Public Policy, entrepreneurship, and venture capital in the United States

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Historical biogeography and ecological niche modelling of the Asimina-Disepalum clade (Annonaceae): role of ecological differentiation in Neotropical-Asian disjunctions and diversification in Asia

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Optic flow information influencing heading perception during rotation

Poster Session - Perception and Action: abstract no. 22.34We investigated what roles global spatial frequency, surface structure, and foreground motion play in heading perception during simulated rotation from optic flow. The display …postprin

Phylogenetic Reconstruction, Morphological Diversification and Generic Delimitation of Disepalum (Annonaceae)

Taxonomic delimitation of Disepalum (Annonaceae) is contentious, with some researchers favoring a narrow circumscription following segregation of the genus Enicosanthellum. We reconstruct the phylogeny of Disepalum and related taxa based on four chloroplast and two nuclear DNA regions as a framework for clarifying taxonomic delimitation and assessing evolutionary transitions in key morphological characters. Maximum parsimony, maximum likelihood and Bayesian methods resulted in a consistent, well-resolved and strongly supported topology. Disepalum s.l. is monophyletic and strongly supported, with Disepalum s. str. and Enicosanthellum retrieved as sister groups. Although this topology is consistent with both taxonomic delimitations, the distribution of morphological synapomorphies provides greater support for the inclusion of Enicosanthellum within Disepalum s.l. We propose a novel infrageneric classification with two subgenera. Subgen. Disepalum (= Disepalum s. str.) is supported by numerous synapomorphies, including the reduction of the calyx to two sepals and connation of petals. Subgen. Enicosanthellum lacks obvious morphological synapomorphies, but possesses several diagnostic characters (symplesiomorphies), including a trimerous calyx and free petals in two whorls. We evaluate changes in petal morphology in relation to hypotheses of the genetic control of floral development and suggest that the compression of two petal whorls into one and the associated fusion of contiguous petals may be associated with the loss of the pollination chamber, which in turn may be associated with a shift in primary pollinator. We also suggest that the formation of pollen octads may be selectively advantageous when pollinator visits are infrequent, although this would only be applicable if multiple ovules could be fertilized by each octad; since the flowers are apocarpous, this would require an extragynoecial compitum to enable intercarpellary growth of pollen tubes. We furthermore infer that the monocarp fruit stalks are likely to have evolved independently from those in other Annonaceae genera and may facilitate effective dispersal by providing a color contrast within the fruit.published_or_final_versio

Historical biogeography of Asimina-Disepalum (Annonaceae): origins of tropical intercontinental disjunctions and diversifications in Southeast Asia

Oral Session: Secondary forestsStudies of tropical intercontinental disjunctions, common biogeographical patterns in flowering plants, enable insights into the origin of extant distributions and diversity patterns. We investigate the temporal origin of the Neotropical-Asian disjunction in the Asimina-Disepalum clade of the early-divergent angiosperm family Annonaceae, and temporal congruence with underlying palaeoclimatic and geological processes. Moreover, we aim to identify the geographical origin of Disepalum, and to infer dispersal and vicariance events as well as potentially correlated climate niche differentiation in the evolution of the genus in …postprin

Disentangling the effects of object position and motion on heading judgments in the presence of a moving object

Tuesday Morning Posters - Motion Perception: Optic flow and heading: no. 53.4026Previous research has found that moving objects bias heading perception only when they occlude the focus of expansion (FOE) in the background optic flow, with the direction of bias depending on whether the moving object was approached or at a fixed distance from the moving observer. However, the effect of object motion on heading perception was confounded with object position in previous studies. Here, we disentangled the contributions of object motion and position to heading bias. In each 1s trial, the display simulated forward observer motion at 1 m/s through a ...postprin

Inkjet printed multimetal microelectrodes on PDMS for functionalized microfluidic systems

A novel direct method of metal microelectrode patterning on polydimethylsiloxane (PDMS) using inkjet printed gold and silver nanoparticles to form electrochemical sensors is presented. Inkjet printing is an additive microfabrication technique enabling microelectrode patterning directly over large areas at low-temperatures. (3-mercaptopropyl) trimethoxysilane (MPTMS) to promote PDMS surface wettability and improve metal adhesion and a pixel-printing subsampling method to overcome surface tension driven ink-droplet coalescence, are then employed to form a robust fabrication process. The resulting printed gold and silver microelectrodes exhibit good compactness, continuity and conductivity, and are used to manufacture functionalized microfluidic systems with in-situ three-electrode electrochemical sensors.published_or_final_versio

Two-photon excited photoluminescence in InGaN multi-quantum-wells structures

In this work, we report on the two-photon absorption induced luminescence of InGaN multiple quantum wells grown on sapphire. When the sample was excited by femtosecond near-infrared laser pulses at room temperature, an intense luminescence signal peaked at ∼415 nm from the sample was observed, which indicates strong nonlinear optical effect in InGaN quantum well structures. The interferometric autocorrelated luminescence traces were recorded to verify the second order nonlinearity of the luminescence. In addition, the strong second harmonic generation signal of the excitation laser was also observed. The mechanism of the two-photon excited photoluminescence in InGaN quantum wells was discussed.published_or_final_versionpublished_or_final_versio

Comprehensive Characterization of the Transmitted/Founder env Genes From a Single MSM Cohort in China

Background: The men having sex with men (MSM) population has become one of the major risk groups for HIV-1 infection in China. However, the epidemiological patterns, function of the env genes, and autologous and heterologous neutralization activity in the same MSM population have not been systematically characterized. Methods: The env gene sequences were obtained by the single genome amplification. The time to the most recent common ancestor was estimated for each genotype using the Bayesian Markov Chain Monte Carlo approach. Coreceptor usage was determined in NP-2 cells. Neutralization was analyzed using Env pseudoviruses in TZM-bl cells. Results: We have obtained 547 full-length env gene sequences by single genome amplification from 30 acute/early HIV-1–infected individuals in the Beijing MSM cohort. Three genotypes (subtype B, CRF01_AE, and CRF07_BC) were identified and 20% of the individuals were infected with multiple transmitted/founder (T/F) viruses. The tight clusters of the MSM sequences regardless of geographic origins indicated nearly exclusive transmission within the MSM population and limited number of introductions. The time to the most recent common ancestor for each genotype was 10–15 years after each was first introduced in China. Disparate preferences for coreceptor usages among 3 genotypes might lead to the changes in percentage of different genotypes in the MSM population over time. The genotype-matched and genotype-mismatched neutralization activity varied among the 3 genotypes. Conclusions: The identification of unique characteristics for transmission, coreceptor usage, neutralization profile, and epidemic patterns of HIV-1 is critical for the better understanding of transmission mechanisms, development of preventive strategies, and evaluation of vaccine efficacy in the MSM population in China