Cluster recognition in spatial-temporal sequences: The case of forest fires

Forest fire sequences can be modelled as a stochastic point process where events are characterized by their spatial locations and occurrence in time. Cluster analysis permits the detection of the space/time pattern distribution of forest fires. These analyses are useful to assist fire-managers in identifying risk areas, implementing preventive measures and conducting strategies for an efficient distribution of the firefighting resources. This paper aims to identify hot spots in forest fire sequences by means of the space-time scan statistics permutation model (STSSP) and a geographical information system (GIS) for data and results visualization. The scan statistical methodology uses a scanning window, which moves across space and time, detecting local excesses of events in specific areas over a certain period of time. Finally, the statistical significance of each cluster is evaluated through Monte Carlo hypothesis testing. The case study is the forest fires registered by the Forest Service in Canton Ticino (Switzerland) from 1969 to 2008. This dataset consists of geo-referenced single events including the location of the ignition points and additional information. The data were aggregated into three sub-periods (considering important preventive legal dispositions) and two main ignition-causes (lightning and anthropogenic causes). Results revealed that forest fire events in Ticino are mainly clustered in the southern region where most of the population is settled. Our analysis uncovered local hot spots arising from extemporaneous arson activities. Results regarding the naturally-caused fires (lightning fires) disclosed two clusters detected in the northern mountainous area.

Comparative genomics of ParaHox clusters of teleost fishes: gene cluster breakup and the retention of gene sets following whole genome duplications.

BACKGROUND: The evolutionary lineage leading to the teleost fish underwent a whole genome duplication termed FSGD or 3R in addition to two prior genome duplications that took place earlier during vertebrate evolution (termed 1R and 2R). Resulting from the FSGD, additional copies of genes are present in fish, compared to tetrapods whose lineage did not experience the 3R genome duplication. Interestingly, we find that ParaHox genes do not differ in number in extant teleost fishes despite their additional genome duplication from the genomic situation in mammals, but they are distributed over twice as many paralogous regions in fish genomes. RESULTS: We determined the DNA sequence of the entire ParaHox C1 paralogon in the East African cichlid fish Astatotilapia burtoni, and compared it to orthologous regions in other vertebrate genomes as well as to the paralogous vertebrate ParaHox D paralogons. Evolutionary relationships among genes from these four chromosomal regions were studied with several phylogenetic algorithms. We provide evidence that the genes of the ParaHox C paralogous cluster are duplicated in teleosts, just as it had been shown previously for the D paralogon genes. Overall, however, synteny and cluster integrity seems to be less conserved in ParaHox gene clusters than in Hox gene clusters. Comparative analyses of non-coding sequences uncovered conserved, possibly co-regulatory elements, which are likely to contain promoter motives of the genes belonging to the ParaHox paralogons. CONCLUSION: There seems to be strong stabilizing selection for gene order as well as gene orientation in the ParaHox C paralogon, since with a few exceptions, only the lengths of the introns and intergenic regions differ between the distantly related species examined. The high degree of evolutionary conservation of this gene cluster's architecture in particular - but possibly clusters of genes more generally - might be linked to the presence of promoter, enhancer or inhibitor motifs that serve to regulate more than just one gene. Therefore, deletions, inversions or relocations of individual genes could destroy the regulation of the clustered genes in this region. The existence of such a regulation network might explain the evolutionary conservation of gene order and orientation over the course of hundreds of millions of years of vertebrate evolution. Another possible explanation for the highly conserved gene order might be the existence of a regulator not located immediately next to its corresponding gene but further away since a relocation or inversion would possibly interrupt this interaction. Different ParaHox clusters were found to have experienced differential gene loss in teleosts. Yet the complete set of these homeobox genes was maintained, albeit distributed over almost twice the number of chromosomes. Selection due to dosage effects and/or stoichiometric disturbance might act more strongly to maintain a modal number of homeobox genes (and possibly transcription factors more generally) per genome, yet permit the accumulation of other (non regulatory) genes associated with these homeobox gene clusters.

