1,069 research outputs found
Definition of a labelling code for the noise emitted by machines
It has been increasingly realised that traditional parameters, such as A-weighted sound levels, sound power and noise spectra in octaves or third octaves are not enough to describe a sound and that machine labels should show more subjective information about the emitted noise. A new labelling system based on empirical data is proposed. The methodology of the study used as the basis for the proposal is explained, as well as the objective and subjective characteristics to be included in the new label. The uses and applications of the label are discussed briefly
Depth of Field Analysis for Multilayer Automultiscopic Displays
With the re-emergence of stereoscopic displays, through polarized glasses for theatrical presentations and shuttered liquid crystal eyewear in the home, automultiscopic displays have received increased attention. Commercial efforts have predominantly focused on parallax barrier and lenticular architectures applied to LCD panels. Such designs suffer from reduced resolution and brightness. Recently, multilayer LCDs have emerged as an alternative supporting full-resolution imagery with enhanced brightness and depth of field. We present a signal-processing framework for comparing the depth of field for conventional automultiscopic displays and emerging architectures comprising multiple light-attenuating layers. We derive upper bounds for the depths of field, indicating the potential of multilayer configurations to significantly enhance resolution and depth of field, relative to conventional designs.Massachusetts Institute of Technology. Media LaboratoryMIT Camera Culture GroupNational Science Foundation (U.S.) (Grant IIS-1116452)United States. Defense Advanced Research Projects Agency. MOSAIC ProgramUnited States. Defense Advanced Research Projects Agency. SCENICC ProgramAlfred P. Sloan Foundation (Research Fellowship)United States. Defense Advanced Research Projects Agency. (Young Faculty Award
Binaural interaction and the octave illusion
The auditory octave illusion arises when dichotically presented tones, one octave apart, alternate rapidly between the ears. Most subjects perceive an illusory sequence of monaural tones: A high tone in the right ear (RE) alternates with a low tone, incorrectly localized to the left ear (LE). Behavioral studies suggest that the perceived pitch follows the RE input, and the perceived location the higher-frequency sound. To explore the link between the perceived pitches and brain-level interactions of dichotic tones, magnetoencephalographic responses were recorded to 4 binaural combinations of 2-min long continuous 400- and 800-Hz tones and to 4 monaural tones. Responses to LE and RE inputs were distinguished by frequency-tagging the ear-specific stimuli at different modulation frequencies. During dichotic presentation, ipsilateral LE tones elicited weaker and ipsilateral RE tones stronger responses than when both ears received the same tone. During the most paradoxical stimulus—high tone to LE and low tone to RE perceived as a low tone in LE during the illusion—also the contralateral responses to LE tones were diminished. The results demonstrate modified binaural interaction of dichotic tones one octave apart, suggesting that this interaction contributes to pitch perception during the octave illusion.Peer reviewe
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The Importance of Body Weight for the Dose Response Relationship of Oral Vitamin D Supplementation and Serum 25-Hydroxyvitamin D in Healthy Volunteers
Unlike vitamin D recommendations by the Institute of Medicine, the Clinical Practice Guidelines by the Endocrine Society acknowledge body weight differentials and recommend obese subjects be given two to three times more vitamin D to satisfy their body's vitamin D requirement. However, the Endocrine Society also acknowledges that there are no good studies that clearly justify this. In this study we examined the combined effect of vitamin D supplementation and body weight on serum 25-hydroxyvitamin (25(OH)D) and serum calcium in healthy volunteers. We analyzed 22,214 recordings of vitamin D supplement use and serum 25(OH)D from 17,614 healthy adult volunteers participating in a preventive health program. This program encourages the use of vitamin D supplementation and monitors its use and serum 25(OH)D and serum calcium levels. Participants reported vitamin D supplementation ranging from 0 to 55,000 IU per day and had serum 25(OH)D levels ranging from 10.1 to 394 nmol/L. The dose response relationship between vitamin D supplementation and serum 25(OH)D followed an exponential curve. On average, serum 25(OH)D increased by 12.0 nmol/L per 1,000 IU in the supplementation interval of 0 to 1,000 IU per day and by 1.1 nmol/L per 1,000 IU in the supplementation interval of 15,000 to 20,000 IU per day. BMI, relative to absolute body weight, was found to be the better determinant of 25(OH)D. Relative to normal weight subjects, obese and overweight participants had serum 25(OH)D that were on average 19.8 nmol/L and 8.0 nmol/L lower, respectively (P<0.001). We did not observe any increase in the risk for hypercalcemia with increasing vitamin D supplementation. We recommend vitamin D supplementation be 2 to 3 times higher for obese subjects and 1.5 times higher for overweight subjects relative to normal weight subjects. This observational study provides body weight specific recommendations to achieve 25(OH)D targets
