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1

Young Children's Thinking About Decomposition: Early Modeling Entrees to Complex Ideas in Science  

NASA Astrophysics Data System (ADS)

This study was part of a multi-year project on the development of elementary students' modeling approaches to understanding the life sciences. Twenty-three first grade students conducted a series of coordinated observations and investigations on decomposition, a topic that is rarely addressed in the early grades. The instruction included in-class observations of different types of soil and soil profiling, visits to the school's compost bin, structured observations of decaying organic matter of various kinds, study of organisms that live in the soil, and models of environmental conditions that affect rates of decomposition. Both before and after instruction, students completed a written performance assessment that asked them to reason about the process of decomposition. Additional information was gathered through one-on-one interviews with six focus students who represented variability of performance across the class. During instruction, researchers collected video of classroom activity, student science journal entries, and charts and illustrations produced by the teacher. After instruction, the first-grade students showed a more nuanced understanding of the composition and variability of soils, the role of visible organisms in decomposition, and environmental factors that influence rates of decomposition. Through a variety of representational devices, including drawings, narrative records, and physical models, students came to regard decomposition as a process, rather than simply as an end state that does not require explanation.

Ero-Tolliver, Isi; Lucas, Deborah; Schauble, Leona

2013-01-01

2

Intermediate Phases Observed During Decomposition of LiBH4  

SciTech Connect

Lithium tetrahydridoboranate is among the materials with the highest hydrogen content and has great potential as a possible H2-storage material, although, the release and uptake of H2 is not fully understood. In this work, LiBH4 was studied by in situ synchrotron radiation powder X-ray diffraction (PXD) and solid state CP/MAS NMR both at variable temperatures. This study revealed two new phases observed during dehydrogenation of LiBH4. Phase I is hexagonal, a = 4.93(2) and c = 13.47(3) Angstroms and is observed in the temperature range {approx}200-300 C, and phase II is orthorhombic, a = 8.70(1), b = 5.44(1) and c = 4.441(8) Angstroms and is observed in the temperature range {approx}300-400 C applying a constant heating rate of 5 C/min. Apparently, I transforms into II, e.g. at a constant temperature of T = 265 C after 5 h. Furthermore, a third phase, III, is observed in the temperature range RT to 70 C, and is caused by a reaction between LiBH4 and water vapor from the atmosphere. Hydrogen release is associated with the decomposition of III at ca. 65 C.

Mosegaard,L.; Moller, B.; Jorgensen, J.; Bosenberg, U.; Dornheim, M.; Hanson, J.; Cerenius, Y.; Walker, G.; Jakobsen, H.; et al

2007-01-01

3

Early Pulsar Observations in Australia  

NASA Astrophysics Data System (ADS)

The news about the discovery of the pulsar CP1919 reached Australia soon after the Hewish et al. publication in Nature came out at the end of February 1968. Immediately the Parkes radio telescope was transferred from scheduled observations to observe this new exciting object. Since pulsars have steep spectra, low radio frequency receivers were needed that were not supported by the Radiophysics Division of the CSIRO. As a result I, a staff member of the School of Electrical Engineering, Sydney University, was asked to come with my low-frequency receivers to Parkes and join in the first observations. Later the Molonglo Mills Cross radio telescope showed its suitability to pulsar discoveries and became involved in a number of important discoveries. New additional equipment aimed for the reception of pulsating signals had to be constructed in a hurry. In my talk I will cover the period 1968 to 1970 when I left Sydney for the Max-Planck-Institute in Bonn with its 100-m radio telescope.

Wielebinski, R.

2012-12-01

4

Polar decomposition for attitude determination from vector observations  

NASA Technical Reports Server (NTRS)

This work treats the problem of weighted least squares fitting of a 3D Euclidean-coordinate transformation matrix to a set of unit vectors measured in the reference and transformed coordinates. A closed-form analytic solution to the problem is re-derived. The fact that the solution is the closest orthogonal matrix to some matrix defined on the measured vectors and their weights is clearly demonstrated. Several known algorithms for computing the analytic closed form solution are considered. An algorithm is discussed which is based on the polar decomposition of matrices into the closest unitary matrix to the decomposed matrix and a Hermitian matrix. A somewhat longer improved algorithm is suggested too. A comparison of several algorithms is carried out using simulated data as well as real data from the Upper Atmosphere Research Satellite. The comparison is based on accuracy and time consumption. It is concluded that the algorithms based on polar decomposition yield a simple although somewhat less accurate solution. The precision of the latter algorithms increase with the number of the measured vectors and with the accuracy of their measurement.

Bar-Itzhack, Itzhack Y.

1993-01-01

5

Environmental aspects of VOCs evolved in the early stages of human decomposition  

Microsoft Academic Search

In the present study, the time profile, measured as “accumulation”, of volatile organic compounds (VOCs) produced during the early stages of human decomposition was investigated. A human cadaver was placed in a sealed bag at approximately the 4th day after death. Evolved VOCs were monitored for 24 h by sampling at different time intervals. VOCs produced were analyzed by thermal desorption\\/gas chromatography\\/mass

M. Statheropoulos; A. Agapiou; C. Spiliopoulou; G. C. Pallis; E. Sianos

2007-01-01

6

Observation errors in early historical upper-air observations  

NASA Astrophysics Data System (ADS)

Upper-air observations are a fundamental data source for global atmospheric data products, but uncertainties, particularly in the early years, are not well known. Most of the early observations, which have now been digitized, are prone to a large variety of undocumented uncertainties (errors) that need to be quantified, e.g., for their assimilation in reanalysis projects. We apply a novel approach to estimate errors in upper-air temperature, geopotential height, and wind observations from the Comprehensive Historical Upper-Air Network for the time period from 1923 to 1966. We distinguish between random errors, biases, and a term that quantifies the representativity of the observations. The method is based on a comparison of neighboring observations and is hence independent of metadata, making it applicable to a wide scope of observational data sets. The estimated mean random errors for all observations within the study period are 1.5 K for air temperature, 1.3 hPa for pressure, 3.0 ms-1for wind speed, and 21.4° for wind direction. The estimates are compared to results of previous studies and analyzed with respect to their spatial and temporal variability.

Wartenburger, R.; Brönnimann, S.; Stickler, A.

2013-11-01

7

Early Observations of Supernovae in the Radio  

NASA Astrophysics Data System (ADS)

The field of time domain is going through a revolution. Not only that the current large optical transient surveys allow the discovery of a plethora of supernovae, but an increasing number of supernovae are discovered at a young age, a few hours to a day after explosion. Combined with the new capabilities of radio observatories such as the Jansky Very Large Array, this enables a comprehensive pan-wavelength study of supernovae at an early stage. I will review our results from early radio observations of supernovae in the last year. In short, through our campaign, we were able to rule out a subset of type Ia supernova progenitors, learn about the microphysical parameters of type IIb supernova shockwaves and discover a fast evolving radio supernova. These latest results bode well for future studies of young supernovae.

Horesh, Assaf; Kulkarni, S. R.; Stockdale, C.; Fox, D. B.; Frail, D. A.; Carpenter, J. M.; PTF

2013-01-01

8

Early Observations with The Murchison Widefield Array.  

NASA Astrophysics Data System (ADS)

The Murchison Widefield Array (MWA), one of the demonstrator projects for the Square Kilometre Array, is a next-generation radio telescope being built in Australia. The MWA will study cosmological reionization, the sun, space weather, and time variability of the radio sky between 80 and 300 MHz, with construction of the full 512-tile system to be complete by mid 2010. As is the case with other future large low-frequency arrays, the visibility data rate produced is extremely large; the correlator, with 3000 fully-polarized frequency channels, is 20 GB/s (a few Peta-Bytes/day). It is impractical to store data being generated at this rate, and software is currently being developed to calibrate the visibilities and form images from them in real time. Relatively rapid phase and polarization distortions due to the ionosphere set the cadence for the real-time system, with a complete cycle of calibration, imaging and image de-distortion completed every 8 seconds. Furthermore, the gain and polarization response of the antennas need to be measured and accounted for to reach the challenging dynamic range requirements. The software will run on-site on a high-throughput, real-time computing cluster, at several tera-flops. In the second half of 2008 and early 2009, a series of early observations are being carried out at the MWA site with new generation dipoles, beamformers and receivers. A major objective of these site visits will be to gather information on the antenna primary beams, the sky and the ionosphere, as we prepare to commission a sub-array constructed from the first 32 tiles in mid 2009. Data from these observations will also be used for testing of the real-time calibration and imaging system. In this poster we will present results from these early observations, with an emphasis on some of the main technical challenges.

Mitchell, Daniel; MWA Collaboration

2009-01-01

9

Quantitative analysis of Al-Zn alloys in the early stage of decomposition  

NASA Astrophysics Data System (ADS)

The method of low-angle x-ray scattering is used to perform a detailed analysis of the early stage of decomposition of Al-Zn alloys with 4.41 and 9.41 at. % Zn quenched at different homogenization temperatures. The parameters that characterize the post-quench state of the alloys are determined. It is found that a reduction in the quenching temperature is accompanied by a reduction in the size of the Guinier-Preston (GP) zones and their content of the dissolved element. Here, the density of the zones also decreases. An attempt is made to establish a connection between the parameters of the GP zones and the regions containing closely-spaced lamina formed in the alloys at the homogenization temperature.

Émirbekov, É. T.; Kleshchev, G. V.

1989-08-01

10

Early diagenesis of vascular plant tissues: Lignin and cutin decomposition and biogeochemical implications  

NASA Astrophysics Data System (ADS)

Long-term subaqueous decomposition patterns of five different vascular plant tissues including mangrove leaves and wood ( Avicennia germinans), cypress needles and wood ( Taxodium distichum) and smooth cordgrass ( Spartina alternifora) were followed for a period of 4.0 years, representing the longest litter bag decomposition study to date. All tissues decomposed under identical conditions and final mass losses were 97, 68, 86, 39, and 93%, respectively. Analysis of the lignin component of herbaceous tissues using alkaline CuO oxidation was complicated by the presence of a substantial ester-bound phenol component composed primarily of cinnamyl phenols. To overcome this problem, we introduce a new parameter to represent lignin, ?6. ?6 is comprised only of the six syringyl and vanillyl phenols and was found to be much less sensitive to diagenetic variation than the commonly used parameter ?, which includes the cinnamyl phenols. Patterns of change in lignin content were strongly dependent on tissue type, ranging from 77% enrichment in smooth cordgrass to 6% depletion in cypress needles. In contrast, depletion of cutin was extensive (65-99%) in all herbaceous tissues. Despite these differences in the overall reactivity of lignin and cutin, both macromolecules were extensively degraded during the decomposition period. The long-term decomposition series also provided very useful information about the compositional parameters which are derived from the specific oxidation products of both lignin and cutin. The relative lability of ester-bound cinnamyl phenols compromised their use in parameters to distinguish woody from herbaceous plant debris. The dimer to monomer ratios of lignin-derived phenols indicated that most intermonomeric linkages in lignin degraded at similar rates. Acid to aldehyde ratios of vanillyl and syringyl phenols became elevated, particularly during the latter stages of decomposition supporting the use of these parameters as indicators of diagenetic alteration. Given the observation that cutin-derived source indicator parameters were generally more sensitive to diagenetic alteration than those of lignin, we suggest the distributional patterns of cutin-derived acids and their associated positional isomers may be most useful for tissue-specific distinctions complementing the general categorical information obtained from lignin phenol analysis alone.

Opsahl, Stephen; Benner, Ronald

1995-12-01

11

Chandra Observations of Early-type Galaxies  

NASA Astrophysics Data System (ADS)

We have performed uniform analysis of a sample of 54 nearby, early-type galaxies observed with emph{Chandra}. In this work we present the spectral results for both the diffuse Interstellar Medium, ISM, and low-mass X-ray binaries, LMXBs. We determine the metallicity of the hot ISM in the 22 brightest galaxies and find a narrow range of abundance ratios relative to iron. The average iron metallicity of these bright galaxies is 0.96±0.33 relative to solar. By assuming these enrichment patterns continue to fainter galaxies, we are able to extend accurate ISM modeling down to the faintest galaxies in the sample. The sample of galaxies span 4.5 orders of magnitude in X-ray luminosity starting at L_X=10(38) erg * s(-1) and the average gas temperature in the sample is 0.58±0.24 keV. We present the X-ray properties of these galaxies scaled to one effective radius as well as radial variations of gas and stellar binary luminosities, and radial variations of gas temperature, metallicity, mass, entropy and density.

Athey, Alex E.

2007-11-01

12

Fungal importance extends beyond litter decomposition in experimental early-successional streams.  

PubMed

Fungi are important decomposers of leaf litter in streams and may have knock-on effects on other microbes and carbon cycling. To elucidate such potential effects, we designed an experiment in outdoor experimental channels simulating sand-bottom streams in an early-successional state. We hypothesized that the presence of fungi would enhance overall microbial activity, accompanied by shifts in the microbial communities associated not only with leaf litter but also with sediments. Fifteen experimental channels received sterile sandy sediment, minimal amounts of leaf litter, and one of four inocula containing either (i) fungi and bacteria, or (ii) bacteria only, or (iii) no microorganisms, or (iv) killed microorganisms. Subsequently, we let water from an early-successional catchment circulate through the channels for 5 weeks. Whole-stream metabolism and microbial respiration associated with leaf litter were higher in the channels inoculated with fungi, reflecting higher fungal activity on leaves. Bacterial communities on leaves were also significantly affected. Similarly, increases in net primary production, sediment microbial respiration and chlorophyll a content on the sediment surface were greatest in the channels receiving a fungal inoculum. These results point to a major role of fungal communities in stream ecosystems beyond the well-established direct involvement in leaf litter decomposition. PMID:22958100

Frossard, Aline; Gerull, Linda; Mutz, Michael; Gessner, Mark O

2012-11-01

13

Decomposition of the wind and nonwind effects on observed year-to-year air quality variation  

NASA Astrophysics Data System (ADS)

in emissions and wind are often identified as the two dominant factors contributing to year-to-year variations in the concentration of primary pollutants. However, because changes in wind and emissions are intertwined, it has been difficult to quantitatively differentiate their effects on air quality directly from observed data. In particular, if the annual mean concentration of pollutants is higher than the previous year, it is difficult to identify whether the deterioration in air quality is caused by wind blowing from more polluted regions or an increase in contributing emissions. In this paper, based on wind and pollution roses, we propose a method to differentiate the effects of wind and nonwind (e.g., emissions) changes using direct observation. An index (L) is first defined to quantify the validity of the linear decomposition. The method is then validated by idealized experiments, numerical experiments, and a 2 year observation data set from an actual emissions control program. Finally, we demonstrate the proposed method by studying long-term particulate matter (PM10) variations in Hong Kong during 2000-2011. We find that for most of the period, the linear decomposition of the changes in annual PM10 is valid (up to 90% confidence) and is dominated by the change in nonwind effects (e.g., emissions), whereas the average absolute effect from the wind variability is about 20%. Sensitivity analyses also suggest that our method should work in any location as long as the observed wind and pollution data have sufficient duration and resolution to resolve the corresponding wind and pollution roses.

Li, Ying; Lau, Alexis; Wong, Agnes; Fung, Jimmy

2014-05-01

14

An Early Astronomical Observation by John Goodricke  

NASA Astrophysics Data System (ADS)

John Goodricke (1764-1786) is one of the most intriguing and enigmatic figures in the history of astronomy. Deaf from the age of five, his observations of the light variation of Algol brought him acclaim and the Copley Medal of the Royal Society by the age of nineteen. Together with his neighbor, mentor, and distant relative Edward Pigott, he went on to discover and quantify the light variations of other stars, including Delta Cephei. Goodricke's careful accounts of his observations, and their accuracy, remain a model of clear scientific thinking and reporting. His final derived value for the time between eclipse minima for Algol, for example, is within eight seconds of the modern value. Goodricke's astronomical observing career is generally thought to have begun with his return to his family home in York in 1781 at the age of seventeen. His school mathematics notebook and workbook from the Warrington Academy, however, contains a detailed drawing of the sky which suggest that he was already a knowledgable observer by the age of fifteen. This drawing is presented and interpreted.

French, Linda M.

2009-12-01

15

The Early Years: Developing Observation Skills  

NSDL National Science Digital Library

We typically know children are learning when they are able to make sense of an object's materials or a situation that was previously a bit mysterious and communicate what they have figured out. But what about observing? One of the process skills listed in

Ashbrook, Peggy

2010-10-01

16

Some observations on early military anaesthesia.  

PubMed

Although anaesthesia was discovered in 1846, pain relief had been used for many years previously. Opium, mandragora, and Indian hemp amongst others have been used since the earliest times as alluded to by many of the classical writers. The use of refrigeration anaesthesia is known to have been recommended a millennium ago although it never had much usage. Very soon after the introduction of ether anaesthesia, it was recommended for military use and the first use by the American forces was in Buena Vista early in 1847 and then again at Vera Cruz. Pirogoff taught and used ether anaesthesia on active service with the Russian forces in the Caucasus in the summer of 1847. Meanwhile Spencer Wells, who was serving with the Royal Navy in Malta, was the first British service medical officer recorded to have used anaesthesia. He went on to write up a series of 106 anaesthetics. The Danes were probably next to use anaesthesia in battle using chloroform in 1848. However, it was not until the Crimean War that anaesthesia began to play an important part in battle surgery with many anaesthetics being given with varying results. The War of the Rebellion was the next war in which anaesthesia was important and the first one in which proper statistics were kept allowing useful analysis. Anaesthesia had irrevocably found its place in battlefield surgery. PMID:16800222

Houghton, I T

2006-06-01

17

SOAR remote observing: tactics and early results  

NASA Astrophysics Data System (ADS)

Travel from North America to the 4.1m SOAR telescope atop Cerro Pachon exceeds $1000, and takes >16 hours door to door (20+ hours typically). SOAR aims to exploit best seeing, requiring dynamic scheduling that is impossible to accomplish when catering to peripatetic astronomers. According to technical arguments at www.peakoil.org, we are near the peak rate of depleting world petroleum, so can expect travel costs to climb sharply. With the telecom bubble's glut of optical fiber, we can transmit data more efficiently than astronomers and "observe remotely". With data compression, less than half of the 6 Mbps bandwidth shared currently by SOAR and CTIO is enough to enable a high-fidelity observing presence for SOAR partners in North America, Brazil, and Chile. We discuss access from home by cable modem/DSL link.

Cecil, Gerald N.; Crain, J. Adam

2004-09-01

18

The Early Years: Observing With Magnifiers  

NSDL National Science Digital Library

Inspire your students to become detailed observers by encouraging the use of magnifiers. Magnification can make us see an object with new understanding. Rachel Carson said, "Some of nature's most exquisite handiwork is on a miniature scale, as anyone knows who has applied a magnifying glass to a snowflake" (Carson 1965). The lesson described here uses interesting objects to give children a reason to learn to use a magnifier.

Ashbrook, Peggy

2008-02-01

19

Unimolecular Thermal Decomposition of Phenol and d5-Phenol: Direct Observation of Cyclopentadiene Formation via Cyclohexadienone  

SciTech Connect

The pyrolyses of phenol and d{sub 5}-phenol (C{sub 6}H{sub 5}OH and C{sub 6}D{sub 5}OH) have been studied using a high temperature, microtubular ({mu}tubular) SiC reactor. Product detection is via both photon ionization (10.487 eV) time-of-flight mass spectrometry and matrix isolation infrared spectroscopy. Gas exiting the heated reactor (375 K-1575 K) is subject to a free expansion after a residence time in the {mu}tubular reactor of approximately 50-100 {micro}s. The expansion from the reactor into vacuum rapidly cools the gas mixture and allows the detection of radicals and other highly reactive intermediates. We find that the initial decomposition steps at the onset of phenol pyrolysis are enol/keto tautomerization to form cyclohexadienone followed by decarbonylation to produce cyclopentadiene; C{sub 6}H{sub 5}OH {yields} c-C{sub 6}H{sub 6} = O {yields} c-C{sub 5}H{sub 6} + CO. The cyclopentadiene loses a H atom to generate the cyclopentadienyl radical which further decomposes to acetylene and propargyl radical; c-C{sub 5}H{sub 6} {yields} c-C{sub 5}H{sub 5} + H {yields} HC {triple_bond} CH + HCCCH{sub 2}. At higher temperatures, hydrogen loss from the PhO-H group to form phenoxy radical followed by CO ejection to generate the cyclopentadienyl radical likely contributes to the product distribution; C{sub 6}H{sub 5}O-H {yields} C{sub 6}H{sub 5}O + H {yields} c-C{sub 5}H{sub 5} + CO. The direct decarbonylation reaction remains an important channel in the thermal decomposition mechanisms of the dihydroxybenzenes. Both catechol (o-HO-C{sub 6}H{sub 4}-OH) and hydroquinone (p-HO-C{sub 6}H{sub 4}-OH) are shown to undergo decarbonylation at the onset of pyrolysis to form hydroxycyclopentadiene. In the case of catechol, we observe that water loss is also an important decomposition channel at the onset of pyrolysis.

Scheer, A. M.; Mukarakate, C.; Robichaud, D. J.; Nimlos, M. R.; Carstensen, H. H.; Barney, E. G.

2012-01-28

20

An Early Observation of a Nearby Supernova  

NASA Astrophysics Data System (ADS)

The X-ray emission of supernovae is a young field with relatively little data. The possible connection of supernovae with GRBs has been tantalizing since the occurrence of SN1998bw. The debate over that source continues. Observations of SN2002ap may go a long way to settling some of the debate. In addition, the X-ray emission of Type Ic supernova other than SN1998bw is based on the single detection of SN1994I in M51. X-rays provide information about the circumstellar ejecta as the out- going shock runs into matter from previous phases of mass loss. A reverse shock is created which generates low-energy X-rays (~1 keV) while the outgoing shock generates harder events. The X-rays probe the circumstellar matter and will provide measures of abundances. The X-ray light curve provides a measure of the matter distribution. (Ref for SN: Schlegel 1995, Reports Prog in Physics, 58, 1375)

Schlegel, Eric

2001-09-01

21

Singlet oxygen generated from the decomposition of peroxymonocarbonate and its observation with chemiluminescence method.  

PubMed

The decomposition of peroxymonocarbonate (HCO(4)(-)) has been investigated by flow-injection chemiluminescence (CL) method. An ultraweak CL was observed during mixing the bicarbonate and hydrogen peroxide solution in organic cosolvent. An appropriate amount of fluorescent organic compounds, such as dichlorofluorescein (DCF), was added to the HCO(4)(-) solution, a strong CL was recorded. Based on studies of the spectrum of fluorescence, CL and UV-vis spectra, electron spin trapping (ESR) technique, mass spectra (MS) and comparison with H(2)O(2)/hypochlorite (ClO(-)) and H(2)O(2)/molybdate (MoO(4)(-)) systems, the CL mechanism was proposed. The reaction is initiated by unimolecular homolysis of the peroxo O-O bond in HO-OCOO(-) molecule. It was suggested that the bond rearrangement within radicals yield superoxide ion (O(2)(*-)). The interaction of superoxide ion with perhydroxyl radical produces singlet oxygen ((1)O(2)). The energy transfers from singlet oxygen to DCF forming an excited energy acceptor (DCF*). Luminescence (lambda(max)=509 nm) was emitted during the relaxation of the energy acceptor to the ground state. PMID:18996044

Lin, Jin-Ming; Liu, Meilin

2009-02-01

22

Preliminary observations of the decomposition of crown-of-thorns starfish, Acanthaster planci (L.)  

Microsoft Academic Search

The rate of decomposition of 67 crown-of-thorns starfish was monitored over 7–9 days on 2 reefs of the Great Barrier Reef in 7 permanent quadrats in different depths and habitats. The pattern of decomposition was similar in all quadrats irrespective of the site or depth. Many different organisms, including crown-of-thorns starfish, fed on or scavenged the remains. Despite this activity

P. J. Moran

1992-01-01

23

Microscopic observations of X-ray and gamma-ray induced decomposition of ammonium perchlorate crystals  

NASA Technical Reports Server (NTRS)

The X-ray and gamma-ray induced decomposition of ammonium perchlorate was studied by optical, transmission, and scanning electron microscopy. This material is a commonly used oxidizer in solid propellents which could be employed in deep-space probes, and where they will be subjected to a variety of radiations for as long as ten years. In some respects the radiation-induced damage closely resembles the effects produced by thermal decomposition, but in other respects the results differ markedly. Similar radiation and thermal effects include the following: (1) irregular or ill-defined circular etch pits are formed in both cases; (2) approximately the same size pits are produced; (3) the pit density is similar; (4) the c face is considerably more reactive than the m face; and (5) most importantly, many of the etch pits are aligned in crystallographic directions which are the same for thermal or radiolytic decomposition. Thus, dislocations play an important role in the radiolytic decomposition process.

Herley, P. J.; Levy, P. W.

1972-01-01

24

Early Decomposition in Visual Word Recognition: Dissociating Morphology, Form, and Meaning  

ERIC Educational Resources Information Center

The role of morphological, semantic, and form-based factors in the early stages of visual word recognition was investigated across different SOAs in a masked priming paradigm, focusing on English derivational morphology. In a first set of experiments, stimulus pairs co-varying in morphological decomposability and in semantic and orthographic…

Marslen-Wilson, William D.; Bozic, Mirjana; Randall, Billi

2008-01-01

25

TEMPORAL SIGNATURES OF AIR QUALITY OBSERVATIONS AND MODEL OUTPUTS: DO TIME SERIES DECOMPOSITION METHODS CAPTURE RELEVANT TIME SCALES?  

EPA Science Inventory

Time series decomposition methods were applied to meteorological and air quality data and their numerical model estimates. Decomposition techniques express a time series as the sum of a small number of independent modes which hypothetically represent identifiable forcings, thereb...

26

Bacterial decomposition of coral mucus as evaluated by long-term and quantitative observation  

NASA Astrophysics Data System (ADS)

Coral mucus released from Acropora formosa and Montipora digitata was incubated with bacteria under dark conditions for 1 year to evaluate the quantitative degradability. All the mucus samples showed a similar decomposition pattern: about 80% of total organic carbon (TOC) in the mucus was mineralized within 1 month, while some mucus was slowly decomposed over the 1 year. Regression analysis using an exponential curve considering three degradability pools (labile, semilabile, and refractory) fitted the changes of the TOC concentrations very well ( r 2 > 0.99). Compiling the data on the two coral species, the labile organic C in the coral mucus had mineralization rates of 10-18% d-1 and accounted for 79-87% of the initial TOC in the mucus. Semilabile organic C had mineralization rates of 0.3-1.6% d-1 and accounted for 11-18% of the initial TOC. Refractory organic C accounted for 6% at most. These results suggest that not all coral mucus is rapidly decomposed by bacteria but some mucus remains as semilabile and refractory organic matter for several months.

Tanaka, Y.; Ogawa, H.; Miyajima, T.

2011-06-01

27

Acquiring Comprehensive Observations using an Integrated Sensorweb for Early Warning  

NASA Technical Reports Server (NTRS)

As an integrated observing strategy, the concept of sensorweb for Earth observations is appealing in many aspects. For instance, by increasing the spatial and temporal coverage of observations from space and other vantage points, one can eventually aid in increasing the accuracy of the atmospheric models which are precursor to hurricane track prediction, volcanic eruption forecast, and trajectory path of transcontinental transport of dust, harmful nuclear and chemical plumes. In reality, there is little analysis'available in terms of benefits, costs and optimized set of sensors needed to make these necessary observations. This is a complex problem that must be carefully studied and balanced over many boundaries such as science, defense, early warning security, and surveillance. Simplistically, the sensorweb concept from the technological point of view alone has a great appeal in the defense, early warning and security applications. In fact, it can be relatively less expensive in per unit cost as opposed to building and deploying it for the scientific use. However, overall observing approach should not be singled out and aligned somewhat . orthogonally to serve a particular need. On the other hand, the sensorweb should be designed and deployed to serve multiple subject areas and customers simultaneously; and can behave as directed measuring systems for both science and operational entities. Sensorweb can be designed to act as expert systems, and/or also provide a dedicated integrated surveillance network. Today, there is no system in the world that is fully integrated in terms of reporting timely multiple hazards warnings, computing the lass of life and property damage estimates, and is also designed to cater to everyone's needs. It is not an easier problem to undertake and more so is not practically solvable. At this time due to some recent events in the world, the scientific community, social scientists, and operational agencies are more cognizant and getting together to address such colossal problems. Increasing our knowledge of the home planet, via amplified set of observations, is certainly a right step in a right direction. Furthermore, this is a pre-requisite in understanding multiple hazard phenomena's. This paper examines various sensorweb options and observing architectures that can be useful specifically in addressing some of these complex issues. The ultimate goal is to serve the society by providing potential natural hazards information to the decision makers in the most expeditious manner so they can prepare themselves to mitigate potential risks to human life, livestock and property.

Habib, Shahid; Ambrose, Steve

2006-01-01

28

Acquiring Comprehensive Observations using an integrated Sensorweb for Early Warning  

NASA Technical Reports Server (NTRS)

As an integrated observing strategy, the concept of sensorweb for Earth observations is appealing in many aspects. For instance, by increasing the spatial and temporal coverage of observations from space and other vantage points, one can eventually aid in increasing the accuracy of the atmospheric models which are precursor to hurricane track prediction, volcanic eruption forecast, and trajectory path of transcontinental transport of dust, harmful nuclear and chemical plumes. In reality, there is little analysis'available in terms of benefits, costs and optimized set of sensors needed to make these necessary observations. This is a complex problem that must be carefully studied and balanced over many boundaries such as science, defense, early warning, security, and surveillance. Simplistically, the sensorweb concept from the technological point of view alone has a great appeal in the defense, early warning and security applications. In fact, it can be relatively less expensive in per unit cost as opposed to building and deploying it for the scientific use. However, overall observing approach should not be singled out and aligned somewhat orthogonally to serve a particular need. On the other hand, the sensorweb should be designed and deployed to serve multiple subject areas and customers simultaneously; and can behave as directed measuring systems for both science and operational entities. Sensorweb can be designed to act as expert systems, and/or also provide a dedicated integrated surveillance network. Today, there is no system in the world that is fully integrated in terms of reporting timely multiple hazards warnings, computing the loss of life and property damage estimates, and is also designed to cater to everyone's needs. It is not an easier problem to undertake and more so is not practically solvable. At this time due to some recent events in the world, the scientific community, social scientists, and operational agencies are more cognizant and getting together to address such colossal problems. Increasing our knowledge of the home planet, via amplified set of observations, is certainly a right step in a right direction. Furthermore, this is a pre-requisite in understanding multiple hazard phenomena's. This paper examines various sensorweb options and observing architectures that can be useful specifically in addressing some of these complex issues. The ultimate goal is to serve the society by providing potential natural hazards information to the decision makers in the most expeditious manner so they can prepare themselves to mitigate potential risks to human life, livestock and property.

Habib, Shahid; Ambrose, Steve

2006-01-01

29

A longitudinal observation of early pulmonary responses to cotton dust  

PubMed Central

Aims: To examine early adverse pulmonary effects of exposure to cotton dust, and to identify potential risk factors, including atopy for pulmonary responses to cotton dust. Methods: Spirometry, methacholine challenge testing, and questionnaire; performed among 101 non-smoking newly hired textile workers at baseline (prior to starting work), and at 3, 12, and 18 months after starting work. Concentrations of airborne cotton dust in various work areas were measured at each follow up survey using vertical elutriators. Results: The incidence of non-specific respiratory symptoms was 8% at three months, then diminished afterwards. Substantial acute cross shift drops in FEV1 at each follow up survey, and longitudinal declines in FVC and FEV1 after 12 months of exposure were observed. Airway responsiveness to methacholine increased with follow up time, and was more pronounced among atopics. Increasing airway responsiveness was strongly correlated with cross shift drops in FEV1. In addition, one or more respiratory symptoms at three months was significantly, and pre-existing atopy marginally significantly, associated with cross shift drops in FEV1 after adjusting for other covariates and confounders. Conclusion: Results suggest that non-specific respiratory symptoms, decreasing lung function, and increasing airway responsiveness are early pulmonary responses to cotton dust. In addition, the occurrence of respiratory symptoms and increasing airway responsiveness, as well as atopy, may be important predictors for acute changes in lung function among cotton textile workers.

Wang, X; Pan, L; Zhang, H; Sun, B; Dai, H; Christiani, D

2003-01-01

30

Self-healing slip pulses driven by thermal decomposition: Towards identifying dynamic weakening mechanisms in seismic observations  

NASA Astrophysics Data System (ADS)

Seismological observations indicate that earthquake ruptures commonly propagate as self-healing slip pulses, with slip duration at any location on the fault being much shorter than the total event duration [Heaton 1990]. Theoretical work has linked these slip pulses to low values of the background driving stress on the fault [Zheng and Rice 1998]. Recent experiments [Han et al. 2007;Brantut et al. 2008] have shown that fault materials may thermally decompose during shear. These endothermic reactions release pore fluid, leading to an increase in pore pressure and a decrease in temperature [Sulem and Famin 2009]. An Arrhenius kinetic controls the reaction rate, and dynamic weakening only occurs when the temperature reaches a critical temperature triggering the reaction. This abrupt change is in sharp contrast with thermal pressurization where the pore pressure increases smoothly with slip. Previous theoretical studies of thermal decomposition have focused on simple mechanical systems with imposed slip rates [Sulem and Famin 2009], or coupling to a spring-slider model [Brantut et al. 2011]. We present the first solutions to couple thermal decomposition with dynamic rupture, extending the model in Garagash [2012] to solve for self-healing slip pulses. For a range of driving stresses there are two possible slip pulses, compared with a single solution for thermal pressurization alone. One solution corresponds to small slip and a low temperature rise that precludes the reaction; the other is a larger slip solution with weakening due to thermal pressurization at the rupture tip, and weakening due to thermal decomposition in the middle of the pulse. A dramatic drop in fault strength accompanies the onset of the reaction, leading to peak slip rates coinciding with the onset of the reaction. For thermal pressurization alone the maximum strain rate always occurs at the rupture tip, and depends sensitively on the driving stress. Thermal decomposition is identified by slower rupture speeds, longer slip duration and more dramatic strength drops. The peak slip rates occur away from the rupture tip, and are insensitive to changes in the driving stress. For deeper events the ambient temperature is higher, causing the reaction to initiate earlier, and the peak slip rate to move towards the rupture tip. Often the total slip in a pulse is linked to a critical slip required to activate the reaction, suggesting a decrease in slip with depth. Our results could also be linked to observed variations in fault zone mineralogy, with different reactions activated on different faults. Since the peak slip rate is achieved at the onset of reaction, maximum pore pressure generation by thermal pressurization coincides with the maximum generation by thermal decomposition, leading to pore pressures exceeding the normal compressive stress on the fault. One possible mechanism to cap the pore pressure is to allow the permeability to increase with the pore pressure [Wibberley and Shimamoto 2003], enhancing healing by hydraulic diffusion at the trailing edge of the pulse. This leads to slip pulses with shorter slip durations and higher rupture velocities.

Platt, J. D.; Viesca, R. C.; Garagash, D.

2012-12-01

31

Early Australian Optical and Radio Observations of Centaurus A  

NASA Astrophysics Data System (ADS)

The discovery of the radio source Centaurus A and its optical counterpart NGC 5128 were important landmarks in the history of Australian astronomy. NGC 5128 was first observed in August 1826 by James Dunlop during a survey of southern objects at the Parramatta Observatory, west of the settlement at Sydney Cove. The observatory had been founded a few years earlier by Thomas Brisbane, the new governor of the British colony of New South Wales. Just over 120 years later, John Bolton, Gordon Stanley and Bruce Slee discovered the radio source Centaurus A at the Dover Heights field station in Sydney, operated by CSIRO's Radiophysics Laboratory (the forerunner to CSIRO Astronomy and Space Sciences). This paper will describe this early historical work and summarize further studies of Centaurus A by other Radiophysics groups up to 1960.

Robertson, Peter; Cozens, Glen; Orchiston, Wayne; Slee, Bruce; Wendt, Harry

2010-10-01

32

"Learning Stories"--Crossing Borders: Introducing Qualitative Early Childhood Observation Techniques to Early Childhood Practitioners in Saudi Arabia  

ERIC Educational Resources Information Center

Early childhood education has become a focus of government policy across the world. Part of the present increased interest in early childhood education has been a focus on curriculum frameworks and socio/cultural methods of assessment. Currently, New Zealand has emerged as a world leader in early childhood education, and observation and assessment…

Nyland, Berenice; Alfayez, Shatha

2012-01-01

33

CONSTRAINING PERTURBATIVE EARLY DARK ENERGY WITH CURRENT OBSERVATIONS  

SciTech Connect

In this work, we study a class of early dark energy (EDE) models, in which, unlike in standard dark energy models, a substantial amount of dark energy exists in the matter-dominated era. We self-consistently include dark energy perturbations, and constrain these models using current observations. We consider EDE models in which the dark energy equation of state is at least w{sub m} {approx_gt} -0.1 at early times, which could lead to an EDE density of up to {Omega}{sub DE}(z{sub CMB})= 0.03{Omega}{sub m}(z{sub CMB}). Our analysis shows that marginalizing over the non-DE parameters such as {Omega}{sub m}, H{sub 0}, andn{sub s} , current CMB observations alone can constrain the scale factor of transition from EDE to late-time dark energy to a{sub t} {approx_gt} 0.44 and width of transition to {Delta}{sub t} {approx_lt} 0.37. The equation of state at present is somewhat weakly constrained to w{sub 0} {approx_lt} -0.6, if we allow H{sub 0} < 60 km s{sup -1} Mpc{sup -1}. Taken together with other observations, such as SNe, Hubble Space Telescope, and Sloan Digital Sky Survey luminous red galaxies, w{sub 0} is constrained much more tightly to w{sub 0} {approx_lt} -0.9, while redshift of transition and width of transition are also tightly constrained to a{sub t} {approx_lt} 0.19 and{Delta}{sub t} {approx_lt} 0.21. The evolution of the equation of state for EDE models is thus tightly constrained to {Lambda}CDM-like behavior at low redshifts. Incorrectly assuming dark energy perturbations to be negligible leads to different constraints on the equation of state parameters-w{sub 0} {approx_lt} -0.8, a{sub t} {approx_lt} 0.33, and{Delta}{sub t} {approx_lt} 0.31, thus highlighting the necessity of self-consistently including dark energy perturbations in the analysis. If we allow the spatial curvature to be a free parameter, then the constraints are relaxed to w{sub 0} {approx_lt} -0.77, a{sub t} {approx_lt} 0.35, and{Delta}{sub t} {approx_lt} 0.35 with -0.014 < {Omega}{sub {kappa}} < 0.031 for CMB + other observations. For perturbed EDE models, the 2{sigma} lower limit on {sigma}{sub 8} ({sigma}{sub 8} {>=} 0.59) is much lower than that in {Lambda}CDM ({sigma}{sub 8} {>=} 0.72), thus raising the interesting possibility of discriminating EDE from {Lambda}CDM using future observations such as halo mass functions or the Sunyaev-Zeldovich power spectrum.

Alam, Ujjaini [ISR-1, ISR Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

2010-05-10

34

Decomposition of the observed surface temperature with the Multi-channel Singular-Spectrum Analysis.  

NASA Astrophysics Data System (ADS)

Climate of the twentieth century is shaped by its natural variability and response to the anthropogenic activity. Therefore to predict the future climate, response of the climate to greenhouse-gas concentrations has to be well understood. As such response may be masked by natural climate oscillations, it is important to separate those components. In this study, Multi-channel Singular-Spectrum Analysis (M-SSA) is applied to the available observational data sets. Those data sets are global fields of surface/sea surface temperature: Met Office HadCRUT4, HadISST and Reynolds OI. With an application of M-SSA, four oscillatory components were found to explain large part of temperature variability. Time scale of derived components varies from an annual to interdecadal. Significant components resemble features of some already identified climate signals, like Atlantic Multidecadal Oscillation, which influences both the Atlantic and North Pacific. Additional analysis is made to assess the physical relevancy of the Pacific Decadal Oscillation (PDO). We test the hypothesis, whether PDO index can be reconstructed with derived oscillatory components. Further analysis aims to discuss statistical significance, physical relevancy of all derived modes and capability of the method to separate natural signal from anthropogenic one in the short and noisy time series.

Barcikowska, Monika; Knutson, Tom

2014-05-01

35

Measurements of physical properties of gas hydrates and in situ observations of formation and decomposition processes via Raman spectroscopy and X-ray diffraction  

Microsoft Academic Search

Gas hydrate properties and phase transition kinetics were studied using Raman spectroscopic and X-ray diffraction methods. These techniques have the advantage of measuring physical properties such as crystal structure, gas composition, and cage occupancy of gas molecules without decomposing the sample. In situ observations using these techniques are indicative of formation and decomposition processes in gas hydrates. Raman spectroscopy is

T. Uchida; S. Takeya; L. D. Wilson; C. A. Tulk; J. A. Ripmeester; J. Nagao; T. Ebinuma; H. Narita

2003-01-01

36

Implementing Observation Protocols: Lessons for K-12 Education from the Field of Early Childhood  

ERIC Educational Resources Information Center

This report draws from decades of experience using observation in early childhood education, which has implications for administrative decisions, evaluation practices, and policymaking in K-12. Early childhood education has long embraced the value of observing classrooms and teacher-child interactions. In early childhood education the features of…

Pianta, Robert C.

2012-01-01

37

Cumulus clouds - Early aircraft observations and entrainment hypotheses  

NASA Technical Reports Server (NTRS)

The history of cumulus research in the decade following World War II is reviewed in the perspective of the new ideas and advances made during the subsequent generation. Emphasis is placed upon pioneering aircraft measurements, evidence for entrainment, the early model attempts and their attendant controversies.

Simpson, J.

