Massimo Donà, Misterio grande. Filosofia di Giacomo Leopardi

Massimo Donà, Misterio grande. Filosofia di Giacomo Leopardi. Milà: Bompiani, 2013, 316 pp

"La Querelle des anciens et des moderns": Leopardi i la via perduda del romanticisme alemany

El marc interpretatiu d’aquest article parteix de l’establiment de dos bàndols filosòfics: per una banda, Goethe i Leopardi, en tant que respectuosos amb el límit de la natura, i per l’altra, els romàntics i l’idealisme absolut de Hegel, en tant que irrespectuosos amb els límits de la natura. El salt teòric a partir del qual gira aquest article, consisteix a estendre l’enfrontament explícit que Giacomo Leopardi va mantenir contra el romanticisme vers l’idealisme absolut de Hegel. I és que hom es planteja el fet que ambdós moviments van en contra de la veritat en tant que revelació. La veritat leopardiana es revela mitjançant la imaginació o les il•lusions, la qual cosa el porta a depassar el conflicte entre els anciens i els modernes en tant que models. I és que no hi pot haver models perquè la veritat no és pas un objecte

Amphioxus: a peaceful anchovy fillet to illuminate Chordate Evolution (II)

The genome of the amphioxus is on the horizon. With Linda Holland and Jeremy Gibson-Brown at the forefront, with all the amphioxus community behind, and with the Joint Genome Institute, the amphioxus genome will see the light this year, 2006. Hope that it will reflect the “prototypical” preduplicative genome of vertebrates. It may answer definitively what the human genome did not: Are we vertebrates octaploid? Will it shed light on the novelties that helped non-chordates to be chordates? And more, will amphioxus, with a simpler genome, be developed to a senior “experimental model system”, allowing the testing of molecular functions in a non-duplicated genome background and allowing genetic modification to “recapitulate” evolution? Thanks to an outstanding collaboration between labs, the laboratory culture of amphioxus is underway after years of hard work in the field. 2007 looks promising for amphioxus research

Genesis and evolution of the Evx and Mox genes and the extended Hox and ParaHox gene clusters

BACKGROUND: Hox and ParaHox gene clusters are thought to have resulted from the duplication of a ProtoHox gene cluster early in metazoan evolution. However, the origin and evolution of the other genes belonging to the extended Hox group of homeobox-containing genes, that is, Mox and Evx, remains obscure. We constructed phylogenetic trees with mouse, amphioxus and Drosophila extended Hox and other related Antennapedia-type homeobox gene sequences and analyzed the linkage data available for such genes. RESULTS: We claim that neither Mox nor Evx is a Hox or ParaHox gene. We propose a scenario that reconciles phylogeny with linkage data, in which an Evx/Mox ancestor gene linked to a ProtoHox cluster was involved in a segmental tandem duplication event that generated an array of all Hox-like genes, referred to as the 'coupled' cluster. A chromosomal breakage within this cluster explains the current composition of the extended Hox cluster (with Evx, Hox and Mox genes) and the ParaHox cluster. CONCLUSIONS: Most studies dealing with the origin and evolution of Hox and ParaHox clusters have not included the Hox-related genes Mox and Evx. Our phylogenetic analyses and the available linkage data in mammalian genomes support an evolutionary scenario in which an ancestor of Evx and Mox was linked to the ProtoHox cluster, and that a tandem duplication of a large genomic region early in metazoan evolution generated the Hox and ParaHox clusters, plus the cluster-neighbors Evx and Mox. The large 'coupled' Hox-like cluster EvxHox/MoxParaHox was subsequently broken, thus grouping the Mox and Evx genes to the Hox clusters, and isolating the ParaHox cluster

