The natural history of untreated Chlamydia trachomatis infection in the interval between screening and returning for treatment.

PubMed

Geisler, William M; Wang, Chengbin; Morrison, Sandra G; Black, Carolyn M; Bandea, Claudiu I; Hook, Edward W

2008-02-01

Studies of the natural history of genital chlamydial infections in humans are sparse and have had study design limitations. An improved understanding of chlamydial natural history may influence recommendations for elements of control efforts such as chlamydia screening frequency or time parameters for partner notification. Addressing limitations of prior studies in part, we are prospectively studying chlamydial natural history in sexually transmitted diseases clinic patients in the interval between screening and returning for treatment of positive chlamydial tests. Results of repeat chlamydial testing and clinical outcomes and their associated predictors are being evaluated. In the initial 129 subjects, 89% were female, 88% were black, median age was 21 years, and the median interval between screening and treatment was 13 days. Based on nucleic acid amplification testing at treatment, spontaneous resolution of chlamydia occurred in 18%. Resolution was somewhat more common in subjects with longer intervals between screening and treatment. Persisting infections more often progressed to develop clinical signs at the time of treatment (e.g., urethritis or cervicitis). Two women and one man developed chlamydial complications between screening and treatment. Our findings demonstrate that although spontaneous resolution of chlamydia is common, many persons with persisting chlamydia progress to develop signs of infection and some develop complications.

ePRISM: A case study in multiple proxy and mixed temporal resolution integration

USGS Publications Warehouse

Robinson, Marci M.; Dowsett, Harry J.

2010-01-01

As part of the Pliocene Research, Interpretation and Synoptic Mapping (PRISM) Project, we present the ePRISM experiment designed I) to provide climate modelers with a reconstruction of an early Pliocene warm period that was warmer than the PRISM interval (similar to 3.3 to 3.0 Ma), yet still similar in many ways to modern conditions and 2) to provide an example of how best to integrate multiple-proxy sea surface temperature (SST) data from time series with varying degrees of temporal resolution and age control as we begin to build the next generation of PRISM, the PRISM4 reconstruction, spanning a constricted time interval. While it is possible to tie individual SST estimates to a single light (warm) oxygen isotope event, we find that the warm peak average of SST estimates over a narrowed time interval is preferential for paleoclimate reconstruction as it allows for the inclusion of more records of multiple paleotemperature proxies.

Computational Identification of Mechanistic Factors That Determine the Timing and Intensity of the Inflammatory Response

DTIC Science & Technology

2016-05-09

inflammation. Author Summary A recent approach to quantitatively characterize the timing and intensity of the inflamma- tory response relies on the use of...Fig 1). The quantitative properties of these trajecto- ries vary as a result of differences in inflammatory conditions and scenarios. Recently, four... quantitative indices [namely, peak height (Cmax), activation time (Tact), resolution interval (Ri), and resolution plateau (Rp)] (Fig 1) were introduced

Optical timing receiver for the NASA laser ranging system. Part 2: High precision time interval digitizer

NASA Technical Reports Server (NTRS)

Leskovar, B.; Turko, B.

1977-01-01

The development of a high precision time interval digitizer is described. The time digitizer is a 10 psec resolution stop watch covering a range of up to 340 msec. The measured time interval is determined as a separation between leading edges of a pair of pulses applied externally to the start input and the stop input of the digitizer. Employing an interpolation techniques and a 50 MHz high precision master oscillator, the equivalent of a 100 GHz clock frequency standard is achieved. Absolute accuracy and stability of the digitizer are determined by the external 50 MHz master oscillator, which serves as a standard time marker. The start and stop pulses are fast 1 nsec rise time signals, according to the Nuclear Instrument means of tunnel diode discriminators. Firing level of the discriminator define start and stop points between which the time interval is digitized.

Nonuniform sampling and non-Fourier signal processing methods in multidimensional NMR

PubMed Central

Mobli, Mehdi; Hoch, Jeffrey C.

2017-01-01

Beginning with the introduction of Fourier Transform NMR by Ernst and Anderson in 1966, time domain measurement of the impulse response (the free induction decay, FID) consisted of sampling the signal at a series of discrete intervals. For compatibility with the discrete Fourier transform (DFT), the intervals are kept uniform, and the Nyquist theorem dictates the largest value of the interval sufficient to avoid aliasing. With the proposal by Jeener of parametric sampling along an indirect time dimension, extension to multidimensional experiments employed the same sampling techniques used in one dimension, similarly subject to the Nyquist condition and suitable for processing via the discrete Fourier transform. The challenges of obtaining high-resolution spectral estimates from short data records using the DFT were already well understood, however. Despite techniques such as linear prediction extrapolation, the achievable resolution in the indirect dimensions is limited by practical constraints on measuring time. The advent of non-Fourier methods of spectrum analysis capable of processing nonuniformly sampled data has led to an explosion in the development of novel sampling strategies that avoid the limits on resolution and measurement time imposed by uniform sampling. The first part of this review discusses the many approaches to data sampling in multidimensional NMR, the second part highlights commonly used methods for signal processing of such data, and the review concludes with a discussion of other approaches to speeding up data acquisition in NMR. PMID:25456315

Quantitative investigation of resolution increase of free-flow electrophoresis via simple interval sample injection and separation.

PubMed

Shao, Jing; Fan, Liu-Yin; Cao, Cheng-Xi; Huang, Xian-Qing; Xu, Yu-Quan

2012-07-01

Interval free-flow zone electrophoresis (FFZE) has been used to suppress sample band broadening greatly hindering the development of free-flow electrophoresis (FFE). However, there has been still no quantitative study on the resolution increase of interval FFZE. Herein, we tried to make a comparison between bandwidths in interval FFZE and continuous one. A commercial dye with methyl green and crystal violet was well chosen to show the bandwidth. The comparative experiments were conducted under the same sample loading of the model dye (viz. 3.49, 1.75, 1.17, and 0.88 mg/h), the same running time (viz. 5, 10, 15, and 20 min), and the same flux ratio between sample and background buffer (= 10.64 × 10⁻³). Under the given conditions, the experiments demonstrated that (i) the band broadening was evidently caused by hydrodynamic factor in continuous mode, and (ii) the interval mode could clearly eliminate the hydrodynamic broadening existing in continuous mode, greatly increasing the resolution of dye separation. Finally, the interval FFZE was successfully used for the complete separation of two-model antibiotics (herein pyoluteorin and phenazine-1-carboxylic acid coexisting in fermentation broth of a new strain Pseudomonas aeruginosa M18), demonstrating the feasibility of interval FFZE mode for separation of biomolecules. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Analysis of a trial assessing the long-term effectiveness of salicylic acid plasters compared with scalpel debridement in facilitating corn resolution in patients with multiple corns.

PubMed

Stephenson, John; Farndon, Lisa; Concannon, Michael

2016-06-01

This study assesses the effect of salicylic acid plasters on the time to resolution of 324 corns experienced by 201 participants taking part in a randomized controlled trial. While the rate of corn resolution was substantively higher in the treatment group than in the control group, treatment was found to be not significantly related to time to corn recurrence when analyzed over the full 12-month follow-up period. Parametric survival analysis modeling of interval-censored data and incorporating patient-specific frailty terms was utilized, to model correlation of corns within patients (hazard ratio [HR], 1.189; 95% confidence interval [CI], 0.780-1.813; P = 0.422). Median resolution times were 10.0 months for corns in the treatment group and 13.4 months for corns in the control group. Controlling for treatment, corn type was found to be related to resolution time, with dorsal/interdigital (ID) corns showing better resolution than plantar corns (HR, 1.670; 95% CI, 1.061-2.630; P = 0.027). Median resolution times were 5.9 months for dorsal/ID corns and 14.9 months for plantar corns. Secondary measures relating to quality of life (QoL) and foot-related disability, using the EQ-5D questionnaire and the Manchester Foot Pain and Disability Index (MFPDI), were also assessed at the patient level in multivariate models. Treatment was not significantly related to any of these measures over the whole period of analysis. However, a trend analysis revealed a quadratic trend in QoL and MFPDI scores, arising from a substantive initial improvement between baseline and 3 months, followed by a gradual decrease between 3 and 12 months. © 2015 Japanese Dermatological Association.

Spectral and temporal resolutions of information-bearing acoustic changes for understanding vocoded sentencesa)

PubMed Central

Stilp, Christian E.; Goupell, Matthew J.

2015-01-01

Short-time spectral changes in the speech signal are important for understanding noise-vocoded sentences. These information-bearing acoustic changes, measured using cochlea-scaled entropy in cochlear implant simulations [CSECI; Stilp et al. (2013). J. Acoust. Soc. Am. 133(2), EL136–EL141; Stilp (2014). J. Acoust. Soc. Am. 135(3), 1518–1529], may offer better understanding of speech perception by cochlear implant (CI) users. However, perceptual importance of CSECI for normal-hearing listeners was tested at only one spectral resolution and one temporal resolution, limiting generalizability of results to CI users. Here, experiments investigated the importance of these informational changes for understanding noise-vocoded sentences at different spectral resolutions (4–24 spectral channels; Experiment 1), temporal resolutions (4–64 Hz cutoff for low-pass filters that extracted amplitude envelopes; Experiment 2), or when both parameters varied (6–12 channels, 8–32 Hz; Experiment 3). Sentence intelligibility was reduced more by replacing high-CSECI intervals with noise than replacing low-CSECI intervals, but only when sentences had sufficient spectral and/or temporal resolution. High-CSECI intervals were more important for speech understanding as spectral resolution worsened and temporal resolution improved. Trade-offs between CSECI and intermediate spectral and temporal resolutions were minimal. These results suggest that signal processing strategies that emphasize information-bearing acoustic changes in speech may improve speech perception for CI users. PMID:25698018

A high-resolution time-to-digital converter using a three-level resolution

NASA Astrophysics Data System (ADS)

Dehghani, Asma; Saneei, Mohsen; Mahani, Ali

2016-08-01

In this article, a three-level resolution Vernier delay line time-to-digital converter (TDC) was proposed. The proposed TDC core was based on the pseudo-differential digital architecture that made it insensitive to nMOS and pMOS transistor mismatches. It also employed a Vernier delay line (VDL) in conjunction with an asynchronous read-out circuitry. The time interval resolution was equal to the difference of delay between buffers of upper and lower chains. Then, via the extra chain included in the lower delay line, resolution was controlled and power consumption was reduced. This method led to high resolution and low power consumption. The measurement results of TDC showed a resolution of 4.5 ps, 12-bit output dynamic range, and integral nonlinearity of 1.5 least significant bits. This TDC achieved the consumption of 68.43 µW from 1.1-V supply.

Central tendency effects in time interval reproduction in autism

PubMed Central

Karaminis, Themelis; Cicchini, Guido Marco; Neil, Louise; Cappagli, Giulia; Aagten-Murphy, David; Burr, David; Pellicano, Elizabeth

2016-01-01

Central tendency, the tendency of judgements of quantities (lengths, durations etc.) to gravitate towards their mean, is one of the most robust perceptual effects. A Bayesian account has recently suggested that central tendency reflects the integration of noisy sensory estimates with prior knowledge representations of a mean stimulus, serving to improve performance. The process is flexible, so prior knowledge is weighted more heavily when sensory estimates are imprecise, requiring more integration to reduce noise. In this study we measure central tendency in autism to evaluate a recent theoretical hypothesis suggesting that autistic perception relies less on prior knowledge representations than typical perception. If true, autistic children should show reduced central tendency than theoretically predicted from their temporal resolution. We tested autistic and age- and ability-matched typical children in two child-friendly tasks: (1) a time interval reproduction task, measuring central tendency in the temporal domain; and (2) a time discrimination task, assessing temporal resolution. Central tendency reduced with age in typical development, while temporal resolution improved. Autistic children performed far worse in temporal discrimination than the matched controls. Computational simulations suggested that central tendency was much less in autistic children than predicted by theoretical modelling, given their poor temporal resolution. PMID:27349722

Resolution of hypertension and proteinuria after preeclampsia.

PubMed

Berks, Durk; Steegers, Eric A P; Molas, Marek; Visser, Willy

2009-12-01

To estimate the time required for hypertension and proteinuria to resolve after preeclampsia, and to estimate how this time to resolution correlates with the levels of blood pressure and proteinuria during preeclampsia and prolonging pregnancy after the development of preeclampsia. This is a historic prospective cohort study of 205 preeclamptic women who were admitted between 1990 and 1992 at the Erasmus MC Medical Centre, Rotterdam, The Netherlands. Data were collected at 1.5, 3, 6, 12, 18, and 24 months after delivery. Hypertension was defined as a blood pressure 140/90 mm Hg or higher or use of antihypertensive drugs. Proteinuria was defined as 0.3 g/d or more. Resolution of hypertension and proteinuria were analyzed with the Turnbull extension to the Kaplan-Meier procedure. Correlations were calculated with an accelerated failure time model. At 3 months postpartum, 39% of women still had hypertension, which decreased to 18% at 2 years postpartum. Resolution time increased by 60% (P<.001) for every 10-mm Hg increase in maximal systolic blood pressure, 40% (P=.044) for every 10-mm Hg increase in maximal diastolic blood pressure, and 3.6% (P=.001) for every 1-day increase in the diagnosis-to-delivery interval. At 3 months postpartum, 14% still had proteinuria, which decreased to 2% at 2 years postpartum. Resolution time increased by 16% (P=.001) for every 1-g/d increase in maximal proteinuria. Gestational age at onset of preeclampsia was not correlated with resolution time of hypertension and proteinuria. The severity of preeclampsia and the time interval between diagnosis and delivery are associated with postpartum time to resolution of hypertension and proteinuria. After preeclampsia, it can take up to 2 years for hypertension and proteinuria to resolve. Therefore, the authors suggest that further invasive diagnostic tests for underlying renal disease may be postponed until 2 years postpartum. III.

Optimal Exploitation of the Temporal and Spatial Resolution of SEVIRI for the Nowcasting of Clouds

NASA Astrophysics Data System (ADS)

Sirch, Tobias; Bugliaro, Luca

2015-04-01

Optimal Exploitation of the Temporal and Spatial Resolution of SEVIRI for the Nowcasting of Clouds An algorithm was developed to forecast the development of water and ice clouds for the successive 5-120 minutes separately using satellite data from SEVIRI (Spinning Enhanced Visible and Infrared Imager) aboard Meteosat Second Generation (MSG). In order to derive cloud cover, optical thickness and cloud top height of high ice clouds "The Cirrus Optical properties derived from CALIOP and SEVIRI during day and night" (COCS, Kox et al. [2014]) algorithm is applied. For the determination of the liquid water clouds the APICS ("Algorithm for the Physical Investigation of Clouds with SEVIRI", Bugliaro e al. [2011]) cloud algorithm is used, which provides cloud cover, optical thickness and effective radius. The forecast rests upon an optical flow method determining a motion vector field from two satellite images [Zinner et al., 2008.] With the aim of determining the ideal time separation of the satellite images that are used for the determination of the cloud motion vector field for every forecast horizon time the potential of the better temporal resolution of the Meteosat Rapid Scan Service (5 instead of 15 minutes repetition rate) has been investigated. Therefore for the period from March to June 2013 forecasts up to 4 hours in time steps of 5 min based on images separated by a time interval of 5 min, 10 min, 15 min, 30 min have been created. The results show that Rapid Scan data produces a small reduction of errors for a forecast horizon up to 30 minutes. For the following time steps forecasts generated with a time interval of 15 min should be used and for forecasts up to several hours computations with a time interval of 30 min provide the best results. For a better spatial resolution the HRV channel (High Resolution Visible, 1km instead of 3km maximum spatial resolution at the subsatellite point) has been integrated into the forecast. To detect clouds the difference of the measured albedo from SEVIRI and the clear-sky albedo provided by MODIS has been used and additionally the temporal development of this quantity. A pre-requisite for this work was an adjustment of the geolocation accuracy for MSG and MODIS by shifting the MODIS data and quantifying the correlation between both data sets.

Nonuniform sampling and non-Fourier signal processing methods in multidimensional NMR.

PubMed

Mobli, Mehdi; Hoch, Jeffrey C

2014-11-01

Beginning with the introduction of Fourier Transform NMR by Ernst and Anderson in 1966, time domain measurement of the impulse response (the free induction decay, FID) consisted of sampling the signal at a series of discrete intervals. For compatibility with the discrete Fourier transform (DFT), the intervals are kept uniform, and the Nyquist theorem dictates the largest value of the interval sufficient to avoid aliasing. With the proposal by Jeener of parametric sampling along an indirect time dimension, extension to multidimensional experiments employed the same sampling techniques used in one dimension, similarly subject to the Nyquist condition and suitable for processing via the discrete Fourier transform. The challenges of obtaining high-resolution spectral estimates from short data records using the DFT were already well understood, however. Despite techniques such as linear prediction extrapolation, the achievable resolution in the indirect dimensions is limited by practical constraints on measuring time. The advent of non-Fourier methods of spectrum analysis capable of processing nonuniformly sampled data has led to an explosion in the development of novel sampling strategies that avoid the limits on resolution and measurement time imposed by uniform sampling. The first part of this review discusses the many approaches to data sampling in multidimensional NMR, the second part highlights commonly used methods for signal processing of such data, and the review concludes with a discussion of other approaches to speeding up data acquisition in NMR. Copyright © 2014 Elsevier B.V. All rights reserved.

Testing the limits of Paleozoic chronostratigraphic correlation via high-resolution (13Ccarb) biochemostratigraphy across the Llandovery–Wenlock (Silurian) boundary: Is a unified Phanerozoic time scale achievable?

USGS Publications Warehouse

Cramer, Bradley D.; Loydell, David K.; Samtleben, Christian; Munnecke, Axel; Kaljo, Dimitri; Mannik, Peep; Martma, Tonu; Jeppsson, Lennart; Kleffner, Mark A.; Barrick, James E.; Johnson, Craig A.; Emsbo, Poul; Joachimski, Michael M.; Bickert, Torsten; Saltzman, Matthew R.

2010-01-01

The resolution and fidelity of global chronostratigraphic correlation are direct functions of the time period under consideration. By virtue of deep-ocean cores and astrochronology, the Cenozoic and Mesozoic time scales carry error bars of a few thousand years (k.y.) to a few hundred k.y. In contrast, most of the Paleozoic time scale carries error bars of plus or minus a few million years (m.y.), and chronostratigraphic control better than ??1 m.y. is considered "high resolution." The general lack of Paleozoic abyssal sediments and paucity of orbitally tuned Paleozoic data series combined with the relative incompleteness of the Paleozoic stratigraphic record have proven historically to be such an obstacle to intercontinental chronostratigraphic correlation that resolving the Paleozoic time scale to the level achieved during the Mesozoic and Cenozoic was viewed as impractical, impossible, or both. Here, we utilize integrated graptolite, conodont, and carbonate carbon isotope (??13Ccarb) data from three paleocontinents (Baltica, Avalonia, and Laurentia) to demonstrate chronostratigraphic control for upper Llando very through middle Wenlock (Telychian-Sheinwoodian, ~436-426 Ma) strata with a resolution of a few hundred k.y. The interval surrounding the base of the Wenlock Series can now be correlated globally with precision approaching 100 k.y., but some intervals (e.g., uppermost Telychian and upper Shein-woodian) are either yet to be studied in sufficient detail or do not show sufficient biologic speciation and/or extinction or carbon isotopic features to delineate such small time slices. Although producing such resolution during the Paleozoic presents an array of challenges unique to the era, we have begun to demonstrate that erecting a Paleozoic time scale comparable to that of younger eras is achievable. ?? 2010 Geological Society of America.

Early to middle Miocene climate evolution: benthic oxygen and carbon isotope records from Walvis Ridge Site 1264.

NASA Astrophysics Data System (ADS)

Lourens, L. J.; Beddow, H.; Liebrand, D.; Schrader, C.; Hilgen, F. J.

2016-12-01

Across the early to middle Miocene, high-resolution records from the Pacific Ocean indicate a dynamic climate system, encompassing a 2 Myr global warming event from 17 Ma to 14.7 Ma, followed by a major Cenozoic cooling step at 14.2 Ma -13.8 Ma. Currently, no high-resolution benthic record from the Atlantic Ocean exists covering both events, limiting global coverage of this intriguing period in Cenozoic climate evolution. Here, we present the first early to middle Miocene high-resolution from the Atlantic basin. These records, from Site 1264 on the Walvis Ridge, span a 5.5 Myr long interval (13.24-18.90 ma) in high temporal resolution ( 4 kyr) and are tuned to eccentricity. The d18O record shows a sudden (high-latitude) warming/deglaciation on Antarctica at 17.1 Ma, a rapid cooling/glaciation of Antarctica at 13.8 Ma, and high-amplitude ( 1‰) variability on astronomical time-scales throughout this interval. Together with other records from this time interval located in the Pacific, which show similar features, the data strongly suggests a highly dynamic global climate system. We find cooling steps in d18O at 14.7, 14.2 and 13.8 Ma, suggesting concurrent cooling in the Pacific and Atlantic deep waters during the MMCT. The benthic foraminiferal stable isotope records reveal that the dominant astronomical frequencies present at ODP Site 1264 during the early to middle Miocene interval are the 405 kyr and 110 kyr eccentricity periodicities. This is a contrast to other early to middle Miocene records from drill-sites in the Pacific and South China Sea, which show a strong expression of obliquity in particular between 14.2 and 14.7 Ma.

The Lambert-Beer law in time domain form and its application.

PubMed

Mosorov, Volodymyr

2017-10-01

The majority of current radioisotope gauges utilize measurements of intensity for a chosen sampling time interval using a detector. Such an approach has several disadvantages: temporal resolution of the gauge is fixed and the accuracy of the measurements is not the same for different count rate. The solution can be the use of a stronger radioactive source, but it will be conflicted with ALARA (As Low As Reasonably Achievable) principle. Therefore, the article presents an alternative approach which is based on modified Lambert-Beer law. The basis of the approach is the registration of time intervals instead of the registration of counts. It allows to increase the temporal resolution of a gauge without the necessity of using a stronger radioactive source and the accuracy of the measurements will not depend on count rate. Copyright © 2017 Elsevier Ltd. All rights reserved.

Retention of Esperanto Is Affected by Delay-Interval Task and Item Closure: A Partial Resolution of the Delay-Retention Effect

ERIC Educational Resources Information Center

Brosvic, Gary M.; Epstein, Michael L.; Dihoff, Roberta E.; Cook, Michael L.

2006-01-01

The present studies were undertaken to examine the effects of manipulating delay-interval task (Study 1) and timing of feedback (Study 2) on acquisition and retention. Participants completed a 100-item cumulative final examination, which included 50 items from each laboratory examination, plus 50 entirely new items. Acquisition and retention were…

Comparison of High-Resolution MR Imaging and Digital Subtraction Angiography for the Characterization and Diagnosis of Intracranial Artery Disease.

PubMed

Lee, N J; Chung, M S; Jung, S C; Kim, H S; Choi, C-G; Kim, S J; Lee, D H; Suh, D C; Kwon, S U; Kang, D-W; Kim, J S

2016-12-01

High-resolution MR imaging has recently been introduced as a promising diagnostic modality in intracranial artery disease. Our aim was to compare high-resolution MR imaging with digital subtraction angiography for the characterization and diagnosis of various intracranial artery diseases. Thirty-seven patients who had undergone both high-resolution MR imaging and DSA for intracranial artery disease were enrolled in our study (August 2011 to April 2014). The time interval between the high-resolution MR imaging and DSA was within 1 month. The degree of stenosis and the minimal luminal diameter were independently measured by 2 observers in both DSA and high-resolution MR imaging, and the results were compared. Two observers independently diagnosed intracranial artery diseases on DSA and high-resolution MR imaging. The time interval between the diagnoses on DSA and high-resolution MR imaging was 2 weeks. Interobserver diagnostic agreement for each technique and intermodality diagnostic agreement for each observer were acquired. High-resolution MR imaging showed moderate-to-excellent agreement (interclass correlation coefficient = 0.892-0.949; κ = 0.548-0.614) and significant correlations (R = 0.766-892) with DSA on the degree of stenosis and minimal luminal diameter. The interobserver diagnostic agreement was good for DSA (κ = 0.643) and excellent for high-resolution MR imaging (κ = 0.818). The intermodality diagnostic agreement was good (κ = 0.704) for observer 1 and moderate (κ = 0.579) for observer 2, respectively. High-resolution MR imaging may be an imaging method comparable with DSA for the characterization and diagnosis of various intracranial artery diseases. © 2016 by American Journal of Neuroradiology.

Generation of the global cloud free data set of MODIS

NASA Astrophysics Data System (ADS)

Oguro, Y.; Tsuchiya, K.

To extract temporal change of the land cover from remotely sensed data from space the generation of the reliable cloud free data set is the first priority item With the objectives of generating accurate global basic data and to find the effects of spectral and spatial resolution differences and observation time an attempt is made to generate reliable global cloud free data set of Terra and Aqua MODIS utilizing personal computers Out of 36 bands seven bands with similar spectral features to those of Landsat TM i e Band 1 through 7 are selected These bands cover the most important spectra to derive landcover features The procedure of the data set generation is as follows 1 Download the global Terra and Aqua MODIS day time data MOD02 Level-1B Calibrated Geolocation Data Set of 250 meter Band 1 and 2 and 500 meter Band 3 through 7 resolution from NASA web site 2 Separate the data into several BSQ Band SeQuential image and several text geolocation information of pixels files 3 The geolocation information is given to the pixels of several kms interval Based on the information resampling of the data are made at 1 2 and 1 4 degrees intervals of latitude and longitude thus the resampled pixels are distributed in the latitude and longitudinal axis plane at 1 4 degrees high resolution and 1 2 degrees low resolution intervals 4 A global data for one day is composed 5 Compute NDVI for each pixel 6 Compare the value of NDVI of successive days and keep the larger NDVI At the same time keep the values of each band of the day of the larger

Racial and ethnic differences in patient navigation: Results from the Patient Navigation Research Program.

PubMed

Ko, Naomi Y; Snyder, Frederick R; Raich, Peter C; Paskett, Electra D; Dudley, Donald J; Lee, Ji-Hyun; Levine, Paul H; Freund, Karen M

2016-09-01

Patient navigation was developed to address barriers to timely care and reduce cancer disparities. The current study explored navigation and racial and ethnic differences in time to the diagnostic resolution of a cancer screening abnormality. The authors conducted an analysis of the multisite Patient Navigation Research Program. Participants with an abnormal cancer screening test were allocated to either navigation or control. The unadjusted median time to resolution was calculated for each racial and ethnic group by navigation and control. Multivariable Cox proportional hazards models were fit, adjusting for sex, age, cancer abnormality type, and health insurance and stratifying by center of care. Among a sample of 7514 participants, 29% were non-Hispanic white, 43% were Hispanic, and 28% were black. In the control group, black individuals were found to have a longer median time to diagnostic resolution (108 days) compared with non-Hispanic white individuals (65 days) or Hispanic individuals (68 days) (P<.0001). In the navigated groups, black individuals had a reduction in the median time to diagnostic resolution (97 days) (P<.0001). In the multivariable models, among controls, black race was found to be associated with an increased delay to diagnostic resolution (hazard ratio, 0.77; 95% confidence interval, 0.69-0.84) compared with non-Hispanic white individuals, which was reduced in the navigated arm (hazard ratio, 0.85; 95% confidence interval, 0.77-0.94). Patient navigation appears to have the greatest impact among black patients, who had the greatest delays in care. Cancer 2016. © 2016 American Cancer Society. Cancer 2016;122:2715-2722. © 2016 American Cancer Society. © 2016 American Cancer Society.

Conservative management of extradural hematoma: A report of sixty-two cases.

PubMed

Zwayed, A Rahim H; Lucke-Wold, Brandon

2018-06-01

Extradural hematomas (EDH) are considered life threatening in that the risk for brain herniation is significant. The current accepted understanding within the literature is to treat EDH via surgical evacuation of the hematoma. In this case-series we report 62 cases of EDH managed conservatively without surgical intervention. Inclusion criteria were: Glasgow comma scale score 13-15, extradural hematoma confirmed by CT being less than 40 mm, less than 6 mm of midline shift, and no other surgical lesions present. Patients were initially observed in a surgical intensive care unit prior to discharge and had closely scheduled follow-up. Of the 62 cases none required emergent intervention and the majority had interval resolution of the epidural hematoma over time. Resolution was apparent by 21 days and definitive by 3 to 6 months. Patients with EDH who have a high Glasgow comma scale score 13-15, volume <40 mm, and less than 6 mm of midline shift should be considered for conservative management. Our study indicates that these patients will have interval resolution of hematoma over time without worsening of symptoms.

Design of time interval generator based on hybrid counting method

NASA Astrophysics Data System (ADS)

Yao, Yuan; Wang, Zhaoqi; Lu, Houbing; Chen, Lian; Jin, Ge

2016-10-01

Time Interval Generators (TIGs) are frequently used for the characterizations or timing operations of instruments in particle physics experiments. Though some "off-the-shelf" TIGs can be employed, the necessity of a custom test system or control system makes the TIGs, being implemented in a programmable device desirable. Nowadays, the feasibility of using Field Programmable Gate Arrays (FPGAs) to implement particle physics instrumentation has been validated in the design of Time-to-Digital Converters (TDCs) for precise time measurement. The FPGA-TDC technique is based on the architectures of Tapped Delay Line (TDL), whose delay cells are down to few tens of picosecond. In this case, FPGA-based TIGs with high delay step are preferable allowing the implementation of customized particle physics instrumentations and other utilities on the same FPGA device. A hybrid counting method for designing TIGs with both high resolution and wide range is presented in this paper. The combination of two different counting methods realizing an integratable TIG is described in detail. A specially designed multiplexer for tap selection is emphatically introduced. The special structure of the multiplexer is devised for minimizing the different additional delays caused by the unpredictable routings from different taps to the output. A Kintex-7 FPGA is used for the hybrid counting-based implementation of a TIG, providing a resolution up to 11 ps and an interval range up to 8 s.

Real-time flight conflict detection and release based on Multi-Agent system

NASA Astrophysics Data System (ADS)

Zhang, Yifan; Zhang, Ming; Yu, Jue

2018-01-01

This paper defines two-aircrafts, multi-aircrafts and fleet conflict mode, sets up space-time conflict reservation on the basis of safety interval and conflict warning time in three-dimension. Detect real-time flight conflicts combined with predicted flight trajectory of other aircrafts in the same airspace, and put forward rescue resolutions for the three modes respectively. When accorded with the flight conflict conditions, determine the conflict situation, and enter the corresponding conflict resolution procedures, so as to avoid the conflict independently, as well as ensure the flight safety of aimed aircraft. Lastly, the correctness of model is verified with numerical simulation comparison.

TOT measurement implemented in FPGA TDC

NASA Astrophysics Data System (ADS)

Fan, Huan-Huan; Cao, Ping; Liu, Shu-Bin; An, Qi

2015-11-01

Time measurement plays a crucial role for the purpose of particle identification in high energy physics experiments. With increasingly demanding physics goals and the development of electronics, modern time measurement systems need to meet the requirement of excellent resolution specification as well as high integrity. Based on Field Programmable Gate Arrays (FPGAs), FPGA time-to-digital converters (TDCs) have become one of the most mature and prominent time measurement methods in recent years. For correcting the time-walk effect caused by leading timing, a time-over-threshold (TOT) measurement should be added to the FPGA TDC. TOT can be obtained by measuring the interval between the signal leading and trailing edges. Unfortunately, a traditional TDC can recognize only one kind of signal edge, the leading or the trailing. Generally, to measure the interval, two TDC channels need to be used at the same time, one for leading, the other for trailing. However, this method unavoidably increases the amount of FPGA resources used and reduces the TDC's integrity. This paper presents one method of TOT measurement implemented in a Xilinx Virtex-5 FPGA. In this method, TOT measurement can be achieved using only one TDC input channel. The consumed resources and time resolution can both be guaranteed. Testing shows that this TDC can achieve resolution better than 15ps for leading edge measurement and 37 ps for TOT measurement. Furthermore, the TDC measurement dead time is about two clock cycles, which makes it good for applications with higher physics event rates. Supported by National Natural Science Foundation of China (11079003, 10979003)

Multicenter trial evaluating the use of covered self-expanding metal stents in benign biliary strictures: time to revisit our therapeutic options?

PubMed

Kahaleh, Michel; Brijbassie, Alan; Sethi, Amrita; Degaetani, Marisa; Poneros, John M; Loren, David E; Kowalski, Thomas E; Sejpal, Divyesh V; Patel, Sandeep; Rosenkranz, Laura; McNamara, Kevin N; Raijman, Isaac; Talreja, Jayant P; Gaidhane, Monica; Sauer, Bryan G; Stevens, Peter D

2013-09-01

Covered self-expanding metal stents are being used more frequently in benign biliary strictures (BBS). We report the results of a multicenter study with fully covered self-expanding metal stent (FCSEMS) placement for the management of BBS. : To prospectively evaluate the efficacy and safety of FCSEMS in the management of BBS. Patients with BBS from 6 tertiary care centers who received FCSEMS with flared ends between April 2009 and October 2010 were included in this retrospective study.Efficacy was measured after removal of FCSEMS by evaluating stricture resolution on the basis of symptom resolution, imaging, laboratory studies, and/or choledochoscopy at removal. Safety profile was evaluated by assessing postprocedural complications. A total of 133 patients (78, 58.6% males) with a mean age of 59.2±14.8 years with BBS received stents. Of the 133 stents placed, 97 (72.9%) were removed after a mean stent duration of 95.5±48.7 days. Stricture resolution after FCSEMS removal was as follows: postsurgical, 11/12 (91.6%); gallstone-related disease, 16/19 (84.2%); chronic pancreatitis, 26/31 (80.7%); other etiology, 4/5 (80.0%); and anastomotic strictures, 19/31(61.2%). Ninety-four patients were included in the logistic regression analyses. Patients who had indwelling stents for >90 days were 4.3 times more likely to have resolved strictures [odds ratio, 4.3 (95% confidence interval, 1.24-15.09)] and patients with nonmigrated stents were 5.4 times more likely to have resolved strictures [odds ratio, 5.4 (95% confidence interval, 1.001-29.29)]. FCSEMS for BBS had an acceptable rate of stricture resolution for postsurgical strictures, gallstone-related strictures, and those due to chronic pancreatitis. Predictors for stricture resolution include longer indwell time and absence of migration. Further study is warranted to assess long-term efficacy in a prospective manner with longer than 3-month time of stent indwelling time.

A Millennial-Scale Sea Surface Temperature Record From the North Atlantic Based on Diatoms

NASA Astrophysics Data System (ADS)

Miettinen, A.; Koc, N.

2008-12-01

Sea surfaces temperatures (SSTs) are generated from a 1000-year-long sediment core from the eastern flank of Reykjanes Ridge in the subpolar North Atlantic with a time resolution of 2-10 years. 54.3 cm long box core (Rapid 21-12B) and 370 cm long gravity core (RAPID 21-3K) were recovered from deep-sea sediments (2630 m water depth) during the RRS Charles Darwin cruise 159 in 2004. The box core is dated using the 210Pb method and it is continuously subsampled and investigated at 0.5 cm intervals for the last 230 years with a two years average time resolution. The gravity core is dated 14C AMS method and it is investigated continuously at 1.0 cm intervals with a ten years average resolution for the interval representing 230-1000 cal. years BP. August SSTs are reconstructed using marine planktonic diatom species with the Weighted Averages - Partial Least Squares (WA-PLS) method. Results achieved from the box core indicate August SST warming of c. 1 °C from 1773 AD to the present. The interval 1773-1830 represents the cold period at the investigated site. It is followed by warm period between 1830 and 1885. After this the temperature frequency is more stable with short cool events around 1890 and 1930. The last 60 years represent the warm period with a slow warming trend, especially during the past 25 years. However, results do not indicate distinct SST warming since 1870s. The most high-frequency SST variability with amplitude of c. 1 °C appears after 1970 indicating several very warm years, but also coldest years since 1820s.

High frequency, high time resolution time-to-digital converter employing passive resonating circuits.

PubMed

Ripamonti, Giancarlo; Abba, Andrea; Geraci, Angelo

2010-05-01

A method for measuring time intervals accurate to the picosecond range is based on phase measurements of oscillating waveforms synchronous with their beginning and/or end. The oscillation is generated by triggering an LC resonant circuit, whose capacitance is precharged. By using high Q resonators and a final active quenching of the oscillation, it is possible to conjugate high time resolution and a small measurement time, which allows a high measurement rate. Methods for fast analysis of the data are considered and discussed with reference to computing resource requirements, speed, and accuracy. Experimental tests show the feasibility of the method and a time accuracy better than 4 ps rms. Methods aimed at further reducing hardware resources are finally discussed.

Picosecond timing resolution detection of ggr-photons utilizing microchannel-plate detectors: experimental tests of quantum nonlocality and photon localization

NASA Astrophysics Data System (ADS)

Irby, Victor D.

2004-09-01

The concept and subsequent experimental verification of the proportionality between pulse amplitude and detector transit time for microchannel-plate detectors is presented. This discovery has led to considerable improvement in the overall timing resolution for detection of high-energy ggr-photons. Utilizing a 22Na positron source, a full width half maximum (FWHM) timing resolution of 138 ps has been achieved. This FWHM includes detector transit-time spread for both chevron-stack-type detectors, timing spread due to uncertainties in annihilation location, all electronic uncertainty and any remaining quantum mechanical uncertainty. The first measurement of the minimum quantum uncertainty in the time interval between detection of the two annihilation photons is reported. The experimental results give strong evidence against instantaneous spatial localization of ggr-photons due to measurement-induced nonlocal quantum wavefunction collapse. The experimental results are also the first that imply momentum is conserved only after the quantum uncertainty in time has elapsed (Yukawa H 1935 Proc. Phys. Math. Soc. Japan 17 48).

cyclostratigraphy, sequence stratigraphy and organic matter accumulation mechanism

NASA Astrophysics Data System (ADS)

Cong, F.; Li, J.

2016-12-01

The first member of Maokou Formation of Sichuan basin is composed of well preserved carbonate ramp couplets of limestone and marlstone/shale. It acts as one of the potential shale gas source rock, and is suitable for time-series analysis. We conducted time-series analysis to identify high-frequency sequences, reconstruct high-resolution sedimentation rate, estimate detailed primary productivity for the first time in the study intervals and discuss organic matter accumulation mechanism of source rock under sequence stratigraphic framework.Using the theory of cyclostratigraphy and sequence stratigraphy, the high-frequency sequences of one outcrop profile and one drilling well are identified. Two third-order sequences and eight fourth-order sequences are distinguished on outcrop profile based on the cycle stacking patterns. For drilling well, sequence boundary and four system tracts is distinguished by "integrated prediction error filter analysis" (INPEFA) of Gamma-ray logging data, and eight fourth-order sequences is identified by 405ka long eccentricity curve in depth domain which is quantified and filtered by integrated analysis of MTM spectral analysis, evolutive harmonic analysis (EHA), evolutive average spectral misfit (eASM) and band-pass filtering. It suggests that high-frequency sequences correlate well with Milankovitch orbital signals recorded in sediments, and it is applicable to use cyclostratigraphy theory in dividing high-frequency(4-6 orders) sequence stratigraphy.High-resolution sedimentation rate is reconstructed through the study interval by tracking the highly statistically significant short eccentricity component (123ka) revealed by EHA. Based on sedimentation rate, measured TOC and density data, the burial flux, delivery flux and primary productivity of organic carbon was estimated. By integrating redox proxies, we can discuss the controls on organic matter accumulation by primary production and preservation under the high-resolution sequence stratigraphic framework. Results show that high average organic carbon contents in the study interval are mainly attributed to high primary production. The results also show a good correlation between high organic carbon accumulation and intervals of transgression.

Initial Validation of NDVI time seriesfrom AVHRR, VEGETATION, and MODIS

NASA Technical Reports Server (NTRS)

Morisette, Jeffrey T.; Pinzon, Jorge E.; Brown, Molly E.; Tucker, Jim; Justice, Christopher O.

2004-01-01

The paper will address Theme 7: Multi-sensor opportunities for VEGETATION. We present analysis of a long-term vegetation record derived from three moderate resolution sensors: AVHRR, VEGETATION, and MODIS. While empirically based manipulation can ensure agreement between the three data sets, there is a need to validate the series. This paper uses atmospherically corrected ETM+ data available over the EOS Land Validation Core Sites as an independent data set with which to compare the time series. We use ETM+ data from 15 globally distributed sites, 7 of which contain repeat coverage in time. These high-resolution data are compared to the values of each sensor by spatially aggregating the ETM+ to each specific sensors' spatial coverage. The aggregated ETM+ value provides a point estimate for a specific site on a specific date. The standard deviation of that point estimate is used to construct a confidence interval for that point estimate. The values from each moderate resolution sensor are then evaluated with respect to that confident interval. Result show that AVHRR, VEGETATION, and MODIS data can be combined to assess temporal uncertainties and address data continuity issues and that the atmospherically corrected ETM+ data provide an independent source with which to compare that record. The final product is a consistent time series climate record that links historical observations to current and future measurements.

High Resolution ECG for Evaluation of QT Interval Variability during Exposure to Acute Hypoxia

NASA Technical Reports Server (NTRS)

Zupet, P.; Finderle, Z.; Schlegel, Todd T.; Starc, V.

2010-01-01

Ventricular repolarization instability as quantified by the index of QT interval variability (QTVI) is one of the best predictors for risk of malignant ventricular arrhythmias and sudden cardiac death. Because it is difficult to appropriately monitor early signs of organ dysfunction at high altitude, we investigated whether high resolution advanced ECG (HR-ECG) analysis might be helpful as a non-invasive and easy-to-use tool for evaluating the risk of cardiac arrhythmias during exposure to acute hypoxia. 19 non-acclimatized healthy trained alpinists (age 37, 8 plus or minus 4,7 years) participated in the study. Five-minute high-resolution 12-lead electrocardiograms (ECGs) were recorded (Cardiosoft) in each subject at rest in the supine position breathing room air and then after breathing 12.5% oxygen for 30 min. For beat-to-beat RR and QT variability, the program of Starc was utilized to derive standard time domain measures such as root mean square of the successive interval difference (rMSSD) of RRV and QTV, the corrected QT interval (QTc) and the QTVI in lead II. Changes were evaluated with paired-samples t-test with p-values less than 0.05 considered statistically significant. As expected, the RR interval and its variability both decreased with increasing altitude, with p = 0.000 and p = 0.005, respectively. Significant increases were found in both the rMSSDQT and the QTVI in lead II, with p = 0.002 and p = 0.003, respectively. There was no change in QTc interval length (p = non significant). QT variability parameters may be useful for evaluating changes in ventricular repolarization caused by hypoxia. These changes might be driven by increases in sympathetic nervous system activity at ventricular level.

Real-time RT-PCR high-resolution melting curve analysis and multiplex RT-PCR to detect and differentiate grapevine leafroll-associated virus 3 variant groups I, II, III and VI.

PubMed

Bester, Rachelle; Jooste, Anna E C; Maree, Hans J; Burger, Johan T

2012-09-27

Grapevine leafroll-associated virus 3 (GLRaV-3) is the main contributing agent of leafroll disease worldwide. Four of the six GLRaV-3 variant groups known have been found in South Africa, but their individual contribution to leafroll disease is unknown. In order to study the pathogenesis of leafroll disease, a sensitive and accurate diagnostic assay is required that can detect different variant groups of GLRaV-3. In this study, a one-step real-time RT-PCR, followed by high-resolution melting (HRM) curve analysis for the simultaneous detection and identification of GLRaV-3 variants of groups I, II, III and VI, was developed. A melting point confidence interval for each variant group was calculated to include at least 90% of all melting points observed. A multiplex RT-PCR protocol was developed to these four variant groups in order to assess the efficacy of the real-time RT-PCR HRM assay. A universal primer set for GLRaV-3 targeting the heat shock protein 70 homologue (Hsp70h) gene of GLRaV-3 was designed that is able to detect GLRaV-3 variant groups I, II, III and VI and differentiate between them with high-resolution melting curve analysis. The real-time RT-PCR HRM and the multiplex RT-PCR were optimized using 121 GLRaV-3 positive samples. Due to a considerable variation in melting profile observed within each GLRaV-3 group, a confidence interval of above 90% was calculated for each variant group, based on the range and distribution of melting points. The intervals of groups I and II could not be distinguished and a 95% joint confidence interval was calculated for simultaneous detection of group I and II variants. An additional primer pair targeting GLRaV-3 ORF1a was developed that can be used in a subsequent real-time RT-PCR HRM to differentiate between variants of groups I and II. Additionally, the multiplex RT-PCR successfully validated 94.64% of the infections detected with the real-time RT-PCR HRM. The real-time RT-PCR HRM provides a sensitive, automated and rapid tool to detect and differentiate different variant groups in order to study the epidemiology of leafroll disease.

β-hCG resolution times during expectant management of tubal ectopic pregnancies.

PubMed

Mavrelos, D; Memtsa, M; Helmy, S; Derdelis, G; Jauniaux, E; Jurkovic, D

2015-05-21

A subset of women with a tubal ectopic pregnancy can be safely managed expectantly. Expectant management involves a degree of disruption with hospital visits to determine serum β-hCG (β-human chorionic gonadotrophin) concentration until the pregnancy test becomes negative and expectant management is considered complete. The length of time required for the pregnancy test to become negative and the parameters that influence this interval have not been described. Information on the likely length of follow up would be useful for women considering expectant management of their tubal ectopic pregnancy. This was a retrospective study at a tertiary referral center in an inner city London Hospital. We included women who were diagnosed with a tubal ectopic pregnancy by transvaginal ultrasound between March 2009 and March 2014. During the study period 474 women were diagnosed with a tubal ectopic pregnancy and 256 (54 %) of them fulfilled our management criteria for expectant management. A total of 158 (33 %) women had successful expectant management and in those cases we recorded the diameter of the ectopic pregnancy (mm), the maximum serum β-hCG (IU/L) and levels during follow up until resolution as well as the interval to resolution (days). The median interval from maximum serum β-hCG concentration to resolution was 18.0 days (IQR 11.0-28.0). The maximum serum β-hCG concentration and the rate of decline of β-hCG were independently associated with the length of follow up. Women's age and size of ectopic pregnancy did not have significant effects on the length of follow up. Women undergoing expectant management of ectopic pregnancy can be informed that the likely length of follow up is under 3 weeks and that it positively correlates with initial β-hCG level at the time of diagnosis.

Post-partum recovery course in patients with gestational hypertension and pre-eclampsia.

PubMed

Mikami, Yukiko; Takagi, Kenjiro; Itaya, Yukiko; Ono, Yoshihisa; Matsumura, Hideyoshi; Takai, Yasushi; Seki, Hiroyuki

2014-04-01

We examined the post-partum recovery course in patients with pre-eclampsia (PE) and gestational hypertension (GH) and evaluated the associated factors. In a retrospective review of 145 patients with GH or PE who gave birth between 1 January 2008 and 30 October 2011 at our institution, there were 125 PE and 20 GH cases. Data collected included the gestational age at initial examination and delivery, delivery mode, time for normalization of blood pressure (BP), and time until resolution of proteinuria in PE patients. Comparisons were made between singleton and multiple pregnancies, onset (early, <32 weeks; late, ≥ 32 weeks) and fetal growth restriction in singleton pregnancies. The mean interval for normalization of BP was 41.8 ± 29.4 days (median, 31.5). The mean interval for resolution of proteinuria was 30.0 ± 39.6 days (median, 27.0). Ninety percent of patients required 77 and 60 days to recover from hypertension and proteinuria, respectively. The time for BP normalization was longer in the early-onset group. The time for resolution of proteinuria was not affected by any factor examined. A post-partum observation period of 12 weeks is acceptable for differentiating PE and GH from chronic hypertension or renal disease. GH severity did not affect the recovery period, but proteinuria severity did. Onset time was a factor influencing the recovery from PE and GH. © 2014 The Authors. Journal of Obstetrics and Gynaecology Research © 2014 Japan Society of Obstetrics and Gynecology.

Personalized glucose-insulin model based on signal analysis.

PubMed

Goede, Simon L; de Galan, Bastiaan E; Leow, Melvin Khee Shing

2017-04-21

Glucose plasma measurements for diabetes patients are generally presented as a glucose concentration-time profile with 15-60min time scale intervals. This limited resolution obscures detailed dynamic events of glucose appearance and metabolism. Measurement intervals of 15min or more could contribute to imperfections in present diabetes treatment. High resolution data from mixed meal tolerance tests (MMTT) for 24 type 1 and type 2 diabetes patients were used in our present modeling. We introduce a model based on the physiological properties of transport, storage and utilization. This logistic approach follows the principles of electrical network analysis and signal processing theory. The method mimics the physiological equivalent of the glucose homeostasis comprising the meal ingestion, absorption via the gastrointestinal tract (GIT) to the endocrine nexus between the liver, pancreatic alpha and beta cells. This model demystifies the metabolic 'black box' by enabling in silico simulations and fitting of individual responses to clinical data. Five-minute intervals MMTT data measured from diabetic subjects result in two independent model parameters that characterize the complete glucose system response at a personalized level. From the individual data measurements, we obtain a model which can be analyzed with a standard electrical network simulator for diagnostics and treatment optimization. The insulin dosing time scale can be accurately adjusted to match the individual requirements of characterized diabetic patients without the physical burden of treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Note: Tandem Kirkpatrick-Baez microscope with sixteen channels for high-resolution laser-plasma diagnostics

NASA Astrophysics Data System (ADS)

Yi, Shengzhen; Zhang, Zhe; Huang, Qiushi; Zhang, Zhong; Wang, Zhanshan; Wei, Lai; Liu, Dongxiao; Cao, Leifeng; Gu, Yuqiu

2018-03-01

Multi-channel Kirkpatrick-Baez (KB) microscopes, which have better resolution and collection efficiency than pinhole cameras, have been widely used in laser inertial confinement fusion to diagnose time evolution of the target implosion. In this study, a tandem multi-channel KB microscope was developed to have sixteen imaging channels with the precise control of spatial resolution and image intervals. This precise control was created using a coarse assembly of mirror pairs with high-accuracy optical prisms, followed by precise adjustment in real-time x-ray imaging experiments. The multilayers coated on the KB mirrors were designed to have substantially the same reflectivity to obtain a uniform brightness of different images for laser-plasma temperature analysis. The study provides a practicable method to achieve the optimum performance of the microscope for future high-resolution applications in inertial confinement fusion experiments.

Picosecond Resolution Time-to-Digital Converter Using Gm-C Integrator and SAR-ADC

NASA Astrophysics Data System (ADS)

Xu, Zule; Miyahara, Masaya; Matsuzawa, Akira

2014-04-01

A picosecond resolution time-to-digital converter (TDC) is presented. The resolution of a conventional delay chain TDC is limited by the delay of a logic buffer. Various types of recent TDCs are successful in breaking this limitation, but they require a significant calibration effort to achieve picosecond resolution with a sufficient linear range. To address these issues, we propose a simple method to break the resolution limitation without any calibration: a Gm-C integrator followed by a successive approximation register analog-to-digital converter (SAR-ADC). This translates the time interval into charge, and then the charge is quantized. A prototype chip was fabricated in 90 nm CMOS. The measurement results reveal a 1 ps resolution, a -0.6/0.7 LSB differential nonlinearity (DNL), a -1.1/2.3 LSB integral nonlinearity (INL), and a 9-bit range. The measured 11.74 ps single-shot precision is caused by the noise of the integrator. We analyze the noise of the integrator and propose an improved front-end circuit to reduce this noise. The proposal is verified by simulations showing the maximum single-shot precision is less than 1 ps. The proposed front-end circuit can also diminish the mismatch effects.

Time-Resolved Molecular Characterization of Limonene/Ozone Aerosol using High-Resolution Electrospray Ionization Mass Spectrometry

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

Bateman, Adam P.; Nizkorodov, Serguei; Laskin, Julia

2009-09-09

Molecular composition of limonene/O3 secondary organic aerosol (SOA) was investigated using high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) as a function of reaction time. SOA was generated by ozonation of D-limonene in a reaction chamber and sampled at different time intervals using a cascade impactor. The SOA samples were extracted into acetonitrile and analyzed using a HR-ESI-MS instrument with a resolving power of 100,000 (m/Δm). The resulting mass spectra provided detailed information about the extent of oxidation inferred from the O:C ratios, double bond equivalency (DBE) factors, and aromaticity indexes (AI) in hundreds of identified individual SOA species.

eMODIS Expedited: Overview of a Near Real Time MODIS Production System for Operational Vegetation Monitoring

NASA Astrophysics Data System (ADS)

Jenkerson, C.; Meyer, D. J.; Werpy, J.; Evenson, K.; Merritt, M.

2010-12-01

The expedited MODIS, or eMODIS production system derives near-real time Normalized Difference Vegetation Index (NDVI) from Moderate Resolution Imaging Spectroradiometer (MODIS) surface reflectance provided by the Land and Atmosphere Near-real time Capability for EOS (LANCE). There are currently three regions covered by this U.S. Geological Survey (USGS) capability, including the continental U.S., Africa, and the Central America/Caribbean regions. Each of the eMODIS production streams is configured to output its data in map projections, compositing intervals, spatial resolutions, and file formats specific to its region and user community. The challenges of processing 1,000-meter, 500-m, and especially 250-m products by midnight on the last day of a product interval have been met with increasingly effective software and system architecture. An anonymous file transfer protocol (FTP) distribution site (ftp://emodisftp.cr.usgs.gov/eMODIS) allows users direct access to eMODIS NDVI products for operational (near-real time) monitoring of vegetation conditions like drought, crop failure, insect infestation, and other threats, thus supporting subsequent early warning of famine and the targeting of vulnerable populations for insecure food situations.

Monitoring Seasonal Evapotranspiration in Vulnerable Agriculture using Time Series VHSR Satellite Data

NASA Astrophysics Data System (ADS)

Dalezios, Nicolas; Spyropoulos, Nicos V.; Tarquis, Ana M.

2015-04-01

The research work stems from the hypothesis that it is possible to perform an estimation of seasonal water needs of olive tree farms under drought periods by cross correlating high spatial, spectral and temporal resolution (~monthly) of satellite data, acquired at well defined time intervals of the phenological cycle of crops, with ground-truth information simultaneously applied during the image acquisitions. The present research is for the first time, demonstrating the coordinated efforts of space engineers, satellite mission control planners, remote sensing scientists and ground teams to record at specific time intervals of the phenological cycle of trees from ground "zero" and from 770 km above the Earth's surface, the status of plants for subsequent cross correlation and analysis regarding the estimation of the seasonal evapotranspiration in vulnerable agricultural environment. The ETo and ETc derived by Penman-Montieth equation and reference Kc tables, compared with new ETd using the Kc extracted from the time series satellite data. Several vegetation indices were also used especially the RedEdge and the chlorophyll one based on WorldView-2 RedEdge and second NIR bands to relate the tree status with water and nutrition needs. Keywords: Evapotransipration, Very High Spatial Resolution - VHSR, time series, remote sensing, vulnerability, agriculture, vegetation indeces.

A TCAS-II Resolution Advisory Detection Algorithm

NASA Technical Reports Server (NTRS)

Munoz, Cesar; Narkawicz, Anthony; Chamberlain, James

2013-01-01

The Traffic Alert and Collision Avoidance System (TCAS) is a family of airborne systems designed to reduce the risk of mid-air collisions between aircraft. TCASII, the current generation of TCAS devices, provides resolution advisories that direct pilots to maintain or increase vertical separation when aircraft distance and time parameters are beyond designed system thresholds. This paper presents a mathematical model of the TCASII Resolution Advisory (RA) logic that assumes accurate aircraft state information. Based on this model, an algorithm for RA detection is also presented. This algorithm is analogous to a conflict detection algorithm, but instead of predicting loss of separation, it predicts resolution advisories. It has been formally verified that for a kinematic model of aircraft trajectories, this algorithm completely and correctly characterizes all encounter geometries between two aircraft that lead to a resolution advisory within a given lookahead time interval. The RA detection algorithm proposed in this paper is a fundamental component of a NASA sense and avoid concept for the integration of Unmanned Aircraft Systems in civil airspace.

Flood Mapping in the Lower Mekong River Basin Using Daily MODIS Observations

NASA Technical Reports Server (NTRS)

Fayne, Jessica V.; Bolten, John D.; Doyle, Colin S.; Fuhrmann, Sven; Rice, Matthew T.; Houser, Paul R.; Lakshmi, Venkat

2017-01-01

In flat homogenous terrain such as in Cambodia and Vietnam, the monsoon season brings significant and consistent flooding between May and November. To monitor flooding in the Lower Mekong region, the near real-time NASA Flood Extent Product (NASA-FEP) was developed using seasonal normalized difference vegetation index (NDVI) differences from the 250 m resolution Moderate Resolution Imaging Spectroradiometer (MODIS) sensor compared to daily observations. The use of a percentage change interval classification relating to various stages of flooding reduces might be confusing to viewers or potential users, and therefore reducing the product usage. To increase the product usability through simplification, the classification intervals were compared with other commonly used change detection schemes to identify the change classification scheme that best delineates flooded areas. The percentage change method used in the NASA-FEP proved to be helpful in delineating flood boundaries compared to other change detection methods. The results of the accuracy assessments indicate that the -75% NDVI change interval can be reclassified to a descriptive 'flood' classification. A binary system was used to simplify the interpretation of the NASA-FEP by removing extraneous information from lower interval change classes.

Solar Cycle Driven Environmental Changes on Decadal to Centennial Scale of Late Miocene Lake Sediments (tortonian, Lake Pannon, Central Europe)

NASA Astrophysics Data System (ADS)

Piller, W. E.; Kern, A. K.; Harzhauser, M.; Soliman, A.; Mandic, O.

2012-12-01

High time resolution is a key issue in reconstructing past climate systems. This is of particular importance when searching for model predictions of future climate change, such as the warm Late Miocene. For this study we selected Lake Pannon, a paleo-ancient, alkaline, brackish lake in Europe during the Tortonian (early Late Miocene). On a continuous sediment core including the interval from ca. 10.5 - 10.4 Ma we show the power of high resolution multiproxy analyses for reconstructing paleoclimatology on a decadal scale over several millennia of Late Miocene time. To demonstrate this high-resolution interpretation we selected a core from the western margin of Lake Pannon and studied it in respect to 2 different time resolutions. A continuous 6-m-core clearly displays regular fluctuations and modulations within three different environmental proxies (natural gamma radiation, magnetic susceptibility, total abundance of ostracods). Lomb-Scargle and REDFIT periodograms next to wavelet spectra of all data sets reveal distinct frequencies. Only few of these are deciphered in all proxy data sets at the same power, while some occur only in two or one proxies. A higher resolution study was conducted on a 1.5-m-long core interval based on pollen and dinoflagellate cysts, ostracod abundance, carbon and sulfur contents as well as magnetic susceptibility and natural gamma radiation. Based on an already established age model the study covers about two millennia of Late Miocene time with a resolution of ~13.7 years per sample. No major ecological turnovers are expected in respect to this very short interval. Thus, the pollen record suggests rather stable wetland vegetation with a forested hinterland. Shifts in the spectra can be mainly attributed to variations in transport mechanism, represented by few phases of fluvial input but mainly by changes in wind intensity and probably also wind direction. Even within this short time span, dinoflagellates document rapid changes between oligotrophic and eutrophic conditions, which are frequently coupled with lake stratification and dysoxic bottom waters. These phases prevented ostracods and molluscs from settling and fostered the activity of sulfur bacteria. Several of the studied proxies reveal iterative patterns. To compare and detect these repetitive signals REDFIT spectra were generated and Gaussian filters were applied. The resulting cycles correspond to the lower and upper Gleissberg, the de Vries/Suess, the unnamed 500-year, 1000-year 1,500-year and the Hallstatt cycles. To test the solar-forcing-hypothesis, our data have been compared with those from a Holocene isotope dataset. Our data represent a first unequivocal detection of solar cycles in pre-Pleistocene sediments.

Distribution of cattle grazing in a northeastern Oregon riparian pasture

USDA-ARS?s Scientific Manuscript database

Livestock grazing of a northeastern Oregon riparian pasture was monitored using high-frequency GPS tracking of cattle and high-resolution aerial photography. Tracking collars recorded positions, velocity, date, and time at 1-sec intervals. Areas where animals rested and moved were identified and re...

Data system for multiplexed water-current meters

NASA Technical Reports Server (NTRS)

Ramsey, C. R.

1977-01-01

Flow rates at 32 flood plain locations are measured simultaneously by single digital logic unit with high noise immunity. Water flowing through pygmy current meters rotates element that closes electrical contact once every resolution, so flow rate is measured by counting number of closures in time interval.

Paleomagnetic and rock magnetic study of IODP Site U1408 in the Northwest Atlantic - toward the high-resolution relative paleointensity estimate during the middle Eocene

NASA Astrophysics Data System (ADS)

Yamamoto, Y.; Yamazaki, T.; Oda, H.

2015-12-01

We have conducted paleomagnetic and rock magnetic measurements on the sedimentary sections recovered from Integrated Ocean Drilling Program (IODP) Site U1408 in the Northwest Atlantic, off Newfoundland. The measurements were done on u-channel samples using a pass-through superconducting rock magnetometer in a manner that remanent magnetizations (natural, anhysteretic and isothermal remanent magnetizations: NRM, ARM and IRM) were subjected to stepwise alternating field (AF) demagnetizations up to 80 mT and are measured with 1 cm spacing at each step.The characteristic remanent magnetization (ChRM) was resolved after AF demagnetization of 20-30 mT for most of the studied interval. As a result, we could identify several polarity reversals which were able to be correlated with the geomagnetic polarity time scale by Gradstein et al. (2012) (Geologic Time Scale 2012), with referring the shipboard biostratigraphy (Norris et al., 2014). The interval at ~ 33-157 mcd (meter composite depth) was interpreted to cover the Chrons C18n.1n to C20n with missing Chron C19n because of the somewhat ambiguous magnetic signals at the interval at ~ 70-110 mcd. The correlation provided an age model inferring sedimentation rate of about 2-4 cm/kyr during these chrons.There is the interval that shows relatively constant ARM and IRM intensities as well as ratios of ARM to IRM (ARM/IRM): the interval at ~ 37-90 mcd resulted in ARM intensity of 0.2-0.4 A/m, IRM intensity of 1-2 A/m and ARM/IRM of 0.17-0.20. This interval corresponds to the Chron C18 and the estimated sedimentation rate of the interval is ~ 2 cm/kyr. It is expected that high-resolution relative paleointensity estimate during the middle Eocene is potentially possible. We will report a preliminary estimate.

High-resolution Bent-crystal Spectrometer for the Ultra-soft X-ray Region

DOE R&D Accomplishments Database

Beiersdorfer, P.; von Goeler, S.; Bitter, M.; Hill, K. W.; Hulse, R. A.; Walling, R. S.

1988-10-01

A multichannel vacuum Brag-crystal spectrometer has been developed for high-resolution measurements of the line emission from tokamak plasmas in the wavelength region between 4 and 25 angstrom. The spectrometer employs a bent crystal in Johann geometry and a microchannel-plate intensified photodiode array. The instrument is capable of measuring high-resolution spectra (lambda/..delta..lambda approx. 3000) with fast time resolution (4 msec per spectrum) and good spatial resolution (3 cm). The spectral bandwidth is ..delta..lambda/lambda{sub 0} = 8 angstrom. A simple tilt mechanism allows access to different wavelength intervals. In order to illustrate the utility of the new spectrometer, time- and space-resolved measurements of the n = 3 to n = 2 spectrum of selenium from the Princeton Large Torus tokamak plasmas are presented. The data are used to determine the plasma transport parameters and to infer the radial distribution of fluorinelike, neonlike, and sodiumlike ions of selenium in the plasma. The new ultra-soft x-ray spectrometer has thus enabled us to demonstrate the utility of high-resolution L-shell spectroscopy of neonlike ions as a fusion diagnostic.

Patient navigation and time to diagnostic resolution: results for a cluster randomized trial evaluating the efficacy of patient navigation among patients with breast cancer screening abnormalities, Tampa, FL.

PubMed

Lee, Ji-Hyun; Fulp, William; Wells, Kristen J; Meade, Cathy D; Calcano, Ercilia; Roetzheim, Richard

2013-01-01

The objective of this study was to evaluate a patient navigation (PN) program that attempts to reduce the time between a breast cancer screening abnormality and definitive diagnosis among medically underserved populations of Tampa Bay, Florida. The Moffitt Patient Navigation Research Program conducted a cluster randomized design with 10 primary care clinics. Patients were navigated from time of a breast screening abnormality to diagnostic resolution. This paper examined the length of time between breast abnormality and definitive diagnosis, using a shared frailty Cox proportional hazard model to assess PN program effect. 1,039 patients were eligible for the study because of an abnormal breast cancer screening/clinical abnormality (494 navigated; 545 control). Analysis of PN effect by two time periods of resolution (0-3 months and > 3 months) showed a lagged effect of PN. For patients resolving in the first three months, the adjusted Hazard Ratio (aHR) was 0.85 (95% Confidence Interval [CI]: 0.64-1.13) suggesting that PN had no effect on resolution time during this period. Beyond three months, however, navigated patients resolved more quickly to diagnostic resolution compared with the control group (aHR 2.8, 95%CI: 1.30-6.13). The predicted aHR at 3 months was 1.2, which was not statistically significant, while PN had a significant positive effect beyond 4.7 months. PN programs may increase the timeliness of diagnostic resolution for patients with a breast cancer-related abnormality. PN did not speed diagnostic resolution during the initial three months of follow up but started to reduce time to diagnostic resolution after three months and showed a significant effect after 4.7 months. ClinicalTrials.gov NCT00375024.

High resolution in situ ultrasonic corrosion monitor

DOEpatents

Grossman, R.J.

1984-01-10

An ultrasonic corrosion monitor is provided which produces an in situ measurement of the amount of corrosion of a monitoring zone or zones of an elongate probe placed in the corrosive environment. A monitoring zone is preferably formed between the end of the probe and the junction of the zone with a lead-in portion of the probe. Ultrasonic pulses are applied to the probe and a determination made of the time interval between pulses reflected from the end of the probe and the junction referred to, both when the probe is uncorroded and while it is corroding. Corresponding electrical signals are produced and a value for the normalized transit time delay derived from these time interval measurements is used to calculate the amount of corrosion.

High resolution in situ ultrasonic corrosion monitor

DOEpatents

Grossman, Robert J.

1985-01-01

An ultrasonic corrosion monitor is provided which produces an in situ measurement of the amount of corrosion of a monitoring zone or zones of an elongate probe placed in the corrosive environment. A monitoring zone is preferably formed between the end of the probe and the junction of the zone with a lead-in portion of the probe. Ultrasonic pulses are applied to the probe and a determination made of the time interval between pulses reflected from the end of the probe and the junction referred to, both when the probe is uncorroded and while it is corroding. Corresponding electrical signals are produced and a value for the normalized transit time delay derived from these time interval measurements is used to calculate the amount of corrosion.

40 CFR 91.314 - Analyzer accuracy and specifications.

Code of Federal Regulations, 2014 CFR

2014-07-01

... deflection should generally not be used. (2) Some high resolution read-out systems, such as computers, data...-second time interval. (b) Operating procedure for analyzers and sampling system. Follow the start-up and... systems may be used provided that additional calibrations are made to ensure the accuracy of the...

A cloud masking algorithm for EARLINET lidar systems

NASA Astrophysics Data System (ADS)

Binietoglou, Ioannis; Baars, Holger; D'Amico, Giuseppe; Nicolae, Doina

2015-04-01

Cloud masking is an important first step in any aerosol lidar processing chain as most data processing algorithms can only be applied on cloud free observations. Up to now, the selection of a cloud-free time interval for data processing is typically performed manually, and this is one of the outstanding problems for automatic processing of lidar data in networks such as EARLINET. In this contribution we present initial developments of a cloud masking algorithm that permits the selection of the appropriate time intervals for lidar data processing based on uncalibrated lidar signals. The algorithm is based on a signal normalization procedure using the range of observed values of lidar returns, designed to work with different lidar systems with minimal user input. This normalization procedure can be applied to measurement periods of only few hours, even if no suitable cloud-free interval exists, and thus can be used even when only a short period of lidar measurements is available. Clouds are detected based on a combination of criteria including the magnitude of the normalized lidar signal and time-space edge detection performed using the Sobel operator. In this way the algorithm avoids misclassification of strong aerosol layers as clouds. Cloud detection is performed using the highest available time and vertical resolution of the lidar signals, allowing the effective detection of low-level clouds (e.g. cumulus humilis). Special attention is given to suppress false cloud detection due to signal noise that can affect the algorithm's performance, especially during day-time. In this contribution we present the details of algorithm, the effect of lidar characteristics (space-time resolution, available wavelengths, signal-to-noise ratio) to detection performance, and highlight the current strengths and limitations of the algorithm using lidar scenes from different lidar systems in different locations across Europe.

Validation of mercury tip-switch and accelerometer activity sensors for identifying resting and active behavior in bears

USGS Publications Warehouse

Jasmine Ware,; Rode, Karyn D.; Pagano, Anthony M.; Bromaghin, Jeffrey F.; Robbins, Charles T.; Joy Erlenbach,; Shannon Jensen,; Amy Cutting,; Nicole Nicassio-Hiskey,; Amy Hash,; Owen, Megan A.; Heiko Jansen,

2015-01-01

Activity sensors are often included in wildlife transmitters and can provide information on the behavior and activity patterns of animals remotely. However, interpreting activity-sensor data relative to animal behavior can be difficult if animals cannot be continuously observed. In this study, we examined the performance of a mercury tip-switch and a tri-axial accelerometer housed in collars to determine whether sensor data can be accurately classified as resting and active behaviors and whether data are comparable for the 2 sensor types. Five captive bears (3 polar [Ursus maritimus] and 2 brown [U. arctos horribilis]) were fitted with a collar specially designed to internally house the sensors. The bears’ behaviors were recorded, classified, and then compared with sensor readings. A separate tri-axial accelerometer that sampled continuously at a higher frequency and provided raw acceleration values from 3 axes was also mounted on the collar to compare with the lower resolution sensors. Both accelerometers more accurately identified resting and active behaviors at time intervals ranging from 1 minute to 1 hour (≥91.1% accuracy) compared with the mercury tip-switch (range = 75.5–86.3%). However, mercury tip-switch accuracy improved when sampled at longer intervals (e.g., 30–60 min). Data from the lower resolution accelerometer, but not the mercury tip-switch, accurately predicted the percentage of time spent resting during an hour. Although the number of bears available for this study was small, our results suggest that these activity sensors can remotely identify resting versus active behaviors across most time intervals. We recommend that investigators consider both study objectives and the variation in accuracy of classifying resting and active behaviors reported here when determining sampling interval.

Automation for Air Traffic Control: The Rise of a New Discipline

NASA Technical Reports Server (NTRS)

Erzberger, Heinz; Tobias, Leonard (Technical Monitor)

1997-01-01

The current debate over the concept of Free Flight has renewed interest in automated conflict detection and resolution in the enroute airspace. An essential requirement for effective conflict detection is accurate prediction of trajectories. Trajectory prediction is, however, an inexact process which accumulates errors that grow in proportion to the length of the prediction time interval. Using a model of prediction errors for the trajectory predictor incorporated in the Center-TRACON Automation System (CTAS), a computationally fast algorithm for computing conflict probability has been derived. Furthermore, a method of conflict resolution has been formulated that minimizes the average cost of resolution, when cost is defined as the increment in airline operating costs incurred in flying the resolution maneuver. The method optimizes the trade off between early resolution at lower maneuver costs but higher prediction error on the one hand and late resolution with higher maneuver costs but lower prediction errors on the other. The method determines both the time to initiate the resolution maneuver as well as the characteristics of the resolution trajectory so as to minimize the cost of the resolution. Several computational examples relevant to the design of a conflict probe that can support user-preferred trajectories in the enroute airspace will be presented.

Assessment of a vertical high-resolution distributed-temperature-sensing system in a shallow thermohaline environment

NASA Astrophysics Data System (ADS)

Suárez, F.; Aravena, J. E.; Hausner, M. B.; Childress, A. E.; Tyler, S. W.

2011-01-01

In shallow thermohaline-driven lakes it is important to measure temperature on fine spatial and temporal scales to detect stratification or different hydrodynamic regimes. Raman spectra distributed temperature sensing (DTS) is an approach available to provide high spatial and temporal temperature resolution. A vertical high-resolution DTS system was constructed to overcome the problems of typical methods used in the past, i.e., without disturbing the water column, and with resistance to corrosive environments. This system monitors the temperature profile each 1.1 cm vertically and in time averages as small as 10 s. Temperature resolution as low as 0.035 °C is obtained when the data are collected at 5-min intervals. The vertical high-resolution DTS system is used to monitor the thermal behavior of a salt-gradient solar pond, which is an engineered shallow thermohaline system that allows collection and storage of solar energy for a long period of time. This paper describes a method to quantitatively assess accuracy, precision and other limitations of DTS systems to fully utilize the capacity of this technology. It also presents, for the first time, a method to manually calibrate temperatures along the optical fiber.

More accurate, calibrated bootstrap confidence intervals for correlating two autocorrelated climate time series

NASA Astrophysics Data System (ADS)

Olafsdottir, Kristin B.; Mudelsee, Manfred

2013-04-01

Estimation of the Pearson's correlation coefficient between two time series to evaluate the influences of one time depended variable on another is one of the most often used statistical method in climate sciences. Various methods are used to estimate confidence interval to support the correlation point estimate. Many of them make strong mathematical assumptions regarding distributional shape and serial correlation, which are rarely met. More robust statistical methods are needed to increase the accuracy of the confidence intervals. Bootstrap confidence intervals are estimated in the Fortran 90 program PearsonT (Mudelsee, 2003), where the main intention was to get an accurate confidence interval for correlation coefficient between two time series by taking the serial dependence of the process that generated the data into account. However, Monte Carlo experiments show that the coverage accuracy for smaller data sizes can be improved. Here we adapt the PearsonT program into a new version called PearsonT3, by calibrating the confidence interval to increase the coverage accuracy. Calibration is a bootstrap resampling technique, which basically performs a second bootstrap loop or resamples from the bootstrap resamples. It offers, like the non-calibrated bootstrap confidence intervals, robustness against the data distribution. Pairwise moving block bootstrap is used to preserve the serial correlation of both time series. The calibration is applied to standard error based bootstrap Student's t confidence intervals. The performances of the calibrated confidence intervals are examined with Monte Carlo simulations, and compared with the performances of confidence intervals without calibration, that is, PearsonT. The coverage accuracy is evidently better for the calibrated confidence intervals where the coverage error is acceptably small (i.e., within a few percentage points) already for data sizes as small as 20. One form of climate time series is output from numerical models which simulate the climate system. The method is applied to model data from the high resolution ocean model, INALT01 where the relationship between the Agulhas Leakage and the North Brazil Current is evaluated. Preliminary results show significant correlation between the two variables when there is 10 year lag between them, which is more or less the time that takes the Agulhas Leakage water to reach the North Brazil Current. Mudelsee, M., 2003. Estimating Pearson's correlation coefficient with bootstrap confidence interval from serially dependent time series. Mathematical Geology 35, 651-665.

A streak camera based fiber optic pulsed polarimetry technique for magnetic sensing to sub-mm resolution.

PubMed

Smith, R J; Weber, T E

2016-11-01

The technique of fiber optic pulsed polarimetry, which provides a distributed (local) measurement of the magnetic field along an optical fiber, has been improved to the point where, for the first time, photocathode based optical detection of backscatter is possible with sub-mm spatial resolutions. This has been realized through the writing of an array of deterministic fiber Bragg gratings along the fiber, a so-called backscatter-tailored optical fiber, producing a 34 000-fold increase in backscatter levels over Rayleigh. With such high backscatter levels, high repetition rate lasers are now sufficiently bright to allow near continuous field sensing in both space and time with field resolutions as low as 0.005 T and as high as 170 T over a ∼mm interval given available fiber materials.

A compendium of fossil marine animal families, 2nd edition

NASA Technical Reports Server (NTRS)

Sepkoski, J. J. Jr; Sepkoski JJ, J. r. (Principal Investigator)

1992-01-01

A comprehensive listing of 4075 taxonomic families of marine animals known from the fossil record is presented. This listing covers invertebrates, vertebrates, and animal-like protists, gives time intervals of apparent origination and extinction, and provides literature sources for these data. The time intervals are mostly 81 internationally recognized stratigraphic stages; more than half of the data are resolved to one of 145 substage divisions, providing more highly resolved data for studies of taxic macroevolution. Families are classified by order, class, and phylum, reflecting current classifications in the published literature. This compendium is a new edition of the 1982 publication, correcting errors and presenting greater stratigraphic resolution and more current ideas about acceptable families and their classification.

Effect of image resolution manipulation in rearfoot angle measurements obtained with photogrammetry

PubMed Central

Sacco, I.C.N.; Picon, A.P.; Ribeiro, A.P.; Sartor, C.D.; Camargo-Junior, F.; Macedo, D.O.; Mori, E.T.T.; Monte, F.; Yamate, G.Y.; Neves, J.G.; Kondo, V.E.; Aliberti, S.

2012-01-01

The aim of this study was to investigate the influence of image resolution manipulation on the photogrammetric measurement of the rearfoot static angle. The study design was that of a reliability study. We evaluated 19 healthy young adults (11 females and 8 males). The photographs were taken at 1536 pixels in the greatest dimension, resized into four different resolutions (1200, 768, 600, 384 pixels) and analyzed by three equally trained examiners on a 96-pixels per inch (ppi) screen. An experienced physiotherapist marked the anatomic landmarks of rearfoot static angles on two occasions within a 1-week interval. Three different examiners had marked angles on digital pictures. The systematic error and the smallest detectable difference were calculated from the angle values between the image resolutions and times of evaluation. Different resolutions were compared by analysis of variance. Inter- and intra-examiner reliability was calculated by intra-class correlation coefficients (ICC). The rearfoot static angles obtained by the examiners in each resolution were not different (P > 0.05); however, the higher the image resolution the better the inter-examiner reliability. The intra-examiner reliability (within a 1-week interval) was considered to be unacceptable for all image resolutions (ICC range: 0.08-0.52). The whole body image of an adult with a minimum size of 768 pixels analyzed on a 96-ppi screen can provide very good inter-examiner reliability for photogrammetric measurements of rearfoot static angles (ICC range: 0.85-0.92), although the intra-examiner reliability within each resolution was not acceptable. Therefore, this method is not a proper tool for follow-up evaluations of patients within a therapeutic protocol. PMID:22911379

Effect of image resolution manipulation in rearfoot angle measurements obtained with photogrammetry.

PubMed

Sacco, I C N; Picon, A P; Ribeiro, A P; Sartor, C D; Camargo-Junior, F; Macedo, D O; Mori, E T T; Monte, F; Yamate, G Y; Neves, J G; Kondo, V E; Aliberti, S

2012-09-01

The aim of this study was to investigate the influence of image resolution manipulation on the photogrammetric measurement of the rearfoot static angle. The study design was that of a reliability study. We evaluated 19 healthy young adults (11 females and 8 males). The photographs were taken at 1536 pixels in the greatest dimension, resized into four different resolutions (1200, 768, 600, 384 pixels) and analyzed by three equally trained examiners on a 96-pixels per inch (ppi) screen. An experienced physiotherapist marked the anatomic landmarks of rearfoot static angles on two occasions within a 1-week interval. Three different examiners had marked angles on digital pictures. The systematic error and the smallest detectable difference were calculated from the angle values between the image resolutions and times of evaluation. Different resolutions were compared by analysis of variance. Inter- and intra-examiner reliability was calculated by intra-class correlation coefficients (ICC). The rearfoot static angles obtained by the examiners in each resolution were not different (P > 0.05); however, the higher the image resolution the better the inter-examiner reliability. The intra-examiner reliability (within a 1-week interval) was considered to be unacceptable for all image resolutions (ICC range: 0.08-0.52). The whole body image of an adult with a minimum size of 768 pixels analyzed on a 96-ppi screen can provide very good inter-examiner reliability for photogrammetric measurements of rearfoot static angles (ICC range: 0.85-0.92), although the intra-examiner reliability within each resolution was not acceptable. Therefore, this method is not a proper tool for follow-up evaluations of patients within a therapeutic protocol.

Preliminary experience using dynamic MRI at 3.0 Tesla for evaluation of soft tissue tumors.

PubMed

Park, Michael Yong; Jee, Won-Hee; Kim, Sun Ki; Lee, So-Yeon; Jung, Joon-Yong

2013-01-01

We aimed to evaluate the use of dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) at 3.0 T for differentiating the benign from malignant soft tissue tumors. Also we aimed to assess whether the shorter length of DCE-MRI protocols are adequate, and to evaluate the effect of temporal resolution. Dynamic contrast-enhanced magnetic resonance imaging, at 3.0 T with a 1 second temporal resolution in 13 patients with pathologically confirmed soft tissue tumors, was analyzed. Visual assessment of time-signal curves, subtraction images, maximal relative enhancement at the first (maximal peak enhancement [Emax]/1) and second (Emax/2) minutes, Emax, steepest slope calculated by using various time intervals (5, 30, 60 seconds), and the start of dynamic enhancement were analyzed. The 13 tumors were comprised of seven benign and six malignant soft tissue neoplasms. Washout on time-signal curves was seen on three (50%) malignant tumors and one (14%) benign one. The most discriminating DCE-MRI parameter was the steepest slope calculated, by using at 5-second intervals, followed by Emax/1 and Emax/2. All of the steepest slope values occurred within 2 minutes of the dynamic study. Start of dynamic enhancement did not show a significant difference, but no malignant tumor rendered a value greater than 14 seconds. The steepest slope and early relative enhancement have the potential for differentiating benign from malignant soft tissue tumors. Short-length rather than long-length DCE-MRI protocol may be adequate for our purpose. The steepest slope parameters require a short temporal resolution, while maximal peak enhancement parameter may be more optimal for a longer temporal resolution.

Multichannel Spectrometer of Time Distribution

NASA Astrophysics Data System (ADS)

Akindinova, E. V.; Babenko, A. G.; Vakhtel, V. M.; Evseev, N. A.; Rabotkin, V. A.; Kharitonova, D. D.

2015-06-01

For research and control of characteristics of radiation fluxes, radioactive sources in particular, for example, in paper [1], a spectrometer and methods of data measurement and processing based on the multichannel counter of time intervals of accident events appearance (impulses of particle detector) MC-2A (SPC "ASPECT") were created. The spectrometer has four independent channels of registration of time intervals of impulses appearance and correspondent amplitude and spectrometric channels for control along the energy spectra of the operation stationarity of paths of each of the channels from the detector to the amplifier. The registration of alpha-radiation is carried out by the semiconductor detectors with energy resolution of 16-30 keV. Using a spectrometer there have been taken measurements of oscillations of alpha-radiation 239-Pu flux intensity with a subsequent autocorrelative statistical analysis of the time series of readings.

Assessment of a vertical high-resolution distributed-temperature-sensing system in a shallow thermohaline environment

NASA Astrophysics Data System (ADS)

Suárez, F.; Aravena, J. E.; Hausner, M. B.; Childress, A. E.; Tyler, S. W.

2011-03-01

In shallow thermohaline-driven lakes it is important to measure temperature on fine spatial and temporal scales to detect stratification or different hydrodynamic regimes. Raman spectra distributed temperature sensing (DTS) is an approach available to provide high spatial and temporal temperature resolution. A vertical high-resolution DTS system was constructed to overcome the problems of typical methods used in the past, i.e., without disturbing the water column, and with resistance to corrosive environments. This paper describes a method to quantitatively assess accuracy, precision and other limitations of DTS systems to fully utilize the capacity of this technology, with a focus on vertical high-resolution to measure temperatures in shallow thermohaline environments. It also presents a new method to manually calibrate temperatures along the optical fiber achieving significant improved resolution. The vertical high-resolution DTS system is used to monitor the thermal behavior of a salt-gradient solar pond, which is an engineered shallow thermohaline system that allows collection and storage of solar energy for a long period of time. The vertical high-resolution DTS system monitors the temperature profile each 1.1 cm vertically and in time averages as small as 10 s. Temperature resolution as low as 0.035 °C is obtained when the data are collected at 5-min intervals.

Mind the gap: temporal discrimination and dystonia.

PubMed

Sadnicka, A; Daum, C; Cordivari, C; Bhatia, K P; Rothwell, J C; Manohar, S; Edwards, M J

2017-06-01

One of the most widely studied perceptual measures of sensory dysfunction in dystonia is the temporal discrimination threshold (TDT) (the shortest interval at which subjects can perceive that there are two stimuli rather than one). However the elevated thresholds described may be due to a number of potential mechanisms as current paradigms test not only temporal discrimination but also extraneous sensory and decision-making parameters. In this study two paradigms designed to better quantify temporal processing are presented and a decision-making model is used to assess the influence of decision strategy. 22 patients with cervical dystonia and 22 age-matched controls completed two tasks (i) temporal resolution (a randomized, automated version of existing TDT paradigms) and (ii) interval discrimination (rating the length of two consecutive intervals). In the temporal resolution task patients had delayed (P = 0.021) and more variable (P = 0.013) response times but equivalent discrimination thresholds. Modelling these effects suggested this was due to an increased perceptual decision boundary in dystonia with patients requiring greater evidence before committing to decisions (P = 0.020). Patient performance on the interval discrimination task was normal. Our work suggests that previously observed abnormalities in TDT may not be due to a selective sensory deficit of temporal processing as decision-making itself is abnormal in cervical dystonia. © 2017 EAN.

Application of High- and Low-Orbiting Radio Tomography for Exploring the Ionospheric Structures on Different Scales

NASA Astrophysics Data System (ADS)

Andreeva, Elena; Padokhin, Artem; Nazarenko, Marina; Nesterov, Ivan; Tumanova, Yulia; Tereshchenko, Evgeniy; Kozharin, Maksim

2016-07-01

The methods of ionospheric radio tomography (RT) are actively developing at present. These methods are suitable for reconstructing the spatial distributions of electron density from radio signals transmitted from the navigational satellite systems and recorded by the networks of ground-based receivers. The RT systems based on the low-orbiting (LO) (Parus/Transit) navigational systems have been in operation since the early 1990s. Recently, the RT methods employing the signals from high-orbiting (HO) satellite navigational systems such as GPS/GLONASS have come into play. In our presentation, we discuss the accuracies, advantages, and limitations of LORT and HORT as well as the possibilities of their combined application fro reconstructing the structure of the ionosphere in the same region during the same time interval on the different spatiotemporal scales. The LORT reconstructions provide practically instantaneous (spanning 5-10 min) 2D snapshots of the ionosphere within a spatial interval with a length of up to a few thousand km. The vertical resolution of LORT is 25-30 km and the horizontal resolution, 15-25 km. The HORT methods are capable of reconstructing the 4D structure of the ionosphere (three spatial coordinates and time). The spatial resolution of HORT is generally not better than 100 km with a 60-20 min interval between the successive reconstructions. In the regions of dense receiving networks, the resolution can be improved to 30-50 km and the time step can be reduced to 30-10 min. In California and Japan which are covered by extremely dense receiving networks the resolution can be even higher (10-30 km) and the time interval between the reconstruction even shorter (up to 2 min). In the presentation, we discuss the LORT and HORT reconstructions of the ionosphere during different time periods of the 23rd and 24th solar cycles in the different regions of the world. We analyze the spatiotemporal features and dynamics of the ionosphere depending on the solar and geophysical conditions. Particular attention is attached to the periods of the strong geomagnetic disturbances. The stormy ionosphere is characterized by extremely sophisticated structure and rapid dynamics. Being affected by a variety of the perturbing factors, the ionospheric parameters experience striking variations which can be traced by the RT methods. The RT reconstructions revealed multi-extremal plasma structures, steep wall-like gradients of electron density, and spots of enhanced ionization. A complicated structure of the main ionization trough with its polar wall moving equatorwards was observed. In contrast to the middle and lower latitudes where the magnetic field largely shields the Earth from the energetic particle fluxes, the RT reconstructions in the northern high latitudes demonstrate the presence of localized highly ionized features and wavelike disturbances associated with the injections of corpuscular radiation into the ionosphere. We present and discuss the examples of the qualitative comparisons of the RT ionospheric images with the data on the ionizing particle fluxes measured by the DMSP satellite. The examples of RT data comparison with the ionosonde measurements are demonstrated.

