1,333 research outputs found
The geometry of null rotation identifications
The geometry of flat spacetime modded out by a null rotation (boost+rotation)
is analysed. When embedding this quotient spacetime in String/M-theory, it
still preserves one half of the original supersymmetries. Its connection with
the BTZ black hole, supersymmetric dilatonic waves and one possible resolution
of its singularity in terms of nullbranes are also discussed.Comment: 1+18 pages, 5 figures. v2 references adde
A small universe after all?
The cosmic microwave background radiation allows us to measure both the
geometry and topology of the universe. It has been argued that the COBE-DMR
data already rule out models that are multiply connected on scales smaller than
the particle horizon. Here we show the opposite is true: compact (small)
hyperbolic universes are favoured over their infinite counterparts. For a
density parameter of Omega_o=0.3, the compact models are a better fit to
COBE-DMR (relative likelihood ~20) and the large-scale structure data (sigma_8
increases by ~25%).Comment: 4 pages, RevTeX, 7 Figure
Dasyatidae no Cretáceo da Amazônia Oriental: considerações paleoecológicas
O Grupo Itapecuru teve sua origem ligada à ruptura em zonas de tensão e transcorrência associada ao desenvolvimento de rift intracontinental durante a separação dos continentes africano e sul-americano. Estes depósitos contêm uma diversidade de ambientes deposicionais, como canais fluviais, lagunas, canais de maré, estuarino-lagunares e marinhos rasos, cuja reconstituição pode ser auxiliada pelo seu conteúdo paleontológico. Amostras de peixes fósseis provenientes de depósitos albianos do Grupo Itapecuru no Município de Codó, Maranhão, possibilitaram a recuperação de 4 dentes identificados como pertencentes a arraias da família Dasyatidae. Estes apresentam coroa molariforme elíptica, típica de dentição para esmagamento, com tamanhos variando entre 1mm à 3mm de comprimento, e 1mm de largura. Dentes fósseis pertencentes a esta família já haviam sido associados a ambientes de canais e depósitos com influência de maré, incluindo ambientes restritos como o estuarino ocorrentes em depósitos cretáceos de outras regiões. No caso do registro de Codó, esta ocorrência confirmaria a descrição paleoambiental existente para o Grupo.Sesiones libresFacultad de Ciencias Naturales y Muse
Psychoeducational intervention for people at high risk of developing another melanoma: a pilot randomised controlled trial
Introduction Information and psychological needs have been reported as one of the greatest areas of unmet needs for patients with melanoma. To respond to these needs, we developed the Melanoma Care Intervention, a developed psychoeducational intervention for people at high risk of developing another melanoma comprising of a newly developed melanoma educational booklet and individually tailored telephone support sessions provided by trained psychologists. The purpose of this study was to investigate the acceptability and feasibility of the Melanoma Care Intervention.
Methods Twenty-four adults (14 men, 10 women, mean age: 58 years, SD: 12.2) at high risk of developing a subsequent primary melanoma were recruited and randomly assigned 1:1 to the intervention (a psychoeducational booklet, a Cancer Council booklet on melanoma and up to five telephone-based sessions with a psychologist) or usual care (Cancer Council booklet only). Acceptability, feasibility, fear of cancer recurrence and secondary psychosocial outcomes were assessed at baseline, 1 and 6 months.
Results Satisfaction and perceived benefits were rated highly for all intervention components, particularly the telephone-based psychology sessions (mean satisfaction and benefits: both 9.27 out of 10, SD=2.41). The quality of information and support provided throughout the trial was rated as ‘high’ by the intervention group, with a mean score of 4.6 out of a possible 5 (SD=0.9) and 4.2 (SD=1.2) for the control group.
