Identification of a threshold for biomass exposure index for chronic bronchitis in rural women of Mysore district, Karnataka, India.

PubMed

Mahesh, P A; Jayaraj, B S; Prabhakar, A K; Chaya, S K; Vijaysimha, R

2013-01-01

Exposure to air pollution due to combustion of biomass fuels remains one of the significant risk factors for chronic respiratory diseases such as chronic bronchitis. There is a need to identify the minimum threshold level of biomass index that is significantly associated with chronic bronchitis. This study was undertaken to identify a threshold for biomass exposure index in a rural women population in Mysore district, south India. A cross-sectional survey was conducted in a representative population of Mysore and Nanjangud taluks. Eight villages each from Mysore and Nanjangud were randomly selected based on the list of villages from census 2001. A house-to-house survey was carried out by trained field workers using the Burden of Obstructive Diseases questionnaire, which evaluated the biomass smoke exposure and chronic bronchitis. All the women aged above 30 yr were included in the study. A total of 2011 women from Mysore and 1942 women from Nanjangud participated in the study. All women were non-smoking and used biomass fuels as the primary fuel for cooking. A threshold of biomass fuel exposure of 60 was identified on multivariate analysis in Mysore district after adjusting for age, passive smoking and working in a occupational exposure to dust, as the minimum required for a significant association with chronic bronchitis. One in every 20 women in Mysore district exposed to biomass fuel exposure index of 110 or more developed chronic bronchitis. The minimum threshold of biomass exposure index of 60 is necessary to have a significant risk of developing chronic bronchitis in women. The number needed to harm to develop chronic bronchitis reduces with increasing biomass exposure index and women residing in rural Nanjangud have a higher risk for developing chronic bronchitis as compared to women in Mysore.

Establishing storm thresholds for the Spanish Gulf of Cádiz coast

NASA Astrophysics Data System (ADS)

Del Río, Laura; Plomaritis, Theocharis A.; Benavente, Javier; Valladares, María; Ribera, Pedro

2012-03-01

In this study critical thresholds are defined for storm impacts along the Spanish coast of the Gulf of Cádiz. The thresholds correspond to the minimum wave and tide conditions necessary to produce significant morphological changes on beaches and dunes and/or damage on coastal infrastructure or human occupation. Threshold definition was performed by computing theoretical sea-level variations during storms and comparing them with the topography of the study area and the location of infrastructure at a local level. Specifically, the elevations of the berm, the dune foot and the entrance of existing washovers were selected as threshold parameters. The total sea-level variation generated by a storm event was estimated as the sum of the tidal level, the wind-induced setup, the barometric setup and the wave-associated sea-level variation (wave setup and runup), assuming a minimum interaction between the different processes. These components were calculated on the basis of parameterisations for significant wave height (Hs) obtained for the oceanographic and environmental conditions of the Gulf of Cadiz. For this purpose real data and reanalysis time-series (HIPOCAS project) were used. Validation of the obtained results was performed for a range of coastal settings over the study area. The obtained thresholds for beach morphological changes in spring tide conditions range between a significant wave height of 1.5 m and 3.7 m depending on beach characteristics, while for dune foot erosion are around 3.3 to 3.7 m and for damage to infrastructure around 7.2 m. In case of neap tide conditions these values are increased on average by 50% over the areas with large tidal range. Furthermore, records of real damage in coastal infrastructure caused by storms were collected at a regional level from newspapers and other bibliographic sources and compared with the hydrodynamic conditions that caused the damage. These were extracted from the hindcast database of the HIPOCAS project, including parameters such as storm duration, mean and maximum wave height and wave direction. Results show that the duration of the storm is not critical in determining the occurrence of coastal damage in the regional study area. This way, the threshold would be defined as a duration ≥30 h, with moderate average wave height (≥3.3 m) and high maximum wave height (≥4.1 m) approaching from the 3rd and 4th quadrants, during mean or spring tide situation. The calculated thresholds constitute snapshots of risk conditions within a certain time framework. Beach and nearshore zones are extremely dynamic, and also the characteristics of occupation on the coast change over time, so critical storm thresholds will change accordingly and therefore will need to be updated.

Nonlinear distortion analysis for single heterojunction GaAs HEMT with frequency and temperature

NASA Astrophysics Data System (ADS)

Alim, Mohammad A.; Ali, Mayahsa M.; Rezazadeh, Ali A.

2018-07-01

Nonlinearity analysis using two-tone intermodulation distortion (IMD) technique for 0.5 μm gate-length AlGaAs/GaAs based high electron mobility transistor have been investigated based on biasing conditions, input power, frequency and temperature. The outcomes indicate a significant modification on the output IMD power and as well as the minimum distortion level. The input IMD power effects the output current and subsequently the threshold voltage reduces, resulting to an increment in the output IMD power. Both frequency and temperature reduces the magnitude of the output IMDs. In addition, the threshold voltage response with temperature alters the notch point of the nonlinear output IMD’s accordingly. The aforementioned investigation will help the circuit designers to evaluate the best biasing option in terms of minimum distortion, maximum gain for future design optimizations.

Research on critical groundwater level under the threshold value of land subsidence in the typical region of Beijing

NASA Astrophysics Data System (ADS)

Jiang, Y.; Liu, J.-R.; Luo, Y.; Yang, Y.; Tian, F.; Lei, K.-C.

2015-11-01

Groundwater in Beijing has been excessively exploited in a long time, causing the groundwater level continued to declining and land subsidence areas expanding, which restrained the economic and social sustainable development. Long years of study show good time-space corresponding relationship between groundwater level and land subsidence. To providing scientific basis for the following land subsidence prevention and treatment, quantitative research between groundwater level and settlement is necessary. Multi-linear regression models are set up by long series factual monitoring data about layered water table and settlement in the Tianzhu monitoring station. The results show that: layered settlement is closely related to water table, water level variation and amplitude, especially the water table. Finally, according to the threshold value in the land subsidence prevention and control plan of China (45, 30, 25 mm), the minimum allowable layered water level in this region while settlement achieving the threshold value is calculated between -18.448 and -10.082 m. The results provide a reasonable and operable control target of groundwater level for rational adjustment of groundwater exploited horizon in the future.

Phosphene Perception Relates to Visual Cortex Glutamate Levels and Covaries with Atypical Visuospatial Awareness.

PubMed

Terhune, Devin B; Murray, Elizabeth; Near, Jamie; Stagg, Charlotte J; Cowey, Alan; Cohen Kadosh, Roi

2015-11-01

Phosphenes are illusory visual percepts produced by the application of transcranial magnetic stimulation to occipital cortex. Phosphene thresholds, the minimum stimulation intensity required to reliably produce phosphenes, are widely used as an index of cortical excitability. However, the neural basis of phosphene thresholds and their relationship to individual differences in visual cognition are poorly understood. Here, we investigated the neurochemical basis of phosphene perception by measuring basal GABA and glutamate levels in primary visual cortex using magnetic resonance spectroscopy. We further examined whether phosphene thresholds would relate to the visuospatial phenomenology of grapheme-color synesthesia, a condition characterized by atypical binding and involuntary color photisms. Phosphene thresholds negatively correlated with glutamate concentrations in visual cortex, with lower thresholds associated with elevated glutamate. This relationship was robust, present in both controls and synesthetes, and exhibited neurochemical, topographic, and threshold specificity. Projector synesthetes, who experience color photisms as spatially colocalized with inducing graphemes, displayed lower phosphene thresholds than associator synesthetes, who experience photisms as internal images, with both exhibiting lower thresholds than controls. These results suggest that phosphene perception is driven by interindividual variation in glutamatergic activity in primary visual cortex and relates to cortical processes underlying individual differences in visuospatial awareness. © The Author 2015. Published by Oxford University Press.

No minimum threshold for ozone-induced changes in soybean canopy fluxes

USDA-ARS?s Scientific Manuscript database

Tropospheric ozone concentrations [O3] are increasing at rates that exceed any other pollutant. This highly reactive gas drives reductions in plant productivity and canopy water use while also increasing canopy temperature and sensible heat flux. It is not clear whether a minimum threshold of ozone ...

Evaluation of nuclear chromatin using grayscale intensity and thresholded percentage area in liquid-based cervical cytology.

PubMed

Lee, Hyekyung; Han, Myungein; Yoo, Taejo; Jung, Chanho; Son, Hyun-Jin; Cho, Migyung

2018-05-01

Development of computerized image analysis techniques has opened up the possibility for the quantitative analysis of nuclear chromatin in pathology. We hypothesized that the features extracted from digital images could be used to determine specific cytomorphological findings for nuclear chromatin that may be applicable for establishing a medical diagnosis. Three parameters were evaluated from nuclear chromatin images obtained from the liquid-based cervical cytology samples of patients with biopsy-proven high-grade squamous intraepithelial lesion (HGSIL), and compared between non-neoplastic squamous epithelia and dysplastic epithelia groups: (1) standard deviation (SD) of the grayscale intensity; (2) difference between the maximum and minimum grayscale intensity (M-M); and (3) thresholded area percentage. Each parameter was evaluated at the mean, mean-1SD, and mean-2SD thresholding intensity levels. Between the mean and mean-1SD levels, the thresholded nuclear chromatin pattern was most similar to the chromatin granularity of the unthresholded grayscale images. The SD of the gray intensity and the thresholded area percentage differed significantly between the non-neoplastic squamous epithelia and dysplastic epithelia of HGSIL images at all three thresholding intensity levels (mean, mean-1SD, and mean-2SD). However, the M-M significantly differed between the two sample types for only two of the thresholding intensity levels (mean-1SD and mean-2SD). The digital parameters SD and M-M of the grayscale intensity, along with the thresholded area percentage could be useful in automated cytological evaluations. Further studies are needed to identify more valuable parameters for clinical application. © 2018 Wiley Periodicals, Inc.

Projections for Achieving the Lancet Commission Recommended Surgical Rate of 5000 Operations per 100,000 Population by Region-Specific Surgical Rate Estimates.

PubMed

Uribe-Leitz, Tarsicio; Esquivel, Micaela M; Molina, George; Lipsitz, Stuart R; Verguet, Stéphane; Rose, John; Bickler, Stephen W; Gawande, Atul A; Haynes, Alex B; Weiser, Thomas G

2015-09-01

We previously identified a range of 4344-5028 annual operations per 100,000 people to be related to desirable health outcomes. From this and other evidence, the Lancet Commission on Global Surgery recommends a minimum rate of 5000 operations per 100,000 people. We evaluate rates of growth and estimate the time it will take to reach this minimum surgical rate threshold. We aggregated country-level surgical rate estimates from 2004 to 2012 into the twenty-one Global Burden of Disease (GBD) regions. We calculated mean rates of surgery proportional to population size for each year and assessed the rate of growth over time. We then extrapolated the time it will take each region to reach a surgical rate of 5000 operations per 100,000 population based on linear rates of change. All but two regions experienced growth in their surgical rates during the past 8 years. Fourteen regions did not meet the recommended threshold in 2012. If surgical capacity continues to grow at current rates, seven regions will not meet the threshold by 2035. Eastern Sub-Saharan Africa will not reach the recommended threshold until 2124. The rates of growth in surgical service delivery are exceedingly variable. At current rates of surgical and population growth, 6.2 billion people (73% of the world's population) will be living in countries below the minimum recommended rate of surgical care in 2035. A strategy for strengthening surgical capacity is essential if these targets are to be met in a timely fashion as part of the integrated health system development.

Effects of arc current on the life in burner rig thermal cycling of plasma sprayed ZrOsub2-Ysub2Osub3

NASA Technical Reports Server (NTRS)

Hendricks, R. C.; Mcdonald, G.

1982-01-01

An analysis of thermal cycle life data for four sets of eight thermal barrier coated specimens representing arc currents (plasma gun power) of 525, 600, 800, or 950 amps is presented. The ZrO2-8Y2O3/NiCrAlY plasma spray coated Rene 41 rods were thermal cycled to 1040 C in a Mach 0.3-Jet A/air burner flame. The experimental results indicate the existance of a minimum or threshold power level which coating life expectancy is less than 500 cycles. Above the threshold power level, coating life expectancy more than doubles and increases with arc current.

Effects of arc current on the life in burner rig thermal cycling of plasma sprayed ZrOsub2-Ysub2Osub3

NASA Astrophysics Data System (ADS)

Hendricks, R. C.; McDonald, G.

1982-02-01

An analysis of thermal cycle life data for four sets of eight thermal barrier coated specimens representing arc currents (plasma gun power) of 525, 600, 800, or 950 amps is presented. The ZrO2-8Y2O3/NiCrAlY plasma spray coated Rene 41 rods were thermal cycled to 1040 C in a Mach 0.3-Jet A/air burner flame. The experimental results indicate the existance of a minimum or threshold power level which coating life expectancy is less than 500 cycles. Above the threshold power level, coating life expectancy more than doubles and increases with arc current.

Rainfall thresholds as a landslide indicator for engineered slopes on the Irish Rail network

NASA Astrophysics Data System (ADS)

Martinović, Karlo; Gavin, Kenneth; Reale, Cormac; Mangan, Cathal

2018-04-01

Rainfall thresholds express the minimum levels of rainfall that need to be reached or exceeded in order for landslides to occur in a particular area. They are a common tool in expressing the temporal portion of landslide hazard analysis. Numerous rainfall thresholds have been developed for different areas worldwide, however none of these are focused on landslides occurring on the engineered slopes on transport infrastructure networks. This paper uses empirical method to develop the rainfall thresholds for landslides on the Irish Rail network earthworks. For comparison, rainfall thresholds are also developed for natural terrain in Ireland. The results show that particular thresholds involving relatively low rainfall intensities are applicable for Ireland, owing to the specific climate. Furthermore, the comparison shows that rainfall thresholds for engineered slopes are lower than those for landslides occurring on the natural terrain. This has severe implications as it indicates that there is a significant risk involved when using generic weather alerts (developed largely for natural terrain) for infrastructure management, and showcases the need for developing railway and road specific rainfall thresholds for landslides.

Effect of a preventive vaccine on the dynamics of HIV transmission

NASA Astrophysics Data System (ADS)

Gumel, A. B.; Moghadas, S. M.; Mickens, R. E.

2004-12-01

A deterministic mathematical model for the transmission dynamics of HIV infection in the presence of a preventive vaccine is considered. Although the equilibria of the model could not be expressed in closed form, their existence and threshold conditions for their stability are theoretically investigated. It is shown that the disease-free equilibrium is locally-asymptotically stable if the basic reproductive number R<1 (thus, HIV disease can be eradicated from the community) and unstable if R>1 (leading to the persistence of HIV within the community). A robust, positivity-preserving, non-standard finite-difference method is constructed and used to solve the model equations. In addition to showing that the anti-HIV vaccine coverage level and the vaccine-induced protection are critically important in reducing the threshold quantity R, our study predicts the minimum threshold values of vaccine coverage and efficacy levels needed to eradicate HIV from the community.

Relationships between host viremia and vector susceptibility for arboviruses.

PubMed

Lord, Cynthia C; Rutledge, C Roxanne; Tabachnick, Walter J

2006-05-01

Using a threshold model where a minimum level of host viremia is necessary to infect vectors affects our assessment of the relative importance of different host species in the transmission and spread of these pathogens. Other models may be more accurate descriptions of the relationship between host viremia and vector infection. Under the threshold model, the intensity and duration of the viremia above the threshold level is critical in determining the potential numbers of infected mosquitoes. A probabilistic model relating host viremia to the probability distribution of virions in the mosquito bloodmeal shows that the threshold model will underestimate the significance of hosts with low viremias. A probabilistic model that includes avian mortality shows that the maximum number of mosquitoes is infected by feeding on hosts whose viremia peaks just below the lethal level. The relationship between host viremia and vector infection is complex, and there is little experimental information to determine the most accurate model for different arthropod-vector-host systems. Until there is more information, the ability to distinguish the relative importance of different hosts in infecting vectors will remain problematic. Relying on assumptions with little support may result in erroneous conclusions about the importance of different hosts.

Relationships Between Host Viremia and Vector Susceptibility for Arboviruses

PubMed Central

Lord, Cynthia C.; Rutledge, C. Roxanne; Tabachnick, Walter J.

2010-01-01

Using a threshold model where a minimum level of host viremia is necessary to infect vectors affects our assessment of the relative importance of different host species in the transmission and spread of these pathogens. Other models may be more accurate descriptions of the relationship between host viremia and vector infection. Under the threshold model, the intensity and duration of the viremia above the threshold level is critical in determining the potential numbers of infected mosquitoes. A probabilistic model relating host viremia to the probability distribution of virions in the mosquito bloodmeal shows that the threshold model will underestimate the significance of hosts with low viremias. A probabilistic model that includes avian mortality shows that the maximum number of mosquitoes is infected by feeding on hosts whose viremia peaks just below the lethal level. The relationship between host viremia and vector infection is complex, and there is little experimental information to determine the most accurate model for different arthropod–vector–host systems. Until there is more information, the ability to distinguish the relative importance of different hosts in infecting vectors will remain problematic. Relying on assumptions with little support may result in erroneous conclusions about the importance of different hosts. PMID:16739425

Analysis of Intelligence and Academic Scores as a Predictor of Promotion Rate for U.S. Army Noncommissioned Officers.

DTIC Science & Technology

1987-07-06

levels of intellegence tests and academic background as values to predict promotion. The model, however, demonstrated only limited utility as a preditive...attributes in the form of promotion points or a minimum threshold scale would be one approach. Unfortunately, this may artificially force NCO’s of less

Value of information and pricing new healthcare interventions.

PubMed

Willan, Andrew R; Eckermann, Simon

2012-06-01

Previous application of value-of-information methods to optimal clinical trial design have predominantly taken a societal decision-making perspective, implicitly assuming that healthcare costs are covered through public expenditure and trial research is funded by government or donation-based philanthropic agencies. In this paper, we consider the interaction between interrelated perspectives of a societal decision maker (e.g. the National Institute for Health and Clinical Excellence [NICE] in the UK) charged with the responsibility for approving new health interventions for reimbursement and the company that holds the patent for a new intervention. We establish optimal decision making from societal and company perspectives, allowing for trade-offs between the value and cost of research and the price of the new intervention. Given the current level of evidence, there exists a maximum (threshold) price acceptable to the decision maker. Submission for approval with prices above this threshold will be refused. Given the current level of evidence and the decision maker's threshold price, there exists a minimum (threshold) price acceptable to the company. If the decision maker's threshold price exceeds the company's, then current evidence is sufficient since any price between the thresholds is acceptable to both. On the other hand, if the decision maker's threshold price is lower than the company's, then no price is acceptable to both and the company's optimal strategy is to commission additional research. The methods are illustrated using a recent example from the literature.

Passive blast pressure sensor

DOEpatents

King, Michael J.; Sanchez, Roberto J.; Moss, William C.

2013-03-19

A passive blast pressure sensor for detecting blast overpressures of at least a predetermined minimum threshold pressure. The blast pressure sensor includes a piston-cylinder arrangement with one end of the piston having a detection surface exposed to a blast event monitored medium through one end of the cylinder and the other end of the piston having a striker surface positioned to impact a contact stress sensitive film that is positioned against a strike surface of a rigid body, such as a backing plate. The contact stress sensitive film is of a type which changes color in response to at least a predetermined minimum contact stress which is defined as a product of the predetermined minimum threshold pressure and an amplification factor of the piston. In this manner, a color change in the film arising from impact of the piston accelerated by a blast event provides visual indication that a blast overpressure encountered from the blast event was not less than the predetermined minimum threshold pressure.

Using generalized additive modeling to empirically identify thresholds within the ITERS in relation to toddlers' cognitive development.

PubMed

Setodji, Claude Messan; Le, Vi-Nhuan; Schaack, Diana

2013-04-01

Research linking high-quality child care programs and children's cognitive development has contributed to the growing popularity of child care quality benchmarking efforts such as quality rating and improvement systems (QRIS). Consequently, there has been an increased interest in and a need for approaches to identifying thresholds, or cutpoints, in the child care quality measures used in these benchmarking efforts that differentiate between different levels of children's cognitive functioning. To date, research has provided little guidance to policymakers as to where these thresholds should be set. Using the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B) data set, this study explores the use of generalized additive modeling (GAM) as a method of identifying thresholds on the Infant/Toddler Environment Rating Scale (ITERS) in relation to toddlers' performance on the Mental Development subscale of the Bayley Scales of Infant Development (the Bayley Mental Development Scale Short Form-Research Edition, or BMDSF-R). The present findings suggest that simple linear models do not always correctly depict the relationships between ITERS scores and BMDSF-R scores and that GAM-derived thresholds were more effective at differentiating among children's performance levels on the BMDSF-R. Additionally, the present findings suggest that there is a minimum threshold on the ITERS that must be exceeded before significant improvements in children's cognitive development can be expected. There may also be a ceiling threshold on the ITERS, such that beyond a certain level, only marginal increases in children's BMDSF-R scores are observed. (PsycINFO Database Record (c) 2013 APA, all rights reserved).

Effects of programming threshold and maplaw settings on acoustic thresholds and speech discrimination with the MED-EL COMBI 40+ cochlear implant.

PubMed

Boyd, Paul J

2006-12-01

The principal task in the programming of a cochlear implant (CI) speech processor is the setting of the electrical dynamic range (output) for each electrode, to ensure that a comfortable loudness percept is obtained for a range of input levels. This typically involves separate psychophysical measurement of electrical threshold ([theta] e) and upper tolerance levels using short current bursts generated by the fitting software. Anecdotal clinical experience and some experimental studies suggest that the measurement of [theta]e is relatively unimportant and that the setting of upper tolerance limits is more critical for processor programming. The present study aims to test this hypothesis and examines in detail how acoustic thresholds and speech recognition are affected by setting of the lower limit of the output ("Programming threshold" or "PT") to understand better the influence of this parameter and how it interacts with certain other programming parameters. Test programs (maps) were generated with PT set to artificially high and low values and tested on users of the MED-EL COMBI 40+ CI system. Acoustic thresholds and speech recognition scores (sentence tests) were measured for each of the test maps. Acoustic thresholds were also measured using maps with a range of output compression functions ("maplaws"). In addition, subjective reports were recorded regarding the presence of "background threshold stimulation" which is occasionally reported by CI users if PT is set to relatively high values when using the CIS strategy. Manipulation of PT was found to have very little effect. Setting PT to minimum produced a mean 5 dB (S.D. = 6.25) increase in acoustic thresholds, relative to thresholds with PT set normally, and had no statistically significant effect on speech recognition scores on a sentence test. On the other hand, maplaw setting was found to have a significant effect on acoustic thresholds (raised as maplaw is made more linear), which provides some theoretical explanation as to why PT has little effect when using the default maplaw of c = 500. Subjective reports of background threshold stimulation showed that most users could perceive a relatively loud auditory percept, in the absence of microphone input, when PT was set to double the behaviorally measured electrical thresholds ([theta]e), but that this produced little intrusion when microphone input was present. The results of these investigations have direct clinical relevance, showing that setting of PT is indeed relatively unimportant in terms of speech discrimination, but that it is worth ensuring that PT is not set excessively high, as this can produce distracting background stimulation. Indeed, it may even be set to minimum values without deleterious effect.

Final comprehensive report of overall activities of AEC contract AT(30-1)- 3269 from its initiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1973-01-01

Research accomplishments are reported for the following projects: determination of the minimum level of x radiation in rats to alter the taste threshold; determination of the permanency of such alteration; determination of the dose and time dependency of the alteration; changes in hypothalamic function following low doses of ionizing radiation; development of new behavioral technique for determination of taste thresholds; correlation of taste sensitivity changes with alteration in taste bud morphology; effects of olfaction on taste thresholds; properties of taste material that influence x radiation effects on taste; determination of effects of in utero x-irradiation on taste function in themore » adult rat; and effects of ingestion of heavy metals on taste acuity and response of taste sensitivity to x radiation. (HLW)« less

Effects of encapsulation damping on the excitation threshold for subharmonic generation from contrast microbubbles.

PubMed

Katiyar, Amit; Sarkar, Kausik

2012-11-01

A recent study [Katiyar and Sarkar (2011). J. Acoust. Soc. Am. 130, 3137-3147] showed that in contrast to the analytical result for free bubbles, the minimum threshold for subharmonic generation for contrast microbubbles does not necessarily occur at twice the resonance frequency. Here increased damping-either due to the small radius or the encapsulation-is shown to shift the minimum threshold away from twice the resonance frequency. Free bubbles as well as four models of the contrast agent encapsulation are investigated varying the surface dilatational viscosity. Encapsulation properties are determined using measured attenuation data for a commercial contrast agent. For sufficiently small damping, models predict two minima for the threshold curve-one at twice the resonance frequency being lower than the other at resonance frequency-in accord with the classical analytical result. However, increased damping damps the bubble response more at twice the resonance than at resonance, leading to a flattening of the threshold curve and a gradual shift of the absolute minimum from twice the resonance frequency toward the resonance frequency. The deviation from the classical result stems from the fact that the perturbation analysis employed to obtain it assumes small damping, not always applicable for contrast microbubbles.

Benefit adequacy among elderly Social Security retired-worker beneficiaries and the SSI federal benefit rate.

PubMed

Rupp, Kalman; Strand, Alexander; Davies, Paul; Sears, Jim

2007-01-01

Both target effectiveness and administrative simplicity are desirable properties in the design of minimum benefit packages for public retirement programs. The federal benefit rate (FBR) of the Supplemental Security Income (SSI) program has been proposed by some analysts as a potentially attractive basis of establishing a new minimum benefit for Social Security on both of these grounds. This type of proposal is related to a broader array of minimum benefit proposals that would establish a Social Security benefit floor based on the poverty rate. In contrast to Social Security, the SSI program is means tested, including both an income and asset screen and also a categorical eligibility screen (the requirement to qualify as aged or disabled). The SSI FBR provides an inflation-adjusted, guaranteed income floor for aged and disabled people with low assets. The FBR has been perceived by proponents as a minimal measure of Social Security benefit adequacy because it represents a subpoverty income level for a family of one or two depending on marital status. For this same reason it has been seen as a target-effective tool of designing a minimum Social Security benefit. An FBR-based minimum benefit has also been viewed as administratively simple to implement; the benefit can be calculated from Social Security administrative records using a completely automated electronic process. Therefore-in contrast to the SSI program itself-an FBR-based minimum benefit would incur virtually no ongoing administrative costs, would not require a separate application for a means-tested program, and would avoid the perception of welfare stigma. While these ideas have been discussed in the literature and among policymakers in the United States over the years, and similar proposals have been considered or implemented in several foreign countries, there have been no previous analyses measuring the size of the potentially affected beneficiary population. Nor has there been any systematic assessment of the FBR as a measure of benefit adequacy or the tradeoffs between potential target effectiveness and administrative simplicity. Based on a series of simulations, we assess the FBR as a potential foundation for minimum Social Security benefits and we examine the tradeoffs between administrative simplicity and target effectiveness using microdata from the 1996 panel of the Survey of Income and Program Participation (SIPP). Our empirical analysis is limited to Social Security retired-worker beneficiaries aged 65 or older. We start with the assessment of the FBR as a measure of benefit adequacy. We are particularly concerned about two types of error: (1) incorrectly identifying some Social Security beneficiaries as "economically vulnerable," and (2) incorrectly identifying others as "not economically vulnerable." Operationally we measure economic vulnerability by two alternative standards. One of our measures considers beneficiaries with family income below the official poverty threshold as vulnerable. Our second measure is more restrictive; it uses a family income threshold equal to 75 percent of the official poverty threshold. We find that a substantial minority of retired workers have Social Security benefits below the FBR. The results also show that the FBR-based measure of Social Security benefit adequacy is very imprecise in terms of identifying economically vulnerable people. We estimate that the vast majority of beneficiaries with Social Security benefits below the FBR are not economically vulnerable. Conversely, an FBR-level Social Security benefit threshold fails to identify some beneficiaries who are economically vulnerable. Thus an FBR-level minimum benefit would be poorly targeted in terms of both types of errors we are concerned about. An FBR-level minimum benefit would provide minimum Social Security benefits to many people who are clearly not poor. Conversely, an FBR-level minimum benefit would not provide any income relief to some who are poor. The administrative simplicity behind these screening errors also results in additional program cost that may be perceived as substantial. We estimate that an FBR-level minimum benefit would increase aggregate program cost for retired workers aged 65 or older by roughly 2 percent. There are two fundamental reasons for these findings. First, the concept of an FBR-level minimum benefit looks at the individual or married couple in artificial isolation; however, the family is the main consumption unit in our society. The income of an unmarried partner or family members other than a married spouse is ignored. Second, individuals and couples may also have income from sources other than Social Security or SSI, which is also ignored by a simple FBR-based minimum benefit concept. The substantial empirical magnitude of measurement error arising from these conceptual simplifications naturally leads to the assessment of the tradeoff between target effectiveness and administrative simplicity. To facilitate this analysis, we simulate the potential effect of alternative screening methods designed to increase target effectiveness; while reducing program cost, such alternatives also may increase administrative complexity. For example, considering the combined Social Security benefit of a married couple (rather than looking at the husband and wife in isolation) might substantially increase target effectiveness with a relatively small increase in administrative complexity. Adding a family income screen might increase administrative complexity to a greater degree, but also would increase target effectiveness dramatically. The results also suggest that at some point adding new screens-such as a comprehensive asset test-may drastically increase administrative complexity with diminishing returns in terms of increased target effectiveness and reduced program cost. Whether a broad-based minimum benefit concept that is not tied to previous work experience is perceived by policymakers as desirable or not may depend on several factors not addressed in this article. However, to the extent that this type of minimum benefit design is regarded as potentially desirable, the tradeoffs between administrative simplicity and target effectiveness need to be considered.

Protograph LDPC Codes with Node Degrees at Least 3

NASA Technical Reports Server (NTRS)

Divsalar, Dariush; Jones, Christopher

2006-01-01

In this paper we present protograph codes with a small number of degree-3 nodes and one high degree node. The iterative decoding threshold for proposed rate 1/2 codes are lower, by about 0.2 dB, than the best known irregular LDPC codes with degree at least 3. The main motivation is to gain linear minimum distance to achieve low error floor. Also to construct rate-compatible protograph-based LDPC codes for fixed block length that simultaneously achieves low iterative decoding threshold and linear minimum distance. We start with a rate 1/2 protograph LDPC code with degree-3 nodes and one high degree node. Higher rate codes are obtained by connecting check nodes with degree-2 non-transmitted nodes. This is equivalent to constraint combining in the protograph. The condition where all constraints are combined corresponds to the highest rate code. This constraint must be connected to nodes of degree at least three for the graph to have linear minimum distance. Thus having node degree at least 3 for rate 1/2 guarantees linear minimum distance property to be preserved for higher rates. Through examples we show that the iterative decoding threshold as low as 0.544 dB can be achieved for small protographs with node degrees at least three. A family of low- to high-rate codes with minimum distance linearly increasing in block size and with capacity-approaching performance thresholds is presented. FPGA simulation results for a few example codes show that the proposed codes perform as predicted.

Application of threshold concepts to ecological management problems: occupancy of Golden Eagles in Denali National Park, Alaska: Chapter 5

USGS Publications Warehouse

Eaton, Mitchell J.; Martin, Julien; Nichols, James D.; McIntyre, Carol; McCluskie, Maggie C.; Schmutz, Joel A.; Lubow, Bruce L.; Runge, Michael C.; Edited by Guntenspergen, Glenn R.

2014-01-01

In this chapter, we demonstrate the application of the various classes of thresholds, detailed in earlier chapters and elsewhere, via an actual but simplified natural resource management case study. We intend our example to provide the reader with the ability to recognize and apply the theoretical concepts of utility, ecological and decision thresholds to management problems through a formalized decision-analytic process. Our case study concerns the management of human recreational activities in Alaska’s Denali National Park, USA, and the possible impacts of such activities on nesting Golden Eagles, Aquila chrysaetos. Managers desire to allow visitors the greatest amount of access to park lands, provided that eagle nesting-site occupancy is maintained at a level determined to be acceptable by the managers themselves. As these two management objectives are potentially at odds, we treat minimum desired occupancy level as a utility threshold which, then, serves to guide the selection of annual management alternatives in the decision process. As human disturbance is not the only factor influencing eagle occupancy, we model nesting-site dynamics as a function of both disturbance and prey availability. We incorporate uncertainty in these dynamics by considering several hypotheses, including a hypothesis that site occupancy is affected only at a threshold level of prey abundance (i.e., an ecological threshold effect). By considering competing management objectives and accounting for two forms of thresholds in the decision process, we are able to determine the optimal number of annual nesting-site restrictions that will produce the greatest long-term benefits for both eagles and humans. Setting a utility threshold of 75 occupied sites, out of a total of 90 potential nesting sites, the optimization specified a decision threshold at approximately 80 occupied sites. At the point that current occupancy falls below 80 sites, the recommended decision is to begin restricting access to humans; above this level, it is recommended that all eagle territories be opened to human recreation. We evaluated the sensitivity of the decision threshold to uncertainty in system dynamics and to management objectives (i.e., to the utility threshold).

A simple Bayesian approach to quantifying confidence level of adverse event incidence proportion in small samples.

PubMed

Liu, Fang

2016-01-01

In both clinical development and post-marketing of a new therapy or a new treatment, incidence of an adverse event (AE) is always a concern. When sample sizes are small, large sample-based inferential approaches on an AE incidence proportion in a certain time period no longer apply. In this brief discussion, we introduce a simple Bayesian framework to quantify, in small sample studies and the rare AE case, (1) the confidence level that the incidence proportion of a particular AE p is over or below a threshold, (2) the lower or upper bounds on p with a certain level of confidence, and (3) the minimum required number of patients with an AE before we can be certain that p surpasses a specific threshold, or the maximum allowable number of patients with an AE after which we can no longer be certain that p is below a certain threshold, given a certain confidence level. The method is easy to understand and implement; the interpretation of the results is intuitive. This article also demonstrates the usefulness of simple Bayesian concepts when it comes to answering practical questions.

Leisure time physical activity and mortality: a detailed pooled analysis of the dose-response relationship.

PubMed

Arem, Hannah; Moore, Steven C; Patel, Alpa; Hartge, Patricia; Berrington de Gonzalez, Amy; Visvanathan, Kala; Campbell, Peter T; Freedman, Michal; Weiderpass, Elisabete; Adami, Hans Olov; Linet, Martha S; Lee, I-Min; Matthews, Charles E

2015-06-01

The 2008 Physical Activity Guidelines for Americans recommended a minimum of 75 vigorous-intensity or 150 moderate-intensity minutes per week (7.5 metabolic-equivalent hours per week) of aerobic activity for substantial health benefit and suggested additional benefits by doing more than double this amount. However, the upper limit of longevity benefit or possible harm with more physical activity is unclear. To quantify the dose-response association between leisure time physical activity and mortality and define the upper limit of benefit or harm associated with increased levels of physical activity. We pooled data from 6 studies in the National Cancer Institute Cohort Consortium (baseline 1992-2003). Population-based prospective cohorts in the United States and Europe with self-reported physical activity were analyzed in 2014. A total of 661,137 men and women (median age, 62 years; range, 21-98 years) and 116,686 deaths were included. We used Cox proportional hazards regression with cohort stratification to generate multivariable-adjusted hazard ratios (HRs) and 95% CIs. Median follow-up time was 14.2 years. Leisure time moderate- to vigorous-intensity physical activity. The upper limit of mortality benefit from high levels of leisure time physical activity. Compared with individuals reporting no leisure time physical activity, we observed a 20% lower mortality risk among those performing less than the recommended minimum of 7.5 metabolic-equivalent hours per week (HR, 0.80 [95% CI, 0.78-0.82]), a 31% lower risk at 1 to 2 times the recommended minimum (HR, 0.69 [95% CI, 0.67-0.70]), and a 37% lower risk at 2 to 3 times the minimum (HR, 0.63 [95% CI, 0.62-0.65]). An upper threshold for mortality benefit occurred at 3 to 5 times the physical activity recommendation (HR, 0.61 [95% CI, 0.59-0.62]); however, compared with the recommended minimum, the additional benefit was modest (31% vs 39%). There was no evidence of harm at 10 or more times the recommended minimum (HR, 0.69 [95% CI, 0.59-0.78]). A similar dose-response relationship was observed for mortality due to cardiovascular disease and to cancer. Meeting the 2008 Physical Activity Guidelines for Americans minimum by either moderate- or vigorous-intensity activities was associated with nearly the maximum longevity benefit. We observed a benefit threshold at approximately 3 to 5 times the recommended leisure time physical activity minimum and no excess risk at 10 or more times the minimum. In regard to mortality, health care professionals should encourage inactive adults to perform leisure time physical activity and do not need to discourage adults who already participate in high-activity levels.

Method to improve reliability of a fuel cell system using low performance cell detection at low power operation

DOEpatents

Choi, Tayoung; Ganapathy, Sriram; Jung, Jaehak; Savage, David R.; Lakshmanan, Balasubramanian; Vecasey, Pamela M.

2013-04-16

A system and method for detecting a low performing cell in a fuel cell stack using measured cell voltages. The method includes determining that the fuel cell stack is running, the stack coolant temperature is above a certain temperature and the stack current density is within a relatively low power range. The method further includes calculating the average cell voltage, and determining whether the difference between the average cell voltage and the minimum cell voltage is greater than a predetermined threshold. If the difference between the average cell voltage and the minimum cell voltage is greater than the predetermined threshold and the minimum cell voltage is less than another predetermined threshold, then the method increments a low performing cell timer. A ratio of the low performing cell timer and a system run timer is calculated to identify a low performing cell.

Eccentric muscle damage has variable effects on motor unit recruitment thresholds and discharge patterns in elbow flexor muscles.

PubMed

Dartnall, Tamara J; Rogasch, Nigel C; Nordstrom, Michael A; Semmler, John G

2009-07-01

The purpose of this study was to determine the effect of eccentric muscle damage on recruitment threshold force and repetitive discharge properties of low-threshold motor units. Ten subjects performed four tasks involving isometric contraction of elbow flexors while electromyographic (EMG) data were recorded from human biceps brachii and brachialis muscles. Tasks were 1) maximum voluntary contraction (MVC); 2) constant-force contraction at various submaximal targets; 3) motor unit recruitment threshold task; and 4) minimum motor unit discharge rate task. These tasks were performed on three separate days before, immediately after, and 24 h after eccentric exercise of elbow flexor muscles. MVC force declined (42%) immediately after exercise and remained depressed (29%) 24 h later, indicative of muscle damage. Mean motor unit recruitment threshold for biceps brachii was 8.4+/-4.2% MVC, (n=34) before eccentric exercise, and was reduced by 41% (5.0+/-3.0% MVC, n=34) immediately after and by 39% (5.2+/-2.5% MVC, n=34) 24 h after exercise. No significant changes in motor unit recruitment threshold were observed in the brachialis muscle. However, for the minimum tonic discharge rate task, motor units in both muscles discharged 11% faster (10.8+/-2.0 vs. 9.7+/-1.7 Hz) immediately after (n=29) exercise compared with that before (n=32). The minimum discharge rate variability was greater in brachialis muscle immediately after exercise (13.8+/-3.1%) compared with that before (11.9+/-3.1%) and 24 h after exercise (11.7+/-2.4%). No significant changes in minimum discharge rate variability were observed in the biceps brachii motor units after exercise. These results indicate that muscle damage from eccentric exercise alters motor unit recruitment thresholds for >or=24 h, but the effect is not the same in the different elbow flexor muscles.

Estimation of Optimum Stimulus Amplitude for Balance Training using Electrical Stimulation of the Vestibular System

NASA Technical Reports Server (NTRS)

Goel, R.; Rosenberg, M. J.; De Dios, Y. E.; Cohen, H. S.; Bloomberg, J. J.; Mulavara, A. P.

2016-01-01

Sensorimotor changes such as posture and gait instabilities can affect the functional performance of astronauts after gravitational transitions. Sensorimotor Adaptability (SA) training can help alleviate decrements on exposure to novel sensorimotor environments based on the concept of 'learning to learn' by exposure to varying sensory challenges during posture and locomotion tasks (Bloomberg 2015). Supra-threshold Stochastic Vestibular Stimulation (SVS) can be used to provide one of many challenges by disrupting vestibular inputs. In this scenario, the central nervous system can be trained to utilize veridical information from other sensory inputs, such as vision and somatosensory inputs, for posture and locomotion control. The minimum amplitude of SVS to simulate the effect of deterioration in vestibular inputs for preflight training or for evaluating vestibular contribution in functional tests in general, however, has not yet been identified. Few studies (MacDougall 2006; Dilda 2014) have used arbitrary but fixed maximum current amplitudes from 3 to 5 mA in the medio-lateral (ML) direction to disrupt balance function in healthy adults. Giving this high level of current amplitude to all the individuals has a risk of invoking side effects such as nausea and discomfort. The goal of this study was to determine the minimum SVS level that yields an equivalently degraded balance performance. Thirteen subjects stood on a compliant foam surface with their eyes closed and were instructed to maintain a stable upright stance. Measures of stability of the head, trunk, and whole body were quantified in the ML direction. Duration of time they could stand on the foam surface was also measured. The minimum SVS dosage was defined to be that level which significantly degraded balance performance such that any further increase in stimulation level did not lead to further balance degradation. The minimum SVS level was determined by performing linear fits on the performance variable at different stimulation levels. Results from the balance task suggest that there are inter-individual differences and the minimum SVS amplitude was found to be in the range of 1 mA to 2.5 mA across subjects. SVS resulted in an average decrement of balance task performance in the range of 62%-73% across different measured variables at the minimum SVS amplitude in comparison to the control trial (no stimulus). Training using supra-threshold SVS stimulation is one of the sensory challenges used for preflight SA training designed to improve adaptability to novel gravitational environments. Inter-individual differences in response to SVS can help customize the SA training paradigms using minimal dosage required. Another application of using SVS is to simulate acute deterioration of vestibular sensory inputs in the evaluation of tests for assessing vestibular function.

Low Voltage Electrowetting-on-Dielectric Platform using Multi-Layer Insulators

PubMed Central

Lin, Yan-You; Evans, Randall D.; Welch, Erin; Hsu, Bang-Ning; Madison, Andrew C.; Fair, Richard B.

2010-01-01

A low voltage, two-level-metal, and multi-layer insulator electrowetting-on-dielectric (EWD) platform is presented. Dispensing 300pl droplets from 140nl closed on-chip reservoirs was accomplished with as little as 11.4V solely through EWD forces, and the actuation threshold voltage was 7.2V with a 1Hz voltage switching rate between electrodes. EWD devices were fabricated with a multilayer insulator consisting of 135nm sputtered tantalum pentoxide (Ta2O5) and 180nm parylene C coated with 70nm of CYTOP. Furthermore, the minimum actuation threshold voltage followed a previously published scaling model for the threshold voltage, VT, which is proportional to (t/εr)1/2, where t and εr are the insulator thickness and dielectric constant respectively. Device threshold voltages are compared for several insulator thicknesses (200nm, 500nm, and 1µm), different dielectric materials (parylene C and tantalum pentoxide), and homogeneous versus heterogeneous compositions. Additionally, we used a two-level-metal fabrication process, which enables the fabrication of smaller and denser electrodes with high interconnect routing flexibility. We also have achieved low dispensing and actuation voltages for scaled devices with 30pl droplets. PMID:20953362

A novel threshold criterion in transcranial motor evoked potentials during surgery for gliomas close to the motor pathway.

PubMed

Abboud, Tammam; Schaper, Miriam; Dührsen, Lasse; Schwarz, Cindy; Schmidt, Nils Ole; Westphal, Manfred; Martens, Tobias

2016-10-01

OBJECTIVE Warning criteria for monitoring of motor evoked potentials (MEP) after direct cortical stimulation during surgery for supratentorial tumors have been well described. However, little is known about the value of MEP after transcranial electrical stimulation (TES) in predicting postoperative motor deficit when monitoring threshold level. The authors aimed to evaluate the feasibility and value of this method in glioma surgery by using a new approach for interpreting changes in threshold level involving contra- and ipsilateral MEP. METHODS Between November 2013 and December 2014, 93 patients underwent TES-MEP monitoring during resection of gliomas located close to central motor pathways but not involving the primary motor cortex. The MEP were elicited by transcranial repetitive anodal train stimulation. Bilateral MEP were continuously evaluated to assess percentage increase of threshold level (minimum voltage needed to evoke a stable motor response from each of the muscles being monitored) from the baseline set before dural opening. An increase in threshold level on the contralateral side (facial, arm, or leg muscles contralateral to the affected hemisphere) of more than 20% beyond the percentage increase on the ipsilateral side (facial, arm, or leg muscles ipsilateral to the affected hemisphere) was considered a significant alteration. Recorded alterations were subsequently correlated with postoperative neurological deterioration and MRI findings. RESULTS TES-MEP could be elicited in all patients, including those with recurrent glioma (31 patients) and preoperative paresis (20 patients). Five of 73 patients without preoperative paresis showed a significant increase in threshold level, and all of them developed new paresis postoperatively (transient in 4 patients and permanent in 1 patient). Eight of 20 patients with preoperative paresis showed a significant increase in threshold level, and all of them developed postoperative neurological deterioration (transient in 4 patients and permanent in 4 patients). In 80 patients no significant change in threshold level was detected, and none of them showed postoperative neurological deterioration. The specificity and sensitivity in this series were estimated at 100%. Postoperative MRI revealed gross-total tumor resection in 56 of 82 patients (68%) in whom complete tumor resection was attainable; territorial ischemia was detected in 4 patients. CONCLUSIONS The novel threshold criterion has made TES-MEP a useful method for predicting postoperative motor deficit in patients who undergo glioma surgery, and has been feasible in patients with preoperative paresis as well as in patients with recurrent glioma. Including contra- and ipsilateral changes in threshold level has led to a high sensitivity and specificity.

Self-Tuning Threshold Method for Real-Time Gait Phase Detection Based on Ground Contact Forces Using FSRs.

PubMed

Tang, Jing; Zheng, Jianbin; Wang, Yang; Yu, Lie; Zhan, Enqi; Song, Qiuzhi

2018-02-06

This paper presents a novel methodology for detecting the gait phase of human walking on level ground. The previous threshold method (TM) sets a threshold to divide the ground contact forces (GCFs) into on-ground and off-ground states. However, the previous methods for gait phase detection demonstrate no adaptability to different people and different walking speeds. Therefore, this paper presents a self-tuning triple threshold algorithm (STTTA) that calculates adjustable thresholds to adapt to human walking. Two force sensitive resistors (FSRs) were placed on the ball and heel to measure GCFs. Three thresholds (i.e., high-threshold, middle-threshold andlow-threshold) were used to search out the maximum and minimum GCFs for the self-adjustments of thresholds. The high-threshold was the main threshold used to divide the GCFs into on-ground and off-ground statuses. Then, the gait phases were obtained through the gait phase detection algorithm (GPDA), which provides the rules that determine calculations for STTTA. Finally, the STTTA reliability is determined by comparing the results between STTTA and Mariani method referenced as the timing analysis module (TAM) and Lopez-Meyer methods. Experimental results show that the proposed method can be used to detect gait phases in real time and obtain high reliability when compared with the previous methods in the literature. In addition, the proposed method exhibits strong adaptability to different wearers walking at different walking speeds.

Oxygen Concentration Flammability Threshold Tests for the Constellation Program

NASA Technical Reports Server (NTRS)

Williams, James H.

2007-01-01

CEV atmosphere will likely change because craft will be used as LEO spacecraft, lunar spacecraft, orbital spacecraft. Possible O2 % increase and overall pressure decrease pressure vessel certs on spacecraft. Want 34% minimum threshold. Higher, better when atmosphere changes. WSTF suggests testing all materials/components to find flammability threshold, pressure and atmosphere.

Optimizing drug-dose alerts using commercial software throughout an integrated health care system.

PubMed

Saiyed, Salim M; Greco, Peter J; Fernandes, Glenn; Kaelber, David C

2017-11-01

All default electronic health record and drug reference database vendor drug-dose alerting recommendations (single dose, daily dose, dose frequency, and dose duration) were silently turned on in inpatient, outpatient, and emergency department areas for pediatric-only and nonpediatric-only populations. Drug-dose alerts were evaluated during a 3-month period. Drug-dose alerts fired on 12% of orders (104 098/834 911). System-level and drug-specific strategies to decrease drug-dose alerts were analyzed. System-level strategies included: (1) turning off all minimum drug-dosing alerts, (2) turning off all incomplete information drug-dosing alerts, (3) increasing the maximum single-dose drug-dose alert threshold to 125%, (4) increasing the daily dose maximum drug-dose alert threshold to 125%, and (5) increasing the dose frequency drug-dose alert threshold to more than 2 doses per day above initial threshold. Drug-specific strategies included changing drug-specific maximum single and maximum daily drug-dose alerting parameters for the top 22 drug categories by alert frequency. System-level approaches decreased alerting to 5% (46 988/834 911) and drug-specific approaches decreased alerts to 3% (25 455/834 911). Drug-dose alerts varied between care settings and patient populations. © The Author 2017. Published by Oxford University Press on behalf of the American Medical Informatics Association. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Minimum change in spherical aberration that can be perceived

PubMed Central

Manzanera, Silvestre; Artal, Pablo

2016-01-01

It is important to know the visual sensitivity to optical blur from both a basic science perspective and a practical point of view. Of particular interest is the sensitivity to blur induced by spherical aberration because it is being used to increase depth of focus as a component of a presbyopic solution. Using a flicker detection-based procedure implemented on an adaptive optics visual simulator, we measured the spherical aberration thresholds that produce just-noticeable differences in perceived image quality. The thresholds were measured for positive and negative values of spherical aberration, for best focus and + 0.5 D and + 1.0 D of defocus. At best focus, the SA thresholds were 0.20 ± 0.01 µm and −0.17 ± 0.03 µm for positive and negative spherical aberration respectively (referred to a 6-mm pupil). These experimental values may be useful in setting spherical aberration permissible levels in different ophthalmic techniques. PMID:27699113

Quantitative comparison of the results obtained by the multiple-dose guinea pig maximization test and the non-radioactive murine local lymph-node assay for various biocides.

PubMed

Yamano, Tetsuo; Shimizu, Mitsuru; Noda, Tsutomu

2005-07-01

We compared the results of the multiple-dose guinea pig maximization test (GPMT) and the non-radioactive murine local lymph-node assay (LLNA) for various biocides. Thirteen out of 17 positive biocides in the GPMT gave positive results in the LLNA. In the GPMT, the minimum first induction doses ranged over four orders (0.00005-0.5%), while elicitation-threshold doses, which were evaluated using an optimally sensitized group of animals in the multiple-dose studies, ranged over five orders (0.00006-2.8%). In the LLNA, minimum induction doses ranged over more than three orders (0.01-30%). With respect to 13 biocides that were positive in both the GPMT and the LLNA, results were quantitatively compared. When compared after conversion to corresponding area doses (microg/cm), the minimum doses required to elicit skin reaction in guinea pigs were always lower than that for induction in mice with all biocides. Correlation between minimum induction doses from the GPMT and the LLNA seemed poor (r=0.57), while that between minimum induction doses in the LLNA and elicitation-threshold doses in the GPMT was relatively good (r=0.73). The results suggest the possibility to estimate human elicitation-threshold doses, which are definitely lacking in the process of risk assessment for skin-sensitizers, from the data of the LLNA.

Estimation of Nasal Tip Support Using Computer-Aided Design and 3-Dimensional Printed Models

PubMed Central

Gray, Eric; Maducdoc, Marlon; Manuel, Cyrus; Wong, Brian J. F.

2016-01-01

IMPORTANCE Palpation of the nasal tip is an essential component of the preoperative rhinoplasty examination. Measuring tip support is challenging, and the forces that correspond to ideal tip support are unknown. OBJECTIVE To identify the integrated reaction force and the minimum and ideal mechanical properties associated with nasal tip support. DESIGN, SETTING, AND PARTICIPANTS Three-dimensional (3-D) printed anatomic silicone nasal models were created using a computed tomographic scan and computer-aided design software. From this model, 3-D printing and casting methods were used to create 5 anatomically correct nasal models of varying constitutive Young moduli (0.042, 0.086, 0.098, 0.252, and 0.302 MPa) from silicone. Thirty rhinoplasty surgeons who attended a regional rhinoplasty course evaluated the reaction force (nasal tip recoil) of each model by palpation and selected the model that satisfied their requirements for minimum and ideal tip support. Data were collected from May 3 to 4, 2014. RESULTS Of the 30 respondents, 4 surgeons had been in practice for 1 to 5 years; 9 surgeons, 6 to 15 years; 7 surgeons, 16 to 25 years; and 10 surgeons, 26 or more years. Seventeen surgeons considered themselves in the advanced to expert skill competency levels. Logistic regression estimated the minimum threshold for the Young moduli for adequate and ideal tip support to be 0.096 and 0.154 MPa, respectively. Logistic regression estimated the thresholds for the reaction force associated with the absolute minimum and ideal requirements for good tip recoil to be 0.26 to 4.74 N and 0.37 to 7.19 N during 1- to 8-mm displacement, respectively. CONCLUSIONS AND RELEVANCE This study presents a method to estimate clinically relevant nasal tip reaction forces, which serve as a proxy for nasal tip support. This information will become increasingly important in computational modeling of nasal tip mechanics and ultimately will enhance surgical planning for rhinoplasty. LEVEL OF EVIDENCE NA. PMID:27124818

Assessment of Minimum Important Difference and Substantial Clinical Benefit with the Vascular Quality of Life Questionnaire-6 when Evaluating Revascularisation Procedures in Peripheral Arterial Disease.

PubMed

Nordanstig, J; Pettersson, M; Morgan, M; Falkenberg, M; Kumlien, C

2017-09-01

Patient reported outcomes are increasingly used to assess outcomes after peripheral arterial disease (PAD) interventions. VascuQoL-6 (VQ-6) is a PAD specific health-related quality of life (HRQoL) instrument for routine clinical practice and clinical research. This study assessed the minimum important difference for the VQ-6 and determined thresholds for the minimum important difference and substantial clinical benefit following PAD revascularisation. This was a population-based observational cohort study. VQ-6 data from the Swedvasc Registry (January 2014 to September 2016) was analysed for revascularised PAD patients. The minimum important difference was determined using a combination of a distribution based and an anchor-based method, while receiver operating characteristic curve analysis (ROC) was used to determine optimal thresholds for a substantial clinical benefit following revascularisation. A total of 3194 revascularised PAD patients with complete VQ-6 baseline recordings (intermittent claudication (IC) n = 1622 and critical limb ischaemia (CLI) n = 1572) were studied, of which 2996 had complete VQ-6 recordings 30 days and 1092 a year after the vascular intervention. The minimum important difference 1 year after revascularisation for IC patients ranged from 1.7 to 2.2 scale steps, depending on the method of analysis. Among CLI patients, the minimum important difference after 1 year was 1.9 scale steps. ROC analyses demonstrated that the VQ-6 discriminative properties for a substantial clinical benefit was excellent for IC patients (area under curve (AUC) 0.87, sensitivity 0.81, specificity 0.76) and acceptable in CLI (AUC 0.736, sensitivity 0.63, specificity 0.72). An optimal VQ-6 threshold for a substantial clinical benefit was determined at 3.5 scale steps among IC patients and 4.5 in CLI patients. The suggested thresholds for minimum important difference and substantial clinical benefit could be used when evaluating VQ-6 outcomes following different interventions in PAD and in the design of clinical trials. Copyright © 2017 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Vocal warm-up increases phonation threshold pressure in soprano singers at high pitch.

PubMed

Motel, Tamara; Fisher, Kimberly V; Leydon, Ciara

2003-06-01

Vocal warm-up is thought to optimize singing performance. We compared effects of short-term, submaximal, vocal warm-up exercise with those of vocal rest on the soprano voice (n = 10, ages 19-21 years). Dependent variables were the minimum subglottic air pressure required for vocal fold oscillation to occur (phonation threshold pressure, Pth), and the maximum and minimum phonation fundamental frequency. Warm-up increased Pth for high pitch phonation (p = 0.033), but not for comfortable (p = 0.297) or low (p = 0.087) pitch phonation. No significant difference in the maximum phonation frequency (p = 0.193) or minimum frequency (p = 0.222) was observed. An elevated Pth at controlled high pitch, but an unchanging maximum and minimum frequency production suggests that short-term vocal exercise may increase the viscosity of the vocal fold and thus serve to stabilize the high voice.

The human, primate and rabbit ultraviolet action spectra

NASA Technical Reports Server (NTRS)

Pitts, D. G.; Gibbons, W. D.

1972-01-01

A 5000 watt xenon-mercury high pressure lamp was used to produce a continuous ultraviolet spectrum. Human and animal exposures were made to establish the photokeratitis threshold and abiotic action spectrum. The lower limit of the abiotic action spectrum was 220 nm while the upper limit was 310 nm. The radiant exposure threshold at 270 nm was 0.005 watts/sq cm for the rabbit, 0.004 watts/sq cm for the primate, and 0.004 watts/ sq cm for the human. The rabbit curve was bi-peaked with minimums at 220 nm, 240 nm and 270 nm. The primate curve was tri-peaked with minimums at 220 nm, 240 nm and 270 nm. The human data showed a rather shallow curve with a minimum at 270 nm. Formulas and calculations are given to predict minimum exposure times for ocular damage to man in outer space, to establish valid safety criteria, and to establish protective design criteria.

Extinction-effective population index: incorporating life-history variations in population viability analysis.

PubMed

Fujiwara, Masami

2007-09-01

Viability status of populations is a commonly used measure for decision-making in the management of populations. One of the challenges faced by managers is the need to consistently allocate management effort among populations. This allocation should in part be based on comparison of extinction risks among populations. Unfortunately, common criteria that use minimum viable population size or count-based population viability analysis (PVA) often do not provide results that are comparable among populations, primarily because they lack consistency in determining population size measures and threshold levels of population size (e.g., minimum viable population size and quasi-extinction threshold). Here I introduce a new index called the "extinction-effective population index," which accounts for differential effects of demographic stochasticity among organisms with different life-history strategies and among individuals in different life stages. This index is expected to become a new way of determining minimum viable population size criteria and also complement the count-based PVA. The index accounts for the difference in life-history strategies of organisms, which are modeled using matrix population models. The extinction-effective population index, sensitivity, and elasticity are demonstrated in three species of Pacific salmonids. The interpretation of the index is also provided by comparing them with existing demographic indices. Finally, a measure of life-history-specific effect of demographic stochasticity is derived.

Designing adaptive operating rules for a large multi-purpose reservoir

NASA Astrophysics Data System (ADS)

Geressu, Robel; Rougé, Charles; Harou, Julien

2017-04-01

Reservoirs whose live storage capacity is large compared with annual inflow have "memory", i.e., their storage levels contain information about past inflows and reservoir operations. Such "long-memory" reservoirs can be found in basins in dry regions such as the Nile River Basin in Africa, the Colorado River Basin in the US, or river basins in Western and Central Asia. There the effects of a dry year have the potential to impact reservoir levels and downstream releases for several subsequent years, prompting tensions in transboundary basins. Yet, current reservoir operation rules in those reservoirs do not reflect this by integrating past climate history and release decisions among the factors that influence operating decisions. This work proposes and demonstrates an adaptive reservoir operating rule that explicitly accounts for the recent history of release decisions, and not only current storage level and near-term inflow forecasts. This implies adding long-term (e.g., multiyear) objectives to the existing short-term (e.g., annual) ones. We apply these operating rules to the Grand Ethiopian Renaissance Dam, a large reservoir under construction on the Blue Nile River. Energy generation has to be balanced with the imperative of releasing enough water in low flow years (e.g., the minimum 1, 2 or 3 year cumulative flow) to avoid tensions with downstream countries, Sudan and Egypt. Maximizing the minimum multi-year releases could be of interest for the Nile problem to minimize the impact on performance of the large High Aswan Dam in Egypt. Objectives include maximizing the average and minimum annual energy generation and maximizing the minimum annual, two year and three year cumulative releases. The system model is tested using 30 stochastically generated streamflow series. One can then derive adaptive release rules depending on the value of one- and two-year total releases with respect to thresholds. Then, there are 3 sets of release rules for the reservoir depending on whether one or both thresholds are not met, vs. only one with a non-adaptive rule. Multi-objective evolutionary algorithms (MOEAs) are used to obtain the Pareto front, i.e., non-dominated adaptive and non-adaptive operating rule sets. Implementing adaptive rules is found to improve the trade-offs between energy generation criteria and minimum release targets. Compared with non-adaptive operations, an adaptive operating policy shows an increase of around 3 and 10 Billion cubic meters in the minimum 1 and 3-year cumulative releases for a given value of the same average annual energy generation.

Dying piece by piece: carbohydrate dynamics in aspen (Populus tremuloides) seedlings under severe carbon stress.

PubMed

Wiley, Erin; Hoch, Günter; Landhäusser, Simon M

2017-11-02

Carbon starvation as a mechanism of tree mortality is poorly understood. We exposed seedlings of aspen (Populus tremuloides) to complete darkness at 20 or 28 °C to identify minimum non-structural carbohydrate (NSC) concentrations at which trees die and to see if these levels vary between organs or with environmental conditions. We also first grew seedlings under different shade levels to determine if size affects survival time under darkness due to changes in initial NSC concentration and pool size and/or respiration rates. Darkness treatments caused a gradual dieback of tissues. Even after half the stem had died, substantial starch reserves were still present in the roots (1.3-3% dry weight), indicating limitations to carbohydrate remobilization and/or transport during starvation in the absence of water stress. Survival time decreased with increased temperature and with increasing initial shade level, which was associated with smaller biomass, higher respiration rates, and initially smaller NSC pool size. Dead tissues generally contained no starch, but sugar concentrations were substantially above zero and differed between organs (~2% in stems up to ~7.5% in leaves) and, at times, between temperature treatments and initial, pre-darkness shade treatments. Minimum root NSC concentrations were difficult to determine because dead roots quickly began to decompose, but we identify 5-6% sugar as a potential threshold for living roots. This variability may complicate efforts to identify critical NSC thresholds below which trees starve. © Society for Experimental Biology 2017.

Geometry and starvation effects in hydrodynamic lubrication

NASA Technical Reports Server (NTRS)

Brewe, D.; Hamrock, B. J.

1982-01-01

Numerical methods were used to detemine the effects of lubricant starvation on the minimum film thickness under conditions of a hydrodynamic point contact. Starvation was effected by varying the fluid inlet level. The Reynolds boundary conditions were applied at the cavitation boundary and zero pressure was stipulated at the meniscus or inlet boundary. A minimum film thickness equation as a function of both the ratio of dimensionless load to dimensionless speed and inlet supply level was determined. By comparing the film generated under the starved inlet condition with the film generated from the fully flooded inlet, an expression for the film reduction factor was obtained. Based on this factor a starvation threshold was defined as well as a critically starved inlet. The changes in the inlet pressure buildup due to changing the available lubricant supply are presented in the form of three dimensional isometric plots and also in the form of contour plots.

MSFC Skylab contamination control systems mission evaluation

NASA Technical Reports Server (NTRS)

1974-01-01

Cluster external contamination control evaluation was made throughout the Skylab Mission. This evaluation indicated that contamination control measures instigated during the design, development, and operational phases of this program were adequate to reduce the general contamination environment external to the Cluster below the threshold senstivity levels for experiments and affected subsystems. Launch and orbit contamination control features included eliminating certain vents, rerouting vents for minimum contamination impact, establishing filters, incorporating materials with minimum outgassing characteristics and developing operational constraints and mission rules to minimize contamination effects. Prior to the launch of Skylab, contamination control math models were developed which were used to predict Cluster surface deposition and background brightness levels throughout the mission. The report summarizes the Skylab system and experiment contamination control evaluation. The Cluster systems and experiments evaluated include Induced Atmosphere, Corollary and ATM Experiments, Thermal Control Surfaces, Solar Array Systems, Windows and Star Tracker.

Analysis of starvation effects on hydrodynamic lubrication in nonconforming contacts

NASA Technical Reports Server (NTRS)

Brewe, D. E.; Hamrock, B. J.

1981-01-01

Numerical methods were used to determine the effects of lubricant starvation on the minimum film thickness under conditions of a hydrodynamic point contact. Starvation was effected by varying the fluid inlet level. The Reynolds boundary conditions were applied at the cavitation boundary and zero pressure was stipulated at the meniscus or inlet boundary. A minimum-fill-thickness equation as a function of both the ratio of dimensionless load to dimensionless speed and inlet supply level was determined. By comparing the film generated under the starved inlet condition with the film generated from the fully flooded inlet, an expression for the film reduction factor was obtained. Based on this factor a starvation threshold was defined as well as a critically starved inlet. The changes in the inlet pressure buildup due to changing the available lubricant supply are presented in the form of three dimensional isometric plots and also in the form of contour plots.

Geometry and starvation effects in hydrodynamic lubrication

NASA Technical Reports Server (NTRS)

Brewe, D. E.; Hamrock, B. J.

1982-01-01

Numerical methods were used to determine the effects of lubricant starvation on the minimum film thickness under conditions of a hydrodynamic point contact. Starvation was effected by varying the fluid inlet level. The Reynolds boundary conditions were applied at the cavitation boundary and zero pressure was stipulated at the meniscus or inlet boundary. A minimum-film-thickness equation as a function of both the ratio of dimensionless load to dimensionless speed and inlet supply level was determined. By comparing the film generated under the starved inlet condition with the film generated from the fully flooded inlet, an expression for the film reduction factor was obtained. Based on this factor a starvation threshold was defined as well as a critically starved inlet. The changes in the inlet pressure buildup due to changing the available lubricant supply are presented in the form of three dimensional isometric plots and also in the form of contour plots.

Rate-Compatible Protograph LDPC Codes

NASA Technical Reports Server (NTRS)

Nguyen, Thuy V. (Inventor); Nosratinia, Aria (Inventor); Divsalar, Dariush (Inventor)

2014-01-01

Digital communication coding methods resulting in rate-compatible low density parity-check (LDPC) codes built from protographs. Described digital coding methods start with a desired code rate and a selection of the numbers of variable nodes and check nodes to be used in the protograph. Constraints are set to satisfy a linear minimum distance growth property for the protograph. All possible edges in the graph are searched for the minimum iterative decoding threshold and the protograph with the lowest iterative decoding threshold is selected. Protographs designed in this manner are used in decode and forward relay channels.

Using threshold messages to promote physical activity: implications for public perceptions of health effects.

PubMed

Knox, Emily C L; Webb, Oliver J; Esliger, Dale W; Biddle, Stuart J H; Sherar, Lauren B

2014-04-01

The promotion of physical activity (PA) guidelines to the general public is an important issue that lacks empirical investigation. PA campaigns often feature participation thresholds that cite PA guidelines verbatim [e.g., 150 min/week moderate-to-vigorous physical activity (MVPA)]. Some campaigns instead prefer to use generic PA messages (e.g., do as much MVPA as possible). 'Thresholds' may disrupt understanding of the health benefits of modest PA participation. This study examined the perception of health benefits of PA after exposure to PA messages that did and did not contain a duration threshold. Brief structured interviews were conducted with a convenience sample of adults (n = 1100). Participants received a threshold message (150 min/week MVPA), a message that presented the threshold as a minimum; a generic message or no message. Participants rated perceived health effects of seven PA durations. One-way analyses of variance with post hoc tests for group differences were used to assess raw perception ratings for each duration of PA. Recipients of all three messages held more positive perceptions of >150 min/week of MVPA relative to those not receiving any message. For MVPA durations <150 min/week, the generic PA message group perceived the greatest health benefits. Those receiving the threshold message tended to have the least positive perceptions of durations <150 min/week. Threshold messages were associated with lower perceived health benefits for modest PA durations. Campaigns based on threshold messages may be limited when promoting small PA increases at a population level.

