Relative Probability Of Occurrence Research Articles

Binary arithmetic coding with key-based interval splitting

Binary arithmetic coding involves recursive partitioning the range [0,1) in accordance with the relative probabilities of occurrence of the two input symbols. We describe a modification of this approach in which the overall length within the range [0,1) allocated to each symbol is preserved, but the traditional assumption that a single contiguous interval is used for each symbol is removed. A key known to both the encoder and decoder is used to describe where the intervals are "split" prior to encoding each new symbol. The repeated splitting has the effect of both scrambling the intervals and altering their lengths, thereby allowing both encryption and compression to be obtained simultaneously.

Modelling risks in supply chains using Petri net approach

In supply chains, risk analysis involves the process of identifying threats and system vulnerabilities to determine consequences and estimate the expected loss. To analyse any risk environment, it is vital to know the paths of threat and the probability associated with each. Therefore, a complete structure and inference engine are required to determine the most probable path and the relative probabilities of occurrence for any chain of events. Petri Nets (PNs) are considered best to model the discrete event system. This paper introduces a novel approach that uses PNs to model the discrete event behaviour of supply chains and incorporates the max–min inferencing method used in fuzzy reasoning to incorporate the subjective probabilities of events associated with the supply chain process. The proposed approach generates its model based on matrices and performs inferencing automatically. The proposed model uses subjective probability thresholds based on military (MIL) standards and can derive risk analysis results under a changing environment.

The investigation of the secondary structures of various peptide sequences of [formula omitted]-casein by the multicanonical simulation method

The structural properties of Arginine-Glutamic acid-Leucine-Glutamic acid-Glutamic acid-Leucine-Asparagine-Valine-Proline-Glycine (RELEELNVPG, in one letter code), Glutamic acid-Glutamic acid-Glutamine-Glutamine-Glutamine-Threonine-Glutamic acid (EEQQQTE) and Glutamic acid-Aspartic acid-Glutamic acid-Leucine-Glutamine-Aspartic acid-Lysine-Isoleucine (EDELQDKI) peptide sequences of β -casein were studied by three-dimensional molecular modeling. In this work, the three-dimensional conformations of each peptide from their primary sequences were obtained by multicanonical simulations. With using major advantage of this simulation technique, Ramachandran plots were prepared and analysed to predict the relative occurrence probabilities of β -turn, γ -turn and helical structures. Structural predictions of these sequences of β -casein molecule indicate the presence of high level of helical structures and β III-turns. The occurrence probabilities of inverse and classical β -turns were low. The probability of helical structure of each sequence significantly decreased when the temperature increased. Our results show these peptides have highly helical structure and better agreement with the results of spectroscopic techniques and other prediction methods.

Damage spreading in two-dimensional trivalent cellular structures with competing Glauber and Kawasaki dynamics

The damage spreading of the Ising model on several two-dimensional trivalent structures, including soap froth, Voronoi, and hierarchical structures, are studied with competing Glauber and Kawasaki dynamics. The damage spreading transition temperature T(d) and the Curie temperature T(C) of these structures are compared. We find that T(d) of the hierarchical lattices decreases sharply as the probability of occurrence of Kawasaki dynamics increases, whereas for soap froth and Voronoi, T(d) for the Voronoi and soap froth remain nearly unchanged except when the dynamics is dominated by Kawasaki dynamics. T(d) and T(C) in our two-dimensional structures are nearly the same and they behave similarly as we change the relative probability of occurrence of the Glauber and Kawasaki dynamics. A heuristic argument is provided to explain the numerical results.

