Dairy farm effluent effects on urine patch nitrous oxide and carbon dioxide emissions.

PubMed

Clough, Tim J; Kelliher, Francis M

2005-01-01

Dairy farm effluent (DFE) comprises animal feces, urine, and wash-down water collected at the milking shed. This is collected daily during the milking season and sprayed onto grazed dairy pastures. Urine patches in grazed pastures make a significant contribution to anthropogenic N(2)O emissions. The DFE could potentially mitigate N(2)O emissions by influencing the N(2)O to dinitrogen (N(2)) ratio, since it contains water-soluble carbon (WSC). Alternatively, DFE may enhance N(2)O emissions from urine patches. The application of DFE may also provide a substrate for the production of CO(2) in pasture soils. The effects of DFE on the CO(2) and N(2)O emissions from urine patches are unknown. Thus a laboratory experiment was performed where repeated DFE applications were made to repacked soil cores. Dairy farm effluent was applied at 0, 7, or 14 d after urine deposition. The urine was applied once on Day 0. Urine contained (15)N-enriched urea. Measurements of N(2)O, N(2), and carbon dioxide (CO(2)) fluxes, soil pH, and soil inorganic N concentrations were made. After 43 d the DFE had not mitigated N(2)O fluxes from urine patches. A small increase in the N(2)O flux occurred from the urine-treated soils where DFE was applied 1 wk after urine deposition. The amount of WSC applied in the DFE proved to be insignificant compared with the amount of soil C released as CO(2) following urine application. The priming of soil C in urine patches has implications for the understanding of soil C processes in grazed pasture ecosystems and the budgeting of C within these ecosystems.

Design for the Environment Products (Raw Data)

EPA Pesticide Factsheets

This dataset contains a list of products that carry the Design for the Environment (DfE) label. This mark enables consumers to quickly identify and choose products that can help protect the environment and are safer for families. When you see the DfE logo on a product it means that the DfE scientific review team has screened each ingredient for potential human health and environmental effects and that-based on currently available information, EPA predictive models, and expert judgment-the product contains only those ingredients that pose the least concern among chemicals in their class. Product manufacturers who become DfE partners, and earn the right to display the DfE logo on recognized products, have invested heavily in research, development and reformulation to ensure that their ingredients and finished product line up on the green end of the health and environmental spectrum while maintaining or improving product performance. EPA's Design for the Environment Program (DfE) has allowed use of their logo on over 2500 products. These products are formulated from the safest possible ingredients and have reduced the use of chemicals of concern by hundreds of millions of pounds. A Spanish version of this dataset is available for download at http://www.epa.gov/dfe/pubs/products/list_of_labeled_products.html

Inhibitory effects of Drynaria fortunei extract on house dust mite antigen-induced atopic dermatitis in NC/Nga mice.

PubMed

Sung, Yoon-Young; Kim, Dong-Seon; Yang, Won-Kyung; Nho, Kyoung Jin; Seo, Hyeong Seok; Kim, Young Sang; Kim, Ho Kyoung

2012-10-31

Drynaria fortunei (Kunze) J. Sm has been widely used in traditional medicine for the treatment of inflammation, hyperlipidemia, arteriosclerosis, rheumatism, and bone healing. We investigated the anti-inflammatory effects of a 70% ethanol extract of Drynaria fortunei (DFE). We evaluated the anti-inflammatory effects of topically applied DFE on house dust mite Dermatophargoides farinae-induced atopic dermatitis-like skin lesions in NC/Nga mice. Treatment of NC/Nga mice with DFE reduced the dermatitis score, ear thickness, and serum levels of IgE, IgG1, and IL-6. Histopathological analyses of ear and skin lesions showed inhibition of the thickening of the epidermis and reduced epidermal/dermal infiltration of inflammatory cells. In ear lesions, mRNA expression levels of IL-4, IL-6, and tumor necrosis factor-α were reduced by DFE treatment. DFE inhibited the development of dermatitis-like skin lesions in NC/Nga mice. These results suggest that DFE may be a therapeutic candidate for the treatment of AD. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Fatal cardiac arrhythmia after repeated exposure to 1,1-difluoroethane (DFE).

PubMed

Avella, Joseph; Wilson, James C; Lehrer, Michael

2006-03-01

A 42-year-old man was found dead after repeated exposure to 1,1-difluoroethane (DFE, Freon 152a), a propellant found in CRC Duster, a product intended for the removal of dust and lint. Toxicologic analysis detected DFE in femoral blood 136.3 mg/L, brain 117.5 mg/kg, liver 87.6 mg/kg, lung 60.3 mg/kg, adipose 235.7 mg/kg, and vitreous fluid 25.1 mg/L. The cause of death was determined to be a fatal cardiac arrhythmia due to intoxication with 1,1-difluoroethane. After comparison to previously published cases involving DFE, we suggest that analysis of adipose tissue for DFE and similar compounds, along with blood and other tissues, may be useful in distinguishing between acute versus chronic exposure. Adipose may also be a valuable alternate specimen for detection in cases where loss or elimination from blood is likely to have occurred.

Frequency-Domain Channel Estimation and Equalization for Single Carrier Underwater Acoustic Communications

DTIC Science & Technology

2007-01-01

synchronization ; vm(k) white Gaussian noise with average power σ2. If the Doppler shift f m,k is significant, then it causes the received signal ym(k) to be time ...intersymbol interference (ISI) to extend over 20-300 symbols at a data rate of 2-10 kilosymbols per second. Another obstacle is the time -varying Doppler... synchronization that employs a phase-locked loop (PLL) or delay-locked loop (DLL). However, the DFE and PLL/DLL have to interact in a nonlinear fashion

78 FR 68056 - Information Collection Request Submitted to OMB for Review and Approval; Comment Request; EPA's...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-13

... Request Submitted to OMB for Review and Approval; Comment Request; EPA's Design for the Environment (DfE... Environment (DfE) Logo Redesign Consultations'' (EPA ICR No. 2487.01, OMB Control No. 2070-NEW) to the Office... (EPA) will select a revised logo and messaging for its Design for the Environment (DfE) program. A key...

77 FR 65683 - Agency Information Collection Activities; Submission to OMB for Review and Approval; Comment...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-30

... Activities; Submission to OMB for Review and Approval; Comment Request; EPA's Design for the Environment (DfE... Budget (OMB) for review and approval: EPA's Design for the Environment (DfE) Partner of the Year Awards... . Title: EPA's Design for the Environment (DfE) Partner of the Year Awards Program. ICR Status: This is a...

Design for the Environment Products (Online Search)

EPA Pesticide Factsheets

This dataset contains a list of products that carry the Design for the Environment (DfE) label. This mark enables consumers to quickly identify and choose products that can help protect the environment and are safer for families. When you see the DfE logo on a product it means that the DfE scientific review team has screened each ingredient for potential human health and environmental effects and that-based on currently available information, EPA predictive models, and expert judgment-the product contains only those ingredients that pose the least concern among chemicals in their class. Product manufacturers who become DfE partners, and earn the right to display the DfE logo on recognized products, have invested heavily in research, development and reformulation to ensure that their ingredients and finished product line up on the green end of the health and environmental spectrum while maintaining or improving product performance. EPA's Design for the Environment Program (DfE) has allowed use of their logo on over 2500 products. These products are formulated from the safest possible ingredients and have reduced the use of chemicals of concern by hundreds of millions of pounds.

Inference of the Distribution of Selection Coefficients for New Nonsynonymous Mutations Using Large Samples

PubMed Central

Kim, Bernard Y.; Huber, Christian D.; Lohmueller, Kirk E.

2017-01-01

The distribution of fitness effects (DFE) has considerable importance in population genetics. To date, estimates of the DFE come from studies using a small number of individuals. Thus, estimates of the proportion of moderately to strongly deleterious new mutations may be unreliable because such variants are unlikely to be segregating in the data. Additionally, the true functional form of the DFE is unknown, and estimates of the DFE differ significantly between studies. Here we present a flexible and computationally tractable method, called Fit∂a∂i, to estimate the DFE of new mutations using the site frequency spectrum from a large number of individuals. We apply our approach to the frequency spectrum of 1300 Europeans from the Exome Sequencing Project ESP6400 data set, 1298 Danes from the LuCamp data set, and 432 Europeans from the 1000 Genomes Project to estimate the DFE of deleterious nonsynonymous mutations. We infer significantly fewer (0.38–0.84 fold) strongly deleterious mutations with selection coefficient |s| > 0.01 and more (1.24–1.43 fold) weakly deleterious mutations with selection coefficient |s| < 0.001 compared to previous estimates. Furthermore, a DFE that is a mixture distribution of a point mass at neutrality plus a gamma distribution fits better than a gamma distribution in two of the three data sets. Our results suggest that nearly neutral forces play a larger role in human evolution than previously thought. PMID:28249985

The removal of arsenate from water using iron-modified diatomite (D-Fe): isotherm and column experiments.

PubMed

Pantoja, M L; Jones, H; Garelick, H; Mohamedbakr, H G; Burkitbayev, M

2014-01-01

Iron hydroxide supported onto porous diatomite (D-Fe) is a low-cost material with potential to remove arsenic from contaminated water due to its affinity for the arsenate ion. This affinity was tested under varying conditions of pH, contact time, iron content in D-Fe and the presence of competitive ions, silicate and phosphate. Batch and column experiments were conducted to derive adsorption isotherms and breakthrough behaviours (50 μg L(-1)) for an initial concentration of 1,000 μg L(-1). Maximum capacity at pH 4 and 17% iron was 18.12-40.82 mg of arsenic/g of D-Fe and at pH 4 and 10% iron was 18.48-29.07 mg of arsenic/g of D-Fe. Adsorption decreased in the presence of phosphate and silicate ions. The difference in column adsorption behaviour between 10% and 17% iron was very pronounced, outweighing the impact of all other measured parameters. There was insufficient evidence of a correlation between iron content and arsenic content in isotherm experiments, suggesting that ion exchange is a negligible process occurring in arsenate adsorption using D-Fe nor is there co-precipitation of arsenate by rising iron content of the solute above saturation.

Importance of Ekman transport and gyre circulation change on seasonal variation of surface dissolved iron in the western subarctic North Pacific

NASA Astrophysics Data System (ADS)

Nakanowatari, Takuya; Nakamura, Tomohiro; Uchimoto, Keisuke; Nishioka, Jun; Mitsudera, Humio; Wakatsuchi, Masaaki

2017-05-01

Iron (Fe) is an essential nutrient for marine phytoplankton and it constitutes an important element in the marine carbon cycle in the ocean. This study examined the mechanisms controlling seasonal variation of dissolved Fe (dFe) in the western subarctic North Pacific (WSNP), using an ocean general circulation model coupled with a simple biogeochemical model incorporating a dFe cycle fed by two major sources (atmospheric dust and continental shelf sediment). The model reproduced the seasonal cycle of observed concentrations of dFe and macronutrients at the surface in the Oyashio region with maxima in winter (February-March) and minima in summer (July-September), although the simulated seasonal amplitudes are a half of the observed values. Analysis of the mixed-layer dFe budget indicated that both local vertical entrainment and lateral advection are primary contributors to the wintertime increase in dFe concentration. In early winter, strengthened northwesterly winds excite southward Ekman transport and Ekman upwelling over the western subarctic gyre, transporting dFe-rich water southward. In mid to late winter, the southward western boundary current of the subarctic gyre and the outflow from the Sea of Okhotsk also bring dFe-rich water to the Oyashio region. The contribution of atmospheric dust to the dFe budget is several times smaller than these ocean transport processes in winter. These results suggest that the westerly wind-induced Ekman transport and gyre circulation systematically influence the seasonal cycle of WSNP surface dFe concentration.

A validated method for the quantitation of 1,1-difluoroethane using a gas in equilibrium method of calibration.

PubMed

Avella, Joseph; Lehrer, Michael; Zito, S William

2008-10-01

1,1-Difluoroethane (DFE), also known as Freon 152A, is a member of a class of compounds known as halogenated hydrocarbons. A number of these compounds have gained notoriety because of their ability to induce rapid onset of intoxication after inhalation exposure. Abuse of DFE has necessitated development of methods for its detection and quantitation in postmortem and human performance specimens. Furthermore, methodologies applicable to research studies are required as there have been limited toxicokinetic and toxicodynamic reports published on DFE. This paper describes a method for the quantitation of DFE using a gas chromatography-flame-ionization headspace technique that employs solventless standards for calibration. Two calibration curves using 0.5 mL whole blood calibrators which ranged from A: 0.225-1.350 to B: 9.0-180.0 mg/L were developed. These were evaluated for linearity (0.9992 and 0.9995), limit of detection of 0.018 mg/L, limit of quantitation of 0.099 mg/L (recovery 111.9%, CV 9.92%), and upper limit of linearity of 27,000.0 mg/L. Combined curve recovery results of a 98.0 mg/L DFE control that was prepared using an alternate technique was 102.2% with CV of 3.09%. No matrix interference was observed in DFE enriched blood, urine or brain specimens nor did analysis of variance detect any significant differences (alpha = 0.01) in the area under the curve of blood, urine or brain specimens at three identical DFE concentrations. The method is suitable for use in forensic laboratories because validation was performed on instrumentation routinely used in forensic labs and due to the ease with which the calibration range can be adjusted. Perhaps more importantly it is also useful for research oriented studies because the removal of solvent from standard preparation eliminates the possibility for solvent induced changes to the gas/liquid partitioning of DFE or chromatographic interference due to the presence of solvent in specimens.

Prospective randomized controlled trial comparing the outcomes and costs of two eyecare adherence interventions in diabetes patients.

PubMed

Pizzi, Laura T; Zangalli, Camila S; Murchison, Ann P; Hale, Nicole; Hark, Lisa; Dai, Yang; Leiby, Benjamin E; Haller, Julia A

2015-04-01

Diabetic retinopathy is one of the leading causes of vision impairment among adults in the USA. While it is suggested that diabetics receive annual dilated fundus examinations (DFE), many patients do not adhere to these recommendations. This paper investigates the outcomes and costs of an educational and telephone intervention on DFE follow-up adherence in patients with diabetes. In a prospective trial, 356 diabetic patients due for a DFE at an urban eye clinic were randomly assigned to usual care (UC; reference case), mailed intervention (MI), or telephone intervention (TI). UC patients (n = 119) received a standard form letter. MI patients (n = 117) received a personalized letter encouraging scheduling of an eye examination with an educational brochure about diabetic eye disease. TI patients (n = 120) received personal calls (up to three attempts) to schedule a follow-up with standard form letter. The primary outcome was obtaining a DFE within 90 days of suggested return. Costs (US$ 2013) included time costs for staff, phone charges, supplies, and postage. Since TI involved greater cost components compared to MI, univariate sensitivity analysis examined the impact of reducing phone costs. Patients were mostly female (66 %) and African American (70 %) with a mean age of 61 years. TI patients were more likely to schedule DFE [65 vs. 42 %; relative risk (RR) 1.54; CI 1.20-1.96; P < 0.001] versus UC patients. Obtaining a DFE within 90 days of suggested return was also significantly higher among TI patients compared to UC patients (51 vs. 36 %, RR 1.41; CI 1.05-1.89; P = 0.024). MI patients were slightly less likely to schedule DFE versus UC patients (38 vs. 42 %, RR 0.90; CI 0.66-1.22; P = NSS) and obtain a DFE (32 vs. 36 %; RR 0.90; CI 0.63-1.28; P = NSS). The total cost of TI was US$798.28 or US$6.65/patient and the cost/follow-up DFE was US$26.05. Sensitivity analyses revealed that the cost/follow-up can be greatly reduced but remains greater compared to UC (US$2.76 if US$0.25/call, US$11.13 if $1/call; US$22.29 if US$2/call). Personal phone assistance in scheduling DFE follow-up is more effective but also more costly. Follow-up research has been initiated to determine whether automated phone reminders can achieve similar effectiveness at a lower cost.

Consistent force field modeling of matrix isolated molecules. V. Minimum energy path potential to the conformer conversion of 1,2-difluoroethane: Ar 364, ab initio calculation of electric multipole moments and electric polarization contribution to the conversion barrier

NASA Astrophysics Data System (ADS)

Gunde, R.; Ha, T.-K.; Günthard, H. H.

1990-08-01

In this paper results of consistent force field modeling (CFF) of the potential function to conversion of the gauche (g) to the trans (t) conformer of 1,2-difluoroethane (DFE) isolated in an argon matrix will be reported. Starting point are locally stable configurations gDFE:Ar 364 (defect GH1) and tDFE:Ar 364 (TH1) obtained in previous work from CFF modeling of a cube shaped Ar 364 fragment containing one DFE molecule in its center. Using the dihedral angle of DFE as an independent parameter the minimum energy path of the conversion process gDFE:Ar 364→tDFE:Ar 364 will be determined by CFF energy minimization. Determination of the minimum energy path is found to require large numbers of energy minimization steps and to lead to a rather complicated motion of the molecule with respect to the crystal fragment. Surprisingly the molecule-matrix interactions lead to a reduction of the g-t barrier by ≈500 cal/mol and to a stabilization of the trans species by ≈500 cal/mol. This finding is a consequence of a delicate interplay of matrix-molecule and matrix-matrix interactions. Calculation of the electric polarization energy (induced dipole-first-order polarization approximation) is based on extended ab initio calculations of dipole and quadrupole moments and a bond polarizability estimate of the first-order polarizability of DFE as a function of the internal rotation angle, on Fourier expansion of multipole components and use of symmetry for reduction of the order of the linear system defining the (self-consistent) induced dipole moments of all Ar atoms. Electric polarization is found to alter the potential function of the conversion process in a profound way: the g-t barrier and the t-g energy difference are increased to ≈3000 cal/mol and to ≈1500 cal/mol respectively (≈2500 and ≈530 cal/mol respectively for free DFE). Further applications of the technique developed in this work to related problems of matrix isolated molecules, e.g., vibrational matrix shifts will be discussed.

The 3D Distribution of Dissolved and Colloidal Fe, Mn, Zn, Cu, Ni, Cd and Pb in the Western Antarctic Peninsula Shelf Region; Implications for Natural Fe Fertilization

NASA Astrophysics Data System (ADS)

Sherrell, R. M.; Fitzsimmons, J. N.; Roccanova, J.; Schofield, O.; Meredith, M. P.

2016-02-01

The Western Antarctic Peninsula (WAP) shelf region is is a natural Fe fertilization zone where primary production exceeds that of the adjacent open Southern Ocean. Until recently, however, distributions of Fe and of other bioactive metals were completely lacking for the WAP, and the sources and delivery mechanisms of Fe to the euphotic zone were only speculated upon. We have previously presented surface water (2m) dissolved (dTM, <0.2µm) and particulate (pTM, >0.45µm) distributions for Fe and a suite of other bioactive metals over the WAP shelf, covering the Palmer LTER sampling grid for Jan. 2010, 2011 and 2012. We now report the first complete 3D distribution of dissolved and colloidal Fe (and Mn, Zn, Cu, Ni, Cd and Pb) over the LTER grid in Jan. 2015, allowing assessment of dFe size speciation, sources and transport pathways in this dynamic shelf system. Dissolved metals were analyzed by automated offline preconcentration (seaFAST-pico, ESI) followed by sector-field ICP-MS. We confirm previous findings of low ( 0.1nM) dFe in surface waters on the mid-outer shelf in the northern portion of the grid, and now find that concentrations at this level or below persist through the euphotic zone. However, dFe increases rapidly with depth, with low surface values underlain by substantially higher concentrations even at 50m. Inner shelf surface waters are generally substantially > 0.1nM, suggesting Fe replete conditions in this region. Vertical profiles reveal that dFe generally increases with depth, much moreso in the inner shelf (dFe up to 5.0nM) than the outer shelf. A general N-S gradient in dFe is also evident, with concentrations higher in the southern WAP, especially in Marguerite Bay. In addition, shelf stations often show a dFe maximum suggesting remineralization from sinking biogenic particles. These findings for dFe and for the other metals, will be used to help unravel the biogeochemical workings of natural Fe fertilization in this region.

Aqueous Date Flesh or Pits Extract Attenuates Liver Fibrosis via Suppression of Hepatic Stellate Cell Activation and Reduction of Inflammatory Cytokines, Transforming Growth Factor-β1 and Angiogenic Markers in Carbon Tetrachloride-Intoxicated Rats

PubMed Central

Al-Rasheed, Nouf M.; Attia, Hala A.; Mohamad, Raeesa A.; Al-Rasheed, Nawal M.; Al-Amin, Maha A.; AL-Onazi, Asma

2015-01-01

Previous data indicated the protective effect of date fruit extract on oxidative damage in rat liver. However, the hepatoprotective effects via other mechanisms have not been investigated. This study was performed to evaluate the antifibrotic effect of date flesh extract (DFE) or date pits extract (DPE) via inactivation of hepatic stellate cells (HSCs), reducing the levels of inflammatory, fibrotic and angiogenic markers. Coffee was used as reference hepatoprotective agent. Liver fibrosis was induced by injection of CCl4 (0.4 mL/kg) three times weekly for 8 weeks. DFE, DPE (6 mL/kg), coffee (300 mg/kg), and combination of coffee + DFE and coffee + DPE were given to CCl4-intoxicated rats daily for 8 weeks. DFE, DPE, and their combination with coffee attenuated the elevated levels of inflammatory cytokines including tumor necrosis factor-α, interleukin-6, and interleukin-1β. The increased levels of transforming growth factor-β1 and collagen deposition in injured liver were alleviated by both extracts. CCl4-induced expression of α-smooth muscle actin was suppressed indicating HSCs inactivation. Increased angiogenesis was ameliorated as revealed by reduced levels and expression of vascular endothelial growth factor and CD31. We concluded that DFE or DPE could protect liver via different mechanisms. The combination of coffee with DFE or DPE may enhance its antifibrotic effects. PMID:25945106

Methane emissions and contaminant degradation rates at sites affected by accidental releases of denatured fuel-grade ethanol

NASA Astrophysics Data System (ADS)

Sihota, Natasha J.; Mayer, K. Ulrich; Toso, Mark A.; Atwater, Joel F.

2013-08-01

The recent increase in the use of denatured fuel-grade ethanol (DFE) has enhanced the probability of its environmental release. Due to the highly labile nature of ethanol (EtOH), it is expected to rapidly biodegrade, increasing the potential for inducing methanogenic conditions in the subsurface. As environmental releases of DFE can be expected to occur at the ground surface or in the vadose zone (e.g., due to surficial spills from rail lines or tanker trucks and leaking underground storage tanks), the potential for methane (CH4) generation at DFE spill sites requires evaluation. An assessment is needed because high CH4 generation rates may lead to CH4 fluxes towards the ground surface, which is of particular concern if spills are located close to human habitation—related to concerns of soil vapor intrusion (SVI). This work demonstrates, for the first time, the measurement of surficial gas release rates at large volume DFE spill sites. Two study sites, near Cambria and Balaton, in MN are investigated. Total carbon emissions at the ground surface (summing carbon dioxide (CO2) and CH4 emissions) are used to quantify depth-integrated DFE degradation rates. Results from both sites demonstrate that substantial CO2 and CH4 emissions do occur—even years after a spill. However, large total carbon fluxes, and CH4 emissions in particular, were restricted to a localized area within the DFE source zone. At the Balaton site, estimates of total DFE carbon losses in the source zone ranged between 5 and 174 μmol m- 2 s- 1, and CH4 effluxes ranged between non-detect and 9 μmol m- 2 s- 1. At the Cambria site estimates of total DFE carbon losses in the source zone ranged between 8 and 500 μmol m- 2 s- 1, and CH4 effluxes ranged between non-detect and 393 μmol m- 2 s- 1. Substantial CH4 accumulation, coupled with oxygen (O2) depletion, measured in samples collected from custom-designed gas collection chambers at the Cambria site suggests that the development of explosion or asphyxiation hazards is possible in confined spaces above a rapidly degrading DFE release. However, the results also indicate that the development of such hazards is locally constrained, will require a high degree of soil moisture, close proximity to the source zone, a good connection between the soil and the confined space, and poorly aerated conditions.

Methane emissions and contaminant degradation rates at sites affected by accidental releases of denatured fuel-grade ethanol.

PubMed

Sihota, Natasha J; Mayer, K Ulrich; Toso, Mark A; Atwater, Joel F

2013-08-01

The recent increase in the use of denatured fuel-grade ethanol (DFE) has enhanced the probability of its environmental release. Due to the highly labile nature of ethanol (EtOH), it is expected to rapidly biodegrade, increasing the potential for inducing methanogenic conditions in the subsurface. As environmental releases of DFE can be expected to occur at the ground surface or in the vadose zone (e.g., due to surficial spills from rail lines or tanker trucks and leaking underground storage tanks), the potential for methane (CH4) generation at DFE spill sites requires evaluation. An assessment is needed because high CH4 generation rates may lead to CH4 fluxes towards the ground surface, which is of particular concern if spills are located close to human habitation-related to concerns of soil vapor intrusion (SVI). This work demonstrates, for the first time, the measurement of surficial gas release rates at large volume DFE spill sites. Two study sites, near Cambria and Balaton, in MN are investigated. Total carbon emissions at the ground surface (summing carbon dioxide (CO2) and CH4 emissions) are used to quantify depth-integrated DFE degradation rates. Results from both sites demonstrate that substantial CO2 and CH4 emissions do occur-even years after a spill. However, large total carbon fluxes, and CH4 emissions in particular, were restricted to a localized area within the DFE source zone. At the Balaton site, estimates of total DFE carbon losses in the source zone ranged between 5 and 174 μmol m(-2) s(-1), and CH4 effluxes ranged between non-detect and 9 μmol m(-2) s(-1). At the Cambria site estimates of total DFE carbon losses in the source zone ranged between 8 and 500 μmol m(-2) s(-1), and CH4 effluxes ranged between non-detect and 393 μmol m(-2) s(-1). Substantial CH4 accumulation, coupled with oxygen (O2) depletion, measured in samples collected from custom-designed gas collection chambers at the Cambria site suggests that the development of explosion or asphyxiation hazards is possible in confined spaces above a rapidly degrading DFE release. However, the results also indicate that the development of such hazards is locally constrained, will require a high degree of soil moisture, close proximity to the source zone, a good connection between the soil and the confined space, and poorly aerated conditions. Copyright © 2013 Elsevier B.V. All rights reserved.

Capacity of humic substances to complex with iron at different salinities in the Yangtze River estuary and East China Sea.

PubMed

Yang, Rujun; Su, Han; Qu, Shenglu; Wang, Xuchen

2017-05-03

The iron binding capacities (IBC) of fulvic acid (FA) and humic acid (HA) were determined in the salinity range from 5 to 40. The results indicated that IBC decreased while salinity increased. In addition, dissolved iron (dFe), FA and HA were also determined along the Yangtze River estuary's increasing salinity gradient from 0.14 to 33. The loss rates of dFe, FA and HA in the Yangtze River estuary were up to 96%, 74%, and 67%, respectively. The decreases in dFe, FA and HA, as well as the change in IBC of humic substances (HS) along the salinity gradient in the Yangtze River estuary were all well described by a first-order exponential attenuation model: y(dFe/FA/HA, S) = a 0 × exp(kS) + y 0 . These results indicate that flocculation of FA and HA along the salinity gradient resulted in removal of dFe. Furthermore, the exponential attenuation model described in this paper can be applied in the major estuaries of the world where most of the removal of dFe and HS occurs where freshwater and seawater mix.

A motor vehicle accident fatality involving the inhalation of 1,1-difluoroethane.

PubMed

Hahn, Timothy; Avella, Joseph; Lehrer, Michael

2006-10-01

A 24-year-old female driver with a history of substance abuse was pronounced dead following a single car motor vehicle accident. A surviving front seat passenger witnessed the decedent inhaling "Dust Off" cleaner just prior to losing control of the vehicle. The propellant compound used in this product is the halogenated hydrocarbon 1,1-difluoroethane (DFE). Sealed autopsy specimens were examined for the presence and subsequent quantitation of DFE utilizing an Agilent 6850 gas chromatograph (GC)-flame-ionization detector. The levels of DFE obtained were as follows: 29.8 mg/L in femoral blood, 40.3 mg/L in pulmonary arterial blood, 85.6 mg/L in aortic blood, 79.9 mg/L in chest cavity blood, 21.2 mg/L in vitreous, 11.7 mg/kg in brain, 27.9 mg/kg in liver, 71.0 mg/L in urine, and 51.8 mg/total gastric contents. The presence of DFE was confirmed in the decedent's urine by injection on an Agilent 6890/5973 GC-mass spectrometer in full scan mode. This case presents a uniquely witnessed observation of the apparent impairing effects and consequences of the acute inhalation of halogenated hydrocarbons such as DFE and the operation of a motor vehicle. The proximity of time of death to inhalant use may also provide insight to postmortem distribution patterns of DFE in relation to normal physiologic blood flow. With further investigations, estimating the time of final use of an inhalant prior to death may be deciphered from such patterns, although a degree of caution should be applied in deaths resulting from severe trauma in which normal tissue structure is compromised because postmortem redistribution may result.

Hierarchically three-dimensional (3D) nanotubular sea urchin-shaped iron oxide and its application in heavy metal removal and solar-induced photocatalytic degradation.

PubMed

Lee, Soon Chang; Jeong, Yesul; Kim, Youn Jung; Kim, Hyeran; Lee, Hyun Uk; Lee, Young-Chul; Lee, Sang Moon; Kim, Hae Jin; An, Ha-Rim; Ha, Myoung Gyu; Lee, Go-Woon; Lee, Young-Seak; Lee, Gaehang

2018-04-23

In this study, hierarchically three-dimensional (3D) nanotubular sea urchin-shaped iron oxide nanostructures (3D-Fe 2 O 3 ) were synthesized by a facile and rapid ultrasound irradiation method. Additives, templates, inert gas atmosphere, pH regulation, and other complicated procedures were not required. Dense 3D-Fe 2 O 3 with a relatively large Brunauer-Emmett-Teller (BET) surface area of 129.4 m 2 /g was synthesized within 23 min, and the BET surface area was further improved to 282.7 m 2 /g by a post heat-treatment process. In addition, this post processing led to phase changes from maghemite (γ phase) to hematite (α phase) Fe 2 O 3 . Subsequent characterization suggested that the growth mechanism of the 3D-Fe 2 O 3 follows self-assembly and oriented attachment. The prepared 3D-Fe 2 O 3 was applied to wastewater purification. Ultrasound-irradiated 3D-Fe 2 O 3 can eliminate a As(V) and Cr(VI) from water with 25 times faster removal rate by using a one third smaller amount than commercial α-Fe 2 O 3 . This was attributed to the inter-particle pores and relatively positively charged surface of the nanostructure. In addition, post heat treatment on ultrasound-irradiated 3D-Fe 2 O 3 significantly influenced the photocatalytic degradation of methylene blue and phenol, with a 25 times higher removal efficiency than that of commercial α-Fe 2 O 3 , because of both high BET surface area and good crystallization of the prepared samples. Copyright © 2018 Elsevier B.V. All rights reserved.

Study of CNG/diesel dual fuel engine's emissions by means of RBF neural network.

PubMed

Liu, Zhen-tao; Fei, Shao-mei

2004-08-01

Great efforts have been made to resolve the serious environmental pollution and inevitable declining of energy resources. A review of Chinese fuel reserves and engine technology showed that compressed natural gas (CNG)/diesel dual fuel engine (DFE) was one of the best solutions for the above problems at present. In order to study and improve the emission performance of CNG/diesel DFE, an emission model for DFE based on radial basis function (RBF) neural network was developed which was a black-box input-output training data model not require priori knowledge. The RBF centers and the connected weights could be selected automatically according to the distribution of the training data in input-output space and the given approximating error. Studies showed that the predicted results accorded well with the experimental data over a large range of operating conditions from low load to high load. The developed emissions model based on the RBF neural network could be used to successfully predict and optimize the emissions performance of DFE. And the effect of the DFEmain performance parameters, such as rotation speed, load, pilot quantity and injection timing, were also predicted by means of this model. In resumé, an emission prediction model for CNG/diesel DFE based on RBF neural network was built for analyzing the effect of the main performance parameters on the CO, NOx, emissions of DFE. The predicted results agreed quite well with the traditional emissions model, which indicated that the model had certain application value, although it still has some limitations, because of its high dependence on the quantity of the experimental sample data.

Finite element modelling to assess the effect of surface mounted piezoelectric patch size on vibration response of a hybrid beam

NASA Astrophysics Data System (ADS)

Rahman, N.; Alam, M. N.

2018-02-01

Vibration response analysis of a hybrid beam with surface mounted patch piezoelectric layer is presented in this work. A one dimensional finite element (1D-FE) model based on efficient layerwise (zigzag) theory is used for the analysis. The beam element has eight mechanical and a variable number of electrical degrees of freedom. The beams are also modelled in 2D-FE (ABAQUS) using a plane stress piezoelectric quadrilateral element for piezo layers and a plane stress quadrilateral element for the elastic layers of hybrid beams. Results are presented to assess the effect of size of piezoelectric patch layer on the free and forced vibration responses of thin and moderately thick beams under clamped-free and clamped-clamped configurations. The beams are subjected to unit step loading and harmonic loading to obtain the forced vibration responses. The vibration control using in phase actuation potential on piezoelectric patches is also studied. The 1D-FE results are compared with the 2D-FE results.

The contribution of the mitochondrial genome to sex-specific fitness variance.

PubMed

Smith, Shane R T; Connallon, Tim

2017-05-01

Maternal inheritance of mitochondrial DNA (mtDNA) facilitates the evolutionary accumulation of mutations with sex-biased fitness effects. Whereas maternal inheritance closely aligns mtDNA evolution with natural selection in females, it makes it indifferent to evolutionary changes that exclusively benefit males. The constrained response of mtDNA to selection in males can lead to asymmetries in the relative contributions of mitochondrial genes to female versus male fitness variation. Here, we examine the impact of genetic drift and the distribution of fitness effects (DFE) among mutations-including the correlation of mutant fitness effects between the sexes-on mitochondrial genetic variation for fitness. We show how drift, genetic correlations, and skewness of the DFE determine the relative contributions of mitochondrial genes to male versus female fitness variance. When mutant fitness effects are weakly correlated between the sexes, and the effective population size is large, mitochondrial genes should contribute much more to male than to female fitness variance. In contrast, high fitness correlations and small population sizes tend to equalize the contributions of mitochondrial genes to female versus male variance. We discuss implications of these results for the evolution of mitochondrial genome diversity and the genetic architecture of female and male fitness. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

Opposing authigenic controls on the isotopic signature of dissolved iron in hydrothermal plumes

NASA Astrophysics Data System (ADS)

Lough, A. J. M.; Klar, J. K.; Homoky, W. B.; Comer-Warner, S. A.; Milton, J. A.; Connelly, D. P.; James, R. H.; Mills, R. A.

2017-04-01

Iron is a scarce but essential micronutrient in the oceans that limits primary productivity in many regions of the surface ocean. The mechanisms and rates of Fe supply to the ocean interior are still poorly understood and quantified. Iron isotope ratios of different Fe pools can potentially be used to trace sources and sinks of the global Fe biogeochemical cycle if these boundary fluxes have distinct signatures. Seafloor hydrothermal vents emit metal rich fluids from mid-ocean ridges into the deep ocean. Iron isotope ratios have the potential to be used to trace the input of hydrothermal dissolved iron to the oceans if the local controls on the fractionation of Fe isotopes during plume dispersal in the deep ocean are understood. In this study we assess the behaviour of Fe isotopes in a Southern Ocean hydrothermal plume using a sampling program of Total Dissolvable Fe (TDFe), and dissolved Fe (dFe). We demonstrate that δ56Fe values of dFe (δ56dFe) within the hydrothermal plume change dramatically during early plume dispersal, ranging from -2.39 ± 0.05‰ to -0.13 ± 0.06‰ (2 SD). The isotopic composition of TDFe (δ56TDFe) was consistently heavier than dFe values, ranging from -0.31 ± 0.03‰ to 0.78 ± 0.05‰, consistent with Fe oxyhydroxide precipitation as the plume samples age. The dFe present in the hydrothermal plume includes stabilised dFe species with potential to be transported to the deep ocean. We estimate that stable dFe exported from the plume will have a δ56Fe of -0.28 ± 0.17‰. Further, we show that the proportion of authigenic iron-sulfide and iron-oxyhydroxide minerals precipitating in the buoyant plume exert opposing controls on the resultant isotope composition of dissolved Fe passed into the neutrally buoyant plume. We show that such controls yield variable dissolved Fe isotope signatures under the authigenic conditions reported from modern vent sites elsewhere, and so ought to be considered during iron isotope reconstructions of past hydrothermalism from ocean sediment records.

[Three-dimensional finite element analysis of three conjunctive methods of free iliac bone graft for established mandibular body defects].

PubMed

Wang, Dong; Yang, Zhuang-qun; Hu, Xiao-yi

2007-08-01

To analyze the stress and displacement distribution of 3D-FE models in three conjunctive methods of vascularized iliac bone graft for established mandibular body defects. Using computer image process technique, a series of spiral CT images were put into Ansys preprocess programe to establish three 3D-FE models of different conjunctions. The three 3D-FE models of established mandibular body defects by vascularized iliac bone graft were built up. The distribution of Von Mises stress and displacement around mandibular segment, grafted ilium, plates and screws was obtained. It may be determined successfully that the optimal conjunctive shape be the on-lay conjunction.

Monitoring propranolol treatment in periocular infantile haemangioma.

PubMed

Burne, R; Taylor, R

2014-11-01

To develop a tool for assessing amblyopic risk and monitoring the treatment effect of propranolol in periocular haemangioma management. We present a study of nine children with periocular haemangioma who underwent propranolol treatment at York Hospital between 2009 and 2013.A proposed measure of amblyogenic risk based on the induced anisometropia resulting from a periocular haemangioma was calculated in the form of a single quantitative value, measured in dioptres. This calculation used published work and developed it to produce a new function, termed the delta defocus equivalent (DFE-∂).Refraction measurements were retrospectively collected from patients' notes in order to measure the trend of DFE-∂ over the treatment period with propranolol. The average DFE-∂ at commencement of propranolol was 1.54 (±0.62) D. The average at the end of treatment was 0.39 (±0.38) D. This work presents a possible tool for assessing amblyopic risk in cases of periocular infantile haemangioma. The DFE-∂ gives a measure in dioptres, which may represent the true amblyopic risk, and so be useful in supporting treatment decisions in paediatric ophthalmology.

Iron from a submarine source impacts the productive layer of the Western Tropical South Pacific (WTSP).

PubMed

Guieu, Cécile; Bonnet, Sophie; Petrenko, Anne; Menkes, Christophe; Chavagnac, Valérie; Desboeufs, Karine; Maes, Christophe; Moutin, Thierry

2018-06-13

In the Western Tropical South Pacific, patches of high chlorophyll concentrations linked to the occurrence of N 2 -fixing organisms are found in the vicinity of volcanic islands. The survival of these organisms relies on a high bioavailable iron supply whose origin and fluxes remain unknown. Here, we measured high dissolved iron (DFe) concentrations (up to 66 nM) in the euphotic layer, extending zonally over 10 degrees longitude (174 E-175 W) at ∼20°S latitude. DFe atmospheric fluxes were at the lower end of reported values of the remote ocean and could not explain the high DFe concentrations measured in the water column in the vicinity of Tonga. We argue that the high DFe concentrations may be sustained by a submarine source, also characterized by freshwater input and recorded as salinity anomalies by Argo float in situ measurements and atlas data. The observed negative salinity anomalies are reproduced by simulations from a general ocean circulation model. Submarine iron sources reaching the euphotic layer may impact nitrogen fixation across the whole region.

The Distribution of Dissolved Iron in the West Atlantic Ocean

PubMed Central

Rijkenberg, Micha J. A.; Middag, Rob; Laan, Patrick; Gerringa, Loes J. A.; van Aken, Hendrik M.; Schoemann, Véronique; de Jong, Jeroen T. M.; de Baar, Hein J. W.

2014-01-01

Iron (Fe) is an essential trace element for marine life. Extremely low Fe concentrations limit primary production and nitrogen fixation in large parts of the oceans and consequently influence ocean ecosystem functioning. The importance of Fe for ocean ecosystems makes Fe one of the core chemical trace elements in the international GEOTRACES program. Despite the recognized importance of Fe, our present knowledge of its supply and biogeochemical cycle has been limited by mostly fragmentary datasets. Here, we present highly accurate dissolved Fe (DFe) values measured at an unprecedented high intensity (1407 samples) along the longest full ocean depth transect (17500 kilometers) covering the entire western Atlantic Ocean. DFe measurements along this transect unveiled details about the supply and cycling of Fe. External sources of Fe identified included off-shelf and river supply, hydrothermal vents and aeolian dust. Nevertheless, vertical processes such as the recycling of Fe resulting from the remineralization of sinking organic matter and the removal of Fe by scavenging still dominated the distribution of DFe. In the northern West Atlantic Ocean, Fe recycling and lateral transport from the eastern tropical North Atlantic Oxygen Minimum Zone (OMZ) dominated the DFe-distribution. Finally, our measurements showed that the North Atlantic Deep Water (NADW), the major driver of the so-called ocean conveyor belt, contains excess DFe relative to phosphate after full biological utilization and is therefore an important source of Fe for biological production in the global ocean. PMID:24978190

High Resolution Observations of Dissolved Iron Distribution Along a Coastal Offshore Transect in the Eastern North Atlantic.

NASA Astrophysics Data System (ADS)

Blain, S.; Laes, A.; Laan, P.; Achterberg, E.; de Baar, H.

2002-12-01

In order to better understand and quantify the inputs of iron from below in the water column a detailed section from the coast to offshore has been studied in the eastern North Atlantic. The section, extended from 47°36 58 N, 4°14 51 W (depth 96 m) to 46°00 00 N, 8°00 00 W (depth 4912 m). The cruise took place in March 2002, on board R/V Pelagia, as part of the European Union project IRONAGES. Fifteen stations have been sampled for dissolved iron (DFe) and nutrients analysis. Go Flo bottles mounted on a kevlar cable were used for clean seawater sampling in the water column. A torpedo fish and trace metal clean bellows pump were used for surface sampling. Sample were filtered on-line through an 0.2 μm cartridge. The DFe concentrations were measured onboard using a FIA method with on line preconcentration (8-HQ resin) and chemiluminescence detection (mean blank = 28 pM, mean limit of detection= 39 pM). The coastal stations over the shelf showed the highest concentrations of DFe. In this part of the transect, the concentration decreased from the surface to the bottom. Maxima (1-2.4 nM) were associated with increase in turbidity demonstrating the DFe inputs associated with re-suspended sediments and/or pore waters. In the eastern part of the transect, water of the Loire river has been identified has a source of iron. Close to the shelf break the two dimensional iron distribution became more complex. A tidal front, internal waves and slope currents created a patchy distribution of DFe. Evertheless the input from below was always observable at depth between 500 and 1200 m. Finally, in the western part of the transect, off the plateau, the concentration of DFe was strongly correlated with the occurrence of different water masses (see abstract by A. Laës).

Uptake and distribution of the abused inhalant 1,1-difluoroethane in the rat.

PubMed

Avella, Joseph; Kunaparaju, Naveen; Kumar, Sunil; Lehrer, Michael; Zito, S William; Barletta, Michael

2010-09-01

1,1-Difluoroethane (DFE) is a halogenated hydrocarbon used as a propellant in products designed for dusting electronic equipment and air brush painting. When abused, inhaled DFE produces intoxication and loss of muscular coordination. To investigate DFE toxicokinetics, groups (n = 3) of Sprague-Dawley rats were exposed to 30 s of 20 L/min DFE. The experimental model was designed to mimic exposure during abuse, a protocol which has not been conducted. Tissue collection (blood, brain, heart, liver, and kidney) occurred at 0, 10, 20, 30, 45, 60, 120, 240, 480, and 900 s. Average peak DFE levels were blood 352, brain 519, heart 338, liver 187, and kidney 364 mg/L or mg/kg. The total percent uptake of the administered dose was 4.0%. Uptake into individual compartments was 2.72, 0.38, 0.15, 0.41, and 0.32% for blood, brain, heart, liver, and kidney, respectively. All animals showed signs of intoxication within 20 s manifested as lethargy, prostration and loss of righting reflex. Marked intoxication continued for about 4 min when DFE averaged 21 mg/L in blood and 17 mg/kg in brain. Between 4 and 8 min, animals continued to show signs of sedation as evidenced by reduced aggression and excitement during handling. No discernable intoxication was evident after 8 min and blood and brain levels had fallen to 10 and 6 mg/L or kg, respectively. Plots of concentration (log) versus time were consistent with a two compartment model. Initial distribution was rapid with average half life (t((1/2))) during the alpha phase of 9 s for blood, 18 s for brain and 27 s in cardiac tissue. During beta slope elimination average t((1/2)) was 86 s in blood, 110 s in brain and 168 s in heart. Late elimination half lives were longer with blood gamma = 240 s, brain gamma = 340 s, and heart gamma = 231 s. Following acute exposure the Vd = 0.06 L, beta = 0.48 min(-1), AUC = 409.8 mg.min L(-1), and CL from blood was 0.03 L min(-1). The calculated toxicokinetic data may underestimate these parameters if DFE is abused chronically due to continued uptake into lowly perfused tissues with repeated dosing.

77 FR 16562 - Solicitation for a Cooperative Agreement-Curriculum Development for MET, ECCP, and ICMS Training...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-21

... designed to be delivered to staff at the SCA/DFE sites. The key elements from the ICMS approach that are... to design an MET approach appropriate for the SCA/DFE intervention which may differ from the... approaches, techniques, or design aspects proposed that will enhance the project? Organizational (35%) Does...

Adsorption induced modification of in-plane magnetic anisotropy in epitaxial Co and Fe/Co films on Fe(110)

NASA Astrophysics Data System (ADS)

Ślezak, M.; Ślezak, T.; Matlak, K.; DróŻdŻ, P.; Korecki, J.

2018-05-01

A study of in-plane magnetic anisotropy (MA) in epitaxial bcc Co films and Fe/Co bilayers on a Fe(110) surface is reported. Surface MA of as-deposited Co films and Fe/Co bilayers strongly depends on the Co (dCo) and Fe (dFe) thickness. Adsorption of residual gases drastically modifies in-plane MA of both Co films and Fe/Co bilayers. We present two dimensional MA maps in the (dCo, dFe) space for both as grown and adsorption-modified films. Our results indicate how to precisely engineer in-plane MA that can be controlled by dCo, dFe and is sensitive to the residual gas adsorption.

Behavioral assessment of adaptive feedback equalization in a digital hearing aid.

PubMed

French-St George, M; Wood, D J; Engebretson, A M

1993-01-01

An evaluation was made of the efficacy of a digital feedback equalization algorithm employed by the Central Institute for the Deaf Wearable Adaptive Digital Hearing Aid. Three questions were addressed: 1) Does acoustic feedback limit gain adjustments made by hearing aid users? 2) Does feedback equalization permit users with hearing-impairment to select more gain without feedback? and, 3) If more gain is used when feedback equalization is active, does word identification performance improve? Nine subjects with hearing impairment participated in the study. Results suggest that listeners with hearing impairment are indeed limited by acoustic feedback when listening to soft speech (55 dB A) in quiet. The average listener used an additional 4 dB gain when feedback equalization was active. This additional gain resulted in an average 10 rationalized arcsine units (RAU) improvement in word identification score.

Temporal variability of dissolved iron species in the mesopelagic zone at Ocean Station PAPA

NASA Astrophysics Data System (ADS)

Schallenberg, Christina; Ross, Andrew R. S.; Davidson, Ashley B.; Stewart, Gillian M.; Cullen, Jay T.

2017-08-01

Deposition of atmospheric aerosols to the surface ocean is considered an important mechanism for the supply of iron (Fe) to remote ocean regions, but direct observations of the oceanic response to aerosol deposition are sparse. In the high nutrient, low chlorophyll (HNLC) subarctic Pacific Ocean we observed a dissolved Fe and Fe(II) anomaly at depth that is best explained as the result of aerosol deposition from Siberian forest fires in May 2012. Interestingly, there was no evidence of enhanced dFe concentrations in surface waters, nor was there a detectable phytoplankton bloom in response to the suspected aerosol deposition. Dissolved Fe (dFe) and Fe(II) showed the strongest enhancement in the subsurface oxygen deficient zone (ODZ), where oxygen concentrations <50 μmol kg-1 are prevalent. In the upper 200 m, dFe concentrations were at or below historic background levels, consistent with a short residence time of aerosol particles in surface waters and possible scavenging loss of dFe. Aerosol toxicity and/or dominance of particle scavenging over dissolution of Fe in the upper water column may have contributed to the lack of a strong phytoplankton response.

Seasonal and spatial variabilities in northern Gulf of Alaska surface water iron concentrations driven by shelf sediment resuspension, glacial meltwater, a Yakutat eddy, and dust

NASA Astrophysics Data System (ADS)

Crusius, John; Schroth, Andrew W.; Resing, Joseph A.; Cullen, Jay; Campbell, Robert W.

2017-06-01

Phytoplankton growth in the Gulf of Alaska (GoA) is limited by iron (Fe), yet Fe sources are poorly constrained. We examine the temporal and spatial distributions of Fe, and its sources in the GoA, based on data from three cruises carried out in 2010 from the Copper River (AK) mouth to beyond the shelf break. April data are the first to describe late winter Fe behavior before surface water nitrate depletion began. Sediment resuspension during winter and spring storms generated high "total dissolvable Fe" (TDFe) concentrations of 1000 nmol kg-1 along the entire continental shelf, which decreased beyond the shelf break. In July, high TDFe concentrations were similar on the shelf, but more spatially variable, and driven by low-salinity glacial meltwater. Conversely, dissolved Fe (DFe) concentrations in surface waters were far lower and more seasonally consistent, ranging from 4 nmol kg-1 in nearshore waters to 0.6-1.5 nmol kg-1 seaward of the shelf break during April and July, despite dramatic depletion of nitrate over that period. The reasonably constant DFe concentrations are likely maintained during the year across the shelf by complexation by strong organic ligands, coupled with ample supply of labile particulate Fe. The April DFe data can be simulated using a simple numerical model that assumes a DFe flux from shelf sediments, horizontal transport by eddy diffusion, and removal by scavenging. Given how global change is altering many processes impacting the Fe cycle, additional studies are needed to examine controls on DFe in the Gulf of Alaska.

A normative inference approach for optimal sample sizes in decisions from experience

PubMed Central

Ostwald, Dirk; Starke, Ludger; Hertwig, Ralph

2015-01-01

“Decisions from experience” (DFE) refers to a body of work that emerged in research on behavioral decision making over the last decade. One of the major experimental paradigms employed to study experience-based choice is the “sampling paradigm,” which serves as a model of decision making under limited knowledge about the statistical structure of the world. In this paradigm respondents are presented with two payoff distributions, which, in contrast to standard approaches in behavioral economics, are specified not in terms of explicit outcome-probability information, but by the opportunity to sample outcomes from each distribution without economic consequences. Participants are encouraged to explore the distributions until they feel confident enough to decide from which they would prefer to draw from in a final trial involving real monetary payoffs. One commonly employed measure to characterize the behavior of participants in the sampling paradigm is the sample size, that is, the number of outcome draws which participants choose to obtain from each distribution prior to terminating sampling. A natural question that arises in this context concerns the “optimal” sample size, which could be used as a normative benchmark to evaluate human sampling behavior in DFE. In this theoretical study, we relate the DFE sampling paradigm to the classical statistical decision theoretic literature and, under a probabilistic inference assumption, evaluate optimal sample sizes for DFE. In our treatment we go beyond analytically established results by showing how the classical statistical decision theoretic framework can be used to derive optimal sample sizes under arbitrary, but numerically evaluable, constraints. Finally, we critically evaluate the value of deriving optimal sample sizes under this framework as testable predictions for the experimental study of sampling behavior in DFE. PMID:26441720

"It's All about Developing the Whole Child": An Examination of the "Legacy" Benefits of Youth Sport Trust's School-Based Inclusion Initiatives

ERIC Educational Resources Information Center

Black, Alison; Costello, Rebecca; Craft, Anna; Katene, Will

2015-01-01

Between 2011 and 2013, the Department for Education (DfE) in England made £3.3 million available to support the development of opportunities for young disabled people to access high-quality physical education and school sport. The DfE with the Youth Sport Trust (YST) developed a range of initiatives to help meet this aim, including Project…

Iron Biogeochemistry in the High Latitude North Atlantic Ocean.

PubMed

Achterberg, Eric P; Steigenberger, Sebastian; Marsay, Chris M; LeMoigne, Frédéric A C; Painter, Stuart C; Baker, Alex R; Connelly, Douglas P; Moore, C Mark; Tagliabue, Alessandro; Tanhua, Toste

2018-01-19

Iron (Fe) is an essential micronutrient for marine microbial organisms, and low supply controls productivity in large parts of the world's ocean. The high latitude North Atlantic is seasonally Fe limited, but Fe distributions and source strengths are poorly constrained. Surface ocean dissolved Fe (DFe) concentrations were low in the study region (<0.1 nM) in summer 2010, with significant perturbations during spring 2010 in the Iceland Basin as a result of an eruption of the Eyjafjallajökull volcano (up to 2.5 nM DFe near Iceland) with biogeochemical consequences. Deep water concentrations in the vicinity of the Reykjanes Ridge system were influenced by pronounced sediment resuspension, with indications for additional inputs by hydrothermal vents, with subsequent lateral transport of Fe and manganese plumes of up to 250-300 km. Particulate Fe formed the dominant pool, as evidenced by 4-17 fold higher total dissolvable Fe compared with DFe concentrations, and a dynamic exchange between the fractions appeared to buffer deep water DFe. Here we show that Fe supply associated with deep winter mixing (up to 103 nmol m -2 d -1 ) was at least ca. 4-10 times higher than atmospheric deposition, diffusive fluxes at the base of the summer mixed layer, and horizontal surface ocean fluxes.

Free-space optics mode-wavelength division multiplexing system using LG modes based on decision feedback equalization

NASA Astrophysics Data System (ADS)

Amphawan, Angela; Ghazi, Alaan; Al-dawoodi, Aras

2017-11-01

A free-space optics mode-wavelength division multiplexing (MWDM) system using Laguerre-Gaussian (LG) modes is designed using decision feedback equalization for controlling mode coupling and combating inter symbol interference so as to increase channel diversity. In this paper, a data rate of 24 Gbps is achieved for a FSO MWDM channel of 2.6 km in length using feedback equalization. Simulation results show significant improvement in eye diagrams and bit-error rates before and after decision feedback equalization.

Experimental Results and Issues on Equalization for Nonlinear Memory Channel: Pre-Cursor Enhanced Ram-DFE Canceler

NASA Technical Reports Server (NTRS)

Yuan, Lu; LeBlanc, James

1998-01-01

This thesis investigates the effects of the High Power Amplifier (HPA) and the filters over a satellite or telemetry channel. The Volterra series expression is presented for the nonlinear channel with memory, and the algorithm is based on the finite-state machine model. A RAM-based algorithm operating on the receiver side, Pre-cursor Enhanced RAM-FSE Canceler (PERC) is developed. A high order modulation scheme , 16-QAM is used for simulation, the results show that PERC provides an efficient and reliable method to transmit data on the bandlimited nonlinear channel. The contribution of PERC algorithm is that it includes both pre-cursors and post-cursors as the RAM address lines, and suggests a new way to make decision on the pre-addresses. Compared with the RAM-DFE structure that only includes post- addresses, the BER versus Eb/NO performance of PERC is substantially enhanced. Experiments are performed for PERC algorithms with different parameters on AWGN channels, and the results are compared and analyzed. The investigation of this thesis includes software simulation and hardware verification. Hardware is setup to collect actual TWT data. Simulation on both the software-generated data and the real-world data are performed. Practical limitations are considered for the hardware collected data. Simulation results verified the reliability of the PERC algorithm. This work was conducted at NMSU in the Center for Space Telemetering and Telecommunications Systems in the Klipsch School of Electrical and Computer Engineering Department.

Triggered Seismicity in Utah from the November 3, 2002, Denali Fault Earthquake

NASA Astrophysics Data System (ADS)

Pankow, K. L.; Nava, S. J.; Pechmann, J. C.; Arabasz, W. J.

2002-12-01

Coincident with the arrival of the surface waves from the November 3, 2002, Mw 7.9 Denali Fault, Alaska earthquake (DFE), the University of Utah Seismograph Stations (UUSS) regional seismic network detected a marked increase in seismicity along the Intermountain Seismic Belt (ISB) in central and north-central Utah. The number of earthquakes per day in Utah located automatically by the UUSS's Earthworm system in the week following the DFE was approximately double the long-term average during the preceding nine months. From these preliminary data, the increased seismicity appears to be characterized by small magnitude events (M = 3.2) and concentrated in five distinct spatial clusters within the ISB between 38.75°and 42.0° N. The first of these earthquakes was an M 2.2 event located ~20 km east of Salt Lake City, Utah, which occurred during the arrival of the Love waves from the DFE. The increase in Utah earthquake activity at the time of the arrival of the surface waves from the DFE suggests that these surface waves triggered earthquakes in Utah at distances of more than 3,000 km from the source. We estimated the peak dynamic shear stress caused by these surface waves from measurements of their peak vector velocities at 43 recording sites: 37 strong-motion stations of the Advanced National Seismic System and six broadband stations. (The records from six other broadband instruments in the region of interest were clipped.) The estimated peak stresses ranged from 1.2 bars to 3.5 bars with a mean of 2.3 bars, and generally occurred during the arrival of Love waves of ~15 sec period. These peak dynamic shear stress estimates are comparable to those obtained from recordings of the 1992 Mw 7.3 Landers, California, earthquake in regions where the Landers earthquake triggered increased seismicity. We plan to present more complete analyses of UUSS seismic network data, further testing our hypothesis that the DFE remotely triggered seismicity in Utah. This hypothesis is important to investigate because well-documented evidence for triggering of seismicity by distant earthquakes comes primarily from areas characterized by recent volcanic or geothermal activity. The regions of apparent triggered seismicity from the DFE in Utah fall into neither of these two categories.

Thermal and ion-induced surface reactions of 1,1-difluoroethylene on Si(111)7 x 7 and vitreous SiO2.

PubMed

He, Zhenhua; Leung, K T

2005-08-11

Thermal and ion-induced reactions of 1,1-difluoroethylene (1,1-C2H2F2 or iso-DFE) on Si(111)7 x 7 and vitreous SiO2 surfaces have been investigated by vibrational electron energy loss spectroscopy and thermal desorption spectrometry. Like ethylene, iso-DFE predominantly chemisorbs via a [2 + 2] cycloaddition mechanism onto the 7 x 7 surface as a di-sigma-bonded difluoroethane-1,2-diyl adstructure, which undergoes H abstraction and defluorination, producing hydrocarbon fragments and SiF(x) (x = 1-3) upon annealing to >700 K. Ion irradiation of Si(111)7 x 7 in iso-DFE at 50 eV impact energy appears to substantially enhance the production of hydrocarbon fragments and SiF(x)(), leading to stronger SiF4 desorption products over an extended temperature range (400-900 K). The observed SiC and SiF(x) produced on the 7 x 7 surface by ion irradiation in iso-DFE are found to be similar to those obtained by ion irradiation in the fluoromethane homologues, CF4 and CH2F2. The production of higher relative concentrations for the larger SiF(x) and C2-containing fragments is evidently favored on the 7 x 7 surface. On a vitreous SiO2 surface, ion irradiation in iso-DFE, unlike that in CF4 and CH2F2, appears to produce less SiF(x) than that on the 7 x 7 surface, which indicates that surface O does not interact strongly with the C2-containing fragments. The presence or absence of a C=C bond and the relative F-to-C ratio of the sputtering gas could therefore produce important effects on the resulting surface products obtained by low-energy ion irradiation.

High-accuracy determination of iron in seawater by isotope dilution multiple collector inductively coupled plasma mass spectrometry (ID-MC-ICP-MS) using nitrilotriacetic acid chelating resin for pre-concentration and matrix separation.

PubMed

de Jong, Jeroen; Schoemann, Véronique; Lannuzel, Delphine; Tison, Jean-Louis; Mattielli, Nadine

2008-08-15

In the present paper we describe a robust and simple method to measure dissolved iron (DFe) concentrations in seawater down to <0.1 nmol L(-1) level, by isotope dilution multiple collector inductively coupled plasma mass spectrometry (ID-MC-ICP-MS) using a (54)Fe spike and measuring the (57)Fe/(54)Fe ratio. The method provides for a pre-concentration step (100:1) by micro-columns filled with the resin NTA Superflow of 50 mL seawater samples acidified to pH 1.9. NTA Superflow is demonstrated to quantitatively extract Fe from acidified seawater samples at this pH. Blanks are kept low (grand mean 0.045+/-0.020 nmol L(-1), n=21, 3 x S.D. limit of detection per session 0.020-0.069 nmol L(-1) range), as no buffer is required to adjust the sample pH for optimal extraction, and no other reagents are needed than ultrapure nitric acid, 12 mM H(2)O(2), and acidified (pH 1.9) ultra-high purity (UHP) water. We measured SAFe (sampling and analysis of Fe) reference seawater samples Surface-1 (0.097+/-0.043 nmol L(-1)) and Deep-2 (0.91+/-0.17 nmol L(-1)) and obtained results that were in excellent agreement with their DFe consensus values: 0.118+/-0.028 nmol L(-1) (n=7) for Surface-1 and 0.932+/-0.059 nmol L(-1) (n=9) for Deep-2. We also present a vertical DFe profile from the western Weddell Sea collected during the Ice Station Polarstern (ISPOL) ice drift experiment (ANT XXII-2, RV Polarstern) in November 2004-January 2005. The profile shows near-surface DFe concentrations of approximately 0.6 nmol L(-1) and bottom water enrichment up to 23 nmol L(-1) DFe.

Theobroma cacao extract attenuates the development of Dermatophagoides farinae-induced atopic dermatitis-like symptoms in NC/Nga mice.

PubMed

Kang, Heerim; Lee, Chang Hyung; Kim, Jong Rhan; Kwon, Jung Yeon; Son, Myoung-Jin; Kim, Jong-Eun; Lee, Ki Won

2017-02-01

Cacao beans from Theobroma cacao are an abundant source of polyphenols, particularly flavonoids. Previous studies demonstrated that cacao flavanols decrease pro-inflammatory cytokines resulting in the alleviation of allergic symptoms. We sought to investigate the effects of cacao extract (CE) on Dermatophagoides farinae extract (DFE)-induced atopic dermatitis (AD)-like symptoms. CE attenuated DFE-induced AD-like symptoms as assessed by skin lesion analyses, dermatitis score, and skin thickness. Histopathological analysis revealed that CE suppressed DFE-induced immune cell infiltration into the skin. These observations occurred concomitantly with the downregulation of inflammatory markers including serum immunoglobulin (Ig) E, chemokine; thymus and activation-regulated chemokine and macrophage-derived chemokine as well as the skin-derived cytokines interleukin (IL)-4, IL-5, and interferon-γ. CE also significantly alleviated transepidermal water loss and increased skin hydration. These results suggest that CE, a natural phytochemical-rich food, has potential therapeutic efficacy for the treatment of AD. Copyright © 2016. Published by Elsevier Ltd.

Iron Supply and Demand in an Antarctic Shelf Ecosystem

NASA Astrophysics Data System (ADS)

McGillicuddy, D. J., Jr.; Sedwick, P.; Dinniman, M. S.; Arrigo, K. R.; Bibby, T. S.; Greenan, B. J. W.; Hofmann, E. E.; Klinck, J. M., II; Smith, W.; Mack, S. L.; Marsay, C. M.; Sohst, B. M.; van Dijken, G.

2016-02-01

The Ross Sea sustains a rich ecosystem and is the most productive sector of the Southern Ocean. Most of this production occurs within a polynya during the November-February period, when the availability of dissolved iron (dFe) is thought to exert the major control on phytoplankton growth. Here we combine new data on the distribution of dFe, high-resolution model simulations of ice melt and regional circulation, and satellite-based estimates of primary production to quantify iron supply and demand over the Ross Sea continental shelf. Our analysis suggests that the largest sources of dFe to the euphotic zone are wintertime mixing and melting sea ice, with a lesser input from intrusions of Circumpolar Deep Water, and a small amount from melting glacial ice. Together these sources are in approximate balance with the annual biological dFe demand inferred from satellite-based productivity algorithms, although both the supply and demand estimates have large uncertainties. Our findings illustrate the complexities of iron cycling in the Southern Ocean, highlighting the heterogeneity of the underlying processes along the Antarctic continental margin. Explicit representation of these complexities, and the temporal variability in both proximate and ultimate sources of iron, will be necessary to understand how a changing climate will affect this important ecosystem and its influence on biogeochemical cycles. Reduction of the present uncertainties in iron supply and demand will require coupled observational and modeling systems capable of resolving the wide range of physical, biological, and chemical processes involved.

"3D fusion" echocardiography improves 3D left ventricular assessment: comparison with 2D contrast echocardiography.

PubMed

Augustine, Daniel; Yaqub, Mohammad; Szmigielski, Cezary; Lima, Eduardo; Petersen, Steffen E; Becher, Harald; Noble, J Alison; Leeson, Paul

2015-02-01

Three-dimensional fusion echocardiography (3DFE) is a novel postprocessing approach that utilizes imaging data acquired from multiple 3D acquisitions. We assessed image quality, endocardial border definition, and cardiac wall motion in patients using 3DFE compared to standard 3D images (3D) and results obtained with contrast echocardiography (2DC). Twenty-four patients (mean age 66.9 ± 13 years, 17 males, 7 females) undergoing 2DC had three, noncontrast, 3D apical volumes acquired at rest. Images were fused using an automated image fusion approach. Quality of the 3DFE was compared to both 3D and 2DC based on contrast-to-noise ratio (CNR) and endocardial border definition. We then compared clinical wall-motion score index (WMSI) calculated from 3DFE and 3D to those obtained from 2DC images. Fused 3D volumes had significantly improved CNR (8.92 ± 1.35 vs. 6.59 ± 1.19, P < 0.0005) and segmental image quality (2.42 ± 0.99 vs. 1.93 ± 1.18, P < 0.005) compared to unfused 3D acquisitions. Levels achieved were closer to scores for 2D contrast images (CNR: 9.04 ± 2.21, P = 0.6; segmental image quality: 2.91 ± 0.37, P < 0.005). WMSI calculated from fused 3D volumes did not differ significantly from those obtained from 2D contrast echocardiography (1.06 ± 0.09 vs. 1.07 ± 0.15, P = 0.69), whereas unfused images produced significantly more variable results (1.19 ± 0.30). This was confirmed by a better intraclass correlation coefficient (ICC 0.72; 95% CI 0.32-0.88) relative to comparisons with unfused images (ICC 0.56; 95% CI 0.02-0.81). 3DFE significantly improves left ventricular image quality compared to unfused 3D in a patient population and allows noncontrast assessment of wall motion that approaches that achieved with 2D contrast echocardiography. © 2014, Wiley Periodicals, Inc.

Solvent organization around the perfluoro group of coumarin 153 governs its photophysical properties: An experimental and simulation study of coumarin dyes in ethanol as well as fluorinated ethanol solvents.

PubMed

Mondal, Saptarsi; Halder, Ritaban; Biswas, Biswajit; Jana, Biman; Singh, Prashant Chandra

2016-05-14

The self-aggregation property of the perfluoro group containing molecules makes it important in the research fields of biology and polymer and organic synthesis. In the quest of understanding the role of the perfluoro group on the photophysical properties of perfluoro-containing molecules in biologically important fluoroethanol solvents, we have applied photophysical as well as molecular dynamics simulation techniques to explore the properties of perfluoro groups containing molecule coumarin-153 (C153) in ethanol (ETH), monofluoroethanol (MFE), difluoroethanol (DFE), and trifluoroethanol (TFE) and compared them with the molecules without perfluoro moiety, namely coumarin-6H (C6H) and coumarin-480 (C480). In contrast to C6H and C480, the excited state lifetime of C153 in fluorinated ETHs is not monotonic. The excited state lifetime of C153 decreases in MFE and DFE as compared to ETH, whereas in TFE, it increases as compared to MFE and DFE. Molecular dynamics simulation reveals that the carbon terminal away from the OH group of fluorinated ETHs has a preferential orientation near the perfluoro (CF3) group of C153. In MFE and DFE, the CF3 group of C153 prefers to have a CF2-F⋯H -(CHF) type of electrostatic interaction over CF2-F⋯F -(CH2) kind of dispersion interaction which increases the rate of nonradiative decay, probably due to the electrostatic nature of the CF2-F⋯H -(CHF) hydrogen bond. On the other hand, in TFE, C-F⋯ F-C type of dispersion interaction, also known as fluorous interaction, takes place between the CF3 groups of C153 and TFE which decreases the rate of nonradiative rate as compared to MFE and DFE, leading to the increased lifetime of C153 in TFE. Photophysical and MD simulation studies clearly depict that the structural organization of solvents and their interaction with the fluorocarbon group are crucial factors for the photophysical behavior of the fluorocarbon containing molecules.

Solvent organization around the perfluoro group of coumarin 153 governs its photophysical properties: An experimental and simulation study of coumarin dyes in ethanol as well as fluorinated ethanol solvents

NASA Astrophysics Data System (ADS)

Mondal, Saptarsi; Halder, Ritaban; Biswas, Biswajit; Jana, Biman; Singh, Prashant Chandra

2016-05-01

The self-aggregation property of the perfluoro group containing molecules makes it important in the research fields of biology and polymer and organic synthesis. In the quest of understanding the role of the perfluoro group on the photophysical properties of perfluoro-containing molecules in biologically important fluoroethanol solvents, we have applied photophysical as well as molecular dynamics simulation techniques to explore the properties of perfluoro groups containing molecule coumarin-153 (C153) in ethanol (ETH), monofluoroethanol (MFE), difluoroethanol (DFE), and trifluoroethanol (TFE) and compared them with the molecules without perfluoro moiety, namely coumarin-6H (C6H) and coumarin-480 (C480). In contrast to C6H and C480, the excited state lifetime of C153 in fluorinated ETHs is not monotonic. The excited state lifetime of C153 decreases in MFE and DFE as compared to ETH, whereas in TFE, it increases as compared to MFE and DFE. Molecular dynamics simulation reveals that the carbon terminal away from the OH group of fluorinated ETHs has a preferential orientation near the perfluoro (CF3) group of C153. In MFE and DFE, the CF3 group of C153 prefers to have a CF2—F⋯H —(CHF) type of electrostatic interaction over CF2—F⋯F —(CH2) kind of dispersion interaction which increases the rate of nonradiative decay, probably due to the electrostatic nature of the CF2—F⋯H —(CHF) hydrogen bond. On the other hand, in TFE, C—F⋯ F—C type of dispersion interaction, also known as fluorous interaction, takes place between the CF3 groups of C153 and TFE which decreases the rate of nonradiative rate as compared to MFE and DFE, leading to the increased lifetime of C153 in TFE. Photophysical and MD simulation studies clearly depict that the structural organization of solvents and their interaction with the fluorocarbon group are crucial factors for the photophysical behavior of the fluorocarbon containing molecules.

Properties of an adaptive feedback equalization algorithm.

PubMed

Engebretson, A M; French-St George, M

1993-01-01

This paper describes a new approach to feedback equalization for hearing aids. The method involves the use of an adaptive algorithm that estimates and tracks the characteristic of the hearing aid feedback path. The algorithm is described and the results of simulation studies and bench testing are presented.

Immunopotentiator from Pantoea agglomerans Prevents Atopic Dermatitis Induced by Dermatophagoides farinae Extract in NC/Nga Mouse.

PubMed

Wakame, Koji; Komatsu, Ken-Ichi; Inagawa, Hiroyuki; Nishizawa, Takashi

2015-08-01

Pantoea agglomerans LPS (immunopotentiator from Pantoea agglomerans 1: IP-PA1) has been reported to have anti-inflammatory effects in in vitro and in vivo models. The aim of the present study was to investigate the effects of orally-administered IP-PA1 on atopic dermatitis (AD) symptoms induced by Dermatophagoides farinae body extract (DFE) in NC/Nga mice. Using the NC/Nga AD murine model, mice were orally administered 0.1% (High) or 0.01% (Low) water-containing IP-PA1. Skin lesion assessment and blood collection from the caudal vein was performed on days 0, 7, 21 and 31. On day 31, all mice were sacrificed and blood, skin, spleen, as well as intestine samples, were obtained. Assessment score of the skin lesion and serum immunoglobulin E (IgE) level of both IP-PA1 groups were significantly lower than that of the DFE group on days 14 and 21. The serum periostin and thymus and activation-regulated chemokine (TARC) level of IP-PA1-Low group was significantly lower than that of the DFE group on day 31. On histological examination of the skin, hyperplasia of epidermal and dermal layers and infiltration of inflammatory cells were suppressed by IP-PA1 administration. Deposition of periostin was observed in the DFE group skin tissue. Moreover, the CD4(+)/CD8(+) ratio of splenic T-cells increased by IP-PA1 administration. IP-PA1 administration may have an inhibitory effect on AD skin lesions. Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Characterizability of metabolic pathway systems from time series data.

