bluuebunny/crossref_metadata_2025_split huggingface dataset:
Manipulating crop row orientation and crop density to suppress Lolium rigidum
Authors: Borger C P D , Hashem A , Powles S B 
Published: September 2015

SummaryLight is an important resource that crops and weeds compete for and so increased light interception by the crop can be used as a method of weed suppression in cereal crops. This research investigated the impact of altered availability of photosynthetically active radiation (PAR) (from crop row orientation or seeding rate) on the growth and fecundity of Lolium rigidum. Wheat and barley crops were sown in an east–west (EW) or north–south (NS) direction, at a high or low seeding rate, in three field trials in 2010 and 2011 (at Merredin, Wongan Hills and Katanning, Western Australia). The average PAR available to L. rigidum in the inter‐row space of EW crops compared with NS crops was 78% to 91% at crop tillering, 39% to 56% at stem elongation, 28% to 53% at boot/anthesis and 41% to 59% at grain fill. Reduced PAR in the EW crop rows resulted in reduced L. rigidum fecundity in five of the six trials (average of 2968 and 5705 L. rigidum seeds m−2 in the EW and NS crops). Availability of PAR was not influenced by seeding rate, but the high seeding rate reduced fecundity in three of the six trials (average of 3354 and 5092 seeds m−2 in the crops with high and low seeding rate). Increased competitive ability of crops (through increased interception of PAR or increased crop density) was highly effective in reducing L. rigidum fecundity and is an environmentally friendly and low cost method of weed suppression.
Pathogen Loading From Canada Geese Faeces in Freshwater: Potential Risks to Human Health Through Recreational Water Exposure
Authors: Gorham T. J. , Lee J. 
Published: September 2015

SummaryCanada geese (Branta canadensis) faeces have been shown to contain pathogenic protozoa and bacteria in numerous studies over the past 15 years. Further, increases in both the Canada geese populations and their ideal habitat requirements in the United States (US) translate to a greater presence of these human pathogens in public areas, such as recreational freshwater beaches. Combining these factors, the potential health risk posed by Canada geese faeces at freshwater beaches presents an emerging public health issue that warrants further study. Here, literature concerning human pathogens in Canada geese faeces is reviewed and the potential impacts these pathogens may have on human health are discussed. Pathogens of potential concern include Campylobacter jejuni, Salmonella Typhimurium, Listeria monocytogenes, Helicobacter canadensis, Arcobacter spp., Enterohemorragic Escherichia coli pathogenic strains, Chlamydia psitacci, Cryptosporidium parvum and Giardia lamblia. Scenarios presenting potential exposure to pathogens eluted from faeces include bathers swimming in lakes, children playing with wet and dry sand impacted by geese droppings and other common recreational activities associated with public beaches. Recent recreational water‐associated disease outbreaks in the US support the plausibility for some of these pathogens, including Cryptosporidium spp. and C. jejuni, to cause human illness in this setting. In view of these findings and the uncertainties associated with the real health risk posed by Canada geese faecal pathogens to users of freshwater lakes, it is recommended that beach managers use microbial source tracking and conduct a quantitative microbial risk assessment to analyse the local impact of Canada geese on microbial water quality during their decision‐making process in beach and watershed management.
Reducción del riesgo sísmico para el patrimonio arquitectónico. Una comparación entre experiencias de Colombia y Japón
Authors: Niglio Olimpia , Valencia Mina William 
Published: September 2015

El riesgo sísmico es una problemática en muchos países, sobre todo de América Latina, del Medio Oriente y del extremo Oriente, y en particular Japón. A partir del análisis de la sismicidad y el patrimonio construido en Japón y Colombia, este artículo presenta el primer resultado de una investigación comparativa entre los dos países, las diferentes<br />metodologías de intervención y de gestión para la protección el patrimonio arquitectónico, lo cual es importante para reducir su vulnerabilidad. Este documento también presenta algunas reflexiones sobre las normas jurídicas y técnicas tanto en Japón como en Colombia para la salvaguardia del patrimonio cultural construido en zonas con un<br />nivel de amenaza sísmica importante y sus estrategias de prevención.
Medición de activos no financieros. Un análisis de los elementos que intervienen en la decisión de la gerencia al optar por el modelo del valor razonable
Authors: Castellanos Sánchez Heiberg Andrés 
Published: September 2015