Geospatial Association between Low Birth Weight and Arsenic in Groundwater in New Hampshire, USA

PubMed Central

Shi, Xun; Ayotte, Joseph D.; Onda, Akikazu; Miller, Stephanie; Rees, Judy; Gilbert-Diamond, Diane; Onega, Tracy; Gui, Jiang; Karagas, Margaret; Moeschler, John

2015-01-01

Background There is increasing evidence of the role of arsenic in the etiology of adverse human reproductive outcomes. Since drinking water can be a major source of arsenic to pregnant women, the effect of arsenic exposure through drinking water on human birth may be revealed by a geospatial association between arsenic concentration in groundwater and birth problems, particularly in a region where private wells substantially account for water supply, like New Hampshire, US. Methods We calculated town-level rates of preterm birth and term low birth weight (term LBW) for New Hampshire, using data for 1997-2009 and stratified by maternal age. We smoothed the rates using a locally-weighted averaging method to increase the statistical stability. The town-level groundwater arsenic values are from three GIS data layers generated by the US Geological Survey: probability of local groundwater arsenic concentration > 1 μg/L, probability > 5 μg/L, and probability > 10 μg/L. We calculated Pearson's correlation coefficients (r) between the reproductive outcomes (preterm birth and term LBW) and the arsenic values, at both state and county levels. Results For preterm birth, younger mothers (maternal age < 20) have a statewide r = 0.70 between the rates smoothed with a threshold = 2,000 births and the town mean arsenic level based on the data of probability > 10 μg/L; For older mothers, r = 0.19 when the smoothing threshold = 3,500; A majority of county level r values are positive based on the arsenic data of probability > 10 μg/L. For term LBW, younger mothers (maternal age < 25) have a statewide r = 0.44 between the rates smoothed with a threshold = 3,500 and town minimum arsenic level based on the data of probability > 1 μg/L; For older mothers, r = 0.14 when the rates are smoothed with a threshold = 1,000 births and also adjusted by town median household income in 1999, and the arsenic values are the town minimum based on probability > 10 μg/L. At the county level, for younger mothers positive r values prevail, but for older mothers it is a mix. For both birth problems, the several most populous counties - with 60-80% of the state's population and clustering at the southwest corner of the state – are largely consistent in having a positive r across different smoothing thresholds. Conclusion We found evident spatial associations between the two adverse human reproductive outcomes and groundwater arsenic in New Hampshire, US. However, the degree of associations and their sensitivity to different representations of arsenic level are variable. Generally, preterm birth has a stronger spatial association with groundwater arsenic than term LBW, suggesting an inconsistency in the impact of arsenic on the two reproductive outcomes. For both outcomes, younger maternal age has stronger spatial associations with groundwater arsenic. PMID:25326895

Assessment of PCBs and exposure risk to infants in breast milk of primiparae and multiparae mothers in an electronic waste hot spot and non-hot spot areas in Ghana.

PubMed

Asamoah, Anita; Essumang, David Kofi; Muff, Jens; Kucheryavskiy, Sergey V; Søgaard, Erik Gydesen

2018-01-15

The aim of the study was to assess the levels of PCBs in the breast milk of some Ghanaian women at suspected hotspot and relatively non-hotspot areas and to find out if the levels of these PCBs pose any risk to the breastfed infants. A total of 128 individual human breast milk were sampled from both primiparae and multiparae mothers. The levels of PCBs in the milk samples were compared. Some of these mothers (105 individuals) work or reside in and around Agbogbloshie (hot-spot), the largest electric and electronic waste dump and recycling site in Accra, Ghana. Others (23 donor mothers) also reside in and around Kwabenya (non-hotspot) which is a mainly residential area without any industrial activities. Samples were analyzed using GC-MS/MS. The total mean levels and range of Σ 7 PCBs were 3.64ng/glipidwt and ˂LOD-29.20ng/glipidwt, respectively. Mean concentrations from Agbogbloshie (hot-spot area) and Kwabenya (non-hotspot areas) were 4.43ng/glipidwt and 0.03ng/glipidwt, respectively. PCB-28 contributed the highest of 29.5% of the total PCBs in the milk samples, and PCB-101 contributed the lowest of 1.74%. The estimated daily intake of PCBs and total PCBs concentrations in this work were found to be lower as compared to similar studies across the world. The estimated hazard quotient using Health Canada's guidelines threshold limit of 1μg/kgbw/day showed no potential health risk to babies. However, considering minimum tolerable value of 0.03μg/kgbw/day defined by the Agency for Toxic Substances and Disease Registry (ATSDR), the values of some mothers were found to be at the threshold limit. This may indicate a potential health risk to their babies. Mothers with values at the threshold levels of the minimum tolerable limits are those who work or reside in and around the Agbogbloshie e-waste site. Copyright © 2017 Elsevier B.V. All rights reserved.

An Analysis Of The Benefits And Application Of Earned Value Management (EVM) Project Management Techniques For Dod Programs That Do Not Meet Dod Policy Thresholds

DTIC Science & Technology

2017-12-01

carefully to ensure only minimum information needed for effective management control is requested.  Requires cost-benefit analysis and PM...baseline offers metrics that highlights performance treads and program variances. This information provides Program Managers and higher levels of...The existing training philosophy is effective only if the managers using the information have well trained and experienced personnel that can

Two-IMU FDI performance of the sequential probability ratio test during shuttle entry

NASA Technical Reports Server (NTRS)

Rich, T. M.

1976-01-01

Performance data for the sequential probability ratio test (SPRT) during shuttle entry are presented. Current modeling constants and failure thresholds are included for the full mission 3B from entry through landing trajectory. Minimum 100 percent detection/isolation failure levels and a discussion of the effects of failure direction are presented. Finally, a limited comparison of failures introduced at trajectory initiation shows that the SPRT algorithm performs slightly worse than the data tracking test.

Regulating the medical loss ratio: implications for the individual market.

PubMed

Abraham, Jean M; Karaca-Mandic, Pinar

2011-03-01

To provide state-level estimates of the size and structure of the US individual market for health insurance and to investigate the potential impact of new medical loss ratio (MLR) regulation in 2011, as indicated by the Patient Protection and Affordable Care Act (PPACA). Using data from the National Association of Insurance Commissioners, we provided state-level estimates of the size and structure of the US individual market from 2002 to 2009. We estimated the number of insurers expected to have MLRs below the legislated minimum and their corresponding enrollment. In the case of noncompliant insurers exiting the market, we estimated the number of enrollees that may be vulnerable to major coverage disruption given poor health status. In 2009, using a PPACA-adjusted MLR definition, we estimated that 29% of insurer-state observations in the individual market would have MLRs below the 80% minimum, corresponding to 32% of total enrollment. Nine states would have at least one-half of their health insurers below the threshold. If insurers below the MLR threshold exit the market, major coverage disruption could occur for those in poor health; we estimated the range to be between 104,624 and 158,736 member-years. The introduction of MLR regulation as part of the PPACA has the potential to significantly affect the functioning of the individual market for health insurance.

Porcine skin damage thresholds for pulsed nanosecond-scale laser exposure at 1064-nm

NASA Astrophysics Data System (ADS)

DeLisi, Michael P.; Peterson, Amanda M.; Noojin, Gary D.; Shingledecker, Aurora D.; Tijerina, Amanda J.; Boretsky, Adam R.; Schmidt, Morgan S.; Kumru, Semih S.; Thomas, Robert J.

2018-02-01

Pulsed high-energy lasers operating in the near-infrared (NIR) band are increasingly being used in medical, industrial, and military applications, but there are little available experimental data to characterize their hazardous effects on skin tissue. The current American National Standard for the Safe Use of Lasers (ANSI Z136.1-2014) defines the maximum permissible exposure (MPE) on the skin as either a single-pulse or total exposure time limit. This study determined the minimum visible lesion (MVL) damage thresholds in Yucatan miniature pig skin for the single-pulse case and several multiple-pulse cases over a wide range of pulse repetition frequencies (PRFs) (10, 125, 2,000, and 10,000 Hz) utilizing nanosecond-scale pulses (10 or 60 ns). The thresholds are expressed in terms of the median effective dose (ED50) based on varying individual pulse energy with other laser parameters held constant. The results confirm a decrease in MVL threshold as PRF increases for exposures with a constant number of pulses, while also noting a PRF-dependent change in the threshold as a function of the number of pulses. Furthermore, this study highlights a change in damage mechanism to the skin from melanin-mediated photomechanical events at high irradiance levels and few numbers of pulses to bulk tissue photothermal additivity at lower irradiance levels and greater numbers of pulses. The observed trends exceeded the existing exposure limits by an average factor of 9.1 in the photothermally-damaged cases and 3.6 in the photomechanicallydamaged cases.

In the right place at the right time: habitat representation in protected areas of South American Nothofagus-dominated plants after a dispersal constrained climate change scenario.

PubMed

Alarcón, Diego; Cavieres, Lohengrin A

2015-01-01

In order to assess the effects of climate change in temperate rainforest plants in southern South America in terms of habitat size, representation in protected areas, considering also if the expected impacts are similar for dominant trees and understory plant species, we used niche modeling constrained by species migration on 118 plant species, considering two groups of dominant trees and two groups of understory ferns. Representation in protected areas included Chilean national protected areas, private protected areas, and priority areas planned for future reserves, with two thresholds for minimum representation at the country level: 10% and 17%. With a 10% representation threshold, national protected areas currently represent only 50% of the assessed species. Private reserves are important since they increase up to 66% the species representation level. Besides, 97% of the evaluated species may achieve the minimum representation target only if the proposed priority areas were included. With the climate change scenario representation levels slightly increase to 53%, 69%, and 99%, respectively, to the categories previously mentioned. Thus, the current location of all the representation categories is useful for overcoming climate change by 2050. Climate change impacts on habitat size and representation of dominant trees in protected areas are not applicable to understory plants, highlighting the importance of assessing these effects with a larger number of species. Although climate change will modify the habitat size of plant species in South American temperate rainforests, it will have no significant impact in terms of the number of species adequately represented in Chile, where the implementation of the proposed reserves is vital to accomplish the present and future minimum representation. Our results also show the importance of using migration dispersal constraints to develop more realistic future habitat maps from climate change predictions.

In the Right Place at the Right Time: Habitat Representation in Protected Areas of South American Nothofagus-Dominated Plants after a Dispersal Constrained Climate Change Scenario

PubMed Central

Alarcón, Diego; Cavieres, Lohengrin A.

2015-01-01

In order to assess the effects of climate change in temperate rainforest plants in southern South America in terms of habitat size, representation in protected areas, considering also if the expected impacts are similar for dominant trees and understory plant species, we used niche modeling constrained by species migration on 118 plant species, considering two groups of dominant trees and two groups of understory ferns. Representation in protected areas included Chilean national protected areas, private protected areas, and priority areas planned for future reserves, with two thresholds for minimum representation at the country level: 10% and 17%. With a 10% representation threshold, national protected areas currently represent only 50% of the assessed species. Private reserves are important since they increase up to 66% the species representation level. Besides, 97% of the evaluated species may achieve the minimum representation target only if the proposed priority areas were included. With the climate change scenario representation levels slightly increase to 53%, 69%, and 99%, respectively, to the categories previously mentioned. Thus, the current location of all the representation categories is useful for overcoming climate change by 2050. Climate change impacts on habitat size and representation of dominant trees in protected areas are not applicable to understory plants, highlighting the importance of assessing these effects with a larger number of species. Although climate change will modify the habitat size of plant species in South American temperate rainforests, it will have no significant impact in terms of the number of species adequately represented in Chile, where the implementation of the proposed reserves is vital to accomplish the present and future minimum representation. Our results also show the importance of using migration dispersal constraints to develop more realistic future habitat maps from climate change predictions. PMID:25786226

Geospatial association between adverse birth outcomes and arsenic in groundwater in New Hampshire, USA.

PubMed

Shi, Xun; Ayotte, Joseph D; Onda, Akikazu; Miller, Stephanie; Rees, Judy; Gilbert-Diamond, Diane; Onega, Tracy; Gui, Jiang; Karagas, Margaret; Moeschler, John

2015-04-01

There is increasing evidence of the role of arsenic in the etiology of adverse human reproductive outcomes. Because drinking water can be a major source of arsenic to pregnant women, the effect of arsenic exposure through drinking water on human birth may be revealed by a geospatial association between arsenic concentration in groundwater and birth problems, particularly in a region where private wells substantially account for water supply, like New Hampshire, USA. We calculated town-level rates of preterm birth and term low birth weight (term LBW) for New Hampshire, by using data for 1997-2009 stratified by maternal age. We smoothed the rates by using a locally weighted averaging method to increase the statistical stability. The town-level groundwater arsenic probability values are from three GIS data layers generated by the US Geological Survey: probability of local groundwater arsenic concentration >1 µg/L, probability >5 µg/L, and probability >10 µg/L. We calculated Pearson's correlation coefficients (r) between the reproductive outcomes (preterm birth and term LBW) and the arsenic probability values, at both state and county levels. For preterm birth, younger mothers (maternal age <20) have a statewide r = 0.70 between the rates smoothed with a threshold = 2,000 births and the town mean arsenic level based on the data of probability >10 µg/L; for older mothers, r = 0.19 when the smoothing threshold = 3,500; a majority of county level r values are positive based on the arsenic data of probability >10 µg/L. For term LBW, younger mothers (maternal age <25) have a statewide r = 0.44 between the rates smoothed with a threshold = 3,500 and town minimum arsenic concentration based on the data of probability >1 µg/L; for older mothers, r = 0.14 when the rates are smoothed with a threshold = 1,000 births and also adjusted by town median household income in 1999, and the arsenic values are the town minimum based on probability >10 µg/L. At the county level for younger mothers, positive r values prevail, but for older mothers, it is a mix. For both birth problems, the several most populous counties-with 60-80 % of the state's population and clustering at the southwest corner of the state-are largely consistent in having a positive r across different smoothing thresholds. We found evident spatial associations between the two adverse human reproductive outcomes and groundwater arsenic in New Hampshire, USA. However, the degree of associations and their sensitivity to different representations of arsenic level are variable. Generally, preterm birth has a stronger spatial association with groundwater arsenic than term LBW, suggesting an inconsistency in the impact of arsenic on the two reproductive outcomes. For both outcomes, younger maternal age has stronger spatial associations with groundwater arsenic.

A visual detection model for DCT coefficient quantization

NASA Technical Reports Server (NTRS)

Ahumada, Albert J., Jr.; Watson, Andrew B.

1994-01-01

The discrete cosine transform (DCT) is widely used in image compression and is part of the JPEG and MPEG compression standards. The degree of compression and the amount of distortion in the decompressed image are controlled by the quantization of the transform coefficients. The standards do not specify how the DCT coefficients should be quantized. One approach is to set the quantization level for each coefficient so that the quantization error is near the threshold of visibility. Results from previous work are combined to form the current best detection model for DCT coefficient quantization noise. This model predicts sensitivity as a function of display parameters, enabling quantization matrices to be designed for display situations varying in luminance, veiling light, and spatial frequency related conditions (pixel size, viewing distance, and aspect ratio). It also allows arbitrary color space directions for the representation of color. A model-based method of optimizing the quantization matrix for an individual image was developed. The model described above provides visual thresholds for each DCT frequency. These thresholds are adjusted within each block for visual light adaptation and contrast masking. For given quantization matrix, the DCT quantization errors are scaled by the adjusted thresholds to yield perceptual errors. These errors are pooled nonlinearly over the image to yield total perceptual error. With this model one may estimate the quantization matrix for a particular image that yields minimum bit rate for a given total perceptual error, or minimum perceptual error for a given bit rate. Custom matrices for a number of images show clear improvement over image-independent matrices. Custom matrices are compatible with the JPEG standard, which requires transmission of the quantization matrix.

Absolute auditory threshold: testing the absolute.

PubMed

Heil, Peter; Matysiak, Artur

2017-11-02

The mechanisms underlying the detection of sounds in quiet, one of the simplest tasks for auditory systems, are debated. Several models proposed to explain the threshold for sounds in quiet and its dependence on sound parameters include a minimum sound intensity ('hard threshold'), below which sound has no effect on the ear. Also, many models are based on the assumption that threshold is mediated by integration of a neural response proportional to sound intensity. Here, we test these ideas. Using an adaptive forced choice procedure, we obtained thresholds of 95 normal-hearing human ears for 18 tones (3.125 kHz carrier) in quiet, each with a different temporal amplitude envelope. Grand-mean thresholds and standard deviations were well described by a probabilistic model according to which sensory events are generated by a Poisson point process with a low rate in the absence, and higher, time-varying rates in the presence, of stimulation. The subject actively evaluates the process and bases the decision on the number of events observed. The sound-driven rate of events is proportional to the temporal amplitude envelope of the bandpass-filtered sound raised to an exponent. We find no evidence for a hard threshold: When the model is extended to include such a threshold, the fit does not improve. Furthermore, we find an exponent of 3, consistent with our previous studies and further challenging models that are based on the assumption of the integration of a neural response that, at threshold sound levels, is directly proportional to sound amplitude or intensity. © 2017 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

A generalized methodology for identification of threshold for HRU delineation in SWAT model

NASA Astrophysics Data System (ADS)

M, J.; Sudheer, K.; Chaubey, I.; Raj, C.

2016-12-01

The distributed hydrological model, Soil and Water Assessment Tool (SWAT) is a comprehensive hydrologic model widely used for making various decisions. The simulation accuracy of the distributed hydrological model differs due to the mechanism involved in the subdivision of the watershed. Soil and Water Assessment Tool (SWAT) considers sub-dividing the watershed and the sub-basins into small computing units known as 'hydrologic response units (HRU). The delineation of HRU is done based on unique combinations of land use, soil types, and slope within the sub-watersheds, which are not spatially defined. The computations in SWAT are done at HRU level and are then aggregated up to the sub-basin outlet, which is routed through the stream system. Generally, the HRUs are delineated by considering a threshold percentage of land use, soil and slope are to be given by the modeler to decrease the computation time of the model. The thresholds constrain the minimum area for constructing an HRU. In the current HRU delineation practice in SWAT, the land use, soil and slope of the watershed within a sub-basin, which is less than the predefined threshold, will be surpassed by the dominating land use, soil and slope, and introduce some level of ambiguity in the process simulations in terms of inappropriate representation of the area. But the loss of information due to variation in the threshold values depends highly on the purpose of the study. Therefore this research studies the effects of threshold values of HRU delineation on the hydrological modeling of SWAT on sediment simulations and suggests guidelines for selecting the appropriate threshold values considering the sediment simulation accuracy. The preliminary study was done on Illinois watershed by assigning different thresholds for land use and soil. A general methodology was proposed for identifying an appropriate threshold for HRU delineation in SWAT model that considered computational time and accuracy of the simulation. The methodology can be adopted for identifying an appropriate threshold for SWAT model simulation in any watershed with a single simulation of the model with a zero-zero threshold.

A Rational Approach to Determine Minimum Strength Thresholds in Novel Structural Materials

NASA Technical Reports Server (NTRS)

Schur, Willi W.; Bilen, Canan; Sterling, Jerry

2003-01-01

Design of safe and survivable structures requires the availability of guaranteed minimum strength thresholds for structural materials to enable a meaningful comparison of strength requirement and available strength. This paper develops a procedure for determining such a threshold with a desired degree of confidence, for structural materials with none or minimal industrial experience. The problem arose in attempting to use a new, highly weight-efficient structural load tendon material to achieve a lightweight super-pressure balloon. The developed procedure applies to lineal (one dimensional) structural elements. One important aspect of the formulation is that it extrapolates to expected probability distributions for long length specimen samples from some hypothesized probability distribution that has been obtained from a shorter length specimen sample. The use of the developed procedure is illustrated using both real and simulated data.

Preceding weak noise sharpens the frequency tuning and elevates the response threshold of the mouse inferior collicular neurons through GABAergic inhibition.

PubMed

Wang, Xin; Jen, Philip H-S; Wu, Fei-Jian; Chen, Qi-Cai

2007-09-05

In acoustic communication, animals must extract biologically relevant signals that are embedded in noisy environment. The present study examines how weak noise may affect the auditory sensitivity of neurons in the central nucleus of the mouse inferior colliculus (IC) which receives convergent excitatory and inhibitory inputs from both lower and higher auditory centers. Specifically, we studied the frequency sensitivity and minimum threshold of IC neurons using a pure tone probe and a weak white noise masker under forward masking paradigm. For most IC neurons, probe-elicited response was decreased by a weak white noise that was presented at a specific gap (i.e. time window). When presented within this time window, weak noise masking sharpened the frequency tuning curve and increased the minimum threshold of IC neurons. The degree of weak noise masking of these two measurements increased with noise duration. Sharpening of the frequency tuning curve and increasing of the minimum threshold of IC neurons during weak noise masking were mostly mediated through GABAergic inhibition. In addition, sharpening of frequency tuning curve by the weak noise masker was more effective at the high than at low frequency limb. These data indicate that in the real world the ambient noise may improve frequency sensitivity of IC neurons through GABAergic inhibition while inevitably decrease the frequency response range and sensitivity of IC neurons.

Minimum Performance on Clinical Tests of Physical Function to Predict Walking 6,000 Steps/Day in Knee Osteoarthritis: An Observational Study.

PubMed

Master, Hiral; Thoma, Louise M; Christiansen, Meredith B; Polakowski, Emily; Schmitt, Laura A; White, Daniel K

2018-07-01

Evidence of physical function difficulties, such as difficulty rising from a chair, may limit daily walking for people with knee osteoarthritis (OA). The purpose of this study was to identify minimum performance thresholds on clinical tests of physical function predictive to walking ≥6,000 steps/day. This benchmark is known to discriminate people with knee OA who develop functional limitation over time from those who do not. Using data from the Osteoarthritis Initiative, we quantified daily walking as average steps/day from an accelerometer (Actigraph GT1M) worn for ≥10 hours/day over 1 week. Physical function was quantified using 3 performance-based clinical tests: 5 times sit-to-stand test, walking speed (tested over 20 meters), and 400-meter walk test. To identify minimum performance thresholds for daily walking, we calculated physical function values corresponding to high specificity (80-95%) to predict walking ≥6,000 steps/day. Among 1,925 participants (mean ± SD age 65.1 ± 9.1 years, mean ± SD body mass index 28.4 ± 4.8 kg/m 2 , and 55% female) with valid accelerometer data, 54.9% walked ≥6,000 steps/day. High specificity thresholds of physical function for walking ≥6,000 steps/day ranged 11.4-14.0 seconds on the 5 times sit-to-stand test, 1.13-1.26 meters/second for walking speed, or 315-349 seconds on the 400-meter walk test. Not meeting these minimum performance thresholds on clinical tests of physical function may indicate inadequate physical ability to walk ≥6,000 steps/day for people with knee OA. Rehabilitation may be indicated to address underlying impairments limiting physical function. © 2017, American College of Rheumatology.

42 CFR 422.208 - Physician incentive plans: requirements and limitations.

Code of Federal Regulations, 2013 CFR

2013-10-01

... difference between the maximum potential payments and the minimum potential payments is more than 25 percent... have the effect of reducing or limiting the services provided to any plan enrollee. Potential payments... considered in this determination. (2) Risk threshold. The risk threshold is 25 percent of potential payments...

42 CFR 422.208 - Physician incentive plans: requirements and limitations.

Code of Federal Regulations, 2014 CFR

2014-10-01

... difference between the maximum potential payments and the minimum potential payments is more than 25 percent... have the effect of reducing or limiting the services provided to any plan enrollee. Potential payments... considered in this determination. (2) Risk threshold. The risk threshold is 25 percent of potential payments...

42 CFR 422.208 - Physician incentive plans: requirements and limitations.

Code of Federal Regulations, 2012 CFR

2012-10-01

... difference between the maximum potential payments and the minimum potential payments is more than 25 percent... have the effect of reducing or limiting the services provided to any plan enrollee. Potential payments... considered in this determination. (2) Risk threshold. The risk threshold is 25 percent of potential payments...

Size-Constrained Region Merging: A New Tool to Derive Basic Landcover Units from Remote Sensing Imagery

NASA Astrophysics Data System (ADS)

Castilla, G.

2004-09-01

Landcover maps typically represent the territory as a mosaic of contiguous units "polygons- that are assumed to correspond to geographic entities" like e.g. lakes, forests or villages-. They may also be viewed as representing a particular level of a landscape hierarchy where each polygon is a holon - an object made of subobjects and part of a superobject. The focal level portrayed in the map is distinguished from other levels by the average size of objects compounding it. Moreover, the focal level is bounded by the minimum size that objects of this level are supposed to have. Based on this framework, we have developed a segmentation method that defines a partition on a multiband image such that i) the mean size of segments is close to the one specified; ii) each segment exceeds the required minimum size; and iii) the internal homogeneity of segments is maximal given the size constraints. This paper briefly describes the method, focusing on its region merging stage. The most distinctive feature of the latter is that while the merging sequence is ordered by increasing dissimilarity as in conventional methods, there is no need to define a threshold on the dissimilarity measure between adjacent segments.

75 FR 66188 - Sentencing Guidelines for United States Courts

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-27

...) by striking ``five kilograms of marihuana'' and inserting ``2 grams of cocaine base''; by inserting... required to trigger the 5-year mandatory minimum term of imprisonment was increased from 5 grams to 28 grams, and the quantity threshold required to trigger the 10-year mandatory minimum term of imprisonment...

Re-examination of immune response and estimation of anti-Vi IgG protective threshold against typhoid fever-based on the efficacy trial of Vi conjugate in young children.

PubMed

Szu, Shousun C; Klugman, Keith P; Hunt, Steven

2014-04-25

The capsular polysaccharide of Salmonella enterica serovar Typhi, Vi antigen, is an essential virulence factor and a protective antigen. Similar to other polysaccharide vaccines, the protective action of Vi, both to the polysaccharide alone or when presented as a conjugate, is mediated by serum IgG Vi antibodies. The evaluation of Vi capsular polysaccharide based vaccines to prevent typhoid fever would be significantly facilitated by the identification of a "protective level" of serum antibodies to Vi antigen. The protective level of anti-Vi IgG against typhoid fever was derived from the protective efficacy and immune response of a Vi-rEPA conjugate vaccine efficacy trial. The estimation was derived by two methods: correlation of the percent efficacy and the antibody distribution profile in the vaccine group at a given period of observation, and use of the relative ratio of anti-Vi IgG levels between the vaccine and placebo groups greater or equal to the Relative Risk of typhoid fever used in the efficacy determination. Both methods predicted a similar range of a minimum protective level of anti-Vi IgG between 1.4 and 2.0μg/ml (short term threshold). When applying a protective threshold of 10μg/ml at 6 months post immunization, an IgG level in excess of 1.4μg/ml was achieved by 90% of children at 46 months post immunization, consistent with an 89% level of protection over the duration of the study. We thus suggest that the proportion of children with Vi IgG>10μg/ml (long term threshold) 6 months after immunization may reflect the proportion protected over at least a 4 year period. The current assignment of an anti-Vi IgG protective level may be of value when evaluating vaccine performance of future Vi conjugate vaccines. Published by Elsevier Ltd.

Threshold Assessment of Gear Diagnostic Tools on Flight and Test Rig Data

NASA Technical Reports Server (NTRS)

Dempsey, Paula J.; Mosher, Marianne; Huff, Edward M.

2003-01-01

A method for defining thresholds for vibration-based algorithms that provides the minimum number of false alarms while maintaining sensitivity to gear damage was developed. This analysis focused on two vibration based gear damage detection algorithms, FM4 and MSA. This method was developed using vibration data collected during surface fatigue tests performed in a spur gearbox rig. The thresholds were defined based on damage progression during tests with damage. The thresholds false alarm rates were then evaluated on spur gear tests without damage. Next, the same thresholds were applied to flight data from an OH-58 helicopter transmission. Results showed that thresholds defined in test rigs can be used to define thresholds in flight to correctly classify the transmission operation as normal.

Optical ranked-order filtering using threshold decomposition

DOEpatents

Allebach, Jan P.; Ochoa, Ellen; Sweeney, Donald W.

1990-01-01

A hybrid optical/electronic system performs median filtering and related ranked-order operations using threshold decomposition to encode the image. Threshold decomposition transforms the nonlinear neighborhood ranking operation into a linear space-invariant filtering step followed by a point-to-point threshold comparison step. Spatial multiplexing allows parallel processing of all the threshold components as well as recombination by a second linear, space-invariant filtering step. An incoherent optical correlation system performs the linear filtering, using a magneto-optic spatial light modulator as the input device and a computer-generated hologram in the filter plane. Thresholding is done electronically. By adjusting the value of the threshold, the same architecture is used to perform median, minimum, and maximum filtering of images. A totally optical system is also disclosed.

Measurement of the lowest dosage of phenobarbital that can produce drug discrimination in rats

PubMed Central

Overton, Donald A.; Stanwood, Gregg D.; Patel, Bhavesh N.; Pragada, Sreenivasa R.; Gordon, M. Kathleen

2009-01-01

Rationale Accurate measurement of the threshold dosage of phenobarbital that can produce drug discrimination (DD) may improve our understanding of the mechanisms and properties of such discrimination. Objectives Compare three methods for determining the threshold dosage for phenobarbital (D) versus no drug (N) DD. Methods Rats learned a D versus N DD in 2-lever operant training chambers. A titration scheme was employed to increase or decrease dosage at the end of each 18-day block of sessions depending on whether the rat had achieved criterion accuracy during the sessions just completed. Three criterion rules were employed, all based on average percent drug lever responses during initial links of the last 6 D and 6 N sessions of a block. The criteria were: D%>66 and N%<33; D%>50 and N%<50; (D%-N%)>33. Two squads of rats were trained, one immediately after the other. Results All rats discriminated drug versus no drug. In most rats, dosage decreased to low levels and then oscillated near the minimum level required to maintain criterion performance. The lowest discriminated dosage significantly differed under the three criterion rules. The squad that was trained 2nd may have benefited by partially duplicating the lever choices of the previous squad. Conclusions The lowest discriminated dosage is influenced by the criterion of discriminative control that is employed, and is higher than the absolute threshold at which discrimination entirely disappears. Threshold estimations closer to absolute threshold can be obtained when criteria are employed that are permissive, and that allow rats to maintain lever preferences. PMID:19082992

The perception of complex tones by a false killer whale (Pseudorca crassidens).

PubMed

Yuen, Michelle M L; Nachtigall, Paul E; Breese, Marlee; Vlachos, Stephanie A

2007-03-01

Complex tonal whistles are frequently produced by some odontocete species. However, no experimental evidence exists regarding the detection of complex tones or the discrimination of harmonic frequencies by a marine mammal. The objectives of this investigation were to examine the ability of a false killer whale to discriminate pure tones from complex tones and to determine the minimum intensity level of a harmonic tone required for the whale to make the discrimination. The study was conducted with a go/no-go modified staircase procedure. The different stimuli were complex tones with a fundamental frequency of 5 kHz with one to five harmonic frequencies. The results from this complex tone discrimination task demonstrated: (1) that the false killer whale was able to discriminate a 5 kHz pure tone from a complex tone with up to five harmonics, and (2) that discrimination thresholds or minimum intensity levels exist for each harmonic combination measured. These results indicate that both frequency level and harmonic content may have contributed to the false killer whale's discrimination of complex tones.

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... methods: Electronic Submission: Submit all electronic public comments via the Federal e-Rulemaking Portal http://www.regulations.gov . To submit comments via the e-Rulemaking Portal, first click the ``submit a...-frame. The overfished threshold would also be revised. The overfished threshold or minimum stock size...

Ab initio molecular dynamics simulations of low energy recoil events in MgO

NASA Astrophysics Data System (ADS)

Petersen, B. A.; Liu, B.; Weber, W. J.; Zhang, Y.

2017-04-01

Low-energy recoil events in MgO are studied using ab intio molecular dynamics simulations to reveal the dynamic displacement processes and final defect configurations. Threshold displacement energies, Ed, are obtained for Mg and O along three low-index crystallographic directions, [100], [110], and [111]. The minimum values for Ed are found along the [110] direction consisting of the same element, either Mg or O atoms. Minimum threshold values of 29.5 eV for Mg and 25.5 eV for O, respectively, are suggested from the calculations. For other directions, the threshold energies are considerably higher, 65.5 and 150.0 eV for O along [111] and [100], and 122.5 eV for Mg along both [111] and [100] directions, respectively. These results show that the recoil events in MgO are partial-charge transfer assisted processes where the charge transfer plays an important role. There is a similar trend found in other oxide materials, where the threshold displacement energy correlates linearly with the peak partial-charge transfer, suggesting this behavior might be universal in ceramic oxides.

Infants born very preterm react to variations of the acoustic environment in their incubator from a minimum signal-to-noise ratio threshold of 5 to 10 dBA.

PubMed

Kuhn, Pierre; Zores, Claire; Pebayle, Thierry; Hoeft, Alain; Langlet, Claire; Escande, Benoît; Astruc, Dominique; Dufour, André

2012-04-01

Very early preterm infants (VPIs) are exposed to unpredictable noise in neonatal intensive care units. Their ability to perceive moderate acoustic environmental changes has not been fully investigated. Physiological values of the 598 isolated sound peaks (SPs) that were 5-10 and 10-15 dB slow-response A (dBA) above background noise levels and that occurred during infants' sleep varied significantly, indicating that VPIs detect them. Exposure to 10-15 dBA SPs during active sleep significantly increased mean heart rate and decreased mean respiratory rate and mean systemic and cerebral oxygen saturations relative to baseline. VPIs are sensitive to changes in their nosocomial acoustic environment, with a minimal signal-to-noise ratio (SNR) threshold of 5-10 dBA. These acoustic changes can alter their well-being. In this observational study, we evaluated their differential auditory sensitivity to sound-pressure level (SPL) increments below 70-75 dBA equivalent continuous level in their incubators. Environmental (SPL and audio recording), physiological, cerebral, and behavioral data were prospectively collected over 10 h in 26 VPIs (GA 28 (26-31) wk). SPs emerging from background noise levels were identified and newborns' arousal states at the time of SPs were determined. Changes in parameters were compared over 5-s periods between baseline and the 40 s following the SPs depending on their SNR thresholds above background noise.

Geospatial association between adverse birth outcomes and arsenic in groundwater in New Hampshire, USA

USGS Publications Warehouse

Xun Shi,; Ayotte, Joseph; Akikazu Onda,; Stephanie Miller,; Judy Rees,; Diane Gilbert-Diamond,; Onega, Tracy L; Gui, Jiang; Karagas, Margaret R.; Moeschler, John B

2015-01-01

There is increasing evidence of the role of arsenic in the etiology of adverse human reproductive outcomes. Because drinking water can be a major source of arsenic to pregnant women, the effect of arsenic exposure through drinking water on human birth may be revealed by a geospatial association between arsenic concentration in groundwater and birth problems, particularly in a region where private wells substantially account for water supply, like New Hampshire, USA. We calculated town-level rates of preterm birth and term low birth weight (term LBW) for New Hampshire, by using data for 1997–2009 stratified by maternal age. We smoothed the rates by using a locally weighted averaging method to increase the statistical stability. The town-level groundwater arsenic probability values are from three GIS data layers generated by the US Geological Survey: probability of local groundwater arsenic concentration >1 µg/L, probability >5 µg/L, and probability >10 µg/L. We calculated Pearson’s correlation coefficients (r) between the reproductive outcomes (preterm birth and term LBW) and the arsenic probability values, at both state and county levels. For preterm birth, younger mothers (maternal age <20) have a statewider = 0.70 between the rates smoothed with a threshold = 2,000 births and the town mean arsenic level based on the data of probability >10 µg/L; for older mothers, r = 0.19 when the smoothing threshold = 3,500; a majority of county level r values are positive based on the arsenic data of probability >10 µg/L. For term LBW, younger mothers (maternal age <25) have a statewide r = 0.44 between the rates smoothed with a threshold = 3,500 and town minimum arsenic concentration based on the data of probability >1 µg/L; for older mothers, r = 0.14 when the rates are smoothed with a threshold = 1,000 births and also adjusted by town median household income in 1999, and the arsenic values are the town minimum based on probability >10 µg/L. At the county level for younger mothers, positive r values prevail, but for older mothers, it is a mix. For both birth problems, the several most populous counties—with 60–80% of the state’s population and clustering at the southwest corner of the state—are largely consistent in having a positive r across different smoothing thresholds. We found evident spatial associations between the two adverse human reproductive outcomes and groundwater arsenic in New Hampshire, USA. However, the degree of associations and their sensitivity to different representations of arsenic level are variable. Generally, preterm birth has a stronger spatial association with groundwater arsenic than term LBW, suggesting an inconsistency in the impact of arsenic on the two reproductive outcomes. For both outcomes, younger maternal age has stronger spatial associations with groundwater arsenic.

Internal validation of the GlobalFiler™ Express PCR Amplification Kit for the direct amplification of reference DNA samples on a high-throughput automated workflow.

PubMed

Flores, Shahida; Sun, Jie; King, Jonathan; Budowle, Bruce

2014-05-01

The GlobalFiler™ Express PCR Amplification Kit uses 6-dye fluorescent chemistry to enable multiplexing of 21 autosomal STRs, 1 Y-STR, 1 Y-indel and the sex-determining marker amelogenin. The kit is specifically designed for processing reference DNA samples in a high throughput manner. Validation studies were conducted to assess the performance and define the limitations of this direct amplification kit for typing blood and buccal reference DNA samples on various punchable collection media. Studies included thermal cycling sensitivity, reproducibility, precision, sensitivity of detection, minimum detection threshold, system contamination, stochastic threshold and concordance. Results showed that optimal amplification and injection parameters for a 1.2mm punch from blood and buccal samples were 27 and 28 cycles, respectively, combined with a 12s injection on an ABI 3500xL Genetic Analyzer. Minimum detection thresholds were set at 100 and 120RFUs for 27 and 28 cycles, respectively, and it was suggested that data from positive amplification controls provided a better threshold representation. Stochastic thresholds were set at 250 and 400RFUs for 27 and 28 cycles, respectively, as stochastic effects increased with cycle number. The minimum amount of input DNA resulting in a full profile was 0.5ng, however, the optimum range determined was 2.5-10ng. Profile quality from the GlobalFiler™ Express Kit and the previously validated AmpFlSTR(®) Identifiler(®) Direct Kit was comparable. The validation data support that reliable DNA typing results from reference DNA samples can be obtained using the GlobalFiler™ Express PCR Amplification Kit. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

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... prices for their parcels when they pay postage by any of the following three methods: Permit imprint... permit imprint, meet specific mailing requirements, and whose account volume exceeds a minimum threshold... prices in a calendar year. Pay for postage using a permit imprint. Enter a minimum of 500 pieces of mail...

Re-examination of immune response and estimation of anti-Vi IgG protective threshold against typhoid fever-based on the efficacy trial of Vi conjugate in young children

PubMed Central

Szu, Shousun C.; Klugman, Keith P.; Hunt, Steven

2014-01-01

Background The capsular polysaccharide of Salmonella enterica serovar Typhi, Vi antigen, is an essential virulence factor and a protective antigen. Similar to other polysaccharide vaccines, the protective action of Vi, both to the polysaccharide alone or when presented as a conjugate, is mediated by serum IgG Vi antibodies. The evaluation of Vi capsular polysaccharide based vaccines to prevent typhoid fever would be significantly facilitated by the identification of a “protective level” of serum antibodies to Vi antigen. Methods The protective level of anti-Vi IgG against typhoid fever was derived from the protective efficacy and immune response of a Vi-rEPA conjugate vaccine efficacy trial. The estimation was derived by two methods: correlation of the percent efficacy and the antibody distribution profile in the vaccine group at a given period of observation, and use of the relative ratio of anti-Vi IgG levels between the vaccine and placebo groups greater or equal to the Relative Risk of typhoid fever used in the efficacy determination. Results Both methods predicted a similar range of a minimum protective level of anti-Vi IgG between 1.4 and 2.0 μg/ml (short term threshold). When applying a protective threshold of 10 μg/ml at 6 months post immunization, an IgG level in excess of 1.4 μg/ml was achieved by 90% of children at 46 months post immunization, consistent with an 89% level of protection over the duration of the study. We thus suggest that the proportion of children with Vi IgG > 10 μg/ml (long term threshold) 6 months after immunization may reflect the proportion protected over at least a 4 year period. Conclusion The current assignment of an anti-Vi IgG protective level may be of value when evaluating vaccine performance of future Vi conjugate vaccines. PMID:24630869

Lane change warning threshold based on driver perception characteristics.

PubMed

Wang, Chang; Sun, Qinyu; Fu, Rui; Li, Zhen; Zhang, Qiong

2018-08-01

Lane Change Warning system (LCW) is exploited to alleviate driver workload and improve the safety performance of lane changes. Depending on the secure threshold, the lane change warning system could transmit caution to drivers. Although the system possesses substantial benefits, it may perturb the conventional operating of the driver and affect driver judgment if the warning threshold does not conform to the driver perception of safety. Therefore, it is essential to establish an appropriate warning threshold to enhance the accuracy rate and acceptability of the lane change warning system. This research aims to identify the threshold that conforms to the driver perception of the ability to safely change lanes with a rear vehicle fast approaching. We propose a theoretical warning model of lane change based on a safe minimum distance and deceleration of the rear vehicle. For the purpose of acquiring the different safety levels of lane changes, 30 licensed drivers are recruited and we obtain the extreme moments represented by driver perception characteristics from a Front Extremity Test and a Rear Extremity Test implemented on the freeway. The required deceleration of the rear vehicle corresponding to the extreme time is calculated according to the proposed model. In light of discrepancies in the deceleration in these extremity experiments, we determine two levels of a hierarchical warning system. The purpose of the primary warning is to remind drivers of the existence of potentially dangerous vehicles and the second warning is used to warn the driver to stop changing lanes immediately. We use the signal detection theory to analyze the data. Ultimately, we confirm that the first deceleration threshold is 1.5 m/s 2 and the second deceleration threshold is 2.7 m/s 2 . The findings provide the basis for the algorithm design of LCW and enhance the acceptability of the intelligent system. Copyright © 2018 Elsevier Ltd. All rights reserved.

Short time variability of solar corona during recent solar cycle minimum

NASA Astrophysics Data System (ADS)

Siarkowski, Marek; Gryciuk, Magdalena; Gburek, Szymon; Sylwester, Janusz; Sylwester, Barbara; Kepa, Anna; Buczkowska, Agnieszka; Kowalinski, Miroslaw

Sphinx is the X-ray spectrophotometer designed to measure X-ray emission from the Sun in the energy range between 0.8 keV and 15 keV. The instrument is placed onboard Russian KORONAS-PHOTON satellite launched on January 30, 2009. In this paper we present the observations of coronal emission obtained between March-April and August-September 2009, i.e. the times towards the end of the last, very prolonged and deep minimum of solar activity. Prompt analysis of SphinX spectra reveal the variability of the average coronal plasma charac-teristics like the temperature and emission measure. These data are used to compare SphinX and GOES measurements, for selected times. Examples of many sub/microflare events with maxima of the X-ray flux, observed much below the GOES sensitivity threshold level will be presented.

Differential detection of Gaussian MSK in a mobile radio environment

NASA Technical Reports Server (NTRS)

Simon, M. K.; Wang, C. C.

1984-01-01

Minimum shift keying with Gaussian shaped transmit pulses is a strong candidate for a modulation technique that satisfies the stringent out-of-band radiated power requirements of the mobil radio application. Numerous studies and field experiments have been conducted by the Japanese on urban and suburban mobile radio channels with systems employing Gaussian minimum-shift keying (GMSK) transmission and differentially coherent reception. A comprehensive analytical treatment is presented of the performance of such systems emphasizing the important trade-offs among the various system design parameters such as transmit and receiver filter bandwidths and detection threshold level. It is shown that two-bit differential detection of GMSK is capable of offering far superior performance to the more conventional one-bit detection method both in the presence of an additive Gaussian noise background and Rician fading.

Differential detection of Gaussian MSK in a mobile radio environment

NASA Astrophysics Data System (ADS)

Simon, M. K.; Wang, C. C.

1984-11-01

Minimum shift keying with Gaussian shaped transmit pulses is a strong candidate for a modulation technique that satisfies the stringent out-of-band radiated power requirements of the mobil radio application. Numerous studies and field experiments have been conducted by the Japanese on urban and suburban mobile radio channels with systems employing Gaussian minimum-shift keying (GMSK) transmission and differentially coherent reception. A comprehensive analytical treatment is presented of the performance of such systems emphasizing the important trade-offs among the various system design parameters such as transmit and receiver filter bandwidths and detection threshold level. It is shown that two-bit differential detection of GMSK is capable of offering far superior performance to the more conventional one-bit detection method both in the presence of an additive Gaussian noise background and Rician fading.

Optical ranked-order filtering using threshold decomposition

DOEpatents

Allebach, J.P.; Ochoa, E.; Sweeney, D.W.

1987-10-09

A hybrid optical/electronic system performs median filtering and related ranked-order operations using threshold decomposition to encode the image. Threshold decomposition transforms the nonlinear neighborhood ranking operation into a linear space-invariant filtering step followed by a point-to-point threshold comparison step. Spatial multiplexing allows parallel processing of all the threshold components as well as recombination by a second linear, space-invariant filtering step. An incoherent optical correlation system performs the linear filtering, using a magneto-optic spatial light modulator as the input device and a computer-generated hologram in the filter plane. Thresholding is done electronically. By adjusting the value of the threshold, the same architecture is used to perform median, minimum, and maximum filtering of images. A totally optical system is also disclosed. 3 figs.

High voltage threshold for stable operation in a dc electron gun

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamamoto, Masahiro, E-mail: masahiro@post.kek.jp; Nishimori, Nobuyuki, E-mail: n-nishim@tagen.tohoku.ac.jp

We report clear observation of a high voltage (HV) threshold for stable operation in a dc electron gun. The HV hold-off time without any discharge is longer than many hours for operation below the threshold, while it is roughly 10 min above the threshold. The HV threshold corresponds to the minimum voltage where discharge ceases. The threshold increases with the number of discharges during HV conditioning of the gun. Above the threshold, the amount of gas desorption per discharge increases linearly with the voltage difference from the threshold. The present experimental observations can be explained by an avalanche discharge modelmore » based on the interplay between electron stimulated desorption (ESD) from the anode surface and subsequent secondary electron emission from the cathode by the impact of ionic components of the ESD molecules or atoms.« less

Longitudinal Comparison of Auditory Steady-State Evoked Potentials in Preterm and Term Infants: The Maturation Process

PubMed Central

Sousa, Ana Constantino; Didoné, Dayane Domeneghini; Sleifer, Pricila

2017-01-01

Introduction  Preterm neonates are at risk of changes in their auditory system development, which explains the need for auditory monitoring of this population. The Auditory Steady-State Response (ASSR) is an objective method that allows obtaining the electrophysiological thresholds with greater applicability in neonatal and pediatric population. Objective  The purpose of this study is to compare the ASSR thresholds in preterm and term infants evaluated during two stages. Method  The study included 63 normal hearing neonates: 33 preterm and 30 term. They underwent assessment of ASSR in both ears simultaneously through insert phones in the frequencies of 500 to 4000Hz with the amplitude modulated from 77 to 103Hz. We presented the intensity at a decreasing level to detect the minimum level of responses. At 18 months, 26 of 33 preterm infants returned for the new assessment for ASSR and were compared with 30 full-term infants. We compared between groups according to gestational age. Results  Electrophysiological thresholds were higher in preterm than in full-term neonates ( p  < 0.05) at the first testing. There were no significant differences between ears and gender. At 18 months, there was no difference between groups ( p  > 0.05) in all the variables described. Conclusion  In the first evaluation preterm had higher thresholds in ASSR. There was no difference at 18 months of age, showing the auditory maturation of preterm infants throughout their development. PMID:28680486

A fuzzy optimal threshold technique for medical images

NASA Astrophysics Data System (ADS)

Thirupathi Kannan, Balaji; Krishnasamy, Krishnaveni; Pradeep Kumar Kenny, S.

2012-01-01

A new fuzzy based thresholding method for medical images especially cervical cytology images having blob and mosaic structures is proposed in this paper. Many existing thresholding algorithms may segment either blob or mosaic images but there aren't any single algorithm that can do both. In this paper, an input cervical cytology image is binarized, preprocessed and the pixel value with minimum Fuzzy Gaussian Index is identified as an optimal threshold value and used for segmentation. The proposed technique is tested on various cervical cytology images having blob or mosaic structures, compared with various existing algorithms and proved better than the existing algorithms.

Measurement with verification of stationary signals and noise in extremely quiet environments: Measuring below the noise floor

PubMed Central

Ellingson, Roger M.; Gallun, Frederick J.; Bock, Guillaume

2015-01-01

It can be problematic to measure stationary acoustic sound pressure level in any environment when the target level approaches or lies below the minimum measureable sound pressure level of the measurement system itself. This minimum measureable level, referred to as the inherent measurement system noise floor, is generally established by noise emission characteristics of measurement system components such as microphones, preamplifiers, and other system circuitry. In this paper, methods are presented and shown accurate measuring stationary levels within 20 dB above and below this system noise floor. Methodology includes (1) measuring inherent measurement system noise, (2) subtractive energy based, inherent noise adjustment of levels affected by system noise floor, and (3) verifying accuracy of inherent noise adjustment technique. While generalizable to other purposes, the techniques presented here were specifically developed to quantify ambient noise levels in very quiet rooms used to evaluate free-field human hearing thresholds. Results obtained applying the methods to objectively measure and verify the ambient noise level in an extremely quiet room, using various measurement system noise floors and analysis bandwidths, are presented and discussed. The verified results demonstrate the adjustment method can accurately extend measurement range to 20 dB below the measurement system noise floor, and how measurement system frequency bandwidth can affect accuracy of reported noise levels. PMID:25786932

78 FR 28692 - Self-Regulatory Organizations; BOX Options Exchange LLC; Notice of Filing and Immediate...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-15

... standard SPY options, (2) codify the minimum contract threshold requirement for the execution of Jumbo SPY... Fund (``IWM''). QQQQ, SPY and IWM are quoted in $0.01 increments for all options series. This proposed... Exchange believes that by reducing the minimum trading increments for Jumbo SPY Options to $0.01, the...

Transient impairment of olfactory threshold in acute multiple sclerosis relapse.

PubMed

Bsteh, Gabriel; Hegen, Harald; Ladstätter, Felix; Berek, Klaus; Amprosi, Matthias; Wurth, Sebastian; Auer, Michael; Di Pauli, Franziska; Deisenhammer, Florian; Lutterotti, Andreas; Berger, Thomas

2018-05-18

Impairment of olfactory threshold is a feature of early and active relapsing remitting multiple sclerosis (RRMS). It predicts inflammatory disease activity and was reported to be transient. However, the timing of onset and resolve of olfactory threshold impairment remains unclear. To prospectively assess the development of olfactory threshold in acute MS relapse over time in comparison to stable MS patients. In a prospective observational design, we measured olfactory threshold by performing the Sniffin' Sticks test (minimum score 0, maximum score 16 reflecting optimal olfactory function) at baseline and after 4, 12 and 24 weeks. We included 30 RRMS patients with acute MS relapse and 30 clinically stable RRMS patients (defined as no relapse within the last 12 months) as a control group. Olfactory threshold was impaired in patients with acute MS relapse at baseline (median difference = -3.5; inter-quartile range [IQR] -4.5- - 2.5; p < 0.001), week 4 (-2.5; IQR -3.0 - -2.0; p < 0.001), week 12 (-1.5; IQR -2.0 - -0.5; p = 0.002) and week 24 (-0.5; IQR -1.0 - 0.0; p = 0.159) compared to stable MS patients. Of note, in relapsing patients in whom disease-modifying treatment was initiated or escalated after relapse, threshold did not differ anymore from stable patients at week 12 (-0.5; IQR -1.0 - 0.5; p = 0.247) and week 24 (0.0; IQR -1.0 - 1.0; p = 0.753). Olfactory threshold impairment seems to be a transient bystander feature of MS relapse. It may be correlated to the level of inflammation within the CNS and might be a useful biomarker in this regard. Copyright © 2018 Elsevier B.V. All rights reserved.

Chaotic Signal Denoising Based on Hierarchical Threshold Synchrosqueezed Wavelet Transform

NASA Astrophysics Data System (ADS)

Wang, Wen-Bo; Jing, Yun-yu; Zhao, Yan-chao; Zhang, Lian-Hua; Wang, Xiang-Li

2017-12-01

In order to overcoming the shortcoming of single threshold synchrosqueezed wavelet transform(SWT) denoising method, an adaptive hierarchical threshold SWT chaotic signal denoising method is proposed. Firstly, a new SWT threshold function is constructed based on Stein unbiased risk estimation, which is two order continuous derivable. Then, by using of the new threshold function, a threshold process based on the minimum mean square error was implemented, and the optimal estimation value of each layer threshold in SWT chaotic denoising is obtained. The experimental results of the simulating chaotic signal and measured sunspot signals show that, the proposed method can filter the noise of chaotic signal well, and the intrinsic chaotic characteristic of the original signal can be recovered very well. Compared with the EEMD denoising method and the single threshold SWT denoising method, the proposed method can obtain better denoising result for the chaotic signal.

Dynamic Self-adaptive Remote Health Monitoring System for Diabetics

PubMed Central

Suh, Myung-kyung; Moin, Tannaz; Woodbridge, Jonathan; Lan, Mars; Ghasemzadeh, Hassan; Bui, Alex; Ahmadi, Sheila; Sarrafzadeh, Majid

2016-01-01

Diabetes is the seventh leading cause of death in the United States. In 2010, about 1.9 million new cases of diabetes were diagnosed in people aged 20 years or older. Remote health monitoring systems can help diabetics and their healthcare professionals monitor health-related measurements by providing real-time feedback. However, data-driven methods to dynamically prioritize and generate tasks are not well investigated in the remote health monitoring. This paper presents a task optimization technique used in WANDA (Weight and Activity with Blood Pressure and Other Vital Signs); a wireless health project that leverages sensor technology and wireless communication to monitor the health status of patients with diabetes. WANDA applies data analytics in real-time to improving the quality of care. The developed algorithm minimizes the number of daily tasks required by diabetic patients using association rules that satisfies a minimum support threshold. Each of these tasks maximizes information gain, thereby improving the overall level of care. Experimental results show that the developed algorithm can reduce the number of tasks up to 28.6% with minimum support 0.95, minimum confidence 0.97 and high efficiency. PMID:23366365

Effect of resiniferatoxin on the noxious heat threshold temperature in the rat: a novel heat allodynia model sensitive to analgesics

PubMed Central

Almási, Róbert; Pethö, Gábor; Bölcskei, Kata; Szolcsányi, János

2003-01-01

An increasing-temperature hot plate (ITHP) was introduced to measure the noxious heat threshold (45.3±0.3°C) of unrestrained rats, which was reproducible upon repeated determinations at intervals of 5 or 30 min or 1 day. Morphine, diclofenac and paracetamol caused an elevation of the noxious heat threshold following i.p. pretreatment, the minimum effective doses being 3, 10 and 200 mg kg−1, respectively. Unilateral intraplantar injection of the VR1 receptor agonist resiniferatoxin (RTX, 0.048 nmol) induced a profound drop of heat threshold to the innocuous range with a maximal effect (8–10°C drop) 5 min after RTX administration. This heat allodynia was inhibited by pretreatment with morphine, diclofenac and paracetamol, the minimum effective doses being 1, 1 and 100 mg kg−1 i.p., respectively. The long-term sensory desensitizing effect of RTX was examined by bilateral intraplantar injection (0.048 nmol per paw) which produced, after an initial threshold drop, an elevation (up to 2.9±0.5°C) of heat threshold lasting for 5 days. The VR1 receptor antagonist iodo-resiniferatoxin (I-RTX, 0.05 nmol intraplantarly) inhibited by 51% the heat threshold-lowering effect of intraplantar RTX but not α,β-methylene-ATP (0.3 μmol per paw). I-RTX (0.1 or 1 nmol per paw) failed to alter the heat threshold either acutely (5–60 min) or on the long-term (5 days). The heat threshold of VR1 receptor knockout mice was not different from that of wild-type animals (45.6±0.5 vs 45.2±0.4°C). In conclusion, the RTX-induced drop of heat threshold measured by the ITHP is a novel heat allodynia model exhibiting a high sensitivity to analgesics. PMID:12746222

The effect of pre-test carbohydrate ingestion on the anaerobic threshold, as determined by the lactate-minimum test.

PubMed

Rotstein, Arie; Dotan, Raffy; Zigel, Levana; Greenberg, Tally; Benyamini, Yael; Falk, Bareket

2007-12-01

The purpose of this study was to investigate the effect of pre-test carbohydrate (CHO) ingestion on anaerobic-threshold assessment using the lactate-minimum test (LMT). Fifteen competitive male distance runners capable of running 10 km in 33.5-43 min were used as subjects. LMT was performed following CHO (2x300 mL, 7% solution) or comparable placebo (Pl) ingestion, in a double-blind, randomized order. The LMT consisted of two high-intensity 1 min treadmill runs (17-21 km.h(-1)), followed by an 8 min recovery period. Subsequently, subjects performed 5 min running stages, incremented by 0.6 km.h(-1) and separated by 1 min blood-sampling intervals. Tests were terminated after 3 consecutive increases in blood-lactate concentration ([La]) had been observed. Finger-tip capillary blood was sampled for [La] and blood-glucose determination 30 min before the test's onset, during the recovery phase following the 2 high-intensity runs, and following each of the subsequent 5 min stages. Heart rate (HR) and rating of perceived exertion (RPE) were recorded after each stage. The lactate-minimum speed (LMS) was determined from the individual [La]-velocity plots and was considered reflective of the anaerobic threshold. Pre-test CHO ingestion had no effect on LMS (13.19+/-1.12 km.h(-1) vs. 13.17+/-1.08 km.h(-1) in CHO and Pl, respectively), nor on [La] and glucose concentration at that speed, or on HR and RPE responses. Pre-test CHO ingestion therefore does not affect LMS or the LMT-estimated anaerobic threshold.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnstone, Peter; Jacobson, Arne; Mills, Evan

Creation of light for work, socializing, and general illumination is a fundamental application of technology around the world. For those who lack access to electricity, an emerging and diverse range of LED based lighting products hold promise for replacing and/or augmenting their current fuel-based lighting sources that are costly and dirty. Along with analysis of environmental factors, economic models for total cost-ofownership of LED lighting products are an important tool for studying the impacts of these products as they emerge in markets of developing countries. One important metric in those models is the minimum illuminance demanded by end-users for amore » given task before recharging the lamp or replacing batteries. It impacts the lighting service cost per unit time if charging is done with purchased electricity, batteries, or charging services. The concept is illustrated in figure 1: LED lighting products are generally brightest immediately after the battery is charged or replaced and the illuminance degrades as the battery is discharged. When a minimum threshold level of illuminance is reached, the operational time for the battery charge cycle is over. The cost to recharge depends on the method utilized; these include charging at a shop at a fixed price per charge, charging on personal grid connections, using solar chargers, and purchasing dry cell batteries. This Research Note reports on the observed"charge-triggering" illuminance level threshold for night market vendors who use LED lighting products to provide general and task oriented illumination. All the study participants charged with AC power, either at a fixed-price charge shop or with electricity at their home.« less

Associations between frequency of bullying involvement and adjustment in adolescence.

PubMed

Gower, Amy L; Borowsky, Iris W

2013-01-01

To examine whether infrequent bullying perpetration and victimization (once or twice a month) are associated with elevated levels of internalizing and externalizing problems and to assess evidence for a minimum frequency threshold for bullying involvement. The analytic sample included 128,681 6th, 9th, and 12th graders who completed the 2010 Minnesota Student Survey. Logistic regression and general linear models examined the association between bullying frequency and adjustment correlates including emotional distress, self-harm, physical fighting, and substance use while controlling for demographic characteristics. Gender and grade were included as moderators. Infrequent bullying perpetration and victimization were associated with increased levels of all adjustment problems relative to those who did not engage in bullying in the past 30 days. Grade moderated many of these findings, with perpetration frequency being more strongly related to substance use, self-harm, and suicidal ideation for 6th graders than 12th graders, whereas victimization frequency was associated with self-harm more strongly for 12th graders than 6th graders. Evidence for minimum thresholds for bullying involvement across all outcomes, grades, and bullying roles was inconsistent. Infrequent bullying involvement may pose risks to adolescent adjustment; thus, clinicians and school personnel should address even isolated instances of bullying behavior. Researchers should reexamine the use of cut points in bullying research in order to more fully understand the nature of bullying in adolescence. These data indicate the need for prevention and intervention programs that target diverse internalizing and externalizing problems for bullies and victims, regardless of bullying frequency. Copyright © 2013 Academic Pediatric Association. Published by Elsevier Inc. All rights reserved.

Ab initio molecular dynamics simulations of low energy recoil events in MgO

DOE PAGES

Petersen, B. A.; Liu, B.; Weber, W. J.; ...

2017-01-11

In this paper, low-energy recoil events in MgO are studied using ab initio molecular dynamics simulations to reveal the dynamic displacement processes and final defect configurations. Threshold displacement energies, E d, are obtained for Mg and O along three low-index crystallographic directions, [100], [110], and [111]. The minimum values for E d are found along the [110] direction consisting of the same element, either Mg or O atoms. Minimum threshold values of 29.5 eV for Mg and 25.5 eV for O, respectively, are suggested from the calculations. For other directions, the threshold energies are considerably higher, 65.5 and 150.0 eVmore » for O along [111] and [100], and 122.5 eV for Mg along both [111] and [100] directions, respectively. These results show that the recoil events in MgO are partial-charge transfer assisted processes where the charge transfer plays an important role. Finally, there is a similar trend found in other oxide materials, where the threshold displacement energy correlates linearly with the peak partial-charge transfer, suggesting this behavior might be universal in ceramic oxides.« less

Low threshold Amplified Spontaneous Emission properties in deep blue of poly[(9,9-dioctylfluorene-2,7-dyil)-alt-p-phenylene] thin films

NASA Astrophysics Data System (ADS)

Lattante, Sandro; De Giorgi, Maria Luisa; Pasini, Mariacecilia; Anni, Marco

2017-10-01

Amongst the different optoelectronic applications of conjugated polymers, the development of new active materials for optically pumped organic lasers is still an open question particularly in the blue-near UV spectral range. We investigate the emission properties of poly[(9,9-dioctylfluorene-2,7-dyil)- alt-p-phenylene] (PFP) neat films under nanosecond pump. We demonstrate that thanks to the introduction of a phenylene moiety between two fluorene units it is possible to obtain Amplified Spontaneous Emission (ASE) with a lower threshold and a blue shifted wavelength with respect to poly(9,9-dioctylfluorene) (PFO). We demonstrate efficient ASE with a minimum threshold as low as 23 μJcm-2 and a minimum ASE wavelength of 436 nm. A maximum net optical gain of about 26 cm-1 is measured at an excitation density of 0.23 mJcm-2. These results make the PFP a good active material for optically pumped deep blue organic lasers.

Trophy Hunting and Sustainability: Temporal Dynamics in Trophy Quality and Harvesting Patterns of Wild Herbivores in a Tropical Semi-Arid Savanna Ecosystem.

PubMed

Muposhi, Victor K; Gandiwa, Edson; Bartels, Paul; Makuza, Stanley M; Madiri, Tinaapi H

2016-01-01

The selective nature of trophy hunting may cause changes in desirable phenotypic traits in harvested species. A decline in trophy size of preferred species may reduce hunting destination competitiveness thus compromising the sustainability of trophy hunting as a conservation tool. We explored the trophy quality and trends in harvesting patterns (i.e., 2004-2015) of Cape buffalo (Syncerus caffer), African elephant (Loxodonta africana), greater kudu (Tragelaphus strepsiceros) and sable (Hippotragus niger) in Matetsi Safari Area, northwest Zimbabwe. We used long-term data on horn and tusk size, age, quota size allocation and offtake levels of selected species. To analyse the effect of year, area and age on the trophy size, quota size and offtake levels, we used linear mixed models. One sample t-test was used to compare observed trophy size with Safari Club International (SCI) minimum score. Trophy sizes for Cape buffalo and African elephant were below the SCI minimum score. Greater kudu trophy sizes were within the minimum score threshold whereas sable trophy sizes were above the SCI minimum score between 2004 and 2015. Age at harvest for Cape buffalo, kudu and sable increased whilst that of elephant remained constant between 2004 and 2015. Quota size allocated for buffalo and the corresponding offtake levels declined over time. Offtake levels of African elephant and Greater kudu declined whilst the quota size did not change between 2004 and 2015. The quota size for sable increased whilst the offtake levels fluctuated without changing for the period 2004-2015. The trophy size and harvesting patterns in these species pose a conservation and management dilemma on the sustainability of trophy hunting in this area. We recommend: (1) temporal and spatial rotational resting of hunting areas to create refuge to improve trophy quality and maintenance of genetic diversity, and (2) introduction of variable trophy fee pricing system based on trophy size.

Visible lesion laser thresholds in Cynomolgus (Macaca fascicularis) retina with a 1064 nm 12-ns pulsed laser

NASA Astrophysics Data System (ADS)

Oliver, Jeffrey W.; Stolarski, David J.; Noojin, Gary D.; Hodnett, Harvey M.; Imholte, Michelle L.; Rockwell, Benjamin A.; Kumru, Semih S.

2007-02-01

A series of experiments in a new animal model for retinal damage, cynomolgus monkeys (Macaca fascicularis), have been conducted to determine the damage threshold for 12.5-nanosecond laser exposures at 1064 nm. These results provide a direct comparison to threshold values obtained in rhesus monkey (Macaca mulatta), which is the model historically used in establishing retinal maximum permissible exposure (MPE) limits. In this study, the irradiance level of a collimated Gaussian laser beam of 2.5 mm diameter at the cornea was randomly varied to produce a rectangular grid of exposures on the retina. Exposures sites were fundoscopically evaluated at post-irradiance intervals of 1 hour and 24 hours. Probit analysis was performed on dose-response data to obtain probability of response curves. The 50% probability of damage (ED50) values for 1 and 24 hours post-exposure are 28.5(22.7-38.4) μJ and 17.0(12.9-21.8) μJ, respectively. These values compare favorably to data obtained with the rhesus model, 28.7(22.3-39.3) μJ and 19.1(13.6-24.4) μJ, suggesting that the cynomolgus monkey may be a suitable replacement for rhesus monkey in photoacoustic minimum visible lesion threshold studies.

A minimum of 3 months of dietary fish oil supplementation is required to raise amygdaloid afterdischarge seizure thresholds in rats--implications for treating complex partial seizures.

PubMed

Taha, Ameer Y; Trepanier, Marc-Olivier; Ciobanu, Flaviu A; Taha, Nadeen M; Ahmed, Muaz; Zeng, Qiudi; Cheuk, Waiyin I; Ip, Bryan; Filo, Elvis; Scott, Brian W; Burnham, W M; Bazinet, Richard P

2013-04-01

Complex partial seizures, which typically originate in limbic structures such as the amygdala, are often resistant to antiseizure medications. Our goal was to investigate the effects of chronic dietary supplementation with n-3 polyunsaturated fatty acids (PUFAs) derived from fish oil on seizure thresholds in the amygdala, as well as on blood and brain PUFA levels. The acute effects of injected n-3 PUFAs--eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)--were also tested in the maximal pentylenetetrazol (PTZ) seizure model. In amygdala-implanted subjects, fish oil supplementation significantly increased amygdaloid afterdischarge thresholds, as compared with controls at 3, 5, and 7 months after the start of supplementation. Fish oil supplementation also increased serum EPA and DHA concentrations. DHA concentration in the pyriform-amygdala area increased in the fish-oil treated group by 17-34%, but this effect did not reach statistical significance (P=0.065). DHA significantly increased the latency to seizure onset in the PTZ seizure model, whereas EPA had no significant effect. These observations suggest that chronic dietary fish oil supplementation can raise focal amygdaloid seizure thresholds and that this effect is likely mediated by DHA rather than by EPA. Copyright © 2012 Elsevier Inc. All rights reserved.

49 CFR 38.153 - Doors, steps and thresholds.

Code of Federal Regulations, 2011 CFR

2011-10-01

...)(1) Doors shall have a minimum clear width when open of 30 inches (760 mm), measured from the lowest step to a height of at least 48 inches (1220 mm), from which point they may taper to a minimum width of 18 inches (457 mm). The clear width may be reduced by a maximum of 4 inches (100 mm) by protrusions...

