11,829 research outputs found
Antihyperon polarization in high-energy inclusive reactions
We propose a model for the antihyperon polarization in high-energy
proton-nucleus inclusive reactions, based on the final-state interactions
between the antihyperons and other produced particles (predominantly pions). To
formulate this idea, we use the previously obtained low-energy
pion-(anti-)hyperon interaction using effective chiral Lagrangians, and a
hydrodynamic parametrization of the background matter, which expands and
decouples at a certain freezeout temperature.Comment: 17 pages, 10 figure
P-248 Futility and utility of two-stage hepatectomy
Meeting abstract in the European-Society-for-Medical-Oncology (ESMO) 21st World Congress on Gastrointestinal Cancer.info:eu-repo/semantics/publishedVersio
Optimal switching of a nanomagnet assisted by microwaves
We develop an efficient and general method for optimizing the microwave field
that achieves magnetization switching with a smaller static field. This method
is based on optimal control and renders an exact solution for the 3D microwave
field that triggers the switching of a nanomagnet with a given anisotropy and
in an oblique static field. Applying this technique to the particular case of
uniaxial anisotropy, we show that the optimal microwave field, that achieves
switching with minimal absorbed energy, is modulated both in frequency and in
magnitude. Its role is to drive the magnetization from the metastable
equilibrium position towards the saddle point and then damping induces the
relaxation to the stable equilibrium position. For the pumping to be efficient,
the microwave field frequency must match at the early stage of the switching
process the proper precession frequency of the magnetization, which depends on
the magnitude and direction of the static field. We investigate the effect of
the static field (in amplitude and direction) and of damping on the
characteristics of the microwave field. We have computed the switching curves
in the presence of the optimal microwave field. The results are in qualitative
agreement with micro-SQUID experiments on isolated nanoclusters. The strong
dependence of the microwave field and that of the switching curve on the
damping parameter may be useful in probing damping in various nanoclusters.Comment: 9 pages, 8 figure
Heterotrophy as a tool to overcome the long and costly autotrophic scale-up process for large scale production of microalgae
Industrial scale-up of microalgal cultures is often a protracted step prone to culture collapse and the occurrence of unwanted contaminants. To solve this problem, a two-stage scale-up process was developed - heterotrophically Chlorella vulgaris cells grown in fermenters (1st stage) were used to directly inoculate an outdoor industrial autotrophic microalgal production unit (2nd stage). A preliminary pilot-scale trial revealed that C. vulgaris cells grown heterotrophically adapted readily to outdoor autotrophic growth conditions (1-m3 photobioreactors) without any measurable difference as compared to conventional autotrophic inocula. Biomass concentration of 174.5 g L-1, the highest value ever reported for this microalga, was achieved in a 5-L fermenter during scale-up using the heterotrophic route. Inocula grown in 0.2- and 5-m3 industrial fermenters with mean productivity of 27.54 ± 5.07 and 31.86 ± 2.87 g L-1 d-1, respectively, were later used to seed several outdoor 100-m3 tubular photobioreactors. Overall, all photobioreactor cultures seeded from the heterotrophic route reached standard protein and chlorophyll contents of 52.18 ± 1.30% of DW and 23.98 ± 1.57 mg g-1 DW, respectively. In addition to providing reproducible, high-quality inocula, this two-stage approach led to a 5-fold and 12-fold decrease in scale-up time and occupancy area used for industrial scale-up, respectively.Agência financiadora
project FERMALG
017608
Fundacao para a Ciencia e a Tecnologia (FCT)
UID/Multi/04326/2019
project FERMALG (AVISO)
32/SI/2015info:eu-repo/semantics/publishedVersio
On the stability of spacelike hypersurfaces
In this paper we study the strong stability of spacelike hypersurfaces with
constant -th mean curvature in Generalized Robertson-Walker spacetimes of
constant sectional curvature. In particular, we treat the case in which the
ambient spacetime is the de Sitter space
Perspectivas sobre o acesso aos tratamentos de fertilidade em Portugal