Las Normas Internacionales de Información Financiera (2014) prevén un tratamiento alternativo para la medición posterior de activos no financieros. A tal efecto, al momento de definir sus políticas contables, la gerencia de la entidad debe seleccionar entre el modelo del costo histórico y el modelo del valor razonable. Este trabajo investigativo se centra en examinar los elementos que intervienen en la decisión de la gerencia al optar por la aplicación del valor razonable en la medición de activos no financieros. El estudio se enmarca en un enfoque cualitativo, circunscrito a la modalidad documental. En esta revisión, destaca la identificación de elementos relacionados con relevancia de la información financiera, restricción del costo, medidas de rentabilidad, medidas de endeudamiento, medidas de costo de oportunidad y perfil de la gestión empresarial.
Adiós a Gabriel García Márquez
Authors: Perilli Carmen 
Published: September 2015

Extracto del ensayo: "Mi historia personal, como la de muchos otros de mi generación, está unida a la lectura de Cien años de soledad. La escena de lectura de la primera edi- ción del barquito, en una siesta interminable en un pueblo de provincia, donde siempre es lunes, me volcó, de modo definitivo, hacia la literatura. A lo largo de estos años las innumerables incursiones en sus páginas dieron lugar a mi trabajo de tesis. Hoy continúan alimentando mi escritura y mis seminarios donde vuelvo una y otra vez sobre el mundo del colombiano. La muerte de Gabriel García Márquez me desafió a recorrer nuevamente el viejo libro. Y volví a ser atrapada en ese mundo sorprendente que, a cada instante, asalta con invenciones de la imaginación y que tiene la virtud de decir la realidad de una manera luminosa. Cada lectura, una aventura incomparable, en un espacio desconocido y miste- rioso de papel".
Obtención de biodiesel a partir de aceite usado de cocina por trans-esterificación
Authors: Bocanegra Jenny Paola , Malagón Dionisio Humberto , López Luisa Fernanda 
Published: September 2015

<p>La evaluación de diferentes aceites vegetales para la obtención de biocombustibles se ha convertido en una estrategia global en la producción de biodiesel, con miras a la reducción de costos de producción, aumentar el rendimiento de la reacción, evitar el uso de materias primas consideradas como alimentos y disminuir la contaminación ambiental. En el presente trabajo se evaluó la obtención de biodiesel a partir de aceite usado de cocina, por medio de catálisis con hidróxido de sodio y potasio. Se evaluaron tres relaciones molares de metanol:aceite, 6:1, 9:1 y 12:1, dos catalizadores KOH y NaOH y dos porcentajes de catalizador 1% y 2%; se realizó un diseño factorial por duplicado. La temperatura se mantuvo en 60°C y el tiempo de reacción en 2 horas. Se determinó el contenido de metil ésteres, mono, di y triglicéridos mediante cromatografía de gases. Las mejores condiciones para NaOH y KOH como catalizadores se obtuvieron cuando el porcentaje de catalizador fue 1% y la relación molar alcohol:aceite fue 12:1. En estas condiciones se obtuvo una conversión del 64,1 %, un rendimiento de 98 % y un porcentaje de metil ésteres de 99,1% cuando el catalizador fue NaOH; con KOH la conversión fue 63,2%, el rendimiento fue 88% y el porcentaje de metil-ésteres fue 98,4%. Los resultados de este estudio muestran un alto rendimiento de la reacción usando aceite usado, por lo cual su implementación a nivel industrial dependerá de la evaluación económica.</p><p> </p>
Sistema de identificación de intención de movimiento para el control mioeléctrico de una prótesis de mano robótica
Authors: Quinayas Burgos Cesar Augusto , Gaviria López Carlos Alberto 
Published: September 2015

Este artículo presenta un sistema embebido que detecta en tiempo real la intención de movimiento para el control de un prototipo de prótesis de mano robótica. El trabajo muestra que usando características temporales de cálculo simple, es posible obtener un agrupamiento de vectores de características lo suficientemente discriminante como para que se puedan usar clasificadores de patrones muy simples. Así, en este trabajo se propone un clasificador basado en la mínima distancia al centroide de los grupos que caracterizan a los movimientos a identificar, modificando el conocido algoritmo k vecinos próximos para sacar mayor provecho de la fase de entrenamiento del clasificador en la fase de clasificación y obtener respuesta en tiempo real. Se presentan resultados de clasificación de intención de movimiento obtenidos con el sistema desarrollado usando el porcentaje de éxito como medida de efectividad, al realizar pruebas sobre tres sujetos con músculos sanos. Los resultados experimentales muestran que el sistema puede ser utilizado efectivamente para el control de ejecución de cuatro primitivas motoras de un prototipo de prótesis de mano robótica.
Effect of Aging on the Properties of Asphalt and Asphalt Mixtures
Authors: Higuera Sandoval Carlos Hernando , Camargo Amaya Xiomara Vanessa , Suárez Molano Edwin Alexander 
Published: September 2015

