' and W' resonances with masses below 4.8 TeV are excluded at the 95% confidence level (CL). These limits are the most stringent to date. In a bulk graviton model, spin-2 gravitons and spin-0 radions with masses below 1.4 and 2.7 TeV, respectively, are excluded at 95% CL. Production of heavy resonances through vector boson fusion is constrained with upper cross section limits at 95% CL as low as 0.1 fb

Search for Higgs boson decay to a charm quark-antiquark pair in proton-proton collisions at s\sqrt{s} = 13 TeV

International audienceA search for the standard model Higgs boson decaying to a charm quark-antiquark pair, H $\to$$\mathrm{c\bar{c}}$, produced in association with a leptonically decaying V (W or Z) boson is presented. The search is performed with proton-proton collisions at $\sqrt{s}$ = 13 TeV collected by the CMS experiment, corresponding to an integrated luminosity of 138 fb$^{-1}$. Novel charm jet identification and analysis methods using machine learning techniques are employed. The analysis is validated by searching for Z $\to$$\mathrm{c\bar{c}}$ in VZ events, leading to its first observation at a hadron collider with a significance of 5.7 standard deviations. The observed (expected) upper limit on $\sigma$(VH)$\mathcal{B}$(H $\to$$\mathrm{c\bar{c}}$) is 0.94 (0.50 $^{+0.22}_{-0.15}$) pb at 95% confidence level (CL), corresponding to 14 (7.6 $^{+3.4}_{-2.3}$) times the standard model prediction. For the Higgs-charm Yukawa coupling modifier, $\kappa_\mathrm{c}$, the observed (expected) 95% CL interval is 1.1 $\lt$ $\vert\kappa_\mathrm{C}\vert$ $\lt$ 5.5 ($\vert\kappa_\mathrm{c}\vert$ $\lt$ 3.4), the most stringent constraint to date

Search for CPCP violation in ttH and tH production in multilepton channels in proton-proton collisions at s\sqrt{s} = 13 TeV

International audienceThe charge-parity (CP) structure of the Yukawa interaction between the Higgs (H) boson and the top quark is measured in a data sample enriched in the t$\overline{\textrm{t}}$H and tH associated production, using 138 fb$^{−1}$ of data collected in proton-proton collisions at $\sqrt{s}$ = 13 TeV by the CMS experiment at the CERN LHC. The study targets events where the H boson decays via H → WW or H → ττ and the top quarks decay via t → Wb: the W bosons decay either leptonically or hadronically, and final states characterized by the presence of at least two leptons are studied. Machine learning techniques are applied to these final states to enhance the separation of CP -even from CP -odd scenarios. Two-dimensional confidence regions are set on κ$_{t}$ and $\overset{\sim }{\kappa } _{t}$, which are respectively defined as the CP -even and CP -odd top-Higgs Yukawa coupling modifiers. No significant fractional CP -odd contributions, parameterized by the quantity |${f}_{CP}^{\textrm{Htt}}$| are observed; the parameter is determined to be |${f}_{CP}^{\textrm{Htt}}$| = 0.59 with an interval of (0.24, 0.81) at 68% confidence level. The results are combined with previous results covering the H → ZZ and H → γγ decay modes, yielding two- and one-dimensional confidence regions on κ$_{t}$ and $\overset{\sim }{\kappa } _{t}$, while |${f}_{CP}^{\textrm{Htt}}$| is determined to be |${f}_{CP}^{\textrm{Htt}}$| = 0.28 with an interval of |${f}_{CP}^{\textrm{Htt}}$| < 0.55 at 68% confidence level, in agreement with the standard model CP -even prediction of |${f}_{CP}^{\textrm{Htt}}$| = 0.[graphic not available: see fulltext

Observation of same-sign WW production from double parton scattering in proton-proton collisions at s\sqrt{s} = 13 TeV

International audienceThe first observation of the production of W$^\pm$W$^\pm$ bosons from double parton scattering processes using same-sign electron-muon and dimuon events in proton-proton collisions is reported. The data sample corresponds to an integrated luminosity of 138 fb$^{-1}$ recorded at a center-of-mass energy of 13 TeV using the CMS detector at the CERN LHC. Multivariate discriminants are used to distinguish the signal process from the main backgrounds. A binned maximum likelihood fit is performed to extract the signal cross section. The measured cross section for production of same-sign W bosons decaying leptonically is 80.7 $\pm$ 11.2 (stat) $^{+9.5}_{-8.6}$ (syst) $\pm$ 12.1 (model) fb, whereas the measured fiducial cross section is 6.28 $\pm$ 0.81 (stat) $\pm$ 0.69 (syst) $\pm$ 0.37 (model) fb. The observed significance of the signal is 6.2 standard deviations above the background-only hypothesis

Proton reconstruction with the CMS-TOTEM Precision Proton Spectrometer

International audienceThe Precision Proton Spectrometer (PPS) of the CMS and TOTEM experiments collected 107.7 fb$^{-1}$ in proton-proton (pp) collisions at the LHC at 13 TeV (Run 2). This paper describes the key features of the PPS alignment and optics calibrations, the proton reconstruction procedure, as well as the detector efficiency and the performance of the PPS simulation. The reconstruction and simulation are validated using a sample of (semi)exclusive dilepton events. The performance of PPS has proven the feasibility of continuously operating a near-beam proton spectrometer at a high luminosity hadron collider

Search for nonresonant Higgs boson pair production in final state with two bottom quarks and two tau leptons in proton-proton collisions at <math altimg="si1.svg"><msqrt><mrow><mi>s</mi></mrow></msqrt><mo linebreak="goodbreak" linebreakstyle="after">=</mo><mn>13</mn><mtext> TeV</mtext></math>

International audienceA search for the nonresonant production of Higgs boson pairs (HH ) via gluon-gluon and vector boson fusion processes in final states with two bottom quarks and two tau leptons is presented. The search uses data from proton-proton collisions at a center-of-mass energy of s=13TeV recorded with the CMS detector at the LHC, corresponding to an integrated luminosity of 138fb−1. Events in which at least one tau lepton decays hadronically are considered and multiple machine learning techniques are used to identify and extract the signal. The data are found to be consistent, within uncertainties, with the standard model (SM) predictions. Upper limits on the HH production cross section are set to constrain the parameter space for anomalous Higgs boson couplings. The observed (expected) upper limit at 95% confidence level corresponds to 3.3 (5.2) times the SM prediction for the inclusive HH cross section and to 124 (154) times the SM prediction for the vector boson fusion HH cross section. At 95% confidence level, the Higgs field self-coupling is constrained to be within −1.7 and 8.7 times the SM expectation, and the coupling of two Higgs bosons to two vector bosons is constrained to be within −0.4 and 2.6 times the SM expectation