Assignment methods for incidence calculus

Incidence calculus is a mechanism for probabilistic reasoning in which sets of possible worlds, called incidences, are associated with axioms, and probabilities are then associated with these sets. Inference rules are used to deduce bounds on the incidence of formulae which are not axioms, and bounds for the probability of such a formula can then be obtained. In practice an assignment of probabilities directly to axioms may be given, and it is then necessary to find an assignment of incidence which will reproduce these probabilities. We show that this task of assigning incidences can be viewed as a tree searching problem, and two techniques for performing this research are discussed. One of these is a new proposal involving a depth first search, while the other incorporates a random element. A Prolog implementation of these methods has been developed. The two approaches are compared for efficiency and the significance of their results are discussed. Finally we discuss a new proposal for applying techniques from linear programming to incidence calculus.

Hidden Gems: systematically searching electronic databases for research publications for social work and social care.

Context: Electronic bibliographic databases are a key source for professional publications about social work and community care more generally. This article describes and evaluates a method of identifying relevant articles as part of a systematic review of research evidence. Decision making about institutional and home care services for older people is used as an example. Method: Four databases (Social Science Citation Index, Medline, CINAHL, and Caredata) that abstract publications relevant to health and social services were searched systematically to identify relevant research studies. The items retrieved were appraised independently using a standard form developed for the purpose. The searches were compared in terms of sensitivity, precision, overlap between databases, and inter-rater reliability. Results: The search retrieved 525 articles, of which 276 were relevant. The four databases retrieved 55%, 41%, 19%, and 1% of the relevant articles respectively, achieving these sensitivities with precision levels of 54%, 48%, 84% and 94%. The databases retrieved 116, 73, 24 and 15 unique relevant articles respectively, showing the need to use a range of databases. Discussion: A general approach to creating a search to retrieve relevant research has been developed. The development of an international, indexed database dedicated to literature relevant to social services is a priority to enable progress in evidence-based policy and practice in social work. Editors and researchers should consider using structured abstracts in order to improve the retrieval and dissemination of research.

High-precision radiocarbon measurements of contemporaneous tree-ring wood from the British Isles and New Zealand: AD 1850-950.

The University of Waikato, Hamilton, New Zealand and The Queen's University of Belfast, Northern Ireland radiocarbon dating laboratories have undertaken a series of high-precision measurements on decadal samples of dendrochronologically dated oak (Quercus petraea) from Great Britain and cedar (Libocedrus bidwillii) and silver pine (Lagarostrobos colensoi) from New Zealand. The results show an average hemispheric offset over the 900 yr of measurement of 40±13 yr. This value is not constant but varies with a periodicity of about 130 yr. The Northern Hemisphere measurements confirm the validity of the Pearson et al. (1986) calibration dataset.

Searching for the IRA 'disappeared': Ground-penetrating radar investigation of a churchyard burial site, Northern Ireland

A search for the body of a victim of terrorist abduction and murder was made in a graveyard on the periphery of a major conurbation in Northern Ireland. The area is politically sensitive and the case of high profile. This required non-invasive, completely non-destructive and rapid assessment of the scene. A MALA RAMAC ground-penetrating radar system was used to achieve these objectives. Unprocessed and processed 400MHz data shows the presence of a collapse feature above and around a known 1970s burial with no similar collapse above the suspect location. In the saturated, clay-rich sediments of the site, 200MHz data offered no advantage over 400MHz data. Unprocessed 100MHz data shows a series of multiples in the known burial with no similar features in the suspect location. Processed 100MHz lines defined the shape of the collapse around the known burial to 2m depth, together with the geometry of the platform (1m depth) the gravedigger used in the 1970s to construct the site. In addition, processed 100MHz data showed both the dielectric contrast in and internal reflection geometry of the soil imported above the known grave. Thus the sequence, geometry, difference in infill and infill direction of the grave was reconstructed 30 years after burial. The suspect site showed no evidence of shallow or deep inhumation. Subsequently, the missing person������¢���¯���¿���½���¯���¿���½s body was found some distance from this site, vindicating the results and interpretation from ground-penetrating radar. The acquisition, processing, collapse feature and sequence stratigraphic interpretation of the known burial and empty (suspect) burial site may be useful proxies for other, similar investigations. GPR was used to evaluate this site within 3 hours of the survey commencing, using unprocessed data. An additional day of processing established that the suspect body did not reside here, which was counter to police and community intelligence.

Micromorphology of lamellae formed in an alluvial soil, Big Pine Tree Archeological Site, South Carolina

The formation of lamellae in soils is not clearly understood. The objectives of this study are to examine the microscopical characteristics of selected well developed lamellae inorder to identify the major processes involved in their formation at the Big Pine Tree Archaeological site on the Savannah River, South Carolina. Well developed lamellae have formed in a fine sandy alluvial soil that is about 11,000 to 12,000 years old. In the field, these lamellae are observed as 1 to 4.2 cm thick horizontal layers having a smooth upper and a wavy, sometimes irregular, lower boundary with adjacent interlamellae horizons. Soil thin sections reveal denser accumulations of brown fine silt and clay coatings in the upper and lower sections of the lamellae. The center of the lamellae has mainly orange highly oriented discontinuous clay coatings bridging quartz grains and some silt accumulations. Although, horizontal layering of denser areas (accumulations of fine silt and clay coatings) is also observed in the middle of the lamellae. The interlamellae horizons are mainly loose quartz grains. Low total carbon values (

Novel frenatins from the skin of the Australasian Giant White-lipped tree frog, Litoria infrafrenata: cloning of precursor cDNAs and identification in defensive skin secretion.

The Australasian anuran amphibian genus Litoria, contains many phenotypically-diverse species as a result of radial evolution of an ancestral species into different biotopes much in the manner of the indigenous marsupial mammals. In common with members of the Central/South American genus Phyllomedusa, their specialized skin granular glands are factories for the production of a plethora of biologically-active peptides. Here we report a more detailed study of those present in the defensive skin secretion of the Australasian giant white-lipped tree frog, Litoria infrafrenata, and, for the first time, we have identified three novel frenatins by deduction of primary structures from cDNAs that were cloned from a library constructed from lyophilized skin secretion using a recently-developed technique. All open-reading frames consisted of a putative signal peptide and an acidic pro-region followed by a single copy of a frenatin peptide. Processed peptides corresponding in molecular mass to the deduced molecular masses of frenatins (named 1.1, 3, 3.1 and 4.1) were identified in the same secretion sample using HPLC and mass spectroscopy. The application of this technique thus permits parallel peptidomic and transcriptomic analyzes on the same lyophilized skin secretion sample circumventing sacrifice of specimens from endangered herpetofauna.