This article presents the results of the analysis of the effect of aging on the properties of asphalt and asphalt mixtures. The objective of this study was to compare the properties of the original asphalt and aged asphalt and the dynamic modulus of asphalt mixtures. The long-term aging was simulated by using Pressure Asphalt Vessel (PAV). Marshall and RAMCODES methodologies were used to determine the formula of work; values of dynamic modulus of designed mixtures were obtained by the indirect tensile test, using the Nottingham Asphalt Tester (NAT). The results showed an increase in the rigidity of the aged asphalt. Also, an increase of the stability and a decreased flow in the mixtures made with this type of binder was found. The dynamic modulus values of the mixtures containing aged asphalt showed an increase up to three times compared with those elaborated with original asphalt mixtures.
Ontology, Epistemology, Strategy and Method in Educational Research. A Critical Realist Approach
Authors: Scott David 
Published: September 2015

This article focuses on the development of a meta-theory for the use and application of qualitative strategies and methods. This meta-theory is sometimes referred to as critical realism, though it is important to acknowledge that there are in existence a number of rival theories that are described as critical realist. The suggestion being made here is that methods and strategies used by researchers to collect and analyse data in the world cannot be a-epistemic, but in every case are underpinned by ontological and epistemological frameworks. In particular, </span><span>the issue of causality is central to any framework that is adopted. Since researchers cannot avoid these philosophical issues then it is obligatory for them to base their methods, strategies and modus operandi on a meta-theory which is both more rational and, in addition, fully comprehensive.
Análisis comparado de las políticas públicas de defensa de México y Brasil. Retos de una nueva contrainsurgencia*
Authors: Montero Moncada Luís Alexander , Herrera Ángela , Abril Pérez Liliana 
Published: September 2015

La evolución de la doctrina de contrainsurgencia ha tenido en el escenario latinoamericano un espacio interesante para matizar las diferentes escuelas teóricas y para experimentar adecuacionesespeciales según las necesidades imperantes en la región. En ese sentido, las políticas públicas de seguridad y defensa de México y Brasil ofrecen patrones claros de retos y amenazas que desarrollannuevas formas de atacar a los Estados, así como las respuestas que se han concebido desde novedosas concepciones de contrainsurgencia.
LA CIENCIA POLÍTICA EN COLOMBIA. Análisis de los planes de estudio, sus áreas y sus énfasis
Authors: Duque Daza Javier 
Published: September 2015

El artículo analiza las características de los planesde estudio del campo de la ciencia política en Colombia. Se estudian cinco dimensiones de la enseñanza de la ciencia política en el país: 1) las intersecciones y convergencias en subcampos de la disciplina, 2) los énfasis, 3) los planes de estudio, 4) los contextos políticos y 5) la investigaciónformativa. El argumento central es que no obstante la diversidad en los nombres y contenidos de los planes de estudio, hay lugares de encuentro y convergencia en la formación, hay intersecciones que permiten hablar de un núcleo compartido por gran parte de los planes de estudio relacionado con la ciencia política y los que suelen ser considerados como los subcampos de la disciplina. Además de las intersecciones,encontramos que hay diversos grados de desarrollo y consolidación de los programas y diferencias y variedad en los énfasis formativos y en la valoración e importancia asignada a la formación investigativa.
La narrativa de las políticas públicas en la jurisprudencia de la Corte Constitucional colombiana
Authors: Cano Blandón Luisa Fernanda 
Published: September 2015

