Pump linewidth requirement for optical parametric oscillators

Pumping laser bandwidth requirement for optical parametric oscillator

Recurrent PET FDG Uptake after Sequential Chemotherapy and Radiation Therapy for DLBCL of the Tibia: A Case Report and Review of the Literature

The aim of this paper is to report on the challenges associated with identifying disease recurrence following combined modality therapy (CMT) for primary lymphoma of the tibia in which an intramedullary nail has been placed. A patient with primary bone lymphoma (PBL) was treated with CMT (chemotherapy and radiation therapy). After a complete response, he has been followed for eighteen months by physical exam and radiographic imaging. Despite persistent increased tracer accumulation at the original site, he has no proven recurrence. Literature review showed a small number of retrospective, single institution reviews detailing clinical experience and expected outcome in patients treated with PBL limited to one bony site of disease. PBL presents a treatment challenge, particularly when a weight-bearing long bone is diffusely involved and followup is complicated after placement of stabilizing hardware. Close coordination of the oncology team and diagnostic radiology is required to ensure optimal outcome

Nonlinear Competition Between Small and Large Hexagonal Patterns

Recent experiments by Kudrolli, Pier and Gollub on surface waves, parametrically excited by two-frequency forcing, show a transition from a small hexagonal standing wave pattern to a triangular ``superlattice'' pattern. We show that generically the hexagons and the superlattice wave patterns bifurcate simultaneously from the flat surface state as the forcing amplitude is increased, and that the experimentally-observed transition can be described by considering a low-dimensional bifurcation problem. A number of predictions come out of this general analysis.Comment: 4 pages, RevTex, revised, to appear in Phys. Rev. Let

Pay for Performance, Satisfaction and Retention in Longitudinal Crowdsourced Research

In the social and cognitive sciences, crowdsourcing provides up to half of all research participants. Despite this popularity, researchers typically do not conceptualize participants accurately, as gig-economy worker-participants. Applying theories of employee motivation and the psychological contract between employees and employers, we hypothesized that pay and pay raises would drive worker-participant satisfaction, performance, and retention in a longitudinal study. In an experiment hiring 359 Amazon Mechanical Turk Workers, we found that initial pay, relative increase of pay over time, and overall pay did not have substantial influence on subsequent performance. However, pay significantly predicted participants\u27 perceived choice, justice perceptions, and attrition. Given this, we conclude that worker-participants are particularly vulnerable to exploitation, having relatively low power to negotiate pay. Results of this study suggest that researchers wishing to crowdsource research participants using MTurk might not face practical dangers such as decreased performance as a result of lower pay, but they must recognize an ethical obligation to treat Workers fairly

On a family of solutions of the KP equation which also satisfy the Toda lattice hierarchy

We describe the interaction pattern in the $x$-$y$ plane for a family of soliton solutions of the Kadomtsev-Petviashvili (KP) equation, $(-4u_{t}+u_{xxx}+6uu_x)_{x}+3u_{yy}=0$. Those solutions also satisfy the finite Toda lattice hierarchy. We determine completely their asymptotic patterns for $y\to \pm\infty$, and we show that all the solutions (except the one-soliton solution) are of {\it resonant} type, consisting of arbitrary numbers of line solitons in both aymptotics; that is, arbitrary $N_-$ incoming solitons for $y\to -\infty$ interact to form arbitrary $N_+$ outgoing solitons for $y\to\infty$. We also discuss the interaction process of those solitons, and show that the resonant interaction creates a {\it web-like} structure having $(N_--1)(N_+-1)$ holes.Comment: 18 pages, 16 figures, submitted to JPA; Math. Ge

A framework for power analysis using a structural equation modelling procedure

BACKGROUND: This paper demonstrates how structural equation modelling (SEM) can be used as a tool to aid in carrying out power analyses. For many complex multivariate designs that are increasingly being employed, power analyses can be difficult to carry out, because the software available lacks sufficient flexibility. Satorra and Saris developed a method for estimating the power of the likelihood ratio test for structural equation models. Whilst the Satorra and Saris approach is familiar to researchers who use the structural equation modelling approach, it is less well known amongst other researchers. The SEM approach can be equivalent to other multivariate statistical tests, and therefore the Satorra and Saris approach to power analysis can be used. METHODS: The covariance matrix, along with a vector of means, relating to the alternative hypothesis is generated. This represents the hypothesised population effects. A model (representing the null hypothesis) is then tested in a structural equation model, using the population parameters as input. An analysis based on the chi-square of this model can provide estimates of the sample size required for different levels of power to reject the null hypothesis. CONCLUSIONS: The SEM based power analysis approach may prove useful for researchers designing research in the health and medical spheres

Unveiling faculty conceptions of academic risk taking:a phenomenographic study

Among recent developments in the field of higher education is the emergence of New Public Management and of what has been labelled as ‘risk university’. The aim of this paper is to redress the lack of discussion over the role that risk taking plays in academic practice by exploring what faculty understand academic risk taking to be and how they enact this understanding in their tasks. Drawing on a phenomenographic perspective and semi-structured interviews with 20 faculty members from a high-profile UK university, we find that academic risk taking is experienced in four qualitatively different ways. Our results suggest that although academics engage in relatively similar endeavours, they exhibit various approaches to these endeavours due to their different conceptions of what constitutes academic risk taking. These findings have implications for the literature on identity construction and the debate over how the greater accountability of academic activity is affectively experienced

On the equivalence of different approaches for generating multisoliton solutions of the KPII equation

The unexpectedly rich structure of the multisoliton solutions of the KPII equation has been explored by using different approaches, running from dressing method to twisting transformations and to the tau-function formulation. All these approaches proved to be useful in order to display different properties of these solutions and their related Jost solutions. The aim of this paper is to establish the explicit formulae relating all these approaches. In addition some hidden invariance properties of these multisoliton solutions are discussed