A4A_4 symmetry at colliders and in the universe

Two puzzling facts of our time are the observed patterns in the fermion masses and mixings and the existence of non-baryonic dark matter, which are both often associated with extensions of the Standard Model at higher energy scales. In this paper, we consider a solution to these two problems with the flavour symmetry ${\mathbb A}_4\times {\mathbb Z}_2\times {\mathbb Z}_2^\prime$, in a model which has been shown before to explain large leptonic mixings with a specific texture. The model contains 3 generations of $SU(2)_L$-doublet scalar fields, arranged as an ${\mathbb A}_4$-triplet, that spontaneously break the electroweak symmetry, and a "dark sector" of ${\mathbb Z}_2$-odd fields, containing one Majorana neutrino and an ${\mathbb A}_4$-triplet $SU(2)_L$-doublet scalar field, the lightest of which provides a candidate for dark matter. Concerning the ${\mathbb Z}_2$-even scalar fields, compared to the Standard Model, we predict additional fields with masses at the electroweak scale. We therefore investigate present phenomenological constraints from lepton flavour violation experiments, obtaining a lower bound on the extra scalar masses of 140 GeV. Furthermore we consider the oblique parameters, Higgs boson decay properties and possible flavour violating signals at the LHC. Concerning the "dark sector", we study bounds from dark matter search experiments and identify the parameter space of the dark matter candidate that is compatible with the observed relic density. We find two allowed mass ranges for the dark matter within which the experimental constraints can be accommodated: the low-mass range is from 47 GeV to 74 GeV and the high-mass range is from 600 GeV and 3.6 TeV.Comment: v2, to be published in JHE

Towards predictive flavour models in SUSY SU(5) GUTs with doublet-triplet splitting

We discuss how the double missing partner mechanism solution to the doublet-triplet splitting problem in four-dimensional supersymmetric SU(5) Grand Unified Theories (GUTs) can be combined with predictive models for the quark-lepton Yukawa coupling ratios at the GUT scale. It is argued that towards this goal a second SU(5) breaking Higgs field in the adjoint representation is very useful and we discuss all possible renormalizable superpotentials with two adjoint Higgs fields and calculate the constraints on the GUT scale and effective triplet mass from a two-loop gauge coupling unification analysis. Two explicit flavour models with different predictions for the GUT scale Yukawa sector are presented, including shaping symmetries and a renormalizable messenger sector. Towards calculating the rates for proton decay induced by the exchange of colour triplets, the required Clebsch-Gordan coefficients for their couplings are calculated for the possible dimension five and six operators. They are provided in detailed tables in the appendix, together with additional helpful material for GUT flavour model building.Comment: 47 pages, 9 figures; version published in JHE

Distribution of particles which produces a "smart" material

If $A_q(\beta, \alpha, k)$ is the scattering amplitude, corresponding to a potential $q\in L^2(D)$, where $D\subset\R^3$ is a bounded domain, and $e^{ik\alpha \cdot x}$ is the incident plane wave, then we call the radiation pattern the function $A(\beta):=A_q(\beta, \alpha, k)$, where the unit vector $\alpha$, the incident direction, is fixed, and $k>0$, the wavenumber, is fixed. It is shown that any function $f(\beta)\in L^2(S^2)$, where $S^2$ is the unit sphere in $\R^3$, can be approximated with any desired accuracy by a radiation pattern: $||f(\beta)-A(\beta)||_{L^2(S^2)}<\epsilon$, where $\epsilon>0$ is an arbitrary small fixed number. The potential $q$, corresponding to $A(\beta)$, depends on $f$ and $\epsilon$, and can be calculated analytically. There is a one-to-one correspondence between the above potential and the density of the number of small acoustically soft particles $D_m\subset D$, $1\leq m\leq M$, distributed in an a priori given bounded domain $D\subset\R^3$. The geometrical shape of a small particle $D_m$ is arbitrary, the boundary $S_m$ of $D_m$ is Lipschitz uniformly with respect to $m$. The wave number $k$ and the direction $\alpha$ of the incident upon $D$ plane wave are fixed.It is shown that a suitable distribution of the above particles in $D$ can produce the scattering amplitude $A(\alpha',\alpha)$, $\alpha',\alpha\in S^2$, at a fixed $k>0$, arbitrarily close in the norm of $L^2(S^2\times S^2)$ to an arbitrary given scattering amplitude $f(\alpha',\alpha)$, corresponding to a real-valued potential $q\in L^2(D)$.Comment: corrected typo

