Matching small β\beta functions using centroid jitter and two beam position monitors

Matching to small beta functions is required to preserve emittance in plasma accelerators. The plasma wake provides strong focusing fields, which typically require beta functions on the mm-scale, comparable to those found in the final focusing of a linear collider. Such beams can be time consuming to experimentally produce and diagnose. We present a simple, fast, and noninvasive method to measure Twiss parameters in a linac using two beam position monitors only, relying on the similarity of the beam phase space and the jitter phase space. By benchmarking against conventional quadrupole scans, the viability of this technique was experimentally demonstrated at the FLASHForward plasma-accelerator facility.Comment: 8 pages, 7 figure

Can quantum fractal fluctuations be observed in an atom-optics kicked rotor experiment?

We investigate the parametric fluctuations in the quantum survival probability of an open version of the delta-kicked rotor model in the deep quantum regime. Spectral arguments [Guarneri I and Terraneo M 2001 Phys. Rev. E vol. 65 015203(R)] predict the existence of parametric fractal fluctuations owing to the strong dynamical localisation of the eigenstates of the kicked rotor. We discuss the possibility of observing such dynamically-induced fractality in the quantum survival probability as a function of the kicking period for the atom-optics realisation of the kicked rotor. The influence of the atoms' initial momentum distribution is studied as well as the dependence of the expected fractal dimension on finite-size effects of the experiment, such as finite detection windows and short measurement times. Our results show that clear signatures of fractality could be observed in experiments with cold atoms subjected to periodically flashed optical lattices, which offer an excellent control on interaction times and the initial atomic ensemble.Comment: 18 pp, 7 figs., 1 tabl

Book Reviews

Book Reviews: Overthrow: America's Century of Regime Change From Hawaii to Iraq by Stephen Kinzer ; Longitude and Empire: How Captain Cook's Voyages Changed the World by Brian W. Richardson ; Pacific Encounters: Art & Diversity in Polynesia 1760-1860 by Steven Hooper ; All Men Are Brothers: The Life & Times of Francis Williams Damon by Paul Berry ; Broken Trust: Greed, Mismanagement, & Political Manipulation at America's Largest Charitable Trust by Samuel P. King and Randall W. Roth ; Crowning the Nice Girl: Gender, Ethnicity, and Culture in Hawai'i's Cherry Blossom Festival by Christine R. Yano ; Combat Chaplain: The Personal Story of the World War II Chaplain of the Japanese American 100th Battalion by Israel A. S. Yost ; Hawaiian Volcanoes by Clarence Edward Dutton ; Reworking Race: The Making of Hawaii's Interracial Labor Movement by Moon-Kie Jung ; Islands in a Far Sea: The Fate of Nature in Hawai'i by John L. Culliney

Exploring women's sensory experiences of undergoing colposcopy and related procedures: implications for preparatory sensory information provision

INTRODUCTION: Some women experience distress during colposcopy examinations which is partly related to women's fear, or experience, of pain during the procedure. However, little is known about women's sensory experiences of colposcopy (other than pain) or what might impact on these experiences. The aim of this study was to explore women's sensory experiences of colposcopy and related procedures and identify factors which influenced negative sensory experiences. METHODS: In-depth interviews were conducted with 23 women who had undergone, for the first time, a colposcopy (some with related procedures, including punch biopsies and loop excision) as part of follow-up for abnormal cervical cytology. Interviews were analysed thematically using the Framework Approach to organise the data and identify emerging higher-order themes. RESULTS: Women described a range of sensory experiences including pain or discomfort, cramping, stinging and cold sensations (due to the application of acetic acid to the cervix). Four key themes emerged as important aspects of the overall sensory experience: levels of pain, treatment-specific sensations, anaesthetic-specific sensations and solution-specific sensations. Factors that may influence women having a negative sensory experience were sensory expectations of the procedure(s) and lack of preparatory sensory information. DISCUSSION: Our study provides unique in-depth insight into women's sensory experiences of colposcopy and related procedures and suggests women require more preparatory sensory information. The issues identified as contributing to women having a negative sensory experience may help inform the development of pre-colposcopy information which may better prepare women with abnormal cervical cytology for follow-up examinations

Arnol'd Tongues and Quantum Accelerator Modes

The stable periodic orbits of an area-preserving map on the 2-torus, which is formally a variant of the Standard Map, have been shown to explain the quantum accelerator modes that were discovered in experiments with laser-cooled atoms. We show that their parametric dependence exhibits Arnol'd-like tongues and perform a perturbative analysis of such structures. We thus explain the arithmetical organisation of the accelerator modes and discuss experimental implications thereof.Comment: 20 pages, 6 encapsulated postscript figure