PubMed

Voit, Eberhard O

2013-12-01

Over the past decade, the biomathematical community has devoted substantial effort to the complicated challenge of estimating parameter values for biological systems models. An even more difficult issue is the characterization of functional forms for the processes that govern these systems. Most parameter estimation approaches tacitly assume that these forms are known or can be assumed with some validity. However, this assumption is not always true. The recently proposed method of Dynamic Flux Estimation (DFE) addresses this problem in a genuinely novel fashion for metabolic pathway systems. Specifically, DFE allows the characterization of fluxes within such systems through an analysis of metabolic time series data. Its main drawback is the fact that DFE can only directly be applied if the pathway system contains as many metabolites as unknown fluxes. This situation is unfortunately rare. To overcome this roadblock, earlier work in this field had proposed strategies for augmenting the set of unknown fluxes with independent kinetic information, which however is not always available. Employing Moore-Penrose pseudo-inverse methods of linear algebra, the present article discusses an approach for characterizing fluxes from metabolic time series data that is applicable even if the pathway system is underdetermined and contains more fluxes than metabolites. Intriguingly, this approach is independent of a specific modeling framework and unaffected by noise in the experimental time series data. The results reveal whether any fluxes may be characterized and, if so, which subset is characterizable. They also help with the identification of fluxes that, if they could be determined independently, would allow the application of DFE. Copyright © 2013 Elsevier Inc. All rights reserved.

Characterizability of Metabolic Pathway Systems from Time Series Data

PubMed Central

Voit, Eberhard O.

2013-01-01

Over the past decade, the biomathematical community has devoted substantial effort to the complicated challenge of estimating parameter values for biological systems models. An even more difficult issue is the characterization of functional forms for the processes that govern these systems. Most parameter estimation approaches tacitly assume that these forms are known or can be assumed with some validity. However, this assumption is not always true. The recently proposed method of Dynamic Flux Estimation (DFE) addresses this problem in a genuinely novel fashion for metabolic pathway systems. Specifically, DFE allows the characterization of fluxes within such systems through an analysis of metabolic time series data. Its main drawback is the fact that DFE can only directly be applied if the pathway system contains as many metabolites as unknown fluxes. This situation is unfortunately rare. To overcome this roadblock, earlier work in this field had proposed strategies for augmenting the set of unknown fluxes with independent kinetic information, which however is not always available. Employing Moore-Penrose pseudo-inverse methods of linear algebra, the present article discusses an approach for characterizing fluxes from metabolic time series data that is applicable even if the pathway system is underdetermined and contains more fluxes than metabolites. Intriguingly, this approach is independent of a specific modeling framework and unaffected by noise in the experimental time series data. The results reveal whether any fluxes may be characterized and, if so, which subset is characterizable. They also help with the identification of fluxes that, if they could be determined independently, would allow the application of DFE. PMID:23391489

High resolution spectroscopy of 1,2-difluoroethane in a molecular beam: A case study of vibrational mode-coupling

NASA Astrophysics Data System (ADS)

Mork, Steven W.; Miller, C. Cameron; Philips, Laura A.

1992-09-01

The high resolution infrared spectrum of 1,2-difluoroethane (DFE) in a molecular beam has been obtained over the 2978-2996 cm-1 spectral region. This region corresponds to the symmetric combination of asymmetric C-H stretches in DFE. Observed rotational fine structure indicates that this C-H stretch is undergoing vibrational mode coupling to a single dark mode. The dark mode is split by approximately 19 cm-1 due to tunneling between the two identical gauche conformers. The mechanism of the coupling is largely anharmonic with a minor component of B/C plane Coriolis coupling. Effects of centrifugal distortion along the molecular A-axis are also observed. Analysis of the fine structure identifies the dark state as being composed of C-C torsion, CCF bend, and CH2 rock. Coupling between the C-H stretches and the C-C torsion is of particular interest because DFE has been observed to undergo vibrationally induced isomerization from the gauche to trans conformer upon excitation of the C-H stretch.

Cardiomyopathy from 1,1-Difluoroethane Inhalation.

PubMed

Kumar, Suwen; Joginpally, Tejaswini; Kim, David; Yadava, Mrinal; Norgais, Konchok; Laird-Fick, Heather S

2016-10-01

Consumer aerosol products can be inhaled for their psychoactive effects, but with attendant adverse health effects including "sudden sniffing death." Cardiomyopathy has rarely been described in association with 1,1-difluoroethane (DFE), a common aerosol propellant. We report a 33-year-old male who developed acute myocardial injury and global hypokinesis along with rhabdomyolysis, acute kidney injury, and fulminant hepatitis after 2 days' nearly continuous huffing. Workup for other causes, including underlying coronary artery disease, was negative. His cardiac function improved over time. The exact mechanism of DFE's effects is uncertain but may include catecholamine-induced cardiomyopathy, coronary vasospasm, or direct cellular toxicity.

Application of neural network in the study of combustion rate of natural gas/diesel dual fuel engine.

PubMed

Yan, Zhao-Da; Zhou, Chong-Guang; Su, Shi-Chuan; Liu, Zhen-Tao; Wang, Xi-Zhen

2003-01-01

In order to predict and improve the performance of natural gas/diesel dual fuel engine (DFE), a combustion rate model based on forward neural network was built to study the combustion process of the DFE. The effect of the operating parameters on combustion rate was also studied by means of this model. The study showed that the predicted results were good agreement with the experimental data. It was proved that the developed combustion rate model could be used to successfully predict and optimize the combustion process of dual fuel engine.

Influence of different acid and alkaline cleaning agents on the effects of irrigation of synthetic dairy factory effluent on soil quality, ryegrass growth and nutrient uptake.

PubMed

Liu, Y-Y; Haynes, R J

2013-01-01

The aim of this study was to examine the effects of replacement of phosphoric acid with nitric or acetic acid, and replacement of NaOH with KOH, as cleaning agents in dairy factories, on the effects that irrigation of dairy factory effluent (DFE) has on the soil-plant system. A 16-week greenhouse study was carried out in which the effects of addition of synthetic dairy factory effluent containing (a) milk residues alone or milk residues plus (b) H(3)PO(4)/NaOH, (c) H(3)PO(4)/HNO(3)/NaOH or (d) CH(3)COOH/KOH, on soil's chemical, physical and microbial properties and perennial ryegrass growth and nutrient uptake were investigated. The cumulative effect of DFE addition was to increase exchangeable Na, K, Ca, Mg, exchangeable sodium percentage, microbial biomass C and N and basal respiration in the soil. Dry matter yields of ryegrass were increased by additions of DFE other than that containing CH(3)COOH. Plant uptake of P, Ca and Mg was in the same order as their inputs in DFE but for Na; inputs were an order of magnitude greater than plant uptake. Replacement of NaOH by KOH resulted in increased accumulation of exchangeable K. The effects of added NaOH and KOH on promoting breakdown of soil aggregates during wet sieving (and formation of a < 0.25 mm size class) were similar. Replacement of H(2)PO(4) by HNO(3) is a viable but CH(3)COOH appears to have detrimental effects on plant growth. Replacement of NaOH by KOH lowers the likelihood of phytotoxic effects of Na, but K and Na have similar effects on disaggregation.

Time-dependent progression from the acute to chronic phases in atopic dermatitis induced by epicutaneous allergen stimulation in NC/Nga mice.

PubMed

Kim, Ji-Yun; Jeong, Mi Sook; Park, Mi Kyung; Lee, Mi-Kyung; Seo, Seong Jun

2014-01-01

Atopic dermatitis (AD) is a complicated skin condition influenced by genetic background and environmental factors. In this study, we applied Dermatophagoides farinae body extract (DfE) to the barrier-disrupted skin of NC/Nga mice twice a week for 8 weeks to identify the clinical and immunological factors in AD progression. Repeated application of the DfE to the skin of NC/Nga mice showed the similar consequences for the natural course of progression in human AD, histologically and immunologically. We confirmed that the AD-like skin lesions in NC/Nga mice did not last for the whole period of our experiment in spite of repeated topical applications of DfE twice a week. Topical DfE stimulation increased the skin mRNA expressions of Th1-, Th2- and Th17-related cytokines in the acute phase. The expression patterns of IL-4 and IL-13 in splenic T cells and skin lesions were consistent with the time course alterations of clinical features of AD-like skin symptoms. We also showed that there was a remission phase either just before or right after the chronic phase in this experimental model. Interestingly, splenic T-cell-derived IL-5 expression began to increase in the chronic phase, while skin-derived IL-5 mRNA expression increased in the acute phase. In conclusion, our results suggest that we should pay attention to the characteristics of each stage of AD progression and choose a suitable corresponding stage of animal model not only to elucidate the pathogenesis of AD but also to develop and evaluate therapeutic drugs for AD. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Accumulation of Fe oxyhydroxides in the Peruvian oxygen deficient zone implies non-oxygen dependent Fe oxidation

DOE PAGES

Heller, Maija I.; Lam, Phoebe J.; Moffett, James W.; ...

2017-05-19

Oxygen minimum zones (OMZs) have been proposed to be an important source of dissolved iron (Fe) into the interior ocean. However, previous studies in OMZs have shown a sharp decrease in total dissolved Fe (dFe) and/or dissolved Fe(II) (dFe(II)) concentrations at the shelf-break, despite constant temperature, salinity and continued lack of oxygen across the shelf-break. The loss of both total dFe and dFe(II) suggests a conversion of the dFe to particulate form, but studies that have coupled the reduction-oxidation (redox) speciation of both dissolved and particulate phases have not previously been done. Here in this work, we have measured themore » redox speciation and concentrations of both dissolved and particulate forms of Fe in samples collected during the U.S. GEOTRACES Eastern tropical Pacific Zonal Transect (EPZT) cruise in 2013 (GP16). This complete data set allows us to assess possible mechanisms for loss of dFe. We observed an offshore loss of dFe(II) within the oxygen deficient zone (ODZ), where dissolved oxygen is undetectable, accompanied by an increase in total particulate Fe (pFe). Total pFe concentrations were highest in the upper ODZ. X-ray absorption spectroscopy revealed that the pFe maximum was primarily in the Fe(III) form as Fe(III) oxyhydroxides. The remarkable similarity in the distributions of total particulate iron and nitrite suggests a role for nitrite in the oxidation of dFe(II) to pFe(III). Lastly, we present a conceptual model for the rapid redox cycling of Fe that occurs in ODZs, despite the absence of oxygen.« less

Accumulation of Fe oxyhydroxides in the Peruvian oxygen deficient zone implies non-oxygen dependent Fe oxidation

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

Heller, Maija I.; Lam, Phoebe J.; Moffett, James W.

Oxygen minimum zones (OMZs) have been proposed to be an important source of dissolved iron (Fe) into the interior ocean. However, previous studies in OMZs have shown a sharp decrease in total dissolved Fe (dFe) and/or dissolved Fe(II) (dFe(II)) concentrations at the shelf-break, despite constant temperature, salinity and continued lack of oxygen across the shelf-break. The loss of both total dFe and dFe(II) suggests a conversion of the dFe to particulate form, but studies that have coupled the reduction-oxidation (redox) speciation of both dissolved and particulate phases have not previously been done. Here in this work, we have measured themore » redox speciation and concentrations of both dissolved and particulate forms of Fe in samples collected during the U.S. GEOTRACES Eastern tropical Pacific Zonal Transect (EPZT) cruise in 2013 (GP16). This complete data set allows us to assess possible mechanisms for loss of dFe. We observed an offshore loss of dFe(II) within the oxygen deficient zone (ODZ), where dissolved oxygen is undetectable, accompanied by an increase in total particulate Fe (pFe). Total pFe concentrations were highest in the upper ODZ. X-ray absorption spectroscopy revealed that the pFe maximum was primarily in the Fe(III) form as Fe(III) oxyhydroxides. The remarkable similarity in the distributions of total particulate iron and nitrite suggests a role for nitrite in the oxidation of dFe(II) to pFe(III). Lastly, we present a conceptual model for the rapid redox cycling of Fe that occurs in ODZs, despite the absence of oxygen.« less

Accumulation of Fe oxyhydroxides in the Peruvian oxygen deficient zone implies non-oxygen dependent Fe oxidation

NASA Astrophysics Data System (ADS)

Heller, Maija I.; Lam, Phoebe J.; Moffett, James W.; Till, Claire P.; Lee, Jong-Mi; Toner, Brandy M.; Marcus, Matthew A.

2017-08-01

Oxygen minimum zones (OMZs) have been proposed to be an important source of dissolved iron (Fe) into the interior ocean. However, previous studies in OMZs have shown a sharp decrease in total dissolved Fe (dFe) and/or dissolved Fe(II) (dFe(II)) concentrations at the shelf-break, despite constant temperature, salinity and continued lack of oxygen across the shelf-break. The loss of both total dFe and dFe(II) suggests a conversion of the dFe to particulate form, but studies that have coupled the reduction-oxidation (redox) speciation of both dissolved and particulate phases have not previously been done. Here we have measured the redox speciation and concentrations of both dissolved and particulate forms of Fe in samples collected during the U.S. GEOTRACES Eastern tropical Pacific Zonal Transect (EPZT) cruise in 2013 (GP16). This complete data set allows us to assess possible mechanisms for loss of dFe. We observed an offshore loss of dFe(II) within the oxygen deficient zone (ODZ), where dissolved oxygen is undetectable, accompanied by an increase in total particulate Fe (pFe). Total pFe concentrations were highest in the upper ODZ. X-ray absorption spectroscopy revealed that the pFe maximum was primarily in the Fe(III) form as Fe(III) oxyhydroxides. The remarkable similarity in the distributions of total particulate iron and nitrite suggests a role for nitrite in the oxidation of dFe(II) to pFe(III). We present a conceptual model for the rapid redox cycling of Fe that occurs in ODZs, despite the absence of oxygen.

Kernel-based discriminant feature extraction using a representative dataset

NASA Astrophysics Data System (ADS)

Li, Honglin; Sancho Gomez, Jose-Luis; Ahalt, Stanley C.

2002-07-01

Discriminant Feature Extraction (DFE) is widely recognized as an important pre-processing step in classification applications. Most DFE algorithms are linear and thus can only explore the linear discriminant information among the different classes. Recently, there has been several promising attempts to develop nonlinear DFE algorithms, among which is Kernel-based Feature Extraction (KFE). The efficacy of KFE has been experimentally verified by both synthetic data and real problems. However, KFE has some known limitations. First, KFE does not work well for strongly overlapped data. Second, KFE employs all of the training set samples during the feature extraction phase, which can result in significant computation when applied to very large datasets. Finally, KFE can result in overfitting. In this paper, we propose a substantial improvement to KFE that overcomes the above limitations by using a representative dataset, which consists of critical points that are generated from data-editing techniques and centroid points that are determined by using the Frequency Sensitive Competitive Learning (FSCL) algorithm. Experiments show that this new KFE algorithm performs well on significantly overlapped datasets, and it also reduces computational complexity. Further, by controlling the number of centroids, the overfitting problem can be effectively alleviated.

Organic matter controls of iron incorporation in growing sea ice

NASA Astrophysics Data System (ADS)

Janssens, Julie; Meiners, Klaus M.; Townsend, Ashley T.; Lannuzel, Delphine

2018-03-01

This study presents the first laboratory-controlled sea-ice growth experiment conducted under trace metal clean conditions. The role played by organic matter, in the incorporation of iron (Fe) into sea ice was investigated by means of laboratory ice-growth experiments using a titanium cold-finger apparatus. Experiments were also conducted to understand the role of extracellular polymeric substances (EPS) in the enrichment of ammonium in sea ice. Sea ice was grown from several seawater solutions containing different quantities and qualities of particulate Fe (PFe), dissolved Fe (DFe) and organic matter. Sea ice and seawater were analyzed for particulate organic carbon and nitrogen, macro-nutrients, extracellular EPS, PFe and DFe, and particulate aluminium. The experiments showed that biogenic PFe is preferentially incorporated into sea ice compared to lithogenic PFe. Furthermore, sea ice grown from ultra-violet (UV) and non-UV treated seawaters exhibits contrasting incorporation rates of organic matter and Fe. Whereas the effects of UV-treatments were not always significant, we do find indications that the type or organic matter controls the enrichment of Fe in forming sea ice.. Specifically, we come to the conclusion that the incorporation of DFe is favored by the presence of organic ligands in the source solution.

A tale of two gyres: Contrasting distributions of dissolved cobalt and iron in the Atlantic Ocean during an Atlantic Meridional Transect (AMT-19)

NASA Astrophysics Data System (ADS)

Shelley, Rachel U.; Wyatt, Neil J.; Tarran, Glenn A.; Rees, Andrew P.; Worsfold, Paul J.; Lohan, Maeve C.

2017-11-01

Cobalt (Co) and iron (Fe) are essential for phytoplankton nutrition, and as such constitute a vital link in the marine biological carbon pump. Atmospheric deposition is an important, and in some places the dominant, source of trace elements (TEs) to the global ocean. Dissolved cobalt (dCo) and iron (dFe) were determined along an Atlantic Meridional Transect (AMT-19; Oct/Nov 2009) between 50°N and 40°S in the upper 150 m in order to investigate the behaviour and distribution of these two essential, bioactive TEs. During AMT-19, large differences in the distributions of dCo and dFe were observed. In the North Atlantic gyre provinces, extremely low mixed layer dCo concentrations (23 ± 9 pM) were observed, which contrasts with the relatively high mixed layer dFe concentrations (up to 1.0 nM) coincident with the band of highest atmospheric deposition (∼5-30°N). In the South Atlantic gyre, the opposite trend was observed, with relatively high dCo (55 ± 18 pM) observed throughout the water column, but low dFe concentrations (0.29 ± 0.08 nM). Given that annual dust supply is an order of magnitude greater in the North than the South Atlantic, the dCo distribution was somewhat unexpected. However, the distribution of dCo shows similarities with the distribution of phosphate (PO43-) in the euphotic zone of the Atlantic Ocean, where the North Atlantic gyre is characterised by chronically low PO4, and higher concentrations are observed in the South Atlantic gyre (Mather et al., 2008), suggesting the potential for a similar biological control of dCo distributions. Inverse correlations between dCo and Prochlorococcus abundance in the North Atlantic gyre provinces, combined with extremely low dCo where nitrogen fixation rates were highest (∼20-28°N), suggests the dominance of biological controls on dCo distributions. The contrasting dCo and dFe distributions in the North and South Atlantic gyres provides insights into the differences between the dominant controls on the distribution of these two bioactive trace metals in the central Atlantic Ocean.

Equalizer design techniques for dispersive cables with application to the SPS wideband kicker

NASA Astrophysics Data System (ADS)

Platt, Jason; Hofle, Wolfgang; Pollock, Kristin; Fox, John

2017-10-01

A wide-band vertical instability feedback control system in development at CERN requires 1-1.5 GHz of bandwidth for the entire processing chain, from the beam pickups through the feedback signal digital processing to the back-end power amplifiers and kicker structures. Dispersive effects in cables, amplifiers, pickup and kicker elements can result in distortions in the time domain signal as it proceeds through the processing system, and deviations from linear phase response reduce the allowable bandwidth for the closed-loop feedback system. We have developed an equalizer analog circuit that compensates for these dispersive effects. Here we present a design technique for the construction of an analog equalizer that incorporates the effect of parasitic circuit elements in the equalizer to increase the fidelity of the implemented equalizer. Finally, we show results from the measurement of an assembled backend equalizer that corrects for dispersive elements in the cables over a bandwidth of 10-1000 MHz.

A model of Fe speciation and biogeochemistry at the Tropical Eastern North Atlantic Time-Series Observatory site

NASA Astrophysics Data System (ADS)

Ye, Y.; Völker, C.; Wolf-Gladrow, D. A.

2009-10-01

A one-dimensional model of Fe speciation and biogeochemistry, coupled with the General Ocean Turbulence Model (GOTM) and a NPZD-type ecosystem model, is applied for the Tropical Eastern North Atlantic Time-Series Observatory (TENATSO) site. Among diverse processes affecting Fe speciation, this study is focusing on investigating the role of dust particles in removing dissolved iron (DFe) by a more complex description of particle aggregation and sinking, and explaining the abundance of organic Fe-binding ligands by modelling their origin and fate. The vertical distribution of different particle classes in the model shows high sensitivity to changing aggregation rates. Using the aggregation rates from the sensitivity study in this work, modelled particle fluxes are close to observations, with dust particles dominating near the surface and aggregates deeper in the water column. POC export at 1000 m is a little higher than regional sediment trap measurements, suggesting further improvement of modelling particle aggregation, sinking or remineralisation. Modelled strong ligands have a high abundance near the surface and decline rapidly below the deep chlorophyll maximum, showing qualitative similarity to observations. Without production of strong ligands, phytoplankton concentration falls to 0 within the first 2 years in the model integration, caused by strong Fe-limitation. A nudging of total weak ligands towards a constant value is required for reproducing the observed nutrient-like profiles, assuming a decay time of 7 years for weak ligands. This indicates that weak ligands have a longer decay time and therefore cannot be modelled adequately in a one-dimensional model. The modelled DFe profile is strongly influenced by particle concentration and vertical distribution, because the most important removal of DFe in deeper waters is colloid formation and aggregation. Redissolution of particulate iron is required to reproduce an observed DFe profile at TENATSO site. Assuming colloidal iron is mainly composed of inorganic colloids, the modelled colloidal to soluble iron ratio is lower that observations, indicating the importance of organic colloids.

Factors Influencing the Diversity of Iron Uptake Systems in Aquatic Microorganisms

PubMed Central

Desai, Dhwani K.; Desai, Falguni D.; LaRoche, Julie

2012-01-01

Iron (Fe) is an essential micronutrient for many processes in all living cells. Dissolved Fe (dFe) concentrations in the ocean are of the order of a few nM, and Fe is often a factor limiting primary production. Bioavailability of Fe in aquatic environments is believed to be primarily controlled through chelation by Fe-binding ligands. Marine microbes have evolved different mechanisms to cope with the scarcity of bioavailable dFe. Gradients in dFe concentrations and diversity of the Fe-ligand pool from coastal to open ocean waters have presumably imposed selection pressures that should be reflected in the genomes of microbial communities inhabiting the pelagic realm. We applied a hidden Markov model (HMM)-based search for proteins related to cellular iron metabolism, and in particular those involved in Fe uptake mechanisms in 164 microbial genomes belonging to diverse taxa and occupying different aquatic niches. A multivariate statistical approach demonstrated that in phototrophic organisms, there is a clear influence of the ecological niche on the diversity of Fe uptake systems. Extending the analyses to the metagenome database from the Global Ocean Sampling expedition, we demonstrated that the Fe uptake and homeostasis mechanisms differed significantly across marine niches defined by temperatures and dFe concentrations, and that this difference was linked to the distribution of microbial taxa in these niches. Using the dN/dS ratios (which signify the rate of non-synonymous mutations) of the nucleotide sequences, we identified that genes encoding for TonB, Ferritin, Ferric reductase, IdiA, ZupT, and Fe2+ transport proteins FeoA and FeoB were evolving at a faster rate (positive selection pressure) while genes encoding ferrisiderophore, heme and Vitamin B12 uptake systems, siderophore biosynthesis, and IsiA and IsiB were under purifying selection pressure (evolving slowly). PMID:23087680

Cost effectiveness of a telephone intervention to promote dilated fundus examination in adults with diabetes mellitus

PubMed Central

Schechter, Clyde B; Basch, Charles E; Caban, Arlene; Walker, Elizabeth A

2008-01-01

In a clinical trial, we have previously shown that a telephone intervention can significantly increase participation in dilated fundus examination (DFE) screening among low-income adults with diabetes. Here the costs and cost-effectiveness ratio of this intervention are calculated. Intervention effectiveness was estimated as the difference in DFE utilization between the telephone intervention and print groups from the clinical trial multiplied by the size of the telephone intervention group. A micro-costing approach was used. Personnel time was aggregated from logs kept during the clinical trial of the intervention. Wage rates were taken from a commercial compensation database. Telephone charges were estimated based on prevailing fees. The cost-effectiveness ratio was calculated as the ratio of total costs of the intervention to the number of DFEs gained by the intervention. A sensitivity analysis estimated the cost-effectiveness of a more limited telephone intervention. A probabilistic sensitivity analysis using bootstrap samples from the clinical trial results quantified the uncertainties in resource utilization and intervention effectiveness. Net intervention costs were US$18,676.06, with an associated gain of 43.7 DFEs and 16.4 new diagnoses of diabetic retinopathy. The cost-effectiveness ratio is US$427.37 per DFE gained. A restricted intervention limiting the number of calls to 5, as opposed to 7, would achieve the same results, but would cost approximately 17% less. In the probabilistic sensitivity analysis, the 5th and 95th percentiles of the cost-effectiveness ratio were US$304.05 and US$692.52 per DFE gained, respectively. Our telephone intervention is more expensive than simple mail or telephone reminders used in other settings to promote preventive care; it is, however, also considerably more effective, and is effective in a low-income minority population at greater risk for diabetes complications. The costs are dominated by labor costs, and may be substantially defrayed, without loss of effectiveness, by restricting the number of telephone calls to 5 per patient. PMID:19668428

Providing Students with Formative Audio Feedback

ERIC Educational Resources Information Center

Brearley, Francis Q.; Cullen, W. Rod

2012-01-01

The provision of timely and constructive feedback is increasingly challenging for busy academics. Ensuring effective student engagement with feedback is equally difficult. Increasingly, studies have explored provision of audio recorded feedback to enhance effectiveness and engagement with feedback. Few, if any, of these focus on purely formative…

Effects of installation of F101 DFE exhaust nozzles on the afterbody-nozzle characteristics of the F-14 airplane

NASA Technical Reports Server (NTRS)

Reubush, D. E.; Carlson, J. R.

1982-01-01

A wind-tunnel investigation was conducted to determine the effects of F101 DFE (derivative fighter engine) nozzle axial positioning on the afterbody-nozzle longitudinal aerodynamic characteristics of the F-14 airplane. The model was tested in the Langley 16-Foot Transonic Tunnel at Mach numbers from 0.7 to 1.25 and angles of attack from about -2 to 6 degrees. Compressed air was used to simulate nozzle exhaust flow at jet total-pressure ratios from 1 (jet off) to about 8. The results of the investigation show that for subsonic Mach numbers the intermediate cruise nozzle position of the three positions tested resulted in the lowest drag.

Combined magnetic vector-scalar potential finite element computation of 3D magnetic field and performance of modified Lundell alternators in Space Station applications. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Wang, Ren H.

1991-01-01

A method of combined use of magnetic vector potential (MVP) based finite element (FE) formulations and magnetic scalar potential (MSP) based FE formulations for computation of three-dimensional (3D) magnetostatic fields is developed. This combined MVP-MSP 3D-FE method leads to considerable reduction by nearly a factor of 3 in the number of unknowns in comparison to the number of unknowns which must be computed in global MVP based FE solutions. This method allows one to incorporate portions of iron cores sandwiched in between coils (conductors) in current-carrying regions. Thus, it greatly simplifies the geometries of current carrying regions (in comparison with the exclusive MSP based methods) in electric machinery applications. A unique feature of this approach is that the global MSP solution is single valued in nature, that is, no branch cut is needed. This is again a superiority over the exclusive MSP based methods. A Newton-Raphson procedure with a concept of an adaptive relaxation factor was developed and successfully used in solving the 3D-FE problem with magnetic material anisotropy and nonlinearity. Accordingly, this combined MVP-MSP 3D-FE method is most suited for solution of large scale global type magnetic field computations in rotating electric machinery with very complex magnetic circuit geometries, as well as nonlinear and anisotropic material properties.

Automotive Refinishing Industry: Isocyanates Profile

EPA Pesticide Factsheets

The isocyanates profile document is part of the DfE Auto Refinishing Shop Project and is intended to provide information on refinishing, control technologies, and regulatory status regarding isocyanate compounds

Redox speciation of dissolved iron in the northeastern atlantic ocean.

NASA Astrophysics Data System (ADS)

Ussher, S. J.; Achterberg, E. P.; Worsfold, P. J.

2003-04-01

Dissolved iron (<0.2 micron) and iron(II) (<0.2 micron) distributions were determined during the Iron from Below and Iron from Above research cruises in the North Eastern Atlantic Ocean. The cruises were part of the EU Ironages project. Iron(II) was measured on-board ship using an iron(II) specific, automated flow injection analyser with luminol chemiluminescence detection [1]. Total dissolved iron (DFe) was determined in a land-based laboratory, using the same FI technique but with prior reduction of iron(III) to iron(II) [2]. The limits of detection for the methods were 5 -15 pM and 35 pM respectively, the analysis time was 8 - 10 minutes per sample (minimum of 3 replicates). The Iron from Below expedition took place over the European Continental Shelf, 200 km South West of Brittany (France) in March 2002. A transect between 47.61°N, 4.24°W and 46.00°N, 8.01°W was completed. Over the transect, the depth increased from 100 m to 5000 m. Iron(II) concentrations ranged between 10 and 100 pM and DFe between 0.2 and 1 nM, with the higher concentrations (Fe(II) ca. > 50 pM and DFe ca. > 0.8 nM) generally found in the shallow shelf waters. These observations imply that benthic inputs and sediment resuspension may form important inputs of dissolved iron and iron(II) in the shelf waters. Iron speciation measurements were also made for underway surface and shallow cast samples during the Iron from Above cruise October 2002. Fe(II) and DFe concentrations were typically 5 to 50 pM and 0.2 to 0.6 nM, respectively. Sampling was carried out within a grid in the Canary Basin around 5 degrees W of the Canary Islands, an area assumed to be strongly influenced by the Saharan dust plume. Observed Fe(II) concentrations are compared and ratioed to the DFe concentrations, and indicate that iron(II) forms an important fraction (between 5 and 15%) of the total dissolved iron concentration in the study areas. Data plots for surface samples are presented with the corresponding physical oceanographic and solar irradiance data. The concentrations of Fe(II) observed during our studies exceed the values predicted from thermodynamic equilibrium modelling. This indicates that there is a steady supply of Fe(II) (possibly from photoreduction and/or biological origins) and/or Fe(II) is prevented from oxidation through stabilisation mechanisms (possibly by organic ligands). [1] A. R. Bowie, E. P. Achterberg, P. N. Sedwick, S. Ussher, P. J. Worsfold, Environ. Sci. Technol., 36, (2002) 4600. [2] A. R. Bowie, E. P. Achterberg, R. F. C. Mantoura, P. J. Worsfold, Anal. Chim. Acta, 377, (1998) 113.

a Study of Vibrational Mode Coupling in 2-FLUOROETHANOL and 1,2-DIFLUOROETHANE Using High-Resolution Infrared Spectroscopy.

NASA Astrophysics Data System (ADS)

Mork, Steven Wayne

High resolution infrared spectroscopy was used to examine intramolecular vibrational interactions in 2 -fluoroethanol (2FE) and 1,2-difluoroethane (DFE). A high resolution infrared spectrophotometer capable of better than 10 MHz spectral resolution was designed and constructed. The excitation source consists of three lasers: an argon-ion pumped dye laser which pumps a color -center laser. The infrared beam from the color-center laser is used to excite sample molecules which are rotationally and vibrationally cooled in a supersonic molecular beam. Rovibrational excitation of the sample molecules is detected by monitoring the kinetic energy of the molecular beam with a bolometer. The high resolution infrared spectrum of 2FE was collected and analyzed over the 2977-2990 cm^ {-1}^ectral region. This region contains the asymmetric CH stretch on the fluorinated carbon. The spectrum revealed extensive perturbations in the rotational fine structure. Analysis of these perturbations has provided a quantitative measure of selective vibrational mode coupling between the C-H stretch and its many neighboring dark vibrational modes. Interestingly, excitation of the C-H stretch is known to induce a photoisomerization reaction between 2FE's Gg^' and Tt conformers. Implications of the role of mode coupling in the reaction mechanism are also addressed. Similarly, the high resolution infrared spectrum of DFE was collected and analyzed over the 2978-2996 cm ^{-1}^ectral region. This region contains the symmetric combination of asymmetric C-H stretches in DFE. Perturbations in the rotational fine structure indicate vibrational mode coupling to a single dark vibrational state. The dark state is split by approximately 19 cm^{-1} due to tunneling between two identical gauche conformers. The coupling mechanism is largely anharmonic with a minor component of B/C-plane Coriolis coupling. Effects of centrifugal distortion along the molecular A-axis are also observed. The coupled vibrational mode has been identified as containing C-C torsion, CCF bend and CH_2 rock. As in 2FE, DFE undergoes an isomerization reaction upon excitation of the C-H stretch. Coupling between the C-H stretch and C-C torsion is addressed with respect to the reaction mechanism.

Implementing Cleaner Printed Wiring Board Technologies: Surface Finishes

EPA Pesticide Factsheets

This document describes the problems, solutions, and time and effort involved in implementing alternative surface finish technologies, and this guide is produced as part of the DfE Printed Wiring Board Project

Feedback Valence Affects Auditory Perceptual Learning Independently of Feedback Probability

PubMed Central

Amitay, Sygal; Moore, David R.; Molloy, Katharine; Halliday, Lorna F.

2015-01-01

Previous studies have suggested that negative feedback is more effective in driving learning than positive feedback. We investigated the effect on learning of providing varying amounts of negative and positive feedback while listeners attempted to discriminate between three identical tones; an impossible task that nevertheless produces robust learning. Four feedback conditions were compared during training: 90% positive feedback or 10% negative feedback informed the participants that they were doing equally well, while 10% positive or 90% negative feedback informed them they were doing equally badly. In all conditions the feedback was random in relation to the listeners’ responses (because the task was to discriminate three identical tones), yet both the valence (negative vs. positive) and the probability of feedback (10% vs. 90%) affected learning. Feedback that informed listeners they were doing badly resulted in better post-training performance than feedback that informed them they were doing well, independent of valence. In addition, positive feedback during training resulted in better post-training performance than negative feedback, but only positive feedback indicating listeners were doing badly on the task resulted in learning. As we have previously speculated, feedback that better reflected the difficulty of the task was more effective in driving learning than feedback that suggested performance was better than it should have been given perceived task difficulty. But contrary to expectations, positive feedback was more effective than negative feedback in driving learning. Feedback thus had two separable effects on learning: feedback valence affected motivation on a subjectively difficult task, and learning occurred only when feedback probability reflected the subjective difficulty. To optimize learning, training programs need to take into consideration both feedback valence and probability. PMID:25946173

Safer Choice Partner of the Year Awards Application Form

EPA Pesticide Factsheets

EPA's Design for the Environment program developed the Safer Product Labeling Program Partner of the Year Award program to recognize DfE stakeholders that have furthered the safer chemistry goals of the program

Note: a novel vacuum ultraviolet light source assembly with aluminum-coated electrodes for enhancing the ionization efficiency of photoionization mass spectrometry.

PubMed

Zhu, Zhixiang; Wang, Jian; Qiu, Keqing; Liu, Chengyuan; Qi, Fei; Pan, Yang

2014-04-01

A novel vacuum ultraviolet (VUV) light source assembly (VUVLSA) for enhancing the ionization efficiency of photoionization mass spectrometer has been described. The VUVLSA composes of a Krypton lamp and a pair of disk electrodes with circular center cavities. The two interior surfaces that face the photoionization region were aluminum-coated. VUV light can be reflected back and forth in the photoionization region between the electrodes, thus the photoionization efficiency can be greatly enhanced. The performances of two different shaped electrodes, the coated double flat electrodes (DFE), and double conical electrodes, were studied. We showed that the signal amplification of coated DFE is around 4 times higher than that of uncoated electrodes without VUV light reflection. The relationship between the pressure of ionization chamber and mass signal enhancement has also been studied.

Afterslip, tremor, and the Denali fault earthquake

USGS Publications Warehouse

Gomberg, Joan; Prejean, Stephanie; Ruppert, Natalia

2012-01-01

We tested the hypothesis that afterslip should be accompanied by tremor using observations of seismic and aseismic deformation surrounding the 2002 M 7.9 Denali fault, Alaska, earthquake (DFE). Afterslip happens more frequently than spontaneous slow slip and has been observed in a wider range of tectonic environments, and thus the existence or absence of tremor accompanying afterslip may provide new clues about tremor generation. We also searched for precursory tremor, as a proxy for posited accelerating slip leading to rupture. Our search yielded no tremor during the five days prior to the DFE or in several intervals in the three months after. This negative result and an array of other observations all may be explained by rupture penetrating below the presumed locked zone into the frictional transition zone. While not unique, such an explanation corroborates previous models of megathrust and transform earthquake ruptures that extend well into the transition zone.

FN-DFE: Fuzzy-Neural Data Fusion Engine for Enhanced State-Awareness of Resilient Hybrid Energy System

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

Ondrej Linda; Dumidu Wijayasekara; Milos Manic

Resiliency and improved state-awareness of modern critical infrastructures, such as energy production and industrial systems, is becoming increasingly important. As control systems become increasingly complex, the number of inputs and outputs increase. Therefore, in order to maintain sufficient levels of state-awareness, a robust system state monitoring must be implemented that correctly identifies system behavior even when one or more sensors are faulty. Furthermore, as intelligent cyber adversaries become more capable, incorrect values may be fed to the operators. To address these needs, this paper proposes a Fuzzy-Neural Data Fusion Engine (FN-DFE) for resilient state-awareness of control systems. The designed FN-DFEmore » is composed of a three-layered system consisting of: 1) traditional threshold based alarms, 2) anomalous behavior detector using self-organizing fuzzy logic system, and 3) artificial neural network based system modeling and prediction. The improved control system state-awareness is achieved via fusing input data from multiple sources and combining them into robust anomaly indicators. In addition, the neural network based signal predictions are used to augment the resiliency of the system and provide coherent state-awareness despite temporary unavailability of sensory data. The proposed system was integrated and tested with a model of the Idaho National Laboratory’s (INL) hybrid energy system facility know as HYTEST. Experimental results demonstrate that the proposed FN-DFE provides timely plant performance monitoring and anomaly detection capabilities. It was shown that the system is capable of identifying intrusive behavior significantly earlier than conventional threshold based alarm systems.« less

Improved analysis tool for concrete pavement : [project summary].

DOT National Transportation Integrated Search

2017-10-01

University of Florida researchers developed 3D-FE models to more accurately predict the behavior of concrete slabs. They also followed up on a project to characterize strain gauge performance for a Florida Department of Transportation (FDOT) concrete...

Effect of Behavioral Intervention on Dilated Fundus Examination Rates in Older African American Individuals With Diabetes Mellitus: A Randomized Clinical Trial.

PubMed

Weiss, David M; Casten, Robin J; Leiby, Benjamin E; Hark, Lisa A; Murchison, Ann P; Johnson, Deiana; Stratford, Shayla; Henderer, Jeffrey; Rovner, Barry W; Haller, Julia A

2015-09-01

African American individuals are at high risk of diabetes mellitus and diabetic retinopathy but have suboptimal rates of dilated fundus examinations (DFEs). Early intervention is crucial for the prevention of diabetic retinopathy in this high-risk population. To test the efficacy of behavioral activation for diabetic retinopathy prevention on rates of DFEs in older African American individuals with diabetes mellitus. Masked randomized clinical trial at 2 urban medical centers from October 1, 2010, to May 31, 2014. Participants included 206 African American individuals 65 years and older with diabetes mellitus who had not obtained a DFE in the preceding 12 months. Participants were randomized to either behavioral activation for diabetic retinopathy prevention, a behavioral intervention designed to provide education, facilitate identifying and addressing health care barriers, and promote goal setting to improve rates of DFEs, or supportive therapy, a control condition. The primary outcome was medical documentation of a DFE at 6 months' follow-up. Secondary outcomes included the Risk Perceptions and Risk Knowledge Survey of Diabetes Mellitus, Diabetes Self-Care Inventory, Patient Health Questionnaire 9, and National Eye Institute Vision Function Questionnaire 25 scores and hemoglobin A1c levels. More participants in the behavioral activation for diabetic retinopathy prevention group (87.9%) obtained a DFE compared with those in the supportive therapy group (34.1%) by the 6-month follow-up assessment (P < .001). Overall, participants in the behavioral activation for diabetic retinopathy prevention group were 2.5 times more likely to obtain a DFE compared with those in the supportive therapy group (risk ratio = 2.58; 95% CI, 1.91-3.48; P < .001). The intervention had no short-term effect on secondary outcomes of hemoglobin A1c levels, depression, or the Risk Perceptions and Risk Knowledge Survey of Diabetes Mellitus or National Eye Institute Vision Function Questionnaire 25 composite scores; however, both groups had improved adherence to diabetes mellitus self-care behaviors from baseline to 6-month follow-up. Behavioral activation for diabetic retinopathy prevention significantly increased rates of DFEs in older African American individuals with diabetes mellitus. Behavioral interventions may have the potential to positively affect screening for diabetic retinopathy in at-risk populations. clinicaltrials.gov Identifier: NCT01179555.

The Use of Objective Structured Self-Assessment and Peer-Feedback (OSSP) for Learning Communication Skills: Evaluation Using a Controlled Trial

ERIC Educational Resources Information Center

Perera, Jennifer; Mohamadou, Galy; Kaur, Satpal

2010-01-01

Feedback is essential to guide students towards expected performance goals. The usefulness of teacher feedback on improving communication skills (CS) has been well documented. It has been proposed that self-assessment and peer-feedback has an equally important role to play in enhancing learning. This is the focus of this study. Objectively…

Locus of Control and Effects of Failure on Performance and Perceived Competence

ERIC Educational Resources Information Center

Shavit, Hana; Rabinowitz, Aaron

1978-01-01

Reactions to ego related performance feedback of 117 internal and external locus of control eighth-grade children were investigated. Both internals and externals were equally pleased by success feedback and displeased by failure, and their competence judgment was influenced by the feedback received. However, internals exhibited more effective…

Performance analysis of passive time reversal communication technique for multipath interference in shallow sea acoustic channel

NASA Astrophysics Data System (ADS)

Kida, Yukihiro; Shimura, Takuya; Deguchi, Mitsuyasu; Watanabe, Yoshitaka; Ochi, Hiroshi; Meguro, Koji

2017-07-01

In this study, the performance of passive time reversal (PTR) communication techniques in multipath rich underwater acoustic environments is investigated. It is recognized empirically and qualitatively that a large number of multipath arrivals could generally raise the demodulation result of PTR. However, the relationship between multipath and the demodulation result is hardly evaluated quantitatively. In this study, the efficiency of the PTR acoustic communication techniques for multipath interference cancelation was investigated quantitatively by applying a PTR-DFE (decision feed-back filter) scheme to a synthetic dataset of a horizontal underwater acoustic channel. Mainly, in this study, we focused on the relationship between the signal-to-interference ratio (SIR) of datasets and the output signal-to-noise ratio (OSNR) of demodulation results by a parametric study approach. As a result, a proportional relation between SIR and OSNR is confirmed in low-SNR datasets. It was also found that PTR has a performance limitation, that is OSNR converges to a typical value depending on the number of receivers. In conclusion, results indicate that PTR could utilize the multipath efficiently and also withstand the negative effects of multipath interference at a given limitation.

Notification: Preliminary Research on EPA's Design for the Environment Product Labeling Program OIG

EPA Pesticide Factsheets

Project #OPE-FY14-4012, November 06, 2013. The Office of Inspector General (OIG) is starting preliminary research on the U.S. Environmental Protection Agency’s (EPA’s) Design for the Environment (DfE) Product Labeling Program.

Flemish Primary Teachers' Use of School Performance Feedback and the Relationship with School Characteristics

ERIC Educational Resources Information Center

Vanhoof, Jan; Verhaeghe, Goedele; Van Petegem, Peter; Valcke, Martin

2012-01-01

Background: Schools are increasingly confronted with the challenges that information about school performance brings with it. It is common for schools' use of performance feedback to be limited. Equally, however, there are documented cases in which school performance feedback is meaningfully used. Purpose: This study looks at how Flemish primary…

Folate intake and the MTHFR C677T genotype influence choline status in young Mexican American women☆

PubMed Central

Abratte, Christian M.; Wang, Wei; Li, Rui; Moriarty, David J.; Caudill, Marie A.

2009-01-01

Numerous studies have reported a relationship between folate status, the methylenetetrahydrofolate reductase (MTHFR) 677C→T variant and disease risk. Although folate and choline metabolism are inter-related, only limited data are available on the relationship between choline and folate status in humans. This study sought to examine the influences of folate intake and the MTHFR 677C→T variant on choline status. Mexican-American women (n =43; 14 CC, 12 CT and 17 TT) consumed 135 μg/day as dietary folate equivalents (DFE) for 7 weeks followed by randomization to 400 or 800 μg DFE/day for 7 weeks. Throughout the study, total choline intake remained unchanged at ∼350 mg/day. Plasma concentrations of betaine, choline, glycerophosphocholine, phosphatidylcholine and sphingomyelin were measured via LC-MS/MS for Weeks 0, 7 and 14. Phosphatidylcholine and sphingomyelin declined ( P=.001, P=.009, respectively) in response to folate restriction and increased ( P=.08, P=.029, respectively) in response to folate treatment. The increase in phosphatidylcholine occurred in response to 800 ( P=.03) not 400 ( P=.85) μg DFE/day (week×folate interaction, P=.017). The response of phosphatidylcholine to folate intake appeared to be influenced by MTHFR C677T genotype. The decline in phosphatidylcholine during folate restriction occurred primarily in women with the CC or CT genotype and not in the TT genotype (week×genotype interaction, P=.089). Moreover, when examined independent of folate status, phosphatidylcholine was higher ( P <.05) in the TT genotype relative to the CT genotype. These data suggest that folate intake and the MTHFR C677T genotype influence choline status in humans. PMID:17588738

Meltwater Pathways and Iron Delivery to the Antarctic Coastal Ocean

NASA Astrophysics Data System (ADS)

Null, K. A.; Corbett, D. R.; Crenshaw, J.; Peterson, R. N.; Peterson, L.; Buck, C. S.; Lyons, W. B.

2016-02-01

Freshwater inputs to the Antarctic coastal ocean can occur through multiple pathways including calving, streams, and groundwater discharge. The impacts of submarine groundwater discharge on polar ecosystems are generally poorly understood and, until recently, had not been considered as an important physical process along the coast of the Antarctic continent. Here, we present a study utilizing multiple tracers (radium, radon, and stable water isotopes) to quantify freshwater inputs and chemical constituent fluxes associated with multiple discharge pathways, including submarine groundwater discharge, along the Western Antarctic Peninsula. Previous research has shown that primary production in iron-limited waters offshore of the Antarctic Peninsula is fueled in part by continentally-derived sediments, and our work demonstrates that subglacial/submarine groundwater discharge (SSGD) to continental shelf waters in the region is also an important source of dissolved iron (6.4 Gg yr-1; dFe). For reference, this flux equates to approximately 25 times the iron flux from calving in the study area. SSGD also contributed a significantly higher macronutrient flux than calving, although calving contributed more than twice as much freshwater. Thus, SSGD is likely a much more important source of macronutrients and dFe to the nearshore coastal ocean along the Western Antarctic Peninsula, and potentially to the continental shelf and offshore waters of the entire continent than previously recognized. If we assume similar discharge rates along the entire Antarctic coastline ( 45,000 km), the delivery of dFe via SSGD ( 216 Gg yr-1) is comparable to the other fluxes of Fe to the Southern Ocean via dust, icebergs, and glacial runoff from the Antarctic Ice Sheet, and should be considered in future geochemical budgets.

40 CFR 80.1611 - Standards and requirements for certified ethanol denaturant.

Code of Federal Regulations, 2014 CFR

2014-07-01

... certified ethanol denaturant. 80.1611 Section 80.1611 Protection of Environment ENVIRONMENTAL PROTECTION....1611 Standards and requirements for certified ethanol denaturant. Producers and importers of ethanol denaturant that is suitable for the manufacture of denatured fuel ethanol (DFE) meeting federal quality...

Replacement of sugars to hydrogen production by Rhodobacter capsulatus using dark fermentation effluent as substrate.

PubMed

Silva, Felipe Thales Moreira; Moreira, Luiza Rojas; de Souza Ferreira, Juliana; Batista, Fabiana Regina Xavier; Cardoso, Vicelma Luiz

2016-01-01

Hydrogen is a promising alternative for the increased global energy demand since it has high energy density and is a clean fuel. The aim of this work was to evaluate the photo-fermentation by Rhodobacter capsulatus, using the dark fermentation effluent as substrate. Different systems were tested by changing the type of sugar in the dark fermentation, investigating the influence of supplementing DFE with sugar and adding alternate and periodically lactose and glucose throughout the process. The supplementation of the DFE with sugar resulted in higher H2 productivity and the replacement of the sugars repeatedly during the photo-fermentation process was important to maintain the cell culture active. By controlling the residual amount of sugar, bacteria inhibition was avoided; lactic acid, that was toxic to the biomass, was consumed and the metabolic route of butyric acid production was predominant. Under optimum conditions, the H2 productivity reached 208.40mmolH2/Ld in 52h. Copyright © 2015 Elsevier Ltd. All rights reserved.

Supporting Learners' Agentic Engagement with Feedback: A Systematic Review and a Taxonomy of Recipience Processes

ERIC Educational Resources Information Center

Winstone, Naomi E.; Nash, Robert A.; Parker, Michael; Rowntree, James

2017-01-01

Much has been written in the educational psychology literature about effective feedback and how to deliver it. However, it is equally important to understand how learners actively receive, engage with, and implement feedback. This article reports a systematic review of the research evidence pertaining to this issue. Through an analysis of 195…

The Timing of Feedback on Mathematics Problem Solving in a Classroom Setting

ERIC Educational Resources Information Center

Fyfe, Emily R.; Rittle-Johnson, Bethany

2015-01-01

Feedback is a ubiquitous learning tool that is theorized to help learners detect and correct their errors. The goal of this study was to examine the effects of feedback in a classroom context for children solving math equivalence problems (problems with operations on both sides of the equal sign). The authors worked with children in 7 second-grade…

Generation of GHS Scores from TEST and online sources

EPA Science Inventory

Alternatives assessment frameworks such as DfE (Design for the Environment) evaluate chemical alternatives in terms of human health effects, ecotoxicity, and fate. T.E.S.T. (Toxicity Estimation Software Tool) can be utilized to evaluate human health in terms of acute oral rat tox...

40 CFR 80.1600 - Additional definitions for subpart O.

Code of Federal Regulations, 2014 CFR

2014-07-01

... California. Certified ethanol denaturant means ethanol denaturant that meets the requirements of § 80.1611. Certified Sulfur-FRGAS has the meaning given in § 80.1666(a)(5). Denatured fuel ethanol (DFE) means an.... Ethanol denaturant means previously certified gasoline (including previously certified blendstocks for...

Fe3+ partitioning during basalt differentiation on Mars: insights into the oxygen fugacity of the shergottite mantle source(s).

NASA Astrophysics Data System (ADS)

Medard, E.; Martin, A. M.; Collinet, M.; Righter, K.; Grove, T. L.; Newville, M.; Lanzirotti, A.

2014-12-01

The partitioning of Fe3+ between silicate melts and minerals is a key parameter to understand magmatic processes, as it is directly linked to oxygen fugacity (fO2). fO2 is, a priori, not a constant during magmatic processes, and its evolution depends on the compatibility of Fe3+. We have experimentally determined the partition coefficients of Fe3+ between augite, pigeonite, and silicate melt, and use them to constrain the fO2of the martian mantle and of differentiated martian basalts. A series of experiments on various martian basaltic compositions were performed under controlled fO2 in one-atmosphere gas-mixing furnaces. Fe3+/Fetotal ratios in silicate melts and pyroxenes were determined using synchrotron Fe K-edge XANES on the 13 IDE beamline at APS (Argonne). Fe3+ mineral/melt partition coefficients (DFe3+) for augite and pigeonite were obtained with a relative uncertainty of 10-15 %. Both are constant over a wide range of oxygen fugacity (FMQ-2.5 to FMQ+2.0). DFe3+ for augite and pigeonite are broadly consistent with previous data by [1], but DFe3+ for augite is significantly higher (by a factor of 2) than the indirect determinations of [2]. Since augites in [2] are extremely poor in iron compared to ours (0.18 wt% vs 13 wt% FeO), this strongly suggests that DFe3+ varies with Mg#, indicating that Fe3+is more compatible than previously thought in terrestrial mantle pyroxenes (3 wt% FeO) as well. Crystallization paths for shergottite parental melts have been calculated using the MELTS software, combined with our partition coefficients. fO2 in the residual melts is calculated from the models of [3] and [4]. It stays relatively constant at high temperatures, but increases very strongly during the latest stages of crystallization. These results explain the large range of fO2 determined in enriched shergottites. In order to estimate the fO2 of the martian mantle, only the highest temperature phases in the most primitive martian samples should be used. The most primitive shergottites record a mantle fO2 around FMQ-2.5, consistent with the lowest fO2estimated for surface basalts [5]. [1] McCanta et al. (2004) Am Min 89:1685-1693; [2] Mallmann and O'Neill (2009) J Petrol 50:1765-1794; [3] Righter et al. (2013) Am Min 98:616-628; [4] Kress and Carmichael (1991) CMP 108:82-92; [5] Schmidt ME et al. (2014) EPSL 384:198-208.

Lp-stability (1 less than or equal to p less than or equal to infinity) of multivariable nonlinear time-varying feedback systems that are open-loop unstable. [noting unstable convolution subsystem forward control and time varying nonlinear feedback

NASA Technical Reports Server (NTRS)

Callier, F. M.; Desoer, C. A.

1973-01-01

A class of multivariable, nonlinear time-varying feedback systems with an unstable convolution subsystem as feedforward and a time-varying nonlinear gain as feedback was considered. The impulse response of the convolution subsystem is the sum of a finite number of increasing exponentials multiplied by nonnegative powers of the time t, a term that is absolutely integrable and an infinite series of delayed impulses. The main result is a theorem. It essentially states that if the unstable convolution subsystem can be stabilized by a constant feedback gain F and if incremental gain of the difference between the nonlinear gain function and F is sufficiently small, then the nonlinear system is L(p)-stable for any p between one and infinity. Furthermore, the solutions of the nonlinear system depend continuously on the inputs in any L(p)-norm. The fixed point theorem is crucial in deriving the above theorem.

Space-time adaptive decision feedback neural receivers with data selection for high-data-rate users in DS-CDMA systems.

PubMed

de Lamare, Rodrigo C; Sampaio-Neto, Raimundo

2008-11-01

A space-time adaptive decision feedback (DF) receiver using recurrent neural networks (RNNs) is proposed for joint equalization and interference suppression in direct-sequence code-division multiple-access (DS-CDMA) systems equipped with antenna arrays. The proposed receiver structure employs dynamically driven RNNs in the feedforward section for equalization and multiaccess interference (MAI) suppression and a finite impulse response (FIR) linear filter in the feedback section for performing interference cancellation. A data selective gradient algorithm, based upon the set-membership (SM) design framework, is proposed for the estimation of the coefficients of RNN structures and is applied to the estimation of the parameters of the proposed neural receiver structure. Simulation results show that the proposed techniques achieve significant performance gains over existing schemes.

Generation of Alternative Assessment Scores using TEST and online data sources

EPA Science Inventory

Alternatives assessment frameworks such as DfE (Design for the Environment) evaluate chemical alternatives in terms of human health effects, ecotoxicity, and fate. T.E.S.T. (Toxicity Estimation Software Tool) can be utilized to evaluate human health in terms of acute oral rat tox...

Chemistry within Molecular Clusters

DTIC Science & Technology

1992-05-29

within van der Waals clusters. 23 They include the generation of (C2H4F 2),,>4H+ ions from 1,1- difluoroethane clusters, 24 the generation of (CH 3...fragment ions, and identification of the molecule must be made by the characteristic fragmentation pattern. The mass spectrum of 1,1- difluoroethane (DFE

The Impact of "Achievement for All" on School Leadership

ERIC Educational Resources Information Center

Blandford, Sonia

2013-01-01

The "Achievement for All" (AfA) pilot initiative, delivered in partnership by the Department for Education (DfE), (formerly the Department for Children, Schools and Families [DCSF]), National Strategies and the National College (NCSL), aims to increase the attainment and progress of children in schools with special educational needs and…

77 FR 10573 - Meeting of the Department of Justice's (DOJ's) National Motor Vehicle Title Information System...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-22

... Department of Justice's (DOJ's) National Motor Vehicle Title Information System (NMVTIS) Federal Advisory... announcement of a meeting of DOJ's National Motor Vehicle Title Information System (NMVTIS) Federal Advisory.... FOR FURTHER INFORMATION CONTACT: Todd Brighton, Designated Federal Employee (DFE), Bureau of Justice...

78 FR 51747 - Meeting of the Department of Justice's (DOJ's) National Motor Vehicle Title Information System...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-21

... Department of Justice's (DOJ's) National Motor Vehicle Title Information System (NMVTIS) Federal Advisory... announcement of a meeting of DOJ's National Motor Vehicle Title Information System (NMVTIS) Federal Advisory.... FOR FURTHER INFORMATION CONTACT: Todd Brighton, Designated Federal Employee (DFE), Bureau of Justice...

76 FR 38209 - Meeting of the Department of Justice's (DOJ's) National Motor Vehicle Title Information System...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-29

... Department of Justice's (DOJ's) National Motor Vehicle Title Information System (NMVTIS) Federal Advisory... announcement of a meeting of DOJ's National Motor Vehicle Title Information System (NMVTIS) Federal Advisory... FURTHER INFORMATION CONTACT: Alissa Huntoon, Designated Federal Employee (DFE), Bureau of Justice...

Learner-Valued Interactions: Research into Practice

ERIC Educational Resources Information Center

Ley, Kathryn; Gannon-Cook, Ruth

2014-01-01

Online learners provide feedback that does not always match with the expectations of what university administration would expect from their feedback. Learners do not value all instructional features and conditions equally, nor do they view many of the instructional and technology features as being necessarily helpful. This paper presents research…

Identification of pilot-vehicle dynamics from simulation and flight test

NASA Technical Reports Server (NTRS)

Hess, Ronald A.

1990-01-01

The paper discusses an identification problem in which a basic feedback control structure, or pilot control strategy, is hypothesized. Identification algorithms are employed to determine the particular form of pilot equalization in each feedback loop. It was found that both frequency- and time-domain identification techniques provide useful information.

Language Trends 2010 Secondary (CILT, ALL, ISMLA) Data Report

ERIC Educational Resources Information Center

CILT, the National Centre for Languages, 2011

2011-01-01

This survey has been carried out annually since 2002 to track developments in language provision and take up in secondary schools. The following sections are included in this analysis of key results from the Secondary Language Trends survey: (1) Survey background, methodology and sample design; (2) DfE (Department for Education) data trends of…

Reframing the English Grammar Schools Debate

ERIC Educational Resources Information Center

Morris, Rebecca; Perry, Thomas

2017-01-01

In October 2015 the Department for Education (DfE) permitted a grammar school in Tonbridge, Kent, to open up an annexe in Sevenoaks, 10 miles away. Amidst claims that the annexe was essentially a new grammar school, the decision reignited an old debate about the value of academically-selective "grammar" schools in England. The intensity…

Using Space to Inspire and Engage Children

ERIC Educational Resources Information Center

Clements, Allan

2015-01-01

The European Space Education Resources Office (ESERO-UK) is a project of the European Space Agency (ESA) and national partners including the Department for Education (DfE), The UK Space Agency (UKSA) and the Science and Technology Facilities Council (STFC). The key objective of the project is to promote space as an exciting inspirational context…

Cereal Box Design: An Interdisciplinary Graphics Activity

ERIC Educational Resources Information Center

Fitzgerald, Mike; Tsosie, Teri

2004-01-01

This article describes cereal box design, an interdisciplinary graphics activity. The cereal box design activity is intriguing both for its simplicity and the resourcefulness that it can generate in young people. It lends itself to a variety of curriculums. It covers both consumerism and Design for the Environment (DfE) concepts broadly and in…

Too many chemicals, too little time: Rapid in silico methods to characterize and predict ADME properties for chemical toxicity and exposure potential

EPA Science Inventory

Evaluating proposed alternative chemical structures to support the design of safer chemicals and products is an important component of EPA's Green Chemistry and Design for the Environment (DfE) Programs. As such, science-based alternatives assessment is essential to support EPA's...

U.S. EPA, Pesticide Product Label, , 11/14/1991

EPA Pesticide Factsheets

2011-04-21

... 0. i~jS-"lu j~!:-;l.)licQt.ivl.1~ uat,.t;;;(.l nUSlUc.t. .:t~, .l~~l ilUu uctowr ~j, 1~~..L 4:"<.(H.iu(.:stih'.,;: dn I'\\lt~rr,~l~' O£lJuu L'id.fe u~nolin'::J ...

Action against Bullying.

ERIC Educational Resources Information Center

Smith, Peter K.; Madsen, Kirsten C.

This poster presentation outlines the work of the DFE Anti-bullying project. In the first part of the poster the results of a large scale survey in the United Kingdom are presented. The results show the extent and nature of bullying. The questionnaire survey was administered to students from 24 schools in and around Sheffield, a northern…

"Old Poems Have Heart": Teenage Students Reading Early Modern Poetry

ERIC Educational Resources Information Center

Naylor, Amanda

2013-01-01

The proposals for the revised National Curriculum in English suggest limiting the pre-twentieth century poetry that GCSE pupils read to "representative Romantic poetry" (Department for Education [DFE], 2013, p. 4). This paper argues that poetry of the early modern period is challenging and enriching study for adolescent pupils and that…

3D facial expression recognition using maximum relevance minimum redundancy geometrical features

NASA Astrophysics Data System (ADS)

Rabiu, Habibu; Saripan, M. Iqbal; Mashohor, Syamsiah; Marhaban, Mohd Hamiruce

2012-12-01

In recent years, facial expression recognition (FER) has become an attractive research area, which besides the fundamental challenges, it poses, finds application in areas, such as human-computer interaction, clinical psychology, lie detection, pain assessment, and neurology. Generally the approaches to FER consist of three main steps: face detection, feature extraction and expression recognition. The recognition accuracy of FER hinges immensely on the relevance of the selected features in representing the target expressions. In this article, we present a person and gender independent 3D facial expression recognition method, using maximum relevance minimum redundancy geometrical features. The aim is to detect a compact set of features that sufficiently represents the most discriminative features between the target classes. Multi-class one-against-one SVM classifier was employed to recognize the seven facial expressions; neutral, happy, sad, angry, fear, disgust, and surprise. The average recognition accuracy of 92.2% was recorded. Furthermore, inter database homogeneity was investigated between two independent databases the BU-3DFE and UPM-3DFE the results showed a strong homogeneity between the two databases.

Sedimentary and atmospheric sources of iron around South Georgia, Southern Ocean: a modelling perspective

NASA Astrophysics Data System (ADS)

Borrione, I.; Aumont, O.; Nielsdóttir, M. C.; Schlitzer, R.

2013-07-01

In high-nutrient low-chlorophyll waters of the western Atlantic sector of the Southern Ocean, an intense phytoplankton bloom is observed annually north of South Georgia, most likely due to an enhanced supply of the limiting micronutrient iron. Shallow sediments and atmospheric dust deposition are believed to be the main iron sources. However, their relative importance is still unclear and in the South Georgia region have yet not been ascertained because iron measurements are very few. In this study, we use austral summer dissolved iron (dFe) data around South Georgia (January and February 2008) with a coupled regional hydrodynamic and biogeochemical model to investigate natural iron fertilization around the island. The biogeochemical component of the model includes an iron cycle, where sediments and dust deposition are the sources of iron to the ocean. The model captures the characteristic flow patterns around South Georgia, hence simulating a large phytoplankton bloom to the north, i.e., downstream, of the island. Modelled dFe concentrations agree well with observations (mean difference and root mean square errors of ~0.02 nM and ~0.81 nM) and form a large plume to the north of the island that extends eastwards for more than 800 km. In agreement with observations, highest dFe concentrations are located along the coast and decrease with distance from the island. Sensitivity tests indicate that most of the iron measured in the main bloom area originates from the coast and the very shallow shelf-sediments (depths < 20 m) while dust deposition plays a minor role, with almost no effects on surface chlorophyll a concentrations. Iron sources such as run-off not represented explicitly in the model, but that likely contribute to the iron plumes observed around South Georgia, are also discussed together with the potential effects their temporal variability may have on the system.

Jarzynski-Type Equalities in Gambling: Role of Information in Capital Growth

NASA Astrophysics Data System (ADS)

Hirono, Yuji; Hidaka, Yoshimasa

2015-11-01

We study the capital growth in gambling with (and without) side information and memory effects. We derive several equalities for gambling, which are of similar form to the Jarzynski equality and its extension to systems with feedback controls. Those relations provide us with new measures to quantify the effects of information on the statistics of capital growth in gambling. We discuss the implications of the equalities and show that they reproduce the known upper bounds of average capital growth rates.

Application of the Social Marketing Model to Unemployment Counseling: A Theoretical Perspective

ERIC Educational Resources Information Center

Englert, Paul; Sommerville, Susannah; Guenole, Nigel

2009-01-01

A. R. Andreasen's (1995) social marketing model (SMM) is applied to structure feedback counseling for individuals who are unemployed. The authors discuss techniques used in commercial marketing and how they are equally applicable to solving societal problems; SMM and its application to social interventions; and structured feedback that moves a…

Silent Policy Feedback through School Choice

ERIC Educational Resources Information Center

Little-Hunt, Catherine Cecchini

2017-01-01

Increasing numbers of Florida parents are withdrawing their children from traditional public schools in highly-rated school districts to enroll them in tuition-free, startup, charter schools. Since not all parents have equal access or are as equally motivated to elect school choice alternatives, the fiscal sustainability of the traditional public…

Evaluation of In Harmony: Year 1. Interim Report

ERIC Educational Resources Information Center

Lord, Pippa; Sharp, Caroline; Dawson, Anneka; Mehta, Palak; White, Richard; Jeffes, Jennifer

2013-01-01

Arts Council England (ACE) commissioned NFER to undertake the national evaluation of the In Harmony social and music education programme 2012-2015. In Harmony is funded by the Department for Education (DfE) and ACE, and is currently being piloted in six areas. The evaluation is investigating the range and extent of impacts on children, families,…

40 CFR 80.1642 - Sampling and testing requirements for producers and importers of denatured fuel ethanol and other...

Code of Federal Regulations, 2014 CFR

2014-07-01

... producers and importers of denatured fuel ethanol and other oxygenates for use by oxygenate blenders. 80... requirements for producers and importers of denatured fuel ethanol and other oxygenates for use by oxygenate blenders. Beginning January 1, 2017, producers and importers of denatured fuel ethanol (DFE) and other...

40 CFR 80.1610 - Standards and requirements for producers and importers of denatured fuel ethanol and other...

Code of Federal Regulations, 2014 CFR

2014-07-01

... producers and importers of denatured fuel ethanol and other oxygenates designated for use in transportation... requirements for producers and importers of denatured fuel ethanol and other oxygenates designated for use in transportation fuel. Beginning January 1, 2017, producers and importers of denatured fuel ethanol (DFE) or other...

Earth Science: It's All about the Processes

ERIC Educational Resources Information Center

King, Chris

2013-01-01

Readers of the draft new English primary science curriculum (DfE, 2012) might be concerned to see that there is much more detail on the Earth science content than previously in the United Kingdom. In this article, Chris King, a professor of Earth Science Education at Keele University and Director of the Earth Science Education Unit (ESEU),…

Cereal Box Design: An Interdisciplinary Graphics Activity

ERIC Educational Resources Information Center

Fitzgerald, Mike; Tsosie, Teri

2012-01-01

The cereal box design activity is intriguing both for its simplicity and the resourcefulness that it can generate in young people. Also, it lends itself to a variety of curriculums. It covers both consumerism and Design for the Environment (DfE) concepts broadly and in depth. The activity introduces a wide range of topics. They include graphic…

78 FR 38029 - Information Collection Request Submitted to OMB for Review and Approval; Comment Request; EPA's...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-25

... Submitted to OMB for Review and Approval; Comment Request; EPA's Design for the Environment Formulator... Environment Formulator Product Recognition Program'' (EPA ICR No. 2302.02, OMB Control No. 2070-0178), to the..., visit http://www.epa.gov/dockets . Abstract: EPA's Design for the Environment (DfE) Formulator Product...

Analysis of the faster-than-Nyquist optimal linear multicarrier system

NASA Astrophysics Data System (ADS)

Marquet, Alexandre; Siclet, Cyrille; Roque, Damien

2017-02-01

Faster-than-Nyquist signalization enables a better spectral efficiency at the expense of an increased computational complexity. Regarding multicarrier communications, previous work mainly relied on the study of non-linear systems exploiting coding and/or equalization techniques, with no particular optimization of the linear part of the system. In this article, we analyze the performance of the optimal linear multicarrier system when used together with non-linear receiving structures (iterative decoding and direct feedback equalization), or in a standalone fashion. We also investigate the limits of the normality assumption of the interference, used for implementing such non-linear systems. The use of this optimal linear system leads to a closed-form expression of the bit-error probability that can be used to predict the performance and help the design of coded systems. Our work also highlights the great performance/complexity trade-off offered by decision feedback equalization in a faster-than-Nyquist context. xml:lang="fr"

Suppression of Spontaneous Gas Oscillations by Acoustic Self-Feedback

NASA Astrophysics Data System (ADS)

Biwa, Tetsushi; Sawada, Yoshiki; Hyodo, Hiroaki; Kato, Soichiro

2016-10-01

This paper demonstrates a method of acoustical self-feedback to suppress spontaneous gas oscillations such as those observed in combustors of gas-turbine engines. Whereas a conventional feedback system consists of electromechanical devices, the present method achieves acoustical self-feedback with a hollow tube that connects two positions of the oscillation system. A model oscillator of combustion-driven gas oscillations is designed and built to demonstrate the applicability of the self-feedback concept. Stability analysis through measurements of Q values (quality factor) of oscillations shows that the desired delay time and gain are obtained when the tube length is equal to the odd integer times half the wavelength of the anticipated acoustic oscillations.

Differential Effectiveness of Electromyograph Feedback, Verbal Relaxation Instructions, and Medication Placebo with Tension Headaches

ERIC Educational Resources Information Center

Cox, Daniel J.; And Others

1975-01-01

Adults with chronic tension headaches were assigned to auditory electromyograph (EMG) feedback (N=9), to progressive relaxation (N=9), and to placebo treatment (N=9). Data indicated that biofeedback and verbal relaxation instructions were equally superior to the medicine placebo on all measured variables in the direction of clinical improvement,…

A model-based investigation of manipulator characteristics and pilot/vehicle performance

NASA Technical Reports Server (NTRS)

Hess, R. A.

1983-01-01

Hess (1978, 1981) has introduced and discussed a structural model of the human pilot in which proprioceptive feedback plays a fundamental role in determining pilot equalization characteristics. It is pointed out that, on account of the feedback structure, this model may provide more insight into the effects of certain manipulator characteristics upon pilot equalization than would other modeling approaches. The model is briefly discussed, and an outline is presented concerning some of the implications of the model structure regarding the manipulator characteristics. Attention is given to some specific empirical examples of manipulator effects involving glide slope tracking in STOL aircraft, taking into account an employment of the model as a theoretical framework.