Conclusions The intervention was feasible and acceptable for improving psychological adjustment. Timely access to effective, evidence-based, psychological care is a recognised need for people with melanoma. The intervention is designed to directly address this need in a way that is feasible in a clinical setting, acceptable to patients and health professionals
April - An inductive logic programming system
Inductive Logic Programming (ILP) is a Machine Learning research field that has been quite successful in knowledge discovery in relational domains. ILP systems use a set of pre-classified examples (positive and negative) and prior knowledge to learn a theory in which positive examples succeed and the negative examples fail. In this paper we present a novel ILP system called April, capable of exploring several parallel strategies in distributed and shared memory machines
Educação e trabalho na perspectiva da formação continuada do profissional não-docente das IES / Education and work in the perspective of continuing education for non-teaching professionals in HEIs
O estudo visa refletir sobre as categorias educação e trabalho na perspectiva da formação continuada dos profissionais não-docentes que atuam de modo invisibilizado nas Instituições de Ensino Superior públicas do Brasil (IES), sem terem a oportunidade de usufruírem daquilo que essas mesmas profetizam: uma educação de qualidade, emancipadora, capaz de despertar no sujeito ações que promovam a crítica necessária ao modo de reprodução exploratório do modelo capitalista, pela via do conhecimento científico. A metodologia, pesquisa qualitativa e bibliográfica, deve-se aos estudos teóricos realizados recentemente por ocasião da nossa formação continuada e pauta-se no materialismo histórico a partir de autores como Antunes (2012), Mészáros (2008), Paro (2013) e algumas Legislações pertinentes. Os resultados apontam que cabe a essa categoria de trabalhadores, os profissionais não-docentes aqui entendidos como os técnicos administrativos que atuam nas IES, enquanto sujeitos partícipes do processo educativo regulamentado por essas Instituições, envidarem esforços no sentido de que as ações de formação continuada, em todos os níveis da educação formal, sejam bandeiras de luta de modo a proporcionar a materialização de Planos de Capacitação que contemplem a aspiração acadêmica destes profissionais, para além do desenvolvimento de competências e habilidades profissionais propícias ao produtivismo e, consequentemente, a alienação do trabalho. As conclusões apontam que na condição de sujeitos pensantes, deseja-se que estes profissionais consigam superar a alienação imposta pelo Capitalismo, transformados pela ação emancipadora do trabalho produtivo, na perspectiva da ressignificação de sua atuação, de forma que efetivamente possam contribuir para que a educação, entendida em seu sentido mais amplo, seja um instrumento de transformação social para o outro e para si.
Development of β-TCP-Ti6Al4V structures: Driving cellular response by modulating physical and chemical properties
Acknowledgments
This work was supported by FCT (Fundação para a Ciência e Tecnologia) through the grants SFRH/BD/140191/2018; SFRH/BPD/112111/2015, SFRH/BD/128657/2017, SFRH/BD/141056/2018; SFRH/BPD/97701/2013, PD/BDE/127836/2016, and the projects PTDC/EMS-TEC/5422/2014_ADAPTPROSTHESIS and NORTE-01-
0145-FEDER-000018-HAMaBICo. Additionally, this work was supported by FCT with the reference project UID/EEA/04436/2013, by FEDER funds through the COMPETE 2020 – Programa Operacional Competitividade e Internacionalização (POCI) with the reference project POCI-01-0145-FEDER-006941.Load-bearing implants success is strongly dependent on several physical and chemical properties that are known to drive cellular response. In this work, multi-material β-TCP-Ti6Al4V cellular structures were designed to combine Ti6Al4V mechanical properties and β-Tricalcium Phosphate bioactivity, in order to promote bone ingrowth as the bioactive material is being absorbed and replaced by newly formed bone. In this sense, the produced structures were characterized regarding roughness, wettability, β-TCP quantity and quality inside the structures after fabrication and the pH measured during cell culture (as consequence of β-TCP dissolution) and those aspects were correlated with cellular viability, distribution, morphology and proliferation. These structures displayed a hydrophilic behavior and results showed that the addition of β-TCP to these
cellular structures led to an alkalization of the medium, aspect that significantly influences the cellular response. Higher impregnation ratios were found more adequate for lowering the media pH and toxicity, and thus enhance cell adhesion and proliferation.info:eu-repo/semantics/publishedVersio
45S5 BAG-Ti6Al4V structures: The influence of the design on some of the physical and chemical interactions that drive cellular response
This work was supported by FCT (Fundação para a Ciência e Tecnologia) through the grants SFRH/BPD/112111/2015, SFRH/BD/128657/2017, PD/BDE/127836/2016, SFRH/BPD/97701/2013, SFRH/