1983-01-01

38

Observations of cloud condensation nuclei in Mt. Huang: instrumentation and early observations  

NASA Astrophysics Data System (ADS)

A new commercial instrument for measuring Cloud Condensation Nuclei (CCN), the Droplet Measurement Technologies Cylindrical Continuous-Flow Streamwise Thermal Gradient CCN Chamber (CFSTGC), installed on Mount Huang meteorological station (30°19'N, 118°14'E, 1840m above sea level) from 16 April to 28 July 2008. This instrument can measure CCN concentrations at supersaturations from 0.1% to 2% (potentially up to 6%), as well as a 1 Hz sampling rate that is sufficient for ground-based or airborne platform operation. The instrument records data continuously at 1-second intervals 24 hours a day. For the 98-day, continuous study the average CCN concentration was found to range between a few hundred and a few thousand nuclei per cm3 at supersaturations between 0.3 and 1%. Diurnal variations were observed, as well as other possible influences, such as wind speed, wind direction and mixing depth. At a constant supersaturation of 0.5% the CCN concentration is typically on the order of 361 to 2297 nuclei per cm3. A description of the instrumentation and early observations are presented and discussed.

Chen, Kui; Yin, Yan; Chen, Chen; Yang, Weifeng; Deng, Wei; Hu, Zhenghua; Wu, Fangfang

2009-07-01

39

Observations of stellar winds in early type stars  

NASA Technical Reports Server (NTRS)

The presented review is mainly concerned with the massive population I stars of spectral type OB and the Wolf-Rayet (WR) class. It is pointed out that stellar winds are a ubiquitous phenomenon among the early type stars. Methods to determine the mass loss rate are discussed, taking into account the UV method, the optical method, the infrared method, and the radio method. Current beliefs about early type stars are considered. It is thought that all have stellar winds. The winds are primarily driven by radiation pressure from the UV lines, but other, as yet unknown factors, may determine the density and hence the rates. The stellar winds are highly ionized, more so than would be inferred from their continuum radiation temperatures. The ionization equilibrium in the winds is affected by local X rays which have been detected by the Einstein satellite. Unresolved issues are also pointed out.

Conti, P. S.

1981-01-01

40

Aggressive early intervention after occupational back injury: Some preliminary observations  

Microsoft Academic Search

An interdisciplinary team managed care intervention model that emphasizes aggressive immediate intervention and early return\\u000a to work in transitional light duty work is presented. This case study focuses on the application of this model for 281 workers\\u000a with occupational back injuries. Historically, these injuries have been found to be disproportionately expensive. Outcomes\\u000a such as cost of treatment, return to work,

Leonard N. Matheson; Richard G. Brophy

1997-01-01

41

Early development of spasticity following stroke: a prospective, observational trial  

PubMed Central

This study followed a cohort of 103 patients at median 6 days, 6 and 16 weeks after stroke and recorded muscle tone, pain, paresis, Barthel Index and quality of life score (EQ-5D) to identify risk-factors for development of spasticity. 24.5% of stroke victims developed an increase of muscle tone within 2 weeks after stroke. Patients with spasticity had significantly higher incidences of pain and nursing home placement and lower Barthel and EQ-5D scores than patients with normal muscle tone. Early predictive factors for presence of severe spasticity [modified Ashworth scale score (MAS) ?3] at final follow-up were moderate increase in muscle tone at baseline and/or first follow-up (MAS = 2), low Barthel Index at baseline, hemispasticity, involvement of more than two joints at first follow-up, and paresis at any assessment point. The study helps to identify patients at highest risk for permanent and severe spasticity, and advocates for early treatment in this group.

Schelosky, Ludwig D.; Scott, Jeffrey; Christe, Walter; Faiss, Jurgen H.; Mueller, Jorg

2010-01-01

42

LRO LAMP: Experiment Description, Observation Status, And Early Results.  

NASA Astrophysics Data System (ADS)

LAMP is an Extreme/Far ultraviolet (UV) imaging spectrograph operating in lunar orbit aboard the NASA Lunar Reconnaissance Orbiter (LRO). LRO arrived in lunar orbit in July, 2009. LAMP's primary objective is to search for evidence of exposed polar frosts in permanently shadowed regions; its secondary objectives are to explore the UV reflectivity characteristics of the lunar surface and to study the lunar atmosphere. At the time of this abstract submission, LAMP has been turned on in lunar orbit but has not yet begun its data collections; those collections will begin in August. We will describe the LAMP instrument and investigation, show first light and other early datasets, and describe some initial results.

Stern, S. Alan; Gladstone, R. R.; Retherford, K. R.; Parker, J. W.; Slater, D. C.; Davis, M. W.; Black, R. K.; Greathouse, T. K.; Versteeg, M.; Persson, K. B.; Kaufman, D. E.; Egan, A. F.; Hurley, D.; Feldman, P. D.; Pryor, W. R.

2009-09-01

43

An Observational Study of the Interactions of Socially Withdrawn/Anxious Early Adolescents and Their Friends  

ERIC Educational Resources Information Center

Background: The friendships of socially withdrawn/anxious children and early adolescents have been found to lack critical rewarding qualities. Observational research may help elucidate the obstacles they face in forming and maintaining high-quality friendships with sociable peers. Method: We observed the interactions of 38 socially withdrawn early

Schneider, Barry H.

2009-01-01

44

Early SDO/HMI Magnetic Field Observations (Invited)  

NASA Astrophysics Data System (ADS)

Solar magnetic features no longer have any expectation of privacy and understanding the Sun’s magnetic field is the key to space weather prediction. The Helioseismic and Magnetic Imager on the Solar Dynamics Observatory measures polarized line profiles that measure both line-of-sight and vector magnetic fields in the photosphere. The longitudinal field is measured every 45 seconds with filtergrams from the same camera used to determine the velocity. The Stokes parameters are calculated from a longer sequence taken with a second 4096 x 4096 CCD. Inversion and disambiguation provide an estimate of the vector magnetic field components and uncertainties at least every 12 minutes in active regions. Full disk synoptic observations began in April and magnetograms are available shortly after they are observed from jsoc.stanford.edu along with a plethora of other useful magnetic field products. The low-noise line-of-sight measurements compare favorably with MDI and GONG. The vector field is being compared with other observations and appears quite stable, even in small strong-field concentrations outside of active regions. Scattered light is low and the sensitivity is very good. HMI observes the entire disk all of the time, so any feature of interest can be tracked during its entire disk passage without interruption. Knowing the detailed time development will lead to better understanding of energy storage and release in the atmosphere above and what leads to the spectacular events detected by AIA, EVE, and other instruments.

Hoeksema, J. T.; Hmi Magnetic Field Team

2010-12-01

45

Longitudinal analyses of early lesions by fluorescence: an observational study.  

PubMed

Previous caries experience correlates to future caries risk; thus, early identification of lesions has importance for risk assessment and management. In this study, we aimed to determine if Quantitative Light-induced Fluorescence (QLF) parameters--area (A [mm(2)]), fluorescence loss (F [%]), and Q [% × mm(2)]--obtained by image analyses can predict lesion progression. We secured consent from 565 children (from 5-13 years old) and their parents/guardians and examined them at baseline and regular intervals over 48 months according to the International Caries Detection Assessment System (ICDAS), yearly radiographs, and QLF. QLF images from surfaces with ICDAS 0/1/2/3/4 at baseline that progressed (N = 2,191) to cavitation (ICDAS 5/6) or fillings and surfaces that did not progress to cavitation/fillings (N = 4,141) were analyzed independently for A, F, and Q. Linear mixed-effects models were used to compare means and slopes (changes over time) between surfaces that progressed and those that did not. QLF A, F, and Q increased at a faster rate for surfaces that progressed than for surfaces that did not progress (p = .0001), regardless of type of surface or baseline ICDAS score. AUC for ICDAS ranged from 0.65 to 0.80, but adding QLF information improved AUC (0.82-0.87, p < .0005). We concluded that faster changes in QLF variables can indicate lesion progression toward cavitation and be more clinically relevant than actual QLF values. PMID:23690351

Ferreira Zandoná, A; Ando, M; Gomez, G F; Garcia-Corretjer, M; Eckert, G J; Santiago, E; Katz, B P; Zero, D T

2013-07-01

46

EARLY ULTRAVIOLET OBSERVATIONS OF A TYPE IIn SUPERNOVA (2007pk)  

SciTech Connect

We present some of the earliest UV observations of a Type IIn supernova (SN)-SN 2007pk, where UV and optical observations using Swift's Ultra-Violet/Optical Telescope began 3 days after discovery or {approx}5 days after shock breakout. The SN observations commence at approximately maximum light in the UV and u-band filters, suggesting that the UV light curve peaks begin very rapidly after the initial explosion, and subsequently exhibit a linear decay of 0.20, 0.21, 0.16 mag day{sup -1} in the UVOT uvw2, uvm2, uvw1 ({lambda}{sub c} = 1928, 2246, 2600 Angstrom-Sign ) filters. Meanwhile the b- and v-band light curves begin approximately seven days before v-band peak and exhibit a shallow rise followed by a subsequent decay. A series of optical/near-IR spectra taken with the Hobby-Eberly Telescope at days 3-26 after discovery show spectra similar to that of the peculiar Type IIn 1998S. The emission from 2007pk falls below detection {approx}20 days after discovery in the UV and 50 days in the optical, showing no sign of the long duration emission seen in other Type IIn SNe. We examine the physical and spectral characteristics of 2007pk and compare its UV light curve and decay rate with other Type II SNe.

Pritchard, T. A.; Roming, P. W. A. [Department of Astronomy and Astrophysics, Penn State University, 525 Davey Lab, University Park, PA 16802 (United States); Brown, P. J. [Department of Physics and Astronomy, University of Utah, 115 South 1400 East 201, Salt Lake City, UT (United States); Kuin, N. P. M.; Oates, S. R. [Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT (United Kingdom); Bayless, Amanda J. [Southwest Research Institute, Department of Space Science, 6220 Culebra Rd, San Antonio, TX 78238 (United States); Holland, S. T. [Center for Research and Exploration in Space Science and Technology, NASA/GSFC, Greenbelt, MD 20771 (United States); Immler, S. [Astrophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Milne, P., E-mail: proming@swri.edu [Steward Observatory, 933 North Cherry Avenue, RM N204, Tucson, AZ 85721 (United States)

2012-05-10

47

An EAS event observed in the early stage of development  

NASA Astrophysics Data System (ADS)

Since 1969 the experiments of Brazil-Japan Collaboration showed the occurrence of a series of events, showing a region with a high concentration of electromagnetic particles, surrounded by isolated and/or groups of showers. These events were named "halo events" or "super-families". Currently, we have more than a dozen of such events. The first of them, due to its aspect, was named "Andromeda". We present here the main characteristics of a similar halo event, named C21S087I075. It has a halo region with many high energy showers in its border. Other small energy showers spread over the central and surrounding blocks (S088, S100, S101, I074). These isolated showers, classified as of hadronic or electromagnetic origin, present a fractional energy distribution compatible with that of a Centauro candidate event (C16S087I037), reported at this symposium [S.L.C. Barroso, P.C. Beggio, J.A. Chinellato, A.O. Carvalho, A. Mariano, R. Oliveira, E.H. Shibuya, in this issue of XIV ISVHECRI]. Moreover, the lateral distribution in the halo region is similar to that observed in other 3 halo events.

Barroso, S. L. C.; Beggio, P. C.; de Carvalho, A. O.; Chinellato, J. A.; Mariano, A.; de Oliveira, R.; Shibuya, E. H.; Brazil-Japan Collaboration of Chacaltaya Emulsion Chamber Experiment

2008-01-01

48

Structure development under shear flow during spinodal decomposition of a polymer blend observed by simultaneous measurement of small angle light scattering and rheological functions  

NASA Astrophysics Data System (ADS)

The structure development of the late stage of the spinodal decomposition of a binary polymer blend under shear flow has been studied by simultaneous measurement of rheological functions and the 2-dimensional light scattering pattern obtained by small angle light scattering (SALS). During the structure development at constant shear rate the viscosity passes through maxima which are related to the onset of the structure deformation. In a creep recovery experiment an unusual reversal of the recovery is observed which is related to the relaxation of the anisotropic non-equilibrium morphology.

Gronski, Wolfram; Läuger, Jörg; Laubner, Christian

1996-09-01

49

A Validation of the Early Childhood Classroom Observation Measure in Finnish and Estonian Kindergartens  

ERIC Educational Resources Information Center

Research Findings: The aim of the study was to examine the applicability and psychometric properties of the Early Childhood Classroom Observation Measure (ECCOM; D. J. Stipek & P. Byler, 2005) outside the United States. The ECCOM was used to observe 83 kindergarten teachers (49 in Finland and 34 in Estonia) in classroom situations. Self-ratings…

Lerkkanen, Marja-Kristiina; Kikas, Eve; Pakarinen, Eija; Trossmann, Kaili; Poikkeus, Anna-Maija; Rasku-Puttonen, Helena; Siekkinen, Martti; Nurmi, Jari-Erik

2012-01-01

50

Spinodal Decomposition of Ni-Nb-Y metallic Glasses  

SciTech Connect

Phase-separated Ni-Nb-Y metallic glasses were prepared by rapid quenching from the melt. The early stages of decomposition were characterized in Ni-Nb-Y alloys with Ni contents of more than 60 at.%. Strongly correlated chemical fluctuations with a nanometer length scale were found to exist in the as-quenched state. The observed fluctuation lengths range from 5 to 12 nm, depending on the actual composition of the glass. The 'frozen-in' early stages of decomposition occur in the deeply undercooled melt due to the reduction in the critical temperature of liquid-liquid phase separation with Ni content. Annealing of the phase-separated Ni{sub 70}Nb{sub 15}Y{sub 15} glass below the crystallization temperature leads to an increase in the amplitude of the fluctuations. However, the wavelength was unchanged, which provides evidence for the spinodal character of the decomposition.

Mattern, Norbert [IFW Dresden; G, Goerigk [Forschungszentrum Julich, Julich, Germany; Vainio, U [HASYLAB at DESY, Hamburg, Germany; Miller, Michael K [ORNL; Gemming, T [IFW Dresden; Eckert, J [IFW Dresden

2009-01-01

51

Protein Hydrophobic Collapse and Early Folding Steps Observed in a Microfluidic Mixer  

PubMed Central

We demonstrate that the sub-millisecond protein folding process referred to as “collapse” actually consists of at least two separate processes. We observe the UV fluorescence spectrum from naturally occurring tryptophans in three well-studied proteins, cytochrome c, apomyoglobin, and lysozyme, as a function of time in a microfluidic mixer with a dead time of ?20 ?s. Single value decomposition of the time-dependent spectra reveal two separate processes: 1), a spectral shift which occurs within the mixing time; and 2), a fluorescence decay occurring between ?100 and 300 ?s. We attribute the first process to hydrophobic collapse and the second process to the formation of the first native tertiary contacts.

Lapidus, Lisa J.; Yao, Shuhuai; McGarrity, Kimberly S.; Hertzog, David E.; Tubman, Emily; Bakajin, Olgica

2007-01-01

52

Validity, Reliability, and Utility of the Observation Survey of Early Literacy Achievement  

ERIC Educational Resources Information Center

This study evaluated the validity, reliability, and utility of five of the six subtests of Clay's (2002) Observation Survey of Early Literacy Achievement (OS), including Letter Identification, Word Reading, Writing Vocabulary, Hearing and Recording Sounds in Words, and Text Reading. In addition to a review of studies providing assessment of the…

Denton, Carolyn A.; Ciancio, Dennis J.; Fletcher, Jack M.

2006-01-01

53

Factors Associated with South Korean Early Childhood Educators' Observed Behavior Support Strategies  

ERIC Educational Resources Information Center

This study was an exploratory study of 34 South Korean early childhood educators' strategies for addressing behavior problems in natural settings. Factors related to teachers' strategy implementation were also explored. Four specific teacher behaviors were observed: precorrection, behavioral-specific praise, redirection, and reprimand/punishment.…

Kim, Yeon Ha; Stormont, Melissa

2012-01-01

54

Sector Decomposition  

Microsoft Academic Search

Sector decomposition is a constructive method to isolate divergences from parameter integrals occurring in perturbative quantum field theory. We explain the general algorithm in detail and review its application to multiloop Feynman parameter integrals as well as infrared divergent phase-space integrals over real radiation matrix elements.

Gudrun Heinrich

2008-01-01

55

Decomposing observations of high-frequency radar-derived surface currents by their forcing mechanisms: Decomposition techniques and spatial structures of decomposed surface currents  

NASA Astrophysics Data System (ADS)

Surface current observations from a high-frequency radar network deployed in southern San Diego are decomposed according to their driving forces: pure tides and their neighboring off-band energy, local winds, and low frequency. Several superposed ocean responses are present as a result of the complicated bottom topography and relatively weak winds off southern San Diego, as opposed to coastal regions where circulation can be explained by a dominant forcing mechanism. This necessitates an application of a statistical decomposition approach. Surface currents coherent with pure tides are calculated using harmonic analysis. Locally wind-driven surface currents are estimated by regression of observed winds on observed surface currents. The dewinded and detided surface currents are filtered by weighted least-squares fitting assuming white noise and three colored signal bands: low-frequency band (less than 0.4 cycles per day) and near-tidal peaks at the diurnal (K1) and semidiurnal (M2) frequencies. The spatial and temporal variability of each part of the decomposed surface currents is investigated in terms of ocean response to the driving forces. In addition, the spatial correlations of individual components exhibit Gaussian and exponential shapes with varying decorrelation length scales.

Kim, Sung Yong; Cornuelle, Bruce D.; Terrill, Eric J.

2010-12-01

56

Fitting model fields to observations by using singular value decomposition: An ensemble-based 4DVar approach  

NASA Astrophysics Data System (ADS)

An ensemble-based four-dimensional variational data assimilation (4DVar) method is proposed to fit the model field to 4-D observations in an increment form in the analysis step of data assimilation. The fitting is similar to that in the 4DVar but the analysis increment is expressed by a linear combination of the leading singular vectors extracted from an ensemble of 4-D perturbation solutions, so the fitting is computationally very efficient and does not require any adjoint integration. In the cost function used for the fitting, the background error covariance matrix is constructed implicitly by the perturbation solutions (through their representative singular vectors) similarly to that in the ensemble Kalman filter, but the perturbation solutions are not updated by the analysis into the next assimilation cycle, so the analysis is simpler and more efficient than that in the ensemble Kalman filter. The potential merits of the method are demonstrated by three sets of observing system simulation experiments performed with a shallow-water equation model. The method is shown to be robust even when the model is imperfect and the observations are incomplete.

Qiu, Chongjian; Shao, Aimei; Xu, Qin; Wei, Li

2007-06-01

57

Observing the Cosmic Microwave Background Radiation: A Unique Window on the Early Universe  

NASA Technical Reports Server (NTRS)

The cosmic microwave background radiation is the remnant heat from the Big Bang. It provides us with a unique probe of conditions in the early universe, long before any organized structures had yet formed. The anisotropy in the radiation's brightness yields important clues about primordial structure and additionally provides a wealth of information about the physics,of the early universe. Within the framework of inflationary dark matter models observations of the anisotropy on sub-degree angular scales will reveal the signatures of acoustic oscillations of the photon-baryon fluid at a redshift of approx. 1100. The validity of inflationary models will be tested and, if agreement is found, accurate values for most of the key cosmological parameters will result. If disagreement is found, we will need to rethink our basic ideas about the physics of the early universe. I will present an overview of the physical processes at work in forming the anisotropy and discuss what we have already learned from current observations. I will conclude with a brief overview of the recently launched Microwave Anisotropy Probe (MAP) mission which will observe the anisotropy over the full sky with 0.21 degree angular resolution. At the time of this meeting, MAP will have just arrived at the L2 Lagrange point, marking the start of its observing campaign. The MAP hardware is being produced by Goddard in partnership with Princeton University.

Hinshaw, Gary; Fisher, Richard R. (Technical Monitor)

2001-01-01

58

Observed Arctic Ocean clouds, sea ice, and radiative fluxes during the early 21st century (Invited)  

NASA Astrophysics Data System (ADS)

Arctic Ocean satellite observations (A-train, CERES-EBAF) are combined to create a cloud and radiation climatology for the early 21st century. The climatology exposes large geographic, seasonal, and interannual variability in cloud forcing but on average, Arctic Ocean clouds warm the surface by 10 W/m2 and reduce incoming top-of-atmosphere (TOA) radiation by 12 W/m2. During the early 21st century, summer Arctic TOA albedo decreases can be explained by sea ice loss but are unrelated to summer cloud trends that are statistically insignificant. In contrast, both sea ice variability and cloud variability contribute to interannual variability in summer shortwave radiative fluxes. In summary, the observations show that while cloud variability influences absorbed shortwave radiation variability, there is no summer cloud trend affecting summer absorbed shortwave radiation (Kay and L'Ecuyer 2013 JGR). Implications of these findings for Arctic shortwave climate feedbacks and model evaluation are discussed.

Kay, J. E.; L'Ecuyer, T. S.; Gettelman, A.

2013-12-01

59

Observation M Methodology iin P Preschool P Programme E Evaluation: The E Early S Start E Experience  

Microsoft Academic Search

The ECERS-R, a classroom observation otherwise known as the Early Childhood Environmental Rating Scale, was used as part of the evaluation of Early Start, a preschool programme in disadvantaged areas in Irish cities. An evaluation report to the Department of Education and Science (Lewis and Archer, 2003) is concerned with what was learned about Early Start from the use of

Mary L Lewis; P Peter; A Archer

60

Observational constraints on Arctic Ocean clouds and radiative fluxes during the early 21st century  

NASA Astrophysics Data System (ADS)

Arctic Ocean observations are combined to create a cloud and radiation climatology for the early 21st century (March 2000 to February 2011). Data sources include: active (CloudSat, CALIPSO) and passive (MODIS) satellite cloud observations, observed top-of-atmosphere (TOA) radiative fluxes (CERES-EBAF), observationally constrained radiative flux calculations (2B-FLXHR-LIDAR), and observationally constrained cloud forcing calculations (CERES-EBAF, 2B-FLXHR-LIDAR). Uncertainty in flux calculations is dominated by cloud uncertainty, not surface albedo uncertainty. The climatology exposes large geographic, seasonal, and interannual variability cloud forcing, but on average, Arctic Ocean clouds warm the surface (+10 W m-2, in 2B-FLXHR-LIDAR) and cool the TOA (-12 W m-2, in CERES-EBAF and 2B-FLXHR-LIDAR). Shortwave TOA cloud cooling and longwave TOA cloud warming are stronger in 2B-FLXHR-LIDAR than in CERES-EBAF, but these two differences compensate each other, yielding similar net TOA values. During the early 21st century, summer TOA albedo decreases are consistent with sea ice loss but are unrelated to summer cloud trends that are statistically insignificant. In contrast, both sea ice variability and cloud variability contribute to interannual variability in summer shortwave radiative fluxes. Summer 2007 had the largest persistent cloud, radiation, and sea ice anomalies in the climatology. During that summer, positive net shortwave radiation anomalies exceeded 20 W m-2 over much of the Arctic Ocean. This enhanced shortwave absorption resulted primarily from cloud reductions during early summer and sea ice loss during late summer. In summary, the observations show that while cloud variability influences absorbed shortwave radiation variability, there is no summer cloud trend affecting summer absorbed shortwave radiation.

Kay, Jennifer E.; L'Ecuyer, Tristan

2013-07-01

61

Towards Characterizing Early-stage SEP Fluxes with High-Cadence EUV Coronal Shock Observations  

NASA Astrophysics Data System (ADS)

Recent advances in space-based solar observing have enabled unprecedented access to high-cadence, high-resolution observations of the coronal dynamics. This is extremely important, since transient phenomena in the corona usually cover multiple scales - from the current spatial resolution limit in the case of reconnection, to several solar radii in the case of coronal waves and mass ejections. The latter are also thought to drive shocks in the corona, which in turn have been shown capable of accelerating protons, electrons, and other species up to GeV energies in a matter of tens of minutes. These solar energetic particles (SEPs) are a prime source of space weather. Historically, it has been notoriously difficult to extract information about energetic particle spectra in the corona, due to the lack of in situ measurements. It is possible, however, to use remote observations in order to deduce coronal shock dynamics and related particle spectra, with some reasonable assumptions. We present an effort towards building a framework for estimating coronal SEP spectra in the early stages of real CME events, based on a combination of fast-cadence extreme ultraviolet imaging (from the SDO/AIA instrument), potential coronal magnetic field models, and differential emission measure models. The ultimate goal for this framework is to give predictions for early-stage SEP spectra for various source populations and coronal turbulence levels. It is designed in a modular fashion, and may be adapted for near real time use. This system can be applied for early warning and predicting the severity of the impulsive early stages of SEP events.

Kozarev, Kamen A.; Raymond, John C.; Hammer, Michael

2014-06-01

62

The Uffo Slewing Mirror Telescope for Early Optical Observation from Gamma Ray Bursts  

NASA Astrophysics Data System (ADS)

While some space born observatories, such as SWIFT and FERMI, have been operating, early observation of optical after grow of GRBs is still remained as an unexplored region. The Ultra-Fast Flash Observatory (UFFO) project is a space observatory for optical follow-ups of GRBs, aiming to explore the first 60 seconds of GRBs optical emission. Using fast moving mirrors to redirect our optical path rather than slewing the entire spacecraft, UFFO is utilized to catch early optical emissions from GRB within 1 sec. We have developed the UFFO Pathfinder Telescope which is going to be on board of the Lomonosov satellite and launched in middle of 2012. We will discuss about scientific potentials of the UFFO project and present the payload development status, especially for Slewing Mirror Telescope which is the key instrument of the UFFO-pathfinder mission.

Nam, Jiwoo; Ahmad, S.; Ahn, K.; Barrillon, P.; Brandt, S.; Budtz-Jørgensen, C.; Castro-Tirado, A. J.; Chang, S.-H.; Chen, C.-R.; Chen, P.; Choi, Y. J.; Connell, P.; Dagoret-Campagne, S.; Eyles, C.; Grossan, B.; Huang, M.-H. A.; Huang, J.-J.; Jeong, S.; Jung, A.; Kim, J. E.; Kim, S. H.; Kim, Y. W.; Lee, J.; Lim, H.; Lin, C.-Y.; Linder, E. V.; Liu, T.-C.; Lund, N.; Min, K. W.; Na, G. W.; Panayuk, M. I.; Park, I. H.; Ripa, J.; Reglero, V.; Rodrigo, J. M.; Smoot, G. F.; Svertilov, S.; Vedenkin, N.; Wang, M.-Z.; Yashin, I.; Zhao, M. H.

2013-01-01

63

The Uffo Slewing Mirror Telescope for Early Optical Observation from Gamma Ray Bursts  

NASA Astrophysics Data System (ADS)

While some space born observatories, such as SWIFT and FERMI, have been operating, early observation of optical after grow of GRBs is still remained as an unexplored region. The Ultra-Fast Flash Observatory (UFFO) project is a space observatory for optical follow-ups of GRBs, aiming to explore the first 60 seconds of GRBs optical emission. Using fast moving mirrors to redirect our optical path rather than slewing the entire spacecraft, UFFO is utilized to catch early optical emissions from GRB within 1 sec. We have developed the UFFO Pathfinder Telescope which is going to be on board of the Lomonosov satellite and launched in middle of 2012. We will discuss about scientific potentials of the UFFO project and present the payload development status, especially for Slewing Mirror Telescope which is the key instrument of the UFFO-pathfinder mission.

Nam, Jiwoo; Ahmad, S.; Ahn, K.; Barrillon, P.; Brandt, S.; Budtz-Jørgensen, C.; Castrotirado, A. J.; Chang, S.-H.; Chen, C.-R.; Chen, P.; Choi, Y. J.; Connell, P.; Dagoret-Campagne, S.; Eyles, C.; Grossan, B.; Huang, M.-H. A.; Huang, J.-J.; Jeong, S.; Jung, A.; Kim, J. E.; Kim, S. H.; Kim, Y. W.; Lee, J.; Lim, H.; Lin, C.-Y.; Linder, E. V.; Liu, T.-C.; Lund, N.; Min, K. W.; Na, G. W.; Panayuk, M. I.; Park, I. H.; Ripa, J.; Reglero, V.; Rodrigo, J. M.; Smoot, G. F.; Svertilov, S.; Vedenkin, N.; Wang, M.-Z.; Yashin, I.; Zhao, M. H.

2013-12-01

64

EPR (Electron Paramagnetic Resonance) Observation of Nitroxide Free Radicals during Thermal Decomposition of 2,4,6-Trinitrotoluene and Related Compounds.  

National Technical Information Service (NTIS)

Many of the explosives and propellants used for commercial and defense applications incorporate 2,4,6-trinitrotoluene (TNT) as a major component of the formulation. The thermal decomposition of TNT has important implications for the stability and reliabil...

T. M. McKinney L. F. Warren I. B. Goldberg J. T. Swanson

1986-01-01

65

Constraining the temperature history of the past millennium using early instrumental observations  

NASA Astrophysics Data System (ADS)

The current assessment that twentieth-century global temperature change is unusual in the context of the last thousand years relies on estimates of temperature changes from natural proxies (tree-rings, ice-cores etc.) and climate model simulations. Confidence in such estimates is limited by difficulties in calibrating the proxies and systematic differences between proxy reconstructions and model simulations - notable differences include large differences in multi-decadal variability between proxy reconstructions, and big uncertainties in the effect of volcanic eruptions. Because the difference between the estimates extends into the relatively recent period of the early nineteenth century it is possible to compare them with a reliable instrumental estimate of the temperature change over that period, provided that enough early thermometer observations, covering a wide enough expanse of the world, can be collected. By constraining key aspects of the reconstructions and simulations, instrumental observations, inevitably from a limited period, can reduce reconstruction uncertainty throughout the millennium. A considerable quantity of early instrumental observations are preserved in the world's archives. One organisation which systematically made observations and collected the results was the English East-India Company (EEIC), and 900 log-books of EEIC ships containing daily instrumental measurements of temperature and pressure have been preserved in the British Library. Similar records from voyages of exploration and scientific investigation are preserved in published literature and the records in National Archives. Some of these records have been extracted and digitised, providing hundreds of thousands of new weather records offering an unprecedentedly detailed view of the weather and climate of the late eighteenth and early nineteenth centuries. The new thermometer observations demonstrate that the large-scale temperature response to the Tambora eruption and the 1809 eruption was modest (perhaps 0.5C). This provides a powerful out-of-sample validation for the proxy reconstructions --- supporting their use for longer-term climate reconstructions. However, some of the climate model simulations in the CMIP5 ensemble show much larger volcanic effects than this --- such simulations are unlikely to be accurate in this respect.

Brohan, P.

2012-12-01

66

Two Early Sunspots Observers: Teodoro de Almeida and José Antonio Alzate  

NASA Astrophysics Data System (ADS)

We present the sunspot ideas and observations of the 18th century Portuguese scholar Teodoro de Almeida (1722 1804) and Mexican scientist José Antonio Alzate (1737 1799). We describe the implications of dating a single sunspot observation performed by Almeida in the early 1760s, during the maximum of cycle number 1. A possible solar cycle peak in 1760 (instead of 1761) is investigated. We present several observations of sunspots obtained by Alzate during 1769 (partially associated with the Venus and Mercury transits) and also on 20 July 1786. We estimate 100±34 as the Group Sunspot Number for this date. These records were unknown and, therefore, not included in the database compiled by Hoyt and Schatten (1998).

Vaquero, J. M.; Trigo, R. M.; Gallego, M. C.; Moreno-Corral, M. A.

2007-01-01

67

Constraining the temperature history of the past millennium using early instrumental observations  

NASA Astrophysics Data System (ADS)

The current assessment that twentieth-century global temperature change is unusual in the context of the last thousand years relies on estimates of temperature changes from natural proxies (tree-rings, ice-cores, etc.) and climate model simulations. Confidence in such estimates is limited by difficulties in calibrating the proxies and systematic differences between proxy reconstructions and model simulations. As the difference between the estimates extends into the relatively recent period of the early nineteenth century it is possible to compare them with a reliable instrumental estimate of the temperature change over that period, provided that enough early thermometer observations, covering a wide enough expanse of the world, can be collected. One organisation which systematically made observations and collected the results was the English East India Company (EEIC), and their archives have been preserved in the British Library. Inspection of those archives revealed 900 log-books of EEIC ships containing daily instrumental measurements of temperature and pressure, and subjective estimates of wind speed and direction, from voyages across the Atlantic and Indian Oceans between 1789 and 1834. Those records have been extracted and digitised, providing 273 000 new weather records offering an unprecedentedly detailed view of the weather and climate of the late eighteenth and early nineteenth centuries. The new thermometer observations demonstrate that the large-scale temperature response to the Tambora eruption and the 1809 eruption was modest (perhaps 0.5 °C). This provides an out-of-sample validation for the proxy reconstructions - supporting their use for longer-term climate reconstructions. However, some of the climate model simulations in the CMIP5 ensemble show much larger volcanic effects than this - such simulations are unlikely to be accurate in this respect.

Brohan, P.; Allan, R.; Freeman, E.; Wheeler, D.; Wilkinson, C.; Williamson, F.

2012-10-01

68

Constraining the temperature history of the past millennium using early instrumental observations  

NASA Astrophysics Data System (ADS)

The current assessment that twentieth-century global temperature change is unusual in the context of the last thousand years relies on estimates of temperature changes from natural proxies (tree-rings, ice-cores etc.) and climate model simulations. Confidence in such estimates is limited by difficulties in calibrating the proxies and systematic differences between proxy reconstructions and model simulations. As the difference between the estimates extends into the relatively recent period of the early nineteenth century it is possible to compare them with a reliable instrumental estimate of the temperature change over that period, provided that enough early thermometer observations, covering a wide enough expanse of the world, can be collected. One organisation which systematically made observations and collected the results was the English East-India Company (EEIC), and their archives have been preserved in the British Library. Inspection of those archives revealed 900 log-books of EEIC ships containing daily instrumental measurements of temperature and pressure, and subjective estimates of wind speed and direction, from voyages across the Atlantic and Indian Oceans between 1789 and 1834. Those records have been extracted and digitised, providing 273 000 new weather records offering an unprecedentedly detailed view of the weather and climate of the late eighteenth and early nineteenth centuries. The new thermometer observations demonstrate that the large-scale temperature response to the Tambora eruption and the 1809 eruption was modest (perhaps 0.5 °C). This provides a powerful out-of-sample validation for the proxy reconstructions - supporting their use for longer-term climate reconstructions. However, some of the climate model simulations in the CMIP5 ensemble show much larger volcanic effects than this - such simulations are unlikely to be accurate in this respect.

Brohan, P.; Allan, R.; Freeman, E.; Wheeler, D.; Wilkinson, C.; Williamson, F.

2012-05-01

69

Radio continuum observations of early- and late-type spiral galaxies  

NASA Technical Reports Server (NTRS)

Two complete subsamples of early and late type spiral galaxies were mapped with the VLA in order to explore their radio and optical properties. The choice of the samples is explained, and the observational procedure and data reduction are described. The detection rate was 97 percent, with a detection limit of the order of 1-2 mJy. Total intensity data at 20 cm are presented for the whole sample, and 6 cm data for 11 galaxies. The results are presented in the form of tables and radio contour maps, and are discussed in comparison with previous work.

Gioia, Isabella M.; Fabbiano, Giuseppina

1987-01-01

70

Rare examples of early VLF events observed in association with ISUAL-detected gigantic jets  

NASA Astrophysics Data System (ADS)

We examine narrowband VLF observations and investigate the association of early VLF perturbations with gigantic jets recorded by the Imager of Sprites and Upper Atmospheric Lightnings (ISUAL) instrument aboard FORMOSAT-2. From its inception in 2004 to April 2013, the ISUAL instrument has recorded 90 gigantic jets using a triggered camera. Stanford VLF receivers located around the world are used to detect perturbations to VLF transmitter signals associated with lightning. While nine gigantic jet events occurred within 100 km of a VLF transmitter-receiver great circle path, only four early VLF events were detected in association with three ISUAL gigantic jets. One of these is a moderate event of 0.4 dB amplitude change, and the others are very small. The recovery time of these events are less than a couple of minutes and so do not constitute the "long recovery" early VLF events that have been postulated to be associated with gigantic jets. We speculate on possible explanations for the lack of other events on monitored paths, including a lack of significant ionization produced in the D region ionosphere by the gigantic jet event, weak transmitter signals recorded by the receivers, or mode effects on transmitter paths.

Marshall, R. A.; Adachi, T.; Hsu, R.-R.; Chen, A. B.

2014-01-01

71

EARLY PHASE OBSERVATIONS OF EXTREMELY LUMINOUS TYPE Ia SUPERNOVA 2009dc  

SciTech Connect

We present early phase observations in optical and near-infrared wavelengths for the extremely luminous Type Ia supernova (SN Ia) 2009dc. The decline rate of the light curve is DELTAm{sub 15}(B) = 0.65 +- 0.03, which is one of the slowest among SNe Ia. The peak V-band absolute magnitude is estimated to be M{sub V} = -19.90 +- 0.15 mag if no host extinction is assumed. It reaches M{sub V} = -20.19 +- 0.19 mag if we assume the host extinction of A{sub V} = 0.29 mag. SN 2009dc belongs to the most luminous class of SNe Ia, like SNe 2003fg and 2006gz. Our JHK{sub s} -band photometry shows that this SN is also one of the most luminous SNe Ia in near-infrared wavelengths. We estimate the ejected {sup 56}Ni mass of 1.2 +- 0.3 M{sub sun} for the no host extinction case (and of 1.6 +- 0.4 M{sub sun} for the host extinction of A{sub V} = 0.29 mag). The C II lambda6580 absorption line remains visible until a week after the maximum brightness, in contrast to its early disappearance in SN 2006gz. The line velocity of Si II lambda6355 is about 8000 km s{sup -1} around the maximum, being considerably slower than that of SN 2006gz. The velocity of the C II line is similar to or slightly less than that of the Si II line around the maximum. The presence of the carbon line suggests that the thick unburned C+O layer remains after the explosion. Spectropolarimetric observations by Tanaka et al. indicate that the explosion is nearly spherical. These observational facts suggest that SN 2009dc is a super-Chandrasekhar mass SN Ia.

Yamanaka, M.; Arai, A.; Chiyonobu, S.; Fukazawa, Y.; Ikejiri, Y.; Itoh, R.; Komatsu, T.; Miyamoto, H. [Department of Physical Science, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima 739-8526 (Japan); Kawabata, K. S. [Hiroshima Astrophysical Science Center, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Kinugasa, K.; Hashimoto, O.; Honda, S. [Gunma Astronomical Observatory, Takayama, Gunma 377-0702 (Japan); Tanaka, M. [Department of Astronomy, School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan); Imada, A.; Kuroda, D. [Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Kamogata, Asakuchi-shi, Okayama 719-0232 (Japan); Maeda, K.; Nomoto, K. [Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa (Japan); Kamata, Y. [National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo 181-8588 (Japan); Kawai, N. [Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551 (Japan); Konishi, K., E-mail: myamanaka@hiroshima-u.ac.j [Institute for Cosmic Ray Research, University of Tokyo, 5-1-5, Kashiwanoha, Kashiwa, Chiba, 277-8582 (Japan)

2009-12-20

72

HST WFC3 Early Release Science: Emission-line Galaxies from IR Grism Observations  

NASA Astrophysics Data System (ADS)

The Early Release Science II program for HST WFC3 includes one pointing observed with the G102 (0.8-1.1 microns; R 210) and G141 (1.1-1.6 microns; R 130) infrared grisms at a depth of 2 orbits/grism. From this data we detect 48 actively star-forming emission-line galaxies and measure the galaxies' redshifts, line fluxes, star-formation rates, and masses. In particular, the prominent emission lines Ha, [OII], and [OIII] fall into the two infrared grism bandpasses over a redshift range z=0.2-3.6, and the majority of galaxies have at least two lines in the observable wavelength range resulting in secure line identification and redshift determination. We detect galaxies with line fluxes to 3 x 10-17 erg/s/cm2 as well as several sources with very high EW lines. The higher spectral resolution and sensitivity of the WFC3 grisms over previous instrumentation also allows detection of other emission lines in some galaxies. The average magnitude of the emission-line galaxy sample is mAB(F098M)=23.6 mag with more than 20% of the sample fainter than mAB(F098M)=25 mag, demonstrating the remarkable efficiency and capability of the WFC3 NIR grisms for measuring galaxy properties to faint magnitudes and intermediate redshifts. Our results point to the promising potential for future science with WFC3 grism spectroscopy, as well as upcoming missions such as JWST and WFIRST. This paper is based on Early Release Science observations made by the WFC3 Scientific Oversight Committee. We are grateful to the Director of the Space Telescope Science Institute for awarding Director's Discretionary time for this program. This research was supported in part by an appointment to the NASA Postdoctoral Program at Goddard Space Flight Center, administered by Oak Ridge Associated Universities through a contract with NASA (ANS).

Straughn, Amber; Kuntschner, H.; Kuemmel, M.; Walsh, J.; Cohen, S.; Gardner, J. P.; Windhorst, R. A.; O'Connell, R. W.; Pirzkal, N.; Meurer, G.; McCarthy, P. J.; Hathi, N. P.; Malhotra, S.; Rhoads, J.; SOC, WFC3

2011-01-01

73

ASCA observation of three bright early-type galaxies: NGC 4472, NGC 4406, and NGC 4636  

NASA Technical Reports Server (NTRS)

We report Advanced Satellite for Cosmology and Astrophysics (ASCA) 0.3-10 keV and X-ray observations of three early type galaxies, NGC 4472, NGC 4406, and NGC 4636. The extended mission in these galaxies is well described by thin thermal eimssion from hot gas. The gas temperature is 0.92 +/- 0.02 keV for NGC 4472, 0.79 +/- 0.01 keV for NGC 4406, and 0.73 +/- 0.02 keV for NGC 4636. The metal abundance for NGC 4472, NGC 4406, and NGC 4636 are, under the assumption of solar ratios, 0.63 +/- 0.15, 0.45 +/- 0.10, and 0.38 +/- 0.07, respectively. Detailed analysis has allowed determination of the abundances of oxygen, silicon, sulfur, and iron. The observed abundances are consistent with the solar ratios. For NGC 4472 and NGC 4406 we also determined the mean temperature of the gas producing the Si lines from the ratio of the Si H to He-like lines and find it to be consistent with the continuum temperature. The X-ray temperature is in good agreement with the observed optical velocity dispersion, stellar density profile, and gas density profile. Our data indicates that the supernova rate should be less than one fifth of the nominal rate in early type galaxies. We derive the mass of these systems within fixed angular scales and find that M/L greater than 40, confirming that elliptical galaxies are dark matter dominated at large radii.

