Analytic Scattering and Refraction Models for Exoplanet Transit Spectra

Observations of exoplanet transit spectra are essential to understanding the physics and chemistry of distant worlds. The effects of opacity sources and many physical processes combine to set the shape of a transit spectrum. Two such key processes - refraction and cloud and/or haze forward scattering - have seen substantial recent study. However, models of these processes are typically complex, which prevents their incorporation into observational analyses and standard transit spectrum tools. In this work, we develop analytic expressions that allow for the efficient parameterization of forward scattering and refraction effects in transit spectra. We derive an effective slant optical depth that includes a correction for forward scattered light, and present an analytic form of this correction. We validate our correction against a full-physics transit spectrum model that includes scattering, and we explore the extent to which the omission of forward scattering effects may bias models. Also, we verify a common analytic expression for the location of a refractive boundary, which we express in terms of the maximum pressure probed in a transit spectrum. This expression is designed to be easily incorporated into existing tools, and we discuss how the detection of a refractive boundary could help indicate the background atmospheric composition by constraining the bulk refractivity of the atmosphere. Finally, we show that opacity from Rayleigh scattering and collision induced absorption will outweigh the effects of refraction for Jupiter-like atmospheres whose equilibrium temperatures are above 400-500 K.Comment: ApJ accepted; submitted Feb. 7, 201

Electron beam-induced current imaging with two-angstrom resolution.

An electron microscope's primary beam simultaneously ejects secondary electrons (SEs) from the sample and generates electron beam-induced currents (EBICs) in the sample. Both signals can be captured and digitized to produce images. The off-sample Everhart-Thornley detectors that are common in scanning electron microscopes (SEMs) can detect SEs with low noise and high bandwidth. However, the transimpedance amplifiers appropriate for detecting EBICs do not have such good performance, which makes accessing the benefits of EBIC imaging at high-resolution relatively more challenging. Here we report lattice-resolution imaging via detection of the EBIC produced by SE emission (SEEBIC). We use an aberration-corrected scanning transmission electron microscope (STEM), and image both microfabricated devices and standard calibration grids

The Incidence of Parasitism in Iowa Cattle

The importance of cattle parasitism is gaining recognition throughout the world with more emphasis being placed on the incidence, significance and effective control of parasites. The mortality of cattle due to parasitism is relatively low but the morbidity is high due to such losses as inefficient feed utilization and retarded growth and development. Cattle parasitism has been of economic importance for some time in southern United States and in the parts of western United States were irrigation is employed. Increasing interstate movement of cattle has enlarged the area where parasitism is a problem. A fecal study of Iowa cattle was initiated in 1955 in order to determine the extent of bovine parasitism in this state

Assessing Library Services With LibQUAL+: A Case Study

There is a growing body of literature on the development of the Association of Research Libraries (ARL) assessment tool, LibQUAL+ (Cook, Heath, Thompson). Because LibQUAL+ is a fairly recent innovation, there has been little published on its use in individual libraries. The 2001 LibQUAL+ survey at Texas Tech (Kemp) and the 2002 survey at the University of Washington (Hiller) are two exceptions. Both were conducted at ARL libraries, which is appropriate as LibQUAL+ is an ARL program. ARL has announced a forthcoming title, From Data to Action: Libraries Report on Their Use of LibQUAL+™ Survey Findings, but this has yet to be published. According to the publisher’s announcement, “This special collection of articles will highlight practical examples of how libraries are using LibQUAL+ data in their local libraries as an assessment and evaluation mechanism. It will present the continued efforts in which librarians have engaged to promote service quality assessment within their respective organizations as well as externally across peer institutions.” (Askew) When reading this blurb one would expect to learn how the results of the LibQUAL+ survey were used to improve services, but nothing is promised regarding the mechanics of instituting the survey. This paper will elaborate on the survey process at a non-ARL library, from conducting the survey through the implementation of service improvements in response to the results as provided by ARL

The Interior of Jupiter

Jupiter, owing to its large mass and rapid formation, played a crucial role in shaping the solar system as we know it today. Jupiter mostly contains hydrogen and helium (more than 87% by mass), and as such bears a close resemblance to the Sun. However, the Sun has only 2% of its mass in elements other than hydrogen and helium (the heavy elements), whereas Jupiter has between 3 and 13%. The exact amount of these heavy elements in the planet and their distribution are keys to understanding how the solar system formed

Irreversibility at macromolecular scales in the flake graphite of the lithium-ion battery anode.

