AVALIAÇÃO EXPERIMENTAL E NUMÉRICA DA CINÉTICA DO CONGELAMENTO DO MÚSCULO DE ABRÓTEA (Urophycis brasiliensis)

This work carried out an experimental and numerical study of the kinetics of freezing of the Brazilian codling (Urophycis brasiliensis) muscle in air blast freezer, with air temperature set at 253.15 K and the average convective heat transfer coefficient at 25.4 W m-2 K-1. The initial temperature of the fish muscle was 277.15 K and the final temperature 255.15 K. The objective of this work was verify the best agreement between the experimental temperature profile and the numerical temperature profile to Brazilian codling muscle, using the CFD (Computational Fluid Dynamics) as numerical tool. In relation to the obtained results, it was verified that a good agreement between the experimental and numerical temperature profiles for the Brazilian codling muscle. The experimental freezing time found was 6618 s, and the freezing time through the numerical simulation was 6246 s. The error percentage found was 5.6%.Este trabalho realizou um estudo experimental e numérico da cinética de congelamento do músculo de abrótea (Urophycis brasiliensis) em uma câmara fria de convecção a ar forçado, com a temperatura do ar fixada em 253,15 K e o coeficiente convectivo médio de transferência de calor de 25,4 W m-2 K-1. A temperatura inicial do músculo do pescado foi de 277,15 K e a temperatura final de 255,15 K. O objetivo deste trabalho foi verificar a melhor concordância entre o perfil de temperatura experimental e o perfil de temperatura numérico para o músculo de abrótea, utilizando o CFD (Computational Fluid Dynamics) como ferramenta numérica. Em relação aos resultados obtidos, verificou-se uma boa concordância entre os perfis experimentais e numéricos de temperatura para o músculo de abrótea. O tempo de congelamento experimental encontrado foi de 6618 s, e o tempo de congelamento pela simulação numérica foi de 6246 s. O percentual de erro encontrado foi de 5,6%

AVALIAÇÃO DA FORÇA DE GEL DE SURIMI DE RESÍDUOS DE PESCADA-FOGUETE ( Macrodon ancylodon) ENRIQUECIDO COM ADITIVOS PROTÉICOS

Aditivos protéicos (albumina de soro bovino e clara de ovo) foram adicionados ao surimi de resíduos do processamento de pescada-foguete ( Macrodon ancylodon) para proteger a rede protéica miofibrilar e aumentar a força do gel kamaboko, formado durante o processamento térmico do surimi. Também adicionouse cloreto de amônio (NH4Cl) para inibir a transglutaminase, enzima cuja presença aumenta a textura devido melhor conformação das proteínas no pré-aquecimento. A análise instrumental em testes de compressão revelou que o surimi contendo aditivos alcançou maior força de gel em relação ao controle, sendo a albumina do soro bovino melhor do que a clara de ovo (

Rheological and physicochemical evaluation of thermal gelling of surimi from silver catfish

O objetivo deste trabalho foi avaliar as características reológicas e físico-químicas da gelificação térmica do surimi de jundiá (Rhamdia quelen). Utilizaram-se quatro tratamentos térmicos, três estágios duplos – pré-aquecimentos a 60oC durante 30, 45 e 60 min, seguidos de aquecimento a 90oC por 15 min, e um único aquecimento direto a 90oC por 15 min – e três formulações: duas com inibidores protéicos – soroalbumina bovina + alfa2-macroglobulina e clara de ovo – e uma sem inibidores. Amostras com inibidores protéicos e aquecimento direto alcançaram melhor gelificação, pelo incremento no módulo de elasticidade e decréscimo no ângulo de fase. Os géis pré-aquecidos apresentaram grande oscilação dos parâmetros viscoelásticos, o que comprometeu a formação da rede protéica tridimensional, formada durante a gelificação térmica do surimi. A concentração de peptídeos solúveis não sofreu alteração significativa, mesmo durante os estágios duplos, o que indica a ausência de proteólise, além de mostrar a proteção pelos inibidores à matriz protéica.The objective of this work was to evaluate the rheological and physicochemical properties of thermal gelling of surimi from silver catfish (Rhamdia quelen). Four heating treatments were used: one-step heating at 90oC, for 15 min, was compared with three two-step treatments with pre-heating at 60oC for 30, 45 and 60 min, followed by heating at 90oC for 15 min. Each heat treatment was used on three formulations: two with protease inhibitors (bovine serum albumin + alpha2-macroglobulin and egg white) and a formulation without inhibitors. Samples with inhibitors and one-step heating reached better gelling, by an increase in the storage modulus and a decrease in phase angle. Pre-heated gels had large variation in viscoelastic parameters which interfered with the establishment of the protein network during thermal gelling of surimi. The soluble peptides concentrations did not change significantly, even when two-step heating was carried out, which indicates absence of proteolysis, besides showing protein network protection by inhibitors

