Electronics and Chemistry: Varying Single Molecule Junction Conductance Using Chemical Substituents

We measure the low bias conductance of a series of substituted benzene diamine molecules while breaking a gold point contact in a solution of the molecules. Transport through these substituted benzenes is by means of nonresonant tunneling or superexchange, with the molecular junction conductance depending on the alignment of the metal Fermi level to the closest molecular level. Electron-donating substituents, which drive the occupied molecular orbitals up, increase the junction conductance, while electron-withdrawing substituents have the opposite effect. Thus for the measured series, conductance varies inversely with the calculated ionization potential of the molecules. These results reveal that the occupied states are closest to the gold Fermi energy, indicating that the tunneling transport through these molecules is analogous to hole tunneling through an insulating film.Comment: 14 pages, 4 figure

Quantitative speech production profiles and focal left hemisphere lesion

The clinical differentiation between apraxia of speech (AOS) and aphasia with phonemic paraphasia is based on impressionistic consideration of a varying list of speech properties. The diagnosing clinician is challenged with determining the presence or absence of these disorders by considering the extent to which characteristic features are evident in the speech output and by determining how much relative weight to assign to each. Predictably, the subjective nature of the diagnostic process can translate to limited agreement, even among experienced clinicians (Haley, Jacks, de Riesthal, Abou-Khalil, & Roth, 2012), and the risks of misdiagnosis and diagnostic uncertainty are substantial (Wambaugh, 2006). Additionally it is likely that the adherence to a strictly dichotomous classification system overlooks theoretically and clinically important heterogeneity. The purpose of this study was to identify a preliminary set of speech production profiles based on naturally occurring variations in individuals with acquired focal brain lesions. To avoid classification circularity, assessments were conducted without consideration of clinical speech diagnosis, and metrics were selected to represent diverse and robust observations about speech properties associated with left hemisphere lesions

Quantum oscillations observed in graphene at microwave frequencies

We have measured the microwave conductance of mechanically exfoliated graphene at frequencies up to 8.5 GHz. The conductance at 4.2 K exhibits quantum oscillations, and is independent of the frequency

Summarizing and Comparing Story Plans

Branching story games have gained popularity for creating unique playing experiences by adapting story content in response to user actions. Research in interactive narrative (IN) uses automated planning to generate story plans for a given story problem. However, a story planner can generate multiple story plan solutions, all of which equally-satisfy the story problem definition but contain different story content. These differences in story content are key to understanding the story branches in a story problem\u27s solution space, however we lack narrative-theoretic metrics to compare story plans. We address this gap by first defining a story plan summarization model to capture the important story semantics from a story plan. Secondly, we define a story plan comparison metric that compares story plans based on the summarization model. Using the Glaive narrative planner and a simple story problem, we demonstrate the usefulness of using the summarization model and distance metric to characterize the different story branches in a story problem\u27s solution space

Control of Daily Transcript Oscillations in Drosophila by Light and the Circadian Clock

The transcriptional circuits of circadian clocks control physiological and behavioral rhythms. Light may affect such overt rhythms in two ways: (1) by entraining the clock circuits and (2) via clock-independent molecular pathways. In this study we examine the relationship between autonomous transcript oscillations and light-driven transcript responses. Transcript profiles of wild-type and arrhythmic mutant Drosophila were recorded both in the presence of an environmental photocycle and in constant darkness. Systematic autonomous oscillations in the 12- to 48-h period range were detectable only in wild-type flies and occurred preferentially at the circadian period length. However, an extensive program of light-driven expression was confirmed in arrhythmic mutant flies. Many light-responsive transcripts are preferentially expressed in the compound eyes and the phospholipase C component of phototransduction, NORPA (no receptor potential), is required for their light-dependent regulation. Although there is evidence for the existence of multiple molecular clock circuits in cyanobacteria, protists, plants, and fungi, Drosophila appears to possess only one such system. The sustained photic expression responses identified here are partially coupled to the circadian clock and may reflect a mechanism for flies to modulate functions such as visual sensitivity and synaptic transmission in response to seasonal changes in photoperiod

Whole genome data from Curtobacterium flaccumfaciens pv. flaccumfaciens strains associated with tan spot of mungbean and soybean reveal diverse plasmid profiles

Despite the substantial economic impact of Curtobacterium flaccumfaciens pv. flaccumfaciens (Cff) on legume productions worldwide, the genetic basis of its pathogenicity and potential host association is poorly understood. The production of high-quality reference genome assemblies of Cff strains associated with different hosts sheds light on the genetic basis of its pathogenic variability and host association. Moreover, the study of recent outbreaks of bacterial wilt and microevolution of the pathogen in Australia requires access to high-quality, reference genomes that are sufficiently closely related to the population being studied within Australia. We provide the first genome assemblies of Cff strains associated with mungbean and soybean, which revealed high variability in their plasmid composition. The analysis of Cff genomes revealed an extensive suite of carbohydrate-active enzymes potentially associated with pathogenicity, including four carbohydrate esterases, 50 glycoside hydrolases, 23 glycosyl transferases, and a polysaccharide lyase. We also identified 11 serine peptidases, three of which were located within a linear plasmid, pCff119. These high-quality assemblies and annotations will provide a foundation for population genomics studies of Cff in Australia and for answering fundamental questions regarding pathogenicity factors and adaptation of Cff to various hosts worldwide, and, at a broader scale, contribute to unravelling genomic features of Gram-positive, xylem-inhabiting bacterial pathogens

Being ethically minded: Practising the scholarship of teaching and learning in an ethical manner

This article was published as Being ethically minded: Practising the scholarship of teaching and learning in an ethical manner in Teaching and Learning Inquiry, 1(2), 2013, pp. 23-32. No part of this article may be reproduced, stored in a retrieval system, transmitted, or distributed, in any form, by any means, electronic, mechanical, photographic, or otherwise, without the prior permission of Indiana University Press. For educational re-use, please contact the Copyright Clearance Center (508-744-3350). For all other permissions, please visit Indiana University Press' permissions page.The authors propose a working definition of ethical SoTL, an ethical framework for SoTL inquiry, and present a case study that illustrates the complexity of ethical issues in SoTL. The Ethical SoTL Matrix is a flexible framework designed to support SoTL practitioners, particularly in the formative stages of their inquiries. Three dominant ethical traditions form the basis of the matrix: teleological or pragmatic, external, and deontological. The key message of the paper is that SoTL practitioners should reflect on different perspectives in their efforts to do what is right in any given situation. The matrix introduces three dominant ethical traditions, but SoTL practitioners may ultimately move beyond these traditions to explore a range of ethical considerations appropriate to their projects and disciplines