High-order harmonic generation from Rydberg states at fixed Keldysh parameter

Because the commonly adopted viewpoint that the Keldysh parameter $\gamma$ determines the dynamical regime in strong field physics has long been demonstrated to be misleading, one can ask what happens as relevant physical parameters, such as laser intensity and frequency, are varied while $\gamma$ is kept fixed. We present results from our one- and fully three-dimensional quantum simulations of high-order harmonic generation (HHG) from various bound states of hydrogen with $n$ up to 40, where the laser intensities and the frequencies are scaled from those for $n=1$ in order to maintain a fixed Keldysh parameter $\gamma$$< 1$ for all $n$. We find that as we increase $n$ while keeping $\gamma$ fixed, the position of the cut-off scales in well defined manner. Moreover, a secondary plateau forms with a new cut-off, splitting the HHG plateau into two regions. First of these sub-plateaus is composed of lower harmonics, and has a higher yield than the second one. The latter extends up to the semiclassical $I_p+3.17U_p$ cut-off. We find that this structure is universal, and the HHG spectra look the same for all $n\gtrsim 10$ when plotted as a function of the scaled harmonic order. We investigate the $n$-, $l$- and momentum distributions to elucidate the physical mechanism leading to this universal structure

Phase-dependent interference fringes in the wavelength scaling of harmonic efficiency

We describe phase-dependent wavelength scaling of high-order harmonic generation efficiency driven by ultra-short laser fields in the mid-infrared. We employ both numerical solution of the time-dependent Schr\"{o}dinger equation and the Strong Field Approximation to analyze the fine-scale oscillations in the harmonic yield in the context of channel-closing effects. We show, by varying the carrier-envelope phase, that the amplitude of these oscillations depend strongly on the number of returning electron trajectories. Furthermore, the peak positions of the oscillations vary significantly as a function of the carrier-envelope phase. Owing to its practical applications, we also study the wavelength dependence of harmonic yield in the "single-cycle" limit, and observe a smooth variation in the wavelength scaling originating from the vanishing fine-scale oscillations.Comment: 5 pages, 4 figure

The Role of Shared Book Reading on Early Literacy: The Effects in terms of Home and School Environment

Shared book reading is a social activity in which an adult reads a book to a child or a group of children by expecting a different rate of participation from the child according to the type of reading. The literature supports that, during shared book reading process, children improve the abilities of receptive and expressive language; and depending on the technique of reading they improve the abilities of phonological awareness and print awareness. Important body of research shows that different practices of reading ((a) dialogic reading, (b) shared book reading, (c) interactive shared book reading, (d) print referencing) are used for the field of early intervention. As the most useful techniques among the early intervention techniques in which book-sharing was used, are interactive shared book reading and dialogic reading, which gave the child the most active role. There are some variables that affect the output during shared book reading. Depending on that fact, the attitudes and behaviours of the adults; the number of the children in the interaction; home and school context; following the interest of the children and expanding their answers; asking open-ended questions and children’s active participation to the reading process are the factors that affect the shared book reading interaction. Some researchers claim that gender of the parent is another variable in this interaction. This research examines the different practices of shared book reading, the benefits of these specific practices and the variables which are considered as effective in shared book reading interaction

Mycobacterial infection of intraparenchymal bronchogenic cysts

Bronchogenic cysts (BCs) may rarely cause some interesting and unusual complications. Although infection is a common complication of BCs, there are only two patients with BC infected with mycobacterium in English literature. Two intraparencymal BCs infected with mycobacterium are presented here as unusual complications. Cystectomy was performed for the cysts. They were given antituberculosis treatment. No complication or recurrences were detected in follow up period. © 2006 Elsevier Ltd. All rights reserved

