Early MRI changes in glioblastoma in the period between surgery and adjuvant therapy.

PubMed

Farace, Paolo; Amelio, Dante; Ricciardi, Giuseppe K; Zoccatelli, Giada; Magon, Stefano; Pizzini, Francesca; Alessandrini, Franco; Sbarbati, Andrea; Amichetti, Maurizio; Beltramello, Alberto

2013-01-01

To investigate the increase in MRI contrast enhancement (CE) occurring in glioblastoma during the period between surgery and initiation of chemo-radiotherapy, thirty-seven patients with newly diagnosed glioblastoma were analyzed by early post-operative magnetic resonance (EPMR) imaging within three days of surgery and by pre-adjuvant magnetic resonance (PAMR) examination before adjuvant therapy. Areas of new CE were investigated by use of EPMR diffusion-weighted imaging and PAMR perfusion imaging (by arterial spin-labeling). PAMR was acquired, on average, 29.9 days later than EPMR (range 20-37 days). During this period an increased area of CE was observed for 17/37 patients. For 3/17 patients these regions were confined to areas of reduced EPMR diffusion, suggesting postsurgical infarct. For the other 14/17 patients, these areas suggested progression. For 11/17 patients the co-occurrence of hyperperfusion in PAMR perfusion suggested progression. PAMR perfusion and EPMR diffusion did not give consistent results for 3/17 patients for whom small new areas of CE were observed, presumably because of the poor spatial resolution of perfusion imaging. Before initiation of adjuvant therapy, areas of new CE of resected glioblastomas are frequently observed. Most of these suggest tumor progression, according to EPMR diffusion and PAMR perfusion criteria.

Optimal Design for Placements of Tsunami Observing Systems to Accurately Characterize the Inducing Earthquake

NASA Astrophysics Data System (ADS)

Mulia, Iyan E.; Gusman, Aditya Riadi; Satake, Kenji

2017-12-01

Recently, there are numerous tsunami observation networks deployed in several major tsunamigenic regions. However, guidance on where to optimally place the measurement devices is limited. This study presents a methodological approach to select strategic observation locations for the purpose of tsunami source characterizations, particularly in terms of the fault slip distribution. Initially, we identify favorable locations and determine the initial number of observations. These locations are selected based on extrema of empirical orthogonal function (EOF) spatial modes. To further improve the accuracy, we apply an optimization algorithm called a mesh adaptive direct search to remove redundant measurement locations from the EOF-generated points. We test the proposed approach using multiple hypothetical tsunami sources around the Nankai Trough, Japan. The results suggest that the optimized observation points can produce more accurate fault slip estimates with considerably less number of observations compared to the existing tsunami observation networks.

Concatenation of Observed Grasp Phases with Observer’s Distal Movements: A Behavioural and TMS Study

PubMed Central

De Stefani, Elisa; Innocenti, Alessandro; De Marco, Doriana; Gentilucci, Maurizio

2013-01-01

The present study aimed at determining how actions executed by two conspecifics can be coordinated with each other, or more specifically, how the observation of different phases of a reaching-grasping action is temporary related to the execution of a movement of the observer. Participants observed postures of initial finger opening, maximal finger aperture, and final finger closing of grasp after observation of an initial hand posture. Then, they opened or closed their right thumb and index finger (experiments 1, 2 and 3). Response times decreased, whereas acceleration and velocity of actual finger movements increased when observing the two late phases of grasp. In addition, the results ruled out the possibility that this effect was due to salience of the visual stimulus when the hand was close to the target and confirmed an effect of even hand postures in addition to hand apparent motion due to the succession of initial hand posture and grasp phase. In experiments 4 and 5, the observation of grasp phases modulated even foot movements and pronunciation of syllables. Finally, in experiment 6, transcranial magnetic stimulation applied to primary motor cortex 300 ms post-stimulus induced an increase in hand motor evoked potentials of opponens pollicis muscle when observing the two late phases of grasp. These data suggest that the observation of grasp phases induced simulation which was stronger during observation of finger closing. This produced shorter response times, greater acceleration and velocity of the successive movement. In general, our data suggest best concatenation between two movements (one observed and the other executed) when the observed (and simulated) movement was to be accomplished. The mechanism joining the observation of a conspecific’s action with our own movement may be precursor of social functions. It may be at the basis for interactions between conspecifics, and related to communication between individuals. PMID:24278395

Modeling Evolution of the Chandeleur Barrier Islands, Southeastern Louisiana: Initial Exploration of a Possible Threshold Crossing

NASA Astrophysics Data System (ADS)

Moore, L. J.; List, J. H.; Williams, S. J.

2007-12-01

Airborne photographic and lidar observations of the 72 km-long Chandeleur Island arc in southeastern Louisiana since August 2005 indicate that large volumes of sediment were removed from the islands during and following Hurricane Katrina and suggest that a return to pre-storm island configuration may be unlikely. Others have suggested, based on recent field observations, that the southern portion of the Chandeleur Islands may be showing signs of becoming an inner shelf shoal. In contrast to these observations, plentiful sand has been observed in the nearshore farther to the north; based on this finding it has been suggested that at least the northern portion of the Chandeleur Islands may be poised for recovery. Given the range of observations, it is unclear if Hurricane Katrina initiated a threshold crossing in the Chandeleurs causing the subaerial, landward- migrating barrier islands to begin evolving as submerged sand shoals. If a threshold crossing has not yet occurred and the Chandeleurs do recover from the impact of Hurricane Katrina, it remains uncertain how imminent a threshold crossing may be. To better understand the potential future evolution of the Chandeleur Islands and to assess the combination of factors that are likely to cause a threshold crossing in this environment, a series of initial model experiments are being conducted using the morphological-behavior model GEOMBEST. This model simulates the evolution of coastal morphology and stratigraphy resulting from changes in relative sea level and sediment supply, and provides insight into how barriers evolve over time scales ranging from decades to millennia. Vibracore logs, geophysical records, bathymetric surveys, and lidar surveys provide data necessary to design the model domain, while sediment budget studies, estimates of sea-level rise rates, and measurements of shoreline change rates provide input and calibration parameters. Late Holocene model runs simulate the evolution of 42 km-long North Chandeleur Island as it migrated from the distal end of the St. Bernard Delta to its modern position. Building on the late Holocene simulation, we present a series of initial, multi-decadal forward model experiments that assess the combination of factors, including relative sea-level rise rates, sediment supply rates, and geologic framework, that are likely to initiate a threshold crossing in the Chandeleur Islands.

Copper uptake by the water hyacinth. [Eichornia crassipes

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

Lee, T.A.; Hardy, J.K.

1987-01-01

Factors affecting Cu/sup +2/ uptake by the water hyacinth (Eichornia crassipes) were examined. Two phases of copper uptake were observed throughout the uptake range (1-1000 mg/1). An initial rapid uptake phase of 4 hours followed by a slower, near linear uptake phase extending past 48 hours was observed. Stirring the solution enhanced uptake, suggesting copper removal is partially diffusion limited. Variations in pH over the range of 3 to 10 did not significantly affect uptake. Increasing the root mass of the plant increased the amount of copper taken up. As solution volume was increased more copper was removed. The presencemore » of complexing agents during the uptake phase reduced copper uptake. The inability of complexing agents to recover all copper initially removed by a plant suggests a migration to sites within the plant.« less

Factors influencing the development of a biostimulant for the in-situ anaerobic dechlorination of polychlorinated biphenyls in Fox River, Wisconsin sediments

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

Hollifield, M.B.; Park, J.K.; Boyle, W.C.

1995-12-31

Polychlorinated biphenyl (PCB) contaminated sediments were collected from the Fox River, Wisconsin, and analyzed for the possible occurrence of reductive dechlorination. Evidence of in-situ dechlorination was observed. However, the extent of this in-situ dechlorination was less than that typically reported in the literature, suggesting that stimulation of further dechlorination was possible. The use of nutrients and surfactants was explored for stimulating additional dechlorination. The nutrient amendment reported here was found to be inhibitory. Surfactants had varying effect, but non significantly improved dechlorination over control treatments. The most significant factors were observed to be the initial extent of dechlorination and PCBmore » concentration. Additional dechlorination was most likely to be observed in sediments with higher PCB concentration and less initial dechlorination. All sediments converged on a common dechlorination level regardless of the initial state of the sediments.« less

Processes regulating the initiation and postejaculatory resumption of copulatory behavior in male hamsters.

PubMed

Floody, Owen R

2014-06-01

Studies using factor analysis have helped describe the organization of copulatory behavior in male rodents. However, the focus of these studies on a few traditional measures may have limited their results. To test this possibility, 74 sexually-experienced male hamsters were observed as they copulated with stimulus females. The measures collected exceeded the conventional ones in number, variety and independence. The factor analysis of these data revealed a structure with seven factors collectively accounting for 80% of the variance. Most resembled the factors in previous reports, reinforcing the contributions that the processes suggested by these factors make to the organization of male behavior. But several other factors were more novel, possibly reflecting the use of measures that were novel or revised for greater independence. The most interesting of these were two factors focusing on early steps in the progression leading to ejaculation. Importantly, both incorporated measures from each of the three copulatory series that were observed. Past work suggests that independent processes control the times required to initiate copulation and later resume it after an ejaculation. In contrast, these results suggest the existence of two processes, each of which contributes to both the initiation and reinitiation of copulation. Copyright © 2014 Elsevier B.V. All rights reserved.

Elucidating the role of vegetation in the initiation of rainfall-induced shallow landslides: Insights from an extreme rainfall event in the Colorado Front Range

USGS Publications Warehouse

McGuire, Luke; Rengers, Francis K.; Kean, Jason W.; Coe, Jeffrey A.; Mirus, Benjamin B.; Baum, Rex L.; Godt, Jonathan W.

2016-01-01

More than 1100 debris flows were mobilized from shallow landslides during a rainstorm from 9 to 13 September 2013 in the Colorado Front Range, with the vast majority initiating on sparsely vegetated, south facing terrain. To investigate the physical processes responsible for the observed aspect control, we made measurements of soil properties on a densely forested north facing hillslope and a grassland-dominated south facing hillslope in the Colorado Front Range and performed numerical modeling of transient changes in soil pore water pressure throughout the rainstorm. Using the numerical model, we quantitatively assessed interactions among vegetation, rainfall interception, subsurface hydrology, and slope stability. Results suggest that apparent cohesion supplied by roots was responsible for the observed connection between debris flow initiation and slope aspect. Results suggest that future climate-driven modifications to forest structure could substantially influence landslide hazards throughout the Front Range and similar water-limited environments where vegetation communities may be more susceptible to small variations in climate.

Improving Air Quality Forecasts with AURA Observations

NASA Technical Reports Server (NTRS)

Newchurch, M. J.; Biazer, A.; Khan, M.; Koshak, W. J.; Nair, U.; Fuller, K.; Wang, L.; Parker, Y.; Williams, R.; Liu, X.

2008-01-01

Past studies have identified model initial and boundary conditions as sources of reducible errors in air-quality simulations. In particular, improving the initial condition improves the accuracy of short-term forecasts as it allows for the impact of local emissions to be realized by the model and improving boundary conditions improves long range transport through the model domain, especially in recirculating anticyclones. During the August 2006 period, we use AURA/OMI ozone measurements along with MODIS and CALIPSO aerosol observations to improve the initial and boundary conditions of ozone and Particulate Matter. Assessment of the model by comparison of the control run and satellite assimilation run to the IONS06 network of ozonesonde observations, which comprise the densest ozone sounding campaign ever conducted in North America, to AURA/TES ozone profile measurements, and to the EPA ground network of ozone and PM measurements will show significant improvement in the CMAQ calculations that use AURA initial and boundary conditions. Further analyses of lightning occurrences from ground and satellite observations and AURA/OMI NO2 column abundances will identify the lightning NOx signal evident in OMI measurements and suggest pathways for incorporating the lightning and NO2 data into the CMAQ simulations.

Will Arctic sea ice thickness initialization improve seasonal forecast skill?

NASA Astrophysics Data System (ADS)

Day, J. J.; Hawkins, E.; Tietsche, S.

2014-11-01

Arctic sea ice thickness is thought to be an important predictor of Arctic sea ice extent. However, coupled seasonal forecast systems do not generally use sea ice thickness observations in their initialization and are therefore missing a potentially important source of additional skill. To investigate how large this source is, a set of ensemble potential predictability experiments with a global climate model, initialized with and without knowledge of the sea ice thickness initial state, have been run. These experiments show that accurate knowledge of the sea ice thickness field is crucially important for sea ice concentration and extent forecasts up to 8 months ahead, especially in summer. Perturbing sea ice thickness also has a significant impact on the forecast error in Arctic 2 m temperature a few months ahead. These results suggest that advancing capabilities to observe and assimilate sea ice thickness into coupled forecast systems could significantly increase skill.

Modeling nearshore morphological evolution at seasonal scale

USGS Publications Warehouse

Walstra, D.-J.R.; Ruggiero, P.; Lesser, G.; Gelfenbaum, G.

2006-01-01

A process-based model is compared with field measurements to test and improve our ability to predict nearshore morphological change at seasonal time scales. The field experiment, along the dissipative beaches adjacent to Grays Harbor, Washington USA, successfully captured the transition between the high-energy erosive conditions of winter and the low-energy beach-building conditions typical of summer. The experiment documented shoreline progradation on the order of 20 m and as much as 175 m of onshore bar migration. Significant alongshore variability was observed in the morphological response of the sandbars over a 4 km reach of coast. A detailed sensitivity analysis suggests that the model results are more sensitive to adjusting the sediment transport associated with asymmetric oscillatory wave motions than to adjusting the transport due to mean currents. Initial results suggest that alongshore variations in the initial bathymetry are partially responsible for the observed alongshore variable morphological response during the experiment. Copyright ASCE 2006.

Influence and Modeling of Residual Stresses in Thick Walled Pressure Vessels with Through Holes

DTIC Science & Technology

2012-02-28

9 FIGURE 4 ENVIRONMENTAL CRACKING OBSERVED IN EVACUATOR HOLE .......... 9 FIGURE 5 STRESSES PRESENT IN STRAIGHT EVACUATOR... ASSESMENT OF INITIAL DAMAGE Through investigation was undertaken on vessels similar in size and strength level to pressure vessels 85A and 85B...suggesting that the source of the residual stresses required to initiate and propagate these environmental cracks is not a resultant of the typical

Stress and death of cnidarian host cells play a role in cnidarian bleaching.

PubMed

Paxton, Camille W; Davy, Simon K; Weis, Virginia M

2013-08-01

Coral bleaching occurs when there is a breakdown of the symbiosis between cnidarian hosts and resident Symbiodinium spp. Multiple mechanisms for the bleaching process have been identified, including apoptosis and autophagy, and most previous work has focused on the Symbiodinium cell as the initiator of the bleaching cascade. In this work we show that it is possible for host cells to initiate apoptosis that can contribute to death of the Symbiodinium cell. First we found that colchicine, which results in apoptosis in other animals, causes cell death in the model anemone Aiptasia sp. but not in cultured Symbiodinium CCMP-830 cells or in cells freshly isolated from host Aiptasia (at least within the time frame of our study). In contrast, when symbiotic Aiptasia were incubated in colchicine, cell death in the resident Symbiodinium cells was observed, suggesting a host effect on symbiont mortality. Using live-cell confocal imaging of macerated symbiotic host cell isolates, we identified a pattern where the initiation of host cell death was followed by mortality of the resident Symbiodinium cells. This same pattern was observed in symbiotic host cells that were subjected to temperature stress. This research suggests that mortality of symbionts during temperature-induced bleaching can be initiated in part by host cell apoptosis.

Shock initiation of nitromethane

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

Yoo, C.S.; Holmes, N.C.

1993-12-31

The shock initiation processes of nitromethane have been examined by using a fast time-resolved emission spectroscopy at a two-stage gas gun. a broad, but strong emission has been observed in a spectral range between 350 and 700 nm from shocked nitromethane above 9 GPa. The temporal profile suggests that shocked nitromethane detonates through three characteristic periods, namely an induction period, a hock initiation period, and a thermal explosion period. This paper discusses temporal and chemical characteristics of these periods and present the temperature of the shock-detonating nitromethane at pressures between 9 and 15 GPa.

Genetic diversity of a newly established population of golden eagles on the Channel Islands, California

USGS Publications Warehouse

Sonsthagen, Sarah A.; Coonan, Timothy J.; Latta, Brian C.; Sage, George K.; Talbot, Sandra L.

2012-01-01

Gene flow can have profound effects on the genetic diversity of a founding population depending on the number and relationship among colonizers and the duration of the colonization event. Here we used data from nuclear microsatellite and mitochondrial DNA control region loci to assess genetic diversity in golden eagles of the recently colonized Channel Islands, California. Genetic diversity in the Channel Island population was low, similar to signatures observed for other recent colonizing island populations. Differences in levels of genetic diversity and structure observed between mainland California and the islands suggests that few individuals were involved in the initial founding event, and may have comprised a family group. The spatial genetic structure observed between Channel Island and mainland California golden eagle populations across marker types, and genetic signature of population decline observed for the Channel Island population, suggest a single or relatively quick colonization event. Polarity in gene flow estimates based on mtDNA confirm an initial colonization of the Channel Islands by mainland golden eagles, but estimates from microsatellite data suggest that golden eagles on the islands were dispersing more recently to the mainland, possibly after reaching the carrying capacity of the island system. These results illustrate the strength of founding events on the genetic diversity of a population, and confirm that changes to genetic diversity can occur within just a few generations.

A Simple Method for Automated Equilibration Detection in Molecular Simulations.

PubMed

Chodera, John D

2016-04-12

Molecular simulations intended to compute equilibrium properties are often initiated from configurations that are highly atypical of equilibrium samples, a practice which can generate a distinct initial transient in mechanical observables computed from the simulation trajectory. Traditional practice in simulation data analysis recommends this initial portion be discarded to equilibration, but no simple, general, and automated procedure for this process exists. Here, we suggest a conceptually simple automated procedure that does not make strict assumptions about the distribution of the observable of interest in which the equilibration time is chosen to maximize the number of effectively uncorrelated samples in the production timespan used to compute equilibrium averages. We present a simple Python reference implementation of this procedure and demonstrate its utility on typical molecular simulation data.

A simple method for automated equilibration detection in molecular simulations

PubMed Central

Chodera, John D.

2016-01-01

Molecular simulations intended to compute equilibrium properties are often initiated from configurations that are highly atypical of equilibrium samples, a practice which can generate a distinct initial transient in mechanical observables computed from the simulation trajectory. Traditional practice in simulation data analysis recommends this initial portion be discarded to equilibration, but no simple, general, and automated procedure for this process exists. Here, we suggest a conceptually simple automated procedure that does not make strict assumptions about the distribution of the observable of interest, in which the equilibration time is chosen to maximize the number of effectively uncorrelated samples in the production timespan used to compute equilibrium averages. We present a simple Python reference implementation of this procedure, and demonstrate its utility on typical molecular simulation data. PMID:26771390

Boreal Summer ISO hindcast experiment: preliminary results from SNU

NASA Astrophysics Data System (ADS)

Heo, S.; Kang, I.; Kim, D.; Ham, Y.

2010-12-01

As a part of internationally coordinated research program, hindcast experiments with focus on boreal summer intraseasonal oscillation (ISO) have been done in Seoul National University (SNU). This study aims to show preliminary results from SNU’s efforts. The ISO prediction system used in the hindcast experiment consists of SNU coupled model and SNU initialization method. The SNU coupled model is an ocean-atmosphere coupled model which couples the SNU Atmospheric GCM (SNU AGCM) to the Modular Ocean Model ver.2.2 (MOM2.2) Ocean GCM developed at Geophysical Fluid Dynamics Laboratory (GFDL). In the SNU initialization method, both atmospheric and oceanic states are nudged toward reanalysis data (ERAinterim and GODAS) before prediction starting date. For the results here, 2 ensemble members are generated by using different nudging period, 8 and 9 days, respectively. The initial dates of 45-day predictions are the 1st, 11th, 21st of months during boreal summer season (May to October). Prediction skills and its dependency on the initial amplitude, the initial phase, and the number of ensemble members are investigated using the Real-time Multivariate MJO (RMM) index suggested by Wheeler and Hendon (2004). It is shown in our hindcast experiment that, after 13 forecast lead days (the forecast skill is about 0.7), the prediction skill does not depend on the strength of the initial state. Also, we found that the prediction skill has a phase dependency. The prediction skill is particularly low when the convective center related to the MJO is over the Indian Ocean (phase 2). The ensemble prediction has more improved correlation skill than each member. To better understand the phase dependency, we compared the observed and predicted behavior of the MJO that propagates from different starting phases. The phase speed of the prediction is slower than the observation. The MJO in the hindcast experiment propagates with weaker amplitudes than observed except for initial phase 3. Also investigated is the climatology and anomalies of precipitable water to understand the difference of the propagation. The difference between observed and predicted climatology shows strong dry bias over the eastern Indian Ocean, in where convective anomalies are not properly developed in hindcast data, especially those from initial phase 2. Our results suggest possible impacts of mean bias on prediction skills of the MJO.

The Individualized Classroom Assessment Scoring System (inCLASS): Preliminary Reliability and Validity of a System for Observing Preschoolers’ Competence in Classroom Interactions

PubMed Central

Downer, Jason T.; Booren, Leslie M.; Lima, Olivia K.; Luckner, Amy E.; Pianta, Robert C.

2012-01-01

This paper introduces the Individualized Classroom Assessment Scoring System (inCLASS), an observation tool that targets children’s interactions in preschool classrooms with teachers, peers, and tasks. In particular, initial evidence is reported of the extent to which the inCLASS meets the following psychometric criteria: inter-rater reliability, normal distributions and adequate range, construct validity, and criterion-related validity. These initial findings suggest that the inCLASS has the potential to provide an authentic, contextualized assessment of young children’s classroom behaviors. Future directions for research with the inCLASS are discussed. PMID:23175598

The effects of a flexible visual acuity-driven ranibizumab treatment regimen in age-related macular degeneration: outcomes of a drug and disease model.

PubMed

Holz, Frank G; Korobelnik, Jean-François; Lanzetta, Paolo; Mitchell, Paul; Schmidt-Erfurth, Ursula; Wolf, Sebastian; Markabi, Sabri; Schmidli, Heinz; Weichselberger, Andreas

2010-01-01

Differences in treatment responses to ranibizumab injections observed within trials involving monthly (MARINA and ANCHOR studies) and quarterly (PIER study) treatment suggest that an individualized treatment regimen may be effective in neovascular age-related macular degeneration. In the present study, a drug and disease model was used to evaluate the impact of an individualized, flexible treatment regimen on disease progression. For visual acuity (VA), a model was developed on the 12-month data from ANCHOR, MARINA, and PIER. Data from untreated patients were used to model patient-specific disease progression in terms of VA loss. Data from treated patients from the period after the three initial injections were used to model the effect of predicted ranibizumab vitreous concentration on VA loss. The model was checked by comparing simulations of VA outcomes after monthly and quarterly injections during this period with trial data. A flexible VA-guided regimen (after the three initial injections) in which treatment is initiated by loss of >5 letters from best previously observed VA scores was simulated. Simulated monthly and quarterly VA-guided regimens showed good agreement with trial data. Simulation of VA-driven individualized treatment suggests that this regimen, on average, sustains the initial gains in VA seen in clinical trials at month 3. The model predicted that, on average, to maintain initial VA gains, an estimated 5.1 ranibizumab injections are needed during the 9 months after the three initial monthly injections, which amounts to a total of 8.1 injections during the first year. A flexible, individualized VA-guided regimen after the three initial injections may sustain vision improvement with ranibizumab and could improve cost-effectiveness and convenience and reduce drug administration-associated risks.

Evidence for debris flow gully formation initiated by shallow subsurface water on Mars

USGS Publications Warehouse

Lanza, N.L.; Meyer, G.A.; Okubo, C.H.; Newsom, Horton E.; Wiens, R.C.

2010-01-01

The morphologies of some martian gullies appear similar to terrestrial features associated with debris flow initiation, erosion, and deposition. On Earth, debris flows are often triggered by shallow subsurface throughflow of liquid water in slope-mantling colluvium. This flow causes increased levels of pore pressure and thus decreased shear strength, which can lead to slide failure of slope materials and subsequent debris flow. The threshold for pore pressure-induced failure creates a distinct relationship between the contributing area supplying the subsurface flow and the slope gradient. To provide initial tests of a similar debris flow initiation hypothesis for martian gullies, measurements of the contributing areas and slope gradients were made at the channel heads of martian gullies seen in three HiRISE stereo pairs. These gullies exhibit morphologies suggestive of debris flows such as leveed channels and lobate debris fans, and have well-defined channel heads and limited evidence for multiple flows. Our results show an area-slope relationship for these martian gullies that is consistent with that observed for terrestrial gullies formed by debris flow, supporting the hypothesis that these gullies formed as the result of saturation of near-surface regolith by a liquid. This model favors a source of liquid that is broadly distributed within the source area and shallow; we suggest that such liquid could be generated by melting of broadly distributed icy materials such as snow or permafrost. This interpretation is strengthened by observations of polygonal and mantled terrain in the study areas, which are both suggestive of near-surface ice. ?? 2009 Elsevier Inc.

Measurement of long-range angular correlations and azimuthal anisotropies in high-multiplicity p + Au collisions at s NN = 200 GeV

DOE PAGES

Aidala, C.; Akiba, Y.; Alfred, M.; ...

2017-03-24

Inmore » this paper, we present measurements of long-range angular correlations and the transverse momentum dependence of elliptic flow ν 2 in high-multiplicity p + Au collisions at s NN = 200 GeV. A comparison of these results to previous measurements in high-multiplicity d + Au and 3He + Au collisions demonstrates a relation between ν 2 and the initial collision eccentricity ε 2, suggesting that the observed momentum-space azimuthal anisotropies in these small systems have a collective origin and reflect the initial geometry. Good agreement is observed between the measured ν 2 and hydrodynamic calculations for all systems, and an argument disfavoring theoretical explanations based on initial momentum-space domain correlations is presented. Finally, the set of measurements presented here allows us to leverage the distinct intrinsic geometry of each of these systems to distinguish between different theoretical descriptions of the long-range correlations observed in small collision systems.« less

Measurement of long-range angular correlations and azimuthal anisotropies in high-multiplicity p + Au collisions at s NN = 200 GeV

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

Aidala, C.; Akiba, Y.; Alfred, M.

Inmore » this paper, we present measurements of long-range angular correlations and the transverse momentum dependence of elliptic flow ν 2 in high-multiplicity p + Au collisions at s NN = 200 GeV. A comparison of these results to previous measurements in high-multiplicity d + Au and 3He + Au collisions demonstrates a relation between ν 2 and the initial collision eccentricity ε 2, suggesting that the observed momentum-space azimuthal anisotropies in these small systems have a collective origin and reflect the initial geometry. Good agreement is observed between the measured ν 2 and hydrodynamic calculations for all systems, and an argument disfavoring theoretical explanations based on initial momentum-space domain correlations is presented. Finally, the set of measurements presented here allows us to leverage the distinct intrinsic geometry of each of these systems to distinguish between different theoretical descriptions of the long-range correlations observed in small collision systems.« less

Measurement of long-range angular correlations and azimuthal anisotropies in high-multiplicity p +Au collisions at √{sNN}=200 GeV

NASA Astrophysics Data System (ADS)

Aidala, C.; Akiba, Y.; Alfred, M.; Andrieux, V.; Aoki, K.; Apadula, N.; Asano, H.; Ayuso, C.; Azmoun, B.; Babintsev, V.; Bandara, N. S.; Barish, K. N.; Bathe, S.; Bazilevsky, A.; Beaumier, M.; Belmont, R.; Berdnikov, A.; Berdnikov, Y.; Blau, D. S.; Boer, M.; Bok, J. S.; Brooks, M. L.; Bryslawskyj, J.; Bumazhnov, V.; Butler, C.; Campbell, S.; Canoa Roman, V.; Cervantes, R.; Chi, C. Y.; Chiu, M.; Choi, I. J.; Choi, J. B.; Citron, Z.; Connors, M.; Cronin, N.; Csanád, M.; Csörgő, T.; Danley, T. W.; Daugherity, M. S.; David, G.; Deblasio, K.; Dehmelt, K.; Denisov, A.; Deshpande, A.; Desmond, E. J.; Dion, A.; Dixit, D.; Do, J. H.; Drees, A.; Drees, K. A.; Dumancic, M.; Durham, J. M.; Durum, A.; Elder, T.; Enokizono, A.; En'yo, H.; Esumi, S.; Fadem, B.; Fan, W.; Feege, N.; Fields, D. E.; Finger, M.; Finger, M.; Fokin, S. L.; Frantz, J. E.; Franz, A.; Frawley, A. D.; Fukuda, Y.; Gal, C.; Gallus, P.; Garg, P.; Ge, H.; Giordano, F.; Goto, Y.; Grau, N.; Greene, S. V.; Grosse Perdekamp, M.; Gunji, T.; Guragain, H.; Hachiya, T.; Haggerty, J. S.; Hahn, K. I.; Hamagaki, H.; Hamilton, H. F.; Han, S. Y.; Hanks, J.; Hasegawa, S.; Haseler, T. O. S.; He, X.; Hemmick, T. K.; Hill, J. C.; Hill, K.; Hollis, R. S.; Homma, K.; Hong, B.; Hoshino, T.; Hotvedt, N.; Huang, J.; Huang, S.; Imai, K.; Imrek, J.; Inaba, M.; Iordanova, A.; Isenhower, D.; Ito, Y.; Ivanishchev, D.; Jacak, B. V.; Jezghani, M.; Ji, Z.; Jiang, X.; Johnson, B. M.; Jorjadze, V.; Jouan, D.; Jumper, D. S.; Kang, J. H.; Kapukchyan, D.; Karthas, S.; Kawall, D.; Kazantsev, A. V.; Khachatryan, V.; Khanzadeev, A.; Kim, C.; Kim, D. J.; Kim, E.-J.; Kim, M. H.; Kim, M.; Kincses, D.; Kistenev, E.; Klatsky, J.; Kline, P.; Koblesky, T.; Kotov, D.; Kudo, S.; Kurita, K.; Kwon, Y.; Lajoie, J. G.; Lallow, E. O.; Lebedev, A.; Lee, S.; Leitch, M. J.; Leung, Y. H.; Lewis, N. A.; Li, X.; Lim, S. H.; Liu, L. D.; Liu, M. X.; Loggins, V.-R.; Loggins, V.-R.; Lovasz, K.; Lynch, D.; Majoros, T.; Makdisi, Y. I.; Makek, M.; Malaev, M.; Manko, V. I.; Mannel, E.; Masuda, H.; McCumber, M.; McGaughey, P. L.; McGlinchey, D.; McKinney, C.; Mendoza, M.; Mignerey, A. C.; Mihalik, D. E.; Milov, A.; Mishra, D. K.; Mitchell, J. T.; Mitsuka, G.; Miyasaka, S.; Mizuno, S.; Montuenga, P.; Moon, T.; Morrison, D. P.; Morrow, S. I. M.; Murakami, T.; Murata, J.; Nagai, K.; Nagashima, K.; Nagashima, T.; Nagle, J. L.; Nagy, M. I.; Nakagawa, I.; Nakagomi, H.; Nakano, K.; Nattrass, C.; Niida, T.; Nouicer, R.; Novák, T.; Novitzky, N.; Novotny, R.; Nyanin, A. S.; O'Brien, E.; Ogilvie, C. A.; Orjuela Koop, J. D.; Osborn, J. D.; Oskarsson, A.; Ottino, G. J.; Ozawa, K.; Pantuev, V.; Papavassiliou, V.; Park, J. S.; Park, S.; Pate, S. F.; Patel, M.; Peng, W.; Perepelitsa, D. V.; Perera, G. D. N.; Peressounko, D. Yu.; Perezlara, C. E.; Perry, J.; Petti, R.; Phipps, M.; Pinkenburg, C.; Pisani, R. P.; Pun, A.; Purschke, M. L.; Read, K. F.; Reynolds, D.; Riabov, V.; Riabov, Y.; Richford, D.; Rinn, T.; Rolnick, S. D.; Rosati, M.; Rowan, Z.; Runchey, J.; Safonov, A. S.; Sakaguchi, T.; Sako, H.; Samsonov, V.; Sarsour, M.; Sato, K.; Sato, S.; Schaefer, B.; Schmoll, B. K.; Sedgwick, K.; Seidl, R.; Sen, A.; Seto, R.; Sexton, A.; Sharma, D.; Shein, I.; Shibata, T.-A.; Shigaki, K.; Shimomura, M.; Shioya, T.; Shukla, P.; Sickles, A.; Silva, C. L.; Silvermyr, D.; Singh, B. K.; Singh, C. P.; Singh, V.; Slunečka, M.; Smith, K. L.; Snowball, M.; Soltz, R. A.; Sondheim, W. E.; Sorensen, S. P.; Sourikova, I. V.; Stankus, P. W.; Stoll, S. P.; Sugitate, T.; Sukhanov, A.; Sumita, T.; Sun, J.; Syed, S.; Sziklai, J.; Takeda, A.; Tanida, K.; Tannenbaum, M. J.; Tarafdar, S.; Tarnai, G.; Tieulent, R.; Timilsina, A.; Todoroki, T.; Tomášek, M.; Towell, C. L.; Towell, R. S.; Tserruya, I.; Ueda, Y.; Ujvari, B.; van Hecke, H. W.; Vazquez-Carson, S.; Velkovska, J.; Virius, M.; Vrba, V.; Vukman, N.; Wang, X. R.; Wang, Z.; Watanabe, Y.; Watanabe, Y. S.; Wong, C. P.; Woody, C. L.; Xu, C.; Xu, Q.; Xue, L.; Yalcin, S.; Yamaguchi, Y. L.; Yamamoto, H.; Yanovich, A.; Yin, P.; Yoo, J. H.; Yoon, I.; Yu, H.; Yushmanov, I. E.; Zajc, W. A.; Zelenski, A.; Zharko, S.; Zou, L.; Phenix Collaboration

2017-03-01

We present measurements of long-range angular correlations and the transverse momentum dependence of elliptic flow v2 in high-multiplicity p +Au collisions at √{s NN}=200 GeV. A comparison of these results to previous measurements in high-multiplicity d +Au and 3He+Au collisions demonstrates a relation between v2 and the initial collision eccentricity ɛ2, suggesting that the observed momentum-space azimuthal anisotropies in these small systems have a collective origin and reflect the initial geometry. Good agreement is observed between the measured v2 and hydrodynamic calculations for all systems, and an argument disfavoring theoretical explanations based on initial momentum-space domain correlations is presented. The set of measurements presented here allows us to leverage the distinct intrinsic geometry of each of these systems to distinguish between different theoretical descriptions of the long-range correlations observed in small collision systems.

Growth inhibition at the ice prismatic plane induced by a spruce budworm antifreeze protein: a molecular dynamics simulation study.

PubMed

Nada, H; Furukawa, Y

2011-11-28

A molecular dynamics simulation was conducted to investigate the growth kinetics at the ice prismatic interface to which a spruce budworm antifreeze protein was bound. Two initial binding conformations of the protein at the interface--one energetically stable and the other energetically unstable--were examined. For both binding conformations, the growth of ice was observed around the protein. A sharp decrease in the rate of ice growth was observed around the protein that initially had the energetically stable binding conformation. Simulation results suggest that the observed decrease in the ice growth rate was attributable to melting point depression caused by the Gibbs-Thomson effect. The protein that initially had the energetically unstable binding conformation markedly relaxed so as to stably bind to the prismatic plane interface of the grown ice; thereafter, a decrease in the ice growth rate was observed as well. However, the binding conformation that the protein approached during the relaxation was different from that of the protein that initially had the energetically stable binding conformation. Thus, the simulation indicates the existence of two binding conformations for inducing a decrease in the ice growth rate. The results are possibly related to the hyperactivity of a spruce budworm antifreeze protein in real systems.

Studies with spike initiators - Linearization by noise allows continuous signal modulation in neural networks

NASA Technical Reports Server (NTRS)

Yu, Xiaolong; Lewis, Edwin R.

1989-01-01

It is shown that noise can be an important element in the translation of neuronal generator potentials (summed inputs) to neuronal spike trains (outputs), creating or expanding a range of amplitudes over which the spike rate is proportional to the generator potential amplitude. Noise converts the basically nonlinear operation of a spike initiator into a nearly linear modulation process. This linearization effect of noise is examined in a simple intuitive model of a static threshold and in a more realistic computer simulation of spike initiator based on the Hodgkin-Huxley (HH) model. The results are qualitatively similar; in each case larger noise amplitude results in a larger range of nearly linear modulation. The computer simulation of the HH model with noise shows linear and nonlinear features that were earlier observed in spike data obtained from the VIIIth nerve of the bullfrog. This suggests that these features can be explained in terms of spike initiator properties, and it also suggests that the HH model may be useful for representing basic spike initiator properties in vertebrates.

Design principles of paradoxical signaling in the immune system

NASA Astrophysics Data System (ADS)

Hart, Yuval

A widespread feature of cell-cell signaling systems is paradoxical pleiotropy: the same secreted signaling molecule can induce opposite effects in the responding cells. For example, the cytokine IL-2 can promote proliferation and death of T-cells. The role of such paradoxical signaling remains unclear. We suggest that this mechanism provides homeostatic concentration of cells, independent of initial conditions. The crux of the paradoxical mechanism is the combination of a positive and a negative feedback loops creating two stable states - an OFF state and an ON state. Experimentally, we found that CD4 + cells grown in culture with a 30-fold difference in initial concentrations reached a homeostatic concentration nearly independent of initial cell levels (ON-state). Below an initial threshold, cell density decayed to extinction (OFF-state). Mathematical modeling explained the observed cell and cytokine dynamics and predicted conditions that shifted cell fate from homeostasis to the OFF-state. We suggest that paradoxical signaling provides cell circuits with specific dynamical features that are robust to environmental perturbations.

Effect of advective flow in fractures and matrix diffusion on natural gas production

DOE PAGES

Karra, Satish; Makedonska, Nataliia; Viswanathan, Hari S.; ...

2015-10-12

Although hydraulic fracturing has been used for natural gas production for the past couple of decades, there are significant uncertainties about the underlying mechanisms behind the production curves that are seen in the field. A discrete fracture network based reservoir-scale work flow is used to identify the relative effect of flow of gas in fractures and matrix diffusion on the production curve. With realistic three dimensional representations of fracture network geometry and aperture variability, simulated production decline curves qualitatively resemble observed production decline curves. The high initial peak of the production curve is controlled by advective fracture flow of freemore » gas within the network and is sensitive to the fracture aperture variability. Matrix diffusion does not significantly affect the production decline curve in the first few years, but contributes to production after approximately 10 years. These results suggest that the initial flushing of gas-filled background fractures combined with highly heterogeneous flow paths to the production well are sufficient to explain observed initial production decline. Lastly, these results also suggest that matrix diffusion may support reduced production over longer time frames.« less

Possible evidence for the existence of antimatter on a cosmological scale in the universe.

NASA Technical Reports Server (NTRS)

Stecker, F. W.; Morgan, D. L., Jr.; Bredekamp, J.

1971-01-01

Initial results of a detailed calculation of the cosmological gamma-ray spectrum from matter-antimatter annihilation in the universe. The similarity between the calculated spectrum and the present observations of the gamma-ray background spectrum above 1 MeV suggests that such observations may be evidence of the existence of antimatter on a large scale in the universe.

Full-field and anomaly initialization using a low-order climate model: a comparison and proposals for advanced formulations

NASA Astrophysics Data System (ADS)

Carrassi, A.; Weber, R. J. T.; Guemas, V.; Doblas-Reyes, F. J.; Asif, M.; Volpi, D.

2014-04-01

Initialization techniques for seasonal-to-decadal climate predictions fall into two main categories; namely full-field initialization (FFI) and anomaly initialization (AI). In the FFI case the initial model state is replaced by the best possible available estimate of the real state. By doing so the initial error is efficiently reduced but, due to the unavoidable presence of model deficiencies, once the model is let free to run a prediction, its trajectory drifts away from the observations no matter how small the initial error is. This problem is partly overcome with AI where the aim is to forecast future anomalies by assimilating observed anomalies on an estimate of the model climate. The large variety of experimental setups, models and observational networks adopted worldwide make it difficult to draw firm conclusions on the respective advantages and drawbacks of FFI and AI, or to identify distinctive lines for improvement. The lack of a unified mathematical framework adds an additional difficulty toward the design of adequate initialization strategies that fit the desired forecast horizon, observational network and model at hand. Here we compare FFI and AI using a low-order climate model of nine ordinary differential equations and use the notation and concepts of data assimilation theory to highlight their error scaling properties. This analysis suggests better performances using FFI when a good observational network is available and reveals the direct relation of its skill with the observational accuracy. The skill of AI appears, however, mostly related to the model quality and clear increases of skill can only be expected in coincidence with model upgrades. We have compared FFI and AI in experiments in which either the full system or the atmosphere and ocean were independently initialized. In the former case FFI shows better and longer-lasting improvements, with skillful predictions until month 30. In the initialization of single compartments, the best performance is obtained when the stabler component of the model (the ocean) is initialized, but with FFI it is possible to have some predictive skill even when the most unstable compartment (the extratropical atmosphere) is observed. Two advanced formulations, least-square initialization (LSI) and exploring parameter uncertainty (EPU), are introduced. Using LSI the initialization makes use of model statistics to propagate information from observation locations to the entire model domain. Numerical results show that LSI improves the performance of FFI in all the situations when only a portion of the system's state is observed. EPU is an online drift correction method in which the drift caused by the parametric error is estimated using a short-time evolution law and is then removed during the forecast run. Its implementation in conjunction with FFI allows us to improve the prediction skill within the first forecast year. Finally, the application of these results in the context of realistic climate models is discussed.

Sex Differences in Antiretroviral Therapy Initiation in Pediatric HIV Infection

PubMed Central

Swordy, Alice; Mori, Luisa; Laker, Leana; Muenchhoff, Maximilian; Matthews, Philippa C.; Tudor-Williams, Gareth; Lavandier, Nora; van Zyl, Anriette; Hurst, Jacob; Walker, Bruce D.; Ndung’u, Thumbi; Prendergast, Andrew; Goulder, Philip; Jooste, Pieter

2015-01-01

The incidence and severity of infections in childhood is typically greater in males. The basis for these observed sex differences is not well understood, and potentially may facilitate novel approaches to reducing disease from a range of conditions. We here investigated sex differences in HIV-infected children in relation to antiretroviral therapy (ART) initiation and post-treatment outcome. In a South African cohort of 2,101 HIV-infected children, we observed that absolute CD4+ count and CD4% were significantly higher in ART-naïve female, compared to age-matched male, HIV-infected children. Absolute CD4 count and CD4% were also significantly higher in HIV-uninfected female versus male neonates. We next showed that significantly more male than female children were initiated on ART (47% female); and children not meeting criteria to start ART by >5yrs were more frequently female (59%; p<0.001). Among ART-treated children, immune reconstitution of CD4 T-cells was more rapid and more complete in female children, even after adjustment for pre-ART absolute CD4 count or CD4% (p=0.011, p=0.030, respectively). However, while ART was initiated as a result of meeting CD4 criteria less often in females (45%), ART initiation as a result of clinical disease in children whose CD4 counts were above treatment thresholds occurred more often in females (57%, p<0.001). The main sex difference in morbidity observed in children initiating ART above CD4 thresholds, above that of TB disease, was as a result of wasting and stunting observed in females with above-threshold CD4 counts (p=0.002). These findings suggest the possibility that optimal treatment of HIV-infected children might incorporate differential CD4 treatment thresholds for ART initiation according to sex. PMID:26151555

Development of Ego-Resiliency: Relations to Observed Parenting and Polymorphisms in the Serotonin Transporter Gene During Early Childhood.

PubMed

Taylor, Zoe E; Sulik, Michael J; Eisenberg, Nancy; Spinrad, Tracy L; Silva, Kassondra M; Lemery-Chalfant, Kathryn; Stover, Daryn A; Verrelli, Brian C

2014-08-01

We used observed parenting behaviors, along with genetic variants and haplotypes of the serotonin transporter gene (SLC6A4), as predictors of children's ego-resiliency during early childhood ( N =153). Quality of mothers' parenting was observed at 18 months of age and mothers' reports of ego-resiliency were collected at six time points from 18 to 84 months. Genetic data were collected at 72 months. Observed parenting was positively associated with initial levels of children's ego-resiliency. Furthermore, although individual genetic variants of the serotonin transporter gene (LPR, STin2) were not associated with ego-resiliency, the S10 haplotype (that combines information from these two variants) was negatively associated with initial levels of ego-resiliency. Both parenting and serotonin genetic variation uniquely predicted children's ego-resiliency, suggesting an additive effect of genetic and parental factors.

Development of Ego-Resiliency: Relations to Observed Parenting and Polymorphisms in the Serotonin Transporter Gene During Early Childhood

PubMed Central

Taylor, Zoe E.; Sulik, Michael J.; Eisenberg, Nancy; Spinrad, Tracy L.; Silva, Kassondra M.; Lemery-Chalfant, Kathryn; Stover, Daryn A.; Verrelli, Brian C.

2013-01-01

We used observed parenting behaviors, along with genetic variants and haplotypes of the serotonin transporter gene (SLC6A4), as predictors of children’s ego-resiliency during early childhood (N =153). Quality of mothers’ parenting was observed at 18 months of age and mothers’ reports of ego-resiliency were collected at six time points from 18 to 84 months. Genetic data were collected at 72 months. Observed parenting was positively associated with initial levels of children’s ego-resiliency. Furthermore, although individual genetic variants of the serotonin transporter gene (LPR, STin2) were not associated with ego-resiliency, the S10 haplotype (that combines information from these two variants) was negatively associated with initial levels of ego-resiliency. Both parenting and serotonin genetic variation uniquely predicted children’s ego-resiliency, suggesting an additive effect of genetic and parental factors. PMID:25346579

Photoactive high explosives: linear and nonlinear photochemistry of petrin tetrazine chloride.

PubMed

Greenfield, Margo T; McGrane, Shawn D; Bolme, Cindy A; Bjorgaard, Josiah A; Nelson, Tammie R; Tretiak, Sergei; Scharff, R Jason

2015-05-21

Pentaerythritol tetranitrate (PETN), a high explosive, initiates with traditional shock and thermal mechanisms. In this study, the tetrazine-substituted derivative of PETN, pentaerythritol trinitrate chlorotetrazine (PetrinTzCl), is being investigated for a photochemical initiation mechanism that could allow control over the chemistry contributing to decomposition leading to initiation. PetrinTzCl exhibits a photochemical quantum yield (QYPC) at 532 nm not evident with PETN. Using static spectroscopic methods, we observe energy absorption on the tetrazine (Tz) ring that results in photodissociation yielding N2, Cl-CN, and Petrin-CN as the major photoproducts. The QYPC was enhanced with increasing irradiation intensity. Experiment and theoretical calculations imply this excitation mechanism follows sequential photon absorption. Dynamic simulations demonstrate that the relaxation mechanism leading to the observed photochemistry in PetrinTzCl is due to vibrational excitation during internal conversion. PetrinTzCl's single photon stability and intensity dependence suggest this material could be stable in ambient lighting, yet possible to initiate with short-pulsed lasers.

High stress shallow moonquakes - Evidence for an initially totally molten moon

NASA Technical Reports Server (NTRS)

Binder, A. B.; Oberst, J.

1985-01-01

Thermoelastic stress calculations show that if the moon was initially molten only in the outer few hundred kilometers, as in the magma ocean model of the moon, the highlands crust should be aseismic. In contrast, if the moon was initially totally molten, high stress (1 to more than about 3 kbar), shallow (0 to about 6 km deep), compressional moonquakes should be occurring in the highlands crust. Calculations of the minimum stress drops made for the 28 observed shallow moonquakes suggest that 3 of them probably have stress drops in the kbar range. Thus, these very limited seismic data are consistent with the model that the moon was initially totally molten.

Dissociation of sensitivities to tumor promotion and progression in outbred and inbred SENCAR mice.

PubMed

Gimenez-Conti, I B; Bianchi, A B; Fischer, S M; Reiners, J J; Conti, C J; Slaga, T J

1992-06-15

The sensitivity of outbred SENCAR mice and inbred SENCAR (SSIN) mice to multistage carcinogenesis was studied. Tumors were induced using either 7,12-dimethylbenz[a]anthracene or N-methyl-N'-nitro-N-nitrosoguanidine as initiators and 12-O-tetradecanoylphorbol-13-acetate or benzoyl peroxide as promoting agents. Although the number of papillomas per mouse was higher in SSIN than in outbred SENCAR mice, the number of carcinomas observed in the SSIN strain was significantly lower regardless of the initiator or promoter used. It was also observed that the expression of markers of premalignant progression (i.e., dysplasia, expression of keratin K13, and loss of keratin K1 expression) was markedly suppressed in SSIN papillomas. After 50 wk of promotion with 12-O-tetradecanoylphorbol-13-acetate, the pattern of expression of K13 and K1 in SSIN mice was comparable to the pattern observed in outbred SENCAR mice after 10 to 20 wk of promotion with 12-O-tetradecanoylphorbol-13-acetate. It was also observed that 67% of the tumors induced in SSIN mice by initiation with 7,12-dimethylbenz[a]anthracene exhibited a mutation in codon 61 of the Ha-ras-1 gene. This latter finding suggests that the differences observed in tumor progression between the inbred strain and the outbred stock are not related to a genetic alteration in the Ha-ras-1 gene but rather to an independent event that we have postulated to involve a putative suppressor gene. The data reported here suggest that the putative gene(s) that confers susceptibility to tumor promotion was segregated from the gene(s) involved in tumor progression during selection and inbreeding of the SENCAR mouse stock.

Seismic Oceanography's Failure to Flourish: A Possible Solution

NASA Astrophysics Data System (ADS)

Ruddick, B. R.

2018-01-01

A recent paper in Journal of Geophysical Research: Oceans used multichannel seismic observations to map estimates of internal wave mixing in the Gulf of Mexico, finding greatly enhanced mixing over the slope region. These results suggest that the ocean margins may supply the mixing required to close the global thermohaline circulation, and the techniques demonstrated here might be used to map mixing over much of the world's continental shelves. The use of multichannel seismics to image ocean phenomena is nearly 15 years old, and despite the initial promise, the techniques have not become as broadly used as initially expected. We discuss possible reasons for this, and suggest an alternative approach that might gain broader success.

Impact Initiation of Rods of Pressed Polytetrafluoroethylene (PTFE) and Aluminum Powders

NASA Astrophysics Data System (ADS)

Mock, Willis, Jr.

2005-07-01

A gas gun has been used to investigate the shock initiation of rods consisting of a mixture of 74 wt % PTFE (28 μm particle size) and 26 wt % aluminum (5 μm particle size) powders. The 7.6 mm diameter by 51 mm long rods were fabricated from material that had been pressed and sintered to a full density of 2.27 gm/cm^ 3. The rods were sabot-launched into 4340 steel anvils at impact velocities ranging from 104 to 777 m/s. This corresponds to calculated impact stresses of 3.3 to 48 kbar. The experiments were carried out in a 50-100 mtorr vacuum. A framing camera was used to observe the time sequence of events. These include changes in rod shape, fracture, and the initiation and evolution of the reaction phenomena. Observation of first visible light after impact was taken as the initiation time. Initiation of the reaction occurred at discrete locations in the rod material. At low velocity, no initiation occurred. Above an initiation threshold, the initiation time dropped abruptly from 56 μs just above threshold to 4 μs at the highest impact velocity. Two experiments were performed for pure PTFE material for comparison with the PTFE/Al rods. The pure PTFE showed more extensive radial flow without obvious brittle fracture. For the 784 m/s impact experiment, small points of light were observed on the edge of the mushroomed portion of the rod about 20 μs after impact, suggesting the onset of chemical reaction.

Assessment of the fetus: relevance to brain injury.

PubMed

Hill, A

1989-06-01

This article reviews recent advances in the antepartum and intrapartum assessment of the fetus and their relationship to brain injury in the newborn. The antepartum assessment involves observation of fetal body and eye movements, the nonstress and contraction stress tests, measurement of amniotic fluid volume, the fetal biophysical score and measurement of fetoplacental blood physiology. There is evidence to suggest that seizures may either be epileptic in origin or initiated and mediated by nonepileptic mechanisms. Therapeutic decisions may be based on bedside assessment of the pathophysiology of observed seizures. Although EEG/video monitoring plays a role in the management of neonatal seizures, clinical evaluation of the seizures may provide initial data critical to decisions concerning immediate management.

Viscosity effects on the thermal decomposition of bis(perfluoro-2-N-propoxypropionyl) peroxide in dense carbon dioxide and fluorinated solvents.

PubMed

Bunyard, W C; Kadla, J F; DeYoung, J; DeSimone, J M

2001-08-01

The thermal decomposition of the free-radical initiator bis(perfluoro-2-N-propoxyprionyl) peroxide (BPPP) was studied in dense carbon dioxide and a series of fluorinated solvents. For the fluorinated solvents, the observed first-order decomposition rate constants, k(obs), increased with decreasing solvent viscosity, suggesting a single-bond decomposition mechanism. The k(obs) values are comparatively larger in dense carbon dioxide and similar to the "zero-viscosity" rate constants extrapolated from the decomposition kinetics in the fluorinated solvents. The decomposition activation parameters demonstrate a compensation behavior of the activation enthalpy with the activation entropy upon change in solvent viscosity. Comparison of the change in activation parameter values upon change in solvent viscosity for BPPP with two additional initiators, acetyl peroxide (AP) and trifluoroacetyl peroxide (TFAP), further suggests that carbon dioxide exerts a very minimal influence on the decomposition mechanism of these initiators through solvent-cage effects.

Topology in two dimensions. IV - CDM models with non-Gaussian initial conditions

NASA Astrophysics Data System (ADS)

Coles, Peter; Moscardini, Lauro; Plionis, Manolis; Lucchin, Francesco; Matarrese, Sabino; Messina, Antonio

1993-02-01

The results of N-body simulations with both Gaussian and non-Gaussian initial conditions are used here to generate projected galaxy catalogs with the same selection criteria as the Shane-Wirtanen counts of galaxies. The Euler-Poincare characteristic is used to compare the statistical nature of the projected galaxy clustering in these simulated data sets with that of the observed galaxy catalog. All the models produce a topology dominated by a meatball shift when normalized to the known small-scale clustering properties of galaxies. Models characterized by a positive skewness of the distribution of primordial density perturbations are inconsistent with the Lick data, suggesting problems in reconciling models based on cosmic textures with observations. Gaussian CDM models fit the distribution of cell counts only if they have a rather high normalization but possess too low a coherence length compared with the Lick counts. This suggests that a CDM model with extra large scale power would probably fit the available data.

Dawn Auroral Breakup at Saturn Initiated by Auroral Arcs: UVIS/Cassini Beginning of Grand Finale Phase

NASA Astrophysics Data System (ADS)

Radioti, A.; Grodent, D.; Yao, Z. H.; Gérard, J.-C.; Badman, S. V.; Pryor, W.; Bonfond, B.

2017-12-01

We present Cassini auroral observations obtained on 11 November 2016 with the Ultraviolet Imaging Spectrograph at the beginning of the F-ring orbits and the Grand Finale phase of the mission. The spacecraft made a close approach to Saturn's southern pole and offered a remarkable view of the dayside and nightside aurora. With this sequence we identify, for the first time, the presence of dusk/midnight arcs, which are azimuthally spread from high to low latitudes, suggesting that their source region extends from the outer to middle/inner magnetosphere. The observed arcs could be auroral manifestations of plasma flows propagating toward the planet from the magnetotail, similar to terrestrial "auroral streamers." During the sequence the dawn auroral region brightens and expands poleward. We suggest that the dawn auroral breakup results from a combination of plasma instability and global-scale magnetic field reconfiguration, which is initiated by plasma flows propagating toward the planet. Alternatively, the dawn auroral enhancement could be triggered by tail magnetic reconnection.

Acute focal dystonia induced by a tricyclic antidepressant in a patient with Wilson disease: a case report.

PubMed

Litwin, T; Chabik, G; Członkowska, A

2013-01-01

The authors present the case of a 19-year-old patient with Wilson disease (WD) who developed symptoms of acute focal dystonia of the left hand (a 'starfish' hand presentation) shortly after treatment with the tricyclic antidepressant clomipramine. The diagnosis of WD was made 8 months earlier based on abnormal copper metabolism parameters and was confirmed by genetic testing. Initially, the patient presented with akathisia, sialorrhea, oromandibular dystonia (occasionally grimacing) and slight dysarthria. The patient's symptoms diminished after treatment with d-penicillamine was initiated. No further deterioration was observed after copper-chelating therapy was started. The authors diagnosed acute focal dystonia induced by clomipramine. Botulinum toxin and intensive rehabilitation was initiated; complete regression of hand dystonia was observed. Based on the case, the authors suggest that care should be exercised with regard to starting medications that could potentially impact the extrapyramidal system in WD patients.

Will sea ice thickness initialisation improve Arctic seasonal-to-interannual forecast skill?

NASA Astrophysics Data System (ADS)

Day, J. J.; Hawkins, E.; Tietsche, S.

2014-12-01

A number of recent studies have suggested that Arctic sea ice thickness is an important predictor of Arctic sea ice extent. However, coupled forecast systems do not currently use sea ice thickness observations in their initialization and are therefore missing a potentially important source of additional skill. A set of ensemble potential predictability experiments, with a global climate model, initialized with and without knowledge of the sea ice thickness initial state, have been run to investigate this. These experiments show that accurate knowledge of the sea ice thickness field is crucially important for sea ice concentration and extent forecasts up to eight months ahead. Perturbing sea ice thickness also has a significant impact on the forecast error in the 2m temperature and surface pressure fields a few months ahead. These results show that advancing capabilities to observe and assimilate sea ice thickness into coupled forecast systems could significantly increase skill.

Financial preconditions for successful community initiatives for the uninsured.

PubMed

Song, Paula H; Smith, Dean G

2007-01-01

Community-based initiatives are increasingly being implemented as a strategy to address the health needs of the community, with a growing body of evidence on successes of various initiatives. This study addresses financial status indicators (preconditions) that might predict where community-based initiatives might have a better chance for success. We evaluated five community-based initiatives funded by the Communities in Charge (CIC) program sponsored by the Robert Wood Johnson Foundation. These initiatives focus on increasing access by easing financial barriers to care for the uninsured. At each site, we collected information on financial status indicators and interviewed key personnel from health services delivery and financing organizations. With full acknowledgment of the caveats associated with generalizations based on a small number of observations, we suggest four financial preconditions associated with successful initiation of CIC programs: (1) uncompensated care levels that negatively affect profitability, (2) reasonable financial stability of providers, (3) stable health insurance market, and (4) the potential to create new sources of funding. In general, sites that demonstrate successful program initiation are financially stressed enough by uncompensated care to gain the attention of local healthcare providers. However, they are not so strained and so concerned about revenue sources that they cannot afford to participate in the initiative. In addition to political and managerial indicators, we suggest that planning for community-based initiatives should include financial indicators of current health services delivery and financing organizations and consideration of whether they meet preconditions for success.

Eukaryotic chaperonin containing T-complex polypeptide 1 interacts with filamentous actin and reduces the initial rate of actin polymerization in vitro

PubMed Central

Grantham, Julie; Ruddock, Lloyd W.; Roobol, Anne; Carden, Martin J.

2002-01-01

We have previously observed that subunits of the chaperonin required for actin production (type-II chaperonin containing T-complex polypeptide 1 [CCT]) localize at sites of microfilament assembly. In this article we extend this observation by showing that substantially substoichiometric CCT reduces the initial rate of pyrene-labeled actin polymerization in vitro where eubacterial chaperonin GroEL had no such effect. CCT subunits bound selectively to F-actin in cosedimentation assays, and CCT reduced elongation rates from both purified actin filament “seeds” and the short and stabilized, minus-end blocked filaments in erythrocyte membrane cytoskeletons. These observations suggest CCT might remain involved in biogenesis of the actin cytoskeleton, by acting at filament (+) ends, beyond its already well-established role in producing new actin monomers. PMID:12482199

Coherent Raman Studies of Shocked Liquids

NASA Astrophysics Data System (ADS)

McGrane, Shawn; Brown, Kathryn; Dang, Nhan; Bolme, Cynthia; Moore, David

2013-06-01

Transient vibrational spectroscopies offer the potential to directly observe time dependent shock induced chemical reaction kinetics. We report recent experiments that couple a hybrid picosecond/femtosecond coherent anti-Stokes Raman spectroscopy (CARS) diagnostic with our tabletop ultrafast laser driven shock platform. Initial results on liquids shocked to 20 GPa suggest that sub-picosecond dephasing at high pressure and temperature may limit the application of this nonresonant background free version of CARS. Initial results using interferometric CARS to increase sensitivity and overcome these limitations will be presented.

Synthesis and testing of ZnO nanoparticles for photo-initiation: experimental observation of two different non-migration initiators for bulk polymerization.

PubMed

Schmitt, M

2015-06-07

The migration and transport of polymerization initiators are problematic for commercially used polymerization procedures. For example, UV printing of packaging generates products with potentially harmful components that come in contact with food. Enlarging the size of the initiator is the only way to prevent contamination, e.g., by gas phase transport. In this manuscript, the synthesis and advanced and full analyses of novel nanoparticle-based types of non-migration, fragmenting and non-fragmenting photo-initiators will be presented in detail. This study introduces non-fragmenting/"Norrish type II" and fragmenting/"Norrish type I" ZnO nanoparticle-based initiators and compares them with two commercial products, a "Norrish type I" initiator and a "Norrish type II" initiator. Therefore, inter alia, the recently developed analysis involves examining the solidification by UV-vis and the double bond content by Raman. Irradiation is performed using absolute and spectrally calibrated xenon flash lights. A novel procedure for absolute and spectral calibration of such light sources is also presented. The non-optimized "Norrish type II" particle-based initiator is already many times faster than benzophenone, which is a molecular initiator of the same non-fragmenting type. This experimentally observed difference in reactive particle-based systems without co-initiators is unexpected. Co-initiators are normally an additional molecular species, which leads to migration problems. The discovery of significant initiation potential resulting in a very well-dispersed organic-inorganic hybrid material suggests a new field of research opportunities at the interface of physical chemistry, polymer chemistry and engineering science, with enormous value for human health.

New Universal Rules of Eukaryotic Translation Initiation Fidelity

PubMed Central

Zur, Hadas; Tuller, Tamir

2013-01-01

The accepted model of eukaryotic translation initiation begins with the scanning of the transcript by the pre-initiation complex from the 5′end until an ATG codon with a specific nucleotide (nt) context surrounding it is recognized (Kozak rule). According to this model, ATG codons upstream to the beginning of the ORF should affect translation. We perform for the first time, a genome-wide statistical analysis, uncovering a new, more comprehensive and quantitative, set of initiation rules for improving the cost of translation and its efficiency. Analyzing dozens of eukaryotic genomes, we find that in all frames there is a universal trend of selection for low numbers of ATG codons; specifically, 16–27 codons upstream, but also 5–11 codons downstream of the START ATG, include less ATG codons than expected. We further suggest that there is selection for anti optimal ATG contexts in the vicinity of the START ATG. Thus, the efficiency and fidelity of translation initiation is encoded in the 5′UTR as required by the scanning model, but also at the beginning of the ORF. The observed nt patterns suggest that in all the analyzed organisms the pre-initiation complex often misses the START ATG of the ORF, and may start translation from an alternative initiation start-site. Thus, to prevent the translation of undesired proteins, there is selection for nucleotide sequences with low affinity to the pre-initiation complex near the beginning of the ORF. With the new suggested rules we were able to obtain a twice higher correlation with ribosomal density and protein levels in comparison to the Kozak rule alone (e.g. for protein levels r = 0.7 vs. r = 0.31; p<10−12). PMID:23874179

Nonequilibrium thermodynamics of the Markovian Mpemba effect and its inverse

PubMed Central

Raz, Oren

2017-01-01

Under certain conditions, it takes a shorter time to cool a hot system than to cool the same system initiated at a lower temperature. This phenomenon—the “Mpemba effect”—was first observed in water and has recently been reported in other systems. Whereas several detail-dependent explanations were suggested for some of these observations, no common underlying mechanism is known. Using the theoretical framework of nonequilibrium thermodynamics, we present a widely applicable mechanism for a similar effect, the Markovian Mpemba effect, derive a sufficient condition for its appearance, and demonstrate it explicitly in three paradigmatic systems: the Ising model, diffusion dynamics, and a three-state system. In addition, we predict an inverse Markovian Mpemba effect in heating: Under proper conditions, a cold system can heat up faster than the same system initiated at a higher temperature. We numerically demonstrate that this inverse effect is expected in a 1D antiferromagnet nearest-neighbors interacting Ising chain in the presence of an external magnetic field. Our results shed light on the mechanism behind anomalous heating and cooling and suggest that it should be possible to observe these in a variety of systems. PMID:28461467

High-speed nanoscale characterization of dewetting via dynamic transmission electron microscopy

NASA Astrophysics Data System (ADS)

Hihath, Sahar; Santala, Melissa K.; Campbell, Geoffrey; van Benthem, Klaus

2016-08-01

The dewetting of thin films can occur in either the solid or the liquid state for which different mass transport mechanisms are expected to control morphological changes. Traditionally, dewetting dynamics have been examined on time scales between several seconds to hours, and length scales ranging between nanometers and millimeters. The determination of mass transport mechanisms on the nanoscale, however, requires nanoscale spatial resolution and much shorter time scales. This study reports the high-speed observation of dewetting phenomena for kinetically constrained Ni thin films on crystalline SrTiO3 substrates. Movie-mode Dynamic Transmission Electron Microscopy (DTEM) was used for high-speed image acquisition during thin film dewetting at different temperatures. DTEM imaging confirmed that the initial stages of film agglomeration include edge retraction, hole formation, and growth. Finite element modeling was used to simulate temperature distributions within the DTEM samples after laser irradiation with different energies. For pulsed laser irradiation at 18 μJ, experimentally observed hole growth suggests that Marangoni flow dominates hole formation in the liquid nickel film. After irradiation with 13.8 μJ, however, the observations suggest that dewetting was initiated by nucleation of voids followed by hole growth through solid-state surface diffusion.

Shock initiation of nitromethane

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

Yoo, C.S.; Holmes, N.C.

1994-07-10

The shock initiation processes of nitromethane have been examined by using a fast time-resolved emission spectroscopy at a two-stage gas gun. A broad, but strong emission has been observed in a spectral range between 350 nm and 700 nm from the shocked nitromethane above 9 GPa. The temporal profile suggests that the shocked nitromethane detonates through three characteristic periods, namely an induction period, a shock initiation period, and a thermal explosion period. In this paper we will discuss the temporal and chemical characteristics of these periods and present the temperature of the shock-detonating nitromethane at pressures between 9 and 15more » GPa. [copyright]American Institute of Physics« less

Improved forecasts of winter weather extremes over midlatitudes with extra Arctic observations

NASA Astrophysics Data System (ADS)

Sato, Kazutoshi; Inoue, Jun; Yamazaki, Akira; Kim, Joo-Hong; Maturilli, Marion; Dethloff, Klaus; Hudson, Stephen R.; Granskog, Mats A.

2017-02-01

Recent cold winter extremes over Eurasia and North America have been considered to be a consequence of a warming Arctic. More accurate weather forecasts are required to reduce human and socioeconomic damages associated with severe winters. However, the sparse observing network over the Arctic brings errors in initializing a weather prediction model, which might impact accuracy of prediction results at midlatitudes. Here we show that additional Arctic radiosonde observations from the Norwegian young sea ICE expedition (N-ICE2015) drifting ice camps and existing land stations during winter improved forecast skill and reduced uncertainties of weather extremes at midlatitudes of the Northern Hemisphere. For two winter storms over East Asia and North America in February 2015, ensemble forecast experiments were performed with initial conditions taken from an ensemble atmospheric reanalysis in which the observation data were assimilated. The observations reduced errors in initial conditions in the upper troposphere over the Arctic region, yielding more precise prediction of the locations and strengths of upper troughs and surface synoptic disturbances. Errors and uncertainties of predicted upper troughs at midlatitudes would be brought with upper level high potential vorticity (PV) intruding southward from the observed Arctic region. This is because the PV contained a "signal" of the additional Arctic observations as it moved along an isentropic surface. This suggests that a coordinated sustainable Arctic observing network would be effective not only for regional weather services but also for reducing weather risks in locations distant from the Arctic.

Chancellor Water Colloids: Characterization and Radionuclide Associated Transport

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

Reimus, Paul William; Boukhalfa, Hakim

2014-09-26

Column transport experiments were conducted in which water from the Chancellor nuclear test cavity was transported through crushed volcanic tuff from Pahute Mesa. In one experiment, the cavity water was spiked with solute 137Cs, and in another it was spiked with 239/240Pu(IV) nanocolloids. A third column experiment was conducted with no radionuclide spike at all, although the 137Cs concentrations in the water were still high enough to quantify in the column effluent. The radionuclides strongly partitioned to natural colloids present in the water, which were characterized for size distribution, mass concentration, zeta potential/surface charge, critical coagulation concentration, and qualitative mineralogy.more » In the spiked water experiments, the unanalyzed portion of the high-concentration column effluent samples were combined and re-injected into the respective columns as a second pulse. This procedure was repeated again for a third injection. Measurable filtration of the colloids was observed after each initial injection of the Chancellor water into the columns, but the subsequent injections (spiked water experiments only) exhibited no apparent filtration, suggesting that the colloids that remained mobile after relatively short transport distances were more resistant to filtration than the initial population of colloids. It was also observed that while significant desorption of 137Cs from the colloids occurred after the first injection in both the spiked and unspiked waters, subsequent injections of the spiked water exhibited much less 137Cs desorption (much greater 137Cs colloid-associated transport). This result suggests that the 137Cs that remained associated with colloids during the first injection represented a fraction that was more strongly adsorbed to the mobile colloids than the initial 137Cs associated with the colloids. A greater amount of the 239/240Pu desorbed from the colloids during the second column injection compared to the first injection, but then desorption decreased significantly in the third injection. This result suggests that the Pu(IV) nanocolloids probably at least partially dissolved during and after the first injection, resulting in enhanced desorption from the colloids during the second injection, but by the third injection the Pu started following the same trend that was observed for 137Cs. The experiments suggest a transport scale dependence in which mobile colloids and colloid-associated radionuclides observed at downstream points along a flow path have a greater tendency to remain mobile along the flow path than colloids and radionuclides observed at upstream points. This type of scale dependence may help explain observations of colloid-facilitated Pu transport over distances of up to 2 km at Pahute Mesa.« less

POST-OUTBURST RADIO OBSERVATIONS OF THE HIGH MAGNETIC FIELD PULSAR PSR J1119-6127

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

Majid, Walid A.; Pearlman, Aaron B.; Dobreva, Tatyana

We have carried out high-frequency radio observations of the high magnetic field pulsar PSR J1119-6127 following its recent X-ray outburst. While initial observations showed no evidence of significant radio emission, subsequent observations detected pulsed emission across a large frequency band. In this Letter, we report on the initial disappearance of the pulsed emission and its prompt reactivation and dramatic evolution over several months of observation. The periodic pulse profile at S -band (2.3 GHz) after reactivation exhibits a multi-component emission structure, while the simultaneous X -band (8.4 GHz) profile shows a single emission peak. Single pulses were also detected atmore » S -band near the main emission peaks. We present measurements of the spectral index across a wide frequency bandwidth, which captures the underlying changes in the radio emission profile of the neutron star. The high-frequency radio detection, unusual emission profile, and observed variability suggest similarities with magnetars, which may independently link the high-energy outbursts to magnetar-like behavior.« less

A MODEL FOR POSTRADIATION STEM CELL KINETICS,

DTIC Science & Technology

In polycythemic rats observed for 17 days postradiation (300 R, 250 KVP X-rays) it was noted that stem cell release diminished to 8 percent of the...correlate these findings with a kinetic model of erythropoiesis. It was suggested that the initial depression in stem cell release might be due to cellular

Negotiating towards a Next Turn: Phonetic Resources for "Doing the Same"

ERIC Educational Resources Information Center

Sikveland, Rein Ove

2012-01-01

This paper investigates hearers' use of response tokens (back-channels), in maintaining and differentiating their actions. Initial observations suggest that hearers produce a sequence of phonetically similar responses to disengage from the current topic, and dissimilar responses to engage with the current topic. This is studied systematically by…

A comparison of freeway and parallel major arterial corridors : a study of safety patterns in the Denver metropolitan area.

DOT National Transportation Integrated Search

2015-11-01

Observations and initial examination of ADT and peak-hour volume data on Denver regional arterials suggests questions as : to if and why they are happening, and what the implications are on corridor travel and accident patterns? This proposed : resea...

Wavelength selection of rolling-grain ripples in the laboratory

NASA Astrophysics Data System (ADS)

Rousseaux, Germain; Stegner, Alexandre; Wesfreid, José Eduardo

2004-03-01

We have performed an experimental study, at very high resolution, of the wavelength selection and the evolution of rolling-grain ripples. A clear distinction is made between the flat sand bed instability and the ripple coarsening. The observation of the initial wavelength for the rolling-grain ripples is only possible close to the threshold for movement which imposes a constraint on the parameters. Moreover, we have proposed a law for the selection of the unstable wavelength under the latter constraint. Our results suggest that the initial wavelength depends on the amplitude of oscillation, the grain diameter, and the Stokes layer. Besides, during the coarsening, we observe no self-similarity of the ripple shape and for few cases a logarithmic growth of the wavelength.

Alzheimer's disease and other neurological disorders.

PubMed

Henderson, V W

2007-10-01

Menopausal status and estrogen-containing hormone therapy may influence several neurological disorders, including Alzheimer's disease, epilepsy, migraine headache, multiple sclerosis, Parkinson's disease, sleep disorders, and stroke. For most of these illnesses, evidence on hormone therapy is insufficient to guide practice decisions. For stroke, clinical trial evidence indicates that hormone therapy increases risk of cerebral infarction. For women with Alzheimer's disease, estrogen treatment trials have tended to be small and of short duration. Most suggest that estrogen started after the onset of dementia symptoms does not meaningfully improve cognition or slow disease progression. Hormone therapy initiated after age 64 increased all-cause dementia in the Women's Health Initiative Memory Study. Many observational studies, however, report protective associations between hormone use and Alzheimer risk. Apparent risk reduction may represent a bias toward hormone therapy, since hormones are more often prescribed to healthier women. However, when compared to the Women's Health Initiative Memory Study, estrogen exposures in many observational studies reflect hormone initiation at a younger age, closer to the time of menopause. One intriguing hypothesis is that hormone therapy initiated or used during an early critical window may reduce later Alzheimer incidence. Public health implications of this hypothesis are important, but current data are inadequate to decide the issue.

Initiation of Negative Streamers from Hydrometeors at Subbreakdown Field Conditions

NASA Astrophysics Data System (ADS)

Shi, F.; Liu, N.; Dwyer, J. R.; Tilles, J.

2017-12-01

Recent high-speed interferometer observations have indicated that the initiation of lightning may begin as compact intracloud discharges (CIDs) [Rison et al., Nat. Commun., 7, 10721, 2016], which are caused by a process termed fast positive breakdown. It is hypothesized that fast positive breakdown consists of a system of positive streamers [Rison et al., 2016]. A follow-up investigation by using the same interferometer has found that CIDs can also be caused by fast negative breakdown [Tilles et al., AE12A-03, AGU Fall Meeting, 2016]. If negative streamers are the underlying process driving fast negative breakdown, this suggests that negative streamers can be initiated and propagate through a significant distance of about one kilometer without detectable signals from positive streamers. However, initiation of negative streamers from isolated hydrometeors in subbreakdown fields has never been reproduced by modeling studies [Liu et al., Phys. Rev. Lett., 109, 025002, 2012; Sadighi et al., J. Geophys. Res. Atmos., 120, 3660, 2015; Shi et al., J. Geophys. Res. Atmos., 121, 7284, 2016]. In this talk, we will show that negative streamers can be successfully initiated from the tip of a cone-shape hydrometeor in an electric field well below conventional breakdown threshold field, suggesting that the shape of a hydrometeor plays an important role in streamer initiation. Formation of positive streamers may follow the initiation of negative streamers, and the characteristics of positive and negative streamers developing in the same subbreakdown field can be very different. For example, the peak field of the positive streamer head is almost two times larger than that of the negative head; the streamer channel density of the positive streamer is larger than that of the negative streamer; and the growth rate of the positive streamer is larger than that of the negative streamer. We will discuss the implications of our modeling results in the context of the observations of fast positive and negative breakdown.

Synthesis and testing of ZnO nanoparticles for photo-initiation: experimental observation of two different non-migration initiators for bulk polymerization

NASA Astrophysics Data System (ADS)

Schmitt, M.

2015-05-01

The migration and transport of polymerization initiators are problematic for commercially used polymerization procedures. For example, UV printing of packaging generates products with potentially harmful components that come in contact with food. Enlarging the size of the initiator is the only way to prevent contamination, e.g., by gas phase transport. In this manuscript, the synthesis and advanced and full analyses of novel nanoparticle-based types of non-migration, fragmenting and non-fragmenting photo-initiators will be presented in detail. This study introduces non-fragmenting/``Norrish type II'' and fragmenting/``Norrish type I'' ZnO nanoparticle-based initiators and compares them with two commercial products, a ``Norrish type I'' initiator and a ``Norrish type II'' initiator. Therefore, inter alia, the recently developed analysis involves examining the solidification by UV-vis and the double bond content by Raman. Irradiation is performed using absolute and spectrally calibrated xenon flash lights. A novel procedure for absolute and spectral calibration of such light sources is also presented. The non-optimized ``Norrish type II'' particle-based initiator is already many times faster than benzophenone, which is a molecular initiator of the same non-fragmenting type. This experimentally observed difference in reactive particle-based systems without co-initiators is unexpected. Co-initiators are normally an additional molecular species, which leads to migration problems. The discovery of significant initiation potential resulting in a very well-dispersed organic-inorganic hybrid material suggests a new field of research opportunities at the interface of physical chemistry, polymer chemistry and engineering science, with enormous value for human health.The migration and transport of polymerization initiators are problematic for commercially used polymerization procedures. For example, UV printing of packaging generates products with potentially harmful components that come in contact with food. Enlarging the size of the initiator is the only way to prevent contamination, e.g., by gas phase transport. In this manuscript, the synthesis and advanced and full analyses of novel nanoparticle-based types of non-migration, fragmenting and non-fragmenting photo-initiators will be presented in detail. This study introduces non-fragmenting/``Norrish type II'' and fragmenting/``Norrish type I'' ZnO nanoparticle-based initiators and compares them with two commercial products, a ``Norrish type I'' initiator and a ``Norrish type II'' initiator. Therefore, inter alia, the recently developed analysis involves examining the solidification by UV-vis and the double bond content by Raman. Irradiation is performed using absolute and spectrally calibrated xenon flash lights. A novel procedure for absolute and spectral calibration of such light sources is also presented. The non-optimized ``Norrish type II'' particle-based initiator is already many times faster than benzophenone, which is a molecular initiator of the same non-fragmenting type. This experimentally observed difference in reactive particle-based systems without co-initiators is unexpected. Co-initiators are normally an additional molecular species, which leads to migration problems. The discovery of significant initiation potential resulting in a very well-dispersed organic-inorganic hybrid material suggests a new field of research opportunities at the interface of physical chemistry, polymer chemistry and engineering science, with enormous value for human health. Electronic supplementary information (ESI) available: Multiple additional figures and images concerning the synthesis, characterization, data evaluation, TEMs and ESR spectra are available free of charge. See DOI: 10.1039/c5nr00850f

Intravesical Bacillus Calmette-Guérin therapy for murine bladder tumors: initiation of the response by fibronectin-mediated attachment of Bacillus Calmette-Guérin.

PubMed

Ratliff, T L; Palmer, J O; McGarr, J A; Brown, E J

1987-04-01

Intravesical Bacillus Calmette-Guérin (BCG) is considered to be one of the most effective treatments for superficial bladder cancer. Although the mechanisms by which BCG inhibits tumor growth are not known, previous studies have shown that systemic immunization to BCG and the local expression of the immune response in the bladder are associated with a favorable response to BCG therapy. We have investigated the conditions required for the initiation of an immunological response after the intravesical instillation of BCG. Initial histological studies showed that BCG attached to the bladder wall only in areas where the urothelium was damaged by electrocautery and suggested that attachment was associated with the fibrin clot. Quantitative studies verified the histological observations. Minimal BCG attachment (mean less than 10(2) colony forming units) was observed in normal bladders in contrast with a mean of 1.42 X 10(4) colony forming units/bladder in bladders damaged by electrocautery (10 separate experiments). BCG attachment to the bladder wall was durable since organisms were observed in bladders 48 h after instillation. To investigate the proteins to which BCG attached, we tested the binding of BCG to extracellular matrix and inflammatory proteins which comprise a significant portion of the fibrin clot. BCG bound in vitro to coverslips coated in vivo with extracellular matrix proteins but did not bind to control albumin-coated coverslips. BCG also bound to coverslips coated with purified plasma fibronectin but not to coverslips coated with other purified extracellular matrix proteins including laminin, fibrinogen, and type IV collagen. BCG attachment to coverslips coated with either extracellular matrix proteins or purified fibronectin was inhibited by antibodies specific for fibronectin. Moreover, BCG attachment to cauterized bladders in vivo was inhibited by antifibronectin antibodies. These results demonstrate that fibronectin mediates the attachment of BCG to surfaces and suggest that it is the primary component mediating attachment within the bladder. Moreover, the data suggest that the BCG-fibronectin interaction may be a requisite first step for the initiation of the antitumor activity in intravesical BCG for bladder cancer.

No Risk of Myocardial Infarction Associated With Initial Antiretroviral Treatment Containing Abacavir: Short and Long-Term Results from ACTG A5001/ALLRT

PubMed Central

Benson, Constance A.; Zheng, Yu; Koletar, Susan L.; Collier, Ann C.; Lok, Judith J.; Smurzynski, Marlene; Bosch, Ronald J.; Bastow, Barbara; Schouten, Jeffrey T.

2011-01-01

Background. Observational and retrospective clinical trial cohorts have reported conflicting results for the association of abacavir use with risk of myocardial infarction (MI), possibly related to issues that may bias estimation of treatment effects, such as time-varying confounders, informative dropout, and cohort loss due to competing events. Methods. We analyzed data from 5056 individuals initiating randomized antiretroviral treatment (ART) in AIDS Clinical Trials Group studies; 1704 started abacavir therapy. An intent-to-treat analysis adjusted for pretreatment covariates and weighting for informative censoring was used to estimate the hazard ratio (HR) of MIs after initiation of a regimen with or without abacavir. Results. Through 6 years after ART initiation, 36 MI events were observed in 17,404 person-years of follow-up. No evidence of an increased hazard of MI in subjects using abacavir versus no abacavir was seen (over a 1-year period: P = .50; HR, 0.7 [95% confidence interval {CI}, 0.2-2.4]); over a 6-year period: P = .24; HR, 0.6 [95% CI, 0.3-1.4]); these results were robust over as-treated and sensitivity analyses. Although the risk of MI decreased over time, there was no evidence to suggest a time-dependent abacavir effect. Classic cardiovascular disease (CVD) risk factors were the strongest predictors of MI. Conclusion. We find no evidence to suggest that initial ART containing abacavir increases MI risk over short-term and long-term periods in this population with relatively low MI risk. Traditional CVD risk factors should be the main focus in assessing CVD risk in individuals with human immunodeficiency virus infection. PMID:21427402

No risk of myocardial infarction associated with initial antiretroviral treatment containing abacavir: short and long-term results from ACTG A5001/ALLRT.

PubMed

Ribaudo, Heather J; Benson, Constance A; Zheng, Yu; Koletar, Susan L; Collier, Ann C; Lok, Judith J; Smurzynski, Marlene; Bosch, Ronald J; Bastow, Barbara; Schouten, Jeffrey T

2011-04-01

Observational and retrospective clinical trial cohorts have reported conflicting results for the association of abacavir use with risk of myocardial infarction (MI), possibly related to issues that may bias estimation of treatment effects, such as time-varying confounders, informative dropout, and cohort loss due to competing events. We analyzed data from 5056 individuals initiating randomized antiretroviral treatment (ART) in AIDS Clinical Trials Group studies; 1704 started abacavir therapy. An intent-to-treat analysis adjusted for pretreatment covariates and weighting for informative censoring was used to estimate the hazard ratio (HR) of MIs after initiation of a regimen with or without abacavir. Through 6 years after ART initiation, 36 MI events were observed in 17,404 person-years of follow-up. No evidence of an increased hazard of MI in subjects using abacavir versus no abacavir was seen (over a 1-year period: P=.50; HR, 0.7 [95% confidence interval {CI}, 0.2-2.4]); over a 6-year period: P=.24; HR, 0.6 [95% CI, 0.3-1.4]); these results were robust over as-treated and sensitivity analyses. Although the risk of MI decreased over time, there was no evidence to suggest a time-dependent abacavir effect. Classic cardiovascular disease (CVD) risk factors were the strongest predictors of MI. We find no evidence to suggest that initial ART containing abacavir increases MI risk over short-term and long-term periods in this population with relatively low MI risk. Traditional CVD risk factors should be the main focus in assessing CVD risk in individuals with human immunodeficiency virus infection. © The Author 2011. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved.

Precursor state of oxygen molecules on the Si(001) surface during the initial room-temperature adsorption

NASA Astrophysics Data System (ADS)

Hwang, Eunkyung; Chang, Yun Hee; Kim, Yong-Sung; Koo, Ja-Yong; Kim, Hanchul

2012-10-01

The initial adsorption of oxygen molecules on Si(001) is investigated at room temperature. The scanning tunneling microscopy images reveal a unique bright O2-induced feature. The very initial sticking coefficient of O2 below 0.04 Langmuir is measured to be ˜0.16. Upon thermal annealing at 250-600 °C, the bright O2-induced feature is destroyed, and the Si(001) surface is covered with dark depressions that seem to be oxidized structures with -Si-O-Si- bonds. This suggests that the observed bright O2-induced feature is an intermediate precursor state that may be either a silanone species or a molecular adsorption structure.

Massive, wide binaries as tracers of massive star formation

NASA Astrophysics Data System (ADS)

Griffiths, Daniel W.; Goodwin, Simon P.; Caballero-Nieves, Saida M.

2018-05-01

Massive stars can be found in wide (hundreds to thousands au) binaries with other massive stars. We use N-body simulations to show that any bound cluster should always have approximately one massive wide binary: one will probably form if none are present initially, and probably only one will survive if more than one is present initially. Therefore, any region that contains many massive wide binaries must have been composed of many individual subregions. Observations of Cyg OB2 show that the massive wide binary fraction is at least a half (38/74), which suggests that Cyg OB2 had at least 30 distinct massive star formation sites. This is further evidence that Cyg OB2 has always been a large, low-density association. That Cyg OB2 has a normal high-mass initial mass function (IMF) for its total mass suggests that however massive stars form, they `randomly sample' the IMF (as the massive stars did not `know' about each other).

Fatigue-Induced Damage in Zr-Based Bulk Metallic Glasses

PubMed Central

Chuang, Chih-Pin; Yuan, Tao; Dmowski, Wojciech; Wang, Gong-Yao; Freels, Matt; Liaw, Peter K.; Li, Ran; Zhang, Tao

2013-01-01

In the present work, we investigate the effect of “fatigue” on the fatigue behavior and atomic structure of Zr-based BMGs. Fatigue experiments on the failed-by-fatigue samples indicate that the remnants generally have similar or longer fatigue life than the as-cast samples. Meanwhile, the pair-distribution-function (PDF) analysis of the as-cast and post-fatigue samples showed very small changes of local atomic structures. These observations suggest that the fatigue life of the 6-mm in-diameter Zr-based BMG is dominated by the number of pre-existing crack-initiation sites in the sample. Once the crack initiates in the specimen, the fatigue-induced damage is accumulated locally on these initiated sites, while the rest of the region deforms elastically. The results suggest that the fatigue failure of BMGs under compression-compression fatigue experiments is a defect-controlled process. The present work indicates the significance of the improved fatigue resistance with decreasing the sample size. PMID:23999496

The initiation of segmented buoyancy-driven melting during continental breakup

PubMed Central

Gallacher, Ryan J.; Keir, Derek; Harmon, Nicholas; Stuart, Graham; Leroy, Sylvie; Hammond, James O. S.; Kendall, J-Michael; Ayele, Atalay; Goitom, Berhe; Ogubazghi, Ghebrebrhan; Ahmed, Abdulhakim

2016-01-01

Melting of the mantle during continental breakup leads to magmatic intrusion and volcanism, yet our understanding of the location and dominant mechanisms of melt generation in rifting environments is impeded by a paucity of direct observations of mantle melting. It is unclear when during the rifting process the segmented nature of magma supply typical of seafloor spreading initiates. Here, we use Rayleigh-wave tomography to construct a high-resolution absolute three-dimensional shear-wave velocity model of the upper 250 km beneath the Afar triple junction, imaging the mantle response during progressive continental breakup. Our model suggests melt production is highest and melting depths deepest early during continental breakup. Elevated melt production during continental rifting is likely due to localized thinning and melt focusing when the rift is narrow. In addition, we interpret segmented zones of melt supply beneath the rift, suggesting that buoyancy-driven active upwelling of the mantle initiates early during continental rifting. PMID:27752044

Gender Differences in Barriers to Physical Activity among College Students Reporting Varying Levels of Regular Physical Activity

ERIC Educational Resources Information Center

Munford, Shawn N.

2011-01-01

Researchers have studied the primary determinants of physical activity in an effort to enhance health promotion initiatives nationwide. These physical activity determinants have been observed to differ among various segments of the population, suggesting a further examination of physical activity barriers among differing populations. Little…

Observation and Description: An Alternative Methodology for the Investigation of Human Phenomena.

ERIC Educational Resources Information Center

Carini, Patricia F.

This monograph is one of a continuing series initiated to provide materials for teachers, parents, school administrators, and governmental decision-makers that might encourage reexamination of a range of evaluation issues and perspectives about schools and schooling. This monograph suggests a radical departure from the approaches to educational…

Understanding Art: Preparing Generalist School Teachers to Teach Art with Artworks

ERIC Educational Resources Information Center

Pavlou, Victoria

2015-01-01

This article focuses on ways of building preservice primary teachers' confidence in teaching art with artworks and, in particular, on how to develop their pedagogical content knowing. It is suggested that through opportunities offered for engaging in observational and reflective practices with artworks an initial groundwork is set that can…

Stress-induced sensitization: the hypothalamic-pituitary-adrenal axis and beyond.

PubMed

Belda, Xavier; Fuentes, Silvia; Daviu, Nuria; Nadal, Roser; Armario, Antonio

2015-01-01

Exposure to certain acute and chronic stressors results in an immediate behavioral and physiological response to the situation followed by a period of days when cross-sensitization to further novel stressors is observed. Cross-sensitization affects to different behavioral and physiological systems, more particularly to the hypothalamus-pituitary-adrenal (HPA) axis. It appears that the nature of the initial (triggering) stressor plays a major role, HPA cross-sensitization being more widely observed with systemic or high-intensity emotional stressors. Less important appears to be the nature of the novel (challenging) stressor, although HPA cross-sensitization is better observed with short duration (5-15 min) challenging stressors. In some studies with acute immune stressors, HPA sensitization appears to develop over time (incubation), but most results indicate a strong initial sensitization that progressively declines over the days. Sensitization can affect other physiological system (i.e. plasma catecholamines, brain monoamines), but it is not a general phenomenon. When studied concurrently, behavioral sensitization appears to persist longer than that of the HPA axis, a finding of interest regarding long-term consequences of traumatic stress. In many cases, behavioral and physiological consequences of prior stress can only be observed following imposition of a new stressor, suggesting long-term latent effects of the initial exposure.

Temporal Sequence of Cell Wall Disassembly in Rapidly Ripening Melon Fruit1

PubMed Central

Rose, Jocelyn K.C.; Hadfield, Kristen A.; Labavitch, John M.; Bennett, Alan B.

1998-01-01

The Charentais variety of melon (Cucumis melo cv Reticulatus F1 Alpha) was observed to undergo very rapid ripening, with the transition from the preripe to overripe stage occurring within 24 to 48 h. During this time, the flesh first softened and then exhibited substantial disintegration, suggesting that Charentais may represent a useful model system to examine the temporal sequence of changes in cell wall composition that typically take place in softening fruit. The total amount of pectin in the cell wall showed little reduction during ripening but its solubility changed substantially. Initial changes in pectin solubility coincided with a loss of galactose from tightly bound pectins, but preceded the expression of polygalacturonase (PG) mRNAs, suggesting early, PG-independent modification of pectin structure. Depolymerization of polyuronides occurred predominantly in the later ripening stages, and after the appearance of PG mRNAs, suggesting the existence of PG-dependent pectin degradation in later stages. Depolymerization of hemicelluloses was observed throughout ripening, and degradation of a tightly bound xyloglucan fraction was detected at the early onset of softening. Thus, metabolism of xyloglucan that may be closely associated with cellulose microfibrils may contribute to the initial stages of fruit softening. A model is presented of the temporal sequence of cell wall changes during cell wall disassembly in ripening Charentais melon. PMID:9625688

Economic gains stimulate negative evaluations of corporate sustainability initiatives

NASA Astrophysics Data System (ADS)

Makov, Tamar; Newman, George E.

2016-09-01

In recent years, many organizations have sought to align their financial goals with environmental ones by identifying strategies that maximize profits while minimizing environmental impacts. Examples of this `win-win' approach can be found across a wide range of industries, from encouraging the reuse of hotel towels, to the construction of energy efficient buildings, to the large-scale initiatives of multi-national corporations. Although win-win strategies are generally thought to reflect positively on the organizations that employ them, here we find that people tend to respond negatively to the notion of profiting from environmental initiatives. In fact, observers may evaluate environmental win-wins less favourably than profit-seeking strategies that have no environmental benefits. The present studies suggest that how those initiatives are communicated to the general public may be of central importance. Therefore, organizations would benefit from carefully crafting the discourse around their win-win initiatives to ensure that they avoid this type of backlash.

Changes in oral ethanol self-administration patterns resulting from ethanol concentration manipulations.

PubMed

Slawecki, C J; Samson, H H

1997-09-01

A variety of initiation procedures have been used to develop oral ethanol consumption. Using the sucrose-substitution procedure, oral self-administration of ethanol-water solutions with ethanol concentrations as high as 40% can be initiated in food- and fluid-sated rats. An important question for these models is the relationship between ethanol concentration and self-administration patterns after initiation. This study examined the differential patterns of ethanol self-administration maintained by a range of ethanol solutions (10 to 30%) over a 5-week period, compared with rats maintained on 10% ethanol for 5 weeks. In 43 male Long Evans rats, the sucrose-substitution procedure was used to initiate responding maintained by 10% ethanol on a Fixed Ratio 4 schedule of reinforcement. The ethanol concentration presented was then increased to 30% in stepwise fashion and then returned to 10% [Ethanol Concentration Manipulation (ECM) group, n = 32], or 10% ethanol was maintained as the reinforcer for 5 weeks [Control (Con) group, n = 11]. Significant increases in ethanol intake and decreases in responding were associated with increased ethanol concentration. Although no overall differences in total session responding were observed in either group between week 1 and week 5 (10E vs. 10E), examination of changes in initial low responders of the ECM group revealed significant increases in responding that were not observed in the initial low responders of the Con group. Significant increases in momentary response rates were observed on both the ECM and Con groups, independent of the ethanol concentration presented. Increases in response rate in the ECM group were the result of increases in initial low rate and high rate responders; however, the increased response rates in the Con group were the result of increases only in the initial low rate responders. These data suggest that the ECM procedure can aid in the initiation of ethanol self-administration and may be particularly useful in rats of heterogeneous stock.

High-speed nanoscale characterization of dewetting via dynamic transmission electron microscopy

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

Hihath, Sahar; Department of Physics, University of California, Davis, 1 Shields Ave., Davis, California 95616; Santala, Melissa K.

The dewetting of thin films can occur in either the solid or the liquid state for which different mass transport mechanisms are expected to control morphological changes. Traditionally, dewetting dynamics have been examined on time scales between several seconds to hours, and length scales ranging between nanometers and millimeters. The determination of mass transport mechanisms on the nanoscale, however, requires nanoscale spatial resolution and much shorter time scales. This study reports the high-speed observation of dewetting phenomena for kinetically constrained Ni thin films on crystalline SrTiO{sub 3} substrates. Movie-mode Dynamic Transmission Electron Microscopy (DTEM) was used for high-speed image acquisitionmore » during thin film dewetting at different temperatures. DTEM imaging confirmed that the initial stages of film agglomeration include edge retraction, hole formation, and growth. Finite element modeling was used to simulate temperature distributions within the DTEM samples after laser irradiation with different energies. For pulsed laser irradiation at 18 μJ, experimentally observed hole growth suggests that Marangoni flow dominates hole formation in the liquid nickel film. After irradiation with 13.8 μJ, however, the observations suggest that dewetting was initiated by nucleation of voids followed by hole growth through solid-state surface diffusion.« less

Reservoir model for Hillsboro gas storage field management

USGS Publications Warehouse

Udegbunam, Emmanuel O.; Kemppainen, Curt; Morgan, Jim; ,

1995-01-01

A 3-dimensional reservoir model is used to understand the behavior of the Hillsboro Gas Storage Field and to investigate the field's performance under various future development. Twenty-two years of the gas storage reservoir history, comprising the initial gas bubble development and seasonal gas injection and production cycles, are examined with a full-field, gas water, reservoir simulation model. The results suggest that the gas-water front is already in the vicinity of the west observation well that increasing the field's total gas-in-place volume would cause gas to migrate beyond the east, north and west observation well. They also suggest that storage enlargement through gas injection into the lower layers may not prevent gas migration. Moreover, the results suggest that the addition of strategically-located new wells would boost the simulated gas deliverabilities.

Timing of dialysis initiation in transplant-naive and failed transplant patients

PubMed Central

Molnar, Miklos Z.; Ojo, Akinlolu O.; Bunnapradist, Suphamai; Kovesdy, Csaba P.; Kalantar-Zadeh, Kamyar

2017-01-01

Over the past two decades, most guidelines have advocated early dialysis initiation on the basis of studies showing improved survival in patients starting dialysis early. These recommendations led to an increase in the proportion of patients initiating dialysis with an estimated glomerular filtration rate (eGFR) >10 ml/min/1.73 m2, from 20% in 1996 to 52% in 2008. During this period, patients starting dialysis with an eGFR ≥15 ml/min/1.73 m2 increased from 4% to 17%. However, recent studies have failed to substantiate a benefit of early dialysis initiation and some data have suggested worse outcomes in patients starting dialysis with a higher eGFR. Several reasons for this seemingly paradoxical observation have been suggested, including the fact that patients requiring early dialysis are likely to have more severe symptoms and comorbidities, leading to confounding by indication, as well as biological mechanisms that causally relate early dialysis therapy to adverse outcomes. Dialysis reinitiation in patients with a failing renal allograft encounters similar problems. However, unique factors associated with a failed allograft means that the optimal timing of dialysis initiation in failed transplant patients might differ from that in transplant-naive patients. In this Review, we will discuss studies of dialysis initiation and compare risks and benefits of early versus late dialysis therapy. PMID:22371250

Probability of brittle failure

NASA Technical Reports Server (NTRS)

Kim, A.; Bosnyak, C. P.; Chudnovsky, A.

1991-01-01

A methodology was developed for collecting statistically representative data for crack initiation and arrest from small number of test specimens. An epoxy (based on bisphenol A diglycidyl ether and polyglycol extended diglycyl ether and cured with diethylene triamine) is selected as a model material. A compact tension specimen with displacement controlled loading is used to observe multiple crack initiation and arrests. The energy release rate at crack initiation is significantly higher than that at a crack arrest, as has been observed elsewhere. The difference between these energy release rates is found to depend on specimen size (scale effect), and is quantitatively related to the fracture surface morphology. The scale effect, similar to that in statistical strength theory, is usually attributed to the statistics of defects which control the fracture process. Triangular shaped ripples (deltoids) are formed on the fracture surface during the slow subcritical crack growth, prior to the smooth mirror-like surface characteristic of fast cracks. The deltoids are complementary on the two crack faces which excludes any inelastic deformation from consideration. Presence of defects is also suggested by the observed scale effect. However, there are no defects at the deltoid apexes detectable down to the 0.1 micron level.

Reliability and relationship of the fear-avoidance beliefs questionnaire with the shoulder pain and disability index and numeric pain rating scale in patients with shoulder pain.

PubMed

Riley, Sean P; Tafuto, Vincent; Cote, Mark; Brismée, Jean-Michel; Wright, Alexis; Cook, Chad

2018-03-20

The purpose of this study was to determine: 1) the test-retest reliability of Fear-Avoidance Beliefs Questionnaire (FABQ) Work (FABQW) subscale, FABQ Physical Activity (FABQPA) subscale, Shoulder Pain and Disability Index (SPADI) Pain subscale, SPADI Disability subscale, and Numeric Pain Rating scale (NPRS); and 2) the relationship between the FABQPA, FABQW, SPADI pain, SPADI disability, and NPRS after 4 weeks of pragmatically applied physical therapy (PT) in patients with shoulder pain. Prospective, single-group observational design. Data were collected at initial evaluation, the first follow-up visit prior to the initiation of treatment, and after 4 weeks of treatment. Statistically significant Intraclass Correlation Coefficient (ICC 2,1 ) values were reported for the FABQPA, FABQW, SPADI Pain, SPADI Disability, and NPRS. A statistically significant moderate relationship between the FABQPA subscale, SPADI subscale, and NPRS could not be established prior to and after 4 weeks of pragmatically applied PT. Statistically significant differences were observed between the initial evaluation and four-week follow-up for the FABQPA, SPADI Pain, SPADI Disability, and NPRS (p < 0.01). Since a meaningful relationship between the FABQ, SPADI, and NPRS did not exist, it suggests that the FABQPA may be measuring a metric other than pain. This study suggests that the FABQW may not be sensitive to change over time.

Effects of intravenous dimethyl sulfoxide on ischemia evolution in a rat permanent occlusion model

PubMed Central

Bardutzky, Juergen; Meng, Xianjun; Bouley, James; Duong, Timothy Q; Ratan, Rajiv; Fisher, Marc

2010-01-01

Dimethyl sulfoxide (DMSO) has a variety of biological actions that suggest efficacy as a neuroprotectant. We (1) tested the neuroprotective potential of DMSO at different time windows on infarct size using 2,3,5-triphenyltetrazolium staining and (2) investigated the effects of DMSO on ischemia evolution using quantitative diffusion and perfusion imaging in a permanent middle cerebral artery occlusion (MCAO) model in rats. In experiment 1, DMSO treatment (1.5 g/kg intravenously over 3 h) reduced infarct volume 24 h after MCAO by 65% (P<0.00001) when initiated 20 h before MCAO, by 44% (P=0.0006) when initiated 1 h after MCAO, and by 17% (P=0.11) when started 2 h after MCAO. Significant infarct reduction was also observed after a 3-day survival in animals treated 1 h after MCAO (P=0.005). In experiment 2, treatment was initiated 1 h after MCAO and maps for cerebral blood flow (CBF) and apparent diffusion coefficient (ADC) were acquired before treatment and then every 30 mins up to 4 h. Cerebral blood flow characteristics and CBF-derived lesion volumes did not differ between treated and untreated animals, whereas the ADC-derived lesion volume essentially stopped progressing during DMSO treatment, resulting in a persistent diffusion/perfusion mismatch. This effect was mainly observed in the cortex. Our data suggest that DMSO represents an interesting candidate for acute stroke treatment. PMID:15744247

Collapse of the West Antarctic Ice Sheet after local destabilization of the Amundsen Basin

PubMed Central

Feldmann, Johannes; Levermann, Anders

2015-01-01

The future evolution of the Antarctic Ice Sheet represents the largest uncertainty in sea-level projections of this and upcoming centuries. Recently, satellite observations and high-resolution simulations have suggested the initiation of an ice-sheet instability in the Amundsen Sea sector of West Antarctica, caused by the last decades’ enhanced basal ice-shelf melting. Whether this localized destabilization will yield a full discharge of marine ice from West Antarctica, associated with a global sea-level rise of more than 3 m, or whether the ice loss is limited by ice dynamics and topographic features, is unclear. Here we show that in the Parallel Ice Sheet Model, a local destabilization causes a complete disintegration of the marine ice in West Antarctica. In our simulations, at 5-km horizontal resolution, the region disequilibrates after 60 y of currently observed melt rates. Thereafter, the marine ice-sheet instability fully unfolds and is not halted by topographic features. In fact, the ice loss in Amundsen Sea sector shifts the catchment's ice divide toward the Filchner–Ronne and Ross ice shelves, which initiates grounding-line retreat there. Our simulations suggest that if a destabilization of Amundsen Sea sector has indeed been initiated, Antarctica will irrevocably contribute at least 3 m to global sea-level rise during the coming centuries to millennia. PMID:26578762

Polymer brush covalently attached to OH-functionalized mica surface via surface-initiated ATRP: control of grafting density and polymer chain length.

PubMed

Lego, Béatrice; François, Marion; Skene, W G; Giasson, Suzanne

2009-05-05

The controlled grafting density of poly(tert-butyl acrylate) was studied on OH-activated mica substrates via surface-initiated atom-transfer radical polymerization (ATRP). By properly adjusting parameters such as the immobilization reaction time and the concentration of an ATRP initiator, a wide range of initiator surface coverages and hence polymer densities on mica were possible. The covalently immobilized initiator successfully promoted the polymerization of tert-butyl acrylate on mica surfaces. The resulting polymer layer thickness was measured by AFM using a step-height method. Linear relationships of the polymer thickness with respect to the molecular weight of the free polymer and with respect to the monomer conversion were observed, suggesting that ATRP is well controlled and relatively densely end-grafted layers were obtained. The polymer grafting density controlled by adjusting the initiator surface coverage was confirmed by the polymer layer swelling capacity and film thickness measurements.

Initial contact guidance during cell spreading is contractility-independent.

PubMed

Sales, Adrià; Holle, Andrew W; Kemkemer, Ralf

2017-08-02

A wide variety of cell types exhibit substrate topography-based behavior, also known as contact guidance. However, the precise cellular mechanisms underlying this process are still unknown. In this study, we investigated contact guidance by studying the reaction of human endothelial cells (ECs) to well-defined microgroove topographies, both during and after initial cell spreading. As the cytoskeleton plays a major role in cellular adaptation to topographical features, two methods were used to perturb cytoskeletal structures. Inhibition of actomyosin contractility with the chemical inhibitor blebbistatatin demonstrated that initial contact guidance events are independent of traction force generation. However, cell alignment to the grooved substrate was altered at later time points, suggesting an initial 'passive' phase of contact guidance, followed by a contractility-dependent 'active' phase that relies on mechanosensitive feedback. The actin cytoskeleton was also perturbed in an indirect manner by culturing cells upside down, resulting in decreased levels of contact guidance and suggesting that a possible loss of contact between the actin cytoskeleton and the substrate could lead to cytoskeleton impairment. The process of contact guidance at the microscale was found to be primarily lamellipodia driven, as no bias in filopodia extension was observed on micron-scale grooves.

Effect of observation on lower limb prosthesis gait biomechanics: Preliminary results.

PubMed

Malchow, Connor; Fiedler, Goeran

2016-12-01

The Hawthorne effect, a subcategory of reactivity, causes human behavior to change when under observation. Such an effect may apply to gait variation of persons with prosthetics or orthotics devices. This study investigated whether the presence of observers directly affects the gait pattern of users of lower limb prostheses. Within-subject intervention study. Primary outcome measures were gait parameters of initial double support time and upper body lateral tilt angle, which were collected with a mobile sensor attached to the subjects' back. To make subjects feel unwatched, a certain amount of deception was necessary, and two different conditions were created and statistically compared against each other: one in which the subjects were initially unaware of the attention of observers and another one in which the same subjects were aware of a group of observers. Data from two subjects using trans-femoral prosthesis are reported. Findings included a change in step initial double support percentage by up to 14.2% (p = 0.019). Considerable changes were also noted in secondary outcome measures including speed, stride length, and stride symmetry. A reactivity effect of observation exists in prosthetics gait analysis. More comprehensive studies may be motivated by these preliminary findings. Results of this study suggest that users of lower limb prostheses walk differently when their gait is being assessed (e.g. in the prosthetist's office) than in situations without observers. This may in part explain the clinical experience that modifications of prosthetic fit or alignment provide only short-term betterment. © The International Society for Prosthetics and Orthotics 2015.

Metformin selectively affects human glioblastoma tumor-initiating cell viability

PubMed Central

Würth, Roberto; Pattarozzi, Alessandra; Gatti, Monica; Bajetto, Adirana; Corsaro, Alessandro; Parodi, Alessia; Sirito, Rodolfo; Massollo, Michela; Marini, Cecilia; Zona, Gianluigi; Fenoglio, Daniela; Sambuceti, Gianmario; Filaci, Gilberto; Daga, Antonio; Barbieri, Federica; Florio, Tullio

2013-01-01

Cancer stem cell theory postulates that a small population of tumor-initiating cells is responsible for the development, progression and recurrence of several malignancies, including glioblastoma. In this perspective, tumor-initiating cells represent the most relevant target to obtain effective cancer treatment. Metformin, a first-line drug for type II diabetes, was reported to possess anticancer properties affecting the survival of cancer stem cells in breast cancer models. We report that metformin treatment reduced the proliferation rate of tumor-initiating cell-enriched cultures isolated from four human glioblastomas. Metformin also impairs tumor-initiating cell spherogenesis, indicating a direct effect on self-renewal mechanisms. Interestingly, analyzing by FACS the antiproliferative effects of metformin on CD133-expressing subpopulation, a component of glioblastoma cancer stem cells, a higher reduction of proliferation was observed as compared with CD133-negative cells, suggesting a certain degree of cancer stem cell selectivity in its effects. In fact, glioblastoma cell differentiation strongly reduced sensitivity to metformin treatment. Metformin effects in tumor-initiating cell-enriched cultures were associated with a powerful inhibition of Akt-dependent cell survival pathway, while this pathway was not affected in differentiated cells. The specificity of metformin antiproliferative effects toward glioblastoma tumor-initiating cells was confirmed by the lack of significant inhibition of normal human stem cells (umbilical cord-derived mesenchymal stem cells) in vitro proliferation after metformin exposure. Altogether, these data clearly suggest that metformin exerts antiproliferative activity on glioblastoma cells, showing a higher specificity toward tumor-initiating cells, and that the inhibition of Akt pathway may represent a possible intracellular target of this effect. PMID:23255107

Parents' Positive Role in Students' Learning Process at Ishik University Preparatory School

ERIC Educational Resources Information Center

Tosun, Mustafa

2015-01-01

The reason that motivated me to initiate this writing is to emphasize the deficiency in the motivation and unwillingness of university youth cause of the parents approach toward the education at preparatory school. Moreover, my aim is to declare realistic suggestions about the issue with the help of observations that have been gained during the…

On the Short Horizon of Spontaneous Iterative Reasoning in Logical Puzzles and Games

ERIC Educational Resources Information Center

Mazzocco, Ketti; Cherubini, Anna Maria; Cherubini, Paolo

2013-01-01

A reasoning strategy is iterative when the initial conclusion suggested by a set of premises is integrated into that set of premises in order to yield additional conclusions. Previous experimental studies on game theory-based strategic games (such as the beauty contest game) observed difficulty in reasoning iteratively, which has been partly…

Reconsidering the Framework. Learning in Science Project. Working Paper No. 14.

ERIC Educational Resources Information Center

Osborne, Roger; And Others

The first working paper of the Learning in Science Project, "An Initial Framework," outlined what was then seen as the major aims of the project and suggested how these aims might be achieved by three phases of research: exploratory (to observe teaching/learning in Form 1 to 4 science classrooms and to identify difficulties perceived by…

High-Order Shock-Capturing Methods for Modeling Dynamics of the Solar Atmosphere

NASA Technical Reports Server (NTRS)

Bryson, Steve; Kosovichev, Alexander; Levy, Doron

2004-01-01

We use one-dimensional high-order central shock capturing numerical methods to study the response of various model solar atmospheres to forcing at the solar surface. The dynamics of the atmosphere is modeled with the Euler equations in a variable-sized flux tube in the presence of gravity. We study dynamics of the atmosphere suggestive of spicule formation and coronal oscillations. These studies are performed on observationally-derived model atmospheres above the quiet sun and above sunspots. To perform these simulations, we provide a new extension of existing second- and third- order shock-capturing methods to irregular grids. We also solve the problem of numerically maintaining initial hydrostatic balance via the introduction of new variables in the model equations and a careful initialization mechanism. We find several striking results: all model atmospheres respond to a single impulsive perturbation with several strong shock waves consistent with the rebound-shock model. These shock waves lift material and the transition region well into the initial corona, and the sensitivity of this lift to the initial impulse depends non-linearly on the details of the atmosphere model. We also reproduce an observed 3-minute coronal oscillation above sunspots compared to 5-minute oscillations above the quiet sun.

Initial eye movements during face identification are optimal and similar across cultures

PubMed Central

Or, Charles C.-F.; Peterson, Matthew F.; Eckstein, Miguel P.

2015-01-01

Culture influences not only human high-level cognitive processes but also low-level perceptual operations. Some perceptual operations, such as initial eye movements to faces, are critical for extraction of information supporting evolutionarily important tasks such as face identification. The extent of cultural effects on these crucial perceptual processes is unknown. Here, we report that the first gaze location for face identification was similar across East Asian and Western Caucasian cultural groups: Both fixated a featureless point between the eyes and the nose, with smaller between-group than within-group differences and with a small horizontal difference across cultures (8% of the interocular distance). We also show that individuals of both cultural groups initially fixated at a slightly higher point on Asian faces than on Caucasian faces. The initial fixations were found to be both fundamental in acquiring the majority of information for face identification and optimal, as accuracy deteriorated when observers held their gaze away from their preferred fixations. An ideal observer that integrated facial information with the human visual system's varying spatial resolution across the visual field showed a similar information distribution across faces of both races and predicted initial human fixations. The model consistently replicated the small vertical difference between human fixations to Asian and Caucasian faces but did not predict the small horizontal leftward bias of Caucasian observers. Together, the results suggest that initial eye movements during face identification may be driven by brain mechanisms aimed at maximizing accuracy, and less influenced by culture. The findings increase our understanding of the interplay between the brain's aims to optimally accomplish basic perceptual functions and to respond to sociocultural influences. PMID:26382003

Oscillon in Einstein-scalar system with double well potential and its properties.

NASA Astrophysics Data System (ADS)

Ikeda, Taishi; Yoo, Chul-Moon; Cardoso, Vitor

2018-01-01

The dynamical evolution of self-interacting scalar field has many nontrivial behaviors, which tell us many lessons in a nonlinear dynamics. On Minkowski spacetime, the scalar field with double well potential has localized, non-singular, time-dependent, long-lived solutions, which are called oscillons. The lifetime of the oscillon depends on the initial conditions. Furthermore, when the initial parameter is fine-tuned, oscillons can be infinitely, and type I critical behavior is observed. Here, we investigate the Einstein-scalar system with double well potential. We show that oscillons exist in this system, and discuss the behavior when the initial parameter is fine-tuned. Our results suggests that a new type of critical behavior appears in this theory.

Alliance ruptures and rupture resolution in cognitive-behavior therapy: a preliminary task analysis.

PubMed

Aspland, Helen; Llewelyn, Susan; Hardy, Gillian E; Barkham, Michael; Stiles, William

2008-11-01

An initial ideal, rational model of alliance rupture and rupture resolution provided by cognitive-behavioral therapy (CBT) experts was assessed and compared with empirical observations of ruptures and their resolution in two cases of successful CBT. The initial rational model emphasized nondefensive acknowledgment and exploration of the rupture. Results indicated differences between what therapists think they should do to resolve ruptures and what they actually do and suggested that the rational model should be expanded to emphasize client validation and empowerment. Therapists' ability to attend to ruptures emerged as an important clinical skill.

Intra- and inter-observer reliability of quantitative analysis of the infra-patellar fat pad and comparison between fat- and non-fat-suppressed imaging--Data from the osteoarthritis initiative.

PubMed

Steidle-Kloc, E; Wirth, W; Ruhdorfer, A; Dannhauer, T; Eckstein, F

2016-03-01

The infra-patellar fat pad (IPFP), as intra-articular adipose tissue represents a potential source of pro-inflammatory cytokines and its size has been suggested to be associated with osteoarthritis (OA) of the knee. This study examines inter- and intra-observer reliability of fat-suppressed (fs) and non-fat-suppressed (nfs) MR imaging for determination of IPFP morphological measurements as novel biomarkers. The IPFP of nine right knees of healthy Osteoarthritis Initiative participants was segmented by five readers, using fs and nfs baseline sagittal MRIs. The intra-observer reliability was determined from baseline and 1-year follow-up images. All segmentations were quality controlled (QC) by an expert reader. Reliability was expressed as root mean square coefficient of variation (RMS CV%). After QC, the inter-observer reliability for fs (nfs) imaging was 2.0% (1.1%) for IPFP volume, 2.1%/2.5% (1.6%/1.8%) for anterior/posterior surface areas, 1.8% (1.8%) for depth, and 2.1% (2.4%) for maximum sagittal area. The intra-observer reliability was 3.1% (5.0%) for volume, 2.3%/2.8% (2.5%/2.9%) for anterior/posterior surfaces, 1.9% (3.5%) for depth, and 3.3% (4.5%) for maximum sagittal area. IPFP volume from nfs images was systematically greater (+7.3%) than from fs images, but highly correlated (r=0.98). The results suggest that quantitative measurements of IPFP morphology can be performed with satisfactory reliability when expert QC is implemented. The IPFP is more clearly depicted in nfs images, and there is a small systematic off-set versus analysis from fs images. However, the high linear relationship between fs and nfs imaging suggests that fs images can be used to analyze IPFP morphology, when nfs images are not available. Copyright © 2015 Elsevier GmbH. All rights reserved.

Intra- and inter-observer reliability of quantitative analysis of the infra-patellar fat pad and comparison between fat- and non-fat-suppressed imaging—Data from the osteoarthritis initiative

PubMed Central

Steidle-Kloc, E.; Wirth, W.; Ruhdorfer, A.; Dannhauer, T.; Eckstein, F.

2015-01-01

The infra-patellar fat pad (IPFP), as intra-articular adipose tissue represents a potential source of pro-inflammatory cytokines and its size has been suggested to be associated with osteoarthritis (OA) of the knee. This study examines inter- and intra-observer reliability of fat-suppressed (fs) and non-fat-suppressed (nfs) MR imaging for determination of IPFP morphological measurements as novel biomarkers. The IPFP of nine right knees of healthy Osteoarthritis Initiative participants was segmented by five readers, using fs and nfs baseline sagittal MRIs. The intra-observer reliability was determined from baseline and 1-year follow-up images. All segmentations were quality controlled (QC) by an expert reader. Reliability was expressed as root mean square coefficient of variation (RMS CV%). After QC, the inter-observer reliability for fs (nfs) imaging was 2.0% (1.1%) for IPFP volume, 2.1%/2.5% (1.6%/1.8%) for anterior/posterior surface areas, 1.8% (1.8%) for depth, and 2.1% (2.4%) for maximum sagittal area. The intra-observer reliability was 3.1% (5.0%) for volume, 2.3%/2.8% (2.5%/2.9%) for anterior/posterior surfaces, 1.9% (3.5%) for depth, and 3.3% (4.5%) for maximum sagittal area. IPFP volume from nfs images was systematically greater (+7.3%) than from fs images, but highly correlated (r = 0.98). The results suggest that quantitative measurements of IPFP morphology can be performed with satisfactory reliability when expert QC is implemented. The IPFP is more clearly depicted in nfs images, and there is a small systematic off-set versus analysis from fs images. However, the high linear relationship between fs and nfs imaging suggests that fs images can be used to analyze IPFP morphology, when nfs images are not available. PMID:26569532

The puzzling interpretation of NIR indices: The case of NaI2.21

NASA Astrophysics Data System (ADS)

Röck, B.; Vazdekis, A.; La Barbera, F.; Peletier, R. F.; Knapen, J. H.; Allende-Prieto, C.; Aguado, D. S.

2017-11-01

We present a detailed study of the Na I line strength index centred in the K band at 22 100 Å (NaI2.21 hereafter) relying on different samples of early-type galaxies. Consistent with previous studies, we find that the observed line strength indices cannot be fit by state-of-the-art scaled-solar stellar population models, even using our newly developed models in the near infrared (NIR). The models clearly underestimate the large NaI2.21 values measured for most early-type galaxies. However, we develop an Na-enhanced version of our newly developed models in the NIR, which - together with the effect of a bottom-heavy initial mass function - yield NaI2.21 indices in the range of the observations. Therefore, we suggest a scenario in which the combined effect of [Na/Fe] enhancement and a bottom-heavy initial mass function are mainly responsible for the large NaI2.21 indices observed for most early-type galaxies. To a smaller extent, also [C/Fe] enhancement might contribute to the large observed NaI2.21 values.

Motivational decline and recovery in higher education STEM courses

NASA Astrophysics Data System (ADS)

Young, Anna M.; Wendel, Paul J.; Esson, Joan M.; Plank, Kathryn M.

2018-06-01

Decline in student motivation is a concern for STEM education, especially for underrepresented groups in the sciences. Using the Science Motivation Questionnaire II, 41 foundational STEM courses were surveyed at the beginning and end of each semester in an academic year at a small primarily undergraduate university. Significant pre- to post-semester declines were observed in each of five measured motivational factors (Intrinsic motivation, Career motivation, Self determination, Self-efficacy, and Grade motivation), with effect sizes ranging from 0.21 to 0.41. However, in the second semester pre-survey, four motivational factors rebounded, including three returning to initial levels, suggesting that the observed motivational decline is not long-lasting. Analysis suggests that declines are not related to survey fatigue or student demographics, but rather to grades and, in the case of one motivational factor, to academic field. These findings suggest that a refocus on grading practices across STEM fields may influence student motivation and persistence in STEM.

Monitoring red tide with satellite imagery and numerical models: a case study in the Arabian Gulf.

PubMed

Zhao, Jun; Ghedira, Hosni

2014-02-15

A red tide event that occurred in August 2008 in the Arabian Gulf was monitored and assessed using satellite observations and numerical models. Satellite observations revealed the bloom extent and evolution from August 2008 to August 2009. Flow patterns of the bloom patch were confirmed by results from a HYCOM model. HYCOM data and satellite-derived sea surface temperature data further suggested that the bloom could have been initiated offshore and advected onshore by bottom Ekman layer. Analysis indicated that nutrient sources supporting the bloom included upwelling, Trichodesmium, and dust deposition while other potential sources of nutrient supply should also be considered. In order to monitor and detect red tide effectively and provide insights into its initiation and maintenance mechanisms, the integration of multiple platforms is required. The case study presented here demonstrated the benefit of combing satellite observations and numerical models for studying red tide outbreaks and dynamics. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Slope stability in the critical zone: The relative influence of long vs. short-time scale soil and vegetation properties on debris-flow initiation during a catastrophic rainfall.

NASA Astrophysics Data System (ADS)

Rengers, F. K.; McGuire, L.; Coe, J. A.; Kean, J. W.; Baum, R. L.; Staley, D. M.; Godt, J.

2016-12-01

Within the critical zone there is a feedback between the state of soil and vegetation development, boundary conditions (e.g. topography, climate, hillslope aspect), and biogeochemical and geophysical process fluxes. Here we explore how one process—debris flows initiated by shallow landslides—is influenced by the critical zone development state and the imposed boundary conditions. In this study, we examine a rainstorm in September 2013 in the Colorado Front Range wherein 78% of 1138 debris flows were triggered on south-facing slopes. One hypothesis is that debris-flow initiation sites are controlled by long-term soil formation and bedrock weathering, which are aspect-dependent in the Front Range. A competing hypothesis is that debris flow initiation locations are controlled by present-day vegetation patterns within the critical zone. We tested these hypotheses with a regional investigation of the Green-Red Vegetation Index (GRVI), a metric used to identify the degree of vegetation cover. Although the majority of debris flows were observed on south-facing hillslopes, the GRVI analysis revealed that most debris-flow initiation locations had low tree density and high rainfall, regardless of hillslope aspect. We next numerically simulated soil pore pressure and slope stability using the September 2013 rainfall data at one site. Results suggest that spatial variations in soil depth and the relative extent of bedrock weathering on north- versus south-facing slopes are insufficient to explain the observed spatial variations in debris flow initiation. However, decreased debris flow initiation on north-facing slopes likely resulted from increased root reinforcement provided by trees on north-facing slopes. While the current vegetation regimes in the Colorado Front Range, and throughout much of the semi-arid southwestern U.S., are superimposed on a landscape where soil development and bedrock weathering (both of which affect slope stability) are responding to longer timescale processes, our analysis suggests landslide susceptibility was primarily governed by the local, geo-mechanical effects of vegetation during this extreme rainfall event.

On the Uncertainties of the Hot Oxygen Geocorona: Ground-based 732.0-nm Observations

NASA Astrophysics Data System (ADS)

Harding, B. J.; Makela, J. J.; Meriwether, J. W.

2017-12-01

Although it is well established that Venus and Mars both have a significant hot oxygen geocorona, the evidence for a hot oxygen geocorona on Earth is sparse. Recent theoretical estimates suggest the concentration of hot oxygen at the exobase is 0.1-1% of the thermal oxygen concentration, while the observational evidence (largely from the 1980s) suggests 1-20%. There is also disagreement about the effective temperature of the hot atoms (1500-6000 K). Hot oxygen is known to affect satellite drag, ambient thermospheric temperature and circulation, and ion temperature. We show results from a recent effort to replicate the initial observation of the hot oxygen geocorona [Yee et al., 1980], using ground-based observations of the shadow height variation of the 732-nm O+ emission. Yee, J., Meriwether, J. W., & Hays, P. B. (1980). Detection of a corona of fast oxygen atoms during solar maximum. Journal of Geophysical Research, 85(80), 3396-3400.

Tip of the Tongue States Increase Under Evaluative Observation.

PubMed

James, Lori E; Schmank, Christopher J; Castro, Nichol; Buchanan, Tony W

2018-02-01

We tested the frequent assumption that the difficulty of word retrieval increases when a speaker is being observed and evaluated. We modified the Trier Social Stress Test (TSST) so that participants believed that its evaluative observation components continued throughout the duration of a subsequent word retrieval task, and measured participants' reported tip of the tongue (TOT) states. Participants in this TSST condition experienced more TOTs than participants in a comparable, placebo TSST condition in which there was no suggestion of evaluative observation. This experiment provides initial evidence confirming the assumption that evaluative observation by a third party can be disruptive to word retrieval. We interpret our findings by proposing an extension to a well-supported theoretical model of TOTs.

An 'Observational Large Ensemble' to compare observed and modeled temperature trend uncertainty due to internal variability.

NASA Astrophysics Data System (ADS)

Poppick, A. N.; McKinnon, K. A.; Dunn-Sigouin, E.; Deser, C.

2017-12-01

Initial condition climate model ensembles suggest that regional temperature trends can be highly variable on decadal timescales due to characteristics of internal climate variability. Accounting for trend uncertainty due to internal variability is therefore necessary to contextualize recent observed temperature changes. However, while the variability of trends in a climate model ensemble can be evaluated directly (as the spread across ensemble members), internal variability simulated by a climate model may be inconsistent with observations. Observation-based methods for assessing the role of internal variability on trend uncertainty are therefore required. Here, we use a statistical resampling approach to assess trend uncertainty due to internal variability in historical 50-year (1966-2015) winter near-surface air temperature trends over North America. We compare this estimate of trend uncertainty to simulated trend variability in the NCAR CESM1 Large Ensemble (LENS), finding that uncertainty in wintertime temperature trends over North America due to internal variability is largely overestimated by CESM1, on average by a factor of 32%. Our observation-based resampling approach is combined with the forced signal from LENS to produce an 'Observational Large Ensemble' (OLENS). The members of OLENS indicate a range of spatially coherent fields of temperature trends resulting from different sequences of internal variability consistent with observations. The smaller trend variability in OLENS suggests that uncertainty in the historical climate change signal in observations due to internal variability is less than suggested by LENS.

Rotational Study of Ambiguous Taxonomic Classified Asteroids

NASA Astrophysics Data System (ADS)

Linder, Tyler R.; Sanchez, Rick; Wuerker, Wolfgang; Clayson, Timothy; Giles, Tucker

2017-01-01

The Sloan Digital Sky Survey (SDSS) moving object catalog (MOC4) provided the largest ever catalog of asteroid spectrophotometry observations. Carvano et al. (2010), while analyzing MOC4, discovered that individual observations of asteroids which were observed multiple times did not classify into the same photometric-based taxonomic class. A small subset of those asteroids were classified as having both the presence and absence of a 1um silicate absorption feature. If these variations are linked to differences in surface mineralogy, the prevailing assumption that an asteroid’s surface composition is predominantly homogenous would need to be reexamined. Furthermore, our understanding of the evolution of the asteroid belt, as well as the linkage between certain asteroids and meteorite types may need to be modified.This research is an investigation to determine the rotational rates of these taxonomically ambiguous asteroids. Initial questions to be answered:Do these asteroids have unique or nonstandard rotational rates?Is there any evidence in their light curve to suggest an abnormality?Observations were taken using PROMPT6 a 0.41-m telescope apart of the SKYNET network at Cerro Tololo Inter-American Observatory (CTIO). Observations were calibrated and analyzed using Canopus software. Initial results will be presented at AAS.

Distinct roles for key karyogamy proteins during yeast nuclear fusion.

PubMed

Melloy, Patricia; Shen, Shu; White, Erin; Rose, Mark D

2009-09-01

During yeast mating, cell fusion is followed by the congression and fusion of the two nuclei. Proteins required for nuclear fusion are found at the surface (Prm3p) and within the lumen (Kar2p, Kar5p, and Kar8p) of the nuclear envelope (NE). Electron tomography (ET) of zygotes revealed that mutations in these proteins block nuclear fusion with different morphologies, suggesting that they act in different steps of fusion. Specifically, prm3 zygotes were blocked before formation of membrane bridges, whereas kar2, kar5, and kar8 zygotes frequently contained them. Membrane bridges were significantly larger and occurred more frequently in kar2 and kar8, than in kar5 mutant zygotes. The kinetics of NE fusion in prm3, kar5, and kar8 mutants, measured by live-cell fluorescence microscopy, were well correlated with the size and frequency of bridges observed by ET. However the kar2 mutant was defective for transfer of NE lumenal GFP, but not diffusion within the lumen, suggesting that transfer was blocked at the NE fusion junction. These observations suggest that Prm3p acts before initiation of outer NE fusion, Kar5p may help dilation of the initial fusion pore, and Kar2p and Kar8p act after outer NE fusion, during inner NE fusion.

Rhenium-osmium and samarium-neodymium isotopic systematics of the stillwater complex

USGS Publications Warehouse

Lambert, D.D.; Morgan, J.W.; Walker, R.J.; Shirey, S.B.; Carlson, R.W.; Zientek, M.L.; Koski, M.S.

1989-01-01

Isotopic data for the Stillwater Complex, Montana , which formed about 2700 Ma (million years ago), were obtained to evaluate the role of magma mixing in the formation of strategic platinum-group element (PGE) ore deposits. Neodymium and osmium isotopic data indicate that the intrusion formed from at least two geochemically distinct magmas. Ultramafic affinity (U-type) magmas had initial ??Nd of -0.8 to -3.2 and a chondritic initial 187Os/186Os ratio of ???0.88, whereas anorthositic affinity (A-type) magmas had ??Nd of -0.7 to +1.7 and an initial 187Os/186Os ratio of ???1.13. These data suggest that U-type magmas were derived from a lithospheric mantle source containing recycled crustal materials whereas A-type magmas originated either by crustal contamination of basaltic magmas or by partial melting of basalt in the lower crust. The Nd and Os isotopic data also suggest that Os, and probably the other PGEs in ore horizons such as the J-M Reef, was derived from A-type magmas. The Nd and Os isotopic heterogeneity observed in rocks below the J-M Reef also suggests that A-type magmas were injected into the Stillwater U-type magma chamber at several stages during the development of the Ultramafic series.

Observation of high-order quantum resonances in the kicked rotor.

PubMed

Kanem, J F; Maneshi, S; Partlow, M; Spanner, M; Steinberg, A M

2007-02-23

Quantum resonances in the kicked rotor are characterized by a dramatically increased energy absorption rate, in stark contrast to the momentum localization generally observed. These resonances occur when the scaled Planck's constant Planck's [over ]=r/s 4pi, for any integers r and s. However, only the variant Planck's [over ]=r2pi resonances are easily observable. We have observed high-order quantum resonances (s>2) utilizing a sample of low energy, noncondensed atoms and a pulsed optical standing wave. Resonances are observed for variant Planck's [over ]=r/16 4pi for integers r=2-6. Quantum numerical simulations suggest that our observation of high-order resonances indicate a larger coherence length (i.e., coherence between different wells) than expected from an initially thermal atomic sample.

Model assessing the impact of biomass burning on air quality and photochemistry in Mexico City

Treesearch

W. Lei; G. Li; C. Wiedinmyer; R. J. Yokelson; L. T. Molina

2010-01-01

Biomass burning is a major global emission source for trace gases and particulates. Various multi-platform measurements during the Mexico City Metropolitan Area (MCMA)-2003 and Megacity Initiative: Local and Global Research Observations (MILAGRO)-2006 campaigns suggest significant influences of biomass burning (BB) on air quality in Mexico City during the dry season,...

Oculomotor Evidence for Top-Down Control following the Initial Saccade

PubMed Central

Siebold, Alisha; van Zoest, Wieske; Donk, Mieke

2011-01-01

The goal of the current study was to investigate how salience-driven and goal-driven processes unfold during visual search over multiple eye movements. Eye movements were recorded while observers searched for a target, which was located on (Experiment 1) or defined as (Experiment 2) a specific orientation singleton. This singleton could either be the most, medium, or least salient element in the display. Results were analyzed as a function of response time separately for initial and second eye movements. Irrespective of the search task, initial saccades elicited shortly after the onset of the search display were primarily salience-driven whereas initial saccades elicited after approximately 250 ms were completely unaffected by salience. Initial saccades were increasingly guided in line with task requirements with increasing response times. Second saccades were completely unaffected by salience and were consistently goal-driven, irrespective of response time. These results suggest that stimulus-salience affects the visual system only briefly after a visual image enters the brain and has no effect thereafter. PMID:21931603

[Psychosocial factors associated with late HAART initiation in Mexican patients with HIV].

PubMed

Nogueda-Orozco, María José; Caro-Vega, Yanink; Crabtree-Ramírez, Brenda; Vázquez-Pineda, Fernando; Sierra-Madero, Juan G

2015-01-01

To explore the association between psychosocial factors and late highly active antiretroviral therapy (HAART) initiation in a sample of Mexican patients with HIV. We conducted a cross-sectional study at the HIV Clinic of the Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán (INCMNSZ), and applied structured questionnaires to 150 patients who initiated HAART between January 2010 and August 2011. Late HAART initiation (LHI) was considered when patients started HAART with CD4 counts of <200+ cells/mm³. By multivariate analysis, the strongest psychosocial risk factor for LHI observed was self-stigma towards HIV/AIDS. In addition, being tested by medical prescription, not by own initiative, as well as having one or more previous medical contacts, were associated with greater risk for LH. Our findings suggest the need to develop psychosocial interventions to decrease negative self-image and stigmatizing attitudes and behaviors in risk groups for HIV in Mexico.

Evaluating MyPlate: an expanded framework using traditional and nontraditional metrics for assessing health communication campaigns.

PubMed

Levine, Elyse; Abbatangelo-Gray, Jodie; Mobley, Amy R; McLaughlin, Grant R; Herzog, Jill

2012-01-01

MyPlate, the icon and multimodal communication plan developed for the 2010 Dietary Guidelines for Americans (DGA), provides an opportunity to consider new approaches to evaluating the effectiveness of communication initiatives. A review of indicators used in assessments for previous DGA communication initiatives finds gaps in accounting for important intermediate and long-term outcomes. This evaluation framework for the MyPlate Communications Initiative builds on well-known and underused models and theories to propose a wide breadth of observations, outputs, and outcomes that can contribute to a fuller assessment of effectiveness. Two areas are suggested to focus evaluation efforts in order to advance understanding of the effectiveness of the MyPlate Communications Initiative: understanding the extent to which messages and products from the initiative are associated with positive changes in social norms toward the desired behaviors, and strategies to increase the effectiveness of communications about DGA in vulnerable populations. Copyright © 2012 Society for Nutrition Education and Behavior. Published by Elsevier Inc. All rights reserved.

A Case Study of Magnetotail Conditions at Substorm and Pseudosubstorm Onsets

NASA Astrophysics Data System (ADS)

Miyashita, Y.; Angelopoulos, V.; Fukui, K.; Machida, S.

2017-12-01

While a substorm involves initial brightening and growth of wave-like structure of the auroral onset arc and the subsequent auroral poleward expansion, a pseudosubstorm (pseudobreakup) involves only the first two steps of auroral development and subsides without progressing to poleward expansion. To understand what makes this difference, we studied magnetotail conditions at a pseudosubstorm onset and the subsequent substorm onset, using multipoint Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft data. In the present event, near-Earth magnetic reconnection possibly occurred before initial brightening for both pseudosubstorm and substorm. In the near-Earth magnetotail at X -10 Re, the ion beta, ion pressure, and radial pressure gradient were smaller and magnetic field lines were less stretched at pseudosubstorm initial brightening than at substorm initial brightening. Dipolarization did not occur for the pseudosubstorm, whereas it began just before poleward expansion for the substorm. These observations suggest that conditions of the near-Earth magnetotail possibly affect whether the initial action develops into a full-fledged substorm.

Rupture preparation process controlled by surface roughness on meter-scale laboratory fault

NASA Astrophysics Data System (ADS)

Yamashita, Futoshi; Fukuyama, Eiichi; Xu, Shiqing; Mizoguchi, Kazuo; Kawakata, Hironori; Takizawa, Shigeru

2018-05-01

We investigate the effect of fault surface roughness on rupture preparation characteristics using meter-scale metagabbro specimens. We repeatedly conducted the experiments with the same pair of rock specimens to make the fault surface rough. We obtained three experimental results under the same experimental conditions (6.7 MPa of normal stress and 0.01 mm/s of loading rate) but at different roughness conditions (smooth, moderately roughened, and heavily roughened). During each experiment, we observed many stick-slip events preceded by precursory slow slip. We investigated when and where slow slip initiated by using the strain gauge data processed by the Kalman filter algorithm. The observed rupture preparation processes on the smooth fault (i.e. the first experiment among the three) showed high repeatability of the spatiotemporal distributions of slow slip initiation. Local stress measurements revealed that slow slip initiated around the region where the ratio of shear to normal stress (τ/σ) was the highest as expected from finite element method (FEM) modeling. However, the exact location of slow slip initiation was where τ/σ became locally minimum, probably due to the frictional heterogeneity. In the experiment on the moderately roughened fault, some irregular events were observed, though the basic characteristics of other regular events were similar to those on the smooth fault. Local stress data revealed that the spatiotemporal characteristics of slow slip initiation and the resulting τ/σ drop for irregular events were different from those for regular ones even under similar stress conditions. On the heavily roughened fault, the location of slow slip initiation was not consistent with τ/σ anymore because of the highly heterogeneous static friction on the fault, which also decreased the repeatability of spatiotemporal distributions of slow slip initiation. These results suggest that fault surface roughness strongly controls the rupture preparation process, and generally increases its complexity with the degree of roughness.

Mitomycin C-induced pairing of heterochromatin reflects initiation of DNA repair and chromatid exchange formation.

PubMed

Abdel-Halim, H I; Natarajan, A T; Mullenders, L H F; Boei, J J W A

2005-04-15

Chromatid interchanges induced by the DNA cross-linking agent mitomycin C (MMC) are over-represented in human chromosomes containing large heterochromatic regions. We found that nearly all exchange breakpoints of chromosome 9 are located within the paracentromeric heterochromatin and over 70% of exchanges involving chromosome 9 are between its homologues. We provide evidence that the required pairing of chromosome 9 heterochromatic regions occurs in G(0)/G(1) and S-phase cells as a result of an active cellular process initiated upon MMC treatment. By contrast, no pairing was observed for a euchromatic paracentromeric region of the equal-sized chromosome 8. The MMC-induced pairing of chromosome 9 heterochromatin is observed in a subset of cells; its percentage closely mimics the frequency of homologous interchanges found at metaphase. Moreover, the absence of pairing in cells derived from XPF patients correlates with an altered spectrum of MMC-induced exchanges. Together, the data suggest that the heterochromatin-specific pairing following MMC treatment reflects the initiation of DNA cross-link repair and the formation of exchanges.

The dependence of stellar properties on initial cloud density

NASA Astrophysics Data System (ADS)

Jones, Michael O.; Bate, Matthew R.

2018-05-01

We investigate the dependence of stellar properties on the initial mean density of the molecular cloud in which stellar clusters form using radiation hydrodynamical simulations that resolve the opacity limit for fragmentation. We have simulated the formation of three star clusters from the gravitational collapse of molecular clouds whose densities vary by a factor of a hundred. As with previous calculations including radiative feedback, we find that the dependence of the characteristic stellar mass, Mc, on the initial mean density of the cloud, ρ, is weaker than the dependence of the thermal Jeans mass. However, unlike previous calculations, which found no statistically significant variation in the median mass with density, we find a weak dependence approximately of the form Mc∝ρ-1/5. The distributions of properties of multiple systems do not vary significantly between the calculations. We compare our results to the result of observational surveys of star-forming regions, and suggest that the similarities between the properties of our lowest density calculation and the nearby Taurus-Auriga region indicate that the apparent excess of solar-type stars observed may be due to the region's low density.

Metformin selectively affects human glioblastoma tumor-initiating cell viability: A role for metformin-induced inhibition of Akt.

PubMed

Würth, Roberto; Pattarozzi, Alessandra; Gatti, Monica; Bajetto, Adirano; Corsaro, Alessandro; Parodi, Alessia; Sirito, Rodolfo; Massollo, Michela; Marini, Cecilia; Zona, Gianluigi; Fenoglio, Daniela; Sambuceti, Gianmario; Filaci, Gilberto; Daga, Antonio; Barbieri, Federica; Florio, Tullio

2013-01-01

Cancer stem cell theory postulates that a small population of tumor-initiating cells is responsible for the development, progression and recurrence of several malignancies, including glioblastoma. In this perspective, tumor-initiating cells represent the most relevant target to obtain effective cancer treatment. Metformin, a first-line drug for type II diabetes, was reported to possess anticancer properties affecting the survival of cancer stem cells in breast cancer models. We report that metformin treatment reduced the proliferation rate of tumor-initiating cell-enriched cultures isolated from four human glioblastomas. Metformin also impairs tumor-initiating cell spherogenesis, indicating a direct effect on self-renewal mechanisms. Interestingly, analyzing by FACS the antiproliferative effects of metformin on CD133-expressing subpopulation, a component of glioblastoma cancer stem cells, a higher reduction of proliferation was observed as compared with CD133-negative cells, suggesting a certain degree of cancer stem cell selectivity in its effects. In fact, glioblastoma cell differentiation strongly reduced sensitivity to metformin treatment. Metformin effects in tumor-initiating cell-enriched cultures were associated with a powerful inhibition of Akt-dependent cell survival pathway, while this pathway was not affected in differentiated cells. The specificity of metformin antiproliferative effects toward glioblastoma tumor-initiating cells was confirmed by the lack of significant inhibition of normal human stem cells (umbilical cord-derived mesenchymal stem cells) in vitro proliferation after metformin exposure. Altogether, these data clearly suggest that metformin exerts antiproliferative activity on glioblastoma cells, showing a higher specificity toward tumor-initiating cells, and that the inhibition of Akt pathway may represent a possible intracellular target of this effect.

From initiation to termination: a petrostratigraphic tour of the Ethiopian Low-Ti Flood Basalt Province

NASA Astrophysics Data System (ADS)

Krans, S. R.; Rooney, T. O.; Kappelman, J.; Yirgu, G.; Ayalew, D.

2018-05-01

Continental flood basalts (CFBs), thought to preserve the magmatic record of an impinging mantle plume head, offer spatial and temporal insights into melt generation processes in large igneous provinces (LIPs). Despite the utility of CFBs in probing mantle plume composition, these basalts typically erupt fractionated compositions, suggestive of significant residence time in the continental lithosphere. The location and duration of residence within the lithosphere provide additional insights into the flux of plume-related magmas. The NW Ethiopian plateau offers a well-preserved stratigraphic sequence from flood basalt initiation to termination, and is thus an important target for study of CFBs. This study examines modal observations within a stratigraphic framework and places these observations within the context of the magmatic evolution of the Ethiopian CFB province. Data demonstrate multiple pulses of magma recharge punctuated by brief shut-down events, with initial flows fed by magmas that experienced deeper fractionation (lower crust). Broad changes in modal mineralogy and flow cyclicity are consistent with fluctuating changes in magmatic flux through a complex plumbing system, indicating pulsed magma flux and an overall shallowing of the magmatic plumbing system over time. The composition of plagioclase megacrysts suggests a constant replenishing of new primitive magma recharging the shallow plumbing system during the main phase of volcanism, reaching an apex prior to flood basalt termination. The petrostratigraphic data sets presented in this paper provide new insight into the evolution of a magma plumbing system in a CFB province.

Effects of high CD4 cell counts on death and attrition among HIV patients receiving antiretroviral treatment: an observational cohort study.

PubMed

Tang, Zhenzhu; Pan, Stephen W; Ruan, Yuhua; Liu, Xuanhua; Su, Jinming; Zhu, Qiuying; Shen, Zhiyong; Zhang, Heng; Chen, Yi; Lan, Guanghua; Xing, Hui; Liao, Lingjie; Feng, Yi; Shao, Yiming

2017-06-09

Current WHO guidelines recommend initiating ART regardless of CD4+ cell count. In response, we conducted an observational cohort study to assess the effects of pre-ART CD4+ cell count levels on death, attrition, and death or attrition in HIV treated patients. This large HIV treatment cohort study (n = 49,155) from 2010 to 2015 was conducted in Guangxi, China. We used a Cox regression model to analyze associations between pre-ART CD4+ cell counts and death, attrition, and death or attrition. The average mortality and ART attrition rates among all treated patients were 2.63 deaths and 5.32 attritions per 100 person-years, respectively. Compared to HIV patients with <350 CD4+ cells/mm 3 at ART initiation, HIV patients with >500 CD4+ cells/mm 3 at ART initiation had a significantly lower mortality rate (Adjusted hazard ratio: 0.56, 95% CI: 0.40-0.79), but significantly higher ART attrition rate (AHR: 1.17, 95% CI: 1.03-1.33). Results from this study suggest that HIV patients with high CD4+ cell counts at the time of ART initiation may be at greater risk of treatment attrition. To further reduce ART attrition, it is imperative that patient education and healthcare provider training on ART adherence be enhanced and account for CD4 levels at ART initiation.

Live imaging of developmental processes in a living meristem of Davidia involucrata (Nyssaceae)

PubMed Central

Jerominek, Markus; Bull-Hereñu, Kester; Arndt, Melanie; Claßen-Bockhoff, Regine

2014-01-01

Morphogenesis in plants is usually reconstructed by scanning electron microscopy and histology of meristematic structures. These techniques are destructive and require many samples to obtain a consecutive series of states. Unfortunately, using this methodology the absolute timing of growth and complete relative initiation of organs remain obscure. To overcome this limitation, an in vivo observational method based on Epi-Illumination Light Microscopy (ELM) was developed and tested with a male inflorescence meristem (floral unit) of the handkerchief tree Davidia involucrata Baill. (Nyssaceae). We asked whether the most basal flowers of this floral unit arise in a basipetal sequence or, alternatively, are delayed in their development. The growing meristem was observed for 30 days, the longest live observation of a meristem achieved to date. The sequence of primordium initiation indicates a later initiation of the most basal flowers and not earlier or simultaneously as SEM images could suggest. D. involucrata exemplarily shows that live-ELM gives new insights into developmental processes of plants. In addition to morphogenetic questions such as the transition from vegetative to reproductive meristems or the absolute timing of ontogenetic processes, this method may also help to quantify cellular growth processes in the context of molecular physiology and developmental genetics studies. PMID:25431576

Live imaging of developmental processes in a living meristem of Davidia involucrata (Nyssaceae).

PubMed

Jerominek, Markus; Bull-Hereñu, Kester; Arndt, Melanie; Claßen-Bockhoff, Regine

2014-01-01

Morphogenesis in plants is usually reconstructed by scanning electron microscopy and histology of meristematic structures. These techniques are destructive and require many samples to obtain a consecutive series of states. Unfortunately, using this methodology the absolute timing of growth and complete relative initiation of organs remain obscure. To overcome this limitation, an in vivo observational method based on Epi-Illumination Light Microscopy (ELM) was developed and tested with a male inflorescence meristem (floral unit) of the handkerchief tree Davidia involucrata Baill. (Nyssaceae). We asked whether the most basal flowers of this floral unit arise in a basipetal sequence or, alternatively, are delayed in their development. The growing meristem was observed for 30 days, the longest live observation of a meristem achieved to date. The sequence of primordium initiation indicates a later initiation of the most basal flowers and not earlier or simultaneously as SEM images could suggest. D. involucrata exemplarily shows that live-ELM gives new insights into developmental processes of plants. In addition to morphogenetic questions such as the transition from vegetative to reproductive meristems or the absolute timing of ontogenetic processes, this method may also help to quantify cellular growth processes in the context of molecular physiology and developmental genetics studies.

Directed flow of charged particles at midrapidity relative to the spectator plane in Pb-Pb collisions at √(s(NN))=2.76 TeV.

PubMed

Abelev, B; Adam, J; Adamová, D; Adare, A M; Aggarwal, M M; Aglieri Rinella, G; Agnello, M; Agocs, A G; Agostinelli, A; Ahammed, Z; Ahmad, N; Ahmad Masoodi, A; Ahmed, I; Ahn, S A; Ahn, S U; Aimo, I; Ajaz, M; Akindinov, A; Aleksandrov, D; Alessandro, B; Alexandre, D; Alici, A; Alkin, A; Alme, J; Alt, T; Altini, V; Altinpinar, S; Altsybeev, I; Andrei, C; Andronic, A; Anguelov, V; Anielski, J; Anson, C; Antičić, T; Antinori, F; Antonioli, P; Aphecetche, L; Appelshäuser, H; Arbor, N; Arcelli, S; Arend, A; Armesto, N; Arnaldi, R; Aronsson, T; Arsene, I C; Arslandok, M; Asryan, A; Augustinus, A; Averbeck, R; Awes, T C; Äystö, J; Azmi, M D; Bach, M; Badalà, A; Baek, Y W; Bailhache, R; Bala, R; Baldisseri, A; Baltasar Dos Santos Pedrosa, F; Bán, J; Baral, R C; Barbera, R; Barile, F; Barnaföldi, G G; Barnby, L S; Barret, V; Bartke, J; Basile, M; Bastid, N; Basu, S; Bathen, B; Batigne, G; Batyunya, B; Batzing, P C; Baumann, C; Bearden, I G; Beck, H; Behera, N K; Belikov, I; Bellini, F; Bellwied, R; Belmont-Moreno, E; Bencedi, G; Beole, S; Berceanu, I; Bercuci, A; Berdnikov, Y; Berenyi, D; Bergognon, A A E; Bertens, R A; Berzano, D; Betev, L; Bhasin, A; Bhati, A K; Bhom, J; Bianchi, L; Bianchi, N; Bianchin, C; Bielčík, J; Bielčíková, J; Bilandzic, A; Bjelogrlic, S; Blanco, F; Blanco, F; Blau, D; Blume, C; Boccioli, M; Bock, F; Böttger, S; Bogdanov, A; Bøggild, H; Bogolyubsky, M; Boldizsár, L; Bombara, M; Book, J; Borel, H; Borissov, A; Bossú, F; Botje, M; Botta, E; Braidot, E; Braun-Munzinger, P; Bregant, M; Breitner, T; Broker, T A; Browning, T A; Broz, M; Brun, R; Bruna, E; Bruno, G E; Budnikov, D; Buesching, H; Bufalino, S; Buncic, P; Busch, O; Buthelezi, Z; Caffarri, D; Cai, X; Caines, H; Caliva, A; Calvo Villar, E; Camerini, P; Canoa Roman, V; Cara Romeo, G; Carena, F; Carena, W; Carlin Filho, N; Carminati, F; Casanova Díaz, A; Castillo Castellanos, J; Castillo Hernandez, J F; Casula, E A R; Catanescu, V; Cavicchioli, C; Ceballos Sanchez, C; Cepila, J; Cerello, P; Chang, B; Chapeland, S; Charvet, J L; Chattopadhyay, S; Chattopadhyay, S; Cherney, M; Cheshkov, C; Cheynis, B; Chibante Barroso, V; Chinellato, D D; Chochula, P; Chojnacki, M; Choudhury, S; Christakoglou, P; Christensen, C H; Christiansen, P; Chujo, T; Chung, S U; Cicalo, C; Cifarelli, L; Cindolo, F; Cleymans, J; Colamaria, F; Colella, D; Collu, A; Conesa Balbastre, G; Conesa del Valle, Z; Connors, M E; Contin, G; Contreras, J G; Cormier, T M; Corrales Morales, Y; Cortese, P; Cortés Maldonado, I; Cosentino, M R; Costa, F; Cotallo, M E; Crescio, E; Crochet, P; Cruz Alaniz, E; Cruz Albino, R; Cuautle, E; Cunqueiro, L; Czopowicz, T R; Dainese, A; Dang, R; Danu, A; Das, D; Das, I; Das, S; Das, K; Dash, A; Dash, S; De, S; de Barros, G O V; De Caro, A; de Cataldo, G; de Cuveland, J; De Falco, A; De Gruttola, D; Delagrange, H; Deloff, A; De Marco, N; Dénes, E; De Pasquale, S; Deppman, A; D'Erasmo, G; de Rooij, R; Diaz Corchero, M A; Di Bari, D; Dietel, T; Di Giglio, C; Di Liberto, S; Di Mauro, A; Di Nezza, P; Divià, R; Djuvsland, Ø; Dobrin, A; Dobrowolski, T; Dönigus, B; Dordic, O; Dubey, A K; Dubla, A; Ducroux, L; Dupieux, P; Dutta Majumdar, A K; Elia, D; Elwood, B G; Emschermann, D; Engel, H; Erazmus, B; Erdal, H A; Eschweiler, D; Espagnon, B; Estienne, M; Esumi, S; Evans, D; Evdokimov, S; Eyyubova, G; Fabris, D; Faivre, J; Falchieri, D; Fantoni, A; Fasel, M; Fehlker, D; Feldkamp, L; Felea, D; Feliciello, A; Fenton-Olsen, B; Feofilov, G; Fernández Téllez, A; Ferretti, A; Festanti, A; Figiel, J; Figueredo, M A S; Filchagin, S; Finogeev, D; Fionda, F M; Fiore, E M; Floratos, E; Floris, M; Foertsch, S; Foka, P; Fokin, S; Fragiacomo, E; Francescon, A; Frankenfeld, U; Fuchs, U; Furget, C; Fusco Girard, M; Gaardhøje, J J; Gagliardi, M; Gago, A; Gallio, M; Gangadharan, D R; Ganoti, P; Garabatos, C; Garcia-Solis, E; Gargiulo, C; Garishvili, I; Gerhard, J; Germain, M; Gheata, A; Gheata, M; Ghidini, B; Ghosh, P; Gianotti, P; Giubellino, P; Gladysz-Dziadus, E; Glässel, P; Goerlich, L; Gomez, R; Ferreiro, E G; González-Zamora, P; Gorbunov, S; Goswami, A; Gotovac, S; Graczykowski, L K; Grajcarek, R; Grelli, A; Grigoras, A; Grigoras, C; Grigoriev, V; Grigoryan, A; Grigoryan, S; Grinyov, B; Grion, N; Gros, P; Grosse-Oetringhaus, J F; Grossiord, J-Y; Grosso, R; Guber, F; Guernane, R; Guerzoni, B; Guilbaud, M; Gulbrandsen, K; Gulkanyan, H; Gunji, T; Gupta, A; Gupta, R; Haake, R; Haaland, Ø; Hadjidakis, C; Haiduc, M; Hamagaki, H; Hamar, G; Han, B H; Hanratty, L D; Hansen, A; Harris, J W; Harton, A; Hatzifotiadou, D; Hayashi, S; Hayrapetyan, A; Heckel, S T; Heide, M; Helstrup, H; Herghelegiu, A; Herrera Corral, G; Herrmann, N; Hess, B A; Hetland, K F; Hicks, B; Hippolyte, B; Hori, Y; Hristov, P; Hřivnáčová, I; Huang, M; Humanic, T J; Hwang, D S; Ichou, R; Ilkaev, R; Ilkiv, I; Inaba, M; Incani, E; Innocenti, P G; Innocenti, G M; Ionita, C; Ippolitov, M; Irfan, M; Ivanov, V; Ivanov, M; Ivanov, A; Ivanytskyi, O; Jachołkowski, A; Jacobs, P M; Jahnke, C; Jang, H J; Janik, M A; Jayarathna, P H S Y; Jena, S; Jha, D M; Jimenez Bustamante, R T; Jones, P G; Jung, H; Jusko, A; Kaidalov, A B; Kalcher, S; Kaliňák, P; Kalliokoski, T; Kalweit, A; Kang, J H; Kaplin, V; Kar, S; Karasu Uysal, A; Karavichev, O; Karavicheva, T; Karpechev, E; Kazantsev, A; Kebschull, U; Keidel, R; Ketzer, B; Khan, M M; Khan, P; Khan, K H; Khan, S A; Khanzadeev, A; Kharlov, Y; Kileng, B; Kim, J S; Kim, B; Kim, T; Kim, D J; Kim, S; Kim, M; Kim, D W; Kim, J H; Kim, M; Kirsch, S; Kisel, I; Kiselev, S; Kisiel, A; Kiss, G; Klay, J L; Klein, J; Klein-Bösing, C; Kliemant, M; Kluge, A; Knichel, M L; Knospe, A G; Köhler, M K; Kollegger, T; Kolojvari, A; Kompaniets, M; Kondratiev, V; Kondratyeva, N; Konevskikh, A; Kovalenko, V; Kowalski, M; Kox, S; Koyithatta Meethaleveedu, G; Kral, J; Králik, I; Kramer, F; Kravčáková, A; Krelina, M; Kretz, M; Krivda, M; Krizek, F; Krus, M; Kryshen, E; Krzewicki, M; Kucera, V; Kucheriaev, Y; Kugathasan, T; Kuhn, C; Kuijer, P G; Kulakov, I; Kumar, J; Kurashvili, P; Kurepin, A; Kurepin, A B; Kuryakin, A; Kushpil, S; Kushpil, V; Kvaerno, H; Kweon, M J; Kwon, Y; Ladrón de Guevara, P; Lagana Fernandes, C; Lakomov, I; Langoy, R; La Pointe, S L; Lara, C; Lardeux, A; La Rocca, P; Lea, R; Lechman, M; Lee, G R; Lee, S C; Legrand, I; Lehnert, J; Lemmon, R C; Lenhardt, M; Lenti, V; León, H; Leoncino, M; León Monzón, I; Lévai, P; Li, S; Lien, J; Lietava, R; Lindal, S; Lindenstruth, V; Lippmann, C; Lisa, M A; Ljunggren, H M; Lodato, D F; Loenne, P I; Loggins, V R; Loginov, V; Lohner, D; Loizides, C; Loo, K K; Lopez, X; López Torres, E; Løvhøiden, G; Lu, X-G; Luettig, P; Lunardon, M; Luo, J; Luparello, G; Luzzi, C; Ma, R; Ma, K; Madagodahettige-Don, D M; Maevskaya, A; Mager, M; Mahapatra, D P; Maire, A; Malaev, M; Maldonado Cervantes, I; Malinina, L; Mal'kevich, D; Malzacher, P; Mamonov, A; Manceau, L; Mangotra, L; Manko, V; Manso, F; Manzari, V; Marchisone, M; Mareš, J; Margagliotti, G V; Margotti, A; Marín, A; Markert, C; Marquard, M; Martashvili, I; Martin, N A; Martin Blanco, J; Martinengo, P; Martínez, M I; Martínez García, G; Martynov, Y; Mas, A; Masciocchi, S; Masera, M; Masoni, A; Massacrier, L; Mastroserio, A; Matyja, A; Mayer, C; Mazer, J; Mazumder, R; Mazzoni, M A; Meddi, F; Menchaca-Rocha, A; Mercado Pérez, J; Meres, M; Miake, Y; Mikhaylov, K; Milano, L; Milosevic, J; Mischke, A; Mishra, A N; Miśkowiec, D; Mitu, C; Mlynarz, J; Mohanty, B; Molnar, L; Montaño Zetina, L; Monteno, M; Montes, E; Moon, T; Morando, M; Moreira De Godoy, D A; Moretto, S; Morreale, A; Morsch, A; Muccifora, V; Mudnic, E; Muhuri, S; Mukherjee, M; Müller, H; Munhoz, M G; Murray, S; Musa, L; Musinsky, J; Nandi, B K; Nania, R; Nappi, E; Nasar, M; Nattrass, C; Nayak, T K; Nazarenko, S; Nedosekin, A; Nicassio, M; Niculescu, M; Nielsen, B S; Nikolaev, S; Nikolic, V; Nikulin, V; Nikulin, S; Nilsen, B S; Nilsson, M S; Noferini, F; Nomokonov, P; Nooren, G; Nyanin, A; Nyatha, A; Nygaard, C; Nystrand, J; Ochirov, A; Oeschler, H; Oh, S K; Oh, S; Olah, L; Oleniacz, J; Oliveira Da Silva, A C; Onderwaater, J; Oppedisano, C; Ortiz Velasquez, A; Oskarsson, A; Ostrowski, P; Otwinowski, J; Oyama, K; Ozawa, K; Pachmayer, Y; Pachr, M; Padilla, F; Pagano, P; Paić, G; Painke, F; Pajares, C; Pal, S K; Palaha, A; Palmeri, A; Papikyan, V; Pappalardo, G S; Park, W J; Passfeld, A; Patalakha, D I; Paticchio, V; Paul, B; Pavlinov, A; Pawlak, T; Peitzmann, T; Pereira Da Costa, H; Pereira De Oliveira Filho, E; Peresunko, D; Pérez Lara, C E; Perrino, D; Peryt, W; Pesci, A; Pestov, Y; Petráček, V; Petran, M; Petris, M; Petrov, P; Petrovici, M; Petta, C; Piano, S; Pikna, M; Pillot, P; Pinazza, O; Pinsky, L; Pitz, N; Piyarathna, D B; Planinic, M; Płoskoń, M; Pluta, J; Pocheptsov, T; Pochybova, S; Podesta-Lerma, P L M; Poghosyan, M G; Polák, K; Polichtchouk, B; Poljak, N; Pop, A; Porteboeuf-Houssais, S; Pospíšil, V; Potukuchi, B; Prasad, S K; Preghenella, R; Prino, F; Pruneau, C A; Pshenichnov, I; Puddu, G; Punin, V; Putschke, J; Qvigstad, H; Rachevski, A; Rademakers, A; Rak, J; Rakotozafindrabe, A; Ramello, L; Raniwala, S; Raniwala, R; Räsänen, S S; Rascanu, B T; Rathee, D; Rauch, W; Rauf, A W; Razazi, V; Read, K F; Real, J S; Redlich, K; Reed, R J; Rehman, A; Reichelt, P; Reicher, M; Reidt, F; Renfordt, R; Reolon, A R; Reshetin, A; Rettig, F; Revol, J-P; Reygers, K; Riccati, L; Ricci, R A; Richert, T; Richter, M; Riedler, P; Riegler, W; Riggi, F; Rivetti, A; Rodríguez Cahuantzi, M; Rodriguez Manso, A; Røed, K; Rogochaya, E; Rohr, D; Röhrich, D; Romita, R; Ronchetti, F; Rosnet, P; Rossegger, S; Rossi, A; Roy, P; Roy, C; Rubio Montero, A J; Rui, R; Russo, R; Ryabinkin, E; Rybicki, A; Sadovsky, S; Safařík, K; Sahoo, R; Sahu, P K; Saini, J; Sakaguchi, H; Sakai, S; Sakata, D; Salgado, C A; Salzwedel, J; Sambyal, S; Samsonov, V; Sanchez Castro, X; Sándor, L; Sandoval, A; Sano, M; Santagati, G; Santoro, R; Sarkar, D; Scapparone, E; Scarlassara, F; Scharenberg, R P; Schiaua, C; Schicker, R; Schmidt, C; Schmidt, H R; Schuchmann, S; Schukraft, J; Schulc, M; Schuster, T; Schutz, Y; Schwarz, K; Schweda, K; Scioli, G; Scomparin, E; Scott, P A; Scott, R; Segato, G; Selyuzhenkov, I; Senyukov, S; Seo, J; Serci, S; Serradilla, E; Sevcenco, A; Shabetai, A; Shabratova, G; Shahoyan, R; Sharma, N; Sharma, S; Rohni, S; Shigaki, K; Shtejer, K; Sibiriak, Y; Siddhanta, S; Siemiarczuk, T; Silvermyr, D; Silvestre, C; Simatovic, G; Simonetti, G; Singaraju, R; Singh, R; Singha, S; Singhal, V; Sinha, T; Sinha, B C; Sitar, B; Sitta, M; Skaali, T B; Skjerdal, K; Smakal, R; Smirnov, N; Snellings, R J M; Søgaard, C; Soltz, R; Song, J; Song, M; Soos, C; Soramel, F; Spacek, M; Sputowska, I; Spyropoulou-Stassinaki, M; Srivastava, B K; Stachel, J; Stan, I; Stefanek, G; Steinpreis, M; Stenlund, E; Steyn, G; Stiller, J H; Stocco, D; Stolpovskiy, M; Strmen, P; Suaide, A A P; Subieta Vásquez, M A; Sugitate, T; Suire, C; Suleymanov, M; Sultanov, R; Sumbera, M; Susa, T; Symons, T J M; Szanto de Toledo, A; Szarka, I; Szczepankiewicz, A; Szymański, M; Takahashi, J; Tangaro, M A; Tapia Takaki, J D; Tarantola Peloni, A; Tarazona Martinez, A; Tauro, A; Tejeda Muñoz, G; Telesca, A; Ter Minasyan, A; Terrevoli, C; Thäder, J; Thomas, D; Tieulent, R; Timmins, A R; Tlusty, D; Toia, A; Torii, H; Toscano, L; Trubnikov, V; Truesdale, D; Trzaska, W H; Tsuji, T; Tumkin, A; Turrisi, R; Tveter, T S; Ulery, J; Ullaland, K; Ulrich, J; Uras, A; Urciuoli, G M; Usai, G L; Vajzer, M; Vala, M; Valencia Palomo, L; Vallero, S; Vande Vyvre, P; Van Hoorne, J W; van Leeuwen, M; Vannucci, L; Vargas, A; Varma, R; Vasileiou, M; Vasiliev, A; Vechernin, V; Veldhoen, M; Venaruzzo, M; Vercellin, E; Vergara, S; Vernet, R; Verweij, M; Vickovic, L; Viesti, G; Viinikainen, J; Vilakazi, Z; Villalobos Baillie, O; Vinogradov, Y; Vinogradov, A; Vinogradov, L; Virgili, T; Viyogi, Y P; Vodopyanov, A; Völkl, M A; Voloshin, K; Voloshin, S; Volpe, G; von Haller, B; Vorobyev, I; Vranic, D; Vrláková, J; Vulpescu, B; Vyushin, A; Wagner, B; Wagner, V; Wagner, J; Wang, Y; Wang, M; Wang, Y; Watanabe, D; Watanabe, K; Weber, M; Wessels, J P; Westerhoff, U; Wiechula, J; Wielanek, D; Wikne, J; Wilde, M; Wilk, G; Wilkinson, J; Williams, M C S; Winn, M; Windelband, B; Xiang, C; Yaldo, C G; Yamaguchi, Y; Yang, H; Yang, S; Yang, P; Yano, S; Yasnopolskiy, S; Yi, J; Yin, Z; Yoo, I-K; Yoon, J; Yushmanov, I; Zaccolo, V; Zach, C; Zampolli, C; Zaporozhets, S; Zarochentsev, A; Závada, P; Zaviyalov, N; Zbroszczyk, H; Zelnicek, P; Zgura, I S; Zhalov, M; Zhang, Y; Zhang, X; Zhang, F; Zhang, H; Zhou, Y; Zhou, F; Zhou, D; Zhu, H; Zhu, X; Zhu, J; Zhu, J; Zichichi, A; Zimmermann, A; Zinovjev, G; Zoccarato, Y; Zynovyev, M; Zyzak, M

2013-12-06

The directed flow of charged particles at midrapidity is measured in Pb-Pb collisions at √(s(NN))=2.76 TeV relative to the collision symmetry plane defined by the spectator nucleons. A negative slope of the rapidity-odd directed flow component with approximately 3 times smaller magnitude than found at the highest RHIC energy is observed. This suggests a smaller longitudinal tilt of the initial system and disfavors the strong fireball rotation predicted for the LHC energies. The rapidity-even directed flow component is measured for the first time with spectators and found to be independent of pseudorapidity with a sign change at transverse momenta p(T) between 1.2 and 1.7  GeV/c. Combined with the observation of a vanishing rapidity-even p(T) shift along the spectator deflection this is strong evidence for dipolelike initial density fluctuations in the overlap zone of the nuclei. Similar trends in the rapidity-even directed flow and the estimate from two-particle correlations at midrapidity, which is larger by about a factor of 40, indicate a weak correlation between fluctuating participant and spectator symmetry planes. These observations open new possibilities for investigation of the initial conditions in heavy-ion collisions with spectator nucleons.

Incorporating TPC observed parameters and QuikSCAT surface wind observations into hurricane initialization using 4D-VAR approaches

NASA Astrophysics Data System (ADS)

Park, Kyungjeen

This study aims to develop an objective hurricane initialization scheme which incorporates not only forecast model constraints but also observed features such as the initial intensity and size. It is based on the four-dimensional variational (4D-Var) bogus data assimilation (BDA) scheme originally proposed by Zou and Xiao (1999). The 4D-Var BDA consists of two steps: (i) specifying a bogus sea level pressure (SLP) field based on parameters observed by the Tropical Prediction Center (TPC) and (ii) assimilating the bogus SLP field under a forecast model constraint to adjust all model variables. This research focuses on improving the specification of the bogus SLP indicated in the first step. Numerical experiments are carried out for Hurricane Bonnie (1998) and Hurricane Gordon (2000) to test the sensitivity of hurricane track and intensity forecasts to specification of initial vortex. Major results are listed below: (1) A linear regression model is developed for determining the size of initial vortex based on the TPC observed radius of 34kt. (2) A method is proposed to derive a radial profile of SLP from QuikSCAT surface winds. This profile is shown to be more realistic than ideal profiles derived from Fujita's and Holland's formulae. (3) It is found that it takes about 1 h for hurricane prediction model to develop a conceptually correct hurricane structure, featuring a dominant role of hydrostatic balance at the initial time and a dynamic adjustment in less than 30 minutes. (4) Numerical experiments suggest that track prediction is less sensitive to the specification of initial vortex structure than intensity forecast. (5) Hurricane initialization using QuikSCAT-derived initial vortex produced a reasonably good forecast for hurricane landfall, with a position error of 25 km and a 4-h delay at landfalling. (6) Numerical experiments using the linear regression model for the size specification considerably outperforms all the other formulations tested in terms of the intensity prediction for both Hurricanes. For examples, the maximum track error is less than 110 km during the entire three-day forecasts for both hurricanes. The simulated Hurricane Gordon using the linear regression model made a nearly perfect landfall, with no position error and only 1-h error in landfalling time. (7) Diagnosis of model output indicates that the initial vortex specified by the linear regression model produces larger surface fluxes of sensible heat, latent heat and moisture, as well as stronger downward angular momentum transport than all the other schemes do. These enhanced energy supplies offset the energy lost caused by friction and gravity wave propagation, allowing for the model to maintain a strong and realistic hurricane during the entire forward model integration.

Can even-order laser harmonics exhibited by Bohmian trajectories in symmetric potentials be observed?

PubMed

Peatross, J; Johansen, J

2014-01-13

Strong-field laser-atom interactions provide extreme conditions that may be useful for investigating the de Broglie-Bohm quantum interpretation. Bohmian trajectories representing bound electrons in individual atoms exhibit both even and odd harmonic motion when subjected to a strong external laser field. The phases of the even harmonics depend on the random initial positions of the trajectories within the wave function, making the even harmonics incoherent. In contrast, the phases of odd harmonics remain for the most part coherent regardless of initial position. Under the conjecture that a Bohmian point particle plays the role of emitter, this suggests an experiment to determine whether both even and odd harmonics are produced at the atomic level. Estimates suggest that incoherent emission of even harmonics may be detectable out the side of an intense laser focus interacting with a large number of atoms.

AN EVOLVING STELLAR INITIAL MASS FUNCTION AND THE GAMMA-RAY BURST REDSHIFT DISTRIBUTION

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

Wang, F. Y.; Dai, Z. G.

2011-02-01

Recent studies suggest that Swift gamma-ray bursts (GRBs) may not trace an ordinary star formation history (SFH). Here, we show that the GRB rate turns out to be consistent with the SFH with an evolving stellar initial mass function (IMF). We first show that the latest Swift sample of GRBs reveals an increasing evolution in the GRB rate relative to the ordinary star formation rate at high redshifts. We then assume only massive stars with masses greater than the critical value to produce GRBs and use an evolving stellar IMF suggested by Dave to fit the latest GRB redshift distribution.more » This evolving IMF would increase the relative number of massive stars, which could lead to more GRB explosions at high redshifts. We find that the evolving IMF can well reproduce the observed redshift distribution of Swift GRBs.« less

Social and Contextual Constraints on Embodied Perception.

PubMed

Schnall, Simone

2017-03-01

A number of papers have challenged research on physiological and psychological influences on perception by claiming to show that such findings can be explained by nonperceptual factors such as demand characteristics. Relatedly, calls for separating perception from judgment have been issued. However, such efforts fail to consider key processes known to shape judgment processes: people's inability to report accurately on their judgments, conversational dynamics of experimental research contexts, and misattribution and discounting processes. Indeed, the fact that initially observed effects of embodied influences disappear is predicted by an extensive amount of literature on judgments studied within social psychology. Thus, findings from such studies suggest that the initially presumed underlying processes are at work-namely, functional considerations that are informative in the context of preparing the body for action. In this article, I provide suggestions on how to conduct research on perception within the social constraints of experimental contexts.

Synchronous termination of replication of the two chromosomes is an evolutionary selected feature in Vibrionaceae

PubMed Central

Kemter, Franziska S.; Messerschmidt, Sonja J.; Schallopp, Nadine; Sobetzko, Patrick; Bunk, Boyke; Spröer, Cathrin; Teschler, Jennifer K.; Yildiz, Fitnat H.

2018-01-01

Vibrio cholerae, the causative agent of the cholera disease, is commonly used as a model organism for the study of bacteria with multipartite genomes. Its two chromosomes of different sizes initiate their DNA replication at distinct time points in the cell cycle and terminate in synchrony. In this study, the time-delayed start of Chr2 was verified in a synchronized cell population. This replication pattern suggests two possible regulation mechanisms for other Vibrio species with different sized secondary chromosomes: Either all Chr2 start DNA replication with a fixed delay after Chr1 initiation, or the timepoint at which Chr2 initiates varies such that termination of chromosomal replication occurs in synchrony. We investigated these two models and revealed that the two chromosomes of various Vibrionaceae species terminate in synchrony while Chr2-initiation timing relative to Chr1 is variable. Moreover, the sequence and function of the Chr2-triggering crtS site recently discovered in V. cholerae were found to be conserved, explaining the observed timing mechanism. Our results suggest that it is beneficial for bacterial cells with multiple chromosomes to synchronize their replication termination, potentially to optimize chromosome related processes as dimer resolution or segregation. PMID:29505558

The initiation of lateral roots in the primary roots of maize (Zea mays L.) implies a reactivation of cell proliferation in a group of founder pericycle cells.

PubMed

Alarcón, M Victoria; Lloret, Pedro G; Martín-Partido, Gervasio; Salguero, Julio

2016-03-15

The initiation of lateral roots (LRs) has generally been viewed as a reactivation of proliferative activity in pericycle cells that are committed to initiate primordia. However, it is also possible that pericycle founder cells that initiate LRs never cease proliferative activity but rather are displaced to the most distal root zones while undertaking successive stages of LR initiation. In this study, we tested these two alternative hypotheses by examining the incorporation of 5-bromo-2'-deoxyuridine (BrdU) into the DNA of meristematic root cells of Zea mays. According to the values for the length of the cell cycle and values for cell displacement along the maize root, our results strongly suggest that pericycle cells that initiate LR primordia ceased proliferative activity upon exiting the meristematic zone. This finding is supported by the existence of a root zone between 4 and 20mm from the root cap junction, in which neither mitotic cells nor labelled nuclei were observed in phloem pericycle cells. Copyright © 2016 Elsevier GmbH. All rights reserved.

Exclusively visual analysis of classroom group interactions

NASA Astrophysics Data System (ADS)

Tucker, Laura; Scherr, Rachel E.; Zickler, Todd; Mazur, Eric

2016-12-01

Large-scale audiovisual data that measure group learning are time consuming to collect and analyze. As an initial step towards scaling qualitative classroom observation, we qualitatively coded classroom video using an established coding scheme with and without its audio cues. We find that interrater reliability is as high when using visual data only—without audio—as when using both visual and audio data to code. Also, interrater reliability is high when comparing use of visual and audio data to visual-only data. We see a small bias to code interactions as group discussion when visual and audio data are used compared with video-only data. This work establishes that meaningful educational observation can be made through visual information alone. Further, it suggests that after initial work to create a coding scheme and validate it in each environment, computer-automated visual coding could drastically increase the breadth of qualitative studies and allow for meaningful educational analysis on a far greater scale.

[Defibrotide therapy for patients with sinusoidal obstruction syndrome after hematopoietic stem cell transplantation].

PubMed

Yakushijin, Kimikazu; Okamura, Atsuo; Ono, Kanako; Kawano, Yuko; Kawano, Hiroki; Funakoshi, Yohei; Kawamori, Yuriko; Nishikawa, Shinichiro; Minagawa, Kentaro; Sada, Akiko; Shimoyama, Manabu; Yamamoto, Katsuya; Katayama, Yoshio; Matsui, Toshimitsu

2009-01-01

Sinusoidal obstruction syndrome (SOS) is one of the life-threatening complications caused by endothelial damage to the hepatic sinusoids after hematopoietic stem cell transplantation. However, a satisfactory treatment for SOS has not yet been established. Defibrotide has anti-thrombotic, anti-ischemic, anti-inflammatory, and thrombolytic properties without systemic anticoagulant effects. We treated eight post-transplant SOS patients with defibrotide. Three patients responded to the therapy and the initial response was observed within a week. In addition to the improvement of liver function, rapid recovery of response to diuretic drugs followed by the improvement of renal function was observed. All of the five patients with respiratory dysfunction died despite administration of defibrotide, suggesting that early treatment might lead to better outcomes. There were no severe adverse effects directly due to defibrotide administration. Defibrotide seems to be a promising treatment for SOS, and the initiation of a clinical study in Japan would be important.

Initiation of deformation of the Eastern California Shear Zone: Constraints from Garlock fault geometry and GPS observations

USGS Publications Warehouse

Gan, Weijun; Zhang, P.; Shen, Z.-K.; Prescott, W.H.; Svarc, J.L.

2003-01-01

We suggest a 2-stage deformation model for the Eastern California Shear Zone (ECSZ) to explain the geometry of the Garlock fault trace. We assume the Garlock fault was originally straight and then was gradually curved by right-lateral shear deformation across the ECSZ. In our 2-stage deformation model, the first stage involves uniform shear deformation across the eastern part of the shear zone, and the second stage involves uniform shear deformation across the entire shear zone. In addition to the current shape of the Garlock fault, our model incorporates constraints on contemporary deformation rates provided by GPS observations. We find that the best fitting age for initiation of shear in eastern part of the ECSZ is about 5.0 ?? 0.4 Ma, and that deformation of the western part started about 1.6 Myr later.

Sulfur-bearing coatings on fly ash from a coal-fired power plant: Composition, origin, and influence on ash alteration

USGS Publications Warehouse

Fishman, N.S.; Rice, C.A.; Breit, G.N.; Johnson, R.D.

1999-01-01

Fly ash samples collected from two locations in the exhaust stream of a coal-fired power plant differ markedly with respect to the abundance of thin (???0.1 ??m) sulfur-rich surface coatings that are observable by scanning electron microscopy. The coatings, tentatively identified as an aluminum-potassium-sulfate phase, probably form upon reaction between condensed sulfuric acid aerosols and glass surfaces, and are preferentially concentrated on ash exposed to exhaust stream gases for longer. The coatings are highly soluble and if sufficiently abundant, can impart an acidic pH to solutions initially in contact with ash. These observations suggest that proposals for ash use and predictions of ash behavior during disposal should consider the transient, acid-generating potential of some ash fractions and the possible effects on initial ash leachability and alteration. ?? 1998 Elsevier Science Ltd.

The US Arctic Observing Network - Mobilizing Interagency Observing Actions in an Era of Rapid Change

NASA Astrophysics Data System (ADS)

Starkweather, S.

2017-12-01

US agencies have long relied upon sustained Arctic observing to achieve their missions, be they in support of long-term monitoring, operationalized forecasts, or long-term process studies. One inventory of Arctic observing activities (arcticobservingviewer.org) suggests that there are more than 10,000 sustained data collection sites that have been supported by US agencies. Yet despite calls from academia (e.g. National Research Council, 2006) and agency leadership (e.g. IARPC, 2007) for more integrated approaches, such coherence - in the form of a US Arctic Observing Network (US AON) - has been slow and ad hoc in emerging. Two approaches have been invoked in systematically creating networks of greater coherence. One involves solving the "backward problem" or drawing existing observations into interoperable, multi-sensor, value-added data products. These approaches have the benefit that they build from existing assets and extend observations over greater time and space scales than individual efforts can approach. They suffer from being high-energy undertakings, often proceeding through voluntary efforts, and are limited by the observational assets already in place. Solving the "forward problem", or designing the network that is "needed" entails its own challenges of aligning multiple agency needs and capabilities into coordinated frameworks, often tied into a societal benefit structure. The solutions to the forward problem are greatly constrained by financial and technical feasibility. The benefit of such approaches is that interoperability and user-needs are baked into the network design, and some critical prioritization has been invoked. In September 2016, NOAA and other US agencies advanced plans to formally establish and fund the coordination of a US AON initiative. This US AON initiative brings new coordination capabilities on-line to support and strengthen US engagement in sustained and coordinated pan-Arctic observing and data sharing systems that serve societal needs. This work describes the capabilities of the new US AON initiative and how those capabilities are being mobilized towards both the "backward" and "forward" problems of Arctic observing.

Observed Luminosity Spread in Young Clusters and FU Ori Stars: A Unified Picture

NASA Astrophysics Data System (ADS)

Baraffe, I.; Vorobyov, E.; Chabrier, G.

2012-09-01

The idea that non-steady accretion during the embedded phase of protostar evolution can produce the observed luminosity spread in the Herzsprung-Russell diagram (HRD) of young clusters has recently been called into question. Observations of FU Ori, for instance, suggest an expansion of the star during strong accretion events, whereas the luminosity spread implies a contraction of the accreting objects, decreasing their radiating surface. In this paper, we present a global scenario based on calculations coupling episodic accretion histories derived from numerical simulations of collapsing cloud prestellar cores of various masses and subsequent protostar evolution. Our calculations show that, assuming an initial protostar mass Mi ~ 1 M Jup, typical of the second Larson's core, both the luminosity spread in the HRD and the inferred properties of FU Ori events (mass, radius, accretion rate) can be explained by this scenario, providing two conditions. First, there must be some variation within the fraction of accretion energy absorbed by the protostar during the accretion process. Second, the range of this variation should increase with increasing accretion burst intensity and thus with the initial core mass and final star mass. The numerical hydrodynamics simulations of collapsing cloud prestellar cores indeed show that the intensity of the accretion bursts correlates with the mass and initial angular momentum of the prestellar core. Massive prestellar cores with high initial angular momentum are found to produce intense bursts characteristic of FU Ori-like events. Our results thus suggest a link between the burst intensities and the fraction of accretion energy absorbed by the protostar, with some threshold in the accretion rate, of the order of 10-5 M ⊙ yr-1, delimitating the transition from "cold" to "hot" accretion. Such a transition might reflect a change in the accretion geometry with increasing accretion rate, i.e., a transition from magnetospheric or thin-disk to thick-disk accretion, or in the magnetospheric interaction between the star and the disk. Conversely, the luminosity spread can also be explained by a variation of the initial protostar mass within the ~1-5 M Jup range, although it is unclear for now whether such a spread among the second Larson's core can be produced during the prestellar core second collapse. This unified picture confirms the idea that early accretion during protostar and proto-brown dwarf formation/evolution can explain the observed luminosity spread in young clusters without invoking any significant age spread, and that the concept of a well-defined birthline does not apply for low-mass objects. Finally, we examine the impact of accretion on the determination of the initial mass function in young clusters.

Creating unstable velocity-space distributions with barium injections

NASA Technical Reports Server (NTRS)

Pongratz, M. B.

1983-01-01

Ion velocity-space distributions resulting from barium injections from orbiting spacecraft and shaped charges are discussed. Active experiments confirm that anomalous ionization processes may operate, but photoionization accounts for the production of the bulk of the barium ions. Pitch-angle diffusion and/or velocity-space diffusion may occur, but observations of barium ions moving upwards against gravity suggests that the ions retain a significant enough fraction of their initial perpendicular velocity to provide a mirror force. The barium ion plasmas should have a range of Alfven Mach numbers and plasma betas. Because the initial conditions can be predicted these active experiments should permit testing plasma instability hypotheses.

The difference in LET and ion species dependence for induction of initially measured and non-rejoined chromatin breaks in normal human fibroblasts.

PubMed

Tsuruoka, Chizuru; Suzuki, Masao; Hande, M Prakash; Furusawa, Yoshiya; Anzai, Kazunori; Okayasu, Ryuichi

2008-08-01

We studied the LET and ion species dependence of the induction of chromatin breaks measured immediately after irradiation as initially measured breaks and after 24 h postirradiation incubation (37 degrees C) as non-rejoined breaks in normal human fibroblasts with different heavy ions, such as carbon, neon, silicon and iron, generated by the Heavy Ion Medical Accelerator in Chiba (HIMAC) at the National Institute of Radiological Science (NIRS). Chromatin breaks were measured as an excess number of fragments of prematurely condensed chromosomes using premature chromosome condensation (PCC). The results showed that the number of excess fragments per cell per Gy for initially measured chromatin breaks was dependent on LET in the range from 13.3 to 113.1 keV/mum but was not dependent on ion species. On the other hand, the number of non-rejoined chromatin breaks detected after 24 h postirradiation incubation was clearly dependent on both LET and ion species. No significant difference was observed in the cross section for initially measured breaks, but a statistically significant difference was observed in the cross section for non-rejoined breaks among carbon, neon, silicon and iron ions. This suggests that the LET-dependent structure in the biological effects is reflected in biological consequences of repair processes.

Mechanisms initiating deep convection over complex terrain during COPS.

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

Kottmeier, C.; Kalthoff, N.; Barthlott, C.

2008-12-01

Precipitating convection in a mountain region of moderate topography is investigated, with particular emphasis on its initiation in response to boundary-layer and mid- and upper-tropospheric forcing mechanisms. The data used in the study are from COPS (Convective and Orographically-induced Precipitation Study) that took place in southwestern Germany and eastern France in the summer of 2007. It is found that the initiation of precipitating convection can be roughly classified as being due to either: (i) surface heating and low-level flow convergence; (ii) surface heating and moisture supply overcoming convective inhibition during latent and/or potential instability; or (iii) mid-tropospheric dynamical processes duemore » to mesoscale convergence lines and forced mean vertical motion. These phenomena have to be adequately represented in models in order to improve quantitative precipitation forecast. Selected COPS cases are analyzed and classified into these initiation categories. Although only a subset of COPS data (mainly radiosondes, surface weather stations, radar and satellite data) are used here, it is shown that convective systems are captured in considerable detail by sensor synergy. Convergence lines were observed by Doppler radar in the location where deep convection is triggered several hours later. The results suggest that in many situations, observations of the location and timing of convergence lines will facilitate the nowcasting of convection. Further on, forecasting of the initiation of convection is significantly complicated if advection of potentially convective air masses over changing terrain features plays a major role. The passage of a frontal structure over the Vosges - Rhine valley - Black Forest orography was accompanied by an intermediate suppression of convection over the wide Rhine valley. Further downstream, an intensification of convection was observed over the Black Forest due to differential surface heating, a convergence line, and the flow generated by a gust front.« less

Changes to Saccade Behaviors in Parkinson’s Disease Following Dancing and Observation of Dancing

PubMed Central

Cameron, Ian G. M.; Brien, Donald C.; Links, Kira; Robichaud, Sarah; Ryan, Jennifer D.; Munoz, Douglas P.; Chow, Tiffany W.

2012-01-01

Background: The traditional view of Parkinson’s disease (PD) as a motor disorder only treated by dopaminergic medications is now shifting to include non-pharmacologic interventions. We have noticed that patients with PD obtain an immediate, short-lasting benefit to mobility by the end of a dance class, suggesting some mechanism by which dancing reduces bradykinetic symptoms. We have also found that patients with PD are unimpaired at initiating highly automatic eye movements to visual stimuli (pro-saccades) but are impaired at generating willful eye movements away from visual stimuli (anti-saccades). We hypothesized that the mechanisms by which a dance class improves movement initiation may generalize to the brain networks impacted in PD (frontal lobe and basal ganglia, BG), and thus could be assessed objectively by measuring eye movements, which rely on the same neural circuitry. Methods: Participants with PD performed pro- and anti-saccades before, and after, a dance class. “Before” and “after” saccade performance measurements were compared. These measurements were then contrasted with a control condition (observing a dance class in a video), and with older and younger adult populations, who rested for an hour between measurements. Results: We found an improvement in anti-saccade performance following the observation of dance (but not following dancing), but we found a detriment in pro-saccade performance following dancing. Conclusion: We suggest that observation of dance induced plasticity changes in frontal-BG networks that are important for executive control. Dancing, in contrast, increased voluntary movement signals that benefited mobility, but interfered with the automaticity of efficient pro-saccade execution. PMID:23483834

3 micron spectrophotometry of Comet Halley - Evidence for water ice

NASA Technical Reports Server (NTRS)

Bregman, Jesse D.; Tielens, A. G. G. M.; Witteborn, Fred C.; Rank, David M.; Wooden, Diane

1988-01-01

Structure has been observed in the 3-3.6 micron preperihelion spectrum of Comet Halley consistent with either an absorption band near 3.1 microns or emission near 3.3 microns. The results suggest that a large fraction of the water molecules lost by the comet are initially ejected in the form of small ice particles rather than in the gas phase.

Pyroxenes as recorders of lunar basalt petrogenesis - Chemical trends due to crystal-liquid interaction.

NASA Technical Reports Server (NTRS)

Bence, A. E.; Papike, J. J.

1972-01-01

Review of the crystallization histories suggested by the chemical, crystallographic, morphological, and paragenetic relationships observed in pyroxenes from basalts collected on the Apollo 11, 12, 14, 15, and Luna 16 missions. Although the final stages of lunar basalt crystallization appear to be rapid near-surface events, the initial stages are shown to vary considerably among the different basalt types.

Experimental Analysis of Small-Group Performance Effectiveness: Behavioral and Biological Interactions.

DTIC Science & Technology

1982-04-01

processes requiring systematic experimental analysis. Accordingly, group performance effectiveness studies were initiated to 61 assess the effects on...the experiment. 67 active processes associated with Joining the respective established groups, but the absence of baseline levels precludes such an...novitiate in comparison to such values observed during baseline days suggested an active process associated with the joining of the group and emphasized the

Maximum magnitude estimations of induced earthquakes at Paradox Valley, Colorado, from cumulative injection volume and geometry of seismicity clusters

NASA Astrophysics Data System (ADS)

Yeck, William L.; Block, Lisa V.; Wood, Christopher K.; King, Vanessa M.

2015-01-01

The Paradox Valley Unit (PVU), a salinity control project in southwest Colorado, disposes of brine in a single deep injection well. Since the initiation of injection at the PVU in 1991, earthquakes have been repeatedly induced. PVU closely monitors all seismicity in the Paradox Valley region with a dense surface seismic network. A key factor for understanding the seismic hazard from PVU injection is the maximum magnitude earthquake that can be induced. The estimate of maximum magnitude of induced earthquakes is difficult to constrain as, unlike naturally occurring earthquakes, the maximum magnitude of induced earthquakes changes over time and is affected by injection parameters. We investigate temporal variations in maximum magnitudes of induced earthquakes at the PVU using two methods. First, we consider the relationship between the total cumulative injected volume and the history of observed largest earthquakes at the PVU. Second, we explore the relationship between maximum magnitude and the geometry of individual seismicity clusters. Under the assumptions that: (i) elevated pore pressures must be distributed over an entire fault surface to initiate rupture and (ii) the location of induced events delineates volumes of sufficiently high pore-pressure to induce rupture, we calculate the largest allowable vertical penny-shaped faults, and investigate the potential earthquake magnitudes represented by their rupture. Results from both the injection volume and geometrical methods suggest that the PVU has the potential to induce events up to roughly MW 5 in the region directly surrounding the well; however, the largest observed earthquake to date has been about a magnitude unit smaller than this predicted maximum. In the seismicity cluster surrounding the injection well, the maximum potential earthquake size estimated by these methods and the observed maximum magnitudes have remained steady since the mid-2000s. These observations suggest that either these methods overpredict maximum magnitude for this area or that long time delays are required for sufficient pore-pressure diffusion to occur to cause rupture along an entire fault segment. We note that earthquake clusters can initiate and grow rapidly over the course of 1 or 2 yr, thus making it difficult to predict maximum earthquake magnitudes far into the future. The abrupt onset of seismicity with injection indicates that pore-pressure increases near the well have been sufficient to trigger earthquakes under pre-existing tectonic stresses. However, we do not observe remote triggering from large teleseismic earthquakes, which suggests that the stress perturbations generated from those events are too small to trigger rupture, even with the increased pore pressures.

Return Current Electron Beams and Their Generation of "Raman" Scattering

NASA Astrophysics Data System (ADS)

Simon, A.

1998-11-01

For some years, we(A. Simon and R. W. Short, Phys. Rev. Lett. 53), 1912 (1984). have proposed that the only reasonable explanation for many of the observations of "Raman" scattering is the presence of an electron beam in the plasma. (The beam creates a bump-on-tail instability.) Two major objections to this picture have been observation of Raman when no n_c/4 surface was present, with no likely source for the electron beam, and the necessity for the initially outward directed beam to bounce once to create the proper waves. Now new observations on LLE's OMEGA(R. Petrasso et al), this conference. and at LULI(C. Labaune et al)., Phys. Plasma 5, 234 (1998). have suggested a new origin for the electron beam. This new scenario answers the previous objections, maintains electron beams as the explanation of the older experiments, and may clear up puzzling observations that have remained unexplained. The new scenario is based on two assumptions: (1) High positive potentials develop in target plasmas during their creation. (2) A high-intensity laser beam initiates spark discharges from nearby surfaces to the target plasma. The resulting return current of electrons should be much more delta-like, is initially inwardly directed, and no longer requires the continued presence of a n_c/4 surface. Scattering of the interaction beam from the BOT waves yields the observed Raman signal. Experimental observations that support this picture will be cited. ``Pulsation'' of the scattering and broadband ``flashes'' are a natural part of this scenario. This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC03-92SF19460.

The crustal structure of the Enderby Basin, East Antarctica

NASA Astrophysics Data System (ADS)

Davis, Joshua K.; Lawver, Lawrence A.; Norton, Ian O.; Dalziel, Ian W. D.; Gahagan, Lisa M.

2018-05-01

The passive margin and ocean crust of the Enderby Basin, East Antarctica preserves a record of the breakup of East Gondwana. Using a suite of public domain geophysical data, we have examined and described the crustal morphology of the basin. Based on our geophysical observations, we divide the Enderby Basin into three distinct morphologic domains. The Eastern Domain demonstrates the most volcanic morphology of the basin, with abundant seaward dipping reflector packages and anomalously thick oceanic crust. These features suggest an early influence by the Kerguelen Hotspot on continental breakup within the domain. The Central Domain is characterized by two regions of oceanic crust of varying morphology segregated by a high amplitude magnetic anomaly. Geophysical observations suggest that the basement directly inboard of this magnetic anomaly is composed of thin, rugged, and poorly structured, proto-oceanic crust, similar in morphology to oceanic crust formed at ultraslow/slow mid-ocean ridged. Outboard of this anomaly, oceanic crust appears to be well-structured and of normal thickness. We offer three, non-exclusive, explanations for the observed change in ocean crustal structure: (1) melt production was initially low at the time of continental breakup, and the progressive decompression of the mantle led to a gradual increase in melt production and ocean crust thickness, (2) melt production was initially low to due lower extension rates and that melt production increased following a change in spreading rate, (3) a change in spreading ridge geometry led to more effective seafloor spreading rate and concurrent increase in melt production. The Western Domain of the Enderby Basin is characterized by abundant fracture zones and anomalously thin oceanic crust. We believe these features arose as a geometric consequence of the originally oblique orientation of continental rifting relative to the extension direction within the domain. Together these observations suggest that the breakup of East Gondwana was highly variable, with notable along-strike differences in crustal deformation and seafloor spreading processes.

Initial formation of calcite crystals in the thin prismatic layer with the periostracum of Pinctada fucata.

PubMed

Suzuki, Michio; Nakayama, Seiji; Nagasawa, Hiromichi; Kogure, Toshihiro

2013-02-01

Although the formation mechanism of calcite crystals in the prismatic layer has been studied well in many previous works, the initial state of calcite formation has not been observed in detail using electron microscopes. In this study, we report that the soft prismatic layer with transparent color (the thin prismatic layer) in the tip of the fresh shell of Pinctada fucata was picked up to observe the early calcification phase. A scanning electron microscope (SEM) image showed that the growth tip of the thin prismatic layer was covered by the periostracum, which was also where the initial formation of calcite crystals began. A cross-section containing the thin calcite crystals in the thin prismatic layer with the periostracum was made using a focused ion beam (FIB) system. In a transmission electron microscope (TEM) observation, the thin calcite crystal (thickness is about 1μm) on the periostracum was found to be a single crystal with the c-axis oriented perpendicular to the shell surface. On the other hand, many aggregated small particles consisting of bassanite crystals were observed in the periostracum suggesting the possibility that not only organic sulfate but also inorganic sulfates exist in the prismatic layer. These discoveries in the early calcification phase of the thin prismatic layer may help to clarify the mechanism of regulating the nucleation and orientation of the calcite crystal in the shell. Copyright © 2012 Elsevier Ltd. All rights reserved.

Long-term adaptation to change in implicit contextual learning.

PubMed

Zellin, Martina; von Mühlenen, Adrian; Müller, Hermann J; Conci, Markus

2014-08-01

The visual world consists of spatial regularities that are acquired through experience in order to guide attentional orienting. For instance, in visual search, detection of a target is faster when a layout of nontarget items is encountered repeatedly, suggesting that learned contextual associations can guide attention (contextual cuing). However, scene layouts sometimes change, requiring observers to adapt previous memory representations. Here, we investigated the long-term dynamics of contextual adaptation after a permanent change of the target location. We observed fast and reliable learning of initial context-target associations after just three repetitions. However, adaptation of acquired contextual representations to relocated targets was slow and effortful, requiring 3 days of training with overall 80 repetitions. A final test 1 week later revealed equivalent effects of contextual cuing for both target locations, and these were comparable to the effects observed on day 1. That is, observers learned both initial target locations and relocated targets, given extensive training combined with extended periods of consolidation. Thus, while implicit contextual learning efficiently extracts statistical regularities of our environment at first, it is rather insensitive to change in the longer term, especially when subtle changes in context-target associations need to be acquired.

Grammar Predicts Procedural Learning and Consolidation Deficits in Children with Specific Language Impairment

PubMed Central

Hedenius, Martina; Persson, Jonas; Tremblay, Antoine; Adi-Japha, Esther; Veríssimo, João; Dye, Cristina D.; Alm, Per; Jennische, Margareta; Tomblin, J. Bruce; Ullman, Michael T.

2011-01-01

The Procedural Deficit Hypothesis (PDH) posits that Specific Language Impairment (SLI) can be largely explained by abnormalities of brain structures that subserve procedural memory. The PDH predicts impairments of procedural memory itself, and that such impairments underlie the grammatical deficits observed in the disorder. Previous studies have indeed reported procedural learning impairments in SLI, and have found that these are associated with grammatical difficulties. The present study extends this research by examining the consolidation and longer-term procedural sequence learning in children with SLI. The Alternating Serial Reaction Time (ASRT) task was given to children with SLI and typically-developing (TD) children in an initial learning session and an average of three days later to test for consolidation and longer-term learning. Although both groups showed evidence of initial sequence learning, only the TD children showed clear signs of consolidation, even though the two groups did not differ in longer-term learning. When the children were re-categorized on the basis of grammar deficits rather than broader language deficits, a clearer pattern emerged. Whereas both the grammar impaired and normal grammar groups showed evidence of initial sequence learning, only those with normal grammar showed consolidation and longer-term learning. Indeed, the grammar-impaired group appeared to lose any sequence knowledge gained during the initial testing session. These findings held even when controlling for vocabulary or a broad non-grammatical language measure, neither of which were associated with procedural memory. When grammar was examined as a continuous variable over all children, the same relationships between procedural memory and grammar, but not vocabulary or the broader language measure, were observed. Overall, the findings support and further specify the PDH. They suggest that consolidation and longer-term procedural learning are impaired in SLI, but that these impairments are specifically tied to the grammatical deficits in the disorder. The possibility that consolidation and longer-term learning are problematic in the disorder suggests a locus of potential study for therapeutic approaches. In sum, this study clarifies our understanding of the underlying deficits in SLI, and suggests avenues for further research. PMID:21840165

Thermal Effects for Quark and Gluon Distributions in Heavy-Ion Collisions at Nica

NASA Astrophysics Data System (ADS)

Lykasov, G. I.; Sissakian, A. N.; Sorin, A. S.; Teryaev, O. V.

2011-10-01

In-medium effects for distributions of quarks and gluons in central A+A collisions are considered. We suggest a duality principle, which means similarity of thermal spectra of hadrons produced in heavy-ion collisions and inclusive spectra which can be obtained within the dynamic quantum scattering theory. Within the suggested approach we show that the mean square of the transverse momentum for these partons grows and then saturates when the initial energy increases. It leads to the energy dependence of hadron transverse mass spectra which is similar to that observed in heavy ion collisions.

Initial Dynamical Evolution of Star Clusters with Tidal Field

NASA Astrophysics Data System (ADS)

Park, So-Myoung; Goodwin, Simon P.; Kim, Sungsoo S.

2017-03-01

Observations have been suggested that star clusters could form from the rapid collapse and violent relaxation of substructured distributions. We investigate the collapse of fractal stellar distributions in no, weak, and very strong tidal fields. We find that the rapid collapse of substructure into spherical clusters happens quickly with no or a weak tidal field, but very strong tidal fields prevent a cluster forming. However, we also find that dense Plummer spheres are also rapidly destroyed in strong tidal fields. We suggest that this is why the low-mass star clusters cannot survive near the galactic centre which has strong tidal field.

A snap shot of the short-term response of crustaceans to macrophyte detritus in the deep Oslofjord.

PubMed

Ramirez-Llodra, Eva; Rinde, Eli; Gundersen, Hege; Christie, Hartvig; Fagerli, Camilla With; Fredriksen, Stein; Gitmark, Janne Kim; Norling, Karl; Walday, Mats Gunnar; Norderhaug, Kjell Magnus

2016-03-30

A test deployment of a time-lapse camera lander in the deep Oslofjord (431 m) was used to obtain initial information on the response of benthic fauna to macroalgal debris. Three macroalgal species were used on the lander baited plate: Fucus serratus, Saccharina latissima and Laminaria hyperborea and observed during 41.5 hours. The deep-water shrimp Pandalus borealis were attracted to the macroalgae rapidly (3 min after the lander reached the seafloor), followed by amphipods. Shrimp abundances were significantly higher in areas covered by macroalgae compared to the adjacent seafloor and the number of shrimp visiting the macroalgae increased with time. Amphipods arrived 13 hours later and were observed mainly on decaying L. hyperborea. The abundance of amphipods on L. hyperborea increased rapidly, reaching a peak at 31 h after deployment. These initial observations suggest that debris from kelp forests and other macroalgal beds may play an important role in fuelling deep benthic communities in the outer Oslofjord and, potentially, enhance secondary production of commercial species such as P. borealis.

Extracting Information about the Initial State from the Black Hole Radiation.

PubMed

Lochan, Kinjalk; Padmanabhan, T

2016-02-05

The crux of the black hole information paradox is related to the fact that the complete information about the initial state of a quantum field in a collapsing spacetime is not available to future asymptotic observers, belying the expectations from a unitary quantum theory. We study the imprints of the initial quantum state contained in a specific class of distortions of the black hole radiation and identify the classes of in states that can be partially or fully reconstructed from the information contained within. Even for the general in state, we can uncover some specific information. These results suggest that a classical collapse scenario ignores this richness of information in the resulting spectrum and a consistent quantum treatment of the entire collapse process might allow us to retrieve much more information from the spectrum of the final radiation.

Revisiting the false alarm in the 2014 El Niño prediction

NASA Astrophysics Data System (ADS)

Shin, C. S.; Huang, B.

2016-12-01

In early 2014, most dynamic forecast models predicted a developing strong El Niño in the following winter. However, this forecast turned out to be a representative case of the false alarms since 2000. In this study, a set of CFSv2 ensemble seasonal reforecast is conducted to examine some possible causes of the unrealistic El Niño prediction in 2014. Zooming in on the NINO3.4 index, the ensemble-mean reforecast initialized in April 2014 predicted a very strong El Niño as the 1997-98 one with most ensemble members warmer than the observations. In contrast, the ensemble-mean reforecast initialized in January (July) 2014 predicted a slower growth (a decline) of the NINO3.4 index for 12-month lead (from November to the spring in 2015), with the spreads of the ensemble members enveloping the observations. Since the observed SST anomalies in equatorial eastern Pacific changed its polarity in late March from the coldest SST anomalies in February accompanied by strong easterly wind to warmer SST in mid April, the atmospheric and oceanic instantaneous initial states in early April 2014 may misrepresent these intra-seasonal variations, possibly resulting in warm bias in equatorial Pacific even at 0-month lead. Our experiments show that colder ocean surface initial conditions in tropical eastern Pacific tend to hinder developing warm SST anomalies in equatorial eastern Pacific and weaken the Bjerknes-type air-sea feedback in the summer of 2014, which reduce excessive westerly wind (warm SST anomalies) in equatorial western Pacific (near the Dateline) and decrease the air-sea feedback. As a result, the predicted amplitude of NINO3.4 at the peak phase is comparable to the observed one, suggesting that the initial condition errors are partially responsible for the false alarm in the 2014 El Niño prediction issued in the spring. Nonetheless, the initial condition errors could not account for easterly wind burst observed in mid June associated with enhanced extratropical anti-cyclonic atmospheric circulation anomalies in the Southern Hemisphere, which is regarded as another major factor to stall the El Niño occurrence in 2014. What drives this anomalous atmospheric forcing in mid June and how much it contributes to a more realistic prediction of the 2014 El Niño will also be discussed.

Lidar ceilometer observations and modeling of a fireworks plume in Vancouver, British Columbia

NASA Astrophysics Data System (ADS)

van der Kamp, Derek; McKendry, Ian; Wong, May; Stull, Roland

Observations of a plume emanating from a 30-min duration pyrotechnic display with a lidar ceilometer are described for an urban setting in complex, coastal terrain. Advection of the plume across the ceilometer occurred at a mean height of 250 m AGL. The plume traveled downwind at ˜3 m s -1, and at a distance of 8 km downwind, was ˜100 m in vertical thickness with particulate matter (PM) concentrations of order 30-40 μg m -3. Surface PM observations from surrounding urban monitoring stations suggest that the plume was not mixed to ground over the urban area. Plume trajectories at ˜250 m simulated by three numerical models all traveled to the northeast of the ceilometer location. Horizontal plume dispersion estimates suggest that the model trajectories were too far north to accommodate the likely lateral plume spread necessary to explain the ceilometer observations. This poor agreement between near surface observations and model output is consistent with previous mesoscale model validations in this region of complex urbanized terrain, and suggests that despite improvements in mesoscale model resolution, there remains an urgent need to improve upstream initial conditions over the Pacific Ocean, data assimilation over complex terrain, the representation of urban areas in mesoscale models, and to further validate such models for nocturnal applications in complex settings.

Management of minor head injury in patients receiving oral anticoagulant therapy: a prospective study of a 24-hour observation protocol.

PubMed

Menditto, Vincenzo G; Lucci, Moira; Polonara, Stefano; Pomponio, Giovanni; Gabrielli, Armando

2012-06-01

Patients receiving warfarin who experience minor head injury are at risk of intracranial hemorrhage, and optimal management after a single head computed tomography (CT) scan is unclear. We evaluate a protocol of 24-hour observation followed by a second head CT scan. In this prospective case series, we enrolled consecutive patients receiving warfarin and showing no intracranial lesions on a first CT scan after minor head injury treated at a Level II trauma center. We implemented a structured clinical pathway, including 24-hour observation and a CT scan performed before discharge. We then evaluated the frequency of death, admission, neurosurgery, and delayed intracranial hemorrhage. We enrolled and observed 97 consecutive patients. Ten refused the second CT scan and were well during 30-day follow-up. Repeated CT scanning in the remaining 87 patients revealed a new hemorrhage lesion in 5 (6%), with 3 subsequently hospitalized and 1 receiving craniotomy. Two patients discharged after completing the study protocol with 2 negative CT scan results were admitted 2 and 8 days later with symptomatic subdural hematomas; neither received surgery. Two of the 5 patients with delayed bleeding at 24 hours had an initial international normalized ratio greater than 3.0, as did both patients with delayed bleeding beyond 24 hours. The relative risk of delayed hemorrhage with an initial international normalized ratio greater than 3.0 was 14 (95% confidence interval 4 to 49). For patients receiving warfarin who experience minor head injury and have a negative initial head CT scan result, a protocol of 24-hour observation followed by a second CT scan will identify most occurrences of delayed bleeding. An initial international normalized ratio greater than 3 suggests higher risk. Copyright © 2011 American College of Emergency Physicians. Published by Mosby, Inc. All rights reserved.

Inhomogeneity of the ultrafast insulator-to-metal transition dynamics of VO2.

PubMed

O'Callahan, Brian T; Jones, Andrew C; Hyung Park, Jae; Cobden, David H; Atkin, Joanna M; Raschke, Markus B

2015-04-21

The insulator-metal transition (IMT) of vanadium dioxide (VO2) has remained a long-standing challenge in correlated electron physics since its discovery five decades ago. Most interpretations of experimental observations have implicitly assumed a homogeneous material response. Here we reveal inhomogeneous behaviour of even individual VO2 microcrystals using pump-probe microscopy and nanoimaging. The timescales of the ultrafast IMT vary from 40±8 fs, that is, shorter than a suggested phonon bottleneck, to 200±20 fs, uncorrelated with crystal size, transition temperature and initial insulating structural phase, with average value similar to results from polycrystalline thin-film studies. In combination with the observed sensitive variations in the thermal nanodomain IMT behaviour, this suggests that the IMT is highly susceptible to local changes in, for example, doping, defects and strain. Our results suggest an electronic mechanism dominating the photoinduced IMT, but also highlight the difficulty to deduce microscopic mechanisms when the true intrinsic material response is yet unclear.

Experimental evaluation of rigor mortis. VIII. Estimation of time since death by repeated measurements of the intensity of rigor mortis on rats.

PubMed

Krompecher, T

1994-10-21

The development of the intensity of rigor mortis was monitored in nine groups of rats. The measurements were initiated after 2, 4, 5, 6, 8, 12, 15, 24, and 48 h post mortem (p.m.) and lasted 5-9 h, which ideally should correspond to the usual procedure after the discovery of a corpse. The experiments were carried out at an ambient temperature of 24 degrees C. Measurements initiated early after death resulted in curves with a rising portion, a plateau, and a descending slope. Delaying the initial measurement translated into shorter rising portions, and curves initiated 8 h p.m. or later are comprised of a plateau and/or a downward slope only. Three different phases were observed suggesting simple rules that can help estimate the time since death: (1) if an increase in intensity was found, the initial measurements were conducted not later than 5 h p.m.; (2) if only a decrease in intensity was observed, the initial measurements were conducted not earlier than 7 h p.m.; and (3) at 24 h p.m., the resolution is complete, and no further changes in intensity should occur. Our results clearly demonstrate that repeated measurements of the intensity of rigor mortis allow a more accurate estimation of the time since death of the experimental animals than the single measurement method used earlier. A critical review of the literature on the estimation of time since death on the basis of objective measurements of the intensity of rigor mortis is also presented.

Bioleaching of arsenic from highly contaminated mine tailings using Acidithiobacillus thiooxidans.

PubMed

Lee, Eunseong; Han, Yosep; Park, Jeonghyun; Hong, Jeongsik; Silva, Rene A; Kim, Seungkon; Kim, Hyunjung

2015-01-01

The behavior of arsenic (As) bioleaching from mine tailings containing high amount of As (ca. 34,000 mg/kg) was investigated using Acidithiobacillus thiooxidans to get an insight on the optimal conditions that would be applied to practical heap and/or tank bioleaching tests. Initial pH (1.8-2.2), temperature (25-40 °C), and solid concentration (0.5-4.0%) were employed as experimental parameters. Complementary characterization experiments (e.g., XRD, SEM-EDS, electrophoretic mobility, cell density, and sulfate production) were also carried out to better understand the mechanism of As bioleaching. The results showed that final As leaching efficiency was similar regardless of initial pH. However, greater initial As leaching rate was observed at initial pH 1.8 than other conditions, which could be attributed to greater initial cell attachment to mine tailings. Unlike the trend observed when varying the initial pH, the final As leaching efficiency varied with the changes in temperature and solid concentration. Specifically, As leaching efficiency tended to decrease with increasing temperature due to the decrease in the bacterial growth rate at higher temperature. Meanwhile, As leaching efficiency tended to increase with decreasing solid concentration. The results for jarosite contents in mine tailings residue after bioleaching revealed that much greater amount of the jarosite was formed during the bioleaching reaction at higher solid concentration, suggesting that the coverage of the surface of the mine tailings by jarosite and/or the co-precipitation of the leached As with jarosite could be a dominant factor reducing As leaching efficiency. Copyright © 2014 Elsevier Ltd. All rights reserved.

The Contribution of Soil Moisture Information to Forecast Skill: Two Studies

NASA Technical Reports Server (NTRS)

Koster, Randal

2010-01-01

This talk briefly describes two recent studies on the impact of soil moisture information on hydrological and meteorological prediction. While the studies utilize soil moisture derived from the integration of large-scale land surface models with observations-based meteorological data, the results directly illustrate the potential usefulness of satellite-derived soil moisture information (e.g., from SMOS and SMAP) for applications in prediction. The first study, the GEWEX- and ClIVAR-sponsored GLACE-2 project, quantifies the contribution of realistic soil moisture initialization to skill in subseasonal forecasts of precipitation and air temperature (out to two months). The multi-model study shows that soil moisture information does indeed contribute skill to the forecasts, particularly for air temperature, and particularly when the initial local soil moisture anomaly is large. Furthermore, the skill contributions tend to be larger where the soil moisture initialization is more accurate, as measured by the density of the observational network contributing to the initialization. The second study focuses on streamflow prediction. The relative contributions of snow and soil moisture initialization to skill in streamflow prediction at seasonal lead, in the absence of knowledge of meteorological anomalies during the forecast period, were quantified with several land surface models using uniquely designed numerical experiments and naturalized streamflow data covering mUltiple decades over the western United States. In several basins, accurate soil moisture initialization is found to contribute significant levels of predictive skill. Depending on the date of forecast issue, the contributions can be significant out to leads of six months. Both studies suggest that improvements in soil moisture initialization would lead to increases in predictive skill. The relevance of SMOS and SMAP satellite-based soil moisture information to prediction are discussed in the context of these studies.

Impact of body weight on virological and immunological responses to efavirenz-containing regimens in HIV-infected, treatment-naive adults.

PubMed

Marzolini, Catia; Sabin, Caroline; Raffi, François; Siccardi, Marco; Mussini, Cristina; Launay, Odile; Burger, David; Roca, Bernardino; Fehr, Jan; Bonora, Stefano; Mocroft, Amanda; Obel, Niels; Dauchy, Frederic-Antoine; Zangerle, Robert; Gogos, Charalambos; Gianotti, Nicola; Ammassari, Adriana; Torti, Carlo; Ghosn, Jade; Chêne, Genevieve; Grarup, Jesper; Battegay, Manuel

2015-01-14

The prevalence of overweight and obesity is increasing among HIV-infected patients. Whether standard antiretroviral drug dosage is adequate in heavy individuals remains unresolved. We assessed the virological and immunological responses to initial efavirenz (EFV)-containing regimens in heavy compared to normal-weight HIV-infected patients. Observational European cohort collaboration study. Eligible patients were antiretroviral-naïve with documented weight prior to EFV start and follow-up viral loads after treatment initiation. Cox regression analyses evaluated the association between weight and time to first undetectable viral load (<50 copies/ml) after treatment initiation, and time to viral load rebound (two consecutive viral load >50 copies/ml) after initial suppression over 5 years of follow-up. Recovery of CD4 cell count was evaluated 6 and 12 months after EFV initiation. Analyses were stratified by weight (kg) group (I - <55; II - >55, <80 (reference); III - >80, <85; IV - >85, <90; V - >90, <95; VI - >95). The study included 19,968 patients, of whom 9.1, 68.3, 9.1, 5.8, 3.5, and 4.3% were in weight groups I-VI, respectively. Overall, 81.1% patients attained virological suppression, of whom 34.1% subsequently experienced viral load rebound. After multiple adjustments, no statistical difference was observed in time to undetectable viral load and virological rebound for heavier individuals compared to their normal-weight counterparts. Although heaviest individuals had significantly higher CD4 cell count at baseline, CD4 cell recovery at 6 and 12 months after EFV initiation was comparable to normal-weight individuals. Virological and immunological responses to initial EFV-containing regimens were not impaired in heavy individuals, suggesting that the standard 600 mg EFV dosage is appropriate across a wide weight range.

Diary of events in a thoroughly unhaunted house.

PubMed

Houran, J; Lange, R

1996-10-01

Two subjects were asked to keep a 30-day journal of occurrences in their residence which are traditionally associated with hauntings and poltergeist-like phenomena. It was expected that the instructions would increase the frequency of perception of unusual or rarely occurring events in their residence, resulting in an attentional and "perceptual contagion effect." As expected, several features of the percipients' observations closely resembled those found in previously reported poltergeist episodes. Most importantly, the distribution of perceived occurrences closely resembled the predicted logistic curve, suggesting that hauntings involve a perceptual process where initial observations "infect" later ones.

Detection of water vapor on Jupiter

NASA Technical Reports Server (NTRS)

Larson, H. P.; Fink, U.; Treffers, R.; Gautier, T. N., III

1975-01-01

High-altitude (12.4 km) spectroscopic observations of Jupiter at 5 microns from the NASA 91.5 cm airborne infrared telescope have revealed 14 absorptions assigned to the rotation-vibration spectrum of water vapor. Preliminary analysis indicates a mixing ratio about 1 millionth for the vapor phase of water. Estimates of temperature (greater than about 300 K) and pressure (less than 20 atm) suggest observation of water deep in Jupiter's hot spots responsible for its 5 micron flux. Model-atmosphere calculations based on radiative-transfer theory may change these initial estimates and provide a better physical picture of Jupiter's atmosphere below the visible cloud tops.

Anismus as a marker of sexual abuse. Consequences of abuse on anorectal motility.

PubMed

Leroi, A M; Berkelmans, I; Denis, P; Hémond, M; Devroede, G

1995-07-01

Anorectal manometry was performed in 40 women, who consulted for functional disorders of the lower gastrointestinal tract and had been sexually abused. Anismus, defined as a rise in anal pressure during straining, was observed in 39 of 40 abused women, but in only six of 20 healthy control women (P < 0.0001). Other parameters of anorectal manometry were compared with those observed in another control group composed of 31 nonabused women but with anismus, as well as the group of healthy controls. A decreased amplitude of anal voluntary contraction and an increased threshold volume in perception of rectal distension were observed in both abused and nonabused patients. A decreased amplitude of rectoanal inhibitory reflex, little rise in rectal pressure upon straining, frequent absence of initial contraction during rectal distension, and increased resting pressure at the lower part of the anal canal were observed in abused but not in nonabused patients, suggesting that these abnormalities, in association with anismus, suggest a pattern of motor activity in the anal canal that could be indicative of sexual abuse.

Initiation and slow propagation of epileptiform activity from ventral to dorsal medial entorhinal cortex is constrained by an inhibitory gradient.

PubMed

Ridler, Thomas; Matthews, Peter; Phillips, Keith G; Randall, Andrew D; Brown, Jonathan T

2018-06-01

The medial entorhinal cortex (mEC) has an important role in initiation and propagation of seizure activity. Several anatomical relationships exist in neurophysiological properties of mEC neurons; however, in the context of hyperexcitability, previous studies often considered it as a homogeneous structure. Using multi-site extracellular recording techniques, ictal-like activity was observed along the dorso-ventral axis of the mEC in vitro in response to various ictogenic stimuli. This originated predominantly from ventral areas, spreading to dorsal mEC with a surprisingly slow velocity. Modulation of inhibitory tone was capable of changing the slope of ictal initiation, suggesting seizure propagation behaviours are highly dependent on levels of GABAergic function in this region. A distinct disinhibition model also showed, in the absence of inhibition, a prevalence for interictal-like initiation in ventral mEC, reflecting the intrinsic differences in mEC neurons. These findings suggest the ventral mEC is more prone to hyperexcitable discharge than the dorsal mEC, which may be relevant under pathological conditions. The medial entorhinal cortex (mEC) has an important role in the generation and propagation of seizure activity. The organization of the mEC is such that a number of dorso-ventral relationships exist in neurophysiological properties of neurons. These range from intrinsic and synaptic properties to density of inhibitory connectivity. We examined the influence of these gradients on generation and propagation of epileptiform activity in the mEC. Using a 16-shank silicon probe array to record along the dorso-ventral axis of the mEC in vitro, we found 4-aminopyridine application produces ictal-like activity originating predominantly in ventral areas. This activity spreads to dorsal mEC at a surprisingly slow velocity (138 μm s -1 ), while cross-site interictal-like activity appeared relatively synchronous. We propose that ictal propagation is constrained by differential levels of GABAergic control since increasing (diazepam) or decreasing (Ro19-4603) GABA A receptor activation, respectively, reduced or increased the slope of ictal initiation. The observation that ictal activity is predominately generated in ventral mEC was replicated using a separate 0-Mg 2+ model of epileptiform activity in vitro. By using a distinct disinhibition model (co-application of kainate and picrotoxin) we show that additional physiological features (for example intrinsic properties of mEC neurons) still produce a prevalence for interictal-like initiation in ventral mEC. These findings suggest that the ventral mEC is more likely to initiate hyperexcitable discharges than the dorsal mEC, and that seizure propagation is highly dependent on levels of GABAergic expression across the mEC. © 2018 The Authors. The Journal of Physiology © 2018 The Physiological Society.

Quality of life before hyperhidrosis treatment as a predictive factor for oxybutynin treatment outcomes in palmar and axillary hyperhidrosis.

PubMed

Wolosker, Nelson; Krutman, Mariana; Teivelis, Marcelo P; Campbell, Taiz P D A; Kauffman, Paulo; de Campos, José Ribas M; Puech-Leão, Pedro

2014-05-01

Studies have suggested that quality of life (QOL) evaluation before video-assisted thoracoscopic sympathectomy for patients with hyperhidrosis may serve as a predictive factor for positive postoperative outcomes. Our study aims to analyze if this tendency is also observed in patients treated with oxybutynin for palmar and axillary hyperhidrosis. Five hundred sixty-five patients who submitted to a protocol treatment with oxybutynin were retrospectively analyzed between January 2007 and January 2012 and were divided into 2 groups according to QOL assessment before treatment. The groups consisted of 176 patients with "poor" and 389 patients with "very poor" QOL evaluation before oxybutynin treatment. Outcomes involving improvements in QOL and clinical progression of hyperhidrosis were evaluated using a validated clinical questionnaire that was specifically designed to assess satisfaction in patients with excessive sweating. Improvements in hyperhidrosis after oxybutynin were observed in 65.5% of patients with very poor pretreatment QOL scores and in 75% of patients with poor pretreatment QOL scores, and the only adverse event associated with oxybutynin treatment was dry mouth, which was observed with greater intensity in patients with very poor initial QOL evaluation. Improvements in hyperhidrosis after oxybutynin treatment were similar in both groups, suggesting that QOL before treatment is not a predictive factor for clinical outcomes, contrasting with surgical results that disclose significantly better results in patients with initially poorer QOL analysis. Copyright © 2014 Elsevier Inc. All rights reserved.

Effect of routine repeat transurethral resection for superficial bladder cancer: a long-term observational study.

PubMed

Grimm, Marc-Oliver; Steinhoff, Christine; Simon, Xenia; Spiegelhalder, Philipp; Ackermann, Rolf; Vogeli, Thomas Alexander

2003-08-01

We determined the long-term outcome in patients with superficial bladder cancer (Ta and T1) undergoing routine second transurethral bladder tumor resection (ReTURB) in regard to recurrence and progression. We performed an inception cohort study of 124 consecutive patients with superficial bladder cancer undergoing transurethral resection and routine ReTURB (83) between November 1993 and October 1995 at a German university hospital. Immediately after transurethral resection all lesions were documented on a designed bladder map. ReTURB of the scar from initial resection and other suspicious lesions was performed at a mean of 7 weeks. Patients were followed until recurrence or death, or a minimum of 5 years. Residual tumor was found in 33% of all ReTURB cases, including 27% of Ta and 53% of T1 disease, and in 81% at the initial resection site. Five of the 83 patients underwent radical cystectomy due to ReTURB findings. The estimated risk of recurrence after years 1 to 3 was 18%, 29% and 32%, respectively. After 5 years 63% of the patients undergoing ReTURB were still disease-free (mean recurrence-free survival 62 months, median 87). Progression to muscle invasive disease was observed in only 2 patients (3%) after a mean observation of 61 months. These data suggest a favorable outcome regarding recurrence and progression in patients with superficial bladder cancer who undergo ReTURB. ReTURB is suggested at least in those at high risk when bladder preservation is intended.

Fractal analysis of Xylella fastidiosa biofilm formation

NASA Astrophysics Data System (ADS)

Moreau, A. L. D.; Lorite, G. S.; Rodrigues, C. M.; Souza, A. A.; Cotta, M. A.

2009-07-01

We have investigated the growth process of Xylella fastidiosa biofilms inoculated on a glass. The size and the distance between biofilms were analyzed by optical images; a fractal analysis was carried out using scaling concepts and atomic force microscopy images. We observed that different biofilms show similar fractal characteristics, although morphological variations can be identified for different biofilm stages. Two types of structural patterns are suggested from the observed fractal dimensions Df. In the initial and final stages of biofilm formation, Df is 2.73±0.06 and 2.68±0.06, respectively, while in the maturation stage, Df=2.57±0.08. These values suggest that the biofilm growth can be understood as an Eden model in the former case, while diffusion-limited aggregation (DLA) seems to dominate the maturation stage. Changes in the correlation length parallel to the surface were also observed; these results were correlated with the biofilm matrix formation, which can hinder nutrient diffusion and thus create conditions to drive DLA growth.

Population ecology of breeding Pacific common eiders on the Yukon-Kuskokwim Delta, Alaska

USGS Publications Warehouse

Wilson, Heather M.; Flint, Paul L.; Powell, Abby N.; Grand, J. Barry; Moral, Christine L.

2012-01-01

Populations of Pacific common eiders (Somateria mollissima v-nigrum) on the Yukon-Kuskokwim Delta (YKD) in western Alaska declined by 50–90% from 1957 to 1992 and then stabilized at reduced numbers from the early 1990s to the present. We investigated the underlying processes affecting their population dynamics by collection and analysis of demographic data from Pacific common eiders at 3 sites on the YKD (1991–2004) for 29 site-years. We examined variation in components of reproduction, tested hypotheses about the influence of specific ecological factors on life-history variables, and investigated their relative contributions to local population dynamics. Reproductive output was low and variable, both within and among individuals, whereas apparent survival of adult females was high and relatively invariant (0.89 ± 0.005). All reproductive parameters varied across study sites and years. Clutch initiation dates ranged from 4 May to 28 June, with peak (modal) initiation occurring on 26 May. Females at an island study site consistently initiated clutches 3–5 days earlier in each year than those on 2 mainland sites. Population variance in nest initiation date was negatively related to the peak, suggesting increased synchrony in years of delayed initiation. On average, total clutch size (laid) ranged from 4.8 to 6.6 eggs, and declined with date of nest initiation. After accounting for partial predation and non-viability of eggs, average clutch size at hatch ranged from 2.0 to 5.8 eggs. Within seasons, daily survival probability (DSP) of nests was lowest during egg-laying and late-initiation dates. Estimated nest survival varied considerably across sites and years (mean = 0.55, range: 0.06–0.92), but process variance in nest survival was relatively low (0.02, CI: 0.01–0.05), indicating that most variance was likely attributed to sampling error. We found evidence that observer effects may have reduced overall nest survival by 0.0–0.36 across site-years. Study sites with lower sample sizes and more frequent visitations appeared to experience greater observer effects. In general, Pacific common eiders exhibited high spatio-temporal variance in reproductive components. Larger clutch sizes and high nest survival at early initiation dates suggested directional selection favoring early nesting. However, stochastic environmental effects may have precluded response to this apparent selection pressure. Our results suggest that females breeding early in the season have the greatest reproductive value, as these birds lay the largest clutches and have the highest probability of successfully hatching. We developed stochastic, stage-based, matrix population models that incorporated observed spatio-temporal (process) variance and co-variation in vital rates, and projected the stable stage distribution () and population growth rate (λ). We used perturbation analyses to examine the relative influence of changes in vital rates on λ and variance decomposition to assess the proportion of variation in λ explained by process variation in each vital rate. In addition to matrix-based λ, we estimated λ using capture–recapture approaches, and log-linear regression. We found the stable age distribution for Pacific common eiders was weighted heavily towards experienced adult females (≥4 yr of age), and all calculations of λ indicated that the YKD population was stable to slightly increasing (λmatrix = 1.02, CI: 1.00–1.04); λreverse-capture–recapture = 1.05, CI: 0.99–1.11; λlog-linear = 1.04, CI: 0.98–1.10). Perturbation analyses suggested the population would respond most dramatically to changes in adult female survival (relative influence of adult survival was 1.5 times that of fecundity), whereas retrospective variation in λ was primarily explained by fecundity parameters (60%), particularly duckling survival (42%). Among components of fecundity, sensitivities were highest for duckling survival, suggesti

The effect of modeled absolute timing variability and relative timing variability on observational learning.

PubMed

Grierson, Lawrence E M; Roberts, James W; Welsher, Arthur M

2017-05-01

There is much evidence to suggest that skill learning is enhanced by skill observation. Recent research on this phenomenon indicates a benefit of observing variable/erred demonstrations. In this study, we explore whether it is variability within the relative organization or absolute parameterization of a movement that facilitates skill learning through observation. To do so, participants were randomly allocated into groups that observed a model with no variability, absolute timing variability, relative timing variability, or variability in both absolute and relative timing. All participants performed a four-segment movement pattern with specific absolute and relative timing goals prior to and following the observational intervention, as well as in a 24h retention test and transfers tests that featured new relative and absolute timing goals. Absolute timing error indicated that all groups initially acquired the absolute timing, maintained their performance at 24h retention, and exhibited performance deterioration in both transfer tests. Relative timing error revealed that the observation of no variability and relative timing variability produced greater performance at the post-test, 24h retention and relative timing transfer tests, but for the no variability group, deteriorated at absolute timing transfer test. The results suggest that the learning of absolute timing following observation unfolds irrespective of model variability. However, the learning of relative timing benefits from holding the absolute features constant, while the observation of no variability partially fails in transfer. We suggest learning by observing no variability and variable/erred models unfolds via similar neural mechanisms, although the latter benefits from the additional coding of information pertaining to movements that require a correction. Copyright © 2017 Elsevier B.V. All rights reserved.

Virtual water maze learning in human increases functional connectivity between posterior hippocampus and dorsal caudate.

PubMed

Woolley, Daniel G; Mantini, Dante; Coxon, James P; D'Hooge, Rudi; Swinnen, Stephan P; Wenderoth, Nicole

2015-04-01

Recent work has demonstrated that functional connectivity between remote brain regions can be modulated by task learning or the performance of an already well-learned task. Here, we investigated the extent to which initial learning and stable performance of a spatial navigation task modulates functional connectivity between subregions of hippocampus and striatum. Subjects actively navigated through a virtual water maze environment and used visual cues to learn the position of a fixed spatial location. Resting-state functional magnetic resonance imaging scans were collected before and after virtual water maze navigation in two scan sessions conducted 1 week apart, with a behavior-only training session in between. There was a large significant reduction in the time taken to intercept the target location during scan session 1 and a small significant reduction during the behavior-only training session. No further reduction was observed during scan session 2. This indicates that scan session 1 represented initial learning and scan session 2 represented stable performance. We observed an increase in functional connectivity between left posterior hippocampus and left dorsal caudate that was specific to scan session 1. Importantly, the magnitude of the increase in functional connectivity was correlated with offline gains in task performance. Our findings suggest cooperative interaction occurs between posterior hippocampus and dorsal caudate during awake rest following the initial phase of spatial navigation learning. Furthermore, we speculate that the increase in functional connectivity observed during awake rest after initial learning might reflect consolidation-related processing. © 2014 Wiley Periodicals, Inc.

Group therapy as a social context for aphasia recovery: a pilot, observational study in an acute rehabilitation hospital.

PubMed

Fama, Mackenzie E; Baron, Christine R; Hatfield, Brooke; Turkeltaub, Peter E

2016-08-01

Individuals with aphasia often receive therapy from a speech-language pathologist during acute rehabilitation. The literature demonstrates that group-based therapy provides a natural, social environment for language rehabilitation in mild-moderate and/or chronic aphasia; however, the communication of persons with acute, severe non-fluent aphasia during group treatment has not been fully explored. This observational study investigated patient communication during acute rehabilitation. The primary objective was to determine whether participants initiate more communication during group therapy sessions when compared to individual therapy sessions. Ten participants with severe non-fluent aphasia were observed during one individual and one group session during their stay in an acute, inpatient rehabilitation facility. Communicative initiations were tallied and categorized based on type, target, and purpose. Participants initiated communication more often during group sessions than during individual sessions. During groups, participants used more vocalizations and facial expressions to communicate, and the purpose was more often for social closeness than in individual sessions. Participants produced fewer different, real words in group vs. individual sessions, but other measures of communication skill did not differ significantly between the two settings. In the aphasia group treatment described in this study, participants initiated more communication, with greater diversity of expressive modalities and more varied communicative purposes. Participants in group therapy also showed an increased tendency to communicate for the purpose of social closeness. These findings suggest that there are important differences in the communication of patients participating in group vs. individual speech therapy for treatment of acute, severe non-fluent aphasia.

Enhanced seasonal forecast skill following stratospheric sudden warmings

NASA Astrophysics Data System (ADS)

Sigmond, M.; Scinocca, J. F.; Kharin, V. V.; Shepherd, T. G.

2013-02-01

Advances in seasonal forecasting have brought widespread socio-economic benefits. However, seasonal forecast skill in the extratropics is relatively modest, prompting the seasonal forecasting community to search for additional sources of predictability. For over a decade it has been suggested that knowledge of the state of the stratosphere can act as a source of enhanced seasonal predictability; long-lived circulation anomalies in the lower stratosphere that follow stratospheric sudden warmings are associated with circulation anomalies in the troposphere that can last up to two months. Here, we show by performing retrospective ensemble model forecasts that such enhanced predictability can be realized in a dynamical seasonal forecast system with a good representation of the stratosphere. When initialized at the onset date of stratospheric sudden warmings, the model forecasts faithfully reproduce the observed mean tropospheric conditions in the months following the stratospheric sudden warmings. Compared with an equivalent set of forecasts that are not initialized during stratospheric sudden warmings, we document enhanced forecast skill for atmospheric circulation patterns, surface temperatures over northern Russia and eastern Canada and North Atlantic precipitation. We suggest that seasonal forecast systems initialized during stratospheric sudden warmings are likely to yield significantly greater forecast skill in some regions.

Mechanical Flexibility of Zinc Oxide Thin-Film Transistors Prepared by Transfer Printing Method

NASA Astrophysics Data System (ADS)

Eun, K. T.; Hwang, W. J.; Sharma, B. K.; Ahn, J. H.; Lee, Y. K.; Choa, S. H.

In the present study, we demonstrate the performance of Zinc oxide thin film transistors (ZnO TFTs) array subjected to the strain under high bending test and the reliability of TFTs was confirmed for the bending fatigue test of 2000 cycles. Initially, ZnO TFTs were fabricated on Si substrate and subsequently transferred on flexible PET substrate using transfer printing process. It was observed that when the bending radius reached ≥ 11 mm then cracks start to initiate first at SiO2 bridges, acting as interconnecting layers among individual TFT. Whatever the strain is applied to the devices, it is almost equivalently adopted by the SiO2 bridges, as they are relatively weak compared to rest of the part. The initial cracking of destructed SiO2 bridge leads to the secondary cracks to the ITO electrodes upon further increment of bending radius. Numerical simulation suggested that the strain of SiO2 layer reached to fracture level of 0.55% which was concentrated at the edge of SiO2 bridge layer. It also suggests that the round shape of SiO2 bridge can be more fruitful to compensate the stress concentration and to prevent failure of device.

Entrapment of Bacteriocin 105B onto Fabric with Titania

DTIC Science & Technology

2017-02-09

to fabricate a multifunctional textile exhibiting an alternative range of antimicrobial activity from that of nisin, by titania encapsulation of...105b onto fabric. The results of these initial studies suggest that both pure preparations and semi-pure preparations of 105b are active when...encapsulated in titania in solution. However, when the pure preparation of 105b is titania encapsulated on fabric, antimicrobial activity is not observed

Mechanical Properties Versus Morphology of Ordered Polymers. Volume 6

DTIC Science & Technology

1986-06-01

of PBT fiber was examined by TEM of epoxy impregnated fibers. An oriented network of microfibrils with typical fibril diameters of about 80-100A was...observed. We suggest that these microfibrils are the fundamental structural elements of the fiber. Thus knowledge of the mechanism by which this initial...benzobisthiazole) fiber was examined by transmission electron 1 microscopy of epoxy impregnated fibers. An oriented network of microfibrils with typical

Engagement in the HIV Care Continuum among Key Populations in Tijuana, Mexico.

PubMed

Smith, Laramie R; Patterson, Thomas L; Magis-Rodriguez, Carlos; Ojeda, Victoria D; Burgos, Jose Luis; Rojas, Sarah A; Zúñiga, María Luisa; Strathdee, Steffanie A

2016-05-01

In Tijuana, Mexico, HIV is concentrated in sub-epidemics of key populations: persons who inject drugs (PWID), sex workers (SW), and men who have sex with men (MSM). To date, data on engagement in the HIV care continuum among these key populations, particularly in resource-constrained settings, are sparse. We pooled available epidemiological data from six studies (N = 3368) to examine HIV testing and treatment uptake in these key populations; finding an overall HIV prevalence of 5.7 %. Of the 191 identified HIV-positive persons, only 11.5 % knew their HIV-positive status and 3.7 % were on ART. Observed differences between these HIV-positive key populations suggest PWID (vs. non-PWID) were least likely to have previously tested or initiate HIV care. MSM (vs. non-MSM) were more likely to have previously tested but not more likely to know their HIV-positive status. Of persons aware of their HIV-positive status, SW (vs. non-SW) were more likely to initiate HIV care. Findings suggest engagement of key populations in HIV treatment is far below estimates observed for similarly resource-constrained generalized epidemics in sub-Saharan Africa. These data provide one of the first empirical-snapshots highlighting the extent of HIV treatment disparities in key populations.

Brain lactate kinetics: Modeling evidence for neuronal lactate uptake upon activation.

PubMed

Aubert, Agnès; Costalat, Robert; Magistretti, Pierre J; Pellerin, Luc

2005-11-08

A critical issue in brain energy metabolism is whether lactate produced within the brain by astrocytes is taken up and metabolized by neurons upon activation. Although there is ample evidence that neurons can efficiently use lactate as an energy substrate, at least in vitro, few experimental data exist to indicate that it is indeed the case in vivo. To address this question, we used a modeling approach to determine which mechanisms are necessary to explain typical brain lactate kinetics observed upon activation. On the basis of a previously validated model that takes into account the compartmentalization of energy metabolism, we developed a mathematical model of brain lactate kinetics, which was applied to published data describing the changes in extracellular lactate levels upon activation. Results show that the initial dip in the extracellular lactate concentration observed at the onset of stimulation can only be satisfactorily explained by a rapid uptake within an intraparenchymal cellular compartment. In contrast, neither blood flow increase, nor extracellular pH variation can be major causes of the lactate initial dip, whereas tissue lactate diffusion only tends to reduce its amplitude. The kinetic properties of monocarboxylate transporter isoforms strongly suggest that neurons represent the most likely compartment for activation-induced lactate uptake and that neuronal lactate utilization occurring early after activation onset is responsible for the initial dip in brain lactate levels observed in both animals and humans.

The effects of task difficulty on visual search strategy in virtual 3D displays.

PubMed

Pomplun, Marc; Garaas, Tyler W; Carrasco, Marisa

2013-08-28

Analyzing the factors that determine our choice of visual search strategy may shed light on visual behavior in everyday situations. Previous results suggest that increasing task difficulty leads to more systematic search paths. Here we analyze observers' eye movements in an "easy" conjunction search task and a "difficult" shape search task to study visual search strategies in stereoscopic search displays with virtual depth induced by binocular disparity. Standard eye-movement variables, such as fixation duration and initial saccade latency, as well as new measures proposed here, such as saccadic step size, relative saccadic selectivity, and x-y target distance, revealed systematic effects on search dynamics in the horizontal-vertical plane throughout the search process. We found that in the "easy" task, observers start with the processing of display items in the display center immediately after stimulus onset and subsequently move their gaze outwards, guided by extrafoveally perceived stimulus color. In contrast, the "difficult" task induced an initial gaze shift to the upper-left display corner, followed by a systematic left-right and top-down search process. The only consistent depth effect was a trend of initial saccades in the easy task with smallest displays to the items closest to the observer. The results demonstrate the utility of eye-movement analysis for understanding search strategies and provide a first step toward studying search strategies in actual 3D scenarios.

Brain lactate kinetics: Modeling evidence for neuronal lactate uptake upon activation

PubMed Central

Aubert, Agnès; Costalat, Robert; Magistretti, Pierre J.; Pellerin, Luc

2005-01-01

A critical issue in brain energy metabolism is whether lactate produced within the brain by astrocytes is taken up and metabolized by neurons upon activation. Although there is ample evidence that neurons can efficiently use lactate as an energy substrate, at least in vitro, few experimental data exist to indicate that it is indeed the case in vivo. To address this question, we used a modeling approach to determine which mechanisms are necessary to explain typical brain lactate kinetics observed upon activation. On the basis of a previously validated model that takes into account the compartmentalization of energy metabolism, we developed a mathematical model of brain lactate kinetics, which was applied to published data describing the changes in extracellular lactate levels upon activation. Results show that the initial dip in the extracellular lactate concentration observed at the onset of stimulation can only be satisfactorily explained by a rapid uptake within an intraparenchymal cellular compartment. In contrast, neither blood flow increase, nor extracellular pH variation can be major causes of the lactate initial dip, whereas tissue lactate diffusion only tends to reduce its amplitude. The kinetic properties of monocarboxylate transporter isoforms strongly suggest that neurons represent the most likely compartment for activation-induced lactate uptake and that neuronal lactate utilization occurring early after activation onset is responsible for the initial dip in brain lactate levels observed in both animals and humans. PMID:16260743

Unrest episodes at Campi Flegrei: A reconstruction of vertical ground movements during 1905-2009

NASA Astrophysics Data System (ADS)

Del Gaudio, C.; Aquino, I.; Ricciardi, G. P.; Ricco, C.; Scandone, R.

2010-08-01

Geodetic observations at Campi Flegrei caldera were initiated in 1905. Historical observations and the few measurements made before 1970 suggested a deflationary trend. Since 1969, the ground started to inflate during two major uplift episodes in 1969-72 and 1982-1985. We collected and reanalyzed all available punctual observations of vertical ground displacement taken in the period 1905-2009 with special attention to the period before 1969, to reconstruct in greater detail the deformation history of the caldera. We make use of the many photographs of the sea level in a roman ruin (the Serapeum Market) taken during the period between 1905 and 1969 to infer with more accuracy its relative height with respect to the sea level. We identify a previously disregarded major episode of ground uplift occurred between 1950 and 1952 with a maximum uplift of about 73 cm. This finding suggests that Campi Flegrei is currently experiencing a prolonged period of unrest longer than previously thought. The higher seismicity associated with the later episodes of unrest suggests that the volcano has approached an instability threshold, which may eventually result in a volcanic eruption.

Conformational plasticity of RepB, the replication initiator protein of promiscuous streptococcal plasmid pMV158

PubMed Central

Boer, D. Roeland; Ruiz-Masó, José Angel; Rueda, Manuel; Petoukhov, Maxim V.; Machón, Cristina; Svergun, Dmitri I.; Orozco, Modesto; del Solar, Gloria; Coll, Miquel

2016-01-01

DNA replication initiation is a vital and tightly regulated step in all replicons and requires an initiator factor that specifically recognizes the DNA replication origin and starts replication. RepB from the promiscuous streptococcal plasmid pMV158 is a hexameric ring protein evolutionary related to viral initiators. Here we explore the conformational plasticity of the RepB hexamer by i) SAXS, ii) sedimentation experiments, iii) molecular simulations and iv) X-ray crystallography. Combining these techniques, we derive an estimate of the conformational ensemble in solution showing that the C-terminal oligomerisation domains of the protein form a rigid cylindrical scaffold to which the N-terminal DNA-binding/catalytic domains are attached as highly flexible appendages, featuring multiple orientations. In addition, we show that the hinge region connecting both domains plays a pivotal role in the observed plasticity. Sequence comparisons and a literature survey show that this hinge region could exists in other initiators, suggesting that it is a common, crucial structural element for DNA binding and manipulation. PMID:26875695

The mechanism of Fe(2+)-initiated lipid peroxidation in liposomes: the dual function of ferrous ions, the roles of the pre-existing lipid peroxides and the lipid peroxyl radical.

PubMed Central

Tang, L; Zhang, Y; Qian, Z; Shen, X

2000-01-01

The mechanism of Fe(2+)-initiated lipid peroxidation in a liposomal system was studied. It was found that a second addition of ferrous ions within the latent period lengthened the time lag before lipid peroxidation started. The apparent time lag depended on the total dose of Fe(2+) whenever the second dose of Fe(2+) was added, which indicates that Fe(2+) has a dual function: to initiate lipid peroxidation on one hand and suppress the species responsible for the initiation of the peroxidation on the other. When the pre-existing lipid peroxides (LOOH) were removed by incorporating triphenylphosphine into liposomes, Fe(2+) could no longer initiate lipid peroxidation and the acceleration of Fe(2+) oxidation by the liposomes disappeared. However, when extra LOOH were introduced into liposomes, both enhancement of the lipid peroxidation and shortening of the latent period were observed. When the scavenger of lipid peroxyl radicals (LOO(.)), N,N'-diphenyl-p-phenylene-diamine, was incorporated into liposomes, neither initiation of the lipid peroxidation nor acceleration of the Fe(2+) oxidation could be detected. The results may suggest that both the pre-existing LOOH and LOO(.) are necessary for the initiation of lipid peroxidation. The latter comes initially from the decomposition of the pre-existing LOOH by Fe(2+) and can be scavenged by its reaction with Fe(2+). Only when Fe(2+) is oxidized to such a degree that LOO(.) is no longer effectively suppressed does lipid peroxidation start. It seems that by taking the reactions of Fe(2+) with LOOH and LOO(.) into account, the basic chemistry in lipid peroxidation can explain fairly well the controversial phenomena observed in Fe(2+)-initiated lipid peroxidation, such as the existence of a latent period, the critical ratio of Fe(2+) to lipid and the required oxidation of Fe(2+). PMID:11062055

Posture in ovo as a precursor of footedness in ostriches (Struthio camelus).

PubMed

Baciadonna, Luigi; Zucca, Paolo; Tommasi, Luca

2010-01-01

Two categories of behaviour involving lateralized posture were observed in semi-natural conditions in ostriches (Struthio camelus). Observing preferences for left or right foot, both in the forward foot posture (the foot standing in front at rest) and the starting foot used to initiate locomotion, a population-level right-foot preference was shown for the whole group and for each of the three age ranges considered (chick, young and adult). Ostriches are known to rely upon a lateralized behaviour during hatching (using their right foot to break the egg shell) suggesting the hypothesis that the precocious motor laterality observed at hatching might stand as a precursor of limb preference later in development, as already observed in other avian species. 2009 Elsevier B.V. All rights reserved.

Distant memories: a prospective study of vantage point of trauma memories.

PubMed

Kenny, Lucy M; Bryant, Richard A; Silove, Derrick; Creamer, Mark; O'Donnell, Meaghan; McFarlane, Alexander C

2009-09-01

Adopting an observer perspective to recall trauma memories may function as a form of avoidance that maintains posttraumatic stress disorder (PTSD). We conducted a prospective study to analyze the relationship between memory vantage point and PTSD symptoms. Participants (N= 947) identified the vantage point of their trauma memory and reported PTSD symptoms within 4 weeks of the trauma; 730 participants repeated this process 12 months later. Initially recalling the trauma from an observer vantage point was related to more severe PTSD symptoms at that time and 12 months later. Shifting from a field to an observer perspective a year after trauma was associated with greater PTSD severity at 12 months. These results suggest that remembering trauma from an observer vantage point is related to both immediate and ongoing PTSD symptoms.

Observations of ejecta clouds produced by impacts onto Saturn's rings.

PubMed

Tiscareno, Matthew S; Mitchell, Colin J; Murray, Carl D; Di Nino, Daiana; Hedman, Matthew M; Schmidt, Jürgen; Burns, Joseph A; Cuzzi, Jeffrey N; Porco, Carolyn C; Beurle, Kevin; Evans, Michael W

2013-04-26

We report observations of dusty clouds in Saturn's rings, which we interpret as resulting from impacts onto the rings that occurred between 1 and 50 hours before the clouds were observed. The largest of these clouds was observed twice; its brightness and cant angle evolved in a manner consistent with this hypothesis. Several arguments suggest that these clouds cannot be due to the primary impact of one solid meteoroid onto the rings, but rather are due to the impact of a compact stream of Saturn-orbiting material derived from previous breakup of a meteoroid. The responsible interplanetary meteoroids were initially between 1 centimeter and several meters in size, and their influx rate is consistent with the sparse prior knowledge of smaller meteoroids in the outer solar system.

LDEF electronic systems: Successes, failures, and lessons

NASA Technical Reports Server (NTRS)

Miller, Emmett; Porter, Dave; Smith, Dave; Brooks, Larry; Levorsen, Joe; Mulkey, Owen

1991-01-01

Following the Long Duration Exposure Facility (LDEF) retrieval, the Systems Special Investigation Group (SIG) participated in an extensive series of tests of various electronic systems, including the NASA provided data and initiate systems, and some experiment systems. Overall, these were found to have performed remarkably well, even though most were designed and tested under limited budgets and used at least some nonspace qualified components. However, several anomalies were observed, including a few which resulted in some loss of data. The postflight test program objectives, observations, and lessons learned from these examinations are discussed. All analyses are not yet complete, but observations to date will be summarized, including the Boeing experiment component studies and failure analysis results related to the Interstellar Gas Experiment. Based upon these observations, suggestions for avoiding similar problems on future programs are presented.

The origin of the structure of large-scale magnetic fields in disc galaxies

NASA Astrophysics Data System (ADS)

Nixon, C. J.; Hands, T. O.; King, A. R.; Pringle, J. E.

2018-07-01

The large-scale magnetic fields observed in spiral disc galaxies are often thought to result from dynamo action in the disc plane. However, the increasing importance of Faraday depolarization along any line of sight towards the galactic plane suggests that the strongest polarization signal may come from well above (˜0.3-1 kpc) this plane, from the vicinity of the warm interstellar medium (WIM)/halo interface. We propose (see also Henriksen & Irwin 2016) that the observed spiral fields (polarization patterns) result from the action of vertical shear on an initially poloidal field. We show that this simple model accounts for the main observed properties of large-scale fields. We speculate as to how current models of optical spiral structure may generate the observed arm/interarm spiral polarization patterns.

Technical Note: Determination of the SCS initial abstraction ratio in an experimental watershed in Greece

NASA Astrophysics Data System (ADS)

Baltas, E. A.; Dervos, N. A.; Mimikou, M. A.

2007-11-01

The present study was conducted in an experimental watershed in Attica, Greece, using observed rainfall/runoff events. The objective of the study was the determination of the initial abstraction ratio of the watershed. The average ratio (Ia/S) of the entire watershed was equal to 0.014. The corresponding ratio at a subwatershed was 0.037. The difference was attributed to the different spatial distribution of landuses and geological formations at the extent of the watershed. Both of the determined ratios are close to the ratio value of 0.05 that has been suggested from many studies for the improvement of the SCS-CN method.

Infrasonic induced ground motions

NASA Astrophysics Data System (ADS)

Lin, Ting-Li

On January 28, 2004, the CERI seismic network recorded seismic signals generated by an unknown source. Our conclusion is that the acoustic waves were initiated by an explosive source near the ground surface. The meteorological temperature and effective sound speed profiles suggested existence of an efficient near-surface waveguide that allowed the acoustic disturbance to propagate to large distances. An explosion occurring in an area of forest and farms would have limited the number of eyewitnesses. Resolution of the source might be possible by experiment or by detailed analysis of the ground motion data. A seismo-acoustic array was built to investigate thunder-induced ground motions. Two thunder events with similar N-wave waveforms but different horizontal slownesses are chosen to evaluate the credibility of using thunder as a seismic source. These impulsive acoustic waves excited P and S reverberations in the near surface that depend on both the incident wave horizontal slowness and the velocity structure in the upper 30 meters. Nineteen thunder events were chosen to further investigate the seismo-acoustic coupling. The consistent incident slowness differences between acoustic pressure and ground motions suggest that ground reverberations were first initiated somewhat away from the array. Acoustic and seismic signals were used to generate the time-domain transfer function through the deconvolution technique. Possible non-linear interaction for acoustic propagation into the soil at the surface was observed. The reverse radial initial motions suggest a low Poisson's ratio for the near-surface layer. The acoustic-to-seismic transfer functions show a consistent reverberation series of the Rayleigh wave type, which has a systematic dispersion relation to incident slownesses inferred from the seismic ground velocity. Air-coupled Rayleigh wave dispersion was used to quantitatively constrain the near-surface site structure with constraints afforded by near-surface body wave refraction and Rayleigh wave dispersion data. Theoretical standard high-frequency and air-coupled Rayleigh wave dispersion calculated by the inferred site structure match the observed dispersion curves. Our study suggests that natural or controlled air-borne pressure sources can be used to investigate the near-surface site structures for earthquake shaking hazard studies.

Effects of parents and Brown-headed Cowbirds (Molothrus ater) on nest predation risk for a songbird

PubMed Central

Latif, Quresh S; Heath, Sacha K; Rotenberry, John T

2012-01-01

Nest predation limits avian fitness, so ornithologists study nest predation, but they often only document patterns of predation rates without substantively investigating underlying mechanisms. Parental behavior and predator ecology are two fundamental drivers of predation rates and patterns, but the role of parents is less certain, particularly for songbirds. Previous work reproduced microhabitat-predation patterns experienced by Yellow Warblers (Setophaga petechia) in the Mono Lake basin at experimental nests without parents, suggesting that these patterns were driven by predator ecology rather than predator interactions with parents. In this study, we further explored effects of post-initiation parental behavior (nest defense and attendance) on predation risk by comparing natural versus experimental patterns related to territory density, seasonal timing of nest initiation, and nest age. Rates of parasitism by Brown-headed Cowbirds (Molothrus ater) were high in this system (49% nests parasitized), so we also examined parasitism-predation relationships. Natural nest predation rates (NPR) correlated negatively with breeding territory density and nonlinearly (U-shaped relationship) with nest-initiation timing, but experimental nests recorded no such patterns. After adjusting natural-nest data to control for these differences from experimental nests other than the presence of parents (e.g., defining nest failure similarly and excluding nestling-period data), we obtained similar results. Thus, parents were necessary to produce observed patterns. Lower natural NPR compared with experimental NPR suggested that parents reduced predation rates via nest defense, so this parental behavior or its consequences were likely correlated with density or seasonal timing. In contrast, daily predation rates decreased with nest age for both nest types, indicating this pattern did not involve parents. Parasitized nests suffered higher rates of partial predation but lower rates of complete predation, suggesting direct predation by cowbirds. Explicit behavioral research on parents, predators (including cowbirds), and their interactions would further illuminate mechanisms underlying the density, seasonal, and nest age patterns we observed. PMID:23301174

Control of Growth Rate by Initial Substrate Concentration at Values Below Maximum Rate

PubMed Central

Gaudy, Anthony F.; Obayashi, Alan; Gaudy, Elizabeth T.

1971-01-01

The hyperbolic relationship between specific growth rate, μ, and substrate concentration, proposed by Monod and used since as the basis for the theory of steady-state growth in continuous-flow systems, was tested experimentally in batch cultures. Use of a Flavobacterium sp. exhibiting a high saturation constant for growth in glucose minimal medium allowed direct measurement of growth rate and substrate concentration throughout the growth cycle in medium containing a rate-limiting initial concentration of glucose. Specific growth rates were also measured for a wide range of initial glucose concentrations. A plot of specific growth rate versus initial substrate concentration was found to fit the hyperbolic equation. However, the instantaneous relationship between specific growth rate and substrate concentration during growth, which is stated by the equation, was not observed. Well defined exponential growth phases were developed at initial substrate concentrations below that required for support of the maximum exponential growth rate and a constant doubling time was maintained until 50% of the substrate had been used. It is suggested that the external substrate concentration initially present “sets” the specific growth rate by establishing a steady-state internal concentration of substrate, possibly through control of the number of permeation sites. PMID:5137579

EIT And SXT Observations of a Quiet-Region Filament Ejection: First Eruption, Then Reconnection

NASA Technical Reports Server (NTRS)

Sterling, Alphonse C.; Moore, Ronald L.; Thompson, Barbara J.

2001-01-01

We observe a slow-onset quiet-region filament eruption with the Extreme Ultraviolet Imaging Telescope (EIT) on the Solar Heliospheric Observatory (SOHO) and the Soft X-ray Telescope (SXT) on Yohkoh. This event occurred on 1999 April 18 and was likely the origin of a coronal mass ejection detected by SOHO at 08:30 UT on that day. In the EIT observation, one-half of the filament shows two stages of evolution: stage 1 is a slow, roughly constant upward movement at approximately 1 km/s lasting approximately 0.5 hr, and stage 2 is a rapid upward eruption at approximately 16 km/s occurring just before the filament disappears into interplanetary space. The other half of the filament shows little motion along the line of sight during the time of stage 1 but erupts along with the rest of the filament during stage 2. There is no obvious emission from the filament in the SXT observation until stage 2; at that time, an arcade of EUV and soft X-ray loops forms first at the central location of the filament and then expands outward along the length of the filament channel. A plot of EUV intensity versus time of the central portion of the filament (where the postflare loops initially form) shows a flat profile during stage 1 and a rapid upturn after the start of stage 2. This light curve is delayed from what would be expected if 'tether-cutting' reconnection in the core of the erupting region were responsible for the initiation of the eruption. Rather, these observations suggest that a loss of stability of the magnetic field holding the filament initiates the eruption, with reconnection in the core region occurring only as a by-product.

Temporal framing and the hidden-zero effect: rate-dependent outcomes on delay discounting.

PubMed

Naudé, Gideon P; Kaplan, Brent A; Reed, Derek D; Henley, Amy J; DiGennaro Reed, Florence D

2018-05-01

Recent research suggests that presenting time intervals as units (e.g., days) or as specific dates, can modulate the degree to which humans discount delayed outcomes. Another framing effect involves explicitly stating that choosing a smaller-sooner reward is mutually exclusive to receiving a larger-later reward, thus presenting choices as an extended sequence. In Experiment 1, participants (N = 201) recruited from Amazon Mechanical Turk completed the Monetary Choice Questionnaire in a 2 (delay framing) by 2 (zero framing) design. Regression suggested a main effect of delay, but not zero, framing after accounting for other demographic variables and manipulations. We observed a rate-dependent effect for the date-framing group, such that those with initially steep discounting exhibited greater sensitivity to the manipulation than those with initially shallow discounting. Subsequent analyses suggest these effects cannot be explained by regression to the mean. Experiment 2 addressed the possibility that the null effect of zero framing was due to within-subject exposure to the hidden- and explicit-zero conditions. A new Amazon Mechanical Turk sample completed the Monetary Choice Questionnaire in either hidden- or explicit-zero formats. Analyses revealed a main effect of reward magnitude, but not zero framing, suggesting potential limitations to the generality of the hidden-zero effect. © 2018 Society for the Experimental Analysis of Behavior.

West Nile virus outbreak in Phoenix, Arizona--2010: entomological observations and epidemiological correlations.

PubMed

Colborn, James M; Smith, Kirk A; Townsend, John; Damian, Dan; Nasci, Roger S; Mutebi, John-Paul

2013-06-01

In 2010, Arizona experienced an unusually early and severe outbreak of West Nile virus (WNV) centered in the southeast section of Maricopa County. Entomological data were collected before and during the outbreak, from May 25 through July 31, 2010, using the CO2-baited light trap monitoring system maintained by Maricopa County Vector Control. In the outbreak area, the most abundant species in the Town of Gilbert and in the area covered by the Roosevelt Water Conservation District was Culex quinquefasciatus, constituting 75.1% and 71.8% of the total number of mosquitoes collected, respectively. Vector index (VI) profiles showed that the abundance of infected Cx. quinquefasciatus peaked prior to human cases, suggesting that this species was involved in the initiation of the outbreak. In contrast, the VI profiles for Cx. tarsalis were consistently low, suggesting limited involvement in initiating and sustaining transmission. Taken together, the higher abundance and the VI profiles strongly suggest that Cx. quinquefasciatus was the primary vector for this outbreak. The VI profiles consistently showed that the abundance of infected mosquitoes peaked 1 to 2 wk before the peaks of human cases, suggesting that VI could have successfully been utilized to predict the WNV outbreak in Maricopa County, AZ, in 2010.

Successful management of metastatic transmissible venereal tumour to skin of mammary region.

PubMed

Varughese, E E; Singla, V K; Ratnakaran, U; Gandotra, V K

2012-12-01

A Dalmatian female presented with a history of vaginal bleeding and was diagnosed as having transmissible venereal tumour (TVT) after cytological examination of the vaginal growth revealed typical TVT cells. A cytology of the aspirate from multiple nodules in the skin near the abdominal and inguinal pair of mammary glands revealed similar cells suggestive of metastasis to skin of mammary region. Chemotherapy was initiated with weekly injections of vincristine sulphate (0.025 mg/kg BW, IV, SID) and haematological examination was performed pre- and post-treatment to assess the prognosis of the patient and side effects of the drug. The major side effects observed during the course of the treatment were high body temperature, mild neutropaenia and significant decrease in packed cell volume, haemoglobin, total leucocyte and erythrocyte count. Four weekly injections of vincristine were administered, and 4 weeks from initiation of treatment, the tumour and nodules were gone, suggesting complete recovery. © 2012 Blackwell Verlag GmbH.

Can A Food Retailer-Based Healthier Foods Initiative Improve The Nutrient Profile Of US Packaged Food Purchases? A Case Study Of Walmart, 2000-2013

PubMed Central

Smith, Lindsey; Ng, Shu Wen; Popkin, Barry M.

2015-01-01

Healthier foods initiatives (HFIs) by national food retailers offer an opportunity to improve the nutritional profile of packaged food purchases (PFPS). Using a longitudinal dataset of US household PFPs, with methods to account for selectivity of shopping at a specific retailer, we modeled the effect of Walmart’s HFI using counterfactual simulations to examine observed vs. expected changes in the nutritional profile of Walmart PFPs. From 2000 to 2013, Walmart PFPs showed major declines in energy, sodium, and sugar density, as well as declines in sugary beverages, grain-based desserts, snacks, and candy, beyond trends at similar retailers. However, post-HFI declines were similar to what we expected based on pre-HFI trends, suggesting that these changes were not attributable to Walmart’s HFI. These results suggest that food retailer-based HFIs may not be sufficient to improve the nutritional profile of food purchases. PMID:26526244

Diagenetic palaeotemperatures from aqueous fluid inclusions: re- equilibration of inclusions in carbonate cements by burial heating.

USGS Publications Warehouse

Burruss, R.C.

1987-01-01

Calculations based on the observed behaviour of inclusions in fluorite under external confining P allows prediction of the T and depths of burial necessary to initiate re-equilibration of aqueous inclusions in the common size range 40-4 mu m. Heating of 20-60oC over the initial trapping T may cause errors of 10-20oC in the homogenization T. This suggests that re-equilibration may cause aqueous inclusions in carbonates to yield a poor record of their low-T history, but a useful record of the maximum T experienced by the host rock. Previous work suggests that inclusions containing petroleum fluids will be less susceptible to re-equilibration.This and the following six abstracts represent papers presented at a joint meeting of the Applied Mineralogy Group of the Mineralogical Society and the Petroleum Group of the Geological Society held in Newcastle upon Tyne in April 1986.-R.A.H.

The investigation of short-term variations of Jupiter's Synchrotron Radiation with the large radio interferometer GMRT

NASA Astrophysics Data System (ADS)

Imai, Kota; Misawa, Hiroaki; Bhardwaj, Anil; Tsuchiya, Fuminori; Doi, Akihiro; Kondo, Tetsuro; Morioka, Akira

The goal of this research is to investigate physical processes of short term variations of Jupiter's Synchrotron Radiation (JSR) which is important for revealing the origin of relativistic electrons at Jupiter's Radiation Belt (JRB). JSR has been frequently observed by radio interferometers and single dish radio telescopes to understand characteristics of the spatial distribution and variations inferring dynamics and energetics of the relativistic electrons. Observations with radio interferometers have showed JSR source structure (Dunn et al., 2003, etc), and contributed to modeling of JRB (Garrett et al., 2005, etc). On the other hand, observations of total intensity of JSR with a single dish radio telescope have revealed characteristics of time variable phenomena. The time variations are indispensable parameters giving clues to understand particle source and/or loss processes which characterize the formation of JRB. Recently, Miyoshi et al. (1999) and Bolton et al. (2002) confirmed the existence of short term (days to weeks) variations in JSR. The detection of short term variations makes a great impact on the study on JRB because it has been believed for a long time that the strong internal magnetic field and rapidly rotating magnetosphere of Jupiter protect the JRB region from solar wind variations and magnetospheric disturbances as theoretically suggested by de Pater and Goertz (1994). So far we have made the JSR observations to investigate the short term variations of mainly several hundreds MHz JSR which is emitted by low energy particles (< 10MeV) and has been observed systematically only few times (Miyoshi et al., 1999, Misawa et al., 2005, etc). The latter observation suggested that the short term variation is a general feature at low frequencies. Therefore, it is essential to study its detailed characteristics and the causalities. Theoretically expected physical processes which are responsible for the short term variation are enhanced radial diffusion initiated by solar UV flux enhancement and scattering of the JRB particles toward the polar region by whistler-mode wave, although it is still not known whether solar UV flux or whistler-mode wave is a dominant initiator. In order to investigate physical processes of short term variations, we observed JSR with the Giant Metrewave Radio Telescope (GMRT) from 23rd May 2007 to 27th June 2007. Bhardwaj et al. (2005) first made JSR observations with the GMRT for about a week in 2003 and suggested that JSR flux increased with Solar 10.7cm radio flux (F10.7), which is correlated to solar UV flux. On the other hand, the initial results of GMRT observation in 2007 show that the total flux of JSR varies in several days but is not strongly correlated to F10.7. Then, when the total flux of JSR increased, the peak position of JSR moved outward, and the flux of JSR increased in the outer emitting region. It is implied that the other acceleration processes cause these variations except the enhanced radial diffusion, because enhanced radial diffusion increases the flux of JSR and the peak position of JSR moves toward Jupiter. In this presentation, we will discuss the variations of JSR spatial distribution shown in the 2007 GMRT observation results. Acknowledgement: We would like to appreciate helpful support of Ishwara Chandra C. H. And, we thank the staff of the GMRT who have made these observations possible. GMRT is run by the National Centre for Radio Astrophysics of the Tata Institute of Fundamental Research.

National strategy for suicide prevention in Japan: impact of a national fund on progress of developing systems for suicide prevention and implementing initiatives among local authorities.

PubMed

Nakanishi, Miharu; Yamauchi, Takashi; Takeshima, Tadashi

2015-01-01

In Japan, the Cabinet Office released the 'General Principles of Suicide Prevention Policy' in 2007 and suggested nine initiatives. In 2009, a national fund was launched to help prefectures (the administrative divisions of Japan) and local authorities implement five categories of suicide-prevention programs. This paper examines the impact of the national fund on the establishment of the systems for suicide prevention and the implementation of these initiatives among local authorities. The present study included 1385 local authorities (79.5%) from all 47 prefectures that responded to the cross-sectional questionnaire survey. Improved suicide-prevention systems and the implementation of nine initiatives in April 2013 were observed among 265 local authorities (19.1%) that implemented 'Training of community service providers' and 'Public awareness campaigns'; 178 local authorities (12.9%) that implemented 'Face-to-face counseling', 'Training of community service providers' and 'Public awareness campaigns'; and 324 local authorities (23.4%) that implemented 'Trauma-informed policies and practices'. There was no significant difference in suicide-prevention systems and the implementation of nine initiatives between 203 local authorities (14.7%) that implemented only 'Public awareness campaigns' and 231 local authorities (16.7%) that did not implement any suicide-prevention programs. The results of our study suggest that the national fund promoted the establishment of community systems for suicide prevention and helped implement initiatives among local authorities. The national suicide-prevention strategy in Japan should explore a standard package of programs to guide community suicide-prevention efforts with a sustained workforce among local authorities. © 2014 The Authors. Psychiatry and Clinical Neurosciences © 2014 Japanese Society of Psychiatry and Neurology.

Collisional quenching at ultralow energies: controlling efficiency with internal state selection.

PubMed

Bovino, S; Bodo, E; Gianturco, F A

2007-12-14

Calculations have been carried out for the vibrational quenching of excited H(2) molecules which collide with Li(+) ions at ultralow energies. The dynamics has been treated exactly using the well-known quantum coupled-channel expansions over different initial vibrational levels. The overall interaction potential has been obtained from the calculations carried out earlier by our group using highly correlated ab initio methods. The results indicate that specific features of the scattering observables, e.g., the appearance of Ramsauer-Townsend minima in elastic channel cross sections and the marked increase of the cooling rates from specific initial states, can be linked to potential properties at vanishing energies (sign and size of scattering lengths) and to the presence of either virtual states or bound states. The suggestion is made such that by selecting the initial state preparation of the molecular partners, the ionic interactions would be amenable to controlling quenching efficiency at ultralow energies.

Shock experiments on maskelynite-bearing anorthosite

NASA Technical Reports Server (NTRS)

Lambert, P.; Grieve, R. A. F.

1984-01-01

A series of shock recovery experiments over 9.9-60.4 GPa have been carried out on naturally shocked anorthosite from the Mistastin impact structure in Labrador consisting primarily of diaplectic plagioclase glass or maskelynite, An(50), and pyroxene. Petrographic observations of the experimental products indicate that the component minerals and diaplectic glasses generally retained their initial character throughout, the only exception being the increase in fracturing which occurred in the 9.9 GPa shot. Reshocking at pressures higher than the initial shock tends to lower the refractive index of maskelynite. The increase in refractive index of maskelynite reshocked to pressures lower than the initial pressure is interpreted as due to shock densification of the diaplectic glass above the Hugoniot elastic limit and below the mixed phase regime. The data suggest that the low-high-low density transition of maskelynite occurs about 8 GPa below that of the crystal of corresponding composition.

Effects of pressure rise on cw laser ablation of tissue

NASA Astrophysics Data System (ADS)

LeCarpentier, Gerald L.; Motamedi, Massoud; Welch, Ashley J.

1991-06-01

The objectives of this research were to identify mechanisms responsible for the initiation of continuous wave (cw) laser ablation of tissue and investigate the role of pressure in the ablation process. Porcine aorta samples were irradiated in a chamber pressurized from 1 X 10-4 to 12 atmospheres absolute pressure. Acrylic and Zn-Se windows in the experimental pressure chamber allowed video and infrared cameras to simultaneously record mechanical and thermal events associated with cw argon laser ablation of these samples. Video and thermal images of tissue slabs documented the explosive nature of cw laser ablation of soft biological media and revealed similar ablation threshold temperatures and ablation onset times under different environmental pressures; however, more violent initiation explosions with decreasing environmental pressures were observed. These results suggest that ablation initiates with thermal alterations in the mechanical strength of the tissue and proceeds with an explosion induced by the presence superheated liquid within the tissue.

A mathematical basis for plant patterning derived from physico-chemical phenomena.

PubMed

Beleyur, Thejasvi; Abdul Kareem, Valiya Kadavu; Shaji, Anil; Prasad, Kalika

2013-04-01

The position of leaves and flowers along the stem axis generates a specific pattern, known as phyllotaxis. A growing body of evidence emerging from recent computational modeling and experimental studies suggests that regulators controlling phyllotaxis are chemical, e.g. the plant growth hormone auxin and its dynamic accumulation pattern by polar auxin transport, and physical, e.g. mechanical properties of the cell. Here we present comprehensive views on how chemical and physical properties of cells regulate the pattern of leaf initiation. We further compare different computational modeling studies to understand their scope in reproducing the observed patterns. Despite a plethora of experimental studies on phyllotaxis, understanding of molecular mechanisms of pattern initiation in plants remains fragmentary. Live imaging of growth dynamics and physicochemical properties at the shoot apex of mutants displaying stable changes from one pattern to another should provide mechanistic insights into organ initiation patterns. Copyright © 2013 WILEY Periodicals, Inc.

Silicon Carbide Radioisotope Batteries

NASA Technical Reports Server (NTRS)

Rybicki, George C.

2005-01-01

The substantial radiation resistance and large bandgap of SiC semiconductor materials makes them an attractive candidate for application in a high efficiency, long life radioisotope battery. To evaluate their potential in this application, simulated batteries were constructed using SiC diodes and the alpha particle emitter Americium Am-241 or the beta particle emitter Promethium Pm-147. The Am-241 based battery showed high initial power output and an initial conversion efficiency of approximately 16%, but the power output decayed 52% in 500 hours due to radiation damage. In contrast the Pm-147 based battery showed a similar power output level and an initial conversion efficiency of approximately 0.6%, but no degradation was observed in 500 hours. However, the Pm-147 battery required approximately 1000 times the particle fluence as the Am-242 battery to achieve a similar power output. The advantages and disadvantages of each type of battery and suggestions for future improvements will be discussed.

Shock initiation of 2,4-dinitroimidazole (2,4-DNI)

NASA Astrophysics Data System (ADS)

Urtiew, P. A.; Tarver, C. M.; Simpson, R. L.

1996-05-01

The shock sensitivity of the pressed solid explosive 2,4-dinitroimidazole (2,4-DNI) was determined using the embedded manganin pressure gauge technique. At an initial shock pressure of 2 GPa, several microseconds were required before any exothermic reaction was observed. At 4 GPa, 2,4-DNI reacted more rapidly but did not transition to detonation at the 12 mm deep gauge position. At 6 GPa, detonation occurred in less than 6 mm of shock propagation. Thus, 2,4-DNI is more shock sensitive than TATB-based explosives but is considerably less shock sensitive than HMX-based explosives. An Ignition and Growth reactive flow model for 2,4-DNI based on these gauge records showed that 2,4-DNI exhibits shock initiation characteristics similar to TATB but reacts faster. The chemical structure of 2,4-DNI suggests that it may exhibit thermal decomposition reactions similar to nitroguanine and explosives with similar ring structures, such as ANTA and NTO.

Use and cost comparison of clobazam to other antiepileptic drugs for treatment of Lennox-Gastaut syndrome

PubMed Central

François, Clément; Stern, John M.; Ogbonnaya, Augustina; Lokhandwala, Tasneem; Landsman-Blumberg, Pamela; Duhig, Amy; Shen, Vivienne; Tan, Robin

2017-01-01

ABSTRACT Background: Lennox-Gastaut syndrome (LGS) is a severe form of childhood-onset epilepsy associated with serious injuries due to frequent and severe seizures. Of the antiepileptic drugs (AEDs) approved for LGS, clobazam is a more recent market entrant, having been approved in October 2011. Recent AED budget impact and cost-effectiveness analyses for LGS suggest that adding clobazam to a health plan formulary may result in decreased medical costs; however, research on clinical and economic outcomes and treatment patterns with these AED treatments in LGS is limited. Objectives: To compare the baseline characteristics and treatment patterns of new initiators of clobazam and other AEDs among LGS patients and compare healthcare utilization and costs before and after clobazam initiation among LGS patients. Methods: A retrospective study of probable LGS patients was conducted using the MarketScan® Commercial, Medicare Supplemental, and Medicaid databases (10/1/2010-3/31/2014). Results: In the Commercial/Medicare Supplemental population, clobazam users were younger, had fewer comorbidities, and more prior AED use than non-clobazam users. In the 12 months pre-treatment initiation, clobazam users had significantly more seizure-related inpatient stays and outpatient visits and higher total seizure-related (P < 0.001) and all-cause (P < 0.001) costs than non-clobazam users. Among clobazam users, when compared to the 12 months pre-clobazam initiation, seizure-related medical utilization and costs were lower in the 12 months post-clobazam initiation (P = 0.004). Total all-cause (P < 0.001) and seizure-related (P = 0.029) costs increased post-clobazam initiation mainly due to the increase in outpatient pharmacy costs. Similar results were observed in the Medicaid population. Conclusions: Baseline results suggest a prescribing preference for clobazam in severe LGS patients. Clobazam users had a reduction in seizure-related medical utilization and costs after clobazam initiation. The improvement in medical costs mostly offset the higher prescription costs following clobazam initiation. PMID:28740620

Earth Observing System, Conclusions and Recommendations

NASA Technical Reports Server (NTRS)

1984-01-01

The following Earth Observing Systems (E.O.S.) recommendations were suggested: (1) a program must be initiated to ensure that present time series of Earth science data are maintained and continued. (2) A data system that provides easy, integrated, and complete access to past, present, and future data must be developed as soon as possible. (3) A long term research effort must be sustained to study and understand these time series of Earth observations. (4) The E.O.S. should be established as an information system to carry out those aspects of the above recommendations which go beyond existing and currently planned activities. (5) The scientific direction of the E.O.S. should be established and continued through an international scientific steering committee.

Sexual Risk Behavior in Young Adulthood: Broadening the Scope Beyond Early Sexual Initiation

PubMed Central

Epstein, Marina; Bailey, Jennifer A.; Manhart, Lisa E.; Hill, Karl G.; Hawkins, J. David

2013-01-01

A robust link between early sexual initiation and sexual risk-taking behavior is reported in previous studies. The relationship may not be causal, however, as the effect of common risk factors is often not considered. The current study examined whether early initiation is a key predictor of risky sexual behavior in the 20s and 30s, over and above co-occurring individual and environmental factors. Data were drawn from the Seattle Social Development Project, a longitudinal panel of 808 youth. Early predictors (ages 10–15) and sexual risk-taking (ages 21–24 and 30–33) were assessed prospectively. Early sexual initiation (before age 15) was entered into a series of probit regressions that also included family, neighborhood, peer, and individual risk factors. Although a positive bivariate relation between early sexual initiation and sexual risk-taking was observed at both ages, the link did not persist when co-occurring risk factors were included. Behavioral disinhibition and antisocial peer influences emerged as the strongest predictors of sexual risk over and above early sexual initiation. These results suggest that early sexual initiation must be considered in the context of common antecedents; public health policy aimed at delaying sexual intercourse alone is unlikely to substantially reduce sexual risk behavior in young adulthood. PMID:24423058

'Peeling a comet': Layering of comet analogues

NASA Astrophysics Data System (ADS)

Kaufmann, E.; Hagermann, A.

2017-09-01

Using a simple comet analogue we investigate the influence of subsurface solar light absorption by dust. We found that a sample initially consisting of loose water ice grains and carbon particles becomes significantly harder after being irradiated with artificial sunlight for several hours. Further a drastic change of the sample surface could be observed. These results suggests that models should treat the nucleus surface as an interactive transitional zone to better represent cometary processes.

All-aromatic biphenylene end-capped polyquinoline and polyimide matrix resins

NASA Technical Reports Server (NTRS)

Droske, J. P.; Stille, J. K.; Alston, W. B.

1985-01-01

Biphenylene end-capped polyquinoline and polyimide resins afford low void content graphite-reinforced composites with good initial properties. However, with both resins, rapid degradation occurs during oxidative isothermal aging at elevated temperatures. The degradation is not observed during isothermal aging under a nitrogen atmosphere which suggests that the biphenylene end-cap (or the resulting crosslink/chain extension structures) is not particularly thermooxidatively stable. The nature of the thermooxidative instability is currently under investigation.

The mineralogy of ordinary chondrites and implications for asteroid spectrophotometry

NASA Technical Reports Server (NTRS)

Mcsween, Harry Y., Jr.; Bennett, Marvin E., III; Jarosewich, Eugene

1991-01-01

Published data from bulk chemical analyses of 94 ordinary chondrites are compiled in a table of normative mineralogy and discussed in detail. Significant variations in olivine, pyroxene, and metal abundance ratios are found within each chondrite class and attributed to redox processes superimposed on initial differences in metal/silicate ratios. The use of the diagrams constructed here to predict the mineralogic characteristics of asteroids on the basis of spectrophotometric observations is suggested.

The positive regulatory function of the 5'-proximal open reading frames in GCN4 mRNA can be mimicked by heterologous, short coding sequences.

PubMed Central

Williams, N P; Mueller, P P; Hinnebusch, A G

1988-01-01

Translational control of GCN4 expression in the yeast Saccharomyces cerevisiae is mediated by multiple AUG codons present in the leader of GCN4 mRNA, each of which initiates a short open reading frame of only two or three codons. Upstream AUG codons 3 and 4 are required to repress GCN4 expression in normal growth conditions; AUG codons 1 and 2 are needed to overcome this repression in amino acid starvation conditions. We show that the regulatory function of AUG codons 1 and 2 can be qualitatively mimicked by the AUG codons of two heterologous upstream open reading frames (URFs) containing the initiation regions of the yeast genes PGK and TRP1. These AUG codons inhibit GCN4 expression when present singly in the mRNA leader; however, they stimulate GCN4 expression in derepressing conditions when inserted upstream from AUG codons 3 and 4. This finding supports the idea that AUG codons 1 and 2 function in the control mechanism as translation initiation sites and further suggests that suppression of the inhibitory effects of AUG codons 3 and 4 is a general consequence of the translation of URF 1 and 2 sequences upstream. Several observations suggest that AUG codons 3 and 4 are efficient initiation sites; however, these sequences do not act as positive regulatory elements when placed upstream from URF 1. This result suggests that efficient translation is only one of the important properties of the 5' proximal URFs in GCN4 mRNA. We propose that a second property is the ability to permit reinitiation following termination of translation and that URF 1 is optimized for this regulatory function. Images PMID:3065626

Amplification of the 20q Chromosomal Arm Occurs Early in Tumorigenic Transformation and May Initiate Cancer

PubMed Central

Buganim, Yosef; Solomon, Hilla; Goldfinger, Naomi; Hovland, Randi; Ke, Xi-Song; Oyan, Anne M.; Kalland, Karl-H.; Rotter, Varda; Domany, Eytan

2011-01-01

Duplication of chromosomal arm 20q occurs in prostate, cervical, colon, gastric, bladder, melanoma, pancreas and breast cancer, suggesting that 20q amplification may play a causal role in tumorigenesis. According to an alternative view, chromosomal imbalance is mainly a common side effect of cancer progression. To test whether a specific genomic aberration might serve as a cancer initiating event, we established an in vitro system that models the evolutionary process of early stages of prostate tumor formation; normal prostate cells were immortalized by the over-expression of human telomerase catalytic subunit hTERT, and cultured for 650 days till several transformation hallmarks were observed. Gene expression patterns were measured and chromosomal aberrations were monitored by spectral karyotype analysis at different times. Several chromosomal aberrations, in particular duplication of chromosomal arm 20q, occurred early in the process and were fixed in the cell populations, while other aberrations became extinct shortly after their appearance. A wide range of bioinformatic tools, applied to our data and to data from several cancer databases, revealed that spontaneous 20q amplification can promote cancer initiation. Our computational model suggests that 20q amplification induced deregulation of several specific cancer-related pathways including the MAPK pathway, the p53 pathway and Polycomb group factors. In addition, activation of Myc, AML, B-Catenin and the ETS family transcription factors was identified as an important step in cancer development driven by 20q amplification. Finally we identified 13 "cancer initiating genes", located on 20q13, which were significantly over-expressed in many tumors, with expression levels correlated with tumor grade and outcome suggesting that these genes induce the malignant process upon 20q amplification. PMID:21297939

Anelasticity of olivine single crystals investigated by stress-reduction tests and high-angular resolution electron backscatter diffraction

NASA Astrophysics Data System (ADS)

Wallis, D.; Hansen, L. N.; Kempton, I.; Wilkinson, A. J.

2017-12-01

Geodynamic phenomena, including glacial isostatic adjustment and postseismic deformation, can involve transient deformation in response to changes in differential stress acting on mantle rocks. As such, rheological models of transient deformation are incorporated in predictions of associated processes, including sea-level rise and stress redistribution after earthquakes. However, experimental constraints on rheological models for transient deformation of mantle materials are sparse. In particular, experiments involving stress reductions have been lacking. Moreover, a material's response to a reduction in stress can provide clues to the microphysical processes controlling deformation. To constrain models of transient deformation of mantle rocks we performed stress-reduction tests on single crystals of olivine at 1250-1300°C. Mechanical and piezoelectric actuators controlled constant initial stress during creep. At various strain intervals stress was reduced near-instantaneously using the piezoelectric actuator, inducing both elastic and anelastic (time-dependent) lengthening of the samples. A range of magnitudes of stress reduction were applied, typically unloading 10-90% of the initial stress. High-angular resolution electron backscatter diffraction (HR-EBSD), based on cross-correlation of diffraction patterns, was used to map dislocation density and elastic strain distributions in the recovered samples. Magnitudes of anelastic back-strain increase with increasing magnitudes of stress reduction and show a marked increase when stress reductions exceed 50% of the initial stress, consistent with previous observations in metals and alloys. This observation is inconsistent with the Burgers rheological model commonly used to describe transient behaviour and suggests that the style of rheological behaviour depends on the magnitude of stress change. HR-EBSD maps reveal that the crystal lattices are smoothly curved and generally lack subgrain boundaries and elastic strain heterogeneities. The dependence of the anelastic behaviour on the initial stress, combined with the lack of subgrain boundaries, suggest that the anelastic behaviour is controlled by local interactions between dislocations, rather than resistance imposed by the lattice or subgrain boundaries.

Review of proton pump inhibitors for the initial treatment of heartburn: is there a dose ceiling effect?

PubMed

Kushner, Pamela R; Peura, David A

2011-05-01

Proton pump inhibitors (PPIs) are widely used in clinical practice. However, concerns have been expressed about their long-term use, particularly with regard to bone health, Clostridium difficile infections, and drug interactions with platelet aggregation inhibitors. There has been limited guidance for clinicians concerning appropriate dose selection of PPIs for the initial treatment of heartburn. This review explored whether published clinical trials provide evidence of a ceiling above which higher PPI doses do not provide additional clinical benefit over the lowest approved dose. All articles of randomized, controlled clinical trials in nonerosive gastroesophageal reflux disease (GERD) in which the effects of two or more doses of the same PPI on symptomatic relief of heartburn were quantified as a study endpoint were identified and analyzed through PubMed searches up to the end of September 2010. The majority of trials evaluated provided no evidence that higher PPI doses were superior to the lowest approved dose for the initial treatment of heartburn. There were no clinically relevant findings with respect to dose dependence and safety outcomes in these studies. Efficacy outcomes from the trials suggest there may be a dose ceiling effect and highlight the need for further research on the use of the lowest effective PPI doses as an appropriate strategy in the initial treatment of uncomplicated heartburn. Observational studies and some meta-analyses have suggested that long-term PPI pharmacotherapy might be associated with safety concerns, which necessitate the periodic evaluation of therapeutic benefit in terms of symptom resolution and regimen tolerability. However, evidence to date suggests that use of the lowest effective dose for the indication is not associated with significant adverse events, particularly in the short term. Clinical practice suggests that patients requiring long-term treatment should be maintained on the lowest dose necessary to control symptoms, and monitored for potentially confounding factors that may lead to safety concerns.

Evidence for Gravity Wave Seeding of Convective Ionospheric Storms Possibly Initiated by Thunderstorms

NASA Astrophysics Data System (ADS)

Kelley, M. C.; Dao, E. V.

2018-05-01

With the increase in solar activity, the Communication/Outage Forecast System satellite decayed on orbit to below the F peak. As such, we can study the development of convective ionospheric storms and, most importantly, study large-scale seeding of the responsible instability. For decades, gravity has been suggested as being responsible for the long wavelengths in the range of 200 to 1,000 km, as are commonly observed using airglow and satellite data. Here we suggest that convective thunderstorms are a likely source of gravity waves and point out that recent theoretical analysis has shown this connection to be quite possible.

Topological defect clustering and plastic deformation mechanisms in functionalized graphene

NASA Astrophysics Data System (ADS)

Nunes, Ricardo; Araujo, Joice; Chacham, Helio

2011-03-01

We present ab initio results suggesting that strain plays a central role in the clustering of topological defects in strained and functionalized graphene models. We apply strain onto the topological-defect graphene networks from our previous work, and obtain topological-defect clustering patterns which are in excellent agreement with recent observations in samples of reduced graphene oxide. In our models, the graphene layer, containing an initial concentration of isolated topological defects, is covered by hydrogen or hydroxyl groups. Our results also suggest a rich variety of plastic deformation mechanism in functionalized graphene systems. We acknowledge support from the Brazilian agencies: CNPq, Fapemig, and INCT-Materiais de Carbono.

On the role of ice-nucleating aerosol in the formation of ice particles in tropical mesoscale convective systems

NASA Astrophysics Data System (ADS)

Ladino, Luis A.; Korolev, Alexei; Heckman, Ivan; Wolde, Mengistu; Fridlind, Ann M.; Ackerman, Andrew S.

2017-02-01

Over the decades, the cloud physics community has debated the nature and role of aerosol particles in ice initiation. The present study shows that the measured concentration of ice crystals in tropical mesoscale convective systems exceeds the concentration of ice nucleating particles (INPs) by several orders of magnitude. The concentration of INPs was assessed from the measured aerosol particle concentration in the size range of 0.5 to 1 µm. The observations from this study suggest that primary ice crystals formed on INPs make only a minor contribution to the total concentration of ice crystals in tropical mesoscale convective systems. This is found by comparing the predicted INP number concentrations with in situ ice particle number concentrations. The obtained measurements suggest that ice multiplication is the likely explanation for the observed high concentrations of ice crystals in this type of convective system.

On the role of ice-nucleating aerosol in the formation of ice particles in tropical mesoscale convective systems

PubMed Central

Ladino, Luis A.; Korolev, Alexei; Heckman, Ivan; Wolde, Mengistu; Fridlind, Ann M.; Ackerman, Andrew S.

2018-01-01

Over decades, the cloud physics community has debated the nature and role of aerosol particles in ice initiation. The present study shows that the measured concentration of ice crystals in tropical mesoscale convective systems exceeds the concentration of ice nucleating particles (INPs) by several orders of magnitude. The concentration of INPs was assessed from the measured aerosol particles concentration in the size range of 0.5 to 1 µm. The observations from this study suggest that primary ice crystals formed on INPs make only a minor contribution to the total concentration of ice crystals in tropical mesoscale convective systems. This is found by comparing the predicted INP number concentrations with in-situ ice particle number concentrations. The obtained measurements suggest that ice multiplication is the likely explanation for the observed high concentrations of ice crystals in this type of convective system. PMID:29551842

Time course of VMN lesion effects on lordosis and proceptive behavior in female hamsters.

PubMed

Floody, Owen R

2002-06-01

Previous studies suggest that ultrasound production by female hamsters is better able than other reproductive behaviors to recover from an initial drop caused by damage to the ventromedial hypothalamus (VMN). At the same time, few studies have examined the time course of such lesion effects. To remedy this, female hamsters were observed before and after control operations or VMN lesions. The behaviors considered were ultrasound production, lordosis, approach, and vaginal marking. Ultrasound production, lordosis, and approach were affected by lesions, permitting the description of the time course of each of these effects. Only ultrasound rates showed evidence of recovery, which culminated in rates significantly above those observed preoperatively in the same animals. This suggests that ultrasound production is unusual in its response to VMN damage and that the underlying mechanism could be of interest in studies of the processes that determine recovery from brain damage. (c) 2002 Elsevier Science (USA).

Does unconscious thought improve complex decision making?

PubMed

Rey, Arnaud; Goldstein, Ryan M; Perruchet, Pierre

2009-05-01

In a recent study, Dijksterhuis et al. (Science 311:1005, 2006) reported that participants were better at solving complex decisions after a period of unconscious thought relative to a period of conscious thought. They interpreted their results as an existence proof of powerful unconscious deliberation mechanisms. In the present report, we used a similar experimental design with an additional control, immediate condition, and we observed that participants produced as good (and even descriptively better) decisions in this condition than in the "unconscious" one, hence challenging the initial interpretation of the authors. However, we still obtained lower performances in the "conscious" relative to the "immediate" condition, suggesting that the initial result of Dijksterhuis et al. was not due to the action of powerful unconscious thought processes, but to the apparent disadvantage of further conscious processing. We provide an explanation for this observation on the basis of current models of decision making. It is finally concluded that the benefit of unconscious thought in complex decision making is still a controversial issue that should be considered cautiously.

Sex-typing behavior and sex-typing pressure in child/parent interaction.

PubMed

Jacklin, C N; DiPietro, J A; Maccoby, E E

1984-10-01

The sex-typing of children and the sex-typing pressure of parents was investigated during free play in a home visit. There were 30 male and 24 female 45-month-olds observed with their mothers and fathers in separate free-play sessions during which an array of both sex-stereotyped and neutral toys were available. Behavioral observations were recorded for a variety of parent, child, and dyadic behaviors, including initiations of sex-typed play, total sex-typed play, and rough-and-tumble play. Children initiated sex-typed play and played with sex-appropriate toys. Father-child and mother-daughter dyads were more likely to engage in thematic play appropriate to the child's sex, while in mother-son dyads equal amounts of masculine and feminine play occurred. In addition father-son dyads displayed the highest levels of rough-and tumble play and arousal of child by parent. The results suggest that fathers are the discriminating influence on sex-appropriate play.

Anomalous behavior in temporal evolution of ripple wavelength under medium energy Ar{sup +}-ion bombardment on Si: A case of initial wavelength selection

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

Garg, Sandeep Kumar; Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110 067; Cuerno, Rodolfo

We have studied the early stage dynamics of ripple patterns on Si surfaces, in the fluence range of 1–3 × 10{sup 18} ions cm{sup −2}, as induced by medium energy Ar{sup +}-ion irradiation at room temperature. Under our experimental conditions, the ripple evolution is found to be in the linear regime, while a clear decreasing trend in the ripple wavelength is observed up to a certain time (fluence). Numerical simulations of a continuum model of ion-sputtered surfaces suggest that this anomalous behavior is due to the relaxation of the surface features of the experimental pristine surface during the initial stage of patternmore » formation. The observation of this hitherto unobserved behavior of the ripple wavelength seems to have been enabled by the use of medium energy ions, where the ripple wavelengths are found to be order(s) of magnitude larger than those at lower ion energies.« less

Modeling of the Bosphorus exchange flow dynamics

NASA Astrophysics Data System (ADS)

Sözer, Adil; Özsoy, Emin

2017-04-01

The fundamental hydrodynamic behavior of the Bosphorus Strait is investigated through a numerical modeling study using alternative configurations of idealized or realistic geometry. Strait geometry and basin stratification conditions allow for hydraulic controls and are ideally suited to support the maximal-exchange regime, which determines the rate of exchange of waters originating from the adjacent Black and Mediterranean Seas for a given net transport. Steady-state hydraulic controls are demonstrated by densimetric Froude number calculations under layered flow approximations when corrections are applied to account for high velocity shears typically observed in the Bosphorus. Analyses of the model results reveal many observed features of the strait, including critical transitions at hydraulic controls and dissipation by turbulence and hydraulic jumps. It is found that the solution depends on initialization, especially with respect to the basin initial conditions. Significant differences between the controlled maximal-exchange and drowned solutions suggest that a detailed modeling implementation involving coupling with adjacent basins needs to take full account of the Bosphorus Strait in terms of the physical processes to be resolved.

In situ nano- to microscopic imaging and growth mechanism of electrochemical dissolution (e.g., corrosion) of a confined metal surface

PubMed Central

Merola, C.; Cheng, H.-W.; Schwenzfeier, K.; Kristiansen, K.; Chen, Y.-J.; Dobbs, H. A.; Valtiner, M.

2017-01-01

Reactivity in confinement is central to a wide range of applications and systems, yet it is notoriously difficult to probe reactions in confined spaces in real time. Using a modified electrochemical surface forces apparatus (EC-SFA) on confined metallic surfaces, we observe in situ nano- to microscale dissolution and pit formation (qualitatively similar to previous observation on nonmetallic surfaces, e.g., silica) in well-defined geometries in environments relevant to corrosion processes. We follow “crevice corrosion” processes in real time in different pH-neutral NaCl solutions and applied surface potentials of nickel (vs. Ag|AgCl electrode in solution) for the mica–nickel confined interface of total area ∼0.03 mm2. The initial corrosion proceeds as self-catalyzed pitting, visualized by the sudden appearance of circular pits with uniform diameters of 6–7 μm and depth ∼2–3 nm. At concentrations above 10 mM NaCl, pitting is initiated at the outer rim of the confined zone, while below 10 mM NaCl, pitting is initiated inside the confined zone. We compare statistical analysis of growth kinetics and shape evolution of individual nanoscale deep pits with estimates from macroscopic experiments to study initial pit growth and propagation. Our data and experimental techniques reveal a mechanism that suggests initial corrosion results in formation of an aggressive interfacial electrolyte that rapidly accelerates pitting, similar to crack initiation and propagation within the confined area. These results support a general mechanism for nanoscale material degradation and dissolution (e.g., crevice corrosion) of polycrystalline nonnoble metals, alloys, and inorganic materials within confined interfaces. PMID:28827338

Modeling Archean Subduction Initiation from Continental Spreading with a Free-Surface

NASA Astrophysics Data System (ADS)

Adams, A.; Thielmann, M.; Golabek, G.

2017-12-01

Earth is the only planet known to have plate tectonics, however the onset of plate tectonics and Earth's early tectonic environment are highly uncertain. Modern plate tectonics are characterized by the sinking of dense lithosphere at subduction zones; however this process may not have been feasible if Earth's interior was hotter in the Archean, resulting in thicker and more buoyant oceanic lithosphere than observed at present [van Hunen and van den Berg, 2008]. Previous studies have proposed gravitational spreading of early continents at passive margins as a mechanism to trigger early episodes of plate subduction using numerical simulations with a free-slip upper boundary condition [Rey et al., 2014]. This study utilizes 2D thermo-mechanical numerical experiments using the finite element code MVEP2 [Kaus, 2010; Thielmann et al., 2014] to investigate the viability of this mechanism for subduction initiation in an Archean mantle for both free-slip and free-surface models. Radiogenic heating, strain weakening, and eclogitization were systematically implemented to determine critical factors for modeling subduction initiation. In free-slip models, results show episodes of continent spreading and subduction initiation of oceanic lithosphere for low limiting yield stresses (100-150 MPa) and increasing continent width with no dependency on radiogenic heating, strain weakening, or eclogitization. For models with a free-surface, subduction initiation was observed at low limiting yield stresses (100-225 MPa) with increasing continent width and only in models with eclogitization. Initial lithospheric stress states were studied as a function of density and viscosity ratios between continent and oceanic lithosphere, and results indicate the magnitude of lithospheric stresses increases with increasing continental buoyancy. This work suggests continent spreading may trigger episodes of subduction in models with a free-surface with critical factors being low limiting yield stresses and eclogitization.

Vitamin A Deprivation Affects the Progression of the Spermatogenic Wave and Initial Formation of the Blood-testis Barrier, Resulting in Irreversible Testicular Degeneration in Mice

PubMed Central

CHIHARA, Masataka; OTSUKA, Saori; ICHII, Osamu; KON, Yasuhiro

2013-01-01

Abstract The blood testis-barrier (BTB) is essential for maintaining homeostasis in the seminiferous epithelium. Although many studies have reported that vitamin A (VA) is required for the maintenance of spermatogenesis, the relationships between the BTB, spermatogenesis and VA have not been elucidated. In this study, we analyzed BTB assembly and spermatogenesis in the testes of mice fed the VA-deficient (VAD) diet from the prepubertal period to adulthood. During the prepubertal period, no changes were observed in the initiation and progression of the first spermatogenic wave in mice fed the VAD diet. However, the numbers of preleptotene/leptotene spermatocytes derived from the second spermatogenic wave onwards were decreased, and initial BTB formation was also delayed, as evidenced by the decreased expression of mRNAs encoding BTB components and VA signaling molecules. From 60 days postpartum, mice fed the VAD diet exhibited apoptosis of germ cells, arrest of meiosis, disruption of the BTB, and dramatically decreased testis size. Furthermore, vacuolization and calcification were observed in the seminiferous epithelium of adult mice fed the VAD diet. Re-initiation of spermatogenesis by VA replenishment in adult mice fed the VAD diet rescued BTB assembly after when the second spermatogenic wave initiated from the arrested spermatogonia reached the preleptotene/leptotene spermatocytes. These results suggested that BTB integrity was regulated by VA metabolism with meiotic progression and that the impermeable BTB was required for persistent spermatogenesis rather than meiotic initiation. In conclusion, consumption of the VAD diet led to critical defects in spermatogenesis progression and altered the dynamics of BTB assembly. PMID:23934320

Replication Validity of Initial Association Studies: A Comparison between Psychiatry, Neurology and Four Somatic Diseases.

PubMed

Dumas-Mallet, Estelle; Button, Katherine; Boraud, Thomas; Munafo, Marcus; Gonon, François

2016-01-01

There are growing concerns about effect size inflation and replication validity of association studies, but few observational investigations have explored the extent of these problems. Using meta-analyses to measure the reliability of initial studies and explore whether this varies across biomedical domains and study types (cognitive/behavioral, brain imaging, genetic and "others"). We analyzed 663 meta-analyses describing associations between markers or risk factors and 12 pathologies within three biomedical domains (psychiatry, neurology and four somatic diseases). We collected the effect size, sample size, publication year and Impact Factor of initial studies, largest studies (i.e., with the largest sample size) and the corresponding meta-analyses. Initial studies were considered as replicated if they were in nominal agreement with meta-analyses and if their effect size inflation was below 100%. Nominal agreement between initial studies and meta-analyses regarding the presence of a significant effect was not better than chance in psychiatry, whereas it was somewhat better in neurology and somatic diseases. Whereas effect sizes reported by largest studies and meta-analyses were similar, most of those reported by initial studies were inflated. Among the 256 initial studies reporting a significant effect (p<0.05) and paired with significant meta-analyses, 97 effect sizes were inflated by more than 100%. Nominal agreement and effect size inflation varied with the biomedical domain and study type. Indeed, the replication rate of initial studies reporting a significant effect ranged from 6.3% for genetic studies in psychiatry to 86.4% for cognitive/behavioral studies. Comparison between eight subgroups shows that replication rate decreases with sample size and "true" effect size. We observed no evidence of association between replication rate and publication year or Impact Factor. The differences in reliability between biological psychiatry, neurology and somatic diseases suggest that there is room for improvement, at least in some subdomains.

Replication Validity of Initial Association Studies: A Comparison between Psychiatry, Neurology and Four Somatic Diseases

PubMed Central

Dumas-Mallet, Estelle; Button, Katherine; Boraud, Thomas; Munafo, Marcus; Gonon, François

2016-01-01

Context There are growing concerns about effect size inflation and replication validity of association studies, but few observational investigations have explored the extent of these problems. Objective Using meta-analyses to measure the reliability of initial studies and explore whether this varies across biomedical domains and study types (cognitive/behavioral, brain imaging, genetic and “others”). Methods We analyzed 663 meta-analyses describing associations between markers or risk factors and 12 pathologies within three biomedical domains (psychiatry, neurology and four somatic diseases). We collected the effect size, sample size, publication year and Impact Factor of initial studies, largest studies (i.e., with the largest sample size) and the corresponding meta-analyses. Initial studies were considered as replicated if they were in nominal agreement with meta-analyses and if their effect size inflation was below 100%. Results Nominal agreement between initial studies and meta-analyses regarding the presence of a significant effect was not better than chance in psychiatry, whereas it was somewhat better in neurology and somatic diseases. Whereas effect sizes reported by largest studies and meta-analyses were similar, most of those reported by initial studies were inflated. Among the 256 initial studies reporting a significant effect (p<0.05) and paired with significant meta-analyses, 97 effect sizes were inflated by more than 100%. Nominal agreement and effect size inflation varied with the biomedical domain and study type. Indeed, the replication rate of initial studies reporting a significant effect ranged from 6.3% for genetic studies in psychiatry to 86.4% for cognitive/behavioral studies. Comparison between eight subgroups shows that replication rate decreases with sample size and “true” effect size. We observed no evidence of association between replication rate and publication year or Impact Factor. Conclusion The differences in reliability between biological psychiatry, neurology and somatic diseases suggest that there is room for improvement, at least in some subdomains. PMID:27336301

Role of defects in laser-induced modifications of silica coatings and fused silica using picosecond pulses at 1053 nm: II Scaling laws and the density of precursors

DOE PAGES

Laurence, T. A.; Negres, R. A.; Ly, S.; ...

2017-06-22

Here, we investigate the role of defects in laser-induced damage of fused silica and of silica coatings produced by e-beam and PIAD processes which are used in damage resistant, multi-layer dielectric, reflective optics. We perform experiments using 1053 nm, 1–60 ps laser pulses with varying beam size, number of shots, and pulse widths in order to understand the characteristics of defects leading to laser-induced damage. This pulse width range spans a transition in mechanisms from intrinsic material ablation for short pulses to defect-dominated damage for longer pulses. We show that for pulse widths as short as 10 ps, laser-induced damagemore » properties of fused silica and silica films are dominated by isolated absorbers. The density of these precursors and their fluence dependence of damage initiation suggest a single photon process for initial energy absorption in these precursors. Higher density precursors that initiate close to the ablation threshold at shorter pulse widths are also observed in fused silica, whose fluence and pulse width scaling suggest a multiphoton initiation process. We also show that these initiated damage sites grow with subsequent laser pulses. We show that scaling laws obtained in more conventional ways depend on the beam size and on the definition of damage for ps pulses. For this reason, coupling scaling laws with the density of precursors are critical to understanding the damage limitations of optics in the ps regime.« less

Activation of human herpesvirus replication by apoptosis.

PubMed

Prasad, Alka; Remick, Jill; Zeichner, Steven L

2013-10-01

A central feature of herpesvirus biology is the ability of herpesviruses to remain latent within host cells. Classically, exposure to inducing agents, like activating cytokines or phorbol esters that stimulate host cell signal transduction events, and epigenetic agents (e.g., butyrate) was thought to end latency. We recently showed that Kaposi's sarcoma-associated herpesvirus (KSHV, or human herpesvirus-8 [HHV-8]) has another, alternative emergency escape replication pathway that is triggered when KSHV's host cell undergoes apoptosis, characterized by the lack of a requirement for the replication and transcription activator (RTA) protein, accelerated late gene kinetics, and production of virus with decreased infectivity. Caspase-3 is necessary and sufficient to initiate the alternative replication program. HSV-1 was also recently shown to initiate replication in response to host cell apoptosis. These observations suggested that an alternative apoptosis-triggered replication program might be a general feature of herpesvirus biology and that apoptosis-initiated herpesvirus replication may have clinical implications, particularly for herpesviruses that almost universally infect humans. To explore whether an alternative apoptosis-initiated replication program is a common feature of herpesvirus biology, we studied cell lines latently infected with Epstein-Barr virus/HHV-4, HHV-6A, HHV-6B, HHV-7, and KSHV. We found that apoptosis triggers replication for each HHV studied, with caspase-3 being necessary and sufficient for HHV replication. An alternative apoptosis-initiated replication program appears to be a common feature of HHV biology. We also found that commonly used cytotoxic chemotherapeutic agents activate HHV replication, which suggests that treatments that promote apoptosis may lead to activation of latent herpesviruses, with potential clinical significance.

Activation of Human Herpesvirus Replication by Apoptosis

PubMed Central

Prasad, Alka; Remick, Jill

2013-01-01

A central feature of herpesvirus biology is the ability of herpesviruses to remain latent within host cells. Classically, exposure to inducing agents, like activating cytokines or phorbol esters that stimulate host cell signal transduction events, and epigenetic agents (e.g., butyrate) was thought to end latency. We recently showed that Kaposi's sarcoma-associated herpesvirus (KSHV, or human herpesvirus-8 [HHV-8]) has another, alternative emergency escape replication pathway that is triggered when KSHV's host cell undergoes apoptosis, characterized by the lack of a requirement for the replication and transcription activator (RTA) protein, accelerated late gene kinetics, and production of virus with decreased infectivity. Caspase-3 is necessary and sufficient to initiate the alternative replication program. HSV-1 was also recently shown to initiate replication in response to host cell apoptosis. These observations suggested that an alternative apoptosis-triggered replication program might be a general feature of herpesvirus biology and that apoptosis-initiated herpesvirus replication may have clinical implications, particularly for herpesviruses that almost universally infect humans. To explore whether an alternative apoptosis-initiated replication program is a common feature of herpesvirus biology, we studied cell lines latently infected with Epstein-Barr virus/HHV-4, HHV-6A, HHV-6B, HHV-7, and KSHV. We found that apoptosis triggers replication for each HHV studied, with caspase-3 being necessary and sufficient for HHV replication. An alternative apoptosis-initiated replication program appears to be a common feature of HHV biology. We also found that commonly used cytotoxic chemotherapeutic agents activate HHV replication, which suggests that treatments that promote apoptosis may lead to activation of latent herpesviruses, with potential clinical significance. PMID:23885073

Role of defects in laser-induced modifications of silica coatings and fused silica using picosecond pulses at 1053 nm: II Scaling laws and the density of precursors

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

Laurence, T. A.; Negres, R. A.; Ly, S.

Here, we investigate the role of defects in laser-induced damage of fused silica and of silica coatings produced by e-beam and PIAD processes which are used in damage resistant, multi-layer dielectric, reflective optics. We perform experiments using 1053 nm, 1–60 ps laser pulses with varying beam size, number of shots, and pulse widths in order to understand the characteristics of defects leading to laser-induced damage. This pulse width range spans a transition in mechanisms from intrinsic material ablation for short pulses to defect-dominated damage for longer pulses. We show that for pulse widths as short as 10 ps, laser-induced damagemore » properties of fused silica and silica films are dominated by isolated absorbers. The density of these precursors and their fluence dependence of damage initiation suggest a single photon process for initial energy absorption in these precursors. Higher density precursors that initiate close to the ablation threshold at shorter pulse widths are also observed in fused silica, whose fluence and pulse width scaling suggest a multiphoton initiation process. We also show that these initiated damage sites grow with subsequent laser pulses. We show that scaling laws obtained in more conventional ways depend on the beam size and on the definition of damage for ps pulses. For this reason, coupling scaling laws with the density of precursors are critical to understanding the damage limitations of optics in the ps regime.« less

A method of initial orbit determination from three or more observations on a short arc. (Russian Title: Метод определения первоначальной орбиты по трем и более наблюдениям на короткой дуге)

NASA Astrophysics Data System (ADS)

Shefer, V. A.

2010-12-01

A new method is suggested for computing the initial orbit of a small celestial body from its three or more pairs of angular measurements at three times. The method is based on using the approach that we previously developed for constructing the intermediate orbit from minimal number of observations. This intermediate orbit allows for most of the perturbations in the motion of the body under study. The method proposed uses the Herget's algorithmic scheme that makes it possible to involve additional observations as well. The methodical error of orbit computation by the proposed method is two orders smaller than the corresponding error of the Herget's approach based on the construction of the unperturbed Keplerian orbit. The new method is especially efficient if applied to high-accuracy observational data covering short orbital arcs.

Understanding the Host Galaxies of Tidal Disruption Flares

NASA Astrophysics Data System (ADS)

Stone, Nicholas; Generozov, Aleksey; Vasiliev, Eugene; Metzger, Brian

2018-01-01

Recent observations suggest that stellar tidal disruption events (TDE) are strongly overrepresented in rare, post-starburst galaxies. Several dynamical mechanisms have been proposed to elevate their TDE rates, ranging from central stellar overdensities to the presence of supermassive black hole (SMBH) binaries. These, and other, dynamical hypotheses can be disentangled by comparing observations to theoretical predictions for the TDE delay time distribution (DTD). We show that SMBH binaries are a less plausible solution for the post-starburst preference, as they can only reproduce the observed DTD with extensive fine-tuning. The overdensity hypothesis produces a reasonable match to the observed DTD (based on the limited data currently available), provided that the initial stellar density profile created during the starburst, ρ(r), is exceptional in both steepness and normalization. In particular, explaining the post-starburst preference requires ρ∝r‑γ with γ>2.5, i.e. much steeper than the classic Bahcall-Wolf equilibrium profile of γ=7/4. Radial velocity anisotropies also represent a promising explanation, provided that initial anisotropy parameters of β0≈0.5 are sustainable against the radial orbit instability. As the sample of TDEs with well-studied host galaxies grows, the DTD will become a powerful tool for constraining the exceptional dynamical properties of post-starburst galactic nuclei.

Hidden secrets of deformation: Impact-induced compaction within a CV chondrite

NASA Astrophysics Data System (ADS)

Forman, L. V.; Bland, P. A.; Timms, N. E.; Collins, G. S.; Davison, T. M.; Ciesla, F. J.; Benedix, G. K.; Daly, L.; Trimby, P. W.; Yang, L.; Ringer, S. P.

2016-10-01

The CV3 Allende is one of the most extensively studied meteorites in worldwide collections. It is currently classified as S1-essentially unshocked-using the classification scheme of Stöffler et al. (1991), however recent modelling suggests the low porosity observed in Allende indicates the body should have undergone compaction-related deformation. In this study, we detail previously undetected evidence of impact through use of Electron Backscatter Diffraction mapping to identify deformation microstructures in chondrules, AOAs and matrix grains. Our results demonstrate that forsterite-rich chondrules commonly preserve crystal-plastic microstructures (particularly at their margins); that low-angle boundaries in deformed matrix grains of olivine have a preferred orientation; and that disparities in deformation occur between chondrules, surrounding and non-adjacent matrix grains. We find heterogeneous compaction effects present throughout the matrix, consistent with a highly porous initial material. Given the spatial distribution of these crystal-plastic deformation microstructures, we suggest that this is evidence that Allende has undergone impact-induced compaction from an initially heterogeneous and porous parent body. We suggest that current shock classifications (Stöffler et al., 1991) relying upon data from chondrule interiors do not constrain the complete shock history of a sample.

Synchrony and motor mimicking in chimpanzee observational learning

PubMed Central

Fuhrmann, Delia; Ravignani, Andrea; Marshall-Pescini, Sarah; Whiten, Andrew

2014-01-01

Cumulative tool-based culture underwrote our species' evolutionary success, and tool-based nut-cracking is one of the strongest candidates for cultural transmission in our closest relatives, chimpanzees. However the social learning processes that may explain both the similarities and differences between the species remain unclear. A previous study of nut-cracking by initially naïve chimpanzees suggested that a learning chimpanzee holding no hammer nevertheless replicated hammering actions it witnessed. This observation has potentially important implications for the nature of the social learning processes and underlying motor coding involved. In the present study, model and observer actions were quantified frame-by-frame and analysed with stringent statistical methods, demonstrating synchrony between the observer's and model's movements, cross-correlation of these movements above chance level and a unidirectional transmission process from model to observer. These results provide the first quantitative evidence for motor mimicking underlain by motor coding in apes, with implications for mirror neuron function. PMID:24923651

Synchrony and motor mimicking in chimpanzee observational learning.

PubMed

Fuhrmann, Delia; Ravignani, Andrea; Marshall-Pescini, Sarah; Whiten, Andrew

2014-06-13

Cumulative tool-based culture underwrote our species' evolutionary success, and tool-based nut-cracking is one of the strongest candidates for cultural transmission in our closest relatives, chimpanzees. However the social learning processes that may explain both the similarities and differences between the species remain unclear. A previous study of nut-cracking by initially naïve chimpanzees suggested that a learning chimpanzee holding no hammer nevertheless replicated hammering actions it witnessed. This observation has potentially important implications for the nature of the social learning processes and underlying motor coding involved. In the present study, model and observer actions were quantified frame-by-frame and analysed with stringent statistical methods, demonstrating synchrony between the observer's and model's movements, cross-correlation of these movements above chance level and a unidirectional transmission process from model to observer. These results provide the first quantitative evidence for motor mimicking underlain by motor coding in apes, with implications for mirror neuron function.

Oxidation of silicon with a 5 eV O(-) beam

NASA Technical Reports Server (NTRS)

Hecht, M. H.; Orient, O. J.; Chutjian, A.; Vasquez, R. P.

1989-01-01

A silicon wafer has been oxidized at room temperature in vacuum using a pure, ground-state beam of O(-) ions. The beam was of sufficiently low energy that no displacement damage or implantation was energetically possible. The resulting SiO2 films were analyzed with X-ray photoelectron spectroscopy. A logarithmic dependence of oxide thickness on dose was observed, with an extrapolated oxidation efficiency of unity for the clean silicon surface. A distinct initial oxidation phase was observed, with an anomalously high level of silicon suboxides. In addition, the valence-band offset between the silicon and the oxide was unusually small, suggesting a large interfacial dipole.

Quark correlations in the color glass condensate: Pauli blocking and the ridge

NASA Astrophysics Data System (ADS)

Altinoluk, Tolga; Armesto, Néstor; Beuf, Guillaume; Kovner, Alex; Lublinsky, Michael

2017-02-01

We consider, for the first time, correlations between quarks produced in p-A collisions in the framework of the color glass condensate. We find a quark-quark ridge that shows a dip at Δ η ˜2 relative to the gluon-gluon ridge. The origin of this dip is the short-range (in rapidity) Pauli blocking experienced by quarks in the wave function of the incoming projectile. We observe that these correlations, present in the initial state, survive the scattering process. We suggest that this effect may be observable in open charm-open charm correlations at the Large Hadron Collider.

The 2014-2015 warming anomaly in the Southern California Current System observed by underwater gliders

NASA Astrophysics Data System (ADS)

Zaba, Katherine D.; Rudnick, Daniel L.

2016-02-01

Large-scale patterns of positive temperature anomalies persisted throughout the surface waters of the North Pacific Ocean during 2014-2015. In the Southern California Current System, measurements by our sustained network of underwater gliders reveal the coastal effects of the recent warming. Regional upper ocean temperature anomalies were greatest since the initiation of the glider network in 2006. Additional observed physical anomalies included a depressed thermocline, high stratification, and freshening; induced biological consequences included changes in the vertical distribution of chlorophyll fluorescence. Contemporaneous surface heat flux and wind strength perturbations suggest that local anomalous atmospheric forcing caused the unusual oceanic conditions.

Coordination and Integration of Global Ocean Observing through JCOMM

NASA Astrophysics Data System (ADS)

Legler, D. M.; Meldrum, D. T.; Hill, K. L.; Charpentier, E.

2016-02-01

The primary objective of the JCOMM Observations Coordination Group (OCG) is to provide technical coordination to implement fully integrated ocean observing system across the entire marine meteorology and oceanographic community. JCOMM OCG works in partnership with the Global Ocean Observing System, , which focusses on setting observing system requirements and conducting evalutions. JCOMM OCG initially focused on major global observing networks (e.g. Argo profiling floats, moored buoys, ship based observations, sea level stations, reference sites, etc), and is now expanding its horizon in recognition of new observing needs and new technologies/networks (e.g. ocean gliders). Over the next five years the JCOMM OCG is focusing its attention on integration and coordination in four major areas: observing network implementation particularly in response to integrated ocean observing requirements; observing system monitoring and metrics; standards and best practices; and improving integrated data management and access. This presentation will describe the scope and mission of JCOMM OCG; summarize the state of the global ocean observing system; highlight recent successes and resources for the research, prediction, and assessment communities; summarize our plans for the next several years; and suggest engagement opportunities.

Thickness distribution of a cooling pyroclastic flow deposit on Augustine Volcano, Alaska: Optimization using InSAR, FEMs, and an adaptive mesh algorithm

USGS Publications Warehouse

Masterlark, Timothy; Lu, Zhong; Rykhus, Russell P.

2006-01-01

Interferometric synthetic aperture radar (InSAR) imagery documents the consistent subsidence, during the interval 1992–1999, of a pyroclastic flow deposit (PFD) emplaced during the 1986 eruption of Augustine Volcano, Alaska. We construct finite element models (FEMs) that simulate thermoelastic contraction of the PFD to account for the observed subsidence. Three-dimensional problem domains of the FEMs include a thermoelastic PFD embedded in an elastic substrate. The thickness of the PFD is initially determined from the difference between post- and pre-eruption digital elevation models (DEMs). The initial excess temperature of the PFD at the time of deposition, 640 °C, is estimated from FEM predictions and an InSAR image via standard least-squares inverse methods. Although the FEM predicts the major features of the observed transient deformation, systematic prediction errors (RMSE = 2.2 cm) are most likely associated with errors in the a priori PFD thickness distribution estimated from the DEM differences. We combine an InSAR image, FEMs, and an adaptive mesh algorithm to iteratively optimize the geometry of the PFD with respect to a minimized misfit between the predicted thermoelastic deformation and observed deformation. Prediction errors from an FEM, which includes an optimized PFD geometry and the initial excess PFD temperature estimated from the least-squares analysis, are sub-millimeter (RMSE = 0.3 mm). The average thickness (9.3 m), maximum thickness (126 m), and volume (2.1 × 107m3) of the PFD, estimated using the adaptive mesh algorithm, are about twice as large as the respective estimations for the a priori PFD geometry. Sensitivity analyses suggest unrealistic PFD thickness distributions are required for initial excess PFD temperatures outside of the range 500–800 °C.

The initial cooling of pahoehoe flow lobes

USGS Publications Warehouse

Keszthelyi, L.; Denlinger, R.

1996-01-01

In this paper we describe a new thermal model for the initial cooling of pahoehoe lava flows. The accurate modeling of this initial cooling is important for understanding the formation of the distinctive surface textures on pahoehoe lava flows as well as being the first step in modeling such key pahoehoe emplacement processes as lava flow inflation and lava tube formation. This model is constructed from the physical phenomena observed to control the initial cooling of pahoehoe flows and is not an empirical fit to field data. We find that the only significant processes are (a) heat loss by thermal radiation, (b) heat loss by atmospheric convection, (c) heat transport within the flow by conduction with temperature and porosity-dependent thermal properties, and (d) the release of latent heat during crystallization. The numerical model is better able to reproduce field measurements made in Hawai'i between 1989 and 1993 than other published thermal models. By adjusting one parameter at a time, the effect of each of the input parameters on the cooling rate was determined. We show that: (a) the surfaces of porous flows cool more quickly than the surfaces of dense flows, (b) the surface cooling is very sensitive to the efficiency of atmospheric convective cooling, and (c) changes in the glass forming tendency of the lava may have observable petrographic and thermal signatures. These model results provide a quantitative explanation for the recently observed relationship between the surface cooling rate of pahoehoe lobes and the porosity of those lobes (Jones 1992, 1993). The predicted sensitivity of cooling to atmospheric convection suggests a simple field experiment for verification, and the model provides a tool to begin studies of the dynamic crystallization of real lavas. Future versions of the model can also be made applicable to extraterrestrial, submarine, silicic, and pyroclastic flows.

Topical Review: Integrating Findings on Direct Observation of Family Communication in Studies Comparing Pediatric Chronic Illness and Typically Developing Samples.

PubMed

Murphy, Lexa K; Murray, Caitlin B; Compas, Bruce E

2017-01-01

To review research on observed family communication in families with children with chronic illnesses compared with families with healthy, typically developing children, and to integrate findings utilizing a unifying family communication framework. Topical review of studies that have directly observed family communication in pediatric populations and included a typically developing comparison group. Initial findings from 14 studies with diverse approaches to quantifying observed family communication suggest that families with children with chronic illnesses may demonstrate lower levels of warm and structured communication and higher levels of hostile/intrusive and withdrawn communication compared with families with healthy, typically developing children. An integrative framework of family communication may be used in future studies that examine the occurrence, correlates, and mechanisms of family communication in pediatric populations.

Impulsivity-hyperactivity and subtypes of aggression in early childhood: an observational and short-term longitudinal study.

PubMed

Ostrov, Jamie M; Godleski, Stephanie A

2009-08-01

This short-term longitudinal study (N = 112) was conducted to explore the concurrent and prospective associations between teacher-reported impulsive-hyperactive behavior and observed relational and physical aggression during early childhood (M = 45.54 months old, SD = 9.07). Multiple informants and methods including observational methods (i.e., 160 min per child) were used to assess aggression and impulsivity-hyperactivity. All measures were found to be valid and reliable. Prospective hierarchical regression analyses revealed that impulsivity-hyperactivity was associated with increases in observed physical aggression across time, controlling for initial relational aggression and gender. These findings add to the growing developmental psychopathology literature that suggests that distinguishing between subtypes of aggression during early childhood may be important for understanding the course of impulsivity-hyperactivity in young children. Implications for practice are discussed.

A longitudinal study of exposure to retail cigarette advertising and smoking initiation.

PubMed

Henriksen, Lisa; Schleicher, Nina C; Feighery, Ellen C; Fortmann, Stephen P

2010-08-01

Accumulating evidence suggests that widespread advertising for cigarettes at the point of sale encourages adolescents to smoke; however, no longitudinal study of exposure to retail tobacco advertising and smoking behavior has been reported. A school-based survey included 1681 adolescents (aged 11-14 years) who had never smoked. One measure of exposure assessed the frequency of visiting types of stores that contain the most cigarette advertising. A more detailed measure combined data about visiting stores near school with observations of cigarette advertisements and pack displays in those stores. Follow-up surveys 12 and 30 months after baseline (retention rate: 81%) documented the transition from never to ever smoking, even just a puff. After 12 months, 18% of adolescents initiated smoking, but the incidence was 29% among students who visited convenience, liquor, or small grocery stores at least twice per week and 9% among those who reported the lowest visit frequency (less than twice per month). Adjusting for multiple risk factors, the odds of initiation remained significantly higher (odds ratio: 1.64 [95% confidence interval: 1.06-2.55]) for adolescents who reported moderate visit frequency (0.5-1.9 visits per week), and the odds of initiation more than doubled for those who visited > or = 2 times per week (odds ratio: 2.58 [95% confidence interval: 1.68-3.97]). Similar associations were observed for the more detailed exposure measure and persisted at 30 months. Exposure to retail cigarette advertising is a risk factor for smoking initiation. Policies and parenting practices that limit adolescents' exposure to retail cigarette advertising could improve smoking prevention efforts.

UK prescribing practices as proxy markers of unmet need in allergic rhinitis: a retrospective observational study

PubMed Central

Price, David B; Scadding, Glenis; Bachert, Claus; Saleh, Hesham; Nasser, Shuaib; Carter, Victoria; von Ziegenweidt, Julie; Durieux, Alice M S; Ryan, Dermot

2016-01-01

Little data on UK prescribing patterns and treatment effectiveness for allergic rhinitis (AR) are available. We quantified unmet pharmacologic needs in AR by assessing AR treatment effectiveness based on the prescribing behaviour of UK general practitioners (GP) during two consecutive pollen seasons (2009 and 2010). We conducted a retrospective observational study with the data from the Optimum Patient Care Research Database. We assessed diagnoses and prescription data for patients with a recorded diagnosis of rhinitis who took rhinitis medication during the study period. We assessed the data from 25,069 patients in 2009 and 22,381 patients in 2010. Monotherapy was the initial prescription of the season for 67% of patients with seasonal AR (SAR) and 77% of patients with nonseasonal upper airways disease (NSUAD), for both years. Initial oral antihistamine (OAH) or intranasal corticosteroid (INS) monotherapy proved insufficient for >20% of SAR and >37% of NSUAD patients. Multiple therapy was the initial prescription for 33% of SAR and 23% of NSUAD in both years, rising to 45% and >50% by season end, respectively. For NSUAD, dual-therapy prescriptions doubled and triple-therapy prescriptions almost tripled during both seasons. Many patients revisited their GP regardless of initial prescription. Initial OAH or INS monotherapy provides insufficient symptom control for many AR patients. GPs often prescribe multiple therapies at the start of the season, with co-prescription becoming more common as the season progresses. However, patients prescribed multiple therapies frequently revisit their GP, presumably to adjust treatment. These data suggest the need for more effective AR treatment and management strategies. PMID:27334893

Impulsive ankle push-off powers leg swing in human walking.

PubMed

Lipfert, Susanne W; Günther, Michael; Renjewski, Daniel; Seyfarth, Andre

2014-04-15

Rapid unloading and a peak in power output of the ankle joint have been widely observed during push-off in human walking. Model-based studies hypothesize that this push-off causes redirection of the body center of mass just before touch-down of the leading leg. Other research suggests that work done by the ankle extensors provides kinetic energy for the initiation of swing. Also, muscle work is suggested to power a catapult-like action in late stance of human walking. However, there is a lack of knowledge about the biomechanical process leading to this widely observed high power output of the ankle extensors. In our study, we use kinematic and dynamic data of human walking collected at speeds between 0.5 and 2.5 m s(-1) for a comprehensive analysis of push-off mechanics. We identify two distinct phases, which divide the push-off: first, starting with positive ankle power output, an alleviation phase, where the trailing leg is alleviated from supporting the body mass, and second, a launching phase, where stored energy in the ankle joint is released. Our results show a release of just a small part of the energy stored in the ankle joint during the alleviation phase. A larger impulse for the trailing leg than for the remaining body is observed during the launching phase. Here, the buckling knee joint inhibits transfer of power from the ankle to the remaining body. It appears that swing initiation profits from an impulsive ankle push-off resulting from a catapult without escapement.

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

Kim, Yoo-Shin; Lee, Tae Hoon; O'Neill, Brian E., E-mail: BEOneill@houstonmethodist.org

Non-lethal hyperthermia is used clinically as adjuvant treatment to radiation, with mixed results. Denaturation of protein during hyperthermia treatment is expected to synergize with radiation damage to cause cell cycle arrest and apoptosis. Alternatively, hyperthermia is known to cause tissue level changes in blood flow, increasing the oxygenation and radiosensitivity of often hypoxic tumors. In this study, we elucidate a third possibility, that hyperthermia alters cellular adhesion and mechanotransduction, with particular impact on the cancer stem cell population. We demonstrate that cell heating results in a robust but temporary loss of cancer cell aggressiveness and metastatic potential in mouse models.more » In vitro, this heating results in a temporary loss in cell mobility, adhesion, and proliferation. Our hypothesis is that the loss of cellular adhesion results in suppression of cancer stem cells and loss of tumor virulence and metastatic potential. Our study suggests that the metastatic potential of cancer is particularly reduced by the effects of heat on cellular adhesion and mechanotransduction. If true, this could help explain both the successes and failures of clinical hyperthermia, and suggest ways to target treatments to those who would most benefit. - Highlights: • Non-lethal hyperthermia treatment of cancer cells is shown to cause a reduction in rates of tumor initiation and metastasis. • Dynamic imaging of cells during heat treatment shows temporary changes in cell shape, cell migration, and cell proliferation. • Loss of adhesion may lead to the observed effect, which may disproportionately impact the tumor initiating cell fraction. • Loss or suppression of the tumor initiating cell fraction results in the observed loss of metastatic potential in vivo. • This result may lead to new approaches to synergizing hyperthermia with surgery, radiation, and chemotherapy.« less

First High-resolution Spectroscopic Observations by IRIS of a Fast, Helical Prominence Eruption Associated with a Coronal Mass Ejection

NASA Astrophysics Data System (ADS)

Liu, W.; De Pontieu, B.; Okamoto, T. J.; Vial, J. C.; Title, A. M.; Antolin, P.; Berger, T. E.; Uitenbroek, H.

2014-12-01

High-resolution spectroscopic observations of prominence eruptions and associated coronal mass ejections (CMEs) are rare but can provide valuable plasma and energy diagnostics. New opportunities have recently become available with the advent of the Interface Region Imaging Spectrograph (IRIS) mission equipped with high resolution of 0.33-0.4 arcsec in space and 1 km/s in velocity, together with the Hinode Solar Optical Telescope of 0.2 arcsec spatial resolution. We report the first result of joint IRIS-Hinode observations of a spectacular prominence eruption occurring on 2014-May-09. IRIS detected a maximum redshift of 450 km/s, which, combined with the plane-of-sky speed of 800 km/s, gives a large velocity vector of 920 km/s at 30 degrees from the sky plane. This direction agrees with the source location at 30 degrees behind the limb observed by STEREO-A and indicates a nearly vertical ejection. We found two branches of redshifts separated by 200 km/s appearing in all strong lines at chromospheric to transition-region temperatures, including Mg II k/h, C II, and Si IV, suggesting a hollow, rather than solid, cone in the velocity space of the ejected material. Opposite blue- and redshifts on the two sides of the prominence exhibit corkscrew variations both in space and time, suggestive of unwinding rotations of a left-handed helical flux rope. Some erupted material returns as nearly streamline flows, exhibiting distinctly narrow line widths (~10 km/s), about 50% of those of the nearby coronal rain at the apexes of coronal loops, where the rain material is initially formed out of cooling condensation. We estimate the mass and kinetic energy of the ejected and returning material and compare them with those of the associated CME. We will discuss the implications of these observations for CME initiation mechanisms.

Cancer risks after radiation exposure in middle age.

PubMed

Shuryak, Igor; Sachs, Rainer K; Brenner, David J

2010-11-03

Epidemiological data show that radiation exposure during childhood is associated with larger cancer risks compared with exposure at older ages. For exposures in adulthood, however, the relative risks of radiation-induced cancer in Japanese atomic bomb survivors generally do not decrease monotonically with increasing age of adult exposure. These observations are inconsistent with most standard models of radiation-induced cancer, which predict that relative risks decrease monotonically with increasing age at exposure, at all ages. We analyzed observed cancer risk patterns as a function of age at exposure in Japanese atomic bomb survivors by using a biologically based quantitative model of radiation carcinogenesis that incorporates both radiation induction of premalignant cells (initiation) and radiation-induced promotion of premalignant damage. This approach emphasizes the kinetics of radiation-induced initiation and promotion, and tracks the yields of premalignant cells before, during, shortly after, and long after radiation exposure. Radiation risks after exposure in younger individuals are dominated by initiation processes, whereas radiation risks after exposure at later ages are more influenced by promotion of preexisting premalignant cells. Thus, the cancer site-dependent balance between initiation and promotion determines the dependence of cancer risk on age at radiation exposure. For example, in terms of radiation induction of premalignant cells, a quantitative measure of the relative contribution of initiation vs promotion is 10-fold larger for breast cancer than for lung cancer. Reflecting this difference, radiation-induced breast cancer risks decrease with age at exposure at all ages, whereas radiation-induced lung cancer risks do not. For radiation exposure in middle age, most radiation-induced cancer risks do not, as often assumed, decrease with increasing age at exposure. This observation suggests that promotional processes in radiation carcinogenesis become increasingly important as the age at exposure increases. Radiation-induced cancer risks after exposure in middle age may be up to twice as high as previously estimated, which could have implications for occupational exposure and radiological imaging.

Chlorine atom-initiated low-temperature oxidation of prenol and isoprenol: The effect of C=C double bonds on the peroxy radical chemistry in alcohol oxidation

DOE PAGES

Welz, Oliver; Savee, John D.; Osborn, David L.; ...

2014-07-04

The chlorine atom-initiated oxidation of two unsaturated primary C5 alcohols, prenol (3-methyl-2-buten-1-ol, (CH 3) 2CCHCH 2OH) and isoprenol (3-methyl-3-buten-1-ol, CH 2C(CH 3)CH 2CH 2OH), is studied at 550 K and low pressure (8 Torr). The time- and isomer-resolved formation of products is probed with multiplexed photoionization mass spectrometry (MPIMS) using tunable vacuum ultraviolet ionizing synchrotron radiation. The peroxy radical chemistry of the unsaturated alcohols appears much less rich than that of saturated C4 and C5 alcohols. The main products observed are the corresponding unsaturated aldehydes – prenal (3-methyl-2-butenal) from prenol oxidation and isoprenal (3-methyl-3-butenal) from isoprenol oxidation. No significant productsmore » arising from QOOH chemistry are observed. These results can be qualitatively explained by the formation of resonance stabilized allylic radicals via H-abstraction in the Cl + prenol and Cl + isoprenol initiation reactions. The loss of resonance stabilization upon O 2 addition causes the energies of the intermediate wells, saddle points, and products to increase relative to the energy of the initial radicals and O 2. These energetic shifts make most product channels observed in the peroxy radical chemistry of saturated alcohols inaccessible for these unsaturated alcohols. The experimental findings are underpinned by quantum-chemical calculations for stationary points on the potential energy surfaces for the reactions of the initial radicals with O 2. Under our conditions, the dominant channels in prenol and isoprenol oxidation are the chain-terminating HO 2-forming channels arising from radicals, in which the unpaired electron and the –OH group are on the same carbon atom, with stable prenal and isoprenal co-products, respectively. These results suggest that the presence of C=C double bonds in alcohols will reduce low-temperature reactivity during autoignition.« less

Rainfall Morphology in Semi-Tropical Convergence Zones

NASA Technical Reports Server (NTRS)

Shepherd, J. Marshall; Ferrier, Brad S.; Ray, Peter S.

2000-01-01

Central Florida is the ideal test laboratory for studying convergence zone-induced convection. The region regularly experiences sea breeze fronts and rainfall-induced outflow boundaries. The focus of this study is the common yet poorly-studied convergence zone established by the interaction of the sea breeze front and an outflow boundary. Previous studies have investigated mechanisms primarily affecting storm initiation by such convergence zones. Few have focused on rainfall morphology yet these storms contribute a significant amount precipitation to the annual rainfall budget. Low-level convergence and mid-tropospheric moisture have both been shown to correlate with rainfall amounts in Florida. Using 2D and 3D numerical simulations, the roles of low-level convergence and mid-tropospheric moisture in rainfall evolution are examined. The results indicate that time-averaged, vertical moisture flux (VMF) at the sea breeze front/outflow convergence zone is directly and linearly proportional to initial condensation rates. This proportionality establishes a similar relationship between VMF and initial rainfall. Vertical moisture flux, which encompasses depth and magnitude of convergence, is better correlated to initial rainfall production than surface moisture convergence. This extends early observational studies which linked rainfall in Florida to surface moisture convergence. The amount and distribution of mid-tropospheric moisture determines how rainfall associated with secondary cells develop. Rainfall amount and efficiency varied significantly over an observable range of relative humidities in the 850- 500 mb layer even though rainfall evolution was similar during the initial or "first-cell" period. Rainfall variability was attributed to drier mid-tropospheric environments inhibiting secondary cell development through entrainment effects. Observationally, 850-500 mb moisture structure exhibits wider variability than lower level moisture, which is virtually always present in Florida. A likely consequence of the variability in 850-500 moisture is a stronger statistical correlation to rainfall, which observational studies have noted. The study indicates that vertical moisture flux forcing at convergence zones is critical in determining rainfall in the initial stage of development but plays a decreasing role in rainfall evolution as the system matures. The mid-tropospheric moisture (e.g. environment) plays an increasing role in rainfall evolution as the system matures. This suggests the need to improve measurements of magnitude/depth of convergence and mid-tropospheric moisture distribution. It also highlights the need for better parameterization of entrainment and vertical moisture distribution in larger-scale models.

Terrestrial gamma-ray flash production by lightning

NASA Astrophysics Data System (ADS)

Carlson, Brant E.

Terrestrial gamma-ray flashes (TGFs) are brief flashes of gamma-rays originating in the Earth's atmosphere and observed by satellites. First observed in 1994 by the Burst And Transient Source Experiment on board the Compton Gamma-Ray Observatory, TGFs consist of one or more ˜1 ms pulses of gamma-rays with a total fluence of ˜1/cm2, typically observed when the satellite is near active thunderstorms. TGFs have subsequently been observed by other satellites to have a very hard spectrum (harder than dN/d E ∝ 1/ E ) that extends from below 25 keV to above 20 MeV. When good lightning data exists, TGFs are closely associated with measurable lightning discharge. Such discharges are typically observed to occur within 300 km of the sub-satellite point and within several milliseconds of the TGF observation. The production of these intense energetic bursts of photons is the puzzle addressed herein. The presence of high-energy photons implies a source of bremsstrahlung, while bremsstrahlung implies a source of energetic electrons. As TGFs are associated with lightning, fields produced by lightning are naturally suggested to accelerate these electrons. Initial ideas about TGF production involved electric fields high above thunderstorms as suggested by upper atmospheric lightning research and the extreme energies required for lower-altitude sources. These fields, produced either quasi-statically by charges in the cloud and ionosphere or dynamically by radiation from lightning strokes, can indeed drive TGF production, but the requirements on the source lightning are too extreme and therefore not common enough to account for all existing observations. In this work, studies of satellite data, the physics of energetic electron and photon production, and consideration of lightning physics motivate a new mechanism for TGF production by lightning current pulses. This mechanism is then developed and used to make testable predictions. TGF data from satellite observations are compared to the results of Monte Carlo simulations of the physics of energetic photon production and propagation in air. These comparisons are used to constrain the TGF source altitude, energy, and directional distribution, and indicate a broadly-beamed low-altitude source inconsistent with production far above thunderstorms as previously suggested. The details of energetic electron production by electric fields in air are then examined. In particular, the source of initial high-energy electrons that are accelerated and undergo avalanche multiplication to produce bremsstrahlung is studied and the properties of these initial seed particles as produced by cosmic rays are determined. The number of seed particles available indicates either extremely large amplification of the number of seed particles or an alternate source of seeds. The low-altitude photon source and alternate source of seed particles required by these studies suggest a production mechanism closely-associated with lightning. A survey of lightning physics in the context of TGF emission indicates that current pulses along lightning channels may trigger TGF production by both producing strong electric fields and a large population of candidate seed electrons. The constraints on lightning physics, thunderstorm physics, and TGF physics all allow production by this mechanism. A computational model of this mechanism is then presented on the basis of a method of moments simulation of charge and current on a lightning channel. Calculation of the nearby electric fields then drives Monte Carlo simulations of energetic electron dynamics which determine the properties of the resulting bremsstrahlung. The results of this model compare quite well with satellite observations of TGFs subject to requirements on the ambient electric field and the current pulse magnitude and duration. The model makes quantitative predictions about the TGF source altitude, directional distribution, and lightning association that are in overall agreement with existing TGF observations and may be tested in more detail in future experiments.

Rapid ionization of the environment of SN 1987A

NASA Technical Reports Server (NTRS)

Raga, A. C.

1987-01-01

It has been suggested by some authors that IUE observations of the supernova SN 1987A show the presence of a strong component of the interstellar C IV 1550 and Si IV 1393 absorption lines at a velocity that approximately corresponds to the velocity of the LMC. It is possible that this component might come from originally neutral (or at least not very highly ionized) gas which has been photoionized by the initially very strong ionizing radiation field of the supernova. Theoretical considerations of this scenario lead to the study of fast (with velocities of about c) ionization fronts. It is shown that for reasonable model parameters it is possible to obtain considerably large C IV column densities, in agreement with the IUE observations. On the other hand, the models do not so easily predict the large Si IV column densities that are also obtained from the IUE observations. It is found that only models in which the interstellar medium surrounding SN 1987A is initially composed of already ionized hydrogen and helium predict substantial Si IV column densities. This result provides an interesting prediction of the ionization state of the environment of the presupernova star.

Polycystic ovarian disease unmasked by pulsatile GnRH therapy in a subgroup of women with hypothalamic amenorrhea.

PubMed

Mattle, Verena; Bilgyicildirim, Aysen; Hadziomerovic, Dijana; Ott, Helmut W; Zervomanolakis, Ioannis; Leyendecker, Gerhard; Wildt, Ludwig

2008-02-01

To present the observation in six out of 120 women treated with pulsatile GnRH for ovulation induction, who developed hyperandrogenemia and polycystic ovaries during treatment. Clinical observation. Department of Gynecologic Endocrinology and Reproductive Medicine, Medical University of Innsbruck, Austria. A total of 120 women initially diagnosed as suffering from primary or secondary hypothalamic amenorrhea were treated for ovulation induction with pulsatile administration of GnRH for up to 140 days. There was no indication of the presence of polycystic ovaries or hyperandrogenemia before therapy. Pulsatile GnRH therapy using the Zyklomat pump. Ovulatory menstrual cycles. Initially, all patients responded to pulsatile GnRH administration with ovulation and corpus luteum formation. During continuation of treatment, 6 patients developed an increase in LH and LH/FSH ratio as well as a progressive rise in serum T levels resulting in hyperandrogenemia. This was accompanied by the development of polycystic ovaries and cessation of follicular maturation. We conclude from these observations that restoration of normal GnRH stimulation of the pituitary gland can result in the development of hyperandrogenemia and polycystic ovaries, suggesting a pituitary or ovarian defect underlying the pathogenesis of this disorder.

A Multifunctional Mesothelin Antibody-tagged Microparticle Targets Human Mesotheliomas

PubMed Central

Macura, Sherrill L.; Hillegass, Jedd M.; Steinbacher, Jeremy L.; MacPherson, Maximilian B.; Shukla, Arti; Beuschel, Stacie L.; Perkins, Timothy N.; Butnor, Kelly J.; Lathrop, Melissa J.; Sayan, Mutlay; Hekmatyar, Khan; Taatjes, Douglas J.; Kauppinen, Risto A.; Landry, Christopher C.

2012-01-01

Pleural and peritoneal mesotheliomas (MMs) are chemoresistant tumors with no effective therapeutic strategies. The authors first injected multifunctional, acid-prepared mesoporous spheres (APMS), microparticles functionalized with tetraethylene glycol oligomers, intraperitoneally into rodents. Biodistribution of APMS was observed in major organs, peritoneal lavage fluid (PLF), and urine of normal mice and rats. After verification of increased mesothelin in human mesotheliomas injected into severe combined immunodeficient (SCID) mice, APMS were then functionalized with an antibody to mesothelin (APMS-MB) or bovine serum albumin (BSA), a nonspecific protein control, and tumor targeting was evaluated by inductively coupled plasma mass spectrometry and multifluorescence confocal microscopy. Some APMS were initially cleared via the urine over a 24 hr period, and small amounts were observed in liver, spleen, and kidneys at 24 hr and 6 days. Targeting with APMS-MB increased APMS uptake in mesenteric tumors at 6 days. Approximately 10% to 12% of the initially injected amount was observed in both spheroid and mesenteric MM at this time point. The data suggest that localized delivery of APMS-MB into the peritoneal cavity after encapsulation of drugs, DNA, or macromolecules is a novel therapeutic approach for MM and other tumors (ovarian and pancreatic) that overexpress mesothelin. PMID:22723527

A more direct measure of supernova rates in starburst galaxies

NASA Technical Reports Server (NTRS)

Van Buren, Dave; Greenhouse, Matthew A.

1994-01-01

We determine ages for young supernova remnants in the starburst galaxies M82 and NGC 253 by applying Chevalier's model for radio emission from supernova blast waves expanding into the ejecta of their precursor stars. Absolute ages are determined by calibrating the model with radio observations of Cas A. We derive supernova rates of 0.10 and 0.08/yr for M82 and NGC 253, respectively. Assuming L (sub FIR) to be proportional to the supernova rate, we find r(sub SN) approximately equal 2 x 10(exp -12) x L(sub FIR), solar yr(exp -1) for these archetypal starburst galaxies. This approach is unique in that the supernova rate is derived from direct observation of supernova remnants rather than from star formation rates and an assumed initial mass function (IMF). We suggest that the approach presented here can be used to derive star-formation rates that are more directly related to observable quantities than those derived by other methods. We find that the supernova rate, far infrared (FIR) luminosity, and dynamical mass of the M82 starburst place few constraints on the initial mass function (IMF) slope and mass limits.

Bianchi type string cosmological models in f(R,T) gravity

NASA Astrophysics Data System (ADS)

Sahoo, P. K.; Mishra, B.; Sahoo, Parbati; Pacif, S. K. J.

2016-09-01

In this work we have studied Bianchi-III and - VI 0 cosmological models with string fluid source in f( R, T) gravity (T. Harko et al., Phys. Rev. D 84, 024020 (2011)), where R is the Ricci scalar and T the trace of the stress energy-momentum tensor in the context of late time accelerating expansion of the universe as suggested by the present observations. The exact solutions of the field equations are obtained by using a time-varying deceleration parameter. The universe is anisotropic and free from initial singularity. Our model initially shows acceleration for a certain period of time and then decelerates consequently. Several dynamical and physical behaviors of the model are also discussed in detail.

Social interactions of students with disabilities who use augmentative and alternative communication in inclusive classrooms.

PubMed

Chung, Yun-Ching; Carter, Erik W; Sisco, Lynn G

2012-09-01

The purpose of this study was to explore the naturally occurring social interactions for students with disabilities who use augmentative and alternative communication (AAC) in general education classrooms. We observed 16 students who used AAC and received services under the categories of autism or intellectual disability. Participants primarily interacted with their support personnel and infrequently conversed with peers despite often being in close proximity. Few interaction episodes were initiated by students who used AAC, and initiations to peers and adults appeared to serve somewhat different functions. Students with disabilities relied more heavily on facial expressions and gestures than on the use of their AAC devices. Recommendations for promoting interaction opportunities among students are offered, and future research directions are suggested.

Delayed post-hypoxic leukoencephalopathy: case report with a review of disease pathophysiology.

PubMed

Meyer, Michael Andrew

2013-01-01

Delayed post-hypoxic leukoencephalopathy is a rare clinical phenomenon usually observed in a small number of carbon monoxide poisoning survivors. A similar phenomenon is reported here in a patient who successfully recovered from a large overdose of diazepam and methadone, but then abruptly declined 3 weeks after the initial event. Magnetic resnance revealed confluent white matter hyperintensity on fluid-attenuated inversion recovery and T2 weighted sequences, and spectroscopy revealed elevated peaks in choline, creatinine, and lactate. Analysis and review of the literature suggests this phenomenon occurs on average about 19 days after the initial event. Although the pathophysiology remains obscure, it is noted here that the mean lucid interval coincides approximately with the replacement half-life for myelin related lipids and proteins.

Dynamical evolution of dense star clusters in galactic nuclei

NASA Astrophysics Data System (ADS)

Haas, Jaroslav; Šubr, Ladislav

2014-05-01

By means of direct numerical N-body modeling, we investigate the orbital evolution of an initially thin, central mass dominated stellar disk. We include the perturbative gravitational influence of an extended spherically symmetric star cluster and the mutual gravitational interaction of the stars within the disk. Our results show that the two-body relaxation of the disk leads to significant changes of its radial density profile. In particular, the disk naturally evolves, for a variety of initial configurations, a similar broken power-law surface density profile. Hence, it appears that the single power-law surface density profile ∝R -2 suggested by various authors to describe the young stellar disk observed in the Sgr A* region does not match theoretical expectations.

Application of ground-penetrating radar at McMurdo Station, Antarctica

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

Stefano, J.E.

1992-05-01

Argonne National Laboratory initiated a site investigation program at McMurdo Station, Antarctica, to characterize environmental contamination. The performance and usefulness of ground-penetrating radar (GPR) was evaluated under antarctic conditions during the initial site investigation in January 1991. Preliminary surveys were successful in defining the contact between reworked pyroclastic material and in the prefill, undisturbed pyroclastics and basalts at some sites. Interference from radio traffic at McMurdo Station was not observed, but interference was a problem in work with unshielded antennas near buildings. In general, the results of this field test suggest that high-quality, high-resolution, continuous subsurface profiles can be producedmore » with GPR over most of McMurdo Station.« less

Application of ground-penetrating radar at McMurdo Station, Antarctica

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

Stefano, J.E.

1992-01-01

Argonne National Laboratory initiated a site investigation program at McMurdo Station, Antarctica, to characterize environmental contamination. The performance and usefulness of ground-penetrating radar (GPR) was evaluated under antarctic conditions during the initial site investigation in January 1991. Preliminary surveys were successful in defining the contact between reworked pyroclastic material and in the prefill, undisturbed pyroclastics and basalts at some sites. Interference from radio traffic at McMurdo Station was not observed, but interference was a problem in work with unshielded antennas near buildings. In general, the results of this field test suggest that high-quality, high-resolution, continuous subsurface profiles can be producedmore » with GPR over most of McMurdo Station.« less

Evolution of Wernicke-Korsakoff syndrome in self-neglecting alcoholics: preliminary results of relation with Wernicke-delirium and diabetes mellitus.

PubMed

Wijnia, Jan W; van de Wetering, Ben J M; Zwart, Elles; Nieuwenhuis, K Gerrit A; Goossensen, M Anne

2012-01-01

We present a descriptive, retrospective study of initial symptoms, comorbidity, and alcohol withdrawal in 73 alcoholic patients with subsequent Korsakoff syndrome. In 25/73 (35%) of the patients the classic triad of Wernicke's encephalopathy with ocular symptoms, ataxia and confusion, was found. In at least 6/35 (17%) of the initial deliria (95% confidence interval: 10-25%) we observed no other underlying causes, thus excluding other somatic causes, medication, (recent) alcohol withdrawal, or intoxication. We suggest that these deliria may have been representing Wernicke's encephalopathy. A high frequency (15%) of diabetics may reflect a contributing factor of diabetes mellitus in the evolution of the Wernicke-Korsakoff syndrome. Copyright © American Academy of Addiction Psychiatry.

Seasonal variability of the hydrogen exosphere of Mars

NASA Astrophysics Data System (ADS)

Halekas, J. S.

2017-05-01

The Mars Atmosphere and Volatile EvolutioN (MAVEN) mission measures both the upstream solar wind and collisional products from energetic neutral hydrogen atoms that precipitate into the upper atmosphere after their initial formation by charge exchange with exospheric hydrogen. By computing the ratio between the densities of these populations, we derive a robust measurement of the column density of exospheric hydrogen upstream of the Martian bow shock. By comparing with Chamberlain-type model exospheres, we place new constraints on the structure and escape rates of exospheric hydrogen, derived from observations sensitive to a different and potentially complementary column from most scattered sunlight observations. Our observations provide quantitative estimates of the hydrogen exosphere with nearly complete temporal coverage, revealing order of magnitude seasonal changes in column density and a peak slightly after perihelion, approximately at southern summer solstice. The timing of this peak suggests either a lag in the response of the Martian atmosphere to solar inputs or a seasonal effect driven by lower atmosphere dynamics. The high degree of seasonal variability implied by our observations suggests that the Martian atmosphere and the thermal escape of light elements depend sensitively on solar inputs.

Investigation of random walks knee cartilage segmentation model using inter-observer reproducibility: Data from the osteoarthritis initiative.

PubMed

Hong-Seng, Gan; Sayuti, Khairil Amir; Karim, Ahmad Helmy Abdul

2017-01-01

Existing knee cartilage segmentation methods have reported several technical drawbacks. In essence, graph cuts remains highly susceptible to image noise despite extended research interest; active shape model is often constraint by the selection of training data while shortest path have demonstrated shortcut problem in the presence of weak boundary, which is a common problem in medical images. The aims of this study is to investigate the capability of random walks as knee cartilage segmentation method. Experts would scribble on knee cartilage image to initialize random walks segmentation. Then, reproducibility of the method is assessed against manual segmentation by using Dice Similarity Index. The evaluation consists of normal cartilage and diseased cartilage sections which is divided into whole and single cartilage categories. A total of 15 normal images and 10 osteoarthritic images were included. The results showed that random walks method has demonstrated high reproducibility in both normal cartilage (observer 1: 0.83±0.028 and observer 2: 0.82±0.026) and osteoarthritic cartilage (observer 1: 0.80±0.069 and observer 2: 0.83±0.029). Besides, results from both experts were found to be consistent with each other, suggesting the inter-observer variation is insignificant (Normal: P=0.21; Diseased: P=0.15). The proposed segmentation model has overcame technical problems reported by existing semi-automated techniques and demonstrated highly reproducible and consistent results against manual segmentation method.

Ultra-fast movies of thin-film laser ablation

NASA Astrophysics Data System (ADS)

Domke, Matthias; Rapp, Stephan; Schmidt, Michael; Huber, Heinz P.

2012-11-01

Ultra-short-pulse laser irradiation of thin molybdenum films from the glass substrate side initiates an intact Mo disk lift off free from thermal effects. For the investigation of the underlying physical effects, ultra-fast pump-probe microscopy is used to produce stop-motion movies of the single-pulse ablation process, initiated by a 660-fs laser pulse. The ultra-fast dynamics in the femtosecond and picosecond ranges are captured by stroboscopic illumination of the sample with an optically delayed probe pulse of 510-fs duration. The nanosecond and microsecond delay ranges of the probe pulse are covered by an electronically triggered 600-ps laser. Thus, the setup enables an observation of general laser ablation processes from the femtosecond delay range up to the final state. A comparison of time- and space-resolved observations of film and glass substrate side irradiation of a 470-nm molybdenum layer reveals the driving mechanisms of the Mo disk lift off initiated by glass-side irradiation. Observations suggest that a phase explosion generates a liquid-gas mixture in the molybdenum/glass interface about 10 ps after the impact of the pump laser pulse. Then, a shock wave and gas expansion cause the molybdenum layer to bulge, while the enclosed liquid-gas mixture cools and condenses at delay times in the 100-ps range. The bulging continues for approximately 20 ns, when an intact Mo disk shears and lifts off at a velocity of above 70 m/s. As a result, the remaining hole is free from thermal effects.

The effects of task difficulty on visual search strategy in virtual 3D displays

PubMed Central

Pomplun, Marc; Garaas, Tyler W.; Carrasco, Marisa

2013-01-01

Analyzing the factors that determine our choice of visual search strategy may shed light on visual behavior in everyday situations. Previous results suggest that increasing task difficulty leads to more systematic search paths. Here we analyze observers' eye movements in an “easy” conjunction search task and a “difficult” shape search task to study visual search strategies in stereoscopic search displays with virtual depth induced by binocular disparity. Standard eye-movement variables, such as fixation duration and initial saccade latency, as well as new measures proposed here, such as saccadic step size, relative saccadic selectivity, and x−y target distance, revealed systematic effects on search dynamics in the horizontal-vertical plane throughout the search process. We found that in the “easy” task, observers start with the processing of display items in the display center immediately after stimulus onset and subsequently move their gaze outwards, guided by extrafoveally perceived stimulus color. In contrast, the “difficult” task induced an initial gaze shift to the upper-left display corner, followed by a systematic left-right and top-down search process. The only consistent depth effect was a trend of initial saccades in the easy task with smallest displays to the items closest to the observer. The results demonstrate the utility of eye-movement analysis for understanding search strategies and provide a first step toward studying search strategies in actual 3D scenarios. PMID:23986539

Hubble Space Telescope scale 3D simulations of MHD disc winds: a rotating two-component jet structure

NASA Astrophysics Data System (ADS)

Staff, J. E.; Koning, N.; Ouyed, R.; Thompson, A.; Pudritz, R. E.

2015-02-01

We present the results of large scale, three-dimensional magnetohydrodynamics simulations of disc winds for different initial magnetic field configurations. The jets are followed from the source to 90 au scale, which covers several pixels of Hubble Space Telescope images of nearby protostellar jets. Our simulations show that jets are heated along their length by many shocks. We compute the emission lines that are produced, and find excellent agreement with observations. The jet width is found to be between 20 and 30 au while the maximum velocities perpendicular to the jet are found to be up to above 100 km s-1. The initially less open magnetic field configuration simulations result in a wider, two-component jet; a cylindrically shaped outer jet surrounding a narrow and much faster, inner jet. These simulations preserve the underlying Keplerian rotation profile of the inner jet to large distances from the source. However, for the initially most open magnetic field configuration the kink mode creates a narrow corkscrew-like jet without a clear Keplerian rotation profile and even regions where we observe rotation opposite to the disc (counter-rotating). The RW Aur jet is narrow, indicating that the disc field in that case is very open meaning the jet can contain a counter-rotating component that we suggest explains why observations of rotation in this jet have given confusing results. Thus magnetized disc winds from underlying Keplerian discs can develop rotation profiles far down the jet that is not Keplerian.

Mechanical perturbation-induced ethylene releases apical dominance in Pharbitis nil by restricting shoot growth

NASA Technical Reports Server (NTRS)

Prasad, T. K.; Cline, M. G.

1985-01-01

Mechanical perturbation (MP, rubbing) or internodes of Pharbitis nil shoots initiates release of lateral buds (LB) from apical dominance within 48 h. Evidence is presented which suggests that MP promotion of LB outgrowth is mediated by ethylene-induced restriction of main shoot growth. Ethylene production in the internodes is stimulated by MP within 2 h. Effects of MP are mimicked by treatments with 1-aminocyclopropane-1-carboxylic acid (ACC) and are negated by the inhibitors of ethylene production or action, aminoethoxy vinylglycine (AVG) and AgNO3. The fact that effects of MP, ACC, and ethylene inhibitors are observed to occur on main shoot growth at least 24 h before they are observed to occur on LB growth suggests a possible cause and effect relationship. MP also causes an increase in internode diameter. MP stimulation of ethylene production appears to be mediated by ACC synthase. The results of this study and our previous studies suggest that apical dominance may be released by any mechanism which induces ethylene restriction of main shoot growth.

Post audit of a numerical prediction of wellfield drawdown in a semiconfined aquifer system

USGS Publications Warehouse

Stewart, M.; Langevin, C.

1999-01-01

A numerical ground water flow model was created in 1978 and revised in 1981 to predict the drawdown effects of a proposed municipal wellfield permitted to withdraw 30 million gallons per day (mgd; 1.1 x 105 m3/day) of water from the semiconfined Floridan Aquifer system. The predictions are based on the assumption that water levels in the semiconfined Floridan Aquifer reach a long-term, steady-state condition within a few days of initiation of pumping. Using this assumption, a 75 day simulation without water table recharge, pumping at the maximum permitted rates, was considered to represent a worst-case condition and the greatest drawdowns that could be experienced during wellfield operation. This method of predicting wellfield effects was accepted by the permitting agency. For this post audit, observed drawdowns were derived by taking the difference between pre-pumping and post-pumping potentiometric surface levels. Comparison of predicted and observed drawdowns suggests that actual drawdown over a 12 year period exceeds predicted drawdown by a factor of two or more. Analysis of the source of error in the 1981 predictions suggests that the values used for transmissivity, storativity, specific yield, and leakance are reasonable at the wellfield scale. Simulation using actual 1980-1992 pumping rates improves the agreement between predicted and observed drawdowns. The principal source of error is the assumption that water levels in a semiconfined aquifer achieve a steady-state condition after a few days or weeks of pumping. Simulations using a version of the 1981 model modified to include recharge and evapotranspiration suggest that it can take hundreds of days or several years for water levels in the linked Surficial and Floridan Aquifers to reach an apparent steady-state condition, and that slow declines in levels continue for years after the initiation of pumping. While the 1981 'impact' model can be used for reasonably predicting short-term, wellfield-scale effects of pumping, using a 75 day long simulation without recharge to predict the long-term behavior of the wellfield was an inappropriate application, resulting in significant underprediction of wellfield effects.A numerical ground water flow model was created in 1978 and revised in 1981 to predict the drawdown effects of a proposed municipal wellfield permitted to withdraw 30 million gallons per day (mgd; 1.1??105 m3/day) of water from the semiconfined Floridan Aquifer system. The predictions are based on the assumption that water levels in the semiconfined Floridan Aquifer reach a long-term, steady-state condition within a few days of initiation of pumping. Using this assumption, a 75 day simulation without water table recharge, pumping at the maximum permitted rates, was considered to represent a worst-case condition and the greatest drawdowns that could be experienced during wellfield operation. This method of predicting wellfield effects was accepted by the permitting agency. For this post audit, observed drawdowns were derived by taking the difference between pre-pumping and post-pumping potentiometric surface levels. Comparison of predicted and observed drawdowns suggests that actual drawdown over a 12 year period exceeds predicted drawdown by a factor of two or more. Analysis of the source of error in the 1981 predictions suggests that the values used for transmissivity, storativity, specific yield, and leakance are reasonable at the wellfield scale. Simulation using actual 1980-1992 pumping rates improves the agreement between predicted and observed drawdowns. The principal source of error is the assumption that water levels in a semiconfined aquifer achieve a steady-state condition after a few days or weeks of pumping. Simulations using a version of the 1981 model modified to include recharge and evapotranspiration suggest that it can take hundreds of days or several years for water levels in the linked Surficial and Floridan Aquifers to reach an apparent stead

Tissue-specific profile of DNA replication in the swimming larvae of Ciona intestinalis.

PubMed

Nakayama, Akie; Satoh, Nori; Sasakura, Yasunori

2005-03-01

The cell cycle is strictly regulated during development and its regulation is essential for organ formation and developmental timing. Here we observed the pattern of DNA replication in swimming larvae of an ascidian, Ciona intestinalis. Usually, Ciona swimming larvae obtain competence for metamorphosis at about 4-5 h after hatching, and these competent larvae initiate metamorphosis soon after they adhere to substrate with their papillae. In these larvae, three major tissues (epidermis, endoderm and mesenchyme) showed extensive DNA replication with distinct pattern and timing, suggesting tissue-specific cell cycle regulation. However, DNA replication did not continue in aged larvae which kept swimming for several days, suggesting that the cell cycle is arrested in these larvae at a certain time to prevent further growth of adult organ rudiments until the initiation of metamorphosis. Inhibition of the cell cycle by aphidicolin during the larval stage affects only the speed of metamorphosis, and not the formation of adult organ rudiments or the timing of the initiation of metamorphosis. However, after the completion of tail resorption, DNA replication is necessary for further metamorphic events. Our data showed that DNA synthesis in the larval trunk is not directly associated with the organization of adult organs, but it contributes to the speed of metamorphosis after settlement.

The RepA_N replicons of Gram-positive bacteria: a family of broadly distributed but narrow host range plasmids.

PubMed

Weaver, Keith E; Kwong, Stephen M; Firth, Neville; Francia, Maria Victoria

2009-03-01

The pheromone-responsive conjugative plasmids of Enterococcus faecalis and the multiresistance plasmids pSK1 and pSK41 of Staphylococcus aureus are among the best studied plasmids native to Gram-positive bacteria. Although these plasmids seem largely restricted to their native hosts, protein sequence comparison of their replication initiator proteins indicates that they are clearly related. Homology searches indicate that these replicons are representatives of a large family of plasmids and a few phage that are widespread among the low G+C Gram-positive bacteria. We propose to name this family the RepA_N family of replicons after the annotated conserved domain that the initiator protein contains. Detailed sequence comparisons indicate that the initiator protein phylogeny is largely congruent with that of the host, suggesting that the replicons have evolved along with their current hosts and that intergeneric transfer has been rare. However, related proteins were identified on chromosomal regions bearing characteristics indicative of ICE elements, and the phylogeny of these proteins displayed evidence of more frequent intergeneric transfer. Comparison of stability determinants associated with the RepA_N replicons suggests that they have a modular evolution as has been observed in other plasmid families.

The RepA_N replicons of Gram-positive bacteria: a family of broadly distributed but narrow host range plasmids

PubMed Central

Weaver, Keith E.; Kwong, Stephen M.; Firth, Neville; Francia, Maria Victoria

2009-01-01

The pheromone-responsive conjugative plasmids of Enterococcus faecalis and the multi-resistance plasmids pSK1 and pSK41 of Staphylococcus aureus are among the best studied plasmids native to Gram-positive bacteria. Although these plasmids seem largely restricted to their native hosts, protein sequence comparison of their replication initiator proteins indicates that they are clearly related. Homology searches indicate that these replicons are representatives of a large family of plasmids and a few phage that are widespread among the low G+C Gram-positive bacteria. We propose to name this family the RepA_N family of replicons after the annotated conserved domain that the initiator protein contains. Detailed sequence comparisons indicate that the initiator protein phylogeny is largely congruent with that of the host, suggesting that the replicons have evolved along with their current hosts and that intergeneric transfer has been rare. However, related proteins were identified on chromosomal regions bearing characteristics indicative of ICE elements, and the phylogeny of these proteins displayed evidence of more frequent intergeneric transfer. Comparison of stability determinants associated with the RepA_N replicons suggests that they have a modular evolution as has been observed in other plasmid families. PMID:19100285

Distinct dynamic profiles of microglial activation are associated with progression of Alzheimer's disease.

PubMed

Hamelin, Lorraine; Lagarde, Julien; Dorothée, Guillaume; Potier, Marie Claude; Corlier, Fabian; Kuhnast, Bertrand; Caillé, Fabien; Dubois, Bruno; Fillon, Ludovic; Chupin, Marie; Bottlaender, Michel; Sarazin, Marie

2018-06-01

Although brain neuroinflammation may play an instrumental role in the pathophysiology of Alzheimer's disease, its actual impact on disease progression remains controversial, being reported as either detrimental or protective. This work aimed at investigating the temporal relationship between microglial activation and clinical progression of Alzheimer's disease. First, in a large cohort of patients with Alzheimer's disease we analysed the predictive value of microglial activation assessed by 18F-DPA-714 PET imaging on functional, cognitive and MRI biomarkers outcomes after a 2-year follow-up. Second, we analysed the longitudinal progression of 18F-DPA-714 binding in patients with Alzheimer's disease by comparison with controls, and assessed its influence on clinical progression. At baseline, all participants underwent a clinical assessment, brain MRI, 11C-PiB, 18F-DPA-714 PET imaging and TSPO genotyping. Participants were followed-up annually for 2 years. At the end of the study, subjects were asked to repeat a second 18F-DPA-714-PET imaging. Initial 18F-DPA-714 binding was higher in prodromal (n = 33) and in demented patients with Alzheimer's disease (n = 19) compared to controls (n = 17). After classifying patients into slow and fast decliners according to functional (Clinical Dementia Rating change) or cognitive (Mini-Mental State Examination score decline) outcomes, we found a higher initial 18F-DPA-714 binding in slow than fast decliners. Negative correlations were observed between initial 18F-DPA-714 binding and the Clinical Dementia Rating Sum of Boxes score increase, the MMSE score loss and the progression of hippocampal atrophy. This suggests that higher initial 18F-DPA-714 binding is associated with better clinical prognosis. Twenty-four patients with Alzheimer's disease and 15 control subjects performed a second DPA-PET. We observed an increase of 18F-DPA-714 in patients with Alzheimer's disease as compared with controls (mean 13.2% per year versus 4.2%) both at the prodromal (15.8%) and at the demented stages (8.3%). The positive correlations between change in 18F-DPA-714 binding over time and the three clinical outcome measures (Clinical Dementia Rating, Mini-Mental State Examination, hippocampal atrophy) suggested a detrimental effect on clinical Alzheimer's disease progression of increased neuroinflammation after the initial PET examination, without correlation with PiB-PET uptake at baseline. High initial 18F-DPA-714 binding was correlated with a low subsequent increase of microglial activation and favourable clinical evolution, whereas the opposite profile was observed when initial 18F-DPA-714 binding was low, independently of disease severity at baseline. Taken together, our results support a pathophysiological model involving two distinct profiles of microglial activation signatures with different dynamics, which differentially impact on disease progression and may vary depending on patients rather than disease stages.

The effect of cathodic polarization on the corrosion fatigue behavior of a precipitation hardened aluminum alloy

NASA Astrophysics Data System (ADS)

Smith, E. F.; Duquette, D. J.

1986-02-01

Fatigue experiments were conducted on polycrystalline and monocrystalline samples of a high purity Al, 5.5 wt pct Zn, 2.5 wt pct Mg, 1.5 wt pct Cu alloy in the peak-hardened heat treatment condition. These experiments were conducted in dry laboratory air and in 0.5 N NaCl solutions at the corrosion potential and at applied potentials cathodic to the corrosion potential. It has been shown that saline solutions severely reduce the fatigue resistance of the alloy, resulting in considerable amounts of intergranular crack initiation and propagation under freely corroding conditions for polycrystalline samples. Applied cathodic potentials resulted in still larger decreases in fatigue resistance and, for poly crystals, increases in the degree of transgranular crack initiation and propagation. Increasing amounts of intergranular cracking were observed when applied cyclic stresses were reduced (longer test times). The characteristics of cracking, combined with results obtained on tensile tests of deformed and hydrogen charged samples, suggest that environmental cracking of these alloys is associated with a form of hydrogen embrittlement of the process zones of growing cracks. Further, it is suggested that stress corrosion cracking and corrosion fatigue of these alloys occurs by essentially the same mechanism, but that the often observed transgranular cracking under cyclic loading conditions occurs due to enhanced hydrogen transport and/or concentrations associated with mobile dislocations at growing crack tips.

A comparison between two inundation models for the 25 Ooctober 2010 Mentawai Islands Tsunami

NASA Astrophysics Data System (ADS)

Huang, Z.; Borrero, J. C.; Qiu, Q.; Hill, E. M.; Li, L.; Sieh, K. E.

2011-12-01

On 25 October 2010, an Mw~7.8 earthquake occurred on the Sumatra megathrust seaward of the Mentawai Islands, Indonesia, generating a tsunami which killed approximately 500 people. Following the event, the Earth Observatory of Singapore (EOS) initiated a post-tsunami field survey, collecting tsunami run-up data from more than 30 sites on Pagai Selatan, Pagai Utara and Sipora. The strongest tsunami effects were observed on several small islands offshore of Pagai Selatan, where runup exceeded 16 m. This presentation will focus on a detailed comparison between two tsunami propagation and inundation models: COMCOT (Cornell Multi-grid Coupled Tsunami model) and MOST (Method of Splitting Tsunami). Simulations are initialized using fault models based on data from a 1-hz GPS system that measured co-seismic deformation throughout the region. Preliminary simulations suggest that 2-m vertical seafloor deformation over a reasonably large area is required to recreate most of the observed tsunami effects. Since the GPS data suggest that subsidence of the islands is small, this implies that the tsunami source region is somewhat narrower and located further offshore than described in recently published earthquake source models based on teleseismic inversions alone. We will also discuss issues such as bathymetric and topographic data preparation and the uncertainty in the modeling results due to the lack of high resolution bathymetry and topography in the study area.

Triggered creep as a possible mechanism for delayed dynamic triggering of tremor and earthquakes

USGS Publications Warehouse

Shelly, David R.; Peng, Zhigang; Hill, David P.; Aiken, Chastity

2011-01-01

The passage of radiating seismic waves generates transient stresses in the Earth's crust that can trigger slip on faults far away from the original earthquake source. The triggered fault slip is detectable in the form of earthquakes and seismic tremor. However, the significance of these triggered events remains controversial, in part because they often occur with some delay, long after the triggering stress has passed. Here we scrutinize the location and timing of tremor on the San Andreas fault between 2001 and 2010 in relation to distant earthquakes. We observe tremor on the San Andreas fault that is initiated by passing seismic waves, yet migrates along the fault at a much slower velocity than the radiating seismic waves. We suggest that the migrating tremor records triggered slow slip of the San Andreas fault as a propagating creep event. We find that the triggered tremor and fault creep can be initiated by distant earthquakes as small as magnitude 5.4 and can persist for several days after the seismic waves have passed. Our observations of prolonged tremor activity provide a clear example of the delayed dynamic triggering of seismic events. Fault creep has been shown to trigger earthquakes, and we therefore suggest that the dynamic triggering of prolonged fault creep could provide a mechanism for the delayed triggering of earthquakes. ?? 2011 Macmillan Publishers Limited. All rights reserved.

Dynamical origin of non-thermal states in galactic filaments

NASA Astrophysics Data System (ADS)

Di Cintio, Pierfrancesco; Gupta, Shamik; Casetti, Lapo

2018-03-01

Observations strongly suggest that filaments in galactic molecular clouds are in a non-thermal state. As a simple model of a filament, we study a two-dimensional system of self-gravitating point particles by means of numerical simulations of the dynamics, with various methods: direct N-body integration of the equations of motion, particle-in-cell simulations, and a recently developed numerical scheme that includes multiparticle collisions in a particle-in-cell approach. Studying the collapse of Gaussian overdensities, we find that after the damping of virial oscillations the system settles in a non-thermal steady state whose radial density profile is similar to the observed ones, thus suggesting a dynamical origin of the non-thermal states observed in real filaments. Moreover, for sufficiently cold collapses, the density profiles are anticorrelated with the kinetic temperature, i.e. exhibit temperature inversion, again a feature that has been found in some observations of filaments. The same happens in the state reached after a strong perturbation of an initially isothermal cylinder. Finally, we discuss our results in the light of recent findings in other contexts (including non-astrophysical ones) and argue that the same kind of non-thermal states may be observed in any physical system with long-range interactions.

Symmetry-breaking bifurcations and enhanced mixing in microfluidic cross-slots

NASA Astrophysics Data System (ADS)

Poole, Rob; Haward, Simon; Oliveira, Paulo; Alves, Manuel

2014-11-01

We investigate, both experimentally and numerically, a new subcritical bifurcation phenomenon for a Newtonian fluid flowing through three-dimensional cross-slot geometries. At low Reynolds numbers the flow remains steady and symmetric. For the case of square inlets and outlets, at a critical Reynolds number of approximately 40 (based on average velocity) a pitchfork bifurcation is observed beyond which the unstable symmetrical solution is replaced by a pair of steady asymmetric solutions. Sensitivity of this critical Reynolds number to the initial conditions of the simulation, resulting in a small degree of hysteresis, suggests a subcritical instability. At higher flowrates the flow becomes unsteady. The effects of channel aspect ratio are investigated on the critical conditions and excellent agreement is found between three-dimensional finite volume simulations and flow visualisation experiments in microfluidic channels. Finally we suggest this new flow bifurcation could be an effective method of enhancing mixing in microfluidic channels as significant increases in mixing quality are observed beyond the bifurcation. This enhancement occurs at flowrates more than a factor of two smaller than those observed in the well-known T-channel micromixer.

Polarization Signatures of Kink Instabilities in the Blazar Emission Region from Relativistic Magnetohydrodynamic Simulations

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

Zhang, Haocheng; Taylor, Greg; Li, Hui

Kink instabilities are likely to occur in the current-carrying magnetized plasma jets. Recent observations of the blazar radiation and polarization signatures suggest that the blazar emission region may be considerably magnetized. While the kink instability has been studied with first-principle magnetohydrodynamic (MHD) simulations, the corresponding time-dependent radiation and polarization signatures have not been investigated. In this paper, we perform comprehensive polarization-dependent radiation modeling of the kink instability in the blazar emission region based on relativistic MHD (RMHD) simulations. We find that the kink instability may give rise to strong flares with polarization angle (PA) swings or weak flares with polarizationmore » fluctuations, depending on the initial magnetic topology and magnetization. These findings are consistent with observations. Compared with the shock model, the kink model generates polarization signatures that are in better agreement with the general polarization observations. Therefore, we suggest that kink instabilities may widely exist in the jet environment and provide an efficient way to convert the magnetic energy and produce multiwavelength flares and polarization variations.« less

Polarization Signatures of Kink Instabilities in the Blazar Emission Region from Relativistic Magnetohydrodynamic Simulations

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

Zhang, Haocheng; Li, Hui; Guo, Fan

Kink instabilities are likely to occur in the current-carrying magnetized plasma jets. Recent observations of the blazar radiation and polarization signatures suggest that the blazar emission region may be considerably magnetized. While the kink instability has been studied with first-principle magnetohydrodynamic (MHD) simulations, the corresponding time-dependent radiation and polarization signatures have not been investigated. Here, in this paper, we perform comprehensive polarization-dependent radiation modeling of the kink instability in the blazar emission region based on relativistic MHD (RMHD) simulations. We find that the kink instability may give rise to strong flares with polarization angle (PA) swings or weak flares withmore » polarization fluctuations, depending on the initial magnetic topology and magnetization. These findings are consistent with observations. In addition, compared with the shock model, the kink model generates polarization signatures that are in better agreement with the general polarization observations. Therefore, we suggest that kink instabilities may widely exist in the jet environment and provide an efficient way to convert the magnetic energy and produce multiwavelength flares and polarization variations.« less

Developmental evaluation and the 'Stronger Economies Together' initiative in the United States.

PubMed

Honadle, Beth Walter; Zapata, Marisa A; Auffrey, Christopher; vom Hofe, Rainer; Looye, Johanna

2014-04-01

This article describes a developmental evaluation and explains its impact on the Stronger Economies Together (SET) initiative of the U.S. Department of Agriculture in collaboration with the Nation's four Regional Rural Development Centers and Land-Grant universities. Through a dynamic process, this evaluation of the early phases of an initiative led to continuous program alterations based on feedback. The relationship of the evaluation team to the initiative's coordinating team enabled seamless transfer of observations, suggestions, and recommendations to decision makers. The multidisciplinary character of the evaluation team provided a diverse set of perspectives with a depth of subject matter and knowledge from relevant fields. One lesson is that developmental evaluators must be flexible, nimble, creative, and adaptive. When expected data are imperfect or nonexistent, the team must collect alternate information and make recommendations to improve data collection. As the initiative proceeded and modifications came about, the evaluation team had to recognize the changes in the program and focus on different questions. This experience with developmental evaluation provides insights into how interdisciplinary teams may need to change course and conduct a developmental evaluation when a formative evaluation was originally envisioned. Published by Elsevier Ltd.

Decadal climate predictability in the southern Indian Ocean captured by SINTEX-F using a simple SST-nudging scheme.

PubMed

Morioka, Yushi; Doi, Takeshi; Behera, Swadhin K

2018-01-26

Decadal climate variability in the southern Indian Ocean has great influences on southern African climate through modulation of atmospheric circulation. Although many efforts have been made to understanding physical mechanisms, predictability of the decadal climate variability, in particular, the internally generated variability independent from external atmospheric forcing, remains poorly understood. This study investigates predictability of the decadal climate variability in the southern Indian Ocean using a coupled general circulation model, called SINTEX-F. The ensemble members of the decadal reforecast experiments were initialized with a simple sea surface temperature (SST) nudging scheme. The observed positive and negative peaks during late 1990s and late 2000s are well reproduced in the reforecast experiments initiated from 1994 and 1999, respectively. The experiments initiated from 1994 successfully capture warm SST and high sea level pressure anomalies propagating from the South Atlantic to the southern Indian Ocean. Also, the other experiments initiated from 1999 skillfully predict phase change from a positive to negative peak. These results suggest that the SST-nudging initialization has the essence to capture the predictability of the internally generated decadal climate variability in the southern Indian Ocean.

Principles of proportional recovery after stroke generalize to neglect and aphasia.

PubMed

Marchi, N A; Ptak, R; Di Pietro, M; Schnider, A; Guggisberg, A G

2017-08-01

Motor recovery after stroke can be characterized into two different patterns. A majority of patients recover about 70% of initial impairment, whereas some patients with severe initial deficits show little or no improvement. Here, we investigated whether recovery from visuospatial neglect and aphasia is also separated into two different groups and whether similar proportions of recovery can be expected for the two cognitive functions. We assessed 35 patients with neglect and 14 patients with aphasia at 3 weeks and 3 months after stroke using standardized tests. Recovery patterns were classified with hierarchical clustering and the proportion of recovery was estimated from initial impairment using a linear regression analysis. Patients were reliably clustered into two different groups. For patients in the first cluster (n = 40), recovery followed a linear model where improvement was proportional to initial impairment and achieved 71% of maximal possible recovery for both cognitive deficits. Patients in the second cluster (n = 9) exhibited poor recovery (<25% of initial impairment). Our findings indicate that improvement from neglect or aphasia after stroke shows the same dichotomy and proportionality as observed in motor recovery. This is suggestive of common underlying principles of plasticity, which apply to motor and cognitive functions. © 2017 EAN.

Experimental demonstration of a two-phase population extinction hazard

PubMed Central

Drake, John M.; Shapiro, Jeff; Griffen, Blaine D.

2011-01-01

Population extinction is a fundamental biological process with applications to ecology, epidemiology, immunology, conservation biology and genetics. Although a monotonic relationship between initial population size and mean extinction time is predicted by virtually all theoretical models, attempts at empirical demonstration have been equivocal. We suggest that this anomaly is best explained with reference to the transient properties of ensembles of populations. Specifically, we submit that under experimental conditions, many populations escape their initially vulnerable state to reach quasi-stationarity, where effects of initial conditions are erased. Thus, extinction of populations initialized far from quasi-stationarity may be exposed to a two-phase extinction hazard. An empirical prediction of this theory is that the fit Cox proportional hazards regression model for the observed survival time distribution of a group of populations will be shown to violate the proportional hazards assumption early in the experiment, but not at later times. We report results of two experiments with the cladoceran zooplankton Daphnia magna designed to exhibit this phenomenon. In one experiment, habitat size was also varied. Statistical analysis showed that in one of these experiments a transformation occurred so that very early in the experiment there existed a transient phase during which the extinction hazard was primarily owing to the initial population size, and that this was gradually replaced by a more stable quasi-stationary phase. In the second experiment, only habitat size unambiguously displayed an effect. Analysis of data pooled from both experiments suggests that the overall extinction time distribution in this system results from the mixture of extinctions during the initial rapid phase, during which the effects of initial population size can be considerable, and a longer quasi-stationary phase, during which only habitat size has an effect. These are the first results, to our knowledge, of a two-phase population extinction process. PMID:21429907

75 FR 3237 - Proposed Collection; Comment Request; Women's Health Initiative Observational Study

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-20

... DEPARTMENT OF HEALTH AND HUMAN SERVICES National Institutes of Health Proposed Collection; Comment Request; Women's Health Initiative Observational Study SUMMARY: In compliance with the requirement of... Initiative (WHI) Observational Study. Type of Information Collection Request: Revision OMB 0925- 0414. Need...

Age at First Use and Later Substance Use Disorder: Shared Genetic and Environmental Pathways for Nicotine, Alcohol, and Cannabis

PubMed Central

Richmond-Rakerd, Leah S.; Slutske, Wendy S.; Lynskey, Michael T.; Agrawal, Arpana; Madden, Pamela A.F.; Bucholz, Kathleen K.; Heath, Andrew C.; Statham, Dixie J.; Martin, Nicholas G.

2016-01-01

Behavioral genetic studies have provided insights into why early substance use initiation is associated with increased risk for disorder. Few genetically-informative studies, however, have operationalized initiation as the timing of first use and simultaneously modeled the timing of initiation and problematic use of multiple substances. Such research can help capture the risk associated with early initiation and determine the extent to which genetic and environmental risk generalizes across substances. This study utilized a behavior genetic approach to examine the relation between the age of substance use initiation and symptoms of substance use disorder. Participants were 7,285 monozygotic and dizygotic twins (40% male, mean age at interview=30.6) from the Australian Twin Registry who reported on their ages of tobacco, alcohol, and cannabis initiation and symptoms of DSM-IV nicotine dependence, alcohol use disorder, and cannabis use disorder. Biometric modeling was conducted to (a) determine the structure of genetic and environmental influences on initiation and disorder and (b) examine their genetic and environmental overlap. The latent structure of initiation differed across men and women. The familial covariance between initiation and disorder was genetic among men and genetic and environmental among women, suggesting that the relation between first substance use and disorder is partly explained by a shared liability. After accounting for familial overlap, significant unique environmental correlations were observed, indicating that the age of initiation of multiple drugs may directly increase risk for substance-related problems. Results support the utility of conceptualizing initiation in terms of age and of adopting a multivariate approach. PMID:27537477

Long-term Conventionally Dosed Vancomycin Therapy In Patients With Orthopaedic Implant-related Infections Seems As Effective And Safe As Long-term Penicillin Or Clindamycin Therapy. A Retrospective Cohort Study Of 103 Patients.

PubMed

Aleman, Jacomien; Moojen, Dirk Jan F; van Ogtrop, Marc L; Poolman, Rudolf W; Franssen, Eric J F

2018-01-01

Objectives : Antimicrobial therapy is one of the cornerstones of orthopaedic implant-related infections (OIRI) treatment. Infections with Gram-positive bacteria are often treated with vancomycin, penicillin or clindamycin. A recent IDSA guideline suggests increasing the dose of vancomycin to increase the trough vancomycin target serum concentrations. This is deemed necessary because of an observed decrease in vancomycin susceptibility among Gram-positive bacteria. However, elevated vancomycin concentrations are correlated with the risk of nephrotoxicity, especially with prolonged therapy. Compared to most countries, rates of resistance against antibiotics among bacteria in the Netherlands are lower for currently available antibiotics, therefore lower target concentrations of vancomycin are probably efficacious for the treatment of infections. In this study we evaluated the efficacy and safety of long-term conventionally dosed vancomycin therapy, as an initial therapy for OIRI, and compared this with long-term penicillin and clindamycin therapy, as initial therapy, in patients with Gram-positive orthopaedic implant-related infections. Methods : A retrospective, observational study was conducted in 103 adult patients treated for OIRI, with vancomycin, penicillin or clindamycin for at least 10 days. The target trough serum concentration of vancomycin was 10-15 mg/l. Results : 74% of our patients were treated successfully with vancomycin, as initial therapy, (no reinfection within 1 year) versus 55% of our patients treated with either an antibiotic of the penicillin class (mostly flucloxacillin) or clindamycin (p=0.08), as initial therapy. For patients treated with vancomycin we observed a serum creatinine increase of 6 μmol/l, for patients treated with either an antibiotic of the penicillin class or clindamycin the serum creatinine increase was 4 μmol/l (p=0.395). Conclusions : In our population of patients with OIRI long-term treatment with conventionally dosed vancomycin, as initial therapy, was not significantly less effective and safe as long-term treatment with an antibiotic of the penicillin class or clindamycin, as initial therapy.

Long-term Conventionally Dosed Vancomycin Therapy In Patients With Orthopaedic Implant-related Infections Seems As Effective And Safe As Long-term Penicillin Or Clindamycin Therapy. A Retrospective Cohort Study Of 103 Patients

PubMed Central

Aleman, Jacomien; Moojen, Dirk Jan F.; van Ogtrop, Marc L.; Poolman, Rudolf W.; Franssen, Eric J.F.

2018-01-01

Objectives: Antimicrobial therapy is one of the cornerstones of orthopaedic implant-related infections (OIRI) treatment. Infections with Gram-positive bacteria are often treated with vancomycin, penicillin or clindamycin. A recent IDSA guideline suggests increasing the dose of vancomycin to increase the trough vancomycin target serum concentrations. This is deemed necessary because of an observed decrease in vancomycin susceptibility among Gram-positive bacteria. However, elevated vancomycin concentrations are correlated with the risk of nephrotoxicity, especially with prolonged therapy. Compared to most countries, rates of resistance against antibiotics among bacteria in the Netherlands are lower for currently available antibiotics, therefore lower target concentrations of vancomycin are probably efficacious for the treatment of infections. In this study we evaluated the efficacy and safety of long-term conventionally dosed vancomycin therapy, as an initial therapy for OIRI, and compared this with long-term penicillin and clindamycin therapy, as initial therapy, in patients with Gram-positive orthopaedic implant-related infections. Methods: A retrospective, observational study was conducted in 103 adult patients treated for OIRI, with vancomycin, penicillin or clindamycin for at least 10 days. The target trough serum concentration of vancomycin was 10-15 mg/l. Results: 74% of our patients were treated successfully with vancomycin, as initial therapy, (no reinfection within 1 year) versus 55% of our patients treated with either an antibiotic of the penicillin class (mostly flucloxacillin) or clindamycin (p=0.08), as initial therapy. For patients treated with vancomycin we observed a serum creatinine increase of 6 μmol/l, for patients treated with either an antibiotic of the penicillin class or clindamycin the serum creatinine increase was 4 μmol/l (p=0.395). Conclusions: In our population of patients with OIRI long-term treatment with conventionally dosed vancomycin, as initial therapy, was not significantly less effective and safe as long-term treatment with an antibiotic of the penicillin class or clindamycin, as initial therapy. PMID:29761071

Development of a numerical system to improve particulate matter forecasts in South Korea using geostationary satellite-retrieved aerosol optical data over Northeast Asia

NASA Astrophysics Data System (ADS)

Lee, Sojin; Song, Chul-han; Park, Rae Seol; Park, Mi Eun; Han, Kyung man; Kim, Jhoon; Choi, Myungje; Ghim, Young Sung; Woo, Jung-Hun

2016-04-01

To improve short-term particulate matter (PM) forecasts in South Korea, the initial distribution of PM composition, particularly over the upwind regions, is primarily important. To prepare the initial PM composition, the aerosol optical depth (AOD) data retrieved from a geostationary equatorial orbit (GEO) satellite sensor, GOCI (Geostationary Ocean Color Imager) which covers a part of Northeast Asia (113-146° E; 25-47° N), were used. Although GOCI can provide a higher number of AOD data in a semicontinuous manner than low Earth orbit (LEO) satellite sensors, it still has a serious limitation in that the AOD data are not available at cloud pixels and over high-reflectance areas, such as desert and snow-covered regions. To overcome this limitation, a spatiotemporal-kriging (STK) method was used to better prepare the initial AOD distributions that were converted into the PM composition over Northeast Asia. One of the largest advantages in using the STK method in this study is that more observed AOD data can be used to prepare the best initial AOD fields compared with other methods that use single frame of observation data around the time of initialization. It is demonstrated in this study that the short-term PM forecast system developed with the application of the STK method can greatly improve PM10 predictions in the Seoul metropolitan area (SMA) when evaluated with ground-based observations. For example, errors and biases of PM10 predictions decreased by ˜ 60 and ˜ 70{%}, respectively, during the first 6 h of short-term PM forecasting, compared with those without the initial PM composition. In addition, the influences of several factors on the performances of the short-term PM forecast were explored in this study. The influences of the choices of the control variables on the PM chemical composition were also investigated with the composition data measured via PILS-IC (particle-into-liquid sampler coupled with ion chromatography) and low air-volume sample instruments at a site near Seoul. To improve the overall performances of the short-term PM forecast system, several future research directions were also discussed and suggested.

Photoionization of hydrogen in a strong static electric field

NASA Astrophysics Data System (ADS)

Ohgoda, Shun; Tolstikhin, Oleg I.; Morishita, Toru

2017-04-01

We analyze photoionization of hydrogen in the presence of a strong static electric field F ˜0.1 a.u. Such a field essentially modifies the spectrum of the unperturbed atom. Even the ground n =1 state acquires a non-negligible width, while the higher field-free bound states become overlapping resonances. At the same time, static-field-induced states (SFISs) found recently [A. V. Gets and O. I. Tolstikhin, Phys. Rev. A 87, 013419 (2013), 10.1103/PhysRevA.87.013419] emerge in the field-free continuum. We formulate the theory of photoionization from a decaying initial state and define appropriate observables—the reduced photoionization rate and transverse momentum distribution of photoelectrons. These observables are calculated for the four initial states with n =1 and 2 in the different polarization cases. The SFISs are shown to manifest themselves as distinct peaks in the observables. Remarkably, even broad SFISs can be seen as narrow well-pronounced peaks at fields where their widths are comparable to that of the initial state. Such a resonance enhancement of the manifestations of SFISs is the main finding of this paper. This finding suggests that SFISs should manifest themselves also in photoelectron momentum distributions produced by photoionization in the presence of a quasistatic field of intense low-frequency laser pulses currently used in strong-field physics.

Role of Replication and CpG Methylation in Fragile X Syndrome CGG Deletions in Primate Cells

PubMed Central

Nichol Edamura, Kerrie; Leonard, Michelle R.; Pearson, Christopher E.

2005-01-01

Instability of the fragile X CGG repeat involves both maternally derived expansions and deletions in the gametes of full-mutation males. It has also been suggested that the absence of aberrant CpG methylation may enhance repeat deletions through an unknown process. The effect of CGG tract length, DNA replication direction, location of replication initiation, and CpG methylation upon CGG stability were investigated using an SV40 primate replication system. Replication-dependant deletions with 53 CGG repeats were observed when replication was initiated proximal to the repeat, with CGG as the lagging-strand template. When we initiated replication further from the repeat, while maintaining CGG as the lagging-strand template or using CCG as the lagging-strand template, significant instability was not observed. CpG methylation of the unstable template stabilized the repeat, decreasing both the frequency and the magnitude of deletion events. Furthermore, CpG methylation slowed the efficiency of replication for all templates. Interestingly, replication forks displayed no evidence of a block at the CGG repeat tract, regardless of replication direction or CpG methylation status. Templates with 20 CGG repeats were stable under all circumstances. These results reveal that CGG deletions occur during replication and are sensitive to replication-fork dynamics, tract length, and CpG methylation. PMID:15625623

Ultrafast shock compression of an oxygen-balanced mixture of nitromethane and hydrogen peroxide.

PubMed

Armstrong, Michael R; Zaug, Joseph M; Grant, Christian D; Crowhurst, Jonathan C; Bastea, Sorin

2014-08-14

We apply ultrafast optical interferometry to measure the Hugoniot of an oxygen-balanced mixture of nitromethane and hydrogen peroxide (NM/HP) and compare with Hugoniot data for pure nitromethane (NM) and a 90% hydrogen peroxide/water mixture (HP), as well as theoretical predictions. We observe a 2.1% percent mean pairwise difference between the measured shockwave speed (at the measured piston speed) in unreacted NM/HP and the corresponding "universal" liquid Hugoniot, which is larger than the average standard deviation of our data, 1.4%. Unlike the Hugoniots of both HP and NM, in which measured shock speeds deviate to values greater than the unreacted Hugoniot for piston speeds larger than the respective reaction thresholds, in the NM/HP mixture we observe shock speed deviations to values lower than the unreacted Hugoniot well below the von Neumann pressure (≈28 GPa). Although the trend should reverse for high enough piston speeds, the initial behavior is unexpected. Possible explanations range from mixing effects to a complex index of refraction in the reacted solution. If this is indeed a signature of chemical initiation, it would suggest that the process may not be kinetically limited (on a ~100 ps time scale) between the initiation threshold and the von Neumann pressure.

Initiation of Coronal Mass Ejections by Tether-Cutting Reconnection

NASA Technical Reports Server (NTRS)

Moore, Ronald L.; Sterling, Alphonse C.; Falconer, David A.; Six, N. Frank (Technical Monitor)

2002-01-01

We present and interpret examples of the eruptive motion and flare brightening observed in the onset of magnetic explosions that produce coronal mass ejections. The observations are photospheric magnetograms and sequences of coronal and/or chromospheric images. In our examples, the explosion is apparently driven by the ejective eruption of a sigmoidal sheared-field flux rope from the core of an initially closed bipole. This eruption is initiated (triggered and unleashed) by reconnection located either (1) internally, low in the sheared core field, or (2) externally, at a magnetic null above the closed bipole. The internal reconnection is commonly called 'tether-cutting" reconnection, and the external reconnection is commonly called "break-out' reconnection. We point out that break-out reconnection amounts to external tether cutting. In one example, the eruptive motion of the sheared core field starts several minutes prior to any detectable brightening in the coronal images. We suggest that in this case the eruption is triggered by internal tether-cutting reconnection that at first is too slow and/or too localized to produce detectable heating in the coronal images. This work is supported by NASA's Office of Space Science through its Solar & Heliospheric Physics Supporting Research & Technology program and its Sun-Earth Connection Guest Investigator program.

Empirical evaluation of inhibitory product, substrate, and enzyme effects during the enzymatic saccharification of lignocellulosic biomass.

PubMed

Smith, Benjamin T; Knutsen, Jeffrey S; Davis, Robert H

2010-05-01

The cellulose hydrolysis kinetics during batch enzymatic saccharification are typified by a rapid initial rate that subsequently decays, resulting in incomplete conversion. Previous studies suggest that changes associated with the solution, substrate, or enzymes may be responsible. In this work, kinetic experiments were conducted to determine the relative magnitude of these effects. Pretreated corn stover (PCS) was used as a lignocellulosic substrate likely to be found in a commercial saccharification process, while Avicel and Kraft lignin were used to create model substrates. Glucose inhibition was observed by spiking the reaction slurry with glucose during initial-rate experiments. Increasing the glucose concentration from 7 to 48 g/L reduced the cellulose conversion rate by 94%. When product sugars were removed using ultrafiltration with a 10 kDa membrane, the glucose-based conversion increased by 9.5%. Reductions in substrate reactivity with conversion were compared directly by saccharifying PCS and Avicel substrates that had been pre-reacted to different conversions. Reaction of substrate with a pre-conversion of 40% resulted in about 40% reduction in the initial rate of saccharification, relative to fresh substrate with identical cellulose concentration. Overall, glucose inhibition and reduced substrate reactivity appear to be dominant factors, whereas minimal reductions of enzyme activity were observed.

Relativistic initial conditions for N-body simulations

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

Fidler, Christian; Tram, Thomas; Crittenden, Robert

2017-06-01

Initial conditions for (Newtonian) cosmological N-body simulations are usually set by re-scaling the present-day power spectrum obtained from linear (relativistic) Boltzmann codes to the desired initial redshift of the simulation. This back-scaling method can account for the effect of inhomogeneous residual thermal radiation at early times, which is absent in the Newtonian simulations. We analyse this procedure from a fully relativistic perspective, employing the recently-proposed Newtonian motion gauge framework. We find that N-body simulations for ΛCDM cosmology starting from back-scaled initial conditions can be self-consistently embedded in a relativistic space-time with first-order metric potentials calculated using a linear Boltzmann code.more » This space-time coincides with a simple ''N-body gauge'' for z < 50 for all observable modes. Care must be taken, however, when simulating non-standard cosmologies. As an example, we analyse the back-scaling method in a cosmology with decaying dark matter, and show that metric perturbations become large at early times in the back-scaling approach, indicating a breakdown of the perturbative description. We suggest a suitable ''forwards approach' for such cases.« less

Dynamic void behavior in polymerizing polymethyl methacrylate cement.

PubMed

Muller, Scott D; McCaskie, Andrew W

2006-02-01

Cement mantle voids remain controversial with respect to survival of total hip arthroplasty. Void evolution is poorly understood, and attempts at void manipulation can only be empirical. We induced voids in a cement model simulating the constraints of the proximal femur. Intravoid pressure and temperature were recorded throughout polymerization, and the initial and final void volumes were measured. Temperature-dependent peak intravoid pressures and void volume increases were observed. After solidification, subatmospheric intravoid pressures were observed. The magnitude of these observations could not be explained by the ideal gas law. Partial pressures of the void gas at peak pressures demonstrated a dominant effect of gaseous monomer, thereby suggesting that void growth is a pressure-driven phenomenon resulting from temperature-dependent evaporation of monomer into existing trapped air voids.

Experimental observations and finite element analysis of the initiation of fiber microbuckling in notched composite laminates

NASA Technical Reports Server (NTRS)

Guynn, E. Gail; Bradley, Walter L.

1989-01-01

An understanding was developed of the factors that determine the semi-circular edge-notched compressive strength and the associated failure mode(s) were identified of thermoplastic composite laminates with multidirectional stacking sequences. The experimental observations and the detailed literature review suggest at least four factors that affected the determination of the strain levels at which fiber microbuckling initiates and thus, partially control the composite's compression strength. The dependent variables studied are the compressive strength of a reduced gage section compression specimen and the compression strength of a compression specimen with two semi-circular edge notches (no opposite free edges) centered along the gage section. In this research, specimens containing two semi-circular edge notches (no opposite free edges) were loaded in compression at a relatively slow rate to provide more stable development of fiber microbuckling damage. The results indicate that the local constraints (free surfaces, supporting ply orientation, and resin-rich regions) significantly affect the strain level for the initiation of in-plane fiber microbuckling. Preliminary results at an elevated temperature, 77 C, showed the shear stress yield strength of the resin was reduced and consequently, the resistance to fiber microbuckling was also reduced. The finite element analysis of the perfectly straight fiber problem indicates that the free surface effect causes a 10 percent reduction in the critical buckling strain. However, the experimentally measured reduction for fibers with an initial fiber curvature, was 35 percent.

MA transmutation performance in the optimized MYRRHA

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

Malambu, E.; Van den Eynde, G.; Fernandez, R.

MYRRHA (multi-purpose hybrid research reactor for high-tech applications) is a multipurpose research facility currently being developed at SCK-CEN. It will be able to work in both critical and subcritical modes and, cooled by lead-bismuth eutectic. In this paper the minor actinides (MA) transmutation capabilities of MYRRHA are investigated. (Pu + Am, U) MOX fuel and (Np + Am + Cm, Pu) Inert Matrix Fuel test samples have been loaded in the central channel of the MYRRHA critical core and have been irradiated during five cycles, each one consisting of 90 days of operation at 100 MWth and 30 days ofmore » shutdown. The reactivity worth of the test fuel assembly was about 1.1 dollar. A wide range of burn-up level has been achieved, extending from 42 to 110 MWd/kg HM, the samples with lower MA-to-Pu ratios reaching the highest burn-up. This study has highlighted the importance of the initial MA content, expressed in terms of MA/Pu ratio, on the transmutation rate of MA elements. For (Pu + Am, U) MOX fuel samples, a net build-up of MA is observed when the initial content of MA is very low (here, 1.77 wt% MA/Pu) while a net decrease in MA is observed in the sample with an initial content of 5 wt%. This suggests the existence of some 'equilibrium' initial MA content value beyond which a net transmutation is achievable.« less

Saccade-related activity in the prefrontal cortex: its role in eye movement control and cognitive functions

PubMed Central

Funahashi, Shintaro

2014-01-01

Prefrontal neurons exhibit saccade-related activity and pre-saccadic memory-related activity often encodes the directions of forthcoming eye movements, in line with demonstrated prefrontal contribution to flexible control of voluntary eye movements. However, many prefrontal neurons exhibit post-saccadic activity that is initiated well after the initiation of eye movement. Although post-saccadic activity has been observed in the frontal eye field, this activity is thought to be a corollary discharge from oculomotor centers, because this activity shows no directional tuning and is observed whenever the monkeys perform eye movements regardless of goal-directed or not. However, prefrontal post-saccadic activities exhibit directional tunings similar as pre-saccadic activities and show context dependency, such that post-saccadic activity is observed only when monkeys perform goal-directed saccades. Context-dependency of prefrontal post-saccadic activity suggests that this activity is not a result of corollary signals from oculomotor centers, but contributes to other functions of the prefrontal cortex. One function might be the termination of memory-related activity after a behavioral response is done. This is supported by the observation that the termination of memory-related activity coincides with the initiation of post-saccadic activity in population analyses of prefrontal activities. The termination of memory-related activity at the end of the trial ensures that the subjects can prepare to receive new and updated information. Another function might be the monitoring of behavioral performance, since the termination of memory-related activity by post-saccadic activity could be associated with informing the correctness of the response and the termination of the trial. However, further studies are needed to examine the characteristics of saccade-related activities in the prefrontal cortex and their functions in eye movement control and a variety of cognitive functions. PMID:25071482

An Mcm10 Mutant Defective in ssDNA Binding Shows Defects in DNA Replication Initiation.

PubMed

Perez-Arnaiz, Patricia; Kaplan, Daniel L

2016-11-20

Mcm10 is an essential protein that functions to initiate DNA replication after the formation of the replication fork helicase. In this manuscript, we identified a budding yeast Mcm10 mutant (Mcm10-m2,3,4) that is defective in DNA binding in vitro. Moreover, this Mcm10-m2,3,4 mutant does not stimulate the phosphorylation of Mcm2 by Dbf4-dependent kinase (DDK) in vitro. When we expressed wild-type levels of mcm10-m2,3,4 in budding yeast cells, we observed a severe growth defect and a substantially decreased DNA replication. We also observed a substantially reduced replication protein A- chromatin immunoprecipitation signal at origins of replication, reduced levels of DDK-phosphorylated Mcm2, and diminished Go, Ichi, Ni, and San (GINS) association with Mcm2-7 in vivo. mcm5-bob1 bypasses the growth defect conferred by DDK-phosphodead Mcm2 in budding yeast. However, the growth defect observed by expressing mcm10-m2,3,4 is not bypassed by the mcm5-bob1 mutation. Furthermore, origin melting and GINS association with Mcm2-7 are substantially decreased for cells expressing mcm10-m2,3,4 in the mcm5-bob1 background. Thus, the origin melting and GINS-Mcm2-7 interaction defects we observed for mcm10-m2,3,4 are not explained by decreased Mcm2 phosphorylation by DDK, since the defects persist in an mcm5-bob1 background. These data suggest that DNA binding by Mcm10 is essential for the initiation of DNA replication. Copyright © 2016 Elsevier Ltd. All rights reserved.

Evidence of a dominance hierarchy in captive Caribbean flamingos and its relation to pair bonding and physiological measures of health.

PubMed

Royer, Erica A; Anderson, Matthew J

2014-06-01

Caribbean flamingo social structure, how pair bonds affect the structure of the flock, and how social stress affects health measured by heterophil to lymphocyte ratios (H/L) were investigated at the Philadelphia Zoo. It was hypothesized that a hierarchy may become apparent by analyzing agonistic interactions and that paired individuals would share similar places within the hierarchy. Furthermore, it was hypothesized that a negative relationship between H/L ratio and dominance would exist. Forty observations were conducted and in 70% of interactions instigating bird(s) won the encounter, suggesting either some advantage for instigating birds or a prior expectation of an encounter's outcome based upon an understanding of the flock's hierarchy. The flock possessed a semi-linear hierarchy (in terms of wins/losses) and birds with higher pair-bond strengths maintained dominant positions, suggesting that pair-bonding may help individuals become more successful in agonistic encounters. Birds who won more often had higher lymphocytes percentages and analyses suggested a trend indicating dominant birds may be less stressed. A semi-linear hierarchy was also found in terms of initiation/being targeted, and a bird's rank on the dominance (wins/losses) and initiate/target hierarchies were positively correlated, suggesting that subdominant birds were targeted by dominant birds more frequently than vice versa. Copyright © 2014 Elsevier B.V. All rights reserved.

Sequence of slow slip events and low frequency earthquakes in the shallow part of the Nankai Trough seismogenic zone observed by seafloor observation network.

NASA Astrophysics Data System (ADS)

Araki, E.; Saffer, D. M.; Kopf, A.; To, A.; Ide, S.; Nakano, M.; Kimura, T.; Machida, Y.

2016-12-01

Seismic behavior of the thrust zone in trench side of the seismically coupled plate interface in the Nankai Trough is poorly understood because shore based seismic and geodetic observation does not have enough sensitivity to detect slow activity in the area. In these years, we constructed dense seafloor observation network in combination with pore-fluid pressure, strain, and seismic sensing in IODP deep boreholes (C0002G and C0010A) and 20+ seafloor broadband seismometers cabled to the observation network called DONET for long-term continuous observation in the To-Nankai area of the Nankai Trough, south of Japan. Analysis of the seismic records from DONET seafloor seismometer and pore-fluid pressure records from the boreholes in the period from Jan. 2011 to Apr. 2016 revealed the activities of the slow slip events (SSE), low frequency tremor (LFT), and very low frequency earthquakes (VLFE) in the observation network, detecting seven sequence of pore-fluid pressure transients in these boreholes representing SSEs and many LFT and VLFEs from seismic records. Some of the SSE sequence accompanies active LFT swarms in the regions offshore of the locked seismogenic zone. Some of the pressure transient initiate precedent to the LFT swarms, as well as some does not accompany obvious LFT activity, as if the SSE occurs "silently", suggesting LFT does not express SSE but LFT seems activated by the SSE. This is also supported by change of SSE pressure transient rate in accordance with LFT activity, observed in sequences in Mar. 2011, Oct. 2015, and April 2016. In the Oct. 2015 sequence, observed pressure transient in two boreholes indicates the slip propagates updip in the shallow subduction zone. In many sequences including this sequence, we ientify that the LFT swarm tends to migrate updip direction. The pressure transient in Apr. 2016 also followed this tendency, initiating from co-seismic compression by Apr. 1 earthquake occurred downdip side of the boreholes, followed by further compression due to the after slip, and slow release of the pressure suggesting SSE along with very active LFT and VLFE activities migrating offshore direction in the following two weeks period. The SSE seemed further activated by teleseismic events Kumamoto earthquake in Apr. 17.

Mood changes following social dance sessions in people with Parkinson's disease.

PubMed

Lewis, Carine; Annett, Lucy E; Davenport, Sally; Hall, Amelia A; Lovatt, Peter

2016-04-01

Dance interventions have physical benefits for the elderly, especially those with Parkinson's disease. This study assessed the psychological benefits of dance. A total of 37 participants, with either Parkinson's disease (n= 22) or age-matched controls (n= 15) completed mood questionnaires before and after a 10-week dance intervention. An overall reduction in total mood disturbance and a specific reduction in anger were observed. In addition, less fatigue was found for those initially scoring higher in depression. This suggests that dance can provide psychological benefits for both people with Parkinson's disease and the elderly, with findings suggesting that this is an avenue to be explored further. © The Author(s) 2014.

The nature, origin and evolution of embedded star clusters

NASA Technical Reports Server (NTRS)

Lada, Charles J.; Lada, Elizabeth A.

1991-01-01

The recent development of imaging infrared array cameras has enabled the first systematic studies of embedded protoclusters in the galaxy. Initial investigations suggest that rich embedded clusters are quite numerous and that a significant fraction of all stars formed in the galaxy may begin their lives in such stellar systems. These clusters contain extremely young stellar objects and are important laboratories for star formation research. However, observational and theoretical considerations suggest that most embedded clusters do not survive emergence from molecular clouds as bound clusters. Understanding the origin, nature, and evolution of embedded clusters requires understanding the intimate physical relation between embedded clusters and the dense molecular cloud cores from which they form.

OSO-8 observations of the impulsive phase of solar flares in the transition-zone and corona

NASA Technical Reports Server (NTRS)

Lites, B. W.; Bruner, E. C., Jr.; Wolfson, C. J.

1981-01-01

Several solar flares were observed from their onset in C IV 1548.2 A and 1-8 A X-rays using instruments on OSO-8. It is found that impulsive brightening in C IV is often accompanied by redshifts, interpreted as downflows, of the order of 80 km/s. The maximum soft X-ray intensity usually arrives several minutes after the maximum C IV intensity. The most energetic C IV event observed shows a small blueshift just before reaching maximum intensity; estimates of the mass flux associated with this upflow through the transition zone are consistent with the increase of mass in the coronal loops as observed in soft X-rays. Finally, it is suggested that the frequent occurrence of violent dynamical processes at the onset of the flare is associated with the initial energy release mechanism.

Lithium in halo stars - Constraining the effects of helium diffusion on globular cluster ages and cosmology

NASA Technical Reports Server (NTRS)

Deliyannis, Constantine P.; Demarque, Pierre

1991-01-01

Stellar evolutionary models with diffusion are used to show that observations of lithium in extreme halo stars provide crucial constraints on the magnitude of the effects of helium diffusion. The flatness of the observed Li-T(eff) relation severely constrains diffusion Li isochrones, which tend to curve downward toward higher T(eff). It is argued that Li observations at the hot edge of the plateau are particularly important in constraining the effects of helium diffusion; yet, they are currently few in number. It is proposed that additional observations are required there, as well as below 5500 K, to define more securely the morphology of the halo Li abundances. Implications for the primordial Li abundance are considered. It is suggested that a conservative upper limit to the initial Li abundance, due to diffusive effects alone, is 2.35.

Diffraction-based study of fatigue crack initiation and propagation in aerospace aluminum alloys

NASA Astrophysics Data System (ADS)

Gupta, Vipul K.

The crack initiation sites and microstructure-sensitive growth of small fatigue cracks are experimentally characterized in two precipitation-hardened aluminum alloys, 7075-T651 and 7050-T7451, stressed in ambient temperature moist-air (warm-humid) and -50°C dry N2 (cold-dry) environmental conditions. Backscattered electron imaging (BSE) and energy dispersive spectroscopy (EDS) of the fracture surfaces showed that Fe-Cu rich constituent particle clusters are the most common initiation sites within both alloys stressed in either environment. The crack growth within each alloy, on average, was observed to be slowed in the cold-dry environment than in the warm-humid environment, but only at longer crack lengths. Although no overwhelming effects of grain boundaries and grain orientations on small-crack growth were observed, crack growth data showed local fluctuations within individual grains. These observations are understood as crack propagation through the underlying substructure at the crack surface and frequent interaction with low/high-angle grain and subgrain boundaries, during cyclic loading, and, are further attributed to periodic changes in crack propagation path and multiple occurrences of crack-branching observed in the current study. SEM-based stereology in combination with electron backscattered diffraction (EBSD) established fatigue crack surface crystallography within the region from ˜1 to 50 mum of crack initiating particle clusters. Fatigue crack facets were parallel to a wide variety of crystallographic planes, with pole orientations distributed broadly across the irreducible stereographic triangle between the {001} and {101}-poles within both warm-humid and cold-dry environments. The results indicate environmentally affected fatigue cracking in both cases, given the similarity between the observed morphology and crystallography with that of a variety of aerospace aluminum alloys cracked in the presence of moist-air. There was no evidence of crystallographic {111} slip-plane cracking typical of the Stage I crack growth mode observed in single crystals and high purity polycrystals of face centered cubic metals, and which has presently been assumed for the present materials within fatigue crack initiation models. Rather, the facets tend to have near-Mode I spatial orientation, which is another indicator of the importance of environmentally affected fatigue damage. The results provide a physical basis to develop microstructurally-based next generation multi-stage fatigue (MSF) models that should include a new crack decohesion criteria based upon environmental fatigue cracking mechanisms. EBSD study of small-cracks in alloy 7050-T7451, stressed in warm-humid environment, showed that crack-path orientation changes and crack-branching occurred at both low/high-angle grain and subgrain boundaries. Single surface trace analysis suggests that the crack-path differs substantially from crystallographic slip-planes. EBSD-based observations of small-crack propagation through subgrain structure, either formed by cyclic plastic strain accumulation or pre-existing (typical of unrecrystallized grain structure in the present materials), suggest that subgrain structure plays a crucial role in small fatigue crack propagation. As mentioned earlier, local fluctuations in small-crack growth rates appear to be caused by frequent interaction with subgrain boundaries, and multiple occurrences of crack-branching and crack-path orientation changes at low/high-angle grain and subgrain boundaries. The aforementioned deviation from low-index {001}/{101}-planes and the occurrence of high-index cracking planes observed by EBSD/Stereology, in this study and others, are interpreted as trans-subgranular decohesion or inter-subgranular cracking, due to trapped hydrogen. In summary, the results provide a firmer experimental foundation for, and clearer understanding of, the mechanisms of environmental fatigue cracking of aluminum alloys, especially the role of inter-subgranular cracking, which had previously been advanced based upon fracture surface observations alone.

Dependence of transition temperature on hole concentration per CuO2 sheet in the Bi-based superconductors

NASA Technical Reports Server (NTRS)

Zhao, J.; Seehra, M. S.

1991-01-01

The recently observed variations of the transition temperature (T sub c) with oxygen content in the Bi based (2212) and (2223) superconductors are analyzed in terms of p+, the hole concentration per CuO2 sheet. This analysis shows that in this system, T sub c increases with p+ initially, reaching maxima at p+ = 0.2 approx. 0.3, followed by monotonic decrease of T sub c with p+. The forms of these variations are similar to those observed in the La(2-x)Sr(x)CuO4 and YBa2Cu3Oy systems, suggesting that p+ may be an important variable governing superconductivity in the cuprate superconductors.

Io: Escape and ionization of atmospheric gases

NASA Technical Reports Server (NTRS)

Smyth, W. H.

1981-01-01

Models for the Io oxygen clouds were improved to calculate the two dimensional sky plane intensity of the 1304 A emission and the 880 A emission of atomic oxygen, in addition to the 6300 A emission intensity. These three wavelength emissions are those for which observational measurements have been performed by ground based, rocket, Earth orbiting satellite and Voyager spacecraft instruments. Comparison of model results and observations suggests that an oxygen flux from Io of about 3 billion atoms sq cm sec is required for agreement. Quantitative analysis of the Io sodium cloud has focused upon the initial tasks of acquiring and preliminary evaluation of new sodium cloud and Io plasma torus data.

Shear Shock Waves Observed in the Brain

NASA Astrophysics Data System (ADS)

Espíndola, David; Lee, Stephen; Pinton, Gianmarco

2017-10-01

The internal deformation of the brain is far more complex than the rigid motion of the skull. An ultrasound imaging technique that we have developed has a combination of penetration, frame-rate, and motion-detection accuracy required to directly observe the formation and evolution of shear shock waves in the brain. Experiments at low impacts on the traumatic-brain-injury scale demonstrate that they are spontaneously generated and propagate within the porcine brain. Compared to the initially smooth impact, the acceleration at the shock front is amplified up to a factor of 8.5. This highly localized increase in acceleration suggests that shear shock waves are a previously unappreciated mechanism that could play a significant role in traumatic brain injury.

Results from a limited area mesoscale numerical simulation for 10 April 1979

NASA Technical Reports Server (NTRS)

Kalb, M. W.

1985-01-01

Results are presented from a nine-hour limited area fine mesh (35-km) mesoscale model simulation initialized with SESAME-AVE I radiosonde data for Apr. 10, 1979 at 2100 GMT. Emphasis is on the diagnosis of mesoscale structure in the mass and precipitation fields. Along the Texas/Oklahoma border, independent of the short wave, convective precipitation formed several hours into the simulation and was organized into a narrow band suggestive of the observed April 10 squall line.

The ionization structure of planetary nebulae. IX - NGC 1535

NASA Technical Reports Server (NTRS)

Barker, Timothy

1989-01-01

The ionization structure of planetary nebula NGC 1535 was investigated using spectrophotometric observations of emission-line intensities over the spectral range 1400-7200 A, which were carried out in five positions in this nebula. The results obtained on the ionic abundances of He, O, N, Ne, C, and Ar in NGC 1535 suggest that it is a planetary nebula that formed initially in a somewhat metal-poor region and has undergone little or no enhancement of its original abundances by mixing with nuclear-processed material.

Wide energy electron precipitations associated with chorus waves; Initial observations from Arase and ground-based observations

NASA Astrophysics Data System (ADS)

Miyoshi, Y.; Kurita, S.; Saito, S.; Shinohara, I.; Kasahara, Y.; Matsuda, S.; Kasaba, Y.; Yagitani, S.; Kojima, H.; Hikishima, M.; Tsuchiya, F.; Kumamoto, A.; Katoh, Y.; Matsuoka, A.; Higashio, N.; Mitani, T.; Takashima, T.; Kasahara, S.; Yokota, S.; Asamura, K.; Kazama, Y.; Wang, S. Y.; Shiokawa, K.; Oyama, S. I.; Ogawa, Y.; Hosokawa, K.; Kataoka, R.; Kero, A.; Hori, T.; Turunen, E. S.; Shoji, M.; Teramoto, M.; Chang, T. F.

2017-12-01

The pulsating aurora is caused by intermittent precipitations of a few - 10s keV electrons, and it is expected that the pitch angle scattering by chorus waves at the magnetosphere is a primary process to cause the pulsating aurora. The Arase satellite that was launched in December, 2016 has obtained comprehensive data sets for plasma/particles and fields/waves. In March and April, 2017, a series of campaign observation focused on the chorus-wave particle interactions from conjugate observations from Arase and ground-based observations, and the pulsating aurora as a manifest of chorus-wave particle ineteractions was the important observation subject. During the campaign observations, good conjugate observations were realized between Arase and ground-based observations in Scandinavia. Associated with the pulsating aurora, the EISCAT VHF incoherent scatter radar at Tromso, Norway observed strong ionization in lower ionosphere. During the period, the Arase satellite observed intense chorus waves near the magnetic equator for a few hours, suggesting that strong pitch angle scattering took place. From the conjugate observations from Arase and ground-based observations, we discuss how chorus waves cause strong precipitation of electrons from plasma sheet and radiation belts.

Suggested posthypnotic amnesia in psychiatric patients and normals.

PubMed

Frischholz, Edward J; Lipman, Laurie S; Braun, Bennett G; Sachs, Roberta

2015-01-01

The present study examined both quantitative and qualitative hypnotizability differences among four psychiatric patient groups (dissociative disorder (n = 17), schizophrenic (n = 13), mood disorder (n = 14), and anxiety disorder (n = 14) patients), and normals (college students (n = 63)). Dissociative disorder patients earned significantly higher corrected total scores on the Stanford Hypnotic Susceptibility Scale, Form C (mean = 7.94), than all other groups. Likewise, dissociative disorder patients initially recalled significantly fewer items when the posthypnotic amnesia suggestion was in effect (mean = .41) and reversed significantly more items when the suggestion was canceled (mean = 3.82) than all other groups. In contrast, schizophrenic patients recalled significantly fewer items when the amnesia suggestion was in effect (mean = 1.85) and reversed significantly fewer items when it was canceled (mean = .77) than the remaining groups. This qualitative difference between schizophrenic patients and the other groups on the suggested posthypnotic amnesia item was observed even though there were no significant quantitative differences between groups in overall hypnotic responsivity.

"Blurred lines?" Sexual aggression and barroom culture.

PubMed

Graham, Kathryn; Bernards, Sharon; Wayne Osgood, D; Abbey, Antonia; Parks, Michael; Flynn, Andrea; Dumas, Tara; Wells, Samantha

2014-05-01

Meeting potential sexual/romantic partners for mutual pleasure is one of the main reasons young adults go to bars. However, not all sexual contacts are positive and consensual, and aggression related to sexual advances is a common experience. Sometimes such aggression is related to misperceptions in making and receiving sexual advances while other times aggression reflects intentional harassment or other sexually aggressive acts. This study uses objective observational research to assess quantitatively gender of initiators and targets and the extent that sexual aggression involves intentional aggression by the initiator, the nature of responses by targets, and the role of third parties and intoxication. We analyzed 258 aggressive incidents involving sexual advances observed as part of a larger study on aggression in large capacity bars and clubs, using variables collected as part of the original research (gender, intoxication, intent) and variables coded from narrative descriptions (invasiveness, persistence, targets' responses, role of third parties). Hierarchical linear modeling analyses were used to account for nesting of incidents in evening and bars. Ninety percent of incidents involved male initiators and female targets, with almost all incidents involving intentional or probably intentional aggression. Targets mostly responded nonaggressively, usually using evasion. Staff rarely intervened; patron third parties intervened in 21% of incidents, usually to help the target but sometimes to encourage the initiator. initiators' level of invasiveness was related to intoxication of the targets, but not their own intoxication, suggesting intoxicated women were being targeted. Sexual aggression is a major problem in bars often reflecting intentional sexual invasiveness and unwanted persistence rather than misperceptions in sexual advances. Prevention needs to focus on addressing masculinity norms of male patrons and staff who support sexual aggression and better management of the highly sexualized and sexist environments of most bars. Copyright © 2014 by the Research Society on Alcoholism.

Clinical outcomes of anti-androgen withdrawal and subsequent alternative anti-androgen therapy for advanced prostate cancer following failure of initial maximum androgen blockade

PubMed Central

MOMOZONO, HIROYUKI; MIYAKE, HIDEAKI; TEI, HIROMOTO; HARADA, KEN-ICHI; FUJISAWA, MASATO

2016-01-01

The present study aimed to investigate the significance of anti-androgen withdrawal and/or subsequent alternative anti-androgen therapy in patients with advanced prostate cancer (PC) who relapsed after initial maximum androgen blockade (MAB). The present study evaluated the clinical outcomes of 272 consecutive advanced PC patients undergoing anti-androgen withdrawal and/or subsequent alternative anti-androgen therapy with flutamide following the failure of initial MAB using bicalutamide. With the exception of 41 patients (15.1%) who did not undergo anti-androgen withdrawal due to the characteristics of PC suggesting aggressive diseases, prostate-specific antigen (PSA) declined from the baseline value in 83 patients (35.9%), including 18 (7.8%) with PSA decline >50%, but not in the remaining 148 (64.1%). No significant difference in the overall survival (OS) or cancer-specific survival (CSS) among the three groups was observed based on the response to anti-androgen withdrawal. Following the introduction of alternative anti-androgen therapy with flutamide, PSA decline was observed in 185 patients (68.0%), including 103 (37.9%) who achieved a PSA reduction of >50%; however, the PSA level continued to elevate in the remaining 87 (32.0%). Furthermore, of the numerous factors examined, only the duration of the initial MAB therapy was shown to be significantly correlated with the PSA decline following alternative anti-androgen therapy. Multivariate analysis of several factors identified revealed that only PSA decline following alternative anti-androgen therapy was an independent predictor of CSS and OS. If initial MAB is effective, the introduction of alternative anti-androgen therapy may be considered; however, anti-androgen withdrawal should be omitted, irrespective of the characteristics of advanced PC. PMID:27123292

A Longitudinal Study of Exposure to Retail Cigarette Advertising and Smoking Initiation

PubMed Central

Henriksen, Lisa; Schleicher, Nina C.; Feighery, Ellen C.; Fortmann, Stephen P.

2011-01-01

OBJECTIVES Accumulating evidence suggests that widespread advertising for cigarettes at the point of sale encourages adolescents to smoke; however, no longitudinal study of exposure to retail tobacco advertising and smoking behavior has been reported. METHODS A school-based survey included 1681 adolescents (aged 11–14 years) who had never smoked. One measure of exposure assessed the frequency of visiting types of stores that contain the most cigarette advertising. A more detailed measure combined data about visiting stores near school with observations of cigarette advertisements and pack displays in those stores. Follow-up surveys 12 and 30 months after baseline (retention rate: 81%) documented the transition from never to ever smoking, even just a puff. RESULTS After 12 months, 18% of adolescents initiated smoking, but the incidence was 29% among students who visited convenience, liquor, or small grocery stores at least twice per week and 9% among those who reported the lowest visit frequency (less than twice per month). Adjusting for multiple risk factors, the odds of initiation remained significantly higher (odds ratio: 1.64 [95% confidence interval: 1.06–2.55]) for adolescents who reported moderate visit frequency (0.5–1.9 visits per week), and the odds of initiation more than doubled for those who visited ≥2 times per week (odds ratio: 2.58 [95% confidence interval: 1.68–3.97]). Similar associations were observed for the more detailed exposure measure and persisted at 30 months. CONCLUSIONS Exposure to retail cigarette advertising is a risk factor for smoking initiation. Policies and parenting practices that limit adolescents’ exposure to retail cigarette advertising could improve smoking prevention efforts. PMID:20643725

Assessment of safety and efficacy of lamotrigine over the course of 1-year observation in Japanese patients with bipolar disorder: post-marketing surveillance study report

PubMed Central

Terao, Takeshi; Ishida, Atsuko; Kimura, Toshifumi; Yoshida, Mitsuhiro; Hara, Terufumi

2017-01-01

Background A post-marketing surveillance (PMS) study was conducted with a 1-year observation period to assess the safety and efficacy of lamotrigine in routine clinical practice in patients with bipolar disorder (BD). Patients and methods Central enrollment method was used to recruit patients diagnosed with BD who were being treated for the first time with lamotrigine to prevent the recurrence/relapse of BD mood episodes. Adverse drug reactions (ADRs) and recurrence/relapse were assessed. Improvement of mania and depression was also assessed using the Hamilton’s Rating Scale for Depression (HAM-D) and the Young Mania Rating Scale (YMRS) at treatment initiation, 4–6 months post treatment initiation, and 10–12 months post treatment initiation. Results A total of 237/989 patients (24.0%) reported ADRs, most commonly rash (9.1%), and the incidence of serious ADRs was 3.3% (33/989 patients). Skin disorders occurred in 130 patients (13.1%), mostly within 8 weeks post treatment. A total of 237/703 patients (33.7%) experienced recurrence/relapse of mood episodes. The 25th percentile of the time to recurrence/relapse of mood episodes was 105 days. Remission of depression symptoms (HAM-D ≤7) occurred in 147/697 patients (21.1%) at treatment initiation, rising to 361 patients (67.4%) at 10–12 months post treatment. Remission of manic symptoms (YMRS ≤13) occurred in 615/676 patients (91.0%) at treatment initiation, rising to 500 patients (97.3%) at 10–12 months post treatment. Conclusion The results of this PMS study suggest that lamotrigine is a well-tolerated and effective drug for preventing recurrence/relapse of BD in clinical practice. PMID:28652744

A multi-directional tracer test in the fractured Chalk aquifer of E. Yorkshire, UK.

PubMed

Hartmann, S; Odling, N E; West, L J

2007-12-07

A multi-borehole radial tracer test has been conducted in the confined Chalk aquifer of E. Yorkshire, UK. Three different tracer dyes were injected into three injection boreholes and a central borehole, 25 m from the injection boreholes, was pumped at 330 m(3)/d for 8 days. The breakthrough curves show that initial breakthrough and peak times were fairly similar for all dyes but that recoveries varied markedly from 9 to 57%. The breakthrough curves show a steep rise to a peak and long tail, typical of dual porosity aquifers. The breakthrough curves were simulated using a 1D dual porosity model. Model input parameters were constrained to acceptable ranges determined from estimations of matrix porosity and diffusion coefficient, fracture spacing, initial breakthrough times and bulk transmissivity of the aquifer. The model gave equivalent hydraulic apertures for fractures in the range 363-384 microm, dispersivities of 1 to 5 m and matrix block sizes of 6 to 9 cm. Modelling suggests that matrix block size is the primary controlling parameter for solute transport in the aquifer, particularly for recovery. The observed breakthrough curves suggest results from single injection-borehole tracer tests in the Chalk may give initial breakthrough and peak times reasonably representative of the aquifer but that recovery is highly variable and sensitive to injection and abstraction borehole location. Consideration of aquifer heterogeneity suggests that high recoveries may be indicative of a high flow pathway adjacent, but not necessarily connected, to the injection and abstraction boreholes whereas low recoveries may indicate more distributed flow through many fractures of similar aperture.

High diversity, low disparity and small body size in plesiosaurs (Reptilia, Sauropterygia) from the Triassic-Jurassic boundary.

PubMed

Benson, Roger B J; Evans, Mark; Druckenmiller, Patrick S

2012-01-01

Invasion of the open ocean by tetrapods represents a major evolutionary transition that occurred independently in cetaceans, mosasauroids, chelonioids (sea turtles), ichthyosaurs and plesiosaurs. Plesiosaurian reptiles invaded pelagic ocean environments immediately following the Late Triassic extinctions. This diversification is recorded by three intensively-sampled European fossil faunas, spanning 20 million years (Ma). These provide an unparalleled opportunity to document changes in key macroevolutionary parameters associated with secondary adaptation to pelagic life in tetrapods. A comprehensive assessment focuses on the oldest fauna, from the Blue Lias Formation of Street, and nearby localities, in Somerset, UK (Earliest Jurassic: 200 Ma), identifying three new species representing two small-bodied rhomaleosaurids (Stratesaurus taylori gen et sp. nov.; Avalonnectes arturi gen. et sp. nov) and the most basal plesiosauroid, Eoplesiosaurus antiquior gen. et sp. nov. The initial radiation of plesiosaurs was characterised by high, but short-lived, diversity of an archaic clade, Rhomaleosauridae. Representatives of this initial radiation were replaced by derived, neoplesiosaurian plesiosaurs at small-medium body sizes during a more gradual accumulation of morphological disparity. This gradualistic modality suggests that adaptive radiations within tetrapod subclades are not always characterised by the initially high levels of disparity observed in the Paleozoic origins of major metazoan body plans, or in the origin of tetrapods. High rhomaleosaurid diversity immediately following the Triassic-Jurassic boundary supports the gradual model of Late Triassic extinctions, mostly predating the boundary itself. Increase in both maximum and minimum body length early in plesiosaurian history suggests a driven evolutionary trend. However, Maximum-likelihood models suggest only passive expansion into higher body size categories.

A cumulative shear mechanism for tissue damage initiation in shock-wave lithotripsy.

PubMed

Freund, Jonathan B; Colonius, Tim; Evan, Andrew P

2007-09-01

Evidence suggests that inertial cavitation plays an important role in the renal injury incurred during shock-wave lithotripsy. However, it is unclear how tissue damage is initiated, and significant injury typically occurs only after a sufficient dose of shock waves. Although it has been suggested that shock-induced shearing might initiate injury, estimates indicate that individual shocks do not produce sufficient shear to do so. In this paper, we hypothesize that the cumulative shear of the many shocks is damaging. This mechanism depends on whether there is sufficient time between shocks for tissue to relax to its unstrained state. We investigate the mechanism with a physics-based simulation model, wherein the basement membranes that define the tubules and vessels in the inner medulla are represented as elastic shells surrounded by viscous fluid. Material properties are estimated from in-vitro tests of renal basement membranes and documented mechanical properties of cells and extracellular gels. Estimates for the net shear deformation from a typical lithotripter shock (approximately 0.1%) are found from a separate dynamic shock simulation. The results suggest that the larger interstitial volume (approximately 40%) near the papilla tip gives the tissue there a relaxation time comparable to clinical shock delivery rates (approximately 1 Hz), thus allowing shear to accumulate. Away from the papilla tip, where the interstitial volume is smaller (approximately 20%), the model tissue relaxes completely before the next shock would be delivered. Implications of the model are that slower delivery rates and broader focal zones should both decrease injury, consistent with some recent observations.

Solar Energetic Particle Events and CME Accelerations in the Low Corona: MLSO Observations

NASA Astrophysics Data System (ADS)

St Cyr, O. C.; Kahler, S. W.; Richardson, I. G.; Cane, H. V.; Xie, H.; Burkepile, J.

2016-12-01

The low solar corona (< 2.5 Rs) is the region in which maximum coronal mass ejection (CME) acceleration occurs and where Type II radio observations suggest that shock formation occurs (Mäkelä et al., 2015). It is therefore a key region for investigations of solar energetic particle (SEP) acceleration by CME-driven shocks. Observations very low in the corona are necessary to detect the rapid CME accelerations leading to shock formation and to assess the speeds of CMEs through the middle corona. However, these observations cannot be made by space borne coronagraphs in which CME trajectories above the occulting disk are usually characterized by a single (constant) speed: e.g., 80% of the speeds in the compilation of SMM CMEs (Burkepile and St. Cyr, 1993) and SOHO LASCO CMEs (St. Cyr et al., 2000). The Mk3/Mk4/K-Cor coronameters at the Mauna Loa Solar Observatory are able to measure the initial accelerations of CMEs low in the corona (i.e., < 2 Rs). We examine a subset of CMEs that were associated with SEP events between 1980-present. The subset is based on the CME launch occurring between 16 UT - 01 UT - the MLSO observing window. In most cases, the CME accelerations are significantly larger than those measured by spaceborne coronagraphs (e.g., SMM, Solwind, LASCO, SECCHI). We will present the preliminary results of a comparison of the SEP parameters with initial CME accelerations in the MLSO coronagraph field of view.

ELUCID—Exploring the Local Universe with the reConstructed Initial Density Field. II. Reconstruction Diagnostics, Applied to Numerical Halo Catalogs

NASA Astrophysics Data System (ADS)

Tweed, Dylan; Yang, Xiaohu; Wang, Huiyuan; Cui, Weiguang; Zhang, Youcai; Li, Shijie; Jing, Y. P.; Mo, H. J.

2017-05-01

The ELUCID project aims to build a series of realistic cosmological simulations that reproduce the spatial and mass distributions of the galaxies as observed in the Sloan Digital Sky Survey. This requires powerful reconstruction techniques to create constrained initial conditions (ICs). We test the reconstruction method by applying it to several N-body simulations. We use two medium-resolution simulations, which each produced three additional constrained N-body simulations. We compare the resulting friend-of-friend catalogs by using the particle indexes as tracers, and quantify the quality of the reconstruction by varying the main smoothing parameter. The cross-identification method we use proves to be efficient, and the results suggest that the most massive reconstructed halos are effectively traced from the same Lagrangian regions in the ICs. A preliminary time-dependence analysis indicates that high-mass-end halos converge only at a redshift close to the reconstruction redshift. This suggests that, for earlier snapshots, only collections of progenitors may be effectively cross-identified.

Changes in inositol phosphates in wild carrot cells upon initiation of cell wall digestion

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

Rincon, M.; Boss, W.F.

1987-04-01

Previous studies have shown that inositol trisphosphate (IP/sub 3/) stimulated /sup 45/Ca/sup +2/ efflux from fusogenic carrot protoplasts and it was suggested that IP/sub 3/ may serve as a second messenger for the mobilization of intracellular Ca/sup +2/ in higher plant cells. To determine whether or not inositol phosphate metabolism changes in response to external stimuli, the cells were labeled with myo-(2-/sup 3/H) inositol for 18 h and exposed to cell wall digestion enzymes, Driselase. The inositol phosphates were extracted with ice cold 10% TCA and separated by anion exchange chromatography. The radioactivity of the fraction that contained IP/sub 3/more » increased 2-3.8 fold and that which contained inositol bisphosphate increased 1.9-2.6 fold within 1.5 min of exposure to Driselase. After 6 min, the radioactivity of both fractions increased 6-7.7 fold and an increase in inositol monophosphate was observed. These data indicate that inositol phosphate metabolism is stimulated by Driselase and suggest polyphosphoinositide hydrolysis occurs upon initiation of cell wall digestion.« less

Information Rx: Prescribing Good Consumerism and Responsible Citizenship

PubMed Central

de Bont, Antoinette

2007-01-01

Recent medical informatics and sociological literature has painted the image of a new type of patient—one that is reflexive and informed, with highly specified information needs and perceptions, as well as highly developed skills and tactics for acquiring information. Patients have been re-named “reflexive consumers.” At the same time, literature about the questionable reliability of web-based information has suggested the need to create both user tools that have pre-selected information and special guidelines for individuals to use to check the individual characteristics of the information they encounter. In this article, we examine suggestions that individuals must be assisted in developing skills for “reflexive consumerism” and what these particular skills should be. Using two types of data (discursive data from websites and promotional items, and supplementary data from interviews and ethnographic observations carried out with those working to sustain these initiatives), we examine how users are directly addressed and discussed. We argue that these initiatives prescribe skills and practices that extend beyond finding and assessing information on the internet and demonstrate that they include ideals of consumerism and citizenship. PMID:17972056

Information Rx: prescribing good consumerism and responsible citizenship.

PubMed

Adams, Samantha; de Bont, Antoinette

2007-12-01

Recent medical informatics and sociological literature has painted the image of a new type of patient--one that is reflexive and informed, with highly specified information needs and perceptions, as well as highly developed skills and tactics for acquiring information. Patients have been re-named "reflexive consumers." At the same time, literature about the questionable reliability of web-based information has suggested the need to create both user tools that have pre-selected information and special guidelines for individuals to use to check the individual characteristics of the information they encounter. In this article, we examine suggestions that individuals must be assisted in developing skills for "reflexive consumerism" and what these particular skills should be. Using two types of data (discursive data from websites and promotional items, and supplementary data from interviews and ethnographic observations carried out with those working to sustain these initiatives), we examine how users are directly addressed and discussed. We argue that these initiatives prescribe skills and practices that extend beyond finding and assessing information on the internet and demonstrate that they include ideals of consumerism and citizenship.

Mechanisms of migraine aura revealed by functional MRI in human visual cortex

PubMed Central

Hadjikhani, Nouchine; Sanchez del Rio, Margarita; Wu, Ona; Schwartz, Denis; Bakker, Dick; Fischl, Bruce; Kwong, Kenneth K.; Cutrer, F. Michael; Rosen, Bruce R.; Tootell, Roger B. H.; Sorensen, A. Gregory; Moskowitz, Michael A.

2001-01-01

Cortical spreading depression (CSD) has been suggested to underlie migraine visual aura. However, it has been challenging to test this hypothesis in human cerebral cortex. Using high-field functional MRI with near-continuous recording during visual aura in three subjects, we observed blood oxygenation level-dependent (BOLD) signal changes that demonstrated at least eight characteristics of CSD, time-locked to percept/onset of the aura. Initially, a focal increase in BOLD signal (possibly reflecting vasodilation), developed within extrastriate cortex (area V3A). This BOLD change progressed contiguously and slowly (3.5 ± 1.1 mm/min) over occipital cortex, congruent with the retinotopy of the visual percept. Following the same retinotopic progression, the BOLD signal then diminished (possibly reflecting vasoconstriction after the initial vasodilation), as did the BOLD response to visual activation. During periods with no visual stimulation, but while the subject was experiencing scintillations, BOLD signal followed the retinotopic progression of the visual percept. These data strongly suggest that an electrophysiological event such as CSD generates the aura in human visual cortex. PMID:11287655

The first interview: Anxieties and research on initiating psychoanalysis.

PubMed

Reith, Bernard

2015-06-01

A qualitative clinical study of preliminary interviews by the Working Party on Initiating Psychoanalysis (WPIP) of the European Psychoanalytic Federation suggests that the unconscious dynamics in first interviews are extraordinarily powerful and that they give rise to deep unconscious anxieties in both patient and analyst, with the corresponding defences against them. Furthermore, the group dynamics observed in the clinical workshops and in the research team doing the study suggest that both the anxieties and the defences are conveyed to these groups in the form of unelaborated 'session residues' provoking renewed anxieties and defences in them. These findings contribute to our understanding of what goes on in first interviews, but also raise interesting questions about the psychoanalytic research process in psychoanalysis and how confrontation with the unknown is dealt with in that context. Rather than as a means to avoid anxiety, method in clinical research can be seen as a way to help the research group to contain its reactions and to tolerate them until the group finds its way to further elaboration. These points are illustrated with a clinical case drawn from the study. Copyright © 2014 Institute of Psychoanalysis.

Double Scaling in the Relaxation Time in the β -Fermi-Pasta-Ulam-Tsingou Model

NASA Astrophysics Data System (ADS)

Lvov, Yuri V.; Onorato, Miguel

2018-04-01

We consider the original β -Fermi-Pasta-Ulam-Tsingou system; numerical simulations and theoretical arguments suggest that, for a finite number of masses, a statistical equilibrium state is reached independently of the initial energy of the system. Using ensemble averages over initial conditions characterized by different Fourier random phases, we numerically estimate the time scale of equipartition and we find that for very small nonlinearity it matches the prediction based on exact wave-wave resonant interaction theory. We derive a simple formula for the nonlinear frequency broadening and show that when the phenomenon of overlap of frequencies takes place, a different scaling for the thermalization time scale is observed. Our result supports the idea that the Chirikov overlap criterion identifies a transition region between two different relaxation time scalings.

Dynamic changes of rodent somatosensory barrel cortex are correlated with learning a novel conditioned stimulus.

PubMed

Long, John D; Carmena, Jose M

2013-05-01

The rodent somatosensory barrel cortex (S1bf) has proved a valuable model for studying neural plasticity in vivo. It has been observed that sensory deprivation or conditioning reorganizes sensory-driven activity within S1bf. These observations suggest a role for S1bf in somatosensory learning. This study evaluated the hypothesis that the response properties of extracellularly recorded neurons in S1bf would change as subjects learned to respond to stimulation of S1bf. Intracortical microstimulation (ICMS) of S1bf was used as a means for bypassing feedforward drive from the sensory periphery, midbrain, and thalamus while exciting local cortical networks. To separate the learning of this conditioned stimulus-conditioned response (CS-CR) from other elements of the task, we employed a cross-modal transfer schedule. Long-Evans rats were initially trained to respond to an auditory stimulus. All subjects were then implanted in both S1bfs with chronic microwire arrays for recording neural activity and delivering ICMS. Next, this association was transferred to ICMS of one hemisphere's S1bf. S1bf responded to ICMS with a brief increase in firing rate followed by a longer reduction in activity. We observed that the duration of reduced activity elicited by ICMS increased as the subjects began to respond correctly more often than expected by chance, and the magnitude of the initial positive response increased as they consolidated this CS-CR. Subsequent ICMS of the opposite S1bf revealed that this CS-CR did not generalize across hemispheres. These results suggest that a mechanism involving a single hemisphere's S1bf tunes cortical responses in concert with changes in rodent behavior during somatosensory learning.

Radio Observations of the Tidal Disruption Event XMMSL1 J0740-85

NASA Astrophysics Data System (ADS)

Alexander, K. D.; Wieringa, M. H.; Berger, E.; Saxton, R. D.; Komossa, S.

2017-03-01

We present radio observations of the tidal disruption event candidate (TDE) XMMSL1 J0740-85 spanning 592 to 875 days post X-ray discovery. We detect radio emission that fades from an initial peak flux density at 1.6 GHz of 1.19 ± 0.06 mJy to 0.65 ± 0.06 mJy, suggesting an association with the TDE. This makes XMMSL1 J0740-85 at d = 75 Mpc the nearest TDE with detected radio emission to date and only the fifth TDE with radio emission overall. The observed radio luminosity rules out a powerful relativistic jet like that seen in the relativistic TDE Swift J1644+57. Instead, we infer from an equipartition analysis that the radio emission most likely arises from a non-relativistic outflow similar to that seen in the nearby TDE ASASSN-14li, with a velocity of about 104 km s-1 and a kinetic energy of about 1048 erg, expanding into a medium with a density of about 102 cm-3. Alternatively, the radio emission could arise from a weak initially relativistic but decelerated jet with an energy of ˜ 2× {10}50 erg, or (for an extreme disruption geometry) from the unbound debris. The radio data for XMMSL1 J0740-85 continues to support the previous suggestion of a bimodal distribution of common non-relativistic isotropic outflows and rare relativistic jets in TDEs (in analogy with the relation between Type Ib/c supernovae and long-duration gamma-ray bursts). The radio data also provide a new measurement of the circumnuclear density on a sub-parsec scale around an extragalactic supermassive black hole.

On the formation and evolution of sinuous rilles: Morphologic and morphometric insights from the Marius Hills and Aristarchus Plateau regions

NASA Astrophysics Data System (ADS)

Roberts, Carolyn Eve

Lunar sinuous rilles are characteristically long (100-350 km), narrow (< 1 km wide) volcanic channels that shallow distally from their source. Despite the vast knowledge accumulated over decades of lunar exploration, sinuous rille formation remains poorly understood. To constrain formation processes, the morphology and morphometry of many rilles were examined using Lunar Orbiter IV/V and Lunar Reconnaissance Orbiter imagery. Morphologic observations suggest that sinuous rilles initially formed within expansive sheet flows as preferred pathways along the pre-eruptive surface that developed into lava tubes as the eruption continued. Geologic sketch maps reveal outcrop layering, exposed in rille walls, that is consistent with sheet flow emplacement and small, anastomosing "rillettes" around Rima Marius, suggesting that initial tubes intermingled and coalesced to form larger tubes. From terrestrial basalt flow emplacement observations, I infer that as the outer boundaries of the Rima Marius-forming sheet flow cooled, the remaining lava was forced toward the main tube and downcutting transpired at the flow base. Once the eruption concluded, lava drained out of the main tube; the dimensions of the hollow tube lead to roof collapse, resulting in the general rille structure observed today. Results from the morphometric analysis indicate that sinuous rille characteristics (length, width, sinuosity, radius of curvature, number of curves, and fractal dimension) are similar between the two highest lunar sinuous rille populations at Marius Hills and Aristarchus Plateau. Moreover, the number of curves increases linearly with rille length and a weak correlation exists between sinuosity and fractal dimension. Compared to terrestrial rivers, sinuous rilles have lower amplitudes, smaller sinuosity values and fractal dimension values. The preponderance of evidence indicates sinuous rilles formed through a combination of both constructional and erosional processes.

Frictional behavior of large displacement experimental faults

USGS Publications Warehouse

Beeler, N.M.; Tullis, T.E.; Blanpied, M.L.; Weeks, J.D.

1996-01-01

The coefficient of friction and velocity dependence of friction of initially bare surfaces and 1-mm-thick simulated fault gouges (400 mm at 25??C and 25 MPa normal stress. Steady state negative friction velocity dependence and a steady state fault zone microstructure are achieved after ???18 mm displacement, and an approximately constant strength is reached after a few tens of millimeters of sliding on initially bare surfaces. Simulated fault gouges show a large but systematic variation of friction, velocity dependence of friction, dilatancy, and degree of localization with displacement. At short displacement (<10 mm), simulated gouge is strong, velocity strengthening and changes in sliding velocity are accompanied by relatively large changes in dilatancy rate. With continued displacement, simulated gouges become progressively weaker and less velocity strengthening, the velocity dependence of dilatancy rate decreases, and deformation becomes localized into a narrow basal shear which at its most localized is observed to be velocity weakening. With subsequent displacement, the fault restrengthens, returns to velocity strengthening, or to velocity neutral, the velocity dependence of dilatancy rate becomes larger, and deformation becomes distributed. Correlation of friction, velocity dependence of friction and of dilatancy rate, and degree of localization at all displacements in simulated gouge suggest that all quantities are interrelated. The observations do not distinguish the independent variables but suggest that the degree of localization is controlled by the fault strength, not by the friction velocity dependence. The friction velocity dependence and velocity dependence of dilatancy rate can be used as qualitative measures of the degree of localization in simulated gouge, in agreement with previous studies. Theory equating the friction velocity dependence of simulated gouge to the sum of the friction velocity dependence of bare surfaces and the velocity dependence of dilatancy rate of simulated gouge fails to quantitatively account for the experimental observations.

Modelling size-dependent cannibalism in barramundi Lates calcarifer: cannibalistic polyphenism and its implication to aquaculture.

PubMed

Ribeiro, Flavio F; Qin, Jian G

2013-01-01

This study quantified size-dependent cannibalism in barramundi Lates calcarifer through coupling a range of prey-predator pairs in a different range of fish sizes. Predictive models were developed using morphological traits with the alterative assumption of cannibalistic polyphenism. Predictive models were validated with the data from trials where cannibals were challenged with progressing increments of prey sizes. The experimental observations showed that cannibals of 25-131 mm total length could ingest the conspecific prey of 78-72% cannibal length. In the validation test, all predictive models underestimate the maximum ingestible prey size for cannibals of a similar size range. However, the model based on the maximal mouth width at opening closely matched the empirical observations, suggesting a certain degree of phenotypic plasticity of mouth size among cannibalistic individuals. Mouth size showed allometric growth comparing with body depth, resulting in a decreasing trend on the maximum size of ingestible prey as cannibals grow larger, which in parts explains why cannibalism in barramundi is frequently observed in the early developmental stage. Any barramundi has the potential to become a cannibal when the initial prey size was <50% of the cannibal body length, but fish could never become a cannibal when prey were >58% of their size, suggesting that 50% of size difference can be the threshold to initiate intracohort cannibalism in a barramundi population. Cannibalistic polyphenism was likely to occur in barramundi that had a cannibalistic history. An experienced cannibal would have a greater ability to stretch its mouth size to capture a much larger prey than the models predict. The awareness of cannibalistic polyphenism has important application in fish farming management to reduce cannibalism.

Modelling Size-Dependent Cannibalism in Barramundi Lates calcarifer: Cannibalistic Polyphenism and Its Implication to Aquaculture

PubMed Central

Ribeiro, Flavio F.; Qin, Jian G.

2013-01-01

This study quantified size-dependent cannibalism in barramundi Lates calcarifer through coupling a range of prey-predator pairs in a different range of fish sizes. Predictive models were developed using morphological traits with the alterative assumption of cannibalistic polyphenism. Predictive models were validated with the data from trials where cannibals were challenged with progressing increments of prey sizes. The experimental observations showed that cannibals of 25–131 mm total length could ingest the conspecific prey of 78–72% cannibal length. In the validation test, all predictive models underestimate the maximum ingestible prey size for cannibals of a similar size range. However, the model based on the maximal mouth width at opening closely matched the empirical observations, suggesting a certain degree of phenotypic plasticity of mouth size among cannibalistic individuals. Mouth size showed allometric growth comparing with body depth, resulting in a decreasing trend on the maximum size of ingestible prey as cannibals grow larger, which in parts explains why cannibalism in barramundi is frequently observed in the early developmental stage. Any barramundi has the potential to become a cannibal when the initial prey size was <50% of the cannibal body length, but fish could never become a cannibal when prey were >58% of their size, suggesting that 50% of size difference can be the threshold to initiate intracohort cannibalism in a barramundi population. Cannibalistic polyphenism was likely to occur in barramundi that had a cannibalistic history. An experienced cannibal would have a greater ability to stretch its mouth size to capture a much larger prey than the models predict. The awareness of cannibalistic polyphenism has important application in fish farming management to reduce cannibalism. PMID:24349295

Recognition and attention guidance during contextual cueing in real-world scenes: evidence from eye movements.

PubMed

Brockmole, James R; Henderson, John M

2006-07-01

When confronted with a previously encountered scene, what information is used to guide search to a known target? We contrasted the role of a scene's basic-level category membership with its specific arrangement of visual properties. Observers were repeatedly shown photographs of scenes that contained consistently but arbitrarily located targets, allowing target positions to be associated with scene content. Learned scenes were then unexpectedly mirror reversed, spatially translating visual features as well as the target across the display while preserving the scene's identity and concept. Mirror reversals produced a cost as the eyes initially moved toward the position in the display in which the target had previously appeared. The cost was not complete, however; when initial search failed, the eyes were quickly directed to the target's new position. These results suggest that in real-world scenes, shifts of attention are initially based on scene identity, and subsequent shifts are guided by more detailed information regarding scene and object layout.

Evaluation of Event Physical Activity Engagement at an Open Streets Initiative Within a Texas-Mexico Border Town.

PubMed

Salazar-Collier, Cindy Lynn; Reininger, Belinda; Gowen, Rose; Rodriguez, Arturo; Wilkinson, Anna

2018-05-09

Open streets initiatives provide an opportunity to engage in physical activity (PA) freely by temporarily closing streets to motorized traffic. Route counting estimation and event intercept surveys (n = 682) were conducted across 4 CycloBia events in Brownsville, TX, in 2015 to determine sociodemographics, PA engagement at the event, event awareness, and past CycloBia attendance. Cycling was the most commonly observed activity along the route (73.6%) followed by walking (22.9%). Attendees self-reported a median of 120 minutes in PA with 17.3% of attendees meeting recommended weekly PA guidelines at the event. Significant predictors of meeting PA guidelines via event PA engagement were past event attendance, sex, age, and Hispanic ethnicity. Findings suggest that CycloBia reached a large, low-income, predominantly Hispanic population and may be effective in promoting PA. Results help understand the effect of an open streets initiative on attendees living in a midsize, border city.

Logistic Mixed Models to Investigate Implicit and Explicit Belief Tracking.

PubMed

Lages, Martin; Scheel, Anne

2016-01-01

We investigated the proposition of a two-systems Theory of Mind in adults' belief tracking. A sample of N = 45 participants predicted the choice of one of two opponent players after observing several rounds in an animated card game. Three matches of this card game were played and initial gaze direction on target and subsequent choice predictions were recorded for each belief task and participant. We conducted logistic regressions with mixed effects on the binary data and developed Bayesian logistic mixed models to infer implicit and explicit mentalizing in true belief and false belief tasks. Although logistic regressions with mixed effects predicted the data well a Bayesian logistic mixed model with latent task- and subject-specific parameters gave a better account of the data. As expected explicit choice predictions suggested a clear understanding of true and false beliefs (TB/FB). Surprisingly, however, model parameters for initial gaze direction also indicated belief tracking. We discuss why task-specific parameters for initial gaze directions are different from choice predictions yet reflect second-order perspective taking.

Initial sediment transport model of the mining-affected Aries River Basin, Romania

USGS Publications Warehouse

Friedel, Michael J.; Linard, Joshua I.

2008-01-01

The Romanian government is interested in understanding the effects of existing and future mining activities on long-term dispersal, storage, and remobilization of sediment-associated metals. An initial Soil and Water Assessment Tool (SWAT) model was prepared using available data to evaluate hypothetical failure of the Valea Sesei tailings dam at the Rosia Poieni mine in the Aries River basin. Using the available data, the initial Aries River Basin SWAT model could not be manually calibrated to accurately reproduce monthly streamflow values observed at the Turda gage station. The poor simulation of the monthly streamflow is attributed to spatially limited soil and precipitation data, limited constraint information due to spatially and temporally limited streamflow measurements, and in ability to obtain optimal parameter values when using a manual calibration process. Suggestions to improve the Aries River basin sediment transport model include accounting for heterogeneity in model input, a two-tier nonlinear calibration strategy, and analysis of uncertainty in predictions.

Can a man-made universe be achieved by quantum tunneling without an initial singularity?

NASA Technical Reports Server (NTRS)

Guth, Alan H.; Haller, K. (Editor); Caldi, D. B. (Editor); Islam, M. M. (Editor); Mallett, R. L. (Editor); Mannheim, P. D. (Editor); Swanson, M. S. (Editor)

1991-01-01

Essentially all modern particle theories suggest the possible existence of a false vacuum state; a metastable state with an energy density that cannot be lowered except by means of a very slow phase transition. Inflationary cosmology makes use of such a state to drive the expansion of the big bang, allowing the entire observed universe to evolve from a very small initial mass. A sphere of false vacuum in the present universe, if larger than a certain critical mass, could inflate to form a new universe which would rapidly detach from its parent. A false vacuum bubble of this size, however, cannot be produced classically unless an initial singularity is present from the outset. The possibility is explored that a bubble of subcritical size, which classically would evolve to a maximum size and collapse, might instead tunnel through a barrier to produce a new universe. The tunneling rate using semiclassical quantum gravity is estimated, and some interesting ambiguities in the formulas are discovered.

Characterizing rare-event property distributions via replicate molecular dynamics simulations of proteins.

PubMed

Krishnan, Ranjani; Walton, Emily B; Van Vliet, Krystyn J

2009-11-01

As computational resources increase, molecular dynamics simulations of biomolecules are becoming an increasingly informative complement to experimental studies. In particular, it has now become feasible to use multiple initial molecular configurations to generate an ensemble of replicate production-run simulations that allows for more complete characterization of rare events such as ligand-receptor unbinding. However, there are currently no explicit guidelines for selecting an ensemble of initial configurations for replicate simulations. Here, we use clustering analysis and steered molecular dynamics simulations to demonstrate that the configurational changes accessible in molecular dynamics simulations of biomolecules do not necessarily correlate with observed rare-event properties. This informs selection of a representative set of initial configurations. We also employ statistical analysis to identify the minimum number of replicate simulations required to sufficiently sample a given biomolecular property distribution. Together, these results suggest a general procedure for generating an ensemble of replicate simulations that will maximize accurate characterization of rare-event property distributions in biomolecules.

78 FR 32406 - Submission for OMB Review; 30-Day Comment Request: Women's Health Initiative Observational Study

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-30

...; 30-Day Comment Request: Women's Health Initiative Observational Study SUMMARY: Under the provisions... proposed project contact: Shari Eason Ludlam, Project Officer, Women's Health Initiative Program Office... additional plans and instruments must be requested in writing. Proposed Collection: Women's Health Initiative...

Post-conflict affiliation as conflict management in captive bottlenose dolphins (Tursiops truncatus)

PubMed Central

Yamamoto, Chisato; Morisaka, Tadamichi; Furuta, Keisuke; Ishibashi, Toshiaki; Yoshida, Akihiko; Taki, Michihiro; Mori, Yoshihisa; Amano, Masao

2015-01-01

Post-conflict affiliation between former opponents or between one of the former opponents and bystanders might have the function of conflict management, which reduces the costs associated with aggressions. One of the suggested functions of post-conflict affiliation is decreased renewed aggressions directed from aggressors to victims. However, the effect of post-conflict affiliation on renewed aggressions by victims has not been investigated. We examined whether post-conflict affiliations decreased the number of renewed aggressions initiated by winners or losers in captive bottlenose dolphins. Both winners and losers initiated renewed aggressions. However, these aggressions decreased after post-conflict affiliation between former opponents, initiated by bystanders to winners, initiated by losers to bystanders, and initiated by bystanders to losers. Post-conflict affiliation between former opponents is suggested to function as reconciliation. Post–conflict affiliation initiated by losers to bystanders is suggested to function as the protection of losers. Post-conflict affiliations initiated by bystanders to one of former opponents are suggested to function as both appeasement and protection of the opponent who affiliates with bystanders. PMID:26392064

Post-conflict affiliation as conflict management in captive bottlenose dolphins (Tursiops truncatus).

PubMed

Yamamoto, Chisato; Morisaka, Tadamichi; Furuta, Keisuke; Ishibashi, Toshiaki; Yoshida, Akihiko; Taki, Michihiro; Mori, Yoshihisa; Amano, Masao

2015-09-22

Post-conflict affiliation between former opponents or between one of the former opponents and bystanders might have the function of conflict management, which reduces the costs associated with aggressions. One of the suggested functions of post-conflict affiliation is decreased renewed aggressions directed from aggressors to victims. However, the effect of post-conflict affiliation on renewed aggressions by victims has not been investigated. We examined whether post-conflict affiliations decreased the number of renewed aggressions initiated by winners or losers in captive bottlenose dolphins. Both winners and losers initiated renewed aggressions. However, these aggressions decreased after post-conflict affiliation between former opponents, initiated by bystanders to winners, initiated by losers to bystanders, and initiated by bystanders to losers. Post-conflict affiliation between former opponents is suggested to function as reconciliation. Post-conflict affiliation initiated by losers to bystanders is suggested to function as the protection of losers. Post-conflict affiliations initiated by bystanders to one of former opponents are suggested to function as both appeasement and protection of the opponent who affiliates with bystanders.

Observation learning versus physical practice leads to different consolidation outcomes in a movement timing task.

PubMed

Trempe, Maxime; Sabourin, Maxime; Rohbanfard, Hassan; Proteau, Luc

2011-03-01

Motor learning is a process that extends beyond training sessions. Specifically, physical practice triggers a series of physiological changes in the CNS that are regrouped under the term "consolidation" (Stickgold and Walker 2007). These changes can result in between-session improvement or performance stabilization (Walker 2005). In a series of three experiments, we tested whether consolidation also occurs following observation. In Experiment 1, participants observed an expert model perform a sequence of arm movements. Although we found evidence of observation learning, no significant difference was revealed between participants asked to reproduce the observed sequence either 5 min or 24 h later (no between-session improvement). In Experiment 2, two groups of participants observed an expert model perform two distinct movement sequences (A and B) either 10 min or 8 h apart; participants then physically performed both sequences after a 24-h break. Participants in the 8-h group performed Sequence B less accurately compared to participants in the 5-min group, suggesting that the memory representation of the first sequence had been stabilized and that it interfered with the learning of the second sequence. Finally, in Experiment 3, the initial observation phase was replaced by a physical practice phase. In contrast with the results of Experiment 2, participants in the 8-h group performed Sequence B significantly more accurately compared to participants in the 5-min group. Together, our results suggest that the memory representation of a skill learned through observation undergoes consolidation. However, consolidation of an observed motor skill leads to distinct behavioural outcomes in comparison with physical practice.

Comparison of Dawn and Dusk Precipitating Electron Energy Populations Shortly After the Initial Shock for the January 10th, 1997 Magnetic Cloud

NASA Technical Reports Server (NTRS)

Spann, J.; Germany, G.; Swift, W.; Parks, G.; Brittnacher, M.; Elsen, R.

1997-01-01

The observed precipitating electron energy between 0130 UT and 0400 UT of January 10 th, 1997, indicates that there is a more energetic precipitating electron population that appears in the auroral oval at 1800-2200 UT at 030) UT. This increase in energy occurs after the initial shock of the magnetic cloud reaches the Earth (0114 UT) and after faint but dynamic polar cap precipitation has been cleared out. The more energetic population is observed to remain rather constant in MLT through the onset of auroral activity (0330 UT) and to the end of the Polar spacecraft apogee pass. Data from the Ultraviolet Imager LBH long and LBH short images are used to quantify the average energy of the precipitating auroral electrons. The Wind spacecraft located about 100 RE upstream monitored the IMF and plasma parameters during the passing of the cloud. The affects of oblique angle viewing are included in the analysis. Suggestions as to the source of this hot electron population will be presented.

Hypercorrection of high confidence errors in lexical representations.

PubMed

Iwaki, Nobuyoshi; Matsushima, Hiroko; Kodaira, Kazumasa

2013-08-01

Memory errors associated with higher confidence are more likely to be corrected than errors made with lower confidence, a phenomenon called the hypercorrection effect. This study investigated whether the hypercorrection effect occurs with phonological information of lexical representations. In Experiment 1, 15 participants performed a Japanese Kanji word-reading task, in which the words had several possible pronunciations. In the initial task, participants were required to read aloud each word and indicate their confidence in their response; this was followed by receipt of visual feedback of the correct response. A hypercorrection effect was observed, indicating generality of this effect beyond previous observations in memories based upon semantic or episodic representations. This effect was replicated in Experiment 2, in which 40 participants performed the same task as in Experiment 1. When the participant's ratings of the practical value of the words were controlled, a partial correlation between confidence and likelihood of later correcting the initial mistaken response was reduced. This suggests that the hypercorrection effect may be partially caused by an individual's recognition of the practical value of reading the words correctly.

Temporally resolved plasma spectroscopy for analyzing natural gas components

NASA Astrophysics Data System (ADS)

Kobayashi, Kazunobu; Tsumaki, Naomasa; Ito, Tsuyohito

2016-09-01

Temporally resolved plasma spectroscopy has been carried out in two different hydrocarbon gas mixtures (CH4/Ar and C2H6/Ar) to explore the possibility of a new gas sensor using plasma emission spectral analysis. In this experiment, a nanosecond-pulsed plasma discharge was applied to observe optical emissions representing the initial molecular structure. It is found that a CH emission intensity in CH4/Ar is higher than that in C2H6/Ar. On the other hand, C2 intensities are almost the same degree between CH4/Ar and C2H6/Ar. This finding indicates that the emission intensity ratio of CH to C2 might be an effective index for a gas analysis. In addition, a time for the highest emission intensities of CH and C2 is several nanoseconds later than that of Ar. This result suggests that spectra from the initial molecular structure may be observed at the early stage of the discharge before molecules are fully dissociated, and this is currently in progress.

The ontogenetic ritualization of bonobo gestures.

PubMed

Halina, Marta; Rossano, Federico; Tomasello, Michael

2013-07-01

Great apes communicate with gestures in flexible ways. Based on several lines of evidence, Tomasello and colleagues have posited that many of these gestures are learned via ontogenetic ritualization-a process of mutual anticipation in which particular social behaviors come to function as intentional communicative signals. Recently, Byrne and colleagues have argued that all great ape gestures are basically innate. In the current study, for the first time, we attempted to observe the process of ontogenetic ritualization as it unfolds over time. We focused on one communicative function between bonobo mothers and infants: initiation of "carries" for joint travel. We observed 1,173 carries in ten mother-infant dyads. These were initiated by nine different gesture types, with mothers and infants using many different gestures in ways that reflected their different roles in the carry interaction. There was also a fair amount of variability among the different dyads, including one idiosyncratic gesture used by one infant. This gestural variation could not be attributed to sampling effects alone. These findings suggest that ontogenetic ritualization plays an important role in the origin of at least some great ape gestures.

Extended Kalman Doppler tracking and model determination for multi-sensor short-range radar

NASA Astrophysics Data System (ADS)

Mittermaier, Thomas J.; Siart, Uwe; Eibert, Thomas F.; Bonerz, Stefan

2016-09-01

A tracking solution for collision avoidance in industrial machine tools based on short-range millimeter-wave radar Doppler observations is presented. At the core of the tracking algorithm there is an Extended Kalman Filter (EKF) that provides dynamic estimation and localization in real-time. The underlying sensor platform consists of several homodyne continuous wave (CW) radar modules. Based on In-phase-Quadrature (IQ) processing and down-conversion, they provide only Doppler shift information about the observed target. Localization with Doppler shift estimates is a nonlinear problem that needs to be linearized before the linear KF can be applied. The accuracy of state estimation depends highly on the introduced linearization errors, the initialization and the models that represent the true physics as well as the stochastic properties. The important issue of filter consistency is addressed and an initialization procedure based on data fitting and maximum likelihood estimation is suggested. Models for both, measurement and process noise are developed. Tracking results from typical three-dimensional courses of movement at short distances in front of a multi-sensor radar platform are presented.

Bak Conformational Changes Induced by Ligand Binding: Insight into BH3 Domain Binding and Bak Homo-Oligomerization

PubMed Central

Pang, Yuan-Ping; Dai, Haiming; Smith, Alyson; Meng, X. Wei; Schneider, Paula A.; Kaufmann, Scott H.

2012-01-01

Recently we reported that the BH3-only proteins Bim and Noxa bind tightly but transiently to the BH3-binding groove of Bak to initiate Bak homo-oligomerization. However, it is unclear how such tight binding can induce Bak homo-oligomerization. Here we report the ligand-induced Bak conformational changes observed in 3D models of Noxa·Bak and Bim·Bak refined by molecular dynamics simulations. In particular, upon binding to the BH3-binding groove, Bim and Noxa induce a large conformational change of the loop between helices 1 and 2 and in turn partially expose a remote groove between helices 1 and 6 in Bak. These observations, coupled with the reported experimental data, suggest formation of a pore-forming Bak octamer, in which the BH3-binding groove is at the interface on one side of each monomer and the groove between helices 1 and 6 is at the interface on the opposite side, initiated by ligand binding to the BH3-binding groove. PMID:22355769

Assessment of Data Assimilation with the Prototype High Resolution Rapid Refresh for Alaska (HRRRAK)

NASA Technical Reports Server (NTRS)

Harrison, Kayla; Morton, Don; Zavodsky, Brad; Chou, Shih

2012-01-01

The Arctic Region Supercomputing Center has been running a quasi-operational prototype of a High Resolution Rapid Refresh for Alaska (HRRRAK) at 3km resolution, initialized by the 13km Rapid Refresh (RR). Although the RR assimilates a broad range of observations into its analyses, experiments with the HRRRAK suggest that there may be added value in assimilating observations into the 3km initial conditions, downscaled from the 13km RR analyses. The NASA Short-term Prediction Research and Transition (SPoRT) group has been using assimilated data from the Atmospheric Infrared Sounder (AIRS) in WRF and WRF-Var simulations since 2004 with promising results. The sounder is aboard NASA s Aqua satellite, and provides vertical profiles of temperature and humidity. The Gridpoint Statistical Interpolation (GSI) system is then used to assimilate these vertical profiles into WRF forecasts. In this work, we assess the use of AIRS data in combination with other global data assimilation products on non-assimilated HRRRAK case studies. Two separate weather events will be assessed to qualitatively and quantitatively assess the impacts of AIRS data on HRRRAK forecasts.

[Petrological Analysis of Astrophysical Dust Analog Evolution

NASA Technical Reports Server (NTRS)

Rietmeijer, Frans J. M.

1997-01-01

This project "Petrological analysis of astrophysical dust analog evolution" was initiated to try to understand the vapor phase condensation, and the nature of the reaction products, in circumstellar environments, such as the solar nebula 4,500 Myrs ago, and in the interstellar medium. Telescope-based infrared [IR] spectroscopy offers a broad-scale inventory of the various types of dust in these environments but no details on small-scale variations in terms of chemistry and morphology and petrological phase relationships. Vapor phase condensation in these environments is almost certainly a non-equilibrium process. The main challenge to this research was to document the nature of this process that, based on astrophysical observations, seems to yield compositionally consistent materials. This observation may suggest a predictable character during non-equilibrium condensation. These astrophysical environments include two chemically distinct, that is, oxygen-rich and carbon-rich environments. The former is characterized by silicates the latter by carbon-bearing solids. According to cosmological models of stellar evolution circumstellar dust accreted into protoplanets wherein thermal and/or aqueous processes will alter the dust under initially, non-equilibrium conditions.

Inter-observer variability in diagnosing radiological features of aneurysmal subarachnoid hemorrhage; a preliminary single centre study comparing observers from different specialties and levels of training.

PubMed

Siddiqui, Usman T; Khan, Anjum F; Shamim, Muhammad Shahzad; Hamid, Rana Shoaib; Alam, Muhammad Mehboob; Emaduddin, Muhammad

2014-01-01

A noncontrast computed tomography (CT) scan remains the initial radiological investigation of choice for a patient with suspected aneurysmal subarachnoid hemorrhage (aSAH). This initial scan may be used to derive key information about the underlying aneurysm which may aid in further management. The interpretation, however, is subject to the skill and experience of the interpreting individual. The authors here evaluate the interpretation of such CT scans by different individuals at different levels of training, and in two different specialties (Radiology and Neurosurgery). Initial nonontrast CT scan of 35 patients with aSAH was evaluated independently by four different observers. The observers selected for the study included two from Radiology and two from Neurosurgery at different levels of training; a resident currently in mid training and a resident who had recently graduated from training of each specialty. Measured variables included interpreter's suspicion of presence of subarachnoid blood, side of the subarachnoid hemorrhage, location of the aneurysm, the aneurysm's proximity to vessel bifurcation, number of aneurysm(s), contour of aneurysm(s), presence of intraventricular hemorrhage (IVH), intracerebral hemorrhage (ICH), infarction, hydrocephalus and midline shift. To determine the inter-observer variability (IOV), weighted kappa values were calculated. There was moderate agreement on most of the CT scan findings among all observers. Substantial agreement was found amongst all observers for hydrocephalus, IVH, and ICH. Lowest agreement rates were seen in the location of aneurysm being supra or infra tentorial. There were, however, some noteworthy exceptions. There was substantial to almost perfect agreement between the radiology graduate and radiology resident on most CT findings. The lowest agreement was found between the neurosurgery graduate and the radiology graduate. Our study suggests that although agreements were seen in the interpretation of some of the radiological features of aSAH, there is still considerable IOV in the interpretation of most features among physicians belonging to different levels of training and different specialties. Whether these might affect management or outcome is unclear.

Evaluating the impacts of triclosan on wastewater treatment performance during startup and acclimation.

PubMed

Holzem, R M; Gardner, C M; Gunsch, C K

2018-01-01

Triclosan (TCS) is a broad range antimicrobial agent used in many personal care products, which is commonly discharged to wastewater treatment facilities (WWTFs). This study examined the impact of TCS on wastewater treatment performance using laboratory bench-scale sequencing batch reactors (SBRs) coupled with anaerobic digesters. The SBRs were continuously fed synthetic wastewater amended with or without 0.68 μM TCS, with the aim of determining the effect of chronic TCS exposure as opposed to a pulse TCS addition as previously studied. Overall, the present study suggests inhibition of nitrogen removal during reactor startup. However, NH 4 + removal fully rebounded after 63 days, suggesting acclimation of the associated microbial communities to TCS. An initial decrease in microbial community diversity was observed in the SBRs fed TCS as compared to the control SBRs, followed by an increase in community diversity, which coincided with the increase in NH 4 + removal. Elevated levels of NO 3 - and NO 2 - were found in the reactor effluent after day 58, however, suggesting ammonia oxidizing bacteria rebounding more rapidly than nitrogen oxidizing bacteria. Similar effects on treatment efficiencies at actual WWTFs have not been widely observed, suggesting that continuous addition of TCS in their influent may have selected for TCS-resistant nitrogen oxidizing bacteria.

Parameters affecting the inhibition of Candida albicans GDH 2023 and GRI 2773 blastospore viability by purified synthetic salivary histidine-rich polypeptides.

PubMed

Santarpia, R P; Cho, M I; Pollock, J J

1990-08-01

Purified synthetic salivary histidine-rich polypeptides, HRPs 2, 3, 4, 5, and 6, were observed to inhibit Candida albicans blastospore viability at yeast cell concentrations ranging from 10(2) to greater than 10(6) colony forming units per ml. Among the HRPs, HRP-4 was the best inhibitor with significant killing activity noted at a peptide concentration of 0.5 microgram per ml. Antifungal potency under growth conditions was observed to be dependent upon pH. In contrast, killing did not vary throughout the pH range tested under non-growth conditions. Electron microscopy results demonstrated HRP damage at pH 5 which appeared to be initiated at the membrane. At pH 7.4, micrographs revealed clear evidence of intracellular destruction suggesting more extensive damage at neutral as compared to acidic pH. These results suggest that within the changing realm of the oral cavity, the HRPs would be expected to be potent killers of C. albicans.

Saliency Changes Appearance

PubMed Central

Kerzel, Dirk; Schönhammer, Josef; Burra, Nicolas; Born, Sabine; Souto, David

2011-01-01

Numerous studies have suggested that the deployment of attention is linked to saliency. In contrast, very little is known about how salient objects are perceived. To probe the perception of salient elements, observers compared two horizontally aligned stimuli in an array of eight elements. One of them was salient because of its orientation or direction of motion. We observed that the perceived luminance contrast or color saturation of the salient element increased: the salient stimulus looked even more salient. We explored the possibility that changes in appearance were caused by attention. We chose an event-related potential indexing attentional selection, the N2pc, to answer this question. The absence of an N2pc to the salient object provides preliminary evidence against involuntary attentional capture by the salient element. We suggest that signals from a master saliency map flow back into individual feature maps. These signals boost the perceived feature contrast of salient objects, even on perceptual dimensions different from the one that initially defined saliency. PMID:22162760

Genomic mapping of single-stranded DNA in hydroxyurea-challenged yeasts identifies origins of replication.

PubMed

Feng, Wenyi; Collingwood, David; Boeck, Max E; Fox, Lindsay A; Alvino, Gina M; Fangman, Walton L; Raghuraman, Mosur K; Brewer, Bonita J

2006-02-01

During DNA replication one or both strands transiently become single stranded: first at the sites where initiation of DNA synthesis occurs (known as origins of replication) and subsequently on the lagging strands of replication forks as discontinuous Okazaki fragments are generated. We report a genome-wide analysis of single-stranded DNA (ssDNA) formation in the presence of hydroxyurea during DNA replication in wild-type and checkpoint-deficient rad53 Saccharomyces cerevisiae cells. In wild-type cells, ssDNA was first observed at a subset of replication origins and later 'migrated' bi-directionally, suggesting that ssDNA formation is associated with continuously moving replication forks. In rad53 cells, ssDNA was observed at virtually every known origin, but remained there over time, suggesting that replication forks stall. Telomeric regions seemed to be particularly sensitive to the loss of Rad53 checkpoint function. Replication origins in Schizosaccharomyces pombe were also mapped using our method.

New estimates for Io eruption temperatures: Implications for the interior

USGS Publications Warehouse

Keszthelyi, L.; Jaeger, W.; Milazzo, M.; Radebaugh, J.; Davies, A.G.; Mitchell, K.L.

2007-01-01

The initial interpretation of Galileo data from Jupiter's moon, Io, suggested eruption temperatures ≥1600°C. Tidal heating models have difficulties explaining Io's prodigious heat flow if the mantle is >1300°C, although we suggest that temperatures up to ~1450°C may be possible. In general, Io eruption temperatures have been overestimated because the incorrect thermal model has been applied. Much of the thermal emission from high-temperature hot spots comes from lava fountains but lava flow models were utilized. We apply a new lava fountain model to the highest reported eruption temperature, the SSI observation of the 1997 eruption at Pillan. This resets the lower temperature limit for the eruption from ~1600 to ~1340°C . Additionally, viscous heating of the magma may have increased eruption temperature by ~50-100°C as a result of the strong compressive stresses in the ionian lithosphere. While further work is needed, it appears that the discrepancy between observations and interior models is largely resolved.

The effects of the initial mass function on the chemical evolution of elliptical galaxies

NASA Astrophysics Data System (ADS)

De Masi, Carlo; Matteucci, F.; Vincenzo, F.

2018-03-01

We describe the use of our chemical evolution model to reproduce the abundance patterns observed in a catalogue of elliptical galaxies from the Sloan Digital Sky Survey Data Release 4. The model assumes ellipticals form by fast gas accretion, and suffer a strong burst of star formation followed by a galactic wind, which quenches star formation. Models with fixed initial mass function (IMF) failed in simultaneously reproducing the observed trends with the galactic mass. So, we tested a varying IMF; contrary to the diffused claim that the IMF should become bottom heavier in more massive galaxies, we find a better agreement with data by assuming an inverse trend, where the IMF goes from being bottom heavy in less massive galaxies to top heavy in more massive ones. This naturally produces a downsizing in star formation, favouring massive stars in largest galaxies. Finally, we tested the use of the integrated Galactic IMF, obtained by averaging the canonical IMF over the mass distribution function of the clusters where star formation is assumed to take place. We combined two prescriptions, valid for different SFR regimes, to obtain the Integrated Initial Mass Function values along the whole evolution of the galaxies in our models. Predicted abundance trends reproduce the observed slopes, but they have an offset relative to the data. We conclude that bottom-heavier IMFs do not reproduce the properties of the most massive ellipticals, at variance with previous suggestions. On the other hand, an IMF varying with galactic mass from bottom heavier to top heavier should be preferred.

Knowledgeable Lemurs Become More Central in Social Networks.

PubMed

Kulahci, Ipek G; Ghazanfar, Asif A; Rubenstein, Daniel I

2018-04-23

Strong relationships exist between social connections and information transmission [1-9], where individuals' network position plays a key role in whether or not they acquire novel information [2, 3, 5, 6]. The relationships between social connections and information acquisition may be bidirectional if learning novel information, in addition to being influenced by it, influences network position. Individuals who acquire information quickly and use it frequently may receive more affiliative behaviors [10, 11] and may thus have a central network position. However, the potential influence of learning on network centrality has not been theoretically or empirically addressed. To bridge this epistemic gap, we investigated whether ring-tailed lemurs' (Lemur catta) centrality in affiliation networks changed after they learned how to solve a novel foraging task. Lemurs who had frequently initiated interactions and approached conspecifics before the learning experiment were more likely to observe and learn the task solution. Comparing social networks before and after the learning experiment revealed that the frequently observed lemurs received more affiliative behaviors than they did before-they became more central after the experiment. This change persisted even after the task was removed and was not caused by the observed lemurs initiating more affiliative behaviors. Consequently, quantifying received and initiated interactions separately provides unique insights into the relationships between learning and centrality. While the factors that influence network position are not fully understood, our results suggest that individual differences in learning and becoming successful can play a major role in social centrality, especially when learning from others is advantageous. Copyright © 2018 Elsevier Ltd. All rights reserved.

Alkali, thermo and halo tolerant fungal isolate for the removal of textile dyes.

PubMed

Kaushik, Prachi; Malik, Anushree

2010-11-01

In the present study potential of a fungal isolate Aspergillus lentulusFJ172995, was investigated for the removal of textile dyes. The removal percentages of dyes such as Acid Navy Blue, Orange-HF, Fast Red A, Acid Sulphone Blue and Acid Magenta were determined as 99.43, 98.82, 98.75, 97.67 and 69.98, respectively. None of the dyes inhibited the growth of A. lentulus. Detailed studies on growth kinetics, mechanism of dye removal and effect of different parameters on dye removal were conducted using Acid Navy Blue dye. It was observed that A. lentulus could completely remove Acid Navy Blue even at high initial dye concentrations, up to 900 mg/L. Highest uptake capacity of 212.92 mg/g was observed at an initial dye concentration of 900 mg/L. Dye removing efficiency was not altered with the variation of pH; and biomass production as well as dye removal was favored at higher temperatures. Dye removal was also efficient even at high salt concentration. Through growth kinetics studies it was observed that the initial exponential growth phase coincided with the phase of maximal dye removal. Microscopic studies suggest that bioaccumulation along with biosorption is the principle mechanism involved in dye removal by A. lentulus. Thus, it is concluded that being alkali, thermo and halo tolerant, A. lentulus isolate has a great potential to be utilized for the treatment of dye bearing effluents which are usually alkaline, hot and saline. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Age at first use and later substance use disorder: Shared genetic and environmental pathways for nicotine, alcohol, and cannabis.

PubMed

Richmond-Rakerd, Leah S; Slutske, Wendy S; Lynskey, Michael T; Agrawal, Arpana; Madden, Pamela A F; Bucholz, Kathleen K; Heath, Andrew C; Statham, Dixie J; Martin, Nicholas G

2016-10-01

Behavioral genetic studies have provided insights into why early substance use initiation is associated with increased risk for disorder. Few genetically informative studies, however, have operationalized initiation as the timing of first use and simultaneously modeled the timing of initiation and problematic use of multiple substances. Such research can help capture the risk associated with early initiation and determine the extent to which genetic and environmental risk generalizes across substances. This study utilized a behavior genetic approach to examine the relation between the age of substance use initiation and symptoms of substance use disorder. Participants were 7,285 monozygotic and dizygotic twins (40% male, mean age at interview = 30.6 years) from the Australian Twin Registry who reported on their ages of tobacco, alcohol, and cannabis initiation and symptoms of Diagnostic and Statistical Manual of Mental Disorders (4th ed., DSM-IV) nicotine dependence, alcohol use disorder, and cannabis use disorder. Biometric modeling was conducted to (a) determine the structure of genetic and environmental influences on initiation and disorder and (b) examine their genetic and environmental overlap. The latent structure of initiation differed across men and women. The familial covariance between initiation and disorder was genetic among men and genetic and environmental among women, suggesting that the relation between first substance use and disorder is partly explained by a shared liability. After accounting for familial overlap, significant unique environmental correlations were observed, indicating that the age of initiation of multiple drugs may directly increase risk for substance-related problems. Results support the utility of conceptualizing initiation in terms of age and of adopting a multivariate approach. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Risk of thromboembolism in women taking ethinylestradiol/drospirenone and other oral contraceptives.

