Complex Algebras of Arithmetic

An 'arithmetic circuit' is a labeled, acyclic directed graph specifying a sequence of arithmetic and logical operations to be performed on sets of natural numbers. Arithmetic circuits can also be viewed as the elements of the smallest subalgebra of the complex algebra of the semiring of natural numbers. In the present paper, we investigate the algebraic structure of complex algebras of natural numbers, and make some observations regarding the complexity of various theories of such algebras

Alterações patológicas da cavidade oral relacionadas ao estresse e a ansiedade

Distúrbios psicológicos, como o estresse e a ansiedade, podem causar alterações fisiológicas com a capacidade de influenciar no surgimento e agravamento de diferentes patologias com manifestação oral. Entre elas está a disfunção temporomandibular, doença periodontal, herpes simples, líquen plano, ulceração aftosa e mucosa mordiscada. A presente revisão de literatura tem como objetivo discorrer sobre o impacto do estresse a da ansiedade na cavidade bucal e as possíveis patologias associadas, para por fim ressaltar a importância de o cirurgião dentista abranger, além do exame físico, uma criteriosa anamnese, analisando também o contexto psicossocial do paciente. Para isto, foi feito um levantamento nas bases de dados PubMed, Google Acadêmico e Scielo, utilizando os termos de pesquisa (em português e inglês): estresse e ansiedade,  patologias bucais causadas pelo estresse, estresse e saúde bucal, problemas de saúde bucal relacionados a ansiedade e estresse, consequências do estresse na saúde bucal, disfunção temporomandibular, líquen  plano, doenças periodontais, herpes simples, ulceração aftosa e mucosa mordiscada. Conclui-se que ainda são necessários mais estudos e pesquisas a respeito do tema, devido a etiologia multifatorial ou não muito bem elucidada das patologias mencionadas. entretanto, fica clara a relação do estresse e da ansiedade com o surgimento e agravamento de diferentes patologias orais, reforçando a importância de uma anamnese criteriosa e tratamento multidisciplinar

Atlas histológico virtual e interativo para as escolas do PROUCA

Anais do II Seminário Seminário Estadual PIBID do Paraná: tecendo saberes / organizado por Dulcyene Maria Ribeiro e Catarina Costa Fernandes — Foz do Iguaçu: Unioeste; Unila, 2014No Programa Um Computador por Aluno-PROUCA, a disponibilidade de materiais didáticos é limitada. Para diminuir este déficit foi elaborado um atlas virtual histológico, baseado no acervo do Departamento de Biologia Celular da UFPR. Optou-se pela linguagem HTML5 como padrão de desenvolvimento por esta ser universalmente aceita em qualquer dispositivo que possua um navegador para web. O aplicativo apresenta de forma interativa as lâminas onde estão presentes os tecidos histológicos. O aluno posiciona o ponteiro do mouse sobre um menu e as estruturas teciduais correspondentes ficam evidenciadas em tons de cores. Textos didáticos e links para vídeos na internet são disponibilizados. Avalia-se que este Atlas virtual seja um diferencial no aprendizado dos alunos que utilizem esse sistem

Hypersexual behavior in a large online sample: Individual characteristics and signs of coercive sexual behavior

Background and aims Despite the high prevalence of perceived problems relating to symptoms of hypersexual disorder (HD), important aspects remain underinvestigated. This study examines symptoms of depression, symptoms of problematic cybersex, and coercive sexual behavior in a large online sample from a German-speaking population. Methods In an online survey, N = 1,194 (n = 564 women) participated in this study and completed measures including self-report questionnaires to assess depressive symptoms (PHQ-9), HD (HBI-19), symptoms of problematic cybersex (s-IATsex), as well as questions characterizing participants sexually, including fantasies and actual sexual coercive behaviors. Results Men reported increased levels of HD symptom severity, pornography consumption, masturbation, and partnered sexual activity. Moreover, 59% of men and 18% of women reported fantasies of sexual coercion, whereas 21% of men and 4% of women reported acts of sexual coercion. Moderated regression analyses showed that symptoms of depression as well as sexual coercive fantasies and behaviors were associated with levels of HD symptom severity. Problematic cybersex, total sexual outlet (TSO), pornography consumption, and number of sexual partners were also associated with HD symptom severity. Interaction effects indicated that, in women, the connection of TSO as well as pornography was more strongly associated with levels of HD symptom severity than in men. Conclusions This survey indicated that levels of HD symptom severity are often associated with severe intra- and interpersonal difficulties. Furthermore, the amount of sexual activity seems to be more strongly connected to levels of HD symptom severity in women than in men