Systematic vertical and lateral changes in quality and time resolution of the macrofossil record: insights from Holocene transgressive deposits, Po coastal plain, Italy

NASA Astrophysics Data System (ADS)

Azzarone, Michele; Scarponi, Daniele; Kusnerik, Kristopher; Amorosi, Alessandro; Bohacs, Kevin M.; Drexler, Tina M.; Kowalewski, Michał

2017-04-01

In siliciclastic marine settings, skeletal concentrations are a characteristic feature of transgressive intervals that provide insights into paleobiology and sequence stratigraphy. To investigate taphonomic signatures of transgressive intervals, we analyzed three cores from a Holocene depositional profile of the Po coastal plain, in northern Italy. Coupled multivariate taphonomic and bathymetric trends delineate spatial and temporal gradients in sediment starvation/bypassing, suggesting that quality and resolution of the fossil record vary predictably along the studied depositional profile. Moreover, joint consideration of taphonomic, bathymetric, and fossil density trends across the study area reveals distinctive signatures that are useful in characterizing facies associations and recognizing surfaces and intervals of sequence stratigraphic significance. Within the southern Po plain succession, taphonomic degradation of macroskeletal remains increases from proximal—nearshore to distal—offshore locations. This trend is discernible for both biologically-driven (bioerosion) and chemically/physically-driven (e.g., dissolution, abrasion) shell alterations. Compared to the up-dip (most proximal) core, the down-dip core is distinguished by shell-rich lithosomes affected by ecological condensation (co-occurrence of environmentally non-overlapping taxa) and by higher taphonomic alteration. The onshore-offshore taphonomic trend likely reflects variation in sediment-supply along the depositional profile of the Holocene Northern Adriatic shelf, with surface/near-surface residence-time of macroskeletal remains increasing down dip due to lower accumulation rates. These results indicate that, during transgressive phases, changes in sea-level (base level) are likely to produce down-dip taphonomic gradients across shelves, where the quality and resolution of the fossil record both deteriorate distally. The amino acid radiometrically calibrated dates on bivalves and the chronostratigraphic framework for this profile suggest that the high levels of taphonomic degradation observed distally developed over millennial time scales ( 8ky). The patterns documented here may be characteristic of siliciclastic-dominated depositional systems that experience high-frequency, base-level fluctuations.

Advancing the quantification of humid tropical forest cover loss with multi-resolution optical remote sensing data: Sampling & wall-to-wall mapping

NASA Astrophysics Data System (ADS)

Broich, Mark

Humid tropical forest cover loss is threatening the sustainability of ecosystem goods and services as vast forest areas are rapidly cleared for industrial scale agriculture and tree plantations. Despite the importance of humid tropical forest in the provision of ecosystem services and economic development opportunities, the spatial and temporal distribution of forest cover loss across large areas is not well quantified. Here I improve the quantification of humid tropical forest cover loss using two remote sensing-based methods: sampling and wall-to-wall mapping. In all of the presented studies, the integration of coarse spatial, high temporal resolution data with moderate spatial, low temporal resolution data enable advances in quantifying forest cover loss in the humid tropics. Imagery from the Moderate Resolution Imaging Spectroradiometer (MODIS) are used as the source of coarse spatial resolution, high temporal resolution data and imagery from the Landsat Enhanced Thematic Mapper Plus (ETM+) sensor are used as the source of moderate spatial, low temporal resolution data. In a first study, I compare the precision of different sampling designs for the Brazilian Amazon using the annual deforestation maps derived by the Brazilian Space Agency for reference. I show that sampling designs can provide reliable deforestation estimates; furthermore, sampling designs guided by MODIS data can provide more efficient estimates than the systematic design used for the United Nations Food and Agricultural Organization Forest Resource Assessment 2010. Sampling approaches, such as the one demonstrated, are viable in regions where data limitations, such as cloud contamination, limit exhaustive mapping methods. Cloud-contaminated regions experiencing high rates of change include Insular Southeast Asia, specifically Indonesia and Malaysia. Due to persistent cloud cover, forest cover loss in Indonesia has only been mapped at a 5-10 year interval using photo interpretation of single best Landsat images. Such an approach does not provide timely results, and cloud cover reduces the utility of map outputs. In a second study, I develop a method to exhaustively mine the recently opened Landsat archive for cloud-free observations and automatically map forest cover loss for Sumatra and Kalimantan for the 2000-2005 interval. In a comparison with a reference dataset consisting of 64 Landsat sample blocks, I show that my method, using per pixel time-series, provides more accurate forest cover loss maps for multiyear intervals than approaches using image composites. In a third study, I disaggregate Landsat-mapped forest cover loss, mapped over a multiyear interval, by year using annual forest cover loss maps generated from coarse spatial, high temporal resolution MODIS imagery. I further disaggregate and analyze forest cover loss by forest land use, and provinces. Forest cover loss trends show high spatial and temporal variability. These results underline the importance of annual mapping for the quantification of forest cover loss in Indonesia, specifically in the light of the developing Reducing Emissions from Deforestation and Forest Degradation in Developing Countries policy framework (REDD). All three studies highlight the advances in quantifying forest cover loss in the humid tropics made by integrating coarse spatial, high temporal resolution data with moderate spatial, low temporal resolution data. The three methods presented can be combined into an integrated monitoring strategy.

Evidence for Millennial-Scale Climate Variability in the Surface Waters Above ODP Site 980, NE Atlantic Ocean During the Last Glacial Interval (MIS 4-2)

NASA Astrophysics Data System (ADS)

Michaud, J. R.; Cullen, J. L.; McManus, J. F.; Oppo, D. W.

2004-05-01

Successful efforts to recover quality high sedimentation rate deep-sea sediment sections from the North Atlantic over the last decade have produced a number of studies demonstrating that climate instability at sub-orbital and even millennial time-scales is a pervasive component of Late Pleistocene North Atlantic climate. This is particularly true during Marine Isotope Stages (MIS) 4-2, i.e., the last glacial interval. One such high sedimentation rate section was recovered at ODP Site 980, Northeast Atlantic Ocean where sedimentation rates during MIS 4-2 exceed 15cm/kyr. Recently, we have begun to generate more detailed records from MIS 4-2 at Site 980 by reducing our sampling interval from 20 to around 2.5 cm, improving the resolution of our records an order of magnitude, from 1200-1300 to 100-200 years. 300 samples were used to generate high resolution records of changes in the input of ice-rafted detritus (IRD), along with limited data documenting changes in the relative abundance of the N. pachyderma, left coiling, which can be evaluated within the context of our previously generated lower resolution planktic and benthic oxygen isotope records used to generate our age model for this interval. Our previously published low resolution IRD record enabled us to identify Heinrich events 1-6 within the sediment interval deposited during the last glacial. Each event is characterized by IRD concentrations ranging from 500 to over 2500 lithic grains >150 microns per gram sediment. Superimposing our new high resolution IRD record reveals that Heinrich events 3,2,1 occurring at approximately 32, 23, and 17 kya, respectively, are each composed of a series of separate abrupt rapid increases in IRD concentrations approaching 1,000 grains per gram. An additional comparable event occurring at approximately 20 kya has also been identified. In the early part of the last glacial H6, H5, and H4 occurring at approximately 66, 47, and 38 kya, respectively, are recorded as much more abrupt and rapid increases in IRD concentrations to 2,000 or greater lithic grains per gram than were observed in our previous record. There are two 5 kyr intervals between H6 and H5 that contain little or no IRD. An additional abrupt IRD event is recorded at approximately 34 kya. Thus, our new IRD record is recording a series of additional episodic increases in IRD concentrations comparable in intensity to the identified Heinrich events. This suggests that ODP Site 980 sediments are recording a series of more closely spaced episodic increases in IRD concentration that can be directly related to the Dansgaard/Oeschger events recorded in Greenland ice cores. Comparison of our preliminary high resolution record of changes in the relative abundance of the polar species N. pachyderma, left coiling, to our IRD record suggests that the input of iceberg bearing waters precedes the increases in the relative abundance of N. pachyderma, left coiling for the early glacial IRD events. Whereas the abrupt increases in N. pachyderma, left coiling seem to occur during the later glacial IRD events. Thus, in the early glacial the influx of icebergs seem to occur before the invasion of cooler surface waters as opposed to the same time later in the glacial.

High time resolution characteristics of intermediate ion distributions upstream of the earth's bow shock

NASA Technical Reports Server (NTRS)

Potter, D. W.

1985-01-01

High time resolution particle data upstream of the bow shock during time intervals that have been identified as having intermediate ion distributions often show high amplitude oscillations in the ion fluxes of energy 2 and 6 keV. These ion oscillations, observed with the particle instruments of the University of California, Berkeley, on the ISEE 1 and 2 spacecraft, are at the same frequency (about 0.04 Hz) as the magnetic field oscillations. Typically, the 6-keV ion flux increases then the 2-keV flux increases followed by a decrease in the 2-keV flux and then the 6-keV flux decreases. This process repeats many times. Although there is no entirely satisfactory explanation, the presence of these ion flux oscillations suggests that distributions often are misidentified as intermediate ion distributions.

Inverse stochastic-dynamic models for high-resolution Greenland ice core records

NASA Astrophysics Data System (ADS)

Boers, Niklas; Chekroun, Mickael D.; Liu, Honghu; Kondrashov, Dmitri; Rousseau, Denis-Didier; Svensson, Anders; Bigler, Matthias; Ghil, Michael

2017-12-01

Proxy records from Greenland ice cores have been studied for several decades, yet many open questions remain regarding the climate variability encoded therein. Here, we use a Bayesian framework for inferring inverse, stochastic-dynamic models from δ18O and dust records of unprecedented, subdecadal temporal resolution. The records stem from the North Greenland Ice Core Project (NGRIP), and we focus on the time interval 59-22 ka b2k. Our model reproduces the dynamical characteristics of both the δ18O and dust proxy records, including the millennial-scale Dansgaard-Oeschger variability, as well as statistical properties such as probability density functions, waiting times and power spectra, with no need for any external forcing. The crucial ingredients for capturing these properties are (i) high-resolution training data, (ii) cubic drift terms, (iii) nonlinear coupling terms between the δ18O and dust time series, and (iv) non-Markovian contributions that represent short-term memory effects.

Hydraulic Tomography in Fractured Sedimentary Rocks to Estimate High-Resolution 3-D Distribution of Hydraulic Conductivity

NASA Astrophysics Data System (ADS)

Tiedeman, C. R.; Barrash, W.; Thrash, C. J.; Patterson, J.; Johnson, C. D.

2016-12-01

Hydraulic tomography was performed in a 100 m2 by 20 m thick volume of contaminated fractured mudstones at the former Naval Air Warfare Center (NAWC) in the Newark Basin, New Jersey, with the objective of estimating the detailed distribution of hydraulic conductivity (K). Characterizing the fine-scale K variability is important for designing effective remediation strategies in complex geologic settings such as fractured rock. In the tomography experiment, packers isolated two to six intervals in each of seven boreholes in the volume of investigation, and fiber-optic pressure transducers enabled collection of high-resolution drawdown observations. A hydraulic tomography dataset was obtained by conducting multiple aquifer tests in which a given isolated well interval was pumped and drawdown was monitored in all other intervals. The collective data from all tests display a wide range of behavior indicative of highly heterogeneous K within the tested volume, such as: drawdown curves for different intervals crossing one another on drawdown-time plots; unique drawdown curve shapes for certain intervals; and intervals with negligible drawdown adjacent to intervals with large drawdown. Tomographic inversion of data from 15 tests conducted in the first field season focused on estimating the K distribution at a scale of 1 m3 over approximately 25% of the investigated volume, where observation density was greatest. The estimated K field is consistent with prior geologic, geophysical, and hydraulic information, including: highly variable K within bedding-plane-parting fractures that are the primary flow and transport paths at NAWC, connected high-K features perpendicular to bedding, and a spatially heterogeneous distribution of low-K rock matrix and closed fractures. Subsequent tomographic testing was conducted in the second field season, with the region of high observation density expanded to cover a greater volume of the wellfield.

Physics of cardiac imaging with multiple-row detector CT.

PubMed

Mahesh, Mahadevappa; Cody, Dianna D

2007-01-01

Cardiac imaging with multiple-row detector computed tomography (CT) has become possible due to rapid advances in CT technologies. Images with high temporal and spatial resolution can be obtained with multiple-row detector CT scanners; however, the radiation dose associated with cardiac imaging is high. Understanding the physics of cardiac imaging with multiple-row detector CT scanners allows optimization of cardiac CT protocols in terms of image quality and radiation dose. Knowledge of the trade-offs between various scan parameters that affect image quality--such as temporal resolution, spatial resolution, and pitch--is the key to optimized cardiac CT protocols, which can minimize the radiation risks associated with these studies. Factors affecting temporal resolution include gantry rotation time, acquisition mode, and reconstruction method; factors affecting spatial resolution include detector size and reconstruction interval. Cardiac CT has the potential to become a reliable tool for noninvasive diagnosis and prevention of cardiac and coronary artery disease. (c) RSNA, 2007.

Fully integrated sub 100ps photon counting platform

NASA Astrophysics Data System (ADS)

Buckley, S. J.; Bellis, S. J.; Rosinger, P.; Jackson, J. C.

2007-02-01

Current state of the art high resolution counting modules, specifically designed for high timing resolution applications, are largely based on a computer card format. This has tended to result in a costly solution that is restricted to the computer it resides in. We describe a four channel timing module that interfaces to a computer via a USB port and operates with a resolution of less than 100 picoseconds. The core design of the system is an advanced field programmable gate array (FPGA) interfacing to a precision time interval measurement module, mass memory block and a high speed USB 2.0 serial data port. The FPGA design allows the module to operate in a number of modes allowing both continuous recording of photon events (time-tagging) and repetitive time binning. In time-tag mode the system reports, for each photon event, the high resolution time along with the chronological time (macro time) and the channel ID. The time-tags are uploaded in real time to a host computer via a high speed USB port allowing continuous storage to computer memory of up to 4 millions photons per second. In time-bin mode, binning is carried out with count rates up to 10 million photons per second. Each curve resides in a block of 128,000 time-bins each with a resolution programmable down to less than 100 picoseconds. Each bin has a limit of 65535 hits allowing autonomous curve recording until a bin reaches the maximum count or the system is commanded to halt. Due to the large memory storage, several curves/experiments can be stored in the system prior to uploading to the host computer for analysis. This makes this module ideal for integration into high timing resolution specific applications such as laser ranging and fluorescence lifetime imaging using techniques such as time correlated single photon counting (TCSPC).

Patient Navigation and Time to Diagnostic Resolution: Results for a Cluster Randomized Trial Evaluating the Efficacy of Patient Navigation among Patients with Breast Cancer Screening Abnormalities, Tampa, FL

PubMed Central

Lee, Ji-Hyun; Fulp, William; Wells, Kristen J.; Meade, Cathy D.; Calcano, Ercilia; Roetzheim, Richard

2013-01-01

Objectives The objective of this study was to evaluate a patient navigation (PN) program that attempts to reduce the time between a breast cancer screening abnormality and definitive diagnosis among medically underserved populations of Tampa Bay, Florida. Methods The Moffitt Patient Navigation Research Program conducted a cluster randomized design with 10 primary care clinics. Patients were navigated from time of a breast screening abnormality to diagnostic resolution. This paper examined the length of time between breast abnormality and definitive diagnosis, using a shared frailty Cox proportional hazard model to assess PN program effect. Results 1,039 patients were eligible for the study because of an abnormal breast cancer screening/clinical abnormality (494 navigated; 545 control). Analysis of PN effect by two time periods of resolution (0-3 months and > 3 months) showed a lagged effect of PN. For patients resolving in the first three months, the adjusted Hazard Ratio (aHR) was 0.85 (95% Confidence Interval [CI]: 0.64-1.13) suggesting that PN had no effect on resolution time during this period. Beyond three months, however, navigated patients resolved more quickly to diagnostic resolution compared with the control group (aHR 2.8, 95%CI: 1.30-6.13). The predicted aHR at 3 months was 1.2, which was not statistically significant, while PN had a significant positive effect beyond 4.7 months. Conclusions PN programs may increase the timeliness of diagnostic resolution for patients with a breast cancer-related abnormality. PN did not speed diagnostic resolution during the initial three months of follow up but started to reduce time to diagnostic resolution after three months and showed a significant effect after 4.7 months. Trial Registration ClinicalTrials.gov NCT00375024 PMID:24066145

High Resolution Time Series Observations of Bio-Optical and Physical Variability in the Arabian Sea

DTIC Science & Technology

1998-09-30

1995-October 20, 1995). Multi-variable moored systems ( MVMS ) were deployed by our group at 35 and 80m. The MVMS utilizes a VMCM to measure currents...similar to that of the UCSB MVMSs. WORK COMPLETED Our MVMS interdisciplinary systems with sampling intervals of a few minutes were placed on a mooring

Method and system for benchmarking computers

DOEpatents

Gustafson, John L.

1993-09-14

A testing system and method for benchmarking computer systems. The system includes a store containing a scalable set of tasks to be performed to produce a solution in ever-increasing degrees of resolution as a larger number of the tasks are performed. A timing and control module allots to each computer a fixed benchmarking interval in which to perform the stored tasks. Means are provided for determining, after completion of the benchmarking interval, the degree of progress through the scalable set of tasks and for producing a benchmarking rating relating to the degree of progress for each computer.

A 45 ps time digitizer with a two-phase clock and dual-edge two-stage interpolation in a field programmable gate array device

NASA Astrophysics Data System (ADS)

Szplet, R.; Kalisz, J.; Jachna, Z.

2009-02-01

We present a time digitizer having 45 ps resolution, integrated in a field programmable gate array (FPGA) device. The time interval measurement is based on the two-stage interpolation method. A dual-edge two-phase interpolator is driven by the on-chip synthesized 250 MHz clock with precise phase adjustment. An improved dual-edge double synchronizer was developed to control the main counter. The nonlinearity of the digitizer's transfer characteristic is identified and utilized by the dedicated hardware code processor for the on-the-fly correction of the output data. Application of presented ideas has resulted in the measurement uncertainty of the digitizer below 70 ps RMS over the time interval ranging from 0 to 1 s. The use of the two-stage interpolation and a fast FIFO memory has allowed us to obtain the maximum measurement rate of five million measurements per second.

Resolution of a Low-Lying Placenta and Placenta Previa Diagnosed at the Midtrimester Anatomy Scan.

PubMed

Durst, Jennifer K; Tuuli, Methodius G; Temming, Lorene A; Hamilton, Owen; Dicke, Jeffrey M

2018-02-05

To identify the incidence and resolution rates of a low-lying placenta or placenta previa and to assess the optimal time to perform follow-up ultrasonography (US) to assess for resolution. We conducted a retrospective cohort study of women with a diagnosis of a low-lying placenta or placenta previa at routine anatomic screening. Follow-up US examinations were reviewed to estimate the proportion of women who had resolution. A Kaplan-Meier survival curve was generated to estimate the median time to resolution. The distance of the placental edge from the internal cervical os was used to categorize the placenta as previa or low-lying (0.1-10 or ≥ 10-20 mm). A time-to-event analysis was used to estimate predictive factors and the time to resolution by distance from the os. A total of 1663 (8.7%) women had a diagnosis of a low-lying placenta or placenta previa. The cumulative resolution for women who completed 1 or more additional US examinations was 91.9% (95% confidence interval, 90.2%-93.3%). The median time to resolution was 10 (interquartile range [IQR], 7-13) weeks. The distance from the internal cervical os was known for 658 (51.0%) women. The probability of resolution was inversely proportional to the distance from the internal os: 99.5% (≥10-20 mm), 95.4% (0.1-10 mm), and 72.3% (placenta previa; P < .001). The median times to resolution were 9 (IQR, 7-12) weeks for 10 to 20 mm, 10 (IQR, 7-13) weeks for 0.1 to 10 mm, and 12 (IQR, 9-15) weeks for placenta previa (P = .0003, log rank test). A low-lying placenta or placenta previa diagnosed at the midtrimester anatomy survey resolves in most patients. Resolution is near universal in patients with an initial distance from the internal os of 10 mm or greater. © 2018 by the American Institute of Ultrasound in Medicine.

Upgrading and testing program for narrow band high resolution planetary IR imaging spectrometer

NASA Technical Reports Server (NTRS)

Wattson, R. B.; Rappaport, S.

1977-01-01

An imaging spectrometer, intended primarily for observations of the outer planets, which utilizes an acoustically tuned optical filter (ATOF) and a charge coupled device (CCD) television camera was modified to improve spatial resolution and sensitivity. The upgraded instrument was a spatial resolving power of approximately 1 arc second, as defined by an f/7 beam at the CCD position and it has this resolution over the 50 arc second field of view. Less vignetting occurs and sensitivity is four times greater. The spectral resolution of 15 A over the wavelength interval 6500 A - 11,000 A is unchanged. Mechanical utility has been increased by the use of a honeycomb optical table, mechanically rigid yet adjustable optical component mounts, and a camera focus translation stage. The upgraded instrument was used to observe Venus and Saturn.

Seasonal and high-resolution variability in hydrochemistry of the Andes-Amazon

NASA Astrophysics Data System (ADS)

Burt, E.; West, A. J.

2017-12-01

Stream hydrochemistry acts as a record of integrated catchment processes such as the amount of time it takes precipitation to flow through the subsurface and become streamflow (water transit times), water-rock interaction and biogeochemical cycling. Although it is understood that sampling interval affects observed patterns in hydrochemistry, most studies collect samples on a weekly, bi-weekly or monthly schedule due to lack of resources or the difficulty of maintaining automated sampling devices. Here, we attempt to combine information from two sampling time scales, comparing a year-long hydrochemical time series to data from a recent sub-daily sampling campaign. Starting in April 2016, river, soil and rain waters have been collected every two weeks at five small catchments spanning the tropical Andes and Amazon - a natural laboratory for its gradients in topography, erosion rates, precipitation, temperature and flora. Between January and March, 2017, we conducted high frequency sampling for approximately one week at each catchment, sampling at least every four hours including overnight. We will constrain young water fractions (Kirchner, 2016) and storm water fluxes for the experimental catchments using stable isotopes of water as conservative tracers. Major element data will provide the opportunity to make initial constraints on geochemical and hydrologic coupling. Preliminary results suggest that in the Amazon, hydrochemistry patterns are dependent on sampling frequency: the seasonal cycle in stable isotopes of water is highly damped, while the high resolution sampling displays large variability. This suggests that a two-week sampling interval is not frequent enough to capture rapid transport of water, perhaps through preferential flow networks. In the Andes, stable isotopes of water are highly damped in both the seasonal and high resolution cycle, suggesting that the catchment behaves as a "well-mixed" system.

Influence of air quality model resolution on uncertainty associated with health impacts

NASA Astrophysics Data System (ADS)

Thompson, T. M.; Selin, N. E.

2012-06-01

We use regional air quality modeling to evaluate the impact of model resolution on uncertainty associated with the human health benefits resulting from proposed air quality regulations. Using a regional photochemical model (CAMx), we ran a modeling episode with meteorological inputs representing conditions as they occurred during August through September 2006, and two emissions inventories (a 2006 base case and a 2018 proposed control scenario, both for Houston, Texas) at 36, 12, 4 and 2 km resolution. The base case model performance was evaluated for each resolution against daily maximum 8-h averaged ozone measured at monitoring stations. Results from each resolution were more similar to each other than they were to measured values. Population-weighted ozone concentrations were calculated for each resolution and applied to concentration response functions (with 95% confidence intervals) to estimate the health impacts of modeled ozone reduction from the base case to the control scenario. We found that estimated avoided mortalities were not significantly different between 2, 4 and 12 km resolution runs, but 36 km resolution may over-predict some potential health impacts. Given the cost/benefit analysis requirements of the Clean Air Act, the uncertainty associated with human health impacts and therefore the results reported in this study, we conclude that health impacts calculated from population weighted ozone concentrations obtained using regional photochemical models at 36 km resolution fall within the range of values obtained using fine (12 km or finer) resolution modeling. However, in some cases, 36 km resolution may not be fine enough to statistically replicate the results achieved using 2 and 4 km resolution. On average, when modeling at 36 km resolution, 7 deaths per ozone month were avoided because of ozone reductions resulting from the proposed emissions reductions (95% confidence interval was 2-9). When modeling at 2, 4 or 12 km finer scale resolution, on average 5 deaths were avoided due to the same reductions (95% confidence interval was 2-7). Initial results for this specific region show that modeling at a resolution finer than 12 km is unlikely to improve uncertainty in benefits analysis. We suggest that 12 km resolution may be appropriate for uncertainty analyses in areas with similar chemistry, but that resolution requirements should be assessed on a case-by-case basis and revised as confidence intervals for concentration-response functions are updated.

Clinical significance of the infection-free interval in the management of acute bacterial exacerbations of chronic bronchitis.

PubMed

Chodosh, Sanford

2005-06-01

Rational and appropriate antibiotic use for patients with acute exacerbation of chronic bronchitis (AECB) is a major concern, as approximately half of these patients do not have a bacterial infection. Typically, the result of antimicrobial therapy for patients with acute bacterial exacerbation of chronic bronchitis (ABECB) is not eradication of the pathogen but resolution of the acute symptoms. However, the length of time before the next bacterial exacerbation can be another important variable, as the frequency of exacerbations will affect the overall health of the patient and the rate of lung deterioration over time. Clinical trials comparing antimicrobial therapies commonly measure resolution of symptoms in AECB patients as the primary end point, regardless of whether the exacerbation is documented as bacterial in nature. Ideally, the scientific approach to assessing the efficacy of antibiotic therapy for ABECB should include a measurement of acute bacterial eradication rates in patients with documented bronchial bacterial infection followed by measurement of the infection-free interval (IFI), ie, the time to the next ABECB. The use of these variables can provide a standard for comparing various antimicrobial therapies. As we learn more about how antibiotics can affect the IFI, treatment decisions should be adapted to ensure optimal management of ABECB for the long-term.

ON ASYMMETRY OF MAGNETIC HELICITY IN EMERGING ACTIVE REGIONS: HIGH-RESOLUTION OBSERVATIONS

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

Tian Lirong; Alexander, David; Zhu Chunming

We employ the DAVE (differential affine velocity estimator) tracking technique on a time series of Michelson Doppler Imager (MDI)/1 minute high spatial resolution line-of-sight magnetograms to measure the photospheric flow velocity for three newly emerging bipolar active regions (ARs). We separately calculate the magnetic helicity injection rate of the leading and following polarities to confirm or refute the magnetic helicity asymmetry, found by Tian and Alexander using MDI/96 minute low spatial resolution magnetograms. Our results demonstrate that the magnetic helicity asymmetry is robust, being present in the three ARs studied, two of which have an observed balance of the magneticmore » flux. The magnetic helicity injection rate measured is found to depend little on the window size selected, but does depend on the time interval used between the two successive magnetograms being tracked. It is found that the measurement of the magnetic helicity injection rate performs well for a window size between 12 x 10 and 18 x 15 pixels and at a time interval {Delta}t = 10 minutes. Moreover, the short-lived magnetic structures, 10-60 minutes, are found to contribute 30%-50% of the magnetic helicity injection rate. Comparing with the results calculated by MDI/96 minute data, we find that the MDI/96 minute data, in general, can outline the main trend of the magnetic properties, but they significantly underestimate the magnetic flux in strong field regions and are not appropriate for quantitative tracking studies, so provide a poor estimate of the amount of magnetic helicity injected into the corona.« less

An ultra-high resolution last deglacial marine sediment records of the Northwest Atlantic Ocean

NASA Astrophysics Data System (ADS)

Rashid, H.; Piper, D.; Marche, B.; Vermooten, M.; Lazar, K.; Brockway, B.

2016-12-01

Lack of high sedimentation rate records of past changes pertaining to the late Pleistocene Laurentide ice-sheet (LIS) dynamics has prevented efforts to differentiate the various forcings in modulating abrupt climate changes. Here, we present an ultra-high resolution sediment record spanning approximately 1,500 km of the Eastern Canadian continental margin. The new record comprises four sediment cores which were collected from the northwest Labrador Sea (i.e., Saglek Bank) to southwestern Flemish Pass to the southeast Grand Banks in outer shelf and slope settings. Fifty new 14C-accelerator mass spectrometric dates were obtained to construct the stratigraphy. The total sediment thickness of the new record is 41 m covering the past 26 ka with 1.58/ka mean sediment rate, the highest sediment rate ever reported from the Northwest Atlantic Ocean for this time interval. Further, the temporal resolution of the record varies from a couple of decades to centuries depending on the time interval. X-ray fluorescence (XRF) data in conjunction with physical properties of sediments and petrology allowed us to distinguish sediment delivered by major ice-streams of the LIS namely the Hudson Strait, Hopedale Saddle, and Cumberland Sound ice streams. Heinrich layers 1 and 2 are well identified by their Labrador Sea specific characteristics. The so-called Younger Dryas equivalent Heinrich layer H0 was identified in these cores but the timing of onset of H0 has an offset by nearly 1,000 years with that of the 12.9 ka, suggesting that the YD event was not initiated by the Hudson Strait compared to other Heinrich events.

Ultrafast dynamic contrast-enhanced mri of the breast using compressed sensing: breast cancer diagnosis based on separate visualization of breast arteries and veins.

PubMed

Onishi, Natsuko; Kataoka, Masako; Kanao, Shotaro; Sagawa, Hajime; Iima, Mami; Nickel, Marcel Dominik; Toi, Masakazu; Togashi, Kaori

2018-01-01

To evaluate the feasibility of ultrafast dynamic contrast-enhanced (UF-DCE) magnetic resonance imaging (MRI) with compressed sensing (CS) for the separate identification of breast arteries/veins and perform temporal evaluations of breast arteries and veins with a focus on the association with ipsilateral cancers. Our Institutional Review Board approved this study with retrospective design. Twenty-five female patients who underwent UF-DCE MRI at 3T were included. UF-DCE MRI consisting of 20 continuous frames was acquired using a prototype 3D gradient-echo volumetric interpolated breath-hold sequence including a CS reconstruction: temporal resolution, 3.65 sec/frame; spatial resolution, 0.9 × 1.3 × 2.5 mm. Two readers analyzed 19 maximum intensity projection images reconstructed from subtracted images, separately identified breast arteries/veins and the earliest frame in which they were respectively visualized, and calculated the time interval between arterial and venous visualization (A-V interval) for each breast. In total, 49 breasts including 31 lesions (breast cancer, 16; benign lesion, 15) were identified. In 39 of the 49 breasts (breasts with cancers, 16; breasts with benign lesions, 10; breasts with no lesions, 13), both breast arteries and veins were separately identified. The A-V intervals for breasts with cancers were significantly shorter than those for breasts with benign lesions (P = 0.043) and no lesions (P = 0.007). UF-DCE MRI using CS enables the separate identification of breast arteries/veins. Temporal evaluations calculating the time interval between arterial and venous visualization might be helpful in the differentiation of ipsilateral breast cancers from benign lesions. 3 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;47:97-104. © 2017 International Society for Magnetic Resonance in Medicine.

Targeted Recombinant Progeny: a design for ultra-high resolution mapping of Quantitative Trait Loci in crosses between inbred or pure lines.

PubMed

Heifetz, Eliyahu M; Soller, Morris

2015-07-07

High-resolution mapping of the loci (QTN) responsible for genetic variation in quantitative traits is essential for positional cloning of candidate genes, and for effective marker assisted selection. The confidence interval (QTL) flanking the point estimate of QTN-location is proportional to the number of individuals in the mapping population carrying chromosomes recombinant in the given interval. Consequently, many designs for high resolution QTN mapping are based on increasing the proportion of recombinants in the mapping population. The "Targeted Recombinant Progeny" (TRP) design is a new design for high resolution mapping of a target QTN in crosses between pure, or inbred lines. It is a three-generation procedure generating a large number of recombinant individuals within a QTL previously shown to contain a QTN. This is achieved by having individuals that carry chromosomes recombinant across the target QTL interval as parents of a large mapping population; most of whom will therefore carry recombinant chromosomes targeted to the given QTL. The TRP design is particularly useful for high resolution mapping of QTN that differentiate inbred or pure lines, and hence are not amenable to high resolution mapping by genome-wide association tests. In the absence of residual polygenic variation, population sizes required for achieving given mapping resolution by the TRP-F2 design relative to a standard F2 design ranged from 0.289 for a QTN with standardized allele substitution effect = 0.2, mapped to an initial QTL of 0.2 Morgan to 0.041 for equivalent QTN mapped to an initial QTL of 0.02 M. In the presence of residual polygenic variation, the relative effectiveness of the TRP design ranges from 1.068 to 0.151 for the same initial QTL intervals and QTN effect. Thus even in the presence of polygenic variation, the TRP can still provide major savings. Simulation showed that mapping by TRP should be based on 30-50 markers spanning the initial interval; and on at least 50 or more G2 families representing this number of recombination points,. The TRP design can be an effective procedure for achieving high and ultra-high mapping resolution of a target QTN previously mapped to a known confidence interval (QTL).

[Non-contrast time-resolved magnetic resonance angiography combining high resolution multiple phase echo planar imaging based signal targeting and alternating radiofrequency contrast inherent inflow enhanced multi phase angiography combining spatial resolution echo planar imaging based signal targeting and alternating radiofrequency in intracranial arteries].

PubMed

Nakamura, Masanobu; Yoneyama, Masami; Tabuchi, Takashi; Takemura, Atsushi; Obara, Makoto; Sawano, Seishi

2012-01-01

Detailed information on anatomy and hemodynamics in cerebrovascular disorders such as AVM and Moyamoya disease is mandatory for defined diagnosis and treatment planning. Arterial spin labeling technique has come to be applied to magnetic resonance angiography (MRA) and perfusion imaging in recent years. However, those non-contrast techniques are mostly limited to single frame images. Recently we have proposed a non-contrast time-resolved MRA technique termed contrast inherent inflow enhanced multi phase angiography combining spatial resolution echo planar imaging based signal targeting and alternating radiofrequency (CINEMA-STAR). CINEMA-STAR can extract the blood flow in the major intracranial arteries at an interval of 70 ms and thus permits us to observe vascular construction in full by preparing MIP images of axial acquisitions with high spatial resolution. This preliminary study demonstrates the usefulness of the CINEMA-STAR technique in evaluating the cerebral vasculature.

Temporal structure in the light response of relay cells in the dorsal lateral geniculate nucleus of the cat.

PubMed Central

Funke, K; Wörgötter, F

1995-01-01

1. The spike interval pattern during the light responses of 155 on- and 81 off-centre cells of the dorsal lateral geniculate nucleus (LGN) was studied in anaesthetized and paralysed cats by the use of a novel analysis. Temporally localized interval distributions were computed from a 100 ms time window, which was shifted along the time axis in 10 ms steps, resulting in a 90% overlap between two adjacent windows. For each step the interval distribution was computed inside the time window with 1 ms resolution, and plotted as a greyscale-coded pixel line orthogonal to the time axis. For visual stimulation, light or dark spots of different size and contrast were presented with different background illumination levels. 2. Two characteristic interval patterns were observed during the sustained response component of the cells. Mainly on-cells (77%) responded with multimodal interval distributions, resulting in elongated 'bands' in the 2-dimensional time window plots. In similar situations, the interval distributions for most (71%) off-cells were rather wide and featureless. In those cases where interval bands (i.e. multimodal interval distributions) were observed for off-cells (14%), they were always much wider than for the on-cells. This difference between the on- and off-cell population was independent of the background illumination and the contrast of the stimulus. Y on-cells also tended to produce wider interval bands than X on-cells. 3. For most stimulation situations the first interval band was centred around 6-9 ms, which has been called the fundamental interval; higher order bands are multiples thereof. The fundamental interval shifted towards larger sizes with decreasing stimulus contrast. Increasing stimulus size, on the other hand, resulted in a redistribution of the intervals into higher order bands, while at the same time the location of the fundamental interval remained largely unaffected. This was interpreted as an effect of the increasing surround inhibition at the geniculate level, by which individual retinal EPSPs were cancelled. A changing level of adaptation can result in a mixed shift/redistribution effect because of the changing stimulus contrast and changing level of tonic inhibition. 4. The occurrence of interval bands is not directly related to the shape of the autocorrelation function, which can be flat, weakly oscillatory or strongly oscillatory, regardless of the interval band pattern. 5. A simple computer model was devised to account for the observed cell behaviour. The model is highly robust against parameter variations.(ABSTRACT TRUNCATED AT 400 WORDS) Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 15 PMID:7562612

Measurement of high-resolution mechanical contraction of cardiac muscle by induced eddy current.

PubMed

Lee, Young-Jae; Lee, Kang-Hwi; Kang, Seung-Jin; Kim, Kyeung-Nam; Khang, Seonah; Koo, Hye Ran; Gi, Sunok; Lee, Joo Hyeon; Lee, Jeong-Whan

2014-01-01

There are many types of devices which help to manage a personal health conditions such as heartbeat chest belt, pedometer and smart watch. And the most common device has the relationship with heart rate or ECG data. However, users have to attach some electrode or fasten the belt on the bare skin to measure bio-signal information. Therefore, most of people want more convenient and short-ready-time and no-need to attach electrode. In this paper, we proposed the high-resolution measuring system of mechanical activity of cardiac muscle and thereby measure heartbeat. The principle of the proposed measuring method is that the alternating current generate alternating magnetic field around coil. This primary magnetic field induces eddy current which makes magnetic field against primary coil in the nearby objects. To measure high-resolution changes of the induced secondary magnetic fields, we used digital Phase-locked loop(PLL) circuit which provides more high-resolution traces of frequency changes than the previous studies based on digital frequency counter method. As a result of our preliminary experiment, peak-peak intervals of the proposed method showed high correlation with R-R intervals of clinical ECG signals(r=0.9249). Also, from signal traces of the proposed method, we might make a conjecture that the contraction of atrium or ventricle is reflected by changing conductivity of cardiac muscle which is beating ceaselessly.

Relationship between large horizontal electric fields and auroral arc elements

NASA Astrophysics Data System (ADS)

Lanchester, B. S.; Kailá, K.; McCrea, I. W.

1996-03-01

High time resolution optical measurements in the magnetic zenith are compared with European Incoherent Scatter (EISCAT) field-aligned measurements of electron density at 0.2-s resolution and with horizontal electric field measurements made at 278 km with resolution of 9 s. In one event, 20 min after a spectacular auroral breakup, a system of narrow and active arc elements moved southward into the magnetic zenith, where it remained for several minutes. During a 30-s interval of activity in a narrow arc element very close to the radar beam, the electric field vectors at 3-s resolution were found to be extremely large (up to 400 mVm-1) and to point toward the bright optical features in the arc, which moved along its length. It is proposed that the large electric fields are short-lived and are directly associated with the particle precipitation that causes the bright features in auroral arc elements.

File Specification for the 7-km GEOS-5 Nature Run, Ganymed Release Non-Hydrostatic 7-km Global Mesoscale Simulation

NASA Technical Reports Server (NTRS)

da Silva, Arlindo M.; Putman, William; Nattala, J.

2014-01-01

This document describes the gridded output files produced by a two-year global, non-hydrostatic mesoscale simulation for the period 2005-2006 produced with the non-hydrostatic version of GEOS-5 Atmospheric Global Climate Model (AGCM). In addition to standard meteorological parameters (wind, temperature, moisture, surface pressure), this simulation includes 15 aerosol tracers (dust, sea-salt, sulfate, black and organic carbon), O3, CO and CO2. This model simulation is driven by prescribed sea-surface temperature and sea-ice, daily volcanic and biomass burning emissions, as well as high-resolution inventories of anthropogenic sources. A description of the GEOS-5 model configuration used for this simulation can be found in Putman et al. (2014). The simulation is performed at a horizontal resolution of 7 km using a cubed-sphere horizontal grid with 72 vertical levels, extending up to to 0.01 hPa (approximately 80 km). For user convenience, all data products are generated on two logically rectangular longitude-latitude grids: a full-resolution 0.0625 deg grid that approximately matches the native cubed-sphere resolution, and another 0.5 deg reduced-resolution grid. The majority of the full-resolution data products are instantaneous with some fields being time-averaged. The reduced-resolution datasets are mostly time-averaged, with some fields being instantaneous. Hourly data intervals are used for the reduced-resolution datasets, while 30-minute intervals are used for the full-resolution products. All full-resolution output is on the model's native 72-layer hybrid sigma-pressure vertical grid, while the reduced-resolution output is given on native vertical levels and on 48 pressure surfaces extending up to 0.02 hPa. Section 4 presents additional details on horizontal and vertical grids. Information of the model surface representation can be found in Appendix B. The GEOS-5 product is organized into file collections that are described in detail in Appendix C. Additional details about variables listed in this file specification can be found in a separate document, the GEOS-5 File Specification Variable Definition Glossary. Documentation about the current access methods for products described in this document can be found on the GEOS-5 Nature Run portal: http://gmao.gsfc.nasa.gov/projects/G5NR. Information on the scientific quality of this simulation will appear in a forthcoming NASA Technical Report Series on Global Modeling and Data Assimilation to be available from http://gmao.gsfc.nasa.gov/pubs/tm/.

Sedimentological and Stable Isotope Changes at the Messinian-Pliocene Boundary Along a West to East Mediterranean Transect.

NASA Astrophysics Data System (ADS)

Pierre, C.; Rouchy, J.; Blanc-Valleron, M.

2001-12-01

During Messinian times, the whole Mediterranean area was submitted to evaporitic conditions which ended by the "Lago-Mare" brackish episode before the reset of open marine conditions in the early Pliocene. These major paleoceanographic changes resulted from regional tectonic reorganizations and global climate changes at this critical time interval, both acting to modify drastically the physiography and the hydrological budget of the Mediterranean basins. There exist outcropping sections and a few deep-sea ODP cores which contain the complete and continuous sedimentary sequence of the Messinian-Pliocene boundary (MPB), making it possible to follow the paleoenvironmental changes at a high resolution scale. We compare here sedimentological and carbonate stable isotope records on three sections for which a high- resolution sampling was applied to the 2 meters thick interval including the MPB. In the Vera section from South Spain, there is no clear change in the carbonate content of the silty clay succession when crossing the MPB. The oxygen and carbon isotopic compositions of calcite both increase by 1 permil across a 40 cm-thick interval which corresponds to the Messinian-Pliocene transition. At ODP Site 968 from the eastern Levantine basin, there is an important sedimentary change between Messinian brown silty clays containing about 20 percent of carbonate and Pliocene gray nannofossil ooze which carbonate content averages 60 percent. Across this 10 cm-thick transitional interval, the oxygen and carbon isotopic compositions of bulk calcite both increase by 4.5 permil. In the Pissouri section from Cyprus, the uppermost Messinian reddish to brown marls with paleosoils are overlain by white Pliocene marls. The carbonate content increases from 20 percent to reach 60 percent across a 40 cm-thick transitional interval. Within this interval corresponding to the MPB, the oxygen and carbon isotopic compositions increase by 4 permil and 2 permil respectively. These results indicate that the MPB is recorded everywhere from W to E Mediterranean by significant and sharp increases in the oxygen and carbon isotopic compositions, which indicate that the early Pliocene marine flooding of the Mediterranean basins was a very abrupt event.

The astronomical rhythm of Late-Devonian climate change (Kowala section, Holy Cross Mountains, Poland)

NASA Astrophysics Data System (ADS)

De Vleeschouwer, David; Rakociński, Michał; Racki, Grzegorz; Bond, David P. G.; Sobień, Katarzyna; Claeys, Philippe

2013-03-01

Rhythmical alternations between limestone and shales or marls characterize the famous Kowala section, Holy Cross Mountains, Poland. Two intervals of this section were studied for evidence of orbital cyclostratigraphy. The oldest interval spans the Frasnian-Famennian boundary, deposited under one of the hottest greenhouse climates of the Phanerozoic. The youngest interval encompasses the Devonian-Carboniferous (D-C) boundary, a pivotal moment in Earth's climatic history that saw a transition from greenhouse to icehouse. For the Frasnian-Famennian sequence, lithological variations are consistent with 405-kyr and 100-kyr eccentricity forcing and a cyclostratigraphic floating time-scale is presented. The interpretation of observed lithological rhythms as eccentricity cycles is confirmed by amplitude modulation patterns in agreement with astronomical theory and by the recognition of precession cycles in high-resolution stable isotope records. The resulting relative time-scale suggests that ˜800 kyr separate the Lower and Upper Kellwasser Events (LKE and UKE, respectively), two periods of anoxia that culminated in massive biodiversity loss at the end of the Frasnian. Th/U and pyrite framboid analyses indicate that during the UKE, oxygen levels remained low for 400 kyr and δ13Corg measurements demonstrate that more than 600 kyr elapsed before the carbon cycle reached a steady state after a +3‰ UKE excursion. The Famennian-Tournaisian (D-C) interval also reveals eccentricity and precession-related lithological variations. Precession-related alternations clearly demonstrate grouping into 100-kyr bundles. The Famennian part of this interval is characterized by several distinctive anoxic black shales, including the Annulata, Dasberg and Hangenberg shales. Our high-resolution cyclostratigraphic framework indicates that those shales were deposited at 2.2 and 2.4 Myr intervals respectively. These durations strongly suggest a link between the long-period (˜2.4 Myr) eccentricity cycle and the development of the Annulata, Dasberg and Hangenberg anoxic shales. It is assumed that these black shales form under transgressive conditions, when extremely high eccentricity promoted the collapse of small continental ice-sheets at the most austral latitudes of western Gondwana.

Light-scattering analysis of ultrasonic wave's influence on the RBC agglutination in vitro

NASA Astrophysics Data System (ADS)

Doubrovski, Valeri A.; Dvoretski, Costanten N.

1999-04-01

Elastic light scattering is one of the most often used optical methods to analyze the cells agglutination reaction - the base of a great number of medical diagnostic test and biomedical investigations. The increase of the resolution of methods and apparatus towards the induced cells aggregation - the foundation of the reaction of agglutination, is quite an actual problem. The solution of this problem increases the reliability of the diagnostic test and gives an opportunity to achieve the diagnostic information in the cases when the traditional approaches do not lead to the diagnostic results. The attempt to increase the resolution of the immune reaction analyzer by means of ultrasonic waves action on the reagent mixture in vitro is taken in this paper. The RBC agglutination reaction which is usually used for the blood group type examination is chosen as an example of an object of the investigation. Different laser optical trains of the devices based on the turbidimetric and nephelometric methods and their combination are analyzed here. The influence of the ultrasonic wave time interval action and of the features of the sample preparation procedure on the resolution towards the agglutination process was investigated in this work. It is shown that the ultrasonic wave action on the reagent mixture leads to a large gain in the resolution of the device towards the RBC agglutination process. The experiments showed that the resolution of the device was enough to register the agglutination process even for the erythrocytes with weak agglutination ability when the reaction was invisible without ultrasonic action. It occurred that the diagnostic test time was more than by an order shortened due to the ultrasonic wave action. The optimal ultrasonic time interval action, the sample preparation technology and experimental technique were defined. The principle of the ultrasonic wave action on the cells agglutination process suggested here can be spread out on the immune molecular media. The results may be useful to develop new apparatus and methods for the aims of medical laboratory diagnostics.

Spontaneous Resolution of Genital Chlamydia trachomatis Infection in Women and Protection from Reinfection

PubMed Central

Geisler, William M.; Lensing, Shelly Y.; Press, Christen G.; Hook, Edward W.

2013-01-01

The natural history of chlamydia is variable and may include persisting asymptomatic infection, complications, or spontaneous resolution before treatment. Reinfection is common. We evaluated whether spontaneous resolution was associated with decreased reinfection in women returning for treatment of a positive chlamydia screening test. At enrollment, participants were tested for chlamydia, treated with azithromycin, and scheduled for a 6-month follow-up visit for repeat testing. Two hundred participants returned 1 to 12 months after treatment. Spontaneous resolution at enrollment was demonstrated in 44 (22.0%). Reinfection at follow-up occurred in 33 (16.5%), being more frequent in those with persisting infection at enrollment versus spontaneous resolution (31 of 156 [19.9%] vs 2 of 44 [4.5%]; P = .016). Adjusting for age, the odds of reinfection was 4 times higher for participants with persisting infection at enrollment (odds ratio 4.0, 95% confidence interval, 1.1–25.6; P = .034). Chlamydia treatment may attenuate protective immunity in some patients. PMID:23470847

Spontaneous resolution of genital Chlamydia trachomatis infection in women and protection from reinfection.

PubMed

Geisler, William M; Lensing, Shelly Y; Press, Christen G; Hook, Edward W

2013-06-15

The natural history of chlamydia is variable and may include persisting asymptomatic infection, complications, or spontaneous resolution before treatment. Reinfection is common. We evaluated whether spontaneous resolution was associated with decreased reinfection in women returning for treatment of a positive chlamydia screening test. At enrollment, participants were tested for chlamydia, treated with azithromycin, and scheduled for a 6-month follow-up visit for repeat testing. Two hundred participants returned 1 to 12 months after treatment. Spontaneous resolution at enrollment was demonstrated in 44 (22.0%). Reinfection at follow-up occurred in 33 (16.5%), being more frequent in those with persisting infection at enrollment versus spontaneous resolution (31 of 156 [19.9%] vs 2 of 44 [4.5%]; P = .016). Adjusting for age, the odds of reinfection was 4 times higher for participants with persisting infection at enrollment (odds ratio 4.0, 95% confidence interval, 1.1-25.6; P = .034). Chlamydia treatment may attenuate protective immunity in some patients.

Dynamic MRI for distinguishing high-flow from low-flow peripheral vascular malformations.

PubMed

Ohgiya, Yoshimitsu; Hashimoto, Toshi; Gokan, Takehiko; Watanabe, Shouji; Kuroda, Masayoshi; Hirose, Masanori; Matsui, Seishi; Nobusawa, Hiroshi; Kitanosono, Takashi; Munechika, Hirotsugu

2005-11-01

The purpose of our study was to assess the usefulness of dynamic MRI in distinguishing high-flow vascular malformations from low-flow vascular malformations, which do not need angiography for treatment. Between September 2001 and January 2003, 16 patients who underwent conventional and dynamic MRI had peripheral vascular malformations (six high- and 10 low-flow). The temporal resolution of dynamic MRI was 5 sec. Time intervals between beginning of enhancement of an arterial branch in the vicinity of a lesion in the same slice and the onset of enhancement in the lesion were calculated. We defined these time intervals as "artery-lesion enhancement time." Time intervals between the onset of enhancement in the lesion and the time of the maximal percentage of enhancement above baseline of the lesion within 120 sec were measured. We defined these time intervals as "contrast rise time" of the lesion. Diagnosis of the peripheral vascular malformations was based on angiographic or venographic findings. The mean artery-lesion enhancement time of the high-flow vascular malformations (3.3 sec [range, 0-5 sec]) was significantly shorter than that of the low-flow vascular malformations (8.8 sec [range, 0-20 sec]) (Mann-Whitney test, p < 0.05). The mean maximal lesion enhancement time of the high-flow vascular malformations (5.8 sec [range, 5-10 sec]) was significantly shorter than that of the low-flow vascular malformations (88.4 sec [range, 50-100 sec]) (Mann-Whitney test, p < 0.01). Dynamic MRI is useful for distinguishing high-flow from low-flow vascular malformations, especially when the contrast rise time of the lesion is measured.

Simulation of heat and mass transfer in turbulent channel flow using the spectral-element method: effect of spatial resolution

NASA Astrophysics Data System (ADS)

Ryzhenkov, V.; Ivashchenko, V.; Vinuesa, R.; Mullyadzhanov, R.

2016-10-01

We use the open-source code nek5000 to assess the accuracy of high-order spectral element large-eddy simulations (LES) of a turbulent channel flow depending on the spatial resolution compared to the direct numerical simulation (DNS). The Reynolds number Re = 6800 is considered based on the bulk velocity and half-width of the channel. The filtered governing equations are closed with the dynamic Smagorinsky model for subgrid stresses and heat flux. The results show very good agreement between LES and DNS for time-averaged velocity and temperature profiles and their fluctuations. Even the coarse LES grid which contains around 30 times less points than the DNS one provided predictions of the friction velocity within 2.0% accuracy interval.

Millisecond resolution electron fluxes from the Cluster satellites: Calibrated EDI ambient electron data

NASA Astrophysics Data System (ADS)

Förster, Matthias; Rashev, Mikhail; Haaland, Stein

2017-04-01

The Electron Drift Instrument (EDI) onboard Cluster can measure 500 eV and 1 keV electron fluxes with high time resolution during passive operation phases in its Ambient Electron (AE) mode. Data from this mode is available in the Cluster Science Archive since October 2004 with a cadence of 16 Hz in the normal mode or 128 Hz for burst mode telemetry intervals. The fluxes are recorded at pitch angles of 0, 90, and 180 degrees. This paper describes the calibration and validation of these measurements. The high resolution AE data allow precise temporal and spatial diagnostics of magnetospheric boundaries and will be used for case studies and statistical studies of low energy electron fluxes in the near-Earth space. We show examples of applications.

Participants' barriers to diagnostic resolution and factors associated with needing patient navigation.

PubMed

Krok-Schoen, Jessica L; Brewer, Brittany M; Young, Gregory S; Weier, Rory C; Tatum, Cathy M; DeGraffinreid, Cecilia R; Paskett, Electra D

2015-08-15

Patient navigation (PN) may improve cancer care by identifying and removing patient-reported barriers to care. In 2012, the American College of Surgeons Commission on Cancer (CoC) announced that health care facilities seeking CoC accreditation must have PN processes in place by January 1, 2015. Given these unfunded mandates, hospitals are looking for cost-effective ways to implement PN. This study examined demographic and psychosocial predictors of barriers to diagnostic resolution among individuals with a cancer screening abnormality enrolled in the Ohio Patient Navigation Research Project. Data were obtained from patients who received care at 1 of 9 Ohio Patient Navigation Research Project intervention clinics. Descriptive statistics and logistic regression models were used. There were 424 participants, and 151 (35.6%) reported a barrier to diagnostic resolution within 90 days of study consent. The most commonly reported barriers were misconceptions about a test or treatment (16.4%), difficulty in communicating with the provider (15.0%), and scheduling problems (11.5%). Univariate analyses indicated that race, education, employment, income, insurance, clinic type, friend support, and physical and psychological functioning were significantly associated with reporting a barrier to diagnostic resolution. Multivariate analyses found that comorbidities (odds ratio, 1.65; 95% confidence interval, 1.04-2.61) and higher intrusive thoughts and feelings (odds ratio, 1.25; 95% confidence interval, 1.10-1.41) were significantly associated with reporting a barrier to diagnostic resolution. The results suggest that demographic and psychosocial factors are associated with barriers to diagnostic resolution. To ensure compliance with the CoC mandate and provide timely care to all patients, CoC-accredited facilities can systematically identify the patients most likely to have barriers to care and assign them to PN. © 2015 American Cancer Society.

A Near-Annual Record of Hurricane Activity From the Little Bahama Bank Over the Last 700 Years

NASA Astrophysics Data System (ADS)

Winkler, T. S.; van Hengstum, P. J.; Donnelly, J. P.; Sullivan, R.; Albury, N. A.

2016-12-01

Long-term and high-resolution records of hurricane activity that extend past the short observational record (<150 years) can help inform the drivers of regional hurricane activity. Blueholes in the tropical North Atlantic often provide oxygen limited environments that promote excellent sediment preservation through time, recording coarse-grained hurricane overwash deposits. Here we further develop a previous hurricane reconstruction from Thatchpoint Bluehole on Abaco Island using additional >8m vibracores collected with a Rossfelder P-3. The previous core analyzed (TPBH-C1, Continental Shelf Research, 2014) was likely obtained from the cave-area of the bluehole, and previous radiocarbon-dated bivalves deeper in the core were likely impacted by an old-carbon effect, casting doubt on the veracity of the previous age-model at this site. Recent overwash beds from Hurricane Jeanne (2004) and Hurricane Floyd (1999) are present at all coretops, and additional radiocarbon dating that includes terrestrial organic matter fragments indicates a near-annual sedimentation rate in the bluehole (>1cm yr-1), with the record spanning the last 700 years. Since 1866 CE, 12 hurricanes with wind speeds exceeding Category 2 on the Saffir-Simpson Scale (wind speeds 154-177 km hr-1) have passed within a 50 km radius of TPBH, many of which can be associated with coarse-grained overwash deposits in the top 200 cm of TPBH-C3. It appears from this high-resolution record that 1500-1650 CE and 1750-1800 CE were active intervals for hurricanes near Abaco, which were previously identified in a lower-resolution (multi-decadal) hurricane reconstruction from Abaco (Blackwood Sinkhole). Additionally, these active intervals coincide with evidence of regional storminess from multiple reconstructions based on historical archives (e.g.: Archivo General de Indias, newspapers, ships' logbooks, meteorological journals), and the 1500-1650 CE active interval falls within a previously identified 1400-1675 CE active interval of intense hurricane strikes on the Northeastern United States. Once the age-model is finalized, further comparison of this record to other regional oceanographic and high-resolution hurricane reconstructions may provide further insight into the drivers of hurricane activity during the last millennium.

Effects of temporal averaging on short-term irradiance variability under mixed sky conditions

NASA Astrophysics Data System (ADS)

Lohmann, Gerald M.; Monahan, Adam H.

2018-05-01

Characterizations of short-term variability in solar radiation are required to successfully integrate large numbers of photovoltaic power systems into the electrical grid. Previous studies have used ground-based irradiance observations with a range of different temporal resolutions and a systematic analysis of the effects of temporal averaging on the representation of variability is lacking. Using high-resolution surface irradiance data with original temporal resolutions between 0.01 and 1 s from six different locations in the Northern Hemisphere, we characterize the changes in representation of temporal variability resulting from time averaging. In this analysis, we condition all data to states of mixed skies, which are the most potentially problematic in terms of local PV power volatility. Statistics of clear-sky index k* and its increments Δk*τ (i.e., normalized surface irradiance and changes therein over specified intervals of time) are considered separately. Our results indicate that a temporal averaging time scale of around 1 s marks a transition in representing single-point irradiance variability, such that longer averages result in substantial underestimates of variability. Higher-resolution data increase the complexity of data management and quality control without appreciably improving the representation of variability. The results do not show any substantial discrepancies between locations or seasons.

Short-term memory stores organized by information domain.

PubMed

Noyce, Abigail L; Cestero, Nishmar; Shinn-Cunningham, Barbara G; Somers, David C

2016-04-01

Vision and audition have complementary affinities, with vision excelling in spatial resolution and audition excelling in temporal resolution. Here, we investigated the relationships among the visual and auditory modalities and spatial and temporal short-term memory (STM) using change detection tasks. We created short sequences of visual or auditory items, such that each item within a sequence arose at a unique spatial location at a unique time. On each trial, two successive sequences were presented; subjects attended to either space (the sequence of locations) or time (the sequence of inter item intervals) and reported whether the patterns of locations or intervals were identical. Each subject completed blocks of unimodal trials (both sequences presented in the same modality) and crossmodal trials (Sequence 1 visual, Sequence 2 auditory, or vice versa) for both spatial and temporal tasks. We found a strong interaction between modality and task: Spatial performance was best on unimodal visual trials, whereas temporal performance was best on unimodal auditory trials. The order of modalities on crossmodal trials also mattered, suggesting that perceptual fidelity at encoding is critical to STM. Critically, no cost was attributable to crossmodal comparison: In both tasks, performance on crossmodal trials was as good as or better than on the weaker unimodal trials. STM representations of space and time can guide change detection in either the visual or the auditory modality, suggesting that the temporal or spatial organization of STM may supersede sensory-specific organization.

Sedimentology and carbon-isotope stratigraphy of the Late Cretaceous Chalk Group in the Höllviken-1 core (SW Sweden)

NASA Astrophysics Data System (ADS)

Bøttger, Dorthe; Thibault, Nicolas; Anderskouv, Kresten

2016-04-01

The Höllviken-1 borehole is situated on the Skåne peninsula (SW Sweden) which was part of the Danish Basin in the Late Cretaceous. 1415 meters have been cored among which ca. 1100 meters cover the complete Upper Cretaceous to lower Danian Chalk Group. Besides the publication of a synthetic log and detailed foraminifer biozonation, supplemented by a number of rare macrofossil findings and description of a number of foraminifer holotypes (Brötzen, 1944), very few studies of the core have actually been performed, since the mid 1940s. A new project has thus been undertaken aiming at improving the stratigraphy of the Chalk Group in the Höllviken-1 core. The data presented here comprise the description of the interval 837-489 m covering a large part of the Campanian and the lower Maastrichtian. Two intervals with the presence of sand are noted in the Campanian and two intervals showing possibly progradational sequences of arenaceous marls to sand are present in the Maastrichtian. The purpose of this new study is to revise the foraminifer biostratigraphy of Brötzen and complement it with high-resolution carbon-isotope stratigraphy in order to establish a new age-model for the core and better constrain the timing of siliciclastic input into the Danish Basin. In addition, high-resolution sedimentological data will be used as a preliminary test for cyclostratigraphy of the chalk-marl intervals.

Classification mapping and species identification of salt marshes based on a short-time interval NDVI time-series from HJ-1 optical imagery

NASA Astrophysics Data System (ADS)

Sun, Chao; Liu, Yongxue; Zhao, Saishuai; Zhou, Minxi; Yang, Yuhao; Li, Feixue

2016-03-01

Salt marshes are seen as the most dynamic and valuable ecosystems in coastal zones, and in these areas, it is crucial to obtain accurate remote sensing information on the spatial distributions of species over time. However, discriminating various types of salt marsh is rather difficult because of their strong spectral similarities. Previous salt marsh mapping studies have focused mainly on high spatial and spectral (i.e., hyperspectral) resolution images combined with auxiliary information; however, the results are often limited to small regions. With a high temporal and moderate spatial resolution, the Chinese HuanJing-1 (HJ-1) satellite optical imagery can be used not only to monitor phenological changes of salt marsh vegetation over short-time intervals, but also to obtain coverage of large areas. Here, we apply HJ-1 satellite imagery to the middle coast of Jiangsu in east China to monitor changes in saltmarsh vegetation cover. First, we constructed a monthly NDVI time-series to classify various types of salt marsh and then we tested the possibility of using compressed time-series continuously, to broaden the applicability of this particular approach. Our principal findings are as follows: (1) the overall accuracy of salt marsh mapping based on the monthly NDVI time-series was 90.3%, which was ∼16.0% higher than the single-phase classification strategy; (2) a compressed time-series, including NDVI from six key months (April, June-September, and November), demonstrated very little reduction (2.3%) in overall accuracy but led to obvious improvements in unstable regions; and (3) a simple rule for Spartina alterniflora identification was established using a scene solely from November, which may provide an effective way for regularly monitoring its distribution.

Solar Wind Turbulence and Intermittency at 0.72 AU - Statistical Approach

NASA Astrophysics Data System (ADS)

Teodorescu, E.; Echim, M.; Munteanu, C.; Zhang, T.; Barabash, S. V.; Budnik, E.; Fedorov, A.

2014-12-01

Through this analysis we characterize the turbulent magnetic fluctuations by Venus Express Magnetometer, VEX-MAG in the solar wind during the last solar cycle minimum at a distance of 0.72 AU from the Sun. We analyze data recorded between 2007 and 2009 with time resolutions of 1 Hz and 32 Hz. In correlation with plasma data from the ASPERA instrument, Analyser of Space Plasma and Energetic Atoms, we identify 550 time intervals, at 1 Hz resolution, when VEX is in the solar wind and which satisfy selection criteria defined based on the amount and the continuity of the data. We identify 118 time intervals that correspond to fast solar wind. We compute the power spectral densities (PSD) for Bx, By, Bz, B, B2, B|| and B^. We perform a statistical analysis of the spectral indices computed for each of the PSD's and evidence a dependence of the spectral index on the solar wind velocity and a slight difference in power content between parallel and perpendicular components of the magnetic field. We also estimate the scale invariance of fluctuations by computing the Probability Distribution Functions (PDFs) for Bx, By, Bz, B and B2 time series and discuss the implications for intermittent turbulence. Research supported by the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement no 313038/STORM, and a grant of the Romanian Ministry of National Education, CNCS - UEFISCDI, project number PN-II-ID-PCE-2012-4-0418.

A New Empirical Definition of Major Depressive Episode Recovery and Its Positive Impact on Future Course of Illness.

PubMed

Judd, Lewis L; Schettler, Pamela J; Rush, A John; Coryell, William H; Fiedorowicz, Jess G; Solomon, David A

2016-08-01

To provide the first head-to-head test of the predictive validity of 2 resolution levels included in the current consensus definition of major depressive episode (MDE) recovery and provide an empirically based, clinically useful definition of the end of an MDE. 322 participants entering the National Institute of Mental Health Collaborative Depression Study with MDE (diagnosed by Research Diagnostic Criteria) in 1978-1981, and followed thereafter for up to 31 years, were divided into those with 8 consecutive weeks of asymptomatic MDE recovery or residual subsyndromal depressive symptom (SSD) resolution of their index MDE. These 2 levels of recovery were defined based on weekly symptom status on all depressive conditions, assessed by Longitudinal Interval Follow-Up Evaluation (LIFE) interviews conducted every 6 months. Primary measures of validity of these 2 alternative definitions were first well interval duration and long-term depressive illness burden. Groups were also compared on clinical variables, antidepressant treatment, and psychosocial function. 61.2% of subjects recovered asymptomatically from their index MDE. By survival analysis, they remained free of a depressive episode relapse or recurrence 4.2 times longer than those with SSD resolution (median = 135 vs 32 weeks; χ² = 70.65; P < .0001). This was not attributable to a difference in intensity of antidepressant medication. Compared to asymptomatic recovery, SSD resolution was associated with significantly longer and more severe index MDEs, with more miscellaneous psychopathology as well as increased long-term psychosocial dysfunction and a greater depressive illness burden during the ensuing 10 or 20 years. Asymptomatic MDE resolution was a stronger predictor of time well than any of 18 other predictors, singly or combined. Eight consecutive weeks of asymptomatic recovery had 93% overlap with a 4-week definition and conferred little benefit over 4 weeks. Four consecutive weeks of asymptomatic recovery defines the end of an MDE and the beginning of a stable well state with improved psychosocial function. Residual symptom resolution is a continuation of an active state of the episode, not the end of an MDE. © Copyright 2016 Physicians Postgraduate Press, Inc.

Uncovering the effective interval of resolution parameter across multiple community optimization measures

NASA Astrophysics Data System (ADS)

Li, Hui-Jia; Cheng, Qing; Mao, He-Jin; Wang, Huanian; Chen, Junhua

2017-03-01

The study of community structure is a primary focus of network analysis, which has attracted a large amount of attention. In this paper, we focus on two famous functions, i.e., the Hamiltonian function H and the modularity density measure D, and intend to uncover the effective thresholds of their corresponding resolution parameter γ without resolution limit problem. Two widely used example networks are employed, including the ring network of lumps as well as the ad hoc network. In these two networks, we use discrete convex analysis to study the interval of resolution parameter of H and D that will not cause the misidentification. By comparison, we find that in both examples, for Hamiltonian function H, the larger the value of resolution parameter γ, the less resolution limit the network suffers; while for modularity density D, the less resolution limit the network suffers when we decrease the value of γ. Our framework is mathematically strict and efficient and can be applied in a lot of scientific fields.

Zero-crossing approach to high-resolution reconstruction in frequency-domain optical-coherence tomography.

PubMed

Krishnan, Sunder Ram; Seelamantula, Chandra Sekhar; Bouwens, Arno; Leutenegger, Marcel; Lasser, Theo

2012-10-01

We address the problem of high-resolution reconstruction in frequency-domain optical-coherence tomography (FDOCT). The traditional method employed uses the inverse discrete Fourier transform, which is limited in resolution due to the Heisenberg uncertainty principle. We propose a reconstruction technique based on zero-crossing (ZC) interval analysis. The motivation for our approach lies in the observation that, for a multilayered specimen, the backscattered signal may be expressed as a sum of sinusoids, and each sinusoid manifests as a peak in the FDOCT reconstruction. The successive ZC intervals of a sinusoid exhibit high consistency, with the intervals being inversely related to the frequency of the sinusoid. The statistics of the ZC intervals are used for detecting the frequencies present in the input signal. The noise robustness of the proposed technique is improved by using a cosine-modulated filter bank for separating the input into different frequency bands, and the ZC analysis is carried out on each band separately. The design of the filter bank requires the design of a prototype, which we accomplish using a Kaiser window approach. We show that the proposed method gives good results on synthesized and experimental data. The resolution is enhanced, and noise robustness is higher compared with the standard Fourier reconstruction.

Gigavision - A weatherproof, multibillion pixel resolution time-lapse camera system for recording and tracking phenology in every plant in a landscape

NASA Astrophysics Data System (ADS)

Brown, T.; Borevitz, J. O.; Zimmermann, C.

2010-12-01

We have a developed a camera system that can record hourly, gigapixel (multi-billion pixel) scale images of an ecosystem in a 360x90 degree panorama. The “Gigavision” camera system is solar-powered and can wirelessly stream data to a server. Quantitative data collection from multiyear timelapse gigapixel images is facilitated through an innovative web-based toolkit for recording time-series data on developmental stages (phenology) from any plant in the camera’s field of view. Gigapixel images enable time-series recording of entire landscapes with a resolution sufficient to record phenology from a majority of individuals in entire populations of plants. When coupled with next generation sequencing, quantitative population genomics can be performed in a landscape context linking ecology and evolution in situ and in real time. The Gigavision camera system achieves gigapixel image resolution by recording rows and columns of overlapping megapixel images. These images are stitched together into a single gigapixel resolution image using commercially available panorama software. Hardware consists of a 5-18 megapixel resolution DSLR or Network IP camera mounted on a pair of heavy-duty servo motors that provide pan-tilt capabilities. The servos and camera are controlled with a low-power Windows PC. Servo movement, power switching, and system status monitoring are enabled with Phidgets-brand sensor boards. System temperature, humidity, power usage, and battery voltage are all monitored at 5 minute intervals. All sensor data is uploaded via cellular or 802.11 wireless to an interactive online interface for easy remote monitoring of system status. Systems with direct internet connections upload the full sized images directly to our automated stitching server where they are stitched and available online for viewing within an hour of capture. Systems with cellular wireless upload an 80 megapixel “thumbnail” of each larger panorama and full-sized images are manually retrieved at bi-weekly intervals. Our longer-term goal is to make gigapixel time-lapse datasets available online in an interactive interface that layers plant-level phenology data with gigapixel resolution images, genomic sequence data from individual plants with weather and other abitotic sensor data. Co-visualization of all of these data types provides researchers with a powerful new tool for examining complex ecological interactions across scales from the individual to the ecosystem. We will present detailed phenostage data from more than 100 plants of multiple species from our Gigavision timelapse camera at our “Big Blowout East” field site in the Indiana Dunes State Park, IN. This camera has been recording three to four 700 million pixel images a day since February 28, 2010. The camera field of view covers an area of about 7 hectares resulting in an average image resolution of about 1 pixel per centimeter over the entire site. We will also discuss some of the many technological challenges with developing and maintaining these types of hardware systems, collecting quantitative data from gigapixel resolution time-lapse data and effectively managing terabyte-sized datasets of millions of images.

EIVAN - AN INTERACTIVE ORBITAL TRAJECTORY PLANNING TOOL

NASA Technical Reports Server (NTRS)

Brody, A. R.

1994-01-01

The Interactive Orbital Trajectory planning Tool, EIVAN, is a forward looking interactive orbit trajectory plotting tool for use with Proximity Operations (operations occurring within a one kilometer sphere of the space station) and other maneuvers. The result of vehicle burns on-orbit is very difficult to anticipate because of non-linearities in the equations of motion governing orbiting bodies. EIVAN was developed to plot resulting trajectories, to provide a better comprehension of orbital mechanics effects, and to help the user develop heuristics for onorbit mission planning. EIVAN comprises a worksheet and a chart from Microsoft Excel on a Macintosh computer. The orbital path for a user-specified time interval is plotted given operator burn inputs. Fuel use is also calculated. After the thrust parameters (magnitude, direction, and time) are input, EIVAN plots the resulting trajectory. Up to five burns may be inserted at any time in the mission. Twenty data points are plotted for each burn and the time interval can be varied to accommodate any desired time frame or degree of resolution. Since the number of data points for each burn is constant, the mission duration can be increased or decreased by increasing or decreasing the time interval. The EIVAN program runs with Microsoft's Excel for execution on a Macintosh running Macintosh OS. A working knowledge of Excel is helpful, but not imperative, for interacting with EIVAN. The program was developed in 1989.

Autogenic geomorphic processes determine the resolution and fidelity of terrestrial paleoclimate records.

PubMed

Foreman, Brady Z; Straub, Kyle M

2017-09-01

Terrestrial paleoclimate records rely on proxies hosted in alluvial strata whose beds are deposited by unsteady and nonlinear geomorphic processes. It is broadly assumed that this renders the resultant time series of terrestrial paleoclimatic variability noisy and incomplete. We evaluate this assumption using a model of oscillating climate and the precise topographic evolution of an experimental alluvial system. We find that geomorphic stochasticity can create aliasing in the time series and spurious climate signals, but these issues are eliminated when the period of climate oscillation is longer than a key time scale of internal dynamics in the geomorphic system. This emergent autogenic geomorphic behavior imparts regularity to deposition and represents a natural discretization interval of the continuous climate signal. We propose that this time scale in nature could be in excess of 10 4 years but would still allow assessments of the rates of climate change at resolutions finer than the existing age model techniques in isolation.

Autogenic geomorphic processes determine the resolution and fidelity of terrestrial paleoclimate records

PubMed Central

Foreman, Brady Z.; Straub, Kyle M.

2017-01-01

Terrestrial paleoclimate records rely on proxies hosted in alluvial strata whose beds are deposited by unsteady and nonlinear geomorphic processes. It is broadly assumed that this renders the resultant time series of terrestrial paleoclimatic variability noisy and incomplete. We evaluate this assumption using a model of oscillating climate and the precise topographic evolution of an experimental alluvial system. We find that geomorphic stochasticity can create aliasing in the time series and spurious climate signals, but these issues are eliminated when the period of climate oscillation is longer than a key time scale of internal dynamics in the geomorphic system. This emergent autogenic geomorphic behavior imparts regularity to deposition and represents a natural discretization interval of the continuous climate signal. We propose that this time scale in nature could be in excess of 104 years but would still allow assessments of the rates of climate change at resolutions finer than the existing age model techniques in isolation. PMID:28924607

Tourism climate and thermal comfort in Sun Moon Lake, Taiwan.

PubMed

Lin, Tzu-Ping; Matzarakis, Andreas

2008-03-01

Bioclimate conditions at Sun Moon Lake, one of Taiwan's most popular tourist destinations, are presented. Existing tourism-related climate is typically based on mean monthly conditions of air temperature and precipitation and excludes the thermal perception of tourists. This study presents a relatively more detailed analysis of tourism climate by using a modified thermal comfort range for both Taiwan and Western/Middle European conditions, presented by frequency analysis of 10-day intervals. Furthermore, an integrated approach (climate tourism information scheme) is applied to present the frequencies of each facet under particular criteria for each 10-day interval, generating a time-series of climate data with temporal resolution for tourists and tourism authorities.

Tourism climate and thermal comfort in Sun Moon Lake, Taiwan

NASA Astrophysics Data System (ADS)

Lin, Tzu-Ping; Matzarakis, Andreas

2008-03-01

Bioclimate conditions at Sun Moon Lake, one of Taiwan’s most popular tourist destinations, are presented. Existing tourism-related climate is typically based on mean monthly conditions of air temperature and precipitation and excludes the thermal perception of tourists. This study presents a relatively more detailed analysis of tourism climate by using a modified thermal comfort range for both Taiwan and Western/Middle European conditions, presented by frequency analysis of 10-day intervals. Furthermore, an integrated approach (climate tourism information scheme) is applied to present the frequencies of each facet under particular criteria for each 10-day interval, generating a time-series of climate data with temporal resolution for tourists and tourism authorities.

Brownian trail rectified

NASA Astrophysics Data System (ADS)

Hurd, Alan J.; Ho, Pauline

The experiments described here indicate when one of Nature's best fractals -- the Brownian trail -- becomes nonfractal. In most ambient fluids, the trail of a Brownian particle is self-similar over many decades of length. For example, the trail of a submicron particle suspended in an ordinary liquid, recorded at equal time intervals, exhibits apparently discontinuous changes in velocity from macroscopic lengths down to molecular lengths: the trail is a random walk with no velocity memory from one step to the next. In ideal Brownian motion, the kinks in the trail persist to infinitesimal time intervals, i.e., it is a curve without tangents. Even in real Brownian motion in a liquid, the time interval must be shortened to approximately 10(-8) s before the velocity appears continuous. In sufficiently rarefied environments, this time resolution at which a Brownian trail is rectified from a curve without tangents to a smoothly varying trajectory is greatly lengthened, making it possible to study the kinetic regime by dynamic light scattering. Our recent experiments with particles in a plasma have demonstrated this capability. In this regime, the particle velocity persists over a finite step length allowing an analogy to an ideal gas with Maxwell-Boltzmann velocities; the particle mass could be obtained from equipartition. The crossover from ballistic flight to hydrodynamic diffusion was also seen.

Influence of air quality model resolution on uncertainty associated with health impacts

NASA Astrophysics Data System (ADS)

Thompson, T. M.; Selin, N. E.

2012-10-01

We use regional air quality modeling to evaluate the impact of model resolution on uncertainty associated with the human health benefits resulting from proposed air quality regulations. Using a regional photochemical model (CAMx), we ran a modeling episode with meteorological inputs simulating conditions as they occurred during August through September 2006 (a period representative of conditions leading to high ozone), and two emissions inventories (a 2006 base case and a 2018 proposed control scenario, both for Houston, Texas) at 36, 12, 4 and 2 km resolution. The base case model performance was evaluated for each resolution against daily maximum 8-h averaged ozone measured at monitoring stations. Results from each resolution were more similar to each other than they were to measured values. Population-weighted ozone concentrations were calculated for each resolution and applied to concentration response functions (with 95% confidence intervals) to estimate the health impacts of modeled ozone reduction from the base case to the control scenario. We found that estimated avoided mortalities were not significantly different between the 2, 4 and 12 km resolution runs, but the 36 km resolution may over-predict some potential health impacts. Given the cost/benefit analysis requirements motivated by Executive Order 12866 as it applies to the Clean Air Act, the uncertainty associated with human health impacts and therefore the results reported in this study, we conclude that health impacts calculated from population weighted ozone concentrations obtained using regional photochemical models at 36 km resolution fall within the range of values obtained using fine (12 km or finer) resolution modeling. However, in some cases, 36 km resolution may not be fine enough to statistically replicate the results achieved using 2, 4 or 12 km resolution. On average, when modeling at 36 km resolution, an estimated 5 deaths per week during the May through September ozone season are avoided because of ozone reductions resulting from the proposed emissions reductions (95% confidence interval was 2-8). When modeling at 2, 4 or 12 km finer scale resolution, on average 4 deaths are avoided due to the same reductions (95% confidence interval was 1-7). Study results show that ozone modeling at a resolution finer than 12 km is unlikely to reduce uncertainty in benefits analysis for this specific region. We suggest that 12 km resolution may be appropriate for uncertainty analyses of health impacts due to ozone control scenarios, in areas with similar chemistry, meteorology and population density, but that resolution requirements should be assessed on a case-by-case basis and revised as confidence intervals for concentration-response functions are updated.

Temporal and spatial scaling impacts on extreme precipitation

NASA Astrophysics Data System (ADS)

Eggert, B.; Berg, P.; Haerter, J. O.; Jacob, D.; Moseley, C.

2015-01-01

Both in the current climate and in the light of climate change, understanding of the causes and risk of precipitation extremes is essential for protection of human life and adequate design of infrastructure. Precipitation extreme events depend qualitatively on the temporal and spatial scales at which they are measured, in part due to the distinct types of rain formation processes that dominate extremes at different scales. To capture these differences, we first filter large datasets of high-resolution radar measurements over Germany (5 min temporally and 1 km spatially) using synoptic cloud observations, to distinguish convective and stratiform rain events. In a second step, for each precipitation type, the observed data are aggregated over a sequence of time intervals and spatial areas. The resulting matrix allows a detailed investigation of the resolutions at which convective or stratiform events are expected to contribute most to the extremes. We analyze where the statistics of the two types differ and discuss at which resolutions transitions occur between dominance of either of the two precipitation types. We characterize the scales at which the convective or stratiform events will dominate the statistics. For both types, we further develop a mapping between pairs of spatially and temporally aggregated statistics. The resulting curve is relevant when deciding on data resolutions where statistical information in space and time is balanced. Our study may hence also serve as a practical guide for modelers, and for planning the space-time layout of measurement campaigns. We also describe a mapping between different pairs of resolutions, possibly relevant when working with mismatched model and observational resolutions, such as in statistical bias correction.

Satellite-based drought monitoring in Kenya in an operational setting

NASA Astrophysics Data System (ADS)

Klisch, A.; Atzberger, C.; Luminari, L.

2015-04-01

The University of Natural Resources and Life Sciences (BOKU) in Vienna (Austria) in cooperation with the National Drought Management Authority (NDMA) in Nairobi (Kenya) has setup an operational processing chain for mapping drought occurrence and strength for the territory of Kenya using the Moderate Resolution Imaging Spectroradiometer (MODIS) NDVI at 250 m ground resolution from 2000 onwards. The processing chain employs a modified Whittaker smoother providing consistent NDVI "Mondayimages" in near real-time (NRT) at a 7-daily updating interval. The approach constrains temporally extrapolated NDVI values based on reasonable temporal NDVI paths. Contrary to other competing approaches, the processing chain provides a modelled uncertainty range for each pixel and time step. The uncertainties are calculated by a hindcast analysis of the NRT products against an "optimum" filtering. To detect droughts, the vegetation condition index (VCI) is calculated at pixel level and is spatially aggregated to administrative units. Starting from weekly temporal resolution, the indicator is also aggregated for 1- and 3-monthly intervals considering available uncertainty information. Analysts at NDMA use the spatially/temporally aggregated VCI and basic image products for their monthly bulletins. Based on the provided bio-physical indicators as well as a number of socio-economic indicators, contingency funds are released by NDMA to sustain counties in drought conditions. The paper shows the successful application of the products within NDMA by providing a retrospective analysis applied to droughts in 2006, 2009 and 2011. Some comparisons with alternative products (e.g. FEWS NET, the Famine Early Warning Systems Network) highlight main differences.

Global Ionospheric Perturbations Monitored by the Worldwide GPS Network

NASA Technical Reports Server (NTRS)

Ho, C. M.; Mannucci, A. T.; Lindqwister, U. J.; Pi, X. Q.

1996-01-01

Based on the delays of these (Global Positioning System-GPS)signals, we have generated high resolution global ionospheric TEC (Total Electronic Changes) maps at 15-minute intervals. Using a differential method comparing storm time maps with quiet time maps, we find that the ionopshere during this time storm has increased significantly (the percentage change relative to quiet times is greater than 150 percent) ...These preliminary results (those mentioned above plus other in the paper)indicate that the differential maping method, which is based on GPS network measurements appears to be a useful tool for studying the global pattern and evolution process of the entire ionospheric perturbation.

3D surface flow kinematics derived from airborne UAVSAR interferometric synthetic aperture radar to constrain the physical mechanisms controlling landslide motion

NASA Astrophysics Data System (ADS)

Delbridge, B. G.; Burgmann, R.; Fielding, E. J.; Hensley, S.; Schulz, W. H.

2013-12-01

This project focuses on improving our understanding of the physical mechanisms controlling landslide motion by studying the landslide-wide kinematics of the Slumgullion landslide in southwestern Colorado using interferometric synthetic aperture radar (InSAR) and GPS. The NASA/JPL UAVSAR airborne repeat-pass SAR interferometry system imaged the Slumgullion landslide from 4 look directions on eight flights in 2011 and 2012. Combining the four look directions allows us to extract the full 3-D velocity field of the surface. Observing the full 3-dimensional flow field allows us to extract the full strain tensor (assuming free surface boundary conditions and incompressible flow) since we have both the spatial resolution to take spatial derivates and full deformation information. COSMO-SkyMed(CSK) high-resolution Spotlight data was also acquired during time intervals overlapping with the UAVSAR one-week pairs, with intervals as short as one day. These observations allow for the quantitative testing of the deformation magnitude and estimated formal errors in the UAVSAR derived deformation field. We also test the agreement of the deformation at 20 GPS monitoring sites concurrently acquired by the USGS. We also utilize the temporal resolution of real-time GPS acquired by the UC Berkeley Active Tectonics Group during a temporary deployment from July 22nd - August 2nd. By combining this data with the kinematic data we hope to elucidate the response of the landslide to environmental changes such as rainfall, snowmelt, and atmospheric pressure, and consequently the mechanisms controlling the dynamics of the landslide system. To constrain the longer temporal dynamics, interferograms made from pairs of CSK images acquired in 2010, 2011, 2012 and 2013 reveal the slide deformation on a longer timescale by allowing us to measure meters of motion and see the average rates over year long intervals using pixel offset tracking of the high-resolution SAR amplitude images. The results of this study will also allow us to test the agreement and commensurability of UAVSAR- derived deformation with real-time GPS observations and traditional satellite-based SAR interferometry from the COSMOSkyMed system. We will not only help mitigate the hazards associated with large landslides, but also provide information on the limitations of current geodetic imaging techniques. This unique opportunity to compare several concurrent geodetic observations of the same deformation will provide constraints and recommendations for the design and implementation of future geodetic systems for the monitoring of Earth surface processes.

A single frame: imaging live cells twenty-five years ago.

PubMed

Fink, Rachel

2011-07-01

In the mid-1980s live-cell imaging was changed by the introduction of video techniques, allowing new ways to collect and store data. The increased resolution obtained by manipulating video signals, the ability to use time-lapse videocassette recorders to study events that happen over long time intervals, and the introduction of fluorescent probes and sensitive video cameras opened research avenues previously unavailable. The author gives a personal account of this evolution, focusing on cell migration studies at the Marine Biological Laboratory 25 years ago. Copyright © 2011 Wiley-Liss, Inc.

Real-Time Very High-Resolution Regional 4D Assimilation in Supporting CRYSTAL-FACE Experiment

NASA Technical Reports Server (NTRS)

Wang, Donghai; Minnis, Patrick

2004-01-01

To better understand tropical cirrus cloud physical properties and formation processes with a view toward the successful modeling of the Earth's climate, the CRYSTAL-FACE (Cirrus Regional Study of Tropical Anvils and Cirrus Layers - Florida Area Cirrus Experiment) field experiment took place over southern Florida from 1 July to 29 July 2002. During the entire field campaign, a very high-resolution numerical weather prediction (NWP) and assimilation system was performed in support of the mission with supercomputing resources provided by NASA Center for Computational Sciences (NCCS). By using NOAA NCEP Eta forecast for boundary conditions and as a first guess for initial conditions assimilated with all available observations, two nested 15/3 km grids are employed over the CRYSTAL-FACE experiment area. The 15-km grid covers the southeast US domain, and is run two times daily for a 36-hour forecast starting at 0000 UTC and 1200 UTC. The nested 3-km grid covering only southern Florida is used for 9-hour and 18-hour forecasts starting at 1500 and 0600 UTC, respectively. The forecasting system provided more accurate and higher spatial and temporal resolution forecasts of 4-D atmospheric fields over the experiment area than available from standard weather forecast models. These forecasts were essential for flight planning during both the afternoon prior to a flight day and the morning of a flight day. The forecasts were used to help decide takeoff times and the most optimal flight areas for accomplishing the mission objectives. See more detailed products on the web site http://asd-www.larc.nasa.gov/mode/crystal. The model/assimilation output gridded data are archived on the NASA Center for Computational Sciences (NCCS) UniTree system in the HDF format at 30-min intervals for real-time forecasts or 5-min intervals for the post-mission case studies. Particularly, the data set includes the 3-D cloud fields (cloud liquid water, rain water, cloud ice, snow and graupe/hail).

