Universality of hypercubic random surfaces

We study universality properties of the Weingarten hyper-cubic random surfaces. Since a long time ago the model with a local restriction forbidding surface self-bendings has been thought to be in a different universality class from the unrestricted model defined on the full set of surfaces. We show that both models in fact belong to the same universality class with the entropy exponent gamma = 1/2 and differ by finite size effects which are much more pronounced in the restricted model.Comment: 8 pages, 3 figure

The Hindu Presence in Europe and Implications of Interfaith Dialogue

The World\u27s Parliament of Religions held in Chicago in 1893 is often referred to as the catalytic start of organized interfaith activities in Canada and the United States. Europe, however, cannot look back to such a pioneering event. One may point to the Religions of the Empire Conference, held in 1924 in conjunction with the British Empire Exhibition in London, or the World Congress of Faiths in 1936. These incipient initiatives of an interfaith dialogue were confined to Great Britain only and did not reach the continent

Mapping the qualitative evidence base on the use of research evidence in health policy-making: a systematic review

BACKGROUND; : The use of research evidence in health policy-making is a popular line of inquiry for scholars of public health and policy studies, with qualitative methods constituting the dominant strategy in this area. Research on this subject has been criticized for, among other things, disproportionately focusing on high-income countries; overemphasizing 'barriers and facilitators' related to evidence use to the neglect of other, less descriptive concerns; relying on descriptive, rather than in-depth explanatory designs; and failing to draw on insights from political/policy studies theories and concepts. We aimed to comprehensively map the global, peer-reviewed qualitative literature on the use of research evidence in health policy-making and to provide a descriptive overview of the geographic, temporal, methodological, and theoretical characteristics of this body of literature.; METHODS; : We conducted a systematic review following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. We searched nine electronic databases, hand-searched 11 health- and policy-related journals, and systematically scanned the reference lists of included studies and previous reviews. No language, date or geographic limitations were imposed.; RESULTS; : The review identified 319 qualitative studies on a diverse array of topics related to the use of evidence in health policy-making, spanning 72 countries and published over a nearly 40 year period. A majority of these studies were conducted in high-income countries, but a growing proportion of the research output in this area is now coming from low- and middle-income countries, especially from sub-Saharan Africa. While over half of all studies did not use an identifiable theory or framework, and only one fifth of studies used a theory or conceptual framework drawn from policy studies or political science, we found some evidence that theory-driven and explanatory (eg, comparative case study) designs are becoming more common in this literature. Investigations of the barriers and facilitators related to evidence use constitute a large proportion but by no means a majority of the work in this area.; CONCLUSION; : This review provides a bird's eye mapping of the peer reviewed qualitative research on evidence-to-policy processes, and has identified key features of - and gaps within - this body of literature that will hopefully inform, and improve, research in this area moving forward

Simple threshold rules solve explore/exploit trade‐offs in a resource accumulation search task

How, and how well, do people switch between exploration and exploitation to search for and accumulate resources? We study the decision processes underlying such exploration/exploitation trade‐offs using a novel card selection task that captures the common situation of searching among multiple resources (e.g., jobs) that can be exploited without depleting. With experience, participants learn to switch appropriately between exploration and exploitation and approach optimal performance. We model participants' behavior on this task with random, threshold, and sampling strategies, and find that a linear decreasing threshold rule best fits participants' results. Further evidence that participants use decreasing threshold‐based strategies comes from reaction time differences between exploration and exploitation; however, participants themselves report non‐decreasing thresholds. Decreasing threshold strategies that “front‐load” exploration and switch quickly to exploitation are particularly effective in resource accumulation tasks, in contrast to optimal stopping problems like the Secretary Problem requiring longer exploration

Medial parietal cortex encodes perceived heading direction in humans

The ability to encode and update representations of heading direction is crucial for successful navigation. In rats, head-direction cells located within the limbic system alter their firing rate in accordance with the animal's current heading. To date, however, the neural structures that underlie an allocentric or viewpoint-independent sense of direction in humans remain unknown. Here we used functional magnetic resonance imaging (fMRI) to measure neural adaptation to distinctive landmarks associated with one of four heading directions in a virtual environment. Our experiment consisted of two phases: a "learning phase," in which participants actively navigated the virtual maze; and a "test phase," in which participants viewed pairs of images from the maze while undergoing fMRI. We found that activity within the medial parietal cortex—specifically, Brodmann area 31—was modulated by learned heading, suggesting that this region contains neural populations involved in the encoding and retrieval of allocentric heading information in humans. These results are consistent with clinical case reports of patients with acquired lesions of medial posterior brain regions, who exhibit deficits in forming and recalling links between landmarks and directional information. Our findings also help to explain why navigation disturbances are commonly observed in patients with Alzheimer's disease, whose pathology typically includes the cortical region we have identified as being crucial for maintaining representations of heading direction

Scaling of neural responses to visual and auditory motion in the human cerebellum

The human cerebellum contains approximately half of all the neurons within the cerebrum, yet most experimental work in human neuroscience over the last century has focused exclusively on the structure and functions of the forebrain. The cerebellum has an undisputed role in a range of motor functions (Thach et al., 1992), but its potential contributions to sensory and cognitive processes are widely debated (Stoodley and Schmahmann, 2009). Here we used functional magnetic resonance imaging to test the hypothesis that the human cerebellum is involved in the acquisition of auditory and visual sensory data. We monitored neural activity within the cerebellum while participants engaged in a task that required them to discriminate the direction of a visual or auditory motion signal in noise. We identified a distinct set of cerebellar regions that were differentially activated for visual stimuli (vermal lobule VI and right-hemispheric lobule X) and auditory stimuli (right-hemispheric lobules VIIIA and VIIIB and hemispheric lobule VI bilaterally). In addition, we identified a region in left crus I in which activity correlated significantly with increases in the perceptual demands of the task (i.e., with decreasing signal strength), for both auditory and visual stimuli. Our results support suggestions of a role for the cerebellum in the processing of auditory and visual motion and suggest that parts of cerebellar cortex are concerned with tracking movements of objects around the animal, rather than with controlling movements of the animal itself (Paulin, 1993)

Dissociable representations of environmental size and complexity in the human hippocampus

The hippocampus is widely assumed to play a central role in representing spatial layouts in the form of "cognitive maps." It remains unclear, however, which properties of the world are explicitly encoded in the hippocampus, and how these properties might contribute to the formation of cognitive maps. Here we investigated how physical size and complexity, two key properties of any environment, affect memory-related neural activity in the human hippocampus. We used functional magnetic resonance imaging and a virtual maze-learning task to examine retrieval-related activity for three previously learned virtual mazes that differed systematically in their physical size and complexity (here defined as the number of distinct paths within the maze). Before scanning, participants learned to navigate each of the three mazes; hippocampal activity was then measured during brief presentations of static images from within each maze. Activity within the posterior hippocampus scaled with maze size but not complexity, whereas activity in the anterior hippocampus scaled with maze complexity but not size. This double dissociation demonstrates that environmental size and complexity are explicitly represented in the human hippocampus, and reveals a functional specialization for these properties along its anterior-posterior axis