49 CFR 38.153 - Doors, steps and thresholds.

Code of Federal Regulations, 2014 CFR

2014-10-01

...)(1) Doors shall have a minimum clear width when open of 30 inches (760 mm), measured from the lowest step to a height of at least 48 inches (1220 mm), from which point they may taper to a minimum width of 18 inches (457 mm). The clear width may be reduced by a maximum of 4 inches (100 mm) by protrusions...

36 CFR § 1192.153 - Doors, steps and thresholds.

Code of Federal Regulations, 2013 CFR

2013-07-01

... have a minimum clear width when open of 30 inches (760 mm), measured from the lowest step to a height of at least 48 inches (1220 mm), from which point they may taper to a minimum width of 18 inches (457 mm). The clear width may be reduced by a maximum of 4 inches (100 mm) by protrusions of hinges or...

36 CFR 1192.153 - Doors, steps and thresholds.

Code of Federal Regulations, 2012 CFR

2012-07-01

... minimum clear width when open of 30 inches (760 mm), measured from the lowest step to a height of at least 48 inches (1220 mm), from which point they may taper to a minimum width of 18 inches (457 mm). The clear width may be reduced by a maximum of 4 inches (100 mm) by protrusions of hinges or other operating...

49 CFR 38.153 - Doors, steps and thresholds.

Code of Federal Regulations, 2013 CFR

2013-10-01

...)(1) Doors shall have a minimum clear width when open of 30 inches (760 mm), measured from the lowest step to a height of at least 48 inches (1220 mm), from which point they may taper to a minimum width of 18 inches (457 mm). The clear width may be reduced by a maximum of 4 inches (100 mm) by protrusions...

36 CFR 1192.153 - Doors, steps and thresholds.

Code of Federal Regulations, 2014 CFR

2014-07-01

... minimum clear width when open of 30 inches (760 mm), measured from the lowest step to a height of at least 48 inches (1220 mm), from which point they may taper to a minimum width of 18 inches (457 mm). The clear width may be reduced by a maximum of 4 inches (100 mm) by protrusions of hinges or other operating...

36 CFR 1192.153 - Doors, steps and thresholds.

Code of Federal Regulations, 2011 CFR

2011-07-01

... minimum clear width when open of 30 inches (760 mm), measured from the lowest step to a height of at least 48 inches (1220 mm), from which point they may taper to a minimum width of 18 inches (457 mm). The clear width may be reduced by a maximum of 4 inches (100 mm) by protrusions of hinges or other operating...

49 CFR 38.153 - Doors, steps and thresholds.

Code of Federal Regulations, 2012 CFR

2012-10-01

...)(1) Doors shall have a minimum clear width when open of 30 inches (760 mm), measured from the lowest step to a height of at least 48 inches (1220 mm), from which point they may taper to a minimum width of 18 inches (457 mm). The clear width may be reduced by a maximum of 4 inches (100 mm) by protrusions...

The range of minimum provoking doses in hazelnut-allergic patients as determined by double-blind, placebo-controlled food challenges.

PubMed

Wensing, M; Penninks, A H; Hefle, S L; Akkerdaas, J H; van Ree, R; Koppelman, S J; Bruijnzeel-Koomen, C A F M; Knulst, A C

2002-12-01

The risk for allergic reactions depends on the sensitivity of individuals and the quantities of offending food ingested. The sensitivity varies among allergic individuals, as does the threshold dose of a food allergen capable of inducing an allergic reaction. This study aimed at determining the distribution of minimum provoking doses of hazelnut in a hazelnut-allergic population. Thirty-one patients with a history of hazelnut-related allergic symptoms, a positive skin prick test to hazelnut and/or an elevated specific IgE level, were included. Double-blind, placebo-controlled food challenges (DBPCFC) were performed with seven increasing doses of dried hazelnut (1 mg to 1 g hazelnut protein) randomly interspersed with seven placebo doses. Twenty-nine patients had a positive challenge. Itching of the oral cavity and/or lips was the first symptom in all cases. Additional gastrointestinal symptoms were reported in five patients and difficulty in swallowing in one patient. Lip swelling was observed in two patients, followed by generalized urticaria in one of these. Threshold doses for eliciting subjective reactions varied from a dose of 1 mg up to 100 mg hazelnut protein (equivalent to 6.4-640 mg hazelnut meal). Extrapolation of the dose-response curve showed that 50% of our hazelnut-allergic population will suffer from an allergic reaction after ingestion of 6 mg (95% CI, 2-11 mg) of hazelnut protein. Objective symptoms were observed in two patients after 1 and 1,000 mg, respectively. DBPCFCs demonstrated threshold doses in half of the hazelnut-allergic patients similar to doses previously described to be hidden in consumer products. This stresses the need for careful labelling and strategies to prevent and detect contamination of food products with hazelnut residues.

Nanosecond pulse lasers for retinal applications.

PubMed

Wood, John P M; Plunkett, Malcolm; Previn, Victor; Chidlow, Glyn; Casson, Robert J

2011-08-01

Thermal lasers are routinely used to treat certain retinal disorders although they cause collateral damage to photoreceptors. The current study evaluated a confined, non-conductive thermal, 3-nanosecond pulse laser in order to determine how to produce the greatest therapeutic range without causing collateral damage. Data were compared with that obtained from a standard thermal laser. Porcine ocular explants were used; apposed neuroretina was also in place for actual laser treatment. After treatment, the retina was removed and a calcein-AM assay was used to assess retinal pigmented epithelium (RPE) cell viability in the explants. Histological methods were also employed to examine lased transverse explant sections. Three nanoseconds pulse lasers with either speckle- or gaussian-beam profile were employed in the study. Comparisons were made with a 100 milliseconds continuous wave (CW) 532 nm laser. The therapeutic energy range ratio was defined as the minimum visible effect threshold (VET) versus the minimum detectable RPE kill threshold. The 3-nanosecond lasers produced markedly lower minimum RPE kill threshold levels than the CW laser (e.g., 36 mJ/cm(2) for speckle-beam and 89 mJ/cm(2) for gaussian-beam profile nanosecond lasers vs. 7,958 mJ/cm(2) for CW laser). VET values were also correspondingly lower for the nanosecond lasers (130 mJ/cm(2) for 3 nanoseconds speckle-beam and 219 mJ/cm(2) for gaussian-beam profile vs. 1,0346 mJ/cm(2) for CW laser). Thus, the therapeutic range ratios obtained with the nanosecond lasers were much more favorable than that obtained by the CW laser: 3.6:1 for the speckle-beam and 2.5:1 for the gaussian-beam profile 3-nanosecond lasers versus 1.3:1 for the CW laser. Nanosecond lasers, particularly with a speckle-beam profile, provide a much wider therapeutic range of energies over which RPE treatment can be performed, without damage to the apposed retina, as compared with conventional CW lasers. These results may have important implications for the treatment of retinal disease. Copyright © 2011 Wiley-Liss, Inc.

INTERNATIONAL CONFERENCE ON SEMICONDUCTOR INJECTION LASERS SELCO-87: Injection lasers based on the AlGaAsSb system emitting at 1.6 μm

NASA Astrophysics Data System (ADS)

Virro, A. L.; Eliseev, P. G.; Lyuk, P. A.; Fridental, Ya K.; Khaller, Yu E.

1988-11-01

An experimental dependence of the threshold current density jth on the thickness of the active region was used to find the reduced threshold current density for AlGaAsSb (λ = 1.59μm, T = 295K) lasers: this density was 8 kA·cm-2·μm-1. The minimum threshold current was jth = 1.8 kA/cm2. Wide-contact lasers exhibited cw operation down to 175 K.

Thresholds of Transient Cavitation Produced by Pulsed Ultrasound in a Controlled Nuclei Environment.

NASA Astrophysics Data System (ADS)

Holland, Christy Katherine Smith

The possibility of hazardous bioeffects from medical ultrasound examinations and therapy, although not demonstrated in current epidemiologic data, is still of interest to the medical community. In particular, concern persists over the potential of damage at the cellular level due to transient cavitation produced by diagnostic and high intensity therapeutic ultrasound. Transient cavitation is a discrete phenomenon which relies on the existence of stabilized nuclei, or pockets of gas within a host fluid, for its genesis. A convenient descriptor for assessing the likelihood of transient cavitation is the threshold pressure, or the minimum acoustic pressure necessary to initiate bubble growth and subsequent collapse. Experimental measurements of cavitation thresholds are presented here which elucidate the importance of ultrasound host fluid and nuclei parameters in determining these thresholds. These results are interpreted in the context of an approximate theory, included as an appendix, describing the relationship between these parameters and cavitation threshold pressures. An automated experimental apparatus has been developed to determine thresholds for cavitation produced in a fluid by short tone bursts of ultrasound at 0.76, 0.99, and 2.30 MHz. A fluid jet was used to convect potential cavitation nuclei through the focal region of the insonifying transducer. Potential nuclei tested include 1mum polystyrene spheres, microbubbles in the 1-10 μm range that are stabilized with human serum albumin, and whole blood constituents. Cavitation was detected by a passive acoustical technique which is sensitive to sound scattered from cavitation bubbles. Measurements of the transient cavitation threshold in water, in a fluid of higher viscosity, and in diluted whole blood are presented. Results from these experiments which permit the control of nuclei and host fluid properties are compared to the approximate analytical theory for the prediction of the onset of cavitation.

Precipitation thresholds for triggering floods in Corgo hydrographic basin (Northern Portugal)

NASA Astrophysics Data System (ADS)

Santos, Monica; Fragoso, Marcelo

2016-04-01

The precipitation is a major cause of natural hazards and is therefore related to the flood events (Borga et al., 2011; Gaál et al., 2014; Wilhelmi & Morss, 2013). The severity of a precipitation event and their potential damage is dependent on the total amount of rain but also on the intensity and duration event (Gaál et al., 2014). In this work, it was established thresholds based on critical combinations: amount / duration of flood events with daily rainfall data for Corgo hydrographic basin, in northern Portugal. In Corgo basin are recorded 31 floods events between 1865 and 2011 (Santos et al., 2015; Zêzere et al., 2014). We determined the minimum, maximum and pre-warning thresholds that define the boundaries so that an event may occur. Additionally, we applied these thresholds to different flood events occurred in the past in the study basin. The results show that the ratio between the flood events and precipitation events that occur above the minimum threshold has relatively low probability of a flood happen. These results may be related to the reduced number of floods events (only those that caused damage reported by the media and produced some type of damage). The maximum threshold is not useful for floods forecasting, since the majority of true positives are below this limit. The retrospective analysis of the thresholds defined suggests that the minimum and pre warning thresholds are well adjusted. The application of rainfall thresholds contribute to minimize possible situations of pre-crisis or immediate crisis, reducing the consequences and the resources involved in emergency response of flood events. References Borga, M., Anagnostou, E. N., Blöschl, G., & Creutin, J. D. (2011). Flash flood forecasting, warning and risk management: the HYDRATE project. Environmental Science & Policy, 14(7), 834-844. doi: 10.1016/j.envsci.2011.05.017 Gaál, L., Molnar, P., & Szolgay, J. (2014). Selection of intense rainfall events based on intensity thresholds and lightning data in Switzerland. Hydrol. Earth Syst. Sci., 18(5), 1561-1573. doi: 10.5194/hess-18-1561-2014 Santos, M., Santos, J. A., & Fragoso, M. (2015). Historical damaging flood records for 1871-2011 in Northern Portugal and underlying atmospheric forcings. Journal of Hydrology, 530, 591-603. doi: 10.1016/j.jhydrol.2015.10.011 Wilhelmi, O. V., & Morss, R. E. (2013). Integrated analysis of societal vulnerability in an extreme precipitation event: A Fort Collins case study. Environmental Science & Policy, 26, 49-62. doi: 10.1016/j.envsci.2012.07.005 Zêzere, J. L., Pereira, S., Tavares, A. O., Bateira, C., Trigo, R. M., Quaresma, I., Santos, P. P., Santos, M., & Verde, J. (2014). DISASTER: a GIS database on hydro-geomorphologic disasters in Portugal. Nat. Hazards, 1-30. doi: 10.1007/s11069-013-1018-y

Impact of PET and MRI threshold-based tumor volume segmentation on patient-specific targeted radionuclide therapy dosimetry using CLR1404.

PubMed

Besemer, Abigail E; Titz, Benjamin; Grudzinski, Joseph J; Weichert, Jamey P; Kuo, John S; Robins, H Ian; Hall, Lance T; Bednarz, Bryan P

2017-07-06

Variations in tumor volume segmentation methods in targeted radionuclide therapy (TRT) may lead to dosimetric uncertainties. This work investigates the impact of PET and MRI threshold-based tumor segmentation on TRT dosimetry in patients with primary and metastatic brain tumors. In this study, PET/CT images of five brain cancer patients were acquired at 6, 24, and 48 h post-injection of 124 I-CLR1404. The tumor volume was segmented using two standardized uptake value (SUV) threshold levels, two tumor-to-background ratio (TBR) threshold levels, and a T1 Gadolinium-enhanced MRI threshold. The dice similarity coefficient (DSC), jaccard similarity coefficient (JSC), and overlap volume (OV) metrics were calculated to compare differences in the MRI and PET contours. The therapeutic 131 I-CLR1404 voxel-level dose distribution was calculated from the 124 I-CLR1404 activity distribution using RAPID, a Geant4 Monte Carlo internal dosimetry platform. The TBR, SUV, and MRI tumor volumes ranged from 2.3-63.9 cc, 0.1-34.7 cc, and 0.4-11.8 cc, respectively. The average  ±  standard deviation (range) was 0.19  ±  0.13 (0.01-0.51), 0.30  ±  0.17 (0.03-0.67), and 0.75  ±  0.29 (0.05-1.00) for the JSC, DSC, and OV, respectively. The DSC and JSC values were small and the OV values were large for both the MRI-SUV and MRI-TBR combinations because the regions of PET uptake were generally larger than the MRI enhancement. Notable differences in the tumor dose volume histograms were observed for each patient. The mean (standard deviation) 131 I-CLR1404 tumor doses ranged from 0.28-1.75 Gy GBq -1 (0.07-0.37 Gy GBq -1 ). The ratio of maximum-to-minimum mean doses for each patient ranged from 1.4-2.0. The tumor volume and the interpretation of the tumor dose is highly sensitive to the imaging modality, PET enhancement metric, and threshold level used for tumor volume segmentation. The large variations in tumor doses clearly demonstrate the need for standard protocols for multimodality tumor segmentation in TRT dosimetry.

Impact of PET and MRI threshold-based tumor volume segmentation on patient-specific targeted radionuclide therapy dosimetry using CLR1404

NASA Astrophysics Data System (ADS)

Besemer, Abigail E.; Titz, Benjamin; Grudzinski, Joseph J.; Weichert, Jamey P.; Kuo, John S.; Robins, H. Ian; Hall, Lance T.; Bednarz, Bryan P.

2017-08-01

Variations in tumor volume segmentation methods in targeted radionuclide therapy (TRT) may lead to dosimetric uncertainties. This work investigates the impact of PET and MRI threshold-based tumor segmentation on TRT dosimetry in patients with primary and metastatic brain tumors. In this study, PET/CT images of five brain cancer patients were acquired at 6, 24, and 48 h post-injection of 124I-CLR1404. The tumor volume was segmented using two standardized uptake value (SUV) threshold levels, two tumor-to-background ratio (TBR) threshold levels, and a T1 Gadolinium-enhanced MRI threshold. The dice similarity coefficient (DSC), jaccard similarity coefficient (JSC), and overlap volume (OV) metrics were calculated to compare differences in the MRI and PET contours. The therapeutic 131I-CLR1404 voxel-level dose distribution was calculated from the 124I-CLR1404 activity distribution using RAPID, a Geant4 Monte Carlo internal dosimetry platform. The TBR, SUV, and MRI tumor volumes ranged from 2.3-63.9 cc, 0.1-34.7 cc, and 0.4-11.8 cc, respectively. The average  ±  standard deviation (range) was 0.19  ±  0.13 (0.01-0.51), 0.30  ±  0.17 (0.03-0.67), and 0.75  ±  0.29 (0.05-1.00) for the JSC, DSC, and OV, respectively. The DSC and JSC values were small and the OV values were large for both the MRI-SUV and MRI-TBR combinations because the regions of PET uptake were generally larger than the MRI enhancement. Notable differences in the tumor dose volume histograms were observed for each patient. The mean (standard deviation) 131I-CLR1404 tumor doses ranged from 0.28-1.75 Gy GBq-1 (0.07-0.37 Gy GBq-1). The ratio of maximum-to-minimum mean doses for each patient ranged from 1.4-2.0. The tumor volume and the interpretation of the tumor dose is highly sensitive to the imaging modality, PET enhancement metric, and threshold level used for tumor volume segmentation. The large variations in tumor doses clearly demonstrate the need for standard protocols for multimodality tumor segmentation in TRT dosimetry.

Variability of space climate and its extremes with successive solar cycles

NASA Astrophysics Data System (ADS)

Chapman, Sandra; Hush, Phillip; Tindale, Elisabeth; Dunlop, Malcolm; Watkins, Nicholas

2016-04-01

Auroral geomagnetic indices coupled with in situ solar wind monitors provide a comprehensive data set, spanning several solar cycles. Space climate can be considered as the distribution of space weather. We can then characterize these observations in terms of changing space climate by quantifying how the statistical properties of ensembles of these observed variables vary between different phases of the solar cycle. We first consider the AE index burst distribution. Bursts are constructed by thresholding the AE time series; the size of a burst is the sum of the excess in the time series for each time interval over which the threshold is exceeded. The distribution of burst sizes is two component with a crossover in behaviour at thresholds ≈ 1000 nT. Above this threshold, we find[1] a range over which the mean burst size is almost constant with threshold for both solar maxima and minima. The burst size distribution of the largest events has a functional form which is exponential. The relative likelihood of these large events varies from one solar maximum and minimum to the next. If the relative overall activity of a solar maximum/minimum can be estimated, these results then constrain the likelihood of extreme events of a given size for that solar maximum/minimum. We next develop and apply a methodology to quantify how the full distribution of geomagnetic indices and upstream solar wind observables are changing between and across different solar cycles. This methodology[2] estimates how different quantiles of the distribution, or equivalently, how the return times of events of a given size, are changing. [1] Hush, P., S. C. Chapman, M. W. Dunlop, and N. W. Watkins (2015), Robust statistical properties of the size of large burst events in AE, Geophys. Res. Lett.,42 doi:10.1002/2015GL066277 [2] Chapman, S. C., D. A. Stainforth, N. W. Watkins, (2013) On estimating long term local climate trends , Phil. Trans. Royal Soc., A,371 20120287 DOI:10.1098/rsta.2012.0287

Evaluation of automated threshold selection methods for accurately sizing microscopic fluorescent cells by image analysis.

PubMed Central

Sieracki, M E; Reichenbach, S E; Webb, K L

1989-01-01

The accurate measurement of bacterial and protistan cell biomass is necessary for understanding their population and trophic dynamics in nature. Direct measurement of fluorescently stained cells is often the method of choice. The tedium of making such measurements visually on the large numbers of cells required has prompted the use of automatic image analysis for this purpose. Accurate measurements by image analysis require an accurate, reliable method of segmenting the image, that is, distinguishing the brightly fluorescing cells from a dark background. This is commonly done by visually choosing a threshold intensity value which most closely coincides with the outline of the cells as perceived by the operator. Ideally, an automated method based on the cell image characteristics should be used. Since the optical nature of edges in images of light-emitting, microscopic fluorescent objects is different from that of images generated by transmitted or reflected light, it seemed that automatic segmentation of such images may require special considerations. We tested nine automated threshold selection methods using standard fluorescent microspheres ranging in size and fluorescence intensity and fluorochrome-stained samples of cells from cultures of cyanobacteria, flagellates, and ciliates. The methods included several variations based on the maximum intensity gradient of the sphere profile (first derivative), the minimum in the second derivative of the sphere profile, the minimum of the image histogram, and the midpoint intensity. Our results indicated that thresholds determined visually and by first-derivative methods tended to overestimate the threshold, causing an underestimation of microsphere size. The method based on the minimum of the second derivative of the profile yielded the most accurate area estimates for spheres of different sizes and brightnesses and for four of the five cell types tested. A simple model of the optical properties of fluorescing objects and the video acquisition system is described which explains how the second derivative best approximates the position of the edge. Images PMID:2516431

Linking the micro and macro: L-H transition dynamics and threshold physics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Malkov, M. A., E-mail: mmalkov@ucsd.edu; Diamond, P. H.; Miki, K.

2015-03-15

The links between the microscopic dynamics and macroscopic threshold physics of the L → H transition are elucidated. Emphasis is placed on understanding the physics of power threshold scalings, and especially on understanding the minimum in the power threshold as a function of density P{sub thr} (n). By extending a numerical 1D model to evolve both electron and ion temperatures, including collisional coupling, we find that the decrease in P{sub thr} (n) along the low-density branch is due to the combination of an increase in collisional electron-to-ion energy transfer and an increase in the heating fraction coupled to the ions.more » Both processes strengthen the edge diamagnetic electric field needed to lock in the mean electric field shear for the L→H transition. The increase in P{sub thr} (n) along the high-density branch is due to the increase with ion collisionality of damping of turbulence-driven shear flows. Turbulence driven shear flows are needed to trigger the transition by extracting energy from the turbulence. Thus, we identify the critical transition physics components of the separatrix ion heat flux and the zonal flow excitation. The model reveals a power threshold minimum in density scans as a crossover between the threshold decrease supported by an increase in heat fraction received by ions (directly or indirectly, from electrons) and a threshold increase, supported by the rise in shear flow damping. The electron/ion heating mix emerges as important to the transition, in that it, together with electron-ion coupling, regulates the edge diamagnetic electric field shear. The importance of possible collisionless electron-ion heat transfer processes is explained.« less

Threshold of long-term survival of a coastal delphinid in anthropogenically degraded environment: Indo-Pacific humpback dolphins in Pearl River Delta.

PubMed

Karczmarski, Leszek; Huang, Shiang-Lin; Chan, Stephen C Y

2017-02-23

Defining demographic and ecological threshold of population persistence can assist in informing conservation management. We undertook such analyses for the Indo-Pacific humpback dolphin (Sousa chinensis) in the Pearl River Delta (PRD) region, southeast China. We use adult survival estimates for assessments of population status and annual rate of change. Our estimates indicate that, given a stationary population structure and minimal risk scenario, ~2000 individuals (minimum viable population in carrying capacity, MVP k ) can maintain the population persistence across 40 generations. However, under the current population trend (~2.5% decline/annum), the population is fast approaching its viability threshold and may soon face effects of demographic stochasticity. The population demographic trajectory and the minimum area of critical habitat (MACH) that could prevent stochastic extinction are both highly sensitive to fluctuations in adult survival. For a hypothetical stationary population, MACH should approximate 3000-km 2 . However, this estimate increases four-fold with a 5% increase of adult mortality and exceeds the size of PRD when calculated for the current population status. On the other hand, cumulatively all current MPAs within PRD fail to secure the minimum habitat requirement to accommodate sufficiently viable population size. Our findings indicate that the PRD population is deemed to become extinct unless effective conservation measures can rapidly reverse the current population trend.

D-optimal experimental designs to test for departure from additivity in a fixed-ratio mixture ray.

PubMed

Coffey, Todd; Gennings, Chris; Simmons, Jane Ellen; Herr, David W

2005-12-01

Traditional factorial designs for evaluating interactions among chemicals in a mixture may be prohibitive when the number of chemicals is large. Using a mixture of chemicals with a fixed ratio (mixture ray) results in an economical design that allows estimation of additivity or nonadditive interaction for a mixture of interest. This methodology is extended easily to a mixture with a large number of chemicals. Optimal experimental conditions can be chosen that result in increased power to detect departures from additivity. Although these designs are used widely for linear models, optimal designs for nonlinear threshold models are less well known. In the present work, the use of D-optimal designs is demonstrated for nonlinear threshold models applied to a fixed-ratio mixture ray. For a fixed sample size, this design criterion selects the experimental doses and number of subjects per dose level that result in minimum variance of the model parameters and thus increased power to detect departures from additivity. An optimal design is illustrated for a 2:1 ratio (chlorpyrifos:carbaryl) mixture experiment. For this example, and in general, the optimal designs for the nonlinear threshold model depend on prior specification of the slope and dose threshold parameters. Use of a D-optimal criterion produces experimental designs with increased power, whereas standard nonoptimal designs with equally spaced dose groups may result in low power if the active range or threshold is missed.

Clinical assessment of ossicular mobility by a ceramic vibrator designed for implantable hearing aids.

PubMed

Gyo, K; Yanagihara, N

1986-01-01

Ossicular mobility was assessed by direct coupling of a piezoelectric ceramic vibrator to the ossicles during middle ear surgery. The sites excited were body of the incus, head of the stapes, and footplate of the stapes through a hydroxyapatite ceramic strut. The threshold of the vibratory hearing was determined by the patient's response as a minimum audition, and the vibration threshold was obtained by subtracting the preoperative bone conduction threshold from the vibratory hearing threshold. The results were analyzed by the state of hearing after the operation, which revealed that a patient with a good vibration threshold during the operation had a tendency to get good postoperative hearing. This may mean that postoperative hearing can be predicted to some extent during the operation by the measurement of ossicular mobility.

Optimal glottal configuration for ease of phonation.

PubMed

Lucero, J C

1998-06-01

Recent experimental studies have shown the existence of optimal values of the glottal width and convergence angle, at which the phonation threshold pressure is minimum. These results indicate the existence of an optimal glottal configuration for ease of phonation, not predicted by the previous theory. In this paper, the origin of the optimal configuration is investigated using a low dimensional mathematical model of the vocal fold. Two phenomena of glottal aerodynamics are examined: pressure losses due to air viscosity, and air flow separation from a divergent glottis. The optimal glottal configuration seems to be a consequence of the combined effect of both factors. The results agree with the experimental data, showing that the phonation threshold pressure is minimum when the vocal folds are slightly separated in a near rectangular glottis.

Permanent fine tuning of silicon microring devices by femtosecond laser surface amorphization and ablation.

PubMed

Bachman, Daniel; Chen, Zhijiang; Fedosejevs, Robert; Tsui, Ying Y; Van, Vien

2013-05-06

We demonstrate the fine tuning capability of femtosecond laser surface modification as a permanent trimming mechanism for silicon photonic components. Silicon microring resonators with a 15 µm radius were irradiated with single 400 nm wavelength laser pulses at varying fluences. Below the laser ablation threshold, surface amorphization of the crystalline silicon waveguides yielded a tuning rate of 20 ± 2 nm/J · cm(-2)with a minimum resonance wavelength shift of 0.10nm. Above that threshold, ablation yielded a minimum resonance shift of -1.7 nm. There was some increase in waveguide loss for both trimming mechanisms. We also demonstrated the application of the method by using it to permanently correct the resonance mismatch of a second-order microring filter.

The evolution of altruism in spatial threshold public goods games via an insurance mechanism

NASA Astrophysics Data System (ADS)

Zhang, Jianlei; Zhang, Chunyan

2015-05-01

The persistence of cooperation in public goods situations has become an important puzzle for researchers. This paper considers the threshold public goods games where the option of insurance is provided for players from the standpoint of diversification of risk, envisaging the possibility of multiple strategies in such scenarios. In this setting, the provision point is defined in terms of the minimum number of contributors in one threshold public goods game, below which the game fails. In the presence of risk and insurance, more contributions are motivated if (1) only cooperators can opt to be insured and thus their contribution loss in the aborted games can be (partly or full) covered by the insurance; (2) insured cooperators obtain larger compensation, at lower values of the threshold point (the required minimum number of contributors). Moreover, results suggest the dominance of insured defectors who get a better promotion by more profitable benefits from insurance. We provide results of extensive computer simulations in the realm of spatial games (random regular networks and scale-free networks here), and support this study with analytical results for well-mixed populations. Our study is expected to establish a causal link between the widespread altruistic behaviors and the existing insurance system.

32 CFR 32.44 - Procurement procedures.

Code of Federal Regulations, 2010 CFR

2010-07-01

... acceptable characteristics or minimum acceptable standards. (iv) The specific features of “brand name or... expected to exceed the simplified acquisition threshold, specifies a “brand name” product. (4) The proposed...

Terrestrial Microgravity Model and Threshold Gravity Simulation sing Magnetic Levitation

NASA Technical Reports Server (NTRS)

Ramachandran, N.

2005-01-01

What is the threshold gravity (minimum gravity level) required for the nominal functioning of the human system? What dosage is required? Do human cell lines behave differently in microgravity in response to an external stimulus? The critical need for such a gravity simulator is emphasized by recent experiments on human epithelial cells and lymphocytes on the Space Shuttle clearly showing that cell growth and function are markedly different from those observed terrestrially. Those differences are also dramatic between cells grown in space and those in Rotating Wall Vessels (RWV), or NASA bioreactor often used to simulate microgravity, indicating that although morphological growth patterns (three dimensional growth) can be successiblly simulated using RWVs, cell function performance is not reproduced - a critical difference. If cell function is dramatically affected by gravity off-loading, then cell response to stimuli such as radiation, stress, etc. can be very different from terrestrial cell lines. Yet, we have no good gravity simulator for use in study of these phenomena. This represents a profound shortcoming for countermeasures research. We postulate that we can use magnetic levitation of cells and tissue, through the use of strong magnetic fields and field gradients, as a terrestrial microgravity model to study human cells. Specific objectives of the research are: 1. To develop a tried, tested and benchmarked terrestrial microgravity model for cell culture studies; 2. Gravity threshold determination; 3. Dosage (magnitude and duration) of g-level required for nominal functioning of cells; 4. Comparisons of magnetic levitation model to other models such as RWV, hind limb suspension, etc. and 5. Cellular response to reduced gravity levels of Moon and Mars.

Evaluation of Precipitation Detection over Various Surfaces from Passive Microwave Imagers and Sounders

NASA Technical Reports Server (NTRS)

Munchak, S. Joseph; Skofronick-Jackson, Gail

2012-01-01

During the middle part of this decade a wide variety of passive microwave imagers and sounders will be unified in the Global Precipitation Measurement (GPM) mission to provide a common basis for frequent (3 hr), global precipitation monitoring. The ability of these sensors to detect precipitation by discerning it from non-precipitating background depends upon the channels available and characteristics of the surface and atmosphere. This study quantifies the minimum detectable precipitation rate and fraction of precipitation detected for four representative instruments (TMI, GMI, AMSU-A, and AMSU-B) that will be part of the GPM constellation. Observations for these instruments were constructed from equivalent channels on the SSMIS instrument on DMSP satellites F16 and F17 and matched to precipitation data from NOAA's National Mosaic and QPE (NMQ) during 2009 over the continuous United States. A variational optimal estimation retrieval of non-precipitation surface and atmosphere parameters was used to determine the consistency between the observed brightness temperatures and these parameters, with high cost function values shown to be related to precipitation. The minimum detectable precipitation rate, defined as the lowest rate for which probability of detection exceeds 50%, and the detected fraction of precipitation, are reported for each sensor, surface type (ocean, coast, bare land, snow cover) and precipitation type (rain, mix, snow). The best sensors over ocean and bare land were GMI (0.22 mm/hr minimum threshold and 90% of precipitation detected) and AMSU (0.26 mm/hr minimum threshold and 81% of precipitation detected), respectively. Over coasts (0.74 mm/hr threshold and 12% detected) and snow-covered surfaces (0.44 mm/hr threshold and 23% detected), AMSU again performed best but with much lower detection skill, whereas TMI had no skill over these surfaces. The sounders (particularly over water) benefited from the use of re-analysis data (vs. climatology) to set the a-priori atmospheric state and all instruments benefit from the use of a conditional snow cover emissivity database over land. It is recommended that real-time sources of these data be used in the operational GPM precipitation algorithms.

Chromosomal Expression of the Haemophilus influenzae Hap Autotransporter Allows Fine-Tuned Regulation of Adhesive Potential via Inhibition of Intermolecular Autoproteolysis

PubMed Central

Fink, Doran L.; St. Geme III, Joseph W.

2003-01-01

The Haemophilus influenzae Hap autotransporter is a nonpilus adhesin that promotes adherence to respiratory epithelial cells and selected extracellular matrix proteins and facilitates bacterial aggregation and microcolony formation. Hap consists of a 45-kDa outer membrane translocator domain called Hapβ and a 110-kDa extracellular passenger domain called HapS. All adhesive activity resides within HapS, which also contains protease activity and directs its own secretion from the bacterial cell surface via intermolecular autoproteolysis. In the present study, we sought to determine the relationship between the magnitude of Hap expression, the efficiency of Hap autoproteolysis, and the level of Hap-mediated adherence and aggregation. We found that a minimum threshold of Hap precursor was required for autoproteolysis and that this threshold approximated expression of Hap from a chromosomal allele, as occurs in H. influenzae clinical isolates. Chromosomal expression of wild-type Hap was sufficient to promote significant adherence to epithelial cells and extracellular matrix proteins, and adherence was enhanced substantially by inhibition of autoproteolysis. In contrast, chromosomal expression of Hap was sufficient to promote bacterial aggregation only when autoproteolysis was inhibited, indicating that the threshold for Hap-mediated aggregation is above the threshold for autoproteolysis. These results highlight the critical role of autoproteolysis and an intermolecular mechanism of cleavage in controlling the diverse adhesive activities of Hap. PMID:12591878

Statistical mechanical analysis of linear programming relaxation for combinatorial optimization problems

NASA Astrophysics Data System (ADS)

Takabe, Satoshi; Hukushima, Koji

2016-05-01

Typical behavior of the linear programming (LP) problem is studied as a relaxation of the minimum vertex cover (min-VC), a type of integer programming (IP) problem. A lattice-gas model on the Erdös-Rényi random graphs of α -uniform hyperedges is proposed to express both the LP and IP problems of the min-VC in the common statistical mechanical model with a one-parameter family. Statistical mechanical analyses reveal for α =2 that the LP optimal solution is typically equal to that given by the IP below the critical average degree c =e in the thermodynamic limit. The critical threshold for good accuracy of the relaxation extends the mathematical result c =1 and coincides with the replica symmetry-breaking threshold of the IP. The LP relaxation for the minimum hitting sets with α ≥3 , minimum vertex covers on α -uniform random graphs, is also studied. Analytic and numerical results strongly suggest that the LP relaxation fails to estimate optimal values above the critical average degree c =e /(α -1 ) where the replica symmetry is broken.

Statistical mechanical analysis of linear programming relaxation for combinatorial optimization problems.

PubMed

Takabe, Satoshi; Hukushima, Koji

2016-05-01

Typical behavior of the linear programming (LP) problem is studied as a relaxation of the minimum vertex cover (min-VC), a type of integer programming (IP) problem. A lattice-gas model on the Erdös-Rényi random graphs of α-uniform hyperedges is proposed to express both the LP and IP problems of the min-VC in the common statistical mechanical model with a one-parameter family. Statistical mechanical analyses reveal for α=2 that the LP optimal solution is typically equal to that given by the IP below the critical average degree c=e in the thermodynamic limit. The critical threshold for good accuracy of the relaxation extends the mathematical result c=1 and coincides with the replica symmetry-breaking threshold of the IP. The LP relaxation for the minimum hitting sets with α≥3, minimum vertex covers on α-uniform random graphs, is also studied. Analytic and numerical results strongly suggest that the LP relaxation fails to estimate optimal values above the critical average degree c=e/(α-1) where the replica symmetry is broken.

Quantifying 10 years of Improvements in Earthquake and Tsunami Monitoring in the Caribbean and Adjacent Regions

NASA Astrophysics Data System (ADS)

von Hillebrandt-Andrade, C.; Huerfano Moreno, V. A.; McNamara, D. E.; Saurel, J. M.

2014-12-01

The magnitude-9.3 Sumatra-Andaman Islands earthquake of December 26, 2004, increased global awareness to the destructive hazard of earthquakes and tsunamis. Post event assessments of global coastline vulnerability highlighted the Caribbean as a region of high hazard and risk and that it was poorly monitored. Nearly 100 tsunamis have been reported for the Caribbean region and Adjacent Regions in the past 500 years and continue to pose a threat for its nations, coastal areas along the Gulf of Mexico, and the Atlantic seaboard of North and South America. Significant efforts to improve monitoring capabilities have been undertaken since this time including an expansion of the United States Geological Survey (USGS) Global Seismographic Network (GSN) (McNamara et al., 2006) and establishment of the United Nations Educational, Scientific and Cultural Organization (UNESCO) Intergovernmental Coordination Group (ICG) for the Tsunami and other Coastal Hazards Warning System for the Caribbean and Adjacent Regions (CARIBE EWS). The minimum performance standards it recommended for initial earthquake locations include: 1) Earthquake detection within 1 minute, 2) Minimum magnitude threshold = M4.5, and 3) Initial hypocenter error of <30 km. In this study, we assess current compliance with performance standards and model improvements in earthquake and tsunami monitoring capabilities in the Caribbean region since the first meeting of the UNESCO ICG-Caribe EWS in 2006. The three measures of network capability modeled in this study are: 1) minimum Mw detection threshold; 2) P-wave detection time of an automatic processing system and; 3) theoretical earthquake location uncertainty. By modeling three measures of seismic network capability, we can optimize the distribution of ICG-Caribe EWS seismic stations and select an international network that will be contributed from existing real-time broadband national networks in the region. Sea level monitoring improvements both offshore and along the coast will also be addressed. With the support of Member States and other countries and organizations it has been possible to significantly expand the sea level network thus reducing the amount of time it now takes to verify tsunamis.

Auditory sensitivity of larval zebrafish (Danio rerio) measured using a behavioral prepulse inhibition assay

PubMed Central

Bhandiwad, Ashwin A.; Zeddies, David G.; Raible, David W.; Rubel, Edwin W.; Sisneros, Joseph A.

2013-01-01

SUMMARY Zebrafish (Danio rerio) have become a valuable model for investigating the molecular genetics and development of the inner ear in vertebrates. In this study, we employed a prepulse inhibition (PPI) paradigm to assess hearing in larval wild-type (AB) zebrafish during early development at 5–6 days post-fertilization (d.p.f.). We measured the PPI of the acoustic startle response in zebrafish using a 1-dimensional shaker that simulated the particle motion component of sound along the fish's dorsoventral axis. The thresholds to startle-inducing stimuli were determined in 5–6 d.p.f. zebrafish, and their hearing sensitivity was then characterized using the thresholds of prepulse tone stimuli (90–1200 Hz) that inhibited the acoustic startle response to a reliable startle stimulus (820 Hz at 20 dB re. 1 m s−2). Hearing thresholds were defined as the minimum prepulse tone level required to significantly reduce the startle response probability compared with the baseline (no-prepulse) condition. Larval zebrafish showed greatest auditory sensitivity from 90 to 310 Hz with corresponding mean thresholds of −19 to −10 dB re. 1 m s−2, respectively. Hearing thresholds of prepulse tones were considerably lower than previously predicted by startle response assays. The PPI assay was also used to investigate the relative contribution of the lateral line to the detection of acoustic stimuli. After aminoglycoside-induced neuromast hair-cell ablation, we found no difference in PPI thresholds between treated and control fish. We propose that this PPI assay can be used to screen for novel zebrafish hearing mutants and to investigate the ontogeny of hearing in zebrafish and other fishes. PMID:23966590

An Evaluation of Performance Thresholds in Nursing Home Pay-for-Performance.

PubMed

Werner, Rachel M; Skira, Meghan; Konetzka, R Tamara

2016-12-01

Performance thresholds are commonly used in pay-for-performance (P4P) incentives, where providers receive a bonus payment for achieving a prespecified target threshold but may produce discontinuous incentives, with providers just below the threshold having the strongest incentive to improve and providers either far below or above the threshold having little incentive. We investigate the effect of performance thresholds on provider response in the setting of nursing home P4P. The Minimum Data Set (MDS) and Online Survey, Certification, and Reporting (OSCAR) datasets. Difference-in-differences design to test for changes in nursing home performance in three states that implemented threshold-based P4P (Colorado, Georgia, and Oklahoma) versus three comparator states (Arizona, Tennessee, and Arkansas) between 2006 and 2009. We find that those farthest below the threshold (i.e., the worst-performing nursing homes) had the largest improvements under threshold-based P4P while those farthest above the threshold worsened. This effect did not vary with the percentage of Medicaid residents in a nursing home. Threshold-based P4P may provide perverse incentives for nursing homes above the performance threshold, but we do not find evidence to support concerns about the effects of performance thresholds on low-performing nursing homes. © Health Research and Educational Trust.

40 CFR 30.44 - Procurement procedures.

Code of Federal Regulations, 2010 CFR

2010-07-01

... characteristics or minimum acceptable standards. (iv) The specific features of “brand name or equal” descriptions..., specifies a “brand name” product. (4) The proposed award over the small purchase threshold is to be awarded...

Generalized minimum dominating set and application in automatic text summarization

NASA Astrophysics Data System (ADS)

Xu, Yi-Zhi; Zhou, Hai-Jun

2016-03-01

For a graph formed by vertices and weighted edges, a generalized minimum dominating set (MDS) is a vertex set of smallest cardinality such that the summed weight of edges from each outside vertex to vertices in this set is equal to or larger than certain threshold value. This generalized MDS problem reduces to the conventional MDS problem in the limiting case of all the edge weights being equal to the threshold value. We treat the generalized MDS problem in the present paper by a replica-symmetric spin glass theory and derive a set of belief-propagation equations. As a practical application we consider the problem of extracting a set of sentences that best summarize a given input text document. We carry out a preliminary test of the statistical physics-inspired method to this automatic text summarization problem.

When do Indians feel hot? Internet searches indicate seasonality suppresses adaptation to heat

NASA Astrophysics Data System (ADS)

Singh, Tanya; Siderius, Christian; Van der Velde, Ype

2018-05-01

In a warming world an increasing number of people are being exposed to heat, making a comfortable thermal environment an important need. This study explores the potential of using Regional Internet Search Frequencies (RISF) for air conditioning devices as an indicator for thermal discomfort (i.e. dissatisfaction with the thermal environment) with the aim to quantify the adaptation potential of individuals living across different climate zones and at the high end of the temperature range, in India, where access to health data is limited. We related RISF for the years 2011–2015 to daily daytime outdoor temperature in 17 states and determined at which temperature RISF for air conditioning starts to peak, i.e. crosses a ‘heat threshold’, in each state. Using the spatial variation in heat thresholds, we explored whether people continuously exposed to higher temperatures show a lower response to heat extremes through adaptation (e.g. physiological, behavioural or psychological). State-level heat thresholds ranged from 25.9 °C in Madhya Pradesh to 31.0 °C in Orissa. Local adaptation was found to occur at state level: the higher the average temperature in a state, the higher the heat threshold; and the higher the intra-annual temperature range (warmest minus coldest month) the lower the heat threshold. These results indicate there is potential within India to adapt to warmer temperatures, but that a large intra-annual temperature variability attenuates this potential to adapt to extreme heat. This winter ‘reset’ mechanism should be taken into account when assessing the impact of global warming, with changes in minimum temperatures being an important factor in addition to the change in maximum temperatures itself. Our findings contribute to a better understanding of local heat thresholds and people’s adaptive capacity, which can support the design of local thermal comfort standards and early heat warning systems.

Earth Observing System Covariance Realism

NASA Technical Reports Server (NTRS)

Zaidi, Waqar H.; Hejduk, Matthew D.

2016-01-01

The purpose of covariance realism is to properly size a primary object's covariance in order to add validity to the calculation of the probability of collision. The covariance realism technique in this paper consists of three parts: collection/calculation of definitive state estimates through orbit determination, calculation of covariance realism test statistics at each covariance propagation point, and proper assessment of those test statistics. An empirical cumulative distribution function (ECDF) Goodness-of-Fit (GOF) method is employed to determine if a covariance is properly sized by comparing the empirical distribution of Mahalanobis distance calculations to the hypothesized parent 3-DoF chi-squared distribution. To realistically size a covariance for collision probability calculations, this study uses a state noise compensation algorithm that adds process noise to the definitive epoch covariance to account for uncertainty in the force model. Process noise is added until the GOF tests pass a group significance level threshold. The results of this study indicate that when outliers attributed to persistently high or extreme levels of solar activity are removed, the aforementioned covariance realism compensation method produces a tuned covariance with up to 80 to 90% of the covariance propagation timespan passing (against a 60% minimum passing threshold) the GOF tests-a quite satisfactory and useful result.

High-Fidelity Quantum Logic Gates Using Trapped-Ion Hyperfine Qubits.

PubMed

Ballance, C J; Harty, T P; Linke, N M; Sepiol, M A; Lucas, D M

2016-08-05

We demonstrate laser-driven two-qubit and single-qubit logic gates with respective fidelities 99.9(1)% and 99.9934(3)%, significantly above the ≈99% minimum threshold level required for fault-tolerant quantum computation, using qubits stored in hyperfine ground states of calcium-43 ions held in a room-temperature trap. We study the speed-fidelity trade-off for the two-qubit gate, for gate times between 3.8  μs and 520  μs, and develop a theoretical error model which is consistent with the data and which allows us to identify the principal technical sources of infidelity.

Two-stage magnetic orientation of uric acid crystals as gout initiators

NASA Astrophysics Data System (ADS)

Takeuchi, Y.; Miyashita, Y.; Mizukawa, Y.; Iwasaka, M.

2014-01-01

The present study focuses on the magnetic behavior of uric acid crystals, which are responsible for gout. Under a sub-Tesla (T)-level magnetic field, rotational motion of the crystals, which were caused by diamagnetic torque, was observed. We used horizontal magnetic fields with a maximum magnitude of 500 mT generated by an electromagnet to observe the magnetic orientation of the uric acid microcrystals by a microscope. The uric acid crystals showed a perpendicular magnetic field orientation with a minimum threshold of 130 mT. We speculate that the distinct diamagnetic anisotropy in the uric acid crystals resulted in their rotational responses.

Evaluation of viral load thresholds for predicting new WHO Stage 3 and 4 events in HIV-infected children receiving highly active antiretroviral therapy

PubMed Central

Siberry, George K; Harris, D. Robert; Oliveira, Ricardo Hugo; Krauss, Margot R.; Hofer, Cristina B.; Tiraboschi, Adriana Aparecida; Marques, Heloisa; Succi, Regina C.; Abreu, Thalita; Negra, Marinella Della; Mofenson, Lynne M.; Hazra, Rohan

2012-01-01

Background This study evaluated a wide range of viral load (VL) thresholds to identify a cut-point that best predicts new clinical events in children on stable highly-active antiretroviral therapy (HAART). Methods Cox proportional hazards modeling was used to assess the adjusted risk of World Health Organization stage 3 or 4 clinical events (WHO events) as a function of time-varying CD4, VL, and hemoglobin values in a cohort study of Latin American children on HAART ≥ 6 months. Models were fit using different VL cut-points between 400 and 50,000 copies/mL, with model fit evaluated on the basis of the minimum Akaike Information Criterion (AIC) value, a standard model fit statistic. Results Models were based on 67 subjects with WHO events out of 550 subjects on study. The VL cutpoints of > 2600 copies/mL and > 32,000 copies/mL corresponded to the lowest AIC values and were associated with the highest hazard ratios [2.0 (p = 0.015) and 2.1 (p = 0.0058), respectively] for WHO events. Conclusions In HIV-infected Latin American children on stable HAART, two distinct VL thresholds (> 2,600 copies/mL and > 32,000 copies/mL) were identified for predicting children at significantly increased risk of HIV-related clinical illness, after accounting for CD4 level, hemoglobin level, and other significant factors. PMID:22343177

The Gap Detection Test: Can It Be Used to Diagnose Tinnitus?

PubMed

Boyen, Kris; Başkent, Deniz; van Dijk, Pim

2015-01-01

Animals with induced tinnitus showed difficulties in detecting silent gaps in sounds, suggesting that the tinnitus percept may be filling the gap. The main purpose of this study was to evaluate the applicability of this approach to detect tinnitus in human patients. The authors first hypothesized that gap detection would be impaired in patients with tinnitus, and second, that gap detection would be more impaired at frequencies close to the tinnitus frequency of the patient. Twenty-two adults with bilateral tinnitus, 20 age-matched and hearing loss-matched subjects without tinnitus, and 10 young normal-hearing subjects participated in the study. To determine the characteristics of the tinnitus, subjects matched an external sound to their perceived tinnitus in pitch and loudness. To determine the minimum detectable gap, the gap threshold, an adaptive psychoacoustic test was performed three times by each subject. In this gap detection test, four different stimuli, with various frequencies and bandwidths, were presented at three intensity levels each. Similar to previous reports of gap detection, increasing sensation level yielded shorter gap thresholds for all stimuli in all groups. Interestingly, the tinnitus group did not display elevated gap thresholds in any of the four stimuli. Moreover, visual inspection of the data revealed no relation between gap detection performance and perceived tinnitus pitch. These findings show that tinnitus in humans has no effect on the ability to detect gaps in auditory stimuli. Thus, the testing procedure in its present form is not suitable for clinical detection of tinnitus in humans.

Influence of two-electrode montages on the level-specific (LS) CE-Chirp auditory brainstem response (ABR) at multiple intensity levels.

PubMed

Dzulkarnain, Ahmad Aidil Arafat; Noor Ibrahim, Siti Hajra Mu'minah; Anuar, Nur Farah Aida; Abdullah, Siti Aisyah; Tengku Zam Zam, Tengku Zulaila Hasma; Rahmat, Sarah; Mohd Ruzai, Muhammad Amar

2017-10-01

To investigate the influence of two different electrode montages (ipsilateral: reference to mastoid and vertical: reference to nape of neck) to the ABR results recorded using a level-specific (LS)-CE-Chirp® in normally hearing subjects at multiple intensities levels. Quasi-experimental and repeated measure study designs were applied in this study. Two different stopping criteria were used, (1) a fixed-signal averaging 4000 sweeps and, (2) a minimum quality indicator of Fmp = 3.1 with a minimum of 800 sweeps. Twenty-nine normally hearing adults (18 females, 11 male) participated. Wave V amplitudes were significantly larger in the LS CE-Chirp® recorded from the vertical montage than the ipsilateral montage. Waves I and III amplitudes were significantly larger from the ipsilateral LS CE-Chirp® than from the other montages and stimulus combinations. The differences in the quality of the ABR recording between the vertical and ipsilateral montages were marginal. Overall, the result suggested that the vertical LS CE-Chirp® ABR had a high potential for a threshold-seeking application, because it produced a higher wave V amplitude. The Ipsilateral LS CE-Chirp® ABR, on the other hand, might also have a high potential for the site of lesion application, because it produced larger waves I and III amplitudes.

The Effect of Introducing a Minimum Price on the Distribution of Alcohol Purchase: A Counterfactual Analysis.

PubMed

Sharma, Anurag; Etilé, Fabrice; Sinha, Kompal

2016-09-01

We use counterfactual analysis techniques to evaluate the impact of a $2 minimum unit price (MUP) on the distribution of Australian (Victorian) household off-trade alcohol purchases. Our estimates suggest that a $2 MUP significantly reduces the purchases of at-risk households by up to -0.92 [90% CI: -1.55, -0.28] standard drinks at the highest quantiles and has substantially less effect on households purchasing at light and moderate levels. A $2 MUP may reduce the proportions of male and female shoppers purchasing at the public health threshold of more than two standard drinks per household member per day by -3.03 [90% CI: -4.83, -1.22] percentage points (relative variation: -17%); and -1.85 [90% CI: -2.60, -1.10] percentage points (relative variation:-22%), respectively. Implementing an MUP on alcohol thus promises significant positive impacts on public health. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Extreme value theory applied to the definition of bathing water quality discounting limits.

PubMed

Haggarty, R A; Ferguson, C A; Scott, E M; Iroegbu, C; Stidson, R

2010-02-01

The European Community Bathing Water Directive (European Parliament, 2006) set compliance standards for bathing waters across Europe, with minimum standards for microbiological indicators to be attained at all locations by 2015. The Directive allows up to 15% of samples affected by short-term pollution episodes to be disregarded from the figures used to classify bathing waters, provided certain management criteria have been met, including informing the public of short-term water pollution episodes. Therefore, a scientifically justifiable discounting limit is required which could be used as a management tool to determine the samples that should be removed. This paper investigates different methods of obtaining discounting limits, focusing in particular on extreme value methodology applied to data from Scottish bathing waters. Return level based limits derived from threshold models applied at a site-specific level improved the percentage of sites which met at least the minimum required standard. This approach provides a method of obtaining limits which identify the samples that should be removed from compliance calculations, although care has to be taken in terms of the quantity of data which is removed. (c) 2009 Elsevier Ltd. All rights reserved.

Convolving optically addressed VLSI liquid crystal SLM

NASA Astrophysics Data System (ADS)

Jared, David A.; Stirk, Charles W.

1994-03-01

We designed, fabricated, and tested an optically addressed spatial light modulator (SLM) that performs a 3 X 3 kernel image convolution using ferroelectric liquid crystal on VLSI technology. The chip contains a 16 X 16 array of current-mirror-based convolvers with a fixed kernel for finding edges. The pixels are located on 75 micron centers, and the modulators are 20 microns on a side. The array successfully enhanced edges in illumination patterns. We developed a high-level simulation tool (CON) for analyzing the performance of convolving SLM designs. CON has a graphical interface and simulates SLM functions using SPICE-like device models. The user specifies the pixel function along with the device parameters and nonuniformities. We discovered through analysis, simulation and experiment that the operation of current-mirror-based convolver pixels is degraded at low light levels by the variation of transistor threshold voltages inherent to CMOS chips. To function acceptable, the test SLM required the input image to have an minimum irradiance of 10 (mu) W/cm2. The minimum required irradiance can be further reduced by adding a photodarlington near the photodetector or by increasing the size of the transistors used to calculate the convolution.

Study of multipactor suppression of microwave components using perforated waveguide technology for space applications

NASA Astrophysics Data System (ADS)

Ye, Ming; Li, Yun; He, Yongning; Daneshmand, Mojgan

2017-05-01

With the development of space technology, microwave components with increased power handling capability and reduced weight have been urgently required. In this work, the perforated waveguide technology is proposed to suppress the multipactor effect of high power microwave components. Meanwhile, this novel method has the advantage of reducing components' weight, which makes it to have great potential in space applications. The perforated part of the waveguide components can be seen as an electron absorber (namely, its total electron emission yield is zero) since most of the electrons impacting on this part will go out of the components. Based on thoroughly benchmarked numerical simulation procedures, we simulated an S band and an X band waveguide transformer to conceptually verify this idea. Both electron dynamic simulations and electrical loss simulations demonstrate that the perforation technology can improve the multipactor threshold at least ˜8 dB while maintaining the acceptable insertion loss level compared with its un-perforated components. We also found that the component with larger minimum gap is easier to achieve multipactor suppression. This effect is interpreted by a parallel plate waveguide model. What's more, to improve the multipactor threshold of the X band waveguide transformer with a minimum gap of ˜0.1 mm, we proposed a perforation structure with the slope edge and explained its mechanism. Future study will focus on further optimization of the perforation structure, size, and distribution to maximize the comprehensive performances of microwave components.

Navy Pier roundabout, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation during the excavation process did not exceed theinstrument threshold previously stated, and ranged from a minimum of 2,300 cpm to a maximum of 4,300cpm unshielded.

305 E. Erie Street, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation during the excavation process did not exceed theinstrument threshold previously stated, and ranged from a minimum of 1,900 cpm to a maximum of 3,900cpm unshielded.

215 E. Grand Ave, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation during the excavation process did not exceed theinstrument threshold previously stated, and ranged from a minimum of 1,300 cpm to a maximum of 3,500cpm shielded.

A novel gene network inference algorithm using predictive minimum description length approach.

PubMed

Chaitankar, Vijender; Ghosh, Preetam; Perkins, Edward J; Gong, Ping; Deng, Youping; Zhang, Chaoyang

2010-05-28

Reverse engineering of gene regulatory networks using information theory models has received much attention due to its simplicity, low computational cost, and capability of inferring large networks. One of the major problems with information theory models is to determine the threshold which defines the regulatory relationships between genes. The minimum description length (MDL) principle has been implemented to overcome this problem. The description length of the MDL principle is the sum of model length and data encoding length. A user-specified fine tuning parameter is used as control mechanism between model and data encoding, but it is difficult to find the optimal parameter. In this work, we proposed a new inference algorithm which incorporated mutual information (MI), conditional mutual information (CMI) and predictive minimum description length (PMDL) principle to infer gene regulatory networks from DNA microarray data. In this algorithm, the information theoretic quantities MI and CMI determine the regulatory relationships between genes and the PMDL principle method attempts to determine the best MI threshold without the need of a user-specified fine tuning parameter. The performance of the proposed algorithm was evaluated using both synthetic time series data sets and a biological time series data set for the yeast Saccharomyces cerevisiae. The benchmark quantities precision and recall were used as performance measures. The results show that the proposed algorithm produced less false edges and significantly improved the precision, as compared to the existing algorithm. For further analysis the performance of the algorithms was observed over different sizes of data. We have proposed a new algorithm that implements the PMDL principle for inferring gene regulatory networks from time series DNA microarray data that eliminates the need of a fine tuning parameter. The evaluation results obtained from both synthetic and actual biological data sets show that the PMDL principle is effective in determining the MI threshold and the developed algorithm improves precision of gene regulatory network inference. Based on the sensitivity analysis of all tested cases, an optimal CMI threshold value has been identified. Finally it was observed that the performance of the algorithms saturates at a certain threshold of data size.

Optimization strategies with resource scarcity: From immunization of networks to the traveling salesman problem

NASA Astrophysics Data System (ADS)

Bellingeri, Michele; Agliari, Elena; Cassi, Davide

2015-10-01

The best strategy to immunize a complex network is usually evaluated in terms of the percolation threshold, i.e. the number of vaccine doses which make the largest connected cluster (LCC) vanish. The strategy inducing the minimum percolation threshold represents the optimal way to immunize the network. Here we show that the efficacy of the immunization strategies can change during the immunization process. This means that, if the number of doses is limited, the best strategy is not necessarily the one leading to the smallest percolation threshold. This outcome should warn about the adoption of global measures in order to evaluate the best immunization strategy.

The Threshold Shortest Path Interdiction Problem for Critical Infrastructure Resilience Analysis

DTIC Science & Technology

2017-09-01

being pushed over the minimum designated threshold. 1.4 Motivation A simple setting to motivate this research is the “30 minutes or it’s free” guarantee...parallel network structure in Fig. 4.4 is simple in design , yet shows a relatively high resilience when compared to the other networks in general. The high...United States Naval Academy, 2002 Submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE IN OPERATIONS RESEARCH

Objective lens simultaneously optimized for pupil ghosting, wavefront delivery and pupil imaging

NASA Technical Reports Server (NTRS)

Olczak, Eugene G (Inventor)

2011-01-01

An objective lens includes multiple optical elements disposed between a first end and a second end, each optical element oriented along an optical axis. Each optical surface of the multiple optical elements provides an angle of incidence to a marginal ray that is above a minimum threshold angle. This threshold angle minimizes pupil ghosts that may enter an interferometer. The objective lens also optimizes wavefront delivery and pupil imaging onto an optical surface under test.

A wavelet-based adaptive fusion algorithm of infrared polarization imaging

NASA Astrophysics Data System (ADS)

Yang, Wei; Gu, Guohua; Chen, Qian; Zeng, Haifang

2011-08-01

The purpose of infrared polarization image is to highlight man-made target from a complex natural background. For the infrared polarization images can significantly distinguish target from background with different features, this paper presents a wavelet-based infrared polarization image fusion algorithm. The method is mainly for image processing of high-frequency signal portion, as for the low frequency signal, the original weighted average method has been applied. High-frequency part is processed as follows: first, the source image of the high frequency information has been extracted by way of wavelet transform, then signal strength of 3*3 window area has been calculated, making the regional signal intensity ration of source image as a matching measurement. Extraction method and decision mode of the details are determined by the decision making module. Image fusion effect is closely related to the setting threshold of decision making module. Compared to the commonly used experiment way, quadratic interpolation optimization algorithm is proposed in this paper to obtain threshold. Set the endpoints and midpoint of the threshold searching interval as initial interpolation nodes, and compute the minimum quadratic interpolation function. The best threshold can be obtained by comparing the minimum quadratic interpolation function. A series of image quality evaluation results show this method has got improvement in fusion effect; moreover, it is not only effective for some individual image, but also for a large number of images.

301-15 East Illinois St, December 2017, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation during the excavation process did not exceed theinstrument threshold previously stated, and ranged from a minimum of 800 cpm to a maximum of 2,800cpm shielded.

335 E. Erie, January 2016, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation during the excavation process did not exceed theinstrument threshold previously stated and ranged from a minimum of 4,900 cpm to a maximum of 10,200cpm unshielded.

215 E. Grand Ave, December 2015, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation during the excavation process did not exceed theinstrument threshold previously stated and ranged from a minimum of 6,800 cpm to a maximum of 7,200cpm unshielded.

243 E. Ontario Street - Water, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation during the excavation process did not exceed theinstrument threshold previously stated, and ranged from a minimum of 1,400 cpm to a maximum of 2,600cpm shielded.

224 E Ontario, February 2015, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation during the excavation process did not exceed theinstrument threshold previously stated and ranged from a minimum of 6,200 cpm to a maximum of 7,500cpm unshielded.

54-63 East Ohio St., Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation during the excavation process did not exceed theinstrument threshold previously stated, and ranged from a minimum of 2,000 cpm to a maximum of 2,300cpm shielded.

225 E. Grand Ave, Septmber 2015, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation during the excavation process did not exceed theinstrument threshold previously stated and ranged from a minimum of 5,300 cpm to a maximum of 9,700cpm unshielded.

243 E. Ontario Street - Sewer, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation during the excavation process did not exceed theinstrument threshold previously stated, and ranged from a minimum of 1,100 cpm to a maximum of 3,600cpm shielded.

226-237 E. Ontario, April 2016, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

Field gamma measurements did not exceed the field instrument threshold equivalent to the USEPA removal actionlevel and ranged from a minimum of 6,000 cpm to a maximum of approximately 9,000 cpm unshielded.

228 E. Ontario, February 2016, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation during the excavation process did not exceed theinstrument threshold previously stated and ranged from a minimum of 5,400 cpm to a maximum of 10,000cpm unshielded.

330-334 E. Ontario, April 2016, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

Field gamma measurement did not exceed the field instrument threshold equivalent to the USEPA removal actionlevel and ranged from a minimum of 5,700 cpm to a maximum of approximately 13,100 cpm unshielded.

Partial photoionization cross sections of NH4 and H3O Rydberg radicals

NASA Astrophysics Data System (ADS)

Velasco, A. M.; Lavín, C.; Martín, I.; Melin, J.; Ortiz, J. V.

2009-07-01

Photoionization cross sections for various Rydberg series that correspond to ionization channels of ammonium and oxonium Rydberg radicals from the outermost, occupied orbitals of their respective ground states are reported. These properties are known to be relevant in photoelectron dynamics studies. For the present calculations, the molecular-adapted quantum defect orbital method has been employed. A Cooper minimum has been found in the 3sa1-kpt2 Rydberg channel of NH4 beyond the ionization threshold, which provides the main contribution to the photoionization of this radical. However, no net minimum is found in the partial cross section of H3O despite the presence of minima in the 3sa1-kpe and 3sa1-kpa1 Rydberg channels. The complete oscillator strength distributions spanning the discrete and continuous regions of both radicals exhibit the expected continuity across the ionization threshold.

Metastable Features of Economic Networks and Responses to Exogenous Shocks

PubMed Central

Hosseiny, Ali; Bahrami, Mohammad; Palestrini, Antonio; Gallegati, Mauro

2016-01-01

It is well known that a network structure plays an important role in addressing a collective behavior. In this paper we study a network of firms and corporations for addressing metastable features in an Ising based model. In our model we observe that if in a recession the government imposes a demand shock to stimulate the network, metastable features shape its response. Actually we find that there exists a minimum bound where any demand shock with a size below it is unable to trigger the market out of recession. We then investigate the impact of network characteristics on this minimum bound. We surprisingly observe that in a Watts-Strogatz network, although the minimum bound depends on the average of the degrees, when translated into the language of economics, such a bound is independent of the average degrees. This bound is about 0.44ΔGDP, where ΔGDP is the gap of GDP between recession and expansion. We examine our suggestions for the cases of the United States and the European Union in the recent recession, and compare them with the imposed stimulations. While the stimulation in the US has been above our threshold, in the EU it has been far below our threshold. Beside providing a minimum bound for a successful stimulation, our study on the metastable features suggests that in the time of crisis there is a “golden time passage” in which the minimum bound for successful stimulation can be much lower. Hence, our study strongly suggests stimulations to arise within this time passage. PMID:27706166

Higher Accuracy of the Lactate Minimum Test Compared to Established Threshold Concepts to Determine Maximal Lactate Steady State in Running.

PubMed

Wahl, Patrick; Zwingmann, Lukas; Manunzio, Christian; Wolf, Jacob; Bloch, Wilhelm

2018-05-18

This study evaluated the accuracy of the lactate minimum test, in comparison to a graded-exercise test and established threshold concepts (OBLA and mDmax) to determine running speed at maximal lactate steady state. Eighteen subjects performed a lactate minimum test, a graded-exercise test (2.4 m·s -1 start,+0.4 m·s -1 every 5 min) and 2 or more constant-speed tests of 30 min to determine running speed at maximal lactate steady state. The lactate minimum test consisted of an initial lactate priming segment, followed by a short recovery phase. Afterwards, the initial load of the subsequent incremental segment was individually determined and was increased by 0.1 m·s -1 every 120 s. Lactate minimum was determined by the lowest measured value (LM abs ) and by a third-order polynomial (LM pol ). The mean difference to maximal lactate steady state was+0.01±0.14 m·s -1 (LM abs ), 0.04±0.15 m·s -1 (LM pol ), -0.06±0.31 m·s 1 (OBLA) and -0.08±0.21 m·s 1 (mDmax). The intraclass correlation coefficient (ICC) between running velocity at maximal lactate steady state and LM abs was highest (ICC=0.964), followed by LM pol (ICC=0.956), mDmax (ICC=0.916) and OBLA (ICC=0.885). Due to the higher accuracy of the lactate minimum test to determine maximal lactate steady state compared to OBLA and mDmax, we suggest the lactate minimum test as a valid and meaningful concept to estimate running velocity at maximal lactate steady state in a single session for moderately up to well-trained athletes. © Georg Thieme Verlag KG Stuttgart · New York.

Terrestrial Microgravity Model and Threshold Gravity Simulation using Magnetic Levitation

NASA Technical Reports Server (NTRS)

Ramachandran, N.

2005-01-01

What is the threshold gravity (minimum gravity level) required for the nominal functioning of the human system? What dosage is required? Do human cell lines behave differently in microgravity in response to an external stimulus? The critical need for such a gravity simulator is emphasized by recent experiments on human epithelial cells and lymphocytes on the Space Shuttle clearly showing that cell growth and function are markedly different from those observed terrestrially. Those differences are also dramatic between cells grown in space and those in Rotating Wall Vessels (RWV), or NASA bioreactor often used to simulate microgravity, indicating that although morphological growth patterns (three dimensional growth) can be successfully simulated using RWVs, cell function performance is not reproduced - a critical difference. If cell function is dramatically affected by gravity off-loading, then cell response to stimuli such as radiation, stress, etc. can be very different from terrestrial cell lines. Yet, we have no good gravity simulator for use in study of these phenomena. This represents a profound shortcoming for countermeasures research. We postulate that we can use magnetic levitation of cells and tissue, through the use of strong magnetic fields and field gradients, as a terrestrial microgravity model to study human cells. Specific objectives of the research are: 1. To develop a tried, tested and benchmarked terrestrial microgravity model for cell culture studies; 2. Gravity threshold determination; 3. Dosage (magnitude and duration) of g-level required for nominal functioning of cells; 4. Comparisons of magnetic levitation model to other models such as RWV, hind limb suspension, etc. and 5. Cellular response to reduced gravity levels of Moon and Mars. The paper will discuss experiments md modeling work to date in support of this project.

