Inversely Unstable Solutions of Two-Dimensional Systems on Genus-p Surfaces and the Topology of Knotted Attractors

In this paper, we will show that a periodic nonlinear, time-varying dissipative system that is defined on a genus-p surface contains one or more invariant sets which act as attractors. Moreover, we shall generalize a result in [Martins, 2004] and give conditions under which these invariant sets are not homeomorphic to a circle individually, which implies the existence of chaotic behaviour. This is achieved by studying the appearance of inversely unstable solutions within each invariant set.Comment: 19 pages with 20 figures, AMS La-TeX, to be published in International Journal of Bifurcation and Chao

At risk of being risky: The relationship between "brain age" under emotional states and risk preference.

Developmental differences regarding decision making are often reported in the absence of emotional stimuli and without context, failing to explain why some individuals are more likely to have a greater inclination toward risk. The current study (N=212; 10-25y) examined the influence of emotional context on underlying functional brain connectivity over development and its impact on risk preference. Using functional imaging data in a neutral brain-state we first identify the "brain age" of a given individual then validate it with an independent measure of cortical thickness. We then show, on average, that "brain age" across the group during the teen years has the propensity to look younger in emotional contexts. Further, we show this phenotype (i.e. a younger brain age in emotional contexts) relates to a group mean difference in risk perception - a pattern exemplified greatest in young-adults (ages 18-21). The results are suggestive of a specified functional brain phenotype that relates to being at "risk to be risky.

Precision atomic gravimeter based on Bragg diffraction

We present a precision gravimeter based on coherent Bragg diffraction of freely falling cold atoms. Traditionally, atomic gravimeters have used stimulated Raman transitions to separate clouds in momentum space by driving transitions between two internal atomic states. Bragg interferometers utilize only a single internal state, and can therefore be less susceptible to environmental perturbations. Here we show that atoms extracted from a magneto-optical trap using an accelerating optical lattice are a suitable source for a Bragg atom interferometer, allowing efficient beamsplitting and subsequent separation of momentum states for detection. Despite the inherently multi-state nature of atom diffraction, we are able to build a Mach-Zehnder interferometer using Bragg scattering which achieves a sensitivity to the gravitational acceleration of $\Delta g/g = 2.7\times10^{-9}$ with an integration time of 1000s. The device can also be converted to a gravity gradiometer by a simple modification of the light pulse sequence.Comment: 13 pages, 11 figure

Cardiac afferent activity modulates the expression of racial stereotypes

Negative racial stereotypes tend to associate Black people with threat. This often leads to the misidentification of harmless objects as weapons held by a Black individual. Yet, little is known about how bodily states impact the expression of racial stereotyping. By tapping into the phasic activation of arterial baroreceptors, known to be associated with changes in the neural processing of fearful stimuli, we show activation of race-threat stereotypes synchronized with the cardiovascular cycle. Across two established tasks, stimuli depicting Black or White individuals were presented to coincide with either the cardiac systole or diastole. Results show increased race-driven misidentification of weapons during systole, when baroreceptor afferent firing is maximal, relative to diastole. Importantly, a third study examining the positive Black-athletic stereotypical association fails to demonstrate similar modulations by cardiac cycle. We identify a body–brain interaction wherein interoceptive cues can modulate threat appraisal and racially biased behaviour in context-dependent ways

Law and Neuroscience: Recommendations Submitted to the President\u27s Bioethics Commission

President Obama charged the Presidential Commission for the Study of Bioethical Issues to identify a set of core ethical standards in the neuroscience domain, including the appropriate use of neuroscience in the criminal-justice system. The Commission, in turn, called for comments and recommendations. The MacArthur Foundation Research Network on Law and Neuroscience submitted a consensus statement, published here, containing 16 specific recommendations. These are organized within three main themes: 1) what steps should be taken to enhance the capacity of the criminal justice system to make sound decisions regarding the admissibility and weight of neuroscientific evidence?; 2) to what extent can the capacity of neurotechnologies to aid in the administration of criminal justice be enhanced through research?; and 3) in what additional ways might important ethical issues at the intersection of neuroscience and criminal justice be addressed