To Promote, or Not to Promote Fundamental British Values? Teachers' Standards, Diversity and Teacher Education

ERIC Educational Resources Information Center

Elton-Chalcraft, Sally; Lander, Vini; Revell, Lynn; Warner, Diane; Whitworth, Linda

2017-01-01

In this article we seek to problematize the presence of the requirement within the teachers' standards (DfE, 2012), that they "should not undermine fundamental British values" in the context of initial teacher education in England. The inclusion of this statement within the teachers' code of conduct has made its way from the…

More? Great? Childcare? A Discourse Analysis of Two Recent Social Policy Documents Relating to the Care and Education of Young Children in England

ERIC Educational Resources Information Center

Wild, Mary; Silberfeld, Carolyn; Nightingale, Beverley

2015-01-01

This paper considers the overt and covert discourses in two contemporary policy documents in England and Wales, "The Nutbrown Review: Foundations for Quality" ([DfE] Department for Education Department for Education. 2012. "The Nutbrown Review: Foundations for Quality: The Independent Review of Early Education and Childcare…

The Complex Learning Difficulties and Disabilities Research Project: Developing Meaningful Pathways to Personalised Learning. Executive Summary

ERIC Educational Resources Information Center

Schools Network, 2011

2011-01-01

The Specialist Schools and Academies Trust (SSAT) was commissioned by the Department for Education (DfE) to research ways to improve outcomes for children and young people with the most complex educational needs and disabilities through the development of evidence-based teaching and learning strategies. The programme of research brought together a…

Approaches to Increasing the Competence and Confidence of Student Teachers to Teach Music in Primary Schools

ERIC Educational Resources Information Center

Hennessy, Sarah

2017-01-01

The National Plan for Music (DfE (Department for Education). 2011. The "Importance of Music: a National Plan for Music Education." https://www.gov.uk/government/publications/the-importance-of-music-a-national-plan-for-music-education.) reflected the need for increasing the numbers of primary class teachers able to teach music and of…

"I Will Be 'Fighting' Even More for Pupils with SEN": SENCOs' Role Predictions in the Changing English Policy Context

ERIC Educational Resources Information Center

Pearson, Sue; Mitchell, Rafael; Rapti, Maria

2015-01-01

The Coalition Government's "Green Paper" (DfE 2011) proposes a systemic overhaul of services for pupils with special educational needs in England, with increased parental choice of provision and "sharper accountability" (p. 67) in schools. Deadlines for various stages of this reform have not been met, and its final nature…

Traditional Tales and Imaginary Contexts in Primary Design and Technology: A Case Study

ERIC Educational Resources Information Center

McLain, Matt; McLain, Mel; Tsai, Jess; Martin, Mike; Bell, Dawne; Wooff, David

2017-01-01

Working with contexts is a key component to design and technology activity and education. The most recent iteration of the national curriculum programme of study for design and technology, in England, sets out that children between the ages of 5 and 7 "should work in a range of relevant contexts" (DfE, 2013, p.193); suggested contexts…

Recruitment, Retention and the Workload Challenge: A Critique of the Government Response

ERIC Educational Resources Information Center

Quicke, John

2018-01-01

Various surveys have confirmed that there is a crisis of recruitment and retention of teachers in schools. This article examines the government response to this crisis, in particular to what is commonly cited as the main cause--unmanageable workloads. What it describes as the workload challenge has certainly not been ignored by the DfE, which in…

The use of third-party review to reduce health and environmental hazards from surfactants and cleaning products in the janitorial industry.

PubMed

Okumura, Kazuhiro

2009-05-01

The demand for environmentally preferable products is increasing in the area of Institutional and Industrial (I&I) cleaners. The GreenBlue Institute (GreenBlue) and U.S. Environmental Protection Agency's (U.S. EPA's) Design for Environment (DfE) launched two programs to review surfactant ingredients and final cleaning products, with the National Sanitation Foundation (NSF) conducting third-party reviews. The Local Hazardous Waste Management Program (LHWMP) in King County, Washington, has a strategic goal to reduce the risk of exposure of hazardous chemicals to vulnerable populations such as janitorial workers. This report summarizes the NSF partnership with GreenBlue, CleanGredients, and U.S. EPA's DfE to perform third-party reviews of cleaning product ingredients and its relevance to LHWMP's interest in reducing risks to workers in the janitorial industry. Due to information barriers, workers in the janitorial industry are at risk daily to these hazardous chemicals. The surfactant and formulator review program will make positive contributions towards the reduction of toxic chemical exposure to the employees of the janitorial industry. With proper communication and an increased use of less toxic cleaners, exposures to vulnerable populations can be reduced.

Food matrix and cooking process affect mineral bioaccessibility of enteral nutrition formulas.

PubMed

Galán, María Gimena; Drago, Silvina Rosa

2014-02-01

When enteral formulas (EF) are administered orally as a supplement to the normal diet, they are often mixed with conventional foods or included in recipes in order to seek new flavors and textures and avoid monotony. The aims of this work were to study the bioaccessibility of Fe, Zn and Ca from commercial EF and the impact upon their incorporation into sweet preparations. Twenty commercial EF, before and after inclusion in sweet food (rice pudding, RP; banana smoothie, BS; tea, T; chocolate dessert, CD) were evaluated regarding Fe, Zn and Ca dialyzability (%DFe , %DZn , %DCa ) as an estimator of mineral bioaccessibility. Fe, Zn and Ca dialyzability from EF was variable and generally low. Heating during EF-sweet food preparation (T and CD) lowered values to 44.1 %DFe , possibly due to degradation of vitamin C, and 52.7 %DZn and 25.3 %DCa , due to the interaction with food components. EF and EF-sweet foods did not represent a good supply of Fe, Zn and Ca as recommended. This study demonstrated how the bioaccessibility of these minerals is affected by the food matrix in which EF is included as well as heating during food preparation. © 2013 Society of Chemical Industry.

The Irony of Iron – Biogenic Iron Oxides as an Iron Source to the Ocean

PubMed Central

Emerson, David

2016-01-01

Primary productivity in at least a third of the sunlit open ocean is thought to be iron-limited. Primary sources of dissolved iron (dFe) to the ocean are hydrothermal venting, flux from the sediments along continental margins, and airborne dust. This article provides a general review of sources of hydrothermal and sedimentary iron to the ocean, and speculates upon the role that iron-cycling microbes play in controlling iron dynamics from these sources. Special attention is paid to iron-oxidizing bacteria (FeOB) that live by oxidizing iron and producing biogenic iron oxides as waste products. The presence and ubiquity of FeOB both at hydrothermal systems and in sediments is only beginning to be appreciated. The biogenic oxides they produce have unique properties that could contribute significantly to the dynamics of dFe in the ocean. Changes in the physical and chemical characteristics of the ocean due to climate change and ocean acidification will undoubtedly impact the microbial iron cycle. A better understanding of the contemporary role of microbes in the iron cycle will help in predicting how these changes could ultimately influence marine primary productivity. PMID:26779157

Effect of light-dark cycles on hydrogen and poly-β-hydroxybutyrate production by a photoheterotrophic culture and Rhodobacter capsulatus using a dark fermentation effluent as substrate.

PubMed

Montiel Corona, Virginia; Le Borgne, Sylvie; Revah, Sergio; Morales, Marcia

2017-02-01

A Rhodobacter capsulatus strain and a photoheterotrophic culture (IZT) were cultivated to produce hydrogen under different light-dark cycles. A dark fermentation effluent (DFE) was used as substrate. It was found that IZT culture had an average cumulative hydrogen production (Paccum H 2 ) of 1300±43mLH 2 L -1 under continuous illumination and light-dark cycles of 30 or 60min. In contrast, R. capsulatus reduced its Paccum H 2 by 20% under 30:30min light-dark cycles, but tripled its poly-β-hydroxybutyrate (PHB) content (308±2mgPHB gdw -1 ) compared to continuous illumination. The highest PHB content by IZT culture was 178±10mgPHB gdw -1 under 15:15min light-dark cycles. PCR-DGGE analysis revealed that the IZT culture was mainly composed of Rhodopseudomonas palustris identified with high nucleotide similarity (99%). The evaluated cultures might be used for hydrogen and PHB production. They might provide energy savings by using light-dark cycles and DFE valorization. Copyright © 2016 Elsevier Ltd. All rights reserved.

Chlorella vulgaris Attenuates Dermatophagoides Farinae-Induced Atopic Dermatitis-Like Symptoms in NC/Nga Mice

PubMed Central

Kang, Heerim; Lee, Chang Hyung; Kim, Jong Rhan; Kwon, Jung Yeon; Seo, Sang Gwon; Han, Jae Gab; Kim, Byung Gon; Kim, Jong-Eun; Lee, Ki Won

2015-01-01

Atopic dermatitis (AD) is a chronic and inflammatory skin disease that can place a significant burden on quality of life for patients. AD most frequently appears under the age of six and although its prevalence is increasing worldwide, therapeutic treatment options are limited. Chlorella vulgaris (CV) is a species of the freshwater green algae genus chlorella, and has been reported to modulate allergy-inducible factors when ingested. Here, we examined the effect of CV supplementation on AD-like symptoms in NC/Nga mice. CV was orally administrated for six weeks while AD-like symptoms were induced via topical application of Dermatophagoides farinae extract (DFE). CV treatment reduced dermatitis scores, epidermal thickness, and skin hydration. Histological analysis also revealed that CV treatment reduced DFE-induced eosinophil and mast cell infiltration into the skin, while analysis of serum chemokine levels indicated that CV treatment downregulated thymus- and activation-regulated chemokine (TARC) and macrophage-derived chemokine (MDC) levels. In addition, CV treatment downregulated mRNA expression levels of IL-4 and IFN-γ. Taken together, these results suggest that CV extract may have potential as a nutraceutical ingredient for the prevention of AD. PMID:26404252

Are Success and Failure Experiences Equally Motivational? An Investigation of Regulatory Focus and Feedback

ERIC Educational Resources Information Center

Shu, Tse-Mei; Lam, Shui-fong

2011-01-01

The present study extended regulatory focus theory (Idson & Higgins, 2000) to an educational setting and attempted to identify individuals with high motivation after both success and failure feedback. College students in Hong Kong (N = 180) participated in an experiment with a 2 promotion focus (high vs. low) x 2 prevention focus (high vs.…

Equalization for a page-oriented optical memory system

NASA Astrophysics Data System (ADS)

Trelewicz, Jennifer Q.; Capone, Jeffrey

1999-11-01

In this work, a method of decision-feedback equalization is developed for a digital holographic channel that experiences moderate-to-severe imaging errors. Decision feedback is utilized, not only where the channel is well-behaved, but also near the edges of the camera grid that are subject to a high degree of imaging error. In addition to these effects, the channel is worsened by typical problems of holographic channels, including non-uniform illumination, dropouts, and stuck bits. The approach described in this paper builds on established methods for performing trained and blind equalization on time-varying channels. The approach is tested on experimental data sets. On most of these data sets, the method of equalization described in this work delivers at least an order of magnitude improvement in bit-error rate (BER) before error-correction coding (ECC). When ECC is introduced, the approach is able to recover stored data with no errors for many of the tested data sets. Furthermore, a low BER was maintained even over a range of small alignment perturbations in the system. It is believed that this equalization method can allow cost reductions to be made in page-memory systems, by allowing for a larger image area per page or less complex imaging components, without sacrificing the low BER required by data storage applications.

Log amplifier with pole-zero compensation

DOEpatents

Brookshier, William

1987-01-01

A logarithmic amplifier circuit provides pole-zero compensation for improved stability and response time over 6-8 decades of input signal frequency. The amplifier circuit includes a first operational amplifier with a first feedback loop which includes a second, inverting operational amplifier in a second feedback loop. The compensated output signal is provided by the second operational amplifier with the log elements, i.e., resistors, and the compensating capacitors in each of the feedback loops having equal values so that each break point or pole is offset by a compensating break point or zero.

Effect of Rayleigh-scattering distributed feedback on multiwavelength Raman fiber laser generation.

PubMed

El-Taher, A E; Harper, P; Babin, S A; Churkin, D V; Podivilov, E V; Ania-Castanon, J D; Turitsyn, S K

2011-01-15

We experimentally demonstrate a Raman fiber laser based on multiple point-action fiber Bragg grating reflectors and distributed feedback via Rayleigh scattering in an ~22-km-long optical fiber. Twenty-two lasing lines with spacing of ~100 GHz (close to International Telecommunication Union grid) in the C band are generated at the watt level. In contrast to the normal cavity with competition between laser lines, the random distributed feedback cavity exhibits highly stable multiwavelength generation with a power-equalized uniform distribution, which is almost independent on power.

Lossless Brownian Information Engine

NASA Astrophysics Data System (ADS)

Paneru, Govind; Lee, Dong Yun; Tlusty, Tsvi; Pak, Hyuk Kyu

2018-01-01

We report on a lossless information engine that converts nearly all available information from an error-free feedback protocol into mechanical work. Combining high-precision detection at a resolution of 1 nm with ultrafast feedback control, the engine is tuned to extract the maximum work from information on the position of a Brownian particle. We show that the work produced by the engine achieves a bound set by a generalized second law of thermodynamics, demonstrating for the first time the sharpness of this bound. We validate a generalized Jarzynski equality for error-free feedback-controlled information engines.

Lossless Brownian Information Engine.

PubMed

Paneru, Govind; Lee, Dong Yun; Tlusty, Tsvi; Pak, Hyuk Kyu

2018-01-12

We report on a lossless information engine that converts nearly all available information from an error-free feedback protocol into mechanical work. Combining high-precision detection at a resolution of 1 nm with ultrafast feedback control, the engine is tuned to extract the maximum work from information on the position of a Brownian particle. We show that the work produced by the engine achieves a bound set by a generalized second law of thermodynamics, demonstrating for the first time the sharpness of this bound. We validate a generalized Jarzynski equality for error-free feedback-controlled information engines.

Analytically tractable climate-carbon cycle feedbacks under 21st century anthropogenic forcing

NASA Astrophysics Data System (ADS)

Lade, Steven J.; Donges, Jonathan F.; Fetzer, Ingo; Anderies, John M.; Beer, Christian; Cornell, Sarah E.; Gasser, Thomas; Norberg, Jon; Richardson, Katherine; Rockström, Johan; Steffen, Will

2018-05-01

Changes to climate-carbon cycle feedbacks may significantly affect the Earth system's response to greenhouse gas emissions. These feedbacks are usually analysed from numerical output of complex and arguably opaque Earth system models. Here, we construct a stylised global climate-carbon cycle model, test its output against comprehensive Earth system models, and investigate the strengths of its climate-carbon cycle feedbacks analytically. The analytical expressions we obtain aid understanding of carbon cycle feedbacks and the operation of the carbon cycle. Specific results include that different feedback formalisms measure fundamentally the same climate-carbon cycle processes; temperature dependence of the solubility pump, biological pump, and CO2 solubility all contribute approximately equally to the ocean climate-carbon feedback; and concentration-carbon feedbacks may be more sensitive to future climate change than climate-carbon feedbacks. Simple models such as that developed here also provide workbenches for simple but mechanistically based explorations of Earth system processes, such as interactions and feedbacks between the planetary boundaries, that are currently too uncertain to be included in comprehensive Earth system models.

Class Size and Education in England Evidence Report. Research Report. DFE-RR169

ERIC Educational Resources Information Center

Department for Education, 2011

2011-01-01

This report gives an overview of the existing evidence base on class size and education in England. In particular, it considers how class sizes have changed over time; the impact of the increase in birth rate on pupil numbers and how this could affect the teacher requirement and class sizes; and the impact of class size on educational outcomes.…

Are We Nearly There Yet? Progress, Issues, and Possible Next Steps for a Self-Improving School System. Inaugural Professorial Lecture

ERIC Educational Resources Information Center

Greany, Toby

2014-01-01

The DfE's 2010 white paper "The Importance of Teaching" set out the Coalition's aim to "create a school system which is self-improving". In this inaugural lecture, Toby Greany assesses progress to date and the Coalition Government's approach to developing a self-improving system. He argues that the Coalition is following at…

Educator Perceptions of Children Who Present with Social, Emotional and Behavioural Difficulties: A Literature Review with Implications for Recent Educational Policy in England and Internationally

ERIC Educational Resources Information Center

Armstrong, David

2014-01-01

In support of their recommendations, recent policy pronouncements in England on behaviour (DFE (Department for Education). 2010. "The Importance of Teaching-The Schools White Paper". London: TSO) and on reform of special educational needs and disabilities make reference, respectively, to educator perceptions of poor behaviour by children…

Review of the National Curriculum in England: Report on Subject Breadth in International Jurisdictions. Research Report. DFE-RR178a

ERIC Educational Resources Information Center

Department for Education, 2011

2011-01-01

To support the review of the National Curriculum, the National Foundation for Educational Research (NFER) was commissioned by the Department for Education in the spring of 2011 to produce a report detailing curricular arrangements in a number of high-performing educational jurisdictions. The principal source of information for this report has been…

Growing Musicians in English Secondary Schools at Key Stage 3 (Age 11-14)

ERIC Educational Resources Information Center

Dalladay, Christopher

2017-01-01

The National Curriculum for Music in England at Key Stage 3 (KS3; age 11-14) declares its purpose that pupils should be inspired to "develop a love of music and their talent as musicians" (DfE, 2013: KS3 Music). The Office for Standards in Education (Ofsted) have criticised secondary schools for a lack of progress in the musical…

Enhancing the learning of sport skills through external-focus feedback.

PubMed

Wulf, Gabriele; McConnel, Nathan; Gärtner, Matthias; Schwarz, Andreas

2002-06-01

The authors examined how the effectiveness of feedback for the learning of complex motor skills is affected by the focus of attention it induces. The feedback referred specifically either to body movements (internal focus) or to movement effects (external focus). In Experiment 1, groups of novices and advanced volleyball players (N = 48) practiced "tennis" serves under internal-focus or external-focus feedback conditions in a 2 (expertise) x 2 (feedback type) design. Type of feedback did not differentially affect movement quality, but external-focus feedback resulted in greater accuracy of the serves than internal-focus feedback during both practice and retention, independent of the level of expertise. In Experiment 2, the effects of relative feedback frequency as a function of attentional focus were examined. A 2 (feedback frequency: 100% vs. 33%) x 2 (feedback type) design was used. Experienced soccer players (N = 52) were required to shoot lofted passes at a target. External-focus feedback resulted in greater accuracy than internal-focus feedback did. In addition, reduced feedback frequency was beneficial under internal-focus feedback conditions, whereas 100% and 33% feedback were equally effective under external-focus conditions. The results demonstrate the effectiveness of effect-related, as opposed to movement-related, feedback and also suggest that there is a need to revise current views regarding the role of feedback for motor learning.

Improving the efficiency of cognitive-behavioural therapy by using formal client feedback.

PubMed

Janse, Pauline D; De Jong, Kim; Van Dijk, Maarten K; Hutschemaekers, Giel J M; Verbraak, Marc J P M

2017-09-01

Feedback from clients on their view of progress and the therapeutic relationship can improve effectiveness and efficiency of psychological treatments in general. However, what the added value is of client feedback specifically within cognitive-behavioural therapy (CBT), is not known. Therefore, the extent to which the outcome of CBT can be improved is investigated by providing feedback from clients to therapists using the Outcome Rating Scale (ORS) and Session Rating Scale (SRS). Outpatients (n = 1006) of a Dutch mental health organization either participated in the "treatment as usual" (TAU) condition, or in Feedback condition of the study. Clients were invited to fill in the ORS and SRS and in the Feedback condition therapists were asked to frequently discuss client feedback. Outcome on the SCL-90 was only improved specifically with mood disorders in the Feedback condition. Also, in the Feedback condition, in terms of process, the total number of required treatment sessions was on average two sessions fewer. Frequently asking feedback from clients using the ORS/SRS does not necessarily result in a better treatment outcome in CBT. However, for an equal treatment outcome significantly fewer sessions are needed within the Feedback condition, thus improving efficiency of CBT.

Acceleration of Image Segmentation Algorithm for (Breast) Mammogram Images Using High-Performance Reconfigurable Dataflow Computers

PubMed Central

Filipovic, Nenad D.

2017-01-01

Image segmentation is one of the most common procedures in medical imaging applications. It is also a very important task in breast cancer detection. Breast cancer detection procedure based on mammography can be divided into several stages. The first stage is the extraction of the region of interest from a breast image, followed by the identification of suspicious mass regions, their classification, and comparison with the existing image database. It is often the case that already existing image databases have large sets of data whose processing requires a lot of time, and thus the acceleration of each of the processing stages in breast cancer detection is a very important issue. In this paper, the implementation of the already existing algorithm for region-of-interest based image segmentation for mammogram images on High-Performance Reconfigurable Dataflow Computers (HPRDCs) is proposed. As a dataflow engine (DFE) of such HPRDC, Maxeler's acceleration card is used. The experiments for examining the acceleration of that algorithm on the Reconfigurable Dataflow Computers (RDCs) are performed with two types of mammogram images with different resolutions. There were, also, several DFE configurations and each of them gave a different acceleration value of algorithm execution. Those acceleration values are presented and experimental results showed good acceleration. PMID:28611851

The Role of Inertia in Modeling Decisions from Experience with Instance-Based Learning

PubMed Central

Dutt, Varun; Gonzalez, Cleotilde

2012-01-01

One form of inertia is the tendency to repeat the last decision irrespective of the obtained outcomes while making decisions from experience (DFE). A number of computational models based upon the Instance-Based Learning Theory, a theory of DFE, have included different inertia implementations and have shown to simultaneously account for both risk-taking and alternations between alternatives. The role that inertia plays in these models, however, is unclear as the same model without inertia is also able to account for observed risk-taking quite well. This paper demonstrates the predictive benefits of incorporating one particular implementation of inertia in an existing IBL model. We use two large datasets, estimation and competition, from the Technion Prediction Tournament involving a repeated binary-choice task to show that incorporating an inertia mechanism in an IBL model enables it to account for the observed average risk-taking and alternations. Including inertia, however, does not help the model to account for the trends in risk-taking and alternations over trials compared to the IBL model without the inertia mechanism. We generalize the two IBL models, with and without inertia, to the competition set by using the parameters determined in the estimation set. The generalization process demonstrates both the advantages and disadvantages of including inertia in an IBL model. PMID:22685443

The role of inertia in modeling decisions from experience with instance-based learning.

PubMed

Dutt, Varun; Gonzalez, Cleotilde

2012-01-01

One form of inertia is the tendency to repeat the last decision irrespective of the obtained outcomes while making decisions from experience (DFE). A number of computational models based upon the Instance-Based Learning Theory, a theory of DFE, have included different inertia implementations and have shown to simultaneously account for both risk-taking and alternations between alternatives. The role that inertia plays in these models, however, is unclear as the same model without inertia is also able to account for observed risk-taking quite well. This paper demonstrates the predictive benefits of incorporating one particular implementation of inertia in an existing IBL model. We use two large datasets, estimation and competition, from the Technion Prediction Tournament involving a repeated binary-choice task to show that incorporating an inertia mechanism in an IBL model enables it to account for the observed average risk-taking and alternations. Including inertia, however, does not help the model to account for the trends in risk-taking and alternations over trials compared to the IBL model without the inertia mechanism. We generalize the two IBL models, with and without inertia, to the competition set by using the parameters determined in the estimation set. The generalization process demonstrates both the advantages and disadvantages of including inertia in an IBL model.

Acceleration of Image Segmentation Algorithm for (Breast) Mammogram Images Using High-Performance Reconfigurable Dataflow Computers.

PubMed

Milankovic, Ivan L; Mijailovic, Nikola V; Filipovic, Nenad D; Peulic, Aleksandar S

2017-01-01

Image segmentation is one of the most common procedures in medical imaging applications. It is also a very important task in breast cancer detection. Breast cancer detection procedure based on mammography can be divided into several stages. The first stage is the extraction of the region of interest from a breast image, followed by the identification of suspicious mass regions, their classification, and comparison with the existing image database. It is often the case that already existing image databases have large sets of data whose processing requires a lot of time, and thus the acceleration of each of the processing stages in breast cancer detection is a very important issue. In this paper, the implementation of the already existing algorithm for region-of-interest based image segmentation for mammogram images on High-Performance Reconfigurable Dataflow Computers (HPRDCs) is proposed. As a dataflow engine (DFE) of such HPRDC, Maxeler's acceleration card is used. The experiments for examining the acceleration of that algorithm on the Reconfigurable Dataflow Computers (RDCs) are performed with two types of mammogram images with different resolutions. There were, also, several DFE configurations and each of them gave a different acceleration value of algorithm execution. Those acceleration values are presented and experimental results showed good acceleration.

The sensitivity of primary productivity to intra-seasonal mixed layer variability in the sub-Antarctic Zone of the Atlantic Ocean

NASA Astrophysics Data System (ADS)

Joubert, W. R.; Swart, S.; Tagliabue, A.; Thomalla, S. J.; Monteiro, P. M. S.

2014-03-01

The seasonal cycle of primary productivity is impacted by seasonal and intra-seasonal dynamics of the mixed layer through the changing balance between mixing and buoyancy forcing, which regulates nutrient supply and light availability. Of particular recent interest is the role of synoptic scale events in supplying nutrients, particularly iron, to the euphotic zone in the Sub Antarctic Zone (SAZ), where phytoplankton blooms occur throughout summer. In this study, we present high resolution measurements of net community production (NCP) constrained by ΔO2/Ar ratios, and mixed layer depth (MLD) in the Atlantic SAZ. We found a non-linear relationship between NCP and MLD, with the highest and most variable NCP observed in shallow MLDs (< 45 m). We propose that NCP variability in the SAZ may be driven by alternating states of synoptic-scale deepening of the mixed layer, leading to the entrainment of iron (dFe), followed by restratification, allowing rapid growth in an iron replete, high light environment. Synoptic iron fluxes into the euphotic zone based on water column dFe profiles and high resolution glider MLD data, reveal a potentially significant contribution of "new iron" which could sustain NCP throughout summer. Future process studies will help elaborate these findings further.

A Constant Envelope OFDM Implementation on GNU Radio

DTIC Science & Technology

2015-02-02

more advanced schemes like Decision Feedback Equalization or Turbo Equalization must be implemented to avoid the noise enhancement that all linear...block is coded in C++, and uses the phase unwrapping algorithm similar to MATLABs unwrap() function. To avoid false wraps propagating throughout the...outperform the real-time GNU radio implementation at higher SNR’s. While the unequalized experiment with the Matlab processor usually stayed within 5

Adaptive Reception for Underwater Communications

DTIC Science & Technology

2011-06-01

Experimental results prove the effectiveness of the receiver. 14. SUBJECT TERMS Underwater acoustic communications, adaptive algorithms , Kalman filter...the update algorithm design and the value of the spatial diversity are addressed. In this research, an adaptive multichannel equalizer made up of a...for the time-varying nature of the channel is to use an Adaptive Decision Feedback Equalizer based on either the RLS or LMS algorithm . Although this

Diagnosis of Middle Atmosphere Climate Sensitivity by the Climate Feedback Response Analysis Method

NASA Technical Reports Server (NTRS)

Zhu, Xun; Yee, Jeng-Hwa; Cai, Ming; Swartz, William H.; Coy, Lawrence; Aquila, Valentina; Talaat, Elsayed R.

2014-01-01

We present a new method to diagnose the middle atmosphere climate sensitivity by extending the Climate Feedback-Response Analysis Method (CFRAM) for the coupled atmosphere-surface system to the middle atmosphere. The Middle atmosphere CFRAM (MCFRAM) is built on the atmospheric energy equation per unit mass with radiative heating and cooling rates as its major thermal energy sources. MCFRAM preserves the CFRAM unique feature of an additive property for which the sum of all partial temperature changes due to variations in external forcing and feedback processes equals the observed temperature change. In addition, MCFRAM establishes a physical relationship of radiative damping between the energy perturbations associated with various feedback processes and temperature perturbations associated with thermal responses. MCFRAM is applied to both measurements and model output fields to diagnose the middle atmosphere climate sensitivity. It is found that the largest component of the middle atmosphere temperature response to the 11-year solar cycle (solar maximum vs. solar minimum) is directly from the partial temperature change due to the variation of the input solar flux. Increasing CO2 always cools the middle atmosphere with time whereas partial temperature change due to O3 variation could be either positive or negative. The partial temperature changes due to different feedbacks show distinctly different spatial patterns. The thermally driven globally averaged partial temperature change due to all radiative processes is approximately equal to the observed temperature change, ranging from 0.5 K near 70 km from the near solar maximum to the solar minimum.

Time skewing and amplitude nonlinearity mitigation by feedback equalization for 56 Gbps VCSEL-based PAM-4 links

NASA Astrophysics Data System (ADS)

You, Yue; Zhang, Wenjia; Sun, Lin; Du, Jiangbing; Liang, Chenyu; Yang, Fan; He, Zuyuan

2018-03-01

The vertical cavity surface emitting laser (VCSEL)-based multimode optical transceivers enabled by pulse amplitude modulation (PAM)-4 will be commercialized in near future to meet the 400-Gbps standard short reach optical interconnects. It is still challenging to achieve over 56/112-Gbps with the multilevel signaling as the multimode property of the device and link would introduce the nonlinear temporal response for the different levels. In this work, we scrutinize the distortions that relates to the multilevel feature of PAM-4 modulation, and propose an effective feedback equalization scheme for 56-Gbps VCSEL-based PAM-4 optical interconnects system to mitigate the distortions caused by eye timing-skew and nonlinear power-dependent noise. Level redistribution at Tx side is theoretically modeled and constructed to achieve equivalent symbol error ratios (SERs) of four levels and improved BER performance. The cause of the eye skewing and the mitigation approach are also simulated at 100-Gbps and experimentally investigated at 56-Gbps. The results indicate more than 2-dB power penalty improvement has been achieved by using such a distortion aware equalizer.

Data Analysis for Rotationally Resolved Spectra: A Simulated Annealing Approach

DTIC Science & Technology

1992-05-29

Table V. Expe rimental Data PSA was used to analyze high resolution infrared spectra of 2- fluoroethanol (2FE) and difluoroethane (DFE). Although the...does not inhere in the model used to calculate spectra, so the match to the experimental spectrum is not ideal. 8. PSA optimization of Difluoroethane ...A) The experimental spectrum of Difluoroethane . B) The spectrum generated from the starting state given to PSA. C) The spectrum generated from the

Engineer Professional Development Study

DTIC Science & Technology

1980-05-01

the 1980’s. Although no specific data is available, sensings gathered during field interviews and through informal questionnaires at large gatherings...8C21 officers at six years of service for early 󈧭 introduction into the engineer environment. 27 • - ,,m•,•,•,•.e, ,•q•,_: ......... 2...reluctance of quality officers to seuk assig •ments there. 30 b. Increase the number of slots that must be filled in the DFE area at the captain and

How Important Is the Assessment of Practical Work? An Opinion Piece on the New Biology A-Level from BERG

ERIC Educational Resources Information Center

Journal of Biological Education, 2014

2014-01-01

As education in England emerges from a major curriculum review (DfE 2013), the next few years will see significant changes in what is taught in schools and how this is assessed. As a core subject, under the current proposals, all students, from the beginning of primary school until age 16, will study science in some detail. Biology is an exciting,…

Servo control booster system for minimizing following error

DOEpatents

Wise, W.L.

1979-07-26

A closed-loop feedback-controlled servo system is disclosed which reduces command-to-response error to the system's position feedback resolution least increment, ..delta..S/sub R/, on a continuous real-time basis, for all operational times of consequence and for all operating speeds. The servo system employs a second position feedback control loop on a by exception basis, when the command-to-response error greater than or equal to ..delta..S/sub R/, to produce precise position correction signals. When the command-to-response error is less than ..delta..S/sub R/, control automatically reverts to conventional control means as the second position feedback control loop is disconnected, becoming transparent to conventional servo control means. By operating the second unique position feedback control loop used herein at the appropriate clocking rate, command-to-response error may be reduced to the position feedback resolution least increment. The present system may be utilized in combination with a tachometer loop for increased stability.

Learning Rate Updating Methods Applied to Adaptive Fuzzy Equalizers for Broadband Power Line Communications

NASA Astrophysics Data System (ADS)

Ribeiro, Moisés V.

2004-12-01

This paper introduces adaptive fuzzy equalizers with variable step size for broadband power line (PL) communications. Based on delta-bar-delta and local Lipschitz estimation updating rules, feedforward, and decision feedback approaches, we propose singleton and nonsingleton fuzzy equalizers with variable step size to cope with the intersymbol interference (ISI) effects of PL channels and the hardness of the impulse noises generated by appliances and nonlinear loads connected to low-voltage power grids. The computed results show that the convergence rates of the proposed equalizers are higher than the ones attained by the traditional adaptive fuzzy equalizers introduced by J. M. Mendel and his students. Additionally, some interesting BER curves reveal that the proposed techniques are efficient for mitigating the above-mentioned impairments.

Precise measurement of Fe isotopes in marine samples by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS).

PubMed

de Jong, Jeroen; Schoemann, Véronique; Tison, Jean-Louis; Becquevort, Sylvie; Masson, Florence; Lannuzel, Delphine; Petit, Jérôme; Chou, Lei; Weis, Dominique; Mattielli, Nadine

2007-04-18

A novel analytical technique for isotopic analysis of dissolved and particulate iron (Fe) from various marine environments is presented in this paper. It combines coprecipitation of dissolved Fe (DFe) samples with Mg(OH)(2), and acid digestion of particulate Fe (PFe) samples with double pass chromatographic separation. Isotopic data were obtained using a Nu Plasma MC-ICP-MS in dry plasma mode, applying a combination of standard-sample bracketing and external normalization by Cu doping. Argon interferences were determined prior to each analysis and automatically subtracted during analysis. Sample size can be varied between 200 and 600 ng of Fe per measurement and total procedural blanks are better than 10 ng of Fe. Typical external precision of replicate analyses (1S.D.) is +/-0.07 per thousand on delta(56)Fe and +/-0.09 per thousand on delta(57)Fe while typical internal precision of a measurement (1S.E.) is +/-0.03 per thousand on delta(56)Fe and +/-0.04 per thousand on delta(57)Fe. Accuracy and precision were assured by the analysis of reference material IRMM-014, an in-house pure Fe standard, an in-house rock standard, as well as by inter-laboratory comparison using a hematite standard from ETH (Zürich). The lowest amount of Fe (200 ng) at which a reliable isotopic measurement could still be performed corresponds to a DFe or PFe concentration of approximately 2 nmol L(-1) for a 2 L sample size. To show the versatility of the method, results are presented from contrasting environments characterized by a wide range of Fe concentrations as well as varying salt content: the Scheldt estuary, the North Sea, and Antarctic pack ice. The range of DFe and PFe concentrations encountered in this investigation falls between 2 and 2000 nmol L(-1) Fe. The distinct isotopic compositions detected in these environments cover the whole range reported in previous studies of natural Fe isotopic fractionation in the marine environment, i.e. delta(56)Fe varies between -3.5 per thousand and +1.5 per thousand. The largest fractionations were observed in environments characterized by redox changes and/or strong Fe cycling. This demonstrates the potential use of Fe isotopes as a tool to trace marine biogeochemical processes involving Fe.

Prefrontal Neural Activity When Feedback Is Not Relevant to Adjust Performance

PubMed Central

Özyurt, Jale; Rietze, Mareike; Thiel, Christiane M.

2012-01-01

It has been shown that the rostral cingulate zone (RCZ) in humans uses both positive and negative feedback to evaluate performance and to flexibly adjust behaviour. Less is known on how the feedback types are processed by the RCZ and other prefrontal brain areas, when feedback can only be used to evaluate performance, but cannot be used to adjust behaviour. The present fMRI study aimed at investigating feedback that can only be used to evaluate performance in a word-learning paradigm. One group of volunteers (N = 17) received informative, performance-dependent positive or negative feedback after each trial. Since new words had to be learnt in each trial, the feedback could not be used for task-specific adaptations. The other group (N = 17) always received non-informative feedback, providing neither information about performance nor about possible task-specific adaptations. Effects of the informational value of feedback were assessed between-subjects, comparing trials with positive and negative informative feedback to non-informative feedback. Effects of feedback valence were assessed by comparing neural activity to positive and negative feedback within the informative-feedback group. Our results show that several prefrontal regions, including the pre-SMA, the inferior frontal cortex and the insula were sensitive to both, the informational value and the valence aspect of the feedback with stronger activations to informative as compared to non-informative feedback and to informative negative compared to informative positive feedback. The only exception was RCZ which was sensitive to the informational value of the feedback, but not to feedback valence. The findings indicate that outcome information per se is sufficient to activate prefrontal brain regions, with the RCZ being the only prefrontal brain region which is equally sensitive to positive and negative feedback. PMID:22615774

Numerical fatigue 3D-FE modeling of indirect composite-restored posterior teeth.

PubMed

Ausiello, Pietro; Franciosa, Pasquale; Martorelli, Massimo; Watts, David C

2011-05-01

In restored teeth, stresses at the tooth-restoration interface during masticatory processes may fracture the teeth or the restoration and cracks may grow and propagate. The aim was to apply numerical methodologies to simulate the behavior of a restored tooth and to evaluate fatigue lifetimes before crack failure. Using a CAD-FEM procedure and fatigue mechanic laws, the fatigue damage of a restored molar was numerically estimated. Tessellated surfaces of enamel and dentin were extracted by applying segmentation and classification algorithms, to sets of 2D image data. A user-friendly GUI, which enables selection and visualization of 3D tessellated surfaces, was developed in a MatLab(®) environment. The tooth-boundary surfaces of enamel and dentin were then created by sweeping operations through cross-sections. A class II MOD cavity preparation was then added into the 3D model and tetrahedral mesh elements were generated. Fatigue simulation was performed by combining a preliminary static FEA simulation with classical fatigue mechanical laws. Regions with the shortest fatigue-life were located around the fillets of the class II MOD cavity, where the static stress was highest. The described method can be successfully adopted to generate detailed 3D-FE models of molar teeth, with different cavities and restorative materials. This method could be quickly implemented for other dental or biomechanical applications. Copyright © 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Assessing the Roles of Iron, Macronutrients and Wet deposition in Controlling Phytoplankton Growth in Seasonally Oligotrophic Waters of the Mid-Atlantic Bight

NASA Astrophysics Data System (ADS)

Sedwick, P.; Mulholland, M. R.; Najjar, R.; Bernhardt, P. W.; Price, L. M.; Sohst, B. M.; Sookhdeo, C.; Widner, B.

2016-02-01

The role of iron supply in regulating phytoplankton production in high-nutrient, low-chlorophyll ocean regions has been well established. Less clear, however, is the importance of iron for phytoplankton processes in other oceanic settings, such as coastal and oligotrophic waters, where differential changes in the supply and removal of dissolved iron (dFe) can result in limitation or co-limitation of growth due to iron deficiency. One such region of interest is the Mid-Atlantic Bight (MAB), where previous field experiments have provided some evidence of co-limitation of algal growth by nitrogen and iron. In summer 2014 we conducted field sampling and shipboard experiments to assess the role of iron and macronutrient availability in controlling primary production in seasonally oligotrophic waters over the MAB continental slope, with a focus on the the impacts of wet deposition. Our results indicate that nitrogen was the proximate limiting nutrient, with a secondary limitation imposed by availability of phosphorus; we found no evidence for a deficiency in dFe, which was present at concentrations in the range 0.3-0.9 nM. Phytoplankton growth was clearly stimulated by the addition of natural rainwater, suggesting that summer rain events stimulate primary production in the MAB by contributing new nitrogen (primarily as ammonium) and phosphorus, whilst maintaining iron-replete conditions.

EMG Versus Torque Control of Human-Machine Systems: Equalizing Control Signal Variability Does not Equalize Error or Uncertainty.

PubMed

Johnson, Reva E; Kording, Konrad P; Hargrove, Levi J; Sensinger, Jonathon W

2017-06-01

In this paper we asked the question: if we artificially raise the variability of torque control signals to match that of EMG, do subjects make similar errors and have similar uncertainty about their movements? We answered this question using two experiments in which subjects used three different control signals: torque, torque+noise, and EMG. First, we measured error on a simple target-hitting task in which subjects received visual feedback only at the end of their movements. We found that even when the signal-to-noise ratio was equal across EMG and torque+noise control signals, EMG resulted in larger errors. Second, we quantified uncertainty by measuring the just-noticeable difference of a visual perturbation. We found that for equal errors, EMG resulted in higher movement uncertainty than both torque and torque+noise. The differences suggest that performance and confidence are influenced by more than just the noisiness of the control signal, and suggest that other factors, such as the user's ability to incorporate feedback and develop accurate internal models, also have significant impacts on the performance and confidence of a person's actions. We theorize that users have difficulty distinguishing between random and systematic errors for EMG control, and future work should examine in more detail the types of errors made with EMG control.

A parametric LQ approach to multiobjective control system design

NASA Technical Reports Server (NTRS)

Kyr, Douglas E.; Buchner, Marc

1988-01-01

The synthesis of a constant parameter output feedback control law of constrained structure is set in a multiple objective linear quadratic regulator (MOLQR) framework. The use of intuitive objective functions such as model-following ability and closed-loop trajectory sensitivity, allow multiple objective decision making techniques, such as the surrogate worth tradeoff method, to be applied. For the continuous-time deterministic problem with an infinite time horizon, dynamic compensators as well as static output feedback controllers can be synthesized using a descent Anderson-Moore algorithm modified to impose linear equality constraints on the feedback gains by moving in feasible directions. Results of three different examples are presented, including a unique reformulation of the sensitivity reduction problem.

Feedback stabilization of resistive wall modes in a reversed-field pinch

NASA Astrophysics Data System (ADS)

Brunsell, P. R.; Yadikin, D.; Gregoratto, D.; Paccagnella, R.; Liu, Y. Q.; Cecconello, M.; Drake, J. R.; Manduchi, G.; Marchiori, G.

2005-09-01

An array of saddle coils having Nc=16 equally spaced positions along the toroidal direction has been installed for feedback control of resistive wall modes (RWMs) on the EXTRAP T2R reversed-field pinch [P. R. Brunsell, H. Bergsaker, M. Cecconello et al., Plasma Phys. Controlled Fusion 43, 1457 (2001)]. Using feedback, multiple nonresonant RWMs are simultaneously suppressed for three to four wall times. Feedback stabilization of RWMs results in a significant prolongation of the discharge duration. This is linked to a better sustainment of the plasma and tearing mode toroidal rotation with feedback. Due to the limited number of coils in the toroidal direction, pairs of modes with toroidal mode numbers n ,n' that fulfill the condition ∣n-n'∣=Nc are coupled by the feedback action from the discrete coil array. With only one unstable mode in a pair of coupled modes, the suppression of the unstable mode is successful. If two modes are unstable in a coupled pair, two possibilities exist: partial suppression of both modes or, alternatively, complete stabilization of one target mode while the other is left unstable.

Significance of auditory and kinesthetic feedback to singers' pitch control.

PubMed

Mürbe, Dirk; Pabst, Friedemann; Hofmann, Gert; Sundberg, Johan

2002-03-01

An accurate control of fundamental frequency (F0) is required from singers. This control relies on auditory and kinesthetic feedback. However, a loud accompaniment may mask the auditory feedback, leaving the singers to rely on kinesthetic feedback. The object of the present study was to estimate the significance of auditory and kinesthetic feedback to pitch control in 28 students beginning a professional solo singing education. The singers sang an ascending and descending triad pattern covering their entire pitch range with and without masking noise in legato and staccato and in a slow and a fast tempo. F0 was measured by means of a computer program. The interval sizes between adjacent tones were determined and their departures from equally tempered tuning were calculated. The deviations from this tuning were used as a measure of the accuracy of intonation. Statistical analysis showed a significant effect of masking that amounted to a mean impairment of pitch accuracy by 14 cent across all subjects. Furthermore, significant effects were found of tempo as well as of the staccato/legato conditions. The results indicate that auditory feedback contributes significantly to singers' control of pitch.

Study of aerodynamic technology for single-cruise-engine VSTOL fighter/attack aircraft, phase 1

NASA Technical Reports Server (NTRS)

Foley, W. H.; Sheridan, A. E.; Smith, C. W.

1982-01-01

A conceptual design and analysis on a single engine VSTOL fighter/attack aircraft is completed. The aircraft combines a NASA/deHavilland ejector with vectored thrust and is capable of accomplishing the mission and point performance of type Specification 169, and a flight demonstrator could be built with an existing F101/DFE engine. The aerodynamic, aero/propulsive, and propulsive uncertainties are identified, and a wind tunnel program is proposed to address those uncertainties associated with wing borne flight.

Better Communication Research Programme: Language and Literacy Attainment of Pupils during Early Years and through KS2: Does Teacher Assessment at Five Provide a Valid Measure of Children's Current and Future Educational Attainments? Research Brief. DFE-RB172a

ERIC Educational Resources Information Center

Snowling, Margaret J.; Hulme, Charles; Bailey, Alison M.; Stothard, Susan E.; Lindsay, Geoff

2011-01-01

It is well-established that language skills are amongst the best predictors of educational success. Consistent with this, findings from a population-based longitudinal study of parents and children in the UK indicate that language development at the age of two years predicts children's performance on entering primary school. Moreover, children who…

The Canadian Diving Symposium (2nd) Held at Defence and Civil Institute of Environmental Medicine, 31 October - 1 November 1977.

DTIC Science & Technology

1977-11-01

in oceanography, marine sL veying and marine engineering. The elective subjects cover such topics as hydrographic sur- veying, sounding , underwater...and Diving in Mr. J. Tomlinson D.F.E. Department of Fisheries and Marine Services L.Portable System for Ultrasonic Mr. B. EAtock, DCIEM Doppler...semi-tropical and temperate environments (1). As with all homeothermic mammals , the human body has a deep internal temperattre of approximately 37 0

[Significance of auditory and kinesthetic feedback in vocal training of young professional singers (students)].

PubMed

Ciochină, Al D; Ciochină, Paula; Cobzeanu, M D; Burlui, Ada; Zaharia, D

2004-01-01

The study was to estimate the significance of auditory and kinesthetic feedback to an accurate control of fundamental frequency (F0) in 18 students beginning a professional singing education. The students sing an ascending and descending triad pattern covering their entire pitch range with and without making noise in legato and staccato and in a slow and fast tempo. F0 was measured by a computer program. The interval sizes between adjacent tones were determined and their departures from equally tempered tuning were calculated, the deviation from this tuning were used as a measure of the accuracy of intonation. Intonation accuracy was reduced by masking noise, by staccato as opposed to legato singing, and by fast as opposed to slow performance. The contribution of the auditory feedback to pitch control was not significantly improved after education, whereas the kinesthetic feedback circuit was improved in slow legato and slow staccato tasks. The results support the assumption that the kinesthetic feedback contributes substantially to intonation accuracy.

Video Feedback in Key Word Signing Training for Preservice Direct Support Staff.

PubMed

Rombouts, Ellen; Meuris, Kristien; Maes, Bea; De Meyer, Anne-Marie; Zink, Inge

2016-04-01

Research has demonstrated that formal training is essential for professionals to learn key word signing. Yet, the particular didactic strategies have not been studied. Therefore, this study compared the effectiveness of verbal and video feedback in a key word signing training for future direct support staff. Forty-nine future direct support staff were randomly assigned to 1 of 3 key word signing training programs: modeling and verbal feedback (classical method [CM]), additional video feedback (+ViF), and additional video feedback and photo reminder (+ViF/R). Signing accuracy and training acceptability were measured 1 week after and 7 months after training. Participants from the +ViF/R program achieved significantly higher signing accuracy compared with the CM group. Acceptability ratings did not differ between any of the groups. Results suggest that at an equal time investment, the programs containing more training components were more effective. Research on the effect of rehearsal on signing maintenance is warranted.

Feedback increases benefits but not costs of retrieval practice: Retrieval-induced forgetting is strength independent.

PubMed

Tempel, Tobias; Frings, Christian

2018-04-01

We examined how the provision of feedback affected two separate effects of retrieval practice: strengthening of practiced information and forgetting of related, unpracticed information. Feedback substantially increased recall of retrieval-practiced items. This unsurprising result shows once again that restudy opportunities boost the benefits of testing. In contrast, retrieval-induced forgetting was unaffected by the manipulation and occurred in equal size with or without feedback. These findings demonstrate strength independence of retrieval-induced forgetting and thus support a theoretical account assuming that an inhibitory mechanism causes retrieval-induced forgetting. According to this theory, inhibition resolves competition that arises during retrieval attempts but is unrelated to the consequences of retrieval practice concerning practiced items. The present results match these assumptions and contradict the theoretical alternative that blocking by strengthened information might explain retrieval-induced forgetting. We discuss our findings against the background of previous studies.

Learning versus correct models: influence of model type on the learning of a free-weight squat lift.

PubMed

McCullagh, P; Meyer, K N

1997-03-01

It has been assumed that demonstrating the correct movement is the best way to impart task-relevant information. However, empirical verification with simple laboratory skills has shown that using a learning model (showing an individual in the process of acquiring the skill to be learned) may accelerate skill acquisition and increase retention more than using a correct model. The purpose of the present study was to compare the effectiveness of viewing correct versus learning models on the acquisition of a sport skill (free-weight squat lift). Forty female participants were assigned to four learning conditions: physical practice receiving feedback, learning model with model feedback, correct model with model feedback, and learning model without model feedback. Results indicated that viewing either a correct or learning model was equally effective in learning correct form in the squat lift.

Log amplifier with pole-zero compensation

DOEpatents

Brookshier, W.

1985-02-08

A logarithmic amplifier circuit provides pole-zero compensation for improved stability and response time over 6-8 decades of input signal frequency. The amplifer circuit includes a first operational amplifier with a first feedback loop which includes a second, inverting operational amplifier in a second feedstock loop. The compensated output signal is provided by the second operational amplifier with the log elements, i.e., resistors, and the compensating capacitors in each of the feedback loops having equal values so that each break point is offset by a compensating break point or zero.

Opto-electronic oscillators having optical resonators

NASA Technical Reports Server (NTRS)

Yao, Xiaotian Steve (Inventor); Maleki, Lutfollah (Inventor); Ilchenko, Vladimir (Inventor)

2003-01-01

Systems and techniques of incorporating an optical resonator in an optical part of a feedback loop in opto-electronic oscillators. This optical resonator provides a sufficiently long energy storage time and hence to produce an oscillation of a narrow linewidth and low phase noise. Certain mode matching conditions are required. For example, the mode spacing of the optical resonator is equal to one mode spacing, or a multiplicity of the mode spacing, of an opto-electronic feedback loop that receives a modulated optical signal and to produce an electrical oscillating signal.

Temporal prediction modulates the evaluative processing of "good" action feedback: An electrophysiological study.

PubMed

Kimura, Kenta; Kimura, Motohiro; Iwaki, Sunao

2016-10-01

The present study aimed to investigate whether or not the evaluative processing of action feedback can be modulated by temporal prediction. For this purpose, we examined the effects of the predictability of the timing of action feedback on an ERP effect that indexed the evaluative processing of action feedback, that is, an ERP effect that has been interpreted as a feedback-related negativity (FRN) elicited by "bad" action feedback or a reward positivity (RewP) elicited by "good" action feedback. In two types of experimental blocks, the participants performed a gambling task in which they chose one of two cards and received an action feedback that indicated monetary gain or loss. In fixed blocks, the time interval between the participant's choice and the onset of the action feedback was fixed at 0, 500, or 1,000 ms in separate blocks; thus, the timing of action feedback was predictable. In mixed blocks, the time interval was randomly chosen from the same three intervals with equal probability; thus, the timing was less predictable. The results showed that the FRN/RewP was smaller in mixed than fixed blocks for the 0-ms interval trial, whereas there was no difference between the two block types for the 500-ms and 1,000-ms interval trials. Interestingly, the smaller FRN/RewP was due to the modulation of gain ERPs rather than loss ERPs. These results suggest that temporal prediction can modulate the evaluative processing of action feedback, and particularly good feedback, such as that which indicates monetary gain. © 2016 Society for Psychophysiological Research.

Toxicity potentials from waste cellular phones, and a waste management policy integrating consumer, corporate, and government responsibilities

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

Lim, Seong-Rin; Schoenung, Julie M., E-mail: jmschoenung@ucdavis.ed

Cellular phones have high environmental impact potentials because of their heavy metal content and current consumer attitudes toward purchasing new phones with higher functionality and neglecting to return waste phones into proper take-back systems. This study evaluates human health and ecological toxicity potentials from waste cellular phones; highlights consumer, corporate, and government responsibilities for effective waste management; and identifies key elements needed for an effective waste management strategy. The toxicity potentials are evaluated by using heavy metal content, respective characterization factors, and a pathway and impact model for heavy metals that considers end-of-life disposal in landfills or by incineration. Cancermore » potentials derive primarily from Pb and As; non-cancer potentials primarily from Cu and Pb; and ecotoxicity potentials primarily from Cu and Hg. These results are not completely in agreement with previous work in which leachability thresholds were the metric used to establish priority, thereby indicating the need for multiple or revised metrics. The triple bottom line of consumer, corporate, and government responsibilities is emphasized in terms of consumer attitudes, design for environment (DfE), and establishment and implementation of waste management systems including recycling streams, respectively. The key strategic elements for effective waste management include environmental taxation and a deposit-refund system to motivate consumer responsibility, which is linked and integrated with corporate and government responsibilities. The results of this study can contribute to DfE and waste management policy for cellular phones.« less

Tannic acid modulates NFκB signaling pathway and skin inflammation in NC/Nga mice through PPARγ expression.

PubMed

Karuppagounder, Vengadeshprabhu; Arumugam, Somasundaram; Thandavarayan, Rajarajan Amirthalingam; Pitchaimani, Vigneshwaran; Sreedhar, Remya; Afrin, Rejina; Harima, Meilei; Suzuki, Hiroshi; Nomoto, Mayumi; Miyashita, Shizuka; Suzuki, Kenji; Nakamura, Masahiko; Ueno, Kazuyuki; Watanabe, Kenichi

2015-12-01

Polyphenolic compound tannic acid, which is mainly found in grapes and green tea, is a potent antioxidant with anticarcinogenic activities. In this present study, we hypothesized that tannic acid could inhibit nuclear factor (NF)κB signaling and inflammation in atopic dermatitis (AD) NC/Nga mice. We have analyzed the effects of tannic acid on dermatitis severity, histopathology and expression of inflammatory signaling proteins in house dust mite extract induced AD mouse skin. In addition, serum levels of T helper (Th) cytokines (interferon (IFN)γ, interleukin (IL)-4) were measured by enzyme-linked immunosorbent assay. Treatment with tannic acid ameliorated the development of AD-like clinical symptoms and effectively inhibited hyperkeratosis, parakeratosis, acanthosis, mast cells and infiltration of inflammatory cells in the AD mouse skin. Serum levels of IFNγ and IL-4 were significantly down-regulated by tannic acid. Furthermore, tannic acid treatment inhibited DfE induced tumor necrosis factor (TNF)α, high mobility group protein (HMG)B1, receptor for advanced glycation end products (RAGE), extracellular signal-regulated kinase (ERK)1/2, NFκB, cyclooxygenase (COX)2, IL-1β and increased the protein expression of peroxisome proliferator-activated receptor (PPAR)γ. Taken together, our results demonstrate that, DfE induced skin inflammation might be mediated through NFκB signaling and tannic acid may be a potential therapeutic agent for AD, which may possibly act via induction of PPARγ protein. Copyright © 2015 Elsevier Ltd. All rights reserved.

Toxicity potentials from waste cellular phones, and a waste management policy integrating consumer, corporate, and government responsibilities.

PubMed

Lim, Seong-Rin; Schoenung, Julie M

2010-01-01

Cellular phones have high environmental impact potentials because of their heavy metal content and current consumer attitudes toward purchasing new phones with higher functionality and neglecting to return waste phones into proper take-back systems. This study evaluates human health and ecological toxicity potentials from waste cellular phones; highlights consumer, corporate, and government responsibilities for effective waste management; and identifies key elements needed for an effective waste management strategy. The toxicity potentials are evaluated by using heavy metal content, respective characterization factors, and a pathway and impact model for heavy metals that considers end-of-life disposal in landfills or by incineration. Cancer potentials derive primarily from Pb and As; non-cancer potentials primarily from Cu and Pb; and ecotoxicity potentials primarily from Cu and Hg. These results are not completely in agreement with previous work in which leachability thresholds were the metric used to establish priority, thereby indicating the need for multiple or revised metrics. The triple bottom line of consumer, corporate, and government responsibilities is emphasized in terms of consumer attitudes, design for environment (DfE), and establishment and implementation of waste management systems including recycling streams, respectively. The key strategic elements for effective waste management include environmental taxation and a deposit-refund system to motivate consumer responsibility, which is linked and integrated with corporate and government responsibilities. The results of this study can contribute to DfE and waste management policy for cellular phones. 2010 Elsevier Ltd. All rights reserved.

An anti-barotrauma system for preventing barotrauma during hyperbaric oxygen therapy.

PubMed

Song, Moon; Hoon, Se Jeon; Shin, Tae Min

2018-01-01

In the present study, a tympanometry-based anti-barotrauma (ABT) device was designed using eardrum admittance measurements to develop an objective method of preventing barotrauma that occurs during hyperbaric oxygen (HBO₂) therapy. The middle ear space requires active equalization, and barotrauma of these tissues during HBO₂therapy constitutes the most common treatment-associated injury. Decongestant nasal sprays and nasal steroids are used, but their efficacy is questionable to prevent middle ear barotrauma (MEB) during HBO₂ treatment. Accordingly, a tympanometry-based ABT device was designed using eardrum admittance measurements to develop an objective method for preventing MEB, which causes pain and injury, and represents one of the principal reasons for patients to stop treatment. This study was conducted to test a novel technology that can be used to measure transmembrane pressures, and provide chamber attendants with real-time feedback regarding the patient's equalization status prior to the onset of pain or injury. Eardrum admittance values were measured according to pressure changes inside a hyperbaric oxygen chamber while the system was fitted to the subject. When the pressure increased to above 200 daPa, eardrum admittance decreased to 16.255% of prepressurization levels. After pressure equalization was achieved, eardrum admittance recovered to 95.595% of prepressurization levels. A one-way repeated measures analysis of variance contrast test was performed on eardrum admittance before pressurization versus during pressurization, and before pressurization versus after pressure equalization. The analysis revealed significant differences at all points during pressurization (P⟨0.001), but no significant difference after pressure equalization was achieved. This ABT device can provide objective feedback reflecting eardrum condition to the patient and the chamber operator during HBO₂ therapy. Copyright© Undersea and Hyperbaric Medical Society.

Coulomb stress transfer and tectonic loading preceding the 2002 Denali fault earthquake

USGS Publications Warehouse

Bufe, Charles G.

2006-01-01

Pre-2002 tectonic loading and Coulomb stress transfer are modeled along the rupture zone of the M 7.9 Denali fault earthquake (DFE) and on adjacent segments of the right-lateral Denali–Totschunda fault system in central Alaska, using a three-dimensional boundary-element program. The segments modeled closely follow, for about 95°, the arc of a circle of radius 375 km centered on an inferred asperity near the northeastern end of the intersection of the Patton Bay fault with the Alaskan megathrust under Prince William Sound. The loading model includes slip of 6 mm/yr below 12 km along the fault system, consistent with rotation of the Wrangell block about the asperity at a rate of about 1°/m.y. as well as slip of the Pacific plate at 5 cm/yr at depth along the Fairweather–Queen Charlotte transform fault system and on the Alaska megathrust. The model is consistent with most available pre-2002 Global Positioning System (GPS) displacement rate data. Coulomb stresses induced on the Denali–Totschunda fault system (locked above 12 km) by slip at depth and by transfer from the M 9.2 Prince William Sound earthquake of 1964 dominated the changing Coulomb stress distribution along the fault. The combination of loading (∼70–85%) and coseismic stress transfer from the great 1964 earthquake (∼15–30%) were the principal post-1900 stress factors building toward strike-slip failure of the northern Denali and Totschunda segments in the M 7.9 earthquake of November 2002. Postseismic stresses transferred from the 1964 earthquake may also have been a significant factor. The M 7.2–7.4 Delta River earthquake of 1912 (Carver et al., 2004) may have delayed or advanced the timing of the DFE, depending on the details and location of its rupture. The initial subevent of the 2002 DFE earthquake was on the 40-km Susitna Glacier thrust fault at the western end of the Denali fault rupture. The Coulomb stress transferred from the 1964 earthquake moved the Susitna Glacier thrust fault uniformly away from thrust failure by about 100 kPa. The initiation of the Denali fault earthquake was advanced by transfer of 30–50 kPa of positive Coulomb stress to the Susitna Glacier fault (Anderson and Ji, 2003) by the nearby M 6.7 Nenana Mountain foreshock of 23 October 2002. The regional tectonic loading model used here suggests that the Semidi (Alaska Peninsula) segment of the megathrust that ruptured in 1938 (M 8.2) may be reloaded and approaching failure.

Robust stabilization of the Space Station in the presence of inertia matrix uncertainty

NASA Technical Reports Server (NTRS)

Wie, Bong; Liu, Qiang; Sunkel, John

1993-01-01

This paper presents a robust H-infinity full-state feedback control synthesis method for uncertain systems with D11 not equal to 0. The method is applied to the robust stabilization problem of the Space Station in the face of inertia matrix uncertainty. The control design objective is to find a robust controller that yields the largest stable hypercube in uncertain parameter space, while satisfying the nominal performance requirements. The significance of employing an uncertain plant model with D11 not equal 0 is demonstrated.

TRADOC Union List of Periodicals.

DTIC Science & Technology

1988-08-01

Comp11t er Products TSO Nov 1987+ Compul er Rev iew TRQ 1980. Computer Security Journal TRADOC UNION LIST OF SERIALS P\\GE 103 TSO 1987+ Computer Shopper...c:urrcnrt monith onl.N TSP 1988+ TS( cu-rrenft year only TTF Ap1)r 21 , ŝ 86 + TT1T[’ rr-erit ,ear only De fvii <t - v ’P,’ort T s : 12+ Dfe r :iS 5...Executive Orders TTG 1948-1962. Executive Proclamations TTG 1955-1960. Executive Productivity TSR 0277-5298 current year only Executive Risk Assessment TRC V

High Resolution Spectroscopy of 1,2-Difluoroethane in a Molecular Beam: A Case Study of Vibrational Mode-Coupling

DTIC Science & Technology

1992-05-29

Spectroscopy of 1,2- Difluoroethane in a Molecular Beam: A Case Study of Vibrational Mode-Coupling by Steven W. Mork, C. Cameron Miller, and Laura A...and sale; its distribution is unlimited. 92-14657 l9lll l l l , II a HIGH RESOLUTION SPECTROSCOPY OF 1,2- DIFLUOROETHANE IN A MOLECULAR BEAM: A CASE...14853-1301 Abstract The high resolution infrared spectrum of 1,2- difluoroethane (DFE) in a molecular beam has been obtained over the 2978-2996 cm-1

Effectiveness of patient feedback as an educational intervention to improve medical student consultation (PTA Feedback Study): study protocol for a randomized controlled trial.

PubMed

Lai, Michelle Mei Yee; Roberts, Noel; Martin, Jenepher

2014-09-17

Oral feedback from clinical educators is the traditional teaching method for improving clinical consultation skills in medical students. New approaches are needed to enhance this teaching model. Multisource feedback is a commonly used assessment method for learning among practising clinicians, but this assessment has not been explored rigorously in medical student education. This study seeks to evaluate if additional feedback on patient satisfaction improves medical student performance. The Patient Teaching Associate (PTA) Feedback Study is a single site randomized controlled, double-blinded trial with two parallel groups.An after-hours general practitioner clinic in Victoria, Australia, is adapted as a teaching clinic during the day. Medical students from two universities in their first clinical year participate in six simulated clinical consultations with ambulatory patient volunteers living with chronic illness. Eligible students will be randomized in equal proportions to receive patient satisfaction score feedback with the usual multisource feedback and the usual multisource feedback alone as control. Block randomization will be performed. We will assess patient satisfaction and consultation performance outcomes at baseline and after one semester and will compare any change in mean scores at the last session from that at baseline. We will model data using regression analysis to determine any differences between intervention and control groups. Full ethical approval has been obtained for the study. This trial will comply with CONSORT guidelines and we will disseminate data at conferences and in peer-reviewed journals. This is the first proposed trial to determine whether consumer feedback enhances the use of multisource feedback in medical student education, and to assess the value of multisource feedback in teaching and learning about the management of ambulatory patients living with chronic conditions. Australian New Zealand Clinical Trials Registry (ANZCTR): ACTRN12613001055796.

Factors influencing responsiveness to feedback: on the interplay between fear, confidence, and reasoning processes.

PubMed

Eva, Kevin W; Armson, Heather; Holmboe, Eric; Lockyer, Jocelyn; Loney, Elaine; Mann, Karen; Sargeant, Joan

2012-03-01

Self-appraisal has repeatedly been shown to be inadequate as a mechanism for performance improvement. This has placed greater emphasis on understanding the processes through which self-perception and external feedback interact to influence professional development. As feedback is inevitably interpreted through the lens of one's self-perceptions it is important to understand how learners interpret, accept, and use feedback (or not) and the factors that influence those interpretations. 134 participants from 8 health professional training/continuing competence programs were recruited to participate in focus groups. Analyses were designed to (a) elicit understandings of the processes used by learners and physicians to interpret, accept and use (or not) data to inform their perceptions of their clinical performance, and (b) further understand the factors (internal and external) believed to influence interpretation of feedback. Multiple influences appear to impact upon the interpretation and uptake of feedback. These include confidence, experience, and fear of not appearing knowledgeable. Importantly, however, each could have a paradoxical effect of both increasing and decreasing receptivity. Less prevalent but nonetheless important themes suggested mechanisms through which cognitive reasoning processes might impede growth from formative feedback. Many studies have examined the effectiveness of feedback through variable interventions focused on feedback delivery. This study suggests that it is equally important to consider feedback from the perspective of how it is received. The interplay observed between fear, confidence, and reasoning processes reinforces the notion that there is no simple recipe for the delivery of effective feedback. These factors should be taken into account when trying to understand (a) why self-appraisal can be flawed, (b) why appropriate external feedback is vital (yet can be ineffective), and (c) why we may need to disentangle the goals of performance improvement from the goals of improving self-assessment.

Calculation of Weapon Platform Attitude and Cant using Available Sensor Feedback

DTIC Science & Technology

2018-02-01

terrain presents challenges for firing large caliber weapons. When a weapon is fired, the forward momentum of the discharge is equally reflected to the...GIDEP Operations Center P.O. Box 8000 Corona , CA 91718-8000 gidep@gidep.org UNCLASSIFIED Approved for public release; distribution

24 CFR 203.255 - Insurance of mortgage.

Code of Federal Regulations, 2011 CFR

2011-04-01

... prescribed by the Secretary, stating that the underwriter has personally reviewed the appraisal report and..., reports and loan samples that enable FHA to evaluate program operation; (3) Not use TOTAL to direct... algorithm in TOTAL; (5) Not provide feedback messages that conflict with the Equal Credit Opportunity Act...

DC attenuation meter

DOEpatents

Hargrove, Douglas L.

2004-09-14

A portable, hand-held meter used to measure direct current (DC) attenuation in low impedance electrical signal cables and signal attenuators. A DC voltage is applied to the signal input of the cable and feedback to the control circuit through the signal cable and attenuators. The control circuit adjusts the applied voltage to the cable until the feedback voltage equals the reference voltage. The "units" of applied voltage required at the cable input is the system attenuation value of the cable and attenuators, which makes this meter unique. The meter may be used to calibrate data signal cables, attenuators, and cable-attenuator assemblies.

Time-domain digital pre-equalization for band-limited signals based on receiver-side adaptive equalizers.

PubMed

Zhang, Junwen; Yu, Jianjun; Chi, Nan; Chien, Hung-Chang

2014-08-25

We theoretically and experimentally investigate a time-domain digital pre-equalization (DPEQ) scheme for bandwidth-limited optical coherent communication systems, which is based on feedback of channel characteristics from the receiver-side blind and adaptive equalizers, such as least-mean-squares (LMS) algorithm and constant or multi- modulus algorithms (CMA, MMA). Based on the proposed DPEQ scheme, we theoretically and experimentally study its performance in terms of various channel conditions as well as resolutions for channel estimation, such as filtering bandwidth, taps length, and OSNR. Using a high speed 64-GSa/s DAC in cooperation with the proposed DPEQ technique, we successfully synthesized band-limited 40-Gbaud signals in modulation formats of polarization-diversion multiplexed (PDM) quadrature phase shift keying (QPSK), 8-quadrature amplitude modulation (QAM) and 16-QAM, and significant improvement in both back-to-back and transmission BER performances are also demonstrated.

Phase inverter provides variable reference push-pull output

NASA Technical Reports Server (NTRS)

1966-01-01

Dual-transistor difference amplifier provides a push-pull output referenced to a dc potential which can be varied without affecting the signal levels. The amplifier is coupled with a feedback circuit which can vary the operating points of the transistors by equal amounts to provide the variable reference potentials.

Negative Reinforcement Impairs Overnight Memory Consolidation

ERIC Educational Resources Information Center

Stamm, Andrew W.; Nguyen, Nam D.; Seicol, Benjamin J.; Fagan, Abigail; Oh, Angela; Drumm, Michael; Lundt, Maureen; Stickgold, Robert; Wamsley, Erin J.

2014-01-01

Post-learning sleep is beneficial for human memory. However, it may be that not all memories benefit equally from sleep. Here, we manipulated a spatial learning task using monetary reward and performance feedback, asking whether enhancing the salience of the task would augment overnight memory consolidation and alter its incorporation into…

The impact of immediate or delayed feedback on driving behaviour in a simulated Pay-As-You-Drive system.

PubMed

Dijksterhuis, Chris; Lewis-Evans, Ben; Jelijs, Bart; de Waard, Dick; Brookhuis, Karel; Tucha, Oliver

2015-02-01

Pay-As-You-Drive (PAYD) insurance links an individual's driving behaviour to the insurance fee that they pay, making car insurance more actuarially accurate. The best known PAYD insurance format is purely mileage based and is estimated to reduce accidents by about 15% (Litman, 2011). However, these benefits could be further enhanced by incorporating a wider range of driving behaviours, such as lateral and longitudinal accelerations and speeding behaviour, thereby stimulating not only a safe but also an eco-friendly driving style. Currently, feedback on rewards and driver behaviour is mostly provided through a web-based interface, which is presented temporally separated from driving. However, providing immediate feedback within the vehicle itself could elicit more effect. To investigate this hypothesis, two groups of 20 participants drove with a behavioural based PAYD system in a driving simulator and were provided with either delayed feedback through a website, or immediate feedback through an in-car interface, allowing them to earn up to €6 extra. To be clear, every participant in the web group did actually view their feedback during the one week between sessions. Results indicate clear driving behaviour improvements for both PAYD groups as compared to baseline rides and an equal sized control group. After both PAYD groups had received feedback, the initial advantage of the in-car group was reduced substantially. Taken together with usability ratings and driving behaviours in specific situations these results show a moderate advantage of using immediate in-car feedback. However, the study also showed that under conditions of feedback certainty, the effectiveness of delayed feedback approaches that of immediate feedback as compared to a naïve control group. Copyright © 2014 Elsevier Ltd. All rights reserved.

Asymmetries in Climate Change Feedbacks: Why the Future may be Hotter Than you Think

NASA Astrophysics Data System (ADS)

Torn, M. S.; Harte, J.

2006-12-01

Feedbacks in the climate system are major sources of uncertainty, and climate predictions do not yet include one key set of feedbacks, namely biospheric greenhouse gas (GhG) feedbacks. Historical evidence shows that atmospheric GhG concentrations increase during periods of warming, implying a positive feedback to future climate change. We quantify this feedback for carbon dioxide (CO2) and methane (CH4) by combining the mathematics of feedback with both empirical ice-core information and general circulation model climate sensitivity. We find that a warming of 1.7-5.8°C predicted for the year 2100 is amplified to a warming commitment of 1.9-7.7°C, with the range deriving from different GCM simulations and paleo temperature records. Thus, anthropogenic emissions result in higher final GhG concentrations, and therefore more warming, than would be predicted in the absence of this feedback. Uncertainty in climate change predictions have been used as a rationale for inaction against the threat of global warming, based on a prevailing view that the uncertainties are symmetric, giving equal support to climate "optimists" (who think it will be a small problem) and "pessimists," (it will be a big problem). Our results show that even a symmetrical uncertainty in any component of feedback, whether positive or negative, produces an asymmetrical distribution of expected temperatures skewed towards higher temperature. For both reasons, the omission of key positive feedbacks and asymmetrical uncertainty from feedbacks, it is likely that the future will be hotter than we think, which implies more severe climate change impacts. Thus, these results suggest that a conservative policy approach would employ lower emission targets and tighter stabilization time horizons than would otherwise be required.

Suppressive effect of an aqueous extract of Diospyros kaki calyx on dust mite extract/2,4-dinitrochlorobenzene-induced atopic dermatitis-like skin lesions.