Fusion In The Era Of Burning Plasma Studies: Workforce Planning For 2004-2014
This is the final report of a panel set up by the U.S. Department of Energy (DOE) Fusion Energy Sciences Advisory Committee (FESAC) in response to a charge letter from Dr. Raymond Orbach (Appendix A), asking FESAC to addressed the issue of workforce development in the U.S. fusion program. This report, submitted to FESAC March 29, 2004 and subsequently approved by them (Appendix B), presents FESAC\u27s response to that charge
Robust circadian clocks from coupled protein modification and transcription-translation cycles
The cyanobacterium Synechococcus elongatus uses both a protein
phosphorylation cycle and a transcription-translation cycle to generate
circadian rhythms that are highly robust against biochemical noise. We use
stochastic simulations to analyze how these cycles interact to generate stable
rhythms in growing, dividing cells. We find that a protein phosphorylation
cycle by itself is robust when protein turnover is low. For high decay or
dilution rates (and co mpensating synthesis rate), however, the
phosphorylation-based oscillator loses its integrity. Circadian rhythms thus
cannot be generated with a phosphorylation cycle alone when the growth rate,
and consequently the rate of protein dilution, is high enough; in practice, a
purely post-translational clock ceases to function well when the cell doubling
time drops below the 24 hour clock period. At higher growth rates, a
transcription-translation cycle becomes essential for generating robust
circadian rhythms. Interestingly, while a transcription-translation cycle is
necessary to sustain a phosphorylation cycle at high growth rates, a
phosphorylation cycle can dramatically enhance the robustness of a
transcription-translation cycle at lower protein decay or dilution rates. Our
analysis thus predicts that both cycles are required to generate robust
circadian rhythms over the full range of growth conditions.Comment: main text: 7 pages including 5 figures, supplementary information: 13
pages including 9 figure
Investigating Perceptual Congruence Between Data and Display Dimensions in Sonification
The relationships between sounds and their perceived meaning and connotations are complex, making auditory perception an important factor to consider when designing sonification systems. Listeners often have a mental model of how a data variable should sound during sonification and this model is not considered in most data:sound mappings. This can lead to mappings that are difficult to use and can cause confusion. To investigate this issue, we conducted a magnitude estimation experiment to map how roughness, noise and pitch relate to the perceived magnitude of stress, error and danger. These parameters were chosen due to previous findings which suggest perceptual congruency between these auditory sensations and conceptual variables. Results from this experiment show that polarity and scaling preference are dependent on the data:sound mapping. This work provides polarity and scaling values that may be directly utilised by sonification designers to improve auditory displays in areas such as accessible and mobile computing, process-monitoring and biofeedback
D-fence Against the Canadian Winter: Making Insufficient Vitamin D Levels a Higher Priority for Public Health
With most of the country situated above the latitude of the 42nd parallel north, there is a significant portion of the Canadian population that is not getting enough of the sunshine vitamin during the winter. Vitamin D is naturally produced when skin is exposed to sunlight, however during the winter months in Canada the sun is too low in the sky for this to occur. A full quarter of the Canadian population is estimated to have vitamin D levels so low as to be considered insufficient or deficient by Health Canada guidelines. Increasing vitamin D intake should be considered a public health priority. Vitamin D deficiency is known to be linked to rickets in children and osteomalacia in adults (bone softening and malformation) as well as osteoporosis (loss of bone density, increasing susceptibility to fractures). However a growing body of evidence also suggests that vitamin D may have a role in the prevention of chronic diseases such as heart disease, high blood pressure, diabetes, cancer, cognitive decline, Parkinson’s disease, multiple sclerosis and arthritis. There is, of course, no way to change Canada’s proximity to the equator. But there are ways to help Canadians get more vitamin D through dietary intake. Improving the vitamin D status of the Canadian population through food fortification and dietary supplements represents an inexpensive intervention that can improve the health of the population, but debate remains over how much vitamin D the Canadian population needs and how to ensure the population adheres to whatever recommendations are made. Food fortification has already demonstrated its effectiveness in improving vitamin D levels (as it has for other public health priorities, such as with iodized salt). Decades ago, the prevalence of rickets in Canadian children led health professionals to lobby for, and win, legislation making vitamin D fortification mandatory for milk. Other foods, such as orange juice, milk of plant origin and margarine are sometimes also fortified with vitamin D. However many Canadians do not consume milk or the other fortified foods or do not take dietary supplements at the current recommended levels, increasing their