Information Cascades: Evidence from An Experiment with Financial Market Professionals

Previous empirical studies of information cascades use either naturally occurring data or laboratory experiments with student subjects. We combine attractive elements from each of these lines of research by observing market professionals from the Chicago Board of Trade (CBOT) in a controlled environment. As a baseline, we compare their behavior to student choices in similar treatments. We further examine whether, and to what extent, cascade formation is influenced by both private signal strength and the quality of previous public signals, as well as decision heuristics that differ from Bayesian rationality. Analysis of over 1,500 individual decisions suggests that CBOT professionals are better able to discern the quality of public signals than their student counterparts. This leads to much different cascade formation. Further, while the behavior of students is consistent with the notion that losses loom larger than gains, market professionals are unaffected by the domain of earnings. These results are important in both a positive and normative sense.

Field Experiments on Anchoring of Economic Valuations

A pillar of behavioral research is the view that preferences are constructed during the value elicitation process, but it is unclear whether, and to what extent, such biases influence real market equilibria. This paper examines the “anchoring” phenomenon in the field. The first experiment produces evidence that inexperienced consumers can be anchored in the value elicitation process, yet there is little evidence that experienced agents are influenced by anchors. The second experiment finds that anchors have only transient effects on prices and quantities traded: aggregate market outcomes converge to the intersection of supply and demand after a few market periods.field experiment, anchoring, valuation, experience

Cognitive function and brain structure after recurrent mild traumatic brain injuries in young-to-middle-aged adults

Recurrent mild traumatic brain injuries (mTBIs) are regarded as an independent risk factor for developing dementia in later life. We here aimed to evaluate associations between recurrent mTBIs, cognition, and gray matter volume and microstructure as revealed by structural magnetic resonance imaging (MRI) in the chronic phase after mTBIs in young adulthood. We enrolled 20 young-to- middle-aged subjects, who reported two or more sports-related mTBIs, with the last mTBI > 6 months prior to study enrolment (mTBI group), and 21 age-, sex- and education matched controls with no history of mTBI (control group). All participants received comprehensive neuropsychological testing, and high resolution T1-weighted and diffusion tensor MRI in order to assess cortical thickness (CT) and microstructure, hippocampal volume, and ventricle size. Compared to the control group, subjects of the mTBI group presented with lower CT within the right temporal lobe and left insula using an a priori region of interest approach. Higher number of mTBIs was associated with lower CT in bilateral insula, right middle temporal gyrus and right entorhinal area. Our results suggest persistent detrimental effects of recurrent mTBIs on CT already in young-to-middle-aged adults. If additional structural deterioration occurs during aging, subtle neuropsychological decline may progress to clinically overt dementia earlier than in age-matched controls, a hypothesis to be assessed in future prospective trials

cSPider – Evaluation of a Free and Open-Source Automated Tool to Analyze Corticomotor Silent Period

Background The corticomotor silent period (CSP), as assessed noninvasively by transcranial magnetic stimulation (TMS) in the primary motor cortex, has been found to reflect intracortical inhibitory mechanisms. Analysis of CSP is mostly conducted manually. However, this approach is time-consuming, and comparison of results from different laboratories may be compromised by inter- rater variability in analysis. No open source program for automated analysis is currently available. Methods/Results Here, we describe cross-validation with the manual analysis of an in-house written automated tool to assess CSP (cSPider). Results from automated routine were compared with results of the manual evaluation. We found high inter-method reliability between automated and manual analysis (p<0.001), and significantly reduced time for CSP analysis (median = 10.3 sec for automated analysis of 10 CSPs vs. median = 270 sec for manual analysis of 10 CSPs). cSPider can be downloaded free of charge. Conclusion cSPider allows automated analysis of CSP in a reliable and time- efficient manner. Use of this open-source tool may help to improve comparison of data from different laboratories

A Pooled Data Analysis from Three Research Labs

Paired associative stimulation (PAS) is a widely used transcranial magnetic stimulation (TMS) paradigm to non-invasively induce synaptic plasticity in the human brain in vivo. Altered PAS-induced plasticity has been demonstrated for several diseases. However, researchers are faced with a high inter- and intra- subject variability of the PAS response. Here, we pooled original data from nine PAS studies from three centers and analyzed the combined dataset of 190 healthy subjects with regard to age dependency, the role of stimulation parameters and the effect of different statistical methods. We observed no main effect of the PAS intervention over all studies (F(2;362) = 0.44; p = 0.644). The rate of subjects showing the expected increase of motor evoked potential (MEP) amplitudes was 53%. The PAS effect differed significantly between studies as shown by a significant interaction effect (F(16;362) = 1.77; p = 0.034) but post-hoc testing did not reveal significant effects after correction for multiple tests. There was a trend toward increased variability of the PAS effect in older subjects. Acquisition parameters differed across studies but without systematically influencing changes in MEP-size. The use of post/baseline quotients systematically indicated stronger PAS effects than post/baseline difference or the logarithm of the post/baseline quotient. The non-significant PAS effects across studies and a wide range of responder rates between studies indicate a high variability of this method. We were thus not able to replicate findings from a previous meta-analysis showing robust effects of PAS. No pattern emerged regarding acquisition parameters that at this point could guide future studies to reduce variability and help increase response rate. For future studies, we propose to report the responder rate and recommend the use of the logarithmized post/baseline quotient for further analyses to better address the possibility that results are driven by few extreme cases

Beyond Triplet: Unconventional Superconductivity in a Spin-3/2 Topological Semimetal

