A Model of the Cellular Iron Homeostasis Network Using Semi-Formal Methods for Parameter Space Exploration

This paper presents a novel framework for the modeling of biological networks. It makes use of recent tools analyzing the robust satisfaction of properties of (hybrid) dynamical systems. The main challenge of this approach as applied to biological systems is to get access to the relevant parameter sets despite gaps in the available knowledge. An initial estimate of useful parameters was sought by formalizing the known behavior of the biological network in the STL logic using the tool Breach. Then, once a set of parameter values consistent with known biological properties was found, we tried to locally expand it into the largest possible valid region. We applied this methodology in an effort to model and better understand the complex network regulating iron homeostasis in mammalian cells. This system plays an important role in many biological functions, including erythropoiesis, resistance against infections, and proliferation of cancer cells.Comment: In Proceedings HSB 2012, arXiv:1208.315

Vartaloallomorfien myönteinen vaikutus sanojen tunnistamiseen

The aim of the present study was to investigate whether the recognition speed of Finnish nominal base forms varies as a function of their paradigmatic complexity (stem allomorphy) or productivity status. Nikolaev et al. (2014) showed that words with greater stem allomorphy from an unproductive inflectional class arc recognized faster than words with lower stein allomorphy from a productive inflectional class. Productivity of an inflectional paradigm correlates with the number of stem allomorphs in languages like Finnish in that unproductive inflectional classes tend to have higher stem allomorphy. We wanted to distinguish which of these two characteristics provides the benefit to speed of recognition found by Nikolaev et al. (2014). The current study involved a lexical decision task comparing three categories of words: unproductive with three or more stem allomorphs, unproductive with two stem allomorphs, and productive with two stein allomorphs. We observed a facilitation effect for word recognition only for unproductive words with three or more stem allomorphs, but not for unproductive words with two allomorphs. This effect was observed particularly in words of low to moderate familiarity. The findings suggest that high stem allomorphy, rather than productivity of the inflectional class, is driving the facilitation effect in word recognition.Peer reviewe

Stringent Limits on the Polarized Submillimeter Emission from Protoplanetary Disks

We present arcsecond-resolution Submillimeter Array (SMA) polarimetric observations of the 880 um continuum emission from the protoplanetary disks around two nearby stars, HD 163296 and TW Hydrae. Although previous observations and theoretical work have suggested that a 2-3% polarization fraction should be common for the millimeter continuum emission from such disks, we detect no polarized continuum emission above a 3-sigma upper limit of 7 mJy in each arcsecond-scale beam, or <1% in integrated continuum emission. We compare the SMA upper limits with the predictions from the exploratory Cho & Lazarian (2007) model of polarized emission from T Tauri disks threaded by toroidal magnetic fields, and rule out their fiducial model at the ~10-sigma level. We explore some potential causes for this discrepancy, focusing on model parameters that describe the shape, magnetic field alignment, and size distribution of grains in the disk. We also investigate related effects like the magnetic field strength and geometry, scattering off of large grains, and the efficiency of grain alignment, including recent advances in grain alignment theory, which are not considered in the fiducial model. We discuss the impact each parameter would have on the data and determine that the suppression of polarized emission plausibly arises from rounding of large grains, reduced efficiency of grain alignment with the magnetic field, and/or some degree of magnetic field tangling (perhaps due to turbulence). A poloidal magnetic field geometry could also reduce the polarization signal, particularly for a face-on viewing geometry like the TW Hya disk. The data provided here offer the most stringent limits to date on the polarized millimeter-wavelength emission from disks around young stars.Comment: 15 pages, 6 figures, accepted for publication in Ap

A Minimal Model of Metabolism Based Chemotaxis

Since the pioneering work by Julius Adler in the 1960's, bacterial chemotaxis has been predominantly studied as metabolism-independent. All available simulation models of bacterial chemotaxis endorse this assumption. Recent studies have shown, however, that many metabolism-dependent chemotactic patterns occur in bacteria. We hereby present the simplest artificial protocell model capable of performing metabolism-based chemotaxis. The model serves as a proof of concept to show how even the simplest metabolism can sustain chemotactic patterns of varying sophistication. It also reproduces a set of phenomena that have recently attracted attention on bacterial chemotaxis and provides insights about alternative mechanisms that could instantiate them. We conclude that relaxing the metabolism-independent assumption provides important theoretical advances, forces us to rethink some established pre-conceptions and may help us better understand unexplored and poorly understood aspects of bacterial chemotaxis

Virtual reality surgical simulation as a tuition aid for understanding surgical temporal bone anatomy: trial on 15 ear, nose, and throat registrars

peer reviewe

Quality of life and anthropometric assessment of teachers working at a private school system