Awaki, Hisamitsu; Mushotzky, Richard; Tsuru, Takeshi; Fabian, Andrew C.; Fukazawa, Yasushi; Loewenstein, Michael; Makishima, Kazuo; Matsumoto, Hironori; Matsushita, Kyoko; Mihara, Tatehiro

1994-01-01

74

Ultra-Fast Flash Observatory for observation of early photons from gamma ray bursts  

NASA Astrophysics Data System (ADS)

We describe the space project of Ultra-Fast Flash Observatory (UFFO) which will observe early optical photons from gamma-ray bursts (GRBs) with a sub-second optical response, for the first time. The UFFO will probe the early optical rise of GRBs, opening a completely new frontier in GRB and transient studies, using a fast response Slewing Mirror Telescope (SMT) that redirects optical path to telescope instead of slewing of telescopes or spacecraft. In our small UFFO-Pathfinder experiment, scheduled to launch aboard the Lomonosov satellite in 2012, we use a motorized mirror in our Slewing Mirror Telescope instrument to achieve less than one second optical response after X-ray trigger. We describe the science and the mission of the UFFO project, including a next version called UFFO-100. With our program of ultra-fast optical response GRB observatories, we aim to gain a deeper understanding of GRB mechanisms, and potentially open up the z<10 universe to study via GRB as point source emission probes.

Park, I. H.; Ahmad, S.; Barrillon, P.; Brandt, S.; Budtz-Jørgensen, C.; Castro-Tirado, A. J.; Chen, P.; Choi, Y. J.; Connell, P.; Dagoret-Campagne, S.; Eyles, C.; Grossan, B.; Huang, M.-H. A.; Jeong, S.; Jung, A.; Kim, J. E.; Kim, M. B.; Kim, S.-W.; Kim, Y. W.; Krasnov, A. S.; Lee, J.; Lim, H.; Linder, E. V.; Liu, T.-C.; Lund, N.; Min, K. W.; Na, G. W.; Nam, J. W.; Panasyuk, M. I.; Ripa, J.; Reglero, V.; Rodrigo, J. M.; Smoot, G. F.; Suh, J. E.; Svertilov, S.; Vedenkin, N.; Wang, M.-Z.; Yashin, I.

2012-09-01

75

Early observational research and registries during the 2009-2010 influenza A pandemic.  

PubMed

As a critical care community, we have an obligation to provide not only clinical care but also the research that guides initial and subsequent clinical responses during a pandemic. There are many challenges to conducting such research. The first is speed of response. However, given the near inevitability of certain events, for example, viral respiratory illness such as the 2009 pandemic, geographically circumscribed natural disasters, or acts of terror, many study and trial designs should be preplanned and modified quickly when specific events occur. Template case report forms should be available for modification and web entry; centralized research ethics boards and funders should have the opportunity to preview and advise on such research beforehand; and national and international research groups should be prepared to work together on common studies and trials for common challenges. We describe the early international critical care research response to the influenza A 2009 (H1N1) pandemic, including specifics of observational study case report form, registry, and clinical trial design, cooperation of international critical care research organizations, and the early results of these collaborations. PMID:20101176

Fowler, Robert A; Webb, Steven A R; Rowan, Kathy M; Sprung, Charles L; Thompson, B Taylor; Randolph, Adrienne G; Jouvet, Philippe; Lapinsky, Stephen; Rubinson, Lewis; Rello, Jordi; Cobb, J Perren; Rice, Todd W; Uyeki, Tim; Marshall, John C

2010-04-01

76

Early observational research and registries during the 2009-2010 influenza A pandemic  

PubMed Central

As a critical care community, we have an obligation to provide not only clinical care but also the research that guides initial and subsequent clinical responses during a pandemic. There are many challenges to conducting such research. The first is speed of response. However, given the near inevitability of certain events, for example, viral respiratory illness such as the 2009 pandemic, geographically circumscribed natural disasters, or acts of terror, many study and trial designs should be preplanned and modified quickly when specific events occur. Template case report forms should be available for modification and web entry; centralized research ethics boards and funders should have the opportunity to preview and advise on such research beforehand; and national and international research groups should be prepared to work together on common studies and trials for common challenges. We describe the early international critical care research response to the influenza A 2009 (H1N1) pandemic, including specifics of observational study case report form, registry, and clinical trial design, cooperation of international critical care research organizations, and the early results of these collaborations.

Fowler, Robert A.; Webb, Steven A. R.; Rowan, Kathy M.; Sprung, Charles L.; Thompson, B. Taylor; Randolph, Adrienne G.; Jouvet, Philippe; Lapinsky, Stephen; Rubinson, Lewis; Rello, Jordi; Cobb, J. Perren; Rice, Todd W.; Uyeki, Tim; Marshall, John C.

2013-01-01

77

Observation of Steric Conformational Effects in Hydrocarbon Adsorption and Decomposition: Cis- and Trans-Butene-2 on Si(100)-(2x1).  

National Technical Information Service (NTIS)

Adsorption, desorption and decomposition of the isomeric hydrocarbons, cis- and trans-butene-2, on Si(100)-(2 X 1) have been studied by means of a kinetic uptake method, temperature programmed desorption (TPD) and Auger electron spectroscopy (AES). Both b...

M. Kiskinova J. T. Yates

1995-01-01

78

Linear decomposition-based methodology for determining the relative importance of wind and non-wind phenomena on observed air quality  

NASA Astrophysics Data System (ADS)

Air pollution in Hong Kong (HK) is becoming more significant. Many people have expressed their concern about changes in air quality. The problems and concerns have been manifest, in recent years, in HK and the Pearl River Delta (PRD) region. Typically, it is believed that increased emissions should be blamed for causing air pollution in this region. However, the authorities explain that increased occurrence in calm/light wind conditions is also important in hindering dispersion of air pollutants. Understanding the real causes can benefit in setting the best control policies. The conflict between the "emission" and "wind pattern" viewpoints can be resolved if we can distinguish the respective contributions of wind changes (wind influence) and emission strengths (non-wind influence) on air quality. However, up to now, there has been no systematic way to determine the relative importance of these two main phenomena on air quality. Most current related research can only show they have an impact on air quality. Little has compared them quantitatively. This research first investigated whether the frequency of calm/light wind conditions is closely related to the concentration of pollutants. The plotted charts show high wind speed with low pollutant concentration and vice versa. Although the frequency distributions of wind speed in 2000 -- 2003 versus 2004 -- 2007 do show that there was a higher frequency of low wind speeds in the latter period, when pollution levels are compared during periods of similar wind speed, they are higher in the latter period than in the former. A linear decomposition-based methodology is proposed to distinguish the relative importance of these two main phenomena on air quality. Based on the hourly wind data (speed and direction) and pollutant concentration, the wind frequency and pollutant emission "roses" (circular frequency diagrams) are established. Hypothetical pollutant concentration can be calculated from these two roses. By comparing the hypothetical pollutant concentration with the actual measurement, the relative importance of these two main phenomena on average pollutant concentration in two periods can be determined respectively quantitatively. Last, the respirable suspended particulates (RSP), ozone (O3), nitrogen dioxide (NO2) and sulphur dioxide (SO2) in 2000 -- 2007 in HK were analyzed and two past air quality related controversial cases were also studied. It is shown that the non-wind influence on observed air quality in HK was more significant than the wind influence in annual-based comparison.

Wong, Kit Man

79

Early Results from the First Year of Observations by the Atacama B-mode Search (ABS)  

NASA Astrophysics Data System (ADS)

The Atacama B-mode Search (ABS) instrument, which began observation in February of 2012, is a crossed-Dragone telescope located at an elevation of 5100 m in the Atacama Desert in Chile. The primary scientific goal of ABS is to measure the B-mode polarization spectrum of the Cosmic Microwave Background (CMB) from multipole moments of about l=50 to l=500, a range that includes the primordial B-mode peak. Unlike most current polarization experiments, ABS features a cryogenic telescope and a warm half-wave plate used to modulate the polarization of the incoming light. The ABS focal plane array consists of 240 pixels designed for observation at 150 GHz by the TRUCE collaboration. Each pixel has its own individual, single-moded feedhorn and contains two transition-edge sensor (TES) bolometers sensitive to orthogonal polarizations. The detectors are read out using time domain multiplexing so that the thermal loading of the readout electronics does not heat the focal plane. I will present early results from the first year of ABS data.

Simon, Sara M.; ABS Collaboration

2013-06-01

80

The light up and evolution of early Massive Black Holes: Athena observations  

NASA Astrophysics Data System (ADS)

The known AGN population at z > 6 is made by luminous optical QSO hosting Supermassive Black Holes (M > 10^9 solar masses), likely to represent the tip of the iceberg of the luminosity and mass function. According to theoretical models for structure formation, Massive Black Holes (MBH -- 10^4-10^7 solar masses) are predicted to be abundant in the early Universe (z > 6). The detection of such a population would provide unique constraints on the MBH formation mechanism and subsequent growth and is within the capabilities of deep and ultradeep ATHENA surveys. I will summarize the state of the art of present deep XMM and Chandra surveys, as far as the search for and spectral characterization of high redshift AGN is concerned. I will also present the observational strategy of future multi-cone ATHENA Wide Field Imager (WFI) surveys and the expected breakthroughs in the determination of the luminosity function and its evolution at high (> 4) and very high (> 6) redshifts. Perspectives for high spectral resolution observations with the XMS calorimeter onboard ATHENA will also be outlined.

Comastri, Andrea

2012-07-01

81

Earth Observing System (EOS) Aqua Launch and Early Mission Attitude Support Experiences  

NASA Technical Reports Server (NTRS)

The Earth Observing System (EOS) Aqua satellite was successfully launched on May 4,2002. Aqua is the second in the series of EOS satellites. EOS is part of NASA s Earth Science Enterprise Program, whose goals are to advance the scientific understanding of the Earth system. Aqua is a three-axis stabilized, Earth-pointing spacecraft in a nearly circular, sun-synchronous orbit at an altitude of 705 km. The Goddard Space Flight Center (GSFC) Flight Dynamics attitude team supported all phases of the launch and early mission. This paper presents the main results and lessons learned during this period, including: real-time attitude mode transition support, sensor calibration, onboard computer attitude validation, response to spacecraft emergencies, postlaunch attitude analyses, and anomaly resolution. In particular, Flight Dynamics support proved to be invaluable for successful Earth acquisition, fine-point mode transition, and recognition and correction of several anomalies, including support for the resolution of problems observed with the MODIS instrument.

Tracewell, D.; Glickman, J.; Hashmall, J.; Natanson, G.; Sedlak, J.

2003-01-01

82

Kinetics of polymer decomposition  

SciTech Connect

Thermal decomposition rates at heating rates ranging from 5 to 60/sup 0/C/min are reported for 11 polymers. Rates were measured using a Rock Eval II apparatus, which uses a flame ionization detector to detect total evolved non-oxygenated carbon. Reaction rates were fitted to a variety of kinetic models, some involving distributions of activation energies. We found that poly(methyl methacrylate), poly(ethyl methacrylate), and poly(vinyl acetate) required two distinct reactions, which we assumed to be parallel. Many of the polymers did not fit well to any of the rate laws considered. One common problem was that the reaction profile was narrower than a first order reaction with an activation energy that matches the shift of T/sub max/ with heating rate, but it was often not the correct shape to be fitted satisfactorily by an nth-order reaction. We compare our observations with results for one Green River shale, whose decomposition is also sharper than a single first-order reaction, but whose profile is compatible with a fractional-order reaction. We discuss the implications of these problems on the ability to estimate decomposition rates at greatly different thermal histories. 20 refs., 7 figs., 5 tabs.

Burnham, A.K.; Braun, R.L.

1987-12-01

83

Ultra-Fast Flash Observatory for the observation of early photons from gamma-ray bursts  

NASA Astrophysics Data System (ADS)

One of the least documented and understood aspects of gamma-ray bursts (GRBs) is the rise phase of the optical light curve. The Ultra-Fast Flash Observatory (UFFO) is an effort to address this question through extraordinary opportunities presented by a series of space missions including a small spacecraft observatory. The UFFO is equipped with a fast-response Slewing Mirror Telescope (SMT) that uses a rapidly moving mirror or mirror array to redirect the optical beam rather than slewing the entire spacecraft to aim the optical instrument at the GRB position. The UFFO will probe the early optical rise of GRBs with sub-second response, for the first time, opening a completely new frontier in GRBs and transient studies. Its fast response measurements of the optical emission of dozens of GRBs each year will provide unique probes of the burst mechanism and test the prospect of GRBs as a new standard candle, potentially opening up the z > 10 universe. For the first time we employ a motorized slewing stage in SMT that can point to the event within 1 s after the x-ray trigger provided by the UFFO Burst Alert and Trigger Telescope. These two scientific instruments comprise the UFFO-pathfinder payload, which will be placed onboard the Lomonosov satellite and launched in 2013. The UFFO-pathfinder is the first step of our long-term program of space instruments for rapid-response GRB observations. We describe early photon science, our soon-to-be-launched UFFO-pathfinder hardware and mission, and our next planned mission, the UFFO-100.

Park, I. H.; Brandt, S.; Budtz-Jørgensen, C.; Castro-Tirado, A. J.; Chen, P.; Connell, P.; Eyles, C.; Grossan, B.; Huang, M.-H. A.; Jeong, S.; Jung, A.; Kim, J. E.; Kim, S.-W.; Lee, J.; Lim, H.; Linder, E. V.; Liu, T.-C.; Min, K. W.; Na, G. W.; Nam, J. W.; Panasyuk, M. I.; Reglero, V.; Ripa, J.; Rodrigo, J. M.; Smoot, G. F.; Svertilov, S.; Vedenkin, N.; Yashin, I.

2013-02-01

84

Early and efficient detection of Mycobacterium tuberculosis in sputum by microscopic observation of broth cultures.  

PubMed

Early, efficient and inexpensive methods for the detection of pulmonary tuberculosis are urgently needed for effective patient management as well as to interrupt transmission. These methods to detect M. tuberculosis in a timely and affordable way are not yet widely available in resource-limited settings. In a developing-country setting, we prospectively evaluated two methods for culturing and detecting M. tuberculosis in sputum. Sputum samples were cultured in liquid assay (micro broth culture) in microplate wells and growth was detected by microscopic observation, or in Löwenstein-Jensen (LJ) solid media where growth was detected by visual inspection for colonies. Sputum samples were collected from 321 tuberculosis (TB) suspects attending Bugando Medical Centre, in Mwanza, Tanzania, and were cultured in parallel. Pulmonary tuberculosis cases were diagnosed using the American Thoracic Society diagnostic standards. There were a total of 200 (62.3%) pulmonary tuberculosis cases. Liquid assay with microscopic detection detected a significantly higher proportion of cases than LJ solid culture: 89.0% (95% confidence interval [CI], 84.7% to 93.3%) versus 77.0% (95% CI, 71.2% to 82.8%) (p?=?0.0007). The median turn around time to diagnose tuberculosis was significantly shorter for micro broth culture than for the LJ solid culture, 9 days (interquartile range [IQR] 7-13), versus 21 days (IQR 14-28) (p<0.0001). The cost for micro broth culture (labor inclusive) in our study was US $4.56 per sample, versus US $11.35 per sample for the LJ solid culture. The liquid assay (micro broth culture) is an early, feasible, and inexpensive method for detection of pulmonary tuberculosis in resource limited settings. PMID:23469014

Kidenya, Benson R; Kabangila, Rodrick; Peck, Robert N; Mshana, Stephen E; Webster, Lauren E; Koenig, Serena P; Johnson, Warren D; Fitzgerald, Daniel W

2013-01-01

85

Characteristics of long recovery early VLF events observed by the North African AWESOME Network  

NASA Astrophysics Data System (ADS)

Lightning strokes are capable of initiating disturbances in the lower ionosphere, whose recoveries persist for many minutes. These events are remotely sensed via monitoring subionospherically propagating very low frequency (VLF) transmitter signals, which are perturbed as they pass through the region above the lightning stroke. In this paper we describe the properties and characteristics of the early VLF signal perturbations, which exhibit long recovery times using subionospheric VLF transmitter data from three identical receivers located at Algiers (Algeria), Tunis (Tunisia), and Sebha (Libya). The results indicate that the observation of long recovery events depends strongly on the modal structure of the signal electromagnetic field and the distance from the disturbed region and the receiver or transmitter locations. Comparison of simultaneously collected data at the three sites indicates that the role of the causative lightning stroke properties (e.g., peak current and polarity), or that of transient luminous events may be much less important. The dominant parameter which determines the duration of the recovery time and amplitude appears to be the modal structure of the subionospheric VLF probe signal at the ionospheric disturbance, where scattering occurs, and the subsequent modal structure that propagates to the receiver location.

Naitamor, S.; Cohen, M. B.; Cotts, B. R. T.; Ghalila, H.; Alabdoadaim, M. A.; Graf, K.

2013-08-01

86

Early healing after ridge preservation with a new collagen matrix in dog extraction sockets: preliminary observations.  

PubMed

The aim of the present animal study was to investigate the early healing processes developing in the post-extraction sockets preserved with a new-marketed collagen matrix as, to our knowledge, such investigations have not been reported so far. In both quadrants of the mandible of a mongrel dog, the distal sockets of the second premolars served as experimental sites for ridge preservation. The experimental site 1 was protected with a resorbable membrane and then with the collagen matrix. The experimental site 2 was filled with a xenograft and then covered with the collagen matrix. The samples were harvested after one month of healing. In both experimental sites, the bundle bone lining the inner surface of the alveolus was replaced with trabecular bone containing areas of woven bone. A continuous layer of osteoblasts could be observed on the surface of woven bone areas. Osteoclasts encased within resorptive lacunae lined the outer portions of bone walls for the experimental site 1. The trabecular bone occupied only the apical third of the socket in experimental site 1, but it was obviously more abundant in the experimental site 2, occupying also the central compartment of the socket. Moreover, the trabeculae of the bone occupying the inner area of the alveolus were thicker for the experiment site 2 than for experiment site 1, suggesting an increased osseous deposition in the latter situation. Our preliminary results suggest that the association collagen matrix plus xenograft may be a valuable method for ridge preservation. PMID:23529319

Cioban, C; Z?g?nescu, Raluca; Roman, Alexandra; Muste, A; Beteg, F; Câmpian, R S; Bo?ca, Bianca

2013-01-01

87

Constraint on the early Universe by relic gravitational waves: From pulsar timing observations  

SciTech Connect

Recent pulsar timing observations by the Parkers Pulsar Timing Array (PPTA) and European Pulsar Timing Array (EPTA) teams obtained the constraint on the relic gravitational waves at the frequency f{sub *}=1/yr, which provides the opportunity to constrain H{sub *}, the Hubble parameter, when these waves crossed the horizon during inflation. In this paper, we investigate this constraint by considering the general scenario for the early Universe: we assume that the effective (average) equation-of-state w before the big bang nucleosynthesis stage is a free parameter. In the standard hot big-bang scenario with w=1/3, we find that the current PPTA result follows a bound H{sub *{<=}}1.15x10{sup -1}m{sub Pl}, and the EPTA result follows H{sub *{<=}}6.92x10{sup -2}m{sub Pl}. We also find that these bounds become much tighter in the nonstandard scenarios with w>1/3. When w=1, the bounds become H{sub *{<=}}5.89x10{sup -3}m{sub Pl} for the current PPTA and H{sub *{<=}}3.39x10{sup -3}m{sub Pl} for the current EPTA. In contrast, in the nonstandard scenario with w=0, the bound becomes H{sub *{<=}}7.76m{sub Pl} for the current PPTA.

Zhao Wen [Department of Physics, Zhejiang University of Technology, Hangzhou 310014 (China) and Niels Bohr Institute, Copenhagen University, Blegdamsvej 17, Copenhagen DK-2100 (Denmark)

2011-05-15

88

[Leaf litter decomposition and nutrient release of different stand types in a shelter belt in Xinjiang arid area].  

PubMed

From October 2007 to November 2008, an in situ mesh bag experiment was conducted to study the leaf litter decomposition and nutrient release of forest stands Populus alba var. pyramidalis, Amorpha fruticosa, and P. alba var. pyramidalis + A. fruticosa in a shelter belt in Karamay, Xinjiang. It was observed that the mass loss rate of leaf litter differed with tree species, and was significantly affected by leaf litter composition. The leaf litter of P. alba var. pyramidalis + A. fruticosa was more easily decomposed than that of the other two mono-dominance forest trees. The analysis with improved Olson' s exponential model indicated that P. alba var. pyramidalis leaf litter had the lowest decomposition coefficient (k = 0.167), while P. alba var. pyramidalis + A. fruticosa leaf litter had the highest one (k = 0.275). According to the model, it would cost for about 2.41-4.19 years and 10.79-17.98 years to have 50% and 95% decomposition of the three kind leaf litters, respectively. The residual rates of nitrogen, phosphorus, and potassium in the three kind leaf litters differed with decomposition period. After one year decomposition, potassium was wholly released, while nitrogen and phosphorus were immobilized or enriched via the absorption from surrounding environment. Except that the A. fruticosa leaf litter had a decreased organic carbon decomposition rate in the mid period of decomposition, the leaf litters of P. alba var. pyramidalis and P. alba var. pyramidalis + A. fruticosa all had an increasing organic carbon decomposition rate with the decomposition, which was about 35.5%-44.2% after one year decomposition. The C/N value of the leaf litters had a decreasing trend, and the decrement was smaller in the early and mid periods but larger in the late period of decomposition. PMID:21941735

Yang, Yu-Hai; Zheng, Lu; Duan, Yong-Zhao

2011-06-01

89

Observing the Cosmic Microwave Background Radiation: A Unique Window on the Early Universe  

Microsoft Academic Search

The cosmic microwave background radiation is the remnant heat from the Big Bang. It provides us with a unique probe of conditions in the early universe, long before any organized structures had yet formed. The anisotropy in the radiation's brightness yields important clues about primordial structure and additionally provides a wealth of information about the physics of the early universe.

Gary Hinshaw

2001-01-01

90

Reading, Reasoning, and Literacy: Strategies for Early Childhood Education from the Analysis of Classroom Observations  

ERIC Educational Resources Information Center

Researchers have posited that children generally learn to read in environments that are trusting, comfortable, and offer small group or one-to-one adult support, all of which are characteristics of a high quality early childhood education program. This evaluation research study examines the Pre-Kindergarten Incentive Program, an early childhood…

McKie, Brooke K.; Manswell Butty, Jo-Anne; Green, Rodney D.

2012-01-01

91

Titan: Preliminary results on surface properties and photometry from VIMS observations of the early flybys  

USGS Publications Warehouse

Cassini observations of the surface of Titan offer unprecedented views of its surface through atmospheric windows in the 1-5 ??m region. Images obtained in windows for which the haze opacity is low can be used to derive quantitative photometric parameters such as albedo and albedo distribution, and physical properties such as roughness and particle characteristics. Images from the early Titan flybys, particularly T0, Ta, and T5 have been analyzed to create albedo maps in the 2.01 and 2.73 ??m windows. We find the average normal reflectance at these two wavelengths to be 0.15??0.02 and 0.035??0.003, respectively. Titan's surface is bifurcated into two albedo regimes, particularly at 2.01 ??m. Analysis of these two regimes to understand the physical character of the surface was accomplished with a macroscopic roughness model. We find that the two types of surface have substantially different roughness, with the low-albedo surface exhibiting mean slope angles of ???18??, and the high-albedo terrain having a much more substantial roughness with a mean slope angle of ???34??. A single-scattering phase function approximated by a one-term Henyey-Greenstein equation was also fit to each unit. Titan's surface is back-scattering (g???0.3-0.4), and does not exhibit substantially different backscattering behavior between the two terrains. Our results suggest that two distinct geophysical domains exist on Titan: a bright region cut by deep drainage channels and a relatively smooth surface. The two terrains are covered by a film or a coating of particles perhaps precipitated from the satellite's haze layer and transported by eolian processes. Our results are preliminary: more accurate values for the surface albedo and physical parameters will be derived as more data is gathered by the Cassini spacecraft and as a more complete radiative transfer model is developed from both Cassini orbiter and Huygens Lander measurements. ?? 2006 Elsevier Ltd. All rights reserved.

Buratti, B. J.; Sotin, C.; Brown, R. H.; Hicks, M. D.; Clark, R. N.; Mosher, J. A.; McCord, T. B.; Jaumann, R.; Baines, K. H.; Nicholson, P. D.; Momary, T.; Simonelli, D. P.; Sicardy, B.

2006-01-01

92

Nearby early-type galaxies with ionized gas: the UV emission from GALEX observations  

NASA Astrophysics Data System (ADS)

We present GALEX far-ultraviolet (FUV, ?eff= 1538Å) and near-ultraviolet (NUV, ?eff= 2316Å) surface photometry of 40 early-type galaxies (ETGs) selected from a wider sample of 65 nearby ETGs showing emission lines in their optical spectra. We derive FUV and NUV surface brightness profiles, (FUV-NUV) colour profiles and D25 integrated magnitudes. We extend the photometric study to the optical r band from SDSS imaging for 14 of these ETGs. In general, the (FUV-NUV) radial colour profiles become redder with galactocentric distance in both rejuvenated (?4 Gyr) and old ETGs. Colour profiles of NGC 1533, NGC 2962, NGC 2974, NGC 3489 and IC 5063 show rings and/or arm-like structures, bluer than the body of the galaxy, suggesting the presence of recent star formation. Although seven of our ETGs show shell systems in their optical image, only NGC 7135 displays shells in the UV bands. We characterize the UV and optical surface brightness profiles, along the major axis, using a Sersic law. The Sersic law exponent, n, varies from 1 to 16 in the UV bands. S0 galaxies tend to have lower values of n (?5). The Sersic law exponent n= 4 seems to be a watershed: ETGs with n > 4 tend to have [?/Fe] greater than 0.15, implying a short star-formation time-scale. We find a significant correlation between the FUV-NUV colour and central velocity dispersions ?, with the UV colours getting bluer at larger ?. This trend is likely driven by a combined effect of ‘downsizing' and of the mass-metallicity relation. Based on GALEX observations: GI3-0087 PI R. Rampazzo.

Marino, A.; Rampazzo, R.; Bianchi, L.; Annibali, F.; Bressan, A.; Buson, L. M.; Clemens, M. S.; Panuzzo, P.; Zeilinger, W. W.

2011-02-01

93

HUBBLE SPACE TELESCOPE WFC3 EARLY RELEASE SCIENCE: EMISSION-LINE GALAXIES FROM INFRARED GRISM OBSERVATIONS  

SciTech Connect

We present grism spectra of emission-line galaxies (ELGs) from 0.6 to 1.6 {mu}m from the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope. These new infrared grism data augment previous optical Advanced Camera for Surveys G800L 0.6-0.95 {mu}m grism data in GOODS-South from the PEARS program, extending the wavelength coverage well past the G800L red cutoff. The Early Release Science (ERS) grism field was observed at a depth of two orbits per grism, yielding spectra of hundreds of faint objects, a subset of which is presented here. ELGs are studied via the H{alpha}, [O III], and [O II] emission lines detected in the redshift ranges 0.2 {approx}< z {approx}< 1.4, 1.2 {approx}< z {approx}< 2.2, and 2.0 {approx}< z {approx}< 3.3, respectively, in the G102 (0.8-1.1 {mu}m; R {approx_equal} 210) and G141 (1.1-1.6 {mu}m; R {approx_equal} 130) grisms. The higher spectral resolution afforded by the WFC3 grisms also reveals emission lines not detectable with the G800L grism (e.g., [S II] and [S III] lines). From these relatively shallow observations, line luminosities, star formation rates, and grism spectroscopic redshifts are determined for a total of 48 ELGs to m A{sub B(F098M)} {approx_equal} 25 mag. Seventeen GOODS-South galaxies that previously only had photometric redshifts now have new grism-spectroscopic redshifts, in some cases with large corrections to the photometric redshifts ({Delta}z {approx_equal} 0.3-0.5). Additionally, one galaxy had no previously measured redshift but now has a secure grism-spectroscopic redshift, for a total of 18 new GOODS-South spectroscopic redshifts. The faintest source in our sample has a magnitude m{sub AB(F098M)}= 26.9 mag. The ERS grism data also reflect the expected trend of lower specific star formation rates for the highest mass galaxies in the sample as a function of redshift, consistent with downsizing and discovered previously from large surveys. These results demonstrate the remarkable efficiency and capability of the WFC3 NIR grisms for measuring galaxy properties to faint magnitudes and redshifts to z {approx}> 2.

Straughn, Amber N.; Gardner, Jonathan P. [Astrophysics Science Division, Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States); Kuntschner, Harald; Kuemmel, Martin; Walsh, Jeremy R. [Space Telescope European Coordinating Facility, Karl Schwarzschild Str. 2, D 85748 Garching (Germany); Cohen, Seth H.; Windhorst, Rogier A.; Malhotra, Sangeeta; Rhoads, James [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States); O'Connell, Robert W. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904-4325 (United States); Pirzkal, Norbert; Bond, Howard E. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Meurer, Gerhardt [International Centre for Radio Astronomy Research, University of Western Australia, Crawley, WA 6009 (Australia); McCarthy, Patrick J. [Observatories of the Carnegie Institute of Washington, Pasadena, CA 91101 (United States); Hathi, Nimish P. [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States); Balick, Bruce [Department of Astronomy, University of Washington, Seattle, WA 98195-1580 (United States); Calzetti, Daniela [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Disney, Michael J. [School of Physics and Astronomy, Cardiff University, Cardiff, CF24 3AA (United Kingdom); Dopita, Michael A. [Research School of Astronomy and Astrophysics, Australian National University, ACT 2611 (Australia); Frogel, Jay A., E-mail: amber.n.straughn@nasa.gov [Association of Universities for Research in Astronomy, Washington, DC 20005 (United States)

2011-01-15

94

Decomposition of Sodium Tetraphenylborate.  

National Technical Information Service (NTIS)

The chemical decomposition of aqueous alkaline solutions of sodium tetraphenylborate (NaTPB) has been investigated. The focus of the investigation is on the determination of additives and/or variables which influence NaTBP decomposition. This document des...

M. J. Barnes

1998-01-01

95

Probability Matrix Decomposition Models.  

ERIC Educational Resources Information Center

Generalizing Boolean matrix decomposition to a larger class of matrix decomposition models is demonstrated, and probability matrix decomposition (PMD) models are introduced as a probabilistic version of the larger class. An algorithm is presented for the computation of maximum likelihood and maximum a posteriori estimates of the parameters of PMD…

Maris, Eric; And Others

1996-01-01

96

Chemiluminescence of Organic Peroxide Decomposition  

Microsoft Academic Search

The thermal decomposition of organic hydroperoxides in solution gives rise to weak chemiluminescence effects. One emission, which has a maximum at a wavelength longer than 5500 Å, seems chiefly, if not entirely, a surface effect. With hydroperoxides having aromatic nuclei a blue emission from the liquid volume is observed. The nature of the light-emitting processes is discussed.

E. J. Bowen; R. A. Lloyd

1963-01-01

97

Conflict resolution and children’s behaviour: observing and understanding social and cooperative play in early years educational settings  

Microsoft Academic Search

This paper draws from continuing research into the growth of sociability and cooperation in young children. It began in the mid?1980s and has continued periodically in a range of early years educational settings across the 3–6 age range. The research has underpinned the development of an observational tool. This tool – the Social Play Continuum or SPC – has been

Pat Broadhead

2009-01-01

98

An overview of the Cosmic Background Explorer (COBE) and its observations - New sky maps of the early universe  

Microsoft Academic Search

This paper discusses the three instruments aboard NASA's Cosmic Background Explorer (COBE) satellite and presents early results obtained from the first six months of observations. The three instruments (FIRAS, DMR, and DIRBE) have operated well and produced significant new results. The FIRAS measurement of the CMB spectrum supports the standard Big Bang model. The maps made from the DMR instrument

George F. Smoot

1992-01-01

99

Conflict Resolution and Children's Behaviour: Observing and Understanding Social and Cooperative Play in Early Years Educational Settings  

ERIC Educational Resources Information Center

This paper draws from continuing research into the growth of sociability and cooperation in young children. It began in the mid-1980s and has continued periodically in a range of early years educational settings across the 3-6 age range. The research has underpinned the development of an observational tool. This tool--the Social Play Continuum or…

Broadhead, Pat

2009-01-01

100

Cosmic Background Explorer (COBE) observations: new sky maps of the early universe  

Microsoft Academic Search

This paper presents early results obtained from the first six months of measurements of the Cosmic Microwave Background (CMB) by instruments aboard NASA's Cosmic Background Explorer (COBE) satellite and discusses the implications for cosmology. The three instruments: FIRAS, DMR, and DIRBE have operated well and produced significant new results. The FIRAS measurement of the CMB spectrum supports the standard Big

G. F. Smoot

1991-01-01

101

Early Metalinguistic Awareness of Derivational Morphology: Observations from a Comparison of English and French  

ERIC Educational Resources Information Center

This cross-linguistic comparison of metalinguistic development in French and English examines early ability to manipulate derivational suffixes in oral language games as a function of chronological age, receptive vocabulary, and year of schooling. Data from judgment and production tasks are presented for children aged between 5 and 8 years in…

Duncan, Lynne G.; Casalis, Severine; Cole, Pascale

2009-01-01

102

Small-scale early aggregation of green tide macroalgae observed on the Subei Bank, Yellow Sea.  

PubMed

Massive green algae blooms became an environmental disaster in the Yellow Sea from 2008 to 2013. Recent studies suggested that recurrences of early aggregates of macroalgae were found over the Subei Bank, a unique shallow radial sand ridge system off the Jiangsu coast, China. Yearly field surveys have been carried out over this bank during the past five years (2009-2013), with an aim at identifying and qualifying the physical-biological mechanism for the early aggregation of algae. Data synthesis showed that early aggregation of macroalgae usually occurred from April-May as small-scale patches either over the intertidal mudflat of the Subei Bank or along local isobaths in the northern coastal area north of the bank. Both hydrographic and current measurements were performed by tracking a narrow patchy area of floating macroalgae (nearly 4 km in length and 5-10 m in width) on April 26, 2013, and the results showed that the algae aggregation was mainly caused by tide-induced convergence. This convergence was produced by the local geometrically controlled interaction of tidal currents with mudflats, which is believed to be a key physical mechanism for the early development of algal blooms in addition to marine ecosystem responses and human aquaculture activities. PMID:24569106

Hu, Song; Yang, Hong; Zhang, Jianheng; Chen, Changsheng; He, Peimin

2014-04-15

103

Thermal decomposition products of butyraldehyde  

NASA Astrophysics Data System (ADS)

The thermal decomposition of gas-phase butyraldehyde, CH3CH2CH2CHO, was studied in the 1300-1600 K range with a hyperthermal nozzle. Products were identified via matrix-isolation Fourier transform infrared spectroscopy and photoionization mass spectrometry in separate experiments. There are at least six major initial reactions contributing to the decomposition of butyraldehyde: a radical decomposition channel leading to propyl radical + CO + H; molecular elimination to form H2 + ethylketene; a keto-enol tautomerism followed by elimination of H2O producing 1-butyne; an intramolecular hydrogen shift and elimination producing vinyl alcohol and ethylene, a ?-C-C bond scission yielding ethyl and vinoxy radicals; and a ?-C-C bond scission yielding methyl and CH2CH2CHO radicals. The first three reactions are analogous to those observed in the thermal decomposition of acetaldehyde, but the latter three reactions are made possible by the longer alkyl chain structure of butyraldehyde. The products identified following thermal decomposition of butyraldehyde are CO, HCO, CH3CH2CH2, CH3CH2CH=C=O, H2O, CH3CH2C?CH, CH2CH2, CH2=CHOH, CH2CHO, CH3, HC?CH, CH2CCH, CH3C?CH, CH3CH=CH2, H2C=C=O, CH3CH2CH3, CH2=CHCHO, C4H2, C4H4, and C4H8. The first ten products listed are direct products of the six reactions listed above. The remaining products can be attributed to further decomposition reactions or bimolecular reactions in the nozzle.

Hatten, Courtney D.; Kaskey, Kevin R.; Warner, Brian J.; Wright, Emily M.; McCunn, Laura R.

2013-12-01

104

Thermal decomposition products of butyraldehyde.  

PubMed

The thermal decomposition of gas-phase butyraldehyde, CH3CH2CH2CHO, was studied in the 1300-1600 K range with a hyperthermal nozzle. Products were identified via matrix-isolation Fourier transform infrared spectroscopy and photoionization mass spectrometry in separate experiments. There are at least six major initial reactions contributing to the decomposition of butyraldehyde: a radical decomposition channel leading to propyl radical + CO + H; molecular elimination to form H2 + ethylketene; a keto-enol tautomerism followed by elimination of H2O producing 1-butyne; an intramolecular hydrogen shift and elimination producing vinyl alcohol and ethylene, a ?-C-C bond scission yielding ethyl and vinoxy radicals; and a ?-C-C bond scission yielding methyl and CH2CH2CHO radicals. The first three reactions are analogous to those observed in the thermal decomposition of acetaldehyde, but the latter three reactions are made possible by the longer alkyl chain structure of butyraldehyde. The products identified following thermal decomposition of butyraldehyde are CO, HCO, CH3CH2CH2, CH3CH2CH=C=O, H2O, CH3CH2C?CH, CH2CH2, CH2=CHOH, CH2CHO, CH3, HC?CH, CH2CCH, CH3C?CH, CH3CH=CH2, H2C=C=O, CH3CH2CH3, CH2=CHCHO, C4H2, C4H4, and C4H8. The first ten products listed are direct products of the six reactions listed above. The remaining products can be attributed to further decomposition reactions or bimolecular reactions in the nozzle. PMID:24320376

Hatten, Courtney D; Kaskey, Kevin R; Warner, Brian J; Wright, Emily M; McCunn, Laura R

2013-12-01

105

An Observational Study on Early Empiric versus Culture-Directed Antifungal Therapy in Critically Ill with Intra-Abdominal Sepsis  

PubMed Central

Objective. To compare early empiric antifungal treatment with culture-directed treatment in critically ill patients with intra-abdominal sepsis. Methods. A prospective observational cohort study was conducted between August 2010 and July 2011, on SICU patients admitted after surgery for gastrointestinal perforation, bowel obstruction or ischemia, malignancy and anastomotic leakages. Patients who received antifungal treatment within two days of sepsis onset were compared to patients who received culture-directed antifungal treatment in terms of mortality rate and clinical improvement. Patients' demographics, comorbidities, severity-of-illness scores, and laboratory results were systematically collected and analysed. Results. Thirty-three patients received early empiric and 19 received culture-directed therapy. Of these, 30 from the early empiric group and 18 from culture-directed group were evaluable and analysed. Both groups had similar baseline characteristics and illness severity. Patients on empiric antifungal use had significantly lower 30-day mortality (P = 0.03) as well as shorter median time to clinical improvement (P = 0.025). Early empiric antifungal therapy was independently associated with survival beyond 30 days (OR 0.131, 95% CI: 0.018 to 0.966; P = 0.046). Conclusion. Early empiric antifungal therapy in surgical patients with intra-abdominal sepsis was associated with reduced mortality and warrants further evaluation in randomised controlled trials.

Lee, Winnie; Liew, Yixin; Chlebicki, Maciej Piotr; Ong, Sharon; Lee, Pang; Kwa, Andrea

2014-01-01

106

Low-energy reaction rate constants for the Ni+-assisted decomposition of acetaldehyde: observation of C-H and C-C activation.  

PubMed

Rate constants for the low-energy Ni(+)-assisted dissociative reaction of acetaldehyde have been measured under jet-cooled conditions in the gas phase. The rate constants are acquired through monitoring the time dependence of fragment Ni(+)CO formation. The decomposition of the precursor Ni(+)-acetaldehyde cluster ion proceeds via consecutive, parallel reaction coordinates that originate with the Ni(+)-assisted cleavage of either a C-C or an aldehyde C-H bond. The energies used to initiate these reactions are well below that required to cleave sigma-bonds in the isolated acetaldehyde molecule. Direct measurement of the reaction kinetics over a range of energies indicates that the rate-limiting step in the dissociative mechanism changes at cluster ion internal energies = 17,200 +/- 400 cm(-1). Arguments are presented that this energy marks the closure of the dissociative coordinate that initiates with C-H sigma-bond activation and thus provides a measure of the activation energy of this dissociative pathway. PMID:20050634

Dee, S Jason; Castleberry, Vanessa A; Villarroel, Otsmar J; Laboren, Ivanna E; Bellert, Darrin J

2010-02-01

107

Erbium hydride decomposition kinetics.  

SciTech Connect

Thermal desorption spectroscopy (TDS) is used to study the decomposition kinetics of erbium hydride thin films. The TDS results presented in this report are analyzed quantitatively using Redhead's method to yield kinetic parameters (E{sub A} {approx} 54.2 kcal/mol), which are then utilized to predict hydrogen outgassing in vacuum for a variety of thermal treatments. Interestingly, it was found that the activation energy for desorption can vary by more than 7 kcal/mol (0.30 eV) for seemingly similar samples. In addition, small amounts of less-stable hydrogen were observed for all erbium dihydride films. A detailed explanation of several approaches for analyzing thermal desorption spectra to obtain kinetic information is included as an appendix.

Ferrizz, Robert Matthew

2006-11-01

108

Is the ratio of observed X-ray luminosity to bolometric luminosity in early-type stars really a constant?  

NASA Technical Reports Server (NTRS)

The observed X-ray emission from early-type stars can be explained by the recombination stellar wind model (or base coronal model). The model predicts that the true X-ray luminosity from the base coronal zone can be 10 to 1000 times greater than the observed X-ray luminosity. From the models, scaling laws were found for the true and observed X-ray luminosities. These scaling laws predict that the ratio of the observed X-ray luminosity to the bolometric luminosity is functionally dependent on several stellar parameters. When applied to several other O and B stars, it is found that the values of the predicted ratio agree very well with the observed values.

