Stress and anxiety negatively impact the working memory system by competing for executive resources. Broad memory deficits have been reported in individuals with chromosome 22q11.2 deletion syndrome (22q11.2DS). We investigated anxiety and physiological stress reactivity in relation to visuospatial working memory impairments in 20 children with 22q11.2DS and 32 typically developing children (M = 11.10 years, SD = 2.95). Results indicate reduced post-stress RSA recovery and overall increased levels of cortisol in children with 22q11.2DS. Additionally, anxiety mediated the relationship between 22q11.2DS and visuospatial working memory impairment. However, there was no indication that stress response physiology mediated this association. Results suggest that anxiety exacerbates impaired working memory in children with 22q11.2DS. Thus, treatment and intervention methods for children with 22q11.2DS should address anxiety related symptomology.

By means of a Monte Carlo study, this paper investigates the relative performance of Listwise Deletion, the EM-algorithm and the default algorithm in the MICE-package for R (PMM) in estimating regression coefficients under a left truncated covariate with missing values. The intention is to investigate whether the three frequently used missing data techniques are robust against left truncation when missing values are MCAR or MAR. The results suggest that no technique is superior overall in all combinations of factors studied. The EM-algorithm is unaffected by left truncation under MCAR but negatively affected by strong left truncation under MAR. Compared to the default MICE-algorithm, the performance of EM is more stable across distributions and combinations of sample size and missing rate. The default MICE-algorithm is improved by left truncation but is sensitive to missingness pattern and missing rate. Compared to Listwise Deletion, the EM-algorithm is less robust against left truncation when missing values are MAR. However, the decline in performance of the EM-algorithm is not large enough for the algorithm to be completely outperformed by Listwise Deletion, especially not when the missing rate is moderate. Listwise Deletion might be robust against left truncation but is inefficient.

No description available.

Objetivo: Investigar a presença de alterações (deleção e/ou duplicação) na região 22q11 em indivíduos até 02 anos de idade com fissura de palato, com o intuito de realizar diagnóstico precoce da síndrome da deleção 22q11 (SD22q11). Local: Laboratório de Genética e Citogenética Humana, HRAC/USP, Bauru-SP. Casuística e metodologia: Foram selecionados 55 indivíduos, de ambos os sexos, com idade até 2 anos e com fissura de palato, cadastrados e em tratamento no Hospital de Reabilitação de Anomalias Craniofaciais/USP. Todos os indivíduos foram analisados utilizando citogenética convencional por bandamento G e pela técnica de MLPA. Resultados e discussão: Foram analisados 55 indivíduos, dos quais 46 apresentaram fissura de palato isolada, 6 apresentaram fissura de palato e cardiopatia, 1 fissura de palato e atraso no desenvolvimento neuropsicomotor, 1 caso apresentou fissura de palato submucosa e 1 caso com fissura de palato submucosa e atraso no desenvolvimento neuropsicomotor. Não foram observadas anomalias cromossômicas numéricas ou estruturais por meio da análise citogenética. Embora não tenhamos encontrado nenhuma alteração, a análise citogenética inicial foi importante para detectar possíveis alterações em outras regiões cromossômicas que pudessem resultar em um fenótipo semelhante ao da SD22q11. Também não foram detectadas deleção ou duplicação na região 22q11 pela técnica de MLPA, a qual se mostrou um método rápido, sensível, eficaz e com um custo relativamente baixo em comparação a outras técnicas, para a investigação de alterações na região 22q11. Nossos resultados, associados aos da literatura, demonstram que a prevalência da deleção 22q11 nos casos de fissura de palato isolada é muito baixa. Mesmo sendo considerada como sugestiva da SD22q11, não detectamos nenhuma alteração na região 22q11 nos 6 indivíduos com cardiopatia. Somente foi possível identificar