AG codes from the second generalization of the GK maximal curve

The second generalized GK maximal curves $\mathcal{GK}_{2,n}$ are maximal curves over finite fields with $q^{2n}$ elements, where $q$ is a prime power and $n \geq 3$ an odd integer, constructed by Beelen and Montanucci. In this paper we determine the structure of the Weierstrass semigroup $H(P)$ where $P$ is an arbitrary $\mathbb{F}_{q^2}$-rational point of $\mathcal{GK}_{2,n}$. We show that these points are Weierstrass points and the Frobenius dimension of $\mathcal{GK}_{2,n}$ is computed. A new proof of the fact that the first and the second generalized GK curves are not isomorphic for any $n \geq 5$ is obtained. AG codes and AG quantum codes from the curve $\mathcal{GK}_{2,n}$ are constructed; in some cases, they have better parameters with respect to those already known

Reseña: Teaching literature and language through multimodal texts, por Elena Domínguez Romero, Jelena Bobkina y Svetlana Stefanova

Reseña de Teaching literature and language through multimodal texts, por Elena Domínguez Romero, Jelena Bobkina y Svetlana Stefanov

Avaliação de alumínio trocável em solos ácidos

One of the main factors limiting agricultural production in tropical climate regions is mainly related to the presence of exchangeable aluminum (Al3+) in highly weathered acid soils. Four methods of Al3+ determination extracted with neutral 1 mol L¹ KCl solution were evaluated: three colorimetric methods (aluminon plus ascorbic acid, and eriochrome cyanine R by FIA) and the usual titrimetric method with back-titration. Surface samples from 20 soils of different Brazilian regions, with active acidity (0.01 mol L¹ CaCl2 pH) ranging from very high to medium (3.82 to 5.52), were used. The variance analysis revealed significant interaction among Al3+ determination methods and soil. Mean methods comparisons within each soil (Tukey, P ; 10 mmol c dm³. Among colorimetric methods, in operational terms, the eriochrome with FIA method presented analytical performance up to 50 samples per hour, easiness and sensibility for routine Al analysis in soil samples. However, due to the specificity, the titration/back-titration method should be used, despite the moroseness, when the Al3+ ions are the objective.Um dos principais fatores que afetam a produção agrícola em regiões de clima tropical, é a presença de alumínio trocável (Al3+) em solos ácidos altamente intemperizados. Foram avaliados quatro métodos de determinação de alumínio trocável em solução neutra de KCl 1 mol L¹: três métodos colorimétricos (aluminon, aluminon + ácido ascórbico e eriocromo cianina R por FIA) e o método titulométrico usual com retrotitulação ácida. Para obtenção dos extratos de KCl, foram usadas amostras superficiais de 20 solos de diferentes regiões brasileiras, com acidez ativa (pH em CaCl2 0,01 mol L¹) variando de muito alta a média (3,82 a 5,52). A análise de variância revelou interação significativa entre os métodos de determinação e amostras de solos. O teste de médias (Tukey, P ; 10 mmol c dm³. Dentre os métodos colorimétricos, o reagente eriocromo cianina R, em sistema FIA, mostrou-se operacionalmente confiável e eficiente para a análise de Al, de amostras de solos, em rotina, com freqüência analítica de 50 determinações por hora. Todavia, devido à especificidade, o método titulométrico com retrotitulação deve ser usado, não obstante a morosidade, quando o objetivo é a determinação do íon Al3+

