Generic task problem solvers in Soar

Two trends can be discerned in research in problem solving architectures in the last few years. On one hand, interest in task-specific architectures has grown, wherein types of problems of general utility are identified, and special architectures that support the development of problem solving systems for those types of problems are proposed. These architectures help in the acquisition and specification of knowledge by providing inference methods that are appropriate for the type of problem. However, knowledge based systems which use only one type of problem solving method are very brittle, and adding more types of methods requires a principled approach to integrating them in a flexible way. Contrasting with this trend is the proposal for a flexible, general architecture contained in the work on Soar. Soar has features which make it attractive for flexible use of all potentially relevant knowledge or methods. But as the theory Soar does not make commitments to specific types of problem solvers or provide guidance for their construction. It was investigated how task-specific architectures can be constructed in Soar to retain as many of the advantages as possible of both approaches. Examples were used from the Generic Task approach for building knowledge based systems. Though this approach was developed and applied for a number of problems, the ideas are applicable to other task-specific approaches as well

Trajectory of social isolation following hip fracture: an analysis of the English Longitudinal Study of Ageing (ELSA) cohort

Background: social isolation is defined as a lack of meaningful and sustained communication or interactions with social networks. There is limited understanding on the prevalence of social isolation and loneliness in people following hip fracture and no previous understanding of how this changes over time. Objective: to determine the prevalence and trajectory of social isolation and loneliness before a hip fracture, during the recovery phase and a minimum of 2 years post-hip fracture in an English population. Methods: data were from the English Longitudinal Study of Ageing (ELSA) cohort (2004/5–2014/15). The sample comprised of 215 participants who had sustained a hip fracture. Measures of social isolation and loneliness were analysed through multilevel modelling to determine their trajectories during three-time intervals (pre-fracture; interval at hip fracture and recovery; minimum 2 years post-fracture). The prevalence of social isolation and loneliness were determined pre- and post-fracture. Results: prevalence of social isolation was 19% post-hip fracture and loneliness 13% post-hip fracture. There was no statistically significant change in social isolation pre-fracture compared to a minimum of 2 years post-fracture (P = 0.78). Similarly, there was no statistically significant change in loneliness pre-fracture compared to a minimum of 2 years post-fracture (P = 0.12). Conclusion: this analysis has determined that whilst social isolation and loneliness do not change over time following hip fracture, these remain a significant problem for this population. Interventions are required to address these physical and psychological health needs. This is important as they may have short and longer term health benefits for people post-hip fracture

Changes in social isolation and loneliness following total hip and knee arthroplasty: longitudinal analysis of the English Longitudinal Study of Ageing (ELSA) cohort

Objective: To determine the prevalence and change in social isolation and loneliness in people before and after THA and TKA in England. Design: The English Longitudinal Study of Ageing dataset, a prospective study of community-dwelling older adults, was used to identify people who had undergone primary THA or TKA because of osteoarthritis. Social isolation was assessed using the ELSA Social Isolation Index. Loneliness was evaluated using the Revised University of California, Los Angeles (UCLA) Loneliness Scale. The prevalence of social isolation and loneliness were calculated and multilevel modelling was performed to assess the potential change of these measures before arthroplasty, within a two-year operative-recovery phase and a following two-year follow-up. Results: The sample consisted of 393 people following THA and TKA. The prevalence of social isolation and loneliness changed from 16.9% and 18.8% pre-operative to 21.8% and 18.9% at the final post-operative follow-up respectively. This was not a statistically significant change for either measure (p=0.15; p=0.74). There was a significant difference in social isolation at the recovery phase compared to the pre-operative phase (p=0.01), where people following arthroplasty reported an increase in social isolation (16.9% to 21.4%). There was no significant difference between the assessment phases in respect to UCLA Loneliness Scale score (p≥0.74). Conclusions: Given the negative physical and psychological consequences which social isolation and loneliness can have on individuals following THA or TKA, clinicians should be mindful of this health challenge for this population. The reported prevalence of social isolation and loneliness suggests this is an important issue

Trajectory of physical activity following total hip and knee arthroplasty: data from the English Longitudinal Study of Ageing (ELSA) cohort