Aversive Stimuli and Functional Networks of Fear Learning in PTSD : 734

Background: One characteristic of post traumatic stress disorder is an inability to adapt to a safe environment i.e. to change behavior when predictions of adverse outcomes are not met. Recent studies have also indicated that PTSD patients have altered pain processing, with hyperactivation of the putamen and insula to aversive stimuli (Geuze et al, 2007). The present study examined neuronal responses to aversive and predicted aversive events. Methods: Twenty-four trauma exposed non-PTSD controls and nineteen subjects with PTSD underwent fMRI imaging during a partial reinforcement fear conditioning paradigm, with a mild electric shock as the unconditioned stimuli (UCS). Three conditions were analyzed: actual presentations of the UCS, events when a UCS was expected, but omitted (CS+), and events when the UCS was neither expected nor delivered (CS-). Results: The UCS evoked significant alterations in the pain matrix consisting of the brainstem, the midbrain, the thalamus, the insula, the anterior and middle cingulate and the contralateral somatosensory cortex. PTSD subjects displayed bilaterally elevated putamen activity to the electric shock, as compared to controls. In trials when USC was expected, but omitted, significant activations were observed in the brainstem, the midbrain, the anterior insula and the anterior cingulate. PTSD subjects displayed similar activations, but also elevated activations in the amygdala and the posterior insula. Conclusions: These results indicate altered fear and safety learning in PTSD, and neuronal activations are further explored in terms of functional connectivity using psychophysiological interaction analyses.

Community cluster of meningococcal disease by Neisseria meningitidis serogroup C in Andalusia, Spain, March to May 2011.

Between March and May of 2011, a cluster of three fatal cases of meningococcal sepsis occurred in Andalusia, Spain, in a municipality with a population of around 20,000 inhabitants. The cases were in their mid-teens to early thirties and were notified to the epidemiological surveillance system of Andalusia (Sistema de Vigilancia Epidemiológica de Andalucía, SVEA) during a 68-day period from March through May 2011. All three were infected with the same strain of Neisseria meningitidis serogroup C genosubtype VR1:5-1;VR2:10-8. None of the cases had been previously vaccinated against N. meningitidis serogroup C. Antibiotic post-exposure chemoprophylaxis was administered to close contacts of every diagnosed case. Once the cluster was confirmed, the local population was informed through the media about the control measures taken by the health authorities. The vaccination history against N. meningitidis serogroup C of the population under 25 years-old in the municipality was checked. Vaccination was offered to unimmunised individuals younger than 25 years of age and an additional dose of vaccine was offered to those who had been vaccinated between 2000 and 2006 with a vaccination schedule of three doses before the first year of age. No further cases occurred since the beginning of these actions.

Spatial learning by rats across visually disconnected environments

Experiments were designed to examine some properties of spatial representations in rats. Adult subjects were trained to escape through a hole at a fixed position in a large circular arena (see Schenk 1989). The experiments were conducted in the dark, with a limited number of controlled visual light cues in order to assess the minimal cue requirement for place learning. Three identical light cues (shape, height and distance from the table) were used. Depending on the condition, they were either permanently on, or alternatively on or off, depending on the position of the rat in the field. Two questions were asked: a) how many identical visual cues were necessary for spatial discrimination in the dark, and b) could rats integrate the relative positions of separate cues, under conditions in which the rat was never allowed to perceive all three cues simultaneously. The results suggest that rats are able to achieve a place discrimination task even if the three cues necessary for efficient orientation can never be seen simultaneously. A dissociation between the discrimination of the spatial position of the goal and the capacity to reach it by a direct path suggests that a reduced number of cues might require prolonged locomotion to allow an accurate orientation in the environment.

Indirect effects of peri-and postnatal choline treatment on place-learning abilities in rat.

This work was aimed at analyzing the effects of perinatal choline supplementation on the development of spatial abilities and upon adult performance. Choline supplementation (3.5 g/L in 0.02 M saccharin solution in tap water) was maintained for two weeks before birth and for up to four weeks postnatally. Additional supplementation was maintained from the fifth to the tenth week postnatally. Spatial-learning capacities were studied at the ages of 26, 65, or 80 days in a circular swimming pool (Morris place-navigation task) and at the age of 7 months in a homing arena. Treatment effects were found in both juvenile and adult rats, and thus persisted for several months after the cessation of the supplementation. The choline supplementation improved the performance in the water maze in a very selective manner. The most consistent effect was a reduction in the latency to reach a cued platform at a fixed position in space, whereas the improvement was limited when the platform was invisible and had to be located relative to distant cues only. However, after removal of the goal cue, the treated rats showed a better retention of the training position than did the control rats. A similar effect was observed in a dry-land task conducted in the homing arena. The choline supplementation thus induced a significant improvement of spatial memory. But since this effect was only evident following training with a salient cue, it might be regarded as an indirect effect promoted by an optimal combination of cue guidance with a place strategy.