PubMed

Yu, Ju-Hee; Jin, Meiling; Choi, Young-Ae; Jeong, Na-Hee; Park, Jeong-Sook; Shin, Tae-Yong; Kim, Sang-Hyun

2017-08-01

Atopic dermatitis (AD) is a common chronic inflammatory skin disease, affecting 10-20% of individuals worldwide. Therefore, the discovery of drugs for treating AD is an attractive subject and important to human health. Diospyros kaki and Diospyros kaki (D. kaki) folium exert beneficial effects on allergic inflammation. However, the effect of D. kaki calyx on AD remains elusive. The present study evaluated the effects of an aqueous extract of D. kaki calyx (AEDKC) on AD-like skin lesions using mouse and keratinocyte models. We used a mouse AD model by the repeated skin exposure of house dust mite extract [Dermatophagoides farinae extract (DFE)] and 2,4-dinitrochlorobenzene (DNCB) to the ears. In addition, to determine the underlying mechanism of its operation, tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ)-activated keratinocytes (HaCaT) were used. Oral administration of AEDKC decreased AD-like skin lesions, as demonstrated by the reduced ear thickness, serum immunoglobulin E (IgE), DFE-specific IgE, IgG2a, histamine level and inflammatory cell infiltration. AEDKC inhibited the expression of pro-inflammatory cytokines and a chemokine via downregulation of nuclear factor-κB and signal transducer and activator of transcription 1 in HaCaT cells. On examination of the AD-related factors in vivo and in vitro, it was confirmed that AEDKC decreased AD-like skin lesions. Taken together, the results suggest that AEDKC is a potential drug candidate for the treatment of AD.

Esculetin from Fraxinus rhynchophylla attenuates atopic skin inflammation by inhibiting the expression of inflammatory cytokines.

PubMed

Jeong, Na-Hee; Yang, Eun-Ju; Jin, Meiling; Lee, Jong Yeong; Choi, Young-Ae; Park, Pil-Hoon; Lee, Sang-Rae; Kim, Sun-Uk; Shin, Tae-Yong; Kwon, Taeg Kyu; Jang, Yong Hyun; Song, Kyung-Sik; Kim, Sang-Hyun

2018-06-01

Atopic dermatitis (AD) is a common chronic inflammatory skin disorder afflicting from infancy to adults with itching, scratching, and lichenification. We aimed to investigate the effects of esculetin from Fraxinus rhynchophylla on atopic skin inflammation. For induction of atopic skin inflammation, we exposed the ears of female BALB/c mice to house dust mite (Dermatophagoides farinae extract, DFE) and 2,4-dinitrochlorobenzene (DNCB) for 4 weeks. Oral administration of esculetin reduced the symptoms of DFE/DNCB-induced atopic skin inflammation, which were evaluated based on ear swelling and number of scratch bouts. The immunoglobulin (Ig) E, IgG2a, and histamine levels in serum were decreased and inflammatory cell infiltration in skin tissue was reduced by the esculetin. It suppressed production of Th1, Th2 and Th17-related cytokines such as tumor necrosis factor (TNF)-α, interferon (IFN)-γ, interleukin (IL)-4, IL-13, IL-31 and IL-17 in the ear tissue. Furthermore, we investigated the effects of esculetin on activated keratinocytes, which are representative cells used for studying the pathogenesis of acute and chronic atopic skin inflammation. As results, esculetin suppressed gene expression of Th1, Th2 and Th17 cytokines and the activation of nuclear factor-κB and signal transducer and activator of transcription 1 in TNF-α/IFN-γ-stimulated keratinocytes. Taken together, these results imply that esculetin attenuated atopic skin inflammation, suggesting that esculetin could be a potential therapeutic candidate for the treatment of AD. Copyright © 2018 Elsevier B.V. All rights reserved.

Negative Feedback Enables Fast and Flexible Collective Decision-Making in Ants

PubMed Central

Grüter, Christoph; Schürch, Roger; Czaczkes, Tomer J.; Taylor, Keeley; Durance, Thomas; Jones, Sam M.; Ratnieks, Francis L. W.

2012-01-01

Positive feedback plays a major role in the emergence of many collective animal behaviours. In many ants pheromone trails recruit and direct nestmate foragers to food sources. The strong positive feedback caused by trail pheromones allows fast collective responses but can compromise flexibility. Previous laboratory experiments have shown that when the environment changes, colonies are often unable to reallocate their foragers to a more rewarding food source. Here we show both experimentally, using colonies of Lasius niger, and with an agent-based simulation model, that negative feedback caused by crowding at feeding sites allows ant colonies to maintain foraging flexibility even with strong recruitment to food sources. In a constant environment, negative feedback prevents the frequently found bias towards one feeder (symmetry breaking) and leads to equal distribution of foragers. In a changing environment, negative feedback allows a colony to quickly reallocate the majority of its foragers to a superior food patch that becomes available when foraging at an inferior patch is already well underway. The model confirms these experimental findings and shows that the ability of colonies to switch to a superior food source does not require the decay of trail pheromones. Our results help to resolve inconsistencies between collective foraging patterns seen in laboratory studies and observations in the wild, and show that the simultaneous action of negative and positive feedback is important for efficient foraging in mass-recruiting insect colonies. PMID:22984518

What supervisors say in their feedback: construction of CanMEDS roles in workplace settings.

PubMed

Renting, Nienke; Dornan, Tim; Gans, Rijk O B; Borleffs, Jan C C; Cohen-Schotanus, Janke; Jaarsma, A Debbie C

2016-05-01

The CanMEDS framework has been widely adopted in residency education and feedback processes are guided by it. It is, however, only one of many influences on what is actually discussed in feedback. The sociohistorical culture of medicine and individual supervisors' contexts, experiences and beliefs are also influential. Our aim was to find how CanMEDS roles are constructed in feedback in a postgraduate curriculum-in-action. We applied a set of discourse analytic tools to written feedback from 591 feedback forms from 7 hospitals, including 3150 feedback comments in which 126 supervisors provided feedback to 120 residents after observing their performance in authentic settings. The role of Collaborator was constructed in two different ways: a cooperative discourse of equality with other workers and patients; and a discourse, which gave residents positions of power-delegating, asserting and 'taking a firm stance'. Efficiency-being fast and to the point emerged as an important attribute of physicians. Patients were seldom part of the discourses and, when they were, they were constructed as objects of communication and collaboration rather than partners. Although some of the discourses are in line with what might be expected, others were in striking contrast to the spirit of CanMEDS. This study's findings suggest that it takes more than a competency framework, evaluation instruments, and supervisor training to change the culture of workplaces. The impact on residents of training in such demanding, efficiency-focused clinical environments is an important topic for future research.

Feedback power control strategies in wireless sensor networks with joint channel decoding.

PubMed

Abrardo, Andrea; Ferrari, Gianluigi; Martalò, Marco; Perna, Fabio

2009-01-01

In this paper, we derive feedback power control strategies for block-faded multiple access schemes with correlated sources and joint channel decoding (JCD). In particular, upon the derivation of the feasible signal-to-noise ratio (SNR) region for the considered multiple access schemes, i.e., the multidimensional SNR region where error-free communications are, in principle, possible, two feedback power control strategies are proposed: (i) a classical feedback power control strategy, which aims at equalizing all link SNRs at the access point (AP), and (ii) an innovative optimized feedback power control strategy, which tries to make the network operational point fall in the feasible SNR region at the lowest overall transmit energy consumption. These strategies will be referred to as "balanced SNR" and "unbalanced SNR," respectively. While they require, in principle, an unlimited power control range at the sources, we also propose practical versions with a limited power control range. We preliminary consider a scenario with orthogonal links and ideal feedback. Then, we analyze the robustness of the proposed power control strategies to possible non-idealities, in terms of residual multiple access interference and noisy feedback channels. Finally, we successfully apply the proposed feedback power control strategies to a limiting case of the class of considered multiple access schemes, namely a central estimating officer (CEO) scenario, where the sensors observe noisy versions of a common binary information sequence and the AP's goal is to estimate this sequence by properly fusing the soft-output information output by the JCD algorithm.

Self-Controlled Feedback Facilitates Motor Learning in Both High and Low Activity Individuals

PubMed Central

Fairbrother, Jeffrey T.; Laughlin, David D.; Nguyen, Timothy V.

2012-01-01

The purpose of this study was to determine if high and low activity individuals differed in terms of the effects of self-controlled feedback on the performance and learning of a movement skill. The task consisted of a blindfolded beanbag toss using the non-preferred arm. Participants were pre-screened according to their physical activity level using the International Physical Activity Questionnaire. An equal number of high activity (HA) and low activity (LA) participants were assigned to self-control (SC) and yoked (YK) feedback conditions, creating four groups: Self-Control-High Activity; Self-Control-Low Activity; Yoked-High Activity; and Yoked-Low Activity. SC condition participants were provided feedback whenever they requested it, while YK condition participants received feedback according to a schedule created by their SC counterpart. Results indicated that the SC condition was more accurate than the YK condition during acquisition and transfer phases, and the HA condition was more accurate than the LA condition during all phases of the experiment. A post-training questionnaire indicated that participants in the SC condition asked for feedback mostly after what they perceived to be “good” trials; those in the YK condition indicated that they would have preferred to receive feedback after “good” trials. This study provided further support for the advantages of self-controlled feedback when learning motor skills, additionally showing benefits for both active and less active individuals. The results suggested that the provision of self-controlled feedback to less active learners may be a potential avenue to teaching motor skills necessary to engage in greater amounts of physical activity. PMID:22969745

Attributing Contributions of Climate Feedbacks to the Seasonal Cycle of Surface Warming due to CO2 Increase

NASA Astrophysics Data System (ADS)

Sejas, S.; Cai, M.

2012-12-01

Surfing warming due to CO2 doubling is a robust feature of coupled general circulation models (GCM), as noted in the IPCC AR4 assessment report. In this study, the contributions of different climate feedbacks to the magnitude, spatial distribution, and seasonality of the surface warming is examined using data from NCAR's CCSM4. In particular, a focus is placed on polar regions to see which feedbacks play a role in polar amplification and its seasonal pattern. A new climate feedback analysis method is used to isolate the surface warming or cooling contributions of both radiative and non-radiative (dynamical) climate feedbacks to the total (actual) surface temperature change given by the CCSM4. These contributions (or partial surface temperature changes) are additive and their total is approximately equal to the actual surface temperature change. What is found is that the effects of CO2 doubling alone warms the surface throughout with a maximum in polar regions, which indicates the CO2 forcing alone has a degree of polar warming amplification. Water vapor feedback is a positive feedback throughout but is most responsible for the surface warming found in the tropics. Polar warming amplification is found to be strongest away from summer (especially in NH), which is primarily caused by a positive feedback due to cloud feedbacks but with the surface temperature change due to the CO2 forcing alone and the ocean dynamics and storage feedback also playing an important role. Contrary to popular belief, surface albedo feedback (SAF) does not account for much of the polar amplification. SAF tries to amplify polar warming, but in summer. No major polar amplification is seen in summer for the actual surface temperature, so SAF is not the feedback responsible for polar amplification. This is actually a consequence of the ocean dynamics and storage feedback, which negates the effects of SAF to a large degree.

Changes in ENSO amplitude under climate warming and cooling

NASA Astrophysics Data System (ADS)

Wang, Yingying; Luo, Yiyong; Lu, Jian; Liu, Fukai

2018-05-01

The response of ENSO amplitude to climate warming and cooling is investigated using the Community Earth System Model (CESM), in which the warming and cooling scenarios are designed by adding heat fluxes of equal amplitude but opposite sign onto the ocean surface, respectively. Results show that the warming induces an increase of the ENSO amplitude but the cooling gives rise to a decrease of the ENSO amplitude, and these changes are robust in statistics. A mixed layer heat budget analysis finds that the increasing (decreasing) SST tendency under climate warming (cooling) is mainly due to an enhancement (weakening) of dynamical feedback processes over the equatorial Pacific, including zonal advective (ZA) feedback, meridional advective (MA) feedback, thermocline (TH) feedback, and Ekman (EK) feedback. As the climate warms, a wind anomaly of the same magnitude across the equatorial Pacific can induce a stronger zonal current change in the east (i.e., a stronger ZA feedback), which in turn produces a greater weakening of upwelling (i.e., a stronger EK feedback) and thus a larger thermocline change (i.e., a stronger TH feedback). In response to the climate warming, in addition, the MA feedback is also strengthened due to an enhancement of the meridional SST gradient around the equator resulting from a weakening of the subtropical cells (STCs). It should be noted that the weakened STCs itself has a negative contribution to the change of the MA feedback which, however, appears to be secondary. And vice versa for the cooling case. Bjerknes linear stability (BJ) index is also evaluated for the linear stability of ENSO, with remarkably larger (smaller) BJ index found for the warming (cooling) case.

Integrated Control Using the SOFFT Control Structure

NASA Technical Reports Server (NTRS)

Halyo, Nesim

1996-01-01

The need for integrated/constrained control systems has become clearer as advanced aircraft introduced new coupled subsystems such as new propulsion subsystems with thrust vectoring and new aerodynamic designs. In this study, we develop an integrated control design methodology which accomodates constraints among subsystem variables while using the Stochastic Optimal Feedforward/Feedback Control Technique (SOFFT) thus maintaining all the advantages of the SOFFT approach. The Integrated SOFFT Control methodology uses a centralized feedforward control and a constrained feedback control law. The control thus takes advantage of the known coupling among the subsystems while maintaining the identity of subsystems for validation purposes and the simplicity of the feedback law to understand the system response in complicated nonlinear scenarios. The Variable-Gain Output Feedback Control methodology (including constant gain output feedback) is extended to accommodate equality constraints. A gain computation algorithm is developed. The designer can set the cross-gains between two variables or subsystems to zero or another value and optimize the remaining gains subject to the constraint. An integrated control law is designed for a modified F-15 SMTD aircraft model with coupled airframe and propulsion subsystems using the Integrated SOFFT Control methodology to produce a set of desired flying qualities.

Resistive instabilities in tokamaks

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

Rutherford, P.H.

1985-10-01

Low-m tearing modes constitute the dominant instability problem in present-day tokamaks. In this lecture, the stability criteria for representative current profiles with q(0)-values slightly less than unit are reviewed; ''sawtooth'' reconnection to q(0)-values just at, or slightly exceeding, unity is generally destabilizing to the m = 2, n = 1 and m = 3, n = 2 modes, and severely limits the range of stable profile shapes. Feedback stabilization of m greater than or equal to 2 modes by rf heating or current drive, applied locally at the magnetic islands, appears feasible; feedback by island current drive is much moremore » efficient, in terms of the radio-frequency power required, then feedback by island heating. Feedback stabilization of the m = 1 mode - although yielding particularly beneficial effects for resistive-tearing and high-beta stability by allowing q(0)-values substantially below unity - is more problematical, unless the m = 1 ideal-MHD mode can be made positively stable by strong triangular shaping of the central flux surfaces. Feedback techniques require a detectable, rotating MHD-like signal; the slowing of mode rotation - or the excitation of non-rotating modes - by an imperfectly conducting wall is also discussed.« less

40 CFR 86.1333-90 - Transient test cycle generation.

Code of Federal Regulations, 2012 CFR

2012-07-01

... zero percent speed specified in the engine dynamometer schedules (appendix I (f)(1), (f)(2), or (f)(3... feedback torque equal to zero (using, for example, clutch disengagement, speed to torque control switching... reference speed and reference torque are zero percent values. For each idle segment that is ten seconds or...

40 CFR 86.1333-90 - Transient test cycle generation.

Code of Federal Regulations, 2013 CFR

2013-07-01

... zero percent speed specified in the engine dynamometer schedules (appendix I (f)(1), (f)(2), or (f)(3... feedback torque equal to zero (using, for example, clutch disengagement, speed to torque control switching... reference speed and reference torque are zero percent values. For each idle segment that is ten seconds or...

40 CFR 86.1333-90 - Transient test cycle generation.

Code of Federal Regulations, 2011 CFR

2011-07-01

... zero percent speed specified in the engine dynamometer schedules (appendix I (f)(1), (f)(2), or (f)(3... feedback torque equal to zero (using, for example, clutch disengagement, speed to torque control switching... reference speed and reference torque are zero percent values. For each idle segment that is ten seconds or...

An Autonomous Sensor System Architecture for Active Flow and Noise Control Feedback

NASA Technical Reports Server (NTRS)

Humphreys, William M, Jr.; Culliton, William G.

2008-01-01

Multi-channel sensor fusion represents a powerful technique to simply and efficiently extract information from complex phenomena. While the technique has traditionally been used for military target tracking and situational awareness, a study has been successfully completed that demonstrates that sensor fusion can be applied equally well to aerodynamic applications. A prototype autonomous hardware processor was successfully designed and used to detect in real-time the two-dimensional flow reattachment location generated by a simple separated-flow wind tunnel model. The success of this demonstration illustrates the feasibility of using autonomous sensor processing architectures to enhance flow control feedback signal generation.

Highly efficient single-pass frequency doubling of a continuous-wave distributed feedback laser diode using a PPLN waveguide crystal at 488 nm.

PubMed

Jechow, Andreas; Schedel, Marco; Stry, Sandra; Sacher, Joachim; Menzel, Ralf

2007-10-15

A continuous-wave distributed feedback diode laser emitting at 976 nm was frequency doubled by the use of a periodically poled lithium niobate waveguide crystal with a channel size of 3 microm x 5 microm and an interaction length of 10 mm. A laser to waveguide coupling efficiency of 75% could be achieved resulting in 304 mW of incident infrared light inside the waveguide. Blue laser light emission of 159 mW at 488 nm has been generated, which equals to a conversion efficiency of 52%. The resulting wall plug efficiency was 7.4%.

The analysis of HIV/AIDS drug-resistant on networks

NASA Astrophysics Data System (ADS)

Liu, Maoxing

2014-01-01

In this paper, we present an Human Immunodeficiency Virus (HIV)/Acquired Immune Deficiency Syndrome (AIDS) drug-resistant model using an ordinary differential equation (ODE) model on scale-free networks. We derive the threshold for the epidemic to be zero in infinite scale-free network. We also prove the stability of disease-free equilibrium (DFE) and persistence of HIV/AIDS infection. The effects of two immunization schemes, including proportional scheme and targeted vaccination, are studied and compared. We find that targeted strategy compare favorably to a proportional condom using has prominent effect to control HIV/AIDS spread on scale-free networks.

Feeding and Feedback in the Powerful Radio Galaxy 3C 120

NASA Technical Reports Server (NTRS)

Tombesi, F.; Mushotzky, R. F.; Reynolds, C. S.; Kallman, T.; Reeves, J. N.; Braito, V.; Ueda, Y.; Leutenegger, M. A.; Williams, B. J.; Stawarz, L.;

A Digital Map From External Forcing to the Final Surface Warming Pattern and its Seasonal Cycle

NASA Astrophysics Data System (ADS)

Cai, M.

2015-12-01

Historically, only the thermodynamic processes (e.g., water vapor, cloud, surface albedo, and atmospheric lapse rate) that directly influence the top of the atmosphere (TOA) radiative energy flux balance are considered in climate feedback analysis. One of my recent research areas is to develop a new framework for climate feedback analysis that explicitly takes into consideration not only the thermodynamic processes that the directly influence the TOA radiative energy flux balance but also the local dynamical (e.g., evaporation, surface sensible heat flux, vertical convections etc) and non-local dynamical (large-scale horizontal energy transport) processes in aiming to explain the warming asymmetry between high and low latitudes, between ocean and land, and between the surface and atmosphere. In the last 5-6 years, we have developed a coupled atmosphere-surface climate feedback-response analysis method (CFRAM) as a new framework for estimating climate feedback and sensitivity in coupled general circulation models with a full physical parameterization package. In the CFRAM, the isolation of partial temperature changes due to an external forcing alone or an individual feedback is achieved by solving the linearized infrared radiation transfer model subject to individual energy flux perturbations (external or due to feedbacks). The partial temperature changes are addable and their sum is equal to the (total) temperature change (in the linear sense). The CFRAM is used to isolate the partial temperature changes due to the external forcing, due to water vapor feedback, clouds, surface albedo, local vertical convection, and non-local atmospheric dynamical feedbacks, as well as oceanic heat storage. It has been shown that seasonal variations in the cloud feedback, surface albedo feedback, and ocean heat storage/dynamics feedback, directly caused by the strong annual cycle of insolation, contribute primarily to the large seasonal variation of polar warming. Furthermore, the CO2 forcing, and water vapor and atmospheric dynamics feedbacks add to the maximum polar warming in fall/winter.

Equality bias impairs collective decision-making across cultures

PubMed Central

Mahmoodi, Ali; Bang, Dan; Olsen, Karsten; Zhao, Yuanyuan Aimee; Shi, Zhenhao; Broberg, Kristina; Safavi, Shervin; Han, Shihui; Nili Ahmadabadi, Majid; Frith, Chris D.; Roepstorff, Andreas; Rees, Geraint; Bahrami, Bahador

2015-01-01

We tend to think that everyone deserves an equal say in a debate. This seemingly innocuous assumption can be damaging when we make decisions together as part of a group. To make optimal decisions, group members should weight their differing opinions according to how competent they are relative to one another; whenever they differ in competence, an equal weighting is suboptimal. Here, we asked how people deal with individual differences in competence in the context of a collective perceptual decision-making task. We developed a metric for estimating how participants weight their partner’s opinion relative to their own and compared this weighting to an optimal benchmark. Replicated across three countries (Denmark, Iran, and China), we show that participants assigned nearly equal weights to each other’s opinions regardless of true differences in their competence—even when informed by explicit feedback about their competence gap or under monetary incentives to maximize collective accuracy. This equality bias, whereby people behave as if they are as good or as bad as their partner, is particularly costly for a group when a competence gap separates its members. PMID:25775532

Equality bias impairs collective decision-making across cultures.

PubMed

Mahmoodi, Ali; Bang, Dan; Olsen, Karsten; Zhao, Yuanyuan Aimee; Shi, Zhenhao; Broberg, Kristina; Safavi, Shervin; Han, Shihui; Nili Ahmadabadi, Majid; Frith, Chris D; Roepstorff, Andreas; Rees, Geraint; Bahrami, Bahador

2015-03-24

We tend to think that everyone deserves an equal say in a debate. This seemingly innocuous assumption can be damaging when we make decisions together as part of a group. To make optimal decisions, group members should weight their differing opinions according to how competent they are relative to one another; whenever they differ in competence, an equal weighting is suboptimal. Here, we asked how people deal with individual differences in competence in the context of a collective perceptual decision-making task. We developed a metric for estimating how participants weight their partner's opinion relative to their own and compared this weighting to an optimal benchmark. Replicated across three countries (Denmark, Iran, and China), we show that participants assigned nearly equal weights to each other's opinions regardless of true differences in their competence-even when informed by explicit feedback about their competence gap or under monetary incentives to maximize collective accuracy. This equality bias, whereby people behave as if they are as good or as bad as their partner, is particularly costly for a group when a competence gap separates its members.

Real-time feedback enhances forward propulsion during walking in old adults.

PubMed

Franz, Jason R; Maletis, Michela; Kram, Rodger

2014-01-01

Reduced propulsive function during the push-off phase of walking plays a central role in the deterioration of walking ability with age. We used real-time propulsive feedback to test the hypothesis that old adults have an underutilized propulsive reserve available during walking. 8 old adults (mean [SD], age: 72.1 [3.9] years) and 11 young adults (age: 21.0 [1.5] years) participated. For our primary aim, old subjects walked: 1) normally, 2) with visual feedback of their peak propulsive ground reaction forces, and 3) with visual feedback of their medial gastrocnemius electromyographic activity during push-off. We asked those subjects to match a target set to 20% and 40% greater propulsive force or push-off muscle activity than normal walking. We tested young subjects walking normally only to provide reference ground reaction force values. Walking normally, old adults exerted 12.5% smaller peak propulsive forces than young adults (P<0.01). However, old adults significantly increased their propulsive forces and push-off muscle activities when we provided propulsive feedback. Most notably, force feedback elicited propulsive forces that were equal to or 10.5% greater than those of young adults (+20% target, P=0.87; +40% target, P=0.02). With electromyographic feedback, old adults significantly increased their push-off muscle activities but without increasing their propulsive forces. Old adults with propulsive deficits have a considerable and underutilized propulsive reserve available during level walking. Further, real-time propulsive feedback represents a promising therapeutic strategy to improve the forward propulsion of old adults and thus maintain their walking ability and independence. © 2013.

Adult Age Differences in Learning from Positive and Negative Probabilistic Feedback

PubMed Central

Simon, Jessica R.; Howard, James H.; Howard, Darlene V.

2010-01-01

Objective Past research has investigated age differences in frontal-based decision making, but few studies have focused on the behavioral effects of striatal-based changes in healthy aging. Feedback learning has been found to vary with dopamine levels; increases in dopamine facilitate learning from positive feedback, whereas decreases facilitate learning from negative feedback. Given previous evidence of striatal dopamine depletion in healthy aging, we investigated behavioral differences between college-aged and healthy old adults using a feedback learning task that is sensitive to both frontal and striatal processes. Method Seventeen college-aged (M = 18.9 years) and 24 healthy, older adults (M = 70.3 years) completed the Probabilistic selection task, in which participants are trained on probabilistic stimulus-outcome information and then tested to determine whether they learned more from positive or negative feedback. Results As a group, the old adults learned equally well from positive and negative feedback, whereas the college-aged group learned more from positive than negative feedback, F(1, 39) = 4.10, p < .05, reffect = .3. However, these group differences were not due to the older individuals being more balanced learners. Most individuals of both ages were balanced learners, but while all of the remaining young learners had a positive bias, the remaining older learners were split between those with positive and negative learning biases (χ2(2) = 6.12, p<.047). Conclusions These behavioral results are consistent with the dopamine theory of striatal aging, and suggest there might be adult age differences in the kinds of information people use when faced with a current choice. PMID:20604627

Feedback Power Control Strategies in Wireless Sensor Networks with Joint Channel Decoding

PubMed Central

Abrardo, Andrea; Ferrari, Gianluigi; Martalò, Marco; Perna, Fabio

2009-01-01

In this paper, we derive feedback power control strategies for block-faded multiple access schemes with correlated sources and joint channel decoding (JCD). In particular, upon the derivation of the feasible signal-to-noise ratio (SNR) region for the considered multiple access schemes, i.e., the multidimensional SNR region where error-free communications are, in principle, possible, two feedback power control strategies are proposed: (i) a classical feedback power control strategy, which aims at equalizing all link SNRs at the access point (AP), and (ii) an innovative optimized feedback power control strategy, which tries to make the network operational point fall in the feasible SNR region at the lowest overall transmit energy consumption. These strategies will be referred to as “balanced SNR” and “unbalanced SNR,” respectively. While they require, in principle, an unlimited power control range at the sources, we also propose practical versions with a limited power control range. We preliminary consider a scenario with orthogonal links and ideal feedback. Then, we analyze the robustness of the proposed power control strategies to possible non-idealities, in terms of residual multiple access interference and noisy feedback channels. Finally, we successfully apply the proposed feedback power control strategies to a limiting case of the class of considered multiple access schemes, namely a central estimating officer (CEO) scenario, where the sensors observe noisy versions of a common binary information sequence and the AP's goal is to estimate this sequence by properly fusing the soft-output information output by the JCD algorithm. PMID:22291536

Effectiveness and cost of different strategies for information feedback in general practice.

PubMed Central

Szczepura, A; Wilmot, J; Davies, C; Fletcher, J

1994-01-01

AIM. The aim of this study was to determine the effectiveness and relative cost of three forms of information feedback to general practices--graphical, graphical plus a visit by a medical facilitator and tabular. METHOD. Routinely collected, centrally-held data were used where possible, analysed at practice level. Some non-routine practice data in the form of risk factor recording in medical notes, for example weight, smoking status, alcohol consumption and blood pressure, were also provided to those who requested it. The 52 participating practices were stratified and randomly allocated to one of the three feedback groups. The cost of providing each type of feedback was determined. The immediate response of practitioners to the form of feedback (acceptability), ease of understanding (intelligibility), and usefulness of regular feedback was recorded. Changes introduced as a result of feedback were assessed by questionnaire shortly after feedback, and 12 months later. Changes at the practice level in selected indicators were also assessed 12 and 24 months after initial feedback. RESULTS. The resulting cost per effect was calculated to be 46.10 pounds for both graphical and tabular feedback, 132.50 pounds for graphical feedback plus facilitator visit and 773.00 pounds for the manual audit of risk factors recorded in the practice notes. The three forms of feedback did not differ in intelligibility or usefulness, but feedback plus a medical facilitator visit was significantly less acceptable. There was a high level of self-reported organizational change following feedback, with 69% of practices reporting changes as a direct result; this was not significantly different for the three types of feedback. There were no significant changes in the selected indicators at 12 or 24 months following feedback. The practice characteristic most closely related to better indicators of preventive practice was practice size, smaller practices performing significantly better. Separate clinics were not associated with better preventive practice. CONCLUSION. It is concluded that feedback strategies using graphical and tabular comparative data are equally cost-effective in general practice with about two thirds of practices reporting organizational change as a consequence; feedback involving unsolicited medical facilitator visits is less cost-effective. The cost-effectiveness of manual risk factor audit is also called into question. PMID:8312032

Effect of Training and Level of External Auditory Feedback on the Singing Voice: Pitch Inaccuracy

PubMed Central

Bottalico, Pasquale; Graetzer, Simone; Hunter, Eric J.

2016-01-01

Background One of the aspects of major relevance to singing is the control of fundamental frequency. Objectives The effects on pitch inaccuracy, defined as the distance in cents in equally tempered tuning between the reference note and the sung note, of the following conditions were evaluated: (1) level of external feedback, (2) tempo (slow or fast), (3) articulation (legato or staccato), (4) tessitura (low, medium or high) and (5) semi-phrase direction (ascending or descending). Methods The subjects were 10 non-professional singers, and 10 classically-trained professional or semi-professional singers (10 males and 10 females). Subjects sang one octave and a fifth arpeggi with three different levels of external auditory feedback, two tempi and two articulations (legato or staccato). Results It was observed that inaccuracy was greatest in the descending semi-phrase arpeggi produced at a fast tempo and with a staccato articulation, especially for non-professional singers. The magnitude of inaccuracy was also relatively large in the high tessitura relative to the low and medium tessitura for such singers. Counter to predictions, when external auditory feedback was strongly attenuated by the hearing protectors, non-professional singers showed greater pitch accuracy than in the other external feedback conditions. This finding indicates the importance of internal auditory feedback in pitch control. Conclusions With an increase in training, the singer’s pitch inaccuracy decreases. PMID:26948385

Design for multipurpose use: an application of DfE concept in a developing economy

NASA Astrophysics Data System (ADS)

Dunmade, Israel

2004-12-01

Design for Environment (DfE) has been defined as the systematic integration of environmental considerations into product and process design. And it has been discovered that material and space can be saved when several functions are integrated into a single product by taking advantage of common components. In this design and development project, a multipurpose thresher was designed based on an integrated concept of design for modularity, disassembly, demanufacturing and remanufacturing. The machine can be used to thresh various types of farm produce such as rice, sorghum, cowpea and rye by changing the concave and the cylinder (threshing drum). The configuration of the machine enables access to most of the component parts without changing the tools needed for disassembly because the same type of fasteners was used. Furthermore, the functional units (the shelling unit, the separation unit and the grading unit) were assembled into modules such that only the faulty part needs to be replaced if necessary. The design was so simplified that the operator can make the changes for different uses without any difficulty. The machine has been successfully tested with a number of these products and it is scheduled for tests with other produce like corn and peanuts. The modularity of the functional unit will facilitate multi-lifecycle use of machine and/or its component parts. The uniformity of the liaisons and simplification of the configuration will reduce both the disassembly times and maintenance cost. By this integration, the material requirements for four different machines are conserved, environmental emissions that would be associated with the manufacture, transportation and disposal of four machines are eliminated while the capital requirements by farmers for machinery are reduced to about a quarter. Consequently the total lifecycle cost is kept minimum while the eco-efficiency is maximized.

Eco-innovation of a wooden childhood furniture set: an example of environmental solutions in the wood sector.

PubMed

González-García, Sara; García Lozano, Raúl; Moreira, M Teresa; Gabarrell, Xavier; Rieradevall i Pons, Joan; Feijoo, Gumersindo; Murphy, Richard J

2012-06-01

The environmental profile of a set of wood furniture was carried out to define the best design criteria for its eco-design. A baby cot convertible into a bed, a study desk and a bedside table were the objects of study. Two quantitative and qualitative environmental approaches were combined in order to propose improvement alternatives: Life Cycle Assessment (LCA) and Design for Environment (DfE). In the first case Life Cycle Assessment (LCA) was applied to identify the hot spots in the product system. As a next step, LCA information was used in eco-briefing to determine several improvement alternatives. A wood products company located in Catalonia (NE Spain) was assessed in detail, dividing the process into three stages: assembly, finishing and packaging. Ten impact categories were considered in the LCA study: abiotic depletion, acidification, eutrophication, global warming, ozone layer depletion, human toxicity, fresh water aquatic ecotoxicity, marine aquatic ecotoxicity, terrestrial ecotoxicity and photochemical oxidant formation. Two processes can be considered the key environmental factors: the production of the wooden boards and electricity, with contributions of 45-68% and 14-33% respectively depending on the impact categories. Subsequently, several improvement alternatives were proposed in the eco-design process (DfE) to achieve reductions in a short-medium period of time in the environmental impact. These eco-design strategies could reduce the environmental profile of the setup by 14%. The correct methodological adaptation of the concept of eco-briefing, as a tool for communication among environmental technicians and designers, the simplification of the analytical tool used and the LCA, could facilitate the environmental analysis of a product. The results obtained provide information that can help the furniture sector to improve their environmental performance. Copyright © 2012 Elsevier B.V. All rights reserved.

Channel Analysis for a 6.4 Gb s-1 DDR5 Data Buffer Receiver Front-End

NASA Astrophysics Data System (ADS)

Lehmann, Stefanie; Gerfers, Friedel

2017-09-01

In this contribution, the channel characteristic of the next generation DDR5-SDRAM architecture and possible approaches to overcome channel impairments are analysed. Because modern enterprise server applications and networks demand higher memory bandwidth, throughput and capacity, the DDR5-SDRAM specification is currently under development as a follow-up of DDR4-SDRAM technology. In this specification, the data rate is doubled to DDR5-6400 per IO as compared to the former DDR4-3200 architecture, resulting in a total per DIMM data rate of up to 409.6 Gb s-1. The single-ended multi-point-to-point CPU channel architecture in DDRX technology remains the same for DDR5 systems. At the specified target data rate, insertion loss, reflections, cross-talk as well as power supply noise become more severe and have to be considered. Using the data buffer receiver front-end of a load-reduced memory module, sophisticated equalisation techniques can be applied to ensure target BER at the increased data rate. In this work, the worst case CPU back-plane channel is analysed to derive requirements for receiver-side equalisation from the channel response characteristics. First, channel impairments such as inter-symbol-interference, reflections from the multi-point channel structure, and crosstalk from neighboring lines are analysed in detail. Based on these results, different correction methods for DDR5 data buffer front-ends are discussed. An architecture with 1-tap FFE in combination with a multi-tap DFE is proposed. Simulation of the architecture using a random input data stream is used to reveal the required DFE tap filter depth to effectively eliminate the dominant ISI and reflection based error components.

An overview of folate status in a population-based study from São Paulo, Brazil and the potential impact of 10 years of national folic acid fortification policy.

PubMed

Steluti, J; Selhub, J; Paul, L; Reginaldo, C; Fisberg, R M; Marchioni, D M L

2017-10-01

Food fortification is an important strategy in public health policy for controlling micronutrient malnutrition and a major contributing factor in the eradication of micronutrients' deficiencies. Approximately 50 countries worldwide have adopted food fortification with folic acid (FA). FA fortification of wheat and maize flours has been mandatory in Brazil since 2004. To assess the effect of 10 years of FA food fortification policy on folate status of residents of São Palo, Brazil using a population-based survey. Data were from 750 individuals aged ⩾12 years who participated in a cross-sectional population-based survey in São Paulo city, Brazil. Fasting blood samples were collected, and folate was assayed by affinity-high performance liquid chromatografy method with electrochemical detection. The participants provided information about food intake based on two 24 h dietary recall. Only 1.76% of population had folate deficiency (<6.8 nmol/l). The mean folate concentration was 29.5 (95% confidence interval: 27.3-31.7) nmol/l for all sex-age groups. The mean folate intake for the population was 375.8 (s.e.m.=6.4) μg/day of dietary folate equivalents (DFEs). When comparing folate intake in DFE from food folate and FA from fortified foods, FA contributed 50% or more of the DFE in almost all sex-age groups. The major contributors of folate intake are processed foods made from wheat flour fortified with FA, especially among subjects younger than 20 years old. The deficiency of folate is very low, and food fortification contributed to folate intake and had a notable influence on rankings of food contributors of folate.

Effects of visual feedback-induced variability on motor learning of handrim wheelchair propulsion.

PubMed

Leving, Marika T; Vegter, Riemer J K; Hartog, Johanneke; Lamoth, Claudine J C; de Groot, Sonja; van der Woude, Lucas H V

2015-01-01

It has been suggested that a higher intra-individual variability benefits the motor learning of wheelchair propulsion. The present study evaluated whether feedback-induced variability on wheelchair propulsion technique variables would also enhance the motor learning process. Learning was operationalized as an improvement in mechanical efficiency and propulsion technique, which are thought to be closely related during the learning process. 17 Participants received visual feedback-based practice (feedback group) and 15 participants received regular practice (natural learning group). Both groups received equal practice dose of 80 min, over 3 weeks, at 0.24 W/kg at a treadmill speed of 1.11 m/s. To compare both groups the pre- and post-test were performed without feedback. The feedback group received real-time visual feedback on seven propulsion variables with instruction to manipulate the presented variable to achieve the highest possible variability (1st 4-min block) and optimize it in the prescribed direction (2nd 4-min block). To increase motor exploration the participants were unaware of the exact variable they received feedback on. Energy consumption and the propulsion technique variables with their respective coefficient of variation were calculated to evaluate the amount of intra-individual variability. The feedback group, which practiced with higher intra-individual variability, improved the propulsion technique between pre- and post-test to the same extent as the natural learning group. Mechanical efficiency improved between pre- and post-test in the natural learning group but remained unchanged in the feedback group. These results suggest that feedback-induced variability inhibited the improvement in mechanical efficiency. Moreover, since both groups improved propulsion technique but only the natural learning group improved mechanical efficiency, it can be concluded that the improvement in mechanical efficiency and propulsion technique do not always appear simultaneously during the motor learning process. Their relationship is most likely modified by other factors such as the amount of the intra-individual variability.

Effects of Visual Feedback-Induced Variability on Motor Learning of Handrim Wheelchair Propulsion

PubMed Central

Leving, Marika T.; Vegter, Riemer J. K.; Hartog, Johanneke; Lamoth, Claudine J. C.; de Groot, Sonja; van der Woude, Lucas H. V.

2015-01-01

Background It has been suggested that a higher intra-individual variability benefits the motor learning of wheelchair propulsion. The present study evaluated whether feedback-induced variability on wheelchair propulsion technique variables would also enhance the motor learning process. Learning was operationalized as an improvement in mechanical efficiency and propulsion technique, which are thought to be closely related during the learning process. Methods 17 Participants received visual feedback-based practice (feedback group) and 15 participants received regular practice (natural learning group). Both groups received equal practice dose of 80 min, over 3 weeks, at 0.24 W/kg at a treadmill speed of 1.11 m/s. To compare both groups the pre- and post-test were performed without feedback. The feedback group received real-time visual feedback on seven propulsion variables with instruction to manipulate the presented variable to achieve the highest possible variability (1st 4-min block) and optimize it in the prescribed direction (2nd 4-min block). To increase motor exploration the participants were unaware of the exact variable they received feedback on. Energy consumption and the propulsion technique variables with their respective coefficient of variation were calculated to evaluate the amount of intra-individual variability. Results The feedback group, which practiced with higher intra-individual variability, improved the propulsion technique between pre- and post-test to the same extent as the natural learning group. Mechanical efficiency improved between pre- and post-test in the natural learning group but remained unchanged in the feedback group. Conclusion These results suggest that feedback-induced variability inhibited the improvement in mechanical efficiency. Moreover, since both groups improved propulsion technique but only the natural learning group improved mechanical efficiency, it can be concluded that the improvement in mechanical efficiency and propulsion technique do not always appear simultaneously during the motor learning process. Their relationship is most likely modified by other factors such as the amount of the intra-individual variability. PMID:25992626

Confinement and diffusion modulate bistability and stochastic switching in a reaction network with positive feedback

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

Mlynarczyk, Paul J.; Pullen, Robert H.; Abel, Steven M., E-mail: abel@utk.edu

2016-01-07

Positive feedback is a common feature in signal transduction networks and can lead to phenomena such as bistability and signal propagation by domain growth. Physical features of the cellular environment, such as spatial confinement and the mobility of proteins, play important but inadequately understood roles in shaping the behavior of signaling networks. Here, we use stochastic, spatially resolved kinetic Monte Carlo simulations to explore a positive feedback network as a function of system size, system shape, and mobility of molecules. We show that these physical properties can markedly alter characteristics of bistability and stochastic switching when compared with well-mixed simulations.more » Notably, systems of equal volume but different shapes can exhibit qualitatively different behaviors under otherwise identical conditions. We show that stochastic switching to a state maintained by positive feedback occurs by cluster formation and growth. Additionally, the frequency at which switching occurs depends nontrivially on the diffusion coefficient, which can promote or suppress switching relative to the well-mixed limit. Taken together, the results provide a framework for understanding how confinement and protein mobility influence emergent features of the positive feedback network by modulating molecular concentrations, diffusion-influenced rate parameters, and spatiotemporal correlations between molecules.« less

A computational feedforward model predicts categorization of masked emotional body language for longer, but not for shorter, latencies.

PubMed

Stienen, Bernard M C; Schindler, Konrad; de Gelder, Beatrice

2012-07-01

Given the presence of massive feedback loops in brain networks, it is difficult to disentangle the contribution of feedforward and feedback processing to the recognition of visual stimuli, in this case, of emotional body expressions. The aim of the work presented in this letter is to shed light on how well feedforward processing explains rapid categorization of this important class of stimuli. By means of parametric masking, it may be possible to control the contribution of feedback activity in human participants. A close comparison is presented between human recognition performance and the performance of a computational neural model that exclusively modeled feedforward processing and was engineered to fulfill the computational requirements of recognition. Results show that the longer the stimulus onset asynchrony (SOA), the closer the performance of the human participants was to the values predicted by the model, with an optimum at an SOA of 100 ms. At short SOA latencies, human performance deteriorated, but the categorization of the emotional expressions was still above baseline. The data suggest that, although theoretically, feedback arising from inferotemporal cortex is likely to be blocked when the SOA is 100 ms, human participants still seem to rely on more local visual feedback processing to equal the model's performance.

Effects of Voice Harmonic Complexity on ERP Responses to Pitch-Shifted Auditory Feedback

PubMed Central

Behroozmand, Roozbeh; Korzyukov, Oleg; Larson, Charles R.

2011-01-01

Objective The present study investigated the neural mechanisms of voice pitch control for different levels of harmonic complexity in the auditory feedback. Methods Event-related potentials (ERPs) were recorded in response to +200 cents pitch perturbations in the auditory feedback of self-produced natural human vocalizations, complex and pure tone stimuli during active vocalization and passive listening conditions. Results During active vocal production, ERP amplitudes were largest in response to pitch shifts in the natural voice, moderately large for non-voice complex stimuli and smallest for the pure tones. However, during passive listening, neural responses were equally large for pitch shifts in voice and non-voice complex stimuli but still larger than that for pure tones. Conclusions These findings suggest that pitch change detection is facilitated for spectrally rich sounds such as natural human voice and non-voice complex stimuli compared with pure tones. Vocalization-induced increase in neural responses for voice feedback suggests that sensory processing of naturally-produced complex sounds such as human voice is enhanced by means of motor-driven mechanisms (e.g. efference copies) during vocal production. Significance This enhancement may enable the audio-vocal system to more effectively detect and correct for vocal errors in the feedback of natural human vocalizations to maintain an intended vocal output for speaking. PMID:21719346

Peer feedback for examiner quality assurance on MRCGP International South Asia: a mixed methods study.

PubMed

Perera, D P; Andrades, Marie; Wass, Val

2017-12-08

The International Membership Examination (MRCGP[INT]) of the Royal College of General Practitioners UK is a unique collaboration between four South Asian countries with diverse cultures, epidemiology, clinical facilities and resources. In this setting good quality assurance is imperative to achieve acceptable standards of inter rater reliability. This study aims to explore the process of peer feedback for examiner quality assurance with regard to factors affecting the implementation and acceptance of the method. A sequential mixed methods approach was used based on focus group discussions with examiners (n = 12) and clinical examination convenors who acted as peer reviewers (n = 4). A questionnaire based on emerging themes and literature review was then completed by 20 examiners at the subsequent OSCE exam. Qualitative data were analysed using an iterative reflexive process. Quantitative data were integrated by interpretive analysis looking for convergence, complementarity or dissonance. The qualitative data helped understand the issues and informed the process of developing the questionnaire. The quantitative data allowed for further refining of issues, wider sampling of examiners and giving voice to different perspectives. Examiners stated specifically that peer feedback gave an opportunity for discussion, standardisation of judgments and improved discriminatory abilities. Interpersonal dynamics, hierarchy and perception of validity of feedback were major factors influencing acceptance of feedback. Examiners desired increased transparency, accountability and the opportunity for equal partnership within the process. The process was stressful for examiners and reviewers; however acceptance increased with increasing exposure to receiving feedback. The process could be refined to improve acceptability through scrupulous attention to training and selection of those giving feedback to improve the perceived validity of feedback and improved reviewer feedback skills to enable better interpersonal dynamics and a more equitable feedback process. It is important to highlight the role of quality assurance and peer feedback as a tool for continuous improvement and maintenance of standards to examiners during training. Examiner quality assurance using peer feedback was generally a successful and accepted process. The findings highlight areas for improvement and guide the path towards a model of feedback that is responsive to examiner views and cultural sensibilities.

The nature of the pressure-induced metallization of FeO and its implications to the core-mantle boundary

USGS Publications Warehouse

Sherman, David M.

1989-01-01

The pressure and temperature-induced metallization of FeO discovered by Knittle et al (1986) is here argued to result from a Mott transition associated with increased Fe(3d)-Fe(3d) orbital overlap at high pressures. Consequently, it is here argued that a lower mantle containing only these phases should be electrically insulating. Finally, the formation of itinerant d-electrons in FeO may be a necessary, if not sufficient, condition for the apparent alloying of FeO with Fe. Such alloying may allow oxygen to be incorporated into the outer core. -from Author

Are All Competencies Equal in the Eyes of Residents? A Multicenter Study of Emergency Medicine Residents' Interest in Feedback.

PubMed

Bentley, Suzanne; Hu, Kevin; Messman, Anne; Moadel, Tiffany; Khandelwal, Sorabh; Streich, Heather; Noelker, Joan

2017-01-01

Feedback, particularly real-time feedback, is critical to resident education. The emergency medicine (EM) milestones were developed in 2012 to enhance resident assessment, and many programs use them to provide focused resident feedback. The purpose of this study was to evaluate EM residents' level of interest in receiving real-time feedback on each of the 23 competencies/sub-competencies. This was a multicenter cross-sectional study of EM residents. We surveyed participants on their level of interest in receiving real-time on-shift feedback on each of the 23 competencies/sub-competencies. Anonymous paper or computerized surveys were distributed to residents at three four-year training programs and three three-year training programs with a total of 223 resident respondents. Residents rated their level of interest in each milestone on a six-point Likert-type response scale. We calculated average level of interest for each of the 23 sub-competencies, for all 223 respondents and separately by postgraduate year (PGY) levels of training. One-way analyses of variance were performed to determine if there were differences in ratings by level of training. The overall survey response rate across all institutions was 82%. Emergency stabilization had the highest mean rating (5.47/6), while technology had the lowest rating (3.24/6). However, we observed no differences between levels of training on any of the 23 competencies/sub-competencies. Residents seem to ascribe much more value in receiving feedback on domains involving high-risk, challenging procedural skills as compared to low-risk technical and communication skills. Further studies are necessary to determine whether residents' perceived importance of competencies/sub-competencies needs to be considered when developing an assessment or feedback program based on these 23 EM competencies/sub-competencies.

Understanding the tropical cloud feedback from an analysis of the circulation and stability regimes simulated from an upgraded multiscale modeling framework

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

Xu, Kuan-Man; Cheng, Anning

As revealed from studies using conventional general circulation models (GCMs), the thermodynamic contribution to the tropical cloud feedback dominates the dynamic contribution, but these models have difficulty in simulating the subsidence regimes in the tropics. In this study, we analyze the tropical cloud feedback from a 2 K sea surface temperature (SST) perturbation experiment performed with a multiscale modeling framework (MMF). The MMF explicitly represents cloud processes using 2-D cloud-resolving models with an advanced higher-order turbulence closure in each atmospheric column of the host GCM. We sort the monthly mean cloud properties and cloud radiative effects according to circulation andmore » stability regimes. Here, we find that the regime-sorted dynamic changes dominate the thermodynamic changes in terms of the absolute magnitude. The dynamic changes in the weak subsidence regimes exhibit strong negative cloud feedback due to increases in shallow cumulus and deep clouds while those in strongly convective and moderate-to-strong subsidence regimes have opposite signs, resulting in a small contribution to cloud feedback. On the other hand, the thermodynamic changes are large due to decreases in stratocumulus clouds in the moderate-to-strong subsidence regimes with small opposite changes in the weak subsidence and strongly convective regimes, resulting in a relatively large contribution to positive cloud feedback. The dynamic and thermodynamic changes contribute equally to positive cloud feedback and are relatively insensitive to stability in the moderate-to-strong subsidence regimes. But they are sensitive to stability changes from the SST increase in convective and weak subsidence regimes. Lastly, these results have implications for interpreting cloud feedback mechanisms.« less

Understanding the tropical cloud feedback from an analysis of the circulation and stability regimes simulated from an upgraded multiscale modeling framework

DOE PAGES

Xu, Kuan-Man; Cheng, Anning

2016-11-15

As revealed from studies using conventional general circulation models (GCMs), the thermodynamic contribution to the tropical cloud feedback dominates the dynamic contribution, but these models have difficulty in simulating the subsidence regimes in the tropics. In this study, we analyze the tropical cloud feedback from a 2 K sea surface temperature (SST) perturbation experiment performed with a multiscale modeling framework (MMF). The MMF explicitly represents cloud processes using 2-D cloud-resolving models with an advanced higher-order turbulence closure in each atmospheric column of the host GCM. We sort the monthly mean cloud properties and cloud radiative effects according to circulation andmore » stability regimes. Here, we find that the regime-sorted dynamic changes dominate the thermodynamic changes in terms of the absolute magnitude. The dynamic changes in the weak subsidence regimes exhibit strong negative cloud feedback due to increases in shallow cumulus and deep clouds while those in strongly convective and moderate-to-strong subsidence regimes have opposite signs, resulting in a small contribution to cloud feedback. On the other hand, the thermodynamic changes are large due to decreases in stratocumulus clouds in the moderate-to-strong subsidence regimes with small opposite changes in the weak subsidence and strongly convective regimes, resulting in a relatively large contribution to positive cloud feedback. The dynamic and thermodynamic changes contribute equally to positive cloud feedback and are relatively insensitive to stability in the moderate-to-strong subsidence regimes. But they are sensitive to stability changes from the SST increase in convective and weak subsidence regimes. Lastly, these results have implications for interpreting cloud feedback mechanisms.« less

Increasing Accountability Measures for Early Childhood Teachers Using Evaluation Models: Observation, Feedback, and Self-Assessment

ERIC Educational Resources Information Center

Reinking, Anna Krummel

2015-01-01

President Barack Obama and U.S. Secretary of Education Arne Duncan are promoting an early learning initiative focusing on the agenda of every four year old having equal access to high-quality early learning environments (Administration for Children and Families, 2013). One way the Federal government is supporting this proposal is through a grant;…

Ocean Variability Effects on Underwater Acoustic Communications

DTIC Science & Technology

2011-09-01

schemes for accessing wide frequency bands. Compared with OFDM schemes, the multiband MIMO transmission combined with time reversal processing...systems, or multiple- input/multiple-output ( MIMO ) systems, decision feedback equalization and interference cancellation schemes have been integrated...unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 2 MIMO receiver also iterates channel estimation and symbol demodulation with

How Toddlers Acquire and Transfer Tool Knowledge: Developmental Changes and the Role of Executive Functions

ERIC Educational Resources Information Center

Pauen, Sabina; Bechtel-Kuehne, Sabrina

2016-01-01

This report investigates tool learning and its relations to executive functions (EFs) in toddlers. In Study 1 (N = 93), 18-, 20-, 22-, and 24-month-old children learned equally well to choose a correct tool from observation, whereas performance based on feedback improved with age. Knowledge transfer showed significant progress after 22 months of…

Do radiative feedbacks depend on the structure and type of climate forcing, or only on the spatial pattern of surface temperature change?

NASA Astrophysics Data System (ADS)

Haugstad, A.; Battisti, D. S.; Armour, K.

2016-12-01

Earth's climate sensitivity depends critically on the strength of radiative feedbacks linking surface warming to changes in top-of-atmosphere (TOA) radiation. Many studies use a simplistic idea of radiative feedbacks, either by treating them as global mean quantities, or by assuming they can be defined uniquely by geographic location and thus that TOA radiative response depends only on local surface warming. For example, a uniform increase in sea-surface temperature has been widely used as a surrogate for global warming (e.g., Cess et al 1990 and the CMIP 'aqua4k' simulations), with the assumption that this produces the same radiative feedbacks as those arising from a doubling of carbon dioxide - even though the spatial patterns of warming differ. However, evidence suggests that these assumptions are not valid, and local feedbacks may be integrally dependent on the structure of warming or type of climate forcing applied (Rose et al 2014). This study thus investigates the following questions: to what extent do local feedbacks depend on the structure and type of forcing applied? And, to what extent do they depend on the pattern of surface temperature change induced by that forcing? Using an idealized framework of an aquaplanet atmosphere-only model, we show that radiative feedbacks are indeed dependent on the large scale structure of warming and type of forcing applied. For example, the climate responds very differently to two forcings of equal global magnitude but applied in different global regions; the pattern of local feedbacks arising from uniform warming are not the same as that arising from polar amplified warming; and the same local feedbacks can be induced by distinct forcing patterns, provided that they produce the same pattern of surface temperature change. These findings suggest that the so-called `efficacies' of climate forcings can be understood simply in terms of how local feedbacks depend on the temperature patterns they induce.

Physical examination skills training: Faculty staff vs. patient instructor feedback-A controlled trial.

PubMed

Krautter, Markus; Diefenbacher, Katja; Schultz, Jobst-Hendrik; Maatouk, Imad; Herrmann-Werner, Anne; Koehl-Hackert, Nadja; Herzog, Wolfgang; Nikendei, Christoph

2017-01-01

Standardized patients are widely used in training of medical students, both in teaching and assessment. They also frequently lead complete training sessions delivering physical examination skills without the aid of faculty teaching staff-acting as "patient instructors" (PIs). An important part of this training is their ability to provide detailed structured feedback to students which has a strong impact on their learning success. Yet, to date no study has assessed the quality of physical examination related feedback by PIs. Therefore, we conducted a randomized controlled study comparing feedback of PIs and faculty staff following a physical examination assessed by students and video assessors. 14 PIs and 14 different faculty staff physicians both delivered feedback to 40 medical students that had performed a physical examination on the respective PI while the physicians observed the performance. The physical examination was rated by two independent video assessors to provide an objective performance standard (gold standard). Feedback of PI and physicians was content analyzed by two different independent video assessors based on a provided checklist and compared to the performance standard. Feedback of PIs and physicians was also rated by medical students and video assessors using a questionnaire consisting of 12 items. There was no statistical significant difference concerning overall matching of physician or PI feedback with gold standard ratings by video assessment (p = .219). There was also no statistical difference when focusing only on items that were classified as major key steps (p = .802), mistakes or parts that were left out during physical examination (p = .219) or mistakes in communication items (p = .517). The feedback of physicians was significantly better rated than PI feedback both by students (p = .043) as well as by video assessors (p = .034). In summary, our study demonstrates that trained PIs are able to provide feedback of equal quantitative value to that of faculty staff physicians with regard to a physical examination performed on them. However, both the students and the video raters judged the quality of the feedback given by the physicians to be significantly better than that of the PIs.

Inverse-model estimates of the ocean's coupled phosphorus, silicon, and iron cycles

NASA Astrophysics Data System (ADS)

Pasquier, Benoît; Holzer, Mark

2017-09-01

The ocean's nutrient cycles are important for the carbon balance of the climate system and for shaping the ocean's distribution of dissolved elements. Dissolved iron (dFe) is a key limiting micronutrient, but iron scavenging is observationally poorly constrained, leading to large uncertainties in the external sources of iron and hence in the state of the marine iron cycle. Here we build a steady-state model of the ocean's coupled phosphorus, silicon, and iron cycles embedded in a data-assimilated steady-state global ocean circulation. The model includes the redissolution of scavenged iron, parameterization of subgrid topography, and small, large, and diatom phytoplankton functional classes. Phytoplankton concentrations are implicitly represented in the parameterization of biological nutrient utilization through an equilibrium logistic model. Our formulation thus has only three coupled nutrient tracers, the three-dimensional distributions of which are found using a Newton solver. The very efficient numerics allow us to use the model in inverse mode to objectively constrain many biogeochemical parameters by minimizing the mismatch between modeled and observed nutrient and phytoplankton concentrations. Iron source and sink parameters cannot jointly be optimized because of local compensation between regeneration, recycling, and scavenging. We therefore consider a family of possible state estimates corresponding to a wide range of external iron source strengths. All state estimates have a similar mismatch with the observed nutrient concentrations and very similar large-scale dFe distributions. However, the relative contributions of aeolian, sedimentary, and hydrothermal iron to the total dFe concentration differ widely depending on the sources. Both the magnitude and pattern of the phosphorus and opal exports are well constrained, with global values of 8. 1 ± 0. 3 Tmol P yr-1 (or, in carbon units, 10. 3 ± 0. 4 Pg C yr-1) and 171. ± 3. Tmol Si yr-1. We diagnose the phosphorus and opal exports supported by aeolian, sedimentary, and hydrothermal iron. The geographic patterns of the export supported by each iron type are well constrained across the family of state estimates. Sedimentary-iron-supported export is important in shelf and large-scale upwelling regions, while hydrothermal iron contributes to export mostly in the Southern Ocean. The fraction of the global export supported by a given iron type varies systematically with its fractional contribution to the total iron source. Aeolian iron is most efficient in supporting export in the sense that its fractional contribution to export exceeds its fractional contribution to the total source. Per source-injected molecule, aeolian iron supports 3. 1 ± 0. 8 times more phosphorus export and 2. 0 ± 0. 5 times more opal export than the other iron types. Conversely, per injected molecule, sedimentary and hydrothermal iron support 2. 3 ± 0. 6 and 4. ± 2. times less phosphorus export, and 1. 9 ± 0. 5 and 2. ± 1. times less opal export than the other iron types.

Active versus Passive Training of a Complex Bimanual Task: Is Prescriptive Proprioceptive Information Sufficient for Inducing Motor Learning?

PubMed Central

Beets, Iseult A. M.; Macé, Marc; Meesen, Raf L. J.; Cuypers, Koen; Levin, Oron; Swinnen, Stephan P.

2012-01-01

Perceptual processes play an important role in motor learning. While it is evident that visual information greatly contributes to learning new movements, much less is known about provision of prescriptive proprioceptive information. Here, we investigated whether passive (proprioceptively-based) movement training was comparable to active training for learning a new bimanual task. Three groups practiced a bimanual coordination pattern with a 1∶2 frequency ratio and a 90° phase offset between both wrists with Lissajous feedback over the course of four days: 1) passive training; 2) active training; 3) no training (control). Retention findings revealed that passive as compared to active training resulted in equally successful acquisition of the frequency ratio but active training was more effective for acquisition of the new relative phasing between the limbs in the presence of augmented visual feedback. However, when this feedback was removed, performance of the new relative phase deteriorated in both groups whereas the frequency ratio was better preserved. The superiority of active over passive training in the presence of augmented feedback is hypothesized to result from active involvement in processes of error detection/correction and planning. PMID:22666379

Associated Effects of Automated Essay Evaluation Software on Growth in Writing Quality for Students with and without Disabilities

ERIC Educational Resources Information Center

Wilson, Joshua

2017-01-01

The present study examined growth in writing quality associated with feedback provided by an automated essay evaluation system called PEG Writing. Equal numbers of students with disabilities (SWD) and typically-developing students (TD) matched on prior writing achievement were sampled (n = 1196 total). Data from a subsample of students (n = 655)…

Anticholinesterase Effects on Number and Function of Brain Muscarinic Receptors and Central Cholinergic Activity: Drug Intervention.

DTIC Science & Technology

1983-09-30

Pathways; GABAergic Pathway; Atropine; Reserpine; Alphamethylparatyrosine; Oxotremorine ; Feedback 20 ABSTRACT (Continue on reverse side It necessary and...see Preface). The purpose was the compare the regional distribution of the effect of anticholinesterases with oxotremorine ),a selective centrally...hippocampus, differently from oxotremorine which was ineffective. In the other two regions, physostigmine and oxotremorine were equally active. At the

Automatic load sharing in inverter modules

NASA Technical Reports Server (NTRS)

Nagano, S.

1979-01-01

Active feedback loads transistor equally with little power loss. Circuit is suitable for balancing modular inverters in spacecraft, computer power supplies, solar-electric power generators, and electric vehicles. Current-balancing circuit senses differences between collector current for power transistor and average value of load currents for all power transistors. Principle is effective not only in fixed duty-cycle inverters but also in converters operating at variable duty cycles.

“Booster” training: Evaluation of instructor-led bedside cardiopulmonary resuscitation skill training and automated corrective feedback to improve cardiopulmonary resuscitation compliance of Pediatric Basic Life Support providers during simulated cardiac arrest

PubMed Central

Sutton, Robert M.; Niles, Dana; Meaney, Peter A.; Aplenc, Richard; French, Benjamin; Abella, Benjamin S.; Lengetti, Evelyn L.; Berg, Robert A.; Helfaer, Mark A.; Nadkarni, Vinay

2013-01-01

Objective To investigate the effectiveness of brief bedside “booster” cardiopulmonary resuscitation (CPR) training to improve CPR guideline compliance of hospital-based pediatric providers. Design Prospective, randomized trial. Setting General pediatric wards at Children’s Hospital of Philadelphia. Subjects Sixty-nine Basic Life Support–certified hospital-based providers. Intervention CPR recording/feedback defibrillators were used to evaluate CPR quality during simulated pediatric arrest. After a 60-sec pretraining CPR evaluation, subjects were randomly assigned to one of three instructional/feedback methods to be used during CPR booster training sessions. All sessions (training/CPR manikin practice) were of equal duration (2 mins) and differed only in the method of corrective feedback given to participants during the session. The study arms were as follows: 1) instructor-only training; 2) automated defibrillator feedback only; and 3) instructor training combined with automated feedback. Measurements and Main Results Before instruction, 57% of the care providers performed compressions within guideline rate recommendations (rate >90 min−1 and <120 min−1); 71% met minimum depth targets (depth, >38 mm); and 36% met overall CPR compliance (rate and depth within targets). After instruction, guideline compliance improved (instructor-only training: rate 52% to 87% [p .01], and overall CPR compliance, 43% to 78% [p < .02]; automated feedback only: rate, 70% to 96% [p = .02], depth, 61% to 100% [p < .01], and overall CPR compliance, 35% to 96% [p < .01]; and instructor training combined with automated feedback: rate 48% to 100% [p < .01], depth, 78% to 100% [p < .02], and overall CPR compliance, 30% to 100% [p < .01]). Conclusions Before booster CPR instruction, most certified Pediatric Basic Life Support providers did not perform guideline-compliant CPR. After a brief bedside training, CPR quality improved irrespective of training content (instructor vs. automated feedback). Future studies should investigate bedside training to improve CPR quality during actual pediatric cardiac arrests. PMID:20625336

"Booster" training: evaluation of instructor-led bedside cardiopulmonary resuscitation skill training and automated corrective feedback to improve cardiopulmonary resuscitation compliance of Pediatric Basic Life Support providers during simulated cardiac arrest.

PubMed

Sutton, Robert M; Niles, Dana; Meaney, Peter A; Aplenc, Richard; French, Benjamin; Abella, Benjamin S; Lengetti, Evelyn L; Berg, Robert A; Helfaer, Mark A; Nadkarni, Vinay

2011-05-01

To investigate the effectiveness of brief bedside "booster" cardiopulmonary resuscitation (CPR) training to improve CPR guideline compliance of hospital-based pediatric providers. Prospective, randomized trial. General pediatric wards at Children's Hospital of Philadelphia. Sixty-nine Basic Life Support-certified hospital-based providers. CPR recording/feedback defibrillators were used to evaluate CPR quality during simulated pediatric arrest. After a 60-sec pretraining CPR evaluation, subjects were randomly assigned to one of three instructional/feedback methods to be used during CPR booster training sessions. All sessions (training/CPR manikin practice) were of equal duration (2 mins) and differed only in the method of corrective feedback given to participants during the session. The study arms were as follows: 1) instructor-only training; 2) automated defibrillator feedback only; and 3) instructor training combined with automated feedback. Before instruction, 57% of the care providers performed compressions within guideline rate recommendations (rate >90 min(-1) and <120 min(-1)); 71% met minimum depth targets (depth, >38 mm); and 36% met overall CPR compliance (rate and depth within targets). After instruction, guideline compliance improved (instructor-only training: rate 52% to 87% [p .01], and overall CPR compliance, 43% to 78% [p < .02]; automated feedback only: rate, 70% to 96% [p = .02], depth, 61% to 100% [p < .01], and overall CPR compliance, 35% to 96% [p < .01]; and instructor training combined with automated feedback: rate 48% to 100% [p < .01], depth, 78% to 100% [p < .02], and overall CPR compliance, 30% to 100% [p < .01]). Before booster CPR instruction, most certified Pediatric Basic Life Support providers did not perform guideline-compliant CPR. After a brief bedside training, CPR quality improved irrespective of training content (instructor vs. automated feedback). Future studies should investigate bedside training to improve CPR quality during actual pediatric cardiac arrests.

Physical examination skills training: Faculty staff vs. patient instructor feedback—A controlled trial

PubMed Central

Diefenbacher, Katja; Schultz, Jobst-Hendrik; Maatouk, Imad; Herrmann-Werner, Anne; Koehl-Hackert, Nadja; Herzog, Wolfgang; Nikendei, Christoph

2017-01-01

Background Standardized patients are widely used in training of medical students, both in teaching and assessment. They also frequently lead complete training sessions delivering physical examination skills without the aid of faculty teaching staff–acting as “patient instructors” (PIs). An important part of this training is their ability to provide detailed structured feedback to students which has a strong impact on their learning success. Yet, to date no study has assessed the quality of physical examination related feedback by PIs. Therefore, we conducted a randomized controlled study comparing feedback of PIs and faculty staff following a physical examination assessed by students and video assessors. Methods 14 PIs and 14 different faculty staff physicians both delivered feedback to 40 medical students that had performed a physical examination on the respective PI while the physicians observed the performance. The physical examination was rated by two independent video assessors to provide an objective performance standard (gold standard). Feedback of PI and physicians was content analyzed by two different independent video assessors based on a provided checklist and compared to the performance standard. Feedback of PIs and physicians was also rated by medical students and video assessors using a questionnaire consisting of 12 items. Results There was no statistical significant difference concerning overall matching of physician or PI feedback with gold standard ratings by video assessment (p = .219). There was also no statistical difference when focusing only on items that were classified as major key steps (p = .802), mistakes or parts that were left out during physical examination (p = .219) or mistakes in communication items (p = .517). The feedback of physicians was significantly better rated than PI feedback both by students (p = .043) as well as by video assessors (p = .034). Conclusions In summary, our study demonstrates that trained PIs are able to provide feedback of equal quantitative value to that of faculty staff physicians with regard to a physical examination performed on them. However, both the students and the video raters judged the quality of the feedback given by the physicians to be significantly better than that of the PIs. PMID:28692703

Effects of voice harmonic complexity on ERP responses to pitch-shifted auditory feedback.

PubMed

Behroozmand, Roozbeh; Korzyukov, Oleg; Larson, Charles R

2011-12-01

The present study investigated the neural mechanisms of voice pitch control for different levels of harmonic complexity in the auditory feedback. Event-related potentials (ERPs) were recorded in response to+200 cents pitch perturbations in the auditory feedback of self-produced natural human vocalizations, complex and pure tone stimuli during active vocalization and passive listening conditions. During active vocal production, ERP amplitudes were largest in response to pitch shifts in the natural voice, moderately large for non-voice complex stimuli and smallest for the pure tones. However, during passive listening, neural responses were equally large for pitch shifts in voice and non-voice complex stimuli but still larger than that for pure tones. These findings suggest that pitch change detection is facilitated for spectrally rich sounds such as natural human voice and non-voice complex stimuli compared with pure tones. Vocalization-induced increase in neural responses for voice feedback suggests that sensory processing of naturally-produced complex sounds such as human voice is enhanced by means of motor-driven mechanisms (e.g. efference copies) during vocal production. This enhancement may enable the audio-vocal system to more effectively detect and correct for vocal errors in the feedback of natural human vocalizations to maintain an intended vocal output for speaking. Copyright © 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Robot-Assisted Proprioceptive Training with Added Vibro-Tactile Feedback Enhances Somatosensory and Motor Performance.

PubMed

Cuppone, Anna Vera; Squeri, Valentina; Semprini, Marianna; Masia, Lorenzo; Konczak, Jürgen

2016-01-01

This study examined the trainability of the proprioceptive sense and explored the relationship between proprioception and motor learning. With vision blocked, human learners had to perform goal-directed wrist movements relying solely on proprioceptive/haptic cues to reach several haptically specified targets. One group received additional somatosensory movement error feedback in form of vibro-tactile cues applied to the skin of the forearm. We used a haptic robotic device for the wrist and implemented a 3-day training regimen that required learners to make spatially precise goal-directed wrist reaching movements without vision. We assessed whether training improved the acuity of the wrist joint position sense. In addition, we checked if sensory learning generalized to the motor domain and improved spatial precision of wrist tracking movements that were not trained. The main findings of the study are: First, proprioceptive acuity of the wrist joint position sense improved after training for the group that received the combined proprioceptive/haptic and vibro-tactile feedback (VTF). Second, training had no impact on the spatial accuracy of the untrained tracking task. However, learners who had received VTF significantly reduced their reliance on haptic guidance feedback when performing the untrained motor task. That is, concurrent VTF was highly salient movement feedback and obviated the need for haptic feedback. Third, VTF can be also provided by the limb not involved in the task. Learners who received VTF to the contralateral limb equally benefitted. In conclusion, somatosensory training can significantly enhance proprioceptive acuity within days when learning is coupled with vibro-tactile sensory cues that provide feedback about movement errors. The observable sensory improvements in proprioception facilitates motor learning and such learning may generalize to the sensorimotor control of the untrained motor tasks. The implications of these findings for neurorehabilitation are discussed.

Midterm peer feedback in problem-based learning groups: the effect on individual contributions and achievement.

PubMed

Kamp, Rachelle J A; van Berkel, Henk J M; Popeijus, Herman E; Leppink, Jimmie; Schmidt, Henk G; Dolmans, Diana H J M

2014-03-01

Even though peer process feedback is an often used tool to enhance the effectiveness of collaborative learning environments like PBL, the conditions under which it is best facilitated still need to be investigated. Therefore, this study investigated the effects of individual versus shared reflection and goal setting on students' individual contributions to the group and their academic achievement. In addition, the influence of prior knowledge on the effectiveness of peer feedback was studied. In this pretest-intervention-posttest study 242 first year students were divided into three conditions: condition 1 (individual reflection and goal setting), condition 2 (individual and shared reflection and goal setting), and condition 3 (control group). Results indicated that the quality of individual contributions to the tutorial group did not improve after receiving the peer feedback, nor did it differ between the three conditions. With regard to academic achievement, only males in conditions 1 and 2 showed better academic achievement compared with condition 3. However, there was no difference between both ways of reflection and goal setting with regard to achievement, indicating that both ways are equally effective. Nevertheless, it is still too early to conclude that peer feedback combined with reflection and goal setting is not effective in enhancing students' individual contributions. Students only had a limited number of opportunities to improve their contributions. Therefore, future research should investigate whether an increase in number of tutorial group meetings can enhance the effectiveness of peer feedback. In addition, the effect of quality of reflection and goal setting could be taken into consideration in future research.

Time to CUSUM: simplified reporting of outcomes in colorectal surgery.

