Photon counting compressive depth mapping

We demonstrate a compressed sensing, photon counting lidar system based on the single-pixel camera. Our technique recovers both depth and intensity maps from a single under-sampled set of incoherent, linear projections of a scene of interest at ultra-low light levels around 0.5 picowatts. Only two-dimensional reconstructions are required to image a three-dimensional scene. We demonstrate intensity imaging and depth mapping at 256 x 256 pixel transverse resolution with acquisition times as short as 3 seconds. We also show novelty filtering, reconstructing only the difference between two instances of a scene. Finally, we acquire 32 x 32 pixel real-time video for three-dimensional object tracking at 14 frames-per-second.Comment: 16 pages, 8 figure

Expression of early nodulin genes in alfalfa mycorrhizae indicates that signal transduction pathways used in forming arbuscular mycorrhizae and Rhizobium-induced nodules may be conserved

Transcripts for two genes expressed early in alfalfa nodule development (MsENOD40 and MsENOD2) are found in mycorrhizal roots, but not in noncolonized roots or in roots infected with the fungal pathogen Rhizoctonia solani. These same two early nodulin genes are expressed in uninoculated roots upon application of the cytokinin 6-benzylaminopurine. Correlated with the expression of the two early nodulin genes, we found that mycorrhizal roots contain higher levels of trans-zeatin riboside than nonmycorrhizal roots. These data suggest that there may be conservation of signal transduction pathways between the two symbioses-nitrogen-fixing nodules and phosphate-acquiring mycorrhizae

Monotone Retracts and Some Characterizations of Dendrites

Let M be a metric continuum containing a fixed point p. The following conditions are shown to be equivalent. (i) M is a dendrite. (ii) Each subcontinuum of M is a monotone retract of M. (iii) M is arcwise connected and each subcontinuum of M containing p is a monotone retract of M

Dopamine and Risk Preferences in Different Domains

Individuals differ significantly in their willingness to take risks. Such differences may stem, at least in part, from individual biological (genetic) differences. We explore how risk-taking behavior correlates with different versions of the dopamine receptor D4 gene (DRD4), which has been implicated in previous studies of risk taking. We investigate risk taking in three contexts: economic risk taking as proxied by a financial gamble, self-reported general risk taking, and self-reported behavior in risk-related activities. Our participants are serious tournament bridge players with substantial experience in risk taking. Presumably, this sample is much less varied in its environment than a random sample of the population, making genetic based differences easier to detect. A prior study (Dreber et al. 2010) looked at risk taking by these individuals in their bridge decisions. Here we examine the riskiness of decisions they take in other contexts. We find evidence that individuals with a 7-repeat allele (7R+) of DRD4 take significantly more economic risk in an investment game than individuals without this allele (7R-). Interestingly, this positive relationship is driven by the men in our study, while the women show a negative but non-significant result. Even though the number of 7R+ women in our sample is low, our results may indicate a gender difference in how the 7R+ genotype affects behavior, a possibility that merits further study. Considering other risk measures, we find no difference between 7R+ and 7R- individuals in general risk taking or any of the risk-related activities. Overall, our results indicate that the dopamine system plays an important role in explaining individual differences in economic risk taking in men, but not necessarily in other activities involving risk.Risk preferences; Dopamine; Risk taking; Risk perception; DRD4

The Dopamine Receptor D4 Gene (DRD4) and Self-Reported Risk Taking in the Economic Domain

Recent evidence suggests that individual variation in risk taking is partly due to genetic factors. We explore how self-reported risk taking in different domains correlates with variation in the dopamine receptor D4 gene (DRD4). Past studies conflict on the influence of DRD4 in relation to risk taking. A sample of 237 serious tournament contract bridge players, experts on risk taking in one domain, was genotyped for having a 7-repeat allele (7R+) or not (7R-) at RD4. No difference was found between 7R+ and 7R- individuals in general risk taking or in several other risk-related activities.