The interactional space in CLIL (Content and Language Integrated Learning) and EFL (English as a Foreign Language) classrooms

Aquest estudi pretén investigar els intercanvis verbals mestre/a – aprenent(s) en dos contextos d'instrucció diferents: classes amb un enfocament AICLE (Aprenentatge Integrat de Continguts Curriculars i Llengua Estrangera) on s’aprenen continguts no lingüístics a través de l’anglès, per una banda, i classes 'tradicionals' d'anglès com a llengua estrangera, on l’anglès és alhora objecte d’estudi i vehicle de comunicació, per una altra banda. Més concretament, les preguntes que formula el/la mestre/a, la producció oral dels aprenents i el 'feedback' del/de la mestre/a en els episodis d’atenció a la forma s’han estudiat a la llum de les principals teories provinents del camp de l’Adquisició de Segones Llengües (SLA) per tal de demostrar el seu paper en l’aprenentatge de l’anglès. El corpus de dades prové de l’enregistrament de 7 sessions AICLE i d'11 sessions EFL enregistrades en format àudio i vídeo en dos centres públics d’Educació Primària (EP) de Catalunya. A cadascuna de les escoles, el/la mateix/a mestre/a és l’encarregat/da dels dos tipus d’instrucció amb el mateix grup d’aprenents (10-11 anys d’edat), fet que permet eliminar variables individuals com l'aptitud dels aprenents o l'estil del/de la mestre/a.Els resultats mostren un cert nombre de similituds discursives entre AICLE i EFL donat que ambdós enfocaments tenen lloc en el context-classe amb unes característiques ben definides. Tal com apunta la recerca realitzada en aquest camp, la instrucció AICLE reuneix un seguit de condicions idònies per un major desenvolupament dels nivells de llengua anglesa més enllà de les classes ‘tradicionals’ d’anglès. Malgrat això, aquest estudi sembla indicar que el potencial d'AICLE pel que fa a facilitar una exposició rica a l’anglès i una producció oral significativa no s’explota degudament. En aquest sentit, els resultats d’aquest estudi poden contribuir a la formació dels futurs professors d'AICLE si es busca l’assoliment d’una complementarietat d’ambdós contextos amb l’objectiu últim de millorar els nivells de domini de la llengua anglesa.

MENTAL IMAGERY IN PERCEPTUAL LEARNING

L'imagerie mentale est définie comme une expérience similaire à la perception mais se déroulant en l'absence d'une stimulation physique. Des recherches antérieures ont montré que l'imagerie mentale améliore la performance dans certains domaines, comme par exemple le domaine moteur. Cependant, son rôle dans l'apprentissage perceptif n'a pas encore été étudié. L'apprentissage perceptif correspond à l'amélioration permanente des performances suite à la répétition de la même tâche. Cette thèse présente une série des résultats empiriques qui montrent que l'apprentissage perceptif peut aussi être achevé en l'absence des stimuli physiques. En effet, imaginer des stimuli visuels amène à une meilleure performance avec les stimuli réels. Donc, les processus sous-jacents l'apprentissage perceptif ne sont pas uniquement déclenchés par les stimuli sensoriels, mais également par des signaux internes. En plus, l'apprentissage perceptif à travers l'imagerie mentale ne se réalise que seule-ment quand les stimuli ne sont pas (complètement) présents, mais gaiement quand les stimuli montrés ne sont pas utiles quant à la résolution de la tâche. - Mental imagery is described as an experience that resembles pereeptnal ex-perience but which occurs in the absence ef a physical stimulation. Despite its beneficial effects in, among others, motor performance, the role of mental imagery m perceptual learning has not yet been addressed. Here we focus on a specific sensory modality: vision. Perceptual learning is the ability to improve perception in a stable way through the repetition of a given task Here I demonstrate by a series of empirical results that a perceptual improve¬ment can also occur in the absence of a stimulation. Imagining visual stimuli is sufficient for successful perceptual learning. Hence, processes underlying perceptual learning are not only stimulus-driven but can also be driven by internally generated signals. Moreover, I also show that perceptual learning via mental imagery can occur not only when physical stimuli are (partially) absent, but also in conditions where stimuli are uninformative with respect to the task that has to be learned.