PubMed

Bowles, Thomas A; Watters, David A

2007-07-01

Surgical audit has added value when outcomes can be compared and individual surgeons receive feedback. It is expected that surgeons compare their results with others in similar local practice, the published work, or peers from a craft group audit. Although feedback and comparison are worthy aims, for many surgeons the standards have not been agreed nor is there a craft group audit. The aim of this paper was to develop a reporting format for surgeons carrying out colorectal surgery in a regional hospital. The performance of 13 individual surgeons was analysed using a comprehensive colorectal audit with more than 600 cases. Feedback included caseload and type. Risk stratification of outcomes included; operation urgency, age and Physiological and Operative Severity Score for enUmeration of Mortality and Morbidity. Outcome measures were anastomotic leaks, end stoma rates, unplanned reoperations and mortality. Visual feedback included cumulative summation graphs for elective leaks, mortality and unplanned reoperations. A single A4 page of an individuals performance could be prepared that allowed comparison to the groups data overall. Alerts were set at 2-5% elective leaks, 4-7.5% mortality and 4-11% unplanned return to theatre. Cumulative summation graphs added to this allowed a visual guide to the key performance indicators. Surgeons need to determine how they will review their individual and collective results. These are equally important to the reported work. Detailed analysis of risk-stratified data should occur. Binary outcomes such as leak, mortality and unplanned reoperations may be followed by cumulative summation graphs. This provides a continually updated method of feedback, enabling immediate visual feedback of a surgeon's performance.

Memory-guided force control in healthy younger and older adults.

PubMed

Neely, Kristina A; Samimy, Shaadee; Blouch, Samantha L; Wang, Peiyuan; Chennavasin, Amanda; Diaz, Michele T; Dennis, Nancy A

2017-08-01

Successful performance of a memory-guided motor task requires participants to store and then recall an accurate representation of the motor goal. Further, participants must monitor motor output to make adjustments in the absence of visual feedback. The goal of this study was to examine memory-guided grip force in healthy younger and older adults and compare it to performance on behavioral tasks of working memory. Previous work demonstrates that healthy adults decrease force output as a function of time when visual feedback is not available. We hypothesized that older adults would decrease force output at a faster rate than younger adults, due to age-related deficits in working memory. Two groups of participants, younger adults (YA: N = 32, mean age 21.5 years) and older adults (OA: N = 33, mean age 69.3 years), completed four 20-s trials of isometric force with their index finger and thumb, equal to 25% of their maximum voluntary contraction. In the full-vision condition, visual feedback was available for the duration of the trial. In the no vision condition, visual feedback was removed for the last 12 s of each trial. Participants were asked to maintain constant force output in the absence of visual feedback. Participants also completed tasks of word recall and recognition and visuospatial working memory. Counter to our predictions, when visual feedback was removed, younger adults decreased force at a faster rate compared to older adults and the rate of decay was not associated with behavioral performance on tests of working memory.

SHORT-LIVED STAR-FORMING GIANT CLUMPS IN COSMOLOGICAL SIMULATIONS OF z Almost-Equal-To 2 DISKS

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

Genel, Shy; Genzel, Reinhard; Foerster Schreiber, Natascha M.

Many observed massive star-forming z Almost-Equal-To 2 galaxies are large disks that exhibit irregular morphologies, with Almost-Equal-To 1 kpc, Almost-Equal-To 10{sup 8}-10{sup 10}M{sub o-dot} clumps. We present the largest sample to date of high-resolution cosmological smoothed particle hydrodynamics simulations that zoom-in on the formation of individual M{sub *} Almost-Equal-To 10{sup 10.5}M{sub o-dot} galaxies in Almost-Equal-To 10{sup 12}M{sub o-dot} halos at z Almost-Equal-To 2. Our code includes strong stellar feedback parameterized as momentum-driven galactic winds. This model reproduces many characteristic features of this observed class of galaxies, such as their clumpy morphologies, smooth and monotonic velocity gradients, high gas fractions (f{submore » g} Almost-Equal-To 50%), and high specific star formation rates ({approx}>1 Gyr{sup -1}). In accord with recent models, giant clumps (M{sub clump} Almost-Equal-To (5 Multiplication-Sign 10{sup 8}-10{sup 9})M{sub o-dot}) form in situ via gravitational instabilities. However, the galactic winds are critical for their subsequent evolution. The giant clumps we obtain are short-lived and are disrupted by wind-driven mass loss. They do not virialize or migrate to the galaxy centers as suggested in recent work neglecting strong winds. By phenomenologically implementing the winds that are observed from high-redshift galaxies and in particular from individual clumps, our simulations reproduce well new observational constraints on clump kinematics and clump ages. In particular, the observation that older clumps appear closer to their galaxy centers is reproduced in our simulations, as a result of inside-out formation of the disks rather than inward clump migration.« less

A study of the relative effectiveness and cost of computerized information retrieval in the interactive mode

NASA Technical Reports Server (NTRS)

Smetana, F. O.; Furniss, M. A.; Potter, T. R.

1974-01-01

Results of a number of experiments to illuminate the relative effectiveness and costs of computerized information retrieval in the interactive mode are reported. It was found that for equal time spent in preparing the search strategy, the batch and interactive modes gave approximately equal recall and relevance. The interactive mode however encourages the searcher to devote more time to the task and therefore usually yields improved output. Engineering costs as a result are higher in this mode. Estimates of associated hardware costs also indicate that operation in this mode is more expensive. Skilled RECON users like the rapid feedback and additional features offered by this mode if they are not constrained by considerations of cost.

2-Step Maximum Likelihood Channel Estimation for Multicode DS-CDMA with Frequency-Domain Equalization

NASA Astrophysics Data System (ADS)

Kojima, Yohei; Takeda, Kazuaki; Adachi, Fumiyuki

Frequency-domain equalization (FDE) based on the minimum mean square error (MMSE) criterion can provide better downlink bit error rate (BER) performance of direct sequence code division multiple access (DS-CDMA) than the conventional rake combining in a frequency-selective fading channel. FDE requires accurate channel estimation. In this paper, we propose a new 2-step maximum likelihood channel estimation (MLCE) for DS-CDMA with FDE in a very slow frequency-selective fading environment. The 1st step uses the conventional pilot-assisted MMSE-CE and the 2nd step carries out the MLCE using decision feedback from the 1st step. The BER performance improvement achieved by 2-step MLCE over pilot assisted MMSE-CE is confirmed by computer simulation.

Base drive for paralleled inverter systems

NASA Technical Reports Server (NTRS)

Nagano, S. (Inventor)

1980-01-01

In a paralleled inverter system, a positive feedback current derived from the total current from all of the modules of the inverter system is applied to the base drive of each of the power transistors of all modules, thereby to provide all modules protection against open or short circuit faults occurring in any of the modules, and force equal current sharing among the modules during turn on of the power transistors.

Further Results on Sufficient LMI Conditions for H∞ Static Output Feedback Control of Discrete-Time Systems

NASA Astrophysics Data System (ADS)

Feng, Zhi-Yong; Xu, Li; Matsushita, Shin-Ya; Wu, Min

Further results on sufficient LMI conditions for H∞ static output feedback (SOF) control of discrete-time systems are presented in this paper, which provide some new insights into this issue. First, by introducing a slack variable with block-triangular structure and choosing the coordinate transformation matrix properly, the conservativeness of one kind of existing sufficient LMI condition is further reduced. Then, by introducing a slack variable with linear matrix equality constraint, another kind of sufficient LMI condition is proposed. Furthermore, the relation of these two kinds of LMI conditions are revealed for the first time through analyzing the effect of different choices of coordinate transformation matrices. Finally, a numerical example is provided to demonstrate the effectiveness and merits of the proposed methods.

Route guidance strategies revisited: Comparison and evaluation in an asymmetric two-route traffic network

NASA Astrophysics Data System (ADS)

He, Zhengbing; Chen, Bokui; Jia, Ning; Guan, Wei; Lin, Benchuan; Wang, Binghong

2014-12-01

To alleviate traffic congestion, a variety of route guidance strategies have been proposed for intelligent transportation systems. A number of strategies are introduced and investigated on a symmetric two-route traffic network over the past decade. To evaluate the strategies in a more general scenario, this paper conducts eight prevalent strategies on an asymmetric two-route traffic network with different slowdown behaviors on alternative routes. The results show that only mean velocity feedback strategy (MVFS) is able to equalize travel time, i.e. approximate user optimality (UO); while the others fail due to incapability of establishing relations between the feedback parameters and travel time. The paper helps better understand these strategies, and suggests MVFS if the authority intends to achieve user optimality.

Quantifying the Relative Contributions of Divisive and Subtractive Feedback to Rhythm Generation

PubMed Central

Tabak, Joël; Rinzel, John; Bertram, Richard

2011-01-01

Biological systems are characterized by a high number of interacting components. Determining the role of each component is difficult, addressed here in the context of biological oscillations. Rhythmic behavior can result from the interplay of positive feedback that promotes bistability between high and low activity, and slow negative feedback that switches the system between the high and low activity states. Many biological oscillators include two types of negative feedback processes: divisive (decreases the gain of the positive feedback loop) and subtractive (increases the input threshold) that both contribute to slowly move the system between the high- and low-activity states. Can we determine the relative contribution of each type of negative feedback process to the rhythmic activity? Does one dominate? Do they control the active and silent phase equally? To answer these questions we use a neural network model with excitatory coupling, regulated by synaptic depression (divisive) and cellular adaptation (subtractive feedback). We first attempt to apply standard experimental methodologies: either passive observation to correlate the variations of a variable of interest to system behavior, or deletion of a component to establish whether a component is critical for the system. We find that these two strategies can lead to contradictory conclusions, and at best their interpretive power is limited. We instead develop a computational measure of the contribution of a process, by evaluating the sensitivity of the active (high activity) and silent (low activity) phase durations to the time constant of the process. The measure shows that both processes control the active phase, in proportion to their speed and relative weight. However, only the subtractive process plays a major role in setting the duration of the silent phase. This computational method can be used to analyze the role of negative feedback processes in a wide range of biological rhythms. PMID:21533065

Are All Competencies Equal in the Eyes of Residents? A Multicenter Study of Emergency Medicine Residents’ Interest in Feedback

PubMed Central

Bentley, Suzanne; Hu, Kevin; Messman, Anne; Moadel, Tiffany; Khandelwal, Sorabh; Streich, Heather; Noelker, Joan

2017-01-01

Introduction Feedback, particularly real-time feedback, is critical to resident education. The emergency medicine (EM) milestones were developed in 2012 to enhance resident assessment, and many programs use them to provide focused resident feedback. The purpose of this study was to evaluate EM residents’ level of interest in receiving real-time feedback on each of the 23 competencies/sub-competencies. Methods This was a multicenter cross-sectional study of EM residents. We surveyed participants on their level of interest in receiving real-time on-shift feedback on each of the 23 competencies/sub-competencies. Anonymous paper or computerized surveys were distributed to residents at three four-year training programs and three three-year training programs with a total of 223 resident respondents. Residents rated their level of interest in each milestone on a six-point Likert-type response scale. We calculated average level of interest for each of the 23 sub-competencies, for all 223 respondents and separately by postgraduate year (PGY) levels of training. One-way analyses of variance were performed to determine if there were differences in ratings by level of training. Results The overall survey response rate across all institutions was 82%. Emergency stabilization had the highest mean rating (5.47/6), while technology had the lowest rating (3.24/6). However, we observed no differences between levels of training on any of the 23 competencies/sub-competencies. Conclusion Residents seem to ascribe much more value in receiving feedback on domains involving high-risk, challenging procedural skills as compared to low-risk technical and communication skills. Further studies are necessary to determine whether residents’ perceived importance of competencies/sub-competencies needs to be considered when developing an assessment or feedback program based on these 23 EM competencies/sub-competencies. PMID:28116012

Precluding nonlinear ISI in direct detection long-haul fiber optic systems

NASA Technical Reports Server (NTRS)

Swenson, Norman L.; Shoop, Barry L.; Cioffi, John M.

1991-01-01

Long-distance, high-rate fiber optic systems employing directly modulated 1.55-micron single-mode lasers and conventional single-mode fiber suffer severe intersymbol interference (ISI) with a large nonlinear component. A method of reducing the nonlinearity of the ISI, thereby making linear equalization more viable, is investigated. It is shown that the degree of nonlinearity is highly dependent on the choice of laser bias current, and that in some cases the ISI nonlinearity can be significantly reduced by biasing the laser substantially above threshold. Simulation results predict that an increase in signal-to-nonlinear-distortion ratio as high as 25 dB can be achieved for synchronously spaced samples at an optimal sampling phase by increasing the bias current from 1.2 times threshold to 3.5 times threshold. The high SDR indicates that a linear tapped delay line equalizer could be used to mitigate ISI. Furthermore, the shape of the pulse response suggests that partial response precoding and digital feedback equalization would be particularly effective for this channel.

Extended Horizon Liftings for Periodic Gain Adjustments in Control Systems, and for Equalization of Communication Channels

NASA Technical Reports Server (NTRS)

Bayard, David S. (Inventor)

1996-01-01

Periodic gain adjustment in plants of irreducible order, n, or for equalization of communications channels is effected in such a way that the plant (system) appears to be minimum phase by choosing a horizon time N greater then n of liftings in periodic input and output windows Pu and Py, respectively, where N is an integer chosen to define the extent (length) of each of the windows Pu and Py, and n is the order of an irreducible input/output plant. The plant may be an electrical, mechanical or chemical system, in which case output tracking (OT) is carried out for feedback control or a communication channel, in which case input tracking (IT) is carried out. Conditions for OT are distinct from IT in terms of zero annihilation, namely for OT and of IT, where the OT conditions are intended for gain adjustments in the control system, and IT conditions are intended for equalization for communication channels.

Perceptual support promotes strategy generation: Evidence from equation solving.

PubMed

Alibali, Martha W; Crooks, Noelle M; McNeil, Nicole M

2017-08-30

Over time, children shift from using less optimal strategies for solving mathematics problems to using better ones. But why do children generate new strategies? We argue that they do so when they begin to encode problems more accurately; therefore, we hypothesized that perceptual support for correct encoding would foster strategy generation. Fourth-grade students solved mathematical equivalence problems (e.g., 3 + 4 + 5 = 3 + __) in a pre-test. They were then randomly assigned to one of three perceptual support conditions or to a Control condition. Participants in all conditions completed three mathematical equivalence problems with feedback about correctness. Participants in the experimental conditions received perceptual support (i.e., highlighting in red ink) for accurately encoding the equal sign, the right side of the equation, or the numbers that could be added to obtain the correct solution. Following this intervention, participants completed a problem-solving post-test. Among participants who solved the problems incorrectly at pre-test, those who received perceptual support for correctly encoding the equal sign were more likely to generate new, correct strategies for solving the problems than were those who received feedback only. Thus, perceptual support for accurate encoding of a key problem feature promoted generation of new, correct strategies. Statement of Contribution What is already known on this subject? With age and experience, children shift to using more effective strategies for solving math problems. Problem encoding also improves with age and experience. What the present study adds? Support for encoding the equal sign led children to generate correct strategies for solving equations. Improvements in problem encoding are one source of new strategies. © 2017 The British Psychological Society.

Constraining the slip distribution and fault geometry of the Mw 7.9, 3 November 2002, Denali fault earthquake with Interferometric Synthetic Aperture Radar and Global Positioning System data

USGS Publications Warehouse

Wright, Tim J.; Lu, Z.; Wicks, Charles

2004-01-01

The Mw 7.9, Denali fault earthquake (DFE) is the largest continental strike-slip earthquake to occur since the development of Interferometric Synthetic Aperture Radar (InSAR). We use five interferograms, constructed using radar images from the Canadian Radarsat-1 satellite, to map the surface deformation at the western end of the fault rupture. Additional geodetic data are provided by displacements observed at 40 campaign and continuous Global Positioning System (GPS) sites. We use the data to determine the geometry of the Susitna Glacier fault, thrusting on which initiated the DFE, and to determine a slip model for the entire event that is consistent with both the InSAR and GPS data. We find there was an average of 7.3 ± 0.4 m slip on the Susitna Glacier fault, between 1 and 9.5 km depth on a 29 km long fault that dips north at 41 ± 0.7° and has a surface projection close to the mapped rupture. On the Denali fault, a simple model with large slip patches finds a maximum of 8.7 ± 0.7 m of slip between the surface and 14.3 ± 0.2 km depth. A more complex distributed slip model finds a peak of 12.5 ± 0.8 m in the upper 4 km, significantly higher than the observed surface slip. We estimate a geodetic moment of 670 ± 10 × 1018 N m (Mw 7.9), consistent with seismic estimates. Lack of preseismic data resulted in an absence of InSAR coverage for the eastern half of the DFE rupture. A dedicated geodetic InSAR mission could obviate coverage problems in the future.

Sensor Data Fusion for Body State Estimation in a Bipedal Robot and Its Feedback Control Application for Stable Walking

PubMed Central

Chen, Ching-Pei; Chen, Jing-Yi; Huang, Chun-Kai; Lu, Jau-Ching; Lin, Pei-Chun

2015-01-01

We report on a sensor data fusion algorithm via an extended Kalman filter for estimating the spatial motion of a bipedal robot. Through fusing the sensory information from joint encoders, a 6-axis inertial measurement unit and a 2-axis inclinometer, the robot’s body state at a specific fixed position can be yielded. This position is also equal to the CoM when the robot is in the standing posture suggested by the detailed CAD model of the robot. In addition, this body state is further utilized to provide sensory information for feedback control on a bipedal robot with walking gait. The overall control strategy includes the proposed body state estimator as well as the damping controller, which regulates the body position state of the robot in real-time based on instant and historical position tracking errors. Moreover, a posture corrector for reducing unwanted torque during motion is addressed. The body state estimator and the feedback control structure are implemented in a child-size bipedal robot and the performance is experimentally evaluated. PMID:25734644

On the Application of Time-Reversed Space-Time Block Code to Aeronautical Telemetry

DTIC Science & Technology

2014-06-01

Keying (SOQPSK), bit error rate (BER), Orthogonal Frequency Division Multiplexing ( OFDM ), Generalized time-reversed space-time block codes (GTR-STBC) 16...Alamouti code [4]) is optimum [2]. Although OFDM is generally applied on a per subcarrier basis in frequency selective fading, it is not a viable...Calderbank, “Finite-length MIMO decision feedback equal- ization for space-time block-coded signals over multipath-fading channels,” IEEE Transac- tions on

Advanced digital signal processing for short-haul and access network

NASA Astrophysics Data System (ADS)

Zhang, Junwen; Yu, Jianjun; Chi, Nan

2016-02-01

Digital signal processing (DSP) has been proved to be a successful technology recently in high speed and high spectrum-efficiency optical short-haul and access network, which enables high performances based on digital equalizations and compensations. In this paper, we investigate advanced DSP at the transmitter and receiver side for signal pre-equalization and post-equalization in an optical access network. A novel DSP-based digital and optical pre-equalization scheme has been proposed for bandwidth-limited high speed short-distance communication system, which is based on the feedback of receiver-side adaptive equalizers, such as least-mean-squares (LMS) algorithm and constant or multi-modulus algorithms (CMA, MMA). Based on this scheme, we experimentally demonstrate 400GE on a single optical carrier based on the highest ETDM 120-GBaud PDM-PAM-4 signal, using one external modulator and coherent detection. A line rate of 480-Gb/s is achieved, which enables 20% forward-error correction (FEC) overhead to keep the 400-Gb/s net information rate. The performance after fiber transmission shows large margin for both short range and metro/regional networks. We also extend the advanced DSP for short haul optical access networks by using high order QAMs. We propose and demonstrate a high speed multi-band CAP-WDM-PON system on intensity modulation, direct detection and digital equalizations. A hybrid modified cascaded MMA post-equalization schemes are used to equalize the multi-band CAP-mQAM signals. Using this scheme, we successfully demonstrates 550Gb/s high capacity WDMPON system with 11 WDM channels, 55 sub-bands, and 10-Gb/s per user in the downstream over 40-km SMF.

The biomass burning contribution to climate-carbon-cycle feedback

NASA Astrophysics Data System (ADS)

Harrison, Sandy P.; Bartlein, Patrick J.; Brovkin, Victor; Houweling, Sander; Kloster, Silvia; Prentice, I. Colin

2018-05-01

Temperature exerts strong controls on the incidence and severity of fire. All else equal, warming is expected to increase fire-related carbon emissions, and thereby atmospheric CO2. But the magnitude of this feedback is very poorly known. We use a single-box model of the land biosphere to quantify this positive feedback from satellite-based estimates of biomass burning emissions for 2000-2014 CE and from sedimentary charcoal records for the millennium before the industrial period. We derive an estimate of the centennial-scale feedback strength of 6.5 ± 3.4 ppm CO2 per degree of land temperature increase, based on the satellite data. However, this estimate is poorly constrained, and is largely driven by the well-documented dependence of tropical deforestation and peat fires (primarily anthropogenic) on climate variability patterns linked to the El Niño-Southern Oscillation. Palaeo-data from pre-industrial times provide the opportunity to assess the fire-related climate-carbon-cycle feedback over a longer period, with less pervasive human impacts. Past biomass burning can be quantified based on variations in either the concentration and isotopic composition of methane in ice cores (with assumptions about the isotopic signatures of different methane sources) or the abundances of charcoal preserved in sediments, which reflect landscape-scale changes in burnt biomass. These two data sources are shown here to be coherent with one another. The more numerous data from sedimentary charcoal, expressed as normalized anomalies (fractional deviations from the long-term mean), are then used - together with an estimate of mean biomass burning derived from methane isotope data - to infer a feedback strength of 5.6 ± 3.2 ppm CO2 per degree of land temperature and (for a climate sensitivity of 2.8 K) a gain of 0.09 ± 0.05. This finding indicates that the positive carbon cycle feedback from increased fire provides a substantial contribution to the overall climate-carbon-cycle feedback on centennial timescales. Although the feedback estimates from palaeo- and satellite-era data are in agreement, this is likely fortuitous because of the pervasive influence of human activities on fire regimes during recent decades.

Feedback and feedforward locomotor adaptations to ankle-foot load in people with incomplete spinal cord injury.

PubMed

Gordon, Keith E; Wu, Ming; Kahn, Jennifer H; Schmit, Brian D

2010-09-01

Humans with spinal cord injury (SCI) modulate locomotor output in response to limb load. Understanding the neural control mechanisms responsible for locomotor adaptation could provide a framework for selecting effective interventions. We quantified feedback and feedforward locomotor adaptations to limb load modulations in people with incomplete SCI. While subjects airstepped (stepping performed with kinematic assistance and 100% bodyweight support), a powered-orthosis created a dorisflexor torque during the "stance phase" of select steps producing highly controlled ankle-load perturbations. When given repetitive, stance phase ankle-load, the increase in hip extension work, 0.27 J/kg above baseline (no ankle-load airstepping), was greater than the response to ankle-load applied during a single step, 0.14 J/kg (P = 0.029). This finding suggests that, at the hip, subjects produced both feedforward and feedback locomotor modulations. We estimate that, at the hip, the locomotor response to repetitive ankle-load was modulated almost equally by ongoing feedback and feedforward adaptations. The majority of subjects also showed after-effects in hip kinetic patterns that lasted 3 min in response to repetitive loading, providing additional evidence of feedforward locomotor adaptations. The magnitude of the after-effect was proportional to the response to repetitive ankle-foot load (R(2) = 0.92). In contrast, increases in soleus EMG amplitude were not different during repetitive and single-step ankle-load exposure, suggesting that ankle locomotor modulations were predominately feedback-based. Although subjects made both feedback and feedforward locomotor adaptations to changes in ankle-load, between-subject variations suggest that walking function may be related to the ability to make feedforward adaptations.

Interactions of forest disturbance-recovery dynamics with a changing climate

NASA Astrophysics Data System (ADS)

Anderson-Teixeira, K. J.; Miller, A. D.; Tepley, A. J.; Bennett, A. C.; Wang, M.

2015-12-01

As the climate changes, altered disturbance-recovery dynamics in forests worldwide are likely to result in significant biogeochemical and biophysical feedbacks to the climate system. Climate shapes forest disturbance events including tree mortality and fire, with consequent climate feedbacks. For instance, in forests globally, drought increases tree mortality rates, having a stronger impact on larger trees and resulting in greater feedbacks to climate change than would occur if drought sensitivities were equal across tree size classes. Forest regeneration and associated biogeochemical and biophysical feedbacks are also shaped by climate: across the tropics the rate of biomass accumulation is faster in everwet than in seasonally dry climates, and in the Klamath region (N California / S Oregon), post-fire vegetation dynamics and microclimate are shaped by aridity. Forest recovery dynamics will be affected by elevated CO2 and climate change; for instance, models predict that forest regeneration rate, successional dynamics, and climate feedbacks will all be altered under elevated CO2. In combination, climatic impacts on disturbance and recovery can result in dramatic shifts in forest cover on the landscape level. For instance, in fire-prone forested landscapes, forest cover decreases with increasing frequency of high-severity fire and decreasing forest recovery rate, both of which could be altered by climate change, producing rapid loss of forest on the landscape level. Such effects may be amplified by the existence of alternative stable states, which can cause systems to experience non-reversible changes in cover type. Critical transitions in landscape-level forest cover would have significant biogeochemical and biophysical feedbacks. Thus, altered disturbance-recovery dynamics under a changing climate may have sudden and dramatic impacts on forest-climate interactions.

The use of objective structured self-assessment and peer-feedback (OSSP) for learning communication skills: evaluation using a controlled trial.

PubMed

Perera, Jennifer; Mohamadou, Galy; Kaur, Satpal

2010-05-01

Feedback is essential to guide students towards expected performance goals. The usefulness of teacher feedback on improving communication skills (CS) has been well documented. It has been proposed that self-assessment and peer-feedback has an equally important role to play in enhancing learning. This is the focus of this study. Objectively structured self-assessment and peer feedback (OSSP) was incorporated into small group CS teaching sessions of a group of semester one medical students who were learning CS for the first time, to minimise the influence of previous educational interventions. A control group matched for academic performance, gender and age was used to enable parallel evaluation of the innovation. A reflective log containing closed and open ended questions was used for OSSP. Facilitators and simulated patients provided feedback to students in both groups during CS learning as per routine practice. Student perceptions on OSSP and acceptability as a learning method were explored using a questionnaire. CS were assessed in both groups using objective structured clinical examination (OSCE) as per routine practice and assessors were blinded as to which group the student belonged. Mean total score and scores for specific areas of interview skills were significantly higher in the experimental group. Analysis of the questionnaire data showed that students gained fresh insights into specific areas such as empathy, addressing patients' concerns and interview style during OSSP which clearly corroborated the specific differences in scores. The free text comments were highly encouraging as to acceptability of OSSP, in spite of 67% being never exposed to formal self- and peer-assessment during pre-university studies. OSSP promotes effective CS learning and learner acceptability is high.

The predictability of frequency-altered auditory feedback changes the weighting of feedback and feedforward input for speech motor control.

PubMed

Scheerer, Nichole E; Jones, Jeffery A

2014-12-01

Speech production requires the combined effort of a feedback control system driven by sensory feedback, and a feedforward control system driven by internal models. However, the factors that dictate the relative weighting of these feedback and feedforward control systems are unclear. In this event-related potential (ERP) study, participants produced vocalisations while being exposed to blocks of frequency-altered feedback (FAF) perturbations that were either predictable in magnitude (consistently either 50 or 100 cents) or unpredictable in magnitude (50- and 100-cent perturbations varying randomly within each vocalisation). Vocal and P1-N1-P2 ERP responses revealed decreases in the magnitude and trial-to-trial variability of vocal responses, smaller N1 amplitudes, and shorter vocal, P1 and N1 response latencies following predictable FAF perturbation magnitudes. In addition, vocal response magnitudes correlated with N1 amplitudes, vocal response latencies, and P2 latencies. This pattern of results suggests that after repeated exposure to predictable FAF perturbations, the contribution of the feedforward control system increases. Examination of the presentation order of the FAF perturbations revealed smaller compensatory responses, smaller P1 and P2 amplitudes, and shorter N1 latencies when the block of predictable 100-cent perturbations occurred prior to the block of predictable 50-cent perturbations. These results suggest that exposure to large perturbations modulates responses to subsequent perturbations of equal or smaller size. Similarly, exposure to a 100-cent perturbation prior to a 50-cent perturbation within a vocalisation decreased the magnitude of vocal and N1 responses, but increased P1 and P2 latencies. Thus, exposure to a single perturbation can affect responses to subsequent perturbations. © 2014 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

The effect of standardized patient feedback in teaching surgical residents informed consent: results of a pilot study.

PubMed

Leeper-Majors, Kristine; Veale, James R; Westbrook, Thomas S; Reed, Kendall

2003-01-01

The purpose of this pilot study was to determine the effectiveness of using feedback from a standardized patient (SP) to teach a surgical resident (SR) informed consent (IC) protocol. Four general case types of increasing difficulty were tested in a longitudinal experimental design format. The four types of cases were appendectomy, cholecystectomy, colorectal cancer, and breast cancer. Eight SRs of varying years of completion in medical school served as subjects-four in the experimental group (received performance feedback from an SP) and four in the control group (received no SP feedback). Both the control and experimental groups participated in two patient encounters per case type. The first patient encounter served as the pretest, and the second patient encounter was the posttest. In each encounter, an SP rated the resident on 14 measures using an open-ended seven-point rating scale adopted and modified from the Brown University Interpersonal Skill Evaluation (BUISE). Each resident also reviewed a videotape of an expert giving IC between pretest and the posttest for basic instructional protocol. Random stratified sampling was used to equally distribute the residents by postgraduate years. A total of 16 SPs were used in this study. All patient/SR encounters were videotaped. There was a statistically significant overall change--pretest to posttest and across cases (p = 0.001). The group effect was statistically significant (p = 0.000), with the experimental group averaging about 10 points greater than the control group. Standardized patient feedback is an effective modality in teaching surgical residents informed consent protocol. This conclusion is tentative, due to the limitations of sample size. The results of this study support continued research on the effects of standardized patient feedback to teach informed consent to surgical residents.

Merging molecular mechanism and evolution: theory and computation at the interface of biophysics and evolutionary population genetics

PubMed Central

Serohijos, Adrian W.R.; Shakhnovich, Eugene I.

2014-01-01

The variation among sequences and structures in nature is both determined by physical laws and by evolutionary history. However, these two factors are traditionally investigated by disciplines with different emphasis and philosophy—molecular biophysics on one hand and evolutionary population genetics in another. Here, we review recent theoretical and computational approaches that address the critical need to integrate these two disciplines. We first articulate the elements of these integrated approaches. Then, we survey their contribution to our mechanistic understanding of molecular evolution, the polymorphisms in coding region, the distribution of fitness effects (DFE) of mutations, the observed folding stability of proteins in nature, and the distribution of protein folds in genomes. PMID:24952216

Merging molecular mechanism and evolution: theory and computation at the interface of biophysics and evolutionary population genetics.

PubMed

Serohijos, Adrian W R; Shakhnovich, Eugene I

2014-06-01

The variation among sequences and structures in nature is both determined by physical laws and by evolutionary history. However, these two factors are traditionally investigated by disciplines with different emphasis and philosophy-molecular biophysics on one hand and evolutionary population genetics in another. Here, we review recent theoretical and computational approaches that address the crucial need to integrate these two disciplines. We first articulate the elements of these approaches. Then, we survey their contribution to our mechanistic understanding of molecular evolution, the polymorphisms in coding region, the distribution of fitness effects (DFE) of mutations, the observed folding stability of proteins in nature, and the distribution of protein folds in genomes. Copyright © 2014 Elsevier Ltd. All rights reserved.

On Priming Action: Conclusions from a Meta-Analysis of the Behavioral Effects of Incidentally-Presented Words

PubMed Central

Weingarten, Evan; Chen, Qijia; McAdams, Maxwell; Yi, Jessica; Hepler, Justin; Albarracin, Dolores

2016-01-01

This paper presents a summary of the conclusions drawn from a meta-analysis of the behavioral impact of presenting words connected to an action or a goal representation (Weingarten et al., 2016). The average and distribution of 352 effect sizes from 133 studies (84 reports) revealed a small behavioral priming effect (dFE = 0.332, dRE= 0.352), which was robust across methodological procedures and only minimally biased by the publication of positive (vs. negative) results. More valued behavior or goal concepts (e.g., associated with important outcomes or values) were associated with stronger priming effects than were less valued behaviors. In addition, opportunities for goal satisfaction appeared to decrease priming effects. PMID:27957520

Chaos control by electric current in an enzymatic reaction.

PubMed

Lekebusch, A; Förster, A; Schneider, F W

1996-09-01

We apply the continuous delayed feedback method of Pyragas to control chaos in the enzymatic Peroxidase-Oxidase (PO) reaction, using the electric current as the control parameter. At each data point in the time series, a time delayed feedback function applies a small amplitude perturbation to inert platinum electrodes, which causes redox processes on the surface of the electrodes. These perturbations are calculated as the difference between the previous (time delayed) signal and the actual signal. Unstable periodic P1, 1(1), and 1(2) orbits (UPOs) were stabilized in the CSTR (continuous stirred tank reactor) experiments. The stabilization is demonstrated by at least three conditions: A minimum in the experimental dispersion function, the equality of the delay time with the period of the stabilized attractor and the embedment of the stabilized periodic attractor in the chaotic attractor.

[Mid-infrared distributed-feedback quantum cascade laser-based photoacoustic detection of trace methane gas].

PubMed

Tan, Song; Liu, Wan-feng; Wang, Li-jun; Zhang, Jin-chuan; Li, Lu; Liu, Jun-qi; Liu, Feng-qi; Wang, Zhan-guo

2012-05-01

There have been considerable interests in methane detection based on infrared absorption spectroscopy for industrial and environment monitoring. The authors report on the realization of photoacoustic detection of methane (CH4) using mid-infrared distributed-feedback quantum cascade laser (DFB-QCL). The absorption line at 1316.83 cm(-1) was selected for CH4 detection, which can be reached by the self-manufactured DFB-QCL source operating in pulsed mode near 7.6 microm at room-temperature. The CH4 gas is filled to a Helmholtz resonant photoacoustic cell, which was equipped with a commercial electret microphone. The DFB-QCL was operated at 234 Hz with an 80 mW optical peak power. A detection limit of 189 parts per billion in volume was derived when the signal-to-noise ratio equaled 1.

Assessment of Haptic Interaction for Home-Based Physical Tele-Therapy using Wearable Devices and Depth Sensors.

PubMed

Barmpoutis, Angelos; Alzate, Jose; Beekhuizen, Samantha; Delgado, Horacio; Donaldson, Preston; Hall, Andrew; Lago, Charlie; Vidal, Kevin; Fox, Emily J

2016-01-01

In this paper a prototype system is presented for home-based physical tele-therapy using a wearable device for haptic feedback. The haptic feedback is generated as a sequence of vibratory cues from 8 vibrator motors equally spaced along an elastic wearable band. The motors guide the patients' movement as they perform a prescribed exercise routine in a way that replaces the physical therapists' haptic guidance in an unsupervised or remotely supervised home-based therapy session. A pilot study of 25 human subjects was performed that focused on: a) testing the capability of the system to guide the users in arbitrary motion paths in the space and b) comparing the motion of the users during typical physical therapy exercises with and without haptic-based guidance. The results demonstrate the efficacy of the proposed system.

A Research Study to Develop an Army-Wide Equal Opportunity Training Model. Volume 1

DTIC Science & Technology

1979-03-01

three areas is detailed below. Personal Discrimination Personal racism (or sexism ) is defined in AR 600-21 in terms of " The acting out of prejudices by...example (6) Diagnosing unit climate on racism / sexism issues (a) unit survey (b) informal feedback (c) personal observation (7) Developing...various communities out of which the modem serviceman emerges. • Group Leadership Practicum-to provide the student with the theory and practice in

On Optimum Power Allocation for Multi-Antenna Wideband Helicopter-to-Ground Communications

DTIC Science & Technology

2014-03-01

optimum [1]. In frequency selective fading, the general approach is to use OFDM and apply these techniques on a per subcarrier basis. This work was...Contracting Office under contract W900KK-09-C-0016. Given the constraints described above, OFDM is often of limited interest in helicopter-to-ground...Naguib, and R. Calderbank, “Finite-length MIMO decision feedback equalization for space-time block-coded signals over multipath-fading channels,” IEEE

Creating a performance appraisal template for pharmacy technicians using the method of equal-appearing intervals.

PubMed

Desselle, Shane P; Vaughan, Melissa; Faria, Thomas

2002-01-01

To design a highly quantitative template for the evaluation of community pharmacy technicians' job performance that enables managers to provide sufficient feedback and fairly allocate organizational rewards. Two rounds of interviews with two convenience samples of community pharmacists and pharmacy technicians were conducted. The interview in phase 1 was qualitative, and responses were used to design the second interview protocol. During the phase 2 interviews, a new group of respondents ranked technicians' job responsibilities, identified through the initial interviewees' responses, using scales the researchers had designed using an interval-level scaling technique called equal-appearing intervals. Chain and independent pharmacies. Phase 1-20 pharmacists and 20 technicians from chain and independent pharmacies; phase 2-20 pharmacists and 9 technicians from chain and independent pharmacies. Ratings of the importance of technician practice functions and corresponding responsibilities. Weights were calculated for each practice function. A weighted list of practice functions was developed, and this may serve as a performance evaluation template. Customer service-related activities were judged by pharmacists and technicians alike to be the most important technician functions. Many pharmacies either lack formal performance appraisal systems or fail to implement them properly. Technicians may desire more consistent feedback from pharmacists and value information that may lead to organizational rewards. Using a weighted, behaviorally anchored performance appraisal system may help pharmacists and pharmacy managers meet these demands.

Using a Root Cause Analysis Curriculum for Practice-Based Learning and Improvement in General Surgery Residency.

PubMed

Ramanathan, Rajesh; Duane, Therese M; Kaplan, Brian J; Farquhar, Doris; Kasirajan, Vigneshwar; Ferrada, Paula

2015-01-01

To describe and evaluate a root cause analysis (RCA)-based educational curriculum for quality improvement (QI) practice-based learning and implementation in general surgery residency. A QI curriculum was designed using RCA and spaced-learning approaches to education. The program included a didactic session about the RCA methodology. Resident teams comprising multiple postgraduate years then selected a personal complication, completed an RCA, and presented the findings to the Department of Surgery. Mixed methods consisting of quantitative assessment of performance and qualitative feedback about the program were used to assess the value, strengths, and limitations of the program. Urban tertiary academic medical center. General surgery residents, faculty, and medical students. An RCA was completed by 4 resident teams for the following 4 adverse outcomes: postoperative neck hematoma, suboptimal massive transfusion for trauma, venous thromboembolism, and decubitus ulcer complications. Quantitative peer assessment of their performance revealed proficiency in selecting an appropriate case, defining the central problem, identifying root causes, and proposing solutions. During the qualitative feedback assessment, residents noted value of the course, with the greatest limitation being time constraints and equal participation. An RCA-based curriculum can provide general surgery residents with QI exposure and training that they value. Barriers to successful implementation include time restrictions and equal participation from all involved members. Copyright © 2015 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

The effects of augmented visual feedback during balance training in Parkinson's disease: study design of a randomized clinical trial.

PubMed

van den Heuvel, Maarten R C; van Wegen, Erwin E H; de Goede, Cees J T; Burgers-Bots, Ingrid A L; Beek, Peter J; Daffertshofer, Andreas; Kwakkel, Gert

2013-10-04

Patients with Parkinson's disease often suffer from reduced mobility due to impaired postural control. Balance exercises form an integral part of rehabilitative therapy but the effectiveness of existing interventions is limited. Recent technological advances allow for providing enhanced visual feedback in the context of computer games, which provide an attractive alternative to conventional therapy. The objective of this randomized clinical trial is to investigate whether a training program capitalizing on virtual-reality-based visual feedback is more effective than an equally-dosed conventional training in improving standing balance performance in patients with Parkinson's disease. Patients with idiopathic Parkinson's disease will participate in a five-week balance training program comprising ten treatment sessions of 60 minutes each. Participants will be randomly allocated to (1) an experimental group that will receive balance training using augmented visual feedback, or (2) a control group that will receive balance training in accordance with current physical therapy guidelines for Parkinson's disease patients. Training sessions consist of task-specific exercises that are organized as a series of workstations. Assessments will take place before training, at six weeks, and at twelve weeks follow-up. The functional reach test will serve as the primary outcome measure supplemented by comprehensive assessments of functional balance, posturography, and electroencephalography. We hypothesize that balance training based on visual feedback will show greater improvements on standing balance performance than conventional balance training. In addition, we expect that learning new control strategies will be visible in the co-registered posturographic recordings but also through changes in functional connectivity.

Extended horizon lifting for periodic gain adjustment in control systems, and for equalization of communication channels

NASA Technical Reports Server (NTRS)

Bayard, David S. (Inventor)

1994-01-01

Periodic gain adjustment in plants of irreducible order, n, or for equalization of communications channels is effected in such a way that the plant (system) appears to be minimum phase by choosing a horizon time N is greater than n of liftings in periodic input and output windows rho sub u and rho sub y, respectively, where N is an integer chosen to define the extent (length) of each of the windows rho sub u and rho sub y, and n is the order of an irreducible input/output plant. The plant may be an electrical, mechanical, or chemical system, in which case output tracking (OT) is carried out for feedback control or a communication channel, in which case input tracking (IT) is performed. Conditions for OT are distinct from IT in terms of zero annihilation, namely H(sub s)H(sub s)(sup +) = I for OT and H(sub s)H(sub s)(sup +) = I of IT, where the OT conditions are intended for gain adjustments in the control system, and IT conditions are intended for equalization for communication channels.

Approaching system equilibrium with accurate or not accurate feedback information in a two-route system

NASA Astrophysics Data System (ADS)

Zhao, Xiao-mei; Xie, Dong-fan; Li, Qi

2015-02-01

With the development of intelligent transport system, advanced information feedback strategies have been developed to reduce traffic congestion and enhance the capacity. However, previous strategies provide accurate information to travelers and our simulation results show that accurate information brings negative effects, especially in delay case. Because travelers prefer to the best condition route with accurate information, and delayed information cannot reflect current traffic condition but past. Then travelers make wrong routing decisions, causing the decrease of the capacity and the increase of oscillations and the system deviating from the equilibrium. To avoid the negative effect, bounded rationality is taken into account by introducing a boundedly rational threshold BR. When difference between two routes is less than the BR, routes have equal probability to be chosen. The bounded rationality is helpful to improve the efficiency in terms of capacity, oscillation and the gap deviating from the system equilibrium.

Nonlinear dynamics of autonomous vehicles with limits on acceleration

NASA Astrophysics Data System (ADS)

Davis, L. C.

2014-07-01

The stability of autonomous vehicle platoons with limits on acceleration and deceleration is determined. If the leading-vehicle acceleration remains within the limits, all vehicles in the platoon remain within the limits when the relative-velocity feedback coefficient is equal to the headway time constant [k=1/h]. Furthermore, if the sensitivity α>1/h, no collisions occur. String stability for small perturbations is assumed and the initial condition is taken as the equilibrium state. Other values of k and α that give stability with no collisions are found from simulations. For vehicles with non-negligible mechanical response, simulations indicate that the acceleration-feedback-control gain might have to be dynamically adjusted to obtain optimal performance as the response time changes with engine speed. Stability is demonstrated for some perturbations that cause initial acceleration or deceleration greater than the limits, yet do not cause collisions.

How Toddlers Acquire and Transfer Tool Knowledge: Developmental Changes and the Role of Executive Functions.

PubMed

Pauen, Sabina; Bechtel-Kuehne, Sabrina

2016-07-01

This report investigates tool learning and its relations to executive functions (EFs) in toddlers. In Study 1 (N = 93), 18-, 20-, 22-, and 24-month-old children learned equally well to choose a correct tool from observation, whereas performance based on feedback improved with age. Knowledge transfer showed significant progress after 22 months of age: Older children ignored irrelevant features more easily and adjusted their behavior more flexibly. Study 2 (N = 62) revealed that spontaneous transfer in 22- to 24-month-olds was related to set-shifting skills and response inhibition. Flexible adaptation to feedback correlated with working-memory capacity. These findings suggest that toddlerhood is a highly dynamic phase of tool learning and that EFs are related to transfer performance at this age. © 2016 The Authors. Child Development © 2016 Society for Research in Child Development, Inc.

Digital phase-locked-loop speed sensor for accuracy improvement in analog speed controls. [feedback control and integrated circuits

NASA Technical Reports Server (NTRS)

Birchenough, A. G.

1975-01-01

A digital speed control that can be combined with a proportional analog controller is described. The stability and transient response of the analog controller were retained and combined with the long-term accuracy of a crystal-controlled integral controller. A relatively simple circuit was developed by using phase-locked-loop techniques and total error storage. The integral digital controller will maintain speed control accuracy equal to that of the crystal reference oscillator.

Leader communication approaches and patient safety: An integrated model.

PubMed

Mattson, Malin; Hellgren, Johnny; Göransson, Sara

2015-06-01

Leader communication is known to influence a number of employee behaviors. When it comes to the relationship between leader communication and safety, the evidence is more scarce and ambiguous. The aim of the present study is to investigate whether and in what way leader communication relates to safety outcomes. The study examines two leader communication approaches: leader safety priority communication and feedback to subordinates. These approaches were assumed to affect safety outcomes via different employee behaviors. Questionnaire data, collected from 221 employees at two hospital wards, were analyzed using structural equation modeling. The two examined communication approaches were both positively related to safety outcomes, although leader safety priority communication was mediated by employee compliance and feedback communication by organizational citizenship behaviors. The findings suggest that leader communication plays a vital role in improving organizational and patient safety and that different communication approaches seem to positively affect different but equally essential employee safety behaviors. The results highlights the necessity for leaders to engage in one-way communication of safety values as well as in more relational feedback communication with their subordinates in order to enhance patient safety. Copyright © 2015 Elsevier Ltd. and National Safety Council. Published by Elsevier Ltd. All rights reserved.

Visual feedback for retuning to just intonation intervals

NASA Astrophysics Data System (ADS)

Ayers, R. Dean; Nordquist, Peter R.; Corn, Justin S.

2005-04-01

Musicians become used to equal temperament pitch intervals due to their widespread use in tuning pianos and other fixed-pitch instruments. For unaccompanied singing and some other performance situations, a more harmonious blending of sounds can be achieved by shifting to just intonation intervals. Lissajous figures provide immediate and striking visual feedback that emphasizes the frequency ratios and pitch intervals found among the first few members of a single harmonic series. Spirograph patterns (hypotrochoids) are also especially simple for ratios of small whole numbers, and their use for providing feedback to singers has been suggested previously [G. W. Barton, Jr., Am. J. Phys. 44(6), 593-594 (1976)]. A hybrid mixture of these methods for comparing two frequencies generates what appears to be a three dimensional Lissajous figure-a cylindrical wire mesh that rotates about its tilted vertical axis, with zero tilt yielding the familiar Lissajous figure. Sine wave inputs work best, but the sounds of flute, recorder, whistling, and a sung ``oo'' are good enough approximations to work well. This initial study compares the three modes of presentation in terms of the ease with which a singer can obtain a desired pattern and recognize its shape.

Effects of Fe2O3 addition on the nitridation of silicon powder

NASA Technical Reports Server (NTRS)

Hasegawa, Y.; Inomata, Y.; Kijima, K.; Matsuyama, T.

1977-01-01

The reaction of silicon powder and nitrogen was studied in the range of 1300-1400 C. When an addition of Fe2O3 was more than 0.8wt%, the reaction was linear and compared to samples with no Fe2O3, the reaction velocity increased 5 to 10 times. The reactions were mediated by the process of peeling and cracking in a thin layer of Si2N4 formed on the silicon particles or on the surface of the Fe-Si melts. As the addition of Fe2O3 increased, the reaction activation energy for highly pure samples decreased. Fe2O3 which exceeded the Si3N4 solubility limits was finally converted to d-Fe.

Toward a coherent model for the melting behavior of the deep Earth's mantle

NASA Astrophysics Data System (ADS)

Andrault, D.; Bolfan-Casanova, N.; Bouhifd, M. A.; Boujibar, A.; Garbarino, G.; Manthilake, G.; Mezouar, M.; Monteux, J.; Parisiades, P.; Pesce, G.

2017-04-01

Knowledge of melting properties is critical to predict the nature and the fate of melts produced in the deep mantle. Early in the Earth's history, melting properties controlled the magma ocean crystallization, which potentially induced chemical segregation in distinct reservoirs. Today, partial melting most probably occurs in the lowermost mantle as well as at mid upper-mantle depths, which control important aspects of mantle dynamics, including some types of volcanism. Unfortunately, despite major experimental and theoretical efforts, major controversies remain about several aspects of mantle melting. For example, the liquidus of the mantle was reported (for peridotitic or chondritic-type composition) with a temperature difference of ∼1000 K at high mantle depths. Also, the Fe partitioning coefficient (DFeBg/melt) between bridgmanite (Bg, the major lower mantle mineral) and a melt was reported between ∼0.1 and ∼0.5, for a mantle depth of ∼2000 km. Until now, these uncertainties had prevented the construction of a coherent picture of the melting behavior of the deep mantle. In this article, we perform a critical review of previous works and develop a coherent, semi-quantitative, model. We first address the melting curve of Bg with the help of original experimental measurements, which yields a constraint on the volume change upon melting (ΔVm). Secondly, we apply a basic thermodynamical approach to discuss the melting behavior of mineralogical assemblages made of fractions of Bg, CaSiO3-perovskite and (Mg,Fe)O-ferropericlase. Our analysis yields quantitative constraints on the SiO2-content in the pseudo-eutectic melt and the degree of partial melting (F) as a function of pressure, temperature and mantle composition; For examples, we find that F could be more than 40% at the solidus temperature, except if the presence of volatile elements induces incipient melting. We then discuss the melt buoyancy in a partial molten lower mantle as a function of pressure, F and DFeBg/melt. In the lower mantle, density inversions (i.e. sinking melts) appear to be restricted to low F values and highest mantle pressures. The coherent melting model has direct geophysical implications: (i) in the early Earth, the magma ocean crystallization could not occur for a core temperature higher than ∼5400 K at the core-mantle boundary (CMB). This temperature corresponds to the melting of pure Bg at 135 GPa. For a mantle composition more realistic than pure Bg, the right CMB temperature for magma ocean crystallization could have been as low as ∼4400 K. (ii) There are converging arguments for the formation of a relatively homogeneous mantle after magma ocean crystallization. In particular, we predict the bulk crystallization of a relatively large mantle fraction, when the temperature becomes lower than the pseudo-eutectic temperature. Some chemical segregation could still be possible as a result of some Bg segregation in the lowermost mantle during the first stage of the magma ocean crystallization, and due to a much later descent of very low F, Fe-enriched, melts toward the CMB. (iii) The descent of such melts could still take place today. There formation should to be related to incipient mantle melting due to the presence of volatile elements. Even though, these melts can only be denser than the mantle (at high mantle depths) if the controversial value of DFeBg/melt is indeed as low as suggested by some experimental studies. This type of melts could contribute to produce ultra-low seismic velocity anomalies in the lowermost mantle.

Effect of impinging plate geometry on the self-excitation of subsonic impinging jets

NASA Astrophysics Data System (ADS)

Vinoth, B. R.; Rathakrishnan, E.

2011-11-01

In the generation of discrete tones by subsonic impinging jets, there exists a difference of opinion as how the feedback is achieved, i.e., the path of the feedback acoustic waves is whether inside the jet or outside the jet? The only available model (Tam and Ahuja model) for the prediction of an average subsonic jet impingement tone frequency assumes that the upstream part of the feedback loop is closed by an upstream propagating neutral wave of the jet. But, there is no information about the plate geometry in the model. The present study aims at understanding the effect of the plate geometry (size and co-axial hole in the plate) on the self-excitation process of subsonic impinging jets and the path of the acoustic feedback to the nozzle exit. The present results show that there is no effect of plate diameter on the frequency of the self-excitation. A new type of tones is generated for plates with co-axial hole (hole diameter is equal to nozzle exit diameter) for Mach numbers 0.9 and 0.95, in addition to the axisymmetric and helical mode tones observed for plates without co-axial hole. The stability results show that the Strouhal number of the least dispersive upstream propagating neutral waves match with the average Strouhal number of the new tones observed in the present experiments. The present study extends the validity of the model of Tam and Ahuja to a plate with co-axial hole (annular plate) and by doing so, we indirectly confirmed that the major acoustic feedback path to the nozzle exit is inside the jet.

Held in contempt: the psychological, interpersonal, and performance consequences of contempt in a work context.

PubMed

Melwani, Shimul; Barsade, Sigal G

2011-09-01

Guided by a social function of emotions perspective, the authors examined a model of the psychological, interpersonal, and performance consequences of contempt in a series of 3 experiments that tested the outcomes of being a recipient of contempt in the work domain. In these experiments, participants engaged in a business strategy simulation with a virtual partner-a computer programmed to give contemptuous and other types of feedback. In Study 1, which examined the task performance and interpersonal outcomes of contempt, recipients of contempt had significantly better task performance but also significantly more interpersonal aggressiveness toward their virtual partners compared with recipients of failure, angry, or neutral feedback. Study 2 examined 3 psychological outcomes mediating the contempt-task performance/aggression relationship: self-esteem, returned feelings of contempt, and activation levels. Lowered levels of implicit self-esteem and greater levels of activation significantly mediated the relationship between receiving contempt and task performance, whereas the contempt-aggression relationship was mediated by lowered implicit self-esteem and increased feelings of returned contempt. Study 3 examined status as a moderator of these relationships. Low-status recipients had significantly better task performance than did equal-status recipients, who performed significantly better than did the high-status recipients of contempt. In addition, low-status recipients displayed significantly lower levels of aggression in response to contempt than did equal-status and high-status recipients. PsycINFO Database Record (c) 2011 APA, all rights reserved.

Effect of Above Real Time Training and Post Flight Feedback in Training of Novice Pilots in a PC-Based Flight Simulator

NASA Technical Reports Server (NTRS)

Khan, M. Javed; Rossi, Marcia; Heath, Bruce E.; Ali, Syed firasat; Crane, Peter; Knighten, Tremaine; Culpepper, Christi

2003-01-01

The use of Post-Flight Feedback (PFFB) and Above Real-Time Training (ARTT) while training novice pilots to perform a coordinated level turn on a PC-based flight simulator was investigated. One group trained at 1.5 ARTT followed by an equal number of flights at 2.0 ARTT; the second group experienced Real Time Training (RTT). The total number of flights for both groups was equal. Each group was further subdivided into two groups one of which was provided PFFB while the other was not. Then, all participants experienced two challenging evaluation missions in real time. Performance was assessed by comparing root-mean-square error in bank-angle and altitude. Participants in the 1.512.0 ARTT No-PFFB sequence did not show improvement in performance across training sessions. An ANOVA on performance in evaluation flights found that the PFFB groups performed significantly better than those with No-PFFB. Also, the RTT groups performed significantly better than the ARTT groups. Data from two additional groups trained under a 2.011.5 ARTT PFFB and No-PFFB regimes were collected and combined with data from the previously Trainers, Real-time simulation, Personal studied groups and reanalyzed to study the computers, Man-in-the-loop simulation influence of sequence. An ANOVA on test trials found no significant effects between groups. Under training situations involving ARTT we recommend that appropriate PFFB be provided.

Specificity between Neotropical tree seedlings and their fungal mutualists leads to plant-soil feedback.

PubMed

Mangan, Scott A; Herre, Edward A; Bever, James D

2010-09-01

A growing body of evidence obtained largely from temperate grassland studies suggests that feedbacks occurring between plants and their associated soil biota are important to plant community assemblage. However, few studies have examined the importance of soil organisms in driving plant-soil feedbacks in forested systems. In a tropical forest in central Panama, we examined whether interactions between tree seedlings and their associated arbuscular mycorrhizal fungi (AMF) lead to plant-soil feedback. Specifically, do tropical seedlings modify their own AMF communities in a manner that either favors or inhibits the next cohort of conspecific seedlings (i.e., positive or negative feedback, respectively)? Seedlings of two shade-tolerant tree species (Eugenia nesiotica, Virola surinamensis) and two pioneer tree species (Luehea seemannii, Apeiba aspera) were grown in pots containing identical AMF communities composed of equal amounts of inoculum of six co-occurring AMF species. The different AMF-host combinations were all exposed to two light levels. Under low light (2% PAR), only two of the six AMF species sporulated, and we found that host identity did not influence composition of AMF spore communities. However, relative abundances of three of the four AMF species that produced spores were influenced by host identity when grown under high light (20% PAR). Furthermore, spores of one of the AMF species, Glomus geosporum, were common in soils of Luehea and Eugenia but absent in soils of Apeiba and Virola. We then conducted a reciprocal experiment to test whether AMF communities previously modified by Luehea and Apeiba differentially affected the growth of conspecific and heterospecific seedlings. Luehea seedling growth did not differ between soils containing AMF communities modified by Luehea and Apeiba. However, Apeiba seedlings were significantly larger when grown with Apeiba-modified AMF communities, as compared to Apeiba seedlings grown with Luehea-modifed AMF communities. Our experiments suggest that interactions between tropical trees and their associated AMF are species-specific and that these interactions may shape both tree and AMF communities through plant-soil feedback.

Causal uncertainty, claimed and behavioural self-handicapping.

PubMed

Thompson, Ted; Hepburn, Jonathan

2003-06-01

Causal uncertainty beliefs involve doubts about the causes of events, and arise as a consequence of non-contingent evaluative feedback: feedback that leaves the individual uncertain about the causes of his or her achievement outcomes. Individuals high in causal uncertainty are frequently unable to confidently attribute their achievement outcomes, experience anxiety in achievement situations and as a consequence are likely to engage in self-handicapping behaviour. Accordingly, we sought to establish links between trait causal uncertainty, claimed and behavioural self-handicapping. Participants were N=72 undergraduate students divided equally between high and low causally uncertain groups. We used a 2 (causal uncertainty status: high, low) x 3 (performance feedback condition: success, non-contingent success, non-contingent failure) between-subjects factorial design to examine the effects of causal uncertainty on achievement behaviour. Following performance feedback, participants completed 20 single-solution anagrams and 12 remote associate tasks serving as performance measures, and 16 unicursal tasks to assess practice effort. Participants also completed measures of claimed handicaps, state anxiety and attributions. Relative to low causally uncertain participants, high causally uncertain participants claimed more handicaps prior to performance on the anagrams and remote associates, reported higher anxiety, attributed their failure to internal, stable factors, and reduced practice effort on the unicursal tasks, evident in fewer unicursal tasks solved. These findings confirm links between trait causal uncertainty and claimed and behavioural self-handicapping, highlighting the need for educators to facilitate means by which students can achieve surety in the manner in which they attribute the causes of their achievement outcomes.

Revisiting Mn and Fe removal in humic rich estuaries

NASA Astrophysics Data System (ADS)

Oldham, Véronique E.; Miller, Megan T.; Jensen, Laramie T.; Luther, George W.

2017-07-01

Metal removal by estuarine mixing has been studied for several decades, but few studies emphasize dissolved metal speciation and organic ligand complexation. Findings from the last decade indicate that metal-humic complexation can be significant for dissolved metals including Cu(II), Al(III) and Fe(III), but little consideration is given to the precipitation of these complexes with humic material at pH < 2. Given that total soluble metal analysis involves an acidification step for sample preservation, we show that Mn and other metal concentrations may have been underestimated in estuaries, especially when humic substance concentrations are high. A competitive ligand assay of selected samples from our study site, a coastal waterway bordered by wetlands (Broadkill River, DE), showed that Mn(III)-humic complexation is significant, and that some Mn(III)-L complexes precipitate during acidification. In the oxygenated surface waters of the Broadkill River, total dissolved Mn (dMnT) was up to 100% complexed to ambient ligands as Mn(III)-L, and we present evidence for humic-type Mn(III)-L complexes. The Mn(III) complexes were kinetically stabilized against Fe(II) reduction, even when [Fe(II)] was 17 times higher than [dMnT]. Unlike typical oceanic surface waters, [Fe(II)] > [Fe(III)-L] in surface waters, which may be attributed to high rates of photoreduction of Fe(III)-L complexes. Total [Mn(III)-L] ranged from 0.22 to 8.4 μM, in excess of solid MnOx (below 0.28 μM in all samples). Filtration of samples through 0.02 μm filters indicated that all Mn(III)-L complexes pass through the filters and were not colloidal species in contrast to dissolved Fe. Incubation experiments indicated that the reductive dissolution of solid MnOx by ambient ligands may be responsible for Mn(III) formation in this system. Unlike previous studies of estuarine mixing, which demonstrated metal removal during mixing, we show significant export of dMn and dissolved Fe (dFe) in the summer and fall of 2015. Thus, we propose that estuarine removal should be considered seasonal for dMn and dFe, with export in the summer and fall and removal during the winter.

Environmental forcing of nitrogen fixation in the eastern tropical and sub-tropical North Atlantic Ocean.

PubMed

Rijkenberg, Micha J A; Langlois, Rebecca J; Mills, Matthew M; Patey, Matthew D; Hill, Polly G; Nielsdóttir, Maria C; Compton, Tanya J; Laroche, Julie; Achterberg, Eric P

2011-01-01

During the winter of 2006 we measured nifH gene abundances, dinitrogen (N(2)) fixation rates and carbon fixation rates in the eastern tropical and sub-tropical North Atlantic Ocean. The dominant diazotrophic phylotypes were filamentous cyanobacteria, which may include Trichodesmium and Katagnymene, with up to 10(6) L(-1)nifH gene copies, unicellular group A cyanobacteria with up to 10(5) L(-1)nifH gene copies and gamma A proteobacteria with up to 10(4) L(-1)nifH gene copies. N(2) fixation rates were low and ranged between 0.032-1.28 nmol N L(-1) d(-1) with a mean of 0.30 ± 0.29 nmol N L(-1) d(-1) (1σ, n = 65). CO(2)-fixation rates, representing primary production, appeared to be nitrogen limited as suggested by low dissolved inorganic nitrogen to phosphate ratios (DIN:DIP) of about 2 ± 3.2 in surface waters. Nevertheless, N(2) fixation rates contributed only 0.55 ± 0.87% (range 0.03-5.24%) of the N required for primary production. Boosted regression trees analysis (BRT) showed that the distribution of the gamma A proteobacteria and filamentous cyanobacteria nifH genes was mainly predicted by the distribution of Prochlorococcus, Synechococcus, picoeukaryotes and heterotrophic bacteria. In addition, BRT indicated that multiple a-biotic environmental variables including nutrients DIN, dissolved organic nitrogen (DON) and DIP, trace metals like dissolved aluminum (DAl), as a proxy of dust inputs, dissolved iron (DFe) and Fe-binding ligands as well as oxygen and temperature influenced N(2) fixation rates and the distribution of the dominant diazotrophic phylotypes. Our results suggest that lower predicted oxygen concentrations and higher temperatures due to climate warming may increase N(2) fixation rates. However, the balance between a decreased supply of DIP and DFe from deep waters as a result of more pronounced stratification and an enhanced supply of these nutrients with a predicted increase in deposition of Saharan dust may ultimately determine the consequences of climate warming for N(2) fixation in the North Atlantic.

Negligible contribution of reservoir dams to organic and inorganic transport in the lower Mimi River, Japan

NASA Astrophysics Data System (ADS)

Nukazawa, Kei; Kihara, Kousuke; Suzuki, Yoshihiro

2017-12-01

Rivers fulfill an essential ecological role by forming networks for material transport from upland forests to coastal areas. The way in which dams affect the organic and inorganic cycles in such systems is not well understood. Herein, we investigated the longitudinal profiles of the various components of the water chemistry across three cascade dams in Japan: the Yamasubaru Dam, Saigou Dam, and Ohuchibaru Dam, which are situated along the sediment-productive Mimi River in different flow conditions. We analyzed the following water quality components: suspended solids (SS), turbidity, total iron (TFe), dissolved iron (DFe), total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP), humic substance (HS), and major ionic components (Na+, Mg2+, Ca2+, Cl-, NO3-, and SO42-) in the downstream channels of the three dams during the low-intermediate-flow and high-flow events from 2012 to 2014. We estimated hourly loads of each component using hourly turbidity data and discharge data (i.e., L-Q model) separately, and the results are integrated to estimate the annual fluxes. The annual fluxes between the methods were compared to verify predictability of the conventional L-Q models. Annual flux of TOC, TN, DFe, and HS estimated by the turbidity displayed similar values, whereas the flux of SS, TFe, and TP tended to increase downstream of the dams. Among the dams, estimated flux proportions for TP and TFe were higher during high-flow events (74%-94%). Considering geographic conditions (e.g., absence of major tributary between the dams), the result implies that accumulated TP and TFe in the reservoirs may be flushed and transported downstream with SS over the short height dams during flood events. Assuming this process, the reservoir dams probably make only a fractional contribution to the organic and inorganic transport in the catchment studied. The percent flux errors for SS, TFe, and TP fluxes ranged from -7.2% to -97% (except for the TP flux in 2013), which highlights the risk of underestimating these components when using an L-Q model.

Random access to mobile networks with advanced error correction

NASA Technical Reports Server (NTRS)

Dippold, Michael

1990-01-01

A random access scheme for unreliable data channels is investigated in conjunction with an adaptive Hybrid-II Automatic Repeat Request (ARQ) scheme using Rate Compatible Punctured Codes (RCPC) Forward Error Correction (FEC). A simple scheme with fixed frame length and equal slot sizes is chosen and reservation is implicit by the first packet transmitted randomly in a free slot, similar to Reservation Aloha. This allows the further transmission of redundancy if the last decoding attempt failed. Results show that a high channel utilization and superior throughput can be achieved with this scheme that shows a quite low implementation complexity. For the example of an interleaved Rayleigh channel and soft decision utilization and mean delay are calculated. A utilization of 40 percent may be achieved for a frame with the number of slots being equal to half the station number under high traffic load. The effects of feedback channel errors and some countermeasures are discussed.

Peer review in design: Understanding the impact of collaboration on the review process and student perception

NASA Astrophysics Data System (ADS)

Mandala, Mahender Arjun

A cornerstone of design and design education is frequent situated feedback. With increasing class sizes, and shrinking financial and human resources, providing rich feedback to students becomes increasingly difficult. In the field of writing, web-based peer review--the process of utilizing equal status learners within a class to provide feedback to each other on their work using networked computing systems--has been shown to be a reliable and valid source of feedback in addition to improving student learning. Designers communicate in myriad ways, using the many languages of design and combining visual and descriptive information. This complex discourse of design intent makes peer reviews by design students ambiguous and often not helpful to the receivers of this feedback. Furthermore, engaging students in the review process itself is often difficult. Teams can complement individual diversity and may assist novice designers collectively resolve complex task. However, teams often incur production losses and may be impacted by individual biases. In the current work, we look at utilizing a collaborative team of reviewers, working collectively and synchronously, in generating web based peer reviews in a sophomore engineering design class. Students participated in a cross-over design, conducting peer reviews as individuals and collaborative teams in parallel sequences. Raters coded the feedback generated on the basis of their appropriateness and accuracy. Self-report surveys and passive observation of teams conducting reviews captured student opinion on the process, its value, and the contrasting experience they had conducting team and individual reviews. We found team reviews generated better quality feedback in comparison to individual reviews. Furthermore, students preferred conducting reviews in teams, finding the process 'fun' and engaging. We observed several learning benefits of using collaboration in reviewing including improved understanding of the assessment criteria, roles, expectations, and increased team reflection. These results provide insight into how to improve the review process for instructors and researchers, and forms a basis for future research work in this area. With respect to facilitating peer review process in design based classrooms, we also present recommendations for creating effective review system design and implementation in classroom supported by research and practical experience.

Assessment of Habitat Suitability Is Affected by Plant-Soil Feedback: Comparison of Field and Garden Experiment.

PubMed

Hemrová, Lucie; Knappová, Jana; Münzbergová, Zuzana

2016-01-01

Field translocation experiments (i.e., the introduction of seeds or seedlings of different species into different localities) are commonly used to study habitat associations of species, as well as factors limiting species distributions and local abundances. Species planted or sown in sites where they naturally occur are expected to perform better or equally well compared to sites at which they do not occur or are rare. This, however, contrasts with the predictions of the Janzen-Connell hypothesis and commonly reported intraspecific negative plant-soil feedback. The few previous studies indicating poorer performance of plants at sites where they naturally occur did not explore the mechanisms behind this pattern. In this study, we used field translocation experiments established using both seeds and seedlings to study the determinants of local abundance of four dominant species in grasslands. To explore the possible effects of intraspecific negative plant-soil feedback on our results, we tested the effect of local species abundance on the performance of the plants in the field experiment. In addition, we set up a garden experiment to explore the intensity of intraspecific as well as interspecific feedback between the dominants used in the experiment. In some cases, the distribution and local abundances of the species were partly driven by habitat conditions at the sites, and species performed better at their own sites. However, the prevailing pattern was that the local dominants performed worse at sites where they naturally occur than at any other sites. Moreover, the success of plants in the field experiment was lower in the case of higher intraspecific abundance prior to experimental setup. In the garden feedback experiment, two of the species performed significantly worse in soils conditioned by their species than in soils conditioned by the other species. In addition, the performance of the plants was significantly correlated between the two experiments, suggesting that plant-soil feedback is a likely explanation of the patterns observed in the field. All of the results indicate that intraspecific negative plant-soil feedback, either biotic or abiotic, may be a key factor determining the performance of the plants in our field translocation experiment. The possible effects of negative feedback should thus be considered when evaluating results of translocation experiments in future studies.

Assessment of Habitat Suitability Is Affected by Plant-Soil Feedback: Comparison of Field and Garden Experiment

PubMed Central

Hemrová, Lucie; Knappová, Jana; Münzbergová, Zuzana

2016-01-01

Background Field translocation experiments (i.e., the introduction of seeds or seedlings of different species into different localities) are commonly used to study habitat associations of species, as well as factors limiting species distributions and local abundances. Species planted or sown in sites where they naturally occur are expected to perform better or equally well compared to sites at which they do not occur or are rare. This, however, contrasts with the predictions of the Janzen-Connell hypothesis and commonly reported intraspecific negative plant-soil feedback. The few previous studies indicating poorer performance of plants at sites where they naturally occur did not explore the mechanisms behind this pattern. Aims and Methods In this study, we used field translocation experiments established using both seeds and seedlings to study the determinants of local abundance of four dominant species in grasslands. To explore the possible effects of intraspecific negative plant-soil feedback on our results, we tested the effect of local species abundance on the performance of the plants in the field experiment. In addition, we set up a garden experiment to explore the intensity of intraspecific as well as interspecific feedback between the dominants used in the experiment. Key Results In some cases, the distribution and local abundances of the species were partly driven by habitat conditions at the sites, and species performed better at their own sites. However, the prevailing pattern was that the local dominants performed worse at sites where they naturally occur than at any other sites. Moreover, the success of plants in the field experiment was lower in the case of higher intraspecific abundance prior to experimental setup. In the garden feedback experiment, two of the species performed significantly worse in soils conditioned by their species than in soils conditioned by the other species. In addition, the performance of the plants was significantly correlated between the two experiments, suggesting that plant-soil feedback is a likely explanation of the patterns observed in the field. Conclusions All of the results indicate that intraspecific negative plant-soil feedback, either biotic or abiotic, may be a key factor determining the performance of the plants in our field translocation experiment. The possible effects of negative feedback should thus be considered when evaluating results of translocation experiments in future studies. PMID:27336400

Medical humanities in the undergraduate medical curriculum.

PubMed

Supe, Avinash

2012-01-01

The medical humanities have been introduced in medical curricula over the past 30 years in the western world. Having medical humanities in a medical school curriculum can nurture positive attitudes in the regular work of a clinician and contribute equally to personality development. Though substantial evidence in favour of a medical humanities curriculum may be lacking, the feedback is positive. It is recommended that medical humanities be introduced into the curriculum of every medical school with the purpose of improving the quality of healthcare, and the attitudes of medical graduates.

Suppression of work fluctuations by optimal control: An approach based on Jarzynski's equality

NASA Astrophysics Data System (ADS)

Xiao, Gaoyang; Gong, Jiangbin

2014-11-01

Understanding and manipulating work fluctuations in microscale and nanoscale systems are of both fundamental and practical interest. For example, aspects of work fluctuations will be an important factor in designing nanoscale heat engines. In this work, an optimal control approach directly exploiting Jarzynski's equality is proposed to effectively suppress the fluctuations in the work statistics, for systems (initially at thermal equilibrium) subject to a work protocol but isolated from a bath during the protocol. The control strategy is to minimize the deviations of individual values of e-β W from their ensemble average given by e-β Δ F, where W is the work, β is the inverse temperature, and Δ F is the free energy difference between two equilibrium states. It is further shown that even when the system Hamiltonian is not fully known, it is still possible to suppress work fluctuations through a feedback loop, by refining the control target function on the fly through Jarzynski's equality itself. Numerical experiments are based on linear and nonlinear parametric oscillators. Optimal control results for linear parametric oscillators are also benchmarked with early results based on shortcuts to adiabaticity.

