Applications of the Fractional-Random-Weight Bootstrap

The bootstrap, based on resampling, has, for several decades, been a widely used method for computing confidence intervals for applications where no exact method is available and when sample sizes are not large enough to be able to rely on easy-to-compute large-sample approximate methods, such a Wald (normal-approximation) confidence intervals. Simulation based bootstrap intervals have been proven useful in that their actual coverage probabilities are close to the nominal confidence level in small samples. Small samples analytical approximations such as the Wald method, however, tend to have coverage probabilities that greatly exceed the nominal confidence level. There are, however, many applications where the resampling bootstrap method cannot be used. These include situations where the data are heavily censored, logistic regression when the success response is a rare event or where there is insufficient mixing of successes and failures across the explanatory variable(s), and designed experiments where the number of parameters is close to the number of observations. The thing that these three situations have in common is that there may be a substantial proportion of the resamples where is not possible to estimate all of the parameters in the model. This paper reviews the fractional-random-weight bootstrap method and demonstrates how it can be used to avoid these problems and construct confidence intervals. For the examples, it is seen that the fractional-random-weight bootstrap method is easy to use and has advantages over the resampling method in many challenging applications

Reproductive toxicity of the water accommodated fraction (WAF) of crude oil in the polychaetes Arenicola marina (L.) and Nereis virens (Sars).

addresses: School of Biosciences, Hatherley Laboratories, University of Exeter, Prince of Wales Road, Exeter EX4 4PS, UK. [email protected]: Journal Article; Research Support, Non-U.S. Gov'tCopyright © 2008 Elsevier. NOTICE: This is the author’s version of a work accepted for publication by Elsevier. Changes resulting from the publishing process, including peer review, editing, corrections, structural formatting and other quality control mechanisms, may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Aquatic Toxicology, 2008, Vol. 90, Issue 1, pp. 73 – 81 DOI: http://dx.doi.org/10.1016/j.aquatox.2008.08.001Accidental pollution incidents are common in the marine environment and are often caused by oil-related activities. Here the potential of such an incident to disrupt reproduction in two polychaete species is investigated, using an environmentally relevant preparation of weathered Forties crude oil, i.e. the water accommodated fraction (WAF). Oocytes were collected and exposed to three concentrations of WAF for 1h prior to the addition of sperm, so that fertilization took place under exposure conditions. Fertilization success was significantly reduced in both species by an exposure to WAF concentrations equivalent to 0.38 mgL(-1) PAHs, to just 26.8% in Arenicola marina compared to 76% in Nereis virens. The effects of WAF exposure on fertilization were greatly enhanced at lower sperm concentrations in N. virens, with a complete lack of fertilization reactions observed at sperm concentrations of 10(3)sperm per mL. We therefore suggest a mechanism of toxicity related to sperm swimming behaviour, resulting in reduced sperm:egg collision rates. WAF was found to reduce post-fertilization development rates and have teratogenic effects on early embryonic stages in both species, which exhibited abnormal cleavage patterns and high levels of fluctuating asymmetry. These results illustrate how the presence of crude oil in its soluble form in seawater at the time of a spawning event for either A. marina or N. virens could impact on fertilization success with implications for the fertilization ecology of these free spawning marine invertebrates

Assessment and risk reduction of infectious pathogens on chiropractic treatment tables

<p>Abstract</p> <p>Background</p> <p>To investigate the presence of pathogenic microbes on chiropractic treatment tables in one outpatient teaching clinic. Additional aims were to test inexpensive disinfectants on tables that may kill microbes and suggest infection control measures for chiropractic offices, clinics and classrooms. The aim of the study was to assess the presence of pathogenic microbes on treatment tables in one outpatient teaching clinic and determine a simple behavioral model for infection control including table disinfection and accepted hand washing and sanitizing protocols.</p> <p>Methods</p> <p>10 treatment tables were selected and sampled for possible microbial flora on face and hand pieces. Samples were cultured on MacConky's agar and mannitol salt agar, labeled and incubated for up to 48 hours. Confirmatory testing of microbes to determine if drug resistant flora were present was performed. Among tables tested, 5 were selected to test disinfectants. One-half of the face piece and 1 hand piece were treated with two different wipes and then post-tested for microbes.</p> <p>Results</p> <p>Pathogenic microbes were present on chiropractic treatment tables including methicillin-resistant <it>Staph aureus</it>. Simple disinfectants neutralized the pathogens. A rudimentary disinfection procedure and infection control measures are suggested based on the findings.</p> <p>Conclusion</p> <p>Pathogenic microbes may be present on chiropractic treatment tables and can be effectively killed with proper disinfecting. Hand washing/sanitizing is an important measure in infection control as is table disinfecting. Rudimentary behavioral changes to improve chiropractic clinic infection control are needed. More comprehensive behavioral models are needed. All teaching clinics and private chiropractic offices should adopt infection control practices including routine table disinfecting and hand sanitizing. Effective measures can be put in place at minimal costs. Accrediting bodies of chiropractic institutions should mandate an infection control plan for member institutions immediately.</p