atraso no desenvolvimento em 2 indivíduos, ambos com dois anos de idade. Isso demonstra a dificuldade de realizar diagnóstico em idade precoce. Conclusão: O teste de rotina para investigação da deleção/duplicação da região 22q11 não se justifica em crianças com idade até dois anos que apresentam fissura de palato como principal achado clínico. Esses indivíduos devem ter um acompanhamento clínico criterioso, porque um comprometimento comportamental ou mental, bem como as características dismórficas da SD22q11 podem evoluir com o tempo. Devido ao tamanho relativamente pequeno desse estudo, e os dados inconsistentes da literatura atual, mais estudos são necessários para estabelecer critérios para indicação da rotina de investigação de deleção/duplicação 22q11 em indivíduos com anomalias palatinas. / Purpose: To investigate alterations (deletions/duplications) in the 22q11 region in individuals with cleft palate aged 0-2 years, in order to perform early diagnosis of 22q11 deletion syndrome (SD22q11). Local: Genetics and Human Cytogenetics Laboratory, HRAC/USP, Bauru-SP. Methods: We selected 55 individuals with cleft palate, both genders, registered and in treatment at Hospital de Reabilitação de Anomalias Craniofaciais/USP. All individuals were investigated by cytogenetics and MLPA techniques. Results and Discussion: 46 out of 55 individuals, presented isolated cleft palate, 6 cleft palate and heart malformations, 1 cleft palate and developmental delay, 1 submucous cleft, and 1 submucous cleft and developmental delay. G karyotype did not show any chromosomal abnormalities. Although we did not detect any alterations, the initial cytogenetics analysis was important to exclude alteration in other chromosomal region that could result in a similar phenotype. Deletion or duplication in 22q11 region by MLPA was not detected, which shown to be a rapid, sensitive, and low cost method in comparison with other methods to investigate 22q11 region. Results, associated with the literature, have shown that the prevalence of the 22q11 alteration is very low in cleft palate. The presence of heart malformation is suggestive of 22q11DS. Besides, there were no alterations in 22q11 region in 6 patients with cleft palate and heart malformations. We were able to identify developmental delay in only 2 individual, both aged 2 years which demonstrates the difficulty of making early diagnosis. Conclusion: There is no justification for routine screening for 22q11 region deletion/duplication in children aged 0-2 years with cleft palate as main feature. These individuals should be carefully followed because behavioral or mentalimpairments as well as dysmorphic features characteristic of 22q11DS may evolve with time.

Essa dissertação trata da pronúncia variável de /ndo/, com /d/ apagado ou pronunciado. Baseada na teoria e metodologias da Sociolinguística Variacionista (LABOV, 2006[1966], 2008[1972]), focaliza tal variável aqui referida como (NDO) na variedade paulistana do português brasileiro, através das 60 entrevistas do Projeto SP2010 (MENDES & OUSHIRO, 2012), estratificadas por Sexo/Gênero, Faixa Etária e Escolaridade. A variável (NDO) tem sido estudada desde o final dos anos 70 sob diferentes perspectivas. Alguns pesquisadores se atêm à pronúncia variável do sufixo de gerúndio (por exemplo, falano ou falando em diferentes variedades do português: Rio de Janeiro (MOLLICA, 1989), Belo Horizonte (CRISTÓFARO SILVA, 1996), João Pessoa (MARTINS, 1999, 2001), Minas Gerais (MARTINS, 2006), São José do Rio Preto (FERREIRA, 2010), Dourados e Ponta Porã MS (MARTINS e BUENO, 2011), Taboco MS (VIEIRA, 2011), Fortaleza (NASCIMENTO ET AL., 2013), Maceió (ALMEIDA e OLIVEIRA, 2017)). Leva-se em consideração o apagamento de /d/ como uma variável cujo padrão de realização pode ter especificidades na fala paulistana uma variedade que, ainda que mais detidamente estudada nos últimos anos, ainda não foi analisada no que toca a (NDO), nem no gerúndio, especificamente, nem em outros contextos morfológicos ou itens lexicais, tal como na palavra quando. O objetivo central é, então, investigar quais as variáveis linguísticas e sociais que se correlacionam