Assessing the impact of modeling limits on intelligent systems

The knowledge bases underlying intelligent systems are validated. A general conceptual framework is provided for considering the roles in intelligent systems of models of physical, behavioral, and operational phenomena. A methodology is described for identifying limits in particular intelligent systems, and the use of the methodology is illustrated via an experimental evaluation of the pilot-vehicle interface within the Pilot's Associate. The requirements and functionality are outlined for a computer based knowledge engineering environment which would embody the approach advocated and illustrated in earlier discussions. Issues considered include the specific benefits of this functionality, the potential breadth of applicability, and technical feasibility

Pilot interaction with automated airborne decision making systems

The current research is focused on detection of human error and protection from its consequences. A program for monitoring pilot error by comparing pilot actions to a script was described. It dealt primarily with routine errors (slips) that occurred during checklist activity. The model to which operator actions were compared was a script. Current research is an extension along these two dimensions. The ORS fault detection aid uses a sophisticated device model rather than a script. The newer initiative, the model-based and constraint-based warning system, uses an even more sophisticated device model and is to prevent all types of error, not just slips or bad decision

APPLYING PRINCIPAL COMPONENT ANALYSIS TO SOIL-LANDSCAPE RESEARCH-QUANTIFYING THE SUBJECTIVE

Principal component analysis is a multivariate statistical procedure that can be used to identify factors (correlated subsets of variables) in large data sets. This statistical method appears useful for scientists investigating soil processes, but it has received little attention. Reported applications of principal component analysis share a common fault--subjective, user-specified analytical options apparently are not recognized, for they are not discussed. Reported data sets are often small, have low observations-per-variable ratios, and lack tests of robustness. A large soil data set is used to demonstrate systematic procedures for an optimum rotated principal component solution. This solution retained 21 variables aligned among four clean and logical factors, and extracted 79% of the variance. Robustness was confirmed by comparison with common factor analysis solutions. When carefully applied, the presented guidelines should enhance scientists\u27 abilities to identify and transfer knowledge about multivariate data sets, and should allow different scientists to independently arrive at similar factor solutions

γ2˘7\gamma\u27-Realizability and Other Musings on Inverse Domination

We introduce and study $\gamma\u27$-realizable sequences. For a finite, simple graph $G$ containing no isolated vertices, $I \subseteq V(G)$ is said to be an \emph{inverse dominating set} if $I$ dominates all of $G$ and $I$ is contained by the complement of some minimum dominating set $D$. Define a sequence of positive integers $(x_1, \ldots , x_n)$ to be \emph{$\gamma\u27$-realizable} if there exists a graph $G$ having exactly $n$ distinct minimum dominating sets $D_1, \ldots, D_n$ where for each $i \in \{1, \ldots, n\}$, the minimum size of an inverse dominating set in $V(G) \setminus D_i$ is equal to $x_i$. In this work, we show which sequences having minimum entry 2 or less are $\gamma\u27$-realizable. We then detail a few observations and results arising during our investigations that may prove useful in future research

Development and characterisation of a novel three-dimensional inter-kingdom wound biofilm model

Chronic diabetic foot ulcers are frequently colonised and infected by polymicrobial biofilms that ultimately prevent healing. This study aimed to create a novel in vitro inter-kingdom wound biofilm model on complex hydrogel-based cellulose substrata to test commonly used topical wound treatments. Inter-kingdom triadic biofilms composed of Candida albicans, Pseudomonas aeruginosa, and Staphylococcus aureus were shown to be quantitatively greater in this model compared to a simple substratum when assessed by conventional culture, metabolic dye and live dead qPCR. These biofilms were both structurally complex and compositionally dynamic in response to topical therapy, so when treated with either chlorhexidine or povidone iodine, principal component analysis revealed that the 3-D cellulose model was minimally impacted compared to the simple substratum model. This study highlights the importance of biofilm substratum and inclusion of relevant polymicrobial and inter-kingdom components, as these impact penetration and efficacy of topical antiseptics

Vitamin D deficiency is associated with IL-6 levels and monocyte activation in HIV-infected persons

Immune activation plays a key role in HIV pathogenesis. Markers of inflammation have been associated with vitamin D deficiency in the general population. Studies have also demonstrated associations of vitamin D deficiency with increased risk of HIV progression and death. The relationship between persistent inflammation and immune activation during chronic HIV infection and vitamin D deficiency remains unclear.Cryopreserved specimens were analyzed from 663 participants at the time of enrollment from the Study to Understand the Natural History of HIV/AIDS in the Era of Effective Therapy (SUN Study) from 2004 to 2006. Biomarkers of inflammation, atherosclerosis, and coagulation were measured using enzyme-linked immunosorbent assays (ELISAs) and electrochemiluminescence. 25(OH)D, the stable precursor form of vitamin D, was measured using a radioimmunoassay with levels defined as: normal (≥30ng/mL), insufficient (20-29 ng/mL) and deficient (<20 ng/mL). Monocyte phenotypes were assessed by flow cytometry. Linear and logistic regression models were used to determine statistical associations between biomarkers and vitamin D deficiency.25(OH)D levels were deficient in 251 (38%) participants, insufficient in 222 (34%), and normal in 190 (29%). Patients with vitamin D deficiency, when compared to those with insufficient or normal vitamin D levels, had increased levels of IL-6 (23%; p<0.01), TNF-α (21%, p = 0.03), D-dimer (24%, p = 0.01), higher proportions of CD14dimCD16+ (22%, p<0.01) and CX3CR1+ monocytes (48%; p<0.001) and decreased frequency of CCR2+ monocytes (-3.4%, p<0.001). In fully adjusted models, vitamin D associations with abnormal biomarker levels persisted for IL-6 levels and CX3CR1+ and CCR2+ phenotypes.Vitamin D deficiency is associated with greater inflammation and activated monocyte phenotypes. The role of vitamin D deficiency in persistent immune activation and associated complications during chronic HIV disease should be further evaluated as a possible target for intervention

Prevalence, incidence, and clearance of anal high-risk human papillomavirus infection among HIV-infected men in the SUN study

BACKGROUND: The natural history of anal human papilloma virus (HPV) infection among human immunodeficiency virus (HIV)-infected men is unknown. METHODS: Annually, from 2004 to 2012, we examined baseline prevalence, incidence, and clearance of anal HPV infection at 48 months, and associated factors among HIV-infected men. RESULTS: We examined 403 men who have sex with men (MSM) and 96 men who have sex with women (MSW) (median age 42 years for both, 78% versus 81% prescribed cART, median CD4+ T-lymphocyte cell count 454 versus 379 cells/mm3, and 74% versus 75% had undetectable viral load, respectively). Type 16 prevalence among MSM and MSW was 38% versus 14% (P \u3c .001), and incidence 24% versus 7% (P = .001). Type 18 prevalence was 24% versus 8% (P \u3c .001), and incidence 13% versus 4% (P = .027). Among MSM and MSW, clearance of prevalent HPV 16 and HPV 18 was 31% and 60% (P = .392), and 47% and 25% (P = .297), respectively. Among MSM, receptive anal sex (with or without a condom) was associated with persistent HPV 16 (OR 2.24, P \u3c .001). CONCLUSIONS: MSM had higher prevalence and incidence of HPV than MSW, but similar clearance. Receptive anal sex may predict cancer risk among HIV-infected MSM