Iterated mutual observation with genetic programming

"This paper introduces a simple model of interacting agents that learn to predict each other. For learning to predict the other's intended action we apply genetic programming. The strategy of an agent is rational and fixed. It does not change like in classical iterated prisoners dilemma models. Furthermore the number of actions an agent can choose from is infinite. Preliminary simulation results are presented. They show that by varying the population size of genetic programming, different learning characteristics can easily be achieved, which lead to quite different communication patterns." (author's abstract

In-vivo-Darstellung einer Sarcoptes-scabiei-Infestation mittels optischer Kohärenztomographie

&lt;b&gt;&lt;i&gt;Hintergrund: &lt;/i&gt;&lt;/b&gt;&lt;i&gt;Sarcoptes scabiei&lt;/i&gt; kann mit Hilfe verschiedener Darstellungsverfahren sichtbar gemacht werden. Mit der optischen Kohärenztomographie (OCT) lassen sich möglicherweise die bei Skabies-Infestation auftretenden Veränderungen der Hautmorphologie charakterisieren und der Parasit darstellen. &lt;b&gt;&lt;i&gt;Methoden:&lt;/i&gt;&lt;/b&gt; Fünf Patienten aus der Klinik für Dermatologie am Klinikum Augsburg und am Roskilde Hospital in Roskilde, Dänemark, wurden mit der optischen Kohärenztomographie (OCT; VivoSight®; Michelson Diagnostics Ltd., UK) untersucht. Der Nachweis der Milben erfolgte mittels Epilumineszenz; zur Bestätigung der Diagnose wurde eine lichtmikroskopische Untersuchung durchgeführt. &lt;b&gt;&lt;i&gt;Ergebnisse:&lt;/i&gt;&lt;/b&gt; Die OCT wies in vivo bei allen Patienten &lt;i&gt;S.-scabiei&lt;/i&gt;-Milben nach. Milben und Gänge wurden sichtbar gemacht und Einzelheiten des Ganginhalts dargestellt. &lt;b&gt;&lt;i&gt;Schlussfolgerung:&lt;/i&gt;&lt;/b&gt; Die OCT kann &lt;i&gt;S.-scabiei&lt;/i&gt;-Milben in vivo sichtbar machen, was dafür spricht, dass die OCT zur Untersuchung der Biologie der Milbe in vivo eingesetzt werden kann und eine frühzeitige Beurteilung einer gegen Krätzmilben wirkenden Therapie ermöglicht. Die OCT ist in der Lage, Strukturen in der Haut mit einer Auflösung von 8 µm darzustellen. Somit könnte dieses Verfahren eine rasche, nichtinvasive, In-vivo-Diagnose und -Untersuchung von Infestationen ermöglichen.</jats:p

Investigating the role of filamin C in Belgian patients with frontotemporal dementia linked to GRN deficiency in FTLD-TDP brains

TAR DNA-binding protein 43 (TDP-43) inclusions are pathological hallmarks of patients with frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS). Loss of TDP-43 in zebrafish engenders a severe muscle and vascular phenotype with a concomitant elevation of filamin C (FLNC) levels, an observation confirmed in the frontal cortex of FTLD-TDP patients. Here, we aimed to further assess the contribution of FLNC to frontotemporal dementia (FTD) etiology. We conducted a mutational screening of FLNC in a cohort of 529 unrelated Belgian FTD and FTD-ALS patients, and a control cohort of 920 unrelated and age-matched individuals. Additionally we performed an in-depth characterization of FLNC expression levels in FTD patients and a murine FTD model. In total 68 missense variants were identified of which 19 (MAF C) loss-of-function mutation. Increased FLNC levels were, to a lesser extent, also identified in a FLNC p.V831I variant carrier and in FTD patients with the p.R159H mutation in valosin-containing protein (VCP). The GRN-associated increase of FLNC was confirmed in the frontal cortex of aged Grn knockout mice starting at 16-18 months of age. Combined quantitative proteomic and bioinformatic analyses of the frontal cortex of FTD patients possessing elevated FLNC levels, identified multiple altered protein factors involved in accelerated aging, neurodegeneration and synaptogenesis. Our findings further support the involvement of aberrant FLNC expression levels in FTD pathogenesis. Identification of increased FLNC levels in aged Grn mice and impaired pathways related to aging and neurodegeneration, implies a potential role for FLNC in mediating or accelerating the aging process

Prevalence of Borderline Personality Disorder in University Samples: Systematic Review, Meta-Analysis and Meta-Regression.