BD/141056/2018, SFRH/BD/140191/2018 and the projects PTDC/EMSTEC/5422/2014 and NORTE-01-0145-FEDER-000018-HAMaBICo. Additionally, this work was supported by FCT with the reference project
UID/EEA/04436/2013, by FEDER funds through the COMPETE 2020 – Programa Operacional Competitividade e Internacionalização (POCI) with the reference project POCI-01-0145-FEDER-006941.Multi-material Ti6Al4V cellular structures impregnated with 45S5 bioactive glass were designed and produced
using Selective LaserMelting (SLM), an additive manufacturing technique, combinedwith Press and Sintering focusing on load bearing components like hip implants. These structures were designed to combine Ti6Al4V mechanical properties and promote bone ingrowth into the structure as the bioactive material (45S5) is being
absorbed and replaced by newly formed bone. The influence of these structures design on some of the physical and chemical aspects that drive cellular response was assessed. Roughness, wettability, bioactive glass quantity and quality on the structures after processing and the pH measured during cell culture (as a consequence of bioactive glass dissolution) were evaluated and correlated with cellular viability, cellular distribution, morphology and proliferation on the surface and inside the structures.info:eu-repo/semantics/publishedVersio
ERP correlates of error processing during performance on the HalsteadCategory Test
The Halstead Category Test (HCT) is a neuropsychological test that measures a person's ability to formulate and
apply abstract principles. Performance must be adjusted based on feedback after each trial and errors are
common until the underlying rules are discovered. Event-related potential (ERP) studies associated with the HCT
are lacking. This paper demonstrates the use of amethodology inspired on Singular SpectrumAnalysis (SSA) applied
to EEG signals, to remove high amplitude ocular andmovement artifacts during performance on the test. This filtering
technique introduces no phase or latency distortions, with minimum loss of relevant EEG information. Importantly,
the test was applied in its original clinical format, without introducing adaptations to ERP recordings. After
signal treatment, the feedback-related negativity (FRN) wave, which is related to error-processing, was identified.
This component peaked around 250ms, after feedback, in fronto-central electrodes. As expected, errors elicited
more negative amplitudes than correct responses. Results are discussed in terms of the increased clinical potential
that coupling ERP informationwith behavioral performance data can bring to the specificity of theHCT in diagnosing
different types of impairment in frontal brain function.info:eu-repo/semantics/publishedVersio
Família Characidae na Formação Pirabas (Eomioceno), Amazônia Oriental: implicações paleoambientais
A Formação Pirabas ocorre em bacias sedimentares localizadas ao longo da costa norte brasileira, tendo no litoral nordeste do Estado do Pará sua maior representatividade em superfície. Esta unidade foi formada em diversos ambientes deposicionais, principalmente incluindo plataforma externa, plataforma restrita e complexo de ilhasbarreira com canais, planícies e deltas de maré, além de laguna e manguezais. Entre os fósseis encontrados, os peixes merecem destaque pela abundância, diversidade e representatividade geográfica e temporal, características que elevam seu potencial de utilização em estudos paleoambientais e estratigráficos. A paleoictiofauna documentada para esta unidade consiste, exclusivamente, de grupos pertencentes a ambientes marinhos. Estudos recentes vêm aumentando a recuperação de fósseis de peixes por meio de lavagem por peneiramento. Esta metodologia tem resultado em um volume elevado de microdentes o que, juntamente com estudos estratigráficos, contribui para auxiliar no refinamento de interpretações paleoambientais. A utilização desta técnica resultou na recuperação de 7 dentes atribuídos a Characidae em diferentes níveis estratigráficos ao longo de um mesmo perfil de 7m de espessura registrado na localidade de Capanema, Estado do Pará. Na base deste perfil, os dentes ocorrem em fácies de calcário clástico contendo fragmentos de invertebrados fósseis. Estes depósitos, de base ligeiramente côncava e erosiva, estão organizados em granodecrescência ascendente, o que sugere retrabalhamento por fluxos confinados em ambientes canalizados. Adicionalmente, dentes fósseis desta família foram recuperados de argilitos intercalados com depósitos heterolíticos formando pacotes tabulares e lateralmente contínuos, que são interpretados como representativos de ambientes de laguna e planície de maré. O registro inédito desta família na Formação Pirabas aumenta o número de táxons de ictiofósseis até então descritos para esta unidade, além de servir como indicador de períodos com forte influência de influxos fluviais, provavelmente relacionados com momentos de recuo da linha da costa.Sesiones libresFacultad de Ciencias Naturales y Muse
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