Avaliação reológica e físico‑química da gelificação térmica do surimi de jundiá

The objective of this work was to evaluate the rheological and physicochemical properties of thermal gelling of surimi from silver catfish (Rhamdia quelen). Four heating treatments were used: one-step heating at 90oC, for 15 min, was compared with three two-step treatments with pre-heating at 60oC for 30, 45 and 60 min, followed by heating at 90oC for 15 min. Each heat treatment was used on three formulations: two with protease inhibitors (bovine serum albumin + alpha2-macroglobulin and egg white) and a formulation without inhibitors. Samples with inhibitors and one-step heating reached better gelling, by an increase in the storage modulus and a decrease in phase angle. Pre-heated gels had large variation in viscoelastic parameters which interfered with the establishment of the protein network during thermal gelling of surimi. The soluble peptides concentrations did not change significantly, even when two-step heating was carried out, which indicates absence of proteolysis, besides showing protein network protection by inhibitors.O objetivo deste trabalho foi avaliar as características reológicas e físico-químicas da gelificação térmica do surimi de jundiá (Rhamdia quelen). Utilizaram-se quatro tratamentos térmicos, três estágios duplos – pré-aquecimentos a 60oC durante 30, 45 e 60 min, seguidos de aquecimento a 90oC por 15 min, e um único aquecimento direto a 90oC por 15 min – e três formulações: duas com inibidores protéicos – soroalbumina bovina + alfa2-macroglobulina e clara de ovo – e uma sem inibidores. Amostras com inibidores protéicos e aquecimento direto alcançaram melhor gelificação, pelo incremento no módulo de elasticidade e decréscimo no ângulo de fase. Os géis pré-aquecidos apresentaram grande oscilação dos parâmetros viscoelásticos, o que comprometeu a formação da rede protéica tridimensional, formada durante a gelificação térmica do surimi. A concentração de peptídeos solúveis não sofreu alteração significativa, mesmo durante os estágios duplos, o que indica a ausência de proteólise, além de mostrar a proteção pelos inibidores à matriz protéica

PTF11rka: an interacting supernova at the crossroads of stripped-envelope and H-poor superluminous stellar core collapses

The hydrogen-poor supernova PTF11rka (z = 0.0744), reported by the Palomar Transient Factory, was observed with various telescopes starting a few days after the estimated explosion time of 2011 Dec. 5 UT and up to 432 rest-frame days thereafter. The rising part of the light curve was monitored only in the R_PTF filter band, and maximum in this band was reached ~30 rest-frame days after the estimated explosion time. The light curve and spectra of PTF11rka are consistent with the core-collapse explosion of a ~10 Msun carbon-oxygen core evolved from a progenitor of main-sequence mass 25--40 Msun, that liberated a kinetic energy (KE) ~ 4 x 10^{51} erg, expelled ~8 Msun of ejecta (Mej), and synthesised ~0.5 Msun of 56Nichel. The photospheric spectra of PTF11rka are characterised by narrow absorption lines that point to suppression of the highest ejecta velocities ~>15,000 km/s. This would be expected if the ejecta impacted a dense, clumpy circumstellar medium. This in turn caused them to lose a fraction of their energy (~5 x 10^50 erg), less than 2% of which was converted into radiation that sustained the light curve before maximum brightness. This is reminiscent of the superluminous SN 2007bi, the light-curve shape and spectra of which are very similar to those of PTF11rka, although the latter is a factor of 10 less luminous and evolves faster in time. PTF11rka is in fact more similar to gamma-ray burst supernovae (GRB-SNe) in luminosity, although it has a lower energy and a lower KE/Mej ratio

Should Research Ethics Encourage the Production of Cost-Effective Interventions?

This project considers whether and how research ethics can contribute to the provision of cost-effective medical interventions. Clinical research ethics represents an underexplored context for the promotion of cost-effectiveness. In particular, although scholars have recently argued that research on less-expensive, less-effective interventions can be ethical, there has been little or no discussion of whether ethical considerations justify curtailing research on more expensive, more effective interventions. Yet considering cost-effectiveness at the research stage can help ensure that scarce resources such as tissue samples or limited subject popula- tions are employed where they do the most good; can support parallel efforts by providers and insurers to promote cost-effectiveness; and can ensure that research has social value and benefits subjects. I discuss and rebut potential objections to the consideration of cost-effectiveness in research, including the difficulty of predicting effectiveness and cost at the research stage, concerns about limitations in cost-effectiveness analysis, and worries about overly limiting researchers’ freedom. I then consider the advantages and disadvantages of having certain participants in the research enterprise, including IRBs, advisory committees, sponsors, investigators, and subjects, consider cost-effectiveness. The project concludes by qualifiedly endorsing the consideration of cost-effectiveness at the research stage. While incorporating cost-effectiveness considerations into the ethical evaluation of human subjects research will not on its own ensure that the health care system realizes cost-effectiveness goals, doing so nonetheless represents an important part of a broader effort to control rising medical costs