à realização de (NDO). Para tanto, analisou-se qualitativa e quantitativamente a amostra, onde foram encontrados casos de apagamento de /d/ na pronúncia da Conjunção quando (93/1557) e em verbos no gerúndio (1001/4143). Segundo as análises estatísticas multivariadas, verificou-se que não há correlação significativa entre (NDO) e nenhuma das variáveis linguísticas, o apagamento ocorre com maior frequência na fala dos homens, sendo mais propício na fala daqueles com menor grau de instrução, assim como ocorre para aqueles falantes da Classe Social menos favorecida. Com relação à Faixa Etária, existe um favorecimento na fala dos mais jovens, principalmente naqueles da Faixa Etária intermediária, já para a terceira faixa existe um desfavorecimento, esses resultados levam a indícios de que o apagamento de /d/ em (NDO) seja uma variável estável na capital paulista. / This masters thesis deals with /ndo/ variable pronunciation, with /d/ deletion or pronunciation. Based on Variationist Sociolinguistics theory and methodologies (LABOV, 2006[1966], 2008[1972]), we focus on this variable here called as (NDO) on São Paulos speech of Brazilian Portuguese, through 60 interviews from SP2010 project (MENDES & OUSHIRO, 2012), stratified by Sex/Gender, Age and Level of Education. The variable (NDO) has been studied since the 1970s from different perspectives. Some researchers focused only on the pronunciation of the suffix of gerund (for example, falano or falando in different portuguese varieties as Rio de Janeiro (MOLLICA, 1989), Belo Horizonte (CRISTÓFARO SILVA, 1996), João Pessoa (MARTINS, 1999, 2001), Minas Gerais (MARTINS, 2006), São José do Rio Preto (FERREIRA, 2010), Dourados and Ponta Porã MS (MARTINS e BUENO, 2011), Taboco MS (VIEIRA, 2011), Fortaleza (NASCIMENTO ET AL., 2013), Maceió (ALMEIDA e OLIVEIRA, 2017)). Taking into account the deletion of /d/ as a variable in which the performance pattern may have specificities in Paulistano speech - a variety that, although studied in recent years, has not yet been analyzed regarding (NDO), nor in the gerund, specifically, nor in other morphological contexts or lexical items, as in the word quando. The main goal is to investigate the linguistic and social variables that are correlated to the performance of (NDO). For that, the sample was analyzed qualitatively and quantitatively, in which cases of deletion of /d/ were found in the pronunciation of the conjunction \"quando\" (93/1557) and in verbs in the gerund (1001/4143). According to the multivariate statistical analysis, it was verified that there is no significant correlation between (NDO) and the linguistic variables, deletion occurs more frequently in men\'s speech, being more propitious in the speech of those with lower Education Degree, as it occurs for those speakers of the less favored Social Class. Regarding the Age Range, there is a favoring of young people\'s speech, at all levels, the results lead to an indication that the /d/ deletion in (NDO) is a variable stability in São Paulo city.

Submitted by Jadson Francisco de Jesus SILVA (jadson@uefs.br) on 2018-02-01T23:35:20Z No. of bitstreams: 1 DISSERTA??O FINAL COM FICHA CATALOGR?FICA 18 DE ABRIL PDF (1).pdf: 2362106 bytes, checksum: 1da0ff87edbc46a6d93553a0402ab23e (MD5) / Made available in DSpace on 2018-02-01T23:35:20Z (GMT). No. of bitstreams: 1 DISSERTA??O FINAL COM FICHA CATALOGR?FICA 18 DE ABRIL PDF (1).pdf: 2362106 bytes, checksum: 1da0ff87edbc46a6d93553a0402ab23e (MD5) Previous issue date: 2017-12-19 / This research aims to investigate -r deletion in syllable coda in final position of a word in school productions, sentence dictations and letters, of students in 6th and 9th grades of Elementary School II (ES) and third year of High School (HS) of private and public schools, in the city of Feira de Santana - BA. In total, textual productions of 154 students in the two school systems were investigated. This work identifies the linguistic and social contexts that favor the deletion of the rhotic in final position of a word in each analysis, especially in the general analysis, that allows one more comprehensive and complete view of the phenomenon