5,146 research outputs found
Management and visualization of spatiotemporal information in GIS
Although Geographic Information Systems (GIS) have been recognised as the most
advanced technology for the management of geospatial information, they are still
unable to efficiently manage the temporal dimension. Originally this problem affeeted only the study and analysis of highly dynamic phenomena. Today's expansion of GIS technology, the ease to acquire and store geospatial data and the increased capacity of computing technologies to managc large amounl of data have contributed lo the propagation of this problem across the whole geospatial seclor.
The extended use of GIS in decision-making processes is increasing the demand for
tools able to manage and 10 analyse dynamic geospatial phenomena where the
temporal dimension is crucial. The only temporal model available in commercial
GIS packages is based on discretisation of temporal data. Changes are represented as
a succession of snapshots. The dynamics and what happens between those stages are
not registered. In addition, this approach presents severe problems due to
unavoidable multiplication of data volume, abundant redundancies, loss in query
efficiency and the impossibility of knowing when the exact timing of changes occurs.
Since the late 1980s and particularly in the 1990s, researching the temporal changes
and the conceptual and technological options available has been undertaken by the
GIS and DBMS sectors. The primary objective of the research presented in this
paper is the development of a model for the integration of temporal data with GIS.
The method adopted to achieve this objective is based on the combination of Time
Geography principies, its graphic language and dynamic segmentation techniques
used in GIS. Past research has demonstrated that the difficulty to integrate time with
GIS has its origin in the continuous nature of time. Dynamic segmentation in GIS
network analysis has the potential to provide the means for a time-GIS integration in a continuous manner. Lifelines, one of the main Time geography's graphic language
elements, has been modelled as a set of network segments where the dynamics in
attribute information has been attached to different time segments rather than
distance segments (for exampIe Euclidean or cost-based) as normally occurs in
dynamic segmentation. This paper summarises initial findings of the project. These
outcomes have the potential to improve the way the geospatial sector currently
handles temporal information. However, the static nature of current GIS technology
impedes an appropriate visualisation of dynamic temporal phenomena. To this
effect, the paper also explores the possibilities offered by multimedia techniques as a complement to GIS capabilities
Necrosis as Programmed Cell Death
The process of cell death is the mechanism through which organisms eliminate useless cells. Hence, it is a normal process that maintains homeostasis. Cell removal can be effectuated by several pathways that involve complex and regulated molecular events specific to each type of cell death. Diverse studies have evidenced different types of cell death: apoptosis, autophagy, and necrosis. This chapter presents a brief review of the apoptotic and autophagic cell death processes but focuses attention primarily on necrosis because it has previously been considered an accidental and uncontrolled form of cell death. More recent evidence, however, has shown that, under certain circumstances, necrosis is conducted by a controlled program called necroptosis, which is now included as a programmed cell death process
El Compostatge com a sistema de tractament de residus: compostatge de residus sòlids urbans - fangs de depuradores
L'augment de diferents residus orgànics i la problemàtica de la conservació
del medi ambient ha comportat l'estudi de tècniques d'aprofitament d'aquests residus i la seva posterior utilització.
Entre una de les nombroses tècniques, hi ha el "Compostatge" que dóna
com a producte final el "Compost" (utilitzable com a adob o esmena orgánica en agricultura).
En aquest treball pretenem de veure com podem realitzar aquest procés
amb el mínim de despeses econòmiques així com de trobar una manera adequada de treure una mostra representativa de la pila, de la durada del procés i del tractament de la mostra per tal de realitzar els anàlisis.The increase of different types of organic refuses and the problem of the
conservation of the natural environment has lead to the study of the techniques that make these refuses re-utilizable.
Among these techniques we find the compostage which final product is
known as the compost (utilizable in agriculture as fertilizer and as organic
amendmend).
In this study we try to explain how this process should be done being as
cheap as possible and we also try to find the better way to sample (the sample mus representative of the pile) the time the process takes and the teatment of the sample in order to be analyzed.El aumento de diferentes residuos orgánicos y la problemática de la
conservación del medio ambiente ha implicado el estudio de técnicas de
aprovechamiento de estos residuos y su posterior utilización.
Entre las numerosas técnicas está el "Compostage" que da como
producto final el "Compost" (utilizable como abono o enmienda orgánica en agricultura).
En este trabajo se pretende ver como realizar este proceso con el mínimo
coste, así como encontrar una forma adecuada de sacar una muestra representativa de la pila, duración del proceso y tratamiento de la muestra para realizar los análisis
Imaginario Social : una aproximación desde la obra de Michel Maffesoli
En este texto presentamos una revisión, -a modo de ejercicio de reflexión colectiva-, de la extensa producción bibliográfica de Michel Maffesoli, buscando articular desde los supuestos presentes en su obra, la noción de imaginario social. Para comprender el contexto de producción de este sociólogo francés, hemos comenzado por hacer una breve revisión de sus principales trabajos e influencias teóricas. Posteriormente hemos centrado la reflexión sobre sus textos fundamentales: El conocimiento ordinario, La orgía, El tiempo de las tribus, Elogio de la razón sensible y El instante eterno. Finalmente, nos aproximamos a la intersección de su obra con el imaginario social de acuerdo a cuatro categorías temáticas propuestas por Enrique Carretero (2003): el significado de la utopía, la problemática en torno a la modernidad, la integración simbólica del neotribalismo y la legitimidad del orden social.In the following text we display a review, -a sort of collective reflection exercise-, regarding the extensive bibliographic production of Michel Maffesoli, trying to articulate the notion of social imaginary departing from the suppositions present in Maffesoli's work. In order to understand the production context of this French sociologist, we began by a brief review of his main work as well as other theoretical influences. Afterwards, his fundamental texts are the subject to a reflection: Ordinary Knowledge, The orgy, The Time of the Tribes, Praise of a Sensible Reason, and The Eternal Instant. Finally, several elements studied were integrated in an approach to the notion of social imaginary, facing four thematic categories following Enrique Carretero's (2003) proposals: utopia's meaning, problems concerning modernity, symbolic integration of neotribalism, and the legitimacy of social order
Room-temperature polariton repulsion and ultra-strong coupling for a non-trivial topological one-dimensional tunable Fibonacci-conjugated porous-Silicon photonic quasi-crystal showing quasi bound-states-in-the-continuum
Room temperature strong coupling from CdSeS/Zn quantum-dots embedded into a
tunable porous-silicon Fibonacci-conjugated array could be observed when
exciton's energy was tuned either to the photonic-edge or the defect in the
middle of the pseudo-bandgap region of the 1D cavity. Both, the photonic-edge
and the defect could be identified as topological edge modes and
quasi-bound-states-in-the-continuum, where large density of states and field
localization over a wider bandwidth produce a broadband Purcell enhancement,
helping to optimize the coupling among the exciton and the 1D photonic
quasi-crystal despite the natural difficulty to make the quantum dots to
penetrate the cavity pores. A clear repulsion among polaritons, amounting to
almost 8 meV for in-plane k values when the cavity energy is larger than the
exciton one (blue k-detuning), was measured when increasing the incident light
fluence, marking the potential of this non-trivial topological array for
achieving polariton quantum blockade. Evidence for ultra-strong coupling, where
a shift as large as 20 meV, could be found when the defect of the
pseudo-bandgap region of the cavity was tuned to the exciton
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