Waldron, W. L.

1985-01-01

109

The 3-D effects in the long-term solar wind speed rise observed by Voyager 2 in early 1994  

Microsoft Academic Search

In early 1994, Voyager 2 at 42-43 AU near heliolatitude 10 deg S observed over a period of approximately 100 days a remarkable sequence of quasi-recurrent stream fronts, wherein the background (ambient) speed rose steadily from approximately 450 to approximately 550 km\\/s while the mean period of the streams decreased from the usual 25 days down to approximately 20 days.

V. J. Pizzo; K. I. Paularena; J. D. Richardson; A. J. Lazarus; J. W. Belcher

1995-01-01

110

Newly observed several peroxides from the gas phase ozonolysis of isoprene using a flow tube reactor and the water vapor effect on their formation and decomposition  

NASA Astrophysics Data System (ADS)

In recent years, one has been paying more and more attention to the formation of hydrogen peroxide and organic peroxides in the oxidation of volatile organic compounds (VOCs) because peroxides play important roles, such as reservoir of OH, HO2 and RO2 radicals, intermediate of Criegee radical chemistry and contributor to secondary organic aerosol. However, to the best of our knowledge, in the reaction of ozone with VOCs, only several small peroxides such as hydrogen peroxide (H2O2), hydroxymethyl hydroperoxide (HMHP), and methyl hydroperoxide (MHP) were separately identified, and their yields varied widely between different studies. Moreover, the information on the formation mechanism of peroxides in the ozonolysis of VOCs was mostly from a speculation rather than experimental evidence. Notably, a static chamber was employed in most of the previous studies, potentially resulting in the decomposition and heterogeneous reaction of peroxides on the chamber walls within an experiment time of tens of minutes to several hours, and possibly missing the details about the generation of peroxides. In the present study, we have used a flow quartz tube reactor to investigate the formation of peroxides in the ozonolysis of isoprene at various relative humidities (RH). A variety of peroxides have been detected on the tens of seconds of time scale using an online high performance liquid chromatography coupled with post-column derivatization using p-hydroxyphenylacetic acid and fluorescence detection. Our experimental results show that in addition to the three peroxides mentioned previously, more four ones, those are peroxyacetic acid (PAA) and three unknown peroxides, have been found. Furthermore, the total yield of the three small peroxides (H2O2, HMHP and MHP) is found to be similar to the result of literature; while for PAA and three unknown peroxides, they highlight a combined molar yield, for example, ~ 40% at 5% RH, much higher than that of the three small peroxides. Opposite to the previous conclusion that the peroxide yield would be positively correlated with RH, the yields of PAA and three unknown peroxides detected in the present study decreased with the RH increase. We tentatively assign these unknown peroxides to be hydroxyl hydroperoxides, which are produced by the reaction of different Criegee radicals with water. We used a box model coupled with the MCM v3.2 mechanism to simulate the reaction processes of the ozone-initiated oxidation of isoprene, adding the reaction between the gaseous water (and water dimer) and Criegee radicals and the decomposition of water-assisted hydroxyl hydroperoxides. We find that this modified mechanism would better explain the variation of peroxides with the RH increase, implying that molecular water and water cluster should be involved in the production and removal of peroxides in the future model.

Huang, D.; Chen, Z.; Zhao, Y.

2012-12-01

111

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

Microsoft Academic Search

This short-term longitudinal study (N = 112) was conducted to explore the concurrent and prospective associations between teacher-reported impulsive-hyperactive\\u000a behavior and observed relational and physical aggression during early childhood (M = 45.54 months old, SD = 9.07). Multiple informants and methods including observational methods (i.e., 160 min per child)\\u000a were used to assess aggression and impulsivity-hyperactivity. All measures were found to be valid and reliable. Prospective\\u000a hierarchical regression

Jamie M. Ostrov; Stephanie A. Godleski

2009-01-01

112

Early lidar observations of the June 1991 Pinatubo eruption plume at Mauna Loa Observatory, Hawaii  

Microsoft Academic Search

The Pinatubo plume was first observed by lidar on 1 July 1991. During July and August the observable effects from this plume increased in intensity in terms of aerosol optical properties, plume height, and broad-band solar radiation. Preliminary data analysis shows that the plume over Hawaii arrived in three generalized pulses or waves on approximately 3 July, 24 July, and

Thomas E. Defoor; Elmer Robinson; Steven Ryan

1992-01-01

113

Using Videoconferencing Technology to Enhance Classroom Observation Methodology for the Instruction of Preservice Early Childhood Professionals  

ERIC Educational Resources Information Center

To learn about and become acclimated to the environment in which they someday plan to work, preservice teachers and pre-professional daycare providers are typically required to conduct onsite observations. Traditionally, these observations require that the pre-professional spend a required number of hours studying the dynamics of the real-world…

Pickering, Lloyd E.; Walsh, Eamonn Joseph

2011-01-01

114

A Study in Early Speech Development: A Preliminary Approach for Systematic Observation. (RIEEC Research Bulletin 4).  

ERIC Educational Resources Information Center

A normal Japanese boy (11-months-old) was observed while playing alone and while interacting with his mother to study the child's physical and vocal imitation and to determine the relationship between his use of physical (nonverbal) and vocal (verbal) communication. During 10 free play sessions, four observers noted occurrences of such behavior as…

Iitaka, Kyoko A.

115

Assessing the remote sensing derived Evaporative Stress Index with ground observations of crop condition to advance drought early warning  

NASA Astrophysics Data System (ADS)

Drought has significant impacts over broad spatial and temporal scales, and information about the timing and extent of such conditions is of critical importance to many end users in the agricultural and water resource management communities. The ability to accurately monitor effects on crops, and provide early warning of developing vegetation stress, will provide valuable information for mitigating negative impacts of drought. This research assesses the potential of the thermal remote sensing based Evaporative Stress Index (ESI) as a relatively early indication of declining crop condition using county level crop condition (CC) and soil moisture (SM) weekly reports from the USDA National Agricultural Statistics Service (NASS) collected by trained observers on the ground in crop growing counties in the contiguous United States (CONUS). Spatial and temporal correlations between these datasets will be explored over a variety of temporal and spatial scales, as well as for different crop types and phenologic stages. Preliminary analysis shows that monthly ESI agrees well with the ground observations, suggesting the ESI as a valuable, spatially continuous dataset for improving drought modeling efforts. In addition, stress-induced changes in ESI are hypothesized to precede declines in crop cover fraction, typically observed using optical vegetation indices such as the Normalized Difference Vegetation Index. Increases in canopy and soil temperatures (detectable via thermal remote sensing) are hypothesized to occur before crop biomass is visibly affected by soil moisture depletion. Spatiotemporal agreement between NASS CC and SM observations, gridded over CONUS, will be assessed in comparison with ESI data fields and other standard drought indictors to identify optimal indices for early detection of degrading crop conditions. Analysis over the time period 2002-2013 will allow the relationships to be assessed in a variety of climatological conditions (i.e. wet and dry years, etc.). This research, by comparing both remote sensing and ground observations, provides a unique and valuable perspective of evapotranspiration and drought estimation with implications for modeling and operational decision making.

Semmens, K. A.; Anderson, M. C.; Mladenova, I. E.; Hain, C.; Otkin, J.; Guindin, N.

2013-12-01

116

Direct Observation of Early-Time Hydrogelation in ?-Hairpin Peptide Self-Assembly  

NASA Astrophysics Data System (ADS)

Triggered hydrogelation of MAX 1 peptide (NH2-(VK)4-V^DPPT-(KV)4-CONH2) proceeds through peptide intramolecular folding into ?-hairpins and immediate self-assembly into branched clusters of well defined (uniform, 3 nm cross section), semi-flexible, ?-sheet-rich nanofibrils. Cryogenic transmission electron microscopy indicates that dangling fibrils extend from one growing cluster to another and lead to early, intercluster communication in solution. At the apparent percolation threshold, the dynamic shear modulus measured by oscillatory rheology (G'(?),G"(?)?^n) and the field-intensity autocorrelation function measured by dynamic light scattering (g1(?)?^-?') show power-law behavior with comparable critical dynamic exponents (n 0.47 and ?' 0.45). Finite interpenetration of percolating cluster with smaller clusters, along with permanent intercluster entanglements, increase the network rigidity. The self-assembly of MAX 1 peptide was compared and contrasted with the assembly of other biopolymeric networks in literature.

Yucel, Tuna; Schneider, Joel; Pochan, Darrin

2008-03-01

117

Direct Observation of Early-Time Hydrogelation in ?-Hairpin Peptide Self-Assembly  

PubMed Central

Triggered hydrogelation of MAX1 peptide, (VK)4-VDPPT-(KV)4-NH2, proceeds through peptide intramolecular folding into ?-hairpins and concomitant self-assembly into branched clusters of well-defined (uniform, 3 nm cross section), semiflexible, ?-sheet-rich nanofibrils. Cryogenic transmission electron microscopy indicates that dangling fibrils extend from one growing cluster to another and lead to early, intercluster communication in solution. At the apparent percolation threshold, the dynamic shear modulus measured by oscillatory rheology (G?(?), G?(?) ? ?n) and the field-intensity autocorrelation function measured by dynamic light scattering (g1(?) ? ?-??) show power-law behavior with comparable critical dynamic exponents (n ? 0.47 and ?? ? 0.45). Finite interpenetration of percolating clusters with smaller clusters, along with permanent intercluster entanglements, increase the network rigidity. The self-assembly of MAX1 peptide was compared and contrasted with the assembly of other biopolymeric networks in literature.

Yucel, Tuna; Micklitsch, Chris M.; Schneider, Joel P.; Pochan, Darrin J.

2009-01-01

118

Anemia after gastrectomy for early gastric cancer: Long-term follow-up observational study  

PubMed Central

AIM: To identify the incidence and etiology of anemia after gastrectomy in patients with long-term follow-up after gastrectomy for early gastric cancer. METHODS: The medical records of those patients with early gastric adenocarcinoma who underwent curative gastrectomy between January 2006 and October 2007 were reviewed. Patients with anemia in the preoperative workup, cancer recurrence, undergoing systemic chemotherapy, with other medical conditions that can cause anemia, or treated during follow up with red cell transfusions or supplements for anemia were excluded. Anemia was defined by World Health Organization criteria (Hb < 12 g/dL in women and < 13 g/dL in men). Iron deficiency was defined as serum ferritin < 20 ?g/dL. Vitamin B12 deficiency was defined as serum vitamin B12 < 200 pg/mL. Iron deficiency anemia was defined as anemia with concomitant iron deficiency. Anemia from vitamin B12 deficiency was defined as megaloblastic anemia (mean cell volume > 100 fL) with vitamin B12 deficiency. The profile of anemia over 48 mo of follow-up was analyzed. RESULTS: One hundred sixty-one patients with gastrectomy for early gastric cancer were analyzed. The incidence of anemia was 24.5% at 3 mo after surgery and increased up to 37.1% at 48 mo after surgery. The incidence of iron deficiency anemia increased during the follow up and became the major cause of anemia at 48 mo after surgery. Anemia of chronic disease and megaloblastic anemia were uncommon. The incidence of anemia in female patients was significantly higher than in male patients at 12 (40.0% vs 22.0%, P = 0.033), 24 (45.0% vs 25.0%, P = 0.023), 36 (55.0% vs 28.0%, P = 0.004), and 48 mo (52.0% vs 31.0%, P = 0.022) after surgery. Patients with total gastrectomy showed significantly higher incidence of anemia than patients with subtotal gastrectomy at 48 mo after surgery (60.7% vs 31.3%, P = 0.008). The incidence of iron deficiency was significantly higher in female patients than in male patients at 6 (35.4% vs 13.3%, P = 0.002), 12 (45.8% vs 16.8%, P < 0.001), 18 (52.1% vs 22.3%, P < 0.001), 24 (60.4% vs 20.9%, P < 0.001), 36 (62.5% vs 29.2%, P < 0.001), and 48 mo (66.7% vs 34.7%, P = 0.001) after surgery. CONCLUSION: Anemia was frequent after gastrectomy for early gastric cancer, with iron deficiency being the major cause. Evaluation for anemia including iron status should be performed after gastrectomy and appropriate iron replacement should be considered.

Lim, Chul-Hyun; Kim, Sang Woo; Kim, Won Chul; Kim, Jin Soo; Cho, Yu Kyung; Park, Jae Myung; Lee, In Seok; Choi, Myung-Gyu; Song, Kyo-Young; Jeon, Hae Myung; Park, Cho-Hyun

2012-01-01

119

Excess Optical Enhancement Observed with ARCONS for Early Crab Giant Pulses  

NASA Astrophysics Data System (ADS)

We observe an extraordinary link in the Crab pulsar between the enhancement of an optical pulse and the timing of the corresponding giant radio pulse. At optical through infrared wavelengths, our observations use the high time resolution of ARray Camera for Optical to Near-IR Spectrophotometry, a unique superconducting energy-resolving photon-counting array at the Palomar 200 inch telescope. At radio wavelengths, we observe with the Robert C. Byrd Green Bank Telescope and the Green Bank Ultimate Pulsar Processing Instrument backend. We see an 11.3% ± 2.5% increase in peak optical flux for pulses that have an accompanying giant radio pulse arriving near the peak of the optical main pulse, in contrast to a 3.2% ± 0.5% increase when an accompanying giant radio pulse arrives soon after the optical peak. We also observe that the peak of the optical main pulse is 2.8% ± 0.8% enhanced when there is a giant radio pulse accompanying the optical interpulse. We observe no statistically significant spectral differences between optical pulses accompanied by and not accompanied by giant radio pulses. Our results extend previous observations of optical-radio correlation to the time and spectral domains. Our refined temporal correlation suggests that optical and radio emission are indeed causally linked, and the lack of spectral differences suggests that the same mechanism is responsible for all optical emission.

Strader, M. J.; Johnson, M. D.; Mazin, B. A.; Spiro Jaeger, G. V.; Gwinn, C. R.; Meeker, S. R.; Szypryt, P.; van Eyken, J. C.; Marsden, D.; O'Brien, K.; Walter, A. B.; Ulbricht, G.; Stoughton, C.; Bumble, B.

2013-12-01

120

Ultra-Fast Flash Observatory (uffo) for Observation of Early Photons from Gamma Ray Bursts  

NASA Astrophysics Data System (ADS)

One of the least documented and understood aspects of gamma-ray bursts (GRB) is the rise phase of the optical light curve. The Ultra-Fast Flash Observatory (UFFO) is an effort to address this question through extraordinary opportunities presented by a series of space missions including a small spacecraft observatory. The UFFO is equipped with a fast-response Slewing Mirror Telescope (SMT) which uses rapidly moving mirror or mirror arrays to redirect the optical beam rather than slewing the entire spacecraft to aim the optical instrument at the GRB position. The UFFO will probe the early optical rise of GRBs with a sub-second response, for the first time, opening a completely new frontier in GRB and transient studies, the only GRB system which can point and measure on these time scales. Its fast response measurements of the optical emission of dozens of GRB each year will provide unique probes of the burst mechanism, shock breakouts in core-collapse supernovae, tidal disruptions around black holes, test Lorentz violation, be the electromagnetic counterpart to neutrino and gravitational wave signatures of the violent universe, and verify the prospect of GRB as a new standard candle potentially opening up the z>10 universe. As a first step, we employ a motorized slewing stage in SMT which can point to the event within 1s after X-ray trigger, in the UFFO-pathfinder payload onboard the Lomonosov satellite to be launched in 2012. The pathfinder was a small and limited, yet remarkably powerful micro-observatory for rapid optical response to bright gamma-ray bursts, the first part of our GRB and rapid-response long-term program. We describe the early photon science, the space mission of UFFO-pathfinder, and our plan for the next step.

Park, I. H.; Ahmad, S.; Barrillon, P.; Brandt, S.; Budtz-Jorgensen, C.; Castro-Tirado, A. J.; Chen, P.; Choi, Y. J.; Connell, P.; Dagoret-Campagne, S.; Eyles, C.; Grossan, B.; Huang, M.-H. A.; Jung, A.; Jeong, S.; Kim, J. E.; Kim, M. B.; Kim, S.-W.; Kim, Y. W.; Krasnov, A. S.; Lee1, J.; Lim, H.; Linder, E. V.; Liu, T.-C.; Lund, N.; Min, K. W.; Na, G. W.; Nam, J. W.; Panasyuk, M. I.; Ripa, J.; Reglero, V.; Rodrigo, J. M.; Smoot, G. F.; Suh, J. E.; Svertilov, S.; Vedenkin, N.; Wang, M.-Z.; Yashin, I.

2013-12-01

121

Early-time observations of gamma-ray burst error boxes with the Livermore optical transient imaging system  

SciTech Connect

Despite the enormous wealth of gamma-ray burst (GRB) data collected over the past several years the physical mechanism which causes these extremely powerful phenomena is still unknown. Simultaneous and early time optical observations of GRBs will likely make an great contribution t o our understanding. LOTIS is a robotic wide field-of-view telescope dedicated to the search for prompt and early-time optical afterglows from gamma-ray bursts. LOTIS began routine operations in October 1996 and since that time has responded to over 145 gamma-ray burst triggers. Although LOTIS has not yet detected prompt optical emission from a GRB its upper limits have provided constraints on the theoretical emission mechanisms. Super-LOTIS, also a robotic wide field-of-view telescope, can detect emission 100 times fainter than LOTIS is capable of detecting. Routine observations from Steward Observatory's Kitt Peak Station will begin in the immediate future. During engineering test runs under bright skies from the grounds of Lawrence Livermore National Laboratory Super-LOTIS provided its first upper limits on the early-time optical afterglow of GRBs. This dissertation provides a summary of the results from LOTIS and Super-LOTIS through the time of writing. Plans for future studies with both systems are also presented.

Williams, G G

2000-08-01

122

Mid-Infrared Observational and Theoretical Studies of Star Formation and Early Solar Systems  

NASA Technical Reports Server (NTRS)

The first 2 years of this program were used to make mid-IR observations of regions of star formation in the Orion nebula with the UCSD mid-IR camera at the UCSD/University of Minnesota telescope at Mt. Lemmon. These observations attempted to make the first systematic study of an extended region, known to have newly forming stars, and expected to have complex mid-IR emission. We discovered, to our surprise, that most of the thermal emission originated from extended sources rather than from point sources. This interesting observation made the analysis of the data much more complex, since the chop/nod procedures used at these wavelengths produce a differential measurement of the emission in one region compared to that in the adjacent region. Disentangling complex extended emission in such a situation is very difficult. In parallel with this work we were also observing comets in the thermal infrared, the other component of the original proposal. Some spectacular data on the comet Swift-Tuttle was acquired and published. A changing jet structure observed over a 2 week period is described. The rotation period of the comet can be measured at 66 hours. The size of the nucleus can also be estimated (at 30 km) from the observed excess flux from the nucleus. These data have lead to the development of models describing the action of dust particles of differing sizes and composition leaving the nucleus. The spatial distribution of the predicted IR emission has been compared to the observed jet structures, leading to estimates of both particles sizes, relative amounts of silicate vs organic grains, and the amounts of dust emitted in the jets vs isotopic emission.

Jones, Barbara

1997-01-01

123

Decomposition of Sodium Tetraphenylborate  

SciTech Connect

The chemical decomposition of aqueous alkaline solutions of sodium tetraphenylborate (NaTPB) has been investigated. The focus of the investigation is on the determination of additives and/or variables which influence NaTBP decomposition. This document describes work aimed at providing better understanding into the relationship of copper (II), solution temperature, and solution pH to NaTPB stability.

Barnes, M.J.

1998-11-20

124

Observations of Nucleation and Early Stage Growth of Amorphous Silica on Carboxyl-Terminated Model Biosubstrates  

NASA Astrophysics Data System (ADS)

Over Earth history, organisms have developed the ability to control the nucleation and growth of a broad range of nanocrystalline and amorphous materials. The formation of amorphous biosilica is of particular interest because silicifiers sequester gigatons of silica annually, and suppress dissolved silica levels in the ocean to current low levels. The ecological success of marine diatoms, which are arguably the most important silicifiers, places them alongside marine calcifiers as major players in the sequestration of organic carbon. Thus, the biologically mediated formation of amorphous silica plays a key role in the global cycling of silicon and carbon. During controlled biomineralization, nucleation typically occurs in designated locations. There is a substantial body of evidence suggesting that macromolecules in the cellular environment determine these locations by acting as templates to provide energetically favorable sites for the onset of mineral and amorphous material nucleation. In diatoms, silica formation is likely initiated through heterogeneous nucleation on functional portions of macromolecules inside the Silica Deposition Vesicle (SDV). Previous studies of silica nucleation have implicated multiple chemical moieties associated with the constituent amino acids and sugars of polysaccharides, proteins, and glycoproteins as probable sites for in vivo surface nucleation and patterning. These investigations have usually employed complex macromolecules that exhibit multiple functionalities, and un-characterized solution compositions, thus rendering a quantitative analysis of kinetic and thermodynamic processes impossible. The objective of this research is to experimentally test kinetic and thermodynamic controls exercised by surface moieties on silica nucleation. Our experimental model system uses synthetic organic substrates designed to mimic key features of the interfacial regions between the surrounding cellular environment and the amorphous silica surface. While controlling solution chemistry, we can make in situ measurements of nucleation and early stage growth at these interfaces with Atomic Force Microscopy (AFM). Preliminary experiments show that at pH 4 to 7, and supersaturations of 0.76 to 1.45 (? = ln([H4SiO4]/Ksp)), silica nucleates on carboxyl-terminated areas of the surface, that are less than 30 nm in diameter. The nuclei evolve during early stages of growth to spread over the surface into a sheet like form.

Wallace, A. F.; Dove, P. M.

2005-12-01

125

An Observational Study of Early Heterosexual Interaction at Middle School Dances  

ERIC Educational Resources Information Center

In this longitudinal, observational study of heterosexual interaction at middle school dances we examined the degree to which boys' and girls' groups became more gender integrated over time. The results show groups became more integrated over time with the pattern differing by gender. Boys had a relatively low level of contact with girls over the…

Pellegrini, Anthony D.; Long, Jeffery D.

2007-01-01

126

Very Early Ultraviolet and Optical Observations of the Type Ia Supernova 2009ig  

Microsoft Academic Search

Supernova (SN) 2009ig was discovered 17 hr after explosion by the Lick Observatory Supernova Search, promptly classified as a normal Type Ia SN (SN Ia), peaked at V = 13.5 mag, and was equatorial, making it one of the foremost SNe for intensive study in the last decade. Here, we present ultraviolet (UV) and optical observations of SN 2009ig, starting

Ryan J. Foley; P. J. Challis; A. V. Filippenko; M. Ganeshalingam; W. Landsman; W. Li; G. H. Marion; J. M. Silverman; R. L. Beaton; V. N. Bennert; S. B. Cenko; M. Childress; P. Guhathakurta; L. Jiang; J. S. Kalirai; R. P. Kirshner; A. Stockton; E. J. Tollerud; J. Vinkó; J. C. Wheeler; J.-H. Woo

2012-01-01

127

In situ observations of nanoparticle early development kinetics at mineral-water interfaces.  

SciTech Connect

The early development of nanoparticles at mineral?water interfaces exerts crucial influences on the sequestration and transport of aqueous toxic species originating from both natural and anthropogenic sources. Homogeneous and heterogeneous nucleation often occur simultaneously, making it difficult to sort out whether toxic species are transported as free species, sorbed on nanoparticle surfaces, or trapped between aggregated nanoparticles. Here, using a newly developed X-ray scattering setup, we show how homogeneous nucleation and growth can be quantitatively separated from heterogeneous processes under aqueous conditions in real-time. Under conditions found in acid-mine-drainage (at pH 3.6 and [Fe{sup 3+}] = 10{sup -4} M), heterogeneous nucleation of iron oxide nanoparticles on quartz dominated homogeneous nucleation by a factor of 192 (by particle volume). The smallest heterogeneously formed nanoparticles had radii of 1.7 {+-} 0.5 nm, significantly smaller than the size estimated using classical nucleation theory (CNT). Based on the data, the dominant nucleation and growth mechanisms of iron oxide nanoparticles depending on ionic strength were presented. Our findings have implications for the formation and transport of nanoparticles, and thus toxins, in both environmental and biological systems.

Jun, Y. S.; Lee, B.; Waychunas, G. A. (X-Ray Science Division); (Washington Univ.); (LBNL)

2010-10-08

128

Integrating observation and statistical forecasts over sub-Saharan Africa to support Famine Early Warning  

USGS Publications Warehouse

Famine early warning in Africa presents unique challenges and rewards. Hydrologic extremes must be tracked and anticipated over complex and changing climate regimes. The successful anticipation and interpretation of hydrologic shocks can initiate effective government response, saving lives and softening the impacts of droughts and floods. While both monitoring and forecast technologies continue to advance, discontinuities between monitoring and forecast systems inhibit effective decision making. Monitoring systems typically rely on high resolution satellite remote-sensed normalized difference vegetation index (NDVI) and rainfall imagery. Forecast systems provide information on a variety of scales and formats. Non-meteorologists are often unable or unwilling to connect the dots between these disparate sources of information. To mitigate these problem researchers at UCSB's Climate Hazard Group, NASA GIMMS and USGS/EROS are implementing a NASA-funded integrated decision support system that combines the monitoring of precipitation and NDVI with statistical one-to-three month forecasts. We present the monitoring/forecast system, assess its accuracy, and demonstrate its application in food insecure sub-Saharan Africa.

Funk, C.; Verdin, J. P.; Husak, G.

2007-01-01

129

Observations of the Early Evening Boundary-Layer Transition Using a Small Unmanned Aerial System  

NASA Astrophysics Data System (ADS)

The evolution of the lower portion of the planetary boundary layer is investigated using the Small Multifunction Research and Teaching Sonde (SMARTSonde), an unmanned aerial vehicle developed at the University of Oklahoma. The study focuses on the lowest 200 m of the atmosphere, where the most noticeable thermodynamic changes occur during the day. Between October 2010 and February 2011, a series of flights was conducted during the evening hours on several days to examine the vertical structure of the lower boundary layer. Data from a nearby Oklahoma Mesonet tower was used to supplement the vertical profiles of temperature, humidity, and pressure, which were collected approximately every 30 min, starting 2 h before sunset and continuing until dusk. From the profiles, sensible and latent heat fluxes were estimated. These fluxes were used to diagnose the portion of the boundary layer that was most affected by the early evening transition. During the transition period, a shallow cool and moist layer near the ground was formed, and as the evening progressed the cooling affected an increasingly shallower layer just above the surface.

Bonin, Timothy; Chilson, Phillip; Zielke, Brett; Fedorovich, Evgeni

2013-01-01

130

Hereditary distal myopathy with onset in early infancy. Observation of a family.  

PubMed

The study of a family affected with hereditary distal myopathy with onset in early infancy is presented. Complete neurological examination was necessary in several members of the two last generations to discover the existence of the abnormalities of which they were unaware. The propositus was the most affected member of the family iwth distal paresis of the upper and lower extremities and selective paresis of the deltoid muscles. In addition he had kyphoscoliosis, talipes valgus and limitation of mobility of several joints. The onset of the disease was estimated as before the age of 2 when the child started walking. There was no progression of the disease. Clinical examination suggested a myopathic origin of the condition. A sural nerve biopsy was normal. Light-microscopy histochemical studies disclosed a predominance of type I fibres which were at the same time hypotrophic. Subsarcolemmal deposits of mitochondria were present although they were scanty and of normal ultrastructural appearance. In view of the morphological presentation it is postulated that this disease should be classified within the groups of myopathies accompanied by disproportion of fibres and selective atrophy of type I fibres. PMID:681974

Bautista, J; Rafel, E; Castilla, J M; Alberca, R

1978-07-01

131

[Early observations of pancreatic ultrastructure during hemorrhagic necrosis in the rat with closed duodenal pouch].  

PubMed

Many problems are still unanswered in the pathogenesis of acute clinical and experimental pancreatic necrosis. A new technique which can be performed in the rat seems a suitable model for reflux pancreatic necrosis without artificial pressure changes in the ductal system. A closed duodenal loop is obtained with ligation proximal and distal to Vater's ampulla and a gastroenteroanastomosis is associated to avoid intestinal obstruction. All the rats die with hemorrhagic pancreatic necrosis in 36 hours. After 12 hours from the operation ductal and acinar lumina are enlarged. In the centroacinar and intercalated duct cells some lysosomes and mitochondria with clear matrix and reduced cristae are detected. Intercellular junctions in ducts and acini have normal morphology. In the basal cytoplasm of acinar cells some prominent autophagic vacuoles are detectable. After 24 hours in the acinar cells autophagic vacuoles are greatly increased and basal cytoplasmic degeneration often occurs, with plasmalemma and basal lamina interruptions. Intercellular junctions are apparently unaffected until cell necrosis sets in. In blood capillaries endothelial cells are swollen, fibrin thrombosis, hemorrhage and leucocyte infiltration are often detectable. As lysosomal activity occurs also in different kinds of experimental pancreatic necrosis, it could be a common pathogenetic factor, responsible for hydrolytic enzyme activation and for vascular damage in the early stages of hemorrhagic pancreatic necrosis. PMID:317944

Romagnoli, P; Bandettini, L; Cardini, S; Brugnola, D

1979-02-15

132

Early Fermi Gamma-ray Space Telescope Observations of the Quasar 3C 454.3  

Microsoft Academic Search

This is the first report of Fermi Gamma-Ray Space Telescope observations of the quasar 3C 454.3, which has been undergoing pronounced long-term outbursts since 2000. The data from the Large Area Telescope, covering 2008 July 7-October 6, indicate strong, highly variable gamma-ray emission with an average flux of ~3 × 10-6 photons cm-2 s-1, for energies >100 MeV. The gamma-ray

A. A. Abdo; M. Ackermann; M. Ajello; W. B. Atwood; M. Axelsson; L. Baldini; J. Ballet; G. Barbiellini; D. Bastieri; M. Battelino; B. M. Baughman; K. Bechtol; R. Bellazzini; B. Berenji; R. D. Blandford; E. D. Bloom; E. Bonamente; A. W. Borgland; A. Bouvier; J. Bregeon; A. Brez; M. Brigida; P. Bruel; T. H. Burnett; G. A. Caliandro; R. A. Cameron; P. A. Caraveo; J. M. Casandjian; E. Cavazzuti; C. Cecchi; E. Charles; S. Chaty; A. Chekhtman; C. C. Cheung; J. Chiang; S. Ciprini; R. Claus; J. Cohen-Tanugi; L. R. Cominsky; J. Conrad; L. Costamante; S. Cutini; C. D. Dermer; A. de Angelis; F. de Palma; S. W. Digel; E. do Couto e. Silva; D. Donato; P. S. Drell; R. Dubois; D. Dumora; C. Farnier; C. Favuzzi; W. B. Focke; L. Foschini; M. Frailis; L. Fuhrmann; Y. Fukazawa; S. Funk; P. Fusco; F. Gargano; D. Gasparrini; N. Gehrels; S. Germani; B. Giebels; N. Giglietto; P. Giommi; F. Giordano; T. Glanzman; G. Godfrey; I. A. Grenier; M.-H. Grondin; J. E. Grove; L. Guillemot; S. Guiriec; Y. Hanabata; A. K. Harding; R. C. Hartman; M. Hayashida; E. Hays; R. E. Hughes; G. Jóhannesson; A. S. Johnson; R. P. Johnson; W. N. Johnson; T. Kamae; H. Katagiri; J. Kataoka; N. Kawai; M. Kerr; J. Knödlseder; M. L. Kocian; F. Kuehn; M. Kuss; L. Latronico; S.-H. Lee; M. Lemoine-Goumard; F. Longo; F. Loparco; B. Lott; M. N. Lovellette; P. Lubrano; G. M. Madejski; A. Makeev; E. Massaro; M. N. Mazziotta; J. E. McEnery; S. McGlynn; C. Meurer; P. F. Michelson; W. Mitthumsiri; T. Mizuno; A. A. Moiseev; C. Monte; M. E. Monzani; A. Morselli; I. V. Moskalenko; S. Murgia; P. L. Nolan; J. P. Norris; E. Nuss; T. Ohsugi; N. Omodei; E. Orlando; J. F. Ormes; D. Paneque; J. H. Panetta; D. Parent; V. Pelassa; M. Pepe; M. Pesce-Rollins; F. Piron; T. A. Porter; S. Rainò; R. Rando; M. Razzano; A. Reimer; O. Reimer; T. Reposeur; L. C. Reyes; S. Ritz; L. S. Rochester; A. Y. Rodriguez; F. Rahoui; F. Ryde; H. F.-W. Sadrozinski; R. Sambruna; D. Sanchez; A. Sander; P. M. Saz Parkinson; C. Sgrò; M. S. Shaw; D. A. Smith; P. D. Smith; G. Spandre; P. Spinelli; J.-L. Starck; M. S. Strickman; D. J. Suson; H. Tajima; H. Takahashi; T. Takahashi; T. Tanaka; J. B. Thayer; J. G. Thayer; D. J. Thompson; L. Tibaldo; D. F. Torres; G. Tosti; A. Tramacere; Y. Uchiyama; T. L. Usher; N. Vilchez; M. Villata; V. Vitale; A. P. Waite; B. L. Winer; K. S. Wood; T. Ylinen; J. A. Zensus; M. Ziegler

2009-01-01

133

Early Fermi Gamma-ray Space Telescope Observations of the Quasar 3C454.3  

SciTech Connect

This is the first report of Fermi Gamma-ray Space Telescope observations of the quasar 3C 454.3, which has been undergoing pronounced long-term outbursts since 2000. The data from the Large Area Telescope (LAT), covering 2008 July 7-October 6, indicate strong, highly variable {gamma}-ray emission with an average flux of {approx} 3 x 10{sup -6} photons cm{sup -2} s{sup -1}, for energies > 100 MeV. The {gamma}-ray flux is variable, with strong, distinct, symmetrically-shaped flares for which the flux increases by a factor of several on a time scale of about three days. This variability indicates a compact emission region, and the requirement that the source is optically thin to pair-production implies relativistic beaming with Doppler factor {delta} > 8, consistent with the values inferred from VLBI observations of superluminal expansion ({delta} {approx} 25). The observed {gamma}-ray spectrum is not consistent with a simple power-law, but instead steepens strongly above {approx} 2 GeV, and is well described by a broken power-law with photon indices of {approx} 2.3 and {approx} 3.5 below and above the break, respectively. This is the first direct observation of a break in the spectrum of a high luminosity blazar above 100 MeV, and it is likely direct evidence for an intrinsic break in the energy distribution of the radiating particles. Alternatively, the spectral softening above 2GeV could be due to -ray absorption via photonphoton pair production on the soft X-ray photon field of the host AGN, but such an interpretation would require the dissipation region to be located very close ({approx}< 100 gravitational radii) to the black hole, which would be inconsistent with the X-ray spectrum of the source.

Abdo, A

2009-05-07

134

Recent increases in trifluoromethane (HFC-23) global emissions and early atmospheric changes observed for other hydrofluorocarbons  

NASA Astrophysics Data System (ADS)

Trifluoromethane (HFC-23) is an unintended by-product of chlorodifluoromethane (HCFC-22) production and has a 100-yr global warming potential of 14,800. Firn-air and ambient air measurements of HFC-23 from three firn sampling excursions to Antarctica between 2001 and 2009 are used to construct a consistent atmospheric history for this chemical in the Southern Hemisphere. The results show continued increases in the atmospheric abundance of HFC-23 and imply substantial increases in HFC-23 global emissions since 2003. These emission increases are coincident with rapidly increasing HCFC-22 production in developing countries and are observed despite efforts in recent years to limit emissions of HFC-23 through the Kyoto Protocol’s Clean Development Mechanism. These results will be considered along with new observations of additional HFCs from archived air, firn air, and ongoing flask-air measurements. Considered together, atmospheric increases observed for hydrochlorofluorocarbons and hydrofluorocarbons accounted for ~9% of the increase in total direct radiative forcing from anthropogenic gases during 2003-2008, an addition that was slightly larger than attributable to N2O over this same period.

Montzka, S. A.; Miller, B. R.; Battle, M. O.; Aydin, K. M.; Fahey, D. W.; Hall, B. D.; Miller, L.; Verhulst, K. R.; Saltzman, E.; McFarland, M.

2009-12-01

135

Early stroke care in Italy--a steep way ahead: an observational study  

PubMed Central

Objectives To measure the performance of selected Italian emergency medical system (EMS) dispatch centres managing calls for patients suffering from stroke. Data on outcome and on early treatment in the ED were collected. Methods Prospective data collection for a trimester from interventions for a suspected stroke in 13 EMS dispatch centres over five Italian regions. Results Altogether, 1041 calls for a suspected stroke were analysed. Mean intervals of the sequential phases were 2.3±2 minutes between call and ambulance dispatch, 8.4±5.5 minutes to reach the patient, 14.5±8.5 minutes on the scene, and 40.2±16.2 minutes between call and arrival at the ED. Interventions were performed in 56% of cases by a basic life support (BLS) crew, advanced life support (ALS) crews intervened in 28% of cases, and a combination of ALS and BLS in the remaining 16%. Mean diagnostic interval was 99±85 minutes between emergency system call and the first CT scan. This was performed 71±27 minutes after ED admission. Only 1.6% were admitted to a stroke unit. One month outcome according to GCS was good recovery in 32%, moderate disability in 28%, severe disability in 14%, and death in 25% of the patients. Conclusions Mean times show a rapid response of the selected EMS dispatch centres to calls for a suspected stroke. Nevertheless, mean times of the ED phase are still unacceptable according to international guidelines such as Brain Attack Coalition and American Stroke Association guidelines. Efforts should be spent to reduce the time between the arrival and the CT scan and more patients should be admitted to a stroke unit.

Citerio, G; Galli, D; Pesenti, A

2006-01-01

136

AN OBSERVATIONAL DETERMINATION OF THE PROTON TO ELECTRON MASS RATIO IN THE EARLY UNIVERSE  

SciTech Connect

In an effort to resolve the discrepancy between two measurements of the fundamental constant mu, the proton to electron mass ratio, at early times in the universe we reanalyze the same data used in the earlier studies. Our analysis of the molecular hydrogen absorption lines in archival Very Large Telescope/Ultraviolet and Visible Echelle Spectrometer (UVES) spectra of the damped Lyman alpha systems in the quasi-stellar objects Q0347-383 and Q0405-443 yields a combined measurement of a DELTAmu/mu value of (-7 +- 8) x 10{sup -6}, consistent with no change in the value of mu over a time span of 11.5 Gyr. Here, we define DELTAmu as (mu {sub z} - mu{sub 0}) where mu {sub z} is the value of mu at a redshift of z and mu{sub 0} is the present-day value. Our null result is consistent with the recent measurements of King et al., DELTAmu/mu = (2.6 +- 3.0) x 10{sup -6}, and inconsistent with the positive detection of a change in mu by Reinhold et al. Both of the previous studies and this study are based on the same data but with differing analysis methods. Improvements in the wavelength calibration over the UVES pipeline calibration is a key element in both of the null results. This leads to the conclusion that the fundamental constant mu is unchanged to an accuracy of 10{sup -5} over the last 80% of the age of the universe, well into the matter dominated epoch. This limit provides constraints on models of dark energy that invoke rolling scalar fields and also limits the parameter space of supersymmetric or string theory models of physics. New instruments, both planned and under construction, will provide opportunities to greatly improve the accuracy of these measurements.

Thompson, Rodger I.; Bechtold, Jill; Eisenstein, Daniel; Fan, Xiaohui; Kennicutt, Robert C.; Shirley, Yancey L. [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Black, John H. [Onsala Space Observatory, Chalmers University of Technology, SE-43992 Onsala (Sweden); Martins, Carlos [Centro de AstrofIsica, Universidade do Porto, Rua das Estrelas, 4150-762 Porto (Portugal); Prochaska, J. Xavier, E-mail: rit@email.arizona.ed, E-mail: jbechtold@as.arizona.ed, E-mail: deisenstein@as.arizona.ed, E-mail: fan@as.arizona.ed, E-mail: yshirley@as.arizona.ed, E-mail: John.Black@chalmers.s, E-mail: robk@ast.cam.ac.u, E-mail: C.J.A.P.Martins@damtp.cam.ac.u, E-mail: xavier@ucolick.or [Lick Observatory and University of California Santa Cruz, Santa Cruz, CA 95064 (United States)

2009-10-01

137

A novel system for in-situ observations of early hydration reactions in wet conditions in conventional SEM  

SciTech Connect

A novel system enabling wet microscopy in conventional SEM is described and its performance for in-situ study of hydration reactions is demonstrated. The technology is based on a sealed specimen capsule, which is protected from the microscope vacuum by an electron-transparent partition membrane. Thus, the wet sample can be placed and observed in a 'conventional' SEM without the need for drying or employing environmental SEM. Early hydration reactions of gypsum and cement systems were followed during the first 24 h.

Katz, A. [National Building Research Institute, Faculty of Civil and Environmental Engineering, Technion - Israel Institute of Technology, Haifa (Israel); Bentur, A. [National Building Research Institute, Faculty of Civil and Environmental Engineering, Technion - Israel Institute of Technology, Haifa (Israel)]. E-mail: bentur@tx.technion.ac.il; Kovler, K. [National Building Research Institute, Faculty of Civil and Environmental Engineering, Technion - Israel Institute of Technology, Haifa (Israel)

2007-01-15

138

LOOKING INTO THE FIREBALL: ROTSE-III AND SWIFT OBSERVATIONS OF EARLY GAMMA-RAY BURST AFTERGLOWS  

SciTech Connect

We report on a complete set of early optical afterglows of gamma-ray bursts (GRBs) obtained with the Robotic Optical Transient Search Experiment (ROTSE-III) telescope network from 2005 March through 2007 June. This set is comprised of 12 afterglows with early optical and Swift/X-Ray Telescope observations, with a median ROTSE-III response time of 45 s after the start of {gamma}-ray emission (8 s after the GCN notice time). These afterglows span 4 orders of magnitude in optical luminosity, and the contemporaneous X-ray detections allow multi-wavelength spectral analysis. Excluding X-ray flares, the broadband synchrotron spectra show that the optical and X-ray emission originate in a common region, consistent with predictions of the external forward shock in the fireball model. However, the fireball model is inadequate to predict the temporal decay indices of the early afterglows, even after accounting for possible long-duration continuous energy injection. We find that the optical afterglow is a clean tracer of the forward shock, and we use the peak time of the forward shock to estimate the initial bulk Lorentz factor of the GRB outflow, and find 100 {approx}< {gamma}{sub 0} {approx}< 1000, consistent with expectations.