Learning Interpretable Temporal Properties from Positive Examples Only

We consider the problem of explaining the temporal behavior of black-boxsystems using human-interpretable models. To this end, based on recent researchtrends, we rely on the fundamental yet interpretable models of deterministicfinite automata (DFAs) and linear temporal logic (LTL) formulas. In contrast tomost existing works for learning DFAs and LTL formulas, we rely on onlypositive examples. Our motivation is that negative examples are generallydifficult to observe, in particular, from black-box systems. To learnmeaningful models from positive examples only, we design algorithms that relyon conciseness and language minimality of models as regularizers. To this end,our algorithms adopt two approaches: a symbolic and a counterexample-guidedone. While the symbolic approach exploits an efficient encoding of languageminimality as a constraint satisfaction problem, the counterexample-guided onerelies on generating suitable negative examples to prune the search. Both theapproaches provide us with effective algorithms with theoretical guarantees onthe learned models. To assess the effectiveness of our algorithms, we evaluateall of them on synthetic data.<br

Gossypol Interferes with Both Type I and Type II Topoisomerase Activities Without Generating Strand Breaks

A considerable number of agents with chemotherapeutic potentials reported over the past years were shown to interfere with the reactions of DNA topoisomerases, the essential enzymes that regulate conformational changes in DNA topology. Gossypol, a naturally occurring bioactive phytochemical is a chemopreventive agent against various types of cancer cell growth with a reported activity on mammalian topoisomerase II. The compounds targeting topoisomerases vary in their mode of action; class I compounds act by stabilizing covalent topoisomerase-DNA complexes resulting in DNA strand breaks while class II compounds interfere with the catalytic function of topoisomerases without generating strand breaks. In this study, we report Gossypol as the interfering agent with type I topoisomerases as well. We also carried out an extensive set of assays to analyze the type of interference manifested by Gossypol on DNA topoisomerases. Our results strongly suggest that Gossypol is a potential class II inhibitor as it blocked DNA topoisomerase reactions with no consequently formed strand breaks. © 2012 Springer Science+Business Media New York

Investigation of efficacy of mitomycin-C, Sodium hyaluronate and human amniotic fluid in preventing epidural fibrosis and adhesion using a rat laminectomy model

Study Design: A retrospective study. Purpose: The aim of this study was to evalute the effects of mitomycin-C, sodium hyaluronate and human amniotic fluid on preventing spinal epidural fibrosis. Overview of Literature: The role of scar tissue in pain formation is not exactly known, but it is reported that scar tissue causes adhesions between anatomic structures. Intensive fibrotic tissue compresses on anatomic structures and increases the sensitivity of the nerve root for recurrent herniation and lateral spinal stenosis via limiting movements of the root. Also, neuronal atrophy and axonal degeneration occur under scar tissue. Methods: The study design included 4 groups of rats: group 1 was the control group, groups 2, 3, and 4 receieved antifibrotic agents, mitomycin-C (group 2), sodium hyaluronate (group 3), and human amniotic fluid (group 4). Midline incision for all animals were done on L5 for total laminectomy. Four weeks after the surgery, the rats were sacrificed and specimens were stained with hematoxylineosin and photos of the slides were taken for quantitive assesment of the scar tissue. Results: There was no significant scar tissue in the experimental animals of groups 2, 3, and 4. It was found that there was no significant difference between drug groups, but there was a statistically significant difference between the drug groups and the control group. Conclusions: This experimental study shows that implantation of mitomycin-C, sodium hyaluronate and human amniotic fluid reduces epidural fibrosis and adhesions after spinal laminectomy in rat models. Further studies in humans are needed to determine the complications of the agents researched. © 2013 by Korean Society of Spine Surgery

The Role of MeCP2 in Brain Development and Neurodevelopmental Disorders

Methyl CpG binding protein-2 (MeCP2) is an essential epigenetic regulator in human brain development. Rett syndrome, the primary disorder caused by mutations in the X-linked MECP2 gene, is characterized by a period of cognitive decline and development of hand stereotypies and seizures following an apparently normal early infancy. In addition, MECP2 mutations and duplications are observed in a spectrum of neurodevelopmental disorders, including severe neonatal encephalopathy, X-linked mental retardation, and autism, implicating MeCP2 as an essential regulator of postnatal brain development. In this review, we compare the mutation types and inheritance patterns of the human disorders associated with MECP2. In addition, we summarize the current understanding of MeCP2 as a central epigenetic regulator of activity-dependent synaptic maturation. As MeCP2 occupies a central role in the pathogenesis of multiple neurodevelopmental disorders, continued investigation into MeCP2 function and regulatory pathways may show promise for developing broad-spectrum therapies