Using satellite radiotelemetry data to delineate and manage wildlife populations

The greatest promise of radiotelemetry always has been a better understanding of animal movements. Telemetry has helped us know when animals are active, how active they are, how far and how fast they move, the geographic areas they occupy, and whether individuals vary in these traits. Unfortunately, the inability to estimate the error in animals' utilization distributions (UDs), has prevented probabilistic linkage of movements data, which are always retrospective, with future management actions. We used the example of the harvested population of polar bears (Ursus maritimus) in the Southern Beaufort Sea to illustrate a method that provides that linkage. We employed a 2-dimensional Gaussian kernel density estimator to smooth and scale frequencies of polar bear radio locations within cells of a grid overlying our study area. True 2-dimensional smoothing allowed us to create accurate descriptions of the UDs of individuals and groups of bears. We used a new method of clustering, based upon the relative use collared bears made of each cell in our grid, to assign individual animals to populations. We applied the fast Fourier transform to make bootstrapped estimates of the error in UDs computationally feasible. Clustering and kernel smoothing identified 3 populations of polar bears in the region between Wrangel Island, Russia, and Banks Island, Canada. The relative probability of occurrence of animals from each population varied significantly among grid cells distributed across the study area. We displayed occurrence probabilities as contour maps wherein each contour line corresponded with a change in relative probability. Only at the edges of our study area and in some offshore regions were bootstrapped estimates of error in occurrence probabilities too high to allow prediction. Error estimates, which also were displayed as contours, allowed us to show that occurrence probabilities did not vary by season. Near Barrow, Alaska, 50% of bears observed are predicted to be from the Chukchi Sea population and 50% from the Southern Beaufort Sea population. At Tuktoyaktuk, Northwest Territories, Canada, 50% are from the Southern Beaufort Sea and 50% from the Northern Beaufort Sea population. The methods described here will aid managers of all wildlife that can be studied by telemetry to allocate harvests and other human perturbations to the appropriate populations, make risk assessments, and predict impacts of human activities. They will aid researchers by providing the refined descriptions of study populations that are necessary for population estimation and other investigative tasks.

A quantitative approach to conservation planning: using resource selection functions to map the distribution of mountain caribou at multiple spatial scales

Summary Visualizing the distribution of rare or threatened species is necessary for effective implementation of conservation initiatives. Generalized linear models and geographical information systems (GIS) are now powerful tools for conservation planning, but issues of data availability, scale and model extrapolation complicate some applications. Mountain caribou are an endangered ecotype of woodland caribou Rangifer tarandus caribou that occurs across central and southern British Columbia, Canada. Currently, conservation professionals use coarse small‐scale maps of important habitats to manage forest harvesting and human access across the northern extent of mountain caribou range. These maps were produced before the advent of readily available digital spatial information and are based on expert opinion and limited empirical data. With the purpose of refining existing maps, we used survey results, radio‐telemetry locations and GIS data to construct resource selection functions (RSF) that quantified the habitat affinities and predicted the relative probability of occurrence of mountain caribou at two spatial scales. At the scale of the patch, the most parsimonious RSF model consisted of covariates for vegetation and aptly predicted the occurrence of caribou across low‐ to mid‐elevation habitats, but performed poorly across steep alpine terrain. At the landscape scale, a model containing Gaussian terms for elevation and slope was effective at predicting the broader distribution of caribou. We produced a map consisting of the product of the relative probabilities of the patch and landscape RSF. The final map represented the relative probability of occurrence of caribou in vegetative patches weighted by the relative probability of occurrence across the larger study area. We found strong agreement between current definitions of important caribou habitats developed from expert opinion and RSF‐based maps generated from empirical data. Synthesis and applications. Both expert opinion and RSF‐based approaches offer unique advantages for conservation mapping. Interpretability of results, documentation and repeatability of methods and data, estimates of precision and costs should all be considered when evaluating a technique. We argue that for some species and geographical locations, RSF is a superior technique, but expert opinion should play a role in model development and interpretation.

Molecular modeling of various peptide sequences of gliadins and low‐molecular‐weight glutenin subunits

The contribution of the three-dimensional structures of one heptapeptide (PQPQPFP) sequence and one pentapeptide (PQQPY) repeat sequence of alpha/beta-gliadins, one heptapeptide (PQQPFPQ) repeat sequence of gamma-gliadins, two heptapeptide (PQQPPFS and QQQQPVL) repeat motifs of low-molecular-weight (LMW) subunits and a tetrapeptide sequence in polyQ region of S-rich prolamins to their conformations are investigated by using the recently developed multicanonical simulation procedure. Ramachandran plots were prepared and analysed to predict the relative occurrence probabilities of gamma-tutn, gamma-turn, and helical structures. The probability of inverse 7-turn was generally higher than that of beta-turns in all sequences investigated. Occurrence probability of helical structure in the repetitive domain of gliadins was low. Structural predictions of QQQQPVL sequence of LMW-glutenin subunits and QQQQ sequence in the polyQ region of S-rich prolamins indicate the presence of helical structures with the probability of >20%. The probability of helical structure significantly decreased around 100 degrees C.