Rykoff, E. S. [Physics Department, University of California at Santa Barbara, 2233B Broida Hall, Santa Barbara, CA 93106 (United States); Aharonian, F. [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Akerlof, C. W.; Flewelling, H. A.; McKay, T. A. [Department of Physics, University of Michigan, Ann Arbor, MI 48109 (United States); Ashley, M. C. B.; Phillips, A. [School of Physics, Department of Astrophysics and Optics, University of New South Wales, Sydney, NSW 2052 (Australia); Barthelmy, S. D.; Gehrels, N.; Krimm, H. A. [NASA Goddard Space Flight Center, Laboratory for High Energy Astrophysics, Greenbelt, MD 20771 (United States); Goegues, E. [Faculty of Engineering and Sciences, Sabanci University, Orhanli-Tuzla, 34956 Istanbul (Turkey); Guever, T. [Department of Astronomy, University of Arizona, Tucson, AZ 85721 (United States); Kiziloglu, Ue. [Middle East Technical University, 06531 Ankara (Turkey); Oezel, M. [Cag Ueniversitesi, Faculty of Arts and Sciences, Yenice-Tarsus/Mersin (Turkey); Quimby, R. M. [Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Rowell, G. [School of Chemistry and Physics, University of Adelaide, Adelaide 5005 (Australia); Rujopakarn, W. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Schaefer, B. E. [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803 (United States); Smith, D. A. [Guilford College, Greensboro, NC 27410 (United States); Vestrand, W. T. [Los Alamos National Laboratory, NIS-2 MS D436, Los Alamos, NM 87545 (United States)], E-mail: erykoff@physics.ucsb.edu (and others)

2009-09-01

139

Direct Constraints on the Evolution of LMXBs from Deep Chandra and HST Observations of Nearby Early-Type Galaxies  

NASA Astrophysics Data System (ADS)

Studies of X-ray binary populations in galaxies allow us to gain insight into the key factors contributing to the formation and evolution of compact objects, the stars involved in the accreting binary phase, and their associated remnants (e.g., millisecond pulsars and compact-object binaries). Early-type galaxies contain predominantly old stars (3-12 Gyr) and have X-ray emission dominated by low-mass X-ray binary (LMXB) populations. I will present results from deep Chandra and HST observations of three nearby early-type galaxies (NGC 3115, 3379, and 3384) that have luminosity-weighted stellar ages covering the range of ~3-10 Gyr. These data allow for the clean identification of field LMXB populations (i.e., sources not coincident with globular clusters), and provide unique measurements for how the field LMXB X-ray luminosity function evolves with time. Leading X-ray binary population synthesis models predict that field LMXB populations will be more prevalent and luminous in the younger early-type galaxies. For the first time, we can unambiguously confront these models and provide important new insight into the formation and evolution of LMXBs.

Lehmer, Bret; Berkeley, M.; Alexander, D. M.; Basu-Zych, A.; Bauer, F. E.; Brandt, W. N.; Fragos, T.; Hornschemeier, A. E.; Jenkins, L.; Kalogera, V.; Ptak, A.; Sivakoff, G. R.; Tzanavaris, P.; Yukita, M.; Zezas, A.

2014-01-01

140

Early Chromospheric Response During a Solar Microflare Observed with SOHO's CDS and RHESSI  

NASA Technical Reports Server (NTRS)

We observed a solar microflare with RHESSI and SOHO's Coronal Diagnostic Spectrometer (CDS) on 2009 July 5. With CDS we obtained rapid cadence (7 s) stare spectra within a narrow field of view toward the center of AR 11024. The spectra contain emission lines from ions that cover a wide range of temperature, including He I (< 0.025 MK), O V (0.25 MK), Si XII (2 MK), and Fe XIX (8 MK). The start of a precursor burst of He I and O V line emission preceded the steady increase of Fe XIX line emission by about 1 minute, and the emergence of 3-12 keV X-ray emission by about 4 minutes. Thus the onset of the microflare was observed in upper chromospheric (He I) and transition region (O V) line emission before it was detected in high temperature flare plasma emission. Redshifted O V emission during the precursor suggests explosive chromospheric evaporation, but no corresponding blueshifts were found with either Fe XIX (which was very weak) or Si XII. Similarly, in subsequent microflare brightenings the O V and He I intensities increased (between 49 s and almost 2 minutes) before emissions from the hot flare plasma. Although these time differences likely indicate heating by a nonthermal particle beam, the RHESSI spectra provide no additional evidence for such a beam. In intervals lasting up to about 3 minutes during several bursts, the He I and O V emission line profiles showed secondary, highly blueshifted ( approximately 200 km/s) components; during intervals lasting nearly 1 minute the velocities of the primary and secondary components were oppositely directed. Combined with no corresponding blueshifts in either Fe XIX or Si XII, this indicates that explosive chromospheric evaporation occurred predominantly at either comparatively cool temperatures (< 2 MK) or within a hot temperature range to which our observations were not sensitive (e.g., between 2 and 8 MK).

Brosius, Jeffrey W.; Holman, Gordon D.

2010-01-01

141

The early Earth Observing System reference handbook: Earth Science and Applications Division missions, 1990-1997  

NASA Technical Reports Server (NTRS)

Prior to the launch of the Earth Observing System (EOS) series, NASA will launch and operate a wide variety of new earth science satellites and instruments, as well as undertake several efforts collecting and using the data from existing and planned satellites from other agencies and nations. These initiatives will augment the knowledge base gained from ongoing Earth Science and Applications Division (ESAD) programs. This volume describes three sets of ESAD activities -- ongoing exploitation of operational satellite data, research missions with upcoming launches between now and the first launch of EOS, and candidate earth probes.

1990-01-01

142

BIMA Observations of Early Stages of High-Mass Star Formation  

NASA Astrophysics Data System (ADS)

To systematically search for high mass protostars without any free-free emission, meaning that no UC HII has formed yet, we studied 70 candidate sources, selected according to their FIR radiation characteristics and their non-detection in Galaxy wide cm continuum surveys (Ramesh & Sridharan 1997), in the water vapor and ammonia lines with the 100 m and, in case of detections, with the 30 m telescope (Menten et al. 1999; Sridharan et al. 1999). This lead to the detection of several new water masers, ubiquitous outflow activity, and several new hot core sources as evident from bright CH3CN emission. As a follow up we started interferometric observations of selected sources using the BIMA array. Here we present observations of IRAS 18089-1732, a source at a distance of 3.6 kpc with about 4 x 104 solar luminosities derived from the IRAS fluxes. The massive core is seen in 3 mm dust continuum emission and is associated with compact (~ 0.03 pc) and hot (T ~ 100 K) strong line emission of CH3CN suggesting an enhancement and heating of this molecule through very recent evaporation of dust grains by a newly born high mass (proto) star.

Wyrowski, Friedrich; Sridharan, T. K.; Menten, Karl M.; Schilke, Peter

1999-10-01

143

Early observations on an emerging Great Lakes invader Hemimysis anomala in Lake Ontario  

USGS Publications Warehouse

Hemimysis anomala, a Ponto-Caspian littoral mysid, is an emerging Great Lakes invader that was discovered in Lakes Michigan and Ontario in 2006. Similar to the native mysid Mysis diluviana, Hemimysis exhibits a diel vertical migration pattern but generally inhabits shallower and warmer waters than M. diluviana. Because basic information on the distribution, habitat use, and biology of Hemimysis in the Great Lakes is scarce, the potential for food web disruption by Hemimysis cannot easily be predicted. Preliminary observations indicate widespread invasion of Hemimysis in Lake Ontario. In this study, we confirm the presence of Hemimysis at sites spanning the northern and southern shores of Lake Ontario and the presence of the individuals during winter months. In one horizontal tow in November 2007, over 26,000 individuals were collected with a length range of 4.4 to 9.0. mm and an average caloric density of 611. cal/g wet weight. The most effective methods for sampling Hemimysis were horizontal tows with either a zooplankton net in the water column or a benthic sled near the lake bottom. Although more quantitative data on the life history and distribution of this species is necessary, our preliminary observations support the prediction that the potential for Hemimysis to impact the nearshore food web in Lake Ontario appears high.

Walsh, Maureen G.; Lantry, Brian F.; Boscarino, Brent; Bowen, Kelly; Gerlofsma, Jocelyn; Schaner, Ted; Back, Richard; Questel, Jennifer; Smythe, A. Garry; Cap, Roberta; Goehle, Michael; Young, Bryan; Chalupnicki, Marc; Johnson, James H.; McKenna, James E.

2010-01-01

144

Observations of the early stages in the formation of an LBV shell  

NASA Astrophysics Data System (ADS)

Luminous blue variables are massive stars that undergo a series of eruptive events through which they shed their outer layers before becoming Wolf-Rayet stars. During the eruptive events, their winds are denser and expand slower than in the non-eruptive state. In this paper we apply a model for the interaction of the post-eruption fast wind with the slower moving shell of dense material that was ejected during the 1994 eruption of HD 5980, a massive system located in the Small Magellanic Cloud. The model predicts a velocity for the working surface that is consistent with the velocity of insterstellar-like absorption features observed in HST/STIS spectra of 1999 and 2000, leading to the conclusion that we have witnessed for the first time the earliest stages of a circumstellar shell being formed around an LBV.

González, Ricardo F.; Koenigsberger, Gloria

2014-01-01

145

HST WFC3 Early Release Science: Emission-Line Galaxies from IR Grism Observations  

NASA Technical Reports Server (NTRS)

We present grism spectra of emission line galaxies (ELGs) from 0.6-1.6 microns from the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST). These new infrared grism data augment previous optical Advanced Camera for Surveys G800L (0.6-0.95 micron) grism data in GOODS South, extending the wavelength coverage well past the G800L red cutoff. The ERS grism field was observed at a depth of 2 orbits per grism, yielding spectra of hundreds of faint objects, a subset of which are presented here. ELGs are studied via the Ha, [O III ], and [OII] emission lines detected in the redshift ranges 0.2 less than or equal to z less than or equal to 1.6, 1.2 less than or equal to z less than or equal to 2.4 and 2.0 less than or equal to z less than or equal to 3.6 respectively in the G102 (0.8-1.1 microns; R approximately 210) and C141 (1.1-1.6 microns; R approximately 130) grisms. The higher spectral resolution afforded by the WFC3 grisms also reveals emission lines not detectable with the G800L grism (e.g., [S II] and [S III] lines). From these relatively shallow observations, line luminosities, star formation rates, and grism spectroscopic redshifts are determined for a total of 25 ELGs to M(sub AB)(F098M) approximately 25 mag. The faintest source in our sample with a strong but unidentified emission line--is MAB(F098M)=26.9 mag. We also detect the expected trend of lower specific star formation rates for the highest mass galaxies in the sample, indicative of downsizing and discovered previously from large surveys. These results demonstrate the remarkable efficiency and capability of the WFC3 NIR grisms for measuring galaxy properties to faint magnitudes.

Straughn, A. N.; Kuntschner, H.; Kuemmel, M.; Walsh, J. R.; Cohen, S. H.; Gardner, J. P.; Windhorst, R. A.; O'Connell, R. W.; Pirzkal, N.; Meurer, G.; McCarthy, P. J.; Hathi, N. P.; Malhotra, S.; Rhoads, J.; Balick, B.; Bond, H. E.; Calzetti, D.; Disney, M. J.; Dopita, M. A.; Frogel, J. A.; Hall, D. N. B.; Holtzman, J. A.; Kimlbe, R. A.; Trauger, J. T.; Young, E. T.

2010-01-01

146

Earth Observations for Early Detection of Agricultural Drought in Countries at Risk: Contributions of the Famine Early Warning Systems Network (FEWS NET) (Invited)  

NASA Astrophysics Data System (ADS)

The Group on Earth Observations' Global Agricultural Monitoring (GEOGLAM) implementation plan emphasizes the information needs of countries at risk of food insecurity emergencies. Countries in this category are often vulnerable to disruption of agricultural production due to drought, while at the same time they lack well developed networks of in-situ observations to support early drought detection. Consequently, it is vital that Earth observations by satellites supplement those available from surface stations. The USGS, in its role as a FEWS NET implementing partner, has recently developed a number of new applications of satellite observations for this purpose. (1) In partnership with the University of California, Santa Barbara, a 30+ year time series of gridded precipitation estimates (CHIRPS) has been developed by blending NOAA GridSat B1 geostationary thermal infrared imagery with station observations using robust geostatistical methods. The core data set consists of pentadal (5-daily) accumulations from 1981-2013 at 0.05 degree spatial resolution between +/- 50 degrees latitude. Validation has been recently completed, and applications for gridded crop water balance calculations and mapping the Standardized Precipitation Index are in development. (2) Actual evapotranspiration (ETa) estimates using MODIS Land Surface Temperature (LST) data at 1-km have been successfully demonstrated using the operational Simplified Surface Energy Balance model with 8-day composites from the LPDAAC. A new, next-day latency implementation using daily LST swath data from the NASA LANCE server is in development for all the crop growing regions of the world. This ETa processing chain follows in the footsteps of (3) the expedited production of MODIS 250-meter NDVI images every five days at USGS EROS, likewise using LANCE daily swath data as input since 2010. Coverage includes Africa, Central Asia, the Middle East, Central America, and the Caribbean. (4) A surface water point monitoring method for pastoralist areas has been successfully demonstrated. It involves mapping small surface water bodies with ASTER and Landsat imagery, delineating their catchment areas with SRTM elevation data, and maintaining a continuous water balance calculation with satellite rainfall and weather model evaporation estimates to track relative fullness of these ephemeral water bodies. Piloted with NASA funds in partnership with Texas A&M University, the technique is now being implemented across the Sahel. (5) To move beyond monitoring and early warning to disaster risk management, loss exceedence probability functions are being derived for crop production shortfalls in FEWS NET countries. Drought hazard indicators, based on both ETa and crop water balance modeling forced by CHIRPS, have been used to develop regional crop drought risk models. In the case of ETa, the drought risk model provides the basis for index insurance in experiments being conducted in Senegal. A program of training events with GEO partners ensures that the data sets and applications are made available to scientists in FEWS NET countries.

Verdin, J. P.; Rowland, J.; Senay, G. B.; Funk, C. C.; Budde, M. E.; Husak, G. J.; Jayanthi, H.

2013-12-01

147

[CII] At 1 < z < 2: Observing Star Formation in the Early Universe with Zeus (1 and 2)  

NASA Technical Reports Server (NTRS)

We report the detection of the [CII] 158 micron fine structure line from six submillimeter galaxies with redshifts between 1.12 and 1.73. This more than doubles the total number of [CII] 158 micron detections reported from high redshift sources. These observations were made with the Redshift(z) and Early Universe Spectrometer(ZEUS) at the Caltech Submillimeter Observatory on Mauna Kea, Hawaii between December 2006 and March 2009. ZEUS is a background limited submm echelle grating spectrometer (Hailey-Dunsheath 2009). Currently we are constructing ZEUS-2. This new instrument will utilize the same grating but will feature a two dimensional transition-edge sensed bolometer array with SQUID multiplexing readout system enabling simultaneous background limited observations in the 200, 340,450 and 650 micron telluric windows. ZEUS-2 will allow for long slit imaging spectroscopy in nearby galaxies and a [CII] survey from z 0.25 to 2.5.

Ferkinhoff, Carl; Hailey-Dunsheath, S.; Nikola, T.; Oberst, T.; Parshley, S.; Stacey, G.; Benford, D.; staguhn, J.

2010-01-01

148

Passive microwave observations of the Wedell Sea during austral winter and early spring  

NASA Technical Reports Server (NTRS)

The results of multispectral passive microwave observations (6.7 to 90-GHz) are presented from the cruises of the FS Polarstern in the Weddell Sea from July to December 1986. This paper includes primarily the analysis of radiometric observations taken at ice station sites. Averaged emissivity spectra for first-year (FY) ice were relatively constant throughout the experiment and were not statistically different from FY ice signatures in the Arctic. Detailed ice characterization was carried out at each site to compare the microwave signatures of the ice with the physical properties. Absorption optical depths of FY ice were found to be sufficiently high that only the structure in the upper portions of the ice contributed significantly to interstation emissivity variations. The emissivities at 90-GHz, e(90), had the greatest variance. Both e(90) at vertical polarization and GR(sub e)(90, 18.7)(defined as (e(sub V)(90)-e(sub V)(18.7))/e(sub V)(90 + e(sub V)(18.7)) depended on the scattering optical depth which is a function of the snow grain diameter and layer thickness. The variance showed a latitude dependence and is probably due to an increase in the strength of snow metamorphism nearer the northern edge of the ice pack. The contribution of variations of near-surface brine volume to the emissivity was not significant over the range of values encountered at the station sites. Emissivity spectra are presented for a range of thin ice types. Unsupervised principal component analysis produced three significant eigenvectors and showed a separation among four different surface types: open water, thin ice, FY ice, and FY ice with a thick snow cover. A comparison with SMMR satellite data showed that average ice concentrations derived from the ship's ice watch log were consistent with the satellite concentrations. The surface based emissivities for FY ice were also compared with emissivities calculated from scanning multichannel microwave radiometer (SMMR) satellite radiances. Best agreement was found at 6.7 and 10-GHz, while at 18 and 37-GHz, SMMR emissivities were slightly lower than surface based results. For the three lower frequencies agreement was found within a confidence limit of 95% and for 37-GHz within about 90%.

Grenfell, T. C.; Comiso, J. C.; Lange, M. A.; Eicken, H.; Wensnahan, M. R.

1994-01-01

149

GHRS observations and theoretical modeling of early type stars in R136a  

NASA Astrophysics Data System (ADS)

We present the first spectroscopic observations of individual stars in R136a, the most dense part of the starburst cluster 30 Doradus in the LMC. Spectra of two stars are scheduled to be obtained with the GHRS on board the HST: R136a5, the brightest of the complex and R136a2, a Wolf-Rayet star of type WN. The 30 Doradus cluster is the only starburst region in which individual stars can be studied. Therefore, quantitative knowledge of the basic stellar parameters will yield valuable insight into the formation of massive stars in starbursts and into their subsequent evolution. Detailed modeling of the structure of the atmosphere and wind of these stars will also lead to a better understanding of the mechanism(s) that govern their dynamics. We present the first results of our detailed quantitative spectral analysis using state-of-the-art non-LTE model atmospheres for stars with extended and expanding atmospheres. The models are computed using the Improved-Sobolev Approximation wind code (ISA-WIND) of de Koter, Schmutz & Lamers (1993, A&A 277, 561), which has been extended to include C, N and Si. Our model computations are not based on the core-halo approximation, but use a unified treatment of the photosphere and wind. This approach is essential for Wolf-Rayet stars. Our synthetic spectra, dominated by the P Cygni profiles of the UV resonance lines, also account for the numerous weak metal lines of photospheric origin.

de Koter, A.; Heap, S.; Hubeny, I.; Lanz, T.; Hutchings, J.; Lamers, H. J. G. L. M.; Maran, S.; Schmutz, W.

1994-05-01

150

Heat Shock Protein 27 is overexpressed in the skin of bitumen exposed workers. Early observations.  

PubMed

The skin of road pavers is exposed to a large number of compounds such as asphalt, bitumen, amines, polymers, oils, solvents, sand, gravel, crushed rock, mineral wad, ultraviolet light and heat. In order to verify an up-regulation of HSP27, determined by the above mentioned stimuli, we studied, immunohistochemically, the forearm skin of a sample of road pavers occupationally exposed. A total of 25 punch biopsies (3 mm diameters) was obtained from the foream skin of road paver workers (n=16) and a control group (n=5) not exposed. Specimens were sectioned (thickness: 3-4 micron ) and processed for immunohistochemistry. For localization of HSP27, a mouse anti-HSP27 monoclonal antibody was used. In punch biopsies of bitumen exposed workers, HSP27 immunostaining was hemogeneously detected in the whole epidermis including basal cell layer. Immunoreaction products were observed mostly in cytoplasm but also in nuclei. Staining intensity was stronger (grade 3 or 4) than that revealed in normal skin sample. PMID:11519351

Fenga, C; Loreto, C; Caltabiano, C; Germanò, D

2000-01-01

151

The performance of field scientists undertaking observations of early life fossils while in simulated space suit  

NASA Astrophysics Data System (ADS)

We conducted simulated Apollo Extravehicular Activity's (EVA) at the 3.45 Ga Australian 'Pilbara Dawn of life' (Western Australia) trail with field and non-field scientists using the University of North Dakota's NDX-1 pressurizable space suit to overview the effectiveness of scientist astronauts employing their field observation skills while looking for stromatolite fossil evidence. Off-world scientist astronauts will be faced with space suit limitations in vision, human sense perception, mobility, dexterity, the space suit fit, time limitations, and the psychological fear of death from accidents, causing physical fatigue reducing field science performance. Finding evidence of visible biosignatures for past life such as stromatolite fossils, on Mars, is a very significant discovery. Our preliminary overview trials showed that when in simulated EVAs, 25% stromatolite fossil evidence is missed with more incorrect identifications compared to ground truth surveys but providing quality characterization descriptions becomes less affected by simulated EVA limitations as the science importance of the features increases. Field scientists focused more on capturing high value characterization detail from the rock features whereas non-field scientists focused more on finding many features. We identified technologies and training to improve off-world field science performance. The data collected is also useful for NASA's "EVA performance and crew health" research program requirements but further work will be required to confirm the conclusions.

Willson, D.; Rask, J. C.; George, S. C.; de Leon, P.; Bonaccorsi, R.; Blank, J.; Slocombe, J.; Silburn, K.; Steele, H.; Gargarno, M.; McKay, C. P.

2014-01-01

152

Algorithm for singular decomposition  

SciTech Connect

An iterative algorithm for the singular value decomposition (SVD) of a non-zero m x n matrix M is described and illustrated numerically. Derivations of the algorithm and sufficient conditions for convergence are outlined.

Ross, D.C.

1984-01-01

153

Problem Decomposition for Reuse.  

National Technical Information Service (NTIS)

An approach to software development problems is presented, and illustrated by an example. The approach is based on the ideas of problem frames and structuring specifications by views. It is claimed that decomposition obtained by this approach result in a ...

D. Jackson M. Jackson

1995-01-01

154

Early evolution of a stratospheric volcanic eruption cloud as observed with TOMS and AVHRR  

USGS Publications Warehouse

This paper is a detailed study of remote sensing data from the total ozone mapping spectrometer (TOMS) and the advanced very high resolution radiometer (AVHRR) satellite detectors, of the 1982 eruption of El Chicho??n, Mexico. The volcanic cloud/atmosphere interactions in the first four days of this eruption were investigated by combining ultraviolet retrievals to estimate the mass of sulfur dioxide in the volcanic cloud [Krueger et al., 1995] with thermal infrared retrievals of the size, optical depth, and mass of fine-grained (1-10 ??m radius) volcanic ash [Wen and Rose, 1994]. Our study provides the first direct evidence of gravitational separation of ash from a stratospheric, gas-rich, plinian eruption column and documents the marked differences in residence times of volcanic ash and sulfur dioxide in volcanic clouds. The eruption column reached as high as 32 km [Carey and Sigurdsson, 1986] and was injected into an atmosphere with a strong wind shear, which allowed for an observation of the separation of sulfur dioxide and volcanic ash. The upper, more sulfur dioxide-rich part of the cloud was transported to the west in the stratosphere, while the fine-grained ash traveled to the south in the troposphere. The mass of sulfur dioxide released was estimated at 7.1 ?? 109 kg with the mass decreasing by approximately 4% 1 day after the peak. The mass of fine-grained volcanic ash detected was estimated at 6.5 ?? 109 kg, amounting to about 0.7% of the estimated mass of the ash which fell out in the mapped ash blanket close to the volcano. Over the following days, 98% of this remaining fine ash was removed from the volcanic cloud, and the effective radius of ash in the volcanic cloud decreased from about 8 ??m to about 4 ??m. Copyright 1999 by the American Geophysical Union.

Schneider, D. J.; Rose, W. I.; Coke, L. R.; Bluth, G. J. S.; Sprod, I. E.; Krueger, A. J.

1999-01-01

155

Observations and theory of Mg II lines in early type stars. II - Theory and predicted profiles. III - The observations and a comparison with the predictions  

NASA Technical Reports Server (NTRS)

Profiles of the UV Mg II lines in the spectra of early type stars are computed in a grid of model atmospheres with effective temperatures between 8000 and 35,000 K and log g values of 2.5 to 4.0 using the LTE and non-LTE theories of line formation. The theoretical results indicate that the line cores are strengthened by non-LTE effects over the entire temperature range, resonance-line wings are weaker in the cooler models than in the LTE case, and very large deviations from LTE occur in the hot low-gravity models. These predictions are compared with the equivalent widths of the UV Mg II lines in 106 stars and of the visual lines in 48 stars (spectral types O4 to A3). The observed equivalent widths of normal stars in luminosity classes II through V are found to agree with the predictions over the entire range from O8 to A2 if a certain Mg/H abundance is adopted. The line intensities observed in supergiants, Be, Bp, and Ap stars are discussed.

Snijders, M. A. J.; Lamers, H. J. G. L. M.

1975-01-01

156

Group on Earth Observations (GEO) Global Drought Monitor Portal: Adding Capabilities for Forecasting Hydrological Extremes and Early Warning Networking  

NASA Astrophysics Data System (ADS)

The Intergovernmental Panel on Climate Change (IPCC 2007) has suggested the hydrometeorological extremes of both drought and flooding may increase under climate change. Drought zones can grow over large tracts of continental area and are a global-scale phenomenon (Sheffield and Wood 2011). The Group on Earth Observations Global Drought Monitor Portal (GDMP) was established as a demonstration for the 5th Earth Observation Ministerial Summit in Beijing in 2010. The European Drought Observatory, the North American Drought Monitor, the Princeton University experimental African Drought Monitor, and the University College London experimental global drought monitor were made "interoperable" through installation of Open Geospatial Consortium (OGC) Web Mapping Services (WMS) on their respective servers, allowing maps of current drought conditions to be exchanged and assembled into maps of global drought coverage on the NIDIS portal. Partners from the Republic of Argentina, the Commonwealth of Australia, China, Jordan, Brazil, and Uruguay have also joined. The GEO Global Drought Monitoring, Forecasting, and Early Warning effort involves multiple parties and institutions, including the World Meteorological Organization, the World Climate Research Program Drought Interest Group, NASA, and others. The GEO Secretariat held a launch workshop in Geneva on 4-6 May 2010 to initiate drafting the final GEO Work Plan, and, during this meeting, additional capabilities were added to the existing GDMP: 1) drought forecasting was added to drought "current conditions" monitoring, in a partnership with Joint Research Centre (and other partners) aiming at a combined platform for Hydrological Extremes (drought and flooding); 2) extending drought forecasts from the medium-range 15-day window to a 30-day window; this will be tested through pilot projects over Europe and Africa, as part of the Global Water Scarcity Information Service (GLOWASIS)and the Improved Drought Early Warning Forecasting for Africa (DEWFORA) to strengthen preparedness and adaptation; 3) setting up an Early Warning System network for drought ( to be developed through World Meteorological Organization WMO); and 4) adding global remote sensing drought monitoring capabilities (soil moisture anomalies). Flooding represents positive precipitation anomalies, whereas drought represents negative precipitation anomalies. The JRC combined Hydrologic Extremes platform will include multiple models and tools, such as; 1) JRC Global Flood Detection System and Global Flood Early Warning System; 2) the WMO Flash Flood Guidance system; 3) the Dartmouth Flood Observatory; 4) a suite of monitored and forecasted drought and water scarcity indicators through the various drought observatories accessible through the GEO Global Drought Monitor Portal. The GEO Global Drought and Flooding systems represent the "applications-side" of water activities within the GEO Work Plan and are supported by the "Research and Development (R&D) side" of water activities within the new 2012-2015 GEO Work Plan.

Pozzi, W.; de Roo, A.; Vogt, J.; Lawford, R. G.; Pappenberger, F.; Heim, R. R.; Stefanski, R.

2011-12-01

157

Battery Electric Vehicle Driving and Charging Behavior Observed Early in The EV Project  

SciTech Connect

As concern about society's dependence on petroleum-based transportation fuels increases, many see plug-in electric vehicles (PEV) as enablers to diversifying transportation energy sources. These vehicles, which include plug-in hybrid electric vehicles (PHEV), range-extended electric vehicles (EREV), and battery electric vehicles (BEV), draw some or all of their power from electricity stored in batteries, which are charged by the electric grid. In order for PEVs to be accepted by the mass market, electric charging infrastructure must also be deployed. Charging infrastructure must be safe, convenient, and financially sustainable. Additionally, electric utilities must be able to manage PEV charging demand on the electric grid. In the Fall of 2009, a large scale PEV infrastructure demonstration was launched to deploy an unprecedented number of PEVs and charging infrastructure. This demonstration, called The EV Project, is led by Electric Transportation Engineering Corporation (eTec) and funded by the U.S. Department of Energy. eTec is partnering with Nissan North America to deploy up to 4,700 Nissan Leaf BEVs and 11,210 charging units in five market areas in Arizona, California, Oregon, Tennessee, and Washington. With the assistance of the Idaho National Laboratory, eTec will collect and analyze data to characterize vehicle consumer driving and charging behavior, evaluate the effectiveness of charging infrastructure, and understand the impact of PEV charging on the electric grid. Trials of various revenue systems for commercial and public charging infrastructure will also be conducted. The ultimate goal of The EV Project is to capture lessons learned to enable the mass deployment of PEVs. This paper is the first in a series of papers documenting the progress and findings of The EV Project. This paper describes key research objectives of The EV Project and establishes the project background, including lessons learned from previous infrastructure deployment and PEV demonstrations. One such previous study was a PHEV demonstration conducted by the U.S. Department of Energy's Advanced Vehicle Testing Activity (AVTA), led by the Idaho National Laboratory (INL). AVTA's PHEV demonstration involved over 250 vehicles in the United States, Canada, and Finland. This paper summarizes driving and charging behavior observed in that demonstration, including the distribution of distance driven between charging events, charging frequency, and resulting proportion of operation charge depleting mode. Charging demand relative to time of day and day of the week will also be shown. Conclusions from the PHEV demonstration will be given which highlight the need for expanded analysis in The EV Project. For example, the AVTA PHEV demonstration showed that in the absence of controlled charging by the vehicle owner or electric utility, the majority of vehicles were charged in the evening hours, coincident with typical utility peak demand. Given this baseline, The EV Project will demonstrate the effects of consumer charge control and grid-side charge management on electricity demand. This paper will outline further analyses which will be performed by eTec and INL to documenting driving and charging behavior of vehicles operated in a infrastructure-rich environment.

John Smart; Stephen Schey

2012-04-01

158

Quality versus Quantity: The Use of Observation by Early Childhood Educators in Improving the Performance of Children Enrolled in Preschool Programs in Ghana  

ERIC Educational Resources Information Center

In the current study, the authors explored how early childhood educators used observation to support children in the learning environment. The objectives set were to find out the observation methods teachers used, ascertain their understanding of child observation, find out activities children undertook, and how teachers documented what children…

Tackie-Ofosu, Vivian; Bentum, Kwesi

2013-01-01

159

Surface decomposition accompanying the perception of transparency.  

PubMed

At the retina, each location can have only one value of luminance or color. When transparency is perceived, however, different surface qualities can be redistributed to two or more apparently superimposed layers. The experiments described here explored the characteristics of this surface decomposition. It is shown that the surface decomposition occurs rapidly, it affects even early stages of visual processing, and it involves attributes such as texture and motion as well as color and brightness. In the first experiment, the recognition advantage for transparent overlapping digits demonstrated that the surface decomposition accompanying transparency occurs within 60 ms. In the second, the separation of overlying orthogonal grids due to surface decomposition was found to influence the strength of the McCollough effect, an effect attributed to early cortical processing. Finally, when a transparent surface appears to extend over areas that are physically identical to the background, qualities of the transparent overlay such as texture and motion, as well as color or brightness (e.g., the neon color effect) appear to spread to the illusory overlay. PMID:8347552

Watanabe, T; Cavanagh, P

1993-01-01

160

The Development of Real-time Strong-motion Observation on the Earthquake Early Warning in Taiwan  

NASA Astrophysics Data System (ADS)

For the sake of seismic hazards mitigation, a real-time strong-motion monitoring system was implemented by the Central Weather Bureau (CWB) since 1995. After successive refinements during the past decade, the system has been utilized as the basis for the development of the early warning (EWS) application in Taiwan. In order to shorten the earthquake response time, a virtual sub-network approach is utilized at first. Under the practical experiment since 2001, for monitoring inland or near offshore earthquakes with magnitude greater than 4.5, the response time can be shorten as 18.8+-3.8 sec averagely. Therefore, it can provide early warning before S-wave arrival for metropolitan areas located 60 km away from the epicenter. For the sake of further reducing the area of so-called blind-zone which cannot provide early warning, we also attempted to utilize vertical displacement records of P-wave as a basis to issue warnings. As results, we found that the amplitude 0.1 cm can be used as a criterion to judge if an earthquake above magnitude 6.0 is occurring in Taiwan Island. Furthermore, we also derived a set of frequency-based formulas simultaneously, which can be used to estimate earthquake magnitude rapidly. To combine the research results, and under the framework of real-time strong-motion observational network, we designed an earthquake early warning algorithm which is suitable for Taiwan Island. According to the experiment on 7 magnitude-above-6.0 earthquakes took place after 2002, the averaged response times is within 15 sec. Furthermore, the processing time for inland earthquakes can be shorten beneath 10 sec, and the radius of blind-zone is reduced to 30 km. Since 2003, the CWB has been replacing the existing 16-bit digital accelero- graphs used in its real-time strong-motion monitoring to 24-bit instruments at an annual replacement rate of 5 to 10% of the total. Besides, some high quality borehole seismic stations and a cable-based Ocean Bottom Seismographic (OBS) system are planed to implement on and off north-eastern Taiwan since 2007. We will further develop the EWS in response to these new instruments, as well as to any new research ideas.

Hsiao, N.; Shin, T.; Wu, Y.

2007-12-01

161

Observation of early shell-dopant mix in OMEGA direct-drive implosions and comparisons with radiation-hydrodynamic simulations  

NASA Astrophysics Data System (ADS)

Temporally, spatially, and spectrally resolved x-ray image data from direct-drive implosions on OMEGA were interpreted with the aid of radiation-hydrodynamic simulations. Neither clean calculations nor those using a turbulent mix model can explain fully the observed migration of shell-dopant material (titanium) into the core. Shell-dopant migration was observed via time-dependent, spatially integrated spectra, and spatially and spectrally resolved x-ray images of capsule implosions and resultant dopant emissions. The titanium emission was centrally peaked in narrowband x-ray images. In post-processed clean simulations, the peak titanium emission forms in a ring in self-emission images as the capsule implodes. Post-processed simulations with mix reproduce trends in time-dependent, spatially integrated spectra, as well having centrally peaked Ti emission in synthetic multiple monochromatic imager. However, mix simulations still do not transport Ti to the core as is observed in the experiment. This suggests that phenomena in addition to the turbulent mix must be responsible for the transport of Ti. Simple diffusion estimates are unable to explain the early Ti mix into the core. Mechanisms suggested for further study are capsule surface roughness, illumination non-uniformity, and shock entrainment.

Baumgaertel, J. A.; Bradley, P. A.; Hsu, S. C.; Cobble, J. A.; Hakel, P.; Tregillis, I. L.; Krasheninnikova, N. S.; Murphy, T. J.; Schmitt, M. J.; Shah, R. C.; Obrey, K. D.; Batha, S.; Johns, H.; Joshi, T.; Mayes, D.; Mancini, R. C.; Nagayama, T.

2014-05-01

162

Purely Dry Mergers do not Explain the Observed Evolution of Massive Early-type Galaxies since z ~ 1  

NASA Astrophysics Data System (ADS)

Several studies have suggested that the observed size evolution of massive early-type galaxies (ETGs) can be explained as a combination of dry mergers and progenitor bias, at least since z ~ 1. In this paper we carry out a new test of the dry-merger scenario based on recent lensing measurements of the evolution of the mass density profile of ETGs. We construct a theoretical model for the joint evolution of the size and mass density profile slope ?' driven by dry mergers occurring at rates given by cosmological simulations. Such dry-merger model predicts a strong decrease of ?' with cosmic time, inconsistent with the almost constant ?' inferred from observations in the redshift range 0 < z < 1. We then show with a simple toy model that a modest amount of cold gas in the mergers—consistent with the upper limits on recent star formation in ETGs—is sufficient to reconcile the model with measurements of ?'. By fitting for the amount of gas accreted during mergers, we find that models with dissipation are consistent with observations of the evolution in both size and density slope, if ~4% of the total final stellar mass arises from the gas accreted since z ~ 1. Purely dry merger models are ruled out at >99% CL. We thus suggest a scenario where the outer regions of massive ETGs grow by accretion of stars and dark matter, while small amounts of dissipation and nuclear star formation conspire to keep the mass density profile constant and approximately isothermal.

Sonnenfeld, Alessandro; Nipoti, Carlo; Treu, Tommaso

2014-05-01

163

Observations of Middle Atmosphere CO from the UARS ISAMS during the Early Northern Winter 1991/92  

NASA Technical Reports Server (NTRS)

Structure and kinematics of carbon monoxide in the upper stratosphere and lower mesosphere (10-0.03 hPa) are studied for the early northern winter 1991/92 using the Upper Atmosphere Research Satellite Improved Stratospheric and Mesospheric Sounder (ISAMS) measurements. The study is aided by data from a 6-week parameterized-chemistry run of the Goddard Space Flight Center 3D Chemistry and Transport Model (CTM), initialized on 8 December 1991. Generally, CO mixing ratios increase with height due to the increasing source contribution from CO, photolysis. In the tropical upper stratosphere. however, a local maximum in CO mixing ratio occurs. A simple photochemical model is used to show that this feature results largely from methane oxidation. In the extratropics the photochemical lifetime of CO is long, and therefore its evolution is dictated by large-scale motion of air. evidenced by strong correlation with Ertel potential vorticity. This makes CO one of the few useful observable tracers at the stratopause level and above. Thus CO maps are used to study the synoptic evolution of the polar vortex in early January 1992. Modified Lagrangian mean mixing diagnostics are applied to ISAMS and CTM data to examine the strength of the mixing barrier at the polar vortex edge. It is demonstrated that planetary wave activity weakens the barrier. promoting vortex erosion. The vortex erosion first appears in the lower mesosphere and subsequently descends through the upper stratosphere. and is attributed to effects of planetary wave dissipation. Agreement between ISAMS and CTM is good in the horizontal distribution of CO throughout the examined period, but vertical CO gradients in the CTM weaken with time relative to the ISAMS observations.

Allen, D. R.; Stanford, J. L.; Lopez-Valverde, M. A.; Nakamura, N.; Lary, D. J.; Douglass, A. R.; Cerniglia, M. C.; Remedios, J. J.; Taylor, F. W.

1999-01-01

164

The VLA Low Band Project: Early Commissioning Results and Vision for a Primary Focus-based Commensal Observing system  

NASA Astrophysics Data System (ADS)

We present an update on the Jansky Very Large Array Low Band (VLA-LB) project, currently undergoing scientific commissioning and expected to be fully available in 2013. VLA-LB is a joint NRL and NRAO initiative to equip the VLA with broadband low frequency receivers that cover the spectrum between 66 and 470 MHz. The current system can already access the 66 to 86 MHz and 230 to 436 MHz sub-bands by working with existing 74 and 330 MHz feeds, respectively. The bandwidth at 74 MHz will increase by more than an order of magnitude while the 330 MHz bandwidth increases by approximately a factor of 6. The improved bandwidth and system temperature, coupled with the power of the WIDAR correlator, promise significantly enhanced performance compared to past VLA capabilities. Early commissioning results at “P band” (330 MHz) with a handful of antennas accessing the larger bandwidth indicate sensitivity rivaling that of the legacy 27-antenna, narrow-band old VLA capability. New feeds that can exploit a larger fraction of the available receiver bandwidth are being explored. While VLA-LB is useful as a conventional system, we are looking to enhance its power by leveraging the VLA’s capability to detect radiation at its prime and Cassegrain foci simultaneously. The ability to observe with more than one band in parallel is a powerful multiplier of a telescope’s function, and many instruments (e.g. the GMRT, WSRT and VLA) offer this. A variant is being explored for VLA-LB: observing from the prime focus during all normal Cassegrain observations. This proposed VLA-LB commensal system would piggyback normal VLA observing time to survey at low frequencies with relatively large field of views. Shared fields with other multi-beaming, dipole-based arrays that view the same sky with the VLA, e.g. the first station of the Long Wavelength Array (LWA1), would be possible. The collected data will be assembled into a database of spectra and wide-field images, suitable for studies of individual objects as well as searches for transients and high redshift spectral features (eg. HI absorption or OH mega-masers). We describe how the VLA-LB commensal system might be implemented, and explore early ideas for its scientific promise.

Kassim, Namir E.; Clarke, T. E.; Hicks, B.; Peters, W. M.; Wilson, T. L.; Cutchin, S.; Owen, F. N.; Perley, R. A.; Durand, S.; Kutz, C.; Harden, P.; Intema, H.; Brisken, W.; Subrahmanyan, R.; Taylor, G. B.; Lazio, T. J.