of the final -r deletion in writing. It is also shown the role of the school in the expansion or not of the linguistic competence in the written task as the student advances to the final grades of ES II and HS. For the development of this sociolinguistic research, the quantitative method was used with the support of the Goldvarb X program and the analyses were made in light of the Labovian linguistic variation theory, theoretical current that considers the heterogeneity is systematic and inherent in the language and variation can lead to a process of language change. The erasing of the -r in final position of a word was a variable rule, being suppressed, mainly, in some linguistic contexts. Regarding the linguistic factors, the most relevant were the grammatical class, the number of syllables, the preceding vowel of the word. Regarding the external variable, the textual genre was selected. Regarding the social factors, the most favorable factors were the grade/school year, especially the younger groups, the school system, stressing the public one, and parents and children?s origin. This research provides a better understanding of the linguistic heterogeneity of the phenomenon in question, not only in terms of spoken language but also of writing in the community of Feira de Santana, which calls for more investigations. / Este trabalho tem como objetivo investigar o apagamento do -r em final de palavras em produ??es escolares, ditados de frases e cartas, dos alunos do 6? e do 9? anos do Ensino Fundamental II (EF) e do 3? ano do Ensino M?dio (EM), das redes particular e p?blica da cidade de Feira de Santana ? BA. No total foram investigadas produ??es textuais de 154 alunos pertencentes ?s duas redes de ensino. Neste trabalho, identificam-se os contextos lingu?sticos e extralingu?sticos que favorecem o apagamento do r?tico em final de palavras em cada uma das an?lises, em especial na an?lise geral, que possibilita uma vis?o mais ampla e completa do fen?meno do apagamento do -r final na escrita. Busca-se tamb?m verificar o papel da escola na amplia??o ou n?o da compet?ncia lingu?stica na modalidade escrita ? medida que o aluno avan?a para as s?ries finais do EF II e do EM. Para o desenvolvimento desta pesquisa, de cunho sociolingu?stico, utilizou-se o m?todo quantitativo com o suporte do programa Goldvarb X e as an?lises foram feitas ? luz da teoria da varia??o lingu?stica laboviana, corrente te?rica que considera que a heterogeneidade ? sistem?tica e inerente ? l?ngua e que a varia??o pode levar a um processo de mudan?a na l?ngua. Em final de voc?bulo, o apagamento do -r final apresentou-se como uma regra vari?vel, sendo suprimido, sobretudo, em alguns contextos lingu?sticos. Sobre os grupos de fatores lingu?sticos, os mais relevantes foram a classe gramatical, o n?mero de s?labas e a vogal precedente do voc?bulo. Tamb?m se mostrou importante a vari?vel externa g?nero textual. Sobre os fatores extralingu?sticos, os maiores favorecedores foram a s?rie/ano escolar, em especial as dos mais jovens, o grupo da rede de ensino, com destaque para a rede p?blica, e a origem de pais e filhos. Este trabalho possibilita uma melhor compreens?o da heterogeneidade lingu?stica sofre o fen?meno em quest?o, n?o s? em termos de l?ngua falada mas tamb?m da escrita na comunidade feirense, que ainda carece de investiga??es mais profundas.

A síndrome de Sotos (MIM 117550) é caracterizada pelo crescimento pré e pós-natal acelerado, fácies típica com testa proeminente, hipertelorismo, estrabismo, fissura palpebral antimongolóide, as orelhas grandes, o palato alto e estreito, mãos e pés grandes e possibilidade de erupção prematura dos dentes. É também freqüentemente associada com anomalias cerebrais, cardiovasculares e urinárias, e, ocasionalmente, é acompanhado por lesões malignas, como tumor de Wilms e hepatocarcinoma. Com o avanço da idade, a face gradualmente se alonga, o queixo fica mais proeminente, a altura chega próxima ao normal e a macrocefalia não é mais pronunciada. A casuística total foi de 65 pacientes com suspeita de diagnóstico clínico da síndrome de Sotos. Esses 65 pacientes foram testados por MLPA com o Kit