Relações entre acidez e propriedades químicas de solos brasileiros

Nos solos de regiões de clima tropical, a elevada acidez e a presença de alumínio trocável (Al3+), aliadas à baixa fertilidade, são os principais fatores a restringir a produção agrícola. Investigaram-se os componentes da acidez, com ênfase ao alumínio, e suas relações com as propriedades químicas de 26 solos de regiões brasileiras. O pH correlacionou positivamente com os valores de P, Ca, Mg, K, SB, CTC e V%, e negativamente com a saturação de Al. O Al3+ foi o cátion trocável predominante em 32 % dos solos com pH inferior a 5,6. O H+ titulável em KCl representa formas hydroxi-Al(OH)x de baixa estabilidade e o Al obtido pelo extrator de Wolf-Morgan corresponde ao Al trocável + não-trocável. As formas Al3+ e hydroxi-Al de baixa estabilidade diminuíram rapidamente com o pH até 5,5. O Al não-trocável aumentou até pH 4,5, diminuiu a seguir até pH 5,5 e aumentou lentamente com o pH de 7,0 a 7,5.In soils of tropical climate regions the high acidity and the presence of exchangeable aluminum (Al3+), associated to low fertility, are the main restrainting factors for agricultural production. A laboratory experiment was conducted using 26 soils of different Brazilian regions, to investigate soil acidity components, giving emphasis to Al and their relations with chemical properties. The pH correlated positively with P, Ca, Mg, K, BS, CEC and V% values, and negatively with Al saturation. The Al3+ was the predominant exchangeable cation in 32% of the soils with pH below 5.6. The KCl titratable H+ represents the hydroxi-Al(OH)x complex with low stability and the Wolf-Morgan extracted Al corresponds to the exchangeable + non-exchangeable Al species. The Al3+ and low stability hydroxi-Al decreased quickly with increasing pH up to 5.5. The non-exchangeable Al increased up to pH 4.5, then decreased to pH 5.5 and had a small increment from 7.0 to 7.5

An approach to normal polynomials through symmetrization and symmetric reduction

An irreducible polynomial $f\in\Bbb F_q[X]$ of degree $n$ is {\em normal} over $\Bbb F_q$ if and only if its roots $r, r^q,\dots,r^{q^{n-1}}$ satisfy the condition $\Delta_n(r, r^q,\dots,r^{q^{n-1}})\ne 0$, where $\Delta_n(X_0,\dots,X_{n-1})$ is the $n\times n$ circulant determinant. By finding a suitable {\em symmetrization} of $\Delta_n$ (A multiple of $\Delta_n$ which is symmetric in $X_0,\dots,X_{n-1}$), we obtain a condition on the coefficients of $f$ that is sufficient for $f$ to be normal. This approach works well for $n\le 5$ but encounters computational difficulties when $n\ge 6$. In the present paper, we consider irreducible polynomials of the form $f=X^n+X^{n-1}+a\in\Bbb F_q[X]$. For $n=6$ and $7$, by an indirect method, we are able to find simple conditions on $a$ that are sufficient for $f$ to be normal. In a more general context, we also explore the normal polynomials of a finite Galois extension through the irreducible characters of the Galois group.Comment: 28 page

La lectura literaria de los alumnos en el aula de Español Lengua Extranjera (ELE): análisis de las respuestas lectoras

Trabajo Fin de Máster (Modalidad B): Es un trabajo de investigación realizado durante el Prácticum II y III con la finalidad de analizar las respuestas lectoras del alumnado de ELE. El Proyecto quiere comprobar que la lectura de textos literarios contribuye al aprendizaje de la lengua extranjera y al desarrollo de habilidades de comprensión e interpretación de un texto

Biological Hydrogen Production by Dark Fermentation in a Stirred Tank Reactor and Its Correlation with the pH Time Evolution

Dark fermentation is a hydrogen generating process carried out by anaerobic spore-forming bacteria that metabolize carbon sources producing gas and short-chain acids. The process can be controlled, and the hydrogen harvested if bacteria are grown in a reactor with favorable conditions. In this work, bacteria selected from natural sources were grown with a defined culture media, while pH was monitored, with the aim of relating the amount of generated hydrogen to the increase in hydron ion concentration. Therefore, a model based on the acid-base species mass balance is proposed and solved to estimate the lag phase time and measure the hydrogen production efficiency and kinetics. Hydrogen production in a stirred batch reactor was performed for 150–200 h, at given operating conditions using a previously defined growth media, to validate the model. Using the proposed model, the cumulated moles of produced hydrogen correlate well with those predicted from the pH curve. Hence, the modified Gompertz model parameters, largely used for describing the hydrogen generation kinetics by dark fermentation, were estimated from the pH curve and from the experimentally measured generated hydrogen. Satisfactory agreement was found, thus, validating the method.Fil: Martinez, Veronica Laura. Ministerio de Defensa. Instituto de Investigaciones Científicas y Técnicas para la Defensa; ArgentinaFil: Salierno, Gabriel Leonardo. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias. Instituto de Tecnología de Alimentos y Procesos Quimicos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Tecnología de Alimentos y Procesos Quimicos.; ArgentinaFil: García, Rodrigo Enrique. Ministerio de Defensa. Armada Argentina. Dirección Gral. de Investigación y Desarrollo de la Ara; ArgentinaFil: Lavorante, Maria Jose. Ministerio de Defensa. Instituto de Investigaciones Científicas y Técnicas para la Defensa; ArgentinaFil: Galvagno, Miguel Angel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Micología y Botánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Micología y Botánica; ArgentinaFil: Cassanello Fernandez, Miryam Celeste. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias. Instituto de Tecnología de Alimentos y Procesos Quimicos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Tecnología de Alimentos y Procesos Quimicos.; Argentin