2013-01-01

165

The generalized triangular decomposition  

NASA Astrophysics Data System (ADS)

Given a complex matrix mathbf{H} , we consider the decomposition mathbf{H} = mathbf{QRP}^* , where mathbf{R} is upper triangular and mathbf{Q} and mathbf{P} have orthonormal columns. Special instances of this decomposition include the singular value decomposition (SVD) and the Schur decomposition where mathbf{R} is an upper triangular matrix with the eigenvalues of mathbf{H} on the diagonal. We show that any diagonal for mathbf{R} can be achieved that satisfies Weyl's multiplicative majorization conditions: prod_{iD1}^k \\vert r_{i}\\vert le prod_{iD1}^k sigma_i, ; ; 1 le k < K, quad prod_{iD1}^K \\vert r_{i}\\vert = prod_{iD1}^K sigma_i, where K is the rank of mathbf{H} , sigma_i is the i -th largest singular value of mathbf{H} , and r_{i} is the i -th largest (in magnitude) diagonal element of mathbf{R} . Given a vector mathbf{r} which satisfies Weyl's conditions, we call the decomposition mathbf{H} = mathbf{QRP}^* , where mathbf{R} is upper triangular with prescribed diagonal mathbf{r} , the generalized triangular decomposition (GTD). A direct (nonrecursive) algorithm is developed for computing the GTD. This algorithm starts with the SVD and applies a series of permutations and Givens rotations to obtain the GTD. The numerical stability of the GTD update step is established. The GTD can be used to optimize the power utilization of a communication channel, while taking into account quality of service requirements for subchannels. Another application of the GTD is to inverse eigenvalue problems where the goal is to construct matrices with prescribed eigenvalues and singular values.

Jiang, Yi; Hager, William W.; Li, Jian

2008-06-01

166

Unusually strong nitric oxide descent in the Arctic middle atmosphere in early 2013 as observed by Odin/SMR  

NASA Astrophysics Data System (ADS)

The middle atmosphere has been affected by an exceptionally strong midwinter stratospheric sudden warming (SSW) during the Arctic winter 2012/2013. These unusual meteorological conditions led to a breakdown of the polar vortex, followed by the reformation of a strong upper stratospheric vortex associated with particularly efficient descent of air. Measurements by the Sub-Millimetre Radiometer (SMR), on board the Odin satellite, show that very large amounts of nitric oxide (NO), produced by Energetic Particle Precipitation (EPP) in the mesosphere/lower thermosphere (MLT), could thus enter the polar stratosphere in early 2013. The mechanism referring to the downward transport of EPP generated-NOx during winter is generally called the EPP indirect effect. SMR observed up to 20 times more NO in the upper stratosphere than the average NO measured at the same latitude, pressure and time during three previous winters where no mixing between mesospheric and stratospheric air was noticeable. This event turned out to be an unprecedently strong case of this effect. Our study is based on a comparison with the Arctic winter 2008/2009, when a similar situation was observed and which was so far considered as a record-breaking winter for this kind of events. This outstanding situation is the result of the combination between a relatively high geomagnetic activity and an unusually high dynamical activity, which makes this case a prime example to study the EPP impacts on the atmospheric composition.

Pérot, K.; Urban, J.; Murtagh, D. P.

2014-02-01

167

BOLOCAM OBSERVATIONS OF TWO UNCONFIRMED GALAXY CLUSTER CANDIDATES FROM THE PLANCK EARLY SUNYAEV-ZEL'DOVICH SAMPLE  

SciTech Connect

We present Bolocam observations of two galaxy cluster candidates reported as unconfirmed in the Planck early Sunyaev-Zel'dovich (eSZ) sample, PLCKESZ G115.71+17.52 and PLCKESZ G189.84-37.24. We observed each of these candidates with Bolocam at 140 GHz from the Caltech Submillimeter Observatory in 2011 October. The resulting images have white noise levels of {approx_equal} 30 {mu}K{sub CMB} arcmin in their central regions. We find a significant SZ decrement toward PLCKESZ G115.71. This decrement has a false detection probability of 5.3 Multiplication-Sign 10{sup -5}, and we therefore confirm PLCKESZ G115.71 as a cluster. The maximum SZ decrement toward PLCKESZ G189.84 corresponds to a false detection probability of 0.027, and it therefore remains as an unconfirmed cluster candidate. In order to make our SZ-derived results more robust, we have also analyzed data from the Wide-field Infrared Survey Explorer (WISE) at the location of each cluster candidate. We find an overdensity of WISE sources consistent with other clusters in the eSZ at the location of PLCKESZ G115.71, providing further evidence that it is a cluster. We do not find a significant overdensity of WISE sources at the location of PLCKESZ G189.84.

Sayers, J.; Czakon, N. G.; Bridge, C.; Golwala, S. R. [Division of Physics, Math, and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Koch, P. M.; Lin, K.-Y.; Umetsu, K. [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China); Molnar, S. M., E-mail: jack@caltech.edu [LeCosPA Center, National Taiwan University, Taipei 10617, Taiwan (China)

2012-04-10

168

Biological characterization and selection criteria of adjuvant chemotherapy for early breast cancer: experience from the Italian observational NEMESI study  

PubMed Central

Background International treatment guidelines recommend administration of adjuvant chemotherapy in early breast cancer based on clinical, prognostic and predictive parameters. Methods An observational study (NEMESI) was conducted in 63 Italian oncology centres in patients with early breast cancer. Age, performance status, concomitant disease, menopausal status, histology, tumor dimension (pT), axillary lymph node status (pN), grading (G), estrogen and progesterone receptor (ER and PgR), proliferative index (ki67 or MIB-1), human epidermal growth factor receptor 2 (HER2) and type of adjuvant treatment were recorded. The primary objective of the study was to define parameters influencing the decision to prescribe adjuvant chemotherapy and the type of chemotherapy. Results Data for 1894 patients were available. 69.0% postmenopausal, 67.0% pT1, 22.3% pTmic/pT1a/pT1b, 61.0% pN0, 48.7% luminal A, 18.1% luminal B, 16.1% HER2 positive, 8.7% triple negative, 8.4% unknown. 57.8% received adjuvant chemotherapy: 38.1% of luminal A, 67.3% luminal B, 88.2% HER2-positive, 97.6% triple negative. Regimens administered: 9.1% CMF-like, 48.8% anthracyclines, 38.4% anthracyclines plus taxanes, 3.7% taxanes alone. Increasing pT/pN and, marginally, HER2-positive were associated with the prescription of anthracyclines plus taxanes. Suboptimal schedules (CMF-like or AC/EC or FEC-75) were prescribed in 37.3% receiving chemotherapy, even in HER2-positive and triple negative disease (36.5% and 34.0%, respectively). Conclusions This study showed an overprescription of adjuvant chemotherapy for early breast cancer, particularly referred to luminal A. pT, pN and, marginally, HER2 were the principal determinants for the choice of chemotherapy type. Suboptimal chemotherapy regimens were adopted in at least one third of HER2-positve and triple negative.

2012-01-01

169

An observational study on early-lactation metabolic profiles in Swedish organically and conventionally managed dairy cows.  

PubMed

The aim of this observational study was to compare indicators of energy balance in early lactation in organically managed dairy cows (OMC) and conventionally managed dairy cows (CMC) under field conditions. The diets of OMC and CMC differ as a consequence of the rules and principles of organic dairy farming. The study was based on clinical examinations and blood samples from cows within the range from 2 wk prepartum to 6 wk postpartum, collected from 20 organic and 20 conventional dairy farms with 3 visits at each farm. The farms were located in a southeastern area of Sweden and ranged in size from 45 to 120 cows. The blood parameters selected to reflect energy metabolism were nonesterified fatty acids, beta-hydroxybutyrate, glucose, and insulin. At clinical examination body condition score was registered. The shape of the lactation curve in early lactation was modeled to assess potential differences that could explain the blood parameter profiles. The conventionally managed cows increased their milk yield faster than OMC within the first 2 wk of lactation. Blood nonesterified fatty acid concentrations were similar between the management types, but with a tendency of lesser concentrations in OMC, primarily in early lactation. Postcalving beta-hydroxybutyrate concentrations were constantly lesser in OMC during the first 6 wk of lactation. An interaction between season and insulin concentration necessitated stratification on season. During spring the profiles overlapped, but there was a significant difference in the first 4 d post-calving, when organically managed cows had greater insulin concentrations and in d 30 to 34 when conventionally managed cows had greater insulin concentrations. During fall the profiles overlapped completely and there was no significant difference at any point in time. Glucose concentrations tended to decrease slightly postcalving followed by a gradual elevation to a concentration just under the precalving concentration during the study period. Body condition scores decreased slightly over the study period. No differences were found between the management types with regard to glucose concentrations or registered body condition score. In conclusion, the OMC did not show a greater extent of mobilization of body tissue than CMC as expressed by our study variables. Hence, OMC adjusted the production amount according to feed intake. PMID:18832222

Fall, N; Gröhn, Y T; Forslund, K; Essen-Gustafsson, B; Niskanen, R; Emanuelson, U

2008-10-01

170

The Old, the Young, and the Restless: Insights from HST Observations of Early-type Galaxy Evolution at Intermediate Redshift  

NASA Astrophysics Data System (ADS)

We present a catalog of intermediate (0.35early-type galaxies (ETGs) observed with the Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3). We combined WFC3 and archival Advanced Camera for Surveys (ACS) images to produce a panchromatic (0.2observed photometry into the GALEX FUV and NUV and Johnson V bandpasses, and identified a diversity in the rest-frame UV-optical colors of the ETGs indicating that these galaxies are not uniformly "red and dead." We fit two component stellar population spectral templates to the broad-band photometry to better constrain the stellar sources of the UV emission, and measured the relative mass fractions of young (t<1Gyr) and old (t > 4Gyr) stellar populations. This analysis confirmed that the ETGs' blue rest-frame UV-optical colors are due to the presence of young stars associated with relatively low-level recent star formation (RSF). The high spatial resolution of WFC3/ACS enabled us to make a quantitative (e.g., Sersic profile fitting) and qualitative assessment of each ETG and its local environment in order to identify morphological signatures of the physical mechanism(s) driving this RSF. From this analysis, we conclude that RSF in these ETGs is not driven by a single, dominant process. Instead, RSF is motivated by secular and minor (but not major) merger processes. These results are in general agreement with observations of ETGs at both the local (z<0.1) and high (z>1.5) redshift universe.

Rutkowski, Michael J.

2013-01-01

171

Identification of old tidal dwarfs near early-type galaxies from deep imaging and H I observations  

NASA Astrophysics Data System (ADS)

It has recently been proposed that the dwarf spheroidal galaxies located in the Local Group discs of satellites (DoSs) may be tidal dwarf galaxies (TDGs) born in a major merger at least 5 Gyr ago. Whether TDGs can live that long is still poorly constrained by observations. As part of deep optical and H I surveys with the Canada-France-Hawaii Telescope (CFHT) MegaCam camera and Westerbork Synthesis Radio Telescope made within the ATLAS3D project, and follow-up spectroscopic observations with the Gemini-North telescope, we have discovered old TDG candidates around several early-type galaxies. At least one of them has an oxygen abundance close to solar, as expected for a tidal origin. This confirmed pre-enriched object is located within the gigantic, but very low surface brightness, tidal tail that emanates from the elliptical galaxy, NGC 5557. An age of 4 Gyr estimated from its SED fitting makes it the oldest securely identified TDG ever found so far. We investigated the structural and gaseous properties of the TDG and of a companion located in the same collisional debris, and thus most likely of tidal origin as well. Despite several Gyr of evolution close to their parent galaxies, they kept a large gas reservoir. Their central surface brightness is low and their effective radius much larger than that of typical dwarf galaxies of the same mass. This possibly provides us with criteria to identify tidal objects which can be more easily checked than the traditional ones requiring deep spectroscopic observations. In view of the above, we discuss the survival time of TDGs and question the tidal origin of the DoSs.

Duc, Pierre-Alain; Paudel, Sanjaya; McDermid, Richard M.; Cuillandre, Jean-Charles; Serra, Paolo; Bournaud, Frédéric; Cappellari, Michele; Emsellem, Eric

2014-05-01

172

The decomposition of methyltrichlorosilane: Studies in a high-temperature flow reactor  

SciTech Connect

Experimental measurements of the decomposition of methyltrichlorosilane (MTS), a common silicon carbide precursor, in a high-temperature flow reactor are presented. The results indicate that methane and hydrogen chloride are major products of the decomposition. No chlorinated silane products were observed. Hydrogen carrier gas was found to increase the rate of MTS decomposition. The observations suggest a radical-chain mechanism for the decomposition. The implications for silicon carbide chemical vapor deposition are discussed.

Allendorf, M.D.; Osterheld, T.H.; Melius, C.F.

1994-01-01

173

Problem Decomposition for Reuse  

Microsoft Academic Search

An approach to software development problems is presented, and illustratedby an example. The approach is based on the ideas of problem frames andstructuring specifications by views. It is claimed that decompositions obtainedby this approach result in a more effective separation of concerns,and that the resulting components are more likely to be reusable than thoseobtained by more conventional approaches. The characteristics

Daniel Jackson; Michael Jackson

1995-01-01

174

DECOMPOSITIONS IN QUANTUM LOGIC  

Microsoft Academic Search

We present a method of constructing an orthomodular poset from a relation algebra. This technique is used to show that the decompositions of any algebraic, topological, or relational structure naturally form an orthomod- ular poset, thereby explaining the source of orthomodularity in the ortholattice of closed subspaces of a Hilbert space. Several known methods of producing orthomodular posets are shown

JOHN HARDING

175

Preliminary evidence of early bone resorption in a sheep model of acute burn injury: an observational study.  

PubMed

Treatment with bisphosphonates within the first 10 days of severe burn injury completely prevents bone loss. We therefore postulated that bone resorption occurs early post burn and is the primary explanation for acute bone loss in these patients. Our objective was to assess bone for histological and biomechanical evidence of early resorption post burn. We designed a randomized controlled study utilizing a sheep model of burn injury. Three sheep received a 40 % total body surface area burn under isoflurane anesthesia, and three other sheep received cotton-smoke inhalation and served as control. Burned sheep were killed 5 days post procedure and controls were killed 2 days post procedure. Backscatter scanning electron microscopy was performed on iliac crests obtained immediately postmortem along with quantitative histomorphometry and compression testing to determine bone strength (Young's modulus). Blood ionized Ca was also determined in the first 24 h post procedure as was urinary CTx. Three of three sheep killed at 5 days had evidence of scalloping of the bone surface, an effect of bone resorption, whereas none of the three sheep killed at 2 days post procedure had scalloping. One of the three burned sheep killed at 5 days showed quantitative doubling of the eroded surface and halving of the bone volume compared to sham controls. Mean values of Young's modulus were approximately one third lower in the burned sheep killed at 5 days compared to controls, p = 0.08 by unpaired t test, suggesting weaker bone. These data suggest early post-burn bone resorption. Urine CTx normalized to creatinine did not differ between groups at 24 h post procedure because the large amounts of fluids received by the burned sheep may have diluted urine creatinine and CTx and because the urine volume produced by the burned sheep was threefold that of the controls. We calculated 24 h urinary CTx excretion, and with this calculation CTx excretion/24 h in the burned sheep was nearly twice that of the controls. Moreover, whole blood ionized Ca measured at 3- to 6-h intervals over the first 24 h in both burn and control sheep showed a 6 % reduction versus baseline in the burned sheep with <1 % reduction in the control animals. This sheep model was previously used to demonstrate upregulation of the parathyroid calcium-sensing receptor within the timeframe of the present study. Because both early bone resorption, supported by this study, and calcium-sensing receptor upregulation, consistent with the observed reduction in blood ionized Ca, are mediated by proinflammatory cytokines that are present as part of the post-burn systemic inflammatory response, we may postulate that post-burn upregulation of the parathyroid calcium-sensing receptor may be an adaptive response to clear the blood of excess calcium liberated by cytokine-mediated bone resorption. PMID:23784552

Klein, Gordon L; Xie, Yixia; Qin, Yi-Xian; Lin, Liangjun; Hu, Minyi; Enkhbaatar, Perenlei; Bonewald, Lynda F

2014-03-01

176

Hydrazine decomposition and other reactions  

NASA Technical Reports Server (NTRS)

This invention relates to the catalytic decomposition of hydrazine, catalysts useful for this decomposition and other reactions, and to reactions in hydrogen atmospheres generally using carbon-containing catalysts.

Armstrong, Warren E. (Inventor); La France, Donald S. (Inventor); Voge, Hervey H. (Inventor)

1978-01-01

177

UV-DROPOUT GALAXIES IN THE GOODS-SOUTH FIELD FROM WFC3 EARLY RELEASE SCIENCE OBSERVATIONS  

SciTech Connect

We combine new high sensitivity ultraviolet (UV) imaging from the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST) with existing deep HST/Advanced Camera for Surveys optical images from the Great Observatories Origins Deep Survey (GOODS) program to identify UV-dropouts, which are Lyman break galaxy (LBG) candidates at z {approx_equal} 1-3. These new HST/WFC3 observations were taken over 50 arcmin{sup 2} in the GOODS-South field as a part of the Early Release Science program. The uniqueness of these new UV data is that they are observed in three UV/optical (WFC3 UVIS) channel filters (F225W, F275W, and F336W), which allows us to identify three different sets of UV-dropout samples. We apply Lyman break dropout selection criteria to identify F225W-, F275W-, and F336W-dropouts, which are z {approx_equal} 1.7, 2.1, and 2.7 LBG candidates, respectively. We use multi-wavelength imaging combined with available spectroscopic and photometric redshifts to carefully access the validity of our UV-dropout candidates. Our results are as follows: (1) these WFC3 UVIS filters are very reliable in selecting LBGs with z {approx_equal} 2.0, which helps to reduce the gap between the well-studied z {approx}> 3 and z {approx} 0 regimes; (2) the combined number counts with average redshift z {approx_equal} 2.2 agree very well with the observed change in the surface densities as a function of redshift when compared with the higher redshift LBG samples; and (3) the best-fit Schechter function parameters from the rest-frame UV luminosity functions at three different redshifts fit very well with the evolutionary trend of the characteristic absolute magnitude, M*, and the faint-end slope, {alpha}, as a function of redshift. This is the first study to illustrate the usefulness of the WFC3 UVIS channel observations to select z {approx}< 3 LBGs. The addition of the new WFC3 on the HST has made it possible to uniformly select LBGs from z {approx_equal} 1 to z {approx_equal} 9 and significantly enhance our understanding of these galaxies using HST sensitivity and resolution.

Hathi, N. P. [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States); Ryan, R. E. [Department of Physics and Astronomy, University of California, Davis, CA 92616 (United States); Cohen, S. H.; Windhorst, R. A.; Rutkowski, M. J. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287-1404 (United States); Yan, H. [Center for Cosmology and AstroParticle Physics, Ohio State University, Columbus, OH 43210 (United States); McCarthy, P. J. [Observatories of the Carnegie Institute of Washington, Pasadena, CA 91101 (United States); O'Connell, R. W. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904-4325 (United States); Koekemoer, A. M.; Bond, H. E. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Balick, B. [Department of Astronomy, University of Washington, Seattle, WA 98195-1580 (United States); Calzetti, D. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Disney, M. J. [School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA (United Kingdom); Dopita, M. A. [Research School of Astronomy and Astrophysics, The Australian National University, ACT 2611 (Australia); Frogel, Jay A. [Association of Universities for Research in Astronomy, Washington, DC 20005 (United States); Hall, D. N. B. [Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States); Holtzman, J. A. [Department of Astronomy, New Mexico State University, Las Cruces, NM 88003 (United States); Kimble, R. A. [NASA-Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Paresce, F. [Istituto di Astrofisica Spaziale e Fisica Cosmica, INAF, Via Gobetti 101, 40129 Bologna (Italy); Saha, A., E-mail: Nimish.Hathi@ucr.ed [National Optical Astronomy Observatories, Tucson, AZ 85726-6732 (United States)

2010-09-10

178

ELEMENTAL ABUNDANCES IN THE X-RAY GAS OF EARLY-TYPE GALAXIES WITH XMM-NEWTON AND CHANDRA OBSERVATIONS  

SciTech Connect

The source of hot gas in elliptical galaxies is thought to be due to stellar mass loss, with contributions from supernova (SN) events and possibly from infall from a surrounding environment. This picture predicts supersolar values for the metallicity of the gas toward the inner part of the galaxy, which can be tested by measuring the gas phase abundances. We use high-quality data for 10 nearby early-type galaxy from XMM-Newton, featuring both the European Photon Imaging Camera and the Reflection Grating Spectrometer, where the strongest emission lines are detected with little blending; some Chandra data are also used. We find excellent consistency in the elemental abundances between the different XMM-Newton instruments and good consistency with Chandra. Differences in abundances with aperture size and model complexity are examined, but large differences rarely occur. For a two-temperature thermal model plus a point source contribution, the median Fe and O abundances are 0.86 and 0.44 of the solar value, while Si and Mg abundances are similar to that for Fe. This is similar to stellar abundances for these galaxies but SNe were expected to enhance the gas phase abundances considerably, which is not observed.

Ji Jun; Irwin, Jimmy A.; Athey, Alex; Bregman, Joel N.; Lloyd-Davies, Edward J. [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States)], E-mail: jijun@umich.edu, E-mail: jairwin@umich.edu, E-mail: athey@arlut.utexas.edu, E-mail: jbregman@umich.edu, E-mail: radix@freeshell.org

2009-05-10

179

HF radar observations of Pc 5 field line resonances in the midnight/early morning MLT sector  

NASA Technical Reports Server (NTRS)

The technique of F region sounding by HF coherent radar is applied to the study of field line resonances equatorward of a region of shear flow in the early morning sector. The motions were predominantly in the geomagnetic east-west direction, indicating north-south electric fields. These oscillations had pronounced peaks in their latitudinal power distribution. For the pulsation at 1.95 mHz, a latitudinal phase shift of 180 deg was observed across the peaks in all the look directions of the radar, and a longitudinal wavelength corresponding to an m value of 3 was obtained. For the 2.6-mHz pulsation, the phase shifts across the peaks had a variation with a look direction that indicated a significant longitudinal as well as latitudinal variation; for this activity, an m value of about 16 is estimated. These features are interpreted in terms of the field line resonance theory, and the possible sources of the pulsation energy are discussed.

Ruohoniemi, J. M.; Greenwald, R. A.; Baker, K. B.; Samson, J. C.

1991-01-01

180

Ab initio molecular dynamics study on the initial chemical events in nitramines: thermal decomposition of CL-20.  

PubMed

CL-20 (2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane or HNIW) is a high-energy nitramine explosive. To improve atomistic understanding of the thermal decomposition of CL-20 gas and solid phases, we performed a series of ab initio molecular dynamics simulations. We found that during unimolecular decomposition, unlike other nitramines (e.g., RDX, HMX), CL-20 has only one distinct initial reaction channelhomolysis of the N-NO2 bond. We did not observe any HONO elimination reaction during unimolecular decomposition, whereas the ring-breaking reaction was followed by NO 2 fission. Therefore, in spite of limited sampling, that provides a mostly qualitative picture, we proposed here a scheme of unimolecular decomposition of CL-20. The averaged product population over all trajectories was estimated at four HCN, two to four NO2, two to four NO, one CO, and one OH molecule per one CL-20 molecule. Our simulations provide a detailed description of the chemical processes in the initial stages of thermal decomposition of condensed CL-20, allowing elucidation of key features of such processes as composition of primary reaction products, reaction timing, and Arrhenius behavior of the system. The primary reactions leading to NO2, NO, N 2O, and N2 occur at very early stages. We also estimated potential activation barriers for the formation of NO2, which essentially determines overall decomposition kinetics and effective rate constants for NO2 and N2. The calculated solid-phase decomposition pathways correlate with available condensed-phase experimental data. PMID:18686996

Isayev, Olexandr; Gorb, Leonid; Qasim, Mo; Leszczynski, Jerzy

2008-09-01

181

A-train CALIOP and MLS observations of early winter Antarctic polar stratospheric clouds and nitric acid in 2008  

NASA Astrophysics Data System (ADS)

A-train Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and Microwave Limb Sounder (MLS) observations are used to investigate the development of polar stratospheric clouds (PSCs) and the gas-phase nitric acid distribution in the early 2008 Antarctic winter. Observational evidence of gravity-wave activity is provided by Atmospheric Infrared Sounder (AIRS) radiances and infrared spectroscopic detection of nitric acid trihydrate (NAT) in PSCs is obtained from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS). Goddard Earth Observing System Data Assimilation System (GEOS-5 DAS) analyses are used to derive Lagrangian trajectories and to determine temperature-time histories of air parcels. We use CALIOP backscatter and depolarization measurements to classify PSCs and the MLS measurements to determine the corresponding gas-phase HNO3 as a function of temperature. For liquid PSCs the uptake of HNO3 follows the theoretical equilibrium curve for supercooled ternary solutions (STS), but at temperatures about 1 K lower as determined from GEOS-5. In the presence of solid phase PSCs, above the ice frost-point, the HNO3 depletion occurs over a wider range of temperatures (+2 to -7 K) distributed about the NAT equilibrium curve. Rapid gas-phase HNO3 depletion is first seen by MLS from from 23-25 May 2008, consisting of a decrease in the volume mixing ratio from 14 ppbv (parts per billion by volume) to 7 ppbv on the 46-32 hPa (hectopascal) pressure levels and accompanied by a 2-3 ppbv increase by renitrification at the 68 hPa pressure level. The observed region of depleted HNO3 is substantially smaller than the region bounded by the NAT existence temperature threshold. Temperature-time histories of air parcels demonstrate that the depletion is more clearly correlated with prior exposure to temperatures a few kelvin above the frost-point. From the combined data we infer the presence of large-size NAT particles with effective radii >5-7 ?m and low NAT number densities <1 × 10-3 cm-3. This denitrification event is observed close to the pole in the Antarctic vortex before synoptic temperatures first fall below the ice frost point and before the widespread occurrence of large-scale NAT PSCs. An episode of mountain wave activity detected by AIRS on 28 May 2008 led to wave-ice formation in the rapid cooling phases over the Antarctic Peninsula and Ellsworth Mountains, seeding an outbreak of NAT PSCs that were detected by CALIOP and MIPAS. The NAT clouds formed at altitudes of 18-26 km in a polar freezing belt and appear to be composed of relatively small particles with estimated effective radii of around 1 ?m and high NAT number densities >0.2 cm-3. This NAT outbreak is similar to an event previously reported from MIPAS observations in mid-June 2003.

Lambert, A.; Santee, M. L.; Wu, D. L.; Chae, J. H.

2012-03-01

182

A-train CALIOP and MLS observations of early winter antarctic polar stratospheric clouds and nitric acid in 2008  

NASA Astrophysics Data System (ADS)

A-train Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and Microwave Limb Sounder (MLS) observations are used to investigate the development of polar stratospheric clouds (PSCs) and the gas phase nitric acid distribution in the early 2008 Antarctic winter. Observational evidence of gravity-wave activity is provided by Atmospheric Infrared Sounder (AIRS) radiances and infrared spectroscopic detection of nitric acid trihydrate (NAT) in PSCs is obtained from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS). Goddard Earth Observing System Data Assimilation System (GEOS-5 DAS) analyses are used to derive Lagrangian trajectories and to determine temperature-time histories of air parcels. We use CALIOP backscatter and depolarization measurements to classify PSCs and the MLS measurements to determine the corresponding gas phase HNO3 as a function of temperature. For liquid PSCs the uptake of HNO3 follows the theoretical equilibrium curve for supercooled ternary solutions (STS), but at temperatures about 1 K lower as determined from GEOS-5. In the presence of solid phase PSCs, above the ice frost-point, the HNO3 depletion occurs over a wider range of temperatures (+2 to -7 K) distributed about the NAT equilibrium curve. Rapid gas phase HNO3 depletion is first seen by MLS from from 23-25 May 2008, consisting of a decrease in the volume mixing ratio (parts per billion by volume) from 14 ppbv to 7 ppbv on the 46-32 hPa (hectopascal) pressure levels and accompanied by a 2-3 ppbv increase by renitrification at the 68 hPa pressure level. Temperature-time histories of air parcels demonstrate that the depleted HNO3 region is more clearly correlated with prior low temperature exposure of a few kelvin above the frost-point than with either the region bounded by the NAT existence temperature threshold or the region of minimum temperatures. From the combined data we infer the presence of large-size NAT particles with effective radii >5-7 ?m and low NAT number densities <1×10-3 cm-3. This denitrification event is observed close to the pole in the Antarctic vortex before synoptic temperatures first fall below the ice frost point and before the widespread occurrence of large-scale NAT PSCs at altitudes 18-26 km in a polar freezing belt. The NAT outbreak is similar to an event previously reported from MIPAS observations in mid-June 2003 and is again linked to NAT formation via ice-seeding following an episode of mountain wave activity detected by AIRS. Subsequent wave-ice formation in the rapid cooling phases over the Antarctic Peninsula and Ellsworth Mountains is detected here by CALIOP and MIPAS. The NAT clouds appear to be composed of relatively small particles with estimated effective radii of around 1 ?m and high NAT number densities >0.2 cm-3.

Lambert, A.; Santee, M. L.; Wu, D. L.; Chae, J. H.

2011-10-01

183

Thermal decomposition of borax  

Microsoft Academic Search

Thermal decomposition of borax has been researched by thermal, XRD and FTIR methods as well as SEM microscopy. Study have\\u000a revealed that it proceeds according to the mechanism of internal reactions in the structure of the precursor as a medium.\\u000a \\u000a The following stages of the process have been distinguished: (1) dehydration, (2) internal structure reconstitution—formation\\u000a of tincalconite, (3) amorphization of

I. Waclawska

1995-01-01

184

Multicriteria approximation through decomposition  

SciTech Connect

The authors propose a general technique called solution decomposition to devise approximation algorithms with provable performance guarantees. The technique is applicable to a large class of combinatorial optimization problems that can be formulated as integer linear programs. Two key ingredients of their technique involve finding a decomposition of a fractional solution into a convex combination of feasible integral solutions and devising generic approximation algorithms based on calls to such decompositions as oracles. The technique is closely related to randomized rounding. Their method yields as corollaries unified solutions to a number of well studied problems and it provides the first approximation algorithms with provable guarantees for a number of new problems. The particular results obtained in this paper include the following: (1) the authors demonstrate how the technique can be used to provide more understanding of previous results and new algorithms for classical problems such as Multicriteria Spanning Trees, and Suitcase Packing; (2) they also show how the ideas can be extended to apply to multicriteria optimization problems, in which they wish to minimize a certain objective function subject to one or more budget constraints. As corollaries they obtain first non-trivial multicriteria approximation algorithms for problems including the k-Hurdle and the Network Inhibition problems.

Burch, C. [Carnegie Mellon Univ., Pittsburgh, PA (United States). School of Computer Science; Krumke, S. [Univ. of Wuerzburg (Germany). Dept. of Computer Science; Marathe, M. [Los Alamos National Lab., NM (United States); Phillips, C. [Sandia National Labs., Albuquerque, NM (United States). Applied Mathematics Dept.; Sundberg, E. [Rutgers Univ., NJ (United States). Dept. of Computer Science

1998-06-01

185

Multicriteria approximation through decomposition  

SciTech Connect

The authors propose a general technique called solution decomposition to devise approximation algorithms with provable performance guarantees. The technique is applicable to a large class of combinatorial optimization problems that can be formulated as integer linear programs. Two key ingredients of the technique involve finding a decomposition of a fractional solution into a convex combination of feasible integral solutions and devising generic approximation algorithms based on calls to such decompositions as oracles. The technique is closely related to randomized rounding. The method yields as corollaries unified solutions to a number of well studied problems and it provides the first approximation algorithms with provable guarantees for a number of new problems. The particular results obtained in this paper include the following: (1) The authors demonstrate how the technique can be used to provide more understanding of previous results and new algorithms for classical problems such as Multicriteria Spanning Trees, and Suitcase Packing. (2) They show how the ideas can be extended to apply to multicriteria optimization problems, in which they wish to minimize a certain objective function subject to one or more budget constraints. As corollaries they obtain first non-trivial multicriteria approximation algorithms for problems including the k-Hurdle and the Network Inhibition problems.

Burch, C. [Carnegie Mellon Univ., Pittsburgh, PA (United States). School of Computer Sciences]|[Sandia National Labs., Albuquerque, NM (United States); Krumke, S. [Univ. of Wuerzburg (Germany). Dept. of Computer Science; Marathe, M. [Los Alamos National Lab., NM (United States); Phillips, C. [Sandia National Labs., Albuquerque, NM (United States). Applied Mathematics Dept.; Sundberg, E. [Rutgers Univ., NJ (United States). Dept. of Computer Science]|[Sandia National Labs., Albuquerque, NM (United States)

1997-12-01

186

New Family of Electrochemical Cells for NOx Decomposition with Multi Layer Electro-Catalytic Electrode  

Microsoft Academic Search

A new family of electrochemical cells for NO decomposition in the presence of 10% oxygen has been designed and investigated. A strong correlation between the process of NO decomposition and the microstructure and composition of the electro-catalytic electrode was observed. The ambipolar transport properties of the composite electro-catalytic electrode and the electrochemical properties of an electrochemical cell for NO decomposition

S. Bredikhin; A. Aronin; G. Abrosimova; K. Matsuda; M. Awano

2002-01-01

187

Spatio-temporal dynamics of microcantilevers tapping on samples observed under an atomic force microscope integrated with a scanning laser Doppler vibrometer: applications to proper orthogonal decomposition and model reduction  

Microsoft Academic Search

As the use of microsystems has become more widespread, the need for reduced order models that accurately and efficiently predict their dynamic behavior has also grown. Proper orthogonal decomposition (POD) has proven to be a beneficial model-reduction tool in structural dynamics; however, its use in the development of reduced order models of microsystems from experimental data has not received much

Matthew Spletzer; Arvind Raman; Ron Reifenberger

2010-01-01

188

Use of the Earth Observing One (EO-1) Satellite for the Namibia SensorWeb Flood Early Warning Pilot  

NASA Technical Reports Server (NTRS)

The Earth Observing One (EO-1) satellite was launched in November 2000 as a one year technology demonstration mission for a variety of space technologies. After the first year, it was used as a pathfinder for the creation of SensorWebs. A SensorWeb is the integration of variety of space, airborne and ground sensors into a loosely coupled collaborative sensor system that automatically provides useful data products. Typically, a SensorWeb is comprised of heterogeneous sensors tied together with a messaging architecture and web services. Disasters are the perfect arena to use SensorWebs. One SensorWeb pilot project that has been active since 2009 is the Namibia Early Flood Warning SensorWeb pilot project. The Pilot Project was established under the auspices of the Namibian Ministry of Agriculture Water and Forestry (MAWF)/Department of Water Affairs, the Committee on Earth Observing Satellites (CEOS)/Working Group on Information Systems and Services (WGISS) and moderated by the United Nations Platform for Space-based Information for Disaster Management and Emergency Response (UN-SPIDER). The effort began by identifying and prototyping technologies which enabled the rapid gathering and dissemination of both space-based and ground sensor data and data products for the purpose of flood disaster management and water-borne disease management. This was followed by an international collaboration to build small portions of the identified system which was prototyped during that past few years during the flood seasons which occurred in the February through May timeframe of 2010 and 2011 with further prototyping to occur in 2012. The SensorWeb system features EO-1 data along with other data sets from such satellites as Radarsat, Terra and Aqua. Finally, the SensorWeb team also began to examine the socioeconomic component to determine the impact of the SensorWeb technology and how best to assist in the infusion of this technology in lesser affluent areas with low levels of basic infrastructure. This paper provides an overview of these efforts, highlighting the EO-1 usage in this SensorWeb.

Mandl, Daniel; Frye, Stuart; Cappelaere, Pat; Handy, Matthew; Policelli, Fritz; Katjizeu, McCloud; Van Langenhove, Guido; Aube, Guy; Saulnier, Jean-Francois; Sohlberg, Rob; Silva, Julie; Kussul, Nataliia; Skakun, Sergii; Ungar, Stephen; Grossman, Robert

2012-01-01

189

The development of the problem decomposition diagnostic  

NASA Astrophysics Data System (ADS)

The Problem Decomposition Diagnostic is a testing instrument designed to help determine student ability in two areas of problem solving. As the name implies, all versions of the test have been intended to gauge student ability to decompose, or break up, complex physics problems into simpler sub-problems. Additionally, later versions of the PDD sought to also examine the strategy the student would use to solve such sub-problems. This thesis is organized in a roughly chronological manner, following the development of the Problem Decomposition Diagnostic from early open response tests and interview tasks to the current multiple-choice format instrument. Both qualitative and quantitative methods were used in developing this instrument and measuring its validity. Extensive appendices include every version of the test, plus a complete laboratory course which helped inspire this work and informed a number of the aspects of the PDD.

van Domelen, David John

190

Simulation on Coupling between Nucleation and Spinodal Decomposition in a Polymer Dispersed Liquid Crystal  

NASA Astrophysics Data System (ADS)

Dynamics of polymerization-induced phase separation (PIPS) has been simulated numerically on a two-dimensional square lattice by combining time-dependent Ginzburg-Landau equation and curing kinetic. Our theory predicts that newer fluctuations form between the existing ones, leading to a reduction of length scale in the early stage of PIPS which is followed by coarsening in the late stage. Crossover behavior from nucleation to spinodal decomposition has been predicted in conformity with the experimental observation. The effect of kinetic parameters on the dynamics of polymerization-driven phase separation has been demonstrated.

Kyu, Thein; Chiu, H.-W.; Wang, X. Y.; Lee, J. H.

1997-03-01

191

Swedish Religious Education at the End of the 1960s: Classroom Observations, Early Video Ethnography and the National Curriculum of 1962  

ERIC Educational Resources Information Center

The aim of this article is to present a unique corpus of film-recorded classroom observations of sixth-grade classes (age 12-13) in the Swedish cities of Gothenburg, Partille and Trollhättan in the late 1960s. The material documents how RE could be taught in Swedish schools in line with the curriculum of Lgr 62 which internationally was an early

Flensner, K. Kittelmann; Larsson, G.

2014-01-01

192

Inter-observer agreement of standard joint counts in early rheumatoid arthritis: a comparison with grey scale ultrasonography a preliminary study  

Microsoft Academic Search

Objectives. The aims of the present study were to assess the inter-observer agreement of standard joint count and to compare clinical examination with grey scale ultrasonography (US) findings in patients with early rheumatoid arthritis (RA). Methods. The study was conducted on 44 RA patients with a disease duration of <2yrs. Clinical evaluation was performed independently by two rheumatologists for detection

F. Salaffi; E. Filippucci; M. Carotti; E. Naredo; G. Meenagh; A. Ciapetti; V. Savic; W. Grassi

2008-01-01

193

The View from the Little Chair in the Corner: Improving Teacher Practice and Early Childhood Learning (Wisdom from an Experienced Classroom Observer)  

ERIC Educational Resources Information Center

This is a down-to-earth, heart-to-heart book about what it takes to be an exceptional early childhood teacher. The author uses her experience as a classroom observer and a developmental psychologist to create a rationale for best practice--the reasoning behind the best (worst and average) classroom practice. Cindy Rzasa Bess examines a variety of…

Bess, Cindy Rzasa

2009-01-01

194

The Association between Parent Early Adult Drug Use Disorder and Later Observed Parenting Practices and Child Behavior Problems: Testing Alternate Models  

ERIC Educational Resources Information Center

This study tested the association between parent illicit drug use disorder (DUD) in early adulthood and observed parenting practices at ages 27-28 and examined the following 3 theoretically derived models explaining this link: (a) a disrupted parent adult functioning model,(b) a preexisting parent personality factor model, and (c) a disrupted…

Bailey, Jennifer A.; Hill, Karl G.; Guttmannova, Katarina; Oesterle, Sabrina; Hawkins, J. David; Catalano, Richard F.; McMahon, Robert J.

2013-01-01

195

Decomposition of the hexagonal copper hydride at high pressure  

NASA Astrophysics Data System (ADS)

The process of decomposition of hexagonal copper hydride has been observed in situ in a diamond anvil cell (DAC) using the energy dispersive X-ray diffraction (EDXRD) method. The presence and intensity of diffraction lines of the hexagonal CuH 0.8 phase have been taken as a probe for the decomposition process. The intensity of diffraction lines decreases abruptly in the vicinity of 8.4 GPa, indicating complete decomposition of the hydride. The determined value of decomposition pressure is equal to 8.4±0.6 GPa. The standard Gibbs energy of formation of 54.0±1.3 kJ mol -1 (H 2) calculated for copper hydride has been compared with the result obtained from calorimetric studies. The large discrepancy between the two values suggests that the decomposition pressure does not describe 'true' equilibrium conditions in this system.

Tkacz, M.; Burtovyy, R.

2004-10-01

196

Early postoperative serum S100? levels predict ongoing brain damage after meningioma surgery: a prospective observational study  

PubMed Central

Introduction Elevated serum levels of S100?, an astrocyte-derived protein, correlate with unfavourable neurological outcomes following cardiac surgery, neurotrauma, and resuscitation. This study evaluated whether pre-/postoperative serum S100? levels correlate with unfavourable clinical and radiological findings in patients undergoing elective meningioma resection. Methods In 52 consecutive patients admitted for meningioma surgery, serum S100? levels were determined upon admission and immediately, 24 hours, and 48 hours after surgery. All patients underwent complete pre- and postoperative neurological examination and mini-mental state examination. Radiological evaluation included preoperative magnetic resonance imaging (MRI) and postoperative computed tomography. Tumour volume, brain edema, and bleeding volume were calculated using BrainSCAN™ software. Results Preoperative S100? levels did not correlate with the tumour characteristics demonstrated by preoperative MRI (for example, tumour volume, edema volume, ventricular asymmetry, and/or midline shift). Preoperative serum S100? levels (0.065 ± 0.040 ?g/l) were significantly lower than the levels measured immediately (0.138 ± 0.081 ?g/l), 24 hours (0.142 ± 0.084 ?g/l), and 48 hours (0.155 ± 0.119 ?g/l) postoperatively (p < 0.0001). Significantly greater postcraniotomy S100? levels were observed with prolonged surgery (p = 0.039), deterioration in the mini-mental state examination (p = 0.005, 0.011, and 0.036 for pre versus immediate, 24 hours, and 48 hours postsurgery, respectively), and with postoperative brain computed tomography evidence of brain injury; bleeding was associated with higher serum S100? levels at 24 and 48 hours after surgery (p = 0.046, 95% confidence interval [CI] -0.095 to -0.001 and p = 0.034, 95% CI -0.142 to -0.006, respectively) as was the presence of midline shift (p = 0.005, 95% CI -0.136 to -0.025 and p = 0.006, 95% CI -0.186 to -0.032, respectively). Edema was associated with higher serum S100? levels immediately (p = 0.022, 95% CI -0.092 to -0.007) and at 48 hours after surgery (p = 0.017, 95% CI -0.142 to -0.026). The degree of elevation in S100? levels at 24 and 48 hours after surgery also correlated with the severity of midline shift and edema. Conclusion In patients with meningioma, serum S100? levels perform poorly as an indicator of tumour characteristics but may suggest ongoing postcraniotomy injury. Serum S100? levels may serve as a potentially useful early marker of postcraniotomy brain damage in patients undergoing elective meningioma resection.

Einav, Sharon; Shoshan, Yigal; Ovadia, Haim; Matot, Idit; Hersch, Moshe; Itshayek, Eyal

2006-01-01

197

Fulvenallene decomposition kinetics.  

PubMed

While the decomposition kinetics of the benzyl radical has been studied in depth both from the experimental and the theoretical standpoint, much less is known about the reactivity of what is likely to be its main decomposition product, fulvenallene. In this work the high temperature reactivity of fulvenallene was investigated on a Potential Energy Surface (PES) consisting of 10 wells interconnected through 11 transition states using a 1 D Master Equation (ME). Rate constants were calculated using RRKM theory and the ME was integrated using a stochastic kinetic Monte Carlo code. It was found that two main decomposition channels are possible, the first is active on the singlet PES and leads to the formation of the fulvenallenyl radical and atomic hydrogen. The second requires intersystem crossing to the triplet PES and leads to acetylene and cyclopentadienylidene. ME simulations were performed calculating the microcanonical intersystem crossing frequency using Landau-Zener theory convoluting the crossing probability with RRKM rates evaluated at the conical intersection. It was found that the reaction channel leading to the cyclopentadienylidene diradical is only slightly faster than that leading to the fulvenallenyl radical, so that it can be concluded that both reactions are likely to be active in the investigated temperature (1500-2000 K) and pressure (0.05-50 bar) ranges. However, the simulations show that intersystem crossing is rate limiting for the first reaction channel, as the removal of this barrier leads to an increase of the rate constant by a factor of 2-3. Channel specific rate constants are reported as a function of temperature and pressure. PMID:21819060

Polino, Daniela; Cavallotti, Carlo

2011-09-22

198

Litter evenness influences short-term peatland decomposition processes.  

PubMed

There is concern that changes in climate and land use could increase rates of decomposition in peatlands, leading to release of stored C to the atmosphere. Rates of decomposition are driven by abiotic factors such as temperature and moisture, but also by biotic factors such as changes in litter quality resulting from vegetation change. While effects of litter species identity and diversity on decomposition processes are well studied, the impact of changes in relative abundance (evenness) of species has received less attention. In this study we investigated effects of changes in short-term peatland plant species evenness on decomposition in mixed litter assemblages, measured as litter weight loss, respired CO(2) and leachate C and N. We found that over the 307-day incubation period, higher levels of species evenness increased rates of decomposition in mixed litters, measured as weight loss and leachate dissolved organic N. We also found that the identity of the dominant species influenced rates of decomposition, measured as weight loss, CO(2) flux and leachate N. Greatest rates of decomposition were when the dwarf shrub Calluna vulgaris dominated litter mixtures, and lowest rates when the bryophyte Pleurozium schreberi dominated. Interactions between evenness and dominant species identity were also detected for litter weight loss and leachate N. In addition, positive non-additive effects of mixing litter were observed for litter weight loss. Our findings highlight the importance of changes in the evenness of plant community composition for short-term decomposition processes in UK peatlands. PMID:20431923

Ward, Susan E; Ostle, Nick J; McNamara, Niall P; Bardgett, Richard D

2010-10-01

199

Mode decomposition evolution equations.  

PubMed

Partial differential equation (PDE) based methods have become some of the most powerful tools for exploring the fundamental problems in signal processing, image processing, computer vision, machine vision and artificial intelligence in the past two decades. The advantages of PDE based approaches are that they can be made fully automatic, robust for the analysis of images, videos and high dimensional data. A fundamental question is whether one can use PDEs to perform all the basic tasks in the image processing. If one can devise PDEs to perform full-scale mode decomposition for signals and images, the modes thus generated would be very useful for secondary processing to meet the needs in various types of signal and image processing. Despite of great progress in PDE based image analysis in the past two decades, the basic roles of PDEs in image/signal analysis are only limited to PDE based low-pass filters, and their applications to noise removal, edge detection, segmentation, etc. At present, it is not clear how to construct PDE based methods for full-scale mode decomposition. The above-mentioned limitation of most current PDE based image/signal processing methods is addressed in the proposed work, in which we introduce a family of mode decomposition evolution equations (MoDEEs) for a vast variety of applications. The MoDEEs are constructed as an extension of a PDE based high-pass filter (Europhys. Lett., 59(6): 814, 2002) by using arbitrarily high order PDE based low-pass filters introduced by Wei (IEEE Signal Process. Lett., 6(7): 165, 1999). The use of arbitrarily high order PDEs is essential to the frequency localization in the mode decomposition. Similar to the wavelet transform, the present MoDEEs have a controllable time-frequency localization and allow a perfect reconstruction of the original function. Therefore, the MoDEE operation is also called a PDE transform. However, modes generated from the present approach are in the spatial or time domain and can be easily used for secondary processing. Various simplifications of the proposed MoDEEs, including a linearized version, and an algebraic version, are discussed for computational convenience. The Fourier pseudospectral method, which is unconditionally stable for linearized the high order MoDEEs, is utilized in our computation. Validation is carried out to mode separation of high frequency adjacent modes. Applications are considered to signal and image denoising, image edge detection, feature extraction, enhancement etc. It is hoped that this work enhances the understanding of high order PDEs and yields robust and useful tools for image and signal analysis. PMID:22408289

Wang, Yang; Wei, Guo-Wei; Yang, Siyang

2012-03-01

200

Mode decomposition evolution equations  

PubMed Central

Partial differential equation (PDE) based methods have become some of the most powerful tools for exploring the fundamental problems in signal processing, image processing, computer vision, machine vision and artificial intelligence in the past two decades. The advantages of PDE based approaches are that they can be made fully automatic, robust for the analysis of images, videos and high dimensional data. A fundamental question is whether one can use PDEs to perform all the basic tasks in the image processing. If one can devise PDEs to perform full-scale mode decomposition for signals and images, the modes thus generated would be very useful for secondary processing to meet the needs in various types of signal and image processing. Despite of great progress in PDE based image analysis in the past two decades, the basic roles of PDEs in image/signal analysis are only limited to PDE based low-pass filters, and their applications to noise removal, edge detection, segmentation, etc. At present, it is not clear how to construct PDE based methods for full-scale mode decomposition. The above-mentioned limitation of most current PDE based image/signal processing methods is addressed in the proposed work, in which we introduce a family of mode decomposition evolution equations (MoDEEs) for a vast variety of applications. The MoDEEs are constructed as an extension of a PDE based high-pass filter (Europhys. Lett., 59(6): 814, 2002) by using arbitrarily high order PDE based low-pass filters introduced by Wei (IEEE Signal Process. Lett., 6(7): 165, 1999). The use of arbitrarily high order PDEs is essential to the frequency localization in the mode decomposition. Similar to the wavelet transform, the present MoDEEs have a controllable time-frequency localization and allow a perfect reconstruction of the original function. Therefore, the MoDEE operation is also called a PDE transform. However, modes generated from the present approach are in the spatial or time domain and can be easily used for secondary processing. Various simplifications of the proposed MoDEEs, including a linearized version, and an algebraic version, are discussed for computational convenience. The Fourier pseudospectral method, which is unconditionally stable for linearized the high order MoDEEs, is utilized in our computation. Validation is carried out to mode separation of high frequency adjacent modes. Applications are considered to signal and image denoising, image edge detection, feature extraction, enhancement etc. It is hoped that this work enhances the understanding of high order PDEs and yields robust and useful tools for image and signal analysis.

Wang, Yang; Wei, Guo-Wei; Yang, Siyang

2011-01-01

201

Extension to the North Atlantic oscillation using early instrumental pressure observations from Gibraltar and south-west Iceland  

Microsoft Academic Search

Early instrumental pressure measurements from Gibraltar and the Reykjavik area of Iceland have been used to extend to 1821 the homogeneous pressure series at the two locations. In winter the two sites are located close to the centres of action that comprise the North Atlantic Oscillation (NAO). The extended winter half-year record of the NAO enables recent changes in the

P. D. Jones; T. Jonsson; D. Wheeler

1997-01-01

202

A Descriptive-Comparative Study of Professional Development and Observed Quality in Early Care and Education Programs  

ERIC Educational Resources Information Center

With over 12 million children enrolled in early care and education programming across the U.S., families with children under the age of 5 years old are dependent on these programs. Although highly important, little regulation exists regarding qualifications necessary for individuals to work in these programs. Consequently, individuals in the field…

Romeyn, Rebecca

2010-01-01

203

The Observation, Documentation, and Shared Reflection Process: Preparing Early Childhood Educators to Teach in Alaska Native Communities  

Microsoft Academic Search

The eight early childhood educators who participated in this study were admitted into a 60-credit statewide distance-delivered Associate of Applied Science (AAS) degree program at the University of Alaska. All eight educators were women of Alaska Native ancestry who lived and worked in remote and rural Native communities. Seven of these teachers were employed by Head Start programs and one

Kathrin W. McCarthy; Thomas Scott Duke

2007-01-01

204

Early Detection of Changes in the North Atlantic Meridional Overturning Circulation: Implications for the Design of Ocean Observation Systems  

Microsoft Academic Search

Many climate models predict that anthropogenic greenhouse gas emissions may cause a threshold re- sponse of the North Atlantic meridional overturning circulation (MOC). These model predictions are, however, uncertain. Reducing this uncertainty can have an economic value, because it would allow for the design of more efficient risk management strategies. Early information about the MOC sensitivity to anthropogenic forcing (i.e.,

Klaus Keller; Curtis Deutsch; Matthew G. Hall; David F. Bradford

2007-01-01

205

Hydrogen iodide decomposition  

DOEpatents

Liquid hydrogen iodide is decomposed to form hydrogen and iodine in the presence of water using a soluble catalyst. Decomposition is carried out at a temperature between about 350.degree. K. and about 525.degree. K. and at a corresponding pressure between about 25 and about 300 atmospheres in the presence of an aqueous solution which acts as a carrier for the homogeneous catalyst. Various halides of the platinum group metals, particularly Pd, Rh and Pt, are used, particularly the chlorides and iodides which exhibit good solubility. After separation of the H.sub.2, the stream from the decomposer is countercurrently extracted with nearly dry HI to remove I.sub.2. The wet phase contains most of the catalyst and is recycled directly to the decomposition step. The catalyst in the remaining almost dry HI-I.sub.2 phase is then extracted into a wet phase which is also recycled. The catalyst-free HI-I.sub.2 phase is finally distilled to separate the HI and I.sub.2. The HI is recycled to the reactor; the I.sub.2 is returned to a reactor operating in accordance with the Bunsen equation to create more HI.

O'Keefe, Dennis R. (San Diego, CA); Norman, John H. (San Diego, CA)

1983-01-01

206

Solid-state decomposition kinetics of pentaerythritol tetranitrate  

SciTech Connect

Decomposition of pentaerythritol tetranitrate (PETN) was monitored at constant volume under variable pressures of NO{sub 2} using differential scanning calorimetry(DSC). Decomposition involved a slow initial reaction followed by an autocatalytic transition at longer times. The apparent induction time(time-to-maximum rate) for autocatalysis was found to be dependent upon sample mass and the initial pressure of NO{sub 2}. A global kinetic model consistent with observed product distributions and the free radical chain decomposition mechanisms proposed for simpler alkyl nitrates was found to yield calculated induction times in accord with experiment. 13 refs., 3 figs.

Pickard, J.M.

1990-01-01

207

Decomposition Pathways of Z-Selective Ruthenium Metathesis Catalysts  

PubMed Central

The decomposition of a Z-selective ruthenium metathesis catalyst and structurally similar analogs has been investigated utilizing X-ray crystallography and density functional theory. Isolated X-ray crystal structures suggest that recently reported C-H activated catalysts undergo decomposition via insertion of the alkylidene moiety into the chelating ruthenium-carbon bond followed by hydride elimination, which is supported by theoretical calculations. The resulting ruthenium hydride intermediates have been implicated in previously observed olefin migration, and thus lead to unwanted byproducts in cross metathesis reactions. Preventing these decomposition modes will be essential in the design of more active and selective Z-selective catalysts.

Herbert, Myles B.; Lan, Yu; Keitz, Benjamin K.; Liu, Peng; Endo, Koji; Day, Michael W.; Houk, K. N.; Grubbs, Robert H.

2012-01-01

208

Extension to the North Atlantic oscillation using early instrumental pressure observations from Gibraltar and south-west Iceland  

NASA Astrophysics Data System (ADS)

Early instrumental pressure measurements from Gibraltar and the Reykjavik area of Iceland have been used to extend to 1821 the homogeneous pressure series at the two locations. In winter the two sites are located close to the centres of action that comprise the North Atlantic Oscillation (NAO). The extended winter half-year record of the NAO enables recent changes in the record to be placed in the context of the period 1823-1996. The period since the early 1970s is the most prolonged positive phase of the oscillation and the late 1980s and early 1990s is the period with the highest values (strongest westerlies). The winter of 1995-1996 marked a dramatic switch in the index, with the change from 1994-1995 being the greatest change recorded from one year to the next since the series began in 1823. (The extended Gibraltar and Reykjavik monthly pressures and the NAO series can be found on the Climatic Research Unit home page, http://www.cru.uea.ac.uk/.).

Jones, P. D.; Jonsson, T.; Wheeler, D.

1997-11-01

209

A decomposition for some operators  

NASA Technical Reports Server (NTRS)

A decomposition of some operators is obtained that represents a generalization of Brown's (1953) work on quasi-normal operators. It is shown that the decomposition obtained is of most interest when the operator considered is far from being finite-dimensional. An application of the results obtained to the study of quasi-triangular operators is presented for illustration.

Morrel, B. B.

1973-01-01

210

Multilevel decompositions of functional spaces  

Microsoft Academic Search

A unified abstract framework for the multilevel decomposition of both Banach and quasi-Banach spaces is presented. The characterization\\u000a of intermediate spaces and their duals is derived from general Bernstein and Jackson inequalities. Applications to compactly\\u000a supported biorthogonal wavelet decompositions of families of Besov spaces are also given.

Claudio Canuto; Anita Tabacco

1997-01-01

211

Decomposition of Data Flow Diagrams  

Microsoft Academic Search

Data flow diagrams are an important design aid in system development. CASE tools allow data flow diagram construction and modification to be automated. Decomposition is the top-down development of a data flow diagram starting with the system inputs and the system outputs. Decomposition may also be automated, resulting in an interactive process for data flow diagram design. Adler (1988) described

Timothy Arndt; Angela Guercio

1992-01-01

212

Sonochemical acceleration of persulfate decomposition  

Microsoft Academic Search

The decomposition kinetics of potassium persulfate in aqueous solution have been investigated using a radical trapping method. The use of ultrasound was found to markedly accelerate the decomposition so that the sonochemical process at 25°C occurs at the same rate as the purely thermal reaction at 55°C. The effect of ultrasound intensity has also been studied and can be used

Gareth J. Price; Andrew A. Clifton

1996-01-01

213

Formaldehyde decomposition and oxidation on Pt(110)  

NASA Astrophysics Data System (ADS)

The decomposition reactions of formaldehyde on clean and oxygen dosed Pt(110) have been studied by LEED, XPS and TPRS. Formaldehyde is adsorbed in two states, a monolayer phase and a multilayer phase which were distinguishable by both TPRS and XPS. The saturated monolayer (corresponding to 8.06 × 10 14 molecules cm -2) desorbed at 134 K and the multilayer phase (which could not be saturated) desorbed at 112 K. The only other reaction products observed at higher temperatures were CO and H 2 produced in desorption limited processes and these reached a maximum upon saturation of the formaldehyde monolayer. The desorption spectrum of hydrogen was found to be perturbed by the presence of CO as reported by Weinberg and coworkers. It is proposed that local lifting of the clean surface (1 × 2) reconstruction is responsible for this behaviour. Analysis of the TPRS and XPS peak areas demonstrated that on the clean surface approximately 50% of the adsorbed monolayer dissociated with the remainder desorbing intact. Reaction of formaldehyde with preadsorbed oxygen resulted in the formation of H 2O (hydroxyl recombination) and CO 2 (decomposition of formate) desorbing at 200 and 262 K, respectively. The CO and H 2 desorption peaks were both smaller relative to formaldehyde decomposition on the clean surface and in particular, H 2 desorbed in a reaction limited process associated with decomposition of the formate species. No evidence was found for methane or hydrocarbon evolution in the present study under any circumstances. The results of this investigation are discussed in the light of our earlier work on the decomposition of methanol on the same platinum surface.

Attard, G. A.; Ebert, H. D.; Parsons, R.

1990-12-01

214

Perspectives on Pentaerythritol Tetranitrate (PETN) Decomposition.  

National Technical Information Service (NTIS)

This report evaluates the large body of work involving the decomposition of PETN and identifies the major decomposition routes and byproducts. From these studies it becomes apparent that the PETN decomposition mechanisms and the resulting byproducts are p...

D. M. Chambers C. L. Brackett O. D. Sparkman

2002-01-01

215

The value of tubular enzymes for early detection of acute kidney injury after liver transplantation: an observational study.  

PubMed

Tubular enzymes (TE) are early markers of acute kidney injury (AKI), but their value for liver transplant (LT) recipients is unknown. We sought to evaluate the usefulness of TE to predict AKI after LT. We enrolled Thirty-nine adult patients without AKI who had been admitted to the Intensive Care Unit (ICU). AKI was diagnosed according to the Acute Kidney Injury Network criteria. Of these patients, 23 had received orthotopic LT and 16 controls had been admitted for other conditions. Urinary lactate dehydrogenase (LDH), alkaline phosphatase (AF) and ?-glutamyl transpeptidase (?-GT) measured on days 1 and 3 of the ICU stay were normalized to urinary creatinine concentrations. AKI was diagnosed in 14 patients: 8 in the LT group and 6 in the control group. In the LT group, on the first day of the patients' stay in the ICU, urinary LDH (P = .032), AF (P = .022), and ?-GT (P = .002) were significantly higher among those who developed AKI; these elevations preceded those of serum creatinine. In forward receiver-operating characteristic (ROC) plot analysis, the areas under the ROC curves were 0.8, 0.86, and 0.92 for LDH, AF, and ?-GT, respectively. We concluded that TE determined early after LT are a helpful predictors of AKI. PMID:21094831

Santos, C; Marcelino, P; Carvalho, T; Coelho, J; Bispo, M; Mourão, L; Perdigoto, R; Barroso, E

2010-11-01

216

Identification of proteins related to early changes observed in Human hepatocellular carcinoma cells after treatment with the mycotoxin Zearalenone.  

PubMed

Zearalenone (ZEA) is a mycotoxin produced by some Fusarium species. ZEA often occur as a contaminant in cereal grains and animal feeds. Human exposure occurs by ingestion of mycotoxin-contaminated products and can cause serious health problems. It was established that this mycotoxin have an hepato, haemato, immuno and genotoxic properties (Maaroufi et al., 1996; Lioi et al., 2004). While most ZEA toxic effects have been quite well investigated, more studies are required to elucidate its mechanisms of toxicity. In order to better understand the molecular mechanisms involved in ZEA toxicity, we used a proteomic approach, to assess the early changes in protein expression initiated by ZEA in HepG2 cells. Our results showed that, after 8h of exposure, cells were still viable and showed a significant change in a number of proteins involved in diverse cellular processes. These changes may provide the early affected functions and yield further insight into mechanisms underlying the involvement of mycotoxin-induced diseases. PMID:23290424

Gazzah, Amel Chatti; Camoin, Luc; Abid, Salwa; Bouaziz, Chayma; Ladjimi, Moncef; Bacha, Hassen

2013-09-01

217

Delay and Migration of the 2008 Iwate-Miyagi Early Aftershocks, Observed Using High-Resolution Waveform Data  

NASA Astrophysics Data System (ADS)

The aftershock activity immediately following a large earthquake is usually not recorded completely in seismic catalogs (e.g., Kagan, 2004). Continuous high-resolution waveforms recorded at stations situated closely to the aftershock distributions were used in several recent studies (e.g., Peng et al., 2006; Enescu et al., 2007; Peng and Zhao, 2009) to help quantify early aftershocks. Recovering these missing early events is important for understanding the physical mechanisms of earthquake triggering, and tracking post-seismic deformation around the mainshock rupture zone. We have applied the matched-filter technique to identify early aftershocks occurred in the first day after the 2008 Iwate-Miyagi earthquake (Mw6.9), northeast Japan. The method (Peng and Zhao, 2009) uses waveforms of existing events as templates to search for similar patterns in the continuous waveform recordings. We selected 5556 template events occurred in the first month after the mainshock, which were recorded by at least six out of ten NIED, Hi-net seismic stations, located relatively close the aftershock distribution. The 3-component template seismograms, as well as the continuous waveform data recorded by the 10 stations, were 2 to 8 Hz band-pass filtered. A 4-s time window centered on the S-wave arrivals is used as waveform template window. We shift the 4-s window through the 1-day continuous waveforms and compute the cross-correlation (CC) coefficient, which we assign to its origin time by subtracting the S-wave arrival time. We stack and average the CC values for all stations and components, and compute the median absolute deviation (MAD) of the mean CC trace for each template event and use 9 times of MAD as the detection threshold (Peng and Zhao, 2009; Shelly et al., 2007). Similar to Peng and Zhao (2009), we have assigned for each detected event the same location as the corresponding template and determine its magnitude based on amplitude calibration. We have detected in this way 9727 events (M > -1.4), which is more than 5 times the number of aftershocks listed in the JMA earthquake catalog in the first day after the mainshock. The spatio-temporal patterns of early aftershocks show the following remarkable features: a) There is a ~100-s delay in the onset of aftershocks, relative to the mainshock occurrence time. To check about this delay, we have scrutinized the continuous waveforms in several high-frequency bands: 2-8, 10-20, 20-30, 30-40 and > 40 Hz and found no clear seismic events within 100 s after the mainshock; b) The aftershocks start occurring slightly north from the mainshock and expand in the next ~20 min. to the whole aftershock area; c) Most of the very early events occur outside the mainshock slip area, which suggests some kind of anti-correlation between aftershocks and mainshock slip.

Enescu, B.; Peng, Z.; Obara, K.; Takeda, T.

2010-12-01

218

Primary observation of early transtympanic steroid injection in patients with delayed treatment of noise-induced hearing loss.  

PubMed

Approximately 5% of the population worldwide suffer from varieties of noise-induced hearing loss (NIHL). Prevention and early identification remain the best methods of approaching NIHL. Over the years, numerous methods of improving the outcome in patients presenting with NIHL have been evaluated; however, these are far from sufficient. The present trial aimed to evaluate the effectiveness of early transtympanic steroid injection in patients with delayed treatment of NIHL. Because systemic steroid treatment is the most common treatment of choice in the management of NIHL, it was considered unethical to replace the first-line systemic steroid treatment with transtympanic treatment. Therefore, the present study evaluated the combination of conventional steroid treatment with a transtympanic steroid injection. A total of 53 patients diagnosed with delayed treatment of NIHL were randomized into a transtympanic group (TR group, n=27) and a control group (n=26). The TR group received the conventional steroid treatment plus four courses of additional transtympanic injections of methylprednisolone 3 days after NIHL onset, and the control group received the conventional steroid treatment. Transtympanic injection was performed through laser-assisted myringotomy (a 0.5- to 1-mm perforation was made in the tympanic membrane) under an operation microscope. A total of 51.9% of the patients in the TR group had a ?15-dB HL improvement in pure-tone average, compared with 23.1% of the patients in the control group, at the 8-week follow-up audiogram. A total of 66.7% of the patients in the TR group had an improvement of ?15% in the speech discrimination score, compared with 30.8% of patients in the control group, 8 weeks after the treatment. The differences between the two groups were statistically significant. The outcome of this trial indicates that delayed treatment of NIHL may be preferable if transtympanic therapy can be applied earlier. The large variability in the individual results indicates that additional carefully controlled studies with larger sample sizes are needed to understand the effect of early transtympanic therapy in patients with delayed treatment of NIHL. PMID:23208457

Zhou, Yide; Zheng, Guiliang; Zheng, Hongliang; Zhou, Ronjue; Zhu, Xiaomei; Zhang, Qing

2013-01-01

219

Hydroxyl radical formation during peroxynitrous acid decomposition  

SciTech Connect

Yields of O{sub 2} formed during decomposition of peroxynitrous acid (ONOOH) under widely varying medium conditions are compared to predictions based upon the assumption that the reaction involves formation of discrete {sm{underscore}bullet}OH and {sm{underscore}bullet}NO{sub 2} radicals as oxidizing intermediates. The kinetic model used includes all reactions of {sm{underscore}bullet}OH, {sm{underscore}bullet}O{sub 2}{sup {minus}}, and reactive nitrogen species known to be important under the prevailing conditions; because the rate constants for all of these reactions have been independently measured, the calculations contain no adjustable fitting parameters. The model quantitatively accounts for (1) the complex pH dependence of the O{sub 2} yields and (2) the unusual effects of NO{sub 2} {sup {minus}}, which inhibits O{sub 2} formation in neutral, but not alkaline, solutions and also reverses inhibition by organic {sm{underscore}bullet}OH scavengers in alkaline media. Other observations, including quenching of O{sub 2} yields by ferrocyanide and bicarbonate, the pressure dependence of the decomposition rate, and the reported dynamic behavior for O{sub 2} generation in the presence of H{sub 2}O{sub 2}, also appear to be in accord with the suggested mechanism. Overall, the close correspondence between observed and calculated O{sub 2} yields provides strong support for decomposition via homolysis of the ONOOH peroxo bond.

Coddington, J.W.; Hurst, J.K.; Lymar, S.V.

1999-03-24

220

Perfluoropolyalkylether decomposition on catalytic aluminas  

NASA Technical Reports Server (NTRS)

The decomposition of Fomblin Z25, a commercial perfluoropolyalkylether liquid lubricant, was studied using the Penn State Micro-oxidation Test, and a thermal gravimetric/differential scanning calorimetry unit. The micro-oxidation test was conducted using 440C stainless steel and pure iron metal catalyst specimens, whereas the thermal gravimetric/differential scanning calorimetry tests were conducted using catalytic alumina pellets. Analysis of the thermal data, high pressure liquid chromatography data, and x-ray photoelectron spectroscopy data support evidence that there are two different decomposition mechanisms for Fomblin Z25, and that reductive sites on the catalytic surfaces are responsible for the decomposition of Fomblin Z25.

Morales, Wilfredo

1994-01-01

221

Azimuthal decomposition with digital holograms.  

PubMed

We demonstrate a simple approach, using digital holograms, to perform a complete azimuthal decomposition of an optical field. Importantly, we use a set of basis functions that are not scale dependent so that unlike other methods, no knowledge of the initial field is required for the decomposition. We illustrate the power of the method by decomposing two examples: superpositions of Bessel beams and Hermite-Gaussian beams (off-axis vortex). From the measured decomposition we show reconstruction of the amplitude, phase and orbital angular momentum density of the field with a high degree of accuracy. PMID:22565722

Litvin, Igor A; Dudley, Angela; Roux, Filippus S; Forbes, Andrew

2012-05-01

222

Structural optimization by multilevel decomposition  

NASA Technical Reports Server (NTRS)

A method is described for decomposing an optimization problem into a set of subproblems and a coordination problem which preserves coupling between the subproblems. The method is introduced as a special case of multilevel, multidisciplinary system optimization and its algorithm is fully described for two level optimization for structures assembled of finite elements of arbitrary type. Numerical results are given for an example of a framework to show that the decomposition method converges and yields results comparable to those obtained without decomposition. It is pointed out that optimization by decomposition should reduce the design time by allowing groups of engineers, using different computers to work concurrently on the same large problem.

Sobieszczanski-Sobieski, J.; James, B.; Dovi, A.

1983-01-01

223

Effects observed in the ionospheric F region in the east Asian sector during the intense geomagnetic disturbances in the early part of November 2004  

NASA Astrophysics Data System (ADS)

The Sun was very active in the early part of November 2004. During the period of 8-10 November 2004, intense geomagnetic disturbances with two superstorms were observed. In a companion paper (hereinafter referred to as paper 1), the effects observed in the F region during the intense geomagnetic disturbances in the early part of November 2004 in the Latin American sector were presented. In the present paper, we investigate the effects observed in the F region during the intense geomagnetic disturbances in the early part of November 2004 in the east Asian sector. We have used the ionospheric sounding observations at Ho Chi Minh City (Vietnam) and Okinawa, Yamagawa, Kokubunji, and Wakkanai (Japan) in the present investigations. Also, GPS observations in the east Asian sector (several longitude zones) have been used to study the effect in the F region during the intense geomagnetic disturbances. The ion density versus latitudinal variations obtained by the DMSP F15 satellite orbiting at about 800 km altitude in the east Asian sector and the magnetic field data obtained at several stations in the Japanese meridian are also presented. Several important features from these observations in both the sectors during this extended period of intense geomagnetic disturbances are presented. The east Asian sector showed very pronounced effects during the second superstorm, which was preceded by two storm enhancements. It should be mentioned that around the beginning of the night on 10 November, ionospheric irregularities propagating from higher midlatitude region to low-latitude region were observed in the Japanese sector. The most intense geomagnetic field H component in that sector was observed on 10 November at L = 2.8, indicating that the auroral oval and the heating got further to low latitudes and the ionospheric irregularities observed in the Japanese sector on this night are midlatitude ionospheric disturbances associated with the second superstorm. The absence of ionospheric irregularities in the Japanese sector during the 8 November superstorm suggests that the magnetosphere-ionosphere system was possibly preconditioned (primed) when the second interplanetary structure impacted the magnetosphere.

Sahai, Y.; Becker-Guedes, F.; Fagundes, P. R.; de Jesus, R.; de Abreu, A. J.; Otsuka, Y.; Shiokawa, K.; Igarashi, K.; Yumoto, K.; Huang, C.-S.; Lan, H. T.; Saito, A.; Guarnieri, F. L.; Pillat, V. G.; Bittencourt, J. A.

2009-03-01

224

A test of an early-type contact binary model by comparing the relations obtained from theory with those from observations  

NASA Astrophysics Data System (ADS)

Contact binary systems, including massive, middle-mass and low-mass systems, have been observed. It is necessary to construct the evolutionary model for contact binary systems with all different masses. The model introduced by Huang, Song and Bi indicates some special and unique understandings of the physical processes occurring in the contact binaries. It is necessary to test whether this model can be applied to the early-type contact binaries. The best way to test a theoretical model is to know whether this model can explain the observational phenomena of such binaries. For this aim, a comparison is performed for the relations of mass-luminosity, mass-radius, and the distribution in the HR diagram obtained from the model introduced by Huang et al. and those from the astronomical observations. A good result is obtained by the comparison. This means the model can be used in calculating the evolution of early-type contact binaries, and can explain the observational phenomena of such binaries.

Song, Fen; Huang, RunQian

2012-02-01

225

From chessboard tweed to chessboard nanowire structure during pseudospinodal decomposition  

NASA Astrophysics Data System (ADS)

Microstructure evolution in complex nonlinear systems is of great interest from both scientific and engineering viewpoints. Here, we consider an important case of such an evolution, a coherent decomposition of a homogeneous parent phase involving the symmetry-lifting crystal lattice rearrangement of the product phase. It is shown that under certain conditions the transformation develops as a pseudospinodal decomposition, which is defined as a transformation with continuous changes of the compositions of both decomposed phases towards their equilibrium values. The pseudospinodal decomposition starts by the formation of a nanodomain precursor state with a so-called tweed structure. The three-dimensional modelling demonstrates that this tweed structure has an underlying chessboard feature, and this arrangement is a template for the further microstructure development that eventually produces a coherent two-phase chessboard nanowire pattern. The proposed theory and modelling describe the mechanism of the pseudospinodal decomposition and predict all observed three-dimensional features of the chessboard structure.

Ni, Yong; Khachaturyan, Armen G.

2009-05-01

226

Nonequilibrium adiabatic molecular dynamics simulations of methane clathrate hydrate decomposition.  

PubMed

Nonequilibrium, constant energy, constant volume (NVE) molecular dynamics simulations are used to study the decomposition of methane clathrate hydrate in contact with water. Under adiabatic conditions, the rate of methane clathrate decomposition is affected by heat and mass transfer arising from the breakup of the clathrate hydrate framework and release of the methane gas at the solid-liquid interface and diffusion of methane through water. We observe that temperature gradients are established between the clathrate and solution phases as a result of the endothermic clathrate decomposition process and this factor must be considered when modeling the decomposition process. Additionally we observe that clathrate decomposition does not occur gradually with breakup of individual cages, but rather in a concerted fashion with rows of structure I cages parallel to the interface decomposing simultaneously. Due to the concerted breakup of layers of the hydrate, large amounts of methane gas are released near the surface which can form bubbles that will greatly affect the rate of mass transfer near the surface of the clathrate phase. The effects of these phenomena on the rate of methane hydrate decomposition are determined and implications on hydrate dissociation in natural methane hydrate reservoirs are discussed. PMID:20406006

Alavi, Saman; Ripmeester, J A

2010-04-14

227

Ceramic decomposition under irradiation, 1987  

SciTech Connect

Our quantitative determinations of the decomposition of thin film and bulk ceramic materials during electron microscopy has shown that the radiation damage effect is a complex one depending dielectric and thermochemical properties. In low melting temperature glasses, for example, much of the activity is due to field enhanced diffusion of low atomic weight species. This is particularly true of bulk specimens and for the case of binary soda-borosilicate glass the sodium depletion in the SEM can be quantitatively described in terms of this effect. Studies with thin specimens of refractory carbides show that in these materials the carbon depletion is due to direct displacement processes and that here the electric fields give rise to recombination effects. The studies of ceramic thin films suitable for reference standards is continuing as a joint effort with the Rockwell Science Center. Work is in progress to describe the in plane crystallization that is observed in terms of the latent heat involved and the configurational entropy of the propagating interface.

Howitt, D.G.

1987-01-01

228

Algorithm for singular value decomposition  

SciTech Connect

An iterative algorithm for the singular value decomposition (SVD) of a non-zero m x n matrix M is described and illustrated numerically. Derivations of the algorithm and sufficient conditions for convergence are outlined.

Ross, D.C.

1984-01-01

229

Decomposition-Aggregation Stability Analysis.  

National Technical Information Service (NTIS)

This report presents the development and description of the decomposition aggregation approach to stability investigations of high dimension mathematical models of dynamic systems. The high dimension vector differential equation describing a large dynamic...

D. D. Siljak S. Weissenberger S. M. Cuk

1973-01-01

230

Catalyst for sodium chlorate decomposition  

NASA Technical Reports Server (NTRS)

Production of oxygen by rapid decomposition of cobalt oxide and sodium chlorate mixture is discussed. Cobalt oxide serves as catalyst to accelerate reaction. Temperature conditions and chemical processes involved are described.

Wydeven, T.

1972-01-01

231

The Things We Care to See: The Effects of Rotated Protocol Immersion on the Emergence of Early Observing Responses  

ERIC Educational Resources Information Center

We tested the effect of a Rotated Protocol Immersion package on the emergence of observing responses as prerequisites for more complex verbal developmental capabilities. Three elementary aged students between the ages of 6 and 7 participated. They were diagnosed with autism spectrum disabilities. The treatment condition consisted of total…

Keohane, Dolleen-Day; Luke, Nicole; Greer, R. Douglas

2008-01-01

232

Quality in Kindergarten Classrooms: Observational Evidence for the Need to Increase Children's Learning Opportunities in Early Education Classrooms  

ERIC Educational Resources Information Center

Research Findings: Using observational data gathered in 730 kindergarten classrooms in 6 states, the present study focuses on the quality of children's learning opportunities in kindergarten classrooms. Findings show that overall, children experience moderate to low levels of quality in the areas of classroom organization and instructional support…

La Paro, Karen M.; Hamre, Bridget K.; Locasale-Crouch, Jennifer; Pianta, Robert C.; Bryant, Donna; Early, Dianne; Clifford, Richard; Barbarin, Oscar; Howes, Carollee; Burchinal, Margaret

2009-01-01

233

From dogmatic discussions to observations and planned experiments: Some examples from early aurora borealis research in Finland  

Microsoft Academic Search

With examples we show the change in physics research methods in Finland. From mere passive observations physics moved towards experiments and even planning special experiments to solve particular problems, the goal being to establish a theory of the phenomenon under study. In this way a fruitful interaction between experiment and theory emerged. Individual learning repeat this progression.

Peter Holmberg

1996-01-01

234

From dogmatic discussions to observations and planned experiments: Some examples from early aurora borealis research in Finland  

NASA Astrophysics Data System (ADS)

With examples we show the change in physics research methods in Finland. From mere passive observations physics moved towards experiments and even planning special experiments to solve particular problems, the goal being to establish a theory of the phenomenon under study. In this way a fruitful interaction between experiment and theory emerged. Individual learning repeat this progression.

Holmberg, Peter

1996-07-01

235

From Dogmatic Discussions to Observations and Planned Experiments: Some Examples from Early Aurora Borealis Research in Finland.  

ERIC Educational Resources Information Center

Traces the evolution of physics research methods in Finland from passive observations to planned experiments. Presents examples of planned experiments designed to solve particular problems with the goal of establishing a theory of the phenomenon under study. Contains 16 references. (JRH)

Holmberg, Peter

1996-01-01

236

Anisotropic Decomposition of Energetic Materials  

Microsoft Academic Search

Using a white x-ray synchrotron beam, we have dynamically studied radiation-induced decomposition in single crystalline PETN and TATB. By monitoring the integrated intensity of selected diffraction spots via a CCD x-ray camera as a function of time, we have found that the decomposition rate varies dramatically depending upon the orientation of the crystalline axes relative to polarized x-ray beam and

Michael Pravica; Zachary Quine; Edward Romano; Sean Bajar; Brian Yulga; Wenge Yang; Daniel Hooks

2007-01-01

237

Nontraditional tensor decompositions and applications.  

SciTech Connect

This presentation will discuss two tensor decompositions that are not as well known as PARAFAC (parallel factors) and Tucker, but have proven useful in informatics applications. Three-way DEDICOM (decomposition into directional components) is an algebraic model for the analysis of 3-way arrays with nonsymmetric slices. PARAFAC2 is a related model that is less constrained than PARAFAC and allows for different objects in one mode. Applications of both models to informatics problems will be shown.

Bader, Brett William

2010-07-01

238

Optimization by nonhierarchical asynchronous decomposition  

NASA Technical Reports Server (NTRS)

Large scale optimization problems are tractable only if they are somehow decomposed. Hierarchical decompositions are inappropriate for some types of problems and do not parallelize well. Sobieszczanski-Sobieski has proposed a nonhierarchical decomposition strategy for nonlinear constrained optimization that is naturally parallel. Despite some successes on engineering problems, the algorithm as originally proposed fails on simple two dimensional quadratic programs. The algorithm is carefully analyzed for quadratic programs, and a number of modifications are suggested to improve its robustness.

Shankar, Jayashree; Ribbens, Calvin J.; Haftka, Raphael T.; Watson, Layne T.

1992-01-01

239

Loss of diversity in wood-inhabiting fungal communities affects decomposition activity in Norway spruce wood.  

PubMed

Hundreds of wood-inhabiting fungal species are now threatened, principally due to a lack of dead wood in intensively managed forests, but the consequences of reduced fungal diversity on ecosystem functioning are not known. Several experiments have shown that primary productivity is negatively affected by a loss of species, but the effects of microbial diversity on decomposition are less studied. We studied the relationship between fungal diversity and the in vitro decomposition rate of slightly, moderately and heavily decayed Picea abies wood with indigenous fungal communities that were diluted to examine the influence of diversity. Respiration rate, wood-degrading hydrolytic enzymes and fungal community structure were assessed during a 16-week incubation. The number of observed OTUs in DGGE was used as a measure of fungal diversity. Respiration rate increased between early- and late-decay stages. Reduced fungal diversity was associated with lower respiration rates during intermediate stages of decay, but no effects were detected at later stages. The activity of hydrolytic enzymes varied among decay stages and fungal dilutions. Our results suggest that functioning of highly diverse communities of the late-decay stage were more resistant to the loss of diversity than less diverse communities of early decomposers. This indicates the accumulation of functional redundancy during the succession of the fungal community in decomposing substrates. PMID:24904544

Valentín, Lara; Rajala, Tiina; Peltoniemi, Mikko; Heinonsalo, Jussi; Pennanen, Taina; Mäkipää, Raisa

2014-01-01

240

Loss of diversity in wood-inhabiting fungal communities affects decomposition activity in Norway spruce wood  

PubMed Central

Hundreds of wood-inhabiting fungal species are now threatened, principally due to a lack of dead wood in intensively managed forests, but the consequences of reduced fungal diversity on ecosystem functioning are not known. Several experiments have shown that primary productivity is negatively affected by a loss of species, but the effects of microbial diversity on decomposition are less studied. We studied the relationship between fungal diversity and the in vitro decomposition rate of slightly, moderately and heavily decayed Picea abies wood with indigenous fungal communities that were diluted to examine the influence of diversity. Respiration rate, wood-degrading hydrolytic enzymes and fungal community structure were assessed during a 16-week incubation. The number of observed OTUs in DGGE was used as a measure of fungal diversity. Respiration rate increased between early- and late-decay stages. Reduced fungal diversity was associated with lower respiration rates during intermediate stages of decay, but no effects were detected at later stages. The activity of hydrolytic enzymes varied among decay stages and fungal dilutions. Our results suggest that functioning of highly diverse communities of the late-decay stage were more resistant to the loss of diversity than less diverse communities of early decomposers. This indicates the accumulation of functional redundancy during the succession of the fungal community in decomposing substrates.

