Background Previous studies support a strong association between viral respiratory tract infections and asthma exacerbations. The effect of newly discovered viruses on asthma control is less well ...defined. Objective We sought to determine the contribution of respiratory viruses to asthma exacerbations in children with a panel of PCR assays for common and newly discovered respiratory viruses. Methods Respiratory specimens from children aged 2 to 17 years with asthma exacerbations (case patients, n = 65) and with well-controlled asthma (control subjects, n = 77), frequency matched by age and season of enrollment, were tested for rhinoviruses, enteroviruses, respiratory syncytial virus, human metapneumovirus, coronaviruses 229E and OC43, parainfluenza viruses 1 to 3, influenza viruses, adenoviruses, and human bocavirus. Results Infection with respiratory viruses was associated with asthma exacerbations (63.1% in case patients vs 23.4% in control subjects; odds ratio, 5.6; 95% CI, 2.7- 11.6). Rhinovirus was by far the most prevalent virus (60% among case patients vs 18.2% among control subjects) and the only virus significantly associated with exacerbations (odds ratio, 6.8; 95% CI, 3.2-14.5). However, in children without clinically manifested viral respiratory tract illness, the prevalence of rhinovirus infection was similar in case patients (29.2%) versus control subjects (23.4%, P > .05). Other viruses detected included human metapneumovirus (4.6% in patients with acute asthma vs 2.6% in control subjects), enteroviruses (4.6% vs 0%), coronavirus 229E (0% vs 1.3%), and respiratory syncytial virus (1.5% vs 0%). Conclusion Symptomatic rhinovirus infections are an important contributor to asthma exacerbations in children. Clinical implications These results support the need for therapies effective against rhinovirus as a means to decrease asthma exacerbations.
This paper focuses on energy-efficient packet transmission with individual packet delay constraints. The solution presented herein is a generalization of Uysal-Biyikoglu et al. (2002), which ...considered energy-efficient transmissions for a group of M packets subject to a single transmission deadline. First, the optimal offline scheduler (vis-a-vis total transmission energy) for packet transmissions with individual packet delay constraints is developed. It is shown that when packet inter-arrival times are independent and identically distributed (i.i.d.), the optimal transmission durations of packet m and packet M - m + 1, m isin 1,...,M, M ges 1, are identically distributed. This symmetry property leads to a simple and exact solution of the average packet delay for any i.i.d. inter-arrival times under the optimal offline scheduling. In addition, the packet delay performance for the single transmission deadline model is analyzed and shown to grow monotonically with M and at a rate proportional to radicM. A heuristic online scheduler, which assumes no future arrival information, is also studied and shown to achieve a comparable energy performance to the optimal offline scheduler in a wide range of scenarios. The flexible energy and delay tradeoff provided by the individual delay constraint model is further illustrated via simulations.
Summary In 2003 the American Association for Pediatric Ophthalmology and Strabismus Vision Screening Committee proposed criteria for automated preschool vision screening. Recent literature from ...epidemiologic and natural history studies, randomized controlled trials of amblyopia treatment, and field studies of screening technologies have been reviewed for the purpose of updating these criteria. The prevalence of amblyopia risk factors (ARF) is greater than previously suspected; many young children with low-magnitude ARFs do not develop amblyopia, and those who do often respond to spectacles alone. High-magnitude ARFs increase the likelihood of amblyopia. Although depth increases with age, amblyopia remains treatable until 60 months, with decline in treatment effectiveness after age 5. US Preventive Services Task Force Preventative Services Task Force guidelines allow photoscreening for children older than 36 months of age. Some technologies directly detect amblyopia rather than ARFs. Age-based criteria for ARF detection using photoscreening is prudent: referral criteria for such instruments should produce high specificity for ARF detection in young children and high sensitivity to detect amblyopia in older children. Refractive screening for ARFs for children aged 12-30 months should detect astigmatism >2.0 D, hyperopia >4.5 D, and anisometropia >2.5 D; for children aged 31-48 months, astigmatism >2.0 D, hyperopia > 4.0 D, and anisometropia >2.0 D. For children >49 months of age original criteria should be used: astigmatism >1.5 D, anisometropia>1.5 D, and hyperopia >3.5 D. Visually significant media opacities and manifest (not intermittent) strabismus should be detected at all ages. Instruments that detect amblyopia should report results using amblyopia presence as the gold standard. These new American Association for Pediatric Ophthalmology and Strabismus Vision Screening Committee guidelines will improve reporting of results and comparison of technologies.
Therapeutic drug monitoring (TDM) is a tool to personalize and optimize dosing by measuring the drug concentration and subsequently adjusting the dose to reach a target concentration or exposure. The ...evidence to support TDM is however often ranked as expert opinion. Limitations in study design and sample size have hampered definitive conclusions of the potential added value of TDM.