Feedback stabilization of an oscillating vertical cylinder by POD Reduced-Order Model

NASA Astrophysics Data System (ADS)

Tissot, Gilles; Cordier, Laurent; Noack, Bernd R.

2015-01-01

The objective is to demonstrate the use of reduced-order models (ROM) based on proper orthogonal decomposition (POD) to stabilize the flow over a vertically oscillating circular cylinder in the laminar regime (Reynolds number equal to 60). The 2D Navier-Stokes equations are first solved with a finite element method, in which the moving cylinder is introduced via an ALE method. Since in fluid-structure interaction, the POD algorithm cannot be applied directly, we implemented the fictitious domain method of Glowinski et al. [1] where the solid domain is treated as a fluid undergoing an additional constraint. The POD-ROM is classically obtained by projecting the Navier-Stokes equations onto the first POD modes. At this level, the cylinder displacement is enforced in the POD-ROM through the introduction of Lagrange multipliers. For determining the optimal vertical velocity of the cylinder, a linear quadratic regulator framework is employed. After linearization of the POD-ROM around the steady flow state, the optimal linear feedback gain is obtained as solution of a generalized algebraic Riccati equation. Finally, when the optimal feedback control is applied, it is shown that the flow converges rapidly to the steady state. In addition, a vanishing control is obtained proving the efficiency of the control approach.

Piloted Simulator Investigation of Techniques to Achieve Attitude Command Response with Limited Authority Servos

NASA Technical Reports Server (NTRS)

Key, David L.; Heffley, Robert K.

2002-01-01

The purpose of the study was to develop generic design principles for obtaining attitude command response in moderate to aggressive maneuvers without increasing SCAS series servo authority from the existing +/- 10%. In particular, to develop a scheme that would work on the UH-60 helicopter so that it can be considered for incorporation in future upgrades. The basic math model was a UH-60A version of GENHEL. The simulation facility was the NASA-Ames Vertical Motion Simulator (VMS). Evaluation tasks were Hover, Acceleration-Deceleration, and Sidestep, as defined in ADS-33D-PRF for Degraded Visual Environment (DVE). The DVE was adjusted to provide a Usable Cue Environment (UCE) equal to two. The basic concept investigated was the extent to which the limited attitude command authority achievable by the series servo could be supplemented by a 10%/sec trim servo. The architecture used provided angular rate feedback to only the series servo, shared the attitude feedback between the series and trim servos, and when the series servo approached saturation the attitude feedback was slowly phased out. Results show that modest use of the trim servo does improve pilot ratings, especially in and around hover. This improvement can be achieved with little degradation in response predictability during moderately aggressive maneuvers.

Adaptive electron beam shaping using a photoemission gun and spatial light modulator

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

Maxson, Jared; Lee, Hyeri; Bartnik, Adam C.

The need for precisely defined beam shapes in photoelectron sources has been well established. In this paper, we use a spatial light modulator and simple shaping algorithm to create arbitrary, detailed transverse laser shapes with high fidelity. We transmit this shaped laser to the photocathode of a high voltage dc gun. Using beam currents where space charge is negligible, and using an imaging solenoid and fluorescent viewscreen, we show that the resultant beam shape preserves these detailed features with similar fidelity. Next, instead of transmitting a shaped laser profile, we use an active feedback on the unshaped electron beam imagemore » to create equally accurate and detailed shapes. We demonstrate that this electron beam feedback has the added advantage of correcting for electron optical aberrations, yielding shapes without skew. The method may serve to provide precisely defined electron beams for low current target experiments, space-charge dominated beam commissioning, as well as for online adaptive correction of photocathode quantum efficiency degradation.« less

Using voice input and audio feedback to enhance the reality of a virtual experience

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

Miner, N.E.

1994-04-01

Virtual Reality (VR) is a rapidly emerging technology which allows participants to experience a virtual environment through stimulation of the participant`s senses. Intuitive and natural interactions with the virtual world help to create a realistic experience. Typically, a participant is immersed in a virtual environment through the use of a 3-D viewer. Realistic, computer-generated environment models and accurate tracking of a participant`s view are important factors for adding realism to a virtual experience. Stimulating a participant`s sense of sound and providing a natural form of communication for interacting with the virtual world are equally important. This paper discusses the advantagesmore » and importance of incorporating voice recognition and audio feedback capabilities into a virtual world experience. Various approaches and levels of complexity are discussed. Examples of the use of voice and sound are presented through the description of a research application developed in the VR laboratory at Sandia National Laboratories.« less

Adaptive electron beam shaping using a photoemission gun and spatial light modulator

NASA Astrophysics Data System (ADS)

Maxson, Jared; Lee, Hyeri; Bartnik, Adam C.; Kiefer, Jacob; Bazarov, Ivan

2015-02-01

The need for precisely defined beam shapes in photoelectron sources has been well established. In this paper, we use a spatial light modulator and simple shaping algorithm to create arbitrary, detailed transverse laser shapes with high fidelity. We transmit this shaped laser to the photocathode of a high voltage dc gun. Using beam currents where space charge is negligible, and using an imaging solenoid and fluorescent viewscreen, we show that the resultant beam shape preserves these detailed features with similar fidelity. Next, instead of transmitting a shaped laser profile, we use an active feedback on the unshaped electron beam image to create equally accurate and detailed shapes. We demonstrate that this electron beam feedback has the added advantage of correcting for electron optical aberrations, yielding shapes without skew. The method may serve to provide precisely defined electron beams for low current target experiments, space-charge dominated beam commissioning, as well as for online adaptive correction of photocathode quantum efficiency degradation.

Inclusive Competitive Game Play Through Balanced Sensory Feedback.

PubMed

Westin, Thomas; Söderström, David; Karlsson, Olov; Peiris, Ranil

2017-01-01

While game accessibility has improved significantly the last few years, there are still barriers for equal participation and multiplayer issues have been less researched. Game balance is here about making the game fair in a player versus player competitive game. One difficult design task is to balance the game to be fair regardless of visual or hearing capabilities, with clearly different requirements. This paper explores a tentative design method for enabling inclusive competitive game-play without individual adaptations of game rules that could spoil the game. The method involved applying a unified design method to design an unbalanced game, then modifying visual feedback as a hypothetical balanced design, and testing the game with totally 52 people with and without visual or hearing disabilities in three workshops. Game balance was evaluated based on score differences and less structured qualitative data, and a redesign of the game was made. Conclusions are a tentative method for balancing a multiplayer, competitive game without changing game rules and how the method can be applied.

Mental Health Support Service for University Students.

PubMed

Gale, Jill; Thalitaya, Madhusudan Deepak

2015-09-01

The Mental Health Support Service provides substantial one to one practical support for students to enable them to manage their mental health and study to provide coordinated support and ensure compliance with the Equality Act 2010. The service consists of a full time Mental Health Advisor and a part time Support Worker and is available all year round. Supervision is received from a Consultant Psychiatrist. To liaise with students and professionals when a student is admitted to hospital/Crisis Teams. Close communication with other services such as Student Engagement, the International Office, the Chaplain and academics. Data from the Office of National Statistics between 2007 and 2011 have shown an increase in the number of student suicides since the start of the recession. Feedback highlights that students benefit from the support and value the professional and welcoming attitude of the team. The service continues to provide good quality support to those who access it. Student feedback shows that they believe the support has helped them to stay at university and complete their degree.

Adaptive electron beam shaping using a photoemission gun and spatial light modulator

DOE PAGES

Maxson, Jared; Lee, Hyeri; Bartnik, Adam C.; ...

2015-02-01

The need for precisely defined beam shapes in photoelectron sources has been well established. In this paper, we use a spatial light modulator and simple shaping algorithm to create arbitrary, detailed transverse laser shapes with high fidelity. We transmit this shaped laser to the photocathode of a high voltage dc gun. Using beam currents where space charge is negligible, and using an imaging solenoid and fluorescent viewscreen, we show that the resultant beam shape preserves these detailed features with similar fidelity. Next, instead of transmitting a shaped laser profile, we use an active feedback on the unshaped electron beam imagemore » to create equally accurate and detailed shapes. We demonstrate that this electron beam feedback has the added advantage of correcting for electron optical aberrations, yielding shapes without skew. The method may serve to provide precisely defined electron beams for low current target experiments, space-charge dominated beam commissioning, as well as for online adaptive correction of photocathode quantum efficiency degradation.« less

Decisions under distress: stress profiles influence anchoring and adjustment.

PubMed

Kassam, Karim S; Koslov, Katrina; Mendes, Wendy Berry

2009-11-01

People frequently make decisions under stress. Understanding how stress affects decision making is complicated by the fact that not all stress responses are created equal. Challenge states, for example, occur when individuals appraise a stressful situation as demanding, but believe they have the personal resources to cope, and are characterized by efficient cardiovascular reactivity and approach motivation. Threat states, in contrast, occur when situational demands are perceived to outweigh resources and are characterized by less efficient cardiovascular reactivity and withdrawal motivation. We randomly assigned participants to social-feedback conditions (i.e., positive or negative feedback) designed to engender challenge or threat, or a no-stress condition. Participants then completed an anchoring-and-adjustment questionnaire. Those assigned to the challenge condition adjusted more from self-generated anchors than those assigned to the threat condition. Cardiovascular responses mediated the relationship between condition and adjustment. This study demonstrates the importance of considering profiles of cardiovascular reactivity when examining the influence of stress on decision making.

Decisions Under Distress Stress Profiles Influence Anchoring and Adjustment

PubMed Central

Kassam, Karim S.; Koslov, Katrina; Mendes, Wendy Berry

2009-01-01

People frequently make decisions under stress. Understanding how stress affects decision making is complicated by the fact that not all stress responses are created equal. Challenge states, for example, occur when individuals appraise a stressful situation as demanding, but believe they have the personal resources to cope, and are characterized by efficient cardiovascular reactivity and approach motivation. Threat states, in contrast, occur when situational demands are perceived to outweigh resources and are characterized by less efficient cardiovascular reactivity and withdrawal motivation. We randomly assigned participants to social-feedback conditions (i.e., positive or negative feedback) designed to engender challenge or threat, or a no-stress condition. Participants then completed an anchoring-and-adjustment questionnaire. Those assigned to the challenge condition adjusted more from self-generated anchors than those assigned to the threat condition. Cardiovascular responses mediated the relationship between condition and adjustment. This study demonstrates the importance of considering profiles of cardiovascular reactivity when examining the influence of stress on decision making. PMID:19843261

Frequency adaptation in controlled stochastic resonance utilizing delayed feedback method: two-pole approximation for response function.

PubMed

Tutu, Hiroki

2011-06-01

Stochastic resonance (SR) enhanced by time-delayed feedback control is studied. The system in the absence of control is described by a Langevin equation for a bistable system, and possesses a usual SR response. The control with the feedback loop, the delay time of which equals to one-half of the period (2π/Ω) of the input signal, gives rise to a noise-induced oscillatory switching cycle between two states in the output time series, while its average frequency is just smaller than Ω in a small noise regime. As the noise intensity D approaches an appropriate level, the noise constructively works to adapt the frequency of the switching cycle to Ω, and this changes the dynamics into a state wherein the phase of the output signal is entrained to that of the input signal from its phase slipped state. The behavior is characterized by power loss of the external signal or response function. This paper deals with the response function based on a dichotomic model. A method of delay-coordinate series expansion, which reduces a non-Markovian transition probability flux to a series of memory fluxes on a discrete delay-coordinate system, is proposed. Its primitive implementation suggests that the method can be a potential tool for a systematic analysis of SR phenomenon with delayed feedback loop. We show that a D-dependent behavior of poles of a finite Laplace transform of the response function qualitatively characterizes the structure of the power loss, and we also show analytical results for the correlation function and the power spectral density.

Chest compression rate feedback based on transthoracic impedance.

PubMed

González-Otero, Digna M; Ruiz de Gauna, Sofía; Ruiz, Jesus; Daya, Mohamud R; Wik, Lars; Russell, James K; Kramer-Johansen, Jo; Eftestøl, Trygve; Alonso, Erik; Ayala, Unai

2015-08-01

Quality of cardiopulmonary resuscitation (CPR) is an important determinant of survival from cardiac arrest. The use of feedback devices is encouraged by current resuscitation guidelines as it helps rescuers to improve quality of CPR performance. To determine the feasibility of a generic algorithm for feedback related to chest compression (CC) rate using the transthoracic impedance (TTI) signal recorded through the defibrillation pads. We analysed 180 episodes collected equally from three different emergency services, each one using a unique defibrillator model. The new algorithm computed the CC-rate every 2s by analysing the TTI signal in the frequency domain. The obtained CC-rate values were compared with the gold standard, computed using the compression force or the ECG and TTI signals when the force was not recorded. The accuracy of the CC-rate, the proportion of alarms of inadequate CC-rate, chest compression fraction (CCF) and the mean CC-rate per episode were calculated. Intervals with CCs were detected with a mean sensitivity and a mean positive predictive value per episode of 96.3% and 97.0%, respectively. Estimated CC-rate had an error below 10% in 95.8% of the time. Mean percentage of accurate alarms per episode was 98.2%. No statistical differences were found between the gold standard and the estimated values for any of the computed metrics. We developed an accurate algorithm to calculate and provide feedback on CC-rate using the TTI signal. This could be integrated into automated external defibrillators and help improve the quality of CPR in basic-life-support settings. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Learning processes underlying avoidance of negative outcomes.

PubMed

Andreatta, Marta; Michelmann, Sebastian; Pauli, Paul; Hewig, Johannes

2017-04-01

Successful avoidance of a threatening event may negatively reinforce the behavior due to activation of brain structures involved in reward processing. Here, we further investigated the learning-related properties of avoidance using feedback-related negativity (FRN). The FRN is modulated by violations of an intended outcome (prediction error, PE), that is, the bigger the difference between intended and actual outcome, the larger the FRN amplitude is. Twenty-eight participants underwent an operant conditioning paradigm, in which a behavior (button press) allowed them to avoid a painful electric shock. During two learning blocks, participants could avoid an electric shock in 80% of the trials by pressing one button (avoidance button), or by not pressing another button (punishment button). After learning, participants underwent two test blocks, which were identical to the learning ones except that no shocks were delivered. Participants pressed the avoidance button more often than the punishment button. Importantly, response frequency increased throughout the learning blocks but it did not decrease during the test blocks, indicating impaired extinction and/or habit formation. In line with a PE account, FRN amplitude to negative feedback after correct responses (i.e., unexpected punishment) was significantly larger than to positive feedback (i.e., expected omission of punishment), and it increased throughout the blocks. Highly anxious individuals showed equal FRN amplitudes to negative and positive feedback, suggesting impaired discrimination. These results confirm the role of negative reinforcement in motivating behavior and learning, and reveal important differences between high and low anxious individuals in the processing of prediction errors. © 2017 Society for Psychophysiological Research.

The Cosmic History of Hot Gas Cooling and Radio AGN Activity in Massive Early-Type Galaxies

NASA Technical Reports Server (NTRS)

Danielson, A. L. R.; Lehmer, B. D.; Alexander, D. M.; Brandt, W. M.; Luo, B.; Miller, N.; Xue, Y. Q.; Stott, J. P.

2012-01-01

We study the X-ray properties of 393 optically selected early-type galaxies (ETGs) over the redshift range of z approx equals 0.0-1.2 in the Chandra Deep Fields. To measure the average X-ray properties of the ETG population, we use X-ray stacking analyses with a subset of 158 passive ETGs (148 of which were individually undetected in X-ray). This ETG subset was constructed to span the redshift ranges of z = 0.1-1.2 in the approx equals 4 Ms CDF-S and approx equals 2 Ms CDF-N and z = 0.1-0.6 in the approx equals 250 ks E-CDF-S where the contribution from individually undetected AGNs is expected to be negligible in our stacking. We find that 55 of the ETGs are detected individually in the X-rays, and 12 of these galaxies have properties consistent with being passive hot-gas dominated systems (i.e., systems not dominated by an X-ray bright Active Galactic Nucleus; AGN). On the basis of our analyses, we find little evolution in the mean 0.5-2 keY to B-band luminosity ratio (L(sub x) /L(sub Beta) varies as [1 +z]) since z approx equals 1.2, implying that some heating mechanism prevents the gas from cooling in these systems. We consider that feedback from radio-mode AGN activity could be responsible for heating the gas. We select radio AGNs in the ETG population using their far-infrared/radio flux ratio. Our radio observations allow us to constrain the duty cycle history of radio AGN activity in our ETG sample. We estimate that if scaling relations between radio and mechanical power hold out to z approx equals 1.2 for the ETG population being studied here, the average mechanical power from AGN activity is a factor of approx equals1.4 -- 2.6 times larger than the average radiative cooling power from hot gas over the redshift range z approx equals 0-1.2. The excess of inferred AGN mechanical power from these ETGs is consistent with that found in the local Universe for similar types of galaxies.

How Do Learning Outcomes, Assessments and Student Engagement in a Fully Online Geoscience Laboratory Compare to Those Of The Original Hands-on Exercise?

NASA Astrophysics Data System (ADS)

Jones, F. M.

2015-12-01

In a third year geoscience elective for BSc majors, we adapted several active f2f learning strategies for an equivalent fully online version of the course. In particular, we converted a hands-on laboratory including analysis and interpretation of hand-specimens, sketching results and peer-to-peer discussion of scientific implications. This study compares learning outcomes in both formats and describes resources that make engaging, effective and efficient learning experiences for large classes in an asynchronous online environment. Our two hypotheses are: 1) a hands-on geology lab exercise can be converted for efficient fully online use without sacrificing feedback and assessment opportunities; 2) students find either the f2f or DE versions equally effective and enjoyable as learning experiences. Key components are an authentic context, interactive resources including sketching, strategies that enable efficient assessment and feedback on solo and group work, and asynchronous yet productive interaction with peers. Students in the f2f class handle real rock and fossil specimens, work with peers in the lab and classroom, and deliver most results including annotated figures on paper. DE students complete identical tasks using interactive high resolution figures and videos of specimens. Solo work is first delivered for automated assessment and feedback, then students engage asynchronously in small groups to improve results and discuss implications. Chronostratigraphy and other interpretations are sketched on prepared template images using a simple open-source sketching app that ensures equal access and consistent results that are efficient to assess by peers and instructors. Learning outcomes based on subsequent quizzes, sketches, and lab results (paper for f2f students and automated data entry for DE students), show that f2f and online students demonstrate knowledge and scientific interpretations of comparable quality. Effective engagement and group work are demonstrated for f2f students using video and survey data, and for DE students using learning management system tracking data and similar survey data. Finally, these initiatives are shown to be scalable to classes of many students by comparing the time required for instructors to run and grade the lab in both settings.

Feedback Augmented Sub-Ranging (FASR) Quantizer

NASA Technical Reports Server (NTRS)

Guilligan, Gerard

2012-01-01

This innovation is intended to reduce the size, power, and complexity of pipeline analog-to-digital converters (ADCs) that require high resolution and speed along with low power. Digitizers are important components in any application where analog signals (such as light, sound, temperature, etc.) need to be digitally processed. The innovation implements amplification of a sampled residual voltage in a switched capacitor amplifier stage that does not depend on charge redistribution. The result is less sensitive to capacitor mismatches that cause gain errors, which are the main limitation of such amplifiers in pipeline ADCs. The residual errors due to mismatch are reduced by at least a factor of 16, which is equivalent to at least 4 bits of improvement. The settling time is also faster because of a higher feedback factor. In traditional switched capacitor residue amplifiers, closed-loop amplification of a sampled and held residue signal is achieved by redistributing sampled charge onto a feedback capacitor around a high-gain transconductance amplifier. The residual charge that was sampled during the acquisition or sampling phase is stored on two or more capacitors, often equal in value or integral multiples of each other. During the hold or amplification phase, all of the charge is redistributed onto one capacitor in the feedback loop of the amplifier to produce an amplified voltage. The key error source is the non-ideal ratios of feedback and input capacitors caused by manufacturing tolerances, called mismatches. The mismatches cause non-ideal closed-loop gain, leading to higher differential non-linearity. Traditional solutions to the mismatch errors are to use larger capacitor values (than dictated by thermal noise requirements) and/or complex calibration schemes, both of which increase the die size and power dissipation. The key features of this innovation are (1) the elimination of the need for charge redistribution to achieve an accurate closed-loop gain of two, (2) a higher feedback factor in the amplifier stage giving a higher closed-loop bandwidth compared to the prior art, and (3) reduced requirement for calibration. The accuracy of the new amplifier is mainly limited by the sampling networks parasitic capacitances, which should be minimized in relation to the sampling capacitors.

Chemical Composition and Inhibitory Effect of Lentinula edodes Ethanolic Extract on Experimentally Induced Atopic Dermatitis in Vitro and in Vivo.

PubMed

Choi, Eun-Ju; Park, Zee-Yong; Kim, Eun-Kyung

2016-07-29

The ethanolic extract of Lentinula edodes was partially analyzed and then characterized for its efficacy in treating atopic dermatitis. Polyphenols were determined to be the major antioxidant component in the extract (6.12 mg/g), followed by flavonoids (1.76 mg/g), β-carotene (28.75 μg/g), and lycopene (5.25 μg/g). An atopic dermatitis (AD) model was established and epidermal and dermal ear thickness, mast cell infiltration, and serum immunoglobulin levels were measured after oral administration of the L. edodes extract for 4 weeks. L. edodes extract decreased Dermatophagoides farinae extract (DFE) and 4-dinitrochlorobenzene (DNCB)-induced expression of several inflammatory cytokines in the ears, cervical lymph nodes, and splenocytes. Consequently, L. edodes extract may have therapeutic potential in the treatment of AD attributable to its immunomodulatory effects.

Diverse stoichiometry of dissolved trace metals in the Indian Ocean

PubMed Central

Thi Dieu Vu, Huong; Sohrin, Yoshiki

2013-01-01

Trace metals in seawater are essential to organisms and important as tracers of various processes in the ocean. However, we do not have a good understanding of the global distribution and cycling of trace metals, especially in the Indian Ocean. Here we report the first simultaneous, full-depth, and basin-scale section-distribution of dissolved (D) Al, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb in the Indian Ocean. Our data reveal widespread co-limitation for phytoplankton production by DFe and occurrence of redox-related processes. The stoichiometry of the DM/phosphorus ratio agrees within a factor of 5 between deep waters in the Indian and Pacific, whereas it shows variability up to a factor of 300 among water masses within the Indian Ocean. This indicates that a consistent mechanism controls the stoichiometry in the deep waters, which are significantly depleted in Mn, Fe, and Co compared to requirements for phytoplankton.

Re-examining the effects of noncontingent success on self-handicapping behaviour.

PubMed

Thompson, Ted

2004-06-01

Self-handicapping refers to the practice on the part of certain individuals to handicap their performance when poor performance is likely to reveal low ability. Noncontingent success (feedback that is inflated relative to performance) is more likely to promote self-handicapping behaviour than noncontingent failure (failure feedback based on false or misleading information). However, the reasons for the differing effects of these forms of performance feedback on self-handicapping behaviour remain obscure. The present study sought an explanation for the differing effects of these forms of performance feedback, testing the assumption that students high in self-handicapping behaviour would react more negatively following noncontingent success, reporting more unstable and external attributions, higher anxiety, and a greater propensity to claim handicaps than those low in self-handicapping behaviour. No differences were expected on any of these measures for high relative to low self-handicappers following either noncontingent failure or success. Participants were 72 undergraduate students, divided equally between high and low self-handicapping groups. High and low self-handicappers were assigned to one of three performance feedback conditions: noncontingent failure, success and noncontingent success. High and low self-handicappers were then given an opportunity to claim handicaps prior to completing measures of attributions and state anxiety. Subsequently, they completed 12 remote associate tasks, serving as an assessment of performance, and 16 unicursal tasks, assessing practice effort. Following noncontingent success, high self-handicappers reported greater anxiety, more unproductive attributions and claimed more handicaps than low self-handicappers. However no differences were evident for high and low self-handicappers following either noncontingent failure or success. High self-handicappers also performed poorly on the remote associates tasks and reduced practice effort on the unicursal tasks. These findings confirm the adverse effects of noncontingent success for high self-handicappers, while failing to provide evidence that noncontingent failure has any more adverse effects on high relative to low self-handicappers.

An improved contrast enhancement algorithm for infrared images based on adaptive double plateaus histogram equalization

NASA Astrophysics Data System (ADS)

Li, Shuo; Jin, Weiqi; Li, Li; Li, Yiyang

2018-05-01

Infrared thermal images can reflect the thermal-radiation distribution of a particular scene. However, the contrast of the infrared images is usually low. Hence, it is generally necessary to enhance the contrast of infrared images in advance to facilitate subsequent recognition and analysis. Based on the adaptive double plateaus histogram equalization, this paper presents an improved contrast enhancement algorithm for infrared thermal images. In the proposed algorithm, the normalized coefficient of variation of the histogram, which characterizes the level of contrast enhancement, is introduced as feedback information to adjust the upper and lower plateau thresholds. The experiments on actual infrared images show that compared to the three typical contrast-enhancement algorithms, the proposed algorithm has better scene adaptability and yields better contrast-enhancement results for infrared images with more dark areas or a higher dynamic range. Hence, it has high application value in contrast enhancement, dynamic range compression, and digital detail enhancement for infrared thermal images.

On the stabilizability of multivariable systems by minimum order compensation

NASA Technical Reports Server (NTRS)

Byrnes, C. I.; Anderson, B. D. O.

1983-01-01

In this paper, a derivation is provided of the necessary condition, mp equal to or greater than n, for stabilizability by constant gain feedback of the generic degree n, p x m system. This follows from another of the main results, which asserts that generic stabilizability is equivalent to generic solvability of a deadbeat control problem, provided mp equal to or less than n. Taken together, these conclusions make it possible to make some sharp statements concerning minimum order stabilization. The techniques are primarily drawn from decision algebra and classical algebraic geometry and have additional consequences for problems of stabilizability and pole-assignability. Among these are the decidability (by a Sturm test) of the equivalence of generic pole-assignability and generic stabilizability, the semi-algebraic nature of the minimum order, q, of a stabilizing compensator, and the nonexistence of formulae involving rational operations and extraction of square roots for pole-assigning gains when they exist, answering in the negative a question raised by Anderson, Bose, and Jury (1975).

The rotational feedback on linear-momentum balance in glacial isostatic adjustment

NASA Astrophysics Data System (ADS)

Martinec, Zdenek; Hagedoorn, Jan

2015-04-01

The influence of changes in surface ice-mass redistribution and associated viscoelastic response of the Earth, known as glacial-isostatic adjustment (GIA), on the Earth's rotational dynamics has long been known. Equally important is the effect of the changes in the rotational dynamics on the viscoelastic deformation of the Earth. This signal, known as the rotational feedback, or more precisely, the rotational feedback on the sea-level equation, has been mathematically described by the sea-level equation extended for the term that is proportional to perturbation in the centrifugal potential and the second-degree tidal Love number. The perturbation in the centrifugal force due to changes in the Earth's rotational dynamics enters not only into the sea-level equation, but also into the conservation law of linear momentum such that the internal viscoelastic force, the perturbation in the gravitational force and the perturbation in the centrifugal force are in balance. Adding the centrifugal-force perturbation to the linear-momentum balance creates an additional rotational feedback on the viscoelastic deformations of the Earth. We term this feedback mechanism as the rotational feedback on the linear-momentum balance. We extend both the time-domain method for modelling the GIA response of laterally heterogeneous earth models and the traditional Laplace-domain method for modelling the GIA-induced rotational response to surface loading by considering the rotational feedback on linear-momentum balance. The correctness of the mathematical extensions of the methods is validated numerically by comparing the polar motion response to the GIA process and the rotationally-induced degree 2 and order 1 spherical harmonic component of the surface vertical displacement and gravity field. We present the difference between the case where the rotational feedback on linear-momentum balance is considered against that where it is not. Numerical simulations show that the resulting difference in radial displacement and sea-level change between these situations since the Last Glacial Maximum reaches values of ± 25 m and ± 1.8 m, respectively. Furthermore, the surface deformation pattern is modified by up to 10% in areas of former or ongoing glaciation, but by up to 50% at the bottom of the southern Indian ocean. This also results in the movement of coastlines during the last deglaciation to differ between the two cases due to the difference in the ocean loading, which is seen for instance in the area around Hudson Bay, Canada, and along the Chinese, Australian, or Argentinian coastlines.

The rotational feedback on linear-momentum balance in glacial isostatic adjustment

NASA Astrophysics Data System (ADS)

Martinec, Zdeněk; Hagedoorn, Jan

2014-12-01

The influence of changes in surface ice-mass redistribution and associated viscoelastic response of the Earth, known as glacial isostatic adjustment (GIA), on the Earth's rotational dynamics has long been known. Equally important is the effect of the changes in the rotational dynamics on the viscoelastic deformation of the Earth. This signal, known as the rotational feedback, or more precisely, the rotational feedback on the sea level equation, has been mathematically described by the sea level equation extended for the term that is proportional to perturbation in the centrifugal potential and the second-degree tidal Love number. The perturbation in the centrifugal force due to changes in the Earth's rotational dynamics enters not only into the sea level equation, but also into the conservation law of linear momentum such that the internal viscoelastic force, the perturbation in the gravitational force and the perturbation in the centrifugal force are in balance. Adding the centrifugal-force perturbation to the linear-momentum balance creates an additional rotational feedback on the viscoelastic deformations of the Earth. We term this feedback mechanism, which is studied in this paper, as the rotational feedback on the linear-momentum balance. We extend both the time-domain method for modelling the GIA response of laterally heterogeneous earth models developed by Martinec and the traditional Laplace-domain method for modelling the GIA-induced rotational response to surface loading by considering the rotational feedback on linear-momentum balance. The correctness of the mathematical extensions of the methods is validated numerically by comparing the polar-motion response to the GIA process and the rotationally induced degree 2 and order 1 spherical harmonic component of the surface vertical displacement and gravity field. We present the difference between the case where the rotational feedback on linear-momentum balance is considered against that where it is not. Numerical simulations show that the resulting difference in radial displacement and sea level change between these situations since the Last Glacial Maximum reaches values of ±25 and ±1.8 m, respectively. Furthermore, the surface deformation pattern is modified by up to 10 per cent in areas of former or ongoing glaciation, but by up to 50 per cent at the bottom of the southern Indian ocean. This also results in the movement of coastlines during the last deglaciation to differ between the two cases due to the difference in the ocean loading, which is seen for instance in the area around Hudson Bay, Canada and along the Chinese, Australian or Argentinian coastlines.

Pursuit tracking and higher levels of skill development in the human pilot

NASA Technical Reports Server (NTRS)

Hess, R. A.

1981-01-01

A model of the human pilot is offered for pursuit tracking tasks; the model encompasses an existing model for compensatory tracking. The central hypothesis in the development of this model states that those primary structural elements in the compensatory model responsible for the pilot's equalization capabilities remain intact in the pursuit model. In this latter case, effective low-frequency inversion of the controlled-element dynamics occurs by feeding-forward derived input rate through the equalization dynamics, with low-frequency phase droop minimized. The sharp reduction in low-frequency phase lag beyond that associated with the disappearance of phase droop is seen to accompany relatively low-gain feedback of vehicle output. The results of some recent motion cue research are discussed and interpreted in terms of the compensatory-pursuit display dichotomy. Tracking with input preview is discussed in a qualitative way. In terms of the model, preview is shown to demand no fundamental changes in structure or equalization and to allow the pilot to eliminate the effective time delays that accrue in the inversion of the controlled-element dynamics. Precognitive behavior is discussed, and a model that encompasses all the levels of skill development outlined in the successive organizations of perception theory is finally proposed.

Successful Therapist-Parent Coaching: How In Vivo Feedback Relates to Parent Engagement in Parent-Child Interaction Therapy.

PubMed

Barnett, Miya L; Niec, Larissa N; Peer, Samuel O; Jent, Jason F; Weinstein, Allison; Gisbert, Patricia; Simpson, Gregory

2017-01-01

Although behavioral parent training is considered efficacious treatment for childhood conduct problems, not all families benefit equally from treatment. Some parents take longer to change their behaviors and others ultimately drop out. Understanding how therapist behaviors impact parental engagement is necessary to improve treatment utilization. This study investigated how different techniques of therapist in vivo feedback (i.e., coaching) influenced parent attrition and skill acquisition in parent-child interaction therapy (PCIT). Participants included 51 parent-child dyads who participated in PCIT. Children (age: M = 5.03, SD = 1.65) were predominately minorities (63% White Hispanic, 16% African American or Black). Eight families discontinued treatment prematurely. Therapist coaching techniques during the first session of treatment were coded using the Therapist-Parent Interaction Coding System, and parent behaviors were coded with the Dyadic Parent-Child Interaction Coding System, Third Edition. Parents who received more responsive coaching acquired child-centered parenting skills more quickly. Therapists used fewer responsive techniques and more drills with families who dropped out of treatment. A composite of therapist behaviors accurately predicted treatment completion for 86% of families. Although group membership was correctly classified for the treatment completers, only 1 dropout was accurately predicted. Findings suggest that therapist in vivo feedback techniques may impact parents' success in PCIT and that responsive coaching may be particularly relevant.

A Novel Artificial Bee Colony Algorithm Based on Internal-Feedback Strategy for Image Template Matching

PubMed Central

Gong, Li-Gang

2014-01-01

Image template matching refers to the technique of locating a given reference image over a source image such that they are the most similar. It is a fundamental mission in the field of visual target recognition. In general, there are two critical aspects of a template matching scheme. One is similarity measurement and the other is best-match location search. In this work, we choose the well-known normalized cross correlation model as a similarity criterion. The searching procedure for the best-match location is carried out through an internal-feedback artificial bee colony (IF-ABC) algorithm. IF-ABC algorithm is highlighted by its effort to fight against premature convergence. This purpose is achieved through discarding the conventional roulette selection procedure in the ABC algorithm so as to provide each employed bee an equal chance to be followed by the onlooker bees in the local search phase. Besides that, we also suggest efficiently utilizing the internal convergence states as feedback guidance for searching intensity in the subsequent cycles of iteration. We have investigated four ideal template matching cases as well as four actual cases using different searching algorithms. Our simulation results show that the IF-ABC algorithm is more effective and robust for this template matching mission than the conventional ABC and two state-of-the-art modified ABC algorithms do. PMID:24892107

Adolescent-specific patterns of behavior and neural activity during social reinforcement learning

PubMed Central

Jones, Rebecca M.; Somerville, Leah H.; Li, Jian; Ruberry, Erika J.; Powers, Alisa; Mehta, Natasha; Dyke, Jonathan; Casey, BJ

2014-01-01

Humans are sophisticated social beings. Social cues from others are exceptionally salient, particularly during adolescence. Understanding how adolescents interpret and learn from variable social signals can provide insight into the observed shift in social sensitivity during this period. The current study tested 120 participants between the ages of 8 and 25 years on a social reinforcement learning task where the probability of receiving positive social feedback was parametrically manipulated. Seventy-eight of these participants completed the task during fMRI scanning. Modeling trial-by-trial learning, children and adults showed higher positive learning rates than adolescents, suggesting that adolescents demonstrated less differentiation in their reaction times for peers who provided more positive feedback. Forming expectations about receiving positive social reinforcement correlated with neural activity within the medial prefrontal cortex and ventral striatum across age. Adolescents, unlike children and adults, showed greater insular activity during positive prediction error learning and increased activity in the supplementary motor cortex and the putamen when receiving positive social feedback regardless of the expected outcome, suggesting that peer approval may motivate adolescents towards action. While different amounts of positive social reinforcement enhanced learning in children and adults, all positive social reinforcement equally motivated adolescents. Together, these findings indicate that sensitivity to peer approval during adolescence goes beyond simple reinforcement theory accounts and suggests possible explanations for how peers may motivate adolescent behavior. PMID:24550063

Adolescent-specific patterns of behavior and neural activity during social reinforcement learning.

PubMed

Jones, Rebecca M; Somerville, Leah H; Li, Jian; Ruberry, Erika J; Powers, Alisa; Mehta, Natasha; Dyke, Jonathan; Casey, B J

2014-06-01

Humans are sophisticated social beings. Social cues from others are exceptionally salient, particularly during adolescence. Understanding how adolescents interpret and learn from variable social signals can provide insight into the observed shift in social sensitivity during this period. The present study tested 120 participants between the ages of 8 and 25 years on a social reinforcement learning task where the probability of receiving positive social feedback was parametrically manipulated. Seventy-eight of these participants completed the task during fMRI scanning. Modeling trial-by-trial learning, children and adults showed higher positive learning rates than did adolescents, suggesting that adolescents demonstrated less differentiation in their reaction times for peers who provided more positive feedback. Forming expectations about receiving positive social reinforcement correlated with neural activity within the medial prefrontal cortex and ventral striatum across age. Adolescents, unlike children and adults, showed greater insular activity during positive prediction error learning and increased activity in the supplementary motor cortex and the putamen when receiving positive social feedback regardless of the expected outcome, suggesting that peer approval may motivate adolescents toward action. While different amounts of positive social reinforcement enhanced learning in children and adults, all positive social reinforcement equally motivated adolescents. Together, these findings indicate that sensitivity to peer approval during adolescence goes beyond simple reinforcement theory accounts and suggest possible explanations for how peers may motivate adolescent behavior.

Effects of acidic amino acid antagonists upon the spectral properties of carp horizontal cells: circuitry of the outer retina.

PubMed

Mangel, S C; Ariel, M; Dowling, J E

1985-11-01

The acidic amino acid receptor antagonists, alpha-methylglutamate and alpha-aminoadipate, were applied to the carp retina to study their effects upon the spectral properties of horizontal cells and to elucidate the synaptic connections between horizontal cells and cones. Application of these antagonists strongly hyperpolarized the L-type cone horizontal cells and reduced the responses of these horizontal cells to red light more than to blue light. Application of Co2+ ions to the retina, a procedure which decreases transmitter release, also hyperpolarized the L-type cone horizontal cells but reduced the response of these horizontal cells to red and blue lights equally. These results suggest that red- or long wavelength-sensitive cones release a different transmitter onto L-type cone horizontal cells than do short wavelength-sensitive cones. Application of the acidic amino acid antagonists also revealed details of the feedback pathway from L-type cone horizontal cells to cones. Previous studies have shown that feedback varies directly with stimulus size and that the effects of feedback on the responses of cones are observed as a transient waveform at response onset (a large, hyperpolarizing potential that is quickly followed by a smaller plateau potential). Application of the acidic amino acid antagonists at a dose which partially hyperpolarized the horizontal cells selectively enhanced the response of the cells to blue lights, when full field, and not spot, stimuli were used. The antagonists also eliminated the transient at response onset. These findings are consistent with the presence of a feedback pathway from L-type cone horizontal cells to short wavelength cones but not to long (red-sensitive) cones.

A VERY DEEP CHANDRA OBSERVATION OF THE GALAXY GROUP NGC 5813: AGN SHOCKS, FEEDBACK, AND OUTBURST HISTORY

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

Randall, S. W.; Nulsen, P. E. J.; Jones, C.

2015-06-01

We present results from a very deep (650 ks) Chandra X-ray observation of the galaxy group NGC 5813, the deepest Chandra observation of a galaxy group to date. This system uniquely shows three pairs of collinear cavities, with each pair associated with an unambiguous active galactic nucleus (AGN) outburst shock front. The implied mean kinetic power is roughly the same for each outburst, demonstrating that the average AGN kinetic luminosity can remain stable over long timescales (∼50 Myr). The two older outbursts have larger, roughly equal total energies as compared with the youngest outburst, implying that the youngest outburst ismore » ongoing. We find that the gas radiative cooling rate and mean shock heating rate are well balanced at each shock front, suggesting that shock heating alone is sufficient to offset cooling and establish AGN/intracluster medium (ICM) feedback within at least the central 30 kpc. This heating takes place roughly isotropically and most strongly at small radii, as is required for feedback to operate. We suggest that shock heating may play a significant role in AGN feedback at smaller radii in other systems, where weak shocks are more difficult to detect. We find non-zero shock front widths that are too large to be explained by particle diffusion. Instead, all measured widths are consistent with shock broadening due to propagation through a turbulent ICM with a mean turbulent speed of ∼70 km s{sup −1}. Finally, we place lower limits on the temperature of any volume-filling thermal gas within the cavities that would balance the internal cavity pressure with the external ICM.« less

Feasibility and effects of home-based smartphone-delivered automated feedback training for gait in people with Parkinson's disease: A pilot randomized controlled trial.

PubMed

Ginis, Pieter; Nieuwboer, Alice; Dorfman, Moran; Ferrari, Alberto; Gazit, Eran; Canning, Colleen G; Rocchi, Laura; Chiari, Lorenzo; Hausdorff, Jeffrey M; Mirelman, Anat

2016-01-01

Inertial measurement units combined with a smartphone application (CuPiD-system) were developed to provide people with Parkinson's disease (PD) real-time feedback on gait performance. This study investigated the CuPiD-system's feasibility and effectiveness compared with conventional gait training when applied in the home environment. Forty persons with PD undertook gait training for 30 min, three times per week for six weeks. Participants were randomly assigned to i) CuPiD, in which a smartphone application offered positive and corrective feedback on gait, or ii) an active control, in which personalized gait advice was provided. Gait, balance, endurance and quality of life were assessed before and after training and at four weeks follow-up using standardized tests. Both groups improved significantly on the primary outcomes (single and dual task gait speed) at post-test and follow-up. The CuPiD group improved significantly more on balance (MiniBESTest) at post-test (from 24.8 to 26.1, SD ∼ 5) and maintained quality of life (SF-36 physical health) at follow-up whereas the control group deteriorated (from 50.4 to 48.3, SD ∼ 16). No other statistically significant differences were found between the two groups. The CuPiD system was well-tolerated and participants found the tool user-friendly. CuPiD was feasible, well-accepted and seemed to be an effective approach to promote gait training, as participants improved equally to controls. This benefit may be ascribed to the real-time feedback, stimulating corrective actions and promoting self-efficacy to achieve optimal performance. Further optimization of the system and adequately-powered studies are warranted to corroborate these findings and determine cost-effectiveness.

Detection of Remarkably Low Isotopic Ratio of Iron in Anthropogenic Aerosols and Evaluation of its Contribution to the Surface Ocean

NASA Astrophysics Data System (ADS)

Kurisu, M.; Iizuka, T.; Sakata, K.; Uematsu, M.; Takahashi, Y.

2015-12-01

It has been reported that phytoplankton growth in the High Nutrient-Low Chlorophyll (HNLC) regions is limited by dissolved iron (DFe) concentration (e.g., Martin and Fitzwater, 1988). Aerosol is known as one of the dominant sources of DFe to the ocean and classified into two origins such as anthropogenic and natural. A series of recent studies showed that Fe in anthropogenic aerosols is more soluble than that in natural aerosols (Takahashi et al., 2013) and has lower isotopic ratio (Mead et al., 2013). However, the difference between Fe isotopic ratio　(δ56Fe: [(56Fe/54Fe)sample/(56Fe/54Fe)IRMM-14]-1) of two origins reported in Mead et al. (2013) is not so large compared with the standard deviation. Therefore, the aim of this study is to determine Fe species and δ56Fe in anthropogenic aerosols more accurately and to evaluate its contribution to the ocean surface. Iron species were determined by X-ray absorption fine structure (XAFS) analysis, while δ56Fe in size-fractionated aerosols were measured by MC-ICP-MS (NEPTUNE Plus) after chemical separation using anion exchange resin. Dominant Fe species in the samples were, ferrihydrite, hematite, and biotite. It was also revealed that coarse particles contained a larger amount of biotite and that fine particles contained a larger amount of hematite, which suggested that anthropogenic aerosols were emitted during combustion processes. In addition, results of Fe isotopic ratio analysis suggested that δ56Fe of coarse particles were around +0.25‰, whereas that of fine particles were -0.5 ˜ -2‰, which was lower than the δ56Fe in anthropogenic aerosol by Mead et al. (2013). The size-fractionated sampling made it possible to determine the δ56Fe in anthropogenic aerosol. Soluble component in fine particles extracted by simulated rain water also showed much lower δ56Fe (δ56Fe = -3.9±0.12‰), suggesting that anthropogenic Fe has much lower isotopic ratio. The remarkably low δ56Fe may be caused by the anthropogenic combustion process. The δ56Fe in anthropogenic aerosols measured here is important to model the budget of iron in the surface ocean.

Physiotherapy students' perceptions of learning in clinical practice in Sweden and India.

PubMed

Gard, Gunvor; Dagis, Daina

2016-01-01

It is reasonable to assume that conditions for learning differ between universities and countries. Increased understanding of similarities and differences of student's perceptions of learning environment can be useful in the development of the physiotherapy education as well as of the profession as such. Through international comparisons the benefits and challenges of educational programmes can be made transparent and serve as base for improvement. The objective of this study is to describe and compare physiotherapy students' perceptions of their learning environment in clinical practice in India and Sweden. A questionnaire study was performed, covering physiotherapy students' perceptions of their clinical learning environment, the physiotherapy supervisor within the clinical context, their supervisory relationship and the role of the clinical supervisor at two Universities, Luleå in Sweden and Amity in New Delhi, India. Undergraduate students at two physiotherapy programmes, in New Delhi, India and in Luleå, Sweden participated in the questionnaire study. In general, both groups had high rankings of their perceptions of the clinical learning environment. The Swedish students ranked individual supervision, participation in meetings, the supervisor as a resource, being a part of the team and giving them valuable feedback higher than the Indian group. The supervisory relationship was equally satisfying in groups, providing valuable feedback and acknowledging equality and mutuality in the relationship. The Indian group ranked the supervisor as a colleague, as a support in learning, and that he/she made them feel comfortable in meetings higher than the Swedish group. Both groups had high ratings of the supervisor and the clinical learning context Participation at meetings was higher rated in the Swedish and the supervisor as a support in learning higher rated of the Indian students. Copyright © 2015 Elsevier Ltd. All rights reserved.

Energy Feedback from X-ray Binaries in the Early Universe

NASA Technical Reports Server (NTRS)

Fragos, T.; Lehmer, B..; Naoz, S.; Zezas, A.; Basu-Zych, A.

2013-01-01

X-ray photons, because of their long mean-free paths, can easily escape the galactic environments where they are produced, and interact at long distances with the intergalactic medium, potentially having a significant contribution to the heating and reionization of the early universe. The two most important sources of X-ray photons in the universe are active galactic nuclei (AGNs) and X-ray binaries (XRBs). In this Letter we use results from detailed, large scale population synthesis simulations to study the energy feedback of XRBs, from the first galaxies (z (redshift) approximately equal to 20) until today.We estimate that X-ray emission from XRBs dominates over AGN at z (redshift) greater than or approximately equal to 6-8. The shape of the spectral energy distribution of the emission from XRBs shows little change with redshift, in contrast to its normalization which evolves by approximately 4 orders of magnitude, primarily due to the evolution of the cosmic star-formation rate. However, the metallicity and the mean stellar age of a given XRB population affect significantly its X-ray output. Specifically, the X-ray luminosity from high-mass XRBs per unit of star-formation rate varies an order of magnitude going from solar metallicity to less than 10% solar, and the X-ray luminosity from low-mass XRBs per unit of stellar mass peaks at an age of approximately 300 Myr (million years) and then decreases gradually at later times, showing little variation for mean stellar ages 3 Gyr (Giga years, or billion years). Finally, we provide analytical and tabulated prescriptions for the energy output of XRBs, that can be directly incorporated in cosmological simulations.

Conditions-Based Learning Theory as a Framework for Comparative-Effectiveness Reviews: A Worked Example.

PubMed

Rourke, Liam; Leong, Jessica; Chatterly, Patricia

2018-02-16

Phenomenon: An evidence-informed era of medical education encourages the generation and use of comparative-effectiveness reviews, yet the reviews often conclude, curiously, that all instructional approaches are equally effective. We used a conditions-based learning theory to structure a review of the comparative-effectiveness literature on electrocardiogram instruction. We searched MEDLINE, EMBASE (Ovid), ERIC (Ovid), PsycINFO (Ovid), and CINAHL (EBSCO) from inception to June 2016. We selected prospective studies that examined the effect of instructional interventions on participants' knowledge and skill with electrocardiogram interpretation. Two reviewers extracted information on the quality of the studies, the effect of instruction on the acquisition of knowledge and skill, and instructional quality. Instructional quality is an index of the extent to which instruction incorporates 4 practices of Gagne's conditions-based learning theory: presenting information, eliciting performance, providing feedback, and assessing learning. Twenty-five studies (3,286 participants) evaluating 47 instructional interventions were synthesized. The methodological quality of most studies was moderate. Instructional quality varied: All interventions presented information and assessed learning, but fewer than half elicited performances or provided feedback. Instructional interventions that incorporated all 4 components improved trainees' abilities considerably more than those that incorporated 3 or fewer; respectively, standardized mean difference (SMD) = 2.80, 95% confidence interval (CI) [2.05, 3.55], versus SMD = 1.44, 95% CI [1.18, 1.69]. Studies that compared "innovative" to "traditional" types of instruction did not yield a significant pooled effect: SMD = 0.18, 95% CI [-0.09, 0.45]. Insights: The use of a conditions-based learning theory to organize the comparative-effectiveness literature reveals differences in the instructional impact of different instructional approaches. It overturns the unlikely, but common, conclusion that all approaches are equally effective.

Adaptive gain, equalization, and wavelength stabilization techniques for silicon photonic microring resonator-based optical receivers

NASA Astrophysics Data System (ADS)

Palermo, Samuel; Chiang, Patrick; Yu, Kunzhi; Bai, Rui; Li, Cheng; Chen, Chin-Hui; Fiorentino, Marco; Beausoleil, Ray; Li, Hao; Shafik, Ayman; Titriku, Alex

2016-03-01

Interconnect architectures based on high-Q silicon photonic microring resonator devices offer a promising solution to address the dramatic increase in datacenter I/O bandwidth demands due to their ability to realize wavelength-division multiplexing (WDM) in a compact and energy efficient manner. However, challenges exist in realizing efficient receivers for these systems due to varying per-channel link budgets, sensitivity requirements, and ring resonance wavelength shifts. This paper reports on adaptive optical receiver design techniques which address these issues and have been demonstrated in two hybrid-integrated prototypes based on microring drop filters and waveguide photodetectors implemented in a 130nm SOI process and high-speed optical front-ends designed in 65nm CMOS. A 10Gb/s powerscalable architecture employs supply voltage scaling of a three inverter-stage transimpedance amplifier (TIA) that is adapted with an eye-monitor control loop to yield the necessary sensitivity for a given channel. As reduction of TIA input-referred noise is more critical at higher data rates, a 25Gb/s design utilizes a large input-stage feedback resistor TIA cascaded with a continuous-time linear equalizer (CTLE) that compensates for the increased input pole. When tested with a waveguide Ge PD with 0.45A/W responsivity, this topology achieves 25Gb/s operation with -8.2dBm sensitivity at a BER=10-12. In order to address microring drop filters sensitivity to fabrication tolerances and thermal variations, efficient wavelength-stabilization control loops are necessary. A peak-power-based monitoring loop which locks the drop filter to the input wavelength, while achieving compatibility with the high-speed TIA offset-correction feedback loop is implemented with a 0.7nm tuning range at 43μW/GHz efficiency.

Social pain and social gain in the adolescent brain: A common neural circuitry underlying both positive and negative social evaluation

PubMed Central

Dalgleish, Tim; Walsh, Nicholas D.; Mobbs, Dean; Schweizer, Susanne; van Harmelen, Anne-Laura; Dunn, Barnaby; Dunn, Valerie; Goodyer, Ian; Stretton, Jason

2017-01-01

Social interaction inherently involves the subjective evaluation of cues salient to social inclusion and exclusion. Testifying to the importance of such social cues, parts of the neural system dedicated to the detection of physical pain, the dorsal anterior cingulate cortex (dACC) and anterior insula (AI), have been shown to be equally sensitive to the detection of social pain experienced after social exclusion. However, recent work suggests that this dACC-AI matrix may index any socially pertinent information. We directly tested the hypothesis that the dACC-AI would respond to cues of both inclusion and exclusion, using a novel social feedback fMRI paradigm in a population-derived sample of adolescents. We show that the dACC and left AI are commonly activated by feedback cues of inclusion and exclusion. Our findings suggest that theoretical accounts of the dACC-AI network as a neural alarm system restricted within the social domain to the processing of signals of exclusion require significant revision. PMID:28169323

Do It Yourself (DIY) Earth Science Collaboratories Using Best Practices and Breakthrough Technologies

NASA Astrophysics Data System (ADS)

Stephan, E.

2017-12-01

The objective of published earth science study data results and literature on the Web should be to provide a means to integrate discoverable science resources through an open collaborative-Web. At the core of any open science collaborative infrastructure is the ability to discover, manage and ultimately use relevant data accessible to the collaboration. Equally important are the relationships between people, applications, services, and publications, which capture critical contextual knowledge that enable their effective use. While contributions of either irreproducible or costly data can be a great asset the inability of users being able to use the data intelligently or make sense of it, makes these investments not usable. An ability to describe ad-hoc discoverable usage methodologies, provide feedback to data producers, and identify and cite data in a systematic way by leveraging existing Web-enabled off the shelf technology is needed. Fortunately many break-through advancements in data publication best practices and government, open source, and commercial investments support consumers who can provide feedback, share experiences, and contribute back to the earth science ecosystem.

Hybrid PD and effective multi-mode positive position feedback control for slewing and vibration suppression of a smart flexible manipulator

NASA Astrophysics Data System (ADS)

Lou, Jun-qiang; Wei, Yan-ding; Yang, Yi-ling; Xie, Feng-ran

2015-03-01

A hybrid control strategy for slewing and vibration suppression of a smart flexible manipulator is presented in this paper. It consists of a proportional derivative controller to realize motion control, and an effective multi-mode positive position feedback (EMPPF) controller to suppress the multi-mode vibration. Rather than treat each mode equally as the standard multi-mode PPF, the essence of the EMPPF is that control forces of different modes are applied according to the mode parameters of the respective modes, so the vibration modes with less vibration energy receive fewer control forces. Stability conditions for the close loop system are established through stability analysis. Optimal parameters of the EMPPF controller are obtained using the method of root locus analysis. The performance of the proposed strategy is demonstrated by simulation and experiments. Experimental results show that the first two vibration modes of the manipulator are effectively suppressed. The setting time of the setup descends approximately 55%, reaching 3.12 s from 5.67 s.

Dissociable contributions of motor-execution and action-observation to intramanual transfer.

PubMed

Hayes, Spencer J; Elliott, Digby; Andrew, Matthew; Roberts, James W; Bennett, Simon J

2012-09-01

We examined the hypothesis that different processes and representations are associated with the learning of a movement sequence through motor-execution and action-observation. Following a pre-test in which participants attempted to achieve an absolute, and relative, time goal in a sequential goal-directed aiming movement, participants received either physical or observational practice with feedback. Post-test performance indicated that motor-execution and action-observation participants learned equally well. Participants then transferred to conditions where the gain between the limb movements and their visual consequences were manipulated. Under both bigger and smaller transfer conditions, motor-execution and action-observation participants exhibited similar intramanual transfer of absolute timing. However, participants in the action-observation group exhibited superior transfer of relative timing than the motor-execution group. These findings suggest that learning via action-observation is underpinned by a visual-spatial representation, while learning via motor-execution depends more on specific force-time planning (feed forward) and afferent processing associated with sensorimotor feedback. These behavioural effects are discussed with reference to neural processes associated with striatum, cerebellum and motor cortical regions (pre-motor cortex; SMA; pre-SMA).

Nonlinear Algorithms for Channel Equalization and Map Symbol Detection.

NASA Astrophysics Data System (ADS)

Giridhar, K.

The transfer of information through a communication medium invariably results in various kinds of distortion to the transmitted signal. In this dissertation, a feed -forward neural network-based equalizer, and a family of maximum a posteriori (MAP) symbol detectors are proposed for signal recovery in the presence of intersymbol interference (ISI) and additive white Gaussian noise. The proposed neural network-based equalizer employs a novel bit-mapping strategy to handle multilevel data signals in an equivalent bipolar representation. It uses a training procedure to learn the channel characteristics, and at the end of training, the multilevel symbols are recovered from the corresponding inverse bit-mapping. When the channel characteristics are unknown and no training sequences are available, blind estimation of the channel (or its inverse) and simultaneous data recovery is required. Convergence properties of several existing Bussgang-type blind equalization algorithms are studied through computer simulations, and a unique gain independent approach is used to obtain a fair comparison of their rates of convergence. Although simple to implement, the slow convergence of these Bussgang-type blind equalizers make them unsuitable for many high data-rate applications. Rapidly converging blind algorithms based on the principle of MAP symbol-by -symbol detection are proposed, which adaptively estimate the channel impulse response (CIR) and simultaneously decode the received data sequence. Assuming a linear and Gaussian measurement model, the near-optimal blind MAP symbol detector (MAPSD) consists of a parallel bank of conditional Kalman channel estimators, where the conditioning is done on each possible data subsequence that can convolve with the CIR. This algorithm is also extended to the recovery of convolutionally encoded waveforms in the presence of ISI. Since the complexity of the MAPSD algorithm increases exponentially with the length of the assumed CIR, a suboptimal decision-feedback mechanism is introduced to truncate the channel memory "seen" by the MAPSD section. Also, simpler gradient-based updates for the channel estimates, and a metric pruning technique are used to further reduce the MAPSD complexity. Spatial diversity MAP combiners are developed to enhance the error rate performance and combat channel fading. As a first application of the MAPSD algorithm, dual-mode recovery techniques for TDMA (time-division multiple access) mobile radio signals are presented. Combined estimation of the symbol timing and the multipath parameters is proposed, using an auxiliary extended Kalman filter during the training cycle, and then tracking of the fading parameters is performed during the data cycle using the blind MAPSD algorithm. For the second application, a single-input receiver is employed to jointly recover cochannel narrowband signals. Assuming known channels, this two-stage joint MAPSD (JMAPSD) algorithm is compared to the optimal joint maximum likelihood sequence estimator, and to the joint decision-feedback detector. A blind MAPSD algorithm for the joint recovery of cochannel signals is also presented. Computer simulation results are provided to quantify the performance of the various algorithms proposed in this dissertation.

Homodyne versus photon-counting quantum trajectories for dissipative Kerr resonators with two-photon driving

NASA Astrophysics Data System (ADS)

Bartolo, Nicola; Minganti, Fabrizio; Lolli, Jared; Ciuti, Cristiano

2017-07-01

We investigate two different kinds of quantum trajectories for a nonlinear photon resonator subject to two-photon pumping, a configuration recently studied for the generation of photonic Schrödinger cat states. In the absence of feedback control and in the strong-driving limit, the steady-state density matrix is a statistical mixture of two states with equal weight. While along a single photon-counting trajectory the systems intermittently switches between an odd and an even cat state, we show that upon homodyne detection the situation is different. Indeed, homodyne quantum trajectories reveal switches between coherent states of opposite phase.

Can we influence prescribing patterns?

PubMed

Sbarbaro, J A

2001-09-15

A variety of programming techniques and methods of training have been employed to change physician behavior. Didactic continuing medical education lectures and clinical guidelines have had minimal impact, although endorsement of national professional guidelines by local opinion leaders appears to have a positive influence on the impact of professional guidelines. Interactive, hands-on workshops, performance reporting, and peer/patient feedback are also effective. Changing prescribing habits has been equally difficult. Drug utilization letters involving both pharmacist and physician have more impact than do letters sent only to the physician. Academic detailing, when properly executed, has been consistently effective. When combined with these strategies, closed formularies become a powerful tool in changing prescribing behavior.

Linewidth-tolerant real-time 40-Gbit/s 16-QAM self-homodyne detection using a pilot carrier and ISI suppression based on electronic digital processing.

PubMed

Nakamura, Moriya; Kamio, Yukiyoshi; Miyazaki, Tetsuya

2010-01-01

We experimentally demonstrate linewidth-tolerant real-time 40-Gbit/s(10-Gsymbol/s) 16-quadrature amplitude modulation. We achieved bit-error rates of <10(-9) using an external-cavity laser diode with a linewidth of 200 kHz and <10(-7) using a distributed-feedback laser diode with a linewidth of 30 MHz, thanks to the phase-noise canceling capability provided by self-homodyne detection using a pilot carrier. Pre-equalization based on digital signal processing was employed to suppress intersymbol interference caused by the limited-frequency bandwidth of electrical components.

Methane production as key to the greenhouse gas budget of thawing permafrost

NASA Astrophysics Data System (ADS)

Knoblauch, Christian; Beer, Christian; Liebner, Susanne; Grigoriev, Mikhail N.; Pfeiffer, Eva-Maria

2018-04-01

Permafrost thaw liberates frozen organic carbon, which is decomposed into carbon dioxide (CO2) and methane (CH4). The release of these greenhouse gases (GHGs) forms a positive feedback to atmospheric CO2 and CH4 concentrations and accelerates climate change1,2. Current studies report a minor importance of CH4 production in water-saturated (anoxic) permafrost soils3-6 and a stronger permafrost carbon-climate feedback from drained (oxic) soils1,7. Here we show through seven-year laboratory incubations that equal amounts of CO2 and CH4 are formed in thawing permafrost under anoxic conditions after stable CH4-producing microbial communities have established. Less permafrost carbon was mineralized under anoxic conditions but more CO2-carbon equivalents (CO2-Ce) were formed than under oxic conditions when the higher global warming potential (GWP) of CH4 is taken into account8. A model of organic carbon decomposition, calibrated with the observed decomposition data, predicts a higher loss of permafrost carbon under oxic conditions (113 ± 58 g CO2-C kgC-1 (kgC, kilograms of carbon)) by 2100, but a twice as high production of CO2-Ce (241 ± 138 g CO2-Ce kgC-1) under anoxic conditions. These findings challenge the view of a stronger permafrost carbon-climate feedback from drained soils1,7 and emphasize the importance of CH4 production in thawing permafrost on climate-relevant timescales.

Sex-ratio control erodes sexual selection, revealing evolutionary feedback from adaptive plasticity.

PubMed

Fawcett, Tim W; Kuijper, Bram; Weissing, Franz J; Pen, Ido

2011-09-20

Female choice is a powerful selective force, driving the elaboration of conspicuous male ornaments. This process of sexual selection has profound implications for many life-history decisions, including sex allocation. For example, females with attractive partners should produce more sons, because these sons will inherit their father's attractiveness and enjoy high mating success, thereby yielding greater fitness returns than daughters. However, previous research has overlooked the fact that there is a reciprocal feedback from life-history strategies to sexual selection. Here, using a simple mathematical model, we show that if mothers adaptively control offspring sex in relation to their partner's attractiveness, sexual selection is weakened and male ornamentation declines. This weakening occurs because the ability to determine offspring sex reduces the fitness difference between females with attractive and unattractive partners. We use individual-based, evolutionary simulations to show that this result holds under more biologically realistic conditions. Sexual selection and sex allocation thus interact in a dynamic fashion: The evolution of conspicuous male ornaments favors sex-ratio adjustment, but this conditional strategy then undermines the very same process that generated it, eroding sexual selection. We predict that, all else being equal, the most elaborate sexual displays should be seen in species with little or no control over offspring sex. The feedback process we have described points to a more general evolutionary principle, in which a conditional strategy weakens directional selection on another trait by reducing fitness differences.

Structural predictions for Correlated Electron Materials Using the Functional Dynamical Mean Field Theory Approach

NASA Astrophysics Data System (ADS)

Haule, Kristjan

2018-04-01

The Dynamical Mean Field Theory (DMFT) in combination with the band structure methods has been able to address reach physics of correlated materials, such as the fluctuating local moments, spin and orbital fluctuations, atomic multiplet physics and band formation on equal footing. Recently it is getting increasingly recognized that more predictive ab-initio theory of correlated systems needs to also address the feedback effect of the correlated electronic structure on the ionic positions, as the metal-insulator transition is almost always accompanied with considerable structural distortions. We will review recently developed extension of merger between the Density Functional Theory (DFT) and DMFT method, dubbed DFT+ embedded DMFT (DFT+eDMFT), whichsuccessfully addresses this challenge. It is based on the stationary Luttinger-Ward functional to minimize the numerical error, it subtracts the exact double-counting of DFT and DMFT, and implements self-consistent forces on all atoms in the unit cell. In a few examples, we will also show how the method elucidated the important feedback effect of correlations on crystal structure in rare earth nickelates to explain the mechanism of the metal-insulator transition. The method showed that such feedback effect is also essential to understand the dynamic stability of the high-temperature body-centered cubic phase of elemental iron, and in particular it predicted strong enhancement of the electron-phonon coupling over DFT values in FeSe, which was very recently verified by pioneering time-domain experiment.

Restoring the sense of touch with a prosthetic hand through a brain interface.

PubMed

Tabot, Gregg A; Dammann, John F; Berg, Joshua A; Tenore, Francesco V; Boback, Jessica L; Vogelstein, R Jacob; Bensmaia, Sliman J

2013-11-05

Our ability to manipulate objects dexterously relies fundamentally on sensory signals originating from the hand. To restore motor function with upper-limb neuroprostheses requires that somatosensory feedback be provided to the tetraplegic patient or amputee. Given the complexity of state-of-the-art prosthetic limbs and, thus, the huge state space they can traverse, it is desirable to minimize the need for the patient to learn associations between events impinging on the limb and arbitrary sensations. Accordingly, we have developed approaches to intuitively convey sensory information that is critical for object manipulation--information about contact location, pressure, and timing--through intracortical microstimulation of primary somatosensory cortex. In experiments with nonhuman primates, we show that we can elicit percepts that are projected to a localized patch of skin and that track the pressure exerted on the skin. In a real-time application, we demonstrate that animals can perform a tactile discrimination task equally well whether mechanical stimuli are delivered to their native fingers or to a prosthetic one. Finally, we propose that the timing of contact events can be signaled through phasic intracortical microstimulation at the onset and offset of object contact that mimics the ubiquitous on and off responses observed in primary somatosensory cortex to complement slowly varying pressure-related feedback. We anticipate that the proposed biomimetic feedback will considerably increase the dexterity and embodiment of upper-limb neuroprostheses and will constitute an important step in restoring touch to individuals who have lost it.

Evolution of restraint in a structured rock–paper–scissors community

PubMed Central

Nahum, Joshua R.; Harding, Brittany N.; Kerr, Benjamin

2011-01-01

It is not immediately clear how costly behavior that benefits others evolves by natural selection. By saving on inherent costs, individuals that do not contribute socially have a selective advantage over altruists if both types receive equal benefits. Restrained consumption of a common resource is a form of altruism. The cost of this kind of prudent behavior is that restrained individuals give up resources to less-restrained individuals. The benefit of restraint is that better resource management may prolong the persistence of the group. One way to dodge the problem of defection is for altruists to interact disproportionately with other altruists. With limited dispersal, restrained individuals persist because of interaction with like types, whereas it is the unrestrained individuals that must face the negative long-term consequences of their rapacity. Here, we study the evolution of restraint in a community of three competitors exhibiting a nontransitive (rock–paper–scissors) relationship. The nontransitivity ensures a form of negative feedback, whereby improvement in growth of one competitor has the counterintuitive consequence of lowering the density of that improved player. This negative feedback generates detrimental long-term consequences for unrestrained growth. Using both computer simulations and evolution experiments with a nontransitive community of Escherichia coli, we find that restrained growth can evolve under conditions of limited dispersal in which negative feedback is present. This research, thus, highlights a set of ecological conditions sufficient for the evolution of one form of altruism. PMID:21690371

Evolution of restraint in a structured rock-paper-scissors community.

PubMed

Nahum, Joshua R; Harding, Brittany N; Kerr, Benjamin

2011-06-28

It is not immediately clear how costly behavior that benefits others evolves by natural selection. By saving on inherent costs, individuals that do not contribute socially have a selective advantage over altruists if both types receive equal benefits. Restrained consumption of a common resource is a form of altruism. The cost of this kind of prudent behavior is that restrained individuals give up resources to less-restrained individuals. The benefit of restraint is that better resource management may prolong the persistence of the group. One way to dodge the problem of defection is for altruists to interact disproportionately with other altruists. With limited dispersal, restrained individuals persist because of interaction with like types, whereas it is the unrestrained individuals that must face the negative long-term consequences of their rapacity. Here, we study the evolution of restraint in a community of three competitors exhibiting a nontransitive (rock-paper-scissors) relationship. The nontransitivity ensures a form of negative feedback, whereby improvement in growth of one competitor has the counterintuitive consequence of lowering the density of that improved player. This negative feedback generates detrimental long-term consequences for unrestrained growth. Using both computer simulations and evolution experiments with a nontransitive community of Escherichia coli, we find that restrained growth can evolve under conditions of limited dispersal in which negative feedback is present. This research, thus, highlights a set of ecological conditions sufficient for the evolution of one form of altruism.

Scaling Relations from Sunyaev-Zel'dovich Effect and Chandra X-ray Measurements of High-Redshift Galaxy Clusters

NASA Technical Reports Server (NTRS)

Bonamente, Massimiliano; Joy, Marshall; LaRoque, Samuel J.; Carlstrom, John E.; Nagai, Daisuke; Marrone, Dan

2007-01-01

We present Sunyaev-Zel'dovich Effect (SZE) scaling relations for 38 massive galaxy clusters at redshifts 0.14 less than or equal to z less than or equal to 0.89, observed with both the Chandra X-ray Observatory and the centimeter-wave SZE imaging system at the BIMA and OVRO interferometric arrays. An isothermal ,Beta-model with central 100 kpc excluded from the X-ray data is used to model the intracluster medium and to measure global cluster properties. For each Cluster, we measure the X-ray spectroscopic temperature, SZE gas mass, total mass. and integrated Compton-gamma parameters within r(sub 2500). Our measurements are in agreement with the expectations based on a simple self-similar model of cluster formation and evolution. We compare the cluster properties derived from our SZE observations with and without Chandra spatial and spectral information and find them to be in good agreement: We compare our results with cosmological numerical simulations, and find that simulations that include radiative cooling, star formation and feedback match well both the slope and normalization of our SZE scaling relations.

High-throughput mathematical analysis identifies Turing networks for patterning with equally diffusing signals.

PubMed

Marcon, Luciano; Diego, Xavier; Sharpe, James; Müller, Patrick

2016-04-08

The Turing reaction-diffusion model explains how identical cells can self-organize to form spatial patterns. It has been suggested that extracellular signaling molecules with different diffusion coefficients underlie this model, but the contribution of cell-autonomous signaling components is largely unknown. We developed an automated mathematical analysis to derive a catalog of realistic Turing networks. This analysis reveals that in the presence of cell-autonomous factors, networks can form a pattern with equally diffusing signals and even for any combination of diffusion coefficients. We provide a software (available at http://www.RDNets.com) to explore these networks and to constrain topologies with qualitative and quantitative experimental data. We use the software to examine the self-organizing networks that control embryonic axis specification and digit patterning. Finally, we demonstrate how existing synthetic circuits can be extended with additional feedbacks to form Turing reaction-diffusion systems. Our study offers a new theoretical framework to understand multicellular pattern formation and enables the wide-spread use of mathematical biology to engineer synthetic patterning systems.

High-throughput mathematical analysis identifies Turing networks for patterning with equally diffusing signals

PubMed Central

Marcon, Luciano; Diego, Xavier; Sharpe, James; Müller, Patrick

2016-01-01

The Turing reaction-diffusion model explains how identical cells can self-organize to form spatial patterns. It has been suggested that extracellular signaling molecules with different diffusion coefficients underlie this model, but the contribution of cell-autonomous signaling components is largely unknown. We developed an automated mathematical analysis to derive a catalog of realistic Turing networks. This analysis reveals that in the presence of cell-autonomous factors, networks can form a pattern with equally diffusing signals and even for any combination of diffusion coefficients. We provide a software (available at http://www.RDNets.com) to explore these networks and to constrain topologies with qualitative and quantitative experimental data. We use the software to examine the self-organizing networks that control embryonic axis specification and digit patterning. Finally, we demonstrate how existing synthetic circuits can be extended with additional feedbacks to form Turing reaction-diffusion systems. Our study offers a new theoretical framework to understand multicellular pattern formation and enables the wide-spread use of mathematical biology to engineer synthetic patterning systems. DOI: http://dx.doi.org/10.7554/eLife.14022.001 PMID:27058171

[The "stop violence" campaign of the Swiss Conference of Equality Officers].