Salsa P026B e três deleções foram encontradas: deleção total do gene FGFR4 e regiões flanqueadas, incluindo o gene FGFR4 e dois casos de deleções parciais do gene, uma com os exons 13 e 14 deletados, e outra com deleção desde o gene FGFR4 até o exon 17 do gene FGFR4, todas \"de novo\". Na nossa amostra a freqüência de deleções foi de cerca de 5%, semelhante à observada nas populações nãojaponesas. Os pacientes com as deleções apresentam a \"fácies típica\" com abaulamento frontal, o queixo proeminente, a implantação frontal do cabelo alta; a macrocefalia, a dolicocefalia, as mãos grandes; a hipotonia neonatal e a icterícia neonatal também estão presentes nos três pacientes. Entretanto, os três pacientes nasceram com o comprimento e o peso dentro dos padrões de normalidade e não acima do percentil 97 como descrito para a Sos. Para a pesquisa de mutações no gene FGFR4, foram selecionados trinta pacientes com \"fácies típica\" da síndrome de Sotos e macrocefalia. O seqüenciamento até o momento foi realizado em quatro pares de \"primers\" referentes ao exon 5 do gene FGFR4. Dois SNPs foram encontrados, um no fragmento 5B e um no fragmento 5D. Os dois SNPs ocorreram por uma substituição da base nitrogenada C-> T e são substituições sinônimas. A comparação do estudo de Tatton-Brown, et al, (2005b) que analisou as características clínicas e comportamentais de 266 pacientes com síndrome de Sotos, cujo mecanismo genético foi desvendado, com a nossa amostra de 30 pacientes nos permitiu sugerir como critérios mínimos para o diagnóstico clínico da síndrome de Sotos a \"fácies típica\" (abaulamento frontal, testa proeminente, hipertelorismo, estrabismo, fissura palpebral antimongolóide) e a macrocefalia. As alterações no gene FGFR4 (microdeleções e mutações) são essencialmente específicas para a síndrome de Sotos e, por isso, o diagnóstico genético para qualquer caso em que haja alteração do gene FGFR4, é o de síndrome de Sotos. / Sotos syndrome (MIM 117550) is autosomal dominant condition characterized by prenatal and postnatal overgrowth, macrocephaly and a typical facial gestalt with frontal bossing, hypertelorism, antimongoloid slant of the palpebral fissures, prominent jaw, large ears, high and narrow palate and large hands and feet. The syndrome is also frequently associated with brain, cardiovascular, and urinary anomalies and is occasionally accompanied by malignant lesions such Wilms tumour and hepatocarcinoma. FGFR4 microdeletions were investigated in sixty five patients with clinical diagnosis of Sotos syndrome by multiplex ligation dependent probe amplification ( MLPA, Kit Salsa P026B). We identified one patient with a total deletion of FGFR4 and FGFR4, one with FGFR4 exon13-14 deletion and another with a deletion that included FGFR4 and FGFR4 exon1-17. All deletions were \"de novo\". In our sample, the frequency of deletions was ~5%, similar to that found in non-Japanese populations. The clinical features of the three patients with microdeletions are: the typical facial gestalt with frontal bossing, prominent jaw and high anterior hairline; macrocephaly, dolichocephaly, large hands; neonatal hypotonia and jaundice. However, those three patients presented normal length and weight at birth. Clinical and behavioral features of 30 patients presenting a typical facial gestalt and macrocephaly, cardinal characteristics of Sotos syndrome were described. The comparison of the clinical and behavioral features to those described for 266 patients with a genetic diagnosis of Sotos syndrome indicates that a high clinical suspition of Sotos syndrome includes the typical facial gestalt (frontal bossing, hipertelorism, strabismus, prominent jaw, antimongoloid slant of the palpebral fissures) and macrocephaly. Other features associated with Sotos syndrome, such as overgrowth, learning disability, behavioral problems confirms the clinical diagnosis. FGFR4 microdeletion investigations detects only 5% of the Brazilian patients with Sotos syndrome. Screening for intragenic FGFR4 mutations may not be necessary in classic Sotos syndrome cases. However, identification of an FGFR4 abnormality is diagnostic of Sotos syndrome.