Argentine Navy Icebreaker Ship “Almirante Irizar” Sludge Microbial Composition Analysis for Biohydrogen Production

Sludge from the wastewater treatment plant of the Argentinean Navy icebreaker ship “Almirante Irizar” was used as inoculum for biohydrogen production. The bacterial community was monitored throughout the fermentation, by sequencing 16S rRNA amplicons, to establish the microbial dynamics of the bioreactor over time. The established operating procedure assured a hydrogen content, along the process, in the range of 59.2–70.0%. The predominant species found were Clostridium sensu stricto and Sporolactobacillus sp. Clostridium showed higher values in the beginning of the fermentation with more than 90% of relative abundance. Conversely, Sporolactobacillus reached values close to 20% at its end. Additional topics discussed are the role of lactic acid bacteria in fermentative biohydrogen production systems and a series of in-process parameters that would allow control of this population. The results obtained allow supporting the use of this type of sludge as a source of hydrogen-producing bacteria.Fil: García, Rodrigo Enrique. Ministerio de Defensa. Instituto de Investigaciones Científicas y Técnicas para la Defensa; ArgentinaFil: Pin Viso, Natalia Daniela. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación En Ciencias Veterinarias y Agronómicas. Instituto de Agrobiotecnología y Biología Molecular. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Agrobiotecnología y Biología Molecular; ArgentinaFil: Gerosa, Fernando Ariel. Ministerio de Defensa. Instituto de Investigaciones Científicas y Técnicas para la Defensa; ArgentinaFil: Nishinakamasu, Verónica Cecilia. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación En Ciencias Veterinarias y Agronómicas. Instituto de Agrobiotecnología y Biología Molecular. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Agrobiotecnología y Biología Molecular; ArgentinaFil: Puebla, Andrea Fabiana. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación En Ciencias Veterinarias y Agronómicas. Instituto de Agrobiotecnología y Biología Molecular. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Agrobiotecnología y Biología Molecular; ArgentinaFil: Farber, Marisa Diana. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación En Ciencias Veterinarias y Agronómicas. Instituto de Agrobiotecnología y Biología Molecular. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Agrobiotecnología y Biología Molecular; ArgentinaFil: Lavorante, Maria Jose. Ministerio de Defensa. Instituto de Investigaciones Científicas y Técnicas para la Defensa; Argentin

Mejoras en el sistema autónomo de generación de energía instalado en la Base Esperanza de la Antártida

Un sistema autónomo alimentado con una batería a combustible hidrógeno con tecnología propia estuvo funcionando en la Base Esperanza de la Antártida desde enero de 2007 hasta mayo de 2008, cuando volvió al continente para su reciclado. Describimos aquí la detección del origen de fallas, las mejoras introducidas y los resultados obtenidos en su funcionamiento nuevamente en la Base Esperanza a partir de octubre de 2008 hasta la fecha.An autonomous system powered by a hydrogen fuel cell stack was running at Base Esperanza (Antarctica) since January 2007 until May 2008, when it returned to the continent for recycling. It is described in this work the evidence of detection of failures and the improvements introduced to our own tecnology. Results obtained for de recycled stack once again at Base Esperanza are also shown (october 2008 to date).Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES