Ross Sea Ecosystem Responses to Climatic Changes during the Mid-to-Late Holocene as Indicated by Bulk Stable Isotope Analyses of Antarctic Seals

NASA Astrophysics Data System (ADS)

Brault, E.; Koch, P. L.; McCarthy, M. D.; Hall, B. L.; Hoelzel, A. R.; Welch, A. J.; Nye, J. W.; Rosenfield, A. P.

2016-02-01

Substantial environmental changes occurred in the Ross Sea during the Holocene, with sea ice likely significantly increasing around 1,000 years before present (YBP). We are investigating the effects of these environmental changes on the biological community. Previous work demonstrates that the southern elephant seal (Mirounga leonina) colonies in the region began to collapse 1,000 YBP and disappeared from the area by 250 YBP. Ecosystem shifts are also evident in isotopic records. Carbon and nitrogen isotope data from Adélie penguins (Pygoscelis adeliae) differ from animals in the region today, and our isotopic values of fossil southern elephant seals are inconsistent with foraging in the current Ross Sea ecosystem. The dating of these isotopic shifts is uncertain, ranging from 1,000 to 250 YBP. We examined trends in the bulk carbon and nitrogen isotope values of Weddell (Leptonychotes weddellii) and crabeater (Lobodon carcinophagus) seals over the last 5,500 years to clarify the timing of the ecosystem shift, and further explore its effects on top predators. Crabeater seals have stable mean carbon and nitrogen isotope values through the late Holocene period, suggesting stable foraging behavior. However, isotopic data from this species are more variable before 750 YBP, indicating a more diverse foraging ecology. Weddell seals show a clear transition in isotopic values around 500 YBP, similar to that previously observed in penguins. This shift may indicate a change in Weddell seal diet (to lower trophic level prey in more recent times), a changed ecosystem (with the Ross Sea becoming less productive later in the Holocene), or both. Overall, our data shows that the ecology of top predators shifted substantially in response to changes in the Ross Sea around 1,000-500 years ago.

Targeting overall equipment efficiency for small medium enterprises with irregular production system

NASA Astrophysics Data System (ADS)

Prasetyawan, Y.; Suef, M.; Claudia, L.; Handayani, F. D.

2018-04-01

Overall Equipment Effectiveness (OEE) is widely used to measure the maturity of a production system. The company will be considered as World Class Manufacturing if it reaches more than 85% value, with near perfect value for availability, performance and quality factor. This assessment is usually taken on industries with regular production times named shift system. A typical 8 hours shift system is used in OEE measurement and performance monitoring. There are few Small to Medium Enterprise (SME) perform regular production times with shift systems, others using irregular production systems. The irregular production time in the SME production system is used because of demand fluctuations. This paper shows a quantitative analysis as a part of manufacturing system design to achieve a specific value of OEE for SME with irregular production systems, for individual businesses as well as collective business systems (some companies use the same production facilities for several processes). The results of experiments on several companies are presented, as a basis for determining the technical strategy of achieving OEE values.

Work capacity, sociodemographic and work characteristics of nurses at a university hospital.

PubMed

Hilleshein, Eunice Fabiani; Lautert, Liana

2012-01-01

This cross-sectional study evaluated the work capacity of 195 nurses at a university hospital, from a calculation of sample size with a Confidence Interval (CI) of 95%. The data was collected by means of the Work Capacity Index (WCI) instrument and analyzed by statistical analysis. 94.5% of the sample was made up of women; the average age was of 42.6 years (sd=8.5); 66.5% had partners and 76.7% were educated to post-graduate level. 36.0% worked the night shift; 28.4% the morning shift and 20.8% the afternoon shift. The average score given to work capacity was Good (41.8 points) and there was a significant correlation with pay (p-value<0.05), satisfaction with workplace (p-value=0.001) and feeling valued by the institution (p-value=0.003). The group which carried out family activities showed higher scores in the WCI compared to those who did not (p-value=0.009). The nurses presented differing sociodemographic and work aspects, with a high capacity for work.

Plate motion and the secular shift of the mean pole

NASA Technical Reports Server (NTRS)

Liu, H.; Carpenter, L.; Agreen, R. W.

1973-01-01

The global plate motion indicates that changes in the products of inertia of the earth due to tectonic plate movement may provide a secular shift of the mean pole. A mathematical procedure for calculating this shift based on the plate theory is presented. Explicit expressions were obtained for the dependence of the secular polar shift on the dimensions and locations of the plate boundaries. Numerical results show that the secular motion of the mean pole is 0.0002 sec/year in the direction of 67 W. Hence, it is deduced that the influence of the plate motion on the secular polar shift may account for 10% of the observed value.

Cultural evolution over the last 40 years in China: using the Google Ngram Viewer to study implications of social and political change for cultural values.

PubMed

Zeng, Rong; Greenfield, Patricia M

2015-02-01

Chinese people have held collectivistic values such as obligation, giving to other people, obedience and sacrifice of personal interests for thousands of years. In recent decades, China has undergone rapid economic development and urbanisation. This study investigates changing cultural values in China from 1970 to 2008 and the relationship of changing values to ecological shifts. The conceptual framework for the study was Greenfield's (2009) theory of social change and human development. Changing frequencies of contrasting Chinese words indexing individualistic or collectivistic values show that values shift along with ecological changes (urbanisation, economic development and enrollment in higher education), thereby adapting to current sociodemographic contexts. Words indexing adaptive individualistic values increased in frequency between 1970 and 2008. In contrast, words indexing less adaptive collectivistic values either decreased in frequency in this same period of time or else rose more slowly than words indexing contrasting individualistic values. © 2015 International Union of Psychological Science.

Stereospecific assignment of the asparagine and glutamine sidechain amide protons in proteins from chemical shift analysis.

PubMed

Harsch, Tobias; Schneider, Philipp; Kieninger, Bärbel; Donaubauer, Harald; Kalbitzer, Hans Robert

2017-02-01

Side chain amide protons of asparagine and glutamine residues in random-coil peptides are characterized by large chemical shift differences and can be stereospecifically assigned on the basis of their chemical shift values only. The bimodal chemical shift distributions stored in the biological magnetic resonance data bank (BMRB) do not allow such an assignment. However, an analysis of the BMRB shows, that a substantial part of all stored stereospecific assignments is not correct. We show here that in most cases stereospecific assignment can also be done for folded proteins using an unbiased artificial chemical shift data base (UACSB). For a separation of the chemical shifts of the two amide resonance lines with differences ≥0.40 ppm for asparagine and differences ≥0.42 ppm for glutamine, the downfield shifted resonance lines can be assigned to H δ21 and H ε21 , respectively, at a confidence level >95%. A classifier derived from UASCB can also be used to correct the BMRB data. The program tool AssignmentChecker implemented in AUREMOL calculates the Bayesian probability for a given stereospecific assignment and automatically corrects the assignments for a given list of chemical shifts.

Detecting giant electrocaloric properties of ferroelectric SbSI at room temperature

NASA Astrophysics Data System (ADS)

Hamad, Mahmoud A.

2013-05-01

In this work, ferroelectric SbSI shows a giant electrocaloric effect at room temperature under very low electric field shift of 0.37 kV cm-1. It is shown that the cooling ΔT per unit field MVm-1 is 2.97. This value is significantly larger, and is comparable with the value of 0.254 for PbZr0.95Ti0.05O3 thin film under electric field shift of 30 kV cm-1. Moreover, the reduction in operating temperature opens up many more possibilities and widens the potential for applications in cooling systems.

Temperature dependence and GABA modulation of (TH)triazolam binding in the rat brain

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

Earle, M.E.; Concas, A.; Wamsley, J.K.

1987-07-27

The hypnotic triazolam (TZ), a triazolobenzodiazepine displays a short physiological half life and has been used for the treatment of insomnia related to anxiety states. The authors major objectives were the direct measurement of the temperature dependence and the gamma-aminobutyric acid (GABA) effect of (TH)TZ binding in the rat brain. Saturation studies showed a shift to lower affinity with increasing temperatures (K/sub d/ = 0.27 +/- 08 nM at 0C; K/sub d/ = 1.96 +/- 0.85 nM at 37C) while the B/sub max/ values remained unchanged (1220 +/- 176 fmoles/mg protein at 0C and 1160 +/- 383 fmoles/mg protein atmore » 37C). Saturation studies of (TH)TZ binding in the presence or absence of GABA (100 M) showed a GABA-shift. At 0C the K/sub d/ values were (K/sub d/ = 0.24 +/- 0.03 nM/-GABA; K/sub d/ = 0.16 +/- 0.04/+GABA) and at 37C the K/sub d/ values were (K/sub d/ = 1.84 +/- 0.44 nM/-GABA; K/sub d/ = 0.95 +/- 0.29 nM/+GABA). In contrast to reported literature, the authors findings show that TZ interacts with benzodiazepine receptors with a temperature dependence and GABA-shift consistent with predicted behavior for benzodiazepine agonists. 20 references, 3 tables.« less

The characteristics of vibrotactile perception threshold among shipyard workers in a tropical environment.

PubMed

Tamrin, Shamsul Bahri Mohd; Jamalohdin, Mohd Nazri; Ng, Yee Guan; Maeda, Setsuo; Ali, Nurul Asyiqin Mohd

2012-01-01

The objectives of this study are to determine the prevalence of hand-arm vibration syndrome (HAVS) and the characteristics of the vibrotactile perception threshold (VPT) among users of hand-held vibrating tools working in a tropical environment. A cross sectional study was done among 47 shipyard workers using instruments and a questionnaire to determine HAVS related symptoms. The vibration acceleration magnitude was determined using a Human Vibration Meter (Maestro). A P8 Pallesthesiometer (EMSON-MAT, Poland) was used to determine the VPT of index and little finger at frequencies of 31.5 Hz and 125 Hz. The mean reference threshold shift was determined from the reference threshold shift derived from the VPT value. The results show a moderate prevalence of HAVS (49%) among the shipyard workers. They were exposed to the same high intensity level of HAVS (mean = 4.19 ± 1.94 m/s(2)) from the use of vibrating hand-held tools. The VPT values were found to be higher for both fingers and both frequencies (index, 31.5 Hz = 110.91 ± 7.36 dB, 125 Hz = 117.0 ± 10.25 dB; little, 31.5 Hz = 110.70 ± 6.75 dB, 125 Hz = 117.71 ± 10.25 dB) compared to the normal healthy population with a mean threshold shift of between 9.20 to 10.61 decibels. The frequency of 31.5 Hz had a higher percentage of positive mean reference threshold shift (index finger=93.6%, little finger=100%) compared to 125 Hz (index finger=85.1%, little finger=78.7%). In conclusion, the prevalence of HAVS was lower than those working in a cold environment; however, all workers had a higher mean VPT value compared to the normal population with all those reported as having HAVS showing a positive mean reference threshold shift of VPT value.

Differential effects of removing the glucose or saccharin components of a glucose-saccharin mixture in a successive negative contrast paradigm.

PubMed

Mitchell, Colin P; Flaherty, Charles F

2005-03-31

When rats experience an unexpected decrease in reward value, e.g., from 32% sucrose to 4% sucrose, consummatory behavior abruptly decreases to a level below control subjects that only experience the lesser reward, a phenomenon known as Successive Negative Contrast (SNC). In food deprived rats experiencing downshifts in sucrose concentration, SNC dissipates in 3-4 days, as consummatory behavior in shifted rats recovers to the level of unshifted controls. In Experiment 1 food deprived rats that were given 5 min daily access to a 2% glucose-0.15% saccharin mixture, and subsequently shifted to 2% glucose alone, displayed a dramatic SNC effect relative to rats that only received 2% glucose. This SNC effect was primarily manifested as a decrease in the number of consummatory bursts initiated. Interestingly, intake failed to recover to control levels during eight daily postshift sessions. However, in Experiment 2 subjects that were shifted from the same glucose-saccharin mixture to 0.15% saccharin alone failed to show SNC rather, intake fell to the level of control animals which only received 0.15% saccharin. The data from Experiment 1, in conjunction with previous studies utilizing non-deprived rats, quinine adulteration, or shifts from sucrose to saccharin, show that reductions in taste value can produce contrast effects, but suggest that a threshold caloric value is necessary for recovery. The data from Experiment 2 may suggest that saccharin and glucose do not contribute equally to the enhanced palatability of the mixture.

Chemometric Analysis of Gas Chromatography – Mass Spectrometry Data using Fast Retention Time Alignment via a Total Ion Current Shift Function

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

Nadeau, Jeremy S.; Wright, Bob W.; Synovec, Robert E.

2010-04-15

A critical comparison of methods for correcting severely retention time shifted gas chromatography-mass spectrometry (GC-MS) data is presented. The method reported herein is an adaptation to the Piecewise Alignment Algorithm to quickly align severely shifted one-dimensional (1D) total ion current (TIC) data, then applying these shifts to broadly align all mass channels throughout the separation, referred to as a TIC shift function (SF). The maximum shift varied from (-) 5 s in the beginning of the chromatographic separation to (+) 20 s toward the end of the separation, equivalent to a maximum shift of over 5 peak widths. Implementing themore » TIC shift function (TIC SF) prior to Fisher Ratio (F-Ratio) feature selection and then principal component analysis (PCA) was found to be a viable approach to classify complex chromatograms, that in this study were obtained from GC-MS separations of three gasoline samples serving as complex test mixtures, referred to as types C, M and S. The reported alignment algorithm via the TIC SF approach corrects for large dynamic shifting in the data as well as subtle peak-to-peak shifts. The benefits of the overall TIC SF alignment and feature selection approach were quantified using the degree-of-class separation (DCS) metric of the PCA scores plots using the type C and M samples, since they were the most similar, and thus the most challenging samples to properly classify. The DCS values showed an increase from an initial value of essentially zero for the unaligned GC-TIC data to a value of 7.9 following alignment; however, the DCS was unchanged by feature selection using F-Ratios for the GC-TIC data. The full mass spectral data provided an increase to a final DCS of 13.7 after alignment and two-dimensional (2D) F-Ratio feature selection.« less

Inverse effects of flowing phase-shift nanodroplets and lipid-shelled microbubbles on subsequent cavitation during focused ultrasound exposures.

PubMed

Zhang, Siyuan; Cui, Zhiwei; Xu, Tianqi; Liu, Pan; Li, Dapeng; Shang, Shaoqiang; Xu, Ranxiang; Zong, Yujin; Niu, Gang; Wang, Supin; He, Xijing; Wan, Mingxi

2017-01-01

This paper compared the effects of flowing phase-shift nanodroplets (NDs) and lipid-shelled microbubbles (MBs) on subsequent cavitation during focused ultrasound (FUS) exposures. The cavitation activity was monitored using a passive cavitation detection method as solutions of either phase-shift NDs or lipid-shelled MBs flowed at varying velocities through a 5-mm diameter wall-less vessel in a transparent tissue-mimicking phantom when exposed to FUS. The intensity of cavitation for the phase-shift NDs showed an upward trend with time and cavitation for the lipid-shelled MBs grew to a maximum at the outset of the FUS exposure followed by a trend of decreases when they were static in the vessel. Meanwhile, the increase of cavitation for the phase-shift NDs and decrease of cavitation for the lipid-shelled MBs had slowed down when they flowed through the vessel. During two discrete identical FUS exposures, while the normalized inertial cavitation dose (ICD) value for the lipid-shelled MB solution was higher than that for the saline in the first exposure (p-value <0.05), it decreased to almost the same level in the second exposure. For the phase-shift NDs, the normalized ICD was 0.71 in the first exposure and increased to 0.97 in the second exposure. At a low acoustic power, the normalized ICD values for the lipid-shelled MBs tended to increase with increasing velocities from 5 to 30cm/s (r>0.95). Meanwhile, the normalized ICD value for the phase-shift NDs was 0.182 at a flow velocity of 5cm/s and increased to 0.188 at a flow velocity of 15cm/s. As the flow velocity increased to 20cm/s, the normalized ICD was 0.185 and decreased to 0.178 at a flow velocity of 30cm/s. At high acoustic power, the normalized ICD values for both the lipid-shelled MBs and the phase-shift NDs increased with increasing flow velocities from 5 to 30cm/s (r>0.95). The effects of the flowing phase-shift NDs vaporized into gas bubbles as cavitation nuclei on the subsequent cavitation were inverse to those of the flowing lipid-shelled MBs destroyed after focused ultrasound exposures. Copyright © 2016 Elsevier B.V. All rights reserved.

The effect of shift rotation on variations of cortisol, fatigue and sleep in sound engineers.

PubMed

Vangelova, Katia

2008-10-01

The aim was to study the effect of rotation direction on the time-of-day variations of cortisol, fatigue and sleep in sound engineers broadcasting in a life show. The salivary cortisol and ratings of stress, sleepiness and fatigue were followed at three hour intervals in 25 sound engineers: 13 working very fast forward-rotating shifts and 12 working very fast backward-rotating shifts. Cortisol was assessed with radioimmunological kits. The participants reported for stress symptoms and filled sleep diary. Cortisol retained the typical diurnal pattern. The rotation direction interacted with the shift significantly and as a result higher cortisol values during the morning and night shifts in the backward rotating group were found as well as worse quality of sleep. Higher salivary cortisol during morning and night shifts and worse quality of sleep in engineers working very fast backward-rotating shifts may be an indication for insufficient recovery.

Geographic variation in Pacific herring growth in response to regime shifts in the North Pacific Ocean

NASA Astrophysics Data System (ADS)

Ito, Shin-ichi; Rose, Kenneth A.; Megrey, Bernard A.; Schweigert, Jake; Hay, Douglas; Werner, Francisco E.; Aita, Maki Noguchi

2015-11-01

Pacific herring populations at eight North Pacific Rim locations were simulated to compare basin-wide geographic variations in age-specific growth due to environmental influences on marine productivity and population-specific responses to regime shifts. Temperature and zooplankton abundance from a three-dimensional lower-trophic ecosystem model (NEMURO: North Pacific Ecosystem Model for Understanding Regional Oceanography) simulation from 1948 to 2002 were used as inputs to a herring bioenergetics growth model. Herring populations from California, the west coast of Vancouver Island (WCVI), Prince William Sound (PWS), Togiak Alaska, the western Bering Sea (WBS), the Sea of Okhotsk (SO), Sakhalin, and Peter the Great Bay (PGB) were examined. The half-saturation coefficients of herring feeding were calibrated to climatological conditions at each of the eight locations to reproduce averaged size-at-age data. The depth of averaging used for water temperature and zooplankton, and the maximum consumption rate parameter, were made specific to each location. Using the calibrated half-saturation coefficients, the 1948-2002 period was then simulated using daily values of water temperature and zooplankton densities interpolated from monthly model output. To detect regime shifts in simulated temperatures, zooplankton and herring growth rates, we applied sequential t-test analyses on the 54 years of hindcast simulation values. The detected shifts of herring age-5 growth showed closest match (69%) to the regime shift years (1957/58, 1970/71, 1976/77, 1988/89, 1998/99). We explored relationships among locations using cluster and principal component analyses. The first principal component of water temperature showed good correspondence to the Pacific Decadal Oscillation and all zooplankton groups showed a pan-Pacific decrease after the 1976/77 regime shift. However, the first principal component of herring growth rate showed decreased growth at the SO, PWS, WCVI and California locations and increased growth at the Sakhalin, WBS and Togiak locations after 1977. The SO location belonged to the same cluster as the location in with the eastern North Pacific. The calibrated half-saturation coefficients affected the degree to which growth was sensitive to interannual variation in water temperature versus zooplankton. For example, the half-saturation values for the SO location resulted in very efficient feeding that shifted the sensitivity of herring growth from food to temperature. The model results demonstrate how geographic specificity of bioenergetics parameters, coupled with location-specific variation in temperature and food, can combine to determine local and regional responses of fish growth to climate forcing.

Temperature-Dependent Energy Gap Shift and Thermally Activated Transition in Multilayer CdTe/ZnTe Quantum Dots.

PubMed

Man, Minh Tan; Lee, Hong Seok

2015-10-01

We investigated the influence of growth conditions on carrier dynamics in multilayer CdTe/ZnTe quantum dots (QDs) by monitoring the temperature dependence of the photoluminescence emission energy. The results were analyzed using the empirical Varshni and O'Donnell relations for temperature variation of the energy gap shift. Best fit values showed that the thermally activated transition between two different states occurs due to band low-temperature quenching with values separated by 5.0-6.5 meV. The addition of stack periods in multilayer CdTe/ZnTe QDs plays an important role in the energy gap shift, where the exciton binding energy is enhanced, and, conversely, the exciton-phonon coupling strength is suppressed with an average energy of 19.3-19.8 meV.

Blind phase error suppression for color-encoded digital fringe projection profilometry

NASA Astrophysics Data System (ADS)

Ma, S.; Zhu, R.; Quan, C.; Li, B.; Tay, C. J.; Chen, L.

2012-04-01

Color-encoded digital fringe projection profilometry (CDFPP) has the advantage of fast speed, non-contact and full-field testing. It is one of the most important dynamic three-dimensional (3D) profile measurement techniques. However, due to factors such as color cross-talk and gamma distortion of electro-optical devices, phase errors arise when conventional phase-shifting algorithms with fixed phase shift values are utilized to retrieve phases. In this paper, a simple and effective blind phase error suppression approach based on isotropic n-dimensional fringe pattern normalization (INFPN) and carrier squeezing interferometry (CSI) is proposed. It does not require pre-calibration for the gamma and color-coupling coefficients or the phase shift values. Simulation and experimental works show that our proposed approach is able to effectively suppress phase errors and achieve accurate measurement results in CDFPP.

Cortisol, reaction time test and health among offshore shift workers.

PubMed

Harris, Anette; Waage, Siri; Ursin, Holger; Hansen, Ase Marie; Bjorvatn, Bjørn; Eriksen, Hege R

2010-10-01

The stress hormone cortisol shows a pronounced endogenous diurnal rhythm, which is affected by the sleep/wake cycle, meals and activity. Shift work and especially night work disrupts the sleep/wake cycle and causes a desynchronization of the natural biological rhythms. Therefore, different shift schedules may have different impact on performance at work and health. The purpose was to study if health, reaction time, and the cortisol rhythm were negatively affected when a group of shift workers changed their work schedule from ordinary day-night shift (fixed shift) to "swing shift". 19 healthy workers on a Norwegian oil rig participated in the study. They worked 2 weeks offshore followed by 4 weeks off work. The ordinary schedule consisted of 12-h day shift and 12-h night shift every other work period (14 days or nights=fixed shift). "Swing shift" involved 1 week of night shift, followed by 1 week of day shift during the work period. All participants worked ordinary day-night shift when baseline data were collected (questionnaires, saliva cortisol, and reaction time during work). After collection of baseline data the workers changed their work schedule to "swing shift", for every working period, and 9 months later the same data were collected. "Swing shift" did not give any negative health effects or any negative changes in reaction time during the day they shifted from night work to day work. Personnel adapted to night shift within a week regardless of schedule, but recovery from night shift took longer time. During swing shift the cortisol rhythm went back towards a normal rhythm in the second week, but it was not returned completely to normal values when they returned home for the 4 weeks off period. However, the cortisol rhythms were readapted to normal values after 1 week at home. For personnel returning home directly from 14 consecutive night shifts, cortisol adaptation was not complete after 1 week at home. We found no increase in health complaints from swing shift or reaction time in the shift from night to day work. Recovery from night shift takes longer time. Copyright © 2010 Elsevier Ltd. All rights reserved.

Blue and red shifted temperature dependence of implicit phonon shifts in graphene

NASA Astrophysics Data System (ADS)

Mann, Sarita; Jindal, V. K.

2017-07-01

We have calculated the implicit shift for various modes of frequency in a pure graphene sheet. Thermal expansion and Grüneisen parameter which are required for implicit shift calculation have already been studied and reported. For this calculation, phonon frequencies are obtained using force constants derived from dynamical matrix calculated using VASP code where the density functional perturbation theory (DFPT) is used in interface with phonopy software. The implicit phonon shift shows an unusual behavior as compared to the bulk materials. The frequency shift is large negative (red shift) for ZA and ZO modes and the value of negative shift increases with increase in temperature. On the other hand, blue shift arises for all other longitudinal and transverse modes with a similar trend of increase with increase in temperature. The q dependence of phonon shifts has also been studied. Such simultaneous red and blue shifts in transverse or out plane modes and surface modes, respectively leads to speculation of surface softening in out of plane direction in preference to surface melting.

Creating value for participants in multistakeholder alliances: The shifting importance of leadership and collaborative decision-making over time.

PubMed

D'Aunno, Thomas; Alexander, Jeffrey A; Jiang, Lan

Multistakeholder alliances that bring together diverse organizations to work on health-related issues are playing an increasingly prominent role in the U.S. health care system. Prior research shows that collaborative decision-making and effective leadership are related to members' perceptions of value for their participation in alliances. Yet, we know little about how collaborative decision-making and leadership might matter over time in multistakeholder alliances. The aim of this study was to advance understanding of the role of collaborative decision-making and leadership in individuals' assessments of the benefits and costs of their participation in multistakeholder alliances over time. We draw on data collected from three rounds of surveys of alliance members (2007-2012) who participated in the Robert Wood Johnson Foundation's Aligning Forces for Quality program. Results from regression analyses indicate that individuals' perceptions of value for their participation in alliances shift over time: Perceived value is higher with collaborative decision-making when alliances are first formed and higher with more effective leadership as time passes after alliance formation. Leaders of multistakeholder alliances may need to vary their behavior over time, shifting their emphasis from inclusive decision-making to task achievement.

The interprofessional socialization and valuing scale: a tool for evaluating the shift toward collaborative care approaches in health care settings.

PubMed

King, Gillian; Shaw, Lynn; Orchard, Carole A; Miller, Stacy

2010-01-01

There is a need for tools by which to evaluate the beliefs, behaviors, and attitudes that underlie interprofessional socialization and collaborative practice in health care settings. This paper introduces the Interprofessional Socialization and Valuing Scale (ISVS), a 24-item self-report measure based on concepts in the interprofessional literature concerning shifts in beliefs, behaviors, and attitudes that underlie interprofessional socialization. The ISVS was designed to measure the degree to which transformative learning takes place, as evidenced by changed assumptions and worldviews, enhanced knowledge and skills concerning interprofessional collaborative teamwork, and shifts in values and identities. The scales of the ISVS were determined using principal components analysis. The principal components analysis revealed three scales accounting for approximately 49% of the variance in responses: (a) Self-Perceived Ability to Work with Others, (b) Value in Working with Others, and (c) Comfort in Working with Others. These empirically derived scales showed good fit with the conceptual basis of the measure. The ISVS provides insight into the abilities, values, and beliefs underlying socio-cultural aspects of collaborative and authentic interprofessional care in the workplace, and can be used to evaluate the impact of interprofessional education efforts, in house team training, and workshops.

Impact Tests of Welded Joints

DTIC Science & Technology

1936-04-01

indicate that good welds by these two last named processes give excellent impact results. Welds subjected to extremely low or high temperature merit...variation with temperature of the ratio of shear to tensile stress developed in the Izod or Charpy test, falls from a high to an exceedingly low value...and Larsen also showed that high nitrogen or oxygen content shifted the "zone of transition" to higher temperatures , and that normalizing shifted the

Learned value and object perception: Accelerated perception or biased decisions?

PubMed

Rajsic, Jason; Perera, Harendri; Pratt, Jay

2017-02-01

Learned value is known to bias visual search toward valued stimuli. However, some uncertainty exists regarding the stage of visual processing that is modulated by learned value. Here, we directly tested the effect of learned value on preattentive processing using temporal order judgments. Across four experiments, we imbued some stimuli with high value and some with low value, using a nonmonetary reward task. In Experiment 1, we replicated the value-driven distraction effect, validating our nonmonetary reward task. Experiment 2 showed that high-value stimuli, but not low-value stimuli, exhibit a prior-entry effect. Experiment 3, which reversed the temporal order judgment task (i.e., reporting which stimulus came second), showed no prior-entry effect, indicating that although a response bias may be present for high-value stimuli, they are still reported as appearing earlier. However, Experiment 4, using a simultaneity judgment task, showed no shift in temporal perception. Overall, our results support the conclusion that learned value biases perceptual decisions about valued stimuli without speeding preattentive stimulus processing.

DFT calculations of graphene monolayer in presence of Fe dopant and vacancy

NASA Astrophysics Data System (ADS)

Ostovari, Fatemeh; Hasanpoori, Marziyeh; Abbasnejad, Mohaddeseh; Salehi, Mohammad Ali

2018-07-01

In the present work, the effects of Fe doping and vacancies on the electronic, magnetic and optical properties of graphene are studied by density functional theory based calculations. The conductive behavior is revealed for the various defected graphene by means of electronic density of states. However, defected structures show different magnetic and optical properties compared to those of pure one. The ferromagnetic phase is the most probable phase by substituting Fe atoms and vacancies at AA sublattice of graphene. The optical properties of impure graphene differ from pure graphene under illumination with parallel polarization of electric field, whereas for perpendicular polarization it remains unchanged. In presence of defect and under parallel polarization of light, the static dielectric constant rises strongly and the maximum peak of Im ε(ω) shows red shift relative to pure graphene. Moreover, the maximum absorption peak gets broaden in the visible to infrared region at the same condition and the magnitude and related energy of peaks shift to higher value in the EELS spectra. Furthermore, the results show that the maximum values of refractive index and reflectivity spectra increase rapidly and represent the red and blue shifts; respectively. Generally; substituting the C atom with Fe has more effect on magnetic and optical properties relative to the C vacancies.

Research on high Tc superconducting compounds

NASA Technical Reports Server (NTRS)

Oliver, Frederick W. (Principal Investigator)

1996-01-01

Mossbauer research using the 21.54 kev resonance radiation of Eu-151 on the high temperature superconductors Bi(2)Ca(0.5)Eu(0.5)Sr(2)CU2O(x), and EuBa(2)CU(3)O(7-x) is performed. For the Bismuth compound the Mossbauer measurements gave a weak signal at room temperature but improved at lower temperatures. Experimental data indicated that europium is located at only one crystallographic site. Isomer shift measurements were .69 + 0.02 mm/s with respect to EuF(3). The linewidth at room temperature was found to be 2.54 mm/s. This value falls within the values observed by other researchers on Eu based 1,2,3 high-Tc compounds. Our results also show the Eu to be trivalent with no trace of divalent europium present. Superconducting europium based 1,2,3 compounds were prepared and measurements completed. Our results show the Eu to be trivalent with no trace of divalent europium present. These compounds had an average isomer shift of .73 mm/s +/- O.02 for all samples made. One of these was irradiated with 3.5 X 10(exp 16) neutrons and a comparison made of the Mossbauer parameters for the irradiated and non-irradiated samples. Experimental results showed no difference between linewidths but a measurable effect was seen for the isomer shift.

Linking social change and developmental change: shifting pathways of human development.

PubMed

Greenfield, Patricia M

2009-03-01

P. M. Greenfield's new theory of social change and human development aims to show how changing sociodemographic ecologies alter cultural values and learning environments and thereby shift developmental pathways. Worldwide sociodemographic trends include movement from rural residence, informal education at home, subsistence economy, and low-technology environments to urban residence, formal schooling, commerce, and high-technology environments. The former ecology is summarized by the German term Gemeinschaft ("community") and the latter by the German term Gesellschaft ("society"; Tönnies, 1887/1957). A review of empirical research demonstrates that, through adaptive processes, movement of any ecological variable in a Gesellschaft direction shifts cultural values in an individualistic direction and developmental pathways toward more independent social behavior and more abstract cognition--to give a few examples of the myriad behaviors that respond to these sociodemographic changes. In contrast, the (much less frequent) movement of any ecological variable in a Gemeinschaft direction is predicted to move cultural values and developmental pathways in the opposite direction. In conclusion, sociocultural environments are not static either in the developed or the developing world and therefore must be treated dynamically in developmental research.

Valuing shifts in the distribution of visibility in national parks and wilderness areas in the United States.

PubMed

Boyle, Kevin J; Paterson, Robert; Carson, Richard; Leggett, Christopher; Kanninen, Barbara; Molenar, John; Neumann, James

2016-05-15

Environmental regulations often have the objective of eliminating the lower tail of an index of environmental quality. That part of the distribution of environmental quality moves somewhere above a threshold and where in the original distribution it moves is a function of the control strategy chosen. This paper provides an approach for estimating the economic benefits of different distributional changes as the worst environmental conditions are removed. The proposed approach is illustrated by examining shifts in visibility at Class I visibility areas (National Parks and wilderness areas) that would occur with implementation of the U.S. Environmental Protection Agency's Regional Haze Program. In this application we show that people value shifts in the distribution of visibility and place a higher value on the removal of a low visibility day than on the addition of a high visibility day. We found that respondents would pay about $120 per year in the Southeast U.S. and about $80 per year in the Southwest U.S. for improvement programs that remove the 20% worst visibility days. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Tumor segmentation of brain MRI with adaptive bandwidth mean shift].

PubMed

Hou, Xiaowen; Liu, Qi

2014-10-01

In order to get the adaptive bandwidth of mean shift to make the tumor segmentation of brain magnetic resonance imaging (MRI) to be more accurate, we in this paper present an advanced mean shift method. Firstly, we made use of the space characteristics of brain image to eliminate the impact on segmentation of skull; and then, based on the characteristics of spatial agglomeration of different tissues of brain (includes tumor), we applied edge points to get the optimal initial mean value and the respectively adaptive bandwidth, in order to improve the accuracy of tumor segmentation. The results of experiment showed that, contrast to the fixed bandwidth mean shift method, the method in this paper could segment the tumor more accurately.

SU-E-J-32: Calypso(R) and Laser-Based Localization Systems Comparison for Left-Sided Breast Cancer Patients Using Deep Inspiration Breath Hold

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

Robertson, S; Kaurin, D; Sweeney, L

2014-06-01

Purpose: Our institution uses a manual laser-based system for primary localization and verification during radiation treatment of left-sided breast cancer patients using deep inspiration breath hold (DIBH). This primary system was compared with sternum-placed Calypso(R) beacons (Varian Medical Systems, CA). Only intact breast patients are considered for this analysis. Methods: During computed tomography (CT) simulation, patients have BB and Calypso(R) surface beacons positioned sternally and marked for free-breathing and DIBH CTs. During dosimetry planning, BB longitudinal displacement between free breathing and DIBH CT determines laser mark (BH mark) location. Calypso(R) beacon locations from the DIBH CT are entered at themore » Tracking Station. During Linac simulation and treatment, patients inhale until the cross-hair and/or lasers coincide with the BH Mark, which can be seen using our high quality cameras (Pelco, CA). Daily Calypso(R) displacement values (difference from the DIBH-CT-based plan) are recorded.The displacement mean and standard deviation was calculated for each patient (77 patients, 1845 sessions). An aggregate mean and standard deviation was calculated weighted by the number of patient fractions.Some patients were shifted based on MV ports. A second data set was calculated with Calypso(R) values corrected by these shifts. Results: Mean displacement values indicate agreement within 1±3mm, with improvement for shifted data (Table). Conclusion: Both unshifted and shifted data sets show the Calypso(R) system coincides with the laser system within 1±3mm, demonstrating either localization/verification system will Resultin similar clinical outcomes. Displacement value uncertainty unilaterally reduces when shifts are taken into account.« less

Influence of impression technique and material on the accuracy of multiple implant impressions.

PubMed

Wöstmann, Bernd; Rehmann, Peter; Balkenhol, Markus

2008-01-01

This study aimed to analyze the influence of impression technique (pick-up versus reposition) and material on the accuracy of the working cast. Sixty impressions were made with 3 materials from a master cast with 4 XiVE implants. The changes in the implant axis direction, rotation, and 3-dimensional shift were assessed. The pick-up technique showed significantly (P < .05, U test) lower values for axis direction and 3D shift but higher values for rotation than the reposition technique. The differences between the materials were not significant (P > .05, H test). It can be concluded that the impression technique-in contrast to the impression material-has a significant influence on transfer accuracy.

Exploring spiritual value in earth science concept through learning using chain till unanswered questions

NASA Astrophysics Data System (ADS)

Johan, Henny; Suhandi, Andi; Samsudin, Ahmad; Ratna Wulan, Ana

2017-08-01

Now days, the youth's moral decline is an urgent problem in our country. Natural science especially earth and space science learning is potential to insert spirituality value in its learning activities. The aim of this study is to explore concept of planet earth to embed spirituality attitude through earth science learning. Interactive conceptual learning model using chain till unanswered questions (CTUQ) with help visualizations was implemented in this study. 23 pre-service physics teacher in Bengkulu, Indonesia participated in this study. A sixth indicator of spiritual aspect about awareness of divinity were used to identify the shifted of students' spirituality. Quasi experimental research design had been utilized to implement the learning model. The data were collected using a questionnaire in pretest and posttest. Open ended question was given at post-test only. Questionnaire was analyzed quantitative while open ended question was analyzed qualitatively. The results show that after implementation student's spiritual shifted to be more awareness of divinity. Students' response at scale 10 increased been 97.8% from 87.5% of total responses. Based on analysis of open ended question known that the shifted was influenced by spiritual value inserted in concepts, CTUQ, and media visualization used to show unobservable earth phenomenon during learning activities. It can be concluded that earth science concepts can be explored to embed spiritual aspect.

Examining the use of comparative and cost-effectiveness analyses in radiology.

PubMed

Goehler, Alexander; Gazelle, G Scott

2014-11-01

This article explores key principles of comparative effectiveness analysis--in particular, how radiologic comparative and cost-effectiveness studies differ from other clinical trials. Exemplary studies are reviewed to show how comparative effectiveness has been implemented in radiology and how future studies might be conducted. Finally, the article closes with a discussion of several additional key themes relevant to quality and value in clinical radiology going forward. Comparative effectiveness is likely to require a paradigm shift in thinking within the discipline. For new radiologic applications to be accepted, we will need to show at least a significant change in treatment planning and at best a meaningful change in patient outcomes. This shift will require a forward-thinking approach to robust evidence generation for new imaging modalities or indications and the inclusion of other modes of value demonstration such as clinical decision support and intelligent data mining.

Hepatic fat quantification using automated six-point Dixon: Comparison with conventional chemical shift based sequences and computed tomography.

PubMed

Shimizu, Kie; Namimoto, Tomohiro; Nakagawa, Masataka; Morita, Kosuke; Oda, Seitaro; Nakaura, Takeshi; Utsunomiya, Daisuke; Yamashita, Yasuyuki

To compare automated six-point Dixon (6-p-Dixon) MRI comparing with dual-echo chemical-shift-imaging (CSI) and CT for hepatic fat fraction in phantoms and clinical study. Phantoms and fifty-nine patients were examined both MRI and CT for quantitative fat measurements. In phantom study, linear regression between fat concentration and 6-p-Dixon showed good agreement. In clinical study, linear regression between 6-p-Dixon and dual-echo CSI showed good agreement. CT attenuation value was strongly correlated with 6-p-Dixon (R 2 =0.852; P<0.001) and dual-echo CSI (R 2 =0.812; P<0.001). Automated 6-p-Dixon and dual-echo CSI were accurate correlation with CT attenuation value of liver parenchyma. 6-p-Dixon has the potential for automated hepatic fat quantification. Copyright © 2017 Elsevier Inc. All rights reserved.

Development of a Simulink Library for the Design, Testing and Simulation of Software Defined GPS Radios. With Application to the Development of Parallel Correlator Structures

DTIC Science & Technology

2014-05-01

function Value = Select_Element(Index,Signal) %# eml Value = Signal(Index); Code Listing 1 Code for Selector Block 12 | P a g e 4.3...code for the Simulink function shiftedSignal = fcn(signal,Shift) %# eml shiftedSignal = circshift(signal,Shift); Code Listing 2 Code for CircShift

Midline Shift Threshold Value for Hemiparesis in Chronic Subdural Hematoma.

PubMed

Juković, Mirela F; Stojanović, Dejan B

2015-01-01

Chronic subdural hematoma (CSDH) has a variety of clinical presentations, with numerous neurological symptoms and signs. Hemiparesis is one of the leading signs that potentially indicates CSDH. Purpose of this study was to determine the threshold (cut-off) value of midsagittal line (MSL) shift after which hemiparesis is likely to appear. The study evaluated 83 patients with 53 unilateral and 30 bilateral CSDHs in period of three years. Evaluated computed tomography (CT) findings in patients with CSDH were diameter of the hematoma and midsagittal line shift, measured on non-contrast CT scan in relation with occurrence of hemiparesis. Threshold values of MSL shift for both types of CSDHs were obtained as maximal (equal) sensitivity and specificity (intersection of the curves). MSL is a good predictor for hemiparesis occurrence (total sample, AUROC 0.75, p=0.0001). Unilateral and bilateral CSDHs had different threshold values of the MSL for hemiparesis development. Results suggested that in unilateral CSDH the threshold values of MSL could be at 10 mm (AUROC=0.65; p=0.07). For bilateral CSDH the threshold level of MSL shift was 4.5 mm (AUROC=0.77; p=0.01). Our study pointed on the phenomenon that midsagittal line shift can predict hemiparesis occurrence. Hemiparesis in patients with bilateral CSDH was more related to midsagittal line shift compared with unilateral CSDH. When value of midsagittal line shift exceed the threshold level, hemiparesis occurs with certain probability.

On The Stark Shift of Ar II 472.68 nm Spectral Line

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

Mijatovic, Z.; Gajo, T.; Vujicic, B.

The Stark shift of Ar II 472.68 nm (transition 4s2P - 4p2D deg. ) spectral lines emitted from T-tube plasmas was considered. The electron density ranged from (1.63-2.2){center_dot}1023 m-3 and was determined using laser interferometry. The plasma temperature, derived from the Gaussian part of recorded line profiles was found to be in the range (15000-43300) K. Experimental shifts were compared to theoretical values obtained from the semiempirical formula [M. S. Dimitrijevic and N. Konjevic, J. Quant. Spectrosc. Radiat. Transfer 24, 451 (1980)]. This comparison showed good agreement between experimental results and theory.

A coarse-to-fine kernel matching approach for mean-shift based visual tracking

NASA Astrophysics Data System (ADS)

Liangfu, L.; Zuren, F.; Weidong, C.; Ming, J.

2009-03-01

Mean shift is an efficient pattern match algorithm. It is widely used in visual tracking fields since it need not perform whole search in the image space. It employs gradient optimization method to reduce the time of feature matching and realize rapid object localization, and uses Bhattacharyya coefficient as the similarity measure between object template and candidate template. This thesis presents a mean shift algorithm based on coarse-to-fine search for the best kernel matching. This paper researches for object tracking with large motion area based on mean shift. To realize efficient tracking of such an object, we present a kernel matching method from coarseness to fine. If the motion areas of the object between two frames are very large and they are not overlapped in image space, then the traditional mean shift method can only obtain local optimal value by iterative computing in the old object window area, so the real tracking position cannot be obtained and the object tracking will be disabled. Our proposed algorithm can efficiently use a similarity measure function to realize the rough location of motion object, then use mean shift method to obtain the accurate local optimal value by iterative computing, which successfully realizes object tracking with large motion. Experimental results show its good performance in accuracy and speed when compared with background-weighted histogram algorithm in the literature.

Comparison of experimental and DFT-calculated NMR chemical shifts of 2-amino and 2-hydroxyl substituted phenyl benzimidazoles, benzoxazoles and benzothiazoles in four solvents using the IEF-PCM solvation model.

PubMed

Pierens, Gregory K; Venkatachalam, T K; Reutens, David C

2016-04-01

A comparative study of experimental and calculated NMR chemical shifts of six compounds comprising 2-amino and 2-hydroxy phenyl benzoxazoles/benzothiazoles/benzimidazoles in four solvents is reported. The benzimidazoles showed interesting spectral characteristics, which are discussed. The proton and carbon chemical shifts were similar for all solvents. The largest chemical shift deviations were observed in benzene. The chemical shifts were calculated with density functional theory using a suite of four functionals and basis set combinations. The calculated chemical shifts revealed a good match to the experimentally observed values in most of the solvents. The mean absolute error was used as the primary metric. The use of an additional metric is suggested, which is based on the order of chemical shifts. The DP4 probability measures were also used to compare the experimental and calculated chemical shifts for each compound in the four solvents. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Ventilatory function in rubber processing workers: acute changes over the workshift.

PubMed

Governa, M; Comai, M; Valentino, M; Antonicelli, L; Rinaldi, F; Pisani, E

1987-02-01

When considering rubber tyre manufacturing from an occupational health viewpoint, three areas may be identified in which exposure to respirable materials are potentially harmful: the processing, curing, and talc areas. A study of the ventilatory function of the entire work force employed in the processing area in a rubber tyre manufacturing plant was undertaken to determine whether an acute reduction in lung function occurs over the course of their working shift (the plant worked a three shift system) and whether a chronic exposure to the occupational airborne contaminants causes permanent changes in lung function. The ventilatory function was measured at the worksite at the beginning and immediately after the end of the workshift. No evidence of chronic obstructive pulmonary disease was found and in most cases no significant decline in FEV1 was observed. Only one of the 79 individuals showed a moderate obstruction, measured by the ratio FEV1/FVC which gave the value of 0.55, with no variation over the shift. For non-smokers, the FVC, FEV1, and FEF25-75% were lower in those exposed for more than five years than in those exposed for five years or less. A similar pattern was also observed in the FVC and FEV1 of the smokers. None of these differences was statistically significant. Within each exposure group the pulmonary function of the smokers was lower than that of the non-smokers, but the only significant difference was found in the values of FEF25-75%. Only one man showed a decline in the FEV1/FVC ratio over the shift, but during each shift, a decrease in all the lung function tests was observed. The decrease was smallest during the first of the three shifts. These results are thought to support the hypothesis that there are acute adverse effects over an eight hour shift. Further investigations are needed to discover whether these acute changes in lung function result from a chemical stimulation or irritant receptors in the airways.

Lateral variations in vegetation in the Himalaya since the Miocene and implications for climate evolution

NASA Astrophysics Data System (ADS)

Vögeli, Natalie; Najman, Yani; van der Beek, Peter; Huyghe, Pascale; Wynn, Peter M.; Govin, Gwladys; van der Veen, Iris; Sachse, Dirk

2017-08-01

The Himalaya has a major influence on global and regional climate, in particular on the Asian monsoon system. The foreland basin of the Himalaya contains a record of tectonics and paleoclimate since the Miocene. Previous work on the evolution of vegetation and climate has focused on the central and western Himalaya, where a shift from C3 to C4 vegetation has been observed at ∼7 Ma and linked to increased seasonality, but the climatic evolution of the eastern part of the orogen is less well understood. In order to track vegetation as a marker of monsoon intensity and seasonality, we analyzed δ13 C and δ18 O values of soil carbonate and associated δ13 C values of bulk organic carbon from previously dated sedimentary sections exposing the syn-orogenic detrital Dharamsala and Siwalik Groups in the west, and, for the first time, the Siwalik Group in the east of the Himalayan foreland basin. Sedimentary records span from 20 to 1 Myr in the west (Joginder Nagar, Jawalamukhi, and Haripur Kolar sections) and from 13 to 1 Myr in the east (Kameng section), respectively. The presence of soil carbonate in the west and its absence in the east is a first indication of long-term lateral climatic variation, as soil carbonate requires seasonally arid conditions to develop. δ13 C values in soil carbonate show a shift from around -10‰ to -2‰ at ∼7 Ma in the west, which is confirmed by δ13 C analyses on bulk organic carbon that show a shift from around -23‰ to -19‰ at the same time. Such a shift in isotopic values is likely to be associated with a change from C3 to C4 vegetation. In contrast, δ13 C values of bulk organic carbon remain at ∼ - 23 ‰ in the east. Thus, our data show that the current east-west variation in climate was established at 7 Ma. We propose that the regional change towards a more seasonal climate in the west is linked to a decrease of the influence of the Westerlies, delivering less winter precipitation to the western Himalaya, while the east remained annually humid due to its proximity to the monsoonal moisture source.

Nutrition and health in hotel staff on different shift patterns.

PubMed

Seibt, R; Süße, T; Spitzer, S; Hunger, B; Rudolf, M

2015-08-01

Limited research is available that examines the nutritional behaviour and health of hotel staff working alternating and regular shifts. To analyse the nutritional behaviour and health of employees working in alternating and regular shifts. The study used an ex post facto cross-sectional analysis to compare the nutritional behaviour and health parameters of workers with alternating shifts and regular shift workers. Nutritional behaviour was assessed with the Food Frequency Questionnaire. Body dimensions (body mass index, waist hip ratio, fat mass and active cell mass), metabolic values (glucose, triglyceride, total cholesterol and low- and high-density lipoprotein), diseases and health complaints were included as health parameters. Participants worked in alternating (n = 53) and regular shifts (n = 97). The average age of subjects was 35 ± 10 years. There was no significant difference in nutritional behaviour, most surveyed body dimensions or metabolic values between the two groups. However, alternating shift workers had significantly lower fat mass and higher active cell mass but nevertheless reported more pronounced health complaints. Sex and age were also confirmed as influencing the surveyed parameters. Shift-dependent nutritional problems were not conspicuously apparent in this sample of hotel industry workers. Health parameters did not show significantly negative attributes for alternating shift workers. Conceivably, both groups could have the same level of knowledge on the health effects of nutrition and comparable opportunities to apply this. Further studies on nutritional and health behaviour in the hotel industry are necessary in order to create validated screening programmes. © The Author 2015. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Protein structure refinement using a quantum mechanics-based chemical shielding predictor.

PubMed

Bratholm, Lars A; Jensen, Jan H

2017-03-01

The accurate prediction of protein chemical shifts using a quantum mechanics (QM)-based method has been the subject of intense research for more than 20 years but so far empirical methods for chemical shift prediction have proven more accurate. In this paper we show that a QM-based predictor of a protein backbone and CB chemical shifts (ProCS15, PeerJ , 2016, 3, e1344) is of comparable accuracy to empirical chemical shift predictors after chemical shift-based structural refinement that removes small structural errors. We present a method by which quantum chemistry based predictions of isotropic chemical shielding values (ProCS15) can be used to refine protein structures using Markov Chain Monte Carlo (MCMC) simulations, relating the chemical shielding values to the experimental chemical shifts probabilistically. Two kinds of MCMC structural refinement simulations were performed using force field geometry optimized X-ray structures as starting points: simulated annealing of the starting structure and constant temperature MCMC simulation followed by simulated annealing of a representative ensemble structure. Annealing of the CHARMM structure changes the CA-RMSD by an average of 0.4 Å but lowers the chemical shift RMSD by 1.0 and 0.7 ppm for CA and N. Conformational averaging has a relatively small effect (0.1-0.2 ppm) on the overall agreement with carbon chemical shifts but lowers the error for nitrogen chemical shifts by 0.4 ppm. If an amino acid specific offset is included the ProCS15 predicted chemical shifts have RMSD values relative to experiments that are comparable to popular empirical chemical shift predictors. The annealed representative ensemble structures differ in CA-RMSD relative to the initial structures by an average of 2.0 Å, with >2.0 Å difference for six proteins. In four of the cases, the largest structural differences arise in structurally flexible regions of the protein as determined by NMR, and in the remaining two cases, the large structural change may be due to force field deficiencies. The overall accuracy of the empirical methods are slightly improved by annealing the CHARMM structure with ProCS15, which may suggest that the minor structural changes introduced by ProCS15-based annealing improves the accuracy of the protein structures. Having established that QM-based chemical shift prediction can deliver the same accuracy as empirical shift predictors we hope this can help increase the accuracy of related approaches such as QM/MM or linear scaling approaches or interpreting protein structural dynamics from QM-derived chemical shift.

Image encryption algorithm based on multiple mixed hash functions and cyclic shift

NASA Astrophysics Data System (ADS)

Wang, Xingyuan; Zhu, Xiaoqiang; Wu, Xiangjun; Zhang, Yingqian

2018-08-01

This paper proposes a new one-time pad scheme for chaotic image encryption that is based on the multiple mixed hash functions and the cyclic-shift function. The initial value is generated using both information of the plaintext image and the chaotic sequences, which are calculated from the SHA1 and MD5 hash algorithms. The scrambling sequences are generated by the nonlinear equations and logistic map. This paper aims to improve the deficiencies of traditional Baptista algorithms and its improved algorithms. We employ the cyclic-shift function and piece-wise linear chaotic maps (PWLCM), which give each shift number the characteristics of chaos, to diffuse the image. Experimental results and security analysis show that the new scheme has better security and can resist common attacks.

[Filtering facepieces: effect of oily aerosol load on penetration through the filtering material].

PubMed

Plebani, Carmela; Listrani, S; Di Luigi, M

2010-01-01

Electrostatic filters are widely used in applications requiring high filtration efficiency and low pressure drop. However various studies showed that the penetration through electrostatic filters increases during exposure to an aerosol flow. This study investigates the effects of prolonged exposure to an oily aerosol on the penetration through filtering facepieces available on the market. Some samples of FFP1, FFP2 and FFP3 filtering facepieces were exposed for 8 hours consecutively to a paraffin oil polydisperse aerosol. At the end of the exposure about 830 mg of paraffin oil were deposited in the facepiece. All the examined facepieces showed penetration values that increased with paraffin oil load while pressure drop values were substantially the same before and after exposure. The measured maximum penetration values did not exceed the maximum penetration values allowed by the European technical standards, except in one case. According to the literature, 830 mg of oil load in a facepiece is not feasible in workplaces over an eight- hour shift. However, the trend of the penetration versus exposure mass suggests that if the load increases, the penetration may exceed the maximum allowed values. For comparison a mechanical filter was also studied. This showed an initial pressure drop higher than FFP2 filtering facepieces characterized by comparable penetration values. During exposure the pressure drop virtually doubled while penetration did not change. The increase in penetration with no increase in pressure drop in the analyzed facepieces indicates that it is necessary to comply with the information supplied by the manufacturer that restricts their use to a single shift.

Covert shift of attention modulates the value encoding in the orbitofrontal cortex

PubMed Central

Xie, Yang; Nie, Chechang

2018-01-01

During value-based decision making, we often evaluate the value of each option sequentially by shifting our attention, even when the options are presented simultaneously. The orbitofrontal cortex (OFC) has been suggested to encode value during value-based decision making. Yet it is not known how its activity is modulated by attention shifts. We investigated this question by employing a passive viewing task that allowed us to disentangle effects of attention, value, choice and eye movement. We found that the attention modulated OFC activity through a winner-take-all mechanism. When we attracted the monkeys’ attention covertly, the OFC neuronal activity reflected the reward value of the newly attended cue. The shift of attention could be explained by a normalization model. Our results strongly argue for the hypothesis that the OFC neuronal activity represents the value of the attended item. They provide important insights toward understanding the OFC’s role in value-based decision making. PMID:29533184

Covert shift of attention modulates the value encoding in the orbitofrontal cortex.

PubMed

Xie, Yang; Nie, Chechang; Yang, Tianming

2018-03-13

During value-based decision making, we often evaluate the value of each option sequentially by shifting our attention, even when the options are presented simultaneously. The orbitofrontal cortex (OFC) has been suggested to encode value during value-based decision making. Yet it is not known how its activity is modulated by attention shifts. We investigated this question by employing a passive viewing task that allowed us to disentangle effects of attention, value, choice and eye movement. We found that the attention modulated OFC activity through a winner-take-all mechanism. When we attracted the monkeys' attention covertly, the OFC neuronal activity reflected the reward value of the newly attended cue. The shift of attention could be explained by a normalization model. Our results strongly argue for the hypothesis that the OFC neuronal activity represents the value of the attended item. They provide important insights toward understanding the OFC's role in value-based decision making. © 2018, Xie et al.

Self-potential response to periodic pumping test: a numerical study

NASA Astrophysics Data System (ADS)

Konosavsky, Pavel; Maineult, Alexis; Narbut, Mikhail; Titov, Konstantin

2017-09-01

We numerically model self-potential responses associated with periodic pumping test experiments by sequential calculation of the hydraulic response and the coupled electrical potential. We assume the pumping test experiments with a fully saturated confined aquifer. Application of different excitation functions leads to quasi-linear trends in electrical records whose direction and intensity depend on the form of the excitation function. The hydraulic response is phase shifted compared to the excitation function; the phase shift increases quasi-linearly with the distance from the pumping well. For the electrical signals, we investigated separately the cases of conducting and insulating casings of the pumping well. For the conducting casing the electrical signals are larger in magnitude than that for the insulating casing; they reproduce the drawdown signals in the pumping well at any distance from the well and exhibit any phase shift with the increased distance. For the insulating casing, the electrical signals are phase shifted and their shape depends on the distance from the pumping well. Three characteristic regimes were found for the phase shift, φ, with the increased distance and for various hydraulic diffusivity values. At small distances φ increases quasi-linearly; at intermediate distances φ attends the value of π/2 and stay about this value (for relatively small diffusivity values); and at large distances φ attends the value of π and, stay about this value at larger distances. This behaviour of the electrical signals can be explained by two electrical sources of reverse polarity. They are (i) linear, time independent, and located at the pumping interval of the well; and (ii) volumetric, time dependent, with maximum value located in the aquifer at the distance corresponding to maximum variation of the hydraulic head magnitude with time. We also model the variation of the amplitude and phase of the hydraulic and electrical signals with increased excitation function period, and we show the characteristic periods corresponding to transition of the periodic pumping test regime to the classical pumping test regime, when the excitation function is considered as the step-function. This transition depends on the distance from the pumping well and the hydraulic diffusivity value of aquifer. Finally, with this modelling of saturated flow we reproduced in sufficient details the field data previously obtained by Maineult et al.

A diesel fuel processor for fuel-cell-based auxiliary power unit applications

NASA Astrophysics Data System (ADS)

Samsun, Remzi Can; Krekel, Daniel; Pasel, Joachim; Prawitz, Matthias; Peters, Ralf; Stolten, Detlef

2017-07-01

Producing a hydrogen-rich gas from diesel fuel enables the efficient generation of electricity in a fuel-cell-based auxiliary power unit. In recent years, significant progress has been achieved in diesel reforming. One issue encountered is the stable operation of water-gas shift reactors with real reformates. A new fuel processor is developed using a commercial shift catalyst. The system is operated using optimized start-up and shut-down strategies. Experiments with diesel and kerosene fuels show slight performance drops in the shift reactor during continuous operation for 100 h. CO concentrations much lower than the target value are achieved during system operation in auxiliary power unit mode at partial loads of up to 60%. The regeneration leads to full recovery of the shift activity. Finally, a new operation strategy is developed whereby the gas hourly space velocity of the shift stages is re-designed. This strategy is validated using different diesel and kerosene fuels, showing a maximum CO concentration of 1.5% at the fuel processor outlet under extreme conditions, which can be tolerated by a high-temperature PEFC. The proposed operation strategy solves the issue of strong performance drop in the shift reactor and makes this technology available for reducing emissions in the transportation sector.

Prethermalization and persistent order in the absence of a thermal phase transition

NASA Astrophysics Data System (ADS)

Halimeh, Jad C.; Zauner-Stauber, Valentin; McCulloch, Ian P.; de Vega, Inés; Schollwöck, Ulrich; Kastner, Michael

2017-01-01

We numerically study the dynamics after a parameter quench in the one-dimensional transverse-field Ising model with long-range interactions (∝1 /rα with distance r ), for finite chains and also directly in the thermodynamic limit. In nonequilibrium, i.e., before the system settles into a thermal state, we find a long-lived regime that is characterized by a prethermal value of the magnetization, which in general differs from its thermal value. We find that the ferromagnetic phase is stabilized dynamically: as a function of the quench parameter, the prethermal magnetization shows a transition between a symmetry-broken and a symmetric phase, even for those values of α for which no finite-temperature transition occurs in equilibrium. The dynamical critical point is shifted with respect to the equilibrium one, and the shift is found to depend on α as well as on the quench parameters.

Phase-shift detection in a Fourier-transform method for temperature sensing using a tapered fiber microknot resonator.

PubMed

Larocque, Hugo; Lu, Ping; Bao, Xiaoyi

2016-04-01

Phase-shift detection in a fast-Fourier-transform (FFT)-based spectrum analysis technique for temperature sensing using a tapered fiber microknot resonator is proposed and demonstrated. Multiple transmission peaks in the FFT spectrum of the device were identified as optical modes having completed different amounts of round trips within the ring structure. Temperature variation induced phase shifts for each set of peaks were characterized, and experimental results show that different peaks have distinct temperature sensitivities reaching values up to -0.542  rad/°C, which is about 10 times greater than that of a regular adiabatic taper Mach-Zehnder interferometer when using similar phase-tracking schemes.

Selection for Protein Kinetic Stability Connects Denaturation Temperatures to Organismal Temperatures and Provides Clues to Archaean Life

PubMed Central

Romero-Romero, M. Luisa; Risso, Valeria A.; Martinez-Rodriguez, Sergio; Gaucher, Eric A.; Ibarra-Molero, Beatriz; Sanchez-Ruiz, Jose M.

2016-01-01

The relationship between the denaturation temperatures of proteins (Tm values) and the living temperatures of their host organisms (environmental temperatures: TENV values) is poorly understood. Since different proteins in the same organism may show widely different Tm’s, no simple universal relationship between Tm and TENV should hold, other than Tm≥TENV. Yet, when analyzing a set of homologous proteins from different hosts, Tm’s are oftentimes found to correlate with TENV’s but this correlation is shifted upward on the Tm axis. Supporting this trend, we recently reported Tm’s for resurrected Precambrian thioredoxins that mirror a proposed environmental cooling over long geological time, while remaining a shocking ~50°C above the proposed ancestral ocean temperatures. Here, we show that natural selection for protein kinetic stability (denaturation rate) can produce a Tm↔TENV correlation with a large upward shift in Tm. A model for protein stability evolution suggests a link between the Tm shift and the in vivo lifetime of a protein and, more specifically, allows us to estimate ancestral environmental temperatures from experimental denaturation rates for resurrected Precambrian thioredoxins. The TENV values thus obtained match the proposed ancestral ocean cooling, support comparatively high Archaean temperatures, and are consistent with a recent proposal for the environmental temperature (above 75°C) that hosted the last universal common ancestor. More generally, this work provides a framework for understanding how features of protein stability reflect the environmental temperatures of the host organisms. PMID:27253436

Spatiotemporal variability of extreme temperature frequency and amplitude in China

NASA Astrophysics Data System (ADS)

Zhang, Yuanjie; Gao, Zhiqiu; Pan, Zaitao; Li, Dan; Huang, Xinhui

2017-03-01

Temperature extremes in China are examined based on daily maximum and minimum temperatures from station observations and multiple global climate models. The magnitude and frequency of extremes are expressed in terms of return values and periods, respectively, estimated by the fitted Generalized Extreme Value (GEV) distribution of annual extreme temperatures. The observations suggest that changes in temperature extremes considerably exceed changes in the respective climatological means during the past five decades, with greater amplitude of increases in cold extremes than in warm extremes. The frequency of warm (cold) extremes increases (decreases) over most areas, with an increasingly faster rate as the extremity level rises. Changes in warm extremes are more dependent on the varying shape of GEV distribution than the location shift, whereas changes in cold extremes are more closely associated with the location shift. The models simulate the overall pattern of temperature extremes during 1961-1981 reasonably well in China, but they show a smaller asymmetry between changes in warm and cold extremes primarily due to their underestimation of increases in cold extremes especially over southern China. Projections from a high emission scenario show the multi-model median change in warm and cold extremes by 2040 relative to 1971 will be 2.6 °C and 2.8 °C, respectively, with the strongest changes in cold extremes shifting southward. By 2040, warm extremes at the 1971 20-year return values would occur about every three years, while the 1971 cold extremes would occur once in > 500 years.

Crystal structures, spectroscopic and theoretical study of novel Schiff bases of 2-(methylthiomethyl)anilines.

PubMed

Olalekan, Temitope E; Adejoro, Isaiah A; VanBrecht, Bernardus; Watkins, Gareth M

2015-03-15

New Schiff bases derived from p-methoxysalicylaldehyde and 2-(methylthiomethyl)anilines (substituted with methyl, methoxy, nitro) were synthesized and characterized by elemental analyses, FT-IR, NMR, electronic spectra and quantum chemical calculations. X-ray crystallography of two compounds showed the solid structures are stabilized by intramolecular and intermolecular H-bonds. The effect of OH⋯N interaction between the phenolic hydrogen and imine nitrogen on the proton and carbon NMR shifts, and the role of CH⋯O and CH⋯S contacts are discussed. The bond lengths and angles, (1)H and (13)C NMR data, E(LUMO-HOMO), dipole moments and polarizability of the compounds were predicted by density functional theory, DFT (B3LYP/6-31G∗∗) method. The experimental geometric parameters and the NMR shifts were compared with the calculated values, which gave good correlations. The electronic effects of aryl ring substituents (methyl, methoxy and nitro) on the properties of the resulting compounds, such as the color, NMR shifts, electronic spectra and the calculated energy band gaps, dipole moments and polarizability are discussed. Increase in electron density shifted the phenolic proton resonance to lower fields. The methoxy-substituted compound has a small dipole moment and subsequent large polarizability value. Highest polarity was indicated by the nitro compound which also showed high polarizability due to its larger size. The energy gaps obtained from E(LUMO-HOMO) calculations suggest these compounds may have applications as organic semiconducting materials. Copyright © 2014 Elsevier B.V. All rights reserved.

An assessment of occupational exposure to polycyclic aromatic hydrocarbons in the UK.

PubMed

Unwin, John; Cocker, John; Scobbie, Emma; Chambers, Helen

2006-06-01

A cross-industry occupational hygiene survey was commissioned by the Health and Safety Executive (HSE) to determine the levels of polycyclic aromatic hydrocarbon (PAH) exposure in UK industry and to determine if one or more target analytes were suitable as markers for assessing total exposure to PAHs. There were no broadly applicable UK exposure standards for assessing total exposure to PAHs. Until 1993 a guidance value for assessing exposure in coke ovens only, where PAH exposure is known to be the highest, was based on gravimetric analysis of cyclohexane-soluble material. Biological monitoring based on urinary 1-hydroxypyrene (1-OHP) is widely reported to be an effective indicator of exposure by both dermal and inhalation routes but there was no UK guidance value. The survey involved an occupational hygiene study of 25 sites using both airborne monitoring of a total of 17 individual PAHs and biological monitoring. The results showed 8 h TWA levels of total PAH in air ranged from 0.4 to 1912.6 microg m(-3) with a GM of 15.8 microg m(-3). The profile of PAHs was dominated by naphthalene, the most volatile 2-ring PAH. Airborne benzo(a)pyrene (BaP) correlated well (r(2) = 0.971) with levels of carcinogenic 4-6 ring PAHs and was an effective marker of exposure for all industries where significant particle bound PAH levels were found and, in particular, for CTPV exposure. The 8 h TWA levels of BaP ranged from <0.01 to 6.21 microg m(-3) with a GM of 0.036 microg m(-3); 90% were <0.75 microg m(-3) and 95% were <2.0 microg m(-3). Two hundred and eighteen urine samples collected from different workers at the end of shift and 213 samples collected pre-shift next day were analysed for 1-OHP. Levels of 1-OHP in end-of-shift samples were generally higher than those in pre-shift-next-day samples and showed a good correlation (r(2) = 0.768) to airborne BaP levels if samples from workers using respiratory protection or with significant dermal exposure were excluded. Urinary 1-OHP in end-of-shift samples ranged from the limit of detection (0.5 micromol mol(-1) creatinine) to 60 micromol mol(-1) creatinine with a mean of 2.49 micromol mol(-1) and a 90th percentile value of 6.7 micromol mol(-1) creatinine. The highest 1-OHP levels were found in samples from workers impregnating timber with creosote where exposure was dominated by naphthalene. If the 11 samples from these workers were excluded from the dataset, the 90% value for end-of-shift urine samples was 4 micromol mol(-1) creatinine (n = 207) and this value has since been adopted by the HSE as a biological monitoring benchmark value.

Effects of fatigue on immune function in nurses performing shift work.

PubMed

Nagai, Makie; Morikawa, Yuko; Kitaoka, Kazuyo; Nakamura, Koshi; Sakurai, Masaru; Nishijo, Muneko; Hamazaki, Yuko; Maruzeni, Shoko; Nakagawa, Hideaki

2011-01-01

We investigated the effects of fatigue on NK cell function and lymphocyte subpopulations in nurses performing shift work using a longitudinal design. Fifty-seven female nurses engaged in shift work at a hospital in Japan were selected for our study cohort. The hospital used a counterclockwise rotating three-shift system. Night shifts followed day shifts after a seven-hour interval. Immune parameters measured at the beginning of the day shift through to the end of the night shift were compared between two groups stratified by their level of fatigue. Statistical differences were evaluated after adjusting for baseline immune values and other demographic features. Subjective feelings of fatigue increased progressively from the beginning of day shifts to the end of night shifts. From the beginning of day shifts to the end of night shifts, NK cell activity and CD16(+)CD56(+) lymphocytes decreased, while CD3(+) and CD4(+) lymphocytes increased. The group with the greater increase in fatigue showed a larger decrease in NK cell activity and a larger increase in CD4(+)lymphocytes when compared with the group reporting less fatigue. These findings did not change after adjusting for demographic factors and sleep hours. Our data suggest that shift work has deleterious effects on NK cell function and that the effects depend on the degree of fatigue. Proper management of shift work may lessen fatigue in workers and also ameliorate many health problems experienced by shift workers.

Elbow Room for Best Practice? Montgomery, Patients' values, and Balanced Decision-Making in Person-Centred Clinical Care.

PubMed

Herring, Jonathan; Fulford, Kmw; Dunn, Michael; Handa, Ashoki

2017-11-01

The UK Supreme Court Montgomery judgment marks a decisive shift in the legal test of duty of care in the context of consent to treatment, from the perspective of the clinician (as represented by Bolam rules) to that of the patient. A majority of commentators on Montgomery have focused on the implications of the judgment for disclosure of risk. In this article, we set risk disclosure in context with three further elements of the judgment: benefits, options, and dialogue. These elements, we argue, taken together with risk disclosure, reflect the origins of the Montgomery ruling in a model of consent based on autonomy of patient choice through shared decision-making with their doctor. This model reflects recent developments in both law and medicine and is widely regarded (by the General Medical Council and others) as representing best practice in contemporary person-centred medicine. So understood, we suggest, the shift marked by Montgomery in the basis of duty of care is a shift in underpinning values: it is a shift from the clinician's interpretation about what would be best for patients to the values of (to what is significant or matters from the perspective of) the particular patient concerned in the decision in question. But the values of the particular patient do not thereby become paramount. The Montgomery test of duty of care requires the values of the particular patient to be balanced alongside the values of a reasonable person in the patient's position. We illustrate some of the practical challenges arising from the balance of considerations required by Montgomery with examples from surgical care. These examples show the extent to which Montgomery, in mirroring the realities of clinical decision-making, provides elbowroom for best practice in person-centred clinical care. © The Author 2017. Published by Oxford University Press; all rights reserved. For Permissions, please email: journals.permissions@oup.com.

Pauling Electronegativity On/Off Effects Assessed by 13 C and 29 Si NMR Spectroscopic Analysis.

PubMed

Benedetti, Michele; De Castro, Federica; Fanizzi, Francesco P

2017-11-27

In carbon and silicon tetrahalide compounds, the experimental 13 C and 29 Si NMR chemical-shift values are known to increase or decrease on increasing the overall sum of the ionic radii of the bonded halides Σ(r h ) (normal and inverse halogen dependence (NHD and IHD, respectively)). Herein, we extrapolate the main factors responsible for such NMR chemical shifts. Intriguingly, we found a characteristic value for the overall sum of the Pauling electronegativities of the bonded halides Σ(χ h ), which works as a triggering factor to determine the transition from the NHD to IHD. Below this Σ(χ h ) value, the chemical shift of the central atom was strictly related to only the Σ(r h ) value, thus producing a NHD trend. Conversely, above this value, the chemical shift of the central atom was dependent on both the Σ(r h ) and Σ(χ h ) values, thus producing a IHD trend. A simple model, in which the effect of the Σ(χ h ) value on 13 C and 29 Si NMR chemical shifts is related to an apparent increase in the Σ(r h ) value, is deduced. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Reconstructing Past Vegetation Types During the Late Holocene Using Stable Carbon Isotopes of Leporids from Archaeological Sites in the American Southwest

NASA Astrophysics Data System (ADS)

Mauldin, R. P.; Munoz, C.; Kemp, L.; Hard, R.

2012-12-01

Stable carbon isotopes (δ13C) from bone collagen in leporids provide high-resolution vegetation reconstruction. Leporids [e.g., cottontails (Sylvilagus sp.), jackrabbits (Lepus sp.)] die young (ca. 2 years) and use small home ranges (< 1 km2). They consume a variety of vegetation, including plants that use both C3 and C4/CAM photosynthetic pathways. Leporids appear to focus on new growth as it becomes available throughout the year, perhaps as a function of water content. Their diet, and their bone collagen, provides a high-resolution view of the carbon isotopic values present in their local plant community. Here we provide an example of the use of leporid bone collagen for reconstruction of past vegetation types using data from several archaeological sites as well as modern collections. All samples are from a basin and range setting within the Chihuahuan Desert in far west Texas and southern New Mexico, USA. The sites span a period back to roughly 1350 BP. Isotopic patterns in leporid collagen show clear evidence of change in vegetation from around 775 BP to the modern period, with a dramatic shift of 4.2‰ in median δ13C values over this period in jackrabbit collagen and a 7.3‰ decrease in median carbon isotopic values in cottontail rabbits. These data suggest a significant increase in C3 plants in leporid diet, and by extension a relative increase in these plant types in the local environment sampled by leporids. This shift is consistent with historic accounts of more C3 mesquite, possibly because of historic land use and ranching practices in the 1800s. However, while this shift may have been accelerated by historic land use changes, our data suggest that the vegetation shift began several hundred years earlier during the prehistoric period. The prehistoric collagen isotopic record also shows increased sample variability through time in both species, suggesting that year-to-year variability in vegetation may have increased late in that sequence. Our results, then, clearly show the potential of leporids for high resolution tracking of vegetation shifts. As leporids are common in paleontological and archaeological sites throughout the temperate zones, their use as a vegetation and climate proxy has wide application.

Protein structure refinement using a quantum mechanics-based chemical shielding predictor† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c6sc04344e Click here for additional data file.

PubMed Central

2017-01-01

The accurate prediction of protein chemical shifts using a quantum mechanics (QM)-based method has been the subject of intense research for more than 20 years but so far empirical methods for chemical shift prediction have proven more accurate. In this paper we show that a QM-based predictor of a protein backbone and CB chemical shifts (ProCS15, PeerJ, 2016, 3, e1344) is of comparable accuracy to empirical chemical shift predictors after chemical shift-based structural refinement that removes small structural errors. We present a method by which quantum chemistry based predictions of isotropic chemical shielding values (ProCS15) can be used to refine protein structures using Markov Chain Monte Carlo (MCMC) simulations, relating the chemical shielding values to the experimental chemical shifts probabilistically. Two kinds of MCMC structural refinement simulations were performed using force field geometry optimized X-ray structures as starting points: simulated annealing of the starting structure and constant temperature MCMC simulation followed by simulated annealing of a representative ensemble structure. Annealing of the CHARMM structure changes the CA-RMSD by an average of 0.4 Å but lowers the chemical shift RMSD by 1.0 and 0.7 ppm for CA and N. Conformational averaging has a relatively small effect (0.1–0.2 ppm) on the overall agreement with carbon chemical shifts but lowers the error for nitrogen chemical shifts by 0.4 ppm. If an amino acid specific offset is included the ProCS15 predicted chemical shifts have RMSD values relative to experiments that are comparable to popular empirical chemical shift predictors. The annealed representative ensemble structures differ in CA-RMSD relative to the initial structures by an average of 2.0 Å, with >2.0 Å difference for six proteins. In four of the cases, the largest structural differences arise in structurally flexible regions of the protein as determined by NMR, and in the remaining two cases, the large structural change may be due to force field deficiencies. The overall accuracy of the empirical methods are slightly improved by annealing the CHARMM structure with ProCS15, which may suggest that the minor structural changes introduced by ProCS15-based annealing improves the accuracy of the protein structures. Having established that QM-based chemical shift prediction can deliver the same accuracy as empirical shift predictors we hope this can help increase the accuracy of related approaches such as QM/MM or linear scaling approaches or interpreting protein structural dynamics from QM-derived chemical shift. PMID:28451325

Effect of Plastic Hot Deformation on the Hardness and Continuous Cooling Transformations of 22MnB5 Microalloyed Boron Steel

NASA Astrophysics Data System (ADS)

Barcellona, A.; Palmeri, D.

2009-05-01

The strains, transformation temperatures, microstructure, and microhardness of a microalloyed boron and aluminum precoated steel, which has been isothermally deformed under uniaxial tensile tests, have been investigated at temperatures between 873 and 1223 K, using a fixed strain rate value of 0.08 s-1. The effect of each factor, such as temperature and strain value, has been later valued considering the shift generated on the continuous cooling transformation (CCT) diagram. The experimental results consist of the starting temperatures that occur for each transformation, the microhardness values, and the obtained microstructure at the end of each thermomechanical treatment. All the thermomechanical treatments were performed using the thermomechanical simulator Gleeble 1500. The results showed that increasing hot prestrain (HPS) values generate, at the same cooling rate, lower hardness values; this means that the increasing of HPS generates a shift of the CCT diagram toward a lower starting time for each transformation. Therefore, high values of hot deformations during the hot stamping process require a strict control of the cooling process in order to ensure cooling rate values that allow maintaining good mechanical component characteristics. This phenomenon is amplified when the prestrain occurs at lower temperatures, and thus, it is very sensitive to the temperature level.

HeLa cells response to photodynamic treatment with Radachlorin at various irradiation parameters

NASA Astrophysics Data System (ADS)

Belashov, A. V.; Zhikhoreva, A. A.; Belyaeva, T. N.; Kornilova, E. S.; Petrov, N. V.; Salova, A. V.; Semenova, I. V.; Vasyutinskii, O. S.

2017-07-01

Measurements of average phase shifts introduced by living HeLa cells to probe wave front were carried out. Variations of this value were monitored in the course of morphological changes caused by photodynamic treatment at various irradiation doses. Observations of changes in living cells were also performed by means of far field optical microscopy and confocal fluorescent microscopy. Quantitative analysis of the data obtained shows that average phase shift introduced by the cells may either increase or decrease depending upon major parameters of the treatment.