Morphological Instabilities in a growing Yeast Colony: Experiment and Theory

We study the growth of colonies of the yeast Pichia membranaefaciens on agarose film. The growth conditions are controlled in a setup where nutrients are supplied through an agarose film suspended over a solution of nutrients. As the thickness of the agarose film is varied, the morphology of the front of the colony changes. The growth of the front is modeled by coupling it to a diffusive field of inhibitory metabolites. Qualitative agreement with experiments suggests that such a coupling is responsible for the observed instability of the front.Comment: RevTex, 4 pages and 3 figure

Effect of Biodiversity Changes in Disease Risk: Exploring Disease Emergence in a Plant-Virus System

The effect of biodiversity on the ability of parasites to infect their host and cause disease (i.e. disease risk) is a major question in pathology, which is central to understand the emergence of infectious diseases, and to develop strategies for their management. Two hypotheses, which can be considered as extremes of a continuum, relate biodiversity to disease risk: One states that biodiversity is positively correlated with disease risk (Amplification Effect), and the second predicts a negative correlation between biodiversity and disease risk (Dilution Effect). Which of them applies better to different host-parasite systems is still a source of debate, due to limited experimental or empirical data. This is especially the case for viral diseases of plants. To address this subject, we have monitored for three years the prevalence of several viruses, and virus-associated symptoms, in populations of wild pepper (chiltepin) under different levels of human management. For each population, we also measured the habitat species diversity, host plant genetic diversity and host plant density. Results indicate that disease and infection risk increased with the level of human management, which was associated with decreased species diversity and host genetic diversity, and with increased host plant density. Importantly, species diversity of the habitat was the primary predictor of disease risk for wild chiltepin populations. This changed in managed populations where host genetic diversity was the primary predictor. Host density was generally a poorer predictor of disease and infection risk. These results support the dilution effect hypothesis, and underline the relevance of different ecological factors in determining disease/infection risk in host plant populations under different levels of anthropic influence. These results are relevant for managing plant diseases and for establishing conservation policies for endangered plant species

Spiral cracks in drying precipitates

We investigate the formation of spiral crack patterns during the desiccation of thin layers of precipitates in contact with a substrate. This symmetry-breaking fracturing mode is found to arise naturally not from torsion forces, but from a propagating stress front induced by the fold-up of the fragments. We model their formation mechanism using a coarse-grain model for fragmentation and successfully reproduce the spiral cracks. Fittings of experimental and simulation data show that the spirals are logarithmic, corresponding to constant deviation from a circular crack path. Theoretical aspects of the logarithmic spirals are discussed. In particular we show that this occurs generally when the crack speed is proportional to the propagating speed of stress front.Comment: 4 pages, 5 figures, RevTe

The effect of geriatric care on health care use

Health care for older adults with chronic conditions is costly and often of suboptimal quality. The quality of health care for geriatric conditions such as dementia and incontinence may be considerably poorer than for chronic disease such as diabetes and hypertension. Geriatricians have extensive training in and experience with physical, mental, cognitive, and social issues related to aging. Many elders might benefit from geriatric care; however, the current and projected future supply of geriatricians is limited. An understanding of the use and effects of geriatric care will help to ensure that the existing supply of geriatricians is used efficiently and provide information about possible benefits of expending supply. The purpose of this dissertation is to describe the use of geriatric care, to evaluate whether geriatric care reduces emergency department use, and to determine whether geriatric care is typically used in lieu of or in combination with care from other types of physicians. Using Medicare claims data for a national sample of elders who had a recent hospitalization for acute coronary syndromes and subsequent diagnosis of a geriatric condition, we found that very few patients received geriatric care. Use of geriatric care was closely tied to metropolitan status and nursing home residency. Geriatric care was associated with reduced emergency department use for both community and nursing home residents. Geriatric consultative care was associated with a reduction in emergency department use that was not statistically different from the reduction associated with geriatric primary care. Geriatric care was associated with fewer visits to family and internal medicine physicians and in some cases with fewer visits to specialists. Although our results suggest that geriatric care reduces emergency department use, the total clinical impact of geriatric care is likely to be very small because of the low supply of geriatricians. Because of the lack of existing literature on the topic, additional studies are needed to elucidate the use and effects of geriatric care in real-world clinical settings. However, for geriatric medicine to have a population-level impact on the health and health care of older adults, its focus may need to be on teaching, research, and advocacy/policymaking