OBJECTIVE: To analyze users' reasons for choosing in vitro fertilization treatment in public or private services and to identify their suggestions for improving fertility treatment. METHODS: A qualitative study using an interpretative approach was conducted. Fifteen semi-structured interviews were conducted with patients undergoing in vitro fertilization treatment (nine women, one man and five couples) at home or at their workplace in the districts of Viana do Castelo, Braga, Porto and Lisbon, Portugal, between July 2005 and February 2006. RESULTS: Users evaluated access to in vitro fertilization treatment in public and private services based mainly on their individual experiences and called for more access to less costly, faster and friendlier care with suitable facilities, appropriate time management and caring medical providers. These perceptions were also associated with views on the need for fighting stigmatization of infertility, protecting children's rights and guaranteeing sustainability of health care system. Interviewees sought to balance reduced waiting time and more attentive care with costs involved. The choice of services depended on the users' purchase power and place of residence and availability of attentive care. CONCLUSIONS: Current national policies on in vitro fertilization treatment meet user's demands of promoting access to, and quality, availability and affordability of in vitro fertilization treatment. However, their focus on legal regulation and technical-scientific aspects contrasts with the users' emphasis on reimbursement, insurance coverage and focus on emotional aspects of the treatment. The study showed these policies should ensure insurance coverage, participation of user representatives in the National Council for Assisted Reproductive Technology, promotion of infertility research and certification of fertility laboratories.OBJETIVO: Analizar las motivaciones de usuarios para escogencia de tratamientos de fertilización in vitro en servicios públicos y privados e identificar propuestas que mejoren la calidad de los mismos. MÉTODOS: Estudio cualitativo con abordaje interpretativa, basado en 15 entrevistas semi-estructuradas con personas que intentaron concebir por medio de técnicas de procreación con asistencia médica en Portugal (nueve mujeres, un hombre y cinco matrimonios). Las entrevistas fueron realizadas entre julio de 2005 y febrero de 2006 en los distritos de Viana do Castelo, Braga, Porto y Lisboa, en casa o en el lugar de trabajo de los entrevistados. RESULTADOS: Los usuarios evaluaron el acceso a los tratamientos de fertilidad en el servicio público o privado principalmente con base en sus experiencias individuales, reclamando acceso más barato, rápido y amigable, en espacios adecuados, con gestión apropiada de los tiempos de espera y servicios médicos atentos. Tales percepciones fueron asociadas a visiones sobre la necesidad de combatir la estigmatización de infertilidad y defender los derechos del niño y la sustentabilidad del sistema de salud. Los entrevistados buscaron equilibrar la reducción del tiempo de espera y cuidados más atentos con los costos financieros involucrados. La escogencia de los servicios dependió del capital económico y del lugar de residencia de los utilizadores y de la existencia de cuidados atentos CONCLUSIONES: Las actuales políticas nacionales van en paralelo con las expectativas de los utilizadores al promover el acceso a los tratamientos de fertilidad y su calidad, pero se separan de ellas al enfatizar la regulación jurídico-legal y la dimensión técnico-científica de la calidad en la procreación con asistencia médica en detrimento de la activación de seguros de salud y de la valorización de aspectos emocionales. Las políticas a implementar pasan por la cobertura obligatoria de los tratamientos por los seguros de salud, la inclusión de un representante de los utilizadores en el Consejo Nacional de Procreación Con Asistencia Médica, la promoción de la investigación sobre infertilidad en Portugal y la certificación de los laboratorios que realizan pruebas de fertilidad.OBJETIVO: Analisar as motivações para escolha de tratamentos de fertilização in vitro em serviços públicos e privados, bem como identificar propostas que melhorem a qualidade desses. MÉTODOS: Estudo qualitativo e interpretativo, baseado em 15 entrevistas semiestruturadas com pessoas que tentaram conceber por meio de técnicas de procriação medicamente assistida em Portugal (nove mulheres, um homem e cinco casais). As entrevistas foram realizadas entre julho de 2005 e fevereiro de 2006 nos distritos de Viana do Castelo, Braga, Porto e Lisboa, em casa ou no local de trabalho dos entrevistados. RESULTADOS: Os usuários avaliaram o acesso aos tratamentos de fertilidade no serviço público ou privado sobretudo com base nas suas experiências individuais, reclamando acesso mais barato, rápido e amigável, em espaços adequados, com gestão apropriada dos tempos de espera e serviços médicos atenciosos. Tais percepções foram associadas a visões sobre a necessidade de combater a estigmatização da infertilidade e defender os direitos da criança e a sustentabilidade do sistema de saúde. Os entrevistados procuraram equilibrar a redução do tempo de espera e cuidados mais atenciosos com os custos envolvidos. A escolha dos serviços dependeu da renda e do local de residência dos