The Calibration of the HST Kuiper Belt Object Search: Setting the Record Straight

The limiting magnitude of the HST data set used by Cochran et al. (1995) to detect small objects in the Kuiper belt is reevaluated, and the methods used are described in detail. It is shown, by implanting artificial objects in the original HST images, and re-reducing the images using our original algorithm, that the limiting magnitude of our images (as defined by the 50% detectability limit) is $V=28.4$. This value is statistically the same as the value found in the original analysis. We find that $\sim50$ of the moving Kuiper belt objects with $V=27.9$ are detected when trailing losses are included. In the same data in which these faint objects are detected, we find that the number of false detections brighter than $V=28.8$ is less than one per WFPC2 image. We show that, primarily due to a zero-point calibration error, but partly due to inadequacies in modeling the HST'S data noise characteristics and Cochran et al.'s reduction techniques, Brown et al. 1997 underestimate the SNR of objects in the HST dataset by over a factor of 2, and their conclusions are therefore invalid.Comment: Accepted to ApJ Letters; 10 pages plus 3 figures, LaTe

Late noninvasive evaluation of cardiac performance in mildly symptomatic older patients with Ebstein's anomaly of tricuspid valve: Role of radionuclide imaging

AbstractTen patients 8 to 54 years of age with isolated Ebstein's anomaly of the tricuspid valve were evaluated by electrocardiography, maximal exercise treadmill testing, 24 h electrocardiographs (ECG) monitoring, echocardiography and rest radionuclide imaging of the left ventricle. The patients presented after the 1st year of life and had not undergone surgical intervention. All except one were in functional class II. No patient had preexcitation on the surface ECG, but abnormal tachyarrhythmias or bradyarrhythmias were seen in five patients on 24 h ECG monitoring. Subnormal exercise performance was observed in five patients.Echocardiography demonstrated typical variable tricuspid valve displacement and paradoxic interventricular septal motion. Left ventricular end-diastolic dimensions were normal in all patients, but posterior wall motion was reduced in two. Moderate to severe tricuspid regurgitation with a Doppler jet velocity <2.5 m/s was demonstrated in eight patients. Left ventricular radionuclide scintigraphy revealed a subnormal ejection fraction (<50%) in 5 of 10 patients; these 5 had previously shown suboptimal exercise performance.The two youngest patients (<15 years) had no arrhythmia, normal exercise performance and normal left ventricular ejection fraction. There was no correlation between the degree of tricuspid valve displacement or régurgitation and the presence of rhythm disturbance, exercise performance or radionuclide left ventricular function.Late evaluation of patients with Ebstein's anomaly may demonstrate significant unsuspected abnormalities in cardiac rhythm, exercise performance and left ventricular function. Radionuclide scintigraphy is a useful noninvasive technique for assessing left ventricular dysfunction in these patients

Improving Newborn Hearing Screening Through Collaboration and Communication

Purpose: Hearing loss is the number one birth defect among children. There are significant consequences of delayed diagnosis and failure to obtain timely intervention, particularly for a child’s speech and language development. Design and implementation of successful newborn hearing screening (NHS) programs can be challenging. The purpose of this paper is to demonstrate improved efficiency and effectiveness of a large NHS program through the implementation of a team approach engaging both ambulatory and hospital services. Methodology: A Strengths, Weaknesses, Opportunities, and Threats (SWOT) analysis was used to develop an improved NHS program focused on improving patient care. The SWOT analysis outcomes were used to determine several key factors to be implemented, including dedicated technicians solely assigned to the NHS program and purchase of new equipment to improve accuracy and reduce disposable costs. In addition, a two-tiered approach was implemented whereby the dedicated technicians performed initial screenings, with all rescreens performed by an audiologist. Results: Implementation of the new NHS program demonstrated numerous successes including a significant reduction in the failure rate, improved care coordination, and increased communication between ambulatory and hospital services

Coastal wetlands can be saved from sea level rise by recreating past tidal regimes

Climate change driven Sea Level Rise (SLR) is creating a major global environmental crisis in coastal ecosystems, however, limited practical solutions are provided to prevent or mitigate the impacts. Here, we propose a novel eco-engineering solution to protect highly valued vegetated intertidal ecosystems. The new ‘Tidal Replicate Method’ involves the creation of a synthetic tidal regime that mimics the desired hydroperiod for intertidal wetlands. This synthetic tidal regime can then be applied via automated tidal control systems, “SmartGates”, at suitable locations. As a proof of concept study, this method was applied at an intertidal wetland with the aim of restabilising saltmarsh vegetation at a location representative of SLR. Results from aerial drone surveys and on-ground vegetation sampling indicated that the Tidal Replicate Method effectively established saltmarsh onsite over a 3-year period of post-restoration, showing the method is able to protect endangered intertidal ecosystems from submersion. If applied globally, this method can protect high value coastal wetlands with similar environmental settings, including over 1,184,000 ha of Ramsar coastal wetlands. This equates to a saving of US$230 billion in ecosystem services per year. This solution can play an important role in the global effort to conserve coastal wetlands under accelerating SLR

qPCR screening for Yersinia ruckeri clonal complex 1 against a background of putatively avirulent strains in Norwegian aquaculture