Holocene climatic variations in the Western Cordillera of Colombia: A multiproxy high-resolution record unravels the dual influence of ENSO and ITCZ

NASA Astrophysics Data System (ADS)

Muñoz, Paula; Gorin, Georges; Parra, Norberto; Velásquez, Cesar; Lemus, Diego; Monsalve-M., Carlos; Jojoa, Marcela

2017-01-01

The Páramo de Frontino (3460 m elevation) in Colombia is located approximately halfway between the Pacific and Atlantic oceans. It contains a 17 kyr long, stratigraphically continuous sedimentary sequence dated by 30 AMS 14C ages. Our study covers the last 11,500 cal yr and focuses on the biotic (pollen) and abiotic (microfluorescence-X or μXRF) components of this high mountain ecosystem. The pollen record provides a proxy for temperature and humidity with a resolution of 20-35 yr, and μXRF of Ti and Fe is a proxy for rainfall with a sub-annual (ca. 6-month) resolution. Temperature and humidity display rapid and significant changes over the Holocene. The rapid transition from a cold (mean annual temperature (MAT) 3.5 °C lower than today) and wet Younger Dryas to a warm and dry early Holocene is dated at 11,410 cal yr BP. During the Holocene, MAT varied from ca. 2.5 °C below to 3.5° above present-day temperature. Warm periods (11,410-10,700, 9700-6900, 4000-2400 cal yr BP) were separated by colder intervals. The last 2.4 kyr of the record is affected by human impact. The Holocene remained dry until 7500 cal yr BP. Then, precipitations increased to reach a maximum between 5000 and 4500 cal yr BP. A rapid decrease occurred until 3500 cal yr BP and the late Holocene was dry. Spectral analysis of μXRF data show rainfall cyclicity at millennial scale throughout the Holocene, and at centennial down to ENSO scale in more specific time intervals. The highest rainfall intervals correlate with the highest activity of ENSO. Variability in solar output is possibly the main cause for this millennial to decadal cyclicity. We interpret ENSO and ITCZ as the main climate change-driving mechanisms in Frontino. Comparison with high-resolution XRF data from the Caribbean Cariaco Basin (a proxy for rainfall in the coastal Venezuelian cordilleras) demonstrates that climate in Frontino was Pacific-driven (ENSO-dominated) during the YD and early Holocene, whereas it was Atlantic-driven in Cariaco (ITCZ-dominated). From ca. 8000 cal yr BP, climate in both areas was under the dual influence of ENSO and ITCZ, thereby showing existing teleconnections between the tropical Pacific and Atlantic oceans. The Frontino record is to date the highest-resolution Holocene study in NW Colombia. An implication of these results is that new records should be analyzed with multiproxy tools, in particular those providing high resolution time series, such as μXRF.

Map based navigation for autonomous underwater vehicles

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

Tuohy, S.T.; Leonard, J.J.; Bellingham, J.G.

1995-12-31

In this work, a map based navigation algorithm is developed wherein measured geophysical properties are matched to a priori maps. The objectives is a complete algorithm applicable to a small, power-limited AUV which performs in real time to a required resolution with bounded position error. Interval B-Splines are introduced for the non-linear representation of two-dimensional geophysical parameters that have measurement uncertainty. Fine-scale position determination involves the solution of a system of nonlinear polynomial equations with interval coefficients. This system represents the complete set of possible vehicle locations and is formulated as the intersection of contours established on each map frommore » the simultaneous measurement of associated geophysical parameters. A standard filter mechanisms, based on a bounded interval error model, predicts the position of the vehicle and, therefore, screens extraneous solutions. When multiple solutions are found, a tracking mechanisms is applied until a unique vehicle location is determined.« less

Learning to tell Neoproterozoic time

NASA Technical Reports Server (NTRS)

Knoll, A. H.

2000-01-01

In 1989, the International Commission on Stratigraphy established a Working Group on the Terminal Proterozoic Period. Nine years of intensive, multidisciplinary research by scientists from some two dozen countries have markedly improved the framework for the correlation and calibration of latest Proterozoic events. Three principal phenomena--the Marinoan ice age, Ediacaran animal diversification, and the beginning of the Cambrian Period--specify the limits and character of this interval, but chemostratigraphy and biostratigraphy based on single-celled microfossils (acritarchs), integrated with high-resolution radiometric dates, provide the temporal framework necessary to order and evaluate terminal Proterozoic tectonic, biogeochemical, climatic, and biological events. These data also provide a rational basis for choosing the Global Stratotype Section and Point (GSSP) that will define the beginning of this period. A comparable level of stratigraphic resolution may be achievable for the preceding Cryogenian Period, providing an opportunity to define this interval, as well, in chronostratigraphic terms--perhaps bounded at beginning and end by the onset of Sturtian glaciation and the decay of Marinoan ice sheets, respectively. Limited paleontological, isotopic, and radiometric data additionally suggest a real but more distant prospect of lower Neoproterozoic correlation and stratigraphic subdivision.

Monitoring the dynamics of surface water fraction from MODIS time series in a Mediterranean environment

NASA Astrophysics Data System (ADS)

Li, Linlin; Vrieling, Anton; Skidmore, Andrew; Wang, Tiejun; Turak, Eren

2018-04-01

Detailed spatial information of changes in surface water extent is needed for water management and biodiversity conservation, particularly in drier parts of the globe where small, temporally-variant wetlands prevail. Although global surface water histories are now generated from 30 m Landsat data, for many locations they contain large temporal gaps particularly for longer periods (>10 years) due to revisit intervals and cloud cover. Daily Moderate Resolution Imaging Spectrometer (MODIS) imagery has potential to fill such gaps, but its relatively coarse spatial resolution may not detect small water bodies, which can be of great ecological importance. To address this problem, this study proposes and tests options for estimating the surface water fraction from MODIS 16-day 500 m Bidirectional Reflectance Distribution Function (BRDF) corrected surface reflectance image composites. The spatial extent of two Landsat tiles over Spain were selected as test areas. We obtained a 500 m reference dataset on surface water fraction by spatially aggregating 30 m binary water masks obtained from the Landsat-derived C-version of Function of Mask (CFmask), which themselves were evaluated against high-resolution Google Earth imagery. Twelve regression tree models were developed with two approaches, Random Forest and Cubist, using spectral metrics derived from MODIS data and topographic parameters generated from a 30 m spatial resolution digital elevation model. Results showed that accuracies were higher when we included annual summary statistics of the spectral metrics as predictor variables. Models trained on a single Landsat tile were ineffective in mapping surface water in the other tile, but global models trained with environmental conditions from both tiles can provide accurate results for both study areas. We achieved the highest accuracy with Cubist global model (R2 = 0.91, RMSE = 11.05%, MAE = 7.67%). Our method was not only effective for mapping permanent water fraction, but also in accurately capturing temporal fluctuations of surface water. Based on this good performance, we produced surface water fraction maps at 16-day interval for the 2000-2015 MODIS archive. Our approach is promising for monitoring surface water fraction at high frequency time intervals over much larger regions provided that training data are collected across the spatial domain for which the model will be applied.

Orbitally resolved records of Oligocene ice-sheet dynamics and deep-water chemistry from ODP Site 689 (Maud Rise, Weddell Sea)

NASA Astrophysics Data System (ADS)

Bohaty, Steven M.; Huck, Claire E.; Liebrand, Diederik; Röhl, Ursula; Wilson, Paul; van de Flierdt, Tina; Pälike, Heiko

2016-04-01

The early stages of the modern 'Icehouse' climate state first developed in the Oligocene following rapid global cooling and the onset of Antarctic glaciation at the Eocene-Oligocene Transition (34 Ma). However, the size and stability of the early Antarctic ice sheets that existed during the Oligocene under atmospheric CO2 levels higher than present day are poorly known. Here we report on an ongoing investigation of Oligocene (hemi)pelagic drillcores recovered at Ocean Drilling Program (ODP) Site 689, drilled on Maud Rise in the eastern Weddell Sea in late 1980s (Leg 113). Shipboard physical properties data were not routinely collected from pre-Quaternary cores at this site, and the lack of continuous composite sections and supporting data has previously been a considerable hindrance to high-resolution paleoceanographic studies. New high-resolution XRF scanning, discrete magnetic susceptibility, and benthic foraminiferal stable isotope records were collected from the upper Eocene-upper Oligocene interval of ODP Sites 689. The XRF datasets allow compositing of Holes 689B and 689D, which fortuitously contain offset cores throughout the sequence. Although condensed in two intervals, Site 689 contains a complete ~12-Myr record spanning Chron C17n.1n to Chron C8n.1n (~37 to 25 Ma). The composited records from Sites 689 exhibit prominent orbital-scale cyclicity in XRF-derived iron/calcium ratios, enabling development of an astronomical age model and detailed reconstruction of carbonate dissolution intensity of South Atlantic deep waters. These composited and well-dated records from Site 689 will, for the first-time, provide an Oligocene pelagic reference section for the Southern Ocean and serve as stratigraphic stepping stone between proximal Antarctic shelf records and high-resolution proxy records from lower latitude locations. Further development of high-resolution benthic foraminiferal and detrital neodymium isotope records at Site 689 will address the timing and frequency of East Antarctic ice-sheet advance and retreat events during cool intervals of the mid Oligocene and the onset of warming in the latest Oligocene. These data will both inform and test model results of ice-sheet behaviour and stability during different climatic phases of the Oligocene.

High-resolution analysis of upper Miocene lake deposits: Evidence for the influence of Gleissberg-band solar forcing

PubMed Central

Kern, Andrea K.; Harzhauser, Mathias; Soliman, Ali; Piller, Werner E.; Mandic, Oleg

2013-01-01

A high-resolution multi-proxy analysis was conducted on a 1.5-m-long core of Tortonian age (~ 10.5 Ma; Late Miocene) from Austria (Europe). The lake sediments were studied with a 1-cm resolution to detect all small-scale variations based on palynomorphs (pollen and dinoflagellate cysts), ostracod abundance, geochemistry (carbon and sulfur) and geophysics (magnetic susceptibility and natural gamma radiation). Based on an already established age model for a longer interval of the same core, this sequence can be limited to approx. two millennia of Late Miocene time with a resolution of ~ 13.7 years per sample. The previous study documented the presence of solar forcing, which was verified within various proxies on this 1.5-m core by a combination of REDFIT spectra and Gaussian filters. Significant repetitive signals ranged in two discrete intervals corresponding roughly to 55–82 and 110–123 years, fitting well within the lower and upper Gleissberg cycle ranges. Based on these results, the environmental changes along the 2000-year Late Miocene sequence are discussed. No major ecological turnovers are expected in this very short interval. Nonetheless, even within this brief time span, dinoflagellates document rapid changes between oligotrophic and eutrophic conditions, which are frequently coupled with lake stratification and dysoxic bottom waters. These phases prevented ostracods and molluscs from settling and promoted the activity of sulfur bacteria. The pollen record indicates rather stable wetland vegetation with a forested hinterland. Shifts in the pollen spectra can be mainly attributed to variations in transport mechanisms. These are represented by a few phases of fluvial input but mainly by changes in wind intensity and probably also wind direction. Such influence is most likely caused by solar cycles, leading to a change in source area for the input into the lake. Furthermore, these solar-induced variations seem to be modulated by longer solar cycles. The filtered data display comparable patterns and modulations, which seem to be forced by the 1000-year and 1500-year cycles. The 1000-year cycle modulated especially the lake surface proxies, whereas the 1500-year cycle is mainly reflected in hinterland proxies, indicating strong influence on transport mechanisms. PMID:23407808

Enhancing quantum sensing sensitivity by a quantum memory

PubMed Central

Zaiser, Sebastian; Rendler, Torsten; Jakobi, Ingmar; Wolf, Thomas; Lee, Sang-Yun; Wagner, Samuel; Bergholm, Ville; Schulte-Herbrüggen, Thomas; Neumann, Philipp; Wrachtrup, Jörg

2016-01-01

In quantum sensing, precision is typically limited by the maximum time interval over which phase can be accumulated. Memories have been used to enhance this time interval beyond the coherence lifetime and thus gain precision. Here, we demonstrate that by using a quantum memory an increased sensitivity can also be achieved. To this end, we use entanglement in a hybrid spin system comprising a sensing and a memory qubit associated with a single nitrogen-vacancy centre in diamond. With the memory we retain the full quantum state even after coherence decay of the sensor, which enables coherent interaction with distinct weakly coupled nuclear spin qubits. We benchmark the performance of our hybrid quantum system against use of the sensing qubit alone by gradually increasing the entanglement of sensor and memory. We further apply this quantum sensor-memory pair for high-resolution NMR spectroscopy of single 13C nuclear spins. PMID:27506596

Steepening of Waves at the Duskside Magnetopause

NASA Technical Reports Server (NTRS)

Plaschke, F.; Kahr, N.; Fischer, D.; Nakamura, R.; Baumjohann, W.; Magnes, W.; Burch, J. L.; Torbert, R.; Russell, C. T.; Giles, B. L.;

Characterization of Large-Area SiPM Array for PET Applications

NASA Astrophysics Data System (ADS)

Du, Junwei; Yang, Yongfeng; Bai, Xiaowei; Judenhofer, Martin S.; Berg, Eric; Di, Kun; Buckley, Steve; Jackson, Carl; Cherry, Simon R.

2016-02-01

The performance of an 8 ×8 array of 6.0 ×6.0 mm2 (active area) SiPMs was evaluated for PET applications using crystal arrays with different pitch sizes (3.4, 1.5, 1.35, and 1.2 mm) and custom designed five-channel front-end readout electronics (four channels for position information and one channel for timing information). The total area of this SiPM array is 57.4 ×57.4 mm2, and the pitch size is 7.2 mm. It was fabricated using enhanced blue sensitivity SiPMs (MicroFB-60035-SMT) with peak spectral sensitivity at 420 nm. The performance of the SiPM array was characterized by measuring flood histogram decoding quality, energy resolution, timing resolution and saturation at several bias voltages (from 25.0 to 30.0 V in 0.5 V intervals) and two different temperatures ( 5° C and 20°C). Results show that the best flood histogram was obtained at a bias voltage of 28.0 V and 5°C and an array of polished LSO crystals with a pitch as small as 1.2 mm can be resolved. No saturation was observed up to a bias voltage of 29.5 V during the experiments, due to adequate light sharing between SiPMs. Energy resolution and timing resolution at 5°C ranged from 12.7 ±0.8% to 14.6 ±1.4% and 1.58 ±0.13 ns to 2.50 ±0.44 ns, for crystal array pitch sizes of 3.4 and 1.2 mm, respectively. Superior flood histogram quality, energy resolution and timing resolution were obtained with larger crystal array pitch sizes and at lower temperature. Based on our findings, we conclude that this large-area SiPM array can serve as a suitable photodetector for high-resolution small-animal PET or dedicated human brain PET scanners.

Costs and outcomes evaluation of patient navigation after abnormal cancer screening: evidence from the Patient Navigation Research Program.

PubMed

Bensink, Mark E; Ramsey, Scott D; Battaglia, Tracy; Fiscella, Kevin; Hurd, Thelma C; McKoy, June M; Patierno, Steven R; Raich, Peter C; Seiber, Eric E; Warren-Mears, Victoria; Whitley, Elizabeth; Paskett, Electra D; Mandelblatt, S

2014-02-15

Navigators can facilitate timely access to cancer services, but to the authors' knowledge there are little data available regarding their economic impact. The authors conducted a cost-consequence analysis of navigation versus usual care among 10,521 individuals with abnormal breast, cervical, colorectal, or prostate cancer screening results who enrolled in the Patient Navigation Research Program study from January 1, 2006 to March 31, 2010. Navigation costs included diagnostic evaluation, patient and staff time, materials, and overhead. Consequences or outcomes were time to diagnostic resolution and probability of resolution. Differences in costs and outcomes were evaluated using multilevel, mixed-effects regression modeling adjusting for age, race/ethnicity, language, marital status, insurance status, cancer, and site clustering. The majority of individuals were members of a minority (70.7%) and uninsured or publically insured (72.7%). Diagnostic resolution was higher for navigation versus usual care at 180 days (56.2% vs 53.8%; P = .008) and 270 days (70.0% vs 68.2%; P < .001). Although there were no differences in the average number of days to resolution between the 2 groups (110 days vs 109 days; P = .63), the probability of ever having diagnostic resolution was higher for the navigation group versus the usual-care group (84.5% vs 79.6%; P < .001). The added cost of navigation versus usual care was $275 per patient (95% confidence interval, $260-$290; P < .001). There was no significant difference in stage distribution among the 12.4% of patients in the navigation group vs 11% of the usual-care patients diagnosed with cancer. Navigation adds costs and modestly increases the probability of diagnostic resolution among patients with abnormal screening test results. Navigation is only likely to be cost-effective if improved resolution translates into an earlier cancer stage at the time of diagnosis. © 2013 American Cancer Society.

Treatment of temporal aliasing effects in the context of next generation satellite gravimetry missions

NASA Astrophysics Data System (ADS)

Daras, Ilias; Pail, Roland

2017-09-01

Temporal aliasing effects have a large impact on the gravity field accuracy of current gravimetry missions and are also expected to dominate the error budget of Next Generation Gravimetry Missions (NGGMs). This paper focuses on aspects concerning their treatment in the context of Low-Low Satellite-to-Satellite Tracking NGGMs. Closed-loop full-scale simulations are performed for a two-pair Bender-type Satellite Formation Flight (SFF), by taking into account error models of new generation instrument technology. The enhanced spatial sampling and error isotropy enable a further reduction of temporal aliasing errors from the processing perspective. A parameterization technique is adopted where the functional model is augmented by low-resolution gravity field solutions coestimated at short time intervals, while the remaining higher-resolution gravity field solution is estimated at a longer time interval. Fine-tuning the parameterization choices leads to significant reduction of the temporal aliasing effects. The investigations reveal that the parameterization technique in case of a Bender-type SFF can successfully mitigate aliasing effects caused by undersampling of high-frequency atmospheric and oceanic signals, since their most significant variations can be captured by daily coestimated solutions. This amounts to a "self-dealiasing" method that differs significantly from the classical dealiasing approach used nowadays for Gravity Recovery and Climate Experiment processing, enabling NGGMs to retrieve the complete spectrum of Earth's nontidal geophysical processes, including, for the first time, high-frequency atmospheric and oceanic variations.

CERES Monthly Gridded Single Satellite Fluxes and Clouds (FSW) in HDF (CER_FSW_TRMM-PFM-VIRS_Beta1)

NASA Technical Reports Server (NTRS)

Wielicki, Bruce A. (Principal Investigator); Barkstrom, Bruce R. (Principal Investigator)

The Monthly Gridded Radiative Fluxes and Clouds (FSW) product contains a month of space and time averaged Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The FSW is also produced for combinations of scanner instruments. All instantaneous fluxes from the CERES CRS product for a month are sorted by 1-degree spatial regions and by the Universal Time (UT) hour of observation. The mean of the instantaneous fluxes for a given region-hour bin is determined and recorded on the FSW along with other flux statistics and scene information. The mean adjusted fluxes at the four atmospheric levels defined by CRS are also included for both clear-sky and total-sky scenes. In addition, four cloud height categories are defined by dividing the atmosphere into four intervals with boundaries at the surface, 700-, 500-, 300-hPa, and the Top-of-the-Atmosphere (TOA). The cloud layers from CRS are put into one of the cloud height categories and averaged over the region. The cloud properties are also column averaged and included on the FSW. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-01-01; Stop_Date=2000-03-31] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Latitude_Resolution=1 degree; Longitude_Resolution=1 degree; Horizontal_Resolution_Range=100 km - < 250 km or approximately 1 degree - < 2.5 degrees; Temporal_Resolution=1 month; Temporal_Resolution_Range=Monthly - < Annual].

CERES Monthly Gridded Single Satellite Fluxes and Clouds (FSW) in HDF (CER_FSW_Terra-FM1-MODIS_Edition2C)

NASA Technical Reports Server (NTRS)

Wielicki, Bruce A. (Principal Investigator); Barkstrom, Bruce R. (Principal Investigator)

The Monthly Gridded Radiative Fluxes and Clouds (FSW) product contains a month of space and time averaged Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The FSW is also produced for combinations of scanner instruments. All instantaneous fluxes from the CERES CRS product for a month are sorted by 1-degree spatial regions and by the Universal Time (UT) hour of observation. The mean of the instantaneous fluxes for a given region-hour bin is determined and recorded on the FSW along with other flux statistics and scene information. The mean adjusted fluxes at the four atmospheric levels defined by CRS are also included for both clear-sky and total-sky scenes. In addition, four cloud height categories are defined by dividing the atmosphere into four intervals with boundaries at the surface, 700-, 500-, 300-hPa, and the Top-of-the-Atmosphere (TOA). The cloud layers from CRS are put into one of the cloud height categories and averaged over the region. The cloud properties are also column averaged and included on the FSW. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-01-01; Stop_Date=2005-12-31] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Latitude_Resolution=1 degree; Longitude_Resolution=1 degree; Horizontal_Resolution_Range=100 km - < 250 km or approximately 1 degree - < 2.5 degrees; Temporal_Resolution=1 month; Temporal_Resolution_Range=Monthly - < Annual].

CERES) Monthly Gridded Single Satellite Fluxes and Clouds (FSW) in HDF (CER_FSW_Terra-FM2-MODIS_Edition2C)

NASA Technical Reports Server (NTRS)

Wielicki, Bruce A. (Principal Investigator); Barkstrom, Bruce R. (Principal Investigator)

The Monthly Gridded Radiative Fluxes and Clouds (FSW) product contains a month of space and time averaged Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The FSW is also produced for combinations of scanner instruments. All instantaneous fluxes from the CERES CRS product for a month are sorted by 1-degree spatial regions and by the Universal Time (UT) hour of observation. The mean of the instantaneous fluxes for a given region-hour bin is determined and recorded on the FSW along with other flux statistics and scene information. The mean adjusted fluxes at the four atmospheric levels defined by CRS are also included for both clear-sky and total-sky scenes. In addition, four cloud height categories are defined by dividing the atmosphere into four intervals with boundaries at the surface, 700-, 500-, 300-hPa, and the Top-of-the-Atmosphere (TOA). The cloud layers from CRS are put into one of the cloud height categories and averaged over the region. The cloud properties are also column averaged and included on the FSW. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-01-01; Stop_Date=2001-10-31] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Latitude_Resolution=1 degree; Longitude_Resolution=1 degree; Horizontal_Resolution_Range=100 km - < 250 km or approximately 1 degree - < 2.5 degrees; Temporal_Resolution=1 month; Temporal_Resolution_Range=Monthly - < Annual].

Research on regional numerical weather prediction

NASA Technical Reports Server (NTRS)

Kreitzberg, C. W.

1976-01-01

Extension of the predictive power of dynamic weather forecasting to scales below the conventional synoptic or cyclonic scales in the near future is assessed. Lower costs per computation, more powerful computers, and a 100 km mesh over the North American area (with coarser mesh extending beyond it) are noted at present. Doubling the resolution even locally (to 50 km mesh) would entail a 16-fold increase in costs (including vertical resolution and halving the time interval), and constraints on domain size and length of forecast. Boundary conditions would be provided by the surrounding 100 km mesh, and time-varying lateral boundary conditions can be considered to handle moving phenomena. More physical processes to treat, more efficient numerical techniques, and faster computers (improved software and hardware) backing up satellite and radar data could produce further improvements in forecasting in the 1980s. Boundary layer modeling, initialization techniques, and quantitative precipitation forecasting are singled out among key tasks.

Properties of Spectral Shapes of Whistler-Mode Emissions

NASA Astrophysics Data System (ADS)

Macusova, E.; Santolik, O.; Pickett, J. S.; Gurnett, D. A.; Cornilleau-Wehrlin, N.

2014-12-01

Whistler-mode emissions play an important role in wave-particle interactions occurring in the radiation belt region. Whistler mode chorus emissions consist of discrete wave packets which exhibit different spectral shapes. Rising tones (events with positive value of the frequency sweep rate) are frequently observed. Other categories of chorus spectral shapes, such as falling tones, hooks, broadband patterns, are also known. Whistler-mode emissions can additionally occur as hiss or combinations of hiss with discrete patterns. In this study, we have analyzed more than 11 years of high-time resolution measurements provided by the Wideband Data (WBD) instrument onboard four Cluster spacecraft to identify different spectral shapes of whistler mode emissions. We determine the distribution of individual groups of chorus spectral shapes in the Earth's magnetosphere and the effect of the different geomagnetic conditions on their occurrence. We focus on average polarization and propagation properties of the different types of spectral shapes, obtained during visually identified time intervals from multicomponent measurements of the STAFF-SA instrument recorded with a time resolution of 4 seconds.

Functional Analysis of Internal Moving Organs Using Super-Resolution Echography

NASA Astrophysics Data System (ADS)

Masuda, Kohji; Ishihara, Ken; Nagakura, Toshiaki; Tsuda, Takao; Furukawa, Toshiyuki; Maeda, Hajime; Kumagai, Sadatoshi; Kodama, Shinzo

1994-05-01

We have developed super-resolution echography to visualize instantaneous velocity and acceleration of internal organs from time-series echograms recorded by a high-frame-rate echograph. The algorithm for this method involves subtraction of two echograms, dividing the difference by the brightness gradient of the first echogram, and normalization of that result by the time interval between the two echograms. Velocity or acceleration is classified into some suitable colors and superimposed on the original B-mode image. Functional diagnosis of moving organs can be made by visualizing instantaneous velocity. In the case of the heart, hypokinesis can be distinguished from a normal heart by the value and the variation of colored parts representing instantaneous velocity. This can also be applied to the liver to observe pulsatile motion. By visualizing instantaneous acceleration, increase or decrease of velocity can be detected. Throb timing and the location of arrhythmia in a heart can be observed. This method has the possibility of contributing to noninvasive functional and characteristic evaluation.

Failed Deglutitive Upper Esophageal Sphincter Relaxation Is a Risk Factor for Aspiration in Stroke Patients with Oropharyngeal Dysphagia.

PubMed

Lee, Taeheon; Park, Jung Ho; Sohn, Chongil; Yoon, Kyung Jae; Lee, Yong-Taek; Park, Jung Hwan; Jung, Il Seok

2017-01-30

We attempted to examine the relationship between abnormal findings on high-resolution manometry (HRM) and videofluoroscopic swallowing study (VFSS) of the pharynx and upper esophageal sphincter (UES), and to identify the risk factors for aspiration. We performed VFSS and HRM on the same day in 36 ischemic stroke patients (mean age, 67.5 years) with dysphagia. Pressure (basal, median intra bolus, and nadir), relaxation time interval of the UES, and mesopharyngeal and hypopharyngeal contractility (as a contractile integral) were examined using HRM. The parameters of VFSS were vallecular residue, pyriform sinus residue, vallecular overflow, penetration, and aspiration. The association between the parameters of VFSS and HRM was analyzed by the Student's t test. Three (8.3%) and 4 (11.1%) stroke patients with dysphagia had pyriform sinus residue and vallecular sinus residue, respectively, and 5 (13.8%) patients showed aspiration. Mesopharyngeal and hypopharyngeal contractile integrals in patients with residue in the pyriform sinus were significantly lower than those in patients without residue in the pyriform sinus ( P < 0.05). Relaxation time intervals in patients with aspiration were significantly shorter than those in patients without aspiration ( P < 0.05), and multivariate regression analysis revealed a shorter relaxation time interval as the main risk factor for aspiration (OR, 0.03; 95% CI, 0.01-0.65; P < 0.05). Manometric measurements of the pharynx and UES were well correlated with abnormal findings in the VFSS, and a shorter relaxation time interval of the UES during deglutition is an important parameter for the development of aspiration.

Communication: Coordinate-dependent diffusivity from single molecule trajectories

NASA Astrophysics Data System (ADS)

Berezhkovskii, Alexander M.; Makarov, Dmitrii E.

2017-11-01

Single-molecule observations of biomolecular folding are commonly interpreted using the model of one-dimensional diffusion along a reaction coordinate, with a coordinate-independent diffusion coefficient. Recent analysis, however, suggests that more general models are required to account for single-molecule measurements performed with high temporal resolution. Here, we consider one such generalization: a model where the diffusion coefficient can be an arbitrary function of the reaction coordinate. Assuming Brownian dynamics along this coordinate, we derive an exact expression for the coordinate-dependent diffusivity in terms of the splitting probability within an arbitrarily chosen interval and the mean transition path time between the interval boundaries. This formula can be used to estimate the effective diffusion coefficient along a reaction coordinate directly from single-molecule trajectories.

Estimation of Rainfall Erosivity via 1-Minute to Hourly Rainfall Data from Taipei, Taiwan

NASA Astrophysics Data System (ADS)

Huang, Ting-Yin; Yang, Ssu-Yao; Jan, Chyan-Deng

2017-04-01

Soil erosion is a natural process on hillslopes that threats people's life and properties, having a considerable environmental and economic implications for soil degradation, agricultural activity and water quality. The rainfall erosivity factor (R-factor) in the Universal Soil Loss Equation (USLE), composed of total kinetic energy (E) and the maximum 30-min rainfall intensity (I30), is widely used as an indicator to measure the potential risks of soil loss caused by rainfall at a regional scale. This R factor can represent the detachment and entrainment involved in climate conditions on hillslopes, but lack of 30-min rainfall intensity data usually lead to apply this factor more difficult in many regions. In recent years, fixed-interval, hourly rainfall data is readily available and widely used due to the development of automatic weather stations. Here we assess the estimations of R, E, and I30 based on 1-, 5-, 10-, 15-, 30-, 60-minute rainfall data, and hourly rainfall data obtained from Taipei weather station during 2004 to 2010. Results show that there is a strong correlation among R-factors estimated from different interval rainfall data. Moreover, the shorter time-interval rainfall data (e.g., 1-min) yields larger value of R-factor. The conversion factors of rainfall erosivity (ratio of values estimated from the resolution lower than 30-min rainfall data to those estimated from 60-min and hourly rainfall data, respectively) range from 1.85 to 1.40 (resp. from 1.89 to 1.02) for 60-min (resp. hourly) rainfall data as the time resolution increasing from 30-min to 1-min. This paper provides useful information on estimating R-factor when hourly rainfall data is only available.

Drug therapy for solitary cysticercus granuloma: a systematic review and meta-analysis.

PubMed

Otte, Willem M; Singla, Monika; Sander, Josemir W; Singh, Gagandeep

2013-01-08

The effectiveness of anthelminthic and corticosteroid drug therapy in parenchymal neurocysticercosis is well established. The treatment of parenchymal solitary cysticercus granuloma (SCG), however, remains controversial. We attempted to obtain a consistent estimate of the efficacy of anthelminthic and corticosteroid drug treatment in SCG. Randomized-controlled trials (RCTs) comparing rates of seizure freedom, granuloma resolution, and residual calcification in individuals with SCG treated with anthelminthic or corticosteroid drugs with those treated with antiepileptic drugs (AEDs) alone were systematically reviewed and quantified using fixed- or random-effects meta-analysis. Fifteen RCTs were identified for inclusion. Ten RCTs assigned 765 people with SCG to AED treatment with or without anthelminthic drug (albendazole) treatment. A further 5 RCTs assigned 457 people with SCG to AED treatment with or without corticosteroid drugs. Anthelminthic treatment was associated with significantly increased rates of seizure freedom (nonevent odds ratio: 2.45; 95% confidence interval: 1.49-4.03; p = 0.0004) and significantly higher rates of granuloma resolution (odds ratio: 2.09; 95% confidence interval: 1.41-3.00; p = 0.0003), but did not alter the risk of residual calcification. Corticosteroid treatment was not significantly associated with any outcome. Anthelminthic treatment with albendazole provides improved rates of seizure freedom and hastens resolution of the granuloma. The role of corticosteroid treatment remains uncertain. The benefits (or lack thereof in the case of corticosteroids) are consistent when measured across different time points after treatment.

Detecting Blind Fault with Fractal and Roughness Factors from High Resolution LiDAR DEM at Taiwan

NASA Astrophysics Data System (ADS)

Cheng, Y. S.; Yu, T. T.

2014-12-01

There is no obvious fault scarp associated with blind fault. The traditional method of mapping this unrevealed geological structure is the cluster of seismicity. Neither the seismic event nor the completeness of cluster could be captured by network to chart the location of the entire possible active blind fault within short period of time. High resolution DEM gathered by LiDAR could denote actual terrain information despite the existence of plantation. 1-meter interval DEM of mountain region at Taiwan is utilized by fractal, entropy and roughness calculating with MATLAB code. By jointing these handing, the regions of non-sediment deposit are charted automatically. Possible blind fault associated with Chia-Sen earthquake at southern Taiwan is served as testing ground. GIS layer help in removing the difference from various geological formation, then multi-resolution fractal index is computed around the target region. The type of fault movement controls distribution of fractal index number. The scale of blind fault governs degree of change in fractal index. Landslide induced by rainfall and/or earthquake possesses larger degree of geomorphology alteration than blind fault; special treatment in removing these phenomena is required. Highly weathered condition at Taiwan should erase the possible trace remained upon DEM from the ruptured of blind fault while reoccurrence interval is higher than hundreds of years. This is one of the obstacle in finding possible blind fault at Taiwan.

A single-sweep, nanosecond time resolution laser temperature-jump apparatus

NASA Astrophysics Data System (ADS)

Ballew, R. M.; Sabelko, J.; Reiner, C.; Gruebele, M.

1996-10-01

We describe a fast temperature-jump (T-jump) apparatus capable of acquiring kinetic relaxation transients via real-time fluorescence detection over a time interval from nanoseconds to milliseconds in a single sweep. The method is suitable for aqueous solutions, relying upon the direct absorption of laser light by the bulk water. This obviates the need for additives (serving as optical or conductive heaters) that may interact with the sample under investigation. The longitudinal temperature profile is made uniform by counterpropagating heating pulses. Dead time is limited to one period of the probe laser (16 ns). The apparatus response is tested with aqueous tryptophan and the diffusion-controlled dimerization of proflavine.

Determining probability distribution of coherent integration time near 133 Hz and 1346 km in the Pacific Ocean.

PubMed

Spiesberger, John L

2013-02-01

The hypothesis tested is that internal gravity waves limit the coherent integration time of sound at 1346 km in the Pacific ocean at 133 Hz and a pulse resolution of 0.06 s. Six months of continuous transmissions at about 18 min intervals are examined. The source and receiver are mounted on the bottom of the ocean with timing governed by atomic clocks. Measured variability is only due to fluctuations in the ocean. A model for the propagation of sound through fluctuating internal waves is run without any tuning with data. Excellent resemblance is found between the model and data's probability distributions of integration time up to five hours.

Global Ionosphere Perturbations Monitored by the Worldwide GPS Network

NASA Technical Reports Server (NTRS)

Ho, C. M.; Manucci, A. T.; Lindqwister, U. J.; Pi, X.

1996-01-01

For the first time, measurements from the Global Positioning System (GPS) worldwide network are employed to study the global ionospheric total electron content(TEC) changes during a magnetic storm (November 26, 1994). These measurements are obtained from more than 60 world-wide GPS stations which continuously receive dual-frequency signals. Based on the delays of the signals, we have generated high resolution global ionospheric maps (GIM) of TEC at 15 minute intervals. Using a differential method comparing storm time maps with quiet time maps, we find that significant TEC increases (the positive effect ) are the major feature in the winter hemisphere during this storm (the maximum percent change relative to quiet times is about 150 percent).

High-resolution speleothem record of precipitation from the Yucatan Peninsula spanning the Maya Preclassic Period

NASA Astrophysics Data System (ADS)

Medina-Elizalde, Martín; Burns, Stephen J.; Polanco-Martínez, Josué M.; Beach, Timothy; Lases-Hernández, Fernanda; Shen, Chuan-Chou; Wang, Hao-Cheng

2016-03-01

We produced a new high-resolution absolute U-Th dated stalagmite oxygen isotope record (δ18O) from Río Secreto, Playa del Carmen, Yucatan Peninsula (YP). This new 1434-year stalagmite record (named Itzamna after the Maya god of creation) spans the time interval between BCE 1037 and CE 397 with an average resolution of 8 ± 2 years. It provides a novel view of climate evolution over the Preclassic and early Classic periods in Maya history. To understand the controls of regional precipitation δ18O on seasonal time scales, we characterized the amount effect between precipitation amount (P) and precipitation δ18O (δP). We found that precipitation δ18O in the Yucatan Peninsula is controlled by the amount effect on seasonal scales (δP/ΔP = - 0.0137 ± 0.0031‰ per mm, r = 0.9), as suspected but never before demonstrated. Cave drip δ18O is consistent with the annual amount-weighted δ18O composition of precipitation. Multiple lines of evidence suggest that stalagmite δ18O reflects isotopic equilibrium conditions and thus stalagmite δ18O changes are interpreted to reflect precipitation amount. We determined quantitative precipitation changes from the stalagmite δ18O record following previous methods (Medina-Elizalde and Rohling, 2012). The stalagmite precipitation record suggests twelve periods of anomalous precipitation reductions ranging between about 30 and 70% below mean conditions at the time and with durations from 6 years to 31 years. Between BCE 520 and 166, the speleothem precipitation record suggests that the YP experienced an interval of high precipitation labeled the Late Preclassic Humid Period (LPHP) with precipitation maxima of up to + 86 ± 20%. Preclassic Maya cultural expansion in El Mirador Basin, located in northern Guatemala, took place while the peninsula transitioned from the LPHP to an interval with below average precipitation. We find that the Preclassic abandonment of major centers in the Mirador Basin and others around the Maya Lowlands was synchronous with two unprecedented multi-decadal events of severe precipitation reduction with magnitudes of - 55 ± 13% and - 49 ± 12 and centered at CE 186 and 234, respectively. We also find evidence that centennial scale precipitation variability in the YP during the Preclassic Period may have been associated with shifts in rainfall fluxes from Atlantic tropical cyclones.

High Resolution Simulations of Future Climate in West Africa Using a Variable-Resolution Atmospheric Model

NASA Astrophysics Data System (ADS)

Adegoke, J. O.; Engelbrecht, F.; Vezhapparambu, S.

2013-12-01

In previous work demonstrated the application of a var¬iable-resolution global atmospheric model, the conformal-cubic atmospheric model (CCAM), across a wide range of spatial and time scales to investigate the ability of the model to provide realistic simulations of present-day climate and plausible projections of future climate change over sub-Saharan Africa. By applying the model in stretched-grid mode the versatility of the model dynamics, numerical formulation and physical parameterizations to function across a range of length scales over the region of interest, was also explored. We primarily used CCAM to illustrate the capability of the model to function as a flexible downscaling tool at the climate-change time scale. Here we report on additional long term climate projection studies performed by downscaling at much higher resolutions (8 Km) over an area that stretches from just south of Sahara desert to the southern coast of the Niger Delta and into the Gulf of Guinea. To perform these simulations, CCAM was provided with synoptic-scale forcing of atmospheric circulation from 2.5 deg resolution NCEP reanalysis at 6-hourly interval and SSTs from NCEP reanalysis data uses as lower boundary forcing. CCAM 60 Km resolution downscaled to 8 Km (Schmidt factor 24.75) then 8 Km resolution simulation downscaled to 1 Km (Schmidt factor 200) over an area approximately 50 Km x 50 Km in the southern Lake Chad Basin (LCB). Our intent in conducting these high resolution model runs was to obtain a deeper understanding of linkages between the projected future climate and the hydrological processes that control the surface water regime in this part of sub-Saharan Africa.

[Winter wheat area estimation with MODIS-NDVI time series based on parcel].

PubMed

Li, Le; Zhang, Jin-shui; Zhu, Wen-quan; Hu, Tan-gao; Hou, Dong

2011-05-01

Several attributes of MODIS (moderate resolution imaging spectrometer) data, especially the short temporal intervals and the global coverage, provide an extremely efficient way to map cropland and monitor its seasonal change. However, the reliability of their measurement results is challenged because of the limited spatial resolution. The parcel data has clear geo-location and obvious boundary information of cropland. Also, the spectral differences and the complexity of mixed pixels are weak in parcels. All of these make that area estimation based on parcels presents more advantage than on pixels. In the present study, winter wheat area estimation based on MODIS-NDVI time series has been performed with the support of cultivated land parcel in Tongzhou, Beijing. In order to extract the regional winter wheat acreage, multiple regression methods were used to simulate the stable regression relationship between MODIS-NDVI time series data and TM samples in parcels. Through this way, the consistency of the extraction results from MODIS and TM can stably reach up to 96% when the amount of samples accounts for 15% of the whole area. The results shows that the use of parcel data can effectively improve the error in recognition results in MODIS-NDVI based multi-series data caused by the low spatial resolution. Therefore, with combination of moderate and low resolution data, the winter wheat area estimation became available in large-scale region which lacks completed medium resolution images or has images covered with clouds. Meanwhile, it carried out the preliminary experiments for other crop area estimation.

The Rotator Interval – A Link Between Anatomy and Ultrasound

PubMed Central

Tamborrini, Giorgio; Möller, Ingrid; Bong, David; Miguel, Maribel; Marx, Christian; Müller, Andreas Marc; Müller-Gerbl, Magdalena

2017-01-01

Shoulder pathologies of the rotator cuff of the shoulder are common in clinical practice. The focus of this pictorial essay is to discuss the anatomical details of the rotator interval of the shoulder, correlate the anatomy with normal ultrasound images and present selected pathologies. We focus on the imaging of the rotator interval that is actually the anterosuperior aspect of the glenohumeral joint capsule that is reinforced externally by the coracohumeral ligament, internally by the superior glenohumeral ligament and capsular fibers which blend together and insert medially and laterally to the bicipital groove. In this article we demonstrate the capability of high-resolution musculoskeletal ultrasound to visualize the detailed anatomy of the rotator interval. MSUS has a higher spatial resolution than other imaging techniques and the ability to examine these structures dynamically and to utilize the probe for precise anatomic localization of the patient’s pain by sono-palpation. PMID:28845477

The Rotator Interval - A Link Between Anatomy and Ultrasound.

PubMed

Tamborrini, Giorgio; Möller, Ingrid; Bong, David; Miguel, Maribel; Marx, Christian; Müller, Andreas Marc; Müller-Gerbl, Magdalena

2017-06-01

Shoulder pathologies of the rotator cuff of the shoulder are common in clinical practice. The focus of this pictorial essay is to discuss the anatomical details of the rotator interval of the shoulder, correlate the anatomy with normal ultrasound images and present selected pathologies. We focus on the imaging of the rotator interval that is actually the anterosuperior aspect of the glenohumeral joint capsule that is reinforced externally by the coracohumeral ligament, internally by the superior glenohumeral ligament and capsular fibers which blend together and insert medially and laterally to the bicipital groove. In this article we demonstrate the capability of high-resolution musculoskeletal ultrasound to visualize the detailed anatomy of the rotator interval. MSUS has a higher spatial resolution than other imaging techniques and the ability to examine these structures dynamically and to utilize the probe for precise anatomic localization of the patient's pain by sono-palpation.

Hierarchical Spatio-temporal Visual Analysis of Cluster Evolution in Electrocorticography Data

DOE PAGES

Murugesan, Sugeerth; Bouchard, Kristofer; Chang, Edward; ...

2016-10-02

Here, we present ECoG ClusterFlow, a novel interactive visual analysis tool for the exploration of high-resolution Electrocorticography (ECoG) data. Our system detects and visualizes dynamic high-level structures, such as communities, using the time-varying spatial connectivity network derived from the high-resolution ECoG data. ECoG ClusterFlow provides a multi-scale visualization of the spatio-temporal patterns underlying the time-varying communities using two views: 1) an overview summarizing the evolution of clusters over time and 2) a hierarchical glyph-based technique that uses data aggregation and small multiples techniques to visualize the propagation of clusters in their spatial domain. ECoG ClusterFlow makes it possible 1) tomore » compare the spatio-temporal evolution patterns across various time intervals, 2) to compare the temporal information at varying levels of granularity, and 3) to investigate the evolution of spatial patterns without occluding the spatial context information. Lastly, we present case studies done in collaboration with neuroscientists on our team for both simulated and real epileptic seizure data aimed at evaluating the effectiveness of our approach.« less

General Relativity without paradigm of space-time covariance, and resolution of the problem of time

NASA Astrophysics Data System (ADS)

Soo, Chopin; Yu, Hoi-Lai

2014-01-01

The framework of a theory of gravity from the quantum to the classical regime is presented. The paradigm shift from full space-time covariance to spatial diffeomorphism invariance, together with clean decomposition of the canonical structure, yield transparent physical dynamics and a resolution of the problem of time. The deep divide between quantum mechanics and conventional canonical formulations of quantum gravity is overcome with a Schrödinger equation for quantum geometrodynamics that describes evolution in intrinsic time. Unitary time development with gauge-invariant temporal ordering is also viable. All Kuchar observables become physical; and classical space-time, with direct correlation between its proper times and intrinsic time intervals, emerges from constructive interference. The framework not only yields a physical Hamiltonian for Einstein's theory, but also prompts natural extensions and improvements towards a well behaved quantum theory of gravity. It is a consistent canonical scheme to discuss Horava-Lifshitz theories with intrinsic time evolution, and of the many possible alternatives that respect 3-covariance (rather than the more restrictive 4-covariance of Einstein's theory), Horava's "detailed balance" form of the Hamiltonian constraint is essentially pinned down by this framework. Issues in quantum gravity that depend on radiative corrections and the rigorous definition and regularization of the Hamiltonian operator are not addressed in this work.

VizieR Online Data Catalog: BVRI photometry of S5 0716+714 in 2012 (Hong+, 2017)

NASA Astrophysics Data System (ADS)

Hong, S.; Xiong, D.; Bai, J.

2017-10-01

Our optical observations were carried out using the 60cm BOOTES-4 auto-telescope that is located at the Lijiang Observatory of the Yunnan Observatories of the Chinese Academy of Sciences, where the longitude is 100°01'51''E and the latitude is 26°42'32''N, with an altitude of 3193m. The telescope's main objective is to observe gamma-ray bursts and blazars. During our observations (2012 Jan 27-2012 Feb 08), the telescope was equipped with standard Johnson UBV and Cousins RI filters. The optical observations in the B, V, R, and I bands were in a corresponding cyclic mode. Time resolutions for most of the nights are less than 6 minutes, and time spans on a night are more than 5hr. The time intervals between the V and R bands range from 30 to 131s, and most of the nights have time intervals less than 50s. The typical exposure times in the B, V, R, and I bands are 60, 40, 40, and 40s, respectively. Please refer to Section 2 in the paper for additional details about the observations. (6 data files).

Towards an Accurate Orbital Calibration of Late Miocene Climate Events: Insights From a High-Resolution Chemo- and Magnetostratigraphy (8-6 Ma) from Equatorial Pacific IODP Sites U1337 and U1338

NASA Astrophysics Data System (ADS)

Drury, A. J.; Westerhold, T.; Frederichs, T.; Wilkens, R.; Channell, J. E. T.; Evans, H. F.; Hodell, D. A.; John, C. M.; Lyle, M. W.; Roehl, U.; Tian, J.

2015-12-01

In the 8-6 Ma interval, the late Miocene is characterised by a long-term -0.3 ‰ reduction in benthic foraminiferal δ18O and distinctive short-term δ18O cycles, possibly related to dynamic Antarctic ice sheet variability. In addition, the late Miocene carbon isotope shift (LMCIS) marks a permanent long-term -1 ‰ shift in oceanic δ13CDIC, which is the largest, long-term perturbation in the global marine carbon cycle since the mid Miocene Monterey excursion. Accurate age control is crucial to investigate the origin of the δ18O cyclicity and determine the precise onset of the LMCIS. The current Geological Time Scale in the 8-6 Ma interval is constructed using astronomical tuning of sedimentary cycles in Mediterranean outcrops. However, outside of the Mediterranean, a comparable high-resolution chemo-, magneto-, and cyclostratigraphy at a single DSDP/ODP/IODP site does not exist. Generating an accurate astronomically-calibrated chemo- and magneto-stratigraphy in the 8-6 Ma interval became possible with retrieval of equatorial Pacific IODP Sites U1337 and U1338, as both sites have sedimentation rates ~2 cm/kyr, high biogenic carbonate content, and magnetic polarity stratigraphies. Here we present high-resolution correlation of Sites U1337 and U1338 using Milankovitch-related cycles in core images and X-ray fluorescence core scanning data. By combining inclination and declination data from ~400 new discrete samples with shipboard measurements, we are able to identify 14 polarity reversals at Site U1337 from the young end of Chron C3An.1n (~6.03 Ma) to the onset of Chron C4n.2n (~8.11 Ma). New high-resolution (<1.5 kyr) stable isotope records from Site U1337 correlate highly with Site U1338 records, enabling construction of a high-resolution stack. Initial orbital tuning of the U1337-U1338 records show that the δ18O cyclicity is obliquity driven, indicating high-latitude climate forcing. The LMCIS starts ~7.55 Ma and is anchored in Chron C4n.1n, which is comparable to the north and equatorial Atlantic.

Differential effects of phasic and tonic alerting on the efficiency of executive attention.

PubMed

Asanowicz, Dariusz; Marzecová, Anna

2017-05-01

The study examined how alerting and executive attention interact in a task involving conflict resolution. We proposed a tentative scenario in which an initial exogenous phasic alerting phase is followed by an endogenous tonic alerting phase, and hypothesized that these two processes may have distinct effects on conflict resolution. Phasic alerting was expected to increase the conflict, whereas tonic alerting was expected to decrease the conflict. Three experiments were conducted using different variants of the flanker task with visual alerting cues and varied cue-target intervals (SOA), to differentiate between effects of phasic alerting (short SOA) and tonic alerting (long SOA). The results showed that phasic alerting consistently decreased the efficiency of conflict resolution indexed by response time and accuracy, whereas tonic alerting increased the accuracy of conflict resolution, but at a cost in the speed of processing the conflict. The third experiment additionally showed that the effects of phasic alerting may be modulated by the psychophysical strength of alerting cues. Discussed are possible mechanisms that could account for the observed interactions between alerting and conflict resolution, as well as some discrepancies between the current and previous studies. Copyright © 2017 Elsevier B.V. All rights reserved.

High-resolution paleoclimatology of the Santa Barbara Basin during the Medieval Climate Anomaly and early Little Ice Age based on diatom and silicoflagellate assemblages in Kasten core SPR0901-02KC

USGS Publications Warehouse

Barron, John A.; Bukry, David B.; Hendy, Ingrid L.

2015-01-01

Diatom and silicoflagellate assemblages documented in a high-resolution time series spanning 800 to 1600 AD in varved sediment recovered in Kasten core SPR0901-02KC (34°16.845’ N, 120°02.332’ W, water depth 588 m) from the Santa Barbara Basin (SBB) reveal that SBB surface water conditions during the Medieval Climate Anomaly (MCA) and the early part of the Little Ice Age (LIA) were not extreme by modern standards, mostly falling within one standard deviation of mean conditions during the pre anthropogenic interval of 1748 to 1900. No clear differences between the character of MCA and the early LIA conditions are apparent. During intervals of extreme droughts identified by terrigenous proxy scanning XRF analyses, diatom and silicoflagellate proxies for coastal upwelling typically exceed one standard deviation above mean values for 1748-1900, supporting the hypothesis that droughts in southern California are associated with cooler (or La Niña-like) sea surface temperatures (SSTs). Increased percentages of diatoms transported downslope generally coincide with intervals of increased siliciclastic flux to the SBB identified by scanning XRF analyses. Diatom assemblages suggest only two intervals of the MCA (at ~897 to 922 and ~1151 to 1167) when proxy SSTs exceeded one standard deviation above mean values for 1748 to 1900. Conversely, silicoflagellates imply extreme warm water events only at ~830 to 860 (early MCA) and ~1360 to 1370 (early LIA) that are not supported by the diatom data. Silicoflagellates appear to be more suitable for characterizing average climate during the 5 to 11 year-long sample intervals studied in the SPR0901-02KC core than diatoms, probably because diatom relative abundances may be dominated by seasonal blooms of a particular year.

Impact locations and concussion outcomes in high school football player-to-player collisions.

PubMed

Kerr, Zachary Y; Collins, Christy L; Mihalik, Jason P; Marshall, Stephen W; Guskiewicz, Kevin M; Comstock, R Dawn

2014-09-01

Little research has examined concussion outcomes in terms of impact location (ie, the area on the head in which the impact occurred). This study describes the epidemiology of concussions resulting from player-to-player collision in high school football by impact location. National High School Sports-Related Injury Surveillance Study data (2008/2009-2012/2013) were analyzed to calculate rates and describe circumstances of football concussion (eg, symptomology, symptom resolution time, return to play) resulting from player-to-player collisions by impact location (ie, front-, back-, side-, and top-of-the-head). Most concussions resulting from player-to-player collisions occurred from front-of-the-head (44.7%) and side-of-the-head (22.3%) impacts. Number of symptoms reported, prevalence of reported symptoms, symptom resolution time, and length of time to return to play were not associated with impact location. However, a larger proportion of football players sustaining concussions from top-of-the-head impacts experienced loss of consciousness (8.0%) than those sustaining concussions from impacts to other areas of the head (3.5%) (injury proportion ratio 2.3; 95% confidence interval 1.2-4.2; P = .008). Players had their head down at the time of impact in a higher proportion of concussions caused by top-of-the-head impacts (86.4%) than concussions from impacts to other areas of the head (24.0%) (injury proportion ratio 3.6; 95% confidence interval 3.2-4.0; P < .001). Among high school football players who sustained concussions due to player-to-player collisions, concussion outcomes were generally independent of impact location. Recommended strategies for reducing the proportion of top-of-the-head impacts include improved education regarding tackling with proper "head-up" technique. Copyright © 2014 by the American Academy of Pediatrics.

A high resolution, one million year record of extraterrestrial 3Helium from the Shatsky Rise (site 1209) following the K/T impact

NASA Astrophysics Data System (ADS)

Bhattacharya, A.; Mukhopadhyay, S.; Hull, P. M.; Norris, R. D.

2010-12-01

Located in the North Pacific Ocean, site 1209 on the Shatsky rise offers one of the best-preserved sections for studying biological, oceanographic and climatic events in the aftermath of the K-T impact at ~65 Ma. At this site, the first 450 kyrs after the boundary is represented by an extended carbonate section [1]. The expanded section, also known as the ‘strange interval’ [1] is in direct contrast to sites in the Atlantic and Indian Ocean that have low carbonate deposition during this interval. The strange interval is important for evaluating the immediate changes in climate, ocean circulation, and evolutionary dynamics that accompanied K-T impact in the Pacific Ocean. Here we present measurements of extraterrestrial 3He at site 1209 for the first one million year following the K-T impact event at a resolution of 2.5 cm. Our goal is to better constrain the timescale of climatic and biotic events during this interval of time. Accumulation rates of interplanetary dust particles (IDPs), as traced by extraterrestrial 3He [2], provide a tool with which to investigate sedimentation rates at high resolution. Prior work has shown that the accretion rate of IDPs across the K-T boundary is constant [2], allowing us to invert the extraterrestrial 3He flux for instantaneous sedimentation rates. Sedimentation rates derived from extraterrestrial 3He for the first 1.91 meters i.e. 261.60-259.72 revised composite meters depth (rmcd) following the K-T impact are on an average 0.48 cm/kyr- a factor of 1.6 lower than previously suggested [1]. For a brief period, between 259.69-259.44 rmcd after the K/T boundary, 3He-based sedimentation rates increase sharply to 2.88cm/kyr—a factor of 4.23 higher than has been reported for the same time interval [1]. The short lived increase in sedimentation rate may be explained by higher productivity and/or better carbonate preservation through a deepening lysocline. The 3He based sedimentation rates indicate that the duration of the ‘strange interval’ is 721 kyrs and not 450 kyrs as previously suggested based on astronomical tuning [1]. Hence, our results indicate that there are significant differences between the astronomically tuned timescale [1] and the 3He-derived timescale over the first million years following the K-T impact event. [1] Westerhold et al. Paleogeography, paleoclimatology,paleoecology vol 257. pp373. 2008. [2] Mukhopadhyay et al. Geochimica Cosmochimica Acta. Vol 65. pp 653. 2001.

A catalog of atmospheric densities from the drag on five balloon satellites

NASA Technical Reports Server (NTRS)

Jacchia, L. G.; Slowey, J. W.

1975-01-01

A catalog of atmospheric densities derived for the drag on five balloon satellites is presented. Much of the catalog was based on precisely reduced Baker-Nunn observations and, for that reason, provides much improved time resolution. The effect of direct solar radiation pressure was precisely evaluated, and that of terrestrial radiation pressure was included in every case. The interval covered for each satellite varies between 3.1 and 7.6 years, with the data extending from early 1961 to early 1973.

The JET neutron time-of-flight spectrometer

NASA Astrophysics Data System (ADS)

Elevant, T.; Aronsson, D.; van Belle, P.; Grosshoeg, G.; Hoek, M.; Olsson, M.; Sadler, G.

1991-08-01

An instrument for measuring neutron energy spectra over the interval 1 to 20 MeV has been developed and tested. It is based on time-of-flight measurements in between correlated events in two spatially separated sets of plastic scintillators. This instrument has been installed at the Joint European Tours (JET). We describe here the required operating conditions, performance tests and results of three years of operation during which neutron energy spectra in the 2-3 MeV range from D(d, n) 3He reactions in JET were studied. Some technical details are given and the results from Monte Carlo and analytical model calculations of the spectrometer energy resolution and response function are presented. The efficiency of the system is ≈ 1 × 10 -2 cm 2 counted at the position of the first detector. Together with the geometry conditions at JET this yields 6 × 10 2 counts per 10 15 neutrons emitted. The energy resolution is in the interval from 125 to 133 keV (FWHM) depending on conditions and is known to an accuracy of ±5 keV. Correction for the inevitable random background is dealt with in detail and a reduction procedure valid for fast variations in neutron count-rates is provided. Plasma ion temperatures deduced from the neutron spectra agree within statistical limits with the results from other diagnostic techniques in use at JET. Stable behaviour up to useful count-rates of 3 × 10 3 counts/s have been obtained, making possible the study of neutron spectra on the short time-scales typical of fusion plasmas.

Failed Deglutitive Upper Esophageal Sphincter Relaxation Is a Risk Factor for Aspiration in Stroke Patients with Oropharyngeal Dysphagia

PubMed Central

Lee, Taeheon; Park, Jung Ho; Sohn, Chongil; Yoon, Kyung Jae; Lee, Yong-Taek; Park, Jung Hwan; Jung, Il Seok

2017-01-01

Background/Aims We attempted to examine the relationship between abnormal findings on high-resolution manometry (HRM) and videofluoroscopic swallowing study (VFSS) of the pharynx and upper esophageal sphincter (UES), and to identify the risk factors for aspiration. Methods We performed VFSS and HRM on the same day in 36 ischemic stroke patients (mean age, 67.5 years) with dysphagia. Pressure (basal, median intra bolus, and nadir), relaxation time interval of the UES, and mesopharyngeal and hypopharyngeal contractility (as a contractile integral) were examined using HRM. The parameters of VFSS were vallecular residue, pyriform sinus residue, vallecular overflow, penetration, and aspiration. The association between the parameters of VFSS and HRM was analyzed by the Student’s t test. Results Three (8.3%) and 4 (11.1%) stroke patients with dysphagia had pyriform sinus residue and vallecular sinus residue, respectively, and 5 (13.8%) patients showed aspiration. Mesopharyngeal and hypopharyngeal contractile integrals in patients with residue in the pyriform sinus were significantly lower than those in patients without residue in the pyriform sinus (P < 0.05). Relaxation time intervals in patients with aspiration were significantly shorter than those in patients without aspiration (P < 0.05), and multivariate regression analysis revealed a shorter relaxation time interval as the main risk factor for aspiration (OR, 0.03; 95% CI, 0.01–0.65; P < 0.05). Conclusions Manometric measurements of the pharynx and UES were well correlated with abnormal findings in the VFSS, and a shorter relaxation time interval of the UES during deglutition is an important parameter for the development of aspiration. PMID:27510474

The Time Dependent Propensity Function for Acceleration of Spatial Stochastic Simulation of Reaction-Diffusion Systems

PubMed Central

Wu, Sheng; Li, Hong; Petzold, Linda R.

2015-01-01

The inhomogeneous stochastic simulation algorithm (ISSA) is a fundamental method for spatial stochastic simulation. However, when diffusion events occur more frequently than reaction events, simulating the diffusion events by ISSA is quite costly. To reduce this cost, we propose to use the time dependent propensity function in each step. In this way we can avoid simulating individual diffusion events, and use the time interval between two adjacent reaction events as the simulation stepsize. We demonstrate that the new algorithm can achieve orders of magnitude efficiency gains over widely-used exact algorithms, scales well with increasing grid resolution, and maintains a high level of accuracy. PMID:26609185

Evaluation of a patient navigation program.

PubMed

Koh, Catherine; Nelson, Joan M; Cook, Paul F

2011-02-01

This study examined the value and effectiveness of a patient navigation program in terms of timeliness of access to cancer care, resolution of barriers, and satisfaction in 55 patients over a six-month period. Although not statistically significant, the time interval between diagnostic biopsy to first consultation with a cancer specialist after program implementation was reduced from an average of 14.6 days to 12.8 days. The time interval between diagnostic biopsy to initiation of cancer treatment also was reduced from 30 days to 26.2 days (not statistically significant). In addition, 71% of patient barriers were resolved by the time treatment was initiated. Overall, patients were highly satisfied with their navigated care experience. Consistent evaluation and monitoring of quality-of-care indicators are critical to further develop the program and to direct resource allocation. Oncology nurses participating in patient navigation programs should be encouraged to evaluate their importance and impact in this developing concept. Nurses should seek roles that allow them to optimize the effective use of their specialized knowledge and skills to the benefit of patients along the cancer care continuum.

Evaluation of the influence of acquisition and reconstruction parameters for 16-row multidetector CT on coronary calcium scoring using a stationary and dynamic cardiac phantom.

PubMed

Begemann, Philipp G C; van Stevendaal, Udo; Koester, Ralph; Mahnken, Andreas H; Koops, Andreas; Adam, Gerhard; Grass, Michael; Nolte-Ernsting, Claus

2007-08-01

A calcium-scoring phantom with hydroxyapatite-filled cylindrical holes (0.5 to 4 mm) was used. High-resolution scans were performed for an accuracy baseline. The phantom was mounted to a moving heart phantom. Non-moving data with the implementation of an ECG-signal were acquired for different pitches (0.2/0.3), heart rates (60/80/95 bpm) and collimations (16 x 0.75/16 x 1.5 mm). Images were reconstructed with a cone-beam multi-cycle algorithm at a standard thickness/increment of 3 mm/1.5 mm and the thinnest possible thickness (0.8/0.4 and 2/1). Subsequently, ECG-gated moving calcium-scoring phantom data were acquired. The calcium volume and Agatston score were measured. The temporal resolution and reconstruction cycles were calculated. High-resolution scans determine the calcium volume with a high accuracy (mean overestimation, 0.8%). In the non-moving measurements, the volume underestimation ranged from about 6% (16 x 0.75 mm; 0.8/0.4 mm) to nearly 25% (16 x 1.5 mm; 3/1.5 mm). Moving scans showed increased measurement errors depending on the reconstructed RR interval, collimation, pitch, heart rate and gantry rotation time. Also, a correlation with the temporal resolution could be found. The reliability of calcium-scoring results can be improved with the use of a narrower collimation, a lower pitch and the reconstruction of thinner images, resulting in higher patient doses. The choice of the correct cardiac phase within the RR interval is essential to minimize measurement errors.

High Temporal Resolution Measurements to Investigate Carbon Dynamics in Subtropical Peat Soils Using Automated Ground Penetrating Radar (GPR) Measurements at the Laboratory Scale

NASA Astrophysics Data System (ADS)

McClellan, M. D.; Wright, W. J.; Job, M. J.; Comas, X.

2015-12-01

Peatlands have the capability to produce and release significant amounts of free phase biogenic gasses (CO2, CH4) into the atmosphere and are thus regarded as key contributors of greenhouse gases into the atmosphere. Many studies throughout the past two decades have investigated gas flux dynamics in peat soils; however a high resolution temporal understanding in the variability of these fluxes (particularly at the matrix scale) is still lacking. This study implements an array of hydrogeophysical methods to investigate the temporal variability in biogenic gas accumulation and release in high resolution for a large 0.073 m3 peat monolith from the Blue Cypress Preserve in central Florida. An autonomous rail system was constructed in order to estimate gas content variability (i.e. build-up and release) within the peat matrix using a series of continuous, uninterrupted ground penetrating radar (GPR) transects along the sample. This system ran non-stop implementing a 0.01 m shot interval using high frequency (1.2 GHz) antennas. GPR measurements were constrained with an array of 6 gas traps fitted with time-lapse cameras in order to capture gas releases at 15 minute intervals. A gas chromatograph was used to determine CH4 and CO2 content of the gas collected in the gas traps. The aim of this study is to investigate the temporal variability in the accumulation and release of biogenic gases in subtropical peat soils at the lab scale at a high resolution. This work has implications for better understanding carbon dynamics in subtropical freshwater peatlands and how climate change may alter such dynamics.

A computational theory for the classification of natural biosonar targets based on a spike code.

PubMed

Müller, Rolf

2003-08-01

A computational theory for the classification of natural biosonar targets is developed based on the properties of an example stimulus ensemble. An extensive set of echoes (84 800) from four different foliages was transcribed into a spike code using a parsimonious model (linear filtering, half-wave rectification, thresholding). The spike code is assumed to consist of time differences (interspike intervals) between threshold crossings. Among the elementary interspike intervals flanked by exceedances of adjacent thresholds, a few intervals triggered by disjoint half-cycles of the carrier oscillation stand out in terms of resolvability, visibility across resolution scales and a simple stochastic structure (uncorrelatedness). They are therefore argued to be a stochastic analogue to edges in vision. A three-dimensional feature vector representing these interspike intervals sustained a reliable target classification performance (0.06% classification error) in a sequential probability ratio test, which models sequential processing of echo trains by biological sonar systems. The dimensions of the representation are the first moments of duration and amplitude location of these interspike intervals as well as their number. All three quantities are readily reconciled with known principles of neural signal representation, since they correspond to the centre of gravity of excitation on a neural map and the total amount of excitation.

Drug therapy for solitary cysticercus granuloma

PubMed Central

Singla, Monika; Sander, Josemir W.; Singh, Gagandeep

2013-01-01

Objective: The effectiveness of anthelminthic and corticosteroid drug therapy in parenchymal neurocysticercosis is well established. The treatment of parenchymal solitary cysticercus granuloma (SCG), however, remains controversial. We attempted to obtain a consistent estimate of the efficacy of anthelminthic and corticosteroid drug treatment in SCG. Methods: Randomized-controlled trials (RCTs) comparing rates of seizure freedom, granuloma resolution, and residual calcification in individuals with SCG treated with anthelminthic or corticosteroid drugs with those treated with antiepileptic drugs (AEDs) alone were systematically reviewed and quantified using fixed- or random-effects meta-analysis. Results: Fifteen RCTs were identified for inclusion. Ten RCTs assigned 765 people with SCG to AED treatment with or without anthelminthic drug (albendazole) treatment. A further 5 RCTs assigned 457 people with SCG to AED treatment with or without corticosteroid drugs. Anthelminthic treatment was associated with significantly increased rates of seizure freedom (nonevent odds ratio: 2.45; 95% confidence interval: 1.49–4.03; p = 0.0004) and significantly higher rates of granuloma resolution (odds ratio: 2.09; 95% confidence interval: 1.41–3.00; p = 0.0003), but did not alter the risk of residual calcification. Corticosteroid treatment was not significantly associated with any outcome. Conclusions: Anthelminthic treatment with albendazole provides improved rates of seizure freedom and hastens resolution of the granuloma. The role of corticosteroid treatment remains uncertain. The benefits (or lack thereof in the case of corticosteroids) are consistent when measured across different time points after treatment. PMID:23269591

A high-resolution mid-Pleistocene temperature record from Arctic Lake El'gygytgyn: a 50 kyr super interglacial from MIS 33 to MIS 31?

NASA Astrophysics Data System (ADS)

de Wet, Gregory A.; Castañeda, Isla S.; DeConto, Robert M.; Brigham-Grette, Julie

2016-02-01

Previous periods of extreme warmth in Earth's history are of great interest in light of current and predicted anthropogenic warming. Numerous so called "super interglacial" intervals, with summer temperatures significantly warmer than today, have been identified in the 3.6 million year (Ma) sediment record from Lake El'gygytgyn, northeast Russia. To date, however, a high-resolution paleotemperature reconstruction from any of these super interglacials is lacking. Here we present a paleotemperature reconstruction based on branched glycerol dialkyl glycerol tetraethers (brGDGTs) from Marine Isotope Stages (MIS) 35 to MIS 29, including super interglacial MIS 31. To investigate this period in detail, samples were analyzed with an unprecedented average sample resolution of 500 yrs from MIS 33 to MIS 30. Our results suggest the entire period currently defined as MIS 33-31 (∼1114-1062 kyr BP) was characterized by generally warm and highly variable conditions at the lake, at times out of phase with Northern Hemisphere summer insolation, and that cold "glacial" conditions during MIS 32 lasted only a few thousand years. Close similarities are seen with coeval records from high southern latitudes, supporting the suggestion that the interval from MIS 33 to MIS 31 was an exceptionally long interglacial (Teitler et al., 2015). Based on brGDGT temperatures from Lake El'gygytgyn (this study and unpublished results), warming in the western Arctic during MIS 31 was matched only by MIS 11 during the Pleistocene.

Near-real-time trace element measurements in a rural, traffic-influenced environment with some fireworks

NASA Astrophysics Data System (ADS)

Furger, Markus; Slowik, Jay G.; Cruz Minguillón, María; Hueglin, Christoph; Koch, Chris; Prévôt, André S. H.; Baltensperger, Urs

2016-04-01

Aerosol-bound trace elements can affect the environment in significant ways especially when they are toxic. Characterizing the trace element spatial and temporal variability is a prerequisite for human exposure studies. The requirement for high time resolution and consequently the low sample masses asked for analysis methods not easily accessible, such as synchrotron radiation-induced X-ray fluorescence spectrometry (SR-XRF). In recent years, instrumentation that samples and analyzes airborne particulate matter with time resolutions of less than an hour in near real time has entered the market. We present the results of a three-week campaign in a rural environment close to a freeway. The measurement period included the fireworks of the Swiss National Day. The XRF instrument was set up at the monitoring station Härkingen of the Swiss Monitoring Network for Air Pollution (NABEL). It was configured to sample and analyze ambient PM10 aerosols in 1-hour intervals. Sample analysis with XRF was performed by the instrument immediately after collection, i.e. during the next sampling interval. 24 elements were analyzed and quantified (Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Cd, Sn, Sb, Ba, Pt, Hg, Pb, Bi). The element concentrations obtained by the XRF instrument were compared to those determined by ICP-AES and ICP-MS in PM10 samples collected by NABEL high volume samplers. The results demonstrate the capability of the instrument to measure over a wide range of concentrations, from a few ng m-3 to μg m-3, under ambient conditions. The time resolution allows for the characterization of diurnal variations of element concentrations, which provides information on the contribution of emission sources, such as road traffic, soil, or fireworks. Some elements (V, Co, As, Pt) were below their detection limit during most of the time, but As could be quantified during the fireworks. Transition metals Cr, Mn, Fe, Cu, Zn could be attributed to freeway traffic. K, S, Ba, and Bi were strongly linked to the fireworks. The field test provided good evidence for the applicability and ease of use of the instrument. It provided also an idea on the sensitivity of the method in realistic, ambient conditions, although the 3-week period was too short for a thorough assessment, e.g. for different weather conditions.

Rainfall disaggregation for urban hydrology: Effects of spatial consistence

NASA Astrophysics Data System (ADS)

Müller, Hannes; Haberlandt, Uwe

2015-04-01

For urban hydrology rainfall time series with a high temporal resolution are crucial. Observed time series of this kind are very short in most cases, so they cannot be used. On the contrary, time series with lower temporal resolution (daily measurements) exist for much longer periods. The objective is to derive time series with a long duration and a high resolution by disaggregating time series of the non-recording stations with information of time series of the recording stations. The multiplicative random cascade model is a well-known disaggregation model for daily time series. For urban hydrology it is often assumed, that a day consists of only 1280 minutes in total as starting point for the disaggregation process. We introduce a new variant for the cascade model, which is functional without this assumption and also outperforms the existing approach regarding time series characteristics like wet and dry spell duration, average intensity, fraction of dry intervals and extreme value representation. However, in both approaches rainfall time series of different stations are disaggregated without consideration of surrounding stations. This yields in unrealistic spatial patterns of rainfall. We apply a simulated annealing algorithm that has been used successfully for hourly values before. Relative diurnal cycles of the disaggregated time series are resampled to reproduce the spatial dependence of rainfall. To describe spatial dependence we use bivariate characteristics like probability of occurrence, continuity ratio and coefficient of correlation. Investigation area is a sewage system in Northern Germany. We show that the algorithm has the capability to improve spatial dependence. The influence of the chosen disaggregation routine and the spatial dependence on overflow occurrences and volumes of the sewage system will be analyzed.

Nitrate flux on the Ross Ice Shelf, Antarctica and its relation to solar cosmic rays

NASA Astrophysics Data System (ADS)

Zeller, Edward J.; Dreschhoff, Gisela A. M.; Laird, Claude M.

1986-11-01

Nitrate flux has been determined in the snow sequence deposited at Windless Bight on the Ross Ice Shelf (Antarctica). The data were obtained from on-site analysis of nitrate concentrations from a glaciological pit and a firn core spanning the time interval from midwinter 1971 to January 1986. The high resolution data can be combined with precipitation records collected from adjacent areas to provide a record of nitrate flow. The resulting time series contains a signal which corresponds to the two major solar events of 1972 and 1984. The concentration and flux profiles may be useful in studies of Antarctic ozone depletion.

Net community production from autonomous oxygen observations in the Sargasso Sea

NASA Astrophysics Data System (ADS)

Feen, M.; Estapa, M. L.

2016-02-01

Optical sensors on autonomous floats provide high-resolution profiles of oxygen concentration over time. Improved spatiotemporal resolution in our measurements of oxygen will allow for better estimates of net community production and a greater understanding of the biological pump. Two autonomous profiling floats (NAVIS BGCi, Sea-Bird) equipped with SBE-63 optodes to measure dissolved oxygen were deployed in the Sargasso Sea on a series of five Bermuda Atlantic Time-series Study (BATS) cruises from July 2013 to April 2014. In situ calibration of the oxygen sensors to Winkler titration bottle samples at BATS did not show systematic drift in the oxygen sensors over time. Calibrations were applied to determine oxygen concentrations in profiles collected in the Sargasso Sea at 1.5 to 2.5 day intervals over a year. Oxygen concentrations were used to quantify sub-mixed layer net community production. Changes in production rates from this study were compared with upper water column biology and particle flux measurements obtained independently from optical sensors on the profiling floats, allowing us to examine processes controlling carbon export into the deep ocean.

Development of two-framing camera with large format and ultrahigh speed

NASA Astrophysics Data System (ADS)

Jiang, Xiaoguo; Wang, Yuan; Wang, Yi

2012-10-01

High-speed imaging facility is important and necessary for the formation of time-resolved measurement system with multi-framing capability. The framing camera which satisfies the demands of both high speed and large format needs to be specially developed in the ultrahigh speed research field. A two-framing camera system with high sensitivity and time-resolution has been developed and used for the diagnosis of electron beam parameters of Dragon-I linear induction accelerator (LIA). The camera system, which adopts the principle of light beam splitting in the image space behind the lens with long focus length, mainly consists of lens-coupled gated image intensifier, CCD camera and high-speed shutter trigger device based on the programmable integrated circuit. The fastest gating time is about 3 ns, and the interval time between the two frames can be adjusted discretely at the step of 0.5 ns. Both the gating time and the interval time can be tuned to the maximum value of about 1 s independently. Two images with the size of 1024×1024 for each can be captured simultaneously in our developed camera. Besides, this camera system possesses a good linearity, uniform spatial response and an equivalent background illumination as low as 5 electrons/pix/sec, which fully meets the measurement requirements of Dragon-I LIA.

Accelerometer Data Analysis and Presentation Techniques

NASA Technical Reports Server (NTRS)

Rogers, Melissa J. B.; Hrovat, Kenneth; McPherson, Kevin; Moskowitz, Milton E.; Reckart, Timothy

1997-01-01

The NASA Lewis Research Center's Principal Investigator Microgravity Services project analyzes Orbital Acceleration Research Experiment and Space Acceleration Measurement System data for principal investigators of microgravity experiments. Principal investigators need a thorough understanding of data analysis techniques so that they can request appropriate analyses to best interpret accelerometer data. Accelerometer data sampling and filtering is introduced along with the related topics of resolution and aliasing. Specific information about the Orbital Acceleration Research Experiment and Space Acceleration Measurement System data sampling and filtering is given. Time domain data analysis techniques are discussed and example environment interpretations are made using plots of acceleration versus time, interval average acceleration versus time, interval root-mean-square acceleration versus time, trimmean acceleration versus time, quasi-steady three dimensional histograms, and prediction of quasi-steady levels at different locations. An introduction to Fourier transform theory and windowing is provided along with specific analysis techniques and data interpretations. The frequency domain analyses discussed are power spectral density versus frequency, cumulative root-mean-square acceleration versus frequency, root-mean-square acceleration versus frequency, one-third octave band root-mean-square acceleration versus frequency, and power spectral density versus frequency versus time (spectrogram). Instructions for accessing NASA Lewis Research Center accelerometer data and related information using the internet are provided.

New method for obtaining position and time structure of source in HDR remote afterloading brachytherapy unit utilizing light emission from scintillator

PubMed Central

Hanada, Takashi; Katsuta, Shoichi; Yorozu, Atsunori; Maruyama, Koichi

2009-01-01

When using a HDR remote afterloading brachytherapy unit, results of treatment can be greatly influenced by both source position and treatment time. The purpose of this study is to obtain information on the source of the HDR remote afterloading unit, such as its position and time structure, with the use of a simple system consisting of a plastic scintillator block and a charge‐coupled device (CCD) camera. The CCD camera was used for recording images of scintillation luminescence at a fixed rate of 30 frames per second in real time. The source position and time structure were obtained by analyzing the recorded images. For a preset source‐step‐interval of 5 mm, the measured value of the source position was 5.0±1.0mm, with a pixel resolution of 0.07 mm in the recorded images. For a preset transit time of 30 s, the measured value was 30.0±0.6 s, when the time resolution of the CCD camera was 1/30 s. This system enabled us to obtain the source dwell time and movement time. Therefore, parameters such as I192r source position, transit time, dwell time, and movement time at each dwell position can be determined quantitatively using this plastic scintillator‐CCD camera system. PACS number: 87.53.Jw

High resolution power spectra of daily Zurich sunspot numbers

NASA Technical Reports Server (NTRS)

Euler, H. C., Jr.

1973-01-01

High resolution power spectra of 77 years of Zurich daily sunspot numbers were computed using various lags and data point intervals. Major harmonic peaks of the approximately 124-month period showed up strongly as well as the 27-day solar rotational period.

Increasing the temporal resolution of direct normal solar irradiance forecasted series

NASA Astrophysics Data System (ADS)

Fernández-Peruchena, Carlos M.; Gastón, Martin; Schroedter-Homscheidt, Marion; Marco, Isabel Martínez; Casado-Rubio, José L.; García-Moya, José Antonio

2017-06-01

A detailed knowledge of the solar resource is a critical point in the design and control of Concentrating Solar Power (CSP) plants. In particular, accurate forecasting of solar irradiance is essential for the efficient operation of solar thermal power plants, the management of energy markets, and the widespread implementation of this technology. Numerical weather prediction (NWP) models are commonly used for solar radiation forecasting. In the ECMWF deterministic forecasting system, all forecast parameters are commercially available worldwide at 3-hourly intervals. Unfortunately, as Direct Normal solar Irradiance (DNI) exhibits a great variability due to the dynamic effects of passing clouds, 3-h time resolution is insufficient for accurate simulations of CSP plants due to their nonlinear response to DNI, governed by various thermal inertias due to their complex response characteristics. DNI series of hourly or sub-hourly frequency resolution are normally used for an accurate modeling and analysis of transient processes in CSP technologies. In this context, the objective of this study is to propose a methodology for generating synthetic DNI time series at 1-h (or higher) temporal resolution from 3-h DNI series. The methodology is based upon patterns as being defined with help of the clear-sky envelope approach together with a forecast of maximum DNI value, and it has been validated with high quality measured DNI data.

Evolution of motion uncertainty in rectal cancer: implications for adaptive radiotherapy

NASA Astrophysics Data System (ADS)

Kleijnen, Jean-Paul J. E.; van Asselen, Bram; Burbach, Johannes P. M.; Intven, Martijn; Philippens, Marielle E. P.; Reerink, Onne; Lagendijk, Jan J. W.; Raaymakers, Bas W.

2016-01-01

Reduction of motion uncertainty by applying adaptive radiotherapy strategies depends largely on the temporal behavior of this motion. To fully optimize adaptive strategies, insight into target motion is needed. The purpose of this study was to analyze stability and evolution in time of motion uncertainty of both the gross tumor volume (GTV) and clinical target volume (CTV) for patients with rectal cancer. We scanned 16 patients daily during one week, on a 1.5 T MRI scanner in treatment position, prior to each radiotherapy fraction. Single slice sagittal cine MRIs were made at the beginning, middle, and end of each scan session, for one minute at 2 Hz temporal resolution. GTV and CTV motion were determined by registering a delineated reference frame to time-points later in time. The 95th percentile of observed motion (dist95%) was taken as a measure of motion. The stability of motion in time was evaluated within each cine-MRI separately. The evolution of motion was investigated between the reference frame and the cine-MRIs of a single scan session and between the reference frame and the cine-MRIs of several days later in the course of treatment. This observed motion was then converted into a PTV-margin estimate. Within a one minute cine-MRI scan, motion was found to be stable and small. Independent of the time-point within the scan session, the average dist95% remains below 3.6 mm and 2.3 mm for CTV and GTV, respectively 90% of the time. We found similar motion over time intervals from 18 min to 4 days. When reducing the time interval from 18 min to 1 min, a large reduction in motion uncertainty is observed. A reduction in motion uncertainty, and thus the PTV-margin estimate, of 71% and 75% for CTV and tumor was observed, respectively. Time intervals of 15 and 30 s yield no further reduction in motion uncertainty compared to a 1 min time interval.

Mediterranean Outflow Water at the Pliocene/Pleistocene transition: New stratigraphic constraints from IODP Site U1389 (Gulf of Cadiz, IODP Expedition 339)

NASA Astrophysics Data System (ADS)

Grunert, Patrick; Balestra, Barbara; Auer, Gerald; Flores, José-Abel; Richter, Carl; García Gallardo, Ángela; Röhl, Ulla; Piller, Werner E.

2016-04-01

IODP Hole U1389E, at present located in the lower core of the Mediterranean Outflow Water (MOW) at 640m water depth in the northern Gulf of Cadiz, represents a key-site for the understanding of changes in MOW contribution to the North Atlantic during the late Pliocene and the transition into the Pleistocene ice house climate. Integrated geophysical, micropalaeontological and geochemical proxy records of the recovered sediments imply major changes in MOW strength over the studied interval. However, to consider these data in a broader paleoceanographic and paleoclimatic context, a well-constrained age model is essential. New bio-, chemo-, magnetostratigraphic data and XRF core-scanning suggest that the shipboard age model for the site has to be reconsidered as major changes in the depositional environment have not been recognized in the original, comparably low resolution data-sets. While the new, high-resolution biostratigraphic data confirm the overall time frame of 2.6 to 3.6 Myrs for the studied interval, they also indicate that the last occurrence of Discoaster tamalis in the succession should be reconsidered. New palaeomagnetic data constrain the Gauss normal chron and its subchrons more accurately. Finally, a high-resolution δ18O-record of the planktic foraminifer Globigerinoides ruber allows the identification of many marine isotopic chrons, further refining the stratigraphic framework. Cyclic patterns are recognized in the CaCO3 and TOC contents as well as Ca/Ti- and Zr/Al-ratios. A preliminary cyclostratigraphic analysis of these records in well-recovered intervals suggests an interplay of obliquity and precessional forcing reflected in a change from deposits strongly influenced by terrestrial input (3.0-2.8 Myrs) to deposits strongly affected by MOW (2.8-2.6 Myrs). This study contributes to project P25831-N29 of the Austrian Science Fund (FWF) and is financially supported by grants of ECORD and the Max Kade Foundation.

An Extension of the Time-Spectral Method to Overset Solvers

NASA Technical Reports Server (NTRS)

Leffell, Joshua Isaac; Murman, Scott M.; Pulliam, Thomas

2013-01-01

Relative motion in the Cartesian or overset framework causes certain spatial nodes to move in and out of the physical domain as they are dynamically blanked by moving solid bodies. This poses a problem for the conventional Time-Spectral approach, which expands the solution at every spatial node into a Fourier series spanning the period of motion. The proposed extension to the Time-Spectral method treats unblanked nodes in the conventional manner but expands the solution at dynamically blanked nodes in a basis of barycentric rational polynomials spanning partitions of contiguously defined temporal intervals. Rational polynomials avoid Runge's phenomenon on the equidistant time samples of these sub-periodic intervals. Fourier- and rational polynomial-based differentiation operators are used in tandem to provide a consistent hybrid Time-Spectral overset scheme capable of handling relative motion. The hybrid scheme is tested with a linear model problem and implemented within NASA's OVERFLOW Reynolds-averaged Navier- Stokes (RANS) solver. The hybrid Time-Spectral solver is then applied to inviscid and turbulent RANS cases of plunging and pitching airfoils and compared to time-accurate and experimental data. A limiter was applied in the turbulent case to avoid undershoots in the undamped turbulent eddy viscosity while maintaining accuracy. The hybrid scheme matches the performance of the conventional Time-Spectral method and converges to the time-accurate results with increased temporal resolution.

Study of the Effect of Temporal Sampling Frequency on DSCOVR Observations Using the GEOS-5 Nature Run Results. Part II; Cloud Coverage

NASA Technical Reports Server (NTRS)

Holdaway, Daniel; Yang, Yuekui

2016-01-01

This is the second part of a study on how temporal sampling frequency affects satellite retrievals in support of the Deep Space Climate Observatory (DSCOVR) mission. Continuing from Part 1, which looked at Earth's radiation budget, this paper presents the effect of sampling frequency on DSCOVR-derived cloud fraction. The output from NASA's Goddard Earth Observing System version 5 (GEOS-5) Nature Run is used as the "truth". The effect of temporal resolution on potential DSCOVR observations is assessed by subsampling the full Nature Run data. A set of metrics, including uncertainty and absolute error in the subsampled time series, correlation between the original and the subsamples, and Fourier analysis have been used for this study. Results show that, for a given sampling frequency, the uncertainties in the annual mean cloud fraction of the sunlit half of the Earth are larger over land than over ocean. Analysis of correlation coefficients between the subsamples and the original time series demonstrates that even though sampling at certain longer time intervals may not increase the uncertainty in the mean, the subsampled time series is further and further away from the "truth" as the sampling interval becomes larger and larger. Fourier analysis shows that the simulated DSCOVR cloud fraction has underlying periodical features at certain time intervals, such as 8, 12, and 24 h. If the data is subsampled at these frequencies, the uncertainties in the mean cloud fraction are higher. These results provide helpful insights for the DSCOVR temporal sampling strategy.

A Nonlinearity Minimization-Oriented Resource-Saving Time-to-Digital Converter Implemented in a 28 nm Xilinx FPGA

NASA Astrophysics Data System (ADS)

Wang, Yonggang; Liu, Chong

2015-10-01

Because large nonlinearity errors exist in the current tapped-delay line (TDL) style field programmable gate array (FPGA)-based time-to-digital converters (TDC), bin-by-bin calibration techniques have to be resorted for gaining a high measurement resolution. If the TDL in selected FPGAs is significantly affected by changes in ambient temperature, the bin-by-bin calibration table has to be updated as frequently as possible. The on-line calibration and calibration table updating increase the TDC design complexity and limit the system performance to some extent. This paper proposes a method to minimize the nonlinearity errors of TDC bins, so that the bin-by-bin calibration may not be needed while maintaining a reasonably high time resolution. The method is a two pass approach: By a bin realignment, the large number of wasted zero-width bins in the original TDL is reused and the granularity of the bins is improved; by a bin decimation, the bin size and its uniformity is traded-off, and the time interpolation by the delay line turns more precise so that the bin-by-bin calibration is not necessary. Using Xilinx 28 nm FPGAs, in which the TDL property is not very sensitive to ambient temperature, the proposed TDC achieves approximately 15 ps root-mean-square (RMS) time resolution by dual-channel measurements of time-intervals over the range of operating temperature. Because of removing the calibration and less logic resources required for the data post-processing, the method has bigger multi-channel capability.

A confidence interval analysis of sampling effort, sequencing depth, and taxonomic resolution of fungal community ecology in the era of high-throughput sequencing.