PubMed

Seeger, John D; Loughlin, Jeanne; Eng, P Mona; Clifford, C Robin; Cutone, Jennifer; Walker, Alexander M

2007-09-01

The oral contraceptive ethinylestradiol 0.03 mg/drospirenone 3 mg contains a progestin component that differs from other oral contraceptives. Case reports and prescription event monitoring suggested that ethinylestradiol/drospirenone might be associated with an elevated risk of thromboembolism. We sought to estimate the association between ethinylestradiol/drospirenone and risk of thromboembolism relative to the association among other oral contraceptives. We identified ethinylestradiol/drospirenone initiators and a twofold larger group of other oral contraceptive initiators between June 2001 and June 2004 within a U.S. health insurer database. The comparison group was selected to have demographic and health care characteristics preceding oral contraceptive initiation that were similar to ethinylestradiol/drospirenone initiators. Thromboembolism during the follow-up of the cohorts was identified through claims for medical services, and only medical record-confirmed cases were included in analyses. The primary (as-matched) analysis used proportional hazards regression, whereas a secondary (as-treated) analysis accounted for changes in oral contraceptives during follow-up using Poisson regression. The 22,429 ethinylestradiol/drospirenone initiators and 44,858 other oral contraceptive initiators were followed for an average of 7.6 months, and there were 18 cases of thromboembolism in ethinylestradiol/drospirenone initiators and 39 in the comparators (rate ratio 0.9, 95% confidence interval 0.5-1.6). More than 9,000 women would need to be prescribed oral contraceptives to observe a difference of one case of thromboembolism. Results of the as-treated analysis were similar to those of the as-matched analysis. Ethinylestradiol/drospirenone initiators and initiators of other oral contraceptives are similarly likely to experience thromboembolism. II.

Erosion of volcanic ocean islands: insights from modeling, topographic analyses, and cosmogenic exposure dating

NASA Astrophysics Data System (ADS)

Huppert, K.; Perron, J. T.; Ferrier, K.; Mukhopadhyay, S.; Rosener, M.; Douglas, M.

2016-12-01

With homogeneous bedrock, dramatic rainfall gradients, paleoshorelines, and datable remnant topography, volcanic ocean islands provide an exceptional natural experiment in landscape evolution. Analyses traversing gradients in island climate and bedrock age have the potential to advance our understanding of landscape evolution in a diverse range of continental settings. However, as small, conical, dominantly subsiding, and initially highly permeable landmasses, islands are unique, and it remains unclear how these properties influence their erosional history. We use a landscape evolution model and observations from the Hawaiian island of Kaua'i and other islands to characterize the topographic evolution of volcanic ocean islands. We present new measurements of helium-3 concentrations in detrital olivine from 20 rivers on Kaua'i. These measurements indicate that minimum erosion rates over the past 3 to 48 kyr are on average 2.6 times faster than erosion rates averaged over the past 3.9 to 4.4 Myr estimated from the volume of river canyons. This apparent acceleration of erosion rates on Kaua'i is consistent with observations on other islands; erosion rates estimated from the volume of river canyons on 31 islands worldwide, combined with observations of minimal incision on young island volcanoes, suggest a progressive increase in erosion rates over the first few million years of island landscape development. Using a landscape evolution model, we perform a set of experiments to quantify the contribution of subsidence, climate change, and initial geometry to changes in island erosion rates through time. We base these experiments on the evolution of Kaua'i, and we use measured erosion rates and the observed topography to calibrate the model. We find that progressive steepening of island topography by canyon incision drives an acceleration of erosion rates over time. Increases in mean channel and hillslope gradient with island age in the global compilation suggest this may be a general trend in the topographic evolution of volcanic ocean islands.

Lifelong alpha-tocopherol supplementation increases the median life span of C57BL/6 mice in the cold but has only minor effects on oxidative damage.

PubMed

Selman, Colin; McLaren, Jane S; Mayer, Claus; Duncan, Jackie S; Collins, Andrew R; Duthie, Garry G; Redman, Paula; Speakman, John R

2008-02-01

The effects of dietary antioxidant supplementation on oxidative stress and life span are confused. We maintained C57BL/6 mice at 7 +/- 2 degrees C and supplemented their diet with alpha-tocopherol from 4 months of age. Supplementation significantly increased (p = 0.042) median life span by 15% (785 days, n = 44) relative to unsupplemented controls (682 days, n = 43) and also increased maximum life span (oldest 10%, p = 0.028). No sex or sex by treatment interaction effects were observed on life span, with treatment having no effect on resting or daily metabolic rate. Lymphocyte and hepatocyte oxidative DNA damage and hepatic lipid peroxidation were unaffected by supplementation, but hepatic oxidative DNA damage increased with age. Using a cDNA macroarray, genes associated with xenobiotic metabolism were significantly upregulated in the livers of female mice at 6 months of age (2 months supplementation). At 22 months of age (18 months supplementation) this response had largely abated, but various genes linked to the p21 signaling pathway were upregulated at this time. We suggest that alpha-tocopherol may initially be metabolized as a xenobiotic, potentially explaining why previous studies observe a life span extension generally when lifelong supplementation is initiated early in life. The absence of any significant effect on oxidative damage suggests that the life span extension observed was not mediated via any antioxidant properties of alpha-tocopherol. We propose that the life span extension observed following alpha-tocopherol supplementation may be mediated via upregulation of cytochrome p450 genes after 2 months of supplementation and/or upregulation of p21 signaling genes after 18 months of supplementation. However, these signaling pathways now require further investigation to establish their exact role in life span extension following alpha-tocopherol supplementation.

Anomalous Ion Heating, Intrinsic and Induced Rotation in the Pegasus Toroidal Experiment

NASA Astrophysics Data System (ADS)

Burke, M. G.; Barr, J. L.; Bongard, M. W.; Fonck, R. J.; Hinson, E. T.; Perry, J. M.; Redd, A. J.; Thome, K. E.

2014-10-01

Pegasus plasmas are initiated through either standard, MHD stable, inductive current drive or non-solenoidal local helicity injection (LHI) current drive with strong reconnection activity, providing a rich environment to study ion dynamics. During LHI discharges, a large amount of anomalous impurity ion heating has been observed, with Ti ~ 800 eV but Te < 100 eV. The ion heating is hypothesized to be a result of large-scale magnetic reconnection activity, as the amount of heating scales with increasing fluctuation amplitude of the dominant, edge localized, n = 1 MHD mode. Chordal Ti spatial profiles indicate centrally peaked temperatures, suggesting a region of good confinement near the plasma core surrounded by a stochastic region. LHI plasmas are observed to rotate, perhaps due to an inward radial current generated by the stochastization of the plasma edge by the injected current streams. H-mode plasmas are initiated using a combination of high-field side fueling and Ohmic current drive. This regime shows a significant increase in rotation shear compared to L-mode plasmas. In addition, these plasmas have been observed to rotate in the counter-Ip direction without any external momentum sources. The intrinsic rotation direction is consistent with predictions from the saturated Ohmic confinement regime. Work supported by US DOE Grant DE-FG02-96ER54375.

Transition from Collisional to Collisionless Regimes in Interpenetrating Plasma Flows on the National Ignition Facility

DOE PAGES

Ross, J. S.; Higginson, D. P.; Ryutov, D.; ...

2017-05-05

A study of the transition from collisional to collisionless plasma flows has been carried out at the National Ignition Facility using high Mach number (M > 4) counterstreaming plasmas. In these experiments, CD-CD and CD-CH planar foils separated by 6–10 mm are irradiated with laser energies of 250 kJ per foil, generating ~1000 km/s plasma flows. Varying the foil separation distance scales the ion density and average bulk velocity and, therefore, the ion-ion Coulomb mean free path, at the interaction region at the midplane. The characteristics of the flow interaction have been inferred from the neutrons and protons generated bymore » deuteron-deuteron interactions and by x-ray emission from the hot, interpenetrating, and interacting plasmas. A localized burst of neutrons and bright x-ray emission near the midpoint of the counterstreaming flows was observed, suggesting strong heating and the initial stages of shock formation. As the separation of the CD-CH foils increases we observe enhanced neutron production compared to particle-in-cell simulations that include Coulomb collisions, but do not include collective collisionless plasma instabilities. Here, the observed plasma heating and enhanced neutron production is consistent with the initial stages of collisionless shock formation, mediated by the Weibel filamentation instability.« less

AGCM Biases in Evaporation Regime: Impacts on Soil Moisture Memory and Land-Atmosphere Feedback

NASA Technical Reports Server (NTRS)

Mahanama, Sarith P. P.; Koster, Randal D.

2005-01-01

Because precipitation and net radiation in an atmospheric general circulation model (AGCM) are typically biased relative to observations, the simulated evaporative regime of a region may be biased, with consequent negative effects on the AGCM s ability to translate an initialized soil moisture anomaly into an improved seasonal prediction. These potential problems are investigated through extensive offline analyses with the Mosaic land surface model (LSM). We first forced the LSM globally with a 15-year observations-based dataset. We then repeated the simulation after imposing a representative set of GCM climate biases onto the forcings - the observational forcings were scaled so that their mean seasonal cycles matched those simulated by the NSIPP-1 (NASA Global Modeling and Assimilation Office) AGCM over the same period-The AGCM s climate biases do indeed lead to significant biases in evaporative regime in certain regions, with the expected impacts on soil moisture memory timescales. Furthermore, the offline simulations suggest that the biased forcing in the AGCM should contribute to overestimated feedback in certain parts of North America - parts already identified in previous studies as having excessive feedback. The present study thus supports the notion that the reduction of climate biases in the AGCM will lead to more appropriate translations of soil moisture initialization into seasonal prediction skill.

Noninvasive in vivo optical coherence tomography tracking of chronic otitis media in pediatric subjects after surgical intervention

NASA Astrophysics Data System (ADS)

Monroy, Guillermo L.; Pande, Paritosh; Nolan, Ryan M.; Shelton, Ryan L.; Porter, Ryan G.; Novak, Michael A.; Spillman, Darold R.; Chaney, Eric J.; McCormick, Daniel T.; Boppart, Stephen A.

2017-12-01

In an institutional review board-approved study, 25 pediatric subjects diagnosed with chronic or recurrent otitis media were observed over a period of six months with optical coherence tomography (OCT). Subjects were followed throughout their treatment at the initial patient evaluation and preoperative consultation, surgery (intraoperative imaging), and postoperative follow-up, followed by an additional six months of records-based observation. At each time point, the tympanic membrane (at the light reflex region) and directly adjacent middle-ear cavity were observed in vivo with a handheld OCT probe and portable system. Imaging results were compared with clinical outcomes to correlate the clearance of symptoms in relation to changes in the image-based features of infection. OCT images of most all participants showed the presence of additional infection-related biofilm structures during their initial consultation visit and similarly for subjects imaged intraoperatively before myringotomy. Subjects with successful treatment (no recurrence of infectious symptoms) had no additional structures visible in OCT images during the postoperative visit. OCT image findings suggest surgical intervention consisting of myringotomy and tympanostomy tube placement provides a means to clear the middle ear of infection-related components, including middle-ear fluid and biofilms. Furthermore, OCT was demonstrated as a rapid diagnostic tool to prospectively monitor patients in both outpatient and surgical settings.

Transition from Collisional to Collisionless Regimes in Interpenetrating Plasma Flows on the National Ignition Facility.

PubMed

Ross, J S; Higginson, D P; Ryutov, D; Fiuza, F; Hatarik, R; Huntington, C M; Kalantar, D H; Link, A; Pollock, B B; Remington, B A; Rinderknecht, H G; Swadling, G F; Turnbull, D P; Weber, S; Wilks, S; Froula, D H; Rosenberg, M J; Morita, T; Sakawa, Y; Takabe, H; Drake, R P; Kuranz, C; Gregori, G; Meinecke, J; Levy, M C; Koenig, M; Spitkovsky, A; Petrasso, R D; Li, C K; Sio, H; Lahmann, B; Zylstra, A B; Park, H-S

2017-05-05

A study of the transition from collisional to collisionless plasma flows has been carried out at the National Ignition Facility using high Mach number (M>4) counterstreaming plasmas. In these experiments, CD-CD and CD-CH planar foils separated by 6-10 mm are irradiated with laser energies of 250 kJ per foil, generating ∼1000  km/s plasma flows. Varying the foil separation distance scales the ion density and average bulk velocity and, therefore, the ion-ion Coulomb mean free path, at the interaction region at the midplane. The characteristics of the flow interaction have been inferred from the neutrons and protons generated by deuteron-deuteron interactions and by x-ray emission from the hot, interpenetrating, and interacting plasmas. A localized burst of neutrons and bright x-ray emission near the midpoint of the counterstreaming flows was observed, suggesting strong heating and the initial stages of shock formation. As the separation of the CD-CH foils increases we observe enhanced neutron production compared to particle-in-cell simulations that include Coulomb collisions, but do not include collective collisionless plasma instabilities. The observed plasma heating and enhanced neutron production is consistent with the initial stages of collisionless shock formation, mediated by the Weibel filamentation instability.

VARIABLE AND EXTREME IRRADIATION CONDITIONS IN THE EARLY SOLAR SYSTEM INFERRED FROM THE INITIAL ABUNDANCE OF {sup 10}Be IN ISHEYEVO CAIs

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

Gounelle, Matthieu; Chaussidon, Marc; Rollion-Bard, Claire, E-mail: gounelle@mnhn.fr

2013-02-01

A search for short-lived {sup 10}Be in 21 calcium-aluminum-rich inclusions (CAIs) from Isheyevo, a rare CB/CH chondrite, showed that only 5 CAIs had {sup 10}B/{sup 11}B ratios higher than chondritic correlating with the elemental ratio {sup 9}Be/{sup 11}B, suggestive of in situ decay of this key short-lived radionuclide. The initial ({sup 10}Be/{sup 9}Be){sub 0} ratios vary between {approx}10{sup -3} and {approx}10{sup -2} for CAI 411. The initial ratio of CAI 411 is one order of magnitude higher than the highest ratio found in CV3 CAIs, suggesting that the more likely origin of CAI 411 {sup 10}Be is early solar systemmore » irradiation. The low ({sup 26}Al/{sup 27}Al){sub 0} [{<=} 8.9 Multiplication-Sign 10{sup -7}] with which CAI 411 formed indicates that it was exposed to gradual flares with a proton fluence of a few 10{sup 19} protons cm{sup -2}, during the earliest phases of the solar system, possibly the infrared class 0. The irradiation conditions for other CAIs are less well constrained, with calculated fluences ranging between a few 10{sup 19} and 10{sup 20} protons cm{sup -2}. The variable and extreme value of the initial {sup 10}Be/{sup 9}Be ratios in carbonaceous chondrite CAIs is the reflection of the variable and extreme magnetic activity in young stars observed in the X-ray domain.« less

Decadal trends in marine reserves reveal differential rates of change in direct and indirect effects

USGS Publications Warehouse

Babcock, R.C.; Shears, N.T.; Alcala, A.C.; Barrett, N.S.; Edgar, G.J.; Lafferty, K.D.; McClanahan, T.R.; Russ, G.R.

2010-01-01

Decadal-scale observations of marine reserves suggest that indirect effects on taxa that occur through cascading trophic interactions take longer to develop than direct effects on target species. Combining and analyzing a unique set of long-term time series of ecologic data in and out of fisheries closures from disparate regions, we found that the time to initial detection of direct effects on target species (+ or -SE) was 5.13 + or - 1.9 years, whereas initial detection of indirect effects on other taxa, which were often trait mediated, took significantly longer (13.1 + or - 2.0 years). Most target species showed initial direct effects, but their trajectories over time were highly variable. Many target species continued to increase, some leveled off, and others decreased. Decreases were due to natural fluctuations, fishing impacts from outside reserves, or indirect effects from target species at higher trophic levels. The average duration of stable periods for direct effects was 6.2 + or - 1.2 years, even in studies of more than 15 years. For indirect effects, stable periods averaged 9.1 + or - 1.6 years, although this was not significantly different from direct effects. Populations of directly targeted species were more stable in reserves than in fished areas, suggesting increased ecologic resilience. This is an important benefit of marine reserves with respect to their function as a tool for conservation and restoration.

Ab initio metadynamics simulations of oxygen/ligand interactions in organoaluminum clusters

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

Alnemrat, Sufian; Hooper, Joseph P., E-mail: jphooper@nps.edu

2014-10-14

Car-Parrinello molecular dynamics combined with a metadynamics algorithm is used to study the initial interaction of O{sub 2} with the low-valence organoaluminum clusters Al{sub 4}Cp{sub 4} (Cp=C{sub 5}H{sub 5}) and Al{sub 4}Cp{sub 4}{sup *} (Cp{sup *}=C{sub 5}[CH{sub 3}]{sub 5}). Prior to reaction with the aluminum core, simulations suggest that the oxygen undergoes a hindered crossing of the steric barrier presented by the outer ligand monolayer. A combination of two collective variables based on aluminum/oxygen distance and lateral oxygen displacement was found to produce distinct reactant, product, and transition states for this process. In the methylated cluster with Cp{sup *} ligands,more » a broad transition state of 45 kJ/mol was observed due to direct steric interactions with the ligand groups and considerable oxygen reorientation. In the non-methylated cluster the ligands distort away from the oxidizer, resulting in a barrier of roughly 34 kJ/mol with minimal O{sub 2} reorientation. A study of the oxygen/cluster system fixed in a triplet multiplicity suggests that the spin state does not affect the initial steric interaction with the ligands. The metadynamics approach appears to be a promising means of analyzing the initial steps of such oxidation reactions for ligand-protected clusters.« less

Cytocompatibility and Mechanical Properties of Short Phosphate Glass Fibre Reinforced Polylactic Acid (PLA) Composites: Effect of Coupling Agent Mediated Interface

PubMed Central

Hasan, Muhammad Sami; Ahmed, Ifty; Parsons, Andrew; Walker, Gavin; Scotchford, Colin

2012-01-01

In this study three chemical agents Amino-propyl-triethoxy-silane (APS), sorbitol ended PLA oligomer (SPLA) and Hexamethylene diisocyanate (HDI) were identified to be used as coupling agents to react with the phosphate glass fibre (PGF) reinforcement and the polylactic acid (PLA) polymer matrix of the composite. Composites were prepared with short chopped strand fibres (l = 20 mm, ϕ = 20 µm) in a random arrangement within PLA matrix. Improved, initial composite flexural strength (~20 MPa) was observed for APS treated fibres, which was suggested to be due to enhanced bonding between the fibres and polymer matrix. Both APS and HDI treated fibres were suggested to be covalently linked with the PLA matrix. The hydrophobicity induced by these coupling agents (HDI, APS) helped to resist hydrolysis of the interface and thus retained their mechanical properties for an extended period of time as compared to non-treated control. Approximately 70% of initial strength and 65% of initial modulus was retained by HDI treated fibre composites in contrast to the control, where only ~50% of strength and modulus was retained after 28 days of immersion in PBS at 37 °C. All coupling agent treated and control composites demonstrated good cytocompatibility which was comparable to the tissue culture polystyrene (TCP) control, supporting the use of these materials as coupling agent’s within medical implant devices. PMID:24955744

Decadal trends in marine reserves reveal differential rates of change in direct and indirect effects.

PubMed

Babcock, R C; Shears, N T; Alcala, A C; Barrett, N S; Edgar, G J; Lafferty, K D; McClanahan, T R; Russ, G R

2010-10-26

Decadal-scale observations of marine reserves suggest that indirect effects on taxa that occur through cascading trophic interactions take longer to develop than direct effects on target species. Combining and analyzing a unique set of long-term time series of ecologic data in and out of fisheries closures from disparate regions, we found that the time to initial detection of direct effects on target species (±SE) was 5.13 ± 1.9 years, whereas initial detection of indirect effects on other taxa, which were often trait mediated, took significantly longer (13.1 ± 2.0 years). Most target species showed initial direct effects, but their trajectories over time were highly variable. Many target species continued to increase, some leveled off, and others decreased. Decreases were due to natural fluctuations, fishing impacts from outside reserves, or indirect effects from target species at higher trophic levels. The average duration of stable periods for direct effects was 6.2 ± 1.2 years, even in studies of more than 15 years. For indirect effects, stable periods averaged 9.1 ± 1.6 years, although this was not significantly different from direct effects. Populations of directly targeted species were more stable in reserves than in fished areas, suggesting increased ecologic resilience. This is an important benefit of marine reserves with respect to their function as a tool for conservation and restoration.

Fault geometry and mechanics of marly carbonate multilayers: An integrated field and laboratory study from the Northern Apennines, Italy

NASA Astrophysics Data System (ADS)

Giorgetti, C.; Collettini, C.; Scuderi, M. M.; Barchi, M. R.; Tesei, T.

2016-12-01

Sealing layers are often represented by sedimentary sequences characterized by alternating strong and weak lithologies. When involved in faulting processes, these mechanically heterogeneous multilayers develop complex fault geometries. Here we investigate fault initiation and evolution within a mechanical multilayer by integrating field observations and rock deformation experiments. Faults initiate with a staircase trajectory that partially reflects the mechanical properties of the involved lithologies, as suggested by our deformation experiments. However, some faults initiating at low angles in calcite-rich layers (θi = 5°-20°) and at high angles in clay-rich layers (θi = 45°-86°) indicate the important role of structural inheritance at the onset of faulting. With increasing displacement, faults develop well-organized fault cores characterized by a marly, foliated matrix embedding fragments of limestone. The angles of fault reactivation, which concentrate between 30° and 60°, are consistent with the low friction coefficient measured during our experiments on marls (μs = 0.39), indicating that clay minerals exert a main control on fault mechanics. Moreover, our integrated analysis suggests that fracturing and faulting are the main mechanisms allowing fluid circulation within the low-permeability multilayer, and that its sealing integrity can be compromised only by the activity of larger faults cutting across its entire thickness.

Simulating the Initial Dynamics of the 18 May 1980 Mount St.Helens Blast

NASA Astrophysics Data System (ADS)

Esposti Ongaro, T.; Widiwijayanti, C.; Voight, B.; Clarke, A. B.; Neri, A.

2008-12-01

The initial stage of the 18 May 1980 blast at Mount St. Helens (MSH) has been simulated numerically by the 2D/3D multiphase multiparticle flow model PDAC (Neri et al., J. Geophys. Res. 108 (B4), 2003; Esposti Ongaro et al., Parallel Computing 33, 2007), to provide further insight into the fluid dynamics of this phenomenon. Initial source conditions, including the gas content, the total mass of juvenile and entrained rocks, the temperature, grain size distribution and pre-eruption pressure distribution in the lava dome have been parameterized accordingly to field evidence, available geological constraints and simple theoretical models. Simulation results suggest that the MSH blast can be characterized as an expansion phase (burst), lasting about ten seconds, followed by collapse and pyroclastic density current (PDC) phases. In the burst phase the pressure forces dominate and the flow can locally reach supersonic velocities and generate pressure waves that can be tracked by the numerical model. In the collapse and PDC phases the flow is dominantly gravity-driven and the dynamics are strongly controlled by the source geometry, vertical stratification within the flow and by the 3D topography. The simulations suggest that the severe damage observed at MSH can be explained by high dynamic pressures in gravity currents, and the rapid decrease of dynamic pressure from proximal to distal areas (and related parameters of PDC velocity and density) was largely related to rugged topography beyond the North Fork Toutle River valley. Although the source models investigated thus far represent a simplification of the actual geometry and complex sequence of initial events, we show that the explosion mechanisms are significantly robust over a wide range of initial conditions. Simulation results for MSH are also consistent with those obtained in a previous application of a similar model to the 1997 Boxing Day blast pulses at Soufriere Hills volcano (Montserrat, West Indies) (Esposti Ongaro et al., J. Geophys. Res. 113 (B03211), 2008), which were at least ten times smaller, thus suggesting that the simulated mechanisms are largely independent of eruption scale.

Constraints on core-collapse supernova progenitors from explosion site integral field spectroscopy

NASA Astrophysics Data System (ADS)

Kuncarayakti, H.; Anderson, J. P.; Galbany, L.; Maeda, K.; Hamuy, M.; Aldering, G.; Arimoto, N.; Doi, M.; Morokuma, T.; Usuda, T.

2018-05-01

Context. Observationally, supernovae (SNe) are divided into subclasses according to their distinct characteristics. This diversity naturally reflects the diversity in the progenitor stars. It is not entirely clear, however, how different evolutionary paths leading massive stars to become an SN are governed by fundamental parameters such as progenitor initial mass and metallicity. Aims: This paper places constraints on progenitor initial mass and metallicity in distinct core-collapse SN subclasses through a study of the parent stellar populations at the explosion sites. Methods: Integral field spectroscopy (IFS) of 83 nearby SN explosion sites with a median distance of 18 Mpc has been collected and analysed, enabling detection and spectral extraction of the parent stellar population of SN progenitors. From the parent stellar population spectrum, the initial mass and metallicity of the coeval progenitor are derived by means of comparison to simple stellar population models and strong-line methods. Additionally, near-infrared IFS was employed to characterise the star formation history at the explosion sites. Results: No significant metallicity differences are observed among distinct SN types. The typical progenitor mass is found to be highest for SN type Ic, followed by type Ib, then types IIb and II. Type IIn is the least associated with young stellar populations and thus massive progenitors. However, statistically significant differences in progenitor initial mass are observed only when comparing SNe IIn with other subclasses. Stripped-envelope SN progenitors with initial mass estimates lower than 25 M⊙ are found; they are thought to be the result of binary progenitors. Confirming previous studies, these results support the notion that core-collapse SN progenitors cannot arise from single-star channels only, and both single and binary channels are at play in the production of core-collapse SNe. Near-infrared IFS suggests that multiple stellar populations with different ages may be present in some of the SN sites. As a consequence, there could be a non-negligible amount of contamination from old populations, and therefore the individual age estimates are effectively lower limits. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programmes 089.D-0367, 091.D-0482, 093.D-0318, 094.D-0290, and 095.D-0172

Reactive flow models of the Anarraaq Zn-Pb-Ag deposit, Red Dog district, Alaska

USGS Publications Warehouse

Schardt, C.; Garven, G.; Kelley, K.D.; Leach, D.L.

2008-01-01

The Red Dog ore deposit district in the Brooks Range of northern Alaska is host to several high-grade, shale-hosted Zn + Pb deposits. Due to the complex history and deformation of these ore deposits, the geological and hydrological conditions at the time of formation are poorly understood. Using geological observations and fluid inclusion data as constraints, numerical heat and fluid flow simulations of the Anarraaq ore deposit environment and coupled reactive flow simulations of a section of the ore body were conducted to gain more insight into the conditions of ore body formation. Results suggest that the ore body and associated base metal zonation may have formed by the mixing of oxidized, saline, metal-bearing hydrothermal fluids (<200??C) with reducing, HS-rich pore fluids within radiolarite-rich host rocks. Sphalerite and galena concentrations and base metal sulfide distribution are primarily controlled by the nature of the pore fluids, i.e., the extent and duration of the HS- source. Forward modeling results also predict the distribution of pyrite and quartz in agreement with field observations and indicate a reaction front moving from the initial mixing interface into the radiolarite rocks. Heuristic mass calculations suggest that ore grades and base metal accumulation comparable to those found in the field (18% Zn, 5% Pb) are predicted to be reached after about 0.3 My for initial conditions (30 ppm Zn, 3 ppm Pb; 20% deposition efficiency). ?? Springer-Verlag 2008.

Deriving Childhood Temperament Measures from Emotion-eliciting Behavioral Episodes: Scale Construction and Initial Validation

PubMed Central

Gagne, Jeffrey R.; Van Hulle, Carol A.; Aksan, Nazan; Essex, Marilyn J.; Goldsmith, H. Hill

2010-01-01

The authors describe the development and initial validation of a home-based version of the Laboratory Temperament Assessment Battery (Lab-TAB), which was designed to assess childhood temperament using a comprehensive series of emotion-eliciting behavioral episodes. This paper provides researchers with general guidelines for assessing specific behaviors using the Lab-TAB and for forming behavioral composites that correspond to commonly researched temperament dimensions. We used mother ratings and independent post-visit observer ratings to provide validity evidence in a community sample of 4.5 year-old children. 12 Lab-TAB behavioral episodes were employed, yielding 24 within-episode temperament components that collapsed into 9 higher-level composites (Anger, Sadness, Fear, Shyness, Positive Expression, Approach, Active Engagement, Persistence, and Inhibitory Control). These dimensions of temperament are similar to those found in questionnaire-based assessments. Correlations among the 9 composites were low to moderate, suggesting relative independence. As expected, agreement between Lab-TAB measures and post-visit observer ratings was stronger than agreement between the Lab-TAB and mother questionnaire. However, for Active Engagement and Shyness, mother ratings did predict child behavior in the Lab-TAB quite well. Findings demonstrate the feasibility of emotion-eliciting temperament assessment methodologies, suggest appropriate methods for data aggregation into trait-level constructs, and set some expectations for associations between Lab-TAB dimensions and the degree of cross-method convergence between the Lab-TAB and other commonly used temperament assessments. PMID:21480723

Relatively high motivation for context-evoked reward produces the magnitude effect in rats.

PubMed

Yuki, Shoko; Okanoya, Kazuo

2014-09-01

Using a concurrent-chain schedule, we demonstrated the effect of absolute reinforcement (i.e., the magnitude effect) on choice behavior in rats. In general, animals' simultaneous choices conform to a relative reinforcement ratio between alternatives. However, studies in pigeons and rats have found that on a concurrent-chain schedule, the overall reinforcement ratio, or absolute amount, also influences choice. The effect of reinforcement amount has also been studied in inter-temporal choice situations, and this effect has been referred to as the magnitude effect. The magnitude effect has been observed in humans under various conditions, but little research has assessed it in animals (e.g., pigeons and rats). The present study confirmed the effect of reinforcement amount in rats during simultaneous and inter-temporal choice situations. We used a concurrent-chain procedure to examine the cause of the magnitude effect during inter-temporal choice. Our results suggest that rats can use differences in reinforcement amount as a contextual cue during choice, and the direction of the magnitude effect in rats might be similar to humans when using the present procedure. Furthermore, our results indicate that the magnitude effect was caused by the initial-link effect when the reinforcement amount was relatively small, while a loss aversion tendency was observed when the reinforcement amount changed within a session. The emergence of the initial-link effect and loss aversion suggests that rats make choices through cognitive processes predicted by prospect theory. Copyright © 2014 Elsevier B.V. All rights reserved.

Functional silencing is initiated and maintained in immature anti-insulin B cells.

PubMed

Henry, Rachel A; Acevedo-Suárez, Carlos A; Thomas, James W

2009-03-15

Mechanisms of B cell tolerance act during development in the bone marrow and periphery to eliminate or restrict autoreactive clones to prevent autoimmune disease. B cells in the spleens of mice that harbor anti-insulin BCR transgenes (125Tg) are maintained in a functionally silenced or anergic state by endogenous hormone, but it is not clear when and where anergy is induced. An in vitro bone marrow culture system was therefore used to probe whether small protein hormones, a critical class of autoantigens, could interact with the BCR to induce anergy early during B cell development. Upon exposure to insulin, anti-insulin (125Tg) immature B cells show similar hallmarks of anergy as those observed in mature splenic B cells. These include BCR down-regulation, impaired proliferative responses to anti-CD40, and diminished calcium mobilization upon stimulation with BCR-dependent and independent stimuli. Inhibition of calcineurin also results in reduced immature B cell proliferation in a similar manner, suggesting a potential mechanism through which reduced intracellular calcium mobilization may be altering cellular proliferation. Signs of impairment appear after short-term exposure to insulin, which are reversible upon Ag withdrawal. This suggests that a high degree of functional plasticity is maintained at this stage and that constant Ag engagement is required to maintain functional inactivation. These findings indicate that tolerance observed in mature, splenic 125Tg B cells is initiated by insulin in the developing B cell compartment and thus highlight an important therapeutic window for the prevention of insulin autoimmunity.

A single dose of inactivated hepatitis A vaccine promotes HAV-specific memory cellular response similar to that induced by a natural infection.

PubMed

Melgaço, Juliana Gil; Morgado, Lucas Nóbrega; Santiago, Marta Almeida; Oliveira, Jaqueline Mendes de; Lewis-Ximenez, Lia Laura; Hasselmann, Bárbara; Cruz, Oswaldo Gonçalves; Pinto, Marcelo Alves; Vitral, Claudia Lamarca

2015-07-31

Based on current studies on the effects of single dose vaccines on antibody production, Latin American countries have adopted a single dose vaccine program. However, no data are available on the activation of cellular response to a single dose of hepatitis A. Our study investigated the functional reactivity of the memory cell phenotype after hepatitis A virus (HAV) stimulation through administration of the first or second dose of HAV vaccine and compared the response to that of a baseline group to an initial natural infection. Proliferation assays showed that the first vaccine dose induced HAV-specific cellular response; this response was similar to that induced by a second dose or an initial natural infection. Thus, from the first dose to the second dose, increase in the frequencies of classical memory B cells, TCD8 cells, and central memory TCD4 and TCD8 cells were observed. Regarding cytokine production, increased IL-6, IL-10, TNF, and IFNγ levels were observed after vaccination. Our findings suggest that a single dose of HAV vaccine promotes HAV-specific memory cell response similar to that induced by a natural infection. The HAV-specific T cell immunity induced by primary vaccination persisted independently of the protective plasma antibody level. In addition, our results suggest that a single dose immunization system could serve as an alternative strategy for the prevention of hepatitis A in developing countries. Copyright © 2015 Elsevier Ltd. All rights reserved.

3D numerical simulations of multiphase continental rifting

NASA Astrophysics Data System (ADS)

Naliboff, J.; Glerum, A.; Brune, S.

2017-12-01

Observations of rifted margin architecture suggest continental breakup occurs through multiple phases of extension with distinct styles of deformation. The initial rifting stages are often characterized by slow extension rates and distributed normal faulting in the upper crust decoupled from deformation in the lower crust and mantle lithosphere. Further rifting marks a transition to higher extension rates and coupling between the crust and mantle lithosphere, with deformation typically focused along large-scale detachment faults. Significantly, recent detailed reconstructions and high-resolution 2D numerical simulations suggest that rather than remaining focused on a single long-lived detachment fault, deformation in this phase may progress toward lithospheric breakup through a complex process of fault interaction and development. The numerical simulations also suggest that an initial phase of distributed normal faulting can play a key role in the development of these complex fault networks and the resulting finite deformation patterns. Motivated by these findings, we will present 3D numerical simulations of continental rifting that examine the role of temporal increases in extension velocity on rifted margin structure. The numerical simulations are developed with the massively parallel finite-element code ASPECT. While originally designed to model mantle convection using advanced solvers and adaptive mesh refinement techniques, ASPECT has been extended to model visco-plastic deformation that combines a Drucker Prager yield criterion with non-linear dislocation and diffusion creep. To promote deformation localization, the internal friction angle and cohesion weaken as a function of accumulated plastic strain. Rather than prescribing a single zone of weakness to initiate deformation, an initial random perturbation of the plastic strain field combined with rapid strain weakening produces distributed normal faulting at relatively slow rates of extension in both 2D and 3D simulations. Our presentation will focus on both the numerical assumptions required to produce these results and variations in 3D rifted margin architecture arising from a transition from slow to rapid rates of extension.

Carcinogen-induced mutations in the mouse c-Ha-ras gene provide evidence of multiple pathways for tumor progression.

PubMed Central

Brown, K; Buchmann, A; Balmain, A

1990-01-01

A number of mouse skin tumors initiated by the carcinogens N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), methylnitrosourea (MNU), 3-methylcholanthrene (MCA), and 7,12-dimethylbenz[a]anthracene (DMBA) have been shown to contain activated Ha-ras genes. In each case, the point mutations responsible for activation have been characterized. Results presented demonstrate the carcinogen-specific nature of these ras mutations. For each initiating agent, a distinct spectrum of mutations is observed. Most importantly, the distribution of ras gene mutations is found to differ between benign papillomas and carcinomas, suggesting that molecular events occurring at the time of initiation influence the probability with which papillomas progress to malignancy. This study provides molecular evidence in support of the existence of subsets of papillomas with differing progression frequencies. Thus, the alkylating agents MNNG and MNU induced exclusively G ---- A transitions at codon 12, with this mutation being found predominantly in papillomas. MCA initiation produced both codon 13 G ---- T and codon 61 A ---- T transversions in papillomas; only the G ---- T mutation, however, was found in carcinomas. These findings provide strong evidence that the mutational activation of Ha-ras occurs as a result of the initiation process and that the nature of the initiating event can affect the probability of progression to malignancy. Images PMID:2105486

Outcome of Early Initiation of Peritoneal Dialysis in Patients with End-Stage Renal Failure

PubMed Central

Oh, Kook-Hwan; Hwang, Young-Hwan; Cho, Jung-Hwa; Kim, Mira; Ju, Kyung Don; Joo, Kwon Wook; Kim, Dong Ki; Kim, Yon Su; Ahn, Curie

2012-01-01

Recent studies reported that early initiation of hemodialysis may increase mortality. However, studies that assessed the influence of early initiation of peritoneal dialysis (PD) yielded controversial results. In the present study, we evaluated the prognosis of early initiation of PD on the various outcomes of end stage renal failure patients by using propensity-score matching methods. Incident PD patients (n = 491) who started PD at SNU Hospital were enrolled. The patients were divided into 'early starters (n = 244)' and 'late starters (n = 247)' on the basis of the estimated glomerular filtration rate (eGFR) at the start of dialysis. The calculated propensity-score was used for one-to-one matching. After propensity-score-based matching (n = 136, for each group), no significant differences were observed in terms of all-cause mortality (P = 0.17), technique failure (P = 0.62), cardiovascular event (P = 0.96) and composite event (P = 0.86) between the early and late starters. Stratification analysis in the propensity-score quartiles (n = 491) exhibited no trend toward better or poorer survival in terms of all-cause mortality. In conclusion, early commencement of PD does not reduce the mortality risk and other outcomes. Although the recent guidelines suggest that initiation of dialysis at higher eGFR, physicians should not determine the time to initiate PD therapy simply rely on the eGFR alone. PMID:22323864

Dynamic patterning by the Drosophila pair-rule network reconciles long-germ and short-germ segmentation

PubMed Central

2017-01-01

Drosophila segmentation is a well-established paradigm for developmental pattern formation. However, the later stages of segment patterning, regulated by the “pair-rule” genes, are still not well understood at the system level. Building on established genetic interactions, I construct a logical model of the Drosophila pair-rule system that takes into account the demonstrated stage-specific architecture of the pair-rule gene network. Simulation of this model can accurately recapitulate the observed spatiotemporal expression of the pair-rule genes, but only when the system is provided with dynamic “gap” inputs. This result suggests that dynamic shifts of pair-rule stripes are essential for segment patterning in the trunk and provides a functional role for observed posterior-to-anterior gap domain shifts that occur during cellularisation. The model also suggests revised patterning mechanisms for the parasegment boundaries and explains the aetiology of the even-skipped null mutant phenotype. Strikingly, a slightly modified version of the model is able to pattern segments in either simultaneous or sequential modes, depending only on initial conditions. This suggests that fundamentally similar mechanisms may underlie segmentation in short-germ and long-germ arthropods. PMID:28953896

The Poleward Boundary Intensification (PBI) of Auroral Emission: Its Dynamics and Associated Field-aligned Current System

NASA Astrophysics Data System (ADS)

Ohtani, S.; Motoba, T.; Gjerloev, J. W.

2016-12-01

The poleward boundary intensification (PBI) of aurora emission is often addressed in terms of distant reconnection. Recently, however, Ohtani and Yoshikawa [2016] proposed that the PBIs, at least at the initial stage of their formation, are actually the effect of ionospheric polarization in the presence of the enhanced convection in the polar cap and conductance gradient at the poleward boundary of the auroral oval. Whereas the ionospheric polarization itself is a transient process, it is known that the PBIs occasionally extend longitudinally suggesting that a 3D current system forms subsequently, which electrodynamically couples the magnetosphere and ionosphere. In the present study we observationally examine the associated field-aligned current (FAC) observed by the SWARM satellites and compare its characteristics with ground all-sky images. It is found that complex signatures of FACs as suggested by magnetic disturbances reflect the spatial structure of aurora (e.g., location and orientation), whereas the overall motion of PBIs is well explained in terms of the background convection suggested by the FAC distribution. We shall discuss the implications of these results for the responsible evolution process of the PBIs.

Regulatory Mechanisms That Prevent Re-initiation of DNA Replication Can Be Locally Modulated at Origins by Nearby Sequence Elements

PubMed Central

Richardson, Christopher D.; Li, Joachim J.

2014-01-01

Eukaryotic cells must inhibit re-initiation of DNA replication at each of the thousands of origins in their genome because re-initiation can generate genomic alterations with extraordinary frequency. To minimize the probability of re-initiation from so many origins, cells use a battery of regulatory mechanisms that reduce the activity of replication initiation proteins. Given the global nature of these mechanisms, it has been presumed that all origins are inhibited identically. However, origins re-initiate with diverse efficiencies when these mechanisms are disabled, and this diversity cannot be explained by differences in the efficiency or timing of origin initiation during normal S phase replication. This observation raises the possibility of an additional layer of replication control that can differentially regulate re-initiation at distinct origins. We have identified novel genetic elements that are necessary for preferential re-initiation of two origins and sufficient to confer preferential re-initiation on heterologous origins when the control of re-initiation is partially deregulated. The elements do not enhance the S phase timing or efficiency of adjacent origins and thus are specifically acting as re-initiation promoters (RIPs). We have mapped the two RIPs to ∼60 bp AT rich sequences that act in a distance- and sequence-dependent manner. During the induction of re-replication, Mcm2-7 reassociates both with origins that preferentially re-initiate and origins that do not, suggesting that the RIP elements can overcome a block to re-initiation imposed after Mcm2-7 associates with origins. Our findings identify a local level of control in the block to re-initiation. This local control creates a complex genomic landscape of re-replication potential that is revealed when global mechanisms preventing re-replication are compromised. Hence, if re-replication does contribute to genomic alterations, as has been speculated for cancer cells, some regions of the genome may be more susceptible to these alterations than others. PMID:24945837

Multiple populations within globular clusters in Early-type galaxies Exploring their effect on stellar initial mass function estimates

NASA Astrophysics Data System (ADS)

Chantereau, W.; Usher, C.; Bastian, N.

2018-05-01

It is now well-established that most (if not all) ancient globular clusters host multiple populations, that are characterised by distinct chemical features such as helium abundance variations along with N-C and Na-O anti-correlations, at fixed [Fe/H]. These very distinct chemical features are similar to what is found in the centres of the massive early-type galaxies and may influence measurements of the global properties of the galaxies. Additionally, recent results have suggested that M/L variations found in the centres of massive early-type galaxies might be due to a bottom-heavy stellar initial mass function. We present an analysis of the effects of globular cluster-like multiple populations on the integrated properties of early-type galaxies. In particular, we focus on spectral features in the integrated optical spectrum and the global mass-to-light ratio that have been used to infer variations in the stellar initial mass function. To achieve this we develop appropriate stellar population synthesis models and take into account, for the first time, an initial-final mass relation which takes into consideration a varying He abundance. We conclude that while the multiple populations may be present in massive early-type galaxies, they are likely not responsible for the observed variations in the mass-to-light ratio and IMF sensitive line strengths. Finally, we estimate the fraction of stars with multiple populations chemistry that come from disrupted globular clusters within massive ellipticals and find that they may explain some of the observed chemical patterns in the centres of these galaxies.

Regulation of anxiety and initiation of sexual behavior by CREB in the nucleus accumbens

PubMed Central

Barrot, Michel; Wallace, Deanna L.; Bolaños, Carlos A.; Graham, Danielle L.; Perrotti, Linda I.; Neve, Rachael L.; Chambliss, Heather; Yin, Jerry C.; Nestler, Eric J.

2005-01-01

Sexual deficits and other behavioral disturbances such as anxiety-like behaviors can be observed in animals that have undergone social isolation, especially in species having important social interactions. Using a model of protracted social isolation in adult rats, we observed increased anxiety-like behavior and deficits in both the latency to initiate sexual behavior and the latency to ejaculate. We show, using transgenic cAMP response element (CRE)-LacZ reporter mice, that protracted social isolation also reduces CRE-dependent transcription within the nucleus accumbens. This decrease in CRE-dependent transcription can be mimicked in nonisolated animals by local viral gene transfer of a dominant negative mutant of CRE-binding protein (CREB). We previously showed that this manipulation increases anxiety-like behavior. We show here that it also impairs initiation of sexual behavior in nonisolated animals, a deficit that can be corrected by anxiolytic drug treatment. This local reduction in CREB activity, however, has no influence on ejaculation parameters. Reciprocally, we used the viral transgenic approach to overexpress CREB in the nucleus accumbens of isolated animals. We show that this local increase in CREB activity completely rescued the anxiety phenotype of the isolated animals, as well as their deficit in initiating sexual behavior, but failed to rescue the deficit in ejaculation. Our data suggest a role for the nucleus accumbens in anxiety responses and in specific aspects of sexual behavior. The results also provide insight into the molecular mechanisms by which social interactions affect brain plasticity and behavior. PMID:15923261

Reducing Overutilization of Testing for Clostridium difficile Infection in a Pediatric Hospital System: A Quality Improvement Initiative.

PubMed

Klatte, J Michael; Selvarangan, Rangaraj; Jackson, Mary Anne; Myers, Angela L

2016-01-01

Study objectives included addressing overuse of Clostridium difficile laboratory testing by decreasing submission rates of nondiarrheal stool specimens and specimens from children ≤12 months of age and determining resultant patient and laboratory cost savings associated with decreased testing. A multifaceted initiative was developed, and components included multiple provider education methods, computerized order entry modifications, and automatic declination from laboratory on testing stool specimens of nondiarrheal consistency and from children ≤12 months old. A run chart, demonstrating numbers of nondiarrheal plus infant stool specimens submitted over time, was developed to analyze the initiative's impact on clinicians' test-ordering practices. A p-chart was generated to evaluate the percentage of these submitted specimens tested biweekly over a 12-month period. Cost savings for patients and the laboratory were assessed at the study period's conclusion. Run chart analysis revealed an initial shift after the interventions, suggesting a temporary decrease in testing submission; however, no sustained differences in numbers of specimens submitted biweekly were observed over time. On the p-chart, the mean percentage of specimens tested before the intervention was 100%. After the intervention, the average percentage of specimens tested dropped to 53.8%. Resultant laboratory cost savings totaled nearly $3600, and patient savings on testing charges were ∼$32 000. Automatic laboratory declination of nondiarrheal stools submitted for CDI testing resulted in a sustained decrease in the number of specimens tested, resulting in significant laboratory and patient cost savings. Despite multiple educational efforts, no sustained changes in physician ordering practices were observed. Copyright © 2016 by the American Academy of Pediatrics.

Correlation between Charge Contrast Imaging and the Distribution of Some Trace Level Impurities in Gibbsite

NASA Astrophysics Data System (ADS)

Baroni, Travis C.; Griffin, Brendan J.; Browne, James R.; Lincoln, Frank J.

2000-01-01

Charge contrast images (CCI) of synthetic gibbsite obtained on an environmental scanning electron microscope gives information on the crystallization process. Furthermore, X-ray mapping of the same grains shows that impurities are localized during the initial stages of growth and that the resulting composition images have features similar to these observed in CCI. This suggests a possible correlation between impurity distributions and the emission detected during CCI. X-ray line profiles, simulating the spatial distribution of impurities derived from the Monte Carlo program CASINO, have been compared with experimental line profiles and give an estimate of the localization. The model suggests that a main impurity, Ca, is depleted from the solution within approximately 3 4 [mu]m of growth.

Success rate and risk factors for failure of empirical antifungal therapy with itraconazole in patients with hematological malignancies: a multicenter, prospective, open-label, observational study in Korea.

PubMed

Kim, Soo-Jeong; Cheong, June-Won; Min, Yoo Hong; Choi, Young Jin; Lee, Dong-Gun; Lee, Je-Hwan; Yang, Deok-Hwan; Lee, Sang Min; Kim, Sung-Hyun; Kim, Yang Soo; Kwak, Jae-Yong; Park, Jinny; Kim, Jin Young; Kim, Hoon-Gu; Kim, Byung Soo; Ryoo, Hun-Mo; Jang, Jun Ho; Kim, Min Kyoung; Kang, Hye Jin; Cho, In Sung; Mun, Yeung Chul; Jo, Deog-Yeon; Kim, Ho Young; Park, Byeong-Bae; Kim, Jin Seok

2014-01-01

We assessed the success rate of empirical antifungal therapy with itraconazole and evaluated risk factors for predicting the failure of empirical antifungal therapy. A multicenter, prospective, observational study was performed in patients with hematological malignancies who had neutropenic fever and received empirical antifungal therapy with itraconazole at 22 centers. A total of 391 patients who had abnormal findings on chest imaging tests (31.0%) or a positive result of enzyme immunoassay for serum galactomannan (17.6%) showed a 56.5% overall success rate. Positive galactomannan tests before the initiation of the empirical antifungal therapy (P=0.026, hazard ratio [HR], 2.28; 95% confidence interval [CI], 1.10-4.69) and abnormal findings on the chest imaging tests before initiation of the empirical antifungal therapy (P=0.022, HR, 2.03; 95% CI, 1.11-3.71) were significantly associated with poor outcomes for the empirical antifungal therapy. Eight patients (2.0%) had premature discontinuation of itraconazole therapy due to toxicity. It is suggested that positive galactomannan tests and abnormal findings on the chest imaging tests at the time of initiation of the empirical antifungal therapy are risk factors for predicting the failure of the empirical antifungal therapy with itraconazole. (Clinical Trial Registration on National Cancer Institute website, NCT01060462).

Evolution of magnetic flux ropes associated with flux transfer events and interplanetary magnetic clouds

NASA Technical Reports Server (NTRS)

Wei, C. Q.; Lee, L. C.; Wang, S.; Akasofu, S.-I.

1991-01-01

Spacecraft observations suggest that flux transfer events and interplanetary magnetic clouds may be associated with magnetic flux ropes which are magnetic flux tubes containing helical magnetic field lines. In the magnetic flux ropes, the azimuthal magnetic field is superposed on the axial field. The time evolution of a localized magnetic flux rope is studied. A two-dimensional compressible MHD simulation code with a cylindrical symmetry is developed to study the wave modes associated with the evolution of flux ropes. It is found that in the initial phase both the fast magnetosonic wave and the Alfven wave are developed in the flux rope. After this initial phase, the Alfven wave becomes the dominant wave mode for the evolution of the magnetic flux rope and the radial expansion velocity of the flux rope is found to be negligible. Numerical results further show that even for a large initial azimuthal component of the magnetic field, the propagation velocity along the axial direction of the flux rope remains the Alfven velocity. It is also found that the localized magnetic flux rope tends to evolve into two separate magnetic ropes propagating in opposite directions. The simulation results are used to study the evolution of magnetic flux ropes associated with flux transfer events observed at the earth's dayside magnetopause and magnetic clouds in the interplanetary space.

Inactivation of Mycobacterium avium with free chlorine.

PubMed

Luh, Jeanne; Mariñas, Benito J

2007-07-15

The inactivation kinetics of Mycobacterium avium with free chlorine was characterized by two stages: an initial phase at a relatively fast rate followed by a slower second stage of pseudo first-order kinetics. The inactivation rate of each stage was approximately the same for all experiments performed at a certain condition of pH and temperature; however, variability was observed for the disinfectant exposure at which the transition between the two stages occurred. This variability was not a function of the initial disinfectant concentration, the initial bacterial density, or the bacterial stock. However, the transition to the second stage varied more significantly at high temperatures (30 degrees C), while lower variability was observed at lower temperatures (5 and 20 degrees C). Experiments conducted at pH values in the range of 6-9 revealed that the inactivation of M. avium was primarily due to hypochlorous acid, with little contribution from hypochlorite ion within this pH range. The inactivation kinetics was represented with a two-population model. The activation energies for the resulting pseudo first-order rate constants for the populations with fast and slow kinetics were 100.3 and 96.5 kJ/mol, respectively. The magnitude of these values suggested that for waters of relatively high pH and low temperatures, little inactivation of M. avium would be achieved within treatment plants, providing a seeding source for distribution systems.

Trends in CD4 cell count response to first-line antiretroviral treatment in HIV-positive patients from Asia, 2003-2013: TREAT Asia HIV Observational Database Low Intensity Transfer.

PubMed

De La Mata, Nicole L; Ly, Penh S; Ng, Oon T; Nguyen, Kinh V; Merati, Tuti P; Pham, Thuy T; Lee, Man P; Choi, Jun Y; Sohn, Annette H; Law, Matthew G; Kumarasamy, Nagalingeswaran

2017-11-01

Antiretroviral treatment (ART) guidelines have changed over the past decade, recommending earlier initiation and more tolerable regimens. The study objective was to examine the CD4 response to ART, depending on the year of ART initiation, in HIV-positive patients in the Asia-Pacific. We included HIV-positive adult patients who initiated ART between 2003 and 2013 in our regional cohort from eight urban referral centres in seven countries within Asia. We used mixed-effects linear regression models to evaluate differences in CD4 response by year of ART initiation during 36 months of follow-up, adjusted a priori for other covariates. Overall, 16,962 patients were included. Patients initiating in 2006-9 and 2010-13 had an estimated mean CD4 cell count increase of 8 and 15 cells/µl, respectively, at any given time during the 36-month follow-up, compared to those in 2003-5. The median CD4 cell count at ART initiation also increased from 96 cells/µl in 2003-5 to 173 cells/µl in 2010-13. Our results suggest that the CD4 response to ART is modestly higher for those initiating ART in more recent years. Moreover, fewer patients are presenting with lower absolute CD4 cell counts over time. This is likely to reduce their risk of opportunistic infections and future non-AIDS defining cancers.

Depth dependence of earthquake frequency-magnitude distributions in California: Implications for rupture initiation

USGS Publications Warehouse

Mori, J.; Abercrombie, R.E.

1997-01-01

Statistics of earthquakes in California show linear frequency-magnitude relationships in the range of M2.0 to M5.5 for various data sets. Assuming Gutenberg-Richter distributions, there is a systematic decrease in b value with increasing depth of earthquakes. We find consistent results for various data sets from northern and southern California that both include and exclude the larger aftershock sequences. We suggest that at shallow depth (???0 to 6 km) conditions with more heterogeneous material properties and lower lithospheric stress prevail. Rupture initiations are more likely to stop before growing into large earthquakes, producing relatively more smaller earthquakes and consequently higher b values. These ideas help to explain the depth-dependent observations of foreshocks in the western United States. The higher occurrence rate of foreshocks preceding shallow earthquakes can be interpreted in terms of rupture initiations that are stopped before growing into the mainshock. At greater depth (9-15 km), any rupture initiation is more likely to continue growing into a larger event, so there are fewer foreshocks. If one assumes that frequency-magnitude statistics can be used to estimate probabilities of a small rupture initiation growing into a larger earthquake, then a small (M2) rupture initiation at 9 to 12 km depth is 18 times more likely to grow into a M5.5 or larger event, compared to the same small rupture initiation at 0 to 3 km. Copyright 1997 by the American Geophysical Union.

Remotely-sensed and field-based observations of glacier change in the Annapurna-Manaslu region, Nepal

NASA Astrophysics Data System (ADS)

Lovell, Arminel; Carr, Rachel; Stokes, Chris

2017-04-01

Himalayan glaciers have shrunk rapidly during the past twenty years. Understanding the factors controlling these losses is vital for forecasting changes in water resources, as the Himalaya houses the headwaters of major river systems, with densely populated catchments downstream. However, our knowledge of Himalayan glaciers is comparatively limited, due to their high-altitude, remote location. This is particularly the case in the Annapurna-Manaslu region, which has received relatively little scientific attention to date. Here, we present initial findings from remotely sensed data analysis, and our first field campaign in October 2016. Feature tracking of Band 8 Landsat imagery demonstrates that velocities in the region reach a maximum of 70-100 m a-1 , which is somewhat faster than those reported in the Khumbu region (e.g. Quincey et al 2009). A number of glaciers have substantial stagnant ice tongues, and most are flowing faster in the upper ablation zone than in the lower sections. The most rapidly flowing glaciers are located in the south-east of the Annapurna-Manaslu region and tend to also be the largest. Interestingly, initial observations suggest that the debris-covered ablation zones in the south-east are flowing more rapidly than the smaller, clean-ice glaciers in the north of the region. Comparison of velocities between 2000-2001 and 2014-2015 suggests deceleration on some glacier tongues. In October 2016, we conducted fieldwork on Annapurna South Glacier, located at the foot of Annapurna I. Here, we collected a number of datasets, with the aim of assessing the relationship between surface elevation change, ice velocities and debris cover. These included: i) installing ablation stakes in areas with varying debris cover; ii) quantifying debris characteristics, using Wolman counting and by measuring thickness; iii) surveying the glacier surface, using a differential GPS; iv) monitoring ice cliff melting, using Structure from Motion and; v) measuring surface and sub-surface temperatures, using i-buttons. Initial results demonstrate large spatial variability in debris characteristics and thickness, which in turn appears to substantially influence melt rates. The surface topography is highly uneven and a number of ice cliffs are present, where melt rates appear to be much higher than in surrounding areas. Interestingly, we observed very few surface melt ponds or surface melt water, which we suggest maybe be due to the basal topography and/or debris characteristics, and aim to further investigate this during our 2017 fieldwork.

Incipient boninitic arc crust built on denudated mantle: the Khantaishir ophiolite (western Mongolia)

NASA Astrophysics Data System (ADS)

Gianola, Omar; Schmidt, Max W.; Jagoutz, Oliver; Sambuu, Oyungerel

2017-12-01

The 570 Ma old Khantaishir ophiolite is built by up to 4 km harzburgitic mantle with abundant pyroxenites and dunites followed by 2 km of hornblende-gabbros and gabbronorites and by a 2.5 km thick volcanic unit composed of a dyke + sill complex capped by pillow lavas and some volcanoclastics. The volcanics are mainly basaltic andesites and andesites (or boninites) with an average of 58.2 ± 1.0 wt% SiO2, X Mg = 0.61 ± 0.03 ( X Mg = molar MgO/(MgO + FeOtot), TiO2 = 0.4 ± 0.1 wt% and CaO = 7.5 ± 0.6 wt% (errors as 2 σ). Normalized trace element patterns show positive anomalies for Pb and Sr, a negative Nb-anomaly, large ion lithophile elements (LILE) concentrations between N- and E-MORB and distinctly depleted HREE. These characteristics indicate that the Khantaishir volcanics were derived from a refractory mantle source modified by a moderate slab-component, similar to boninites erupted along the Izu-Bonin-Mariana subduction system and to the Troodos and Betts Cove ophiolites. Most strikingly and despite almost complete outcrops over 260 km2, there is no remnant of any pre-existing MORB crust, suggesting that the magmatic suite of this ophiolite formed on completely denudated mantle, most likely upon subduction initiation. The architecture of this 4-5 km thick early arc crust resembles oceanic crust formed at mid ocean ridges, but lacks a sheeted dyke complex; volcanic edifices are not observed. Nevertheless, low melting pressures combined with moderate H2O-contents resulted in high-Si primitive melts, in abundant hornblende-gabbros and in a fast enrichment in bulk SiO2. Fractional crystallization modeling starting from the observed primitive melts (56.6 wt% SiO2) suggests that 25 wt% pyroxene + plagioclase fractionation is sufficient to form the average Khantaishir volcanic crust. Most of the fractionation happened in the mantle, the observed pyroxenite lenses and layers in and at the top of the harzburgites account for the required cumulate volumes. Finally, the multiply documented occurrence of highly depleted boninites during subduction initiation suggests a causal relationship of subduction initiation and highly depleted mantle. Possibly, a discontinuity between dense fertile and buoyant depleted mantle contributes to the sinking of the future dense subducting plate, while the buoyant depleted mantle of the future overriding plate forms the infant mantle wedge.

Sediment toxicity identification evaluation (TIE) studies at marine sites suspected of ordnance contamination

USGS Publications Warehouse

Carr, R.S.; Nipper, M.; Biedenbach, J.M.; Hooten, R.L.; Miller, K.; Saepoff, S.

2001-01-01

A sediment quality assessment survey and subsequent toxicity identification evaluation (TIE) study was conducted at several sites in Puget Sound, Washington. The sites were previously suspected of contamination with ordnance compounds. The initial survey employed sea urchin porewater toxicity tests to locate the most toxic stations. Sediments from the most toxic stations were selected for comprehensive chemical analyses. Based on the combined information from the toxicity and chemical data, three adjacent stations in Ostrich Bay were selected for the TIE study. The results of the phase I TIE suggested that organics and metals were primarily responsible for the observed toxicity in the sea urchin fertilization test. In addition to these contaminants, ammonia was also contributing to the toxicity for the sea urchin embryological development test. The phase II TIE study isolated the majority of the toxicity in the fraction containing nonpolar organics with high log Kow, but chemical analyses failed to identify a compound present at a concentration high enough to be responsible for the observed toxicity. The data suggest that some organic or organometallic contaminant(s) that were not included in the comprehensive suite of chemical analyses caused the observed toxicological responses.

Direct microscopic observation of forward osmosis membrane fouling.

PubMed

Wang, Yining; Wicaksana, Filicia; Tang, Chuyang Y; Fane, Anthony G

2010-09-15

This study describes the application of a noninvasive direct microscopic observation method for characterizing fouling of a forward osmosis (FO) membrane. The effect of the draw solution concentration, membrane orientation, and feed spacer on FO fouling was systematically investigated in a cross-flow setup using latex particles as model foulant in the feedwater. Higher draw solution (DS) concentrations (and thus increased flux levels) resulted in dramatic increase in the surface coverage by latex particles, suggesting that the critical flux concept might be applicable even for the osmotically driven FO process. Under identical draw solution concentrations, the active-layer-facing-the-feed-solution orientation (AL-FS) experienced significantly less fouling compared to the alternative orientation. This may be explained by the lower water flux in AL-FS, which is consistent with the critical flux concept. The use of a feed spacer not only dramatically enhanced the initial flux of the FO membrane, but also significantly improved the flux stability during FO fouling. Despite such beneficial effects of using the feed spacer, a significant amount of particle accumulation was found near the spacer filament, suggesting further opportunities for improved spacer design. To the best of the authors' knowledge, this is the first direct microscopic observation study on FO fouling.

The Doctrine of Original Antigenic Sin: Separating Good From Evil.

PubMed

Monto, Arnold S; Malosh, Ryan E; Petrie, Joshua G; Martin, Emily T

2017-06-15

The term "original antigenic sin" was coined approximately 60 years ago to describe the imprinting by the initial first influenza A virus infection on the antibody response to subsequent vaccination. These studies did not suggest a reduction in the response to current antigens but instead suggested anamnestic recall of antibody to earlier influenza virus strains. Then, approximately 40 years ago, it was observed that sequential influenza vaccination might lead to reduced vaccine effectiveness (VE). This conclusion was largely dismissed after an experimental study involving sequential administration of then-standard influenza vaccines. Recent observations have provided convincing evidence that reduced VE after sequential influenza vaccination is a real phenomenon. We propose that such reduction in VE be termed "negative antigenic interaction," given that there is no age cohort effect. In contrast, the potentially positive protective effect of early influenza virus infection later in life continues to be observed. It is essential that we understand better the immunologic factors underlying both original antigenic sin and negative antigenic interaction, to support development of improved influenza vaccines and vaccination strategies. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America.

Fungal degradation of fiber-reinforced composite materials

NASA Technical Reports Server (NTRS)

Gu, J. D.; Lu, C.; Mitchell, R.; Thorp, K.; Crasto, A.

1997-01-01

As described in a previous report, a fungal consortium isolated from degraded polymeric materials was capable of growth on presterilized coupons of five composites, resulting in deep penetration into the interior of all materials within five weeks. Data describing the utilization of composite constituents as nutrients for the microflora are described in this article. Increased microbial growth was observed when composite extract was incubated with the fungal inoculum at ambient temperatures. Scanning electron microscopic observation of carbon fibers incubated with a naturally developed population of microorganisms showed the formation of bacterial biofilms on the fiber surfaces, suggesting possible utilization of the fiber chemical sizing as carbon and energy sources. Electrochemical impedance spectroscopy was used to monitor the phenomena occurring at the fiber-matrix interfaces. Significant differences were observed between inoculated and sterile panels of the composite materials. A progressive decline in impedance was detected in the inoculated panels. Several reaction steps may be involved in the degradation process. Initial ingress of water into the resin matrix appeared to be followed by degradation of fiber surfaces, and separation of fibers from the resin matrix. This investigation suggested that composite materials are susceptible to microbial attack by providing nutrients for growth.

Recurring slope lineae in equatorial regions of Mars

USGS Publications Warehouse

McEwen, Alfred S.; Dundas, Colin M.; Mattson, Sarah S.; Toigo, Anthony D.; Ojha, Lujendra; Wray, James J.; Chojnacki, Matthew; Byrne, Shane; Murchie, Scott L.; Thomas, Nicolas

2014-01-01

The presence of liquid water is a requirement of habitability on a planet. Possible indicators of liquid surface water on Mars include intermittent flow-like features observed on sloping terrains. These recurring slope lineae are narrow, dark markings on steep slopes that appear and incrementally lengthen during warm seasons on low-albedo surfaces. The lineae fade in cooler seasons and recur over multiple Mars years. Recurring slope lineae were initially reported to appear and lengthen at mid-latitudes in the late southern spring and summer and are more common on equator-facing slopes where and when the peak surface temperatures are higher. Here we report extensive activity of recurring slope lineae in equatorial regions of Mars, particularly in the deep canyons of Valles Marineris, from analysis of data acquired by the Mars Reconnaissance Orbiter. We observe the lineae to be most active in seasons when the slopes often face the sun. Expected peak temperatures suggest that activity may not depend solely on temperature. Although the origin of the recurring slope lineae remains an open question, our observations are consistent with intermittent flow of briny water. Such an origin suggests surprisingly abundant liquid water in some near-surface equatorial regions of Mars.

Experimental ductile reactivation of pseudotachylyte-bearing faults.

NASA Astrophysics Data System (ADS)

Tielke, J.; Di Toro, G.; Passelegue, F. X.; Mecklenburgh, J.

2017-12-01

In most large earthquakes, afterslip is primarily accommodated by ductile deformation in the deep crust and upper mantle. In the last decades, field and experimental studies highlighted that seismic rupture can induce frictional meltin. The product of frictional melting, called pseudotachylyte, is considered the best signature of seismic rupture in exposed sections of rocks. Deformation of pseudotachylyte in the deep crust may explain the observed reduction of the strength after earthquakes, providing an explanation for the large afterslip or creep phenomena. In addition, the observation of natural mylonitized pseudotachylytes confirms the hypothesis of ductile reactivations. In this study, we conducted experiments under deep crust PT conditions on natural pseudotachylyte and tonalite from the Gole Larghe fault zone. Deformation experiments were carried out using a gas-medium apparatus at temperatures of 700° to 900°C, a confining pressure of 300 MPa, differential stresses stages of 5 to 400 MPa resulting in different strain rates. Mechanical data were used to derive flow law parameters. The intact tonalite present the largest strength of the rocks tested. The deformation mechanisms remain mostly brittle even at 900°C, and experiments finished by the brittle failure of the rock specimens. In pseudotachylyte-bearing tonalite, strain is strongly localized within pseudotachylyte-rich regions. While the rocks samples remain strong at 700°C , weakening initiates at 800°C. The dependence of strain rate on stress follows a power-law relationship with a stress exponent (n) of 1 at low differential stress, and 3 at high differential stress. At 900°C, the strength of the pseudotachylyte vein samples drastically weakens and values of n of 3 are observed even at low differential stress. Microstructural analyses demonstrate that strain localization in pseudotachylite-bearing rocks corresponds with the initiation of partial melting at 800°C. In contrast, tonalite that is free of pseudotachylite only exhibits brittle processes. Evidence of the initiation of mylonitization is observed at low strain conditions. Our results suggest that the presence of pseudotachylyte in crustal rocks drastically reduces the strength of the system when the temperature allows for initiation of partial melting.

The role of serial free/total prostate-specific antigen ratios in a watchful observation protocol for men with localized prostate cancer.

PubMed

Do, V; Choo, R; De Boer, G; Klotz, L; Danjoux, C; Morton, G; Szumacher, E; Fleshner, N; Bunting, P

2002-05-01

To examine the change in the free/total prostate specific antigen ratio (f/tPSA) with time and to assess the potential value of serial measurements of f/tPSA as a determinant of disease progression in untreated, low-to-intermediate grade prostate cancer (T1b-T2b N0M0, Gleason score < or = 7 and PSA < or = 15 ng/mL). In a prospective single-arm cohort study from November 1995, patients were conservatively managed with watchful observation alone unless they met arbitrarily defined criteria (clinical, histological and biochemical) of disease progression. Patients were followed regularly and underwent blood tests including PSA and f/tPSA. The initial and mean f/tPSA and the rate of change of f/tPSA with time were evaluated against the rate constant for the PSA doubling time (PSATd). Correlation analyses were used to evaluate any association between baseline clinical variables and either the rate of change of f/tPSA or initial f/tPSA. As of December 2000, 161 of a total of 206 accrued patients had three or more f/tPSA measurements and formed the basis of the study (median age 70 years; median follow-up 2.7 years). The median initial f/tPSA was 0.16; there was a significant negative correlation between this value and the initial total PSA. The mean f/tPSA and rate of change of f/tPSA with time were significantly negatively correlated with the rate constant for PSATd. Also, the rate of change of f/tPSA correlated negatively with clinical T stage, but not with other baseline variables, including initial PSA, age and Gleason score. The f/tPSA in men with untreated, clinically localized prostate cancer varied widely. The negative correlation between the rate of change of f/tPSA with time and rate constant for PSATd suggests that both might provide valuable information to allow clinicians to develop a strategy for optimizing the timing of therapeutic intervention for those patients choosing watchful observation alone.

Computational modelling and analysis of the molecular network regulating sporulation initiation in Bacillus subtilis.

PubMed

Ihekwaba, Adaoha E C; Mura, Ivan; Barker, Gary C

2014-10-24

Bacterial spores are important contaminants in food, and the spore forming bacteria are often implicated in food safety and food quality considerations. Spore formation is a complex developmental process involving the expression of more than 500 genes over the course of 6 to 8 hrs. The process culminates in the formation of resting cells capable of resisting environmental extremes and remaining dormant for long periods of time, germinating when conditions promote further vegetative growth. Experimental observations of sporulation and germination are problematic and time consuming so that reliable models are an invaluable asset in terms of prediction and risk assessment. In this report we develop a model which assists in the interpretation of sporulation dynamics. This paper defines and analyses a mathematical model for the network regulating Bacillus subtilis sporulation initiation, from sensing of sporulation signals down to the activation of the early genes under control of the master regulator Spo0A. Our model summarises and extends other published modelling studies, by allowing the user to execute sporulation initiation in a scenario where Isopropyl β-D-1-thiogalactopyranoside (IPTG) is used as an artificial sporulation initiator as well as in modelling the induction of sporulation in wild-type cells. The analysis of the model results and the comparison with experimental data indicate that the model is good at predicting inducible responses to sporulation signals. However, the model is unable to reproduce experimentally observed accumulation of phosphorelay sporulation proteins in wild type B. subtilis. This model also highlights that the phosphorelay sub-component, which relays the signals detected by the sensor kinases to the master regulator Spo0A, is crucial in determining the response dynamics of the system. We show that there is a complex connectivity between the phosphorelay features and the master regulatory Spo0A. Additional we discovered that the experimentally observed regulation of the phosphotransferase Spo0B for wild-type B. subtilis may be playing an important role in the network which suggests that modelling of sporulation initiation may require additional experimental support.

Thermo-mechanical models of obduction applied to the Oman ophiolite

NASA Astrophysics Data System (ADS)

Thibault, Duretz; Philippe, Agard; Philippe, Yamato; Céline, Ducassou; Taras, Gerya; Evguenii, Burov

2015-04-01

During obduction regional-scale fragments of oceanic lithosphere (ophiolites) are emplaced somewhat enigmatically on top of lighter continental lithosphere. We herein use two-dimensional thermo-mechanical models to investigate the feasibility and controlling parameters of obduction. The models are designed using available geological data from the Oman (Semail) ophiolite. Initial and boundary conditions are constrained by plate kinematic and geochronological data and modeling results are validated against petrological and structural observations. The reference model consists of three distinct stages: (1) initiation of oceanic subduction initiation away from Arabian margin, (2) emplacement of the Oman Ophiolite atop the Arabian margin, (2) dome-like exhumation of the subducted Arabian margin beneath the overlying ophiolite. A parametric study suggests that 350-400 km of shortening allows to best fit both the peak P-T conditions of the subducted margin (1.5-2.5 GPa / 450-600°C) and the dimensions of the ophiolite (~170 km width), in agreement with previous estimations. Our results further confirm that the locus of obduction initiation is close to the eastern edge of the Arabian margin (~100 km) and indicate that obduction is facilitated by a strong continental basement rheology.

Learned recognition of maternal signature odors mediates the first suckling episode in mice

PubMed Central

Logan, Darren W.; Brunet, Lisa J.; Webb, William R.; Cutforth, Tyler; Ngai, John; Stowers, Lisa

2012-01-01

Summary Background Soon after birth all mammals must initiate milk suckling to survive. In rodents, this innate behavior is critically dependent on uncharacterized maternally-derived chemosensory ligands. Recently the first pheromone sufficient to initiate suckling was isolated from the rabbit. Identification of the olfactory cues that trigger first suckling in the mouse would provide the means to determine the neural mechanisms that generate innate behavior. Results Here we use behavioral analysis, metabolomics, and calcium imaging of primary sensory neurons and find no evidence of ligands with intrinsic bioactivity, such as pheromones, acting to promote first suckling in the mouse. Instead, we find that the initiation of suckling is dependent on variable blends of maternal ‘signature odors’ that are learned and recognized prior to first suckling. Conclusions As observed with pheromone-mediated behavior, the response to signature odors releases innate behavior. However, this mechanism tolerates variability in both the signaling ligands and sensory neurons which may maximize the probability that this first essential behavior is successfully initiated. These results suggest that mammalian species have evolved multiple strategies to ensure the onset of this critical behavior. PMID:23041191

Multi-Layer Arctic Mixed-Phase Clouds Simulated by a Cloud-Resolving Model: Comparison with ARM Observations and Sensitivity Experiments

NASA Technical Reports Server (NTRS)

Luo, Yali; Xu, Kuan-Man; Morrison, Hugh; McFarquhar, Greg M.; Wang, Zhien; Zhang, Gong

2007-01-01

A cloud-resolving model (CRM) is used to simulate the multiple-layer mixed-phase stratiform (MPS) clouds that occurred during a three-and-a-half day subperiod of the Department of Energy-Atmospheric Radiation Measurement Program s Mixed-Phase Arctic Cloud Experiment (M-PACE). The CRM is implemented with an advanced two-moment microphysics scheme, a state-of-the-art radiative transfer scheme, and a complicated third-order turbulence closure. Concurrent meteorological, aerosol, and ice nucleus measurements are used to initialize the CRM. The CRM is prescribed by time-varying large-scale advective tendencies of temperature and moisture and surface turbulent fluxes of sensible and latent heat. The CRM reproduces the occurrences of the single- and double-layer MPS clouds as revealed by the M-PACE observations. However, the simulated first cloud layer is lower and the second cloud layer thicker compared to observations. The magnitude of the simulated liquid water path agrees with that observed, but its temporal variation is more pronounced than that observed. As in an earlier study of single-layer cloud, the CRM also captures the major characteristics in the vertical distributions and temporal variations of liquid water content (LWC), total ice water content (IWC), droplet number concentration and ice crystal number concentration (nis) as suggested by the aircraft observations. However, the simulated mean values differ significantly from the observed. The magnitude of nis is especially underestimated by one order of magnitude. Sensitivity experiments suggest that the lower cloud layer is closely related to the surface fluxes of sensible and latent heat; the upper cloud layer is probably initialized by the large-scale advective cooling/moistening and maintained through the strong longwave (LW) radiative cooling near the cloud top which enhances the dynamical circulation; artificially turning off all ice-phase microphysical processes results in an increase in LWP by a factor of 3 due to interactions between the excessive LW radiative cooling and extra cloud water; heating caused by phase change of hydrometeors could affect the LWC and cloud top height by partially canceling out the LW radiative cooling. It is further shown that the resolved dynamical circulation appears to contribute more greatly to the evolution of the MPS cloud layers than the parameterized subgrid-scale circulation.

CT findings in ulcerative, granulomatous, and indeterminate colitis

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

Gore, R.M.; Marn, C.S.; Kirby, D.F.

1984-08-01

Eight patients with ulcerative colitis, three with colitis indeterminate, and 15 patients with Crohn disease were studied by computed tomography (CT) to establish CT criteria for each disorder in hopes of providing a new diagnostic perspective useful in the radiographic evaluation of inflammatory colitis. The CT findings in ulcerative colitis included thickening of the colon wall, which was characterized by inhomogeneous attenuation and a target appearance of the rectum, and proliferation of perirectal fat. Bowel wall thickening with homogeneous attenuation, fistula and abscess formation, and mesenteric abnormalities were observed in patients with Crohn colitis. Patients with colitis indeterminate showed colonicmore » changes on CT observed in both disorders. Initial experience suggests that CT can differentiate patients with well established ulcerative and Crohn colitis.« less

Behavioral school psychology goes outdoors: the effect of organized games on playground aggression.

PubMed

Murphy, H A; Hutchison, J M; Bailey, J S

1983-01-01

This research focuses on the inappropriate, largely aggressive, behaviors of 344 K-2 children assigned to a playground prior to the beginning of the school day. Initially, a system for observing large numbers of children freely roaming over a large, open area was developed. This observational method was then used to determine the effectiveness of providing organized games for reducing potentially dangerous playground behaviors. Using a reversal (ABAB) design, it was found that the games, rope jumping, and foot racing, along with an infrequently used time-out procedure, significantly reduced the frequency of inappropriate incidents. It is suggested that when dealing with large groups, antecedent environmental manipulations may be more practical than providing consequences for the behaviors exhibited by identified individuals.

Filament cooling and condensation in a sheared magnetic field

NASA Technical Reports Server (NTRS)

Van Hoven, Gerard

1990-01-01

Thermal instability driven by optically thin radiation in the corona is believed to initiate the formation of solar filaments. The fact that filaments are observed generally to separate regions of opposite, line-of-sight, magnetic polarity in the differentially rotating photosphere suggests that filament formation requires the presence of a highly sheared magnetic field. The coupled energetics and dynamics of the most important condensation modes, those due to perpendicular thermal conduction at short wavelengths are discussed. Linear structure in the sheared field and their growth rates is described, and 2D, nonlinear, MHD simulations of the evolution of these modes in a force-free field are conducted. The simulations achieve the fine thermal structures, minimum temperatures and maximum densities characteristic of observed solar filaments.

DMSP F7 observations of a substorm field-aligned current

NASA Technical Reports Server (NTRS)

Lopez, R. E.; Spence, H. E.; Meng, C.-I.

1991-01-01

Observations are described of a substorm field-aligned current (FAC) system traversed by the DMSP F7 spacecraft just after 0300 UT on April 25, 1985. It is shown that the substorm FAC portion of the current system was located equatorward of the boundary between open and closed field lines. The equatorward boundary of the substorm FAC into the magnetotail was mapped using the Tsyganenko (1987) model, showing that the boundary corresponds to 6.9 earth radii. The result is consistent with the suggestion of Akasofu (1972) and Lopez and Lui (1990) that the region of substorm initiation lies relatively close to the earth and the concept that an essential feature of substorms is the disruption and diversion of the near-earth current sheet.

Use of biological assay systems to assess the relative carcinogenic hazards of disinfection by-products.

PubMed Central

Bull, R J; Robinson, M; Meier, J R; Stober, J

1982-01-01

Other workers have clearly shown that most, if not all, drinking water in the U.S. contains chemicals that possess mutagenic and/or carcinogenic activity by using bacterial and in vitro methods. In the present work, increased numbers of tumors were observed with samples of organic material isolated from 5 U.S. cities administered as tumor initiators in mouse skin initiation/promotion studies. Only in one case was the result significantly different from control. In studies designed to test whether disinfection practice contributes significantly to the tumor initiating activity found in drinking water mixed results have been obtained. In one experiment, water disinfected by chlorination, ozonation or combined chlorine resulted in a significantly greater number of papillomas when compared to nondisinfected water. In two subsequent experiments, where water was obtained from the Ohio River at different times of the year, no evidence of increased initiating activity was observed with any disinfectant. Analysis of water obtained at the comparable times of the year for total organic halogen, and trihalomethane formation revealed a substantial variation in the formation of these products. Considering the problems such variability poses for estimating risks associated with disinfection by-products, a model system which makes use of commercially obtained humic acid as a substrate for chlorination was investigated using the Ames test. Humic and fulvic acids obtained from two surface waters as well as the commercially obtained humic acid were without activity in TA 1535, TA 1537, TA 1538, TA 98 or TA 100 strains of S. typhimurium. Following treatment with a 0.8 molar ratio of chlorine (based on carbon) significant mutagenic activity was observed with all humic and fulvic acid samples. Comparisons of the specific mutagenic activity of the chlorinated products suggests that the commercial material might provide a useful model for studying health hazards associated with disinfection reactions by-products. PMID:7151763

MHD Modelling of Coronal Loops: Injection of High-Speed Chromospheric Flows

NASA Technical Reports Server (NTRS)

Petralia, A.; Reale, F.; Orlando, S.; Klimchuk, J. A.

