2,017 research outputs found
MiniAnDE: a reduced AnDE ensemble to deal with microarray data
This article focuses on the supervised classification of datasets with a
large number of variables and a small number of instances. This is the case,
for example, for microarray data sets commonly used in bioinformatics. Complex
classifiers that require estimating statistics over many variables are not
suitable for this type of data. Probabilistic classifiers with low-order
probability tables, e.g. NB and AODE, are good alternatives for dealing with
this type of data. AODE usually improves NB in accuracy, but suffers from high
spatial complexity since models, each with variables, are included in
the AODE ensemble. In this paper, we propose MiniAnDE, an algorithm that
includes only a small number of heterogeneous base classifiers in the ensemble,
i.e., each model only includes a different subset of the predictive
variables. Experimental evaluation shows that using MiniAnDE classifiers on
microarray data is feasible and outperforms NB and other ensembles such as
bagging and random forest
Identification of the HSP70-II gene in Leishmania braziliensis HSP70 locus: genomic organization and UTRs characterization
<p>Abstract</p> <p>Background</p> <p>The heat stress suffered by <it>Leishmania sp </it>during its digenetic life-cycle is a key trigger for its stage differentiation. In <it>Leishmania </it>subgenera two classes of <it>HSP70 </it>genes differing in their 3' UTR were described. Although the presence of <it>HSP70</it>-<it>I </it>genes was previously suggested in <it>Leishmania (Viannia) braziliensis</it>, <it>HSP70</it>-<it>II </it>genes had been reluctant to be uncovered.</p> <p>Results</p> <p>Here, we report the existence of two types of <it>HSP70 </it>genes in <it>L. braziliensis </it>and the genomic organization of the <it>HSP70 </it>locus. RT-PCR experiments were used to map the untranslated regions (UTR) of both types of genes. The 3' UTR-II has a low sequence identity (55-57%) when compared with this region in other <it>Leishmania </it>species. In contrast, the 5' UTR, common to both types of genes, and the 3' UTR-I were found to be highly conserved among all <it>Leishmania </it>species (77-81%). Southern blot assays suggested that <it>L. braziliensis </it><it>HSP70 </it>gene cluster may contain around 6 tandemly-repeated <it>HSP70</it>-<it>I </it>genes followed by one <it>HSP70</it>-<it>II </it>gene, located at chromosome 28. Northern blot analysis indicated that levels of both types of mRNAs are not affected by heat shock.</p> <p>Conclusions</p> <p>This study has led to establishing the composition and structure of the HSP70 locus of <it>L. braziliensis</it>, complementing the information available in the GeneDB genome database for this species. <it>L. braziliensis </it><it>HSP70 </it>gene regulation does not seem to operate by mRNA stabilization as occurs in other <it>Leishmania </it>species.</p
Suitability of the management of habitat complexity, acorn burial depth, and a chemical repellent for post-fire reforestation of oaks
Acorn sowing is a reforestation technique that can potentially render high-quality oak seedlings and high seedling survival, although it is often discarded due to high rates of seed predation. Predator activity can be modified by habitat complexity due to its effects on accessibility and protection for different predators. In this study we analysed how habitat complexity generated by different post-fire management treatments, sowing depth, and capsaicin (a chemical repellent) affect acorn predation by two guilds of post-dispersal predators that differ in size and foraging behaviour. We carried out two acorn predation experiments. In Experiment #1 we buried acorns at two depths (2 and 8 cm) in two post-fire burnt-wood management treatments of different habitat complexity, namely: (1) Salvage Logging (SL), where the burnt trunks were cut and piled and the branches were masticated (lower habitat complexity), and (2) Non-Intervention (NI), with no action after the fire and 100% of the trees naturally fallen by 2009, thus leaving a habitat with lying burnt logs and branches (higher habitat complexity). In Experiment #2 we repeated Experiment #1, with the addition of capsaicin as a mammal repellent treatment. Most acorns were consumed in both years (ca. 90%), mainly by rodents. In Experiment #1 predation by boars accounted for 4.1% of overall predation, and it was about twice as high in SL than in NI, likely due to the physical difficulty for large mammals to forage