PubMed

Oono, Ryoko

2017-01-01

High-throughput sequencing technology has helped microbial community ecologists explore ecological and evolutionary patterns at unprecedented scales. The benefits of a large sample size still typically outweigh that of greater sequencing depths per sample for accurate estimations of ecological inferences. However, excluding or not sequencing rare taxa may mislead the answers to the questions 'how and why are communities different?' This study evaluates the confidence intervals of ecological inferences from high-throughput sequencing data of foliar fungal endophytes as case studies through a range of sampling efforts, sequencing depths, and taxonomic resolutions to understand how technical and analytical practices may affect our interpretations. Increasing sampling size reliably decreased confidence intervals across multiple community comparisons. However, the effects of sequencing depths on confidence intervals depended on how rare taxa influenced the dissimilarity estimates among communities and did not significantly decrease confidence intervals for all community comparisons. A comparison of simulated communities under random drift suggests that sequencing depths are important in estimating dissimilarities between microbial communities under neutral selective processes. Confidence interval analyses reveal important biases as well as biological trends in microbial community studies that otherwise may be ignored when communities are only compared for statistically significant differences.

A confidence interval analysis of sampling effort, sequencing depth, and taxonomic resolution of fungal community ecology in the era of high-throughput sequencing

PubMed Central

2017-01-01

High-throughput sequencing technology has helped microbial community ecologists explore ecological and evolutionary patterns at unprecedented scales. The benefits of a large sample size still typically outweigh that of greater sequencing depths per sample for accurate estimations of ecological inferences. However, excluding or not sequencing rare taxa may mislead the answers to the questions ‘how and why are communities different?’ This study evaluates the confidence intervals of ecological inferences from high-throughput sequencing data of foliar fungal endophytes as case studies through a range of sampling efforts, sequencing depths, and taxonomic resolutions to understand how technical and analytical practices may affect our interpretations. Increasing sampling size reliably decreased confidence intervals across multiple community comparisons. However, the effects of sequencing depths on confidence intervals depended on how rare taxa influenced the dissimilarity estimates among communities and did not significantly decrease confidence intervals for all community comparisons. A comparison of simulated communities under random drift suggests that sequencing depths are important in estimating dissimilarities between microbial communities under neutral selective processes. Confidence interval analyses reveal important biases as well as biological trends in microbial community studies that otherwise may be ignored when communities are only compared for statistically significant differences. PMID:29253889

A stretch/compress scheme for a high temporal resolution detector for the magnetic recoil spectrometer time (MRSt)

DOE PAGES

Hilsabeck, T. J.; Frenje, J. A.; Hares, J. D.; ...

2016-08-02

Here we present a time-resolved detector concept for the magnetic recoil spectrometer for time-resolved measurements of the NIF neutron spectrum. The measurement is challenging due to the time spreading of the recoil protons (or deuterons) as they transit an energy dispersing magnet system. Ions arrive at the focal plane of the magnetic spectrometer over an interval of tens of nanoseconds. We seek to measure the time-resolved neutron spectrum with 20 ps precision by manipulating an electron signal derived from the ions. A stretch-compress scheme is employed to remove transit time skewing while simultaneously reducing the bandwidth requirements for signal recording.more » Simulation results are presented along with design concepts for structures capable of establishing the required electromagnetic fields.« less

A stretch/compress scheme for a high temporal resolution detector for the magnetic recoil spectrometer time (MRSt)

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

Hilsabeck, T. J.; Frenje, J. A.; Hares, J. D.

Here we present a time-resolved detector concept for the magnetic recoil spectrometer for time-resolved measurements of the NIF neutron spectrum. The measurement is challenging due to the time spreading of the recoil protons (or deuterons) as they transit an energy dispersing magnet system. Ions arrive at the focal plane of the magnetic spectrometer over an interval of tens of nanoseconds. We seek to measure the time-resolved neutron spectrum with 20 ps precision by manipulating an electron signal derived from the ions. A stretch-compress scheme is employed to remove transit time skewing while simultaneously reducing the bandwidth requirements for signal recording.more » Simulation results are presented along with design concepts for structures capable of establishing the required electromagnetic fields.« less

Lightning electromagnetic radiation field spectra in the interval from 0.2 to 20 MHz

NASA Technical Reports Server (NTRS)

Willett, J. C.; Bailey, J. C.; Leteinturier, C.; Krider, E. P.

1990-01-01

New Fourier transforms of wideband time-domain electric fields (E) produced by lightning (recorded at the Kennedy Space Center during the summers of 1985 and 1987) were recorded in such a way that several different events in each lightning flash could be captured. Average HF spectral amplitudes for first return strokes, stepped-leader steps, and 'characteristic pulses' are given for significantly more events, at closer ranges, and with better spectral resolution than in previous literature reports. The method of recording gives less bias toward the first large event in the flash and thus yields a large sample of a wide variety of lightning processes. As a result, reliable composite spectral amplitudes are obtained for a number of different processes in cloud-to-ground lightning over the frequency interval from 0.2 to 20 MHz.

Age accuracy and resolution of Quaternary corals used as proxies for sea level

NASA Astrophysics Data System (ADS)

Edinger, E. N.; Burr, G. S.; Pandolfi, J. M.; Ortiz, J. C.

2007-01-01

The accuracy of global eustatic sea level curves measured from raised Quaternary reefs, using radiometric ages of corals at known heights, may be limited by time-averaging, which affects the variation in coral age at a given height. Time-averaging was assessed in uplifted Holocene reef sequences from the Huon Peninsula, Papua New Guinea, using radiocarbon dating of coral skeletons in both horizontal transects and vertical sequences. Calibrated 2σ age ranges varied from 800 to 1060 years along horizontal transects, but weighted mean ages calculated from 15-18 dates per horizon were accurate to a resolution within 154-214 yr. Approximately 40% of the variability in age estimate resulted from internal variability inherent to 14C estimates, and 60% was due to time-averaging. The accuracy of age estimates of sea level change in studies using single dated corals as proxies for sea level is probably within 1000 yr of actual age, but can be resolved to ≤ 250 yr if supported by dates from analysis of a statistical population of corals at each stratigraphic interval. The range of time-averaging among reef corals was much less than that for shelly benthos. Ecological time-averaging dominated over sedimentological time averaging for reef corals, opposite to patterns reported from shelly benthos in siliciclastic environments.

A High-Resolution Record of Holocene Climate Variability from a Western Canadian Coastal Inlet

NASA Astrophysics Data System (ADS)

Dallimore, A.; Thomson, R. E.; Enkin, R. J.; Kulikov, E. A.; Bertram, M. A.; Wright, C. A.; Southon, J. R.; Barrie, J. V.; Baker, J.; Pienitz, R.; Calvert, S. E.; Chang, A. S.; Pedersen, T. F.

2004-12-01

Conditions within the Pacific Ocean have a major effect on the climate of northwestern North America. High resolution records of present and past northeast Pacific climate are revealed in our multi-disciplinary study of annually laminated marine sediments from anoxic coastal inlets of British Columbia. Past climate conditions for the entire Holocene are recorded in the sediment record contained in a 40 meter, annually laminated marine sediment core taken in Effingham Inlet, on the west coast of Vancouver Island, British Columbia, from the French ship the Marion Dufresne, as part of the international IMAGES program. By combining our eight year continuous instrument record of modern coastal ocean dynamics and climate with high-resolution analysis of depositional processes, we have been able to develop proxy measurements of past climatic and oceanographic changes on annual to millennial time scales. Results indicate that regional climate has oscillated on a variety of time scales throughout the Holocene. At times, climatic change has been dramatically rapid. We are also developing digital methods for statistical time-series analyses of physical sediment properties through the Holocene in order to obtain a more objective quantitative approach for detecting cyclicity in our data. Results of the time series analysis of lamination thickness reveals statistically significant spectral peaks of climate scale variability at established decadal to century time scales. These in turn may be related to solar cycles and quasi-cyclical ocean processes such as the Pacific Decadal Oscillation. However, the annually laminated time series are periodically interrupted by massive mud intervals which are related to bottom currents and at times paleo-seismic events, illustrating the need for a full understanding of modern oceanographic and sedimentation processes, so an accurate proxy record of past climate can be established.

A new stochastic model considering satellite clock interpolation errors in precise point positioning

NASA Astrophysics Data System (ADS)

Wang, Shengli; Yang, Fanlin; Gao, Wang; Yan, Lizi; Ge, Yulong

2018-03-01

Precise clock products are typically interpolated based on the sampling interval of the observational data when they are used for in precise point positioning. However, due to the occurrence of white noise in atomic clocks, a residual component of such noise will inevitable reside within the observations when clock errors are interpolated, and such noise will affect the resolution of the positioning results. In this paper, which is based on a twenty-one-week analysis of the atomic clock noise characteristics of numerous satellites, a new stochastic observation model that considers satellite clock interpolation errors is proposed. First, the systematic error of each satellite in the IGR clock product was extracted using a wavelet de-noising method to obtain the empirical characteristics of atomic clock noise within each clock product. Then, based on those empirical characteristics, a stochastic observation model was structured that considered the satellite clock interpolation errors. Subsequently, the IGR and IGS clock products at different time intervals were used for experimental validation. A verification using 179 stations worldwide from the IGS showed that, compared with the conventional model, the convergence times using the stochastic model proposed in this study were respectively shortened by 4.8% and 4.0% when the IGR and IGS 300-s-interval clock products were used and by 19.1% and 19.4% when the 900-s-interval clock products were used. Furthermore, the disturbances during the initial phase of the calculation were also effectively improved.

Temporal slip-rate stability and variations on the Hope Fault, New Zealand, during the late Quaternary

NASA Astrophysics Data System (ADS)

Khajavi, Narges; Nicol, Andrew; Quigley, Mark C.; Langridge, Robert M.

2018-07-01

The Hope Fault transfers slip from Hikurangi subduction to the Alpine Fault in the northern South Island of New Zealand. It accommodates mainly dextral strike slip and currently carries the highest slip rate in the Marlborough Fault System. Displacements, displacement rates and earthquake recurrence intervals have been determined using a combination of high resolution LiDAR for 59 dextral displacements ( 2.5-200 m) together with calibrated radiocarbon ages ( 130 yr to 13,000 yr) for abandoned stream channels, terrace risers and alluvial fans. Mean single-event displacement (SED) of 3 ± 0.6 m (2.2 to 4.6 m for 21 measurements) and mean recurrence interval of 266 ± 100 yr (range 128 to 560 yr) have been determined for the five most recent surface-rupturing earthquakes. On time scales ≥2300 yr the dextral slip rate is uniform at 12.2 ± 2.4 mm/yr, however, when averaged over time intervals of 230 to 1700 yr slip rates range from 4 to 46.4 mm/yr. This order-of-magnitude variability in slip rate over shorter timescales cannot be fully attributed to errors in displacement and age data, and is at least partly due to variations in earthquake recurrence interval and inferred SED. Short-term non-characteristic earthquake behaviour may be due to changes in fault loading arising from stress interactions between different segments of the Hope Fault and nearby faults.

In vivo Proton Electron Double Resonance Imaging of Mice with Fast Spin Echo Pulse Sequence

PubMed Central

Sun, Ziqi; Li, Haihong; Petryakov, Sergey; Samouilov, Alex; Zweier, Jay L.

2011-01-01

Purpose To develop and evaluate a 2D fast spin echo (FSE) pulse sequence for enhancing temporal resolution and reducing tissue heating for in vivo proton electron double resonance imaging (PEDRI) of mice. Materials and Methods A four-compartment phantom containing 2 mM TEMPONE was imaged at 20.1 mT using 2D FSE-PEDRI and regular gradient echo (GRE)-PEDRI pulse sequences. Control mice were infused with TEMPONE over ∼1 min followed by time-course imaging using the 2D FSE-PEDRI sequence at intervals of 10 – 30 s between image acquisitions. The average signal intensity from the time-course images was analyzed using a first-order kinetics model. Results Phantom experiments demonstrated that EPR power deposition can be greatly reduced using the FSE-PEDRI pulse sequence compared to the conventional gradient echo pulse sequence. High temporal resolution was achieved at ∼4 s per image acquisition using the FSE-PEDRI sequence with a good image SNR in the range of 233-266 in the phantom study. The TEMPONE half-life measured in vivo was ∼72 s. Conclusion Thus, the FSE-PEDRI pulse sequence enables fast in vivo functional imaging of free radical probes in small animals greatly reducing EPR irradiation time with decreased power deposition and provides increased temporal resolution. PMID:22147559

Myocardial perfusion magnetic resonance imaging using sliding-window conjugate-gradient highly constrained back-projection reconstruction for detection of coronary artery disease.

PubMed

Ma, Heng; Yang, Jun; Liu, Jing; Ge, Lan; An, Jing; Tang, Qing; Li, Han; Zhang, Yu; Chen, David; Wang, Yong; Liu, Jiabin; Liang, Zhigang; Lin, Kai; Jin, Lixin; Bi, Xiaoming; Li, Kuncheng; Li, Debiao

2012-04-15

Myocardial perfusion magnetic resonance imaging (MRI) with sliding-window conjugate-gradient highly constrained back-projection reconstruction (SW-CG-HYPR) allows whole left ventricular coverage, improved temporal and spatial resolution and signal/noise ratio, and reduced cardiac motion-related image artifacts. The accuracy of this technique for detecting coronary artery disease (CAD) has not been determined in a large number of patients. We prospectively evaluated the diagnostic performance of myocardial perfusion MRI with SW-CG-HYPR in patients with suspected CAD. A total of 50 consecutive patients who were scheduled for coronary angiography with suspected CAD underwent myocardial perfusion MRI with SW-CG-HYPR at 3.0 T. The perfusion defects were interpreted qualitatively by 2 blinded observers and were correlated with x-ray angiographic stenoses ≥50%. The prevalence of CAD was 56%. In the per-patient analysis, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of SW-CG-HYPR was 96% (95% confidence interval 82% to 100%), 82% (95% confidence interval 60% to 95%), 87% (95% confidence interval 70% to 96%), 95% (95% confidence interval 74% to100%), and 90% (95% confidence interval 82% to 98%), respectively. In the per-vessel analysis, the corresponding values were 98% (95% confidence interval 91% to 100%), 89% (95% confidence interval 80% to 94%), 86% (95% confidence interval 76% to 93%), 99% (95% confidence interval 93% to 100%), and 93% (95% confidence interval 89% to 97%), respectively. In conclusion, myocardial perfusion MRI using SW-CG-HYPR allows whole left ventricular coverage and high resolution and has high diagnostic accuracy in patients with suspected CAD. Copyright © 2012 Elsevier Inc. All rights reserved.

Relationship between heart rate and quiescent interval of the cardiac cycle in children using MRI.

PubMed

Zhang, Wei; Bogale, Saivivek; Golriz, Farahnaz; Krishnamurthy, Rajesh

2017-11-01

Imaging the heart in children comes with the challenge of constant cardiac motion. A prospective electrocardiography-triggered CT scan allows for scanning during a predetermined phase of the cardiac cycle with least motion. This technique requires knowing the optimal quiescent intervals of cardiac cycles in a pediatric population. To evaluate high-temporal-resolution cine MRI of the heart in children to determine the relationship of heart rate to the optimal quiescent interval within the cardiac cycle. We included a total of 225 consecutive patients ages 0-18 years who had high-temporal-resolution cine steady-state free-precession sequence performed as part of a magnetic resonance imaging (MRI) or magnetic resonance angiography study of the heart. We determined the location and duration of the quiescent interval in systole and diastole for heart rates ranging 40-178 beats per minute (bpm). We performed the Wilcoxon signed rank test to compare the duration of quiescent interval in systole and diastole for each heart rate group. The duration of the quiescent interval at heart rates <80 bpm and >90 bpm was significantly longer in diastole and systole, respectively (P<.0001 for all ranges, except for 90-99 bpm [P=.02]). For heart rates 80-89 bpm, diastolic interval was longer than systolic interval, but the difference was not statistically significant (P=.06). We created a chart depicting optimal quiescent intervals across a range of heart rates that could be applied for prospective electrocardiography-triggered CT imaging of the heart. The optimal quiescent interval at heart rates <80 bpm is in diastole and at heart rates ≥90 bpm is in systole. The period of quiescence at heart rates 80-89 bpm is uniformly short in systole and diastole.

Generation and Validation of Spatial Distribution of Hourly Wind Speed Time-Series using Machine Learning

NASA Astrophysics Data System (ADS)

Veronesi, F.; Grassi, S.

2016-09-01

Wind resource assessment is a key aspect of wind farm planning since it allows to estimate the long term electricity production. Moreover, wind speed time-series at high resolution are helpful to estimate the temporal changes of the electricity generation and indispensable to design stand-alone systems, which are affected by the mismatch of supply and demand. In this work, we present a new generalized statistical methodology to generate the spatial distribution of wind speed time-series, using Switzerland as a case study. This research is based upon a machine learning model and demonstrates that statistical wind resource assessment can successfully be used for estimating wind speed time-series. In fact, this method is able to obtain reliable wind speed estimates and propagate all the sources of uncertainty (from the measurements to the mapping process) in an efficient way, i.e. minimizing computational time and load. This allows not only an accurate estimation, but the creation of precise confidence intervals to map the stochasticity of the wind resource for a particular site. The validation shows that machine learning can minimize the bias of the wind speed hourly estimates. Moreover, for each mapped location this method delivers not only the mean wind speed, but also its confidence interval, which are crucial data for planners.

Intercalibration of radioisotopic and astrochronologic time scales for the Cenomanian-Turonian boundary interval, western interior Basin, USA

USGS Publications Warehouse

Meyers, S.R.; Siewert, S.E.; Singer, B.S.; Sageman, B.B.; Condon, D.J.; Obradovich, J.D.; Jicha, B.R.; Sawyer, D.A.

2012-01-01

We develop an intercalibrated astrochronologic and radioisotopic time scale for the Cenomanian-Turonian boundary (CTB) interval near the Global Stratotype Section and Point in Colorado, USA, where orbitally influenced rhythmic strata host bentonites that contain sanidine and zircon suitable for 40Ar/ 39Ar and U-Pb dating. Paired 40Ar/ 39Ar and U-Pb ages are determined from four bentonites that span the Vascoceras diartianum to Pseudaspidoceras flexuosum ammonite biozones, utilizing both newly collected material and legacy sanidine samples of J. Obradovich. Comparison of the 40Ar/ 39Ar and U-Pb results underscores the strengths and limitations of each system, and supports an astronomically calibrated Fish Canyon sanidine standard age of 28.201 Ma. The radioisotopic data and published astrochronology are employed to develop a new CTB time scale, using two statistical approaches: (1) a simple integration that yields a CTB age of 93.89 ?? 0.14 Ma (2??; total radioisotopic uncertainty), and (2) a Bayesian intercalibration that explicitly accounts for orbital time scale uncertainty, and yields a CTB age of 93.90 ?? 0.15 Ma (95% credible interval; total radioisotopic and orbital time scale uncertainty). Both approaches firmly anchor the floating orbital time scale, and the Bayesian technique yields astronomically recalibrated radioisotopic ages for individual bentonites, with analytical uncertainties at the permil level of resolution, and total uncertainties below 2???. Using our new results, the duration between the Cenomanian-Turonian and the Cretaceous-Paleogene boundaries is 27.94 ?? 0.16 Ma, with an uncertainty of less than one-half of a long eccentricity cycle. ?? 2012 Geological Society of America.

The effects of time compositing on obtaining clear-sky coverage for infrared temperature and moisture profiling from geosynchronous orbit

NASA Technical Reports Server (NTRS)

Shenk, William E.; Hope, William A.

1994-01-01

The impact of time compositing on infrared profiling from geosynchronous orbit was evaluated for two convective outbreak cases. Time compositing is the accumulation of the data from several successive images taken at short intervals to provide a single field of measurements with the temporal resolution equal to the time to take all of the images. This is especially effective when the variability of the measurements is slow compared to the image interval. Time compositing should be able to reduce the interference of clouds for infrared measurments since clouds move and change. The convective outbreak cases were on 4 and 21 May 1990 over the eastern Midwest and southeastern United States, respectively. Geostationary Operational Environmental (GOES) Satellite imagery was used to outline clear areas at hourly intervals by two independent analysts. Time compositing was done every 3 h (1330-1530 UTC; 1630-1830 UTC) and over the full 5-h period. For both cases, a significant increase in coverage was measured with each 3-h compositing (about a factor of 2) and a further increase over the full period (approximately a factor of 3). The increase was especially useful in areas of broken cloud cover where large gaps between potential profiling areas on each image were reduced. To provide information on measurement variability over local areas, the regions where the clear-area analyses were done were subdivided into 0.5 deg latitude-longitude boxes, and if some portion of each box was clear, it was assumed that at least one profile could be obtained within the box. In the largest clear areas, at least some portion was clear every hour. Even in the cloudier regions, multiple clear looks possible during the entire period.

Continuous methane measurements from a late Holocene Greenland ice core: Atmospheric and in-situ signals

NASA Astrophysics Data System (ADS)

Rhodes, Rachael H.; Faïn, Xavier; Stowasser, Christopher; Blunier, Thomas; Chappellaz, Jérôme; McConnell, Joseph R.; Romanini, Daniele; Mitchell, Logan E.; Brook, Edward J.

2013-04-01

Ancient air trapped inside bubbles in ice cores can now be analysed for methane concentration utilising a laser spectrometer coupled to a continuous melter system. We present a new ultra-high resolution record of atmospheric methane variability over the last 1800 yr obtained from continuous analysis of a shallow ice core from the North Greenland Eemian project (NEEM-2011-S1) during a 4-week laboratory-based measurement campaign. Our record faithfully replicates the form and amplitudes of multi-decadal oscillations previously observed in other ice cores and demonstrates the detailed depth resolution (5.3 cm), rapid acquisition time (30 m day-1) and good long-term reproducibility (2.6%, 2σ) of the continuous measurement technique. In addition, we report the detection of high frequency ice core methane signals of non-atmospheric origin. Firstly, measurements of air from the firn-ice transition region and an interval of ice core dating from 1546-1560 AD (gas age) resolve apparently quasi-annual scale methane oscillations. Traditional gas chromatography measurements on discrete ice samples confirm these signals and indicate peak-to-peak amplitudes of ca. 22 parts per billion (ppb). We hypothesise that these oscillations result from staggered bubble close-off between seasonal layers of contrasting density during time periods of sustained multi-year atmospheric methane change. Secondly, we report the detection of abrupt (20-100 cm depth interval), high amplitude (35-80 ppb excess) methane spikes in the NEEM ice that are reproduced by discrete measurements. We show for the first time that methane spikes present in thin and infrequent layers in polar, glacial ice are accompanied by elevated concentrations of carbon- and nitrogen-based chemical impurities, and suggest that biological in-situ production may be responsible.

Magnetic resonance imaging is more sensitive than radiographs in detecting change in size of erosions in rheumatoid arthritis.

PubMed

Chen, Timothy S; Crues, John V; Ali, Muhammad; Troum, Orrin M

2006-10-01

To evaluate the technological performance of magnetic resonance imaging (MRI) with respect to projection radiography by determining the incidence of changes in the size of individual bone lesions in inflammatory arthritis, using serial high-resolution in-office MRI over short time intervals (8 months average followup), and by comparing the sensitivity of 3-view projection radiography with in-office MRI for detecting changes in size and number of individual erosions. MR examinations of the wrists and second and third metacarpophalangeal joints were performed using a portable in-office MR system in a total of 405 patients with inflammatory arthritis, from one rheumatologist's practice, who were undergoing aggressive disease modifying antirheumatic drug therapy. Of the patients, 156 were imaged at least twice, allowing evaluation of 246 followup examinations (mean followup interval of 8 months over a 2-year period). Baseline and followup plain radiographs were obtained in 165 patient intervals. Patients refused radiographic examination on 81 followup visits. MRI demonstrated no detectable changes in 124 of the 246 (50%) followup MRI examinations. An increase in the size or number of erosions was demonstrated in 74 (30%) examinations, a decrease in the size or number of erosions in 36 (15%), and both increases and decreases in erosions were seen in 11 (4%). In the 165 studies with followup radiographic comparisons, only one examination (0.8%) showed an erosion not seen on the prior examination and one (0.8%) showed an increase in a previously noted erosion. We showed that high-resolution in-office MRI with an average followup of 8 months detects changes in bony disease in 50% of compliant patients during aggressive treatment for inflammatory arthritis in a single rheumatologist's office practice. Plain radiography is insensitive for detecting changes in bone erosions for this patient population in this time frame.

Multi-component time, spatial and frequency analysis of Paleoclimatic Data

NASA Astrophysics Data System (ADS)

Cristiano, Luigia; Stampa, Johannes; Feeser, Ingo; Dörfler, Walter; Meier, Thomas

2017-04-01

The investigation of the paleoclimatic data offers a powerful tool for understanding the impact of extreme climatic events as well as gradual climatic variations on the human development and cultural changes. The current global record of paleoclimatic data is relatively rich but is not generally uniformly structured and regionally distributed. The general characteristic of the reconstructed time series of paleoclimatic data is a not constant sampling interval and data resolution together with the presence of gaps in the record. Our database consists of pollen concentration from annually laminated lake sediments in two sites in Northern Germany. Such data characteristic offers the possibility for high-resolution palynological and sedimentological analyses on a well constrained time scale. Specifically we are interested to investigate the time dependence of proxies, and time and spatial correlation of the different observables respect each other. We present here a quantitative analysis of the pollent data in the frequency and time. In particular we are interested to understand the complexity of the system and understand the cause of sudden as well as the slow changes in the time dependence of the observables. We show as well our approach for handling the not uniform sampling interval and the broad frequency content characterizing the paleoclimatic databases. In particular we worked to the development of a robust data analysis to answer the key questions about the correlation between rapid climatic changes and changes in the human habits and quantitatively elaborate a model for the processed data. Here we present the preliminary results on synthetics as well as on real data for the data visualization for the trend identification with a smoothing procedure, for the identification of sharp changes in the data as function of time with AutoRegressive approach. In addition to that we use the cross-correlation and cross spectrum by applying the Multiple Filtering Technique(MFT) of different pollen data from same location and same pollen data from different locations to identify the short and long period terms and to quantify the similarities in time and frequency domain.

Estimating the free gas content in Baltic Sea sediments using compressional wave velocity from marine seismic data

NASA Astrophysics Data System (ADS)

Tóth, Zsuzsanna; Spiess, Volkhard; Mogollón, José M.; Jensen, Jørn Bo

2014-12-01

A 2-D high-resolution velocity field was obtained from marine seismic data to quantify free gas content in shallow muddy sediments at in situ pressure and temperature. The velocities were acquired applying Migration Velocity Analysis on prestack time-migrated data. Compressional wave velocities are highly sensitive to free gas as very small amounts of gas can cause a significant decrease in the medium velocity. The analyzed profile crosses a depression filled with organic-rich Holocene mud in the Bornholm Basin, Baltic Sea. The interval velocity field reveals two low-velocity patches, which extend from the reversed polarity reflections marking the top of the gassy sediment layer down to the base of the Holocene mud. Average interval velocities within the gassy mud are lower than the seafloor migration velocity by up to ˜500 m/s. This decrease, using a geoacoustic model, is caused by an average 0.046% gas volume fraction. The interval velocities in individual cells of the velocity field are reduced to ˜200 m/s predicting up to 3.4% gas content. The velocity field is limited in resolution due to velocity determination at and between reflections; however, together with the stratigraphic interpretation, geological units containing free gas could be identified. Shallow gas occurs vertically throughout most of the Holocene mud in the gassy area. Comparison with biogeochemical studies at other Baltic Sea sites suggests that the distribution of free gas is likely to be patchy in the sediment, but the gas concentration may peak below the sulfate-methane transition zone and gradually decrease below.

Observations of fine scale structure in the mesosphere and lower thermosphere

NASA Astrophysics Data System (ADS)

Thrane, E. V.; Grandal, B.

1980-06-01

An electrostatic probe designed to measure ion density with high time resolution and accuracy was flown on a Nike-Apache rocket from Andoeya Rocket Range on March 1 1978. Spectra of the spatial density fluctuations were derived in one kilometer height intervals from 65 to 127 km. Below 95 km the power spectra had a slope of about -5/3, as expected for isotropic turbulence. Above 95 km the fluctuations were stronger and showed a white noise power spectrum. These fluctuations are most likely due to plasma instabilities.

Anatomy of Some Non-Heinrich Events During The Last Glacial Maximum on Laurentian Fan

NASA Astrophysics Data System (ADS)

Gil, I. M.; Keigwin, L. D.

2013-12-01

High-resolution diatom assemblage analyses coupled with oxygen and carbon isotopic records from a new 28 m piston core on Laurentian Fan reveal significant sedimentological and marine productivity changes related to variability of the nearby Laurentide Ice Sheet during the Last Glacial Maximum. Between 21.0 and 19.7 ka and between 18.8 and 18.6 ka, olive-grey clays intervals interrupt the usual glacial red-clays sedimentation. The timing of these two intervals corresponds to reported occurrence of layers low in detrital carbonate (LDC, considered as non-Heinrich events) that occurred between Heinrich Event 1 and 2. Diatoms are only abundant during those LDC - olive-grey clay intervals and suggest ice retreat (allowing light penetration necessary to diatoms). The species succession reveals also different environmental conditions. The 21.0 to 19.7 ka interval is divisible to two main periods: the first was characterized by environmental conditions dominated by ice, while the second period (starting at 20.2 ka) was warmer than the first. During the shorter 18.8 to 18.6 ka interval, conditions were even warmer than during the 20.2 to 19.7 ka sub-interval. Finally, the comparison of the interpreted oceanographic conditions with changes in Ice Rafted Debris and other records from the North Atlantic will bring a new insight into those episodes that precede the transition to deglaciation beginning ~18.2 ka on Laurentian Fan (based on δ18-O in N. pachyderma (s.)).

A Behavioral Economic Reward Index Predicts Drinking Resolutions: Moderation Re-visited and Compared with Other Outcomes

PubMed Central

Tucker, Jalie A.; Roth, David L.; Vignolo, Mary J.; Westfall, Andrew O.

2014-01-01

Data were pooled from three studies of recently resolved community-dwelling problem drinkers to determine whether a behavioral economic index of the value of rewards available over different time horizons distinguished among moderation (n = 30), abstinent (n = 95), and unresolved (n = 77) outcomes. Moderation over 1-2 year prospective follow-up intervals was hypothesized to involve longer term behavior regulation processes compared to abstinence or relapse and to be predicted by more balanced pre-resolution monetary allocations between short- and longer-term objectives (i.e., drinking and saving for the future). Standardized odds ratios (OR) based on changes in standard deviation units from a multinomial logistic regression indicated that increases on this “Alcohol-Savings Discretionary Expenditure” index predicted higher rates of both abstinence (OR = 1.93, p = .004) and relapse (OR = 2.89, p < .0001) compared to moderation outcomes. The index had incremental utility in predicting moderation in complex models that included other established predictors. The study adds to evidence supporting a behavioral economic analysis of drinking resolutions and shows that a systematic analysis of pre-resolution spending patterns aids in predicting moderation. PMID:19309182

A Sub-ps Stability Time Transfer Method Based on Optical Modems.

PubMed

Frank, Florian; Stefani, Fabio; Tuckey, Philip; Pottie, Paul-Eric

2018-06-01

Coherent optical fiber links recently demonstrate their ability to compare the most advanced optical clocks over a continental scale. The outstanding performances of the optical clocks are stimulating the community to build much more stable time scales, and to develop the means to compare them. Optical fiber link is one solution that needs to be explored. Here, we are investigating a new method to transfer time based on an optical demodulation of a phase step imprint onto the optical carrier. We show the implementation of a proof-of-principle experiment over 86-km urban fiber, and report time interval transfer stability of 1 pulse per second signal with sub-ps resolution from 10 s to one day of measurement time. Prospects for future development and implementation in active telecommunication networks, not only regarding performance but also compatibility, conclude this paper.

A multiscale Bayesian data integration approach for mapping air dose rates around the Fukushima Daiichi Nuclear Power Plant.

PubMed

Wainwright, Haruko M; Seki, Akiyuki; Chen, Jinsong; Saito, Kimiaki

2017-02-01

This paper presents a multiscale data integration method to estimate the spatial distribution of air dose rates in the regional scale around the Fukushima Daiichi Nuclear Power Plant. We integrate various types of datasets, such as ground-based walk and car surveys, and airborne surveys, all of which have different scales, resolutions, spatial coverage, and accuracy. This method is based on geostatistics to represent spatial heterogeneous structures, and also on Bayesian hierarchical models to integrate multiscale, multi-type datasets in a consistent manner. The Bayesian method allows us to quantify the uncertainty in the estimates, and to provide the confidence intervals that are critical for robust decision-making. Although this approach is primarily data-driven, it has great flexibility to include mechanistic models for representing radiation transport or other complex correlations. We demonstrate our approach using three types of datasets collected at the same time over Fukushima City in Japan: (1) coarse-resolution airborne surveys covering the entire area, (2) car surveys along major roads, and (3) walk surveys in multiple neighborhoods. Results show that the method can successfully integrate three types of datasets and create an integrated map (including the confidence intervals) of air dose rates over the domain in high resolution. Moreover, this study provides us with various insights into the characteristics of each dataset, as well as radiocaesium distribution. In particular, the urban areas show high heterogeneity in the contaminant distribution due to human activities as well as large discrepancy among different surveys due to such heterogeneity. Copyright © 2016 Elsevier Ltd. All rights reserved.

High-Resolution Paleomagnetic Observations from Ocean Drilling: Insights from Coring Thick Sediment Drift Deposits

NASA Astrophysics Data System (ADS)

Acton, G. D.; Clement, B. M.; Lund, S. P.; Okada, M.; Williams, T.

2003-04-01

With the advent of the Hydraulic Piston Corer at the end of the Deep Sea Drilling Program and its enhanced successor, the Advanced Piston Corer (APC), developed by the Ocean Drilling Program (ODP), coring through thick (>100 m), rapidly deposited sequences of unconsolidated to partially consolidated sediments with near 100% recovery has become common place. Although much of the emphasis for site selection has been based on paleoceanographic objectives, the impact to the field of paleomagnetism has been dramatic, both in the instruments used to analyze the large quantity of core recovered and in the questions that can be answered concerning geomagnetic field behavior and paleoenvironmental conditions. The largest change has come in the construction of relative paleointensity records, which have provided previously unimagined details about how the geomagnetic field varies in strength during stable polarity intervals as well as during reversals and excursions. These records have allowed more realistic models of the geomagnetic field to be developed while also providing a new chronologic tool for high-resolution dating and global correlation of geomagnetic events. Studies of how the paleomagnetic direction varies through time have not advanced as rapidly and have instead mainly been focused on short time intervals across a few geomagnetic reversals. It should, however, be possible to construct and compare secular variation records with millennial or better resolution that span the past one million years from sites around the world as correlation and chronologies between sites improve. We will give an overview that focuses on secular variation records that are being constructed from sediment drifts drilled in the western North Atlantic during ODP Leg 172. Our results will be used to address questions concerning what percent of time the geomagnetic field is in a stable state versus transitional or excursional states, what the relationship is between directional variability and relative paleointensity, which secular variation features are global and which are local, what is the origin of local directional changes, and how climate and rock magnetic changes influence the paleomagnetic signal.

High-resolution Atmospheric pCO2 Reconstruction across the Paleogene Using Marine and Terrestrial δ13C records

NASA Astrophysics Data System (ADS)

Cui, Y.; Schubert, B.

2016-02-01

The early Paleogene (63 to 47 Ma) is considered to have a greenhouse climate1 with proxies suggesting atmospheric CO2 levels (pCO2) approximately 2× pre-industrial levels. However, the proxy based pCO2 reconstructions are limited and do not allow for assessment of changes in pCO2 at million to sub-million year time scales. It has recently been recognized that changes in C3 land plant carbon isotope fractionation can be used as a proxy for pCO2 with quantifiable uncertainty2. Here, we present a high-resolution pCO2 reconstruction (n = 597) across the early Paleogene using published carbon isotope data from both terrestrial organic matter and marine carbonates. The minimum and maximum pCO2 values reconstructed using this method are broad (i.e., 170 +60/-40 ppmv to 2000 +4480/-1060 ppmv) and reflective of the wide range of environments sampled. However, the large number of measurements allows for a robust estimate of average pCO2 during this time interval ( 400 +260/-120 ppmv), and indicates brief (sub-million-year) excursions to very high pCO2 during hyperthermal events (e.g., the PETM). By binning our high-resolution pCO2 data at 1 million year intervals, we can compare our dataset to the other available pCO2 proxies. Our result is broadly consistent with pCO2 levels reconstructed using other proxies, with the exception of paleosol-based pCO2 estimates spanning 53 to 50 Ma. At this timescale, no proxy suggests pCO2 higher than 2000 ppmv, whereas the global surface ocean temperature is considered to be >10 oC warmer than today. Recent climate modeling suggests that low atmospheric pressure during this time period could help reconcile the apparent disconnect between pCO2 and temperature and contribute to the greenhouse climate3. References1. Huber, M., Caballero, R., 2011. Climate of the Past 7, 603-633. 2. Schubert, B.A., Jahren, A.H., 2015. Geology 43, 435-438. 3. Poulsen, C.J., Tabor, C., White, J.D., 2015. Science 348, 1238-1241.

Pre- versus post-mass extinction divergence of Mesozoic marine reptiles dictated by time-scale dependence of evolutionary rates.

PubMed

Motani, Ryosuke; Jiang, Da-Yong; Tintori, Andrea; Ji, Cheng; Huang, Jian-Dong

2017-05-17

The fossil record of a major clade often starts after a mass extinction even though evolutionary rates, molecular or morphological, suggest its pre-extinction emergence (e.g. squamates, placentals and teleosts). The discrepancy is larger for older clades, and the presence of a time-scale-dependent methodological bias has been suggested, yet it has been difficult to avoid the bias using Bayesian phylogenetic methods. This paradox raises the question of whether ecological vacancies, such as those after mass extinctions, prompt the radiations. We addressed this problem by using a unique temporal characteristic of the morphological data and a high-resolution stratigraphic record, for the oldest clade of Mesozoic marine reptiles, Ichthyosauromorpha. The evolutionary rate was fastest during the first few million years of ichthyosauromorph evolution and became progressively slower over time, eventually becoming six times slower. Using the later slower rates, estimates of divergence time become excessively older. The fast, initial rate suggests the emergence of ichthyosauromorphs after the end-Permian mass extinction, matching an independent result from high-resolution stratigraphic confidence intervals. These reptiles probably invaded the sea as a new ecosystem was formed after the end-Permian mass extinction. Lack of information on early evolution biased Bayesian clock rates. © 2017 The Author(s).

Pre- versus post-mass extinction divergence of Mesozoic marine reptiles dictated by time-scale dependence of evolutionary rates

PubMed Central

Ji, Cheng; Huang, Jian-dong

2017-01-01

The fossil record of a major clade often starts after a mass extinction even though evolutionary rates, molecular or morphological, suggest its pre-extinction emergence (e.g. squamates, placentals and teleosts). The discrepancy is larger for older clades, and the presence of a time-scale-dependent methodological bias has been suggested, yet it has been difficult to avoid the bias using Bayesian phylogenetic methods. This paradox raises the question of whether ecological vacancies, such as those after mass extinctions, prompt the radiations. We addressed this problem by using a unique temporal characteristic of the morphological data and a high-resolution stratigraphic record, for the oldest clade of Mesozoic marine reptiles, Ichthyosauromorpha. The evolutionary rate was fastest during the first few million years of ichthyosauromorph evolution and became progressively slower over time, eventually becoming six times slower. Using the later slower rates, estimates of divergence time become excessively older. The fast, initial rate suggests the emergence of ichthyosauromorphs after the end-Permian mass extinction, matching an independent result from high-resolution stratigraphic confidence intervals. These reptiles probably invaded the sea as a new ecosystem was formed after the end-Permian mass extinction. Lack of information on early evolution biased Bayesian clock rates. PMID:28515201

Harmful algal bloom characterization at ultra-high spatial and temporal resolution using small unmanned aircraft systems.

PubMed

Van der Merwe, Deon; Price, Kevin P

2015-03-27

Harmful algal blooms (HABs) degrade water quality and produce toxins. The spatial distribution of HAbs may change rapidly due to variations wind, water currents, and population dynamics. Risk assessments, based on traditional sampling methods, are hampered by the sparseness of water sample data points, and delays between sampling and the availability of results. There is a need for local risk assessment and risk management at the spatial and temporal resolution relevant to local human and animal interactions at specific sites and times. Small, unmanned aircraft systems can gather color-infrared reflectance data at appropriate spatial and temporal resolutions, with full control over data collection timing, and short intervals between data gathering and result availability. Data can be interpreted qualitatively, or by generating a blue normalized difference vegetation index (BNDVI) that is correlated with cyanobacterial biomass densities at the water surface, as estimated using a buoyant packed cell volume (BPCV). Correlations between BNDVI and BPCV follow a logarithmic model, with r(2)-values under field conditions from 0.77 to 0.87. These methods provide valuable information that is complimentary to risk assessment data derived from traditional risk assessment methods, and could help to improve risk management at the local level.

Japan unified hIgh-resolution relocated catalog for earthquakes (JUICE): Crustal seismicity beneath the Japanese Islands

NASA Astrophysics Data System (ADS)

Yano, Tomoko E.; Takeda, Tetsuya; Matsubara, Makoto; Shiomi, Katsuhiko

2017-04-01

We have generated a high-resolution catalog called the ;Japan Unified hIgh-resolution relocated Catalog for Earthquakes; (JUICE), which can be used to evaluate the geometry and seismogenic depth of active faults in Japan. We relocated > 1.1 million hypocenters from the NIED Hi-net catalog for events which occurred between January 2001 and December 2012, to a depth of 40 km. We apply a relative hypocenter determination method to the data in each grid square, in which entire Japan is divided into 1257 grid squares to parallelize the relocation procedure. We used a double-difference method, incorporating cross-correlating differential times as well as catalog differential times. This allows us to resolve, in detail, a seismicity distribution for the entire Japanese Islands. We estimated location uncertainty by a statistical resampling method, using Jackknife samples, and show that the uncertainty can be within 0.37 km in the horizontal and 0.85 km in the vertical direction with a 90% confidence interval for areas with good station coverage. Our seismogenic depth estimate agrees with the lower limit of the hypocenter distribution for a recent earthquake on the Kamishiro fault (2014, Mj 6.7), which suggests that the new catalog should be useful for estimating the size of future earthquakes for inland active faults.

Study of the Effect of Temporal Sampling Frequency on DSCOVR Observations Using the GEOS-5 Nature Run Results (Part I): Earths Radiation Budget

NASA Technical Reports Server (NTRS)

Holdaway, Daniel; Yang, Yuekui

2016-01-01

Satellites always sample the Earth-atmosphere system in a finite temporal resolution. This study investigates the effect of sampling frequency on the satellite-derived Earth radiation budget, with the Deep Space Climate Observatory (DSCOVR) as an example. The output from NASA's Goddard Earth Observing System Version 5 (GEOS-5) Nature Run is used as the truth. The Nature Run is a high spatial and temporal resolution atmospheric simulation spanning a two-year period. The effect of temporal resolution on potential DSCOVR observations is assessed by sampling the full Nature Run data with 1-h to 24-h frequencies. The uncertainty associated with a given sampling frequency is measured by computing means over daily, monthly, seasonal and annual intervals and determining the spread across different possible starting points. The skill with which a particular sampling frequency captures the structure of the full time series is measured using correlations and normalized errors. Results show that higher sampling frequency gives more information and less uncertainty in the derived radiation budget. A sampling frequency coarser than every 4 h results in significant error. Correlations between true and sampled time series also decrease more rapidly for a sampling frequency less than 4 h.

A high-resolution peak fractionation approach for streamlined screening of nuclear-factor-E2-related factor-2 activators in Salvia miltiorrhiza.

PubMed

Zhang, Hui; Luo, Li-Ping; Song, Hui-Peng; Hao, Hai-Ping; Zhou, Ping; Qi, Lian-Wen; Li, Ping; Chen, Jun

2014-01-24

Generation of a high-purity fraction library for efficiently screening active compounds from natural products is challenging because of their chemical diversity and complex matrices. In this work, a strategy combining high-resolution peak fractionation (HRPF) with a cell-based assay was proposed for target screening of bioactive constituents from natural products. In this approach, peak fractionation was conducted under chromatographic conditions optimized for high-resolution separation of the natural product extract. The HRPF approach was automatically performed according to the predefinition of certain peaks based on their retention times from a reference chromatographic profile. The corresponding HRPF database was collected with a parallel mass spectrometer to ensure purity and characterize the structures of compounds in the various fractions. Using this approach, a set of 75 peak fractions on the microgram scale was generated from 4mg of the extract of Salvia miltiorrhiza. After screening by an ARE-luciferase reporter gene assay, 20 diterpene quinones were selected and identified, and 16 of these compounds were reported to possess novel Nrf2 activation activity. Compared with conventional fixed-time interval fractionation, the HRPF approach could significantly improve the efficiency of bioactive compound discovery and facilitate the uncovering of minor active components. Copyright © 2013 Elsevier B.V. All rights reserved.

Harmful Algal Bloom Characterization at Ultra-High Spatial and Temporal Resolution Using Small Unmanned Aircraft Systems

PubMed Central

Van der Merwe, Deon; Price, Kevin P.

2015-01-01

Harmful algal blooms (HABs) degrade water quality and produce toxins. The spatial distribution of HAbs may change rapidly due to variations wind, water currents, and population dynamics. Risk assessments, based on traditional sampling methods, are hampered by the sparseness of water sample data points, and delays between sampling and the availability of results. There is a need for local risk assessment and risk management at the spatial and temporal resolution relevant to local human and animal interactions at specific sites and times. Small, unmanned aircraft systems can gather color-infrared reflectance data at appropriate spatial and temporal resolutions, with full control over data collection timing, and short intervals between data gathering and result availability. Data can be interpreted qualitatively, or by generating a blue normalized difference vegetation index (BNDVI) that is correlated with cyanobacterial biomass densities at the water surface, as estimated using a buoyant packed cell volume (BPCV). Correlations between BNDVI and BPCV follow a logarithmic model, with r2-values under field conditions from 0.77 to 0.87. These methods provide valuable information that is complimentary to risk assessment data derived from traditional risk assessment methods, and could help to improve risk management at the local level. PMID:25826055

Test of a single module of the J-PET scanner based on plastic scintillators

NASA Astrophysics Data System (ADS)

Moskal, P.; Niedźwiecki, Sz.; Bednarski, T.; Czerwiński, E.; Kapłon, Ł.; Kubicz, E.; Moskal, I.; Pawlik-Niedźwiecka, M.; Sharma, N. G.; Silarski, M.; Zieliński, M.; Zoń, N.; Białas, P.; Gajos, A.; Kochanowski, A.; Korcyl, G.; Kowal, J.; Kowalski, P.; Kozik, T.; Krzemień, W.; Molenda, M.; Pałka, M.; Raczyński, L.; Rudy, Z.; Salabura, P.; Słomski, A.; Smyrski, J.; Strzelecki, A.; Wieczorek, A.; Wiślicki, W.

2014-11-01

A Time of Flight Positron Emission Tomography scanner based on plastic scintillators is being developed at the Jagiellonian University by the J-PET collaboration. The main challenge of the conducted research lies in the elaboration of a method allowing application of plastic scintillators for the detection of low energy gamma quanta. In this paper we report on tests of a single detection module built out from the BC-420 plastic scintillator strip (with dimensions of 5×19×300 mm3) read out at two ends by Hamamatsu R5320 photomultipliers. The measurements were performed using collimated beam of annihilation quanta from the 68Ge isotope and applying the Serial Data Analyzer (Lecroy SDA6000A) which enabled sampling of signals with 50 ps intervals. The time resolution of the prototype module was established to be better than 80 ps (σ) for a single level discrimination. The spatial resolution of the determination of the hit position along the strip was determined to be about 0.93 cm (σ) for the annihilation quanta. The fractional energy resolution for the energy E deposited by the annihilation quanta via the Compton scattering amounts to σ(E) / E ≈ 0.044 /√{ E(MeV) } and corresponds to the σ(E) / E of 7.5% at the Compton edge.

Overview of geostationary ocean color imager (GOCI) and GOCI data processing system (GDPS)

NASA Astrophysics Data System (ADS)

Ryu, Joo-Hyung; Han, Hee-Jeong; Cho, Seongick; Park, Young-Je; Ahn, Yu-Hwan

2012-09-01

GOCI, the world's first geostationary ocean color satellite, provides images with a spatial resolution of 500 m at hourly intervals up to 8 times a day, allowing observations of short-term changes in the Northeast Asian region. The GOCI Data Processing System (GDPS), a specialized data processing software for GOCI, was developed for real-time generation of various products. This paper describes GOCI characteristics and GDPS workflow/products, so as to enable the efficient utilization of GOCI. To provide quality images and data, atmospheric correction and data analysis algorithms must be improved through continuous Cal/Val. GOCI-II will be developed by 2018 to facilitate in-depth studies on geostationary ocean color satellites.

Using Four Downscaling Techniques to Characterize Uncertainty in Updating Intensity-Duration-Frequency Curves Under Climate Change

NASA Astrophysics Data System (ADS)

Cook, L. M.; Samaras, C.; McGinnis, S. A.

2017-12-01

Intensity-duration-frequency (IDF) curves are a common input to urban drainage design, and are used to represent extreme rainfall in a region. As rainfall patterns shift into a non-stationary regime as a result of climate change, these curves will need to be updated with future projections of extreme precipitation. Many regions have begun to update these curves to reflect the trends from downscaled climate models; however, few studies have compared the methods for doing so, as well as the uncertainty that results from the selection of the native grid scale and temporal resolution of the climate model. This study examines the variability in updated IDF curves for Pittsburgh using four different methods for adjusting gridded regional climate model (RCM) outputs into station scale precipitation extremes: (1) a simple change factor applied to observed return levels, (2) a naïve adjustment of stationary and non-stationary Generalized Extreme Value (GEV) distribution parameters, (3) a transfer function of the GEV parameters from the annual maximum series, and (4) kernel density distribution mapping bias correction of the RCM time series. Return level estimates (rainfall intensities) and confidence intervals from these methods for the 1-hour to 48-hour duration are tested for sensitivity to the underlying spatial and temporal resolution of the climate ensemble from the NA-CORDEX project, as well as, the future time period for updating. The first goal is to determine if uncertainty is highest for: (i) the downscaling method, (ii) the climate model resolution, (iii) the climate model simulation, (iv) the GEV parameters, or (v) the future time period examined. Initial results of the 6-hour, 10-year return level adjusted with the simple change factor method using four climate model simulations of two different spatial resolutions show that uncertainty is highest in the estimation of the GEV parameters. The second goal is to determine if complex downscaling methods and high-resolution climate models are necessary for updating, or if simpler methods and lower resolution climate models will suffice. The final results can be used to inform the most appropriate method and climate model resolutions to use for updating IDF curves for urban drainage design.

Patient navigation for breast and colorectal cancer in 3 community hospital settings: an economic evaluation.

PubMed

Donaldson, Elisabeth A; Holtgrave, David R; Duffin, Renea A; Feltner, Frances; Funderburk, William; Freeman, Harold P

2012-10-01

The Ralph Lauren Cancer Center implemented patient navigation programs in sites across the United States building on the model pioneered by Harold P. Freeman, MD. Patient navigation targets medically underserved with the objective of reducing the time interval between an abnormal cancer finding, diagnostic resolution, and treatment initiation. In this study, the authors assessed the incremental cost effectiveness of adding patient navigation to standard cancer care in 3 community hospitals in the United States. A decision-analytic model was used to assess the cost effectiveness of a colorectal and breast cancer patient navigation program over the period of 1 year compared with standard care. Data sources included published estimates in the literature and primary costs, aggregate patient demographics, and outcome data from 3 patient navigation programs. After 1 year, compared with standard care alone, it was estimated that offering patient navigation with standard care would allow an additional 78 of 959 individuals with an abnormal breast cancer screening and an additional 21 of 411 individuals with abnormal colonoscopies to reach timely diagnostic resolution. Without including medical treatment costs saved, the cost-effectiveness ratio ranged from $511 to $2080 per breast cancer diagnostic resolution achieved and from $1192 to $9708 per colorectal cancer diagnostic resolution achieved. The current results indicated that implementing breast or colorectal cancer patient navigation in community hospital settings in which low-income populations are served may be a cost-effective addition to standard cancer care in the United States. Copyright © 2012 American Cancer Society.

Energetic Particle Sounding of the Magnetopause Deformed by Hot Flow Anomaly

NASA Astrophysics Data System (ADS)

Zhao, L.; Zong, Q.; Zhang, H.

2017-12-01

Hot flow anomalies (HFAs), which are frequently observed near Earth's bow shock, are phenomena resulting from the interaction between interplanetary discontinuities and Earth's bow shock. Such transient phenomena upstream the bow shock can cause significant deformation of the bow shock and the magnetosphere, generating traveling convection vortices, field-aligned currents, and ULF waves in the Earth's magnetosphere. A large HFA was observed by MMS on November 19, 2015, lasting about 16 minutes. In this study, energetic particle sounding method with high time resolution (150 ms) Fast Plasma Investigation (FPI) data is used to determine the deformed magnetopause distances, orientations, and structures in the interval when MMS pass through the deformed magnetopause. The energetic particle sounding result from single MMS satellite for every moment in the interval when the distance from the magnetopause to the satellite is less than two proton gyro radii shows the profile of the deformed magnetopause.

WE-G-BRD-08: Motion Analysis for Rectal Cancer: Implications for Adaptive Radiotherapy On the MR-Linac

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

Kleijnen, J; Asselen, B van; Burbach, M

2015-06-15

Purpose: Purpose of this study is to find the optimal trade-off between adaptation interval and margin reduction and to define the implications of motion for rectal cancer boost radiotherapy on a MR-linac. Methods: Daily MRI scans were acquired of 16 patients, diagnosed with rectal cancer, prior to each radiotherapy fraction in one week (N=76). Each scan session consisted of T2-weighted and three 2D sagittal cine-MRI, at begin (t=0 min), middle (t=9:30 min) and end (t=18:00 min) of scan session, for 1 minute at 2 Hz temporal resolution. Tumor and clinical target volume (CTV) were delineated on each T2-weighted scan andmore » transferred to each cine-MRI. The start frame of the begin scan was used as reference and registered to frames at time-points 15, 30 and 60 seconds, 9:30 and 18:00 minutes and 1, 2, 3 and 4 days later. Per time-point, motion of delineated voxels was evaluated using the deformation vector fields of the registrations and the 95th percentile distance (dist95%) was calculated as measure of motion. Per time-point, the distance that includes 90% of all cases was taken as estimate of required planning target volume (PTV)-margin. Results: Highest motion reduction is observed going from 9:30 minutes to 60 seconds. We observe a reduction in margin estimates from 10.6 to 2.7 mm and 16.1 to 4.6 mm for tumor and CTV, respectively, when adapting every 60 seconds compared to not adapting treatment. A 75% and 71% reduction, respectively. Further reduction in adaptation time-interval yields only marginal motion reduction. For adaptation intervals longer than 18:00 minutes only small motion reductions are observed. Conclusion: The optimal adaptation interval for adaptive rectal cancer (boost) treatments on a MR-linac is 60 seconds. This results in substantial smaller PTV-margin estimates. Adaptation intervals of 18:00 minutes and higher, show little improvement in motion reduction.« less

Cost-effectiveness of Skin Cancer Referral and Consultation Using Teledermoscopy in Australia.

PubMed

Snoswell, Centaine L; Caffery, Liam J; Whitty, Jennifer A; Soyer, H Peter; Gordon, Louisa G

2018-06-01

International literature has shown that teledermoscopy referral may be a viable method for skin cancer referral; however, no economic investigations have occurred in Australia. To assess the cost-effectiveness of teledermoscopy as a referral mechanism for skin cancer diagnosis and management in Australia. Cost-effectiveness analysis using a decision-analytic model of Australian primary care, informed by publicly available data. We compared the costs of teledermoscopy referral (electronic referral containing digital dermoscopic images) vs usual care (a written referral letter) for specialist dermatologist review of a suspected skin cancer. Cost and time in days to clinical resolution, where clinical resolution was defined as diagnosis by a dermatologist or excision by a general practitioner. Probabilistic sensitivity analysis was performed to examine the uncertainty of the main results. Findings from the decision-analytic model showed that the mean time to clinical resolution was 9 days (range, 1-50 days) with teledermoscopy referral compared with 35 days (range, 0-138 days) with usual care alone (difference, 26 days; 95% credible interval [CrI], 13-38 days). The estimated mean cost difference between teledermoscopy referral (A$318.39) vs usual care (A$263.75) was A$54.64 (95% CrI, A$22.69-A$97.35) per person. The incremental cost per day saved to clinical resolution was A$2.10 (95% CrI, A$0.87-A$5.29). Using teledermoscopy for skin cancer referral and triage in Australia would cost A$54.64 extra per case on average but would result in clinical resolution 26 days sooner than usual care. Implementation recommendations depend on the preferences of the Australian health system decision makers for either lower cost or expedited clinical resolution. Further research around the clinical significance of expedited clinical resolution and its importance for patients could inform implementation recommendations for the Australian setting.

Enhancing the Selection of Backoff Interval Using Fuzzy Logic over Wireless Ad Hoc Networks

PubMed Central

Ranganathan, Radha; Kannan, Kathiravan

2015-01-01

IEEE 802.11 is the de facto standard for medium access over wireless ad hoc network. The collision avoidance mechanism (i.e., random binary exponential backoff—BEB) of IEEE 802.11 DCF (distributed coordination function) is inefficient and unfair especially under heavy load. In the literature, many algorithms have been proposed to tune the contention window (CW) size. However, these algorithms make every node select its backoff interval between [0, CW] in a random and uniform manner. This randomness is incorporated to avoid collisions among the nodes. But this random backoff interval can change the optimal order and frequency of channel access among competing nodes which results in unfairness and increased delay. In this paper, we propose an algorithm that schedules the medium access in a fair and effective manner. This algorithm enhances IEEE 802.11 DCF with additional level of contention resolution that prioritizes the contending nodes according to its queue length and waiting time. Each node computes its unique backoff interval using fuzzy logic based on the input parameters collected from contending nodes through overhearing. We evaluate our algorithm against IEEE 802.11, GDCF (gentle distributed coordination function) protocols using ns-2.35 simulator and show that our algorithm achieves good performance. PMID:25879066

Megavolt parallel potentials arising from double-layer streams in the Earth's outer radiation belt.

PubMed

Mozer, F S; Bale, S D; Bonnell, J W; Chaston, C C; Roth, I; Wygant, J

2013-12-06

Huge numbers of double layers carrying electric fields parallel to the local magnetic field line have been observed on the Van Allen probes in connection with in situ relativistic electron acceleration in the Earth's outer radiation belt. For one case with adequate high time resolution data, 7000 double layers were observed in an interval of 1 min to produce a 230,000 V net parallel potential drop crossing the spacecraft. Lower resolution data show that this event lasted for 6 min and that more than 1,000,000 volts of net parallel potential crossed the spacecraft during this time. A double layer traverses the length of a magnetic field line in about 15 s and the orbital motion of the spacecraft perpendicular to the magnetic field was about 700 km during this 6 min interval. Thus, the instantaneous parallel potential along a single magnetic field line was the order of tens of kilovolts. Electrons on the field line might experience many such potential steps in their lifetimes to accelerate them to energies where they serve as the seed population for relativistic acceleration by coherent, large amplitude whistler mode waves. Because the double-layer speed of 3100  km/s is the order of the electron acoustic speed (and not the ion acoustic speed) of a 25 eV plasma, the double layers may result from a new electron acoustic mode. Acceleration mechanisms involving double layers may also be important in planetary radiation belts such as Jupiter, Saturn, Uranus, and Neptune, in the solar corona during flares, and in astrophysical objects.

Using high spectral resolution spectrophotometry to study broad mineral absorption features on Mars

NASA Technical Reports Server (NTRS)

Blaney, D. L.; Crisp, D.

1993-01-01

Traditionally telescopic measurements of mineralogic absorption features have been made using relatively low to moderate (R=30-300) spectral resolution. Mineralogic absorption features tend to be broad so high resolution spectroscopy (R greater than 10,000) does not provide significant additional compositional information. Low to moderate resolution spectroscopy allows an observer to obtain data over a wide wavelength range (hundreds to thousands of wavenumbers) compared to the several wavenumber intervals that are collected using high resolution spectrometers. However, spectrophotometry at high resolution has major advantages over lower resolution spectroscopy in situations that are applicable to studies of the Martian surface, i.e., at wavelengths where relatively weak surface absorption features and atmospheric gas absorption features both occur.

Metronome LKM: An open source virtual keyboard driver to measure experiment software latencies.

PubMed

Garaizar, Pablo; Vadillo, Miguel A

2017-10-01

Experiment software is often used to measure reaction times gathered with keyboards or other input devices. In previous studies, the accuracy and precision of time stamps has been assessed through several means: (a) generating accurate square wave signals from an external device connected to the parallel port of the computer running the experiment software, (b) triggering the typematic repeat feature of some keyboards to get an evenly separated series of keypress events, or (c) using a solenoid handled by a microcontroller to press the input device (keyboard, mouse button, touch screen) that will be used in the experimental setup. Despite the advantages of these approaches in some contexts, none of them can isolate the measurement error caused by the experiment software itself. Metronome LKM provides a virtual keyboard to assess an experiment's software. Using this open source driver, researchers can generate keypress events using high-resolution timers and compare the time stamps collected by the experiment software with those gathered by Metronome LKM (with nanosecond resolution). Our software is highly configurable (in terms of keys pressed, intervals, SysRq activation) and runs on 2.6-4.8 Linux kernels.

[Localizating and Extracting Small Peripheral Nodules of Lung with Simulating 
Radiaotherapy Combining Methylene Blue Staining].

PubMed

Mao, Feng; Zhang, Liang; Gu, Hengle; Zhang, Hui; Lv, Changxing; Shen-Tu, Yang

2016-09-20

With the extensively application of HRCT (high resolution CT) and the popularization of early lung cancer screening, the proportion of small nodullar lung cancer to be operated increases rapidly. Identifying the focus lesions quickly and accurately in operation has shown to be a challenge. We carried out this research trying to make use of and evaluate a new method that localizaes and extracts small peripheral pulmonary nodules by way of simulating radiaotherapy combining methylene blue staining. From February 2012 to January 2015, 97 patients with 100 peripheral pulmonary nodules ≤10 mm in size were simulated puncturing using a radiotherapy planning. When the anaesthesia came into use, methylene blue dye was injected to the virtually identified point corresponding to the surface point, according to the angle and depth previously computed by the radiotherapy planning. The video-assisted thoracoscopic surgery (VATS) wedge resections of the marked lesions were undertaken and the specimens were sent for frozen pathologic examination. The interval time from anesthesia-completing to puncture and injection, The interval time from methylene blue injection to identifying the stained area and the distances between the centre point of the stains and edge of coloured lesion were recorded. Our preoperative localization procedure was successful in 96 of 100 (96%) nodules. The interval time from anesthesia-completing to puncture and injection of methylene blue were (4.85±1.25) min. The interval time from methylene blue injection to identifying the stained area was (16.36±2.36) min. The distances between the centre point of the stains and edge of coloured lesion were (4.78±2.51) mm. No complication was observed in all participants. The new method of locating peripheral pulmonary nodules by simulating simulating radiaotherapy combining methylene blue staining has a high success rate and no complication for localizing small peripheral pulmonary lesions, avoiding the fear and pain of the patients untaken puncture without anaesthesia reducing radial damage.

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

Kishimoto, S., E-mail: syunji.kishimoto@kek.jp; Haruki, R.; Mitsui, T.

We developed a silicon avalanche photodiode (Si-APD) linear-array detector to be used for time-resolved X-ray scattering experiments using synchrotron X-rays. The Si-APD linear array consists of 64 pixels (pixel size: 100 × 200 μm{sup 2}) with a pixel pitch of 150 μm and a depletion depth of 10 μm. The multichannel scaler counted X-ray pulses over continuous 2046 time bins for every 0.5 ns and recorded a time spectrum at each pixel with a time resolution of 0.5 ns (FWHM) for 8.0 keV X-rays. Using the detector system, we were able to observe X-ray peaks clearly separated with 2 nsmore » interval in the multibunch-mode operation of the Photon Factory ring. The small-angle X-ray scattering for polyvinylidene fluoride film was also observed with the detector.« less

High-resolution stratigraphic analyses of Permian-Triassic core material recovered in central Spitsbergen

NASA Astrophysics Data System (ADS)

Sleveland, Arve; Planke, Sverre; Zuchuat, Valentin; Franeck, Franziska; Svensen, Henrik; Midtkandal, Ivar; Hammer, Øyvind; Twitchett, Richard; Deltadalen Study Group

2017-04-01

The Siberian Traps voluminous igneous activity is considered a likely trigger for the Permian-Triassic global extinction event. However, documented evidence of the Siberian Traps environmental effects decreases away from the centre of volcanic activity in north-central Russia. Previous research on the Permian-Triassic boundary (PTB) mostly relies on field observations, and resolution has thus depended on outcrop quality. This study reports on two 90 m cored sedimentary successions intersecting the PTB in Deltadalen, Svalbard, providing high-quality material to a comprehensive documentation of the stratigraphic interval. Sequence stratigraphic concepts are utilised to help constrain the Permian-Triassic basin development models in Svalbard and the high-Arctic region. The cored sections are calibrated with outcrop data from near the drill site. One core has been systematically described and scanned using 500-μm and 200-μm resolution XRF, hyperspectral imagery and microfocus CT (latter only on selected core sections). The base of both cores represents the upper 15 m of the Permian Kapp Starostin Formation, which is dominated by green glauconitic sandstones with spiculitic cherts, and exhibit various degrees of bioturbation. The Kapp Starostin Formation is in turn sharply overlain by 2 m of heavily reworked sand- and mudstones, extensively bioturbated, representing the base of the lower Triassic Vikinghøgda Formation. These bioturbated units are conformably overlain by 9 m of ash-bearing laminated black shale where signs of biological activity both on micro- and macro-scale are limited, and is thus interpreted to have recorded the Permian-Triassic extinction interval. Descriptive sedimentology and sequence stratigraphic concepts reveal the onset of relative sea level rise at the Vikinghøgda Formation base. The disappearance of bioturbation and extensive presence of pyrite in the overlying laminated black shale of the Vikinghøgda Formation suggest near anoxic conditions. The maximum flooding surface is recorded 6 m above the base of the Vikinghøgda Formation, in the middle of the laminated black shale and indicates that the lower ash-layers are tied to igneous activity at a time of relatively high sea level. The remaining succession above the laminated black shale is an overall aggradational interval of interbedded clay- and siltstones of the Vikinghøgda Formation, marking the return of biological activity at its base. The Vikinghøgda Formation includes 18 preserved zircon-bearing ash-layers, providing an opportunity for accurate U/Pb dating. Detailed cyclostratigraphic analyses of the laminated black shale suggest a sedimentation rate of approximately 0.5 cm/kyr, and provides thus, together with the U/Pb zircon ages, a great tool for high-resolution documentation of the PTB interval.

Linking innovative measurement technologies (ConMon and Dataflow© systems) for high-resolution temporal and spatial dissolved oxygen criteria assessment.

PubMed

O'Leary, C A; Perry, E; Bayard, A; Wainger, L; Boynton, W R

2015-10-01

One consequence of nutrient-induced eutrophication in shallow estuarine waters is the occurrence of hypoxia and anoxia that has serious impacts on biota, habitats, and biogeochemical cycles of important elements. Because of the important role of dissolved oxygen (DO) on these ecosystem features, a variety of DO criteria have been established as indicators of system condition. However, DO dynamics are complex and vary on time scales ranging from diel to decadal and spatial scales from meters to multiple kilometers. Because of these complexities, determining DO criteria attainment or failure remains difficult. We propose a method for linking two common measurement technologies for shallow water DO criteria assessment using a Chesapeake Bay tributary as a test case. Dataflow© is a spatially intensive (30-60-m collection intervals) system used to map surface water conditions at the whole estuary scale, and ConMon is a high-frequency (15-min collection intervals) fixed station approach. The former technology is effective with spatial descriptions but poor regarding temporal resolution, while the latter provides excellent temporal but very limited spatial resolution. Our methodology for combining the strengths of these measurement technologies involved a sequence of steps. First, a statistical model of surface water DO dynamics, based on temporally intense ConMon data, was developed. The results of this model were used to calculate daily DO minimum concentrations. Second, this model was then inserted into Dataflow©-generated spatial maps of DO conditions and used to adjust measured DO concentrations to daily minimum concentrations. This information was used to assess DO criteria compliance at the full tributary scale. Model results indicated that it is vital to consider the short-term time scale DO criteria across both space and time concurrently. Large fluctuations in DO occurred within a 24-h time period, and DO dynamics varied across the length and width of the tributary. The overall result provided a more detailed and realistic characterization of the shallow water DO minimum conditions that have the potential to be extended to other tributaries and regions. Broader applications of this model include instantaneous DO criteria assessment, utilizing this model in combination with aerial remote sensing, and developing DO amplitude as an indicator of impaired water bodies.

Streaming reversal of energetic particles in the magnetotail during a substorm

NASA Technical Reports Server (NTRS)

Lui, A. T. Y.; Williams, D. J.; Eastman, T. E.; Frank, L. A.; Akasofu, S.-I.

1984-01-01

A case of reversal in the streaming anisotropy of energetic ions and in the plasma flow observed from the IMP 8 spacecraft during a substorm on February 8, 1978 is studied in detail using measurements of energetic particles, plasma, and magnetic field. Four new features emerge when high time resolution data are examined in detail. The times of streaming reversal of energetic particles in different energy ranges do not coincide with the time of plasma flow reversal. Qualitatively different velocity distributions are observed in earthward and tailward plasma flows during the observed flow reversal intervals. Strong tailward streaming of energetic particles can be detected during northward magnetic field environments and, conversely, earthward streaming in southward field environments. During the period of tailward streaming of energetic particles, earthward streaming fluxes are occasionally detected.

Efficacy of a botanical preparation for the intramammary treatment of clinical mastitis on an organic dairy farm

PubMed Central

Pinedo, Pablo; Karreman, Hubert; Bothe, Hans; Velez, Juan; Risco, Carlos

2013-01-01

The objective was to evaluate the efficacy of a botanical product (PHYTO-MAST®) for the intra-mammary treatment of clinical mastitis (CM) in dairy cows managed in an organic system. The study involved 194 naturally occurring cases of clinical mastitis. Treatment was applied every 12 hours for 3 days and cows were evaluated for clinical cure starting on day 4. Outcomes of interest consisted of mastitis resolution at day 4, time to resolution, somatic cell score (SCS) after recovery, and bacteriological cure at 14 and 28 d after treatment. There was no significant effect on clinical mastitis resolution at day 4 for treatment compared with the control group. However, there was a faster recovery for the treatment group compared to the control group with median intervals from end of treatment to recovery of 4.6 d and 6.5 d, respectively. There was no effect on the probability of a SCS < 4 (200 000 SC/mL) after treatment. No significant effects were found for treatment on bacteriological cure at days 14 and 28. PMID:24155432

Chlamydia trachomatis OmpA genotyping as a tool for studying the natural history of genital chlamydial infection.

PubMed

Geisler, W M; Black, C M; Bandea, C I; Morrison, S G

2008-12-01

To investigate the relationship of Chlamydia trachomatis (CT) outer membrane protein A (OmpA) type to the clearance of CT infection before treatment. CT OmpA genotyping, with amplification and sequencing of ompA, was utilised to study the natural history of CT infection (spontaneous resolution vs persistence) in 102 individuals with chlamydia-positive screening tests returning for treatment. CT OmpA distribution was associated with spontaneous resolution of CT, most notably with CT OmpA genotype J/Ja detected more often from the initial screening CT test than other genotypes in those who then had spontaneous resolution of CT noted at the time of treatment. Five individuals with presumed persisting CT infection had discordant CT OmpA genotypes at the screening and treatment visits, suggesting possible new interval CT infection. Clearance of chlamydia by the host before treatment may be influenced by the CT OmpA genotype infecting the host. CT OmpA genotyping may be a valuable tool in understanding the natural history of chlamydial infections.

Modeling short duration extreme precipitation patterns using copula and generalized maximum pseudo-likelihood estimation with censoring

NASA Astrophysics Data System (ADS)

Bargaoui, Zoubeida Kebaili; Bardossy, Andràs

2015-10-01

The paper aims to develop researches on the spatial variability of heavy rainfall events estimation using spatial copula analysis. To demonstrate the methodology, short time resolution rainfall time series from Stuttgart region are analyzed. They are constituted by rainfall observations on continuous 30 min time scale recorded over a network composed by 17 raingages for the period July 1989-July 2004. The analysis is performed aggregating the observations from 30 min up to 24 h. Two parametric bivariate extreme copula models, the Husler-Reiss model and the Gumbel model are investigated. Both involve a single parameter to be estimated. Thus, model fitting is operated for every pair of stations for a giving time resolution. A rainfall threshold value representing a fixed rainfall quantile is adopted for model inference. Generalized maximum pseudo-likelihood estimation is adopted with censoring by analogy with methods of univariate estimation combining historical and paleoflood information with systematic data. Only pairs of observations greater than the threshold are assumed as systematic data. Using the estimated copula parameter, a synthetic copula field is randomly generated and helps evaluating model adequacy which is achieved using Kolmogorov Smirnov distance test. In order to assess dependence or independence in the upper tail, the extremal coefficient which characterises the tail of the joint bivariate distribution is adopted. Hence, the extremal coefficient is reported as a function of the interdistance between stations. If it is less than 1.7, stations are interpreted as dependent in the extremes. The analysis of the fitted extremal coefficients with respect to stations inter distance highlights two regimes with different dependence structures: a short spatial extent regime linked to short duration intervals (from 30 min to 6 h) with an extent of about 8 km and a large spatial extent regime related to longer rainfall intervals (from 12 h to 24 h) with an extent of 34 to 38 km.

An Analysis of Aircraft Requirements to Meet United States Department of Agriculture Remote Sensing Goals

NASA Technical Reports Server (NTRS)

Arno, R. D.

1977-01-01

The survey needs of the U.S. De pa rtment of Agriculture are immense, ranging from individual crop coverage at specific intervals to general land use classification. The aggregate of all desirable resolutions and sensor types applicable to airborne platforms yields an annual survey coverage rate eqivalent to about 6 times the U.S. land area. An intermediate annual survey level equal to the U. S. area can meet all currently perceived crop survey needs and provide sample imagery over many other resource areas. This decreased survey level can be accomplished with one or two high altitude aircraft (e.g., U-2 or WB-57) or medium altitude aircraft ( such as the Learjet or Jetstar). Survey costs range from about 25 cents to several dollars per square nautical mile depending primarily on resolution requirements and the aircraft used.

Global change across the Oligocene-Miocene transition: High-resolution stable isotope records from IODP Site U1334 (equatorial Pacific Ocean)

NASA Astrophysics Data System (ADS)

Beddow, Helen M.; Liebrand, Diederik; Sluijs, Appy; Wade, Bridget S.; Lourens, Lucas J.

2016-01-01

The Oligocene-Miocene transition (OMT) (~23 Ma) is interpreted as a transient global cooling event, associated with a large-scale Antarctic ice sheet expansion. Here we present a 2.23 Myr long high-resolution (~3 kyr) benthic foraminiferal oxygen and carbon isotope (δ18O and δ13C) record from Integrated Ocean Drilling Program Site U1334 (eastern equatorial Pacific Ocean), covering the interval from 21.91 to 24.14 Ma. To date, five other high-resolution benthic foraminiferal stable isotope stratigraphies across this time interval have been published, showing a ~1‰ increase in benthic foraminiferal δ18O across the OMT. However, these records are still few and spatially limited and no clear understanding exists of the global versus local imprints. We show that trends and the amplitudes of change are similar at Site U1334 as in other high-resolution stable isotope records, suggesting that these represent global deep water signals. We create a benthic foraminiferal stable isotope stack across the OMT by combining Site U1334 with records from ODP Sites 926, 929, 1090, 1264, and 1218 to best approximate the global signal. We find that isotopic gradients between sites indicate interbasinal and intrabasinal variabilities in deep water masses and, in particular, note an offset between the equatorial Atlantic and the equatorial Pacific, suggesting that a distinct temperature gradient was present during the OMT between these deep water masses at low latitudes. A convergence in the δ18O values between infaunal and epifaunal species occurs between 22.8 and 23.2 Ma, associated with the maximum δ18O excursion at the OMT, suggesting climatic changes associated with the OMT had an effect on interspecies offsets of benthic foraminifera. Our data indicate a maximum glacioeustatic sea level change of ~50 m across the OMT.

Future VIIRS enhancements for the integrated polar-orbiting environmental satellite system

NASA Astrophysics Data System (ADS)

Puschell, Jeffery J.; Silny, John; Cook, Lacy; Kim, Eugene

2010-08-01

The Visible/Infrared Imager Radiometer Suite (VIIRS) is the next-generation imaging spectroradiometer for the future operational polar-orbiting environmental satellite system. A successful Flight Unit 1 has been delivered and integrated onto the NPP spacecraft. The flexible VIIRS architecture can be adapted and enhanced to respond to a wide range of requirements and to incorporate new technology as it becomes available. This paper reports on recent design studies to evaluate building a MW-VLWIR dispersive hyperspectral module with active cooling into the existing VIIRS architecture. Performance of a two-grating VIIRS hyperspectral module was studied across a broad trade space defined primarily by spatial sampling, spectral range, spectral sampling interval, along-track field of view and integration time. The hyperspectral module studied here provides contiguous coverage across 3.9 - 15.5 μm with a spectral sampling interval of 10 nm or better, thereby extending VIIRS spectral range to the shortwave side of the 15.5 μm CO2 band and encompassing the 6.7 μm H2O band. Spatial sampling occurs at VIIRS I-band (~0.4 km at nadir) spatial resolution with aggregation to M-band (~0.8 km) and larger pixel sizes to improve sensitivity. Radiometric sensitivity (NEdT) at a spatial resolution of ~4 km is ~0.1 K or better for a 250 K scene across a wavelength range of 4.5 μm to 15.5 μm. The large number of high spectral and spatial resolution FOVs in this instrument improves chances for retrievals of information on the physical state and composition of the atmosphere all the way to the surface in cloudy regions relative to current systems. Spectral aggregation of spatial resolution measurements to MODIS and VIIRS multispectral bands would continue legacy measurements with better sensitivity in nearly all bands. Additional work is needed to optimize spatial sampling, spectral range and spectral sampling approaches for the hyperspectral module and to further refine this powerful imager concept.

Long-term, high-resolution imaging in the mouse neocortex through a chronic cranial window

PubMed Central

Holtmaat, Anthony; Bonhoeffer, Tobias; Chow, David K; Chuckowree, Jyoti; De Paola, Vincenzo; Hofer, Sonja B; Hübener, Mark; Keck, Tara; Knott, Graham; Lee, Wei-Chung A; Mostany, Ricardo; Mrsic-Flogel, Tom D; Nedivi, Elly; Portera-Cailliau, Carlos; Svoboda, Karel; Trachtenberg, Joshua T; Wilbrecht, Linda

2011-01-01

To understand the cellular and circuit mechanisms of experience-dependent plasticity, neurons and their synapses need to be studied in the intact brain over extended periods of time. Two-photon excitation laser scanning microscopy (2PLSM), together with expression of fluorescent proteins, enables high-resolution imaging of neuronal structure in vivo. In this protocol we describe a chronic cranial window to obtain optical access to the mouse cerebral cortex for long-term imaging. A small bone flap is replaced with a coverglass, which is permanently sealed in place with dental acrylic, providing a clear imaging window with a large field of view (∼0.8–12 mm2). The surgical procedure can be completed within ∼1 h. The preparation allows imaging over time periods of months with arbitrary imaging intervals. The large size of the imaging window facilitates imaging of ongoing structural plasticity of small neuronal structures in mice, with low densities of labeled neurons. The entire dendritic and axonal arbor of individual neurons can be reconstructed. PMID:19617885

Implicitly Coordinated Detect and Avoid Capability for Safe Autonomous Operation of Small UAS

NASA Technical Reports Server (NTRS)

Balachandran, Swee; Munoz, Cesar A.; Consiglio, Maria C.

2017-01-01

As the airspace becomes increasingly shared by autonomous small Unmanned Aerial Systems (UAS), there would be a pressing need for coordination strategies so that aircraft can safely and independently maneuver around obstacles, geofences, and traffic aircraft. Explicitly coordinating resolution strategies for small UAS would require additional components such as a reliable vehicle-to-vehicle communication infrastructure and standardized protocols for information exchange that could significantly increase the cost of deploying small UAS in a shared airspace. This paper explores a novel approach that enables multiple aircraft to implicitly coordinate their resolution maneuvers. By requiring all aircraft to execute the proposed approach deterministically, it is possible for all of them to implicitly agree on the region of airspace each will be occupying in a given time interval. The proposed approach lends itself to the construction of a suitable feedback mechanism that enables the real-time execution of an implicitly conflict-free path in a closed-loop manner dealing with uncertainties in aircraft speed. If a network infrastructure is available, the proposed approach can also exploit the benefits of explicit information.

The capacity of radar, crowdsourced personal weather stations and commercial microwave links to monitor small scale urban rainfall

NASA Astrophysics Data System (ADS)

Uijlenhoet, R.; de Vos, L. W.; Leijnse, H.; Overeem, A.; Raupach, T. H.; Berne, A.

2017-12-01

For the purpose of urban rainfall monitoring high resolution rainfall measurements are desirable. Typically C-band radar can provide rainfall intensities at km grid cells every 5 minutes. Opportunistic sensing with commercial microwave links yields rainfall intensities over link paths within cities. Additionally, recent developments have made it possible to obtain large amounts of urban in situ measurements from weather amateurs in near real-time. With a known high resolution simulated rainfall event the accuracy of these three techniques is evaluated, taking into account their respective existing layouts and sampling methods. Under ideal measurement conditions, the weather station networks proves to be most promising. For accurate estimation with radar, an appropriate choice for Z-R relationship is vital. Though both the microwave links and the weather station networks are quite dense, both techniques will underestimate rainfall if not at least one link path / station captures the high intensity rainfall peak. The accuracy of each technique improves when considering rainfall at larger scales, especially by increasing time intervals, with the steepest improvements found in microwave links.

The spatial and temporal domains of modern ecology.

PubMed

Estes, Lyndon; Elsen, Paul R; Treuer, Timothy; Ahmed, Labeeb; Caylor, Kelly; Chang, Jason; Choi, Jonathan J; Ellis, Erle C

2018-05-01

To understand ecological phenomena, it is necessary to observe their behaviour across multiple spatial and temporal scales. Since this need was first highlighted in the 1980s, technology has opened previously inaccessible scales to observation. To help to determine whether there have been corresponding changes in the scales observed by modern ecologists, we analysed the resolution, extent, interval and duration of observations (excluding experiments) in 348 studies that have been published between 2004 and 2014. We found that observational scales were generally narrow, because ecologists still primarily use conventional field techniques. In the spatial domain, most observations had resolutions ≤1 m 2 and extents ≤10,000 ha. In the temporal domain, most observations were either unreplicated or infrequently repeated (>1 month interval) and ≤1 year in duration. Compared with studies conducted before 2004, observational durations and resolutions appear largely unchanged, but intervals have become finer and extents larger. We also found a large gulf between the scales at which phenomena are actually observed and the scales those observations ostensibly represent, raising concerns about observational comprehensiveness. Furthermore, most studies did not clearly report scale, suggesting that it remains a minor concern. Ecologists can better understand the scales represented by observations by incorporating autocorrelation measures, while journals can promote attentiveness to scale by implementing scale-reporting standards.

Improved accuracy of quantitative parameter estimates in dynamic contrast-enhanced CT study with low temporal resolution

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

Kim, Sun Mo, E-mail: Sunmo.Kim@rmp.uhn.on.ca; Haider, Masoom A.; Jaffray, David A.

Purpose: A previously proposed method to reduce radiation dose to patient in dynamic contrast-enhanced (DCE) CT is enhanced by principal component analysis (PCA) filtering which improves the signal-to-noise ratio (SNR) of time-concentration curves in the DCE-CT study. The efficacy of the combined method to maintain the accuracy of kinetic parameter estimates at low temporal resolution is investigated with pixel-by-pixel kinetic analysis of DCE-CT data. Methods: The method is based on DCE-CT scanning performed with low temporal resolution to reduce the radiation dose to the patient. The arterial input function (AIF) with high temporal resolution can be generated with a coarselymore » sampled AIF through a previously published method of AIF estimation. To increase the SNR of time-concentration curves (tissue curves), first, a region-of-interest is segmented into squares composed of 3 × 3 pixels in size. Subsequently, the PCA filtering combined with a fraction of residual information criterion is applied to all the segmented squares for further improvement of their SNRs. The proposed method was applied to each DCE-CT data set of a cohort of 14 patients at varying levels of down-sampling. The kinetic analyses using the modified Tofts’ model and singular value decomposition method, then, were carried out for each of the down-sampling schemes between the intervals from 2 to 15 s. The results were compared with analyses done with the measured data in high temporal resolution (i.e., original scanning frequency) as the reference. Results: The patients’ AIFs were estimated to high accuracy based on the 11 orthonormal bases of arterial impulse responses established in the previous paper. In addition, noise in the images was effectively reduced by using five principal components of the tissue curves for filtering. Kinetic analyses using the proposed method showed superior results compared to those with down-sampling alone; they were able to maintain the accuracy in the quantitative histogram parameters of volume transfer constant [standard deviation (SD), 98th percentile, and range], rate constant (SD), blood volume fraction (mean, SD, 98th percentile, and range), and blood flow (mean, SD, median, 98th percentile, and range) for sampling intervals between 10 and 15 s. Conclusions: The proposed method of PCA filtering combined with the AIF estimation technique allows low frequency scanning for DCE-CT study to reduce patient radiation dose. The results indicate that the method is useful in pixel-by-pixel kinetic analysis of DCE-CT data for patients with cervical cancer.« less

The SMAP mission combined active-passive soil moisture product at 9 km and 3km spatial resolutions

USDA-ARS?s Scientific Manuscript database

The NASA Soil Moisture Active Passive (SMAP) mission with onboard L-band radiometer and radar was launched on January 31st, 2015. The spacecraft provided high-resolution (3 km and 9 km) global soil moisture estimates at regular intervals by combining radiometer and radar observations for ~2.5 months...

High-Precision Pulse Generator

NASA Technical Reports Server (NTRS)

Katz, Richard; Kleyner, Igor

2011-01-01

A document discusses a pulse generator with subnanosecond resolution implemented with a low-cost field-programmable gate array (FPGA) at low power levels. The method used exploits the fast carry chains of certain FPGAs. Prototypes have been built and tested in both Actel AX and Xilinx Virtex 4 technologies. In-flight calibration or control can be performed by using a similar and related technique as a time interval measurement circuit by measuring a period of the stable oscillator, as the delays through the fast carry chains will vary as a result of manufacturing variances as well as the result of environmental conditions (voltage, aging, temperature, and radiation).

Differential rotation of chromosphere and photosphere in the rising phase of N22 cycle of the Sun: torsional oscillations

NASA Astrophysics Data System (ADS)

Kasinskii, V.; Kasinskaia, L. I.

2005-06-01

The angular velocities of chromosphere and photosphere are calculated for 1987-1990 on the basis of heliographic coordinates of the chromospheric flares and sunspots (Solar Geophysical Data). The time resolution accepted is 0.25 year. The mean equatorial rotations of chromosphere and photosphere practically coincide. However, the differential coefficients in the chromosphere and photosphere, b, have strongly different behaviour. The value bch - bph change regularly from ``+'' sign to ``-'' sign over two-year interval. Thus, the idea of a torsion like oscillations of ``chromosphere-photosphere'' is supported.

A Hydraulic Tomography Experiment in Fractured Sedimentary Rocks, Newark Basin, New Jersey, USA

NASA Astrophysics Data System (ADS)

Tiedeman, C. R.; Barrash, W.; Thrash, C. J.; Johnson, C. D.

2015-12-01

Hydraulic tomography was performed in July 2015 in contaminated fractured mudstone beds at the former Naval Air Warfare Center (NAWC) in the Newark Basin near Trenton, NJ using seven existing wells. The spatial arrangement of wells (in a circle of 9 m radius with one central well), the use of packers to divide the wells into multiple monitoring intervals, and the deployment of fiber optic pressure transducers enabled collection of a hydraulic tomography dataset comprising high-resolution drawdown observations at an unprecedented level of spatial detail for fractured rocks. The experiment involved 45-minute cross-hole aquifer tests, conducted by pumping from a given packer-isolated well interval and continuously monitoring drawdowns in all other well intervals. The collective set of drawdown data from all tests and intervals displays a wide range of behavior suggestive of highly heterogeneous hydraulic conductivity (K) within the tested volume, such as: drawdown curves for different well intervals crossing one another on drawdown-time plots; variable drawdown curve shapes, including linear segments on log-log plots; variable order and magnitude of time-lag and/or drawdown for intervals of a given well in response to pumping from similar fractures or stratigraphic units in different wells; and variable groupings of wells and intervals showing similar responses for different pumping tests. The observed behavior is consistent with previous testing at the NAWC indicating that K within and across individual mudstone beds can vary by orders of magnitude over scales of meters. Preliminary assessment of the drawdown data together with a rich set of geophysical logs suggests an initial conceptual model that includes densely distributed fractures of moderate K at the shallowest depths of the tested volume, connected high-K bedding-plane-parting fractures at intermediate depths, and sparse low-K fractures in the deeper rocks. Future work will involve tomographic inversion of the data to estimate the K distribution at a scale of ~1 m3 in the upper two-thirds of the investigated volume where observation density is greatest.

