Controlling nonlinear optics with dispersion in photonic crystal fibres

Nonlinear optics enables the manipulation of the spectral and temporal features of light. We used the tailorable guidance properties of photonic crystal fibres to control and enhance nonlinear processeswith the aim of improving nonlinearity based optical sources. We utilised modern, high power, Ytterbium fibre lasers to pump either single photonic crystal fibres or a cascade of fibres with differing properties. Further extension of our control was realised with specifically tapered photonic crystal fibres which allowed for a continuous change in the fibre characteristics along their length. The majority of our work was concerned with supercontinuum generation. For continuous wave pumping we developed a statistical model of the distribution of soliton energies arising from modulational instability and used it to understand the optimum dispersion for efficient continuum expansion. A two-fold increase in spectral width was demonstrated, along with studies of the noise properties and pump bandwidth dependence of the continuum. For picosecond pumping we found that the supercontinuum bandwidth was limited by the four wave mixing phase-matching available in a single fibre. A technique to overcome this by using a cascade of fibres with different dispersion profiles was developed. Further improvement was achieved by using novel tapered PCFs to continuously extend the phase-matching. Analysis of this case showed that a key role was played by soliton trapping of dispersive waves and that our tapers strongly enhanced this effect. We demonstrated supercontinua spanning 0.34-2.4 ¹mwith an unprecedented spectral power; up to 5 mW/nm. The use of long, dispersion decreasing photonic crystal fibres enabled us to demonstrate adiabatic soliton compression at 1.06 ¹m. From a survey of fibre structures we found that working around the second zero dispersion wavelength was optimal as this allows for decreasing dispersion without decreasing the nonlinearity. We achieved compression ratios of over 15

Alien Registration- Colins, Tony (Rockland, Knox County)

https://digitalmaine.com/alien_docs/14797/thumbnail.jp

The role of endogenous Bcl-xL in regulation of apoptotic signaling pathways.

Bcl-2 proteins are major regulators of cellular responses to various apoptotic stimuli. Among them, overexpression of the anti-apoptotic BcI-2 protein BcI-xL modulates organelle-specific apoptotic pathways. To understand the mechanisms by which endogenous BcI-xL regulates apoptosis, mouse embryonic fibroblasts (MEFs) deficient in BcI-xL expression (Bcl-x-KO) was generated. Studies of BcI-xL exclusively targeted to an organelle in Bcl-x-KO MEFs indicate that the mitochondria- and ER-Iocalized BcI-xL play distinct roles in apoptosis resistance and Ca2+ homeostasis. Specifically, mitochondrial BcI-xL can regulate apoptosis independently of ER BcI-xL, and when localized exclusively at the ER, BcI-xL impinges on Ca2+ homeostasis but does not affect apoptosis unless BcI-xL is present in additional cellular compartments. Furthermore, I investigated how Bcl-2 proteins, especially Bcl-xL, might regulate oxidative stress-induced apoptosis. My studies reveal a signaling pathway, in which the oxidative stress inducer hydrogen peroxide (H202) activates Noxa, leading to a decrease in Mcl-1 expression levels and subsequent increase in apoptosis in the absence of BcI-xL expression. Finally, I studied the exact roles of lysosomal membrane permeabilization in apoptosis cascade triggered by oxidative stress and how LMP is regulated by the complex Bcl-2 protein network. My studies elucidate a novel molecular mechanism that couples lysosomal membrane permeabilization with mitochondrial membrane permeabilization and ultimate cell death during oxidative stress-induced apoptosis

Quality of life and better than Well: a mixed method study of long term (post 5 years) recovery and recovery capital

Purpose: To compare quality of life scores in a long term recovery population group (post 5 years) with a general population group and to explore how any differences might be explained by recovering individuals themselves in a small number of follow up qualitative interviews. Design: A sequential explanatory mixed method design combining quantitative Quality of Life measure (WHOQOL-Bref,WHO 1996) and six subsequent semistructured individual interviews. The Quality of Life measure compared long term recovery scores (post 5 years) with the general population group. The subsequent qualitative semi-structured interviews explored what the participants themselves said about their recovery. Findings: The quantitative data provides evidence of a significant difference in Quality of Life (WHOQoL-BREF) in two domains. The long term recovery group (5 or more years into recovery) scored higher in both the environment and psychological domains than the general population group. Of the long term recovery group 17 people who still accessed mutual aid scored higher in all four domains than those 23 people who did not. The interviews provide evidence of the this difference as result of growth in psychological elements of recovery such as developing perspective, improvement in self-esteem, spirituality, as well as contributing as part of wider social involvement. Research implications: This study provides support for the Quality of Life measure as useful in recovery research. The empirical data supports the concept of recovery involving improvements in many areas of life and potentially beyond the norm, termed 'better than well' (Best & Lublam 2012, Valentine, 2011). (Hibbert & Best, 2011). Originality/value: One of small number of studies using with participants who have experienced long term (post five years) recovery, also using Quality of Life measure (WHOQOL-Bref, WHO 1996) with this population. keywords: Recovery capital, Quality of Life, Public Health, Better than Wel

Psychiatric disorders and future violent arrests : a prospective study among detained girls

This study scrutinizes if detained girls with psychiatric disorders were at risk for future violent arrests during adolescence. A structured diagnostic interview was performed to determine the presence of various psychiatric disorders in 313 detained girls. Official juvenile arrest records were collected. With three exceptions that are in need of replication, psychiatric disorders (e.g., post-traumatic stress disorder, subtypes of conduct disorder), psychiatric disorder categories (e.g., anxiety disorders), and psychiatric comorbidity patterns were not prospectively related to future violent arrests. Our findings suggest that detained girls with psychiatric disorders should not be considered more dangerous than their counterparts without disorders, at least not during adolescence

Actividades matemáticas que incitan a la modelización

[EN] This proposal uses advanced mathematical concepts adapted to high school education, using intuitive and inspiring activities. Mathematics is presented as a consequence of logical reasoning, promoting learning through experimentation and focusing on modelling through physical experience and manipulation of objects. During the development work three mathematical workshops are proposed (Annexes I, II and III) who try to change the preconception that the students have about mathematics as difficult and inaccessible. For the workshops will be used top-level mathematical concepts such as: graph theory, game theory, knot theory, the proof by induction, the reduction to absurdity...[ES] En esta propuesta se emplean conceptos de matemática avanzada adaptados a la enseñanza preuniversitaria, utilizando actividades intuitivas e inspiradoras. Se presenta la matemática como fruto del razonamiento lógico, fomentando el aprendizaje basado en la experimentación y focalizando la modelización a través de la experiencia física y la manipulación de objetos. Durante el desarrollo del trabajo se proponen tres talleres matemáticos (Anexos I, II y III) que pretenden cambiar la preconcepción que tienen los alumnos sobre la matemática como difícil e inaccesible. Para la realización de los talleres se usarán conceptos matemáticos de nivel superior como son: la teoría de grafos, la teoría de juego, la teoría de nudos, las demostración por inducción, la reducción al absurdo...Falcó, J. (2012). Actividades matemáticas que incitan a la modelización. Modelling in Science Education and Learning. 5:77-91. doi:10.4995/msel.2012.2135SWORD77915Colins, Adams. (2004) Why knot?: an introduction to the mathematical theory of knots, Key College.Garner, Martin (1995). Circo matemático. Alianza Editorial