Incremental Partial Matching of Descriptions in a Knowledge Representation Network

This thesis describes a description matcher for the KL-ONE knowledge representation language that is incremental and can perform partial matches. The matcher is incremental in that it can be suspended at any time, producing partial results, and later restarted. The matcher is partial in that it has a formalism for measuring the degree to which two descriptions match. Both features are supported by using four different scalar metrics for the degree of match of two descriptions: a lower bound, an upper bound, a base value, and a current estimate

Exercise therapy in adults with serious mental illness: a systematic review and meta-analysis

Background: Individuals with serious mental illness are at a higher risk of physical ill health. Mortality rates are at least twice those of the general population with higher levels of cardiovascular disease, metabolic disease, diabetes, and respiratory illness. Although genetics may have a role in the physical health problems of these patients, lifestyle and environmental factors such as levels of smoking, obesity, poor diet, and low levels of physical activity also play a prominent part.<p></p> Objective: To conduct a systematic review and meta-analysis of randomised controlled trials comparing the effect of exercise interventions on individuals with serious mental illness.<p></p> Methods: Searches were made in Ovid MEDLINE, Embase, CINAHL, PsycINFO, Biological Abstracts on Ovid, and The Cochrane Library (January 2009, repeated January 2013) through to February 2013.<p></p> Results: Eight RCTs were identified in the systematic search. Six compared exercise versus usual care. One study assessed the effect of a cycling programme versus muscle strengthening and toning exercises. The final study compared the effect of adding specific exercise advice and motivational skills to a simple walking programme. Exercise programmes were noted by their heterogeneity in terms of the type of exercise intervention, setting, and outcome measures. The review found that exercise improved levels of exercise activity (n=13, standard mean difference [SMD] 1.81, CI 0.44 to 3.18, p = 0.01). No beneficial effect was found on negative (n = 84, SMD = -0.54, CI -1.79 to 0.71, p = 0.40) or positive symptoms of schizophrenia (n = 84, SMD = -1.66, CI -3.78 to 0.45, p = 0.12). No change was found on body mass index compared with usual care (n= 151, SMD = -0.24, CI -0.56 to 0.08, p = 0.14), or body weight (n = 77, SMD = 0.13, CI -0.32 to 0.58, p = 0.57). No beneficial effect was found on anxiety and depressive symptoms (n = 94, SMD = -0.26, CI -0.91 to 0.39, p = 0.43), or quality of life in respect of physical and mental domains. One RCT measured the effect of exercise on exercise intensity, attendance, and persistence at a programme. No significant effect was found on these measures.<p></p> Conclusions: This systematic review showed that exercise therapies can lead to a modest increase in levels of exercise activity but overall there was no noticeable change for symptoms of mental health, body mass index, and body weight.<p></p&gt

Ecological succession of a Jurassic shallow-water ichthyosaur fall.

After the discovery of whale fall communities in modern oceans, it has been hypothesized that during the Mesozoic the carcasses of marine reptiles created similar habitats supporting long-lived and specialized animal communities. Here, we report a fully documented ichthyosaur fall community, from a Late Jurassic shelf setting, and reconstruct the ecological succession of its micro- and macrofauna. The early 'mobile-scavenger' and 'enrichment-opportunist' stages were not succeeded by a 'sulphophilic stage' characterized by chemosynthetic molluscs, but instead the bones were colonized by microbial mats that attracted echinoids and other mat-grazing invertebrates. Abundant cemented suspension feeders indicate a well-developed 'reef stage' with prolonged exposure and colonization of the bones prior to final burial, unlike in modern whale falls where organisms such as the ubiquitous bone-eating worm Osedax rapidly destroy the skeleton. Shallow-water ichthyosaur falls thus fulfilled similar ecological roles to shallow whale falls, and did not support specialized chemosynthetic communities

Social cognition and idiopathic isolated cervical dystonia

For a long time, cervical dystonia (CD) has been characterised only by disturbances in motor functioning. Despite accumulating evidence for symptomatology in various non-motor domains, to date no study has investigated social cognition in CD. The aim of this study was to compare performance of CD patients and healthy controls in neurocognitive and socio-cognitive domain. Twenty-five non-depressed patients with CD and 26 healthy controls underwent neuropsychological testing. This involved assessment of cognitive status (general intellect, verbal memory, and executive function), and socio-cognitive functions using a Theory of mind task and self-report on empathy and emotion regulation. In comparison to controls, CD patients displayed significantly decreased cognitive abilities, particularly in executive function and verbal memory tasks. Difficulties in inferring mental states on both cognitive and affective levels were also observed. The largest discrepancies were detected in understanding intentionality in others. Poorer performance in cognitive and socio-cognitive tasks was unrelated to severity of the disease. This is the first evidence of compromised socio-cognitive functions in CD patients, highlighting this domain as another facet of non-motor symptoms of this disease. Future studies should advance our understanding of the extent, nature, and time course of these deficits in other aspects of social cognition in this patient population