OBJECTIVE: To determine pooled prevalence of clinically significant traits or features of Borderline Personality Disorder among college students, and explore the influence of methodological factors on reported prevalence figures, and temporal trends. DATA SOURCES: Electronic databases (1994-2014: AMED; Biological Abstracts; Embase; MEDLINE; PsycARTICLES; CINAHL Plus; Current Contents Connect; EBM Reviews; Google Scholar; Ovid Medline; Proquest central; PsychINFO; PubMed; Scopus; Taylor & Francis; Web of Science (1998-2014), and hand searches. STUDY SELECTION: Forty-three college-based studies reporting estimates of clinically significant BPD symptoms were identified (5.7% of original search). DATA EXTRACTION: One author (RM) extracted clinically relevant BPD prevalence estimates, year of publication, demographic variables, and method from each publication or through correspondence with the authors. RESULTS: The prevalence of BPD in college samples ranged from 0.5% to 32.1%, with lifetime prevalence of 9.7% (95% CI, 7.7-12.0; p &lt; .005). Methodological factors contributing considerable between-study heterogeneity in univariate meta-analyses were participant anonymity, incentive type, research focus and participant type. Study and sample characteristics related to between study heterogeneity were sample size, and self-identifying as Asian or "other" race. The prevalence of BPD varied over time: 7.8% (95% CI 4.2-13.9) between 1994 and 2000; 6.5% (95% CI 4.0-10.5) during 2001 to 2007; and 11.6% (95% CI 8.8-15.1) from 2008 to 2014, yet was not a source of heterogeneity (p = .09). CONCLUSIONS: BPD prevalence estimates are influenced by the methodological or study sample factors measured. There is a need for consistency in measurement across studies to increase reliability in establishing the scope and characteristics of those with BPD engaged in tertiary study

A genetic programming approach to development of clinical prediction models: A case study in symptomatic cardiovascular disease

BACKGROUND:Genetic programming (GP) is an evolutionary computing methodology capable of identifying complex, non-linear patterns in large data sets. Despite the potential advantages of GP over more typical, frequentist statistical approach methods, its applications to survival analyses are rare, at best. The aim of this study was to determine the utility of GP for the automatic development of clinical prediction models. METHODS:We compared GP against the commonly used Cox regression technique in terms of the development and performance of a cardiovascular risk score using data from the SMART study, a prospective cohort study of patients with symptomatic cardiovascular disease. The composite endpoint was cardiovascular death, non-fatal stroke, and myocardial infarction. A total of 3,873 patients aged 19-82 years were enrolled in the study 1996-2006. The cohort was split 70:30 into derivation and validation sets. The derivation set was used for development of both GP and Cox regression models. These models were then used to predict the discrete hazards at t = 1, 3, and 5 years. The predictive ability of both models was evaluated in terms of their risk discrimination and calibration using the validation set. RESULTS:The discrimination of both models was comparable. At time points t = 1, 3, and 5 years the C-index was 0.59, 0.69, 0.64 and 0.66, 0.70, 0.70 for the GP and Cox regression models respectively. At the same time points, the calibration of both models, which was assessed using calibration plots and the generalization of the Hosmer-Lemeshow test statistic, was also comparable, but with the Cox model being better calibrated to the validation data. CONCLUSION:Using empirical data, we demonstrated that a prediction model developed automatically by GP has predictive ability comparable to that of manually tuned Cox regression. The GP model was more complex, but it was developed in a fully automated way and comprised fewer covariates. Furthermore, it did not require the expertise normally needed for its derivation, thereby alleviating the knowledge elicitation bottleneck. Overall, GP demonstrated considerable potential as a method for the automated development of clinical prediction models for diagnostic and prognostic purposes

Empathie bei Depression: Egozentrik- und Altrozentrik-Bias und die Rolle von Alexithymie