Particle Density Estimation with Grid-Projected Adaptive Kernels

The reconstruction of smooth density fields from scattered data points is a procedure that has multiple applications in a variety of disciplines, including Lagrangian (particle-based) models of solute transport in fluids. In random walk particle tracking (RWPT) simulations, particle density is directly linked to solute concentrations, which is normally the main variable of interest, not just for visualization and post-processing of the results, but also for the computation of non-linear processes, such as chemical reactions. Previous works have shown the superiority of kernel density estimation (KDE) over other methods such as binning, in terms of its ability to accurately estimate the "true" particle density relying on a limited amount of information. Here, we develop a grid-projected KDE methodology to determine particle densities by applying kernel smoothing on a pilot binning; this may be seen as a "hybrid" approach between binning and KDE. The kernel bandwidth is optimized locally. Through simple implementation examples, we elucidate several appealing aspects of the proposed approach, including its computational efficiency and the possibility to account for typical boundary conditions, which would otherwise be cumbersome in conventional KDE

El petit amfiox: el miratge de l'origen dels vertebrats

L'origen dels vertebrats és un dels centres d'interès de molts científics i de la societat, i el nostre animal favorit, el petit i amigable amfiox, fa més d'un segle que ocupa aquesta posició privilegiada, i reflecteix en un miratge, com a fòssil vivent, el que va ocórrer en aquell transcendental moment de l'evolució. No és només morfològicament el representant viu de l'ancestre de tots els cordats, sinó que a més posseeix un genoma preduplicatiu, un model en versió simple del genoma de tots els vertebrats, incloent-hi l'humà. L'anàlisi del genoma de l'amfiox ha permès clarificar l'origen del nostre genoma propi, alhora que l'ha situat en una posició clau per entendre l'origen i funcionament de famílies i xarxes gèniques importants per al desenvolupament embrionari i la fisiologia. A més, els avenços tècnics en la reproducció i experimentació permeten raonadament somiar a resoldre els secrets dels nostres orígens i del funcionament del genoma.The little amphious: a mirage to the origen of vertebrates. The origin of vertebrates is one of the top interests for many scientists and the society, and our favorite animal has occupied this privileged position for more than a century, reflecting in a mirage, as a living fossil, what occurred in this critical landmark of evolution. It is not only morphologically the closest living relative of Chordates, but also possesses a preduplicative genome, a simple model for the genome of all vertebrates, including humans. The analysis of the amphioxus genome has served to clarify the origin of our own genome, and as showed it is in a key position to understand the origin and functioning of gene families and gene networks critical for embryonic development and physiology. Besides, technical advances in its reproduction and experimentation make plausible to dream in illuminating the secrets of our origins and the functioning of the genome

The value of satellite remote sensing soil moisture data and the DISPATCH algorithm in irrigation fields

Soil moisture measurements are needed in a large number of applications such as hydro-climate approaches, watershed water balance management and irrigation scheduling. Nowadays, different kinds of methodologies exist for measuring soil moisture. Direct methods based on gravimetric sampling or time domain reflectometry (TDR) techniques measure soil moisture in a small volume of soil at few particular locations. This typically gives a poor description of the spatial distribution of soil moisture in relatively large agriculture fields. Remote sensing of soil moisture provides widespread coverage and can overcome this problem but suffers from other problems stemming from its low spatial resolution. In this context, the DISaggregation based on Physical And Theoretical scale CHange (DISPATCH) algorithm has been proposed in the literature to downscale soil moisture satellite data from 40 to 1&thinsp;km resolution by combining the low-resolution Soil Moisture Ocean Salinity (SMOS) satellite soil moisture data with the high-resolution Normalized Difference Vegetation Index (NDVI) and land surface temperature (LST) datasets obtained from a Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. In this work, DISPATCH estimations are compared with soil moisture sensors and gravimetric measurements to validate the DISPATCH algorithm in an agricultural field during two different hydrologic scenarios: wet conditions driven by rainfall events and wet conditions driven by local sprinkler irrigation. Results show that the DISPATCH algorithm provides appropriate soil moisture estimates during general rainfall events but not when sprinkler irrigation generates occasional heterogeneity. In order to explain these differences, we have examined the spatial variability scales of NDVI and LST data, which are the input variables involved in the downscaling process. Sample variograms show that the spatial scales associated with the NDVI and LST properties are too large to represent the variations of the average soil moisture at the site, and this could be a reason why the DISPATCH algorithm does not work properly in this field site.</p