Threshold Gravity Determination and Artificial Gravity Studies Using Magnetic Levitation

NASA Technical Reports Server (NTRS)

Ramachandran, N.; Leslie, F.

2005-01-01

What is the threshold gravity (minimum gravity level) required for the nominal functioning of the human system? What dosage is required (magnitude and duration)? Do human cell lines behave differently in microgravity in response to an external stimulus? The critical need for a variable gravity simulator is emphasized by recent experiments on human epithelial cells and lymphocytes on the Space Shuttle clearly showing that cell growth and function are markedly different from those observed terrestrially. Those differences are also dramatic between cells grown in space and those in Rotating Wall Vessels (RWV), or NASA bioreactor often used to simulate microgravity, indicating that although morphological growth patterns (three dimensional growth) can be successfully simulated using RWVs, cell function performance is not reproduced - a critical difference. If cell function is dramatically affected by gravity off-loading, then cell response to stimuli such as radiation, stress, etc. can be very different from terrestrial cell lines. Yet, we have no good gravity simulator for use in study of these phenomena. This represents a profound shortcoming for countermeasures research. We postulate that we can use magnetic levitation of cells and tissue, through the use of strong magnetic fields and field gradients, as a terrestrial microgravity model to study human cells. Specific objectives of the research are: 1. To develop a tried, tested and benchmarked terrestrial microgravity model for cell culture studies; 2. Gravity threshold determination; 3. Dosage (magnitude and duration) of g-level required for nominal functioning of cells; 4. Comparisons of magnetic levitation model to other models such as RWV, hind limb suspension, etc. and 5. Cellular response to reduced gravity levels of Moon and Mars.

Is there a minimum intensity threshold for resistance training-induced hypertrophic adaptations?

PubMed

Schoenfeld, Brad J

2013-12-01

In humans, regimented resistance training has been shown to promote substantial increases in skeletal muscle mass. With respect to traditional resistance training methods, the prevailing opinion is that an intensity of greater than ~60 % of 1 repetition maximum (RM) is necessary to elicit significant increases in muscular size. It has been surmised that this is the minimum threshold required to activate the complete spectrum of fiber types, particularly those associated with the largest motor units. There is emerging evidence, however, that low-intensity resistance training performed with blood flow restriction (BFR) can promote marked increases in muscle hypertrophy, in many cases equal to that of traditional high-intensity exercise. The anabolic effects of such occlusion-based training have been attributed to increased levels of metabolic stress that mediate hypertrophy at least in part by enhancing recruitment of high-threshold motor units. Recently, several researchers have put forth the theory that low-intensity exercise (≤50 % 1RM) performed without BFR can promote increases in muscle size equal, or perhaps even superior, to that at higher intensities, provided training is carried out to volitional muscular failure. Proponents of the theory postulate that fatiguing contractions at light loads is simply a milder form of BFR and thus ultimately results in maximal muscle fiber recruitment. Current research indicates that low-load exercise can indeed promote increases in muscle growth in untrained subjects, and that these gains may be functionally, metabolically, and/or aesthetically meaningful. However, whether hypertrophic adaptations can equal that achieved with higher intensity resistance exercise (≤60 % 1RM) remains to be determined. Furthermore, it is not clear as to what, if any, hypertrophic effects are seen with low-intensity exercise in well-trained subjects as experimental studies on the topic in this population are lacking. Practical implications of these findings are discussed.

The limits of earthquake early warning: Timeliness of ground motion estimates

USGS Publications Warehouse

Minson, Sarah E.; Meier, Men-Andrin; Baltay, Annemarie S.; Hanks, Thomas C.; Cochran, Elizabeth S.

2018-01-01

The basic physics of earthquakes is such that strong ground motion cannot be expected from an earthquake unless the earthquake itself is very close or has grown to be very large. We use simple seismological relationships to calculate the minimum time that must elapse before such ground motion can be expected at a distance from the earthquake, assuming that the earthquake magnitude is not predictable. Earthquake early warning (EEW) systems are in operation or development for many regions around the world, with the goal of providing enough warning of incoming ground shaking to allow people and automated systems to take protective actions to mitigate losses. However, the question of how much warning time is physically possible for specified levels of ground motion has not been addressed. We consider a zero-latency EEW system to determine possible warning times a user could receive in an ideal case. In this case, the only limitation on warning time is the time required for the earthquake to evolve and the time for strong ground motion to arrive at a user’s location. We find that users who wish to be alerted at lower ground motion thresholds will receive more robust warnings with longer average warning times than users who receive warnings for higher ground motion thresholds. EEW systems have the greatest potential benefit for users willing to take action at relatively low ground motion thresholds, whereas users who set relatively high thresholds for taking action are less likely to receive timely and actionable information.

The limits of earthquake early warning: Timeliness of ground motion estimates

PubMed Central

Hanks, Thomas C.

2018-01-01

The basic physics of earthquakes is such that strong ground motion cannot be expected from an earthquake unless the earthquake itself is very close or has grown to be very large. We use simple seismological relationships to calculate the minimum time that must elapse before such ground motion can be expected at a distance from the earthquake, assuming that the earthquake magnitude is not predictable. Earthquake early warning (EEW) systems are in operation or development for many regions around the world, with the goal of providing enough warning of incoming ground shaking to allow people and automated systems to take protective actions to mitigate losses. However, the question of how much warning time is physically possible for specified levels of ground motion has not been addressed. We consider a zero-latency EEW system to determine possible warning times a user could receive in an ideal case. In this case, the only limitation on warning time is the time required for the earthquake to evolve and the time for strong ground motion to arrive at a user’s location. We find that users who wish to be alerted at lower ground motion thresholds will receive more robust warnings with longer average warning times than users who receive warnings for higher ground motion thresholds. EEW systems have the greatest potential benefit for users willing to take action at relatively low ground motion thresholds, whereas users who set relatively high thresholds for taking action are less likely to receive timely and actionable information. PMID:29750190

Exploring Dutch surgeons' views on volume-based policies: a qualitative interview study.

PubMed

Mesman, Roos; Faber, Marjan J; Westert, Gert P; Berden, Bart

2018-01-01

Objective In many countries, the evidence for volume-outcome associations in surgery has been transferred into policy. Despite the large body of research that exists on the topic, qualitative studies aimed at surgeons' views on, and experiences with, these volume-based policies are lacking. We interviewed Dutch surgeons to gain more insight into the implications of volume-outcome policies for daily clinical practice, as input for effective surgical quality improvement. Methods Semi-structured interviews were conducted with 20 purposively selected surgeons from a stratified sample for hospital type and speciality. The interviews were recorded, transcribed verbatim and underwent inductive content analysis. Results Two overarching themes were inductively derived from the data: (1) minimum volume standards and (2) implications of volume-based policies. Although surgeons acknowledged the premise 'more is better', they were critical about the validity and underlying evidence for minimum volume standards. Patients often inquire about caseload, which is met with both understanding and discomfort. Surgeons offered many examples of controversies surrounding the process of determining thresholds as well as the ways in which health insurers use volume as a purchasing criterion. Furthermore, being held accountable for caseload may trigger undesired strategic behaviour, such as unwarranted operations. Volume-based policies also have implications for the survival of low-volume providers and affect patient travel times, although the latter is not necessarily problematic in the Dutch context. Conclusions Surgeons in this study acknowledged that more volume leads to better quality. However, validity issues, undesired strategic behaviour and the ways in which minimum volume standards are established and applied have made surgeons critical of current policy practice. These findings suggest that volume remains a controversial quality measure and causes polarization that is not conducive to a collective effort for quality improvement. We recommend enforcing thresholds that are based on the best achievable level of consensus and assessing additional criteria when passing judgement on quality of care.

545 N McClurg Ct, February 2015, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation during the excavation process did not exceed theinstrument threshold previously stated and ranged from a minimum of 5,700 cpm to a maximum of 13,500cpm unshielded.

356 E Grand, July 2016, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavations and of the spoil during the excavation process didnot exceed the instrument threshold previously stated and ranged from a minimum of 5,000 cpm to amaximum of 9,600 cpm unshielded.

237 E Ontario, July 2016, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavations and of the spoil during the excavation process didnot exceed the instrument threshold previously stated and ranged from a minimum of 8,600 cpm to amaximum of 9,500 cpm unshielded.

226-228 E Ontario St, December 2014, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation during the excavation process did not exceed theunshielded instrument threshold previously stated and ranged from a minimum of 6,200 cpm to amaximum of 8,800 cpm unshielded.

441 E Ontario, August 2010, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gammameasurements within the excavation and the spoil materials generated during the excavation process did notexceed the respective threshold values previously stated and ranged from a minimum of 5,200 cpm to amaximum of 9,200 cpm.

380 E. North Water St, April 2016, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation during the excavation process did not exceed theinstrument threshold previously stated and ranged from a minimum of 6,800 cpm to a maximum of 12,100cpm unshielded.

Microdisk Injection Lasers for the 1.27-μm Spectral Range

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kryzhanovskaya, N. V.; Maximov, M. V.; Blokhin, S. A.

2016-03-15

Microdisk injection lasers on GaAs substrates, with a minimum diameter of 15 μm and an active region based on InAs/InGaAs quantum dots, are fabricated. The lasers operate in the continuous-wave mode at room temperature without external cooling. The lasing wavelength is around 1.27 μm at a minimum threshold current of 1.6 mA. The specific thermal resistance is estimated to be 5 × 10–3 °C cm{sup 2}/W.

Method and apparatus for biological sequence comparison

DOEpatents

Marr, T.G.; Chang, W.I.

1997-12-23

A method and apparatus are disclosed for comparing biological sequences from a known source of sequences, with a subject (query) sequence. The apparatus takes as input a set of target similarity levels (such as evolutionary distances in units of PAM), and finds all fragments of known sequences that are similar to the subject sequence at each target similarity level, and are long enough to be statistically significant. The invention device filters out fragments from the known sequences that are too short, or have a lower average similarity to the subject sequence than is required by each target similarity level. The subject sequence is then compared only to the remaining known sequences to find the best matches. The filtering member divides the subject sequence into overlapping blocks, each block being sufficiently large to contain a minimum-length alignment from a known sequence. For each block, the filter member compares the block with every possible short fragment in the known sequences and determines a best match for each comparison. The determined set of short fragment best matches for the block provide an upper threshold on alignment values. Regions of a certain length from the known sequences that have a mean alignment value upper threshold greater than a target unit score are concatenated to form a union. The current block is compared to the union and provides an indication of best local alignment with the subject sequence. 5 figs.

Method and apparatus for biological sequence comparison

DOEpatents

Marr, Thomas G.; Chang, William I-Wei

1997-01-01

A method and apparatus for comparing biological sequences from a known source of sequences, with a subject (query) sequence. The apparatus takes as input a set of target similarity levels (such as evolutionary distances in units of PAM), and finds all fragments of known sequences that are similar to the subject sequence at each target similarity level, and are long enough to be statistically significant. The invention device filters out fragments from the known sequences that are too short, or have a lower average similarity to the subject sequence than is required by each target similarity level. The subject sequence is then compared only to the remaining known sequences to find the best matches. The filtering member divides the subject sequence into overlapping blocks, each block being sufficiently large to contain a minimum-length alignment from a known sequence. For each block, the filter member compares the block with every possible short fragment in the known sequences and determines a best match for each comparison. The determined set of short fragment best matches for the block provide an upper threshold on alignment values. Regions of a certain length from the known sequences that have a mean alignment value upper threshold greater than a target unit score are concatenated to form a union. The current block is compared to the union and provides an indication of best local alignment with the subject sequence.

Wind erosion in semiarid landscapes: Predictive models and remote sensing methods for the influence of vegetation

NASA Technical Reports Server (NTRS)

Musick, H. Brad; Truman, C. Randall; Trujillo, Steven M.

1992-01-01

Wind erosion in semi-arid regions is a significant problem for which the sheltering effect of rangeland vegetation is poorly understood. Individual plants may be considered as porous roughness elements which absorb or redistribute the wind's momentum. The saltation threshold is the minimum wind velocity at which soil movement begins. The dependence of the saltation threshold on geometrical parameters of a uniform roughness array was studied in a wind tunnel. Both solid and porous elements were used to determine relationships between canopy structure and the threshold velocity for soil transport. The development of a predictive relation for the influence of vegetation canopy structure on wind erosion of soil is discussed.

Comparison of the diagnostic accuracy, sensitivity and specificity of four odontological methods for age evaluation in Italian children at the age threshold of 14 years using ROC curves.

PubMed

Pinchi, Vilma; Pradella, Francesco; Vitale, Giulia; Rugo, Dario; Nieri, Michele; Norelli, Gian-Aristide

2016-01-01

The age threshold of 14 years is relevant in Italy as the minimum age for criminal responsibility. It is of utmost importance to evaluate the diagnostic accuracy of every odontological method for age evaluation considering the sensitivity, or the ability to estimate the true positive cases, and the specificity, or the ability to estimate the true negative cases. The research aims to compare the specificity and sensitivity of four commonly adopted methods of dental age estimation - Demirjian, Haavikko, Willems and Cameriere - in a sample of Italian children aged between 11 and 16 years, with an age threshold of 14 years, using receiver operating characteristic curves and the area under the curve (AUC). In addition, new decision criteria are developed to increase the accuracy of the methods. Among the four odontological methods for age estimation adopted in the research, the Cameriere method showed the highest AUC in both female and male cohorts. The Cameriere method shows a high degree of accuracy at the age threshold of 14 years. To adopt the Cameriere method to estimate the 14-year age threshold more accurately, however, it is suggested - according to the Youden index - that the decision criterion be set at the lower value of 12.928 for females and 13.258 years for males, obtaining a sensitivity of 85% and specificity of 88% in females, and a sensitivity of 77% and specificity of 92% in males. If a specificity level >90% is needed, the cut-off point should be set at 12.959 years (82% sensitivity) for females. © The Author(s) 2015.

Definition of temperature thresholds: the example of the French heat wave warning system.

PubMed

Pascal, Mathilde; Wagner, Vérène; Le Tertre, Alain; Laaidi, Karine; Honoré, Cyrille; Bénichou, Françoise; Beaudeau, Pascal

2013-01-01

Heat-related deaths should be somewhat preventable. In France, some prevention measures are activated when minimum and maximum temperatures averaged over three days reach city-specific thresholds. The current thresholds were computed based on a descriptive analysis of past heat waves and on local expert judgement. We tested whether a different method would confirm these thresholds. The study was set in the six cities of Paris, Lyon, Marseille, Nantes, Strasbourg and Limoges between 1973 and 2003. For each city, we estimated the excess in mortality associated with different temperature thresholds, using a generalised additive model, controlling for long-time trends, seasons and days of the week. These models were used to compute the mortality predicted by different percentiles of temperatures. The thresholds were chosen as the percentiles associated with a significant excess mortality. In all cities, there was a good correlation between current thresholds and the thresholds derived from the models, with 0°C to 3°C differences for averaged maximum temperatures. Both set of thresholds were able to anticipate the main periods of excess mortality during the summers of 1973 to 2003. A simple method relying on descriptive analysis and expert judgement is sufficient to define protective temperature thresholds and to prevent heat wave mortality. As temperatures are increasing along with the climate change and adaptation is ongoing, more research is required to understand if and when thresholds should be modified.

Intense cold and mortality in Castile-La Mancha (Spain): study of mortality trigger thresholds from 1975 to 2003

NASA Astrophysics Data System (ADS)

Miron, Isidro J.; Montero, Juan Carlos; Criado-Alvarez, Juan José; Linares, Cristina; Díaz, Julio

2012-01-01

Studies on temperature-mortality time trends especially address heat, so that any contribution on the subject of cold is necessarily of interest. This study describes the modification of the lagged effects of cold on mortality in Castile-La Mancha from 1975 to 2003, with the novelty of also approaching this aspect in terms of mortality trigger thresholds. Cross-correlation functions (CCFs) were thus established with 15 lags, after application of ARIMA models to the mortality data and minimum daily temperatures (from November to March), and the results for the periods 1975-1984, 1985-1994 and 1995-2003 were then compared. In addition, daily mortality residuals for the periods 1975-1989 and 1990-2003 were related to minimum temperatures grouped in 2°C intervals, with a cold threshold temperature being obtained in cases where such residuals increased significantly ( p < 0.05) with respect to the mean for the study period. A cold-related mortality trigger threshold of -3°C was obtained for Ciudad Real for the period 1990-2003. The significant number of lags ( p < 0.05) in the CCFs declined every 10 years in Toledo (5-2-0), Cuenca (4-2-0), Albacete (4-3-0) and Ciudad Real (3-2-1). This meant that, while the trend in cold-related mortality trigger thresholds in the region could not be ascertained, it was possible to establish a reduction in the lagged effects of cold on mortality, attributable to the improvement in socio-economic conditions over the study period. Evidence was shown of the effects of cold on mortality, a finding that renders the adoption of preventive measures advisable in any case where intense cold is forecast.

450 N. Cityfront Plaza, October 2016, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavations and of the spoil during the excavation process didnot exceed the instrument threshold previously stated and ranged from a minimum of 4,400 cpm to amaximum of 6,000 cpm unshielded.

465 E. Illinois St., February 2015, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

Field gamma measurements within the excavation and the spoil materials generatedduring the excavation process did not exceed the field instrument threshold previously stated and rangedfrom a minimum of 10,000 cpm to a maximum of 15,500 cpm unshielded.

465 N. Park Ave, October 2016, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavations and of the spoil during the excavation process didnot exceed the instrument threshold previously stated and ranged from a minimum of 4,100 cpm to amaximum of 16,600 cpm unshielded.

300 E Randolph, May 2011, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation andthe spoil materials generated during the excavation process did not exceed the respective threshold valuespreviously stated and ranged from a minimum of 4,900 cpm to a maximum of 9,300 cpm.

151 N. Field Blvd., August 2010, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within theexcavation and the spoil materials generated during the excavation process did not exceed therespective threshold values previously stated and ranged from a minimum of 2,400 cpm to amaximum of 3,000 cpm.

400 E. Monroe, January 2011, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The fieldgamma measurements within the excavation and the spoil materials generated during the excavationprocess did not exceed the respective threshold values previously stated and ranged from a minimum of4,867 cpm to a maximum of 7,351 cpm.

165 E Ontario, October 2010, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation and the spoil materials generatedduring the excavation process did not exceed the respective threshold values previously stated andranged from a minimum of 2, 150 cpm to a maximum of 6,270 cpm.

659-663 N Michigan, March 2011, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation and the spoilmaterials generated during the excavation process did not exceed the respective threshold valuepreviously stated and ranged from a minimum of 4,180 cpm to a maximum of 5,545 cpm.

Diamond Pixel Detectors

NASA Astrophysics Data System (ADS)

Adam, W.; Berdermann, E.; Bergonzo, P.; Bertuccio, G.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; D'Angelo, P.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Doroshenko, J.; Dulinski, W.; van Eijk, B.; Fallou, A.; Fizzotti, F.; Foster, J.; Foulon, F.; Friedl, M.; Gan, K. K.; Gheeraert, E.; Gobbi, B.; Grim, G. P.; Hallewell, G.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Kass, R.; Koeth, T.; Krammer, M.; Lander, R.; Logiudice, A.; Lu, R.; mac Lynne, L.; Manfredotti, C.; Meier, D.; Mishina, M.; Moroni, L.; Oh, A.; Pan, L. S.; Pernicka, M.; Perera, L.; Pirollo, S.; Plano, R.; Procario, M.; Riester, J. L.; Roe, S.; Rott, C.; Rousseau, L.; Rudge, A.; Russ, J.; Sala, S.; Sampietro, M.; Schnetzer, S.; Sciortino, S.; Stelzer, H.; Stone, R.; Suter, B.; Tapper, R. J.; Tesarek, R.; Trischuk, W.; Tromson, D.; Vittone, E.; Wedenig, R.; Weilhammer, P.; White, C.; Zeuner, W.; Zoeller, M.

2001-06-01

Diamond based pixel detectors are a promising radiation-hard technology for use at the LHC. We present first results on a CMS diamond pixel sensor. With a threshold setting of 2000 electrons, an average pixel efficiency of 78% was obtained for normally incident minimum ionizing particles.

633 N. Michigan Ave, May 2016, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavations and of the spoil during the excavation process didnot exceed the instrument threshold previously stated and ranged from a minimum of 4,400 cpm to amaximum of 5,900 cpm unshielded.

157 - 165 E. Ohio, May 2016, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavations and of the spoil during the excavation process didnot exceed the instrument threshold previously stated and ranged from a minimum of 5,000 cpm to amaximum of 5,900 cpm unshielded.

512 N McClurg, August 2010, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurementswithin the excavation and the spoil materials generated during the excavation process did not exceed therespective threshold values previously stated and ranged from a minimum of 6,500 cpm to a maximum of9,500 cpm.

Hearing impairment related to age in Usher syndrome types 1B and 2A.

PubMed

Wagenaar, M; van Aarem, A; Huygen, P; Pieke-Dahl, S; Kimberling, W; Cremers, C

1999-04-01

To evaluate hearing impairment in 2 common genetic subtypes of Usher syndrome, USH1B and USH2A. Cross-sectional analysis of hearing threshold related to age in patients with genotypes determined by linkage and mutation analysis. Otolaryngology department, university referral center. Nineteen patients with USH1B and 27 with USH2A were examined. All participants were living in the Netherlands and Belgium. Pure tone audiometry of the best ear at last visit. The patients with USH1B had residual hearing without age dependence, with minimum thresholds of 80, 95, and 120 dB at 0.25, 0.5, and 1 to 2 kHz, respectively. Mean thresholds of patients with USH2A were about 45 to 55 dB better than these minimum values. Distinctive audiographic features of patients with USH2A were maximum hearing thresholds of 70, 80, and 100 dB at 0.25, 0.5, and 1 kHz, respectively, only at younger than 40 years. Progression of hearing impairment in USH2A was 0.7 dB/y on average for 0.25 to 4 kHz and could not be explained by presbyacusis alone. The USH1B and USH2A can be easily distinguished by hearing impairment at younger than 40 years at the low frequencies. Hearing impairment in our patients with USH2A could be characterized as progressive.

The Gap Detection Test: Can It Be Used to Diagnose Tinnitus?

PubMed Central

Boyen, Kris; Başkent, Deniz

2015-01-01

Objectives: Animals with induced tinnitus showed difficulties in detecting silent gaps in sounds, suggesting that the tinnitus percept may be filling the gap. The main purpose of this study was to evaluate the applicability of this approach to detect tinnitus in human patients. The authors first hypothesized that gap detection would be impaired in patients with tinnitus, and second, that gap detection would be more impaired at frequencies close to the tinnitus frequency of the patient. Design: Twenty-two adults with bilateral tinnitus, 20 age-matched and hearing loss–matched subjects without tinnitus, and 10 young normal-hearing subjects participated in the study. To determine the characteristics of the tinnitus, subjects matched an external sound to their perceived tinnitus in pitch and loudness. To determine the minimum detectable gap, the gap threshold, an adaptive psychoacoustic test was performed three times by each subject. In this gap detection test, four different stimuli, with various frequencies and bandwidths, were presented at three intensity levels each. Results: Similar to previous reports of gap detection, increasing sensation level yielded shorter gap thresholds for all stimuli in all groups. Interestingly, the tinnitus group did not display elevated gap thresholds in any of the four stimuli. Moreover, visual inspection of the data revealed no relation between gap detection performance and perceived tinnitus pitch. Conclusions: These findings show that tinnitus in humans has no effect on the ability to detect gaps in auditory stimuli. Thus, the testing procedure in its present form is not suitable for clinical detection of tinnitus in humans. PMID:25822647

Metacognition Is Necessary for the Emergence of Motivation in People With Schizophrenia Spectrum Disorders: A Necessary Condition Analysis.

PubMed

Luther, Lauren; Bonfils, Kelsey A; Firmin, Ruth L; Buck, Kelly D; Choi, Jimmy; Dimaggio, Giancarlo; Popolo, Raffaele; Minor, Kyle S; Lysaker, Paul H

2017-12-01

Metacognition deficits are a putative cause of reduced motivation in people with schizophrenia spectrum disorders. However, it is unclear whether certain levels of metacognition are necessary for motivation to emerge. This study used a Necessary Condition Analysis to test whether metacognition was necessary for the presence of motivation and to identify the minimum level of metacognition necessary for high motivation to be possible in people with schizophrenia spectrum disorders (N = 175). Participants completed clinician-rated measures of metacognition and motivation. Necessary Condition Analysis revealed that metacognition is a necessary condition for motivation and that high levels of motivation were only possible, although not guaranteed, when at least a basic level of metacognition was present. The findings suggest that metacognition is a necessary building block for the development of motivation. Results suggest that targeting metacognition may be essential for improving motivation among people with schizophrenia spectrum disorders who do not meet this metacognition threshold.

CARA Risk Assessment Thresholds

NASA Technical Reports Server (NTRS)

Hejduk, M. D.

2016-01-01

Warning remediation threshold (Red threshold): Pc level at which warnings are issued, and active remediation considered and usually executed. Analysis threshold (Green to Yellow threshold): Pc level at which analysis of event is indicated, including seeking additional information if warranted. Post-remediation threshold: Pc level to which remediation maneuvers are sized in order to achieve event remediation and obviate any need for immediate follow-up maneuvers. Maneuver screening threshold: Pc compliance level for routine maneuver screenings (more demanding than regular Red threshold due to additional maneuver uncertainty).

Comparison of characteristics observed in tinnitus patients with unilateral vs bilateral symptoms, with both normal hearing threshold and distortion-product otoacoustic emissions.

PubMed

Zagólski, Olaf; Stręk, Paweł

2017-02-01

Tinnitus characteristics in normal-hearing patients differ between the groups with unilateral and bilateral complaints. The study was to determine the differences between tinnitus characteristics observed in patients with unilateral vs bilateral symptoms and normal hearing threshold, as well as normal results of distortion-product otoacoustic emissions (DPOAEs). The patients answered questions concerning tinnitus duration, laterality, character, accompanying symptoms, and circumstances of onset. The results of tympanometry, auditory brainstem responses, tinnitus likeness spectrum, minimum masking level (MML), and uncomfortable loudness level were evaluated. Records of 380 tinnitus sufferers were examined. Patients with abnormal audiograms and/or DPOAEs were excluded. The remaining 66 participants were divided into groups with unilateral and bilateral tinnitus. Unilateral tinnitus in normal-hearing patients was diagnosed twice more frequently than bilateral. Tinnitus pitch was higher in the group with bilateral tinnitus (p < .001). MML was lower in unilateral tinnitus (p < .05). Mean age of patients was higher in the unilateral tinnitus group (p < .05). Mean tinnitus duration was longer (p < .05) and hypersensitivity to sound was more frequent (p < .05) in the bilateral tinnitus group. Repeated exposure to excessive noise was the most frequent cause in the bilateral tinnitus group.

Direct imaging of band profile in single layer MoS2 on graphite: quasiparticle energy gap, metallic edge states, and edge band bending.

PubMed

Zhang, Chendong; Johnson, Amber; Hsu, Chang-Lung; Li, Lain-Jong; Shih, Chih-Kang

2014-05-14

Using scanning tunneling microscopy and spectroscopy, we probe the electronic structures of single layer MoS2 on graphite. The apparent quasiparticle energy gap of single layer MoS2 is measured to be 2.15 ± 0.06 eV at 77 K, albeit a higher second conduction band threshold at 0.2 eV above the apparent conduction band minimum is also observed. Combining it with photoluminescence studies, we deduce an exciton binding energy of 0.22 ± 0.1 eV (or 0.42 eV if the second threshold is use), a value that is lower than current theoretical predictions. Consistent with theoretical predictions, we directly observe metallic edge states of single layer MoS2. In the bulk region of MoS2, the Fermi level is located at 1.8 eV above the valence band maximum, possibly due to the formation of a graphite/MoS2 heterojunction. At the edge, however, we observe an upward band bending of 0.6 eV within a short depletion length of about 5 nm, analogous to the phenomena of Fermi level pinning of a 3D semiconductor by metallic surface states.

Performance of bulk oil circuit breaker (BOCB) influenced by its parameters (Case study at the substation of Bogor Baru)

NASA Astrophysics Data System (ADS)

Goeritno, Arief; Rasiman, Syofyan

2017-06-01

Performance examination of the bulk oil circuit breaker that is influenced by its parameters at the Substation of Bogor Baru (the State Electricity Company = PLN) has been done. It is found that (1) dielectric strength of oil still qualifies as an insulating and cooling medium, because the average value of the measurement result is still above the minimum value allowed, where the minimum limit of 80 kV/2.5 cm or 32 kV/cm; (2) the simultaneity of the CB's contacts is still eligible, so that the BOCB can still be operated, because the difference of time between the highest and lowest values when the BOCB's contacts are opened/closed are less than (Δt<) 10 milliseconds (if meeting the PLN standards as recommended by Alsthom); and (3) the parameter of resistance according to the standards, where (i) the resistance of insulation has a value far above the allowed threshold, while the minimum standards are above 2,000 Mn (if meeting the ANSI standards) or on the value of 2,000 MΩ (if meeting PLN standards), (ii) the resistance of contacts has a value far above the allowed threshold, while the minimum standards are below 350 µΩ (if meeting ANSI standards) or on the value of 200 µΩ (if meeting PLN standards). The resistance of grounding is equal to the maximum limit specified, while the maximum standard is on the value of 0.5 Ω (if meeting PLN standard).

Introduction of a National Minimum Wage Reduced Depressive Symptoms in Low-Wage Workers: A Quasi-Natural Experiment in the UK.

PubMed

Reeves, Aaron; McKee, Martin; Mackenbach, Johan; Whitehead, Margaret; Stuckler, David

2017-05-01

Does increasing incomes improve health? In 1999, the UK government implemented minimum wage legislation, increasing hourly wages to at least £3.60. This policy experiment created intervention and control groups that can be used to assess the effects of increasing wages on health. Longitudinal data were taken from the British Household Panel Survey. We compared the health effects of higher wages on recipients of the minimum wage with otherwise similar persons who were likely unaffected because (1) their wages were between 100 and 110% of the eligibility threshold or (2) their firms did not increase wages to meet the threshold. We assessed the probability of mental ill health using the 12-item General Health Questionnaire. We also assessed changes in smoking, blood pressure, as well as hearing ability (control condition). The intervention group, whose wages rose above the minimum wage, experienced lower probability of mental ill health compared with both control group 1 and control group 2. This improvement represents 0.37 of a standard deviation, comparable with the effect of antidepressants (0.39 of a standard deviation) on depressive symptoms. The intervention group experienced no change in blood pressure, hearing ability, or smoking. Increasing wages significantly improves mental health by reducing financial strain in low-wage workers. © 2016 The Authors. Health Economics published by John Wiley & Sons Ltd. © 2016 The Authors. Health Economics published by John Wiley & Sons Ltd.

Minimum follow-up time required for the estimation of statistical cure of cancer patients: verification using data from 42 cancer sites in the SEER database

PubMed Central

Tai, Patricia; Yu, Edward; Cserni, Gábor; Vlastos, Georges; Royce, Melanie; Kunkler, Ian; Vinh-Hung, Vincent

2005-01-01

Background The present commonly used five-year survival rates are not adequate to represent the statistical cure. In the present study, we established the minimum number of years required for follow-up to estimate statistical cure rate, by using a lognormal distribution of the survival time of those who died of their cancer. We introduced the term, threshold year, the follow-up time for patients dying from the specific cancer covers most of the survival data, leaving less than 2.25% uncovered. This is close enough to cure from that specific cancer. Methods Data from the Surveillance, Epidemiology and End Results (SEER) database were tested if the survival times of cancer patients who died of their disease followed the lognormal distribution using a minimum chi-square method. Patients diagnosed from 1973–1992 in the registries of Connecticut and Detroit were chosen so that a maximum of 27 years was allowed for follow-up to 1999. A total of 49 specific organ sites were tested. The parameters of those lognormal distributions were found for each cancer site. The cancer-specific survival rates at the threshold years were compared with the longest available Kaplan-Meier survival estimates. Results The characteristics of the cancer-specific survival times of cancer patients who died of their disease from 42 cancer sites out of 49 sites were verified to follow different lognormal distributions. The threshold years validated for statistical cure varied for different cancer sites, from 2.6 years for pancreas cancer to 25.2 years for cancer of salivary gland. At the threshold year, the statistical cure rates estimated for 40 cancer sites were found to match the actuarial long-term survival rates estimated by the Kaplan-Meier method within six percentage points. For two cancer sites: breast and thyroid, the threshold years were so long that the cancer-specific survival rates could yet not be obtained because the SEER data do not provide sufficiently long follow-up. Conclusion The present study suggests a certain threshold year is required to wait before the statistical cure rate can be estimated for each cancer site. For some cancers, such as breast and thyroid, the 5- or 10-year survival rates inadequately reflect statistical cure rates, and highlight the need for long-term follow-up of these patients. PMID:15904508

Establishing Minimum Flow Requirements Based on Benthic Vegetation: What are Some Issues Related to Identifying Quantity of Inflow and Tools Used to Quantify Ecosystem Response?

NASA Astrophysics Data System (ADS)

Hunt, M. J.; Nuttle, W. K.; Cosby, B. J.; Marshall, F. E.

2005-05-01

Establishing minimum flow requirements in aquatic ecosystems is one way to stipulate controls on water withdrawals in a watershed. The basis of the determination is to identify the amount of flow needed to sustain a threshold ecological function. To develop minimum flow criteria an understanding of ecological response in relation to flow is essential. Several steps are needed including: (1) identification of important resources and ecological functions, (2) compilation of available information, (3) determination of historical conditions, (4) establishment of technical relationships between inflow and resources, and (5) identification of numeric criteria that reflect the threshold at which resources are harmed. The process is interdisciplinary requiring the integration of hydrologic and ecologic principles with quantitative assessments. The tools used quantify the ecological response and key questions related to how the quantity of flow influences the ecosystem are examined by comparing minimum flow determination in two different aquatic systems in South Florida. Each system is characterized by substantial hydrologic alteration. The first, the Caloosahatchee River is a riverine system, located on the southwest coast of Florida. The second, the Everglades- Florida Bay ecotone, is a wetland mangrove ecosystem, located on the southern tip of the Florida peninsula. In both cases freshwater submerged aquatic vegetation (Vallisneria americana or Ruppia maritima), located in areas of the saltwater- freshwater interface has been identified as a basis for minimum flow criteria. The integration of field studies, laboratory studies, and literature review was required. From this information we developed ecological modeling tools to quantify and predict plant growth in response to varying environmental variables. Coupled with hydrologic modeling tools questions relating to the quantity and timing of flow and ecological consequences in relation to normal variability are addressed.

Effect of Endurance Training on The Lactate and Glucose Minimum Intensities

PubMed Central

Junior, Pedro B.; de Andrade, Vitor L.; Campos, Eduardo Z.; Kalva-Filho, Carlos A.; Zagatto, Alessandro M.; de Araújo, Gustavo G.; Papoti, Marcelo

2018-01-01

Due to the controversy about the sensitive of lactate minimum intensity (LMI) to training and the need to develop other tool for aerobic fitness evaluation, the purpose of this study was to analyze the sensitivity of glucose minimum intensity (GMI) and LMI to endurance training. Eight trained male cyclists (21.4 ± 1.9 years, 67.6 ± 7.5 kg and 1.72 ± 0.10 m) were evaluated twice, before and after 12 weeks of training. GMI and LMI were calculated, respectively, by the lowest blood glucose and lactate values attained during an incremental test performed after a hyperlactemia induction, and VO2max was determined during standard incremental effort. The training was prescribed in three different zones and controlled by heart rate (HR). The training distribution was equivalent to 59.7%, 25.0% and 15.3% below, at and above anaerobic threshold HR respectively. The anaerobic threshold evaluated by GMI and LMI improvement 9.89 ± 4.35% and 10.28 ± 9.89 respectively, after training, but the VO2max 2.52 ± 1.81%. No differences were found between GMI and LMI in pre (218.2 ± 22.1 vs 215.0 ± 18.6 W) and post (240.6 ± 22.9 vs 237.5 ± 18.8 W) training situations. LMI and GMI were sensitive to 12-week aerobic training in cyclist; thus, both protocols can be used to assess aerobic adaptation, athletes diagnostic and prescribe training. Key points The lactate and glucose minimum intensities (GMI) can be used for monitoring training effects on cyclists Although both GMI and lactate minimum intensities are important index of aerobic fitness, they cannot be used to determine aerobic fitness. The polarized training was effective for improvements of maximal oxygen uptake on trained cyclists. PMID:29535585

I. RENAL THRESHOLDS FOR HEMOGLOBIN IN DOGS

PubMed Central

Lichty, John A.; Havill, William H.; Whipple, George H.

1932-01-01

We use the term "renal threshold for hemoglobin" to indicate the smallest amount of hemoglobin which given intravenously will effect the appearance of recognizable hemoglobin in the urine. The initial renal threshold level for dog hemoglobin is established by the methods employed at an average value of 155 mg. hemoglobin per kilo body weight with maximal values of 210 and minimal of 124. Repeated daily injections of hemoglobin will depress this initial renal threshold level on the average 46 per cent with maximal values of 110 and minimal values of 60 mg. hemoglobin per kilo body weight. This minimal or depression threshold is relatively constant if the injections are continued. Rest periods without injections cause a return of the renal threshold for hemoglobin toward the initial threshold levels—recovery threshold level. Injections of hemoglobin below the initial threshold level but above the minimal or depression threshold will eventually reduce the renal threshold for hemoglobin to its depression threshold level. We believe the depression threshold or minimal renal threshold level due to repeated hemoglobin injections is a little above the glomerular threshold which we assume is the base line threshold for hemoglobin. Our reasons for this belief in the glomerular threshold are given above and in the other papers of this series. PMID:19870016

A Short-term ESPERTA-based Forecast Tool for Moderate-to-extreme Solar Proton Events

NASA Astrophysics Data System (ADS)

Laurenza, M.; Alberti, T.; Cliver, E. W.

2018-04-01

The ESPERTA (Empirical model for Solar Proton Event Real Time Alert) forecast tool has a Probability of Detection (POD) of 63% for all >10 MeV events with proton peak intensity ≥10 pfu (i.e., ≥S1 events, S1 referring to minor storms on the NOAA Solar Radiation Storms scale), from 1995 to 2014 with a false alarm rate (FAR) of 38% and a median (minimum) warning time (WT) of ∼4.8 (0.4) hr. The NOAA space weather scale includes four additional categories: moderate (S2), strong (S3), severe (S4), and extreme (S5). As S1 events have only minor impacts on HF radio propagation in the polar regions, the effective threshold for significant space radiation effects appears to be the S2 level (100 pfu), above which both biological and space operation impacts are observed along with increased effects on HF propagation in the polar regions. We modified the ESPERTA model to predict ≥S2 events and obtained a POD of 75% (41/55) and an FAR of 24% (13/54) for the 1995–2014 interval with a median (minimum) WT of ∼1.7 (0.2) hr based on predictions made at the time of the S1 threshold crossing. The improved performance of ESPERTA for ≥S2 events is a reflection of the big flare syndrome, which postulates that the measures of the various manifestations of eruptive solar flares increase as one considers increasingly larger events.

Option pricing: a flexible tool to disseminate shared savings contracts.

PubMed

Friedberg, Mark W; Buendia, Anthony M; Lauderdale, Katherine E; Hussey, Peter S

2013-08-01

Due to volatility in healthcare costs, shared savings contracts can create systematic financial losses for payers, especially when contracting with smaller providers. To improve the business case for shared savings, we calculated the prices of financial options that payers can "sell" to providers to offset these losses. Using 2009 to 2010 member-level total cost of care data from a large commercial health plan, we calculated option prices by applying a bootstrap simulation procedure. We repeated these simulations for providers of sizes ranging from 500 to 60,000 patients and for shared savings contracts with and without key design features (minimum savings thresholds,bonus caps, cost outlier truncation, and downside risk) and under assumptions of zero, 1%, and 2% real cost reductions due to the shared savings contracts. Assuming no real cost reduction and a 50% shared savings rate, per patient option prices ranged from $225 (3.1% of overall costs) for 500-patient providers to $23 (0.3%) for 60,000-patient providers. Introducing minimum savings thresholds, bonus caps, cost outlier truncation, and downside risk reduced these option prices. Option prices were highly sensitive to the magnitude of real cost reductions. If shared savings contracts cause 2% reductions in total costs, option prices fall to zero for all but the smallest providers. Calculating the prices of financial options that protect payers and providers from downside risk can inject flexibility into shared savings contracts, extend such contracts to smaller providers, and clarify the tradeoffs between different contract designs, potentially speeding the dissemination of shared savings.

Atlas of interoccurrence intervals for selected thresholds of daily precipitation in Texas

USGS Publications Warehouse

Asquith, William H.; Roussel, Meghan C.

2003-01-01

A Poisson process model is used to define the distribution of interoccurrence intervals of daily precipitation in Texas. A precipitation interoccurrence interval is the time period between two successive rainfall events. Rainfall events are defined as daily precipitation equaling or exceeding a specified depth threshold. Ten precipitation thresholds are considered: 0.05, 0.10, 0.25, 0.50, 0.75, 1.0, 1.5, 2.0, 2.5, and 3.0 inches. Site-specific mean interoccurrence interval and ancillary statistics are presented for each threshold and for each of 1,306 National Weather Service daily precipitation gages. Maps depicting the spatial variation across Texas of the mean interoccurrence interval for each threshold are presented. The percent change from the statewide standard deviation of the interoccurrence intervals to the root-mean-square error ranges from a magnitude minimum of (negative) -24 to a magnitude maximum of -60 percent for the 0.05- and 2.0-inch thresholds, respectively. Because of the substantial negative percent change, the maps are considered more reliable estimators of the mean interoccurrence interval for most locations in Texas than the statewide mean values.

How insurance affects altruistic provision in threshold public goods games.

PubMed

Zhang, Jianlei; Zhang, Chunyan; Cao, Ming

2015-03-13

The occurrence and maintenance of cooperative behaviors in public goods systems have attracted great research attention across multiple disciplines. A threshold public goods game requires a minimum amount of contributions to be collected from a group of individuals for provision to occur. Here we extend the common binary-strategy combination of cooperation and defection by adding a third strategy, called insured cooperation, which corresponds to buying an insurance covering the potential loss resulted from the unsuccessful public goods game. Particularly, only the contributing agents can opt to be insured, which is an effort decreasing the amount of the potential loss occurring. Theoretical computations suggest that when agents face the potential aggregate risk in threshold public goods games, more contributions occur with increasing compensation from insurance. Moreover, permitting the adoption of insurance significantly enhances individual contributions and facilitates provision, especially when the required threshold is high. This work also relates the strategy competition outcomes to different allocation rules once the resulted contributions exceed the threshold point in populations nested within a dilemma.

A derivation of the stable cavitation threshold accounting for bubble-bubble interactions.

PubMed

Guédra, Matthieu; Cornu, Corentin; Inserra, Claude

2017-09-01

The subharmonic emission of sound coming from the nonlinear response of a bubble population is the most used indicator for stable cavitation. When driven at twice their resonance frequency, bubbles can exhibit subharmonic spherical oscillations if the acoustic pressure amplitude exceeds a threshold value. Although various theoretical derivations exist for the subharmonic emission by free or coated bubbles, they all rest on the single bubble model. In this paper, we propose an analytical expression of the subharmonic threshold for interacting bubbles in a homogeneous, monodisperse cloud. This theory predicts a shift of the subharmonic resonance frequency and a decrease of the corresponding pressure threshold due to the interactions. For a given sonication frequency, these results show that an optimal value of the interaction strength (i.e. the number density of bubbles) can be found for which the subharmonic threshold is minimum, which is consistent with recently published experiments conducted on ultrasound contrast agents. Copyright © 2017 Elsevier B.V. All rights reserved.

501-59 E Illinois Street, January 2018, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavations and of the spoil during the excavation process did not exceed the instruments threshold previously stated and ranged from a minimum of 1,000 cpm to amaximum of 4,000 cpm shielded.

200 E Illinois St, December 2011, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

Field gamma measurements within the excavation and the spoil materials generated during the excavation process did not exceed the respective threshold value previously stated and ranged from a minimum of 7,100 cpm to amaximum of 9,400 cpm unshielded.

158 East Ontario, July 23, 2013, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

Field gamma measurements within the excavation and the spoil materials generated during the excavationprocess did not exceed the respective threshold values previously stated and ranged from a minimum of6,700 cpm to a maximum of 8,700 cpm unshielded.

639-640 E. Ohio St, August 2014, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation and of the spoil materials generatedduring the excavation process did not exceed the instrument threshold previously stated and ranged froma minimum of 5,100 cpm to a maximum of 6,700 cpm unshielded.

600-602 N Lakeshore Drive, March 2011, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The fieldgamma measurements within the excavation and the spoil materials generated during the excavationprocess did not exceed the respective threshold values previously stated and ranged from a minimum of4,382 cpm to a maximum of 7,907 cpm.

500-03 N. Peshtigo, October 2016, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation and of the spoil during the excavation process didnot exceed the instrument threshold previously stated and predominantly ranged from a minimum of5,600 cpm to a maximum of 11,000 cpm unshielded.

301-40 N. Field, October 2016, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavations and of the spoil during the excavation process didnot exceed the instrument threshold previously stated and predominantly ranged from a minimum of3,000 cpm to a maximum of 10,000 cpm unshielded.

Lindsay Light Radiological Survey 350 E Ohio St, May 2013

EPA Pesticide Factsheets

Field gamma measurements within the excavation and the spoil materials generated during the excavationprocess did not exceed the respective threshold values previously stated and ranged from a minimum of5,700 cpm to a maximum of 12,200 cpm unshielded.

405 E Illinois St, May 2014, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation and the spoil materials generatedduring the excavation process did not exceed the field instrument threshold previously stated and rangedfrom a minimum of 6,000 cpm to a maximum of 8,050 cpm unshielded

200-210 E. Ohio St., May 2014, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation and the spoil materials generatedduring the excavation process did not exceed the field instrument threshold previously stated and rangedfrom a minimum of 6,000 cpm to a maximum of 7,500 cpm unshielded

201 E South Water, December 2010, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation and the spoil materials generated during the excavation process did not exceed the respective threshold values previously stated and ranged from a minimum of7,234 cpm to a maximum of 9,872 cpm.

237 E. Ontario St., January 2017, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

Radiological Survey of Right-of-Way Utility Excavation. The measurements within the excavations and of the soil did not exceed the instrument USEPA threshold and ranged from a minimum of 4,800 cpm to a maximum of 8,300 cpm unshielded.

Exposure- and flux-based assessment of ozone risk to sugarcane plants

NASA Astrophysics Data System (ADS)

Moura, Bárbara Baêsso; Hoshika, Yasutomo; Ribeiro, Rafael Vasconcelos; Paoletti, Elena

2018-03-01

Ozone (O3) is a toxic oxidative air pollutant, with significant detrimental effects on crops. Sugarcane (Saccharum spp.) is an important crop with no O3 risk assessment performed so far. This study aimed to assess O3 risk to sugarcane plants by using exposure-based indices (AOT40 and W126) based on O3 concentrations in the air, and the flux-based index (PODy, where y is a threshold of uptake) that considers leaf O3 uptake and the influence of environmental conditions on stomatal conductance (gsto). Two sugarcane genotypes (IACSP94-2094 and IACSP95-5000) were subjected to a 90-day Free-Air Controlled Experiment (FACE) exposure at three levels of O3 concentrations: ambient (Amb); Amb x1.2; and Amb x1.4. Total above-ground biomass (AGB), stalk biomass (SB) and leaf biomass (LB) were evaluated and the potential biomass production in a clean air was estimated by assuming a theoretical clean atmosphere at 10 ppb as 24 h O3 average. The Jarvis-type multiplicative algorithm was used to parametrize gsto including environmental factors i.e. air temperature, light intensity, air vapor pressure deficit, and minimum night-time temperature. Ozone exposure caused a negative impact on AGB, SB and LB. The O3 sensitivity of sugarcane may be related to its high gsto (∼535 mmol H2O m-2 s-1). As sugarcane is adapted to hot climate conditions, gsto was restricted when the current minimum air temperature (Tmin) was below ∼14 °C and the minimum night-time air temperature of the previous day (Tnmin) was below ∼7.5 °C. The flux-based index (PODy) performed better than the exposure-based indices in estimating O3 effect on biomass losses. We recommend a y threshold of 2 nmol m-2 s-1 to incorporate O3 effects on both AGB and SB and 1 nmol m-2 s-1 on LB. In order not to exceed 4% reduction in the growth of these two sugarcane genotypes, we recommend the following critical levels: 1.09 and 1.04 mmol m-2 POD2 for AGB, 0.91 and 0.96 mmol m-2 POD2 for SB, and 3.00 and 2.36 mmol m-2 POD1 for LB of IACSP95-5000 and IACSP94-2094, respectively.

Increased heat transfer to a cylindrical leading edge due to spanwise variations in the freestream velocity

NASA Technical Reports Server (NTRS)

Rigby, D. L.; Vanfossen, G. J.

1991-01-01

The present study numerically demonstrates how small spanwise variations in velocity upstream of a body can cause relatively large increases in the spanwise-averaged heat transfer to the leading edge. Vorticity introduced by spanwise variations, first decays as it drifts downstream, then amplifies in the stagnation region as a result of vortex stretching. This amplification can cause a periodic array of 3 D structures, similar to horseshoe vortices, to form. The numerical results indicate that, for the given wavelength, there is an amplitude threshold below which a structure does not form. A one-dimensional analysis, to predict the decay of vorticity in the absence of the body, in conjunction with the full numerical results indicated that the threshold is more accurately stated as minimum level of vorticity required in the leading edge region for a structure to form. It is possible, using the one-dimensional analysis, to compute an optimum wavelength in terms of the maximum vorticity reaching the leading edge region for given amplitude. A discussion is presented which relates experimentally observed trends to the trends of the present phenomena.

Australians are not equally protected from industrial air pollution

NASA Astrophysics Data System (ADS)

Dobbie, B.; Green, D.

2015-05-01

Australian air pollution standards are set at national and state levels for a number of chemicals harmful to human health. However, these standards do not need to be met when ad hoc pollution licences are issued by state environment agencies. This situation results in a highly unequal distribution of air pollution between towns and cities, and across the country. This paper examines these pollution regulations through two case studies, specifically considering the ability of the regulatory regime to protect human health from lead and sulphur dioxide pollution in the communities located around smelters. It also considers how the proposed National Clean Air Agreement, once enacted, might serve to reduce this pollution equity problem. Through the case studies we show that there are at least three discrete concerns relating to the current licencing system. They are: non-onerous emission thresholds for polluting industry; temporal averaging thresholds masking emission spikes; and ineffective penalties for breaching licence agreements. In conclusion, we propose a set of new, legally-binding national minimum standards for industrial air pollutants must be developed and enforced, which can only be modified by more (not less) stringent state licence arrangements.

Low authority-threshold control for large flexible structures

NASA Technical Reports Server (NTRS)

Zimmerman, D. C.; Inman, D. J.; Juang, J.-N.

1988-01-01

An improved active control strategy for the vibration control of large flexible structures is presented. A minimum force, low authority-threshold controller is developed to bring a system with or without known external disturbances back into an 'allowable' state manifold over a finite time interval. The concept of a constrained, or allowable feedback form of the controller is introduced that reflects practical hardware implementation concerns. The robustness properties of the control strategy are then assessed. Finally, examples are presented which highlight the key points made within the paper.

Analysis of the instability underlying electrostatic suppression of the Leidenfrost state

NASA Astrophysics Data System (ADS)

Shahriari, Arjang; Das, Soumik; Bahadur, Vaibhav; Bonnecaze, Roger T.

2017-03-01

A liquid droplet on a hot solid can generate enough vapor to prevent its contact on the surface and reduce the rate of heat transfer, the so-called Leidenfrost effect. We show theoretically and experimentally that for a sufficiently high electrostatic potential on the droplet, the formation of the vapor layer is suppressed. The interplay of the destabilizing electrostatic force and stabilizing capillary force and evaporation determines the minimum or threshold voltage to suppress the Leidenfrost effect. Linear stability theory accurately predicts threshold voltages for different size droplets and varying temperatures.

Sensitivity of fish density estimates to standard analytical procedures applied to Great Lakes hydroacoustic data

USGS Publications Warehouse

Kocovsky, Patrick M.; Rudstam, Lars G.; Yule, Daniel L.; Warner, David M.; Schaner, Ted; Pientka, Bernie; Deller, John W.; Waterfield, Holly A.; Witzel, Larry D.; Sullivan, Patrick J.

2013-01-01

Standardized methods of data collection and analysis ensure quality and facilitate comparisons among systems. We evaluated the importance of three recommendations from the Standard Operating Procedure for hydroacoustics in the Laurentian Great Lakes (GLSOP) on density estimates of target species: noise subtraction; setting volume backscattering strength (Sv) thresholds from user-defined minimum target strength (TS) of interest (TS-based Sv threshold); and calculations of an index for multiple targets (Nv index) to identify and remove biased TS values. Eliminating noise had the predictable effect of decreasing density estimates in most lakes. Using the TS-based Sv threshold decreased fish densities in the middle and lower layers in the deepest lakes with abundant invertebrates (e.g., Mysis diluviana). Correcting for biased in situ TS increased measured density up to 86% in the shallower lakes, which had the highest fish densities. The current recommendations by the GLSOP significantly influence acoustic density estimates, but the degree of importance is lake dependent. Applying GLSOP recommendations, whether in the Laurentian Great Lakes or elsewhere, will improve our ability to compare results among lakes. We recommend further development of standards, including minimum TS and analytical cell size, for reducing the effect of biased in situ TS on density estimates.

Electrofishing for crappies: Electrical settings influence immobilization efficiency, injury, and mortality

USGS Publications Warehouse

Dolan, C.R.; Miranda, L.E.; Henry, T.B.

2002-01-01

Continuous direct current (DC) and pulsed DC (PDC) of varying frequency and pulse period are commonly used to immobilize and collect crappies Pomoxis spp. in freshwater. However, little information is available about the minimum electrical-setting thresholds required for immobilization or how the settings relate to incidence of injury. We investigated the effect of increasing power densities on the immobilization and injury of black crappies P. nigromaculatus (average total length = 154 mm) treated with DC and various PDC settings. Forced swimming toward the electrodes was observed in black crappies exposed to DC, but that was less apparent for PDC. The minimum peak power densities required to immobilize black crappies ranged from 0.10 to 6.5 mW/cm3 and depended on pulse frequency and period. The incidence of hemorrhaging ranged from 0% to 50% and that of spinal damage from 9% to 45%. However, the severity of injury also depended on pulse frequency and period. No fish suffered mortality at or below the immobilization thresholds, but mortality ranged from 0% to 15% at settings above the thresholds. Mortality was observed with PDC settings of 15 Hz only. Fish that were tetanized following electrical treatment were more prone to injury than those that exhibited narcosis.

Prediction of pKa Values for Neutral and Basic Drugs based on Hybrid Artificial Intelligence Methods.

PubMed

Li, Mengshan; Zhang, Huaijing; Chen, Bingsheng; Wu, Yan; Guan, Lixin

2018-03-05

The pKa value of drugs is an important parameter in drug design and pharmacology. In this paper, an improved particle swarm optimization (PSO) algorithm was proposed based on the population entropy diversity. In the improved algorithm, when the population entropy was higher than the set maximum threshold, the convergence strategy was adopted; when the population entropy was lower than the set minimum threshold the divergence strategy was adopted; when the population entropy was between the maximum and minimum threshold, the self-adaptive adjustment strategy was maintained. The improved PSO algorithm was applied in the training of radial basis function artificial neural network (RBF ANN) model and the selection of molecular descriptors. A quantitative structure-activity relationship model based on RBF ANN trained by the improved PSO algorithm was proposed to predict the pKa values of 74 kinds of neutral and basic drugs and then validated by another database containing 20 molecules. The validation results showed that the model had a good prediction performance. The absolute average relative error, root mean square error, and squared correlation coefficient were 0.3105, 0.0411, and 0.9685, respectively. The model can be used as a reference for exploring other quantitative structure-activity relationships.

An extensive investigation of work function modulated trapezoidal recessed channel MOSFET

NASA Astrophysics Data System (ADS)

Lenka, Annada Shankar; Mishra, Sikha; Mishra, Satyaranjan; Bhanja, Urmila; Mishra, Guru Prasad

2017-11-01

The concept of silicon on insulator (SOI) and grooved gate help to lessen the short channel effects (SCEs). Again the work function modulation along the metal gate gives a better drain current due to the uniform electric field along the channel. So all these concepts are combined and used in the proposed MOSFET structure for more improved performance. In this work, trapezoidal recessed channel silicon on insulator (TRC-SOI) MOSFET and work function modulated trapezoidal recessed channel silicon on insulator (WFM-TRC-SOI) MOSFET are compared with DC and RF parameters and later linearity of both the devices is tested. An analytical model is formulated by using a 2-D Poisson's equation and develops a compact equation for threshold voltage using minimum surface potential. In this work we analyze the effect of negative junction depth and the corner angle on various device parameters such as minimum surface potential, sub-threshold slope (SS), drain induced barrier lowering (DIBL) and threshold voltage. The analysis interprets that the switching performance of WFM-TRC-SOI MOSFET surpasses TRC-SOI MOSFET in terms of high Ion/Ioff ratio and also the proposed structure can minimize the short channel effects (SCEs) in RF application. The validity of proposed model has been verified with simulation result performed on Sentaurus TCAD device simulator.

Color Discrimination Is Affected by Modulation of Luminance Noise in Pseudoisochromatic Stimuli

PubMed Central

Cormenzana Méndez, Iñaki; Martín, Andrés; Charmichael, Teaire L.; Jacob, Mellina M.; Lacerda, Eliza M. C. B.; Gomes, Bruno D.; Fitzgerald, Malinda E. C.; Ventura, Dora F.; Silveira, Luiz C. L.; O'Donell, Beatriz M.; Souza, Givago S.

2016-01-01

Pseudoisochromatic stimuli have been widely used to evaluate color discrimination and to identify color vision deficits. Luminance noise is one of the stimulus parameters used to ensure that subject's response is due to their ability to discriminate target stimulus from the background based solely on the hue between the colors that compose such stimuli. We studied the influence of contrast modulation of the stimulus luminance noise on threshold and reaction time color discrimination. We evaluated color discrimination thresholds using the Cambridge Color Test (CCT) at six different stimulus mean luminances. Each mean luminance condition was tested using two protocols: constant absolute difference between maximum and minimum luminance of the luminance noise (constant delta protocol, CDP), and constant contrast modulation of the luminance noise (constant contrast protocol, CCP). MacAdam ellipses were fitted to the color discrimination thresholds in the CIE 1976 color space to quantify the color discrimination ellipses at threshold level. The same CDP and CCP protocols were applied in the experiment measuring RTs at three levels of stimulus mean luminance. The color threshold measurements show that for the CDP, ellipse areas decreased as a function of the mean luminance and they were significantly larger at the two lowest mean luminances, 10 cd/m2 and 13 cd/m2, compared to the highest one, 25 cd/m2. For the CCP, the ellipses areas also decreased as a function of the mean luminance, but there was no significant difference between ellipses areas estimated at six stimulus mean luminances. The exponent of the decrease of ellipse areas as a function of stimulus mean luminance was steeper in the CDP than CCP. Further, reaction time increased linearly with the reciprocal of the length of the chromatic vectors varying along the four chromatic half-axes. It decreased as a function of stimulus mean luminance in the CDP but not in the CCP. The findings indicated that visual performance using pseudoisochromatic stimuli was dependent on the Weber's contrast of the luminance noise. Low Weber's contrast in the luminance noise is suggested to have a reduced effect on chromatic information and, hence, facilitate desegregation of the hue-defined target from the background. PMID:27458404

Level of visual acuity necessary to avoid false-positives on the HRR and Ishihara color vision tests.

PubMed

Ng, Jason S; Shih, Brian

2017-05-11

Minimizing false-positives (FPs) when evaluating color vision is important in eye care. Identification of plate 1 (demonstration plate) is often considered a way to avoid FPs. However, few studies have quantified the minimum level of visual acuity (VA) that would minimize FPs for the Ishihara and HRR color tests. Threshold levels of optical defocus were obtained from 25 color normal subjects. Blur levels were obtained for Ishihara (38 plate) plates 1, 10, and 15 and 4th edition HRR plates 1, 7, 10, and 20 using the method of limits. Corresponding VAs were measured through these blur levels at 40 centimeters after adjusting for the dioptric distance difference. Analysis of variance testing was used to analyze the data. Mean optical defocus values in diopters (mean ± SD) for HRR plates 1, 7, 10, and 20 were 6.23 ± 1.61, 1.23 ± 1.16, 2.41 ± 1.31, and 7.96 ± 2.03, respectively, and for Ishihara plates 1, 10, and 15 were 5.70 ± 1.52, 3.68 ± 1.71, and 4.62 ± 1.56, respectively. There was a significant difference between the screening and demonstration plates for both tests (p<0.001). Based on the plate in each test that was found to be the least tolerant to blur, the average minimum VAs needed to identify the screening plates were approximately 20/180 for the Ishihara test and 20/50 for the HRR test. Identifying the demonstration plate in the Ishihara and HRR tests does not ensure FPs will be avoided.

Hearing Threshold, Loss, Noise Levels and Worker’s Profiles of an Open Cast Chromite Mines in Odisha, India

PubMed Central

Kerketta, Sunamani; Gartia, Rajendra; Bagh, Somanath

2012-01-01

Objectives: The aims of the study were to describe the noise levels at an open cast chromite mine in Odisha, India, and the hearing threshold of its workers and to associate their hearing loss with their age, work station and length of employment at the mine. Methods: We performed a cross-sectional study of the hearing threshold of chromite mine workers. Audiometric data from 500 subjects was collected at the mines’ hospital in the Sukinda Valley of Jajpur, Odisha, India. The latest audiometry data available for the period 2002 to 2008 was used in the analysis. Audiometric screening was performed using an audiometer (TRIVENI TAM-25 6025A) in a quiet environment by qualified technicians, audiologists or physicians. Tests were conducted on the subjects after they had completely rested for 16 hours or more after their day shift. Results: A maximum of 262 subjects (52.4%) were employed in the work zone area and a minimum of 2 subjects (0.4%) had less than 5 years working experience. The age of the subjects ranged from 29 to 59 years and their working experience ranged from 4 to 37 years. The subjects’ average mean hearing thresholds at 4, 6 and 8 kHz were 21.53 dBA, 23.40 dBA and 21.90 dBA, respectively. The maximum Leq and L90 levels exceeded the prescribed limits for commercial, residential and silence zones. The maximum Leq levels exceeded 95 dBA for large and medium heavy earth moving machineries (HEMMs), both outside and at the operator’s position. Hearing loss due to the subjects’ work experience was found to be greater than that attributable to age and workstation. Conclusion: In our study population, the maximum noise levels for large and medium HEMMs and inside the cabins of HEMMs were found to be more than 95 dBA. This indicates that operators in this particular chromite mine at Odisha, India were exposed to noise levels exceeding 95 dBA for more than 10% of the monitoring time. The subjects’ hearing loss was also found to increase for every 10-year age interval and that for every 5 years of work experience at high fence. The subjects’ age and experience are significantly associated with hearing loss at all levels for frequencies of 4.0, 6.0, and 8.0 kHz, with older and more experienced workers having a higher incidence of hearing loss. PMID:23613650

Hearing Threshold, Loss, Noise Levels and Worker's Profiles of an Open Cast Chromite Mines in Odisha, India.

PubMed

Kerketta, Sunamani; Gartia, Rajendra; Bagh, Somanath

2012-10-01

The aims of the study were to describe the noise levels at an open cast chromite mine in Odisha, India, and the hearing threshold of its workers and to associate their hearing loss with their age, work station and length of employment at the mine. We performed a cross-sectional study of the hearing threshold of chromite mine workers. Audiometric data from 500 subjects was collected at the mines' hospital in the Sukinda Valley of Jajpur, Odisha, India. The latest audiometry data available for the period 2002 to 2008 was used in the analysis. Audiometric screening was performed using an audiometer (TRIVENI TAM-25 6025A) in a quiet environment by qualified technicians, audiologists or physicians. Tests were conducted on the subjects after they had completely rested for 16 hours or more after their day shift. A maximum of 262 subjects (52.4%) were employed in the work zone area and a minimum of 2 subjects (0.4%) had less than 5 years working experience. The age of the subjects ranged from 29 to 59 years and their working experience ranged from 4 to 37 years. The subjects' average mean hearing thresholds at 4, 6 and 8 kHz were 21.53 dBA, 23.40 dBA and 21.90 dBA, respectively. The maximum Leq and L90 levels exceeded the prescribed limits for commercial, residential and silence zones. The maximum Leq levels exceeded 95 dBA for large and medium heavy earth moving machineries (HEMMs), both outside and at the operator's position. Hearing loss due to the subjects' work experience was found to be greater than that attributable to age and workstation. In our study population, the maximum noise levels for large and medium HEMMs and inside the cabins of HEMMs were found to be more than 95 dBA. This indicates that operators in this particular chromite mine at Odisha, India were exposed to noise levels exceeding 95 dBA for more than 10% of the monitoring time. The subjects' hearing loss was also found to increase for every 10-year age interval and that for every 5 years of work experience at high fence. The subjects' age and experience are significantly associated with hearing loss at all levels for frequencies of 4.0, 6.0, and 8.0 kHz, with older and more experienced workers having a higher incidence of hearing loss.

Potential of solar-simulator-pumped alexandrite lasers

NASA Technical Reports Server (NTRS)

Deyoung, Russell J.

1990-01-01

An attempt was made to pump an alexandrite laser rod using a Tamarak solar simulator and also a tungsten-halogen lamp. A very low optical laser cavity was used to achieve the threshold minimum pumping-power requirement. Lasing was not achieved. The laser threshold optical-power requirement was calculated to be approximately 626 W/sq cm for a gain length of 7.6 cm, whereas the Tamarak simulator produces 1150 W/sq cm over a gain length of 3.3 cm, which is less than the 1442 W/sq cm required to reach laser threshold. The rod was optically pulsed with 200 msec pulses, which allowed the alexandrite rod to operate at near room temperature. The optical intensity-gain-length product to achieve laser threshold should be approximately 35,244 solar constants-cm. In the present setup, this product was 28,111 solar constants-cm.

A Minimum (Delta)V Orbit Maintenance Strategy for Low-Altitude Missions Using Burn Parameter Optimization

NASA Technical Reports Server (NTRS)

Brown, Aaron J.

2011-01-01

Orbit maintenance is the series of burns performed during a mission to ensure the orbit satisfies mission constraints. Low-altitude missions often require non-trivial orbit maintenance (Delta)V due to sizable orbital perturbations and minimum altitude thresholds. A strategy is presented for minimizing this (Delta)V using impulsive burn parameter optimization. An initial estimate for the burn parameters is generated by considering a feasible solution to the orbit maintenance problem. An example demonstrates the dV savings from the feasible solution to the optimal solution.

TOPICAL REVIEW: The shallow-to-deep instability of hydrogen and muonium in II VI and III V semiconductors

NASA Astrophysics Data System (ADS)

Cox, S. F. J.

2003-11-01

The structure and electrical activity of monatomic hydrogen defect centres are inferred from the spectroscopy and charge-state transitions of muonium, the light pseudo-isotope of hydrogen. Introductions are given to all these topics. Special attention is paid to the shallow-donor behaviour recently established in a number of II VI compounds and one III nitride. This contrasts with trapped-atom states suggestive of an acceptor function in other members of the II VI family as well as with the deep-level amphoteric behaviour which has long been known in the elemental group-IV semiconductors and certain III V compounds. The systematics of this remarkable shallow-to-deep instability are examined in terms of simple chemical considerations, as well as current theoretical and computational models. The muonium data appear to confirm predictions that the switch from shallow to deep behaviour is governed primarily by the depth of the conduction-band minimum below the vacuum continuum. The threshold electron affinity is around 3.5 eV, which compares favourably with computational estimates of a so-called pinning level for hydrogen (+/-) charge-state transitions of between -3 and -4.5 eV. A purely ionic model gives some intuitive understanding of this behaviour as well as the invariance of the threshold. Another current description applies equally to covalent materials and relates the threshold to the origin of the electrochemical scale. At the present level of approximation, zero-point energy corrections to the transition levels are small, so that muonium data should provide a reliable guide to the behaviour of hydrogen. Muonium spectroscopy proves to be more sensitive to the (0/+) donor level than to the (+/-) pinning level but, as a tool which does not rely on favourable hydrogen solubility, it looks set to test further predictions of these models in a large number of other materials, notably oxides. Certain candidate thin-film insulators and high-permittivity gate dielectrics appear to be uncomfortably close to conditions in which hydrogen impurity may cause electronic conduction.