Objetivo: Avaliar a associação entre a qualidade de vida (QV) e parâmetros antropométricos e de docência, de professores de uma rede privada de ensino de São Paulo. Métodos: Realizou-se estudo transversal descritivo com 107 professores, utilizando-se dois questionários autoaplicáveis, abordando aspectos sociodemográficos, variáveis da docência e de QV (World Health Organization Quality on Life Bref - WHOQOL-bref). Após o preenchimento, os sujeitos foram submetidos às medidas de peso, estatura, índice de massa corporal (IMC) e circunferência da cintura (CC). Resultados: Os professores tinham idade média de 38,2 ± 8,6 anos, 78,5% do sexo feminino, 78,5% casados, 74,8% pertencente à classe B. Todos os professores possuíam ensino superior completo, 64,5% até 10 anos de atuação, 88,8% trabalhavam mais de 20h/semana, 44,9% atuavam em dois turnos ou mais, 55,1% encontravam-se com excesso de peso, 71,1% em risco para doença metabólica e 84,1% consideravam sua QV boa ou muito boa. Nenhuma das variáveis antropométricas, de tempo de docência, de carga horária e da classe econômica, correlacionarem-se significantemente à QV. Correlações fracas, mas significantes, foram observadas entre o tempo de docência e IMC e CC (r=0,26 e r=-0,22, p&lt;0,05). Contudo, verificou-se significante associação (p&lt;0,05) da QV (&lt;71pontos: 35,6±7,9anos vs. ³71pontos: 40,0±9,0anos) com a idade, do IMC (&lt;25kg/m2: 59,0±7,4kg vs. ³25kg/m2: 80,3±15,0kg) com o peso e a circunferência da cintura (&lt;25kg/m2: 80,6±6,9cm vs. ³25kg/m2: 95,9±10,5cm). Conclusão: Embora a percepção da QV seja satisfatória, ela não se relacionou às variáveis antropométricas, sociodemográficas e de docência. Porém, o tempo de docência relacionou-se significantemente ao IMC e à CC.Objective: To evaluate the association between quality of life (QoL) and anthropometric and teaching parameters of teachers from a private school system in São Paulo. Methods: A descriptive cross-sectional study was conducted with 107 teachers, using two self-administered questionnaires, addressing sociodemographic aspects, teaching and QoL variables (WHOQOL-bref). After completion, the subjects were submitted to weight, height, body mass index (BMI) and waist circumference (WC) measurements. Results: The teachers had an average age of 38.2±8.6 years, and 78.5% were female, 78.5% were married, 74.8% belonged to class B. All teachers had completed higher education, 64.5 % had up to 10 years of work, 88.8% worked more than 20h/week, 44.9% worked two shifts or more, 55.1% were overweight, 71.1% at risk of metabolic disease and 84.1% considered their QoL good or very good. None of the anthropometric, teaching time, workload and economic class variables significantly correlated with QoL. Weak but significant correlations were observed between teaching time and BMI and WC (r = 0.26 and r = -0.22, p &lt;0.05). However, there was a significant association (p &lt;0.05) of QoL (&lt;71 points: 35.6±7.9 years vs. 71 points: 40.0±9.0 years) with age, BMI (&lt;25kg / m2: 59.0±7.4kg vs. ³25kg/m2: 80,3±15.0kg) with weight and waist circumference (&lt;25kg / m2: 80,6±6,9cm vs. ³25kg/m2: 95,9±10.5cm). Conclusion: Although the perception of QOL is satisfactory, it was not related to anthropometric, sociodemographic and teaching variables. However, teaching time was significantly related to BMI and WC

SDSS-IV MaNGA:the spatially resolved stellar initial mass function in ∼ 400 early-type galaxies

MaNGA provides the opportunity to make precise spatially resolved measurements of the IMF slope in galaxies owing to its unique combination of spatial resolution, wavelength coverage and sample size. We derive radial gradients in age, element abundances and IMF slope analysing optical and near-infrared absorption features from stacked spectra out to the half-light radius of 366 early-type galaxies with masses $9.9 - 10.8\;\log M/M_{\odot}$. We find flat gradients in age and [$\alpha$/Fe] ratio, as well as negative gradients in metallicity, consistent with the literature. We further derive significant negative gradients in the [Na/Fe] ratio with galaxy centres being well enhanced in Na abundance by up to 0.5 dex. Finally, we find a gradient in IMF slope with a bottom-heavy IMF in the centre (typical mass excess factor of 1.5) and a Milky Way-type IMF at the half-light radius. This pattern is mass-dependent with the lowest mass galaxies in our sample featuring only a shallow gradient around a Milky Way IMF. Our results imply the local IMF-$\sigma$ relation within galaxies to be even steeper than the global relation and hint towards the local metallicity being the dominating factor behind the IMF variations. We also employ different stellar population models in our analysis and show that a radial IMF gradient is found independently of the stellar population model used. A similar analysis of the Wing-Ford band provides inconsistent results and further evidence of the difficulty in measuring and modelling this particular feature.Comment: 28 pages, 24 figures, 9 tables. MNRAS in pres

SDSS-IV MaNGA: The Spatially Resolved Stellar Initial Mass Function in ~400 Early-Type Galaxies