Grenvillian magmatism in the northern Virginia Blue Ridge: Petrologic implications of episodic granitic magma production and the significance of postorogenic A-type charnockite

USGS Publications Warehouse

Tollo, R.P.; Aleinikoff, J.N.; Borduas, E.A.; Dickin, A.P.; McNutt, R.H.; Fanning, C.M.

2006-01-01

Grenvillian (1.2 to 1.0 Ga) plutonic rocks in northern Virginia preserve evidence of episodic, mostly granitic magmatism that spanned more than 150 million years (m.y.) of crustal reworking. Crystallization ages determined by sensitive high resolution ion microprobe (SHRIMP) U-Pb isotopic analyses of zircon and monazite, combined with results from previous studies, define three periods of magmatic activity at 1183-1144 Ma (Magmatic Interval I), 1120-1111 Ma (Magmatic Interval II), and 1078-1028 Ma (Magmatic Interval III). Magmatic activity produced dominantly tholeiitic plutons composed of (1) low-silica charnockite, (2) leucogranite, (3) non-leucocratic granitoid (with or without orthopyroxene (opx)), and (4) intermediate biotite-rich granitoid. Field, petrologic, geochemical, and geochronologic data indicate that charnockite and non-charnockitic granitoids were closely associated in both space and time, indicating that presence of opx is related to magmatic conditions, not metamorphic grade. Geochemical and Nd isotopic data, combined with results from experimental studies, indicate that leucogranites (Magmatic Intervals I and III) and non-leucocratic granitoids (Magmatic Intervals I and II) were derived from parental magmas produced by either a high degree of partial melting of isotopically evolved tonalitic sources or less advanced partial melting of dominantly tonalitic sources that also included a more mafic component. Post-orogenic, circa 1050 Ma low-silica charnockite is characterized by A-type compositional affinity including high FeOt/(FeOt + MgO), Ga/Al, Zr, Nb, Y, and Zn, and was derived from parental magmas produced by partial melting of potassic mafic sources in the lower crust. Linear geochemical trends defined by leucogranites, low-silica charnockite, and biotite-rich monzogranite emplaced during Magmatic Interval III reflect differences in source-related characteristics; these features do not represent an igneous fractionation sequence. A compositional gap between circa 1160 Ma magnesian low-silica charnockite and penecontemporaneous higher silica lithologies likewise precludes a fractionation relationship among plutons intruded during Magmatic Interval I. Correspondence in timing of magmatic activity between the Blue Ridge and neighboring Mesoproterozoic terranes underscores the widespread nature of Grenvillian processes in the region.

When to be discrete: the importance of time formulation in understanding animal movement.

PubMed

McClintock, Brett T; Johnson, Devin S; Hooten, Mevin B; Ver Hoef, Jay M; Morales, Juan M

2014-01-01

Animal movement is essential to our understanding of population dynamics, animal behavior, and the impacts of global change. Coupled with high-resolution biotelemetry data, exciting new inferences about animal movement have been facilitated by various specifications of contemporary models. These approaches differ, but most share common themes. One key distinction is whether the underlying movement process is conceptualized in discrete or continuous time. This is perhaps the greatest source of confusion among practitioners, both in terms of implementation and biological interpretation. In general, animal movement occurs in continuous time but we observe it at fixed discrete-time intervals. Thus, continuous time is conceptually and theoretically appealing, but in practice it is perhaps more intuitive to interpret movement in discrete intervals. With an emphasis on state-space models, we explore the differences and similarities between continuous and discrete versions of mechanistic movement models, establish some common terminology, and indicate under which circumstances one form might be preferred over another. Counter to the overly simplistic view that discrete- and continuous-time conceptualizations are merely different means to the same end, we present novel mathematical results revealing hitherto unappreciated consequences of model formulation on inferences about animal movement. Notably, the speed and direction of movement are intrinsically linked in current continuous-time random walk formulations, and this can have important implications when interpreting animal behavior. We illustrate these concepts in the context of state-space models with multiple movement behavior states using northern fur seal (Callorhinus ursinus) biotelemetry data.

When to be discrete: The importance of time formulation in understanding animal movement

USGS Publications Warehouse

McClintock, Brett T.; Johnson, Devin S.; Hooten, Mevin B.; Ver Hoef, Jay M.; Morales, Juan M.

2014-01-01

Animal movement is essential to our understanding of population dynamics, animal behavior, and the impacts of global change. Coupled with high-resolution biotelemetry data, exciting new inferences about animal movement have been facilitated by various specifications of contemporary models. These approaches differ, but most share common themes. One key distinction is whether the underlying movement process is conceptualized in discrete or continuous time. This is perhaps the greatest source of confusion among practitioners, both in terms of implementation and biological interpretation. In general, animal movement occurs in continuous time but we observe it at fixed discrete-time intervals. Thus, continuous time is conceptually and theoretically appealing, but in practice it is perhaps more intuitive to interpret movement in discrete intervals. With an emphasis on state-space models, we explore the differences and similarities between continuous and discrete versions of mechanistic movement models, establish some common terminology, and indicate under which circumstances one form might be preferred over another. Counter to the overly simplistic view that discrete- and continuous-time conceptualizations are merely different means to the same end, we present novel mathematical results revealing hitherto unappreciated consequences of model formulation on inferences about animal movement. Notably, the speed and direction of movement are intrinsically linked in current continuous-time random walk formulations, and this can have important implications when interpreting animal behavior. We illustrate these concepts in the context of state-space models with multiple movement behavior states using northern fur seal (Callorhinus ursinus) biotelemetry data.

Some lessons and thoughts from development of an old-fashioned high-resolution atmospheric general circulation model

NASA Astrophysics Data System (ADS)

Ohfuchi, Wataru; Enomoto, Takeshi; Yoshioka, Mayumi K.; Takaya, Koutarou

2014-05-01

Some high-resolution simulations with a conventional atmospheric general circulation model (AGCM) were conducted right after the first Earth Simulator started operating in the spring of 2002. More simulations with various resolutions followed. The AGCM in this study, AFES (Agcm For the Earth Simulator), is a primitive equation spectral transform method model with a cumulus convection parameterization. In this presentation, some findings from comparisons between high and low-resolution simulations, and some future perspectives of old-fashioned AGCMs will be discussed. One obvious advantage of increasing resolution is capability of resolving the fine structures of topography and atmospheric flow. By increasing resolution from T39 (about 320 km horizontal grid interval) to T79 (160 km), to T159 (80 km) to T319 (40 km), topographic precipitation over Japan becomes increasingly realistic. This feature is necessary for climate and weather studies involving both global and local aspects. In order to resolve submesoscale (about 100 km horizontal scale) atmospheric circulation, about 10-km grid interval is necessary. Comparing T1279 (10 km) simulations with T319 ones, it is found that, for example, the intensity of heavy rain associated with Baiu front and the central pressure of typhoon become more realistic. These realistic submesoscale phenomena should have impact on larger-sale flow through dynamics and thermodynamics. An interesting finding by increasing horizontal resolution of a conventional AGCM is that some cumulus convection parameterizations, such as Arakawa-Schubert type scheme, gradually stop producing precipitation, while some others, such as Emanuel type, do not. With the former, the grid condensation increases with the model resolution to compensate. Which characteristics are more desirable is arguable but it is an important feature one has to consider when developing a high-resolution conventional AGCM. Many may think that conventional primitive equation spectral transform AGCMs, such as AFES, have no future. Developing globally homogeneous nonhydrostatic cloud resolving grid AGCMs is obviously a straightforward direction for the future. However these models will be very expensive for many users for a while, perhaps for the next some decades. On the other hand, old-fashioned AGCMs with a grid interval of 20-100 km will remain to be accurate and efficient tools for many users for many years to come. Also by coupling with a fine-resolution regional nonhydrostatic model, a conventional AGCM may overcome its limitation for use in climate and weather studies in the future.

Measurement of the Retention Time of Different Ophthalmic Formulations with Ultrahigh-Resolution Optical Coherence Tomography.

PubMed

Gagliano, Caterina; Papa, Vincenzo; Amato, Roberta; Malaguarnera, Giulia; Avitabile, Teresio

2018-04-01

Purpose/aim of the study: The purpose of this study was to measure the pre-corneal retention time of two marketed formulations (eye drops and eye gel) of a steroid-antibiotic fixed combination (FC) containing 0.1% dexamethasone and 0.3% netilmicin. Pre-corneal retention time was evaluated in 16 healthy subjects using an ultrahigh-resolution anterior segment spectral domain optical coherence tomography (OCT). All subjects randomly received both formulations of the FC (Netildex, SIFI, Italy). Central tear film thickness (CTFT) was measured before instillation (time 0) and then after 1, 10, 20, 30, 40 50, 60 and 120 min. The pre-corneal retention time was calculated by plotting CTFT as a function of time. Differences between time points and groups were analyzed by Student's t-test. CTFT increased significantly after the instillation of the eye gel formulation (p < 0.001). CTFT reached its maximum value 1 min after instillation and returned to baseline after 60 min. No effect on CTFT was observed after the instillation of eye drops. The difference between the two formulations was statistically significant at time 1 min (p < 0.0001), 10 min (p < 0.001) and 20 min (p < 0.01). The FC formulated as eye gel was retained on the ocular surface longer than the corresponding eye drop solution. Consequently, the use of the eye gel might extend the interval between instillations and decrease the frequency of administration.

Three-dimensional reconstruction and display of the heart, lungs and circulation by multiplanar X-ray scanning videodensitometry

NASA Technical Reports Server (NTRS)

Robb, R. A.; Ritman, E. L.; Wood, E. H.

1975-01-01

A device was developed which makes possible the dynamic reconstruction of the heart and lungs within the intact thorax of a living dog or human and which can record approximately 30 multiplanar X-ray images of the thorax practically instantaneously, and at frequent enough intervals of time and with sufficient density and spatial resolution to capture and resolve the most rapid changes in cardiac structural detail throughout each cardiac cycle. It can be installed in a clinical diagnostic setting as well as in a research environment and its construction and application for determination and display in real-time modes of cross sections of the functioning thorax and its contents of living animals and man is technologically feasible.

Photogrammetric portrayal of Mars topography.

USGS Publications Warehouse

Wu, S.S.C.

1979-01-01

Special photogrammetric techniques have been developed to portray Mars topography, using Mariner and Viking imaging and nonimaging topographic information and earth-based radar data. Topography is represented by the compilation of maps at three scales: global, intermediate, and very large scale. The global map is a synthesis of topographic information obtained from Mariner 9 and earth-based radar, compiled at a scale of 1:25,000,000 with a contour interval of 1 km; it gives a broad quantitative view of the planet. At intermediate scales, Viking Orbiter photographs of various resolutions are used to compile detailed contour maps of a broad spectrum of prominent geologic features; a contour interval as small as 20 m has been obtained from very high resolution orbital photography. Imagery from the Viking lander facsimile cameras permits construction of detailed, very large scale (1:10) topographic maps of the terrain surrounding the two landers; these maps have a contour interval of 1 cm. This paper presents several new detailed topographic maps of Mars.-Author

Photogrammetric portrayal of Mars topography

NASA Technical Reports Server (NTRS)

Wu, S. S. C.

1979-01-01

Special photogrammetric techniques have been developed to portray Mars topography, using Mariner and Viking imaging and nonimaging topographic information and earth-based radar data. Topography is represented by the compilation of maps at three scales: global, intermediate, and very large scale. The global map is a synthesis of topographic information obtained from Mariner 9 and earth-based radar, compiled at a scale of 1:25,000,000 with a contour interval of 1 km; it gives a broad quantitative view of the planet. At intermediate scales, Viking Orbiter photographs of various resolutions are used to compile detailed contour maps of a broad spectrum of prominent geologic features; a contour interval as small as 20 m has been obtained from very high resolution orbital photography. Imagery from the Viking lander facsimile cameras permits construction of detailed, very large scale (1:10) topographic maps of the terrain surrounding the two landers; these maps have a contour interval of 1 cm. This paper presents several new detailed topographic maps of Mars.

Evaluating Climate Causation of Conflict in Darfur Using Multi-temporal, Multi-resolution Satellite Image Datasets With Novel Analyses

NASA Astrophysics Data System (ADS)

Brown, I.; Wennbom, M.

2013-12-01

Climate change, population growth and changes in traditional lifestyles have led to instabilities in traditional demarcations between neighboring ethic and religious groups in the Sahel region. This has resulted in a number of conflicts as groups resort to arms to settle disputes. Such disputes often centre on or are justified by competition for resources. The conflict in Darfur has been controversially explained by resource scarcity resulting from climate change. Here we analyse established methods of using satellite imagery to assess vegetation health in Darfur. Multi-decadal time series of observations are available using low spatial resolution visible-near infrared imagery. Typically normalized difference vegetation index (NDVI) analyses are produced to describe changes in vegetation ';greenness' or ';health'. Such approaches have been widely used to evaluate the long term development of vegetation in relation to climate variations across a wide range of environments from the Arctic to the Sahel. These datasets typically measure peak NDVI observed over a given interval and may introduce bias. It is furthermore unclear how the spatial organization of sparse vegetation may affect low resolution NDVI products. We develop and assess alternative measures of vegetation including descriptors of the growing season, wetness and resource availability. Expanding the range of parameters used in the analysis reduces our dependence on peak NDVI. Furthermore, these descriptors provide a better characterization of the growing season than the single NDVI measure. Using multi-sensor data we combine high temporal/moderate spatial resolution data with low temporal/high spatial resolution data to improve the spatial representativity of the observations and to provide improved spatial analysis of vegetation patterns. The approach places the high resolution observations in the NDVI context space using a longer time series of lower resolution imagery. The vegetation descriptors derived are evaluated using independent high spatial resolution datasets that reveal the pattern and health of vegetation at metre scales. We also use climate variables to support the interpretation of these data. We conclude that the spatio-temporal patterns in Darfur vegetation and climate datasets suggest that labelling the conflict a climate-change conflict is inaccurate and premature.

Impact of population structure, effective bottleneck time, and allele frequency on linkage disequilibrium maps

PubMed Central

Zhang, Weihua; Collins, Andrew; Gibson, Jane; Tapper, William J.; Hunt, Sarah; Deloukas, Panos; Bentley, David R.; Morton, Newton E.

2004-01-01

Genetic maps in linkage disequilibrium (LD) units play the same role for association mapping as maps in centimorgans provide at much lower resolution for linkage mapping. Association mapping of genes determining disease susceptibility and other phenotypes is based on the theory of LD, here applied to relations with three phenomena. To test the theory, markers at high density along a 10-Mb continuous segment of chromosome 20q were studied in African-American, Asian, and Caucasian samples. Population structure, whether created by pooling samples from divergent populations or by the mating pattern in a mixed population, is accurately bioassayed from genotype frequencies. The effective bottleneck time for Eurasians is substantially less than for migration out of Africa, reflecting later bottlenecks. The classical dependence of allele frequency on mutation age does not hold for the generally shorter time span of inbreeding and LD. Limitation of the classical theory to mutation age justifies the assumption of constant time in a LD map, except for alleles that were rare at the effective bottleneck time or have arisen since. This assumption is derived from the Malecot model and verified in all samples. Tested measures of relative efficiency, support intervals, and localization error determine the operating characteristics of LD maps that are applicable to every sexually reproducing species, with implications for association mapping, high-resolution linkage maps, evolutionary inference, and identification of recombinogenic sequences. PMID:15604137

Impact of population structure, effective bottleneck time, and allele frequency on linkage disequilibrium maps.

PubMed

Zhang, Weihua; Collins, Andrew; Gibson, Jane; Tapper, William J; Hunt, Sarah; Deloukas, Panos; Bentley, David R; Morton, Newton E

2004-12-28

Genetic maps in linkage disequilibrium (LD) units play the same role for association mapping as maps in centimorgans provide at much lower resolution for linkage mapping. Association mapping of genes determining disease susceptibility and other phenotypes is based on the theory of LD, here applied to relations with three phenomena. To test the theory, markers at high density along a 10-Mb continuous segment of chromosome 20q were studied in African-American, Asian, and Caucasian samples. Population structure, whether created by pooling samples from divergent populations or by the mating pattern in a mixed population, is accurately bioassayed from genotype frequencies. The effective bottleneck time for Eurasians is substantially less than for migration out of Africa, reflecting later bottlenecks. The classical dependence of allele frequency on mutation age does not hold for the generally shorter time span of inbreeding and LD. Limitation of the classical theory to mutation age justifies the assumption of constant time in a LD map, except for alleles that were rare at the effective bottleneck time or have arisen since. This assumption is derived from the Malecot model and verified in all samples. Tested measures of relative efficiency, support intervals, and localization error determine the operating characteristics of LD maps that are applicable to every sexually reproducing species, with implications for association mapping, high-resolution linkage maps, evolutionary inference, and identification of recombinogenic sequences.

Recent variations in seasonality of temperature and precipitation in Canada, 1976-95

NASA Astrophysics Data System (ADS)

Whitfield, Paul H.; Bodtker, Karin; Cannon, Alex J.

2002-11-01

A previously reported analysis of rehabilitated monthly temperature and precipitation time series for several hundred stations across Canada showed generally spatially coherent patterns of variation between two decades (1976-85 and 1986-95). The present work expands that analysis to finer time scales and a greater number of stations. We demonstrate how the finer temporal resolution, at 5 day or 11 day intervals, increases the separation between clusters of recent variations in seasonal patterns of temperature and precipitation. We also expand the analysis by increasing the number of stations from only rehabilitated monthly data sets to rehabilitated daily sets, then to approximately 1500 daily observation stations. This increases the spatial density of data and allows a finer spatial resolution of patterns between the two decades. We also examine the success of clustering partial records, i.e. sites where the data record is incomplete. The intent of this study was to be consistent with previous work and explore how greater temporal and spatial detail in the climate data affects the resolution of patterns of recent climate variations. The variations we report for temperature and precipitation are taking place at different temporal and spatial scales. Further, the spatial patterns are much broader than local climate regions and ecozones, indicating that the differences observed may be the result of variations in atmospheric circulation.

Unprecented syntonization and syncronization accuracy via simultaneous viewing with GPS receivers: Construction characteristics of an NBS/GPS receiver

NASA Technical Reports Server (NTRS)

Davis, D. D.; Weiss, M.; Clements, A.; Allan, D. W.

1982-01-01

The National Bureau of Standards/Global Positioning System (NBS/GPS) receiver is discussed. It is designed around the concept of obtaining high accuracy, low cost time and frequency comparisons between remote frequency standards and clocks with the intent to aid international time and frequency coordination. Preliminary tests of this comparison technique between Boulder, CO and Washington, D.C indicate the ability to do accurate time transfer to better that 10 ns, and frequency measurements to better than 1 part in 10 to the 14th power. The hardware and software of the receiver is detailed. The receiver is fully automatic with a built-in 0.1 ns resolution time interval counter. A microprocessor does data processing. Satellite signal stabilities are routinely at the 5 ns level for 15 s averages, and the internal receiver stabilities are at the 1 ns level.

Scientific requirements for a Moderate-Resolution Imaging Spectrometer (MODIS) for EOS

NASA Technical Reports Server (NTRS)

Barnes, W. L.

1985-01-01

The MODIS is an instrument planned for the sun-synchronous polar orbiting segment of the Space Station system. The radiometer is required to have 1 km resolution in terrestrial remote sensing applications. The monitoring program is targeted to last 10 yr in order to provide a sufficient database for discerning trends as opposed to natural variations. The study areas of interest include tropical deforestation, regrowth and areal distributions, acid rain effects on northern forests, desertification rates and locations, snow cover/albedo relationships and total biomass. MODIS will have 192 channels with 30 m spatial resolution and cover seven bands in the 3.5-12 microns interval for land viewing. Ocean studies will be carried out in 17 bands from 0.4-1.0 micron, and atmospheric scans will be performed over the land and ocean intervals at narrowband wavelengths (1.2 nm). Si detector arrays will be used and will be accompanied by an expected 600:1 SNR and produce data at a rate of 1.4-9.1 Mb/sec.

System implications of the ambulance arrival-to-patient contact interval on response interval compliance.

PubMed

Campbell, J P; Gratton, M C; Salomone, J A; Lindholm, D J; Watson, W A

1994-01-01

In some emergency medical services (EMS) system designs, response time intervals are mandated with monetary penalties for noncompliance. These times are set with the goal of providing rapid, definitive patient care. The time interval of vehicle at scene-to-patient access (VSPA) has been measured, but its effect on response time interval compliance has not been determined. To determine the effect of the VSPA interval on the mandated code 1 (< 9 min) and code 2 (< 13 min) response time interval compliance in an urban, public-utility model system. A prospective, observational study used independent third-party riders to collect the VSPA interval for emergency life-threatening (code 1) and emergency nonlife-threatening (code 2) calls. The VSPA interval was added to the 9-1-1 call-to-dispatch and vehicle dispatch-to-scene intervals to determine the total time interval from call received until paramedic access to the patient (9-1-1 call-to-patient access). Compliance with the mandated response time intervals was determined using the traditional time intervals (9-1-1 call-to-scene) plus the VSPA time intervals (9-1-1 call-to-patient access). Chi-square was used to determine statistical significance. Of the 216 observed calls, 198 were matched to the traditional time intervals. Sixty-three were code 1, and 135 were code 2. Of the code 1 calls, 90.5% were compliant using 9-1-1 call-to-scene intervals dropping to 63.5% using 9-1-1 call-to-patient access intervals (p < 0.0005). Of the code 2 calls, 94.1% were compliant using 9-1-1 call-to-scene intervals. Compliance decreased to 83.7% using 9-1-1 call-to-patient access intervals (p = 0.012). The addition of the VSPA interval to the traditional time intervals impacts system response time compliance. Using 9-1-1 call-to-scene compliance as a basis for measuring system performance underestimates the time for the delivery of definitive care. This must be considered when response time interval compliances are defined.

Intermittent tremor migrations beneath Guerrero, Mexico, and implications for fault healing within the slow slip zone

NASA Astrophysics Data System (ADS)

Peng, Yajun; Rubin, Allan M.

2017-01-01

Slow slip events exhibit significant complexity in slip evolution and variations in recurrence intervals. Behavior that varies systematically with recurrence interval is likely to reflect different extents of fault healing between these events. Here we use high-resolution tremor catalogs beneath Guerrero, Mexico, to investigate the mechanics of slow slip. We observe complex tremor propagation styles, including rapid tremor migrations propagating either along the main tremor front or backward, reminiscent of those in northern Cascadia. We also find many migrations that originate well behind the front and repeatedly occupy the same source region during a tremor episode, similar to those previously reported from Shikoku, Japan. These migrations could be driven by slow slip in the surrounding regions, with recurrence intervals possibly modulated by tides. The propagation speed of these migrations decreases systematically with time since the previous migration over the same source area. Tremor amplitudes seem consistent with changes in the propagation speeds being controlled primarily by changes in the slip speeds. One interpretation is that the high propagation speeds and inferred high slip speeds during the migrations with short recurrence intervals are caused by incomplete healing within the host rock adjacent to the shear zone, which could lead to high permeability and reduced dilatant strengthening of the fault gouge. Similar processes may operate in other slow slip source regions such as Cascadia.

Theoretical evaluation of accuracy in position and size of brain activity obtained by near-infrared topography

NASA Astrophysics Data System (ADS)

Kawaguchi, Hiroshi; Hayashi, Toshiyuki; Kato, Toshinori; Okada, Eiji

2004-06-01

Near-infrared (NIR) topography can obtain a topographical distribution of the activated region in the brain cortex. Near-infrared light is strongly scattered in the head, and the volume of tissue sampled by a source-detector pair on the head surface is broadly distributed in the brain. This scattering effect results in poor resolution and contrast in the topographic image of the brain activity. In this study, a one-dimensional distribution of absorption change in a head model is calculated by mapping and reconstruction methods to evaluate the effect of the image reconstruction algorithm and the interval of measurement points for topographic imaging on the accuracy of the topographic image. The light propagation in the head model is predicted by Monte Carlo simulation to obtain the spatial sensitivity profile for a source-detector pair. The measurement points are one-dimensionally arranged on the surface of the model, and the distance between adjacent measurement points is varied from 4 mm to 28 mm. Small intervals of the measurement points improve the topographic image calculated by both the mapping and reconstruction methods. In the conventional mapping method, the limit of the spatial resolution depends upon the interval of the measurement points and spatial sensitivity profile for source-detector pairs. The reconstruction method has advantages over the mapping method which improve the results of one-dimensional analysis when the interval of measurement points is less than 12 mm. The effect of overlapping of spatial sensitivity profiles indicates that the reconstruction method may be effective to improve the spatial resolution of a two-dimensional reconstruction of topographic image obtained with larger interval of measurement points. Near-infrared topography with the reconstruction method potentially obtains an accurate distribution of absorption change in the brain even if the size of absorption change is less than 10 mm.

Analysis of School Commuting Data for Exposure Modeling Purposes

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

Xue, Jianping; McCurdy, Thomas; Burke, Janet

Human exposure models often make the simplifying assumption that school children attend school in the same census tract where they live. This paper analyzes that assumption and provides information on the temporal and spatial distributions associated with school commuting. The data were obtained using Oak Ridge National Laboratory s LandScan USA population distribution model (Bhaduri et al., 2007) applied to Philadelphia PA. It is a high-resolution model used to allocate individual school-aged children to both a home and school location, and to devise a minimum-time home-to school commuting path (called a trace) between the two locations. LandScan relies heavily onmore » Geographic Information System (GIS) data. Our GIS analyses found that in Philadelphia: (1) about 32% of the students walk across 2 or more census tracts and 40% of them walk across 4 or more census blocks; (2) 60% drive across 4 or more census tracts going to school and 50% drive across 10 or more census blocks; (3) five-minute commuting time intervals result in misclassification as high as 90% for census blocks, 70% for block groups, and 50% for census tracts; (4) a one-minute time interval is needed to reasonably resolve time spent in the various census unit designations; (5) approximately 50% of both schoolchildren s homes and schools are located within 160 m of highly-traveled roads, and 64% of the schools are located within 200 m. These findings are very important when modeling school children s exposures, especially when ascertaining the impacts of near-roadway concentrations on their total daily body burden. Since many school children also travel along these streets and roadways to get to school, a majority of children in Philadelphia are in mobile-source dominated locations most of the day. We hypothesize that exposures of school children in Philadelphia to benzene and particulate matter will be much higher than if home and school locations and commuting paths at a 1-minute time resolution are not explicitly modeled in an exposure assessment. Undertaking such an assessment will be the topic of a future paper.« less

A volcanic event forecasting model for multiple tephra records, demonstrated on Mt. Taranaki, New Zealand

NASA Astrophysics Data System (ADS)

Damaschke, Magret; Cronin, Shane J.; Bebbington, Mark S.

2018-01-01

Robust time-varying volcanic hazard assessments are difficult to develop, because they depend upon having a complete and extensive eruptive activity record. Missing events in eruption records are endemic, due to poor preservation or erosion of tephra and other volcanic deposits. Even with many stratigraphic studies, underestimation or overestimation of eruption numbers is possible due to mis-matching tephras with similar chemical compositions or problematic age models. It is also common to have gaps in event coverage due to sedimentary records not being available in all directions from the volcano, especially downwind. Here, we examine the sensitivity of probabilistic hazard estimates using a suite of four new and two existing high-resolution tephra records located around Mt. Taranaki, New Zealand. Previous estimates were made using only single, or two correlated, tephra records. In this study, tephra data from six individual sites in lake and peat bogs covering an arc of 120° downwind of the volcano provided an excellent temporal high-resolution event record. The new data confirm a previously identified semi-regular pattern of variable eruption frequency at Mt. Taranaki. Eruption intervals exhibit a bimodal distribution, with eruptions being an average of 65 years apart, and in 2% of cases, centuries separate eruptions. The long intervals are less common than seen in earlier studies, but they have not disappeared with the inclusion of our comprehensive new dataset. Hence, the latest long interval of quiescence, since AD 1800, is unusual, but not out of character with the volcano. The new data also suggest that one of the tephra records (Lake Rotokare) used in earlier work had an old carbon effect on age determinations. This shifted ages of the affected tephras so that they were not correlated to other sites, leading to an artificially high eruption frequency in the previous combined record. New modelled time-varying frequency estimates suggest a 33-42% probability of an explosive eruption from Mt. Taranaki in the next 50 years, which is significantly lower than suggested by previous studies. This work also demonstrates some of the pitfalls to be avoided in combining stratigraphic records for eruption forecasting.

Looking into the puparium: Micro-CT visualization of the internal morphological changes during metamorphosis of the blow fly, Calliphora vicina, with the first quantitative analysis of organ development in cyclorrhaphous dipterans.

PubMed

Martín-Vega, Daniel; Simonsen, Thomas J; Hall, Martin J R

2017-05-01

Metamorphosis of cyclorrhaphous flies takes place inside a barrel-like puparium, formed by the shrinking, hardening and darkening of the third-instar larval cuticle. The opacity of this structure hampers the visualization of the morphological changes occurring inside and therefore a full understanding of the metamorphosis process. Here, we use micro-computed tomography (micro-CT) to describe the internal morphological changes that occur during metamorphosis of the blow fly, Calliphora vicina Robineau-Desvoidy 1830 (Diptera: Calliphoridae) at a greater temporal resolution than anything hitherto published. The morphological changes were documented at 10% intervals of the total intra-puparial period, and down to 2.5% intervals during the first 20% interval, when the most dramatic morphological changes occur. Moreover, the development of an internal gas bubble, which plays an essential role during early metamorphosis, was further investigated with X-ray images and micro-CT virtual sections. The origin of this gas bubble has been largely unknown, but micro-CT virtual sections show that it is connected to one of the main tracheal trunks. Micro-CT virtual sections also provided enough resolution for determining the completion of the larval-pupal and pupal-adult apolyses, thus enabling an accurate timing of the different intra-puparial life stages. The prepupal, pupal, and pharate adult stages last for 7.5%, 22.5%, and 70% of the total intra-puparial development, respectively. Furthermore, we provide for the first time quantitative data on the development of two organ systems of the blow fly: the alimentary canal and the indirect flight muscles. There is a significant and negative correlation between the volume of the indirect flight muscles and the pre-helicoidal region of the midgut during metamorphosis. The latter occupies a large portion of the thorax during the pupal stage but narrows progressively as the indirect flight muscles increase in volume during the development of the pharate adult. © 2017 The Authors Journal of Morphology Published by Wiley Periodicals, Inc.

Looking into the puparium: Micro‐CT visualization of the internal morphological changes during metamorphosis of the blow fly, Calliphora vicina, with the first quantitative analysis of organ development in cyclorrhaphous dipterans

PubMed Central

Simonsen, Thomas J.; Hall, Martin J. R.

2017-01-01

Abstract Metamorphosis of cyclorrhaphous flies takes place inside a barrel‐like puparium, formed by the shrinking, hardening and darkening of the third‐instar larval cuticle. The opacity of this structure hampers the visualization of the morphological changes occurring inside and therefore a full understanding of the metamorphosis process. Here, we use micro‐computed tomography (micro‐CT) to describe the internal morphological changes that occur during metamorphosis of the blow fly, Calliphora vicina Robineau‐Desvoidy 1830 (Diptera: Calliphoridae) at a greater temporal resolution than anything hitherto published. The morphological changes were documented at 10% intervals of the total intra‐puparial period, and down to 2.5% intervals during the first 20% interval, when the most dramatic morphological changes occur. Moreover, the development of an internal gas bubble, which plays an essential role during early metamorphosis, was further investigated with X‐ray images and micro‐CT virtual sections. The origin of this gas bubble has been largely unknown, but micro‐CT virtual sections show that it is connected to one of the main tracheal trunks. Micro‐CT virtual sections also provided enough resolution for determining the completion of the larval‐pupal and pupal‐adult apolyses, thus enabling an accurate timing of the different intra‐puparial life stages. The prepupal, pupal, and pharate adult stages last for 7.5%, 22.5%, and 70% of the total intra‐puparial development, respectively. Furthermore, we provide for the first time quantitative data on the development of two organ systems of the blow fly: the alimentary canal and the indirect flight muscles. There is a significant and negative correlation between the volume of the indirect flight muscles and the pre‐helicoidal region of the midgut during metamorphosis. The latter occupies a large portion of the thorax during the pupal stage but narrows progressively as the indirect flight muscles increase in volume during the development of the pharate adult. PMID:28182298

eMODIS: A User-Friendly Data Source

USGS Publications Warehouse

Jenkerson, Calli B.; Maiersperger, Thomas; Schmidt, Gail

2010-01-01

The U.S. Geological Survey's (USGS) Earth Resources Observation and Science (EROS) Center is generating a suite of products called 'eMODIS' based on Moderate Resolution Imaging Spectroradiometer (MODIS) data acquired by the National Aeronautics and Space Administration's (NASA) Earth Observing System (EOS). With a more frequent repeat cycle than Landsat and higher spatial resolutions than the Advanced Very High Resolution Spectroradiometer (AVHRR), MODIS is well suited for vegetation studies. For operational monitoring, however, the benefits of MODIS are counteracted by usability issues with the standard map projection, file format, composite interval, high-latitude 'bow-tie' effects, and production latency. eMODIS responds to a community-specific need for alternatively packaged MODIS data, addressing each of these factors for real-time monitoring and historical trend analysis. eMODIS processes calibrated radiance data (level-1B) acquired by the MODIS sensors on the EOS Terra and Aqua satellites by combining MODIS Land Science Collection 5 Atmospherically Corrected Surface Reflectance production code and USGS EROS MODIS Direct Broadcast System (DBS) software to create surface reflectance and Normalized Difference Vegetation Index (NDVI) products. eMODIS is produced over the continental United States and over Alaska extending into Canada to cover the Yukon River Basin. The 250-meter (m), 500-m, and 1,000-m products are delivered in Geostationary Earth Orbit Tagged Image File Format (Geo- TIFF) and composited in 7-day intervals. eMODIS composites are projected to non-Sinusoidal mapping grids that best suit the geography in their areas of application (see eMODIS Product Description below). For eMODIS products generated over the continental United States (eMODIS CONUS), the Terra (from 2000) and Aqua (from 2002) records are available and continue through present time. eMODIS CONUS also is generated in an expedited process that delivers a 7-day rolling composite, created daily with the most recent 7 days of acquisition, to users monitoring real-time vegetation conditions. eMODIS Alaska is not part of expedited processing, but does cover the Terra mission life (2000-present). A simple file transfer protocol (FTP) distribution site currently is enabled on the Internet for direct download of eMODIS products (ftp://emodisftp.cr.usgs.gov/eMODIS), with plans to expand into an interactive portal environment.

A high-resolution peat record from NW Iran reveals several episodes of enhanced atmospheric dust during the last 14000 years

NASA Astrophysics Data System (ADS)

Sharifi, O.; Pourmand, A.

2010-12-01

West Asia, which extends from Iran and the Arabian Peninsula to eastern Mediterranean Sea, is one of the most climatically dynamic regions in the northern hemisphere. The interactions between the mid-latitude Westerlies, the Siberian Anticyclone (SA) and the Indian Ocean Summer Monsoon (IOSM) control precipitation and atmospheric dust content across West Asia. There is mounting evidence that rise and fall of some of the earliest human societies in the “Fertile Crescent” may be related to periods of abrupt climate change during the Holocene. Nevertheless, high-resolution records of climate variability are scarce from this region and the existing archives are, in part, contradictory; while pollen and planktonic abundances from lakes in central and east Turkey and western Iran suggest dry conditions during the early-middle Holocene, geochemical data indicate relatively wet conditions prevailed during this interval. In order to address these discrepancies and study the interplay between major synoptic regimes in West Asia, we propose a multi-proxy approach to reconstruct changes in moisture and atmospheric dust at interannual to decadal time-scales during the last glacial termination and the Holocene using peat records. X-ray florescent analyses of conservative lithogenic elements (e.g., Al, Zr, Ti) in a 772-cm peat core from Neor mire in NW Iran reveal periods of elevated dust input to this region since 14272 ± 372 cal yr B.P. The intensity patterns of redox-sensitive elements (e.g., Fe, K, Rb, Zn, Cu, Co, and V) are similar to refractory metals, which indicate an aeolian source for these elements. In addition, significant correlations between the intensity of potentially mobile elements, such as K and Rb, and Ti (K/Ti R2=0.85, Rb/Ti R2=0.95) confirm that ombrotrophic condition were sustained throughout the record. At least seven major episodes of enhanced dust deposition can be identified that may be related to southward expansion of the SA accompanied by weaker Westerlies. In contrast, stronger Westerlies and diminished IOSM may also explain delivery of dust to the region during these intervals, as evidenced by similar modern events. High-resolution radio carbon dating, discrete analyses of organic biomarkers, trace elements and stable, radiogenic isotopes, and high resolution 500µ intervals (approximately at seasonal level) XRF scanning in additional peat cores from NW Iran are underway to further investigate abrupt climate change in West Asia and its potential influence on human civilizations.

Coincidental Impact of Transcatheter Patent Foramen Ovale Closure on Migraine with and without Aura - A Comprehensive Meta-Analysis.

PubMed

Kanwar, Siddak M; Noheria, Amit; DeSimone, Christopher V; Rabinstein, Alejandro A; Asirvatham, Samuel J

2016-03-01

We analyzed the literature to assess the coincidental impact on migraines of transcatheter patent foramen ovale (PFO) closure performed for secondary stroke prevention. We searched Medline, EMBASE, and the Cochrane database for studies published up until August 2013. We included English-language studies that provided information on complete resolution or improvement in migraine headaches following PFO closure. Two study authors identified 375 original articles and both independently reviewed 32 relevant manuscripts. Data including study methodology, inclusion criteria, PFO closure and migraine outcomes were extracted manually from all eligible studies. Pooled odds (and probability) of resolution or improvement of migraine headaches were calculated using random-effects models. Twenty studies were analyzed. Most were uncontrolled studies that included a small number of patients with cryptogenic stroke who had undergone PFO closure and had variable time of followup. The probability of complete resolution of migraine with PFO closure (18 studies, 917 patients) was 0.46 (95% confidence interval 0.39, 0.53) and of any improvement in migraine (17 studies, 881 patients) was 0.78 (0.74, 0.82). There was evidence for publication bias in studies reporting on improvement in migraines (Begg's p=0.002), but not for studies on complete resolution of migraine (p=0.3). In patients with aura, the probability of complete resolution of migraine post-PFO closure was 0.54 (0.43, 0.65), and in those without aura, complete resolution occurred in 0.39 (0.29, 0.51). Among patients with unexplained stroke and migraine undergoing transcatheter PFO closure, resolution of headaches occurred in a majority of patients with aura and for a smaller proportion of patients without aura.

Detection of Chlorophyll and Leaf Area Index Dynamics from Sub-weekly Hyperspectral Imagery

NASA Technical Reports Server (NTRS)

Houborg, Rasmus; McCabe, Matthew F.; Angel, Yoseline; Middleton, Elizabeth M.

2016-01-01

Temporally rich hyperspectral time-series can provide unique time critical information on within-field variations in vegetation health and distribution needed by farmers to effectively optimize crop production. In this study, a dense time series of images were acquired from the Earth Observing-1 (EO-1) Hyperion sensor over an intensive farming area in the center of Saudi Arabia. After correction for atmospheric effects, optimal links between carefully selected explanatory hyperspectral vegetation indices and target vegetation characteristics were established using a machine learning approach. A dataset of in-situ measured leaf chlorophyll (Chll) and leaf area index (LAI), collected during five intensive field campaigns over a variety of crop types, were used to train the rule-based predictive models. The ability of the narrow-band hyperspectral reflectance information to robustly assess and discriminate dynamics in foliar biochemistry and biomass through empirical relationships were investigated. This also involved evaluations of the generalization and reproducibility of the predictions beyond the conditions of the training dataset. The very high temporal resolution of the satellite retrievals constituted a specifically intriguing feature that facilitated detection of total canopy Chl and LAI dynamics down to sub-weekly intervals. The study advocates the benefits associated with the availability of optimum spectral and temporal resolution spaceborne observations for agricultural management purposes.

InSAR analysis of surface deformation over permafrost to estimate active layer thickness based on one-dimensional heat transfer model of soils

PubMed Central

Li, Zhiwei; Zhao, Rong; Hu, Jun; Wen, Lianxing; Feng, Guangcai; Zhang, Zeyu; Wang, Qijie

2015-01-01

This paper presents a novel method to estimate active layer thickness (ALT) over permafrost based on InSAR (Interferometric Synthetic Aperture Radar) observation and the heat transfer model of soils. The time lags between the periodic feature of InSAR-observed surface deformation over permafrost and the meteorologically recorded temperatures are assumed to be the time intervals that the temperature maximum to diffuse from the ground surface downward to the bottom of the active layer. By exploiting the time lags and the one-dimensional heat transfer model of soils, we estimate the ALTs. Using the frozen soil region in southern Qinghai-Tibet Plateau (QTP) as examples, we provided a conceptual demonstration of the estimation of the InSAR pixel-wise ALTs. In the case study, the ALTs are ranging from 1.02 to 3.14 m and with an average of 1.95 m. The results are compatible with those sparse ALT observations/estimations by traditional methods, while with extraordinary high spatial resolution at pixel level (~40 meter). The presented method is simple, and can potentially be used for deriving high-resolution ALTs in other remote areas similar to QTP, where only sparse observations are available now. PMID:26480892

InSAR analysis of surface deformation over permafrost to estimate active layer thickness based on one-dimensional heat transfer model of soils.

PubMed

Li, Zhiwei; Zhao, Rong; Hu, Jun; Wen, Lianxing; Feng, Guangcai; Zhang, Zeyu; Wang, Qijie

2015-10-20

This paper presents a novel method to estimate active layer thickness (ALT) over permafrost based on InSAR (Interferometric Synthetic Aperture Radar) observation and the heat transfer model of soils. The time lags between the periodic feature of InSAR-observed surface deformation over permafrost and the meteorologically recorded temperatures are assumed to be the time intervals that the temperature maximum to diffuse from the ground surface downward to the bottom of the active layer. By exploiting the time lags and the one-dimensional heat transfer model of soils, we estimate the ALTs. Using the frozen soil region in southern Qinghai-Tibet Plateau (QTP) as examples, we provided a conceptual demonstration of the estimation of the InSAR pixel-wise ALTs. In the case study, the ALTs are ranging from 1.02 to 3.14 m and with an average of 1.95 m. The results are compatible with those sparse ALT observations/estimations by traditional methods, while with extraordinary high spatial resolution at pixel level (~40 meter). The presented method is simple, and can potentially be used for deriving high-resolution ALTs in other remote areas similar to QTP, where only sparse observations are available now.

A signature of cosmic-ray increase in AD 774-775 from tree rings in Japan.

PubMed

Miyake, Fusa; Nagaya, Kentaro; Masuda, Kimiaki; Nakamura, Toshio

2012-06-03

Increases in (14)C concentrations in tree rings could be attributed to cosmic-ray events, as have increases in (10)Be and nitrate in ice cores. The record of the past 3,000 years in the IntCal09 data set, which is a time series at 5-year intervals describing the (14)C content of trees over a period of approximately 10,000 years, shows three periods during which (14)C increased at a rate greater than 3‰ over 10 years. Two of these periods have been measured at high time resolution, but neither showed increases on a timescale of about 1 year (refs 11 and 12). Here we report (14)C measurements in annual rings of Japanese cedar trees from ad 750 to ad 820 (the remaining period), with 1- and 2-year resolution. We find a rapid increase of about 12‰ in the (14)C content from ad 774 to 775, which is about 20 times larger than the change attributed to ordinary solar modulation. When averaged over 10 years, the data are consistent with the decadal IntCal (14)C data from North American and European trees. We argue that neither a solar flare nor a local supernova is likely to have been responsible.

A comparison of the wavelet and short-time fourier transforms for Doppler spectral analysis.

PubMed

Zhang, Yufeng; Guo, Zhenyu; Wang, Weilian; He, Side; Lee, Ting; Loew, Murray

2003-09-01

Doppler spectrum analysis provides a non-invasive means to measure blood flow velocity and to diagnose arterial occlusive disease. The time-frequency representation of the Doppler blood flow signal is normally computed by using the short-time Fourier transform (STFT). This transform requires stationarity of the signal during a finite time interval, and thus imposes some constraints on the representation estimate. In addition, the STFT has a fixed time-frequency window, making it inaccurate to analyze signals having relatively wide bandwidths that change rapidly with time. In the present study, wavelet transform (WT), having a flexible time-frequency window, was used to investigate its advantages and limitations for the analysis of the Doppler blood flow signal. Representations computed using the WT with a modified Morlet wavelet were investigated and compared with the theoretical representation and those computed using the STFT with a Gaussian window. The time and frequency resolutions of these two approaches were compared. Three indices, the normalized root-mean-squared errors of the minimum, the maximum and the mean frequency waveforms, were used to evaluate the performance of the WT. Results showed that the WT can not only be used as an alternative signal processing tool to the STFT for Doppler blood flow signals, but can also generate a time-frequency representation with better resolution than the STFT. In addition, the WT method can provide both satisfactory mean frequencies and maximum frequencies. This technique is expected to be useful for the analysis of Doppler blood flow signals to quantify arterial stenoses.

Neurologic 3D MR Spectroscopic Imaging with Low-Power Adiabatic Pulses and Fast Spiral Acquisition

PubMed Central

Gagoski, Borjan A.; Sorensen, A. Gregory

2012-01-01

Purpose: To improve clinical three-dimensional (3D) MR spectroscopic imaging with more accurate localization and faster acquisition schemes. Materials and Methods: Institutional review board approval and patient informed consent were obtained. Data were acquired with a 3-T MR imager and a 32-channel head coil in phantoms, five healthy volunteers, and five patients with glioblastoma. Excitation was performed with localized adiabatic spin-echo refocusing (LASER) by using adiabatic gradient-offset independent adiabaticity wideband uniform rate and smooth truncation (GOIA-W[16,4]) pulses with 3.5-msec duration, 20-kHz bandwidth, 0.81-kHz amplitude, and 45-msec echo time. Interleaved constant-density spirals simultaneously encoded one frequency and two spatial dimensions. Conventional phase encoding (PE) (1-cm3 voxels) was performed after LASER excitation and was the reference standard. Spectra acquired with spiral encoding at similar and higher spatial resolution and with shorter imaging time were compared with those acquired with PE. Metabolite levels were fitted with software, and Bland-Altman analysis was performed. Results: Clinical 3D MR spectroscopic images were acquired four times faster with spiral protocols than with the elliptical PE protocol at low spatial resolution (1 cm3). Higher-spatial-resolution images (0.39 cm3) were acquired twice as fast with spiral protocols compared with the low-spatial-resolution elliptical PE protocol. A minimum signal-to-noise ratio (SNR) of 5 was obtained with spiral protocols under these conditions and was considered clinically adequate to reliably distinguish metabolites from noise. The apparent SNR loss was not linear with decreasing voxel sizes because of longer local T2* times. Improvement of spectral line width from 4.8 Hz to 3.5 Hz was observed at high spatial resolution. The Bland-Altman agreement between spiral and PE data is characterized by narrow 95% confidence intervals for their differences (0.12, 0.18 of their means). GOIA-W(16,4) pulses minimize chemical-shift displacement error to 2.1%, reduce nonuniformity of excitation to 5%, and eliminate the need for outer volume suppression. Conclusion: The proposed adiabatic spiral 3D MR spectroscopic imaging sequence can be performed in a standard clinical MR environment. Improvements in image quality and imaging time could enable more routine acquisition of spectroscopic data than is possible with current pulse sequences. © RSNA, 2011 PMID:22187628

Complexity of cardiovascular rhythms during head-up tilt test by entropy of patterns.

PubMed

Wejer, Dorota; Graff, Beata; Makowiec, Danuta; Budrejko, Szymon; Struzik, Zbigniew R

2017-05-01

The head-up tilt (HUT) test, which provokes transient dynamical alterations in the regulation of cardiovascular system, provides insights into complex organization of this system. Based on signals with heart period intervals (RR-intervals) and/or systolic blood pressure (SBP), differences in the cardiovascular regulation between vasovagal patients (VVS) and the healthy people group (CG) are investigated. Short-term relations among signal data represented symbolically by three-beat patterns allow to qualify and quantify the complexity of the cardiovascular regulation by Shannon entropy. Four types of patterns: permutation, ordinal, deterministic and dynamical, are used, and different resolutions of signal values in the the symbolization are applied in order to verify how entropy of patterns depends on a way in which values of signals are preprocessed. At rest, in the physiologically important signal resolution ranges, independently of the type of patterns used in estimates, the complexity of SBP signals in VVS is different from the complexity found in CG. Entropy of VVS is higher than CG what could be interpreted as substantial presence of noisy ingredients in SBP of VVS. After tilting this relation switches. Entropy of CG occurs significantly higher than VVS for SBP signals. In the case of RR-intervals and large resolutions, the complexity after the tilt becomes reduced when compared to the complexity of RR-intervals at rest for both groups. However, in the case of VVS patients this reduction is significantly stronger than in CG. Our observations about opposite switches in entropy between CG and VVS might support a hypothesis that baroreflex in VVS affects stronger the heart rate because of the inefficient regulation (possibly impaired local vascular tone alternations) of the blood pressure.

Flight Crew Responses to the Interval Management Alternative Clearances (IMAC) Experiment

NASA Technical Reports Server (NTRS)

Baxley, Brian T.; Wilson, Sara R.; Swieringa, Kurt A.; Roper, Roy D.

2016-01-01

Interval Management Alternative Clearances (IMAC) was a human-in-the-loop simulation experiment conducted to explore the efficacy and acceptability of three IM operations: CAPTURE, CROSS, and MAINTAIN. Two weeks of data collection were conducted, with each week using twelve subject pilots and four subject controllers flying ten high-density arrival scenarios into the Denver International Airport. Overall, both the IM operations and procedures were rated very favorably by the flight crew in terms of acceptability, workload, and pilot head down time. However, several critical issues were identified requiring resolution prior to real-world implementation, including the high frequency of IM speed commands, IM speed commands requiring changes to aircraft configuration, and ambiguous IM cockpit displays that did not trigger the intended pilot reaction. The results from this experiment will be used to prepare for a flight test in 2017, and to support the development of an advanced IM concept of operations by the FAA (Federal Aviation Agency) and aviation industry.

Hourly average values of solar wing parameters (flow rate and ion temperatures) according to data of measurements of the Venera-9 and Venera-10 automatic interplanetary stations on an Earth-Venus during the period June 1975 - April 1976

NASA Technical Reports Server (NTRS)

Vaysberg, O. L.; Dyachkov, A. V.; Smirnov, V. N.; Tsyrkin, K. B.; Isaeva, R. A.

1980-01-01

Four electrostatic analyzers with channel electron multipliers as detectors were used to measure solar wind ionic flow. The axes of the fields of vision of two of these analyzers were directed along the axis of the automatic interplanetary station, oriented towards the Sun, while the other two were turned in one plane at angles of +15 deg and -15 deg. The full hemisphere of the angular diagram of each analyzer was approximately 5 deg. The energetic resolution was approximately 6%, and the geometric energy was 0.002 sq cm ave. keV. Each analyzer covered an energetic range of approximately 10 in eight energetic intervals. Spectral distributions were processed in order to obtain the velocity and temperature of the protons. Tabular data show the hour interval (universal time) and the average solar wind velocity in kilometers per second.

Quasi-periodic Reversals of Radio Polarization at 17 GHz Observed in the 2002 April 21 Solar Event

NASA Astrophysics Data System (ADS)

Huang, Guangli; Lin, Jun

2006-03-01

We investigate high spatial resolution radio polarization data obtained by the Nobeyama Radioheliograph (NoRH) and high time resolution data observed with the Nobeyama Radio Polarimeters (NoRP) during the well-studied flare/CME event of 2002 April 21. A 17 GHz radio source at the loop top was seen by NoRH to move upward together with the expanding flare loops at a speed of around 10 km s-1. In the 5 minutes before the source began its upward motion, the Stokes V of the radio signals at 17 GHz showed quasi-periodic reversals between left-circular polarization (LCP) and right-circular polarization (RCP). Following this interval, the polarizations gradually turned to LCP. During this period, the polarization of the corresponding footpoint source maintained the RCP sense. The reversal of Stokes V between RCP and LCP was also detected at lower frequencies (1-2 GHz) by NoRP, without spatial resolution. The observed reversals between RCP and LCP of the radio signals from the top of the flare loop system can be taken as evidence that magnetic energy is released or energetic particles are produced at the magnetic reconnection site in a quasi-periodic fashion.

A quantitative image cytometry technique for time series or population analyses of signaling networks.

PubMed

Ozaki, Yu-ichi; Uda, Shinsuke; Saito, Takeshi H; Chung, Jaehoon; Kubota, Hiroyuki; Kuroda, Shinya

2010-04-01

Modeling of cellular functions on the basis of experimental observation is increasingly common in the field of cellular signaling. However, such modeling requires a large amount of quantitative data of signaling events with high spatio-temporal resolution. A novel technique which allows us to obtain such data is needed for systems biology of cellular signaling. We developed a fully automatable assay technique, termed quantitative image cytometry (QIC), which integrates a quantitative immunostaining technique and a high precision image-processing algorithm for cell identification. With the aid of an automated sample preparation system, this device can quantify protein expression, phosphorylation and localization with subcellular resolution at one-minute intervals. The signaling activities quantified by the assay system showed good correlation with, as well as comparable reproducibility to, western blot analysis. Taking advantage of the high spatio-temporal resolution, we investigated the signaling dynamics of the ERK pathway in PC12 cells. The QIC technique appears as a highly quantitative and versatile technique, which can be a convenient replacement for the most conventional techniques including western blot, flow cytometry and live cell imaging. Thus, the QIC technique can be a powerful tool for investigating the systems biology of cellular signaling.

Real-time bacterial microcolony counting using on-chip microscopy

NASA Astrophysics Data System (ADS)

Jung, Jae Hee; Lee, Jung Eun

2016-02-01

Observing microbial colonies is the standard method for determining the microbe titer and investigating the behaviors of microbes. Here, we report an automated, real-time bacterial microcolony-counting system implemented on a wide field-of-view (FOV), on-chip microscopy platform, termed ePetri. Using sub-pixel sweeping microscopy (SPSM) with a super-resolution algorithm, this system offers the ability to dynamically track individual bacterial microcolonies over a wide FOV of 5.7 mm × 4.3 mm without requiring a moving stage or lens. As a demonstration, we obtained high-resolution time-series images of S. epidermidis at 20-min intervals. We implemented an image-processing algorithm to analyze the spatiotemporal distribution of microcolonies, the development of which could be observed from a single bacterial cell. Test bacterial colonies with a minimum diameter of 20 μm could be enumerated within 6 h. We showed that our approach not only provides results that are comparable to conventional colony-counting assays but also can be used to monitor the dynamics of colony formation and growth. This microcolony-counting system using on-chip microscopy represents a new platform that substantially reduces the detection time for bacterial colony counting. It uses chip-scale image acquisition and is a simple and compact solution for the automation of colony-counting assays and microbe behavior analysis with applications in antibacterial drug discovery.

Real-time bacterial microcolony counting using on-chip microscopy

PubMed Central

Jung, Jae Hee; Lee, Jung Eun

2016-01-01

Observing microbial colonies is the standard method for determining the microbe titer and investigating the behaviors of microbes. Here, we report an automated, real-time bacterial microcolony-counting system implemented on a wide field-of-view (FOV), on-chip microscopy platform, termed ePetri. Using sub-pixel sweeping microscopy (SPSM) with a super-resolution algorithm, this system offers the ability to dynamically track individual bacterial microcolonies over a wide FOV of 5.7 mm × 4.3 mm without requiring a moving stage or lens. As a demonstration, we obtained high-resolution time-series images of S. epidermidis at 20-min intervals. We implemented an image-processing algorithm to analyze the spatiotemporal distribution of microcolonies, the development of which could be observed from a single bacterial cell. Test bacterial colonies with a minimum diameter of 20 μm could be enumerated within 6 h. We showed that our approach not only provides results that are comparable to conventional colony-counting assays but also can be used to monitor the dynamics of colony formation and growth. This microcolony-counting system using on-chip microscopy represents a new platform that substantially reduces the detection time for bacterial colony counting. It uses chip-scale image acquisition and is a simple and compact solution for the automation of colony-counting assays and microbe behavior analysis with applications in antibacterial drug discovery. PMID:26902822

Reliability of the Parabola Approximation Method in Heart Rate Variability Analysis Using Low-Sampling-Rate Photoplethysmography.

PubMed

Baek, Hyun Jae; Shin, JaeWook; Jin, Gunwoo; Cho, Jaegeol

2017-10-24

Photoplethysmographic signals are useful for heart rate variability analysis in practical ambulatory applications. While reducing the sampling rate of signals is an important consideration for modern wearable devices that enable 24/7 continuous monitoring, there have not been many studies that have investigated how to compensate the low timing resolution of low-sampling-rate signals for accurate heart rate variability analysis. In this study, we utilized the parabola approximation method and measured it against the conventional cubic spline interpolation method for the time, frequency, and nonlinear domain variables of heart rate variability. For each parameter, the intra-class correlation, standard error of measurement, Bland-Altman 95% limits of agreement and root mean squared relative error were presented. Also, elapsed time taken to compute each interpolation algorithm was investigated. The results indicated that parabola approximation is a simple, fast, and accurate algorithm-based method for compensating the low timing resolution of pulse beat intervals. In addition, the method showed comparable performance with the conventional cubic spline interpolation method. Even though the absolute value of the heart rate variability variables calculated using a signal sampled at 20 Hz were not exactly matched with those calculated using a reference signal sampled at 250 Hz, the parabola approximation method remains a good interpolation method for assessing trends in HRV measurements for low-power wearable applications.

Digital coincidence counting

NASA Astrophysics Data System (ADS)

Buckman, S. M.; Ius, D.

1996-02-01

This paper reports on the development of a digital coincidence-counting system which comprises a custom-built data acquisition card and associated PC software. The system has been designed to digitise the pulse-trains from two radiation detectors at a rate of 20 MSamples/s with 12-bit resolution. Through hardware compression of the data, the system can continuously record both individual pulse-shapes and the time intervals between pulses. Software-based circuits are used to process the stored pulse trains. These circuits are constructed simply by linking together icons representing various components such as coincidence mixers, time delays, single-channel analysers, deadtimes and scalers. This system enables a pair of pulse trains to be processed repeatedly using any number of different methods. Some preliminary results are presented in order to demonstrate the versatility and efficiency of this new method.

Discrete Time Rescaling Theorem: Determining Goodness of Fit for Discrete Time Statistical Models of Neural Spiking

PubMed Central

Haslinger, Robert; Pipa, Gordon; Brown, Emery

2010-01-01

One approach for understanding the encoding of information by spike trains is to fit statistical models and then test their goodness of fit. The time rescaling theorem provides a goodness of fit test consistent with the point process nature of spike trains. The interspike intervals (ISIs) are rescaled (as a function of the model’s spike probability) to be independent and exponentially distributed if the model is accurate. A Kolmogorov Smirnov (KS) test between the rescaled ISIs and the exponential distribution is then used to check goodness of fit. This rescaling relies upon assumptions of continuously defined time and instantaneous events. However spikes have finite width and statistical models of spike trains almost always discretize time into bins. Here we demonstrate that finite temporal resolution of discrete time models prevents their rescaled ISIs from being exponentially distributed. Poor goodness of fit may be erroneously indicated even if the model is exactly correct. We present two adaptations of the time rescaling theorem to discrete time models. In the first we propose that instead of assuming the rescaled times to be exponential, the reference distribution be estimated through direct simulation by the fitted model. In the second, we prove a discrete time version of the time rescaling theorem which analytically corrects for the effects of finite resolution. This allows us to define a rescaled time which is exponentially distributed, even at arbitrary temporal discretizations. We demonstrate the efficacy of both techniques by fitting Generalized Linear Models (GLMs) to both simulated spike trains and spike trains recorded experimentally in monkey V1 cortex. Both techniques give nearly identical results, reducing the false positive rate of the KS test and greatly increasing the reliability of model evaluation based upon the time rescaling theorem. PMID:20608868

High-rate dead-time corrections in a general purpose digital pulse processing system

PubMed Central

Abbene, Leonardo; Gerardi, Gaetano

2015-01-01

Dead-time losses are well recognized and studied drawbacks in counting and spectroscopic systems. In this work the abilities on dead-time correction of a real-time digital pulse processing (DPP) system for high-rate high-resolution radiation measurements are presented. The DPP system, through a fast and slow analysis of the output waveform from radiation detectors, is able to perform multi-parameter analysis (arrival time, pulse width, pulse height, pulse shape, etc.) at high input counting rates (ICRs), allowing accurate counting loss corrections even for variable or transient radiations. The fast analysis is used to obtain both the ICR and energy spectra with high throughput, while the slow analysis is used to obtain high-resolution energy spectra. A complete characterization of the counting capabilities, through both theoretical and experimental approaches, was performed. The dead-time modeling, the throughput curves, the experimental time-interval distributions (TIDs) and the counting uncertainty of the recorded events of both the fast and the slow channels, measured with a planar CdTe (cadmium telluride) detector, will be presented. The throughput formula of a series of two types of dead-times is also derived. The results of dead-time corrections, performed through different methods, will be reported and discussed, pointing out the error on ICR estimation and the simplicity of the procedure. Accurate ICR estimations (nonlinearity < 0.5%) were performed by using the time widths and the TIDs (using 10 ns time bin width) of the detected pulses up to 2.2 Mcps. The digital system allows, after a simple parameter setting, different and sophisticated procedures for dead-time correction, traditionally implemented in complex/dedicated systems and time-consuming set-ups. PMID:26289270

Discrete time rescaling theorem: determining goodness of fit for discrete time statistical models of neural spiking.

PubMed

Haslinger, Robert; Pipa, Gordon; Brown, Emery

2010-10-01

One approach for understanding the encoding of information by spike trains is to fit statistical models and then test their goodness of fit. The time-rescaling theorem provides a goodness-of-fit test consistent with the point process nature of spike trains. The interspike intervals (ISIs) are rescaled (as a function of the model's spike probability) to be independent and exponentially distributed if the model is accurate. A Kolmogorov-Smirnov (KS) test between the rescaled ISIs and the exponential distribution is then used to check goodness of fit. This rescaling relies on assumptions of continuously defined time and instantaneous events. However, spikes have finite width, and statistical models of spike trains almost always discretize time into bins. Here we demonstrate that finite temporal resolution of discrete time models prevents their rescaled ISIs from being exponentially distributed. Poor goodness of fit may be erroneously indicated even if the model is exactly correct. We present two adaptations of the time-rescaling theorem to discrete time models. In the first we propose that instead of assuming the rescaled times to be exponential, the reference distribution be estimated through direct simulation by the fitted model. In the second, we prove a discrete time version of the time-rescaling theorem that analytically corrects for the effects of finite resolution. This allows us to define a rescaled time that is exponentially distributed, even at arbitrary temporal discretizations. We demonstrate the efficacy of both techniques by fitting generalized linear models to both simulated spike trains and spike trains recorded experimentally in monkey V1 cortex. Both techniques give nearly identical results, reducing the false-positive rate of the KS test and greatly increasing the reliability of model evaluation based on the time-rescaling theorem.

VizieR Online Data Catalog: Fermi-LAT flaring gamma-ray sources from FAVA (Ackermann+, 2013)

NASA Astrophysics Data System (ADS)

Ackermann, M.; Ajello, M.; Albert, A.; Allafort, A.; Antolini, E.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Blandford, R. D.; Bloom, E. D.; Bonamente, E.; Bottacini, E.; Bouvier, A.; Brandt, T. J.; Bregeon, J.; Brigida, M.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Cavazzuti, E.; Cecchi, C.; Charles, E.; Chekhtman, A.; Cheung, C. C.; Chiang, J.; Chiaro, G.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Conrad, J.; Cutini, S.; Dalton, M.; D'Ammando, F.; de Angelis, A.; de Palma, F.; Dermer, C. D.; di Venere, L.; Drell, P. S.; Drlica-Wagner, A.; Favuzzi, C.; Fegan, S. J.; Ferrara, E. C.; Focke, W. B.; Franckowiak, A.; Fukazawa, Y.; Funk, S.; Fusco, P.; Gargano, F.; Gasparrini, D.; Germani, S.; Giglietto, N.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Grenier, I. A.; Grondin, M.-H.; Grove, J. E.; Guiriec, S.; Hadasch, D.; Hanabata, Y.; Harding, A. K.; Hayashida, M.; Hays, E.; Hewitt, J.; Hill, A. B.; Horan, D.; Hou, X.; Hughes, R. E.; Inoue, Y.; Jackson, M. S.; Jogler, T.; Johannesson, G.; Johnson, W. N.; Kamae, T.; Kataoka, J.; Kawano, T.; Knodlseder, J.; Kuss, M.; Lande, J.; Larsson, S.; Latronico, L.; Lemoine-Goumard, M.; Longo, F.; Loparco, F.; Lott, B.; Lovellette, M. N.; Lubrano, P.; Mayer, M.; Mazziotta, M. N.; McEnery, J. E.; Michelson, P. F.; Mitthumsiri, W.; Mizuno, T.; Monte, C.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nemmen, R.; Nuss, E.; Ohsugi, T.; Okumura, A.; Omodei, N.; Orienti, M.; Orlando, E.; Ormes, J. F.; Paneque, D.; Panetta, J. H.; Perkins, J. S.; Pesce-Rollins, M.; Piron, F.; Pivato, G.; Porter, T. A.; Raino, S.; Rando, R.; Razzano, M.; Reimer, A.; Reimer, O.; Romoli, C.; Roth, M.; Sanchez-Conde, M.; Scargle, J. D.; Schulz, A.; Sgro, C.; Siskind, E. J.; Spandre, G.; Spinelli, P.; Suson, D. J.; Takahashi, H.; Takeuchi, Y.; Thayer, J. G.; Thayer, J. B.; Thompson, D. J.; Tibaldo, L.; Tinivella, M.; Torres, D. F.; Tosti, G.; Troja, E.; Tronconi, V.; Usher, T. L.; Vandenbroucke, J.; Vasileiou, V.; Vianello, G.; Vitale, V.; Winer, B. L.; Wood, K. S.; Wood, M.; Yang, Z.

2015-01-01

We applied FAVA (Fermi All-sky Variability Analysis) to the first 47 months of Fermi/LAT observations (2008 August 4 to 2012 July 16 UTC), in weekly time intervals. The total number of weeks is 206. We considered two ranges of gamma-ray energy, E>100MeV and E>800MeV, to increase the sensitivity for spectrally soft and hard flares, respectively. We generate measured and expected count maps with a resolution of 0.25deg2 per pixel. We found LAT counterparts for 192 of the 215 FAVA sources. Most of the associated sources, 177, are AGNs. (2 data files).

Generation of Gigawatt Circularly Polarized Attosecond-Pulse Pairs

NASA Astrophysics Data System (ADS)

Hu, K.; Wu, H.-C.

2017-12-01

A novel scheme for generating a pair of gigawatt attosecond pulses by coherent Thomson scattering from relativistic electron sheets is proposed. With a circularly polarized relativistic laser pulse, the scattered x-ray signal can have a saddlelike temporal profile, where the lower electromagnetic frequencies are found mostly in the center region of this saddlelike profile. By filtering out the latter, we can obtain two few-attosecond pulses separated by a subfemtosecond interval, which is tunable by controlling the energy of the sheet electrons. Such a pulse pair can be useful for an attosecond pump probe at an unprecedented time resolution and for ultrafast chiral studies in molecules and materials.

Mining of hospital laboratory information systems: a model study defining age- and gender-specific reference intervals and trajectories for plasma creatinine in a pediatric population.

PubMed

Søeby, Karen; Jensen, Peter Bjødstrup; Werge, Thomas; Sørensen, Steen

2015-09-01

The knowledge of physiological fluctuation and variation of even commonly used biochemical quantities in extreme age groups and during development is sparse. This challenges the clinical interpretation and utility of laboratory tests in these age groups. To explore the utility of hospital laboratory data as a source of information, we analyzed enzymatic plasma creatinine as a model analyte in two large pediatric hospital samples. Plasma creatinine measurements from 9700 children aged 0-18 years were obtained from hospital laboratory databases and partitioned into high-resolution gender- and age-groups. Normal probability plots were used to deduce parameters of the normal distributions from healthy creatinine values in the mixed hospital datasets. Furthermore, temporal trajectories were generated from repeated measurements to examine developmental patterns in periods of changing creatinine levels. Creatinine shows great age dependence from birth throughout childhood. We computed and replicated 95% reference intervals in narrow gender and age bins and showed them to be comparable to those determined in healthy population studies. We identified pronounced transitions in creatinine levels at different time points after birth and around the early teens, which challenges the establishment and usefulness of reference intervals in those age groups. The study documents that hospital laboratory data may inform on the developmental aspects of creatinine, on periods with pronounced heterogeneity and valid reference intervals. Furthermore, part of the heterogeneity in creatinine distribution is likely due to differences in biological and chronological age of children and should be considered when using age-specific reference intervals.

A New High Resolution Climate Dataset for Climate Change Impacts Assessments in New England

NASA Astrophysics Data System (ADS)

Komurcu, M.; Huber, M.

2016-12-01

Assessing regional impacts of climate change (such as changes in extreme events, land surface hydrology, water resources, energy, ecosystems and economy) requires much higher resolution climate variables than those available from global model projections. While it is possible to run global models in higher resolution, the high computational cost associated with these simulations prevent their use in such manner. To alleviate this problem, dynamical downscaling offers a method to deliver higher resolution climate variables. As part of an NSF EPSCoR funded interdisciplinary effort to assess climate change impacts on New Hampshire ecosystems, hydrology and economy (the New Hampshire Ecosystems and Society project), we create a unique high-resolution climate dataset for New England. We dynamically downscale global model projections under a high impact emissions scenario using the Weather Research and Forecasting model (WRF) with three nested grids of 27, 9 and 3 km horizontal resolution with the highest resolution innermost grid focusing over New England. We prefer dynamical downscaling over other methods such as statistical downscaling because it employs physical equations to progressively simulate climate variables as atmospheric processes interact with surface processes, emissions, radiation, clouds, precipitation and other model components, hence eliminates fix relationships between variables. In addition to simulating mean changes in regional climate, dynamical downscaling also allows for the simulation of climate extremes that significantly alter climate change impacts. We simulate three time slices: 2006-2015, 2040-2060 and 2080-2100. This new high-resolution climate dataset (with more than 200 variables saved in hourly (six hourly) intervals for the highest resolution domain (outer two domains)) along with model input and restart files used in our WRF simulations will be publicly available for use to the broader scientific community to support in-depth climate change impacts assessments for New England. We present results focusing on future changes in New England extreme events.

Combined ICA-LORETA analysis of mismatch negativity.

PubMed

Marco-Pallarés, J; Grau, C; Ruffini, G

2005-04-01

A major challenge for neuroscience is to map accurately the spatiotemporal patterns of activity of the large neuronal populations that are believed to underlie computing in the human brain. To study a specific example, we selected the mismatch negativity (MMN) brain wave (an event-related potential, ERP) because it gives an electrophysiological index of a "primitive intelligence" capable of detecting changes, even abstract ones, in a regular auditory pattern. ERPs have a temporal resolution of milliseconds but appear to result from mixed neuronal contributions whose spatial location is not fully understood. Thus, it is important to separate these sources in space and time. To tackle this problem, a two-step approach was designed combining the independent component analysis (ICA) and low-resolution tomography (LORETA) algorithms. Here we implement this approach to analyze the subsecond spatiotemporal dynamics of MMN cerebral sources using trial-by-trial experimental data. We show evidence that a cerebral computation mechanism underlies MMN. This mechanism is mediated by the orchestrated activity of several spatially distributed brain sources located in the temporal, frontal, and parietal areas, which activate at distinct time intervals and are grouped in six main statistically independent components.

A fast-locking all-digital delay-locked loop for phase/delay generation in an FPGA

NASA Astrophysics Data System (ADS)

Zhujia, Chen; Haigang, Yang; Fei, Liu; Yu, Wang

2011-10-01

A fast-locking all-digital delay-locked loop (ADDLL) is proposed for the DDR SDRAM controller interface in a field programmable gate array (FPGA). The ADDLL performs a 90° phase-shift so that the data strobe (DQS) can enlarge the data valid window in order to minimize skew. In order to further reduce the locking time and to prevent the harmonic locking problem, a time-to-digital converter (TDC) is proposed. A duty cycle corrector (DCC) is also designed in the ADDLL to adjust the output duty cycle to 50%. The ADDLL, implemented in a commercial 0.13 μm CMOS process, occupies a total of 0.017 mm2 of active area. Measurement results show that the ADDLL has an operating frequency range of 75 to 350 MHz and a total delay resolution of 15 ps. The time interval error (TIE) of the proposed circuit is 60.7 ps.

Non-Poissonian Quantum Jumps of a Fluxonium Qubit due to Quasiparticle Excitations

NASA Astrophysics Data System (ADS)

Vool, U.; Pop, I. M.; Sliwa, K.; Abdo, B.; Wang, C.; Brecht, T.; Gao, Y. Y.; Shankar, S.; Hatridge, M.; Catelani, G.; Mirrahimi, M.; Frunzio, L.; Schoelkopf, R. J.; Glazman, L. I.; Devoret, M. H.

2014-12-01

As the energy relaxation time of superconducting qubits steadily improves, nonequilibrium quasiparticle excitations above the superconducting gap emerge as an increasingly relevant limit for qubit coherence. We measure fluctuations in the number of quasiparticle excitations by continuously monitoring the spontaneous quantum jumps between the states of a fluxonium qubit, in conditions where relaxation is dominated by quasiparticle loss. Resolution on the scale of a single quasiparticle is obtained by performing quantum nondemolition projective measurements within a time interval much shorter than T1 , using a quantum-limited amplifier (Josephson parametric converter). The quantum jump statistics switches between the expected Poisson distribution and a non-Poissonian one, indicating large relative fluctuations in the quasiparticle population, on time scales varying from seconds to hours. This dynamics can be modified controllably by injecting quasiparticles or by seeding quasiparticle-trapping vortices by cooling down in a magnetic field.

Particle identification with the ALICE Time-Of-Flight detector at the LHC

NASA Astrophysics Data System (ADS)

Alici, A.

2014-12-01

High performance Particle Identification system (PID) is a distinguishing characteristic of the ALICE experiment at the CERN Large Hadron Collider (LHC). Charged particles in the intermediate momentum range are identified in ALICE by the Time-Of-Flight (TOF) detector. The TOF exploits the Multi-gap Resistive Plate Chamber (MRPC) technology, capable of an intrinsic time resolution at the level of few tens of ps with an overall efficiency close to 100% and a large operation plateau. The full system is made of 1593 MRPC chambers with a total area of 141 m2, covering the pseudorapidity interval [-0.9,+0.9] and the full azimuthal angle. The ALICE TOF system has shown very stable operation during the first 3 years of collisions at the LHC. In this paper a summary of the system performance as well as main results with data from collisions will be reported.

Phase sensitive distributed vibration sensing based on ultraweak fiber Bragg grating array using double-pulse

NASA Astrophysics Data System (ADS)

Liu, Tao; Wang, Feng; Zhang, Xuping; Zhang, Lin; Yuan, Quan; Liu, Yu; Yan, Zhijun

2017-08-01

A distributed vibration sensing technique using double-optical-pulse based on phase-sensitive optical time-domain reflectometry (ϕ-OTDR) and an ultraweak fiber Bragg grating (UWFBG) array is proposed for the first time. The single-mode sensing fiber is integrated with the UWFBG array that has uniform spatial interval and ultraweak reflectivity. The relatively high reflectivity of the UWFBG, compared with the Rayleigh scattering, gains a high signal-to-noise ratio for the signal, which can make the system achieve the maximum detectable frequency limited by the round-trip time of the probe pulse in fiber. A corresponding experimental ϕ-OTDR system with a 4.5 km sensing fiber integrated with the UWFBG array was setup for the evaluation of the system performance. Distributed vibration sensing is successfully realized with spatial resolution of 50 m. The sensing range of the vibration frequency can cover from 3 Hz to 9 kHz.

Non-Poissonian quantum jumps of a fluxonium qubit due to quasiparticle excitations.

PubMed

Vool, U; Pop, I M; Sliwa, K; Abdo, B; Wang, C; Brecht, T; Gao, Y Y; Shankar, S; Hatridge, M; Catelani, G; Mirrahimi, M; Frunzio, L; Schoelkopf, R J; Glazman, L I; Devoret, M H

2014-12-12

As the energy relaxation time of superconducting qubits steadily improves, nonequilibrium quasiparticle excitations above the superconducting gap emerge as an increasingly relevant limit for qubit coherence. We measure fluctuations in the number of quasiparticle excitations by continuously monitoring the spontaneous quantum jumps between the states of a fluxonium qubit, in conditions where relaxation is dominated by quasiparticle loss. Resolution on the scale of a single quasiparticle is obtained by performing quantum nondemolition projective measurements within a time interval much shorter than T₁, using a quantum-limited amplifier (Josephson parametric converter). The quantum jump statistics switches between the expected Poisson distribution and a non-Poissonian one, indicating large relative fluctuations in the quasiparticle population, on time scales varying from seconds to hours. This dynamics can be modified controllably by injecting quasiparticles or by seeding quasiparticle-trapping vortices by cooling down in a magnetic field.

Synopsis of a computer program designed to interface a personal computer with the fast data acquisition system of a time-of-flight mass spectrometer

NASA Technical Reports Server (NTRS)

Bechtel, R. D.; Mateos, M. A.; Lincoln, K. A.

1988-01-01

Briefly described are the essential features of a computer program designed to interface a personal computer with the fast, digital data acquisition system of a time-of-flight mass spectrometer. The instrumentation was developed to provide a time-resolved analysis of individual vapor pulses produced by the incidence of a pulsed laser beam on an ablative material. The high repetition rate spectrometer coupled to a fast transient recorder captures complete mass spectra every 20 to 35 microsecs, thereby providing the time resolution needed for the study of this sort of transient event. The program enables the computer to record the large amount of data generated by the system in short time intervals, and it provides the operator the immediate option of presenting the spectral data in several different formats. Furthermore, the system does this with a high degree of automation, including the tasks of mass labeling the spectra and logging pertinent instrumental parameters.

First results from the NEMO Test Site

NASA Astrophysics Data System (ADS)

Riccobene, Giorgio; NEMO Collaboration

2007-03-01

The NEMO (NEutrino Mediterranean Observatory) Collaboration is constructing, 25 km E from Catania (Sicily) at 2000 m depth, an underwater test site to perform long-term tests of prototypes and new technologies for an underwater high energy neutrino detector in the Mediterranean Sea. In this framework the collaboration deployed and operated an experimental apparatus for on-line monitoring of deep-sea noise. The station is equipped with 4 hydrophones operational in the range 30 Hz - 40 kHz. This interval of frequencies matches the range suitable for acoustic detection of high energy neutrino-induced showers in water. Hydrophone signals are digitized underwater at 96 kHz sampling frequency and 24 bits resolution. A custom software was developed to record data on high resolution 4-channels PCM .le. Data are used to model underwater acoustic noise as a function of frequency and time, a mandatory parametre for future acoustic neutrino detectors. Results indicate that the average noise in the site is compatible with noise produced in condition of sea surface agitation (sea state.)

Low-level water vapor fields from the VISSR atmospheric sounder (VAS) split window channels at 11 and 12 microns. [visible infrared spin scan radiometer

NASA Technical Reports Server (NTRS)

Chesters, D.; Uccellini, L.; Robinson, W.

1982-01-01

A series of high-resolution water vapor fields were derived from the 11 and 12 micron channels of the VISSR Atmospheric Sounder (VAS) on GOES-5. The low-level tropospheric moisture content was separated from the surface and atmospheric radiances by using the differential adsorption across the 'split window' along with the average air temperature from imbedded radiosondes. Fields of precipitable water are presented in a time sequence of five false color images taken over the United States at 3-hour intervals. Vivid subsynoptic and mesoscale patterns evolve at 15 km horizontal resolution over the 12-hour observing period. Convective cloud formations develop from several areas of enhanced low-level water vapor, especially where the vertical water vapor gradient relatively strong. Independent verification at radiosonde sites indicates fairly good absolute accuracy, and the spatial and temporal continuity of the water vapor features indicates very good relative accuracy. Residual errors are dominated by radiometer noise and unresolved clouds.

Research on Geometric Calibration of Spaceborne Linear Array Whiskbroom Camera

PubMed Central

Sheng, Qinghong; Wang, Qi; Xiao, Hui; Wang, Qing

2018-01-01

The geometric calibration of a spaceborne thermal-infrared camera with a high spatial resolution and wide coverage can set benchmarks for providing an accurate geographical coordinate for the retrieval of land surface temperature. The practice of using linear array whiskbroom Charge-Coupled Device (CCD) arrays to image the Earth can help get thermal-infrared images of a large breadth with high spatial resolutions. Focusing on the whiskbroom characteristics of equal time intervals and unequal angles, the present study proposes a spaceborne linear-array-scanning imaging geometric model, whilst calibrating temporal system parameters and whiskbroom angle parameters. With the help of the YG-14—China’s first satellite equipped with thermal-infrared cameras of high spatial resolution—China’s Anyang Imaging and Taiyuan Imaging are used to conduct an experiment of geometric calibration and a verification test, respectively. Results have shown that the plane positioning accuracy without ground control points (GCPs) is better than 30 pixels and the plane positioning accuracy with GCPs is better than 1 pixel. PMID:29337885

Magellan radar to reveal secrets of enshrouded Venus

NASA Technical Reports Server (NTRS)

Saunders, R. Stephen

1990-01-01

Imaging Venus with a synthetic aperture radar (SAR) with 70 percent global coverage at 1-km optical line-pair resolution to provide a detailed global characterization of the volcanic land-forms on Venus by an integration of image data with altimetry is discussed. The Magellan radar system uses navigation predictions to preset the radar data collection parameters. The data are collected in such a way as to preserve the Doppler signature of surface elements and later they are transmitted to the earth for processing into high-resolution radar images. To maintain high accuracy, a complex on-board filter algorithm allows the altitude control logic to respond only to a narrow range of expected photon intensity levels and only to signals that occur within a small predicted interval of time. Each mapping pass images a swath of the planet that varies in width from 20 to 25 km. Since the orbital plane of the spacecraft remains fixed in the inertial space, the slow rotation of Venus continually brings new areas into view of the spacecraft.

Element Abundances in the Galactic Cosmic Rays with Atomic Number (Z) in the Interval 30 is less than or equal to Z is less than or equal to 40

NASA Technical Reports Server (NTRS)

Barbier, Louis; Binns, W. R.; Christian, E.; deNolfo, G.; Geier, S.; Israel, M. H.; Link, J. T.; Mewaldt, R. A.; Mitchell, J.; Rauch, B. F.

2004-01-01

We present new results on the elemental abundances of galactic cosmic rays with atomic number, Z, greater than 30, and comparison of these observations with abundances expected from galactic propagation of various suggested models of the cosmic-ray source. We combine preliminary results from the 2003-04 flight of the Trans-Iron Galactic Element Recorder (TIGER) cosmic-ray detector with previously reported results from the 2001-02 flight. This instrument flew over Antarctica for nearly 32 days at a mean atmospheric depth of 5.2 mb in December 2001 - January 2002. At the time of submission of this abstract, January 8, 2004, TIGER was again in the air over Antarctica having completed 22 days of an expected 30day flight at a mean atmospheric depth of about 4 nb, Data from the first flight demonstrated excellent resolution of individual elements, and we expect similar resolution from the second flight.

Elliptical storm cell modeling of digital radar data

NASA Technical Reports Server (NTRS)

Altman, F. J.

1972-01-01

A model for spatial distributions of reflectivity in storm cells was fitted to digital radar data. The data were taken with a modified WSR-57 weather radar with 2.6-km resolution. The data consisted of modified B-scan records on magnetic tape of storm cells tracked at 0 deg elevation for several hours. The MIT L-band radar with 0.8-km resolution produced cross-section data on several cells at 1/2 deg elevation intervals. The model developed uses ellipses for contours of constant effective-reflectivity factor Z with constant orientation and eccentricity within a horizontal cell cross section at a given time and elevation. The centers of the ellipses are assumed to be uniformly spaced on a straight line, with areas linearly related to log Z. All cross sections are similar at different heights (except for cell tops, bottoms, and splitting cells), especially for the highest reflectivities; wind shear causes some translation and rotation between levels. Goodness-of-fit measures and parameters of interest for 204 ellipses are considered.

California coastal processes study: Skylab. [San Pablo and San Francisco Bays

NASA Technical Reports Server (NTRS)

Pirie, D. M.; Steller, D. D. (Principal Investigator)

1975-01-01

The author has identified the following significant results. In San Pablo Bay, the patterns of dredged sediment discharges were plotted over a three month period. It was found that lithogenous particles, kept in suspension by the fresh water from the Sacramento-San Joaquin, were transported downstream to the estuarine area at varying rates depending on the river discharge level. Skylab collected California coastal imagery at limited times and not at constant intervals. Resolution, however, helped compensate for lack of coverage. Increased spatial and spectral resolution provided details not possible utilizing Landsat imagery. The S-192 data was reformatted; band by band image density stretching was utilized to enhance sediment discharge patterns entrainment, boundaries, and eddys. The 26 January 1974 Skylab 4 imagery of San Francisco Bay was taken during an exceptionally high fresh water and suspended sediment discharge period. A three pronged surface sediment pattern was visible where the Sacramento-San Joaquin Rivers entered San Pablo Bay through Carquinez Strait.

Lineage Tracking for Probing Heritable Phenotypes at Single-Cell Resolution

PubMed Central

Cottinet, Denis; Condamine, Florence; Bremond, Nicolas; Griffiths, Andrew D.; Rainey, Paul B.; de Visser, J. Arjan G. M.; Baudry, Jean; Bibette, Jérôme

2016-01-01

Determining the phenotype and genotype of single cells is central to understand microbial evolution. DNA sequencing technologies allow the detection of mutants at high resolution, but similar approaches for phenotypic analyses are still lacking. We show that a drop-based millifluidic system enables the detection of heritable phenotypic changes in evolving bacterial populations. At time intervals, cells were sampled and individually compartmentalized in 100 nL drops. Growth through 15 generations was monitored using a fluorescent protein reporter. Amplification of heritable changes–via growth–over multiple generations yields phenotypically distinct clusters reflecting variation relevant for evolution. To demonstrate the utility of this approach, we follow the evolution of Escherichia coli populations during 30 days of starvation. Phenotypic diversity was observed to rapidly increase upon starvation with the emergence of heritable phenotypes. Mutations corresponding to each phenotypic class were identified by DNA sequencing. This scalable lineage-tracking technology opens the door to large-scale phenotyping methods with special utility for microbiology and microbial population biology. PMID:27077662

Lineage Tracking for Probing Heritable Phenotypes at Single-Cell Resolution.

PubMed

Cottinet, Denis; Condamine, Florence; Bremond, Nicolas; Griffiths, Andrew D; Rainey, Paul B; de Visser, J Arjan G M; Baudry, Jean; Bibette, Jérôme

2016-01-01

Determining the phenotype and genotype of single cells is central to understand microbial evolution. DNA sequencing technologies allow the detection of mutants at high resolution, but similar approaches for phenotypic analyses are still lacking. We show that a drop-based millifluidic system enables the detection of heritable phenotypic changes in evolving bacterial populations. At time intervals, cells were sampled and individually compartmentalized in 100 nL drops. Growth through 15 generations was monitored using a fluorescent protein reporter. Amplification of heritable changes-via growth-over multiple generations yields phenotypically distinct clusters reflecting variation relevant for evolution. To demonstrate the utility of this approach, we follow the evolution of Escherichia coli populations during 30 days of starvation. Phenotypic diversity was observed to rapidly increase upon starvation with the emergence of heritable phenotypes. Mutations corresponding to each phenotypic class were identified by DNA sequencing. This scalable lineage-tracking technology opens the door to large-scale phenotyping methods with special utility for microbiology and microbial population biology.