50 CFR 600.315 - National Standard 2-Scientific Information.

Code of Federal Regulations, 2010 CFR

2010-10-01

... sources to improve understanding and management of the resource, marine ecosystem, and the fishery... any stock or stock complex is approaching the minimum stock size threshold. (ii) Any management..., social, and ecological information pertinent to the success of management or the achievement of...

50 CFR 600.315 - National Standard 2-Scientific Information.

Code of Federal Regulations, 2011 CFR

2011-10-01

... sources to improve understanding and management of the resource, marine ecosystem, and the fishery... any stock or stock complex is approaching the minimum stock size threshold. (ii) Any management..., social, and ecological information pertinent to the success of management or the achievement of...

Multiple addresses: 201 S. LSD and 401 N. LSD, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements beneath the removed pavement and within the excavated areas of theproject did not exceed the instrument threshold previously stated, and ranged from a minimum of 700cpm to a maximum of 4,500 cpm shielded.

615-640 N. Michigan Ave. and 101-155 E. Ontario, January 2018, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements for the spoil and within the remaining excavations did not exceed the instrument threshold previously stated, and ranged from a minimum of 1,400 cpm to a maximum of 4,000 cpm shielded.

Multiple addresses: 500-59 E. Illinois St. and 500-91 E. Grand Ave., Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation during the excavation process did not exceed theinstrument threshold previously stated, and ranged from a minimum of 1,200 cpm to a maximum of 3,100cpm shielded.

Identification and Purification of Nyalo River Silica Sand as Raw Material for the Synthesis of Sodium Silicate

NASA Astrophysics Data System (ADS)

Aini, S.; Nizar, U. K.; NST, A. Amelia; Efendi, J.

2018-04-01

This research is on identification and purification of silica sand from Nyalo River. It will be used as a raw material for synthesis of sodium silicate. Silica sand was separated from clay by washing it with water, and then the existing alumina and iron oxide were removed by soaking the silica sand with 1 M HNO3 solution. Qualitative and quantitative analysis of the silica sand with X-ray diffraction and X-ray fluorescence revealed that, silica sand existed in quartz form and contained a small amount of impurity oxide such as Al2O3, K2O, MgO, CaO, Fe2O3 with percentage below the minimum threshold. The percentages of silica were 80.59% before purification. After three purificationsteps the silica percentage become 98.38%. It exceedsthe minimum threshold of silica percentage for industry.So, the silica sand from Nyalo River has high potency as a raw material for sodium silicate synthesizing.

Minimum Transendothelial Electrical Resistance Thresholds for the Study of Small and Large Molecule Drug Transport in a Human in Vitro Blood-Brain Barrier Model.

PubMed

Mantle, Jennifer L; Min, Lie; Lee, Kelvin H

2016-12-05

A human cell-based in vitro model that can accurately predict drug penetration into the brain as well as metrics to assess these in vitro models are valuable for the development of new therapeutics. Here, human induced pluripotent stem cells (hPSCs) are differentiated into a polarized monolayer that express blood-brain barrier (BBB)-specific proteins and have transendothelial electrical resistance (TEER) values greater than 2500 Ω·cm 2 . By assessing the permeabilities of several known drugs, a benchmarking system to evaluate brain permeability of drugs was established. Furthermore, relationships between TEER and permeability to both small and large molecules were established, demonstrating that different minimum TEER thresholds must be achieved to study the brain transport of these two classes of drugs. This work demonstrates that this hPSC-derived BBB model exhibits an in vivo-like phenotype, and the benchmarks established here are useful for assessing functionality of other in vitro BBB models.

Approximate Solutions for a Self-Folding Problem of Carbon Nanotubes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Y Mikata

2006-08-22

This paper treats approximate solutions for a self-folding problem of carbon nanotubes. It has been observed in the molecular dynamics calculations [1] that a carbon nanotube with a large aspect ratio can self-fold due to van der Waals force between the parts of the same carbon nanotube. The main issue in the self-folding problem is to determine the minimum threshold length of the carbon nanotube at which it becomes possible for the carbon nanotube to self-fold due to the van der Waals force. An approximate mathematical model based on the force method is constructed for the self-folding problem of carbonmore » nanotubes, and it is solved exactly as an elastica problem using elliptic functions. Additionally, three other mathematical models are constructed based on the energy method. As a particular example, the lower and upper estimates for the critical threshold (minimum) length are determined based on both methods for the (5,5) armchair carbon nanotube.« less

49 CFR 387.33 - Financial responsibility, minimum levels.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 5 2010-10-01 2010-10-01 false Financial responsibility, minimum levels. 387.33... MINIMUM LEVELS OF FINANCIAL RESPONSIBILITY FOR MOTOR CARRIERS Motor Carriers of Passengers § 387.33 Financial responsibility, minimum levels. The minimum levels of financial responsibility referred to in...

Controlling marginally detached divertor plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eldon, David; Kolemen, Egemen; Barton, Joseph L.

A new control system at DIII-D has stabilized the inter-ELM detached divertor plasma state for H-mode in close proximity to the threshold for reattachment, thus demonstrating the ability to maintain detachment with minimal gas puffing. When the same control system was instead ordered to hold the plasma at the threshold (here defined as T e = 5 eV near the divertor target plate), the resulting T e profiles separated into two groups with one group consistent with marginal detachment, and the other with marginal attachment. The plasma dithers between the attached and detached states when the control system attempts to hold at the threshold. The control system is upgraded from the one described in and it handles ELMing plasmas by using real time D α measurements to remove during-ELM slices from real time T e measurements derived from divertor Thomson scattering. The difference between measured and requested inter-ELM T e is passed to a PID (proportionalintegral-derivative) controller to determine gas puff commands. While some degree of detachment is essential for the health of ITER’s divertor, more deeply detached plasmas have greater radiative losses and, at the extreme, confinement degradation, making it desirable to limit detachment to the minimum level needed to protect the target plate. However, the observed bifurcation in plasma conditions at the outer strike point with the ion B ×more » $$\

Controlling marginally detached divertor plasmas

DOE PAGES

Eldon, David; Kolemen, Egemen; Barton, Joseph L.; ...

2017-05-04

A new control system at DIII-D has stabilized the inter-ELM detached divertor plasma state for H-mode in close proximity to the threshold for reattachment, thus demonstrating the ability to maintain detachment with minimal gas puffing. When the same control system was instead ordered to hold the plasma at the threshold (here defined as T e = 5 eV near the divertor target plate), the resulting T e profiles separated into two groups with one group consistent with marginal detachment, and the other with marginal attachment. The plasma dithers between the attached and detached states when the control system attempts to hold at the threshold. The control system is upgraded from the one described in and it handles ELMing plasmas by using real time D α measurements to remove during-ELM slices from real time T e measurements derived from divertor Thomson scattering. The difference between measured and requested inter-ELM T e is passed to a PID (proportionalintegral-derivative) controller to determine gas puff commands. While some degree of detachment is essential for the health of ITER’s divertor, more deeply detached plasmas have greater radiative losses and, at the extreme, confinement degradation, making it desirable to limit detachment to the minimum level needed to protect the target plate. However, the observed bifurcation in plasma conditions at the outer strike point with the ion B ×more » $$\

[Physical medicine in hospital. Minimum standards in a physical medical department in acute inpatient areas in rheumatology].

PubMed

Reißhauer, A; Liebl, M E

2012-07-01

Standards for what should be available in terms of equipment and services in a department of physical medicine caring for acute inpatients do not exist in Germany. The profile of a department determines the therapeutic services it focuses on and hence the technical facilities required. The German catalogue of operations and procedures defines minimum thresholds for treatment. In the opinion of the authors a department caring for inpatients with acute rheumatic diseases must, as a minimum, have the facilities and equipment necessary for offering thermotherapeutic treatment. Staff trained in physical therapeutic procedures and occupational therapy is also crucial. Moreover, it is desirable that the staff should be trained in manual therapy.

Bounds of cavitation inception in a creeping flow between eccentric cylinders rotating with a small minimum gap

NASA Astrophysics Data System (ADS)

Monakhov, A. A.; Chernyavski, V. M.; Shtemler, Yu.

2013-09-01

Bounds of cavitation inception are experimentally determined in a creeping flow between eccentric cylinders, the inner one being static and the outer rotating at a constant angular velocity, Ω. The geometric configuration is additionally specified by a small minimum gap between cylinders, H, as compared with the radii of the inner and outer cylinders. For some values H and Ω, cavitation bubbles are observed, which are collected on the surface of the inner cylinder and equally distributed over the line parallel to its axis near the downstream minimum gap position. Cavitation occurs for the parameters {H,Ω} within a region bounded on the right by the cavitation inception curve that passes through the plane origin and cannot exceed the asymptotic threshold value of the minimum gap, Ha, in whose vicinity cavitation may occur at H < Ha only for high angular rotation velocities.

On the impacts of computing daily temperatures as the average of the daily minimum and maximum temperatures

NASA Astrophysics Data System (ADS)

Villarini, Gabriele; Khouakhi, Abdou; Cunningham, Evan

2017-12-01

Daily temperature values are generally computed as the average of the daily minimum and maximum observations, which can lead to biases in the estimation of daily averaged values. This study examines the impacts of these biases on the calculation of climatology and trends in temperature extremes at 409 sites in North America with at least 25 years of complete hourly records. Our results show that the calculation of daily temperature based on the average of minimum and maximum daily readings leads to an overestimation of the daily values of 10+ % when focusing on extremes and values above (below) high (low) thresholds. Moreover, the effects of the data processing method on trend estimation are generally small, even though the use of the daily minimum and maximum readings reduces the power of trend detection ( 5-10% fewer trends detected in comparison with the reference data).

49 CFR 387.9 - Financial responsibility, minimum levels.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 5 2010-10-01 2010-10-01 false Financial responsibility, minimum levels. 387.9... MINIMUM LEVELS OF FINANCIAL RESPONSIBILITY FOR MOTOR CARRIERS Motor Carriers of Property § 387.9 Financial responsibility, minimum levels. The minimum levels of financial responsibility referred to in § 387.7 of this...

Contribution of piezometric measurement to knowledge and management of low water levels: examples on the chalk aquifer in the Champagne Ardennes region

NASA Astrophysics Data System (ADS)

Stollsteiner, P.; Bessiere, H.; Nicolas, J.; Allier, D.; Berthet, O.

2015-04-01

This article is based on a BRGM study on piezometric indicators, threshold values of discharge and groundwater levels for the assessment of potentially-exploitable water resources of chalky watersheds. A method for estimating low water levels based on groundwater levels is presented from three examples representing chalk aquifers with different cycles: annual, combined and interannual. The first is located in Picardy and the two others in the Champagne-Ardennes region. Piezometers with annual cycles, used in these examples, are supposed to be representative of the aquifer hydro-dynamics. Except for multi-annual systems, the analysis between discharge measurements at a hydrometric station and groundwater levels measured at a piezometer representative of the main aquifer, leads to relatively precise and satisfactory relationships within a chalky context. These relationships may be useful for monitoring, validation, extension or reconstruction of the low water flow data. On the one hand, they allow definition of the piezometric levels corresponding to the different alert thresholds of river discharges. On the other hand, they clarify the proportions of low surface water flow from runoff or drainage of the aquifer. Finally, these correlations give an assessment of the minimum flow for the coming weeks. However, these correlations cannot be used to optimize the value of the exploitable water resource because it seems to be difficult to integrate the value of the effective rainfall that could occur during the draining period. Moreover, in the case of multi-annual systems, the solution is to attempt a comprehensive system modelling and, if it is satisfactory, using the simulated values to get rid of parasites or running the model for forecasting purposes.

Sub-parts-per-billion level detection of dimethyl methyl phosphonate (DMMP) by quantum cascade laser photoacoustic spectroscopy.

PubMed

Mukherjee, Anadi; Dunayevskiy, Ilya; Prasanna, Manu; Go, Rowel; Tsekoun, Alexei; Wang, Xiaojun; Fan, Jenyu; Patel, C Kumar N

2008-04-01

The need for the detection of chemical warfare agents (CWAs) is no longer confined to battlefield environments because of at least one confirmed terrorist attack, the Tokyo Subway [Emerg. Infect. Dis. 5, 513 (1999)] in 1995, and a suspected, i.e., a false-alarm of a CWA in the Russell Senate Office Building [Washington Post, 9 February 2006, p. B01]. Therefore, detection of CWAs with high sensitivity and low false-alarm rates is considered an important priority for ensuring public safety. We report a minimum detection level for a CWA simulant, dimethyl methyl phosphonate (DMMP), of <0.5 ppb (parts in 10(9)) by use of a widely tunable external grating cavity quantum cascade laser and photoacoustic spectroscopy. With interferents present in Santa Monica, California street air, we demonstrate a false-alarm rate of 1:10(6) at a detection threshold of 1.6 ppb.

Minimum duration of actigraphy-defined nocturnal awakenings necessary for morning recall.

PubMed

Winser, Michael A; McBean, Amanda L; Montgomery-Downs, Hawley E

2013-07-01

Healthy adults awaken between each sleep cycle approximately 5 times each night but generally do not remember all of these awakenings in the morning. A rule of thumb has arisen in the sleep field that approximately 5 min of continuous wakefulness are required to form a memory for an awakening. However, few studies have examined memory for these sleep-wake transitions and none have done so in the home, while participants follow their normal routine. Self-report and actigraphy were used in the participant's home environment to determine the minimum duration of an awakening necessary for morning recall for each of the 39 healthy adults. Recall thresholds ranged from 30 to 600 s with a mean of 259 s (4 min 19 s) and were negatively associated with sleep efficiency but not significantly associated with total sleep time, age, income, or education. There also was a sex by cohabitation interaction, with single men having lower thresholds than single women and cohabiting participants, which was explained by higher sleep efficiency in noncohabitating men. Large individual differences suggest that many factors may influence recall threshold. Our preliminary study is the first to calculate the duration of wakefulness necessary for morning recall of nocturnal awakenings and the first to use a field-based design, allowing for the study of habitual sleep patterns at the participant's home. Further study is needed to explore if recall thresholds calculated using actigraphy can be validated against polysomnography (PSG) or be used to guide potential treatments. Copyright © 2013 Elsevier B.V. All rights reserved.

Cortical neuron activation induced by electromagnetic stimulation: a quantitative analysis via modelling and simulation.

PubMed

Wu, Tiecheng; Fan, Jie; Lee, Kim Seng; Li, Xiaoping

2016-02-01

Previous simulation works concerned with the mechanism of non-invasive neuromodulation has isolated many of the factors that can influence stimulation potency, but an inclusive account of the interplay between these factors on realistic neurons is still lacking. To give a comprehensive investigation on the stimulation-evoked neuronal activation, we developed a simulation scheme which incorporates highly detailed physiological and morphological properties of pyramidal cells. The model was implemented on a multitude of neurons; their thresholds and corresponding activation points with respect to various field directions and pulse waveforms were recorded. The results showed that the simulated thresholds had a minor anisotropy and reached minimum when the field direction was parallel to the dendritic-somatic axis; the layer 5 pyramidal cells always had lower thresholds but substantial variances were also observed within layers; reducing pulse length could magnify the threshold values as well as the variance; tortuosity and arborization of axonal segments could obstruct action potential initiation. The dependence of the initiation sites on both the orientation and the duration of the stimulus implies that the cellular excitability might represent the result of the competition between various firing-capable axonal components, each with a unique susceptibility determined by the local geometry. Moreover, the measurements obtained in simulation intimately resemble recordings in physiological and clinical studies, which seems to suggest that, with minimum simplification of the neuron model, the cable theory-based simulation approach can have sufficient verisimilitude to give quantitatively accurate evaluation of cell activities in response to the externally applied field.

21 CFR 886.1050 - Adaptometer (biophotometer).

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Adaptometer (biophotometer). 886.1050 Section 886.1050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... (regeneration of the visual purple) and the minimum light threshold. (b) Classification. Class I (general...

Issues with fruit dietary supplements in the US - authentication by anthocyanin

USDA-ARS?s Scientific Manuscript database

Current fruit-based dietary supplements in the US marketplace have no obligation to meet any fruit-component concentration requirement. For example, berry supplements might be promoted for their high anthocyanin content, but they actually have no standard or minimum anthocyanin threshold for legal s...

150-211 E. Illinois St and 450-51 N St. Clair Streets, February 2018, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation during the excavation process did not exceed the instrument threshold previously stated and ranged from a minimum of 1,100 cpm to a maximum of 2,100cpm shielded.

International business cycle synchronization since the 1870s: Evidence from a novel network approach

NASA Astrophysics Data System (ADS)

Antonakakis, Nikolaos; Gogas, Periklis; Papadimitriou, Theophilos; Sarantitis, Georgios Antonios

2016-04-01

In this study, we examine the issue of business cycle synchronization from a historical perspective in 27 developed and developing countries. Based on a novel complex network approach, the Threshold-Minimum Dominating Set (T-MDS), our results reveal heterogeneous patterns of international business cycle synchronization during fundamental globalization periods since the 1870s. In particular, the proposed methodology reveals that worldwide business cycles de-coupled during the Gold Standard, though they were synchronized during the Great Depression. The Bretton Woods era was associated with a lower degree of synchronization as compared to that during the Great Depression, while worldwide business cycle synchronization increased to unprecedented levels during the latest period of floating exchange rates and the Great Recession.

Ambient high temperature and mortality in Jinan, China: A study of heat thresholds and vulnerable populations.

PubMed

Li, Jing; Xu, Xin; Yang, Jun; Liu, Zhidong; Xu, Lei; Gao, Jinghong; Liu, Xiaobo; Wu, Haixia; Wang, Jun; Yu, Jieqiong; Jiang, Baofa; Liu, Qiyong

2017-07-01

Understanding the health consequences of continuously rising temperatures-as is projected for China-is important in terms of developing heat-health adaptation and intervention programs. This study aimed to examine the association between mortality and daily maximum (T max ), mean (T mean ), and minimum (T min ) temperatures in warmer months; to explore threshold temperatures; and to identify optimal heat indicators and vulnerable populations. Daily data on temperature and mortality were obtained for the period 2007-2013. Heat thresholds for condition-specific mortality were estimated using an observed/expected analysis. We used a generalised additive model with a quasi-Poisson distribution to examine the association between mortality and T max /T min /T mean values higher than the threshold values, after adjustment for covariates. T max /T mean /T min thresholds were 32/28/24°C for non-accidental deaths; 32/28/24°C for cardiovascular deaths; 35/31/26°C for respiratory deaths; and 34/31/28°C for diabetes-related deaths. For each 1°C increase in T max /T mean /T min above the threshold, the mortality risk of non-accidental-, cardiovascular-, respiratory, and diabetes-related death increased by 2.8/5.3/4.8%, 4.1/7.2/6.6%, 6.6/25.3/14.7%, and 13.3/30.5/47.6%, respectively. Thresholds for mortality differed according to health condition when stratified by sex, age, and education level. For non-accidental deaths, effects were significant in individuals aged ≥65 years (relative risk=1.038, 95% confidence interval: 1.026-1.050), but not for those ≤64 years. For most outcomes, women and people ≥65 years were more vulnerable. High temperature significantly increases the risk of mortality in the population of Jinan, China. Climate change with rising temperatures may bring about the situation worse. Public health programs should be improved and implemented to prevent and reduce health risks during hot days, especially for the identified vulnerable groups. Copyright © 2017. Published by Elsevier Inc.

Experimental investigations of the minimum ignition energy and the minimum ignition temperature of inert and combustible dust cloud mixtures.

PubMed

Addai, Emmanuel Kwasi; Gabel, Dieter; Krause, Ulrich

2016-04-15

The risks associated with dust explosions still exist in industries that either process or handle combustible dust. This explosion risk could be prevented or mitigated by applying the principle of inherent safety (moderation). This is achieved by adding an inert material to a highly combustible material in order to decrease the ignition sensitivity of the combustible dust. The presented paper deals with the experimental investigation of the influence of adding an inert dust on the minimum ignition energy and the minimum ignition temperature of the combustible/inert dust mixtures. The experimental investigation was done in two laboratory scale equipment: the Hartmann apparatus and the Godbert-Greenwald furnace for the minimum ignition energy and the minimum ignition temperature test respectively. This was achieved by mixing various amounts of three inert materials (magnesium oxide, ammonium sulphate and sand) and six combustible dusts (brown coal, lycopodium, toner, niacin, corn starch and high density polyethylene). Generally, increasing the inert materials concentration increases the minimum ignition energy as well as the minimum ignition temperatures until a threshold is reached where no ignition was obtained. The permissible range for the inert mixture to minimize the ignition risk lies between 60 to 80%. Copyright © 2016 Elsevier B.V. All rights reserved.

Exogenous corticosterone and nest abandonment: a study in a long-lived bird, the Adélie penguin.

PubMed

Spée, Marion; Marchal, Lorène; Lazin, David; Le Maho, Yvon; Chastel, Olivier; Beaulieu, Michaël; Raclot, Thierry

2011-09-01

Breeding individuals enter an emergency life-history stage when their body reserves reach a minimum threshold. Consequently, they redirect current activity toward survival, leading to egg abandonment in birds. Corticosterone (CORT) is known to promote this stage. How and to what extent CORT triggers egg abandonment when breeding is associated with prolonged fasting, however, requires further investigation. We manipulated free-living male Adélie penguins with CORT-pellets before their laying period. We then examined their behavioral response with respect to nest abandonment in parallel with their prolactin levels (regulating parental care), and the subsequent effects of treatment on breeding success in relieved birds. Exogenous CORT triggered nest abandonment in 60% of the treated penguins ~14 days after treatment and induced a concomitant decline in prolactin levels. Interestingly, prolactin levels in treated penguins that did not abandon their nest were higher at the point of implantation and also after being relieved by females, when compared with abandoning penguins. Among successful birds, the treatment did not affect the number of chicks, nor the brood mass. Our results show the involvement of CORT in the decision-making process regarding egg abandonment in Adélie penguins when incubation is associated with a natural long fast. However, we suggest that CORT alone is not sufficient to trigger nest abandonment but that 1) prolactin levels need to reach a low threshold value, and 2) a rise in proteolysis (i.e. utilization of protein as main energy substrate) seems also to be required. Copyright © 2011 Elsevier Inc. All rights reserved.

[Minimum Standards for the Spatial Accessibility of Primary Care: A Systematic Review].

PubMed

Voigtländer, S; Deiters, T

2015-12-01

Regional disparities of access to primary care are substantial in Germany, especially in terms of spatial accessibility. However, there is no legally or generally binding minimum standard for the spatial accessibility effort that is still acceptable. Our objective is to analyse existing minimum standards, the methods used as well as their empirical basis. A systematic literature review was undertaken of publications regarding minimum standards for the spatial accessibility of primary care based on a title word and keyword search using PubMed, SSCI/Web of Science, EMBASE and Cochrane Library. 8 minimum standards from the USA, Germany and Austria could be identified. All of them specify the acceptable spatial accessibility effort in terms of travel time; almost half include also distance(s). The travel time maximum, which is acceptable, is 30 min and it tends to be lower in urban areas. Primary care is, according to the identified minimum standards, part of the local area (Nahbereich) of so-called central places (Zentrale Orte) providing basic goods and services. The consideration of means of transport, e. g. public transport, is heterogeneous. The standards are based on empirical studies, consultation with service providers, practical experiences, and regional planning/central place theory as well as on legal or political regulations. The identified minimum standards provide important insights into the effort that is still acceptable regarding spatial accessibility, i. e. travel time, distance and means of transport. It seems reasonable to complement the current planning system for outpatient care, which is based on provider-to-population ratios, by a gravity-model method to identify places as well as populations with insufficient spatial accessibility. Due to a lack of a common minimum standard we propose - subject to further discussion - to begin with a threshold based on the spatial accessibility limit of the local area, i. e. 30 min to the next primary care provider for at least 90% of the regional population. The exceeding of the threshold would necessitate a discussion of a health care deficit and in line with this a potential need for intervention, e. g. in terms of alternative forms of health care provision. © Georg Thieme Verlag KG Stuttgart · New York.

Pool desiccation and developmental thresholds in the common frog, Rana temporaria.

PubMed

Lind, Martin I; Persbo, Frida; Johansson, Frank

2008-05-07

The developmental threshold is the minimum size or condition that a developing organism must have reached in order for a life-history transition to occur. Although developmental thresholds have been observed for many organisms, inter-population variation among natural populations has not been examined. Since isolated populations can be subjected to strong divergent selection, population divergence in developmental thresholds can be predicted if environmental conditions favour fast or slow developmental time in different populations. Amphibian metamorphosis is a well-studied life-history transition, and using a common garden approach we compared the development time and the developmental threshold of metamorphosis in four island populations of the common frog Rana temporaria: two populations originating from islands with only temporary breeding pools and two from islands with permanent pools. As predicted, tadpoles from time-constrained temporary pools had a genetically shorter development time than those from permanent pools. Furthermore, the variation in development time among females from temporary pools was low, consistent with the action of selection on rapid development in this environment. However, there were no clear differences in the developmental thresholds between the populations, indicating that the main response to life in a temporary pool is to shorten the development time.

Invasive pathogen threatens bird-pine mutualism: implications for sustaining a high-elevation ecosystem.

PubMed

McKinney, Shawn T; Fiedler, Carl E; Tomback, Diana F

2009-04-01

Human-caused disruptions to seed-dispersal mutualisms increase the extinction risk for both plant and animal species. Large-seeded plants can be particularly vulnerable due to highly specialized dispersal systems and no compensatory regeneration mechanisms. Whitebark pine (Pinus albicaulis), a keystone subalpine species, obligately depends upon the Clark's Nutcracker (Nucifraga columbiana) for dispersal of its large, wingless seeds. Clark's Nutcracker, a facultative mutualist with whitebark pine, is sensitive to rates of energy gain, and emigrates from subalpine forests during periods of cone shortages. The invasive fungal pathogen Cronartium ribicola, which causes white pine blister rust, reduces whitebark pine cone production by killing cone-bearing branches and trees. Mortality from blister rust reaches 90% or higher in some whitebark pine forests in the Northern Rocky Mountains, USA, and the rust now occurs nearly rangewide in whitebark pine. Our objectives were to identify the minimum level of cone production necessary to elicit seed dispersal by nutcrackers and to determine how cone production is influenced by forest structure and health. We quantified forest conditions and ecological interactions between nutcrackers and whitebark pine in three Rocky Mountain ecosystems that differ in levels of rust infection and mortality. Both the frequency of nutcracker occurrence and probability of seed dispersal were strongly related to annual whitebark pine cone production, which had a positive linear association with live whitebark pine basal area, and negative linear association with whitebark pine tree mortality and rust infection. From our data, we estimated that a threshold level of approximately 1000 cones/ha is needed for a high likelihood of seed dispersal by nutcrackers (probability > or = 0.7), and that this level of cone production can be met by forests with live whitebark pine basal area > 5.0 m2/ha. The risk of mutualism disruption is greatest in northern most Montana (USA), where three-year mean cone production and live basal area fell below predicted threshold levels. There, nutcracker occurrence, seed dispersal, and whitebark pine regeneration were the lowest of the three ecosystems. Managers can use these threshold values to differentiate between restoration sites requiring planting of rust-resistant seedlings and sites where nutcracker seed dispersal can be expected.

75 FR 68430 - Domestic Shipping Services Pricing and Mailing Standards Changes

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-08

... has eliminated the requirement for a postal routing barcode when paying postage with permit imprint... minimum volume threshold applies, except the permit imprint requirement of 200 pieces or 50 pounds of mail... permit imprint. Customers using USPS-approved IBI postage meters that print the IBI with the appropriate...

When Benefits Are Difficult to Measure.

ERIC Educational Resources Information Center

Birdsall, William C.

1987-01-01

It is difficult to apply benefit cost analysis to human service programs. This paper explains "threshold benefit analysis," the derivation of the minimum dollar value which the benefits must attain in order for their value to equal the intervention costs. The method is applied to a mobility training program. (BS)

Lake Shore Drive\\\\Grand Ave.\\\\E. Illinois Ave., May 2016, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

Field gamma measurements process did not exceed the instrument threshold. Unshielded readings ranged from a minimumof 4,600 cpm to a maximum of 14,200 cpm unshielded and shielded readings ranged from a minimum of1,800 cpm to 2,680 cpm.

13 CFR 315.7 - Certification requirements.

Code of Federal Regulations, 2013 CFR

2013-01-01

...) Minimum certification thresholds. (1) Twelve-month decline. Based upon a comparison of the most recent 12... percent of the total production or sales of the Firm during the 12-month period preceding the most recent...-month versus twenty-four month decline. Based upon a comparison of the most recent 12-month period for...

13 CFR 315.7 - Certification requirements.

Code of Federal Regulations, 2012 CFR

2012-01-01

...) Minimum certification thresholds. (1) Twelve-month decline. Based upon a comparison of the most recent 12... percent of the total production or sales of the Firm during the 12-month period preceding the most recent...-month versus twenty-four month decline. Based upon a comparison of the most recent 12-month period for...

13 CFR 315.7 - Certification requirements.

Code of Federal Regulations, 2011 CFR

2011-01-01

...) Minimum certification thresholds. (1) Twelve-month decline. Based upon a comparison of the most recent 12... percent of the total production or sales of the Firm during the 12-month period preceding the most recent...-month versus twenty-four month decline. Based upon a comparison of the most recent 12-month period for...

13 CFR 315.7 - Certification requirements.

Code of Federal Regulations, 2014 CFR

2014-01-01

...) Minimum certification thresholds. (1) Twelve-month decline. Based upon a comparison of the most recent 12... percent of the total production or sales of the Firm during the 12-month period preceding the most recent...-month versus twenty-four month decline. Based upon a comparison of the most recent 12-month period for...

13 CFR 315.7 - Certification requirements.

Code of Federal Regulations, 2010 CFR

2010-01-01

...) Minimum certification thresholds. (1) Twelve-month decline. Based upon a comparison of the most recent 12... percent of the total production or sales of the Firm during the 12-month period preceding the most recent...-month versus twenty-four month decline. Based upon a comparison of the most recent 12-month period for...

Numerical and analytical bounds on threshold error rates for hypergraph-product codes

NASA Astrophysics Data System (ADS)

Kovalev, Alexey A.; Prabhakar, Sanjay; Dumer, Ilya; Pryadko, Leonid P.

2018-06-01

We study analytically and numerically decoding properties of finite-rate hypergraph-product quantum low density parity-check codes obtained from random (3,4)-regular Gallager codes, with a simple model of independent X and Z errors. Several nontrivial lower and upper bounds for the decodable region are constructed analytically by analyzing the properties of the homological difference, equal minus the logarithm of the maximum-likelihood decoding probability for a given syndrome. Numerical results include an upper bound for the decodable region from specific heat calculations in associated Ising models and a minimum-weight decoding threshold of approximately 7 % .

On-Orbit Reconfigurable Solar Array

NASA Technical Reports Server (NTRS)

Levy, Robert K. (Inventor)

2017-01-01

In one or more embodiments, the present disclosure teaches a method for reconfiguring a solar array. The method involves providing, for the solar array, at least one string of solar cells. The method further involves deactivating at least a portion of at least one of the strings of solar cells of the solar array when power produced by the solar array reaches a maximum power allowance threshold. In addition, the method involves activating at least a portion of at least one of the strings of the solar cells in the solar array when the power produced by the solar array reaches a minimum power allowance threshold.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zubov, F. I.; Kryzhanovskaya, N. V.; Moiseev, E. I.

The spectral, threshold, and power characteristics of a microdisk laser 31 μm in diameter with an active region based on InAs/InGaAs quantum dots, operating in the continuous-wave (cw) mode at room temperature are studied. The minimum threshold current density is 0.58 kA/cm{sup 2}, the subthreshold linewidth of the whispering-gallery mode is 50 pm at a wavelength lying in the range of 1.26–1.27 μm. The total power emitted into free space reaches ~0.1 mW in the cw mode, whereas the radiation power of the whispering-gallery modes is ~2.8%.

Monitoring the compliance of the academic enterprise with the Fair Labor Standards Act

PubMed Central

Bankston, Adriana; McDowell, Gary S.

2017-01-01

Background: On December 1, 2016, the Fair Labor Standards Act (FLSA) was due to be updated by the U.S. Department of Labor. Key changes included an increase in the salary threshold for exemption from overtime for working more than 40 hours per week, and indexing the salary level so that it is updated automatically every 3 years. This was predicted to have a profound effect on academe as postdoctoral researchers were mostly paid at a salary below the new threshold. On November 22, 2016, an injunction was granted nationwide, delaying implementation of the updates, which were finally struck down entirely on August 31, 2017. Here we review the key changes to the FLSA, how they came about, and how the postdoctoral population was affected. Methods: We describe recent data collection efforts to uncover what institutions with postdocs were doing to comply with the FLSA. Results: Our data showed that 57% of institutions checked (containing 41% of the estimated postdoctoral workforce in science, engineering and health) had not decided or had no public decision available one month prior to implementation, and only 35.5% of institutions were planning to raise salaries to the new minimum. After the injunction, a number of institutions and the NIH continued with their plans to raise salaries. Overall, despite the removal of a federal mandate, approximately 60% of postdocs are at institutions whose policy is to raise salaries. Conclusions: Our data show uncertainty in postdoctoral salaries in the U.S. prior to implementation of the FLSA ruling. In addition, while some institutions did suspend plans to raise postdoctoral salaries after the injunction, many continued with the raise. The implementation of postdoctoral salary raises may be inconsistent, however, as the legal minimum is still $23,660. PMID:27990268

Are Alcohol Taxation and Pricing Policies Regressive? Product-Level Effects of a Specific Tax and a Minimum Unit Price for Alcohol.

PubMed

Vandenberg, Brian; Sharma, Anurag

2016-07-01

To compare estimated effects of two policy alternatives, (i) a minimum unit price (MUP) for alcohol and (ii) specific (per-unit) taxation, upon current product prices, per capita spending (A$), and per capita consumption by income quintile, consumption quintile and product type. Estimation of baseline spending and consumption, and modelling policy-to-price and price-to-consumption effects of policy changes using scanner data from a panel of demographically representative Australian households that includes product-level details of their off-trade alcohol spending (n = 885; total observations = 12,505). Robustness checks include alternative price elasticities, tax rates, minimum price thresholds and tax pass-through rates. Current alcohol taxes and alternative taxation and pricing policies are not highly regressive. Any regressive effects are small and concentrated among heavy consumers. The lowest-income consumers currently spend a larger proportion of income (2.3%) on alcohol taxes than the highest-income consumers (0.3%), but the mean amount is small in magnitude [A$5.50 per week (95%CI: 5.18-5.88)]. Both a MUP and specific taxation will have some regressive effects, but the effects are limited, as they are greatest for the heaviest consumers, irrespective of income. Among the policy alternatives, a MUP is more effective in reducing consumption than specific taxation, especially for consumers in the lowest-income quintile: an estimated mean per capita reduction of 11.9 standard drinks per week (95%CI: 11.3-12.6). Policies that increase the cost of the cheapest alcohol can be effective in reducing alcohol consumption, without having highly regressive effects. © The Author 2015. Medical Council on Alcohol and Oxford University Press. All rights reserved.

Seawater and shellfish (Geukensia demissa) quality along the Western Coast of Assateague Island National Seashore, Maryland: an area impacted by feral horses and agricultural runoff.

PubMed

Lambert, Mary S; Ozbay, Gulnihal; Richards, Gary P

2009-08-01

We evaluated the quality of seawater and ribbed mussels (Gukensia demissa) at six sites along the West Coast of Assateague Island National Seashore (ASIS), a barrier island popular with tourists and fishermen. Parameters evaluated were summertime temperature, pH, salinity, dissolved oxygen, total phosphorus, total ammonia nitrogen, and nitrite levels for seawater and total heterotrophic plate counts and total Vibrionaceae levels for the ribbed mussels. Approximately 150 feral horses (Equus caballus) are located on ASIS and, combined with agricultural runoff from animals and croplands, local wildlife, and anthropogenic inputs, contribute to nutrient loads affecting water and shellfish quality. The average monthly dissolved oxygen for June was 2.65 mg L(-1), below the minimum acceptable threshold of 3.0 mg L(-1). Along Chincoteague Bay, total phosphorus generally exceeded the maximum level of 0.037 mg L(-1), as set by the Maryland Coastal Bays Program management objective for seagrasses, with a high of 1.92 mg L(-1) in June, some 50-fold higher than the recommended threshold. Total ammonia nitrogen approached levels harmful to fish, with a maximum recorded value of 0.093 mg L(-1). Levels of total heterotrophic bacteria spiked to 9.5 x 10(6) cells g(-1) of mussel tissue in August in Sinepuxent Bay, leading to mussels which exceeded acceptable standards for edible bivalves by 19-fold. An average of 76% of the bacterial isolates were in the Vibrionaceae family. Together, these data suggest poor stewardship of our coastal environment and the need for new intervention strategies to reduce chemical and biological contamination of our marine resources.

Age structure and mortality of walleyes in Kansas reservoirs: Use of mortality caps to establish realistic management objectives

USGS Publications Warehouse

Quist, M.C.; Stephen, J.L.; Guy, C.S.; Schultz, R.D.

2004-01-01

Age structure, total annual mortality, and mortality caps (maximum mortality thresholds established by managers) were investigated for walleye Sander vitreus (formerly Stizostedion vitreum) populations sampled from eight Kansas reservoirs during 1991-1999. We assessed age structure by examining the relative frequency of different ages in the population; total annual mortality of age-2 and older walleyes was estimated by use of a weighted catch curve. To evaluate the utility of mortality caps, we modeled threshold values of mortality by varying growth rates and management objectives. Estimated mortality thresholds were then compared with observed growth and mortality rates. The maximum age of walleyes varied from 5 to 11 years across reservoirs. Age structure was dominated (???72%) by walleyes age 3 and younger in all reservoirs, corresponding to ages that were not yet vulnerable to harvest. Total annual mortality rates varied from 40.7% to 59.5% across reservoirs and averaged 51.1% overall (SE = 2.3). Analysis of mortality caps indicated that a management objective of 500 mm for the mean length of walleyes harvested by anglers was realistic for all reservoirs with a 457-mm minimum length limit but not for those with a 381-mm minimum length limit. For a 500-mm mean length objective to be realized for reservoirs with a 381-mm length limit, managers must either reduce mortality rates (e.g., through restrictive harvest regulations) or increase growth of walleyes. When the assumed objective was to maintain the mean length of harvested walleyes at current levels, the observed annual mortality rates were below the mortality cap for all reservoirs except one. Mortality caps also provided insight on management objectives expressed in terms of proportional stock density (PSD). Results indicated that a PSD objective of 20-40 was realistic for most reservoirs. This study provides important walleye mortality information that can be used for monitoring or for inclusion into population models; these results can also be combined with those of other studies to investigate large-scale differences in walleye mortality. Our analysis illustrates the utility of mortality caps for monitoring walleye populations and for establishing realistic management goals.

Laser-induced retinal damage thresholds for annular retinal beam profiles

NASA Astrophysics Data System (ADS)

Kennedy, Paul K.; Zuclich, Joseph A.; Lund, David J.; Edsall, Peter R.; Till, Stephen; Stuck, Bruce E.; Hollins, Richard C.

2004-07-01

The dependence of retinal damage thresholds on laser spot size, for annular retinal beam profiles, was measured in vivo for 3 μs, 590 nm pulses from a flashlamp-pumped dye laser. Minimum Visible Lesion (MVL)ED50 thresholds in rhesus were measured for annular retinal beam profiles covering 5, 10, and 20 mrad of visual field; which correspond to outer beam diameters of roughly 70, 160, and 300 μm, respectively, on the primate retina. Annular beam profiles at the retinal plane were achieved using a telescopic imaging system, with the focal properties of the eye represented as an equivalent thin lens, and all annular beam profiles had a 37% central obscuration. As a check on experimental data, theoretical MVL-ED50 thresholds for annular beam exposures were calculated using the Thompson-Gerstman granular model of laser-induced thermal damage to the retina. Threshold calculations were performed for the three experimental beam diameters and for an intermediate case with an outer beam diameter of 230 μm. Results indicate that the threshold vs. spot size trends, for annular beams, are similar to the trends for top hat beams determined in a previous study; i.e., the threshold dose varies with the retinal image area for larger image sizes. The model correctly predicts the threshold vs. spot size trends seen in the biological data, for both annular and top hat retinal beam profiles.

Optimized breast MRI functional tumor volume as a biomarker of recurrence-free survival following neoadjuvant chemotherapy.

PubMed

Jafri, Nazia F; Newitt, David C; Kornak, John; Esserman, Laura J; Joe, Bonnie N; Hylton, Nola M

2014-08-01

To evaluate optimal contrast kinetics thresholds for measuring functional tumor volume (FTV) by breast magnetic resonance imaging (MRI) for assessment of recurrence-free survival (RFS). In this Institutional Review Board (IRB)-approved retrospective study of 64 patients (ages 29-72, median age of 48.6) undergoing neoadjuvant chemotherapy (NACT) for breast cancer, all patients underwent pre-MRI1 and postchemotherapy MRI4 of the breast. Tumor was defined as voxels meeting thresholds for early percent enhancement (PEthresh) and early-to-late signal enhancement ratio (SERthresh); and FTV (PEthresh, SERthresh) by summing all voxels meeting threshold criteria and minimum connectivity requirements. Ranges of PEthresh from 50% to 220% and SERthresh from 0.0 to 2.0 were evaluated. A Cox proportional hazard model determined associations between change in FTV over treatment and RFS at different PE and SER thresholds. The plot of hazard ratios for change in FTV from MRI1 to MRI4 showed a broad peak with the maximum hazard ratio and highest significance occurring at PE threshold of 70% and SER threshold of 1.0 (hazard ratio = 8.71, 95% confidence interval 2.86-25.5, P < 0.00015), indicating optimal model fit. Enhancement thresholds affect the ability of MRI tumor volume to predict RFS. The value is robust over a wide range of thresholds, supporting the use of FTV as a biomarker. © 2013 Wiley Periodicals, Inc.

Gradient-driven flux-tube simulations of ion temperature gradient turbulence close to the non-linear threshold

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peeters, A. G.; Rath, F.; Buchholz, R.

2016-08-15

It is shown that Ion Temperature Gradient turbulence close to the threshold exhibits a long time behaviour, with smaller heat fluxes at later times. This reduction is connected with the slow growth of long wave length zonal flows, and consequently, the numerical dissipation on these flows must be sufficiently small. Close to the nonlinear threshold for turbulence generation, a relatively small dissipation can maintain a turbulent state with a sizeable heat flux, through the damping of the zonal flow. Lowering the dissipation causes the turbulence, for temperature gradients close to the threshold, to be subdued. The heat flux then doesmore » not go smoothly to zero when the threshold is approached from above. Rather, a finite minimum heat flux is obtained below which no fully developed turbulent state exists. The threshold value of the temperature gradient length at which this finite heat flux is obtained is up to 30% larger compared with the threshold value obtained by extrapolating the heat flux to zero, and the cyclone base case is found to be nonlinearly stable. Transport is subdued when a fully developed staircase structure in the E × B shearing rate forms. Just above the threshold, an incomplete staircase develops, and transport is mediated by avalanche structures which propagate through the marginally stable regions.« less

Confronting Regulatory Cost and Quality Expectations. An Exploration of Technical Change in Minimum Efficiency Performance Standards

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, Margaret; Spurlock, C. Anna; Yang, Hung-Chia

The dual purpose of this project was to contribute to basic knowledge about the interaction between regulation and innovation and to inform the cost and benefit expectations related to technical change which are embedded in the rulemaking process of an important area of national regulation. The area of regulation focused on here is minimum efficiency performance standards (MEPS) for appliances and other energy-using products. Relevant both to U.S. climate policy and energy policy for buildings, MEPS remove certain product models from the market that do not meet specified efficiency thresholds.

Acid rain research program. Annual progress report, September 1975--June 1976

DOE Office of Scientific and Technical Information (OSTI.GOV)

Evans, L.S.; Raynor, G.S.

1976-09-01

The aims of the research program are: (a) to observe the minimum threshold dose of simulated acid rain to produce visual and histological effects on plant foliage, (b) approach threshold limits of simulated sulfate acid rain that affect plant growth and reproduction, and (c) to measure chemical and meteorological parameters of incident rain. Acute leaf injury to several plant species resulted from exposure of foliage to simulated sulfate acid rain of pH level 2.3 to 2.9. Only slight injury occurred at 3.1. Scanning electron micrographs showed that injury to upper leaf surfaces occurred mostly at the base of trichomes (leafmore » hairs) and near stomata. An association of lesion development near vascular tissue was also noted. Histologically, lesions are characterized by an initial collapse of the epidermis with eventual lysis and collapse of more internal leaf tissues on the upper leaf surface of pinto beans which complemented detailed descriptions of visual lesion development after daily exposures to simulated rain. Initial experiments with gametophytes of Pteridium aquilinum show that reproduction of this fern species is very sensitive to solutions of pH 5.2 while vegetative development is not affected at pH levels of 2.2. Initial rain samples from the sequential sampler have been obtained. Initial portions of rain events exhibit a pH near 3.0 in some cases. More complete chemical analyses are anticipated.« less

Variability in daily pH scales with coral reef accretion and community structure

NASA Astrophysics Data System (ADS)

Price, N.; Martz, T.; Brainard, R. E.; Smith, J.

2011-12-01

Little is known about natural variability in pH in coastal waters and how resident organisms respond to current nearshore seawater conditions. We used autonomous sensors (SeaFETs) to record temperature and, for the first time, pH with high temporal (hourly observations; 7 months of sampling) resolution on the reef benthos (5-10m depth) at several islands (Kingman, Palmyra and Jarvis) within the newly designated Pacific Remote Island Areas Marine National Monument (PRIMNM) in the northern Line Islands; these islands are uninhabited and lack potentially confounding local impacts (e.g. pollution and overfishing). Recorded benthic pH values were compared with regional means and minimum thresholds based on seasonal amplitude estimated from surrounding open-ocean climatological data, which represent seawater chemistry values in the absence of feedback from the reef. Each SeaFET sensor was co-located with replicate Calcification/Acidification Units (CAUs) designed to quantify species abundances and net community calcification rates so we could determine which, if any, metrics of natural variability in benthic pH and temperature were related to community development and reef accretion rates. The observed range in daily pH encompassed maximums reported from the last century (8.104 in the early evening) to minimums approaching projected levels within the next 100 yrs (7.824 at dawn) for pelagic waters. Net reef calcification rates, measured as calcium carbonate accretion on CAUs, varied within and among islands and were comparable with rates measured from the Pacific and Caribbean using chemistry-based approaches. Benthic species assemblages on the CAUs were differentiated by the presence of calcifying and fleshy taxa (CAP analysis, mean allocation success 80%, δ2 = 0.886, P = <0.001). In general, accretion rates were higher at sites that had a greater number of hours at high pH values each day. Where daily pH failed to exceed climatological seasonal minimum thresholds, net accretion was slower and fleshy, non-calcifying benthic organisms dominated. Natural variation in benthic pH offers a unique opportunity to study ecological consequences of likely future ocean chemistry.

Electrophysiological performance of a bipolar membrane-coated titanium nitride electrode: a randomized comparison of steroid and nonsteroid lead designs.

PubMed

Wiegand, U K; Zhdanov, A; Stammwitz, E; Crozier, I; Claessens, R J; Meier, J; Bos, R J; Bode, F; Potratz, J

1999-06-01

The aim of this multicenter study was to investigate the performance of a new cardiac pacemaker lead with a titanium nitride cathode coated with a copolymer membrane. In particular, the electrophysiological effect of steroid dissolved in this ion-exchange membrane was evaluated by randomized comparison. Ninety-five patients were randomized either to the 1450 T (n = 51) or the 1451 T ventricular lead (n = 45) and received telemeteral VVI(R) pacemakers with identical diagnostic features. Both leads were bipolar, were passively affixed, and had a porous titanium nitride tip with a surface area of 3.5 mm2. The only difference between the two electrodes was 13 micrograms of dexamethasone added to the 1450 Ts membrane coating. Voltage thresholds (VTH) at pulse durations of 0.25, 0.37, and 0.5 ms, lead impedance, and sensing thresholds were measured at discharge, 2 weeks, 1 month, 3 months, and 6 months after implantation. Mean amplitude and the slew rate from three telemetered intracardiac electrograms, chronaxie-rheobase product, and minimum energy consumption were calculated. After a 6-month follow-up, mean voltage thresholds of 0.65 +/- 0.20 V and 0.63 +/- 0.34 were achieved for the 1450 T lead and 1451 T lead, respectively. As a result, a VTH < 1.0 V was obtained in all patients with 1450 T electrodes and in 97.7% of patients with 1451 T leads after 6 months follow-up. In both electrodes, stable VTH was reached 2 weeks after implantation, and no transient rise in threshold was observed. No differences were observed between the steroid and the nonsteroid group in respect to VTH, chronaxie-rheobase product, minimum energy consumption, and potential amplitude and slew rate. In conclusion, safe and efficient pacing at low pulse amplitudes were achieved with both leads. The tip design, independently of the steroid additive, prevented any energy-consuming increases in the voltage threshold.

Age-related changes in perception of movement in driving scenes.

PubMed

Lacherez, Philippe; Turner, Laura; Lester, Robert; Burns, Zoe; Wood, Joanne M

2014-07-01

Age-related changes in motion sensitivity have been found to relate to reductions in various indices of driving performance and safety. The aim of this study was to investigate the basis of this relationship in terms of determining which aspects of motion perception are most relevant to driving. Participants included 61 regular drivers (age range 22-87 years). Visual performance was measured binocularly. Measures included visual acuity, contrast sensitivity and motion sensitivity assessed using four different approaches: (1) threshold minimum drift rate for a drifting Gabor patch, (2) Dmin from a random dot display, (3) threshold coherence from a random dot display, and (4) threshold drift rate for a second-order (contrast modulated) sinusoidal grating. Participants then completed the Hazard Perception Test (HPT) in which they were required to identify moving hazards in videos of real driving scenes, and also a Direction of Heading task (DOH) in which they identified deviations from normal lane keeping in brief videos of driving filmed from the interior of a vehicle. In bivariate correlation analyses, all motion sensitivity measures significantly declined with age. Motion coherence thresholds, and minimum drift rate threshold for the first-order stimulus (Gabor patch) both significantly predicted HPT performance even after controlling for age, visual acuity and contrast sensitivity. Bootstrap mediation analysis showed that individual differences in DOH accuracy partly explained these relationships, where those individuals with poorer motion sensitivity on the coherence and Gabor tests showed decreased ability to perceive deviations in motion in the driving videos, which related in turn to their ability to detect the moving hazards. The ability to detect subtle movements in the driving environment (as determined by the DOH task) may be an important contributor to effective hazard perception, and is associated with age, and an individuals' performance on tests of motion sensitivity. The locus of the processing deficits appears to lie in first-order, rather than second-order motion pathways. © 2014 The Authors Ophthalmic & Physiological Optics © 2014 The College of Optometrists.

Predictive minimum description length principle approach to inferring gene regulatory networks.

PubMed

Chaitankar, Vijender; Zhang, Chaoyang; Ghosh, Preetam; Gong, Ping; Perkins, Edward J; Deng, Youping

2011-01-01

Reverse engineering of gene regulatory networks using information theory models has received much attention due to its simplicity, low computational cost, and capability of inferring large networks. One of the major problems with information theory models is to determine the threshold that defines the regulatory relationships between genes. The minimum description length (MDL) principle has been implemented to overcome this problem. The description length of the MDL principle is the sum of model length and data encoding length. A user-specified fine tuning parameter is used as control mechanism between model and data encoding, but it is difficult to find the optimal parameter. In this work, we propose a new inference algorithm that incorporates mutual information (MI), conditional mutual information (CMI), and predictive minimum description length (PMDL) principle to infer gene regulatory networks from DNA microarray data. In this algorithm, the information theoretic quantities MI and CMI determine the regulatory relationships between genes and the PMDL principle method attempts to determine the best MI threshold without the need of a user-specified fine tuning parameter. The performance of the proposed algorithm is evaluated using both synthetic time series data sets and a biological time series data set (Saccharomyces cerevisiae). The results show that the proposed algorithm produced fewer false edges and significantly improved the precision when compared to existing MDL algorithm.

Extrinsic regime shifts drive abrupt changes in regeneration dynamics at upper treeline in the Rocky Mountains, U.S.A.

PubMed

Elliott, Grant P

2012-07-01

Given the widespread and often dramatic influence of climate change on terrestrial ecosystems, it is increasingly common for abrupt threshold changes to occur, yet explicitly testing for climate and ecological regime shifts is lacking in climatically sensitive upper treeline ecotones. In this study, quantitative evidence based on empirical data is provided to support the key role of extrinsic, climate-induced thresholds in governing the spatial and temporal patterns of tree establishment in these high-elevation environments. Dendroecological techniques were used to reconstruct a 420-year history of regeneration dynamics within upper treeline ecotones along a latitudinal gradient (approximately 44-35 degrees N) in the Rocky Mountains. Correlation analysis was used to assess the possible influence of minimum and maximum temperature indices and cool-season (November-April) precipitation on regional age-structure data. Regime-shift analysis was used to detect thresholds in tree establishment during the entire period of record (1580-2000), temperature variables significantly Correlated with establishment during the 20th century, and cool-season precipitation. Tree establishment was significantly correlated with minimum temperature during the spring (March-May) and cool season. Regime-shift analysis identified an abrupt increase in regional tree establishment in 1950 (1950-1954 age class). Coincident with this period was a shift toward reduced cool-season precipitation. The alignment of these climate conditions apparently triggered an abrupt increase in establishment that was unprecedented during the period of record. Two main findings emerge from this research that underscore the critical role of climate in governing regeneration dynamics within upper treeline ecotones. (1) Regional climate variability is capable of exceeding bioclimatic thresholds, thereby initiating synchronous and abrupt changes in the spatial and temporal patterns of tree establishment at broad regional scales. (2) The importance of climate parameters exceeding critical threshold values and triggering a regime shift in tree establishment appears to be contingent on the alignment of favorable temperature and moisture regimes. This research suggests that threshold changes in the climate system can fundamentally alter regeneration dynamics within upper treeline ecotones and, through the use of regime-shift analysis, reveals important climate-vegetation linkages.

Atmospheric CO2 at Waliguan station in China: Transport climatology, temporal patterns and source-sink region representativeness

NASA Astrophysics Data System (ADS)

Cheng, Siyang; An, Xingqin; Zhou, Lingxi; Tans, Pieter P.; Jacobson, Andy

2017-06-01

In order to explore where the source and sink have the greatest impact on CO2 background concentration at Waliguan (WLG) station, a statistical method is here proposed to calculate the representative source-sink region. The key to this method is to find the best footprint threshold, and the study is carried out in four parts. Firstly, transport climatology, expressed by total monthly footprint, was simulated by FLEXPART on a 7-day time scale. Surface CO2 emissions in Eurasia frequently transported to WLG station. WLG station was mainly influenced by the westerlies in winter and partly controlled by the Southeast Asian monsoon in summer. Secondly, CO2 concentrations, simulated by CT2015, were processed and analyzed through data quality control, screening, fitting and comparing. CO2 concentrations displayed obvious seasonal variation, with the maximum and minimum concentration appearing in April and August, respectively. The correlation of CO2 fitting background concentrations was R2 = 0.91 between simulation and observation. The temporal patterns were mainly correlated with CO2 exchange of biosphere-atmosphere, human activities and air transport. Thirdly, for the monthly CO2 fitting background concentrations from CT2015, a best footprint threshold was found based on correlation analysis and numerical iteration using the data of footprints and emissions. The grid cells where monthly footprints were greater than the best footprint threshold were the best threshold area corresponding to representative source-sink region. The representative source-sink region of maximum CO2 concentration in April was primarily located in Qinghai province, but the minimum CO2 concentration in August was mainly influenced by emissions in a wider region. Finally, we briefly presented the CO2 source-sink characteristics in the best threshold area. Generally, the best threshold area was a carbon sink. The major source and sink were relatively weak owing to less human activities and vegetation types in this high altitude area. CO2 concentrations were more influenced by human activities when air mass passed through many urban areas in summer. Therefore, the combination of footprints and emissions is an effective approach for assessing the source-sink region representativeness of CO2 background concentration.

Poole Frenkel current and Schottky emission in SiN gate dielectric in AlGaN/GaN metal insulator semiconductor heterostructure field effect transistors

NASA Astrophysics Data System (ADS)

Hanna, Mina J.; Zhao, Han; Lee, Jack C.

2012-10-01

We analyze the anomalous I-V behavior in SiN prepared by plasma enhanced chemical vapor deposition for use as a gate insulator in AlGaN/GaN metal insulator semiconductor heterostructure filed effect transistors (HFETs). We observe leakage current across the dielectric with opposite polarity with respect to the applied electric field once the voltage sweep reaches a level below a determined threshold. This is observed as the absolute minimum of the leakage current does not occur at minimum voltage level (0 V) but occurs earlier in the sweep interval. Curve-fitting analysis suggests that the charge-transport mechanism in this region is Poole-Frenkel current, followed by Schottky emission due to band bending. Despite the current anomaly, the sample devices have shown a notable reduction of leakage current of over 2 to 6 order of magnitudes compared to the standard Schottky HFET. We show that higher pressures and higher silane concentrations produce better films manifesting less trapping. This conforms to our results that we reported in earlier publications. We found that higher chamber pressure achieves higher sheet carrier concentration that was found to be strongly dependent on the trapped space charge at the SiN/GaN interface. This would suggest that a lower chamber pressure induces more trap states into the SiN/GaN interface.

Resource-aware system architecture model for implementation of quantum aided Byzantine agreement on quantum repeater networks

NASA Astrophysics Data System (ADS)

Taherkhani, Mohammand Amin; Navi, Keivan; Van Meter, Rodney

2018-01-01

Quantum aided Byzantine agreement is an important distributed quantum algorithm with unique features in comparison to classical deterministic and randomized algorithms, requiring only a constant expected number of rounds in addition to giving a higher level of security. In this paper, we analyze details of the high level multi-party algorithm, and propose elements of the design for the quantum architecture and circuits required at each node to run the algorithm on a quantum repeater network (QRN). Our optimization techniques have reduced the quantum circuit depth by 44% and the number of qubits in each node by 20% for a minimum five-node setup compared to the design based on the standard arithmetic circuits. These improvements lead to a quantum system architecture with 160 qubits per node, space-time product (an estimate of the required fidelity) {KQ}≈ 1.3× {10}5 per node and error threshold 1.1× {10}-6 for the total nodes in the network. The evaluation of the designed architecture shows that to execute the algorithm once on the minimum setup, we need to successfully distribute a total of 648 Bell pairs across the network, spread evenly between all pairs of nodes. This framework can be considered a starting point for establishing a road-map for light-weight demonstration of a distributed quantum application on QRNs.

Near-threshold fatigue crack behaviour in EUROFER 97 at different temperatures

NASA Astrophysics Data System (ADS)

Aktaa, J.; Lerch, M.

2006-07-01

The fatigue crack behaviour in EUROFER 97 was investigated at room temperature (RT), 300, 500 and 550 °C for the assessment of cracks in first wall structures built from EUROFER 97 of future fusion reactors. For this purpose, fatigue crack growth tests were performed using CT specimens with two R-ratios, R = 0.1 and R = 0.5 ( R is the load ratio with R = Fmin/ Fmax where Fmin and Fmax are the minimum and maximum applied loads within a cycle, respectively). Hence, fatigue crack threshold, fatigue crack growth behaviour in the near-threshold range and their dependences on temperature and R-ratio were determined and described using an analytical formula. The fatigue crack threshold showed a monotonous dependence on temperature which is for R = 0.5 insignificantly small. The fatigue crack growth behaviour exhibited for R = 0.1 a non-monotonous dependence on temperature which is explained by the decrease of yield stress and the increase of creep damage with increasing temperature.

Multi-thresholds for fault isolation in the presence of uncertainties.

PubMed

Touati, Youcef; Mellal, Mohamed Arezki; Benazzouz, Djamel

2016-05-01

Monitoring of the faults is an important task in mechatronics. It involves the detection and isolation of faults which are performed by using the residuals. These residuals represent numerical values that define certain intervals called thresholds. In fact, the fault is detected if the residuals exceed the thresholds. In addition, each considered fault must activate a unique set of residuals to be isolated. However, in the presence of uncertainties, false decisions can occur due to the low sensitivity of certain residuals towards faults. In this paper, an efficient approach to make decision on fault isolation in the presence of uncertainties is proposed. Based on the bond graph tool, the approach is developed in order to generate systematically the relations between residuals and faults. The generated relations allow the estimation of the minimum detectable and isolable fault values. The latter is used to calculate the thresholds of isolation for each residual. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

An Auditory-Masking-Threshold-Based Noise Suppression Algorithm GMMSE-AMT[ERB] for Listeners with Sensorineural Hearing Loss

NASA Astrophysics Data System (ADS)

Natarajan, Ajay; Hansen, John H. L.; Arehart, Kathryn Hoberg; Rossi-Katz, Jessica

2005-12-01

This study describes a new noise suppression scheme for hearing aid applications based on the auditory masking threshold (AMT) in conjunction with a modified generalized minimum mean square error estimator (GMMSE) for individual subjects with hearing loss. The representation of cochlear frequency resolution is achieved in terms of auditory filter equivalent rectangular bandwidths (ERBs). Estimation of AMT and spreading functions for masking are implemented in two ways: with normal auditory thresholds and normal auditory filter bandwidths (GMMSE-AMT[ERB]-NH) and with elevated thresholds and broader auditory filters characteristic of cochlear hearing loss (GMMSE-AMT[ERB]-HI). Evaluation is performed using speech corpora with objective quality measures (segmental SNR, Itakura-Saito), along with formal listener evaluations of speech quality rating and intelligibility. While no measurable changes in intelligibility occurred, evaluations showed quality improvement with both algorithm implementations. However, the customized formulation based on individual hearing losses was similar in performance to the formulation based on the normal auditory system.

Do Atmospheric Rivers explain the extreme precipitation events over East Asia?

NASA Astrophysics Data System (ADS)

Dairaku, K.; Nayak, S.

2017-12-01

Extreme precipitation events are now of serious concern due to their damaging societal impacts over last few decades. Thus, climate indices are widely used to identify and quantify variability and changes in particular aspects of the climate system, especially when considering extremes. In our study, we focus on few climate indices of annual precipitation extremes for the period 1979-2013 over East Asia to discuss some straightforward information and interpretation of certain aspects of extreme precipitation events that occur over the region. To do so, we first discuss different percentiles of precipitation and maximum length of wet spell with different thresholds from a regional climate model (NRAMS) simulation at 20km. Results indicate that the 99 percentile of precipitation events correspond to about 80mm/d over few regions of East Asia during 1979-2013 and maximum length of wet spell with minimum 20mm precipitation corresponds to about 10days (Figure 1). We then linked the extreme precipitation events with the intense moisture transport events associated with atmospheric rivers (ARs). The ARs are identified by computing the vertically integrated horizontal water vapor transport (IVT) between 1000hpa and 300hpa with IVT ≥ 250 kg/m/s and 2000 km minimum long. With this threshold and condition (set by previous research), our results indicate that some extreme propitiation events are associated with some ARs over East Asia, while some events are not associated with any ARs. Similarly, some ARs are associated with some extreme precipitation events, while some ARs are not associated with any events. Since the ARs are sensitive to the threshold and condition depending on region, so we will analyze the characteristics of ARs (frequency, duration, and annual variability) with different thresholds and discuss their relationship with extreme precipitation events over East Asia.

Consortia Formation and Characteristics under the "Carl D. Perkins Career and Technical Education Act of 2006"

ERIC Educational Resources Information Center

Staklis, Sandra; Klein, Steve

2014-01-01

The "Carl D. Perkins Career and Technical Education Act of 2006" ("Perkins IV") sets a minimum allocation requirement that secondary and postsecondary career and technical education (CTE) subgrantees must achieve to receive federal financing. An eligible recipient with an allocation below the funding threshold may obtain a…

Reduced Sensitivity to Minimum-Jerk Biological Motion in Autism Spectrum Conditions

ERIC Educational Resources Information Center

Cook, Jennifer; Saygin, Ayse Pinar; Swain, Rachel; Blakemore, Sarah-Jayne

2009-01-01

We compared psychophysical thresholds for biological and non-biological motion detection in adults with autism spectrum conditions (ASCs) and controls. Participants watched animations of a biological stimulus (a moving hand) or a non-biological stimulus (a falling tennis ball). The velocity profile of the movement was varied between 100% natural…

Social Mobility and Reproduction for Whom? College Readiness and First-Year Retention

ERIC Educational Resources Information Center

DeAngelo, Linda; Franke, Ray

2016-01-01

Completing college is now the minimum threshold for entry into the middle class. This has pushed college readiness issues to the forefront in efforts to increase educational attainment. Little is known about how college readiness improves outcomes for students traditionally marginalized in educational settings or if social background factors…

The Role of the Geographic Combatant Commander in Counterproliferation of Nuclear Weapons

DTIC Science & Technology

2007-04-05

nuclear yield is beyond the scope of this paper; however, this value is above the 20% threshold of HEU meaning that at a minimum HEU is required for... introversion has created an environment where communication and cooperation is almost impossible. This inability to cooperate goes beyond relations between

Minimum threshold for establishment and dispersal of Lilioceris cheni (Coleoptera: Chrysomelide): a biological control agent of Dioscorea bulbifera

USDA-ARS?s Scientific Manuscript database

The successful establishment or failure of a new population is often attributed to propagule pressure, the combination of the number of independent introduction events, and the number of individuals released at each event. Design of optimal release strategies for biological control agents benefits f...

Automated storm water sampling on small watersheds

USGS Publications Warehouse

Harmel, R.D.; King, K.W.; Slade, R.M.

2003-01-01

Few guidelines are currently available to assist in designing appropriate automated storm water sampling strategies for small watersheds. Therefore, guidance is needed to develop strategies that achieve an appropriate balance between accurate characterization of storm water quality and loads and limitations of budget, equipment, and personnel. In this article, we explore the important sampling strategy components (minimum flow threshold, sampling interval, and discrete versus composite sampling) and project-specific considerations (sampling goal, sampling and analysis resources, and watershed characteristics) based on personal experiences and pertinent field and analytical studies. These components and considerations are important in achieving the balance between sampling goals and limitations because they determine how and when samples are taken and the potential sampling error. Several general recommendations are made, including: setting low minimum flow thresholds, using flow-interval or variable time-interval sampling, and using composite sampling to limit the number of samples collected. Guidelines are presented to aid in selection of an appropriate sampling strategy based on user's project-specific considerations. Our experiences suggest these recommendations should allow implementation of a successful sampling strategy for most small watershed sampling projects with common sampling goals.

Minimum velocity necessary for nonconventional projectiles to penetrate the eye: an experimental study using pig eyes.

PubMed

Marshall, John W; Dahlstrom, Dean B; Powley, Kramer D

2011-06-01

To satisfy the Criminal Code of Canada's definition of a firearm, a barreled weapon must be capable of causing serious bodily injury or death to a person. Canadian courts have accepted the forensically established criteria of "penetration or rupture of an eye" as serious bodily injury. The minimal velocity of nonconventional ammunition required to penetrate the eye including airsoft projectiles has yet to be established. To establish minimal threshold requirements for eye penetration, empirical tests were conducted using a variety of airsoft projectiles. Using the data obtained from these tests, and previous research using "air gun" projectiles, an "energy density" parameter was calculated for the minimum penetration threshold of an eye. Airsoft guns capable of achieving velocities in excess of 99 m/s (325 ft/s) using conventional 6-mm airsoft ammunition will satisfy the forensically established criteria of "serious bodily injury." The energy density parameter for typical 6-mm plastic airsoft projectiles is 4.3 to 4.8 J/cm². This calculation also encompasses 4.5-mm steel BBs.