usuários, além da existência de cuidados atenciosos. CONCLUSÕES: As atuais políticas nacionais vão ao encontro das expetativas dos utilizadores ao promover o acesso aos tratamentos de fertilidade e a sua qualidade, mas distanciam-se delas ao enfatizarem a regulação jurídico-legal e a dimensão técnico-científica da qualidade na procriação medicamente assistida em detrimento do acionamento de seguros de saúde e da valorização de aspetos emocionais. As políticas a implementar passam pela cobertura obrigatória dos tratamentos pelos seguros de saúde, pela inclusão de um representante dos usuários no Conselho Nacional de Procriação Medicamente Assistida, pela promoção da investigação sobre infertilidade em Portugal e pela certificação dos laboratórios que realizam testes de fertilidade
A scoping review on sexual and reproductive health behaviors among Tanzanian adolescents
Background There is wide variation among societies in profiles of adolescent health and behaviors, but they all experience sexual and reproductive health as a major challenge. However, adolescents in middle- and low-income countries are of particular concern, as it is the case in Tanzania, where limited social, educational, and health services contribute to make them victims of unwanted pregnancies, unsafe abortion, and sexually transmitted infections including HIV. Thus, we undertook a descriptive systematic scoping review of the available published information on sexual and reproductive health among Tanzanian adolescents. Methods We performed a scoping review to collect and analyze observational data on sexual and reproductive health behaviors among Tanzanian adolescents. Publications were identified using PubMed (R), Scopus (R), Web of Science (TM), and Cochrane Library electronic databases from 2000 to December 2017. A protocol was defined to identify relevant studies. We included original observational studies conducted in Tanzania and published in English, both quantitative and qualitative, involving adolescents (10 to 19 years old), and that considered at least one of the following items: condom use, number of sexual partners, sexual debut, contraceptive prevalence, sexually transmitted infections, unwanted pregnancies, abortion, or knowledge about reproductive health. All included articles were coded according to relevant exposures or outcomes and subsequently analyzed to assess frequencies. Results After screening for inclusion criteria, 13 publications were included in the datasheet developed to record the findings. Overall, the publications revealed that adolescents tend to be sexually active, with high rates of early sexual debut, have multiple sexual partners, and a limited use of condom and contraceptives. Sexual coercion and transactional sex were also frequent. Only one study addressed pregnancy as an outcome, and a single study looked at the relevant health services. No study was retrieved describing the frequency of unsafe abortion. Conclusion Adolescents engage in high-risk sexual behaviors and experience its adverse consequences. It is essential to collect more information, but the existing evidence supports a need for improving provision of sexual and reproductive health services among Tanzanian adolescents.This study was funded by FEDER through the Operational Programme Competitiveness and Internationalization and national funding from the Foundation for Science and Technology - FCT (Portuguese Ministry of Science, Technology and Higher Education) under the Unidade de Investigacao em Epidemiologia - Instituto de Saude Publica da Universidade do Porto (EPIUnit) (POCI-01-0145-FEDER-006862; Ref. UID/DTP/04750/2013). HN received a PhD grant from FCT: PD/BD/105826/2014
Seismic strengthening of beam-column joints with multidirectional CFRP laminates
An experimental program was carried out to analyse the potentialities of a technique based on the use of multidirectional CFRP laminates (MDL-CFRP) for the seismic repair and strengthening of reinforced concrete (RC) beam-column joints. This experimental program comprises cyclic tests on three full-scale RC joints, representative of interior beam-column connections in buildings. The joints were initially submitted to a cyclic test inducing a
damage pattern representative of a seismic event. Subsequently, they were repaired and
strengthened with MDL-CFRP. The strengthened joints were then tested for the same loading
history of the original ones up to their failure. The adopted strengthening technique uses the MDL-CFRP that are simultaneously glued and anchored to the concrete surfaces. This technique is called Mechanically Fastened and Externally Bonded Reinforcement (MF-EBR).
In the present study, the effectiveness of two different strengthening configurations was investigated. The tests are described and the main results are presented and analyzed
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