Charging a commercial lithium-ion battery intercalates lithium into the graphite-based anode, creating various lithium carbide structures. Despite their economic importance, these structures and the dynamics of their charging-discharging transitions are not well-understood. We have videoed single microcrystals of high-quality, natural graphite undergoing multiple lithiation-delithiation cycles. Because the equilibrium lithium-carbide compounds corresponding to full, half, and one-third charge are gold, red, and blue respectively, video observations give direct insight into both the macromolecular structures and the kinematics of charging and discharging. We find that the transport during the first lithiation is slow and orderly, and follows the core-shell or shrinking annuli model with phase boundaries moving at constant velocities (i.e. non-diffusively). Subsequent lithiations are markedly different, showing transport that is both faster and disorderly, which indicates that the initially pristine graphite is irreversibly and considerably altered during the first cycle. In all cases deintercalation is not the time-reverse of intercalation. These findings both illustrate how lithium enters nearly defect-free host material, and highlight the differences between the idealized case and an actual, cycling graphite anode

A physical activity intervention to improve the quality of life of patients with a stoma:a feasibility study protocol

Background: Physical activity (PA) is positively associated with quality of life. People with a stoma are less likely to engage in PA than those without a stoma. Methods: In this feasibility intervention study, we will perform the following: (1) Develop a PA intervention for people with a stoma. An Expert Working Group of behavioural scientists, exercise scientists, clinicians and a Patient Advisory Group of people with a bowel stoma will meet with the research team to inform the development of a PA intervention for people with a stoma. A manual of the intervention will be the main output. (2) Explore PA instructors' experiences of delivering the PA intervention. PA instructors will record on paper the number of PA consultations with each patient and a researcher will interview the PA instructors about their experiences of delivering the intervention. (3) Assess the level of patient (bowel cancer or inflammatory bowel disease (IBD) patients with a stoma between 6 weeks and 24 months postsurgery) engagement with the PA intervention and their views on intervention acceptability and usefulness. Patients will keep a PA diary to record daily pedometer recorded step count and type and duration of activities. A researcher will interview patients about their experiences of the PA intervention. (4) Assess screening, eligibility, consent, data completion, loss to follow up, and missing data rates, representativeness of participants and potential treatment effects. A researcher will record on paper all study procedure parameters. Quality of life (stoma-quality of life; Functional Assessment of Cancer Therapy, Short IBD questionnaire), fatigue (FACIT fatigue scale) and PA (accelerometer) will be measured pre- and post-intervention in patients. For IBD patients only, blood will be taken to measure systemic inflammation. Discussion: We hypothesise that a PA intervention will be an effective means of improving the quality of life of people with a stoma. Before embarking on a full randomised controlled trial to test this hypothesis, a PA intervention needs to be developed and a feasibility study of the proposed PA intervention conducted.</p

HALT (Hernia Active Living Trial):protocol for a feasibility study of a randomised controlled trial of a physical activity intervention to improve quality of life in people with bowel stoma with a bulge/parastomal hernia

Background: Parastomal hernia (PSH) can be repaired surgically, but results to date have been disappointing, with reported recurrence rates of 30 to 76%. Other types of intervention are therefore needed to improve the quality of life of people with PSH. One potential intervention is physical activity. We hypothesise that the intervention will increase core activation and control across the abdominal wall at a site of potential weakness and thus reduce the risk of PSH progression. Increases in physical activity will improve body image and quality of life (QoL). Methods: Subjects and sample There were approximately 20 adults with a bowel stoma and PSH. People with previous PSH repair will be excluded as well as people who already do core training. Study design This is a feasibility study of a randomised controlled trial with 2 months follow-up, in 2 sites using mixed methods. Stage 1 involves intervention development and in stage 2, intervention and trial parameters will be assessed. Intervention A theoretically informed physical activity intervention was done, targeting people with PSH. Main outcome of feasibility study The main outcome is the decision by an independent Study Steering Committee whether to proceed to a full randomised controlled trial of the intervention. Other outcomes We will evaluate 4 intervention parameters—fidelity, adherence, acceptability and safety and 3 trial parameters (eligible patients’ consent rate, acceptability of study design and data availability rates for following endpoints): I. Diagnosis and classification of PSHII. Muscle activation III. Body composition (BMI, waist circumference) IV. Patient reported outcomes: QoL, body image and physical functioning V. Physical activity; VI. Psychological determinants of physical activity Other data Included are other data such as interviews with all participants about the intervention and trial procedures. Data analysis and statistical power As this is a feasibility study, the quantitative data will be analysed using descriptive statistics. Audio-recorded qualitative data from interviews will be transcribed verbatim and analysed thematically. Discussion: The feasibility and acceptability of key intervention and trial parameters will be used to decide whether to proceed to a full trial of the intervention, which aims to improve body image, quality of life and PSH progression.</p