Mapping Nearby Galaxies at Apache Point Observatory provides the opportunity to make precise spatially resolved measurements of the IMF slope in galaxies owing to its unique combination of spatial resolution, wavelength coverage, and sample size. We derive radial gradients in age, element abundances, and IMF slope analysing optical and near-infrared absorption features from stacked spectra out to the half-light radius of 366 early-type galaxies with masses 9.9–10.8 log M/M⊙. We find flat gradients in age and [α/Fe] ratio, as well as negative gradients in metallicity, consistent with the literature. We further derive significant negative gradients in the [Na/Fe] ratio with galaxy centres being well enhanced in Na abundance by up to 0.5 dex. Finally, we find a gradient in IMF slope with a bottom-heavy IMF in the centre (typical mass excess factor of 1.5) and a Milky Way-type IMF at the half-light radius. This pattern is mass dependent with the lowest mass galaxies in our sample featuring only a shallow gradient around a Milky Way IMF. Our results imply the local IMF–σ relation within galaxies to be even steeper than the global relation and hint towards the local metallicity being the dominating factor behind the IMF variations. We also employ different stellar population models in our analysis and show that a radial IMF gradient is found independently of the stellar population model used. A similar analysis of the Wing-Ford band provides inconsistent results and further evidence of the difficulty in measuring and modelling this particular feature

Qualidade de vida de enfermeiros e sua relação com a alimentação e o cortisol

Objetivo: Avaliar a qualidade de vida de enfermeiros de um serviço público em Sinop-MT Metodologia: Estudo transversal com 33 enfermeiros. As variáveis sociodemográficas, de qualidade de vida, do consumo alimentar e antropométricas foram obtidas através de quatro questionários autoaplicáveis. O cortisol plasmático foi coletado e avaliado por laboratório privado da região. As análises foram realizadas pelo Statistical Package for the Social Sciences e Graph Pad Prism, com nível de significância de 5%. Resultados e Conclusões: Houve predomínio de enfermeiros casados, do sexo feminino e de classe econômica A ou B. O escore de alimentação correlacionou-se positiva e significantemente com o dominio psicológico e nível de cortisol. O cortisol médio foi de 11,6 ug/dle correlacionou-se positiva e significantemente com os domínios físico, ambiente e ao escore geral de qualidade de vida. O peso corporal correlacionou-se inversa e significantemente com os domínios físico, psicológico, ambiente, o escore geral de qualidade de vida e à classe socioeconômica. Os enfermeiros possuem alto nível socioeconômico e baixa prevalência de excesso de peso. A percepção da qualidade de vida geral e nos seus quatro domínios pelos enfermeiros estudados foi regular e boa. O consumo alimentar e outros hábitos de vida apresentaram-se razoáveis, requerendo atenção por parte destes profissionais.Objetivo: Evaluar la calidad de vida de los enfermeros de un servicio público en Sinop-MT Metodología: Estudio transversal con 33 enfermeros. Las variables sociodemográficas, de calidad de vida, del consumo alimentario y antropométrico se obtuvieron a través de cuatro cuestionarios autoaplicables. El cortisol plasmático fue recogido y evaluado por laboratorio privado de la región. Los análisis fueron realizados por el Statistical Package for the Social Sciences y GraphPad Prism, con un nivel de significancia del 5%. Resultados y Conclusión: Hubo predominio de enfermeros casados, del sexo femenino y de clase económica A o B. La puntuación de alimentación se correlacionó positiva y significante con el dominio psicológico y nivel de cortisol. El cortisol medio fue de 11,6 ug / dl y se correlacionó positivamente y significante con los dominios físico, ambiente y el puntaje general de calidad de vida. El peso corporal se correlacionó inversamente y significante con los dominios físico, psicológico, ambiente, el puntaje general de calidad de vida y la clase socioeconómica. Los enfermeros poseen alto nivel socioeconómico y baja prevalencia de exceso de peso. La percepción de la calidad de vida general y en sus cuatro dominios por los enfermeros estudiados fue regular y buena. El consumo alimentario y otros hábitos de vida se presentaron razonables, requiriendo atención por parte de estos profesionales.Objective: To evaluate the quality of life of nurses in a public service in Sinop-MT. Methodology: A cross-sectional study with 33 nurses. The sociodemographic, quality of life, food consumption and anthropometric variables were obtained through four self-administered questionnaires. Plasma cortisol was collected and evaluated by a private laboratory in the region. The analyzes were performed by the Statistical Package for the Social Sciences and GraphPad Prism, with significance level of 5%. Results and Conclusion: There was a predominance of married nurses, female and of economic class A or B. The feeding score correlated positively and significantly with the psychological domain and level of cortisol. Mean cortisol was 11.6 ug / dl and correlated positively and significantly with the physical, environmental and overall quality of life scores. Body weight correlated inversely and significantly with the physical, psychological, environmental, general quality of life and socioeconomic class domains. Nurses have high socioeconomic level and low prevalence of overweight. The perception of general quality of life and in its four domains by the nurses studied was regular and good. Food consumption and other lifestyle habits were reasonable, requiring attention from these professionals