In all known fermionic superfluids, Cooper pairs are composed of spin-1/2 quasi-particles that pair to form either spin-singlet or spin-triplet bound States. The spin of a Bloch electron, however, is fixed by the symmetries of the crystal and the atomic orbitals from which it is derived and, in some cases, can behave as if it were a spin-3/2 particle. The superconducting state of such a system allows pairing beyond spin-triplet, with higher spin quasi-particles combining to form quintet or septet pairs. We report evidence of unconventional superconductivity emerging from a spin-3/2 quasi-particle electronic structure in the half-Heusler semimetal YPtBi, a low-carrier density noncentrosymmetric cubic material with a high symmetry that preserves the p-like j = 3/2 manifold in the Bi-based Γ8 band in the presence of strong spin-orbit coupling. With a striking linear temperature dependence of the London penetration depth, the existence of line nodes in the superconducting order parameter Δ is directly explained by a mixed-parity Cooper pairing model with high total angular momentum, consistent with a high-spin fermionic superfluid state. We propose a k·p model of the j = 3/2 fermions to explain how a dominant J = 3 septet pairing state is the simplest solution that naturally produces nodes in the mixed even-odd parity gap. Together with the underlying topologically nontrivial band structure, the unconventional pairing in this system represents a truly novel form of superfluidity that has strong potential for leading the development of a new series of topological superconductors

Templated assembly of pore-forming peptides in lipid membranes

Pore-forming peptides are of interest due to their antimicrobial activity and ability to form gateways through lipid membranes. Chemical modification of these peptides makes it possible to arrange several peptide monomers into well-defined pore-forming structures using various templating strategies. These templated super-structures can exert antimicrobial activity at significantly lower total peptide concentration than their untemplated equivalents. In addition, the chemical moieties used for templating may be functionalized to interact specifically with targeted membranes such as those of pathogens or cancer cells. A range of molecular templates has been explored, including dimerization of pore-forming monomers, their covalent attachment to cyclodextrin, porphyrin or fullerene scaffolds as well as attachment of amino acid linkers or nucleic acid constructs to generate assemblies of 4 to 26 peptides or proteins. Compared to free peptide monomers, templated pore assemblies showed increased membrane affinity, prolonged open-state lifetimes of the pores and more frequent pore formation due to higher local concentration. These constructs are useful model systems for biophysical studies to understand porin and ion channel proteins and their mechanisms of insertion into lipid membranes. Recently designed DNA- templates are expanding the usefulness of templated pore assemblies beyond applications of cell killing and may include targeted drug delivery and accelerate the emerging field of single-molecule detection and characterization of biomolecules by nanopore-based resistive pulse sensing

Consumers\u27 Misunderstanding of Health Insurance.

We report results from two surveys of representative samples of Americans with private health insurance. The first examines how well Americans understand, and believe they understand, traditional health insurance coverage. The second examines whether those insured under a simplified all-copay insurance plan will be more likely to engage in cost-reducing behaviors relative to those insured under a traditional plan with deductibles and coinsurance, and measures consumer preferences between the two plans. The surveys provide strong evidence that consumers do not understand traditional plans and would better understand a simplified plan, but weaker evidence that a simplified plan would have strong appeal to consumers or change their healthcare choices

A bio-inspired amplification cascade for the detection of rare cancer cells

The main cause of cancer-related death is due to cancer cell spreading and formation of secondary tumors in distant organs, the so-called metastases. Metastatic cancer cells are detectable in the blood of cancer patients as circulating tumor cells (CTC) and may be exploited for prognostic and monitoring purposes, including in breast cancer. Due to their very low frequency, however, their quantitative detection remains a challenge in clinical practice. Nature has developed mechanisms to amplify rare biological events or weak signals, such as intracellular signaling pathways, cytokine networks or the coagulation cascades. At the National Center for Competence in Research (NCCR) in Bio-Inspired Materials we are coupling gold nanoparticle-based strategies with fibrinogen and DNA bio-inspired amplification cascades to develop an in vitro test to specifically and sensitively detect CTCs in patients' blood. In this article, we describe the biological context, the concept of bio-inspired amplification, and the approaches chosen. We also discuss limitations, open questions and further potential biomedical applications of such an approach

Quantifying annual spatial consistency in chick-rearing seabirds to inform important site identification

Animal tracking has afforded insights into patterns of space use in numerous species and thereby informed area-based conservation planning. A crucial consideration when estimating spatial distributions from tracking data is whether the sample of tracked animals is representative of the wider population. However, it may also be important to track animals in multiple years to capture changes in distribution in response to varying environmental conditions. Using GPS-tracking data from 23 seabird species, we assessed the importance of multi-year sampling for identifying important sites for conservation during the chick-rearing period, when seabirds are most spatially constrained. We found a high degree of spatial overlap among distributions from different years in most species. Multi-year sampling often captured a significantly higher portion of reference distributions (based on all data for a population) than sampling in a single year. However, we estimated that data from a single year would on average miss only 5 % less of the full distribution of a population compared to equal-sized samples collected across three years (min: −0.3 %, max: 17.7 %, n = 23). Our results suggest a key consideration for identifying important sites from tracking data is whether enough individuals were tracked to provide a representative estimate of the population distribution during the sampling period, rather than that tracking necessarily take place in multiple years. By providing an unprecedented multi-species perspective on annual spatial consistency, this work has relevance for the application of tracking data to informing the conservation of seabirds