Purpose: To determine the prevalence and trajectory of physical activity levels in people before and after total hip (THA) and total knee arthroplasty (TKA).  Materials and Methods: An analysis of the English Longitudinal Study of Ageing (ELSA) (2004/5 to 2014/15) cohort study, a prospective study of community-dwelling older adults. 201 people who received a THA or TKA for the management of osteoarthritis were identified. Physical activity was assessed through the frequency of engagement in sedentary, mild, moderate and high physical activity levels pre-operatively, during the recovery phase and a minimum of two years’ post-operatively.  Results: There was a statistically significant decrease in physical activity from the pre-arthroplasty phase to the operative-recovery phase (p<0.01), and a significant increase in physical activity from the operative-recovery phase to final follow-up (p=0.05). However, overall there was no significant change in physical activity from pre-operatively to final follow-up where prevalence altered from 8% (95% Confidence Intervals (CI): 5% to 12%) to 13% (95% CI: 9% to 18%)(p=0.15). Increasing age, male gender and greater depressive symptoms were explanatory variables associated with physical inactivity (p<0.02).  Conclusion: Physical activity does not increase following THA or TKA. A proportion of the arthroplasty population remain physically inactive

Association between musculoskeletal pain with social isolation and loneliness: analysis of the English Longitudinal Study of Ageing

Introduction: Musculoskeletal pain is a prevalent health challenge for all age groups worldwide, but most notably in older adults. Social isolation is the consequence of a decrease in social network size with a reduction in the number of social contacts. Loneliness is the psychological embodiment of social isolation and represents an individual’s perception of dissatisfaction in the quality or quantity of their social contacts. This study aims to determine whether a relationship exists between musculoskeletal pain and social isolation and loneliness. Methods: A cross-sectional analysis of the English Longitudinal Study of Ageing (ELSA) cohort was undertaken. ELSA is a nationally representative sample of the non-institutionalised population of individuals aged 50 years and over based in England. Data were gathered on social isolation through the ELSA Social Isolation Index, loneliness through the University of California, Los Angeles (UCLA) Loneliness Scale and musculoskeletal pain. Data for covariates included physical activity, depression score, socioeconomic status, access to transport and demographic characteristics. Logistic regression analyses were undertaken to determine the relationship between social isolation and loneliness with pain and the additional covariates. Results: A total of 9299 participants were included in the analysis. This included 4125 (44.4%) males, with a mean age of 65.8 years. There was a significant association where social isolation was lower for those in pain (odd ratio (OR): 0.87; 95% confidence intervals (CI): 0.75 to 0.99), whereas the converse occurred for loneliness where this was higher for those in pain (OR: 1.15; 95% CI: 1.01 to 1.31). Age, occupation, physical activity and depression were all associated with increased social isolation and loneliness. Conclusion: People who experience chronic musculoskeletal pain are at greater risk of being lonely, but at less risk of being socially isolated. Health professionals should consider the wider implications of musculoskeletal pain on individuals, to reduce the risk of negative health implications associated with loneliness from impacting on individual’s health and well-being

The contribution of OCTN1/2 variants within the IBD5 locus to disease susceptibility and severity in Crohn's disease

Background and Aims: Recent data suggest that polymorphisms in the organic cation transporter (OCTN) genes OCTN1 (SLC22A4) and OCTN2 (SLC22A5) represent disease-causing mutations within the IBD5 locus (chromosome 5q31). We investigated associations with disease susceptibility, phenotype, and evidence for epistasis with CARD15 in 679 patients with Crohn’s disease (CD) or ulcerative colitis (UC). Methods: A total of 374 patients with CD, 305 patients with UC, and 294 healthy controls (HCs) were studied. Genotyping for single nucleotide polymorphisms IGR2096, IGR2198, and IGR2230, OCTN1 variant (SLC22A4 1672C→T), and OCTN2 variant (SLC22A5 −207G→C) was performed using the TaqMan system. Results: The IBD5 OCTN1 and OCTN2 polymorphisms were in strong linkage disequilibrium (D′, >0.959). IGR2198 variant allele frequency (49.1% vs 40.8%; P = .0046) and homozygosity (21% vs 14.8%; P = .044) were associated with CD versus HCs. Variant allelic frequency of OCTN1 (53.6% vs 43%; P = .0008) and OCTN2 (56.1% vs 48.4%; P = .0092) polymorphisms and homozygosity for the OCTN1/2-TC haplotype (28.4% vs 16%; P = .0042) were associated with CD versus HCs. IGR2198 homozygosity and TC homozygosity were associated with stricturing/penetrating disease at follow-up (P = .011 and P = .011, respectively) and disease progression (P = .038 and P = .049, respectively) on univariate analysis and with need for surgery on multivariate analysis (P = .016 and P = .004, respectively). In the absence of the IBD5 risk haplotype, no association of OCTN1/2 variants with CD was detected. No associations were seen with UC. Conclusions: The IBD5 locus influences susceptibility, progression, and need for surgery in CD. However, the contribution of OCTN1/2 variants is not independent of the IBD5 haplotype; a causative role for these genes remains plausible but is not yet proven. Further genetic, functional, and expression data are now required. </p