Factors associated with the seasonality of blood lead levels among preschool Wisconsin children.

PubMed

Havlena, Jeff; Kanarek, Marty S; Coons, Margie

2009-05-01

Aggregate blood lead testing data for Wisconsin children younger than age 6 exhibit seasonal trends in both average blood lead levels and in the percent of those tested and found to have blood lead levels in excess of the 10 mcg/dL threshold for poisoning. Blood lead levels and poisoning rates typically peak during the late summer and early fall months, and are at their minimum during the late winter. Blood test data was analyzed to determine variations by month and age. Seasonal variations are evident even among the very young: infants younger than 10 months who likely have limited opportunity to encounter lead hazards within their home or in the outdoor soil. Seasonal periodicity is most evident among infants who reside in very urban and very rural communities. The observed seasonal periodicity might be associated with the seasonal availability of lead within the children's environment. Particulate matter data measured at several ambient air quality monitoring stations exhibit a similar periodic seasonality, suggesting a possible relationship between blood lead levels and the availability of dust and airborne particulates during the summer months. Clinicians should consider the seasonality of blood lead levels when scheduling tests and interpreting test results.

Non-linear effects of mean temperature and relative humidity on dengue incidence in Guangzhou, China.

PubMed

Wu, Xiaocheng; Lang, Lingling; Ma, Wenjun; Song, Tie; Kang, Min; He, Jianfeng; Zhang, Yonghui; Lu, Liang; Lin, Hualiang; Ling, Li

2018-07-01

Dengue fever is an important infectious disease in Guangzhou, China; previous studies on the effects of weather factors on the incidence of dengue fever did not consider the linearity of the associations. This study evaluated the effects of daily mean temperature, relative humidity and rainfall on the incidence of dengue fever. A generalized additive model with splines smoothing function was performed to examine the effects of daily mean, minimum and maximum temperatures, relative humidity and rainfall on incidence of dengue fever during 2006-2014. Our analysis detected a non-linear effect of mean, minimum and maximum temperatures and relative humidity on dengue fever with the thresholds at 28°C, 23°C and 32°C for daily mean, minimum and maximum temperatures, 76% for relative humidity, respectively. Below the thresholds, there was a significant positive effect, the excess risk in dengue fever for each 1°C in the mean temperature at lag7-14days was 10.21%, (95% CI: 6.62% to 13.92%), 7.10% (95% CI: 4.99%, 9.26%) for 1°C increase in daily minimum temperature in lag 11days, and 2.27% (95% CI: 0.84%, 3.72%) for 1°C increase in daily maximum temperature in lag 10days; and each 1% increase in relative humidity of lag7-14days was associated with 1.95% (95% CI: 1.21% to 2.69%) in risk of dengue fever. Future prevention and control measures and epidemiology studies on dengue fever should consider these weather factors based on their exposure-response relationship. Copyright © 2018. Published by Elsevier B.V.

Device for monitoring cell voltage

DOEpatents

Doepke, Matthias [Garbsen, DE; Eisermann, Henning [Edermissen, DE

2012-08-21

A device for monitoring a rechargeable battery having a number of electrically connected cells includes at least one current interruption switch for interrupting current flowing through at least one associated cell and a plurality of monitoring units for detecting cell voltage. Each monitoring unit is associated with a single cell and includes a reference voltage unit for producing a defined reference threshold voltage and a voltage comparison unit for comparing the reference threshold voltage with a partial cell voltage of the associated cell. The reference voltage unit is electrically supplied from the cell voltage of the associated cell. The voltage comparison unit is coupled to the at least one current interruption switch for interrupting the current of at least the current flowing through the associated cell, with a defined minimum difference between the reference threshold voltage and the partial cell voltage.

Controlling marginally detached divertor plasmas

NASA Astrophysics Data System (ADS)

Eldon, D.; Kolemen, E.; Barton, J. L.; Briesemeister, A. R.; Humphreys, D. A.; Leonard, A. W.; Maingi, R.; Makowski, M. A.; McLean, A. G.; Moser, A. L.; Stangeby, P. C.

2017-06-01

A new control system at DIII-D has stabilized the inter-ELM detached divertor plasma state for H-mode in close proximity to the threshold for reattachment, thus demonstrating the ability to maintain detachment with minimal gas puffing. When the same control system was instead ordered to hold the plasma at the threshold (here defined as T e  =  5 eV near the divertor target plate), the resulting T e profiles separated into two groups with one group consistent with marginal detachment, and the other with marginal attachment. The plasma dithers between the attached and detached states when the control system attempts to hold at the threshold. The control system is upgraded from the one described in Kolemen et al (2015 J. Nucl. Mater. 463 1186) and it handles ELMing plasmas by using real time D α measurements to remove during-ELM slices from real time T e measurements derived from divertor Thomson scattering. The difference between measured and requested inter-ELM T e is passed to a PID (proportional-integral-derivative) controller to determine gas puff commands. While some degree of detachment is essential for the health of ITER’s divertor, more deeply detached plasmas have greater radiative losses and, at the extreme, confinement degradation, making it desirable to limit detachment to the minimum level needed to protect the target plate (Kolemen et al 2015 J. Nucl. Mater. 463 1186). However, the observed bifurcation in plasma conditions at the outer strike point with the ion B   ×  \

Influence of aging on thermal and vibratory thresholds of quantitative sensory testing.

PubMed

Lin, Yea-Huey; Hsieh, Song-Chou; Chao, Chi-Chao; Chang, Yang-Chyuan; Hsieh, Sung-Tsang

2005-09-01

Quantitative sensory testing has become a common approach to evaluate thermal and vibratory thresholds in various types of neuropathies. To understand the effect of aging on sensory perception, we measured warm, cold, and vibratory thresholds by performing quantitative sensory testing on a population of 484 normal subjects (175 males and 309 females), aged 48.61 +/- 14.10 (range 20-86) years. Sensory thresholds of the hand and foot were measured with two algorithms: the method of limits (Limits) and the method of level (Level). Thresholds measured by Limits are reaction-time-dependent, while those measured by Level are independent of reaction time. In addition, we explored (1) the correlations of thresholds between these two algorithms, (2) the effect of age on differences in thresholds between algorithms, and (3) differences in sensory thresholds between the two test sites. Age was consistently and significantly correlated with sensory thresholds of all tested modalities measured by both algorithms on multivariate regression analysis compared with other factors, including gender, body height, body weight, and body mass index. When thresholds were plotted against age, slopes differed between sensory thresholds of the hand and those of the foot: for the foot, slopes were steeper compared with those for the hand for each sensory modality. Sensory thresholds of both test sites measured by Level were highly correlated with those measured by Limits, and thresholds measured by Limits were higher than those measured by Level. Differences in sensory thresholds between the two algorithms were also correlated with age: thresholds of the foot were higher than those of the hand for each sensory modality. This difference in thresholds (measured with both Level and Limits) between the hand and foot was also correlated with age. These findings suggest that age is the most significant factor in determining sensory thresholds compared with the other factors of gender and anthropometric parameters, and this provides a foundation for investigating the neurobiologic significance of aging on the processing of sensory stimuli.

Parameter estimation of history-dependent leaky integrate-and-fire neurons using maximum-likelihood methods

PubMed Central

Dong, Yi; Mihalas, Stefan; Russell, Alexander; Etienne-Cummings, Ralph; Niebur, Ernst

2012-01-01

When a neuronal spike train is observed, what can we say about the properties of the neuron that generated it? A natural way to answer this question is to make an assumption about the type of neuron, select an appropriate model for this type, and then to choose the model parameters as those that are most likely to generate the observed spike train. This is the maximum likelihood method. If the neuron obeys simple integrate and fire dynamics, Paninski, Pillow, and Simoncelli (2004) showed that its negative log-likelihood function is convex and that its unique global minimum can thus be found by gradient descent techniques. The global minimum property requires independence of spike time intervals. Lack of history dependence is, however, an important constraint that is not fulfilled in many biological neurons which are known to generate a rich repertoire of spiking behaviors that are incompatible with history independence. Therefore, we expanded the integrate and fire model by including one additional variable, a variable threshold (Mihalas & Niebur, 2009) allowing for history-dependent firing patterns. This neuronal model produces a large number of spiking behaviors while still being linear. Linearity is important as it maintains the distribution of the random variables and still allows for maximum likelihood methods to be used. In this study we show that, although convexity of the negative log-likelihood is not guaranteed for this model, the minimum of the negative log-likelihood function yields a good estimate for the model parameters, in particular if the noise level is treated as a free parameter. Furthermore, we show that a nonlinear function minimization method (r-algorithm with space dilation) frequently reaches the global minimum. PMID:21851282

Reexamining the minimum viable population concept for long-lived species.

PubMed

Shoemaker, Kevin T; Breisch, Alvin R; Jaycox, Jesse W; Gibbs, James P

2013-06-01

For decades conservation biologists have proposed general rules of thumb for minimum viable population size (MVP); typically, they range from hundreds to thousands of individuals. These rules have shifted conservation resources away from small and fragmented populations. We examined whether iteroparous, long-lived species might constitute an exception to general MVP guidelines. On the basis of results from a 10-year capture-recapture study in eastern New York (U.S.A.), we developed a comprehensive demographic model for the globally threatened bog turtle (Glyptemys muhlenbergii), which is designated as endangered by the IUCN in 2011. We assessed population viability across a wide range of initial abundances and carrying capacities. Not accounting for inbreeding, our results suggest that bog turtle colonies with as few as 15 breeding females have >90% probability of persisting for >100 years, provided vital rates and environmental variance remain at currently estimated levels. On the basis of our results, we suggest that MVP thresholds may be 1-2 orders of magnitude too high for many long-lived organisms. Consequently, protection of small and fragmented populations may constitute a viable conservation option for such species, especially in a regional or metapopulation context. © 2013 Society for Conservation Biology.

Contribution of piezometric measurement on knowledge and management of low water levels

NASA Astrophysics Data System (ADS)

Bessiere, Hélène; Stollsteiner, Philippe; Allier, Delphine; Nicolas, Jérôme; Gourcy, Laurence

2014-05-01

This article is based on a BRGM study on piezometric indicators, threshold values of discharges and groundwater levels for the assessment of potentially pumpable volumes of chalky watersheds. A method for estimating low water levels from groundwater levels is presented from three examples of chalk aquifer; the first one is located in Picardy and the two other in the Champagne Ardennes region. Piezometers with "annual" cycles, used in these examples, are supposed to be representative of the aquifer hydrodynamics. The analysis leads to relatively precise and satisfactory relationships between groundwater levels and observed discharges for this chalky context. These relationships may be useful for monitoring, validation, extension or reconstruction of the low water flow. On the one hand, they allow defining the piezometric levels corresponding to the different alert thresholds of river discharges. On the other hand, they clarify the distribution of low water flow from runoff or the draining of the aquifer. Finally, these correlations give an assessment of the minimum flow for the coming weeks using of the rate of draining of the aquifer. Nevertheless the use of these correlations does not allow to optimize the value of pumpable volumes because it seems to be difficult to integrate the amount of the effective rainfall that may occur during the draining period. In addition, these relationships cannot be exploited for multi-annual cycle systems. In these cases, the solution seems to lie on the realization of a rainfall-runoff-piezometric level model. Therefore, two possibilities are possible. The first one is to achieve each year, on a given date, a forecast for the days or months to come with various frequential distributions rainfalls. However, the forecast must be reiterated each year depending on climatic conditions. The principle of the second method is to simulate forecasts for different rainfall intensities and following different initial conditions. The results are presented in chart form. In addition, this last method is currently tested for the problem of floods by groundwater level rise.

Minimum Requirements for Taxicab Security Cameras.

PubMed

Zeng, Shengke; Amandus, Harlan E; Amendola, Alfred A; Newbraugh, Bradley H; Cantis, Douglas M; Weaver, Darlene

2014-07-01

The homicide rate of taxicab-industry is 20 times greater than that of all workers. A NIOSH study showed that cities with taxicab-security cameras experienced significant reduction in taxicab driver homicides. Minimum technical requirements and a standard test protocol for taxicab-security cameras for effective taxicab-facial identification were determined. The study took more than 10,000 photographs of human-face charts in a simulated-taxicab with various photographic resolutions, dynamic ranges, lens-distortions, and motion-blurs in various light and cab-seat conditions. Thirteen volunteer photograph-evaluators evaluated these face photographs and voted for the minimum technical requirements for taxicab-security cameras. Five worst-case scenario photographic image quality thresholds were suggested: the resolution of XGA-format, highlight-dynamic-range of 1 EV, twilight-dynamic-range of 3.3 EV, lens-distortion of 30%, and shutter-speed of 1/30 second. These minimum requirements will help taxicab regulators and fleets to identify effective taxicab-security cameras, and help taxicab-security camera manufacturers to improve the camera facial identification capability.

Rate-compatible protograph LDPC code families with linear minimum distance

NASA Technical Reports Server (NTRS)

Divsalar, Dariush (Inventor); Dolinar, Jr., Samuel J (Inventor); Jones, Christopher R. (Inventor)

2012-01-01

Digital communication coding methods are shown, which generate certain types of low-density parity-check (LDPC) codes built from protographs. A first method creates protographs having the linear minimum distance property and comprising at least one variable node with degree less than 3. A second method creates families of protographs of different rates, all having the linear minimum distance property, and structurally identical for all rates except for a rate-dependent designation of certain variable nodes as transmitted or non-transmitted. A third method creates families of protographs of different rates, all having the linear minimum distance property, and structurally identical for all rates except for a rate-dependent designation of the status of certain variable nodes as non-transmitted or set to zero. LDPC codes built from the protographs created by these methods can simultaneously have low error floors and low iterative decoding thresholds, and families of such codes of different rates can be decoded efficiently using a common decoding architecture.

A ram-pressure threshold for star formation

NASA Astrophysics Data System (ADS)

Whitworth, A. P.

2016-05-01

In turbulent fragmentation, star formation occurs in condensations created by converging flows. The condensations must be sufficiently massive, dense and cool to be gravitationally unstable, so that they start to contract; and they must then radiate away thermal energy fast enough for self-gravity to remain dominant, so that they continue to contract. For the metallicities and temperatures in local star-forming clouds, this second requirement is only met robustly when the gas couples thermally to the dust, because this delivers the capacity to radiate across the full bandwidth of the continuum, rather than just in a few discrete spectral lines. This translates into a threshold for vigorous star formation, which can be written as a minimum ram pressure PCRIT ˜ 4 × 10-11 dyne. PCRIT is independent of temperature, and corresponds to flows with molecular hydrogen number density n_{{H_2.FLOW}} and velocity vFLOW satisfying n_{{H_2.FLOW}} v_{FLOW}^2≳ 800 cm^{-3} (km s^{-1})^2. This in turn corresponds to a minimum molecular hydrogen column density for vigorous star formation, N_{{H_2.CRIT}} ˜ 4 × 10^{21} cm^{-2} (ΣCRIT ˜ 100 M⊙ pc-2), and a minimum visual extinction AV, CRIT ˜ 9 mag. The characteristic diameter and line density for a star-forming filament when this threshold is just exceeded - a sweet spot for local star formation regions - are 2RFIL ˜ 0.1 pc and μFIL ˜ 13 M⊙ pc-2. The characteristic diameter and mass for a prestellar core condensing out of such a filament are 2RCORE ˜ 0.1 pc and MCORE ˜ 1 M⊙. We also show that fragmentation of a shock-compressed layer is likely to commence while the convergent flows creating the layer are still ongoing, and we stress that, under this circumstance, the phenomenology and characteristic scales for fragmentation of the layer are fundamentally different from those derived traditionally for pre-existing layers.

42 CFR 412.348 - Exception payments.

Code of Federal Regulations, 2010 CFR

2010-10-01

... beginning on or after October 1, 1991 and before October 1, 2001. (c) Minimum payment level by class of hospital. (1) CMS establishes a minimum payment level by class of hospital. The minimum payment level for a hospital will equal a fixed percentage of the hospital's capital-related costs. The minimum payment levels...

12 CFR 263.82 - Establishment of minimum capital levels.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 12 Banks and Banking 3 2010-01-01 2010-01-01 false Establishment of minimum capital levels. 263.82... Maintain Adequate Capital § 263.82 Establishment of minimum capital levels. The Board has established minimum capital levels for state member banks and bank holding companies in its Capital Adequacy...

75 FR 38423 - Minimum Levels of Financial Responsibility for Motor Carriers

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-02

... No. FMCSA-2006-26262] RIN 2126-AB05 Minimum Levels of Financial Responsibility for Motor Carriers... amends its regulations concerning minimum levels of financial responsibility for motor carriers to allow... principal place of business. This final rule does not change the required minimum levels of financial...

Safety of American Heart Association-recommended minimum exercise for desmosomal mutation carriers.

PubMed

Sawant, Abhishek C; Te Riele, Anneline S J M; Tichnell, Crystal; Murray, Brittney; Bhonsale, Aditya; Tandri, Harikrishna; Judge, Daniel P; Calkins, Hugh; James, Cynthia A

2016-01-01

Endurance exercise is associated with adverse outcomes in patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). Exercise recommendations for family members remain undetermined. The purposes of this study were to determine if (1) endurance exercise (Bethesda class C) and exercise intensity (metabolic equivalent hours per year [MET-Hr/year]) increase the likelihood of fulfilling 2010 Task Force Criteria and ventricular arrhythmias/implantable cardioverter-defibrillator shock (ventricular tachycardia/ventricular fibrillation [VT/VF]), and (2) exercise restriction to the American Heart Association (AHA)-recommended minimum for healthy adults is associated with favorable outcomes of at-risk family members. Twenty-eight family members of 10 probands inheriting a PKP2 mutation were interviewed about exercise from age 10. Exercise threshold to maintain overall health was based on the 2007 AHA guidelines of a minimum 390 to 650 MET-Hr/year. After adjustment for age, sex, and family membership, both participation in endurance athletics (odds ratio [OR] 7.4, P = .03) and higher-intensity exercise (OR = 4.2, P = .004) were associated with diagnosis (n = 13). Endurance athletes were also significantly more likely to develop VT/VF (n = 6, P = .02). Family members who restricted exercise at or below the upper bound of the AHA goal (≤650 MET-Hr/year) were significantly less likely to be diagnosed (OR = 0.07, P = .002) and had no VT/VF. At diagnosis and first VT/VF, family members had accumulated 2.8-fold (P = .002) and 3.5-fold (P = .03), respectively, greater MET-Hr exercise than the AHA-recommended minimum. Those who developed VT/VF had performed particularly high-intensity exercise in adolescence compared to unaffected family members (age 10-14: P = .04; age 14-19: P = .02). The results of this study suggest restricting unaffected desmosomal mutation carriers from endurance and high-intensity athletics but potentially not from AHA-recommended minimum levels of exercise for healthy adults. Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

On the Relationship Between Spotless Days and the Sunspot Cycle: A Supplement

NASA Technical Reports Server (NTRS)

Wilson, Robert M.; Hathaway, David H.

2006-01-01

This study provides supplemental material to an earlier study concerning the relationship between spotless days and the sunspot cycle. Our previous study, Technical Publication (TP)-2005-213608 determined the timing and size of sunspot minimum and maximum for the new sunspot cycle, relative to the occurrence of the first spotless day during the declining phase of the old sunspot cycle and the last spotless day during the rising portion of the new cycle. Because the number of spotless days (NSD) rapidly increases as the cycle nears sunspot minimum and rapidly decreases thereafter, the size and timing of sunspot minimum and maximum might be more accurately determined using a higher threshold for comparison, rather than using the first and last spotless day occurrences. It is this aspect that is investigated more thoroughly in this TP.

A de-noising method using the improved wavelet threshold function based on noise variance estimation

NASA Astrophysics Data System (ADS)

Liu, Hui; Wang, Weida; Xiang, Changle; Han, Lijin; Nie, Haizhao

2018-01-01

The precise and efficient noise variance estimation is very important for the processing of all kinds of signals while using the wavelet transform to analyze signals and extract signal features. In view of the problem that the accuracy of traditional noise variance estimation is greatly affected by the fluctuation of noise values, this study puts forward the strategy of using the two-state Gaussian mixture model to classify the high-frequency wavelet coefficients in the minimum scale, which takes both the efficiency and accuracy into account. According to the noise variance estimation, a novel improved wavelet threshold function is proposed by combining the advantages of hard and soft threshold functions, and on the basis of the noise variance estimation algorithm and the improved wavelet threshold function, the research puts forth a novel wavelet threshold de-noising method. The method is tested and validated using random signals and bench test data of an electro-mechanical transmission system. The test results indicate that the wavelet threshold de-noising method based on the noise variance estimation shows preferable performance in processing the testing signals of the electro-mechanical transmission system: it can effectively eliminate the interference of transient signals including voltage, current, and oil pressure and maintain the dynamic characteristics of the signals favorably.

Impact of intrapatient variability (IPV) in tacrolimus trough levels on long-term renal transplant function: multicentre collaborative retrospective cohort study protocol

PubMed Central

Goldsmith, Petra M; Bottomley, Matthew J; Okechukwu, Okidi; Ross, Victoria C; Ghita, Ryan; Wandless, David; Falconer, Stuart J; Papachristos, Stavros; Nash, Philip; Androshchuk, Vitaliy; Clancy, Marc

2017-01-01

Introduction High intrapatient variability (IPV) in tacrolimus trough levels has been shown to be associated with higher rates of renal transplant failure. There is no consensus on what level of IPV constitutes a risk of graft loss. The establishment of such a threshold could help to guide clinicians in identifying at-risk patients to receive targeted interventions to improve IPV and thus outcomes. Methods and analysis A multicentre Transplant Audit Collaborative has been established to conduct a retrospective study examining tacrolimus IPV and renal transplant outcomes. Patients in receipt of a renal transplant at participating centres between 2009 and 2014 and fulfilling the inclusion criteria will be included in the study. The aim is to recruit a minimum of 1600 patients with follow-up spanning at least 2 years in order to determine a threshold IPV above which a renal transplant recipient would be considered at increased risk of graft loss. The study also aims to determine any national or regional trends in IPV and any demographic associations. Ethics and dissemination Consent will not be sought from patients whose data are used in this study as no additional procedures or information will be required from participants beyond that which would normally take place as part of clinical care. The study will be registered locally in each participating centre in line with local research and development protocols. It is anticipated that the results of this audit will be disseminated locally, in participating NHS Trusts, through national and international meetings and publications in peer-reviewed journals. PMID:28756385

A brief peripheral motion contrast threshold test predicts older drivers' hazardous behaviors in simulated driving.

PubMed

Henderson, Steven; Woods-Fry, Heather; Collin, Charles A; Gagnon, Sylvain; Voloaca, Misha; Grant, John; Rosenthal, Ted; Allen, Wade

2015-05-01

Our research group has previously demonstrated that the peripheral motion contrast threshold (PMCT) test predicts older drivers' self-report accident risk, as well as simulated driving performance. However, the PMCT is too lengthy to be a part of a battery of tests to assess fitness to drive. Therefore, we have developed a new version of this test, which takes under two minutes to administer. We assessed the motion contrast thresholds of 24 younger drivers (19-32) and 25 older drivers (65-83) with both the PMCT-10min and the PMCT-2min test and investigated if thresholds were associated with measures of simulated driving performance. Younger participants had significantly lower motion contrast thresholds than older participants and there were no significant correlations between younger participants' thresholds and any measures of driving performance. The PMCT-10min and the PMCT-2min thresholds of older drivers' predicted simulated crash risk, as well as the minimum distance of approach to all hazards. This suggests that our tests of motion processing can help predict the risk of collision or near collision in older drivers. Thresholds were also correlated with the total lane deviation time, suggesting a deficiency in processing of peripheral flow and delayed detection of adjacent cars. The PMCT-2min is an improved version of a previously validated test, and it has the potential to help assess older drivers' fitness to drive. Copyright © 2015 Elsevier Ltd. All rights reserved.

New analytical model for the ozone electronic ground state potential surface and accurate ab initio vibrational predictions at high energy range.

PubMed

Tyuterev, Vladimir G; Kochanov, Roman V; Tashkun, Sergey A; Holka, Filip; Szalay, Péter G

2013-10-07

An accurate description of the complicated shape of the potential energy surface (PES) and that of the highly excited vibration states is of crucial importance for various unsolved issues in the spectroscopy and dynamics of ozone and remains a challenge for the theory. In this work a new analytical representation is proposed for the PES of the ground electronic state of the ozone molecule in the range covering the main potential well and the transition state towards the dissociation. This model accounts for particular features specific to the ozone PES for large variations of nuclear displacements along the minimum energy path. The impact of the shape of the PES near the transition state (existence of the "reef structure") on vibration energy levels was studied for the first time. The major purpose of this work was to provide accurate theoretical predictions for ozone vibrational band centres at the energy range near the dissociation threshold, which would be helpful for understanding the very complicated high-resolution spectra and its analyses currently in progress. Extended ab initio electronic structure calculations were carried out enabling the determination of the parameters of a minimum energy path PES model resulting in a new set of theoretical vibrational levels of ozone. A comparison with recent high-resolution spectroscopic data on the vibrational levels gives the root-mean-square deviations below 1 cm(-1) for ozone band centres up to 90% of the dissociation energy. New ab initio vibrational predictions represent a significant improvement with respect to all previously available calculations.

Temporal resolution in children.

PubMed

Wightman, F; Allen, P; Dolan, T; Kistler, D; Jamieson, D

1989-06-01

The auditory temporal resolving power of young children was measured using an adaptive forced-choice psychophysical paradigm that was disguised as a video game. 20 children between 3 and 7 years of age and 5 adults were asked to detect the presence of a temporal gap in a burst of half-octave-band noise at band center frequencies of 400 and 2,000 Hz. The minimum detectable gap (gap threshold) was estimated adaptively in 20-trial runs. The mean gap thresholds in the 400-Hz condition were higher for the younger children than for the adults, with the 3-year-old children producing the highest thresholds. Gap thresholds in the 2,000-Hz condition were generally lower than in the 400-Hz condition and showed a similar age effect. All the individual adaptive runs were "adult-like," suggesting that the children were generally attentive to the task during each run. However, the variability of threshold estimates from run to run was substantial, especially in the 3-5-year-old children. Computer simulations suggested that this large within-subjects variability could have resulted from frequent, momentary lapses of attention, which would lead to "guessing" on a substantial portion of the trials.

Estimating phonation threshold pressure.

PubMed

Fisher, K V; Swank, P R

1997-10-01

Phonation threshold pressure (PTP) is the minimum subglottal pressure required to initiate vocal fold oscillation. Although potentially useful clinically, PTP is difficult to estimate noninvasively because of limitations to vocal motor control near the threshold of soft phonation. Previous investigators observed, for example, that trained subjects were unable to produce flat, consistent oral pressure peaks during/pae/syllable strings when they attempted to phonate as softly as possible (Verdolini-Marston, Titze, & Druker, 1990). The present study aimed to determine if nasal airflow or vowel context affected phonation threshold pressure as estimated from oral pressure (Smitheran & Hixon, 1981) in 5 untrained female speakers with normal velopharyngeal and voice function. Nasal airflow during /p/occlusion was observed for 3 of 5 participants when they attempted to phonate near threshold pressure. When the nose was occluded, nasal airflow was reduced or eliminated during /p/;however, individuals then evidenced compensatory changes in glottal adduction and/or respiratory effort that may be expected to alter PTP estimates. Results demonstrate the importance of monitoring nasal flow (or the flow zero point in undivided masks) when obtaining PTP measurements noninvasively. Results also highlight the need to pursue improved methods for noninvasive estimation of PTP.

Event-related potential measures of gap detection threshold during natural sleep.

PubMed

Muller-Gass, Alexandra; Campbell, Kenneth

2014-08-01

The minimum time interval between two stimuli that can be reliably detected is called the gap detection threshold. The present study examines whether an unconscious state, natural sleep affects the gap detection threshold. Event-related potentials were recorded in 10 young adults while awake and during all-night sleep to provide an objective estimate of this threshold. These subjects were presented with 2, 4, 8 or 16ms gaps occurring in 1.5 duration white noise. During wakefulness, a significant N1 was elicited for the 8 and 16ms gaps. N1 was difficult to observe during stage N2 sleep, even for the longest gap. A large P2 was however elicited and was significant for the 8 and 16ms gaps. Also, a later, very large N350 was elicited by the 16ms gap. An N1 and P2 was significant only for the 16ms gap during REM sleep. ERPs to gaps occurring in noise segments can therefore be successfully elicited during natural sleep. The gap detection threshold is similar in the waking and sleeping states. Crown Copyright © 2014. Published by Elsevier Ireland Ltd. All rights reserved.

Temporal Information Processing as a Basis for Auditory Comprehension: Clinical Evidence from Aphasic Patients

ERIC Educational Resources Information Center

Oron, Anna; Szymaszek, Aneta; Szelag, Elzbieta

2015-01-01

Background: Temporal information processing (TIP) underlies many aspects of cognitive functions like language, motor control, learning, memory, attention, etc. Millisecond timing may be assessed by sequencing abilities, e.g. the perception of event order. It may be measured with auditory temporal-order-threshold (TOT), i.e. a minimum time gap…

47 CFR 15.717 - TVBDs that rely on spectrum sensing.

Code of Federal Regulations, 2013 CFR

2013-10-01

... over a 100 kHz bandwidth; (C) Low power auxiliary, including wireless microphone, signals: -107 dBm, averaged over a 200 kHz bandwidth. (ii) The detection thresholds are referenced to an omnidirectional receive antenna with a gain of 0 dBi. If a receive antenna with a minimum directional gain of less than 0...

47 CFR 15.717 - TVBDs that rely on spectrum sensing.

Code of Federal Regulations, 2014 CFR

2014-10-01

... over a 100 kHz bandwidth; (C) Low power auxiliary, including wireless microphone, signals: -107 dBm, averaged over a 200 kHz bandwidth. (ii) The detection thresholds are referenced to an omnidirectional receive antenna with a gain of 0 dBi. If a receive antenna with a minimum directional gain of less than 0...

47 CFR 15.717 - TVBDs that rely on spectrum sensing.

Code of Federal Regulations, 2011 CFR

2011-10-01

... over a 100 kHz bandwidth; (C) Low power auxiliary, including wireless microphone, signals: -107 dBm, averaged over a 200 kHz bandwidth. (ii) The detection thresholds are referenced to an omnidirectional receive antenna with a gain of 0 dBi. If a receive antenna with a minimum directional gain of less than 0...

47 CFR 15.717 - TVBDs that rely on spectrum sensing.

Code of Federal Regulations, 2012 CFR

2012-10-01

... over a 100 kHz bandwidth; (C) Low power auxiliary, including wireless microphone, signals: -107 dBm, averaged over a 200 kHz bandwidth. (ii) The detection thresholds are referenced to an omnidirectional receive antenna with a gain of 0 dBi. If a receive antenna with a minimum directional gain of less than 0...

Temperature thresholds related to flight of Dendroctonus frontalis Zimm. (Col.: Scolytidae)

Treesearch

John C. Moser; William A. Thompson

1986-01-01

We have plotted the complete range of flight temperatures for the southern pine beele, the first such figures for any bark beetle.The optimum flight temperature was about 27oC.Observed minimum and maximum flight temperatures for southern pine beetle were 6.7oC and 36.7oC, respectively. Projected...

Reliability, standard error, and minimum detectable change of clinical pressure pain threshold testing in people with and without acute neck pain.

PubMed

Walton, David M; Macdermid, Joy C; Nielson, Warren; Teasell, Robert W; Chiasson, Marco; Brown, Lauren

2011-09-01

Clinical measurement. To evaluate the intrarater, interrater, and test-retest reliability of an accessible digital algometer, and to determine the minimum detectable change in normal healthy individuals and a clinical population with neck pain. Pressure pain threshold testing may be a valuable assessment and prognostic indicator for people with neck pain. To date, most of this research has been completed using algometers that are too resource intensive for routine clinical use. Novice raters (physiotherapy students or clinical physiotherapists) were trained to perform algometry testing over 2 clinically relevant sites: the angle of the upper trapezius and the belly of the tibialis anterior. A convenience sample of normal healthy individuals and a clinical sample of people with neck pain were tested by 2 different raters (all participants) and on 2 different days (healthy participants only). Intraclass correlation coefficient (ICC), standard error of measurement, and minimum detectable change were calculated. A total of 60 healthy volunteers and 40 people with neck pain were recruited. Intrarater reliability was almost perfect (ICC = 0.94-0.97), interrater reliability was substantial to near perfect (ICC = 0.79-0.90), and test-retest reliability was substantial (ICC = 0.76-0.79). Smaller change was detectable in the trapezius compared to the tibialis anterior. This study provides evidence that novice raters can perform digital algometry with adequate reliability for research and clinical use in people with and without neck pain.

Detection of hail signatures from single-polarization C-band radar reflectivity

NASA Astrophysics Data System (ADS)

Kunz, Michael; Kugel, Petra I. S.

2015-02-01

Five different criteria that estimate hail signatures from single-polarization radar data are statistically evaluated over a 15-year period by categorical verification against loss data provided by a building insurance company. The criteria consider different levels or thresholds of radar reflectivity, some of them complemented by estimates of the 0 °C level or cloud top temperature. Applied to reflectivity data from a single C-band radar in southwest Germany, it is found that all criteria are able to reproduce most of the past damage-causing hail events. However, the criteria substantially overestimate hail occurrence by up to 80%, mainly due to the verification process using damage data. Best results in terms of highest Heidke Skill Score HSS or Critical Success Index CSI are obtained for the Hail Detection Algorithm (HDA) and the Probability of Severe Hail (POSH). Radar-derived hail probability shows a high spatial variability with a maximum on the lee side of the Black Forest mountains and a minimum in the broad Rhine valley.

On thermonuclear ignition criterion at the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, Baolian; Kwan, Thomas J. T.; Wang, Yi-Ming

2014-10-15

Sustained thermonuclear fusion at the National Ignition Facility remains elusive. Although recent experiments approached or exceeded the anticipated ignition thresholds, the nuclear performance of the laser-driven capsules was well below predictions in terms of energy and neutron production. Such discrepancies between expectations and reality motivate a reassessment of the physics of ignition. We have developed a predictive analytical model from fundamental physics principles. Based on the model, we obtained a general thermonuclear ignition criterion in terms of the areal density and temperature of the hot fuel. This newly derived ignition threshold and its alternative forms explicitly show the minimum requirementsmore » of the hot fuel pressure, mass, areal density, and burn fraction for achieving ignition. Comparison of our criterion with existing theories, simulations, and the experimental data shows that our ignition threshold is more stringent than those in the existing literature and that our results are consistent with the experiments.« less

Impact response of graphite-epoxy flat laminates using projectiles that simulate aircraft engine encounters

NASA Technical Reports Server (NTRS)

Preston, J. L., Jr.; Cook, T. S.

1975-01-01

An investigation of the response of a graphite-epoxy material to foreign object impact was made by impacting spherical projectiles of gelatin, ice, and steel normally on flat panels. The observed damage was classified as transverse (stress wave delamination and cracking), penetrative, or structural (gross failure): the minimum, or threshold, velocity to cause each class of damage was established as a function of projectile characteristics. Steel projectiles had the lowest transverse damage threshold, followed by gelatin and ice. Making use of the threshold velocities and assuming that the normal component of velocity produces the damage in nonnormal impacts, a set of impact angles and velocities was established for each projectile material which would result in damage to composite fan blades. Analysis of the operating parameters of a typical turbine fan blade shows that small steel projectiles are most likely to cause delamination and penetration damage to unprotected graphite-epoxy composite fan blades.

Extended performance gas Cherenkov detector for gamma-ray detection in high-energy density experiments.

PubMed

Herrmann, H W; Kim, Y H; Young, C S; Fatherley, V E; Lopez, F E; Oertel, J A; Malone, R M; Rubery, M S; Horsfield, C J; Stoeffl, W; Zylstra, A B; Shmayda, W T; Batha, S H

2014-11-01

A new Gas Cherenkov Detector (GCD) with low-energy threshold and high sensitivity, currently known as Super GCD (or GCD-3 at OMEGA), is being developed for use at the OMEGA Laser Facility and the National Ignition Facility (NIF). Super GCD is designed to be pressurized to ≤400 psi (absolute) and uses all metal seals to allow the use of fluorinated gases inside the target chamber. This will allow the gamma energy threshold to be run as low at 1.8 MeV with 400 psi (absolute) of C2F6, opening up a new portion of the gamma ray spectrum. Super GCD operating at 20 cm from TCC will be ∼400 × more efficient at detecting DT fusion gammas at 16.7 MeV than the Gamma Reaction History diagnostic at NIF (GRH-6m) when operated at their minimum thresholds.

Typical performance of approximation algorithms for NP-hard problems

NASA Astrophysics Data System (ADS)

Takabe, Satoshi; Hukushima, Koji

2016-11-01

Typical performance of approximation algorithms is studied for randomized minimum vertex cover problems. A wide class of random graph ensembles characterized by an arbitrary degree distribution is discussed with the presentation of a theoretical framework. Herein, three approximation algorithms are examined: linear-programming relaxation, loopy-belief propagation, and the leaf-removal algorithm. The former two algorithms are analyzed using a statistical-mechanical technique, whereas the average-case analysis of the last one is conducted using the generating function method. These algorithms have a threshold in the typical performance with increasing average degree of the random graph, below which they find true optimal solutions with high probability. Our study reveals that there exist only three cases, determined by the order of the typical performance thresholds. In addition, we provide some conditions for classification of the graph ensembles and demonstrate explicitly some examples for the difference in thresholds.

Incomplete Spontaneous Recovery from Airway Obstruction During Inhaled Anesthesia Induction: A Computational Simulation.

PubMed

Kuo, Alexander S; Vijjeswarapu, Mary A; Philip, James H

2016-03-01

Inhaled induction with spontaneous respiration is a technique used for difficult airways. One of the proposed advantages is if airway patency is lost, the anesthetic agent will spontaneously redistribute until anesthetic depth is reduced and airway patency can be recovered. There are little and conflicting clinical or experimental data regarding the kinetics of this anesthetic technique. We used computer simulation to investigate this situation. We used GasMan, a computer simulation of inhaled anesthetic kinetics. For each simulation, alveolar ventilation was initiated with a set anesthetic induction concentration. When the vessel-rich group level reached the simulation specified airway obstruction threshold, alveolar ventilation was set at 0 to simulate complete airway obstruction. The time until the vessel-rich group anesthetic level decreased below the airway obstruction threshold was designated time to spontaneous recovery. We varied the parameters for each simulation, exploring the use of sevoflurane and halothane, airway obstruction threshold from 0.5 to 2 minimum alveolar concentration (MAC), anesthetic induction concentration 2 to 4 MAC sevoflurane and 4 to 6 MAC halothane, cardiac output 2.5 to 10 L/min, functional residual capacity 1.5 to 3.5 L, and relative vessel-rich group perfusion 67% to 85%. In each simulation, there were 3 general phases: anesthetic wash-in, obstruction and overshoot, and then slow redistribution. During the first 2 phases, there was a large gradient between the alveolar and vessel-rich group. Alveolar do not reflect vessel-rich group anesthetic levels until the late third phase. Time to spontaneous recovery varied between 35 and 749 seconds for sevoflurane and 13 and 222 seconds for halothane depending on the simulation parameters. Halothane had a faster time to spontaneous recovery because of the lower alveolar gradient and less overshoot of the vessel-rich group, not faster redistribution. Higher airway obstruction thresholds, decreased anesthetic induction, and higher cardiac output reduced time to spontaneous recovery. To a lesser effect, decreased functional residual capacity and the decreased relative vessel-rich groups' perfusion also reduced the time to spontaneous recovery. Spontaneous recovery after complete airway obstruction during inhaled induction is plausible, but the recovery time is highly variable and depends on the clinical and physiologic situation. These results emphasize that induction is a non-steady-state situation, thus effect-site anesthetic levels should be modeled in future research, not alveolar concentration. Finally, this study provides an example of using computer simulation to explore situations that are difficult to investigate clinically.

Investigating the Sensitivity of Model Intraseasonal Variability to Minimum Entrainment

NASA Astrophysics Data System (ADS)

Hannah, W. M.; Maloney, E. D.

2008-12-01

Previous studies have shown that using a Relaxed Arakawa-Schubert (RAS) convective parameterization with appropriate convective triggers and assumptions about rain re-evaporation produces realistic intraseasonal variability. RAS represents convection with an ensemble of clouds detraining at different heights, each with different entrainment rate, the highest clouds having the lowest entrainment rates. If tropospheric temperature gradients are weak and boundary layer moist static energy is relatively constant, then by limiting the minimum entrainment rate deep convection is suppressed in the presence of dry tropospheric air. This allows moist static energy to accumulate and be discharged during strong intraseasonal convective events, which is consistent with the discharge/recharge paradigm. This study will examine the sensitivity of intra-seasonal variability to changes in minimum entrainment rate in the NCAR-CAM3 with the RAS scheme. Simulations using several minimum entrainment rate thresholds will be investigated. A frequency-wavenumber analysis will show the improvement of the MJO signal as minimum entrainment rate is increased. The spatial and vertical structure of MJO-like disturbances will be examined, including an analysis of the time evolution of vertical humidity distribution for each simulation. Simulated results will be compared to observed MJO events in NCEP-1 reanalysis and CMAP precipitation.

Investigation of a New Handover Approach in LTE and WiMAX

PubMed Central

Hindia, Mohammad Nour; Reza, Ahmed Wasif; Noordin, Kamarul Ariffin

2014-01-01

Nowadays, one of the most important challenges in heterogeneous networks is the connection consistency between the mobile station and the base stations. Furthermore, along the roaming process between the mobile station and the base station, the system performance degrades significantly due to the interferences from neighboring base stations, handovers to inaccurate base station and inappropriate technology selection. In this paper, several algorithms are proposed to improve mobile station performance and seamless mobility across the long-term evolution (LTE) and Worldwide Interoperability for Microwave Access (WiMAX) technologies, along with a minimum number of redundant handovers. Firstly, the enhanced global positioning system (GPS) and the novel received signal strength (RSS) prediction approaches are suggested to predict the target base station accurately. Then, the multiple criteria with two thresholds algorithm is proposed to prioritize the selection between LTE and WiMAX as the target technology. In addition, this study also covers the intercell and cochannel interference reduction by adjusting the frequency reuse ratio 3 (FRR3) to work with LTE and WiMAX. The obtained results demonstrate high next base station prediction efficiency and high accuracy for both horizontal and vertical handovers. Moreover, the received signal strength is kept at levels higher than the threshold, while maintaining low connection cost and delay within acceptable levels. In order to highlight the combination of the proposed algorithms' performance, it is compared with the existing RSS and multiple criteria handover decision algorithms. PMID:25379524

Investigation of a new handover approach in LTE and WiMAX.

PubMed

Hindia, Mohammad Nour; Reza, Ahmed Wasif; Noordin, Kamarul Ariffin

2014-01-01

Nowadays, one of the most important challenges in heterogeneous networks is the connection consistency between the mobile station and the base stations. Furthermore, along the roaming process between the mobile station and the base station, the system performance degrades significantly due to the interferences from neighboring base stations, handovers to inaccurate base station and inappropriate technology selection. In this paper, several algorithms are proposed to improve mobile station performance and seamless mobility across the long-term evolution (LTE) and Worldwide Interoperability for Microwave Access (WiMAX) technologies, along with a minimum number of redundant handovers. Firstly, the enhanced global positioning system (GPS) and the novel received signal strength (RSS) prediction approaches are suggested to predict the target base station accurately. Then, the multiple criteria with two thresholds algorithm is proposed to prioritize the selection between LTE and WiMAX as the target technology. In addition, this study also covers the intercell and cochannel interference reduction by adjusting the frequency reuse ratio 3 (FRR3) to work with LTE and WiMAX. The obtained results demonstrate high next base station prediction efficiency and high accuracy for both horizontal and vertical handovers. Moreover, the received signal strength is kept at levels higher than the threshold, while maintaining low connection cost and delay within acceptable levels. In order to highlight the combination of the proposed algorithms' performance, it is compared with the existing RSS and multiple criteria handover decision algorithms.

Electrically evoked compound action potential amplitude growth functions and HiResolution programming levels in pediatric CII implant subjects.

PubMed

Eisen, Marc D; Franck, Kevin H

2004-12-01

To characterize the amplitude growth functions of the electrically evoked compound action potential (ECAP) in pediatric subjects implanted with the Clarion HiFocus electrode array with respect to electrode position and the presence or absence of a Silastic positioner. Electrophysiologic growth function data are compared with HiResolution (HiRes) psychophysical programming levels. ECAP growth functions were measured for all electrodes along the implant's array in 16 pediatric subjects. Nine of the patients were implanted with a Silastic positioner, whereas seven had no positioner. ECAP thresholds and growth function slopes were calculated. Fifteen of the 16 patients had psychophysical threshold and maximum comfort levels available. Programming levels and ECAP thresholds were compared within and among the subjects. ECAP thresholds showed variability among patients, ranging from 178 to 920 nA at 32 musec pulse width. ECAP thresholds did not depend on electrode position along the cochlea but were lower in the presence of the Silastic positioner (p < 0.001). Thresholds determined with the masker-probe versus the alternating polarity paradigms revealed moderate (r = 0.76) correlation. Growth function slopes also showed considerable variation among patients. Unlike thresholds, slopes decreased from apical to basal cochlear locations (p < 0.001) but showed no difference between the absence and presence of the positioner. Programming levels in HiRes were correlated with ECAP threshold levels. When ECAP thresholds were adjusted for each patient by the difference between M level and ECAP threshold at electrode 9, however, overall correlation between the two measurements was excellent (r = 0.98, N = 224). In pediatric subjects with the Clarion HiFocus electrode, ECAP growth function thresholds appear to decrease with the presence of the Silastic positioner but are unaffected by electrode position along the array. Growth function slope, however, depends on electrode position along the array but not on the presence of the positioner. ECAP programming levels can reliably predict stimulus intensities within the patients' dynamic ranges, but considerable variability is seen between ECAP thresholds and HiRes programming levels.

How Fast? How Far? How Much? What We Need to Learn from the Past Behavior of Ice Sheets, and What They Might Not Tell Us

NASA Astrophysics Data System (ADS)

Alley, R. B.

2016-12-01

Paleoclimatic data support physical understanding that changes in ice sheets are primarily caused by changes in ocean temperature and in melting from above. With interesting qualifications, ice sheets tend to grow as accumulation rate in central regions drops into an ice age, and to shrink as accumulation rate rises. Changes in sea level may be influential but generally are too small and slow to be of primary importance. Thus, future atmospheric warming, oceanic warming and changes in oceanic circulation are especially important to future ice-sheet behavior. Paleoclimatic data support models and physical understanding that sustained warming beyond thresholds will cause progressively larger sea-level rise, up to quite high values, although the thresholds remain poorly quantified. Several indirect lines of evidence indicate great shrinkage or loss of parts or all of the Greenland ice sheet and marine sectors of the Antarctic ice sheet under warmth corresponding to CO2 levels similar to the modern or committed level. Despite this evidence, the state of the ice sheets during the most recent times warmer than today, including MIS 5e, remains unclear. The Greenland ice sheet did survive MIS 5e, but that may reflect warmth sufficient to remove the ice sheet but not sustained long enough to do so; greater warming in the future could cause much faster sea-level rise than generated in the past. Several indirect lines of evidence indicate that the marine basins of the West Antarctic Ice Sheet deglaciated during MIS 5e, and targeted field data could clarify this greatly. Physical understanding suggests, however, that even if this deglaciation did occur, it may have been slower than is possible in an even warmer future world; past rates of sea-level rise may define minimum rather than likely future rates.

Threshold thickness for applying diffusion equation in thin tissue optical imaging

NASA Astrophysics Data System (ADS)

Zhang, Yunyao; Zhu, Jingping; Cui, Weiwen; Nie, Wei; Li, Jie; Xu, Zhenghong

2014-08-01

We investigated the suitability of the semi-infinite model of the diffusion equation when using diffuse optical imaging (DOI) to image thin tissues with double boundaries. Both diffuse approximation and Monte Carlo methods were applied to simulate light propagation in the thin tissue model with variable optical parameters and tissue thicknesses. A threshold value of the tissue thickness was defined as the minimum thickness in which the semi-infinite model exhibits the same reflected intensity as that from the double-boundary model and was generated as the final result. In contrast to our initial hypothesis that all optical properties would affect the threshold thickness, our results show that only absorption coefficient is the dominant parameter and the others are negligible. The threshold thickness decreases from 1 cm to 4 mm as the absorption coefficient grows from 0.01 mm-1 to 0.2 mm-1. A look-up curve was derived to guide the selection of the appropriate model during the optical diagnosis of thin tissue cancers. These results are useful in guiding the development of the endoscopic DOI for esophageal, cervical and colorectal cancers, among others.

Nonlinear threshold behavior during the loss of Arctic sea ice.

PubMed

Eisenman, I; Wettlaufer, J S

2009-01-06

In light of the rapid recent retreat of Arctic sea ice, a number of studies have discussed the possibility of a critical threshold (or "tipping point") beyond which the ice-albedo feedback causes the ice cover to melt away in an irreversible process. The focus has typically been centered on the annual minimum (September) ice cover, which is often seen as particularly susceptible to destabilization by the ice-albedo feedback. Here, we examine the central physical processes associated with the transition from ice-covered to ice-free Arctic Ocean conditions. We show that although the ice-albedo feedback promotes the existence of multiple ice-cover states, the stabilizing thermodynamic effects of sea ice mitigate this when the Arctic Ocean is ice covered during a sufficiently large fraction of the year. These results suggest that critical threshold behavior is unlikely during the approach from current perennial sea-ice conditions to seasonally ice-free conditions. In a further warmed climate, however, we find that a critical threshold associated with the sudden loss of the remaining wintertime-only sea ice cover may be likely.

Nonlinear threshold behavior during the loss of Arctic sea ice

PubMed Central

Eisenman, I.; Wettlaufer, J. S.

2009-01-01

In light of the rapid recent retreat of Arctic sea ice, a number of studies have discussed the possibility of a critical threshold (or “tipping point”) beyond which the ice–albedo feedback causes the ice cover to melt away in an irreversible process. The focus has typically been centered on the annual minimum (September) ice cover, which is often seen as particularly susceptible to destabilization by the ice–albedo feedback. Here, we examine the central physical processes associated with the transition from ice-covered to ice-free Arctic Ocean conditions. We show that although the ice–albedo feedback promotes the existence of multiple ice-cover states, the stabilizing thermodynamic effects of sea ice mitigate this when the Arctic Ocean is ice covered during a sufficiently large fraction of the year. These results suggest that critical threshold behavior is unlikely during the approach from current perennial sea-ice conditions to seasonally ice-free conditions. In a further warmed climate, however, we find that a critical threshold associated with the sudden loss of the remaining wintertime-only sea ice cover may be likely. PMID:19109440

Potential benefits of minimum unit pricing for alcohol versus a ban on below cost selling in England 2014: modelling study.

PubMed

Brennan, Alan; Meng, Yang; Holmes, John; Hill-McManus, Daniel; Meier, Petra S

2014-09-30

To evaluate the potential impact of two alcohol control policies under consideration in England: banning below cost selling of alcohol and minimum unit pricing. Modelling study using the Sheffield Alcohol Policy Model version 2.5. England 2014-15. Adults and young people aged 16 or more, including subgroups of moderate, hazardous, and harmful drinkers. Policy to ban below cost selling, which means that the selling price to consumers could not be lower than tax payable on the product, compared with policies of minimum unit pricing at £0.40 (€0.57; $0.75), 45 p, and 50 p per unit (7.9 g/10 mL) of pure alcohol. Changes in mean consumption in terms of units of alcohol, drinkers' expenditure, and reductions in deaths, illnesses, admissions to hospital, and quality adjusted life years. The proportion of the market affected is a key driver of impact, with just 0.7% of all units estimated to be sold below the duty plus value added tax threshold implied by a ban on below cost selling, compared with 23.2% of units for a 45 p minimum unit price. Below cost selling is estimated to reduce harmful drinkers' mean annual consumption by just 0.08%, around 3 units per year, compared with 3.7% or 137 units per year for a 45 p minimum unit price (an approximately 45 times greater effect). The ban on below cost selling has a small effect on population health-saving an estimated 14 deaths and 500 admissions to hospital per annum. In contrast, a 45 p minimum unit price is estimated to save 624 deaths and 23,700 hospital admissions. Most of the harm reductions (for example, 89% of estimated deaths saved per annum) are estimated to occur in the 5.3% of people who are harmful drinkers. The ban on below cost selling, implemented in the England in May 2014, is estimated to have small effects on consumption and health harm. The previously announced policy of a minimum unit price, if set at expected levels between 40 p and 50 p per unit, is estimated to have an approximately 40-50 times greater effect. © Brennan et al 2014.

Potential benefits of minimum unit pricing for alcohol versus a ban on below cost selling in England 2014: modelling study

PubMed Central

Meng, Yang; Holmes, John; Hill-McManus, Daniel; Meier, Petra S

2014-01-01

Objective To evaluate the potential impact of two alcohol control policies under consideration in England: banning below cost selling of alcohol and minimum unit pricing. Design Modelling study using the Sheffield Alcohol Policy Model version 2.5. Setting England 2014-15. Population Adults and young people aged 16 or more, including subgroups of moderate, hazardous, and harmful drinkers. Interventions Policy to ban below cost selling, which means that the selling price to consumers could not be lower than tax payable on the product, compared with policies of minimum unit pricing at £0.40 (€0.57; $0.75), 45p, and 50p per unit (7.9 g/10 mL) of pure alcohol. Main outcome measures Changes in mean consumption in terms of units of alcohol, drinkers’ expenditure, and reductions in deaths, illnesses, admissions to hospital, and quality adjusted life years. Results The proportion of the market affected is a key driver of impact, with just 0.7% of all units estimated to be sold below the duty plus value added tax threshold implied by a ban on below cost selling, compared with 23.2% of units for a 45p minimum unit price. Below cost selling is estimated to reduce harmful drinkers’ mean annual consumption by just 0.08%, around 3 units per year, compared with 3.7% or 137 units per year for a 45p minimum unit price (an approximately 45 times greater effect). The ban on below cost selling has a small effect on population health—saving an estimated 14 deaths and 500 admissions to hospital per annum. In contrast, a 45p minimum unit price is estimated to save 624 deaths and 23 700 hospital admissions. Most of the harm reductions (for example, 89% of estimated deaths saved per annum) are estimated to occur in the 5.3% of people who are harmful drinkers. Conclusions The ban on below cost selling, implemented in the England in May 2014, is estimated to have small effects on consumption and health harm. The previously announced policy of a minimum unit price, if set at expected levels between 40p and 50p per unit, is estimated to have an approximately 40-50 times greater effect. PMID:25270743

Predicting the performance of local seismic networks using Matlab and Google Earth.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chael, Eric Paul

2009-11-01

We have used Matlab and Google Earth to construct a prototype application for modeling the performance of local seismic networks for monitoring small, contained explosions. Published equations based on refraction experiments provide estimates of peak ground velocities as a function of event distance and charge weight. Matlab routines implement these relations to calculate the amplitudes across a network of stations from sources distributed over a geographic grid. The amplitudes are then compared to ambient noise levels at the stations, and scaled to determine the smallest yield that could be detected at each source location by a specified minimum number ofmore » stations. We use Google Earth as the primary user interface, both for positioning the stations of a hypothetical local network, and for displaying the resulting detection threshold contours.« less

Radio Frequency Compatibility of an RFID Tag on Glideslope Navigation Receivers

NASA Technical Reports Server (NTRS)

Nguyen, Truong X.; Mielnik, John J.

2008-01-01

A process is demonstrated to show compatibility between a radio frequency identification (RFID) tag and an aircraft glideslope (GS) radio receiver. The particular tag chosen was previously shown to have significant peak spurious emission levels that far exceeded the emission limits in the GS aeronautical band. The spurious emissions are emulated in the study by capturing the RFID fundamental transmission and playing back the signal in the GS band. The signal capturing and playback are achieved with a vector signal generator and a spectrum analyzer that can output the in-phase and quadrature components (IQ). The simulated interference signal is combined with a desired GS signal before being injected into a GS receiver s antenna port for interference threshold determination. Minimum desired propagation loss values to avoid interference are then computed and compared against actual propagation losses for several aircraft.

Comparison of software and human observers in reading images of the CDMAM test object to assess digital mammography systems

NASA Astrophysics Data System (ADS)

Young, Kenneth C.; Cook, James J. H.; Oduko, Jennifer M.; Bosmans, Hilde

2006-03-01

European Guidelines for quality control in digital mammography specify minimum and achievable standards of image quality in terms of threshold contrast, based on readings of images of the CDMAM test object by human observers. However this is time-consuming and has large inter-observer error. To overcome these problems a software program (CDCOM) is available to automatically read CDMAM images, but the optimal method of interpreting the output is not defined. This study evaluates methods of determining threshold contrast from the program, and compares these to human readings for a variety of mammography systems. The methods considered are (A) simple thresholding (B) psychometric curve fitting (C) smoothing and interpolation and (D) smoothing and psychometric curve fitting. Each method leads to similar threshold contrasts but with different reproducibility. Method (A) had relatively poor reproducibility with a standard error in threshold contrast of 18.1 +/- 0.7%. This was reduced to 8.4% by using a contrast-detail curve fitting procedure. Method (D) had the best reproducibility with an error of 6.7%, reducing to 5.1% with curve fitting. A panel of 3 human observers had an error of 4.4% reduced to 2.9 % by curve fitting. All automatic methods led to threshold contrasts that were lower than for humans. The ratio of human to program threshold contrasts varied with detail diameter and was 1.50 +/- .04 (sem) at 0.1mm and 1.82 +/- .06 at 0.25mm for method (D). There were good correlations between the threshold contrast determined by humans and the automated methods.

The convective noise floor for the spectroscopic detection of low mass companions to solar type stars

NASA Technical Reports Server (NTRS)

Deming, D.; Espenak, F.; Jennings, D. E.; Brault, J. W.

1986-01-01

The threshold mass for the unambiguous spectroscopic detection of low mass companions to solar type stars is defined here as the time when the maximum acceleration in the stellar radial velocity due to the Doppler reflex of the companion exceeds the apparent acceleration produced by changes in convection. An apparent acceleration of 11 m/s/yr in integrated sunlight was measured using near infrared Fourier transform spectroscopy. This drift in the apparent solar velocity is attributed to a lessening in the magnetic inhibition of granular convection as solar minimum approaches. The threshold mass for spectroscopic detection of companions to a one solar mass star is estimated at below one Jupiter mass.

An improved TV caption image binarization method

NASA Astrophysics Data System (ADS)

Jiang, Mengdi; Cheng, Jianghua; Chen, Minghui; Ku, Xishu

2018-04-01

TV Video caption image binarization has important influence on semantic video retrieval. An improved binarization method for caption image is proposed in this paper. In order to overcome the shortcomings of ghost and broken strokes problems of traditional Niblack method, the method has considered the global information of the images and the local information of the images. First, Tradition Otsu and Niblack thresholds are used for initial binarization. Second, we introduced the difference between maximum and minimum values in the local window as a third threshold to generate two images. Finally, with a logic AND operation of the two images, great results were obtained. The experiment results prove that the proposed method is reliable and effective.

End-pumped continuous-wave intracavity yellow Raman laser at 590 nm with SrWO4 Raman crystal

NASA Astrophysics Data System (ADS)

Yang, F. G.; You, Z. Y.; Zhu, Z. J.; Wang, Y.; Li, J. F.; Tu, C. Y.

2010-01-01

We present an end-pumped continuous-wave intra-cavity yellow Raman laser at 590 nm with a 60 mm long pure crystal SrWO4 and an intra-cavity LiB3O5 frequency doubling crystal. The highest output power of yellow laser at 590 nm was 230 mW and the output power and threshold were found to be correlative with the polarized directions of pure single crystal SrWO4 deeply. Along different directions, the minimum and maximum thresholds of yellow Raman laser at 590 nm were measured to be 2.8 W and 14.3 W with respect to 808 nm LD pump power, respectively.

GAS PHOTOTUBE CIRCUIT

DOEpatents

Richardson, J.H.

1958-03-01

This patent pertains to electronic circuits for measuring the intensity of light and is especially concerned with measurement between preset light thresholds. Such a circuit has application in connection with devices for reading-out information stored on punch cards or tapes where the cards and tapes are translucent. By the novel arrangement of this invention thc sensitivity of a gas phototube is maintained at a low value when the light intensity is below a first threshold level. If the light level rises above the first threshold level, the tube is rendered highly sensitive and an output signal will vary in proportion to the light intensity change. When the light level decreases below a second threshold level, the gas phototube is automatically rendered highly insensitive. Each of these threshold points is adjustable.

MO-DE-207A-12: Toward Patient-Specific 4DCT Reconstruction Using Adaptive Velocity Binning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morris, E.D.; Glide-Hurst, C.; Wayne State University, Detroit, MI

2016-06-15

Purpose: While 4DCT provides organ/tumor motion information, it often samples data over 10–20 breathing cycles. For patients presenting with compromised pulmonary function, breathing patterns can change over the acquisition time, potentially leading to tumor delineation discrepancies. This work introduces a novel adaptive velocity-modulated binning (AVB) 4DCT algorithm that modulates the reconstruction based on the respiratory waveform, yielding a patient-specific 4DCT solution. Methods: AVB was implemented in a research reconstruction configuration. After filtering the respiratory waveform, the algorithm examines neighboring data to a phase reconstruction point and the temporal gate is widened until the difference between the reconstruction point and waveformmore » exceeds a threshold value—defined as percent difference between maximum/minimum waveform amplitude. The algorithm only impacts reconstruction if the gate width exceeds a set minimum temporal width required for accurate reconstruction. A sensitivity experiment of threshold values (0.5, 1, 5, 10, and 12%) was conducted to examine the interplay between threshold, signal to noise ratio (SNR), and image sharpness for phantom and several patient 4DCT cases using ten-phase reconstructions. Individual phase reconstructions were examined. Subtraction images and regions of interest were compared to quantify changes in SNR. Results: AVB increased signal in reconstructed 4DCT slices for respiratory waveforms that met the prescribed criteria. For the end-exhale phases, where the respiratory velocity is low, patient data revealed a threshold of 0.5% demonstrated increased SNR in the AVB reconstructions. For intermediate breathing phases, threshold values were required to be >10% to notice appreciable changes in CT intensity with AVB. AVB reconstructions exhibited appreciably higher SNR and reduced noise in regions of interest that were photon deprived such as the liver. Conclusion: We demonstrated that patient-specific velocity-based 4DCT reconstruction is feasible. Image noise was reduced with AVB, suggesting potential applications for low-dose acquisitions and to improve 4DCT reconstruction for irregular breathing patients. The submitting institution holds research agreements with Philips Healthcare.« less

Influence of fatiguing noise on auditory evoked responses to stimuli of various levels in a beluga whale, Delphinapterus leucas.

PubMed

Popov, Vladimir V; Sysueva, Evgeniya V; Nechaev, Dmitry I; Rozhnov, Viatcheslav V; Supin, Alexander Ya

2017-03-15

The negative impact of man-made noise on the hearing of odontocetes has attracted considerable recent attention. In the majority of studies, permanent or temporary reductions in sensitivity, known as permanent or temporary threshold shift (PTS or TTS, respectively), have been investigated. In the present study, the effects of a fatiguing sound on the hearing of a beluga whale, Delphinapterus leucas , within a wide range of levels of test signals was investigated. The fatiguing noise was half-octave band-limited noise centered at 32 kHz. Post-exposure effects of this noise on the evoked responses to test stimuli (rhythmic pip trains with a 45-kHz center frequency) at various levels (from threshold to 60 dB above threshold) were measured. For baseline (pre-exposure) responses, the magnitude-versus-level function featured a segment of steep magnitude dependence on level (up to 30 dB above threshold) that was followed by a plateau segment that featured little dependence on level (30 to 55 dB above threshold). Post-exposure, the function shifted upward along the level scale. The shift was 23 dB at the threshold and up to 33 dB at the supra-threshold level. Owing to the plateau in the magnitude-versus-level function, post-exposure suppression of responses depended on the stimulus level such that higher levels corresponded to less suppression. The experimental data may be modeled based on the compressive non-linearity of the cochlea. According to the model, post-exposure responses of the cochlea to high-level stimuli are minimally suppressed compared with the pre-exposure responses, despite a substantially increased threshold. © 2017. Published by The Company of Biologists Ltd.

40 CFR Table Jj-1 to Subpart Jj of... - Animal Population Threshold Level Below Which Facilities Are Not Required To Report Emissions...

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Animal Population Threshold Level... Subpart JJ of Part 98—Animal Population Threshold Level Below Which Facilities Are Not Required To Report...,200 Swine 34,100 Poultry: Layers 723,600 Broilers 38,160,000 Turkeys 7,710,000 1 The threshold head...

Threshold dose for discrimination of nicotine via cigarette smoking.

PubMed

Perkins, Kenneth A; Kunkle, Nicole; Karelitz, Joshua L; Michael, Valerie C; Donny, Eric C

2016-06-01

The lowest nicotine threshold "dose" in cigarettes discriminated from a cigarette containing virtually no nicotine may help inform the minimum dose maintaining dependence. Spectrum research cigarettes (from NIDA) differing in nicotine content were used to evaluate a procedure to determine discrimination thresholds. Dependent smokers (n = 18; 13 M, 5 F) were tested on ability to discriminate cigarettes with nicotine contents of 11, 5, 2.4, and 1.3 mg/g, one per session, from the "ultralow" cigarette with 0.4 mg/g, after having discriminated 16 mg/g from 0.4 mg/g (all had 9-10 mg "tar"). Exposure to each was limited to 4 puffs/trial. All subjects were abstinent from smoking overnight prior to each session, and the number of sessions was determined by the participant's success in discrimination behavior on >80 % of trials. Subjective perceptions and behavioral choice between cigarettes were also assessed and related to discrimination behavior. The median threshold was 11 mg/g, but the range was 2.4 to 16 mg/g, suggesting wide variability in discrimination threshold. Compared to the ultralow, puff choice was greater for the subject's threshold dose but only marginal for the subthreshold (next lowest nicotine) cigarette. Threshold and subthreshold also differed on subjective perceptions but not withdrawal relief. Under these testing conditions, threshold content for discriminating nicotine via cigarettes may be 11 mg/g or greater for most smokers, but some can discriminate nicotine contents one-half or one-quarter this amount. Further study with other procedures and cigarette exposure amounts may identify systematic differences in nicotine discrimination thresholds.

On the optimal z-score threshold for SISCOM analysis to localize the ictal onset zone.

PubMed

De Coster, Liesbeth; Van Laere, Koen; Cleeren, Evy; Baete, Kristof; Dupont, Patrick; Van Paesschen, Wim; Goffin, Karolien E

2018-04-17

In epilepsy patients, SISCOM or subtraction ictal single photon emission computed tomography co-registered to magnetic resonance imaging has become a routinely used, non-invasive technique to localize the ictal onset zone (IOZ). Thresholding of clusters with a predefined number of standard deviations from normality (z-score) is generally accepted to localize the IOZ. In this study, we aimed to assess the robustness of this parameter in a group of patients with well-characterized drug-resistant epilepsy in whom the exact location of the IOZ was known after successful epilepsy surgery. Eighty patients underwent preoperative SISCOM and were seizure free in a postoperative period of minimum 1 year. SISCOMs with z-threshold 2 and 1.5 were analyzed by two experienced readers separately, blinded from the clinical ground truth data. Their reported location of the IOZ was compared with the operative resection zone. Furthermore, confidence scores of the SISCOM IOZ were compared for the two thresholds. Visual reporting with a z-score threshold of 1.5 and 2 showed no statistically significant difference in localizing correspondence with the ground truth (70 vs. 72% respectively, p = 0.17). Interrater agreement was moderate (κ = 0.65) at the threshold of 1.5, but high (κ = 0.84) at a threshold of 2, where also reviewers were significantly more confident (p < 0.01). SISCOM is a clinically useful, routinely used modality in the preoperative work-up in many epilepsy surgery centers. We found no significant differences in localizing value of the IOZ using a threshold of 1.5 or 2, but interrater agreement and reader confidence were higher using a z-score threshold of 2.

