Towards machines that understand people

The ability to estimate the state of a human partner is an insufficient basis on which to build cooperative agents. Also needed is an ability to predict how people adapt their behavior in response to an agent's actions. We propose a new approach based on computational rationality, which models humans based on the idea that predictions can be derived by calculating policies that are approximately optimal given human-like bounds. Computational rationality brings together reinforcement learning and cognitive modeling in pursuit of this goal, facilitating machine understanding of humans.peerReviewe

Trapping of 27 bp - 8 kbp DNA and immobilization of thiol-modified DNA using dielectrophoresis

Dielectrophoretic trapping of six different DNA fragments, sizes varying from the 27 to 8416 bp, has been studied using confocal microscopy. The effect of the DNA length and the size of the constriction between nanoscale fingertip electrodes on the trapping efficiency have been investigated. Using finite element method simulations in conjunction with the analysis of the experimental data, the polarizabilities of the different size DNA fragments have been calculated for different frequencies. Also the immobilization of trapped hexanethiol- and DTPA-modified 140 nm long DNA to the end of gold nanoelectrodes was experimentally quantified and the observations were supported by density functional theory calculations.Comment: 17 pages (1 column version), 8 figure

Spiritually ours, factually yours: Karelia and Russia in Finnish public consciousness

Diese Veröffentlichung erforscht auf der Grundlage einer Untersuchung der führenden finnischen Tageszeitung Helsingin Sanomat die Einstellungen und das Verständnis der Finnen zu Russland. Sie beschäftigt sich besonders mit der sogenannten Karelien-Frage und die Art und Weise, wie diese die öffentliche Diskussion in Finnland geprägt hat. Der Artikel versucht, meinungsbildende Verhaltensweisen in den spezifischen sozialen und kulturellen Verhältnissen zu untersuchen und erläutert die Meinungsbildung als gesellschaftliches Verhalten. Er bewertet, wie sich die öffentliche Meinung, wie sie sich auf der Leserbriefseite der Zeitung ausdrückt, entwickelt hat und von den größeren Veränderungen beeinflusst worden ist, die an der Grenze stattgefunden haben. Es gibt im Laufe der Zeit eindeutige Veränderungen sowohl in quantitativem als auch qualitativen Sinn. Dies lässt sich als Darstellung eines Trends zum allgemeinen Verschwinden in der Geschichte zusammenfassen, aber auch als periodisch auftretender Effekt und als Zusammenspiel zwischen bilateralen Beziehungen und allgemeineren geopolitischer Veränderungen.Based on an analysis of the leading Finnish newspaper, Helsingin Sanomat, this paper explores Finnish attitudes towards and understandings of Russia. It pays special attention to the so-called Karelia Question and the way it has shaped public discussion in Finland. The article seeks to investigate human signifying practices in the region’s specific social and cultural circumstances and explains meaning-making as a social practice. It evaluates how public opinion, as expressed in the letters page of the newspaper, has evolved and been affected by the broader changes that have occurred at the border. There are clear changes over time, both in a quantitative and qualitative sense. This may be summarised as representing a trend of general fading into history, but also as a more cyclical effect and as the interplay between bilateral relations and broader geopolitical changes

Nebular Line Emission During the Epoch of Reionization

Nebular emission lines associated with galactic HII regions carry information about both physical properties of the ionised gas and the source of ionising photons as well as providing the opportunity of measuring accurate redshifts and thus distances once a cosmological model is assumed. While nebular line emission has been extensively studied at lower redshift there are currently only few constraints within the epoch of reionisation (EoR, $z>6$), chiefly due to the lack of sensitive near-IR spectrographs. However, this will soon change with the arrival of the Webb Telescope providing sensitive near-IR spectroscopy covering the rest-frame UV and optical emission of galaxies in the EoR. In anticipation of Webb we combine the large cosmological hydrodynamical simulation Bluetides with photoionisation modelling to predict the nebular emission line properties of galaxies at $z=8\to 13$. We find good agreement with the, albeit limited, existing direct and indirect observational constraints on equivalent widths though poorer agreement with luminosity function constraints.Comment: 17 pages, accepted to MNRAS, significant modification from v1.0 data available at https://stephenmwilkins.github.io/BluetidesEmissionLines_Public

Segmentation of Striatal Brain Structures from High Resolution PET Images

We propose and evaluate an automatic segmentation method for extracting striatal brain structures (caudate, putamen, and ventral striatum) from parametric 11C-raclopride positron emission tomography (PET) brain images. We focus on the images acquired using a novel brain dedicated high-resolution (HRRT) PET scanner. The segmentation method first extracts the striatum using a deformable surface model and then divides the striatum into its substructures based on a graph partitioning algorithm. The weighted kernel k-means algorithm is used to partition the graph describing the voxel affinities within the striatum into the desired number of clusters. The method was experimentally validated with synthetic and real image data. The experiments showed that our method was able to automatically extract caudate, ventral striatum, and putamen from the images. Moreover, the putamen could be subdivided into anterior and posterior parts. An automatic method for the extraction of striatal structures from high-resolution PET images allows for inexpensive and reproducible extraction of the quantitative information from these images necessary in brain research and drug development

Tau as a fluid biomarker of concussion and neurodegeneration

Concussion is predominant among the vast number of traumatic brain injuries that occur worldwide. Difficulties in timely identification, whether concussion led to neuronal injury or not, diagnosis and the lack of prognostic tools for adequate management could lead this type of brain injury to progressive neurodegenerative diseases. Tau has been extensively studied in recent years, particularly in repetitive mild traumatic brain injuries and sports-related concussions. Tauopathies, the group of neurodegenerative diseases, have also been studied with advanced functional imaging. Nevertheless, neurodegenerative diseases, such as chronic traumatic encephalopathy, are still conclusively diagnosed at autopsy. Here, we discuss the diagnostic dilemma and the relationship between concussion and neurodegenerative diseases and review the literature on tau as a promising biomarker for concussion