1,255 research outputs found

    Control of recollision wave packets for molecular orbital tomography using short laser pulses

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    The tomographic imaging of arbitrary molecular orbitals via high-order harmonic generation requires that electrons recollide from one direction only. Within a semi-classical model, we show that extremely short phase-stabilized laser pulses offer control over the momentum distribution of the returning electrons. By adjusting the carrier-envelope phase, recollisions can be forced to occur from mainly one side, while retaining a broad energy spectrum. The signatures of the semi-classical distributions are observed in harmonic spectra obtained by numerical solution of the time-dependent Schr\"{o}dinger equation.Comment: 8 pages, 4 figures; v2: Added some extra clarifications; v3: minor grammatical change

    Tracking Inflation on a Daily Basis

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    Using online data for prices and real-time debit card transaction data on changes in expenditures for Switzerland allows us to track inflation on a daily basis. While the daily price index fluctuates around the official price index in normal times, it drops immediately after the lockdown related to the COVID19 pandemic. Official statistics reflect this drop only with a lag, specifically because data collection takes time and is impeded by lockdown conditions. Such daily real-time information can be useful to gauge the relative importance of demand and supply shocks and thus inform policymakers who need to determine appropriate policy measures

    PRESERVICE TEACHERS’ PERCEPTIONS AND KNOWLEDGE OF RESPONSE TO INTERVENTION/MULTITIERED SYSTEMS OF SUPPORT

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    There has been considerable research that establishes the need to improve teachers’ knowledge of and ability to effectively implement response to intervention (RtI)/multi-tiered systems of support (MTSS), and there is a scarcity of research examining interventions addressing these concerns. In a mixed methods study, we examined the perceptions and knowledge of the RtI/MTSS frameworks of undergraduate preservice teaching candidates enrolled in a dual certification program at a small, private Catholic university in Kentucky, before and after participating in a semester-long, experiential learning project. The project involved monitoring both the reading and mathematics progress of struggling elementary or middle school-aged students using validated Curriculum Based Measures. Preservice teachers worked in concert with the cooperating classroom teacher and their professor to score, graph, and interpret CBM results and make recommendations for high-quality, research-based intervention. Results from participants indicate their concern that not all teachers will enter the profession with knowledge of RtI/MTSS. Further, the experiential learning project intervention enhanced preservice teachers’ perceptions and knowledge of RtI/MTSS frameworks

    Semiclassical two-step model for strong-field ionization

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    We present a semiclassical two-step model for strong-field ionization that accounts for path interferences of tunnel-ionized electrons in the ionic potential beyond perturbation theory. Within the framework of a classical trajectory Monte-Carlo representation of the phase-space dynamics, the model employs the semiclassical approximation to the phase of the full quantum propagator in the exit channel. By comparison with the exact numerical solution of the time-dependent Schr\"odinger equation for strong-field ionization of hydrogen, we show that for suitable choices of the momentum distribution after the first tunneling step, the model yields good quantitative agreement with the full quantum simulation. The two-dimensional photoelectron momentum distributions, the energy spectra, and the angular distributions are found to be in good agreement with the corresponding quantum results. Specifically, the model quantitatively reproduces the fan-like interference patterns in the low-energy part of the two-dimensional momentum distributions as well as the modulations in the photoelectron angular distributions.Comment: 31 pages, 7 figure

    Functional identification of an aggression locus in the mouse hypothalamus

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    Electrical stimulation of certain hypothalamic regions in cats and rodents can elicit attack behaviour, but the exact location of relevant cells within these regions, their requirement for naturally occurring aggression and their relationship to mating circuits have not been clear. Genetic methods for neural circuit manipulation in mice provide a potentially powerful approach to this problem, but brain-stimulation-evoked aggression has never been demonstrated in this species. Here we show that optogenetic, but not electrical, stimulation of neurons in the ventromedial hypothalamus, ventrolateral subdivision (VMHvl) causes male mice to attack both females and inanimate objects, as well as males. Pharmacogenetic silencing of VMHvl reversibly inhibits inter-male aggression. Immediate early gene analysis and single unit recordings from VMHvl during social interactions reveal overlapping but distinct neuronal subpopulations involved in fighting and mating. Neurons activated during attack are inhibited during mating, suggesting a potential neural substrate for competition between these opponent social behaviours

    Spatiotemporal dynamics of the postnatal developing primate brain transcriptome.