Design and performance of the PALM-3000 3.5 kHz upgrade

PALM-3000 (P3K), the second-generation adaptive optics (AO) instrument for the 5.1 meter Hale telescope at Palomar Observatory, underwent a significant upgrade to its wavefront sensor (WFS) arm and real-time control (RTC) system in late 2019. Main features of this upgrade include an EMCCD WFS camera capable of 3.5 kHz framerates and advanced Digital Signal Processor (DSP) boards to replace the aging GPU based real-time control system. With this upgrade P3K is able to maintain a lock on natural guide stars fainter than mV=16. Here we present the design and on-sky re-commissioning results of the upgraded system

DARKNESS: A Microwave Kinetic Inductance Detector Integral Field Spectrograph for High-Contrast Astronomy

We present DARKNESS (the DARK-speckle Near-infrared Energy-resolving Superconducting Spectrophotometer), the first of several planned integral field spectrographs to use optical/near-infrared Microwave Kinetic Inductance Detectors (MKIDs) for high-contrast imaging. The photon counting and simultaneous low-resolution spectroscopy provided by MKIDs will enable real-time speckle control techniques and post-processing speckle suppression at framerates capable of resolving the atmospheric speckles that currently limit high-contrast imaging from the ground. DARKNESS is now operational behind the PALM-3000 extreme adaptive optics system and the Stellar Double Coronagraph at Palomar Observatory. Here we describe the motivation, design, and characterization of the instrument, early on-sky results, and future prospects.Comment: 17 pages, 17 figures. PASP Publishe

DARKNESS: A Microwave Kinetic Inductance Detector Integral Field Spectrograph for High-contrast Astronomy

We present DARKNESS (the DARK-speckle Near-infrared Energy-resolving Superconducting Spectrophotometer), the first of several planned integral field spectrographs to use optical/near-infrared Microwave Kinetic Inductance Detectors (MKIDs) for high-contrast imaging. The photon counting and simultaneous low-resolution spectroscopy provided by MKIDs will enable real-time speckle control techniques and post-processing speckle suppression at frame rates capable of resolving the atmospheric speckles that currently limit high-contrast imaging from the ground. DARKNESS is now operational behind the PALM-3000 extreme adaptive optics system and the Stellar Double Coronagraph at Palomar Observatory. Here, we describe the motivation, design, and characterization of the instrument, early on-sky results, and future prospects

A checklist for assessing the methodological quality of concurrent tES-fMRI studies (ContES checklist): a consensus study and statement

Background: Low intensity transcranial electrical stimulation (tES), including alternating or direct current stimulation (tACS or tDCS), applies weak electrical stimulation to modulate the activity of brain circuits. Integration of tES with concurrent functional magnetic resonance imaging (fMRI) allows for the mapping of neural activity during neuromodulation, supporting causal studies of both brain function and tES effects. Methodological aspects of tES-fMRI studies underpin the results, and reporting them in appropriate detail is required for reproducibility and interpretability. Despite the growing number of published reports, there are no consensus-based checklists for disclosing methodological details of concurrent tES-fMRI studies. Objective: To develop a consensus-based checklist of reporting standards for concurrent tES-fMRI studies to support methodological rigor, transparency, and reproducibility (ContES Checklist). Methods: A two-phase Delphi consensus process was conducted by a steering committee (SC) of 13 members and 49 expert panelists (EP) through the International Network of the tES-fMRI (INTF) Consortium. The process began with a circulation of a preliminary checklist of essential items and additional recommendations, developed by the SC based on a systematic review of 57 concurrent tES-fMRI studies. Contributors were then invited to suggest revisions or additions to the initial checklist. After the revision phase, contributors rated the importance of the 17 essential items and 42 additional recommendations in the final checklist. The state of methodological transparency within the 57 reviewed concurrent tES-fMRI studies was then assessed using the checklist. Results: Experts refined the checklist through the revision and rating phases, leading to a checklist with three categories of essential items and additional recommendations: (1) technological factors, (2) safety and noise tests, and (3) methodological factors. The level of reporting of checklist items varied among the 57 concurrent tES-fMRI papers, ranging from 24% to 76%. On average, 53% of checklist items were reported in a given article. Conclusions: Use of the ContES checklist is expected to enhance the methodological reporting quality of future concurrent tES-fMRI studies, and increase methodological transparency and reproducibility

Knowledge of Names for in- and Outgroup Members of Different Sex and Ethnic Groups

Two studies were conducted to test the notion that members of outgroups would report more names for outgroups and for ingroups than members of ingroups. In the first study Black and Chicano students listed more names for themselves and for whites than did white students. In the second study female students listed more names for themselves and for males than did male students. Analysis of the most common names listed showed that in- and outgroups share use of many names but also have some names which are exclusive to their own group. It was suggested that the number of names listed by persons might be affected by intelligence or other personality variables. Further ideas for using the name listing method were proposed. </jats:p