Collection of nanoliter microdiaysate fractions in plugs for off-line in vivo chemical monitoring with up to 2 s temporal resolution

PubMed Central

Wang, Meng; Slaney, Thomas; Mabrouk, Omar; Kennedy, Robert T.

2010-01-01

An off-line in vivo neurochemical monitoring approach was developed based on collecting nanoliter microdialysate fractions as an array of “plugs” segmented by immiscible oil in a piece of Teflon tubing. The dialysis probe was integrated with the plug generator in a polydimethlysiloxane microfluidic device that could be mounted on the subject. The microfluidic device also allowed derivatization reagents to be added to the plugs for fluorescence detection of analytes. Using the device, 2 nL fractions corresponding to 1–20 ms sampling times depending upon dialysis flow rate, were collected. Because axial dispersion was prevented between them, each plug acted as a discrete sample collection vial and temporal resolution was not lost by mixing or diffusion during transport. In vitro tests of the system revealed that the temporal resolution of the system was as good as 2 s and was limited by mass transport effects within the dialysis probe. After collection of dialysate fractions, they were pumped into a glass microfluidic chip that automatically analyzed the plugs by capillary electrophoresis with laser-induced fluorescence at 50 s intervals. By using a relatively low flow rate during transfer to the chip, the temporal resolution of the samples could be preserved despite the relatively slow analysis time. The system was used to detect rapid dynamics in neuroactive amino acids evoked by microinjecting the glutamate uptake inhibitor L-trans-pyrrolidine-2,4-dicarboxylic acid (PDC) or K+ into the striatum of anesthetized rats. The resulted showed increases in neurotransmitter efflux that reached a peak in 20 s for PDC and 13 s for K+. PMID:20447417

Verification of the NWP models operated at ICM, Poland

NASA Astrophysics Data System (ADS)

Melonek, Malgorzata

2010-05-01

Interdisciplinary Centre for Mathematical and Computational Modelling, University of Warsaw (ICM) started its activity in the field of NWP in May 1997. Since this time the numerical weather forecasts covering Central Europe have been routinely published on our publicly available website. First NWP model used in ICM was hydrostatic Unified Model developed by the UK Meteorological Office. It was a mesoscale version with horizontal resolution of 17 km and 31 levels in vertical. At present two NWP non-hydrostatic models are running in quasi-operational regime. The main new UM model with 4 km horizontal resolution, 38 levels in vertical and forecats range of 48 hours is running four times a day. Second, the COAMPS model (Coupled Ocean/Atmosphere Mesoscale Prediction System) developed by the US Naval Research Laboratory, configured with the three nested grids (with coresponding resolutions of 39km, 13km and 4.3km, 30 vertical levels) are running twice a day (for 00 and 12 UTC). The second grid covers Central Europe and has forecast range of 84 hours. Results of the both NWP models, ie. COAMPS computed on 13km mesh resolution and UM, are verified against observations from the Polish synoptic stations. Verification uses surface observations and nearest grid point forcasts. Following meteorological elements are verified: air temperature at 2m, mean sea level pressure, wind speed and wind direction at 10 m and 12 hours accumulated precipitation. There are presented different statistical indices. For continous variables Mean Error(ME), Mean Absolute Error (MAE) and Root Mean Squared Error (RMSE) in 6 hours intervals are computed. In case of precipitation the contingency tables for different thresholds are computed and some of the verification scores such as FBI, ETS, POD, FAR are graphically presented. The verification sample covers nearly one year.

Ultrahigh-resolution optical coherence microscopy accurately classifies precancerous and cancerous human cervix free of labeling

PubMed Central

Zeng, Xianxu; Zhang, Xiaoan; Li, Canyu; Wang, Xiaofang; Jerwick, Jason; Xu, Tao; Ning, Yuan; Wang, Yihong; Zhang, Linlin; Zhang, Zhan; Ma, Yutao; Zhou, Chao

2018-01-01

Cervical cancer remains the fourth most common cause of cancer worldwide and the third leading cause of cancer deaths for women in developing countries. Traditional screening tools, such as human papillomavirus and Pap tests, cannot provide results in real-time and cannot localize suspicious regions. Colposcopy-directed biopsies are invasive in nature and only a few sites of the cervix may be chosen for investigation. A non-invasive, label-free and real-time imaging method with a resolution approaching that of histopathology is desirable for early detection of the disease. Methods: Ultrahigh-resolution optical coherence microscopy (OCM) is an emerging imaging technique used to obtain 3-dimensional (3-D) “optical biopsies” of biological samples with cellular resolution. In this study, 497 3-D OCM datasets from 159 specimens were collected from 92 patients. Results: Distinctive patterns for normal cervix, squamocolumnar junction, ectropion, low-grade and high-grade squamous intraepithelial lesions (LSIL and HSIL) and invasive cervical lesions were clearly observed from OCM images, which matched well with corresponding histological slides. OCM images demonstrated a sensitivity of 80% (95% confidence interval, CI, 72%-86%) and a specificity of 89% (95% CI, 84%-93%) for detecting high-risk lesions (HSIL and invasive lesions) when blindly tested by three investigators. A substantial inter-observer agreement was observed (κ=0.627), which showed high diagnostic consistency among three investigators. Conclusion: These results laid the foundation for future non-invasive optical evaluation of cervical tissue in vivo, which could lead to a less invasive and more effective screening and “see-and-treat” strategy for the management of cervical cancer. PMID:29896305

Astronomical constraints on global carbon-cycle perturbation during Oceanic Anoxic Event 2 (OAE2)

NASA Astrophysics Data System (ADS)

Li, Yong-Xiang; Montañez, Isabel P.; Liu, Zhonghui; Ma, Lifeng

2017-03-01

Oceanic Anoxic Event 2 (OAE2) was a major disturbance in global carbon cycling and transient climate disruption, triggered by a pulse of volcanic CO2. Although this well-studied perturbation to the ocean-atmosphere system offers a unique opportunity to better understand abrupt climate change in response to CO2-forcing, the origin, evolution and duration of the event are still debated due in large part to the temporal resolution of existing OAE2 records and uncertainty over the duration of the overall perturbation and C cycle shifts within it. Here we report coupled magnetic susceptibility (MS) and carbon-isotope time-series of ∼2.5 to 5 ± 0.5kyr resolution from an expanded OAE2 interval from southern Tibet, China. MS cyclicity indicates short eccentricity modulation, permitting the construction of a high-precision orbital timescale which, when integrated with the high resolution δ13Ccarb record, fully constrains the timing and nature of onset through recovery of OAE2, revealing finer-scale structure than previously recognized. Abrupt coupled shifts in δ13Ccarb and MS, and changing phase relationships in-step with transitions between high and low long eccentricity, indicate orbitally linked changes in marine carbon cycling and monsoon dynamics superimposed on repeated wholesale oceanographic changes. In particular, the high-resolution Tibetan record reveals dynamic shifts in the phasing relationship of MS and δ13 C, which suggests that the initiation of ocean anoxia was probably not orbitally forced. This finding is in sharp contrast with the paradigm of orbitally forced ocean anoxia. Conversely, the new record suggests that termination of anoxia was likely orbitally forced and superimposed on a dramatic oceanographic change.

High resolution chronology of late Cretaceous-early Tertiary events determined from 21,000 yr orbital-climatic cycles in marine sediments

NASA Technical Reports Server (NTRS)

Herbert, Timothy D.; Dhondt, Steven

1988-01-01

A number of South Atlantic sites cored by the Deep Sea Drilling Project (DSDP) recovered late Cretaceous and early Tertiary sediments with alternating light-dark, high-low carbonate content. The sedimentary oscillations were turned into time series by digitizing color photographs of core segments at a resolution of about 5 points/cm. Spectral analysis of these records indicates prominent periodicity at 25 to 35 cm in the Cretaceous intervals, and about 15 cm in the early Tertiary sediments. The absolute period of the cycles that is determined from paleomagnetic calibration at two sites is 20,000 to 25,000 yr, and almost certainly corresponds to the period of the earth's precessional cycle. These sequences therefore contain an internal chronometer to measure events across the K/T extinction boundary at this scale of resolution. The orbital metronome was used to address several related questions: the position of the K/T boundary within magnetic chron 29R, the fluxes of biogenic and detrital material to the deep sea immediately before and after the K/T event, the duration of the Sr anomaly, and the level of background climatic variability in the latest Cretaceous time. The carbonate/color cycles that were analyzed contain primary records of ocean carbonate productivity and chemistry, as evidenced by bioturbational mixing of adjacent beds and the weak lithification of the rhythmic sequences. It was concluded that sedimentary sequences that contain orbital cyclicity are capable of providing resolution of dramatic events in earth history with much greater precision than obtainable through radiometric methods. The data show no evidence for a gradual climatic deterioration prior to the K/T extinction event, and argue for a geologically rapid revolution at this horizon.

Multi-Decadal to Millennial Scale Holocene Hydrologic Variation in the Southern Hemisphere Tropics of South America

NASA Astrophysics Data System (ADS)

Ekdahl, E. J.; Fritz, S. C.; Baker, P. A.; Burns, S. J.; Coley, K.; Rigsby, C. A.

2005-12-01

Numerous sites in the Northern Hemisphere show multi-decadal to millennial scale climate variation during the Holocene, many of which have been correlated with changes in atmospheric radiocarbon production or with changes in North Atlantic oceanic circulation. The manifestation of such climate variability in the hydrology of the Southern Hemisphere tropics of South America is unclear, because of the limited number of records at suitably high resolution. In the Lake Titicaca drainage basin of Bolivia and Peru, high-resolution lacustrine records reveal the overall pattern of Holocene lake-level change, the influence of precessional forcing of the South American Summer Monsoon, and the effects of high-frequency climate variability in records of lake productivity and lake ecology. Precessional forcing of regional precipitation is evident in the Lake Titicaca basin as a massive (ca. 85 m) mid-Holocene decline in lake level beginning about 7800 cal yr BP and a subsequent rise in lake level after 4000 cal yr BP. Here we show that multi-decadal to millennial-scale climate variability, superimposed upon the envelope of change at orbital time scales, is similar in timing and pattern to the ice-rafted debris record of Holocene Bond events in the North Atlantic. A high-resolution carbon isotopic record from Lake Titicaca that spans the entire Holocene suggests that cold intervals of Holocene Bond events are periods of increased precipitation, thus indicating an anti-phasing of precipitation variation on the Altiplano relative to the Northern Hemisphere tropics. A similar pattern of variation is also evident in high-resolution (2-30 yr spacing) diatom and geochemical records that span the last 7000 yr from two smaller lakes, Lagos Umayo and Lagunillas, in the Lake Titicaca drainage basin.

Forecasting Geomagnetic Activity Using Kalman Filters

NASA Astrophysics Data System (ADS)

Veeramani, T.; Sharma, A.

2006-05-01

The coupling of energy from the solar wind to the magnetosphere leads to the geomagnetic activity in the form of storms and substorms and are characterized by indices such as AL, Dst and Kp. The geomagnetic activity has been predicted near-real time using local linear filter models of the system dynamics wherein the time series of the input solar wind and the output magnetospheric response were used to reconstruct the phase space of the system by a time-delay embedding technique. Recently, the radiation belt dynamics have been studied using a adaptive linear state space model [Rigler et al. 2004]. This was achieved by assuming a linear autoregressive equation for the underlying process and an adaptive identification of the model parameters using a Kalman filter approach. We use such a model for predicting the geomagnetic activity. In the case of substorms, the Bargatze et al [1985] data set yields persistence like behaviour when a time resolution of 2.5 minutes was used to test the model for the prediction of the AL index. Unlike the local linear filters, which are driven by the solar wind input without feedback from the observations, the Kalman filter makes use of the observations as and when available to optimally update the model parameters. The update procedure requires the prediction intervals to be long enough so that the forecasts can be used in practice. The time resolution of the data suitable for such forecasting is studied by taking averages over different durations.

High-resolution tephrochronology of the Wilson Creek Formation (Mono Lake, California) and Laschamp event using 238U-230Th SIMS dating of accessory mineral rims

NASA Astrophysics Data System (ADS)

Vazquez, Jorge A.; Lidzbarski, Marsha I.

2012-12-01

Sediments of the Wilson Creek Formation surrounding Mono Lake preserve a high-resolution archive of glacial and pluvial responses along the eastern Sierra Nevada due to late Pleistocene climate change. An absolute chronology for the Wilson Creek stratigraphy is critical for correlating the paleoclimate record to other archives in the western U.S. and the North Atlantic region. However, multiple attempts to date the Wilson Creek stratigraphy using carbonates and tephras yield discordant results due to open-system effects and radiocarbon reservoir uncertainties as well as abundant xenocrysts. New ion microprobe 238U-230Th dating of the final increments of crystallization recorded by allanite and zircon autocrysts from juvenile pyroclasts yield ages that effectively date eruption of key tephra beds and delimit the timing of basal Wilson Creek sedimentation to the interval between 26.8±2.1 and 61.7±1.9 ka. Tephra (Ash 15) erupted during the geomagnetic excursion originally designated the Mono Lake excursion yields an age of 40.8±1.9 ka, indicating that the event is instead the Laschamp excursion. The new ages support a depositional chronology from magnetostratigraphy that indicates quasi-synchronous glacial and hydrologic responses in the Sierra Nevada and Mono Basin to regional climate change, with intervals of lake filling and glacial-snowpack melting that are in phase with peaks in spring insolation.

High-resolution tephrochronology of the Wilson Creek Formation (Mono Lake, California) and Laschamp event using 238U-230Th SIMS dating of accessory mineral rims

USGS Publications Warehouse

Vazquez, Jorge A.; Lidzbarski, Marsha I.

2012-01-01

Sediments of the Wilson Creek Formation surrounding Mono Lake preserve a high-resolution archive of glacial and pluvial responses along the eastern Sierra Nevada due to late Pleistocene climate change. An absolute chronology for the Wilson Creek stratigraphy is critical for correlating the paleoclimate record to other archives in the western U.S. and the North Atlantic region. However, multiple attempts to date the Wilson Creek stratigraphy using carbonates and tephras yield discordant results due to open-system effects and radiocarbon reservoir uncertainties as well as abundant xenocrysts. New ion microprobe 238U-230Th dating of the final increments of crystallization recorded by allanite and zircon autocrysts from juvenile pyroclasts yield ages that effectively date eruption of key tephra beds and delimit the timing of basal Wilson Creek sedimentation to the interval between 26.8±2.1 and 61.7±1.9 ka. Tephra (Ash 15) erupted during the geomagnetic excursion originally designated the Mono Lake excursion yields an age of 40.8±1.9 ka, indicating that the event is instead the Laschamp excursion. The new ages support a depositional chronology from magnetostratigraphy that indicates quasi-synchronous glacial and hydrologic responses in the Sierra Nevada and Mono Basin to regional climate change, with intervals of lake filling and glacial-snowpack melting that are in phase with peaks in spring insolation.

Impact of Tactical and Strategic Weather Avoidance on Separation Assurance

NASA Technical Reports Server (NTRS)

Refai, Mohamad S.; Windhorst, Robert

2011-01-01

The ability to keep flights away from weather hazards while maintaining aircraft-to-aircraft separation is critically important. The Advanced Airspace Concept is an automation concept that implements a ground-based strategic conflict resolution algorithm for management of aircraft separation. The impact of dynamic and uncertain weather avoidance on this concept is investigated. A strategic weather rerouting system is integrated with the Advanced Airspace Concept, which also provides a tactical weather avoidance algorithm, in a fast time simulation of the Air Transportation System. Strategic weather rerouting is used to plan routes around weather in the 20 minute to two-hour time horizon. To address forecast uncertainty, flight routes are revised at 15 minute intervals. Tactical weather avoidance is used for short term trajectory adjustments (30 minute planning horizon) that are updated every minute to address any weather conflicts (instances where aircraft are predicted to pass through weather cells) that are left unresolved by strategic weather rerouting. The fast time simulation is used to assess the impact of tactical weather avoidance on the performance of automated conflict resolution as well as the impact of strategic weather rerouting on both conflict resolution and tactical weather avoidance. The results demonstrate that both tactical weather avoidance and strategic weather rerouting increase the algorithm complexity required to find aircraft conflict resolutions. Results also demonstrate that tactical weather avoidance is prone to higher airborne delay than strategic weather rerouting. Adding strategic weather rerouting to tactical weather avoidance reduces total airborne delays for the reported scenario by 18% and reduces the number of remaining weather violations by 13%. Finally, two features are identified that have proven important for strategic weather rerouting to realize these benefits; namely, the ability to revise reroutes and the use of maneuvers that start far ahead of encountering a weather cell when rerouting around weather.

Widespread Miocene deep-sea hiatuses: coincidence with periods of global cooling.

USGS Publications Warehouse

Barron, J.A.; Keller, G.

1982-01-01

High-resolution biostratigraphic analyses of Miocene deep-sea cores reveal eight intervals of widespread hiatuses in the world ocean. In complete sections these hiatuses correspond to intervals of cool faunal and floral assemblages, rapid enrichment of delta 18O, and sea-level regressions. These factors suggest that Miocene deep-sea hiatuses result from an increased intensity of circulation and corrosiveness of bottom currents during periods of increased polar refrigeration.-Authors

Demonstrating the Value of Fine-resolution Optical Data for Minimising Aliasing Impacts on Biogeochemical Models of Surface Waters

NASA Astrophysics Data System (ADS)

Chappell, N. A.; Jones, T.; Young, P.; Krishnaswamy, J.

2015-12-01

There is increasing awareness that under-sampling may have resulted in the omission of important physicochemical information present in water quality signatures of surface waters - thereby affecting interpretation of biogeochemical processes. For dissolved organic carbon (DOC) and nitrogen this under-sampling can now be avoided using UV-visible spectroscopy measured in-situ and continuously at a fine-resolution e.g. 15 minutes ("real time"). Few methods are available to extract biogeochemical process information directly from such high-frequency data. Jones, Chappell & Tych (2014 Environ Sci Technol: 13289-97) developed one such method using optically-derived DOC data based upon a sophisticated time-series modelling tool. Within this presentation we extend the methodology to quantify the minimum sampling interval required to avoid distortion of model structures and parameters that describe fundamental biogeochemical processes. This shifting of parameters which results from under-sampling is called "aliasing". We demonstrate that storm dynamics at a variety of sites dominate over diurnal and seasonal changes and that these must be characterised by sampling that may be sub-hourly to avoid aliasing. This is considerably shorter than that used by other water quality studies examining aliasing (e.g. Kirchner 2005 Phys Rev: 069902). The modelling approach presented is being developed into a generic tool to calculate the minimum sampling for water quality monitoring in systems driven primarily by hydrology. This is illustrated with fine-resolution, optical data from watersheds in temperate Europe through to the humid tropics.

Using Small Unmanned Aerial Systems to Advance Hydrological Models in Coastal Watersheds

NASA Astrophysics Data System (ADS)

Moorhead, R.; Hathcock, L.; Coffey, J. J.; Hood, R. E.; van Cooten, S.; Choate, K.; Rawson, H.; Kosturock, A.

2014-12-01

Small unmanned aerial systems (sUASs) have the potential to provide highly useful information for models of earth systems that vary over time intervals of days and for which sub-meter resolution is crucial. In particular, the state of coastal watershed plains are highly dependent on vegetation type and cover, soil type, weather, river flooding, and coastal inundation. The vegetation type and cover affect the drying potential, as well as the watershed's resistance to flood water movement. The soil type, soil moisture, and pond depths affect the ability of the watershed to absorb river flood waters and inundation from the sea. In this presentation we will describe a data collection campaign and model modification effort for hydrological models in a coastal watershed. The data collection campaign is obtaining data bimonthly using multiple UASs to capture the state of the watershed quicker. In particular, the vegetation cover and the extent of the water surface expression are captured at approximately a 1 inch spatial resolution over a few days with sUASs that can image 1-2 square miles per hour. The vegetation data provides a time-varying input to improve the estimation of the roughness coefficient and the dry potential from the traditionally static datasets. By correlating the high spatio-temporal resolution surface water expression with data from approximately ten river gauges, models can be improved and validated under more conditions. The presentation will also discuss the requisite sUAS capabilities and our experience in using them.

Late Miocene climate and orbital time scale reconciliation from a deep-sea perspective

NASA Astrophysics Data System (ADS)

Drury, Anna Joy; Westerhold, Thomas; Frederichs, Thomas; Tian, Jun; Wilkens, Roy; Channell, James E. T.; Evans, Helen; John, Cédric M.; Lyle, Mitch; Röhl, Ursula

2017-04-01

The late Tortonian to early Messinian (8-6 Ma) is characterised by a long-term reduction in benthic foraminiferal δ18O, with distinctive short-term δ18O cycles superimposed. Coevally, a permanent -1‰ change in oceanic δ13CDIC, the late Miocene carbon isotope shift (LMCIS), marks the last major permanent shift in the carbon cycle expressed in all oceanic basins, after which near-modern δ13C gradients are established around 6.7 Ma. Accurate age control is crucial to ascertain the origin of the δ18O cyclicity and the LMCIS, as constraining the precise timing of such events can allow temporal and causal relationships to be established between the deep-sea, terrestrial and cryosphere records. Here, we present the first independent high-resolution chemo-, magneto-, and cyclostratigraphy for the interval between 8.3-6.0 Ma from a single deep-sea site. Generated at equatorial Pacific Integrated Ocean Drilling Program (IODP) Site U1337, our integrated astronomically tuned benthic stable isotope stratigraphy (1.5 kyr resolution) and magnetostratigraphy is suitable to test the current Tortonian-Messinian Geological Time Scale (GTS2012), currently based on astronomically calibrated Mediterranean sections. Between 7.7-6.9 Ma, the new benthic δ18O and δ13C data from IODP U1337 show distinctive obliquity-driven saw-tooth patterns suggesting that high-latitude forcing dominated late Miocene climate dynamics. For the first time, the LMCIS is astronomically calibrated and anchored to the GPTS between Chrons C4n.1n and C3An.2n. Anchoring the LMCIS facilitates comparison with terrestrial records of the C3/C4 vegetation shift, which has been linked to the LMCIS. The astronomically calibrated Site U1337 magnetostratigraphy additionally provides robust ages for polarity Chrons C3An.1n to C4r.1r, with ages changing by 2-50 kyr relative to the GTS2012. The new integrated deep-sea stratigraphy from Site U1337 has potential as a new stable isotope and magnetic polarity reference section for the 8.3-6.0 Ma interval.

Interval Timing Is Preserved Despite Circadian Desynchrony in Rats: Constant Light and Heavy Water Studies.

PubMed

Petersen, Christian C; Mistlberger, Ralph E

2017-08-01

The mechanisms that enable mammals to time events that recur at 24-h intervals (circadian timing) and at arbitrary intervals in the seconds-to-minutes range (interval timing) are thought to be distinct at the computational and neurobiological levels. Recent evidence that disruption of circadian rhythmicity by constant light (LL) abolishes interval timing in mice challenges this assumption and suggests a critical role for circadian clocks in short interval timing. We sought to confirm and extend this finding by examining interval timing in rats in which circadian rhythmicity was disrupted by long-term exposure to LL or by chronic intake of 25% D 2 O. Adult, male Sprague-Dawley rats were housed in a light-dark (LD) cycle or in LL until free-running circadian rhythmicity was markedly disrupted or abolished. The rats were then trained and tested on 15- and 30-sec peak-interval procedures, with water restriction used to motivate task performance. Interval timing was found to be unimpaired in LL rats, but a weak circadian activity rhythm was apparently rescued by the training procedure, possibly due to binge feeding that occurred during the 15-min water access period that followed training each day. A second group of rats in LL were therefore restricted to 6 daily meals scheduled at 4-h intervals. Despite a complete absence of circadian rhythmicity in this group, interval timing was again unaffected. To eliminate all possible temporal cues, we tested a third group of rats in LL by using a pseudo-randomized schedule. Again, interval timing remained accurate. Finally, rats tested in LD received 25% D 2 O in place of drinking water. This markedly lengthened the circadian period and caused a failure of LD entrainment but did not disrupt interval timing. These results indicate that interval timing in rats is resistant to disruption by manipulations of circadian timekeeping previously shown to impair interval timing in mice.

Refining surface net radiation estimates in arid and semi-arid climates of Iran

NASA Astrophysics Data System (ADS)

Golkar, Foroogh; Rossow, William B.; Sabziparvar, Ali Akbar

2018-06-01

Although the downwelling fluxes exhibit space-time scales of dependency on characteristic of atmospheric variations, especially clouds, the upward fluxes and, hence the net radiation, depends on the variation of surface properties, particularly surface skin temperature and albedo. Evapotranspiration at the land surface depends on the properties of that surface and is determined primarily by the net surface radiation, mostly absorbed solar radiation. Thus, relatively high spatial resolution net radiation data are needed for evapotranspiration studies. Moreover, in more arid environments, the diurnal variations of surface (air and skin) temperature can be large so relatively high (sub-daily) time resolution net radiation is also needed. There are a variety of radiation and surface property products available but they differ in accuracy, space-time resolution and information content. This situation motivated the current study to evaluate multiple sources of information to obtain the best net radiation estimate with the highest space-time resolution from ISCCP FD dataset. This study investigates the accuracy of the ISCCP FD and AIRS surface air and skin temperatures, as well as the ISCCP FD and MODIS surface albedos and aerosol optical depths as the leading source of uncertainty in ISCCP FD dataset. The surface air temperatures, 10-cm soil temperatures and surface solar insolation from a number of surface sites are used to judge the best combinations of data products, especially on clear days. The corresponding surface skin temperatures in ISCCP FD, although they are known to be biased somewhat high, disagreed more with AIRS measurements because of the mismatch of spatial resolutions. The effect of spatial resolution on the comparisons was confirmed using the even higher resolution MODIS surface skin temperature values. The agreement of ISCCP FD surface solar insolation with surface measurements is good (within 2.4-9.1%), but the use of MODIS aerosol optical depths as an alternative was checked and found to not improve the agreement. The MODIS surface albedos differed from the ISCCP FD values by no more than 0.02-0.07, but because these differences are mostly at longer wavelengths, they did not change the net solar radiation very much. Therefore to obtain the best estimate of surface net radiation with the best combination of spatial and temporal resolution, we developed a method to adjust the ISCCP FD surface longwave fluxes using the AIRS surface air and skin temperatures to obtain the higher spatial resolution of the latter (45 km), while retaining the 3-h time intervals of the former. Overall, the refinements reduced the ISCCP FD longwave flux magnitudes by about 25.5-42.1 W/m2 RMS (maximum difference -27.5 W/m2 for incoming longwave radiation and -59 W/m2 for outgoing longwave radiation) with the largest differences occurring at 9:00 and 12:00 UTC near local noon. Combining the ISCCP FD net shortwave radiation data and the AIRS-modified net longwave radiation data changed the total net radiation for summertime by 4.64 to 61.5 W/m2 and for wintertime by 1.06 to 41.88 W/m2 (about 11.1-39.2% of the daily mean).

Optical Diagnostic System For Observation Of Laser-Produced Shock Waves

NASA Astrophysics Data System (ADS)

Wilke, Mark D.; Stone, Sidney N.

1980-11-01

Several standard plasma and gas dynamic diagnostic techniques have been integrated into a system for observing the formation and propagation of high-power Nd:glass-laser generated one- and two-dimensional shockwaves in air from 0.1 torr to atmospheric pres-sures. Diagnostics include either single-frame, two-wavelength holographic ruby-laser interferometry or single-frame, single-wavelength interferometry with ten frames of shadow-graphy. Streaks or ten frames of the early luminous shocked region also are taken on all shots, as well as time-resolved luminosity measurements using high-speed biplanar vacuum photodiodes with various wavelength interference filters. Shadowgraphy frames are 200-ns long at 1-μs intervals, while emission frames are variable with a maximum 10-ns exposure and 50-ns interval. Both the streak mode and emission measurements with the vacuum diode allow subnanosecond time resolution. The interferometry provides 20-ns exposures from 500 ns to late times. Methods for reducing and interpreting the data have been, or are currently being, developed. Interactive computer programs for digitizing the fringe patterns provide fringe-shift profiles for Abel inversion. This has provided neutral gas and electron density information in the spherical, one-dimensional cases. Diagrams and photographs of the experiment will be shown as well as examples of the data that have been taken. Methods for data reduction will be outlined and some of the results shown.

Burst Suppression on Processed Electroencephalography as a Predictor of Post-Coma Delirium in Mechanically Ventilated ICU Patients

PubMed Central

Andresen, Jennifer M.; Girard, Timothy D.; Pandharipande, Pratik P.; Davidson, Mario A.; Ely, E. Wesley; Watson, Paula L.

2015-01-01

Objectives Many patients, due to a combination of illness and sedatives, spend a considerable amount of time in a comatose state that can include time in burst suppression. We sought to determine if burst suppression measured by processed electroencephalography (pEEG) during coma in sedative-exposed patients is a predictor of post-coma delirium during critical illness. Design Observational convenience sample cohort Setting Medical and surgical ICUs in a tertiary care medical center Patients Cohort of 124 mechanically ventilated ICU patients Measurements and Main Results Depth of sedation was monitored twice daily using the Richmond Agitation-Sedation Scale and continuously monitored by pEEG. When non-comatose, patients were assessed for delirium twice daily using Confusion Assessment Method for the ICU (CAM-ICU). Multiple logistic regression and Cox proportional hazards regression were used to assess associations between time in burst suppression and both incidence and time to resolution of delirium, respectively, adjusting for time in deep sedation and a principal component score consisting of APACHE II score and cumulative doses of sedatives while comatose. Of the 124 patients enrolled and monitored, 55 patients either never had coma or never emerged from coma yielding 69 patients for whom we performed these analyses; 42 of these 69 (61%) had post-coma delirium. Most patients had burst-suppression during coma, though often short-lived [ median (intraquartile range) time in burst suppression, 6.4 (1-58) minutes]. After adjusting for covariates, even this short time in burst suppression independently predicted a higher incidence of post-coma delirium [odds ratio 4.16; 95% confidence interval (CI) 1.27-13.62; p=0.02] and a lower likelihood (delayed) resolution of delirium (hazard ratio 0.78; 95% CI 0.53-0.98; p=0.04). Conclusions Time in burst suppression during coma, as measured by processed EEG, was an independent predictor of incidence and time to resolution of post-coma/post-deep sedation delirium. These findings of this single center investigation support lighter sedation strategies. PMID:25072756

A cross-sectional evaluation of meditation experience on electroencephalography data by artificial neural network and support vector machine classifiers

PubMed Central

Lee, Yu-Hao; Hsieh, Ya-Ju; Shiah, Yung-Jong; Lin, Yu-Huei; Chen, Chiao-Yun; Tyan, Yu-Chang; GengQiu, JiaCheng; Hsu, Chung-Yao; Chen, Sharon Chia-Ju

2017-01-01

Abstract To quantitate the meditation experience is a subjective and complex issue because it is confounded by many factors such as emotional state, method of meditation, and personal physical condition. In this study, we propose a strategy with a cross-sectional analysis to evaluate the meditation experience with 2 artificial intelligence techniques: artificial neural network and support vector machine. Within this analysis system, 3 features of the electroencephalography alpha spectrum and variant normalizing scaling are manipulated as the evaluating variables for the detection of accuracy. Thereafter, by modulating the sliding window (the period of the analyzed data) and shifting interval of the window (the time interval to shift the analyzed data), the effect of immediate analysis for the 2 methods is compared. This analysis system is performed on 3 meditation groups, categorizing their meditation experiences in 10-year intervals from novice to junior and to senior. After an exhausted calculation and cross-validation across all variables, the high accuracy rate >98% is achievable under the criterion of 0.5-minute sliding window and 2 seconds shifting interval for both methods. In a word, the minimum analyzable data length is 0.5 minute and the minimum recognizable temporal resolution is 2 seconds in the decision of meditative classification. Our proposed classifier of the meditation experience promotes a rapid evaluation system to distinguish meditation experience and a beneficial utilization of artificial techniques for the big-data analysis. PMID:28422856

Tyre-road contact using a particle-envelope surface model

NASA Astrophysics Data System (ADS)

Pinnington, Roger J.

2013-12-01

Determination of the contact forces is the central problem in all aspects of road-tyre interaction: i.e. noise, energy loss and friction. A procedure to find the contact forces under a rolling tyre is presented in four stages. First, the contact stiffness of a uniform peak array from indentations in the rubber tread, and also tyre carcass deflection, is described by some new simplified expressions. Second, a routine divides a single surface profile into equal search intervals, in which the highest peaks are identified. These are used to obtain the parameters for the interval, i.e. the mean envelope and the mean interval. The process is repeated at geometrically decreasing search intervals until the level of the data resolution, thereby describing the profile by a set of envelopes. The ‘strip profile’ ultimately used to describe the surface, is obtained by selecting the highest points across the profiles of one stone's width. The third stage is to combine the strip profile envelopes with the contact stiffness expressions, yielding the nonlinear stiffness-displacement, and force-displacement relationships for the chosen road-tyre combination. Finally the contact pressure distribution from a steady-state rolling tyre model is applied to the strip profile, via the force-displacement relationship, giving the local tyre displacements on the road texture. This displacement pattern is shown to be proportional to the time and space varying contact pressure, which then is incorporated into a wave equation for rolling contact.

The Application of Root Mean Square Electrocardiography (RMS ECG) for the Detection of Acquired and Congenital Long QT Syndrome

PubMed Central

Lux, Robert L.; Sower, Christopher Todd; Allen, Nancy; Etheridge, Susan P.; Tristani-Firouzi, Martin; Saarel, Elizabeth V.

2014-01-01

Background Precise measurement of the QT interval is often hampered by difficulty determining the end of the low amplitude T wave. Root mean square electrocardiography (RMS ECG) provides a novel alternative measure of ventricular repolarization. Experimental data have shown that the interval between the RMS ECG QRS and T wave peaks (RTPK) closely reflects the mean ventricular action potential duration while the RMS T wave width (TW) tracks the dispersion of repolarization timing. Here, we tested the precision of RMS ECG to assess ventricular repolarization in humans in the setting of drug-induced and congenital Long QT Syndrome (LQTS). Methods RMS ECG signals were derived from high-resolution 24 hour Holter monitor recordings from 68 subjects after receiving placebo and moxifloxacin and from standard 12 lead ECGs obtained in 97 subjects with LQTS and 97 age- and sex-matched controls. RTPK, QTRMS and RMS TW intervals were automatically measured using custom software and compared to traditional QT measures using lead II. Results All measures of repolarization were prolonged during moxifloxacin administration and in LQTS subjects, but the variance of RMS intervals was significantly smaller than traditional lead II measurements. TW was prolonged during moxifloxacin and in subjects with LQT-2, but not LQT-1 or LQT-3. Conclusion These data validate the application of RMS ECG for the detection of drug-induced and congenital LQTS. RMS ECG measurements are more precise than the current standard of care lead II measurements. PMID:24454918

The application of root mean square electrocardiography (RMS ECG) for the detection of acquired and congenital long QT syndrome.

PubMed

Lux, Robert L; Sower, Christopher Todd; Allen, Nancy; Etheridge, Susan P; Tristani-Firouzi, Martin; Saarel, Elizabeth V

2014-01-01

Precise measurement of the QT interval is often hampered by difficulty determining the end of the low amplitude T wave. Root mean square electrocardiography (RMS ECG) provides a novel alternative measure of ventricular repolarization. Experimental data have shown that the interval between the RMS ECG QRS and T wave peaks (RTPK) closely reflects the mean ventricular action potential duration while the RMS T wave width (TW) tracks the dispersion of repolarization timing. Here, we tested the precision of RMS ECG to assess ventricular repolarization in humans in the setting of drug-induced and congenital Long QT Syndrome (LQTS). RMS ECG signals were derived from high-resolution 24 hour Holter monitor recordings from 68 subjects after receiving placebo and moxifloxacin and from standard 12 lead ECGs obtained in 97 subjects with LQTS and 97 age- and sex-matched controls. RTPK, QTRMS and RMS TW intervals were automatically measured using custom software and compared to traditional QT measures using lead II. All measures of repolarization were prolonged during moxifloxacin administration and in LQTS subjects, but the variance of RMS intervals was significantly smaller than traditional lead II measurements. TW was prolonged during moxifloxacin and in subjects with LQT-2, but not LQT-1 or LQT-3. These data validate the application of RMS ECG for the detection of drug-induced and congenital LQTS. RMS ECG measurements are more precise than the current standard of care lead II measurements.

A cross-sectional evaluation of meditation experience on electroencephalography data by artificial neural network and support vector machine classifiers.

PubMed

Lee, Yu-Hao; Hsieh, Ya-Ju; Shiah, Yung-Jong; Lin, Yu-Huei; Chen, Chiao-Yun; Tyan, Yu-Chang; GengQiu, JiaCheng; Hsu, Chung-Yao; Chen, Sharon Chia-Ju

2017-04-01

To quantitate the meditation experience is a subjective and complex issue because it is confounded by many factors such as emotional state, method of meditation, and personal physical condition. In this study, we propose a strategy with a cross-sectional analysis to evaluate the meditation experience with 2 artificial intelligence techniques: artificial neural network and support vector machine. Within this analysis system, 3 features of the electroencephalography alpha spectrum and variant normalizing scaling are manipulated as the evaluating variables for the detection of accuracy. Thereafter, by modulating the sliding window (the period of the analyzed data) and shifting interval of the window (the time interval to shift the analyzed data), the effect of immediate analysis for the 2 methods is compared. This analysis system is performed on 3 meditation groups, categorizing their meditation experiences in 10-year intervals from novice to junior and to senior. After an exhausted calculation and cross-validation across all variables, the high accuracy rate >98% is achievable under the criterion of 0.5-minute sliding window and 2 seconds shifting interval for both methods. In a word, the minimum analyzable data length is 0.5 minute and the minimum recognizable temporal resolution is 2 seconds in the decision of meditative classification. Our proposed classifier of the meditation experience promotes a rapid evaluation system to distinguish meditation experience and a beneficial utilization of artificial techniques for the big-data analysis.

Reconstructing Southern Greenland Ice Sheet History During the Plio-Pleistocene Intensification of Northern Hemisphere Glaciation: Insights from IODP Site U1307

NASA Astrophysics Data System (ADS)

Blake-Mizen, K. R.; Hatfield, R. G.; Carlson, A. E.; Walczak, M. H.; Stoner, J. S.; Xuan, C.; Lawrence, K. T.; Bailey, I.

2017-12-01

Should it melt entirely, the Greenland Ice Sheet (GrIS) has the potential to raise global sea-level by 7 metres. With the Arctic continuing to warm at a remarkable rate, to better understand how the GrIS will respond to future anthropogenically-induced climate change we must constrain its natural variability in the geological past. In this regard, much uncertainty exists surrounding its pre-Quaternary history; particularly during the mid-Piacenzian warm period (mPWP; 3.3-3.0 Ma) - widely considered an analogue for near-future equilibrium climate with modern atmospheric CO2 levels and elevated temperatures relative to today - and the late Pliocene/early Pleistocene onset of widespread Northern Hemisphere glaciation (NHG, 2.7 Ma). GrIS reconstructions for these intervals have been largely hampered by a lack of well-dated, high-resolution records from suitable sites. To address this, we present new high-resolution, multi-proxy records from IODP Site U1307, a North Atlantic marine sediment core recovered from the Eirik Drift just south of Greenland. Generation of a new high-resolution relative palaeointensity (RPI)-based age-model - representing the first of its kind for high-latitude sediments deposited during NHG - has enabled strong orbital age control. Our ice-rafted debris (IRD) record confirms a 2.72 Ma initiation of major southern GrIS marine-terminating glaciations, which appear to persist even through interglacial periods up to at least 2.24 Ma. XRF-scanning and IRD evidence suggests, however, that an ephemeral ice-cap of likely considerable size persisted on southern Greenland prior to the mPWP. These data, together with the analysed provenance of individual IRD, indicate marine-based GrIS margins extended southward over the NHG interval and only occurred on Greenland's southern tip from 2.7 Ma. Despite a large increase in the deposition of GrIS-derived IRD from this time, bulk sedimentation rates and magnetic grain-size dropped significantly, implying that the onset of NHG 2.7 Ma was associated with a change in the strength and/or depth of the Western Boundary Undercurrent at the site. IODP Site U1307 therefore provides a unique opportunity to constrain southern GrIS behaviour and deep-ocean response during these key climatic intervals, lending valuable lessons to future predictions.

Lithostratigraphy and microfacies analyses of the Lateglacial and early Holocene sediment record from Lake Haemelsee (Germany)

NASA Astrophysics Data System (ADS)

Haliuc, Aritina; Brauer, Achim; Dulski, Peter; Engels, Stefan; Lane, Christine

2015-04-01

Annually laminated sediments are unique continental archives holding essential paleoenvironmental and paleoclimatic information providing the opportunity (i) to evaluate the climate variability at inter-annual to decadal scale and (ii) to construct independent and reliable chronologies. Lake Haemelsee in northern Germany (19.5 m a.s.l) is a key site for tracing high-resolution climatic and environmental evolution in W Europe because of its partly varved sediments. Here, we apply lithostratigraphical, geochemical and micro-facies analyses for the bottom sediments (~1700 to 1300 cm sediment depth) in order to investigate the driving mechanisms, timing and amplitude of Lateglacial abrupt climate changes to the onset of the Holocene warming. Detailed investigation includes micro-facies analyses on petrographic thin sections combined with high-resolution µ-XRF element scanning on both fresh sediment core halves (200 µm resolution) and impregnated sediment blocks (50µm resolution). Based on these analyses, the sediment composite profile (378 cm) has been divided in ten lithozones, each exhibiting different sedimentation modes in response to regional and local climatic and environmental changes. Micro-facies analyses revealed that sediments consist of organic matter, siderite, calcite, clay/silt and sand. The basal sediments consist of glacio-fluvial material. Fine laminations are best preserved in lithozone 5 (1522-1573 cm), where minima in element proxies for detrital sediments (Ti, K, Si) and maxima in Fe and Mn indicate the prevalence of anoxic meromictic conditions. Three different varve facies types were distinguished: i) the clastic-organic varves are specific for the intervals 1571-1573 cm and 1536-1541 cm; ii) calcite/siderite-organic varves appear between 1568-1571 and 1541-1545 cm; iii) the siderite-organic varves are characteristic for the middle of the lithozone 5 spanning from 1545-1568 cm. These changes in varve facies reflect the complex answer of sedimentary conditions to climatic changes during Allerød and Allerød/Younger Dryas transition. An increased detrital sediment flux characterizes lithozone 6 and, most probably reflects the Younger Dryas cold interval. This interpretation is supported by the late Allerød Laacher See Tephra, an important chronostratigraphic marker horizon to link the floating 625 varve year chronology for the Allerød interstadial to an absolute time scale. Also, the preliminary pollen data provided the biostratigraphical information for establishing the lateglacial boundaries. Poorly preserved organic laminas are characteristic for lithozone 7 (1445-1474 cm). Our preliminary results demonstrate that the lake system responded sensitively to rapid and short-term climatic changes and these responses are well-expressed in sedimentological and geochemical variability.

Weather extremes and the Romans - A marine palynological perspective on Italian temperature and precipitation between 200 BC and 500 AD

NASA Astrophysics Data System (ADS)

Zonneveld, Karin; Clotten, Caroline; Chen, Liang

2015-04-01

Sediments of a tephra-dated marine sediment core located at the distal part of the Po-river discharge plume (southern Italy) have been studied with a three annual resolution. Based on the variability in the dinoflagellate cyst content detailed reconstructions have been established of variability in precipitation related river discharge rates and local air temperature. Furthermore about the variability in distort water quality has been reconstructed. We show that both precipitation and temperature signals vary in tune with cyclic changes in solar insolation. On top of these cyclic changes, short term extremes in temperature and precipitation can be observed that can be interpreted to reflect periods of local weather extremes. Comparison of our reconstructions with historical information suggest that times of high temperatures and maximal precipitation corresponds to the period of maximal expansion of the Roman Empire. We have strong indications that at this time discharge waters might have contained higher nutrient concentrations compared to previous and later time intervals suggesting anthropogenic influence of the water quality. First pilot-results suggest that the decrease in temperature reconstructed just after the "Roman Optimum" corresponds to an increase in numbers of armored conflicts between the Roman and German cultures. Furthermore we observe a resemblance in timing of short-term intervals with cold weather spells during the early so called "Dark-Age-Period" to correspond to epidemic/pandemic events in Europe.

Satellite Remote Sensing for Developing Time and Space Resolved Estimates of Ambient Particulate in Cleveland, OH.

PubMed

Kumar, Naresh; Chu, Allen D; Foster, Andrew D; Peters, Thomas; Willis, Robert

2011-09-01

This article empirically demonstrates the use of fine resolution satellite-based aerosol optical depth (AOD) to develop time and space resolved estimates of ambient particulate matter (PM) ≤2.5 µm and ≤10 µm in aerodynamic diameters (PM(2.5) and PM(10), respectively). AOD was computed at three different spatial resolutions, i.e., 2 km (means 2 km × 2 km area at nadir), 5 km, and 10 km, by using the data from MODerate Resolution Imaging Spectroradiometer (MODIS), aboard the Terra and Aqua satellites. Multiresolution AOD from MODIS (AOD(MODIS)) was compared with the in situ measurements of AOD by NASA's AErosol RObotic NETwork (AERONET) sunphotometer (AOD(AERONET)) at Bondville, IL, to demonstrate the advantages of the fine resolution AOD(MODIS) over the 10-km AOD(MODIS), especially for air quality prediction. An instrumental regression that corrects AOD(MODIS) for meteorological conditions was used for developing a PM predictive model.The 2-km AOD(MODIS) aggregated within 0.025° and 15-min intervals shows the best association with the in situ measurements of AOD(AERONET). The 2-km AOD(MODIS) seems more promising to estimate time and space resolved estimates of ambient PM than the 10-km AOD(MODIS), because of better location precision and a significantly greater number of data points across geographic space and time. Utilizing the collocated AOD(MODIS) and PM data in Cleveland, OH, a regression model was developed for predicting PM for all AOD(MODIS) data points. Our analysis suggests that the slope of the 2-km AOD(MODIS) (instrumented on meteorological conditions) is close to unity with the PM monitored on the ground. These results should be interpreted with caution, because the slope of AOD(MODIS) ranges from 0.52 to 1.72 in the site-specific models. In the cross validation of the overall model, the root mean square error (RMSE) of PM(10) was smaller (2.04 µg/m(3) in overall model) than that of PM(2.5) (2.5 µg/m(3)). The predicted PM in the AOD(MODIS) data (∼2.34 million data points) was utilized to develop a systematic grid of daily PM at 5-km spatial resolution with the aid of spatiotemporal Kriging.

Satellite Remote Sensing for Developing Time and Space Resolved Estimates of Ambient Particulate in Cleveland, OH

PubMed Central

Kumar, Naresh; Chu, Allen D.; Foster, Andrew D.; Peters, Thomas; Willis, Robert

2011-01-01

This article empirically demonstrates the use of fine resolution satellite-based aerosol optical depth (AOD) to develop time and space resolved estimates of ambient particulate matter (PM) ≤2.5 µm and ≤10 µm in aerodynamic diameters (PM2.5 and PM10, respectively). AOD was computed at three different spatial resolutions, i.e., 2 km (means 2 km × 2 km area at nadir), 5 km, and 10 km, by using the data from MODerate Resolution Imaging Spectroradiometer (MODIS), aboard the Terra and Aqua satellites. Multiresolution AOD from MODIS (AODMODIS) was compared with the in situ measurements of AOD by NASA’s AErosol RObotic NETwork (AERONET) sunphotometer (AODAERONET) at Bondville, IL, to demonstrate the advantages of the fine resolution AODMODIS over the 10-km AODMODIS, especially for air quality prediction. An instrumental regression that corrects AODMODIS for meteorological conditions was used for developing a PM predictive model. The 2-km AODMODIS aggregated within 0.025° and 15-min intervals shows the best association with the in situ measurements of AODAERONET. The 2-km AODMODIS seems more promising to estimate time and space resolved estimates of ambient PM than the 10-km AODMODIS, because of better location precision and a significantly greater number of data points across geographic space and time. Utilizing the collocated AODMODIS and PM data in Cleveland, OH, a regression model was developed for predicting PM for all AODMODIS data points. Our analysis suggests that the slope of the 2-km AODMODIS (instrumented on meteorological conditions) is close to unity with the PM monitored on the ground. These results should be interpreted with caution, because the slope of AODMODIS ranges from 0.52 to 1.72 in the site-specific models. In the cross validation of the overall model, the root mean square error (RMSE) of PM10 was smaller (2.04 µg/m3 in overall model) than that of PM2.5 (2.5 µg/m3). The predicted PM in the AODMODIS data (∼2.34 million data points) was utilized to develop a systematic grid of daily PM at 5-km spatial resolution with the aid of spatiotemporal Kriging. PMID:22238503

Rapid ambiguity resolution over medium-to-long baselines based on GPS/BDS multi-frequency observables

NASA Astrophysics Data System (ADS)

Gong, Xiaopeng; Lou, Yidong; Liu, Wanke; Zheng, Fu; Gu, Shengfeng; Wang, Hua

2017-02-01

Medium-long baseline RTK positioning generally needs a long initial time to find an accurate position due to non-negligible atmospheric delay residual. In order to shorten the initial or re-convergence time, a rapid phase ambiguity resolution method is employed based on GPS/BDS multi-frequency observables in this paper. This method is realized by two steps. First, double-differenced un-combined observables (i.e., L1/L2 and B1/B2/B3 observables) are used to obtain a float solution with atmospheric delay estimated as random walk parameter by using Kalman filter. This model enables an easy and consistent implementation for different systems and different frequency observables and can readily be extended to use more satellite navigation systems (e.g., Galileo, QZSS). Additional prior constraints for atmospheric information can be quickly added as well, because atmospheric delay is parameterized. Second, in order to fix ambiguity rapidly and reliably, ambiguities are divided into three types (extra-wide-lane (EWL), wide-lane (WL) and narrow-lane (NL)) according to their wavelengths and are to be fixed sequentially by using the LAMBDA method. Several baselines ranging from 61 km to 232 km collected by Trimble and Panda receivers are used to validate the method. The results illustrate that it only takes approximately 1, 2 and 6 epochs (30 s intervals) to fix EWL, WL and NL ambiguities, respectively. More epochs' observables are needed to fix WL and NL ambiguity around local time 14:00 than other time mainly due to more active ionosphere activity. As for the re-convergence time, the simulated results show that 90% of epochs can be fixed within 2 epochs by using prior atmospheric delay information obtained from previously 5 min. Finally, as for positioning accuracy, meter, decimeter and centimeter level positioning results are obtained according to different ambiguity resolution performances, i.e., EWL, WL and NL fixed solutions.

Ecological and sampling constraints on defining landscape fire severity

USGS Publications Warehouse

Key, C.H.

2006-01-01

Ecological definition and detection of fire severity are influenced by factors of spatial resolution and timing. Resolution determines the aggregation of effects within a sampling unit or pixel (alpha variation), hence limiting the discernible ecological responses, and controlling the spatial patchiness of responses distributed throughout a burn (beta variation). As resolution decreases, alpha variation increases, extracting beta variation and complexity from the spatial model of the whole burn. Seasonal timing impacts the quality of radiometric data in terms of transmittance, sun angle, and potential contrast between responses within burns. Detection sensitivity candegrade toward the end of many fire seasons when low sun angles, vegetation senescence, incomplete burning, hazy conditions, or snow are common. Thus, a need exists to supersede many rapid response applications when remote sensing conditions improve. Lag timing, or timesince fire, notably shapes the ecological character of severity through first-order effects that only emerge with time after fire, including delayed survivorship and mortality. Survivorship diminishes the detected magnitude of severity, as burned vegetation remains viable and resprouts, though at first it may appear completely charred or consumed above ground. Conversely, delayed mortality increases the severity estimate when apparently healthy vegetation is in fact damaged by heat to the extent that it dies over time. Both responses dependon fire behavior and various species-specific adaptations to fire that are unique to the pre-firecomposition of each burned area. Both responses can lead initially to either over- or underestimating severity. Based on such implications, three sampling intervals for short-term burn severity are identified; rapid, initial, and extended assessment, sampled within about two weeks, two months, and depending on the ecotype, from three months to one year after fire, respectively. Spatial and temporal conditions of sampling strategies constrain data quality and ecological information obtained about fire severity. Though commonly overlooked, such considerations determine the objectives and hypotheses that are appropriate for each application, and are especially important when building comparative studies or long-term reference databases on fire severity.

Atlas of stratospheric submillimeter lines. I - The 7-20 kayser interval

NASA Technical Reports Server (NTRS)

Baldecchi, M. G.; Carli, B.; Mencaraglia, F.; Bonetti, A.; Carlotti, M.

1984-01-01

The stratospheric emission in the submillimeter spectral region has been measured from 38.2 km altitude with a resolution of 0.0033 kayser. In most cases this resolution makes possible the separation of contributions caused by the individual rotational transitions. An atlas of the observed features is given as a guide to both the measurements of minor stratospheric constituents concentration and the evaluation of stratospheric transparency for the measurement of nontelluric sources.

Global Data for Ecology and Epidemiology: A Novel Algorithm for Temporal Fourier Processing MODIS Data

PubMed Central

Scharlemann, Jörn P. W.; Benz, David; Hay, Simon I.; Purse, Bethan V.; Tatem, Andrew J.; Wint, G. R. William; Rogers, David J.

2008-01-01

Background Remotely-sensed environmental data from earth-orbiting satellites are increasingly used to model the distribution and abundance of both plant and animal species, especially those of economic or conservation importance. Time series of data from the MODerate-resolution Imaging Spectroradiometer (MODIS) sensors on-board NASA's Terra and Aqua satellites offer the potential to capture environmental thermal and vegetation seasonality, through temporal Fourier analysis, more accurately than was previously possible using the NOAA Advanced Very High Resolution Radiometer (AVHRR) sensor data. MODIS data are composited over 8- or 16-day time intervals that pose unique problems for temporal Fourier analysis. Applying standard techniques to MODIS data can introduce errors of up to 30% in the estimation of the amplitudes and phases of the Fourier harmonics. Methodology/Principal Findings We present a novel spline-based algorithm that overcomes the processing problems of composited MODIS data. The algorithm is tested on artificial data generated using randomly selected values of both amplitudes and phases, and provides an accurate estimate of the input variables under all conditions. The algorithm was then applied to produce layers that capture the seasonality in MODIS data for the period from 2001 to 2005. Conclusions/Significance Global temporal Fourier processed images of 1 km MODIS data for Middle Infrared Reflectance, day- and night-time Land Surface Temperature (LST), Normalised Difference Vegetation Index (NDVI), and Enhanced Vegetation Index (EVI) are presented for ecological and epidemiological applications. The finer spatial and temporal resolution, combined with the greater geolocational and spectral accuracy of the MODIS instruments, compared with previous multi-temporal data sets, mean that these data may be used with greater confidence in species' distribution modelling. PMID:18183289

Global data for ecology and epidemiology: a novel algorithm for temporal Fourier processing MODIS data.

PubMed

Scharlemann, Jörn P W; Benz, David; Hay, Simon I; Purse, Bethan V; Tatem, Andrew J; Wint, G R William; Rogers, David J

2008-01-09

Remotely-sensed environmental data from earth-orbiting satellites are increasingly used to model the distribution and abundance of both plant and animal species, especially those of economic or conservation importance. Time series of data from the MODerate-resolution Imaging Spectroradiometer (MODIS) sensors on-board NASA's Terra and Aqua satellites offer the potential to capture environmental thermal and vegetation seasonality, through temporal Fourier analysis, more accurately than was previously possible using the NOAA Advanced Very High Resolution Radiometer (AVHRR) sensor data. MODIS data are composited over 8- or 16-day time intervals that pose unique problems for temporal Fourier analysis. Applying standard techniques to MODIS data can introduce errors of up to 30% in the estimation of the amplitudes and phases of the Fourier harmonics. We present a novel spline-based algorithm that overcomes the processing problems of composited MODIS data. The algorithm is tested on artificial data generated using randomly selected values of both amplitudes and phases, and provides an accurate estimate of the input variables under all conditions. The algorithm was then applied to produce layers that capture the seasonality in MODIS data for the period from 2001 to 2005. Global temporal Fourier processed images of 1 km MODIS data for Middle Infrared Reflectance, day- and night-time Land Surface Temperature (LST), Normalised Difference Vegetation Index (NDVI), and Enhanced Vegetation Index (EVI) are presented for ecological and epidemiological applications. The finer spatial and temporal resolution, combined with the greater geolocational and spectral accuracy of the MODIS instruments, compared with previous multi-temporal data sets, mean that these data may be used with greater confidence in species' distribution modelling.

Effects of sampling interval on spatial patterns and statistics of watershed nitrogen concentration

USGS Publications Warehouse

Wu, S.-S.D.; Usery, E.L.; Finn, M.P.; Bosch, D.D.

2009-01-01

This study investigates how spatial patterns and statistics of a 30 m resolution, model-simulated, watershed nitrogen concentration surface change with sampling intervals from 30 m to 600 m for every 30 m increase for the Little River Watershed (Georgia, USA). The results indicate that the mean, standard deviation, and variogram sills do not have consistent trends with increasing sampling intervals, whereas the variogram ranges remain constant. A sampling interval smaller than or equal to 90 m is necessary to build a representative variogram. The interpolation accuracy, clustering level, and total hot spot areas show decreasing trends approximating a logarithmic function. The trends correspond to the nitrogen variogram and start to level at a sampling interval of 360 m, which is therefore regarded as a critical spatial scale of the Little River Watershed. Copyright ?? 2009 by Bellwether Publishing, Ltd. All right reserved.

Towards High Spa-Temporal Resolution Estimates of Surface Radiative Fluxes from Geostationary Satellite Observations for the Tibetan Plateau

NASA Astrophysics Data System (ADS)

Niu, X.; Yang, K.; Tang, W.; Qin, J.

2014-12-01

Surface Solar Radiation (SSR) plays an important role of the hydrological and land process modeling, which particularly contributes more than 90% to the total melt energy for the Tibetan Plateau (TP) ice melting. Neither surface measurement nor existing remote sensing products can meet that requirement in TP. The well-known satellite products (i.e. ISCCP-FD and GEWEX-SRB) are in relatively low spatial resolution (0.5º-2.5º) and temporal resolution (3-hourly, daily, or monthly). The objective of this study is to develop capabilities to improved estimates of SSR in TP based on geostationary satellite observations from the Multi-functional Transport Satellite (MTSAT) with high spatial (0.05º) and temporal (hourly) resolution. An existing physical model, the UMD-SRB (University of Maryland Surface Radiation Budget) which is the basis of the GEWEX-SRB model, is re-visited to improve SSR estimates in TP. The UMD-SRB algorithm transforms TOA radiances into broadband albedos in order to infer atmospheric transmissivity which finally determines the SSR. Specifically, main updates introduced in this study are: implementation at 0.05º spatial resolution at hourly intervals integrated to daily and monthly time scales; and improvement of surface albedo model by introducing the most recently developed Global Land Surface Broadband Albedo Product (GLASS) based on MODIS data. This updated inference scheme will be evaluated against ground observations from China Meteorological Administration (CMA) radiation stations and three TP radiation stations contributed from the Institute of Tibetan Plateau Research.

On the approach to Mott's transition in glass-ceramic nanocomposite due to heat treatment

NASA Astrophysics Data System (ADS)

Mahdy, Iman A.; Heikal, Sh.; Abd-Rabo, A. S.; Abdel Ghany, A.; Bahgat, A. A.

2015-07-01

In the present work, the glass-ceramic nanocomposite (GCNC) of the composition 30[0.75 BaTiO3+0.25 PbTiO3]+70 V2O5 (mol. %) was prepared from the parent glass by isothermal heat treatment (HT) at 723 K for different time intervals 0.25, 0.5, 1.5, 2, and 2.5 h, respectively. The bulk density and some related parameters were calculated. X-ray diffraction and Hi-Resolution Transmission Electron Microscope (HRTEM) were used to identify different phases as well as particle size of the precipitated nanocrystals during the heat treatment process. The DC electrical conductivity was enhanced three orders of magnitudes (3×103) by increasing HT time. The resistivity measurements on the other hand as a function of time show an approach to nonmetallic-metallic transition for the prepared NCGC samples. Mott's VRH conduction mechanism was predicted as a result of the increase of the heat treatment time.

Short-Term Forecasting of Taiwanese Earthquakes Using a Universal Model of Fusion-Fission Processes

PubMed Central

Cheong, Siew Ann; Tan, Teck Liang; Chen, Chien-Chih; Chang, Wu-Lung; Liu, Zheng; Chew, Lock Yue; Sloot, Peter M. A.; Johnson, Neil F.

2014-01-01

Predicting how large an earthquake can be, where and when it will strike remains an elusive goal in spite of the ever-increasing volume of data collected by earth scientists. In this paper, we introduce a universal model of fusion-fission processes that can be used to predict earthquakes starting from catalog data. We show how the equilibrium dynamics of this model very naturally explains the Gutenberg-Richter law. Using the high-resolution earthquake catalog of Taiwan between Jan 1994 and Feb 2009, we illustrate how out-of-equilibrium spatio-temporal signatures in the time interval between earthquakes and the integrated energy released by earthquakes can be used to reliably determine the times, magnitudes, and locations of large earthquakes, as well as the maximum numbers of large aftershocks that would follow. PMID:24406467

The confidence-accuracy relationship for eyewitness identification decisions: Effects of exposure duration, retention interval, and divided attention.

PubMed

Palmer, Matthew A; Brewer, Neil; Weber, Nathan; Nagesh, Ambika

2013-03-01

Prior research points to a meaningful confidence-accuracy (CA) relationship for positive identification decisions. However, there are theoretical grounds for expecting that different aspects of the CA relationship (calibration, resolution, and over/underconfidence) might be undermined in some circumstances. This research investigated whether the CA relationship for eyewitness identification decisions is affected by three, forensically relevant variables: exposure duration, retention interval, and divided attention at encoding. In Study 1 (N = 986), a field experiment, we examined the effects of exposure duration (5 s vs. 90 s) and retention interval (immediate testing vs. a 1-week delay) on the CA relationship. In Study 2 (N = 502), we examined the effects of attention during encoding on the CA relationship by reanalyzing data from a laboratory experiment in which participants viewed a stimulus video under full or divided attention conditions and then attempted to identify two targets from separate lineups. Across both studies, all three manipulations affected identification accuracy. The central analyses concerned the CA relation for positive identification decisions. For the manipulations of exposure duration and retention interval, overconfidence was greater in the more difficult conditions (shorter exposure; delayed testing) than the easier conditions. Only the exposure duration manipulation influenced resolution (which was better for 5 s than 90 s), and only the retention interval manipulation affected calibration (which was better for immediate testing than delayed testing). In all experimental conditions, accuracy and diagnosticity increased with confidence, particularly at the upper end of the confidence scale. Implications for theory and forensic settings are discussed.

High precision gas hydrate imaging of small-scale and high-resolution marine sparker multichannel seismic data

NASA Astrophysics Data System (ADS)

Luo, D.; Cai, F.

2017-12-01

Small-scale and high-resolution marine sparker multi-channel seismic surveys using large energy sparkers are characterized by a high dominant frequency of the seismic source, wide bandwidth, and a high resolution. The technology with a high-resolution and high-detection precision was designed to improve the imaging quality of shallow sedimentary. In the study, a 20KJ sparker and 24-channel streamer cable with a 6.25m group interval were used as a seismic source and receiver system, respectively. Key factors for seismic imaging of gas hydrate are enhancement of S/N ratio, amplitude compensation and detailed velocity analysis. However, the data in this study has some characteristics below: 1. Small maximum offsets are adverse to velocity analysis and multiple attenuation. 2. Lack of low frequency information, that is, information less than 100Hz are invisible. 3. Low S/N ratio since less coverage times (only 12 times). These characteristics make it difficult to reach the targets of seismic imaging. In the study, the target processing methods are used to improve the seismic imaging quality of gas hydrate. First, some technologies of noise suppression are combined used in pre-stack seismic data to suppression of seismic noise and improve the S/N ratio. These technologies including a spectrum sharing noise elimination method, median filtering and exogenous interference suppression method. Second, the combined method of three technologies including SRME, τ-p deconvolution and high precision Radon transformation is used to remove multiples. Third, accurate velocity field are used in amplitude energy compensation to highlight the Bottom Simulating Reflector (short for BSR, the indicator of gas hydrates) and gas migration pathways (such as gas chimneys, hot spots et al.). Fourth, fine velocity analysis technology are used to improve accuracy of velocity analysis. Fifth, pre-stack deconvolution processing technology is used to compensate for low frequency energy and suppress of ghost, thus formation reflection characteristics are highlighted. The result shows that the small-scale and high resolution marine sparker multi-channel seismic surveys are very effective in improving the resolution and quality of gas hydrate imaging than the conventional seismic acquisition technology.

Evaluation of Matrix9 silicon photomultiplier array for small-animal PET.

PubMed

Du, Junwei; Schmall, Jeffrey P; Yang, Yongfeng; Di, Kun; Roncali, Emilie; Mitchell, Gregory S; Buckley, Steve; Jackson, Carl; Cherry, Simon R

2015-02-01

The MatrixSL-9-30035-OEM (Matrix9) from SensL is a large-area silicon photomultiplier (SiPM) photodetector module consisting of a 3 × 3 array of 4 × 4 element SiPM arrays (total of 144 SiPM pixels) and incorporates SensL's front-end electronics board and coincidence board. Each SiPM pixel measures 3.16 × 3.16 mm(2) and the total size of the detector head is 47.8 × 46.3 mm(2). Using 8 × 8 polished LSO/LYSO arrays (pitch 1.5 mm) the performance of this detector system (SiPM array and readout electronics) was evaluated with a view for its eventual use in small-animal positron emission tomography (PET). Measurements of noise, signal, signal-to-noise ratio, energy resolution, flood histogram quality, timing resolution, and array trigger error were obtained at different bias voltages (28.0-32.5 V in 0.5 V intervals) and at different temperatures (5 °C-25 °C in 5 °C degree steps) to find the optimal operating conditions. The best measured signal-to-noise ratio and flood histogram quality for 511 keV gamma photons were obtained at a bias voltage of 30.0 V and a temperature of 5 °C. The energy resolution and timing resolution under these conditions were 14.2% ± 0.1% and 4.2 ± 0.1 ns, respectively. The flood histograms show that all the crystals in the 1.5 mm pitch LSO array can be clearly identified and that smaller crystal pitches can also be resolved. Flood histogram quality was also calculated using different center of gravity based positioning algorithms. Improved and more robust results were achieved using the local 9 pixels for positioning along with an energy offset calibration. To evaluate the front-end detector readout, and multiplexing efficiency, an array trigger error metric is introduced and measured at different lower energy thresholds. Using a lower energy threshold greater than 150 keV effectively eliminates any mispositioning between SiPM arrays. In summary, the Matrix9 detector system can resolve high-resolution scintillator arrays common in small-animal PET with adequate energy resolution and timing resolution over a large detector area. The modular design of the Matrix9 detector allows it to be used as a building block for simple, low channel-count, yet high performance, small animal PET or PET/MRI systems.

Evaluation of Matrix9 silicon photomultiplier array for small-animal PET

PubMed Central

Du, Junwei; Schmall, Jeffrey P.; Yang, Yongfeng; Di, Kun; Roncali, Emilie; Mitchell, Gregory S.; Buckley, Steve; Jackson, Carl; Cherry, Simon R.

2015-01-01

Purpose: The MatrixSL-9-30035-OEM (Matrix9) from SensL is a large-area silicon photomultiplier (SiPM) photodetector module consisting of a 3 × 3 array of 4 × 4 element SiPM arrays (total of 144 SiPM pixels) and incorporates SensL’s front-end electronics board and coincidence board. Each SiPM pixel measures 3.16 × 3.16 mm2 and the total size of the detector head is 47.8 × 46.3 mm2. Using 8 × 8 polished LSO/LYSO arrays (pitch 1.5 mm) the performance of this detector system (SiPM array and readout electronics) was evaluated with a view for its eventual use in small-animal positron emission tomography (PET). Methods: Measurements of noise, signal, signal-to-noise ratio, energy resolution, flood histogram quality, timing resolution, and array trigger error were obtained at different bias voltages (28.0–32.5 V in 0.5 V intervals) and at different temperatures (5 °C–25 °C in 5 °C degree steps) to find the optimal operating conditions. Results: The best measured signal-to-noise ratio and flood histogram quality for 511 keV gamma photons were obtained at a bias voltage of 30.0 V and a temperature of 5 °C. The energy resolution and timing resolution under these conditions were 14.2% ± 0.1% and 4.2 ± 0.1 ns, respectively. The flood histograms show that all the crystals in the 1.5 mm pitch LSO array can be clearly identified and that smaller crystal pitches can also be resolved. Flood histogram quality was also calculated using different center of gravity based positioning algorithms. Improved and more robust results were achieved using the local 9 pixels for positioning along with an energy offset calibration. To evaluate the front-end detector readout, and multiplexing efficiency, an array trigger error metric is introduced and measured at different lower energy thresholds. Using a lower energy threshold greater than 150 keV effectively eliminates any mispositioning between SiPM arrays. Conclusions: In summary, the Matrix9 detector system can resolve high-resolution scintillator arrays common in small-animal PET with adequate energy resolution and timing resolution over a large detector area. The modular design of the Matrix9 detector allows it to be used as a building block for simple, low channel-count, yet high performance, small animal PET or PET/MRI systems. PMID:25652479

Evaluation of Matrix9 silicon photomultiplier array for small-animal PET

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

Du, Junwei, E-mail: jwdu@ucdavis.edu; Schmall, Jeffrey P.; Yang, Yongfeng

Purpose: The MatrixSL-9-30035-OEM (Matrix9) from SensL is a large-area silicon photomultiplier (SiPM) photodetector module consisting of a 3 × 3 array of 4 × 4 element SiPM arrays (total of 144 SiPM pixels) and incorporates SensL’s front-end electronics board and coincidence board. Each SiPM pixel measures 3.16 × 3.16 mm{sup 2} and the total size of the detector head is 47.8 × 46.3 mm{sup 2}. Using 8 × 8 polished LSO/LYSO arrays (pitch 1.5 mm) the performance of this detector system (SiPM array and readout electronics) was evaluated with a view for its eventual use in small-animal positron emission tomographymore » (PET). Methods: Measurements of noise, signal, signal-to-noise ratio, energy resolution, flood histogram quality, timing resolution, and array trigger error were obtained at different bias voltages (28.0–32.5 V in 0.5 V intervals) and at different temperatures (5 °C–25 °C in 5 °C degree steps) to find the optimal operating conditions. Results: The best measured signal-to-noise ratio and flood histogram quality for 511 keV gamma photons were obtained at a bias voltage of 30.0 V and a temperature of 5 °C. The energy resolution and timing resolution under these conditions were 14.2% ± 0.1% and 4.2 ± 0.1 ns, respectively. The flood histograms show that all the crystals in the 1.5 mm pitch LSO array can be clearly identified and that smaller crystal pitches can also be resolved. Flood histogram quality was also calculated using different center of gravity based positioning algorithms. Improved and more robust results were achieved using the local 9 pixels for positioning along with an energy offset calibration. To evaluate the front-end detector readout, and multiplexing efficiency, an array trigger error metric is introduced and measured at different lower energy thresholds. Using a lower energy threshold greater than 150 keV effectively eliminates any mispositioning between SiPM arrays. Conclusions: In summary, the Matrix9 detector system can resolve high-resolution scintillator arrays common in small-animal PET with adequate energy resolution and timing resolution over a large detector area. The modular design of the Matrix9 detector allows it to be used as a building block for simple, low channel-count, yet high performance, small animal PET or PET/MRI systems.« less

Landscape Change Detected Over A 60 Year Period In The Arctic National Wildlife Refuge, Alaska, Using High Resolution Aerial Photographs And Satellite Images

NASA Astrophysics Data System (ADS)

Jorgenson, J. C.; Jorgenson, M. T.; Boldenow, M.; Orndahl, K. M.

2016-12-01

We documented landscape change over a 60 year period in the Arctic National Wildlife Refuge in northeastern Alaska using aerial photographs and satellite images. We used a stratified random sample to allow inference to the whole refuge (78,050 km2), with five random sites in each of seven ecoregions. Each site (2 km2) had a systematic grid of 100 points for a total of 3500 points. We chose study sites in the overlap area covered by acceptable imagery in three time periods: aerial photographs from 1947 - 1955 and 1978 - 1988, Quick Bird and IKONOS satellite images from 2000 - 2007.At each point a 10 meter radius circle was visually evaluated in ARC-MAP for each time period for vegetation type, disturbance, presence of ice wedge polygon microtopography and surface water. A landscape change category was assigned to each point based on differences detected between the three periods. Change types were assigned for time interval 1, interval 2 and overall. Additional explanatory variables included elevation, slope, aspect, geology, physiography and temperature. Overall, 23% of points changed over the study period. Fire was the most common change agent, affecting 28% of the Boreal Forest points. The next most common change was degradation of soil ice wedges (thermokarst), detected at 12% of the points on the North Slope Tundra. The other most common changes included increase in cover of trees or shrubs (7% of Boreal Forest and Brooks Range points) and erosion or deposition on river floodplains and at the Beaufort Sea coast. Changes on the North Slope Tundra tended to be related to landscape wetting, mainly thermokarst. Changes in the Boreal Forest tended to involve landscape drying, including fire, reduced area of lakes and tree increase on wet sites. The second time interval coincided with a shift towards a warmer climate and had greater change in several categories including thermokarst, lake changes and tree and shrub increase.

High definition versus standard definition white light endoscopy for detecting dysplasia in patients with Barrett's esophagus.

PubMed

Sami, S S; Subramanian, V; Butt, W M; Bejkar, G; Coleman, J; Mannath, J; Ragunath, K

2015-01-01

High-definition endoscopy systems provide superior image resolution. The aim of this study was to assess the utility of high definition compared with standard definition endoscopy system for detecting dysplastic lesions in patients with Barrett's esophagus. A retrospective cohort study of patients with non-dysplastic Barrett's esophagus undergoing routine surveillance was performed. Data were retrieved from the central hospital electronic database. Procedures performed for non-surveillance indications, Barrett's esophagus Prague C0M1 classification with no specialized intestinal metaplasia on histology, patients diagnosed with any dysplasia or cancer on index endoscopy, and procedures using advanced imaging techniques were excluded. Logistic regression models were constructed to estimate adjusted odds ratios and 95% confidence intervals comparing outcomes with standard definition and high-definition systems. The high definition was superior to standard definition system in targeted detection of all dysplastic lesions (odds ratio 3.27, 95% confidence interval 1.27-8.40) as well as overall dysplasia detected on both random and target biopsies (odds ratio 2.36, 95% confidence interval 1.50-3.72). More non-dysplastic lesions were detected with the high-definition system (odds ratio 1.16, 95% confidence interval 1.01-1.33). There was no difference between high definition and standard definition endoscopy in the overall (random and target) high-grade dysplasia or cancers detected (odds ratio 0.93, 95% confidence interval 0.83-1.04). Trainee endoscopists, number of biopsies taken, and male sex were all significantly associated with a higher yield for dysplastic lesions. The use of the high-definition endoscopy system is associated with better targeted detection of any dysplasia during routine Barrett's esophagus surveillance. However, high-definition endoscopy cannot replace random biopsies at present time. © 2014 International Society for Diseases of the Esophagus.

The Effects of Limited Intent Information Availability on Self-Separation in Mixed Operations

NASA Technical Reports Server (NTRS)

Lewis, Timothy A.; Phojanamongkolkij, Nipa; Wing, David J.

2012-01-01

This paper presents the results of a computer simulation of the NASA Autonomous Flight Rules (AFR) concept for airborne self-separation in airspace shared with conventional Instrument Flight Rules (IFR) traffic. This study was designed to determine the impact of varying levels of intent information from IFR aircraft on the performance of AFR conflict detection and resolution. The study used Automatic Dependent Surveillance-Broadcast (ADS-B) to supply IFR intent, but other methods such as an uplink from a ground-based System Wide Information Management (SWIM) network could alternatively supply this information. The independent variables of the study consist of the number of ADS-B trajectory change reports broadcast by IFR aircraft and the time interval between those reports. The conflict detection and resolution metrics include: the number of conflicts and losses of separation, the average conflict warning time, and the amount of time spent in strategic vs. tactical flight modes (i.e., whether the autoflight system was decoupled from the planned route in the Flight Management System in order to respond to a short-notice traffic conflict). The results show a measurable benefit of broadcasting IFR intent vs. relying on state-only broadcasts. The results of this study will inform ongoing separation assurance research and FAA NextGen design decisions for the sharing of trajectory intent information in the National Airspace System.

Investigation of water imbibition in porous stone by thermal neutron radiography

NASA Astrophysics Data System (ADS)

Hassanein, R.; Meyer, H. O.; Carminati, A.; Estermann, M.; Lehmann, E.; Vontobel, P.

2006-10-01

The understanding and modelling of the process of water imbibition is important for various applications of physics (e.g. building or soil physics). To measure the spatial distribution of the water content at arbitrary times is not trivial. Neutron radiography provides an appropriate tool for such investigations with excellent time and spatial resolution. Because of the high sensitivity to hydrogen, even small amounts of water in a porous structure can be detected in samples with dimensions up to 40 cm. Three different porous stones found in Indiana, USA, have been investigated (Mansfield sandstone, Salem limestone and Hindustan whetstone). The imbibition of deionized water and a NaCl solution in up- and downwards directions has been tracked during several hours and radiographed at regular intervals. A correction method to reduce the disturbing effects due to neutron scattering is applied. This allows a quantitative evaluation of the water content in addition to the visualization of the water distribution. The results agree well with theoretical models describing water infiltration and reproduce the water content with a pixel resolution of 272 µm in time steps of 1 min. The comparison with the radiographed structure of the dry stone explains variations in the conduction or retention of the water, respectively. The experimental and correction procedures described here can be applied to other porous media and their uptake and loss of fluids.

Digibaro pressure instrument onboard the Phoenix Lander

NASA Astrophysics Data System (ADS)

Harri, A.-M.; Polkko, J.; Kahanpää, H. H.; Schmidt, W.; Genzer, M. M.; Haukka, H.; Savijarv1, H.; Kauhanen, J.

2009-04-01

The Phoenix Lander landed successfully on the Martian northern polar region. The mission is part of the National Aeronautics and Space Administration's (NASA's) Scout program. Pressure observations onboard the Phoenix lander were performed by an FMI (Finnish Meteorological Institute) instrument, based on a silicon diaphragm sensor head manufactured by Vaisala Inc., combined with MDA data processing electronics. The pressure instrument performed successfully throughout the Phoenix mission. The pressure instrument had 3 pressure sensor heads. One of these was the primary sensor head and the other two were used for monitoring the condition of the primary sensor head during the mission. During the mission the primary sensor was read with a sampling interval of 2 s and the other two were read less frequently as a check of instrument health. The pressure sensor system had a real-time data-processing and calibration algorithm that allowed the removal of temperature dependent calibration effects. In the same manner as the temperature sensor, a total of 256 data records (8.53 min) were buffered and they could either be stored at full resolution, or processed to provide mean, standard deviation, maximum and minimum values for storage on the Phoenix Lander's Meteorological (MET) unit.The time constant was approximately 3s due to locational constraints and dust filtering requirements. Using algorithms compensating for the time constant effect the temporal resolution was good enough to detect pressure drops associated with the passage of nearby dust devils.

A framed, 16-image Kirkpatrick–Baez x-ray microscope

DOE PAGES

Marshall, F. J.; Bahr, R. E.; Goncharov, V. N.; ...

2017-09-08

A 16-image Kirkpatrick–Baez (KB)–type x-ray microscope consisting of compact KB mirrors has been assembled for the first time with mirrors aligned to allow it to be coupled to a high-speed framing camera. The high-speed framing camera has four independently gated strips whose emission sampling interval is ~30 ps. Images are arranged four to a strip with ~60-ps temporal spacing between frames on a strip. By spacing the timing of the strips, a frame spacing of ~15 ps is achieved. A framed resolution of ~6-um is achieved with this combination in a 400-um region of laser–plasma x-ray emission in the 2-more » to 8-keV energy range. A principal use of the microscope is to measure the evolution of the implosion stagnation region of cryogenic DT target implosions on the University of Rochester’s OMEGA Laser System. The unprecedented time and spatial resolution achieved with this framed, multi-image KB microscope have made it possible to accurately determine the cryogenic implosion core emission size and shape at the peak of stagnation. In conclusion, these core size measurements, taken in combination with those of ion temperature, neutron-production temporal width, and neutron yield allow for inference of core pressures, currently exceeding 50 GBar in OMEGA cryogenic target implosions.« less

Cellular Telephones Measure Activity and Lifespace in Community-Dwelling Adults: Proof of Principle

PubMed Central

Schenk, Ana Katrin; Witbrodt, Bradley C.; Hoarty, Carrie A.; Carlson, Richard H.; Goulding, Evan H.; Potter, Jane F.; Bonasera, Stephen J.

2011-01-01

OBJECTIVES To describe a system that uses off-the-shelf sensor and telecommunication technologies to continuously measure individual lifespace and activity levels in a novel way. DESIGN Proof of concept involving three field trials of 30, 30, and 21 days. SETTING Omaha, Nebraska, metropolitan and surrounding rural region. PARTICIPANTS Three participants (48-year-old man, 33-year-old woman, and 27-year-old male), none with any functional limitations. MEASUREMENTS Cellular telephones were used to detect in-home position and in-community location and to measure physical activity. Within the home, cellular telephones and Bluetooth transmitters (beacons) were used to locate participants at room-level resolution. Outside the home, the same cellular telephones and global positioning system (GPS) technology were used to locate participants at a community-level resolution. Physical activity was simultaneously measured using the cellular telephone accelerometer. RESULTS This approach had face validity to measure activity and lifespace. More importantly, this system could measure the spatial and temporal organization of these metrics. For example, an individual’s lifespace was automatically calculated across multiple time intervals. Behavioral time budgets showing how people allocate time to specific regions within the home were also automatically generated. CONCLUSION Mobile monitoring shows much promise as an easily deployed system to quantify activity and lifespace, important indicators of function, in community-dwelling adults. PMID:21288235

A framed, 16-image Kirkpatrick–Baez x-ray microscope

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

Marshall, F. J.; Bahr, R. E.; Goncharov, V. N.

A 16-image Kirkpatrick–Baez (KB)–type x-ray microscope consisting of compact KB mirrors has been assembled for the first time with mirrors aligned to allow it to be coupled to a high-speed framing camera. The high-speed framing camera has four independently gated strips whose emission sampling interval is ~30 ps. Images are arranged four to a strip with ~60-ps temporal spacing between frames on a strip. By spacing the timing of the strips, a frame spacing of ~15 ps is achieved. A framed resolution of ~6-um is achieved with this combination in a 400-um region of laser–plasma x-ray emission in the 2-more » to 8-keV energy range. A principal use of the microscope is to measure the evolution of the implosion stagnation region of cryogenic DT target implosions on the University of Rochester’s OMEGA Laser System. The unprecedented time and spatial resolution achieved with this framed, multi-image KB microscope have made it possible to accurately determine the cryogenic implosion core emission size and shape at the peak of stagnation. In conclusion, these core size measurements, taken in combination with those of ion temperature, neutron-production temporal width, and neutron yield allow for inference of core pressures, currently exceeding 50 GBar in OMEGA cryogenic target implosions.« less

Estimation of Rainfall Sampling Uncertainty: A Comparison of Two Diverse Approaches

NASA Technical Reports Server (NTRS)

Steiner, Matthias; Zhang, Yu; Baeck, Mary Lynn; Wood, Eric F.; Smith, James A.; Bell, Thomas L.; Lau, William K. M. (Technical Monitor)

2002-01-01

The spatial and temporal intermittence of rainfall causes the averages of satellite observations of rain rate to differ from the "true" average rain rate over any given area and time period, even if the satellite observations are perfectly accurate. The difference of satellite averages based on occasional observation by satellite systems and the continuous-time average of rain rate is referred to as sampling error. In this study, rms sampling error estimates are obtained for average rain rates over boxes 100 km, 200 km, and 500 km on a side, for averaging periods of 1 day, 5 days, and 30 days. The study uses a multi-year, merged radar data product provided by Weather Services International Corp. at a resolution of 2 km in space and 15 min in time, over an area of the central U.S. extending from 35N to 45N in latitude and 100W to 80W in longitude. The intervals between satellite observations are assumed to be equal, and similar In size to what present and future satellite systems are able to provide (from 1 h to 12 h). The sampling error estimates are obtained using a resampling method called "resampling by shifts," and are compared to sampling error estimates proposed by Bell based on earlier work by Laughlin. The resampling estimates are found to scale with areal size and time period as the theory predicts. The dependence on average rain rate and time interval between observations is also similar to what the simple theory suggests.

Resolving the age of Wilson Creek Formation tephras and the Mono Lake excursion using high-resolution SIMS dating of allanite and zircon rims

NASA Astrophysics Data System (ADS)

Vazquez, J. A.; Lidzbarski, M. I.

2012-12-01

Sediments of the Wilson Creek Formation surrounding Mono Lake preserve a high-resolution archive of glacial and pluvial responses along the eastern Sierra Nevada due to late Pleistocene climate change. An absolute chronology for the Wilson Creek stratigraphy is critical for correlating the paleoclimate record to other archives in the western U.S. and the North Atlantic region. However, multiple attempts to date the Wilson Creek stratigraphy using carbonates and interbedded rhyolitic tephras yield discordant 14C and 40Ar/39Ar results due to open-system effects, carbon reservoir uncertainties, as well as abundant xenocrysts entrained during eruption. Ion microprobe (SIMS) 238U-230Th dating of the final increments of crystallization recorded by allanite and zircon autocrysts from juvenile pyroclasts yields ages that effectively date eruption of key tephra beds and resolve age uncertainties about the Wilson Creek stratigraphy. To date the final several micrometers of crystal growth, individual allanite and zircon crystals were embedded in soft indium to allow sampling of unpolished rims. Isochron ages derived from rims on coexisting allanite and zircon (± glass) from hand-selected pumiceous pyroclasts delimit the timing of Wilson Creek sedimentation between Ashes 7 and 19 (numbering of Lajoie, 1968) to the interval between ca. 27 to ca. 62 ka. The interiors of individual allanite and zircon crystals sectioned in standard SIMS mounts yield model 238U-230Th ages that are mostly <10 k.y. older than their corresponding rim age, suggesting a relatively brief interval of allanite + zircon crystallization before eruption. A minority of allanite and zircon crystals yield rim and interior model ages of ca. 90-100 ka, and are likely to be antecrysts recycled from relatively early Mono Craters volcanism and/or intrusions. Tephra (Ash 15) erupted during the geomagnetic excursion originally designated the Mono Lake excursion yields a rim isochron age of ca. 41 ka indicating that the recorded event is instead the Laschamp excursion. The results are consistent with a depositional chronology from correlation of relative paleointensity (Zimmerman et al., 2006) that indicates quasi-synchronous glacial and hydrologic responses in the Sierra Nevada and Mono Basin to climate change, with intervals of lake filling and glacial-snowpack melting that are in phase with peaks in spring insolation. Moreover, the results demonstrate that high-spatial resolution SIMS dating of accessory mineral rims is an alternative and promising approach for resolving the depositional ages of silicic tephras containing minerals that crystallized over protracted intervals or that are plagued by incorporation of xenocrysts and/or antecrysts. References: Lajoie, K., 1968, PhD Dissertation, UC Berkeley; Zimmerman et al., 2006, EPSL 252: 94-106.

Real-time supervisor system based on trinary logic to control experiments with behaving animals and humans.

PubMed

Kutz, D F; Marzocchi, N; Fattori, P; Cavalcanti, S; Galletti, C

2005-06-01

A new method is presented based on trinary logic able to check the state of different control variables and synchronously record the physiological and behavioral data of behaving animals and humans. The basic information structure of the method is a time interval of defined maximum duration, called time slice, during which the supervisor system periodically checks the status of a specific subset of input channels. An experimental condition is a sequence of time slices subsequently executed according to the final status of the previous time slice. The proposed method implements in its data structure the possibility to branch like an if-else cascade and the possibility to repeat parts of it recursively like the while-loop. Therefore its data structure contains the most basic control structures of programming languages. The method was implemented using a real-time version of LabVIEW programming environment to program and control our experimental setup. Using this supervision system, we synchronously record four analog data channels at 500 Hz (including eye movements) and the time stamps of up to six neurons at 100 kHz. The system reacts with a resolution within 1 ms to changes of state of digital input channels. The system is set to react to changes in eye position with a resolution within 4 ms. The time slices, experimental conditions, and data are handled by relational databases. This facilitates the construction of new experimental conditions and data analysis. The proposed implementation allows continuous recording without an inter-trial gap for data storage or task management. The implementation can be used to drive electrophysiological experiments of behaving animals and psychophysical studies with human subjects.