Dopamine and Risk Preferences in Different Domains

Individuals differ significantly in their willingness to take risks. Such differences may stem, at least in part, from individual biological (genetic) differences. We explore how risk-taking behavior varies with different versions of the dopamine receptor D4 gene (DRD4), which has been implicated in previous studies of risk taking. We investigate risk taking in three contexts: economic risk taking as proxied by a financial gamble, self-reported general risk taking, and self-reported behavior in risk-related activities. Our participants are serious tournament bridge players with substantial experience in risk taking. Presumably, this sample is much less varied in its environment than a random sample of the population, making genetic-related differences easier to detect. A prior study (Dreber et al. 2010) looked at risk taking by these individuals in their bridge decisions. We examine their risk decisions in other contexts. We find evidence that individuals with a 7-repeat allele (7R+) of the DRD4 genetic polymorphism take significantly more economic risk in an investment game than individuals without this allele (7R-). Interestingly, this positive relationship is driven by the men in our study, while the women show a negative but non-significant result. Even though the number of 7R+ women in our sample is low, our results may indicate a gender difference in how the 7R+ genotype affects behavior, a possibility that merits further study. Considering other risk measures, we find no difference between 7R+ and 7R- individuals in general risk taking or any of the risk-related activities. Overall, our results indicate that the dopamine system plays an important role in explaining individual differences in economic risk taking in men, but not necessarily in other activities involving risk.

Virus Propagation in Multiple Profile Networks

Suppose we have a virus or one competing idea/product that propagates over a multiple profile (e.g., social) network. Can we predict what proportion of the network will actually get "infected" (e.g., spread the idea or buy the competing product), when the nodes of the network appear to have different sensitivity based on their profile? For example, if there are two profiles $\mathcal{A}$ and $\mathcal{B}$ in a network and the nodes of profile $\mathcal{A}$ and profile $\mathcal{B}$ are susceptible to a highly spreading virus with probabilities $\beta_{\mathcal{A}}$ and $\beta_{\mathcal{B}}$ respectively, what percentage of both profiles will actually get infected from the virus at the end? To reverse the question, what are the necessary conditions so that a predefined percentage of the network is infected? We assume that nodes of different profiles can infect one another and we prove that under realistic conditions, apart from the weak profile (great sensitivity), the stronger profile (low sensitivity) will get infected as well. First, we focus on cliques with the goal to provide exact theoretical results as well as to get some intuition as to how a virus affects such a multiple profile network. Then, we move to the theoretical analysis of arbitrary networks. We provide bounds on certain properties of the network based on the probabilities of infection of each node in it when it reaches the steady state. Finally, we provide extensive experimental results that verify our theoretical results and at the same time provide more insight on the problem

Arc-Smooth Continua

Continua admitting arc-structures and arc-smooth continua are introduced as higher dimensional analogues of dendroids and smooth dendroids, respectively. These continua include such spaces as: cones over compacta, convex continua in l2, strongly convex metric continua, injectively metrizable continua, as well as various topological semigroups, partially ordered spaces, and hyperspaces. The arc-smooth continua are shown to coincide with the freely contractible continua and with the metric K-spaces of Stadtlander. Known characterizations of smoothness in dendroids involving closed partial orders, the set function T, radially convex metrics, continuous selections, and order preserving mappings are extended to the setting of continua with arc-structures. Various consequences of the special contractibility properties of arc-smooth continua are also obtained

Assortative human pair-bonding for partner ancestry and allelic variation of the dopamine receptor D4 (DRD4) gene

The 7R allele of the dopamine receptor D4 gene has been associated with attention-deficit hyperactivity disorder and risk taking. On the cross-population scale, 7R allele frequencies have been shown to be higher in populations with more of a history of long-term migrations. It has also been shown that the 7R allele is associated with individuals having multiple-ancestries. Here we conduct a replication of this latter finding with two independent samples. Measures of subjects’ ancestry are used to examine past reproductive bonds. The individuals’ history of inter-racial/ancestral dating and their feelings about this are also assessed. Tentative support for an association between multiple ancestries and the 7R allele were found. These results are dependent upon the method of questioning subjects about their ancestries. Inter-racial dating and feelings about inter-racial pairing were not related to the presence of the 7R allele. This might be accounted for by secular trends that might have substantively altered the decision-making process employed when considering relationships with individuals from different groups. This study provides continued support for the 7R allele playing a role in migration and/or mate choice patterns. However, replications and extensions of this study are needed and must carefully consider how ancestry/race is assessed