75 FR 22884 - Self-Regulatory Organizations; NYSE Arca, Inc.; Notice of Filing and Immediate Effectiveness of...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-30

... uniform time frame for the introduction of new LEAPS on equity option classes, options on exchange traded... minimum volume threshold per underlying class to qualify for the introduction of a new expiration year of... 30 days from the date on which it was filed, or such shorter time as the Commission may designate if...

Principles of Air Defense and Air Vehicle Penetration

DTIC Science & Technology

2000-03-01

Range For reliable dateetien, the target signal must reach some minimum or threshold value called S . . When internal noise is the only interfer...analyze air defense and air vehicle penetration. Unique expected value models are developed with frequent numerical examples. Radar...penetrator in the presence of spurious returns from internal and external noise will be discussed. Tracking With sufficient sensor information to determine

What Are the Advantages Today of Having an Upper Secondary Qualification? Education Indicators in Focus. No. 34

ERIC Educational Resources Information Center

OECD Publishing, 2015

2015-01-01

In most OECD countries, the large majority of adults had at least an upper secondary qualification in 2013, making the completion of upper secondary education the minimum threshold for successful labour market entry and continued employability or the pursuit of further education. Young people who left school before completing upper secondary…

Qualification of an Acceptable Alternative to Halon 1211 DOD Flightline Extinguishers

DTIC Science & Technology

2008-09-01

Minimum Performance Standard MSDS Material Safety Data Sheet NATO North Atlantic Treaty Organization NAWCAD Naval Air Warfare Center Aircraft...included chronic and acute occupational exposure limits and cardiotoxicity. Alternatives that were carcinogens or that had any adverse developmental...gear to fight the fires Does not exceed pain threshold for exposed skin Each unit tested met this performance objective 2. Firefighting

49 CFR 38.25 - Doors, steps and thresholds.

Code of Federal Regulations, 2011 CFR

2011-10-01

... lift platforms shall have a band of color(s) running the full width of the step or edge which contrasts from the step tread and riser, or lift or ramp surface, either light-on-dark or dark-on-light. (c) Door... opening and the raised lift platform, or highest point of a ramp, shall be a minimum of 68 inches. For...

49 CFR 38.25 - Doors, steps and thresholds.

Code of Federal Regulations, 2010 CFR

2010-10-01

... lift platforms shall have a band of color(s) running the full width of the step or edge which contrasts from the step tread and riser, or lift or ramp surface, either light-on-dark or dark-on-light. (c) Door... opening and the raised lift platform, or highest point of a ramp, shall be a minimum of 68 inches. For...

78 FR 11795 - Minimum Technical Standards for Class II Gaming Systems and Equipment

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-20

... threshold amount. The Commission increased that amount in the MICS from $1,000,000 to $3,000,000. The... considered to be small entities for the purposes of the Regulatory Flexibility Act. Small Business Regulatory Enforcement Fairness Act The proposed rule is not a major rule under 5 U.S.C. 804(2), the Small Business...

Optimal electrode selection for multi-channel electroencephalogram based detection of auditory steady-state responses.

PubMed

Van Dun, Bram; Wouters, Jan; Moonen, Marc

2009-07-01

Auditory steady-state responses (ASSRs) are used for hearing threshold estimation at audiometric frequencies. Hearing impaired newborns, in particular, benefit from this technique as it allows for a more precise diagnosis than traditional techniques, and a hearing aid can be better fitted at an early age. However, measurement duration of current single-channel techniques is still too long for clinical widespread use. This paper evaluates the practical performance of a multi-channel electroencephalogram (EEG) processing strategy based on a detection theory approach. A minimum electrode set is determined for ASSRs with frequencies between 80 and 110 Hz using eight-channel EEG measurements of ten normal-hearing adults. This set provides a near-optimal hearing threshold estimate for all subjects and improves response detection significantly for EEG data with numerous artifacts. Multi-channel processing does not significantly improve response detection for EEG data with few artifacts. In this case, best response detection is obtained when noise-weighted averaging is applied on single-channel data. The same test setup (eight channels, ten normal-hearing subjects) is also used to determine a minimum electrode setup for 10-Hz ASSRs. This configuration allows to record near-optimal signal-to-noise ratios for 80% of subjects.

Laser ignition of liquid petroleum gas at elevated pressures

NASA Astrophysics Data System (ADS)

Loktionov, E.; Pasechnikov, N.; Telekh, V.

2017-11-01

Recent development of laser spark plugs for internal combustion engines have shown lack of data on laser ignition of fuel mixtures at multi-bar pressures needed for laser pulse energy and focusing optimisation. Methane and hydrogen based mixtures are comparatively well investigated, but propane and butane based ones (LPG), which are widely used in vehicles, are still almost unstudied. Optical breakdown thresholds in gases decrease with pressure increase up to ca. 100 bar, but breakdown is not a sufficient condition for combustion ignition. So minimum ignition energy (MIE) becomes more important for combustion core onset, and its dependency on mixture composition and pressure has several important features. For example, unlike breakdown threshold, is poorly dependent on laser pulse length, at least in pico- and to microsecond range. We have defined experimentally the dependencies of minimum picosecond laser pulse energies (MIE related value) needed for ignition of LPG based mixtures of 1.0 to 1.6 equivalence ratios and pressure of 1.0 to 3.5 bar. In addition to expected values decrease, low-energy flammability range broadening has been found at pressure increase. Laser ignition of LPG in Wankel rotary engine is reported for the first time.

Formation of organic layer on femtosecond laser-induced periodic surface structures

NASA Astrophysics Data System (ADS)

Yasumaru, Naoki; Sentoku, Eisuke; Kiuchi, Junsuke

2017-05-01

Two types of laser-induced periodic surface structures (LIPSS) formed on titanium by femtosecond (fs) laser pulses (λ = 800 nm, τ = 180 fs, ν = 1 kHz) in air were investigated experimentally. At a laser fluence F above the ablation threshold, LIPSS with a minimum mean spacing of D < λ⁄2 were observed perpendicular to the laser polarization direction. In contrast, for F slightly below than the ablation threshold, ultrafine LIPSS with a minimum value of D < λ/10 were formed parallel to the polarization direction. The surface roughness of the parallel-oriented LIPSS was almost the same as that of the non-irradiated surface, unlike the high roughness of the perpendicular-oriented LIPSS. In addition, although the surface state of the parallel-oriented LIPSS was the same as that of the non-irradiated surface, the perpendicular-oriented LIPSS were covered with an organic thin film similar to a cellulose derivative that cannot be easily formed by conventional chemical synthesis. The results of these surface analyses indicate that these two types of LIPSS are formed through different mechanisms. This fs-laser processing technique may become a new technology for the artificial synthesis of cellulose derivatives.

Long-Term Impairment of Sound Processing in the Auditory Midbrain by Daily Short-Term Exposure to Moderate Noise.

PubMed

Cheng, Liang; Wang, Shao-Hui; Peng, Kang; Liao, Xiao-Mei

2017-01-01

Most citizen people are exposed daily to environmental noise at moderate levels with a short duration. The aim of the present study was to determine the effects of daily short-term exposure to moderate noise on sound level processing in the auditory midbrain. Sound processing properties of auditory midbrain neurons were recorded in anesthetized mice exposed to moderate noise (80 dB SPL, 2 h/d for 6 weeks) and were compared with those from age-matched controls. Neurons in exposed mice had a higher minimum threshold and maximum response intensity, a longer first spike latency, and a higher slope and narrower dynamic range for rate level function. However, these observed changes were greater in neurons with the best frequency within the noise exposure frequency range compared with those outside the frequency range. These sound processing properties also remained abnormal after a 12-week period of recovery in a quiet laboratory environment after completion of noise exposure. In conclusion, even daily short-term exposure to moderate noise can cause long-term impairment of sound level processing in a frequency-specific manner in auditory midbrain neurons.

Long-Term Impairment of Sound Processing in the Auditory Midbrain by Daily Short-Term Exposure to Moderate Noise

PubMed Central

Cheng, Liang; Wang, Shao-Hui; Peng, Kang

2017-01-01

Most citizen people are exposed daily to environmental noise at moderate levels with a short duration. The aim of the present study was to determine the effects of daily short-term exposure to moderate noise on sound level processing in the auditory midbrain. Sound processing properties of auditory midbrain neurons were recorded in anesthetized mice exposed to moderate noise (80 dB SPL, 2 h/d for 6 weeks) and were compared with those from age-matched controls. Neurons in exposed mice had a higher minimum threshold and maximum response intensity, a longer first spike latency, and a higher slope and narrower dynamic range for rate level function. However, these observed changes were greater in neurons with the best frequency within the noise exposure frequency range compared with those outside the frequency range. These sound processing properties also remained abnormal after a 12-week period of recovery in a quiet laboratory environment after completion of noise exposure. In conclusion, even daily short-term exposure to moderate noise can cause long-term impairment of sound level processing in a frequency-specific manner in auditory midbrain neurons. PMID:28589040

A Minimum Delta V Orbit Maintenance Strategy for Low-Altitude Missions Using Burn Parameter Optimization

NASA Technical Reports Server (NTRS)

Brown, Aaron J.

2011-01-01

Orbit maintenance is the series of burns performed during a mission to ensure the orbit satisfies mission constraints. Low-altitude missions often require non-trivial orbit maintenance Delta V due to sizable orbital perturbations and minimum altitude thresholds. A strategy is presented for minimizing this Delta V using impulsive burn parameter optimization. An initial estimate for the burn parameters is generated by considering a feasible solution to the orbit maintenance problem. An low-lunar orbit example demonstrates the Delta V savings from the feasible solution to the optimal solution. The strategy s extensibility to more complex missions is discussed, as well as the limitations of its use.

Minimum Requirements for Taxicab Security Cameras*

PubMed Central

Zeng, Shengke; Amandus, Harlan E.; Amendola, Alfred A.; Newbraugh, Bradley H.; Cantis, Douglas M.; Weaver, Darlene

2015-01-01

Problem The homicide rate of taxicab-industry is 20 times greater than that of all workers. A NIOSH study showed that cities with taxicab-security cameras experienced significant reduction in taxicab driver homicides. Methods Minimum technical requirements and a standard test protocol for taxicab-security cameras for effective taxicab-facial identification were determined. The study took more than 10,000 photographs of human-face charts in a simulated-taxicab with various photographic resolutions, dynamic ranges, lens-distortions, and motion-blurs in various light and cab-seat conditions. Thirteen volunteer photograph-evaluators evaluated these face photographs and voted for the minimum technical requirements for taxicab-security cameras. Results Five worst-case scenario photographic image quality thresholds were suggested: the resolution of XGA-format, highlight-dynamic-range of 1 EV, twilight-dynamic-range of 3.3 EV, lens-distortion of 30%, and shutter-speed of 1/30 second. Practical Applications These minimum requirements will help taxicab regulators and fleets to identify effective taxicab-security cameras, and help taxicab-security camera manufacturers to improve the camera facial identification capability. PMID:26823992

Methods for automatic trigger threshold adjustment

DOEpatents

Welch, Benjamin J; Partridge, Michael E

2014-03-18

Methods are presented for adjusting trigger threshold values to compensate for drift in the quiescent level of a signal monitored for initiating a data recording event, thereby avoiding false triggering conditions. Initial threshold values are periodically adjusted by re-measuring the quiescent signal level, and adjusting the threshold values by an offset computation based upon the measured quiescent signal level drift. Re-computation of the trigger threshold values can be implemented on time based or counter based criteria. Additionally, a qualification width counter can be utilized to implement a requirement that a trigger threshold criterion be met a given number of times prior to initiating a data recording event, further reducing the possibility of a false triggering situation.

Geographical diffusion of prazosin across Veterans Health Administration: Examination of regional variation in daily dosing and quality indicators among veterans with posttraumatic stress disorder.

PubMed

Abrams, Thad E; Lund, Brian C; Alexander, Bruce; Bernardy, Nancy C; Friedman, Matthew J

2015-01-01

Posttraumatic stress disorder (PTSD) is a high-priority treatment area for the Veterans Health Administration (VHA), and dissemination patterns of innovative, efficacious therapies can inform areas for potential improvement of diffusion efforts and quality prescribing. In this study, we replicated a prior examination of the period prevalence of prazosin use as a function of distance from Puget Sound, Washington, where prazosin was first tested as an effective treatment for PTSD and where prazosin use was previously shown to be much greater than in other parts of the United States. We tested the following three hypotheses related to prazosin geographic diffusion: (1) a positive geographical correlation exists between the distance from Puget Sound and the proportion of users treated according to a guideline recommended minimum therapeutic target dose (>/=6 mg/d), (2) an inverse geographic correlation exists between prazosin and benzodiazepine use, and (3) no geographical correlation exists between prazosin use and serotonin reuptake inhibitor/serotonin norepinephrine reuptake inhibitor (SSRI/SNRI) use. Among a national sample of veterans with PTSD, overall prazosin utilization increased from 5.5 to 14.8% from 2006 to 2012. During this time period, rates at the Puget Sound VHA location declined from 34.4 to 29.9%, whereas utilization rates at locations a minimum of 2,500 miles away increased from 3.0 to 12.8%. Rates of minimum target dosing fell from 42.6 to 34.6% at the Puget Sound location. In contrast, at distances of at least 2,500 miles from Puget Sound, minimum threshold dosing rates remained stable (range, 18.6 to 17.7%). No discernible association was demonstrated between SSRI/SNRI or benzodiazepine utilization and the geographic distance from Puget Sound. Minimal threshold dosing of prazosin correlated positively with increased diffusion of prazosin use, but there was still a distance diffusion gradient. Although prazosin adoption has improved, geographic differences persist in both prescribing rates and minimum target dosing. Importantly, these regional disparities appear to be limited to prazosin prescribing and are not meaningfully correlated with SSRI/SNRI and benzodiazepine use as indicators of PTSD prescribing quality.

The trigger system of the JEM-EUSO Project

NASA Astrophysics Data System (ADS)

Bertaina, M.; Ebisuzaki, T.; Hamada, T.; Ikeda, H.; Kawasai, Y.; Sawabe, T.; Takahashi, Y.; JEM-EUSO Collaboration

The trigger system of JEM-EUSO should face different major challenging points: a) cope with the limited down-link transmission rate from the ISS to Earth, by operating a severe on-board and on-time data reduction; b) use very fast, low power consuming and radiation hard electronics; c) have a high signal-over-noise performance and flexibility in order to lower as much as possible the energy threshold of the detector, adjust the system to a variable nightglow background, and trigger on different categories of events (images insisting on the same pixels or crossing huge portions of the entire focal surface). Based on the above stringent requirements, the main ingredients for the trigger logic are: the Gate Time Unit (GTU); the minimum number Nthresh of photo-electrons piling up in a GTU in a pixel to be fired; the persistency level Npers, in which fired pixels are over threshold; the localization and correlation in space and time of the fired pixels, that distinguish a real EAS from an accidental background enhancement. The core of the trigger logic is the Track Trigger Algorithm that has been specifically developed for this purpose. Its characteristics, preliminary performance and its possible implementation on FPGA or DSP will be discussed together with a general overview of the architecture of the triggering system of JEM-EUSO.

Heat waves in Senegal : detection, characterization and associated processes.

NASA Astrophysics Data System (ADS)

Gnacoussa Sambou, Marie Jeanne; Janicot, Serge; Badiane, Daouda; Pohl, Benjamin; Dieng, Abdou L.; Gaye, Amadou T.

2017-04-01

Atmospheric configuration and synoptic evolution of patterns associated with Senegalese heat wave (HW) are examined on the period 1979-2014 using the Global Surface Summary of the Day (GSOD) observational database and ERA-Interim reanalysis. Since there is no objective and uniform definition of HW events, threshold methods based on atmospheric variables as daily maximum (Tmax) / minimum (Tmin) temperatures and daily mean apparent temperature (AT) are used to define HW threshold detection. Each criterion is related to a specific category of HW events: Tmax (warm day events), Tmin (warm night events) and AT (combining temperature and moisture). These definitions are used in order to characterize as well as possible the warm events over the Senegalese regions (oceanic versus continental region). Statistics on time evolution and spatial distribution of warm events are carried out over the 2 seasons of maximum temperature (March-May and October-November). For each season, a composite of HW events, as well as the most extended event over Senegal (as a case study) are analyzed using usual atmospheric fields (sea level pressure, geopotential height, total column water content, wind components, 2m temperature). This study is part of the project ACASIS (https://acasis.locean-ipsl.upmc.fr/doku.php) on heat waves occurrences over the Sahel and their impact on health. Keywords: heat wave, Senegal, ACASIS.

The impact of cochlear fine structure on hearing thresholds and DPOAE levels

NASA Astrophysics Data System (ADS)

Lee, Jungmee; Long, Glenis; Talmadge, Carrick L.

2004-05-01

Although otoacoustic emissions (OAE) are used as clinical and research tools, the correlation between OAE behavioral estimates of hearing status is not large. In normal-hearing individuals, the level of OAEs can vary as much as 30 dB when the frequency is changed less than 5%. These pseudoperiodic variations of OAE level with frequency are known as fine structure. Hearing thresholds measured with high-frequency resolution reveals a similar (up to 15 dB) fine structure. We examine the impact of OAE and threshold fine structures on the prediction of auditory thresholds from OAE levels. Distortion product otoacoustic emissions (DPOAEs) were measured with sweeping primary tones. Psychoacoustic detection thresholds were measured using pure tones, sweep tones, FM tones, and narrow-band noise. Sweep DPOAE and narrow-band threshold estimates provide estimates that are less influenced by cochlear fine structure and should lead to a higher correlation between OAE levels and psychoacoustic thresholds. [Research supported by PSC CUNY, NIDCD, National Institute on Disability and Rehabilitation Research in U.S. Department of Education, and The Ministry of Education in Korea.

Setting Priorities in Global Child Health Research Investments: Addressing Values of Stakeholders

PubMed Central

Kapiriri, Lydia; Tomlinson, Mark; Gibson, Jennifer; Chopra, Mickey; El Arifeen, Shams; Black, Robert E.; Rudan, Igor

2007-01-01

Aim To identify main groups of stakeholders in the process of health research priority setting and propose strategies for addressing their systems of values. Methods In three separate exercises that took place between March and June 2006 we interviewed three different groups of stakeholders: 1) members of the global research priority setting network; 2) a diverse group of national-level stakeholders from South Africa; and 3) participants at the conference related to international child health held in Washington, DC, USA. Each of the groups was administered different version of the questionnaire in which they were asked to set weights to criteria (and also minimum required thresholds, where applicable) that were a priori defined as relevant to health research priority setting by the consultants of the Child Health and Nutrition Research initiative (CHNRI). Results At the global level, the wide and diverse group of respondents placed the greatest importance (weight) to the criterion of maximum potential for disease burden reduction, while the most stringent threshold was placed on the criterion of answerability in an ethical way. Among the stakeholders’ representatives attending the international conference, the criterion of deliverability, answerability, and sustainability of health research results was proposed as the most important one. At the national level in South Africa, the greatest weight was placed on the criterion addressing the predicted impact on equity of the proposed health research. Conclusions Involving a large group of stakeholders when setting priorities in health research investments is important because the criteria of relevance to scientists and technical experts, whose knowledge and technical expertise is usually central to the process, may not be appropriate to specific contexts and in accordance with the views and values of those who invest in health research, those who benefit from it, or wider society as a whole. PMID:17948948

Large signal-to-noise ratio quantification in MLE for ARARMAX models

NASA Astrophysics Data System (ADS)

Zou, Yiqun; Tang, Xiafei

2014-06-01

It has been shown that closed-loop linear system identification by indirect method can be generally transferred to open-loop ARARMAX (AutoRegressive AutoRegressive Moving Average with eXogenous input) estimation. For such models, the gradient-related optimisation with large enough signal-to-noise ratio (SNR) can avoid the potential local convergence in maximum likelihood estimation. To ease the application of this condition, the threshold SNR needs to be quantified. In this paper, we build the amplitude coefficient which is an equivalence to the SNR and prove the finiteness of the threshold amplitude coefficient within the stability region. The quantification of threshold is achieved by the minimisation of an elaborately designed multi-variable cost function which unifies all the restrictions on the amplitude coefficient. The corresponding algorithm based on two sets of physically realisable system input-output data details the minimisation and also points out how to use the gradient-related method to estimate ARARMAX parameters when local minimum is present as the SNR is small. Then, the algorithm is tested on a theoretical AutoRegressive Moving Average with eXogenous input model for the derivation of the threshold and a gas turbine engine real system for model identification, respectively. Finally, the graphical validation of threshold on a two-dimensional plot is discussed.

Visible lesion thresholds and model predictions for Q-switched 1318-nm and 1540-nm laser exposures to porcine skin

NASA Astrophysics Data System (ADS)

Zohner, Justin J.; Schuster, Kurt J.; Chavey, Lucas J.; Stolarski, David J.; Kumru, Semih S.; Rockwell, Benjamin A.; Thomas, Robert J.; Cain, Clarence P.

2006-02-01

Skin damage thresholds were measured and compared with theoretical predictions using a skin thermal model for near-IR laser pulses at 1318 nm and 1540 nm. For the 1318-nm data, a Q-switched, 50-ns pulse with a spot size of 5 mm was applied to porcine skin and the damage thresholds were determined at 1 hour and 24 hours postexposure using Probit analysis. The same analysis was conducted for a Q-switched, 30-ns pulse at 1540 nm with a spot size of 5 mm. The Yucatan mini-pig was used as the skin model for human skin due to its similarity to pigmented human skin. The ED 50 for these skin exposures at 24 hours postexposure was 10.5 J/cm2 for the 1318-nm exposures, and 6.1 J/cm2 for the 1540-nm exposures. These results were compared to thermal model predictions. We show that the thermal model fails to account for the ED 50 values observed. A brief discussion of the possible causes of this discrepancy is presented. These thresholds are also compared with previously published skin minimum visible lesion (MVL) thresholds and with the ANSI Standard's MPE for 1318-nm lasers at 50 ns and 1540-nm lasers at 30 ns.

Injury thresholds for topical-cream-coated skin of hairless guinea pigs (cavia porcellus) in the near-infrared region

NASA Astrophysics Data System (ADS)

Pocock, Ginger M.; Zohner, Justin J.; Stolarski, David J.; Buchanan, Kelvin C.; Jindra, Nichole M.; Figueroa, Manuel A.; Chavey, Lucas J.; Imholte, Michelle L.; Thomas, Robert J.; Rockwell, Benjamin A.

2006-02-01

The reflectance and absorption of the skin plays a vital role in determining how much radiation will be absorbed by human tissue. Any substance covering the skin would change the way radiation is reflected and absorbed and thus the extent of thermal injury. Hairless guinea pigs (cavia porcellus) in vivo were used to evaluate how the minimum visible lesion threshold for single-pulse laser exposure is changed with a topical agent applied to the skin. The ED 50 for visible lesions due to an Er: glass laser at 1540-nm with a pulse width of 50-ns was determined, and the results were compared with model predictions using a skin thermal model. The ED50 is compared with the damage threshold of skin coated with a highly absorbing topical cream at 1540 nm to determine its effect on damage pathology and threshold. The ED 50 for the guinea pig was then compared to similar studies using Yucatan minipigs and Yorkshire pigs at 1540-nm and nanosecond pulse duration. 1,2 The damage threshold at 24-hours of a Yorkshire pig for a 2.5-3.5-mm diameter beam for 100 ns was 3.2 Jcm -2; very similar to our ED 50 of 3.00 Jcm -2 for the hairless guinea pigs.

The absolute threshold of cone vision

PubMed Central

Koeing, Darran; Hofer, Heidi

2013-01-01

We report measurements of the absolute threshold of cone vision, which has been previously underestimated due to sub-optimal conditions or overly strict subjective response criteria. We avoided these limitations by using optimized stimuli and experimental conditions while having subjects respond within a rating scale framework. Small (1′ fwhm), brief (34 msec), monochromatic (550 nm) stimuli were foveally presented at multiple intensities in dark-adapted retina for 5 subjects. For comparison, 4 subjects underwent similar testing with rod-optimized stimuli. Cone absolute threshold, that is, the minimum light energy for which subjects were just able to detect a visual stimulus with any response criterion, was 203 ± 38 photons at the cornea, ∼0.47 log units lower than previously reported. Two-alternative forced-choice measurements in a subset of subjects yielded consistent results. Cone thresholds were less responsive to criterion changes than rod thresholds, suggesting a limit to the stimulus information recoverable from the cone mosaic in addition to the limit imposed by Poisson noise. Results were consistent with expectations for detection in the face of stimulus uncertainty. We discuss implications of these findings for modeling the first stages of human cone vision and interpreting psychophysical data acquired with adaptive optics at the spatial scale of the receptor mosaic. PMID:21270115

Fish Ecology and Evolution in the World's Oxygen Minimum Zones and Implications of Ocean Deoxygenation.

PubMed

Gallo, N D; Levin, L A

Oxygen minimum zones (OMZs) and oxygen limited zones (OLZs) are important oceanographic features in the Pacific, Atlantic, and Indian Ocean, and are characterized by hypoxic conditions that are physiologically challenging for demersal fish. Thickness, depth of the upper boundary, minimum oxygen levels, local temperatures, and diurnal, seasonal, and interannual oxycline variability differ regionally, with the thickest and shallowest OMZs occurring in the subtropics and tropics. Although most fish are not hypoxia-tolerant, at least 77 demersal fish species from 16 orders have evolved physiological, behavioural, and morphological adaptations that allow them to live under the severely hypoxic, hypercapnic, and at times sulphidic conditions found in OMZs. Tolerance to OMZ conditions has evolved multiple times in multiple groups with no single fish family or genus exploiting all OMZs globally. Severely hypoxic conditions in OMZs lead to decreased demersal fish diversity, but fish density trends are variable and dependent on region-specific thresholds. Some OMZ-adapted fish species are more hypoxia-tolerant than most megafaunal invertebrates and are present even when most invertebrates are excluded. Expansions and contractions of OMZs in the past have affected fish evolution and diversity. Current patterns of ocean warming are leading to ocean deoxygenation, causing the expansion and shoaling of OMZs, which is expected to decrease demersal fish diversity and alter trophic pathways on affected margins. Habitat compression is expected for hypoxia-intolerant species, causing increased susceptibility to overfishing for fisheries species. Demersal fisheries are likely to be negatively impacted overall by the expansion of OMZs in a warming world. © 2016 Elsevier Ltd. All rights reserved.

Development of the Spanish Healthy Food Reference Budget for an adequate social participation at the minimum.

PubMed

Carrillo Álvarez, Elena; Cussó-Parcerisas, Irene; Riera-Romaní, Jordi

2016-12-01

It has been observed that diet quality and food choices vary depending on socio-economic status (SES), especially when measured through income and educational level. Although the reasons behind these differences are multiple, diet cost is a critical determinant in those groups that spend a higher proportion of their budget on food. Reference budgets are priced baskets containing the minimum goods and services necessary for well-described types of families to have an adequate social participation. In the current paper we describe the development and content of the Spanish Healthy Food Basket (SHFB). National dietary guidelines were translated into monthly food baskets. Next, these baskets were validated in terms of acceptability and feasibility through focus group discussions, and finally they were priced. The focus group discussions and the pricing were performed in Barcelona, Spain. Twenty adults aged 30-50 years from different SES backgrounds and their children aged 2-22 years participated in three discussion groups. The SHFB complies with the dietary recommendations for the Spanish population. The monthly cost of this basket ranges from 131·63 € to 573·80 € depending on the type of family. The SHFB does not have the purpose of prescribing what people should eat, but of estimating a minimum budget threshold below which healthy eating is not possible for well-described types of families. Thus, the SHFB is an educative guide on how to plan a healthy food budget and orient policies designed to guarantee food access and reduce SES inequalities.

Estimating Allee dynamics before they can be observed: polar bears as a case study.

PubMed

Molnár, Péter K; Lewis, Mark A; Derocher, Andrew E

2014-01-01

Allee effects are an important component in the population dynamics of numerous species. Accounting for these Allee effects in population viability analyses generally requires estimates of low-density population growth rates, but such data are unavailable for most species and particularly difficult to obtain for large mammals. Here, we present a mechanistic modeling framework that allows estimating the expected low-density growth rates under a mate-finding Allee effect before the Allee effect occurs or can be observed. The approach relies on representing the mechanisms causing the Allee effect in a process-based model, which can be parameterized and validated from data on the mechanisms rather than data on population growth. We illustrate the approach using polar bears (Ursus maritimus), and estimate their expected low-density growth by linking a mating dynamics model to a matrix projection model. The Allee threshold, defined as the population density below which growth becomes negative, is shown to depend on age-structure, sex ratio, and the life history parameters determining reproduction and survival. The Allee threshold is thus both density- and frequency-dependent. Sensitivity analyses of the Allee threshold show that different combinations of the parameters determining reproduction and survival can lead to differing Allee thresholds, even if these differing combinations imply the same stable-stage population growth rate. The approach further shows how mate-limitation can induce long transient dynamics, even in populations that eventually grow to carrying capacity. Applying the models to the overharvested low-density polar bear population of Viscount Melville Sound, Canada, shows that a mate-finding Allee effect is a plausible mechanism for slow recovery of this population. Our approach is generalizable to any mating system and life cycle, and could aid proactive management and conservation strategies, for example, by providing a priori estimates of minimum conservation targets for rare species or minimum eradication targets for pests and invasive species.

Do school classrooms meet the visual requirements of children and recommended vision standards?

PubMed

Negiloni, Kalpa; Ramani, Krishna Kumar; Sudhir, Rachapalle Reddi

2017-01-01

Visual demands of school children tend to vary with diverse classroom environments. The study aimed to evaluate the distance and near Visual Acuity (VA) demand in Indian school classrooms and their comparison with the recommended vision standards. The distance and near VA demands were assessed in 33 classrooms (grades 4 to 12) of eight schools. The VA threshold demand relied on the smallest size of distance and near visual task material and viewing distance. The logMAR equivalents of minimum VA demand at specific seating positions (desk) and among different grades were evaluated. The near threshold was converted into actual near VA demand by including the acuity reserve. The existing dimensions of chalkboard and classroom, gross area in a classroom per student and class size in all the measured classrooms were compared to the government recommended standards. In 33 classrooms assessed (35±10 students per room), the average distance and near logMAR VA threshold demand was 0.31±0.17 and 0.44±0.14 respectively. The mean distance VA demand (minimum) in front desk position was 0.56±0.18 logMAR. Increased distance threshold demand (logMAR range -0.06, 0.19) was noted in 7 classrooms (21%). The mean VA demand in grades 4 to 8 and grades 9 to 12 was 0.35±0.16 and 0.24±0.16 logMAR respectively and the difference was not statistically significant (p = 0.055). The distance from board to front desk was greater than the recommended standard of 2.2m in 27 classrooms (82%). The other measured parameters were noted to be different from the proposed standards in majority of the classrooms. The study suggests the inclusion of task demand assessment in school vision screening protocol to provide relevant guidance to school authorities. These findings can serve as evidence to accommodate children with mild to moderate visual impairment in the regular classrooms.

Estimating Allee Dynamics before They Can Be Observed: Polar Bears as a Case Study

PubMed Central

Molnár, Péter K.; Lewis, Mark A.; Derocher, Andrew E.

2014-01-01

Allee effects are an important component in the population dynamics of numerous species. Accounting for these Allee effects in population viability analyses generally requires estimates of low-density population growth rates, but such data are unavailable for most species and particularly difficult to obtain for large mammals. Here, we present a mechanistic modeling framework that allows estimating the expected low-density growth rates under a mate-finding Allee effect before the Allee effect occurs or can be observed. The approach relies on representing the mechanisms causing the Allee effect in a process-based model, which can be parameterized and validated from data on the mechanisms rather than data on population growth. We illustrate the approach using polar bears (Ursus maritimus), and estimate their expected low-density growth by linking a mating dynamics model to a matrix projection model. The Allee threshold, defined as the population density below which growth becomes negative, is shown to depend on age-structure, sex ratio, and the life history parameters determining reproduction and survival. The Allee threshold is thus both density- and frequency-dependent. Sensitivity analyses of the Allee threshold show that different combinations of the parameters determining reproduction and survival can lead to differing Allee thresholds, even if these differing combinations imply the same stable-stage population growth rate. The approach further shows how mate-limitation can induce long transient dynamics, even in populations that eventually grow to carrying capacity. Applying the models to the overharvested low-density polar bear population of Viscount Melville Sound, Canada, shows that a mate-finding Allee effect is a plausible mechanism for slow recovery of this population. Our approach is generalizable to any mating system and life cycle, and could aid proactive management and conservation strategies, for example, by providing a priori estimates of minimum conservation targets for rare species or minimum eradication targets for pests and invasive species. PMID:24427306

Functional Brain Networks: Does the Choice of Dependency Estimator and Binarization Method Matter?

NASA Astrophysics Data System (ADS)

Jalili, Mahdi

2016-07-01

The human brain can be modelled as a complex networked structure with brain regions as individual nodes and their anatomical/functional links as edges. Functional brain networks are constructed by first extracting weighted connectivity matrices, and then binarizing them to minimize the noise level. Different methods have been used to estimate the dependency values between the nodes and to obtain a binary network from a weighted connectivity matrix. In this work we study topological properties of EEG-based functional networks in Alzheimer’s Disease (AD). To estimate the connectivity strength between two time series, we use Pearson correlation, coherence, phase order parameter and synchronization likelihood. In order to binarize the weighted connectivity matrices, we use Minimum Spanning Tree (MST), Minimum Connected Component (MCC), uniform threshold and density-preserving methods. We find that the detected AD-related abnormalities highly depend on the methods used for dependency estimation and binarization. Topological properties of networks constructed using coherence method and MCC binarization show more significant differences between AD and healthy subjects than the other methods. These results might explain contradictory results reported in the literature for network properties specific to AD symptoms. The analysis method should be seriously taken into account in the interpretation of network-based analysis of brain signals.

Doses of Nearby Nature Simultaneously Associated with Multiple Health Benefits

PubMed Central

Cox, Daniel T. C.; Shanahan, Danielle F.; Hudson, Hannah L.; Fuller, Richard A.; Anderson, Karen; Hancock, Steven; Gaston, Kevin J.

2017-01-01

Exposure to nature provides a wide range of health benefits. A significant proportion of these are delivered close to home, because this offers an immediate and easily accessible opportunity for people to experience nature. However, there is limited information to guide recommendations on its management and appropriate use. We apply a nature dose-response framework to quantify the simultaneous association between exposure to nearby nature and multiple health benefits. We surveyed ca. 1000 respondents in Southern England, UK, to determine relationships between (a) nature dose type, that is the frequency and duration (time spent in private green space) and intensity (quantity of neighbourhood vegetation cover) of nature exposure and (b) health outcomes, including mental, physical and social health, physical behaviour and nature orientation. We then modelled dose-response relationships between dose type and self-reported depression. We demonstrate positive relationships between nature dose and mental and social health, increased physical activity and nature orientation. Dose-response analysis showed that lower levels of depression were associated with minimum thresholds of weekly nature dose. Nearby nature is associated with quantifiable health benefits, with potential for lowering the human and financial costs of ill health. Dose-response analysis has the potential to guide minimum and optimum recommendations on the management and use of nearby nature for preventative healthcare. PMID:28208789

Doses of Nearby Nature Simultaneously Associated with Multiple Health Benefits.

PubMed

Cox, Daniel T C; Shanahan, Danielle F; Hudson, Hannah L; Fuller, Richard A; Anderson, Karen; Hancock, Steven; Gaston, Kevin J

2017-02-09

Exposure to nature provides a wide range of health benefits. A significant proportion of these are delivered close to home, because this offers an immediate and easily accessible opportunity for people to experience nature. However, there is limited information to guide recommendations on its management and appropriate use. We apply a nature dose-response framework to quantify the simultaneous association between exposure to nearby nature and multiple health benefits. We surveyed ca. 1000 respondents in Southern England, UK, to determine relationships between (a) nature dose type, that is the frequency and duration (time spent in private green space) and intensity (quantity of neighbourhood vegetation cover) of nature exposure and (b) health outcomes, including mental, physical and social health, physical behaviour and nature orientation. We then modelled dose-response relationships between dose type and self-reported depression. We demonstrate positive relationships between nature dose and mental and social health, increased physical activity and nature orientation. Dose-response analysis showed that lower levels of depression were associated with minimum thresholds of weekly nature dose. Nearby nature is associated with quantifiable health benefits, with potential for lowering the human and financial costs of ill health. Dose-response analysis has the potential to guide minimum and optimum recommendations on the management and use of nearby nature for preventative healthcare.

Why Does Threshold Level Change in Transcranial Motor-evoked Potentials During Surgery for Supratentorial Lesions?

PubMed

Abboud, Tammam; Huckhagel, Torge; Stork, Jan-Henrich; Hamel, Wolfgang; Schwarz, Cindy; Vettorazzi, Eik; Westphal, Manfred; Martens, Tobias

2017-10-01

Rising threshold level during monitoring of motor-evoked potentials (MEP) using transcranial electrical stimulation (TES) has been described without damage to the motor pathway in the cranial surgery, suggesting the need for monitoring of affected and unaffected hemisphere. We aimed to determine the factors that lead to a change in threshold level and to establish reliable criteria for adjusting stimulation intensity during surgery for supratentorial lesions. Between October 2014 and October 2015, TES-MEP were performed in 143 patients during surgery for unilateral supratentorial lesions in motor-eloquent brain areas. All procedures were performed under general anesthesia using a strict protocol to maintain stable blood pressure. MEP were evaluated bilaterally to assess the percentage increase in threshold level, which was considered significant if it exceeded 20% on the contralateral side beyond the percentage increase on the ipsilateral side. Patients who developed a postoperative motor deficit were excluded. Volume of subdural air was measured on postoperative magnetic resonance imaging. Logistic regression was performed to identify factors associated with the intraoperative recorded changes in threshold level. A total of 123 patients were included in the study. On the affected side, 82 patients (66.7%) showed an increase in threshold level, which ranged from 2% to 48% and 41 patients (33.3%) did not show any change. The difference to the unaffected side was under 20% in all patients. The recorded range of changes in the systolic and mean pressure did not exceed 20 mm Hg in any of the patients. Pneumocephalus was detected on postoperative magnetic resonance imaging scans in 87 patients (70.7%) and 81 of them (93.1%) had an intraoperative increase in threshold level on either sides. Pneumocephalus was the only factor associated with an increase in threshold level on the affected side (P<0.001), while each of pneumocephalus and length of the procedure correlated with a change in threshold level on the unaffected side (P<0.001 and 0.032, respectively). Pneumocephalus was the only factor associated with increase in threshold level during MEP monitoring without damaging motor pathway. Threshold level on the affected side can rise up to 48% without being predictive of postoperative paresis, as long as the difference between the increased threshold of the affected and unaffected side is within 20%. Changes in systolic or mean blood pressure within a range of 20 mm Hg do not seem to influence intraoperative MEP.

Which type of leader do I support in step-level public good dilemmas? The roles of level of threshold and trust.

PubMed

De Cremer, David

2007-02-01

The present research examined the moderating effect of the level of threshold on people's preferences for different leader types in step-level public good dilemmas. It was assumed that the primary focus of people in step-level public good dilemmas is to make sure that the group surpasses the threshold. Consequently, when the level of threshold is difficult to reach people are expected to provide more support for and cooperate with a leader that monitors and controls the contributions made toward the public good. However, if the threshold is easy to surpass people will focus more on whether the obtained public good or bonus will be distributed according to agreements, suggesting that people will provide more support to and cooperate with a leader that monitors and controls the distribution of the bonus. These predictions were confirmed across two experiments using a step-level public good paradigm with a dichotomous (Study 1) and a continuous (Study 2) contribution choice. Moreover, the results also revealed that perceptions of trust accounted, in part, for the effect of level of threshold on people's leadership preferences.

Sensitivity of Tropical Cyclones to Parameterized Convection in the NASA GEOS5 Model

NASA Technical Reports Server (NTRS)

Lim, Young-Kwon; Schubert, Siegfried D.; Reale, Oreste; Lee, Myong-In; Molod, Andrea M.; Suarez, Max J.

2014-01-01

The sensitivity of tropical cyclones (TCs) to changes in parameterized convection is investigated to improve the simulation of TCs in the North Atlantic. Specifically, the impact of reducing the influence of the Relaxed Arakawa-Schubert (RAS) scheme-based parameterized convection is explored using the Goddard Earth Observing System version5 (GEOS5) model at 0.25 horizontal resolution. The years 2005 and 2006 characterized by very active and inactive hurricane seasons, respectively, are selected for simulation. A reduction in parameterized deep convection results in an increase in TC activity (e.g., TC number and longer life cycle) to more realistic levels compared to the baseline control configuration. The vertical and horizontal structure of the strongest simulated hurricane shows the maximum lower-level (850-950hPa) wind speed greater than 60 ms and the minimum sea level pressure reaching 940mb, corresponding to a category 4 hurricane - a category never achieved by the control configuration. The radius of the maximum wind of 50km, the location of the warm core exceeding 10 C, and the horizontal compactness of the hurricane center are all quite realistic without any negatively affecting the atmospheric mean state. This study reveals that an increase in the threshold of minimum entrainment suppresses parameterized deep convection by entraining more dry air into the typical plume. This leads to cooling and drying at the mid- to upper-troposphere, along with the positive latent heat flux and moistening in the lower-troposphere. The resulting increase in conditional instability provides an environment that is more conducive to TC vortex development and upward moisture flux convergence by dynamically resolved moist convection, thereby increasing TC activity.

Winter ventilation rates at primary schools: comparison between Portugal and Finland.

PubMed

Canha, N; Almeida, S M; Freitas, M C; Täubel, M; Hänninen, O

2013-01-01

This study focused on examination of ventilation rates in classrooms with two different types of ventilation systems: natural and mechanical. Carbon dioxide (CO2) measurements were conducted in primary schools of Portugal characterized by natural ventilation and compared to Finland where mechanical ventilation is the norm. The winter period was selected since this season exerts a great influence in naturally ventilated classrooms, where opening of windows and doors occurs due to outdoor atmospheric conditions. The ventilation rates were calculated by monitoring CO2 concentrations generated by the occupants (used as a tracer gas) and application of the buildup phase method. A comparison between both countries' results was conducted with respect to ventilation rates and how these levels corresponded to national regulatory standards. Finnish primary schools (n = 2) registered a mean ventilation rate of 13.3 L/s per person, which is higher than the recommended ventilation standards. However, the Finnish classroom that presented the lowest ventilation rate (7.2 L/s per person) displayed short-term CO2 levels above 1200 ppm, which is the threshold limit value (TLV) recommended by national guidelines. The Portuguese classrooms (n = 2) showed low ventilation rates with mean values of 2.4 L/s per person, which is markedly lower than the minimum recommended value of 7 L/s per person as defined by ASHRAE and 20% less than the REHVA minimum of 3 L/s per person. Carbon dioxide levels of 1000 ppm, close to the TLV of 1200 ppm, were also reached in both Portuguese classrooms studied. The situation in Portugal indicates a potentially serious indoor air quality problem and strengthens the need for intervention to improve ventilation rates in naturally ventilated classrooms.

Oxygen at Nanomolar Levels Reversibly Suppresses Process Rates and Gene Expression in Anammox and Denitrification in the Oxygen Minimum Zone off Northern Chile

PubMed Central

Stewart, Frank J.; Thamdrup, Bo; De Brabandere, Loreto; Revsbech, Niels Peter; Ulloa, Osvaldo; Canfield, Don E.; DeLong, Edward F.

2014-01-01

ABSTRACT A major percentage (20 to 40%) of global marine fixed-nitrogen loss occurs in oxygen minimum zones (OMZs). Concentrations of O2 and the sensitivity of the anaerobic N2-producing processes of anammox and denitrification determine where this loss occurs. We studied experimentally how O2 at nanomolar levels affects anammox and denitrification rates and the transcription of nitrogen cycle genes in the anoxic OMZ off Chile. Rates of anammox and denitrification were reversibly suppressed, most likely at the enzyme level. Fifty percent inhibition of N2 and N2O production by denitrification was achieved at 205 and 297 nM O2, respectively, whereas anammox was 50% inhibited at 886 nM O2. Coupled metatranscriptomic analysis revealed that transcripts encoding nitrous oxide reductase (nosZ), nitrite reductase (nirS), and nitric oxide reductase (norB) decreased in relative abundance above 200 nM O2. This O2 concentration did not suppress the transcription of other dissimilatory nitrogen cycle genes, including nitrate reductase (narG), hydrazine oxidoreductase (hzo), and nitrite reductase (nirK). However, taxonomic characterization of transcripts suggested inhibition of narG transcription in gammaproteobacteria, whereas the transcription of anammox narG, whose gene product is likely used to oxidatively replenish electrons for carbon fixation, was not inhibited. The taxonomic composition of transcripts differed among denitrification enzymes, suggesting that distinct groups of microorganisms mediate different steps of denitrification. Sulfide addition (1 µM) did not affect anammox or O2 inhibition kinetics but strongly stimulated N2O production by denitrification. These results identify new O2 thresholds for delimiting marine nitrogen loss and highlight the utility of integrating biogeochemical and metatranscriptomic analyses. PMID:25352619

Global climatic changes during the Devonian-Mississippian: Stable isotope biogeochemistry of brachiopods

NASA Astrophysics Data System (ADS)

Brand, Uwe

1989-12-01

A progressive trend towards heavier δ 13C values of Devonian-Mississippian brachiopods from North America, Europe, Afghanistan and Algeria probably reflects expansion of the terrestrestrial and/or marine biomass and/or burial of carbon in soils/sediments. Oceanic Productivity crises, based on perturbations in the overall δ 13C trend, are recognized for the Mid Givetian, Early Famennian, Late Kinderhookian, Late Osagean and Early and Late Meramecian. The Givetian productivity crisis was probably accompanied by massive overturn of biologically toxic deep-ocean water. Temperature data, adjusted for the possible secular variation of seawater, support the hypothesis of global greenhouse conditions for the Devonian (mean of 30°C, mean of 26°C if extrinsic data are deleted) and icehouse conditions for the Mississippian (mean of 17°C). During the Mid Givetian, Frasnian and Early Famennian calculated water temperatures for tropical epeiric seas were generally above the thermal threshold limit (˜ 38°C) of most marine invertebrates or epeiric seawater was characterized by unusually low salinities (˜ pp ppt) or a combination of the two. These elevated water temperatures and/or low salinities, in conjunction with the postulated productivity crises and overturning of toxic deep waters are considered prime causes for the biotic crisis of the Late Devonian. In addition, a presumed expanding oxygen-minimum zone and general anoxia in the oceans prevented shallow-water organisms from escaping these inhospitable conditions. Re-population of the tropical seas occurred, after either water temperatures had dropped below the thermal threshold limit and/or salinities were back to normal, and oceanic productivity had increased due to more vigorous oceanic circulation, sometime during the Mid-Late Famennian. Migration of eurythermal, shallow- and deeper-water organisms into the vacant niches of the shallow seas was possible because of, generally, slightly lower sea levels, but, more importantly of more restricted oxygen-minimum zone and generally reduced oceanic anoxia.

Evaluating the U.S. Food Safety Modernization Act Produce Safety Rule Standard for Microbial Quality of Agricultural Water for Growing Produce.

PubMed

Havelaar, Arie H; Vazquez, Kathleen M; Topalcengiz, Zeynal; Muñoz-Carpena, Rafael; Danyluk, Michelle D

2017-10-09

The U.S. Food and Drug Administration (FDA) has defined standards for the microbial quality of agricultural surface water used for irrigation. According to the FDA produce safety rule (PSR), a microbial water quality profile requires analysis of a minimum of 20 samples for Escherichia coli over 2 to 4 years. The geometric mean (GM) level of E. coli should not exceed 126 CFU/100 mL, and the statistical threshold value (STV) should not exceed 410 CFU/100 mL. The water quality profile should be updated by analysis of a minimum of five samples per year. We used an extensive set of data on levels of E. coli and other fecal indicator organisms, the presence or absence of Salmonella, and physicochemical parameters in six agricultural irrigation ponds in West Central Florida to evaluate the empirical and theoretical basis of this PSR. We found highly variable log-transformed E. coli levels, with standard deviations exceeding those assumed in the PSR by up to threefold. Lognormal distributions provided an acceptable fit to the data in most cases but may underestimate extreme levels. Replacing censored data with the detection limit of the microbial tests underestimated the true variability, leading to biased estimates of GM and STV. Maximum likelihood estimation using truncated lognormal distributions is recommended. Twenty samples are not sufficient to characterize the bacteriological quality of irrigation ponds, and a rolling data set of five samples per year used to update GM and STV values results in highly uncertain results and delays in detecting a shift in water quality. In these ponds, E. coli was an adequate predictor of the presence of Salmonella in 150-mL samples, and turbidity was a second significant variable. The variability in levels of E. coli in agricultural water was higher than that anticipated when the PSR was finalized, and more detailed information based on mechanistic modeling is necessary to develop targeted risk management strategies.

SU-E-J-242: Volume-Dependence of Quantitative Imaging Features From CT and CE-CT Images of NSCLC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fave, X; Fried, D; UT Health Science Center Graduate School of Biomedical Sciences, Houston, TX

Purpose: To determine whether tumor volume plays a significant role in the values obtained for texture features when they are extracted from computed tomography (CT) images of non-small cell lung cancer (NSCLC). We also sought to identify whether features can be reliably measured at all volumes or if a minimum volume threshold should be recommended. Methods: Eleven features were measured on 40 CT and 32 contrast-enhanced CT (CECT) patient images for this study. Features were selected for their prognostic/diagnostic value in previous publications. Direct correlations between these textures and volume were evaluated using the Spearman correlation coefficient. Any texture thatmore » the Wilcoxon rank-sum test was used to compare the variation above and below a volume cutoff. Four different volume thresholds (5, 10, 15, and 20 cm{sup 3}) were tested. Results: Four textures were found to be significantly correlated with volume in both the CT and CE-CT images. These were busyness, coarseness, gray-level nonuniformity, and run-length nonuniformity with correlation coefficients of 0.92, −0.96, 0.94, and 0.98 for the CT images and 0.95, −0.97, 0.98, and 0.98 for the CE-CT images. After volume normalization, the correlation coefficients decreased substantially. For the data obtained from the CT images, the results of the Wilcoxon rank-sum test were significant when volume thresholds of 5–15 cm3 were used. No volume threshold was shown to be significant for the CE-CT data. Conclusion: Equations for four features that have been used in several published studies were found to be volume-dependent. Future studies should consider implementing normalization factors or removing these features entirely to prevent this potential source of redundancy or bias. This work was supported in part by National Cancer Institute grant R03CA178495-01. Xenia Fave is a recipient of the American Association of Physicists in Medicine Graduate Fellowship.« less

SU-F-R-11: Designing Quality and Safety Informatics Through Implementation of a CT Radiation Dose Monitoring Program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilson, JM; Samei, E; Departments of Physics, Electrical and Computer Engineering, and Biomedical Engineering, and Medical Physics Graduate Program, Duke University, Durham, NC

2016-06-15

Purpose: Recent legislative and accreditation requirements have driven rapid development and implementation of CT radiation dose monitoring solutions. Institutions must determine how to improve quality, safety, and consistency of their clinical performance. The purpose of this work was to design a strategy and meaningful characterization of results from an in-house, clinically-deployed dose monitoring solution. Methods: A dose monitoring platform was designed by our imaging physics group that focused on extracting protocol parameters, dose metrics, and patient demographics and size. Compared to most commercial solutions, which focus on individual exam alerts and global thresholds, the program sought to characterize overall consistencymore » and targeted thresholds based on eight analytic interrogations. Those were based on explicit questions related to protocol application, national benchmarks, protocol and size-specific dose targets, operational consistency, outliers, temporal trends, intra-system variability, and consistent use of electronic protocols. Using historical data since the start of 2013, 95% and 99% intervals were used to establish yellow and amber parameterized dose alert thresholds, respectively, as a function of protocol, scanner, and size. Results: Quarterly reports have been generated for three hospitals for 3 quarters of 2015 totaling 27880, 28502, 30631 exams, respectively. Four adult and two pediatric protocols were higher than external institutional benchmarks. Four protocol dose levels were being inconsistently applied as a function of patient size. For the three hospitals, the minimum and maximum amber outlier percentages were [1.53%,2.28%], [0.76%,1.8%], [0.94%,1.17%], respectively. Compared with the electronic protocols, 10 protocols were found to be used with some inconsistency. Conclusion: Dose monitoring can satisfy requirements with global alert thresholds and patient dose records, but the real value is in optimizing patient-specific protocols, balancing image quality trade-offs that dose-reduction strategies promise, and improving the performance and consistency of a clinical operation. Data plots that capture patient demographics and scanner performance demonstrate that value.« less

Optimization of micromachined membrane switches

NASA Astrophysics Data System (ADS)

Hiltmann, Kai; Lang, Walter

1997-09-01

We have determined the minimum dimensions for micromachined membrane switches in several experiments, both regarding the strength of the membranes themselves and the elongations required for safe switching performance. Based on these data, pressure switches for voltages of 10 - 100 V were made as single and multiple elements and tested. Test results, with scatter of pressure threshold data in the ten per cent range, prove very encouraging for further development.

Threshold to Transfer Writing Skills from L1 to L2

ERIC Educational Resources Information Center

Ito, Fumihiko

2009-01-01

Background: It has been hypothesized that L2 (second language) readers are not able to draw on their L1 (first language) reading skills for the successful development of L2 reading skills until they develop a certain proficiency in L2 because a lack of proficiency blocks transfer of L1 reading skills to the reading of L2 texts. This minimum degree…

Accreditation of Prior Learning as a Lever for Lifelong Learning: Lessons Learnt from the New Opportunities Initiative, Portugal

ERIC Educational Resources Information Center

Carneiro, Roberto, Ed.

2011-01-01

The New Opportunities Initiative (NOI) is a Portuguese flagship programme to recognise and accredit prior learning (RPL, APL) and to endow low-skilled adults with upper secondary qualifications, which is defined as the minimum entry threshold to the exercise of a full citizenship in a knowledge-rich society. NOI's major achievement has been its…

The fragmentation threshold and implications for explosive eruptions

NASA Astrophysics Data System (ADS)

Kennedy, B.; Spieler, O.; Kueppers, U.; Scheu, B.; Mueller, S.; Taddeucci, J.; Dingwell, D.

2003-04-01

The fragmentation threshold is the minimum pressure differential required to cause a porous volcanic rock to form pyroclasts. This is a critical parameter when considering the shift from effusive to explosive eruptions. We fragmented a variety of natural volcanic rock samples at room temperature (20oC) and high temperature (850oC) using a shock tube modified after Aldibirov and Dingwell (1996). This apparatus creates a pressure differential which drives fragmentation. Pressurized gas in the vesicles of the rock suddenly expands, blowing the sample apart. For this reason, the porosity is the primary control on the fragmentation threshold. On a graph of porosity against fragmentation threshold, our results from a variety of natural samples at both low and high temperatures all plot on the same curve and show the threshold increasing steeply at low porosities. A sharp decrease in the fragmentation threshold occurs as porosity increases from 0- 15%, while a more gradual decrease is seen from 15- 85%. The high temperature experiments form a curve with less variability than the low temperature experiments. For this reason, we have chosen to model the high temperature thresholds. The curve can be roughly predicted by the tensile strength of glass (140 MPa) divided by the porosity. Fractured phenocrysts in the majority of our samples reduces the overall strength of the sample. For this reason, the threshold values can be more accurately predicted by % matrix x the tensile strength/ porosity. At very high porosities the fragmentation threshold varies significantly due to the effect of bubble shape and size distributions on the permeability (Mueller et al, 2003). For example, high thresholds are seen for samples with very high permeabilities, where gas flow reduces the local pressure differential. These results allow us to predict the fragmentation threshold for any volcanic rock for which the porosity and crystal contents are known. During explosive eruptions, the fragmentation threshold may be exceeded in two ways: (1) by building an overpressure within the vesicles above the fragmentation threshold or (2) by unloading and exposing lithostatically pressurised magma to lower pressures. Using this data, we can in principle estimate the height of dome collapse or amount of overpressure necessary to produce an explosive eruption.

Effects of reference analgesics and psychoactive drugs on the noxious heat threshold of mice measured by an increasing-temperature water bath.

PubMed

Boros, Melinda; Benkó, Rita; Bölcskei, Kata; Szolcsányi, János; Barthó, Loránd; Pethő, Gábor

2013-12-01

The study aimed at validating an increasing-temperature water bath suitable for determining the noxious heat threshold for use in mice. The noxious heat threshold was determined by immersing the tail of the gently held awake mouse into a water container whose temperature was near-linearly increased at a rate of 24°C/min. until the animal withdrew its tail, that is, heating attained the noxious threshold. The effects of standard analgesic, neuroleptic and anxiolytic drugs were investigated in a parallel way on both the noxious heat threshold and the psychomotor activity assessed by the open field test. Morphine, diclofenac and metamizol (dipyrone) elevated the heat threshold of mice with minimum effective doses of 6, 30 and 1000 mg/kg i.p., respectively. These doses of morphine and diclofenac failed to induce any remarkable effect on psychomotor activity in the open field test while that of metamizol exerted a profound inhibition. The anxiolytic diazepam and the neuroleptic droperidol at doses evoking a mild and moderate, respectively, psychomotor inhibition failed to alter the heat threshold. Combination of a subliminal dose of morphine (regarding both antinociceptive and psychomotor inhibitory action) with diclofenac, metamizol, diazepam or droperidol at doses also subliminal regarding the thermal antinociceptive effect elevated the noxious heat threshold without major additional effects in the open field test. It is concluded that the increasing-temperature water bath is suitable for studying the thermal antinociceptive effects of morphine and diclofenac as well as the morphine-sparing action of diclofenac, metamizol, droperidol and diazepam. Behavioural testing is recommended when testing analgesics. © 2013 Nordic Pharmacological Society. Published by John Wiley & Sons Ltd.

R-on-1 automatic mapping: A new tool for laser damage testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hue, J.; Garrec, P.; Dijon, J.

1996-12-31

Laser damage threshold measurement is statistical in nature. For a commercial qualification or for a user, the threshold determined by the weakest point is a satisfactory characterization. When a new coating is designed, threshold mapping is very useful. It enables the technology to be improved and followed more accurately. Different statistical parameters such as the minimum, maximum, average, and standard deviation of the damage threshold as well as spatial parameters such as the threshold uniformity of the coating can be determined. Therefore, in order to achieve a mapping, all the tested sites should give data. This is the major interestmore » of the R-on-1 test in spite of the fact that the laser damage threshold obtained by this method may be different from the 1-on-1 test (smaller or greater). Moreover, on the damage laser test facility, the beam size is smaller (diameters of a few hundred micrometers) than the characteristic sizes of the components in use (diameters of several centimeters up to one meter). Hence, a laser damage threshold mapping appears very interesting, especially for applications linked to large optical components like the Megajoule project or the National Ignition Facility (N.I.F). On the test bench used, damage detection with a Nomarski microscope and scattered light measurement are almost equivalent. Therefore, it becomes possible to automatically detect on line the first defects induced by YAG irradiation. Scattered light mappings and laser damage threshold mappings can therefore be achieved using a X-Y automatic stage (where the test sample is located). The major difficulties due to the automatic capabilities are shown. These characterizations are illustrated at 355 nm. The numerous experiments performed show different kinds of scattering curves, which are discussed in relation with the damage mechanisms.« less

The Relationship between the Behavioral Hearing Thresholds and Maximum Bilirubin Levels at Birth in Children with a History of Neonatal Hyperbilirubinemia

PubMed Central

Panahi, Rasool; Jafari, Zahra; Sheibanizade, Abdoreza; Salehi, Masoud; Esteghamati, Abdoreza; Hasani, Sara

2013-01-01

Introduction: Neonatal hyperbilirubinemia is one of the most important factors affecting the auditory system and can cause sensorineural hearing loss. This study investigated the relationship between behavioral hearing thresholds in children with a history of jaundice and the maximum level of bilirubin concentration in the blood. Materials and Methods: This study was performed on 18 children with a mean age of 5.6 years and with a history of neonatal hyperbilirubinemia. Behavioral hearing thresholds, transient evoked emissions and brainstem evoked responses were evaluated in all children. Results: Six children (33.3%) had normal hearing thresholds and the remaining (66.7%) had some degree of hearing loss. There was no significant relationship (r=-0.28, P=0.09) between the mean total bilirubin levels and behavioral hearing thresholds in all samples. A transient evoked emission was seen only in children with normal hearing thresholds however in eight cases brainstem evoked responses had not detected. Conclusion: Increased blood levels of bilirubin at the neonatal period were potentially one of the causes of hearing loss. There was a lack of a direct relationship between neonatal bilirubin levels and the average hearing thresholds which emphasizes on the necessity of monitoring the various amounts of bilirubin levels. PMID:24303432

Model for Estimating the Threshold Mechanical Stability of Structural Cartilage Grafts Used in Rhinoplasty

PubMed Central

Zemek, Allison; Garg, Rohit; Wong, Brian J. F.

2014-01-01

Objectives/Hypothesis Characterizing the mechanical properties of structural cartilage grafts used in rhinoplasty is valuable because softer engineered tissues are more time- and cost-efficient to manufacture. The aim of this study is to quantitatively identify the threshold mechanical stability (e.g., Young’s modulus) of columellar, L-strut, and alar cartilage replacement grafts. Study Design Descriptive, focus group survey. Methods Ten mechanical phantoms of identical size (5 × 20 × 2.3 mm) and varying stiffness (0.360 to 0.85 MPa in 0.05 MPa increments) were made from urethane. A focus group of experienced rhinoplasty surgeons (n = 25, 5 to 30 years in practice) were asked to arrange the phantoms in order of increasing stiffness. Then, they were asked to identify the minimum acceptable stiffness that would still result in favorable surgical outcomes for three clinical applications: columellar, L-strut, and lateral crural replacement grafts. Available surgeons were tested again after 1 week to evaluate intra-rater consistency. Results For each surgeon, the threshold stiffness for each clinical application differed from the threshold values derived by logistic regression by no more than 0.05 MPa (accuracy to within 10%). Specific thresholds were 0.56, 0.59, and 0.49 MPa for columellar, L-strut, and alar grafts, respectively. For comparison, human nasal septal cartilage is approximately 0.8 MPa. Conclusions There was little inter- and intra-rater variation of the identified threshold values for adequate graft stiffness. The identified threshold values will be useful for the design of tissue-engineered or semisynthetic cartilage grafts for use in structural nasal surgery. PMID:20513022

Retinal injury thresholds for 532, 578, and 630 nm lasers in connection to photodynamic therapy for choroidal neovascularization.

PubMed

Chen, Hongxia; Yang, Zaifu; Zou, Xianbiao; Wang, Jiarui; Zhu, Jianguo; Gu, Ying

2014-01-01

The purpose of this study was to explore the retinal injury thresholds in rabbits and evaluate the influence of retinal pigmentation on threshold irradiance at laser wavelengths of 532, 578, and 630 nm which might be involved in hypocrellin B (HB) and hematoporphyrin monomethyl ether (HMME) photodynamic therapy (PDT) for choroidal neovascularization (CNV). The eyes of pigmented and non-pigmented rabbits were exposed to 532, 578, and 630 nm lasers coupled to a slit lamp biological microscope. The exposure duration was 100 seconds and the retinal spot size was 2 mm throughout the experiment. The minimum visible lesions were detected by funduscopy at 1 and 24 hours post exposure. Bliss probit analysis was performed to determine the ED50 thresholds, fiducial limits and probit slope. In pigmented rabbits, the 24-hour retinal threshold irradiances at 532, 578, and 630 nm were 1,003, 1,475, and 1,720 mW/cm(2) , respectively. In non-pigmented rabbits, the 24-hour threshold irradiances were 1,657, 1,865, and 15,360 mW/cm(2) , respectively. The ED50 for 24-hour observation differed very little from the ED50 for 1-hour observation. The non-pigmented rabbits required a ninefold increase in threshold irradiance at 630 nm comparing to the pigmented rabbits. This study will contribute to the knowledge base for the limits of laser irradiance in application of HB or HMME PDT for CNV. © 2013 Wiley Periodicals, Inc.

Comparison of image segmentation of lungs using methods: connected threshold, neighborhood connected, and threshold level set segmentation

NASA Astrophysics Data System (ADS)

Amanda, A. R.; Widita, R.

2016-03-01

The aim of this research is to compare some image segmentation methods for lungs based on performance evaluation parameter (Mean Square Error (MSE) and Peak Signal Noise to Ratio (PSNR)). In this study, the methods compared were connected threshold, neighborhood connected, and the threshold level set segmentation on the image of the lungs. These three methods require one important parameter, i.e the threshold. The threshold interval was obtained from the histogram of the original image. The software used to segment the image here was InsightToolkit-4.7.0 (ITK). This research used 5 lung images to be analyzed. Then, the results were compared using the performance evaluation parameter determined by using MATLAB. The segmentation method is said to have a good quality if it has the smallest MSE value and the highest PSNR. The results show that four sample images match the criteria of connected threshold, while one sample refers to the threshold level set segmentation. Therefore, it can be concluded that connected threshold method is better than the other two methods for these cases.

Safety limit warning levels for the avoidance of excessive sound amplification to protect against further hearing loss.

PubMed

Johnson, Earl E

2017-11-01

To determine safe output sound pressure levels (SPL) for sound amplification devices to preserve hearing sensitivity after usage. A mathematical model consisting of the Modified Power Law (MPL) (Humes & Jesteadt, 1991 ) combined with equations for predicting temporary threshold shift (TTS) and subsequent permanent threshold shift (PTS) (Macrae, 1994b ) was used to determine safe output SPL. The study involves no new human subject measurements of loudness tolerance or threshold shifts. PTS was determined by the MPL model for 234 audiograms and the SPL output recommended by four different validated prescription recommendations for hearing aids. PTS can, on rare occasion, occur as a result of SPL delivered by hearing aids at modern day prescription recommendations. The trading relationship of safe output SPL, decibel hearing level (dB HL) threshold, and PTS was captured with algebraic expressions. Better hearing thresholds lowered the safe output SPL and higher thresholds raised the safe output SPL. Safe output SPL can consider the magnitude of unaided hearing loss. For devices not set to prescriptive levels, limiting the output SPL below the safe levels identified should protect against threshold worsening as a result of long-term usage.

Underwater temporary threshold shift in pinnipeds: effects of noise level and duration.

PubMed

Kastak, David; Southall, Brandon L; Schusterman, Ronald J; Kastak, Colleen Reichmuth

2005-11-01

Behavioral psychophysical techniques were used to evaluate the residual effects of underwater noise on the hearing sensitivity of three pinnipeds: a California sea lion (Zalophus californianus), a harbor seal (Phoca vitulina), and a northern elephant seal (Mirounga angustirostris). Temporary threshold shift (TTS), defined as the difference between auditory thresholds obtained before and after noise exposure, was assessed. The subjects were exposed to octave-band noise centered at 2500 Hz at two sound pressure levels: 80 and 95 dB SL (re: auditory threshold at 2500 Hz). Noise exposure durations were 22, 25, and 50 min. Threshold shifts were assessed at 2500 and 3530 Hz. Mean threshold shifts ranged from 2.9-12.2 dB. Full recovery of auditory sensitivity occurred within 24 h of noise exposure. Control sequences, comprising sham noise exposures, did not result in significant mean threshold shifts for any subject. Threshold shift magnitudes increased with increasing noise sound exposure level (SEL) for two of the three subjects. The results underscore the importance of including sound exposure metrics (incorporating sound pressure level and exposure duration) in order to fully assess the effects of noise on marine mammal hearing.