Platelet-rich plasma for calcific tendinitis of the shoulder: a case report.

PubMed

Seijas, Roberto; Ares, Oscar; Alvarez, Pedro; Cusco, Xavier; Garcia-Balletbo, Montserrat; Cugat, Ramon

2012-04-01

We report a 44-year-old woman with calcific tendinitis of the shoulder treated with platelet-rich plasma injection. Prior to this, she had no improvement of the symptoms after 6 weeks of ultrasound treatment, Codman exercises, and anti-inflammatory treatment. Platelet-rich plasma was injected into the subacromial area 3 times at 2-week intervals. She had progressive improvement of pain after 2 weeks, and was asymptomatic at week 6. The patient then underwent the previous protocol of rehabilitation. At the one-year follow-up, the patient was pain-free and had complete resolution of calcific tendinitis. The patient had regained full range of movement and had resumed all her activities.

Toward an orbital chronology for the early Aptian Oceanic Anoxic Event (OAE1a, ~ 120 Ma)

NASA Astrophysics Data System (ADS)

Li, Yong-Xiang; Bralower, Timothy J.; Montañez, Isabel P.; Osleger, David A.; Arthur, Michael A.; Bice, David M.; Herbert, Timothy D.; Erba, Elisabetta; Premoli Silva, Isabella

2008-07-01

The early Aptian Oceanic Anoxic Event (OAE1a, 120 Ma) represents a geologically brief time interval in the mid-Cretaceous greenhouse world that is characterized by increased organic carbon accumulation in marine sediments, sudden biotic changes, and abrupt carbon-isotope excursions indicative of significant perturbations to global carbon cycling. The brevity of these drastic environmental changes (< 10 6 year) and the typically 10 6 year temporal resolution of the available chronologies, however, represent a critical gap in our knowledge of OAE1a. We have conducted a high-resolution investigation of three widely distributed sections, including the Cismon APTICORE in Italy, Santa Rosa Canyon in northeastern Mexico, and Deep Sea Drilling Project (DSDP) Site 398 off the Iberian margin in the North Atlantic Ocean, which represent a range of depositional environments where condensed and moderately expanded OAE1a intervals are recorded. The objectives of this study are to establish orbital chronologies for these sections and to construct a common, high-resolution timescale for OAE1a. Spectral analyses of the closely-spaced (corresponding to ~ 5 to 10 kyr) measurements of calcium carbonate content of the APTICORE, magnetic susceptibility (MS) and anhysteretic remanent magnetization (ARM) of the Santa Rosa samples, and MS, ARM and ARM/IRM, where IRM is isothermal remanent magnetization, of Site 398 samples reveal statistically significant cycles. These cycles exhibit periodicity ratios and modulation patterns similar to those of the mid-Cretaceous orbital cycles, suggesting that orbital variations may have modulated depositional processes. Orbital control allows us to estimate the duration of unique, globally identifiable stages of OAE1a. Although OAE1a had a duration of ~ 1.0 to 1.3 Myr, the initial perturbation represented by the negative carbon-isotope excursion was rapid, lasting for ~ 27-44 kyr. This estimate could serve as a basis for constraining triggering mechanisms for OAE1a.

First LOCSMITH locations of deep moonquakes

NASA Astrophysics Data System (ADS)

Hempel, S.; Knapmeyer, M.; Sens-Schönfelder, C.; Oberst, J.

2008-09-01

Introduction Several thousand seismic events were recorded by the Apollo seismic network from 19691977. Different types of events can be distinguished: meteoroid impacts, thermal quakes and internally caused moonquakes. The latter subdivide into shallow (100 to 300km) and deep moonquakes (700 to 1100km), which are by far the most common events. The deep quakes would be no immediate danger to inhabitated stations on the Earth's Moon because of their relatively low magnitude and great depth. However, they bear important information on lunar structure and evolution, and their distribution probably reflects their source mechanism. In this study, we reinvestigate location patterns of deep lunar quakes. LOCSMITH The core of this study is a new location method (LOCSMITH, [1]). This algorithm uses time intervals rather than time instants as input, which contain the dedicated arrival with probability 1. LOCSMITH models and compares theoretical and actual travel times on a global scale and uses an adaptive grid to search source locations compatible with all observations. The output is a set of all possible hypocenters for the considered region of repeating, tidally triggered moonquake activity, called clusters. The shape and size of these sets gives a better estimate of the location uncertainty than the formal standard deviations returned by classical methods. This is used for grading of deep moonquake clusters according to the currently available data quality. Classification of deep moonquakes As first step, we establish a reciprocal dependence of size and shape of LOCSMITH location clouds on number of arrivals. Four different shapes are recognized, listed here in an order corresponding to decreasing spatial resolution: 1. "Balls", which are well defined and relatively small types of sets resembling the commonly assumed error ellipsoid. These are found in the best cases with many observations. Locations in this shape are obtained for clusters 1, 18 or 33, these were already well located by earlier works [2,3]. 2. The next best shape of a location set is the "banana" as found for clusters 5, 39 or 53 [Fig. 1]. In this case, only limited depth resolution is available, and the solution spreads over a large volume. The size of a "banana" could be minimized by either finding a not yet discovered shear wave arrival or estimating a S arrival time interval by considering the coda instead of a clear S arrival. 3. Shape of clouds we call "cones" are formed by clusters for which no compressional wave arrivals, but three S arrivals were picked. Such solutions were found for clusters 35, 201 or 218 [Fig. 2]. A depth limitation is given only by the surface of the Moon's far side. In previous works, locations of these clusters were usually determined with a fixed depth, thus neglecting all depth uncertainty [2]. 4. The fourth and worst class shows a "disc"like shape with no depth resolution and almost no latitude resolution. Clusters of this class, like 4, 23 or 43, were not located so far. From class 1 ("ball") to 4 ("disc") the amount of possible hypocenters increases. So we also found a correlation between size and shape of volumes containing possible hypocenter solutions. Aim We classified all clusters according to the solution set scheme by using arrival times of [2] with an estimated error of ±10s as input for LOCSMITH. We reprocess selected clusters of each class to come up with the special requirements and possibilities of this new location method. As said above, one of the requirements of LOCSMITH is the definition of a time interval instead of a time instant for input, and an interesting option is using an estimated S arrival time interval derived from coda and scattering model, lacking a clear S arrival. We try to find fully automated methods for each processing step, dependent on the quality of data. Methods For despiking we merged methods by [4] and [5] and achieve very good results even for worst case as already presented in [6]. Prior to stacking we developed a complex multiparameter correlation algorithm to calculate the optimum time shift. Results We present relocations of selected deep moonquakes in context of data availability and quality. Previous locations are often contained in our location clouds, but realistic location uncertainties allow large deviations from the best fitting solutions, including locations on the far side of the Moon. Perspective By developing new methods for data processing and using the LOCSMITH locating algorithm we hope to reduce the location uncertainty sufficiently to make sure that all sources are on the near side, or to prove a far side origin of some of them. This would answer questions of hemispheric symmetry of lunar deep seismicity and the Moon's internal structure. References [1] Knapmeyer (2008) accepted to GJI. [2] Nakamura (2005) JGR, 110, E01001. [3] Lognonné (2003) EPSL, 211, 2744. [4] Bulow (2005) JGR, 110, E10003. [5] Sonnemann (2005) EGU05A07960. [6] Hempel, Knapmeyer, Oberst (2008) EGU2008A07989.

Examining Recovery Trajectories Following Sport-related Concussion Using a Multi-Modal Clinical Assessment Approach

PubMed Central

Henry, Luke C.; Elbin, RJ; Collins, Michael W.; Marchetti, Gregory; Kontos, Anthony P.

2016-01-01

Background Previous research estimates that the majority of athletes with sport-related concussion (SRC) will recover between 7–10 days following injury. This short, temporal window of recovery is predominately based on symptom resolution and cognitive improvement, and does not accurately reflect recent advances to the clinical assessment model. Objective To characterize SRC recovery at 1-week post-injury time intervals on symptom, neurocognitive, and vestibular-oculomotor outcomes, and examine gender differences on SRC recovery time. Methods A prospective, repeated measures design was used to examine the temporal resolution of neurocognitive, symptom, and vestibular-oculomotor impairment in 66 subjects (16.5 ± 1.9 years, range 14–23, 64% male) with SRC. Results Recovery time across all outcomes was between 21–28 days post SRC for most athletes. Symptoms demonstrated the greatest improvement in the first 2 weeks, while neurocognitive impairment lingered across various domains up to 28 days post SRC. Vestibular-oculomotor decrements also resolved between one to three weeks post injury. There were no gender differences in neurocognitive recovery. Males were more likely to be asymptomatic by the fourth week and reported less vestibular-oculomotor impairment than females at weeks 1 and 2. Conclusion When utilizing the recommended “comprehensive” approach for concussion assessment, recovery time for SRC is approximately three to four weeks, which is longer than the commonly reported 7–14 days. Sports medicine clinicians should use a variety of complementing assessment tools to capture the heterogeneity of SRC. PMID:26445375

Clinical performance of a free-breathing spatiotemporally accelerated 3-D time-resolved contrast-enhanced pediatric abdominal MR angiography.

PubMed

Zhang, Tao; Yousaf, Ufra; Hsiao, Albert; Cheng, Joseph Y; Alley, Marcus T; Lustig, Michael; Pauly, John M; Vasanawala, Shreyas S

2015-10-01

Pediatric contrast-enhanced MR angiography is often limited by respiration, other patient motion and compromised spatiotemporal resolution. To determine the reliability of a free-breathing spatiotemporally accelerated 3-D time-resolved contrast-enhanced MR angiography method for depicting abdominal arterial anatomy in young children. With IRB approval and informed consent, we retrospectively identified 27 consecutive children (16 males and 11 females; mean age: 3.8 years, range: 14 days to 8.4 years) referred for contrast-enhanced MR angiography at our institution, who had undergone free-breathing spatiotemporally accelerated time-resolved contrast-enhanced MR angiography studies. A radio-frequency-spoiled gradient echo sequence with Cartesian variable density k-space sampling and radial view ordering, intrinsic motion navigation and intermittent fat suppression was developed. Images were reconstructed with soft-gated parallel imaging locally low-rank method to achieve both motion correction and high spatiotemporal resolution. Quality of delineation of 13 abdominal arteries in the reconstructed images was assessed independently by two radiologists on a five-point scale. Ninety-five percent confidence intervals of the proportion of diagnostically adequate cases were calculated. Interobserver agreements were also analyzed. Eleven out of 13 arteries achieved acceptable image quality (mean score range: 3.9-5.0) for both readers. Fair to substantial interobserver agreement was reached on nine arteries. Free-breathing spatiotemporally accelerated 3-D time-resolved contrast-enhanced MR angiography frequently yields diagnostic image quality for most abdominal arteries in young children.

Effects of Head Rotation and Head Tilt on Pharyngeal Pressure Events Using High Resolution Manometry.

PubMed

Kim, Cheol Ki; Ryu, Ju Seok; Song, Sun Hong; Koo, Jung Hoi; Lee, Kyung Duck; Park, Hee Sun; Oh, Yoongul; Min, Kyunghoon

2015-06-01

To observe changes in pharyngeal pressure during the swallowing process according to postures in normal individuals using high-resolution manometry (HRM). Ten healthy volunteers drank 5 mL of water twice while sitting in a neutral posture. Thereafter, they drank the same amount of water twice in the head rotation and head tilting postures. The pressure and time during the deglutition process for each posture were measured with HRM. The data obtained for these two postures were compared with those obtained from the neutral posture. The maximum pressure, area, rise time, and duration in velopharynx (VP) and tongue base (TB) were not affected by changes in posture. In comparison, the maximum pressure and the pre-upper esophageal sphincter (UES) maximum pressure of the lower pharynx in the counter-catheter head rotation posture were lower than those in the neutral posture. The lower pharynx pressure in the catheter head tilting posture was higher than that in the counter-catheter head tilting. The changes in the VP peak and epiglottis, VP and TB peaks, and the VP onset and post-UES time intervals were significant in head tilting and head rotation toward the catheter postures, as compared with neutral posture. The pharyngeal pressure and time parameter analysis using HRM determined the availability of head rotation as a compensatory technique for safe swallowing. Tilting the head smoothes the progress of food by increasing the pressure in the pharynx.

Effects of Head Rotation and Head Tilt on Pharyngeal Pressure Events Using High Resolution Manometry

PubMed Central

Kim, Cheol Ki; Song, Sun Hong; Koo, Jung Hoi; Lee, Kyung Duck; Park, Hee Sun; Oh, Yoongul; Min, Kyunghoon

2015-01-01

Objective To observe changes in pharyngeal pressure during the swallowing process according to postures in normal individuals using high-resolution manometry (HRM). Methods Ten healthy volunteers drank 5 mL of water twice while sitting in a neutral posture. Thereafter, they drank the same amount of water twice in the head rotation and head tilting postures. The pressure and time during the deglutition process for each posture were measured with HRM. The data obtained for these two postures were compared with those obtained from the neutral posture. Results The maximum pressure, area, rise time, and duration in velopharynx (VP) and tongue base (TB) were not affected by changes in posture. In comparison, the maximum pressure and the pre-upper esophageal sphincter (UES) maximum pressure of the lower pharynx in the counter-catheter head rotation posture were lower than those in the neutral posture. The lower pharynx pressure in the catheter head tilting posture was higher than that in the counter-catheter head tilting. The changes in the VP peak and epiglottis, VP and TB peaks, and the VP onset and post-UES time intervals were significant in head tilting and head rotation toward the catheter postures, as compared with neutral posture. Conclusion The pharyngeal pressure and time parameter analysis using HRM determined the availability of head rotation as a compensatory technique for safe swallowing. Tilting the head smoothes the progress of food by increasing the pressure in the pharynx. PMID:26161349

Examining Recovery Trajectories After Sport-Related Concussion With a Multimodal Clinical Assessment Approach.

PubMed

Henry, Luke C; Elbin, R J; Collins, Michael W; Marchetti, Gregory; Kontos, Anthony P

2016-02-01

Previous research estimates that the majority of athletes with sport-related concussion (SRC) will recover between 7 and 10 days after injury. This short temporal window of recovery is based predominately on symptom resolution and cognitive improvement and does not accurately reflect recent advances in the clinical assessment model. To characterize SRC recovery at 1-week postinjury time intervals on symptom, neurocognitive, and vestibular-oculomotor outcomes and to examine sex differences in SRC recovery time. A prospective, repeated-measures design was used to examine the temporal resolution of neurocognitive, symptom, and vestibular-oculomotor impairment in 66 subjects (age, 16.5 ± 1.9 years; range, 14-23 years; 64% male) with SRC. Recovery time across all outcomes was between 21 and 28 days after SRC for most athletes. Symptoms demonstrated the greatest improvement in the first 2 weeks, although neurocognitive impairment lingered across various domains up to 28 days after SRC. Vestibular-oculomotor decrements also resolved between 1 and 3 weeks after injury. There were no sex differences in neurocognitive recovery. Male subjects were more likely to be asymptomatic by the fourth week and reported less vestibular-oculomotor impairment than female subjects at weeks 1 and 2. When the recommended "comprehensive" approach is used for concussion assessment, recovery time for SRC is approximately 3 to 4 weeks, which is longer than the commonly reported 7 to 14 days. Sports medicine clinicians should use a variety of complementing assessment tools to capture the heterogeneity of SRC.

Abrupt Changes at the Permian/Triassic Boundary: Tempo of Events from High-Resolution Cyclostratigraphy

NASA Technical Reports Server (NTRS)

Rampino, M. R.; Prokoph, A.; Adler, A. C.

2000-01-01

The Permian/Triassic (P/Tr) boundary (251.4 +/- 3 Myr) is marked by the most severe mass extinction in the geologic record. Recently, precise absolute dating has bracketed the marine extinctions and associated carbon-isotope anomaly within less than 1 Myr. We improve this resolution through high-resolution stratigraphy across the P/Tr boundary in the 331-m Gartnerkofel-1 core and nearby Reppwand outcrop section (Carnic Alps, Austria) utilizing FFT and wavelet timeseries analyses of cyclic components in down-hole core logs of density and natural gamma-ray intensity, and carbon-isotopic ratios of bulk samples. The wavelet analysis indicates continuity of deposition across the P/Tr boundary interval, and the timeseries analyses show evidence for persistent cycles in the ratio of approximately 40: 10: 4.7: 2.3 meters, correlated with Milankovitch-band orbital cycles of approximately 412: 100: 40: 20 kyr (eccentricity 1 and 2, obliquity, and precession), and giving a consistent average sedimentation rate of approximately 10 cm/1,000 yr. Milankovitch periods in delta C-13 and density in these shallow-water carbonates were most likely the result of climatically induced oscillations of sea level and climate, coupled with changes in ocean circulation and productivity, that affected sedimentation. Fluctuations in gamma radiation reflect varying input of clay minerals and the presence of shaly interbeds. Throughout the P/Tr boundary interval in the core, the 100,000-year eccentricity cycle seems to be dominant. Weaker obliquity and precession cycles are in line with the location of the Austrian section in the latest Permian, close to the Equator in the western bight of the Tethys, where obliquity and precessional effects on seasonal contrast might be subdued. Using the improved resolution provided by cycle analysis in the GK-1 core, we find that the dramatic change in the faunal record that marks the P/Tr boundary takes place over less than 6m, or less than 60,000 years. In the nearby Reppwand outcrop section, the same faunal changes occurs over only 0.8 m or about 8,000 years, close to the limit of time-resolution induced by bioturbation and reworking in these sediments. The sharp negative global carbon-isotope shift took place within less than or equal to 40,000 yr, and the isotope excursions persisted for approximately 480,000 yr into the Early Triassic. The results indicate that the severe marine faunal event that marks the P/Tr boundary was very sudden, perhaps less than the resolution window in the GK-1 core, and suggest a catastrophic cause. The wavelet-analysis approach to high-resolution cyclostratigraphy can be applied to other P/Tr boundary sections, and when combined with precise absolute dating and magnetostratigraphic methods promises a significant increase in resolution in determining the correlation and tempo of the end-Permian extinctions and related events worldwide.

A new modem for microwave time synchronisation via geosynchronous telecommunication satellites

NASA Astrophysics Data System (ADS)

Dienert, Michael

1992-06-01

A study illustrating the two way time transfer technique and describing the use of this technique with the MITREX (Microwave Time and Range Experiment) SATRE (Satellite Time and Range Experiment) modems is presented. The two way time transfer technique via geosynchronous telecom satellites is one of the most accurate methods for synchronization and comparison of remote clocks. Most of the unknown propagation delays can be eliminated by the two way principle. The use of a coherent spread spectrum technique with a truncated pseudonoise code offers a resolution better than 30 ps of the measured time interval. The receiver is built around a Delay Locked Loop (DLL), which correlates the received signal with the known PN sequence to derive the control signal of the loop. In the locked state both PN sequences are synchronous and tracking errors of less than 30 ps are possible. Results showing the accuracy of the modem depending on signal to noise ratio and variation of total input power levels are presented and show that the expected improvement of the jitter of the internal delay by an increase of the chip rate is possible.

Splitting attention reduces temporal resolution from 7 Hz for tracking one object to <3 Hz when tracking three.

PubMed

Holcombe, Alex O; Chen, Wei-Ying

2013-01-09

Overall performance when tracking moving targets is known to be poorer for larger numbers of targets, but the specific effect on tracking's temporal resolution has never been investigated. We document a broad range of display parameters for which visual tracking is limited by temporal frequency (the interval between when a target is at each location and a distracter moves in and replaces it) rather than by object speed. We tested tracking of one, two, and three moving targets while the eyes remained fixed. Variation of the number of distracters and their speed revealed both speed limits and temporal frequency limits on tracking. The temporal frequency limit fell from 7 Hz with one target to 4 Hz with two targets and 2.6 Hz with three targets. The large size of this performance decrease implies that in the two-target condition participants would have done better by tracking only one of the two targets and ignoring the other. These effects are predicted by serial models involving a single tracking focus that must switch among the targets, sampling the position of only one target at a time. If parallel processing theories are to explain why dividing the tracking resource reduces temporal resolution so markedly, supplemental assumptions will be required.

Timescale- and Sensory Modality-Dependency of the Central Tendency of Time Perception.

PubMed

Murai, Yuki; Yotsumoto, Yuko

2016-01-01

When individuals are asked to reproduce intervals of stimuli that are intermixedly presented at various times, longer intervals are often underestimated and shorter intervals overestimated. This phenomenon may be attributed to the central tendency of time perception, and suggests that our brain optimally encodes a stimulus interval based on current stimulus input and prior knowledge of the distribution of stimulus intervals. Two distinct systems are thought to be recruited in the perception of sub- and supra-second intervals. Sub-second timing is subject to local sensory processing, whereas supra-second timing depends on more centralized mechanisms. To clarify the factors that influence time perception, the present study investigated how both sensory modality and timescale affect the central tendency. In Experiment 1, participants were asked to reproduce sub- or supra-second intervals, defined by visual or auditory stimuli. In the sub-second range, the magnitude of the central tendency was significantly larger for visual intervals compared to auditory intervals, while visual and auditory intervals exhibited a correlated and comparable central tendency in the supra-second range. In Experiment 2, the ability to discriminate sub-second intervals in the reproduction task was controlled across modalities by using an interval discrimination task. Even when the ability to discriminate intervals was controlled, visual intervals exhibited a larger central tendency than auditory intervals in the sub-second range. In addition, the magnitude of the central tendency for visual and auditory sub-second intervals was significantly correlated. These results suggest that a common modality-independent mechanism is responsible for the supra-second central tendency, and that both the modality-dependent and modality-independent components of the timing system contribute to the central tendency in the sub-second range.

Analyses of school commuting data for exposure modeling purposes.

PubMed

Xue, Jianping; McCurdy, Thomas; Burke, Janet; Bhaduri, Budhendra; Liu, Cheng; Nutaro, James; Patterson, Lauren

2010-01-01

Human exposure models often make the simplifying assumption that school children attend school in the same census tract where they live. This paper analyzes that assumption and provides information on the temporal and spatial distributions associated with school commuting. The data were obtained using Oak Ridge National Laboratory's LandScan USA population distribution model applied to Philadelphia, PA. It is a high-resolution model used to allocate individual school-aged children to both a home and school location, and to devise a minimum-time home-to-school commuting path (called a trace) between the two locations. LandScan relies heavily on Geographic Information System (GIS) data. With respect to school children attending school in their home census tract, the vast majority does not in Philadelphia. Our analyses found that: (1) about 32% of the students walk across two or more census tracts going to school and 40% of them walk across four or more census blocks; and (2) 60% drive across four or more census tracts going to school and 50% drive across 10 or more census blocks. We also find that: (3) using a 5-min commuting time interval - as opposed to the modeled "trace" - results in misclassifying the "actual" path taken in 90% of the census blocks, 70% of the block groups, and 50% of the tracts; (4) a 1-min time interval is needed to reasonably resolve time spent in the various census unit designations; and (5) approximately 50% of both the homes and schools of Philadelphia school children are located within 160 m of highly traveled roads, and 64% of the schools are located within 200 m. These findings are very important when modeling school children's exposures, especially, when ascertaining the impacts of near-roadway concentrations on their total daily body burden. As many school children also travel along these streets and roadways to get to school, a majority of children in Philadelphia are in mobile source-dominated locations most of the day. We hypothesize that exposures of school children in Philadelphia to benzene and particulate matter will be much higher than if home and school locations and commuting paths at a 1-min time resolution are not explicitly modeled in an exposure assessment. Undertaking such an assessment will be the topic of a future paper.

The potential of urban rainfall monitoring with crowdsourced automatic weather stations in Amsterdam

NASA Astrophysics Data System (ADS)

de Vos, Lotte; Leijnse, Hidde; Overeem, Aart; Uijlenhoet, Remko

2017-02-01

The high density of built-up areas and resulting imperviousness of the land surface makes urban areas vulnerable to extreme rainfall, which can lead to considerable damage. In order to design and manage cities to be able to deal with the growing number of extreme rainfall events, rainfall data are required at higher temporal and spatial resolutions than those needed for rural catchments. However, the density of operational rainfall monitoring networks managed by local or national authorities is typically low in urban areas. A growing number of automatic personal weather stations (PWSs) link rainfall measurements to online platforms. Here, we examine the potential of such crowdsourced datasets for obtaining the desired resolution and quality of rainfall measurements for the capital of the Netherlands. Data from 63 stations in Amsterdam (˜ 575 km2) that measure rainfall over at least 4 months in a 17-month period are evaluated. In addition, a detailed assessment is made of three Netatmo stations, the largest contributor to this dataset, in an experimental setup. The sensor performance in the experimental setup and the density of the PWS network are promising. However, features in the online platforms, like rounding and thresholds, cause changes from the original time series, resulting in considerable errors in the datasets obtained. These errors are especially large during low-intensity rainfall, although they can be reduced by accumulating rainfall over longer intervals. Accumulation improves the correlation coefficient with gauge-adjusted radar data from 0.48 at 5 min intervals to 0.60 at hourly intervals. Spatial rainfall correlation functions derived from PWS data show much more small-scale variability than those based on gauge-adjusted radar data and those found in similar research using dedicated rain gauge networks. This can largely be attributed to the noise in the PWS data resulting from both the measurement setup and the processes occurring in the data transfer to the online PWS platform. A double mass comparison with gauge-adjusted radar data shows that the median of the stations resembles the rainfall reference better than the real-time (unadjusted) radar product. Averaging nearby raw PWS measurements further improves the match with gauge-adjusted radar data in that area. These results confirm that the growing number of internet-connected PWSs could successfully be used for urban rainfall monitoring.

Urban rainfall monitoring with crowdsourced automatic weather stations in Amsterdam

NASA Astrophysics Data System (ADS)

de Vos, Lotte; Leijnse, Hidde; Overeem, Aart; Uijlenhoet, Remko

2017-04-01

The high density of built-up areas and resulting imperviousness of the land surface makes urban areas vulnerable to extreme rainfall, which can lead to considerable damage. In order to design and manage cities to be able to deal with the growing number of extreme rainfall events, rainfall data is required at higher temporal and spatial resolutions than those needed for rural catchments. However, the density of operational rainfall monitoring networks managed by local or national authorities is typically low in urban areas. A growing number of automatic personal weather stations (PWSs) link rainfall measurements to online platforms. Here, we examine the potential of such crowdsourced datasets for obtaining the desired resolution and quality of rainfall measurements for the capital of the Netherlands. Data from 63 stations in Amsterdam (˜575 km2}) that measure rainfall over at least 4 months in a 17-month period are evaluated. In addition, a detailed assessment is made of three Netatmo stations, the largest contributor to this dataset, in an experimental set-up. The sensor performance in the experimental set-up and the density of the PWS-network are promising. However, features in the online platforms, like rounding and thresholds, cause changes from the original time series, resulting in considerable errors in the datasets obtained. These errors are especially large during low intensity rainfall, although they can be reduced by accumulating rainfall over longer intervals. Accumulation improves the correlation coefficient with gauge-adjusted radar data from 0.48 at 5 min intervals to 0.60 at hourly intervals. Spatial rainfall correlation functions derived from PWS data show much more small-scale variability than those based on gauge-adjusted radar data and those found in similar research using dedicated rain gauge networks. This can largely be attributed to the noise in the PWS data resulting from both the measurement setup and the processes occurring in the data transfer to the online PWS-platform. A double mass comparison with gauge-adjusted radar data shows that the median of the stations resembles the rainfall reference better than the real-time (unadjusted) radar product. Averaging nearby raw PWS measurements further improves the match with gauge-adjusted radar data in that area. These results confirm that the growing number of internet-connected PWSs could successfully be used for urban rainfall monitoring.

Three-dimensional localization of abnormal EEG activity in migraine: a low resolution electromagnetic tomography (LORETA) study of migraine patients in the pain-free interval.

PubMed

Clemens, Béla; Bánk, József; Piros, Pálma; Bessenyei, Mónika; Veto, Sára; Tóth, Márton; Kondákor, István

2008-09-01

Investigating the brain of migraine patients in the pain-free interval may shed light on the basic cerebral abnormality of migraine, in other words, the liability of the brain to generate migraine attacks from time to time. Twenty unmedicated "migraine without aura" patients and a matched group of healthy controls were investigated in this explorative study. 19-channel EEG was recorded against the linked ears reference and was on-line digitized. 60 x 2-s epochs of eyes-closed, waking-relaxed activity were subjected to spectral analysis and a source localization method, low resolution electromagnetic tomography (LORETA). Absolute power was computed for 19 electrodes and four frequency bands (delta: 1.5-3.5 Hz, theta: 4.0-7.5 Hz, alpha: 8.0-12.5 Hz, beta: 13.0-25.0 Hz). LORETA "activity" (=current source density, ampers/meters squared) was computed for 2394 voxels and the above specified frequency bands. Group comparison was carried out for the specified quantitative EEG variables. Activity in the two groups was compared on a voxel-by-voxel basis for each frequency band. Statistically significant (uncorrected P < 0.01) group differences were projected to cortical anatomy. Spectral findings: there was a tendency for more alpha power in the migraine that in the control group in all but two (F4, C3) derivations. However, statistically significant (P < 0.01, Bonferroni-corrected) spectral difference was only found in the right occipital region. The main LORETA-finding was that voxels with P < 0.01 differences were crowded in anatomically contiguous cortical areas. Increased alpha activity was found in a cortical area including part of the precuneus, and the posterior part of the middle temporal gyrus in the right hemisphere. Decreased alpha activity was found bilaterally in medial parts of the frontal cortex including the anterior cingulate and the superior and medial frontal gyri. Neither spectral analysis, nor LORETA revealed statistically significant differences in the delta, theta, and beta bands. LORETA revealed the anatomical distribution of the cortical sources (generators) of the EEG abnormalities in migraine. The findings characterize the state of the cerebral cortex in the pain-free interval and might be suitable for planning forthcoming investigations.

Analysis of dynamics of vulcanian activity of Ubinas volcano, using multicomponent seismic antennas

NASA Astrophysics Data System (ADS)

Inza, L. A.; Métaxian, J. P.; Mars, J. I.; Bean, C. J.; O'Brien, G. S.; Macedo, O.; Zandomeneghi, D.

2014-01-01

A series of 16 vulcanian explosions occurred at Ubinas volcano between May 24 and June 14, 2009. The intervals between explosions were from 2.1 h to more than 6 days (mean interval, 33 h). Considering only the first nine explosions, the average time interval was 7.8 h. Most of the explosions occurred after a short time interval (< 8 h) and had low energy, which suggests that the refilling time was not sufficient for large accumulation of gas. A tremor episode followed 75% of the explosions, which coincided with pulses of ash emission. The durations of the tremors following the explosions were longer for the two highest energy explosions. To better understand the physical processes associated with these eruptive events, we localized the sources of explosions using two seismic antennas that were composed of three-component 10 and 12 sensors. We used the high-resolution MUSIC-3C algorithm to estimate the slowness vector for the first waves that composed the explosion signals recorded by the two antennas assuming propagation in a homogeneous medium. The initial part of the explosions was dominated by two frequencies, at 1.1 Hz and 1.5 Hz, for which we identified two separated sources located at 4810 m and 3890 m +/- 390 altitude, respectively. The position of these two sources was the same for the full 16 explosions. This implies the reproduction of similar mechanisms in the conduit. Based on the eruptive mechanisms proposed for other volcanoes of the same type, we interpret the position of these two sources as the limits of the conduit portion that was involved in the fragmentation process. Seismic data and ground deformation recorded simultaneously less than 2 km from the crater showed a decompression movement 2 s prior to each explosion. This movement can be interpreted as gas leakage at the level of the cap before its destruction. The pressure drop generated in the conduit could be the cause of the fragmentation process that propagated deeper. Based on these observations, we interpret the position of the highest source as the part of the conduit under the cap, and the deeper source as the limit of the fragmentation zone.

A study of the Herald-Phillipstown fault in the Wabash Valley using drillhole and 3-D seismic reflection data

NASA Astrophysics Data System (ADS)

Kroenke, Samantha E.

In June 2009, a 2.2 square mile 3-D high resolution seismic reflection survey was shot in southeastern Illinois in the Phillipstown Consolidated oilfield. A well was drilled in the 3-D survey area to tie the seismic to the geological data with a synthetic seismogram from the sonic log. The objectives of the 3-D seismic survey were three-fold: (1) To image and interpret faulting of the Herald-Phillipstown Fault using drillhole-based geological and seismic cross-sections and structural contour maps created from the drillhole data and seismic reflection data, (2) To test the effectiveness of imaging the faults by selected seismic attributes, and (3) To compare spectral decomposition amplitude maps with an isochron map and an isopach map of a selected geologic interval (VTG interval). Drillhole and seismic reflection data show that various formation offsets increase near the main Herald-Phillipstown fault, and that the fault and its large offset subsidiary faults penetrate the Precambrian crystalline basement. A broad, northeast-trending 10,000 feet wide graben is consistently observed in the drillhole data. Both shallow and deep formations in the geological cross-sections reveal small horst and graben features within the broad graben created possibly in response to fault reactivations. The HPF faults have been interpreted as originally Precambrian age high-angle, normal faults reactivated with various amounts and types of offset. Evidence for strike-slip movement is also clear on several faults. Changes in the seismic attribute values in the selected interval and along various time slices throughout the whole dataset correlate with the Herald-Phillipstown faults. Overall, seismic attributes could provide a means of mapping large offset faults in areas with limited or absent drillhole data. Results of the spectral decomposition suggest that if the interval velocity is known for a particular formation or interval, high-resolution 3-D seismic reflection surveys could utilize these amplitudes as an alternative seismic interpretation method for estimating formation thicknesses. A VTG isopach map was compared with an isochron map and a spectral decomposition amplitude map. The results reveal that the isochron map strongly correlates with the isopach map as well as the spectral decomposition map. It was also found that thicker areas in the isopach correlated with higher amplitude values in the spectral decomposition amplitude map. Offsets along the faults appear sharper in these amplitudes and isochron maps than in the isopach map, possibly as a result of increased spatial sampling.

Ultrafast Synthetic Transmit Aperture Imaging Using Hadamard-Encoded Virtual Sources With Overlapping Sub-Apertures.

PubMed

Ping Gong; Pengfei Song; Shigao Chen

2017-06-01

The development of ultrafast ultrasound imaging offers great opportunities to improve imaging technologies, such as shear wave elastography and ultrafast Doppler imaging. In ultrafast imaging, there are tradeoffs among image signal-to-noise ratio (SNR), resolution, and post-compounded frame rate. Various approaches have been proposed to solve this tradeoff, such as multiplane wave imaging or the attempts of implementing synthetic transmit aperture imaging. In this paper, we propose an ultrafast synthetic transmit aperture (USTA) imaging technique using Hadamard-encoded virtual sources with overlapping sub-apertures to enhance both image SNR and resolution without sacrificing frame rate. This method includes three steps: 1) create virtual sources using sub-apertures; 2) encode virtual sources using Hadamard matrix; and 3) add short time intervals (a few microseconds) between transmissions of different virtual sources to allow overlapping sub-apertures. The USTA was tested experimentally with a point target, a B-mode phantom, and in vivo human kidney micro-vessel imaging. Compared with standard coherent diverging wave compounding with the same frame rate, improvements on image SNR, lateral resolution (+33%, with B-mode phantom imaging), and contrast ratio (+3.8 dB, with in vivo human kidney micro-vessel imaging) have been achieved. The f-number of virtual sources, the number of virtual sources used, and the number of elements used in each sub-aperture can be flexibly adjusted to enhance resolution and SNR. This allows very flexible optimization of USTA for different applications.

Measuring the EMS patient access time interval and the impact of responding to high-rise buildings.

PubMed

Morrison, Laurie J; Angelini, Mark P; Vermeulen, Marian J; Schwartz, Brian

2005-01-01

To measure the patient access time interval and characterize its contribution to the total emergency medical services (EMS) response time interval; to compare the patient access time intervals for patients located three or more floors above ground with those less than three floors above or below ground, and specifically in the apartment subgroup; and to identify barriers that significantly impede EMS access to patients in high-rise apartments. An observational study of all patients treated by an emergency medical technician paramedics (EMT-P) crew was conducted using a trained independent observer to collect time intervals and identify potential barriers to access. Of 118 observed calls, 25 (21%) originated from patients three or more floors above ground. The overall median and 90th percentile (95% confidence interval) patient access time intervals were 1.61 (1.27, 1.91) and 3.47 (3.08, 4.05) minutes, respectively. The median interval was 2.73 (2.22, 3.03) minutes among calls from patients located three or more stories above ground compared with 1.25 (1.07, 1.55) minutes among those at lower levels. The patient access time interval represented 23.5% of the total EMS response time interval among calls originating less than three floors above or below ground and 32.2% of those located three or more stories above ground. The most frequently encountered barriers to access included security code entry requirements, lack of directional signs, and inability to fit the stretcher into the elevator. The patient access time interval is significantly long and represents a substantial component of the total EMS response time interval, especially among ambulance calls originating three or more floors above ground. A number of barriers appear to contribute to delayed paramedic access.

Modulation of human time processing by subthalamic deep brain stimulation.

PubMed

Wojtecki, Lars; Elben, Saskia; Timmermann, Lars; Reck, Christiane; Maarouf, Mohammad; Jörgens, Silke; Ploner, Markus; Südmeyer, Martin; Groiss, Stefan Jun; Sturm, Volker; Niedeggen, Michael; Schnitzler, Alfons

2011-01-01

Timing in the range of seconds referred to as interval timing is crucial for cognitive operations and conscious time processing. According to recent models of interval timing basal ganglia (BG) oscillatory loops are involved in time interval recognition. Parkinsońs disease (PD) is a typical disease of the basal ganglia that shows distortions in interval timing. Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is a powerful treatment of PD which modulates motor and cognitive functions depending on stimulation frequency by affecting subcortical-cortical oscillatory loops. Thus, for the understanding of BG-involvement in interval timing it is of interest whether STN-DBS can modulate timing in a frequency dependent manner by interference with oscillatory time recognition processes. We examined production and reproduction of 5 and 15 second intervals and millisecond timing in a double blind, randomised, within-subject repeated-measures design of 12 PD-patients applying no, 10-Hz- and ≥ 130-Hz-STN-DBS compared to healthy controls. We found under(re-)production of the 15-second interval and a significant enhancement of this under(re-)production by 10-Hz-stimulation compared to no stimulation, ≥ 130-Hz-STN-DBS and controls. Milliseconds timing was not affected. We provide first evidence for a frequency-specific modulatory effect of STN-DBS on interval timing. Our results corroborate the involvement of BG in general and of the STN in particular in the cognitive representation of time intervals in the range of multiple seconds.

Modulation of Human Time Processing by Subthalamic Deep Brain Stimulation

PubMed Central

Timmermann, Lars; Reck, Christiane; Maarouf, Mohammad; Jörgens, Silke; Ploner, Markus; Südmeyer, Martin; Groiss, Stefan Jun; Sturm, Volker; Niedeggen, Michael; Schnitzler, Alfons

2011-01-01

Timing in the range of seconds referred to as interval timing is crucial for cognitive operations and conscious time processing. According to recent models of interval timing basal ganglia (BG) oscillatory loops are involved in time interval recognition. Parkinsońs disease (PD) is a typical disease of the basal ganglia that shows distortions in interval timing. Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is a powerful treatment of PD which modulates motor and cognitive functions depending on stimulation frequency by affecting subcortical-cortical oscillatory loops. Thus, for the understanding of BG-involvement in interval timing it is of interest whether STN-DBS can modulate timing in a frequency dependent manner by interference with oscillatory time recognition processes. We examined production and reproduction of 5 and 15 second intervals and millisecond timing in a double blind, randomised, within-subject repeated-measures design of 12 PD-patients applying no, 10-Hz- and ≥130-Hz-STN-DBS compared to healthy controls. We found under(re-)production of the 15-second interval and a significant enhancement of this under(re-)production by 10-Hz-stimulation compared to no stimulation, ≥130-Hz-STN-DBS and controls. Milliseconds timing was not affected. We provide first evidence for a frequency-specific modulatory effect of STN-DBS on interval timing. Our results corroborate the involvement of BG in general and of the STN in particular in the cognitive representation of time intervals in the range of multiple seconds. PMID:21931767

Patient navigation significantly reduces delays in breast cancer diagnosis in the District of Columbia.

PubMed

Hoffman, Heather J; LaVerda, Nancy L; Young, Heather A; Levine, Paul H; Alexander, Lisa M; Brem, Rachel; Caicedo, Larisa; Eng-Wong, Jennifer; Frederick, Wayne; Funderburk, William; Huerta, Elmer; Swain, Sandra; Patierno, Steven R

2012-10-01

Patient Navigation (PN) originated in Harlem as an intervention to help poor women overcome access barriers to timely breast cancer treatment. Despite rapid, nationally widespread adoption of PN, empirical evidence on its effectiveness is lacking. In 2005, National Cancer Institute initiated a multicenter PN Research Program (PNRP) to measure PN effectiveness for several cancers. The George Washington Cancer Institute, a project participant, established District of Columbia (DC)-PNRP to determine PN's ability to reduce breast cancer diagnostic time (number of days from abnormal screening to definitive diagnosis). A total of 2,601 women (1,047 navigated; 1,554 concurrent records-based nonnavigated) were examined for breast cancer from 2006 to 2010 at 9 hospitals/clinics in DC. Analyses included only women who reached complete diagnostic resolution. Differences in diagnostic time between navigation groups were tested with ANOVA models including categorical demographic and treatment variables. Log transformations normalized diagnostic time. Geometric means were estimated and compared using Tukey-Kramer P value adjustments. Average-geometric mean [95% confidence interval (CI)]-diagnostic time (days) was significantly shorter for navigated, 25.1 (21.7, 29.0), than nonnavigated women, 42.1 (35.8, 49.6). Subanalyses revealed significantly shorter average diagnostic time for biopsied navigated women, 26.6 (21.8, 32.5) than biopsied nonnavigated women, 57.5 (46.3, 71.5). Among nonbiopsied women, diagnostic time was shorter for navigated, 27.2 (22.8, 32.4), than nonnavigated women, 34.9 (29.2, 41.7), but not statistically significant. Navigated women, especially those requiring biopsy, reached their diagnostic resolution significantly faster than nonnavigated women. Results support previous findings of PN's positive influence on health care. PN should be a reimbursable expense to assure continuation of PN programs. 2012 AACR

Estimation of the stand ages of tropical secondary forests after shifting cultivation based on the combination of WorldView-2 and time-series Landsat images

NASA Astrophysics Data System (ADS)

Fujiki, Shogoro; Okada, Kei-ichi; Nishio, Shogo; Kitayama, Kanehiro

2016-09-01

We developed a new method to estimate stand ages of secondary vegetation in the Bornean montane zone, where local people conduct traditional shifting cultivation and protected areas are surrounded by patches of recovering secondary vegetation of various ages. Identifying stand ages at the landscape level is critical to improve conservation policies. We combined a high-resolution satellite image (WorldView-2) with time-series Landsat images. We extracted stand ages (the time elapsed since the most recent slash and burn) from a change-detection analysis with Landsat time-series images and superimposed the derived stand ages on the segments classified by object-based image analysis using WorldView-2. We regarded stand ages as a response variable, and object-based metrics as independent variables, to develop regression models that explain stand ages. Subsequently, we classified the vegetation of the target area into six age units and one rubber plantation unit (1-3 yr, 3-5 yr, 5-7 yr, 7-30 yr, 30-50 yr, >50 yr and 'rubber plantation') using regression models and linear discriminant analyses. Validation demonstrated an accuracy of 84.3%. Our approach is particularly effective in classifying highly dynamic pioneer vegetation younger than 7 years into 2-yr intervals, suggesting that rapid changes in vegetation canopies can be detected with high accuracy. The combination of a spectral time-series analysis and object-based metrics based on high-resolution imagery enabled the classification of dynamic vegetation under intensive shifting cultivation and yielded an informative land cover map based on stand ages.

Creating high-resolution time series land-cover classifications in rapidly changing forested areas with BULC-U in Google Earth Engine

NASA Astrophysics Data System (ADS)

Cardille, J. A.; Lee, J.

2017-12-01

With the opening of the Landsat archive, there is a dramatically increased potential for creating high-quality time series of land use/land-cover (LULC) classifications derived from remote sensing. Although LULC time series are appealing, their creation is typically challenging in two fundamental ways. First, there is a need to create maximally correct LULC maps for consideration at each time step; and second, there is a need to have the elements of the time series be consistent with each other, without pixels that flip improbably between covers due only to unavoidable, stray classification errors. We have developed the Bayesian Updating of Land Cover - Unsupervised (BULC-U) algorithm to address these challenges simultaneously, and introduce and apply it here for two related but distinct purposes. First, with minimal human intervention, we produced an internally consistent, high-accuracy LULC time series in rapidly changing Mato Grosso, Brazil for a time interval (1986-2000) in which cropland area more than doubled. The spatial and temporal resolution of the 59 LULC snapshots allows users to witness the establishment of towns and farms at the expense of forest. The new time series could be used by policy-makers and analysts to unravel important considerations for conservation and management, including the timing and location of past development, the rate and nature of changes in forest connectivity, the connection with road infrastructure, and more. The second application of BULC-U is to sharpen the well-known GlobCover 2009 classification from 300m to 30m, while improving accuracy measures for every class. The greatly improved resolution and accuracy permits a better representation of the true LULC proportions, the use of this map in models, and quantification of the potential impacts of changes. Given that there may easily be thousands and potentially millions of images available to harvest for an LULC time series, it is imperative to build useful algorithms requiring minimal human intervention. Through image segmentation and classification, BULC-U allows us to use both the spectral and spatial characteristics of imagery to sharpen classifications and create time series. It is hoped that this study may allow us and other users of this new method to consider time series across ever larger areas.

Contour maps of lunar remanent magnetic fields

NASA Technical Reports Server (NTRS)

Hood, L. L.; Russell, C. T.; Coleman, P. J., Jr.

1981-01-01

The 2605 usable orbits of Apollo 15 and 16 subsatellite magnetometer data have been reexamined for intervals suitable for analysis of crustal magnetic anomalies. To minimize plasma-related disturbances, segments from 274 of these orbits were selected from times when the moon was either in a lobe of the geomagnetic tail or in the solar wind with the subsatellites in the lunar wake. External field contributions which remained in the selected intervals were minimized by (1) quadratic detrending of individual orbit segments with lengths much greater than anomaly wavelengths and (2) two-dimensional filtering with minimum passed wavelengths less than or equal to anomaly wavelengths. Improvements in coverage, accuracy, and resolution of previously published anomaly maps produced from these data are obtained. In addition to improved maps of the Reiner Gamma and Van de Graaff-Aitken anomalies studied previously, a third region of relatively high-amplitude anomalies centered near the crater Gerasimovich on the southeastern far side has been mapped. Both the Van de Graaff-Aitken region and the Gerasimovich region are marked by the general occurrence of extensive groups of Reiner Gamma-type swirls.

Late Pleistocene Magnitude Glacial Incursions of Southern Component Water to the Deep North Atlantic Resolved Using Nd Isotopes during the Intensification of Northern Hemisphere Glaciation (3.3 to 2.4 Ma)

NASA Astrophysics Data System (ADS)

Lang, D.; Bailey, I.; Wilson, P. A.; Foster, G. L.; Gutjahr, M.

2014-12-01

The ocean, through its ability to globally redistribute heat and partition carbon dioxide, is believed to play a key role in driving and amplifying climate change during Quaternary glaciations on orbital to millennial timescales. Relatively little is known, however, about changes in Atlantic Meridional Overturning Circulation (AMOC) associated with the Pliocene intensification of Northern Hemisphere glaciation (iNHG). To help fill this gap in our knowledge we present a new high resolution (~6 ka) record of the Nd isotope composition of the deep North Atlantic between ~3.3 and 2.4 Ma, measured on fish debris at IODP Site U1313 (3426 m, 41°N, 32.5°W). This record represents the first orbital-resolution record of variations in watermass mixing in this region for iNHG independent of changes in the carbon cycle and, in contrast to existing benthic foraminiferal δ13C records for this time interval, our Nd dataset contains evidence for late Pleistocene magnitude incursions of Southern Component Waters to the deep North Atlantic Ocean during key glacial periods through this time. We therefore infer an important role for AMOC variability in amplifying Quaternary glacial-interglacial cycles

Progress in tropical isotope dendroclimatology

NASA Astrophysics Data System (ADS)

Evans, M. N.; Schrag, D. P.; Poussart, P. F.; Anchukaitis, K. J.

2005-12-01

The terrestrial tropics remain an important gap in the growing high resolution proxy network used to characterize the mean state and variability of the hydrological cycle. Here we review early efforts to develop a new class of proxy paleorainfall/humidity indicators using intraseasonal to interannual-resolution stable isotope data from tropical trees. The approach invokes a recently published model of oxygen isotopic composition of alpha-cellulose, rapid methods for cellulose extraction from raw wood, and continuous flow isotope ratio mass spectrometry to develop proxy chronological, rainfall and growth rate estimates from tropical trees, even those lacking annual rings. Isotopically-derived age models may be confirmed for modern intervals using trees of known age, radiocarbon measurements, direct measurements of tree diameter, and time series replication. Studies are now underway at a number of laboratories on samples from Costa Rica, northwestern coastal Peru, Indonesia, Thailand, New Guinea, Paraguay, Brazil, India, and the South American Altiplano. Improved sample extraction chemistry and online pyrolysis techniques should increase sample throughput, precision, and time series replication. Statistical calibration together with simple forward modeling based on the well-observed modern period can provide for objective interpretation of the data. Ultimately, replicated data series with well-defined uncertainties can be entered into multiproxy efforts to define aspects of tropical hydrological variability associated with ENSO, the meridional overturning circulation, and the monsoon systems.

Detection of chlorophyll and leaf area index dynamics from sub-weekly hyperspectral imagery

NASA Astrophysics Data System (ADS)

Houborg, Rasmus; McCabe, Matthew F.; Angel, Yoseline; Middleton, Elizabeth M.

2016-10-01

Temporally rich hyperspectral time-series can provide unique time critical information on within-field variations in vegetation health and distribution needed by farmers to effectively optimize crop production. In this study, a dense timeseries of images were acquired from the Earth Observing-1 (EO-1) Hyperion sensor over an intensive farming area in the center of Saudi Arabia. After correction for atmospheric effects, optimal links between carefully selected explanatory hyperspectral vegetation indices and target vegetation characteristics were established using a machine learning approach. A dataset of in-situ measured leaf chlorophyll (Chll) and leaf area index (LAI), collected during five intensive field campaigns over a variety of crop types, were used to train the rule-based predictive models. The ability of the narrow-band hyperspectral reflectance information to robustly assess and discriminate dynamics in foliar biochemistry and biomass through empirical relationships were investigated. This also involved evaluations of the generalization and reproducibility of the predictions beyond the conditions of the training dataset. The very high temporal resolution of the satellite retrievals constituted a specifically intriguing feature that facilitated detection of total canopy Chl and LAI dynamics down to sub-weekly intervals. The study advocates the benefits associated with the availability of optimum spectral and temporal resolution spaceborne observations for agricultural management purposes.

Time-lapse electrical impedance spectroscopy for monitoring the cell cycle of single immobilized S. pombe cells.

PubMed

Zhu, Zhen; Frey, Olivier; Haandbaek, Niels; Franke, Felix; Rudolf, Fabian; Hierlemann, Andreas

2015-11-26

As a complement and alternative to optical methods, wide-band electrical impedance spectroscopy (EIS) enables multi-parameter, label-free and real-time detection of cellular and subcellular features. We report on a microfluidics-based system designed to reliably capture single rod-shaped Schizosaccharomyces pombe cells by applying suction through orifices in a channel wall. The system enables subsequent culturing of immobilized cells in an upright position, while dynamic changes in cell-cycle state and morphology were continuously monitored through EIS over a broad frequency range. Besides measuring cell growth, clear impedance signals for nuclear division have been obtained. The EIS system has been characterized with respect to sensitivity and detection limits. The spatial resolution in measuring cell length was 0.25 μm, which corresponds to approximately a 5-min interval of cell growth under standard conditions. The comprehensive impedance data sets were also used to determine the occurrence of nuclear division and cytokinesis. The obtained results have been validated through concurrent confocal imaging and plausibilized through comparison with finite-element modeling data. The possibility to monitor cellular and intracellular features of single S. pombe cells during the cell cycle at high spatiotemporal resolution renders the presented microfluidics-based EIS system a suitable tool for dynamic single-cell investigations.

Time-lapse electrical impedance spectroscopy for monitoring the cell cycle of single immobilized S. pombe cells

PubMed Central

Zhu, Zhen; Frey, Olivier; Haandbaek, Niels; Franke, Felix; Rudolf, Fabian; Hierlemann, Andreas

2015-01-01

As a complement and alternative to optical methods, wide-band electrical impedance spectroscopy (EIS) enables multi-parameter, label-free and real-time detection of cellular and subcellular features. We report on a microfluidics-based system designed to reliably capture single rod-shaped Schizosaccharomyces pombe cells by applying suction through orifices in a channel wall. The system enables subsequent culturing of immobilized cells in an upright position, while dynamic changes in cell-cycle state and morphology were continuously monitored through EIS over a broad frequency range. Besides measuring cell growth, clear impedance signals for nuclear division have been obtained. The EIS system has been characterized with respect to sensitivity and detection limits. The spatial resolution in measuring cell length was 0.25 μm, which corresponds to approximately a 5-min interval of cell growth under standard conditions. The comprehensive impedance data sets were also used to determine the occurrence of nuclear division and cytokinesis. The obtained results have been validated through concurrent confocal imaging and plausibilized through comparison with finite-element modeling data. The possibility to monitor cellular and intracellular features of single S. pombe cells during the cell cycle at high spatiotemporal resolution renders the presented microfluidics-based EIS system a suitable tool for dynamic single-cell investigations. PMID:26608589

Velocity and sediment surge: What do we see at times of very shallow water on intertidal mudflats?

NASA Astrophysics Data System (ADS)

Zhang, Qian; Gong, Zheng; Zhang, Changkuan; Townend, Ian; Jin, Chuang; Li, Huan

2016-02-01

A self-designed "bottom boundary layer hydrodynamic and suspended sediment concentration (SSC) measuring system" was built to observe the hydrodynamic and the SSC processes over the intertidal mudflats at the middle part of the Jiangsu coast during August 8-10, 2013. Velocity profiles within 10 cm of the mudflat surface were obtained with a vertical resolution as fine as 1 mm. An ADCP was used to extend the profile over the full water depth with a resolution of 10 cm and the vertical SSC profile was measured at intervals using Optical Backscatter Sensors (OBS). At the same time, water levels and wave conditions were measured with a Tide and Wave Recorder. Measured data suggested that the vertical structure of velocity profiles within 10 cm above the bed maintains a logarithmic distribution during the whole tidal cycle except the slack-water periods. Shallow flows during both the early-flood period and the later-ebb period are characterized by a relatively large vertical velocity gradient and a "surge" feature. We conclude that the very shallow water stages are transient and may not contribute much to the whole water and sediment transport, while they can play a significant role in the formation and evolution of micro-topographies on tidal flats.

Nanosecond Time-Resolved Microscopic Gate-Modulation Imaging of Polycrystalline Organic Thin-Film Transistors

NASA Astrophysics Data System (ADS)

Matsuoka, Satoshi; Tsutsumi, Jun'ya; Matsui, Hiroyuki; Kamata, Toshihide; Hasegawa, Tatsuo

2018-02-01

We develop a time-resolved microscopic gate-modulation (μ GM ) imaging technique to investigate the temporal evolution of the channel current and accumulated charges in polycrystalline pentacene thin-film transistors (TFTs). A time resolution of as high as 50 ns is achieved by using a fast image-intensifier system that could amplify a series of instantaneous optical microscopic images acquired at various time intervals after the stepped gate bias is switched on. The differential images obtained by subtracting the gate-off image allows us to acquire a series of temporal μ GM images that clearly show the gradual propagation of both channel charges and leaked gate fields within the polycrystalline channel layers. The frontal positions for the propagations of both channel charges and leaked gate fields coincide at all the time intervals, demonstrating that the layered gate dielectric capacitors are successively transversely charged up along the direction of current propagation. The initial μ GM images also indicate that the electric field effect is originally concentrated around a limited area with a width of a few micrometers bordering the channel-electrode interface, and that the field intensity reaches a maximum after 200 ns and then decays. The time required for charge propagation over the whole channel region with a length of 100 μ m is estimated at about 900 ns, which is consistent with the measured field-effect mobility and the temporal-response model for organic TFTs. The effect of grain boundaries can be also visualized by comparison of the μ GM images for the transient and the steady states, which confirms that the potential barriers at the grain boundaries cause the transient shift in the accumulated charges or the transient accumulation of additional charges around the grain boundaries.

Very-short range forecasting system for 2018 Pyeonchang Winter Olympic and Paralympic games

NASA Astrophysics Data System (ADS)

Nam, Ji-Eun; Park, Kyungjeen; Kim, Minyou; Kim, Changhwan; Joo, Sangwon

2016-04-01

The 23rd Olympic Winter and the 13th Paralympic Winter Games will be held in Pyeongchang, Republic of Korea respectively from 9 to 25 February 2018 and from 9 to 18 February 2018. The Korea Meteorological Administration (KMA) and the National Institute for Meteorological Science (NIMS) have the responsibility to provide weather information for the management of the Games and the safety of the public. NIMS will carry out a Forecast Demonstration Project (FDP) and a Research and Development Project (RDP) which will be called ICE-POP 2018. These projects will focus on intensive observation campaigns to understand severe winter weathers over the Pyeongchang region, and the research results from the RDP will be used to improve the accuracy of nowcasting and very short-range forecast systems during the Games. To support these projects, NIMS developed Very-short range Data Assimilation and Prediction System (VDAPS), which is run in real time with 1 hour cycling interval and up to 12 hour forecasts. The domain is covering Korean Peninsular and surrounding seas with 1.5km horizontal resolution. AWS, windprofiler, buoy, sonde, aircraft, scatwinds, and radar radial winds are assimilated by 3DVAR on 3km resolution inner domain. The rain rate is converted into latent heat and initialized via nudging. The visibility data are also assimilated with the addition of aerosol control variable. The experiments results show the improvement in rainfall over south sea of Korean peninsula. In order to reduce excessive rainfalls during first 2 hours due to the reduced cycling interval, the data assimilation algorithm is optimized.

VizieR Online Data Catalog: VANDELS High-Redshift Galaxy Evolution (McLure+, 2017)

NASA Astrophysics Data System (ADS)

McLure, R.; Pentericci, L.; Vandels Team

2017-11-01

This is the first data release (DR1) of the VANDELS survey, an ESO public spectroscopy survey targeting the high-redshift Universe. The VANDELS survey uses the VIMOS spectrograph on ESO's VLT to obtain ultra-deep, medium resolution, optical spectra of galaxies within the UKIDSS Ultra Deep Survey (UDS) and Chandra Deep Field South (CDFS) survey fields (0.2 sq. degree total area). Using robust photometric redshift pre-selection, VANDELS is targeting ~2100 galaxies in the redshift interval 1.0=3. In addition, VANDELS is targeting a substantial number of passive galaxies in the redshift interval 1.0

3-D visualisation and interpretation of seismic attributes extracted from large 3-D seismic datasets: Subregional and prospect evaluation, deepwater Nigeria

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

Sola, M.; Haakon Nordby, L.; Dailey, D.V.

High resolution 3-D visualization of horizon interpretation and seismic attributes from large 3-D seismic surveys in deepwater Nigeria has greatly enhanced the exploration team`s ability to quickly recognize prospective segments of subregional and prospect specific scale areas. Integrated workstation generated structure, isopach and extracted horizon consistent, interval and windowed attributes are particularly useful in illustrating the complex structural and stratigraphical prospectivity of deepwater Nigeria. Large 3-D seismic volumes acquired over 750 square kilometers can be manipulated within the visualization system with attribute tracking capability that allows for real time data interrogation and interpretation. As in classical seismic stratigraphic studies, patternmore » recognition is fundamental to effective depositions facies interpretation and reservoir model construction. The 3-D perspective enhances the data interpretation through clear representation of relative scale, spatial distribution and magnitude of attributes. In deepwater Nigeria, many prospective traps rely on an interplay between syndepositional structure and slope turbidite depositional systems. Reservoir systems in many prospects appear to be dominated by unconfined to moderately focused slope feeder channel facies. These units have spatially complex facies architecture with feeder channel axes separated by extensive interchannel areas. Structural culminations generally have a history of initial compressional folding with late in extensional collapse and accommodation faulting. The resulting complex trap configurations often have stacked reservoirs over intervals as thick as 1500 meters. Exploration, appraisal and development scenarios in these settings can be optimized by taking full advantage of integrating high resolution 3-D visualization and seismic workstation interpretation.« less

3-D visualisation and interpretation of seismic attributes extracted from large 3-D seismic datasets: Subregional and prospect evaluation, deepwater Nigeria

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

Sola, M.; Haakon Nordby, L.; Dailey, D.V.

High resolution 3-D visualization of horizon interpretation and seismic attributes from large 3-D seismic surveys in deepwater Nigeria has greatly enhanced the exploration team's ability to quickly recognize prospective segments of subregional and prospect specific scale areas. Integrated workstation generated structure, isopach and extracted horizon consistent, interval and windowed attributes are particularly useful in illustrating the complex structural and stratigraphical prospectivity of deepwater Nigeria. Large 3-D seismic volumes acquired over 750 square kilometers can be manipulated within the visualization system with attribute tracking capability that allows for real time data interrogation and interpretation. As in classical seismic stratigraphic studies, patternmore » recognition is fundamental to effective depositions facies interpretation and reservoir model construction. The 3-D perspective enhances the data interpretation through clear representation of relative scale, spatial distribution and magnitude of attributes. In deepwater Nigeria, many prospective traps rely on an interplay between syndepositional structure and slope turbidite depositional systems. Reservoir systems in many prospects appear to be dominated by unconfined to moderately focused slope feeder channel facies. These units have spatially complex facies architecture with feeder channel axes separated by extensive interchannel areas. Structural culminations generally have a history of initial compressional folding with late in extensional collapse and accommodation faulting. The resulting complex trap configurations often have stacked reservoirs over intervals as thick as 1500 meters. Exploration, appraisal and development scenarios in these settings can be optimized by taking full advantage of integrating high resolution 3-D visualization and seismic workstation interpretation.« less

Multi-core, multi-constraint chronostratigraphic framework over past 50,000 years places high-resolution Gulf of Alaska ocean-ice-sediment history into a global framework

NASA Astrophysics Data System (ADS)

Mix, A. C.; Walczak, M.; Asahi, H.; Belanger, C. L.; Cowan, E. A.; Du, J.; Fallon, S.; Fifield, L. K.; Hobern, T.; Jaeger, J. M.; Jensen, B. J. L.; McKay, J. L.; Padman, J.; Ross, A.; Sharon, S.; Stoner, J. S.; Zellers, S.

2017-12-01

Development of precise chronologies extending older than late glacial time in the subpolar North Pacific has been notoriously difficult due to limited record length in sediment cores, poor carbonate preservation, and (in many cases) relatively low resolution records. This is a key gap in our understanding of Northern Hemisphere and global paleoclimate change, now addressed with results from IODP Expedition 341 in the Gulf of Alaska. Here we utilize marine core and drill sites (U1417, U1418, U1419, U1421 and co-located site-survey cores) some of which provide exceptionally high sustained sedimentation rates (up to 2 cm per year in extended glacial intervals). This facilitates a multifaceted approach to chronology development over the past 50,000 years including radiocarbon, foraminiferal stable isotopes and other geochemical proxies, sediment physical properties, sedimentology, and tephrochronology. Given high sedimentation rates and the superb preservation this provides, we have developed marine time series that rival the resolution of the polar ice core records, which allows us to compare radiocarbon-based chronologies with several strategies involving signal tuning. Such a multifaceted approach mitigates weaknesses in any of the individual methods and allows a rigorous analysis of uncertainties in ages and sediment accumulation rates. The resulting record reveals dynamic changes in the Cordilleran Ice Sheet and North Pacific Ocean and most importantly facilitates placing these records into the context of global climate changes. (We acknowledge the contributions of J. Addison and S. Praetorius, who were not listed as co-authors due to USGS submission rules).

Testing Astronomical and 40Ar/39Ar Timescales for the K/Pg Boundary Interval Using High-Resolution Magnetostratigraphy and U-Pb Geochronology in the Denver Basin of Colorado

NASA Astrophysics Data System (ADS)

Clyde, W.; Bowring, S. A.; Johnson, K. R.; Ramezani, J.; Jones, M. M.

2015-12-01

Accurate and precise calibration of the Geomagnetic Polarity Timescale (GPTS) in absolute time is critical for resolving rates of geological and biological processes which in turn help constrain the underlying causes of those processes. Numerical calibration of the GPTS was traditionally carried out by interpolation between a limited number of 40Ar/39Ar dated volcanic ash deposits from superpositional sequences with well-defined magnetostratigraphies. More recently, the Neogene part of the GPTS has been calibrated using high-resolution astrochronological methods, however the application of these approaches to pre-Neogene parts of the timescale is controversial given the uncertainties in relevant orbital parameters this far back in time and differing interpretations of local cyclostratigraphic records. The Cretaceous-Paleogene (K/Pg) boundary interval is a good example, where various astronomical and 40Ar/39Ar calibrations have been proposed with varying degrees of agreement. The Denver Basin (Colorado, USA) contains one of the most complete stratigraphic sequences across the K/Pg boundary in the world, preserving evidence of bolide impact as well as biotic extinction and recovery in a thick stratigraphic package that is accessible by both core and outcrop. We present a series of high-precision U-Pb age determinations from interbedded volcanic ash deposits within a tightly constrained magnetobiostratigraphic framework across the K/Pg boundary in the Denver Basin. This new timeline provides a precise absolute age for the K/Pg boundary, constrains the ages of magnetic polarity Chrons C28 to C30, and provides a direct and independent test of early Paleogene astronomical and 40Ar/39Ar based timescales. Temporal calibration of fossil pollen evidence of the "fern spike" in the Denver Basin shows that plant extinctions peaked within ~50-500 years of the bolide impact and primary productivity recovered ~500-5000 years after the impact.

Multi-method investigation of cushion peatlands (

NASA Astrophysics Data System (ADS)

Forbriger, M.; Schittek, K.; Höfle, B.; Siart, C.; Eitel, B.

2012-04-01

This study presents a multi-method and multi-proxy approach for palaeonvironmental investigations in the western andean cordillera of southern Peru (Lucanas province, 14° S) using cushion peatlands as terrestrial geoarchives. The region stretching between the Altiplano and the Peruvian desert in the lowland shares a long term settlement history, in which local cultures adapted to climate change in many different ways. Being one of the most outstanding human remains, the abri below Cerro Llamoca, 4.450 m a.s.l. in the uppermost ranges of the Llamoca peatland catchment area further reveals an occupation history of almost 10.000 years, as revealed by latest archaeological investigations. In remote and highly elevated regions such as the central Andes, cushion peatlands basically represent the only high resolution terrestrial archives suitable for geoarchaeological and palaeoenvironmental studies. Characterized by high accumulation rates, they ideally document environmental changes, particularly at small time intervals. Within the multidisciplinary project 'Andean Transect - Climate Sensitivity of pre-Columbian Man-Environment-Systems' several sediment cores with depths up to 11.5 m b.s. were recovered from the Llamoca peatland. Based on almost 100 AMS 14C-datings they provide a chronology of 8000 years and, thus, offer profound insights into climatic and environmental changes in the study area. While nearly homogeneous peat layers record stable environmental conditions, the heterogeneous granulometric composition of intercalated sediment layers documents several periods of intense geomorphodynamic activity. Due to high resolution geochemical analyses of peat layers (1 cm interval; humification degree, CNS measurements, XRF-scanning), the existence of slight and short-term trends of landscape development during these phases can be identified. Additional pollen, charred particles and plant macrofossil analyses confirm these findings and help reconstructing local vegetation history. High-resolution digital elevation models derived from terrestrial laser scanning (TLS) provide important input data for geomorphologic analyses on current geomorphic processes that can be transferred to former times. Detailed subsurface information obtained by geophysics (electrical resistivity tomography ERT) helped identify the most suitable sampling sites. Information about peat thickness, stratigraphy and depth to bedrock was combined with topographical elevation data, chronometrical outcomes and palaeoenvironmental parameters to generate subsurface models of the study site. The findings allow reconstructing and visualizing the ancient landscape and the stages of peat development, which coincide with pre-Columbian cultural eras.

Comparison of Interferometric Time-Series Analysis Techniques with Implications for Future Mission Design

NASA Astrophysics Data System (ADS)

Werner, C. L.; Wegmuller, U.; Strozzi, T.; Wiesmann, A.

2006-12-01

Principle contributors to the noise in differential SAR interferograms are temporal phase stability of the surface, geometry relating to baseline and surface slope, and propagation path delay variations due to tropospheric water vapor and the ionosphere. Time series analysis of multiple interferograms generated from a stack of SAR SLC images seeks to determine the deformation history of the surface while reducing errors. Only those scatterers within a resolution element that are stable and coherent for each interferometric pair contribute to the desired deformation signal. Interferograms with baselines exceeding 1/3 the critical baseline have substantial geometrical decorrelation for distributed targets. Short baseline pairs with multiple reference scenes can be combined using least-squares estimation to obtain a global deformation solution. Alternately point-like persistent scatterers can be identified in scenes that do not exhibit geometrical decorrelation associated with large baselines. In this approach interferograms are formed from a stack of SAR complex images using a single reference scene. Stable distributed scatter pixels are excluded however due to the presence of large baselines. We apply both point- based and short-baseline methodologies and compare results for a stack of fine-beam Radarsat data acquired in 2002-2004 over a rapidly subsiding oil field near Lost Hills, CA. We also investigate the density of point-like scatters with respect to image resolution. The primary difficulty encountered when applying time series methods is phase unwrapping errors due to spatial and temporal gaps. Phase unwrapping requires sufficient spatial and temporal sampling. Increasing the SAR range bandwidth increases the range resolution as well as increasing the critical interferometric baseline that defines the required satellite orbital tube diameter. Sufficient spatial sampling also permits unwrapping because of the reduced phase/pixel gradient. Short time intervals further reduce the differential phase due to deformation when the deformation is continuous. Lower frequency systems (L- vs. C-Band) substantially improve the ability to unwrap the phase correctly by directly reducing both interferometric phase amplitude and temporal decorrelation.

Department of Defense Precise Time and Time Interval program improvement plan

NASA Technical Reports Server (NTRS)

Bowser, J. R.

1981-01-01

The United States Naval Observatory is responsible for ensuring uniformity in precise time and time interval operations including measurements, the establishment of overall DOD requirements for time and time interval, and the accomplishment of objectives requiring precise time and time interval with minimum cost. An overview of the objectives, the approach to the problem, the schedule, and a status report, including significant findings relative to organizational relationships, current directives, principal PTTI users, and future requirements as currently identified by the users are presented.

A comprehensive assessment of the correlations between field crop yields and commonly used MODIS products

NASA Astrophysics Data System (ADS)

Johnson, David M.

2016-10-01

An exploratory assessment was undertaken to determine the correlation strength and optimal timing of several commonly used Moderate Resolution Imaging Spectroradiometer (MODIS) composited imagery products against crop yields for 10 globally significant agricultural commodities. The crops analyzed included barley, canola, corn, cotton, potatoes, rice, sorghum, soybeans, sugarbeets, and wheat. The MODIS data investigated included the Normalized Difference Vegetation Index (NDVI), Fraction of Photosynthetically Active Radiation (FPAR), Leaf Area Index (LAI), and Gross Primary Production (GPP), in addition to daytime Land Surface Temperature (DLST) and nighttime LST (NLST). The imagery utilized all had 8-day time intervals, but NDVI had a 250 m spatial resolution while the other products were 1000 m. These MODIS datasets were also assessed from both the Terra and Aqua satellites, with their differing overpass times, to document any differences. A follow-on analysis, using the Terra 250 m NDVI data as a benchmark, looked at the yield prediction utility of NDVI at two spatial scales (250 m vs. 1000 m), two time precisions (8-day vs. 16-day), and also assessed the Enhanced Vegetation Index (EVI, at 250 m, 16-day). The analyses spanned the major farming areas of the United States (US) from the summers of 2008-2013 and used annual county-level average crop yield data from the US Department of Agriculture as a basis. All crops, except rice, showed at least some positive correlations to each of the vegetation related indices in the middle of the growing season, with NDVI performing slightly better than FPAR. LAI was somewhat less strongly correlated and GPP weak overall. Conversely, some of the crops, particularly canola, corn, and soybeans, also showed negative correlations to DLST mid-summer. NLST, however, was never correlated to crop yield, regardless of the crop or seasonal timing. Differences between the Terra and Aqua results were found to be minimal. The 1000 m resolution NDVI showed somewhat poorer performance than the 250 m and suggests spatial resolution is helpful but not a necessity. The 8-day versus 16-day NDVI relationships to yields were very similar other than for the temporal precision. Finally, the EVI often showed the very best performance of all the variables, all things considered.

A simulation to study the feasibility of improving the temporal resolution of LAGEOS geodynamic solutions by using a sequential process noise filter

NASA Technical Reports Server (NTRS)

Hartman, Brian Davis

1995-01-01

A key drawback to estimating geodetic and geodynamic parameters over time based on satellite laser ranging (SLR) observations is the inability to accurately model all the forces acting on the satellite. Errors associated with the observations and the measurement model can detract from the estimates as well. These 'model errors' corrupt the solutions obtained from the satellite orbit determination process. Dynamical models for satellite motion utilize known geophysical parameters to mathematically detail the forces acting on the satellite. However, these parameters, while estimated as constants, vary over time. These temporal variations must be accounted for in some fashion to maintain meaningful solutions. The primary goal of this study is to analyze the feasibility of using a sequential process noise filter for estimating geodynamic parameters over time from the Laser Geodynamics Satellite (LAGEOS) SLR data. This evaluation is achieved by first simulating a sequence of realistic LAGEOS laser ranging observations. These observations are generated using models with known temporal variations in several geodynamic parameters (along track drag and the J(sub 2), J(sub 3), J(sub 4), and J(sub 5) geopotential coefficients). A standard (non-stochastic) filter and a stochastic process noise filter are then utilized to estimate the model parameters from the simulated observations. The standard non-stochastic filter estimates these parameters as constants over consecutive fixed time intervals. Thus, the resulting solutions contain constant estimates of parameters that vary in time which limits the temporal resolution and accuracy of the solution. The stochastic process noise filter estimates these parameters as correlated process noise variables. As a result, the stochastic process noise filter has the potential to estimate the temporal variations more accurately since the constraint of estimating the parameters as constants is eliminated. A comparison of the temporal resolution of solutions obtained from standard sequential filtering methods and process noise sequential filtering methods shows that the accuracy is significantly improved using process noise. The results show that the positional accuracy of the orbit is improved as well. The temporal resolution of the resulting solutions are detailed, and conclusions drawn about the results. Benefits and drawbacks of using process noise filtering in this type of scenario are also identified.

High Spectral Resolution Lidar Data

DOE Data Explorer

Eloranta, Ed

2004-12-01

The HSRL provided calibrated vertical profiles of optical depth, backscatter cross section and depoloarization at a wavelength of 532 nm. Profiles were acquired at 2.5 second intervals with 7.5 meter resolution. Profiles extended from an altitude of 100 m to 30 km in clear air. The lidar penetrated to a maximum optical depth of ~ 4 under cloudy conditions. Our data contributed directly to the aims of the M-PACE experiment, providing calibrated optical depth and optical backscatter measurements which were not available from any other instrument.

Cancer growth and its inhibition in terms of coherence.

PubMed

Popp, Fritz-Albert

2009-01-01

It is shown that a molecular origin for growth inhibition is rather unlikely because the cross-sectional area of inhibitory forces in a cell population cannot exceed more than about 10(-8) Dalton. A model of the time dependence of cell number N(t), where t is the time, is based on biophotons and explains without any contradiction to known experimental results growth regulation in terms of the factor a = 1/T, which stimulates the cell division rate dN/dt and the factor b = dT/dN(1/T(2)), which inhibits cell division. It accounts for the total cell division rate dN/dt = aN(t) - bN(2)(t). For adults, T is the coherence time of about 10(6) s, corresponding to the longest lifetime of cell organelles in men, while dT/dN = 10(-7) s corresponds to the resolution time of the cell population which is always the average time interval between two cell loss events. Our model follows a stringently holistic approach to describing a cell population as an entity, regulated by a fully coherent (biophoton) field.

An ISEE 3 high time resolution study of interplanetary parameter correlations with magnetospheric activity

NASA Technical Reports Server (NTRS)

Baker, D. N.; Zwickl, R. D.; Bame, S. J.; Hones, E. W., Jr.; Tsurutani, B. T.; Smith, E. J.; Akasofu, S.-I.

1983-01-01

The coupling between the solar wind and the geomagnetic disturbances was examined using data from the ISEE-3 spacecraft at an earth-sun libration point and ground-based data. One minute data were used to avoid aliasing in determining the internal magnetospheric response to solar wind conditions. Attention was given to the cross-correlations between the geomagnetic index (AE), the total energy dissipation rate (UT), and the solar wind parameters, as well as the spatial and temporal scales on which the magnetosphere reacts to the solar wind conditions. It was considered necessary to characterize the physics of the solar wind-magnetosphere coupling in order to define the requirements for a spacecraft like the ISEE-3 that could be used as a real time monitoring system for predicting storms and substorms. The correlations among all but one parameter were lower during disturbance intervals; UT was highly correlated with all parameters during the disturbed times. An intrinsic 25-40 min delay was detected between interplanetary activity and magnetospheric response in quite times, diminishing to no more than 15 min during disturbed times.

Reducing Surface Clutter in Cloud Profiling Radar Data

NASA Technical Reports Server (NTRS)

Tanelli, Simone; Pak, Kyung; Durden, Stephen; Im, Eastwood

2008-01-01

An algorithm has been devised to reduce ground clutter in the data products of the CloudSat Cloud Profiling Radar (CPR), which is a nadir-looking radar instrument, in orbit around the Earth, that measures power backscattered by clouds as a function of distance from the instrument. Ground clutter contaminates the CPR data in the lowest 1 km of the atmospheric profile, heretofore making it impossible to use CPR data to satisfy the scientific interest in studying clouds and light rainfall at low altitude. The algorithm is based partly on the fact that the CloudSat orbit is such that the geodetic altitude of the CPR varies continuously over a range of approximately 25 km. As the geodetic altitude changes, the radar timing parameters are changed at intervals defined by flight software in order to keep the troposphere inside a data-collection time window. However, within each interval, the surface of the Earth continuously "scans through" (that is, it moves across) a few range bins of the data time window. For each radar profile, only few samples [one for every range-bin increment ((Delta)r = 240 m)] of the surface-clutter signature are available around the range bin in which the peak of surface return is observed, but samples in consecutive radar profiles are offset slightly (by amounts much less than (Delta)r) with respect to each other according to the relative change in geodetic altitude. As a consequence, in a case in which the surface area under examination is homogenous (e.g., an ocean surface), a sequence of consecutive radar profiles of the surface in that area contains samples of the surface response with range resolution (Delta)p much finer than the range-bin increment ((Delta)p << r). Once the high-resolution surface response has thus become available, the profile of surface clutter can be accurately estimated by use of a conventional maximum-correlation scheme: A translated and scaled version of the high-resolution surface response is fitted to the observed low-resolution profile. The translation and scaling factors that optimize the fit in a maximum-correlation sense represent (1) the true position of the surface relative to the sampled surface peak and (2) the magnitude of the surface backscatter. The performance of this algorithm has been tested on CloudSat data acquired over an ocean surface. A preliminary analysis of the test data showed a surface-clutter-rejection ratio over flat surfaces of >10 dB and a reduction of the contaminated altitude over ocean from about 1 km to about 0.5 km (over the ocean). The algorithm has been embedded in CloudSat L1B processing as of Release 04 (July 2007), and the estimated flat surface clutter is removed in L2B-GEOPROF product from the observed profile of reflectivity (see CloudSat product documentation for details and performance at http://www.cloudsat.cira.colostate.edu/ dataSpecs.php?prodid=1).

Microinjections observed by MMS FEEPS in the dusk to midnight region

DOE PAGES

Fennell, Joseph F.; Turner, D. L.; Lemon, C. L.; ...

2016-06-13

Energetic electron injections are commonly observed in the premidnight to dawn regions in association with substorms. However, successive electron injections are generally separated in time by hours and are rarer in the dusk region of the inner magnetosphere. Early MMS energetic electron data taken in the dusk to premidnight regions above ~9 RE show many clusters of electron injections. These injections of 50–400 keV electrons have energy dispersion signatures indicating that they gradient and curvature drifted from earlier local times. We focus on burst rate data starting near 21:00 UT on 6 August 2015. A cluster of ~40 electron injectionsmore » occurred in the following 4 h interval. The highest-resolution data showed that the electrons in the injections were trapped and had bidirectional field-aligned angular distributions. Here, these injection clusters are a new phenomenon in this region of the magnetosphere.« less

Microinjections observed by MMS FEEPS in the dusk to midnight region

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

Fennell, Joseph F.; Turner, D. L.; Lemon, C. L.

Energetic electron injections are commonly observed in the premidnight to dawn regions in association with substorms. However, successive electron injections are generally separated in time by hours and are rarer in the dusk region of the inner magnetosphere. Early MMS energetic electron data taken in the dusk to premidnight regions above ~9 RE show many clusters of electron injections. These injections of 50–400 keV electrons have energy dispersion signatures indicating that they gradient and curvature drifted from earlier local times. We focus on burst rate data starting near 21:00 UT on 6 August 2015. A cluster of ~40 electron injectionsmore » occurred in the following 4 h interval. The highest-resolution data showed that the electrons in the injections were trapped and had bidirectional field-aligned angular distributions. Here, these injection clusters are a new phenomenon in this region of the magnetosphere.« less

Time series analysis of personal exposure to ambient air pollution and mortality using an exposure simulator.

PubMed

Chang, Howard H; Fuentes, Montserrat; Frey, H Christopher

2012-09-01

This paper describes a modeling framework for estimating the acute effects of personal exposure to ambient air pollution in a time series design. First, a spatial hierarchical model is used to relate Census tract-level daily ambient concentrations and simulated exposures for a subset of the study period. The complete exposure time series is then imputed for risk estimation. Modeling exposure via a statistical model reduces the computational burden associated with simulating personal exposures considerably. This allows us to consider personal exposures at a finer spatial resolution to improve exposure assessment and for a longer study period. The proposed approach is applied to an analysis of fine particulate matter of <2.5 μm in aerodynamic diameter (PM(2.5)) and daily mortality in the New York City metropolitan area during the period 2001-2005. Personal PM(2.5) exposures were simulated from the Stochastic Human Exposure and Dose Simulation. Accounting for exposure uncertainty, the authors estimated a 2.32% (95% posterior interval: 0.68, 3.94) increase in mortality per a 10 μg/m(3) increase in personal exposure to PM(2.5) from outdoor sources on the previous day. The corresponding estimates per a 10 μg/m(3) increase in PM(2.5) ambient concentration was 1.13% (95% confidence interval: 0.27, 2.00). The risks of mortality associated with PM(2.5) were also higher during the summer months.

Topology of Innovation Spaces in the Knowledge Networks Emerging through Questions-And-Answers

PubMed Central

Andjelković, Miroslav; Tadić, Bosiljka; Mitrović Dankulov, Marija; Rajković, Milan; Melnik, Roderick

2016-01-01

The communication processes of knowledge creation represent a particular class of human dynamics where the expertise of individuals plays a substantial role, thus offering a unique possibility to study the structure of knowledge networks from online data. Here, we use the empirical evidence from questions-and-answers in mathematics to analyse the emergence of the network of knowledge contents (or tags) as the individual experts use them in the process. After removing extra edges from the network-associated graph, we apply the methods of algebraic topology of graphs to examine the structure of higher-order combinatorial spaces in networks for four consecutive time intervals. We find that the ranking distributions of the suitably scaled topological dimensions of nodes fall into a unique curve for all time intervals and filtering levels, suggesting a robust architecture of knowledge networks. Moreover, these networks preserve the logical structure of knowledge within emergent communities of nodes, labeled according to a standard mathematical classification scheme. Further, we investigate the appearance of new contents over time and their innovative combinations, which expand the knowledge network. In each network, we identify an innovation channel as a subgraph of triangles and larger simplices to which new tags attach. Our results show that the increasing topological complexity of the innovation channels contributes to network’s architecture over different time periods, and is consistent with temporal correlations of the occurrence of new tags. The methodology applies to a wide class of data with the suitable temporal resolution and clearly identified knowledge-content units. PMID:27171149

Continuous Glucose Monitoring in Female NOD Mice Reveals Daily Rhythms and a Negative Correlation With Body Temperature.

PubMed

Korstanje, Ron; Ryan, Jennifer L; Savage, Holly S; Lyons, Bonnie L; Kane, Kevin G; Sukoff Rizzo, Stacey J

2017-09-01

Previous studies with continuous glucose monitoring in mice have been limited to several days or weeks, with the mouse's physical attachment to the equipment affecting behavior and measurements. In the current study, we measured blood glucose and body temperature at 10-second intervals for 12 weeks in a cohort of NOD/ShiLtJ female mice using wireless telemetry. This allowed us to obtain a high-resolution profile of the circadian rhythm of these two parameters and the onset of hyperglycemic development in real time. The most striking observations were the elevated nocturnal concentrations of glucose into the diabetic range days before elevations in diurnal glucose (when glucose concentrations are historically measured) and the strong, negative correlation between elevated blood glucose concentrations and body temperature with a steady decline of the body temperature with diabetes development. Taken together, this technological advancement provides improved resolution in the study of the disease trajectory of diabetes in mouse models, including relevant translatability to the current technologies of continuous glucose monitoring now regularly used in patients. Copyright © 2017 Endocrine Society.

Evidence for parallel consolidation of motion direction and orientation into visual short-term memory.

PubMed

Rideaux, Reuben; Apthorp, Deborah; Edwards, Mark

2015-02-12

Recent findings have indicated the capacity to consolidate multiple items into visual short-term memory in parallel varies as a function of the type of information. That is, while color can be consolidated in parallel, evidence suggests that orientation cannot. Here we investigated the capacity to consolidate multiple motion directions in parallel and reexamined this capacity using orientation. This was achieved by determining the shortest exposure duration necessary to consolidate a single item, then examining whether two items, presented simultaneously, could be consolidated in that time. The results show that parallel consolidation of direction and orientation information is possible, and that parallel consolidation of direction appears to be limited to two. Additionally, we demonstrate the importance of adequate separation between feature intervals used to define items when attempting to consolidate in parallel, suggesting that when multiple items are consolidated in parallel, as opposed to serially, the resolution of representations suffer. Finally, we used facilitation of spatial attention to show that the deterioration of item resolution occurs during parallel consolidation, as opposed to storage. © 2015 ARVO.

A behavioral economic reward index predicts drinking resolutions: moderation revisited and compared with other outcomes.

PubMed

Tucker, Jalie A; Roth, David L; Vignolo, Mary J; Westfall, Andrew O

2009-04-01

Data were pooled from 3 studies of recently resolved community-dwelling problem drinkers to determine whether a behavioral economic index of the value of rewards available over different time horizons distinguished among moderation (n = 30), abstinent (n = 95), and unresolved (n = 77) outcomes. Moderation over 1- to 2-year prospective follow-up intervals was hypothesized to involve longer term behavior regulation processes than abstinence or relapse and to be predicted by more balanced preresolution monetary allocations between short-term and longer term objectives (i.e., drinking and saving for the future). Standardized odds ratios (ORs) based on changes in standard deviation units from a multinomial logistic regression indicated that increases on this "Alcohol-Savings Discretionary Expenditure" index predicted higher rates of abstinence (OR = 1.93, p = .004) and relapse (OR = 2.89, p < .0001) compared with moderation outcomes. The index had incremental utility in predicting moderation in complex models that included other established predictors. The study adds to evidence supporting a behavioral economic analysis of drinking resolutions and shows that a systematic analysis of preresolution spending patterns aids in predicting moderation.