Determination of Young's modulus of epoxy coated polyethylene micro-cantilever using phase-shift shadow moiré method

NASA Astrophysics Data System (ADS)

Lim, J. H.; Ratnam, M. M.; Azid, I. A.; Mutharasu, D.

2011-11-01

Young's moduli of various epoxy coated polyethylene terephthalate (PET) micro-cantilevers were determined from the deflection results obtained using the phase-shift shadow moiré (PSSM) method. The filler materials for epoxy coatings were aluminum and graphite powders that were mixed with epoxy at various percentages. Young's moduli were calculated from theory based on the deflection results. The PET micro-cantilever coated with aluminum-epoxy coating showed increasing value of Young's modulus when the ratios of the aluminum-epoxy were increased. The graphite-epoxy coating on the PET micro-cantilever also showed the same trend. The experimental results also show that Young's modulus of the graphite-epoxy coating is higher than aluminum-epoxy coating in comparison at the same mixing ratio.

Photovoltaic dependence of photorefractive grating on the externally applied dc electric field

NASA Astrophysics Data System (ADS)

Maurya, M. K.; Yadav, R. A.

2013-04-01

Photovoltaic dependence of photorefractive grating (i.e., space-charge field and phase-shift of the index grating) on the externally applied dc electric field in photovoltaic-photorefractive materials has been investigated. The influence of photovoltaic field (EPhN), diffusion field and carrier concentration ratio r (donor/acceptor impurity concentration ratio) on the space-charge field (SCF) and phase-shift of the index grating in the presence and absence of the externally applied dc electric field have also been studied in details. Our results show that, for a given value of EPhN and r, the magnitude of the SCF and phase-shift of the index grating can be enhanced significantly by employing the lower dc electric field (EON<10) across the photovoltaic-photorefractive crystal and higher value of diffusion field (EDN>40). Such an enhancement in the magnitude of the SCF and phase-shift of the index grating are responsible for the strongest beam coupling in photovoltaic-photorefractive materials. This sufficiently strong beam coupling increases the two-beam coupling gain that may be exceed the absorption and reflection losses of the photovoltaic-photorefractive sample, and optical amplification can occur. The higher value of optical amplification in photovoltaic-photorefractive sample is required for the every applications of photorefractive effect so that technology based on the photorefractive effect such as holographic storage devices, optical information processing, acousto-optic tunable filters, gyro-sensors, optical modulators, optical switches, photorefractive-photovoltaic solitons, biomedical applications, and frequency converters could be improved.

123s and ABCs: developmental shifts in logarithmic-to-linear responding reflect fluency with sequence values.

PubMed

Hurst, Michelle; Monahan, K Leigh; Heller, Elizabeth; Cordes, Sara

2014-11-01

When placing numbers along a number line with endpoints 0 and 1000, children generally space numbers logarithmically until around the age of 7, when they shift to a predominantly linear pattern of responding. This developmental shift of responding on the number placement task has been argued to be indicative of a shift in the format of the underlying representation of number (Siegler & Opfer, ). In the current study, we provide evidence from both child and adult participants to suggest that performance on the number placement task may not reflect the structure of the mental number line, but instead is a function of the fluency (i.e. ease) with which the individual can work with the values in the sequence. In Experiment 1, adult participants respond logarithmically when placing numbers on a line with less familiar anchors (1639 to 2897), despite linear responding on control tasks with standard anchors involving a similar range (0 to 1287) and a similar numerical magnitude (2000 to 3000). In Experiment 2, we show a similar developmental shift in childhood from logarithmic to linear responding for a non-numerical sequence with no inherent magnitude (the alphabet). In conclusion, we argue that the developmental trend towards linear behavior on the number line task is a product of successful strategy use and mental fluency with the values of the sequence, resulting from familiarity with endpoints and increased knowledge about general ordering principles of the sequence.A video abstract of this article can be viewed at:http://www.youtube.com/watch?v=zg5Q2LIFk3M. © 2014 John Wiley & Sons Ltd.

Functional Similarity of Medial Superior Parietal Areas for Shift-Selective Attention Signals in Humans and Monkeys.

PubMed

Caspari, Natalie; Arsenault, John T; Vandenberghe, Rik; Vanduffel, Wim

2018-06-01

We continually shift our attention between items in the visual environment. These attention shifts are usually based on task relevance (top-down) or the saliency of a sudden, unexpected stimulus (bottom-up), and are typically followed by goal-directed actions. It could be argued that any species that can covertly shift its focus of attention will rely on similar, evolutionarily conserved neural substrates for processing such shift-signals. To address this possibility, we performed comparative fMRI experiments in humans and monkeys, combining traditional, and novel, data-driven analytical approaches. Specifically, we examined correspondences between monkey and human brain areas activated during covert attention shifts. When "shift" events were compared with "stay" events, the medial (superior) parietal lobe (mSPL) and inferior parietal lobes showed similar shift sensitivities across species, whereas frontal activations were stronger in monkeys. To identify, in a data-driven manner, monkey regions that corresponded with human shift-selective SPL, we used a novel interspecies beta-correlation strategy whereby task-related beta-values were correlated across voxels or regions-of-interest in the 2 species. Monkey medial parietal areas V6/V6A most consistently correlated with shift-selective human mSPL. Our results indicate that both species recruit corresponding, evolutionarily conserved regions within the medial superior parietal lobe for shifting spatial attention.

Implications of human value shift and persistence for biodiversity conservation.

PubMed

Manfredo, Michael J; Teel, Tara L; Dietsch, Alia M

2016-04-01

Large-scale change in human values and associated behavior change is believed by some to be the ultimate solution to achieve global biodiversity conservation. Yet little is known about the dynamics of values. We contribute to this area of inquiry by examining the trajectory of values affecting views of wildlife in North America. Using data from a 19-state study in the United States and global data from the Schwartz Value Survey, we explored questions of value persistence and change and the nature of attitudinal responses regarding wildlife conservation issues. We found support, based on subjects' ancestry, for the supposition that domination is a prevalent American value orientation toward wildlife that has origins in European Judeo-Christian traditions. Independent of that effect, we also found indications of change. Modernization is contributing to a shift from domination to mutualism value orientations, which is fostering attitudes less centered on human interests and seemingly more consistent with a biocentric philosophy. Our findings suggest that if value shift could be achieved in a purposeful way, then significant and widespread behavior change believed necessary for long-term conservation success may indeed be possible. In particular, greater emphasis on mutualism values may help provide the context for more collaborative approaches to support future conservation efforts. However, given the societal forces at play, it is not at all clear that human-engineered value shift is tenable. Instead of developing strategies aimed at altering values, it may be more productive to create strategies that recognize and work within the boundaries of existing values. Whereas values appear to be in a period of flux, it will be difficult to predict future trends without a better understanding of value formation and shift, particularly under conditions of rapid social-ecological change. © 2016 Society for Conservation Biology.

Metathesis Activity Encoded in the Metallacyclobutane Carbon-13 NMR Chemical Shift Tensors

PubMed Central

2017-01-01

Metallacyclobutanes are an important class of organometallic intermediates, due to their role in olefin metathesis. They can have either planar or puckered rings associated with characteristic chemical and physical properties. Metathesis active metallacyclobutanes have short M–Cα/α′ and M···Cβ distances, long Cα/α′–Cβ bond length, and isotropic 13C chemical shifts for both early d0 and late d4 transition metal compounds for the α- and β-carbons appearing at ca. 100 and 0 ppm, respectively. Metallacyclobutanes that do not show metathesis activity have 13C chemical shifts of the α- and β-carbons at typically 40 and 30 ppm, respectively, for d0 systems, with upfield shifts to ca. −30 ppm for the α-carbon of metallacycles with higher dn electron counts (n = 2 and 6). Measurements of the chemical shift tensor by solid-state NMR combined with an orbital (natural chemical shift, NCS) analysis of its principal components (δ11 ≥ δ22 ≥ δ33) with two-component calculations show that the specific chemical shift of metathesis active metallacyclobutanes originates from a low-lying empty orbital lying in the plane of the metallacyclobutane with local π*(M–Cα/α′) character. Thus, in the metathesis active metallacyclobutanes, the α-carbons retain some residual alkylidene character, while their β-carbon is shielded, especially in the direction perpendicular to the ring. Overall, the chemical shift tensors directly provide information on the predictive value about the ability of metallacyclobutanes to be olefin metathesis intermediates. PMID:28776018

Shifting and Expanding Forest Values: The Case of the U.S. National Forests

Treesearch

David N. Bengston; Zhi Xu

1996-01-01

The idea that public forest values have changed significantly in recent decades has become widespread. According to this view, forest values-conceptions of what is good or desirable about forests-have changed in two important ways. First, it is often claimed that forest values have shifted, i.e., the relative importance of different values has changed. Social...

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

Balderson, Michael, E-mail: michael.balderson@rmp.uhn.ca; Brown, Derek; Johnson, Patricia

The purpose of this work was to compare static gantry intensity-modulated radiation therapy (IMRT) with volume-modulated arc therapy (VMAT) in terms of tumor control probability (TCP) under scenarios involving large geometric misses, i.e., those beyond what are accounted for when margin expansion is determined. Using a planning approach typical for these treatments, a linear-quadratic–based model for TCP was used to compare mean TCP values for a population of patients who experiences a geometric miss (i.e., systematic and random shifts of the clinical target volume within the planning target dose distribution). A Monte Carlo approach was used to account for themore » different biological sensitivities of a population of patients. Interestingly, for errors consisting of coplanar systematic target volume offsets and three-dimensional random offsets, static gantry IMRT appears to offer an advantage over VMAT in that larger shift errors are tolerated for the same mean TCP. For example, under the conditions simulated, erroneous systematic shifts of 15 mm directly between or directly into static gantry IMRT fields result in mean TCP values between 96% and 98%, whereas the same errors on VMAT plans result in mean TCP values between 45% and 74%. Random geometric shifts of the target volume were characterized using normal distributions in each Cartesian dimension. When the standard deviations were doubled from those values assumed in the derivation of the treatment margins, our model showed a 7% drop in mean TCP for the static gantry IMRT plans but a 20% drop in TCP for the VMAT plans. Although adding a margin for error to a clinical target volume is perhaps the best approach to account for expected geometric misses, this work suggests that static gantry IMRT may offer a treatment that is more tolerant to geometric miss errors than VMAT.« less

Prediction of plant vulnerability to salinity increase in a coastal ecosystem by stable isotopic composition (δ18O) of plant stem water: a model study

USGS Publications Warehouse

Zhai, Lu; Jiang, Jiang; DeAngelis, Donald L.; Sternberg, Leonel d.S.L

2016-01-01

Sea level rise and the subsequent intrusion of saline seawater can result in an increase in soil salinity, and potentially cause coastal salinity-intolerant vegetation (for example, hardwood hammocks or pines) to be replaced by salinity-tolerant vegetation (for example, mangroves or salt marshes). Although the vegetation shifts can be easily monitored by satellite imagery, it is hard to predict a particular area or even a particular tree that is vulnerable to such a shift. To find an appropriate indicator for the potential vegetation shift, we incorporated stable isotope 18O abundance as a tracer in various hydrologic components (for example, vadose zone, water table) in a previously published model describing ecosystem shifts between hammock and mangrove communities in southern Florida. Our simulations showed that (1) there was a linear relationship between salinity and the δ18O value in the water table, whereas this relationship was curvilinear in the vadose zone; (2) hammock trees with higher probability of being replaced by mangroves had higher δ18O values of plant stem water, and this difference could be detected 2 years before the trees reached a tipping point, beyond which future replacement became certain; and (3) individuals that were eventually replaced by mangroves from the hammock tree population with a 50% replacement probability had higher stem water δ18O values 3 years before their replacement became certain compared to those from the same population which were not replaced. Overall, these simulation results suggest that it is promising to track the yearly δ18O values of plant stem water in hammock forests to predict impending salinity stress and mortality.

The remote sensing image segmentation mean shift algorithm parallel processing based on MapReduce

NASA Astrophysics Data System (ADS)

Chen, Xi; Zhou, Liqing

2015-12-01

With the development of satellite remote sensing technology and the remote sensing image data, traditional remote sensing image segmentation technology cannot meet the massive remote sensing image processing and storage requirements. This article put cloud computing and parallel computing technology in remote sensing image segmentation process, and build a cheap and efficient computer cluster system that uses parallel processing to achieve MeanShift algorithm of remote sensing image segmentation based on the MapReduce model, not only to ensure the quality of remote sensing image segmentation, improved split speed, and better meet the real-time requirements. The remote sensing image segmentation MeanShift algorithm parallel processing algorithm based on MapReduce shows certain significance and a realization of value.

Conformal Weyl Gravity and Perihelion Precession

NASA Technical Reports Server (NTRS)

Sultana, Joseph; Kazanas, Demosthenes; Said, Jakson, Levi

2012-01-01

We investigate the perihelion shift of planetary motion in conformal Weyl gravity using the metric of the static, spherically symmetric solution discovered by Mannheim and Kazanas. To this end we employ a procedure similar to that used by Weinberg for the Schwarzschild solution, which has also been used recently to study the solar system effects of the cosmological constant Lambda. We show that besides the general relativistic terms obtained earlier from the Schwarzschild-de Sitter solution, the expression for the perihelion shift includes a negative contribution which arises from the linear term gamma ray in the metric. Using data for perihelion shift observations, we obtain constraints on the value of the constant gammma similar to that obtained earlier using galactic rotational curves.

Ventilatory function in rubber processing workers: acute changes over the workshift.

PubMed Central

Governa, M; Comai, M; Valentino, M; Antonicelli, L; Rinaldi, F; Pisani, E

1987-01-01

When considering rubber tyre manufacturing from an occupational health viewpoint, three areas may be identified in which exposure to respirable materials are potentially harmful: the processing, curing, and talc areas. A study of the ventilatory function of the entire work force employed in the processing area in a rubber tyre manufacturing plant was undertaken to determine whether an acute reduction in lung function occurs over the course of their working shift (the plant worked a three shift system) and whether a chronic exposure to the occupational airborne contaminants causes permanent changes in lung function. The ventilatory function was measured at the worksite at the beginning and immediately after the end of the workshift. No evidence of chronic obstructive pulmonary disease was found and in most cases no significant decline in FEV1 was observed. Only one of the 79 individuals showed a moderate obstruction, measured by the ratio FEV1/FVC which gave the value of 0.55, with no variation over the shift. For non-smokers, the FVC, FEV1, and FEF25-75% were lower in those exposed for more than five years than in those exposed for five years or less. A similar pattern was also observed in the FVC and FEV1 of the smokers. None of these differences was statistically significant. Within each exposure group the pulmonary function of the smokers was lower than that of the non-smokers, but the only significant difference was found in the values of FEF25-75%. Only one man showed a decline in the FEV1/FVC ratio over the shift, but during each shift, a decrease in all the lung function tests was observed. The decrease was smallest during the first of the three shifts. These results are thought to support the hypothesis that there are acute adverse effects over an eight hour shift. Further investigations are needed to discover whether these acute changes in lung function result from a chemical stimulation or irritant receptors in the airways. PMID:3814549

Optical character recognition with feature extraction and associative memory matrix

NASA Astrophysics Data System (ADS)

Sasaki, Osami; Shibahara, Akihito; Suzuki, Takamasa

1998-06-01

A method is proposed in which handwritten characters are recognized using feature extraction and an associative memory matrix. In feature extraction, simple processes such as shifting and superimposing patterns are executed. A memory matrix is generated with singular value decomposition and by modifying small singular values. The method is optically implemented with two liquid crystal displays. Experimental results for the recognition of 25 handwritten alphabet characters clearly shows the effectiveness of the method.

Declining functional connectivity and changing hub locations in Alzheimer's disease: an EEG study.

PubMed

Engels, Marjolein M A; Stam, Cornelis J; van der Flier, Wiesje M; Scheltens, Philip; de Waal, Hanneke; van Straaten, Elisabeth C W

2015-08-20

EEG studies have shown that patients with Alzheimer's disease (AD) have weaker functional connectivity than controls, especially in higher frequency bands. Furthermore, active regions seem more prone to AD pathology. How functional connectivity is affected in AD subgroups of disease severity and how network hubs (highly connected brain areas) change is not known. We compared AD patients with different disease severity and controls in terms of functional connections, hub strength and hub location. We studied routine 21-channel resting-state electroencephalography (EEG) of 318 AD patients (divided into tertiles based on disease severity: mild, moderate and severe AD) and 133 age-matched controls. Functional connectivity between EEG channels was estimated with the Phase Lag Index (PLI). From the PLI-based connectivity matrix, the minimum spanning tree (MST) was derived. For each node (EEG channel) in the MST, the betweenness centrality (BC) was computed, a measure to quantify the relative importance of a node within the network. Then we derived color-coded head plots based on BC values and calculated the center of mass (the exact middle had x and y values of 0). A shifting of the hub locations was defined as a shift of the center of mass on the y-axis across groups. Multivariate general linear models with PLI or BC values as dependent variables and the groups as continuous variables were used in the five conventional frequency bands. We found that functional connectivity decreases with increasing disease severity in the alpha band. All, except for posterior, regions showed increasing BC values with increasing disease severity. The center of mass shifted from posterior to more anterior regions with increasing disease severity in the higher frequency bands, indicating a loss of relative functional importance of the posterior brain regions. In conclusion, we observed decreasing functional connectivity in the posterior regions, together with a shifted hub location from posterior to central regions with increasing AD severity. Relative hub strength decreases in posterior regions while other regions show a relative rise with increasing AD severity, which is in accordance with the activity-dependent degeneration theory. Our results indicate that hubs are disproportionally affected in AD.

Individual differences in the cortisol-awakening response during the first two years of shift work: A longitudinal study in novice police officers.

PubMed

Lammers-van der Holst, Heidi M; Kerkhof, Gerard A

2015-01-01

Cortisol acts as a critical biological intermediary through which chronic stressors like shift work impact upon multiple physiological, neuro-endocrine and hormonal functions. Therefore, the cortisol awakening response (CAR) is suggested as a prime index of shift work tolerance. Repeated assessments of the CAR (calculated as MnInc) in a group of 25 young novice police officers showed that in the interval between about 4 and 14 months after transitioning from regular day work to rotating shift work, mean values began to rise from baseline to significantly higher levels at about 14 months after they commenced shift work. Visual inspection of the individual trends revealed that a subgroup of 10 subjects followed a monotonically rising trend, whereas another 14 subjects, after an initial rise from about 4-14 months, reverted to a smaller, baseline level cortisol response at about 20 months after the start of shift work. If the initial increase in the cortisol response marks the development of a chronic stress response, the subsequent reversal to baseline levels in the subgroup of 14 participants might be indicative of a process of recovery, possibly the development of shift work tolerance.

A method to enhance the measurement accuracy of Raman shift based on high precision calibration technique

NASA Astrophysics Data System (ADS)

Ding, Xiang; Li, Fei; Zhang, Jiyan; Liu, Wenli

2016-10-01

Raman spectrometers are usually calibrated periodically to ensure their measurement accuracy of Raman shift. A combination of a piece of monocrystalline silicon chip and a low pressure discharge lamp is proposed as a candidate for the reference standard of Raman shift. A high precision calibration technique is developed to accurately determine the standard value of the silicon's Raman shift around 520cm-1. The technique is described and illustrated by measuring a piece of silicon chip against three atomic spectral lines of a neon lamp. A commercial Raman spectrometer is employed and its error characteristics of Raman shift are investigated. Error sources are evaluated based on theoretical analysis and experiments, including the sample factor, the instrumental factor, the laser factor and random factors. Experimental results show that the expanded uncertainty of the silicon's Raman shift around 520cm-1 can acheive 0.3 cm-1 (k=2), which is more accurate than most of currently used reference materials. The results are validated by comparison measurement between three Raman spectrometers. It is proved that the technique can remarkably enhance the accuracy of Raman shift, making it possible to use the silicon and the lamp to calibrate Raman spectrometers.

Relativistically corrected nuclear magnetic resonance chemical shifts calculated with the normalized elimination of the small component using an effective potential-NMR chemical shifts of molybdenum and tungsten

NASA Astrophysics Data System (ADS)

Filatov, Michael; Cremer, Dieter

2003-07-01

A new method for relativistically corrected nuclear magnetic resonance (NMR) chemical shifts is developed by combining the individual gauge for the localized orbital approach for density functional theory with the normalized elimination of a small component using an effective potential. The new method is used for the calculation of the NMR chemical shifts of 95Mo and 183W in various molybdenum and tungsten compounds. It is shown that quasirelativistic corrections lead to an average improvement of calculated NMR chemical shift values by 300 and 120 ppm in the case of 95Mo and 183W, respectively, which is mainly due to improvements in the paramagnetic contributions. The relationship between electronic structure of a molecule and the relativistic paramagnetic corrections is discussed. Relativistic effects for the diamagnetic part of the magnetic shielding caused by a relativistic contraction of the s,p orbitals in the core region concern only the shielding values, however, have little consequence for the shift values because of the large independence from electronic structure and a cancellation of these effects in the shift values. It is shown that the relativistic corrections can be improved by level shift operators and a B3LYP hybrid functional, for which Hartree-Fock exchange is reduced to 15%.

The small impact of various partial charge distributions in ground and excited state on the computational Stokes shift of 1-methyl-6-oxyquinolinium betaine in diverse water models

NASA Astrophysics Data System (ADS)

Heid, Esther; Harringer, Sophia; Schröder, Christian

2016-10-01

The influence of the partial charge distribution obtained from quantum mechanics of the solute 1-methyl-6-oxyquinolinium betaine in the ground- and first excited state on the time-dependent Stokes shift is studied via molecular dynamics computer simulation. Furthermore, the effect of the employed solvent model — here the non-polarizable SPC, TIP4P and TIP4P/2005 and the polarizable SWM4 water model — on the solvation dynamics of the system is investigated. The use of different functionals and calculation methods influences the partial charge distribution and the magnitude of the dipole moment of the solute, but not the orientation of the dipole moment. Simulations based on the calculated charge distributions show nearly the same relaxation behavior. Approximating the whole solute molecule by a dipole results in the same relaxation behavior, but lower solvation energies, indicating that the time scale of the Stokes shift does not depend on peculiarities of the solute. However, the SPC and TIP4P water models show too fast dynamics which can be ascribed to a too large diffusion coefficient and too low viscosity. The calculated diffusion coefficient and viscosity for the SWM4 and TIP4P/2005 models coincide well with experimental values and the corresponding relaxation behavior is comparable to experimental values. Furthermore we found that for a quantitative description of the Stokes shift of the applied system at least two solvation shells around the solute have to be taken into account.

Disentangling the f(R)-duality

NASA Astrophysics Data System (ADS)

Broy, Benedict J.; Pedro, Francisco G.; Westphal, Alexander

2015-03-01

Motivated by UV realisations of Starobinsky-like inflation models, we study generic exponential plateau-like potentials to understand whether an exact f(R)-formulation may still be obtained when the asymptotic shift-symmetry of the potential is broken for larger field values. Potentials which break the shift symmetry with rising exponentials at large field values only allow for corresponding f(R)-descriptions with a leading order term Rn with 1

The sensitivity of auditory-motor representations to subtle changes in auditory feedback while singing

PubMed Central

Keough, Dwayne; Jones, Jeffery A.

2009-01-01

Singing requires accurate control of the fundamental frequency (F0) of the voice. This study examined trained singers’ and untrained singers’ (nonsingers’) sensitivity to subtle manipulations in auditory feedback and the subsequent effect on the mapping between F0 feedback and vocal control. Participants produced the consonant-vowel ∕ta∕ while receiving auditory feedback that was shifted up and down in frequency. Results showed that singers and nonsingers compensated to a similar degree when presented with frequency-altered feedback (FAF); however, singers’ F0 values were consistently closer to the intended pitch target. Moreover, singers initiated their compensatory responses when auditory feedback was shifted up or down 6 cents or more, compared to nonsingers who began compensating when feedback was shifted up 26 cents and down 22 cents. Additionally, examination of the first 50 ms of vocalization indicated that participants commenced subsequent vocal utterances, during FAF, near the F0 value on previous shift trials. Interestingly, nonsingers commenced F0 productions below the pitch target and increased their F0 until they matched the note. Thus, singers and nonsingers rely on an internal model to regulate voice F0, but singers’ models appear to be more sensitive in response to subtle discrepancies in auditory feedback. PMID:19640048

The sensitivity of auditory-motor representations to subtle changes in auditory feedback while singing.

PubMed

Keough, Dwayne; Jones, Jeffery A

2009-08-01

Singing requires accurate control of the fundamental frequency (F0) of the voice. This study examined trained singers' and untrained singers' (nonsingers') sensitivity to subtle manipulations in auditory feedback and the subsequent effect on the mapping between F0 feedback and vocal control. Participants produced the consonant-vowel /ta/ while receiving auditory feedback that was shifted up and down in frequency. Results showed that singers and nonsingers compensated to a similar degree when presented with frequency-altered feedback (FAF); however, singers' F0 values were consistently closer to the intended pitch target. Moreover, singers initiated their compensatory responses when auditory feedback was shifted up or down 6 cents or more, compared to nonsingers who began compensating when feedback was shifted up 26 cents and down 22 cents. Additionally, examination of the first 50 ms of vocalization indicated that participants commenced subsequent vocal utterances, during FAF, near the F0 value on previous shift trials. Interestingly, nonsingers commenced F0 productions below the pitch target and increased their F0 until they matched the note. Thus, singers and nonsingers rely on an internal model to regulate voice F0, but singers' models appear to be more sensitive in response to subtle discrepancies in auditory feedback.

Shifting Identity: New Conditions and the Transformation of Practice--Teaching within Post-Compulsory Education.

ERIC Educational Resources Information Center

Avis, James

1999-01-01

Exploration of the social and economic context of further education in England shows increased collegiality and a culture of continuous improvement have transformed teaching and learning. These changes take place within a modernizing strategy focused on value-added education and economic competitiveness. (SK)

Geochemical structure of the Hawaiian plume: Sr, Nd, and Os isotopes in the 2.8 km HSDP-2 section of Mauna Kea volcano

NASA Astrophysics Data System (ADS)

Bryce, Julia G.; Depaolo, Donald J.; Lassiter, John C.

2005-09-01

Sr, Nd, and Os isotopic measurements were made on 110 Mauna Kea lava and hyaloclastite samples from the drillcore retrieved from the second phase of the Hawaii Scientific Drilling Project (HSDP-2). The samples come from depths of 255 to 3098 meters below sea level, span an age range from 200 to about 550-600 kyr, and represent an ordered record of the lava output from Mauna Kea volcano as it drifted a distance of about 40 km over the magma-producing region of the Hawaiian hot spot. The deepest (oldest) samples represent the time when Mauna Kea was closest to the center of the melting region of the Hawaiian plume. The Sr and Os isotopic ratios in HSDP-2 lavas show only subtle isotopic shifts over the ˜400 kyr history represented by the core. Neodymium isotopes (ɛNd values) increase systematically with decreasing age from an average value of nearly +6.5 to an average value of +7.5. This small change corresponds to subtle shifts in 87Sr/86Sr and 187Os/188Os isotope ratios, with small shifts of ɛHf, a large shift in 208Pb/204Pb and 208Pb/207Pb values, and with a very large shift in He isotope ratios from R/RA values of about 7-8 to values as high as 25. When Mauna Kea was closest to the plume core, the magma source did not have primitive characteristics for Nd, Sr, Pb, Hf, and Os isotopes but did have variable amounts of "primitive" helium. The systematic shifts in Nd, Hf, Pb, and He isotopes are consistent with radial isotopic zoning within the melting region of the plume. The melting region constitutes only the innermost, highest-temperature part of the thermally anomalous plume mantle. The different ranges of values observed for each isotopic system, and comparison of Mauna Kea lavas with those of Mauna Loa, suggest that the axial region of the plume, which has a radius of ˜20 km, is a mixture of recycled subducted components and primitive lower mantle materials, recently combined during the formational stages of the plume at the base of the mantle. The proportions of recycled and primitive components are not constant, and this requires there be longitudinal (vertical) heterogeneity within the core of the plume. The remainder of the plume, outside this plume "core zone," is less heterogeneous but distinct from upper mantle as represented by mid-ocean ridge basalt (MORB). The plume structure may provide a detailed view of mantle isotopic composition near the core-mantle boundary.

Structure and dynamics of ND3BF3 in the solid and gas phases: a combined NMR, neutron diffraction, and Ab initio study.

PubMed

Penner, Glenn H; Ruscitti, Bruno; Reynolds, Julie; Swainson, Ian

2002-12-30

The decrease in D-->A bond lengths, previously reported for some Lewis acid/base complexes, in going from the gas to the solid phases is investigated by obtaining an accurate crystal structure of solid ND(3)BF(3) by powder neutron diffraction. The B-N internuclear distance is 1.554(3) A, 0.118 A shorter than the most recent gas-phase microwave value and 0.121 A shorter than the single molecule geometry optimized (1.672 A, CISD/6-311++G(d,p)) bond length. The crystal structure also shows N-D.F-B hydrogen bonds. The effects of this change in structure and of intermolecular hydrogen-bonding on nuclear magnetic shielding (i.e., chemical shifts) and the nuclear quadrupolar coupling constants (QCC) are investigated by ab initio molecular orbital and density functional theory calculations. These calculations show that the nitrogen ((15)N and (14)N) and boron ((11)B and (10)B) chemical shifts should be rather insensitive to changes in r(BN) and that the concomitant changes in molecular structure. Calculations on hydrogen-bonded clusters, based on the crystal structure, indicate that H-bonding should also have very little effect on the chemical shifts. On the other hand, the (11)B and (14)N QCCs show large changes because of both effects. An analysis of the (10)B[(19)F] line shape in solid ND(3)(10)BF(3) yields a (11)B QCC of +/-0.130 MHz. This is reasonably close an earlier value of +/-0.080 MHz and the value of +/-0.050 MHz calculated for a [NH(3)BF(3)](4) cluster. The gas-phase value is 1.20 MHz. Temperature-dependent deuterium T(1) measurements yield an activation energy for rotation of the ND(3) group in solid ND(3)BF(3) of 9.5 +/- 0.1 kJ/mol. Simulations of the temperature-dependent T(1) anisotropy gave an E(a) of 9.5 +/- 0.2 kJ/mol and a preexponential factor, A, of 3.0 +/- 0.1 x 10(12) s(-)(1). Our calculated value for a [NH(3)BF(3)](4) cluster is 16.4 kJ/mol. Both are much higher than the previous value of 3.9 kJ/mol, from solid-state proton T(1) measurements.

The value of bedside shift reporting enhancing nurse surveillance, accountability, and patient safety.

PubMed

Jeffs, Lianne; Acott, Ashley; Simpson, Elisa; Campbell, Heather; Irwin, Terri; Lo, Joyce; Beswick, Susan; Cardoso, Roberta

2013-01-01

A study was undertaken to explore nurses' experiences and perceptions associated with implementation of bedside nurse-to-nurse shift handoff reporting. Interviews were conducted with nurses and analyzed using directed content analysis. Two themes emerged that illustrated the value of bedside shift reporting. These themes included clarifying information and intercepting errors and visualizing patients and prioritizing care. Nurse leaders can leverage study findings in their efforts to embed nurse-to-nurse bedside shift reporting in their respective organizations.

What Drives Hydrogen Isotopic Variability Recorded by Biomarkers in Sediments of Lake Karakul, Pamir?

NASA Astrophysics Data System (ADS)

Aichner, B.; Mischke, S.; Pausata, F. S. R.; Werner, M.; Zhang, Q.; Heinecke, L.; Feakins, S. J.; Sachse, D.; Mahmoudov, Z.; Rajabov, I.

2017-12-01

Central Asia is a climate sensitive region located at the boundary of large scale atmospheric circulation systems. To examine glacial to interglacial hydrological changes in the region, we analysed the hydrogen isotopic composition (δD values) of n-alkanes in a 30-ka record from Lake Karakul, eastern Pamir (altitude: 3,915m, MAT: -3.9 °C, MAP: 82 mm). δD values of both aquatic and terrestrial compounds showed distinct trends throughout the studied time interval, with generally higher values during the glacial and lower values during the Holocene, and variability of up to 60‰. In particular shifts towards higher δD values were observed for aquatic biomarkers at ca. 30, 27, and 15 ka BP. Temperature and precipitation effects alone cannot explain the higher δD values during the glacial and the large isotopic amplitudes. To explain these observations we conducted a set of experiments using atmospheric models with embedded isotope modules (CAM3iso- and ECHAM5-wiso). We assume that terrestrial n-alkanes mainly record the isotopic signature of summer precipitation within the lower elevated parts of the Karakul Basin. Based on the model output we hypothesize that shifts between local and more distant vapour sources are the reason behind the trends within isotopic data. Data derived from aquatic biomarkers are more difficult to explain due to multiple influencing factors on δD of the lake water. Assuming that the lake water integrates an annual isotopic signal from the whole lake catchment, we suggest that a change in precipitation seasonality drives the large variability of hydrogen isotopic values. This is in agreement with the models, which suggest reduced winter (more negative δD) and slightly higher summer precipitation (more positive δD) during the glacial compared to the Holocene. Consequently, a net-increase of isotopically enriched inflow into the lake could explain the three distinct shifts towards higher δD values. Expansion of terrestrial vegetation, indicated by increasing biomarker concentrations, during these periods is another indicator for wetter summers in an arid environment. We conclude that δD values of terrestrial compounds reflect major shifts of vapour sources which are driven by insolation, while aquatic biomarkers are additionally influenced by changes of precipitation seasonality.

13C and 15N—Chemical Shift Anisotropy of Ampicillin and Penicillin-V Studied by 2D-PASS and CP/MAS NMR

NASA Astrophysics Data System (ADS)

Antzutkin, Oleg N.; Lee, Young K.; Levitt, Malcolm H.

1998-11-01

The principal values of the chemical shift tensors of all13C and15N sites in two antibiotics, ampicillin and penicillin-V, were determined by 2-dimensionalphaseadjustedspinningsideband (2D-PASS) and conventional CP/MAS experiments. The13C and15N chemical shift anisotropies (CSA), and their confidence limits, were evaluated using a Mathematica program. The CSA values suggest a revised assignment of the 2-methyl13C sites in the case of ampicillin. We speculate on a relationship between the chemical shift principal values of many of the13C and15N sites and the β-lactam ring conformation.

User's manual for computer program BASEPLOT

USGS Publications Warehouse

Sanders, Curtis L.

2002-01-01

The checking and reviewing of daily records of streamflow within the U.S. Geological Survey is traditionally accomplished by hand-plotting and mentally collating tables of data. The process is time consuming, difficult to standardize, and subject to errors in computation, data entry, and logic. In addition, the presentation of flow data on the internet requires more timely and accurate computation of daily flow records. BASEPLOT was developed for checking and review of primary streamflow records within the U.S. Geological Survey. Use of BASEPLOT enables users to (1) provide efficiencies during the record checking and review process, (2) improve quality control, (3) achieve uniformity of checking and review techniques of simple stage-discharge relations, and (4) provide a tool for teaching streamflow computation techniques. The BASEPLOT program produces tables of quality control checks and produces plots of rating curves and discharge measurements; variable shift (V-shift) diagrams; and V-shifts converted to stage-discharge plots, using data stored in the U.S. Geological Survey Automatic Data Processing System database. In addition, the program plots unit-value hydrographs that show unit-value stages, shifts, and datum corrections; input shifts, datum corrections, and effective dates; discharge measurements; effective dates for rating tables; and numeric quality control checks. Checklist/tutorial forms are provided for reviewers to ensure completeness of review and standardize the review process. The program was written for the U.S. Geological Survey SUN computer using the Statistical Analysis System (SAS) software produced by SAS Institute, Incorporated.

Equivalent circuit consideration of frequency-shift-type acceleration sensor

NASA Astrophysics Data System (ADS)

Sasaki, Yoshifumi; Sugawara, Sumio; Kudo, Subaru

2018-07-01

In this paper, an electrical equivalent circuit for the piezoelectrically driven frequency-shift-type acceleration sensor model is represented, and the equivalent circuit constants including the effect of the axial force are clarified for the first time. The results calculated by the finite element method are compared with the experimentally measured ones of the one-axis sensor of trial production. The result shows that the analyzed values almost agree with the measured ones, and that the equivalent circuit representation of the sensor is useful for electrical engineers in order to easily analyze the characteristics of the sensors.

Temperature Dependence of the Thermal Conductivity of Single Wall Carbon Nanotubes

NASA Technical Reports Server (NTRS)

Osman, Mohamed A.; Srivastava, Deepak

2000-01-01

The thermal conductivity of several single wall carbon nanotubes (CNT) has been calculated over a temperature range of 100-500 K using molecular dynamics simulations with Tersoff-Brenner potential for C-C interactions. In all cases, starting from similar values at 100K, thermal conductivities show a peaking behavior before falling off at higher temperatures. The peak position shifts to higher temperatures for nanotubes of larger diameter, and no significant dependence on the tube chirality is observed. It is shown that this phenomenon is due to onset of Umklapp scattering, which shifts to higher temperatures for nanotubes of larger diameter.

Role of 6-Mercaptopurine in the potential therapeutic targets DNA base pairs and G-quadruplex DNA: insights from quantum chemical and molecular dynamics simulations.

PubMed

Radhika, R; Shankar, R; Vijayakumar, S; Kolandaivel, P

2018-05-01

The theoretical studies on DNA with the anticancer drug 6-Mercaptopurine (6-MP) are investigated using theoretical methods to shed light on drug designing. Among the DNA base pairs considered, 6-MP is stacked with GC with the highest interaction energy of -46.19 kcal/mol. Structural parameters revealed that structure of the DNA base pairs is deviated from the planarity of the equilibrium position due to the formation of hydrogen bonds and stacking interactions with 6-MP. These deviations are verified through the systematic comparison between X-H bond contraction and elongation and the associated blue shift and red shift values by both NBO analysis and vibrational analysis. Bent's rule is verified for the C-H bond contraction in the 6-MP interacted base pairs. The AIM results disclose that the higher values of electron density (ρ) and Laplacian of electron density (∇ 2 ρ) indicate the increased overlap between the orbitals that represent the strong interaction and positive values of the total electron density show the closed-shell interaction. The relative sensitivity of the chemical shift values for the DNA base pairs with 6-MP is investigated to confirm the hydrogen bond strength. Molecular dynamics simulation studies of G-quadruplex DNA d(TGGGGT) 4 with 6-MP revealed that the incorporation of 6-MP appears to cause local distortions and destabilize the G-quadruplex DNA.

XRD and 29Si MAS-NMR spectroscopy across the β-Lu 2Si 2O 7- β-Y 2Si 2O 7 solid solution

NASA Astrophysics Data System (ADS)

Becerro, Ana I.; Escudero, Alberto

2005-01-01

Samples in the system Lu 2-xY xSi 2O 7 (0⩽ x⩽2) have been synthesized following the sol-gel method and calcined to 1300 °C, a temperature at which the β-polymorph is known to be the stable phase for the end-members Lu 2Si 2O 7 and Y 2Si 2O 7. The XRD patterns of all the compositions studied are compatible with the structure of the β-polymorph. Unit cell parameters are calculated as a function of composition from XRD patterns. They show a linear change with increasing Y content, which indicates a solid solubility of β-Y 2Si 2O 7 in β-Lu 2Si 2O 7 at 1300 °C. 29Si MAS NMR spectra of the different members of the system agree with the XRD results, showing a linear decrease of the 29Si chemical shift with increasing Y content. Finally, a correlation reported in the literature to predict 29Si chemical shifts in silicates is applied here to obtain the theoretical variation in 29Si chemical shift values in the system Lu 2Si 2O 7-Y 2Si 2O 7 and the results compare favorably with the values obtained experimentally.

Current and cumulative night shift work and subclinical atherosclerosis: results of the Gutenberg Health Study.

PubMed

Jankowiak, S; Backé, E; Liebers, F; Schulz, A; Hegewald, J; Garthus-Niegel, S; Nübling, M; Blankenberg, S; Pfeiffer, N; Lackner, K J; Beutel, M; Blettner, M; Münzel, T; Wild, P S; Seidler, A; Letzel, S; Latza, U

2016-11-01

The study examines the association between exposure to current and cumulative night shift work and subclinical parameters of atherosclerosis. Participants of a population-based cohort study (the Gutenberg Health Study, N = 15,010) aged 35-64 years were examined at baseline (2007-2012). Investigations included measurements of arterial stiffness, vascular function [reactive hyperaemia (RH) index], and intima media thickness (IMT). Also, a complete job history (including up to 15 periods), occupational exposures, a variety of lifestyle, and dispositional variables were enquired. Night shift work was performed by 1071 out of 8065 currently employed individuals. The strongest association after adjustment for age, sex, job complexity level, being a manager, overtime work, and noise appeared for more than 660 night shifts within the last 10 years and a significantly increased arterial stiffness of 0.33 m/s. This reflects a 4 % flow velocity increase for individuals with more than 660 night shifts compared to non-night workers. Regarding the entire professional life, night shift workers showed a significantly decreased vascular function by -0.054 RH index points by using the same adjustment. IMT values did not differ statistically from non-night workers. Lifestyle and dispositional factors showed an influence on all used subclinical atherosclerosis parameters. The cross-sectional results demonstrate an association between night work and detrimental changes in the atherosclerotic process. The association is more pronounced with more years in night shift and is partly explained by lifestyle and dispositional factors. Longitudinal analyses are necessary to confirm the results.

Evidence for an arene oxide-NIH shift pathway in the metabolic conversion of phenytoin to 5-(4-hydroxyphenyl)-5-phenylhydantoin in the rat and in man

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

Claesen, M.; Moustafa, M.A.; Adline, J.

To determine whether the hydroxylation of 5,5-diphenylhydantoin (DPH) to 5-(4-hydroxyphenyl)-5-phenylhydantoin (p-HPPH) occurs by an arene oxide-NIH shift process, racemic 5-(4-deuteriophenyl)-5-phenylhydantoin (p-2H-DPH) was subjected to in vivo metabolic experiments in the rat and in man. After enzymatic hydrolysis of the urine, para-hydroxylated metabolites were separated by HPLC. Deuterium retention in the isolated metabolites determined by gas chromatography-mass spectrometry, was 68-72%. The results are interpreted as the predominance of an arene oxide-NIH shift pathway in those two metabolic systems. Induction of rats with phenobarbital or 3-methylcholanthrene showed no effect on the value of deuterium retention.

Quantum-mechanics-derived 13Cα chemical shift server (CheShift) for protein structure validation

PubMed Central

Vila, Jorge A.; Arnautova, Yelena A.; Martin, Osvaldo A.; Scheraga, Harold A.

2009-01-01

A server (CheShift) has been developed to predict 13Cα chemical shifts of protein structures. It is based on the generation of 696,916 conformations as a function of the φ, ψ, ω, χ1 and χ2 torsional angles for all 20 naturally occurring amino acids. Their 13Cα chemical shifts were computed at the DFT level of theory with a small basis set and extrapolated, with an empirically-determined linear regression formula, to reproduce the values obtained with a larger basis set. Analysis of the accuracy and sensitivity of the CheShift predictions, in terms of both the correlation coefficient R and the conformational-averaged rmsd between the observed and predicted 13Cα chemical shifts, was carried out for 3 sets of conformations: (i) 36 x-ray-derived protein structures solved at 2.3 Å or better resolution, for which sets of 13Cα chemical shifts were available; (ii) 15 pairs of x-ray and NMR-derived sets of protein conformations; and (iii) a set of decoys for 3 proteins showing an rmsd with respect to the x-ray structure from which they were derived of up to 3 Å. Comparative analysis carried out with 4 popular servers, namely SHIFTS, SHIFTX, SPARTA, and PROSHIFT, for these 3 sets of conformations demonstrated that CheShift is the most sensitive server with which to detect subtle differences between protein models and, hence, to validate protein structures determined by either x-ray or NMR methods, if the observed 13Cα chemical shifts are available. CheShift is available as a web server. PMID:19805131

Assessing the system value of optimal load shifting

DOE PAGES

Merrick, James; Ye, Yinyu; Entriken, Bob

2017-04-30

We analyze a competitive electricity market, where consumers exhibit optimal load shifting behavior to maximize utility and producers/suppliers maximize their profit under supply capacity constraints. The associated computationally tractable formulation can be used to inform market design or policy analysis in the context of increasing availability of the smart grid technologies that enable optimal load shifting. Through analytic and numeric assessment of the model, we assess the equilibrium value of optimal electricity load shifting, including how the value changes as more electricity consumers adopt associated technologies. For our illustrative numerical case, derived from the Current Trends scenario of the ERCOTmore » Long Term System Assessment, the average energy arbitrage value per ERCOT customer of optimal load shifting technologies is estimated to be $3 for the 2031 scenario year. We assess the sensitivity of this result to the flexibility of load, along with its relationship to the deployment of renewables. Finally, the model presented can also be a starting point for designing system operation infrastructure that communicates with the devices that schedule loads in response to price signals.« less

Assessing the system value of optimal load shifting

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

Merrick, James; Ye, Yinyu; Entriken, Bob

We analyze a competitive electricity market, where consumers exhibit optimal load shifting behavior to maximize utility and producers/suppliers maximize their profit under supply capacity constraints. The associated computationally tractable formulation can be used to inform market design or policy analysis in the context of increasing availability of the smart grid technologies that enable optimal load shifting. Through analytic and numeric assessment of the model, we assess the equilibrium value of optimal electricity load shifting, including how the value changes as more electricity consumers adopt associated technologies. For our illustrative numerical case, derived from the Current Trends scenario of the ERCOTmore » Long Term System Assessment, the average energy arbitrage value per ERCOT customer of optimal load shifting technologies is estimated to be $3 for the 2031 scenario year. We assess the sensitivity of this result to the flexibility of load, along with its relationship to the deployment of renewables. Finally, the model presented can also be a starting point for designing system operation infrastructure that communicates with the devices that schedule loads in response to price signals.« less

Melatonin and cortisol assessment of circadian shifts in astronauts before flight

NASA Technical Reports Server (NTRS)

Whitson, P. A.; Putcha, L.; Chen, Y. M.; Baker, E.

1995-01-01

Melatonin and cortisol were measured in saliva and urine samples to assess the effectiveness of a 7-day protocol combining bright-light exposure with sleep shifting in eliciting a 12-hr phase-shift delay in eight U.S. Space Shuttle astronauts before launch. Baseline acrophases for 15 control subjects with normal sleep-wake cycles were as follows: cortisol (saliva) at 0700 (0730 in urine); melatonin (saliva) at 0130 (6-hydroxymelatonin sulfate at 0230 in urine). Acrophases of the astronaut group fell within 2.5 hr of these values before the treatment protocols were begun. During the bright-light and sleep-shifting treatments, both absolute melatonin production and melatonin rhythmicity were diminished during the first 3 treatment days; total daily cortisol levels remained constant throughout the treatment. By the fourth to sixth day of the 7-day protocol, seven of the eight crew members showed phase delays in all four measures that fell within 2 hr of the expected 11- to 12-hr shift. Although cortisol and melatonin rhythms each corresponded with the phase shift, the rhythms in these two hormones did not correspond with each other during the transition.

Melatonin and cortisol assessment of circadian shifts in astronauts before flight.

PubMed

Whitson, P A; Putcha, L; Chen, Y M; Baker, E

1995-04-01

Melatonin and cortisol were measured in saliva and urine samples to assess the effectiveness of a 7-day protocol combining bright-light exposure with sleep shifting in eliciting a 12-hr phase-shift delay in eight U.S. Space Shuttle astronauts before launch. Baseline acrophases for 15 control subjects with normal sleep-wake cycles were as follows: cortisol (saliva) at 0700 (0730 in urine); melatonin (saliva) at 0130 (6-hydroxymelatonin sulfate at 0230 in urine). Acrophases of the astronaut group fell within 2.5 hr of these values before the treatment protocols were begun. During the bright-light and sleep-shifting treatments, both absolute melatonin production and melatonin rhythmicity were diminished during the first 3 treatment days; total daily cortisol levels remained constant throughout the treatment. By the fourth to sixth day of the 7-day protocol, seven of the eight crew members showed phase delays in all four measures that fell within 2 hr of the expected 11- to 12-hr shift. Although cortisol and melatonin rhythms each corresponded with the phase shift, the rhythms in these two hormones did not correspond with each other during the transition.

Protein Structure Validation and Refinement Using Amide Proton Chemical Shifts Derived from Quantum Mechanics

PubMed Central

Christensen, Anders S.; Linnet, Troels E.; Borg, Mikael; Boomsma, Wouter; Lindorff-Larsen, Kresten; Hamelryck, Thomas; Jensen, Jan H.

2013-01-01

We present the ProCS method for the rapid and accurate prediction of protein backbone amide proton chemical shifts - sensitive probes of the geometry of key hydrogen bonds that determine protein structure. ProCS is parameterized against quantum mechanical (QM) calculations and reproduces high level QM results obtained for a small protein with an RMSD of 0.25 ppm (r = 0.94). ProCS is interfaced with the PHAISTOS protein simulation program and is used to infer statistical protein ensembles that reflect experimentally measured amide proton chemical shift values. Such chemical shift-based structural refinements, starting from high-resolution X-ray structures of Protein G, ubiquitin, and SMN Tudor Domain, result in average chemical shifts, hydrogen bond geometries, and trans-hydrogen bond (h3 JNC') spin-spin coupling constants that are in excellent agreement with experiment. We show that the structural sensitivity of the QM-based amide proton chemical shift predictions is needed to obtain this agreement. The ProCS method thus offers a powerful new tool for refining the structures of hydrogen bonding networks to high accuracy with many potential applications such as protein flexibility in ligand binding. PMID:24391900

QCD phase diagram using PNJL model with eight-quark interactions

NASA Astrophysics Data System (ADS)

Deb, Paramita; Bhattacharyya, Abhijit; Ghosh, Sanjay K.; Ray, Rajarshi; Lahiri, Anirban

2011-07-01

We present the phase diagram and the fluctuations of different conserved charges like quark number, charge and strangeness at vanishing chemical potential for the 2+1 flavor Polyakov Loop extended Nambu-Jona-Lasinio model with eight-quark interaction terms using three-momentum cutoff regularisation. The main effect of the higher order interaction term is to shift the critical end point to the lower value of the chemical potential and higher value of the temperature. The fluctuations show good qualitative agreement with the lattice data.

Spectroscopic study of trivalent praseodymium in barium yttrium fluoride

NASA Astrophysics Data System (ADS)

Bowlby, Brian Edward

1998-09-01

This work investigates the spectroscopic properties of trivalent praseodymium (Pr3+) in barium yttrium fluoride (BaY2F8). Two doping concentrations were studied: BaY2F8:Pr3+ (.3%) and BaY2F8:Pr3+ (1%). Absorption spectra were taken at 77K and 300K and these were then used to calculate the Judd-Ofelt coefficients for both samples. These coefficients were then used to calculate the theoretical lifetimes and radiative branching ratios for all manifolds. Continuous luminescence spectra and lifetime measurements were also performed, and from these, experimentally determined values for the branching ratio and lifetimes were determined. These were then compared to their theoretical counterparts. It was found that while the theory gave values that were qualitatively correct, the quantitative correlation between theory and experiment shows the complexity of the physical reality and the difficulty of synthesizing an encompassing theoretical model. Absorption spectra and continuous luminescence spectra were also used to determine the energy levels of all manifolds in both samples. A total of 59 energy levels in 11 manifolds were identified in the BaY2F8:Pr3+ (1%) sample, while 51 levels in 11 manifolds were identified in the BaY2F8:Pr3+ (.3%) sample. Finally, the effects of temperature on the line width and line position for several radiative transitions was studied. It was found that while most transitions exhibited the expected broadening and shifting towards longer wavelengths at higher temperatures (a 'red shift'), the transition from the 3P0 level to the 3H4 ground state showed a shift towards shorter wavelengths at higher temperature (a 'blue shift'). Again this highlights the complexity of the ion- host interaction.

Dynamic response of peatbank moss communities to hydroclimate over the last 2000 years in the western Antarctic Peninsula

NASA Astrophysics Data System (ADS)

Stelling, J.; Yu, Z.; Beilman, D. W.

2016-12-01

The western Antarctic Peninsula experienced rapid warming in late half of the 20th century in part due to a positive phase of the Southern Annular Mode (SAM) causing poleward expansion of the southern westerly wind belt that brings warmer and moister air to the peninsula. However, we do not know how coastal terrestrial ecosystems have responded to changes in temperature and hydroclimate. Here we present a paleoecological and geochemical record of ecosystem history derived from late Holocene peatbank deposits on Litchfield Island (64°46'S; 64°06'W) to reconstruct terrestrial response to temperature and hydroclimate fluctuations. Chronology of our 80-cm-long peat core from the north-facing slope is constrained by 11 AMS 14C dates covering the last 2500 years. Our macrofossil results show that relative abundance of the two dominant moss species fluctuates between <10 and 90%. Furthermore, the δ13C values of bulk peat range from -26.4 to -22.1‰ that mostly reflects species relative abundance change through time. The periods with C:N values of <20—lower than the expected C:N values (40 to 80) of fresh moss plants—corresponds with intervals containing abundant fine debris (>50%), indicating greater decomposition and selective removal of carbon from peat. Our record shows that periods where moss dominance shifts to Polytrichum, a dry and cold tolerant moss, peat decomposition increases, and coincides with periods of negative SAM. Conversely, dominance shifts to Chorisodontium, a less drought tolerant moss, with decomposition decreased during periods of strong positive SAM. This study demonstrates that ecosystem structure and geochemical signature within these moss peatbanks is sensitive to regional moisture change that can potentially be used to reconstruct shifts in hydroclimate and possibly atmospheric circulation.

Isotopic Investigation of Contemporary and Historic Changes in Penguin Trophic Niches and Carrying Capacity of the Southern Indian Ocean

PubMed Central

Jaeger, Audrey; Cherel, Yves

2011-01-01

A temperature-defined regime shift occurred in the 1970s in the southern Indian Ocean, with simultaneous severe decreases in many predator populations. We tested a possible biological link between the regime shift and predator declines by measuring historic and contemporary feather isotopic signatures of seven penguin species with contrasted foraging strategies and inhabiting a large latitudinal range. We first showed that contemporary penguin isotopic variations and chlorophyll a concentration were positively correlated, suggesting the usefulness of predator δ13C values to track temporal changes in the ecosystem carrying capacity and its associated coupling to consumers. Having controlled for the Suess effect and for increase CO2 in seawater, δ13C values of Antarctic penguins and of king penguins did not change over time, while δ13C of other subantarctic and subtropical species were lower in the 1970s. The data therefore suggest a decrease in ecosystem carrying capacity of the southern Indian Ocean during the temperature regime-shift in subtropical and subantarctic waters but not in the vicinity of the Polar Front and in southward high-Antarctic waters. The resulting lower secondary productivity could be the main driving force explaining the decline of subtropical and subantarctic (but not Antarctic) penguins that occurred in the 1970s. Feather δ15N values did not show a consistent temporal trend among species, suggesting no major change in penguins’ diet. This study highlights the usefulness of developing long-term tissue sampling and data bases on isotopic signature of key marine organisms to track potential changes in their isotopic niches and in the carrying capacity of the environment. PMID:21311756

Isotopic investigation of contemporary and historic changes in penguin trophic niches and carrying capacity of the southern Indian ocean.

PubMed

Jaeger, Audrey; Cherel, Yves

2011-02-02

A temperature-defined regime shift occurred in the 1970s in the southern Indian Ocean, with simultaneous severe decreases in many predator populations. We tested a possible biological link between the regime shift and predator declines by measuring historic and contemporary feather isotopic signatures of seven penguin species with contrasted foraging strategies and inhabiting a large latitudinal range. We first showed that contemporary penguin isotopic variations and chlorophyll a concentration were positively correlated, suggesting the usefulness of predator δ¹³C values to track temporal changes in the ecosystem carrying capacity and its associated coupling to consumers. Having controlled for the Suess effect and for increase CO₂ in seawater, δ¹³C values of Antarctic penguins and of king penguins did not change over time, while δ¹³C of other subantarctic and subtropical species were lower in the 1970s. The data therefore suggest a decrease in ecosystem carrying capacity of the southern Indian Ocean during the temperature regime-shift in subtropical and subantarctic waters but not in the vicinity of the Polar Front and in southward high-Antarctic waters. The resulting lower secondary productivity could be the main driving force explaining the decline of subtropical and subantarctic (but not Antarctic) penguins that occurred in the 1970s. Feather δ¹⁵N values did not show a consistent temporal trend among species, suggesting no major change in penguins' diet. This study highlights the usefulness of developing long-term tissue sampling and data bases on isotopic signature of key marine organisms to track potential changes in their isotopic niches and in the carrying capacity of the environment.

Results of crack-arrest tests on irradiated a 508 class 3 steel

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

Iskander, S.K.; Milella, P.P.; Pini, M.A.

1998-02-01

Ten crack-arrest toughness values for irradiated specimens of A 508 class 3 forging steel have been obtained. The tests were performed according to the American Society for Testing and Materials (ASTM) Standard Test Method for Determining Plane-Strain Crack-Arrest Fracture Toughness, K{sub la} of Ferritic Steels, E 1221-88. None of these values are strictly valid in all five ASTM E 1221-88 validity criteria. However, they are useful when compared to unirradiated crack-arrest specimen toughness values since they show the small (averaging approximately 10{degrees}C) shifts in the mean and lower-bound crack-arrest toughness curves. This confirms that a low copper content in ASTMmore » A 508 class 3 forging material can be expected to result in small shifts of the transition toughness curve. The shifts due to neutron irradiation of the lower bound and mean toughness curves are approximately the same as the Charpy V-notch (CVN) 41-J temperature shift. The nine crack-arrest specimens were irradiated at temperatures varying from 243 to 280{degrees}C, and to a fluence varying from 1.7 to 2.7 x 10{sup 19} neutrons/cm{sup 2} (> 1 MeV). The test results were normalized to reference values that correspond to those of CVN specimens irradiated at 284{degrees}C to a fluence of 3.2 x 10{sup 19} neutrons/cm{sup 2} (> 1 MeV) in the same capsule as the crack-arrest specimens. This adjustment resulted in a shift to lower temperatures of all the data, and in particular moved two data points that appeared to lie close to or lower than the American Society of Mechanical Engineers K{sub la} curve to positions that seemed more reasonable with respect to the remaining data. A special fixture was designed, fabricated, and successfully used in the testing. For reasons explained in the text, special blocks to receive the Oak Ridge National Laboratory clip gage were designed, and greater-than-standard crack-mouth opening displacements measured were accounted for. 24 refs., 13 figs., 12 tabs.« less

Effects of Solder Volume and Reflow Conditions on Self-Alignment Accuracy for Fan-Out Package Applications

NASA Astrophysics Data System (ADS)

Park, Hwan-Pil; Seo, Gwancheol; Kim, Sungchul; Kim, Young-Ho

2018-01-01

The effects of solder volume and reaction time between molten solder and a metal pad at the peak temperature of reflow on the self-alignment effect have been investigated in flip chip bonding. A glass die with two different pad designs and a flame retardant-4 (FR-4) organic substrate were used. Sn-3.0Ag-0.5Cu and Sn-3.5Ag solders were formed on Cu-organic solderability preservation (Cu-OSP) and electroless nickel electroless palladium immersion gold (ENEPIG) pads on FR-4 substrates using the stencil printing method. To assess the effect of solder volume, the thickness and opening size of the stencil mask were controlled. Reflow experiments were performed at 250°C with wetting times of 40 s, 55 s, 65 s, and 75 s. After flip chip reflow soldering, the bonding areas were cross-sectioned to inspect the shape of the interconnected solder using scanning electron microscopy. The results revealed that using an insufficient solder volume on the pad was responsible for die shifts larger than 1 μm, while a sufficient solder volume on the pad and a stable solder joint shape could ensure misalignment less than 1 μm. The Sn-3.0Ag-0.5Cu solder showed a lower die shift value than the Sn-3.5Ag solder because the Sn-3.0Ag-0.5Cu solder has stronger surface tension than the Sn-3.5Ag solder. Using a longer wetting time between the solder and the pad at the peak temperature also improved the die shift value because the increased reaction time changed the interconnected solder shape between the die and substrate from concave to convex, moving the die to a more accurate position. Furthermore, the restoring forces on die self-alignment influenced the die shift value. A stronger solder surface tension and a larger volume of solder on the pad produced stronger restoring forces for die self-alignment, thereby improving the die shift value.

Algorithm based on regional separation for automatic grain boundary extraction using improved mean shift method

NASA Astrophysics Data System (ADS)

Zhenying, Xu; Jiandong, Zhu; Qi, Zhang; Yamba, Philip

2018-06-01

Metallographic microscopy shows that the vast majority of metal materials are composed of many small grains; the grain size of a metal is important for determining the tensile strength, toughness, plasticity, and other mechanical properties. In order to quantitatively evaluate grain size in metals, grain boundaries must be identified in metallographic images. Based on the phenomenon of grain boundary blurring or disconnection in metallographic images, this study develops an algorithm based on regional separation for automatically extracting grain boundaries by an improved mean shift method. Experimental observation shows that the grain boundaries obtained by the proposed algorithm are highly complete and accurate. This research has practical value because the proposed algorithm is suitable for grain boundary extraction from most metallographic images.

Context for Education in the Seventies.

ERIC Educational Resources Information Center

Harman, Willis W.

Three forces are pushing man toward a drastic shift in cultural values and basic premises. These are: 1) the existence of a world macroproblem which requires such a shift for its solution; 2) the "great refusal" of youth to go along with the values of the past; and 3) the questioning within science as to whether its classical "value-free" stance…

Regular and platform switching: bone stress analysis varying implant type.

PubMed

Gurgel-Juarez, Nália Cecília; de Almeida, Erika Oliveira; Rocha, Eduardo Passos; Freitas, Amílcar Chagas; Anchieta, Rodolfo Bruniera; de Vargas, Luis Carlos Merçon; Kina, Sidney; França, Fabiana Mantovani Gomes

2012-04-01

This study aimed to evaluate stress distribution on peri-implant bone simulating the influence of platform switching in external and internal hexagon implants using three-dimensional finite element analysis. Four mathematical models of a central incisor supported by an implant were created: External Regular model (ER) with 5.0 mm × 11.5 mm external hexagon implant and 5.0 mm abutment (0% abutment shifting), Internal Regular model (IR) with 4.5 mm × 11.5 mm internal hexagon implant and 4.5 mm abutment (0% abutment shifting), External Switching model (ES) with 5.0 mm × 11.5 mm external hexagon implant and 4.1 mm abutment (18% abutment shifting), and Internal Switching model (IS) with 4.5 mm × 11.5 mm internal hexagon implant and 3.8 mm abutment (15% abutment shifting). The models were created by SolidWorks software. The numerical analysis was performed using ANSYS Workbench. Oblique forces (100 N) were applied to the palatal surface of the central incisor. The maximum (σ(max)) and minimum (σ(min)) principal stress, equivalent von Mises stress (σ(vM)), and maximum principal elastic strain (ε(max)) values were evaluated for the cortical and trabecular bone. For cortical bone, the highest stress values (σ(max) and σ(vm) ) (MPa) were observed in IR (87.4 and 82.3), followed by IS (83.3 and 72.4), ER (82 and 65.1), and ES (56.7 and 51.6). For ε(max), IR showed the highest stress (5.46e-003), followed by IS (5.23e-003), ER (5.22e-003), and ES (3.67e-003). For the trabecular bone, the highest stress values (σ(max)) (MPa) were observed in ER (12.5), followed by IS (12), ES (11.9), and IR (4.95). For σ(vM), the highest stress values (MPa) were observed in IS (9.65), followed by ER (9.3), ES (8.61), and IR (5.62). For ε(max) , ER showed the highest stress (5.5e-003), followed by ES (5.43e-003), IS (3.75e-003), and IR (3.15e-003). The influence of platform switching was more evident for cortical bone than for trabecular bone, mainly for the external hexagon implants. In addition, the external hexagon implants showed less stress concentration in the regular and switching platforms in comparison to the internal hexagon implants. © 2012 by the American College of Prosthodontists.

SU-E-J-06: A Time Dependence Analysis of CBCT Image Quality and Mechanical Stability.

PubMed

Oves, S; Stenbeck, J; Gebreamlak, W; Alkhatib, H

2012-06-01

To quantify the change, if any, in flexmap correction factors and image quality with the XVI system over a course of several years and from these results, assess their clinical impact. Flexmap, a calibration procedure which corrects for imperfect gantry rotation for cone-beam CT reconstruction, and image quality tests were performed on three Elekta Synergy linacs equipped with XVI. Data was collected per month over three years. U and V values, corresponding to lateral and longitudinal shifts respectively, were acquired through the XVI software. Image quality parameters were obtained through CT imaging of the Catphan 500®. For each reconstruction, pixel values for low density polyethylene (LDPE) and polystyrene materials were recorded. For all three linacs, analysis of the flexmap showed a significant change in the U factor for both month-to-month comparisons and comparisons between machines. The V correction factor exhibited a small variation month to month, and showed a slight, gradual increase over time (0.2 +/-0.08 mm). Image quality analysis showed a near consistent decrease (5-10%) in LDPE and polystyrene. Despite this decrease in pixel values, the ratio of the two pixel values remained constant, thus a similar decreasing trend in contrast was not observed. Analysis of monthly flexmap calibration showed the general monthly change in correction shifts and their general trend over several years. For image quality, our research exhibited roughly 0.5% per month decrease in pixel values of the Catphan®. Our results imply that CBCT images obtained from XVI are not appropriate for treatment planning and despite the decrease in panel response over time, image quality with respect to contrast will remain within acceptable clinical standards. Future studies may be carried out to assess any correlation between image quality and XVI source strength. © 2012 American Association of Physicists in Medicine.

"Meta-analyses and P-curves support robust cycle shifts in women's mate preferences: Reply to Wood and Carden (2014) and Harris, Pashler, and Mickes (2014)": Correction to Gildersleeve, Haselton, and Fales (2014).

PubMed

2017-11-01

Reports an error in "Meta-analyses and p -curves support robust cycle shifts in women's mate preferences: Reply to Wood and Carden (2014) and Harris, Pashler, and Mickes (2014)" by Kelly Gildersleeve, Martie G. Haselton and Melissa R. Fales ( Psychological Bulletin , 2014[Sep], Vol 140[5], 1272-1280). In the article, all p -curve analyses examining the Context Moderation Hypothesis Prediction mistakenly included the p-value from Little, Jones, Burt, & Perrett (2007) Study 2 for the simple effect of fertility on attraction to facial symmetry in a short-term relationship context ( p < .001). The analyses should have instead included the p -value for the fertility X relationship context interaction ( p = .011). In addition, the p -curve analyses examining exact two-tailed p -values for the Cycle Shift Prediction should have included an additional p -value from Provost et al. (2008) Study 1 for the main effect of fertility on attraction to gait masculinity. The reported p -value for this effect was .05, making it ineligible for inclusion in p -curves of reported p-values. However, the exact recalculated two-tailed p -value was .049, making it eligible for inclusion in p -curves of exact p -values. The corrected p -curve of exact two-tailed p -values evaluating the Cycle Shift Prediction and Context Moderation Prediction (displayed in Figure 2) now includes a total of 15 p -values ( N = 1442) is no longer significantly right skewed χ²(30) = 41.25, p = .08. The corrected p -curve of exact two-tailed p -values evaluating the Cycle Shift Prediction, Context Moderation Prediction, and Partner Qualities Moderation Prediction (displayed in Figure 3) now includes a total of 21 p -values ( N = 1707) and continues to be significantly right skewed Χ²(42) = 69.83, p = .004. As part of this correction, the online supplemental materials have been updated. (The following abstract of the original article appeared in record 2014-35938-003.) Two meta-analyses evaluated shifts across the ovulatory cycle in women's mate preferences but reported very different findings. In this journal, we reported robust evidence for the pattern of cycle shifts predicted by the ovulatory shift hypothesis (Gildersleeve, Haselton, & Fales, 2014). However, Wood, Kressel, Joshi, and Louie (2014) claimed an absence of compelling support for this hypothesis and asserted that the few significant cycle shifts they observed were false positives resulting from publication bias, p-hacking, or other research artifacts. How could 2 meta-analyses of the same literature reach such different conclusions? We reanalyzed the data compiled by Wood et al. These analyses revealed problems in Wood et al.'s meta-analysis-some of which are reproduced in Wood and Carden's (2014) comment in the current issue of this journal-that led them to overlook clear evidence for the ovulatory shift hypothesis in their own set of effects. In addition, we present right-skewed p-curves that directly contradict speculations by Wood et al.; Wood and Carden; and Harris, Pashler, and Mickes (2014) that supportive findings in the cycle shift literature are false positives. Therefore, evidence from both of the meta-analyses and the p-curves strongly supports genuine, robust effects consistent with the ovulatory shift hypothesis and contradicts claims that these effects merely reflect publication bias, p-hacking, or other research artifacts. Unfounded speculations about p-hacking distort the research record and risk unfairly damaging researchers' reputations; they should therefore be made only on the basis of firm evidence. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Valley-orbit splitting in doped nanocrystalline silicon: k•p calculations

NASA Astrophysics Data System (ADS)

Belyakov, Vladimir A.; Burdov, Vladimir A.

2007-07-01

The valley-orbit splitting in silicon quantum dots with shallow donors has been theoretically studied. In particular, the chemical-shift calculation was carried out within the frames of k•p approximation for single- and many-donor cases. For both cases, the great value of the chemical shift has been obtained compared to its bulk value. Such increase of the chemical shift becomes possible due to the quantum confinement effect in a dot. It is shown for the single-donor case that the level splitting and chemical shift strongly depend on the dot radius and donor position inside the nanocrystal. In the many-donor case, the chemical shift is almost proportional to the number of donors.

Monitoring of land degradation from overgrazing using space-borne radar and optical imagery: a case study in Randi Forest, Cyprus

NASA Astrophysics Data System (ADS)

Papoutsa, C.; Kouhartsiouk, D.; Themistocleous, K.; Christoforou, M.; Hadjimitsis, D. G.

2016-10-01

This paper examines how radar and optical imagery combined can be employed for the study of land degradation. A case study was conducted in the Randi Forest, Cyprus, a known overgrazed area for the past 70 years. Satellite optical imagery was used for the calculation of the Normalised Difference Vegetation Index (NDVI) for the time period between December 2015 to July 2016 and C-Band Synthetic Aperture Radar imagery was used to derive correlative changes in backscatter intensity (σ0). The results are indicative of the overgrazing in the area with the temporal and spatial variations of grazing defined. Both the NDVI and the σ0 values demonstrate sudden shifts in vegetation cover following the start of the grazing period with the greatest shifts being evident in close proximity to the location of farms. NDVI and backscatter coefficient correlation was measured at 0.7 and 0.8 for the months of February and April respectively. Shifts in NDVI value by 0.1 correspond to a shift in σ0 by 4 db. VH cross-polarization showed greater sensitivity to changes in vegetation than VV. The paper also examines the capability of C-Band Synthetic Aperture Radar to measure changes in plant structure and vegetation fraction as the result of grazing. Depending on grazing intensity, backscatter coefficient varies according to vegetation density.

Executive summary: value-based purchasing and technology assessment in orthopaedics.

PubMed

Ranawat, Anil S; Nunley, Ryan; Bozic, Kevin

2009-10-01

As US healthcare expenditures continue to rise, reform has shifted from spending controls to value-based purchasing. This paradigm shift is a drastic change on how health care is delivered and reimbursed. For the shift to work, policymakers and physicians must restructure the present system by using initiatives such as process reengineering, insurance and payment reforms, physician reeducation, data and quality measurements, and technology assessments. Value, as defined in economic terms, will be a critical concept in modern healthcare reform. We summarize the conclusions of this ABJS Carl T. Brighton Workshop on healthcare reform.

Tissue specific resonance frequencies of water and metabolites within the human brain

NASA Astrophysics Data System (ADS)

Chadzynski, Grzegorz L.; Bender, Benjamin; Groeger, Adriane; Erb, Michael; Klose, Uwe

2011-09-01

Chemical shift imaging (CSI) without water suppression was used to examine tissue-specific resonance frequencies of water and metabolites within the human brain. The aim was to verify if there are any regional differences in those frequencies and to determine the influence of chemical shift displacement in slice-selection direction. Unsuppressed spectra were acquired at 3 T from nine subjects. Resonance frequencies of water and after water signal removal of total choline, total creatine and NAA were estimated. Furthermore, frequency distances between the water and those resonances were calculated. Results were corrected for chemical shift displacement. Frequency distances between water and metabolites were consistent and greater for GM than for WM. The highest value of WM to GM difference (14 ppb) was observed for water to NAA frequency distance. This study demonstrates that there are tissue-specific differences between frequency distances of water and metabolites. Moreover, the influence of chemical shift displacement in slice-selection direction is showed to be negligible.

Tissue specific resonance frequencies of water and metabolites within the human brain.

PubMed

Chadzynski, Grzegorz L; Bender, Benjamin; Groeger, Adriane; Erb, Michael; Klose, Uwe

2011-09-01

Chemical shift imaging (CSI) without water suppression was used to examine tissue-specific resonance frequencies of water and metabolites within the human brain. The aim was to verify if there are any regional differences in those frequencies and to determine the influence of chemical shift displacement in slice-selection direction. Unsuppressed spectra were acquired at 3T from nine subjects. Resonance frequencies of water and after water signal removal of total choline, total creatine and NAA were estimated. Furthermore, frequency distances between the water and those resonances were calculated. Results were corrected for chemical shift displacement. Frequency distances between water and metabolites were consistent and greater for GM than for WM. The highest value of WM to GM difference (14ppb) was observed for water to NAA frequency distance. This study demonstrates that there are tissue-specific differences between frequency distances of water and metabolites. Moreover, the influence of chemical shift displacement in slice-selection direction is showed to be negligible. Copyright © 2011 Elsevier Inc. All rights reserved.

Admission medical records made at night time have the same quality as day and evening time records.

PubMed

Amirian, Ilda; Mortensen, Jacob F; Rosenberg, Jacob; Gögenur, Ismail

2014-07-01

A thorough and accurate admission medical record is an important tool in ensuring patient safety during the hospital stay. Surgeons' performance might be affected during night shifts due to sleep deprivation. The aim of the study was to assess the quality of admission medical records during day, evening and night time. A total of 1,000 admission medical records were collected from 2009 to 2013 based equally on four diagnoses: mechanical bowel obstruction, appendicitis, gallstone disease and gastrointestinal bleeding. The records were reviewed for errors by a pre-defined checklist based on Danish standards for admission medical records. The time of dictation for the medical record was registered. A total of 1,183 errors were found in 778 admission medical records made during day- and evening time, and 322 errors in 222 admission medical records from night time shifts. No significant overall difference in error was found in the admission medical records when day and evening values were compared to night values. Subgroup analyses made for all four diagnoses showed no difference in day and evening values compared with night time values. Night time deterioration was not seen in the quality of the medical records.

Shifts in the Budyko curve over the past decade in the Amazon basin

NASA Astrophysics Data System (ADS)

Maeda, E. E.; Ma, X.; Liu, Y.; Huete, A. R.

2017-12-01

The Amazon basin has experienced extensive forest loss during the past decades. These changes can exert significant impact on regional water and energy budget, as well as other environmental processes. Here we evaluated how forest loss in the Madeira and Tapajós River basins, between 2002 and 2015, affected the Budyko relationship. The Budyko framework describes the links between climate and hydrological components, where evapotranspiration (ET) is limited by the supply of either water or energy. The framework is composed by two components, the dryness index (DI) and the evaporative index (EI). The DI determines the type and degree of limitation, with values lower than 1 represent energy-limited condition and values higher than 1, water-limited. The EI describes the partitioning of rainfall (P) into ET and runoff (R), with higher values indicating a larger proportion of ET. In this study, we use a modified version of the Budyko framework, which accounts for intra-annual changes in water storage (dS). Hence, the effective rainfall is represented by P-dS, so that EI=ET/(P-dS) and the DI= PET/(P-dS). We show that the Madeira and Tapajós River basins have lost approximately 60000 km2 and 50000km2 of forested area by 2015, respectively. Our results indicate that these changes caused a subtle shift in the Budyko curve in both basins. At the Madeira basin, a reduction in the DI indicate a shift towards lower water limitation, while decreasing EI indicate that a higher proportion of P is being converted into runoff. At the Tapajós basin, we also observe an overall decrease in the DI, but no significant trends in the evaporative index was observed. We expect that the observed shifts provide a new insight on the Amazon forest responses to changes in climate and land use. Further studies will focus in identifying the biophysical mechanisms driving these shifts, as well as seasonal aspects of the changes.

Retrospective characterization of ontogenetic shifts in killer whale diets via δ13C and δ15N analysis of teeth

USGS Publications Warehouse

Newsome, Seth D.; Etnier, Michael A.; Monson, Daniel H.; Fogel, Marilyn L.

2009-01-01

Metabolically inert, accretionary structures such as the dentin growth layers in teeth provide a life history record of individual diet with near-annual resolution. We constructed ontogenetic ??13C and ??15N profiles by analyzing tooth dentin growth layers from 13 individual killer whales Orcinus orca collected in the eastern northeast Pacific Ocean between 1961 and 2003. The individuals sampled were 6 to 52 yr old, representing 2 ecotypes-resident and transient - collected across ???25?? of latitude. The average isotopic values of transient individuals (n = 10) are consistent with a reliance on mammalian prey, while the average isotopic values of residents (n = 3) are consistent with piscivory. Regardless of ecotype, most individuals show a decrease in ??15N values of ???2.5% through the first 3 yr of life, roughly equivalent to a decrease of one trophic level. We interpret this as evidence of gradual weaning, after which, ontogenetic shifts in isotopic values are highly variable. A few individuals (n = 2) maintained relatively stable ??15N and ??13C values throughout the remainder of their lives, whereas ??15N values of most (n = 11) increased by ???1.5%, suggestive of an ontogenetic increase in trophic level. Significant differences in mean ??13C and ??15N values among transients collected off California suggest that individuality in prey preferences may be prevalent within this ecotype. Our approach provides retrospective individual life history and dietary information that cannot be obtained through traditional field observations of free-ranging and elusive species such as killer whales, including unique historic ecological information that pre-dates modern studies. By providing insights into individual diet composition, stable isotope analysis of teeth and/or bones may be the only means of evaluating a number of hypothesized historical dietary shifts in killer whales of the northeast Pacific Ocean. ?? Inter-Research 2009.

Retrospective characterization of ontogenetic shifts in killer whale diets via δ13C and δ15N analysis of teeth

USGS Publications Warehouse

Newsome, Seth D.; Etnier, Michael A.; Monson, Daniel H.; Fogel, Marilyn L.

2009-01-01

Metabolically inert, accretionary structures such as the dentin growth layers in teeth provide a life history record of individual diet with near-annual resolution. We constructed ontogenetic δ13C and δ15N profiles by analyzing tooth dentin growth layers from 13 individual killer whales Orcinus orca collected in the eastern northeast Pacific Ocean between 1961 and 2003. The individuals sampled were 6 to 52 yr old, representing 2 ecotypes—resident and transient—collected across ~25° of latitude. The average isotopic values of transient individuals (n = 10) are consistent with a reliance on mammalian prey, while the average isotopic values of residents (n = 3) are consistent with piscivory. Regardless of ecotype, most individuals show a decrease in δ15N values of ~2.5‰ through the first 3 yr of life, roughly equivalent to a decrease of one trophic level. We interpret this as evidence of gradual weaning, after which, ontogenetic shifts in isotopic values are highly variable. A few individuals (n = 2) maintained relatively stable δ15N and δ13C values throughout the remainder of their lives, whereas δ15N values of most (n = 11) increased by ~1.5‰, suggestive of an ontogenetic increase in trophic level. Significant differences in mean δ13C and δ15N values among transients collected off California suggest that individuality in prey preferences may be prevalent within this ecotype. Our approach provides retrospective individual life history and dietary information that cannot be obtained through traditional field observations of free-ranging and elusive species such as killer whales, including unique historic ecological information that pre-dates modern studies. By providing insights into individual diet composition, stable isotope analysis of teeth and/or bones may be the only means of evaluating a number of hypothesized historical dietary shifts in killer whales of the northeast Pacific Ocean

Theoretical investigation on ratiometric two-photon fluorescent probe for Zn2+ detection based on ICT mechanism

NASA Astrophysics Data System (ADS)

Huang, Shuang; Yang, Bao-Zhu; Ren, Ai-Min

2016-06-01

OPA (one-photon absorption), TPA (two-photon absorption) and fluorescence properties of a free ligand L upon coordination with Zn2+, and the regeneration with CN- were investigated in theory. According to our research, OPA spectra of ligand L show red-shift binding with Zn2+ while blue-shift with CN-. The fluorescence spectra and TPA wavelength are shifted in the same situation as those of OPA spectra. The value of TPA cross-section decreased at first, and then increased to 1813 GM for [L-Zn(CN)4]2-. Intramolecular charge transfer (ICT) mechanism was investigated by natural bond orbital (NBO) analysis. It demonstrates that L is hopeful to be a good ratiometric fluorescent probe for zinc ion detection in solution, and it can regenerate after CN- was introduced.

Deep To Shallow, Time Transgressive Shift In The Source Of Bottom Waters On Demerara Rise Inferred From Neodymium Isotopes In Fish Debris

NASA Astrophysics Data System (ADS)

Isaza-Londoño, C.; MacLeod, K. G.; Martin, E. E.; Jiménez Berrocoso

2008-12-01

Between the Campanian and Danian, ɛNd values of fish debris from four sites on Demerara Rise (tropical North Atlantic) shift by ~5 units from -16 to -11. Low values from Campanian and early Maastrichtian samples are similar to values measured on most other Late Cretaceous samples from Demerara sites, whereas the post-shift values are similar to Late Cretaceous and Paleogene values observed at a number of other North Atlantic deep sea sites. In addition, at the two relatively deep sites studied (Ocean Drilling Program [ODP] Sites 1258 and 1260), the shift begins near the base of the Maastrichtian Abathomphalus mayaroensis planktonic foraminifera Zone and values increase over an interval representing several million years of deposition. In two relatively shallow sites (OSP Sites 1259 and 1261), on the other hand, ɛNd values remain low through the highest Cretaceous samples measured, which are from near the top of the Abathomphalus mayaroensis Zone. Therefore, low values persist for several million years longer at the shallower sites. At Site 1259, no Paleogene samples have been analyzed yet, but at Site 1261 values shift from ~-16.5 to ~-13 in samples separated by ~3.5 m and bracketing the Cretaceous/Paleogene (K/T) boundary. Unfortunately, the K/T boundary is not complete at Site 1261, so the relationship to the K/T event is unclear. Ongoing work is focused on constraining the relationship between ɛNd shifts and the K/T boundary using the more complete record at Site 1259 and at examining whether there is any high frequency variation superimposed on the gradual trends observed, especially at the deeper sites. Regardless of the outcome of the these analyses, assuming the low ɛNd values characteristic of most the Late Cretaceous on Demerara Rise are the signature of a locally formed intermediate water mass, the existing data already indicate that the importance of downwelling in the tropical North Atlantic began to wane in the mid- Maastrichtian and had apparently ceased by the earliest Paleogene.

Impact of hydrostatic pressure on an intrinsically disordered protein: a high-pressure NMR study of α-synuclein.

PubMed

Roche, Julien; Ying, Jinfa; Maltsev, Alexander S; Bax, Ad

2013-09-23

The impact of pressure on the backbone (15) N, (1) H and (13) C chemical shifts in N-terminally acetylated α-synuclein has been evaluated over a pressure range 1-2500 bar. Even while the chemical shifts fall very close to random coil values, as expected for an intrinsically disordered protein, substantial deviations in the pressure dependence of the chemical shifts are seen relative to those in short model peptides. In particular, the nonlinear pressure response of the (1) H(N) chemical shifts, which commonly is associated with the presence of low-lying "excited states", is much larger in α-synuclein than in model peptides. The linear pressure response of (1) H(N) chemical shift, commonly linked to H-bond length change, correlates well with those in short model peptides, and is found to be anticorrelated with its temperature dependence. The pressure dependence of (13) C chemical shifts shows remarkably large variations, even when accounting for residue type, and do not point to a clear shift in population between different regions of the Ramachandran map. However, a nearly universal decrease in (3) JHN-Hα by 0.22 ± 0.05 Hz suggests a slight increase in population of the polyproline II region at 2500 bar. The first six residues of N-terminally acetylated synuclein show a transient of approximately 15% population of α-helix, which slightly diminishes at 2500 bar. The backbone dynamics of the protein is not visibly affected beyond the effect of slight increase in water viscosity at 2500 bar. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of the relative shift between the electron density and temperature pedestal position on the pedestal stability in JET-ILW and comparison with JET-C

NASA Astrophysics Data System (ADS)

Stefanikova, E.; Frassinetti, L.; Saarelma, S.; Loarte, A.; Nunes, I.; Garzotti, L.; Lomas, P.; Rimini, F.; Drewelow, P.; Kruezi, U.; Lomanowski, B.; de la Luna, E.; Meneses, L.; Peterka, M.; Viola, B.; Giroud, C.; Maggi, C.; contributors, JET

2018-05-01

The electron temperature and density pedestals tend to vary in their relative radial positions, as observed in DIII-D (Beurskens et al 2011 Phys. Plasmas 18 056120) and ASDEX Upgrade (Dunne et al 2017 Plasma Phys. Control. Fusion 59 14017). This so-called relative shift has an impact on the pedestal magnetohydrodynamic (MHD) stability and hence on the pedestal height (Osborne et al 2015 Nucl. Fusion 55 063018). The present work studies the effect of the relative shift on pedestal stability of JET ITER-like wall (JET-ILW) baseline low triangularity (δ) unseeded plasmas, and similar JET-C discharges. As shown in this paper, the increase of the pedestal relative shift is correlated with the reduction of the normalized pressure gradient, therefore playing a strong role in pedestal stability. Furthermore, JET-ILW tends to have a larger relative shift compared to JET carbon wall (JET-C), suggesting a possible role of the plasma facing materials in affecting the density profile location. Experimental results are then compared with stability analysis performed in terms of the peeling-ballooning model and with pedestal predictive model EUROPED (Saarelma et al 2017 Plasma Phys. Control. Fusion). Stability analysis is consistent with the experimental findings, showing an improvement of the pedestal stability, when the relative shift is reduced. This has been ascribed mainly to the increase of the edge bootstrap current, and to minor effects related to the increase of the pedestal pressure gradient and narrowing of the pedestal pressure width. Pedestal predictive model EUROPED shows a qualitative agreement with experiment, especially for low values of the relative shift.

Method for the manufacture of phase shifting masks for EUV lithography

DOEpatents

Stearns, Daniel G.; Sweeney, Donald W.; Mirkarimi, Paul B.; Barty, Anton

2006-04-04

A method for fabricating an EUV phase shift mask is provided that includes a substrate upon which is deposited a thin film multilayer coating that has a complex-valued reflectance. An absorber layer or a buffer layer is attached onto the thin film multilayer, and the thickness of the thin film multilayer coating is altered to introduce a direct modulation in the complex-valued reflectance to produce phase shifting features.

Focal shift and the axial optical coordinate for high-aperture systems of finite Fresnel number.

PubMed

Sheppard, Colin J R; Török, Peter

2003-11-01

Analytic expressions are given for the on-axis intensity predicted by the Rayleigh-Sommerfeld and Kirchhoff diffraction integrals for a scalar optical system of high numerical aperture and finite value of Fresnel number. A definition of the axial optical coordinate is introduced that is valid for finite values of Fresnel number, for high-aperture systems, and for observation points distant from the focus. The focal shift effect is reexamined. For the case when the focal shift is small, explicit expressions are given for the focal shift and the axial peak in intensity.

Combined Monte Carlo and quantum mechanics study of the solvatochromism of phenol in water. The origin of the blue shift of the lowest pi-pi* transition.

PubMed

Barreto, Rafael C; Coutinho, Kaline; Georg, Herbert C; Canuto, Sylvio

2009-03-07

A combined and sequential use of Monte Carlo simulations and quantum mechanical calculations is made to analyze the spectral shift of the lowest pi-pi* transition of phenol in water. The solute polarization is included using electrostatic embedded calculations at the MP2/aug-cc-pVDZ level giving a dipole moment of 2.25 D, corresponding to an increase of 76% compared to the calculated gas-phase value. Using statistically uncorrelated configurations sampled from the MC simulation, first-principle size-extensive calculations are performed to obtain the solvatochromic shift. Analysis is then made of the origin of the blue shift. Results both at the optimized geometry and in room-temperature liquid water show that hydrogen bonds of water with phenol promote a red shift when phenol is the proton-donor and a blue shift when phenol is the proton-acceptor. In the case of the optimized clusters the calculated shifts are in very good agreement with results obtained from mass-selected free jet expansion experiments. In the liquid case the contribution of the solute-solvent hydrogen bonds partially cancels and the total shift obtained is dominated by the contribution of the outer solvent water molecules. Our best result, including both inner and outer water molecules, is 570 +/- 35 cm(-1), in very good agreement with the small experimental shift of 460 cm(-1) for the absorption maximum.

Chemical Mass Shifts in a Digital Linear Ion Trap as Analytical Identity of o-, m-, and p-Xylene.

PubMed

Sun, Lulu; Xue, Bing; Huang, Zhengxu; Cheng, Ping; Ma, Li; Ding, Li; Zhou, Zhen

2018-07-01

Chemical mass shifts between isomeric ions of o-, m-, and p-xylene were measured using a digital linear ion trap, and the directions and values of the shifts were found to be correlated to the collision cross sections of the isomers. Both forward and reverse scans were used and the chemical shifts for each pair of isomers in scans of opposite directions were in opposite signs. Using different voltage settings (namely the voltage dividing ratio-VDR) of the ion trap allows adding high order field components in the quadrupole field and results in larger chemical mass shifts. The differential chemical mass shift which combined the shifts from forward and reverse scans doubled the amount of chemical shift, e.g., 0.077 Th between o- and p-xylene, enough for identification of the type of isomer without using an additional ion mobility spectrometer. The feature of equal and opposite chemical mass shifts also allowed to null out the chemical mass shift by calculating the mean m/z value between the two opposite scans and remove or reduce the mass error caused by chemical mass shift. Graphical Abstract ᅟ.

Chemical Mass Shifts in a Digital Linear Ion Trap as Analytical Identity of o-, m-, and p-Xylene

NASA Astrophysics Data System (ADS)

Sun, Lulu; Xue, Bing; Huang, Zhengxu; Cheng, Ping; Ma, Li; Ding, Li; Zhou, Zhen

2018-04-01

Chemical mass shifts between isomeric ions of o-, m-, and p-xylene were measured using a digital linear ion trap, and the directions and values of the shifts were found to be correlated to the collision cross sections of the isomers. Both forward and reverse scans were used and the chemical shifts for each pair of isomers in scans of opposite directions were in opposite signs. Using different voltage settings (namely the voltage dividing ratio-VDR) of the ion trap allows adding high order field components in the quadrupole field and results in larger chemical mass shifts. The differential chemical mass shift which combined the shifts from forward and reverse scans doubled the amount of chemical shift, e.g., 0.077 Th between o- and p-xylene, enough for identification of the type of isomer without using an additional ion mobility spectrometer. The feature of equal and opposite chemical mass shifts also allowed to null out the chemical mass shift by calculating the mean m/z value between the two opposite scans and remove or reduce the mass error caused by chemical mass shift. [Figure not available: see fulltext.

Dominant role of many-body effects on the carrier distribution function of quantum dot lasers

NASA Astrophysics Data System (ADS)

Peyvast, Negin; Zhou, Kejia; Hogg, Richard A.; Childs, David T. D.

2016-03-01

The effects of free-carrier-induced shift and broadening on the carrier distribution function are studied considering different extreme cases for carrier statistics (Fermi-Dirac and random carrier distributions) as well as quantum dot (QD) ensemble inhomogeneity and state separation using a Monte Carlo model. Using this model, we show that the dominant factor determining the carrier distribution function is the free carrier effects and not the choice of carrier statistics. By using empirical values of the free-carrier-induced shift and broadening, good agreement is obtained with experimental data of QD materials obtained under electrical injection for both extreme cases of carrier statistics.

Under conditions of large geometric miss, tumor control probability can be higher for static gantry intensity-modulated radiation therapy compared to volume-modulated arc therapy for prostate cancer.

PubMed

Balderson, Michael; Brown, Derek; Johnson, Patricia; Kirkby, Charles

2016-01-01

The purpose of this work was to compare static gantry intensity-modulated radiation therapy (IMRT) with volume-modulated arc therapy (VMAT) in terms of tumor control probability (TCP) under scenarios involving large geometric misses, i.e., those beyond what are accounted for when margin expansion is determined. Using a planning approach typical for these treatments, a linear-quadratic-based model for TCP was used to compare mean TCP values for a population of patients who experiences a geometric miss (i.e., systematic and random shifts of the clinical target volume within the planning target dose distribution). A Monte Carlo approach was used to account for the different biological sensitivities of a population of patients. Interestingly, for errors consisting of coplanar systematic target volume offsets and three-dimensional random offsets, static gantry IMRT appears to offer an advantage over VMAT in that larger shift errors are tolerated for the same mean TCP. For example, under the conditions simulated, erroneous systematic shifts of 15mm directly between or directly into static gantry IMRT fields result in mean TCP values between 96% and 98%, whereas the same errors on VMAT plans result in mean TCP values between 45% and 74%. Random geometric shifts of the target volume were characterized using normal distributions in each Cartesian dimension. When the standard deviations were doubled from those values assumed in the derivation of the treatment margins, our model showed a 7% drop in mean TCP for the static gantry IMRT plans but a 20% drop in TCP for the VMAT plans. Although adding a margin for error to a clinical target volume is perhaps the best approach to account for expected geometric misses, this work suggests that static gantry IMRT may offer a treatment that is more tolerant to geometric miss errors than VMAT. Copyright © 2016 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

Self-Broadening and Self-Shift Coefficients in the Fundamental Band of 12C 16O

NASA Technical Reports Server (NTRS)

Devi, Malathy V.; Benner, D. Chris; Smith, Mary Ann H.; Rinsland, Curtis P.

1998-01-01

High quality and precise measurements of self-broadened and self-shift coefficients in the fundamental band of C-12O-16 were made using spectra recorded at room temperature with the high-resolution (0.0027 cm(exp -1)) McMath-Pierce Fourier transform spectrometer located at the National Solar Observatory on Kitt Peak, Arizona. The spectral region under investigation (2008-2247 cm(exp -1)) contains the P(31) to R(31) transitions. The data were obtained using a high-purity natural isotopic sample ofcarbon monoxide and two absorption cells with pathlengths of 4.08 and 9.98 cm, respectively. Various pressures of CO were used, ranging between 0.25 and 201.2 Torr. The results were obtained by analyzing five spectra simultaneously, using a multispectrum nonlinear least-squares fitting technique. The self-broadened coefficients ranged from 0.0426(2) cm(exp -1) atm(exp -1) at 296 K to 0.0924(2) cm(exp -1) atm(exp -1) at 296 K, while the pressure-induced shift coefficients varied between -0.0042(3) cm(exp -1) atm(exp -1) at 296 K and +0.0005(l) cm(exp -1) atm(exp -1) at 296 K. The value in parentheses is the estimated uncertainty in units of the last digit. The self-broadened coefficients of lines with same values of m in the P and R branches agree close to within experimental uncertainties while the self-shift coefficients showed considerable variation within and between the two branches. The mean value of the ratios of P branch to R branch self-broadened coefficients was found to be 1.01 with a standard deviation of + or - 0.01. Comparisons of the results with other published data were made.

Estimation of Δ R/ R values by benchmark study of the Mössbauer Isomer shifts for Ru, Os complexes using relativistic DFT calculations

NASA Astrophysics Data System (ADS)

Kaneko, Masashi; Yasuhara, Hiroki; Miyashita, Sunao; Nakashima, Satoru

2017-11-01

The present study applies all-electron relativistic DFT calculation with Douglas-Kroll-Hess (DKH) Hamiltonian to each ten sets of Ru and Os compounds. We perform the benchmark investigation of three density functionals (BP86, B3LYP and B2PLYP) using segmented all-electron relativistically contracted (SARC) basis set with the experimental Mössbauer isomer shifts for 99Ru and 189Os nuclides. Geometry optimizations at BP86 theory of level locate the structure in a local minimum. We calculate the contact density to the wavefunction obtained by a single point calculation. All functionals show the good linear correlation with experimental isomer shifts for both 99Ru and 189Os. Especially, B3LYP functional gives a stronger correlation compared to BP86 and B2PLYP functionals. The comparison of contact density between SARC and well-tempered basis set (WTBS) indicated that the numerical convergence of contact density cannot be obtained, but the reproducibility is less sensitive to the choice of basis set. We also estimate the values of Δ R/ R, which is an important nuclear constant, for 99Ru and 189Os nuclides by using the benchmark results. The sign of the calculated Δ R/ R values is consistent with the predicted data for 99Ru and 189Os. We obtain computationally the Δ R/ R values of 99Ru and 189Os (36.2 keV) as 2.35×10-4 and -0.20×10-4, respectively, at B3LYP level for SARC basis set.

Learning-Induced Plasticity in Medial Prefrontal Cortex Predicts Preference Malleability

PubMed Central

Garvert, Mona M.; Moutoussis, Michael; Kurth-Nelson, Zeb; Behrens, Timothy E.J.; Dolan, Raymond J.

2015-01-01

Summary Learning induces plasticity in neuronal networks. As neuronal populations contribute to multiple representations, we reasoned plasticity in one representation might influence others. We used human fMRI repetition suppression to show that plasticity induced by learning another individual’s values impacts upon a value representation for oneself in medial prefrontal cortex (mPFC), a plasticity also evident behaviorally in a preference shift. We show this plasticity is driven by a striatal “prediction error,” signaling the discrepancy between the other’s choice and a subject’s own preferences. Thus, our data highlight that mPFC encodes agent-independent representations of subjective value, such that prediction errors simultaneously update multiple agents’ value representations. As the resulting change in representational similarity predicts interindividual differences in the malleability of subjective preferences, our findings shed mechanistic light on complex human processes such as the powerful influence of social interaction on beliefs and preferences. PMID:25611512

Formation of Gd-Al Alloy Films by a Molten Salt Electrochemical Process

NASA Astrophysics Data System (ADS)

Caravaca, Concha; De Córdoba, Guadalupe

2008-02-01

The electrochemistry of molten LiCl-KCl-GdCl3 at a reactive Al electrode has been studied at 723 to 823 K. Electrochemical techniques such as cyclic voltammetry and chronopotentiometry have been used in order to identify the intermetallic compounds formed. Cyclic voltammetry showed that, while at an inert W electrode GdCl3 is reduced to Gd metal in a single step at a potential close to the reduction of the solvent, at an Al electrode a shift towards more positive values occurs. This shift of the cathodic potential indicated a reduction of the activity of Gd in Al with respect to that ofW, due to the formation of alloys. The surface characterization of samples formed by both galvanostatic and potentiostatic electrolysis has shown the presence of two intermetallic compounds: GdAl3 and GdAl2. Using open-circuit chronopotentiometry it has been possible to measure the potentials at which these compounds are transformed into each other. The values of these potential plateaus, once transformed into e. f. m. values, allowed to determine the thermodynamic properties of the GdAl3 intermetallic compound.

Calculation of 125Te NMR Chemical Shifts at the Full Four-Component Relativistic Level with Taking into Account Solvent and Vibrational Corrections: A Gateway to Better Agreement with Experiment.

PubMed

Rusakova, Irina L; Rusakov, Yuriy Yu; Krivdin, Leonid B

2017-06-29

Four-component relativistic calculations of 125 Te NMR chemical shifts were performed in the series of 13 organotellurium compounds, potential precursors of the biologically active species, at the density functional theory level under the nonrelativistic and four-component fully relativistic conditions using locally dense basis set scheme derived from relativistic Dyall's basis sets. The relativistic effects in tellurium chemical shifts were found to be of as much as 20-25% of the total calculated values. The vibrational and solvent corrections to 125 Te NMR chemical shifts are about, accordingly, 6 and 8% of their total values. The PBE0 exchange-correlation functional turned out to give the best agreement of calculated tellurium shifts with their experimental values giving the mean absolute percentage error of 4% in the range of ∼1000 ppm, provided all corrections are taken into account.

Sentimental value and its influence on hedonic adaptation.

PubMed

Yang, Yang; Galak, Jeff

2015-11-01

Sentimental value is a highly prevalent, yet largely understudied phenomenon. We introduce the construct of sentimental value and investigate how and why sentimental value influences hedonic adaptation. Across 7 studies, we examine the antecedents of sentimental value and demonstrate its effect on hedonic adaptation using both naturally occurring and experimentally manipulated items with sentimental value. We further test the underlying process linking sentimental value and hedonic adaptation by showing that whereas feature-related utility decreases for all items with time, sentimental value typically does not, and that sentimental value moderates the influence of the decrement in feature-related utility on hedonic adaptation. Moreover, this moderating effect of sentimental value is driven by a shift in focus from features of the item to the associations that item possess. We conclude with a discussion of related phenomena and implications for individuals. (c) 2015 APA, all rights reserved).

Chroma Shift and Gamut Shape: Going Beyond Average Color Fidelity and Gamut Area

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

Royer, Michael P.; Houser, Kevin W.; David, Aurelien

Though sometimes referred to as a two-measure system for evaluating color rendition, IES TM-30-15 includes key components that go beyond the two high-level average values, Fidelity Index (IES Rf) and Gamut Index (IES Rg). This article focuses on the Color Vector Graphic and Local Chroma Shift (IES Rcs,hj), discussing the calculation methods for these evaluation tools and providing context for the interpretation of the values. We illustrate why and how the Color Vector Graphic and Local Chroma Shift values capture information about color rendition that is impossible to describe with average measures (such as CIE Ra, IES Rf, or IESmore » Rg), but that is pertinent to more completely quantifying color rendition, and to understanding human evaluations of color quality in the built environment. We also present alternatives for quantifying the Color Vector Graphic and Local Chroma Shift values, which can inform the development of future measures.« less

Making value a priority: how this paradigm shift is changing the landscape in health care.

PubMed

Kimberly, John; Cronk, Imran

2016-10-01

The world of health care is changing dramatically, as reflected in the number, magnitude, and scope of innovative new approaches-to how illness is treated and how better health is promoted-that are being implemented around the globe. The changes triggered by these initiatives affect both how care is organized, managed, and paid for and the kinds of approaches that are being developed to keep people healthy. Underlying these changes is a more fundamental paradigm shift, a shift in the priority given to "value" in the formulation of policy and management practice. This brief essay highlights five trends that are central in this shift: increasing emphasis on health promotion, movement toward value-based payment, advances in digital/mobile technology, exploitation of big data, and changes in support for biomedical research. Each of these has its own value controversies, and the individual impact of each is impossible to predict. Collectively, however, their impact is likely to be significant. © 2016 New York Academy of Sciences.

Sum-over-states density functional perturbation theory: Prediction of reliable 13C, 15N, and 17O nuclear magnetic resonance chemical shifts

NASA Astrophysics Data System (ADS)

Olsson, Lars; Cremer, Dieter

1996-11-01

Sum-over-states density functional perturbation theory (SOS-DFPT) has been used to calculate 13C, 15N, and 17O NMR chemical shifts of 20 molecules, for which accurate experimental gas-phase values are available. Compared to Hartree-Fock (HF), SOS-DFPT leads to improved chemical shift values and approaches the degree of accuracy obtained with second order Møller-Plesset perturbation theory (MP2). This is particularly true in the case of 15N chemical shifts where SOS-DFPT performs even better than MP2. Additional improvements of SOS-DFPT chemical shifts can be obtained by empirically correcting diamagnetic and paramagnetic contributions to compensate for deficiencies which are typical of DFT.

Water-gas shift reaction on alumina-supported Pt-CeO x catalysts prepared by supercritical fluid deposition

DOE PAGES

Deal, Jacob W.; Le, Phong; Corey, C. Blake; ...

2016-08-25

Alumina-supported platinum catalysts, both with and without ceria, were prepared by supercritical fluid deposition and evaluated for activity for water-gas shift reaction. The organometallic precursor, platinum(II) acetylacetonate, was deposited from solution in supercritical carbon dioxide. Analysis of the catalysts by high resolution scanning transmission electron microscopy indicated that platinum was present in the form of highly dispersed metal nanoparticles. Pretreatment of the alumina-supported ceria in hydrogen prior to the deposition of the platinum precursor resulted in more platinum nucleated on ceria than non-pretreated alumina-supported ceria but varied in both particle size and structure. The ceria-containing catalyst that was not pretreatedmore » exhibited a more uniform particle size, and the Pt particles were encapsulated in crystalline ceria. Reaction rate measurements showed that the catalyst was more active for water-gas shift, with reaction rates per mass of platinum that exceeded most literature values for water-gas shift reaction on Pt-CeO x catalysts. The high activity was attributed to the significant fraction of platinum/ceria interfacial contact. We found that these results show the promise of supercritical fluid deposition as a scalable means of synthesizing highly active supported metal catalysts that offer efficient utilization of precious metals.« less

About the relevance of waviness, agglomeration, and strain on the electrical behavior of polymer composites filled with carbon nanotubes evaluated by a Monte-Carlo simulation

NASA Astrophysics Data System (ADS)

Román, Sebastián; Lund, Fernando; Bustos, Javier; Palza, Humberto

2018-01-01

In several technological applications, carbon nanotubes (CNT) are added to a polymer matrix in order to develop electrically conductive composite materials upon percolation of the CNT network. This percolation state depends on several parameters such as particle characteristics, degree of dispersion, and filler orientation. For instance, CNT aggregation is currently avoided because it is thought that it will have a negative effect on the electrical behavior despite some experimental evidence showing the contrary. In this study, the effect of CNT waviness, degree of agglomeration, and external strain, on the electrical percolation of polymer composites is studied by a three dimensional Monte-Carlo simulation. The simulation shows that the percolation threshold of CNT depends on the particle waviness, with rigid particles displaying the lowest values. Regarding the effect of CNT dispersion, our numerical results confirm that low levels of agglomeration reduce the percolation threshold of the composite. However, the threshold is shifted to larger values at high agglomeration states because of the appearance of isolated areas of high CNT concentrations. These results imply, therefore, an optimum of agglomeration that further depends on the waviness and concentration of CNT. Significantly, CNT agglomeration can further explain the broad percolation transition found in these systems. When an external strain is applied to the composites, the percolation concentration shifts to higher values because CNT alignment increases the inter-particle distances. The strain sensitivity of the composites is affected by the percolation state of CNT showing a maximum value at certain filler concentration. These results open up the discussion about the relevance in polymer composites of the dispersion state of CNT and filler flexibility towards electrically conductive composites.

Chroma Shift and Gamut Shape: Going Beyond Average Color Fidelity and Gamut Area

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

Royer, Michael P.; Houser, Kevin W.; David, Aurélien

Though sometimes referred to as a two-measure system for evaluating color rendition, IES TM-30-15 includes other key components that go beyond the high-level average values IES Rf and IES Rg. This article focuses on the Color Vector Graphic and Local Chroma Shift (IES Rcs,hj), discussing the calculation methods for these evaluation tools and providing context for the interpretation of the values. It also presents alternatives for quantifying the same characteristics, which can inform the development of future measures. The Color Vector Graphic (CVG) is a visual representation of hue and chroma shifts across different hues. It quickly communicates complex informationmore » about how object colors will be rendered by a light source, although it is difficult or impossible to use for writing a specification. CVGs demonstrate that increases in chroma for certain hues sometimes means a decrease in chroma for other hues, and illustrates hue shifts for intermediate colors. The combination of shifts over different hues can be referred to as gamut shape. Complementing this information are the IES Rcs,hj values, which quantify the average relative chroma shift for samples in each of the 16 hue-angle bins (j) specified in IES TM-30-15. Unlike measures of average color fidelity and gamut area, gamut shape and hue-specific chroma shift are new concepts with no directly-comparable historical references. It will be critical to incorporate the Color Vector Graphic and Local Chroma Shift values into practice because they capture information about color rendition that is impossible to describe with average measures (such as CIE Ra, IES Rf, or IES Rg), but that is critical to understanding human evaluations of color quality in architectural environments.« less

Validation of a Questionnaire to Screen for Shift Work Disorder

PubMed Central

Barger, Laura K.; Ogeil, Rowan P.; Drake, Christopher L.; O'Brien, Conor S.; Ng, Kim T.; Rajaratnam, Shantha M. W.

2012-01-01

Study Objective: At least 15% of the full-time work force is shift workers. Working during the overnight hours, early morning start times, and variable or rotating schedules present a challenge to the circadian system, and these shifts are associated with adverse health and safety consequences. Shift work disorder (SWD), a primary (circadian rhythm) sleep disorder indicated by excessive daytime sleepiness and/or insomnia associated with a shiftwork schedule, is under-recognized by primary care physicians. We sought to develop and validate a questionnaire to screen for high risk of SWD in a shift working population. Design: Shift workers completed a 26-item questionnaire and were evaluated by a sleep specialist (physician) who diagnosed them as either positive or negative for SWD. The physician assessment of SWD was guided by a flow chart that operationalized the ICSD-2 criteria for SWD. Setting: 18 sleep clinics in the USA. Patients or Participants: 311 shift workers. Interventions: Not applicable. Measurements and Results: Responses to the items in the questionnaire were entered into a series of discrimination function analyses to determine the diagnostic value of the items and the fewest number of questions with the best predictive value. The function was then cross-validated. A final 4-item questionnaire has 89% positive predictive value and 62% negative predictive value (sensitivity = 0.74; specificity = 0.82). Conclusions: This Shiftwork Disorder Screening Questionnaire may be appropriate for use in primary care settings to aid in the diagnosis of SWD. Citation: Barger LK; Ogeil RP; Drake CL; O'Brien CS; Ng KT; Rajaratnam SMW. Validation of a questionnaire to screen for shift work disorder. SLEEP 2012;35(12):1693–1703. PMID:23204612

Predictive power of the DASA-IV: Variations in rating method and timescales.

PubMed

Nqwaku, Mphindisi; Draycott, Simon; Aldridge-Waddon, Luke; Bush, Emma-Louise; Tsirimokou, Alexandra; Jones, Dominic; Puzzo, Ignazio

2018-05-10

This project evaluated the predictive validity of the Dynamic Appraisal of Situational Aggression - Inpatient Version (DASA-IV) in a high-secure psychiatric hospital in the UK over 24 hours and over a single nursing shift. DASA-IV scores from three sequential nursing shifts over a 24-hour period were compared with the mean (average of three scores across the 24-hour period) and peak (highest of the three scores across the 24-hour period) scores across these shifts. In addition, scores from a single nursing shift were used to predict aggressive incidents over each of the following three shifts. The DASA-IV was completed by nursing staff during handover meetings, rating 43 male psychiatric inpatients over a period of 6 months. Data were compared to incident reports recorded over the same period. Receiver operating characteristic (ROC) curves and generalized estimating equations assessed the predictive ability of various DASA-IV scores over 24-hour and single-shift timescales. Scores from the DASA-IV based on a single shift had moderate predictive ability for aggressive incidents occurring the next calendar day, whereas scores based on all three shifts had excellent predictive ability. DASA-IV scores from a single shift showed moderate predictive ability for each of the following three shifts. The DASA-IV has excellent predictive ability for aggressive incidents within a secure setting when data are summarized over a 24-hour period, as opposed to when a single rating is taken. In addition, it has moderate value for predicting incidents over even shorter timescales. © 2018 Australian College of Mental Health Nurses Inc.

Effect of pH shifts on IgE-binding capacity and conformational structure of tropomyosin from short-neck clam (Ruditapes philippinarum).

PubMed

Lin, Haixin; Li, Zhenxing; Lin, Hong; Song, Yongna; Lv, Liangtao; Hao, Zina

2015-12-01

The aim of the present study was to assess pH-induced changes in conformational structures and potential allergenicity of tropomyosin from short-neck clams. As defined with circular dichroism (CD), an unfolded structure was found at pH values ranging from 2.0 to 5.0, followed by the loss of secondary structure at pH of 1.0. Correspondingly, surface hydrophobicity was reduced by 97.7% when pH was reduced from 7.0 to 1.0. Further indirect ELISA and dot-blot results of pH shifted tropomyosin showed that potential allergenicity correlated well with structural changes, as well as with SGF digestibility. Allergenicity decreased significantly with unfolding of the protein and was stable when surface hydrophobicity recovered back to neutral conditions. These results showed that conformational changes in tropomyosin induced by pH shifting significantly influenced the allergenicity of tropomyosin, and that the resulting changes occurred predominately in the acidic pH range. Copyright © 2015 Elsevier Ltd. All rights reserved.

Measurement and significance of the reversal potential for the pace-maker current (iK2) in sheep Purkinje fibres.

PubMed

DiFrancesco, D; Ohba, M; Ojeda, C

1979-12-01

1. The apparent reversal potential (Erev) of the pace-maker current (iK2) is found to depend on the experimental protocol used for its measurement. Evidence is presented showing that depolarizing (hyperpolarizing) pulses given before a test hyperpolarization used to determine Erev, shift Erev to more negative (positive) values. These shifts are opposite to those expected if the only effect of pre-pulses were to change the concentration of potassium in extracellular clefts ([K]c) via accumulation and depletion processes. 2. This effect is shown to be due to the fact that Erev is dependent on s0, the degree of activation of iK2 at the start of the test hyperpolarization. 3. When a suitable protocol is used, depletion of cleft K can be demonstrated to take place during a large hyperpolarization. Changes in the level of [K]c induced by pre-pulses must therefore also affect the Erev determination. 4. A simplified three-compartment model has been used to investigate how K accumulation and depletion can affect the time course of iK2, with particular reference to the problem of Erev determination. Computed examples show that the model is able to reproduce the main features of the time course of iK2 recorded near its reversal potential and the changes induced by pre-pulses on Erev measuremnet. By contrast, simulation on a linear cable model rules out the possibility that such results are due to voltage non-uniformity. 5. The three-compartment model predicts that the measured value of Erev differs from EK2 for two reasons: (1) when the recorded current trace is flat iK2 is still outward and decaying, and (2) the K equilibrium potential shifts to more negative values while the test hyperpolarization is applied. 6. The finding that Erev is directly affected by changes in s at the beginning of the test pulse is discussed in relation to the action of agents (such as Ca2+, H+, salicylate, adrenaline and ouabain) which are found to shift both the s00 curve and Erev.

Shifts in Ross Sea food web structure as indicated by δ15N and δ13C values of fossil Antarctic seals

NASA Astrophysics Data System (ADS)

Leopold, A.; Brault, E.; McMahon, K.

2013-12-01

As climate change continues to mount, there is a growing need for understanding its effects on biological-physical interactions of marine ecosystems. Assessing the effects of anthropogenic activities on the coastal marine ecosystem involves understanding the underlying mechanisms driving these changes as well as establishing baselines of the natural system. Preliminary findings have indicated shifts in bulk carbon (C) and nitrogen (N) isotopic values of southern elephant seal (Mirounga leonina) samples, collected in the Dry Valleys of Antarctica in the Ross Sea region, over approximately the last 7,000 years. These shifts could result from 1) seals changing their foraging location and/or diet over this time, 2) climate change-induced shifts in the biogeochemistry at the base of the food web, or 3) some combination of both processes. We explored the patterns of long-term change in Ross Sea food web structure by examining the stable isotope values of three top predators in this system, Weddell seals (Leptonychotes weddellii), leopard seals (Hydrurga leptonyx), and crabeater seals (Lobodon carcinophagus). Fossil seal samples were collected in the Dry Valleys during the austral summer of 2012/13 and then analyzed for bulk C and N isotopes via an elemental analyzer/isotope-ratio mass spectrometer (EA/IRMS). Our initial findings indicate that C isotopic values of fossil seal samples from Weddell, leopard, and crabeater seals were more enriched than isotopic values of modern seals of the same species (e.g., δ13C = -22.79 × 0.92 ‰ and -26.71 × 0.50 ‰ for fossil and modern crabeater seals, respectively). Given the relatively consistent diet of crabeater seals, these findings suggest a shift in baseline food web structure occurred over the last 10,000 years, either through changes in foraging location or local shifts in biogeochemistry. For all species, N isotopic values are widely variable (e.g., 7.28 to 16.0 δ15N ‰ for the Weddell seal), which may be a result of greatly changing diets in the last ~10,000 years, or a changing baseline N value for the Ross Sea. Seal bones will be radiocarbon-dated to isolate the key shifts in C and N isotopic values. Once those major shifts are temporally constrained, compound-specific isotopic analysis of the bone samples will be used to tease apart the diet vs. baseline effects on the bulk isotopic signatures of the seals. Our results suggests that during the last ~10,000 years, there was a fundamental shift in Ross Sea food web structure likely related to long term climatic variability.

Strong coupling of collection of emitters on hyperbolic meta-material

NASA Astrophysics Data System (ADS)

Biehs, Svend-Age; Xu, Chenran; Agarwal, Girish S.

2018-04-01

Recently, considerable effort has been devoted to the realization of a strong coupling regime of the radiation matter interaction in the context of an emitter at a meta surface. The strong interaction is well realized in cavity quantum electrodynamics, which also show that strong coupling is much easier to realize using a collection of emitters. Keeping this in mind, we study if emitters on a hyperbolic meta materials can yield a strong coupling regime. We show that strong coupling can be realized for densities of emitters exceeding a critical value. A way to detect strong coupling between emitters and hyperbolic metamaterials is to use the Kretschman-Raether configuration. The strong coupling appears as the splitting of the reflectivity dip. In the weak coupling regime, the dip position shifts. The shift and splitting can be used to sense active molecules at surfaces.

Determination of anisotropy constants of protein encapsulated iron oxide nanoparticles by electron magnetic resonance

NASA Astrophysics Data System (ADS)

Li, Hongyan; Klem, Michael T.; Sebby, Karl B.; Singel, David J.; Young, Mark; Douglas, Trevor; Idzerda, Yves U.

2009-02-01

Angle-dependent electron magnetic resonance was performed on 4.9, 8.0, and 19 nm iron oxide nanoparticles encapsulated within protein capsids and suspended in water. Measurements were taken at liquid nitrogen temperature after cooling in a 1 T field to partially align the particles. The angle dependence of the shifts in the resonance field for the iron oxide nanoparticles (synthesized within Listeria-Dps, horse spleen ferritin, and cowpea chlorotic mottle virus) all show evidence of a uniaxial anisotropy. Using a Boltzmann distribution for the particles' easy-axis direction, we are able to use the resonance field shifts to extract a value for the anisotropy energy, showing that the anisotropy energy density increases with decreasing particle size. This suggests that surface anisotropy plays a significant role in magnetic nanoparticles of this size.

Super RLuc8: A novel engineered Renilla luciferase with a red-shifted spectrum and stable light emission.

PubMed

Rahnama, Somaieh; Saffar, Behnaz; Kahrani, Zahra Fanaei; Nazari, Mahboobeh; Emamzadeh, Rahman

2017-01-01

Renilla luciferase is a bioluminescent enzyme which is broadly used as a reporter protein in molecular biosensors. In this study, a novel luciferase with desired light emission wavelength and thermostability is reported. The results indicated that the new luciferase, namely super RLuc8, had a red-shifted spectrum and showed stable light emission. Super RLuc8 showed a 10-fold (p-value=0.0084) increase in the thermostability at 37°C after 20min incubation, in comparison to the native enzyme. The optimum temperature of the mutant increased from 30 to 37°C. Molecular dynamics simulation analysis indicated that the increased thermostability was most probably caused by a better structural compactness and more local rigidity in the regions out of the emitter site. Copyright © 2016 Elsevier Inc. All rights reserved.

SU-F-J-209: Quantification of Image-Guidance Benefit in Image-Guided Radiotherapy of Cancers

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

Zhou, L; Department of Therapeutic Radiology, Yale University, New Haven, CT; Deng, J

Purpose: Image-guidance has been widely used in radiation oncology for accurate radiotherapy. The goal of this study is to quantify the benefit of image-guidance in image-guided radiotherapy (IGRT) of cancers. Methods: In this study, a new index termed image-guidance benefit (IGB), was proposed to quantify the benefit of image-guidance in cancer radiotherapy. It is calculated as a ratio of the square sum of dose differences between planning dose matrix and actual delivery dose matrix post image-guidance to the square sum of dose summation between the two matrixes, summing over all dose scoring voxels. Ranging from 0 to 1, larger IGBmore » values indicate larger benefit out of image-guidance. With IRB approval, the DICOM RT files and 3D couch shifts applied during IGRT of 2219 patients were collected, based on which patient-specific IGB values were calculated with an in-house MATLAB code. Results: In this study, the mean IGB value was found to be 0.0398 (0.000583–0.999) with a positive correlation between IGB value and 3D couch shift vector at 0.0435 per cm (P<0.0001). With 2 mm shift as a threshold above which an image-guidance is deemed clinically necessary, the corresponding mean IGB value was 0.00457, much less than 0.0398 (P<0.001). However, the IGB values of 56 cases based on couch shifts were less than those based on 2 mm shift. Conclusion: The IGB values were patient-specific and site-dependent. Using 2 mm shifts as criterion for applying image-guidance, the applied image-guidance procedures were found clinically necessary and highly beneficial in 97.5% of cancer patients. However, image-guidance procedures were found over-used in about 2.5% of cancer patients in our current practices of IGRT, which should be avoided as they added no benefit in improving delivery accuracy while increasing cancer risk.« less

Benchmarking quantum mechanical calculations with experimental NMR chemical shifts of 2-HADNT

NASA Astrophysics Data System (ADS)

Liu, Yuemin; Junk, Thomas; Liu, Yucheng; Tzeng, Nianfeng; Perkins, Richard

2015-04-01

In this study, both GIAO-DFT and GIAO-MP2 calculations of nuclear magnetic resonance (NMR) spectra were benchmarked with experimental chemical shifts. The experimental chemical shifts were determined experimentally for carbon-13 (C-13) of seven carbon atoms for the TNT degradation product 2-hydroxylamino-4,6-dinitrotoluene (2-HADNT). Quantum mechanics GIAO calculations were implemented using Becke-3-Lee-Yang-Parr (B3LYP) and other six hybrid DFT methods (Becke-1-Lee-Yang-Parr (B1LYP), Becke-half-and-half-Lee-Yang-Parr (BH and HLYP), Cohen-Handy-3-Lee-Yang-Parr (O3LYP), Coulomb-attenuating-B3LYP (CAM-B3LYP), modified-Perdew-Wang-91-Lee-Yang-Parr (mPW1LYP), and Xu-3-Lee-Yang-Parr (X3LYP)) which use the same correlation functional LYP. Calculation results showed that the GIAO-MP2 method gives the most accurate chemical shift values, and O3LYP method provides the best prediction of chemical shifts among the B3LYP and other five DFT methods. Three types of atomic partial charges, Mulliken (MK), electrostatic potential (ESP), and natural bond orbital (NBO), were also calculated using MP2/aug-cc-pVDZ method. A reasonable correlation was discovered between NBO partial charges and experimental chemical shifts of carbon-13 (C-13).

Biological effect markers in exhaled breath condensate and biomonitoring in welders: impact of smoking and protection equipment.

PubMed

Gube, Monika; Ebel, Joachim; Brand, Peter; Göen, Thomas; Holzinger, Karl; Reisgen, Uwe; Kraus, Thomas

2010-10-01

The objective of this study was to investigate the effect of welding as well as the impact of smoking and protection measures on biological effect markers in exhaled breath condensate. Additionally, biomonitoring of chromium, aluminium and nickel in urine was performed to quantify internal exposure. Exhaled breath condensate (EBC) and urine samples of 45 male welders and 24 male non-exposed control subjects were collected on Friday pre-shift and after 8 h of work post-shift. In EBC, biological effect markers such as malondialdehyde, nitrite, nitrate, 3-nitrotyrosine, tyrosine, hydroxyproline, proline, H(2)O(2) and pH-value were measured while aluminium, nickel, and chromium were measured in the urine samples. Although internal exposure to aluminium, nickel and chromium in this study was low, welders showed significantly increased concentrations of all these parameters at baseline compared to non-exposed controls. Moreover, welders had higher nitrate concentrations in EBC at baseline and after shift. Nitrate concentration was considerably lower after shift if personal protection equipment was used. H(2)O(2) was increased only when subjects smoked during shift. It has been shown that welding-associated long-term and short-term health effects could be detected in a population of welders. The results also showed that using personal protection equipment is of high importance and H(2)O(2) may be an effect marker associated with smoking rather than with welding fumes, while nitrate in EBC seems to be sensitive to welding fume exposure.

Tip induced mechanical deformation of epitaxial graphene grown on reconstructed 6H-SiC(0001) surface during scanning tunneling and atomic force microscopy studies.

PubMed

Meza, José Antonio Morán; Lubin, Christophe; Thoyer, François; Cousty, Jacques

2015-01-26

The structural and mechanical properties of an epitaxial graphene (EG) monolayer thermally grown on top of a 6H-SiC(0001) surface were studied by combined dynamic scanning tunneling microscopy (STM) and frequency modulation atomic force microscopy (FM-AFM). Experimental STM, dynamic STM and AFM images of EG on 6H-SiC(0001) show a lattice with a 1.9 nm period corresponding to the (6 × 6) quasi-cell of the SiC surface. The corrugation amplitude of this (6 × 6) quasi-cell, measured from AFM topographies, increases with the setpoint value of the frequency shift Δf (15-20 Hz, repulsive interaction). Excitation variations map obtained simultaneously with the AFM topography shows that larger dissipation values are measured in between the topographical bumps of the (6 × 6) quasi-cell. These results demonstrate that the AFM tip deforms the graphene monolayer. During recording in dynamic STM mode, a frequency shift (Δf) map is obtained in which Δf values range from 41 to 47 Hz (repulsive interaction). As a result, we deduced that the STM tip, also, provokes local mechanical distortions of the graphene monolayer. The origin of these tip-induced distortions is discussed in terms of electronic and mechanical properties of EG on 6H-SiC(0001).

Within-trial contrast: pigeons prefer conditioned reinforcers that follow a relatively more rather than a less aversive event.

PubMed

Zentall, Thomas R; Singer, Rebecca A

2007-07-01

When behavior suggests that the value of a reinforcer depends inversely on the value of the events that precede or follow it, the behavior has been described as a contrast effect. Three major forms of contrast have been studied: incentive contrast, in which a downward (or upward) shift in the magnitude of reinforcement produces a relatively stronger downward (or upward) shift in the vigor of a response; anticipatory contrast, in which a forthcoming improvement in reinforcement results in a relative reduction in consummatory response; and behavioral contrast, in which a decrease in the probability of reinforcement in one component of a multiple schedule results in an increase in responding in an unchanged component of the schedule. Here we discuss a possible fourth kind of contrast that we call within-trial contrast because within a discrete trial, the relative value of an event has an inverse effect on the relative value of the reinforcer that follows. We show that greater effort, longer delay to reinforcement, or the absence of food all result in an increase in the preference for positive discriminative stimuli that follow (relative to less effort, shorter delay, or the presence of food). We further distinguish this within-trial contrast effect from the effects of delay reduction. A general model of this form of contrast is proposed in which the value of a primary or conditioned reinforcer depends on the change in value from the value of the event that precedes it.

Within-Trial Contrast: Pigeons Prefer Conditioned Reinforcers that Follow a Relatively More Rather than a Less Aversive Event

PubMed Central

Zentall, Thomas R; Singer, Rebecca A

2007-01-01

When behavior suggests that the value of a reinforcer depends inversely on the value of the events that precede or follow it, the behavior has been described as a contrast effect. Three major forms of contrast have been studied: incentive contrast, in which a downward (or upward) shift in the magnitude of reinforcement produces a relatively stronger downward (or upward) shift in the vigor of a response; anticipatory contrast, in which a forthcoming improvement in reinforcement results in a relative reduction in consummatory response; and behavioral contrast, in which a decrease in the probability of reinforcement in one component of a multiple schedule results in an increase in responding in an unchanged component of the schedule. Here we discuss a possible fourth kind of contrast that we call within-trial contrast because within a discrete trial, the relative value of an event has an inverse effect on the relative value of the reinforcer that follows. We show that greater effort, longer delay to reinforcement, or the absence of food all result in an increase in the preference for positive discriminative stimuli that follow (relative to less effort, shorter delay, or the presence of food). We further distinguish this within-trial contrast effect from the effects of delay reduction. A general model of this form of contrast is proposed in which the value of a primary or conditioned reinforcer depends on the change in value from the value of the event that precedes it. PMID:17725056

Are Categorical Spatial Relations Encoded by Shifting Visual Attention between Objects?

ERIC Educational Resources Information Center

Yuan, Lei; Uttal, David; Franconeri, Steven

2016-01-01

Perceiving not just values, but relations between values, is critical to human cognition. We tested the predictions of a proposed mechanism for processing categorical spatial relations between two objects--the "shift account" of relation processing--which states that relations such as "above" or "below" are extracted…

¹H-MAS-NMR chemical shifts in hydrogen-bonded complexes of chlorophenols (pentachlorophenol, 2,4,6-trichlorophenol, 2,6-dichlorophenol, 3,5-dichlorophenol, and p-chlorophenol) and amine, and H/D isotope effects on ¹H-MAS-NMR spectra.

PubMed

Honda, Hisashi

2013-04-22

Chemical shifts (CS) of the ¹H nucleus in N···H···O type hydrogen bonds (H-bond) were observed in some complexes between chlorophenols [pentachlorophenol (PCP), 2,4,6-tricholorophenol (TCP), 2,6-dichlorophenol (26DCP), 3,5-dichlorophenol (35DCP), and p-chlorophenol (pCP)] and nitrogen-base (N-Base) by solid-state high-resolution ¹H-NMR with the magic-angle-spinning (MAS) method. Employing N-Bases with a wide range of pKa values (0.65-10.75), ¹H-MAS-NMR CS values of bridging H atoms in H-bonds were obtained as a function of the N-Base's pKa. The result showed that the CS values were increased with increasing pKa values in a range of DpKa < 0 [DpKa = pKa(N-Base)-pKa(chlorophenols)] and decreased when DpKa > 2: The maximum CS values was recorded in the PCP (pKa = 5.26)-4-methylpyridine (6.03), TCP (6.59)-imidazole (6.99), 26DCP (7.02)-2-amino-4-methylpyridine (7.38), 35DCP (8.04)-4-dimethylaminopyridine (9.61), and pCP (9.47)-4-dimethylaminopyridine (9.61) complexes. The largest CS value of 18.6 ppm was recorded in TCP-imidazole crystals. In addition, H/D isotope effects on ¹H-MAS-NMR spectra were observed in PCP-2-amino-3-methylpyridine. Based on the results of CS simulation using a B3LYP/6-311+G** function, it can be explained that a little changes of the N-H length in H-bond contribute to the H/D isotope shift of the ¹H-MAS-NMR peaks.

Nanoscale mass detection based on vibrating piezoelectric ultrathin films under thermo-electro-mechanical loads

NASA Astrophysics Data System (ADS)

Asemi, H. R.; Asemi, S. R.; Farajpour, A.; Mohammadi, M.

2015-04-01

The potential applications of piezoelectric nanofilms (PNFs) and double-piezoelectric-nanofilm (DPNF) systems as nanoelectromechanical mass sensors are examined. The PNFs carrying multiple nanoparticles at arbitrary locations are modeled as rectangular nonlocal plates with attached concentrated masses. Using the nonlocal elasticity theory and Hamilton's principle, the differential equations of motion are derived for both PNF-based and DPNF-based nanosensors. The influences of small scale, initial stress and temperature change on the frequency shifts of the nanoelectromechanical sensors are taken into consideration. Explicit expressions are derived for the resonance frequencies of the nanosensors by employing the Galerkin method. The present results show that when the value of nonlocal parameter decreases, the frequency shifts of piezoelectric nanosensors increase. Further, the frequency shifts of DPNF-based mass sensors are always greater than those of PNF-based mass sensors. The present work would be helpful in the design of nanoelectromechanical mass sensors using PNFs.

Universal Faraday Rotation in HgTe Wells with Critical Thickness.

PubMed

Shuvaev, A; Dziom, V; Kvon, Z D; Mikhailov, N N; Pimenov, A

2016-09-09

The universal value of the Faraday rotation angle close to the fine structure constant (α≈1/137) is experimentally observed in thin HgTe quantum wells with a thickness on the border between trivial insulating and the topologically nontrivial Dirac phases. The quantized value of the Faraday angle remains robust in the broad range of magnetic fields and gate voltages. Dynamic Hall conductivity of the holelike carriers extracted from the analysis of the transmission data shows a theoretically predicted universal value of σ_{xy}=e^{2}/h, which is consistent with the doubly degenerate Dirac state. On shifting the Fermi level by the gate voltage, the effective sign of the charge carriers changes from positive (holes) to negative (electrons). The electronlike part of the dynamic response does not show quantum plateaus and is well described within the classical Drude model.

Modelling growth of Penicillium expansum and Aspergillus niger at constant and fluctuating temperature conditions.

PubMed

Gougouli, Maria; Koutsoumanis, Konstantinos P

2010-06-15

The growth of Penicillium expansum and Aspergillus niger, isolated from yogurt production environment, was investigated on malt extract agar with pH=4.2 and a(w)=0.997, simulating yogurt, at isothermal conditions ranging from -1.3 to 35 degrees C and from 5 to 42.3 degrees C, respectively. The growth rate (mu) and (apparent) lag time (lambda) of the mycelium growth were modelled as a function of temperature using a Cardinal Model with Inflection (CMI). The results showed that the CMI can describe successfully the effect of temperature on fungal growth within the entire biokinetic range for both isolates. The estimated values of the CMI for mu were T(min)=-5.74 degrees C, T(max)=30.97 degrees C, T(opt)=22.08 degrees C and mu(opt)=0.221 mm/h for P. expansum and T(min)=10.13 degrees C, T(max)=43.13 degrees C, T(opt)=31.44 degrees C, and mu(opt)=0.840 mm/h for A. niger. The cardinal values for lambda were very close to the respective values for mu indicating similar temperature dependence of the growth rate and the lag time of the mycelium growth. The developed models were further validated under fluctuating temperature conditions using various dynamic temperature scenarios. The time-temperature conditions studied included single temperature shifts before or after the end of the lag time and continuous periodic temperature fluctuations. The prediction of growth at changing temperature was based on the assumption that after a temperature shift the growth rate is adopted instantaneously to the new temperature, while the lag time was predicted using a cumulative lag approach. The results showed that when the temperature shifts occurred before the end of the lag, they did not cause any significant additional lag and the observed total lag was very close to the cumulative lag predicted by the model. In experiments with temperature shifts after the end of the lag time, accurate predictions were obtained when the temperature profile included temperatures which were inside the region of growth, showing that the assumption that mu is adopted instantaneously to the current temperature is concrete. In contrast, for scenarios with temperatures close or outside the growth region the models overestimated growth, indicating that fungi were stressed by this type of temperature shifts. The present study provides useful data for understanding the behavior of P. expansum and A. niger at dynamic temperature conditions while the developed models can be used as effective tools in assessing the risk of fungal spoilage and predicting shelf life of foods. Copyright 2010. Published by Elsevier B.V.

13C and (15)N chemical shift tensors in adenosine, guanosine dihydrate, 2'-deoxythymidine, and cytidine.

PubMed

Stueber, Dirk; Grant, David M

2002-09-04

The (13)C and (15)N chemical shift tensor principal values for adenosine, guanosine dihydrate, 2'-deoxythymidine, and cytidine are measured on natural abundance samples. Additionally, the (13)C and (15)N chemical shielding tensor principal values in these four nucleosides are calculated utilizing various theoretical approaches. Embedded ion method (EIM) calculations improve significantly the precision with which the experimental principal values are reproduced over calculations on the corresponding isolated molecules with proton-optimized geometries. The (13)C and (15)N chemical shift tensor orientations are reliably assigned in the molecular frames of the nucleosides based upon chemical shielding tensor calculations employing the EIM. The differences between principal values obtained in EIM calculations and in calculations on isolated molecules with proton positions optimized inside a point charge array are used to estimate the contributions to chemical shielding arising from intermolecular interactions. Moreover, the (13)C and (15)N chemical shift tensor orientations and principal values correlate with the molecular structure and the crystallographic environment for the nucleosides and agree with data obtained previously for related compounds. The effects of variations in certain EIM parameters on the accuracy of the shielding tensor calculations are investigated.

Nano-scale mass sensor based on the vibration analysis of a magneto-electro-elastic nanoplate resting on a visco-Pasternak substrate

NASA Astrophysics Data System (ADS)

Khanmirza, E.; Jamalpoor, A.; Kiani, A.

2017-10-01

In this paper, a magneto-electro-elastic nanoplate resting on a visco-Pasternak medium with added concentrated nanoparticles is presented as a mass nanosensor according to the vibration analysis. The MEE nanoplate is supposed to be subject to external electric voltage and magnetic potential. In order to take into account the size effect on the sensitivity of the sensor, the nonlocal elasticity theory in conjunction with the Kirchhoff plate theory is applied. Partial differential equations are derived by implementing Hamilton's variational principle. Equilibrium equations were solved analytically to determine an explicit closed-form statement for both the damped frequency shift and the relative damped frequency shift using Navier's approach. A genetic algorithm (GA) is employed to achieve the optimal added nanoparticle location to gain the most sensitivity performance of the nanosensor. Numerical studies are performed to illustrate the variation of the sensitivity property corresponding to various values of the number of attached nanoparticles, the mass of each nanoparticle, the nonlocal parameter, external electric voltage and magnetic potential, the aspect ratio, and visco-Pasternak parameters. Some numerical outcomes of this paper show that the minimum value of the damped frequency shift occurs for a certain value of the length-to-thickness ratio. Also, it is shown that the external magnetic and external electric potentials have a different effect on the sensitivity property. It is anticipated that the results reported in this work can be considered as a benchmark in future micro-structures issues.

The influence of applied internal and external rotation on the pivot shift phenomenon.

PubMed

Kopf, Sebastian; Musahl, Volker; Perka, Carsten; Kauert, Ralf; Hoburg, Arnd; Becker, Roland

2017-04-01

The pivot shift test is performed in different techniques and the rotation of the tibia seems to have a significant impact on the amount of the pivot shift phenomenon. It has been hypothesised that external rotation will increase the phenomenon due to less tension at the iliotibial band in knee extension. Twenty-four patients with unilateral anterior cruciate ligament insufficiency were included prospectively. The pivot shift test was performed bilaterally in internal and external tibial rotation under general anaesthesia. Knee motion was captured using a femoral and a tibial inertial sensor. The difference between positive and negative peak values in Euclidean norm of acceleration was calculated to evaluate the amount of the pivot shift phenomenon. The pivot shift phenomenon was significantly increased in patients with ACL insufficiency when the test was performed in external [mean 5.2 ms - 2 (95% CI 4.3-6.0)] compared to internal tibial rotation [mean 4.4 ms - 2 (95% CI 3.5-5.4)] (p = 0.002). In healthy, contralateral knees did not show any difference between external [mean 4.0 ms - 2 (95% CI 3.3-4.7)] and internal tibial rotation [mean 4.0 ms - 2 (95% CI 3.4-4.6)] (ns). The pivot shift phenomenon was increased with external rotation in ACL-insufficient knees, and therefore, one should perform the pivot shift test, rather, in external rotation to easily evoke the, sometimes difficult to detect, pivot shift phenomenon. I (diagnostic study).

Unexpectedly large difference of the electron density at the nucleus in the 4p ^2{P}_{{1}/{2},{3}/{2}} fine-structure doublet of Ca^+

NASA Astrophysics Data System (ADS)

Shi, C.; Gebert, F.; Gorges, C.; Kaufmann, S.; Nörtershäuser, W.; Sahoo, B. K.; Surzhykov, A.; Yerokhin, V. A.; Berengut, J. C.; Wolf, F.; Heip, J. C.; Schmidt, P. O.

2017-01-01

We measured the isotope shift in the ^2{S}_{{1}/{2}} → ^2{P}_{{3}/{2}} (D2) transition in singly ionized calcium ions using photon recoil spectroscopy. The high accuracy of the technique enables us to compare the difference between the isotope shifts of this transition to the previously measured isotopic shifts of the ^2{S}_{{1}/{2}} → ^2{P}_{{1}/{2}} (D1) line. This so-called splitting isotope shift is extracted and exhibits a clear signature of field shift contributions. From the data, we were able to extract the small difference of the field shift coefficient and mass shifts between the two transitions with high accuracy. This J-dependence is of relativistic origin and can be used to benchmark atomic structure calculations. As a first step, we use several ab initio atomic structure calculation methods to provide more accurate values for the field shift constants and their ratio. Remarkably, the high-accuracy value for the ratio of the field shift constants extracted from the experimental data is larger than all available theoretical predictions.

Host Plant Physiology and Mycorrhizal Functioning Shift across a Glacial through Future [CO2] Gradient1[OPEN

PubMed Central

Mullinix, George W.R.; Ward, Joy K.

2016-01-01

Rising atmospheric carbon dioxide concentration ([CO2]) may modulate the functioning of mycorrhizal associations by altering the relative degree of nutrient and carbohydrate limitations in plants. To test this, we grew Taraxacum ceratophorum and Taraxacum officinale (native and exotic dandelions) with and without mycorrhizal fungi across a broad [CO2] gradient (180–1,000 µL L−1). Differential plant growth rates and vegetative plasticity were hypothesized to drive species-specific responses to [CO2] and arbuscular mycorrhizal fungi. To evaluate [CO2] effects on mycorrhizal functioning, we calculated response ratios based on the relative biomass of mycorrhizal (MBio) and nonmycorrhizal (NMBio) plants (RBio = [MBio − NMBio]/NMBio). We then assessed linkages between RBio and host physiology, fungal growth, and biomass allocation using structural equation modeling. For T. officinale, RBio increased with rising [CO2], shifting from negative to positive values at 700 µL L−1. [CO2] and mycorrhizal effects on photosynthesis and leaf growth rates drove shifts in RBio in this species. For T. ceratophorum, RBio increased from 180 to 390 µL L−1 and further increases in [CO2] caused RBio to shift from positive to negative values. [CO2] and fungal effects on plant growth and carbon sink strength were correlated with shifts in RBio in this species. Overall, we show that rising [CO2] significantly altered the functioning of mycorrhizal associations. These symbioses became more beneficial with rising [CO2], but nonlinear effects may limit plant responses to mycorrhizal fungi under future [CO2]. The magnitude and mechanisms driving mycorrhizal-CO2 responses reflected species-specific differences in growth rate and vegetative plasticity, indicating that these traits may provide a framework for predicting mycorrhizal responses to global change. PMID:27573369

The Value of Concentrating Solar Power and Thermal Energy Storage

DOE PAGES

Sioshansi, Ramteen; Denholm, Paul

2010-06-14

Our paper examines the value of concentrating solar power (CSP) and thermal energy storage (TES) in a number of regions in the southwestern United States. Our analysis also shows that TES can increase the value of CSP by allowing more thermal energy from a CSP plant's solar field to be used, allowing a CSP plant to accommodate a larger solar field, and by allowing CSP generation to be shifted to hours with higher energy prices. We also analyze the sensitivity of this value to a number of factors, including the optimization period, price and solar forecasting, ancillary service sales, andmore » dry cooling of the CSP plant, and also estimate the capacity value of a CSP plant with TES. We further discuss the value of CSP plants and TES net of capital costs.« less

Effects on skylight at South Pole Station, Antarctica, by ice crystal precipitation in the atmosphere

NASA Technical Reports Server (NTRS)

Fitch, B. W.; Coulson, K. L.

1983-01-01

Measurements of the radiance and polarization of the skylight at South Pole Station, Antarctica, were made for clear cloud-free skies and cloudless skies with ice crystal precipitation. The measurements were made at six narrowband wavelengths from 321 to 872 nm in the principal plane. The data show that scattering by ice crystals increases the radiance in the backscatter plane, decreases it in the solar plane, and shifts the radiance minimum to a point closer to the sun. The crystals decrease the maximum value of linear polarization and shift the position of the maximum away from the sun. The influence of ice crystal scattering is greatest at the longer wavelengths.

Effects on skylight at South Pole Station, Antarctica, by ice crystal precipitation in the atmosphere.

PubMed

Fitch, B W; Coulson, K L

1983-01-01

Measurements of the radiance and polarization of the skylight at South Pole Station, Antarctica, were made for clear cloud-free skies and cloudless skies with ice crystal precipitation. The measurements were made at six narrowband wavelengths from 321 to 872 nm in the principal plane. The data show that scattering by ice crystals increases the radiance in the backscatter plane, decreases it in the solar plane, and shifts the radiance minimum to a point closer to the sun. The crystals decrease the maximum value of linear polarization and shift the position of the maximum away from the sun. The influence of ice crystal scattering is greatest at the longer wavelengths.

Composition, structure, and properties of iron-rich nontronites of different origins

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

Palchik, N. A., E-mail: nadezhda@igm.nsc.ru; Grigorieva, T. N.; Moroz, T. N.

2013-03-15

The composition, structure, and properties of smectites of different origins have been studied by X-ray diffraction, IR spectroscopy, scanning electron microscopy, and microprobe analysis. The results showed that nontronites of different origins differ in composition, properties, morphology, and IR spectroscopic characteristics. Depending on the degree of structural order and the negative charge of iron-silicate layers in nontronites, the shift of the 001 reflection to smaller angles as a result of impregnation with ethylene glycol (this shift is characteristic of the smectite group) occurs differently. The calculated values of the parameter b (from 9.11 to 9.14A) are valid for the extrememore » terms of dioctahedral smectite representatives: nontronites.« less

A risk hedging strategy under the nonparallel-shift yield curve

NASA Astrophysics Data System (ADS)

Gong, Pu; He, Xubiao

2005-08-01

Under the assumption of the movement of rigid, a nonparallel-shift model in the term structure of interest rates is developed by introducing Fisher & Weil duration which is a well-known concept in the area of interest risk management. This paper has studied the hedge and replication for portfolio immunization to minimize the risk exposure. Throughout the experiment of numerical simulation, the risk exposures of the portfolio under the different risk hedging strategies are quantitatively evaluated by the method of value at risk (VaR) order statistics (OS) estimation. The results show that the risk hedging strategy proposed in this paper is very effective for the interest risk management of the default-free bond.

Oxygen-isotope trends and seawater temperature changes across the Late Cambrian Steptoean positive carbon-isotope excursion (SPICE event)

USGS Publications Warehouse

Elrick, M.; Rieboldt, S.; Saltzman, M.; McKay, R.M.

2011-01-01

The globally recognized Late Cambrian Steptoean positive C-isotope excursion (SPICE) is characterized by a 3???-5??? positive ??13C shift spanning <4 m.y. Existing hypotheses suggest that the SPICE represents a widespread ocean anoxic event leading to enhanced burial/preservation of organic matter (Corg) and pyrite. We analyzed ??18O values of apatitic inarticulate brachiopods from three Upper Cambrian successions across Laurentia to evaluate paleotemperatures during the SPICE. ??18O values range from ~12.5??? to 16.5???. Estimated seawater temperatures associated with the SPICE are unreasonably warm, suggesting that the brachiopod ??18O values were altered during early diagenesis. Despite this, all three localities show similar trends with respect to the SPICE ??13C curve, suggesting that the brachiopod apatite preserves a record of relative ??18O and temperature changes. The trends include relatively high ??18O values at the onset of the SPICE, decreasing and lowest values during the main event, and an increase in values at the end of the event. The higher ??18O values during the global extinction at the onset of the SPICE suggests seawater cooling and supports earlier hypotheses of upwelling of cool waters onto the shallow shelf. Decreasing and low ??18O values coincident with the rising limb of the SPICE support the hypothesis that seawater warming and associated reduced thermohaline circulation rates contributed to decreased dissolved O2 concentrations, which enhanced the preservation/burial of Corg causing the positive ??13C shift. ?? 2011 Geological Society of America.

Noise level in a neonatal intensive care unit in Santa Marta - Colombia.

PubMed

Garrido Galindo, Angélica Patricia; Camargo Caicedo, Yiniva; Velez-Pereira, Andres M

2017-09-30

The environment of neonatal intensive care units is influenced by numerous sources of noise emission, which contribute to raise the noise levels, and may cause hearing impairment and other physiological and psychological changes on the newborn, as well as problems with care staff. To evaluate the level and sources of noise in the neonatal intensive care unit. Sampled for 20 consecutive days every 60 seconds in A-weighting curves and fast mode with a Type I sound level meter. Recorded the average, maximum and minimum, and the 10th, 50th and 90th percentiles. The values are integrated into hours and work shift, and studied by analysis of variance. The sources were characterized in thirds of octaves. The average level was 64.00 ±3.62 dB(A), with maximum of 76.04 ±5.73 dB(A), minimum of 54.84 ±2.61dB(A), and background noise of 57.95 ±2.83 dB(A). We found four sources with levels between 16.8-63.3 dB(A). Statistical analysis showed significant differences between the hours and work shift, with higher values in the early hours of the day. The values presented exceed the standards suggested by several organizations. The sources identified and measured recorded high values in low frequencies.

NOLM-based all-optical 40 Gbit/s format conversion through sum-frequency generation (SFG) in a PPLN waveguide

NASA Astrophysics Data System (ADS)

Wang, Jian; Sun, Junqiang

2005-11-01

A novel all-optical format conversion scheme from NRZ to RZ based on sum-frequency generation (SFG) in a periodically poled LiNbO 3 (PPLN) waveguide is proposed, using a nonlinear optical loop mirror (NOLM). The conversion mechanism relies on the combination of attenuation and nonlinear phase shift induced on the clockwise signal field during the SFG process. The SFG between pump, and co- and counter- propagating signals in the PPLN waveguide are numerically studied, showing that counter-propagating SFG can be ignored when quasi-phase matching (QPM) for SFG during co-propagating interaction. The nonlinear phase shift induced on the clockwise signal field is analyzed in detail, showing that it is more effective to yield large values for nonlinear phase shift when appropriately phase mismatched for the SFG process. Two tuning schemes are proposed depend on whether the sum-frequency wavelength is variable or fixed. It is found that the latter has a rather wide 3dB signal conversion bandwidth approximately 154nm. Finally, the influence of reversible process of SFG is discussed and the optimum arrangement of pump and signal peak powers is theoretically demonstrated. The result shows that proper power arrangement, pump width, and waveguide length are necessary for achieving a good conversion effect.

Talking Trade: Literacy Researchers as Practicing Artists

ERIC Educational Resources Information Center

Albers, Peggy; Holbrook, Teri; Harste, Jerome C.

2010-01-01

Over the past two decades, educational scholars have seen major shifts in how literacy is viewed. One of these shifts has been toward conceptualizing literacy as a set of social practices (Street, 1995) that people embody and value. To disrupt current definitions of literacy, the valued practices that keep those forms of literacy in place must…

A solvent-isotope-effect study of proton transfer during catalysis by Escherichia coli (lacZ) beta-galactosidase.

PubMed Central

Selwood, T; Sinnott, M L

1990-01-01

1. Michaelis-Menten parameters for the hydrolysis of 4-nitrophenyl beta-D-galactopyranoside and 3,4-dinitrophenyl beta-D-galactopyranoside Escherichia coli (lacZ) beta-galactosidase were measured as a function of pH or pD (pL) in both 1H2O and 2H2O. 2. For hydrolysis of 4-nitrophenyl beta-D-galactopyranoside by Mg2(+)-free enzyme, V is pL-independent below pL 9, but the V/Km-pL profile is sigmoid, the pK values shifting from 7.6 +/- 0.1 in 1H2O to 8.2 +/- 0.1 in 2H2O, and solvent kinetic isotope effects are negligible, in accord with the proposal [Sinnott, Withers & Viratelle (1978) Biochem. J. 175, 539-546] that glycone-aglycone fission without acid catalysis governs both V and V/Km. 3. V for hydrolysis of 4-nitrophenyl beta-D-galactopyranoside by Mg2(+)-enzyme varies sigmoidally with pL, the pK value shifting from 9.19 +/- 0.09 to 9.70 +/- 0.07; V/Km shows both a low-pL fall, probably due to competition between Mg2+ and protons [Tenu, Viratelle, Garnier & Yon (1971) Eur. J. Biochem. 20, 363-370], and a high-pL fall, governed by a pK that shifts from 8.33 +/- 0.08 to 8.83 +/- 0.08. There is a negligible solvent kinetic isotope effect on V/Km, but one of 1.7 on V, which a linear proton inventory shows to arise from one transferred proton. 4. The variation of V and V/Km with pL is sigmoid for hydrolysis of 3,4-dinitrophenyl beta-D-galactopyranoside by Mg2(+)-enzyme, with pK values showing small shifts, from 8.78 +/- 0.09 to 8.65 +/- 0.08 and from 8.7 +/- 0.1 to 8.9 +/- 0.1 respectively. There is no solvent isotope effect on V or V/Km for 3,4-dinitrophenyl beta-D-galactopyranoside, despite hydrolysis of the galactosyl-enzyme intermediate governing V. 5. Identification of the 'conformation change' in the hydrolysis of aryl galactosides proposed by Sinnott & Souchard [(1973) Biochem. J. 133, 89-98] with the protolysis of the magnesium phenoxide arising from the action of enzyme-bound Mg2+ as an electrophilic catalyst rationalizes these data and also resolves the conflict between the proposals and the 18O kinetic-isotope-effect data reported by Rosenberg & Kirsch [(1981) Biochemistry 20, 3189-3196]. It should be noted that the actual Km values were determined to higher precision than can be estimated from the Figures in this paper.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:2114090

A solvent-isotope-effect study of proton transfer during catalysis by Escherichia coli (lacZ) beta-galactosidase.

PubMed

Selwood, T; Sinnott, M L

1990-06-01

1. Michaelis-Menten parameters for the hydrolysis of 4-nitrophenyl beta-D-galactopyranoside and 3,4-dinitrophenyl beta-D-galactopyranoside Escherichia coli (lacZ) beta-galactosidase were measured as a function of pH or pD (pL) in both 1H2O and 2H2O. 2. For hydrolysis of 4-nitrophenyl beta-D-galactopyranoside by Mg2(+)-free enzyme, V is pL-independent below pL 9, but the V/Km-pL profile is sigmoid, the pK values shifting from 7.6 +/- 0.1 in 1H2O to 8.2 +/- 0.1 in 2H2O, and solvent kinetic isotope effects are negligible, in accord with the proposal [Sinnott, Withers & Viratelle (1978) Biochem. J. 175, 539-546] that glycone-aglycone fission without acid catalysis governs both V and V/Km. 3. V for hydrolysis of 4-nitrophenyl beta-D-galactopyranoside by Mg2(+)-enzyme varies sigmoidally with pL, the pK value shifting from 9.19 +/- 0.09 to 9.70 +/- 0.07; V/Km shows both a low-pL fall, probably due to competition between Mg2+ and protons [Tenu, Viratelle, Garnier & Yon (1971) Eur. J. Biochem. 20, 363-370], and a high-pL fall, governed by a pK that shifts from 8.33 +/- 0.08 to 8.83 +/- 0.08. There is a negligible solvent kinetic isotope effect on V/Km, but one of 1.7 on V, which a linear proton inventory shows to arise from one transferred proton. 4. The variation of V and V/Km with pL is sigmoid for hydrolysis of 3,4-dinitrophenyl beta-D-galactopyranoside by Mg2(+)-enzyme, with pK values showing small shifts, from 8.78 +/- 0.09 to 8.65 +/- 0.08 and from 8.7 +/- 0.1 to 8.9 +/- 0.1 respectively. There is no solvent isotope effect on V or V/Km for 3,4-dinitrophenyl beta-D-galactopyranoside, despite hydrolysis of the galactosyl-enzyme intermediate governing V. 5. Identification of the 'conformation change' in the hydrolysis of aryl galactosides proposed by Sinnott & Souchard [(1973) Biochem. J. 133, 89-98] with the protolysis of the magnesium phenoxide arising from the action of enzyme-bound Mg2+ as an electrophilic catalyst rationalizes these data and also resolves the conflict between the proposals and the 18O kinetic-isotope-effect data reported by Rosenberg & Kirsch [(1981) Biochemistry 20, 3189-3196]. It should be noted that the actual Km values were determined to higher precision than can be estimated from the Figures in this paper.(ABSTRACT TRUNCATED AT 400 WORDS)

Ecosystem shifts under climate change - a multi-model analysis from ISI-MIP

NASA Astrophysics Data System (ADS)

Warszawski, Lila; Beerling, David; Clark, Douglas; Friend, Andrew; Ito, Akihito; Kahana, Ron; Keribin, Rozenn; Kleidon, Axel; Lomas, Mark; Lucht, Wolfgang; Nishina, Kazuya; Ostberg, Sebastian; Pavlick, Ryan; Tito Rademacher, Tim; Schaphoff, Sibyll

2013-04-01

Dramatic ecosystem shifts, relating to vegetation composition and water and carbon stocks and fluxes, are potential consequences of climate change in the twenty-first century. Shifting climatic conditions, resulting in changes in biogeochemical properties of the ecosystem, will render it difficult for endemic plant and animal species to continue to survive in their current habitat. The potential for major shifts in biomes globally will also have severe consequences for the humans who rely on vital ecosystem services. Here we employ a novel metric of ecosystem shift to quantify the magnitude and uncertainty in these shifts at different levels of global warming, based on the response of seven biogeochemical Earth models to different future climate scenarios, in the context of the Intersectoral Impact Model Intercomparison Project (ISI-MIP). Based on this ensemble, 15% of the Earth's land surface will experience severe ecosystem shifts at 2°C degrees of global warming above 1980-2010 levels. This figure rises monotonically with global mean temperature for all models included in this study, reaching a median value of 60% of the land surface in a 4°C warmer world. At both 2°C and 4°C of warming, the most pronounced shifts occur in south-eastern India and south-western China, large swathes of the northern lattitudes above 60°N, the Amazon region and sub-Saharan Africa. Where dynamic vegetation composition is modelled, these shifts correspond to significant reductions in the land surface of vunerable vegetation types. We show that global mean temperature is a robust predictor of ecosystem shifts, whilst the spread across impact models is the greatest contributor to uncertainty.

Singular-value demodulation of phase-shifted holograms.

PubMed

Lopes, Fernando; Atlan, Michael

2015-06-01

We report on phase-shifted holographic interferogram demodulation by singular-value decomposition. Numerical processing of optically acquired interferograms over several modulation periods was performed in two steps: (1) rendering of off-axis complex-valued holograms by Fresnel transformation of the interferograms; and (2) eigenvalue spectrum assessment of the lag-covariance matrix of hologram pixels. Experimental results in low-light recording conditions were compared with demodulation by Fourier analysis, in the presence of random phase drifts.

Methodology to reduce 6D patient positional shifts into a 3D linear shift and its verification in frameless stereotactic radiotherapy

NASA Astrophysics Data System (ADS)

Sarkar, Biplab; Ray, Jyotirmoy; Ganesh, Tharmarnadar; Manikandan, Arjunan; Munshi, Anusheel; Rathinamuthu, Sasikumar; Kaur, Harpreet; Anbazhagan, Satheeshkumar; Giri, Upendra K.; Roy, Soumya; Jassal, Kanan; Kalyan Mohanti, Bidhu

2018-04-01

The aim of this article is to derive and verify a mathematical formulation for the reduction of the six-dimensional (6D) positional inaccuracies of patients (lateral, longitudinal, vertical, pitch, roll and yaw) to three-dimensional (3D) linear shifts. The formulation was mathematically and experimentally tested and verified for 169 stereotactic radiotherapy patients. The mathematical verification involves the comparison of any (one) of the calculated rotational coordinates with the corresponding value from the 6D shifts obtained by cone beam computed tomography (CBCT). The experimental verification involves three sets of measurements using an ArcCHECK phantom, when (i) the phantom was not moved (neutral position: 0MES), (ii) the position of the phantom shifted by 6D shifts obtained from CBCT (6DMES) from neutral position and (iii) the phantom shifted from its neutral position by 3D shifts reduced from 6D shifts (3DMES). Dose volume histogram and statistical comparisons were made between ≤ft< TPSCAL{\\text -}0MES \\right> and ≤ft< 3DMES{\\text -6DMES} \\right> . The mathematical verification was performed by a comparison of the calculated and measured yaw (γ°) rotation values, which gave a straight line, Y  =  1X with a goodness of fit as R 2  =  0.9982. The verification, based on measurements, gave a planning target volume receiving 100% of the dose (V100%) as 99.1  ±  1.9%, 96.3  ±  1.8%, 74.3  ±  1.9% and 72.6  ±  2.8% for the calculated treatment planning system values TPSCAL, 0MES, 3DMES and 6DMES, respectively. The statistical significance (p-values: paired sample t-test) of V100% were found to be 0.03 for the paired sample ≤ft< 3DMES{\\text -6DMES} \\right> and 0.01 for ≤ft< 0MES{\\text -TPSCAL} \\right> . In this paper, a mathematical method to reduce 6D shifts to 3D shifts is presented. The mathematical method is verified by using well-matched values between the measured and calculated γ°. Measurements done on the ArcCHECK phantom also proved that the proposed methodology is correct. The post-correction of the table position condition introduces a minimal spatial dose delivery error in the frameless stereotactic system, using a 6D motion enabled robotic couch. This formulation enables the reduction of 6D positional inaccuracies to 3D linear shifts, and hence allows the treatment of patients with frameless stereotactic radiosurgery by using only a 3D linear motion enabled couch.

Methodology to reduce 6D patient positional shifts into a 3D linear shift and its verification in frameless stereotactic radiotherapy.

PubMed

Sarkar, Biplab; Ray, Jyotirmoy; Ganesh, Tharmarnadar; Manikandan, Arjunan; Munshi, Anusheel; Rathinamuthu, Sasikumar; Kaur, Harpreet; Anbazhagan, Satheeshkumar; Giri, Upendra K; Roy, Soumya; Jassal, Kanan; Mohanti, Bidhu Kalyan

2018-03-22

The aim of this article is to derive and verify a mathematical formulation for the reduction of the six-dimensional (6D) positional inaccuracies of patients (lateral, longitudinal, vertical, pitch, roll and yaw) to three-dimensional (3D) linear shifts. The formulation was mathematically and experimentally tested and verified for 169 stereotactic radiotherapy patients. The mathematical verification involves the comparison of any (one) of the calculated rotational coordinates with the corresponding value from the 6D shifts obtained by cone beam computed tomography (CBCT). The experimental verification involves three sets of measurements using an ArcCHECK phantom, when (i) the phantom was not moved (neutral position: 0MES), (ii) the position of the phantom shifted by 6D shifts obtained from CBCT (6DMES) from neutral position and (iii) the phantom shifted from its neutral position by 3D shifts reduced from 6D shifts (3DMES). Dose volume histogram and statistical comparisons were made between [Formula: see text] and [Formula: see text]. The mathematical verification was performed by a comparison of the calculated and measured yaw (γ°) rotation values, which gave a straight line, Y  =  1X with a goodness of fit as R 2   =  0.9982. The verification, based on measurements, gave a planning target volume receiving 100% of the dose (V100%) as 99.1  ±  1.9%, 96.3  ±  1.8%, 74.3  ±  1.9% and 72.6  ±  2.8% for the calculated treatment planning system values TPSCAL, 0MES, 3DMES and 6DMES, respectively. The statistical significance (p-values: paired sample t-test) of V100% were found to be 0.03 for the paired sample [Formula: see text] and 0.01 for [Formula: see text]. In this paper, a mathematical method to reduce 6D shifts to 3D shifts is presented. The mathematical method is verified by using well-matched values between the measured and calculated γ°. Measurements done on the ArcCHECK phantom also proved that the proposed methodology is correct. The post-correction of the table position condition introduces a minimal spatial dose delivery error in the frameless stereotactic system, using a 6D motion enabled robotic couch. This formulation enables the reduction of 6D positional inaccuracies to 3D linear shifts, and hence allows the treatment of patients with frameless stereotactic radiosurgery by using only a 3D linear motion enabled couch.

Measurement of 13C chemical shift tensor principal values with a magic-angle turning experiment.

PubMed

Hu, J Z; Orendt, A M; Alderman, D W; Pugmire, R J; Ye, C; Grant, D M

1994-08-01

The magic-angle turning (MAT) experiment introduced by Gan is developed into a powerful and routine method for measuring the principal values of 13C chemical shift tensors in powdered solids. A large-volume MAT probe with stable rotation frequencies down to 22 Hz is described. A triple-echo MAT pulse sequence is introduced to improve the quality of the two-dimensional baseplane. It is shown that measurements of the principal values of chemical shift tensors in complex compounds can be enhanced by using either short contact times or dipolar dephasing pulse sequences to isolate the powder patterns from protonated or non-protonated carbons, respectively. A model compound, 1,2,3-trimethoxybenzene, is used to demonstrate these techniques, and the 13C principal values in 2,3-dimethylnaphthalene and Pocahontas coal are reported as typical examples.

Fano-like resonance in symmetry-broken gold nanotube dimer.

PubMed

Wu, DaJian; Jiang, ShuMin; Cheng, Ying; Liu, XiaoJun

2012-11-19

The influences of the symmetry-breaking on the plasmon resonance couplings in the isolated gold nanotube and the gold nanotube dimer have been investigated by means of the finite element method. It is found that the core offset of gold nanotubes leads to the red-shifts of the low energy modes and the enhanced near-field on the thin shell side of the symmetry-broken gold nanotube (SBGNT). In the weak coupling model of the SBGNT dimer, the interference of the bonding octupole mode of the dimer with the dipole modes causes a strong Fano-like resonance in scattering spectrum. The Fano dip shows a red-shift and becomes deep with the increase of the offset-value. In the strong coupling model of the SBGNT dimer, the coupling between two SBGNTs induces giant electric field enhancement at the gap of the dimer, which is much larger than that in the symmetry gold nanotube dimer. The SBGNT with larger offset-value exhibits stronger near-field at the "hot spot".

Changing carbon isotope ratio of atmospheric carbon dioxide: implications for food authentication.

PubMed

Peck, William H; Tubman, Stephanie C

2010-02-24

Carbon isotopes are often used to detect the addition of foreign sugars to foods. This technique takes advantage of the natural difference in carbon isotope ratio between C(3) and C(4) plants. Many foods are derived from C(3) plants, but the low-cost sweeteners corn and sugar cane are C(4) plants. Most adulteration studies do not take into account the secular shift of the carbon isotope ratio of atmospheric carbon dioxide caused by fossil fuel burning, a shift also seen in plant tissues. As a result statistical tests and threshold values that evaluate authenticity of foods based on carbon isotope ratios may need to be corrected for changing atmospheric isotope values. Literature and new data show that the atmospheric trend in carbon isotopes is seen in a 36-year data set of maple syrup analyses (n = 246), demonstrating that published thresholds for cane or corn sugar adulteration in maple syrup (and other foods) have become progressively more lenient over time.

Experimental and DFT studies of (E)-2-[2-(2,6-dichlorophenyl)ethenyl]-8-hydroxyquinoline: electronic and vibrational properties.

PubMed

Sun, Wenqi; Yuan, Guozan; Liu, Jingxin; Ma, Li; Liu, Chengbu

2013-04-01

The title molecule (E)-2-[2-(2,6-dichlorophenyl)ethenyl]-8-hydroxyquinoline (DPEQ) was synthesized and characterized by FT-IR, UV-vis, NMR spectroscopy. The molecular geometry, vibrational frequencies and gauge independent atomic orbital (GIAO) 1H and 13C NMR chemical shift values of the compound in the ground state have been calculated by using the density functional theory (DFT) method. All the assignments of the theoretical frequencies were performed by potential energy distributions using VEDA 4 program. The calculated results indicate that the theoretical vibrational frequencies, 1H and 13C NMR chemical shift values show good agreement with experimental data. The electronic properties like UV-vis spectral analysis and HOMO-LUMO analysis of DPEQ have been reported and compared with experimental data. Information about the size, shape, charge density distribution and site of chemical reactivity of the molecule has been obtained by mapping electron density isosurface with molecular electrostatic potential (MEP). Copyright © 2013 Elsevier B.V. All rights reserved.

Experimental and DFT studies of (E)-2-[2-(2,6-dichlorophenyl)ethenyl]-8-hydroxyquinoline: Electronic and vibrational properties

NASA Astrophysics Data System (ADS)

Sun, Wenqi; Yuan, Guozan; Liu, Jingxin; Ma, Li; Liu, Chengbu

2013-04-01

The title molecule (E)-2-[2-(2,6-dichlorophenyl)ethenyl]-8-hydroxyquinoline (DPEQ) was synthesized and characterized by FT-IR, UV-vis, NMR spectroscopy. The molecular geometry, vibrational frequencies and gauge independent atomic orbital (GIAO) 1H and 13C NMR chemical shift values of the compound in the ground state have been calculated by using the density functional theory (DFT) method. All the assignments of the theoretical frequencies were performed by potential energy distributions using VEDA 4 program. The calculated results indicate that the theoretical vibrational frequencies, 1H and 13C NMR chemical shift values show good agreement with experimental data. The electronic properties like UV-vis spectral analysis and HOMO-LUMO analysis of DPEQ have been reported and compared with experimental data. Information about the size, shape, charge density distribution and site of chemical reactivity of the molecule has been obtained by mapping electron density isosurface with molecular electrostatic potential (MEP).

Determination of ground and excited state dipole moments of dipolar laser dyes by solvatochromic shift method.

PubMed

Patil, S K; Wari, M N; Panicker, C Yohannan; Inamdar, S R

2014-04-05

The absorption and fluorescence spectra of three medium sized dipolar laser dyes: coumarin 478 (C478), coumarin 519 (C519) and coumarin 523 (C523) have been recorded and studied comprehensively in various solvents at room temperature. The absorption and fluorescence spectra of C478, C519 and C523 show a bathochromic and hypsochromic shifts with increasing solvent polarity indicate that the transitions involved are π→π(∗) and n→π(∗). Onsager radii determined from ab initio calculations were used in the determination of dipole moments. The ground and excited state dipole moments were evaluated by using solvatochromic correlations. It is observed that the dipole moment values of excited states (μe) are higher than corresponding ground state values (μg) for the solvents studied. The ground and excited state dipole moments of these probes computed from ab initio calculations and those determined experimentally are compared and the results are discussed. Copyright © 2013 Elsevier B.V. All rights reserved.

Linking budgets to desired academic outputs at Dalhousie University.

PubMed

MacDougall, B; Ruedy, J

1995-05-01

In 1993, faced with continuing university budget reductions and dissatisfaction with the budget-allocation process, the Faculty of Medicine at Dalhousie University undertook a financial planning process. The goal was to develop a new resource-allocation model to better link academic budget support to desired academic outputs over a three-year period. Department heads categorized academic outputs (e.g., teaching, research, administration, and subcategories of these), determined their relative values (expressed as percentages of the total department budget to be projected), and identified acceptable units of measuring the outputs (e.g., for teaching in the first and second years of medical school, the unit was the number of teaching hours). When dollar values were assigned to the units of measure, the new model was used to calculate budget allocations for all departments. However, many departments showed large negative shifts in their budgets; these shifts were too large to be achieved within three years because of departments' contractual obligations. Therefore, a practical limit in budget shift was determined. This adjustment permitted a three-year projection of academic budgets to be made for each department. The use of the resource-allocation model has achieved the Faculty's goal by creating a better rationalization of budgets to academic outputs, but carries the risk that departments might abandon essential but "undervalued" academic activities.

Application of shifted Jacobi pseudospectral method for solving (in)finite-horizon min-max optimal control problems with uncertainty

NASA Astrophysics Data System (ADS)

Nikooeinejad, Z.; Delavarkhalafi, A.; Heydari, M.

2018-03-01

The difficulty of solving the min-max optimal control problems (M-MOCPs) with uncertainty using generalised Euler-Lagrange equations is caused by the combination of split boundary conditions, nonlinear differential equations and the manner in which the final time is treated. In this investigation, the shifted Jacobi pseudospectral method (SJPM) as a numerical technique for solving two-point boundary value problems (TPBVPs) in M-MOCPs for several boundary states is proposed. At first, a novel framework of approximate solutions which satisfied the split boundary conditions automatically for various boundary states is presented. Then, by applying the generalised Euler-Lagrange equations and expanding the required approximate solutions as elements of shifted Jacobi polynomials, finding a solution of TPBVPs in nonlinear M-MOCPs with uncertainty is reduced to the solution of a system of algebraic equations. Moreover, the Jacobi polynomials are particularly useful for boundary value problems in unbounded domain, which allow us to solve infinite- as well as finite and free final time problems by domain truncation method. Some numerical examples are given to demonstrate the accuracy and efficiency of the proposed method. A comparative study between the proposed method and other existing methods shows that the SJPM is simple and accurate.

A comparative study between para-aminophenyl and ortho-aminophenyl benzothiazoles using NMR and DFT calculations.

PubMed

Pierens, G K; Venkatachalam, T K; Reutens, D

2014-08-01

Ortho-substituted and para-substituted aminophenyl benzothiazoles were synthesised and characterised using NMR spectroscopy. A comparison of the proton chemical shift values reveals significant differences in the observed chemical shift values for the NH protons indicating the presence of a hydrogen bond in all ortho-substituted compounds as compared to the para compounds. The presence of intramolecular hydrogen bond in the ortho amino substituted aminophenyl benzothiazole forces the molecule to be planar which may be an additional advantage in developing these compounds as Alzheimer's imaging agent because the binding to amyloid fibrils prefers planar compounds. The splitting pattern of the methylene proton next to the amino group also showed significant coupling to the amino proton consistent with the notion of the existence of slow exchange and hydrogen bond in the ortho-substituted compounds. This is further verified by density functional theory calculations which yielded a near planar low energy conformer for all the o-aminophenyl benzothiazoles and displayed a hydrogen bond from the amine proton to the nitrogen of the thiazole ring. A detailed analysis of the (1)H, (13)C and (15)N NMR chemical shifts and density functional theory calculated structures of the compounds are described. Copyright © 2014 John Wiley & Sons, Ltd.

Shifting from Production to Service to Experience-Based Operations

NASA Astrophysics Data System (ADS)

Angelis, Jannis; de Lima, Edson Pinheiro

This chapter covers the shift in focus of value added business operations from ­production to services, and in turn, to experience-based operations where customer involvement itself becomes part of the offering. The shift has significant implications for how businesses are managed. The greater service focus affects the firm's unique value proposition, which necessitates considerations on strategy, supplier relations, post-sale offerings and so on. Meanwhile, the inclusion of customer ­experiences affect the way operations are designed and employed so that these are structurally systematically captured and capitalised.

[Fluorescence peak shift corresponding to high chlorophyll concentrations in inland water].

PubMed

Duan, Hong-Tao; Ma, Rong-Hua; Zhang, Yuan-Zhi; Zhang, Bai

2009-01-01

Hyperspectral remote sensing offers the potential to detect water quality variables such as Chl-a by using narrow spectral channels of less than 10 nm, which could otherwise be masked by broadband satellites such as Landsat TM. Fluorescence peak of the red region is very important for the remote sensing of inland and coastal waters, which is unique to phytoplankton Chl-a that takes place in this region. Based on in situ water sampling and field spectral measurement from 2004 to 2006 in Nanhu Lake, the features of the spectral reflectance were analyzed in detail with peak position shift. The results showed: An exponential fitting model, peak position = a(Chl-a)b, was developed between chlorophyll-a concentration and fluorescence peak shift, where a varies between 686.11 and 686.29, while b between 0.0062 and 0.0065. It was found that the better the spectral resolution, the higher the precision of the model. Except that, the average of peak shift showed a high correlation with the average of different Chl-a grades, and the determination coefficient (R2) was higher than 0.81. It contributed significantly to the increase in the accuracy of the derivation of chlorophyll values from remote sensing data in Nanhu Lake. There is satisfactory correspondence between hyperspectral models and chl-a concentration, therefore, it is possible to monitor the water quality of Nanhu lake throngh the hyperspetral remote sensing data.

Cooling tower influence on the rainwater pH near a major power plant

Treesearch

Ta-Yung Li

1976-01-01

The dense network of 12 rainguages, covering an area of 6 km in diameter, was reinstalled near PEPCO's 710 MW Chalk Point power plant in southern Maryland. The rainwater samples were collected from July to December 1974. This second season's collection of rainwater samples were analyzed and results showed a general shifting of pH toward higher values since...

The Economy Goes to College: The Hidden Promise of Higher Education in the Post-Industrial Service Economy

ERIC Educational Resources Information Center

Carnevale, Anthony P.; Rose, Stephen J.

2015-01-01

This report explores the crucial transformation of the United States from an industrial to a post-industrial economy, with a particular focus on the shifting skill levels and incomes of American workers. It shows the increasing value of postsecondary education in today's economy and examines how workers have fared as the nation's focus has shifted…

Regional ionospheric model for improvement of navigation position with EGNOS

NASA Astrophysics Data System (ADS)

Swiatek, Anna; Tomasik, Lukasz; Jaworski, Leszek

The problem of insufficient accuracy of EGNOS correction for the territory of Poland, located at the edge of EGNOS range is well known. The EEI PECS project (EGNOS EUPOS Integration) assumed improving the EGNOS correction by using the GPS observations from Polish ASG-EUPOS stations. A ionospheric delay parameter is a part of EGNOS correction. The comparative analysis of TEC values obtained from EGNOS and regional permanent GNSS stations showed the systematic shift. The TEC from EGNOS correction is underestimated related to computed regional TEC value. The new-‘improved’ corrections computed based on regional model were substituted for the EGNOS correction for suitable message. Dynamic measurements managed using the Mobile GPS Laboratory (MGL), showed the improvement of navigation position with TEC regional model.

Contingent Attentional Capture

NASA Technical Reports Server (NTRS)

Remington, Roger; Folk, Charles L.

1994-01-01

Four experiments address the degree of top-down selectivity in attention capture by feature singletons through manipulations of the spatial relationship and featural similarity of target and distractor singletons in a modified spatial cuing paradigm. Contrary to previous studies, all four experiments show that when searching for a singleton target, an irrelevant featural singleton captures attention only when defined by the same feature value as the target. Experiments 2, 3, and 4 provide a potential explanation for this empirical discrepancy by showing that irrelevant singletons can produce distraction effects that are independent of shifts of spatial attention. The results further support the notion that attentional capture is contingent on top-down attention control settings but indicates that such settings can be instantiated at the level of feature values.

Optical properties of pure and PbSe doped TiS2 nanodiscs

NASA Astrophysics Data System (ADS)

Parvaz, M.; Islamuddin; Khan, Zishan H.

2018-06-01

Titanium disulfide, being one of the popular transition-metal dichalcogenide (TMD) materials, shows wonderful properties owing to tunable optical band gap. Pure and PbSe doped titanium disulfide nanodiscs have been synthesized by solid-state reaction method. FESEM, TEM and Raman images confirm the synthesis of nanodiscs. XRD spectra suggest the polycrystalline structure of as-prepared as well as PbSe doped TiS2 nanodiscs. PL spectra of the as-synthesized nanodiscs has been studied in the wavelength range of (300–550 nm), at room temperature. The position of the peak shifts towards the lower wavelength (blue shift) and intensity of the PL increases after the doping of PbSe, which may be due to a broadening of the optical band gap. UV–vis spectra has been used to calculate optical band gap of pure and PbSe doped titanium disulfide nanodiscs. The calculated value are found to be 1.93 eV and 2.03 eV respectively. Various optical constants such as n and k have been calculated. The value of extinction coefficient (k) of pure and doped titanium disulfide increases while the value of the refractive index (n) decreases with increase in photon energy.

Lignin from Micro- to Nanosize: Production Methods

PubMed Central

Beisl, Stefan; Miltner, Angela; Friedl, Anton

2017-01-01

Lignin is the second most abundant biopolymer after cellulose. It has long been obtained as a by-product of cellulose production in pulp and paper production, but had rather low added-value applications. A changing paper market and the emergence of biorefinery projects should generate vast amounts of lignin with the potential of value addition. Nanomaterials offer unique properties and the preparation of lignin nanoparticles and other nanostructures has therefore gained interest as a promising technique to obtain value-added lignin products. Due to lignin’s high structural and chemical heterogeneity, methods must be adapted to these different types. This review focuses on the ability of different formation methods to cope with the huge variety of lignin types and points out which particle characteristics can be achieved by which method. The current research’s main focus is on pH and solvent-shifting methods where the latter can yield solid and hollow particles. Solvent shifting also showed the capability to cope with different lignin types and solvents and antisolvents, respectively. However, process conditions have to be adapted to every type of lignin and reduction of solvent demand or the integration in a biorefinery process chain must be focused. PMID:28604584

Changes in patellofemoral alignment do not cause clinical impact after open-wedge high tibial osteotomy.

PubMed

Lee, Yong Seuk; Lee, Sang Bok; Oh, Won Seok; Kwon, Yong Eok; Lee, Beom Koo

2016-01-01

The objectives of this study were (1) to evaluate the clinical and radiologic outcomes of open-wedge high tibial osteotomy focusing on patellofemoral alignment and (2) to search for correlation between variables and patellofemoral malalignment. A total of 46 knees (46 patients) from 32 females and 14 males who underwent open-wedge high tibial osteotomy were included in this retrospective case series. Outcomes were evaluated using clinical scales and radiologic parameters at the last follow-up. Pre-operative and final follow-up values were compared for the outcome analysis. For the focused analysis of the patellofemoral joint, correlation analyses between patellofemoral variables and pre- and post-operative weight-bearing line (WBL), clinical score, posterior slope, Blackburn Peel ratio, lateral patellar tilt, lateral patellar shift, and congruence angle were performed. The minimum follow-up period was 2 years and median follow-up period was 44 months (range 24-88 months). The percentage of weight-bearing line was shifted from 17.2 ± 11.1 to 56.7 ± 12.7%, and it was statistically significant (p < 0.01). Regarding the clinical results, statistical significance was observed using all scores (p < 0.01). In the radiologic evaluation, patellar descent was observed with statistical significance (p < 0.01). Last follow-up lateral patellar tilt was decreased with statistical significance (p < 0.01). In correlation analysis between variables of patellofemoral malalignment, the pre-operative weight-bearing line showed an association with the change in lateral patellar tilt and lateral patellar shift (correlation coefficient: 0.3). After open-wedge high tibial osteotomy, clinical results showed improvement, compared to pre-operative values. The patellar tilt and lateral patellar shift were not changed; however, descent of the patella was observed. Therefore, mild patellofemoral problems should not be a contraindication of the open-wedge high tibial osteotomy. Case series, Level IV.

Correlation between the Temperature Dependence of Intrsinsic Mr Parameters and Thermal Dose Measured by a Rapid Chemical Shift Imaging Technique

PubMed Central

Taylor, Brian A.; Elliott, Andrew M.; Hwang, Ken-Pin; Hazle, John D.; Stafford, R. Jason

2011-01-01

In order to investigate simultaneous MR temperature imaging and direct validation of tissue damage during thermal therapy, temperature-dependent signal changes in proton resonance frequency (PRF) shifts, R2* values, and T1-weighted amplitudes are measured from one technique in ex vivo tissue heated with a 980-nm laser at 1.5T and 3.0T. Using a multi-gradient echo acquisition and signal modeling with the Stieglitz-McBride algorithm, the temperature sensitivity coefficient (TSC) values of these parameters are measured in each tissue at high spatiotemporal resolutions (1.6×1.6×4mm3,≤5sec) at the range of 25-61 °C. Non-linear changes in MR parameters are examined and correlated with an Arrhenius rate dose model of thermal damage. Using logistic regression, the probability of changes in these parameters is calculated as a function of thermal dose to determine if changes correspond to thermal damage. Temperature calibrations demonstrate TSC values which are consistent with previous studies. Temperature sensitivity of R2* and, in some cases, T1-weighted amplitudes are statistically different before and after thermal damage occurred. Significant changes in the slopes of R2* as a function of temperature are observed. Logistic regression analysis shows that these changes could be accurately predicted using the Arrhenius rate dose model (Ω=1.01±0.03), thereby showing that the changes in R2* could be direct markers of protein denaturation. Overall, by using a chemical shift imaging technique with simultaneous temperature estimation, R2* mapping and T1-W imaging, it is shown that changes in the sensitivity of R2* and, to a lesser degree, T1-W amplitudes are measured in ex vivo tissue when thermal damage is expected to occur according to Arrhenius rate dose models. These changes could possibly be used for direct validation of thermal damage in contrast to model-based predictions. PMID:21721063

Causes of Glacier Melt Extremes in the Alps Since 1949

NASA Astrophysics Data System (ADS)

Thibert, E.; Dkengne Sielenou, P.; Vionnet, V.; Eckert, N.; Vincent, C.

2018-01-01

Recent record-breaking glacier melt values are attributable to peculiar extreme events and long-term warming trends that shift averages upward. Analyzing one of the world's longest mass balance series with extreme value statistics, we show that detrending melt anomalies makes it possible to disentangle these effects, leading to a fairer evaluation of the return period of melt extreme values such as 2003, and to characterize them by a more realistic bounded behavior. Using surface energy balance simulations, we show that three independent drivers control melt: global radiation, latent heat, and the amount of snow at the beginning of the melting season. Extremes are governed by large deviations in global radiation combined with sensible heat. Long-term trends are driven by the lengthening of melt duration due to earlier and longer-lasting melting of ice along with melt intensification caused by trends in long-wave irradiance and latent heat due to higher air moisture.

Universal Faraday Rotation in HgTe Wells with Critical Thickness

NASA Astrophysics Data System (ADS)

Shuvaev, A.; Dziom, V.; Kvon, Z. D.; Mikhailov, N. N.; Pimenov, A.

2016-09-01

The universal value of the Faraday rotation angle close to the fine structure constant (α ≈1 /137 ) is experimentally observed in thin HgTe quantum wells with a thickness on the border between trivial insulating and the topologically nontrivial Dirac phases. The quantized value of the Faraday angle remains robust in the broad range of magnetic fields and gate voltages. Dynamic Hall conductivity of the holelike carriers extracted from the analysis of the transmission data shows a theoretically predicted universal value of σx y=e2/h , which is consistent with the doubly degenerate Dirac state. On shifting the Fermi level by the gate voltage, the effective sign of the charge carriers changes from positive (holes) to negative (electrons). The electronlike part of the dynamic response does not show quantum plateaus and is well described within the classical Drude model.

Resilience and Alternative Stable States of Tropical Forest Landscapes under Shifting Cultivation Regimes

PubMed Central

2015-01-01

Shifting cultivation is a traditional agricultural practice in most tropical regions of the world and has the potential to provide for human livelihoods while hosting substantial biodiversity. Little is known about the resilience of shifting cultivation to increasing agricultural demands on the landscape or to unexpected disturbances. To investigate these issues, we develop a simple social-ecological model and implement it with literature-derived ecological parameters for six shifting cultivation landscapes from three continents. Analyzing the model with the tools of dynamical systems analysis, we show that such landscapes exhibit two stable states, one characterized by high forest cover and agricultural productivity, and another with much lower values of these traits. For some combinations of agricultural pressure and ecological parameters both of these states can potentially exist, and the actual state of the forest depends critically on its historic state. In many cases, the landscapes’ ‘ecological resilience’, or amount of forest that could be destroyed without shifting out of the forested stability domain, declined substantially at lower levels of agricultural pressure than would lead to maximum productivity. A measure of ‘engineering resilience’, the recovery time from standardized disturbances, was independent of ecological resilience. These findings suggest that maximization of short-term agricultural output may have counterproductive impacts on the long-term productivity of shifting cultivation landscapes and the persistence of forested areas. PMID:26406907

Macrophysical climate models and Holocene hunter-gatherer subsistence shifts in Central Texas, USA

NASA Astrophysics Data System (ADS)

Mauldin, R. P.; Munoz, C.

2013-12-01

We use stable carbon isotopic values from bone collagen, as well as carbon values from carbonate extracted from bone apatite from 69 prehistoric human skeletal samples to investigate past resource use and climate relationships over the Middle and Late Holocene in Central Texas. Bone samples come from seven archaeological sites and samples date from 6,900 BP to the close of the prehistoric sequence at about 350 BP. Carbon isotopes from these samples suggest four broad dietary trends. From 6,900 through about 3,800 BP, carbon isotopes suggest a gradual increase in the consumption of resources that ultimately use a C3 photosynthetic pathway. A decline in δ13C in both collagen and carbonate values follows, suggesting a decrease in C3 resource use through roughly 2,900 BP. A variable, but once again increasing pattern on C3 resource use by prehistoric hunter-gatherers is indicated in bone isotopes through about 1,000 BP. After that date, a decrease in C3 resource dependence, with hints at greater subsistence diversity, is suggested through the close of the sequence at 350 BP. To assess the impact of climate shifts on this isotopic pattern, we developed a series of macrophysical climate models (MCM) for several locations in Central Texas focusing on fall, winter, and early spring precipitation. This fall-spring rainfall should closely determine C3 production. If subsistence shifts are responding to climate-induced changes in resource availability, then the measured hunter-gatherer carbon isotope trends summarized above should pattern with C3 production as monitored by the modeled fall-spring precipitation values. For the Middle Holocene portion of the sequence, the precipitation models suggest increasing C3 production, consistent with increasing C3 dependence shown in the isotopic data. A decline in C3 production between 3,900 and 3,000 BP in the models is also consistent with the isotopic decline at that point. After 3,000 BP, however, the coupling between fall-spring rainfall pattern and the bone isotope patterns begin to break down. Precipitation models suggest an essentially flat or slightly increasing pattern of production, while the isotopic data show a rapid C3 increase, and then a decline. This divergence is especially the case late in the sequence, with isotopic patterns showing rapid decreases in C3 resource use that are not consistent with the macrophysical climate models. If the precipitation models are accurate, the Late Holocene pattern of resource use reflects additional elements (e.g., regional population density changes, mobility shifts, social alliances) that require investigation. Standardized values. Data point colors reflect distinct climate trends.

Enhancing 18F-FDG-PET/CT analysis in lung cancer patients. Is CT-CT image fusion helpful in predicting pleural involvement? A pilot study.

PubMed

Kapfhammer, A; Winkens, T; Lesser, T; Reissig, A; Steinert, M; Freesmeyer, M

2015-01-01

To retrospectively evaluate the feasibility and value of CT-CT image fusion to assess the shift of peripheral lung cancers with/-out chest wall infiltration, comparing computed tomography acquisitions in shallow-breathing (SB-CT) and deep-inspiration breath-hold (DIBH-CT) in patients undergoing FDG-PET/CT for lung cancer staging. Image fusion of SB-CT and DIBH-CT was performed with a multimodal workstation used for nuclear medicine fusion imaging. The distance of intrathoracic landmarks and the positional shift of tumours were measured using semi-transparent overlay of both CT series. Statistical analyses were adjusted for confounders of tumour infiltration. Cutoff levels were calculated for prediction of no-/infiltration. Lateral pleural recessus and diaphragm showed the largest respiratory excursions. Infiltrating lung cancers showed more limited respiratory shifts than non-infiltrating tumours. A large respiratory tumour-motility accurately predicted non-infiltration. However, the tumour shifts were limited and variable, limiting the accuracy of prediction. This pilot fusion study proved feasible and allowed a simple analysis of the respiratory shifts of peripheral lung tumours using CT-CT image fusion in a PET/CT setting. The calculated cutoffs were useful in predicting the exclusion of chest wall infiltration but did not accurately predict tumour infiltration. This method can provide additional qualitative information in patients with lung cancers with contact to the chest wall but unclear CT evidence of infiltration undergoing PET/CT without the need of additional investigations. Considering the small sample size investigated, further studies are necessary to verify the obtained results.

Size effects in electronic and catalytic properties of unsupported palladium nanoparticles in electrooxidation of formic acid.

PubMed

Zhou, Wei Ping; Lewera, Adam; Larsen, Robert; Masel, Rich I; Bagus, Paul S; Wieckowski, Andrzej

2006-07-13

We report a combined X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), and chronoamperometry (CA) study of formic acid electrooxidation on unsupported palladium nanoparticle catalysts in the particle size range from 9 to 40 nm. The CV and CA measurements show that the most active catalyst is made of the smallest (9 and 11 nm) Pd nanoparticles. Besides the high reactivity, XPS data show that such nanoparticles display the highest core-level binding energy (BE) shift and the highest valence band (VB) center downshift with respect to the Fermi level. We believe therefore that we found a correlation between formic acid oxidation current and BE and VB center shifts, which, in turn, can directly be related to the electronic structure of palladium nanoparticles of different particle sizes. Clearly, such a trend using unsupported catalysts has never been reported. According to the density functional theory of heterogeneous catalysis, and mechanistic considerations, the observed shifts are caused by a weakening of the bond strength of the COOH intermediate adsorption on the catalyst surface. This, in turn, results in the increase in the formic acid oxidation rate to CO2 (and in the associated oxidation current). Overall, our measurements demonstrate the particle size effect on the electronic properties of palladium that yields different catalytic activity in the HCOOH oxidation reaction. Our work highlights the significance of the core-level binding energy and center of the d-band shifts in electrocatalysis and underlines the value of the theory that connects the center of the d-band shifts to catalytic reactivity.

Full-field stress determination in photoelasticity with phase shifting technique

NASA Astrophysics Data System (ADS)

Guo, Enhai; Liu, Yonggang; Han, Yongsheng; Arola, Dwayne; Zhang, Dongsheng

2018-04-01

Photoelasticity is an effective method for evaluating the stress and its spatial variations within a stressed body. In the present study, a method to determine the stress distribution by means of phase shifting and a modified shear-difference is proposed. First, the orientation of the first principal stress and the retardation between the principal stresses are determined in the full-field through phase shifting. Then, through bicubic interpolation and derivation of a modified shear-difference method, the internal stress is calculated from the point with a free boundary along its normal direction. A method to reduce integration error in the shear difference scheme is proposed and compared to the existing methods; the integration error is reduced when using theoretical photoelastic parameters to calculate the stress component with the same points. Results show that when the value of Δx/Δy approaches one, the error is minimum, and although the interpolation error is inevitable, it has limited influence on the accuracy of the result. Finally, examples are presented for determining the stresses in a circular plate and ring subjected to diametric loading. Results show that the proposed approach provides a complete solution for determining the full-field stresses in photoelastic models.

On shifted Jacobi spectral method for high-order multi-point boundary value problems

NASA Astrophysics Data System (ADS)

Doha, E. H.; Bhrawy, A. H.; Hafez, R. M.

2012-10-01

This paper reports a spectral tau method for numerically solving multi-point boundary value problems (BVPs) of linear high-order ordinary differential equations. The construction of the shifted Jacobi tau approximation is based on conventional differentiation. This use of differentiation allows the imposition of the governing equation at the whole set of grid points and the straight forward implementation of multiple boundary conditions. Extension of the tau method for high-order multi-point BVPs with variable coefficients is treated using the shifted Jacobi Gauss-Lobatto quadrature. Shifted Jacobi collocation method is developed for solving nonlinear high-order multi-point BVPs. The performance of the proposed methods is investigated by considering several examples. Accurate results and high convergence rates are achieved.

ROStoJAUSBridge Manual

DTIC Science & Technology

2012-03-01

Description A dass that handles Imming the JAUS header pmUon of JAUS messages. jaus_hmd~_msg is included as a data member in all JAUS messages. Member...scaleTolnt16 (float val, float low, float high) [related] Scales signed short value val, which is bounded by low and high. Shifts the center point of low...and high to zero, and shifts val accordingly. V a! is then up scaled by the ratio of the range of short values to the range of values from high to low

Shifting diet, shifting culture? A bioarchaeological approach to island dietary development on Iron-Age Öland, Baltic Sea.

PubMed

Wilhelmson, Helene

2017-06-01

The diet and subsistence in Iron-Age Öland is debated as earlier studies and different archaeological sources seemingly provide conflicting interpretations. The objectives of this study are therefore to: (i) add new insights on diet and (ii) investigate the chronological variation in detail. It is common in studies of diet to investigate differences between datasets defined by archaeological periods (determined by artefact typology), but it is rare to explore whether these dietary changes are, in fact, well correlated with these temporal categories or not. Stable isotope analysis of 108 individuals and 25 animals was used to interpret diet in comparison with data from earlier studies. Different values of TLE (Trophic Level Effect) for δ 15 N were compared for interpretations of diet. Of the 108 individuals, 42 were subjected to 14 C analysis in this study. The isotopes from Iron-Age animals on Öland indicate that the local, contemporary ecology is specific. The human isotope values show chronological development both when pooled in chronological groups by typology and by more specific 14 C chronology. The new samples of animals as well as the use of 5‰ TLE for δ 15 N values results in the diet reinterpreted as mainly domesticate-based, with at least two shifts in diet occurring in the Iron Age. The use of 14 C dates in connection with the stable isotope results indicates a dietary transition occurring between 200 BC and AD 200, a date range that spans two typologically determined time periods. © 2017 Wiley Periodicals, Inc.

Effect of a Surprising Downward Shift in Reinforcer Value on Stimulus Over-Selectivity in a Simultaneous Discrimination Procedure

ERIC Educational Resources Information Center

Reynolds, Gemma; Reed, Phil

2013-01-01

Stimulus over-selectivity refers to the phenomenon whereby behavior is controlled by a subset of elements in the environment at the expense of other equally salient aspects of the environment. The experiments explored whether this cue interference effect was reduced following a surprising downward shift in reinforcer value. Experiment 1 revealed…

Negotiating Academic Teacher Identity Shifts during Higher Education Contextual Change

ERIC Educational Resources Information Center

McNaughton, Susan Maree; Billot, Jennie

2016-01-01

Higher education teachers' roles and identities are constantly shifting in response to contextual change. Pedagogy, values, and professional and personal narratives of self are all affected, particularly by technological change. This paper explores the role and identity shifts of academics during the introduction of large-class videoconferencing.…

Study of the effective point of measurement for ion chambers in electron beams by Monte Carlo simulation

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

Wang, L. L. W.; Rogers, D. W. O.

In current dosimetry protocols for electron beams, for plane-parallel chambers, the effective point of measurement is at the front face of the cavity, and, for cylindrical chambers, it is at a point shifted 0.5r upstream from the cavity center. In this study, Monte Carlo simulations are employed to study the issue of effective point of measurement for both plane-parallel chambers and cylindrical thimble chambers in electron beams. It is found that there are two ways of determining the position of the effective point of measurement: One is to match the calculated depth-ionization curve obtained from a modeled chamber to amore » calculated depth-dose curve; the other is to match the electron fluence spectrum in the chamber cavity to that in the phantom. For plane-parallel chambers, the effective point of measurement determined by the first method is generally not at the front face of the chamber cavity, which is obtained by the second method, but shifted downstream toward the cavity center by an amount that could be larger than one-half a millimeter. This should not be ignored when measuring depth-dose curves in electron beams. For cylindrical chambers, these two methods also give different positions of the effective point of measurement: The first gives a shift of 0.5r, which is in agreement with measurements for high-energy beams and is the same as the value currently used in major dosimetry protocols; the latter gives a shift of 0.8r, which is closer to the value predicted by a theoretical calculation assuming no-scatter conditions. The results also show that the shift of 0.8r is more appropriate if the cylindrical chamber is to be considered as a Spencer-Attix cavity. In electron beams, since the water/air stopping-power ratio changes with depth in a water phantom, the difference of the two shifts (0.3r) will lead to an incorrect evaluation of the water/air stopping-power ratio at the point of measurement, thus resulting in a systematic error in determining the absorbed dose by cylindrical chambers. It is suggested that a shift of 0.8r be used for electron beam calibrations with cylindrical chambers and a shift of 0.4r-0.5r be used for depth-dose measurements.« less

Study of the effective point of measurement for ion chambers in electron beams by Monte Carlo simulation.

PubMed

Wang, L L W; Rogers, D W O

2009-06-01

In current dosimetry protocols for electron beams, for plane-parallel chambers, the effective point of measurement is at the front face of the cavity, and, for cylindrical chambers, it is at a point shifted 0.5r upstream from the cavity center. In this study, Monte Carlo simulations are employed to study the issue of effective point of measurement for both plane-parallel chambers and cylindrical thimble chambers in electron beams. It is found that there are two ways of determining the position of the effective point of measurement: One is to match the calculated depth-ionization curve obtained from a modeled chamber to a calculated depth-dose curve; the other is to match the electron fluence spectrum in the chamber cavity to that in the phantom. For plane-parallel chambers, the effective point of measurement determined by the first method is generally not at the front face of the chamber cavity, which is obtained by the second method, but shifted downstream toward the cavity center by an amount that could be larger than one-half a millimeter. This should not be ignored when measuring depth-dose curves in electron beams. For cylindrical chambers, these two methods also give different positions of the effective point of measurement: The first gives a shift of 0.5r, which is in agreement with measurements for high-energy beams and is the same as the value currently used in major dosimetry protocols; the latter gives a shift of 0.8r, which is closer to the value predicted by a theoretical calculation assuming no-scatter conditions. The results also show that the shift of 0.8r is more appropriate if the cylindrical chamber is to be considered as a Spencer-Attix cavity. In electron beams, since the water/air stopping-power ratio changes with depth in a water phantom, the difference of the two shifts (0.3r) will lead to an incorrect evaluation of the water/air stopping-power ratio at the point of measurement, thus resulting in a systematic error in determining the absorbed dose by cylindrical chambers. It is suggested that a shift of 0.8r be used for electron beam calibrations with cylindrical chambers and a shift of 0.4r-0.5r be used for depth-dose measurements.

Mediterranean coastal dune vegetation: Are disturbance and stress the key selective forces that drive the psammophilous succession?

NASA Astrophysics Data System (ADS)

Ciccarelli, Daniela

2015-11-01

Plant communities of coastal dunes are distributed along a characteristic sea-inland gradient. Generally, there is a shift from annual and short height species with small leaves in the initial successional stages to perennial tall shrubs with tough leaves in later phases. Assessing the community-weighted mean (CWM) trait values is used in plant ecology to describe ecosystem properties especially during succession. In particular, CSR (Competitive, Stress-tolerant, and Ruderal strategy) classification allows us to explore community functional shifts in terms of disturbance, stress and competition selective forces. The functional basis of the psammophilous succession was studied based on the following questions: (1) Can we circumscribe different functional types among plant species of Mediterranean coastal dunes? (2) How do CWM trait values vary along the environmental sea-inland gradient? (3) What is the relative importance of competition, stress and disturbance in the processes of plant community assembling? (4) Can we postulate that along primary successions there is generally a shift from ruderality to stress-tolerance? An explorative analysis of functional groups was performed by Non-Metric Multidimensional Scaling (NMDS) analysing nine morpho-functional traits measured for 45 taxa from 880 dune plots localised in Tuscany (central Italy, Europe). NMDS ordination showed a scattered distribution of psammophytes that could not be delimited in precise plant functional types. The first NMDS axis has been interpreted as a leaf economics axis because it was correlated to leaf area (LA) and leaf dry matter content (LDMC), while the second one was a plant size axis because of its correlation with canopy height. Along the sea-inland gradient, pioneer plant communities of upper beach were dominated by ruderals (with the lowest values of LDMC and specific leaf area - SLA), well-adapted to the harsh environmental conditions of coastal dunes. More distant from the sea, where ecological conditions were less extreme, late-successional communities of backdunes were characterised by the prevalence of stress-tolerance. This study suggested that psammophytes have evolved not a single but multiple adaptive strategies showing a high degree of functional diversity and complexity. Moreover, CSR classification supported the hypothesis of a functional shift from R-strategists in early successional stages to S-strategists in late-successional communities along a primary succession.

Combined effect of pH and heating conditions on the physical properties of Alaska pollock surimi gels.

PubMed

Lee, Myeong Gi; Yoon, Won Byong; Park, Jae W

2017-06-01

Physical properties of Alaska pollock surimi paste were investigated as affected by pH (4.0 and 6.0-10.0) and heating conditions (slow and fast). The highest values of gel strength and deformability, as shown by breaking force and penetration distance, were obtained at pH 7.5-8.0, while the lowest values were at pH 10.0 followed by pH 6.0 and pH 6.5, respectively. Two-step slow heating process increased the breaking strength value nearly two times higher than one-step fast heating. The effect of pH was strikingly high at pH 7.5 when gels were prepared using 2-step heating, indicating the pH dependence of endogenous transglutaminase. However, the highest gel strength was obtained at pH 8.0 when gels were prepared in fast heating. Whiteness value (L - 3b*) increased significantly (p < .05) as pH increased from 6.0 to 6.5, but thereafter decreased significantly (p < .05) as pH increased. L* value (lightness) and b* value (yellowness) continuously decreased as the pH is shifted from 6.0 to 10. Fast heated gels showed the lowest yellowness, resulting in whiter appearance, probably due to the effect of reduced browning reaction. The uniqueness of this study was to measure the combined effect of pH and heating conditions on the gel texture and color. There were various studies dealing with pH or heating conditions independently. As the primary character for surimi seafood is gel texture and color. The highest values of gel strength and deformability, as shown by breaking force and penetration distance, were obtained at pH 7.5-8.0, while the lowest values were at pH 10.0 followed by pH 6.0 and pH 6.5, respectively. Two-step slow heating process increased the breaking strength value nearly two times higher than one-step fast heating. Whiteness value (L - 3b*) increased significantly as pH increased from 6.0 to 6.5, but thereafter decreased significantly as pH increased. L* value (lightness) and b* value (yellowness) continuously decreased as the pH is shifted from 6.0 to 10. Fast heated gels showed the lowest yellowness, resulting in whiter appearance. © 2016 Wiley Periodicals, Inc.

N-(4-Nitrobenzoyl)-N'-(1,5-dimethyl-3-oxo-2-phenyl-1H-3(2H)-pyrazolyl)-thiourea hydrate: Synthesis, spectroscopic characterization, X-ray structure and DFT studies

NASA Astrophysics Data System (ADS)

Arslan, N. Burcu; Kazak, Canan; Aydın, Fatma

2012-04-01

The title molecule (C19H17N5O4S·H2O) was synthesized and characterized by IR-NMR spectroscopy, MS and single-crystal X-ray diffraction. The molecular geometry, vibrational frequencies and gauge-independent atomic orbital (GIAO) 1H and 13C NMR chemical shift values of the compound in the ground state have been calculated by using the density functional theory (DFT) method with 6-31G(d) basis set, and compared with the experimental data. All the assignments of the theoretical frequencies were performed by potential energy distributions using VEDA 4 program. The calculated results show that the optimized geometries can well reproduce the crystal structural parameters, and the theoretical vibrational frequencies and 1H and 13C NMR chemical shift values show good agreement with experimental data. To determine conformational flexibility, the molecular energy profile of the title compound was obtained with respect to the selected torsion angle, which was varied from -180° to +180° in steps of 10°. Besides, molecular electrostatic potential (MEP), frontier molecular orbitals (FMO) analysis and thermodynamic properties of the compound were investigated by theoretical calculations.

[Burnout in volunteer health workers].

PubMed

Argentero, P; Bonfiglio, N S; Pasero, R

2006-01-01

While diverse studies carried out in nursing and medical personnel have demonstrated that health workers can be subject to burnout, little effort has been focused on investigating burnout in volunteer hospital workers. The aim of the present study was to verify if burnout exists with volunteer auxiliary personnel and investigate what organizational conditions may favour it. The study was carried out on 80 volunteer workers of the Red Cross of Mortara (PV), subdivided into two categories: those performing emergency interventions and those performing routine services. For the evaluation of burnout, the Italian version of the Maslach Burnout Inventory was used, together with a qualitative type of methodology. A 5-factor multivariate analysis (sex x shift x team x seniority x role), having as dependent variables the three scales of the MBI, showed that the highest values of depersonalization and fulfillment are found in the emergency team, and that subjects with least seniority are those who are least satisfied or fulfilled. The category of team-leader resulted as that with the highest values of emotional burnout, while sex- and shift-based differences were restricted to routine service workers. Despite these differences, findings showed that subjects are minimally affected by problems linked to burnout, although some relational and organizational difficulties emerged with the medical staff that underlie a certain degree of professional dissatisfaction.

L alpha, L beta /of H I/, K and H /of MG II/, K and H /of CA II/ observations in a quiescent prominence with the OSO-8 LPSP instrument

NASA Astrophysics Data System (ADS)

Vial, J. C.; Martres, M. J.; Salm-Platzer, J.

1981-04-01

A sequence of images taken at different positions in the resonance lines of Ca II, Mg II, and H I was obtained over a quiescent prominence with the LPSP instrument on OSO-8. Ca II K (and H) profiles are reconstructed at different locations in the prominence with a (10 × 5) arc sec2 resolution. Significant variations of FWHM and line shifts are found: FWHM range from 0.14 Å to 0.5 Å; blue shifts reach about 14 km s-1. The ratio of K to H absolute intensities shows a large spread around the average value of 1.2. The same ratio for the Mg II lines in the whole prominence is higher (1.7), a fact already noticed at the edge of an active prominence (Vial et al., 1979). The ionization degree, as measured by the Lα/Ca K ratio, shows noticeable variations within the prominence. The La intensity is about 0.3 times the intensity measured in the quiet Sun, and the Lα/Lβ ratio is less than one half the disk value. These results indicate important variations of the thermal conditions inside the prominence.

Relationship between shift work and the onset of rheumatoid arthritis

PubMed Central

Hedström, Anna Karin; Åkerstedt, Torbjörn; Klareskog, Lars; Alfredsson, Lars

2017-01-01

Background Environmental factors play a prominent role in rheumatoid arthritis (RA) aetiology. Shift work has previously been associated with increased RA risk in females. The aim of this study was to investigate the potential association, including a dose–response association, between permanent night shift work, rotating shift work and day-oriented shift work and risk of developing anticitrullinated peptide antibodies (ACPA)-positive and ACPA-negative RA. Methods The present report is based on a population-based, case–control study with incident cases of RA (1951 cases and 2225 controls matched by age, gender and residential area). Using logistic regression, occurrence of RA among subjects who have been exposed to different kinds of shift work was compared with that among those who have never been exposed by calculating the OR with a 95% CI. Results Rotating shift work and day-oriented shift work increased the risk of developing ACPA-positive RA (OR 1.3, 95% CI 1.0 to 1.7 and OR 1.3, 95% CI 1.0 to 1.6), but not ACPA-negative RA. Permanent night shift work appeared to be a protective factor both against ACPA-positive RA (OR 0.7, 95% CI 0.6 to 0.9) and ACPA-negative RA (OR 0.8, 95% CI 0.6 to 1.0). For both subsets of RA, significant trends showed a lower risk of developing RA with increasing duration of permanent night shift work (p value for trend 0.002 vs 0.04). Conclusions Sleep restriction as a consequence of shift work is associated with several biological effects among which changes in melatonin production may be involved. The present epidemiological findings of a complex relationship between sleep patterns and different forms of RA may be of importance for increasing the understanding of the pathophysiology of RA. PMID:29225920

Stable isotope analysis of CO2 in breath indicates metabolic fuel shifts in torpid arctic ground squirrels.

PubMed

Lee, Trixie N; Richter, Melanie M; Williams, Cory T; Tøien, Øivind; Barnes, Brian M; O'Brien, Diane M; Buck, C Loren

2017-07-01

Stable carbon isotope ratios (δ 13 C) in breath show promise as an indicator of immediate metabolic fuel utilization in animals because tissue lipids have a lower δ 13 C value than carbohydrates and proteins. Metabolic fuel consumption is often estimated using the respiratory exchange ratio (RER), which has lipid and carbohydrate boundaries, but does not differentiate between protein and mixed fuel catabolism at intermediate values. Because lipids have relatively low δ 13 C values, measurements of stable carbon isotopes in breath may help distinguish between catabolism of protein and mixed fuel that includes lipid. We measured breath δ 13 C and RER concurrently in arctic ground squirrels (Urocitellus parryii) during steady-state torpor at ambient temperatures from -2 to -26°C. As predicted, we found a correlation between RER and breath δ 13 C values; however, the range of RER in this study did not reach intermediate levels to allow further resolution of metabolic substrate use with the addition of breath δ 13 C measurements. These data suggest that breath δ 13 C values are 1.1‰ lower than lipid tissue during pure lipid metabolism. From RER, we determined that arctic ground squirrels rely on nonlipid fuel sources for a significant portion of energy during torpor (up to 37%). The shift toward nonlipid fuel sources may be influenced by adiposity of the animals in addition to thermal challenge. Copyright © 2017 Elsevier Inc. All rights reserved.

Tunability of temperature-dependent absorption in a graphene-based hybrid nanostructure cavity

NASA Astrophysics Data System (ADS)

Rashidi, Arezou; Namdar, Abdolrahman

2018-04-01

Enhanced absorption is obtained in a hybrid nanostructure composed of graphene and one-dimensional photonic crystal as a cavity in the visible wavelength range thanks to the localized electric field around the defect layers. The temperature-induced wavelength shift is revealed in the absorption spectra in which the peak wavelength is red-shifted by increasing the temperature. This temperature dependence comes from the thermal expansion and thermo-optical effects in the constituent layers of the structure. Moreover, the absorption peaks can be adjusted by varying the incident angle. The results show that absorption is sensitive to TE/TM polarization and its peak values for the TE mode are higher than the TM case. Also, the peak wavelength is blue-shifted by increasing the incident angle for both polarizations. Finally, the possibility of tuning the absorption using the electro-optical response of graphene sheets is discussed in detail. We believe our study may be beneficial for designing tunable graphene-based temperature-sensitive absorbers.

The Polarization Orientation Shift Estimation and Compensation of PolSAR Data in Forest Area

NASA Astrophysics Data System (ADS)

Zhao, Lei; Chen, Erxue; Li, Zengyuan; Li, Lan; Gu, Xinzhi

2016-08-01

Polarization orientation angle (POA) is a major parameter of electromagnetic wave. This angle will be shift due to azimuth slopes, which will affect the radiometric quality of PolSAR data. Under the assumption of reflection symmetrical medium, the shift value of polarization orientation angle (POAs) can be estimated by Circular Polarization Method (CPM). Then, the shift angle can be used to compensate PolSAR data or extract DEM information. However, it is less effective when using high-frequency SAR (L-, C-band) in the forest area. The main reason is that the polarization orientation angle shift of forest area not only influenced by topography, but also affected by the forest canopy. Among them, the influence of the former belongs to the interference information should be removed, but the impact of the latter belongs to the polarization feature information needs to be retained. The ALOS2 PALSAR2 L-band full polarimetric SAR data was used in this study. Base on the Circular Polarization and DEM-based method, we analyzed the variation of shift value of polarization orientation angle and developed the polarization orientation shift estimation and compensation of PolSAR data in forest.

Noise level in a neonatal intensive care unit in Santa Marta - Colombia.

PubMed Central

Garrido Galindo, Angélica Patricia; Velez-Pereira, Andres M

2017-01-01

Abstract Introduction: The environment of neonatal intensive care units is influenced by numerous sources of noise emission, which contribute to raise the noise levels, and may cause hearing impairment and other physiological and psychological changes on the newborn, as well as problems with care staff. Objective: To evaluate the level and sources of noise in the neonatal intensive care unit. Methods: Sampled for 20 consecutive days every 60 seconds in A-weighting curves and fast mode with a Type I sound level meter. Recorded the average, maximum and minimum, and the 10th, 50th and 90th percentiles. The values are integrated into hours and work shift, and studied by analysis of variance. The sources were characterized in thirds of octaves. Results: The average level was 64.00 ±3.62 dB(A), with maximum of 76.04 ±5.73 dB(A), minimum of 54.84 ±2.61dB(A), and background noise of 57.95 ±2.83 dB(A). We found four sources with levels between 16.8-63.3 dB(A). Statistical analysis showed significant differences between the hours and work shift, with higher values in the early hours of the day. Conclusion: The values presented exceed the standards suggested by several organizations. The sources identified and measured recorded high values in low frequencies. PMID:29213154

Complex networks: Effect of subtle changes in nature of randomness

NASA Astrophysics Data System (ADS)

Goswami, Sanchari; Biswas, Soham; Sen, Parongama

2011-03-01

In two different classes of network models, namely, the Watts Strogatz type and the Euclidean type, subtle changes have been introduced in the randomness. In the Watts Strogatz type network, rewiring has been done in different ways and although the qualitative results remain the same, finite differences in the exponents are observed. In the Euclidean type networks, where at least one finite phase transition occurs, two models differing in a similar way have been considered. The results show a possible shift in one of the phase transition points but no change in the values of the exponents. The WS and Euclidean type models are equivalent for extreme values of the parameters; we compare their behaviour for intermediate values.

Pulpit Responses to Contemporary Issues: The On-Going Rhetoric of Dr. Martin Luther King.

ERIC Educational Resources Information Center

Fadely, Dean; Greene, Ronald W.

Many theoreticians have indicated that a major task of the nonpresumptive rhetor is to gain presumption, thereby shifting the burden of proof to the opposition. Rhetorically, Martin Luther King, Jr., sought to effect this shift in the burden of proof through the use of hierarchies of values. At the top of his value system was the love of God. The…

A Study on the Learning Processes in Discrimination Shift Learning of Children with Mental Retardation: From the Point of Developmental View of "Logical Manipulation by Classification."

ERIC Educational Resources Information Center

Kanno, Atsushi

1989-01-01

The study was designed to investigate the learning processes in discrimination shift learning, in terms of developmental views of "logical manipulation by classification." Tasks comparing sizes of intradimensional value-classes and comparing sizes of interdimensional value-classes were devised in order to measure subjects' levels of…

Transcranial Duplex Sonography Predicts Outcome following an Intracerebral Hemorrhage.

PubMed

Camps-Renom, P; Méndez, J; Granell, E; Casoni, F; Prats-Sánchez, L; Martínez-Domeño, A; Guisado-Alonso, D; Martí-Fàbregas, J; Delgado-Mederos, R

2017-08-01

Several radiologic features such as hematoma volume are related to poor outcome following an intracerebral hemorrhage and can be measured with transcranial duplex sonography. We sought to determine the prognostic value of transcranial duplex sonography in patients with intracerebral hemorrhage. We conducted a prospective study of patients diagnosed with spontaneous intracerebral hemorrhage. Transcranial duplex sonography examinations were performed within 2 hours of baseline CT, and we recorded the following variables: hematoma volume, midline shift, third ventricle and lateral ventricle diameters, and the pulsatility index in both MCAs. We correlated these data with the CT scans and assessed the prognostic value of the transcranial duplex sonography measurements. We assessed early neurologic deterioration during hospitalization and mortality at 1-month follow-up. We included 35 patients with a mean age of 72.2 ± 12.8 years. Median baseline hematoma volume was 9.85 mL (interquartile range, 2.74-68.29 mL). We found good agreement and excellent correlation between transcranial duplex sonography and CT when measuring hematoma volume ( r = 0.791; P < .001) and midline shift ( r = 0.827; P < .001). The logistic regression analysis with transcranial duplex sonography measurements showed that hematoma volume was an independent predictor of early neurologic deterioration (OR, 1.078; 95% CI, 1.023-1.135) and mortality (OR, 1.089; 95% CI, 1.020-1.160). A second regression analysis with CT variables also demonstrated that hematoma volume was associated with early neurologic deterioration and mortality. When we compared the rating operation curves of both models, their predictive power was similar. Transcranial duplex sonography showed an excellent correlation with CT in assessing hematoma volume and midline shift in patients with intracerebral hemorrhage. Hematoma volume measured with transcranial duplex sonography was an independent predictor of poor outcome. © 2017 by American Journal of Neuroradiology.

Effect of pH on the structural, optical and morphological properties of Ga-doped ZnO nanoparticles by reflux precipitation method

NASA Astrophysics Data System (ADS)

Ungula, J.; Dejene, B. F.; Swart, H. C.

2018-04-01

Gallium-doped zinc oxide nanoparticles (GZO NPs) were synthesized by the reflux precipitation method at 1, 3, 5, 7 and 8 pH conditions of Ga/Zn precursor solution (Ga/Zn sol.). Analysis of X-ray diffraction (XRD) spectra showed that the diffraction peak intensities of GZO NPs increased and the crystallite sizes varied from 11 to 27 nm with an increase in the pH of the Zn/Ga sol. Scanning electron microscopy micrographs showed agglomerated tiny particles that formed on big slabs of nanorods at the lower pH, but fine and enlarged particles on nano-spherical bases formed at the higher pH values. The photoluminescence exciton peak intensities of the GZO NPs and their respective FWHM increased to a maximum at the 5 pH and then reduced slightly as the solution got more basic. The increase of the deep level peak intensities with the increase in the pH followed the XRD diffraction intensity results. It was observed that both the exciton and DLE peaks emission positions shifted to lower wavelengths up to the 5 pH and then red shifted for a further increase in the pH values. The UV-vis analysis also demonstrated that the optical properties of the GZO NPs improved with the increase Ga/Zn sol. pH, as shown by the blue shift of the absorption edge of the reflectance spectra. The band gap energy was tuned from 3.18 to 3.31 eV with the increase in the pH from 1 to 5. An additional increase in the pH yielded no significant change in the optical properties of the GZO NPs.

Population age and initial density in a patchy environment affect the occurrence of abrupt transitions in a birth-and-death model of Taylor's law

USGS Publications Warehouse

Jiang, Jiang; DeAngelis, Donald L.; Zhang, B.; Cohen, J.E.

2014-01-01

Taylor's power law describes an empirical relationship between the mean and variance of population densities in field data, in which the variance varies as a power, b, of the mean. Most studies report values of b varying between 1 and 2. However, Cohen (2014a) showed recently that smooth changes in environmental conditions in a model can lead to an abrupt, infinite change in b. To understand what factors can influence the occurrence of an abrupt change in b, we used both mathematical analysis and Monte Carlo samples from a model in which populations of the same species settled on patches, and each population followed independently a stochastic linear birth-and-death process. We investigated how the power relationship responds to a smooth change of population growth rate, under different sampling strategies, initial population density, and population age. We showed analytically that, if the initial populations differ only in density, and samples are taken from all patches after the same time period following a major invasion event, Taylor's law holds with exponent b=1, regardless of the population growth rate. If samples are taken at different times from patches that have the same initial population densities, we calculate an abrupt shift of b, as predicted by Cohen (2014a). The loss of linearity between log variance and log mean is a leading indicator of the abrupt shift. If both initial population densities and population ages vary among patches, estimates of b lie between 1 and 2, as in most empirical studies. But the value of b declines to ~1 as the system approaches a critical point. Our results can inform empirical studies that might be designed to demonstrate an abrupt shift in Taylor's law.

Increasing off-service resident productivity while on their emergency department rotation using shift cards.

PubMed

Chakravarthy, Bharath; Posadas, Emerson; Ibrahim, Deena; McArthur, Kurt; Osborn, Megan; Hoonpongsimanont, Wirachin; Wong, Andrew; Lotfipour, Shahram

2015-04-01

Differences in productivity between off-service residents rotating in the emergency department (ED) and their emergency medicine (EM) resident counterparts have never been directly quantified. We sought to quantify the difference between off-service residents rotating in the ED and their EM resident counterparts. We also sought to find whether shift cards could be used to increase the productivity of off-service residents rotating in the ED. This is a prospective cohort study conducted at an urban, tertiary, Level I trauma center. We implemented the use of shift cards for off-service residents during their EM rotation. Completion of the shift card involved recording patients seen and their dispositions, procedures done, and documenting a learned bedside teaching point from their shift that day. Productivity was measured in terms of patients seen per hour (PPH) and relative value units per hour (RVU/h). Off-service residents showed a productivity of 0.529 PPH (95% confidence interval [CI] 0.493-0.566) and 1.40 RVU/h (95% CI 1.28-1.53) prior to implementation of shift cards. With the introduction of shift cards, productivity increased to 0.623 PPH (95% CI 0.584-0.663, p = 0.001) and 1.77 RVU/h (95% CI 1.64-1.91, p = 0.001). In comparison, first year EM resident productivity was 0.970 PPH (95% CI 0.918-1.02) and 3.01 RVU/h (95% CI 2.83-3.19). Shift cards can be used to foster motivation for off-service residents rotating in the ED, and is a simple and cost-effective method to improve system-based practices and utilization of resources. Copyright © 2015 Elsevier Inc. All rights reserved.

Explaining observed red and blue-shifts using multi-stranded coronal loops

NASA Astrophysics Data System (ADS)

Regnier, S.; Walsh, R. W.; Pearson, J.

2012-03-01

Magnetic plasma loops have been termed the building blocks of the solar atmosphere. However, it must be recognised that if the range of loop structures we can observe do consist of many ''sub-resolution'' elements, then current one-dimensional hydrodynamic models are really only applicable to an individual plasma element or strand. Thus a loop should be viewed is an amalgamation of these strands. They could operate in thermal isolation from one another with a wide range of temperatures occurring across the structural elements. This scenario could occur when the energy release mechanism consists of localised, discrete bursts of energy that are due to small scale reconnection sites within the coronal magnetic field- the nanoflare coronal heating mechanism. These energy bursts occur in a time-dependent manner, distributed along the loop/strand length, giving a heating function that depends on space and time. An important observational discovery with the Hinode/EIS spectrometer is the existence of red and blue-shifts in coronal loops depending on the location of the footpoints (inner or outer parts of the active region), and the temperature of the emission line in which the Doppler shifts are measured. Based on the multi-stranded model developed by Sarkar and Walsh (2008, ApJ, 683, 516), we show that red and blue-shifts exist in different simulated Hinode/EIS passbands: cooler lines (OV-SiVII) being dominated by red-shifts, whilst hotter lines (FeXV-CaXVII) are a combination of both. The distribution of blue-shifts depends on the energy input and not so much on the heating location. Characteristic Doppler shifts generated fit well with observed values. We also simulate the Hinode/EIS rasters to closely compare our simulation with the observations. Even if not statistically significant, loops can have footpoints with opposite Doppler shifts.

Accounting for phase drifts in SSVEP-based BCIs by means of biphasic stimulation.

PubMed

Wu, Hung-Yi; Lee, Po-Lei; Chang, Hsiang-Chih; Hsieh, Jen-Chuen

2011-05-01

This study proposes a novel biphasic stimulation technique to solve the issue of phase drifts in steady-state visual evoked potential (SSVEPs) in phase-tagged systems. Phase calibration was embedded in stimulus sequences using a biphasic flicker, which is driven by a sequence with alternating reference and phase-shift states. Nine subjects were recruited to participate in off-line and online tests. Signals were bandpass filtered and segmented by trigger signals into reference and phase-shift epochs. Frequency components of SSVEP in the reference and phase-shift epochs were extracted using the Fourier method with a 50% overlapped sliding window. The real and imaginary parts of the SSVEP frequency components were organized into complex vectors in each epoch. Hotelling's t-square test was used to determine the significances of nonzero mean vectors. The rejection of noisy data segments and the validation of gaze detections were made based on p values. The phase difference between the valid mean vectors of reference and phase-shift epochs was used to identify user's gazed targets in this system. Data showed an average information transfer rate of 44.55 and 38.21 bits/min in off-line and online tests, respectively. © 2011 IEEE

Context effects on tempo and pleasantness judgments for Beatles songs.

PubMed

Rashotte, Matthew A; Wedell, Douglas H

2012-04-01

Context effects on tempo and pleasantness judgments of different tempos were demonstrated in three experiments using Beatles songs. In Experiments 1 and 2, we explored how listening to versions of the same song that were played at different tempos affected tempo and pleasantness ratings. In both experiments, contrast effects were found on judgments of tempo, with target tempos rated faster when context tempos were slow than when they were fast. In both experiments, we also showed that the peak of the pleasantness rating function shifted toward the values of the context tempos, reflecting disordinal context effects on pleasantness relationships. Familiarity with the songs did not moderate these effects, and shifts in tempo ratings did not correlate with shifts in most pleasant target tempos when context was manipulated within subjects. In Experiment 3, we examined how manipulations of context tempos for one song affected judgments of the same song as compared with judgments of other more or less similar songs. For tempo ratings, contrast effects transferred to ratings of a similar song, but for pleasantness ratings, assimilative shifts of ideals were found only for the same song and not for similar songs. This pattern of results was supportive of independent bases for the two context effects.

Generation of straight-line shifting bright-dark soliton trains with a wide dip in the symmetric center or dark solitons in optical fibers

NASA Astrophysics Data System (ADS)

Zhong, Xianqiong; Yao, Na; Sheng, Jia'nan; Cheng, Ke

2018-02-01

Nonlinear evolutions of dark soliton pulses with initially constant frequency chirps are investigated numerically for different soliton orders and chirp parameters in different dispersion regimes of optical fibers. The results show interestingly that, in the normal dispersion regime, the evolution properties remain unchanged apart from their straight-line shifts of the temporal trajectories compared with the chirp-free case. While in the anomalous dispersion regime, the dark solitons can evolve to bright-dark soliton trains with a wide black soliton in the symmetric center. The longer the distance, the more the pulse number. The larger the soliton order, the more the pulse number at the same distance. Similarly, straight-line shift of the temporal trajectory of the bright-dark soliton trains will also appear. The shifting amount and direction depend on the absolute value and the sign of the chirp parameter, respectively. This result inspires people to generate bright-dark soliton trains by using ordinary passive optical fibers instead of fiber lasers. Besides, this work also provides us an alternative approach to guide the formed solitons or soliton trains to move their temporal trajectories along straight lines.

Mechanism and Characteristics of Humidity Sensing with Polyvinyl Alcohol-Coated Fiber Surface Plasmon Resonance Sensor.

PubMed

Shao, Yu; Wang, Ying; Cao, Shaoqing; Huang, Yijian; Zhang, Longfei; Zhang, Feng; Liao, Changrui; Wang, Yiping

2018-06-25

A surface plasmon resonance (SPR) sensor based on a side-polished single mode fiber coated with polyvinyl alcohol (PVA) is demonstrated for relative humidity (RH) sensing. The SPR sensor exhibits a resonant dip in the transmission spectrum in ambient air after PVA film coating, and the resonant wavelength shifts to longer wavelengths as the thickness of the PVA film increases. When RH changes, the resonant dip of the sensor with different film-thicknesses exhibits interesting characteristics for optical spectrum evolution. For sensors with initial wavelengths between 550 nm and 750 nm, the resonant dip shifts to longer wavelengths with increasing RH. The averaged sensitivity increases firstly and then drops, and shows a maximal sensitivity of 1.01 nm/RH%. Once the initial wavelength of the SPR sensor exceeds 850 nm, an inflection point of the resonant wavelength shift can be observed with RH increasing, and the resonant dip shifts to shorter wavelengths for RH values exceeding this point, and sensitivity as high as −4.97 nm/RH% can be obtained in the experiment. The sensor is expected to have potential applications in highly sensitive and cost effective humidity sensing.

Patients' views on changes in doctor-patient communication between 1982 and 2001: a mixed-methods study.

PubMed

Butalid, Ligaya; Verhaak, Peter F M; Boeije, Hennie R; Bensing, Jozien M

2012-08-08

Doctor-patient communication has been influenced over time by factors such as the rise of evidence-based medicine and a growing emphasis on patient-centred care. Despite disputes in the literature on the tension between evidence-based medicine and patient-centered medicine, patients' views on what constitutes high quality of doctor-patient communication are seldom an explicit topic for research. The aim of this study is to examine whether analogue patients (lay people judging videotaped consultations) perceive shifts in the quality of doctor-patient communication over a twenty-year period. Analogue patients (N = 108) assessed 189 videotaped general practice consultations from two periods (1982-1984 and 2000-2001). They provided ratings on three dimensions (scale 1-10) and gave written feedback. With a mixed-methods research design, we examined these assessments quantitatively (in relation to observed communication coded with RIAS) and qualitatively. 1) The quantitative analyses showed that biomedical communication and rapport building were positively associated with the quality assessments of videotaped consultations from the first period, but not from the second. Psychosocial communication and personal remarks were related to positive quality assessments of both periods; 2) the qualitative analyses showed that in both periods, participants provided the same balance between positive and negative comments. Listening, giving support, and showing respect were considered equally important in both periods. We identified shifts in the participants' observations on how GPs explained things to the patient, the division of roles and responsibilities, and the emphasis on problem-focused communication (first period) versus solution-focused communication (last period). Analogue patients recognize shifts in the quality of doctor-patient communication from two different periods, including a shift from problem-focused communication to solution-focused communication, and they value an egalitarian doctor-patient relationship. The two research methods were complementary; based on the quantitative analyses we found shifts in communication, which we confirmed and specified in our qualitative analyses.

Land Use Affects Carbon Sources to the Pelagic Food Web in a Small Boreal Lake

PubMed Central

Rinta, Päivi; van Hardenbroek, Maarten; Jones, Roger I.; Kankaala, Paula; Rey, Fabian; Szidat, Sönke; Wooller, Matthew J.; Heiri, Oliver

2016-01-01

Small humic forest lakes often have high contributions of methane-derived carbon in their food webs but little is known about the temporal stability of this carbon pathway and how it responds to environmental changes on longer time scales. We reconstructed past variations in the contribution of methanogenic carbon in the pelagic food web of a small boreal lake in Finland by analyzing the stable carbon isotopic composition (δ13C values) of chitinous fossils of planktivorous invertebrates in sediments from the lake. The δ13C values of zooplankton remains show several marked shifts (approx. 10 ‰), consistent with changes in the proportional contribution of carbon from methane-oxidizing bacteria in zooplankton diets. The results indicate that the lake only recently (1950s) obtained its present state with a high contribution of methanogenic carbon to the pelagic food web. A comparison with historical and palaeobotanical evidence indicates that this most recent shift coincided with agricultural land-use changes and forestation of the lake catchment and implies that earlier shifts may also have been related to changes in forest and land use. Our study demonstrates the sensitivity of the carbon cycle in small forest lakes to external forcing and that the effects of past changes in local land use on lacustrine carbon cycling have to be taken into account when defining environmental and ecological reference conditions in boreal headwater lakes. PMID:27487044

Rationalising pKa shifts in Bacillus circulans xylanase with computational studies.

PubMed

Xiao, Kela; Yu, Haibo

2016-11-09

Bacillus circulans xylanase (BcX), a family 11 glycoside hydrolase, catalyses the hydrolysis of xylose polymers with a net retention of stereochemistry. Glu172 in BcX is believed to act as a general acid by protonating the aglycone during glycosylation, and then as a general base to facilitate the deglycosylation step. The key to the dual role of this general acid/base lies in its protonation states, which depend on its intrinsic pK a value and the specific environment which it resides within. To fully understand the detailed molecular features in BcX to establish the dual role of Glu172, we present a combined study based on both atomistic simulations and empirical models to calculate pK a shifts for the general acid/base Glu172 in BcX at different functional states. Its pK a values and those of nearby residues, obtained based on QM/MM free energy calculations, MCCE and PROPKA, show a good agreement with available experimental data. Additionally, our study provides additional insights into the effects of structural and electrostatic perturbations caused by mutations and chemical modifications, suggesting that the local solvation environment and mutagenesis of the residues adjacent to Glu172 establish its dual role during hydrolysis. The strengths and limitations of various methods for calculating pK a s and pK a shifts have also been discussed.

Comparison of the substituent effects on the (13) C NMR with the (1) H NMR chemical shifts of CH=N in substituted benzylideneanilines.

PubMed

Wang, Linyan; Cao, Chaotun; Cao, Chenzhong

2015-07-01

Fifty-two samples of substituted benzylideneanilines XPhCH=NPhYs (XBAYs) were synthesized, and their NMR spectra were determined in this paper. Together with the NMR data of other 77 samples of XBAYs quoted from literatures, the (1) H NMR chemical shifts (δH (CH=N)) and (13) C NMR chemical shifts (δC (CH=N)) of the CH=N bridging group were investigated for total of 129 samples of XBAYs. The result shows that the δH (CH=N) and δC (CH=N) have no distinctive linear relationship, which is contrary to the theoretical thought that declared the δH (CH=N) values would increase as the δC (CH=N) values increase. With the in-depth analysis, we found that the effects of σF and σR of X/Y group on the δH (CH=N) and the δC (CH=N) are opposite; the effects of the substituent specific cross-interaction effect between X and Y (Δσ(2) ) on the δH (CH=N) and the δC (CH=N) are different; the contributions of parameters in the regression equations of the δH (CH=N) and the δC (CH=N) [Eqns and 7), respectively] also have an obvious difference. Copyright © 2015 John Wiley & Sons, Ltd.

Applying a Dynamic Stomatal Optimization to Predict Shifts in the Functional Composition of Tropical Forests Under Increased Drought And CO2

NASA Astrophysics Data System (ADS)

Bartlett, M. K.; Detto, M.; Pacala, S. W.

2017-12-01

The accurate prediction of tropical forest carbon fluxes is key to forecasting global climate, but forest responses to projected increases in CO2 and drought are highly uncertain. Here we present a dynamic optimization that derives the trajectory of stomatal conductance (gs) during drought, a key source of model uncertainty, from plant and soil water relations and the carbon economy of the plant hydraulic system. This optimization scheme is novel in two ways. First, by accounting for the ability of capacitance (i.e., the release of water from plant storage tissue; C) to buffer evaporative water loss and maintain gs during drought, this optimization captures both drought tolerant and avoidant hydraulic strategies. Second, by determining the optimal trajectory of plant and soil water potentials, this optimization quantifies species' impacts on the water available to competing plants. These advances allowed us to apply this optimization across the range of physiology trait values observed in tropical species to evaluate shifts in the competitively optimal trait values, or evolutionarily stable hydraulic strategy (ESS), under increased drought and CO2. Increasing the length of the dry season shifted the ESS towards more drought tolerant, rather than avoidant, trait values, and these shifts were larger for longer individual drought periods (i.e., more consecutive days without rainfall), even if the total time spent in drought was the same. Concurrently doubling the CO2 level reduced the magnitude of these shifts and slightly favored drought avoidant strategies under wet conditions. Overall, these analyses predicted that short, frequent droughts would allow elevated CO2 to shift the functional composition in tropical forests towards more drought avoidant species, while infrequent but long drought periods would shift the ESS to more drought tolerant trait values, despite increased CO2. Overall, these analyses quantified the impact of physiology traits on plant performance and competitive ability, and provide a mechanistic, trait-based approach to predict shifts in the functional composition of tropical forests under projected climatic conditions.

Body weight manipulation, reinforcement value and choice between sucrose and wheel running: a behavioral economic analysis.

PubMed

Belke, Terry W; Pierce, W David

2009-02-01

Twelve female Long-Evans rats were exposed to concurrent variable (VR) ratio schedules of sucrose and wheel-running reinforcement (Sucrose VR 10 Wheel VR 10; Sucrose VR 5 Wheel VR 20; Sucrose VR 20 Wheel VR 5) with predetermined budgets (number of responses). The allocation of lever pressing to the sucrose and wheel-running alternatives was assessed at high and low body weights. Results showed that wheel-running rate and lever-pressing rates for sucrose and wheel running increased, but the choice of wheel running decreased at the low body weight. A regression analysis of relative consumption as a function of relative price showed that consumption shifted toward sucrose and interacted with price differences in a manner consistent with increased substitutability. Demand curves showed that demand for sucrose became less elastic while demand for wheel running became more elastic at the low body weight. These findings reflect an increase in the difference in relative value of sucrose and wheel running as body weight decreased. Discussion focuses on the limitations of response rates as measures of reinforcement value. In addition, we address the commonalities between matching and demand curve equations for the analysis of changes in relative reinforcement value.

Neural representation of expected value in the adolescent brain.

PubMed

Barkley-Levenson, Emily; Galván, Adriana

2014-01-28

Previous work shows that the adolescent reward system is hyperactive, but this finding may be confounded by differences in how teens value money. To address this, we examined the neural ontogeny of objective value representation. Adolescent and adult participants performed a monetary gambling task in which they chose to accept or reject gambles of varying expected value. Increasing expected value had a stronger influence over gambling choices in adolescents relative to adults, an effect that was paralleled by greater activation in the ventral striatum in adolescents. This unique adolescent ventral striatum response remained even after matching groups on acceptance behavior. These behavioral and neural data suggest that the value of available options has a greater influence in adolescent versus adult choices, even when objective value and subjective choice are held constant. This research provides further evidence that hyperactivation of reward circuitry in adolescence may be a normative ontogenetic shift that is due to greater valuation in the adolescent brain.

Neural representation of expected value in the adolescent brain

PubMed Central

Barkley-Levenson, Emily; Galván, Adriana

2014-01-01

Previous work shows that the adolescent reward system is hyperactive, but this finding may be confounded by differences in how teens value money. To address this, we examined the neural ontogeny of objective value representation. Adolescent and adult participants performed a monetary gambling task in which they chose to accept or reject gambles of varying expected value. Increasing expected value had a stronger influence over gambling choices in adolescents relative to adults, an effect that was paralleled by greater activation in the ventral striatum in adolescents. This unique adolescent ventral striatum response remained even after matching groups on acceptance behavior. These behavioral and neural data suggest that the value of available options has a greater influence in adolescent versus adult choices, even when objective value and subjective choice are held constant. This research provides further evidence that hyperactivation of reward circuitry in adolescence may be a normative ontogenetic shift that is due to greater valuation in the adolescent brain. PMID:24474790

White matter tracts associated with set-shifting in healthy aging.

PubMed

Perry, Michele E; McDonald, Carrie R; Hagler, Donald J; Gharapetian, Lusineh; Kuperman, Joshua M; Koyama, Alain K; Dale, Anders M; McEvoy, Linda K

2009-11-01

Attentional set-shifting ability, commonly assessed with the Trail Making Test (TMT), decreases with increasing age in adults. Since set-shifting performance relies on activity in widespread brain regions, deterioration of the white matter tracts that connect these regions may underlie the age-related decrease in performance. We used an automated fiber tracking method to investigate the relationship between white matter integrity in several cortical association tracts and TMT performance in a sample of 24 healthy adults, 21-80 years. Diffusion tensor images were used to compute average fractional anisotropy (FA) for five cortical association tracts, the corpus callosum (CC), and the corticospinal tract (CST), which served as a control. Results showed that advancing age was associated with declines in set-shifting performance and with decreased FA in the CC and in association tracts that connect frontal cortex to more posterior brain regions, including the inferior fronto-occipital fasciculus (IFOF), uncinate fasciculus (UF), and superior longitudinal fasciculus (SLF). Declines in average FA in these tracts, and in average FA of the right inferior longitudinal fasciculus (ILF), were associated with increased time to completion on the set-shifting subtask of the TMT but not with the simple sequencing subtask. FA values in these tracts were strong mediators of the effect of age on set-shifting performance. Automated tractography methods can enhance our understanding of the fiber systems involved in performance of specific cognitive tasks and of the functional consequences of age-related changes in those systems.

Computerized clinical documentation system in the pediatric intensive care unit

PubMed Central

2001-01-01

Background To determine whether a computerized clinical documentation system (CDS): 1) decreased time spent charting and increased time spent in patient care; 2) decreased medication errors; 3) improved clinical decision making; 4) improved quality of documentation; and/or 5) improved shift to shift nursing continuity. Methods Before and after implementation of CDS, a time study involving nursing care, medication delivery, and normalization of serum calcium and potassium values was performed. In addition, an evaluation of completeness of documentation and a clinician survey of shift to shift reporting were also completed. This was a modified one group, pretest-posttest design. Results With the CDS there was: improved legibility and completeness of documentation, data with better accessibility and accuracy, no change in time spent in direct patient care or charting by nursing staff. Incidental observations from the study included improved management functions of our nurse manager; improved JCAHO documentation compliance; timely access to clinical data (labs, vitals, etc); a decrease in time and resource use for audits; improved reimbursement because of the ability to reconstruct lost charts; limited human data entry by automatic data logging; eliminated costs of printing forms. CDS cost was reasonable. Conclusions When compared to a paper chart, the CDS provided a more legible, compete, and accessible patient record without affecting time spent in direct patient care. The availability of the CDS improved shift to shift reporting. Other observations showed that the CDS improved management capabilities; helped physicians deliver care; improved reimbursement; limited data entry errors; and reduced costs. PMID:11604105

Early dynamics of the semantic priming shift

PubMed Central

Lavigne, Frédéric; Chanquoy, Lucile; Dumercy, Laurent; Vitu, Françoise

2013-01-01

Semantic processing of sequences of words requires the cognitive system to keep several word meanings simultaneously activated in working memory with limited capacity. The real- time updating of the sequence of word meanings relies on dynamic changes in the associates to the words that are activated. Protocols involving two sequential primes report a semantic priming shift from larger priming of associates to the first prime to larger priming of associates to the second prime, in a range of long SOAs (stimulus-onset asynchronies) between the second prime and the target. However, the possibility for an early semantic priming shift is still to be tested, and its dynamics as a function of association strength remain unknown. Three multiple priming experiments are proposed that cross-manipulate association strength between each of two successive primes and a target, for different values of short SOAs and prime durations. Results show an early priming shift ranging from priming of associates to the first prime only to priming of strong associates to the first prime and all of the associates to the second prime. We investigated the neural basis of the early priming shift by using a network model of spike frequency adaptive cortical neurons (e.g., Deco & Rolls, 2005), able to code different association strengths between the primes and the target. The cortical network model provides a description of the early dynamics of the priming shift in terms of pro-active and retro-active interferences within populations of excitatory neurons regulated by fast and unselective inhibitory feedback. PMID:23717346

Bandgap Shifting of an Ultra-Thin InGaAs/InP Quantum Well Infrared Photodetector

NASA Technical Reports Server (NTRS)

Sengupta, D. K.; Gunapala, S. D.; Bandara, S. V.; Liu, J. K.; Luong, E.; Hong, W.; Mumolo, J.; Bae, Y.; Stillman, G. E.; Jackson, S. L.;

Research and development for a ground-based hydrogen-maser system

NASA Technical Reports Server (NTRS)

1972-01-01

The results of a joint experiment aimed primarily at the determination of the frequency of the H(1) hyperfine transition are reported. The transition frequency value for Cs-133 hyperfine transition is found. The result is the mean of two independent evaluations against the cesium reference, which differ by 0.002 Hz. The one-sigma uncertainty of the value nu sub H is also estimated to be 0.002 Hz. One evaluation is based on wall shift experiments at Harvard University; the other is a result of new wall shift measurement using many storage bulbs of different sizes at the National Bureau of Standards. The experimental procedures and the applied corrections are described. Results for the wall shift and for the frequency of hydrogen are compared with previously published values, and error limits of the experiments are discussed.

Characteristics and issues of an EUVL mask applying phase-shifting thinner absorber for device fabrication

NASA Astrophysics Data System (ADS)

Seo, Hwan-Seok; Lee, Dong-Gun; Ahn, Byung-Sup; Han, Hakseung; Huh, Sungmin; Kang, In-Yong; Kim, Hoon; Kim, Dongwan; Kim, Seong-Sue; Cho, Han-Ku

2009-03-01

Phase-shifting EUVL masks applying thinner absorber are investigated to design optimum mask structure with less shadowing problems. Simulations using S-Litho show that H-V bias in Si capping structure is higher than that of Ru capping since the high n (= 0.999) of Si increases sensible absorber height. Phase differences obtained from the patterned masks using the EUV CSM are well-matched with the calculated values using the practical refractive index of absorber materials. Although the mask with 62.4-nm-thick absorber, among the in-house masks, shows the closest phase ΔΦ(= 176°) to the out-of-phase condition, higher NILS and contrast as well as lower H-V bias are obtained with 52.4-nm-thick absorber (ΔΦ = 151°) which has higher R/R0 ratio. MET results also show that lithography performances including MEEF, PW, and resist threshold (dose), are improved with thinner absorber structure. However, low OD in EUVL mask, especially in thinner absorber structure, results in light leakage from the neighboring exposure shots, and thus an appropriate light-shielding layer should be introduced.

Comment on linewidths and shifts in the Stokes-Raman Q branch of D2 in He

NASA Technical Reports Server (NTRS)

Green, Sheldon; Blackmore, Robert; Monchick, Louis

1989-01-01

Collision-induced widths and shifts for Raman Q-branch transitions of D2 in He were calculated from S matrices obtained with converged close coupling scattering calculations on an accurate theoretical interaction potential. Results agree well with experimental values. Discrepancies between experimental line shifts and theoretical values from an earlier study (Blackmore et al., 1988) are traced to a computational error in that work. The effects of vibrational inelasticity and of centrifugal distortion on energy levels and on potential matrix elements, all of which were ignored in the earlier study, are explicitly considered here and found to be small.

Application of ChemDraw NMR Tool: Correlation of Program-Generated 13C Chemical Shifts and pKa Values of para-Substituted Benzoic Acids

NASA Astrophysics Data System (ADS)

Wang, Hongyi

2005-09-01

An application of ChemDraw NMR Tool was demonstrated by correlation of program-generated 13 C NMR chemical shifts and p K a values of para-substituted benzoic acids. Experimental 13 C NMR chemical shifts were analyzed in the same way for comparison. The project can be used as an assignment at the end of the first-year organic chemistry course to review topics or explore new techniques: Hammett equation, acid base equilibrium theory, electronic nature of functional groups, inductive and resonance effects, structure reactivity relationship, NMR spectroscopy, literature search, database search, and ChemDraw software.

Evidence of shift in C4 species range in central Argentina during the late Holocene

USGS Publications Warehouse

Silva, L.C.R.; Giorgis, M.A.; Anand, M.; Enrico, L.; Perez-Harguindeguy, N.; Falczuk, V.; Tieszen, L.L.; Cabido, M.

2011-01-01

AimMillennial-scale biogeographic changes are well understood in many parts of the world, but little is known about long-term vegetation dynamics in subtropical regions. Here we investigate shifts in C3/C4 plant abundance occurred in central Argentina during the past few millenniaMethodsWe determined present day soil organic matter δ13C signatures of grasslands, shrublands and woodlands, containing different mixtures of C3 and C4 plants. We measured past changes in the relative cover of C3/C4 plants by comparing δ13C values in soil profiles with present day δ13C signatures. We analyzed 14C activity in soil depths that showed major changes in vegetation.ResultsPresent day relative cover of C3/C4 plants determines whole ecosystem δ13C signatures integrated as litter and superficial soil organic matter (R2 = 0.78; p < 0.01). Deeper soils show a consistent shift in δ13C, indicating a continuous replacement of C4 by C3 plants since 3,870 (±210) YBP. During this period, the relative abundance of C3 plants increased 32% (average across sites) with significant changes being observed in all studied ecosystems.ConclusionsOur results show that C4 species were more abundant in the past, but C3 species became dominant during the late Holocene. We identified increases in the relative C3/C4 cover in grasslands, shrublands and woodlands, suggesting a physiological basis for changes in vegetation. The replacement of C4 by C3 plants coincided with changes in climate towards colder and wetter conditions and could represent a climatically driven shift in the C4 species optimum range.

Orbital angular momentum (OAM) spectrum correction in free space optical communication.

PubMed

Liu, Yi-Dong; Gao, Chunqing; Qi, Xiaoqing; Weber, Horst

2008-05-12

Orbital angular momentum (OAM) of laser beams has potential application in free space optical communication, but it is sensitive against pointing instabilities of the beam, i.e. shift (lateral displacement) and tilt (deflection of the beam). This work proposes a method to correct the distorted OAM spectrum by using the mean square value of the orbital angular momentum as an indicator. Qualitative analysis is given, and the numerical simulation is carried out for demonstration. The results show that the mean square value can be used to determine the beam axis of the superimposed helical beams. The initial OAM spectrum can be recovered.

Nanohardness and Residual Stress in TiN Coatings.

PubMed

Hernández, Luis Carlos; Ponce, Luis; Fundora, Abel; López, Enrique; Pérez, Eduardo

2011-05-17

TiN films were prepared by the Cathodic arc evaporation deposition method under different negative substrate bias. AFM image analyses show that the growth mode of biased coatings changes from 3D island to lateral when the negative bias potential is increased. Nanohardness of the thin films was measured by nanoindentation, and residual stress was determined using Grazing incidence X ray diffraction. The maximum value of residual stress is reached at -100 V substrate bias coinciding with the biggest values of adhesion and nanohardness. Nanoindentation measurement proves that the force-depth curve shifts due to residual stress. The experimental results demonstrate that nanohardness is seriously affected by the residual stress.

Density functional calculations of the Mössbauer parameters in hexagonal ferrite SrFe12O19

NASA Astrophysics Data System (ADS)

Ikeno, Hidekazu

2018-03-01

Mössbauer parameters in a magnetoplumbite-type hexagonal ferrite, SrFe12O19, are computed using the all-electron band structure calculation based on the density functional theory. The theoretical isomer shift and quadrupole splitting are consistent with experimentally obtained values. The absolute values of hyperfine splitting parameters are found to be underestimated, but the relative scale can be reproduced. The present results validate the site-dependence of Mössbauer parameters obtained by analyzing experimental spectra of hexagonal ferrites. The results also show the usefulness of theoretical calculations for increasing the reliability of interpretation of the Mössbauer spectra.

Covalent character and electric field dependence of H2-AgX (X = F - I).

PubMed

Li, Xinying

2018-06-16

Mechanisms of Ag-X and Ag…H 2 interactions and stabilities of T-shaped H 2 -AgX (X = F - I) series were investigated at the CCSD(T) level. The "no-density" bond with smaller positive Laplacian and ELF values in interaction regions, as well as considerable delocalization index values, suggest weak covalent "charge-shift" character for the Ag…H 2 interaction. Structure and stability dependence on the electric field were investigated at the MP2 level. Relative total energy curves show obvious parabolic character, and the plots can be fitted by quadratic polynomials as functions of electric field strength.

A shift in anterior–posterior positional information underlies the fin-to-limb evolution

PubMed Central

Onimaru, Koh; Kuraku, Shigehiro; Takagi, Wataru; Hyodo, Susumu; Sharpe, James; Tanaka, Mikiko

2015-01-01

The pectoral fins of ancestral fishes had multiple proximal elements connected to their pectoral girdles. During the fin-to-limb transition, anterior proximal elements were lost and only the most posterior one remained as the humerus. Thus, we hypothesised that an evolutionary alteration occurred in the anterior–posterior (AP) patterning system of limb buds. In this study, we examined the pectoral fin development of catshark (Scyliorhinus canicula) and revealed that the AP positional values in fin buds are shifted more posteriorly than mouse limb buds. Furthermore, examination of Gli3 function and regulation shows that catshark fins lack a specific AP patterning mechanism, which restricts its expression to an anterior domain in tetrapods. Finally, experimental perturbation of AP patterning in catshark fin buds results in an expansion of posterior values and loss of anterior skeletal elements. Together, these results suggest that a key genetic event of the fin-to-limb transformation was alteration of the AP patterning network. DOI: http://dx.doi.org/10.7554/eLife.07048.001 PMID:26283004

DFT calculations on spectroscopic and structural properties of a NLO chromophore

NASA Astrophysics Data System (ADS)

Altürk, Sümeyye; Avci, Davut; Tamer, Ömer; Atalay, Yusuf

2016-03-01

The molecular geometry optimization, vibrational frequencies and gauge including atomic orbital (GIAO) 1H and 13C NMR chemical shift values of 2-(1'-(4'''-Methoxyphenyl)-5'-(thien-2″-yl)pyrrol-2'-yl)-1,3-benzothiazole as potential nonlinear optical (NLO) material were calculated using density functional theory (DFT) HSEh1PBE method with 6-311G(d,p) basis set. The best of our knowledge, this study have not been reported to date. Additionally, a detailed vibrational study was performed on the basis of potential energy distribution (PED) using VEDA program. It is noteworthy that NMR chemical shifts are quite useful for understanding the relationship between the molecular structure and electronic properties of molecules. The computed IR and NMR spectra were used to determine the types of the experimental bands observed. Predicted values of structural and spectroscopic parameters of the chromophore were compared with each other so as to display the effects of the different substituents on the spectroscopic and structural properties. Obtained data showed that there is an agreement between the predicted and experimental data.

Macroion induced dehydration of weak polyelectrolyte brushes

NASA Astrophysics Data System (ADS)

Zheng, Zhongli; Zhu, Y. Elaine

2014-03-01

The interaction of macroions, including polyelectrolytes, DNAs, and proteins, with polymer and cellular surfaces is critically related to many biomolecular activities, such as protein adsorption and DNA hybridization at probe surfaces. In an experimental approach to examine the macroion electrostatic interaction with a polymer surface while minimizing the long-debated hydrophobic interaction, we study the interaction of molybdenum-based inorganic polyoxometalate (POM) nanoclusters carrying 42 negative charges as model hydrophilic macroions with surface-tethered poly-2-vinylpyridine (P2VP) brushes immersed in aqueous solutions. By AFM, QCM, and contact goniometer, we have observed the collapse of P2VP chains by adding POM macroions at a constant pH. Surprisingly, added POM macroions can cause the shift of swollen-to-collapse transition pH to a lower value, in contrast to the shift to high pH value by adding simple monovalent salts. At sufficiently high POM concentration, a stable POM-P2VP composite layer, showing little dependence on solution pH and additional salts, can be formed, suggesting a simple route to construct meso-porous polymer membranes.

High-performance magnetic field sensor based on superconducting quantum interference filters

NASA Astrophysics Data System (ADS)

Caputo, P.; Oppenländer, J.; Häussler, Ch.; Tomes, J.; Friesch, A.; Träuble, T.; Schopohl, N.

2004-08-01

We have developed an absolute magnetic field sensor using a superconducting quantum interference filter (SQIF) made of high-Tc grain-boundary Josephson junctions. The device shows the typical magnetic-field-dependent voltage response V(B ), which is a sharp deltalike dip in the vicinity of zero-magnetic field. When the SQIF is cooled with magnetic shield, and then the shield is removed, the presence of the ambient magnetic field induces a shift of the dip position from B0≈0 to a value B ≈B1, which is about the average value of the Earth's magnetic field, at our latitude. When the SQIF is cooled in the ambient field without shielding, the dip is first found at B ≈B1, and the further shielding of the SQIF results in a shift of the dip towards B0≈0. The low hysteresis observed in the sequence of experiments (less than 5% of B1) makes SQIFs suitable for high precision measurements of the absolute magnetic field. The experimental results are discussed in view of potential applications of high-Tc SQIFs in magnetometry.

Synthesis and photophysical properties of aluminium tris-(4-morpholine-8-hydroxyquinoline).

PubMed

Omar, Walaa A E

2013-11-01

Aluminium tris(4-morpholinyl-8-hydroxyquinoline) has been synthesized and characterized. The photoluminescence measurements showed that the new derivative is blue shifted and has relative photoluminescence quantum yield two times higher compared to the pristine Al tris(8-hydroxyquinoline). Deferential scanning colorimetric studies revealed that the newly synthesized Alq3 derivative in this work is amorphous material with the highest transition glass temperature value among the reported amorphous Alq3 derivatives.

Volume shift and charge instability of simple-metal clusters

NASA Astrophysics Data System (ADS)

Brajczewska, M.; Vieira, A.; Fiolhais, C.; Perdew, J. P.

1996-12-01

Experiment indicates that small clusters show changes (mostly contractions) of the bond lengths with respect to bulk values. We use the stabilized jellium model to study the self-expansion and self-compression of spherical clusters (neutral or ionized) of simple metals. Results from Kohn - Sham density functional theory are presented for small clusters of Al and Na, including negatively-charged ones. We also examine the stability of clusters with respect to charging.

Bias voltage dependence of the electron spin depolarization in quantum wires in the quantum Hall regime detected by the resistively detected NMR

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

Chida, K.; Yamauchi, Y.; Arakawa, T.

2013-12-04

We performed the resistively-detected nuclear magnetic resonance (RDNMR) to study the electron spin polarization in the non-equilibrium quantum Hall regime. By measuring the Knight shift, we derive source-drain bias voltage dependence of the electron spin polarization in quantum wires. The electron spin polarization shows minimum value around the threshold voltage of the dynamic nuclear polarization.

Disentangling the f(R)-duality

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

Broy, Benedict J.; Pedro, Francisco G.; Westphal, Alexander

2015-03-16

Motivated by UV realisations of Starobinsky-like inflation models, we study generic exponential plateau-like potentials to understand whether an exact f(R)-formulation may still be obtained when the asymptotic shift-symmetry of the potential is broken for larger field values. Potentials which break the shift symmetry with rising exponentials at large field values only allow for corresponding f(R)-descriptions with a leading order term R{sup n} with 1

Disentangling the f(R)-duality

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

Broy, Benedict J.; Westphal, Alexander; Pedro, Francisco G., E-mail: benedict.broy@desy.de, E-mail: francisco.pedro@desy.de, E-mail: alexander.westphal@desy.de

2015-03-01

Motivated by UV realisations of Starobinsky-like inflation models, we study generic exponential plateau-like potentials to understand whether an exact f(R)-formulation may still be obtained when the asymptotic shift-symmetry of the potential is broken for larger field values. Potentials which break the shift symmetry with rising exponentials at large field values only allow for corresponding f(R)-descriptions with a leading order term R{sup n} with 1

Behavioural and neural modulation of win-stay but not lose-shift strategies as a function of outcome value in Rock, Paper, Scissors.

PubMed

Forder, Lewis; Dyson, Benjamin James

2016-09-23

Competitive environments in which individuals compete for mutually-exclusive outcomes require rational decision making in order to maximize gains but often result in poor quality heuristics. Reasons for the greater reliance on lose-shift relative to win-stay behaviour shown in previous studies were explored using the game of Rock, Paper, Scissors and by manipulating the value of winning and losing. Decision-making following a loss was characterized as relatively fast and relatively inflexible both in terms of the failure to modulate the magnitude of lose-shift strategy and the lack of significant neural modulation. In contrast, decision-making following a win was characterized as relatively slow and relatively flexible both in terms of a behavioural increase in the magnitude of win-stay strategy and a neural modulation of feedback-related negativity (FRN) and stimulus-preceding negativity (SPN) following outcome value modulation. The win-stay/lose-shift heuristic appears not to be a unified mechanism, with the former relying on System 2 processes and the latter relying on System 1 processes. Our ability to play rationally appears more likely when the outcome is positive and when the value of wins are low, highlighting how vulnerable we can be when trying to succeed during competition.

Host Plant Physiology and Mycorrhizal Functioning Shift across a Glacial through Future [CO2] Gradient.

PubMed

Becklin, Katie M; Mullinix, George W R; Ward, Joy K

2016-10-01

Rising atmospheric carbon dioxide concentration ([CO 2 ]) may modulate the functioning of mycorrhizal associations by altering the relative degree of nutrient and carbohydrate limitations in plants. To test this, we grew Taraxacum ceratophorum and Taraxacum officinale (native and exotic dandelions) with and without mycorrhizal fungi across a broad [CO 2 ] gradient (180-1,000 µL L -1 ). Differential plant growth rates and vegetative plasticity were hypothesized to drive species-specific responses to [CO 2 ] and arbuscular mycorrhizal fungi. To evaluate [CO 2 ] effects on mycorrhizal functioning, we calculated response ratios based on the relative biomass of mycorrhizal (M Bio ) and nonmycorrhizal (NM Bio ) plants (R Bio = [M Bio - NM Bio ]/NM Bio ). We then assessed linkages between R Bio and host physiology, fungal growth, and biomass allocation using structural equation modeling. For T. officinale, R Bio increased with rising [CO 2 ], shifting from negative to positive values at 700 µL L -1 [CO 2 ] and mycorrhizal effects on photosynthesis and leaf growth rates drove shifts in R Bio in this species. For T. ceratophorum, R Bio increased from 180 to 390 µL L -1 and further increases in [CO 2 ] caused R Bio to shift from positive to negative values. [CO 2 ] and fungal effects on plant growth and carbon sink strength were correlated with shifts in R Bio in this species. Overall, we show that rising [CO 2 ] significantly altered the functioning of mycorrhizal associations. These symbioses became more beneficial with rising [CO 2 ], but nonlinear effects may limit plant responses to mycorrhizal fungi under future [CO 2 ]. The magnitude and mechanisms driving mycorrhizal-CO 2 responses reflected species-specific differences in growth rate and vegetative plasticity, indicating that these traits may provide a framework for predicting mycorrhizal responses to global change. © 2016 American Society of Plant Biologists. All Rights Reserved.

Regional and temporal variability of the isotope composition (O, S) of atmospheric sulphate in the region of Freiberg, Germany, and consequences for dissolved sulphate in groundwater and river water.

PubMed

Tichomirowa, Marion; Heidel, Claudia

2012-01-01

The isotope composition of dissolved sulphate and strontium in atmospheric deposition, groundwater, mine water and river water in the region of Freiberg was investigated to better understand the fate of these components in the regional and global water cycle. Most of the isotope variations of dissolved sulphates in atmospheric deposition from three locations sampled bi- or tri-monthly can be explained by fractionation processes leading to lower [Formula: see text] (of about 2-3‰) and higher [Formula: see text] (of about 8-10‰) values in summer compared with the winter period. These samples showed a negative correlation between [Formula: see text] and [Formula: see text] values and a weak positive correlation between [Formula: see text] and [Formula: see text] values. They reflect the sulphate formed by aqueous oxidation from long-range transport in clouds. However, these isotope variations were superimposed by changes of the dominating atmospheric sulphate source. At two of the sampling points, large variations of mean annual [Formula: see text] values from atmospheric bulk deposition were recorded. From 2008 to 2009, the mean annual [Formula: see text] value increased by about 5‰; and decreased by about 4‰ from 2009 to 2010. A change in the dominating sulphate source or oxidation pathways of SO(2) in the atmosphere is proposed to cause these shifts. No changes were found in corresponding [Formula: see text] values. Groundwater, river water and some mine waters (where groundwater was the dominating sulphate source) also showed temporal shifts in their [Formula: see text] values corresponding to those of bulk atmospheric deposition, albeit to a lower degree. The mean transit time of atmospheric sulphur through the soil into the groundwater and river water was less than a year and therefore much shorter than previously suggested. Mining activities of about 800 years in the Freiberg region may have led to large subsurface areas with an enhanced groundwater flow along fractures and mined-refilled ore lodes which may shorten transit times of sulphate from precipitation through groundwater into river water.

Values: the dynamic nexus between biology, ecology and culture.

PubMed

Fischer, Ronald; Boer, Diana

2016-04-01

Values are motivational goals that influence attitudes, behaviors and evaluations. Cross-cultural evidence suggests that values show a systematic structure. Personal and cultural variations in the value structure, value priorities and value links to attitudes, behavior and well-being reflect contextual constraints and affordances in the environment, suggesting that values function as broadly adaptive psychological structures. The internal structure of values (the descriptive value system) becomes more clearly differentiated in more economically developed contexts. Value priorities shift toward more autonomous, self-expressive and individualistic orientations with greater economic resources and less ecological stress. In addition to systematic changes in internal structure, value links to attitudes, behaviors and well-being are influenced by economic, ecological and institutional contexts. Values are more likely to be expressed in attitudes and behavior if individuals have greater access to economic resources, experience less institutional and ecological stress or when the values reinforce culturally normative behavior. Frontiers for further value research include a greater examination of the neural underpinnings of values in specific ecological contexts and across the lifespan; and an examination of how values are behaviorally instantiated in different environments. Copyright © 2015 Elsevier Ltd. All rights reserved.

Optimization Photodetectors from Zinc Sulfide Deposited on Porous Silicon with Different Doping Metals

NASA Astrophysics Data System (ADS)

Nayef, Uday Muhsin; Khalaf, Haider Amer

In this work, the structural properties of the zinc sulfide (ZnS) films have been investigated using X-ray diffraction (XRD) analysis which show an enhancement in the crystallite degree after doping with copper (Cu). Good matching between the ZnS and porous silicon (PS) structure was noted from the atomic force microscope (AFM) results. The reflectivity gave a clear observation of anti-reflected coating improvement for PS layer and more enhancements after the ZnS deposition. The optical properties show a blue shift in the bandgap for the ZnS deposited with higher substrate temperature and a red shift after doped with different elements. For ZnS/PS heterojunction, the electrical resistivity has been increased after PS layer formed and changed with the variation of the pore size and it was much higher after ZnS deposited on the PS. However, use of ZnS:Cu/PS photodetector showed much higher output current at the ultraviolet (UV) region compared to ZnS/PS. The ZnS:Cu/PS photodetector showed higher output current value than that of the ZnS/PS leading to improvement in the quantum efficiency of 42%.

Accuracy of various impression materials and methods for two implant systems: An effect size study.

PubMed

Schmidt, Alexander; Häussling, Teresa; Rehmann, Peter; Schaaf, Heidrun; Wöstmann, Bernd

2018-04-01

An accurate impression is required for implant treatment. The aim of this in-vitro study was to determine the effect size of the impression material/method, implant system and implant angulation on impression transfer precision. An upper jaw model with three BEGO and three Straumann implants (angulations 0°, 15°, 20°) in the left and right maxilla was used as a reference model. One polyether (Impregum Penta) and two polyvinyl siloxanes (Flexitime Monophase/Aquasil Ultra Monophase) were examined with two impression techniques (open and closed tray). A total of 60 impressions were made. A coordinate measurement machine was used to measure the target variables for 3D-shift, implant axis inclination and implant axis rotation. All the data were subjected to a four-way ANOVA. The effect size (partial eta-squared [η 2 P ]) was reported. The impression material had a significant influence on the 3D shift and the implant axis inclination deviation (p-values=.000), and both factors had very large effect sizes (3D-shift [η 2 P ]=.599; implant axis inclination [η 2 P ]=.298). Impressions made with polyvinyl siloxane exhibited the highest transfer precision. When the angulation of the implants was larger, more deviations occurred for the implant axis rotational deviation. The implant systems and impression methods showed partially significant variations (p-values=.001-.639) but only very small effect sizes (η 2 P =.001-.031). The impression material had the greatest effect size on accuracy in terms of the 3D shift and the implant axis inclination. For multiunit restorations with disparallel implants, polyvinyl siloxane materials should be considered. In addition, the effect size of a multivariate investigation should be reported. Copyright © 2017 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

Measurement of the Membrane Dipole Electric Field in DMPC Vesicles Using Vibrational Shifts of p-Cyanophenylalanine and Molecular Dynamics Simulations

PubMed Central

Shrestha, Rebika; Cardenas, Alfredo E.; Elber, Ron; Webb, Lauren J.

2015-01-01

The magnitude of the membrane dipole field was measured using vibrational Stark effect (VSE) shifts of nitrile oscillators placed on the unnatural amino acid p-cyanophenylalanine (p-CN-Phe) added to a peptide sequence at four unique positions. These peptides, which were based on a repeating alanine-leucine motif, intercalated into small unilamellar DMPC vesicles which formed an α-helix as confirmed by circular dichroic (CD) spectroscopy. Molecular dynamics simulations of the membrane-intercalated helix containing two of the nitrile probes, one near the head-group region of the lipid (αLAX(25)) and one buried in the interior of the bilayer (αLAX(16)), were used to examine the structure of the nitrile with respect to the membrane normal, the assumed direction the dipole field, by quantifying both a small tilt of the helix in the bilayer and conformational rotation of the p-CN-Phe side chain at steady-state. Vibrational absorption energies of the nitrile oscillator at each position showed a systematic blue shift as the nitrile was stepped towards the membrane interior; for several different concentrations of peptide, the absorption energy of the nitrile located in the middle of the bilayer was ~3 cm−1 greater than that of the nitrile closest to the surface of the membrane. Taken together, the measured VSE shifts and nitrile orientations within the membrane resulted in a value of 8 – 11 MV/cm for the dipole field, at the high end of the range of possible values that have been accumulated from a variety of indirect measurements. Implications for this are discussed. PMID:25602635

Specific Contributions of Ventromedial, Anterior Cingulate, and Lateral Prefrontal Cortex for Attentional Selection and Stimulus Valuation

PubMed Central

Kaping, Daniel; Vinck, Martin; Hutchison, R. Matthew; Everling, Stefan; Womelsdorf, Thilo

2011-01-01

Attentional control ensures that neuronal processes prioritize the most relevant stimulus in a given environment. Controlling which stimulus is attended thus originates from neurons encoding the relevance of stimuli, i.e. their expected value, in hand with neurons encoding contextual information about stimulus locations, features, and rules that guide the conditional allocation of attention. Here, we examined how these distinct processes are encoded and integrated in macaque prefrontal cortex (PFC) by mapping their functional topographies at the time of attentional stimulus selection. We find confined clusters of neurons in ventromedial PFC (vmPFC) that predominantly convey stimulus valuation information during attention shifts. These valuation signals were topographically largely separated from neurons predicting the stimulus location to which attention covertly shifted, and which were evident across the complete medial-to-lateral extent of the PFC, encompassing anterior cingulate cortex (ACC), and lateral PFC (LPFC). LPFC responses showed particularly early-onset selectivity and primarily facilitated attention shifts to contralateral targets. Spatial selectivity within ACC was delayed and heterogeneous, with similar proportions of facilitated and suppressed responses during contralateral attention shifts. The integration of spatial and valuation signals about attentional target stimuli was observed in a confined cluster of neurons at the intersection of vmPFC, ACC, and LPFC. These results suggest that valuation processes reflecting stimulus-specific outcome predictions are recruited during covert attentional control. Value predictions and the spatial identification of attentional targets were conveyed by largely separate neuronal populations, but were integrated locally at the intersection of three major prefrontal areas, which may constitute a functional hub within the larger attentional control network. PMID:22215982

Striatal Activity and Reward Relativity: Neural Signals Encoding Dynamic Outcome Valuation

PubMed Central

Webber, Emily S.; Mankin, David E.

2016-01-01

Abstract The striatum is a key brain region involved in reward processing. Striatal activity has been linked to encoding reward magnitude and integrating diverse reward outcome information. Recent work has supported the involvement of striatum in the valuation of outcomes. The present work extends this idea by examining striatal activity during dynamic shifts in value that include different levels and directions of magnitude disparity. A novel task was used to produce diverse relative reward effects on a chain of instrumental action. Rats (Rattus norvegicus) were trained to respond to cues associated with specific outcomes varying by food pellet magnitude. Animals were exposed to single-outcome sessions followed by mixed-outcome sessions, and neural activity was compared among identical outcome trials from the different behavioral contexts. Results recording striatal activity show that neural responses to different task elements reflect incentive contrast as well as other relative effects that involve generalization between outcomes or possible influences of outcome variety. The activity that was most prevalent was linked to food consumption and post-food consumption periods. Relative encoding was sensitive to magnitude disparity. A within-session analysis showed strong contrast effects that were dependent upon the outcome received in the immediately preceding trial. Significantly higher numbers of responses were found in ventral striatum linked to relative outcome effects. Our results support the idea that relative value can incorporate diverse relationships, including comparisons from specific individual outcomes to general behavioral contexts. The striatum contains these diverse relative processes, possibly enabling both a higher information yield concerning value shifts and a greater behavioral flexibility. PMID:27822506

Striatal Activity and Reward Relativity: Neural Signals Encoding Dynamic Outcome Valuation.

PubMed

Webber, Emily S; Mankin, David E; Cromwell, Howard C

2016-01-01

The striatum is a key brain region involved in reward processing. Striatal activity has been linked to encoding reward magnitude and integrating diverse reward outcome information. Recent work has supported the involvement of striatum in the valuation of outcomes. The present work extends this idea by examining striatal activity during dynamic shifts in value that include different levels and directions of magnitude disparity. A novel task was used to produce diverse relative reward effects on a chain of instrumental action. Rats ( Rattus norvegicus ) were trained to respond to cues associated with specific outcomes varying by food pellet magnitude. Animals were exposed to single-outcome sessions followed by mixed-outcome sessions, and neural activity was compared among identical outcome trials from the different behavioral contexts. Results recording striatal activity show that neural responses to different task elements reflect incentive contrast as well as other relative effects that involve generalization between outcomes or possible influences of outcome variety. The activity that was most prevalent was linked to food consumption and post-food consumption periods. Relative encoding was sensitive to magnitude disparity. A within-session analysis showed strong contrast effects that were dependent upon the outcome received in the immediately preceding trial. Significantly higher numbers of responses were found in ventral striatum linked to relative outcome effects. Our results support the idea that relative value can incorporate diverse relationships, including comparisons from specific individual outcomes to general behavioral contexts. The striatum contains these diverse relative processes, possibly enabling both a higher information yield concerning value shifts and a greater behavioral flexibility.

ATP-induced current in isolated outer hair cells of guinea pig cochlea.

PubMed

Nakagawa, T; Akaike, N; Kimitsuki, T; Komune, S; Arima, T

1990-05-01

1. Electrical and pharmacologic properties of ATP-induced current in outer hair cells isolated from guinea pig cochlea were investigated in the whole-cell recording mode by the use of a conventional patch-clamp technique. 2. Under current-clamp conditions, rapid application of ATP depolarized the outer hair cells resulting in an increase in conductance. The ATP-induced response did not show any desensitization during a continuous application. 3. At a holding potential of -70 mV, the ATP-induced inward current increased in a sigmoidal fashion over the concentration range between 3 microM and 1 mM. The half-maximum concentration (EC50) was 12 microM and the Hill coefficient was 0.93. 4. The ATP-induced current had a reversal potential near 6 mV, which was close to the theoretical value (1 mV) calculated from the Goldman-Hodgkin-Katz equation for permeable intra- and extracellular cations. 5. In the current-voltage (I-V) relationship for the ATP response, a slight inward-going rectification was observed at more positive potentials than the reversal potential. 6. The substitution of extracellular Na+ by equimolar choline+ shifted the reversal potential of the ATP-induced current to more negative values. The substitution of Cs+ in the internal solution by N-methyl-D-glucamine+ (NMG+) shifted it in the positive direction. The reversal potential of ATP-induced current was also shifted to positive values with increasing extracellular Ca2+ concentration. A decrease of intracellular Cl- by gluconate- did not affect the reversal potential, thereby indicating that the ATP-induced current is carried through a large cation channel.(ABSTRACT TRUNCATED AT 250 WORDS)

Relevance of Urinary 3-Hydroxybenzo(a)pyrene and 1-Hydroxypyrene to Assess Exposure to Carcinogenic Polycyclic Aromatic Hydrocarbon Mixtures in Metallurgy Workers

PubMed Central

Barbeau, Damien; Persoons, Renaud; Marques, Marie; Hervé, Claire; Laffitte-Rigaud, Gilbert; Maitre, Anne

2014-01-01

Objectives: In metallurgy, workers are exposed to mixtures of polycyclic aromatic hydrocarbons (PAHs) in which some compounds are carcinogenic. Biomonitoring of PAH exposure has been performed by measuring urinary 1-hydroxypyrene (1-OHP), a metabolite of pyrene which is not carcinogenic. This study investigated the use of 3-hydroxybenzo(a)pyrene (3-OHBaP), a metabolite of benzo(a)pyrene (BaP) which is the main carcinogenic component in PAHs, to improve carcinogen exposure assessment. Methods: We included 129 metallurgy workers routinely exposed to PAHs during working hours. Urinary samples were collected at three sampling times at the beginning and at the end of the working week for 1-OHP and 3-OHBaP analyses. Results: Workers in anode production showed greater exposure to both biomarkers than those in cathode or silicon production, with respectively, 71, 40, and 30% of 3-OHBaP concentrations exceeding the value of 0.4 nmol mol−1 creatinine. No difference was observed between the 3-OHBaP levels found at the end of the penultimate workday shift and those at the beginning of the last workday shift. Within these plants, the 1-OHP/3-OHBaP ratios varied greatly according to the workers’ activity and emission sources. Using linear regression between these two metabolites, the 1-OHP level corresponding to the guidance value for 3-OHBaP ranged from 0.7 to 2.4 µmol mol−1 creatinine, depending on the industrial sector. Conclusions: This study emphasizes the interest of monitoring urinary 3-OHBaP at the end of the last workday shift when working week exposure is relatively steady, and the irrelevance of a single guideline value for 1-OHP when assessing occupational health risk. PMID:24504174

Variation in the isotopic composition of striped weakfish Cynoscion guatucupa of the Southwest Atlantic Ocean in response to dietary shifts.

PubMed

Viola, M N Paso; Riccialdelli, L; Jaureguizar, A; Panarello, H O; Cappozzo, H L

2018-05-01

The aim of this study was to analyze the isotopic composition in muscle of striped weakfish Cynoscion guatucupa from Southwest Atlantic Ocean in order to evaluate a possible variation in δ13C and δ15N in response to dietary shifts that occur as animals grow. We also explored for isotopic evidence of differences between sample locations. The results showed an agreement between isotope analysis and previous conventional studies. Differences in the isotope composition between sampling location were not observed. A positive relation exists between isotope values and total body length of the animals. The Cluster analysis defined three groups of size classes, validated by the MDS. Differences in the relative consumption of prey species in each size class were also observed performing isotope mixing models (SIAR). Variation in δ15N among size classes would be associated with the consumption of a different type of prey as animals grow. Small striped weakfish feed on small crustaceans and progressively increase their consumption of fish (anchovy, Engraulis anchoita), increasing by this way their isotope values. On the other hand, differences in δ13C values seemed to be related to age-class specific spatial distribution patterns. Therefore, large and small striped weakfish remain specialized but feeding on different prey at different trophic levels. These results contribute to the study of the diet of striped weakfish, improve the isotopic ecology models and highlight on the importance of accounting for variation in the isotopic composition in response to dietary shifts with the size of one of the most important fishery resources in the region.

Diversity Dynamics in Nymphalidae Butterflies: Effect of Phylogenetic Uncertainty on Diversification Rate Shift Estimates

PubMed Central

Peña, Carlos; Espeland, Marianne

2015-01-01

The species rich butterfly family Nymphalidae has been used to study evolutionary interactions between plants and insects. Theories of insect-hostplant dynamics predict accelerated diversification due to key innovations. In evolutionary biology, analysis of maximum credibility trees in the software MEDUSA (modelling evolutionary diversity using stepwise AIC) is a popular method for estimation of shifts in diversification rates. We investigated whether phylogenetic uncertainty can produce different results by extending the method across a random sample of trees from the posterior distribution of a Bayesian run. Using the MultiMEDUSA approach, we found that phylogenetic uncertainty greatly affects diversification rate estimates. Different trees produced diversification rates ranging from high values to almost zero for the same clade, and both significant rate increase and decrease in some clades. Only four out of 18 significant shifts found on the maximum clade credibility tree were consistent across most of the sampled trees. Among these, we found accelerated diversification for Ithomiini butterflies. We used the binary speciation and extinction model (BiSSE) and found that a hostplant shift to Solanaceae is correlated with increased net diversification rates in Ithomiini, congruent with the diffuse cospeciation hypothesis. Our results show that taking phylogenetic uncertainty into account when estimating net diversification rate shifts is of great importance, as very different results can be obtained when using the maximum clade credibility tree and other trees from the posterior distribution. PMID:25830910

Diversity dynamics in Nymphalidae butterflies: effect of phylogenetic uncertainty on diversification rate shift estimates.

PubMed

Peña, Carlos; Espeland, Marianne

2015-01-01

The species rich butterfly family Nymphalidae has been used to study evolutionary interactions between plants and insects. Theories of insect-hostplant dynamics predict accelerated diversification due to key innovations. In evolutionary biology, analysis of maximum credibility trees in the software MEDUSA (modelling evolutionary diversity using stepwise AIC) is a popular method for estimation of shifts in diversification rates. We investigated whether phylogenetic uncertainty can produce different results by extending the method across a random sample of trees from the posterior distribution of a Bayesian run. Using the MultiMEDUSA approach, we found that phylogenetic uncertainty greatly affects diversification rate estimates. Different trees produced diversification rates ranging from high values to almost zero for the same clade, and both significant rate increase and decrease in some clades. Only four out of 18 significant shifts found on the maximum clade credibility tree were consistent across most of the sampled trees. Among these, we found accelerated diversification for Ithomiini butterflies. We used the binary speciation and extinction model (BiSSE) and found that a hostplant shift to Solanaceae is correlated with increased net diversification rates in Ithomiini, congruent with the diffuse cospeciation hypothesis. Our results show that taking phylogenetic uncertainty into account when estimating net diversification rate shifts is of great importance, as very different results can be obtained when using the maximum clade credibility tree and other trees from the posterior distribution.

Structural, morphological and optical investigations on electron-beam irradiated PbF2-TeO2-B2O3-Eu2O3 glasses

NASA Astrophysics Data System (ADS)

Wagh, Akshatha; Petwal, Vikash; Dwivedi, Jishnu; Upadhyaya, V.; Raviprakash, Y.; Kamath, Sudha D.

2016-09-01

Combined structural, optical and morphological studies were carried out on Eu2O3 doped PbF2-TeO2-B2O3 glass samples, before and after being subjected to electron beam of energy 7.5 MeV. XRD confirmed the amorphous nature of the glasses even after 150 kGy electron beam irradiation. Densities of the irradiated samples showed slightly greater values when compared to their respective values before irradiation, which proved the increase in the compaction of the network. The intensities of the three prominent bands; B-O-B linkages, BO4 units and BO3 units of FT-IR spectra, of the titled glasses, showed slight decrease after electron beam irradiation. The decrement in the values of energy band gap and shift in cut-off wavelength towards red edge, proved the formation of color centers in the glass network after irradiation. The change in Hunter L values, through color measurement was a proof for the Farbe/color/absorption centers created in the glass sites after irradiation.

Tropical Sumatra Squalls drive stable isotope ratios of precipitation in Singapore

NASA Astrophysics Data System (ADS)

He, S.; Niezgoda, K.; Kurita, N.; Wang, X.; Rubin, C. M.; Goodkin, N.

2016-12-01

Sumatra Squalls, organized bands of thunderstorms, are the dominant mesoscale convective systems in the study area during the inter-monsoon and southwest monsoon season. Accompanied by gusty winds and heavy rains, the squalls can be very destructive, affecting Sumatra, the Malay Peninsula and Singapore. To understand how they affect precipitation and its stable isotopes, we continuously analyzed real-time δ-values of precipitation during the squalls in 2015 and also obtained δ-values of daily precipitation. We expect the study will improve our knowledge on cloud dynamics, water cycle during the squalls, and the drive of δ-value of precipitation in the region. We found that δ18O values of precipitation during the squalls mainly exhibit a "V" shape pattern or less commonly a "W" shape pattern. Change in the δ18O value during a single event is approximately 1 to 6‰, with the lowest values mostly observed in the stratiform zone. These observations can be largely explained by the mesoscale subsidence and rain re-evaporation in combination with other processes, such as the entrainment of ambient air. In some events, however, the minimum δ-value occurs in the convection core and coincides with 90% of the total event rainfall, implying a control of rain amount and the dominance of condensation mechanism during these events. Daily precipitation is characterized by periodic negative shifts in its δ18O value. Moreover, the shifts are associated with Sumatra Squalls. Compared to 2014, the frequency of the squalls and corresponding negative shifts in δ-values in 2015 is lower probably due to a weak monsoon. During the ENSO event in 2015, the region was generally drier as a result of reduced moisture convergence with the shift of convection in the western Pacific to the central and eastern Pacific. Therefore, Pacific warm/cold events likely affect the formation of the Sumatra Squalls in the region.

Comparison of qualitative and quantitative evaluation of diffusion-weighted MRI and chemical-shift imaging in the differentiation of benign and malignant vertebral body fractures.

PubMed

Geith, Tobias; Schmidt, Gerwin; Biffar, Andreas; Dietrich, Olaf; Dürr, Hans Roland; Reiser, Maximilian; Baur-Melnyk, Andrea

2012-11-01

The objective of our study was to compare the diagnostic value of qualitative diffusion-weighted imaging (DWI), quantitative DWI, and chemical-shift imaging in a single prospective cohort of patients with acute osteoporotic and malignant vertebral fractures. The study group was composed of patients with 26 osteoporotic vertebral fractures (18 women, eight men; mean age, 69 years; age range, 31 years 6 months to 86 years 2 months) and 20 malignant vertebral fractures (nine women, 11 men; mean age, 63.4 years; age range, 24 years 8 months to 86 years 4 months). T1-weighted, STIR, and T2-weighted sequences were acquired at 1.5 T. A DW reverse fast imaging with steady-state free precession (PSIF) sequence at different delta values was evaluated qualitatively. A DW echo-planar imaging (EPI) sequence and a DW single-shot turbo spin-echo (TSE) sequence at different b values were evaluated qualitatively and quantitatively using the apparent diffusion coefficient. Opposed-phase sequences were used to assess signal intensity qualitatively. The signal loss between in- and opposed-phase images was determined quantitatively. Two-tailed Fisher exact test, Mann-Whitney test, and receiver operating characteristic analysis were performed. Sensitivities, specificities, and accuracies were determined. Qualitative DW-PSIF imaging (delta = 3 ms) showed the best performance for distinguishing between benign and malignant fractures (sensitivity, 100%; specificity, 88.5%; accuracy, 93.5%). Qualitative DW-EPI (b = 50 s/mm(2) [p = 1.00]; b = 250 s/mm(2) [p = 0.50]) and DW single-shot TSE imaging (b = 100 s/mm(2) [p = 1.00]; b = 250 s/mm(2) [p = 0.18]; b = 400 s/mm(2) [p = 0.18]; b = 600 s/mm(2) [p = 0.39]) did not indicate significant differences between benign and malignant fractures. DW-EPI using a b value of 500 s/mm(2) (p = 0.01) indicated significant differences between benign and malignant vertebral fractures. Quantitative DW-EPI (p = 0.09) and qualitative opposed-phase imaging (p = 0.06) did not exhibit significant differences, quantitative DW single-shot TSE imaging (p = 0.002) and quantitative chemical-shift imaging (p = 0.01) showed significant differences between benign and malignant fractures. The DW-PSIF sequence (delta = 3 ms) had the highest accuracy in differentiating benign from malignant vertebral fractures. Quantitative chemical-shift imaging and quantitative DW single-shot TSE imaging had a lower accuracy than DW-PSIF imaging because of a large overlap. Qualitative assessment of opposed-phase, DW-EPI, and DW single-shot TSE sequences and quantitative assessment of the DW-EPI sequence were not suitable for distinguishing between benign and malignant vertebral fractures.

Tracing Pleistocene to Holocene meltwater events and provenance of sediments in Baffin Bay using radiogenic isotope signals

NASA Astrophysics Data System (ADS)

Kirillova, Valeriia; Kasemann, Simone A.; Lucassen, Friedrich

2016-04-01

Large meltwater discharge is the principal carrier of detritus from the continent into the ocean and the dispersion of this detritus by ocean currents is a measure for the spatially focused addition of freshwater in the ocean in the high latitude areas. To trace Greenland ice sheet dynamics and freshwater routing during late Pleistocene to Holocene climate transition, we generate strontium (Sr), neodymium (Nd) and lead (Pb) isotope records on sediment cores in the Baffin Bay: GeoTÜ SL 170, covering the last 18.000 years of climate history and GeoTÜ SL 174, covering 40.000 years. Sr, Nd and Pb isotopes are used as proxies for the provenance of continental detritus and seawater sources. Isotope analyses were performed on two separated fractions from the sedimentary core material: the chemically leached fraction and the remaining detritus. Leachates are supposed to represent Fe-Mn coatings formed on the surface of the sediment grains and to reflect the bottom water signal. The detrital fraction acts as a tracer for the meltwater event and weathering regime of the nearby continental masses. For the detrital fraction of the core SL 170, a pronounced shift can be observed in all three isotope systems at ˜ 12 ka, what coincides with the Younger Dryas cold event. For the detrital fraction the 87Sr/86Sr is around ˜0,72 before the event and reaches up to ˜0,74 after. Nd isotope composition (ɛNd) changed from ˜-26 to ˜-32. The shift suggests a change in the continental sources from West and West-South Greenland to the Baffin Island and Canadian Archipelago. It can be explained by the ice sheet melting processes. The 206Pb/204Pb values for the detrital fraction range from ˜17 before the shift to ˜18 after. On the contrary, the leachates show pronounced radiogenic signatures with values changing from ˜21 to ˜23. The reason for such an unusual high values is most likely in the composition of the leached material, which doesn't seem to show the presence of Fe-Mn coatings as was suggested before. The work on the second core SL 174 is in progress. Up to now the results show similar patterns for isotope ratios as in the case of SL 170.

On the theory of electric double layer with explicit account of a polarizable co-solvent.

PubMed

Budkov, Yu A; Kolesnikov, A L; Kiselev, M G

2016-05-14

We present a continuation of our theoretical research into the influence of co-solvent polarizability on a differential capacitance of the electric double layer. We formulate a modified Poisson-Boltzmann theory, using the formalism of density functional approach on the level of local density approximation taking into account the electrostatic interactions of ions and co-solvent molecules as well as their excluded volume. We derive the modified Poisson-Boltzmann equation, considering the three-component symmetric lattice gas model as a reference system and minimizing the grand thermodynamic potential with respect to the electrostatic potential. We apply present modified Poisson-Boltzmann equation to the electric double layer theory, showing that accounting for the excluded volume of co-solvent molecules and ions slightly changes the main result of our previous simplified theory. Namely, in the case of small co-solvent polarizability with its increase under the enough small surface potentials of electrode, the differential capacitance undergoes the significant growth. Oppositely, when the surface potential exceeds some threshold value (which is slightly smaller than the saturation potential), the increase in the co-solvent polarizability results in a differential capacitance decrease. However, when the co-solvent polarizability exceeds some threshold value, its increase generates a considerable enhancement of the differential capacitance in a wide range of surface potentials. We demonstrate that two qualitatively different behaviors of the differential capacitance are related to the depletion and adsorption of co-solvent molecules at the charged electrode. We show that an additive of the strongly polarizable co-solvent to an electrolyte solution can shift significantly the saturation potential in two qualitatively different manners. Namely, a small additive of strongly polarizable co-solvent results in a shift of saturation potential to higher surface potentials. On the contrary, a sufficiently large additive of co-solvent shifts the saturation potential to lower surface potentials. We obtain that an increase in the co-solvent polarizability makes the electrostatic potential profile longer-ranged. However, increase in the co-solvent concentration in the bulk leads to non-monotonic behavior of the electrostatic potential profile. An increase in the co-solvent concentration in the bulk at its sufficiently small values makes the electrostatic potential profile longer-ranged. Oppositely, when the co-solvent concentration in the bulk exceeds some threshold value, its further increase leads to decrease in electrostatic potential at all distances from the electrode.

ERRATUM: 'MAPPING THE GAS TURBULENCE IN THE COMA CLUSTER: PREDICTIONS FOR ASTRO-H'

NASA Technical Reports Server (NTRS)

Zuhone, J. A.; Markevitch, M.; Zhuravleva, I.

2016-01-01

The published version of this paper contained an error in Figure 5. This figure is intended to show the effect on the structure function of subtracting the bias induced by the statistical and systematic errors on the line shift. The filled circles show the bias-subtracted structure function. The positions of these points in the left panel of the original figure were calculated incorrectly. The figure is reproduced below (with the original caption) with the correct values for the bias-subtracted structure function. No other computations or figures in the original manuscript are affected.

Quasi-soliton scattering in quantum spin chains

NASA Astrophysics Data System (ADS)

Vlijm, R.; Ganahl, M.; Fioretto, D.; Brockmann, M.; Haque, M.; Evertz, H. G.; Caux, J.-S.

2015-12-01

The quantum scattering of magnon bound states in the anisotropic Heisenberg spin chain is shown to display features similar to the scattering of solitons in classical exactly solvable models. Localized colliding Gaussian wave packets of bound magnons are constructed from string solutions of the Bethe equations and subsequently evolved in time, relying on an algebraic Bethe ansatz based framework for the computation of local expectation values in real space-time. The local magnetization profile shows the trajectories of colliding wave packets of bound magnons, which obtain a spatial displacement upon scattering. Analytic predictions on the displacements for various values of anisotropy and string lengths are derived from scattering theory and Bethe ansatz phase shifts, matching time-evolution fits on the displacements. The time-evolved block decimation algorithm allows for the study of scattering displacements from spin-block states, showing similar scattering displacement features.

Quasi-soliton scattering in quantum spin chains

NASA Astrophysics Data System (ADS)

Fioretto, Davide; Vljim, Rogier; Ganahl, Martin; Brockmann, Michael; Haque, Masud; Evertz, Hans-Gerd; Caux, Jean-Sébastien

The quantum scattering of magnon bound states in the anisotropic Heisenberg spin chain is shown to display features similar to the scattering of solitons in classical exactly solvable models. Localized colliding Gaussian wave packets of bound magnons are constructed from string solutions of the Bethe equations and subsequently evolved in time, relying on an algebraic Bethe ansatz based framework for the computation of local expectation values in real space-time. The local magnetization profile shows the trajectories of colliding wave packets of bound magnons, which obtain a spatial displacement upon scattering. Analytic predictions on the displacements for various values of anisotropy and string lengths are derived from scattering theory and Bethe ansatz phase shifts, matching time evolution fits on the displacements. The TEBD algorithm allows for the study of scattering displacements from spin-block states, showing similar displacement scattering features.

Shift report: a ritual play on a residential adolescent psychiatric unit.

PubMed

Yonge, O

2008-01-01

The author conducted an ethnographic study of an adolescent residential psychiatric unit which revealed a category of behaviour--the shift report. A questionnaire was administered to staff to reveal further meanings. Reporting was found to schematize knowledge according to common referents, promote and validate insider roles through language, offer a means of personal reintegration and catharsis, and provide a forum for the symbolic enactment of democratic values which permeated every aspect of culture on the unit. Staff members were categorically in favour of their verbal and private shift report. There was little partitioning of informal and formal aspects of report in the interest of saving time. Instead, socializing and 'catching up' were important aspects of shift report and constituted a large part of team building. The informal nature of report, particularly in the use of language allowed staff to come to terms with frustrations rather than constituting patient stereotyping. As a ritual, the shift report fostered behavioural synchrony, individual empowerment and a democratic 'all-channel network' of communication. It is hoped that this account will encourage more practising nurses and managers to view their shift report as something more than a simple 'handover'; that is, a ritual play of core values, roles and relationships.

Characterization of high affinity (/sup 3/H)triazolam binding in rat brain

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

Earle, M.; Concas, A.; Yamamura, H.I.

1986-03-01

The hypnotic Triazolam (TZ), a triazolo (1,4)-benzodiazepine, displays a short physiological half life and has been used for the treatment of insomnia related to anxiety states. Specific binding properties of this recently tritiated TZ were characterized. The authors major objectives were the direct measurement of the temperature dependence and the GABA effect on (/sup 3/H)TZ binding. Saturation studies showed a shift to lower affinity at 37/sup 0/C (K/sub d/ = 0.25 +/- 0.01 nM at O/sup 0/C; K/sub d/ = 1.46 +/- 0.03 nM at 37/sup 0/C) while the B/sub max/ values remained unchanged (1003 +/- 37 fmoles/mg prot. atmore » 0/sup 0/C and 1001 +/- 43 fmoles/mg prot. at 37/sup 0/C). Inhibition studies showed that (/sup 3/H)TZ binding displayed no GABA shift at 0/sup 0/C(K/sub i/ 0.37 +/- 0.03 nM/- GABA and K/sub i/ = 0.55 +/- 0.13 nM/+GABA) but a nearly two-fold shift was apparent at 37/sup 0/C (K/sub i/ = 2.92 +/- 0.2 nM/-GABA; K/sub i/ = 1.37 +/- 0.11 mM/+GABA). These results were also confirmed by saturation studies in the presence or absence of GABA showing a shift to higher affinity in the presence of GABA only at 37/sup 0/C. In Ro 15-1788/(/sup 3/H)TZ competition experiments the presence of GABA did not affect the inhibitory potency of Ro 15-1788 on (/sup 3/H)TZ binding at both temperatures. In conclusion (/sup 3/H)TZ binding showed an extremely high affinity for benzodiazepine receptors. In contrast to reported literature, the findings suggest that TZ interacts with benzodiazepine receptors similar to other benzodiazepine agonists.« less

Effect of heavy doping on the optical spectra of silicon

NASA Astrophysics Data System (ADS)

Chen, Chen-jia; A, Borghesi; G, Guizzetti; L, Nosenzo; E, Reguzzoni; A, Stella

1985-07-01

In this paper reflectance (R) and thermoreflectance (TR) spectra in heavily doped silicon concerning both interband and intraband transitions are reported and discussed. The heavily doped sample shows a red-shift and lifetime broadening in the two singularities E1(similar 3.4eV) and E2(similar 4.5eV). The values of the scattering time τ extracted from the reflectivity fit are obtained and compared with those obtained from Hall mobility measurements.

Synthesis and photophysical properties of aluminium tris-(4-morpholine-8-hydroxyquinoline)

PubMed Central

Omar, Walaa A.E.

2012-01-01

Aluminium tris(4-morpholinyl-8-hydroxyquinoline) has been synthesized and characterized. The photoluminescence measurements showed that the new derivative is blue shifted and has relative photoluminescence quantum yield two times higher compared to the pristine Al tris(8-hydroxyquinoline). Deferential scanning colorimetric studies revealed that the newly synthesized Alq3 derivative in this work is amorphous material with the highest transition glass temperature value among the reported amorphous Alq3 derivatives. PMID:25685461

Nitrogen Incorporation Effects On Site-Controlled Quantum Dots

NASA Astrophysics Data System (ADS)

Juska, G.; Dimastrodonato, V.; Mereni, L. O.; Pelucchi, E.

2011-12-01

We report here on the optical properties of site-controlled diluted nitride In0.25Ga0.75As1-xNx quantum dots grown by metalorganic vapour phase epitaxy (MOVPE). We show photoluminescence energy shift as a function of nitrogen precursor U-dimethylhydrazine, with a maximum value of 35 meV achieved. Optical features, substantially different from the counterpart nitrogen-free dots, are presented: an antibinding biexciton, a large distribution of lifetimes, significantly reduced fine structure splitting.

Beauty in abstract paintings: perceptual contrast and statistical properties

PubMed Central

Mallon, Birgit; Redies, Christoph; Hayn-Leichsenring, Gregor U.

2014-01-01

In this study, we combined the behavioral and objective approach in the field of empirical aesthetics. First, we studied the perception of beauty by investigating shifts in evaluation on perceived beauty of abstract artworks (Experiment 1). Because the participants showed heterogeneous individual preferences for the paintings, we divided them into seven clusters for the test. The experiment revealed a clear pattern of perceptual contrast. The perceived beauty of abstract paintings increased after exposure to paintings that were rated as less beautiful, and it decreased after exposure to paintings that were rated as more beautiful. Next, we searched for correlations of beauty ratings and perceptual contrast with statistical properties of abstract artworks (Experiment 2). The participants showed significant preferences for particular image properties. These preferences differed between the clusters of participants. Strikingly, next to color measures like hue, saturation, value and lightness, the recently described Pyramid of Histograms of Orientation Gradients (PHOG) self-similarity value seems to be a predictor for aesthetic appreciation of abstract artworks. We speculate that the shift in evaluation in Experiment 1 was, at least in part, based on low-level adaptation to some of the statistical image properties analyzed in Experiment 2. In conclusion, our findings demonstrate that the perception of beauty in abstract artworks is altered after exposure to beautiful or non-beautiful images and correlates with particular image properties, especially color measures and self-similarity. PMID:24711791

Australia is ‘free to choose’ economic growth and falling environmental pressures

NASA Astrophysics Data System (ADS)

Hatfield-Dodds, Steve; Schandl, Heinz; Adams, Philip D.; Baynes, Timothy M.; Brinsmead, Thomas S.; Bryan, Brett A.; Chiew, Francis H. S.; Graham, Paul W.; Grundy, Mike; Harwood, Tom; McCallum, Rebecca; McCrea, Rod; McKellar, Lisa E.; Newth, David; Nolan, Martin; Prosser, Ian; Wonhas, Alex

2015-11-01

Over two centuries of economic growth have put undeniable pressure on the ecological systems that underpin human well-being. While it is agreed that these pressures are increasing, views divide on how they may be alleviated. Some suggest technological advances will automatically keep us from transgressing key environmental thresholds; others that policy reform can reconcile economic and ecological goals; while a third school argues that only a fundamental shift in societal values can keep human demands within the Earth’s ecological limits. Here we use novel integrated analysis of the energy-water-food nexus, rural land use (including biodiversity), material flows and climate change to explore whether mounting ecological pressures in Australia can be reversed, while the population grows and living standards improve. We show that, in the right circumstances, economic and environmental outcomes can be decoupled. Although economic growth is strong across all scenarios, environmental performance varies widely: pressures are projected to more than double, stabilize or fall markedly by 2050. However, we find no evidence that decoupling will occur automatically. Nor do we find that a shift in societal values is required. Rather, extensions of current policies that mobilize technology and incentivize reduced pressure account for the majority of differences in environmental performance. Our results show that Australia can make great progress towards sustainable prosperity, if it chooses to do so.

Australia is 'free to choose' economic growth and falling environmental pressures.

PubMed

Hatfield-Dodds, Steve; Schandl, Heinz; Adams, Philip D; Baynes, Timothy M; Brinsmead, Thomas S; Bryan, Brett A; Chiew, Francis H S; Graham, Paul W; Grundy, Mike; Harwood, Tom; McCallum, Rebecca; McCrea, Rod; McKellar, Lisa E; Newth, David; Nolan, Martin; Prosser, Ian; Wonhas, Alex

2015-11-05

Over two centuries of economic growth have put undeniable pressure on the ecological systems that underpin human well-being. While it is agreed that these pressures are increasing, views divide on how they may be alleviated. Some suggest technological advances will automatically keep us from transgressing key environmental thresholds; others that policy reform can reconcile economic and ecological goals; while a third school argues that only a fundamental shift in societal values can keep human demands within the Earth's ecological limits. Here we use novel integrated analysis of the energy-water-food nexus, rural land use (including biodiversity), material flows and climate change to explore whether mounting ecological pressures in Australia can be reversed, while the population grows and living standards improve. We show that, in the right circumstances, economic and environmental outcomes can be decoupled. Although economic growth is strong across all scenarios, environmental performance varies widely: pressures are projected to more than double, stabilize or fall markedly by 2050. However, we find no evidence that decoupling will occur automatically. Nor do we find that a shift in societal values is required. Rather, extensions of current policies that mobilize technology and incentivize reduced pressure account for the majority of differences in environmental performance. Our results show that Australia can make great progress towards sustainable prosperity, if it chooses to do so.

A new method to detect significant basal body temperature changes during a woman's menstrual cycle.

PubMed

Freundl, Günter; Frank-Herrmann, Petra; Brown, Simon; Blackwell, Leonard

2014-10-01

To compare the results of a computer programme based on the Trigg's tracking system (TTS) identification of the basal body temperature (BBT) shift day from daily records of BBT values (TTS transition day), with the BBT shift day identified from the same records using the Sensiplan(®) symptothermal method of natural family planning. A computer programme was written to display the daily BBT readings for 364 menstrual cycles from 51 women aged 24 to 35 years, obtained from the German Natural Family Planning (NFP) database. The TTS transition day so identified from each record was then compared with the BBT shift day estimated from the same record by the Sensiplan(®) method. Total agreement between the methods was obtained for 81% (294/364) of the cycles and 18% (67) cycles differed by ± 1 day. For the 364 pairs of values distributed among 51 women the medians of the differences between the TTS transition day and Sensiplan(®) initial day of the BBT rise (shift day) were not significantly different (χ(2) = 65.28, df = 50, p = 0.07205). The advantages of the tracking signal algorithm are that in many cases it was possible to identify the BBT shift day on that very day - rather than only some days later - and to estimate the probability that a transition had occurred from the different values of the tracking signal.

Stimulated scattering in Ag nanoparticle colloids

NASA Astrophysics Data System (ADS)

Averyushkin, A. S.; Bulychev, N. A.; Efimkov, V. F.; Erokhin, A. I.; Kazaryan, M. A.; Mikhailov, S. I.; Saraeva, I. N.; Zubarev, I. G.

2017-05-01

A number of features of stimulated thermal Rayleigh scattering (STRS) in pure liquids and nanoparticle solutions are investigated in this work. It is shown that scattering efficiency is not reduced in the case of wide spectral bandwidth pump radiation. It is shown experimentally that the frequency shift of the scattered signal relative to the pump frequency greatly exceeds the theoretical value. It is also shown theoretically that the frequency shift value does not depend on the linewidth of the pump.

A Sea Change in Medicine: Current Shifts in the Delivery and Payment of Medical Care.

PubMed

Bruch, Richard

2016-01-01

The Patient Protection and Affordable Care Act and the Triple Aim are driving a shift toward value-based care. Significant financial risk is being transferred from commercial insurers and government payers to hospital systems and independent physician groups. Medicare has developed bundled payment programs, but legislative barriers still impede the implementation of value-based health care. ©2016 by the North Carolina Institute of Medicine and The Duke Endowment. All rights reserved.

Development of T m -shift genotyping method for detection of cat-derived Giardia lamblia.

PubMed

Pan, Weida; Fu, Yeqi; Abdullahi, Auwalu Yusuf; Wang, Mingwei; Shi, Xianli; Yang, Fang; Yu, Xingang; Yan, Xinxin; Zhang, Pan; Hang, Jianxiong; Li, Guoqing

2017-04-01

To develop T m -shift genotyping method for detection of cat-derived Giardia lamblia, two sets of primers with two GC-rich tails of unequal length attached to their 5'-end were designed according to two SNPs (BG434 and BG170) of β-giardin (bg) gene, and specific PCR products were identified by inspection of a melting curve on real-time PCR thermocycler. A series of experiments on the stability, sensitivity, and accuracy of T m -shift method was tested, and clinical samples were also detected. The results showed that two sets of primers based on SNP could distinguish accurately between assemblages A and F. Coefficient of variation of T m values of assemblage A and F was 0.14 and 0.07% in BG434 and 0.10 and 0.11% in BG170, respectively. The lowest detection concentration was 4.52 × 10 -5 and 4.88 × 10 -5  ng/μL samples of assemblage A and F standard plasmids. The T m -shift genotyping results of ten DNA samples from the cat-derived G. lamblia were consistent with their known genotypes. The detection rate of clinical samples by T m -shift was higher than that by microscopy, and their genotyping results were in complete accordance with sequencing results. It is concluded that the T m -shift genotyping method is rapid, specific, and sensitive and may provide a new technological mean for molecular detection and epidemiological investigation of the cat-derived G. lamblia.

First pressure shift measurement of ozone molecular lines at 9.54 μm using a tunable quantum cascade laser

NASA Astrophysics Data System (ADS)

Minissale, Marco; Zanon-Willette, Thomas; Jeseck, Pascal; Boursier, Corinne; Janssen, Christof

2018-06-01

Using a free-running distributed-feedback quantum cascade laser (QCL) emitting at 9.54 μm, the pressure shift parameters of four intense rovibrational transitions in the ν3 fundamental band of ozone induced by oxygen (O2), air and the noble gases helium (He), argon (Ar), and xenon (Xe) are obtained by employing second harmonic detection. The experimental analysis comprises a full uncertainty budget and provides line shift data which are traceable to SI. The high density of transitions in the ν3 spectral region of ozone make this region particularly difficult to study with more commonly used techniques such as Fourier transform spectroscopy. The comparatively high spectral resolution of the QCL in the MHz range, on the contrary, allows to measure molecular shifts at relatively low pressures (from 2 to 70 hPa), thus reducing the impact of spectral congestion due to pressure broadening of molecular lines. The comparison of our results with published data shows that presently recommended values for the pressure shift are too low in this region. This observation is corroborated by semi-classical calculations using the Robert-Bonamy formalism. A slight negative J dependence, already observed in other ozone vibrational bands, is predicted. Systematic use of our technique could be very useful to support this hypothesis and to make up for the lack of shift parameters for ozone ν3 transitions in molecular spectral databases. A subsequent stabilization of the QCL onto an optical frequency comb will open up possibilities to perform metrological measurements of Doppler-free molecular lines.

Carbon and Nitrogen Isotopes from Top Predator Amino Acids Reveal Rapidly Shifting Ocean Biochemistry in the Outer California Current

PubMed Central

Ruiz-Cooley, Rocio I.; Koch, Paul L.; Fiedler, Paul C.; McCarthy, Matthew D.

2014-01-01

Climatic variation alters biochemical and ecological processes, but it is difficult both to quantify the magnitude of such changes, and to differentiate long-term shifts from inter-annual variability. Here, we simultaneously quantify decade-scale isotopic variability at the lowest and highest trophic positions in the offshore California Current System (CCS) by measuring δ15N and δ13C values of amino acids in a top predator, the sperm whale (Physeter macrocephalus). Using a time series of skin tissue samples as a biological archive, isotopic records from individual amino acids (AAs) can reveal the proximate factors driving a temporal decline we observed in bulk isotope values (a decline of ≥1 ‰) by decoupling changes in primary producer isotope values from those linked to the trophic position of this toothed whale. A continuous decline in baseline (i.e., primary producer) δ15N and δ13C values was observed from 1993 to 2005 (a decrease of ∼4‰ for δ15N source-AAs and 3‰ for δ13C essential-AAs), while the trophic position of whales was variable over time and it did not exhibit directional trends. The baseline δ15N and δ13C shifts suggest rapid ongoing changes in the carbon and nitrogen biogeochemical cycling in the offshore CCS, potentially occurring at faster rates than long-term shifts observed elsewhere in the Pacific. While the mechanisms forcing these biogeochemical shifts remain to be determined, our data suggest possible links to natural climate variability, and also corresponding shifts in surface nutrient availability. Our study demonstrates that isotopic analysis of individual amino acids from a top marine mammal predator can be a powerful new approach to reconstructing temporal variation in both biochemical cycling and trophic structure. PMID:25329915

Carbon and nitrogen isotopes from top predator amino acids reveal rapidly shifting ocean biochemistry in the outer California Current.

PubMed

Ruiz-Cooley, Rocio I; Koch, Paul L; Fiedler, Paul C; McCarthy, Matthew D

2014-01-01

Climatic variation alters biochemical and ecological processes, but it is difficult both to quantify the magnitude of such changes, and to differentiate long-term shifts from inter-annual variability. Here, we simultaneously quantify decade-scale isotopic variability at the lowest and highest trophic positions in the offshore California Current System (CCS) by measuring δ15N and δ13C values of amino acids in a top predator, the sperm whale (Physeter macrocephalus). Using a time series of skin tissue samples as a biological archive, isotopic records from individual amino acids (AAs) can reveal the proximate factors driving a temporal decline we observed in bulk isotope values (a decline of ≥1 ‰) by decoupling changes in primary producer isotope values from those linked to the trophic position of this toothed whale. A continuous decline in baseline (i.e., primary producer) δ15N and δ13C values was observed from 1993 to 2005 (a decrease of ∼4‰ for δ15N source-AAs and 3‰ for δ13C essential-AAs), while the trophic position of whales was variable over time and it did not exhibit directional trends. The baseline δ15N and δ13C shifts suggest rapid ongoing changes in the carbon and nitrogen biogeochemical cycling in the offshore CCS, potentially occurring at faster rates than long-term shifts observed elsewhere in the Pacific. While the mechanisms forcing these biogeochemical shifts remain to be determined, our data suggest possible links to natural climate variability, and also corresponding shifts in surface nutrient availability. Our study demonstrates that isotopic analysis of individual amino acids from a top marine mammal predator can be a powerful new approach to reconstructing temporal variation in both biochemical cycling and trophic structure.

Stress Transfer Quantification in Gelatin-Matrix Natural Composites with Tunable Optical Properties.

PubMed

Quero, Franck; Coveney, Abigail; Lewandowska, Anna E; Richardson, Robert M; Díaz-Calderón, Paulo; Lee, Koon-Yang; Eichhorn, Stephen J; Alam, M Ashraf; Enrione, Javier

2015-06-08

This work reports on the preparation and characterization of natural composite materials prepared from bacterial cellulose (BC) incorporated into a gelatin matrix. Composite morphology was studied using scanning electron microscopy and 2D Raman imaging revealing an inhomogeneous dispersion of BC within the gelatin matrix. The composite materials showed controllable degrees of transparency to visible light and opacity to UV light depending on BC weight fraction. By adding a 10 wt % fraction of BC in gelatin, visible (λ = 550 nm) and UV (λ = 350 nm) transmittances were found to decrease by ∼35 and 40%, respectively. Additionally, stress transfer occurring between the gelatin and BC fibrils was quantified using Raman spectroscopy. This is the first report for a gelatin-matrix composite containing cellulose. As a function of strain, two distinct domains, both showing linear relationships, were observed for which an average initial shift rate with respect to strain of -0.63 ± 0.2 cm(-1)%(-1) was observed, followed by an average shift rate of -0.25 ± 0.03 cm(-1)%(-1). The average initial Raman band shift rate value corresponds to an average effective Young's modulus of 39 ± 13 GPa and 73 ± 25 GPa, respectively, for either a 2D and 3D network of BC fibrils embedded in the gelatin matrix. As a function of stress, a linear relationship was observed with a Raman band shift rate of -27 ± 3 cm(-1)GPa(-1). The potential use of these composite materials as a UV blocking food coating is discussed.

Correlation of interface states/border traps and threshold voltage shift on AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors

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

Wu, Tian-Li, E-mail: Tian-Li.Wu@imec.be; Groeseneken, Guido; Department of Electrical Engineering, KU Leuven, Leuven

2015-08-31

In this paper, three electrical techniques (frequency dependent conductance analysis, AC transconductance (AC-g{sub m}), and positive gate bias stress) were used to evaluate three different gate dielectrics (Plasma-Enhanced Atomic Layer Deposition Si{sub 3}N{sub 4}, Rapid Thermal Chemical Vapor Deposition Si{sub 3}N{sub 4}, and Atomic Layer Deposition (ALD) Al{sub 2}O{sub 3}) for AlGaN/GaN Metal-Insulator-Semiconductor High-Electron-Mobility Transistors. From these measurements, the interface state density (D{sub it}), the amount of border traps, and the threshold voltage (V{sub TH}) shift during a positive gate bias stress can be obtained. The results show that the V{sub TH} shift during a positive gate bias stress ismore » highly correlated to not only interface states but also border traps in the dielectric. A physical model is proposed describing that electrons can be trapped by both interface states and border traps. Therefore, in order to minimize the V{sub TH} shift during a positive gate bias stress, the gate dielectric needs to have a lower interface state density and less border traps. However, the results also show that the commonly used frequency dependent conductance analysis technique to extract D{sub it} needs to be cautiously used since the resulting value might be influenced by the border traps and, vice versa, i.e., the g{sub m} dispersion commonly attributed to border traps might be influenced by interface states.« less

Head growth and neurocognitive outcomes.

PubMed

Wright, Charlotte M; Emond, Alan

2015-06-01

There is a lack of evidence on the value of head circumference (HC) as a screening measure. We aimed to describe the incidence of head centile shifting and the relationship between extremes of head size and later neurodevelopmental problems in the Avon Longitudinal Study of Parents and Children. HC was measured routinely at 2, 9, and 18 or 24 months and by researchers at ages 4, 8, 12, and 18 months. IQ according to the Wechsler Intelligence Scale for Children was measured in research clinics at age 8 for all. Neurocognitive disorders (NCDs) were identified from chart review. There were 10 851 children with ≥2 head measurements. At each age, 2% to 3% of children had scores that were < -2 or >2 SDs below or above the mean, but for most children this was only found at 1 age. More than 15% of children showed centile shifts, but less than one-third of these were sustained at subsequent measurements. Only 0.5% showed a sustained shift beyond the normal range. Children with consistently small heads were up to 7 times more likely to have an NCD, but 85% of children with small heads had no NCDs, and 93% of children with NCDs had head SD scores within the normal range. Centile shifts within the normal range occur commonly and seem mainly to reflect measurement error. This finding makes robust assessment of the head trajectory difficult and may result in many children being investigated unnecessarily. Extreme head size is neither specific nor sensitive for detecting NCDs, suggesting that routine measurement of HC is unhelpful. Copyright © 2015 by the American Academy of Pediatrics.

Staggered work shifts: a way to downsize and restructure an emergency department workforce yet maintain current operational performance.

PubMed

Sinreich, David; Jabali, Ola

2007-09-01

Starting from the last decade of the twentieth century, most hospital Emergency Department (ED) budgets did not keep up with the demand for ED services made by growing populations and aging societies. Since labor consumes over 50% of the total monies invested in EDs and other healthcare systems, any downsizing, streamlining and reorganization plan needs to first address staffing issues such as determining the correct size of the workforce and its work shift scheduling. In this context, it is very important to remember that downsizing certainly does not mean a general cut-across-the-board. This study shows that a selective downsizing process in which each resource is treated separately (increasing the work capacity of some resources is also possible), based on its unique contribution to the overall ED operational performance, can approximately maintain current ED operational measures in terms patient length of stay (LOS) despite an overall reduction in staff hours. A linear optimization model (S-model) and a heuristic iterative simulation based algorithm (SWSSA) are used in this study for scheduling the resources' work shifts, one resource at a time. The algorithm was tested using data that was gathered from five general hospital EDs. By leveling the workload of the different resources in the ED, SWSSA was able to achieve LOS values within -19 to 4% of the original values despite a reduction of 8-17.5% in physicians' work hours and a reduction of 13-47% in the nurses' work hours.

Breath carbon stable isotope ratios identify changes in energy balance and substrate utilization in humans.

PubMed

Whigham, L D; Butz, D E; Johnson, L K; Schoeller, D A; Abbott, D H; Porter, W P; Cook, M E

2014-09-01

Rapid detection of shifts in substrate utilization and energy balance would provide a compelling biofeedback tool for individuals attempting weight loss. As a proof of concept, we tested whether the natural abundance of exhaled carbon stable isotope ratios (breath δ(13)C) reflects shifts between negative and positive energy balance. Volunteers (n=5) consumed a 40% energy-restricted diet for 6 days followed by 50% excess on day 7. Breath was sampled immediately before and 1 h and 2 h after breakfast, lunch and dinner. Exhaled breath δ(13)C values were measured by cavity ring-down spectroscopy. Using repeated measures analysis of variance (ANOVA) followed by Dunnett's contrasts, pre-breakfast breath values on days 2-6 were compared with day 1, and postprandial day 7 time points were compared with pre-breakfast day 7. Energy restriction diminished pre-breakfast breath δ(13)C by day 3 (P<0.05). On day 7, increased energy intake was first detected immediately before dinner (-23.8±0.6 vs -21.9±0.7‰, P=0.002 (means±s.d.)), and breath δ(13)C remained elevated at least 2 h post dinner. In conclusion, when shifting between negative and positive energy balance, breath δ(13)C showed anticipated isotopic changes. Although additional research is needed to determine specificity and repeatability, this method may provide a biomarker for marked increases in caloric intake.

Impact on cognitive functions following gamma knife radiosurgery for cerebral arteriovenous malformations.

PubMed

Raghunath, A; Bennett, Niranjana; Arimappamagan, Arivazhagan; Bhat, Dhananjaya I; Srinivas, Dwarakanath; Thennarasu, K; Jamuna, R; Somanna, Sampath

2016-01-01

Radiosurgery is an alternative to surgical resection of arteriovenous malformation (AVM). Very few studies have addressed the concern of radiation injury to the brain and its attendant adverse effects on cognitive function. This prospective study included all patients who underwent gamma knife radiosurgery (GKRS) at our institute for cerebral AVM between 2006 and December 2008 (n = 34). All patients underwent neuropsychological evaluation before the procedure. Neuropsychological evaluation was repeated in eighteen patients 2 years following GKRS. Clinical outcome, AVM obliteration, and factors influencing outcome were analyzed in these eighteen patients. Before GKRS, more than 50% had significant impairment of neuropsychological functions compared to normal population norms. 66.6% achieved the excellent radiosurgical outcome. At 2 years follow-up, patients showed varied improvement in neuropsychological function in various categories. Pretherapeutic median value for percentage perseverative responses was 26.5 and at follow-up, it reduced to 18.2 (P = 0.039). Set shifting improved in 11 patients (61.1%), remained same in 5 patients (27.7%), and deteriorated in two patients (11.1%). Patients with a higher Spetzler-Martin grade AVM demonstrated a significantly more favorable shift in follow-up test values for set shifting function (P = 0.021). Patients with postradiation imaging changes had lesser tendency to improve in neuropsychological performance at follow-up. GKRS has no clinically harmful effect on cognitive and neuropsychological functioning in patients with brain AVM. On the contrary, there is an improvement in majority of patients at 2 years following radiosurgery when nidus is obliterated.

Correlation of MFOLD-predicted DNA secondary structures with separation patterns obtained by capillary electrophoresis single-strand conformation polymorphism (CE-SSCP) analysis.

PubMed

Glavac, Damjan; Potocnik, Uros; Podpecnik, Darja; Zizek, Teofil; Smerkolj, Sava; Ravnik-Glavac, Metka

2002-04-01

We have studied 57 different mutations within three beta-globin gene promoter fragments with sizes 52 bp, 77 bp, and 193 bp by fluorescent capillary electrophoresis CE-SSCP analysis. For each mutation and wild type, energetically most-favorable predicted secondary structures were calculated for sense and antisense strands using the MFOLD DNA-folding algorithm in order to investigate if any correlation exists between predicted DNA structures and actual CE migration time shifts. The overall CE-SSCP detection rate was 100% for all mutations in three studied DNA fragments. For shorter 52 bp and 77 bp DNA fragments we obtained a positive correlation between the migration time shifts and difference in free energy values of predicted secondary structures at all temperatures. For longer 193 bp beta-globin gene fragments with 46 mutations MFOLD predicted different secondary structures for 89% of mutated strands at 25 degrees C and 40 degrees C. However, the magnitude of the mobility shifts did not necessarily correlate with their secondary structures and free energy values except for the sense strand at 40 degrees C where this correlation was statistically significant (r = 0.312, p = 0.033). Results of this study provided more direct insight into the mechanism of CE-SSCP and showed that MFOLD prediction could be helpful in making decisions about the running temperatures and in prediction of CE-SSCP data patterns, especially for shorter (50-100 bp) DNA fragments. Copyright 2002 Wiley-Liss, Inc.

Future forestland area: impacts from population growth and other factors that affect land values.

Treesearch

Ralph J. Alig; Andrew J. Plantinga

2004-01-01

Shifting patterns of land use in the United States are associated with many of today's environmental concerns. Land-use shifts occur because of relative changes in land rents, which are determined in part by financial returns in commodity markets. In recent decades, more than 3 million ac shifted annually in or out of US forest use. Cross amounts of land-use...

The effects of the NMR shift-reagents Dy(PPP)2, Dy(TTHA) and Tm(DOTP) on developed pressure in isolated perfused rat hearts. The role of shift-reagent calcium complexes.

PubMed

Gaszner, B; Simor, T; Hild, G; Elgavish, G A

2001-11-01

The 23Na NMR shift-reagent complexes (Dy(PPP)2, Dy(TTHA), and Tm(DOTP)) bind stoichiometric amounts of Ca2+. Thus, in perfused rat heart systems, a supplementation of Ca2+ is required to maintain the requisite extracellular free calcium concentration ([Ca(o)]f) and to approximate a physiological level of contractile function. The amount of reagent-bound Ca2+ in a heart perfusate that contains a shift-reagent depends on: (1) Ca2+ binding by excess ligand used during the preparation of the shift-reagent; and (2) the Ca2+ binding affinity of the shift-reagent. To address point 1), we introduced a 1H and 31P NMR spectroscopic titration method to quantify directly the concentration of the excess ligand. We also used this method to minimize the amount of excess ligand (L) and thus the amount of Ca*L complex. To address point (2), we determined the stepwise Kd (microm) values of the Ca complexes of the three shift-reagents.: Dy(PPP)2, Kd=0.09, Kd2=7.9; Dy(TTHA), Kd1=10.66, Kd2=10.12; and Tm(DOTP), K(d1)=0.502, Kd2=4.98. The Kd values of the Ca complexes of the phosphonate and triphosphate based shift-reagents, Tm(DOTP) and Dy(PPP)2, respectively, are lower than those of the polyaminocarboxylate-based Dy(TTHA), indicating stronger Ca binding affinities for the former two types of complexes. We have also shown a positive correlation between [Ca(o)]f and left ventricular developed pressure (LVDP) in perfused rat hearts. Dy(TTHA) has shown no effect on LVDP v[Ca(o)]f. The LVDP values in the presence of the phosphonate and triphosphate based shift-reagents, however, were significantly higher than expected from the [Ca(o)]f levels alone. Thus a positive inotropic effect, independent of [Ca(o)]f, is evident in the presence of Tm(DOTP) or Dy(PPP)2. Copyright 2001 Academic Press.

Multi-proxy geochemical evidence for primary aragonite precipitation in a tropical-shelf 'calcite sea' during the Hirnantian glaciation

NASA Astrophysics Data System (ADS)

Kimmig, Sara R.; Holmden, Chris

2017-06-01

A positive excursion in sedimentary δ26Mg values (2-3‰) is recorded in a mud dominated carbonate succession spanning the Hirnantian glaciation event in a tropical-shelf sea in Nevada. The increase is coincident with lithofacies and biofacies indicators of sea-level change, and previously reported changes in sedimentary δ13C and δ44/40Ca values in the same section. The synchronousness of the isotopic changes is inconsistent with differences in the oceanic residence times of Mg (13 Myr), Ca (0.5-1 Myr), and C (0.1 Myr), indicating that the isotopic trends cannot be attributed to perturbations in the oceanic cycling of these elements. Instead, a mixing analysis (δ26Mg vs. Ca/Mg) reveals that the stratigraphic shift in sedimentary δ26Mg values is an artifact of changing dolomite abundance in the carbonate succession, which increases by an average of ∼12 mol% during the glaciation. The mixing analysis also uncovers stratigraphic changes in end-member limestone δ26Mg values that are tentatively attributed to variations in aragonite abundance. The aragonite, which inverted to calcite during diagenesis, accumulated during the glacio-eustatically controlled sea-level lowstand in the study setting. Although this interpretation is vulnerable to diagenetic effects that are difficult to evaluate, it is strengthened by shifts to lower δ44/40Ca values and higher δ13C values in the same section. Experiments show that aragonite can precipitate in seawater with the chemistry of a 'calcite sea' at temperatures above 20-23 °C. Considering the warm climates of the early Paleozoic, temperatures above this range were likely common in low latitudes. This study shows that the isotopes of Mg, Ca, and C have the potential to fingerprint aragonite that has inverted to calcite in the rock record. It is important recognize carbonate successions where this has occurred so as to avoid misinterpreting facies-dependent changes in carbonate polymorph mineralogy as genuine records of secular changes in the elemental and isotopic geochemistry of seawater.

Functional traits help to explain half-century long shifts in pollinator distributions.

PubMed

Aguirre-Gutiérrez, Jesús; Kissling, W Daniel; Carvalheiro, Luísa G; WallisDeVries, Michiel F; Franzén, Markus; Biesmeijer, Jacobus C

2016-04-15

Changes in climate and land use can have important impacts on biodiversity. Species respond to such environmental modifications by adapting to new conditions or by shifting their geographic distributions towards more suitable areas. The latter might be constrained by species' functional traits that influence their ability to move, reproduce or establish. Here, we show that functional traits related to dispersal, reproduction, habitat use and diet have influenced how three pollinator groups (bees, butterflies and hoverflies) responded to changes in climate and land-use in the Netherlands since 1950. Across the three pollinator groups, we found pronounced areal range expansions (>53%) and modelled range shifts towards the north (all taxa: 17-22 km), west (bees: 14 km) and east (butterflies: 11 km). The importance of specific functional traits for explaining distributional changes varied among pollinator groups. Larval diet preferences (i.e. carnivorous vs. herbivorous/detritivorous and nitrogen values of host plants, respectively) were important for hoverflies and butterflies, adult body size for hoverflies, and flight period length for all groups. Moreover, interactions among multiple traits were important to explain species' geographic range shifts, suggesting that taxon-specific multi-trait analyses are needed to predict how global change will affect biodiversity and ecosystem services.

FBG wavelength demodulation based on a radio frequency optical true time delay method.

PubMed

Wang, Jin; Zhu, Wanshan; Ma, Chenyuan; Xu, Tong

2018-06-01

A new fiber Bragg grating (FBG) wavelength shift demodulation method based on optical true time delay microwave phase detection is proposed. We used a microwave photonic link (MPL) to transport a radio frequency (RF) signal over a dispersion compensation fiber (DCF). The wavelength shift of the FBG will cause the time delay change of the optical carrier that propagates in an optical fiber with chromatic dispersion, which will result in the variation of the RF signal phase. A long DCF was adopted to enlarge the RF signal phase variation. An IQ mixer was used to measure the RF phase variation of the RF signal propagating in the MPL, and the wavelength shift of the FBG can be obtained by the measured RF signal phase variation. The experimental results showed that the wavelength shift measurement resolution is 2 pm when the group velocity dispersion of the DCF is 79.5 ps/nm and the frequency of the RF signal is 18 GHz. The demodulation time is as short as 0.1 ms. The measurement resolution can be improved simply by using a higher frequency of the RF signal and a longer DCF or larger chromatic dispersion value of the DCF.

Coupled-cluster based approach for core-level states in condensed phase: Theory and application to different protonated forms of aqueous glycine

DOE PAGES

Sadybekov, Arman; Krylov, Anna I.

2017-07-07

A theoretical approach for calculating core-level states in condensed phase is presented. The approach is based on equation-of-motion coupled-cluster theory (EOMCC) and effective fragment potential (EFP) method. By introducing an approximate treatment of double excitations in the EOM-CCSD (EOM-CC with single and double substitutions) ansatz, we address poor convergence issues that are encountered for the core-level states and significantly reduce computational costs. While the approximations introduce relatively large errors in the absolute values of transition energies, the errors are systematic. Consequently, chemical shifts, changes in ionization energies relative to reference systems, are reproduced reasonably well. By using different protonation formsmore » of solvated glycine as a benchmark system, we show that our protocol is capable of reproducing the experimental chemical shifts with a quantitative accuracy. The results demonstrate that chemical shifts are very sensitive to the solvent interactions and that explicit treatment of solvent, such as EFP, is essential for achieving quantitative accuracy.« less

Stark effect of Ar I lines for electric field strength diagnostics in the cathode sheath of glow discharge

NASA Astrophysics Data System (ADS)

Vasiljević, Milica M.; Spasojević, Djordje; Šišović, Nikola M.; Konjević, Nikola

2017-09-01

We present a study of argon glow discharge which shows that measured wavenumber DC Stark shifts Δ ν of two neutral argon lines, Ar I 518.75 nm and Ar I 522.127 nm, can be used for reliable determination of the electric field strength F distribution in the cathode sheath region of the discharge. In order to experimentally determine the coefficient c in quadratic correlation Δ ν =cF2 , manifested in a low field range (up to 15 kV/cm), the discharge is seeded with a small admixture of hydrogen, and the values of F are measured via Stark polarization spectroscopy of the hydrogen Balmer beta line. Once known, this can be used for the determination of F by a simple and inexpensive spectroscopic Stark shift measurement in discharges with other argon admixtures or pure argon. Reported shift results are in good agreement with data extrapolated from measurements performed at high electric fields (over 100 kV/cm) by Windholz (Phys. Scr., 21 (1980) 67).

From Drug Safety to Drug Security: A Contemporary Shift in the Policing of Health.

PubMed

Hornberger, Julia

2018-01-29

The counterfeiting of medication is increasingly seen as a major threat to health, especially in the light of both the everyday reliance on and a broadening of world-wide access to pharmaceuticals. Exaggerated or real, this threat has inaugurated, this article argues, a shift from a drug safety regime to a drug security regime that governs the flow of pharmaceuticals and brings together markets, police, and health actors in new ways. This entails a shift from soft disciplinary means aimed at incremental and continued inclusion of defaulters, to one of drastically sovereign measures of exclusion and banishment aimed at fake goods and the people associated with them, in the name of health. Through a multi-sited ethnographic study, this article shows how such new drug security efforts play themselves out especially in (South) Africa, highlighting a modus operandi of spectacular performativity and of working through suspicion and association rather than factuality, producing value less so for those in need of health than for a petty security industry itself. © 2018 by the American Anthropological Association.

Minimization of color shift generated in RGBW quad structure.

NASA Astrophysics Data System (ADS)

Kim, Hong Chul; Yun, Jae Kyeong; Baek, Heume-Il; Kim, Ki Duk; Oh, Eui Yeol; Chung, In Jae

2005-03-01

The purpose of RGBW Quad Structure Technology is to realize higher brightness than that of normal panel (RGB stripe structure) by adding white sub-pixel to existing RGB stripe structure. However, there is side effect called 'color shift' resulted from increasing brightness. This side effect degrades general color characteristics due to change of 'Hue', 'Brightness' and 'Saturation' as compared with existing RGB stripe structure. Especially, skin-tone colors show a tendency to get darker in contrast to normal panel. We"ve tried to minimize 'color shift' through use of LUT (Look Up Table) for linear arithmetic processing of input data, data bit expansion to 12-bit for minimizing arithmetic tolerance and brightness weight of white sub-pixel on each R, G, B pixel. The objective of this study is to minimize and keep Δu'v' value (we commonly use to represent a color difference), quantitative basis of color difference between RGB stripe structure and RGBW quad structure, below 0.01 level (existing 0.02 or higher) using Macbeth colorchecker that is general reference of color characteristics.

The role of dopamine in the timing of Pavlovian conditioned keypecking in ring doves.

PubMed

Ohyama, T; Horvitz, J C; Kitsos, E; Balsam, P D

2001-01-01

The effect of dopaminergic drugs on the timing of conditioned keypecking in ring doves was studied in two experiments. Subjects were given pairings of a keylight with food and the temporal distribution of keypecks was obtained during unreinforced probe trials. Experiment 1 demonstrated that injections of pimozide before each session immediately decreased response rates but shifted timing distributions gradually to the right over several days of treatment. Experiment 2 showed similar results using a longer interstimulus interval (ISI). No shifts were observed when the drug was injected after training sessions, or when a delay, identical to each subject's average latency to eat during the drug condition, was inserted between keylight offset and food presentation. Consequently, the shifts in timing were mediated neither by mere accumulation of the drug nor a delay from keylight offset to food presentation resulting from the drug's ability to slow motor processes. The results suggest that pimozide modulates response rate through its effect on motor processes or incentive value, and response timing through a conditioned response (CR) to injection-related cues established via their repeated pairings with the drug.

Optical properties of aluminum-doped zinc oxide films deposited by direct-current pulse magnetron reactive sputtering

NASA Astrophysics Data System (ADS)

Gao, Xiao-Yong; Chen, Chao; Zhang, Sa

2014-03-01

A series of <103>-oriented aluminum-doped zinc oxide (AZO) films were deposited on glass substrates via direct-current pulse magnetron reactive sputtering at different O2-to-Ar gas flow ratios (GFRs). The optical properties of the films were characterized using the fitted optical constants in the general oscillator model (which contains two Psemi-Tri oscillators) through the use of measured ellipsometric parameters. The refractive index dispersion data below the interband absorption edge were analyzed using a single-oscillator model. The fitted optical energy gap obtained using the single-oscillator model clearly shows a blue shift, followed by a red shift, as the GFR increases from 0.9/18 to 2.1/18. This shift can be attributed to the change in the free electron concentration of the film, which is closely related to the film stress. In addition, the fitted β value indicates that the AZO film falls under the ionic class. The photoluminescence spectrum indicates a photoluminescence mechanism of the direct and wide energy gap semiconductor.

Performance of repaired defects and attPSM in EUV multilayer masks

NASA Astrophysics Data System (ADS)

Deng, Yunfei; La Fontaine, Bruno; Neureuther, Andrew R.

2002-12-01

The imaging performance of non-planar topographies in EUV masks for both partially repaired defects and non-planar attenuating phase-shifting masks made with repair treatments are evaluated using rigorous electromagnetic simulation with TEMPEST. Typical topographies produced by treatment techniques in the literature such as removal of top layers and compaction produced by electron-beam heating are considered. Isolated defects on/near the surface repaired by material removal are shown to result in an image intensity within 5% of the clear field value. Deeply buried defects within the multilayer treated by electron-beam heating can be repaired to 3% of the clear field but over repair can result in some degradation. Compaction from a 6.938 nm period to a 6.312 nm period shows a 540° phase-shift and an intensity reduced to about 6% suggesting such a treatment may be used to create attenuated phase-shifting masks for EUV. The quality of the aerial image for such a mask is studied as a function of the lateral transition distance between treated and untreated regions.

Coupled-cluster based approach for core-level states in condensed phase: Theory and application to different protonated forms of aqueous glycine

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

Sadybekov, Arman; Krylov, Anna I.

A theoretical approach for calculating core-level states in condensed phase is presented. The approach is based on equation-of-motion coupled-cluster theory (EOMCC) and effective fragment potential (EFP) method. By introducing an approximate treatment of double excitations in the EOM-CCSD (EOM-CC with single and double substitutions) ansatz, we address poor convergence issues that are encountered for the core-level states and significantly reduce computational costs. While the approximations introduce relatively large errors in the absolute values of transition energies, the errors are systematic. Consequently, chemical shifts, changes in ionization energies relative to reference systems, are reproduced reasonably well. By using different protonation formsmore » of solvated glycine as a benchmark system, we show that our protocol is capable of reproducing the experimental chemical shifts with a quantitative accuracy. The results demonstrate that chemical shifts are very sensitive to the solvent interactions and that explicit treatment of solvent, such as EFP, is essential for achieving quantitative accuracy.« less

Exposure to varying concentration of fungal spores in grain storage godowns and its effect on the respiratory function status among the workers.

PubMed

Chattopadhyay, Bhaskar P; Das, Satadal; Adhikari, Atin; Alam, Jane

2007-06-01

Grain storage depot workers suffer from different respiratory problems after getting the exposure to storage grain dust. Which is a mixture of pesticides, fungi, silica, bacteria, spores, storage mites, animal hairs, pollens etc. The present study was undertaken to evaluate the fungal spore concentration in summer and winter season as well as the pulmonary function status of the workers; studies are limited in our country. In summer and winter seasons, air sampling was done to measure the airborne fungal spore concentration inside the godowns by Rotorod sampler, UK. Aspergilla, Alternaria, Drechslera, Epicoccum, Nigrospora, Periconia were very much common and found higher in winter compared to summer. The respiratory functional status was assessed in two groups of workers of the same storage grain depot (total n=316) in summer (n=136) and in winter (n=180). List of the workers was collected from the authority and randomly selected every alternate worker and divide them for the studies in summer and winter seasons. Slow Vital Capacity (SVC), Forced Vital Capacity (FVC), and Peak Expiratory Flow Rate (PEFR) were recorded and Forced Expiratory Volume in one second (FEV1), FEV1% and different flow rates were calculated. The Immunoglobulin- E (IgE) level in the blood serum was assessed on post shift pulmonary function tests (PFT) decreased workers. The age, height and weight of the same categories of workers of both studies are highly comparable. Mean PFT values in summer found higher than winter. A gradual decrement of values were found as age was increased but not with duration of exposure. Post-shift PFT was carried in 21.8% (69) workers of which 46.4% (32) workers showed the decrement of values. The serum IgE level of the post-shift PFT decreased subjects was found more than 250 IU/ml in 53.1% (17) workers. Restrictive, obstructive and combined types of respiratory impairments were noticed among the workers. Presence of different spores in varying concentration in the working atmosphere may be responsible for the post shift decrement of PFT, allergic symptoms, high IgE level and respiratory impairments among the workers.

Quantum chemical calculations of glycine glutaric acid

NASA Astrophysics Data System (ADS)

Arioǧlu, ćaǧla; Tamer, Ömer; Avci, Davut; Atalay, Yusuf

2017-02-01

Density functional theory (DFT) calculations of glycine glutaric acid were performed by using B3LYP levels with 6-311++G(d,p) basis set. The theoretical structural parameters such as bond lengths and bond angles are in a good agreement with the experimental values of the title compound. HOMO and LUMO energies were calculated, and the obtained energy gap shows that charge transfer occurs in the title compound. Vibrational frequencies were calculated and compare with experimental ones. 3D molecular surfaces of the title compound were simulated using the same level and basis set. Finally, the 13C and 1H NMR chemical shift values were calculated by the application of the gauge independent atomic orbital (GIAO) method.

Integral equation theory study on the phase separation in star polymer nanocomposite melts.

PubMed

Zhao, Lei; Li, Yi-Gui; Zhong, Chongli

2007-10-21

The polymer reference interaction site model theory is used to investigate phase separation in star polymer nanocomposite melts. Two kinds of spinodal curves were obtained: classic fluid phase boundary for relatively low nanoparticle-monomer attraction strength and network phase boundary for relatively high nanoparticle-monomer attraction strength. The network phase boundaries are much more sensitive with nanoparticle-monomer attraction strength than the fluid phase boundaries. The interference among the arm number, arm length, and nanoparticle-monomer attraction strength was systematically investigated. When the arm lengths are short, the network phase boundary shows a marked shift toward less miscibility with increasing arm number. When the arm lengths are long enough, the network phase boundaries show opposite trends. There exists a crossover arm number value for star polymer nanocomposite melts, below which the network phase separation is consistent with that of chain polymer nanocomposite melts. However, the network phase separation shows qualitatively different behaviors when the arm number is larger than this value.

Anticancer Activity of Ferulic Acid-Inorganic Nanohybrids Synthesized via Two Different Hybridization Routes, Reconstruction and Exfoliation-Reassembly

PubMed Central

Choi, Ae-Jin; Oh, Jae-Min

2013-01-01

We have successfully prepared nanohybrids of biofunctional ferulic acid and layered double hydroxide nanomaterials through reconstruction and exfoliation-reassembly routes. From X-ray diffraction and infrared spectroscopy, both nanohybrids were determined to incorporate ferulic acid molecules in anionic form. Micrsocopic results showed that the nanohybrids had average particle size of 150 nm with plate-like morphology. As the two nanohybridization routes involved crystal disorder and random stacking of layers, the nanohybrids showed slight alteration in z-axis crystallinity and particle size. The zeta potential values of pristine and nanohybrids in deionized water were determined to be positive, while those in cell culture media shifted to negative values. According to the in vitro anticancer activity test on human cervical cancer HeLa cells, it was revealed that nanohybrids showed twice anticancer activity compared with ferulic acid itself. Therefore we could conclude that the nanohybrids of ferulic acid and layered double hydroxide had cellular delivery property of intercalated molecules on cancer cell lines. PMID:24453848

Anticancer activity of ferulic acid-inorganic nanohybrids synthesized via two different hybridization routes, reconstruction and exfoliation-reassembly.

PubMed

Kim, Hyoung-Jun; Ryu, Kitae; Kang, Joo-Hee; Choi, Ae-Jin; Kim, Tae-il; Oh, Jae-Min

2013-01-01

We have successfully prepared nanohybrids of biofunctional ferulic acid and layered double hydroxide nanomaterials through reconstruction and exfoliation-reassembly routes. From X-ray diffraction and infrared spectroscopy, both nanohybrids were determined to incorporate ferulic acid molecules in anionic form. Microscopic results showed that the nanohybrids had average particle size of 150 nm with plate-like morphology. As the two nanohybridization routes involved crystal disorder and random stacking of layers, the nanohybrids showed slight alteration in z-axis crystallinity and particle size. The zeta potential values of pristine and nanohybrids in deionized water were determined to be positive, while those in cell culture media shifted to negative values. According to the in vitro anticancer activity test on human cervical cancer HeLa cells, it was revealed that nanohybrids showed twice anticancer activity compared with ferulic acid itself. Therefore we could conclude that the nanohybrids of ferulic acid and layered double hydroxide had cellular delivery property of intercalated molecules on cancer cell lines.

The distribution shifts of Pinus armandii and its response to temperature and precipitation in China

PubMed Central

Zheng, Xiaofeng; Gao, Pengxiang

2017-01-01

Background The changing climate, particularly in regard to temperature and precipitation, is already affecting tree species’ distributions. Pinus armandii, which dominates on the Yungui Plateau and in the Qinba Mountains in China, is of economic, cultural and ecological value. We wish to test the correlations between the distribution shift of P. armandii and changing climate, and figure out how it tracks future climate change. Methods We sampled the surface soil at sites throughout the distribution of P. armandii to compare the relative abundance of pollen to the current percent cover of plant species. This was used to determine possible changes in the distribution P. armandii. Given the hilly terrain, elevation was considered together with temperature and precipitation as variables correlated with distribution shifts of P. armandii. Results We show that P. armandii is undergoing change in its geographic range, including retraction, a shift to more northern areas and from the upper high part of the mountains to a lower-altitude part in hilly areas. Temperature was the strongest correlate of this distribution shift. Elevation and precipitation were also both significantly correlated with distribution change of P. armandii, but to a lesser degree than temperature. Conclusion The geographic range of P. armandii has been gradually decreasing under the influence of climate change. This provides evidence of the effect of climate change on trees at the species level and suggests that at least some species will have a limited ability to track the changing climate. PMID:28929025

Protein Adsorption and Subsequent Fibroblasts Adhesion on Hydroxyapatite Nanocrystals

NASA Astrophysics Data System (ADS)

Tagaya, Motohiro; Ikoma, Toshiyuki; Takemura, Taro; Hanagata, Nobutaka; Yoshioka, Tomohiko; Tanaka, Junzo

2011-10-01

Quartz crystal microbalance with dissipation (QCM-D) technique was employed for protein adsorption and subsequent fibroblast adhesion on hydroxyapatite (HAp) nanocrystals. The pre-adsorption of three proteins (albumin (BSA) or fibronectin (Fn) or collagen (Col)) and subsequent adsorption of fetal bovine serum (FBS), and the adhesion of fibroblasts on the surface were in situ monitored, and evaluated with the frequency shift (Δf) and dissipation energy shift (ΔD), and the viscoelastic change as ΔD-Δf plot. The Col adsorption showed larger Δf and ΔD values compared with BSA or Fn adsorption, and the subsequent FBS adsorption depended on the pre-adsorbed proteins. The ΔD-Δf plot of the cell adhesion also showed the different behaviour on the surfaces, indicating the process affected by cell-protein interactions. The confocal laser scanning microscope images of adherent cells showed the different morphology and pseudopod on the surfaces. The cells adhered on the surfaces modified with Fn and Col had the uniaxially expanded shape with fibrous pseudopods, while those modified with BSA had round shape. The different cell-protein interaction would cause the arrangement of extracellular matrix and cytoskeleton changes at the interfaces.

Role of Mn2+ concentration in the linear and nonlinear optical properties of Ni1-xMnxSe nanoparticles

NASA Astrophysics Data System (ADS)

Anugop, B.; Prasanth, S.; Rithesh Raj, D.; Vineeshkumar, T. V.; Pranitha, S.; Mahadevan Pillai, V. P.; Sudarsanakumar, C.

2016-12-01

Ni1-xMnxSe nanoparticles (x = 0.1, 0.3, 0.5, 0.7, 0.9) were successfully synthesized by chemical co-precipitation method and their structural and optical properties were studied using X-ray diffraction, transmission electron microscopy, UV-Visible absorption and photo luminescence spectroscopy. XRD pattern reveals the hexagonal structure of the particles and the peak positions were shifted to higher 2θ values with increase in Mn2+ concentration. The average particle size determined from XRD varies from 6 to 11 nm. The UV-Visible absorption spectrum shows absorption edge around the blue region and is red-shifted with increasing Mn2+ concentration consequently the optical bandgap energy is decreasing. The PL emission spectrum shows a broad emission around 380 nm, and the intensity of the emission decreases with increase in Mn2+ concentration. The nonlinear optical properties of the samples were analysed using Z-scan technique and the samples show optical limiting behaviour and the 2 PA coefficient increases with increasing Mn2+ concentration. Overall, manganese concentration influences the linear and nonlinear optical properties of Ni1-xMnxSe nanoparticles.

Work ability and health of security guards at a public University: a cross-sectional study.

PubMed

Godinho, Marluce Rodrigues; Ferreira, Aldo Pacheco; Greco, Rosangela Maria; Teixeira, Liliane Reis; Teixeira, Maria Teresa Bustamante

2016-01-01

to evaluate the work ability and health status of security guards at a public University. a cross-sectional, descriptive, and analytical study was carried with 119 security guards. The following instruments were used: Work Ability Index (WAI), Patient Health Questionnaire (PHQ-9), International Physical Activity Questionnaire (IPAQ, short), Alcohol Use Disorders Identification Test (AUDIT), Medical Outcomes Study (MOS), and Demand-Control-Support (DCS). Descriptive statistics were used to describe the study samples and the Spearman's coefficient correlation was performed to assess the WAI. Significance level was set at 5%. samples were composed by men; the mean age was 54.9 years (SD=5.7); 80% had partners, and 75% had basic education. The majority (95%) had only one job, the average length of service was 24.8 years (SD=11), ranging from 3 to 43 years. 88.9% worked ≤40 hours and 75% did not work at night shift or rotating shifts. The average score given to work ability was good (40.7 points), with significant correlation to social support at work (p-value=0.002), health conditions (p-value=0.094), and depression symptoms (p-value=0.054). this study showed that many characteristics might affect the work ability scores. Considering the results, we note that healthy life habits and a reorganization of work environments should be encouraged.

Work ability and health of security guards at a public University: a cross-sectional study 1

PubMed Central

Godinho, Marluce Rodrigues; Ferreira, Aldo Pacheco; Greco, Rosangela Maria; Teixeira, Liliane Reis; Teixeira, Maria Teresa Bustamante

2016-01-01

Abstract Objective: to evaluate the work ability and health status of security guards at a public University. Methods: a cross-sectional, descriptive, and analytical study was carried with 119 security guards. The following instruments were used: Work Ability Index (WAI), Patient Health Questionnaire (PHQ-9), International Physical Activity Questionnaire (IPAQ, short), Alcohol Use Disorders Identification Test (AUDIT), Medical Outcomes Study (MOS), and Demand-Control-Support (DCS). Descriptive statistics were used to describe the study samples and the Spearman's coefficient correlation was performed to assess the WAI. Significance level was set at 5%. Results: samples were composed by men; the mean age was 54.9 years (SD=5.7); 80% had partners, and 75% had basic education. The majority (95%) had only one job, the average length of service was 24.8 years (SD=11), ranging from 3 to 43 years. 88.9% worked ≤40 hours and 75% did not work at night shift or rotating shifts. The average score given to work ability was good (40.7 points), with significant correlation to social support at work (p-value=0.002), health conditions (p-value=0.094), and depression symptoms (p-value=0.054). Conclusion: this study showed that many characteristics might affect the work ability scores. Considering the results, we note that healthy life habits and a reorganization of work environments should be encouraged. PMID:27463107

Trophic diversity, size and biomass spectrum of Bay of Bengal nematodes: A study case on depth and latitudinal patterns

NASA Astrophysics Data System (ADS)

Ansari, Kapuli Gani Mohamed Thameemul; Lyla, Somasundharanair; Khan, Syed Ajmal; Bhadury, Punyasloke

2017-09-01

Depth and latitudinal patterns of nematode functional attributes were investigated from 35 stations of Bay of Bengal (BoB) continental shelf. We aim to address whether depth and latitudinal variations can modify nematode community structure and their functional attributes (trophic diversity, size and biomass spectra). Global trend of depth and latitudinal related variations have also been noticed from BoB shelf in terms of nematode abundance and species richness, albeit heterogeneity patterns were encountered in functional attributes. Index of trophic diversity values revealed higher trophic diversity across the BoB shelf and suggested variety of food resource availability. However, downstream analysis of trophic status showed depth and latitude specific patterns but not reflected in terms of size and biomass spectrum. The peaks at different positions clearly visualized heterogeneity in distribution patterns for both size and biomass spectrum and also there was evidence of availability of diversified food resources. Nematode biomass spectra (NBS) constructed for nematode communities showed shift in peak biomass values towards lower to moderate size classes particularly in shallower depth but did not get reflected in latitudes. However, Chennai and Parangipettai transects demonstrated shift in peak biomass values towards higher biomass classes explaining the representation of higher nematode abundance. Our findings concluded that depth and latitudes are physical variables; they may not directly affect nematode community structure and functional attributes but they might influence the other factors such as food availability, sediment deposition and settlement rate. Our observations suggest that the local factors (seasonal character) of phytodetrital food flux can be very important for shaping the nematode community structure and success of nematode functional heterogeneity patterns across the Bay of Bengal shelf.

Investigation of human body vibration exposures on haul trucks operating at U.S. surface mines/quarries relative to haul truck activity.

PubMed

Mayton, Alan G; Porter, William L; Xu, Xueyan S; Weston, Eric B; Rubenstein, Elaine N

2018-03-01

Workers who operate mine haul trucks are exposed to whole-body vibration (WBV) on a routine basis. Researchers from the National Institute for Occupational Safety and Health (NIOSH) Pittsburgh Mining Research Division (PMRD) investigated WBV and hand-arm vibration (HAV) exposures for mine/quarry haul truck drivers in relation to the haul truck activities of dumping, loading, and traveling with and without a load. The findings show that WBV measures in weighted root-mean-square accelerations (a w ) and vibration dose value (VDV), when compared to the ISO/ANSI and European Directive 2002/44/EC standards, were mostly below the Exposure Action Value (EAV) identified by the health guidance caution zone (HGCZ). Nevertheless, instances were recorded where the Exposure Limit Value (ELV) was exceeded by more than 500 to 600 percent for VDV x and a wx , respectively. Researchers determined that these excessive levels occurred during the traveling empty activity, when the haul truck descended down grade into the pit loading area, sliding at times, on a wet and slippery road surface caused by rain and overwatering. WBV levels (not normalized to an 8-h shift) for the four haul truck activities showed mean a wz levels for five of the seven drivers exceeding the ISO/ANSI EAV by 9-53 percent for the traveling empty activity. Mean a wx and a wz levels were generally higher for traveling empty and traveling loaded and lower for loading/dumping activities. HAV for measures taken on the steering wheel and shifter were all below the HGCZ which indicates that HAV is not an issue for these drivers/operators when handling steering and shifting control devices.

Dissolved organic nitrogen dynamics in the North Sea: A time series analysis (1995-2005)

NASA Astrophysics Data System (ADS)

Van Engeland, T.; Soetaert, K.; Knuijt, A.; Laane, R. W. P. M.; Middelburg, J. J.

2010-09-01

Dissolved organic nitrogen (DON) dynamics in the North Sea was explored by means of long-term time series of nitrogen parameters from the Dutch national monitoring program. Generally, the data quality was good with little missing data points. Different imputation methods were used to verify the robustness of the patterns against these missing data. No long-term trends in DON concentrations were found over the sampling period (1995-2005). Inter-annual variability in the different time series showed both common and station-specific behavior. The stations could be divided into two regions, based on absolute concentrations and the dominant times scales of variability. Average DON concentrations were 11 μmol l -1 in the coastal region and 5 μmol l -1 in the open sea. Organic fractions of total dissolved nitrogen (TDN) averaged 38 and 71% in the coastal zone and open sea, respectively, but increased over time due to decreasing dissolved inorganic nitrogen (DIN) concentrations. In both regions intra-annual variability dominated over inter-annual variability, but DON variation in the open sea was markedly shifted towards shorter time scales relative to coastal stations. In the coastal zone a consistent seasonal DON cycle existed with high values in spring-summer and low values in autumn-winter. In the open sea seasonality was weak. A marked shift in the seasonality was found at the Dogger Bank, with DON accumulation towards summer and low values in winter prior to 1999, and accumulation in spring and decline throughout summer after 1999. This study clearly shows that DON is a dynamic actor in the North Sea and should be monitored systematically to enable us to understand fully the functioning of this ecosystem.

Investigation of human body vibration exposures on haul trucks operating at U.S. surface mines/quarries relative to haul truck activity

PubMed Central

Mayton, Alan G.; Porter, William L.; Xu, Xueyan S.; Weston, Eric B.; Rubenstein, Elaine N.

2018-01-01

Workers who operate mine haul trucks are exposed to whole-body vibration (WBV) on a routine basis. Researchers from the National Institute for Occupational Safety and Health (NIOSH) Pittsburgh Mining Research Division (PMRD) investigated WBV and hand-arm vibration (HAV) exposures for mine/quarry haul truck drivers in relation to the haul truck activities of dumping, loading, and traveling with and without a load. The findings show that WBV measures in weighted root-mean-square accelerations (aw) and vibration dose value (VDV), when compared to the ISO/ANSI and European Directive 2002/44/EC standards, were mostly below the Exposure Action Value (EAV) identified by the health guidance caution zone (HGCZ). Nevertheless, instances were recorded where the Exposure Limit Value (ELV) was exceeded by more than 500 to 600 percent for VDVx and awx, respectively. Researchers determined that these excessive levels occurred during the traveling empty activity, when the haul truck descended down grade into the pit loading area, sliding at times, on a wet and slippery road surface caused by rain and overwatering. WBV levels (not normalized to an 8-h shift) for the four haul truck activities showed mean awz levels for five of the seven drivers exceeding the ISO/ANSI EAV by 9–53 percent for the traveling empty activity. Mean awx and awz levels were generally higher for traveling empty and traveling loaded and lower for loading/dumping activities. HAV for measures taken on the steering wheel and shifter were all below the HGCZ which indicates that HAV is not an issue for these drivers/operators when handling steering and shifting control devices. PMID:29725145

Errors in the Calculation of 27Al Nuclear Magnetic Resonance Chemical Shifts

PubMed Central

Wang, Xianlong; Wang, Chengfei; Zhao, Hui

2012-01-01

Computational chemistry is an important tool for signal assignment of 27Al nuclear magnetic resonance spectra in order to elucidate the species of aluminum(III) in aqueous solutions. The accuracy of the popular theoretical models for computing the 27Al chemical shifts was evaluated by comparing the calculated and experimental chemical shifts in more than one hundred aluminum(III) complexes. In order to differentiate the error due to the chemical shielding tensor calculation from that due to the inadequacy of the molecular geometry prediction, single-crystal X-ray diffraction determined structures were used to build the isolated molecule models for calculating the chemical shifts. The results were compared with those obtained using the calculated geometries at the B3LYP/6-31G(d) level. The isotropic chemical shielding constants computed at different levels have strong linear correlations even though the absolute values differ in tens of ppm. The root-mean-square difference between the experimental chemical shifts and the calculated values is approximately 5 ppm for the calculations based on the X-ray structures, but more than 10 ppm for the calculations based on the computed geometries. The result indicates that the popular theoretical models are adequate in calculating the chemical shifts while an accurate molecular geometry is more critical. PMID:23203134

A comparative study of the effects of cone-plate and parallel-plate geometries on rheological properties under oscillatory shear flow

NASA Astrophysics Data System (ADS)

Song, Hyeong Yong; Salehiyan, Reza; Li, Xiaolei; Lee, Seung Hak; Hyun, Kyu

2017-11-01

In this study, the effects of cone-plate (C/P) and parallel-plate (P/P) geometries were investigated on the rheological properties of various complex fluids, e.g. single-phase (polymer melts and solutions) and multiphase systems (polymer blend and nanocomposite, and suspension). Small amplitude oscillatory shear (SAOS) tests were carried out to compare linear rheological responses while nonlinear responses were compared using large amplitude oscillatory shear (LAOS) tests at different frequencies. Moreover, Fourier-transform (FT)-rheology method was used to analyze the nonlinear responses under LAOS flow. Experimental results were compared with predictions obtained by single-point correction and shear rate correction. For all systems, SAOS data measured by C/P and P/P coincide with each other, but results showed discordance between C/P and P/P measurements in the nonlinear regime. For all systems except xanthan gum solutions, first-harmonic moduli were corrected using a single horizontal shift factor, whereas FT rheology-based nonlinear parameters ( I 3/1, I 5/1, Q 3, and Q 5) were corrected using vertical shift factors that are well predicted by single-point correction. Xanthan gum solutions exhibited anomalous corrections. Their first-harmonic Fourier moduli were superposed using a horizontal shift factor predicted by shear rate correction applicable to highly shear thinning fluids. The distinguished corrections were observed for FT rheology-based nonlinear parameters. I 3/1 and I 5/1 were superposed by horizontal shifts, while the other systems displayed vertical shifts of I 3/1 and I 5/1. Q 3 and Q 5 of xanthan gum solutions were corrected using both horizontal and vertical shift factors. In particular, the obtained vertical shift factors for Q 3 and Q 5 were twice as large as predictions made by single-point correction. Such larger values are rationalized by the definitions of Q 3 and Q 5. These results highlight the significance of horizontal shift corrections in nonlinear oscillatory shear data.

Changing National Forest Values: a content analysis.

Treesearch

David N. Bengston; Zhi Xu

1995-01-01

Empirically analyzes the evolution of national forest values in recent years. A computerized content analysis procedure was developed and used to analyze the forest value systems of forestry professionals, mainstream environmentalists, and the public. National forest values were found to have shifted significantly over the study period.

Reconstruction of the North Atlantic end-member of the thermohaline circulation across the Mid-Pleistocene Transition

NASA Astrophysics Data System (ADS)

Kim, J.; Seguí, M. J.; Yehudai, M.; Goldstein, S. L.; Pena, L. D.; Raymo, M. E.; Ford, H. L.; Haynes, L.; Farmer, J. R.; Hoenisch, B.

2016-12-01

The dominant periodicity of glacial and interglacial cycles shifted from 41 ky to 100 ky at 1.2-0.8 Ma, marking the Mid-Pleistocene Transition (MPT). Pena and Goldstein (Science, 2014) investigated changes in the Earth's global thermohaline circulation (THC), focusing on South Atlantic cores, and concluded that the THC experienced major disruptions between 950-850 ka (MIS 25 to 21), which generated the climatic conditions that intensified cold periods, prolonged their duration, and stabilized 100 ky cycles. However, knowledge of the coeval North Atlantic is key for interpreting data from the Middle and South Atlantic. We report Nd isotope ratios on Fe-Mn oxide encrusted foraminifera and fish debris from DSDP Site 607 (41.001N; 32.957W, 3427m) between 1.2-0.4 Ma, as a representative of the deep North Atlantic. Pre-MPT results (MIS 35-25) show interglacial ɛNd-values of -13.5 to -14.0, similar to today, and glacial-interglacial variability of 1 ɛNd-unit. Post-MPT results after MIS 19 also show interglacial ɛNd-values of -13.5 to -14.0, but greater glacial-interglacial variability of 2 ɛNd-units. Interglacial-to-glacial transitions throughout the core shift to higher ɛNd-values indicative of weakening THC, except for MIS 26, which is uniquely more negative than the neighboring interglacials, with ɛNd reaching -14.5. During the critical MPT interval of MIS 25-21 recognized by Pena and Goldstein (2014), and continuing beyond it through MIS 19, DSDP 607 ɛNd shows higher values of -11.5 to -12.5, like post-MPT glacials. Thus for the North Atlantic, from the point of view of ɛNd in DSDP 607, post-MPT and pre-MPT interglacials are similar, and post-MPT glacials and MPT glacials are similar. Moreover, comparison to the Pena and Goldstein (2014) South Atlantic data indicates that disruptions to North Atlantic overturning may have begun as early as MIS 27, and the recovery to the pre-MPT interglacial conditions may have been delayed beyond MIS 19.

The Hierarchy of Institutional Values in the Communication Discipline.

ERIC Educational Resources Information Center

Monahan, Jennifer L.; Collins-Jarvis, Lori

1993-01-01

Identifies five overarching values central to disciplinary disputes in communication, and how their relative importance changes depending on prevailing social, economic, and intellectual conditions. Explores discipline-level values in the 1980s, and how value structures are likely to shift in the 1990s. Proposes a value hierarchy for the future.…

Change from slowly rotating 8-hour shifts to rapidly rotating 8-hour and 12-hour shifts using participative shift roster design.

PubMed

Smith, P A; Wright, B M; Mackey, R W; Milsop, H W; Yates, S C

1998-01-01

The study examined the impact of change, from slowly rotating continuous 8-hour shifts to more rapidly rotating continuous 8-hour and 12-hour shifts, on the health and quality of life of shift workers. Self-report survey data were collected from 72 shift workers at 3 sewage treatment plants before and several months after roster change. After the change 1 plant first worked a rapidly rotating, 8-hour shift roster and then worked a 12-hour shift roster, and the other 2 plants worked continuous 12-hour shift rosters. After the change the shift workers at each plant reported increased satisfaction with roster design, a decrease in physical and psychological circadian malaise associated with shift work, improved day sleep quality, less tiredness, and improvements in the quality of home, social and work life. A between-plant comparison of the rapidly rotating 8-hour and 12-hour shift rosters showed greater improvements had been obtained with the 12-hour shift roster, and no significant differences in tiredness or sleep quality between the redesigned 8- and 12-hour shift rosters. However, a within-plant matched-pairs comparison at the 1st plant of the rapidly rotating 8-hour shift roster and the 12-hour shift roster showed no significant differences. The results show that the prior level of support for change may best explain the impact of roster redesign on individual well-being. They lend further support to shift worker participation in roster design.

A New Method for Negative Bias Temperature Instability Assessment in P-Channel Metal Oxide Semiconductor Transistors

NASA Astrophysics Data System (ADS)

Djezzar, Boualem; Tahi, Hakim; Benabdelmoumene, Abdelmadjid; Chenouf, Amel; Kribes, Youcef

2012-11-01

In this paper, we present a new method, named on the fly oxide trap (OTFOT), to extract the bias temperature instability (BTI) in MOS transistors. The OTFOT method is based on charge pumping technique (CP) at low and high frequencies. We emphasize on the theoretical-based concept, giving a clear insight on the easy-use of the OTFOT methodology and demonstrating its viability to characterize the negative BTI (NBTI). Using alternatively high and low frequencies, OTFOT method separates the interface-traps (ΔNit) and border-trap (ΔNbt) (switching oxide-trap) densities independently and also their contributions to the threshold voltage shift (ΔVth), without needing additional methods. The experimental results, from two experimental scenarios, showing the extraction of NBTI-induced shifts caused by interface- and oxide-trap increases are also presented. In the first scenario, all stresses are performed on the same transistor. It exhibits an artifact value of exponent n. In the second scenario, each voltage stress is applied only on one transistor. Its results show an average n of 0.16, 0.05, and 0.11 for NBTI-induced ΔNit, ΔNbt, ΔVth, respectively. Therefore, OTFOT method can contribute to further understand the behavior of the NBTI degradation, especially through the threshold voltage shift components such as ΔVit and ΔVot caused by interface-trap and border-trap, respectively.

Gas-Phase Dopant-Induced Conformational Changes Monitored with Transversal Modulation Ion Mobility Spectrometry.

PubMed

Meyer, Nicole Andrea; Root, Katharina; Zenobi, Renato; Vidal-de-Miguel, Guillermo

2016-02-16

The potential of a Transversal Modulation Ion Mobility Spectrometry (TMIMS) instrument for protein analysis applications has been evaluated. The Collision Cross Section (CCS) of cytochrome c measured with the TMIMS is in agreement with values reported in the literature. Additionally, it enables tandem IMS-IMS prefiltration in dry gas and in vapor doped gas. The chemical specificity of the different dopants enables interesting studies on the structure of proteins as CCS changed strongly depending on the specific dopant. Hexane produced an unexpectedly high CCS shift, which can be utilized to evaluate the exposure of hydrophobic parts of the protein. Alcohols produced higher shifts with a dual behavior: an increase in CCS due to vapor uptake at specific absorption sites, followed by a linear shift typical for unspecific and unstable vapor uptake. The molten globule +8 shows a very specific transition. Initially, its CCS follows the trend of the compact folded states, and then it rapidly increases to the levels of the unfolded states. This strong variation suggests that the +8 charge state undergoes a dopant-induced conformational change. Interestingly, more sterically demanding alcohols seem to unfold the protein more effectively also in the gas phase. This study shows the capabilities of the TMIMS device for protein analysis and how tandem IMS-IMS with dopants could provide better understanding of the conformational changes of proteins.

Multi-proxy reconstructions of hydrologic change during the Eocene-Oligocene transition in the North American Interior

NASA Astrophysics Data System (ADS)

Eley, Y.; Hren, M. T.

2016-12-01

The dramatic shift from a 'greenhouse' to an 'icehouse' world that occurred during the Eocene-Oligocene transition (EOT, 34-33.5 Ma) is associated with changes in atmospheric and oceanic circulation patterns, extinction events in both marine and terrestrial ecosystems, and the establishment of a continental-scale ice sheet on Antarctica. Terrestrial records of the EOT, however, show limited consensus regarding the intensity and impact of this transition, complicating our understanding of how terrestrial hydrology responds to climatic change of this magnitude. Stable isotopes of fossil bones and teeth from the White River Group (WRG) in Nebraska have been interpreted to show an 8 °C decrease in mean annual temperatures across the EOT, with an increase in seasonality, however these studies find no evidence for accompanying changes in aridity. Conversely, other studies have inferred increased aridity in the early Oligocene based on changes in the δ18O and δ13C values of mammalian tooth enamel sampled from the same location. Some of this ambiguity is likely to stem from the difficulty in separating the influence of factors such as temperature, water availability and atmospheric circulation patterns on the δ18O composition of ungulate tooth enamel. We present paired leaf wax biomarker and clay hydrogen isotope data from the WRG to produce a new multi-proxy record of hydrological change and accompanying ecosystem shifts through the EOT in the North American interior. Hydrogen isotopes of clay minerals show a negative shift of <15‰ from the late Eocene through early Oligocene, while in contrast leaf wax n-alkanes record a negative shift in excess of 50‰, in tandem with a positive change in average chain length. We infer an increase in aridity from these data, with an associated potential shift in vegetation cover towards more savannah-style plant species as the climate became drier during the transition into the Oligocene. These data provide new constraints on the impact of the EOT in North America, and highlight the potential role of increasing aridity, in addition to declining temperatures, in shaping the hydrology of the region during this interval.

Repeatability of two-dimensional chemical shift imaging multivoxel proton magnetic resonance spectroscopy for measuring human cerebral choline-containing compounds.

PubMed

Puri, Basant K; Egan, Mary; Wallis, Fintan; Jakeman, Philip

2018-03-22

To investigate the repeatability of proton magnetic resonance spectroscopy in the in vivo measurement of human cerebral levels of choline-containing compounds (Cho). Two consecutive scans were carried out in six healthy resting subjects at a magnetic field strength of 1.5 T. On each occasion, neurospectroscopy data were collected from 64 voxels using the same 2D chemical shift imaging (CSI) sequence. The data were analyzed in the same way, using the same software, to obtain the values for each voxel of the ratio of Cho to creatine. The Wilcoxon related-samples signed-rank test, coefficient of variation (CV), repeatability coefficient (RC), and intraclass correlation coefficient (ICC) were used to assess the repeatability. The CV ranged from 2.75% to 33.99%, while the minimum RC was 5.68%. There was excellent reproducibility, as judged by significant ICC values, in 26 voxels. Just three voxels showed significant differences according to the Wilcoxon related-samples signed-rank test. It is therefore concluded that when CSI multivoxel proton neurospectroscopy is used to measure cerebral choline-containing compounds at 1.5 T, the reproducibility is highly acceptable.

Femininity and masculinity across the menstrual cycle: a relation to mate value.

PubMed

Hromatko, Ivana; Tadinac, Meri; Vranić, Andrea

2008-01-01

Numerous studies have shown that menstrual cycle related variations in sex hormones influence various cognitive processes. These shifts are considered as the evidence for a hormone-mediated adaptive design underlying human mating motivation. In a series of related studies we have shown that (i) femininity does not vary across the menstrual cycle, whereas masculinity is the most pronounced during the fertile period, (ii) masculinity, but not femininity, predicts shifts in spatial cognition across the menstrual cycle, and (iii) women with different positions on masculinity and femininity dimensions differ in their self-perceived mate value. These results suggest that (i) there might be a hormone mediated psychological mechanism making a woman more assertive and dominant during a short time-window when the conception is likely, (ii) menstrual cycle related shifts in cognitive abilities and mating motivation might have a common hormonal mechanism, and (iii) women's mate value (and indirectly her reproductive success) depends upon both feminine and masculine traits.

A measurement of the width and shift of the Fe I 3719.94 A line broadened by helium. [for stellar atmosphere studies

NASA Technical Reports Server (NTRS)

Driver, R. D.; Lombardi, G.

1977-01-01

Results are reported for measurements of the widths and shifts of the overlapping helium-broadened profiles of the Fe I absorption lines at 3719.94 and 3722.56 A, which were performed in a ballistic piston compressor using a saturated solution of FeCl3 in ethanol. It is found that at 4000 K, the 3719.94-A line has a gamma/n (FWHM) value of approximately 5.2 billionths rad/sec per cu cm, the blue shift of this line corresponds to a beta/n value of about 0.49 billionth rad/sec per cu cm, and the 3722.56-A line has the same values. These results are compared with previous experimental determinations and with theoretical calculations of neutral-line broadening for the Fe I lines. The significance of these measurements with respect to the solar spectrum and cool DG white dwarfs is discussed.

a Study of Dilute Aluminum and Vanadium NMR in Alpha-Titanium and in Hydrogen Doped Alpha-Titanium

NASA Astrophysics Data System (ADS)

Chou, Lih-Hsin

Nuclear magnetic resonance was used to investigate Ti-1 at.% V, Ti-2 at.% V, Ti-1 at.% Al, Ti-2 at.% Al and in addition samples of these alloys containing 1 and 2 at.% H. Computer simulation of the absorption curves incorporates the effects of nuclear quadrupole and anisotropic shift interactions, dipolar broadening, and inhomogeneous Knight shift distribution. From the simulation work, experimental parameters such as electric field gradient (EFG), axial anisotropic Knight shift K(,ax), and isotropic Knight shift are obtained. In addition to shedding light on certain features of bonding of V and Al in Ti, this information is used to discuss the trapping of hydrogen in these systems. The resonance of a simple metal (Al) and transition metal (V) at low concentration in a transition metal (Ti) matrix are compared. The localized states of an Al impurity appear to differ radically from the host Ti atomic structure; V present as a dilute solute appears to join the Ti lattice smoothly. Very small isotropic and anisotropic Knight shifts were observed for ('27)Al in Ti. This implies an absence of an orbital contribution and a small value for the s conduction electron density at the local Fermi surface in the vicinity of Al in Ti. A sizeable isotropic and anisotropic Knight shift was observed for ('51)V in Ti. This is thought to be the result of a large orbital contribution. The substitutional vanadium retains much of the character of V, but experiences the symmetry of the Ti lattice. Four outer electrons of V may form nearest neighbor bonds similarly to those between Ti atoms in pure titanium. The one extra electron on the V may be more s-like in character. Measurement of the temperature dependence of K(,ax) and EFG values at V solute atoms in a Ti matrix show that both K(,ax) and EFG increase as temperature decreases. The local electric field gradient contribution from non-s-electrons q(,non -s-el) is about 2 to 5 times larger than the q(,ion) values in magnitude. Because the sign of the EFG is not determined, the validity of the so called "universal correlation" could not be tested. For hydrogen charged Ti-2V alloys, a line shape change was observed at both room and liquid nitrogen temperatures. Thermodynamic and kinetic arguments which include the presence of hydride, dissolved hydrogen, and trapped hydrogen (trapping enthalpy 0.05 eV or greater) are offered to explain the data. No change in the solute resonance line was detected for hydrogen charged Ti-1V, or for hydrogen charged Ti-1Al and Ti-2Al.

β Coronae Bolealis: Lithium and Cerium Contribution to the Blend at 6708 Å

NASA Astrophysics Data System (ADS)

Drake, N. A.; Hubrig, S.; Polosukhina, N. S.; de La Reza, R.

2006-06-01

We analyze the Li I 6708 Å spectral region of the chemically peculiar Ap star βCrB using high resolution, high signal-to-noise spectra obtained at different rotation phases. Our study shows that the Ce II line at 6708.099 Å is a main contributor to the spectral feature at 6708 Å. This fact explains the observed red shift of the Li I doublet of about 0.2 Å found by Hack et al. (1997). We derive the values of lithium and cerium abundances for different rotation phases and show that βCrB has ``cosmic'' Li abundance.

Microstructure, hyperfine interaction and magnetic transition of Fe-25%Ni-5%Si-x%Co alloys

NASA Astrophysics Data System (ADS)

Gungunes, H.

2016-12-01

Morphological and magnetic properties in Fe-25%Ni-5%Si-x%Co (x = 0, 10, 15) alloys are investigated. Scanning electron microscopy (SEM), Mössbauer spectroscopy and AC magnetic susceptibility measurements are used to determine the physical properties of alloys. The martensite morphology changed depending on the Co content. The Mössbauer study shows that the volume fraction and hyperfine field of martensite increases while isomer shift values decrease with increasing Co content. On the other hand; AC susceptibility results showed that; Co is an effective element which can be used to control both the magnetic transition and martensitic transformation temperatures.

Temperature dependence of frequency response characteristics in organic field-effect transistors

NASA Astrophysics Data System (ADS)

Lu, Xubing; Minari, Takeo; Liu, Chuan; Kumatani, Akichika; Liu, J.-M.; Tsukagoshi, Kazuhito

2012-04-01

The frequency response characteristics of semiconductor devices play an essential role in the high-speed operation of electronic devices. We investigated the temperature dependence of dynamic characteristics in pentacene-based organic field-effect transistors and metal-insulator-semiconductor capacitors. As the temperature decreased, the capacitance-voltage characteristics showed large frequency dispersion and a negative shift in the flat-band voltage at high frequencies. The cutoff frequency shows Arrhenius-type temperature dependence with different activation energy values for various gate voltages. These phenomena demonstrate the effects of charge trapping on the frequency response characteristics, since decreased mobility prevents a fast charge response for alternating current signals at low temperatures.

Stable Isotope Analyses of Ancient Penguin Tissues Support the Krill Surplus Hypothesis in Antarctica

NASA Astrophysics Data System (ADS)

Emslie, S. D.; Polito, M. J.; Patterson, W. P.

2010-12-01

The krill surplus hypothesis in Antarctica is based on the premise that historic depletion of krill-eating whales and seals in the 18-20th centuries provided a surplus of krill in the southern ocean that benefited penguins. Previous study of δ13C and δ15N stable isotopes in ancient and modern tissues of Adélie Penguin (Pygoscelis adeliae) from dozens of active and abandoned colonies in Antarctica have provided the first test in support of this hypothesis (Emslie and Patterson 2007). Specifically, there is a significant decrease in both δ13C and δ15N isotope values in modern versus ancient Adélie Penguin tissues from an apparent dietary shift from fish to krill associated with the timing of the purported krill surplus. Here, we present new data on similar analyses of Gentoo Penguin (P. papua) tissues from active and abandoned colonies at two locations in the Antarctic Peninsula to determine if this species recorded a similar shift in its diet in association with the krill surplus. Our results demonstrate a significant decrease (1.5-2.0 ‰) in δ13C in modern versus fossil eggshells (two-tailed t-test of modern versus fossil mean values, t = 1.98, p < 0.0001) in accordance with this hypothesis. δ15N values are more variable among modern localities and probably were so in the past as well. Although we found a weak but significant decrease in δ15N (0.3 ‰) in modern versus fossil eggshell values, we do not consider this to be an adequate signal for a dietary shift. Our data also indicate that the decrease in δ13C values in Gentoo Penguins is not as large as that previously observed in Adélie Penguins (a 4-6 ‰ decrease in δ13C values). This weaker signal for the dietary shift in Gentoo Penguins probably results from a greater and more consistent reliance on fish, past and present, in this species compared to the Adélie Penguin. Emslie, S. D. and W. P. Patterson. 2007. Abrupt recent shift in δ13C and δ15N values in Adélie Penguin eggshell in Antarctica. Proceedings of the National Academy of Sciences 104: 11666-11669. A pair of Adélie Penguins with their well-fed chick.

Using chromium stable isotope ratios to quantify Cr(VI) reduction: Lack of sorption effects

USGS Publications Warehouse

Ellis, A.S.; Johnson, T.M.; Bullen, T.D.

2004-01-01

Chromium stable isotope values can be effectively used to monitor reduction of Cr(VI) in natural waters. We investigate effects of sorption during transport of Cr(VI) which may also shift Cr isotopes values, complicating efforts to quantify reduction. This study shows that Cr stable isotope fractionation caused by sorption is negligible. Equilibrium fractionation of Cr stable isotopes between dissolved Cr-(VI) and Cr(VI) adsorbed onto ??-Al2O3 and goethite is less than 0.04???. (53Cr/52Cr) under environmentally relevant pH conditions. Batch experiments at pH 4.0 and pH 6.0 were conducted in series to sequentially magnify small isotope fractionations. A simple transport model suggests that adsorption may cause amplification of a small isotope fractionation along extreme fringes of a plume, leading to shifts in 53Cr/52Cr values. We therefore suggest that isotope values at extreme fringes of Cr plumes be critically evaluated for sorption effects. A kinetic effect was observed in experiments with goethite at pH 4 where apparently lighter isotopes diffuse into goethite clumps at a faster rate before eventually reaching equilibrium. This observed kinetic effect may be important in a natural system that has not attained equilibrium and is in need of further study. Cr isotope fractionation caused by speciation of Cr(VI) between HCrO4- and CrO42- was also examined, and we conclude that it is not measurable. In the absence of isotope fractionation caused by equilibrium speciation and sorption, most of the variation in ??53 Cr values may be attributed to reduction, and reliable estimates of Cr reduction can be made.

Learning alternative movement coordination patterns using reinforcement feedback.

PubMed

Lin, Tzu-Hsiang; Denomme, Amber; Ranganathan, Rajiv

2018-05-01

One of the characteristic features of the human motor system is redundancy-i.e., the ability to achieve a given task outcome using multiple coordination patterns. However, once participants settle on using a specific coordination pattern, the process of learning to use a new alternative coordination pattern to perform the same task is still poorly understood. Here, using two experiments, we examined this process of how participants shift from one coordination pattern to another using different reinforcement schedules. Participants performed a virtual reaching task, where they moved a cursor to different targets positioned on the screen. Our goal was to make participants use a coordination pattern with greater trunk motion, and to this end, we provided reinforcement by making the cursor disappear if the trunk motion during the reach did not cross a specified threshold value. In Experiment 1, we compared two reinforcement schedules in two groups of participants-an abrupt group, where the threshold was introduced immediately at the beginning of practice; and a gradual group, where the threshold was introduced gradually with practice. Results showed that both abrupt and gradual groups were effective in shifting their coordination patterns to involve greater trunk motion, but the abrupt group showed greater retention when the reinforcement was removed. In Experiment 2, we examined the basis of this advantage in the abrupt group using two additional control groups. Results showed that the advantage of the abrupt group was because of a greater number of practice trials with the desired coordination pattern. Overall, these results show that reinforcement can be successfully used to shift coordination patterns, which has potential in the rehabilitation of movement disorders.

Detecting intraannual dietary variability in wild mountain gorillas by stable isotope analysis of feces

PubMed Central

Blumenthal, Scott A.; Chritz, Kendra L.; Rothman, Jessica M.; Cerling, Thure E.

2012-01-01

We use stable isotope ratios in feces of wild mountain gorillas (Gorilla beringei) to test the hypothesis that diet shifts within a single year, as measured by dry mass intake, can be recovered. Isotopic separation of staple foods indicates that intraannual changes in the isotopic composition of feces reflect shifts in diet. Fruits are isotopically distinct compared with other staple foods, and peaks in fecal δ13C values are interpreted as periods of increased fruit feeding. Bayesian mixing model results demonstrate that, although the timing of these diet shifts match observational data, the modeled increase in proportional fruit feeding does not capture the full shift. Variation in the isotopic and nutritional composition of gorilla foods is largely independent, highlighting the difficulty for estimating nutritional intake with stable isotopes. Our results demonstrate the potential value of fecal sampling for quantifying short-term, intraindividual dietary variability in primates and other animals with high temporal resolution even when the diet is composed of C3 plants. PMID:23236160

Air- and N2-Broadening Coefficients and Pressure-Shift Coefficients in the C-12(O2-16) Laser Bands

NASA Technical Reports Server (NTRS)

Devi, V. Malathy; Benner, D. Chris; Smith, Mary Ann H.; Rinsland, Curtis P.

1998-01-01

In this paper we report the pressure broadening and the pressure-induced line shift coefficients for 46 individual rovibrational lines in both the (12)C(16)O2, 00(sup 0)1-(10(sup 0)0-02(sup 0)0)I, and 00(sup 0)1-(10(sup 0)0-02(sup 0)0)II, laser bands (laser band I centered at 960.959/cm and laser band II centered at 1063.735/cm) determined from spectra recorded with the McMath-Pierce Fourier transform spectrometer. The results were obtained from analysis of 10 long-path laboratory absorption spectra recorded at room temperature using a multispectrum nonlinear least-squares technique. Pressure effects caused by both air and nitrogen have been investigated. The air-broadening coefficients determined in this study agree well with the values in the 1996 HITRAN database; ratios and standard deviations of the ratios of the present air-broadening measurements to the 1996 HITRAN values for the two laser bands are: 1.005(15) for laser band I and 1.005(14) for laser band II. Broadening by nitrogen is 3 to 4% larger than that of air. The pressure-induced line shift coefficients are found to be transition dependent and different for the P- and R-branch lines with same J" value. No noticeable differences in the shift coefficients caused by air and nitrogen were found. The results obtained are compared with available values previously reported in the literature.

PRESSURE SHIFT AND GRAVITATIONAL REDSHIFT OF BALMER LINES IN WHITE DWARFS: REDISCUSSION

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

Halenka, Jacek; Olchawa, Wieslaw; Madej, Jerzy

2015-08-01

The Stark-induced shift and asymmetry, the so-called pressure shift (PS) of H{sub α} and H{sub β} Balmer lines in spectra of DA white dwarfs (WDs), have been examined in detail as masking effects in measurements of the gravitational redshift in WDs. The results are compared with our earlier ones from a quarter of a century ago. In these earlier papers, the standard, symmetrical Stark line profiles, as a dominant constituent of the Balmer line profiles but shifted as a whole by the PS effect, were applied to all spectrally active layers of the WD atmosphere. At present, in each ofmore » the WD layers, the Stark line profiles (especially of H{sub β}) are inherently asymmetrical and shifted due to the effects of strong inhomogeneity of the perturbing fields in plasma. To calculate the Stark line profiles in successive layers of the WD atmosphere we used the modified Full Computer Simulation Method, able to take adequately into account the complexity of local elementary quantum processes in plasma. In the case of the H{sub α} line, the present value of Stark-induced shift of the synthetic H{sub α} line profile is about half the previous one and it is negligible in comparison with the gravitational redshift. In the case of the H{sub β} line, the present value of Stark-induced shift of the synthetic H{sub β} line profile is about twice the previous one. The source of this extra shift is the asymmetry of H{sub β} peaks.« less

Effect of different exposure compounds on urinary kinetics of aluminium and fluoride in industrially exposed workers.

PubMed Central

Pierre, F; Baruthio, F; Diebold, F; Biette, P

1995-01-01

OBJECTIVE--To conduct a field study to obtain information on the urinary concentrations of aluminium (Al) and fluoride (F-) depending on the different compounds exposed to in the aluminum industry. METHODS--16 workers from one plant that produced aluminium fluoride (AlF3), and from two plants that produced aluminium electrolytically by two different processes participated in the study for one working week. Pollutants were monitored by eight hour personal sampling every day, and urine samples were collected during the week. Al and F- were analysed in both atmospheric and urine samples by atomic absorption spectrometry and an ion selective electrode. RESULTS--The principal results show different characteristics of kinetic curves of Al and F- excretion in workers with different exposures. Some characteristics of excretory peaks were linked to specific exposures--for instance, after exposure to AlF3 there was one delayed Al peak associated with one delayed F- peak about eight hours after the end of the daily shift, and after mixed exposure to HF and AlF3, two F- peaks were noted, one fast peak at the end of the shift and another delayed peak at 10 hours synchronised with an Al peak. In one of the electrolysis plants, the exposure to Al and F- compounds led to the simultaneous excretion of Al and F- peaks, either as a single peak or two individual ones depending on the type of technology used on site (open or enclosed potlines). The average estimated half life of Al was 7.5 hours, and of F- about nine hours. Quantitative relations between excretion and exposure showed an association between the F- atmospheric limit value of 2.5 mg/m3 with a urinary F- concentration of 6.4 mg/g creatinine at the end of the shift, a peak of 7.4 mg/g creatinine, and 7.4 mg excreted a day. For Al, the exposure to 1.36 mg/m3 during the shift corresponded to a urinary concentration at the end of the shift of 200 microgram/g creatinine. Daily excretion of 200 micrograms corresponded to an exposure to 0.28 mg/m3. CONCLUSION--Particular differences in the behaviour of Al and F- in urine depended upon the original molecular form in the pollutant. These results reinforce the principle that, in biological monitoring, the sampling strategy and the choice of limit value should be dependent on kinetic data that take the exposure compound of the element in question into account. PMID:7627317

pH shift protein recovery with organic acids on texture and color of cooked gels.