Although a number of genetically diverse Yersinia ruckeri strains are present in Norwegian aquaculture environments, most if not all outbreaks of yersiniosis in Atlantic salmon in Norway are associated with a single specific genetic lineage of serotype O1, termed clonal complex 1. To investigate the presence and spread of virulent and putatively avirulent strains in Norwegian salmon farms, PCR assays specific for Y. ruckeri (species level) and Y. ruckeri clonal complex 1 were developed. Following extensive screening of water and biofilm, the widespread prevalence of putatively avirulent Y. ruckeri strains was confirmed in freshwater salmon hatcheries, while Y. ruckeri clonal complex 1 was found in fewer farms. The formalin-killed bacterin yersiniosis vaccine was detected in environmental samples by both PCR assays for several weeks post-vaccination. It is thus important to interpret results from recently vaccinated fish with great care. Moreover, field studies and laboratory trials confirmed that stressful management procedures may result in increased shedding of Y. ruckeri by sub-clinically infected fish. Analysis of sea water sampled throughout thermal delousing procedures proved effective for detection of Y. ruckeri in sub-clinically infected populations.publishedVersio

Genomic analysis of pasteurella atlantica provides insight on its virulence factors and phylogeny and highlights the potential of reverse vaccinology in aquaculture

Pasteurellosis in farmed lumpsuckers, Cyclopterus lumpus, has emerged as a serious disease in Norwegian aquaculture in recent years. Genomic characterization of the causative agent is essential in understanding the biology of the bacteria involved and in devising an efficient preventive strategy. The genomes of two clinical Pasteurella atlantica isolates were sequenced (≈2.3 Mbp), and phylogenetic analysis confirmed their position as a novel species within the Pasteurellaceae. In silico analyses revealed 11 genomic islands and 5 prophages, highlighting the potential of mobile elements as driving forces in the evolution of this species. The previously documented pathogenicity of P. atlantica is strongly supported by the current study, and 17 target genes were recognized as putative primary drivers of pathogenicity. The expression level of a predicted vaccine target, an uncharacterized adhesin protein, was significantly increased in both broth culture and following the exposure of P. atlantica to lumpsucker head kidney leucocytes. Based on in silico and functional analyses, the strongest gene target candidates will be prioritized in future vaccine development efforts to prevent future pasteurellosis outbreaks.publishedVersio

Molecular phylogeny of the Pectinoidea (Bivalvia) indicates Propeamussiidae to be a non-monophyletic family with one clade sister to the scallops (Pectinidae)

Scallops (Pectinidae) are one of the most diverse families of bivalves and have been a model system in evolutionary biology. However, in order to understand phenotypic evolution, the Pectinidae needs to be placed in a deeper phylogenetic framework within the superfamily Pectinoidea. We reconstructed a molecular phylogeny for 60 species from four of the five extant families within the Pectinoidea using a five gene dataset (12S, 16S, 18S, 28S rRNAs and histone H3). Our analyses give consistent support for the non-monophyly of the Propeamussiidae, with a subset of species as the sister group to the Pectinidae, the Propeamussiidae type species as sister to the Spondylidae, and the majority of propeamussiid taxa sister to the Spondylidae + Pr. dalli. This topology represents a previously undescribed relationship of pectinoidean families. Our results suggest a single origin for eyes within the superfamily and likely multiple instances of loss for these characters. However, it is now evident that reconstructing the evolutionary relationships of Pectinoidea will require a more comprehensive taxonomic sampling of the Propeamussiidae sensu lato

Geochronology of age-progressive volcanism of the Oregon High Lava Plains : implications for the plume interpretation of Yellowstone

The High Lava Plains province (HLP) is a late Cenozoic bimodal volcanic field at the northern margin of the Basin and Range province in southeastern Oregon that hosts a westward younging trend of silicic volcanism that crudely mirrors northeastward migration of silicic volcanism along the Yellowstone–Snake River Plain (YSRP) trend. We present ⁴⁰Ar/³⁹Ar ages for 19 rhyolite domes, 5 rhyolite ash flow tuffs, and 34 basaltic lavas from the HLP. The previously identified trend of westward migration of HLP rhyolites is confirmed. The rate of propagation is ∼33 km/m.y. from 10 to 5 Ma, slowing to ∼13 km/m.y. after 5 Ma. The duration of silicic volcanism at any locus is ∼2 m.y. Three older HLP dacite domes yielded ages of ∼15.5 Ma. Basalts are not age progressive. We identify several episodes of increased basaltic activity at 7.5–7.8, 5.3–5.9, and 2–3 Ma, with the younger episode likely continuing into the Recent. The HLP and YSRP trends emerged from the axis of middle Miocene basaltic volcanism of the Columbia River and Steens basalts. We propose a model in which (1) Miocene flood basalts and widespread silicic rocks are the result of emplacement of a plume head near the craton margin, enhanced by flow up a topographic gradient along the base of the lithosphere at the craton margin; (2) the HLP trend is the result of westward flow originating at the craton margin; and (3) the YSRP trend is the trace of the motion of the North American plate over the tail of the plume