Search

© 2010. The American Astronomical Society. This work was supported by the Spanish Programa Nacional de Astronomía y Astrofísica through the project numbers AYA2006-12955, AYA2006-02358, and AYA 2006-15698-C02-02. This work was partially funded by the Spanish MEC under the Consolider-Ingenio 2010 Program grant CSD2006-00070: First Science with the GTC (http://www.iac.es/consolider-ingenio-gtc/).This work is based on HST/ACS images from GOODS HST Treasury Program, which is supported by NASA through grants HST-GO-09425.01-A and HST-GO-09583.01, and in part on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, Caltech under NASA contract 1407.P. G. P. G. acknowledges support from the Ramón y Cajal Program financed by the Spanish Government and the European Union., We study the evolution of galaxy structure since z ~ 1 to the present. From a Great Observatories Origins Deep Survey South (GOODS-S) multi-band catalog, we define (blue) luminosity- and mass-weighted samples, limited by MB ≤ –20 and M sstarf ≥ 1010 M ☉, comprising 1122 and 987 galaxies, respectively. We extract early-type (ET; E/S0/Sa) and late-type (LT; Sb-Irr) subsamples by their position in the concentration-asymmetry plane, in which galaxies exhibit a clear bimodality. We find that the ET fraction, f ET, rises with cosmic time, with a corresponding decrease in the LT fraction, f LT, in both luminosity- and mass-selected samples. However, the evolution of the comoving number density is very different: the decrease in the total number density of MB ≤ –20 galaxies since z = 1 is due to the decrease in the LT population, which accounts for ~75% of the total star formation rate in the range under study, while the increase in the total number density of M sstarf ≥ 1010 M ☉ galaxies in the same redshift range is due to the evolution of ETs. This suggests that we need a structural transformation between LT galaxies that form stars actively and ET galaxies in which the stellar mass is located. Comparing the observed evolution with the gas-rich major merger rate in GOODS-S, we infer that only ~20% of the new ET galaxies with M sstarf ≥ 1010 M ☉ appeared since z ~ 1 can be explained by this kind of mergers, suggesting that minor mergers and secular processes may be the driving mechanisms of the structural evolution of intermediate-mass (M sstarf ~ 4 × 1010 M ☉) galaxies since z ~ 1., Programa Nacional de Astronomía y Astrofísica (MICINN), España, Ministerio de Educación y Ciencia (MEC), España, National Aeronautics and Space Administration (NASA), Gobierno de España, Unión Europea (UE), Programa Consolider-Ingenio (MINECO), España, Ministerio de Economía y Competitividad (MINECO), España, GOODS HST Treasury Program (NASA), Jet Propulsion Laboratory, Caltech, Programa Ramón y Cajal, Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

BACKGROUND: Recently, different software has been developed to automatically analyze multiple intracranial pressure (ICP) parameters, but the suggested methods are frequently complex and have no clinical correlation. The objective of this study was to assess the clinical value of a new morphological classification of the cerebrospinal fluid pulse pressure waveform (CSFPPW), comparing it to the elastance index (EI) and CSF-outflow resistance (Rout), and to test the efficacy of an automatic ICP analysis. METHODS: An artificial neural network (ANN) was trained to classify 60 CSFPPWs in four different classes, according to their morphology, and its efficacy was compared to an expert examiner's classification. The morphology of CSFPPW, recorded in 60 patients at baseline, was compared to EI and Rout calculated at the end of an intraventricular infusion test to validate the utility of the proposed classification in patients' clinical evaluation. RESULTS: The overall concordance in CSFPPW classification between the expert examiner and the ANN was 88.3 %. An elevation of EI was statistically related to morphological class' progression. All patients showing pathological baseline CSFPPW (class IV) revealed an alteration of CSF hydrodynamics at the end of their infusion test. CONCLUSIONS: The proposed morphological classification estimates the global ICP wave and its ability to reflect or predict an alteration in CSF hydrodynamics. An ANN can be trained to efficiently recognize four different CSF wave morphologies. This classification seems helpful and accurate for diagnostic use.

Quantitative morphology has already been shown by these authors to describe the processes of cytoskeletal disorganisation and re-organisation related to the exposure of cultured cells to xenobiotics [G F Crosta, C Urani, L Fumarola, Estimating Structural Damage of the Cytoskeleton by means of Morphological Descriptors, Proc. SPIE 5461 Biophotonics New Frontier: From Genome to Proteome, M D Faupel, P P Meyrueis, Eds., SPIE: Bellingham, WA, 2004, to appear]. Namely, an automatic classifier was developed, which relies on morphological descriptors. Epifluorescence images of cytoskeletal microtubules were processed by Fourier analysis (“spectrum enhancement”), fractal analysis (mass and contour) and spatial differentiation aimed at extracting morphological descriptors. The classifier was successfully applied to rank the structural damage and re-organisation of microtubules. This work focusses on the automatic training of the classifier by a two-layer hierarchical scheme. On the first layer the parameters which control the extraction of the Fourier descriptors are chosen according to some optimality condition (either by solving a saddle point problem or maximising specificity and selectivity); reduction of the Fourier descriptors is obtained by selecting the first few principal components. The latter are passed on to the second layer and merged with descriptors from fractal analysis and spatial differentiation. As a consequence, classification improves. Internal and external (by linear discriminant analysis) validation results will also be presented. The scheme is being applied to images of microtubules and microfilaments from different toxicological experiments.

Diss. (sammanfattning) Umeå : Umeå universitet, 1980 härtill 4 uppsatser, digitalisering@umu

Diss. (sammanfattning) Umeå : Umeå universitet, 1980 härtill 4 uppsatser, digitalisering@umu

Diss. (sammanfattning) Umeå : Umeå universitet, 1980 härtill 4 uppsatser, digitalisering@umu

Diss. (sammanfattning) Umeå : Umeå universitet, 1980 härtill 4 uppsatser, digitalisering@umu