10 research outputs found
Pediatric Deaths Due to Otolaryngologic Causes: A Population‐Based Study in Massachusetts, 1990–2002
No full textSafety of the HyperSound® Audio System in subjects with normal hearing
No full textThe objective of the study was to assess the safety of the HyperSound® Audio System (HSS), a novel audio system using ultrasound technology, in normal hearing subjects under normal use conditions; we considered preexposure and post-exposure test design. We investigated primary and secondary outcome measures: i) temporary threshold shift (TTS), defined as >10 dB shift in pure tone air conduction thresholds and/or a decrement in distortion product otoacoustic emissions (DPOAEs) >10 dB at two or more frequencies; ii) presence of new-onset otologic symptoms after exposure. Twenty adult subjects with normal hearing underwent a pre-exposure assessment (pure tone air conduction audiometry, tympanometry, DPOAEs and otologic symptoms questionnaire) followed by exposure to a 2-h movie with sound delivered through the HSS emitter followed by a post-exposure assessment. No TTS or new-onset otological symptoms were identified. HSS demonstrates excellent safety in normal hearing subjects under normal use conditions
Determinants of Hearing Loss in Perforations of the Tympanic Membrane
No full textBackground: Although tympanic membrane perforations are common, there have been few systematic studies of the structural features determining the magnitude of the resulting conductive hearing loss. Our recent experimental and modeling studies predicted that the conductive hearing loss will increase with increasing perforation size, be independent of perforation location (contrary to popular otologic belief), and increase with decreasing size of the middle-ear and mastoid air space (an idea new to otology).
Objective: To test our predictions regarding determinants of conductive hearing loss in tympanic membrane perforations against clinical data gathered from patients.
Study Design: Prospective clinical study. Setting: Tertiary referral center.
Inclusion Criteria: Patients with tympanic membrane perforations without other middle-ear disease. Main Outcome Measures: Size and location of perforation; air-bone gap at 250, 500, 1,000, 2,000, and 4,000 Hz; and tympanometric estimate of volume of the middle-ear air spaces.
Results: Isolated tympanic membrane perforations in 62 ears from 56 patients met inclusion criteria. Air-bone gaps were largest at the lower frequencies and decreased as frequency increased. Air-bone gaps increased with perforation size at each frequency. Ears with small middle-ear volumes, ≤4.3 ml (n = 23), had significantly larger air-bone gaps than ears with large middle-ear volumes, \u3e4.3 ml (n = 39), except at 2,000 Hz. The mean air-bone gaps in ears with small volumes were 10 to 20 dB larger than in ears with large volumes. Perforations in anterior versus posterior quadrants showed no significant differences in air-bone gaps at any frequency, although anterior perforations had, on average, air-bone gaps that were smaller by 1 to 8 dB at lower frequencies.
Conclusion: The conductive hearing loss resulting from a tympanic membrane perforation is frequency-dependent, with the largest losses occurring at the lowest sound frequencies; increases as size of the perforation increases; varies inversely with volume of the middle-ear and mastoid air space (losses are larger in ears with small volumes); and does not vary appreciably with location of the perforation. Effects of location, if any, are small
Efficacy of Early Neonatal Vitamin A Supplementation in Reducing Mortality During Infancy in Ghana, India and Tanzania: Study Protocol for a Randomized Controlled Trial.
