87,183 research outputs found
Approximate Discrete Probability Distribution Representation using a Multi-ResolutionBinary Tree
Computing and storing probabilities is a hard problem as soon as one has to deal with complex distributions over multiples random variables. The problem of efficient representation of probability distributions is central in term of computational efficiency in the field of probabilistic reasoning. The main problem arises when dealing with joint probability distributions over a set of random variables: they are always represented using huge probability arrays. In this paper, a new method based on a binary-tree representation
is introduced in order to store efficiently very large joint distributions. Our approach approximates any multidimensional joint distributions using an adaptive discretization of the space. We make the assumption that the lower is the probability mass of a particular region of feature space, the larger is the discretization step. This assumption leads to a very optimized representation in term of time and memory. The other advantages of our approach are the ability to refine dynamically the distribution every time it is needed leading to a more accurate representation of the probability
distribution and to an anytime representation of the distribution
Amino Acids Sequences Analysis on Collagen
Staring from available information about amino acids properties and sequences on collagen type I chains, the aims of the study were to identify the principal property component and to analyze the similarities within and between collagens on five species. The principal component analysis applied on twentyfour amino acids properties revealed that the hydrophobic or hydrophilic character measured by Wealling et al. is more stable comparing with the other investigated properties. Similarity analysis identified similar and dissimilar within and between studied species from the viewpoint of amino acids sequences on collagen type I alpha 1 and 2 chains
Anxiety and Posttraumatic Stress Disorder in the Context of Human Brain Evolution:A Role for Theory in DSM-V?
The “hypervigilance, escape, struggle, tonic immobility”\ud
evolutionarily hardwired acute peritraumatic response\ud
sequence is important for clinicians to understand. Our\ud
commentary supplements the useful article on human\ud
tonic immobility (TI) by Marx, Forsyth, Gallup, Fusé and Lexington (2008). A hallmark sign of TI is peritraumatic\ud
tachycardia, which others have documented as a\ud
major risk factor for subsequent posttraumatic stress\ud
disorder (PTSD). TI is evolutionarily highly conserved\ud
(uniform across species) and underscores the need for\ud
DSM-V planners to consider the inclusion of evolution\ud
theory in the reconceptualization of anxiety and PTSD.\ud
We discuss the relevance of evolution theory to the\ud
DSM-V reconceptualization of acute dissociativeconversion\ud
symptoms and of epidemic sociogenic disorder(epidemic “hysteria”). Both are especially in need of attention in light of the increasing threat of terrorism\ud
against civilians. We provide other pertinent examples.\ud
Finally, evolution theory is not ideology driven (and\ud
makes testable predictions regarding etiology in “both\ud
directions”). For instance, it predicted the unexpected\ud
finding that some disorders conceptualized in DSM-IV-TR as innate phobias are conditioned responses and thus better conceptualized as mild forms of PTSD. Evolution\ud
theory may offer a conceptual framework in\ud
DSM-V both for treatment and for research on psychopathology.\u
Consistency of Skinner Box Activity Measures in the domestic Rabbit (Oryctolagus cuniculus)
Consistency of individual differences in several measures of Skinner box operant and other activity and their intercorrelations in 14 chinchilla bred rabbits were studied. Reliability analysis revealed that both operant and activity measures were highly consistent (Cronbach alpha>0.87) over at least 15 days. Furthermore, locomotor activity, the tendencies to press the lever with high frequency, to make many errors, to check the presence of food in the dispenser as well as rearing were highly inter-correlated, making up a single dimension of activity. However, grooming did not correlate with these behaviors
Cultural vs. Economic Investments of Tribal Casinos in Historical Perspective
This presentation will elaborate how tribal community leaders originally envisioned utilizing gaming revenues to fund cultural investments such as language retention or elders’ programs, and whether they and their fellow community members assigned cultural investments a greater value than economic investments (e.g., infrastructure such as paved roads). Preliminary research suggests that leaders seeking casino or gaming site construction commonly identified cultural investments as an essential element of community development initiatives, and that they could be considered unique from and complementary to economic development initiatives. These and similar acts openly challenged the desires of state officials and national policy makers, who envisioned gaming revenues being utilized almost exclusively for economic development. Why is this line of investigation noteworthy? Notwithstanding the wealth of literature that has been produced in the last two decades confirming improved reservation infrastructure, among other issues, limited time and energy has been directed toward exploring the extent and scope of cultural investments; or elaborating why communities considered economically “poor” persevere (in certain cases) in privileging cultural investments over what outsiders and oftentimes reservation community members would characterize as critical infrastructure projects
Experimental Combat-Stress Model in Rats: Histological Examination of Effects of Amelogenesis-A Possible Measure of Diminished Vagal Tone Episodes
Developmental defects of enamel-stress histomarker rings (accentuated striae) may be a potential measure of diminished vagal tone in research on extreme stress such as exposure to combat. To develop an animal model of this measure, we examined the enamel of rat incisors which erupt continuously. We examined incisors from 15 stressed-colony rats and 7 control-rats for these histomarkers using the Visible Burrow System (VBS). VBS was developed to study combat stress in rats. No stress rings were found in any of the rat incisors examined. In contrast to humans, rats have likely evolved to prioritize incisor strength during combat stress. Studies of amelogenesis during combat stress in other rodents with continuously growing incisors are warranted. Laboratory animals such as rabbits or marmosets may be especially suitable, since they less frequently use their incisors for self defense
Name Strategy: Its Existence and Implications
It is argued that colour name strategy, object name strategy, and chunking strategy in memory are all aspects of the same general phenomena, called stereotyping, and this in turn is an example of a know-how representation. Such representations are argued to have their origin in a principle called the minimum duplication of resources. For most the subsequent discussions existence of colour name strategy suffices. It is pointed out that the Berlin†- Kay†universal partial ordering of colours and the frequency of traffic accidents classified by colour are surprisingly similar; a detailed analysis is not carried out as the specific colours recorded are not identical. Some consequences of the existence of a name strategy for the philosophy of language and mathematics are discussed: specifically it is argued that in accounts of truth and meaning it is necessary throughout to use real numbers as opposed to bi-valent quantities; and also that the concomitant label associated with sentences should not be of unconditional truth, but rather several real-valued quantities associated with visual communication. The implication of real-valued truth quantities is that the Continuum Hypothesis of pure mathematics is side-stepped, because real valued quantities occur ab initio. The existence of name strategy shows that thought/sememes and talk/phonemes can be separate, and this vindicates the assumption of thought occurring before talk used in psycho-linguistic speech production models.
National Trends on Agricultural Crops Production: Cluster Analysis
Staring from descriptive data on crop production and cultivated area at national level during on fifteen years, the aim of this study is to reveal the trends on crops cultivation. The cluster analysis reveals linkages between crops classes as well as between different crops, which can be partly assigned to crops rotation. Time series analysis reveals dramatically reducing of production of some crops, such as flax, hemp, and sugar beet, and increasing of production, such at sunflower, and increasing of productivity, such at potatoes and field vegetables
A participatory methodology for large scale field trials in the UK
Farmer participation was essential in developing a uniquely useful set of wheat variety trials data on a wide range of organic farms over two years. Although the trials were successful, it became clear that some of the participating farmers felt there were some limitations in the process. These included a lack of ownership in the project and a concern for more researcher help. It was clear that a greater time in-vestment was needed at the start of the project to help with farmer understanding and ownership. De-spite the negative comments, farmers appreciated their involvement, particularly in contrasting their own views and information with that from the wider scene. Farmer participation is essential for systems-level research and this project helped to develop a small core of trained farmers and researchers
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