A synoptic view of solar transient evolution in the inner heliosphere using the Heliospheric Imagers on STEREO

By exploiting data from the STEREO/heliospheric imagers (HI) we extend a well-established technique developed for coronal analysis by producing time-elongation plots that reveal the nature of solar transient activity over a far more extensive region of the heliosphere than previously possible from coronagraph images. Despite the simplicity of these plots, their power in demonstrating how the plethora of ascending coronal features observed near the Sun evolve as they move antisunward is obvious. The time-elongation profile of a transient tracked by HI can, moreover, be used to establish its angle out of the plane-of-the-sky; an illustration of such analysis reveals coronal mass ejection material that can be clearly observed propagating out to distances beyond 1AU. This work confirms the value of the time-elongation format in identifying/characterising transient activity in the inner heliosphere, whilst also validating the ability of HI to continuously monitor solar ejecta out to and beyond 1A

The k-j-j′ vector correlation in inelastic and reactive scattering

Quasi-classical trajectory (QCT) methods are presented which allow characterization of the angular momentum depolarization of the products of inelastic and reactive scattering. The particular emphasis of the theory is on three-vector correlations, and on the connection with the two-vector correlation between the initial and final angular momenta, j and j′, which is amenable to experimental measurement. The formal classical theory is presented, and computational results for NO(A) + He are used to illustrate the type of mechanistic information provided by analysis of the two- and three-vector correlations. The classical j-j′ two-vector correlation results are compared with quantum mechanical calculations, and are shown to be in good agreement. The data for NO(A) + He support previous conclusions [M. Brouard, H. Chadwick, Y.-P. Chang, R. Cireasa, C. J. Eyles, A. O. L. Via, N. Screen, F. J. Aoiz, and J. Kos, J. Chem. Phys. 131, 104307 (2009)]10.1063/1.3212608 that this system is only weakly depolarizing. Furthermore, it is shown that the projection of j along the kinematic apse is nearly conserved for this system under thermal collision energy conditions. © 2011 American Institute of Physics

Explaining science: integrating science literacy into a research-based undergraduate program

Science literacy, which we define as the writing, reading and information research skills required to practice science, is a central component of the Integrated Science Program (iSci) at McMaster University. Concepts developed in the interactive, collaboratively-taught science literacy classes support the research projects that form the basis of learning in iSci. The aim of the science literacy component is to prepare the next generation of professional scientists to communicate not only within academia, but also to the wider community. In this presentation, we will describe the format of iSci and the role of science literacy within it. We shall then discuss the various activities and techniques used to introduce professional skills throughout the four-year program. iSci students gain experience in writing for audiences through two main conduits. One is a science blog: an on-going, individual, low-stakes writing practice activity. The other is a series of research project assessed deliverables: high-stakes, collaborative writing tasks. These take the form of oral presentations, posters, debates, abstracts, lab reports, and papers. Students are supported in developing writing skills (from research notes, through drafting, review, and editing) by feedback from instructors, dedicated TAs, and their peers. Information literacy skills, including source evaluation and information retrieval, are developed from the start of the Program. iSci has strong links to the University Library and students are introduced to primary literature early in the course. We report on results from the first two years of the science literacy initiative, and outline plans for further developments and evaluations

Collisional angular momentum depolarization of OH(A) and NO(A) by Ar: A comparison of mechanisms

This paper discusses the contrasting mechanisms of collisional angular momentum depolarization of OH(A(2)Σ(+)) and NO(A(2)Σ(+)) by Ar. New experimental results are presented for the collisional depolarization of OH(A) + Ar under both thermal and superthermal collision conditions, including cross sections for loss of both angular momentum orientation and alignment. Previous work on the two systems is summarized. It is shown that NO(A) + Ar depolarization is dominated by impulsive events in which the projection of the angular momentum, j, along the kinematic apse, a, is nearly conserved, and in which the majority of the trajectories can be described as "nearside." By contrast, at the relatively low collision energies sampled at 300 K, OH(A) + Ar depolarization is dominated by attractive collisions, which show a preponderance of "farside" trajectories. There is also evidence for very long-lived, complex type trajectories in which OH(A) and Ar orbit each other for several rotational periods prior to separation. Nevertheless, there is still a clear preference for conservation of the projection of j along the kinematic apse for both elastic and inelastic collisions. Experimental and theoretical results reveal that, as the collision energy is raised, the depolarization of OH(A) by Ar becomes more impulsive-like in nature

Ab Initio studies of the interaction potential for the Xe–NO(X 2Π) van der Waals complex: Bound states and fully quantum and quasi-classical scattering