Neues "Francais fondamental?" Das Europa-Projekt "Un niveau seuil." (A New "Francais fondamental?" The European Project "A Threshold Level").

ERIC Educational Resources Information Center

Raasch, Albert

1978-01-01

The project "Threshold Level," initiated by the Council of Europe in 1976, is compared with "Francais fondamental," comparing their aims and their differences. Offered as an interim statement, the article leaves open the question of whether Francais fondamental should be replaced by the the Threshold Level. (IFS/WGA)

Reliability of the method of levels for determining cutaneous temperature sensitivity

NASA Astrophysics Data System (ADS)

Jakovljević, Miroljub; Mekjavić, Igor B.

2012-09-01

Determination of the thermal thresholds is used clinically for evaluation of peripheral nervous system function. The aim of this study was to evaluate reliability of the method of levels performed with a new, low cost device for determining cutaneous temperature sensitivity. Nineteen male subjects were included in the study. Thermal thresholds were tested on the right side at the volar surface of mid-forearm, lateral surface of mid-upper arm and front area of mid-thigh. Thermal testing was carried out by the method of levels with an initial temperature step of 2°C. Variability of thermal thresholds was expressed by means of the ratio between the second and the first testing, coefficient of variation (CV), coefficient of repeatability (CR), intraclass correlation coefficient (ICC), mean difference between sessions (S1-S2diff), standard error of measurement (SEM) and minimally detectable change (MDC). There were no statistically significant changes between sessions for warm or cold thresholds, or between warm and cold thresholds. Within-subject CVs were acceptable. The CR estimates for warm thresholds ranged from 0.74°C to 1.06°C and from 0.67°C to 1.07°C for cold thresholds. The ICC values for intra-rater reliability ranged from 0.41 to 0.72 for warm thresholds and from 0.67 to 0.84 for cold thresholds. S1-S2diff ranged from -0.15°C to 0.07°C for warm thresholds, and from -0.08°C to 0.07°C for cold thresholds. SEM ranged from 0.26°C to 0.38°C for warm thresholds, and from 0.23°C to 0.38°C for cold thresholds. Estimated MDC values were between 0.60°C and 0.88°C for warm thresholds, and 0.53°C and 0.88°C for cold thresholds. The method of levels for determining cutaneous temperature sensitivity has acceptable reliability.

Landsat 8 and ICESat-2: Performance and potential synergies for quantifying dryland ecosystem vegetation cover and biomass

USGS Publications Warehouse

Glenn, Nancy F.; Neuenschwander, Amy; Vierling, Lee A.; Spaete, Lucas; Li, Aihua; Shinneman, Douglas; Pilliod, David S.; Arkle, Robert; McIlroy, Susan

2016-01-01

To estimate the potential synergies of OLI and ICESat-2 we used simulated ICESat-2 photon data to predict vegetation structure. In a shrubland environment with a vegetation mean height of 1 m and mean vegetation cover of 33%, vegetation photons are able to explain nearly 50% of the variance in vegetation height. These results, and those from a comparison site, suggest that a lower detection threshold of ICESat-2 may be in the range of 30% canopy cover and roughly 1 m height in comparable dryland environments and these detection thresholds could be used to combine future ICESat-2 photon data with OLI spectral data for improved vegetation structure. Overall, the synergistic use of Landsat 8 and ICESat-2 may improve estimates of above-ground biomass and carbon storage in drylands that meet these minimum thresholds, increasing our ability to monitor drylands for fuel loading and the potential to sequester carbon.

Effect of Strain Field on Threshold Displacement Energy of Tungsten Studied by Molecular Dynamics Simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Dong; Gao, Ning; Setyawan, W.

The influence of strain field on defect formation energy and threshold displacement energy (Ed) in body-centered cubic (BCC) tungsten (W) has been studied with molecular dynamics simulations. Two different W potentials (Fikar and Juslin) were compared and the results indicate that the connection distance and selected function linking the short-range and long-range portions of the potentials affects the threshold displacement energy and its direction-specific values. The minimum Ed direction calculated with the Fikar-potential is <100> and with the Juslin-potential is <111>. Nevertheless, the most stable self-interstitial configuration is found to be a <111>-crowdion for both potentials. This stable configuration doesmore » not change with applied strain. Varying the strain from compression to tension increases the vacancy formation energy but decreases the self-interstitial formation energy. The formation energy of a self-interstitial changes more significantly than a vacancy such that Ed decreases with applied hydrostatic strain from compression to tension.« less

Detection of sub micro Gray dose levels using OSL phosphor LiMgPO4:Tb,B

NASA Astrophysics Data System (ADS)

Rawat, N. S.; Dhabekar, Bhushan; Muthe, K. P.; Koul, D. K.; Datta, D.

2017-04-01

Detection of sub micro Gray doses finds application in personnel and environmental monitoring, and nuclear forensics. Recently developed LiMgPO4:Tb,B (LMP) is highly sensitive Optically Stimulated Luminescence (OSL) phosphor with excellent dosimetric properties. The OSL emission spectrum of LMP consists of several peaks attributed to characteristic Tb3+ emission. The OSL emission peak at 380 nm is favorable for bi-alkali PMT used in RISO reader system. It is demonstrated that significant improvement in dose detection threshold can be realized for LMP by optimization of continuous wave (CW-) OSL parameters like stimulation intensity and readout time. The minimum measurable dose (MMD) as low as 0.49 μGy in readout time of less than 1 s at stimulation intensity of 32 mW/cm2 has been achieved using this phosphor. The recommendations for choice of parameters for personnel and environmental monitoring are also discussed.

Performance analysis of microcomputer based differential protection of UHV lines under selective phase switching

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhatti, A.A.

1990-04-01

This paper examines the effects of primary and secondary fault quantities as well s of mutual couplings of neighboring circuits on the sensitivity of operation and threshold settings of a microcomputer based differential protection of UHV lines under selective phase switching. Microcomputer based selective phase switching allows the disconnection of minimum number of phases involved in a fault and requires the autoreclosing of these phases immediately after the extinction of secondary arc. During a primary fault a heavy current contribution to the healthy phases tends to cause an unwanted tripping. Faulty phases physically disconnected constitute an isolated fault which beingmore » coupled to the system affects the current and voltage levels of the healthy phases still retained in the system and may cause an unwanted tripping. The microcomputer based differential protection, appears to have poor performance when applied to uncompensated lines employing selective pole switching.« less

Reliability of the individual components of the Canadian Armed Forces Physical Employment Standard.

PubMed

Stockbrugger, Barry G; Reilly, Tara J; Blacklock, Rachel E; Gagnon, Patrick J

2018-01-29

This investigation recruited 24 participants from both the Canadian Armed Forces (CAF) and civilian populations to complete 4 separate trials at "best effort" of each of the 4 components in the CAF Physical Employment Standard named the FORCE Evaluation: Fitness for Operational Requirements of CAF Employment. Analyses were performed to examine the level of variability and reliability within each component. The results demonstrate that candidates should be provided with at least 1 retest if they have recently completed at least 2 previous best effort attempts as per the protocol. In addition, the minimal detectable difference is given for each of the 4 components in seconds which identifies the threshold for subsequent action, either retest or remedial training, for those unable to meet the minimum standard. These results will educate the delivery of this employment standard, function as a method of accommodation, in addition to providing direction for physical training programs.

The airborne infrared scanner as a geophysical research tool

USGS Publications Warehouse

Friedman, Jules D.

1970-01-01

The infrared scanner is proving to be an effective anomaly-mapping tool, albeit one which depicts surface emission directly and heat mass transfer from depths only indirectly and at a threshold level 50 to 100 times the normal conductive heat flow of the earth. Moreover, successive terrain observations are affected by time-dependent variables such as the diurnal and seasonal warming and cooling cycle of a point on the earth's surface. In planning precise air borne surveys of radiant flux from the earth's surface, account must be taken of background noise created by variations in micrometeorological factors and emissivity of surface materials, as well as the diurnal temperature cycle. The effect of the diurnal cycle may be minimized by planning predawn aerial surveys. In fact, the diurnal change is very small for most water bodies and the emissivity factor for water (e) =~ 1 so a minimum background noise is characteristic of scanner records of calm water surfaces.

Radio Frequency Compatibility of an RFID Tag on Glideslope Navigation Receivers

NASA Technical Reports Server (NTRS)

Nguyen, Truong X.; Mielnik, John J.

2008-01-01

A process is demonstrated to show compatibility between a radio frequency identification (RFID) tag and an aircraft glideslope (GS) radio r eceiver. The particular tag chosen was previously shown to have significant spurious emission levels that exceeded the emission limit in th e GS aeronautical band. The spurious emissions are emulated in the study by capturing the RFID fundamental transmission and playing back th e signal in the GS band. The signal capturing and playback are achiev ed with a vector signal generator and a spectrum analyzer that can output the in-phase and quadrature components (IQ). The simulated interf erence signal is combined with a GS signal before being injected into a GS receiver#s antenna port for interference threshold determination . Minimum desired propagation loss values to avoid interference are then computed and compared against actual propagation losses for severa l aircraft.

Biophysical mechanism of differential growth during gravitropism

NASA Technical Reports Server (NTRS)

Cosgrove, D.

1984-01-01

A research project is described the goal of which is to determine the mechanism of gravitropic curvature in plant stems at the biophysical and the cellular level. The reorientation of plant organs under the influence of gravity is due to differential growth of the upper and lower sides of the organ. The rate of plant cell enlargement is governed by four biophysical parameters: (1) the extensibility of the cell wall; (2) the minimum stress in the cell wall required for wall expansion (the "yield threshold'); (3) the osmotic pressure difference between the cell contents and the water source; and (4) the hydraulic conductivity of the pathway for water uptake. Gravitropic response must involve differential alteration of one or more of these four parameters on the two sides of the growing organ. Each of these factors will be examined to assess the role it plays in gravitropism.

Thermonuclear 46Cr(p ,γ )47Mn rate in type-I x-ray bursts

NASA Astrophysics Data System (ADS)

He, J. J.; Parikh, A.; Xu, Y.; Zhang, Y. H.; Zhou, X. H.; Xu, H. S.

2017-10-01

The thermonuclear rate of the 46Cr(p ,γ )47Mn reaction has been determined using a newly evaluated proton separation energy of Sp(47Mn) =380 ±30 keV and nuclear structure information from the mirror nucleus 47Ti. The astrophysical impact of this new rate and previously available rates has been investigated through one-zone postprocessing type-I x-ray burst calculations. The present 46Cr(p ,γ )47Mn rate leads to a mass fraction at A =46 that is 60 times larger than that obtained using a statistical model rate. The new results constrain the calculated maximum and minimum mass fractions at A =46 and A =48 to be within factors of 12 and 4, respectively. Experimental studies of the level structure of 47Mn near the proton threshold are required to improve these model predictions.

A pilot analytic study of a research-level, lower-cost human papillomavirus 16, 18, and 45 test.

PubMed

Yang, Hannah P; Walmer, David K; Merisier, Delson; Gage, Julia C; Bell, Laura; Rangwala, Sameera; Shrestha, Niwashin; Kobayashi, Lori; Eder, Paul S; Castle, Philip E

2011-09-01

The analytic performance of a low-cost, research-stage DNA test for the most carcinogenic human papillomavirus (HPV) genotypes (HPV16, HPV18, and HPV45) in aggregate was evaluated among carcinogenic HPV-positive women, which might be used to decide who needs immediate colposcopy in low-resource settings ("triage test"). We found that HPV16/18/45 test agreed well with two DNA tests, a GP5+/6+ genotyping assay (Kappa = 0.77) and a quantitative PCR assay (at a cutpoint of 5000 viral copies) (Kappa = 0.87). DNA sequencing on a subset of 16 HPV16/18/45 positive and 16 HPV16/18/45 negative verified the analytic specificity of the research test. It is concluded that the HPV16/18/45 assay is a promising triage test with a minimum detection of approximately 5000 viral copies, the clinically relevant threshold. Published by Elsevier B.V.

Behavioral and auditory evoked potential audiograms of a false killer whale (Pseudorca crassidens)

NASA Astrophysics Data System (ADS)

Yuen, Michelle M. L.; Nachtigall, Paul E.; Breese, Marlee; Supin, Alexander Ya.

2005-10-01

Behavioral and auditory evoked potential (AEP) audiograms of a false killer whale were measured using the same subject and experimental conditions. The objective was to compare and assess the correspondence of auditory thresholds collected by behavioral and electrophysiological techniques. Behavioral audiograms used 3-s pure-tone stimuli from 4 to 45 kHz, and were conducted with a go/no-go modified staircase procedure. AEP audiograms used 20-ms sinusoidally amplitude-modulated tone bursts from 4 to 45 kHz, and the electrophysiological responses were received through gold disc electrodes in rubber suction cups. The behavioral data were reliable and repeatable, with the region of best sensitivity between 16 and 24 kHz and peak sensitivity at 20 kHz. The AEP audiograms produced thresholds that were also consistent over time, with range of best sensitivity from 16 to 22.5 kHz and peak sensitivity at 22.5 kHz. Behavioral thresholds were always lower than AEP thresholds. However, AEP audiograms were completed in a shorter amount of time with minimum participation from the animal. These data indicated that behavioral and AEP techniques can be used successfully and interchangeably to measure cetacean hearing sensitivity.

Discontinuous non-equilibrium phase transition in a threshold Schloegl model for autocatalysis: Generic two-phase coexistence and metastability

DOE PAGES

Wang, Chi -Jen; Liu, Da -Jiang; Evans, James W.

2015-04-28

Threshold versions of Schloegl’s model on a lattice, which involve autocatalytic creation and spontaneous annihilation of particles, can provide a simple prototype for discontinuous non-equilibrium phase transitions. These models are equivalent to so-called threshold contact processes. A discontinuous transition between populated and vacuum states can occur selecting a threshold of N ≥ 2 for the minimum number, N, of neighboring particles enabling autocatalytic creation at an empty site. Fundamental open questions remain given the lack of a thermodynamic framework for analysis. For a square lattice with N = 2, we show that phase coexistence occurs not at a unique valuemore » but for a finite range of particle annihilation rate (the natural control parameter). This generic two-phase coexistence also persists when perturbing the model to allow spontaneous particle creation. Such behavior contrasts both the Gibbs phase rule for thermodynamic systems and also previous analysis for this model. We find metastability near the transition corresponding to a non-zero effective line tension, also contrasting previously suggested critical behavior. As a result, mean-field type analysis, extended to treat spatially heterogeneous states, further elucidates model behavior.« less

Discontinuous non-equilibrium phase transition in a threshold Schloegl model for autocatalysis: Generic two-phase coexistence and metastability

NASA Astrophysics Data System (ADS)

Wang, Chi-Jen; Liu, Da-Jiang; Evans, James W.

2015-04-01

Threshold versions of Schloegl's model on a lattice, which involve autocatalytic creation and spontaneous annihilation of particles, can provide a simple prototype for discontinuous non-equilibrium phase transitions. These models are equivalent to so-called threshold contact processes. A discontinuous transition between populated and vacuum states can occur selecting a threshold of N ≥ 2 for the minimum number, N, of neighboring particles enabling autocatalytic creation at an empty site. Fundamental open questions remain given the lack of a thermodynamic framework for analysis. For a square lattice with N = 2, we show that phase coexistence occurs not at a unique value but for a finite range of particle annihilation rate (the natural control parameter). This generic two-phase coexistence also persists when perturbing the model to allow spontaneous particle creation. Such behavior contrasts both the Gibbs phase rule for thermodynamic systems and also previous analysis for this model. We find metastability near the transition corresponding to a non-zero effective line tension, also contrasting previously suggested critical behavior. Mean-field type analysis, extended to treat spatially heterogeneous states, further elucidates model behavior.

Time to Exhaustion at the VO2max Velocity in Swimming: A Review

PubMed Central

Fernandes, Ricardo J.; Vilas-Boas, J. Paulo

2012-01-01

The aim of this study was to present a review on the time to exhaustion at the minimum swimming velocity corresponding to maximal oxygen consumption (TLim-vVO2max). This parameter is critical both for the aerobic power and the lactate tolerance bioenergetical training intensity zones, being fundamental to characterize it, and to point out its main determinants. The few number of studies conducted in this topic observed that swimmers were able to maintain an exercise intensity corresponding to maximal aerobic power during 215 to 260 s (elite swimmers), 230 to 260 s (high level swimmers) and 310 to 325 s (low level swimmers), and no differences between genders were reported. TLim-vVO2max main bioenergetic and functional determinants were swimming economy and VO2 slow component (direct relationship), and vVO2max, velocity at anaerobic threshold and blood lactate production (inverse relationship); when more homogeneous groups of swimmers were analysed, the inverse correlation value between TLim-vVO2max and vVO2max was not so evident. In general, TLim-vVO2max was not related to VO2max. TLim-vVO2max seems also to be influenced by stroking parameters, with a direct relationship to stroke length and stroke index, and an inverse correlation with stroke rate. Assessing TLim-vVO2max, together with the anaerobic threshold and the biomechanical general parameters, will allow a larger spectrum of testing protocols application, helping to build more objective and efficient training programs. PMID:23486651

Numerical exploration of Kaldorian interregional macrodynamics: stability and the trade threshold for business cycles under fixed exchange rates.

PubMed

Asada, Toichiro; Douskos, Christos; Markellos, Panagiotis

2011-01-01

The stability of equilibrium and the possibility of generation of business cycles in a discrete interregional Kaldorian macrodynamic model with fixed exchange rates are explored using numerical methods. One of the aims is to illustrate the feasibility and effectiveness of the numerical approach for dynamical systems of moderately high dimensionality and several parameters. The model considered is five-dimensional with four parameters, the speeds of adjustment of the goods markets and the degrees of economic interactions between the regions through trade and capital movement. Using a grid search method for the determination of the region of stability of equilibrium in two-dimensional parameter subspaces, and coefficient criteria for the flip bifurcation - and Hopf bifurcation - curve, we determine the stability region in several parameter ranges and identify Hopf bifurcation curves when they exist. It is found that interregional cycles emerge only for sufficient interregional trade. The relevant threshold is predicted by the model at 14 - 16 % of trade transactions. By contrast, no minimum level of capital mobility exists in a global sense as a requirement for the emergence of interregional cycles; the main conclusion being, therefore, that cycles may occur for very low levels of capital mobility if trade is sufficient. Examples of bifurcation and Lyapunov exponent diagrams illustrating the occurrence of cycles or period doubling, and examples of the development of the occurring cycles, are given. Both supercritical and subcritical bifurcations are found to occur, the latter type indicating coexistence of a point and a cyclical attractor.

How to determine an optimal threshold to classify real-time crash-prone traffic conditions?

PubMed

Yang, Kui; Yu, Rongjie; Wang, Xuesong; Quddus, Mohammed; Xue, Lifang

2018-08-01

One of the proactive approaches in reducing traffic crashes is to identify hazardous traffic conditions that may lead to a traffic crash, known as real-time crash prediction. Threshold selection is one of the essential steps of real-time crash prediction. And it provides the cut-off point for the posterior probability which is used to separate potential crash warnings against normal traffic conditions, after the outcome of the probability of a crash occurring given a specific traffic condition on the basis of crash risk evaluation models. There is however a dearth of research that focuses on how to effectively determine an optimal threshold. And only when discussing the predictive performance of the models, a few studies utilized subjective methods to choose the threshold. The subjective methods cannot automatically identify the optimal thresholds in different traffic and weather conditions in real application. Thus, a theoretical method to select the threshold value is necessary for the sake of avoiding subjective judgments. The purpose of this study is to provide a theoretical method for automatically identifying the optimal threshold. Considering the random effects of variable factors across all roadway segments, the mixed logit model was utilized to develop the crash risk evaluation model and further evaluate the crash risk. Cross-entropy, between-class variance and other theories were employed and investigated to empirically identify the optimal threshold. And K-fold cross-validation was used to validate the performance of proposed threshold selection methods with the help of several evaluation criteria. The results indicate that (i) the mixed logit model can obtain a good performance; (ii) the classification performance of the threshold selected by the minimum cross-entropy method outperforms the other methods according to the criteria. This method can be well-behaved to automatically identify thresholds in crash prediction, by minimizing the cross entropy between the original dataset with continuous probability of a crash occurring and the binarized dataset after using the thresholds to separate potential crash warnings against normal traffic conditions. Copyright © 2018 Elsevier Ltd. All rights reserved.

Salicylate-induced changes in auditory thresholds of adolescent and adult rats.

PubMed

Brennan, J F; Brown, C A; Jastreboff, P J

1996-01-01

Shifts in auditory intensity thresholds after salicylate administration were examined in postweanling and adult pigmented rats at frequencies ranging from 1 to 35 kHz. A total of 132 subjects from both age levels were tested under two-way active avoidance or one-way active avoidance paradigms. Estimated thresholds were inferred from behavioral responses to presentations of descending and ascending series of intensities for each test frequency value. Reliable threshold estimates were found under both avoidance conditioning methods, and compared to controls, subjects at both age levels showed threshold shifts at selective higher frequency values after salicylate injection, and the extent of shifts was related to salicylate dose level.

Affordability of residential water tariffs: alternative measurement and explanatory factors in southern Spain.

PubMed

García-Valiñas, Maria A; Martínez-Espiñeira, Roberto; González-Gómez, Francisco

2010-12-01

Using information on a basic or "lifeline" level of domestic water use obtained from a water demand function based on a Stone-Geary utility function, a minimum water threshold of 128 m(3) per household per year was estimated in a sample of municipalities in Southern Spain. As a second objective, water affordability indexes were then calculated that relate the cost of such lifeline to average municipal income levels. The analysis of the factors behind the differences in that ratio across Andalusian municipalities shows that the relative cost of purchasing the lifeline appears inversely related to average income levels, revealing an element of regressivity in the component of water tariffs affecting the least superfluous part of the household's consumption. The main policy recommendation would involve redesigning water tariffs in order to improve access for lower income households to an amount of water sufficient to cover their basic needs. The proposed methodology could be applied to other geographical areas, both from developed and from developing countries, in order to analyze the degree of progressivity of the water tariffs currently in effect and in order to guide the design of more equitable regulatory policies. Copyright © 2010 Elsevier Ltd. All rights reserved.

Three-level sampler having automated thresholds

NASA Technical Reports Server (NTRS)

Jurgens, R. F.

1976-01-01

A three-level sampler is described that has its thresholds controlled automatically so as to track changes in the statistics of the random process being sampled. In particular, the mean value is removed and the ratio of the standard deviation of the random process to the threshold is maintained constant. The system is configured in such a manner that slow drifts in the level comparators and digital-to-analog converters are also removed. The ratio of the standard deviation to threshold level may be chosen within the constraints of the ratios of two integers N and M. These may be chosen to minimize the quantizing noise of the sampled process.

The Effects of Compensatory Auditory Stimulation and High-Definition Transcranial Direct Current Stimulation (HD-tDCS) on Tinnitus Perception - A Randomized Pilot Study.

PubMed

Henin, Simon; Fein, Dovid; Smouha, Eric; Parra, Lucas C

2016-01-01

Tinnitus correlates with elevated hearing thresholds and reduced cochlear compression. We hypothesized that reduced peripheral input leads to elevated neuronal gain resulting in the perception of a phantom sound. The purpose of this pilot study was to test whether compensating for this peripheral deficit could reduce the tinnitus percept acutely using customized auditory stimulation. To further enhance the effects of auditory stimulation, this intervention was paired with high-definition transcranial direct current stimulation (HD-tDCS). A randomized sham-controlled, single blind study was conducted in a clinical setting on adult participants with chronic tinnitus (n = 14). Compensatory auditory stimulation (CAS) and HD-tDCS were administered either individually or in combination in order to access the effects of both interventions on tinnitus perception. CAS consisted of sound exposure typical to daily living (20-minute sound-track of a TV show), which was adapted with compressive gain to compensate for deficits in each subject's individual audiograms. Minimum masking levels and the visual analog scale were used to assess the strength of the tinnitus percept immediately before and after the treatment intervention. CAS reduced minimum masking levels, and visual analog scale trended towards improvement. Effects of HD-tDCS could not be resolved with the current sample size. The results of this pilot study suggest that providing tailored auditory stimulation with frequency-specific gain and compression may alleviate tinnitus in a clinical population. Further experimentation with longer interventions is warranted in order to optimize effect sizes.

A new and efficient theoretical model to analyze chirped grating distributed feedback lasers

NASA Astrophysics Data System (ADS)

Arif, Muhammad

Threshold conditions of a distributed feedback (DFB) laser with a linearly chirped grating are investigated using a new and efficient method. DFB laser with chirped grating is found to have significant effects on the lasing characteristics. The coupled wave equations for these lasers are derived and solved using a power series method to obtain the threshold condition. A Newton- Raphson routine is used to solve the threshold conditions numerically to obtain threshold gain and lasing wavelengths. To prove the validity of this model, it is applied to both conventional index-coupled and complex- coupled DFB lasers. The threshold gain margins are calculated as functions of the ratio of the gain coupling to index coupling (|κg|/|κ n|), and the phase difference between the index and gain gratings. It was found that for coupling coefficient |κ|l < 0.9, the laser shows a mode degeneracy at particular values of the ratio |κ g|/|κn|, for cleaved facets. We found that at phase differences π/2 and 3π/2, between the gain and index grating, for an AR-coated complex-coupled laser, the laser becomes multimode and a different mode starts to lase. We also studied the effect of the facet reflectivity (both magnitude and phase) on the gain margin of a complex- coupled DFB laser. Although, the gain margin varies slowly with the magnitude of the facet reflectivity, it shows large variations as a function of the phase. Spatial hole burning was found to be minimum at phase difference nπ, n = 0, 1, ... and maximum at phase differences π/2 and 3π/2. The single mode gain margin of an index-coupled linearly chirped CG-DFB is calculated for different chirping factors and coupling constants. We found that there is clearly an optimum chirping for which the single mode gain margin is maximum. The gain margins were calculated also for different positions of the cavity center. The effect of the facet reflectivities and their phases on the gain margin was investigated. We found the gain margin is maximum and the Spatial Hole Burning (SHB) is minimum for the cavity center at the middle of the laser cavity. Effect of chirping on the threshold gain, gain margin and spatial hole burning (SHB) for different parameters, such as the coupling coefficients, facet reflectivities, etc., of these lasers are studied. Single mode yield of these lasers are calculated and compared with that of a uniform grating DFB laser.

Application of a Fuzzy Verification Technique for Assessment of the Weather Running Estimate-Nowcast (WRE-N) Model

DTIC Science & Technology

2016-10-01

comes when considering numerous scores and statistics during a preliminary evaluation of the applicability of the fuzzy- verification minimum coverage...The selection of thresholds with which to generate categorical-verification scores and statistics from the application of both traditional and...of statistically significant numbers of cases; the latter presents a challenge of limited application for assessment of the forecast models’ ability

Community benefit in exchange for non-profit hospital tax exemption: current trends and future outlook.

PubMed

Singh, Simone Rauscher

2013-01-01

Assessing the adequacy of the community benefits that not-for-profit hospitals provide in exchange for tax exemption remains a challenge. While recent changes to Internal Revenue Service (IRS) reporting requirements have improved transparency, the lack of clearly defined charitable expectations has resulted in critical scrutiny of not-for-profit hospitals' community benefits and numerous challenges to their tax exempt status. Using data from the revised IRS Form 990 Schedule H for 2009, this article documents the wide range of community benefit activities that not-for-profit hospitals in California engage in and compares them to a set of minimum spending thresholds. The findings show that when community benefit was defined narrowly in terms of charity care, very few hospitals would have met any of the minimum spending thresholds. When community benefit was defined as in the revised IRS Form 990 Schedule H, however, a majority of hospitals in California would have been considered charitable. Whether focusing on expenditures is the most appropriate way to assess the adequacy of a hospital's community benefits remains an open question. To that end, this article concludes by outlining a more comprehensive evaluation approach that builds on recent changes to non-profit hospital tax exemption implemented by the Affordable Care Act.

Solar cooling in Madrid: Available solar energy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Izquierdo, M.; Hernandez, F.; Martin, E.

1994-11-01

This paper analyzes the behaviour of an absorption chiller lithium bromide installation fed by a field of flat-plate solar collectors and condensed by swimming pool water. A method of calculation in a variable regime is developed in terms of the obtained experimental results. Starting from the meteorological variables of a clear summer day and from the project data (collector normalization curve, collector and installation mass), the minimum solar radiation level necessary to initiate the process, I[sub min], and the instantaneous available solar energy, Q[sub u] + W[sub 1] is determined. The solar radiation threshold, I[sub min], necessary to obtain themore » process temperature, t[sub ave], in each instant, is obtained by adding to the corrected Klein radiation threshold, I[sub k,c], the heat capacity effects of the collector, HCE[sub CO], and of the installation, HCE[sub ins], as well as the losses of heat of the pipes to the surroundings, Q[sub 1]. The instantaneous available solar energy, available useful heat, in addition to the wind collector losses to the surroundings, Q[sub u] + W[sub 1], is the difference, in each instant, between the radiation, I[sub g1T], and the radiation threshold, I[sub min].The integration during the day of the instantaneous available solar energy allows us to calculate the daily available function, H[sub T]. The value of H[sub T], measured in the swimming-pool water condensation installation reached 6.92 MJ/(m[sup 2] day ). The calculated values of H[sub T] for a conventional installation condensed by tower water, or air, have been 6.35 and 0.56 MJ/(m[sup 2] day). respectively.« less

Methods to achieve high interrater reliability in data collection from primary care medical records.

PubMed

Liddy, Clare; Wiens, Miriam; Hogg, William

2011-01-01

We assessed interrater reliability (IRR) of chart abstractors within a randomized trial of cardiovascular care in primary care. We report our findings, and outline issues and provide recommendations related to determining sample size, frequency of verification, and minimum thresholds for 2 measures of IRR: the κ statistic and percent agreement. We designed a data quality monitoring procedure having 4 parts: use of standardized protocols and forms, extensive training, continuous monitoring of IRR, and a quality improvement feedback mechanism. Four abstractors checked a 5% sample of charts at 3 time points for a predefined set of indicators of the quality of care. We set our quality threshold for IRR at a κ of 0.75, a percent agreement of 95%, or both. Abstractors reabstracted a sample of charts in 16 of 27 primary care practices, checking a total of 132 charts with 38 indicators per chart. The overall κ across all items was 0.91 (95% confidence interval, 0.90-0.92) and the overall percent agreement was 94.3%, signifying excellent agreement between abstractors. We gave feedback to the abstractors to highlight items that had a κ of less than 0.70 or a percent agreement less than 95%. No practice had to have its charts abstracted again because of poor quality. A 5% sampling of charts for quality control using IRR analysis yielded κ and agreement levels that met or exceeded our quality thresholds. Using 3 time points during the chart audit phase allows for early quality control as well as ongoing quality monitoring. Our results can be used as a guide and benchmark for other medical chart review studies in primary care.

Antihypertensive drugs: a perspective on pharmaceutical price erosion and its impact on cost-effectiveness.

PubMed

Refoios Camejo, Rodrigo; McGrath, Clare; Herings, Ron; Meerding, Willem-Jan; Rutten, Frans

2012-01-01

When comparators' prices decrease due to market competition and loss of exclusivity, the incremental clinical effectiveness required for a new technology to be cost-effective is expected to increase; and/or the minimum price at which it will be funded will tend to decrease. This may be, however, either unattainable physiologically or financially unviable for drug development. The objective of this study is to provide an empirical basis for this discussion by estimating the potential for price decreases to impact on the cost-effectiveness of new therapies in hypertension. Cost-effectiveness at launch was estimated for all antihypertensive drugs launched between 1998 and 2008 in the United Kingdom using hypothetical degrees of incremental clinical effectiveness within the methodologic framework applied by the UK National Institute for Health and Clinical Excellence. Incremental cost-effectiveness ratios were computed and compared with funding thresholds. In addition, the levels of incremental clinical effectiveness required to achieve specific cost-effectiveness thresholds at given prices were estimated. Significant price decreases were observed for existing drugs. This was shown to markedly affect cost-effectiveness of technologies entering the market. The required incremental clinical effectiveness was in many cases greater than physiologically possible so, as a consequence, a number of products might not be available today if current methods of economic appraisal had been applied. We conclude that the definition of cost-effectiveness thresholds is fundamental in promoting efficient innovation. Our findings demonstrate that comparator price attrition has the potential to put pressure in the pharmaceutical research model and presents a challenge to new therapies being accepted for funding. Copyright © 2012 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

[Correlation analysis of hearing level and soft palate movement after palatoplasty].

PubMed

Lou, Qun; Ma, Xiaoran; Ma, Lian; Luo, Yi; Zhu, Hongping; Zhou, Zhibo

2015-10-01

To explore the relationship between hearing level and soft palate movement after palatoplasty and to verify the importance of recovery of soft palate movement function for improving the middle ear function as well as reducing the hearing loss. A total of 64 non-syndromic cleft palate patients were selected and the lateral cephalometric radiographs were taken. The patients hearing level was evaluated by the pure tone hearing threshold examination. This study also analyzed the correlation between hearing threshold of the patients after palatoplasty and the soft palate elevation angle and velopharyngeal rate respectively. Kendall correlation analysis revealed that the correlation coefficient between hearing threshold and the soft palate elevation angle after palatoplasty was -0.339 (r = -0.339, P < 0.01).The correlation showed a negative correlation. The hearing threshold decreased as the soft palate elevation angle increased. After palatoplasty, the correlation coefficient between the hearing threshold and the rate of velopharyngeal closure was -0.277 (r = -0.277, P < 0.01). The correlation showed a negative correlation. While, The hearing threshold decreased with the increase of velopharyngeal closure rate. The hearing threshold was correlated with soft palate elevation angle and velpharyngeal closure rate. The movement of soft palate and velopharyngeal closure function after palatoplasty both have impact on patient hearing level. In terms of the influence level, the movement of soft palate has a higher level of impact on patient hearing level than velopharygeal closure function.

Drought survival is a threshold function of habitat size and population density in a fish metapopulation.

PubMed

White, Richard S A; McHugh, Peter A; McIntosh, Angus R

2016-10-01

Because smaller habitats dry more frequently and severely during droughts, habitat size is likely a key driver of survival in populations during climate change and associated increased extreme drought frequency. Here, we show that survival in populations during droughts is a threshold function of habitat size driven by an interaction with population density in metapopulations of the forest pool dwelling fish, Neochanna apoda. A mark-recapture study involving 830 N. apoda individuals during a one-in-seventy-year extreme drought revealed that survival during droughts was high for populations occupying pools deeper than 139 mm, but declined steeply in shallower pools. This threshold was caused by an interaction between increasing population density and drought magnitude associated with decreasing habitat size, which acted synergistically to increase physiological stress and mortality. This confirmed two long-held hypotheses, firstly concerning the interactive role of population density and physiological stress, herein driven by habitat size, and secondly, the occurrence of drought survival thresholds. Our results demonstrate how survival in populations during droughts will depend strongly on habitat size and highlight that minimum habitat size thresholds will likely be required to maximize survival as the frequency and intensity of droughts are projected to increase as a result of global climate change. © 2016 John Wiley & Sons Ltd.

The Threshold Level--For Schools?

ERIC Educational Resources Information Center

Lauerbach, Gerda

1979-01-01

Comments on the document "Threshold Level for Modern Language Learning Schools" (J. A. Van Ek, Strasbourg, 1976) and its appropriateness as a description of learning goals for the first years of foreign language teaching. Criticizes particularly the "reduced learning" concept, on which the threshold projects are based. (IFS/WGA)

MEMS-based flexible reflective analog modulators (FRAM) for projection displays: a technology review and scale-down study

NASA Astrophysics Data System (ADS)

Picard, Francis; Ilias, Samir; Asselin, Daniel; Boucher, Marc-André; Duchesne, François; Jacob, Michel; Larouche, Carl; Vachon, Carl; Niall, Keith K.; Jerominek, Hubert

2011-02-01

A MEMS based technology for projection display is reviewed. This technology relies on mechanically flexible and reflective microbridges made of aluminum alloy. A linear array of such micromirrors is combined with illumination and Schlieren optics to produce a pixels line. Each microbridge in the array is individually controlled using electrostatic actuation to adjust the pixels intensities. Results of the simulation, fabrication and characterization of these microdevices are presented. Activation voltages below 250 V with response times below 10 μs were obtained for 25 μm × 25 μm micromirrors. With appropriate actuation voltage waveforms, response times of 5 μs and less are achievable. A damage threshold of the mirrors above 8 kW/cm2 has been evaluated. Development of the technology has produced projector engines demonstrating this light modulation principle. The most recent of these engines is DVI compatible and displays VGA video streams at 60 Hz. Recently applications have emerged that impose more stringent requirements on the dimensions of the MEMS array and associated optical system. This triggered a scale down study to evaluate the minimum micromirror size achievable, the impact of this reduced size on the damage threshold and the achievable minimum size of the associated optical system. Preliminary results of this scale down study are reported. FRAM with active surface as small as 5 μm × 5 μm have been investigated. Simulations have shown that such micromirrors could be activated with 107 V to achieve f-number of 1.25. The damage threshold has been estimated for various FRAM sizes. Finally, design of a conceptual miniaturized projector based on 1000×1 array of 5 μm × 5 μm micromirrors is presented. The volume of this projector concept is about 12 cm3.

Exploiting the potential of free software to evaluate root canal biomechanical preparation outcomes through micro-CT images.

PubMed

Neves, A A; Silva, E J; Roter, J M; Belladona, F G; Alves, H D; Lopes, R T; Paciornik, S; De-Deus, G A

2015-11-01

To propose an automated image processing routine based on free software to quantify root canal preparation outcomes in pairs of sound and instrumented roots after micro-CT scanning procedures. Seven mesial roots of human mandibular molars with different canal configuration systems were studied: (i) Vertucci's type 1, (ii) Vertucci's type 2, (iii) two individual canals, (iv) Vertucci's type 6, canals (v) with and (vi) without debris, and (vii) canal with visible pulp calcification. All teeth were instrumented with the BioRaCe system and scanned in a Skyscan 1173 micro-CT before and after canal preparation. After reconstruction, the instrumented stack of images (IS) was registered against the preoperative sound stack of images (SS). Image processing included contrast equalization and noise filtering. Sound canal volumes were obtained by a minimum threshold. For the IS, a fixed conservative threshold was chosen as the best compromise between instrumented canal and dentine whilst avoiding debris, resulting in instrumented canal plus empty spaces. Arithmetic and logical operations between sound and instrumented stacks were used to identify debris. Noninstrumented dentine was calculated using a minimum threshold in the IS and subtracting from the SS and total debris. Removed dentine volume was obtained by subtracting SS from IS. Quantitative data on total debris present in the root canal space after instrumentation, noninstrumented areas and removed dentine volume were obtained for each test case, as well as three-dimensional volume renderings. After standardization of acquisition, reconstruction and image processing micro-CT images, a quantitative approach for calculation of root canal biomechanical outcomes was achieved using free software. © 2014 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Effects of Tongue Force Training on Orolingual Motor Cortical Representation

PubMed Central

Guggenmos, David J.; Barbay, Scott; Bethel-Brown, Crystal; Nudo, Randolph J.; Stanford, John A.

2009-01-01

Previous research has demonstrated that training rats in a skilled reaching condition will induce task-related changes in the caudal forelimb area of motor cortex. The purpose of the present study was to determine whether task-specific changes can be induced within the orofacial area of the motor cortex in rats. Specifically, we compared changes of the orofacial motor cortical representation in lick-trained rats to age-matched controls. For one month, six water-restricted Sprague-Dawley rats were trained to lick an isometric force-sensing disc at increasing forces for water reinforcement. The rats were trained daily for six minutes starting with forces of 1g, and increasing over the course of the month to 10, 15, 20, 25 and finally 30 g. One to three days following the last training session, the animals were subjected to a neurophysiological motor mapping procedure in which motor representations corresponding to the orofacial and adjacent areas were defined using intracortical microstimulation (ICMS) techniques. We found no statistical difference in the topographical representation of the control (mean = 2.03 mm2) vs. trained (1.87 mm2) rats. This result indicates that force training alone is insufficient to drive changes in the size of the cortical representation. We also recorded the minimum current threshold required to elicit a motor response at each site of microstimulation. We found that the lick-trained rats had a significantly lower average minimum threshold (29.1 ± 1.0 μA) for evoking movements related to the task compared to control rats (34.6 ± 1.1 μA). These results indicate that while tongue force training alone does not produce lasting changes in the size of the orofacial cortical motor representation, tongue force training decreases the current thresholds necessary for eliciting an ICMS-evoked motor response. PMID:19428638

Viewing Events in the Center-of-Mass System

NASA Astrophysics Data System (ADS)

Ruby, Lawrence

2010-02-01

In elementary physics, collisions are usually studied by employing the conservation of momentum, and sometimes also the conservation of kinetic energy. However, in nuclear reactions, changes of mass that complicate the situation often occur. To illustrate the latter, we shall cite two examples of endoergic nuclear reactions, i.e., those for which energy must be supplied to make the reaction proceed. A typical situation is given by the equation A + B → C + D + Q, (1) where particles A, B, C, and D are expressed in terms of the energy-equivalent of the particle masses, according to the Einstein relation E = mc2, and where Q is a negative energy quantity, corresponding to the excess of mass of (C + D) over that of (A + B). Equation (1) is just an alternate statement of the conservation of total energy. Typically, in the lab system (L), energy is supplied as kinetic energy "T" of particle A, and particle B is at rest. Thus, to conserve momentum, particles C and D must compensate for the momentum corresponding to T. Often, it is desirable to know the minimum value of T that will conserve both energy and momentum, i.e., the threshold value of T, known as Tth, that will just allow the reaction to proceed. At threshold, the particles C and D will have their minimum possible kinetic energies. In the center-of-mass system of coordinates (Z) in which the input momentum is zero, at threshold, the products C and D are each stationary, and this requirement will allow us to calculate the corresponding Tth in the lab system (L). The Z system is often termed the "center-of-mass" system, but it is more properly termed the "zero-momentum" system.

How Low Can You Go? Determining a Size Threshold for Implantation of a New Acoustic Transmitter in Age-0 White Sturgeon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ashton, Neil K.; Liss, Stephanie A.; Walker, Ricardo W.

Telemetry studies are often used to investigate sturgeon habitat use and movement patterns; however, existing acoustic transmitters are generally too large to implant into age-0 sturgeon without harming the fish. Recent development of a miniaturized acoustic transmitter (cylindrical, 0.7 g in air, 24.2 mm long, 5.0 mm diameter) with up to 365 d battery life has the potential to advance our understanding of age-0 sturgeon ecology in rivers and lakes. Prior to use in field studies, it is essential to conduct experiments evaluating potential adverse transmitter effects on fish. We tested transmitter retention, fish survival, and growth of a broadmore » size range of age-0 white sturgeon (Acipenser transmontanus; 158–277 mm fork length; 26–126 g; 0.6–2.6% transmitter burden) in an 84 d laboratory study, with an ultimate goal of determining a minimum size threshold of sturgeon that can be implanted with this acoustic transmitter. At 84 d post-implantation, transmitter retention and fish survival were 100%. Specific growth rates were reduced at 7 and 14 d post-implantation, resulting in minimum fork length thresholds of 250 and 171 mm, respectively. Juveniles implanted with transmitters regained their growth potential by 28 d post-implantation and no size differences were detected in comparisons with unmarked control fish. This study demonstrates the ability to implant small age-0 sturgeon with high transmitter retention and fish survival, and only minor growth effects. Use of new miniaturized acoustic transmitters may give researchers a means to address questions about young-of-the-year fish recruitment, ecological patterns, and potentially advance conservation management of sturgeon populations.« less

Analysis of the PLL phase error in presence of simulated ionospheric scintillation events

NASA Astrophysics Data System (ADS)

Forte, B.

2012-01-01

The functioning of standard phase locked loops (PLL), including those used to track radio signals from Global Navigation Satellite Systems (GNSS), is based on a linear approximation which holds in presence of small phase errors. Such an approximation represents a reasonable assumption in most of the propagation channels. However, in presence of a fading channel the phase error may become large, making the linear approximation no longer valid. The PLL is then expected to operate in a non-linear regime. As PLLs are generally designed and expected to operate in their linear regime, whenever the non-linear regime comes into play, they will experience a serious limitation in their capability to track the corresponding signals. The phase error and the performance of a typical PLL embedded into a commercial multiconstellation GNSS receiver were analyzed in presence of simulated ionospheric scintillation. Large phase errors occurred during scintillation-induced signal fluctuations although cycle slips only occurred during the signal re-acquisition after a loss of lock. Losses of lock occurred whenever the signal faded below the minimumC/N0threshold allowed for tracking. The simulations were performed for different signals (GPS L1C/A, GPS L2C, GPS L5 and Galileo L1). L5 and L2C proved to be weaker than L1. It appeared evident that the conditions driving the PLL phase error in the specific case of GPS receivers in presence of scintillation-induced signal perturbations need to be evaluated in terms of the combination of the minimumC/N0 tracking threshold, lock detector thresholds, possible cycle slips in the tracking PLL and accuracy of the observables (i.e. the error propagation onto the observables stage).

75 FR 44841 - Hazardous Materials: Special Permits and Approvals-Minimum Level of Fitness Determinations...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-29

... Materials: Special Permits and Approvals--Minimum Level of Fitness Determinations; Public Meeting AGENCY... Special Permit and Approval applicant fitness determinations. PHMSA will hold a public meeting on August... minimum level of fitness. DATES: Public Meeting: August 19, 2010; starting at 9:30 a.m. and ending by 3:30...

Climate variability in Andalusia (southern Spain) during the period 1701-1850 AD from documentary sources: evaluation and comparison with climate model simulations

NASA Astrophysics Data System (ADS)

Rodrigo, F. S.; Gómez-Navarro, J. J.; Montávez Gómez, J. P.

2011-07-01

In this work, a reconstruction of climatic conditions in Andalusia (southern Iberia Peninsula) during the period 1701-1850, as well as an evaluation of its associated uncertainties, is presented. This period is interesting because it is characterized by a minimum in the solar irradiance (Dalton Minimum, around 1800), as well as intense volcanic activity (for instance, the eruption of the Tambora in 1815), when the increasing atmospheric CO2 concentrations were of minor importance. The reconstruction is based on the analysis of a wide variety of documentary data. The reconstruction methodology is based on accounting the number of extreme events in past, and inferring mean value and standard deviation using the assumption of normal distribution for the seasonal means of climate variables. This reconstruction methodology is tested within the pseudoreality of a high-resolution paleoclimate simulation performed with the regional climate model MM5 coupled to the global model ECHO-G. Results show that the reconstructions are influenced by the reference period chosen and the threshold values used to define extreme values. This creates uncertainties which are assesed within the context of the climate simulation. An ensemble of reconstructions was obtained using two different reference periods and two pairs of percentiles as threshold values. Results correspond to winter temperature, and winter, spring, and autumn rainfall, and they are compared with simulations of the climate model for the considered period. The comparison of the distribution functions corresponding to 1790-1820 and 1960-1990 periods indicates that during the Dalton Minimum the frequency of dry and warm (wet and cold) winters was lesser (higher) than during the reference period. In spring and autumn it was detected an increase (decrease) in the frequency of wet (dry) seasons. Future research challenges are outlined.

The Short-Term Effect of Ambient Temperature on Mortality in Wuhan, China: A Time-Series Study Using a Distributed Lag Non-Linear Model

PubMed Central

Zhang, Yunquan; Li, Cunlu; Feng, Renjie; Zhu, Yaohui; Wu, Kai; Tan, Xiaodong; Ma, Lu

2016-01-01

Less evidence concerning the association between ambient temperature and mortality is available in developing countries/regions, especially inland areas of China, and few previous studies have compared the predictive ability of different temperature indictors (minimum, mean, and maximum temperature) on mortality. We assessed the effects of temperature on daily mortality from 2003 to 2010 in Jiang’an District of Wuhan, the largest city in central China. Quasi-Poisson generalized linear models combined with both non-threshold and double-threshold distributed lag non-linear models (DLNM) were used to examine the associations between different temperature indictors and cause-specific mortality. We found a U-shaped relationship between temperature and mortality in Wuhan. Double-threshold DLNM with mean temperature performed best in predicting temperature-mortality relationship. Cold effect was delayed, whereas hot effect was acute, both of which lasted for several days. For cold effects over lag 0–21 days, a 1 °C decrease in mean temperature below the cold thresholds was associated with a 2.39% (95% CI: 1.71, 3.08) increase in non-accidental mortality, 3.65% (95% CI: 2.62, 4.69) increase in cardiovascular mortality, 3.87% (95% CI: 1.57, 6.22) increase in respiratory mortality, 3.13% (95% CI: 1.88, 4.38) increase in stroke mortality, and 21.57% (95% CI: 12.59, 31.26) increase in ischemic heart disease (IHD) mortality. For hot effects over lag 0–7 days, a 1 °C increase in mean temperature above the hot thresholds was associated with a 25.18% (95% CI: 18.74, 31.96) increase in non-accidental mortality, 34.10% (95% CI: 25.63, 43.16) increase in cardiovascular mortality, 24.27% (95% CI: 7.55, 43.59) increase in respiratory mortality, 59.1% (95% CI: 41.81, 78.5) increase in stroke mortality, and 17.00% (95% CI: 7.91, 26.87) increase in IHD mortality. This study suggested that both low and high temperature were associated with increased mortality in Wuhan, and that mean temperature had better predictive ability than minimum and maximum temperature in the association between temperature and mortality. PMID:27438847

Chromatic Perceptual Learning but No Category Effects without Linguistic Input.

PubMed

Grandison, Alexandra; Sowden, Paul T; Drivonikou, Vicky G; Notman, Leslie A; Alexander, Iona; Davies, Ian R L

2016-01-01

Perceptual learning involves an improvement in perceptual judgment with practice, which is often specific to stimulus or task factors. Perceptual learning has been shown on a range of visual tasks but very little research has explored chromatic perceptual learning. Here, we use two low level perceptual threshold tasks and a supra-threshold target detection task to assess chromatic perceptual learning and category effects. Experiment 1 investigates whether chromatic thresholds reduce as a result of training and at what level of analysis learning effects occur. Experiment 2 explores the effect of category training on chromatic thresholds, whether training of this nature is category specific and whether it can induce categorical responding. Experiment 3 investigates the effect of category training on a higher level, lateralized target detection task, previously found to be sensitive to category effects. The findings indicate that performance on a perceptual threshold task improves following training but improvements do not transfer across retinal location or hue. Therefore, chromatic perceptual learning is category specific and can occur at relatively early stages of visual analysis. Additionally, category training does not induce category effects on a low level perceptual threshold task, as indicated by comparable discrimination thresholds at the newly learned hue boundary and adjacent test points. However, category training does induce emerging category effects on a supra-threshold target detection task. Whilst chromatic perceptual learning is possible, learnt category effects appear to be a product of left hemisphere processing, and may require the input of higher level linguistic coding processes in order to manifest.

State-level minimum wage and heart disease death rates in the United States, 1980-2015: A novel application of marginal structural modeling.

PubMed

Van Dyke, Miriam E; Komro, Kelli A; Shah, Monica P; Livingston, Melvin D; Kramer, Michael R

2018-07-01

Despite substantial declines since the 1960's, heart disease remains the leading cause of death in the United States (US) and geographic disparities in heart disease mortality have grown. State-level socioeconomic factors might be important contributors to geographic differences in heart disease mortality. This study examined the association between state-level minimum wage increases above the federal minimum wage and heart disease death rates from 1980 to 2015 among 'working age' individuals aged 35-64 years in the US. Annual, inflation-adjusted state and federal minimum wage data were extracted from legal databases and annual state-level heart disease death rates were obtained from CDC Wonder. Although most minimum wage and health studies to date use conventional regression models, we employed marginal structural models to account for possible time-varying confounding. Quasi-experimental, marginal structural models accounting for state, year, and state × year fixed effects estimated the association between increases in the state-level minimum wage above the federal minimum wage and heart disease death rates. In models of 'working age' adults (35-64 years old), a $1 increase in the state-level minimum wage above the federal minimum wage was on average associated with ~6 fewer heart disease deaths per 100,000 (95% CI: -10.4, -1.99), or a state-level heart disease death rate that was 3.5% lower per year. In contrast, for older adults (65+ years old) a $1 increase was on average associated with a 1.1% lower state-level heart disease death rate per year (b = -28.9 per 100,000, 95% CI: -71.1, 13.3). State-level economic policies are important targets for population health research. Copyright © 2018 Elsevier Inc. All rights reserved.

A threshold-based cloud mask for the high-resolution visible channel of Meteosat Second Generation SEVIRI

NASA Astrophysics Data System (ADS)

Bley, S.; Deneke, H.

2013-10-01

A threshold-based cloud mask for the high-resolution visible (HRV) channel (1 × 1 km2) of the Meteosat SEVIRI (Spinning Enhanced Visible and Infrared Imager) instrument is introduced and evaluated. It is based on operational EUMETSAT cloud mask for the low-resolution channels of SEVIRI (3 × 3 km2), which is used for the selection of suitable thresholds to ensure consistency with its results. The aim of using the HRV channel is to resolve small-scale cloud structures that cannot be detected by the low-resolution channels. We find that it is of advantage to apply thresholds relative to clear-sky reflectance composites, and to adapt the threshold regionally. Furthermore, the accuracy of the different spectral channels for thresholding and the suitability of the HRV channel are investigated for cloud detection. The case studies show different situations to demonstrate the behavior for various surface and cloud conditions. Overall, between 4 and 24% of cloudy low-resolution SEVIRI pixels are found to contain broken clouds in our test data set depending on considered region. Most of these broken pixels are classified as cloudy by EUMETSAT's cloud mask, which will likely result in an overestimate if the mask is used as an estimate of cloud fraction. The HRV cloud mask aims for small-scale convective sub-pixel clouds that are missed by the EUMETSAT cloud mask. The major limit of the HRV cloud mask is the minimum cloud optical thickness (COT) that can be detected. This threshold COT was found to be about 0.8 over ocean and 2 over land and is highly related to the albedo of the underlying surface.

Detection Thresholds of Falling Snow From Satellite-Borne Active and Passive Sensors

NASA Technical Reports Server (NTRS)

Skofronick-Jackson, Gail M.; Johnson, Benjamin T.; Munchak, S. Joseph

2013-01-01

There is an increased interest in detecting and estimating the amount of falling snow reaching the Earths surface in order to fully capture the global atmospheric water cycle. An initial step toward global spaceborne falling snow algorithms for current and future missions includes determining the thresholds of detection for various active and passive sensor channel configurations and falling snow events over land surfaces and lakes. In this paper, cloud resolving model simulations of lake effect and synoptic snow events were used to determine the minimum amount of snow (threshold) that could be detected by the following instruments: the W-band radar of CloudSat, Global Precipitation Measurement (GPM) Dual-Frequency Precipitation Radar (DPR)Ku- and Ka-bands, and the GPM Microwave Imager. Eleven different nonspherical snowflake shapes were used in the analysis. Notable results include the following: 1) The W-band radar has detection thresholds more than an order of magnitude lower than the future GPM radars; 2) the cloud structure macrophysics influences the thresholds of detection for passive channels (e.g., snow events with larger ice water paths and thicker clouds are easier to detect); 3) the snowflake microphysics (mainly shape and density)plays a large role in the detection threshold for active and passive instruments; 4) with reasonable assumptions, the passive 166-GHz channel has detection threshold values comparable to those of the GPM DPR Ku- and Ka-band radars with approximately 0.05 g *m(exp -3) detected at the surface, or an approximately 0.5-1.0-mm * h(exp -1) melted snow rate. This paper provides information on the light snowfall events missed by the sensors and not captured in global estimates.

Foveal threshold and photoreceptor integrity for prediction of visual acuity after intravitreal aflibercept on age-related macular degeneration.

PubMed

Sakai, Tsutomu; Okude, Sachiyo; Tsuneoka, Hiroshi

2018-01-01

To determine whether baseline foveal threshold and photoreceptor integrity can predict best-corrected visual acuity (BCVA) at 12 months after intravitreal aflibercept (IVA) therapy in eyes with neovascular age-related macular degeneration (AMD). We evaluated 25 eyes of 25 patients with treatment-naïve neovascular AMD who received IVA once a month for 3 months, followed by once every 2 months for 8 months. BCVA, integrity of the external limiting membrane (ELM) or the ellipsoid zone (EZ) of the photoreceptors, and retinal sensitivity were determined before (baseline) and at 6 and 12 months after initial IVA. The average threshold foveal sensitivity and mean deviation within the central 10° were determined by Humphrey central 10-2 perimetry. Correlations between BCVA at 12 months and integrity of the ELM or EZ, foveal threshold, and mean deviation at each visit were determined. At 12 months, BCVA improved significantly from 0.20±0.23 to 0.10±0.22 logMAR (logarithm of the minimum angle of resolution) units, and foveal threshold and mean deviation improved significantly from 29.0±5.1 and -3.38±3.10 dB to 32.6±3.2 and -1.64±2.10 dB, respectively ( P =0.0009 and P =0.0021). At baseline, both foveal threshold and integrity of the ELM were significantly correlated with BCVA at 12 months ( P =0.0428 and P =0.0275). These results indicate that both integrity of the ELM and foveal threshold at baseline can predict BCVA after treatment for neovascular AMD. There is a possibility that these parameters can predict the efficacy of IVA in each case.

On the expected discounted penalty functions for two classes of risk processes under a threshold dividend strategy

NASA Astrophysics Data System (ADS)

Lu, Zhaoyang; Xu, Wei; Sun, Decai; Han, Weiguo

2009-10-01

In this paper, the discounted penalty (Gerber-Shiu) functions for a risk model involving two independent classes of insurance risks under a threshold dividend strategy are developed. We also assume that the two claim number processes are independent Poisson and generalized Erlang (2) processes, respectively. When the surplus is above this threshold level, dividends are paid at a constant rate that does not exceed the premium rate. Two systems of integro-differential equations for discounted penalty functions are derived, based on whether the surplus is above this threshold level. Laplace transformations of the discounted penalty functions when the surplus is below the threshold level are obtained. And we also derive a system of renewal equations satisfied by the discounted penalty function with initial surplus above the threshold strategy via the Dickson-Hipp operator. Finally, analytical solutions of the two systems of integro-differential equations are presented.

Reduced critical rotation for resistive-wall mode stabilization in a near-axisymmetric configuration.

PubMed

Reimerdes, H; Garofalo, A M; Jackson, G L; Okabayashi, M; Strait, E J; Chu, M S; In, Y; La Haye, R J; Lanctot, M J; Liu, Y Q; Navratil, G A; Solomon, W M; Takahashi, H; Groebner, R J

2007-02-02

Recent DIII-D experiments with reduced neutral beam torque and minimum nonaxisymmetric perturbations of the magnetic field show a significant reduction of the toroidal plasma rotation required for the stabilization of the resistive-wall mode (RWM) below the threshold values observed in experiments that apply nonaxisymmetric magnetic fields to slow the plasma rotation. A toroidal rotation frequency of less than 10 krad/s at the q=2 surface (measured with charge exchange recombination spectroscopy using C VI) corresponding to 0.3% of the inverse of the toroidal Alfvén time is sufficient to sustain the plasma pressure above the ideal MHD no-wall stability limit. The low-rotation threshold is found to be consistent with predictions by a kinetic model of RWM damping.

EFFECT OF STRAIN FIELD ON THRESHOLD DISPLACEMENT ENERGY OF TUNGSTEN STUDIED BY MOLECULAR DYNAMICS SIMULATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, D.; Gao, Ning; Setyawan, Wahyu

The influence of hydrostatic strain on point defect formation energy and threshold displacement energy (Ed) in body-centered cubic (BCC) tungsten was studied with molecular dynamics simulations. Two different tungsten potentials (Fikar and Juslin) were used. The minimum Ed direction calculated with the Fikar-potential was <100>, but with the Juslin-potential it was <111>. The most stable self-interstitial (SIA) configuration was a <111>-crowdion for both potentials. The stable SIA configuration did not change with applied strain. Varying the strain from compression to tension increased the vacancy formation energy but decreased the SIA formation energy. The SIA formation energy changed more significantly thanmore » for a vacancy such that Ed decreased with applied strain from compression to tension.« less

Thermal constraints to the sporogonic development and altitudinal distribution of avian malaria Plasmodium relictum in Hawai'i.

PubMed

LaPointe, Dennis A; Goff, M Lee; Atkinson, Carter T

2010-04-01

More than half of the Hawaiian honeycreepers (Drepanidinae) known from historical records are now extinct. Introduced mosquito-borne disease, in particular the avian malaria Plasmodium relictum , has been incriminated as a leading cause of extinction during the 20th century and a major limiting factor in the recovery of remaining species populations. Today, most native Hawaiian bird species reach their highest densities and diversity in high elevation (>1,800 m above sea level) forests. We determined the thermal requirements for sporogonic development of P. relictum in the natural vector, Culex quinquefasciatus , and assessed the current distribution of native bird species in light of this information. Sporogonic development was completed at constant laboratory and mean field temperatures between 30 and 17 C, but development, prevalence, and intensity decreased significantly below 21 C. Using a degree-day (DD) model, we estimated a minimum threshold temperature of 12.97 C and a thermal requirement of 86.2 DD as necessary to complete development. Predicted (adiabatic lapse-rate) and observed summer threshold isotherm (13 C) correspond to the elevation of high forest refuges on the islands of Maui and Hawai'i. Our data support the hypothesis that avian malaria currently restricts the altitudinal distribution of Hawaiian honeycreeper populations and provide an ecological explanation for the absence of disease at high elevation.

Theory of vibratory mobilization and break-up of non-wetting fluids entrapped in pore constrictions

NASA Astrophysics Data System (ADS)

Beresnev, I.; Li, W.; Vigil, D.

2006-12-01

Quantitative dynamics of a non-wetting (e. g., NAPL) ganglion entrapped in a pore constriction and subjected to vibrations can be approximated by the equation of motion of an oscillator moving under the effect of the external pressure gradient, inertial oscillatory force, and restoring capillary force. The solution of the equation provides the conditions under which the droplet experiences forced oscillations without being mobilized or is liberated upon the acceleration of the wall exceeding an "unplugging" threshold. This solution provides a quantitative tool for the estimation of the parameters of vibratory fields needed to liberate entrapped non-wetting fluids. For typical pore sizes encountered in reservoirs and aquifers, wall accelerations must exceed at least several m/sec2 and even higher levels to mobilize the droplets of NAPL; however, in the populations of ganglia entrapped in natural porous environments, many may reside very near their mobilization thresholds and may be mobilized by extremely low accelerations as well. For given acceleration, lower seismic frequencies are more efficient. The ganglia may also break up into smaller pieces when passing through pore constrictions. The snap-off is governed by the geometry only; for constrictions with sinusoidal profile (spatial wavelength of L and maximum and minimum radii of rmax and rmin, the break-up occurs if L > 2π(rmin rmax)1/2. Computational fluid dynamics shows the details of the break-up process.

Noise Exposure and Hearing Capabilities of Quarry Workers in Ghana: A Cross-Sectional Study

PubMed Central

Gyamfi, Charles Kwame R.; Amankwaa, Isaac; Owusu Sekyere, Frank; Boateng, Daniel

2016-01-01

Introduction. Although quarry operations have high economic significance, the effects they cause to the workers in terms of excessive noise production cannot be overlooked. This cross-sectional study assessed the extent of noise exposure and its influence on hearing capabilities among quarry workers in Ashanti region. Methods. The study involved 400 workers randomly selected from five quarries in Ashanti region from April to June 2012. Data was collected using structured questionnaires, physical examination, and audiological assessments. A logistic regression model was fitted to assess independent predictors of hearing loss. Results. All the machines used at the various quarries produced noise that exceeded the minimum threshold with levels ranging from 85.5 dBA to 102.7 dBA. 176 (44%) of study respondents had hearing threshold higher than 25 dBA. 18% and 2% of these were moderately (41–55 dBA) and severely (71–90 dBA) impaired, respectively. Age, duration of work, and use of earplugs independently predicted the development of hearing loss. Use of earplugs showed a protective effect on the development of hearing loss (OR = 0.45; 95% CI = 0.25, 0.84). Conclusion. This study provides empirical evidence on the extent of damage caused to quarry workers as a result of excessive noise exposure. This will support the institution of appropriate protective measures to minimize this threat. PMID:26904137

Determination of optimum threshold values for EMG time domain features; a multi-dataset investigation

NASA Astrophysics Data System (ADS)

Nlandu Kamavuako, Ernest; Scheme, Erik Justin; Englehart, Kevin Brian

2016-08-01

Objective. For over two decades, Hudgins’ set of time domain features have extensively been applied for classification of hand motions. The calculation of slope sign change and zero crossing features uses a threshold to attenuate the effect of background noise. However, there is no consensus on the optimum threshold value. In this study, we investigate for the first time the effect of threshold selection on the feature space and classification accuracy using multiple datasets. Approach. In the first part, four datasets were used, and classification error (CE), separability index, scatter matrix separability criterion, and cardinality of the features were used as performance measures. In the second part, data from eight classes were collected during two separate days with two days in between from eight able-bodied subjects. The threshold for each feature was computed as a factor (R = 0:0.01:4) times the average root mean square of data during rest. For each day, we quantified CE for R = 0 (CEr0) and minimum error (CEbest). Moreover, a cross day threshold validation was applied where, for example, CE of day two (CEodt) is computed based on optimum threshold from day one and vice versa. Finally, we quantified the effect of the threshold when using training data from one day and test data of the other. Main results. All performance metrics generally degraded with increasing threshold values. On average, CEbest (5.26 ± 2.42%) was significantly better than CEr0 (7.51 ± 2.41%, P = 0.018), and CEodt (7.50 ± 2.50%, P = 0.021). During the two-fold validation between days, CEbest performed similar to CEr0. Interestingly, when using the threshold values optimized per subject from day one and day two respectively, on the cross-days classification, the performance decreased. Significance. We have demonstrated that threshold value has a strong impact on the feature space and that an optimum threshold can be quantified. However, this optimum threshold is highly data and subject driven and thus do not generalize well. There is a strong evidence that R = 0 provides a good trade-off between system performance and generalization. These findings are important for practical use of pattern recognition based myoelectric control.

Determination of optimum threshold values for EMG time domain features; a multi-dataset investigation.

PubMed

Kamavuako, Ernest Nlandu; Scheme, Erik Justin; Englehart, Kevin Brian

2016-08-01

For over two decades, Hudgins' set of time domain features have extensively been applied for classification of hand motions. The calculation of slope sign change and zero crossing features uses a threshold to attenuate the effect of background noise. However, there is no consensus on the optimum threshold value. In this study, we investigate for the first time the effect of threshold selection on the feature space and classification accuracy using multiple datasets. In the first part, four datasets were used, and classification error (CE), separability index, scatter matrix separability criterion, and cardinality of the features were used as performance measures. In the second part, data from eight classes were collected during two separate days with two days in between from eight able-bodied subjects. The threshold for each feature was computed as a factor (R = 0:0.01:4) times the average root mean square of data during rest. For each day, we quantified CE for R = 0 (CEr0) and minimum error (CEbest). Moreover, a cross day threshold validation was applied where, for example, CE of day two (CEodt) is computed based on optimum threshold from day one and vice versa. Finally, we quantified the effect of the threshold when using training data from one day and test data of the other. All performance metrics generally degraded with increasing threshold values. On average, CEbest (5.26 ± 2.42%) was significantly better than CEr0 (7.51 ± 2.41%, P = 0.018), and CEodt (7.50 ± 2.50%, P = 0.021). During the two-fold validation between days, CEbest performed similar to CEr0. Interestingly, when using the threshold values optimized per subject from day one and day two respectively, on the cross-days classification, the performance decreased. We have demonstrated that threshold value has a strong impact on the feature space and that an optimum threshold can be quantified. However, this optimum threshold is highly data and subject driven and thus do not generalize well. There is a strong evidence that R = 0 provides a good trade-off between system performance and generalization. These findings are important for practical use of pattern recognition based myoelectric control.