Background: Major depressive disorder (MDD) and alexithymia have both been associated with deficits in empathy. However, the exact nature of these deficits remains unclear. We examined under which conditions MDD patients with high and low alexithymia show empathy deficits. We particularly tested empathic abilities in situations when inhibition of self-related emotional states is either required or when it is not. Methods: 29 inpatients treated for MDD with low and high alexithymia (low: n=11, high n=18) and 42 healthy controls (low: n=28, high: n=14) performed a paradigm based on tactile stimulation assessing emotional egocentricity. Empathic judgments can be measured in this task by particularly differentiating between events where emotional states of self and other differ and inhibition of self-related emotional states is required, and events where they do not differ and thus the prediction of the emotional state of others can be based on a simple projection mechanism. Moreover we used the Interpersonal Reactivity Index- questionnaire (IRI) measuring trait empathy. Results: In events where simple projection was sufficient, only alexithymia but not MDD was associated with decreased empathy. However, when inhibition of self-related emotional states was required, depressed patients – independent of alexithymia - showed an egocentric bias during empathic judgments and an altercentric bias during self-emotion judgments. The latter finding possibly suggests heightened emotional contagion indicated by heightened personal distress shown by MDD patients (IRI) and a positive correlation of personal distress (IRI) and the altercentric bias across the entire sample. Alexithymia was associated with decreased egocentric bias independent of depression. Conclusion: These results suggest intact basic empathic abilities in MDD patients, when alexithymia is accounted for and simple projection mechanisms can be used for empathic judgments. However, in situations where emotional states of self and other differ and inhibition of self-related emotional states is needed, MDD patients are prone to egocentric and altercentric biases suggesting difficulties to empathically relate to the other’s incongruent emotional state.Hintergrund: Sowohl schwere depressive Episoden als auch Alexithymie sind in Zusammenhang mit Empathie-Defiziten gebracht worden. Das exakte Wesen dieser Defizite blieb bisher jedoch unklar. In dieser Studie testeten wir, unter welchen Bedingungen depressive Patienten mit hohen bzw. niedrigen Alexithymie- Werten verminderte Empathie zeigen. Wir testeten Empathiefähigkeit insbesondere in solchen Situationen, in denen eine Inhibition des eigenen emotionalen Zustandes entweder notwendig oder nicht notwendig ist. Methoden: 29 zum Zeitpunkt der Testung stationär aufgenommener Patienten mit depressiver Episode (niedrige Alexithymie-Werte: n=11, hohe Alexithymie-Werte: n=18) sowie 42 gesunde Kontrollprobanden (niedrige Alexithymie-Werte: n=28, hohe Alexithymie-Werte: n=14) vollzogen einen Emotionale-Egozentrizitäts-Test, der auf taktiler Stimulation basiert. Dieser Test misst empathische Einschätzungen, indem er Situationen differenziert, in denen sich einerseits der eigene emotionale Zustand von dem des Anderen unterscheidet und somit die Inhibition des eigenen emotionalen Zustands gefordert ist, bzw. wenn andererseits dies nicht der Fall ist und die empathische Voraussage des emotionalen Zustandes des Anderen auf einem einfachen Projektionsmechanismus basieren kann. Um trait Empathie zu messen, verwendeten wir darüber hinaus den Interpersonal Reactivity Index-Fragebogen (IRI). Ergebnisse: Nur Alexithymie, nicht aber eine depressive Episode reduzierte Empathie in Situationen, in denen ein einfacher Projektionsmechanismus für eine empathische Einschätzung genügt. Wenn jedoch die Inhibition der eigenen emotionalen Situation gefordert war, zeigten depressive Patienten - unabhängig von Alexithymie - einen egozentrischen Bias bei der empathischen Einschätzung der emotionalen Situation des Anderen und einen altrozentrischen Bias bei der Einschätzung der eigenen emotionalen Situation. Das letztere Ergebnis weist auf eine möglicherweise erhöhte emotionale Ansteckbarkeit bei depressiven Patienten hin. Der IRI ergab erhöhten empathischen Stress bei Depressiven und eine positive Korrelation zwischen empathischem Stress (IRI) und dem altrozentrischen Bias im Hinblick auf alle Probanden. Ebenfalls im Hinblick auf die gesamte Probandengruppe reduzierte Alexithymie die Größe des egozentrischen Bias. Schlussfolgerung: Diese Ergebnisse legen nahe, dass depressive Patienten intakte basale empathische Fähigkeiten bieten, wenn ein einfacher Projektionsmechanismus für empathische Urteile gefordert ist und gleichzeitig keine Alexithymie vorliegt. In Situationen, in denen sich die eigene emotionale Situation und die des Anderen unterscheiden, sind depressive Patienten jedoch empfänglich für einen egozentrischen bzw. altrozentrischen Bias. Dies verweist auf ihre Schwierigkeiten sich empathisch in emotional inkongruente Situationen des Anderen hineinzuversetzen

Reducing the Number of Fitness Evaluations in Graph Genetic Programming Using a Canonical Graph Indexed Database

We describe the genetic programming system GGP operating on graphs and introduce the notion of graph isomorphisms to explain how they influence the dynamics of GP. It is shown empirically how fitness databases can improve the performance of GP and how mapping graphs to a canonical form can increase these improvements by saving considerable evaluation time