A 9‐year summary of radar characteristics of mesocyclonic storms and of deep convection in southern Québec

Nine summers of reflectivity and Doppler data, (1993–2001), archived by the Marshall Radar Observatory of McGill University have been processed for the purpose of identifying the location, strength and frequency of occurrence of severe weather events associated with convective activity. A mesocyclone detection and tracking algorithm has identified 329 features with a lifetime of at least 10 minutes. The distribution of their duration, path length, diameter, depth, rotational velocity and shear are provided, as well as their hourly and monthly frequency. Their geographical distribution reveals an increased relative probability of occurrence over the western area of the McGill radar coverage as well as to the north, near Mirabel, and a reduced probability of occurrence near the metropolitan area of Montréal. The analysis of deep convection has been performed in terms of upper level Vertically Integrated Liquid water content maps (UVIL) where the vertical integration of reflectivity begins at a height of 5 km. UVIL maps are preferred among other types of reflectivity‐based radar products because they are the least affected by radar artefacts such as bright band, ground echoes, anomalous propagation and beam blocking. An inherent bias, present in the standard generation of UVIL maps, and due to an oxygen attenuation overcorrection and to the vertical profile of reflectivity of thunderstorms as sampled by a broadening beamwidth, has been identified and corrected. The geographical distribution of UVIL measurements in terms of the time that a UVIL threshold of 10 and 15 kg m−2 is exceeded has been obtained for both the individual years and for the entire 9‐year period. Areas of preferred convection have been identified in the latter, particularly along the flatlands of the St. Lawrence River Basin. A relative minimum is quite noticeable along a broad corridor running north and south of the radar over heavily forested mountainous regions. This combination results in a non‐negligible correlation of the order of ‐0.2 between the height of the topography (m) and deep convection. Curves revealing the relative severity of the nine years in terms of a continuous UVIL threshold have also been derived. The years 1994, 1998 and 1999 emerged as the most active years while 1996 and 2000 were clearly very quiet.

Influences of roads and development on bird communities in

Our objective was to improve knowledge about effects of broad-scale road and development variables on bird communities in protected desert landscapes. Bird species richness and the relative abundance or probability of occurrence of many species were significantly associated with total length of roads within each of two spatial extents (1- and 2-km radii), distance to the nearest road, distance to the nearest development, or the two-way interactions of these variables. Regression models reflected non-linear relations, interaction effects, spatial-extent effects, and interannual variation. Road and development effects warrant special attention in protected areas because such places may be important sources of indigenous bird communities in a region.

Development and testing of phenologically driven grizzly bear habitat models

We developed and compared three habitat models for estimating the relative probability of occurrence, by month, for grizzly bears (Ursus arctos) in Jasper National Park (JNP), Alberta. These models included 1) a habitat map derived from remote sensing Landsat imagery; 2) food-index models generated from the predicted occurrence of bear foods and assigned monthly importance values; and 3) probabilistic food models representing the occurrence of each bear food. Resource selection function (RSF) models for grizzly bears were generated using 3,924 global positioning system (GPS) radiotelemetry locations and the above habitat models. Comparisons were made among RSF models, by month, using Akaike’s Information Criterion (AIC). In all seven months (April to October), food-index models performed poorly. In April and July, the remote-sensing habitat map predicted bears best, while the food-probability models performed best in the remaining five months. Overall, we found substantial improvement by using food-probability models for predicting JNP grizzly bear occurrence. Remote-sensing maps, although predictive, may not reveal underlying mechanisms and fail to recognize the dynamic nature of seasonal grizzly bear habitats. The disconnect between food-index and food-probability models suggests that monthly food importance values require additional parameterization. Development of spatial food models on phenologically important scales more closely matches the resources and temporal scales at which animals perceive and use resources.

Dependence of the peptide amide III vibration on the phi dihedral angle.

Dependence of the peptide amide III vibration on the phi dihedral angle.