Essa dissertação trata da pronúncia variável de /ndo/, com /d/ apagado ou pronunciado. Baseada na teoria e metodologias da Sociolinguística Variacionista (LABOV, 2006[1966], 2008[1972]), focaliza tal variável aqui referida como (NDO) na variedade paulistana do português brasileiro, através das 60 entrevistas do Projeto SP2010 (MENDES & OUSHIRO, 2012), estratificadas por Sexo/Gênero, Faixa Etária e Escolaridade. A variável (NDO) tem sido estudada desde o final dos anos 70 sob diferentes perspectivas. Alguns pesquisadores se atêm à pronúncia variável do sufixo de gerúndio (por exemplo, falano ou falando em diferentes variedades do português: Rio de Janeiro (MOLLICA, 1989), Belo Horizonte (CRISTÓFARO SILVA, 1996), João Pessoa (MARTINS, 1999, 2001), Minas Gerais (MARTINS, 2006), São José do Rio Preto (FERREIRA, 2010), Dourados e Ponta Porã MS (MARTINS e BUENO, 2011), Taboco MS (VIEIRA, 2011), Fortaleza (NASCIMENTO ET AL., 2013), Maceió (ALMEIDA e OLIVEIRA, 2017)). Leva-se em consideração o apagamento de /d/ como uma variável cujo padrão de realização pode ter especificidades na fala paulistana uma variedade que, ainda que mais detidamente estudada nos últimos anos, ainda não foi analisada no que toca a (NDO), nem no gerúndio, especificamente, nem em outros contextos morfológicos ou itens lexicais, tal como na palavra quando. O objetivo central é, então, investigar quais as variáveis linguísticas e sociais que se correlacionam à realização de (NDO). Para tanto, analisou-se qualitativa e quantitativamente a amostra, onde foram encontrados casos de apagamento de /d/ na pronúncia da Conjunção quando (93/1557) e em verbos no gerúndio (1001/4143). Segundo as análises estatísticas multivariadas, verificou-se que não há correlação significativa entre (NDO) e nenhuma das variáveis linguísticas, o apagamento ocorre com maior frequência na fala dos homens, sendo mais propício na fala daqueles com menor grau de instrução, assim como ocorre para aqueles falantes da Classe Social menos favorecida. Com relação à Faixa Etária, existe um favorecimento na fala dos mais jovens, principalmente naqueles da Faixa Etária intermediária, já para a terceira faixa existe um desfavorecimento, esses resultados levam a indícios de que o apagamento de /d/ em (NDO) seja uma variável estável na capital paulista. / This masters thesis deals with /ndo/ variable pronunciation, with /d/ deletion or pronunciation. Based on Variationist Sociolinguistics theory and methodologies (LABOV, 2006[1966], 2008[1972]), we focus on this variable here called as (NDO) on São Paulos speech of Brazilian Portuguese, through 60 interviews from SP2010 project (MENDES & OUSHIRO, 2012), stratified by Sex/Gender, Age and Level of Education. The variable (NDO) has been studied since the 1970s from different perspectives. Some researchers focused only on the pronunciation of the suffix of gerund (for example, falano or falando in different portuguese varieties as Rio de Janeiro (MOLLICA, 1989), Belo Horizonte (CRISTÓFARO SILVA, 1996), João Pessoa (MARTINS, 1999, 2001), Minas Gerais (MARTINS, 2006), São José do Rio Preto (FERREIRA, 2010), Dourados and Ponta Porã MS (MARTINS e BUENO, 2011), Taboco MS (VIEIRA, 2011), Fortaleza (NASCIMENTO ET AL., 2013), Maceió (ALMEIDA e OLIVEIRA, 2017)). Taking into account the deletion of /d/ as a variable in which the performance pattern may have specificities in Paulistano speech - a variety that, although studied in recent years, has not yet been analyzed regarding (NDO), nor in the gerund, specifically, nor in other morphological contexts or lexical items, as in the word quando. The main goal is to investigate the linguistic and social variables that are correlated to the performance of (NDO). For that, the sample was analyzed qualitatively and quantitatively, in which cases of deletion of /d/ were found in the pronunciation of the conjunction \"quando\" (93/1557) and in verbs in the gerund (1001/4143). According to the multivariate statistical analysis, it was verified that there is no significant correlation between (NDO) and the linguistic variables, deletion occurs more frequently in men\'s speech, being more propitious in the speech of those with lower Education Degree, as it occurs for those speakers of the less favored Social Class. Regarding the Age Range, there is a favoring of young people\'s speech, at all levels, the results lead to an indication that the /d/ deletion in (NDO) is a variable stability in São Paulo city.