Close to Uniform Prime Number Generation With Fewer Random Bits

In this paper, we analyze several variants of a simple method for generating prime numbers with fewer random bits. To generate a prime $p$ less than $x$, the basic idea is to fix a constant $q\propto x^{1-\varepsilon}$, pick a uniformly random $a<q$ coprime to $q$, and choose $p$ of the form $a+t\cdot q$, where only $t$ is updated if the primality test fails. We prove that variants of this approach provide prime generation algorithms requiring few random bits and whose output distribution is close to uniform, under less and less expensive assumptions: first a relatively strong conjecture by H.L. Montgomery, made precise by Friedlander and Granville; then the Extended Riemann Hypothesis; and finally fully unconditionally using the Barban-Davenport-Halberstam theorem. We argue that this approach has a number of desirable properties compared to previous algorithms.Comment: Full version of ICALP 2014 paper. Alternate version of IACR ePrint Report 2011/48

A Quantum-Proof Non-Malleable Extractor, With Application to Privacy Amplification against Active Quantum Adversaries

In privacy amplification, two mutually trusted parties aim to amplify the secrecy of an initial shared secret $X$ in order to establish a shared private key $K$ by exchanging messages over an insecure communication channel. If the channel is authenticated the task can be solved in a single round of communication using a strong randomness extractor; choosing a quantum-proof extractor allows one to establish security against quantum adversaries. In the case that the channel is not authenticated, Dodis and Wichs (STOC'09) showed that the problem can be solved in two rounds of communication using a non-malleable extractor, a stronger pseudo-random construction than a strong extractor. We give the first construction of a non-malleable extractor that is secure against quantum adversaries. The extractor is based on a construction by Li (FOCS'12), and is able to extract from source of min-entropy rates larger than $1/2$. Combining this construction with a quantum-proof variant of the reduction of Dodis and Wichs, shown by Cohen and Vidick (unpublished), we obtain the first privacy amplification protocol secure against active quantum adversaries

Lateralized neural responses to letters and digits in first graders.

The emergence of visual cortex specialization for culturally acquired characters like letters and digits, both arbitrary shapes related to specific cognitive domains, is yet unclear. Here, 20 young children (6.12 years old) were tested with a frequency-tagging paradigm coupled with electroencephalogram recordings to assess discrimination responses of letters from digits and vice-versa. One category of stimuli (e.g., letters) was periodically inserted (1/5) in streams of the other category (e.g., digits) presented at a fast rate (6 Hz). Results show clear right-lateralized discrimination responses at 6 Hz/5 for digits within letters, and a trend for left-lateralization for letters. These results support an early developmental emergence of ventral occipito-temporal cortex specialization for visual recognition of digits and letters, potentially in relation with relevant coactivated brain networks

Sobrevida de felinos após uso de retalho cutâneo na reconstrução facial por acometimento neoplásico

Na oncologia, a técnica cirúrgica reconstrutiva é muito utilizada para correção dos defeitos de pele e estruturas resultantes da exérese tumoral. Os retalhos dérmicos locais são o principal artifício da cirurgia reconstrutiva, sendo mais frequentemente utilizados para o fechamento de extensas lesões, proporcionando um bom efeito estético. O objetivo deste estudo é contabilizar a sobrevida que obtiveram os felinos acometidos por tumores após o método de reconstrução facial. Para tal, foram coletados dados de cinco pacientes da espécie felina atendidos no Hospital de Clínicas Veterinárias da Universidade Federal do Rio Grande do Sul (HCV/UFRGS) no período de janeiro de 2017 a junho de 2018. Analisaram-se informações referente aos pacientes como: raça, todos sem raça definida; idade, predomínio de animais adultos a idosos; sexo, 3 machos e 2 fêmeas; pelagem, 80% dos animais com pelagem clara; localização, face; tamanho tumoral, amplas lesões sem simetria definida. Realizou-se o diagnóstico tumoral dos pacientes, sendo: 3 por carcinoma de células escamosas, 1 por fibrossarcoma e 1 por sarcóide. Também foi avaliado dados relacionados à técnica cirúrgica como: tipo de retalho utilizado, predominância por retalhos de avanço, rotação e transposição; complicações referentes à cirurgia, retardo cicatricial, necrose e recidiva e a sobrevida dos animais.In oncology, the reconstructive surgical technique is widely used for correction of skin defects and structures resulting from tumor excision. Local dermal flaps are the main artifice of reconstructive surgery, being most often used to close extensive lesions, providing a good aesthetic effect. The objective of this study is to account for the survival of felines affected by tumors after the facial reconstruction method. For this purpose, data were collected from five patients of the feline species treated at the Hospital of Veterinary Clinics of the Federal University of Rio Grande do Sul (HCV / UFRGS) from January 2017 to October 2018. Breed; all without defined race, age; prevalence of adult animals to the elderly, sex; 3 males and 2 females, fur; 80% of animals with light coat, location; face, tumor size; large lesions without defined symmetry. The patients were diagnosed tumor, being: 3 by squamous cell carcinoma, 1 by fibrosarcoma and 1 by sarcoid. We also evaluated data related to the surgical technique such as: type of flap used; predominance of advancement flaps, rotation and transposition; complications related to surgery; cicatricial delay, necrosis and relapse and survival of the animals

