Dimensional reduction of the CPT-even electromagnetic sector of the Standard Model Extension

The CPT-even abelian gauge sector of the Standard Model Extension is represented by the Maxwell term supplemented by $(K_{F})_{\mu\nu\rho\sigma}F^{\mu\nu}F^{\rho\sigma}$, where the Lorentz-violating background tensor, $(K_{F})_{\mu\nu\rho\sigma}$, possesses the symmetries of the Riemann tensor. In the present work, we examine the planar version of this theory, obtained by means of a typical dimensional reduction procedure to $(1+2)$ dimensions. The resulting planar electrodynamics is composed of a gauge sector containing six Lorentz-violating coefficients, a scalar field endowed with a noncanonical kinetic term, and a coupling term that links the scalar and gauge sectors. The dispersion relation is exactly determined, revealing that the six parameters related to the pure electromagnetic sector do not yield birefringence at any order. In this model, the birefringence may appear only as a second order effect associated with the coupling tensor linking the gauge and scalar sectors.The equations of motion are written and solved in the stationary regime. The Lorentz-violating parameters do not alter the asymptotic behavior of the fields but induce an angular dependence not observed in the Maxwell planar theory.Comment: 13 pages, revtex style, no figures, to appear in Physical Review D(2011

Taxonomía de esponjas Poecillastra (Astrophorida: Pachastrellidae), con la descripción de tres nuevas especies batiales del Pacífico suroriental

Three new species of Poecillastra are described here from bathyal waters off central Chile. P. antonbruunae n. sp. is diagnosed by its two categories of oxeas, the smaller one only up to 621 μm in length, and calthrops as the sole triaene category; P. sinetridens n. sp. by the possession of oxeas larger than 3000 μm long, microxeas which can be over 300 μm long, and absence of triaenes; and P. maremontana n. sp. by its three categories of oxeas, three categories of streptasters (one of spirasters and two of plesiasters), one category of calthrops and centrotylote microxeas. Comments upon other Poecillastra and an identification key for Pacific species of the genus are given. Evolutionary hypotheses are discussed for the genus given the distribution of spicule morphotypes, as well as the recurrent phenomenon of spicule loss in Astrophorida. Five species of Pachastrella are transferred here to Poecillastra on the basis of their possession of microxeas instead of microrhabds, viz. P. cribrum Lebwohl, 1914; P. dilifera de Laubenfels, 1934 [sensu Dickinson (1945)]; P. fusca Lebwohl, 1914; P. incrustata Bergquist, 1968; and P. scrobiculosa Lebwohl, 1914. We recognize 28 species of Poecillastra, 19 of them occurring in the Pacific Ocean.El presente trabajo describe tres nuevas especies de Porifera del género Poecillastra, de aguas profundas de la región central de Chile. P. antonbruunae n. sp. presenta dos categorías de oxeas, la más pequeña solo hasta 621 μm de longitud y calthrops como la categoría única de trienios; P. sinetridens n. sp. posee oxeas de tamaño superior a 3000 μm de longitud, sus microxeas alcanzan un tamaño superior a 300 μm de longitud y los trienios están ausentes. P. maremontana n. sp. posee tres categorías de oxeas y tres de streptasters (una de spirasters y dos de plesiasters). Posee además una sola categoría de calthrops y microxeas centrotylotadas. En el presente trabajo se incluyen comentarios acerca de otras especies de Poecillastra, así como una clave de identificación del género para las especies del Pacífico. Se discuten también hipótesis evolutivas del género, basadas sobre la distribución de sus diferentes morfotipos espiculares, así como el fenómeno recurrente de la pérdida de espículas en el orden Astrophorida. Cinco especies del género Pachastrella fueron transferidas para Poecillastra en consecuencia de poseer micróxeas en vez de microrabdos, viz. P. cribrum Lebwohl, 1914; P. dilifera de Laubenfels de 1934 [sensu Dickinson (1945)]; P. fusca Lebwohl, 1914; P. incrustata Bergquist, 1968; y P. scrobiculosa Lebwohl de 1914. Actualmente consideramos válidas 28 especies de Poecillastra, 19 de ellas ocurren en el Océano Pacífico

Otimização da produção de biodiesel a partir de óleo de coco babaçu com aquecimento por microondas

As reações sob aquecimento por microondas geralmente apresentam significativa redução no tempo de reação e elevados rendimentos. Portanto, o objetivo desse trabalho foi adaptar um forno de microondas doméstico de forma adequada e segura para realização de reações de transesterificação, e otimizar o processo de produção de biodiesel por microondas usando óleo de coco babaçu como matéria prima. Para este fim, foi usado um planejamento composto central no qual se variou o tempo de irradiação, concentração de KOH e razão óleo:metanol. Análises estatísticas foram feitas para avaliarem a significância do modelo usado. As condições experimentais ótimas foram: razão óleo:metanol, 8,59, concentração de KOH, 2,19%, tempo de irradiação, 70 segundos, dando rendimento de aproximadamente 100%.Reactions under microwave heating present reduced reaction times and larger yields. Therefore, this work is aimed at adapting a domestic microwave oven and optimizing the transesterification reaction used in biodiesel production with microwave heating, using babaçu coconut oil as raw material. It was used a central composite design for varying irradiation time, KOH concentration, and oil:methanol ratio. Statistical analyses were performed in order to assess the significance of the model used. The optimized experimental conditions were: oil:methanol ratio, 8.59; KOH concentration, 2.19 %; and irradiation time, 70 seconds, giving an yield of approximately 100% regarding esters formation.FAPEM

Modeling of FiO2 delivered by self-inflating ventilation device: Modelagem de FiO2 entregue por bolsa auto inflável