PubMed

1998-01-01

The campaign "Stop Domestic Violence against Women" (referred to below as "Stop Violence") is a prevention campaign of the Swiss Conference of Equality Officers. It has been primarily focussed an heightening public awareness of violence against women in relationships with the opposite sex and offering victims and experts a refuge and meeting place. Central elements of the campaign: public service announcements on television and in the radio broadcast at various times of the day and the Info Line, a trilingual hot line and contact point specially set up by the campaign for victims and experts. The evaluation was designed to describe and estimate the type and extent of phone contacts with victims, experts and other callers. It was also designed to survey the opinion of the campaign on the part of those confronted with the victims of domestic violence on a daily basis, i.e. the staff of women's shelters. Consequently, the goal of the evaluation was to gather feedback on the campaign as well as assess the benefits and effect of the Info Line.

Nonlinear feedback in a six-dimensional Lorenz Model: impact of an additional heating term

NASA Astrophysics Data System (ADS)

Shen, B.-W.

2015-03-01

In this study, a six-dimensional Lorenz model (6DLM) is derived, based on a recent study using a five-dimensional (5-D) Lorenz model (LM), in order to examine the impact of an additional mode and its accompanying heating term on solution stability. The new mode added to improve the representation of the steamfunction is referred to as a secondary streamfunction mode, while the two additional modes, that appear in both the 6DLM and 5DLM but not in the original LM, are referred to as secondary temperature modes. Two energy conservation relationships of the 6DLM are first derived in the dissipationless limit. The impact of three additional modes on solution stability is examined by comparing numerical solutions and ensemble Lyapunov exponents of the 6DLM and 5DLM as well as the original LM. For the onset of chaos, the critical value of the normalized Rayleigh number (rc) is determined to be 41.1. The critical value is larger than that in the 3DLM (rc ~ 24.74), but slightly smaller than the one in the 5DLM (rc ~ 42.9). A stability analysis and numerical experiments obtained using generalized LMs, with or without simplifications, suggest the following: (1) negative nonlinear feedback in association with the secondary temperature modes, as first identified using the 5DLM, plays a dominant role in providing feedback for improving the solution's stability of the 6DLM, (2) the additional heating term in association with the secondary streamfunction mode may destabilize the solution, and (3) overall feedback due to the secondary streamfunction mode is much smaller than the feedback due to the secondary temperature modes; therefore, the critical Rayleigh number of the 6DLM is comparable to that of the 5DLM. The 5DLM and 6DLM collectively suggest different roles for small-scale processes (i.e., stabilization vs. destabilization), consistent with the following statement by Lorenz (1972): If the flap of a butterfly's wings can be instrumental in generating a tornado, it can equally well be instrumental in preventing a tornado. The implications of this and previous work, as well as future work, are also discussed.

Nonlinear feedback in a six-dimensional Lorenz model: impact of an additional heating term

NASA Astrophysics Data System (ADS)

Shen, B.-W.

2015-12-01

In this study, a six-dimensional Lorenz model (6DLM) is derived, based on a recent study using a five-dimensional (5-D) Lorenz model (LM), in order to examine the impact of an additional mode and its accompanying heating term on solution stability. The new mode added to improve the representation of the streamfunction is referred to as a secondary streamfunction mode, while the two additional modes, which appear in both the 6DLM and 5DLM but not in the original LM, are referred to as secondary temperature modes. Two energy conservation relationships of the 6DLM are first derived in the dissipationless limit. The impact of three additional modes on solution stability is examined by comparing numerical solutions and ensemble Lyapunov exponents of the 6DLM and 5DLM as well as the original LM. For the onset of chaos, the critical value of the normalized Rayleigh number (rc) is determined to be 41.1. The critical value is larger than that in the 3DLM (rc ~ 24.74), but slightly smaller than the one in the 5DLM (rc ~ 42.9). A stability analysis and numerical experiments obtained using generalized LMs, with or without simplifications, suggest the following: (1) negative nonlinear feedback in association with the secondary temperature modes, as first identified using the 5DLM, plays a dominant role in providing feedback for improving the solution's stability of the 6DLM, (2) the additional heating term in association with the secondary streamfunction mode may destabilize the solution, and (3) overall feedback due to the secondary streamfunction mode is much smaller than the feedback due to the secondary temperature modes; therefore, the critical Rayleigh number of the 6DLM is comparable to that of the 5DLM. The 5DLM and 6DLM collectively suggest different roles for small-scale processes (i.e., stabilization vs. destabilization), consistent with the following statement by Lorenz (1972): "If the flap of a butterfly's wings can be instrumental in generating a tornado, it can equally well be instrumental in preventing a tornado." The implications of this and previous work, as well as future work, are also discussed.

Office of Equal Opportunity Programs

NASA Technical Reports Server (NTRS)

Chin, Jennifer L.

2004-01-01

The NASA Glenn Office of Equal Opportunity Programs works to provide quality service for all programs and/or to assist the Center in becoming a model workplace. During the summer of 2004, I worked with Deborah Cotleur along with other staff members to create and modify customer satisfaction surveys. This office aims to assist in developing a model workplace by providing functions as a change agent to the center by serving as an advisor to management to ensure equity throughout the Center. In addition, the office serves as a mediator for the Center in addressing issues and concerns. Lastly, the office provides assistance to employees to enable attainment of personal and organizational goals. The Office of Equal Opportunities is a staff office which reports and provides advice to the Center Director and Executive Leadership, implements laws, regulations, and presidential executive orders, and provides center wide leadership and assistance to NASA GRC employees. Some of the major responsibilities of the office include working with the discrimination complaints program, special emphasis programs (advisory groups), management support, monitoring and evaluation, contract compliance, and community outreach. During my internship in this office, my main objective was to create four customer satisfaction surveys based on EO retreats, EO observances, EO advisory boards, and EO mediation/counseling. I created these surveys after conducting research on past events and surveys as well as similar survey research created and conducted by other NASA centers, program for EO Advisory group members, leadership training sessions for supervisors, preventing sexual harassment training sessions, and observance events. I also conducted research on the style and format from feedback surveys from the Marshall Equal Opportunity website, the Goddard website, and the main NASA website. Using the material from the Office of Equal Opportunity Programs at Glenn Research Center along with my previous research, I created four customer satisfaction surveys. Additional information is included in the original extended abstract.

Accurate landmarking of three-dimensional facial data in the presence of facial expressions and occlusions using a three-dimensional statistical facial feature model.

PubMed

Zhao, Xi; Dellandréa, Emmanuel; Chen, Liming; Kakadiaris, Ioannis A

2011-10-01

Three-dimensional face landmarking aims at automatically localizing facial landmarks and has a wide range of applications (e.g., face recognition, face tracking, and facial expression analysis). Existing methods assume neutral facial expressions and unoccluded faces. In this paper, we propose a general learning-based framework for reliable landmark localization on 3-D facial data under challenging conditions (i.e., facial expressions and occlusions). Our approach relies on a statistical model, called 3-D statistical facial feature model, which learns both the global variations in configurational relationships between landmarks and the local variations of texture and geometry around each landmark. Based on this model, we further propose an occlusion classifier and a fitting algorithm. Results from experiments on three publicly available 3-D face databases (FRGC, BU-3-DFE, and Bosphorus) demonstrate the effectiveness of our approach, in terms of landmarking accuracy and robustness, in the presence of expressions and occlusions.

Computation of load performance and other parameters of extra high speed modified Lundell alternators from 3D-FE magnetic field solutions

NASA Technical Reports Server (NTRS)

Wang, R.; Demerdash, N. A.

1992-01-01

The combined magnetic vector potential - magnetic scalar potential method of computation of 3D magnetic fields by finite elements, introduced in a companion paper, in combination with state modeling in the abc-frame of reference, are used for global 3D magnetic field analysis and machine performance computation under rated load and overload condition in an example 14.3 kVA modified Lundell alternator. The results vividly demonstrate the 3D nature of the magnetic field in such machines, and show how this model can be used as an excellent tool for computation of flux density distributions, armature current and voltage waveform profiles and harmonic contents, as well as computation of torque profiles and ripples. Use of the model in gaining insight into locations of regions in the magnetic circuit with heavy degrees of saturation is demonstrated. Experimental results which correlate well with the simulations of the load case are given.

Extra high speed modified Lundell alternator parameters and open/short-circuit characteristics from global 3D-FE magnetic field solutions

NASA Astrophysics Data System (ADS)

Wang, R.; Demerdash, N. A.

1992-06-01

The combined magnetic vector potential - magnetic scalar potential method of computation of 3D magnetic fields by finite elements, introduced in a companion paper, is used for global 3D field analysis and machine performance computations under open-circuit and short-circuit conditions for an example 14.3 kVA modified Lundell alternator, whose magnetic field is of intrinsic 3D nature. The computed voltages and currents under these machine test conditions were verified and found to be in very good agreement with corresponding test data. Results of use of this modelling and computation method in the study of a design alteration example, in which the stator stack length of the example alternator is stretched in order to increase voltage and volt-ampere rating, are given here. These results demonstrate the inadequacy of conventional 2D-based design concepts and the imperative of use of this type of 3D magnetic field modelling in the design and investigation of such machines.

Volcanic ash as an oceanic iron source and sink

NASA Astrophysics Data System (ADS)

Rogan, Nicholas; Achterberg, Eric P.; Le Moigne, Frédéric A. C.; Marsay, Chris M.; Tagliabue, Alessandro; Williams, Richard G.

2016-03-01

Volcanic ash deposition to the ocean forms a natural source of iron (Fe) to surface water microbial communities. Inputs of lithogenic material may also facilitate Fe removal through scavenging. Combining dissolved Fe (dFe) and thorium-234 observations alongside modeling, we investigate scavenging of Fe in the North Atlantic following the Eyjafjallajökull volcanic eruption. Under typical conditions biogenic particles dominate scavenging, whereas ash particles dominate during the eruption. The size of particles is important as smaller scavenging particles can become saturated with surface-associated ions. Model simulations indicate that ash deposition associated with Eyjafjallajökull likely led to net Fe removal. Our model suggests a threefold greater stimulation of biological activity if ash deposition had occurred later in the growing season when the region was Fe limited. The implications of ash particle scavenging, eruption timing, and particle saturation need to be considered when assessing the impact of ash deposition on the ocean Fe cycle and productivity.

Extra high speed modified Lundell alternator parameters and open/short-circuit characteristics from global 3D-FE magnetic field solutions

NASA Technical Reports Server (NTRS)

Wang, R.; Demerdash, N. A.

1992-01-01

The combined magnetic vector potential - magnetic scalar potential method of computation of 3D magnetic fields by finite elements, introduced in a companion paper, is used for global 3D field analysis and machine performance computations under open-circuit and short-circuit conditions for an example 14.3 kVA modified Lundell alternator, whose magnetic field is of intrinsic 3D nature. The computed voltages and currents under these machine test conditions were verified and found to be in very good agreement with corresponding test data. Results of use of this modelling and computation method in the study of a design alteration example, in which the stator stack length of the example alternator is stretched in order to increase voltage and volt-ampere rating, are given here. These results demonstrate the inadequacy of conventional 2D-based design concepts and the imperative of use of this type of 3D magnetic field modelling in the design and investigation of such machines.

Negative reinforcement impairs overnight memory consolidation.

PubMed

Stamm, Andrew W; Nguyen, Nam D; Seicol, Benjamin J; Fagan, Abigail; Oh, Angela; Drumm, Michael; Lundt, Maureen; Stickgold, Robert; Wamsley, Erin J

2014-11-01

Post-learning sleep is beneficial for human memory. However, it may be that not all memories benefit equally from sleep. Here, we manipulated a spatial learning task using monetary reward and performance feedback, asking whether enhancing the salience of the task would augment overnight memory consolidation and alter its incorporation into dreaming. Contrary to our hypothesis, we found that the addition of reward impaired overnight consolidation of spatial memory. Our findings seemingly contradict prior reports that enhancing the reward value of learned information augments sleep-dependent memory processing. Given that the reward followed a negative reinforcement paradigm, consolidation may have been impaired via a stress-related mechanism. © 2014 Stamm et al.; Published by Cold Spring Harbor Laboratory Press.

The automated ground network system

NASA Technical Reports Server (NTRS)

Smith, Miles T.; Militch, Peter N.

1993-01-01

The primary goal of the Automated Ground Network System (AGNS) project is to reduce Ground Network (GN) station life-cycle costs. To accomplish this goal, the AGNS project will employ an object-oriented approach to develop a new infrastructure that will permit continuous application of new technologies and methodologies to the Ground Network's class of problems. The AGNS project is a Total Quality (TQ) project. Through use of an open collaborative development environment, developers and users will have equal input into the end-to-end design and development process. This will permit direct user input and feedback and will enable rapid prototyping for requirements clarification. This paper describes the AGNS objectives, operations concept, and proposed design.

Virtual active touch using randomly patterned intracortical microstimulation.

PubMed

O'Doherty, Joseph E; Lebedev, Mikhail A; Li, Zheng; Nicolelis, Miguel A L

2012-01-01

Intracortical microstimulation (ICMS) has promise as a means for delivering somatosensory feedback in neuroprosthetic systems. Various tactile sensations could be encoded by temporal, spatial, or spatiotemporal patterns of ICMS. However, the applicability of temporal patterns of ICMS to artificial tactile sensation during active exploration is unknown, as is the minimum discriminable difference between temporally modulated ICMS patterns. We trained rhesus monkeys in an active exploration task in which they discriminated periodic pulse-trains of ICMS (200 Hz bursts at a 10 Hz secondary frequency) from pulse trains with the same average pulse rate, but distorted periodicity (200 Hz bursts at a variable instantaneous secondary frequency). The statistics of the aperiodic pulse trains were drawn from a gamma distribution with mean inter-burst intervals equal to those of the periodic pulse trains. The monkeys distinguished periodic pulse trains from aperiodic pulse trains with coefficients of variation 0.25 or greater. Reconstruction of movement kinematics, extracted from the activity of neuronal populations recorded in the sensorimotor cortex concurrent with the delivery of ICMS feedback, improved when the recording intervals affected by ICMS artifacts were removed from analysis. These results add to the growing evidence that temporally patterned ICMS can be used to simulate a tactile sense for neuroprosthetic devices.

Reengineering of the feedback-inhibition enzyme N-acetyl-L-glutamate kinase to enhance L-arginine production in Corynebacterium crenatum.

PubMed

Zhang, Jingjing; Xu, Meijuan; Ge, Xiaoxun; Zhang, Xian; Yang, Taowei; Xu, Zhenghong; Rao, Zhiming

2017-02-01

N-acetyl-L-glutamate kinase (NAGK) catalyzes the second step of L-arginine biosynthesis and is inhibited by L-arginine in Corynebacterium crenatum. To ascertain the basis for the arginine sensitivity of CcNAGK, residue E19 which located at the entrance of the Arginine-ring was subjected to site-saturated mutagenesis and we successfully illustrated the inhibition-resistant mechanism. Typically, the E19Y mutant displayed the greatest deregulation of L-arginine feedback inhibition. An equally important strategy is to improve the catalytic activity and thermostability of CcNAGK. For further strain improvement, we used site-directed mutagenesis to identify mutations that improve CcNAGK. Results identified variants I74V, F91H and K234T display higher specific activity and thermostability. The L-arginine yield and productivity of the recombinant strain C. crenatum SYPA-EH3 (which possesses a combination of all four mutant sites, E19Y/I74V/F91H/K234T) reached 61.2 and 0.638 g/L/h, respectively, after 96 h in 5 L bioreactor fermentation, an increase of approximately 41.8% compared with the initial strain.

A comparative study of efficacy of emg bio-feedback and progressive muscular relaxation in tension headache.

PubMed

Gada, M T

1984-04-01

The aim of the present study was to find out efficacy of frontalis EMG Biofeedback therapy, deep muscular relaxation therapy and compare the efficacy of both in cases of tension headache. During two week basal-data recording period all patients were taught deep muscular relaxation by Jacobson's technique. Simultaneously patients were instructed to keep headache diary. Headache diary yielded three different parameters a) number of headache-free days per week, b) peak headache intensity (or each week and c) average daily headache activity score per week. These parameters were used to find out therapeutic efficacy of each treatment. Patients were randomly divided in two groups. EMG Biofeedback group was given frontalis EMG feedback through EMG J 33 muscle trainer of Cyborg Corporation (U.S.A.). Patients in each group were given 20 sessions (two sessions per week); each session lasting 30 minutes. Patients were instructed to practice at least one 30 minute session of relaxation at home. The data were subjected to statistical calculation. The results indicate that frontalis EMG Biofeedback therapy and deep muscle relaxation therapy are significantly effective in cases of tension headache. Both treatments are equally effective. The findings are discussed in relation to Indian situation.

Laryngeal Aerodynamics in Children with Hearing Impairment versus Age and Height Matched Normal Hearing Peers.

PubMed

Das, Barshapriya; Chatterjee, Indranil; Kumar, Suman

2013-01-01

Lack of proper auditory feedback in hearing-impaired subjects results in functional voice disorder. It is directly related to discoordination of intrinsic and extrinsic laryngeal muscles and disturbed contraction and relaxation of antagonistic muscles. A total of twenty children in the age range of 5-10 years were considered for the study. They were divided into two groups: normal hearing children and hearing aid user children. Results showed a significant difference in the vital capacity, maximum sustained phonation, and fast adduction abduction rate having equal variance for normal and hearing aid user children, respectively, but no significant difference was found in the peak flow value with being statistically significant. A reduced vital capacity in hearing aid user children suggests a limited use of the lung volume for speech production. It may be inferred from the study that the hearing aid user children have poor vocal proficiency which is reflected in their voice. The use of voicing component in hearing impaired subjects is seen due to improper auditory feedback. It was found that there was a significant difference in the vital capacity, maximum sustained phonation (MSP), and fast adduction abduction rate and no significant difference in the peak flow.

A digital clock recovery algorithm based on chromatic dispersion and polarization mode dispersion feedback dual phase detection for coherent optical transmission systems

NASA Astrophysics Data System (ADS)

Liu, Bo; Xin, Xiangjun; Zhang, Lijia; Wang, Fu; Zhang, Qi

2018-02-01

A new feedback symbol timing recovery technique using timing estimation joint equalization is proposed for digital receivers with two samples/symbol or higher sampling rate. Different from traditional methods, the clock recovery algorithm in this paper adopts another algorithm distinguishing the phases of adjacent symbols, so as to accurately estimate the timing offset based on the adjacent signals with the same phase. The addition of the module for eliminating phase modulation interference before timing estimation further reduce the variance, thus resulting in a smoothed timing estimate. The Mean Square Error (MSE) and Bit Error Rate (BER) of the resulting timing estimate are simulated to allow a satisfactory estimation performance. The obtained clock tone performance is satisfactory for MQAM modulation formats and the Roll-off Factor (ROF) close to 0. In the back-to-back system, when ROF= 0, the maximum of MSE obtained with the proposed approach reaches 0 . 0125. After 100-km fiber transmission, BER decreases to 10-3 with ROF= 0 and OSNR = 11 dB. With the increase in ROF, the performances of MSE and BER become better.

Regional-Scale Forcing and Feedbacks from Alternative Scenarios of Global-Scale Land Use Change

NASA Astrophysics Data System (ADS)

Jones, A. D.; Chini, L. P.; Collins, W.; Janetos, A. C.; Mao, J.; Shi, X.; Thomson, A. M.; Torn, M. S.

2011-12-01

Future patterns of land use change depend critically on the degree to which terrestrial carbon management strategies, such as biological carbon sequestration and biofuels, are utilized in order to mitigate global climate change. Furthermore, land use change associated with terrestrial carbon management induces biogeophysical changes to surface energy budgets that perturb climate at regional and possibly global scales, activating different feedback processes depending on the nature and location of the land use change. As a first step in a broader effort to create an integrated earth system model, we examine two scenarios of future anthropogenic activity generated by the Global Change Assessment Model (GCAM) within the full-coupled Community Earth System Model (CESM). Each scenario stabilizes radiative forcing from greenhouse gases and aerosols at 4.5 W/m^2. In the first, stabilization is achieved through a universal carbon tax that values terrestrial carbon equally with fossil carbon, leading to modest afforestation globally and low biofuel utilization. In the second scenario, stabilization is achieved with a tax on fossil fuel and industrial carbon alone. In this case, biofuel utilization increases dramatically and crop area expands to claim approximately 50% of forest cover globally. By design, these scenarios exhibit identical climate forcing from atmospheric constituents. Thus, differences among them can be attributed to the biogeophysical effects of land use change. In addition, we utilize offline radiative transfer and offline land model simulations to identify forcing and feedback mechanisms operating in different regions. We find that boreal deforestation has a strong climatic signature due to significant albedo change coupled with a regional-scale water vapor feedback. Tropical deforestation, on the other hand, has more subtle effects on climate. Globally, the two scenarios yield warming trends over the 21st century that differ by 0.5 degrees Celsius. This work demonstrates the importance of land use in shaping future patterns of climate change, both globally and regionally.

Effect of Social Comparison Feedback on Laboratory Test Ordering for Hospitalized Patients: A Randomized Controlled Trial.

PubMed

Ryskina, Kira; Jessica Dine, C; Gitelman, Yevgeniy; Leri, Damien; Patel, Mitesh; Kurtzman, Gregory; Lin, Lisa Y; Epstein, Andrew J

2018-05-22

Social comparison feedback is an increasingly popular strategy that uses performance report cards to modify physician behavior. Our objective was to test the effect of such feedback on the ordering of routine laboratory tests for hospitalized patients, a practice considered overused. This was a single-blinded randomized controlled trial. Between January and June 2016, physicians on six general medicine teams at the Hospital of the University of Pennsylvania were cluster randomized with equal allocation to two arms: (1) those e-mailed a summary of their routine laboratory test ordering vs. the service average for the prior week, linked to a continuously updated personalized dashboard containing patient-level details, and snapshot of the dashboard and (2) those who did not receive the intervention. The primary outcome was the count of routine laboratory test orders placed by a physician per patient-day. We modeled the count of orders by each physician per patient-day after the intervention as a function of trial arm and the physician's order count before the intervention. The count outcome was modeled using negative binomial models with adjustment for clustering within teams. One hundred and fourteen interns and residents participated. We did not observe a statistically significant difference in adjusted reduction in routine laboratory ordering between the intervention and control physicians (physicians in the intervention group ordered 0.14 fewer tests per patient-day than physicians in the control group, 95% CI - 0.56 to 0.27, p = 0.50). Physicians whose absolute ordering rate deviated from the peer rate by more than 1.0 laboratory test per patient-day reduced their laboratory ordering by 0.80 orders per patient-day (95% CI - 1.58 to - 0.02, p = 0.04). Personalized social comparison feedback on routine laboratory ordering did not change targeted behavior among physicians, although there was a significant decrease in orders among participants who deviated more from the peer rate. Clinicaltrials.gov registration: #NCT02330289.

The Unresponsive Partner: Roles of Social Status, Auditory Feedback, and Animacy in Coordination of Joint Music Performance

PubMed Central

Demos, Alexander P.; Carter, Daniel J.; Wanderley, Marcelo M.; Palmer, Caroline

2017-01-01

We examined temporal synchronization in joint music performance to determine how social status, auditory feedback, and animacy influence interpersonal coordination. A partner’s coordination can be bidirectional (partners adapt to the actions of one another) or unidirectional (one partner adapts). According to the dynamical systems framework, bidirectional coordination should be the optimal (preferred) state during live performance. To test this, 24 skilled pianists each performed with a confederate while their coordination was measured by the asynchrony in their tone onsets. To promote social balance, half of the participants were told the confederate was a fellow participant – an equal social status. To promote social imbalance, the other half was told the confederate was an experimenter – an unequal social status. In all conditions, the confederate’s arm and finger movements were occluded from the participant’s view to allow manipulation of animacy of the confederate’s performances (live or recorded). Unbeknownst to the participants, half of the confederate’s performances were replaced with pre-recordings, forcing the participant into unidirectional coordination during performance. The other half of the confederate’s performances were live, which permitted bidirectional coordination between performers. In a final manipulation, both performers heard the auditory feedback from one or both of the performers’ parts removed at unpredictable times to disrupt their performance. Consistently larger asynchronies were observed in performances of unidirectional (recorded) than bidirectional (live) performances across all conditions. Participants who were told the confederate was an experimenter reported their synchrony as more successful than when the partner was introduced as a fellow participant. Finally, asynchronies increased as auditory feedback was removed; removal of the confederate’s part hurt coordination more than removal of the participant’s part in live performances. Consistent with the assumption that bidirectional coupling yields optimal coordination, an unresponsive partner requires the other member to do all the adapting for the pair to stay together. PMID:28261123

Bioactive trace metal time series during Austral summer in Ryder Bay, Western Antarctic Peninsula

NASA Astrophysics Data System (ADS)

Bown, Johann; Laan, Patrick; Ossebaar, Sharyn; Bakker, Karel; Rozema, Patrick; de Baar, Hein J. W.

2017-05-01

The Western Antarctic Peninsula, one of the most productive regions of the Southern Ocean, is currently affected by the increasing of atmospheric and oceanic temperatures. For several decades, the Rothera Time Series (RaTS) site located in Ryder Bay has been monitored by the British Antarctic Survey and has shown long lasting phytoplankton summer blooms (over a month) that are likely driven by the length of the sea ice season. The dynamics of phytoplankton blooms in Ryder Bay may just as well be influenced by natural fertilization of iron and other bioactive trace metals due to the proximity of land, islands and glaciers. For the first time, temporal distributions in the surface layer (0-75 m depth) of six bioactive trace metals (dissolved: Fe, Mn, Zn, Cd, Cu and dissolved labile Co) have been investigated with high temporal and spatial resolution at the RaTS site during a total of 2 and 3.5 months respectively, over two consecutive summers. Most of the studied trace elements showed wide ranges of concentrations and this dynamics appears to be driven by phytoplankton uptake, remineralization and occasional vertical mixing associated with storm episodes. The biological uptake of DMn, DZn, DCd, DCoL and DCu was proportional to uptake of phosphate and silicate, which was associated with weak to strong linear relationships depending on which phytoplankton bloom events was considered. This further suggests that the surface water distributions of these studied bio-active trace metals were mainly driven by biological uptake and remineralization during austral spring and summer in Ryder Bay. Even though DFe did not show any strong relationship with phosphate, DFe decreasing concentrations during each bloom event suggest that Fe is a key essential element for phytoplankton in the area of study. The consistency of trace metals/nutrient ratios during two consecutive summers indicates that over-winter scavenging removal was slow relative to mixing. The increase of DCd/P and DCoL/P drawdown ratios during the two consecutive blooms monitored during the second season could reflect the substitution of DZn by trace metals DCd and DCoL due to lowered DZn concentrations after the first bloom. Relationships of trace elements versus silicate appear to be dominated by diatoms abundances which tend to vary both at the season and bloom time scale. Simultaneous short-term events of depletions of both nutrients and bio-active trace metals might induce stress in the growth of the phytoplankton assemblage.

CARE AND FEEDING OF FROGS

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

Pan, Margaret; Chiang, Eugene, E-mail: mpan@astro.berkeley.edu

2012-01-15

'Propellers' are features in Saturn's A ring associated with moonlets that open partial gaps. They exhibit non-Keplerian motion (Tiscareno et al.); the longitude residuals of the best-observed propeller, 'Bleriot', appear consistent with a sinusoid of period {approx}4 years. Pan and Chiang proposed that propeller moonlets librate in 'frog resonances' with co-orbiting ring material. By analogy with the restricted three-body problem, they treated the co-orbital material as stationary in the rotating frame and neglected non-co-orbital material. Here we use simple numerical experiments to extend the frog model, including feedback due to the gap's motion, and drag associated with the Lindblad diskmore » torques that cause Type I migration. Because the moonlet creates the gap, we expect the gap centroid to track the moonlet, but only after a time delay t{sub delay}, the time for a ring particle to travel from conjunction with the moonlet to the end of the gap. We find that frog librations can persist only if t{sub delay} exceeds the frog libration period P{sub lib}, and if damping from Lindblad torques balances driving from co-orbital torques. If t{sub delay} << Pl{sub ib}, then the libration amplitude damps to zero. In the case of Bleriot, the frog resonance model can reproduce the observed libration period P{sub lib} {approx_equal} 4 yr. However, our simple feedback prescription suggests that Bleriot's t{sub delay} {approx} 0.01P{sub lib}, which is inconsistent with the observed libration amplitude of 260 km. We urge more accurate treatments of feedback to test the assumptions of our toy models.« less

Feedback-related negativity codes outcome valence, but not outcome expectancy, during reversal learning.

PubMed

von Borries, A K L; Verkes, R J; Bulten, B H; Cools, R; de Bruijn, E R A

2013-12-01

Optimal behavior depends on the ability to assess the predictive value of events and to adjust behavior accordingly. Outcome processing can be studied by using its electrophysiological signatures--that is, the feedback-related negativity (FRN) and the P300. A prominent reinforcement-learning model predicts an FRN on negative prediction errors, as well as implying a role for the FRN in learning and the adaptation of behavior. However, these predictions have recently been challenged. Notably, studies so far have used tasks in which the outcomes have been contingent on the response. In these paradigms, the need to adapt behavioral responses is present only for negative, not for positive feedback. The goal of the present study was to investigate the effects of positive as well as negative violations of expectancy on FRN amplitudes, without the usual confound of behavioral adjustments. A reversal-learning task was employed in which outcome value and outcome expectancy were orthogonalized; that is, both positive and negative outcomes were equally unexpected. The results revealed a double dissociation, with effects of valence but not expectancy on the FRN and, conversely, effects of expectancy but not valence on the P300. While FRN amplitudes were largest for negative-outcome trials, irrespective of outcome expectancy, P300 amplitudes were largest for unexpected-outcome trials, irrespective of outcome valence. These FRN effects were interpreted to reflect an evaluation along a good-bad dimension, rather than reflecting a negative prediction error or a role in behavioral adaptation. By contrast, the P300 reflects the updating of information relevant for behavior in a changing context.

Critical Findings: Attempts at Reducing Notification Errors.

PubMed

Shahriari, Mona; Liu, Li; Yousem, David M

2016-11-01

Ineffective communication of critical findings (CFs) is a patient safety issue. The aim of this study was to assess whether a feedback program for faculty members failing to correctly report CFs would lead to improved compliance. Fifty randomly selected reports were reviewed by the chief of neuroradiology each month for 42 months. Errors included (1) not calling for a CF, (2) not identifying a CF as such, (3) mischaracterizing non-CFs as CFs, and (4) calling for non-CFs. The number of appropriately handled and mishandled reports in each month was recorded. The trend of error reduction after the division chief provided feedback in the subsequent months was evaluated, and the equality of time interval between errors was tested. Among 2,100 reports, 49 (2.3%) were handled inappropriately. Among non-CF reports, 98.97% (1,817 of 1,836) were appropriately not called and not flagged, and 88.64% (234 of 264) of CF reports were called and flagged appropriately. The error rate during the 11th through 32nd months of review (1.28%) was significantly lower than the error rate in the first 10 months of review (3.98%) (P = .001). This benefit lasted for 21 months. Review and giving feedback to radiologists increased their compliance with the CF protocol and decreased deviations from standard operating procedures for about 2 years (from month 10 to month 32). Developing new ideas for improving CF policy compliance may be required at 2- to 3-year intervals to provide continuous quality improvement. Copyright © 2016 American College of Radiology. Published by Elsevier Inc. All rights reserved.

Using Receiver Operating Characteristic Curve to Define the Cutoff Points of Voice Handicap Index Applied to Young Adult Male Smokers.

PubMed

Tafiadis, Dionysios; Chronopoulos, Spyridon K; Kosma, Evangelia I; Voniati, Louiza; Raptis, Vasilis; Siafaka, Vasiliki; Ziavra, Nausica

2017-07-11

Voice performance is an inextricable key factor of everyday life. Obviously, the deterioration of voice quality can cause various problems to human communication and can therefore reduce the performance of social skills (relevant to voice). The deterioration could be originated from changes inside the system of the vocal tract and larynx. Various prognostic methods exist, and among them is the Voice Handicap Index (VHI). This tool includes self-reported questionnaires, used for determining the cutoff points of total score and of its three domains relevant to young male Greek smokers. The interpretation of the calculated cutoff points can serve as a strong indicator of imminent or future evaluation by a clinician. Consistent with previous calculation, the VHI can also act as a feedback for smokers' voice condition and as monitoring procedure toward smoking cessation. Specifically, the sample consisted of 130 male nondysphonic smokers (aged 18-33 years) who all participated in the VHI test procedure. The test results (through receiver operating characteristic analysis) concluded to a total cutoff point score of 19.50 (sensitivity: 0.838, 1-specificity: 0). Also, in terms of constructs, the Functional domain was equal to 7.50 (sensitivity: 0.676, 1-specificity: 0.032), the Physical domain was equal to 7.50 (sensitivity: 0.706, 1-specificity: 0.032), and the Emotional domain was equal to 6.50 (sensitivity: 0.809, 1-specificity: 0.048). Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

Catchments Under Change: Assessing Impacts and Feedbacks from New Biomass Crops in the Agricultural Midwestern USA

NASA Astrophysics Data System (ADS)

Yaeger, Mary; Housh, Mashor; Ng, Tze Ling; Cai, Ximing; Sivapalan, Murugesu

2013-04-01

In order to meet the challenges of future change, it is essential to understand the environmental response to current conditions and historical changes. The central Midwestern US is an example of anthropogenic change and environmental feedbacks, having been transformed from a natural grassland system to an artificially-drained agricultural system. Environmental feedbacks from reduced soil residence times coupled with increasing crop fertilization have manifested as a hypoxic zone in the Gulf of Mexico. In an effort to address these feedbacks while meeting new crop demands, large-scale planting of high-yielding perennial biomass crops has been proposed. This could be detrimental to both human and environmental streamflow users because these plants require more water than do current crops. The lowest natural flows in this shallow groundwater-dependent region coincide with the peak of the growing season, thus compounding the problem. Therefore, for large-scale biomass crop production to be sustainable, these tradeoffs between water quality and water quantity must be fully understood. To better understand the catchment response to current conditions, we have analyzed streamflow data in a central Illinois agricultural watershed. To deal with future changes, we have developed an integrated systems model which provides, among other outputs, the land usage that maximizes the benefit to the human system. This land use is then implemented in a separate hydrologic model to determine the impact to the environmental system. Interactively running the two models, taking into account the catchment response to human actions as well as possible anthropogenic responses to the environment, allows us to examine the feedbacks between the two systems. This lets us plot the trajectory of the state of the system, which we hypothesize will show emergent internal properties of the coupled system. Initial tests of this modeling framework show promise that this may indeed be the case. External economic forcings were applied to the human system, resulting in greatly-reduced streamflow due to a large percentage of the watershed planted with the new crops. The anthropogenic response to this environmental feedback was an imposed minimum flow requirement in the integrated model, which resulted in a new optimized land use that improved environmental conditions, but not to the previous state. Further refinement of this experiment will provide thresholds, both where crop types change, and where environmental damage becomes evident. Preliminary results revealed added complexity, as tributary and mainstem subcatchments do not respond equally, even in this homogenous region; thus the spatial context also becomes important.

A simulation of the intracluster medium with feedback from cluster galaxies

NASA Technical Reports Server (NTRS)

Metzler, Christopher A.; Evrard, August E.

1994-01-01

We detail method and report first results from a three-dimensional hydrodynamical and N-body simulation of the formation and evolution of a Coma-sized cluster of galaxies, with the intent of studying the history of the hot, X-ray emitting intracluster medium. Cluster gas, galaxies, and dark matter are included in the model. The galaxies and dark matter fell gravitational forces; the cluster gas also undergoes hydrodynamical effects such as shock heating and PdV work. For the first time in three dimensions, we include modeling of ejection of processed gas from the simulated galaxies by winds, including heating and heavy element enrichment. For comparison, we employ a `pure infall' simulation using the same initial conditions but with no galaxies or winds. We employ an extreme ejection history for galactic feedback in order to define the boundary of likely models. As expected, feedback raises the entropy of the intracluster gas, preventing it from collapsing to densities as high as those attained in the infall model. The effect is more pronounced in subclusters formed at high redshift. The cluster with feedback is always less X-ray luminous, but experiences more rapid luminosity evolution, than the pure infall cluster. Even employing an extreme ejection model, the final gas temperature is only approximately 15% larger than in the infall model. The radial temperature profile is very nearly isothermal within 1.5 Mpc. The cluster galaxies in the feedback model have a velocity dispersion approximately 15% lower than the dark matter. This results in the true ratio of specific energies in galaxies to gas being less than one, beta(sub spec) approximately 0.7. The infall model predicts beta(sub spec) approximately 1.2. Large excursions in these values occur over time, following the complex dynamical history of the cluster. The morphology of the X-ray emission is little affected by feedback. The emission profiles of both clusters are well described by the standard beta-model with beta(sub fit) approximately equal to 0.7 - 0.9. X-ray mass estimates based on the assumptions of hydrostatic equilibrium and the applicability of the beta-model are quite accurate in both cases. A strong, radial iron abundance gradient is present, which develops as a consequence of the steepening of the galaxy density profile over time. Spectroscopic observations using nonimaging detectors with wide (approximately 45 min) fields of view dramatically smear the gradient. Observations with arcminute resolution, made available with the ASCA satellite, would readily resolve the gradient.

Genetic and demographic implications of aquaculture in white sturgeon (Acipenser transmontanus)conservation

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

Jager, Yetta

2005-01-01

This study uses a genetic individual-based model of white sturgeon (Acipenser transmontanus) populations in a river to examine the genetic and demographic trade-offs associated with operating a conservation hatchery. Simulation experiments evaluated three management practices: (i) setting quotas to equalize family contributions in an effort to prevent genetic swamping, (ii) an adaptive management scheme that interrupts stocking when introgression exceeds a specified threshold, and (iii) alternative broodstock selection strategies that influence domestication. The first set of simulations, designed to evaluate equalizing the genetic contribution of families, did not show the genetic benefits expected. The second set of simulations showed thatmore » simulated adaptive management was not successful in controlling introgression over the long term, especially with uncertain feedback. The third set of simulations compared the effects of three alternative broodstock selection strategies on domestication for hypothetical traits controlling early density-dependent survival. Simulated aquaculture selected for a density-tolerant phenotype when broodstock were taken from a genetically connected population. Using broodstock from an isolated population (i.e., above an upstream barrier or in a different watershed) was more effective at preventing domestication than using wild broodstock from a connected population.« less

A velocity command stepper motor for CSI application

NASA Technical Reports Server (NTRS)

Sulla, Jeffrey L.; Juang, Jer-Nan; Horta, Lucas G.

1991-01-01

The application of linear force actuators for vibration suppression of flexible structures has received much attention in recent years. A linear force actuator consists of a movable mass that is restrained such that its motion is linear. By application of a force to the mass, an equal and opposite reaction force can be applied to a structure. The use of an industrial linear stepper motor as a reaction mass actuator is described. With the linear stepper motor mounted on a simple test beam and the NASA Mini-Mast, output feedback of acceleration or displacement are used to augment the structural damping of the test articles. Significant increases in damping were obtained for both the test beam and the Mini-Mast.

Suppression of Zeeman gradients by nuclear polarization in double quantum dots.

PubMed

Frolov, S M; Danon, J; Nadj-Perge, S; Zuo, K; van Tilburg, J W W; Pribiag, V S; van den Berg, J W G; Bakkers, E P A M; Kouwenhoven, L P

2012-12-07

We use electric dipole spin resonance to measure dynamic nuclear polarization in InAs nanowire quantum dots. The resonance shifts in frequency when the system transitions between metastable high and low current states, indicating the presence of nuclear polarization. We propose that the low and the high current states correspond to different total Zeeman energy gradients between the two quantum dots. In the low current state, dynamic nuclear polarization efficiently compensates the Zeeman gradient due to the g-factor mismatch, resulting in a suppressed total Zeeman gradient. We present a theoretical model of electron-nuclear feedback that demonstrates a fixed point in nuclear polarization for nearly equal Zeeman splittings in the two dots and predicts a narrowed hyperfine gradient distribution.

Ecohydrologic processes and soil thickness feedbacks control limestone-weathering rates in a karst landscape

DOE PAGES

Dong, Xiaoli; Cohen, Matthew J.; Martin, Jonathan B.; ...

2018-05-18

Here, chemical weathering of bedrock plays an essential role in the formation and evolution of Earth's critical zone. Over geologic time, the negative feedback between temperature and chemical weathering rates contributes to the regulation of Earth climate. The challenge of understanding weathering rates and the resulting evolution of critical zone structures lies in complicated interactions and feedbacks among environmental variables, local ecohydrologic processes, and soil thickness, the relative importance of which remains unresolved. We investigate these interactions using a reactive-transport kinetics model, focusing on a low-relief, wetland-dominated karst landscape (Big Cypress National Preserve, South Florida, USA) as a case study.more » Across a broad range of environmental variables, model simulations highlight primary controls of climate and soil biological respiration, where soil thickness both supplies and limits transport of biologically derived acidity. Consequently, the weathering rate maximum occurs at intermediate soil thickness. The value of the maximum weathering rate and the precise soil thickness at which it occurs depend on several environmental variables, including precipitation regime, soil inundation, vegetation characteristics, and rate of groundwater drainage. Simulations for environmental conditions specific to Big Cypress suggest that wetland depressions in this landscape began to form around beginning of the Holocene with gradual dissolution of limestone bedrock and attendant soil development, highlighting large influence of age-varying soil thickness on weathering rates and consequent landscape development. While climatic variables are often considered most important for chemical weathering, our results indicate that soil thickness and biotic activity are equally important. Weathering rates reflect complex interactions among soil thickness, climate, and local hydrologic and biotic processes, which jointly shape the supply and delivery of chemical reactants, and the resulting trajectories of critical zone and karst landscape development.« less

Ecohydrologic processes and soil thickness feedbacks control limestone-weathering rates in a karst landscape

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

Dong, Xiaoli; Cohen, Matthew J.; Martin, Jonathan B.

Here, chemical weathering of bedrock plays an essential role in the formation and evolution of Earth's critical zone. Over geologic time, the negative feedback between temperature and chemical weathering rates contributes to the regulation of Earth climate. The challenge of understanding weathering rates and the resulting evolution of critical zone structures lies in complicated interactions and feedbacks among environmental variables, local ecohydrologic processes, and soil thickness, the relative importance of which remains unresolved. We investigate these interactions using a reactive-transport kinetics model, focusing on a low-relief, wetland-dominated karst landscape (Big Cypress National Preserve, South Florida, USA) as a case study.more » Across a broad range of environmental variables, model simulations highlight primary controls of climate and soil biological respiration, where soil thickness both supplies and limits transport of biologically derived acidity. Consequently, the weathering rate maximum occurs at intermediate soil thickness. The value of the maximum weathering rate and the precise soil thickness at which it occurs depend on several environmental variables, including precipitation regime, soil inundation, vegetation characteristics, and rate of groundwater drainage. Simulations for environmental conditions specific to Big Cypress suggest that wetland depressions in this landscape began to form around beginning of the Holocene with gradual dissolution of limestone bedrock and attendant soil development, highlighting large influence of age-varying soil thickness on weathering rates and consequent landscape development. While climatic variables are often considered most important for chemical weathering, our results indicate that soil thickness and biotic activity are equally important. Weathering rates reflect complex interactions among soil thickness, climate, and local hydrologic and biotic processes, which jointly shape the supply and delivery of chemical reactants, and the resulting trajectories of critical zone and karst landscape development.« less

Quiet eye training in a visuomotor control task.

PubMed

Causer, Joe; Holmes, Paul S; Williams, Andrew Mark

2011-06-01

Several researchers have reported the importance of maintaining a longer final fixation on the target (termed the quiet eye period, QE) before performing an aiming task. We present an innovative, perceptual training intervention intended to improve the efficiency of gaze behavior (i.e., QE) in shotgun shooting. A sample of 20 international-level skeet shooters were assigned equally to one of two ability-matched groups based on their pretest shooting scores. A perceptual training group participated in a four-step preshot routine alongside three video feedback sessions involving their own gaze behaviors and those of an expert model in an effort to positively influence QE behaviors. A control group received video feedback of performance but without the addition of feedback on QE behaviors. Participants completed pretests and posttests along with an 8-wk training intervention. Subjects of the perceptual training group significantly increased their mean QE duration (397 vs 423 ms), used an earlier onset of QE (257 vs 244 ms), and recorded higher shooting accuracy scores (62 vs 70%) from pretest to posttest. Participants in the perceptual training group significantly reduced gun barrel displacement and absolute peak velocity on the posttest compared with the pretest, although neither variable was overtly trained. A transfer test based on performance during competition indicated that perceptual training significantly improved shooting accuracy from before to after the intervention. No pretest to posttest differences were observed for the control group on the measures reported. The results demonstrate the effectiveness of QE training in improving shooting accuracy and developing a more efficient visuomotor control strategy.The findings have implications for future research on training visuomotor behaviors, attention, and gaze orientation during the performance of aiming tasks.

"What did you say?" Using review of tape-recorded interactions to increase social acknowledgments by trainees in a community-based vocational program.

PubMed

Grossi, T A; Kimball, J W; Heward, W L

1994-01-01

Dana and Rick, two adults with developmental disabilities enrolled in a restaurant training program, had poor prospects for long-term employment because of inappropriate social behavior. They often made no response, mumbled inaudibly, or made a negative remark when spoken to by their supervisors or other employees. Each trainee's Individual Vocational Plan (IVP) included goals of prompt and polite acknowledgement of coworker initiations. Previous efforts to improve Dana and Rick's acknowledging behavior had been unsuccessful. Throughout the study, each trainee's responses to 20 verbal initiations by coworkers (i.e., requests, questions, corrective feedback, praise, and social comments) were recorded during each of two observation periods per workshift. Throughout one of the observation periods during the intervention phases, the trainees carried in their work aprons a small, audio cassette recorder that recorded their interactions with coworkers. The primary intervention consisted of a preworkshift meeting in which the trainee and experimenter reviewed five randomly selected interactions recorded during the previous day's shift. The review included self-evaluation, praise, corrective feedback, and role-play. A multiple baseline across subjects design showed each trainee acknowledged a greater number of coworker initiations as a function of the intervention. Each trainee also acknowledged more coworker initiations during the second observation period when the tape recorder was never worn. In a subsequent intervention phase, Dana reviewed her tape-recorded interactions prior to randomly selected shifts. Rick's acknowledgments increased to a socially valid level when the review procedure was supplemented with graphic feedback. Both trainees continued to acknowledge their coworkers' initiations at levels equal to nondisabled restaurant employees when they no longer wore the tape recorder during a final phase and during follow-up observations 4 to 8 weeks later.

Effects of Differential Reinforcement and Rules With Feedback on Preference for Choice and Verbal Reports

PubMed Central

Karsina, Allen; Thompson, Rachel H; Rodriguez, Nicole M; Vanselow, Nicholas R

2012-01-01

We evaluated the effects of differential reinforcement and accurate verbal rules with feedback on the preference for choice and the verbal reports of 6 adults. Participants earned points on a probabilistic schedule by completing the terminal links of a concurrent-chains arrangement in a computer-based game of chance. In free-choice terminal links, participants selected 3 numbers from an 8-number array; in restricted-choice terminal links participants selected the order of 3 numbers preselected by a computer program. A pop-up box then informed the participants if the numbers they selected or ordered matched or did not match numbers generated by the computer but not displayed; matching in a trial resulted in one point earned. In baseline sessions, schedules of reinforcement were equal across free- and restricted-choice arrangements and a running tally of points earned was shown each trial. The effects of differentially reinforcing restricted-choice selections were evaluated using a reversal design. For 4 participants, the effects of providing a running tally of points won by arrangement and verbal rules regarding the schedule of reinforcement were also evaluated using a nonconcurrent multiple-baseline-across-participants design. Results varied across participants but generally demonstrated that (a) preference for choice corresponded more closely to verbal reports of the odds of winning than to reinforcement schedules, (b) rules and feedback were correlated with more accurate verbal reports, and (c) preference for choice corresponded more highly to the relative number of reinforcements obtained across free- and restricted-choice arrangements in a session than to the obtained probability of reinforcement or to verbal reports of the odds of winning. PMID:22754103

Effects of differential reinforcement and rules with feedback on preference for choice and verbal reports.

PubMed

Karsina, Allen; Thompson, Rachel H; Rodriguez, Nicole M; Vanselow, Nicholas R

2012-01-01

We evaluated the effects of differential reinforcement and accurate verbal rules with feedback on the preference for choice and the verbal reports of 6 adults. Participants earned points on a probabilistic schedule by completing the terminal links of a concurrent-chains arrangement in a computer-based game of chance. In free-choice terminal links, participants selected 3 numbers from an 8-number array; in restricted-choice terminal links participants selected the order of 3 numbers preselected by a computer program. A pop-up box then informed the participants if the numbers they selected or ordered matched or did not match numbers generated by the computer but not displayed; matching in a trial resulted in one point earned. In baseline sessions, schedules of reinforcement were equal across free- and restricted-choice arrangements and a running tally of points earned was shown each trial. The effects of differentially reinforcing restricted-choice selections were evaluated using a reversal design. For 4 participants, the effects of providing a running tally of points won by arrangement and verbal rules regarding the schedule of reinforcement were also evaluated using a nonconcurrent multiple-baseline-across-participants design. Results varied across participants but generally demonstrated that (a) preference for choice corresponded more closely to verbal reports of the odds of winning than to reinforcement schedules, (b) rules and feedback were correlated with more accurate verbal reports, and (c) preference for choice corresponded more highly to the relative number of reinforcements obtained across free- and restricted-choice arrangements in a session than to the obtained probability of reinforcement or to verbal reports of the odds of winning.

Early vestibular processing does not discriminate active from passive self-motion if there is a discrepancy between predicted and actual proprioceptive feedback

PubMed Central

Brooks, Jessica X.

2014-01-01

Most of our sensory experiences are gained by active exploration of the world. While the ability to distinguish sensory inputs resulting of our own actions (termed reafference) from those produced externally (termed exafference) is well established, the neural mechanisms underlying this distinction are not fully understood. We have previously proposed that vestibular signals arising from self-generated movements are inhibited by a mechanism that compares the internal prediction of the proprioceptive consequences of self-motion to the actual feedback. Here we directly tested this proposal by recording from single neurons in monkey during vestibular stimulation that was externally produced and/or self-generated. We show for the first time that vestibular reafference is equivalently canceled for self-generated sensory stimulation produced by activation of the neck musculature (head-on-body motion), or axial musculature (combined head and body motion), when there is no discrepancy between the predicted and actual proprioceptive consequences of self-motion. However, if a discrepancy does exist, central vestibular neurons no longer preferentially encode vestibular exafference. Specifically, when simultaneous active and passive motion resulted in activation of the same muscle proprioceptors, neurons robustly encoded the total vestibular input (i.e., responses to vestibular reafference and exafference were equally strong), rather than exafference alone. Taken together, our results show that the cancellation of vestibular reafference in early vestibular processing requires an explicit match between expected and actual proprioceptive feedback. We propose that this vital neuronal computation, necessary for both accurate sensory perception and motor control, has important implications for a variety of sensory systems that suppress self-generated signals. PMID:24671531

Mechanisms and Feedbacks Causing Changes in Upper Stratospheric Ozone in the 21st Century

NASA Technical Reports Server (NTRS)

Oman, Luke; Waugh, D. W.; Kawa, S. R.; Stolarski, R. S.; Douglass, A. R.; Newman, P. A.

2009-01-01

Stratospheric ozone is expected to increase during the 21st century as the abundance of halogenated ozone-depleting substances decrease to 1960 values. However, climate change will likely alter this "recovery" of stratospheric ozone by changing stratospheric temperatures, circulation, and abundance of reactive chemical species. Here we quantity the contribution of different mechanisms to changes in upper stratospheric ozone from 1960 to 2100 in the Goddard Earth Observing System Chemistry-Climate Model (GEOS CCM), using multiple linear regression analysis applied to simulations using either Alb or A2 greenhouse gas (GHG) scenarios. In both these scenarios upper stratospheric ozone has a secular increase over the 21st century. For the simulation using the Alb GHG scenario, this increase is determined by the decrease in halogen amounts and the greenhouse gas induced cooling, with roughly equal contributions from each mechanism. There is a larger cooling in the simulation using the A2 GHG scenario, but also enhanced loss from higher NOy and HOx concentrations, which nearly offsets the increase due to cooler temperatures. The resulting ozone evolutions are similar in the A2 and Alb simulations. The response of ozone due to feedbacks from temperature and HOx changes, related to changing halogen concentrations, are also quantified using simulations with fixed halogen concentrations.

Selecting, training and assessing new general practice community teachers in UK medical schools.

PubMed

Hydes, Ciaran; Ajjawi, Rola

2015-09-01

Standards for undergraduate medical education in the UK, published in Tomorrow's Doctors, include the criterion 'everyone involved in educating medical students will be appropriately selected, trained, supported and appraised'. To establish how new general practice (GP) community teachers of medical students are selected, initially trained and assessed by UK medical schools and establish the extent to which Tomorrow's Doctors standards are being met. A mixed-methods study with questionnaire data collected from 24 lead GPs at UK medical schools, 23 new GP teachers from two medical schools plus a semi-structured telephone interview with two GP leads. Quantitative data were analysed descriptively and qualitative data were analysed informed by framework analysis. GP teachers' selection is non-standardised. One hundred per cent of GP leads provide initial training courses for new GP teachers; 50% are mandatory. The content and length of courses varies. All GP leads use student feedback to assess teaching, but other required methods (peer review and patient feedback) are not universally used. To meet General Medical Council standards, medical schools need to include equality and diversity in initial training and use more than one method to assess new GP teachers. Wider debate about the selection, training and assessment of new GP teachers is needed to agree minimum standards.

The efficacy of video feedback for learning the golf swing.

PubMed

Guadagnoli, M; Holcomb, W; Davis, M

2002-08-01

This study was designed to examine the efficacy of video instruction relative to that of verbal and self-guided instruction. Before training, 30 golfers were assigned at random to one of three groups: video, verbal or self-guided instruction. Video instruction was defined as a practice session in which the teacher was aided by the use of video. Verbal instruction was defined as practising with the teacher providing verbal feedback. Self-guided practice was defined as practising without the aid of a teacher. The participants had a pre-test, four 90 min practice sessions, an immediate post-test and a 2 week delayed post-test. During the pre-test and post-tests, all participants were required to strike 15 golf balls, with a 7-iron, from an artificial turf mat for distance and accuracy. The results showed that all groups were equal on the pre-test. On the first post-test, the two instruction groups performed worse than the self-guided group. However, on the second post-test, the two instruction groups performed better than the self-guided group, with the video group performing best. We interpret these results to mean that video analysis is an effective means of practice, but that the positive effects may take some time to develop.

Virtual Active Touch Using Randomly Patterned Intracortical Microstimulation

PubMed Central

O’Doherty, Joseph E.; Lebedev, Mikhail A.; Li, Zheng; Nicolelis, Miguel A.L.

2012-01-01

Intracortical microstimulation (ICMS) has promise as a means for delivering somatosensory feedback in neuroprosthetic systems. Various tactile sensations could be encoded by temporal, spatial, or spatiotemporal patterns of ICMS. However, the applicability of temporal patterns of ICMS to artificial tactile sensation during active exploration is unknown, as is the minimum discriminable difference between temporally modulated ICMS patterns. We trained rhesus monkeys in an active exploration task in which they discriminated periodic pulse-trains of ICMS (200 Hz bursts at a 10 Hz secondary frequency) from pulse trains with the same average pulse rate, but distorted periodicity (200 Hz bursts at a variable instantaneous secondary frequency). The statistics of the aperiodic pulse trains were drawn from a gamma distribution with mean inter-burst intervals equal to those of the periodic pulse trains. The monkeys distinguished periodic pulse trains from aperiodic pulse trains with coefficients of variation 0.25 or greater. Reconstruction of movement kinematics, extracted from the activity of neuronal populations recorded in the sensorimotor cortex concurrent with the delivery of ICMS feedback, improved when the recording intervals affected by ICMS artifacts were removed from analysis. These results add to the growing evidence that temporally patterned ICMS can be used to simulate a tactile sense for neuroprosthetic devices. PMID:22207642

Interplay of bistable kinetics of gene expression during cellular growth

NASA Astrophysics Data System (ADS)

Zhdanov, Vladimir P.

2009-02-01

In cells, the bistable kinetics of gene expression can be observed on the level of (i) one gene with positive feedback between protein and mRNA production, (ii) two genes with negative mutual feedback between protein and mRNA production, or (iii) in more complex cases. We analyse the interplay of two genes of type (ii) governed by a gene of type (i) during cellular growth. In particular, using kinetic Monte Carlo simulations, we show that in the case where gene 1, operating in the bistable regime, regulates mutually inhibiting genes 2 and 3, also operating in the bistable regime, the latter genes may eventually be trapped either to the state with high transcriptional activity of gene 2 and low activity of gene 3 or to the state with high transcriptional activity of gene 3 and low activity of gene 2. The probability to get to one of these states depends on the values of the model parameters. If genes 2 and 3 are kinetically equivalent, the probability is equal to 0.5. Thus, our model illustrates how different intracellular states can be chosen at random with predetermined probabilities. This type of kinetics of gene expression may be behind complex processes occurring in cells, e.g., behind the choice of the fate by stem cells.

A COMPARATIVE STUDY OF EFFICACY OF EMG BIO-FEEDBACK AND PROGRESSIVE MUSCULAR RELAXATION IN TENSION HEADACHE1

PubMed Central

Gada, M.T.

1984-01-01

SUMMARY The aim of the present study was to find out efficacy of frontalis EMG Biofeedback therapy, deep muscular relaxation therapy and compare the efficacy of both in cases of tension headache. During two week basal-data recording period all patients were taught deep muscular relaxation by Jacobson′s technique. Simultaneously patients were instructed to keep headache diary. Headache diary yielded three different parameters a) number of headache-free days per week, b) peak headache intensity (or each week and c) average daily headache activity score per week. These parameters were used to find out therapeutic efficacy of each treatment. Patients were randomly divided in two groups. EMG Biofeedback group was given frontalis EMG feedback through EMG J 33 muscle trainer of Cyborg Corporation (U.S.A.). Patients in each group were given 20 sessions (two sessions per week); each session lasting 30 minutes. Patients were instructed to practice at least one 30 minute session of relaxation at home. The data were subjected to statistical calculation. The results indicate that frontalis EMG Biofeedback therapy and deep muscle relaxation therapy are significantly effective in cases of tension headache. Both treatments are equally effective. The findings are discussed in relation to Indian situation. PMID:21965970

Informationally administered reward enhances intrinsic motivation in schizophrenia.

PubMed

Lee, Hyeon-Seung; Jang, Seon-Kyeong; Lee, Ga-Young; Park, Seon-Cheol; Medalia, Alice; Choi, Kee-Hong

2017-10-01

Even when individuals with schizophrenia have an intact ability to enjoy rewarding moments, the means to assist them to translate rewarding experiences into goal-directed behaviors is unclear. The present study sought to determine whether informationally administered rewards enhance intrinsic motivation to foster goal-directed behaviors in individuals with schizophrenia (SZ) and healthy controls (HCs). Eighty-four participants (SZ=43, HCs=41) were randomly assigned to conditions involving either a performance-contingent reward with an informationally administered reward or a task-contingent reward with no feedback. Participants were asked to play two cognitive games of equalized difficulty. Accuracy, self-reported intrinsic motivation, free-choice intrinsic motivation (i.e., game play during a free-choice observation period), and perceived competency were measured. Intrinsic motivation and perceived competency in the cognitive games were similar between the two participant groups. The informationally administered reward significantly enhanced self-reported intrinsic motivation and perceived competency in both the groups. The likelihood that individuals with schizophrenia would play the game during the free-choice observation period was four times greater in the informationally administered reward condition than that in the no-feedback condition. Our findings suggest that, in the context of cognitive remediation, individuals with schizophrenia would benefit from informationally administered rewards. Copyright © 2017 Elsevier B.V. All rights reserved.

The Dolinar Receiver in an Information Theoretic Framework

NASA Technical Reports Server (NTRS)

Erkmen, Baris I.; Birnbaum, Kevin M.; Moision, Bruce E.; Dolinar, Samuel J.

2011-01-01

Optical communication at the quantum limit requires that measurements on the optical field be maximally informative, but devising physical measurements that accomplish this objective has proven challenging. The Dolinar receiver exemplifies a rare instance of success in distinguishing between two coherent states: an adaptive local oscillator is mixed with the signal prior to photodetection, which yields an error probability that meets the Helstrom lower bound with equality. Here we apply the same local-oscillator-based architecture with aninformation-theoretic optimization criterion. We begin with analysis of this receiver in a general framework for an arbitrary coherent-state modulation alphabet, and then we concentrate on two relevant examples. First, we study a binary antipodal alphabet and show that the Dolinar receiver's feedback function not only minimizes the probability of error, but also maximizes the mutual information. Next, we study ternary modulation consistingof antipodal coherent states and the vacuum state. We derive an analytic expression for a near-optimal local oscillator feedback function, and, via simulation, we determine its photon information efficiency (PIE). We provide the PIE versus dimensional information efficiency (DIE) trade-off curve and show that this modulation and the our receiver combination performs universally better than (generalized) on-off keying plus photoncounting, although, the advantage asymptotically vanishes as the bits-per-photon diverges towards infinity.

Forback DC-to-DC converter

NASA Technical Reports Server (NTRS)

Lukemire, Alan T. (Inventor)

1995-01-01

A pulse-width modulated DC-to-DC power converter including a first inductor, i.e. a transformer or an equivalent fixed inductor equal to the inductance of the secondary winding of the transformer, coupled across a source of DC input voltage via a transistor switch which is rendered alternately conductive (ON) and nonconductive (OFF) in accordance with a signal from a feedback control circuit is described. A first capacitor capacitively couples one side of the first inductor to a second inductor which is connected to a second capacitor which is coupled to the other side of the first inductor. A circuit load shunts the second capacitor. A semiconductor diode is additionally coupled from a common circuit connection between the first capacitor and the second inductor to the other side of the first inductor. A current sense transformer generating a current feedback signal for the switch control circuit is directly coupled in series with the other side of the first inductor so that the first capacitor, the second inductor and the current sense transformer are connected in series through the first inductor. The inductance values of the first and second inductors, moreover, are made identical. Such a converter topology results in a simultaneous voltsecond balance in the first inductance and ampere-second balance in the current sense transformer.

Modelling landslide liquefaction, mobility bifurcation and the dynamics of the 2014 Oso disaster

USGS Publications Warehouse

Iverson, Richard M.; George, David L.

2016-01-01

Some landslides move slowly or intermittently downslope, but others liquefy during the early stages of motion, leading to runaway acceleration and high-speed runout across low-relief terrain. Mechanisms responsible for this disparate behaviour are represented in a two-phase, depth-integrated, landslide dynamics model that melds principles from soil mechanics, granular mechanics and fluid mechanics. The model assumes that gradually increasing pore-water pressure causes slope failure to nucleate at the weakest point on a basal slip surface in a statically balanced mass. Failure then spreads to adjacent regions as a result of momentum exchange. Liquefaction is contingent on pore-pressure feedback that depends on the initial soil state. The importance of this feedback is illustrated by using the model to study the dynamics of a disastrous landslide that occurred near Oso, Washington, USA, on 22 March 2014. Alternative simulations of the event reveal the pronounced effects of a landslide mobility bifurcation that occurs if the initial void ratio of water-saturated soil equals the lithostatic, critical-state void ratio. They also show that the tendency for bifurcation increases as the soil permeability decreases. The bifurcation implies that it can be difficult to discriminate conditions that favour slow landsliding from those that favour liquefaction and long runout.

AGN jet-driven stochastic cold accretion in cluster cores

NASA Astrophysics Data System (ADS)

Prasad, Deovrat; Sharma, Prateek; Babul, Arif

2017-10-01

Several arguments suggest that stochastic condensation of cold gas and its accretion on to the central supermassive black hole (SMBH) is essential for active galactic nuclei (AGNs) feedback to work in the most massive galaxies that lie at the centres of galaxy clusters. Our 3-D hydrodynamic AGN jet-ICM (intracluster medium) simulations, looking at the detailed angular momentum distribution of cold gas and its time variability for the first time, show that the angular momentum of the cold gas crossing ≲1 kpc is essentially isotropic. With almost equal mass in clockwise and counterclockwise orientations, we expect a cancellation of the angular momentum on roughly the dynamical time. This means that a compact accretion flow with a short viscous time ought to form, through which enough accretion power can be channeled into jet mechanical energy sufficiently quickly to prevent a cooling flow. The inherent stochasticity, expected in feedback cycles driven by cold gas condensation, gives rise to a large variation in the cold gas mass at the centres of galaxy clusters, for similar cluster and SMBH masses, in agreement with the observations. Such correlations are expected to be much tighter for the smoother hot/Bondi accretion. The weak correlation between cavity power and Bondi power obtained from our simulations also matches observations.

AN INTERNET RACK MONITOR-CONTROLLER FOR APS LINAC RF ELECTRONICS UPGRADE

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

Ma, Hengjie; Smith, Terry; Nassiri, Alireza

To support the research and development in APS LINAC area, the existing LINAC rf control performance needs to be much improved, and thus an upgrade of the legacy LINAC rf electronics becomes necessary. The proposed upgrade plan centers on the concept of using a modern, network-attached, rackmount digital electronics platform –Internet Rack Monitor-Controller (or IRMC) to achieve the goal of modernizing the rf electronics at a lower cost. The system model of the envisioned IRMC is basically a 3-tier stack with a high-performance DSP in the mid-layer to perform the core tasks of real-time rf data processing and controls. Themore » Digital Front-End (DFE) attachment layer at bottom bridges the applicationspecific rf front-ends to the DSP. A network communication gateway, together with an embedded event receiver (EVR) in the top layer merges the Internet Rack MonitorController node into the networks of the accelerator controls infrastructure. Although the concept is very much in trend with today’s Internet-of-Things (IoT), this implementation has actually been used in the accelerators for over two decades.« less

A randomised trial of the influence of racial stereotype bias on examiners' scores, feedback and recollections in undergraduate clinical exams.

PubMed

Yeates, Peter; Woolf, Katherine; Benbow, Emyr; Davies, Ben; Boohan, Mairhead; Eva, Kevin

2017-10-25

Asian medical students and doctors receive lower scores on average than their white counterparts in examinations in the UK and internationally (a phenomenon known as "differential attainment"). This could be due to examiner bias or to social, psychological or cultural influences on learning or performance. We investigated whether students' scores or feedback show influence of ethnicity-related bias; whether examiners unconsciously bring to mind (activate) stereotypes when judging Asian students' performance; whether activation depends on the stereotypicality of students' performances; and whether stereotypes influence examiner memories of performances. This is a randomised, double-blinded, controlled, Internet-based trial. We created near-identical videos of medical student performances on a simulated Objective Structured Clinical Exam using British Asian and white British actors. Examiners were randomly assigned to watch performances from white and Asian students that were either consistent or inconsistent with a previously described stereotype of Asian students' performance. We compared the two examiner groups in terms of the following: the scores and feedback they gave white and Asian students; how much the Asian stereotype was activated in their minds (response times to Asian-stereotypical vs neutral words in a lexical decision task); and whether the stereotype influenced memories of student performances (recognition rates for real vs invented stereotype-consistent vs stereotype-inconsistent phrases from one of the videos). Examiners responded to Asian-stereotypical words (716 ms, 95% confidence interval (CI) 702-731 ms) faster than neutral words (769 ms, 95% CI 753-786 ms, p < 0.001), suggesting Asian stereotypes were activated (or at least active) in examiners' minds. This occurred regardless of whether examiners observed stereotype-consistent or stereotype-inconsistent performances. Despite this stereotype activation, student ethnicity had no influence on examiners' scores; on the feedback examiners gave; or on examiners' memories for one performance. Examiner bias does not appear to explain the differential attainment of Asian students in UK medical schools. Efforts to ensure equality should focus on social, psychological and cultural factors that may disadvantage learning or performance in Asian and other minority ethnic students.

A spherical model for orientation and spatial-frequency tuning in a cortical hypercolumn.

PubMed Central

Bressloff, Paul C; Cowan, Jack D

2003-01-01

A theory is presented of the way in which the hypercolumns in primary visual cortex (V1) are organized to detect important features of visual images, namely local orientation and spatial-frequency. Given the existence in V1 of dual maps for these features, both organized around orientation pinwheels, we constructed a model of a hypercolumn in which orientation and spatial-frequency preferences are represented by the two angular coordinates of a sphere. The two poles of this sphere are taken to correspond, respectively, to high and low spatial-frequency preferences. In Part I of the paper, we use mean-field methods to derive exact solutions for localized activity states on the sphere. We show how cortical amplification through recurrent interactions generates a sharply tuned, contrast-invariant population response to both local orientation and local spatial frequency, even in the case of a weakly biased input from the lateral geniculate nucleus (LGN). A major prediction of our model is that this response is non-separable with respect to the local orientation and spatial frequency of a stimulus. That is, orientation tuning is weaker around the pinwheels, and there is a shift in spatial-frequency tuning towards that of the closest pinwheel at non-optimal orientations. In Part II of the paper, we demonstrate that a simple feed-forward model of spatial-frequency preference, unlike that for orientation preference, does not generate a faithful representation when amplified by recurrent interactions in V1. We then introduce the idea that cortico-geniculate feedback modulates LGN activity to generate a faithful representation, thus providing a new functional interpretation of the role of this feedback pathway. Using linear filter theory, we show that if the feedback from a cortical cell is taken to be approximately equal to the reciprocal of the corresponding feed-forward receptive field (in the two-dimensional Fourier domain), then the mismatch between the feed-forward and cortical frequency representations is eliminated. We therefore predict that cortico-geniculate feedback connections innervate the LGN in a pattern determined by the orientation and spatial-frequency biases of feed-forward receptive fields. Finally, we show how recurrent cortical interactions can generate cross-orientation suppression. PMID:14561324

The influence of ice sheets on temperature during the past 38 million years inferred from a one-dimensional ice sheet-climate model

NASA Astrophysics Data System (ADS)

Stap, Lennert B.; van de Wal, Roderik S. W.; de Boer, Bas; Bintanja, Richard; Lourens, Lucas J.

2017-09-01

Since the inception of the Antarctic ice sheet at the Eocene-Oligocene transition (˜ 34 Myr ago), land ice has played a crucial role in Earth's climate. Through feedbacks in the climate system, land ice variability modifies atmospheric temperature changes induced by orbital, topographical, and greenhouse gas variations. Quantification of these feedbacks on long timescales has hitherto scarcely been undertaken. In this study, we use a zonally averaged energy balance climate model bidirectionally coupled to a one-dimensional ice sheet model, capturing the ice-albedo and surface-height-temperature feedbacks. Potentially important transient changes in topographic boundary conditions by tectonics and erosion are not taken into account but are briefly discussed. The relative simplicity of the coupled model allows us to perform integrations over the past 38 Myr in a fully transient fashion using a benthic oxygen isotope record as forcing to inversely simulate CO2. Firstly, we find that the results of the simulations over the past 5 Myr are dependent on whether the model run is started at 5 or 38 Myr ago. This is because the relation between CO2 and temperature is subject to hysteresis. When the climate cools from very high CO2 levels, as in the longer transient 38 Myr run, temperatures in the lower CO2 range of the past 5 Myr are higher than when the climate is initialised at low temperatures. Consequently, the modelled CO2 concentrations depend on the initial state. Taking the realistic warm initialisation into account, we come to a best estimate of CO2, temperature, ice-volume-equivalent sea level, and benthic δ18O over the past 38 Myr. Secondly, we study the influence of ice sheets on the evolution of global temperature and polar amplification by comparing runs with ice sheet-climate interaction switched on and off. By passing only albedo or surface height changes to the climate model, we can distinguish the separate effects of the ice-albedo and surface-height-temperature feedbacks. We find that ice volume variability has a strong enhancing effect on atmospheric temperature changes, particularly in the regions where the ice sheets are located. As a result, polar amplification in the Northern Hemisphere decreases towards warmer climates as there is little land ice left to melt. Conversely, decay of the Antarctic ice sheet increases polar amplification in the Southern Hemisphere in the high-CO2 regime. Our results also show that in cooler climates than the pre-industrial, the ice-albedo feedback predominates the surface-height-temperature feedback, while in warmer climates they are more equal in strength.