We aim to give expert opinion and discuss the main points and limitations of available data from antibiotic TDM trials and emphasize key elements for consideration in design of future clinical studies to quantify the benefits of TDM.
The sources were peer-reviewed publications, guidelines and expert opinions from the field of TDM.
This review focuses on key aspects of antimicrobial TDM study design: describing the rationale for a TDM study, assessing the exposure of a drug, assessing susceptibility of pathogens and selecting appropriate clinical endpoints. Moreover we provide guidance on appropriate study design.
This is an overview of different aspects relevant for the conduct of a TDM study. We believe that this paper will help researchers and clinicians to design and conduct high-quality TDM studies.
We experimentally realize a highly tunable superfluid oscillator circuit in a quantum gas of ultracold atoms and develop and verify a simple lumped-element description of this circuit. At low ...oscillator currents, we demonstrate that the circuit is accurately described as a Helmholtz resonator, a fundamental element of acoustic circuits. At larger currents, the breakdown of the Helmholtz regime is heralded by a turbulent shedding of vortices and density waves. Although a simple phase-slip model offers qualitative insights into the circuit's resistive behavior, our results indicate deviations from the phase-slip model. A full understanding of the dissipation in superfluid circuits will thus require the development of empirical models of the turbulent dynamics in this system, as have been developed for classical acoustic systems.
We present HST Faint Object Spectrograph spectra of the blazar 3C 279 obtained during two recent optical outbursts of this source, maximizing the sensitivity to weak foreground absorption systems at ...FUV wavelengths for this sight line. Eighteen absorption systems were detected above an observed 3 sigma limiting equivalent width of about 0.3 A. These systems include an unusual, partially thick Lyman limit + C IV + Mg II system at z(abs) = 0.395. In retrospect, this Lyman limit system was detected in the cumulative IUE SWP scan of 3C 279 but was not noted previously. The column density, redshift, location of the sight line 20/h kpc above the plane of an edge-on spiral galaxy, and apparent lack of velocity structure at 1 A resolution make this system an ideal candidate for a low-z measurement of the cosmic abundance of deuterium relative to hydrogen. Amazingly, this absorption system in 3C 279 (1253-055) differs by less than 100 km/s from the velocity of a known metal line/21 cm absorber in another quasar, PKS 1229-021 almost 7 deg away on the sky. The 3C 279 sight line also contains a time-variable absorber intrinsic to 3C 279 and a clump of four absorbers at z = 0.133-0.138. The 1996 epoch spectra, which immediately preceded a large flare at gamma- and X-ray energies, showed the line flux of Ly-alpha and N V emission in 3C 279 to be unchanged compared with an earlier epoch, despite a factor of four increase in the continuum emission level. (Author)
In forward testing effects, taking a test enhances memory for subsequently studied material. These effects have been observed for previously studied and tested items, a potentially item-specific ...testing effect, and newly studied untested items, a purely generalized testing effect. We directly compared item-specific and generalized forward testing effects using procedures to separate testing benefits due to encoding versus retrieval. Participants studied two lists of Swahili-English word pairs, with the second study list containing "new" pairs intermixed with the previously studied "old" pairs. Participants completed a review phase in which they took a cued-recall test on only the "old" pairs or restudied them. In Experiments 1a, 1b, and 2, the review phase was given either before or after the second study list. Testing benefited memory to the same degree for both "new" and "old" pairs, suggesting that there were no pair-specific benefits of testing. The larger benefit from testing when review was given before rather than after the second study list suggests that the memory enhancement was due to both testing-enhanced encoding and testing-enhanced retrieval. To better equate generalized testing effects for "new" and "old" pairs, Experiment 3 intermixed them in the review phase. A statistically significant pair-specific testing effect for "old" items was now observed. Overall, these results show that forward testing effects are due to both testing-enhanced encoding and retrieval effects and that direct, pair-specific forward testing benefits are considerably smaller than indirect, generalized forward testing benefits.
In the western United States, the long-term recovery of many Pacific salmon populations is inextricably linked to freshwater habitat quality. Industrial activities from the past century have left a ...legacy of pollutants that persist, particularly near working waterfronts. The adverse impacts of these contaminants on salmon health have been studied for decades, but the population-scale consequences of chemical exposure for salmonids are still poorly understood. We estimated acute and delayed mortality rates for seaward migrating juvenile Chinook salmon that feed and grow in a Superfund-designated area in the Lower Willamette River in Portland, Oregon. We combined previous, field-collected exposure data for juvenile Chinook salmon together with reduced growth and disease resistance data from earlier field and laboratory studies. Estimates of mortality were then incorporated into a life cycle model to explore chemical habitat-related fish loss. We found that 54% improved juvenile survival-potentially as a result of future remediation activities-could increase adult Chinook salmon population abundance by more than 20%. This study provides a framework for evaluating pollution remediation as a positive driver for species recovery.
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