Eight-channel Kirkpatrick-Baez microscope for multiframe x-ray imaging diagnostics in laser plasma experiments.

PubMed

Yi, Shengzhen; Zhang, Zhe; Huang, Qiushi; Zhang, Zhong; Mu, Baozhong; Wang, Zhanshan; Fang, Zhiheng; Wang, Wei; Fu, Sizu

2016-10-01

Because grazing-incidence Kirkpatrick-Baez (KB) microscopes have better resolution and collection efficiency than pinhole cameras, they have been widely used for x-ray imaging diagnostics of laser inertial confinement fusion. The assembly and adjustment of a multichannel KB microscope must meet stringent requirements for image resolution and reproducible alignment. In the present study, an eight-channel KB microscope was developed for diagnostics by imaging self-emission x-rays with a framing camera at the Shenguang-II Update (SGII-Update) laser facility. A consistent object field of view is ensured in the eight channels using an assembly method based on conical reference cones, which also allow the intervals between the eight images to be tuned to couple with the microstrips of the x-ray framing camera. The eight-channel KB microscope was adjusted via real-time x-ray imaging experiments in the laboratory. This paper describes the details of the eight-channel KB microscope, its optical and multilayer design, the assembly and alignment methods, and results of imaging in the laboratory and at the SGII-Update.

Osteoradionecrosis following treatment for head and neck cancer and the effect of radiotherapy dosimetry: the Guy's and St Thomas' Head and Neck Cancer Unit experience.

PubMed

De Felice, Francesca; Thomas, Christopher; Patel, Vinod; Connor, Steve; Michaelidou, Andriana; Sproat, Chris; Kwok, Jerry; Burke, Mary; Reilly, Damien; McGurk, Mark; Simo, Ricard; Lyons, Andrew; Oakley, Richard; Jeannon, Jean-Pierre; Lei, Mary; Urbano, Teresa Guerrero

2016-07-01

To analyze clinical features, dosimetric parameters, and outcomes of osteoradionecrosis (ORN). Thirty-six patients with ORN who had been previously treated with radiotherapy (RT) were retrospectively identified between January 2009 and April 2014. ORN volumes were contoured on planning computed tomography (CT) scans. Near maximum dose (D2%), minimum dose (Dmin), mean dose (Dmean), and percentage of bone volume receiving 50 Gy (V50) were examined. Clinical and dosimetric variables were considered to compare ORN resolution versus ORN persistence. Median interval time from end of RT to development of ORN was 6 months. Of the ORN cases, 61% were located in the mandible. Dmean to affected bone was 57.6 Gy, and 44% had a D2% 65 Gy or greater. Smoking was associated with ORN persistence on univariate analysis, but no factors were found to impact ORN resolution or progression on logistic regression. Prevention strategies for ORN development should be prioritized. Dose-volume parameters could have a role in preventing ORN. Copyright © 2016 Elsevier Inc. All rights reserved.

Simulation studies of improved sounding systems

NASA Technical Reports Server (NTRS)

Yates, H.; Wark, D.; Aumann, H.; Evans, N.; Phillips, N.; Susskind, J.; Mcmillin, L.; Goldman, A.; Chahine, M.; Crone, L.

1989-01-01

Two instrument designs for indirect satellite sounding of the atmosphere in the infrared are represented by the High Resolution Infra-Red Sounder, Model 2 (HIRS-2) and by the Advanced Meteorological Temperature Sounder (AMTS). The relative capabilities of the two instruments were tested by simulating satellite measurements from a group of temperature soundings, allowing the two participants to retrieve the temperature profiles from the simulated data, and comparing the results with the original temperature profiles. Four data sets were produced from radiosondes data extrapolated to a suitable altitude, representing continents and oceans, between 30S and 30N. From the information available, temperature profiles were retrieved by two different methods, statistical regression and inversion of the radiative transfer equation. Results show the consequence of greater spectral purity, concomitant increase in the number of spectral intervals, and the better spatial resolution in partly clouded areas. At the same time, the limitation of the HIRS-2 without its companion instrument leads to some results which should be ignored in comparing the two instruments. A clear superiority of AMTS results is shown.

A calibration procedure for load cells to improve accuracy of mini-lysimeters in monitoring evapotranspiration

NASA Astrophysics Data System (ADS)

Misra, R. K.; Padhi, J.; Payero, J. O.

2011-08-01

SummaryWe used twelve load cells (20 kg capacity) in a mini-lysimeter system to measure evapotranspiration simultaneously from twelve plants growing in separate pots in a glasshouse. A data logger combined with a multiplexer was used to connect all load cells with the full-bridge excitation mode to acquire load-cell signal. Each load cell was calibrated using fixed load within the range of 0-0.8 times the full load capacity of load cells. Performance of all load cells was assessed on the basis of signal settling time, excitation compensation, hysteresis and temperature. Final calibration of load cells included statistical consideration of these effects to allow prediction of lysimeter weights and evapotranspiration over short-time intervals for improved accuracy and sustained performance. Analysis of the costs for the mini-lysimeter system indicates that evapotranspiration can be measured economically at a reasonable accuracy and sufficient resolution with robust method of load-cell calibration.

Time Resolved Near Field Optical Microscopy

NASA Astrophysics Data System (ADS)

Stark, J. B.

1996-03-01

We use broadband pulses to image the carrier dynamics of semiconductor microstructures on a 150 nm spatial scale, with a time resolution of 60 femtoseconds. Etched disks of GaAs/AlGaAs multiple quantum well material, 10 microns in diameter, are excited with a 30 fs pump from a Ti:Sapphire laser, and probed using a near-field optical microscope. The nonlinear transmission of the microdisks is measured using a double-modulation technique, sensitive to transmission changes of 0.0005 within a 150 nm diameter spot on the sample. This spot is scanned to produce an image of the sample. The nonlinear response is produced by the occupation of phase space by the excited distribution. Images of this evolving distribution are collected at time intervals following excitation, measuring the relaxation of carriers at each point in the microdisk. The resulting data can be viewed as a movie of the carrier dynamics of nonequilibrium distributions in excited semiconductor structures. Work done in collaboration with U. Mohideen and R. E. Slusher.

Epochs of phase coherence between El Niño/Southern Oscillation and Indian monsoon

NASA Astrophysics Data System (ADS)

Maraun, D.; Kurths, J.

2005-08-01

We present a modern method used in nonlinear time series analysis to investigate the relation of two oscillating systems with respect to their phases, independently of their amplitudes. We study the difference of the phase dynamics between El Niño/Southern Oscillation (ENSO) and the Indian Monsoon on inter-annual time scales. We identify distinct epochs, especially two intervals of phase coherence, 1886-1908 and 1964-1980, corroborating earlier findings from a new point of view. A significance test shows that the coherence is very unlikely to be the result of stochastic fluctuations. We also detect so far unknown periods of coupling which are invisible to linear methods. These findings suggest that the decreasing correlation during the last decades might be a typical epoch of the ENSO/Monsoon system having occurred repeatedly. The high time resolution of the method enables us to present an interpretation of how volcanic radiative forcing could cause the coupling.

Ratio-based lengths of intervals to improve fuzzy time series forecasting.

PubMed

Huarng, Kunhuang; Yu, Tiffany Hui-Kuang

2006-04-01

The objective of this study is to explore ways of determining the useful lengths of intervals in fuzzy time series. It is suggested that ratios, instead of equal lengths of intervals, can more properly represent the intervals among observations. Ratio-based lengths of intervals are, therefore, proposed to improve fuzzy time series forecasting. Algebraic growth data, such as enrollments and the stock index, and exponential growth data, such as inventory demand, are chosen as the forecasting targets, before forecasting based on the various lengths of intervals is performed. Furthermore, sensitivity analyses are also carried out for various percentiles. The ratio-based lengths of intervals are found to outperform the effective lengths of intervals, as well as the arbitrary ones in regard to the different statistical measures. The empirical analysis suggests that the ratio-based lengths of intervals can also be used to improve fuzzy time series forecasting.

High-resolution ab initio three-dimensional X-ray diffraction microscopy (CXIDB ID 15)

DOE Data Explorer

Chapman, Henry N.

2011-11-15

The file contains 125 images corresponding to different tilts of the sample around the y axis at 1 degree intervals. Each image is the result of 4 exposures merged together. For more details see the citation.

Water level observations from Unmanned Aerial Vehicles (UAVs) for improving probabilistic estimations of interaction between rivers and groundwater

NASA Astrophysics Data System (ADS)

Bandini, Filippo; Butts, Michael; Vammen Jacobsen, Torsten; Bauer-Gottwein, Peter

2016-04-01

Integrated hydrological models are generally calibrated against observations of river discharge and piezometric head in groundwater aquifers. Integrated hydrological models are rarely calibrated against spatially distributed water level observations measured by either in-situ stations or spaceborne platforms. Indeed in-situ observations derived from ground-based stations are generally spaced too far apart to capture spatial patterns in the water surface. On the other hand spaceborne observations have limited spatial resolution. Additionally satellite observations have a temporal resolution which is not ideal for observing the temporal patterns of the hydrological variables during extreme events. UAVs (Unmanned Aerial Vehicles) offer several advantages: i) high spatial resolution; ii) tracking of the water body better than any satellite technology; iii) timing of the sampling merely depending on the operators. In this case study the Mølleåen river (Denmark) and its catchment have been simulated through an integrated hydrological model (MIKE 11-MIKE SHE). This model was initially calibrated against observations of river discharge retrieved by in-situ stations and against piezometric head of the aquifers. Subsequently the hydrological model has been calibrated against dense spatially distributed water level observations, which could potentially be retrieved by UAVs. Error characteristics of synthetic UAV water level observations were taken from a recent proof-of-concept study. Since the technology for ranging water level is under development, UAV synthetic water level observations were extracted from another model of the river with higher spatial resolution (cross sections located every 10 m). This model with high resolution is assumed to be absolute truth for the purpose of this work. The river model with the coarser resolution has been calibrated against the synthetic water level observations through Differential Evolution Adaptive Metropolis (DREAM) algorithm, an efficient global Markov Chain Monte Carlo (MCMC) in high-dimensional spaces. Calibration against water level has demonstrated a significant improvement of the estimation of the exchange flow between groundwater and river branch. Groundwater flux and direction are now better simulated. Reliability and sharpness of the probabilistic forecasts are assessed with the sharpness, the interval skill score (ISS) of the 95{%} confidence interval, and with the root mean square error (RMSE) of the maximum a posteriori probability (MAP). The binary outcome (either gaining or loosing stream) of the flow direction is assessed with Brier score (BS). After water level calibration the sharpness of the estimations is approximately doubled with respect to the model calibrated only against discharge, ISS has improved from 2.4-7to 7.8-8 m^3/s\\cdot m, RMSE from 9.2-8 to 2.4-8 m^3/s\\cdot m^and BS is halved from 0.58 to 0.25.

Importance of the Time Interval between Bowel Preparation and Colonoscopy in Determining the Quality of Bowel Preparation for Full-Dose Polyethylene Glycol Preparation

PubMed Central

Kim, Tae Kyung; Kim, Hyung Wook; Kim, Su Jin; Ha, Jong Kun; Jang, Hyung Ha; Hong, Young Mi; Park, Su Bum; Choi, Cheol Woong; Kang, Dae Hwan

2014-01-01

Background/Aims The quality of bowel preparation (QBP) is the important factor in performing a successful colonoscopy. Several factors influencing QBP have been reported; however, some factors, such as the optimal preparation-to-colonoscopy time interval, remain controversial. This study aimed to determine the factors influencing QBP and the optimal time interval for full-dose polyethylene glycol (PEG) preparation. Methods A total of 165 patients who underwent colonoscopy from June 2012 to August 2012 were prospectively evaluated. The QBP was assessed using the Ottawa Bowel Preparation Scale (Ottawa) score according to several factors influencing the QBP were analyzed. Results Colonoscopies with a time interval of 5 to 6 hours had the best Ottawa score in all parts of the colon. Patients with time intervals of 6 hours or less had the better QBP than those with time intervals of more than 6 hours (p=0.046). In the multivariate analysis, the time interval (odds ratio, 1.897; 95% confidence interval, 1.006 to 3.577; p=0.048) was the only significant contributor to a satisfactory bowel preparation. Conclusions The optimal time was 5 to 6 hours for the full-dose PEG method, and the time interval was the only significant contributor to a satisfactory bowel preparation. PMID:25368750

Interresponse Time Structures in Variable-Ratio and Variable-Interval Schedules

ERIC Educational Resources Information Center

Bowers, Matthew T.; Hill, Jade; Palya, William L.

2008-01-01

The interresponse-time structures of pigeon key pecking were examined under variable-ratio, variable-interval, and variable-interval plus linear feedback schedules. Whereas the variable-ratio and variable-interval plus linear feedback schedules generally resulted in a distinct group of short interresponse times and a broad distribution of longer…

Neural Mechanisms Underlying the Cost of Task Switching: An ERP Study

PubMed Central

Li, Ling; Wang, Meng; Zhao, Qian-Jing; Fogelson, Noa

2012-01-01

Background When switching from one task to a new one, reaction times are prolonged. This phenomenon is called switch cost (SC). Researchers have recently used several kinds of task-switching paradigms to uncover neural mechanisms underlying the SC. Task-set reconfiguration and passive dissipation of a previously relevant task-set have been reported to contribute to the cost of task switching. Methodology/Principal Findings An unpredictable cued task-switching paradigm was used, during which subjects were instructed to switch between a color and an orientation discrimination task. Electroencephalography (EEG) and behavioral measures were recorded in 14 subjects. Response-stimulus interval (RSI) and cue-stimulus interval (CSI) were manipulated with short and long intervals, respectively. Switch trials delayed reaction times (RTs) and increased error rates compared with repeat trials. The SC of RTs was smaller in the long CSI condition. For cue-locked waveforms, switch trials generated a larger parietal positive event-related potential (ERP), and a larger slow parietal positivity compared with repeat trials in the short and long CSI condition. Neural SC of cue-related ERP positivity was smaller in the long RSI condition. For stimulus-locked waveforms, a larger switch-related central negative ERP component was observed, and the neural SC of the ERP negativity was smaller in the long CSI. Results of standardized low resolution electromagnetic tomography (sLORETA) for both ERP positivity and negativity showed that switch trials evoked larger activation than repeat trials in dorsolateral prefrontal cortex (DLPFC) and posterior parietal cortex (PPC). Conclusions/Significance The results provide evidence that both RSI and CSI modulate the neural activities in the process of task-switching, but that these have a differential role during task-set reconfiguration and passive dissipation of a previously relevant task-set. PMID:22860090

Reduced Short- and Long-Latency Afferent Inhibition Following Acute Muscle Pain: A Potential Role in the Recovery of Motor Output.

PubMed

Burns, Emma; Chipchase, Lucinda Sian; Schabrun, Siobhan May

2016-02-13

. Corticomotor output is reduced in response to acute muscle pain, yet the mechanisms that underpin this effect remain unclear. Here the authors investigate the effect of acute muscle pain on short-latency afferent inhibition, long-latency afferent inhibition, and long-interval intra-cortical inhibition to determine whether these mechanisms could plausibly contribute to reduced motor output in pain. . Observational same subject pre-post test design. . Neurophysiology research laboratory. . Healthy, right-handed human volunteers (n = 22, 9 male; mean age ± standard deviation, 22.6 ± 7.8 years). . Transcranial magnetic stimulation was used to assess corticomotor output, short-latency afferent inhibition, long-latency afferent inhibition, and long-interval intra-cortical inhibition before, during, immediately after, and 15 minutes after hypertonic saline infusion into right first dorsal interosseous muscle. Pain intensity and quality were recorded using an 11-point numerical rating scale and the McGill Pain Questionnaire. . Compared with baseline, corticomotor output was reduced at all time points (p = 0.001). Short-latency afferent inhibition was reduced immediately after (p = 0.039), and long-latency afferent inhibition 15 minutes after (p = 0.035), the resolution of pain. Long-interval intra-cortical inhibition was unchanged at any time point (p = 0.36). . These findings suggest short- and long-latency afferent inhibition, mechanisms thought to reflect the integration of sensory information with motor output at the cortex, are reduced following acute muscle pain. Although the functional relevance is unclear, the authors hypothesize a reduction in these mechanisms may contribute to the restoration of normal motor output after an episode of acute muscle pain. © 2016 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Not All Prehospital Time is Equal: Influence of Scene Time on Mortality

PubMed Central

Brown, Joshua B.; Rosengart, Matthew R.; Forsythe, Raquel M.; Reynolds, Benjamin R.; Gestring, Mark L.; Hallinan, William M.; Peitzman, Andrew B.; Billiar, Timothy R.; Sperry, Jason L.

2016-01-01

Background Trauma is time-sensitive and minimizing prehospital (PH) time is appealing. However, most studies have not linked increasing PH time with worse outcomes, as raw PH times are highly variable. It is unclear whether specific PH time patterns affect outcomes. Our objective was to evaluate the association of PH time interval distribution with mortality. Methods Patients transported by EMS in the Pennsylvania trauma registry 2000-2013 with total prehospital time (TPT)≥20min were included. TPT was divided into three PH time intervals: response, scene, and transport time. The number of minutes in each PH time interval was divided by TPT to determine the relative proportion each interval contributed to TPT. A prolonged interval was defined as any one PH interval contributing ≥50% of TPT. Patients were classified by prolonged PH interval or no prolonged PH interval (all intervals<50% of TPT). Patients were matched for TPT and conditional logistic regression determined the association of mortality with PH time pattern, controlling for confounders. PH interventions were explored as potential mediators, and prehospital triage criteria used identify patients with time-sensitive injuries. Results There were 164,471 patients included. Patients with prolonged scene time had increased odds of mortality (OR 1.21; 95%CI 1.02–1.44, p=0.03). Prolonged response, transport, and no prolonged interval were not associated with mortality. When adjusting for mediators including extrication and PH intubation, prolonged scene time was no longer associated with mortality (OR 1.06; 0.90–1.25, p=0.50). Together these factors mediated 61% of the effect between prolonged scene time and mortality. Mortality remained associated with prolonged scene time in patients with hypotension, penetrating injury, and flail chest. Conclusions Prolonged scene time is associated with increased mortality. PH interventions partially mediate this association. Further study should evaluate whether these interventions drive increased mortality because they prolong scene time or by another mechanism, as reducing scene time may be a target for intervention. Level of Evidence IV, prognostic study PMID:26886000

Time interval measurement device based on surface acoustic wave filter excitation, providing 1 ps precision and stability.

PubMed

Panek, Petr; Prochazka, Ivan

2007-09-01

This article deals with the time interval measurement device, which is based on a surface acoustic wave (SAW) filter as a time interpolator. The operating principle is based on the fact that a transversal SAW filter excited by a short pulse can generate a finite signal with highly suppressed spectra outside a narrow frequency band. If the responses to two excitations are sampled at clock ticks, they can be precisely reconstructed from a finite number of samples and then compared so as to determine the time interval between the two excitations. We have designed and constructed a two-channel time interval measurement device which allows independent timing of two events and evaluation of the time interval between them. The device has been constructed using commercially available components. The experimental results proved the concept. We have assessed the single-shot time interval measurement precision of 1.3 ps rms that corresponds to the time of arrival precision of 0.9 ps rms in each channel. The temperature drift of the measured time interval on temperature is lower than 0.5 ps/K, and the long term stability is better than +/-0.2 ps/h. These are to our knowledge the best values reported for the time interval measurement device. The results are in good agreement with the error budget based on the theoretical analysis.

The hard X-ray burst spectrometer on the solar maximum mission

NASA Technical Reports Server (NTRS)

Orwig, L. E.; Frost, K. J.; Dennis, B. R.

1979-01-01

The primary scientific objective of the spectrometer is to provide a greater understanding of the role of energetic electrons in solar flares. This will be achieved by observations of high energy X-rays in the energy range from 20 to 200 keV with time resolution of 0.128s on a continuous basis and as short as 1 ms for limited intervals. The X-ray detector is an actively shielded CsI(Na) crystal with a thickness of 0.635 cm and a sensitive area of 71 sq cm. In the first year after launch, it is expected that approximately 1000 flares above the sensitivity threshold of 0.2 photons/(sq cm s) lasting for one second, will be detected.

A Beat Frequency RF Modulator for Generation of Low Repetition Rate Electron Microbunches for the CEBAF Polarized Source

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

John Musson; Reza Kazimi; Benard Poelker

2007-06-25

Fiber-based drive lasers now produce all of the spin-polarized electron beams at CEBAF/Jefferson Lab. The flexibility of these drive lasers, combined with the existing three-beam CEBAF photoinjector Chopper, provides a means to implement a beat frequency technique to produce long time intervals between individual electron microbunches (tens of nanoseconds) by merely varying the nominal 499 MHz drive laser frequency by < 20%. This submission describes the RF Laser modulator that uses a divider and heterodyne scheme to maintain coherence with the accelerator Master Oscillator (MO), while providing delay resolution in increments of 2ns. Some possible uses for such a beammore » are discussed as well as intended future development.« less

Imaging galectin-3 dependent endocytosis with lattice light-sheet microscopy

NASA Astrophysics Data System (ADS)

Baek, Jongho; Lou, Jieqiong; Coelho, Simao; Lim, Yean Jin; Seidlitz, Silvia; Nicovich, Philip R.; Wunder, Christian; Johannes, Ludger; Gaus, Katharina

2017-04-01

Lattice light-sheet (LLS) microscopy provides ultrathin light sheets of a two-dimensional optical lattice that allows us imaging three-dimensional (3D) objects for hundreds of time points at sub-second intervals and at or below the diffraction limit. Galectin-3 (Gal3), a carbohydrate-binding protein, triggers glycosphingolipid (GSL)-dependent biogenesis of morphologically distinct endocytic vesicles that are cargo specific and clathrin independent. In this study, we apply LLS microscopy to study the dynamics of Gal3 dependent endocytosis in live T cells. This will allow us to observe Gal3-mediated endocytosis at high temporal and excellent 3D spatial resolution, which may shed light on our understanding of the mechanism and physiological function of Gal3-induced endocytosis.

Feasibility of high resolution seismic reflection to improve accuracy of hydrogeologic models in a culturally noisy part of Ventura County, CA, USA

USGS Publications Warehouse

Miller, R.; Black, W.; Miele, M.; Morgan, T.; Ivanov, J.; Xia, J.; Peterie, S.

2011-01-01

A high-resolution seismic reflection investigation mapped reflectors and identified characteristics potentially influencing the interpretation of the hydrogeology underlying a portion of the Oxnard Plain in Ventura County, California. Design and implementation of this study was heavily influenced by high levels of cultural noise from vehicles, power lines, roads, manufacturing facilities, and underground utilities/vaults. Acquisition and processing flows were tailored to this noisy environment and relatively shallow target interval. Layering within both upper and lower aquifer systems was delineated at a vertical resolution potential of around 2.5 m at 350 m depth. ?? 2011 Society of Exploration Geophysicists.

Probabilistic Assessment of Hypobaric Decompression Sickness Treatment Success

NASA Technical Reports Server (NTRS)

Conkin, Johnny; Abercromby, Andrew F. J.; Dervay, Joseph P.; Feiveson, Alan H.; Gernhardt, Michael L.; Norcross, Jason R.; Ploutz-Snyder, Robert; Wessel, James H., III

2014-01-01

The Hypobaric Decompression Sickness (DCS) Treatment Model links a decrease in computed bubble volume from increased pressure (DeltaP), increased oxygen (O2) partial pressure, and passage of time during treatment to the probability of symptom resolution [P(symptom resolution)]. The decrease in offending volume is realized in 2 stages: a) during compression via Boyle's Law and b) during subsequent dissolution of the gas phase via the O2 window. We established an empirical model for the P(symptom resolution) while accounting for multiple symptoms within subjects. The data consisted of 154 cases of hypobaric DCS symptoms along with ancillary information from tests on 56 men and 18 women. Our best estimated model is P(symptom resolution) = 1 / (1+exp(-(ln(Delta P) - 1.510 + 0.795×AMB - 0.00308×Ts) / 0.478)), where (DeltaP) is pressure difference (psid), AMB = 1 if ambulation took place during part of the altitude exposure, otherwise AMB = 0; and where Ts is the elapsed time in mins from start of the altitude exposure to recognition of a DCS symptom. To apply this model in future scenarios, values of DeltaP as inputs to the model would be calculated from the Tissue Bubble Dynamics Model based on the effective treatment pressure: (DeltaP) = P2 - P1 | = P1×V1/V2 - P1, where V1 is the computed volume of a spherical bubble in a unit volume of tissue at low pressure P1 and V2 is computed volume after a change to a higher pressure P2. If 100% ground level O2 (GLO) was breathed in place of air, then V2 continues to decrease through time at P2 at a faster rate. This calculated value of (DeltaP then represents the effective treatment pressure at any point in time. Simulation of a "pain-only" symptom at 203 min into an ambulatory extravehicular activity (EVA) at 4.3 psia on Mars resulted in a P(symptom resolution) of 0.49 (0.36 to 0.62 95% confidence intervals) on immediate return to 8.2 psia in the Multi-Mission Space Exploration Vehicle. The P(symptom resolution) increased to near certainty (0.99) after 2 hrs of GLO at 8.2 psia or with less certainty on immediate pressurization to 14.7 psia [0.90 (0.83 - 0.95)]. Given the low probability of DCS during EVA and the prompt treatment of a symptom with guidance from the model, it is likely that the symptom and gas phase will resolve with minimum resources and minimal impact on astronaut health, safety, and productivity.

Interval Timing Accuracy and Scalar Timing in C57BL/6 Mice

PubMed Central

Buhusi, Catalin V.; Aziz, Dyana; Winslow, David; Carter, Rickey E.; Swearingen, Joshua E.; Buhusi, Mona C.

2010-01-01

In many species, interval timing behavior is accurate—appropriate estimated durations—and scalar—errors vary linearly with estimated durations. While accuracy has been previously examined, scalar timing has not been yet clearly demonstrated in house mice (Mus musculus), raising concerns about mouse models of human disease. We estimated timing accuracy and precision in C57BL/6 mice, the most used background strain for genetic models of human disease, in a peak-interval procedure with multiple intervals. Both when timing two intervals (Experiment 1) or three intervals (Experiment 2), C57BL/6 mice demonstrated varying degrees of timing accuracy. Importantly, both at individual and group level, their precision varied linearly with the subjective estimated duration. Further evidence for scalar timing was obtained using an intraclass correlation statistic. This is the first report of consistent, reliable scalar timing in a sizable sample of house mice, thus validating the PI procedure as a valuable technique, the intraclass correlation statistic as a powerful test of the scalar property, and the C57BL/6 strain as a suitable background for behavioral investigations of genetically engineered mice modeling disorders of interval timing. PMID:19824777

Relating Solar Resource Variability to Cloud Type

NASA Astrophysics Data System (ADS)

Hinkelman, L. M.; Sengupta, M.

2012-12-01

Power production from renewable energy (RE) resources is rapidly increasing. Generation of renewable energy is quite variable since the solar and wind resources that form the inputs are, themselves, inherently variable. There is thus a need to understand the impact of renewable generation on the transmission grid. Such studies require estimates of high temporal and spatial resolution power output under various scenarios, which can be created from corresponding solar resource data. Satellite-based solar resource estimates are the best source of long-term solar irradiance data for the typically large areas covered by transmission studies. As satellite-based resource datasets are generally available at lower temporal and spatial resolution than required, there is, in turn, a need to downscale these resource data. Downscaling in both space and time requires information about solar irradiance variability, which is primarily a function of cloud types and properties. In this study, we analyze the relationship between solar resource variability and satellite-based cloud properties. One-minute resolution surface irradiance data were obtained from a number of stations operated by the National Oceanic and Atmospheric Administration (NOAA) under the Surface Radiation (SURFRAD) and Integrated Surface Irradiance Study (ISIS) networks as well as from NREL's Solar Radiation Research Laboratory (SRRL) in Golden, Colorado. Individual sites were selected so that a range of meteorological conditions would be represented. Cloud information at a nominal 4 km resolution and half hour intervals was derived from NOAA's Geostationary Operation Environmental Satellite (GOES) series of satellites. Cloud class information from the GOES data set was then used to select and composite irradiance data from the measurement sites. The irradiance variability for each cloud classification was characterized using general statistics of the fluxes themselves and their variability in time, as represented by ramps computed for time scales from 10 s to 0.5 hr. The statistical relationships derived using this method will be presented, comparing and contrasting the statistics computed for the different cloud types. The implications for downscaling irradiances from satellites or forecast models will also be discussed.

Application of random coherence order selection in gradient-enhanced multidimensional NMR

NASA Astrophysics Data System (ADS)

Bostock, Mark J.; Nietlispach, Daniel

2016-03-01

Development of multidimensional NMR is essential to many applications, for example in high resolution structural studies of biomolecules. Multidimensional techniques enable separation of NMR signals over several dimensions, improving signal resolution, whilst also allowing identification of new connectivities. However, these advantages come at a significant cost. The Fourier transform theorem requires acquisition of a grid of regularly spaced points to satisfy the Nyquist criterion, while frequency discrimination and acquisition of a pure phase spectrum require acquisition of both quadrature components for each time point in every indirect (non-acquisition) dimension, adding a factor of 2 N -1 to the number of free- induction decays which must be acquired, where N is the number of dimensions. Compressed sensing (CS) ℓ 1-norm minimisation in combination with non-uniform sampling (NUS) has been shown to be extremely successful in overcoming the Nyquist criterion. Previously, maximum entropy reconstruction has also been used to overcome the limitation of frequency discrimination, processing data acquired with only one quadrature component at a given time interval, known as random phase detection (RPD), allowing a factor of two reduction in the number of points for each indirect dimension (Maciejewski et al. 2011 PNAS 108 16640). However, whilst this approach can be easily applied in situations where the quadrature components are acquired as amplitude modulated data, the same principle is not easily extended to phase modulated (P-/N-type) experiments where data is acquired in the form exp (iωt) or exp (-iωt), and which make up many of the multidimensional experiments used in modern NMR. Here we demonstrate a modification of the CS ℓ 1-norm approach to allow random coherence order selection (RCS) for phase modulated experiments; we generalise the nomenclature for RCS and RPD as random quadrature detection (RQD). With this method, the power of RQD can be extended to the full suite of experiments available to modern NMR spectroscopy, allowing resolution enhancements for all indirect dimensions; alone or in combination with NUS, RQD can be used to improve experimental resolution, or shorten experiment times, of considerable benefit to the challenging applications undertaken by modern NMR.

Spatially distributed potential evapotranspiration modeling and climate projections.

PubMed

Gharbia, Salem S; Smullen, Trevor; Gill, Laurence; Johnston, Paul; Pilla, Francesco

2018-08-15

Evapotranspiration integrates energy and mass transfer between the Earth's surface and atmosphere and is the most active mechanism linking the atmosphere, hydrosphsophere, lithosphere and biosphere. This study focuses on the fine resolution modeling and projection of spatially distributed potential evapotranspiration on the large catchment scale as response to climate change. Six potential evapotranspiration designed algorithms, systematically selected based on a structured criteria and data availability, have been applied and then validated to long-term mean monthly data for the Shannon River catchment with a 50m 2 cell size. The best validated algorithm was therefore applied to evaluate the possible effect of future climate change on potential evapotranspiration rates. Spatially distributed potential evapotranspiration projections have been modeled based on climate change projections from multi-GCM ensembles for three future time intervals (2020, 2050 and 2080) using a range of different Representative Concentration Pathways producing four scenarios for each time interval. Finally, seasonal results have been compared to baseline results to evaluate the impact of climate change on the potential evapotranspiration and therefor on the catchment dynamical water balance. The results present evidence that the modeled climate change scenarios would have a significant impact on the future potential evapotranspiration rates. All the simulated scenarios predicted an increase in potential evapotranspiration for each modeled future time interval, which would significantly affect the dynamical catchment water balance. This study addresses the gap in the literature of using GIS-based algorithms to model fine-scale spatially distributed potential evapotranspiration on the large catchment systems based on climatological observations and simulations in different climatological zones. Providing fine-scale potential evapotranspiration data is very crucial to assess the dynamical catchment water balance to setup management scenarios for the water abstractions. This study illustrates a transferable systematic method to design GIS-based algorithms to simulate spatially distributed potential evapotranspiration on the large catchment systems. Copyright © 2018 Elsevier B.V. All rights reserved.

VARIABLE TIME-INTERVAL GENERATOR

DOEpatents

Gross, J.E.

1959-10-31

This patent relates to a pulse generator and more particularly to a time interval generator wherein the time interval between pulses is precisely determined. The variable time generator comprises two oscillators with one having a variable frequency output and the other a fixed frequency output. A frequency divider is connected to the variable oscillator for dividing its frequency by a selected factor and a counter is used for counting the periods of the fixed oscillator occurring during a cycle of the divided frequency of the variable oscillator. This defines the period of the variable oscillator in terms of that of the fixed oscillator. A circuit is provided for selecting as a time interval a predetermined number of periods of the variable oscillator. The output of the generator consists of a first pulse produced by a trigger circuit at the start of the time interval and a second pulse marking the end of the time interval produced by the same trigger circuit.

Correlating Mediterranean shallow water deposits with global Oligocene-Miocene stratigraphy and oceanic events.

PubMed

Reuter, Markus; Piller, Werner E; Brandano, Marco; Harzhauser, Mathias

2013-12-01

Shallow-marine sediment records have the strong potential to display sensitive environmental changes in sedimentary geometries and skeletal content. However, the time resolution of most neritic carbonate records is not high enough to be compared with climatic events as recorded in the deep-sea sediment archives. In order to resolve the paleoceanographic and paleoclimatic changes during the Oligocene-Miocene transition in the Mediterranean shallow water carbonate systems with the best possible time resolution, we re-evaluated the Decontra section on the Maiella Platform (central Apennines, Italy), which acts as a reference for the correlation of Oligocene-Miocene shallow water deposits in the Mediterranean region. The 120-m-thick late Oligocene-late Miocene carbonate succession is composed of larger foraminiferal, bryozoan and corallinacean limestones interlayered with distinct planktonic foraminiferal carbonates representing a mostly outer neritic setting. Integrated multi-proxy and facies analyses indicate that CaCO 3 and total organic carbon contents as well as gamma-ray display only local to regional processes on the carbonate platform and are not suited for stratigraphic correlation on a wider scale. In contrast, new biostratigraphic data correlate the Decontra stable carbon isotope record to the global deep-sea carbon isotope record. This links relative sea level fluctuations, which are reflected by facies and magnetic susceptibility changes, to third-order eustatic cycles. The new integrated bio-, chemo-, and sequence stratigraphic framework enables a more precise timing of environmental changes within the studied time interval and identifies Decontra as an important locality for correlating not only shallow and deep water sediments of the Mediterranean region but also on a global scale.

Clinical performance of a free-breathing spatiotemporally accelerated 3-D time-resolved contrast-enhanced pediatric abdominal MR angiography

PubMed Central

Yousaf, Ufra; Hsiao, Albert; Cheng, Joseph Y.; Alley, Marcus T.; Lustig, Michael; Pauly, John M.; Vasanawala, Shreyas S.

2015-01-01

Background Pediatric contrast-enhanced MR angiography is often limited by respiration, other patient motion and compromised spatiotemporal resolution. Objective To determine the reliability of a free-breathing spatiotemporally accelerated 3-D time-resolved contrast enhanced MR angiography method for depicting abdominal arterial anatomy in young children. Materials and methods With IRB approval and informed consent, we retrospectively identified 27 consecutive children (16 males and 11 females; mean age: 3.8 years, range: 14 days to 8.4 years) referred for contrast enhanced MR angiography at our institution, who had undergone free-breathing spatiotemporally accelerated time-resolved contrast enhanced MR angiography studies. An radio-frequency-spoiled gradient echo sequence with Cartesian variable density k-space sampling and radial view ordering, intrinsic motion navigation and intermittent fat suppression was developed. Images were reconstructed with soft-gated parallel imaging locally low-rank method to achieve both motion correction and high spatiotemporal resolution. Quality of delineation of 13 abdominal arteries in the reconstructed images was assessed independently by two radiologists on a five-point scale. Ninety-five percent confidence intervals of the proportion of diagnostically adequate cases were calculated. Interobserver agreements were also analyzed. Results Eleven out of 13 arteries achieved acceptable image quality (mean score range: 3.9–5.0) for both readers. Fair to substantial interobserver agreement was reached on nine arteries. Conclusion Free-breathing spatiotemporally accelerated 3-D time-resolved contrast enhanced MR angiography frequently yields diagnostic image quality for most abdominal arteries for pediatric contrast enhanced MR angiography. PMID:26040509

Knowledge-based nonuniform sampling in multidimensional NMR.

PubMed

Schuyler, Adam D; Maciejewski, Mark W; Arthanari, Haribabu; Hoch, Jeffrey C

2011-07-01

The full resolution afforded by high-field magnets is rarely realized in the indirect dimensions of multidimensional NMR experiments because of the time cost of uniformly sampling to long evolution times. Emerging methods utilizing nonuniform sampling (NUS) enable high resolution along indirect dimensions by sampling long evolution times without sampling at every multiple of the Nyquist sampling interval. While the earliest NUS approaches matched the decay of sampling density to the decay of the signal envelope, recent approaches based on coupled evolution times attempt to optimize sampling by choosing projection angles that increase the likelihood of resolving closely-spaced resonances. These approaches employ knowledge about chemical shifts to predict optimal projection angles, whereas prior applications of tailored sampling employed only knowledge of the decay rate. In this work we adapt the matched filter approach as a general strategy for knowledge-based nonuniform sampling that can exploit prior knowledge about chemical shifts and is not restricted to sampling projections. Based on several measures of performance, we find that exponentially weighted random sampling (envelope matched sampling) performs better than shift-based sampling (beat matched sampling). While shift-based sampling can yield small advantages in sensitivity, the gains are generally outweighed by diminished robustness. Our observation that more robust sampling schemes are only slightly less sensitive than schemes highly optimized using prior knowledge about chemical shifts has broad implications for any multidimensional NMR study employing NUS. The results derived from simulated data are demonstrated with a sample application to PfPMT, the phosphoethanolamine methyltransferase of the human malaria parasite Plasmodium falciparum.

How does signal fade on photo-stimulable storage phosphor imaging plates when scanned with a delay and what is the effect on image quality?

PubMed

Ang, Dan B; Angelopoulos, Christos; Katz, Jerald O

2006-11-01

The goals of this in vitro study were to determine the effect of signal fading of DenOptix photo-stimulable storage phosphor imaging plates scanned with a delay and to determine the effect on the diagnostic quality of the image. In addition, we sought to correlate signal fading with image spatial resolution and average pixel intensity values. Forty-eight images were obtained of a test specimen apparatus and scanned at 6 delayed time intervals: immediately scanned, 1 hour, 8 hours, 24 hours, 72 hours, and 168 hours. Six general dentists using Vixwin2000 software performed a measuring task to determine the location of an endodontic file tip and root apex. One-way ANOVA with repeated measures was used to determine the effect of signal fading (delayed scan time) on diagnostic image quality and average pixel intensity value. There was no statistically significant difference in diagnostic image quality resulting from signal fading. No difference was observed in spatial resolution of the images. There was a statistically significant difference in the pixel intensity analysis of an 8-step aluminum wedge between immediate scanning and 24-hour delayed scan time. There was an effect of delayed scanning on the average pixel intensity value. However, there was no effect on image quality and raters' ability to perform a clinical identification task. Proprietary software of the DenOptix digital imaging system demonstrates an excellent ability to process a delayed scan time signal and create an image of diagnostic quality.

4D monitoring of actively failing rockslopes

NASA Astrophysics Data System (ADS)

Rosser, Nick; Williams, Jack; Hardy, Richard; Brain, Matthew

2017-04-01

Assessing the conditions which promote rockfall to collapse relies upon detailed monitoring, ideally before, during and immediately after failure. With standard repeat surveys it is common that surveys do not coincide with or capture precursors, or that surveys are widely spaced relative to the timing and duration of driving forces such as storms. As a result gaining insight into the controls on failure and the timescales over which precursors operate remains difficult to establish with certainty, and establishing direct links between environmental conditions and rock-falls, or sequences of events prior to rockfall, remain difficult to define. To address this, we present analysis of a high-frequency 3D laser scan dataset captured using a new permanently installed system developed to constantly monitor actively failing rock slopes. The system is based around a time of flight laser scanner, integrated with and remotely controlled by dedicated controls and analysis software. The system is configured to capture data at 0.1 m spacing across > 22,000 m3 at up to 30 minute intervals. Here we present results captured with this system over a period of 9 months, spanning spring to winter 2015. Our analysis is focussed upon improving the understanding of the nature of small (< 1m^3) rockfalls falling from near vertical rock cliffs. We focus here on the development of a set of algorithms for differencing that trade-off the temporal resolution of frequent surveys (hourly) against high spatial resolution point clouds (< 0.05 m) to enhance the precision of change detection, allowing both deformation and detachments to be monitored through time. From this dataset we derive rockfall volume frequency distributions based upon short-interval surveys, and identify the presence and/or absence of precursors, in what we believe to be the first constant volumetric measurement of rock face erosion. The results hold implications for understanding of rockfall mechanics, but also for how actively eroding surfaces can be monitored at high temporal frequency. Whilst high frequency data is ideal for describing processes that evolve rapidly through time, the cumulative errors that accumulate when monitored changes are dominated by inverse power-law distributed volumes are significant. To conclude we consider the benefits of defining survey frequency on the basis of the changes being detected relative to the accumulation of errors that inevitably arises when comparing high numbers of sequential surveys.

VizieR Online Data Catalog: Low-resolution near-infrared stellar spectra from CIBER (Kim+, 2017)

NASA Astrophysics Data System (ADS)

Kim, M. G.; Lee, H. M.; Arai, T.; Bock, J.; Cooray, A.; Jeong, W.-S.; Kim, S. J.; Korngut, P.; Lanz, A.; Lee, D. H.; Lee, M. G.; Matsumoto, T.; Matsuura, S.; Nam, U. W.; Onishi, Y.; Shirahata, M.; Smidt, J.; Tsumura, K.; Yamamura, I.; Zemcov, M.

2017-06-01

We present flux-calibrated near-infrared spectra of 105 stars from 0.8{<=}λ{<=}1.8μm with spectral resolution 15{<=}λ/Δλ{<=}30 over the range. The Low-Resolution Spectrometer (LRS) is one of the four optical instruments of the Cosmic Infrared Background Experiment (CIBER) payload; the others are a narrowband spectrometer and two wide-field imagers. The LRS is a prism-dispersed spectrometer with five rectangular 5.35°*2.8' slits imaging a 5.8°*5.8° field of view. The detector has 256*256 pixels at a pixel scale of 1.36'*1.36'. CIBER has flown four times (2009 February, 2010 July, 2012 March, and 2013 June) with apogees and total exposure times of over 325km and ~240s, respectively, in the first three flights and of 550km and 335s in the final, non-recovered flight. Due to spurious signal contamination from thermal emission from the shock-heated rocket skin, we do not use the first flight data in this work. The star spectral types are determined by fitting known spectral templates to the measured LRS spectra. We use the Infrared Telescope Facility (IRTF) and Pickles 1998 (Cat. J/PASP/110/863) templates for the SED fitting. The SpeX instrument installed on the IRTF observed stars using a medium-resolution spectrograph (R=2000). The template library contains spectra for 210 cool stars (F to M type) with wavelength coverage from 0.8 to 2.5μm (Cushing 2005ApJ...623.1115C; Rayner 2009ApJS..185..289R). The Pickles library is a synthetic spectral library that combines spectral data from various observations to achieve wavelength coverage from the UV (0.115μm) to the near-infrared (2.5μm). It contains 131 spectral templates for all star types (i.e., O to M type) with a uniform sampling interval of 5Å. (6 data files).

SU-E-J-88: Deformable Registration Using Multi-Resolution Demons Algorithm for 4DCT.

PubMed

Li, Dengwang; Yin, Yong

2012-06-01

In order to register 4DCT efficiently, we propose an improved deformable registration algorithm based on improved multi-resolution demons strategy to improve the efficiency of the algorithm. 4DCT images of lung cancer patients are collected from a General Electric Discovery ST CT scanner from our cancer hospital. All of the images are sorted into groups and reconstructed according to their phases, and eachrespiratory cycle is divided into 10 phases with the time interval of 10%. Firstly, in our improved demons algorithm we use gradients of both reference and floating images as deformation forces and also redistribute the forces according to the proportion of the two forces. Furthermore, we introduce intermediate variable to cost function for decreasing the noise in registration process. At the same time, Gaussian multi-resolution strategy and BFGS method for optimization are used to improve speed and accuracy of the registration. To validate the performance of the algorithm, we register the previous 10 phase-images. We compared the difference of floating and reference images before and after registered where two landmarks are decided by experienced clinician. We registered 10 phase-images of 4D-CT which is lung cancer patient from cancer hospital and choose images in exhalationas the reference images, and all other images were registered into the reference images. This method has a good accuracy demonstrated by a higher similarity measure for registration of 4D-CT and it can register a large deformation precisely. Finally, we obtain the tumor target achieved by the deformation fields using proposed method, which is more accurately than the internal margin (IM) expanded by the Gross Tumor Volume (GTV). Furthermore, we achieve tumor and normal tissue tracking and dose accumulation using 4DCT data. An efficient deformable registration algorithm was proposed by using multi-resolution demons algorithm for 4DCT. © 2012 American Association of Physicists in Medicine.

Simulating Virtual Terminal Area Weather Data Bases for Use in the Wake Vortex Avoidance System (Wake VAS) Prediction Algorithm

NASA Technical Reports Server (NTRS)

Kaplan, Michael L.; Lin, Yuh-Lang

2004-01-01

During the research project, sounding datasets were generated for the region surrounding 9 major airports, including Dallas, TX, Boston, MA, New York, NY, Chicago, IL, St. Louis, MO, Atlanta, GA, Miami, FL, San Francico, CA, and Los Angeles, CA. The numerical simulation of winter and summer environments during which no instrument flight rule impact was occurring at these 9 terminals was performed using the most contemporary version of the Terminal Area PBL Prediction System (TAPPS) model nested from 36 km to 6 km to 1 km horizontal resolution and very detailed vertical resolution in the planetary boundary layer. The soundings from the 1 km model were archived at 30 minute time intervals for a 24 hour period and the vertical dependent variables as well as derived quantities, i.e., 3-dimensional wind components, temperatures, pressures, mixing ratios, turbulence kinetic energy and eddy dissipation rates were then interpolated to 5 m vertical resolution up to 1000 m elevation above ground level. After partial validation against field experiment datasets for Dallas as well as larger scale and much coarser resolution observations at the other 8 airports, these sounding datasets were sent to NASA for use in the Virtual Air Space and Modeling program. The application of these datasets being to determine representative airport weather environments to diagnose the response of simulated wake vortices to realistic atmospheric environments. These virtual datasets are based on large scale observed atmospheric initial conditions that are dynamically interpolated in space and time. The 1 km nested-grid simulated datasets providing a very coarse and highly smoothed representation of airport environment meteorological conditions. Details concerning the airport surface forcing are virtually absent from these simulated datasets although the observed background atmospheric processes have been compared to the simulated fields and the fields were found to accurately replicate the flows surrounding the airport where coarse verification data were available as well as where airport scale datasets were available.

High-resolution meiotic and physical mapping of the Best vitelliform macular dystrophy (VMD2) locus to pericentromeric chromosome 11

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

Weber, B.H.F.; Vogt, G.; Stoehr, H.

1994-12-01

Best vitelliform macular dystrophy (VMD2) has previously been linked to several microsatellite markers from chromosome 11. Subsequently, additional genetic studies have refined the Best disease region to a 3.7-cM interval flanked by markers at D11S903 and PYGM. To further narrow the interval containing the Best disease gene and to obtain an estimate of the physical size of the minimal candidate region, we used a combination of high-resolution PCR hybrid mapping and analysis of recombinant Best disease chromosomes. We identified six markers from within the D11S903-PYGM interval that show no recombination with the defective gene in three multigeneration Best disease pedigrees.more » Our hybrid panel localizes these markers on either side of the centromere on chromosome 11. The closest markers flanking the disease gene are at D11S986 in band p12-11.22 on the short arm and at D11S480 in band q13.2-13.3 on the proximal long arm. This study demonstrates that the physical size of the Best disease region is exceedingly larger than previously estimated from the genetic data, because of the proximity of the defective gene to the centromere of chromosome 11.« less

Wildfires Dynamics in Siberian Larch Forests

NASA Technical Reports Server (NTRS)

Ponomarev, Evgenii I.; Kharuk, Viacheslav I.; Ranson, Kenneth J.

2016-01-01

Wildfire number and burned area temporal dynamics within all of Siberia and along a south-north transect in central Siberia (45deg-73degN) were studied based on NOAA/AVHRR (National Oceanic and Atmospheric Administration/ Advanced Very High Resolution Radiometer) and Terra/MODIS (Moderate Resolution Imaging Spectroradiometer) data and field measurements for the period 1996-2015. In addition, fire return interval (FRI) along the south-north transect was analyzed. Both the number of forest fires and the size of the burned area increased during recent decades (p < 0.05). Significant correlations were found between forest fires, burned areas and air temperature (r = 0.5) and drought index (The Standardized Precipitation Evapotranspiration Index, SPEI) (r = 0.43). Within larch stands along the transect, wildfire frequency was strongly correlated with incoming solar radiation (r = 0.91). Fire danger period length decreased linearly from south to north along the transect. Fire return interval increased from 80 years at 62 N to 200 years at the Arctic Circle (6633' N), and to about 300 years near the northern limit of closed forest stands (about 71+ N). That increase was negatively correlated with incoming solar radiation (r = 0.95). Keywords: wildfires; drought index; larch stands; fire return interval; fire frequency; burned area; climate-induced trends in Siberian wildfires

Identification of Dust Source Regions at High-Resolution and Dynamics of Dust Source Mask over Southwest United States Using Remote Sensing Data

NASA Astrophysics Data System (ADS)

Sprigg, W. A.; Sahoo, S.; Prasad, A. K.; Venkatesh, A. S.; Vukovic, A.; Nickovic, S.

2015-12-01

Identification and evaluation of sources of aeolian mineral dust is a critical task in the simulation of dust. Recently, time series of space based multi-sensor satellite images have been used to identify and monitor changes in the land surface characteristics. Modeling of windblown dust requires precise delineation of mineral dust source and its strength that varies over a region as well as seasonal and inter-annual variability due to changes in land use and land cover. Southwest USA is one of the major dust emission prone zone in North American continent where dust is generated from low lying dried-up areas with bare ground surface and they may be scattered or appear as point sources on high resolution satellite images. In the current research, various satellite derived variables have been integrated to produce a high-resolution dust source mask, at grid size of 250 m, using data such as digital elevation model, surface reflectance, vegetation cover, land cover class, and surface wetness. Previous dust source models have been adopted to produce a multi-parameter dust source mask using data from satellites such as Terra (Moderate Resolution Imaging Spectroradiometer - MODIS), and Landsat. The dust source mask model captures the topographically low regions with bare soil surface, dried-up river plains, and lakes which form important source of dust in southwest USA. The study region is also one of the hottest regions of USA where surface dryness, land use (agricultural use), and vegetation cover changes significantly leading to major changes in the areal coverage of potential dust source regions. A dynamic high resolution dust source mask have been produced to address intra-annual change in the aerial extent of bare dry surfaces. Time series of satellite derived data have been used to create dynamic dust source masks. A new dust source mask at 16 day interval allows enhanced detection of potential dust source regions that can be employed in the dust emission and transport pathways models for better estimation of emission of dust during dust storms, particulate air pollution, public health risk assessment tools and decision support systems.

Hospital factors impact variation in emergency department length of stay more than physician factors.

PubMed

Krall, Scott P; Cornelius, Angela P; Addison, J Bruce

2014-03-01

To analyze the correlation between the many different emergency department (ED) treatment metric intervals and determine if the metrics directly impacted by the physician correlate to the "door to room" interval in an ED (interval determined by ED bed availability). Our null hypothesis was that the cause of the variation in delay to receiving a room was multifactorial and does not correlate to any one metric interval. We collected daily interval averages from the ED information system, Meditech©. Patient flow metrics were collected on a 24-hour basis. We analyzed the relationship between the time intervals that make up an ED visit and the "arrival to room" interval using simple correlation (Pearson Correlation coefficients). Summary statistics of industry standard metrics were also done by dividing the intervals into 2 groups, based on the average ED length of stay (LOS) from the National Hospital Ambulatory Medical Care Survey: 2008 Emergency Department Summary. Simple correlation analysis showed that the doctor-to-discharge time interval had no correlation to the interval of "door to room (waiting room time)", correlation coefficient (CC) (CC=0.000, p=0.96). "Room to doctor" had a low correlation to "door to room" CC=0.143, while "decision to admitted patients departing the ED time" had a moderate correlation of 0.29 (p <0.001). "New arrivals" (daily patient census) had a strong correlation to longer "door to room" times, 0.657, p<0.001. The "door to discharge" times had a very strong correlation CC=0.804 (p<0.001), to the extended "door to room" time. Physician-dependent intervals had minimal correlation to the variation in arrival to room time. The "door to room" interval was a significant component to the variation in "door to discharge" i.e. LOS. The hospital-influenced "admit decision to hospital bed" i.e. hospital inpatient capacity, interval had a correlation to delayed "door to room" time. The other major factor affecting department bed availability was the "total patients per day." The correlation to the increasing "door to room" time also reflects the effect of availability of ED resources (beds) on the patient evaluation time. The time that it took for a patient to receive a room appeared more dependent on the system resources, for example, beds in the ED, as well as in the hospital, than on the physician.

Intact interval timing in circadian CLOCK mutants.

PubMed

Cordes, Sara; Gallistel, C R

2008-08-28

While progress has been made in determining the molecular basis for the circadian clock, the mechanism by which mammalian brains time intervals measured in seconds to minutes remains a mystery. An obvious question is whether the interval-timing mechanism shares molecular machinery with the circadian timing mechanism. In the current study, we trained circadian CLOCK +/- and -/- mutant male mice in a peak-interval procedure with 10 and 20-s criteria. The mutant mice were more active than their wild-type littermates, but there were no reliable deficits in the accuracy or precision of their timing as compared with wild-type littermates. This suggests that expression of the CLOCK protein is not necessary for normal interval timing.

High-resolution genetic linkage mapping, high-temperature tolerance and growth-related quantitative trait locus (QTL) identification in Marsupenaeus japonicus.

PubMed

Lu, Xia; Luan, Sheng; Hu, Long Yang; Mao, Yong; Tao, Ye; Zhong, Sheng Ping; Kong, Jie

2016-06-01

The Kuruma prawn, Marsupenaeus japonicus, is one of the most promising marine invertebrates in the industry in Asia, Europe and Australia. However, the increasing global temperatures result in considerable economic losses in M. japonicus farming. In the present study, to select genetically improved animals for the sustainable development of the Kuruma prawn industry, a high-resolution genetic linkage map and quantitative trait locus (QTL) identification were performed using the RAD technology. The maternal map contained 5849 SNP markers and spanned 3127.23 cM, with an average marker interval of 0.535 cM. Instead, the paternal map contained 3927 SNP markers and spanned 3326.19 cM, with an average marker interval of 0.847 cM. The consensus map contained 9289 SNP markers and spanned 3610.90 cM, with an average marker interval of 0.388 cM and coverage of 99.06 % of the genome. The markers were grouped into 41 linkage groups in the maps. Significantly, negative correlation was detected between high-temperature tolerance (UTT) and body weight (BW). The QTL mapping revealed 129 significant QTL loci for UTT and four significant QTL loci for BW at the genome-wide significance threshold. Among these QTLs, 129 overlapped with linked SNPs, and the remaining four were located in regions between contiguous SNPs. They explained the total phenotypic variance ranging from 8.9 to 12.4 %. Because of a significantly negative correlation between growth and high-temperature tolerance, we demonstrate that this high-resolution linkage map and QTLs would be useful for further marker-assisted selection in the genetic improvement of M. japonicus.

The Anaesthetic-ECT Time Interval in Electroconvulsive Therapy Practice--Is It Time to Time?

PubMed

Gálvez, Verònica; Hadzi-Pavlovic, Dusan; Wark, Harry; Harper, Simon; Leyden, John; Loo, Colleen K

2016-01-01

Because most common intravenous anaesthetics used in ECT have anticonvulsant properties, their plasma-brain concentration at the time of seizure induction might affect seizure expression. The quality of ECT seizure expression has been repeatedly associated with efficacy outcomes. The time interval between the anaesthetic bolus injection and the ECT stimulus (anaesthetic-ECT time interval) will determine the anaesthetic plasma-brain concentration when the ECT stimulus is administered. The aim of this study was to examine the effect of the anaesthetic-ECT time interval on ECT seizure quality and duration. The anaesthetic-ECT time interval was recorded in 771 ECT sessions (84 patients). Right unilateral brief pulse ECT was applied. Anaesthesia given was propofol (1-2 mg/kg) and succinylcholine (0.5-1.0 mg/kg). Seizure quality indices (slow wave onset, amplitude, regularity, stereotypy and post-ictal suppression) and duration were rated through a structured rating scale by a single blinded trained rater. Linear Mixed Effects Models analysed the effect of the anaesthetic-ECT time interval on seizure quality indices, controlling for propofol dose (mg), ECT charge (mC), ECT session number, days between ECT, age (years), initial seizure threshold (mC) and concurrent medication. Longer anaesthetic-ECT time intervals lead to significantly higher quality seizures (p < 0.001 for amplitude, regularity, stereotypy and post-ictal suppression). These results suggest that the anaesthetic-ECT time interval is an important factor to consider in ECT practice. This time interval should be extended to as long as practically possible to facilitate the production of better quality seizures. Close collaboration between the anaesthetist and the psychiatrist is essential. Copyright © 2015 Elsevier Inc. All rights reserved.

Scheduling with Automatic Resolution of Conflicts

NASA Technical Reports Server (NTRS)

Clement, Bradley; Schaffer, Steve

2006-01-01

DSN Requirement Scheduler is a computer program that automatically schedules, reschedules, and resolves conflicts for allocations of resources of NASA s Deep Space Network (DSN) on the basis of ever-changing project requirements for DSN services. As used here, resources signifies, primarily, DSN antennas, ancillary equipment, and times during which they are available. Examples of project-required DSN services include arraying, segmentation, very-long-baseline interferometry, and multiple spacecraft per aperture. Requirements can include periodic reservations of specific or optional resources during specific time intervals or within ranges specified in terms of starting times and durations. This program is built on the Automated Scheduling and Planning Environment (ASPEN) software system (aspects of which have been described in previous NASA Tech Briefs articles), with customization to reflect requirements and constraints involved in allocation of DSN resources. Unlike prior DSN-resource- scheduling programs that make single passes through the requirements and require human intervention to resolve conflicts, this program makes repeated passes in a continuing search for all possible allocations, provides a best-effort solution at any time, and presents alternative solutions among which users can choose.

Software for Improved Extraction of Data From Tape Storage

NASA Technical Reports Server (NTRS)

Cheng, Chiu-Fu

2003-01-01

A computer program has been written to replace the original software of Racal Storeplex Delta tape recorders, which are used at Stennis Space Center. The original software could be activated by a command- line interface only; the present software offers the option of a command-line or graphical user interface. The present software also offers the option of batch-file operation (activation by a file that contains command lines for operations performed consecutively). The present software is also more reliable than was the original software: The original software was plagued by several deficiencies that made it difficult to execute, modify, and test. In addition, when using the original software to extract data that had been recorded within specified intervals of time, the resolution with which one could control starting and stopping times was no finer than about a second (or, in some cases, several seconds). In contrast, the present software is capable of controlling playback times to within 1/100 second of times specified by the user, assuming that the tape-recorder clock is accurate to within 1/100 second.

Software for Improved Extraction of Data From Tape Storage

NASA Technical Reports Server (NTRS)

Cheng, Chiu-Fu

2002-01-01

A computer program has been written to replace the original software of Racal Storeplex Delta tape recorders, which are still used at Stennis Space Center but have been discontinued by the manufacturer. Whereas the original software could be activated by a command-line interface only, the present software offers the option of a command-line or graphical user interface. The present software also offers the option of batch-file operation (activation by a file that contains command lines for operations performed consecutively). The present software is also more reliable than was the original software: The original software was plagued by several deficiencies that made it difficult to execute, modify, and test. In addition, when using the original software to extract data that had been recorded within specified intervals of time, the resolution with which one could control starting and stopping times was no finer than about a second (or, in some cases, several seconds). In contrast, the present software is capable of controlling playback times to within 1/100 second of times specified by the user, assuming that the tape-recorder clock is accurate to within 1/100 second.

Sedimentology and High Resolution Sequence Stratigraphy of the Middle Jurassic Dhruma Formation Carbonates Outcrops in the Central Saudi Arabia

NASA Astrophysics Data System (ADS)

Yousif, Ibrahim; Abdullatif, Osman; Makkawi, Mohammed; Abdulghani, Waleed

2017-04-01

This study investigates the microfacies and sequence stratigraphic frame work of the Middle Jurassic Dhruma Formation in outcrops in central Saudi Arabia. The study contributes to the efforts to understand and enhance local and regional stratigraphic relationship and correlation of the Jurassic carbonate sequences and their significance to reservoir description and prediction in the subsurcae. The study describes and characterizes the sedimentology, microfacies and the stratigraphy of Dhruma Formation from outcrop sections having a total thickness of 70 m. Detailed microfacies and high-resolution stratigraphical analysis were carried out to determine microfacies, cyclicity, sequences and staking pattern. The study revealed ten lithofacies namely: oolitic grainstone,bioclastic oolitic grainstone, oolitic grapestone, bioclastic grainstone,foraminiferal packstone, echinoderm packstone, peloidal packstone to grainstone,skeletal wackestone to packstone, mudstone, and marlstone.These lithofacies were grouped into five lithofacies associations that deposited on a carbonate ramp setting. The depositional environment ranging from low energy lagoonal setting to high-energy shoals and banks to low energy outer ramp setting. Five high-resolution composite sequences have been defined and each sequence is composed at the bottom of intercalated mudstone/wackestone that passing up into grainstone lithofacies.The composite sequences range in thickness from 7 to 15 m, while the parasequences range from 0.5 to 1.5 m. The composite sequences extend laterally for a distance of more than 350 m. The overall composite section shows a shallowing upward succession of the 4th to the 5th order high-resolution sequences.The dominant lithofacies are the grainy ones, which constitute 30%, 50% and 80% of the studied sections. Furthermore, the parasequences thickness and their bio-components are increasing towards the top. The muddy lithofacies intensively affected the vertical continuity of the lower reservoir interval compared to the upper interval. Detailed examination of thin-sections reflects a clear and well-developed reservoir interval in the uppermost part of the section, which is dominated by peloidal packstone and grainstone.The findings of this high-resolution outcrop analog might help to understand and predict lithofacies, stratigraphic heirachies and correlations of Dhruma Formation within the interwell spacing. Moreover, this study might also contribute to better reservoir description and assessment of its quality and architecture in subsurface equivalent reservoirs.

Negative emotion boosts quality of visual working memory representation.

PubMed

Xie, Weizhen; Zhang, Weiwei

2016-08-01

Negative emotion impacts a variety of cognitive processes, including working memory (WM). The present study investigated whether negative emotion modulated WM capacity (quantity) or resolution (quality), 2 independent limits on WM storage. In Experiment 1, observers tried to remember several colors over 1-s delay and then recalled the color of a randomly picked memory item by clicking a best-matching color on a continuous color wheel. On each trial, before the visual WM task, 1 of 3 emotion conditions (negative, neutral, or positive) was induced by having observers to rate the valence of an International Affective Picture System image. Visual WM under negative emotion showed enhanced resolution compared with neutral and positive conditions, whereas the number of retained representations was comparable across the 3 emotion conditions. These effects were generalized to closed-contour shapes in Experiment 2. To isolate the locus of these effects, Experiment 3 adopted an iconic memory version of the color recall task by eliminating the 1-s retention interval. No significant change in the quantity or quality of iconic memory was observed, suggesting that the resolution effects in the first 2 experiments were critically dependent on the need to retain memory representations over a short period of time. Taken together, these results suggest that negative emotion selectively boosts visual WM quality, supporting the dissociable nature quantitative and qualitative aspects of visual WM representation. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Late Permian Forest Composition And Climate Revealed From High-Resolution Carbon Isotopes In Fossil Tree Rings

NASA Astrophysics Data System (ADS)

Gulbranson, E.; Isbell, J. L.; Taylor, E. L.; Ryberg, P. E.; Taylor, T. N.

2012-12-01

Late Permian forests from Antarctica are one of a few examples of polar forest biomes in Earth history. We present a paleoforestry and geochemical study of three contemporaneous Late Permian fossil forests and geochemical analysis of fossil wood specimens from the Permian-Triassic contact in Antarctica. Late Permian paleoforestry analysis suggests that these forests responded to disturbance in exactly the opposite manner as compared to modern boreal forests, with forest thinning and loss of understory vegetation occurring towards areas of disturbance. New high-resolution carbon isotope data from 6 permineralized stumps, 32 tree rings studied in total, indicate that these forests were mixed evergreen and deciduous, but dominated by deciduous trees. Moreover, intra-tree ring and ring-to-ring variation of δ13C values suggest that the Late Permian polar climate maintained wet winters, with precipitation in the austral winter being a factor of three greater than the austral summer. Such seasonality in precipitation implies the development of a temperate-like climate at polar latitudes following the demise of the late Paleozoic ice age. High-resolution carbon isotopes in tree rings in a stratigraphic succession of Late Permian fossil wood to fossil wood at the Permian-Triassic contact indicates that Antarctica experienced a change in precipitation patterns around the time of the Permian-Triassic boundary, marked by intervals of pronounced drying juxtaposed against wetter conditions.

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

Zhang, Yaping; Williams, Brent J.; Goldstein, Allen H.

Here, we present a rapid method for apportioning the sources of atmospheric organic aerosol composition measured by gas chromatography–mass spectrometry methods. Here, we specifically apply this new analysis method to data acquired on a thermal desorption aerosol gas chromatograph (TAG) system. Gas chromatograms are divided by retention time into evenly spaced bins, within which the mass spectra are summed. A previous chromatogram binning method was introduced for the purpose of chromatogram structure deconvolution (e.g., major compound classes) (Zhang et al., 2014). Here we extend the method development for the specific purpose of determining aerosol samples' sources. Chromatogram bins are arrangedmore » into an input data matrix for positive matrix factorization (PMF), where the sample number is the row dimension and the mass-spectra-resolved eluting time intervals (bins) are the column dimension. Then two-dimensional PMF can effectively do three-dimensional factorization on the three-dimensional TAG mass spectra data. The retention time shift of the chromatogram is corrected by applying the median values of the different peaks' shifts. Bin width affects chemical resolution but does not affect PMF retrieval of the sources' time variations for low-factor solutions. A bin width smaller than the maximum retention shift among all samples requires retention time shift correction. A six-factor PMF comparison among aerosol mass spectrometry (AMS), TAG binning, and conventional TAG compound integration methods shows that the TAG binning method performs similarly to the integration method. However, the new binning method incorporates the entirety of the data set and requires significantly less pre-processing of the data than conventional single compound identification and integration. In addition, while a fraction of the most oxygenated aerosol does not elute through an underivatized TAG analysis, the TAG binning method does have the ability to achieve molecular level resolution on other bulk aerosol components commonly observed by the AMS.« less

Processing grounded-wire TEM signal in time-frequency-pseudo-seismic domain: A new paradigm

NASA Astrophysics Data System (ADS)

Khan, M. Y.; Xue, G. Q.; Chen, W.; Huasen, Z.

2017-12-01

Grounded-wire TEM has received great attention in mineral, hydrocarbon and hydrogeological investigations for the last several years. Conventionally, TEM soundings have been presented as apparent resistivity curves as function of time. With development of sophisticated computational algorithms, it became possible to extract more realistic geoelectric information by applying inversion programs to 1-D & 3-D problems. Here, we analyze grounded-wire TEM data by carrying out analysis in time, frequency and pseudo-seismic domain supported by borehole information. At first, H, K, A & Q type geoelectric models are processed using a proven inversion program (1-D Occam inversion). Second, time-to-frequency transformation is conducted from TEM ρa(t) curves to magneto telluric MT ρa(f) curves for the same models based on all-time apparent resistivity curves. Third, 1-D Bostick's algorithm was applied to the transformed resistivity. Finally, EM diffusion field is transformed into propagating wave field obeying the standard wave equation using wavelet transformation technique and constructed pseudo-seismic section. The transformed seismic-like wave indicates that some reflection and refraction phenomena appear when the EM wave field interacts with geoelectric interface at different depth intervals due to contrast in resistivity. The resolution of the transformed TEM data is significantly improved in comparison to apparent resistivity plots. A case study illustrates the successful hydrogeophysical application of proposed approach in recovering water-filled mined-out area in a coal field located in Ye county, Henan province, China. The results support the introduction of pseudo-seismic imaging technology in short-offset version of TEM which can also be an useful aid if integrated with seismic reflection technique to explore possibilities for high resolution EM imaging in future.

Analysis of the variability of extra-tropical cyclones at the regional scale for the coasts of Northern Germany and investigation of their coastal impacts

NASA Astrophysics Data System (ADS)

Schaaf, Benjamin; Feser, Frauke

2015-04-01

The evaluation of long-term changes in wind speeds is very important for the coastal areas and the protection measures. Therefor the wind variability at the regional scale for the coast of Northern Germany shall be analysed. In order to derive changes in storminess it is essential to analyse long, homogeneous meteorological time series. Wind measurements often suffer from inconsistencies which arise from changes in instrumentation, observation method, or station location. Reanalysis data take into account such inhomogeneities of observation data and convert these measurements into a consistent, gridded data set with the same grid spacing and time intervals. This leads to a smooth, homogeneous data set, but with relatively low resolution (about 210 km for the longest reanalysis data set, the NCEP reanalysis starting in 1948). Therefore a high-resolution regional atmospheric model will be used to bring these reanalyses to a higher resolution, using in addition to a dynamical downscaling approach the spectral nudging technique. This method 'nudges' the large spatial scales of the regional climate model towards the reanalysis, while the smaller spatial scales are left unchanged. It was applied successfully in a number of applications, leading to realistic atmospheric weather descriptions of the past. With the regional climate model COSMO-CLM a very high-resolution data set was calculated for the last 67 years, the period from 1948 until now. The model area is North Germany with the coastal area of the North sea and parts of the Baltic sea. This is one of the first model simulations on climate scale with a very high resolution of 2.8 km, so even small scale effects can be detected. With this hindcast-simulation there are numerous options of evaluation. One can create wind climatologies for regional areas such as for the metropolitan region of Hamburg. Otherwise one can investigate individual storms in a case study. With a filtering and tracking program the course of individual storms can be tracked and compared with observations. Also statistical studies can be done and one can calculate percentiles, return periods and other different extreme value statistic variables. Later, with a further nesting simulation, the resolution can be reduced to 1 km for individual areas of interest to analyse small islands (as Foehr or Amrum) and their effects on the atmospheric flow more closely.

US LAND-COVER MONITORING AND DETECTION OF CHANGES IN SCALE AND CONTEXT OF FOREST

EPA Science Inventory

Disparate land-cover mapping programs, previously focused solely on mission-oriented goals, have organized themselves as the Multi-Resolution Land Characteristics (MRLC) Consortium with a unified goal of producing land-cover nationwide at routine intervals. Under MRLC, United Sta...

Impact of small-scale saline tracer heterogeneity on electrical resistivity monitoring in fully and partially saturated porous media: Insights from geoelectrical milli-fluidic experiments

NASA Astrophysics Data System (ADS)

Jougnot, Damien; Jiménez-Martínez, Joaquín; Legendre, Raphaël; Le Borgne, Tanguy; Méheust, Yves; Linde, Niklas

2018-03-01

Time-lapse electrical resistivity tomography (ERT) is a geophysical method widely used to remotely monitor the migration of electrically-conductive tracers and contaminant plumes in the subsurface. Interpretations of time-lapse ERT inversion results are generally based on the assumption of a homogeneous solute concentration below the resolution limits of the tomogram depicting inferred electrical conductivity variations. We suggest that ignoring small-scale solute concentration variability (i.e., at the sub-resolution scale) is a major reason for the often-observed apparent loss of solute mass in ERT tracer studies. To demonstrate this, we developed a geoelectrical milli-fluidic setup where the bulk electric conductivity of a 2D analogous porous medium, consisting of cylindrical grains positioned randomly inside a Hele-Shaw cell, is monitored continuously in time while saline tracer tests are performed through the medium under fully and partially saturated conditions. High resolution images of the porous medium are recorded with a camera at regular time intervals, and provide both the spatial distribution of the fluid phases (aqueous solution and air), and the saline solute concentration field (where the solute consists of a mixture of salt and fluorescein, the latter being used as a proxy for the salt concentration). Effective bulk electrical conductivities computed numerically from the measured solute concentration field and the spatial distributions of fluid phases agree well with the measured bulk conductivities. We find that the effective bulk electrical conductivity is highly influenced by the connectivity of high electrical conductivity regions. The spatial distribution of air, saline tracer fingering, and mixing phenomena drive temporal changes in the effective bulk electrical conductivity by creating preferential paths or barriers for electrical current at the pore-scale. The resulting heterogeneities in the solute concentrations lead to strong anisotropy of the effective bulk electrical conductivity, especially for partially saturated conditions. We highlight how these phenomena contribute to the typically large apparent mass loss observed when conducting field-scale time-lapse ERT.

Remote sensing sensitivity to fire severity and fire recovery

USGS Publications Warehouse

Key, C.H.

2005-01-01

The paper examines fundamental ways that geospatial data on fire severity and recovery are influenced by conditions of the remote sensing. Remote sensing sensitivities are spatial, temporal and radiometric in origin. Those discussed include spatial resolution, the sampling time of year, and time since fire. For standard reference, sensitivities are demonstrated with examples drawn from an archive of burn assessments based on one radiometric index, the differenced Normalized Burn Ratio. Resolution determines the aggregation of fire effects within a pixel (alpha variation), hence defining the detected ecological response, and controlling the ability to determine patchiness and spatial distribution of responses throughout a burn (beta variation). As resolution decreases, alpha variation increases, extracting beta variation from the complexity of the whole burn. Seasonal timing impacts the radiometric quality of data in terms of transmittance, sun angle, and potential for enhanced contrast between responses within burns. Remote sensing sensitivity can degrade during many fire seasons when snow, incomplete burning, hazy conditions, low sun angles, or extended drought are common. Time since fire (lag timing) most notably shapes severity detection through the first-order fire effects evident in survivorship and delayed mortality that emerge by the growth period after fire. The former effects appear overly severe at first, but diminish, as burned vegetation remains viable. Conversely, the latter signals vegetation that appears healthy at first, but is damaged by heat to the extent that it soon dies. Both responses can lead to either over- or under-estimating severity, respectively, depending on fire behavior and pre-fire composition unique to each burned area. Based on implications of such sensitivities, three sampling intervals for short-term burn severity are identified; rapid, initial, and extended assessment, sampled within ca. two weeks, two months, and depending on the ecotype, from three months to one year after fire, respectively. Jointly, remote sensing conditions and the way burns are studied yield different tendencies for data quality and information content that impact the objectives and hypotheses that can be studied. Such considerations can be commonly overlooked, but need to be incorporated especially in comparative studies, and to build long-term reference databases on fire severity and recovery.

Temporal rainfall disaggregation using a multiplicative cascade model for spatial application in urban hydrology

NASA Astrophysics Data System (ADS)

Müller, H.; Haberlandt, U.

2018-01-01

Rainfall time series of high temporal resolution and spatial density are crucial for urban hydrology. The multiplicative random cascade model can be used for temporal rainfall disaggregation of daily data to generate such time series. Here, the uniform splitting approach with a branching number of 3 in the first disaggregation step is applied. To achieve a final resolution of 5 min, subsequent steps after disaggregation are necessary. Three modifications at different disaggregation levels are tested in this investigation (uniform splitting at Δt = 15 min, linear interpolation at Δt = 7.5 min and Δt = 3.75 min). Results are compared both with observations and an often used approach, based on the assumption that a time steps with Δt = 5.625 min, as resulting if a branching number of 2 is applied throughout, can be replaced with Δt = 5 min (called the 1280 min approach). Spatial consistence is implemented in the disaggregated time series using a resampling algorithm. In total, 24 recording stations in Lower Saxony, Northern Germany with a 5 min resolution have been used for the validation of the disaggregation procedure. The urban-hydrological suitability is tested with an artificial combined sewer system of about 170 hectares. The results show that all three variations outperform the 1280 min approach regarding reproduction of wet spell duration, average intensity, fraction of dry intervals and lag-1 autocorrelation. Extreme values with durations of 5 min are also better represented. For durations of 1 h, all approaches show only slight deviations from the observed extremes. The applied resampling algorithm is capable to achieve sufficient spatial consistence. The effects on the urban hydrological simulations are significant. Without spatial consistence, flood volumes of manholes and combined sewer overflow are strongly underestimated. After resampling, results using disaggregated time series as input are in the range of those using observed time series. Best overall performance regarding rainfall statistics are obtained by the method in which the disaggregation process ends at time steps with 7.5 min duration, deriving the 5 min time steps by linear interpolation. With subsequent resampling this method leads to a good representation of manhole flooding and combined sewer overflow volume in terms of hydrological simulations and outperforms the 1280 min approach.

Joint time/frequency-domain inversion of reflection data for seabed geoacoustic profiles and uncertainties.

PubMed

Dettmer, Jan; Dosso, Stan E; Holland, Charles W

2008-03-01

This paper develops a joint time/frequency-domain inversion for high-resolution single-bounce reflection data, with the potential to resolve fine-scale profiles of sediment velocity, density, and attenuation over small seafloor footprints (approximately 100 m). The approach utilizes sequential Bayesian inversion of time- and frequency-domain reflection data, employing ray-tracing inversion for reflection travel times and a layer-packet stripping method for spherical-wave reflection-coefficient inversion. Posterior credibility intervals from the travel-time inversion are passed on as prior information to the reflection-coefficient inversion. Within the reflection-coefficient inversion, parameter information is passed from one layer packet inversion to the next in terms of marginal probability distributions rotated into principal components, providing an efficient approach to (partially) account for multi-dimensional parameter correlations with one-dimensional, numerical distributions. Quantitative geoacoustic parameter uncertainties are provided by a nonlinear Gibbs sampling approach employing full data error covariance estimation (including nonstationary effects) and accounting for possible biases in travel-time picks. Posterior examination of data residuals shows the importance of including data covariance estimates in the inversion. The joint inversion is applied to data collected on the Malta Plateau during the SCARAB98 experiment.

Scanner observations of cool stars from 3400 to 11,000 A.

NASA Technical Reports Server (NTRS)

Fay, T.; Honeycutt, R. K.

1972-01-01

Evaluation of photoelectric scans of the M supergiant alpha Ori and the carbon stars 19 Psc, W Ori, and DS Peg made at 20-A resolution from 3400 to 6000 A and at 40-A resolution from 6000 to 11,000 A. The data are corrected for atmospheric extinction and for the instrumental response to obtain plots of log flux per unit frequency interval versus wavelength. The dominant spectral features are due to C2, CN, and TiO; the variation of these features with spectral class is pointed out.

Intact Interval Timing in Circadian CLOCK Mutants

PubMed Central

Cordes, Sara; Gallistel, C. R.

2008-01-01

While progress has been made in determining the molecular basis for the circadian clock, the mechanism by which mammalian brains time intervals measured in seconds to minutes remains a mystery. An obvious question is whether the interval timing mechanism shares molecular machinery with the circadian timing mechanism. In the current study, we trained circadian CLOCK +/− and −/− mutant male mice in a peak-interval procedure with 10 and 20-s criteria. The mutant mice were more active than their wild-type littermates, but there were no reliable deficits in the accuracy or precision of their timing as compared with wild-type littermates. This suggests that expression of the CLOCK protein is not necessary for normal interval timing. PMID:18602902

Effect of a health system's medical error disclosure program on gastroenterology-related claims rates and costs.

PubMed

Adams, Megan A; Elmunzer, B Joseph; Scheiman, James M

2014-04-01

In 2001, the University of Michigan Health System (UMHS) implemented a novel medical error disclosure program. This study analyzes the effect of this program on gastroenterology (GI)-related claims and costs. This was a review of claims in the UMHS Risk Management Database (1990-2010), naming a gastroenterologist. Claims were classified according to pre-determined categories. Claims data, including incident date, date of resolution, and total liability dollars, were reviewed. Mean total liability incurred per claim in the pre- and post-implementation eras was compared. Patient encounter data from the Division of Gastroenterology was also reviewed in order to benchmark claims data with changes in clinical volume. There were 238,911 GI encounters in the pre-implementation era and 411,944 in the post-implementation era. A total of 66 encounters resulted in claims: 38 in the pre-implementation era and 28 in the post-implementation era. Of the total number of claims, 15.2% alleged delay in diagnosis/misdiagnosis, 42.4% related to a procedure, and 42.4% involved improper management, treatment, or monitoring. The reduction in the proportion of encounters resulting in claims was statistically significant (P=0.001), as was the reduction in time to claim resolution (1,000 vs. 460 days) (P<0.0001). There was also a reduction in the mean total liability per claim ($167,309 pre vs. $81,107 post, 95% confidence interval: 33682.5-300936.2 pre vs. 1687.8-160526.7 post). Implementation of a novel medical error disclosure program, promoting transparency and quality improvement, not only decreased the number of GI-related claims per patient encounter, but also dramatically shortened the time to claim resolution.

Stratigraphic framework for Pliocene paleoclimate reconstruction: The correlation conundrum

USGS Publications Warehouse

Dowsett, H.J.; Robinson, M.M.

2006-01-01

Pre-Holocene paleoclimate reconstructions face a correlation conundrum because complications inherent in the stratigraphic record impede the development of synchronous reconstruction. The Pliocene Research, Interpretation and Synoptic Mapping (PRISM) paleoenvironmental reconstructions have carefully balanced temporal resolution and paleoclimate proxy data to achieve a useful and reliable product and are the most comprehensive pre-Pleistocene data sets available for analysis of warmer-than-present climate and for climate modeling experiments. This paper documents the stratigraphic framework for the mid-Pliocene sea surface temperature (SST) reconstruction of the North Atlantic and explores the relationship between stratigraphic/temporal resolution and various paleoceanographic estimates of SST. The magnetobiostratigraphic framework for the PRISM North Atlantic region is constructed from planktic foraminifer, calcareous nannofossil and paleomagnetic reversal events recorded in deep-sea cores and calibrated to age. Planktic foraminifer census data from multiple samples within the mid-Pliocene yield multiple SST estimates for each site. Extracting a single SST value at each site from multiple estimates, given the limitations of the material and stratigraphic resolution, is problematic but necessary for climate model experiments. The PRISM reconstruction, unprecedented in its integration of many different types of data at a focused stratigraphic interval, utilizes a time slab approach and is based on warm peak average temperatures. A greater understanding of the dynamics of the climate system and significant advances in models now mandate more precise, globally distributed yet temporally synchronous SST estimates than are available through averaging techniques. Regardless of the precision used to correlate between sequences within the midd-Pliocene, a truly synoptic reconstruction in the temporal sense is unlikely. SST estimates from multiple proxies promise to further refine paleoclimate reconstructions but must consider the complications associated with each method, what each proxy actually records, and how these different proxies compare in time-averaged samples.

Assessing very high resolution UAV imagery for monitoring forest health during a simulated disease outbreak

NASA Astrophysics Data System (ADS)

Dash, Jonathan P.; Watt, Michael S.; Pearse, Grant D.; Heaphy, Marie; Dungey, Heidi S.

2017-09-01

Research into remote sensing tools for monitoring physiological stress caused by biotic and abiotic factors is critical for maintaining healthy and highly-productive plantation forests. Significant research has focussed on assessing forest health using remotely sensed data from satellites and manned aircraft. Unmanned aerial vehicles (UAVs) may provide new tools for improved forest health monitoring by providing data with very high temporal and spatial resolutions. These platforms also pose unique challenges and methods for health assessments must be validated before use. In this research, we simulated a disease outbreak in mature Pinus radiata D. Don trees using targeted application of herbicide. The objective was to acquire a time-series simulated disease expression dataset to develop methods for monitoring physiological stress from a UAV platform. Time-series multi-spectral imagery was acquired using a UAV flown over a trial at regular intervals. Traditional field-based health assessments of crown health (density) and needle health (discolouration) were carried out simultaneously by experienced forest health experts. Our results showed that multi-spectral imagery collected from a UAV is useful for identifying physiological stress in mature plantation trees even during the early stages of tree stress. We found that physiological stress could be detected earliest in data from the red edge and near infra-red bands. In contrast to previous findings, red edge data did not offer earlier detection of physiological stress than the near infra-red data. A non-parametric approach was used to model physiological stress based on spectral indices and was found to provide good classification accuracy (weighted kappa = 0.694). This model can be used to map physiological stress based on high-resolution multi-spectral data.

Baseline impedance measured during high-resolution esophageal impedance manometry reliably discriminates GERD patients.

PubMed

Ravi, K; Geno, D M; Vela, M F; Crowell, M D; Katzka, D A

2017-05-01

Baseline impedance measured with ambulatory impedance pH monitoring (MII-pH) and a mucosal impedance catheter detects gastroesophageal reflux disease (GERD). However, these tools are limited by cost or patient tolerance. We investigated whether baseline impedance measured during high-resolution impedance manometry (HRIM) distinguishes GERD patients from controls. Consecutive patients with clinical HRIM and MII-pH testing were identified. Gastroesophageal reflux disease was defined by esophageal pH <4 for ≥5% of both the supine and total study time, whereas controls had an esophageal pH <4 for ≤3% of the study performed off PPI. Baseline impedance was measured over 15 seconds during the landmark period of HRIM and over three 10 minute intervals during the overnight period of MII-pH. Among 29 GERD patients and 26 controls, GERD patients had a mean esophageal acid exposure time of 22.7% compared to 1.2% in controls (P<.0001). Mean baseline impedance during HRIM was lower in GERD (1061 Ω) than controls (2814 Ω) (P<.0001). Baseline mucosal impedance measured during HRIM and MII-pH correlated (r=0.59, P<.0001). High-resolution esophageal manometry baseline impedance had high diagnostic accuracy for GERD, with an area under the curve (AUC) of 0.931 on receiver operating characteristics (ROC) analysis. A HRIM baseline impedance threshold of 1582 Ω had a sensitivity of 86.2% and specificity of 88.5% for GERD, with a positive predictive value of 89.3% and negative predictive value of 85.2%. Baseline impedance measured during HRIM can reliably discriminate GERD patients with at least moderate esophageal acid exposure from controls. This diagnostic tool may represent an accurate, cost-effective, and less invasive test for GERD. © 2016 John Wiley & Sons Ltd.

Software algorithm and hardware design for real-time implementation of new spectral estimator

PubMed Central

2014-01-01

Background Real-time spectral analyzers can be difficult to implement for PC computer-based systems because of the potential for high computational cost, and algorithm complexity. In this work a new spectral estimator (NSE) is developed for real-time analysis, and compared with the discrete Fourier transform (DFT). Method Clinical data in the form of 216 fractionated atrial electrogram sequences were used as inputs. The sample rate for acquisition was 977 Hz, or approximately 1 millisecond between digital samples. Real-time NSE power spectra were generated for 16,384 consecutive data points. The same data sequences were used for spectral calculation using a radix-2 implementation of the DFT. The NSE algorithm was also developed for implementation as a real-time spectral analyzer electronic circuit board. Results The average interval for a single real-time spectral calculation in software was 3.29 μs for NSE versus 504.5 μs for DFT. Thus for real-time spectral analysis, the NSE algorithm is approximately 150× faster than the DFT. Over a 1 millisecond sampling period, the NSE algorithm had the capability to spectrally analyze a maximum of 303 data channels, while the DFT algorithm could only analyze a single channel. Moreover, for the 8 second sequences, the NSE spectral resolution in the 3-12 Hz range was 0.037 Hz while the DFT spectral resolution was only 0.122 Hz. The NSE was also found to be implementable as a standalone spectral analyzer board using approximately 26 integrated circuits at a cost of approximately $500. The software files used for analysis are included as a supplement, please see the Additional files 1 and 2. Conclusions The NSE real-time algorithm has low computational cost and complexity, and is implementable in both software and hardware for 1 millisecond updates of multichannel spectra. The algorithm may be helpful to guide radiofrequency catheter ablation in real time. PMID:24886214