Étude de l'influence de l'activité inflammatoire liée au TNFα sur les altérations cognitives et comportementales et le dépôt de plaques β amyloïdes chez la souris

Résumé Les mutations du gène APP (amyloïde de la protéine de précurseur) sur le chromosome 21 mènent à une surproduction de protéines β amyloïdes dans la maladie d'Alzheimer (MA). Il existe donc un consensus impliquant la cascade amyloïde dans la genèse et le développement de la MA. C'est pourquoi, afin d'évaluer l'hypothèse de la cascade inflammatoire de la MA, on combine des manipulations génétiques chez des modèles de souris transgéniques avec des traitements anti-inflammatoires. Les animaux porteurs d'une mutation génétique induite permettent d'évaluer le rôle de certains gènes dans le développement de la maladie. Pour ce faire j'ai étudié les performances de différentes cohortes de souris soumises à un ensemble de trois épreuves comportementales complémentaires ; la première étudiant les conduites exploratoires, la deuxième évaluant la capacité de l'animal à effectuer un apprentissage de lieu et la troisième explorant l'efficacité des animaux dans une tâche dite d'élimination. Enfin, une évaluation complémentaire a été fondée sur le répertoire des troubles du comportement des animaux. Chez les animaux APP homozygotes, l'organisation de la mémoire se dégrade et se modifie avec l'âge. Chez ces animaux, le déficit des mémoires de références et de travail se manifeste déjà chez les souris jeunes (dès l'âge de 50 jours).De plus, il est apparu un certain nombre de troubles comportementaux. Enfin les APP homozygotes sont ceux qui ont le plus de dépôt de plaques amyloïdes localisé dans l'hippocampe. Chez les animaux APP hétérozygotes, tant la mémoire de référence, utilisée au cours d'un apprentissage de lieu, que la mémoire de travail permettant d'éviter des bras déjà visités, ne sont affectées que chez les sujets de 15 mois. De plus, tous les troubles du comportement sont présents à 15 mois, mais de manière moins intense que chez les animaux APP homozygotes. Un traitement anti-TNF administré aux APP hétérozygotes n'a pas permis d'améliorer leur performance mais a un effet bénéfique sur les troubles du comportement. Enfin, le pourcentage des dépôts de plaques a été estimé à trois fois moins élevé chez ces animaux hétérozygotes de 16 mois que chez les APP homozygotes de 8 mois. Chez les animaux APP hétérozygotes dont le gène TNFα est bloqué, les mémoires de travail et de référence sont altérées déjà à l'âge de 6 mois, en dépit du blocage de l'expression de TNF. Ces jeunes animaux ont même une capacité cognitive inférieure à celle des animaux hétérozygotes APP, en gardant toutefois leur activité et performance exploratoires intactes. Ainsi, il semble que le blocage de l'expression du gène TNFα chez des souris APP n'influence pas leurs capacités cognitives mais permet, d'une part, d'éviter l'apparition des troubles du comportement et d'autre part, ralentit le processus du déclin cognitif. Enfin, le pourcentage de plaques amyloïdes a été évalué à deux fois plus élevés pour les KO TNF-α APP hétérozygotes de 15 mois par rapport à des APP hétérozygotes sans traitement du même âge. Chez les animaux APP hétérozygotes surexprimant le TNFα, cette association génétique péjore la performance cognitive comparée à celle des APP homozygotes. Ces animaux ont une altération des mémoires de travail et de référence équivalente à celle retrouvée chez des APP homozygotes. Un traitement anti-inflammatoire administré à ces souris n'améliore pas la capacité cognitive mais permet d'une part, d'éviter l'apparition des troubles comportementaux, et d'autre part, d'entraîner la presque disparition des plaques amyloïdes. Abstract Mutations on the amyloid precursor protein (APP) gene on chromosome 21 lead to an overproduction of β amyloid in both human early onset familial Alzheimer's Disease (AD) and transgenic (TG) mice. On the other hand, inflammatory responses in the brain seem to contribute to the genesis and evolution of neurodegenerative damage. To study the influence of inflammatory factors - especially TNFα - on brain amyloid and behavioural components, TG mice expressing mutant amyloid precursor protein were treated with anti-TNFα antibody and compared with controls injected with PBS buffer or human globulins, as well as with APP mice knockout for the TNFα gene. The APP/V717 mutation leads to a brain deposit of amyloid and to significant behavioural deficits in both homozygous at different ages and heterozygous only at 15 months. The percentage of amyloid is almost triple in APP+/+ than in APP+/- animals, indicating a gene dosage effect. There is no significant effect of an anti-TNF treatment on the deposit of brain amyloid nor spatial learning capabilities. Transgenic mice show also stereotyped behaviour but the anti-TNF treatment decreases the production of stereotypies. The blockade of gene TNFα seems several cognitive alterations and increases the production of amyloid in APP mice at 15 months; but this combination allows to avoid the appearance of stereotyped behavior and in addition, the process of the cognitive decline slows down. Tg6074 mice (overexpressing TNF) increase deleterious effects on behavioural adaptive resources. Treatment with anti-TNF doesn't show changes in cognitive performances but seems to increase the production of amyloid and the stereotyped behaviour.

