1,479 research outputs found
Asymptotic results with generalized estimating equations for longitudinal data
We consider the marginal models of Liang and Zeger [Biometrika 73 (1986)
13-22] for the analysis of longitudinal data and we develop a theory of
statistical inference for such models. We prove the existence, weak consistency
and asymptotic normality of a sequence of estimators defined as roots of
pseudo-likelihood equations.Comment: Published at http://dx.doi.org/10.1214/009053604000001255 in the
Annals of Statistics (http://www.imstat.org/aos/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Reconstruction of Bandlimited Functions from Unsigned Samples
We consider the recovery of real-valued bandlimited functions from the
absolute values of their samples, possibly spaced nonuniformly. We show that
such a reconstruction is always possible if the function is sampled at more
than twice its Nyquist rate, and may not necessarily be possible if the samples
are taken at less than twice the Nyquist rate. In the case of uniform samples,
we also describe an FFT-based algorithm to perform the reconstruction. We prove
that it converges exponentially rapidly in the number of samples used and
examine its numerical behavior on some test cases
Asymptotic Results with Generalized Estimating Equations for Longitudinal data II
We consider the marginal models of Liang and Zeger (1986) for the analysis of longitudinal data and we develop a theory of statistical inference for such models. We prove the existence, weak consistency and asymptotic normality of a sequence of estimators defined as roots of pseudo-likelihood equations.Generalized estimating equations, Generalized linear model, Consistency, Asymptotic normality
The Indian oil sardine
The Indian oil sardine, Sardinella longiceps Val. sustains one of the major pelagic fisheries of the country.Though the fish occurs all along the peninsular region in varying quantities, the highest abundance has been noticed off the Kerala and Karnataka coasts, especially between Alleppey and Karwar. During the decade from 1969 to 1978, the highest all India oil sardine catch, was made
in 1970. From the existing catch trends it is indicated that the sardine catches during the 1980 season
would not be far from the average of the last decade. In the light of the stock assessment studies it may be
mentioned that increase in fishing effort would result in better catches
Newinsights in the ontogeny and taphonomy of the Devonian acanthodian Triazeugacanthus affinis from the Miguasha Fossil-Lagerstatte, Eastern Canada
Progressive biomineralization of a skeleton occurs during ontogeny in most animals. In fishes, larvae are poorly mineralized, whereas juveniles and adults display a progressively more biomineralized skeleton. Fossil remains primarily consist of adult specimens because the fossilization of poorly-mineralized larvae and juveniles necessitates exceptional conditions. The Miguasha Fossil-Lagerstatte is renowned for its Late Devonian vertebrate fauna, revealing the exceptional preservation of fossilized ontogenies for 14 of the 20 fish species from this locality. The mineralization of anatomical structures of the acanthodian Triazeugacanthus affinis from Miguasha are compared among larval, juvenile and adult specimens using Energy Dispersive X-ray Spectrometry. Chemical composition of anatomical structures of Triazeugacanthus reveals differences between cartilage and bone. Although the histology and anatomy is well-preserved, Fourier transform infrared spectrometry shows that the original chemical composition of bone is altered by diagenesis; the mineral phase of the bone (i.e., hydroxyapatite) is modified chemically to form more stable carbonate-fluorapatite. Fluorination occurring in mineralized skeletal structures of adult Triazeugacanthus is indicative of exchanges between groundwater and skeleton at burial, whereas the preservation of larval soft tissues is likely owing to a rapid burial under anoxic conditions. The exceptional state of preservation of a fossilized ontogeny allowed us to characterize chemically the progressive mineralization of the skeleton in a Devonian early vertebrate
Crystallization, data collection and data processing of maltose-binding protein (MalE) from the phytopathogen Xanthomonas axonopodis pv. citri
Maltose-binding protein is the periplasmic component of the ABC transporter
responsible for the uptake of maltose/maltodextrins. The Xanthomonas axonopodis
pv. citri maltose-binding protein MalE has been crystallized at 293 Kusing
the hanging-drop vapour-diffusion method. The crystal belonged to the
primitive hexagonal space group P6_122, with unit-cell parameters a = 123.59,
b = 123.59, c = 304.20 Å, and contained two molecules in the asymetric unit. It
diffracted to 2.24 Å resolution
Detection and classification of buried dielectric anomalies by means of the bispectrum method and neural networks
Includes bibliographical references.The development of neural network-based system for detection and classification of buried landmines is the main focus of this paper. Shape-dependent features are extracted by means of the bispectrum method. These features are then applied to the neural network. A multilayer back-propagation-type neural network is trained and tested on the feature sets extracted from equally spaced radial slices of image windows. Simulation results obtained for two types of targets indicated good detection and classification rates
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