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    Developmental changes in the temporal and spatial regulation of gene expression drive the emergence of normal mature brain function, while disruptions in these processes underlie many neurodevelopmental abnormalities. To solidify our foundational knowledge of such changes in a primate brain with an extended period of postnatal maturation like in human, we investigated the whole-genome transcriptional profiles of rhesus monkey brains from birth to adulthood. We found that gene expression dynamics are largest from birth through infancy, after which gene expression profiles transition to a relatively stable state by young adulthood. Biological pathway enrichment analysis revealed that genes more highly expressed at birth are associated with cell adhesion and neuron differentiation, while genes more highly expressed in juveniles and adults are associated with cell death. Neocortex showed significantly greater differential expression over time than subcortical structures, and this trend likely reflects the protracted postnatal development of the cortex. Using network analysis, we identified 27 co-expression modules containing genes with highly correlated expression patterns that are associated with specific brain regions, ages or both. In particular, one module with high expression in neonatal cortex and striatum that decreases during infancy and juvenile development was significantly enriched for autism spectrum disorder (ASD)-related genes. This network was enriched for genes associated with axon guidance and interneuron differentiation, consistent with a disruption in the formation of functional cortical circuitry in ASD

    Beaten into Submissiveness? An Investigation into the Protective Strategies used by Survivors of Domestic Abuse

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    This is a pre-copyedited, author-produced pdf of an article accepted for publication in Journal of Interpersonal Violence following peer review. Laura Irving & Ben Chi-pun Liu, 'Beaten into Submissiveness? An investigation Into the Protective Strategies Used by Survivors of Domestic Abuse', Journal of Interpersonal Violence, first published online 14 December 2016, available online at doi: 10.1177/0886260516682520 © The Author(s) 2016 Published by SAGEThe aim of the study was to identify the prevalence and perceived helpfulness of a variety of protective strategies that were used by female survivors of domestic abuse and to explore factors that may have influenced strategy usage. Forty participants were recruited from a voluntary sector domestic abuse service, commissioned by an outer London local authority in the UK. The measurement tools used were the Intimate Partner Violence Strategies Index and the CAADA Domestic Abuse, Stalking and ‘Honour’-Based Violence (DASH) Risk Assessment Checklist. The average age was 33 (SD=7.9, range: 20-57), half reported to be of Asian ethnicity, 37.5% White and 12.5% Black or Mixed ethnicity. The average DASH score was 9.8 (SD=13.2, range: 0-18) and an average of 18 (SD=6.7, range: 1-29) protective strategies were utilised by each participant. All of the most commonly used strategies were from the Placating category. Though Safety Planning strategies were rated as the most helpful by all participants, Placating strategies were also rated as helpful by two-thirds of participants. Stepwise multiple regression showed that Placating was the only significant predictor of DASH score (ÎČ=0.375, p<0.05) and accounted for 14% of the variance of DASH score. Findings showed that women utilized a diverse range of protective strategies with placating strategies being most intensely used and rated as helpful. However, placating strategy usage could be a risk factor as opposed to a protective factor. This study has also demonstrated that greater placating strategies were used by White than South Asian women, and women who were employed used more formal strategies. This research has extended the knowledge base of protective strategies that professionals can draw from to underpin decisions and interventions when working with domestic abuse survivors.Peer reviewedFinal Accepted Versio

    Initial-state dependence in time-dependent density functional theory

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    Time-dependent density functionals in principle depend on the initial state of the system, but this is ignored in functional approximations presently in use. For one electron it is shown there is no initial-state dependence: for any density, only one initial state produces a well-behaved potential. For two non-interacting electrons with the same spin in one-dimension, an initial potential that makes an alternative initial wavefunction evolve with the same density and current as a ground state is calculated. This potential is well-behaved and can be made arbitrarily different from the original potential
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