During the COVID-19 pandemic, professionals in the medical field have been using bag resuscitators, also called bag valve masks, to provide respiratory support for patients for long periods. A relevant issue arising because of such use is the little information regarding the FiO2 delivered by these devices, leading to toxic effects of O2 and its waste. This paper presents a model that relates volume, respiratory frequency, and flow in an O2 line with the FiO2 delivered by bag resuscitators. The model was obtained based on a formal procedure and data from a 1500 ml Hsiner bag resuscitator collected in the literature, both presented in this paper. Then, we compared through Bland-Altman analysis the FiO2 values estimated by our model with the ones from data considering different bag resuscitators to evaluate the amplitude of the errors it can generate. The average error for Hsiner and Laerdal bag resuscitators was less than 0.035 (or 3.5%) and less than 0.063 (or 6.3%) for Ambu devices. The maximum error found for Ambu bag resuscitators was high. The obtained model presented satisfactory errors, compatible with the uncertainty levels associated with FiO2 measuring instruments and blenders, meaning the model can be used to estimate the delivered FiO2 accurately. Additionally, the procedure presented in this paper can be used to obtain specific models for bag resuscitators of other companies, equipping professionals with tools that can accurately estimate FiO2

The perspective of science and religion in high school biology teachers in Argentina, Brazil and Uruguay: a comparative study

7th World Conference on Educational Sciences, (WCES-2015), 05-07 February 2015, Athens, Greece.The relationship between science and religion has been marked by historically constructed movements of proximity and conflict. We have investigated how high school biology teachers from three countries with different relationships between State and religion, Argentina, Brazil and Uruguay, conceive the science-religion relationship. Uruguay has consolidated secularism, Argentina has an official religion and Brazil calls itself secular, but its secularism is only relative. Fifty high school biology teachers from each country answered the European BIOHEAD-CITIZEN data collection questionnaire, which investigates teachers' conceptions of biological evolution, health, sexuality, and other topics. The question used was "Should science and religion be separate?" Conflict, independence, dialogue and integration categories were considered in the analysis and the results were submitted to parametric testing. Most Uruguayan high school biology teachers tended to agree with the investigated question, with a lower ratio in Brazil, followed by Argentina. Uruguayan teachers tended to be more assertive in their agreement. The main category was partially confirmed as teachers from Uruguay, the country with a greater secular tradition, tended to agree with the separation between science and religion. In Brazil and Argentina, the category was not confirmed. In Brazil, a self-proclaimed secular country, high school biology teachers were more opposed to the separation between science and religion, while in Argentina, a country with an official religion, they supported the possibility of dialogue and integration between them. We concluded that the respondents felt that science and religion should be separate, but trends varied according to the historical and cultural religiosity features of the selected countries, with a partial influence of secularism on the responses.CIEC – Research Centre on Child Studies, IE, UMinho (FCT R&D unit 317), Portuga

Sugarcane straw polyphenols as potential food and nutraceutical ingredient

The sugarcane processing industry generates a large amount of straw, which has a negative environmental impact, and high costs are associated with their elimination, wasting their potential bioactive value attributed to their richness in polyphenols. In this study, an ethanolic extract produced from sugarcane straw was screened for its phenolic compounds content, and the potential use of this extract in the development of a food ingredient was further evaluated. Fifty different secondary metabolites belonging to the hydroxybenzoic acids, hydroxycinnamic acids, and flavonoids were identified by liquid chromatography–electrospray ionization–ultrahigh-resolution—quadrupole time of flight–mass spectrometry (LC-ESI-UHR-QqTOF-MS). The predominant phenolic compounds found were 4-hydroxybenzaldehyde, chlorogenic acid, and 5-O-feruloylquinic acid. The obtained extracts showed strong potential as food preservatives by exhibiting (a) antioxidant activity using both 2.2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt radical cation (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) methods; and (b) antimicrobial capacity, with a minimum inhibitory concentration of 50 mg/mL for Staphylococcus aureus, 74% inhibition for Bacillus cereus, and 44% for Salmonella enterica; and (c) the capacity to inhibit a food browning enzyme, tyrosinase (28–73% for 1–8 mg/ mL). Moreover, the extracts showed antidiabetic potential by inhibiting the enzymes α-glucosidase (15–38% for 1.25–5.00 mg/mL) and dipeptidyl peptidase-IV (DPP-IV) (62–114% for 0.31–5.00 mg/mL). The extract (0.625 mg/mL) also exhibited the capacity to reduce proinflammatory mediators (i.e., interleukins 6 and 8, and tumor necrosis factor alpha) when Caco-2 cells were stimulated with interleukin 1 beta. Thus, sugarcane straw extract, which is rich in phenolic compounds, showed high potential to be used in the development of food-preservative ingredients owing to its antioxidant and antimicrobial potential, and to be explored as a food supplement in diabetes prevention and as coadjuvant to reduce intestinal inflammation by reducing proinflammatory mediators.info:eu-repo/semantics/publishedVersio

Central Neurogenic Respiratory Failure: A Challenging Diagnosis

Background: Central nervous system lesions are rare causes of respiratory failure. Simple observation of the breathing pattern can help localize the lesion, but the examiner needs to be aware of potential pitfalls such as metabolic or pulmonary alterations. Methods: We describe 3 cases in which central neurogenic respiratory failure occurred simultaneously with other alterations or in an unusual presentation. Results: All patients were diagnosed with central neurogenic respiratory failure and treated for it with good recovery. Conclusion: Central neurogenic respiratory failure is a challenging diagnosis and needs to be reminded in difficult-to-wean patients carrying inconclusive evidences of metabolic or pulmonary alterations