Pensamento computacional e compreensão leitora : como estes conceitos se relacionam e como associá-los a obras de literatura infantil que abordam a matemática nos anos iniciais?

O presente trabalho tem por finalidade analisar obras de literatura infantil que abordam a Matemática nos Anos Iniciais do ensino fundamental sobre o prisma do Pensamento Computacional e da compreensão leitora demonstrando como estas habilidades metacognitivas podem estar aliadas com a finalidade de contribuir no entendimento de textos. Os objetivos que balizaram a investigação foram o de pesquisar e descrever o Pensamento Computacional e a compreensão leitora, bem como estabelecer possíveis relações entre eles. Por fim, analisar obras de literatura por meio deste construto teórico, de modo que se possa utilizar estratégias didáticas no intuito de subsidiar práticas pedagógicas em que os referidos conceitos estejam presentes, foi também pretensão desta escrita. A discussão deste estudo foi baseada em autores que versam sobre o Pensamento Computacional e a compreensão leitora, tais como Bagno (2012), Marcuschi (2020), Solé (2014), Goodman (1987), Papert (1980; 1994), Resnick (2020), Wing (2016), Brackmann (2017), Liukas (2019), entre outros. A pesquisa qualitativa, de cunho documental, através do referencial teórico selecionado, teve o material empírico analisado a partir de cinco categorias, a saber: abstração/seleção, decomposição/predição, reconhecimento de padrões/inferência, algoritmo/confirmação, depuração/autocorreção. Para referir brevemente do que tratam estes conceitos, pontua-se que a abstração/seleção acontece quando o leitor retém em sua memória somente as informações lidas que são mais importantes para o entendimento. Decomposição/predição são pequenas pausas feitas na leitura para prever o assunto que virá na sequência durante o ato de ler. Já o reconhecimento de padrões/inferência ocorre no momento em que se lê aquilo que está subentendido, ou seja, as relações possíveis do conteúdo textual com os conhecimentos prévios do leitor. Algoritmo/confirmação dá-se quando se realiza síntese do que foi lido. Por último, a estratégia de depuração/autocorreção é acionada na ocasião em que o leitor precisa avaliar e retificar um possível equívoco cometido durante a leitura. As considerações finais apontam que, embora a compreensão leitora e as habilidades do Pensamento Computacional não se circunscrevem às que foram descritas neste trabalho, estas avaliadas na discussão teórica se mostram ser um meio didático para promover a proficiência em leitura

O “NOVO” DIREITO INTERNACIONAL DO DESENVOLVIMENTO' CONCEITOS E FUNDAMENTOS CONTEMPORÂNEOS

A partir da década de 1990, o direito internacional do desenvolvimento passou aassociar-se a novos vetores da governança global: a sua inter-relação com os direitos humanos,a sua associação com a preservação ambiental, bem como a institucionalização dos Objetivos doDesenvolvimento do Milênio. Em razão disso, o presente artigo sustenta que o direito internacional do desenvolvimento vem passando por um processo de transformação dos seus valores,tornou-se menos ideologizado, menos adstrito ao antagonismo Norte e Sul, e mais condizentecom a noção de interdependência global, que orienta a solução dos desafios das relações internacionais contemporâneas