Pese a que la referencia al Derecho en la teoría de las políticas públicas es escasa, en Colombia ha crecido el interés jurídico en este tema en los últimos años. En la vía inversa, los analistas de políticas públicas han prestado mayor atenciónal Derecho –y a los derechos– más allá de asumirlo como el marco jurídico institucional de toda política. Una de las razones de esta reciente conexión es la reiterativa referencia al concepto de políticas públicas en la jurisprudenciaconstitucional colombiana. El objetivo de este escrito es reconstruir la narrativa de la Corte Constitucional alrededor de la noción de políticas públicas desde la promulgación de la Constitución de 1991 hasta el año 2013. El referente para esta tarea es el análisis narrativo de políticas públicas sustentado principalmente por Emery Roe (1994).La reconstrucción de tal narrativa se lleva a cabo en dos momentos: en primer lugar, se exploran los distintos escenarios en los cuales la Corte se refiere a las políticas públicas. En segundo lugar, se aborda el aspecto formal de su narrativa, es decir, los distintos modos cómo la Corte entiende las políticas públicas y cuál es la forma o acto jurídico a la que deben ser llevadas.
Molybdenum-Containing Nicotine Hydroxylase Genes in a Nicotine Degradation Pathway That Is a Variant of the Pyridine and Pyrrolidine Pathways
Authors: Yu Hao , Tang Hongzhi , Li Yangyang , Xu Ping 
Published: September 2015

ABSTRACT

Ochrobactrum
sp. strain SJY1 utilizes nicotine as a sole source of carbon, nitrogen, and energy via a variant of the pyridine and pyrrolidine pathways (the VPP pathway). Several strains and genes involved in the VPP pathway have recently been reported; however, the first catalyzing step for enzymatic turnover of nicotine is still unclear. In this study, a nicotine hydroxylase for the initial hydroxylation step of nicotine degradation was identified and characterized. The nicotine hydroxylase (VppA), which converts nicotine to 6-hydroxynicotine in the strain SJY1, is encoded by two open reading frames (
vppA
S
and
vppA
L
[subunits S and L, respectively]). The
vppA
genes were heterologously expressed in the non-nicotine-degrading strains
Escherichia coli
DH5α and
Pseudomonas putida
KT2440; only the
Pseudomonas
strain acquired the ability to degrade nicotine. The small subunit of VppA contained a [2Fe-2S] cluster-binding domain, and the large subunit of VppA contained a molybdenum cofactor-binding domain; however, an FAD-binding domain was not found in VppA. Resting cells cultivated in a molybdenum-deficient medium had low nicotine transformation activity, and excess molybdenum was detected in the purified VppA by inductively coupled plasma-mass spectrometry analysis. Thus, it is demonstrated that VppA is a two-component molybdenum-containing hydroxylase.
Sample Dilution and Bacterial Community Composition Influence Empirical Leucine-to-Carbon Conversion Factors in Surface Waters of the World's Oceans
Authors: Teira Eva , Hernando-Morales Víctor , Cornejo-Castillo Francisco M. , Alonso-Sáez Laura , Sarmento Hugo , Valencia-Vila Joaquín , Serrano Catalá Teresa , Hernández-Ruiz Marta , Varela Marta M. , Ferrera Isabel , Gutiérrez Morán Xosé Anxelu , Gasol Josep M. 
Published: September 2015

ABSTRACT

The transformation of leucine incorporation rates to prokaryotic carbon production rates requires the use of either theoretical or empirically determined conversion factors. Empirical leucine-to-carbon conversion factors (eCFs) vary widely across environments, and little is known about their potential controlling factors. We conducted 10 surface seawater manipulation experiments across the world's oceans, where the growth of the natural prokaryotic assemblages was promoted by filtration (i.e., removal of grazers [F treatment]) or filtration combined with dilution (i.e., also relieving resource competition [FD treatment]). The impact of sunlight exposure was also evaluated in the FD treatments, and we did not find a significant effect on the eCFs. The eCFs varied from 0.09 to 1.47 kg C mol Leu
−1
and were significantly lower in the FD than in the F samples. Also, changes in bacterial community composition during the incubations, as assessed by automated ribosomal intergenic spacer analysis (ARISA), were more pronounced in the FD than in the F treatments, compared to unmanipulated controls. Thus, we discourage the common procedure of diluting samples (in addition to filtration) for eCF determination. The eCFs in the filtered treatment were negatively correlated with the initial chlorophyll
a
concentration, picocyanobacterial abundance (mostly
Prochlorococcus
), and the percentage of heterotrophic prokaryotes with high nucleic acid content (%HNA). The latter two variables explained 80% of the eCF variability in the F treatment, supporting the view that both
Prochlorococcus
and HNA prokaryotes incorporate leucine in substantial amounts, although this results in relatively low carbon production rates in the oligotrophic ocean.
Prevalence and Distribution of Listeria monocytogenes
inlA
Alleles Prone to Phase Variation and
inlA
Alleles with Premature Stop Codon Mutations among Human, Food, Animal, and Environmental Isolates
Authors: Manuel Clyde S. , Van Stelten Anna , Wiedmann Martin , Nightingale Kendra K. , Orsi Renato H. 
Published: September 2015