2014-01-01

Context. Observations reveal a correspondence between chromospheric type II spicules and bright upward-moving fronts in the corona observed in the extreme-ultraviolet (EUV) band. However, theoretical considerations suggest that these flows are probably not the main source of heating in coronal magnetic loops. Aims. We investigate the propagation of high-speed chromospheric flows into coronal magnetic flux tubes and the possible production of emission in the EUV band. Methods. We simulated the propagation of a dense 104 K chromospheric jet upward along a coronal loop by means of a 2D cylindrical MHD model that includes gravity, radiative losses, thermal conduction, and magnetic induction. The jet propagates in a complete atmosphere including the chromosphere and a tenuous cool (approximately 0.8 MK) corona, linked through a steep transition region. In our reference model, the jet initial speed is 70 km per second, its initial density is 10(exp 11) per cubic centimeter, and the ambient uniform magnetic field is 10 G. We also explored other values of jet speed and density in 1D and different magnetic field values in 2D, as well as the jet propagation in a hotter (approximately 1.5 MK) background loop. Results. While the initial speed of the jet does not allow it to reach the loop apex, a hot shock-front develops ahead of it and travels to the other extreme of the loop. The shock front compresses the coronal plasma and heats it to about 10(exp 6) K. As a result, a bright moving front becomes visible in the 171 Angstrom channel of the SDO/AIA mission. This result generally applies to all the other explored cases, except for the propagation in the hotter loop. Conclusions. For a cool, low-density initial coronal loop, the post-shock plasma ahead of upward chromospheric flows might explain at least part of the observed correspondence between type II spicules and EUV emission excess.

Geophysical observations of Kilauea Volcano, Hawaii, 2. Constraints on the magma supply during November 1975-September 1977

USGS Publications Warehouse

Dzurisin, D.; Anderson, L.A.; Eaton, G.P.; Koyanagi, R.Y.; Lipman, P.W.; Lockwood, J.P.; Okamura, R.T.; Puniwai, G.S.; Sako, M.K.; Yamashita, K.M.

1980-01-01

Following a 22-month hiatus in eruptive activity, Kilauea volcano extruded roughly 35 ?? 106 m3 of tholeiitic basalt from vents along its middle east rift zone during 13 September-1 October, 1977. The lengthy prelude to this eruption began with a magnitude 7.2 earthquake on 29 November, 1975, and included rapid summit deflation episodes in June, July, and August 1976 and February 1977. Synthesis of seismic, geodetic, gravimetric, and electrical self-potential observations suggests the following model for this atypical Kilauea eruptive cycle. Rapid summit deflation initiated by the November 1975 earthquake reflected substantial migration of magma from beneath the summit region of Kilauea into the east and southwest rift zones. Simultaneous leveling and microgravity observations suggest that 40-90 ?? 106 m3 of void space was created within the summit magma chamber as a result of the earthquake. If this volume was filled by magma from depth before the east rift zone intrusive event of June 1976, the average rate of supply was 6-13 ?? 106 m3/month, a rate that is consistent with the value of 9 ?? 106 m3/month suggested from observations of long-duration Kilauea eruptions. Essentially zero net vertical change was recorded at the summit during the 15-month period beginning with the June 1976 intrusion and ending with the September 1977 eruption. This fact suggests that most magma supplied from depth during this interval was eventually delivered to the east rift zone, at least in part during four rapid summit deflation episodes. Microearthquake epicenters migrated downrift to the middle east rift zone for the first time during the later stages of the February 1977 intrusion, an occurrence presumably reflecting movement of magma into the eventual eruptive zone. This observation was confirmed by tilt surveys in May 1977 that revealed a major inflation center roughly 30 km east of the summit in an area of anomalous steaming and forest kill first noted in March 1976. ?? 1980.

Initial genome sequencing and analysis of multiple myeloma

PubMed Central

Chapman, Michael A.; Lawrence, Michael S.; Keats, Jonathan J.; Cibulskis, Kristian; Sougnez, Carrie; Schinzel, Anna C.; Harview, Christina L.; Brunet, Jean-Philippe; Ahmann, Gregory J.; Adli, Mazhar; Anderson, Kenneth C.; Ardlie, Kristin G.; Auclair, Daniel; Baker, Angela; Bergsagel, P. Leif; Bernstein, Bradley E.; Drier, Yotam; Fonseca, Rafael; Gabriel, Stacey B.; Hofmeister, Craig C.; Jagannath, Sundar; Jakubowiak, Andrzej J.; Krishnan, Amrita; Levy, Joan; Liefeld, Ted; Lonial, Sagar; Mahan, Scott; Mfuko, Bunmi; Monti, Stefano; Perkins, Louise M.; Onofrio, Robb; Pugh, Trevor J.; Vincent Rajkumar, S.; Ramos, Alex H.; Siegel, David S.; Sivachenko, Andrey; Trudel, Suzanne; Vij, Ravi; Voet, Douglas; Winckler, Wendy; Zimmerman, Todd; Carpten, John; Trent, Jeff; Hahn, William C.; Garraway, Levi A.; Meyerson, Matthew; Lander, Eric S.; Getz, Gad; Golub, Todd R.

2013-01-01

Multiple myeloma is an incurable malignancy of plasma cells, and its pathogenesis is poorly understood. Here we report the massively parallel sequencing of 38 tumor genomes and their comparison to matched normal DNAs. Several new and unexpected oncogenic mechanisms were suggested by the pattern of somatic mutation across the dataset. These include the mutation of genes involved in protein translation (seen in nearly half of the patients), genes involved in histone methylation, and genes involved in blood coagulation. In addition, a broader than anticipated role of NF-κB signaling was suggested by mutations in 11 members of the NF-κB pathway. Of potential immediate clinical relevance, activating mutations of the kinase BRAF were observed in 4% of patients, suggesting the evaluation of BRAF inhibitors in multiple myeloma clinical trials. These results indicate that cancer genome sequencing of large collections of samples will yield new insights into cancer not anticipated by existing knowledge. PMID:21430775

Europa: Initial Galileo Geological Observations

USGS Publications Warehouse

Greeley, R.; Sullivan, R.; Klemaszewski, J.; Homan, K.; Head, J. W.; Pappalardo, R.T.; Veverka, J.; Clark, B.E.; Johnson, T.V.; Klaasen, K.P.; Belton, M.; Moore, J.; Asphaug, E.; Carr, M.H.; Neukum, G.; Denk, T.; Chapman, C.R.; Pilcher, C.B.; Geissler, P.E.; Greenberg, R.; Tufts, R.

1998-01-01

Images of Europa from the Galileo spacecraft show a surface with a complex history involving tectonic deformation, impact cratering, and possible emplacement of ice-rich materials and perhaps liquids on the surface. Differences in impact crater distributions suggest that some areas have been resurfaced more recently than others; Europa could experience current cryovolcanic and tectonic activity. Global-scale patterns of tectonic features suggest deformation resulting from non-synchronous rotation of Europa around Jupiter. Some regions of the lithosphere have been fractured, with icy plates separated and rotated into new positions. The dimensions of these plates suggest that the depth to liquid or mobile ice was only a few kilometers at the time of disruption. Some surfaces have also been upwarped, possibly by diapirs, cryomagmatic intrusions, or convective upwelling. In some places, this deformation has led to the development of chaotic terrain in which surface material has collapsed and/or been eroded. ?? 1998 Academic Press.

Identification of corrosion and damage mechanisms by using scanning electron microscopy and energy-dispersive X-ray microanalysis: contribution to failure analysis case histories

NASA Astrophysics Data System (ADS)

Pantazopoulos, G.; Vazdirvanidis, A.

2014-03-01

Emphasis is placed on the evaluation of corrosion failures of copper and machineable brass alloys during service. Typical corrosion failures of the presented case histories mainly focussed on stress corrosion cracking and dezincification that acted as the major degradation mechanisms in components used in piping and water supply systems. SEM assessment, coupled with EDS spectroscopy, revealed the main cracking modes together with the root-source(s) that are responsible for the damage initiation and evolution. In addition, fracture surface observations contributed to the identification of the incurred fracture mechanisms and potential environmental issues that stimulated crack initiation and propagation. Very frequently, the detection of chlorides among the corrosion products served as a suggestive evidence of the influence of working environment on passive layer destabilisation and metal dissolution.

Time-dependent efficiency measurements of polymer solar cells with dye additives: unexpected initial increase of efficiency

NASA Astrophysics Data System (ADS)

Bandaccari, Kyle J.; Chesmore, Grace E.; Bugaj, Mitchel; Valverde, Parisa Tajalli-Tehrani; Barber, Richard P.; McNelis, Brian J.

2018-04-01

We report the effects of the addition of two azo-dye additives on the time-dependent efficiency of polymer solar cells. Although the maximum efficiencies of devices containing different amounts of dye do not vary greatly over the selected concentration range, the time dependence results reveal a surprising initial increase in efficiency in some samples. We observe this effect to be correlated with a leakage current, although a specific mechanism is not yet identified. We also present the measured lifetimes of these solar cells, and find that variations in dye concentrations produce a small effect at most. Characterization of the bulk heterojunction layer (active layer) morphology using atomic-force microscope (AFM) imaging reveals reordering patterns which suggest that the primary effects of the dyes arise via structural, not absorptive, characteristics.

Initiation of air ionization by ultrashort laser pulses: evidence for a role of metastable-state air molecules

NASA Astrophysics Data System (ADS)

Bulgakov, A. V.; Mirza, I.; Bulgakova, N. M.; Zhukov, V. P.; Machulka, R.; Haderka, O.; Campbell, E. E. B.; Mocek, T.

2018-06-01

Transmission measurements for femtosecond laser pulses focused in air with spectral analysis of emission from the focal region have been carried out for various pulse energies and air pressures. The air breakdown threshold and pulse attenuation due to plasma absorption are evaluated and compared with calculations based on the multiphoton ionization model. The plasma absorption is found to depend on the pulse repetition rate and is considerably stronger at 1 kHz than at 1–10 Hz. This suggests that accumulation of metastable states of air molecules plays an important role in initiation of air breakdown, enhancing the ionization efficiency at high repetition rates. Possible channels of metastable-state-assisted air ionization and the role of the observed accumulation effect in laser material processing are discussed.

Ultraviolet light-induced keratinocyte apoptosis: a potential mechanism for the induction of skin lesions and autoantibody production in LE.

PubMed

Casciola-Rosen, L; Rosen, A

1997-01-01

Systemic lupus erythematosus (SLE) is a prototype systemic autoimmune disease which is characterized clinically by pleiotropy and periodicity. The immune features which accompany the characteristic flares of the disease have strongly suggested that the autoimmune response is driven by self antigen, and is T cell-dependent. These features have prompted the search for potential initiating process(es) which induce the release of self-antigens in a form which causes T cell tolerance to those self molecules to be broken. We review here several recent observations which implicate apoptotic cells as an important potential source of clustered and concentrated autoantigens in SLE, and present our current model whereby the novel autoantigen fragments generated in apoptotic surface blebs initiate and drive the autoimmune response in this disease.

THE PRE-PENUMBRAL MAGNETIC CANOPY IN THE SOLAR ATMOSPHERE

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

MacTaggart, David; Guglielmino, Salvo L.; Zuccarello, Francesca

2016-11-01

Penumbrae are the manifestation of magnetoconvection in highly inclined (to the vertical direction) magnetic field. The penumbra of a sunspot tends to form, initially, along the arc of the umbra antipodal to the main region of flux emergence. The question of how highly inclined magnetic field can concentrate along the antipodal curves of umbrae, at least initially, remains to be answered. Previous observational studies have suggested the existence of some form of overlying magnetic canopy that acts as the progenitor for penumbrae. We propose that such overlying magnetic canopies are a consequence of how the magnetic field emerges into themore » atmosphere and are, therefore, part of the emerging region. We show, through simulations of twisted flux tube emergence, that canopies of highly inclined magnetic field form preferentially at the required locations above the photosphere.« less

Cell Size Regulation in Bacteria

NASA Astrophysics Data System (ADS)

Amir, Ariel

2014-05-01

Various bacteria such as the canonical gram negative Escherichia coli or the well-studied gram positive Bacillus subtilis divide symmetrically after they approximately double their volume. Their size at division is not constant, but is typically distributed over a narrow range. Here, we propose an analytically tractable model for cell size control, and calculate the cell size and interdivision time distributions, as well as the correlations between these variables. We suggest ways of extracting the model parameters from experimental data, and show that existing data for E. coli supports partial size control, and a particular explanation: a cell attempts to add a constant volume from the time of initiation of DNA replication to the next initiation event. This hypothesis accounts for the experimentally observed correlations between mother and daughter cells as well as the exponential dependence of size on growth rate.

The dark side of testing memory: repeated retrieval can enhance eyewitness suggestibility.

PubMed

Chan, Jason C K; Lapaglia, Jessica A

2011-12-01

Eyewitnesses typically recount their experiences many times before trial. Such repeated retrieval can enhance memory retention of the witnessed event. However, recent studies (e.g., Chan, Thomas, & Bulevich, 2009) have found that initial retrieval can exacerbate eyewitness suggestibility to later misleading information--a finding termed retrieval-enhanced suggestibility (RES). Here we examined the influence of multiple retrieval attempts on eyewitness suggestibility to subsequent misinformation. In four experiments, we systematically varied the number of initial tests taken (between zero and six), the delay between initial testing and misinformation exposure (~30 min or 1 week), and whether initial testing was manipulated between- or within-subjects. University undergraduate students were used as participants. Overall, we found that eyewitness suggestibility increased as the number of initial tests increased, but this RES effect was qualified by the delay and by whether initial testing occurred in a within- or between-subjects manner. Specifically, the within-subjects RES effect was smaller than the between-subjects RES effect, possibly because of the influence of retrieval-induced forgetting/facilitation (Chan, 2009) when initial testing was manipulated within subjects. Moreover, consistent with the testing effect literature (Roediger & Karpicke, 2006), the benefits of repeated testing on later memory were stronger after a 1-week delay than after a 30-min delay, thus reducing the negative impact of RES in long-term situations. These findings suggest that conditions that are likely to occur in criminal investigations can either increase (repeated testing) or reduce (delay) the influence of RES, thus further demonstrating the complex relationship between eyewitness memory and repeated retrieval.

The effect of women's suggestive clothing on men's behavior and judgment: a field study.

PubMed

Guéguen, Nicolas

2011-10-01

Numerous studies have shown that men overestimate the sexual intent of women based on their clothing style; however, this hypothesis has not been assessed empirically in a natural setting. This small field study measured the time it took for men to approach two female confederates sitting in a tavern, one wearing suggestive clothes and one wearing more conservative clothes. The behavior of 108 men was observed over 54 periods on 16 different nights in two different taverns. The time it took for the men to approach after initial eye contact was significantly shorter in the suggestive clothing condition. The men were also asked by male confederates to rate the likelihood of having a date with the women, and having sex on the first date. The men rated their chances to have a date and to have sex significantly higher in the suggestive clothing condition. Results are discussed with respect to men's possible misinterpretation that women's clothing indicates sexual interest, and the risks associated with the misinterpretation.

Short-range precipitation forecasts using assimilation of simulated satellite water vapor profiles and column cloud liquid water amounts

NASA Technical Reports Server (NTRS)

Wu, Xiaohua; Diak, George R.; Hayden, Cristopher M.; Young, John A.

1995-01-01

These observing system simulation experiments investigate the assimilation of satellite-observed water vapor and cloud liquid water data in the initialization of a limited-area primitive equations model with the goal of improving short-range precipitation forecasts. The assimilation procedure presented includes two aspects: specification of an initial cloud liquid water vertical distribution and diabatic initialization. The satellite data is simulated for the next generation of polar-orbiting satellite instruments, the Advanced Microwave Sounding Unit (AMSU) and the High-Resolution Infrared Sounder (HIRS), which are scheduled to be launched on the NOAA-K satellite in the mid-1990s. Based on cloud-top height and total column cloud liquid water amounts simulated for satellite data a diagnostic method is used to specify an initial cloud water vertical distribution and to modify the initial moisture distribution in cloudy areas. Using a diabatic initialization procedure, the associated latent heating profiles are directly assimilated into the numerical model. The initial heating is estimated by time averaging the latent heat release from convective and large-scale condensation during the early forecast stage after insertion of satellite-observed temperature, water vapor, and cloud water formation. The assimilation of satellite-observed moisture and cloud water, together withy three-mode diabatic initialization, significantly alleviates the model precipitation spinup problem, especially in the first 3 h of the forecast. Experimental forecasts indicate that the impact of satellite-observed temperature and water vapor profiles and cloud water alone in the initialization procedure shortens the spinup time for precipitation rates by 1-2 h and for regeneration of the areal coverage by 3 h. The diabatic initialization further reduces the precipitation spinup time (compared to adiabatic initialization) by 1 h.

Ozone adsorption on carbon nanoparticles

NASA Astrophysics Data System (ADS)

Chassard, Guillaume; Gosselin, Sylvie; Visez, Nicolas; Petitprez, Denis

2014-05-01

Carbonaceous particles produced by incomplete combustion or thermal decomposition of hydrocarbons are ubiquitous in the atmosphere. On these particles are adsorbed hundreds of chemical species. Those of great concern to health are polycyclic aromatic hydrocarbons (PAHs). During atmospheric transport, particulate PAHs react with gaseous oxidants. The induced chemical transformations may change toxicity and hygroscopicity of these potentially inhalable particles. The interaction between ozone and carbon particles has been extensively investigated in literature. However ozone adsorption and surface reaction mechanisms are still ambiguous. Some studies described a fast catalytic decomposition of ozone initiated by an atomic oxygen chemisorption followed by a molecular oxygen release [1-3]. Others suggested a reversible ozone adsorption according to Langmuir-type behaviour [4,5]. The aim of this present study is a better understanding of ozone interaction with carbon surfaces. An aerosol of carbon nanoparticles was generated by flowing synthetic air in a glass tube containing pure carbon (primary particles < 50 nm), under magnetic stirring. The aerosol was then mixed with ozone in an aerosol flow tube. Ozone uptake experiments were performed with different particles concentrations with a fixed ozone concentration. The influence of several factors on kinetics was examined: initial ozone concentration, particle size (50 nm ≤ Dp ≤ 200 nm) and competitive adsorption (with probe molecule and water). The effect of initial ozone concentration was first studied. Accordingly to literature, it has been observed that the number of gas-phase ozone molecules lost per unit particle surface area tends towards a plateau for high ozone concentration suggesting a reversible ozone adsorption according to a Langmuir mechanism. We calculated the initial reaction probability between O3 and carbon particles.An initial uptake coefficient of 1.10-4 was obtained. Similar experiments were realized by selecting the particles size with a differential mobility analyser. We observed a strong size-dependent increase in reactivity with the decrease of particles size. This result is relevant for the health issues. Indeed the smallest particles are most likely to penetrate deep into the lungs. Competitive reactions between ozone and other species like H2O or atomic oxygen were also considered. Oxygen atoms were generated by photolysis of O3 (or O2) and were chosen because it is believed to form the same reactive oxygen intermediates than ozone. A weak water physisorption on soot was observed revealing hydrophobic properties of particles. Oxygen atoms were found to be strongly reactive. A Langmuir behavior was observed for oxygen atoms adsorption on carbon particles and we were able to determine an initial uptake coefficient of approximately 2.10-2. [1] Fenidel, W., et al., Interaction between carbon or iron aerosol particles and ozone. Atmospheric Environment, 1995. 29(9): p. 967-973. [2] Smith, D. and A. Chughtai, Reaction kinetics of ozone at low concentrations with n-hexane soot. Journal of geophysical research, 1996. 101(D14): p. 19607-19,620. [3] Kamm, S., et al., The heterogeneous reaction of ozone with soot aerosol. Atmospheric Environment, 1999. 33(28): p. 4651-4661. [4] Stephens, S., M.J. Rossi, and D.M. Golden, The heterogeneous reaction of ozone on carbonaceous surfaces. International journal of chemical kinetics, 1986. 18(10): p. 1133-1149. [5] Pöschl, U., et al., Interaction of ozone and water vapor with spark discharge soot aerosol particles coated with benzo [a] pyrene: O3 and H2O adsorption, benzo [a] pyrene degradation, and atmospheric implications. The Journal of Physical Chemistry A, 2001. 105(16): p. 4029-4041.

"Lies, damned lies ..." and observational studies in comparative effectiveness research.

PubMed

Albert, Richard K

2013-06-01

A new federal initiative has allocated $1.1 billion to comparative effectiveness research, and many have emphasized the importance of including observational studies in this effort. The rationale for using observational studies to assess comparative effectiveness is based on concerns that randomized controlled trials (RCTs) are not "real world" because they enroll homogeneous patient populations, measure study outcomes that are not important to patients, use protocols that are overly complex, are conducted in specialized centers, and use study treatments that are not consistent with usual care, and that RCTs are not always feasible because of a lack of equipoise, the need to assess delayed endpoints, and concerns that they take years to complete and are expensive. This essay questions the validity of each of these proposed limitations, summarizes concerns raised about the accuracy of results generated by observational studies, provides some examples of discrepancies between results of observational studies and RCTs that pertain to pulmonary and critical care, and suggests that using observational studies for comparative effectiveness research may increase rather than decrease the cost of health care and may harm patients.

Bedform response to flow variability

USGS Publications Warehouse

Nelson, J.M.; Logan, B.L.; Kinzel, P.J.; Shimizu, Y.; Giri, S.; Shreve, R.L.; McLean, S.R.

2011-01-01

Laboratory observations and computational results for the response of bedform fields to rapid variations in discharge are compared and discussed. The simple case considered here begins with a relatively low discharge over a flat bed on which bedforms are initiated, followed by a short high-flow period with double the original discharge, during which the morphology of the bedforms adjusts, followed in turn by a relatively long period of the original low discharge. For the grain size and hydraulic conditions selected, the Froude number remains subcritical during the experiment, and sediment moves predominantly as bedload. Observations show rapid development of quasi-two-dimensional bedforms during the initial period of low flow with increasing wavelength and height over the initial low-flow period. When the flow increases, the bedforms rapidly increase in wavelength and height, as expected from other empirical results. When the flow decreases back to the original discharge, the height of the bedforms quickly decreases in response, but the wavelength decreases much more slowly. Computational results using an unsteady two-dimensional flow model coupled to a disequilibrium bedload transport model for the same conditions simulate the formation and initial growth of the bedforms fairly accurately and also predict an increase in dimensions during the high-flow period. However, the computational model predicts a much slower rate of wavelength increase, and also performs less accurately during the final low-flow period, where the wavelength remains essentially constant, rather than decreasing. In addition, the numerical results show less variability in bedform wavelength and height than the measured values; the bedform shape is also somewhat different. Based on observations, these discrepancies may result from the simplified model for sediment particle step lengths used in the computational approach. Experiments show that the particle step length varies spatially and temporally over the bedforms during the evolution process. Assuming a constant value for the step length neglects the role of flow alterations in the bedload sediment-transport process, which appears to result in predicted bedform wavelength changes smaller than those observed. However, observations also suggest that three-dimensional effects play at least some role in the decrease of bedform wavelength, so incorporating better models for particle hop lengths alone may not be sufficient to improve model predictions. ?? 2011 John Wiley & Sons, Ltd.

The function of the RNA-binding protein TEL1 in moss reveals ancient regulatory mechanisms of shoot development.

PubMed

Vivancos, Julien; Spinner, Lara; Mazubert, Christelle; Charlot, Florence; Paquet, Nicolas; Thareau, Vincent; Dron, Michel; Nogué, Fabien; Charon, Céline

2012-03-01

The shoot represents the basic body plan in land plants. It consists of a repeated structure composed of stems and leaves. Whereas vascular plants generate a shoot in their diploid phase, non-vascular plants such as mosses form a shoot (called the gametophore) in their haploid generation. The evolution of regulatory mechanisms or genetic networks used in the development of these two kinds of shoots is unclear. TERMINAL EAR1-like genes have been involved in diploid shoot development in vascular plants. Here, we show that disruption of PpTEL1 from the moss Physcomitrella patens, causes reduced protonema growth and gametophore initiation, as well as defects in gametophore development. Leafy shoots formed on ΔTEL1 mutants exhibit shorter stems with more leaves per shoot, suggesting an accelerated leaf initiation (shortened plastochron), a phenotype shared with the Poaceae vascular plants TE1 and PLA2/LHD2 mutants. Moreover, the positive correlation between plastochron length and leaf size observed in ΔTEL1 mutants suggests a conserved compensatory mechanism correlating leaf growth and leaf initiation rate that would minimize overall changes in plant biomass. The RNA-binding protein encoded by PpTEL1 contains two N-terminus RNA-recognition motifs, and a third C-terminus non-canonical RRM, specific to TEL proteins. Removal of the PpTEL1 C-terminus (including this third RRM) or only 16-18 amino acids within it seriously impairs PpTEL1 function, suggesting a critical role for this third RRM. These results show a conserved function of the RNA-binding PpTEL1 protein in the regulation of shoot development, from early ancestors to vascular plants, that depends on the third TEL-specific RRM.

Patient radiation doses in interventional cardiology in the U.S.: Advisory data sets and possible initial values for U.S. reference levels

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

Miller, Donald L.; Hilohi, C. Michael; Spelic, David C.

2012-10-15

Purpose: To determine patient radiation doses from interventional cardiology procedures in the U.S and to suggest possible initial values for U.S. benchmarks for patient radiation dose from selected interventional cardiology procedures [fluoroscopically guided diagnostic cardiac catheterization and percutaneous coronary intervention (PCI)]. Methods: Patient radiation dose metrics were derived from analysis of data from the 2008 to 2009 Nationwide Evaluation of X-ray Trends (NEXT) survey of cardiac catheterization. This analysis used deidentified data and did not require review by an IRB. Data from 171 facilities in 30 states were analyzed. The distributions (percentiles) of radiation dose metrics were determined for diagnosticmore » cardiac catheterizations, PCI, and combined diagnostic and PCI procedures. Confidence intervals for these dose distributions were determined using bootstrap resampling. Results: Percentile distributions (advisory data sets) and possible preliminary U.S. reference levels (based on the 75th percentile of the dose distributions) are provided for cumulative air kerma at the reference point (K{sub a,r}), cumulative air kerma-area product (P{sub KA}), fluoroscopy time, and number of cine runs. Dose distributions are sufficiently detailed to permit dose audits as described in National Council on Radiation Protection and Measurements Report No. 168. Fluoroscopy times are consistent with those observed in European studies, but P{sub KA} is higher in the U.S. Conclusions: Sufficient data exist to suggest possible initial benchmarks for patient radiation dose for certain interventional cardiology procedures in the U.S. Our data suggest that patient radiation dose in these procedures is not optimized in U.S. practice.« less

Qualitative Assessment of Soil Carbon in a Rehabilitated Forest Using Fourier Transform Infrared Spectroscopy

PubMed Central

Ch'ng, Huck-Ywih; Ahmed, Osumanu Haruna; Ab. Majid, Nik Muhamad

2011-01-01

Logging and poor shifting cultivation negatively affect initial soil carbon (C) storage, especially at the initial stage of deforestation, as these practices lead to global warming. As a result, an afforestation program is needed to mitigate this problem. This study assessed initial soil C buildup of rehabilitated forests using Fourier transform infrared (FTIR) spectroscopy. The relatively high E4/E6 values of humic acids (HAs) in the rehabilitated forest indicate prominence of aliphatic components, suggesting that the HAs were of low molecular weight. The total acidity, carboxylic (-COOH) and phenolic (-OH) of the rehabilitated forest were found to be consistent with the ranges reported by other researchers. The spectra of all locations were similar because there was no significant difference in the quantities of C in humic acids (CHA) regardless of forest age and soil depth. The spectra showed distinct absorbance at 3290, 1720, 1630, 1510, 1460, 1380, and 1270 cm-1. Increase of band at 1630 and 1510 cm-1 from 0–20 to 40–60 cm were observed, suggesting C buildup from the lowest depths 20–40 and 40–60 cm. However, the CHA content in the soil depths was not different. The band at 1630 cm-1 was assigned to carboxylic and aromatic groups. Increase in peak intensity at 1510 cm-1 was because C/N ratio increased with increasing soil depth. This indicates that decomposition rate decreased with increasing soil depth and decreased with CHA. The finding suggests that FTIR spectroscopy enables the assessment of C composition functional group buildup at different depths and ages. PMID:21403973

High Diversity, Low Disparity and Small Body Size in Plesiosaurs (Reptilia, Sauropterygia) from the Triassic–Jurassic Boundary

PubMed Central

Benson, Roger B. J.; Evans, Mark; Druckenmiller, Patrick S.

2012-01-01

Invasion of the open ocean by tetrapods represents a major evolutionary transition that occurred independently in cetaceans, mosasauroids, chelonioids (sea turtles), ichthyosaurs and plesiosaurs. Plesiosaurian reptiles invaded pelagic ocean environments immediately following the Late Triassic extinctions. This diversification is recorded by three intensively-sampled European fossil faunas, spanning 20 million years (Ma). These provide an unparalleled opportunity to document changes in key macroevolutionary parameters associated with secondary adaptation to pelagic life in tetrapods. A comprehensive assessment focuses on the oldest fauna, from the Blue Lias Formation of Street, and nearby localities, in Somerset, UK (Earliest Jurassic: 200 Ma), identifying three new species representing two small-bodied rhomaleosaurids (Stratesaurus taylori gen et sp. nov.; Avalonnectes arturi gen. et sp. nov) and the most basal plesiosauroid, Eoplesiosaurus antiquior gen. et sp. nov. The initial radiation of plesiosaurs was characterised by high, but short-lived, diversity of an archaic clade, Rhomaleosauridae. Representatives of this initial radiation were replaced by derived, neoplesiosaurian plesiosaurs at small-medium body sizes during a more gradual accumulation of morphological disparity. This gradualistic modality suggests that adaptive radiations within tetrapod subclades are not always characterised by the initially high levels of disparity observed in the Paleozoic origins of major metazoan body plans, or in the origin of tetrapods. High rhomaleosaurid diversity immediately following the Triassic-Jurassic boundary supports the gradual model of Late Triassic extinctions, mostly predating the boundary itself. Increase in both maximum and minimum body length early in plesiosaurian history suggests a driven evolutionary trend. However, Maximum-likelihood models suggest only passive expansion into higher body size categories. PMID:22438869

Borehole Breakout Growth and In-Situ Stress Orientation in the Central Scandinavian Caledonides: Results from the Cosc-1 Borehole

NASA Astrophysics Data System (ADS)

Wenning, Q.; Zappone, A.; Berthet, T.; Ask, M. V. S.; Rosberg, J. E.; Almqvist, B. S. G.

2017-12-01

Borehole breakouts are often assumed to form near instantaneously due to stress perturbations around boreholes after the rock mass was removed. Recent observations in sediments [e.g., Moore et al., 2011] and crystalline rocks [e.g., Berard and Cornet, 2003], as well as numerical modelling results [e.g., Schoenball et al., 2014], suggest that there are cases in which borehole breakout grows radially over time, forcing us to reconsider subsurface stress estimation. These observations are rare due to drilling difficulties (i.e., cementing and casing the borehole after drilling), often only allowing a single image logging campaign. In 2014, the Collisional Orogeny in the Scandinavian Caledonides deep scientific borehole (COSC-1) was drilled to a depth of 2.5 km. To date the borehole is open and uncased, allowing two acoustic televiewer logging campaigns, with more than one year between campaigns. The borehole is still available for supplementary data collactions. These logs provide detailed images along the full length of the 2.5 km deep borehole with 1.6 km of overlapping logs for breakout and drilling induced tensile fracture analysis. The results show from the sparse occurrence of breakouts and drilling induced tensile fractures a NW-SE average maximum horizontal stress direction, consistent with the general trend in Scandinavia. The unique acquisition of image logs in two successions allows for analysis of time-dependent borehole deformation, indicating that six breakout zones have crept, both along the borehole axis and radially (up to 20° growth) around the borehole. While some breakouts have grown, the formation of new breakouts has not occurred. The occurrence of breakouts and their growth appear to be independent of lithology. The observed growth after the second logging campaign suggests that under conditions where the stress exceeded the strength of the rock, the resulting breakout causes perturbations in the stresses around the borehole in the near vicinity. As those stresses are redistributed around the breakouts over the course of the year, the breakouts widen. The fact that no new breakout zones have formed suggests that the brittle creeping is not likely to initiate breakouts and that an initial perturbation during drilling (i.e., a breakout) is required to observe such a phenomenon.

Characteristics of 3-D transport simulations of the stratosphere and mesosphere

NASA Technical Reports Server (NTRS)

Fairlie, T. D. A.; Siskind, D. E.; Turner, R. E.; Fisher, M.

1992-01-01

A 3D mechanistic, primitive-equation model of the stratosphere and mesosphere is coupled to an offline spectral transport model. The dynamics model is initialized with and forced by observations so that the coupled models may be used to study specific episodes. Results are compared with those obtained by transport online in the dynamics model. Although some differences are apparent, the results suggest that coupling of the models to a comprehensive photochemical package will provide a useful tool for studying the evolution of constituents in the middle atmosphere during specific episodes.

Inclusion-Body Myositis Associated with Alzheimer's Disease

PubMed Central

Levacic, Danijela; Peddareddygari, Leema Reddy; Nochlin, David; Sharer, Leroy R.; Grewal, Raji P.

2013-01-01

Sporadic inclusion-body myositis (s-IBM) is a myopathy that is characterized by progressive weakness and muscle pathology demonstrating inflammation and rimmed vacuoles. In addition, similar to the pathology observed in the brains of patients with Alzheimer's disease, the deposition of beta-amyloid and phosphorylated tau proteins in muscle fibers has been reported. These shared pathologic features have prompted hypotheses suggesting a shared etiology of these two conditions. We report a case of a 73-year-old woman initially diagnosed with s-IBM who later developed Alzheimer's disease. PMID:23606855

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

Lebrilla, C.B.; Schulze, C.; Schwarz, H.

The gas-phase reaction of bare Fe/sup +/ atoms with linear alkyl nitriles generates end-on complexes which, depending on geometrical constraints, specifically interact with remote C-H bonds. Based on chain length effect studies and the investigation of labeled precursors, a mechanism is suggested which accounts for the chemospecificity observed for the loss of H/sub 2/ and C/sub 2/H/sub 4/ from RCN/Fe/sup +/ complexes. This mechanism does not follow the analogous reaction of Fe/sup +/ with alkenes and alkynes but involves an initial C-H insertion of the remote CH bonds followed by a C-C insertion.

Hauntings and poltergeist-like episodes as a confluence of conventional phenomena: a general hypothesis.

PubMed

Houran, J; Lange, R

1996-12-01

Hauntings and poltergeist-like episodes are argued to be products of contagious reactions to ambiguous environmental or cognitive events. In particular, evidence suggests that the subjective and objective effects reported by percipients are the function of independent, nonparanoraml etiologies whose constitutions have been previously established and described. According to this multivariate model, the labeling of ambiguous events as "abnormal" or "paranormal" initiates the reactive process which is subsequently sustained by perceptual contagion, i.e., flurries of paranormal observations due self-reinforcing attentional processes.

[Legionnaires' disease: 21 cases observed over 2.5 years in a Parisian respiratory intensive care unit].

PubMed

Carette, M F; Mayaud, C; Dournon, E; Bure, A; Houacine, S; Morinière, B; Sicard, J F; Akoun, G

1985-01-01

The incidence of Legionnaire's disease is probably underestimated in France. Its clinical presentation is very suggestive, especially after the failure of a 48 hour therapeutic trial of beta-lactams, when a pneumococcal infection is initially suspected. This one sign is sufficient to orient the diagnostic survey and constitutes an indication for a therapeutic trial of macrolides for at least 72 hours. In fact, the delay in the diagnosis appears to be the determinant factor in the fatal outcome of the disease.

Protecting superconducting qubits from radiation

NASA Astrophysics Data System (ADS)

Córcoles, Antonio D.; Chow, Jerry M.; Gambetta, Jay M.; Rigetti, Chad; Rozen, J. R.; Keefe, George A.; Beth Rothwell, Mary; Ketchen, Mark B.; Steffen, M.

2011-10-01

We characterize a superconducting qubit before and after embedding it along with its package in an absorptive medium. We observe a drastic improvement in the effective qubit temperature and over a tenfold improvement in the relaxation time up to 5.7 μs. Our results suggest the presence of external radiation inside the cryogenic apparatus can be a limiting factor for both qubit initialization and coherence. Calculations support the hypothesis that the relaxation is not limited by direct coupling of thermal photons to the qubit prior to embedding, but by dissipation arising from quasiparticle generation.

Interaction of Two Slip Planes on Extrusion Growth in Fatigue Band

DTIC Science & Technology

1987-01-01

observed under microscope in fatigue specimens as indicated by Essmann et al . [23] and Mughrabi [24]. t I 1 It I I 3 @ O.OS^ = 0 1S^ lAlONG SUP... Mughrabi , et. al . [25] have suggested a model of dislocation dipoles in a single crystal as shown in Fig. 2. The initial inelastic strain e^„ due to the...interesting question which was raised by Mughrabi , and Essmann et. al . [23] was, after the extrusion has reached the amount of static extrusion , will

Polar distribution of annexin-like proteins during phytochrome-mediated initiation and growth of rhizoids in the ferns Dryopteris and Anemia

NASA Technical Reports Server (NTRS)

Clark, G. B.; Turnwald, S.; Tirlapur, U. K.; Haas, C. J.; von der Mark, K.; Roux, S. J.; Scheuerlein, R.

1995-01-01

Although the calcium requirement of phytochrome-mediated fern spore germination and early rhizoid growth is well established, the calcium-binding proteins that serve as transducers for these responses are not known. Here we report the presence of annexin-like proteins in germinating spores of Dryopteris filix-mas (L.) Schott and Anemia phyllitidis (L.) Sw. and evidence that they may be important participants in early photomorphogenic changes in gametophytes. Immunolocalization and immunoblot assays of these proteins were carried out using polyclonal antibodies raised either against a 35-kDa annexin-like protein from pea or against anchorin CII from chicken. Western-blot analysis showed that crude protein extracts obtained from both species after red-light treatment contained two cross-reactive protein bands with molecular weights around 70 kDa. These proteins were annexin-like in that they bound to a phosphatidylserine affinity column in a calcium-dependent fashion. Using this column, two protein bands around 70 kDa, i.e. 67 and 73 kDa, were partially purified together with proteins at 36 kDa and a doublet at 54 kDa. Proteins of these latter molecular weights are suggested to be members of the annexin family, but no cross-reactivity could be found between these and the two antibodies used in our investigations. Immunodetectable levels of these proteins were observed only after light-mediated induction of spore germination. Imaging of the immuno-localization patterns observed with both antibodies showed that the annexin-like proteins are concentrated at the extreme tips of the rhizoids in D. filix-mas and A. phyllitidis during rhizoid initiation and all stages of elongation. We suggest that these proteins may play a major role in the tip-oriented exocytosis events that are critical for the initiation and growth of fern rhizoids.

Compensation patterns for healthcare workers in British Columbia, Canada.

PubMed

Alamgir, H; Siow, S; Yu, S; Ngan, K; Guzman, J

2009-06-01

This report examines relationships between the acceptance of compensation claims, and employee and workplace characteristics for healthcare workers in British Columbia, Canada to determine suitability of using only accepted claims for occupational epidemiology research. A retrospective cohort of full-time healthcare workers was constructed from an active incident surveillance database. Incidents filed for compensation over a 1-year period were examined for initial claim decision within a 6-month window relative to sub-sector of employment, age, sex, seniority, occupation of workers, and injury category. Compensation costs and duration of time lost for initially accepted claims were also investigated. Multiple logistic regression models with generalised estimating equations (GEEs) were used to calculate adjusted relative odds (ARO) of claims decision accounting for confounding factors and clustering effects. Employees of three health regions in British Columbia filed 2274 work-related claims in a year, of which 1863 (82%) were initially accepted for compensation. Proportion of claims accepted was lowest in community care (79%) and corporate office settings (79%) and highest in long-term care settings (86%). Overall, 46% of claims resulting from allergy/irritation were accepted, in contrast to 98% acceptance of claims from cuts and puncture wounds. Licensed practical nurses had the lowest odds of claims not accepted compared with registered nurses (ARO (95% CI) = 0.55 (0.33 to 0.91)), whereas management/administrative staff had the highest odds (ARO = 2.91 (1.25 to 6.79)) of claims not accepted. A trend was observed with higher seniority of workers associated with lower odds of non-acceptance of claims. Analysis from British Columbia's healthcare sector suggests variation in workers' compensation acceptance exists across sub-sectors, occupations, seniority of workers, and injury categories. The patterns observed, however, were independent of age and sex of workers. Results suggest that when using workers' compensation datasets, local adjudication regulations and factors associated with acceptance of claims should be taken into consideration.

Polar distribution of annexin-like proteins during phytochrome-mediated initiation and growth of rhizoids in the ferns Dryopteris and Anemia.

PubMed

Clark, G B; Turnwald, S; Tirlapur, U K; Haas, C J; von der Mark, K; Roux, S J; Scheuerlein, R

1995-01-01

Although the calcium requirement of phytochrome-mediated fern spore germination and early rhizoid growth is well established, the calcium-binding proteins that serve as transducers for these responses are not known. Here we report the presence of annexin-like proteins in germinating spores of Dryopteris filix-mas (L.) Schott and Anemia phyllitidis (L.) Sw. and evidence that they may be important participants in early photomorphogenic changes in gametophytes. Immunolocalization and immunoblot assays of these proteins were carried out using polyclonal antibodies raised either against a 35-kDa annexin-like protein from pea or against anchorin CII from chicken. Western-blot analysis showed that crude protein extracts obtained from both species after red-light treatment contained two cross-reactive protein bands with molecular weights around 70 kDa. These proteins were annexin-like in that they bound to a phosphatidylserine affinity column in a calcium-dependent fashion. Using this column, two protein bands around 70 kDa, i.e. 67 and 73 kDa, were partially purified together with proteins at 36 kDa and a doublet at 54 kDa. Proteins of these latter molecular weights are suggested to be members of the annexin family, but no cross-reactivity could be found between these and the two antibodies used in our investigations. Immunodetectable levels of these proteins were observed only after light-mediated induction of spore germination. Imaging of the immuno-localization patterns observed with both antibodies showed that the annexin-like proteins are concentrated at the extreme tips of the rhizoids in D. filix-mas and A. phyllitidis during rhizoid initiation and all stages of elongation. We suggest that these proteins may play a major role in the tip-oriented exocytosis events that are critical for the initiation and growth of fern rhizoids.

Wheat DNA Primase (RNA Primer Synthesis in Vitro, Structural Studies by Photochemical Cross-Linking, and Modulation of Primase Activity by DNA Polymerases).

PubMed Central

Laquel, P.; Litvak, S.; Castroviejo, M.

1994-01-01

DNA primase synthesizes short RNA primers used by DNA polymerases to initiate DNA synthesis. Two proteins of approximately 60 and 50 kD were recognized by specific antibodies raised against yeast primase subunits, suggesting a high degree of analogy between wheat and yeast primase subunits. Gel-filtration chromatography of wheat primase showed two active forms of 60 and 110 to 120 kD. Ultraviolet-induced cross-linking with radioactive oligothymidilate revealed a highly labeled protein of 60 kD. After limited trypsin digestion of wheat (Triticum aestivum L.) primase, a major band of 48 kD and two minor bands of 38 and 17 kD were observed. In the absence of DNA polymerases, the purified primase synthesizes long RNA products. The size of the RNA product synthesized by wheat primase is considerably reduced by the presence of DNA polymerases, suggesting a modulatory effect of the association between these two enzymes. Lowering the primase concentration in the assay also favored short RNA primer synthesis. Several properties of the wheat DNA primase using oligoadenylate [oligo(rA)]-primed or unprimed polythymidilate templates were studied. The ability of wheat primase, without DNA polymerases, to elongate an oligo(rA) primer to long RNA products depends on the primer size, temperature, and the divalent cation concentration. Thus, Mn2+ ions led to long RNA products in a very wide range of concentrations, whereas with Mg2+ long products were observed around 15 mM. We studied the ability of purified wheat DNA polymerases to initiate DNA synthesis from an RNA primer: wheat DNA polymerase A showed the highest activity, followed by DNA polymerases B and CII, whereas DNA polymerase CI was unable to initiate DNA synthesis from an RNA primer. Results are discussed in terms of understanding the role of these polymerases in DNA replication in plants. PMID:12232187

Probing the end of reionization with the near zones of z ≳ 6 QSOs

NASA Astrophysics Data System (ADS)

Keating, Laura C.; Haehnelt, Martin G.; Cantalupo, Sebastiano; Puchwein, Ewald

2015-11-01

QSO near zones are an important probe of the ionization state of the intergalactic medium (IGM) at z ˜ 6-7, at the end of reionization. We present here high-resolution cosmological 3D radiative transfer simulations of QSO environments for a wide range of host halo masses, 1010-12.5 M⊙. Our simulated near zones reproduce both the overall decrease of observed near-zone sizes at 6 < z < 7 and their scatter. The observable near-zone properties in our simulations depend only very weakly on the mass of the host halo. The size of the H II region expanding into the IGM is generally limited by (super-)Lyman Limit systems loosely associated with (low-mass) dark matter haloes. This leads to a strong dependence of near-zone size on direction and drives the large observed scatter. In the simulation centred on our most massive host halo, many sightlines show strong red damping wings even for initial volume averaged neutral hydrogen fractions as low as ˜10-3. For QSO lifetimes long enough to allow growth of the central supermassive black hole while optically bright, we can reproduce the observed near zone of ULAS J1120+0641 only with an IGM that is initially neutral. Our results suggest that larger samples of z > 7 QSOs will provide important constraints on the evolution of the neutral hydrogen fraction and thus on how late reionization ends.

SIM PlanetQuest Key Project Precursor Observations to Detect Gas Giant Planets Around Young Stars

NASA Technical Reports Server (NTRS)

Tanner, Angelle; Beichman, Charles; Akeson, Rachel; Ghez, Andrea; Grankin, Konstantin N.; Herbst, William; Hillenbrand, Lynne; Huerta, Marcos; Konopacky, Quinn; Metchev, Stanimir;

Wildfire-related debris-flow initiation processes, Storm King Mountain, Colorado

USGS Publications Warehouse

Cannon, S.H.; Kirkham, R.M.; Parise, M.

2001-01-01

A torrential rainstorm on September 1, 1994 at the recently burned hillslopes of Storm King Mountain, CO, resulted in the generation of debris flows from every burned drainage basin. Maps (1:5000 scale) of bedrock and surficial materials and of the debris-flow paths, coupled with a 10-m Digital Elevation Model (DEM) of topography, are used to evaluate the processes that generated fire-related debris flows in this setting. These evaluations form the basis for a descriptive model for fire-related debris-flow initiation. The prominent paths left by the debris flows originated in 0- and 1st-order hollows or channels. Discrete soil-slip scars do not occur at the heads of these paths. Although 58 soil-slip scars were mapped on hillslopes in the burned basins, material derived from these soil slips accounted for only about 7% of the total volume of material deposited at canyon mouths. This fact, combined with observations of significant erosion of hillslope materials, suggests that a runoff-dominated process of progressive sediment entrainment by surface runoff, rather than infiltration-triggered failure of discrete soil slips, was the primary mechanism of debris-flow initiation. A paucity of channel incision, along with observations of extensive hillslope erosion, indicates that a significant proportion of material in the debris flows was derived from the hillslopes, with a smaller contribution from the channels. Because of the importance of runoff-dominated rather than infiltration-dominated processes in the generation of these fire-related debris flows, the runoff-contributing area that extends upslope from the point of debris-flow initiation to the drainage divide, and its gradient, becomes a critical constraint in debris-flow initiation. Slope-area thresholds for fire-related debris-flow initiation from Storm King Mountain are defined by functions of the form Acr(tan ??)3 = S, where Acr is the critical area extending upslope from the initiation location to the drainage divide, and tan ?? is its gradient. The thresholds vary with different materials. ?? 2001 Elsevier Science B.V. All rights reserved.

Formation and stability of a double subduction system: a numerical study

NASA Astrophysics Data System (ADS)

Pusok, A. E.; Stegman, D. R.

2017-12-01

Examples of double subduction systems can be found in both modern (Izu-Bonin-Marianas and Ryukyu arcs, e.g. Hall [1997]) and ancient (Kohistan arc in Western Himalayas, e.g. Burg et al. [2006]) tectonic record. A double subduction system has been proposed to explain the high convergence rate observed for the India-Eurasia convergence [Aitchison et al., 2000, Jagoutz et al., 2015; Holt et al., 2017]. Rates of convergence across coupled double subduction systems can be significantly faster than across single subduction systems because of slab pull by two slabs. However, despite significant geological and geophysical observations, questions regarding double subduction remain largely unexplored. For example, it is unclear how a double subduction system forms and remains stable over millions of years. Previous numerical studies of double subduction either introduced weak zones to initiate subduction [Mishin et al., 2008] or both the subduction systems were already initiated [Jagoutz et al., 2015, Holt et al., 2017], thus assuming a priori information regarding the initial position of the two subduction zones. Moreover, the driving forces initiating a stable double subduction system remain unclear. In the context of India-Eurasia, Cande and Stegman [2011] found evidence the Reunion mantle plume head provided an ephemeral driving force on both the Indian and African plates for as long as 25 Million years, and had significant influence on plate boundaries in the region. In this study, we perform 2D and 3D numerical simulations using the code LaMEM [Kaus et al., 2016] to investigate i) subduction initiation of a secondary system in an already initiated single subduction system, and ii) the dynamics and stability of the newly formed double subduction system. We start from a single subduction setup, where subduction is already initiated (mature) and we stress the system by controlling the convergence rate of the system (i.e. imposing influx/outflux boundary conditions). Under certain conditions, a second subduction may develop and transform into a stable double subduction system. Results suggest that the fate of the incipient secondary subduction depends on internal factors (i.e. buoyancy and rheology), but also on the dynamics of the primary subduction zone and the boundary conditions (i.e. convergence rate).

Electron dropout echoes induced by interplanetary shock: Van Allen Probes observations

DOE PAGES

Hao, Y. X.; Zong, Q. -G.; Zhou, X. -Z.; ...

2016-06-07

On 23 November 2012, a sudden dropout of the relativistic electron flux was observed after an interplanetary shock arrival. The dropout peaks at ~1 MeV and more than 80% of the electrons disappeared from the drift shell. Van Allen twin Probes observed a sharp electron flux dropout with clear energy dispersion signals. The repeating flux dropout and recovery signatures, or “dropout echoes”, constitute a new phenomenon referred to as a “drifting electron dropout” with a limited initial spatial range. The azimuthal range of the dropout is estimated to be on the duskside, from ~1300 to 0100 LT. We then concludemore » that the shock-induced electron dropout is not caused by the magnetopause shadowing. Furthermore, the dropout and consequent echoes suggest that the radial migration of relativistic electrons is induced by the strong dusk-dawn asymmetric interplanetary shock compression on the magnetosphere.« less

Empirical Storm-Time Correction to the International Reference Ionosphere Model E-Region Electron and Ion Density Parameterizations Using Observations from TIMED/SABER

NASA Technical Reports Server (NTRS)

Mertens, Christoper J.; Winick, Jeremy R.; Russell, James M., III; Mlynczak, Martin G.; Evans, David S.; Bilitza, Dieter; Xu, Xiaojing

2007-01-01

The response of the ionospheric E-region to solar-geomagnetic storms can be characterized using observations of infrared 4.3 micrometers emission. In particular, we utilize nighttime TIMED/SABER measurements of broadband 4.3 micrometers limb emission and derive a new data product, the NO+(v) volume emission rate, which is our primary observation-based quantity for developing an empirical storm-time correction the IRI E-region electron density. In this paper we describe our E-region proxy and outline our strategy for developing the empirical storm model. In our initial studies, we analyzed a six day storm period during the Halloween 2003 event. The results of this analysis are promising and suggest that the ap-index is a viable candidate to use as a magnetic driver for our model.

Estimating monthly streamflow values by cokriging

USGS Publications Warehouse

Solow, A.R.; Gorelick, S.M.

1986-01-01

Cokriging is applied to estimation of missing monthly streamflow values in three records from gaging stations in west central Virginia. Missing values are estimated from optimal consideration of the pattern of auto- and cross-correlation among standardized residual log-flow records. Investigation of the sensitivity of estimation to data configuration showed that when observations are available within two months of a missing value, estimation is improved by accounting for correlation. Concurrent and lag-one observations tend to screen the influence of other available observations. Three models of covariance structure in residual log-flow records are compared using cross-validation. Models differ in how much monthly variation they allow in covariance. Precision of estimation, reflected in mean squared error (MSE), proved to be insensitive to this choice. Cross-validation is suggested as a tool for choosing an inverse transformation when an initial nonlinear transformation is applied to flow values. ?? 1986 Plenum Publishing Corporation.

Direct observation of TALE protein dynamics reveals a two-state search mechanism

PubMed Central

Cuculis, Luke; Abil, Zhanar; Zhao, Huimin; Schroeder, Charles M.

2015-01-01

Transcription activator-like effector (TALE) proteins are a class of programmable DNA-binding proteins for which the fundamental mechanisms governing the search process are not fully understood. Here we use single-molecule techniques to directly observe TALE search dynamics along DNA templates. We find that TALE proteins are capable of rapid diffusion along DNA using a combination of sliding and hopping behaviour, which suggests that the TALE search process is governed in part by facilitated diffusion. We also observe that TALE proteins exhibit two distinct modes of action during the search process—a search state and a recognition state—facilitated by different subdomains in monomeric TALE proteins. Using TALE truncation mutants, we further demonstrate that the N-terminal region of TALEs is required for the initial non-specific binding and subsequent rapid search along DNA, whereas the central repeat domain is required for transitioning into the site-specific recognition state. PMID:26027871

Direct observation of TALE protein dynamics reveals a two-state search mechanism.

PubMed

Cuculis, Luke; Abil, Zhanar; Zhao, Huimin; Schroeder, Charles M

2015-06-01

Transcription activator-like effector (TALE) proteins are a class of programmable DNA-binding proteins for which the fundamental mechanisms governing the search process are not fully understood. Here we use single-molecule techniques to directly observe TALE search dynamics along DNA templates. We find that TALE proteins are capable of rapid diffusion along DNA using a combination of sliding and hopping behaviour, which suggests that the TALE search process is governed in part by facilitated diffusion. We also observe that TALE proteins exhibit two distinct modes of action during the search process-a search state and a recognition state-facilitated by different subdomains in monomeric TALE proteins. Using TALE truncation mutants, we further demonstrate that the N-terminal region of TALEs is required for the initial non-specific binding and subsequent rapid search along DNA, whereas the central repeat domain is required for transitioning into the site-specific recognition state.

A multiwavelength study of a double impulsive flare

NASA Technical Reports Server (NTRS)

Strong, K. T.; Benz, A. O.; Dennis, B. R.; Poland, A. I.; Leibacher, J. W.; Mewe, R.; Schrijver, J.; Simnett, G.; Smith, J. B., Jr.; Sylwester, J.

1984-01-01

Solar Maximum Mission (SMM) and ground-based observations are given for two flares which occurred 3 min apart in the same section of the active region. The physical characteristics of the two flares are derived and compared, and the main difference between them is noted to be in the preflare state of the coronal plasma at the flare site. These data suggest that the plasma filling the flaring loops absorbed most of the energy released during the impulsive phase of the second flare, so that only a fraction of the energy could reach the chromosphere to produce mass motions and turbulence. Since a study of the brightest flares observed by SMM shows that at least 43 percent of them are multiple, the situation presently studied may be quite common, and the difference in initial plasma conditions could explain at least some of the large variations in observed flare parameters.

An instrumental variable approach finds no associated harm or benefit from early dialysis initiation in the United States

PubMed Central

Scialla, Julia J.; Liu, Jiannong; Crews, Deidra C.; Guo, Haifeng; Bandeen-Roche, Karen; Ephraim, Patti L.; Tangri, Navdeep; Sozio, Stephen M.; Shafi, Tariq; Miskulin, Dana C.; Michels, Wieneke M.; Jaar, Bernard G.; Wu, Albert W.; Powe, Neil R.; Boulware, L. Ebony

2014-01-01

The estimated glomerular filtration rate (eGFR) at dialysis initiation has been rising. Observational studies suggest harm, but may be confounded by unmeasured factors. As instrumental variable methods may be less biased we performed a retrospective cohort study of 310,932 patients starting dialysis between 2006 to 2008 and registered in the United States Renal Data System in order to describe geographic variation in eGFR at dialysis initiation and determine its association with mortality. Patients were grouped into 804 health service areas by zip code. Individual eGFR at dialysis initiation averaged 10.8 ml/min/1.73m2 but varied geographically. Only 11% of the variation in mean health service areas-level eGFR at dialysis initiation was accounted for by patient characteristics. We calculated demographic-adjusted mean eGFR at dialysis initiation in the health service areas using the 2006 and 2007 incident cohort as our instrument and estimated the association between individual eGFR at dialysis initiation and mortality in the 2008 incident cohort using the 2 stage residual inclusion method. Among 89,547 patients starting dialysis in 2008 with eGFR 5 to 20 ml/min/1.73m2, eGFR at initiation was not associated with mortality over a median of 15.5 months [hazard ratio 1.025 per 1 ml/min/1.73m2 for eGFR 5 to 14 ml/min/1.73m2; and 0.973 per 1 ml/min/1.73m2 for eGFR 14 to 20 ml/min/1.73m2]. Thus, there was no associated harm or benefit from early dialysis initiation in the United States. PMID:24786707

Numerical Simulations of Lightcurves of Non-principal Axis Rotators

NASA Astrophysics Data System (ADS)

Mueller, Beatrice E. A.; Samarasinha, N. H.

2012-10-01

Theory predicts that most short-period comets should be in non-principal axis (NPA) rotational states (Jewitt 1997) due to torques caused by outgassing from the nuclei. However the fraction that is currently observed to be in such a state is small (less than 15%; Samarasinha et al 2004, and references therein). This suggests that NPA states naturally occurring as a consequence of cometary jetting are more rapidly damped because comets are structurally far weaker than has been assumed. However, there is a serious question whether this discrepancy is real or an artifact of interpreting lightcurve observations. We will present initial results of our numerical simulation of the observational manifestation of lightcurves over the range of possible NPA rotation states and determine the effects of observing geometry, signal-to-noise, and sampling. References: Jewitt, D. 1997. Cometary Rotation: An Overview. Earth, Moon, and Planets 79, 35-53. Samarasinha, N.H., B.E.A. Mueller, M.J.S. Belton,L. Jorda 2004. Rotation of Cometary Nuclei. In Comets II, pp. 281-299.

Bipolar cloud-to-ground lightning flash observations

NASA Astrophysics Data System (ADS)

Saba, Marcelo M. F.; Schumann, Carina; Warner, Tom A.; Helsdon, John H.; Schulz, Wolfgang; Orville, Richard E.

2013-10-01

lightning is usually defined as a lightning flash where the current waveform exhibits a polarity reversal. There are very few reported cases of cloud-to-ground (CG) bipolar flashes using only one channel in the literature. Reports on this type of bipolar flashes are not common due to the fact that in order to confirm that currents of both polarities follow the same channel to the ground, one necessarily needs video records. This study presents five clear observations of single-channel bipolar CG flashes. High-speed video and electric field measurement observations are used and analyzed. Based on the video images obtained and based on previous observations of positive CG flashes with high-speed cameras, we suggest that positive leader branches which do not participate in the initial return stroke of a positive cloud-to-ground flash later generate recoil leaders whose negative ends, upon reaching the branch point, traverse the return stroke channel path to the ground resulting in a subsequent return stroke of opposite polarity.

The Effect of Magnetic Fields on Gamma-Ray Bursts Inferred from Multi-Wavelength Observations of the Bursts of 23 January 1999

NASA Technical Reports Server (NTRS)

Galama, T. J.; Briggs, M. S.; Wijers, R. A. M. J.; Vreeswijk, P. M.; Rol, E.; Band, D.; vanParadijs, J.; Kouveliotou, C.; Preece, R. D.; Bremer, M.

1999-01-01

Gamma-ray bursts (GRBs) are thought to arise when an extremely relativistic outflow of particles from a massive explosion (the nature at which is still unclear) interacts with material surrounding the site of the explosion. Observations of the evolving changes in emission at many wavelengths allow us to investigate the origin of the photons, and so potentially determine the nature of the explosion. Here we report the results of gamma-ray, optical, infrared, submillimeter, millimeter and radio observations of the burst ORB990123 and its afterglow. Our interpretation of the data indicates that the initial and afterglow emissions are associated with three distinct regions in the fireball. The peak flux of the afterglow, one day after the burst, has a lower frequency than observed for other bursts; this explains the short-lived radio emission. We suggest that the differences between bursts reflect variations in the magnetic-field strength in the afterglow-emitting regions.

Mirror neuron activation of musicians and non-musicians in response to motion captured piano performances.

PubMed

Hou, Jiancheng; Rajmohan, Ravi; Fang, Dan; Kashfi, Karl; Al-Khalil, Kareem; Yang, James; Westney, William; Grund, Cynthia M; O'Boyle, Michael W

2017-07-01

Mirror neurons (MNs) activate when performing an action and when an observer witnesses the same action performed by another individual. Functional magnetic resonance imaging (fMRI) and presentation of motion captured piano performances were used to identify differences in MN activation for musicians/non-musicians when viewing piano pieces played in a "Correct" mode (i.e., emphasis on technical correctness) or an "Enjoyment" mode (i.e., simply told to "enjoy" playing the piece). Results showed greater MN activation in a variety of brain regions for musicians, with these differences more pronounced in the "Enjoyment" mode. Our findings suggest that activation of MNs is not only initiated by the imagined action of an observed movement, but such activation is modulated by the level of musical expertise and knowledge of associated motor movements that the observer brings to the viewing situation. Enhanced MN activation in musicians may stem from imagining themselves actually playing the observed piece. Copyright © 2017 Elsevier Inc. All rights reserved.

Dipolarization in the inner magnetosphere during a geomagnetic storm on 7 October 2015

NASA Astrophysics Data System (ADS)

Matsui, H.; Erickson, P. J.; Foster, J. C.; Torbert, R. B.; Argall, M. R.; Anderson, B. J.; Blake, J. B.; Cohen, I. J.; Ergun, R.; Farrugia, C. J.; Khotyaintsev, Y. V.; Korth, H.; Lindqvist, P. A.; Magnes, W.; Marklund, G. T.; Mauk, B.; Paulson, K. W.; Russell, C.; Strangeway, R. J.; Turner, D. L.

2016-12-01

A dipolarization event was observed by the Magnetospheric Multiscale (MMS) spacecraft at L=3.8 and 19.8 magnetic local time (MLT) starting at 23:42:36 UT on 7 October 2015. The magnetic and electric fields showed initially coherent variations between the spacecraft. The sunward convection turned tailward after the dipolarization. The observation is interpreted in terms of the pressure balance or the momentum equation. This was followed by a region traversed where the fields were irregular. The scale length was of the order of the ion gyroradius, suggesting the kinetic nature of the fluctuations. Combination of the multi-instrument, multi-spacecraft data reveals a more detailed picture of the dipolarization event in the inner magnetosphere. Conjunction ionosphere-plasmasphere observations from DMSP, two-dimensional GPS TEC, the Millstone Hill mid-latitude incoherent scatter radar, and AMPERE measurements imply that MMS observations are located on the poleward edge of the ionospheric trough where Region 2 field aligned currents flow.

Dipolarization in the inner magnetosphere during a geomagnetic storm on 7 October 2015

NASA Astrophysics Data System (ADS)

Matsui, H.; Erickson, P. J.; Foster, J. C.; Torbert, R. B.; Argall, M. R.; Anderson, B. J.; Blake, J. B.; Cohen, I. J.; Ergun, R. E.; Farrugia, C. J.; Khotyaintsev, Yu. V.; Korth, H.; Lindqvist, P.-A.; Magnes, W.; Marklund, G. T.; Mauk, B. H.; Paulson, K. W.; Russell, C. T.; Strangeway, R. J.; Turner, D. L.

2016-09-01

A dipolarization event was observed by the Magnetospheric Multiscale (MMS) spacecraft at L = 3.8 and 19.8 magnetic local time starting at ˜23:42:36 UT on 7 October 2015. The magnetic and electric fields showed initially coherent variations between the spacecraft. The sunward convection turned tailward after the dipolarization. The observation is interpreted in terms of the pressure balance or the momentum equation. This was followed by a region traversed where the fields were irregular. The scale length was of the order of the ion gyroradius, suggesting the kinetic nature of the fluctuations. Combination of the multi-instrument, multispacecraft data reveals a more detailed picture of the dipolarization event in the inner magnetosphere. Conjunction ionosphere-plasmasphere observations from DMSP, two-dimensional GPS total electron content, the Millstone Hill midlatitude incoherent scatter radar, and AMPERE measurements imply that MMS observations are located on the poleward edge of the ionospheric trough where Region 2 field-aligned currents flow.

(abstract) Short Time Period Variations in Jupiter's Synchrotron Radiation

NASA Technical Reports Server (NTRS)

Bolton, S. J.; Klein, M. J.; Gulkis, S.; Foster, R.; Heiles, C.; Pater, I. de

1994-01-01

The long term time variability of Jupiter's synchrotron radiation on yearly time scales has been established for some time. For many years, theorists have speculated about the effects variations in the solar wind, solar flux, Io, the Io torus, and Jupiter's magnetic field have on the ultra-relativistic electron population responsible for the emission. Early observational results suggested the additional possibility of a short term time variability, on timescales of days to weeks. In 1989 a program designed to investigate the existence of short term time variability using the 85 foot Hat Creek radio telescope operating at 1400 MHz was initiated. The availability of a dedicated telescope provided the opportunity, for the first time, to obtain numerous observations over the full Jupiter rotation period. These and future observations will enable two important studies, characterization and confirmation of possible short term variations, and the investigation of the stability of Jupiter's synchrotron emission beaming curve. Analysis of Hat Creek observations and early results from the Maryland Point Naval research Laboratory will be presented.

The interactions of normal and hyperactive children with their mothers in free play and structured tasks.

PubMed

Cunningham, C E; Barkley, R A

1979-03-01

Groups of 20 normal and 20 hyperactive boys ranging in age from 6 to 12 years were observed interacting with their mothers in 15-min free-play and 15-min structured-task situations. Using a 15-sec interval coding procedure, 1 observer recorded the mother's response to specific antecedent behaviors of the child while a second observer recorded the child's response to specific behaviors of the mother. Hyperactive boys proved more active, less compliant, and less likely to remain on task than nonhyperactive peers. Mothers of hyperactive boys were less likely to respond positively to the child's social interactions, solitary play activities, or compliant on-task behavior. In addition, mothers of hyperactive boys imposed more structure and control on the child's play, social interactions, and task-oriented activities. It is suggested that the controlling intrusive style observed among the mothers of hyperactive boys, while initially a response to the child's overactive, impulsive, inattentive style, may further contribute to the child's behavioral difficulties.

Upward electrical discharges observed above Tropical Depression Dorian

PubMed Central

Liu, Ningyu; Spiva, Nicholas; Dwyer, Joseph R.; Rassoul, Hamid K.; Free, Dwayne; Cummer, Steven A.

2015-01-01

Observation of upward electrical discharges from thunderstorms has been sporadically reported in the scientific literature. According to their terminal altitudes, they are classified as starters (20–30 km), jets (40–50 km) and gigantic jets (70–90 km). They not only have a significant impact on the occupied atmospheric volumes but also electrically couple different atmospheric regions. However, as they are rare and unpredictable, our knowledge of them has been built on observations that typically record only one type of such discharges. Here we report a close-distance observation of seven upward discharges including one starter, two jets and four gigantic jets above Tropical Depression Dorian. Our optical and electromagnetic data indicate that all events are of negative polarity, suggesting they are initiated in the same thundercloud charge region. The data also indicate that the lightning-like discharge channel can extend above thunderclouds by about 30 km, but the discharge does not emit low-frequency electromagnetic radiation as normal lightning. PMID:25607345

Red blood cell folate and plasma folate are not associated with risk of incident colorectal cancer in the Women's Health Initiative observational study.

PubMed

Neuhouser, Marian L; Cheng, Ting-Yuan David; Beresford, Shirley A A; Brown, Elissa; Song, Xiaoling; Miller, Joshua W; Zheng, Yingye; Thomson, Cynthia A; Shikany, James M; Vitolins, Mara Z; Rohan, Thomas; Green, Ralph; Ulrich, Cornelia M

2015-08-15

The relationship between folate and colorectal cancer (CRC) risk is unclear. We investigated the association of two biomarkers of folate status, plasma folate and red blood cell (RBC) folate, with CRC risk using a nested case-control design in the Women's Health Initiative Observational Study. Postmenopausal women (n = 93,676) aged 50-79 years were enrolled in the Women's Health Initiative Observational Study (1993-1998). A fasting blood draw and extensive health, dietary and lifestyle data were collected upon enrollment. Through 2008, 988 incident CRC cases were reported and confirmed with medical records adjudication. Cases and controls were matched on age (± 3 years), enrollment date (± 1 year), race/ethnicity, blood draw date (± 6 months) and hysterectomy status. Plasma and RBC folate were determined by radio assay. Folate biomarker values were divided into quartiles, and conditional logistic regression estimated odds ratios (ORs) and 95% confidence intervals (CI) for the associations of folate with total CRC, by tumor site and by stage at diagnosis. Additional analyses examined whether risks varied across time periods corresponding to the United States folic acid fortification policy: prefortification (1994-1995), perifortification (1996-1997) and postfortification (1998). ORs for overall CRC risk comparing Q4 vs. Q1 were 0.91 (95% CI 0.67-1.24) and 0.91 (95% CI 0.67-1.23) for RBC and plasma folate, respectively. There were no changes in risk attributable to food supply fortification. These results do not support an overall association of folate with CRC risk and suggest that folic acid fortification of the US food supply did not alter the associations in these postmenopausal women. © 2015 UICC.

Chronic hepatitis C virus patients with breakthroughs during interferon treatment can successfully be retreated with consensus interferon. The Consensus Interferon Study Group.

PubMed

Heathcote, E J; James, S; Mullen, K D; Hauser, S C; Rosenblate, H; Albert, D G

1999-08-01

Patients with chronic hepatitis C who have not had a sustained hepatitis C virus (HCV)-RNA response or serum alanine transaminase (ALT) response to a 6-month course of interferon (IFN) may respond to higher dose retreatment with consensus interferon (CIFN). Some nonresponders to initial IFN treatment have a transient response defined as undetectable HCV RNA or normalization of ALT during treatment, but subsequently have a "breakthrough" while still on treatment. The aim of this study was to determine if nonresponders who had breakthroughs responded differently to CIFN retreatment than nonresponders without breakthroughs using data from a large, multicenter trial. ALT and HCV RNA were monitored frequently during initial IFN therapy (either 9 mcg CIFN or 3 MU IFN-alpha2b 3 times per week). HCV-RNA breakthroughs were observed in 86 of 467 (18%) of all treated patients, and ALT breakthroughs were observed in 90 of 467 (19%) of all treated patients. There was no association between breakthroughs and the presence of either binding or neutralizing anti-IFN antibodies. When the patients who were nonresponders to initial IFN treatment were retreated with CIFN (15 mcg) for 12 months, 27% of those with viral breakthroughs had a sustained viral response compared with 8% in prior nonresponders without breakthroughs (P =.102). Sustained ALT responses were observed in 39% with breakthroughs compared with 10% in those without breakthroughs (P =.014). The data suggest that prior nonresponders with breakthroughs have a greater chance of responding to retreatment than do nonresponders without breakthroughs. However, most breakthrough patients would be missed unless repeated HCV-RNA testing were conducted during therapy.

Primary cutaneous marginal zone B-cell lymphoma: response to treatment and disease-free survival in a series of 137 patients.

PubMed

Servitje, Octavio; Muniesa, Cristina; Benavente, Yolanda; Monsálvez, Verónica; Garcia-Muret, M Pilar; Gallardo, Fernando; Domingo-Domenech, Eva; Lucas, Anna; Climent, Fina; Rodriguez-Peralto, Jose L; Ortiz-Romero, Pablo L; Sandoval, Juan; Pujol, Ramon M; Estrach, M Teresa

2013-09-01

Primary cutaneous marginal zone B-cell lymphomas are low-grade lymphomas running an indolent course. Skin relapses have been frequently reported but little information about disease-free survival (DFS) is available. We sought to evaluate relapse rate and DFS in patients with primary cutaneous marginal zone B-cell lymphomas. Clinical features, European Organization for Research and Treatment of Cancer/International Society for Cutaneous Lymphomas stage, light chain restriction, clonality, treatments, skin relapses, DFS, stage progression, extracutaneous disease, and outcome are analyzed in a series of 137 patients. Patients were classified as solitary lesion (T1) (n = 70; 51%), regional skin involvement (T2) (n = 40; 29%), and generalized skin lesions (T3) (n = 27; 20%). Surgical excision, local radiotherapy, or a combination were the initial treatment in 118 patients (86%). In 121 of 137 patients (88%) a complete remission was observed after initial treatment, including 99 of 106 patients (93%) with solitary or localized disease and 22 of 31 patients (71%) with multifocal lesions. Cutaneous relapses were observed in 53 patients (44%). Median DFS was 47 months. Patients with multifocal lesions or T3 disease showed higher relapse rate and shorter DFS. No significant differences were observed between surgery and radiotherapy, but surgery alone was associated with more recurrences at initial site. Overall survival at 5 and 10 years was 93%. Six patients (4%) developed extracutaneous disease during follow-up. This was a case series retrospective study. Our results support long-term follow-up in patients with primary cutaneous marginal zone B-cell lymphomas. Disseminated skin lesions have higher relapse rate and shorter DFS suggesting further investigation on systemic therapies in such a group of patients. Copyright © 2013 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.

EIT and SXT Observations of a Quiet Region Filament Ejection: First Eruption, Then Reconnection

NASA Technical Reports Server (NTRS)

Sterling, Alphonse C.; Moore, Ronald L.; Thompson, Barbara J.; Six, N. Frank (Technical Monitor)

2001-01-01

We observe a slow-onset quiet-region filament eruption with the EUV Imaging Telescope (EIT) on SOHO, and the Soft X-ray Telescope (SXT) on Yohkoh. This event occurred on 1999 April 18, and was likely the origin of a coronal mass ejection (CME) detected by SOHO at 08:30 UT on that day. In EIT, one-half of the filament shows two stages of evolution: Stage I is a slow, roughly constant upward movement at approx. 1 km per second lasting approximately 6.5 hours, and Stage 2 is a rapid upward eruption at approximately 16 kilometers per second occurring just before the filament disappears into interplanetary space. The other half of the filament shows little motion along the line-of-sight during the time of Stage 1, but erupts along with the rest of the filament during Stage 2. There is no obvious emission from the filament in SXT until Stage 2; at that time an arcade of EUV and soft X-ray loops forms first at the central location of the filament, and then expands outward along the length of the filament channel. A plot of EUV intensity versus time of the central portion of the filament (where the postflare loops initially form) shows a flat profile during Stage 1, and a rapid upturn after the start of Stage 2. This lightcurve is delayed from what would be expected if "tether-cutting" reconnection in the core of the erupting region were responsible for the initiation of the eruption. Rather, these observations suggest that a loss of stability of the magnetic field holding the filament initiates the eruption, with reconnection in the core region occurring only as a byproduct.

Divergent evolution of temozolomide resistance in glioblastoma stem cells is reflected in extracellular vesicles and coupled with radiosensitization.

PubMed

Garnier, Delphine; Meehan, Brian; Kislinger, Thomas; Daniel, Paul; Sinha, Ankit; Abdulkarim, Bassam; Nakano, Ichiro; Rak, Janusz

2018-01-22

Glioblastoma (GBM) is almost invariably fatal due to failure of standard therapy. The relapse of GBM following surgery, radiation, and systemic temozolomide (TMZ) is attributed to the ability of glioma stem cells (GSCs) to survive, evolve, and repopulate the tumor mass, events on which therapy exerts a poorly understood influence. Here we explore the molecular and cellular evolution of TMZ resistance as it emerges in vivo (xenograft models) in a series of human GSCs with either proneural (PN) or mesenchymal (MES) molecular characteristics. We observed that the initial response of GSC-initiated intracranial xenografts to TMZ is eventually replaced by refractory growth pattern. Individual tumors derived from the same isogenic GSC line expressed divergent and complex profiles of TMZ resistance markers, with a minor representation of O6-methylguanine DNA methyltransferase (MGMT) upregulation. In several independent TMZ-resistant tumors originating from MES GSCs we observed a consistent diminution of mesenchymal features, which persisted in cell culture and correlated with increased expression of Nestin, decline in transglutaminase 2 and sensitivity to radiation. The corresponding mRNA expression profiles reflective of TMZ resistance and stem cell phenotype were recapitulated in the transcriptome of exosome-like extracellular vesicles (EVs) released by GSCs into the culture medium. Intrinsic changes in the tumor-initiating cell compartment may include loss of subtype characteristics and reciprocal alterations in sensitivity to chemo- and radiation therapy. These observations suggest that exploiting therapy-induced changes in the GSC phenotype and alternating cycles of therapy may be explored to improve GBM outcomes. © The Author(s) 2017. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Exposure to the Neurotoxic Dinoflagellate, Alexandrium catenella, Induces Apoptosis of the Hemocytes of the Oyster, Crassostrea gigas

PubMed Central

Medhioub, Walid; Ramondenc, Simon; Vanhove, Audrey Sophie; Vergnes, Agnes; Masseret, Estelle; Savar, Veronique; Amzil, Zouher; Laabir, Mohamed; Rolland, Jean Luc

2013-01-01

This study assessed the apoptotic process occurring in the hemocytes of the Pacific oyster, Crassostrea gigas, exposed to Alexandrium catenella, a paralytic shellfish toxins (PSTs) producer. Oysters were experimentally exposed during 48 h to the toxic algae. PSTs accumulation, the expression of 12 key apoptotic-related genes, as well as the variation of the number of hemocytes in apoptosis was measured at time intervals during the experiment. Results show a significant increase of the number of hemocytes in apoptosis after 29 h of exposure. Two pro-apoptotic genes (Bax and Bax-like) implicated in the mitochondrial pathway were significantly upregulated at 21 h followed by the overexpression of two caspase executor genes (caspase-3 and caspase-7) at 29 h, suggesting that the intrinsic pathway was activated. No modulation of the expression of genes implicated in the cell signaling Fas-Associated protein with Death Domain (FADD) and initiation-phase (caspase-2) was observed, suggesting that only the extrinsic pathway was not activated. Moreover, the clear time-dependent upregulation of five (Bcl2, BI-1, IAP1, IAP7B and Hsp70) inhibitors of apoptosis-related genes associated with the return to the initial number of hemocytes in apoptosis at 48 h of exposure suggests the involvement of strong regulatory mechanisms of apoptosis occurring in the hemocytes of the Pacific oyster. PMID:24317471

Observation and numerical simulation of a convective initiation during COHMEX

NASA Technical Reports Server (NTRS)

Song, J. Aaron; Kaplan, Michael L.

1991-01-01

Under a synoptically undisturbed condition, a dual-peak convective lifecycle was observed with the COoperative Huntsville Meteorological EXperiment (COHMEX) observational network over a 24-hour period. The lifecycle included a multicell storm, which lasted about 6 hours, produced a peak rainrate exceeding 100 mm/hr, and initiated a downstream mesoscale convective system. The 24-hour accumulated rainfall of this event was the largest during the entire COHMEX. The downstream mesoscale convective system, unfortunately, was difficult to investigate quantitatively due to the lack of mesoscale observations. The dataset collected near the time of the multicell storm evolution, including its initiation, was one of the best datasets of COHMEX. In this study, the initiation of this multicell storm is chosen as the target of the numerical simulations.

Regulation of Mih1/Cdc25 by protein phosphatase 2A and casein kinase 1

PubMed Central

Pal, Gayatri; Paraz, Maria T.Z.; Kellogg, Douglas R.

2008-01-01

The Cdc25 phosphatase promotes entry into mitosis by removing cyclin-dependent kinase 1 (Cdk1) inhibitory phosphorylation. Previous work suggested that Cdc25 is activated by Cdk1 in a positive feedback loop promoting entry into mitosis; however, it has remained unclear how the feedback loop is initiated. To learn more about the mechanisms that regulate entry into mitosis, we have characterized the function and regulation of Mih1, the budding yeast homologue of Cdc25. We found that Mih1 is hyperphosphorylated early in the cell cycle and is dephosphorylated as cells enter mitosis. Casein kinase 1 is responsible for most of the hyperphosphorylation of Mih1, whereas protein phosphatase 2A associated with Cdc55 dephosphorylates Mih1. Cdk1 appears to directly phosphorylate Mih1 and is required for initiation of Mih1 dephosphorylation as cells enter mitosis. Collectively, these observations suggest that Mih1 regulation is achieved by a balance of opposing kinase and phosphatase activities. Because casein kinase 1 is associated with sites of polar growth, it may regulate Mih1 as part of a signaling mechanism that links successful completion of growth-related events to cell cycle progression. PMID:18316413

The Anatomy of Action Systems: Task Differentiation When Learning an EMG Controlled Game

PubMed Central

van Dijk, Ludger; Heerschop, Anniek; van der Sluis, Corry K.; Bongers, Raoul M.

2016-01-01

This study aims to determine to what extent the task for an action system in its initial development relies on functional and anatomical components. Fifty-two able-bodied participants were randomly assigned to one of three experimental groups or to a control group. As a pre- and post-test all groups performed a computer game with the same goal and using the same musculature. One experimental group also trained to perform this test, while the other two experimental groups learned to perform a game that differed either in its goal or in the musculature used. The observed change in accuracy indicated that retaining the goal of the task or the musculature used equally increased transfer performance relative to controls. Conversely, changing either the goal or the musculature equally decreased transfer relative to training the test. These results suggest that in the initial development of an action system, the task to which the system pertains is not specified solely by either the goal of the task or the anatomical structures involved. It is suggested that functional specificity and anatomical dependence might equally be outcomes of continuously differentiating activity. PMID:28018278