Recently, there has been a renewed interest in code based cryptosystems. Amongst the reasons for this interest is that they have shown to be resistant to quantum at- tacks, making them candidates for post-quantum cryptosystems. In fact, the National Institute of Standards and Technology is currently considering candidates for secure communication in the post-quantum era. Three of the proposals are code based cryp- tosystems. Other reasons for this renewed interest include e cient encryption and decryption. In this dissertation, new code based cryptosystems (symmetric key and public key) are presented that use high rate codes and have small key sizes. Hence they overcome the drawbacks of code based cryptosystems (low information rate and very large key size). The techniques used in designing these cryptosystems include random bit/block deletions, random bit insertions, random interleaving, and random bit ipping. An advantage of the proposed cryptosystems over other code based cryp- tosystems is that the code can be/is not secret. These cryptosystems are among the rst with this advantage. Having a public code eliminates the need for permutation and scrambling matrices. The absence of permutation and scrambling matrices results in a signi cant reduction in the key size. In fact, it is shown that with simple random bit ipping and interleaving the key size is comparable to well known symmetric key cryptosystems in use today such as Advanced Encryption Standard (AES). The security of the new cryptosystems are analysed. It is shown that they are immune against previously proposed attacks for code based cryptosystems. This is because scrambling or permutation matrices are not used and the random bit ipping is beyond the error correcting capability of the code. It is also shown that having a public code still provides a good level of security. This is proved in two ways, by nding the probability of an adversary being able to break the cryptosystem and showing that this probability is extremely small, and showing that the cryptosystem has indistinguishability against a chosen plaintext attack (i.e. is IND-CPA secure). IND-CPA security is among the primary necessities for a cryptosystem to be practical. This means that a ciphertext reveals no information about the corresponding plaintext other than its length. It is also shown that having a public code results in smaller key sizes. / Graduate

Ces travaux s'inscrivent dans le cadre des recherches menées dans le cadre d'une collaboration entre le laboratoire Roberval de l'Université de Technologie de Compiègne et l'équipe dans le cadre du projet ANR-14-CE07-0035 LASMIS de l'Institut Charles Delaunay de l'Université de Technologie de Troyes. Nous présentons dans ces travaux une h-méthodologie adaptative tridimensionnelle des éléments finis afin de représenter l'initiation et la propagation des fissures dans des matériaux ductiles. Un modèle élasto-plastique couplé à l'endommagement isotrope proposé par l'équipe du LASMIS/UTT est utilisé. Les applications visées à terme concernent principalement la mise en forme des métaux. Dans ce contexte, une formulation Lagrangienne actualisée est employée et des remaillages fréquents s'avèrent essentiels afin d'une part d'éviter les fortes distorsions d'éléments dues aux grandes déformations plastiques et d'autre part de suivre les modifications de la topologie résultant de la création de fissures. La taille du nouveau maillage doit permettre à moindre coût représenter avec précision l'évolution des gradients des quantités physiques représentatives des phénomènes étudiées (plasticité, endommagement...). Nous proposons des indicateurs empiriques de taille d'éléments basés sur la déformation plastique ainsi que sur l'endommagement. Une courbe définie par morceau représente l'évolution de la taille d'élément suivant la sévérité de la plasticité et le cas échéant de l'endommagement. Les fissures sont représentées par une méthode de destruction d'éléments qui permet une description aisée de la géométrie de ces dernières et une gestion simplifiée de la fissuration sans nul besoin de critères additionnels. En revanche, pour permettre une description réaliste des fissures, ces dernières doivent être représentées par l'érosion des éléments de plus petite taille. Un solveur ABAQUS/Explicit® est utilisé avec des éléments tétraédriques quadratiques (C3D10M) évitant notamment les problèmes de verrouillage numérique survenant lors de l'analyse de structures en matériau compressible ou quasi-incompressible. Le contrôle de la plus petite taille du maillage est important dans un contexte explicite. De surcroît, pour les phénomènes adoucissant, la solution dépend de la taille de maille considérée alors comme un paramètre intrinsèque. Une étude nous a permis de constater que lorsque le maillage est suffisamment raffiné, les effets de la dépendance au maillage se réduisaient. Dans la littérature, les coûts