in an area with a complex structure created by lying logs and branches. In contrast, rodents consumed ca. 1.4 times more acorns in NI than in SL, which led to overall greater predation in NI in both experiments. This was likely due to the protection provided by the branches for the rodent community. Deeper burial reduced predation by small percentages, although in Experiment #1 it had a negligible effect in NI. Capsaicin did not reduce predation, and it reduced seedling emergence to half. This study suggests that habitat complexity created by trunks and branches reduced predation by wild boars, but favoured rodent acorn predation. We conclude that other methods for the protection of individual acorns need to be identified to increase the success of oak reforestation via seeding.Ministerio de Ciencia e InnovaciónComunidad de MadridMinisterio de Ciencia y EducaciónUnión Europe
Una propuesta para las prácticas de la materia "Teoría de Autómatas y Lenguajes Formales"
En este trabajo presentamos una propuesta para la realización de las prácticas relativas a la materia “Teoría de Autómatas y Lenguajes Formales”, basadas en el uso de distintos programas que permiten no sólo el diseño y prueba de los distintos modelos de autómata y gramática, sino también la interacción con el alumno para la resolución paso a paso de distintos problemas (minimización de autómatas finitos, conversiones entre distintos modelos de autómata y/o gramática, etc...)
Una Herramienta para la estimación del esfuerzo del estudiante de grado en ingeniería informática
En el marco de las nuevas titulaciones de Grado en
Ingeniería Informática, resulta muy conveniente
establecer algún tipo de mecanismo que nos permita
recoger información sobre la dedicación real de los
estudiantes a nuestras asignaturas. A nivel de asignatura,
esta información puede servir al profesorado
para determinar el grado de acierto de su planificación
temporal inicial. A un nivel más global, los datos
recogidos proporcionan a los coordinadores de curso
una idea de la carga total a la que está sometido el
estudiante, y contribuyen a la identificación de posibles
picos (o valles) de trabajo durante el cuatrimestre.
En este trabajo se describe la puesta en marcha de
un sistema, basado en encuestas, para el conocimiento
del esfuerzo de los estudiantes de Grado en Ingeniería
Informática de la Escuela Superior de Ingeniería
Informática de Albacete. También se presentan y
analizan algunos de los resultados obtenidos durante
el curso académico 2012/13.SUMMARY -- In the framework of new degrees in Computer Science,
it is desirable to establish some mechanism to
let us collect some information about our students'
commitment to our courses. On the subject level, this
information may be useful for the teaching staff to
determine the degree of success of this initial temporary
planning. In a high level point of view, the data
collected provide the course coordination with an
idea of the total workload of students and it contributes
to identify potential peaks (or valleys) of work
throughout the semester. This work presents a surveybased
system to obtain and register the efforts of our
Computer Engineering students from the School of
Computer Engineering of Albacete. It also introduces
and discusses some of the results obtained during the
academic year 2012/13
One-pot multicomponent green Hantzsch synthesis of 1,2-dihydropyridine derivatives with antiproliferative activity
A rapid route for obtaining unsymmetrical 1,2-dihydropyridines (1,2-DHPs) as opposed to 1,4-dihydropyridines (1,4-DHPs) has been achieved via a one-pot multicomponent Hantzsch reaction. A benign protocol has been developed for the preparation of various 1,2-dihydropyridine derivatives using heterogenized phosphotungstic acid on alumina support (40 wt %). High yields of over 75% have been accomplished in just 2–3.5 h after screening several heterogeneous catalysts and investigating the optimal reaction conditions. The catalyst chosen has passed the heterogeneity test and was shown to have the potential of being reused for up to 8 consecutive cycles before having a significant loss in activity. In addition, aromatic aldehydes gave the aforementioned regioisomer while the classical 1,4-DHPs were obtained when carrying out the reaction using aliphatic aldehydes. The preliminary study of the antiproliferative activity against human solid tumor cells demonstrated that 1,2-DHPs could inhibit cancer cell growth in the low micromolar range.peer-reviewe
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