PubMed

Paker, Ilgin; Beamer, Sarah; Jaczynski, Jacek; Matak, Kristen E

2015-01-01

Isoelectric solubilization and precipitation (ISP) processing uses pH shifts to separate protein from fish frames, which may increase commercial interest for silver carp. Texture and color properties of gels made from silver carp protein recovered at different pH strategies and organic acid types were compared. ISP was applied to headed gutted silver carp using 10 mol L(-1) sodium hydroxide (NaOH) and either glacial acetic acid (AA) or a (1:1) formic and lactic acid combination (F&L). Protein gels were made with recovered protein and standard functional additives. Texture profile analysis and the Kramer shear test showed that protein gels made from protein solubilized at basic pH values were firmer, harder, more cohesive, gummier and chewier (P < 0.05) than proteins solubilized under acidic conditions. Acidic solubilization led to whiter (P < 0.05) gels, and using F&L during ISP yielded whiter gels under all treatments (P < 0.05). Gels made from ISP-recovered silver carp protein using organic acids show potential for use as a functional ingredient in restructured foods. © 2014 Society of Chemical Industry.

A novel method for determination of aflatoxin B1 mediated by FCLA + BSA

NASA Astrophysics Data System (ADS)

Chen, WenLi; Xing, Da

2005-02-01

As a chemiluminescence (CL) probe, 3,7-dihydro-6-{4-{2-(N"-(5-fluoresceinyl) thioureido)ethoxy}phenyl}-2-met -hylimi-dazo{1,2-a}pyrazin-3-one dosium salt (FCLA) can sensitively and specifically react with singlet oxygen (1O2 ) and superoxide(O2""). BSA (Bovine Serum Albumin) can enlarge the CL intensity of FCLA to 860%. This report presents a novel method for determination of Aflatoxin B1 (AfB1) mediated by FCLA+BSA. The concentration of AFB1 showed an obvious positive correlation with the CL intensity mediated by FCLA+BSA. This method could measure accurately ng/ml of AfB1 concentration. At the same time, the fluorescence spectrum of FCLA+BSA and FCLA+BSA+AfB1 were measured respectively, which showed that the fluorescence intensity of FCLA+BSA+AfB1 was higher than FCLA+BSA. Comparing the peak value of FCLA, FCLA+BSA and FCLA+BSA+AfB1 had a 6nm Einstein shift (red shift). The study suggested that CL method mediated by FCLA+BSA might be applicable to the determination of AfB1 concentration.

Structure, luminescence and thermal quenching properties of Eu doped Sr2-xBaxSi5N8 red phosphors

NASA Astrophysics Data System (ADS)

Liu, Y. H.; Chen, L.; Zhou, X. F.; Liu, R. H.; Zhuang, W. D.

2017-02-01

Eu2+ doped Sr2-xBaxSi5N8 phosphors were synthesized at 1610 ℃ for 4 h via the solid-state reaction method. The XRD results confirm that the complete solid solutions are formed. With the increase of x, the emission spectra show an obvious blue-shift from 610 nm to 585 nm under the excitation of 460 nm. The color tone can be tuned from yellow to red. The corresponding mechanism for the blue-shift of peak-wavelength is studied in detail. The results of decomposed Gaussian spectra and fluorescence lifetime show that the local coordination structure surrounding activator ions changes with increasing x value. It is found that the probability of Eu occupying Sr1 and Sr2 site is dependent on Ba/Sr ratio. The variation of thermal quenching properties and the corresponding mechanism is discussed in detail. The results indicate that Eu2+ doped Sr2-xBaxSi5N8 is a promising orange red-emitting phosphor for near UV or blue light-pumped white light-emitting-diodes (wLEDs).

Experimental Investigation of the Resistance Performance and Heave and Pitch Motions of Ice-Going Container Ship Under Pack Ice Conditions

NASA Astrophysics Data System (ADS)

Guo, Chun-yu; Xie, Chang; Zhang, Jin-zhao; Wang, Shuai; Zhao, Da-gang

2018-04-01

In order to analyze the ice-going ship's performance under the pack ice conditions, synthetic ice was introduced into a towing tank. A barrier using floating cylinder in the towing tank was designed to carry out the resistance experiment. The test results indicated that the encountering frequency between the ship model and the pack ice shifts towards a high-velocity point as the concentration of the pack ice increases, and this encountering frequency creates an unstable region of the resistance, and the unstable region shifts to the higher speed with the increasing concentration. The results also showed that for the same speed points, the ratio of the pack ice resistance to the open water resistance increases with the increasing concentration, and for the same concentrations, this ratio decreases as the speed increases. Motion characteristics showed that the mean value of the heave motion increases as the speed increases, and the pitch motion tends to increase with the increasing speed. In addition, the total resistance of the fullscale was predicted.

Crystallographic snapshots of active site metal shift in E. coli fructose 1,6-bisphosphate aldolase.

PubMed

Tran, Huyen-Thi; Lee, Seon-Hwa; Ho, Thien-Hoang; Hong, Seung-Hye; Huynh, Kim-Hung; Ahn, Yeh-Jin; Oh, Deok-Kun; Kang, Lin-Woo

2016-12-01

Fructose 1,6-bisphosphate aldolase (FBA) is important for both glycolysis and gluconeogenesis in life. Class II (zinc dependent) FBA is an attractive target for the development of antibiotics against protozoa, bacteria, and fungi, and is also widely used to produce various high-value stereoisomers in the chemical and pharmaceutical industry. In this study, the crystal structures of class II Escherichia coli FBA (EcFBA) were determined from four different crystals, with resolutions between 1.8 Å and 2.0 Å. Native EcFBA structures showed two separate sites of Zn1 (interior position) and Zn2 (active site surface position) for Zn2＋ ion. Citrate and TRIS bound EcFBA structures showed Zn2＋ position exclusively at Zn2. Crystallographic snapshots of EcFBA structures with and without ligand binding proposed the rationale of metal shift at the active site, which might be a hidden mechanism to keep the trace metal cofactor Zn2＋ within EcFBA without losing it. [BMB Reports 2016; 49(12): 681-686].

Efficient elimination of nonstoichiometric enzyme inhibitors from HTS hit lists.

PubMed

Habig, Michael; Blechschmidt, Anke; Dressler, Sigmar; Hess, Barbara; Patel, Viral; Billich, Andreas; Ostermeier, Christian; Beer, David; Klumpp, Martin

2009-07-01

High-throughput screening often identifies not only specific, stoichiometrically binding inhibitors but also undesired compounds that unspecifically interfere with the targeted activity by nonstoichiometrically binding, unfolding, and/or inactivating proteins. In this study, the effect of such unwanted inhibitors on several different enzyme targets was assessed based on screening results for over a million compounds. In particular, the shift in potency on variation of enzyme concentration was used as a means to identify nonstoichiometric inhibitors among the screening hits. These potency shifts depended on both compound structure and target enzyme. The approach was confirmed by statistical analysis of thousands of dose-response curves, which showed that the potency of competitive and therefore clearly stoichiometric inhibitors was not affected by increasing enzyme concentration. Light-scattering measurements of thermal protein unfolding further verified that compounds that stabilize protein structure by stoichiometric binding show the same potency irrespective of enzyme concentration. In summary, measuring inhibitor IC(50) values at different enzyme concentrations is a simple, cost-effective, and reliable method to identify and eliminate compounds that inhibit a specific target enzyme via nonstoichiometric mechanisms.

Stable isotope records of inland California megafauna - new insights into Pleistocene paleoecology and paleoenvironmental conditions

NASA Astrophysics Data System (ADS)

Trayler, R. B.; Dundas, R. G.; Van De Water, P. K.; Fox-Dobbs, K.

2012-12-01

Paleodietary studies of California megafauna have focused primarily on the coastal late Pleistocene Rancho La Brea tar seeps (RLB) in Los Angeles, while other sites remain understudied. We examined two Pleistocene fossil localities from inland California (San Joaquin Valley) and report δ13C and δ18O values measured from tooth enamel of mammalian megafauna at both sites. The late Pleistocene McKittrick tar seeps in Kern County has a similar fauna to RLB. The middle Irvingtonian (~700,000 year old) Fairmead Landfill site, near Chowchilla, contains a megafaunal assemblage dominated by Equus, Camelops and Mammuthus. We used stable isotope values measured in carnivore and herbivore tooth enamel to investigate paleodietary and paleoecological patterns at both sites. δ13C values of tooth enamel is controlled by diet and can be used to investigate resource usage and partitioning among and between taxa. In large mammals δ18O ratios are controlled by drinking water, and by proxy, climate. Ontogenetic serial tooth δ18O and δ13C reveal seasonal trends in resource usage, from which we can infer patterns of forage availability. We sampled 85 individuals from 16 taxa; Arctodus, Bison, Camelops, Canis, Capromeryx, Cervus, Equus, Hemiauchenia, Homotherium, Mammut, Mammuthus, Miracinonyx, Panthera, Platygonus, Smilodon and Tetrameryx. Faunal δ13C differ significantly (p<0.001) between Fairmead and McKittrick, ranging from -13.5‰ to -8.2‰ and -11.8 to -0.7‰, respectively. No significant differences were detected in δ18O between sites (p=0.7). Fairmead δ13C values are consistent with an environment dominated by C3 vegetation. Platygonus and Camelops had the lowest and highest δ13C, respectively. Camelops exhibited the most variable δ13C among herbivores, though several other taxa are represented by single individuals, thus lacking dietary ranges. Among carnivores, Smilodon had the lowest δ13C values (-13.4‰) and Canis latrans the highest (-10.7‰). Carnivore δ13C values only partially overlap the observed range of herbivore values suggesting that not all herbivores were consumed with the same frequency. In comparison to Fairmead, δ13C values from McKittrick show a significant shift in isotopic values suggesting greater C4 plant availability from middle to late Pleistocene. Camelops showed the greatest shift towards C4 plants values, while Cervus had the most negative δ13C value indicating the presence of woodland C3 resources. Within the carnivore guild, Panthera and Arctodus had specialized diets trending towards forested habitats, while canids exhibit generalist diets. We serially sampled multiple teeth from both sites to investigate seasonality and temporal resource usage among megafauna. Equus from both localities showed little variation in δ13C, while at McKittrick Camelops diet included variable amounts of C4 resources throughout a seasonal cycle. We also report the first ever serial sampled Tetrameryx tooth; δ13C variation throughout the tooth is low suggesting a stable diet. Comparing similarly aged inland McKittrick and coastal RLB faunas reveal significant differences (p<0.001). Bison, Equus (Feranec et al., 2009) and Panthera show statistically similar dietary δ13C while Camelops, Canis dirus, Canis latrans and Mammut show significant differences from previously reported RLB analogs (Coltrain et al., 2004).

The new approach for infrared target tracking based on the particle filter algorithm

NASA Astrophysics Data System (ADS)

Sun, Hang; Han, Hong-xia

2011-08-01

Target tracking on the complex background in the infrared image sequence is hot research field. It provides the important basis in some fields such as video monitoring, precision, and video compression human-computer interaction. As a typical algorithms in the target tracking framework based on filtering and data connection, the particle filter with non-parameter estimation characteristic have ability to deal with nonlinear and non-Gaussian problems so it were widely used. There are various forms of density in the particle filter algorithm to make it valid when target occlusion occurred or recover tracking back from failure in track procedure, but in order to capture the change of the state space, it need a certain amount of particles to ensure samples is enough, and this number will increase in accompany with dimension and increase exponentially, this led to the increased amount of calculation is presented. In this paper particle filter algorithm and the Mean shift will be combined. Aiming at deficiencies of the classic mean shift Tracking algorithm easily trapped into local minima and Unable to get global optimal under the complex background. From these two perspectives that "adaptive multiple information fusion" and "with particle filter framework combining", we expand the classic Mean Shift tracking framework .Based on the previous perspective, we proposed an improved Mean Shift infrared target tracking algorithm based on multiple information fusion. In the analysis of the infrared characteristics of target basis, Algorithm firstly extracted target gray and edge character and Proposed to guide the above two characteristics by the moving of the target information thus we can get new sports guide grayscale characteristics and motion guide border feature. Then proposes a new adaptive fusion mechanism, used these two new information adaptive to integrate into the Mean Shift tracking framework. Finally we designed a kind of automatic target model updating strategy to further improve tracking performance. Experimental results show that this algorithm can compensate shortcoming of the particle filter has too much computation, and can effectively overcome the fault that mean shift is easy to fall into local extreme value instead of global maximum value .Last because of the gray and fusion target motion information, this approach also inhibit interference from the background, ultimately improve the stability and the real-time of the target track.

Surface electromyographic evaluation of jaw muscles in children with unilateral crossbite and lateral shift in the early mixed dentition. Sexual dimorphism

PubMed Central

Lenguas, Leticia; Alarcón, José-Antonio; Venancio, Filipa; Kassem, Marta

2012-01-01

Objectives: To examine the activity of jaw muscles at rest and during maximal voluntary clenching (MVC) in children with unilateral posterior crossbite (UPXB) and functional lateral shift in the early mixed dentition and to evaluate sex differences. Material and Methods: The sample included 30 children (15 males, 15 females) aged 6 to 10 years old, with UPXB and functional mandibular lateral shift (≥1.5 mm) in the early mixed dentition. sEMG activity coming from the muscle areas (anterior temporalis [AT], posterior temporalis [PT], masseter [MA] and suprahyoid [SH]) were obtained from both the crossbite (XB) and noncrossbite (NONXB) sides at mandibular rest position. sEMG acti-vity of the bilateral AT and MA muscles sides was obtained during MVC. Asymmetry and activity indexes were calculated for each muscle area at rest and during MVC; the MA/TA ratio during MVC was also determined. Results: At rest, no differences were found between sexes for any muscle areas or asymmetry and activity indexes. No differences were found between XB and NONXB sides. During MVC, however, significant sex differences were found in AT and MA activity, with higher sEMG values in males than in females, on both XB and NONXB sides. Asymmetry indexes, activity indexes and MA/AT ratios did not show significant differences between the sexes. Activity was symmetric both in males and in females. Conclusions: At rest, no sex differences were found, but during MVC males showed higher activity than did females in both XB and NONXB AT and MA muscle areas. Muscular activity was symmetrical at rest and during MVC in both sexes. Sexual dimorphism should be considered in the diagnosis and treatment of UPXB and lateral shift in the early mixed dentition. Key words:Unilateral crossbite, mandibular shift, jaw muscles, sEMG, early mixed dentition. PMID:22926468

Nitrogen Recycling in the Atmosphere - Crust - Mantle Systems: Evidence From Secular Variation of Crustal N Abundances and δ 15N Values, Archean to Present

NASA Astrophysics Data System (ADS)

Jia, Y.; Kerrich, R.

2001-12-01

The origin and evolution of nitrogen in the Earth's major reservoirs of atmosphere, crust, and mantle is controversial. The initial mantle acquired a δ 15N of -m 25‰ corresponding to enstatite chondrite as found in rare diamonds, and the secondary atmosphere from late accretion of volatile-rich C1 carbonaceous chondrites was +30 to +43‰ . Most diamonds and mid-ocean ridge basalts (MORBs) are -m 5‰ , and the present atmosphere 0‰ , requiring shifts of +20‰ and -m 30 to -m 43‰ in these two reservoirs. The present mass of N in the mantle and atmosphere are estimated at 3.5 x 1019 kg and 3.8 x 1018 kg, respectively. Initial atmospheric δ 15N could have been shifted to lower values by degassing of 15N depleted N from the mantle. However, the mantle would remain more depleted than is observed. The crustal record shows that shifts of both atmosphere and mantle could have occurred by recycling. Sedimentary rocks, and crustal hydrothermal systems that proxy for bulk crust, both show systematic trends over 2.7 Ga from the Archean (δ 15N = 15.0 +/- 1.8‰ ; 16.5 +/- 3.3‰ ); through Paleoproterozoic (δ 15N = 9.7 +/- 1.0‰ ; 9.5 +/- 2.4‰ ); to the Phanerozoic (δ 15N = 3.5 +/- 1.0‰ ; 3.0 +/- 1.2‰ ). Crustal N content has increased in parallel from 84 +/- 67 ppm, through 266 +/- 195 ppm, to 1550 +/- 1135 ppm in the Phanerozoic. These trends are consistent with progressive sequestering of atmospheric N2 into sediments, recycling of 15N enriched continental crust into the mantle, and degassing of 15N depleted from the mantle N into the atmosphere.

Determination of Debye temperatures and Lamb-Mössbauer factors for LnFeO3 orthoferrite perovskites (Ln  =  La, Nd, Sm, Eu, Gd)

NASA Astrophysics Data System (ADS)

Scrimshire, A.; Lobera, A.; Bell, A. M. T.; Jones, A. H.; Sterianou, I.; Forder, S. D.; Bingham, P. A.

2018-03-01

Lanthanide orthoferrites have wide-ranging industrial uses including solar, catalytic and electronic applications. Here a series of lanthanide orthoferrite perovskites, LnFeO3 (Ln  =  La Nd; Sm; Eu; Gd), prepared through a standard stoichiometric wet ball milling route using oxide precursors, has been studied. Characterisation through x-ray diffraction and x-ray fluorescence confirmed the synthesis of phase-pure or near-pure LnFeO3 compounds. 57Fe Mössbauer spectroscopy was performed over a temperature range of 10 K-293 K to observe hyperfine structure and to enable calculation of the recoil-free fraction and Debye temperature (θ D) of each orthoferrite. Debye temperatures (Ln  =  La 474 K Nd 459 K Sm 457 K Eu 452 K Gd 473 K) and recoil-free fractions (Ln  =  La 0.827; Nd 0.817; Sm 0.816; Eu 0.812; Gd 0.826) were approximated through minimising the difference in the temperature dependent experimental centre shift and theoretical isomer shift, by allowing the Debye temperature and isomer shift values to vary. This method of minimising the difference between theoretical and actual values yields Debye temperatures consistent with results from other studies determined through thermal analysis methods. This displays the ability of variable-temperature Mössbauer spectroscopy to approximate Debye temperatures and recoil-free fractions, whilst observing temperature induced transitions over the temperature range observed. X-ray diffraction and Rietveld refinement show an inverse relationship between FeO6 octahedral volume and approximated Debye temperatures. Raman spectroscopy show an increase in the band positions attributed to soft modes of Ag symmetry, Ag(3) and Ag(5) from La to GdFeO3 corresponding to octahedral rotations and tilts in the [0 1 0] and [1 0 1] planes respectively.

Cognitive regulation during decision making shifts behavioral control between ventromedial and dorsolateral prefrontal value systems.

PubMed

Hutcherson, Cendri A; Plassmann, Hilke; Gross, James J; Rangel, Antonio

2012-09-26

Cognitive regulation is often used to influence behavioral outcomes. However, the computational and neurobiological mechanisms by which it affects behavior remain unknown. We studied this issue using an fMRI task in which human participants used cognitive regulation to upregulate and downregulate their cravings for foods at the time of choice. We found that activity in both ventromedial prefrontal cortex (vmPFC) and dorsolateral prefrontal cortex (dlPFC) correlated with value. We also found evidence that two distinct regulatory mechanisms were at work: value modulation, which operates by changing the values assigned to foods in vmPFC and dlPFC at the time of choice, and behavioral control modulation, which operates by changing the relative influence of the vmPFC and dlPFC value signals on the action selection process used to make choices. In particular, during downregulation, activation decreased in the value-sensitive region of dlPFC (indicating value modulation) but not in vmPFC, and the relative contribution of the two value signals to behavior shifted toward the dlPFC (indicating behavioral control modulation). The opposite pattern was observed during upregulation: activation increased in vmPFC but not dlPFC, and the relative contribution to behavior shifted toward the vmPFC. Finally, ventrolateral PFC and posterior parietal cortex were more active during both upregulation and downregulation, and were functionally connected with vmPFC and dlPFC during cognitive regulation, which suggests that they help to implement the changes to the decision-making circuitry generated by cognitive regulation.

Cognitive Regulation during Decision Making Shifts Behavioral Control between Ventromedial and Dorsolateral Prefrontal Value Systems

PubMed Central

Plassmann, Hilke; Gross, James J.; Rangel, Antonio

2012-01-01

Cognitive regulation is often used to influence behavioral outcomes. However, the computational and neurobiological mechanisms by which it affects behavior remain unknown. We studied this issue using an fMRI task in which human participants used cognitive regulation to upregulate and downregulate their cravings for foods at the time of choice. We found that activity in both ventromedial prefrontal cortex (vmPFC) and dorsolateral prefrontal cortex (dlPFC) correlated with value. We also found evidence that two distinct regulatory mechanisms were at work: value modulation, which operates by changing the values assigned to foods in vmPFC and dlPFC at the time of choice, and behavioral control modulation, which operates by changing the relative influence of the vmPFC and dlPFC value signals on the action selection process used to make choices. In particular, during downregulation, activation decreased in the value-sensitive region of dlPFC (indicating value modulation) but not in vmPFC, and the relative contribution of the two value signals to behavior shifted toward the dlPFC (indicating behavioral control modulation). The opposite pattern was observed during upregulation: activation increased in vmPFC but not dlPFC, and the relative contribution to behavior shifted toward the vmPFC. Finally, ventrolateral PFC and posterior parietal cortex were more active during both upregulation and downregulation, and were functionally connected with vmPFC and dlPFC during cognitive regulation, which suggests that they help to implement the changes to the decision-making circuitry generated by cognitive regulation. PMID:23015444

Optimization of a pH-shift control strategy for producing monoclonal antibodies in Chinese hamster ovary cell cultures using a pH-dependent dynamic model.

PubMed

Hogiri, Tomoharu; Tamashima, Hiroshi; Nishizawa, Akitoshi; Okamoto, Masahiro

2018-02-01

To optimize monoclonal antibody (mAb) production in Chinese hamster ovary cell cultures, culture pH should be temporally controlled with high resolution. In this study, we propose a new pH-dependent dynamic model represented by simultaneous differential equations including a minimum of six system component, depending on pH value. All kinetic parameters in the dynamic model were estimated using an evolutionary numerical optimization (real-coded genetic algorithm) method based on experimental time-course data obtained at different pH values ranging from 6.6 to 7.2. We determined an optimal pH-shift schedule theoretically. We validated this optimal pH-shift schedule experimentally and mAb production increased by approximately 40% with this schedule. Throughout this study, it was suggested that the culture pH-shift optimization strategy using a pH-dependent dynamic model is suitable to optimize any pH-shift schedule for CHO cell lines used in mAb production projects. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Reduction of the Nonlinear Phase Shift Induced by Stimulated Brillouin Scattering for Bi-Directional Pumping Configuration System Using Particle Swarm Optimization Algorithm

NASA Astrophysics Data System (ADS)

Al-Asadi, H. A.

2013-02-01

We present a theoretical analysis of an additional nonlinear phase shift of backward Stokes wave based on stimulated Brillouin scattering in the system with a bi-directional pumping scheme. We optimize three parameters of the system: the numerical aperture, the optical loss and the pumping wavelength to minimize an additional nonlinear phase shift of backward Stokes waves due to stimulated Brillouin scattering. The optimization is performed with various Brillouin pump powers and the optical reflectivity values are based on the modern, global evolutionary computation algorithm, particle swarm optimization. It is shown that the additional nonlinear phase shift of backward Stokes wave varies with different optical fiber lengths, and can be minimized to less than 0.07 rad according to the particle swarm optimization algorithm for 5 km. The bi-directional pumping configuration system is shown to be efficient when it is possible to transmit the power output to advanced when frequency detuning is negative and delayed when it is positive, with the optimum values of the three parameters to achieve the reduction of an additional nonlinear phase shift.

Shifting to triple value healthcare: Reflections from England.

PubMed

Jani, Anant; Jungmann, Sven; Gray, Muir

2018-02-01

Increasing need and demand because of growing and aging populations combined with stagnant or decreasing resources being invested into healthcare globally mean that a radical shift is needed to ensure that healthcare systems can meet current and future challenges. Quality-, safety- and efficiency-improvement approaches have been used as means to address many problems in healthcare and while they are essential and necessary, they are not sufficient to meet our current challenges. To build resilient and sustainable healthcare systems, we need a shift to focus on triple value healthcare, which will help healthcare professionals improve outcomes at the process, patient and population levels while also optimising resource utilisation. Here we present a brief history of the Quality and Evidence-based Healthcare model and then describe how value emerged as a predominant theme in England. We then highlight the four solutions that we, as part of the RightCare programme, designed and refined in the English NHS to turn theory into practice: We end with a description of how triple value is being introduced into Germany and steps that can be taken to facilitate its adoption. Copyright © 2018. Published by Elsevier GmbH.

Atmospheric studies of C2 white dwarfs

NASA Astrophysics Data System (ADS)

Swanson, Steven Roger

Model atmosphere and line formation calculations for the delta nu = + 1 Swan bands of the C2 molecule are presented for seven white dwarfs and are compared to high resolution optical spectra. Limits on the C-12 to C-13 ratio are computed for highly pressure broadened lines and are used to analyze the observed spectra for any sign of absorption by the (C-12)(C-13) molecule. The metal abundances in cool white dwarf atmospheres and the usefulness of the determination of the C-12 to C-13 ratio are discussed. The line center shift and the pressure broadening are used to determine a value for the van der Waals interaction constant, C6. This is done using a detailed line modelling program which explicitly includes approximately 2000 rotational transition lines within the vibrational bands, in conjunction with atmospheric models calculated by the LUCIFER atmosphere modelling program. The isotopic shift of the vibrational and rotational lines is also included in the model to compare the detectability of various C-12 to C-13 ratios. The line models fit the observed spectra with varying degrees of accuracy. One star, WD0548-001, shows an unusually small pressure shift and broadening for the high pressures that the atmospheric model predicts. The results show that only in the hottest stars with the least pressure broadened lines in this study can the isotopic effect be seen. With the data available, the best limit on the C-12 to C-13 ratio is a minimum of 40 for WD0856 + 331. The models show that even for very high signal to noise data, the isotopic shift in the Swan bands in very cool white dwarfs would be difficult to separate from the pressure broadening effects. It is shown that the isotopic ratio is high enough to rule out the possibility that the carbon is a relic from previous CNO burning.

Absolute Rovibrational Intensities, Self-Broadening and Self-Shift Coefficients for the X(sup 1) Sigma(+) V=3 (left arrow) V=0 Band (C-12)(O-16)

NASA Technical Reports Server (NTRS)

Chackerian, Charles, Jr.; Freedman, R.; Giver, L. P.; Brown, L. R.

2001-01-01

The rotationless transition moment squared for the x(sup 1) sigma (sup +) v=3 (left arrow) v=0 band of CO is measured to be the absolute value of R (sub 3-0) squared = 1.7127(25)x 10(exp -7) Debye squared. This value is about 8.6 percent smaller than the value assumed for HITRAN 2000. The Herman-Wallis intensity factor of this band is F=1+0.01168(11)m+0.0001065(79)m squared. The determination of self-broadening coefficients is improved with the inclusion of line narrowing; self-shifts are also reported.

Isotope shifts in francium isotopes Fr 206 - 213 and Fr 221

DOE PAGES

Collister, R.; Gwinner, G.; Tandecki, M.; ...

2014-11-07

We present the isotope shifts of the 7s 1/2 to 7p 1/2 transition for francium isotopes ²⁰⁶⁻²¹³Fr with reference to ²²¹Fr collected from two experimental periods. The shifts are measured on a sample of atoms prepared within a magneto-optical trap by a fast sweep of radio-frequency sidebands applied to a carrier laser. King plot analysis, which includes literature values for 7s 1/2 to 7p 3/2 isotope shifts, provides a field shift constant ratio of 1.0520(10) and a difference between the specific mass shift constants of 170(100) GHz amu between the D₁ and D₂ transitions, of sufficient precision to differentiate betweenmore » ab initio calculations.« less

Fossil mice and rats show isotopic evidence of niche partitioning and change in dental ecomorphology related to dietary shift in Late Miocene of Pakistan.

PubMed

Kimura, Yuri; Jacobs, Louis L; Cerling, Thure E; Uno, Kevin T; Ferguson, Kurt M; Flynn, Lawrence J; Patnaik, Rajeev

2013-01-01

Stable carbon isotope analysis in tooth enamel is a well-established approach to infer C3 and C4 dietary composition in fossil mammals. The bulk of past work has been conducted on large herbivorous mammals. One important finding is that their dietary habits of fossil large mammals track the late Miocene ecological shift from C3 forest and woodland to C4 savannah. However, few studies on carbon isotopes of fossil small mammals exist due to limitations imposed by the size of rodent teeth, and the isotopic ecological and dietary behaviors of small mammals to climate change remain unknown. Here we evaluate the impact of ecological change on small mammals by fine-scale comparisons of carbon isotope ratios (δ(13)C) with dental morphology of murine rodents, spanning 13.8 to ∼2.0 Ma, across the C3 to C4 vegetation shift in the Miocene Siwalik sequence of Pakistan. We applied in-situ laser ablation GC-IRMS to lower first molars and measured two grazing indices on upper first molars. Murine rodents yield a distinct, but related, record of past ecological conditions from large herbivorous mammals, reflecting available foods in their much smaller home ranges. In general, larger murine species show more positive δ(13)C values and have higher grazing indices than smaller species inhabiting the same area at any given age. Two clades of murine rodents experienced different rates of morphological change. In the faster-evolving clade, the timing and trend of morphological innovations are closely tied to consumption of C4 diet during the vegetation shift. This study provides quantitative evidence of linkages among diet, niche partitioning, and dental morphology at a more detailed level than previously possible.

The Effect of Doppler Frequency Shift, Frequency Offset of the Local Oscillators, and Phase Noise on the Performance of Coherent OFDM Receivers

NASA Technical Reports Server (NTRS)

Xiong, Fuqin; Andro, Monty

2001-01-01

This paper first shows that the Doppler frequency shift affects the frequencies of the RF carrier, subcarriers, envelope, and symbol timing by the same percentage in an Orthogonal Frequency Division Multiplexing (OFDM) signal or any other modulated signals. Then the SNR degradation of an OFDM system due to Doppler frequency shift, frequency offset of the local oscillators and phase noise is analyzed. Expressions are given and values for 4-, 16-, 64-, and 256-QAM OFDM systems are calculated and plotted. The calculations show that the Doppler shift of the D3 project is about 305 kHz, and the degradation due to it is about 0.01 to 0.04 dB, which is negligible. The degradation due to frequency offset and phase noise of local oscillators will be the main source of degradation. To keep the SNR degradation under 0.1 dB, the relative frequency offset due to local oscillators must be below 0.01 for the 16 QAM-OFDM. This translates to an offset of 1.55 MHz (0.01 x 155 MHz) or a stability of 77.5 ppm (0.01 x 155 MHz/20 GHz) for the DI project. To keep the SNR degradation under 0.1 dB, the relative linewidth (0) due to phase noise of the local oscillators must be below 0.0004 for the 16 QAM-OFDM. This translates to a linewidth of 0.062 MHz (0.0004 x 155 MHz) of the 20 GHz RIF carrier. For a degradation of 1 dB, beta = 0.04, and the linewidth can be relaxed to 6.2 MHz.

Fossil Mice and Rats Show Isotopic Evidence of Niche Partitioning and Change in Dental Ecomorphology Related to Dietary Shift in Late Miocene of Pakistan

PubMed Central

Kimura, Yuri; Jacobs, Louis L.; Cerling, Thure E.; Uno, Kevin T.; Ferguson, Kurt M.; Flynn, Lawrence J.; Patnaik, Rajeev

2013-01-01

Stable carbon isotope analysis in tooth enamel is a well-established approach to infer C3 and C4 dietary composition in fossil mammals. The bulk of past work has been conducted on large herbivorous mammals. One important finding is that their dietary habits of fossil large mammals track the late Miocene ecological shift from C3 forest and woodland to C4 savannah. However, few studies on carbon isotopes of fossil small mammals exist due to limitations imposed by the size of rodent teeth, and the isotopic ecological and dietary behaviors of small mammals to climate change remain unknown. Here we evaluate the impact of ecological change on small mammals by fine-scale comparisons of carbon isotope ratios (δ13C) with dental morphology of murine rodents, spanning 13.8 to ∼2.0 Ma, across the C3 to C4 vegetation shift in the Miocene Siwalik sequence of Pakistan. We applied in-situ laser ablation GC-IRMS to lower first molars and measured two grazing indices on upper first molars. Murine rodents yield a distinct, but related, record of past ecological conditions from large herbivorous mammals, reflecting available foods in their much smaller home ranges. In general, larger murine species show more positive δ13C values and have higher grazing indices than smaller species inhabiting the same area at any given age. Two clades of murine rodents experienced different rates of morphological change. In the faster-evolving clade, the timing and trend of morphological innovations are closely tied to consumption of C4 diet during the vegetation shift. This study provides quantitative evidence of linkages among diet, niche partitioning, and dental morphology at a more detailed level than previously possible. PMID:23936324

Laser frequency stabilization by light shift of optical-magnetic double resonances

NASA Astrophysics Data System (ADS)

Zhan, Yuanzhi; Peng, Xiang; Lin, Zaisheng; Gong, Wei; Guo, Hong

2015-05-01

This work adopts the light shift of optical-magnetic double resonance frequency in metastable-state 4He atoms to lock the laser center frequency to the magic point. At this magic frequency, both the left-circularly and right-circularly optical pumping processes will give the same value of optical-magnetic double resonance. With this method and after locking, experimental results show that the laser frequency fluctuation is dramatically reduced to 2.79 MHz in 3600 seconds, comparing with 34.1 MHz drift in the free running mode. In application, with the locked magic laser frequency, the heading error for laser pumped 4He magnetometer can be eliminated much. The National Science Fund for Distinguished Young Scholars of China (Grant No. 61225003), the National Natural Science Foundation of China (Grant No. 61101081), and the National Hi-Tech Research and Development (863) Program.

Normal mode and experimental analysis of TNT Raman spectrum

NASA Astrophysics Data System (ADS)

Liu, Yuemin; Perkins, Richard; Liu, Yucheng; Tzeng, Nianfeng

2017-04-01

In this study, a Raman spectrum of TNT was characterized through experiments and simulated using 22 hybrid density functional theory (DFT) methods. Among the different hybrid DFT methods, it was found that the most accurate simulation results of the Raman shift frequency were calculated by the O3LYP method. However, the deviations of the calculated Raman frequencies from the experimental value showed no dependency on the abilities of the DFT methods in recovering the correlation energy. The accuracies of the DFT methods in predicting the Raman bands are probably determined by the numerical grid and convergence criteria for optimizations of each DFT method. It was also decided that the prominent Raman shift 1362 cm-1 is mainly caused by symmetric stretching of the 4-nitro groups. Findings of this study can facilitate futuristic development of more effective surface enhanced Raman spectroscopy/scattering (SERS) substrates for explosive characterization and detection.

Acoustic sounding of wind velocity profiles in a stratified moving atmosphere.

PubMed

Ostashev, V E; Georges, T M; Clifford, S F; Goedecke, G H

2001-06-01

The paper deals with analytical and numerical studies of the effects of atmospheric stratification on acoustic remote sensing of wind velocity profiles by sodars. Both bistatic and monostatic schemes are considered. Formulas for the Doppler shift of an acoustic echo signal scattered by atmospheric turbulence advected with the mean wind in a stratified moving atmosphere are derived. Numerical studies of these formulas show that errors in retrieving wind velocity can be of the order of 1 m/s if atmospheric stratification is ignored. Formulas for the height at which wind velocity is retrieved are also derived. Approaches are proposed which allow one to take into account the effects of atmospheric stratification when restoring the wind velocity profile from measured values of the Doppler shift and the time interval of acoustic impulse propagation from a sodar to the scattering volume and back to the ground.

Dissecting the indirect effects caused by vaccines into the basic elements.

PubMed

Scarbrough Lefebvre, Carla D; Terlinden, Augustin; Standaert, Baudouin

2015-01-01

Vaccination directly protects vaccinated individuals, but it also has the potential for indirectly protecting the unvaccinated in a population (herd protection). Unintended negative consequences such as the re-manifestation of infection, mainly expressed as age shifts, result from vaccination programs as well. We discuss the necessary conditions for achieving optimal herd protection (i.e., high quality vaccine-induced immunity, substantial effect on the force of infection, and appropriate vaccine coverage and distribution), as well as the conditions under which age shifts are likely to occur. We show examples to illustrate these effects. Substantial ambiguity in observing and quantifying these indirect vaccine effects makes accurate evaluation troublesome even though the nature of these outcomes may be critical for accurate assessment of the economic value when decision makers are evaluating a novel vaccine for introduction into a particular region or population group. More investigation is needed to identify and develop successful assessment methodologies for precisely analyzing these outcomes.

All-optical simultaneous multichannel quadrature phase shift keying signal regeneration based on phase-sensitive amplification

NASA Astrophysics Data System (ADS)

Wang, Hongxiang; Wang, Qi; Bai, Lin; Ji, Yuefeng

2018-01-01

A scheme is proposed to realize the all-optical phase regeneration of four-channel quadrature phase shift keying (QPSK) signal based on phase-sensitive amplification. By utilizing conjugate pump and common pump in a highly nonlinear optical fiber, degenerate four-wave mixing process is observed, and QPSK signals are regenerated. The number of waves is reduced to decrease the cross talk caused by undesired nonlinear interaction during the coherent superposition process. In addition, to avoid the effect of overlapping frequency, frequency spans between pumps and signals are set to be nonintegral multiples. Optical signal-to-noise ratio improvement is validated by bit error rate measurements. Compared with single-channel regeneration, multichannel regeneration brings 0.4-dB OSNR penalty when the value of BER is 10-3, which shows the cross talk in regeneration process is negligible.

Circuit filling factor (CFF) for multiply tuned probes, revisited

NASA Astrophysics Data System (ADS)

Conradi, Mark S.; Zens, Albert P.

2018-07-01

The concept of circuit filling factor (CFF) is re-examined for multi-tuned, multi-inductor probe circuits. The CFF is the fraction of magnetic stored energy residing in the NMR coil. The CFF theorem states that the CFF sums to unity across all the resonant normal modes. It dictates that improved performance from a large CFF in one mode comes at the expense of CFF (and performance) at the other mode(s). Simple analytical calculations of two-mode circuits are used to demonstrate and confirm the CFF theorem. A triple-resonance circuit is calculated to show the large trade-offs involved there. The theorem can provide guidance for choosing the best circuit and relative inductances in multi-nuclear probes. The CFF is directly accessible from ball frequency-shift measurements. We give experimental measures of the CFF from ball shifts and compare to calculated values of the CFF, with good agreement.

Discovery of novel solid solution Ca3Si3-x O3+x N4-2x : Eu2+ phosphors: structural evolution and photoluminescence tuning.

PubMed

Wang, Baochen; Liu, Yan-Gai; Huang, Zhaohui; Fang, Minghao; Wu, Xiaowen

2017-12-22

Discovery of novel phosphors is one of the main issues for improving the color rendering index (CRI) and correlated color temperature (CCT) of white light-emitting diodes (w-LEDs). This study mainly presents a systematic research on the synthesis, crystal structure variation and photoluminescence tuning of novel (oxy)nitride solid solution Ca 3 Si 3-x O 3+x N 4-2x : Eu 2+ phosphors. XRD refinements show that lattice distortion occurs when x value diverges the optimum one (x = 1). The lattice distortion causes a widening of emission spectrum and an increase of Stokes shift (ΔSS), which leads to a bigger thermal quenching. With decrease of x value, the emission spectrum shows an obvious red-shift from 505.2 to 540.8 nm, which is attributed to the crystal field splitting. The enhanced crystal field splitting also broadens the excitation spectrum, making it possible to serve as the phosphor for near ultraviolet (n-UV) LEDs. A 3-phosphor-conversion w-LED lamp was fabricated with the as-prepared phosphor, which exhibits high CRI (Ra = 85.29) and suitable CCT (4903.35 K). All these results indicate that the Ca 3 Si 3-x O 3+x N 4-2x : Eu 2+ phosphor can serve as the green phosphor for n-UV w-LEDs, with a tunable spectrum by controlling the crystal structure and morphology.

The Co-60 gamma-ray irradiation effects on the Al/HfSiO4/p-Si/Al MOS capacitors

NASA Astrophysics Data System (ADS)

Lok, R.; Kaya, S.; Karacali, H.; Yilmaz, E.

2017-12-01

In this work, the initial interface trap density (Nit) to examine device compability for microelectronics and then the Co-60 gamma irradiation responses of Al/HfSiO4/p-Si/Al (MOS) capacitors were investigated in various dose ranges up to 70 Gy. Pre-irradiation response of the devices was evaluated from high frequency (HF) and low frequency (LF) capacitance method and the Nit was calculated as 9.91 × 1011 cm-2 which shows that the HfSiO4/p-Si interface quality is convenient for microelectronics applications. The irradiation responses of the devices were carried out from flat-band and mid-gap voltage shifts obtained from stretch of capacitance characteristics prior to and after irradiation. The results show that the flat band voltages very slightly shifted to positive voltage values demonstrating the enhancement of negative charge trapping in device structure. The sensitivity of the Al/HfSiO4/p-Si/Al MOS capacitors was found to be 4.41 mV/Gy for 300 nm-thick HfSiO4 gate dielectrics. This value approximately 6.5 times smaller compared to the same thickness conventional SiO2 based MOS devices. Therefore, HfSiO4 exhibits crucial irradiation tolerance in gamma irradiation environment. Consequently, HfSiO4 dielectrics may have significant usage for microelectronic technology as a radiation hard material where radiation field exists such as in space applications.

Evaluation of the acoustoelectric effect in the thickness direction of c-plane ZnO single crystals by Brillouin scattering

NASA Astrophysics Data System (ADS)

Tomita, Shota; Yanagitani, Takahiko; Takayanagi, Shinji; Ichihashi, Hayato; Shibagaki, Yoshiaki; Hayashi, Hiromichi; Matsukawa, Mami

2017-06-01

Longitudinal wave velocity dispersion in ZnO single crystals, owing to the acoustoelectric effect, has been investigated by Brillouin scattering. The resistivity dependence of the longitudinal wave velocity in a c-plane ZnO single crystal was theoretically estimated and experimentally investigated. Velocity dispersion owing to the acoustoelectric effect was observed in the range 0.007-10 Ωm. The observed velocity dispersion shows a similar tendency to the theoretical estimation and gives the piezoelectric stiffened and unstiffened wave velocities. However, the measured dispersion curve shows a characteristic shift from the theoretical curve. One possible reason is the carrier mobility in the sample, which could be lower than the reported value. The measurement data gave the piezoelectric stiffened and unstiffened longitudinal wave velocities, from which the electromechanical coupling coefficient k33 was determined. The value of k33 is in good agreement with reported values. This method is promising for noncontact evaluation of electromechanical coupling. In particular, it could be for evaluation of the unknown piezoelectricity in the thickness direction of semiconductive materials and film resonators.

Experimental observation of the shift and width of the aluminium K absorption edge in laser shock-compressed plasmas

NASA Astrophysics Data System (ADS)

Hall, T. A.; Al-Kuzee, J.; Benuzzi, A.; Koenig, M.; Krishnan, J.; Grandjouan, N.; Batani, D.; Bossi, S.; Nicolella, S.

1998-03-01

Experimental measurements of the shift and width of the aluminium K-absorption edge in laser shock-compressed plasma is presented. The spectrometer used in these experiments allows an accurate wavelength calibration and fiduciary and hence provides precise measurements of both the shift and the width of the absorption edge. Results have been obtained for compressions up to approximately ×2 and temperatures up to about 1.5 eV. The values of shift and width are compared with a new model with which there is very good agreement.

Stable isotope evidence for increasing dietary breadth in the European mid-Upper Paleolithic

PubMed Central

Richards, Michael P.; Pettitt, Paul B.; Stiner, Mary C.; Trinkaus, Erik

2001-01-01

New carbon and nitrogen stable isotope values for human remains dating to the mid-Upper Paleolithic in Europe indicate significant amounts of aquatic (fish, mollusks, and/or birds) foods in some of their diets. Most of this evidence points to exploitation of inland freshwater aquatic resources in particular. By contrast, European Neandertal collagen carbon and nitrogen stable isotope values do not indicate significant use of inland aquatic foods but instead show that they obtained the majority of their protein from terrestrial herbivores. In agreement with recent zooarcheological analyses, the isotope results indicate shifts toward a more broad-spectrum subsistence economy in inland Europe by the mid-Upper Paleolithic period, probably associated with significant population increases. PMID:11371652

Stable isotope evidence for increasing dietary breadth in the European mid-Upper Paleolithic.

PubMed

Richards, M P; Pettitt, P B; Stiner, M C; Trinkaus, E

2001-05-22

New carbon and nitrogen stable isotope values for human remains dating to the mid-Upper Paleolithic in Europe indicate significant amounts of aquatic (fish, mollusks, and/or birds) foods in some of their diets. Most of this evidence points to exploitation of inland freshwater aquatic resources in particular. By contrast, European Neandertal collagen carbon and nitrogen stable isotope values do not indicate significant use of inland aquatic foods but instead show that they obtained the majority of their protein from terrestrial herbivores. In agreement with recent zooarcheological analyses, the isotope results indicate shifts toward a more broad-spectrum subsistence economy in inland Europe by the mid-Upper Paleolithic period, probably associated with significant population increases.

The Feynman-Y Statistic in Relation to Shift-Register Neutron Coincidence Counting: Precision and Dead Time

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

Croft, Stephen; Santi, Peter A.; Henzlova, Daniela

The Feynman-Y statistic is a type of autocorrelation analysis. It is defined as the excess variance-to-mean ratio, Y = VMR - 1, of the number count distribution formed by sampling a pulse train using a series of non-overlapping gates. It is a measure of the degree of correlation present on the pulse train with Y = 0 for Poisson data. In the context of neutron coincidence counting we show that the same information can be obtained from the accidentals histogram acquired using the multiplicity shift-register method, which is currently the common autocorrelation technique applied in nuclear safeguards. In the casemore » of multiplicity shift register analysis however, overlapping gates, either triggered by the incoming pulse stream or by a periodic clock, are used. The overlap introduces additional covariance but does not alter the expectation values. In this paper we discuss, for a particular data set, the relative merit of the Feynman and shift-register methods in terms of both precision and dead time correction. Traditionally the Feynman approach is applied with a relatively long gate width compared to the dieaway time. The main reason for this is so that the gate utilization factor can be taken as unity rather than being treated as a system parameter to be determined at characterization/calibration. But because the random trigger interval gate utilization factor is slow to saturate this procedure requires a gate width many times the effective 1/e dieaway time. In the traditional approach this limits the number of gates that can be fitted into a given assay duration. We empirically show that much shorter gates, similar in width to those used in traditional shift register analysis can be used. Because the way in which the correlated information present on the pulse train is extracted is different for the moments based method of Feynman and the various shift register based approaches, the dead time losses are manifested differently for these two approaches. The resulting estimates for the dead time corrected first and second order reduced factorial moments should be independent of the method however and this allows the respective dead time formalism to be checked. We discuss how to make dead time corrections in both the shift register and the Feynman approaches.« less

Impact on cognitive functions following gamma knife radiosurgery for cerebral arteriovenous malformations

PubMed Central

Raghunath, A.; Bennett, Niranjana; Arimappamagan, Arivazhagan; Bhat, Dhananjaya I.; Srinivas, Dwarakanath; Thennarasu, K.; Jamuna, R.; Somanna, Sampath

2016-01-01

Background: Radiosurgery is an alternative to surgical resection of arteriovenous malformation (AVM). Very few studies have addressed the concern of radiation injury to the brain and its attendant adverse effects on cognitive function. Materials and Methods: This prospective study included all patients who underwent gamma knife radiosurgery (GKRS) at our institute for cerebral AVM between 2006 and December 2008 (n = 34). All patients underwent neuropsychological evaluation before the procedure. Neuropsychological evaluation was repeated in eighteen patients 2 years following GKRS. Clinical outcome, AVM obliteration, and factors influencing outcome were analyzed in these eighteen patients. Results: Before GKRS, more than 50% had significant impairment of neuropsychological functions compared to normal population norms. 66.6% achieved the excellent radiosurgical outcome. At 2 years follow-up, patients showed varied improvement in neuropsychological function in various categories. Pretherapeutic median value for percentage perseverative responses was 26.5 and at follow-up, it reduced to 18.2 (P = 0.039). Set shifting improved in 11 patients (61.1%), remained same in 5 patients (27.7%), and deteriorated in two patients (11.1%). Patients with a higher Spetzler-Martin grade AVM demonstrated a significantly more favorable shift in follow-up test values for set shifting function (P = 0.021). Patients with postradiation imaging changes had lesser tendency to improve in neuropsychological performance at follow-up. Conclusions: GKRS has no clinically harmful effect on cognitive and neuropsychological functioning in patients with brain AVM. On the contrary, there is an improvement in majority of patients at 2 years following radiosurgery when nidus is obliterated. PMID:26933340

19F Magnetic resonance imaging of perfluorooctanoic acid encapsulated in liposome for biodistribution measurement.

PubMed

Kimura, Atsuomi; Narazaki, Michiko; Kanazawa, Yoko; Fujiwara, Hideaki

2004-07-01

The tissue distribution of perfluorooctanoic acid (PFOA), which is known to show unique biological responses, has been visualized in female mice by (19)F magnetic resonance imaging (MRI) incorporated with the recent advances in microimaging technique. The chemical shift selected fast spin-echo method was applied to acquire in vivo (19)F MR images of PFOA. The in vivo T(1) and T(2) relaxation times of PFOA were proven to be extremely short, which were 140 (+/- 20) ms and 6.3 (+/- 2.2) ms, respectively. To acquire the in vivo (19)F MR images of PFOA, it was necessary to optimize the parameters of signal selection and echo train length. The chemical shift selection was effectively performed by using the (19)F NMR signal of CF(3) group of PFOA without the signal overlapping because the chemical shift difference between the CF(3) and neighbor signals reaches to 14 kHz. The most optimal echo train length to obtain (19)F images efficiently was determined so that the maximum echo time (TE) value in the fast spin-echo sequence was comparable to the in vivo T(2) value. By optimizing these parameters, the in vivo (19)F MR image of PFOA was enabled to obtain efficiently in 12 minutes. As a result, the time course of the accumulation of PFOA into the mouse liver was clearly pursued in the (19)F MR images. Thus, it was concluded that the (19)F MRI becomes the effective method toward the future pharmacological and toxicological studies of perfluorocarboxilic acids.

The relative importance of fluid and kinetic frequency shifts of an electron plasma wave

NASA Astrophysics Data System (ADS)

Winjum, B. J.; Fahlen, J.; Mori, W. B.

2007-10-01

The total nonlinear frequency shift of a plasma wave including both fluid and kinetic effects is estimated when the phase velocity of the wave is much less than the speed of light. Using a waterbag or fluid model, the nonlinear frequency shift due to harmonic generation is calculated for an arbitrary shift in the wavenumber. In the limit where the wavenumber does not shift, the result is in agreement with previously published work [R. L. Dewar and J. Lindl, Phys. Fluids 15, 820 (1972); T. P. Coffey, Phys. Fluids 14, 1402 (1971)]. This shift is compared to the kinetic shift of Morales and O'Neil [G. J. Morales and T. M. O'Neil, Phys. Rev. Lett. 28, 417 (1972)] for wave amplitudes and values of kλD of interest to Raman backscatter of a laser driver in inertial confinement fusion.

Computational study of the shift of the G band of double-walled carbon nanotubes due to interlayer interactions

NASA Astrophysics Data System (ADS)

Popov, Valentin N.; Levshov, Dmitry I.; Sauvajol, Jean-Louis; Paillet, Matthieu

2018-04-01

The interactions between the layers of double-walled carbon nanotubes induce a measurable shift of the G bands relative to the isolated layers. While experimental data on this shift in freestanding double-walled carbon nanotubes has been reported in the past several years, a comprehensive theoretical description of the observed shift is still lacking. The prediction of this shift is important for supporting the assignment of the measured double-walled nanotubes to particular nanotube types. Here, we report a computational study of the G-band shift as a function of the semiconducting inner layer radius and interlayer separation. We find that with increasing interlayer separation, the G band shift decreases, passes through zero and becomes negative, and further increases in absolute value for the wide range of considered inner layer radii. The theoretical predictions are shown to agree with the available experimental data within the experimental uncertainty.

Economic design of control charts considering process shift distributions

NASA Astrophysics Data System (ADS)

Vommi, Vijayababu; Kasarapu, Rukmini V.

2014-09-01

Process shift is an important input parameter in the economic design of control charts. Earlier control chart designs considered constant shifts to occur in the mean of the process for a given assignable cause. This assumption has been criticized by many researchers since it may not be realistic to produce a constant shift whenever an assignable cause occurs. To overcome this difficulty, in the present work, a distribution for the shift parameter has been considered instead of a single value for a given assignable cause. Duncan's economic design model for chart has been extended to incorporate the distribution for the process shift parameter. It is proposed to minimize total expected loss-cost to obtain the control chart parameters. Further, three types of process shifts namely, positively skewed, uniform and negatively skewed distributions are considered and the situations where it is appropriate to use the suggested methodology are recommended.

The Advancement Value Chain: An Exploratory Model

ERIC Educational Resources Information Center

Leonard, Edward F., III

2005-01-01

Since the introduction of the value chain concept in 1985, several varying, yet virtually similar, value chains have been developed for the business enterprise. Shifting to higher education, can a value chain be found that links together the various activities of advancement so that an institution's leaders can actually look at the philanthropic…

Value Differences between Generations in China: A Study in Shanghai

ERIC Educational Resources Information Center

Sun, Jiaming; Wang, Xun

2010-01-01

The 1990 World Values Survey demonstrated that industrialization promotes a shift from traditional to secular-rational values. Drawing data from a sample survey of 2,350 respondents in Shanghai, this study examines the impact of social change on people's values in China. Specifically, we are interested in (1) are there significant differences in…

Shifting forest value orientations in the United States, 1980-2001: A computer content analysis

Treesearch

David N. Bengston; Trevor J. Webb; David P. Fan

2004-01-01

This paper examines three forest value orientations - clusters of interrelated values and basic beliefs about forests - that emerged from an analysis of the public discourse about forest planning, management, and policy in the United States. The value orientations include anthropocentric, biocentric, and moral/spiritual/aesthetic orientations toward forests. Computer...

Stress and salivary cortisol in emergency medical dispatchers: A randomized shifts control trial

PubMed Central

Bedini, Sarah; Braun, François; Weibel, Laurence; Aussedat, Michel; Pereira, Bruno; Dutheil, Frédéric

2017-01-01

Stress at work is a public health concern. Phone operators in emergency medical dispatch centers are particularly at risk. We aimed to demonstrate that the most stressful time for emergency medical dispatchers is the shift when they receive emergency incoming calls, with cortisol as a biomarker of stress. For each emergency medical dispatcher, we measured outcomes over a control day and during three types of shift: Incoming emergency call, Dispatch and Re-assessment. The pattern of shifts was randomized. Saliva was sampled every 15 minutes for 2 hours, i.e. 6 consecutive times, starting 15 minutes after the first life-and-death incoming emergency call between 2 and 5 pm during three types of shift. We measured saliva cortisol every 2 hours over a control day, from 7am to 9pm. Perceived stress was assessed by a visual analog scale. We recruited 22 phone operators aged 36.4+/-10.8 years old (14 women and 8 men). Cortisol values were higher during the Incoming emergency call shift than during the Dispatch (p = .04) and Re-assessment (p = .04) shifts. The increase in cortisol levels was greater in men than in women (p = .009). There were no differences between control values and those of the three shifts. The kinetics of cortisol increased with greater perceived stress overall (p < .001) and for each type of shift (Incoming emergency call, p = .02; Dispatch p = .03; Re-assessment: p < .001). The kinetics of cortisol in response to incoming emergency calls was greater when the call was an absolute emergency (p = .03), and also tended to further increase when a subsequent absolute incoming emergency call was received (p = 0.07). In conclusion, the incoming emergency call shift carries particular risk for dispatchers, who have greater perceived stress and a greater increase in cortisol levels. PMID:28505199

Stress and salivary cortisol in emergency medical dispatchers: A randomized shifts control trial.

PubMed

Bedini, Sarah; Braun, François; Weibel, Laurence; Aussedat, Michel; Pereira, Bruno; Dutheil, Frédéric

2017-01-01

Stress at work is a public health concern. Phone operators in emergency medical dispatch centers are particularly at risk. We aimed to demonstrate that the most stressful time for emergency medical dispatchers is the shift when they receive emergency incoming calls, with cortisol as a biomarker of stress. For each emergency medical dispatcher, we measured outcomes over a control day and during three types of shift: Incoming emergency call, Dispatch and Re-assessment. The pattern of shifts was randomized. Saliva was sampled every 15 minutes for 2 hours, i.e. 6 consecutive times, starting 15 minutes after the first life-and-death incoming emergency call between 2 and 5 pm during three types of shift. We measured saliva cortisol every 2 hours over a control day, from 7am to 9pm. Perceived stress was assessed by a visual analog scale. We recruited 22 phone operators aged 36.4+/-10.8 years old (14 women and 8 men). Cortisol values were higher during the Incoming emergency call shift than during the Dispatch (p = .04) and Re-assessment (p = .04) shifts. The increase in cortisol levels was greater in men than in women (p = .009). There were no differences between control values and those of the three shifts. The kinetics of cortisol increased with greater perceived stress overall (p < .001) and for each type of shift (Incoming emergency call, p = .02; Dispatch p = .03; Re-assessment: p < .001). The kinetics of cortisol in response to incoming emergency calls was greater when the call was an absolute emergency (p = .03), and also tended to further increase when a subsequent absolute incoming emergency call was received (p = 0.07). In conclusion, the incoming emergency call shift carries particular risk for dispatchers, who have greater perceived stress and a greater increase in cortisol levels.

Calculation of Ophthalmic Viscoelastic Device–Induced Focus Shift During Femtosecond Laser–Assisted Cataract Surgery

PubMed Central

de Freitas, Carolina P.; Cabot, Florence; Manns, Fabrice; Culbertson, William; Yoo, Sonia H.; Parel, Jean-Marie

2015-01-01

Purpose. To assess if a change in refractive index of the anterior chamber during femtosecond laser-assisted cataract surgery can affect the laser beam focus position. Methods. The index of refraction and chromatic dispersion of six ophthalmic viscoelastic devices (OVDs) was measured with an Abbe refractometer. Using the Gullstrand eye model, the index values were used to predict the error in the depth of a femtosecond laser cut when the anterior chamber is filled with OVD. Two sources of error produced by the change in refractive index were evaluated: the error in anterior capsule position measured with optical coherence tomography biometry and the shift in femtosecond laser beam focus depth. Results. The refractive indices of the OVDs measured ranged from 1.335 to 1.341 in the visible light (at 587 nm). The error in depth measurement of the refilled anterior chamber ranged from −5 to +7 μm. The OVD produced a shift of the femtosecond laser focus ranging from −1 to +6 μm. Replacement of the aqueous humor with OVDs with the densest compound produced a predicted error in cut depth of 13 μm anterior to the expected cut. Conclusions. Our calculations show that the change in refractive index due to anterior chamber refilling does not sufficiently shift the laser beam focus position to cause the incomplete capsulotomies reported during femtosecond laser–assisted cataract surgery. PMID:25626971

Shape-based retrieval of CNV regions in read coverage data.

PubMed

Hong, Sangkyun; Yoon, Jeehee; Hong, Dongwan; Lee, Unjoo; Kim, Baeksop; Park, Sanghyun

2014-01-01

This study proposes a novel copy number variation (CNV) detection method, CNV_shape, based on variations in the shape of the read coverage data which are obtained from millions of short reads aligned to a reference sequence. The proposed method carries out two transforms, mean shift transform and mean slope transform, to extract the shape of a CNV more precisely from real human data, which are vulnerable to experimental and biological noises. The mean shift transform is a procedure for gaining a preliminary estimation of the CNVs by statistically evaluating moving averages of given read coverage data. The mean slope transform extracts candidate CNVs by filtering out non-stationary sub-regions from each of the primary CNVs pre-estimated in the mean shift procedure. Each of the candidate CNVs is merged with neighbours depending on the merging score to be finally identified as a putative CNV, where the merging score is estimated by the ratio of the positions with non-zero values of the mean shift transform to the total length of the region including two neighbouring candidate CNVs and the interval between them. The proposed CNV detection method was validated experimentally with simulated data and real human data. The simulated data with coverage in the range of 1x to 10x were generated for various sampling sizes and p-values. Five individual human genomes were used as real human data. The results show that relatively small CNVs (> 1 kbp) can be detected from low coverage (> 1.7x) data. The results also reveal that, in contrast to conventional methods, performance improvement from 8.18 to 87.90% was achieved in CNV_shape. The outcomes suggest that the proposed method is very effective in reducing noises inherent in real data as well as in detecting CNVs of various sizes and types.

The Neurobiology of Reference-Dependent Value Computation

PubMed Central

De Martino, Benedetto; Kumaran, Dharshan; Holt, Beatrice; Dolan, Raymond J.

2009-01-01

A key focus of current research in neuroeconomics concerns how the human brain computes value. Although, value has generally been viewed as an absolute measure (e.g., expected value, reward magnitude), much evidence suggests that value is more often computed with respect to a changing reference point, rather than in isolation. Here, we present the results of a study aimed to dissociate brain regions involved in reference-independent (i.e., “absolute”) value computations, from those involved in value computations relative to a reference point. During functional magnetic resonance imaging, subjects acted as buyers and sellers during a market exchange of lottery tickets. At a behavioral level, we demonstrate that subjects systematically accorded a higher value to objects they owned relative to those they did not, an effect that results from a shift in reference point (i.e., status quo bias or endowment effect). Our results show that activity in orbitofrontal cortex and dorsal striatum track parameters such as the expected value of lottery tickets indicating the computation of reference-independent value. In contrast, activity in ventral striatum indexed the degree to which stated prices, at a within-subjects and between-subjects level, were distorted with respect to a reference point. The findings speak to the neurobiological underpinnings of reference dependency during real market value computations. PMID:19321780

Failure Processes in Embedded Monolayer Graphene under Axial Compression

PubMed Central

Androulidakis, Charalampos; Koukaras, Emmanuel N.; Frank, Otakar; Tsoukleri, Georgia; Sfyris, Dimitris; Parthenios, John; Pugno, Nicola; Papagelis, Konstantinos; Novoselov, Kostya S.; Galiotis, Costas

2014-01-01

Exfoliated monolayer graphene flakes were embedded in a polymer matrix and loaded under axial compression. By monitoring the shifts of the 2D Raman phonons of rectangular flakes of various sizes under load, the critical strain to failure was determined. Prior to loading care was taken for the examined area of the flake to be free of residual stresses. The critical strain values for first failure were found to be independent of flake size at a mean value of –0.60% corresponding to a yield stress up to -6 GPa. By combining Euler mechanics with a Winkler approach, we show that unlike buckling in air, the presence of the polymer constraint results in graphene buckling at a fixed value of strain with an estimated wrinkle wavelength of the order of 1–2 nm. These results were compared with DFT computations performed on analogue coronene/PMMA oligomers and a reasonable agreement was obtained. PMID:24920340

Added Value of Reliability to a Microgrid: Simulations of Three California Buildings

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

Marnay, Chris; Lai, Judy; Stadler, Michael

The Distributed Energy Resources Customer Adoption Model is used to estimate the value an Oakland nursing home, a Riverside high school, and a Sunnyvale data center would need to put on higher electricity service reliability for them to adopt a Consortium for Electric Reliability Technology Solutions Microgrid (CM) based on economics alone. A fraction of each building's load is deemed critical based on its mission, and the added cost of CM capability to meet it added to on-site generation options. The three sites are analyzed with various resources available as microgrid components. Results show that the value placed on highermore » reliability often does not have to be significant for CM to appear attractive, about 25 $/kWcdota and up, but the carbon footprint consequences are mixed because storage is often used to shift cheaper off-peak electricity to use during afternoon hours in competition with the solar sources.« less

Relevance of urinary 3-hydroxybenzo(a)pyrene and 1-hydroxypyrene to assess exposure to carcinogenic polycyclic aromatic hydrocarbon mixtures in metallurgy workers.

PubMed

Barbeau, Damien; Persoons, Renaud; Marques, Marie; Hervé, Claire; Laffitte-Rigaud, Gilbert; Maitre, Anne

2014-06-01

In metallurgy, workers are exposed to mixtures of polycyclic aromatic hydrocarbons (PAHs) in which some compounds are carcinogenic. Biomonitoring of PAH exposure has been performed by measuring urinary 1-hydroxypyrene (1-OHP), a metabolite of pyrene which is not carcinogenic. This study investigated the use of 3-hydroxybenzo(a)pyrene (3-OHBaP), a metabolite of benzo(a)pyrene (BaP) which is the main carcinogenic component in PAHs, to improve carcinogen exposure assessment. We included 129 metallurgy workers routinely exposed to PAHs during working hours. Urinary samples were collected at three sampling times at the beginning and at the end of the working week for 1-OHP and 3-OHBaP analyses. Workers in anode production showed greater exposure to both biomarkers than those in cathode or silicon production, with respectively, 71, 40, and 30% of 3-OHBaP concentrations exceeding the value of 0.4 nmol mol(-1) creatinine. No difference was observed between the 3-OHBaP levels found at the end of the penultimate workday shift and those at the beginning of the last workday shift. Within these plants, the 1-OHP/3-OHBaP ratios varied greatly according to the workers' activity and emission sources. Using linear regression between these two metabolites, the 1-OHP level corresponding to the guidance value for 3-OHBaP ranged from 0.7 to 2.4 µmol mol(-1) creatinine, depending on the industrial sector. This study emphasizes the interest of monitoring urinary 3-OHBaP at the end of the last workday shift when working week exposure is relatively steady, and the irrelevance of a single guideline value for 1-OHP when assessing occupational health risk. © The Author 2014. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

The OAE1a in Cuchía (Early Aptian, Spain): C and O geochemistry and global correlation

NASA Astrophysics Data System (ADS)

García-Mondéjar, Joaquín; Fernández-Mendiola, Pedro A.; Owen, Hugh G.

2015-12-01

C-isotopes, TOC and O geochemical data from the lower Aptian Cuchía section in the western Basque-Cantabrian basin (BCB) allow an accurate delimitation of the OAE1a-equivalent and its geochemical Menegattís segments, a detailed δ13Ccarb correlation with regional and interregional sections, and a high-resolution construction of TOC and bulk-rock δ18Ocarb curves and their interpretation. The δ13Ccarb values range from -2‰ and +4‰ (VPDB). They agree with previous data from the eastern BCB sections (Aralar) confirming the ammonite age of the OAE1a in the Basque-Cantabrian basin: Deshayesites forbesi, Deshayesites deshayesi, and Deshayesites deshayesi-Dufrenoyia furcata transition Zones. Interregional δ13Ccarb correlation with pelagic (Cismon, Italy, and Mid-Pacific Mountains, DSDP Site 463) and neritic (Roquefort-La Bédoule, France) core sections, reveals a common profile of a wide negative excursion characteristic of the OAE1a. It consists of a double trough separated by a flat relative maximum, with two negative spikes in the upper trough of neritic sections. TOC absolute values range from 0.12% to 1.37%. Segments of the TOC curve with persistent low values closely correspond with descending segments of the δ13Ccarb curve, and are attributed to lesser organic productivity in the BCB. Detailed bulk-rock δ18Ocarb data (-5.71‰ to -1.05 ‰ PDB) and variation curve show two main positive O-isotope shifts and three minor positive inflections, within a general negative trend characteristic of the OAE1a. The two major positive shifts correspond to both shallowing upwards sequences and the lowermost can be related to a eustatic sea level fall. Independent interregional correlation of the O-isotope shifts with C-isotopes supports their interpretation as punctuating colder events within a general warming trend.

Inner filter effect and the onset of concentration dependent red shift of synchronous fluorescence spectra.

PubMed

Tarai, Madhumita; Mishra, Ashok Kumar

2016-10-12

The phenomenon of concentration dependent red shift, often observed in synchronous fluorescence spectra (SFS) of monofluorophoric as well as multifluorophoric systems at high chromophore concentrations, is known to have good analytical advantages. This was previously understood in terms of large inner filter effect (IFE) through the introduction of a derived absorption spectral profile that closely corresponds to the SFS profile. Using representative monofluorophoric and multifluorophoric systems, it is now explained how the SF spectral maximum changes with concentration of the fluorophore. For dilute solutions of monofluorophores the maximum is unchanged as expected. It is shown here that the onset of red shift of SFS maximum of both the mono as well as the multifluorophoric systems must occur at the derived absorption spectral parameter value of 0.32 that corresponds to the absorbance value of 0.87. This value is unique irrespective of the nature of the fluorophore under study. For monofluorophoric systems, the wavelength of derived absorption spectral maximum and the wavelength of synchronous fluorescence spectral maximum closely correspond with each other in the entire concentration range. In contrast, for multifluorophoric systems like diesel and aqueous humic acid, large deviations were noted that could be explained as to be due to the presence of non-fluorescing chromophores in the system. This work bridges the entire fluorophore concentration range over which the red shift of SFS maximum sets in; and in the process it establishes the importance of the derived absorption spectral parameter in understanding the phenomenon of concentration dependent red shift of SFS maximum. Copyright © 2016 Elsevier B.V. All rights reserved.

Conformational analysis of the chemical shifts for molecules containing diastereotopic methylene protons

NASA Astrophysics Data System (ADS)

Borowski, Piotr

2012-01-01

Quantum chemistry SCF/GIAO calculations were carried out on a set of compounds containing diastereotopic protons. Five molecules, including recently synthesized 1,3-di(2,3-epoxypropoxy)benzene, containing the chiral or pro-chiral center and the neighboring methylene group, were chosen. The rotational averages (i.e. normalized averages with respect to the rotation about the torsional angle τ with the exponential energy weight at temperature T) calculated individually for each of the methylene protons in 1,3-di(2,3-epoxypropoxy)benzene differ by ca. 0.6 ppm, which is significantly less than the value calculated for the lowest energy conformer. This value turned out to be low enough to guarantee the proper ordering of theoretical chemical shifts, supporting the interpretation of the 1H NMR spectrum of this important compound. The rotational averages of chemical shifts for methylene protons for a given type of conformer are shown to be essentially equal to the Boltzmann averages (here, the population-weighted averages for the individual conformers representing minima on the E( τ) cross-section). The calculated Boltzmann averages in the representative conformational space may exhibit completely different ordering as compared to the chemical shifts calculated for the lowest-energy conformer. This is especially true in the case of molecules, for which no significant steric effects are present. In this case, only Boltzmann averages account for the experimental pattern of proton signals. In addition, better overall agreement with experiment (lower value of the root-mean-square deviation between calculated and measured chemical shifts) is typically obtained when Boltzmann averages are used.

Research Update: Enhancement of figure of merit for energy-harvesters based on free-standing epitaxial Pb(Zr0.52Ti0.48)0.99Nb0.01O3 thin-film cantilevers

NASA Astrophysics Data System (ADS)

Nguyen, Minh D.; Houwman, Evert; Dekkers, Matthijn; Schlom, Darrell; Rijnders, Guus

2017-07-01

All-oxide free-standing cantilevers were fabricated with epitaxial (001)-oriented Pb(Zr0.52Ti0.48)O3 (PZT) and Pb(Zr0.52Ti0.48)0.99Nb0.01O3 (PNZT) as piezoelectric layers and SrRuO3 electrodes. The ferroelectric and piezoelectric hysteresis loops were measured. From the zero-bias values, the figure-of-merits (FOMs) for piezoelectric energy harvesting systems were calculated. For the PNZT cantilever, an extremely large value FOM = 55 GPa was obtained. This very high value is due to the large shifts of the hysteresis loops such that the zero-bias piezoelectric coefficient e31f is maximum and the zero-bias dielectric constant is strongly reduced compared to the value in the undoped PZT device. The results show that by engineering the self-bias field the energy-harvesting properties of piezoelectric systems can be increased significantly.

Measurements in Flight of the Pressure Distribution on the Right Wing of a Pursuit-Type Airplane at Several Values of Mach Number

NASA Technical Reports Server (NTRS)

Clousing, Lawrence A; Turner, William N; Rolls, L Stewart

1946-01-01

Pressure-distribution measurements were made on the right wing of a pursuit-type airplane at values of Mach number up to 0.80. The results showed that a considerable portion of the lift was carried by components of the airplane other than the wings, and that the proportion of lift carried by the wings may vary considerably with Mach number, thus changing the bending moment at the wing root whether or not there is a shift in the lateral position of the center of pressure. It was also shown that the center of pressure does not necessarily move outward at high Mach numbers, even though the wing-thickness ratio decreases toward the wing tip. The wing pitching-moment coefficient increased sharply in a negative direction at a Mach lift-curve slope increased with Mach number up to values of above the critical value. Pressures inside the wing were small and negative.

Synthesis, Characterization and Photophysical Properties of Pyridine-Carbazole Acrylonitrile Derivatives

PubMed Central

Pérez-Gutiérrez, Enrique; Percino, M. Judith; Chapela, Víctor M.; Cerón, Margarita; Maldonado, José Luis; Ramos-Ortiz, Gabriel

2011-01-01

We synthesized three novel highly fluorescent compounds, 2-(2’-pyridyl)-3-(N-ethyl-(3’-carbazolyl))acrylonitrile, 2-(3”-pyridyl)-3-(N-ethyl-(3’-carbazolyl))acrylonitrile, and 2-(4-pyridyl)-3-(N-ethyl-(3’-carbazolyl))acrylonitrile by Knoevenagel condensation. The first two were synthesized without solvent in the presence of piperidine as a catalyst; the third was synthesized without a catalyst and with N,N-dimethylformamide as a solvent. In solution, the molar absorption coefficients showed absorptions at 380, 378, and 396 nm, respectively; in solid state, absorptions were at 398, 390, and 442 nm, respectively. The fluorescence emission was at 540, 540 and 604 nm, respectively, the 2-(4-pyridyl)-3-(N-ethyl-(3’-carbazolyl))acrylonitrile showed a red shift in the emission of 64 nm compared to the other two compounds. The fluorescence quantum yield for the compounds in powder form showed values of 0.05, 0.14, and 0.006, respectively; compared with the value measured for the Alq3 reference, 2-(3”-pyridyl)-3-(N-ethyl-(3’-carbazolyl))acrylonitrile had a lightly higher value. The third harmonic generation measurement for 2-(2’-pyridyl)-3-(N-ethyl-(3’-carbazolyl))acrylonitrile yielded a χ(3) value of 5.5 × 10−12 esu, similar to that reported for commercial polymers. PMID:28880006

Evaluating Effect of Albendazole on Trichuris trichiura Infection: A Systematic Review Article.

PubMed

Ahmadi Jouybari, Toraj; Najaf Ghobadi, Khadije; Lotfi, Bahare; Alavi Majd, Hamid; Ahmadi, Nayeb Ali; Rostami-Nejad, Mohammad; Aghaei, Abbas

2016-01-01

The aim of the study was assessment of defaults and conducted meta-analysis of the efficacy of single-dose oral albendazole against T. trichiura infection. We searched PubMed, ISI Web of Science, Science Direct, the Cochrane Central Register of Controlled Trials, and WHO library databases between 1983 and 2014. Data from 13 clinical trial articles were used. Each article was included the effect of single oral dose (400 mg) albendazole and placebo in treating two groups of patients with T. trichiura infection. For both groups in each article, sample size, the number of those with T. trichiura infection, and the number of those recovered following the intake of albendazole were identified and recorded. The relative risk and variance were computed. Funnel plot, Beggs and Eggers tests were used for assessment of publication bias. The random effect variance shift outlier model and likelihood ratio test were applied for detecting outliers. In order to detect influence, DFFITS values, Cook's distances and COVRATIO were used. Data were analyzed using STATA and R software. The article number 13 and 9 were outlier and influence, respectively. Outlier is diagnosed by variance shift of target study in inferential method and by RR value in graphical method. Funnel plot and Beggs test did not show the publication bias ( P =0.272). However, the Eggers test confirmed it ( P =0.034). Meta-analysis after removal of article 13 showed that relative risk was 1.99 (CI 95% 1.71 - 2.31). The estimated RR and our meta-analyses show that treatment of T. trichiura with single oral doses of albendazole is unsatisfactory. New anthelminthics are urgently needed.

Building on transformative learning and response shift theory to investigate health-related quality of life changes over time in individuals with chronic health conditions and disability.