GIS and ANN model for landslide susceptibility mapping

Landslide hazard is as the probability of occurrence of a potentially damaging landslide phenomenon within specified period of time and within a given area. The susceptibility map provides the relative spatial probability of landslides occurrence. A study is presented of the application of GIS and artificial neural network model to landslide susceptibility mapping, with particular reference to landslides on natural terrain in this paper. The method has been applied to Lantau Island, the largest outlying island within the territory of Hong Kong. A three-level neural network model was constructed and trained by the back-propagate algorithm in the geographical database of the study area. The data in the database includes digital elevation modal and its derivatives, landslides distribution and their attributes, superficial geological maps, vegetation cover, the raingauges distribution and their 14 years 5-minute observation. Based on field inspection and analysis of correlation between terrain variables and landslides frequency, lithology, vegetation cover, slope gradient, slope aspect, slope curvature, elevation, the characteristic value, the rainstorms corresponding to the landslide, and distance to drainage Une are considered to be related to landslide susceptibility in this study. The artificial neural network is then coupled with the ArcView3.2 GIS software to produce the landslide susceptibility map, which classifies the susceptibility into three levels: low, moderate, and high. The results from this study indicate that GIS coupled with artificial neural network model is a flexible and powerful approach to identify the spatial probability of hazards.

MOLECULAR MODELING OF TWO HEXAPEPTIDE REPEAT MOTIFS OF HMW GLUTENIN SUBUNITS

The three-dimensional structures of two hexapeptide repeat motifs (PGQGQQ and SGQGQQ, in one letter code) in the repetitive central domain of HMW glutenin subunits are investigated by using the multicanonical simulation procedure. Ramachandran plots were prepared and analyzed to predict the relative occurrence probabilities of β-turn and γ-turn structures and helical state. Structural predictions of PGQGQQ repeat motif indicated the presence of high level of β-turns and considerable level of γ-turns. Simulations of the repeat motifs in the repetitive central domain of HMW glutenin subunits indicated that these structures take important part in the three-dimensional structures of repeat motifs.

MULTICANONICAL SIMULATIONS OF FIVE TETRAPEPTIDE SEQUENCES IN THE CENTRAL DOMAIN OF HMW GLUTENIN

The application of the multicanonical simulation method to small proteins and peptides seems to be feasible and should be undertaken. In this work, the three-dimensional structures of five common tetrapeptide sequences (QPGQ, QSGQ, YPTS, SPQQ and QPGY, in one letter code) in the repetitive central domain of HMW glutenin subunits are investigated by using the multicanonical simulation procedure. Ramachandran plots were prepared and analyzed to predict the relative occurrence probabilities of β-turn and γ-turn structures and helical states. Structural predictions of the five tetrapeptide sequences indicated the presence of high level of β-turns and considerable level of γ-turns. It was also possible to distinguish different type of turns and their occurrence probabilities.

Econophysics: Can physicists contribute to the science of economics?

Econophysics is a new word, used to describe work being done by physicists in which financial and economic systems are treated as complex systems. Everyone is affected by economic fluctuations, and quantifying fluctuations is a topic that many physicists have contributed to in recent years. Moreover, everyone – rich and poor – would be powerfully affected by a breakdown of the world-wide financial system. Further, it is possible that methods and concepts developed in the study of strongly fluctuation systems might yield new results in economics. Finally, economic systems are complex interacting systems for which a tremendous amount of quantitative data exists, much of it never analyzed. Here we discuss selected recent examples where statistical physicists studying fluctuations have uncovered two new empirical “laws”. The first empirical law concerns the histogram giving the relative occurrence probability that a stock experiences a given price change; this histogram decreases as the given price change increases, with an apparent power law tail that describes fluctuations differing by as much as 8 orders of magnitude in this relative occurrence probability. The second empirical law concerns a histogram of size changes of business firms, which has a width that decreases as a power law of the firm size for firms that range over roughly 8 orders of magnitude. In addition to such scaling laws, there appears also the analog of “universality” – e.g., the analogous histogram of country size appears to obey the same scaling law, with the same exponent, as the histogram of firm size.

Importance Analysis of the Fundamental Events to the Top Event in a Fault Tree by Fuzzy Pairwise Comparison Method.