Light-Dependant Biostabilisation of Sediments by Stromatolite Assemblages

For the first time we have investigated the natural ecosystem engineering capacity of stromatolitic microbial assemblages. Stromatolites are laminated sedimentary structures formed by microbial activity and are considered to have dominated the shallows of the Precambrian oceans. Their fossilised remains are the most ancient unambiguous record of early life on earth. Stromatolites can therefore be considered as the first recognisable ecosystems on the planet. However, while many discussions have taken place over their structure and form, we have very little information on their functional ecology and how such assemblages persisted despite strong eternal forcing from wind and waves. The capture and binding of sediment is clearly a critical feature for the formation and persistence of stromatolite assemblages. Here, we investigated the ecosystem engineering capacity of stromatolitic microbial assemblages with respect to their ability to stabilise sediment using material from one of the few remaining living stromatolite systems (Highborne Cay, Bahamas). It was shown that the most effective assemblages could produce a rapid (12–24 h) and significant increase in sediment stability that continued in a linear fashion over the period of the experimentation (228 h). Importantly, it was also found that light was required for the assemblages to produce this stabilisation effect and that removal of assemblage into darkness could lead to a partial reversal of the stabilisation. This was attributed to the breakdown of extracellular polymeric substances under anaerobic conditions. These data were supported by microelectrode profiling of oxygen and calcium. The structure of the assemblages as they formed was visualised by low-temperature scanning electron microscopy and confocal laser microscopy. These results have implications for the understanding of early stromatolite development and highlight the potential importance of the evolution of photosynthesis in the mat forming process. The evolution of photosynthesis may have provided an important advance for the niche construction activity of microbial systems and the formation and persistence of the stromatolites which came to dominate shallow coastal environments for 80% of the biotic history of the earth

Similarities and differences in the dolomitization history of two coeval Middle Triassic carbonate platforms, Balaton Highland, Hungary

Dolomitization of platform carbonates is commonly the result of multiphase processes. Documentation of the complex dolomitization history is difficult if completely dolomitized sections are studied. Two Middle Anisian sections representing two coeval carbonate platforms were investigated and compared in the present study. Both sections are made up of meter-scale peritidal–lagoonal cycles with significant pedogenic overprint. One of the sections contains non-dolomitized, partially dolomitized, and completely dolomitized intervals, whereas the other is completely dolomitized. Based on investigations of the partially dolomitized section, penecontemporaneous dolomite formation and/or very early post-depositional dolomitization were identified in various lithofacies types. In shallow subtidal facies, porphyrotopic dolomite was found preferentially in microbial micritic fabrics. Microbially induced dolomite precipitation and/or progressive replacement of carbonate sediments could be interpreted for stromatolites. Cryptocrystalline to very finely crystalline dolomite, probably of pedogenic origin, was encountered in paleosoil horizons. Fabric-destructive dolomite commonly found below these horizons was likely formed via reflux of evaporated seawater. As a result of the different paleogeographic settings of the two platforms, their shallow-burial conditions were significantly different. One of the studied sections was located at the basinward platform margin where pervasive fabric-retentive dolomitization took place in a shallow-burial setting, probably via thermal convection. In contrast, in the area of the other, smaller platform shallow-water carbonates were covered by basinal deposits, preventing fluid circulation and accordingly pervasive shallow-burial dolomitization. In the intermediate to deep burial zone, recrystallization of partially dolomitized limestone and occlusion of newly opened fractures and pores by coarsely crystalline dolomite took place

Missing Links: Referrer Behavior and Job Segregation

How does referral recruitment contribute to job segregation, and what can organizations do about it? Current theory on network effects in the labor market emphasizes the job-seeker perspective, focusing on the segregated nature of job-seekers’ information and contact networks, and leaves little role for organizational influence. But employee referrals are necessarily initiated from within a firm by referrers. We argue that referrer behavior is the missing link that can help organizations manage the segregating effects of referring. Adopting the referrer’s perspective of the process, we develop a computational model which integrates a set of empirically documented referrer behavior mechanisms gleaned from extant organizational case studies. Using this model, we compare the segregating effects of referring when these behaviors are inactive to the effects when the behaviors are active. We show that referrer behaviors substantially boost the segregating effects of referring. This impact of referrer behavior presents an opportunity for organizations. Contrary to popular wisdom, we show that organizational policies designed to influence referrer behaviors can mitigate most if not all of the segregating effects of referring