Observational and Physical Classification of Supernovae

This chapter describes the current classification scheme of supernovae (SNe). This scheme has evolved over many decades and now includes numerous SN Types and sub-types. Many of these are universally recognized, while there are controversies regarding the definitions, membership and even the names of some sub-classes; we will try to review here the commonly-used nomenclature, noting the main variants when possible. SN Types are defined according to observational properties; mostly visible-light spectra near maximum light, as well as according to their photometric properties. However, a long-term goal of SN classification is to associate observationally-defined classes with specific physical explosive phenomena. We show here that this aspiration is now finally coming to fruition, and we establish the SN classification scheme upon direct observational evidence connecting SN groups with specific progenitor stars. Observationally, the broad class of Type II SNe contains objects showing strong spectroscopic signatures of hydrogen, while objects lacking such signatures are of Type I, which is further divided to numerous subclasses. Recently a class of super-luminous SNe (SLSNe, typically 10 times more luminous than standard events) has been identified, and it is discussed. We end this chapter by briefly describing a proposed alternative classification scheme that is inspired by the stellar classification system. This system presents our emerging physical understanding of SN explosions, while clearly separating robust observational properties from physical inferences that can be debated. This new system is quantitative, and naturally deals with events distributed along a continuum, rather than being strictly divided into discrete classes. Thus, it may be more suitable to the coming era where SN numbers will quickly expand from a few thousands to millions of events.Comment: Extended final draft of a chapter in the "SN Handbook". Comments most welcom

Carcass conformation and fat cover scores in beef cattle: A comparison of threshold linear models vs grouped data models

Background: Beef carcass conformation and fat cover scores are measured by subjective grading performed by trained technicians. The discrete nature of these scores is taken into account in genetic evaluations using a threshold model, which assumes an underlying continuous distribution called liability that can be modelled by different methods. Methods: Five threshold models were compared in this study: three threshold linear models, one including slaughterhouse and sex effects, along with other systematic effects, with homogeneous thresholds and two extensions with heterogeneous thresholds that vary across slaughterhouses and across slaughterhouse and sex and a generalised linear model with reverse extreme value errors. For this last model, the underlying variable followed a Weibull distribution and was both a log-linear model and a grouped data model. The fifth model was an extension of grouped data models with score-dependent effects in order to allow for heterogeneous thresholds that vary across slaughterhouse and sex. Goodness-of-fit of these models was tested using the bootstrap methodology. Field data included 2,539 carcasses of the Bruna dels Pirineus beef cattle breed. Results: Differences in carcass conformation and fat cover scores among slaughterhouses could not be totally captured by a systematic slaughterhouse effect, as fitted in the threshold linear model with homogeneous thresholds, and different thresholds per slaughterhouse were estimated using a slaughterhouse-specific threshold model. This model fixed most of the deficiencies when stratification by slaughterhouse was done, but it still failed to correctly fit frequencies stratified by sex, especially for fat cover, as 5 of the 8 current percentages were not included within the bootstrap interval. This indicates that scoring varied with sex and a specific sex per slaughterhouse threshold linear model should be used in order to guarantee the goodness-of-fit of the genetic evaluation model. This was also observed in grouped data models that avoided fitting deficiencies when slaughterhouse and sex effects were score-dependent. Conclusions: Both threshold linear models and grouped data models can guarantee the goodness-of-fit of the genetic evaluation for carcass conformation and fat cover, but our results highlight the need for specific thresholds by sex and slaughterhouse in order to avoid fitting deficiencies

Evidence for negative selection of gene variants that increase dependence on dietary choline in a Gambian cohort

Choline is an essential nutrient, and the amount needed in the diet is modulated by several factors. Given geographical differences in dietary choline intake and disparate frequencies of single-nucleotide polymorphisms (SNPs) in choline metabolism genes between ethnic groups, we tested the hypothesis that 3 SNPs that increase dependence on dietary choline would be under negative selection pressure in settings where choline intake is low: choline dehydrogenase (CHDH) rs12676, methylenetetrahydrofolate reductase 1 (MTHFD1) rs2236225, and phosphatidylethanolamine-N-methyltransferase (PEMT) rs12325817. Evidence of negative selection was assessed in 2 populations: one in The Gambia, West Africa, where there is historic evidence of a choline-poor diet, and the other in the United States, with a comparatively choline-rich diet. We used 2 independent methods, and confirmation of our hypothesis was sought via a comparison with SNP data from the Maasai, an East African population with a genetic background similar to that of Gambians but with a traditional diet that is higher in choline. Our results show that frequencies of SNPs known to increase dependence on dietary choline are significantly reduced in the low-choline setting of The Gambia. Our findings suggest that adequate intake levels of choline may have to be reevaluated in different ethnic groups and highlight a possible approach for identifying novel functional SNPs under the influence of dietary selective pressure