Catching Element Formation In The Act

Gamma-ray astronomy explores the most energetic photons in nature to address some of the most pressing puzzles in contemporary astrophysics. It encompasses a wide range of objects and phenomena: stars, supernovae, novae, neutron stars, stellar-mass black holes, nucleosynthesis, the interstellar medium, cosmic rays and relativistic-particle acceleration, and the evolution of galaxies. MeV gamma-rays provide a unique probe of nuclear processes in astronomy, directly measuring radioactive decay, nuclear de-excitation, and positron annihilation. The substantial information carried by gamma-ray photons allows us to see deeper into these objects, the bulk of the power is often emitted at gamma-ray energies, and radioactivity provides a natural physical clock that adds unique information. New science will be driven by time-domain population studies at gamma-ray energies. This science is enabled by next-generation gamma-ray instruments with one to two orders of magnitude better sensitivity, larger sky coverage, and faster cadence than all previous gamma-ray instruments. This transformative capability permits: (a) the accurate identification of the gamma-ray emitting objects and correlations with observations taken at other wavelengths and with other messengers; (b) construction of new gamma-ray maps of the Milky Way and other nearby galaxies where extended regions are distinguished from point sources; and (c) considerable serendipitous science of scarce events -- nearby neutron star mergers, for example. Advances in technology push the performance of new gamma-ray instruments to address a wide set of astrophysical questions.Comment: 14 pages including 3 figure

Structures of Helicobacter pylori Shikimate Kinase Reveal a Selective Inhibitor-Induced-Fit Mechanism

Shikimate kinase (SK), which catalyzes the specific phosphorylation of the 3-hydroxyl group of shikimic acid in the presence of ATP, is the enzyme in the fifth step of the shikimate pathway for biosynthesis of aromatic amino acids. This pathway is present in bacteria, fungi, and plants but absent in mammals and therefore represents an attractive target pathway for the development of new antimicrobial agents, herbicides, and antiparasitic agents. Here we investigated the detailed structure–activity relationship of SK from Helicobacter pylori (HpSK). Site-directed mutagenesis and isothermal titration calorimetry studies revealed critical conserved residues (D33, F48, R57, R116, and R132) that interact with shikimate and are therefore involved in catalysis. Crystal structures of HpSK·SO4, R57A, and HpSK•shikimate-3-phosphate•ADP show a characteristic three-layer architecture and a conformationally elastic region consisting of F48, R57, R116, and R132, occupied by shikimate. The structure of the inhibitor complex, E114A•162535, was also determined, which revealed a dramatic shift in the elastic LID region and resulted in conformational locking into a distinctive form. These results reveal considerable insight into the active-site chemistry of SKs and a selective inhibitor-induced-fit mechanism

Lipids revert inert Aβ amyloid fibrils to neurotoxic protofibrils that affect learning in mice

Although soluble oligomeric and protofibrillar assemblies of Aβ-amyloid peptide cause synaptotoxicity and potentially contribute to Alzheimer's disease (AD), the role of mature Aβ-fibrils in the amyloid plaques remains controversial. A widely held view in the field suggests that the fibrillization reaction proceeds ‘forward' in a near-irreversible manner from the monomeric Aβ peptide through toxic protofibrillar intermediates, which subsequently mature into biologically inert amyloid fibrils that are found in plaques. Here, we show that natural lipids destabilize and rapidly resolubilize mature Aβ amyloid fibers. Interestingly, the equilibrium is not reversed toward monomeric Aβ but rather toward soluble amyloid protofibrils. We characterized these ‘backward' Aβ protofibrils generated from mature Aβ fibers and compared them with previously identified ‘forward' Aβ protofibrils obtained from the aggregation of fresh Aβ monomers. We find that backward protofibrils are biochemically and biophysically very similar to forward protofibrils: they consist of a wide range of molecular masses, are toxic to primary neurons and cause memory impairment and tau phosphorylation in mouse. In addition, they diffuse rapidly through the brain into areas relevant to AD. Our findings imply that amyloid plaques are potentially major sources of soluble toxic Aβ-aggregates that could readily be activated by exposure to biological lipids