Diseño de una herramienta de e-learning para el área de cirugía traumatológica

Este artículo trata, en primer lugar, de analizar el estado actual de las herramientas de e-learning relacionadas y aplicadas en el área de cirugía traumatológica, presentando las herramientas disponibles en la actualidad como vídeos, audios, simuladores de realidad virtual, pacientes virtuales, LMS, entre otras; para, a continuación, describir el diseño de una herramienta en la que los componentes cumplan con los criterios de integración, interactividad, estandarización y asegure la reutilización. Como conclusión, se valora positivamente el diseño de una herramienta totalmente de código abierto que incorpora componentes de LMCS, repositorios de objetos, pacientes virtuales, simuladores hápticos de realidad virtual y objetos educativos, entre otros. Finalmente se recomienda implementar y comprobar la utilidad de la herramienta propuesta en la formación y entrenamiento de cirujanos traumatólogos.

Electronic voting system for computer supported collaborative learning

The EVS4CSCL project starts in the context of a Computer Supported Collaborative Learning environment (CSCL). Previous UOC projects created a CSCL generic platform (CLPL) to facilitate the development of CSCL applications. A discussion forum (DF) was the first application developed over the framework. This discussion forum was different from other products on the marketplace because of its focus on the learning process. The DF carried out the specification and elaboration phases from the discussion learning process but there was a lack in the consensus phase. The consensus phase in a learning environment is not something to be achieved but tested. Common tests are done by Electronic Voting System (EVS) tools, but consensus test is not an assessment test. We are not evaluating our students by their answers but by their discussion activity. Our educational EVS would be used as a discussion catalyst proposing a discussion about the results after an initial query or it would be used after a discussion period in order to manifest how the discussion changed the students mind (consensus). It should be also used by the teacher as a quick way to know where the student needs some reinforcement. That is important in a distance-learning environment where there is no direct contact between the teacher and the student and it is difficult to detect the learning lacks. In an educational environment, assessment it is a must and the EVS will provide direct assessment by peer usefulness evaluation, teacher marks on every query created and indirect assessment from statistics regarding the user activity.

Learning about Distributed Systems

This paper presents the "state of the art" about distributed systems and applications and it's focused on teaching about these systems. It presents different platforms where to run distributed applications and describes some development toolkits whose can be used to develop prototypes, practices and distributed applications. It also presents some existing distributed algorithms useful for class practices, and some tools to help managing distributed environments. Finally, the paper presents some teaching experiences with different approaches on how to teach about distributed systems.

An empirical study of machine learning techniques applied to image watermarking

A study of how the machine learning technique, known as gentleboost, could improve different digital watermarking methods such as LSB, DWT, DCT2 and Histogram shifting.

Forest fires cluster detection with space-time scan statistics

Forest fires are defined as uncontrolled fires often occurring in wildland areas, but that can also affect houses or agricultural resources. Causes are both natural (e.g.,lightning phenomena) and anthropogenic (human negligence or arsons).Major environmental factors influencing the fire ignition and propagation are climate and vegetation. Wildfires are most common and severe during drought period and on windy days. Moreover, under water-stress conditions, which occur after a long hot and dry period, the vegetation is more vulnerable to fire. These conditions are common in the United State and Canada, where forest fires represent a big problem. We focused our analysis on the state of Florida, for which a big dataset on forest fires detection is readily available. USDA Forest Service Remote Sensing Application Center, in collaboration with NASA-Goddard Space Flight Center and the University of Maryland, has compiled daily MODIS Thermal Anomalies (fires and biomass burning images) produced by NASA using a contextual algorithm that exploits the strong emission of mid-infrared radiation from fires. Fire classes were converted in GIS format: daily MODIS fire detections are provided as the centroids of the 1 kilometer pixels and compiled into daily Arc/INFO point coverage.