de maillage ou de remaillage fréquents sont souvent considérés comme prohibitifs et de nombreux auteurs s'appuient sur cet argument pour introduire, avec succès certes, des méthodes alternatives qui limitent le coût des opérations de remaillage sans toutefois les éliminer (XFEM par exemple). Nos travaux montrent que le coût d'un remaillage local est négligeable par rapport au calcul. Compte tenu de la complexité de la géométrie et de la nécessité de raffiner le maillage, la seule alternative à ce jour est d'utiliser un mailleur en tétraèdres. La stratégie de remaillage local en tétraèdre s'appuie sur une méthode de bisection suivie si nécessaire d'une optimisation locale du maillage proposé par A. Rassineux en 2003. Le remaillage, même local, doit s'accompagner de procédures de transfert de champ des variables nodales et aux points d'intégration. Les variables nodales sont, comme le fait la plupart des auteurs, transférées en utilisant les fonctions de forme éléments finis. Le transfert de champ en 3D aux points de Gauss et les nombreux problèmes sous-jacents ont été relativement peu abordés dans la littérature. / This work is part of the research carried out in the framework of a collaboration between the Roberval laboratory of the Compiègne University of Technology and the team within the framework of the project ANR-14-CE07-0035 LASMIS of the Charles Delaunay Institute of Technology University of Troyes. In this work, we present a three-dimensional adaptive Pi-methodology of finite elements to represent the initiation and propagation of cracks in ductile materials. An elastoplastic model coupled with the isotropic damage proposed by the LASMIS / UTT team is used. The targeted applications will mainly concern the metal forming. In this context, an updated Lagrangian formulation is used and frequent remeshing is essential in order to avoid the strong distortion of elements due to large plastic deformations and to follow the modifications of the topology resulting in the creation of cracks. The size of the new mesh must allow at a lower cost to accurately represent the evolution of the gradients of the physical quantities representative of the studied phenomena (plasticity, damage ...). We propose empirical indicators of size of elements based on the plastic deformation as well as on the damage. A piecewise defined curve represents the evolution of the element size according to the severity of the plasticity and, if appropriate, the damage. The cracks are represented by a method of destruction of elements which allows an easy description of the geometry and a simplified treatment of the cracking without any need for additional criteria. On the other hand, to allow a realistic description of the cracks, the latter must be represented by erosion smaller elements. An ABAQUS / Explicit@ solver is used with quadratic tetrahedral elements (C3DIOM), avoiding in particular the problems of numerical locking occurring during the analysis of structures in compressible or quasi-incompressible material. The control of the smaller mesh size is important in an explicit context. In addition, for softening phenomena, the solution depends on the mesh size considered as an intrinsic parameter. A study has shown that when the mesh is sufficiently refined, the effects of mesh dependence are reduced. In the literature, the costs of frequent meshing or remeshing are often considered prohibitive and many authors rely on this argument to introduce, with success, alternative methods that limit the cost of remeshing operations without eliminating them ( XFEM for example). Our work shows that the cost of local remeshing is negligible compared to the calculation. Given the complexity of the geometry and the need to refine the mesh, the only alternative to date is to use a mesh in tetrahedra. The strategy of local remeshing tetrahedron is based on a bisection method followed if necessary by a local optimization of the grid proposed by A. Rassineux in 2003. The remeshing, even local, must be accompanied by field transfer procedures on both nodal variables and integration points. Node variables are, as most authors do, transferred using finite element shape functions. The 3D field transfer at Gauss points and the many underlying problems have been relatively untouched in the literature. The main difficulties to be solved in order to ensure the "quality" of the transfer concern the limitation of numerical diffusion, the lack of information near borders, the respect of boundary conditions, the equilibrium, the calculation costs, the filtering of the information points, crucial problems in 3D where the number of Gauss points used is several hundred. We propose a so-called "hybrid" method which consists, initially, in extrapolating the data at the Gauss points, in the nodes by diffuse interpolation and then in using the finite element form functions to obtain the value at the point considered.