ABSTRACT

In
Listeria monocytogenes
, 18 mutations leading to premature stop codons (PMSCs) in the virulence gene
inlA
have been identified to date. While most of these mutations represent nucleotide substitutions, a frameshift deletion in a 5′ seven-adenine homopolymeric tract (HT) in
inlA
has also been reported. This HT may play a role in phase variation and was first identified among
L. monocytogenes
lineage II ribotype DUP-1039C isolates. In order to better understand the distribution of different
inlA
mutations in this ribotype, a newly developed multiplex real-time PCR assay was used to screen 368 DUP-1039C isolates from human, animal, and food-associated sources for three known 5′
inlA
HT alleles: (i) wild-type (WT) (A
7
), (ii) frameshift (FS) (A
6
), and (iii) guanine interruption (A
2
GA
4
) alleles. Additionally, 228 DUP-1039C isolates were screened for all
inlA
PMSCs; data on the presence of all
inlA
PMSCs for the other 140 isolates were obtained from previous studies. The statistical analysis based on 191 epidemiologically unrelated strains showed that strains with
inlA
PMSC mutations (
n
= 41) were overrepresented among food-associated isolates, while strains encoding full-length InlA (
n
= 150) were overrepresented among isolates from farm animals and their environments. Furthermore, the A
6
allele was overrepresented and the A
7
allele was underrepresented among food isolates, while the A
6
allele was underrepresented among farm and animal isolates. Our results indicate that genetic variation in
inlA
contributes to niche adaptation within the lineage II subtype DUP-1039C.
Metabolic Adaptations of Azospirillum brasilense to Oxygen Stress by Cell-to-Cell Clumping and Flocculation
Authors: Bible Amber N. , Khalsa-Moyers Gurusahai K. , Mukherjee Tanmoy , Green Calvin S. , Mishra Priyanka , Purcell Alicia , Aksenova Anastasia , Hurst Gregory B. , Alexandre Gladys 
Published: September 2015

ABSTRACTThe ability of bacteria to monitor their metabolism and adjust their behavior accordingly is critical to maintain competitiveness in the environment. The motile microaerophilic bacteriumAzospirillum brasilensenavigates oxygen gradients by aerotaxis in order to locate low oxygen concentrations that can support metabolism. When cells are exposed to elevated levels of oxygen in their surroundings, motileA. brasilensecells implement an alternative response to aerotaxis and form transient clumps by cell-to-cell interactions. Clumping was suggested to represent a behavior protecting motile cells from transiently elevated levels of aeration. Using the proteomics of wild-type and mutant strains affected in the extent of their clumping abilities, we show that cell-to-cell clumping represents a metabolic scavenging strategy that likely prepares the cells for further metabolic stresses. Analysis of mutants affected in carbon or nitrogen metabolism confirmed this assumption. The metabolic changes experienced as clumping progresses prime cells for flocculation, a morphological and metabolic shift of cells triggered under elevated-aeration conditions and nitrogen limitation. The analysis of various mutants during clumping and flocculation characterized an ordered set of changes in cell envelope properties accompanying the metabolic changes. These data also identify clumping and early flocculation to be behaviors compatible with the expression of nitrogen fixation genes, despite the elevated-aeration conditions. Cell-to-cell clumping may thus license diazotrophy to microaerophilicA. brasilensecells under elevated oxygen conditions and prime them for long-term survival via flocculation if metabolic stress persists.
The effect of statins on average survival in randomised trials, an analysis of end point postponement
Authors: Kristensen Malene Lopez , Christensen Palle Mark , Hallas Jesper 
Published: September 2015

ObjectiveTo estimate the average postponement of death in statin trials.SettingA systematic literature review of all statin trials that presented all-cause survival curves for treated and untreated.InterventionStatin treatment compared to placebo.Primary outcome measuresThe average postponement of death as represented by the area between the survival curves.Results6 studies for primary prevention and 5 for secondary prevention with a follow-up between 2.0 and 6.1 years were identified. Death was postponed between −5 and 19 days in primary prevention trials and between −10 and 27 days in secondary prevention trials. The median postponement of death for primary and secondary prevention trials were 3.2 and 4.1 days, respectively.ConclusionsStatin treatment results in a surprisingly small average gain in overall survival within the trials’ running time. For patients whose life expectancy is limited or who have adverse effects of treatment, withholding statin therapy should be considered.