Trajectory of physical activity after hip fracture: An analysis of community-dwelling individuals from the English Longitudinal Study of Ageing

Introduction: To analyse physical activity participation in a community-dwelling people in England with hip fracture the interval prior to fracture, in the fracture recovery period, and a minimum of two years post-fracture. Materials and methods: 215 individuals were identified from the English Longitudinal Study of Ageing cohort (2002–2014) who sustained a hip fracture following a fall and for whom data were available on physical activity participation relating to the period pre-fracture, within-fracture recovery phase and post-fracture (minimum of two years). Physical activity was assessed using the validated ELSA physical activity questionnaire. Prevalence of ‘low’ physical activity participation was calculated and multi-level modelling analyses were performed to explore physical activity trajectories over the follow-up phase, and whether age, depression, gender and frailty were associated with physical activity participation. Results: Prevalence of low physical activity participation within two years prior to hip fracture was 16.7% (95% Confidence Intervals (CI): 11.6% to 21.8%). This increased at the final follow-up phase to 21.3% (95% CI: 15.1% to 27.6%). This was not a statistically significant change (P = 0.100). Age (P = 0.005) and frailty (P < 0.001) were statistically significant explanatory variables (P = 0.005) where older age and greater frailty equated to lower physical activity participation. Neither gender (P = 0.288) nor depression (P = 0.121) were significant explanatory variables. Conclusion: Physical activity levels do not significantly change between pre-fracture to a minimum of two years post-hip fracture for community-dwelling individuals. This contrasts with previous reports of reduced mobility post-hip fracture, suggesting that ‘physical activity’ and ‘mobility’ should be considered as separate outcomes in this population

Palatability of teff grass by horses

Most forages commonly used to feed horses have potential detriments including blister beetles or excessive fiber concentrations. Teff grass (T), a warm-season annual forage, has the potential to be a good alternative for horses because of its lack of observed disorders. Our objective was to compare preference by horses for T harvested under different conditions with that of bermudagrass (B) harvested at two maturities. Six different forages were evaluated: T harvested at the late vegetative stage (TLV), at late bloom but that incurred 33 mm of rainfall between mowing and baling (TLBR), with caryopsis visible (TES), or at soft dough (TSD), and B harvested at late vegetative (BLV) and mid-bloom (BMB) growth stages. Five mature horses were used in a balanced incomplete block design where each horse received a different combination of 4 forages each day for 6 d. The 4 different forages were suspended in hay nets in each corner of each stall, and each hay was offered at 50% of the average daily hay consumption measured during a 12-d adaptation period. Forage preference as measured by individual forage dry matter (DM) consumption (kg and % of total DM consumed across the 4 forages) was greatest (P \u3c 0.05) from TLV followed by BLV. Preference (kg and % of total DM consumed) of BMB was greater (P \u3c 0.05) than that of TMBR, TES, and TSD, which did not differ from each other (P ≥ 0.63). Therefore, within a specific growth stage, horses apparently preferred teff grass, but effects of maturity and rainfall had a more dramatic effect on preference by horses than forage species

Self-Assembly of Patchy Particles into Polymer Chains: A Parameter-Free Comparison between Wertheim Theory and Monte Carlo Simulation

We numerically study a simple fluid composed of particles having a hard-core repulsion, complemented by two short-ranged attractive (sticky) spots at the particle poles, which provides a simple model for equilibrium polymerization of linear chains. The simplicity of the model allows for a close comparison, with no fitting parameters, between simulations and theoretical predictions based on the Wertheim perturbation theory, a unique framework for the analytic prediction of the properties of self-assembling particle systems in terms of molecular parameter and liquid state correlation functions. This theory has not been subjected to stringent tests against simulation data for ordering across the polymerization transition. We numerically determine many of the thermodynamic properties governing this basic form of self-assembly (energy per particle, order parameter or average fraction of particles in the associated state, average chain length, chain length distribution, average end-to-end distance of the chains, and the static structure factor) and find that predictions of the Wertheim theory accord remarkably well with the simulation results