FTA (Fault Tree Analysis) is used for reliability and safaty analysis of system. In FTA, the critical importance of each fundamental event is defined in order to control occurrence of top event effectively. To calculate critical importance, it is necessary to get occurrence probability of allfundamental events. However, it is hard to get these probabilities. Therefore, it has bees proposed to estimate relative occurrence probabilities of all fundamental events by pairwise comparison method with eigenvector. In this paper, we have proposed a method for estimating subjectively critical importance by fuzzy pairwise comparison method. Furthermore, this method is applied to safety analysis of a bucket elevator. Consequently, the priority of action required to fundamental events contained in the fault tree has become dear.

What is an 'intact' hymen? A critique of the literature.

The purpose of this study was to establish medico-legal guidelines based upon medical findings which support or refute allegations of sexual penetration, taking into account non-sexual explanations for positive physical findings. A review of the literature was undertaken to examine what has been determined about the range of usual findings which can be expected if the hymen has been penetrated. While a large body of literature is available on the topic, some findings are ambiguous, and further research is required to advance and clarify our knowledge base in these areas. In only a minority of non-acute cases can definitive statements be made as to whether an alleged molestation has occurred. A non-scarred hymen that will not admit a finger is 'intact'; a hymenal opening accommodating two fingers or a vaginal speculum, with evidence of a deficit or scarring at the lower pole, indicates past sexual or, possibly, non-sexual penetration. Other findings are not definitive and, at best, can estimate only relative probability of occurrence of penetration. Findings within the normal range should be presented as 'neither confirm nor deny abuse', not 'consistent with abuse'. Often, it is impossible to establish whether a hymen is 'intact' in regard to past sexual intercourse.

Formal scientific research of traffic collision data utilizing GIS

This paper explores the tenuous link between speeding behavior and accident causation, one that has not been well established in the international literature to date. Taking advantage of established engineering conventions and formulae, we were able to set up an a priori hypothesis suitable for testing. Utilizing this formal scientific method (which GIS researchers have been criticised for not using) we establish a statistical link for this relationship. Our methodology can be used to support all police intervention strategies, including the controversial photo radar systems. The results from our research have been entered into a GIS in order to create a map for spatial display. This map illustrates the relative probability or risk of collision occurrence resulting from speeding at all intersections and interchanges within the scope of the study. It is suggested that this methodology could easily be maintained with periodic updates of data, thus creating a dynamic model from which to monitor traffic safety within the city. Furthermore, this model can be utilized to study specific strategies, allowing for the scrutiny of before, during and after effects. The study area is the entire city of Calgary, Alberta, Canada, and includes all traffic collisions occurring during the year of 1994.

Local calcium transients triggered by single L-type calcium channel currents in cardiac cells

Excitation-contraction coupling was studied in mammalian cardiac cells in which the opening probability of L-type calcium (Ca2+) channels was reduced. Confocal microscopy during voltage-clamp depolarization revealed distinct local transients in the concentration of intracellular calcium ions ([Ca2+]i). When voltage was varied, the latency to occurrence and the relative probability of occurrence of local [Ca2+]i transients varied as predicted if Ca2+ release from the sarcoplasmic reticulum (SR) was linked tightly to Ca2+ flux through L-type Ca2+ channels but not to that through the Na-Ca exchanger or to average [Ca2+]i. Voltage had no effect on the amplitude of local [Ca2+]i transients. Thus, the most efficacious "Ca2+ signal" for activating Ca2+ release from the SR may be a transient microdomain of high [Ca2+]i beneath an individual, open L-type Ca2+ channel.

Preferred structures in small particles

Abstract Morphological transformations of Au particles supported on SiO were observed by real-time high-resolution electron microscopy, and the data were analysed quantitatively to extract the relative probabilities of the different morphologies and compared with a probability model to understand the role of the different parameters that affect the transformations. The experimental data and probability model show good agreement and reveal several interesting trends for the first time. The single crystal population dominates over the icosahedral multiply twinned particles (Ic) and the decahedral multiply twinned particles (Dc) over the observed size regime 2–8nm. The Ic shows a maximum in relative probability of occurrence at smaller sizes, whereas the Dc probability increases with size, leading to a transition region centred at 6·5 nm particle diameter at which Dc and Ic show almost equal relative probabilities. The activation energies of the morphologies are also affected by the surface stress and anisotropy of the surface free energies.