Law and Neuroscience: Recommendations Submitted to the President\u27s Bioethics Commission

President Obama charged the Presidential Commission for the Study of Bioethical Issues to identify a set of core ethical standards in the neuroscience domain, including the appropriate use of neuroscience in the criminal-justice system. The Commission, in turn, called for comments and recommendations. The MacArthur Foundation Research Network on Law and Neuroscience submitted a consensus statement, published here, containing 16 specific recommendations. These are organized within three main themes: 1) what steps should be taken to enhance the capacity of the criminal justice system to make sound decisions regarding the admissibility and weight of neuroscientific evidence?; 2) to what extent can the capacity of neurotechnologies to aid in the administration of criminal justice be enhanced through research?; and 3) in what additional ways might important ethical issues at the intersection of neuroscience and criminal justice be addressed

G2i Knowledge Brief: A Knowledge Brief of the MacArthur Foundation Research Network on Law and Neuroscience

Courts are daily confronted with admissibility issues – such as in cases involving neuroscientific testimony – that sometimes involve both the existence of a general phenomenon (i.e., “G”) and the question of whether a particular case represents a specific instance of that general phenomenon (i.e., “i”). Unfortunately, courts have yet to carefully consider the implications of “G2i” for their admissibility decisions. In some areas, courts limit an expert’s testimony to the general phenomenon. They insist that whether the case at hand is an instance of that phenomenon is exclusively a jury question, and thus not an appropriate subject of expert opinion. In other cases, in contrast, courts hold that expert evidence must be provided on both the group-data issue (i.e., that the phenomenon exists) and what is called the “diagnostic” issue (i.e., that this case is an instance of that phenomenon). Consequently, the MacArthur Foundation Research Network on Law and Neuroscience has prepared this knowledge brief to help courts manage the G2i divide. Specifically, we recommend that courts first determine whether proffered expert testimony concerns only the existence of the general phenomenon or instead concerns both that and the diagnosis that a particular case represents an instance of that phenomenon. Only after making that determination should the court make its admissibility decision (guided, for instance, by the Daubert factors for admitting scientific evidence)

The Cortisol Response to Anticipated Intergroup Interactions Predicts Self-Reported Prejudice

Objectives: While prejudice has often been shown to be rooted in experiences of threat, the biological underpinnings of this threat–prejudice association have received less research attention. The present experiment aims to test whether activations of the hypothalamus-pituitary-adrenal (HPA) axis, due to anticipated interactions with out-group members, predict self-reported prejudice. Moreover, we explore potential moderators of this relationship (i.e., interpersonal similarity; subtle vs. blatant prejudice). Methodology/Principal findings: Participants anticipated an interaction with an out-group member who was similar or dissimilar to the self. To index HPA activation, cortisol responses to this event were measured. Then, subtle and blatant prejudices were measured via questionnaires. Findings indicated that only when people anticipated an interaction with an out-group member who was dissimilar to the self, their cortisol response to this event significantly predicted subtle (r =.50) and blatant (r =.53) prejudice. Conclusions: These findings indicate that prejudicial attitudes are linked to HPA-axis activity. Furthermore, when intergroup interactions are interpreted to be about individuals (and not so much about groups), experienced threat (or its biological substrate) is less likely to relate to prejudice. This conclusion is discussed in terms of recent insights from social neuroscience

A New Euler's Formula for DNA Polyhedra

DNA polyhedra are cage-like architectures based on interlocked and interlinked DNA strands. We propose a formula which unites the basic features of these entangled structures. It is based on the transformation of the DNA polyhedral links into Seifert surfaces, which removes all knots. The numbers of components , of crossings , and of Seifert circles are related by a simple and elegant formula: . This formula connects the topological aspects of the DNA cage to the Euler characteristic of the underlying polyhedron. It implies that Seifert circles can be used as effective topological indices to describe polyhedral links. Our study demonstrates that, the new Euler's formula provides a theoretical framework for the stereo-chemistry of DNA polyhedra, which can characterize enzymatic transformations of DNA and be used to characterize and design novel cages with higher genus