3D-FE Modeling of 316 SS under Strain-Controlled Fatigue Loading and CFD Simulation of PWR Surge Line

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

Mohanty, Subhasish; Barua, Bipul; Listwan, Joseph

In financial year 2017, we are focusing on developing a mechanistic fatigue model of surge line pipes for pressurized water reactors (PWRs). To that end, we plan to perform the following tasks: (1) conduct stress- and strain-controlled fatigue testing of surge-line base metal such as 316 stainless steel (SS) under constant, variable, and random fatigue loading, (2) develop cyclic plasticity material models of 316 SS, (3) develop one-dimensional (1D) analytical or closed-form model to validate the material models and to understand the mechanics associated with 316 SS cyclic hardening and/or softening, (4) develop three-dimensional (3D) finite element (FE) models withmore » implementation of evolutionary cyclic plasticity, and (5) develop computational fluid dynamics (CFD) model for thermal stratification, thermal-mechanical stress, and fatigue of example reactor components, such as a PWR surge line under plant heat-up, cool-down, and normal operation with/without grid-load-following. This semi-annual progress report presents the work completed on the above tasks for a 316 SS laboratory-scale specimen subjected to strain-controlled cyclic loading with constant, variable, and random amplitude. This is the first time that the accurate 3D-FE modeling of the specimen for its entire fatigue life, including the hardening and softening behavior, has been achieved. We anticipate that this work will pave the way for the development of a fully mechanistic-computer model that can be used for fatigue evaluation of safety-critical metallic components, which are traditionally evaluated by heavy reliance on time-consuming and costly test-based approaches. This basic research will not only help the nuclear reactor industry for fatigue evaluation of reactor components in a cost effective and less time-consuming way, but will also help other safety-related industries, such as aerospace, which is heavily dependent on test-based approaches, where a single full-scale fatigue test can cost millions of dollars and require years of effort to conduct. Toward our goal of demonstration of fully mechanistic fatigue evaluation of reactor components, we also started work on developing a component-level computer model of reactor components, such as 316 SS surge line pipe. This requires developing a thermal-mechanical stress analysis model of the reactor surge line, which, in turn, requires time-dependent temperature and stratification information along the boundary of the pipe. Toward that goal, CFD models of surge lines are being developed. In this report, we also present some preliminary results showing the temperature conditions along the surge line wall under reactor heat-up, cool-down, and steady-state power operation.« less

Context dependent prediction and category encoding for DPCM image compression

NASA Technical Reports Server (NTRS)

Beaudet, Paul R.

1989-01-01

Efficient compression of image data requires the understanding of the noise characteristics of sensors as well as the redundancy expected in imagery. Herein, the techniques of Differential Pulse Code Modulation (DPCM) are reviewed and modified for information-preserving data compression. The modifications include: mapping from intensity to an equal variance space; context dependent one and two dimensional predictors; rationale for nonlinear DPCM encoding based upon an image quality model; context dependent variable length encoding of 2x2 data blocks; and feedback control for constant output rate systems. Examples are presented at compression rates between 1.3 and 2.8 bits per pixel. The need for larger block sizes, 2D context dependent predictors, and the hope for sub-bits-per-pixel compression which maintains spacial resolution (information preserving) are discussed.

Multimode four-wave mixing in an unresolved sideband optomechanical system

NASA Astrophysics Data System (ADS)

Li, Zongyang; You, Xiang; Li, Yongmin; Liu, Yong-Chun; Peng, Kunchi

2018-03-01

We have studied multimode four-wave mixing (FWM) in an unresolved sideband cavity optomechanical system. The radiation pressure coupling between the cavity fields and multiple mechanical modes results in the formation of a series of tripod-type energy-level systems, which induce the multimode FWM phenomenon. The FWM mechanism enables remarkable amplification of a weak signal field accompanied by the generation of an FWM field when only a microwatt-level pump field is applied. For proper system parameters, the amplified signal and FWM fields have equal intensity with opposite phases. The gain and frequency response bandwidth of the signal field can be dynamically tuned by varying the pump intensity, optomechanical coupling strength, and additional feedback control. Under certain conditions, the frequency response bandwidth can be very narrow and reaches the level of hertz.

Collective induction without cooperation? Learning and knowledge transfer in cooperative groups and competitive auctions.

PubMed

Maciejovsky, Boris; Budescu, David V

2007-05-01

There is strong evidence that groups perform better than individuals do on intellective tasks with demonstrably correct solutions. Typically, these studies assume that group members share common goals. The authors extend this line of research by replacing standard face-to-face group interactions with competitive auctions, allowing for conflicting individual incentives. In a series of studies involving the well-known Wason selection task, they demonstrate that competitive auctions induce learning effects equally impressive as those of standard group interactions, and they uncover specific and general knowledge transfers from these institutions to new reasoning problems. The authors identify payoff feedback and information pooling as the driving factors underlying these findings, and they explain these factors within the theoretical framework of collective induction. ((c) 2007 APA, all rights reserved).

LOGARITHMIC AMPLIFIER

DOEpatents

De Shong, J.A. Jr.

1957-12-31

A logarithmic current amplifier circuit having a high sensitivity and fast response is described. The inventor discovered the time constant of the input circuit of a system utilizing a feedback amplifier, ionization chamber, and a diode, is inversely proportional to the input current, and that the amplifier becomes unstable in amplifying signals in the upper frequency range when the amplifier's forward gain time constant equals the input circuit time constant. The described device incorporates impedance networks having low frequency response characteristic at various points in the circuit to change the forward gain of the amplifler at a rate of 0.7 of the gain magnitude for every two times increased in frequency. As a result of this improvement, the time constant of the input circuit is greatly reduced at high frequencies, and the amplifier response is increased.

Linewidth-tolerant 10-Gbit/s 16-QAM transmission using a pilot-carrier based phase-noise cancelling technique.

PubMed

Nakamura, Moriya; Kamio, Yukiyoshi; Miyazaki, Tetsuya

2008-07-07

We experimentally demonstrated linewidth-tolerant 10-Gbit/s (2.5-Gsymbol/s) 16-quadrature amplitude modulation (QAM) by using a distributed-feedback laser diode (DFB-LD) with a linewidth of 30 MHz. Error-free operation, a bit-error rate (BER) of <10(-9) was achieved in transmission over 120 km of standard single mode fiber (SSMF) without any dispersion compensation. The phase-noise canceling capability provided by a pilot-carrier and standard electronic pre-equalization to suppress inter-symbol interference (ISI) gave clear 16-QAM constellations and floor-less BER characteristics. We evaluated the BER characteristics by real-time measurement of six (three different thresholds for each I- and Q-component) symbol error rates (SERs) with simultaneous constellation observation.

Primary percutaneous coronary intervention for patients presenting with ST-segment elevation myocardial infarction: process improvement in a rural ST-segment elevation myocardial infarction receiving center.

PubMed

Niles, Nathaniel W; Conley, Sheila M; Yang, Rayson C; Vanichakarn, Pantila; Anderson, Tamara A; Butterly, John R; Robb, John F; Jayne, John E; Yanofsky, Norman N; Proehl, Jean A; Guadagni, Donald F; Brown, Jeremiah R

2010-01-01

Rural ST-segment elevation myocardial infarction (STEMI) care networks may be particularly disadvantaged in achieving a door-to-balloon time (D2B) of less than or equal to 90 minutes recommended in current guidelines. ST-ELEVATION MYOCARDIAL INFARCTION PROCESS UPGRADE PROJECT: A multidisciplinary STEMI process upgrade group at a rural percutaneous coronary intervention center implemented evidence-based strategies to reduce time to electrocardiogram (ECG) and D2B, including catheterization laboratory activation triggered by either a prehospital ECG demonstrating STEMI or an emergency department physician diagnosing STEMI, single-call catheterization laboratory activation, catheterization laboratory response time less than or equal to 30 minutes, and prompt data feedback. An ongoing regional STEMI registry was used to collect process time intervals, including time to ECG and D2B, in a consecutive series of STEMI patients presenting before (group 1) and after (group 2) strategy implementation. Significant reductions in time to first ECG in the emergency department and D2B were seen in group 2 compared with group 1. Important improvement in the process of acute STEMI patient care was accomplished in the rural percutaneous coronary intervention center setting by implementing evidence-based strategies. Copyright © 2010 Elsevier Inc. All rights reserved.

Dependence of diffusive radiative transfer on grain-size, temperature, and Fe-content: Implications for mantle processes

NASA Astrophysics Data System (ADS)

Hofmeister, A. M.

2005-08-01

Locally diffusive, radiative heat transport inside the earth is represented by an effective thermal conductivity ( krad,dif), calculated from spectra. Previous geophysical models assumed that emissivity ( ξ) equals unity, which violates local radiative equilibrium in an internally heated, grainy medium. Our new formulation accounts for ξ depending on frequency, physical scattering depending on grain-size ( d), and for light lost through back-reflections at interfaces. Mantle values of krad,dif are estimated from recent visible spectra of olivine combined with new IR data. The following trends hold for krad,dif calculated from olivine spectra, and should be equally valid for pyroxene and spinel: (1) pressure is unimportant, (2) radiative thermal conductivity depends non-linearly on d, temperature ( T), and Fe 2+ content ( X), (3) maxima occur in krad,dif( d) when the grains are large enough to emit substantially, but not so large that light is strongly attenuated within a single-grain, (4) the dependence of krad,dif on Fe 2+ content parallels that with d because absorption is controlled by the product dX (Beer's law), and (5) a local minimum occurs in krad,dif near 2000 K for d > 2 mm because at that temperature the peak position of the blackbody curve coincides with that of the strongly absorbing Fe 2+ peak in the visible. Larger krad,dif exists at lower and higher temperatures because mean free paths are long in the transmitting near-IR and UV spectral regions. As integration smooths over spectral details, the above representation based on olivine becomes increasingly accurate for other phases as grain-size decreases. For conditions expected in the transition zone, ∂ krad,dif/∂ T is negative, which is destabilizing [Dubuffet, F., Yuen, D.A., Rainey, E.S.G., 2002. Controlling thermal chaos in the mantle by positive feedback from radiative thermal conductivity. Nonlinear Proc. Geophys. 9, 1-13]. In the lower mantle, photon transport dominates phonon, promoting stable, weak convection. That radiative transfer is linked to chemical composition and grain-size suggests that this process impacts planetary evolution through the non-linear feedback with rheology.

Analysis of biochemical phase shift oscillators by a harmonic balancing technique.

PubMed

Rapp, P

1976-11-25

The use of harmonic balancing techniques for theoretically investigating a large class of biochemical phase shift oscillators is outlined and the accuracy of this approximate technique for large dimension nonlinear chemical systems is considered. It is concluded that for the equations under study these techniques can be successfully employed to both find periodic solutions and to indicate those cases which can not oscillate. The technique is a general one and it is possible to state a step by step procedure for its application. It has a substantial advantage in producing results which are immediately valid for arbitrary dimension. As the accuracy of the method increases with dimension, it complements classical small dimension methods. The results obtained by harmonic balancing analysis are compared with those obtained by studying the local stability properties of the singular points of the differential equation. A general theorem is derived which identifies those special cases where the results of first order harmonic balancing are identical to those of local stability analysis, and a necessary condition for this equivalence is derived. As a concrete example, the n-dimensional Goodwin oscillator is considered where p, the Hill coefficient of the feedback metabolite, is equal to three and four. It is shown that for p = 3 or 4 and n less than or equal to 4 the approximation indicates that it is impossible to construct a set of physically permissible reaction constants such that the system possesses a periodic solution. However for n greater than or equal to 5 it is always possible to find a large domain in the reaction constant space giving stable oscillations. A means of constructing such a parameter set is given. The results obtained here are compared with previously derived results for p = 1 and p = 2.

Conical Euler simulation and active suppression of delta wing rocking motion

NASA Technical Reports Server (NTRS)

Lee, Elizabeth M.; Batina, John T.

1990-01-01

A conical Euler code was developed to study unsteady vortex-dominated flows about rolling highly-swept delta wings, undergoing either forced or free-to-roll motions including active roll suppression. The flow solver of the code involves a multistage Runge-Kutta time-stepping scheme which uses a finite volume spatial discretization of the Euler equations on an unstructured grid of triangles. The code allows for the additional analysis of the free-to-roll case, by including the rigid-body equation of motion for its simultaneous time integration with the governing flow equations. Results are presented for a 75 deg swept sharp leading edge delta wing at a freestream Mach number of 1.2 and at alpha equal to 10 and 30 deg angle of attack. A forced harmonic analysis indicates that the rolling moment coefficient provides: (1) a positive damping at the lower angle of attack equal to 10 deg, which is verified in a free-to-roll calculation; (2) a negative damping at the higher angle of attack equal to 30 deg at the small roll amplitudes. A free-to-roll calculation for the latter case produces an initially divergent response, but as the amplitude of motion grows with time, the response transitions to a wing-rock type of limit cycle oscillation. The wing rocking motion may be actively suppressed, however, through the use of a rate-feedback control law and antisymmetrically deflected leading edge flaps. The descriptions of the conical Euler flow solver and the free-to-roll analysis are presented. Results are also presented which give insight into the flow physics associated with unsteady vortical flows about forced and free-to-roll delta wings, including the active roll suppression of this wing-rock phenomenon.

Load balancing and closed chain multiple arm control

NASA Technical Reports Server (NTRS)

Kreutz, Kenneth; Lokshin, Anatole

1988-01-01

The authors give the general dynamical equations for several rigid link manipulators rigidly grasping a commonly held rigid object. It is shown that the number of arm-configuration degrees of freedom lost due to imposing the closed-loop kinematic constraints is the same as the number of degrees of freedom gained for controlling the internal forces of the closed-chain system. This number is equal to the dimension of the kernel of the Jacobian operator which transforms contact forces to the net forces acting on the held object, and it is shown that this kernel can be identified with the subspace of controllable internal forces of the closed-chain system. Control of these forces makes it possible to regulate the grasping forces imparted to the held object or to control the load taken by each arm. It is shown that the internal forces can be influenced without affecting the control of the configuration degrees of freedom. Control laws of the feedback linearization type are shown to be useful for controlling the location and attitude of a frame fixed with respect to the held object, while simultaneously controlling the internal forces of the closed-chain system. Force feedback can be used to linearize and control the system even when the held object has unknown mass properties. If saturation effects are ignored, an unconstrained quadratic optimization can be performed to distribute the load optimally among the joint actuators.

A three-day anatomy revision course taught by senior peers effectively prepares junior students for their national anatomy exam.

PubMed

Rengier, Fabian; Rauch, Philipp Julian; Partovi, Sasan; Kirsch, Joachim; Nawrotzki, Ralph

2010-12-20

this study examines whether peer-teaching, in the setting of a three-day revision course in anatomy, is effective in preparing medical students for their national anatomy exam. the anatomy course was designed for candidates taking the first part of the German national medical exam. Increase of knowledge during the course was assessed by tests before and after the course (group A). To test equivalence, two control groups participated in the pre-test (group B) or in the course and in the post-test (group C). Participants anonymously rated 14 feedback items on a five-point Likert scale ranging from 1 (full agreement) to 5 (full disagreement). group A students' performance improved significantly during the course with a mean increase of 7.15 points (11.9% improvement; p<0.001). Equivalence testing showed that performance of group A students in the pre-/post-tests was equal to those of group B pre-tests and group C post-tests, respectively. Agreement on the 14 feedback items was highly significant (p<0.001 for all items), with a global median of 1. this study shows that a three-day anatomy revision course is effective and highly appreciated by medical students in their preparation for the national exam. Moreover, peer-teaching is reliable at this stage of the medical curriculum. 2010 Elsevier GmbH. All rights reserved.

In Forests Globally, Large Trees Suffer Most during Drought

NASA Astrophysics Data System (ADS)

Bennett, A. C.; McDowell, N. G.; Allen, C. D.; Anderson-Teixeira, K. J.

2014-12-01

Globally, drought events are increasing in both frequency and intensity. Spatial and temporal variation in water availability is expected to alter the ecophysiology and structure of forests, with consequent feedbacks to climate change. Extensive tree mortality induced by heat and aridity has been documented across a range of latitudes, and several global vegetation models have simulated widespread forest die-off in the future. The impact of drought on forest structure and function will depend on the differential responses of trees of different sizes. Understanding the size-dependence of drought-induced mortality is necessary to predict local and global impacts. Here we show that in forests worldwide, drought has a greater impact on the growth and mortality of large trees compared to smaller trees. This trend holds true for forests ranging from semiarid woodlands to tropical rainforests. This finding contrasts with what would be expected if deep root access to water were the primary determinant of tree drought response. Rather, the greater drought response of larger trees could be driven by greater inherent vulnerability of large trees to hydraulic stress or by canopy position becoming more of a liability under drought, as exposed crowns face higher evaporative demand. These findings imply that future droughts will have a disproportionate effect on large trees, resulting in a larger feedback to climate change than would occur if all tree size classes were equally affected by drought.

Vegetation-climate feedbacks in the conversion of tropical savanna to grassland

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

Hoffmann, W.A.; Jackson, R.B.

2000-05-01

Tropical savannas have been heavily impacted by human activity, with large expanses transformed from a mixture of trees and grasses to open grassland and agriculture. The National Center for Atmospheric Research (NCAR) CCM3 general circulation model, coupled with the NCAR Land Surface Model, was used to simulate the effects of this conversion on regional climate. Conversion of savanna to grassland reduced precipitation by approximately 10% in four of the five savanna regions under study; only the northern African savannas showed no significant decline. Associated with this decline was an increase in the frequency of dry periods within the wet season,more » a change that could be particularly damaging to shallow-rooted crops. The overall decline in precipitation is almost equally attributable to changes in albedo and roughness length. Conversion to grassland increased mean surface air temperature of all the regions by 0.5 C, primarily because of reductions in surface roughness length. Rooting depth, which decreases dramatically with the conversion of savanna to grassland, contributed little to the overall effect of savanna conversion, but deeper rooting had a small positive effect on latent heat flux with a corresponding reduction in sensible heat flux. The authors propose that the interdependence of climate and vegetation in these regions is manifested as a positive feedback loop in which anthropogenic impacts on savanna vegetation are exacerbated by declines in precipitation.« less

Virulence of oomycete pathogens from Phragmites australis-invaded and noninvaded soils to seedlings of wetland plant species

PubMed Central

Crocker, Ellen V; Karp, Mary Ann; Nelson, Eric B

2015-01-01

Soil pathogens affect plant community structure and function through negative plant–soil feedbacks that may contribute to the invasiveness of non-native plant species. Our understanding of these pathogen-induced soil feedbacks has relied largely on observations of the collective impact of the soil biota on plant populations, with few observations of accompanying changes in populations of specific soil pathogens and their impacts on invasive and noninvasive species. As a result, the roles of specific soil pathogens in plant invasions remain unknown. In this study, we examine the diversity and virulence of soil oomycete pathogens in freshwater wetland soils invaded by non-native Phragmites australis (European common reed) to better understand the potential for soil pathogen communities to impact a range of native and non-native species and influence invasiveness. We isolated oomycetes from four sites over a 2-year period, collecting nearly 500 isolates belonging to 36 different species. These sites were dominated by species of Pythium, many of which decreased seedling survival of a range of native and invasive plants. Despite any clear host specialization, many of the Pythium species were differentially virulent to the native and non-native plant species tested. Isolates from invaded and noninvaded soils were equally virulent to given individual plant species, and no apparent differences in susceptibility were observed between the collective groups of native and non-native plant species. PMID:26078850

Quasar outflows and AGN feedback in the extreme UV: HST/COS observations of HE 0238-1904

NASA Astrophysics Data System (ADS)

Arav, Nahum; Borguet, Benoit; Chamberlain, Carter; Edmonds, Doug; Danforth, Charles

2013-12-01

Spectroscopic observations of quasar outflows at rest-frame 500-1000 Å have immense diagnostic power. We present analyses of such data, where absorption troughs from O IV and O IV* allow us to obtain the distance of the outflows from the AGN and troughs from Ne VIII and Mg X reveal the warm absorber phase of the outflow. Their inferred column densities, combined with those of O VI, N IV and H I, yield two important results. (1) The outflow shows two ionization phases, where the high-ionization phase carries the bulk of the material. This is similar to the situation seen in X-ray warm absorber studies. Furthermore, the low-ionization phase is inferred to have a volume filling factor of 10-5-10-6. (2) We determine a distance of 3000 pc from the outflow to the central source using the O IV*/O IV column density ratio and the knowledge of the ionization parameter. Since this is a typical high-ionization outflow, we can determine robust values for the outflow's mass flux and kinetic luminosity of 40 M⊙ yr-1 and 1045 erg s-1, respectively, where the latter is roughly equal to 1 per cent of the bolometric luminosity. Such a large kinetic luminosity and mass flow rate measured in a typical high-ionization wind suggest that quasar outflows are a major contributor to AGN feedback mechanisms.

The energetics of AGN radiation pressure-driven outflows

NASA Astrophysics Data System (ADS)

Ishibashi, W.; Fabian, A. C.; Maiolino, R.

2018-05-01

The increasing observational evidence of galactic outflows is considered as a sign of active galactic nucleus (AGN) feedback in action. However, the physical mechanism responsible for driving the observed outflows remains unclear, and whether it is due to momentum, energy, or radiation is still a matter of debate. The observed outflow energetics, in particular the large measured values of the momentum ratio (\\dot{p}/(L/c) ˜ 10) and energy ratio (\\dot{E}_k/L ˜ 0.05), seems to favour the energy-driving mechanism; and most observational works have focused their comparison with wind energy-driven models. Here, we show that AGN radiation pressure on dust can adequately reproduce the observed outflow energetics (mass outflow rate, momentum flux, and kinetic power), as well as the scalings with luminosity, provided that the effects of radiation trapping are properly taken into account. In particular, we predict a sublinear scaling for the mass outflow rate (\\dot{M} ∝ L^{1/2}) and a superlinear scaling for the kinetic power (\\dot{E}_k ∝ L^{3/2}), in agreement with the observational scaling relations reported in the most recent compilation of AGN outflow data. We conclude that AGN radiative feedback can account for the global outflow energetics, at least equally well as the wind energy-driving mechanism, and therefore both physical models should be considered in the interpretation of future AGN outflow observations.

Mechanisms of value-learning in the guidance of spatial attention.

PubMed

Anderson, Brian A; Kim, Haena

2018-05-11

The role of associative reward learning in the guidance of feature-based attention is well established. The extent to which reward learning can modulate spatial attention has been much more controversial. At least one demonstration of a persistent spatial attention bias following space-based associative reward learning has been reported. At the same time, multiple other experiments have been published failing to demonstrate enduring attentional biases towards locations at which a target, if found, yields high reward. This is in spite of evidence that participants use reward structures to inform their decisions where to search, leading some to suggest that, unlike feature-based attention, spatial attention may be impervious to the influence of learning from reward structures. Here, we demonstrate a robust bias towards regions of a scene that participants were previously rewarded for selecting. This spatial bias relies on representations that are anchored to the configuration of objects within a scene. The observed bias appears to be driven specifically by reinforcement learning, and can be observed with equal strength following non-reward corrective feedback. The time course of the bias is consistent with a transient shift of attention, rather than a strategic search pattern, and is evident in eye movement patterns during free viewing. Taken together, our findings reconcile previously conflicting reports and offer an integrative account of how learning from feedback shapes the spatial attention system. Copyright © 2018 Elsevier B.V. All rights reserved.

Alcohol use among university students in Sweden measured by an electronic screening instrument

PubMed Central

Andersson, Agneta; Wiréhn, Ann-Britt; Ölvander, Christina; Ekman, Diana Stark; Bendtsen, Preben

2009-01-01

Background Electronic-based alcohol screening and brief interventions for university students with problem drinking behaviours forms an important means by which to identify risky drinkers. Methods In this study an e-SBI project was implemented to assess drinking patterns, and to provide personalised feedback about alcohol consumption and related health problems, to students in a Swedish university. In this study, third semester university students (n = 2858) from all faculties (colleges) at the University were invited to participate in e-SBI screenings. This study employed a randomised controlled trial, with respondents having a equal chance of being assigned to a limited, or full-feedback response. Results The study shows that high risk drinkers tend to underestimate their own consumption compared to others, and that these high risk drinkers experience more negative consequences after alcohol intake, than other respondents. There was a strong belief, for both high- and low-risk drinkers, that alcohol helped celebrations be more festive. This study also confirms findings from other study locations that while males drank more than females in our study population; females reached the same peak alcohol blood concentrations as males. Conclusion Obtaining clear and current information on drinking patterns demonstrated by university students can help public health officials, university administration, and local health care providers develop appropriate prevention and treatment strategies. PMID:19594906

Eye Care Quality and Accessibility Improvement in the Community (EQUALITY) for adults at risk for glaucoma: study rationale and design.

PubMed

Owsley, Cynthia; Rhodes, Lindsay A; McGwin, Gerald; Mennemeyer, Stephen T; Bregantini, Mary; Patel, Nita; Wiley, Demond M; LaRussa, Frank; Box, Dan; Saaddine, Jinan; Crews, John E; Girkin, Christopher A

2015-11-18

Primary open angle glaucoma is a chronic, progressive eye disease that is the leading cause of blindness among African Americans. Glaucoma progresses more rapidly and appears about 10 years earlier in African Americans as compared to whites. African Americans are also less likely to receive comprehensive eye care when glaucoma could be detected before irreversible blindness. Screening and follow-up protocols for managing glaucoma recommended by eye-care professional organizations are often not followed by primary eye-care providers, both ophthalmologists and optometrists. There is a pressing need to improve both the accessibility and quality of glaucoma care for African Americans. Telemedicine may be an effective solution for improving management and diagnosis of glaucoma because it depends on ocular imaging and tests that can be electronically transmitted to remote reading centers where tertiary care specialists can examine the results. We describe the Eye Care Quality and Accessibility Improvement in the Community project (EQUALITY), set to evaluate a teleglaucoma program deployed in retail-based primary eye care practices serving communities with a large percentage of African Americans. We conducted an observational, 1-year prospective study based in two Walmart Vision Centers in Alabama staffed by primary care optometrists. EQUALITY focuses on new or existing adult patients who are at-risk for glaucoma or already diagnosed with glaucoma. Patients receive dilated comprehensive examinations and diagnostic testing for glaucoma, followed by the optometrist's diagnosis and a preliminary management plan. Results are transmitted to a glaucoma reading center where ophthalmologists who completed fellowship training in glaucoma review results and provide feedback to the optometrist, who manages the care of the patient. Patients also receive eye health education about glaucoma and comprehensive eye care. Research questions include diagnostic and management agreement between providers, the impact of eye health education on patients' knowledge and adherence to follow-up and medication, patient satisfaction, program cost-effectiveness, and EQUALITY's impact on Walmart pharmacy prescription rates. As eye-care delivery systems in the US strive to improve quality while reducing costs, telemedicine programs including teleglaucoma initiatives such as EQUALITY could contribute toward reaching this goal, particularly among underserved populations at-risk for chronic blinding diseases.

Frequency offset locking of AlGaAs semiconductor lasers

NASA Astrophysics Data System (ADS)

Kuboki, Katsuhiko; Ohtsu, Motoichi

1987-04-01

Frequency offset locking is proposed as a technique for tracking and sweeping of a semiconductor laser frequency to improve temporal coherence in semiconductor lasers. Experiments were carried out in which a frequency stabilized laser (of residual frequency fluctuation value of 140 Hz at the integration time between 100 ms and 100 s) was used as a master laser, using a digital phase comparator of a large dynamic range (2 pi x 10 to the 11th rad) in the feedback loop to reduce the phase fluctuations of the beat signal between the master laser and the slave laser. As a result, residual frequency fluctuations of the beat signal were as low as 11 Hz at the integration time of 100 s (i.e., the residual frequency fluctuations of the slave laser were almost equal to those of the master laser).

On the wind production from hot accretion flows with different accretion rates

NASA Astrophysics Data System (ADS)

Bu, De-Fu; Gan, Zhao-Ming

2018-02-01

We perform two-dimensional simulations to study how the wind strength changes with accretion rate. We take into account bremsstrahlung, synchrotron radiation and the Comptonization. We find that when the accretion rate is low, radiative cooling is not important, and the accretion flow is hot. For the hot accretion flow, wind is very strong. The mass flux of wind can be ˜ 50 per cent of the mass inflow rate. When the accretion rate increases to a value at which radiative cooling rate is roughly equal to or slightly larger than viscous heating rate, cold clumps can form around the equatorial plane. In this case, the gas pressure gradient force is small and wind is very weak. Our results may be useful for the sub-grid model of active galactic nuclear feedback study.

Digital automatic gain amplifier

NASA Technical Reports Server (NTRS)

Holley, L. D.; Ward, J. O. (Inventor)

1978-01-01

A circuit is described for adjusting the amplitude of a reference signal to a predetermined level so as to permit subsequent data signals to be interpreted correctly. The circuit includes an operational amplifier having a feedback circuit connected between an output terminal and an input terminal; a bank of relays operably connected to a plurality of resistors; and a comparator comparing an output voltage of the amplifier with a reference voltage and generating a compared signal responsive thereto. Means is provided for selectively energizing the relays according to the compared signal from the comparator until the output signal from the amplifier equals to the reference signal. A second comparator is provided for comparing the output of the amplifier with a second voltage source so as to illuminate a lamp when the output signal from the amplifier exceeds the second voltage.

Mechanical gating of a mechanochemical reaction cascade

NASA Astrophysics Data System (ADS)

Wang, Junpeng; Kouznetsova, Tatiana B.; Boulatov, Roman; Craig, Stephen L.

2016-11-01

Covalent polymer mechanochemistry offers promising opportunities for the control and engineering of reactivity. To date, covalent mechanochemistry has largely been limited to individual reactions, but it also presents potential for intricate reaction systems and feedback loops. Here we report a molecular architecture, in which a cyclobutane mechanophore functions as a gate to regulate the activation of a second mechanophore, dichlorocyclopropane, resulting in a mechanochemical cascade reaction. Single-molecule force spectroscopy, pulsed ultrasonication experiments and DFT-level calculations support gating and indicate that extra force of >0.5 nN needs to be applied to a polymer of gated gDCC than of free gDCC for the mechanochemical isomerization gDCC to proceed at equal rate. The gating concept provides a mechanism by which to regulate stress-responsive behaviours, such as load-strengthening and mechanochromism, in future materials designs.

Combined use of autogenic therapy and biofeedback in training effective control of heart rate by humans

NASA Technical Reports Server (NTRS)

Cowings, P. S.

1977-01-01

Experiments were performed on 24 men and women (aged 20-27 yr) in three equal groups who were taught to control their own heart rates by autogenic training and biofeedback under dark and sound-isolated conditions. Group I was parasympathetic dominant, group II was sympathetic dominant, and group III consisted of parasympathetic-dominant subjects and controls who received only biofeedback of their own heart rates. The results corroborate three hypotheses: (1) subjects with para-sympathetic-dominant autonomic profiles perform in a way that is both qualitatively and quantitatively different from subjects with sympathetic-dominant autonomic profiles; (2) tests of interindividual variability yield data relevant to individual performance in visceral learning tasks; and (3) the combined use of autogenic training, biofeedback, and verbal feedback is suitable for conditioning large stable autonomic responses in humans.

Passive thermo-optic feedback for robust athermal photonic systems

DOEpatents

Rakich, Peter T.; Watts, Michael R.; Nielson, Gregory N.

2015-06-23

Thermal control devices, photonic systems and methods of stabilizing a temperature of a photonic system are provided. A thermal control device thermally coupled to a substrate includes a waveguide for receiving light, an absorption element optically coupled to the waveguide for converting the received light to heat and an optical filter. The optical filter is optically coupled to the waveguide and thermally coupled to the absorption element. An operating point of the optical filter is tuned responsive to the heat from the absorption element. When the operating point is less than a predetermined temperature, the received light is passed to the absorption element via the optical filter. When the operating point is greater than or equal to the predetermined temperature, the received light is transmitted out of the thermal control device via the optical filter, without being passed to the absorption element.

Climate-Rotation Feedback on Mars

NASA Technical Reports Server (NTRS)

Bills, Bruce G.

1999-01-01

A new model is presented for the coupled evolution of climate and rotation, as applied to Mars. It has long been appreciated that changes in the orbital and rotational geometry of Mars will influence the seasonal and latitudinal pattern of insolation, and this will likely dominate climatic fluctuations on time scales of 10(exp 5) to 10(exp 7) years. Equally important, but less widely appreciated, is the influence climatic change can have on rotational dynamics. The primary means by which climate influences rotation is via its influence on transport of mass (volatiles and dust) into and out of the polar regions. Many important issues remain unresolved: What are the ages of the polar caps? What climatic periods are recorded in the polar layered deposits? What is the long term obliquity history? Additional information is contained in the original extended abstract.

Visual illusion of tool use recalibrates tactile perception

PubMed Central

Miller, Luke E.; Longo, Matthew R.; Saygin, Ayse P.

2018-01-01

Brief use of a tool recalibrates multisensory representations of the user’s body, a phenomenon called tool embodiment. Despite two decades of research, little is known about its boundary conditions. It has been widely argued that embodiment requires active tool use, suggesting a critical role for somatosensory and motor feedback. The present study used a visual illusion to cast doubt on this view. We used a mirror-based setup to induce a visual experience of tool use with an arm that was in fact stationary. Following illusory tool use, tactile perception was recalibrated on this stationary arm, and with equal magnitude as physical use. Recalibration was not found following illusory passive tool holding, and could not be accounted for by sensory conflict or general interhemispheric plasticity. These results suggest visual tool-use signals play a critical role in driving tool embodiment. PMID:28196765

Displacement sensor based on intra-cavity tuning of dual-frequency gas laser

NASA Astrophysics Data System (ADS)

Niu, Haisha; Niu, Yanxiong; Liu, Ning; Li, Jiyang

2018-01-01

A nanometer-resolution displacement measurement instrument based on tunable cavity frequency-splitting method is presented. One beam is split into two orthogonally polarized beams when anisotropic element inserted in the cavity. The two beams with fixed frequency difference are modulated by the movement of the reflection mirror. The changing law of the power tuning curves between the total output and the two orthogonally polarized beams is researched, and a method splitting one tuning cycle to four equal parts is proposed based on the changing law, each part corresponds to one-eighth wavelength of displacement. A laser feedback interferometer (LFI) and piezoelectric ceramic are series connected to the sensor head to calibrate the displacement that less than one-eighth wavelength. The displacement sensor achieves to afford measurement range of 20mm with resolution of 6.93nm.

The Effect of Information Feedback Upon Psychophysical Judgments

NASA Technical Reports Server (NTRS)

Atkinson, Richard C.; Carterette, Edward C.; Kinchla, Ronald A.

1964-01-01

An analysis was made of the role of presentation schedules and information feedback on performance in a forced-choice signal detection task. The experimental results indicate that information feedback facilitates performance, but only for certain presentation schedules. The present study was designed to assess performance in a signal detection task under two conditions of information feedback. In the I-condition, S was told on each trial whether his detection response was correct or incorrect; in the !-condition S was given no feedback regarding the correctness of his response. The task involved a 2-response, forced-choice auditory detection problem. On each trial 2 temporal intervals were defined and S was required to report which interval he believed contained the signal; i. e., in one interval a tone burst in a background of white noise was presented, while the other interval contained only white noise. A trial will be denoted as s1 or s2, depending on whether the signal was embedded in the 1st or 2nd interval; the S's response will be denoted A1 or A2 to indicate which interval he reported contained the signal. The probability of an s1 trial will be denoted as y. In this study two values of y were used (.50 and.75) and, as indicated above, two conditions of information feedback. Thus there were 4 experimental conditions (501, · 50I, 751, 75I); each S was run under all 4 conditions. Method Gaussian noise was presented binaurally in S's headphones throughout a test session and the signal was a 1000-cps sinusoid tone; the tone was presented for 100 msec. including equal fall and rise times of 20 msec. The ratio of signal energy to noise power in a unit bandwidth was 2.9, and was constant throughout the study. The. S was seated before a stimulus display board. On each trial a red warning light was flashed for 100 msec. Two amber lights then came on successively each for 1 sec.; these lights defined the 2 observation intervals. The onset of the signal occurred 500 msec. after the onset of one of the observation intervals. After the second amber light went off, S indicated his response by pressing 1 of 2 wand switches under cards reading "1st interval" and "2nd interval." For the !-condition a green light flashed on above the correct response key after S's response; the green light was omitted in the !-condition. Each trial lasted 6 sec. The S's were 12 male college students with normal hearing. They were run for two practice sessions followed by 20 test sessions. Test sessions were run on consecutive days, 350 trials/day. Each day S ran on 1 of the 4 experimental conditions; in successive 4-day blocks S ran one day on each of the 4 experimental conditions in a random order. Thus, over 20 days each of the experimental conditions was repeated 5 times.

Generation of GHS Scores from TEST and online sources ...

EPA Pesticide Factsheets

Alternatives assessment frameworks such as DfE (Design for the Environment) evaluate chemical alternatives in terms of human health effects, ecotoxicity, and fate. T.E.S.T. (Toxicity Estimation Software Tool) can be utilized to evaluate human health in terms of acute oral rat toxicity, developmental toxicity, endocrine activity, and mutagenicity. It can be used to evaluate ecotoxicity (in terms of acute fathead minnow toxicity) and fate (in terms of bioconcentration factor). It also be used to estimate a variety of key physicochemical properties such as melting point, boiling point, vapor pressure, water solubility, and bioconcentration factor. A web-based version of T.E.S.T. is currently being developed to allow predictions to be made from other web tools. Online data sources such as from NCCT’s Chemistry Dashboard, REACH dossiers, or from ChemHat.org can also be utilized to obtain GHS (Global Harmonization System) scores for comparing alternatives. The purpose of this talk is to show how GHS (Global Harmonization Score) data can be obtained from literature sources and from T.E.S.T. (Toxicity Estimation Software Tool). This data will be used to compare chemical alternatives in the alternatives assessment dashboard (a 2018 CSS product).

Polymer-entanglement-driven coassembly of hybrid superparamagnetic nanoparticles: Tunable structures and flexible functionalization.

PubMed

Zhan, Xiaohui; Yi, Qiangying; Cai, Shuang; Zhou, Xiaoxi; Ma, Shaohua; Lan, Fang; Gu, Zhongwei; Wu, Yao

2017-12-15

In this study, we report a facile and versatile strategy for preparing a type of pH-responsive superparamagnetic hybrid coassemblies featuring a series of controls over the morphology and multi-functionalization simultaneously and efficiently. Via the entanglement interactions, the combine of fixed PEG-b-P4VP modified Fe 3 O 4 NPs (D-Fe 3 O 4 @mPEG-b-P4VP) and different well-designed free PEG-b-P4VP, which are analogous to two amphiphiles, contributes these hybrid superstructures with multiple, well-defined morphologies and targeted fluorescent properties. In contrast to other studies, our work overcame several defects (e.g., interior NPs' randomness, cumbersome assembly parameter adjustment and functionalization) of the conventional assembly of modified inorganic NPs and demonstrated that this coassembly strategy can be used as a versatile tool for the controllable assembly of other NPs or polymers. Finally, taking the coassembly C1 as a desirable drug delivery carrier, good biocompatibility and pH-triggered drug release were successfully verified. The current study indicated that these magnetic coassemblies are promising as multifunctional and multipurpose carriers in biological, medical, catalytic, and coating applications. Copyright © 2017. Published by Elsevier Inc.

Dynamic Relaxation: A Technique for Detailed Thermo-Elastic Structural Analysis of Transportation Structures

NASA Astrophysics Data System (ADS)

Shoukry, Samir N.; William, Gergis W.; Riad, Mourad Y.; McBride, Kevyn C.

2006-08-01

Dynamic relaxation is a technique developed to solve static problems through an explicit integration in finite element. The main advantage of such a technique is the ability to solve a large problem in a relatively short time compared with the traditional implicit techniques, especially when using nonlinear material models. This paper describes the use of such a technique in analyzing large transportation structures as dowel jointed concrete pavements and 306-m-long, reinforced concrete bridge superstructure under the effect of temperature variations. The main feature of the pavement model is the detailed modeling of dowel bars and their interfaces with the surrounding concrete using extremely fine mesh of solid elements, while in the bridge structure it is the detailed modeling of the girder-deck interface as well as the bracing members between the girders. The 3DFE results were found to be in a good agreement with experimentally measured data obtained from an instrumented pavements sections and a highway bridge constructed in West Virginia. Thus, such a technique provides a good tool for analyzing the response of large structures to static loads in a fraction of the time required by traditional, implicit finite element methods.

Telemedicine delivery of patient education in remote Ontario communities: feasibility of an Advanced Clinician Practitioner in Arthritis Care (ACPAC)-led inflammatory arthritis education program.

PubMed

Warmington, Kelly; Flewelling, Carol; Kennedy, Carol A; Shupak, Rachel; Papachristos, Angelo; Jones, Caroline; Linton, Denise; Beaton, Dorcas E; Lineker, Sydney

2017-01-01

Telemedicine-based approaches to health care service delivery improve access to care. It was recognized that adults with inflammatory arthritis (IA) living in remote areas had limited access to patient education and could benefit from the 1-day Prescription for Education (RxEd) program. The program was delivered by extended role practitioners with advanced training in arthritis care. Normally offered at one urban center, RxEd was adapted for videoconference delivery through two educator development workshops that addressed telemedicine and adult education best practices. This study explores the feasibility of and participant satisfaction with telemedicine delivery of the RxEd program in remote communities. Participants included adults with IA attending the RxEd program at one of six rural sites. They completed post-course program evaluations and follow-up interviews. Educators provided post-course feedback to identify program improvements that were later implemented. In total, 123 people (36 in-person and 87 remote, across 6 sites) participated, attending one of three RxEd sessions. Remote participants were satisfied with the quality of the video-conference (% agree/strongly agree): could hear the presenter (92.9%) and discussion between sites (82.4%); could see who was speaking at other remote sites (85.7%); could see the slides (95.3%); and interaction between sites adequately facilitated (94.0%). Educator and participant feedback were consistent. Suggested improvements included: use of two screens (speaker and slides); frontal camera angles; equal interaction with remote sites; and slide modifications to improve the readability on screen. Interview data included similar constructive feedback but highlighted the educational and social benefits of the program, which participants noted would have been inaccessible if not offered via telemedicine. Study findings confirm the feasibility of delivering the RxEd program to remote communities by using telemedicine. Future research with a focus on the sustainability of this and other models of technology-supported patient education for adults with IA across Ontario is warranted.

Using Online Dialogues to Connect Local Leaders and Climate Experts: Methods, Feedback and Lessons Learned from the Resilience Dialogues

NASA Astrophysics Data System (ADS)

Goodwin, M.; Pandya, R.; Weaver, C. P.; Zerbonne, S.; Bennett, N.; Spangler, B.

2017-12-01

Inclusive, multi-stakeholder dialogue, participatory planning and actionable science are necessary for just and effective climate resilience outcomes. How can we support that in practice? The Resilience Dialogues launched a public Beta in 2016-2017 to allow scientists and resilience practitioners to engage with local leaders from 10 communities around the US through a series of facilitated, online dialogues. We developed two, one-week dialogues for each community: one to consider ways to respond to observed and anticipated climate impacts through a resilience lens, and one to identify next steps and resources to advance key priorities. We divided the communities into three cohorts and refined the structure and facilitation strategy for these dialogues from one to the next based on participant feedback. This adaptive method helped participants engage in the dialogues more effectively and develop useful results. We distributed a survey to all participants following each cohort to capture feedback on the use and utility of the dialogues. While there was room for improvement in the program's technical interface, survey participants valued the dialogues and the opportunity to engage as equals. Local leaders said the dialogues helped identify new local pathways to approach resilience priorities. They felt they benefited from focused conversation and personalized introductions to best-matched resources. Practitioners learned how local leaders seek to apply climate science, and how to effectively communicate their expertise to community leaders in support of local planning efforts. We learned there is demand for specialized dialogues on issues like communication, financing and extreme weather. Overall, the desire of participants to continue to engage through this program, and others to enter, indicates that facilitated, open conversations between experts and local leaders can break down communication and access barriers between climate services providers and end-users. This presentation will share lessons learned from this process and methods that we found most effective.

Chiral Symmetry Breaking and Complete Chiral Purity by Thermodynamic-Kinetic Feedback Near Equilibrium: Implications for the Origin of Biochirality

NASA Astrophysics Data System (ADS)

Viedma, Cristobal

2007-05-01

Chiral symmetry breaking occurs when a physical or chemical process spontaneously generates a large excess of one of the two enantiomers-left-handed (L) or right-handed (D)--with no preference as to which of the two enantiomers is produced. From the viewpoint of energy, these two enantiomers can exist with an equal probability, and inorganic processes that involve chiral products commonly yield a racemic mixture of both. The fact that biologically relevant molecules exist only as one of the two enantiomers is a fascinating example of complete symmetry breaking in chirality and has long intrigued the science community. The origin of this selective chirality has remained a fundamental enigma with regard to the origin of life since the time of Pasteur, some 140 years ago. Here, it is shown that two populations of chiral crystals of left and right hand cannot coexist in solution: one of the chiral populations disappears in an irreversible autocatalytic process that nurtures the other one. Final and complete chiral purity seems to be an inexorable fate in the course of the common process of growth-dissolution. This unexpected chiral symmetry breaking can be explained by the feedback between the thermodynamic control of dissolution and the kinetics of the growth process near equilibrium. This ``thermodynamic-kinetic feedback near equilibrium'' is established as a mechanism to achieve complete chiral purity in solid state from a previously solid racemic medium. The way in which this mechanism could operate in solutions of chiral biomolecules is described. Finally, based on this mechanism, experiments designed to search for chiral purity in a new way are proposed: chiral purity of amino acids or biopolymers is predicted in solid phase from a previously solid racemic medium. This process may have played a key role in the origin of biochirality.

Feasibility of a real-time self-monitoring device for sitting less and moving more: a randomised controlled trial

PubMed Central

Martin, Anne; Adams, Jacob M; Bunn, Christopher; Gill, Jason M R; Gray, Cindy M; Hunt, Kate; Maxwell, Douglas J; van der Ploeg, Hidde P; Wyke, Sally

2017-01-01

Objectives Time spent inactive and sedentary are both associated with poor health. Self-monitoring of walking, using pedometers for real-time feedback, is effective at increasing physical activity. This study evaluated the feasibility of a new pocket-worn sedentary time and physical activity real-time self-monitoring device (SitFIT). Methods Forty sedentary men were equally randomised into two intervention groups. For 4 weeks, one group received a SitFIT providing feedback on steps and time spent sedentary (lying/sitting); the other group received a SitFIT providing feedback on steps and time spent upright (standing/stepping). Change in sedentary time, standing time, stepping time and step count was assessed using activPAL monitors at baseline, 4-week follow-up (T1) and 12-week (T2) follow-up. Semistructured interviews were conducted after 4 and 12 weeks. Results The SitFIT was reported as acceptable and usable and seen as a motivating tool to reduce sedentary time by both groups. On average, participants reduced their sedentary time by 7.8 minutes/day (95% CI −55.4 to 39.7) (T1) and by 8.2 minutes/day (95% CI −60.1 to 44.3) (T2). They increased standing time by 23.2 minutes/day (95% CI 4.0 to 42.5) (T1) and 16.2 minutes/day (95% CI −13.9 to 46.2) (T2). Stepping time was increased by 8.5 minutes/day (95% CI 0.9 to 16.0) (T1) and 9.0 minutes/day (95% CI 0.5 to 17.5) (T2). There were no between-group differences at either follow-up time points. Conclusion The SitFIT was perceived as a useful tool for self-monitoring of sedentary time. It has potential as a real-time self-monitoring device to reduce sedentary and increase upright time. PMID:29081985

A proportional control scheme for high density force myography.

PubMed

Belyea, Alexander T; Englehart, Kevin B; Scheme, Erik J

2018-08-01

Force myography (FMG) has been shown to be a potentially higher accuracy alternative to electromyography for pattern recognition based prosthetic control. Classification accuracy, however, is just one factor that affects the usability of a control system. Others, like the ability to start and stop, to coordinate dynamic movements, and to control the velocity of the device through some proportional control scheme can be of equal importance. To impart effective fine control using FMG-based pattern recognition, it is important that a method of controlling the velocity of each motion be developed. In this work force myography data were collected from 14 able bodied participants and one amputee participant as they performed a set of wrist and hand motions. The offline proportional control performance of a standard mean signal amplitude approach and a proposed regression-based alternative was compared. The impact of providing feedback during training, as well as the use of constrained or unconstrained hand and wrist contractions, were also evaluated. It is shown that the commonly used mean of rectified channel amplitudes approach commonly employed with electromyography does not translate to force myography. The proposed class-based regression proportional control approach is shown significantly outperform this standard approach (ρ  <  0.001), yielding a R 2 correlation coefficients of 0.837 and 0.830 for constrained and unconstrained forearm contractions, respectively for able bodied participants. No significant difference (ρ  =  0.693) was found in R 2 performance when feedback was provided during training or not. The amputee subject achieved a classification accuracy of 83.4%  ±  3.47% demonstrating the ability to distinguish contractions well with FMG. In proportional control the amputee participant achieved an R 2 of of 0.375 for regression based proportional control during unconstrained contractions. This is lower than the unconstrained case for able-bodied subjects for this particular amputee, possibly due to difficultly in visualizing contraction level modulation without feedback. This may be remedied in the use of a prosthetic limb that would provide real-time feedback in the form of device speed. A novel class-specific regression-based approach is proposed for multi-class control is described and shown to provide an effective means of providing FMG-based proportional control.

On the failure to notice that White people are White: Generating and testing hypotheses in the celebrity guessing game.

PubMed

Hegarty, Peter

2017-01-01

Drawing together social psychologists' concerns with equality and cognitive psychologists' concerns with scientific inference, 6 studies (N = 841) showed how implicit category norms make the generation and test of hypothesis about race highly asymmetric. Having shown that Whiteness is the default race of celebrity actors (Study 1), Study 2 used a variant of Wason's (1960) rule discovery task to demonstrate greater difficulty in discovering rules that require specifying that race is shared by White celebrity actors than by Black celebrity actors. Clues to the Whiteness of White actors from analogous problems had little effect on hypothesis formation or rule discovery (Studies 3 and 4). Rather, across Studies 2 and 4 feedback about negative cases-non-White celebrities-facilitated the discovery that White actors shared a race, whether participants or experimenters generated the negative cases. These category norms were little affected by making White actors' Whiteness more informative (Study 5). Although participants understood that discovering that White actors are White would be harder than discovering that Black actors are Black, they showed limited insight into the information contained in negative cases (Study 6). Category norms render some identities as implicit defaults, making hypothesis formation and generalization about real social groups asymmetric in ways that have implications for scientific reasoning and social equality. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

A hybrid integrated services digital network-internet protocol solution for resident education.

PubMed

Erickson, Delnora; Greer, Lester; Belard, Arnaud; Tinnel, Brent; O'Connell, John

2010-05-01

The purpose of this study was to explore the effectiveness of incorporating Web-based application sharing of virtual medical simulation software within a multipoint video teleconference (VTC) as a training tool in graduate medical education. National Capital Consortium Radiation Oncology Residency Program resident and attending physicians participated in dosimetry teaching sessions held via VTC using Acrobat Connect application sharing. Residents at remote locations could take turns designing radiation treatments using standard three-dimensional planning software, whereas instructors gave immediate feedback and demonstrated proper techniques. Immediately after each dosimetry lesson, residents were asked to complete a survey that evaluated the effectiveness of the session. At the end of a 3-month trial of using Adobe Connect, residents completed a final survey that compared this teaching technology to the prior VTC-alone method. The mean difference from equality across all quality measures from the weekly survey was 0.8, where 0 indicated neither enhanced nor detracted from the learning experience and 1 indicated a minor enhancement in the learning experience. The mean difference from equality across all measures from the final survey comparing use of application sharing with VTC to VTC alone was 1.5, where 1 indicated slightly better and 2 indicated a somewhat better experience. The teaching efficacy of multipoint VTC is perceived by medical residents to be more effective when complemented by application-sharing software such as Adobe Acrobat Connect.

The Developmental Dynamics of Terrorist Organizations

PubMed Central

Clauset, Aaron; Gleditsch, Kristian Skrede

2012-01-01

We identify robust statistical patterns in the frequency and severity of violent attacks by terrorist organizations as they grow and age. Using group-level static and dynamic analyses of terrorist events worldwide from 1968–2008 and a simulation model of organizational dynamics, we show that the production of violent events tends to accelerate with increasing size and experience. This coupling of frequency, experience and size arises from a fundamental positive feedback loop in which attacks lead to growth which leads to increased production of new attacks. In contrast, event severity is independent of both size and experience. Thus larger, more experienced organizations are more deadly because they attack more frequently, not because their attacks are more deadly, and large events are equally likely to come from large and small organizations. These results hold across political ideologies and time, suggesting that the frequency and severity of terrorism may be constrained by fundamental processes. PMID:23185267

Note: high precision angle generator using multiple ultrasonic motors and a self-calibratable encoder.

PubMed

Kim, Jong-Ahn; Kim, Jae Wan; Kang, Chu-Shik; Jin, Jonghan; Eom, Tae Bong

2011-11-01

We present an angle generator with high resolution and accuracy, which uses multiple ultrasonic motors and a self-calibratable encoder. A cylindrical air bearing guides a rotational motion, and the ultrasonic motors achieve high resolution over the full circle range with a simple configuration. The self-calibratable encoder can compensate the scale error of a divided circle (signal period: 20") effectively by applying the equal-division-averaged method. The angle generator configures a position feedback control loop using the readout of the encoder. By combining the ac and dc operation mode, the angle generator produced stepwise angular motion with 0.005" resolution. We also evaluated the performance of the angle generator using a precision angle encoder and an autocollimator. The expanded uncertainty (k = 2) in the angle generation was estimated less than 0.03", which included the calibrated scale error and the nonlinearity error. © 2011 American Institute of Physics

Incentives and control in primary health care: findings from English pay-for-performance case studies.

PubMed

McDonald, Ruth; Harrison, Stephen; Checkland, Kath

2008-01-01

The authors' aim was to investigate mechanisms and perceptions of control following the implementation of a new "pay-for-performance" contract (the new General Medical Services, or GMS, contract) in general practice. This article was based on an in-depth qualitative case study approach in two general practices in England. A distinction is emerging amongst ostensibly equal partners between those general practitioners conducting and those subject to surveillance. Attitudes towards the contract were largely positive, although discontent was higher in the practice which employed a more intensive surveillance regime and greater amongst nurses than doctors. The sample was small and opportunistic. Further research is required to examine the longer-term effects as new contractual arrangements evolve. Increased surveillance and feedback mechanisms associated with new pay-for-performance schemes have the potential to constrain and shape clinical practice. The paper highlights the emergence of new tensions within and between existing professional groupings.

Flight Test Validation of Optimal Input Design and Comparison to Conventional Inputs

NASA Technical Reports Server (NTRS)

Morelli, Eugene A.

1997-01-01

A technique for designing optimal inputs for aerodynamic parameter estimation was flight tested on the F-18 High Angle of Attack Research Vehicle (HARV). Model parameter accuracies calculated from flight test data were compared on an equal basis for optimal input designs and conventional inputs at the same flight condition. In spite of errors in the a priori input design models and distortions of the input form by the feedback control system, the optimal inputs increased estimated parameter accuracies compared to conventional 3-2-1-1 and doublet inputs. In addition, the tests using optimal input designs demonstrated enhanced design flexibility, allowing the optimal input design technique to use a larger input amplitude to achieve further increases in estimated parameter accuracy without departing from the desired flight test condition. This work validated the analysis used to develop the optimal input designs, and demonstrated the feasibility and practical utility of the optimal input design technique.

Demodulation Algorithms for the Ofdm Signals in the Time- and Frequency-Scattering Channels

NASA Astrophysics Data System (ADS)

Bochkov, G. N.; Gorokhov, K. V.; Kolobkov, A. V.

2016-06-01

We consider a method based on the generalized maximum-likelihood rule for solving the problem of reception of the signals with orthogonal frequency division multiplexing of their harmonic components (OFDM signals) in the time- and frequency-scattering channels. The coherent and incoherent demodulators effectively using the time scattering due to the fast fading of the signal are developed. Using computer simulation, we performed comparative analysis of the proposed algorithms and well-known signal-reception algorithms with equalizers. The proposed symbolby-symbol detector with decision feedback and restriction of the number of searched variants is shown to have the best bit-error-rate performance. It is shown that under conditions of the limited accuracy of estimating the communication-channel parameters, the incoherent OFDMsignal detectors with differential phase-shift keying can ensure a better bit-error-rate performance compared with the coherent OFDM-signal detectors with absolute phase-shift keying.

The relationship of motion sickness susceptibility to learned autonomic control for symptom suppression

NASA Technical Reports Server (NTRS)

Cowings, P. S.; Toscano, W. B.

1982-01-01

Twenty-four men were randomly assigned to four equal groups matched in terms of their Coriolis Sickness Susceptibility Index (CSSI). Two groups of subjects were highly susceptible to motion sickness, and two groups were moderately susceptible. All subjects were given six C551 tests at 5-d intervals. Treatment Groups I (highly susceptible) and II (moderately susceptible) were taught to control their autonomic responses, using a training method called autogenic-feedback training (AFT) before the third, fourth, and fifth CSSI tests. Control groups III (highly susceptible) and IV (moderately susceptible) received no treatment. Results showed that both treatment groups significantly improved performance on CSSI tests after training; neither of the control groups changed significantly. Highly and moderately susceptible subjects in the two treatment groups improved at comparable rates. Highly susceptible control group subjects did not habituate across tests as readily as the moderately susceptible controls.

Dual comb generation from a mode-locked fiber laser with orthogonally polarized interlaced pulses.

PubMed

Akosman, Ahmet E; Sander, Michelle Y

2017-08-07

Ultra-high precision dual-comb spectroscopy traditionally requires two mode-locked, fully stabilized lasers with complex feedback electronics. We present a novel mode-locked operation regime in a thulium-holmium co-doped fiber laser, a frequency-halved state with orthogonally polarized interlaced pulses, for dual comb generation from a single source. In a linear fiber laser cavity, an ultrafast pulse train composed of co-generated, equal intensity and orthogonally polarized consecutive pulses at half of the fundamental repetition rate is demonstrated based on vector solitons. Upon optical interference of the orthogonally polarized pulse trains, two stable microwave RF beat combs are formed, effectively down-converting the optical properties into the microwave regime. These co-generated, dual polarization interlaced pulse trains, from one all-fiber laser configuration with common mode suppression, thus provide an attractive compact source for dual-comb spectroscopy, optical metrology and polarization entanglement measurements.

Experimental demonstration of multiuser communication in deep water using time reversal.

PubMed

Shimura, T; Ochi, H; Song, H C

2013-10-01

Multiuser communication is demonstrated using experimental data (450-550 Hz) collected in deep water, south of Japan. The multiple users are spatially distributed either in depth or range while a 114-m long, 20-element vertical array (i.e., base station) is deployed to around the sound channel axis (~1000 m). First, signals received separately from ranges of 150 km and 180 km at various depths are combined asynchronously to generate multiuser communication sequences for subsequent processing, achieving an aggregate data rate of 300 bits/s for up to three users. Adaptive time reversal is employed to separate collided packets at the base station, followed by a single channel decision feedback equalizer. Then it is demonstrated that two users separated by 3 km in range at ~1000 m depth can transmit information simultaneously to the base station at ~500 km range with an aggregate data rate of 200 bits/s.

Live as we choose: The role of autonomy support in facilitating intrinsic motivation.

PubMed

Meng, Liang; Ma, Qingguo

2015-12-01

According to Self-determination Theory (SDT), autonomy is a basic psychological need, satisfaction of which may lead to enhanced intrinsic motivation and related beneficial outcomes. By manipulating the opportunity to choose between tasks of equal difficulty, throughout the motivational process, the effect of autonomy support was examined both behaviorally and electrophysiologically. More negative stimulus-preceding negativity (SPN) and an enlarged FRN loss-win difference wave (d-FRN) indicated an enhanced expectation toward the positive outcome (during the anticipation stage) as well as intensified intrinsic motivation toward the task (during the outcome appraisal stage) when choice was available. Taken together, results of the present study suggest d-FRN upon feedback as a real-time electrophysiological indicator of intrinsic/autonomous motivation and illustrate the important role of autonomy-supportive job design in the workplace. Copyright © 2015 Elsevier B.V. All rights reserved.

Condition sensor system and method

NASA Technical Reports Server (NTRS)

Polhemus, J. T.; Morgan, J. E.; Mandell, A. (Inventor)

1978-01-01

The condition sensor system comprises a condition detector which produces a pulse when a parameter of the monitored condition exceeds a desired threshold. A resettable condition counter counts each pulse. A resettable timer is preset to produce a particular time frame. The counter produces a condition signal when the accumulated number of pulses within the time frame is equal to or greater than a preset count. Control means responsive to the incoming pulses and to the condition signal produce control signals that control utilization devices. After a suitable delay, the last detected pulse simultaneously resets the pulse counter and the timer, and prepares them for sensing another condition occurrence within the time frame. The invention has particular utility in the process of detecting rocking motions of blind people. A controlled, audible, bio-feedback signal is provided which constitutes a warning to the blind person that he is rocking.

Cryogenic readout for multiple VUV4 Multi-Pixel Photon Counters in liquid xenon

NASA Astrophysics Data System (ADS)

Arneodo, F.; Benabderrahmane, M. L.; Bruno, G.; Conicella, V.; Di Giovanni, A.; Fawwaz, O.; Messina, M.; Candela, A.; Franchi, G.

2018-06-01

We present the performances and characterization of an array made of S13370-3050CN (VUV4 generation) Multi-Pixel Photon Counters manufactured by Hamamatsu and equipped with a low power consumption preamplifier operating at liquid xenon temperature (∼ 175 K). The electronics is designed for the readout of a matrix of maximum dimension of 8 × 8 individual photosensors and it is based on a single operational amplifier. The detector prototype presented in this paper utilizes the Analog Devices AD8011 current feedback operational amplifier, but other models can be used depending on the application. A biasing correction circuit has been implemented for the gain equalization of photosensors operating at different voltages. The results show single photon detection capability making this device a promising choice for future generation of large scale dark matter detectors based on liquid xenon, such as DARWIN.

Teaching ethics in psychiatry: a one-day workshop for clinical students.

PubMed Central

Green, B; Miller, P D; Routh, C P

1995-01-01

In this paper we describe the objectives of teaching medical ethics to undergraduates and the teaching methods used. We describe a workshop used in the University of Liverpool Department of Psychiatry, designed to enhance ethical sensitivity in psychiatry. The workshop reviews significant historical and current errors in the ethical practice of psychiatry and doctors' defence mechanisms against accepting responsibility for deficiencies in ethical practice. The workshop explores the student doctors' own group ethos in response to ethical dilemmas, and demonstrates how the individual contributes to and is responsible for the group ethos through participation and also through nonparticipation. The student feedback about the workshop is reviewed. The Toronto Ethical Sensitivity Instrument was used to assess whether or not the workshop altered sensitivity. Compared to a control group the attenders' sensitivity was significantly increased (on Student's t-test p equals or is less than 0.002). PMID:7473644

Mathematical modelling of fluid transport and its regulation at multiple scales.

PubMed

Chara, Osvaldo; Brusch, Lutz

2015-04-01

Living matter equals water, to a first approximation, and water transport across barriers such as membranes and epithelia is vital. Water serves two competing functions. On the one hand, it is the fundamental solvent enabling random mobility of solutes and therefore biochemical reactions and intracellular signal propagation. Homeostasis of the intracellular water volume is required such that messenger concentration encodes the stimulus and not inverse volume fluctuations. On the other hand, water flow is needed for transport of solutes to and away from cells in a directed manner, threatening volume homeostasis and signal transduction fidelity of cells. Feedback regulation of fluid transport reconciles these competing objectives. The regulatory mechanisms often span across multiple spatial scales from cellular interactions up to the architecture of organs. Open questions relate to the dependency of water fluxes and steady state volumes on control parameters and stimuli. We here review selected mathematical models of feedback regulation of fluid transport at the cell scale and identify a general "core-shell" structure of such models. We propose that fluid transport models at other spatial scales can be constructed in a generalised core-shell framework, in which the core accounts for the biophysical effects of fluid transport whilst the shell reflects the regulatory mechanisms. We demonstrate the applicability of this framework for tissue lumen growth and suggest future experiments in zebrafish to test lumen size regulation mechanisms. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

A limit cycle oscillator model for cycling mood variations of bipolar disorder patients derived from cellular biochemical reaction equations

NASA Astrophysics Data System (ADS)

Frank, T. D.

2013-08-01

We derive a nonlinear limit cycle model for oscillatory mood variations as observed in patients with cycling bipolar disorder. To this end, we consider two signaling pathways leading to the activation of two enzymes that play a key role for cellular and neural processes. We model pathway cross-talk in terms of an inhibitory impact of the first pathway on the second and an excitatory impact of the second on the first. The model also involves a negative feedback loop (inhibitory self-regulation) for the first pathway and a positive feedback loop (excitatory self-regulation) for the second pathway. We demonstrate that due to the cross-talk the biochemical dynamics is described by an oscillator equation. Under disease-free conditions the oscillatory system exhibits a stable fixed point. The breakdown of the self-inhibition of the first pathway at higher concentration levels is studied by means of a scalar control parameter ξ, where ξ equal to zero refers to intact self-inhibition at all concentration levels. Under certain conditions, stable limit cycle solutions emerge at critical parameter values of ξ larger than zero. These oscillations mimic pathological cycling mood variations that emerge due to a disease-induced bifurcation. Consequently, our modeling analysis supports the notion of bipolar disorder as a dynamical disease. In addition, our study establishes a connection between mechanistic biochemical modeling of bipolar disorder and phenomenological nonlinear oscillator approaches to bipolar disorder suggested in the literature.

Strategy for pH control and pH feedback-controlled substrate feeding for high-level production of L-tryptophan by Escherichia coli.

PubMed

Cheng, Li-Kun; Wang, Jian; Xu, Qing-Yang; Zhao, Chun-Guang; Shen, Zhi-Qiang; Xie, Xi-Xian; Chen, Ning

2013-05-01

Optimum production of L-tryptophan by Escherichia coli depends on pH. Here, we established conditions for optimizing the production of L-tryptophan. The optimum pH range was 6.5-7.2, and pH was controlled using a three-stage strategy [pH 6.5 (0-12 h), pH 6.8 (12-24 h), and pH 7.2 (24-38 h)]. Specifically, ammonium hydroxide was used to adjust pH during the initial 24 h, and potassium hydroxide and ammonium hydroxide (1:2, v/v) were used to adjust pH during 24-38 h. Under these conditions, NH4 (+) and K(+) concentrations were kept below the threshold for inhibiting L-tryptophan production. Optimization was also accomplished using ratios (v/v) of glucose to alkali solutions equal to 4:1 (5-24 h) and 6:1 (24-38 h). The concentration of glucose and the pH were controlled by adjusting the pH automatically. Applying a pH-feedback feeding method, the steady-state concentration of glucose was maintained at approximately 0.2 ± 0.02 g/l, and acetic acid accumulated to a concentration of 1.15 ± 0.03 g/l, and the plasmid stability was 98 ± 0.5 %. The final, optimized concentration of L-tryptophan was 43.65 ± 0.29 g/l from 52.43 ± 0.38 g/l dry cell weight.

Evaluation of Brainstorming Session as a Teaching-learning Tool among Postgraduate Medical Biochemistry Students.

PubMed

Goswami, Binita; Jain, Anju; Koner, Bidhan Chandra

2017-12-01

The thrust for postgraduate teaching should be self-directed learning with equal participation by all students in academic discussions. Group discussions involve conduction of the discourse by a leader who guides the discussion as well as points out any wrong information. This discourages quieter students from participation with the fear of rebuke. Brainstorming is devoid of all such fallacies with no judgment and reprimand. The aim of this study was to use brainstorming as a teaching-learning tool among postgraduate students of medical biochemistry. The project was commenced after due approvals from the research and ethical committee. The participants were enrolled after informed consent and sensitization. All the pro forma and questionnaires were duly validated by experts. After piloting and incorporation of the suggestions for improvisation, the main sessions were planned and implemented. The response was judged by posttest scores and feedback forms. There was an improvement of understanding of the biochemical concepts as assessed by the posttest scores and solving of a similar clinical problem. The students expressed satisfaction with the conduction, timing, and discussion of the clinical problems. The drawbacks of traditional teaching as expressed during the feedback stage were also taken care of by the brainstorming sessions. Our project made the students and the faculty aware about the utility of brainstorming for teaching purposes in medical education which till now was considered efficacious only for troubleshooting in advertising and management institutions. The students were satisfied with this technique for understanding of biochemical concepts.

Quasar Outflows and AGN Feedback in the Extreme UV: HST/COS Observations of QSO HE0238-1904

NASA Astrophysics Data System (ADS)

Arav, Nahum; Borguet, B.; Chamberlain, C.; Edmonds, D.; Danforth, C.

2014-01-01

Spectroscopic observations of quasar outflows at rest-frame 500-1000 Angstrom have immense diagnostic power. We present analyses of such data, where absorption troughs from three important ions are measured: first, O IV and O IV* that allow us to obtain the distance of high ionization outflows from the AGN; second, Ne VIII and Mg X that are sensitive to the very high ionization phase of the outflow. Their inferred column densities, combined with those of troughs from O VI, N IV, and H I, yield two important results: 1) The outflow shows two ionization phases, where the high ionization phase carries the bulk of the material. This is similar to the situation seen in x-ray warm absorber studies. Furthermore, the low ionization phase is inferred to have a volume filling factor of 10^(-5)-10^(-6). 2) From the O IV to O IV* column density ratio, and the knowledge of the ionization parameter, we determine a distance of 3000 pc. from the outflow to the central source. Since this is a typical high ionization outflow, we can determine robust values for the mass flux and kinetic luminosity of the outflow: 40 solar masses per year and 10^45 ergs/s, respectively, where the latter is roughly equal to 1% of the bolometric luminosity. Such a large kinetic luminosity and mass flow rate measured in a typical high ionization wind suggests that quasar outflows are a major contributor to AGN feedback mechanisms.

Electrophysiological responses to feedback during the application of abstract rules.

PubMed

Walsh, Matthew M; Anderson, John R

2013-11-01

Much research focuses on how people acquire concrete stimulus-response associations from experience; however, few neuroscientific studies have examined how people learn about and select among abstract rules. To address this issue, we recorded ERPs as participants performed an abstract rule-learning task. In each trial, they viewed a sample number and two test numbers. Participants then chose a test number using one of three abstract mathematical rules they freely selected from: greater than the sample number, less than the sample number, or equal to the sample number. No one rule was always rewarded, but some rules were rewarded more frequently than others. To maximize their earnings, participants needed to learn which rules were rewarded most frequently. All participants learned to select the best rules for repeating and novel stimulus sets that obeyed the overall reward probabilities. Participants differed, however, in the extent to which they overgeneralized those rules to repeating stimulus sets that deviated from the overall reward probabilities. The feedback-related negativity (FRN), an ERP component thought to reflect reward prediction error, paralleled behavior. The FRN was sensitive to item-specific reward probabilities in participants who detected the deviant stimulus set, and the FRN was sensitive to overall reward probabilities in participants who did not. These results show that the FRN is sensitive to the utility of abstract rules and that the individual's representation of a task's states and actions shapes behavior as well as the FRN.

Measuring Medical Student Preference: A Comparison of Classroom Versus Online Instruction for Teaching Pubmed*EC

PubMed Central

Schimming, Laura M.

2008-01-01

Objective: The research analyzed evaluation data to assess medical student satisfaction with the learning experience when required PubMed training is offered entirely online. Methods: A retrospective study analyzed skills assessment scores and student feedback forms from 455 first-year medical students who completed PubMed training either through classroom sessions or an online tutorial. The class of 2006 (n = 99) attended traditional librarian-led sessions in a computer classroom. The classes of 2007 (n = 120), 2008 (n = 121), and 2009 (n = 115) completed the training entirely online through a self-paced tutorial. PubMed skills assessment scores and student feedback about the training were compared for all groups. Results: As evidenced by open-ended comments about the training, students who took the online tutorial were equally or more satisfied with the learning experience than students who attended classroom sessions, with the classes of 2008 and 2009 reporting greater satisfaction (P<0.001) than the other 2 groups. The mean score on the PubMed skills assessment (91%) was the same for all groups of students. Conclusions: Student satisfaction improved and PubMed assessment scores did not change when instruction was offered online to first-year medical students. Comments from the students who received online training suggest that the increased control and individual engagement with the web-based content led to their satisfaction with the online tutorial. PMID:18654658