Adiabatic potential energy surfaces for the ground electronic state of the Xe⋅⋅⋅NO(X(2)Π) van der Waals complex have been calculated using the spin-restricted coupled cluster method with single, double, and non-iterative triple excitations (RCCSD(T)). The scalar relativistic effects present in the Xe atom were included by an effective core potential and we extended the basis with bond functions to improve the description of the dispersion interaction. It has been found that the global minimum on the A(') adiabatic surface occurs at a T-shaped geometry with γ(e) = 94° and R(e) = 7.46 a(0), and with well depth of D(e) = 148.68 cm(-1). There is also an additional local minimum for the collinear geometry Xe-NO with a well depth of 104.5 cm(-1). The adiabat of A('') symmetry exhibits a single minimum at a distance R(e) = 7.68 a(0) and has a skewed geometry with γ(e) = 64° and a well depth of 148.23 cm(-1). Several C(nl) van der Waals dispersion coefficients are also estimated, of which C(6, 0) and C(6, 2) are in a reasonable agreement with previous theoretical results obtained by Nielson et al. [J. Chem. Phys. 64, 2055 (1976)]. The new potential energy surfaces were used to calculate bound states of the complex for total angular momentum quantum numbers up to J = 7/2. The ground state energy of Xe⋅⋅⋅NO(X(2)Π) is D(0) = 117 cm(-1), which matches the experimental value very accurately (within 3.3%). Scattering calculations of integral and differential cross sections have also been performed using fully quantum close coupling calculations and quasi-classical trajectory method at a collision energy of 63 meV. These calculations reveal the important role played by L-type rainbows in the scattering dynamics of the heavier Rg-NO(X) systems

Developmentally vitamin D-deficient rats show enhanced prepulse inhibition after acute δ9-tetrahydrocannabinol

Developmental vitamin D (DVD) deficiency has been proposed as a risk factor for schizophrenia. DVD-deficient rats show selective cognitive deficits and novelty-induced hyperlocomotion and enhanced locomotor responses from acute treatment with psychomimetic drugs, such as amphetamine and MK-801. Here we aimed to examine the effect of a drug from a different class of psychomimetic/psychoactive compounds, Δ-tetrahydrocannabinol (THC), on tasks of relevance to the cognitive and positive symptoms of schizophrenia. The aim of this study was to investigate whether DVD deficiency modulates the behavioural effects of THC on tests of delay-dependent memory, sensorimotor gating and locomotion. Adult control and DVD-deficient rats were injected with THC (0, 0.3, 0.6, 1.25, 2.5 mg/kg) 15 min before a delay match to sample (DMTS) task using variable delays (0-24 s). A separate group of rats was injected with either 2.5 mg/kg THC or vehicle before tests of either prepulse inhibition (PPI) of the acoustic startle response or in the open field. Control and DVD-deficient rats showed a similar dose-dependent impairment in performance on the DMTS. The greatest impairment was observed at 2.5 mg/kg for all delays (0-24 s). DVD-deficient rats showed THC-induced enhancement of PPI, which was not observed in control rats. There was no effect of maternal diet on acoustic startle response or locomotor responses in the open field. This study reports the novel findings that DVD-deficient rats were more sensitive to the acute effects of THC on PPI. It appears that prenatal vitamin D deficiency has long-term effects on sensitivity to the behavioural effects of cannabinoids

New Perspectives on Rodent Models of Advanced Paternal Age: Relevance to Autism

Offspring of older fathers have an increased risk of various adverse health outcomes, including autism and schizophrenia. With respect to biological mechanisms for this association, there are many more germline cell divisions in the life history of a sperm relative to that of an oocyte. This leads to more opportunities for copy error mutations in germ cells from older fathers. Evidence also suggests that epigenetic patterning in the sperm from older men is altered. Rodent models provide an experimental platform to examine the association between paternal age and brain development. Several rodent models of advanced paternal age (APA) have been published with relevance to intermediate phenotypes related to autism. All four published APA models vary in key features creating a lack of consistency with respect to behavioral phenotypes. A consideration of common phenotypes that emerge from these APA-related mouse models may be informative in the exploration of the molecular and neurobiological correlates of APA

Cognitive performance and response inhibition in developmentally vitamin D (DVD)-deficient rats

Evidence from epidemiological studies suggest that low levels of vitamin D during early life alter brain development and may increase the risk of various adverse health outcomes, including schizophrenia. The aim of this experiment was to examine the effect of developmental vitamin D (DVD) deficiency on attentional processing using the 5-choice serial reaction time task (5C-SRT) and the 5-choice continuous performance test (5C-CPT), which specifically assesses sustained attention and vigilance in rodents. DVD-deficient and control rats were exposed to a series of target and non-target trials within each operant testing session. A number of measures were recorded including hit, miss, false alarm and correct rejection, as well as premature and perseverative responses. Performance on 5C-CPT was also assessed after administration of the atypical antipsychotic, clozapine. The adult offspring of DVD-deficient rats had higher levels of impulsivity, as demonstrated by a significant increase in premature responses. On the 5C-SRT and target trials of the 5C-CPT, accuracy was not significantly affected by prenatal diet; however DVD-deficient rats made 50% fewer correct rejections compared to controls on non-target trials of the 5C-CPT. Thus, control rats were able to discriminate between target and non-target trials, whereas DVD-deficient rats were unable to make this discrimination. Clozapine reduced the occurrence of false alarms in DVD-deficient rats to a level comparable to control values. Taken together these data suggest DVD-deficient rats have increased impulsivity as well as a lack of inhibitory control, and these features may be informative in terms of modeling the cognitive deficits observed in schizophrenia