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Statistical Confidence (statistical + confidence)
Selected AbstractsStatistical confidence in parentage analysis with incomplete sampling: how many loci and offspring are needed?MOLECULAR ECOLOGY, Issue 5 2000B. D. Neff Abstract We have recently presented models to estimate parentage in breeding systems with multiple mating and incomplete sampling of the candidate parents. Here we provide formulas to calculate the statistical confidence and the optimal trade-off between the number of loci and offspring. These calculations allow an understanding of the statistical significance of the parentage estimates as well as the appropriate sampling regime required to obtain a desired level of confidence. We show that the trade-off generally depends on the parentage of the putative parents. When parentage is low, sampling effort should concentrate on increasing the number of loci. Otherwise, there are similar benefits from increasing the number of loci or offspring. We demonstrate these methods using genetic data from a nest of the bluegill sunfish (Lepomis macrochirus). [source] Analytical modelling of users' behaviour and performance metrics in key distribution schemesEUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 1 2010Massimo Tornatore Access control for group communications must ensure that only legitimate users can access the authorised data streams. This could be done by distributing an encrypting key to each member of the group to be secured. To achieve a high level of security, the group key should be changed every time a user joins or leaves the group, so that a former group member has no access to current communications and a new member has no access to previous communications. Since group memberships could be very dynamic, the group key should be changed frequently. So far, different schemes for efficient key distribution have been proposed to limit the key-distribution overhead. In previous works, the performance comparison among these different schemes have been based on simulative experiments, where users join and leave secure groups according to a basic statistical model of users' behaviour. In this paper, we propose a new statistical model to account for the behaviour of users and compare it to the modelling approach so far adopted in the literature. Our new model is able to to lead the system to a steady state (allowing a superior statistical confidence of the results), as opposed to current models in which the system is permanently in a transient and diverging state. We also provide analytical formulations of the main performance metrics usually adopted to evaluate key distribution systems, such as rekey overheads and storage overheads. Then, we validate our simulative outcomes with results obtained by analytical formulations. Copyright © 2009 John Wiley & Sons, Ltd. [source] Statistical confidence in parentage analysis with incomplete sampling: how many loci and offspring are needed?MOLECULAR ECOLOGY, Issue 5 2000B. D. Neff Abstract We have recently presented models to estimate parentage in breeding systems with multiple mating and incomplete sampling of the candidate parents. Here we provide formulas to calculate the statistical confidence and the optimal trade-off between the number of loci and offspring. These calculations allow an understanding of the statistical significance of the parentage estimates as well as the appropriate sampling regime required to obtain a desired level of confidence. We show that the trade-off generally depends on the parentage of the putative parents. When parentage is low, sampling effort should concentrate on increasing the number of loci. Otherwise, there are similar benefits from increasing the number of loci or offspring. We demonstrate these methods using genetic data from a nest of the bluegill sunfish (Lepomis macrochirus). [source] Identification of shed proteins from chinese hamster ovary cells: Application of statistical confidence using human and mouse protein databasesPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 7 2005Mamoun Ahram Abstract The shedding process releases ligands, receptors, and other proteins from the surface of the cell and is a mechanism whereby cells communicate. Even though altered regulation of this process has been implicated in several diseases, global approaches to evaluate shed proteins have not been developed. A goal of this study was to identify global changes in shed proteins in media taken from cells exposed to low-doses of radiation to develop a fundamental understanding of the bystander response. Chinese hamster ovary cells were chosen because they have been widely used for radiation studies and are reported to respond to radiation by releasing factors into the media that cause genomic instability and cytotoxicity in unexposed cells, i.e., a bystander effect. Media samples taken for irradiated cells were evaluated using a combination of tandem- and Fourier transform-ion cyclotron resonance (FT-ICR)-mass spectrometry (MS) analyses. Since the hamster genome has not been sequenced, MS data was searched against the mouse and human protein databases. Nearly 150 proteins identified by tandem mass spectrometry were confirmed by FT-ICR. When both types of MS data were evaluated, using a new confidence scoring tool based on discriminant analyses, about 500 proteins were identified. Approximately 20% of these identifications were either integral membrane proteins or membrane associated proteins, suggesting that they were derived from the cell surface and, hence were likely shed. However, estimates of quantitative changes, based on two independent MS approaches, did not identify any protein abundance changes attributable to the bystander effect. Results from this study demonstrate the feasibility of global evaluation of shed proteins using MS in conjunction with cross-species protein databases and that significant improvement in peptide/protein identifications is provided by the confidence scoring tool. [source] Fluorescence correlation spectroscopy for the detection and study of single molecules in biologyBIOESSAYS, Issue 8 2002Miguel Ángel Medina The recent development of single molecule detection techniques has opened new horizons for the study of individual macromolecules under physiological conditions. Conformational subpopulations, internal dynamics and activity of single biomolecules, parameters that have so far been hidden in large ensemble averages, are now being unveiled. Herein, we review a particular attractive solution-based single molecule technique, fluorescence correlation spectroscopy (FCS). This time-averaging fluctuation analysis which is usually performed in Confocal setups combines maximum sensitivity with high statistical confidence. FCS has proven to be a very versatile and powerful tool for detection and temporal investigation of biomolecules at ultralow concentrations on surfaces, in solution, and in living cells. The introduction of dual-color cross-correlation and two-photon excitation in FCS experiments is currently increasing the number of promising applications of FCS to biological research. BioEssays 24:758,764, 2002. © 2002 Wiley Periodicals, Inc. [source] | ||||||||||