PubMed

Barclay-Goddard, Ruth; King, Judy; Dubouloz, Claire-Jehanne; Schwartz, Carolyn E

2012-02-01

A major goal of treatment for people living with chronic illness or disability is self-management leading to optimized health-related quality of life. This change process has been described in the adult education literature as transformative learning, while in health-related quality of life research, response shift has emerged as a key concept. Response shift and transformative learning literature were reviewed, and the theoretical frameworks of the 2 concepts were compared and contrasted. Response shift is described as a change in internal standards, values, or definition of a construct (eg, health-related quality of life) over time, commonly seen in individuals with chronic illness. In the context of chronic illness, transformative learning is described as a complex process of personal change including beliefs, feelings, knowledge, and values. Transformative learning is often triggered by the diagnosis of a chronic illness. This results in a critical reflection of taken-for-granted assumptions and leads to new ways of thinking, influencing personal changes in daily living. Comparing the models of response shift and transformative learning in chronic illness, the catalyst in response shift appears comparable with the trigger in transformational learning; mechanisms to process of changing; and perceived quality of life to outcomes. Both transformative learning and response shift have much to offer health care providers in understanding the learning process for the person living with chronic illness or disability to optimize their quality of life. Suggestions for future research in response shift and transformative learning in individuals with chronic health conditions and disability are proposed. Copyright © 2012 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Characterization and frequency-thermal response of electrical properties of Cu nanoferrite prepared by sol-gel method

NASA Astrophysics Data System (ADS)

Moghadasi, Fatemeh S.; Daadmehr, Vahid; Kashfi, Monire

2016-10-01

In this paper, we have synthesized copper ferrite nanocrystals using sol-gel method. X-ray diffraction (XRD) analysis confirms that the ferrite has cubic spinal structure and shows Jahn-Teller effect. Also, scan electron microscope (SEM) image demonstrates that grains are nano size order. We showed that the dielectric properties are compatible with the Maxwell-Wagner model and phenomenological Koop's theory. Loss tangent and conductivity of the ferrite have been measured to have small values of 2.4 and 2×10-7 S/m, respectively at room temperature and at 12 Hz. Conductivity has been investigated in terms of localized hopping mechanism and good obedience of Jonscher's law was observed. Variation of activation energy was studied and showed a transition temperature of 443 °K. The electrical modulus shows relaxation of interfacial polarization with relaxation time of 0.318 ms at 24 °C and 15.9 μs at 72 °C. In Impedance spectroscopy, we observed the effects of grain and grain boundary. By increasing temperature, capacity and conduction would increase which show easier polarization process and a semiconducting behavior. Also, relaxation times are shifted to smaller values to represent increasing the electrons mobility.

Development and application of a modified dynamic time warping algorithm (DTW-S) to analyses of primate brain expression time series

PubMed Central

2011-01-01

Background Comparing biological time series data across different conditions, or different specimens, is a common but still challenging task. Algorithms aligning two time series represent a valuable tool for such comparisons. While many powerful computation tools for time series alignment have been developed, they do not provide significance estimates for time shift measurements. Results Here, we present an extended version of the original DTW algorithm that allows us to determine the significance of time shift estimates in time series alignments, the DTW-Significance (DTW-S) algorithm. The DTW-S combines important properties of the original algorithm and other published time series alignment tools: DTW-S calculates the optimal alignment for each time point of each gene, it uses interpolated time points for time shift estimation, and it does not require alignment of the time-series end points. As a new feature, we implement a simulation procedure based on parameters estimated from real time series data, on a series-by-series basis, allowing us to determine the false positive rate (FPR) and the significance of the estimated time shift values. We assess the performance of our method using simulation data and real expression time series from two published primate brain expression datasets. Our results show that this method can provide accurate and robust time shift estimates for each time point on a gene-by-gene basis. Using these estimates, we are able to uncover novel features of the biological processes underlying human brain development and maturation. Conclusions The DTW-S provides a convenient tool for calculating accurate and robust time shift estimates at each time point for each gene, based on time series data. The estimates can be used to uncover novel biological features of the system being studied. The DTW-S is freely available as an R package TimeShift at http://www.picb.ac.cn/Comparative/data.html. PMID:21851598

Development and application of a modified dynamic time warping algorithm (DTW-S) to analyses of primate brain expression time series.

PubMed

Yuan, Yuan; Chen, Yi-Ping Phoebe; Ni, Shengyu; Xu, Augix Guohua; Tang, Lin; Vingron, Martin; Somel, Mehmet; Khaitovich, Philipp

2011-08-18

Comparing biological time series data across different conditions, or different specimens, is a common but still challenging task. Algorithms aligning two time series represent a valuable tool for such comparisons. While many powerful computation tools for time series alignment have been developed, they do not provide significance estimates for time shift measurements. Here, we present an extended version of the original DTW algorithm that allows us to determine the significance of time shift estimates in time series alignments, the DTW-Significance (DTW-S) algorithm. The DTW-S combines important properties of the original algorithm and other published time series alignment tools: DTW-S calculates the optimal alignment for each time point of each gene, it uses interpolated time points for time shift estimation, and it does not require alignment of the time-series end points. As a new feature, we implement a simulation procedure based on parameters estimated from real time series data, on a series-by-series basis, allowing us to determine the false positive rate (FPR) and the significance of the estimated time shift values. We assess the performance of our method using simulation data and real expression time series from two published primate brain expression datasets. Our results show that this method can provide accurate and robust time shift estimates for each time point on a gene-by-gene basis. Using these estimates, we are able to uncover novel features of the biological processes underlying human brain development and maturation. The DTW-S provides a convenient tool for calculating accurate and robust time shift estimates at each time point for each gene, based on time series data. The estimates can be used to uncover novel biological features of the system being studied. The DTW-S is freely available as an R package TimeShift at http://www.picb.ac.cn/Comparative/data.html.

Reproductive dynamics of Pacific sanddab, Citharichthys sordidus, off the central coast of California

NASA Astrophysics Data System (ADS)

Lefebvre, Lyndsey S.; Payne, Amber M.; Field, John C.

2016-01-01

Female Pacific sanddab were collected from the Monterey Bay, California to describe their reproductive strategy and annual reproductive cycle, as well as to estimate length at maturity, fecundity, spawning fraction (SF), and spawning interval (SI). Captive females were held to examine degradation of spawning markers and confirmed the biological spawning capabilities of the species. The reproductive season extended from May through January, as determined through macroscopic and histological examination of ovaries. Oocyte development was asynchronous, and an indeterminate fecundity pattern was displayed. Absolute and relative batch fecundity values were variable (means = 6663 eggs and 54 eggs g- 1 somatic weight, respectively) and significantly related to maternal length. During the period of highest reproductive activity, SF ranged from 0.42 to 0.98, suggesting some females were spawning on a daily basis. Monthly SF and SI were related to length, with smaller females having a truncated season and lower SF compared to larger females. Lengths at 50% (119 mm) and 95% (149 mm) maturity showed a downward shift relative to the 1940s, though the magnitude and cause of this shift remain unknown. This study highlights the importance of considering demographic shifts and size-related dynamics when modeling a stock's reproductive potential.

Toward Quantifying the Electrostatic Transduction Mechanism in Carbon Nanotube Biomolecular Sensors

NASA Astrophysics Data System (ADS)

Lerner, Mitchell; Kybert, Nicholas; Mendoza, Ryan; Dailey, Jennifer; Johnson, A. T. Charlie

2013-03-01

Despite the great promise of carbon nanotube field-effect transistors (CNT FETs) for applications in chemical and biochemical detection, a quantitative understanding of sensor responses is lacking. To explore the role of electrostatics in sensor transduction, experiments were conducted with a set of similar compounds designed to adsorb onto the CNT FET via a pyrene linker group and take on a set of known charge states under ambient conditions. Acidic and basic species were observed to induce threshold voltage shifts of opposite sign, consistent with gating of the CNT FET by local charges due to protonation or deprotonation of the pyrene compounds by interfacial water. The magnitude of the gate voltage shift was controlled by the distance between the charged group and the CNT. Additionally, functionalization with an uncharged pyrene compound showed a threshold shift ascribed to its molecular dipole moment. This work illustrates a method for producing CNT FETs with controlled values of the turnoff gate voltage, and more generally, these results will inform the development of quantitative models for the response of CNT FET chemical and biochemical sensors. As an example, the results of an experiment detecting biomarkers of Lyme disease will be discussed in the context of this model.

Trophic shift in young-of-the-year Mugilidae during salt-marsh colonization.

PubMed

Lebreton, B; Richard, P; Guillou, G; Blanchard, G F

2013-04-01

This study investigated the trophic shift of young-of-the-year (YOY) thinlip grey mullet Liza ramada and golden grey mullet Liza aurata during their recruitment in a salt marsh located on the European Atlantic Ocean coast. Stable-isotope signatures (δ(13) C and δ(15) N) of the fishes followed a pattern, having enrichments in (13) C and (15) N with increasing fork length (LF ): δ(13) C in fishes < 30 mm ranged from -19.5 to -15.0‰, whereas in fishes > 30 mm δ(13) C ranged from -15.8 to -12.7‰, closer to the level in salt-marsh food resources. Large differences between the δ(15) N values of mugilids and those of food sources (6·0‰ on average) showed that YOY are secondary consumers, similar to older individuals, when feeding in the salt marsh. YOY mugilids shift from browsing on pelagic prey to grazing on benthic resources from the salt marsh before reaching 30 mm LF. The results highlight the role of European salt marshes as nurseries for juvenile mugilids. © 2013 The Authors. Journal of Fish Biology © 2013 The Fisheries Society of the British Isles.

Influence of shape and gradient refractive index in the accommodative changes of spherical aberration in nonhuman primate crystalline lenses.

PubMed

de Castro, Alberto; Birkenfeld, Judith; Maceo, Bianca; Manns, Fabrice; Arrieta, Esdras; Parel, Jean-Marie; Marcos, Susana

2013-09-11

To estimate changes in surface shape and gradient refractive index (GRIN) profile in primate lenses as a function of accommodation. To quantify the contribution of surface shape and GRIN to spherical aberration changes with accommodation. Crystalline lenses from 15 cynomolgus monkeys were studied in vitro under different levels of accommodation produced by a stretching system. Lens shape was obtained from optical coherence tomography (OCT) cross-sectional images. The GRIN was reconstructed with a search algorithm using the optical path measured from OCT images and the measured back focal length. The spherical aberration of the lens was estimated as a function of accommodation using the reconstructed GRIN and a homogeneous refractive index. The lens anterior and posterior radii of curvature decreased with increasing lens power. Both surfaces exhibited negative asphericities in the unaccommodated state. The anterior surface conic constant shifted toward less negative values with accommodation, while the value of the posterior remained constant. GRIN parameters remained constant with accommodation. The lens spherical aberration with GRIN distribution was negative and higher in magnitude than that with a homogeneous equivalent refractive index (by 29% and 53% in the unaccommodated and fully accommodated states, respectively). Spherical aberration with the equivalent refractive index shifted with accommodation toward negative values (-0.070 μm/diopter [D]), but the reconstructed GRIN shifted it farther (-0.124 μm/D). When compared with the lens with the homogeneous equivalent refractive index, the reconstructed GRIN lens has more negative spherical aberration and a larger shift toward more negative values with accommodation.

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

Collister, R.; Gwinner, G.; Tandecki, M.

We present the isotope shifts of the 7s 1/2 to 7p 1/2 transition for francium isotopes ²⁰⁶⁻²¹³Fr with reference to ²²¹Fr collected from two experimental periods. The shifts are measured on a sample of atoms prepared within a magneto-optical trap by a fast sweep of radio-frequency sidebands applied to a carrier laser. King plot analysis, which includes literature values for 7s 1/2 to 7p 3/2 isotope shifts, provides a field shift constant ratio of 1.0520(10) and a difference between the specific mass shift constants of 170(100) GHz amu between the D₁ and D₂ transitions, of sufficient precision to differentiate betweenmore » ab initio calculations.« less

A POSITIONAL DATA SYSTEM

DOEpatents

Forster, G.A.

1963-09-24

between master and slave synchros is described. A threephase a-c power source is connected to the stators of the synchros and an error detector is connected to the rotors of the synchros to measure the phasor difference therebetween. A phase shift network shifts the phase of one of the rotors 90 degrees and a demodulator responsive thereto causes the phasor difference signal of the rotors to shift phase 180 degrees whenever the 90 degree phase shifted signal goes negative. The phase shifted difference signal has a waveform which, with the addition of small values of resistance and capacitance, gives a substantially pure d-c output whose amplitude and polarity is proportional to the magnitude and direction of the difference in the angular positions of the synchro's rotors. (AEC)

Inconsistent Range Shifts within Species Highlight Idiosyncratic Responses to Climate Warming

PubMed Central

Gibson-Reinemer, Daniel K.; Rahel, Frank J.

2015-01-01

Climate in part determines species’ distributions, and species’ distributions are shifting in response to climate change. Strong correlations between the magnitude of temperature changes and the extent of range shifts point to warming temperatures as the single most influential factor causing shifts in species’ distributions species. However, other abiotic and biotic factors may alter or even reverse these patterns. The importance of temperature relative to these other factors can be evaluated by examining range shifts of the same species in different geographic areas. When the same species experience warming in different geographic areas, the extent to which they show range shifts that are similar in direction and magnitude is a measure of temperature’s importance. We analyzed published studies to identify species that have documented range shifts in separate areas. For 273 species of plants, birds, mammals, and marine invertebrates with range shifts measured in multiple geographic areas, 42-50% show inconsistency in the direction of their range shifts, despite experiencing similar warming trends. Inconsistency of within-species range shifts highlights how biotic interactions and local, non-thermal abiotic conditions may often supersede the direct physiological effects of temperature. Assemblages show consistent responses to climate change, but this predictability does not appear to extend to species considered individually. PMID:26162013

Beyond positivist ecology: toward an integrated ecological ethics.

PubMed

Norton, Bryan G

2008-12-01

A post-positivist understanding of ecological science and the call for an "ecological ethic" indicate the need for a radically new approach to evaluating environmental change. The positivist view of science cannot capture the essence of environmental sciences because the recent work of "reflexive" ecological modelers shows that this requires a reconceptualization of the way in which values and ecological models interact in scientific process. Reflexive modelers are ecological modelers who believe it is appropriate for ecologists to examine the motives for their choices in developing models; this self-reflexive approach opens the door to a new way of integrating values into public discourse and to a more comprehensive approach to evaluating ecological change. This reflexive building of ecological models is introduced through the transformative simile of Aldo Leopold, which shows that learning to "think like a mountain" involves a shift in both ecological modeling and in values and responsibility. An adequate, interdisciplinary approach to ecological valuation, requires a re-framing of the evaluation questions in entirely new ways, i.e., a review of the current status of interdisciplinary value theory with respect to ecological values reveals that neither of the widely accepted theories of environmental value-neither economic utilitarianism nor intrinsic value theory (environmental ethics)-provides a foundation for an ecologically sensitive evaluation process. Thus, a new, ecologically sensitive, and more comprehensive approach to evaluating ecological change would include an examination of the metaphors that motivate the models used to describe environmental change.

Absolute vibrational numbering from isotope shifts in fragmentary spectroscopic data

NASA Astrophysics Data System (ADS)

Pashov, A.; Kowalczyk, P.; Jastrzebski, W.

2018-05-01

We discuss application of the isotope effect to establish the absolute vibrational numbering in electronic states of diatomic molecules. This is illustrated by examples of states with potential energy curves of both regular and irregular shape, with one or two potential minima. The minimum number of spectroscopic data (either term values or spectral line positions) necessary to provide a unique numbering is considered. We show that at favourable conditions just four term energies (or spectral lines) in one isotopologue and one term energy in the other suffice.

CRRES microelectronic test chip orbital data. II

NASA Technical Reports Server (NTRS)

Soli, G. A.; Blaes, B. R.; Buehler, M. G.; Ray, K.; Lin, Y.-S.

1992-01-01

Data from a MOSFET matrix on two JPL (CIT Jet Propulsion Laboratory) CRRES (Combined Release and Radiation Effects Satellite) chips, each behind different amounts of shielding, are presented. Space damage factors are nearly identical to ground test values for pMOSFETs. The results from neighboring rows of MOSFETs show similar radiation degradation. The SRD (Space Radiation Dosimeter) is used to measure the total dose accumulated by the JPL chips. A parameter extraction algorithm that does not underestimate threshold voltage shifts is used. Temperature effects are removed from the MOSFET data.

Embedding spiritual value through science learning

NASA Astrophysics Data System (ADS)

Johan, H.; Suhandi, A.; Wulan, A. R.; Widiasih; Ruyani, A.; Karyadi, B.; Sipriyadi

2018-05-01

The purpose of this study was to embed spiritual value through science learning program especially earth planet. Various phenomena in earth planet describe a divinity of super power. This study used quasi experimental method with one group pre-test-post-test design. Convenience sampling was conducted in this study. 23 pre-service physics teacher was involved. Pre-test and post-test used a questionnaire had been conducted to collected data of spiritual attitude. Open ended question had been utilized at post-test to collected data. A fourth indicators of spiritual value related to divinity of God was used to embed spiritual value. The results show a shifted of students’ awareness to divinity of God. Before implementing the earth planet learning, 85.8% of total students strongly agree that learning activity embed spiritual value while after learning process, it increased be 93.4%. After learning earth planet, it known that students’ spiritual value was influenced by character of earth planet concept which unobservable and media visual which display each incredible phenomena process in our earth planet. It can be concluded that spiritual value can be embedded through unobservable phenomena of during learning earth planet process.

Cross-shift peak expiratory flow changes are unassociated with respirable coal dust exposure among South African coal miners.

PubMed

Naidoo, Rajen N; Robins, Thomas G; Becklake, Margaret; Seixas, Noah; Thompson, Mary Lou

2007-12-01

The objectives of this study were to determine whether cross-shift changes in peak expiratory flow rate (PEFR) were related to respirable dust exposure in South African coalminers. Fifty workers were randomly selected from a cohort of 684 miners from 3 bituminous coalmines in Mpumalanga, South Africa. Peak expiratory efforts were measured prior to the commencement of the shift, and at the end of the shift on at least two occasions separated by at least 2 weeks, with full shift personal dust sampling being conducted on each occasion for each participant. Interviews were conducted, work histories were obtained and cumulative exposure estimates were constructed. Regression models examined the associations of cross-shift changes in PEFR with current and cumulative exposure, controlling for shift, smoking and past history of tuberculosis. There were marginal differences in cross-shift PEFR (ranging from 0.1 to 2 L/min). Linear regression analyses showed no association between cross-shift change in PEFR and current or cumulative exposure. The specific shift worked by participants in the study showed no effect. Our study showed no association between current respirable dust exposure and cross-shift changes in PEFR. There was a non-significant protective effect of cumulative dust exposure on the outcome, suggesting the presence of a "healthy worker survivor effect" in this data.

Electrostatic Ion-Cyclotron Waves in Magnetospheric Plasmas: Non-Local Aspects.

DTIC Science & Technology

1983-10-14

moving observer will see a Doppler shifted frequency --- S where is the velocity vector of the observer (satellite) and k is the wave vector. Since k...direction) will not see any Doppler -shift, irrespective of the size of ky . Such a statement could not be made in the purely local theory, since there...a local theory, a wide range of Doppler shifts would be produced, from -kivs to +kivs, since the maximum value of kx is k1. Some of the observations

Nuclear magnetic resonance, vibrational spectroscopic studies, physico-chemical properties and computational calculations on (nitrophenyl) octahydroquinolindiones by DFT method.

PubMed

Pasha, M A; Siddekha, Aisha; Mishra, Soni; Azzam, Sadeq Hamood Saleh; Umapathy, S

2015-02-05

In the present study, 2'-nitrophenyloctahydroquinolinedione and its 3'-nitrophenyl isomer were synthesized and characterized by FT-IR, FT-Raman, (1)H NMR and (13)C NMR spectroscopy. The molecular geometry, vibrational frequencies, (1)H and (13)C NMR chemical shift values of the synthesized compounds in the ground state have been calculated by using the density functional theory (DFT) method with the 6-311++G (d,p) basis set and compared with the experimental data. The complete vibrational assignments of wave numbers were made on the basis of potential energy distribution using GAR2PED programme. Isotropic chemical shifts for (1)H and (13)C NMR were calculated using gauge-invariant atomic orbital (GIAO) method. The experimental vibrational frequencies, (1)H and (13)C NMR chemical shift values were found to be in good agreement with the theoretical values. On the basis of vibrational analysis, molecular electrostatic potential and the standard thermodynamic functions have been investigated. Copyright © 2014 Elsevier B.V. All rights reserved.

Color vision of the coelacanth (Latimeria chalumnae) and adaptive evolution of rhodopsin (RH1) and rhodopsin-like (RH2) pigments.

PubMed

Yokoyama, S

2000-01-01

The coelacanth, a "living fossil," lives at a depth of about 200 m near the coast of the Comoros archipelago in the Indian Ocean and receives only a narrow range of light at about 480 nm. To see the entire range of "color" the Comoran coelacanth appears to use only rod-specific RH1 and cone-specific RH2 visual pigments, with the optimum light sensitivities (lambda max) at 478 nm and 485 nm, respectively. These blue-shifted lambda max values of RH1 and RH2 pigments are fully explained by independent double amino acid replacements E122Q/A292S and E122Q/M207L, respectively. More generally, currently available mutagenesis experiments identify only 10 amino acid changes that shift the lambda max values of visual pigments more than 5 nm. Among these, D83N, E1220, M207L, and A292S are associated strongly with the adaptive blue shifts in the lambda max values of RH1 and RH2 pigments in vertebrates.

Ferns and fires: Experimental charring of ferns compared to wood and implications for paleobiology, paleoecology, coal petrology, and isotope geochemistry

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

McParland, L.C.; Collinson, M.E.; Scott, A.C.

We report the effects of charring on the ferns Osmunda, Pteridium, and Matteucia with coniferous wood (Sequoia) for comparison. Like charred wood, charred ferns shrink, become black and brittle with a silky sheen, and retain three-dimensional cellular structure. Ferns yield recognizable charcoal (up to 800{sup o}C) that could potentially survive in the fossil record enabling reconstruction of ancient fire-prone vegetation containing ferns. Charred fossils of herbaceous ferns would indicate surface fires. Like charred wood, cell-wall layers of charred ferns homogenize, and their reflectance values increase with rising temperature. Charcoalified fragments of thick-walled cells from conifer wood or fern tissues aremore » indistinguishable and so cannot be used to infer the nature of source vegetation. Charred conifer wood and charred fern tissues show a relationship between mean random reflectance and temperature of formation and can be used to determine minimum ancient fire temperatures. Charred fern tissues consistently have significantly more depleted {delta}{sup 13}C values ({le} 4 parts per thousand) than charred wood. Therefore, if an analysis of {delta} {sup 13}C through time included fern charcoal among a succession of wood charcoals, any related shifts in {delta} {sup 13}C could be misinterpreted as atmospheric changes or misused as isotope stratigraphic markers. Thus, charcoals of comparable botanical origin and temperatures of formation should be used in order to avoid misinterpretations of shifts in {delta}{sup 13}C values.« less

Experimental (13C NMR, 1H NMR, FT-IR, single-crystal X-ray diffraction) and DFT studies on 3,4-bis(isoproylamino)cyclobut-3-ene-1,2-dione.

PubMed

Süleymanoğlu, Nevin; Ustabaş, Reşat; Alpaslan, Yelda Bingöl; Eyduran, Fatih; Ozyürek, Cengiz; Iskeleli, Nazan Ocak

2011-12-01

In this work, 3,4-bis(isoproylamino)cyclobut-3-ene-1,2-dione C(10)H(16)N(2)O(2) (I), was synthesized and characterized by (13)C NMR, (1)H NMR, FT-IR, UV-vis spectroscopy and single-crystal X-ray diffraction. DFT method with 6-31G(d,p) basis set has been used to calculate the optimized geometrical parameters, atomic charges, vibrational frequencies and chemical shift values. The calculated vibrational frequencies and chemical shift values are compared with experimental FT-IR and NMR spectra. The results of the calculation shows good agreement between experimental and calculated values of the compound I. The existence of N-H⋯O type intermolecular ve C-H⋯O type intramolecular hydrogen bonds can be deduced from differences between experimental and calculated results of FT-IR and NMR. In addition, the molecular electrostatic potential map and frontier molecular orbitals and electronic absorption spectra were performed at B3LYP/6-31G(d,p) level of theory. HOMO-LUMO electronic transition of 4.90 eV are derived from the contribution of the bands π→π* and n→π* The spectral results obtained from FT-IR, NMR and X-ray of I revealed that the compound I is in predominantly enamine tautomeric form, which was supported by DFT calculations. Copyright © 2011 Elsevier B.V. All rights reserved.

Conditional heteroscedasticity as a leading indicator of ecological regime shifts.

PubMed

Seekell, David A; Carpenter, Stephen R; Pace, Michael L

2011-10-01

Regime shifts are massive, often irreversible, rearrangements of nonlinear ecological processes that occur when systems pass critical transition points. Ecological regime shifts sometimes have severe consequences for human well-being, including eutrophication in lakes, desertification, and species extinctions. Theoretical and laboratory evidence suggests that statistical anomalies may be detectable leading indicators of regime shifts in ecological time series, making it possible to foresee and potentially avert incipient regime shifts. Conditional heteroscedasticity is persistent variance characteristic of time series with clustered volatility. Here, we analyze conditional heteroscedasticity as a potential leading indicator of regime shifts in ecological time series. We evaluate conditional heteroscedasticity by using ecological models with and without four types of critical transition. On approaching transition points, all time series contain significant conditional heteroscedasticity. This signal is detected hundreds of time steps in advance of the regime shift. Time series without regime shifts do not have significant conditional heteroscedasticity. Because probability values are easily associated with tests for conditional heteroscedasticity, detection of false positives in time series without regime shifts is minimized. This property reduces the need for a reference system to compare with the perturbed system.

Plasticizers effect on native biodegradable package materials

NASA Astrophysics Data System (ADS)

Cozar, Onuc; Cioica, Nicolae; Coţa, Constantin; Nagy, Elena Mihaela; Fechete, Radu

2017-01-01

Changes in intensity of some IR and Raman bands suggest the plasticizing - antiplasticizing effects of water and glycerol contents and a small increase of amorphous/crystalline ratio, too. The nuclear magnetic relaxation data show that the amorphous/crystalline ratio depends on amylose/amylopectin mobility and also by the place of their polymer chain segments. Thus the distributions of spin-spin (T2) relaxation times and the shift toward higher values of some T2 characteristic peaks show that the increasing of water and glycerol content in the starch package materials lead to the more mobile amylose and amylopectin polymer chain segments and the prevalence of amorphous regions in the prepared native corn starch samples.

Accurate control of a liquid-crystal display to produce a homogenized Fourier transform for holographic memories.

PubMed

Márquez, Andrés; Gallego, Sergi; Méndez, David; Alvarez, Mariela L; Fernández, Elena; Ortuño, Manuel; Neipp, Cristian; Beléndez, Augusto; Pascual, Inmaculada

2007-09-01

We show an accurate procedure to obtain a Fourier transform (FT) with no dc term using a commercial twisted-nematic liquid-crystal display. We focus on the application to holographic storage of binary data pages, where a drastic decrease of the dc term in the FT is highly desirable. Two different codification schemes are considered: binary pi radians phase modulation and hybrid ternary modulation. Any deviation in the values of the amplitude and phase shift generates the appearance of a strong dc term. Experimental results confirm that the calculated configurations provide a FT with no dc term, thus showing the effectiveness of the proposal.

Regime shifts and ecological catastrophes in a model of plankton-oxygen dynamics under the climate change.

PubMed

Petrovskii, Sergei; Sekerci, Yadigar; Venturino, Ezio

2017-07-07

It is estimated that more than a half of the total atmospheric oxygen is produced in the oceans due to the photosynthetic activity of phytoplankton. Any significant decrease in the net oxygen production by phytoplankton is therefore likely to result in the depletion of atmospheric oxygen and in a global mass mortality of animals and humans. In its turn, the rate of oxygen production is known to depend on water temperature and hence can be affected by the global warming. We address this problem theoretically by considering a model of a coupled plankton-oxygen dynamics where the rate of oxygen production slowly changes with time to account for the ocean warming. We show that, when the temperature rises sufficiently high, a regime shift happens: the sustainable oxygen production becomes impossible and the system's dynamics leads to fast oxygen depletion and plankton extinction. We also consider a scenario when, after a certain period of increase, the temperature is set on a new higher yet apparently safe value, i.e. before the oxygen depletion disaster happens. We show that in this case the system dynamics may exhibit a long-term quasi-sustainable dynamics that can still result in an ecological disaster (oxygen depletion and mass extinctions) but only after a considerable period of time. Finally, we discuss the early warning signals of the approaching regime shift resulting in the disaster. Copyright © 2017 Elsevier Ltd. All rights reserved.

Operation Valuation: Teaching Pricing Concepts in an Experiential Environment

ERIC Educational Resources Information Center

Mills, Adam J.; Treen, Emily

2016-01-01

Although marketing education has seen a dramatic shift toward hands-on, experiential learning in recent years, the teaching of pricing has fallen behind complementary elements of the marketing mix in pedagogical execution. Although the teaching of pricing has shifted focus from economic-based models to value-based pricing in theory, available…

Breath carbon stable isotope ratios identify changes in energy balance and substrate utilization in humans

USDA-ARS?s Scientific Manuscript database

Rapid detection of shifts in substrate utilization and energy balance would provide a compelling biofeedback tool to enable individuals to lose weight. In a pilot study, we tested whether the natural abundance of exhaled carbon stable isotope ratios (breath d13C values) reflects shifts between negat...

Wireless Intrusion Detection

DTIC Science & Technology

2007-03-01

32 4.4 Algorithm Pseudo - Code ...................................................................................34 4.5 WIND Interface With a...difference estimates of xc temporal derivatives, or by using a polynomial fit to the previous values of xc. 34 4.4 ALGORITHM PSEUDO - CODE Pseudo ...Phase Shift Keying DQPSK Differential Quadrature Phase Shift Keying EVM Error Vector Magnitude FFT Fast Fourier Transform FPGA Field Programmable

Strategies for Multicultural Management: Communication and a Common Set of Values

ERIC Educational Resources Information Center

Castaneda, Mario E.; Bateh, Justin

2013-01-01

In the last 30 years, there has been a shift towards using multicultural strategies. The constant shifts taking place in multi-ethnic, multicultural, and multinational workforces indicate that both administrators of these organizations and higher education practices must evolve to adapt to needs for changing skill sets. In the future,…

Circadian Disruptions of Heart Rate Variability among Weekly Consecutive-12-hour 2 Shift Workers in the Automobile Factory in Korea.

PubMed

Son, Mia; Sung, Juhon; Yum, Myunggul; Kong, Jung Ok; Lee, Hye Un; Kim, In A; Kim, Jung Yeon

2004-05-01

The objective of this study is to compare the circadian patterns of heart rate variability assessed by 24-hour ambulatory electrocardiographic (ECG) recordings during day shift and night shift among the workers in the 5 days-concecutive- 12-hour shift in an automobile factory in Korea. The study population consisted 300 workers, who were randomly selected among the 8700 total workers in one car factory. To analyse circadian variation, the 24-hour ECG recordings (Marquette) were measured during day shift (08: 00-20: 00 h) and night shift (20: 00-08: 00 h). Analysis was performed for all time and frequency domain measures of HRV. 233 workers completed taking 24-hour ECG recordings. This study shows that the 24 hourcircadian variation mainly follows work/sleep cycle rather than day/night cycle among shift workers. This study also shows that among the night shift, the circadian variation between work and sleep cycle decreased compared to the work/sleep cycle among day shift workers. All time and frequency domain parameters (except LF/HF ratio) show significantly different between work and sleep in the day shift and night shift. These changes in heart rate variability circadian rhythms reflect significant reductions in cardiac parasympathetic activity with the most marked reduction in normal vagal activity among the shift workers. Especially, it suggests the circadian rhytm has blunted among the night workers. The quantification of the circadian variation in HRV can be a surrogates of workers' potential health risk, as well as suggests possible mechanisms through which the shift works compromise workers' health.

Adjusting to climate: acclimation, adaptation, and developmental plasticity in physiological traits of a tropical rainforest lizard.

PubMed

Llewelyn, John; Macdonald, Stewart L; Moritz, Craig; Martins, Felipe; Hatcher, Amberlee; Phillips, Ben L

2018-01-09

The impact of climate change may be felt most keenly by tropical ectotherms. In these taxa, it is argued, thermal specialisation means a given shift in temperature will have a larger effect on fitness. For species with limited dispersal ability, the impact of climate change depends on the capacity for their climate-relevant traits to shift. Such shifts can occur through genetic adaptation, various forms of plasticity, or a combination of these processes. Here we assess the extent and causes of shifts in seven physiological traits in a tropical lizard, the rainforest sunskink (Lampropholis coggeri). Two populations were sampled that differ from each other in both climate and physiological traits. We compared trait values in each animal soon after field collection versus following acclimation to laboratory conditions. We also compared trait values between populations in: (1) recently field-collected animals, (2) the same animals following laboratory acclimation, and (3) the laboratory-reared offspring of these animals. Our results reveal high trait lability, driven primarily by acclimation and local adaptation. By contrast, developmental plasticity, resulting from incubation temperature, had little-to-no effect on most traits. These results suggest that, while specialised, tropical ectotherms may be capable of rapid shifts in climate-relevant traits. This article is protected by copyright. All rights reserved.

Plasmon excitations in doped square-lattice atomic clusters

NASA Astrophysics Data System (ADS)

Wang, Yaxin; Yu, Ya-Bin

2017-12-01

Employing the tight-binding model, we theoretically study the properties of the plasmon excitations in doped square-lattice atomic clusters. The results show that the dopant atoms would blur the absorption spectra, and give rise to extra plasmon resonant peaks as reported in the literature; however, our calculated external-field induced oscillating charge density shows that no obvious evidences indicate the so-called local mode of plasmon appearing in two-dimensional-doped atomic clusters, but the dopants may change the symmetry of the charge distribution. Furthermore, we show that the disorder of the energy level due to dopant makes the absorption spectrum has a red- or blue-shift, which depends on the position of impurities; disorder of hopping due to dopant makes a blue- or red-shift, a larger (smaller) hopping gives a blue-shift (red-shift); and a larger (smaller) host-dopant and dopant-dopant intersite coulomb repulsion induces a blue-shift (red-shift).

Innovation, productivity, and pricing: Capturing value from precision medicine technology in Canada.

PubMed

Emery, J C Herbert; Zwicker, Jennifer D

2017-07-01

For new technology and innovation such as precision medicine to become part of the solution for the fiscal sustainability of Canadian Medicare, decision-makers need to change how services are priced rather than trying to restrain emerging technologies like precision medicine for short-term cost savings. If provincial public payers shift their thinking to be public purchasers, value considerations would direct reform of the reimbursement system to have prices that adjust with technologically driven productivity gains. This strategic shift in thinking is necessary if Canadians are to benefit from the promised benefits of innovations like precision medicine.

From evaporated seawater to uranium-mineralizing brines: Isotopic and trace element study of quartz-dolomite veins in the Athabasca system

NASA Astrophysics Data System (ADS)

Richard, Antonin; Boulvais, Philippe; Mercadier, Julien; Boiron, Marie-Christine; Cathelineau, Michel; Cuney, Michel; France-Lanord, Christian

2013-07-01

Stable isotope (O, H, C), radiogenic isotope (Sr, Nd) and trace element analyses have been applied to quartz-dolomite veins and their uranium(U)-bearing fluid inclusions associated with Proterozoic unconformity-related UO2 (uraninite) ores in the Athabasca Basin (Canada) in order to trace the evolution of pristine evaporated seawater towards U-mineralizing brines during their migration through sediments and basement rocks. Fluid inclusion data show that quartz and dolomite have precipitated from brines of comparable chemistry (excepted for relatively small amounts of CO2 found in dolomite-hosted fluid inclusions). However, δ18O values of quartz veins (δ18O = 11‰ to 18‰) and dolomite veins (δ18O = 13‰ to 24‰) clearly indicate isotopic disequilibrium between quartz and dolomite. Hence, it is inferred that this isotopic disequilibrium primarily reflects a decrease in temperature between the quartz stage (˜180 °C) and the dolomite stage (˜120 °C). The δ13C values of CO2 dissolved in dolomite-hosted fluid inclusions (δ13C = -30‰ to -4‰) and the δ13C values of dolomite (δ13C = -23.5‰ to -3.5‰) indicate that the CO2 dissolved in the mineralizing brines originated from brine-graphite interactions in the basement. The resulting slight increase in the fluid partial pressure of CO2 (pCO2) may have triggered dolomite precipitation instead of quartz. δ18O values of quartz veins and previously published δ18O values of the main alteration minerals around the U-ores (illite, chlorite and tourmaline) show that quartz and alteration minerals were isotopically equilibrated with the same fluid at ˜180 °C. The REE concentrations in dolomite produce PAAS-normalized patterns that show some similarities with that of UO2 and are clearly distinct from that of the other main REE-bearing minerals in these environments (monazite, zircon and aluminum phosphate-sulfate (APS) minerals). The radiogenic isotope compositions of dolomite (87Sr/86Sri = 0.7053 to 0.7161 and ɛNd(t) = -8.8 to -20.3) differ from one deposit to another, reflecting both heterogeneity in the basement geology and variable preservation of the original composition of brines. The previously published 87Sr/86Sri and ɛNd(t) values of UO2 compare with the most evolved dolomites, i.e. dolomites precipitated from brines that exchanged the most with the basement. This reinforces a close genetic link between dolomites and UO2 deposition and implies that UO2 deposition occurred in a cooling system during the transition from quartz to dolomite formation. The δ18O and δD values of the mineralizing brines (δ18O = -1‰ to 8‰ and δD = -150‰ to -50‰) are considerably shifted from that of their theoretical original values acquired during evaporation of seawater (δ18O = ˜-3‰ and δD = ˜-40‰). The positive δ18O shift is explained by protracted fluid-rock interaction within the basin and basement rocks. The negative δD shift is attributed to incomplete mixing between the U-mineralizing brines and low δD water. This low δD water was likely produced during the abiogenic synthesis of bitumen by Fisher-Tropsch-like reactions involving CO2 derived from brine-graphite interaction in the basement, and radiolytic H2. The resulting low δD brines have been equilibrated with alteration minerals. This may explain why some alteration minerals yield anomalously low δD values whose significance has long been debated.

Thermal stress in North Western Australian iron ore mining staff.

PubMed

Peiffer, Jeremiah J; Abbiss, Chris R

2013-05-01

Demand for Australian mined iron ore has increased employment within this sector, thus exposing increased numbers of workers to the harsh Australian climate. This study examined the influence of hot (>30°C wet bulb globe temperature) environmental temperatures, consistent with working in North Western Australia, on iron ore mining staff. Core temperature, hydration status, perceived exertion, mood, and fatigue state were measured in 77 participants at three time points (pre-, mid-, and post-shift) during a normal 12-h shift at an open-cut iron ore mining/processing site (n = 31; Site1) and an iron ore processing/shipping site (n = 46; Site2). A significant effect for time was observed for core temperature with greater mean core temperatures measured mid-shift (37.5±0.4°C) and post-shift (37.6±0.3°C) compared with pre-shift values (37.0±0.5°C). All mean core temperature measures were lower than ISO7933 thresholds (38°C) for thermal safety. Mean hydration measures [urine-specific gravity (USG)] were greater at Site1 (1.029±0.006) compared with those at Site2 (1.021±0.007). Furthermore, both pre- and post-shift measures from Site1 and the post-shift measures from Site2 were greater than the threshold for dehydration (USG = 1.020). No differences were observed for mood or perceived exertion over time; however, measures of fatigue state were greater post-shift compared with pre- and mid-shift values for both sites. Our findings indicate that the majority of mine workers in North Western Australia are able to regulate work rate in hot environments to maintain core temperatures below ISO safety guidelines; however, 22% of workers reached or exceeded the safety guidelines, warranting further investigation. Furthermore, hydration practices, especially when off-work, appear inadequate and could endanger health and safety.

Updating the "Risk Index": A systematic review and meta-analysis of occupational injuries and work schedule characteristics.

PubMed

Fischer, Dorothee; Lombardi, David A; Folkard, Simon; Willetts, Joanna; Christiani, David C

2017-01-01

Fatigue is a major risk factor for occupational 'accidents' and injuries, and involves dimensions of physical, mental, and muscular fatigue. These dimensions are largely influenced by temporal aspects of work schedules. The "Risk Index" combines four fatigue-related components of work schedules to estimate occupational 'accident' and injury risk based on empirical trends: shift type (morning, afternoon/evening, night), length and consecutive number, and on-shift rest breaks. Since its first introduction in 2004, several additional studies have been published that allow the opportunity to improve the internal and external validity of the "Risk Index". Thus, we updated the model's estimates by systematically reviewing the literature and synthesizing study results using meta-analysis. Cochrane Collaboration directives and MOOSE guidelines were followed. We conducted systematic literature searches on each model component in Medline. An inverse variance approach to meta-analysis was used to synthesize study effect sizes and estimate between-studies variance ('heterogeneity'). Meta-regression models were conducted to explain the heterogeneity using several effect modifiers, including the sample age and sex ratio. Among 3,183 initially identified abstracts, after screening by two independent raters (95-98% agreement), 29 high-quality studies were included in the meta-analysis. The following trends were observed: Shift type. Compared to morning shifts, injury risk significantly increased on night shifts (RR = 1.36 [95%CI = 1.15-1.60], n = 14 studies), while risk was slightly elevated on afternoon/evening shifts, although non-significantly (RR = 1.12 [0.76-1.64], n = 9 studies). Meta-regressions revealed worker's age as a significant effect modifier: adolescent workers (≤ 20 y) showed a decreased risk on the afternoon/evening shift compared to both morning shifts and adult workers (p < 0.05). Number of consecutive shifts. Compared to the first shift in a block of consecutive shifts, risk increased exponentially for morning shifts (e.g., 4th: RR = 1.09 [0.90-1.32]; n = 6 studies) and night shifts (e.g., 4th: RR = 1.36 [1.14-1.62]; n = 8 studies), while risk on afternoon/evening shifts appeared unsystematic. Shift length. Injury risk rose substantially beyond the 9th hour on duty, a trend that was mirrored when looking at shift lengths (e.g., >12 h: RR = 1.34 [1.04-1.51], n = 3 studies). Rest breaks. Risk decreased for any rest break duration (e.g., 31-60 min: RR = 0.35 [0.29-0.43], n = 2 studies). With regards to time between breaks, risk increased with every additional half hour spent on the work task compared to the first 30 min (e.g., 90-119 min: RR = 1.62 [1.00-2.62], n = 3 studies). Rest break duration and interval seem to interact such that with increasing duration, the time between breaks becomes irrelevant. The updated "Risk Index". All four components were combined to form the updated model and the relative risk values estimated for a variety of work schedules. The resulting "Risk Map" shows regions of highest risk when rest breaks are not taken frequently enough (i.e. <4 h) or are too short (i.e. <30 min), when shift length exceeds 11 h, and when work takes place during the night (particularly for >3 consecutive night shifts). The "Risk Index" is proposed as an empirical model to predict occupational 'accident' and injury risk based on the most recent data in the field, and can serve as a tool to evaluate hazards and maximize safety across different work schedules.

Penguin Proxies: Deciphering Millennial-Scale Antarctic Ecosystem Change using Amino Acid Stable Isotope Analysis.

NASA Astrophysics Data System (ADS)

Michelson, C.; McMahon, K.; Emslie, S. D.; Patterson, W. P.; McCarthy, M. D.; Polito, M. J.

2017-12-01

The Southern Ocean ecosystem is undergoing rapid environmental change due to ongoing and historic anthropogenic impacts such as climate change and marine mammal harvesting. These disturbances may have cascading effects through the Antarctic food webs, resulting in profound shifts in the sources and cycling of organic matter supporting higher-trophic organisms, such as penguins. For example, bulk stable isotope analyses of modern and ancient preserved penguin tissues suggest variations in penguin feeding ecology throughout the Holocene with dramatic isotopic shifts in the last 200 years. However, it is not clear whether these isotopic shifts resulted from changes at the base of the food web, dietary shifts in penguins, or some combination of both factors. Newly developed compound-specific stable nitrogen isotope analysis of individual amino acids (CSIA-AA) may provide a powerful new tool to tease apart these confounding variables. Stable nitrogen isotope values of trophic amino acids (e.g., glutamic acid) increase substantially with each trophic transfer in the food web, while source amino acid (e.g., phenylalanine) stable nitrogen isotope values remain relatively unchanged and reflect ecosystem baselines. As such, we can use this CSIA-AA approach to decipher between baseline and dietary shifts in penguins over time from modern and ancient eggshells of Pygoscelis penguins in the Antarctic Peninsula and the Ross Sea regions of Antarctica. In order to accurately apply this CSIA-AA approach, we first characterized the trophic fractionation factors of individual amino acids between diet and penguin consumers in a long-term controlled penguin feeding experiment. We then applied these values to modern and ancient eggshells from the Antarctic Peninsula and Ross Sea to evaluate shifts in penguin trophic dynamics as a function of climate and anthropogenic interaction throughout much of the Holocene. This work develops a cutting edge new molecular geochemistry approach applied to penguins as sensitive indicators of past environmental change in Antarctica.

Viscoelastic effect on acoustic band gaps in polymer-fluid composites

NASA Astrophysics Data System (ADS)

Merheb, B.; Deymier, P. A.; Muralidharan, K.; Bucay, J.; Jain, M.; Aloshyna-Lesuffleur, M.; Greger, R. W.; Mohanty, S.; Berker, A.

2009-10-01

In this paper, we present a theoretical analysis of the propagation of acoustic waves through elastic and viscoelastic two-dimensional phononic crystal structures. Numerical calculations of transmission spectra are conducted by extending the finite-difference-time-domain method to account for linear viscoelastic materials with time-dependent moduli. We study a phononic crystal constituted of a square array of cylindrical air inclusions in a solid viscoelastic matrix. The elastic properties of the solid are those of a silicone rubber. This system exhibits very wide band gaps in its transmission spectrum that extend to frequencies in the audible range of the spectrum. These gaps are characteristic of fluid matrix/air inclusion systems and result from the very large contrast between the longitudinal and transverse speeds of sound in rubber. By treating the matrix as a viscoelastic medium within the standard linear solid (SLS) model, we demonstrate that viscoelasticity impacts the transmission properties of the rubber/air phononic crystal not only by attenuating the transmitted acoustic waves but also by shifting the passing bands frequencies toward lower values. The ranges of frequencies exhibiting attenuation or frequency shift are determined by the value of the relaxation time in the SLS model. We show that viscoelasticity can be used to decrease the frequency of pass bands (and consequently stop bands) in viscoelastic/air phononic crystals.

Effects of chlorogenic acid on voltage-gated potassium channels of trigeminal ganglion neurons in an inflammatory environment.

PubMed

Liu, Fei; Lu, Xiao-Wen; Zhang, Yu-Jiao; Kou, Liang; Song, Ning; Wu, Min-Ke; Wang, Min; Wang, Hang; Shen, Jie-Fei

2016-10-01

Chlorogenic acid (CGA) composed of coffee acid and quinic acid is an effective ingredient of many foods and medicines and widely exhibits biological effects. Recently, it is reported to have analgesic effect. However, little is known about the analgesic mechanism of CGA. In this study, whole-cell patch-clamp recordings were performed on two main subtypes (I K,A and I K,V channels) of voltage-gated potassium (K V ) channels in small-diameter(<30μm) trigemianl ganglion neurons to analyze the effects of CGA in an inflammatory environment created by Prostaglandin E 2 (PGE 2 ). On one hand, the activation and inactivation V 1/2 values of I K,A and I K,V channels showed an elevation towards a depolarizing shift caused by PGE 2 . On the other hand, the activation and inactivation V 1/2 values of the two channels had a reduction towards a hyperpolarizing shift caused by CGA under PGE 2 pretreatment. Our results demonstrated that CGA may exhibited an analgesic effect by promoting K V channels activation and inactivation under inflammatory condition, which provided a novel molecular and ionic mechanism underlying anti-inflammatory pain of CGA. Copyright © 2016 Elsevier Inc. All rights reserved.

Individual Differences in Response to Sleep Deprivation: Assessment of Fatigue Following Sleep Loss

NASA Technical Reports Server (NTRS)

Carskadon, Mary A.

1997-01-01

Previous work has indicated that a small but significant number of participants in sleep deprivation studies or in simulated shift work experiments manifests an exaggerated performance decrement when they reach a critical point in the experiment, usually near the trough of the circadian cycle or the middle of the night. Those who show this exaggerated response do not appear to differ from other non-nal volunteers in any substantial way according to usual screening criteria or baseline values. The present study aims to examine factors that may provide the basis for this extreme response. We propose that a preexisting sleep deficit-as manifested by low values on the Multiple Sleep Latency Test (MSLT)-may account for extreme responders. It has been shown that among normal volunteers screened for a variety of studies, approximately 20 to 25 percent show low (< 6 minutes) MSLT scores on a consistent basis, whereas a like proportion shows consistently high MSLT scores (> 13 minutes). Additionally, studies by this group have indicated that subjects with low MSLT scores may suffer from chronic insufficient sleep, as further substantiated by the finding that they have consistently higher nocturnal sleep efficiency and that their MSLT scores rise to normal values when sleep is extended. We hypothesize that the short MSLT subjects have a significant long-term sleep deficit that leads to a marked intolerance for sleep deprivation or shift work. We further suggest that this sleep debt may signify an increased sleep need in these individuals that is not met either due to personal preference or to societal pressures (or both). If this speculation is accurate, then we predict that the tolerance for sleep deprivation in such individuals can be increased by "pretreatment" with sleep extension. Thus, the present study is designed to test the following two hypotheses: (1) subjects with nominal sleep patterns who have low MSLT scores (e.g., Sleepy subjects) will show an exaggerated response (performance decrement) to sleep loss compared to subjects who have high MSLT scores (Alert subjects) on a nominal sleep schedule; (2) when permitted to extend sleep--thus discharging their sleep debt-the Sleepy subjects will show a sleep-loss response resembling that of the Alert subjects.

Individual Differences in Response to Sleep Deprivation: Assessment of Fatigue Following Sleep Loss

NASA Technical Reports Server (NTRS)

Carskadon, Mary A.

1997-01-01

Previous work has indicated that a small but significant number of participants in sleep deprivation studies or in simulated shift work experiments manifests an exaggerated performance decrement when they reach a critical point in the experiment, usually near the trough of the circadian cycle or the middle of the night. Those who show this exaggerated response do not appear to differ from other non-nal volunteers in any substantial way according to usual screening criteria or baseline values. The present study aims to examine factors that may provide the basis for this extreme response. We propose that a preexisting sleep deficit-as manifested by low values on the Multiple Sleep Latency Test (MSLT)-may account for extreme responders. Roth and colleagues (1993) have shown that among normal volunteers screened for a variety of studies, approximately 20 to 25 percent show low (< 6 minutes) MSLT scores on a consistent basis, whereas a like proportion shows consistently high MSLT scores (> 13 minutes). Additionally, studies by this group have indicated that subjects with low MSLT scores may suffer from chronic insufficient sleep (Roth et al., 1993), as further substantiated by the finding that they have consistently higher nocturnal sleep efficiency and that their MSLT scores rise to normal values when sleep is extended (Roehrs et al., 1996). We hypothesize that the short MSLT subjects have a significant long-term sleep deficit that leads to a marked intolerance for sleep deprivation or shift work. We further suggest that this sleep debt may signify an increased sleep need in these individuals that is not met either due to personal preference or to societal pressures (or both). If this speculation is accurate, then we predict that the tolerance for sleep deprivation in such individuals can be increased by "pretreatment" with sleep extension. Thus, the present study is designed to test the following two hypotheses: subjects with nominal sleep patterns who have low MSLT scores (e.g., Sleepy subjects) will show an exaggerated response (performance decrement) to sleep loss compared to subjects who have high MSLT scores (Alert subjects) on a nominal sleep schedule. when permitted to extend sleep-thus discharging their sleep debt-the Sleepy subjects will show a sleep-loss response resembling that of the Alert subjects.

Individual Differences in Response to Sleep Deprivation: Assessment of Fatigue Following Sleep Loss

NASA Technical Reports Server (NTRS)

Carskadon, Mary A.

1997-01-01

Previous work has indicated that a small but significant number of participants in sleep deprivation studies or in simulated shift work experiments manifests an exaggerated performance decrement when they reach a critical point in the experiment, usually near the trough of the circadian cycle or the middle of the night. Those who show this exaggerated response do not appear to differ from other normal volunteers in any substantial way according to usual screening criteria or baseline values. The present study aims to examine factors that may provide the basis for this extreme response. We propose that a preexisting sleep deficit-as manifested by low values on the Multiple Sleep Latency Test (MSLT)-may account for extreme responders. Roth and colleagues (1993) have shown that among normal volunteers screened for a variety of studies, approximately 20 to 25 percent show low (< or = 6 minutes) MSLT scores on a consistent basis, whereas a like proportion shows consistently high MSLT scores (> or = 13 minutes). Additionally, studies by this group have indicated that subjects with low MSLT scores may suffer from chronic insufficient sleep (Roth et al., 1993), as further substantiated by the finding that they have consistently higher nocturnal sleep efficiency and that their MSLT scores rise to normal values when sleep is extended (Roehrs et al., 1996). We hypothesize that the short MSLT subjects have a significant long-term sleep deficit that leads to a marked intolerance for sleep deprivation or shift work. We further suggest that this sleep debt may signify an increased sleep need in these individuals that is not met either due to personal preference or to societal pressures (or both). If this speculation is accurate, then we predict that the tolerance for sleep deprivation in such individuals can be increased by "pretreatment" with sleep extension. Thus, the present study is designed to test the following two hypotheses: subjects with nominal sleep patterns who have low MSLT scores (e.g., Sleepy subjects) will show an exaggerated response (performance decrement) to sleep loss compared to subjects who have high MSLT scores (Alert subjects) on a nominal sleep schedule. When permitted to extend sleep-thus discharging their sleep debt-the Sleepy subjects will show a sleep-loss response resembling that of the Alert subjects.

Dimmable sunlight-like organic light emitting diodes with ultra-high color rendering index

NASA Astrophysics Data System (ADS)

Wu, Jin-Han; Chi, Chien-An; Chiang, Chang-Lin; Chen, Guan-Yu; Lin, Yi-Ping; Chen, Cheng-Chang; Ho, Shu-Yi; Chen, Shih-Pu; Li, Jung-Yu

2016-05-01

We propose novel dimmable sunlight-like white organic light-emitting diodes that were fabricated using three luminophores to form an emitting spectrum similar to black body radiation at 2250 K with ultra-high color rendering index (CRI) value of 91, which nearly remained the constant at various luminance values ranging from 100 to more than 2500 cd/m2 at Commission Internationale de l'Eclairage chromaticity coordinates of (0.51, 0.41). Introducing charge modification layers suppressed the energy transfer between the emitting material layers and increased the probability of carrier recombination. Moreover, we reveal that covering long-wavelength ranges played a vital role in achieving high CRI values; the CRI values of a spectrum artificially shifted toward a long-wavelength direction (from 610 to 620 nm) remained constant, whereas those of a spectrum shifted toward a short-wavelength direction (from 610 to 600 nm) dropped to 79.

Properties of nanocomposite PP fibres

NASA Astrophysics Data System (ADS)

Smole, Majda S.; Stakne, Kristina; Svetec, Diana G.; Kleinschek, Karin S.; Ribitsch, Volker

2005-06-01

PP-based nanocomposite fibres were prepared by direct polymer melt intercalation. With the intention to determine the size and dispersion of nanoparticles in the polymer matrix, fibres were plasma etched and SEM observations were performed. The influence of nanofiller content and coupling agent on electrokinetic properties was studied. PP monofilament fibres exhibit hydrophobe character with negative zeta potential value. The zeta potential value of co-polymer PP fibre decreases with increasing PPAA content and the isoelectric point IEP of co-polymer samples shifts towards acid region. Addition of modified montmorillonite due to the particles electropositive character, affects the reduction of zeta potential value and a slight shift of IEP towards neutral region is observed. Nano-particles content influences electrokinetic fibres properties, i.e. ZP value is changed, however IE point is not significantly changed by different concentrations of nanofiller. In addition to, mechanical properties of nanocomposite fibres were determined.

Contributions of climate change to the boundary shifts in the farming-pastoral ecotone in northern China since 1970

NASA Astrophysics Data System (ADS)

Shi, W.; Liu, Y.; Shi, X.

2017-12-01

Critical transitions of farming-pastoral ecotone (FPE) boundaries can be affected by climate change and human activities, yet current studies have not adequately analyzed the spatially explicit contributions of climate change to FPE boundary shifts, particularly those in different regions and periods. In this study, we present a series of analyses at the point (gravity center analysis), line (boundary shifts detected using two methods) and area (spatial analysis) levels to quantify climate contributions at the 1 km scale in each ecological functional region during three study periods from the 1970s to the 2000s using climate and land use data. Both gravity center analysis and boundary shift detection reveal similar spatial patterns, with more extensive boundary shifts in the northeastern and southeastern parts of the FPE in northern China, especially during the 1970s-1980s and 1990s-2000s. Climate contributions in the X- and Y-coordinate directions and in the directions of transects along boundaries show that significant differences in climate contributions to FPE boundary shifts exist in different ecological regions during the three periods. Additionally, the results in different directions exhibit good agreement in most of the ecological functional regions during most of the periods. However, the contribution values in the directions of transects along the boundaries (with 1-17%) were always smaller than those in the X-and Y-coordinate directions (4-56%), which suggests that the analysis in the transect directions is more stable and reasonable. Thus, this approach provides an alternative method for detecting the climate contributions to boundary shifts associated with land use changes. Spatial analysis of the relationship between climate change and land use change in the context of FPE boundary shifts in northern China provides further evidence and explanation of the driving forces of climate change. Our findings suggest that an improved understanding of the quantitative contributions of climate change to the formation and transition of the FPE in northern China is essential for addressing current and future adaptation and mitigation measures and regional land use management.

Mechanisms of Choice Behavior Shift Using Cue-approach Training.

PubMed

Bakkour, Akram; Leuker, Christina; Hover, Ashleigh M; Giles, Nathan; Poldrack, Russell A; Schonberg, Tom

2016-01-01

Cue-approach training has been shown to effectively shift choices for snack food items by associating a cued button-press motor response to particular food items. Furthermore, attention was biased toward previously cued items, even when the cued item is not chosen for real consumption during a choice phase. However, the exact mechanism by which preferences shift during cue-approach training is not entirely clear. In three experiments, we shed light on the possible underlying mechanisms at play during this novel paradigm: (1) Uncued, wholly predictable motor responses paired with particular food items were not sufficient to elicit a preference shift; (2) Cueing motor responses early - concurrently with food item onset - and thus eliminating the need for heightened top-down attention to the food stimulus in preparation for a motor response also eliminated the shift in food preferences. This finding reinforces our hypothesis that heightened attention at behaviorally relevant points in time is key to changing choice behavior in the cue-approach task; (3) Crucially, indicating choice using eye movements rather than manual button presses preserves the effect, thus demonstrating that the shift in preferences is not governed by a learned motor response but more likely via modulation of subjective value in higher associative regions, consistent with previous neuroimaging results. Cue-approach training drives attention at behaviorally relevant points in time to modulate the subjective value of individual items, providing a mechanism for behavior change that does not rely on external reinforcement and that holds great promise for developing real world behavioral interventions.

A Late Holocene environmental history of a bat guano deposit from Romania: an isotopic, pollen and microcharcoal study

NASA Astrophysics Data System (ADS)

Forray, Ferenc L.; Onac, Bogdan P.; Tanţău, Ioan; Wynn, Jonathan G.; Tămaş, Tudor; Coroiu, Ioan; Giurgiu, Alexandra M.

2015-11-01

A 1.5-m-long core from a bat guano deposit in Zidită Cave (western Romania) has provided a 900-year record of environmental change. Shifts in δ13C values of bulk guano (between -22.6 and -27.5‰) combined with guano-sourced pollen and microcharcoal information show significant changes in the structure of vegetation and plant biomass. Cave guano δ13C values reflect the dietary preferences of bats which are controlled by local vegetation dynamics, which in turn depend on local climatic conditions. Neither δ13C values nor pollen association in guano changed strikingly over the Medieval Warm Period (MWP) and Little Ice Age (LIA) transition. Instead, an overall decreasing trend of δ13C values between ca. AD 1200 and 1870-1900 defines the duration of LIA. A shift toward cooler and wetter conditions at ca. AD 1500 noticed in the pollen record by an increase in Fagus sylvatica and Alnus and the decrease of Carpinus betulus, may indicate the first major change at the beginning of the LIA. Evidence for two major cold spells occurring around AD 1500 and ca. AD 1870 comes from both δ13C and pollen record. In between these events, the cave region experienced a warmer and drier climate but colder and wetter than the MWP, favouring the expansion of Quercus, Fraxinus and Tilia simultaneously with the decrease of F. sylvatica and Poaceae. Human impact in the studied area is mainly related to agriculture, grazing and deforestation. The effects are most pronounced after AD 1845 when the pollen of cereals increases and Zea is recorded (AD 1845). Higher percentages of microcharcoal particles in the guano sequence are generally correlated with agricultural activities like land cleaning via controlled fires.

Transcranial color-coded duplex sonography for evaluation of midline-shift after chronic-subdural hematoma evacuation (TEMASE): A prospective study.

PubMed

Cattalani, Andrea; Grasso, Vincenzo Maria; Vitali, Matteo; Gallesio, Ivan; Magrassi, Lorenzo; Barbanera, Andrea

2017-11-01

The incidence of chronic Subdural hematoma (cSDH) is increasing and its rate of recurrence varies from 5 to 33%. A postoperative brain midline-shift (MLS) on computed tomography (CT) equal or larger than 5mm is a risk factor for recurrence. Transcranial color-coded duplex sonography (TCCDS) is a noninvasive bedside reproducible technique useful to detect MLS. The aim of our study was to compare in patients affected by cSDH, the values of MLS obtained pre- and post-operatively by TCCDS and brain CT. 32 patients affected by cSDH entered the study between July 2016 and January 2017. MLS values obtained by TCCDS and brain CT were compared using Bland-Altman plot and linear regression analysis. Using the same techniques we also explored if the agreement between the two imaging modes was comparable in pre- and post-operative data pairs. 64 data pairs of MLS values obtained by TCCDS and CT were analysed. Bland-Altman diagrams did not show any systematic bias of the data and linear regression indicated a significant correlation between the two measures both before and after hematoma evacuation. In patients affected by cSDH, MLS values obtained before and after surgery by TCCDS are comparable to those obtained by CT; TCCDS might be considered an alternative to CT scan in the management of patients after cSDH evacuation. We suggest that close clinical bedside examination and TCCDS might be appropriate for the post-operative management of cSDH, reserving CT scan only to patients with overt clinical deterioration and/or increasing MLS. Copyright © 2017 Elsevier B.V. All rights reserved.

Preventing Fusion Mass Shift Avoids Postoperative Distal Curve Adding-on in Adolescent Idiopathic Scoliosis.

PubMed

Shigematsu, Hideki; Cheung, Jason Pui Yin; Bruzzone, Mauro; Matsumori, Hiroaki; Mak, Kin-Cheung; Samartzis, Dino; Luk, Keith Dip Kei

2017-05-01

Surgery for adolescent idiopathic scoliosis (AIS) is only complete after achieving fusion to maintain the correction obtained intraoperatively. The instrumented or fused segments can be referred to as the "fusion mass". In patients with AIS, the ideal fusion mass strategy has been established based on fulcrum-bending radiographs for main thoracic curves. Ideally, the fusion mass should achieve parallel endplates of the upper and lower instrumented vertebra and correct any "shift" for truncal balance. Distal adding-on is an important element to consider in AIS surgery. This phenomenon represents a progressive increase in the number of vertebrae included distally in the primary curvature and it should be avoided as it is associated with unsatisfactory cosmesis and an increased risk of revision surgery. However, it remains unknown whether any fusion mass shift, or shift in the fusion mass or instrumented segments, affects global spinal balance and distal adding-on after curve correction surgery in patients with AIS. (1) To investigate the relationship among postoperative fusion mass shift, global balance, and distal adding-on phenomenon in patients with AIS; and (2) to identify a cutoff value of fusion mass shift that will lead to distal adding-on. This was a retrospective study of patients with AIS from a single institution. Between 2006 and 2011 we performed 69 selective thoracic fusions for patients with main thoracic AIS. All patients were evaluated preoperatively and at 2 years postoperatively. The Cobb angle between the cranial and caudal endplates of the fusion mass and the coronal shift between them, which was defined as "fusion mass shift", were measured. Patients with a fusion mass Cobb angle greater than 20° were excluded to specifically determine the effect of fusion mass shift on distal adding-on phenomenon. Fusion mass shift was empirically set as 20 mm for analysis. Therefore, of the 69 patients who underwent selective thoracic fusion, only 52 with a fusion mass Cobb angle of 20° or less were recruited for study. We defined patients with a fusion mass shift of 20 mm or less as the balanced group and those with a fusion mass shift greater than 20 mm as the unbalanced group. A receiver operating characteristic (ROC) curve was used to determine the cutoff point of fusion mass shift for adding-on. Of the 52 patients studied, fusion mass shift (> 20 mm) was noted in 11 (21%), and six of those patients had distal adding-on at final followup. Although global spinal balance did not differ significantly between patients with or without fusion mass shift, the occurrence of adding-on phenomenon was significantly higher in the unbalanced group (55% (six of 11 patients), odds ratio [OR], 8.6; 95% CI, 2-39; p < 0.002) than the balanced group (12% [five of 41 patients]). Based on the ROC curve analysis, a fusion mass shift more than 18 mm was observed as the cutoff point for distal adding-on phenomenon (area under the curve, 0.70; 95% CI, 0.5-0.9; likelihood ratio, 5.0; sensitivity, 0.64; specificity, 0.73; positive predictive value, 39% [seven of 18 patients]; negative predictive value, 88% [30 of 34 patients]; OR, 4.8; 95% CI, 1-20; p = 0.02). Our study illustrates the substantial utility of the fulcrum-bending radiograph in determining fusion levels that can avoid fusion mass shift; thereby, underlining its importance in designing personalized surgical strategies for patients with scoliosis. Preoperatively, determining fusion levels by fulcrum-bending radiographs to avoid residual fusion mass shift is imperative. Intraoperatively, any fusion mass shift should be corrected to avoid distal adding-on, reoperation, and elevated healthcare costs. Level II, prognostic study.

Skew information in the XY model with staggered Dzyaloshinskii-Moriya interaction

NASA Astrophysics Data System (ADS)

Qiu, Liang; Quan, Dongxiao; Pan, Fei; Liu, Zhi

2017-06-01

We study the performance of the lower bound of skew information in the vicinity of transition point for the anisotropic spin-1/2 XY chain with staggered Dzyaloshinskii-Moriya interaction by use of quantum renormalization-group method. For a fixed value of the Dzyaloshinskii-Moriya interaction, there are two saturated values for the lower bound of skew information corresponding to the spin-fluid and Néel phases, respectively. The scaling exponent of the lower bound of skew information closely relates to the correlation length of the model and the Dzyaloshinskii-Moriya interaction shifts the factorization point. Our results show that the lower bound of skew information can be a good candidate to detect the critical point of XY spin chain with staggered Dzyaloshinskii-Moriya interaction.

Silver Coating for High-Mass-Accuracy Imaging Mass Spectrometry of Fingerprints on Nanostructured Silicon.

PubMed

Guinan, Taryn M; Gustafsson, Ove J R; McPhee, Gordon; Kobus, Hilton; Voelcker, Nicolas H

2015-11-17

Nanostructure imaging mass spectrometry (NIMS) using porous silicon (pSi) is a key technique for molecular imaging of exogenous and endogenous low molecular weight compounds from fingerprints. However, high-mass-accuracy NIMS can be difficult to achieve as time-of-flight (ToF) mass analyzers, which dominate the field, cannot sufficiently compensate for shifts in measured m/z values. Here, we show internal recalibration using a thin layer of silver (Ag) sputter-coated onto functionalized pSi substrates. NIMS peaks for several previously reported fingerprint components were selected and mass accuracy was compared to theoretical values. Mass accuracy was improved by more than an order of magnitude in several cases. This straightforward method should form part of the standard guidelines for NIMS studies for spatial characterization of small molecules.

Equal vibrotactile sense thresholds of the fingers and its diagnostic significance for hand-arm vibration syndrome.

PubMed

Cheng, H; Zhang, X C; Duan, L; Ma, Y; Wang, J X

1995-01-01

The vibrotactile sense thresholds (VSTs) of the middle fingers of 60 healthy persons and 97 patients with Hand-Arm Vibration Syndrome (HAVS) or subclinical HAVS were measured quantitatively. Intermittent vibratory irritations were adopted, with vibration stimulus frequencies at 8, 16, 31.5, 63, 125, 250, and 500 Hz. The equal VST contours of the fingers were mapped. Results showed that the VSTs of the normal group were not correlated with sex or handedness. From 8 Hz to 250 Hz the equal VST contours of the normal group were relatively flat; at more than 250 Hz the contours began an abrupt ascent. The VST values had a logarithmic rising tendency with the increasing age of subjects. In the equal VST contours the frequency of the most sensitive threshold value was 125 Hz in the normal group and 8 Hz in the HAVS group. The patients' VST values were higher than that of the healthy persons. The vibrotactilegram showed that the VST values of the patient groups first shifted at high frequencies and VST loss displayed a "V"-type hollow at 125 Hz and 250 Hz. The quantitative test method of VST was a valuable auxiliary detection method for HAVS. The "V"-type hollow of VST was an early clinical manifestation of HAVS.

Late Pleistocene Southeast Amazonia Paleoenvironmental reconstruction inferred by bulk, isotopic and molecular organic matter. Saci lake-Para-Brazil

NASA Astrophysics Data System (ADS)

Martins, G. S.; Cordeiro, R. C.; Turcq, B.; Moreira, L. S.; Bouloubassi, I.; Sifeddine, A.

2014-12-01

Bulk, Isotope and biolomecular analysis supported by 22 14C AMS dates, allowed the reconstruction of environmental changes during the last 35 000 years BP in the Southeast Amazonian basin. A terrestrial origin has been inferred for the odd carbon-numbered long-chain (>C27) n-alkanes. The entire n-alkane δ13C range between -31.7‰ and -36.8‰, which is the isotopic range occupied by C3 vegetation. The C29:C31 ratio shows that a gramineae contribution is higher during the Pleistocene than in Holocene. The n-alkanes concentration decrease between 32 000 - 18 000, suggesting a increase in arid conditions. The ACL index confirm this interpretation showing high values due the Pleistocene linked to more hydrological stress. A shift in the abundance of n-alkane and isotopic values are observed across the late Pleistocene glacial-Holocene interglacial climate change, suggesting a climate-induced vegetational change. During the middle Holocene the n-alcanes values decreases indicating rain forest regression accompanied by increase in the ACL values confirming the dry climate conditions. Comparison with other South American records, our record indicates regression/expansion of the rain forest linked to the South American System monsoon activity since 35 kyrs.

Illumina sequencing-based analyses of bacterial communities during short-chain fatty-acid production from food waste and sewage sludge fermentation at different pH values.

PubMed

Cheng, Weixiao; Chen, Hong; Yan, ShuHai; Su, Jianqiang

2014-09-01

Short-chain fatty acids (SCFAs) can be produced by primary and waste activated sludge anaerobic fermentation. The yield and product spectrum distribution of SCFAs can be significantly affected by different initial pH values. However, most studies have focused on the physical and chemical aspects of SCFA production by waste activated sludge fermentation at different pH values. Information on the bacterial community structures during acidogenic fermentation is limited. In this study, comparisons of the bacterial communities during the co-substrate fermentation of food wastes and sewage sludge at different pH values were performed using the barcoded Illumina paired-end sequencing method. The results showed that different pH environments harbored a characteristic bacterial community, including sequences related to Lactobacillus, Prevotella, Mitsuokella, Treponema, Clostridium, and Ureibacillus. The most abundant bacterial operational taxonomic units in the different pH environments were those related to carbohydrate-degrading bacteria, which are associated with constituents of co-substrate fermentation. Further analyses showed that during organic matter fermentation, a core microbiota composed of Firmicutes, Proteobacteria, and Bacteroidetes existed. Comparison analyses revealed that the bacterial community during fermentation was significantly affected by the pH, and that the diverse product distribution was related to the shift in bacterial communities.

Fin whales as bioindicators of multi-decadal change in carbon and oxygen stable isotope shifts in the North Atlantic.

PubMed

Borrell, A; Saiz, L; Víkingsson, G A; Gaufier, P; López Fernández, A; Aguilar, A

2018-07-01

Global changes, and particularly the massive release of CO 2 to the atmosphere and subsequent global warming, have altered the baselines of carbon and oxygen stable isotopic ratios. Temporal shifts in these baselines can be advantageously monitored through cetacean skin samples because these animals are highly mobile and therefore integrate in their tissues the heterogeneity of local environmental signals. In this study, we examine variation of δ 13 C and δ 18 O values in the skin of fin whales sampled over three decades in two different North Atlantic feeding grounds: west Iceland and northwest Spain. These locations are situated about 2700 km apart and thus represent a wide latitudinal range within the North Atlantic Ocean. The δ 13 C decrease in both areas is attributed to the burning of fossil fuels and increased deforestation worldwide, the so-called Suess effect. The dissimilarity in the magnitude of the shift between the two areas is coincidental with previous information on local shifts and lies within the ranges of variation observed. δ 18 O values experienced a minimal, yet significant change in fin whales from W Iceland (a decline of -0.44‰ between 1986 and 2013) but not in those from NW Spain. This is in concordance with a higher rise in temperatures in the former area than in the latter. The study validates the use of cetacean skin to monitor temporal and geographical shifts in stable isotopic values and alerts that, when applying this tool to ecological research, comparisons between sample sets should take into account temporal and latitudinal scales. Copyright © 2018 Elsevier Ltd. All rights reserved.

Cross-shift changes in FEV1 in relation to wood dust exposure: the implications of different exposure assessment methods

PubMed Central

Schlunssen, V; Sigsgaard, T; Schaumburg, I; Kromhout, H

2004-01-01

Background: Exposure-response analyses in occupational studies rely on the ability to distinguish workers with regard to exposures of interest. Aims: To evaluate different estimates of current average exposure in an exposure-response analysis on dust exposure and cross-shift decline in FEV1 among woodworkers. Methods: Personal dust samples (n = 2181) as well as data on lung function parameters were available for 1560 woodworkers from 54 furniture industries. The exposure to wood dust for each worker was calculated in eight different ways using individual measurements, group based exposure estimates, a weighted estimate of individual and group based exposure estimates, and predicted values from mixed models. Exposure-response relations on cross-shift changes in FEV1 and exposure estimates were explored. Results: A positive exposure-response relation between average dust exposure and cross-shift FEV1 was shown for non-smokers only and appeared to be most pronounced among pine workers. In general, the highest slope and standard error (SE) was revealed for grouping by a combination of task and factory size, the lowest slope and SE was revealed for estimates based on individual measurements, with the weighted estimate and the predicted values in between. Grouping by quintiles of average exposure for task and factory combinations revealed low slopes and high SE, despite a high contrast. Conclusion: For non-smokers, average dust exposure and cross-shift FEV1 were associated in an exposure dependent manner, especially among pine workers. This study confirms the consequences of using different exposure assessment strategies studying exposure-response relations. It is possible to optimise exposure assessment combining information from individual and group based exposure estimates, for instance by applying predicted values from mixed effects models. PMID:15377768

Predicting the pKa and stability of organic acids and bases at an oil-water interface.

PubMed

Andersson, M P; Olsson, M H M; Stipp, S L S

2014-06-10

We have used density functional theory and the implicit solvent model, COSMO-RS, to investigate how the acidity constant, pKa, of organic acids and bases adsorbed at the organic compound-aqueous solution interface changes, compared to its value in the aqueous phase. The pKa determine the surface charge density of the molecules that accumulate at the fluid-fluid interface. We have estimated the pKa by comparing the stability of the protonated and unprotonated forms of a series of molecules in the bulk aqueous solution and at an interface where parts of each molecule reside in the hydrophobic phase and the rest remains in the hydrophilic phase. We found that the pKa for acids is shifted by ∼1 pH unit to higher values compared to the bulk water pKa, whereas they are shifted to lower values by a similar amount for bases. Because this pKa shift is similar in magnitude for each of the molecules studied, we propose that the pKa for molecules at a water-organic compound interface can easily be predicted by adding a small shift to the aqueous pKa. This shift is general and correlates with the functional group. We also found that the relative composition of molecules at the fluid-fluid interface is not the same as in the bulk. For example, species such as carboxylic acids are enriched at the interface, where they can dominate surface properties, even when they are a modest component in the bulk fluid. For high surface concentrations of carboxylic acid groups at an interface, such as a self-assembled monolayer, we have demonstrated that the pKa depends on the degree of deprotonation through direct hydrogen bonding between protonated and deprotonated acidic headgroups.

Femtosecond-pulse inscription of fiber Bragg gratings with single or multiple phase-shifts in the structure

NASA Astrophysics Data System (ADS)

Wolf, Alexey; Dostovalov, Alexandr; Skvortsov, Mikhail; Raspopin, Kirill; Parygin, Alexandr; Babin, Sergey

2018-05-01

In this work, long high-quality fiber Bragg gratings with phase shifts in the structure are inscribed directly in the optical fiber by point-by-point technique using femtosecond laser pulses. Phase shifts are introduced during the inscription process with a piezoelectric actuator, which rapidly shifts the fiber along the direction of its movement in a chosen point of the grating with a chosen shift value. As examples, single and double π phase shifts are introduced in fiber Bragg gratings with a length up to 34 mm in passive fibers, which provide corresponding transmission peaks with bandwidth less than 1 pm. It is shown that 37 mm π -phase-shifted grating inscribed in an active Er-doped fiber forms high-quality DFB laser cavity generating single-frequency radiation at 1550 nm with bandwidth of 20 kHz and signal-to-noise ratio of >70 dB. The inscription technique has a high degree of performance and flexibility and can be easily implemented in fibers of various types.

Quantum size effect in the photoluminescence properties of p-type semiconducting transparent CuAlO2 nanoparticles

NASA Astrophysics Data System (ADS)

Narayan Banerjee, Arghya; Woo Joo, Sang; Min, Bong-Ki

2012-12-01

Photoluminescence properties of CuAlO2 nanoparticles, deposited by a cost-effective direct current sputtering technique, have been studied. The nanoparticles show room-temperature photoluminescence peaks of near-band-edge emission due to recombination of free excitons. A blue-shift in the emission peaks as a decreasing function of the nanoparticle sizes is observed, which is attributed to the quantum confinement effect within the CuAlO2 nanoparticles. Theoretical calculations of bandgap enhancement values are found to be matching fairly well with that of the experimentally obtained values, confirming the existence of the quantum size effect within the nanomaterial. Approximate calculations show that the confinement effect falls within moderate-to-weak confinement regime. X-ray diffraction and electron microscopic measurements confirm the proper phase formation and nanocrystalline structure of the as-deposited nanoparticles. The room-temperature and size-dependent photoluminescence properties of this nanomaterial will be very useful for light emitting diode and similar optoelectronic applications.