No full textVitamin A supplementation of 6-59 month old children is currently recommended by the World Health Organization based on evidence that it reduces mortality. There has been considerable interest in determining the benefits of neonatal vitamin A supplementation, but the results of existing trials are conflicting. A technical consultation convened by WHO pointed to the need for larger scale studies in Asia and Africa to inform global policy on the use of neonatal vitamin A supplementation. Three trials were therefore initiated in Ghana, India and Tanzania to determine if vitamin A supplementation (50,000 IU) given to neonates once orally on the day of birth or within the next two days will reduce mortality in the period from supplementation to 6 months of age compared to placebo. The trials are individually randomized, double masked, and placebo controlled. The required sample size is 40,200 in India and 32,000 each in Ghana and Tanzania. The study participants are neonates who fulfil age eligibility, whose families are likely to stay in the study area for the next 6 months, who are able to feed orally, and whose parent(s) provide informed written consent to participate in the study. Neonates randomized to the intervention group receive 50,000 IU vitamin A and the ones randomized to the control group receive placebo at the time of enrollment. Mortality and morbidity information are collected through periodic home visits by a study worker during infancy. The primary outcome of the study is mortality from supplementation to 6 months of age. The secondary outcome of the study is mortality from supplementation to 12 months of age. The three studies will be analysed independent of each other. Subgroup analysis will be carried out to determine the effect by birth weight, sex, and timing of DTP vaccine, socioeconomic groups and maternal large-dose vitamin A supplementation. The three ongoing studies are the largest studies evaluating the efficacy of vitamin A supplementation to neonates. Policy formulation will be based on the results of efficacy of the intervention from the ongoing randomized controlled trials combined with results of previous studies
Assessing the impacts of 1.5 °C global warming – simulation protocol of the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP2b)
No full textIn Paris, France, December 2015, the Conference of the Parties (COP) to the
United Nations Framework Convention on Climate Change (UNFCCC) invited the
Intergovernmental Panel on Climate Change (IPCC) to provide a special
report in 2018 on the impacts of global warming of 1.5 °C
above pre-industrial levels and related global greenhouse gas emission
pathways. In Nairobi, Kenya, April 2016, the IPCC panel accepted the
invitation. Here we describe the response devised within the Inter-Sectoral
Impact Model Intercomparison Project (ISIMIP) to provide tailored,
cross-sectorally consistent impact projections to broaden the scientific
basis for the report. The simulation protocol is designed to allow for (1) separation of the impacts of historical warming starting from pre-industrial
conditions from impacts of other drivers such as historical land-use changes
(based on pre-industrial and historical impact model simulations); (2) quantification
of the impacts of additional warming up to 1.5 °C, including a potential overshoot and long-term impacts up to 2299, and
comparison to higher levels of global mean temperature change (based on the
low-emissions Representative Concentration Pathway RCP2.6 and a no-mitigation
pathway RCP6.0) with socio-economic conditions fixed at 2005 levels; and (3) assessment
of the climate effects based on the same climate scenarios while
accounting for simultaneous changes in socio-economic conditions following
the middle-of-the-road Shared Socioeconomic Pathway
(SSP2, Fricko et al., 2016) and in particular
differential bioenergy requirements associated with the transformation of
the energy system to comply with RCP2.6 compared to RCP6.0. With the aim of
providing the scientific basis for an aggregation of impacts across sectors
and analysis of cross-sectoral interactions that may dampen or amplify
sectoral impacts, the protocol is designed to facilitate consistent impact
projections from a range of impact models across different sectors (global
and regional hydrology, lakes, global crops, global vegetation, regional
forests, global and regional marine ecosystems and fisheries, global and
regional coastal infrastructure, energy supply and demand,
temperature-related mortality, and global terrestrial biodiversity)
Harmonization of global land use change and management for the period 850–2100 (LUH2) for CMIP6
No full textHuman land use activities have resulted in large changes to the biogeochemical and biophysical properties of the Earth's surface, with consequences for climate and other ecosystem services. In the future, land use activities are likely to expand and/or intensify further to meet growing demands for food, fiber, and energy. As part of the World Climate Research Program Coupled Model Intercomparison Project (CMIP6), the international community has developed the next generation of advanced Earth system models (ESMs) to estimate the combined effects of human activities (e.g., land use and fossil fuel emissions) on the carbon-climate system. A new set of historical data based on the History of the Global Environment database (HYDE), and multiple alternative scenarios of the future (2015-2100) from Integrated Assessment Model (IAM) teams, is required as input for these models. With most ESM simulations for CMIP6 now completed, it is important to document the land use patterns used by those simulations. Here we present results from the Land-Use Harmonization 2 (LUH2) project, which smoothly connects updated historical reconstructions of land use with eight new future projections in the format required for ESMs. The harmonization strategy estimates the fractional land use patterns, underlying land use transitions, key agricultural management information, and resulting secondary lands annually, while minimizing the differences between the end of the historical reconstruction and IAM initial conditions and preserving changes depicted by the IAMs in the future. The new approach builds on a similar effort from CMIP5 and is now provided at higher resolution (0.25◦ × 0.25◦) over a longer time domain (850-2100, with extensions to 2300) with more detail (including multiple crop and pasture types and associated management practices) using more input datasets (including Landsat remote sensing data) and updated algorithms (wood harvest and shifting cultivation); it is assessed via a new diagnostic package. The new LUH2 products contain > 50 times the information content of the datasets used in CMIP5 and are designed to enable new and improved estimates of the combined effects of land use on the global carbon-climate system. © Author(s) 2020. This work is distributed under the Creative Commons Attribution 4.0 License