risk of vitamin D insufficiency. It is clear there is a need to gain a better understanding of the benefits and the costs of strategies associated with vitamin D intake in the general population. There have been longstanding concerns about the risk of people consuming too much vitamin D (leading to hypercalcemia). More recently there has emerged great disagreement in the scientific and regulatory communities over what constitutes an excessive dosage of vitamin D, and even what constitutes the optimal blood-serum level for vitamin D. The inability to settle on firm guidelines is paralyzing any movement towards increasing vitamin D intake in the Canadian population. Fortification and public health strategies are needed to ensure current vitamin D targets are met. Health Canada’s proposal to allow greater levels of vitamins and minerals to be added to foods, to meet consumer demand (within maximum limits), has been on the table since 2005. A decade later, the Canadian winters have grown no shorter, and the solar zenith angle has not changed. It is becoming an increasingly urgent matter of public health to reach a consensus on updated guidelines for vitamin D intake levels and limits, to better inform Canadians
SPARTAN: a global network to evaluate and enhance satellite-based estimates of ground-level particulate matter for global health applications
Ground-based observations have insufficient spatial coverage to assess long-term human exposure to fine particulate matter (PM2.5) at the global scale. Satellite remote sensing offers a promising approach to provide information on both short-and long-term exposure to PM2.5 at local-to-global scales, but there are limitations and outstanding questions about the accuracy and precision with which ground-level aerosol mass concentrations can be inferred from satellite remote sensing alone. A key source of uncertainty is the global distribution of the relationship between annual average PM2.5 and discontinuous satellite observations of columnar aerosol optical depth (AOD). We have initiated a global network of ground-level monitoring stations designed to evaluate and enhance satellite remote sensing estimates for application in health-effects research and risk assessment. This Surface PARTiculate mAtter Network (SPARTAN) includes a global federation of ground-level monitors of hourly PM2.5 situated primarily in highly populated regions and collocated with existing ground-based sun photometers that measure AOD. The instruments, a three-wavelength nephelometer and impaction filter sampler for both PM2.5 and PM10, are highly autonomous. Hourly PM2.5 concentrations are inferred from the combination of weighed filters and nephelometer data. Data from existing networks were used to develop and evaluate network sampling characteristics. SPARTAN filters are analyzed for mass, black carbon, water-soluble ions, and metals. These measurements provide, in a variety of regions around the world, the key data required to evaluate and enhance satellite-based PM2.5 estimates used for assessing the health effects of aerosols. Mean PM2.5 concentrations across sites vary by more than 1 order of magnitude. Our initial measurements indicate that the ratio of AOD to ground-level PM2.5 is driven temporally and spatially by the vertical profile in aerosol scattering. Spatially this ratio is also strongly influenced by the mass scattering efficiency.Fil: Snider, G.. Dalhousie University Halifax; CanadáFil: Weagle, C. L.. Dalhousie University Halifax; CanadáFil: Martin, R. V.. Dalhousie University Halifax; Canadá. University of Cambridge; Reino UnidoFil: van Donkelaar, A.. Dalhousie University Halifax; CanadáFil: Conrad, K.. Dalhousie University Halifax; CanadáFil: Cunningham, D.. Dalhousie University Halifax; CanadáFil: Gordon, C.. Dalhousie University Halifax; CanadáFil: Zwicker, M.. Dalhousie University Halifax; CanadáFil: Akoshile, C.. University of Ilorin; NigeriaFil: Artaxo, P.. Governo Do Estado de Sao Paulo; BrasilFil: Anh, N. X.. Vietnam Academy of Science and Technology. Institute of Geophysics; VietnamFil: Brook, J.. University of Toronto; CanadáFil: Dong, J.. Tsinghua University; ChinaFil: Garland, R. M.. North-West University; SudáfricaFil: Greenwald, R.. Rollins School of Public Health; Estados UnidosFil: Griffith, D.. Council for Scientific and Industrial Research; SudáfricaFil: He, K.. Tsinghua University; ChinaFil: Holben, B. N.. NASA Goddard Space Flight Center; Estados UnidosFil: Kahn, R.. NASA Goddard Space Flight Center; Estados UnidosFil: Koren, I.. Weizmann Institute Of Science Israel; IsraelFil: Lagrosas, N.. Manila Observatory, Ateneo de Manila University campus; FilipinasFil: Lestari, P.. Institut Teknologi Bandung; IndonesiaFil: Ma, Z.. Rollins School of Public Health; Estados UnidosFil: Vanderlei Martins, J.. University of Maryland; Estados UnidosFil: Quel, Eduardo Jaime. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rudich, Y.. Weizmann Institute Of Science Israel; IsraelFil: Salam, A.. University Of Dhaka; BangladeshFil: Tripathi, S. N.. Indian Institute Of Technology, Kanpur; IndiaFil: Yu, C.. Rollins School of Public Health; Estados UnidosFil: Zhang, Q.. Tsinghua University; ChinaFil: Zhang, Y.. Tsinghua University; ChinaFil: Brauer, M.. University of British Columbia; CanadáFil: Cohen, A.. Health Effects Institute; Estados UnidosFil: Gibson, M. D.. Dalhousie University Halifax; CanadáFil: Liu, Y.. Rollins School of Public Health; Estados Unido
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