Valentin, Lara; Rajala, Tiina; Peltoniemi, Mikko; Heinonsalo, Jussi; Pennanen, Taina; Makipaa, Raisa

2014-01-01

241

Early X-ray and optical observations of the soft gamma-ray repeater SGR0418+5729  

Microsoft Academic Search

Emission of two short hard X-ray bursts on 2009 June 5 disclosed the existence of a new soft gamma-ray repeater, now catalogued as SGR0418+5729. After a few days, X-ray pulsations at a period of 9.1s were discovered in its persistent emission. SGR0418+5729 was monitored almost since its discovery with the Rossi X-ray Timing Explorer (2-10keV energy range) and observed many

P. Esposito; G. L. Israel; R. Turolla; A. Tiengo; D. Götz; A. de Luca; R. P. Mignani; S. Zane; N. Rea; V. Testa; P. A. Caraveo; S. Chaty; F. Mattana; S. Mereghetti; A. Pellizzoni; P. Romano

2010-01-01

242

UV-dropout Galaxies in the Goods-South Field from WFC3 Early Release Science Observations  

Microsoft Academic Search

We combine new high sensitivity ultraviolet (UV) imaging from the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST) with existing deep HST\\/Advanced Camera for Surveys optical images from the Great Observatories Origins Deep Survey (GOODS) program to identify UV-dropouts, which are Lyman break galaxy (LBG) candidates at z ~= 1-3. These new HST\\/WFC3 observations were taken over

N. P. Hathi; R. E. Ryan Jr.; S. H. Cohen; H. Yan; R. A. Windhorst; P. J. McCarthy; R. W. O'Connell; A. M. Koekemoer; M. J. Rutkowski; B. Balick; H. E. Bond; D. Calzetti; M. J. Disney; M. A. Dopita; Jay A. Frogel; D. N. B. Hall; J. A. Holtzman; R. A. Kimble; F. Paresce; A. Saha; J. I. Silk; J. T. Trauger; A. R. Walker; B. C. Whitmore; E. T. Young

2010-01-01

243

EARLY RADIO AND X-RAY OBSERVATIONS OF THE YOUNGEST NEARBY TYPE Ia SUPERNOVA PTF 11kly (SN 2011fe)  

SciTech Connect

On 2011 August 24 (UT) the Palomar Transient Factory (PTF) discovered PTF11kly (SN 2011fe), the youngest and most nearby Type Ia supernova (SN Ia) in decades. We followed this event up in the radio (centimeter and millimeter bands) and X-ray bands, starting about a day after the estimated explosion time. We present our analysis of the radio and X-ray observations, yielding the tightest constraints yet placed on the pre-explosion mass-loss rate from the progenitor system of this supernova. We find a robust limit of M-dot {approx}<10{sup -8}(w/100 km s{sup -1}) M{sub sun} yr{sup -1} from sensitive X-ray non-detections, as well as a similar limit from radio data, which depends, however, on assumptions about microphysical parameters. We discuss our results in the context of single-degenerate models for SNe Ia and find that our observations modestly disfavor symbiotic progenitor models involving a red giant donor, but cannot constrain systems accreting from main-sequence or sub-giant stars, including the popular supersoft channel. In view of the proximity of PTF11kly and the sensitivity of our prompt observations, we would have to wait for a long time (a decade or longer) in order to more meaningfully probe the circumstellar matter of SNe Ia.

Horesh, Assaf; Kulkarni, S. R.; Carpenter, John; Kasliwal, Mansi M.; Ofek, Eran O. [Cahill Center for Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Fox, Derek B. [Astronomy and Astrophysics, Eberly College of Science, Pennsylvania State University, University Park, PA 16802 (United States); Quimby, Robert [IPMU, University of Tokyo, Kashiwanoha 5-1-5, Kashiwa-shi, Chiba (Japan); Gal-Yam, Avishay [Benoziyo Center for Astrophysics, Faculty of Physics, Weizmann Institute of Science, Rehovot 76100 (Israel); Cenko, S. Bradley [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); De Bruyn, A. G. [Netherlands Institute for Radio Astronomy (ASTRON), Postbus 2, NL-7990 AA Dwingeloo (Netherlands); Kamble, Atish; Wijers, Ralph A. M. J. [Center for Gravitation and Cosmology, University of Wisconsin, Milwaukee, WI 53211 (United States); Van der Horst, Alexander J. [Universities Space Research Association, NSSTC, Huntsville, AL 35805 (United States); Kouveliotou, Chryssa [Space Science Office, VP-62, NASA-Marshall Space Flight Center, Huntsville, AL 35805 (United States); Podsiadlowski, Philipp; Sullivan, Mark; Maguire, Kate [Department of Physics (Astrophysics), University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Howell, D. Andrew [Las Cumbres Observatory Global Telescope Network, Santa Barbara, CA 93117 (United States); Nugent, Peter E. [Computational Cosmology Center, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Gehrels, Neil [NASA-Goddard Space Flight Center, Greenbelt, MD 20771 (United States); and others

2012-02-10

244

Early Radio and X-Ray Observations of the Youngest nearby Type Ia Supernova PTF 11kly (SN 2011fe)  

NASA Astrophysics Data System (ADS)

On 2011 August 24 (UT) the Palomar Transient Factory (PTF) discovered PTF11kly (SN 2011fe), the youngest and most nearby Type Ia supernova (SN Ia) in decades. We followed this event up in the radio (centimeter and millimeter bands) and X-ray bands, starting about a day after the estimated explosion time. We present our analysis of the radio and X-ray observations, yielding the tightest constraints yet placed on the pre-explosion mass-loss rate from the progenitor system of this supernova. We find a robust limit of \\dot{M}\\lesssim 10^{-8}(w/100\\,km\\,s^{-1})\\,M_{\\odot }\\,yr^{-1} from sensitive X-ray non-detections, as well as a similar limit from radio data, which depends, however, on assumptions about microphysical parameters. We discuss our results in the context of single-degenerate models for SNe Ia and find that our observations modestly disfavor symbiotic progenitor models involving a red giant donor, but cannot constrain systems accreting from main-sequence or sub-giant stars, including the popular supersoft channel. In view of the proximity of PTF11kly and the sensitivity of our prompt observations, we would have to wait for a long time (a decade or longer) in order to more meaningfully probe the circumstellar matter of SNe Ia.

Horesh, Assaf; Kulkarni, S. R.; Fox, Derek B.; Carpenter, John; Kasliwal, Mansi M.; Ofek, Eran O.; Quimby, Robert; Gal-Yam, Avishay; Cenko, S. Bradley; de Bruyn, A. G.; Kamble, Atish; Wijers, Ralph A. M. J.; van der Horst, Alexander J.; Kouveliotou, Chryssa; Podsiadlowski, Philipp; Sullivan, Mark; Maguire, Kate; Howell, D. Andrew; Nugent, Peter E.; Gehrels, Neil; Law, Nicholas M.; Poznanski, Dovi; Shara, Michael

2012-02-01

245

Early Radio and X-Ray Observations of the Youngest Nearby Type Ia Supernova PTF 11kly (SN 2011fe)  

NASA Technical Reports Server (NTRS)

On August 24 (UT) the Palomar Transient Factory (PTF) discovered PTF11kly (SN 2011fe), the youngest and most nearby type Ia supernova (SN Ia) in decades. We followed this event up in the radio (centimeter and millimeter bands) and X-ray bands, starting about a day after the estimated explosion time. We present our analysis of the radio and X-ray observations, yielding the tightest constraints yet placed on the pre-explosion mass-loss rate from the progenitor system of this supernova. We find a robust limit of M(raised dot) less than or equal to 10(exp -8) (w /100 kilometers per second ) solar mass yr(exp -1) from sensitive X-ray non-detections, as well as a similar limit from radio data, which depends, however, on assumptions about microphysical parameters. We discuss our results in the context of single-degenerate models for SNe Ia and find that our observations modestly disfavor symbiotic progenitor models involving a red giant donor, but cannot constrain systems accreting from main sequence or sub-giant stars, including the popular supersoft channel. In view of the proximity of PTF11kly and the sensitivity of our prompt observations we would have to wait for a long time (decade or longer) in order to more meaningfully probe the circumstellar matter of Ia supernovae.

Horesh, Assaf; Kulkarni, S. R.; Fox, Derek B.; Carpenter, John; Kasliwal, Mansi M.; Ofek, Eran O.; Quimby, Robert; Gal-Yam, Avishay; Cenko, S. Bradley; deBruyn, A. G.; Kamble, Atish; Wijers, Ralph A. M. J.; vanderHorst, Alexander J.; Kouveliotou, Chryssa; Podsiadlowski, Philipp; Sullivan, Mark; Maguire, Kate; Howell, D. Andrew; Nugent, Peter E.; Gehrels, Neil; Law, Nicolas M.; Poznanski, Dovi; Shara, Michael

2012-01-01

246

THE SIZE EVOLUTION OF PASSIVE GALAXIES: OBSERVATIONS FROM THE WIDE-FIELD CAMERA 3 EARLY RELEASE SCIENCE PROGRAM  

SciTech Connect

We present the size evolution of passively evolving galaxies at z {approx} 2 identified in Wide-Field Camera 3 imaging from the Early Release Science program. Our sample was constructed using an analog to the passive BzK galaxy selection criterion, which isolates galaxies with little or no ongoing star formation at z {approx}> 1.5. We identify 30 galaxies in {approx}40 arcmin{sup 2} to H < 25 mag. By fitting the 10-band Hubble Space Telescope photometry from 0.22 {mu}m {approx}< {lambda}{sub obs} {approx}< 1.6 {mu}m with stellar population synthesis models, we simultaneously determine photometric redshift, stellar mass, and a bevy of other population parameters. Based on the six galaxies with published spectroscopic redshifts, we estimate a typical redshift uncertainty of {approx}0.033(1 + z). We determine effective radii from Sersic profile fits to the H-band image using an empirical point-spread function. By supplementing our data with published samples, we propose a mass-dependent size evolution model for passively evolving galaxies, where the most massive galaxies (M{sub *} {approx} 10{sup 11} M{sub Sun }) undergo the strongest evolution from z {approx} 2 to the present. Parameterizing the size evolution as (1 + z){sup -{alpha}}, we find a tentative scaling of {alpha} Almost-Equal-To (- 0.6 {+-} 0.7) + (0.9 {+-} 0.4)log (M{sub *}/10{sup 9} M{sub Sun }), where the relatively large uncertainties reflect the poor sampling in stellar mass due to the low numbers of high-redshift systems. We discuss the implications of this result for the redshift evolution of the M{sub *}-R{sub e} relation for red galaxies.

Ryan, R. E. Jr. [Physics Department, University of California, Davis, CA 95616 (United States); McCarthy, P. J. [Observatories of the Carnegie Institute of Washington, Pasadena, CA 91101 (United States); Cohen, S. H.; Rutkowski, M. J.; Mechtley, M. R.; Windhorst, R. A. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States); Yan, H. [Center for Cosmology and Astroparticle Physics, Ohio State University, Columbus, OH 43210 (United States); Hathi, N. P. [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States); Koekemoer, A. M.; Bond, H. E.; Bushouse, H. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); O'Connell, R. W. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States); Balick, B. [Department of Astronomy, University of Washington, Seattle, WA 98195 (United States); Calzetti, D. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Crockett, R. M. [Department of Physics, University of Oxford, Oxford OX1 3PU (United Kingdom); Disney, M. [School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA (United Kingdom); Dopita, M. A. [Research School of Astronomy and Astrophysics, The Australian National University, Weston Creek, ACT 2611 (Australia); Frogel, J. A. [Galaxies Unlimited, Lutherville, MD 21093 (United States); Hall, D. N. B. [Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States); Holtzman, J. A., E-mail: rryan@physics.ucdavis.edu [Department of Astronomy, New Mexico State University, Las Cruces, NM 88003 (United States); and others

2012-04-10

247

A review of myrmecophily in ant nest beetles (Coleoptera: Carabidae: Paussinae): linking early observations with recent findings.  

PubMed

Myrmecophily provides various examples of how social structures can be overcome to exploit vast and well-protected resources. Ant nest beetles (Paussinae) are particularly well suited for ecological and evolutionary considerations in the context of association with ants because life habits within the subfamily range from free-living and predatory in basal taxa to obligatory myrmecophily in derived Paussini. Adult Paussini are accepted in the ant society, although parasitising the colony by preying on ant brood. Host species mainly belong to the ant families Myrmicinae and Formicinae, but at least several paussine genera are not host-specific. Morphological adaptations, such as special glands and associated tufts of hair (trichomes), characterise Paussini as typical myrmecophiles and lead to two different strategical types of body shape: while certain Paussini rely on the protective type with less exposed extremities, other genera access ant colonies using glandular secretions and trichomes (symphile type). We compare these adaptations with other taxonomic groups of insects by joining contemporary research and early sources and discuss the possibility of an attracting or appeasing effect of the secretion. Species that are ignored by their host ants might use chemical mimicry instead. Furthermore, vibrational signals may contribute to ant-beetle communication, and chemical signals have proven to play a role in host finding. The powerful defense chemistry of paussines as "bombardier beetles" is not used in contact with host ants. We attempt to trace the evolution of myrmecophily in paussines by reviewing important aspects of the association between paussine beetles and ants, i.e. morphological and potential chemical adaptations, life cycle, host specificity, alimentation, parasitism and sound production. PMID:17563864

Geiselhardt, Stefanie F; Peschke, Klaus; Nagel, Peter

2007-11-01

248

Comparison of hepatic adaptation in extreme metabolic phenotypes observed in early lactation dairy cows on-farm.  

PubMed

The aim was to study the variation in metabolic responses in early-lactating dairy cows (n = 232) on-farm that were pre-selected for a high milk fat content (>45 g/l) and a high fat/protein ratio in milk (>1.5) in their previous lactation. Blood was assayed for concentrations of metabolites and hormones. Liver was measured for mRNA abundance of 25 candidate genes encoding enzymes and receptors involved in gluconeogenesis (6), fatty acid ?-oxidation (6), fatty acid and triglyceride synthesis (5), cholesterol synthesis (4), ketogenesis (2) and the urea cycle (2). Two groups of cows were formed based on the plasma concentrations of glucose, non-esterified fatty acids (NEFA) and ?-hydroxybutyric acid (BHBA) (GRP+, high metabolic load; glucose <3.0 mm, NEFA >300 ?m and BHBA >1.0 mm, n = 30; GRP-, low metabolic load; glucose >3.0 mm, NEFA <300 ?m and BHBA <1.0 mm, n = 30). No differences were found between GRP+ and GRP- for the milk yield at 3 weeks post-partum, but milk fat content was higher (p < 0.01) for GRP+ than for GRP-. In week 8 post-partum, milk yield was higher in GRP+ in relation to GRP- (37.5 vs. 32.5 kg/d; p < 0.01). GRP+ in relation to GRP- had higher (p < 0.001) NEFA and BHBA and lower glucose, insulin, IGF-I, T3 , T4 concentrations (p < 0.01). The mRNA abundance of genes related to gluconeogenesis, fatty acid ?-oxidation, fatty acid and triglyceride synthesis, cholesterol synthesis and the urea cycle was different in GRP+ compared to GRP- (p < 0.05), although gene transcripts related to ketogenesis were similar between GRP+ and GRP-. In conclusion, high metabolic load post-partum in dairy cows on-farm corresponds to differences in the liver in relation to dairy cows with low metabolic load, even though all cows were pre-selected for a high milk fat content and fat/protein ratio in milk in their previous lactation. PMID:24033645

van Dorland, H A; Graber, M; Kohler, S; Steiner, A; Bruckmaier, R M

2014-08-01

249

A thermal desorption study of the kinetics of uranium hydride decomposition  

NASA Astrophysics Data System (ADS)

The decomposition of uranium hydride powder was studied using thermal desorption spectroscopy (TDS). In the TDS spectra, three distinct decomposition peaks were observed. However, only the high temperature peak was associated with an activation energy, calculated to be 43 kJ/mol H. This activation energy was used to construct outgassing diagrams that can be used to estimate the temperature and time dependence of UH3 decomposition. Potential models for explaining the three decomposition peaks and, thus, the decomposition mechanism are also presented and compared with H desorption energies calculated from first principles. Additional experiments on ?-U coupons containing UH3 corrosion pits were also performed. In those samples in excess of 6 peaks are observed. It is shown that the first three hydrogen peaks are related to the decomposition of UH3.

Lillard, R. S.; Taylor, C. D.; Wermer, J. R.; Mara, N. A.; Cooley, J. C.

2014-01-01

250

The influence of minerals on decomposition of the n-alkyl-?-amino acid norvaline under hydrothermal conditions  

NASA Astrophysics Data System (ADS)

Laboratory experiments were conducted to observe the effect of iron oxide and sulfide minerals on decomposition reactions of norvaline, a representative of a group of alkyl-?-amino acids observed in meteorites and prebiotic synthesis experiments. The primary products observed during heating of aqueous solutions of norvaline at temperatures of 156-186 °C in the presence of minerals included CO2, NH3, butyric acid, and valeric acid. The products indicated that norvaline predominantly decomposed by a combination of pathways that included both decarboxylation followed rapidly by oxidative deamination (norvaline ? butanamide + CO2 ? butyric acid + NH3) and deamination directly to valeric acid (norvaline ? valeric acid + NH3). An experiment performed with alanine under similar conditions showed it decomposed by analogous reactions that produced acetic and propionic acids along with CO2 and NH3. For both amino acids, the presence of minerals accelerated decomposition rates as well as altered the final products of reaction, when compared with decomposition in the absence of mineral substrates. In addition, decomposition of norvaline was found to proceed much faster in the presence of the mineral assemblage hematite-magnetite-pyrite (HMP) than with the assemblage pyrite-pyrrhotite-magnetite (PPM), a trend that has been observed for several other organic compounds. The influence of minerals on decomposition reactions of these amino acids appears to be attributable to a combination of surface catalysis and production of dissolved sulfur compounds. Overall, the results indicate that minerals may exert a substantial influence on amino acid stability in many geologic environments, and emphasize the need to consider the impact of minerals when evaluating the lifetimes and decomposition rates of amino acids in terrestrial and planetary systems. Estimated half-lives for alkyl-?-amino acids based on the experimental results indicate that moderately hot hydrothermal environments (<˜100 °C) would have been the most favorable for accumulation of these amino acids in the early solar system, and that the predominance of alkyl-?-amino acids in some meteorites may only be compatible with temperature remaining below about 60 °C following their formation.

McCollom, Thomas M.

2013-03-01

251

X-Ray, UV, and Optical Observations of Supernova 2006bp with Swift: Detection of Early X-Ray Emission  

NASA Technical Reports Server (NTRS)

We present results on the X-ray and optical/UV emission from the Type IIP supernova (SN) 2006bp and the interaction of the SW shock with its environment, obtained with the X-Ray Telescope (XRT) and UV/Optical Telescope (UVOT) on-board the Swift observatory. SN 2006bp is detected in X-rays at a 4.5 sigmalevel of significance in the merged XRT data from days 1 to 12 after the explosion. If the (0.2-10 keV band) X-ray luminosity of L(sub 0.2-10) = (1.8 plus or minus 0.4) x l0(exp 39 ergs s(exp -1) is caused by interaction of the SN shock with circumstellar material (CSM), deposited by a stellar wind from the progenitor's companion star, a mass-loss rate of M is approximately 2x10(exp -6) solar mass yr(exp -1) (v(sub w)/10 km s(exp -l) is inferred. The mass-loss rate is one of the lowest ever recorded for a core-collapse SN and consistent with the non-detection in the radio with the VLA on days 2, 9, and 11 after the explosion. The Swift data further show a fading of the X-ray emission starting around day 12 after the explosion. In combination with a follow-up XMM-Newton observation obtained on day 21 after the explosion, an X-ray rate of decline Lx, varies as t(exp -n) with index n = 1.2 plus or minus 0.6 is inferred. Since no other SN has been detected in X-rays prior to the optical peak and since Type IIP SNe have an extended 'plateau' phase in the optical, we discuss the scenario that the X-rays might be due to inverse Compton scattering of photospheric optical photons off relativistic electrons produced in circumstellar shocks. However, due to the high required value of the Lorentz factor (approximately 10-100), inconsistent with the ejecta velocity inferred from optical line widths, we conclude that Inverse Compton scattering is an unlikely explanation for the observed X-ray emission. The fast evolution of the optical/ultraviolet (1900-5500A) spectral energy distribution and the spectral changes observed with Swift reveal the onset of metal line-blanketing and cooling of the expanding photosphere during the first few weeks after the outburst.

Immler, S.; Brown, P. J.; Milne, P.; Dessart, L.; Mazzali, P. A.; Landsman, W.; Gehrels, N.; Petre, R.; Burrows, D. N.; Nousek, J. A.; Chevalier, R. A.; Williams, C. L.; Koss, M.; Stockdale, C. J.; Kelley, M. T.; Weiler, K. W.; Holland, S. T.; Pian, E.; Roming, P. W. A.; Pooley, D.; Nomoto, K.; Greiner, J.; Campana, S.; Soderberg, A. M.

2007-01-01

252

Cassini ISS Observations Of The Early Stages Of The Formation Of Titan's South Polar Hood And Vortex In 2012  

NASA Astrophysics Data System (ADS)

Northern spring equinox on Titan occurred on August 11, 2009. In March of 2012 the Imaging Science Subsystem (ISS) on the Cassini spacecraft saw the first evidence for the formation of a polar hood in the atmosphere above Titan’s south pole. Views of the limb showed an optical thickening primarily at about 360 km altitude across a few degrees of latitude centered on the pole. Images of Titan in front of Saturn provide a nearly direct measure of the line-of-sight optical depth as a function of latitude and altitude from about 250 km and higher. Two or more distinct layers are seen, both near the pole and at other latitudes. The highest of these, near 360 km altitude, hosts the embryonic polar hood. On June 27, 2012 ISS observed the pole from high latitude. These images show a distinct and unusual cloudy patch, elongated and not centered on the pole and with an elevated perimeter. The morphology and color indicate an unfamiliar (for Titan) composition and dynamical regime. The interior of the feature consists of concentrations of cloud/haze organized on spatial scales of tens of kilometers. Its morphology is reminiscent of the open cellular convection sometimes seen in the atmospheric boundary layer over Earth’s oceans under conditions of large-scale subsidence. Unlike Earth, where such convection is forced by large surface heat fluxes or the onset of drizzle, convection at 360 km on Titan is more likely to be driven from above by radiative cooling. During the 9 hours we observed Titan, this feature completed a little over one rotation around the pole, providing direct evidence for a polar vortex rotating at a rate roughly consistent with angular-momentum-conserving flow for air displaced from the equator. Part of this work was performed by the Jet Propulsion Laboratory, California Institute of Technology.

West, Robert A.; Del Genio, A.; Perry, J.; Ingersoll, A. P.; Turtle, E. P.; Porco, C.; Ovanessian, A.

2012-10-01

253

Early X-ray and optical observations of the soft gamma-ray repeater SGR0418+5729  

NASA Astrophysics Data System (ADS)

Emission of two short hard X-ray bursts on 2009 June 5 disclosed the existence of a new soft gamma-ray repeater, now catalogued as SGR0418+5729. After a few days, X-ray pulsations at a period of 9.1s were discovered in its persistent emission. SGR0418+5729 was monitored almost since its discovery with the Rossi X-ray Timing Explorer (2-10keV energy range) and observed many times with Swift (0.2-10keV). The source persistent X-ray emission faded by a factor of ~10 in about 160 d, with a steepening in the decay about 19 d after the activation. The X-ray spectrum is well described by a simple absorbed blackbody, with a temperature decreasing in time. A phase-coherent timing solution over the ~160 d time-span yielded no evidence for any significant evolution of the spin period, implying a 3? upper limit of 1.1 × 10-13s s-1 on the period derivative and of ~3 × 1013G on the surface dipole magnetic field. Phase-resolved spectroscopy provided evidence for a significant variation of the spectrum as a function of the stellar rotation, pointing to the presence of two emitting caps, one of which became hotter during the outburst. Finally, a deep observation of the field of SGR0418+5729 with the new Gran Telescopio Canarias 10.4-m telescope allowed us to set an upper limit on the source optical flux of i' > 25.1mag, corresponding to an X-ray-to-optical flux ratio exceeding 104, consistent with the characteristics of other magnetars.

Esposito, P.; Israel, G. L.; Turolla, R.; Tiengo, A.; Götz, D.; de Luca, A.; Mignani, R. P.; Zane, S.; Rea, N.; Testa, V.; Caraveo, P. A.; Chaty, S.; Mattana, F.; Mereghetti, S.; Pellizzoni, A.; Romano, P.

2010-07-01

254

Observational Evidence Against Mountain Wave Generation of Ice Clouds Leading to the Formation of NAT Clouds in Early December 1999 Within the Arctic Vortex  

NASA Astrophysics Data System (ADS)

A number of recently published papers suggest that mountain wave (or lee wave) activity in the stratosphere, producing temperatures below the ice frost point, may be the primary source of large NAT particles. We use thermal infrared radiance measurements from the Advanced Very High Resolution Radiometer (AVHRR) instruments on board the National Oceanic and Atmospheric Administration (NOAA) polar-orbiting satellites to map out regions of ice clouds produced by mountain wave cloud activity inside the Arctic vortex. Lidar observations from three DC-8 flights in early December 1999 show the presence of solid polar stratospheric cloud (PSC) Type Ia particles. By using back trajectories and superimposing the position maps on the AVHRR cloud imagery, we show that the observed solid Type Ia PSC particles could not have originated at locations of high mountain wave cloud activity. We also show that Mountain Wave Forecast Model 2.0 (MWFM-2) gridbox-averaged hemispheric hindcasts from the same time period are in agreement with the AVHRR data. Our results show that ice cloud formation in mountain wave clouds cannot explain how at least three large-scale solid HNO3 PSC structures were formed in the stratosphere in early December 1999.

Pagan, K. L.; Tabazadeh, A.; Drdla, K.; Hervig, M. E.; Eckermann, S. D.; Browell, E. V.; Legg, M. J.; Foschi, P. G.

2003-12-01

255

Observational Evidence Against Mountain-Wave Generation of Ice Nuclei as a Prerequisite for the Formation of Three Solid Nitric Acid Polar Stratospheric Clouds Observed in the Arctic in Early December 1999  

NASA Technical Reports Server (NTRS)

A number of recently published papers suggest that mountain-wave activity in the stratosphere, producing ice particles when temperatures drop below the ice frost point, may be the primary source of large NAT particles. In this paper we use measurements from the Advanced Very High Resolution Radiometer (AVHRR) instruments on board the National Oceanic and Atmospheric Administration (NOAA) polar-orbiting satellites to map out regions of ice clouds produced by stratospheric mountain-wave activity inside the Arctic vortex. Lidar observations from three DC-8 flights in early December 1999 show the presence of solid nitric acid (Type Ia or NAT) polar stratospheric clouds (PSCs). By using back trajectories and superimposing the position maps on the AVHRR cloud imagery products, we show that these observed NAT clouds could not have originated at locations of high-amplitude mountain-wave activity. We also show that mountain-wave PSC climatology data and Mountain Wave Forecast Model 2.0 (MWFM-2) raw hemispheric ray and grid box averaged hemispheric wave temperature amplitude hindcast data from the same time period are in agreement with the AVHRR data. Our results show that ice cloud formation in mountain waves cannot explain how at least three large scale NAT clouds were formed in the stratosphere in early December 1999.

Pagan, Kathy L.; Tabazadeh, Azadeh; Drdla, Katja; Hervig, Mark E.; Eckermann, Stephen D.; Browell, Edward V.; Legg, Marion J.; Foschi, Patricia G.

2004-01-01

256

Observational evidence of EHP effects on the early melting of snowpack over the Tibetan Plateau and Indian summer monsoon  

NASA Astrophysics Data System (ADS)

In this study, observational evidences are presented showing that the Indo-Gangetic Plain (IGP) regions, bounded by the high altitude Himalayan mountains, are subject to heavy loading of absorbing aerosols, i.e., black carbon and dust, which can lead to widespread enhancement warming over the Tibetan Plateau and accelerated snowmelt in the western Tibetan Plateau (WTP) and Himalayas. The two pre-monsoon seasons of high aerosol and low aerosol cases were strikingly contrasting in terms of the aerosol loading over IGP. The warming of the TP in high aerosol cases relative to low aerosol cases was widespread, covering most of the WTP and Himalayas. This warming is closely linked to patterns of the snow melt. Consistent with the Elevated Heat Pump hypothesis, we find that increased loading of absorbing aerosols over IGP in the pre-monsoon season is associated with increased heating of the upper troposphere by dynamical feedback induced by aerosol heating, and enhances the rate of snowmelt over Himalayas and the WTP in April-May, indicating that the heating of the troposphere by elevated dust and black carbon aerosols in the boreal spring can lead to widespread enhanced land-atmosphere warming, accelerated snow melt in the Himalayas and Tibetan Plateau, and enhanced precipitation in May-June over the northern India.

Sang, Jeong; Kim, Maeng-Ki; Lau, William K. M.; Kim, Kyu-Myong; Lee, Woo-Seop

2013-04-01

257

Systemic endotoxin activity correlates with clot formation: an observational study in patients with early systemic inflammation and sepsis  

PubMed Central

Introduction Inflammation and coagulation are closely linked, and both can be triggered by endotoxin. Thrombelastometry and impedance aggregometry are of diagnostic and predictive value in critically ill patients. In this observational study we investigated the correlation of endotoxin activity with thrombelasometric and aggregometric variables in patients with systemic inflammation. Methods Based on a daily screening on a tertiary academic surgical ICU, patients, as soon as they fulfilled two or more criteria for systemic inflammatory response syndrome (SIRS), were included. In whole blood we performed endotoxin activity (EA) assay, thrombelastometry (ROTEM®) and impendance aggregometry (Multiplate®). Results In total, 49 patients were included with a broad spread of EA levels of (median (minimum to maximum)) 0.27 (0.01 to 0.72), allowing expedient correlative analysis. Clot formation time (CFT) (263 s (60 to 1,438 s)) and clotting time (CT) (1,008 s (53 to 1,481 s)) showed a significant negative correlation with EA level (r = -0.38 (P < 0.005) and r = -0.29 (P < 0.05)). Positive correlations were found for alpha-angle (50° (17 to 78°), r = 0.40 (P < 0.005)) and maximum clot firmness (MCF) (55 mm (5/76), r = 0.27 (P < 0.05)). No significant correlations were found between Lysis Index at 60 minutes (LI60) and EA levels. There was no correlation between EA level and aggregometric values, or classical coagulation parameters. Conclusions In patients with systemic inflammation, increasing endotoxin concentrations correlate with increased clot formation.

2013-01-01

258

THE RESOLVED STELLAR POPULATION IN 50 REGIONS OF M83 FROM HST/WFC3 EARLY RELEASE SCIENCE OBSERVATIONS  

SciTech Connect

We present a multi-wavelength photometric study of {approx}15,000 resolved stars in the nearby spiral galaxy M83 (NGC 5236, D = 4.61 Mpc) based on Hubble Space Telescope Wide Field Camera 3 observations using four filters: F336W, F438W, F555W, and F814W. We select 50 regions (an average size of 260 pc by 280 pc) in the spiral arm and inter-arm areas of M83 and determine the age distribution of the luminous stellar populations in each region. This is accomplished by correcting for extinction toward each individual star by comparing its colors with predictions from stellar isochrones. We compare the resulting luminosity-weighted mean ages of the luminous stars in the 50 regions with those determined from several independent methods, including the number ratio of red-to-blue supergiants, morphological appearance of the regions, surface brightness fluctuations, and the ages of clusters in the regions. We find reasonably good agreement between these methods. We also find that young stars are much more likely to be found in concentrated aggregates along spiral arms, while older stars are more dispersed. These results are consistent with the scenario that star formation is associated with the spiral arms, and stars form primarily in star clusters and then disperse on short timescales to form the field population. The locations of Wolf-Rayet stars are found to correlate with the positions of many of the youngest regions, providing additional support for our ability to accurately estimate ages. We address the effects of spatial resolution on the measured colors, magnitudes, and age estimates. While individual stars can occasionally show measurable differences in the colors and magnitudes, the age estimates for entire regions are only slightly affected.

Kim, Hwihyun; Cohen, Seth H.; Windhorst, Rogier A. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287-1404 (United States); Whitmore, Bradley C.; Mutchler, Max; Bond, Howard E. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Chandar, Rupali [Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606 (United States); Saha, Abhijit [National Optical Astronomy Observatories, Tucson, AZ 85726-6732 (United States); Kaleida, Catherine C. [Cerro Tololo Inter-American Observatory, La Serena (Chile); Calzetti, Daniela [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); O'Connell, Robert W. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904-4325 (United States); Balick, Bruce [Department of Astronomy, University of Washington, Seattle, WA 98195-1580 (United States); Carollo, Marcella [Department of Physics, ETH-Zurich, Zurich 8093 (Switzerland); Disney, Michael J. [School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA (United Kingdom); Dopita, Michael A. [Mount Stromlo and Siding Spring Observatories, Research School of Astronomy and Astrophysics, Australian National University, Cotter Road, Weston Creek, ACT 2611 (Australia); Frogel, Jay A. [Galaxies Unlimited, 1 Tremblant Court, Lutherville, MD 21093 (United States); Hall, Donald N. B. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Holtzman, Jon A. [Department of Astronomy, New Mexico State University, Las Cruces, NM 88003 (United States); Kimble, Randy A. [NASA-Goddard Space Flight Center, Greenbelt, MD 20771 (United States); McCarthy, Patrick J., E-mail: hwihyun.kim@asu.edu [Observatories of the Carnegie Institution of Washington, Pasadena, CA 91101-1292 (United States); and others

2012-07-01

259

Thermal decomposition as route for silver nanoparticles  

PubMed Central

Single crystalline silver nanoparticles have been synthesized by thermal decomposition of silver oxalate in water and in ethylene glycol. Polyvinyl alcohol (PVA) was employed as a capping agent. The particles were spherical in shape with size below 10 nm. The chemical reduction of silver oxalate by PVA was also observed. Increase of the polymer concentration led to a decrease in the size of Ag particles. Ag nanoparticle was not formed in the absence of PVA. Antibacterial activity of the Ag colloid was studied by disc diffusion method.

Navaladian, S; Viswanath, RP; Varadarajan, TK

2007-01-01

260

Signatures of a Spinodal Decomposition in HIC  

NASA Astrophysics Data System (ADS)

Heavy Ions collisions were simulated using LATINO Model where a Pandharipande potential replicates internucleonic binary interaction. Fragments are detected with an Early Cluster Recognition Algorithm. A critical temperature of 10.5 MeV has been obtained using LATINO Model for Au+Au central collision with a projectile energy of 8000MeV. This temperature is greater than the one predicted by Fisher Law for excitations in the range of Fermi gas behavior. Higher order correlations predict also a primitive breakup with equal size fragments, as expected for a spinodal decompostions. These results suggest that the temperature of the spinodal decomposition is closer to the critical point as compared to the one obtained when a liquid-gas phase transition is assumed. Authors acknowledge financial support from UAM-A and access to the computational resources of UT-El Paso.

Barranon, Armando; López, Jorge

2004-10-01

261

Metric Learning Using Iwasawa Decomposition*  

PubMed Central

Finding a good metric over the input space plays a fundamental role in machine learning. Most existing techniques use the Mahalanobis metric without incorporating the geometry of positive matrices and experience difficulties in the optimization procedure. In this paper we introduce the use of Iwasawa decomposition, a unique and effective parametrization of symmetric positive definite (SPD) matrices, for performing metric learning tasks. Unlike other previously employed factorizations, the use of the Iwasawa decomposition is able to reformulate the semidefinite programming (SDP) problems as smooth convex nonlinear programming (NLP) problems with much simpler constraints. We also introduce a modified Iwasawa coordinates for rank-deficient positive semidefinite (PSD) matrices which enables the unifying of the metric learning and linear dimensionality reduction. We show that the Iwasawa decomposition can be easily used in most recent proposed metric learning algorithms and have applied it to the Neighbourhood Components Analysis (NCA). The experimental results on several public domain datasets are also presented.

Jian, Bing; Vemuri, Baba C.

2009-01-01

262

Optical observations of the early (t<5 s) ion dynamics of the CRRES G1, G9, and G11A releases  

NASA Astrophysics Data System (ADS)

Video images of the CRRES G1, G9, and G11A barium releases made at 400-500 km altitudes over the Caribbean in July 1991 have been analyzed to identify morphological features formed in the very early phases of the releases with the aim of associating specific physical processes with these features. Three features are presented: the observation that the inner edge of the ion cloud is located some distance from the release point along the orbital track (``skidding'') the formation of an elongated striation at the inner edge of the ion cloud and an ion depleted region behind the striation; and the formation of a flat neutral barium disk perpendicular to the magnetic field B that is centered some tens of kilometers from the release point. We are linking these morphological features with effects associated with the polarization of the initially dense ion cloud created by solar UV illumination. A simple physical model of the release and the polarization process is presented. Model predictions are both qualitatively and quantitatively in good agreement with the observations. The skidding distance appears to be controlled by the background ionospheric density and the size of the release; the structure in the early ion cloud is due to electric fields primarily setup and maintained by the polarization of the densest part of the ion cloud; and the neutral disk is formed by charge exchange between counterstreaming ions and neutrals outside the polarized core. For the three releases analyzed, no additional internal plasma processes nor processes coupling the release to the ionosphere appear to be critical for the formation of the observed features in the initial ion cloud.

Delamere, P. A.; Stenbaek-Nielsen, H. C.; Hampton, D. L.; Wescott, E. M.

1996-08-01

263

Reliable algorithm for modal decomposition  

NASA Technical Reports Server (NTRS)

This paper describes a reliable, general algorithm for modal decomposition in real arithmetic and its use in analyzing and synthesizing control logic for linear dynamic systems. The numerical difficulties are described associated with computing the Jordan canonical form when the system has repeated, or nearly repeated, eigenvalues. A new algorithm is described that satisfactorily solves these numerical difficulties. The relation and extension to related numerical analysis research are discussed to clarify the reliability of the techniques. Finally, its implementation as a practical modal decomposition method for efficiently computing the matrix exponential, transfer functions, and frequency response is also described.

Walker, Robert A.; Bryson, Arthur E., Jr.

1990-01-01

264

Kinetics of the pyrolytic and hydrothermal decomposition of water hyacinth.  

PubMed

The kinetics of water hyacinth decomposition using pyrolysis and hydrothermal treatment was compared. With pyrolysis, initial vaporization occurred at 453 K as determined by thermogravimetric analysis, while initial solubilisation occurred at 433 K with subcritical hydrothermal treatment. The "kinetic triplet" was determined for the ranges of 423-483 K (range I) and 473-553 K (range II) using the Coats-Redfern method for both treatments. The calculated activation energies for ranges I and II were 110 and 116 kJ/mol for conventional pyrolysis and 145 and 90 kJ/mol for hydrothermal treatment. The similar activation energies for the two temperature ranges observed for pyrolysis implied that only hemicellulose decomposition occurred. For hydrothermal treatment, both hemicellulose and cellulose decomposition occurred in temperature range II, in which a notable lower activation energy was observed. This implied hydrothermal treatment was more suitable for conversion lignocellulosic biomass under these conditions. PMID:21558054

Luo, Guang'en; Strong, P James; Wang, Hailong; Ni, Wuzhong; Shi, Weiyong

2011-07-01

265

Observations of an early Agulhas current retroflection event in 2001: A temporary cessation of inter-ocean exchange south of Africa?  

NASA Astrophysics Data System (ADS)

The exchange of heat and salt between the South Indian Ocean and South Atlantic Ocean, at the southern terminus of the Agulhas current, forms a crucial link in the global ocean circulation. It has been surmised that upstream retroflections in this current could produce temporary interruptions to the exchange, but that their impact would depend on the vertical extent of such retroflections and on their duration. The fortuitous presence at sea of a research vessel has now enabled us to investigate such an episode at subsurface levels in combination with remote sensing of the sea surface. We present here the first in situ evidence that an upstream or early retroflection can extend to a depth of well over 750 m and last for 5 months. This event was likely triggered upstream by the happenstance of two Natal Pulses, large cyclonic eddies inshore of the Agulhas current. These eddies short-circuited the Agulhas with its Return current, leading to the shedding of three large Agulhas rings in quick succession. The arrival of a third cyclonic eddy when the Retroflection was still quite retracted did not lead to another ring shedding event. The resulting early retroflection may have had the effect of stalling the shedding of Agulhas rings and their motion towards the Cape Basin. However, these early retroflections are too scarce to allow generic statements on their generation or consequences, and the relation with large-scale environmental factors. It is likely that the observed withdrawal of the retroflection into the Transkei Basin is a fortuitous result of a series of contingent interactions.

van Aken, H. M.; Lutjeharms, J. R. E.; Rouault, M.; Whittle, C.; de Ruijter, W. P. M.

2013-02-01

266

Trajectory of intensive treat-to-target disease modifying drug regimen in an observational study of an early rheumatoid arthritis cohort  

PubMed Central

Objectives Studies of early rheumatoid arthritis (RA) cohorts have analysed treatment response and prognostic factors at fixed time points. However, in treat-to-target protocols, therapeutic decision-making is dynamic and responsive to disease activity over time. To determine when a minimal residual disease response target should be expected, our primary objective was to identify the time-dependent therapeutic response to combination disease modifying antirheumatic drugs (DMARDs) for 12?months. Our secondary objective determined factors affecting this response trajectory. Design Observational cohort. Setting Treat-to-target early RA clinic in Australian tertiary referral hospital. Participants We enrolled consecutive patients attending an early arthritis clinic with symptom duration less than 12?months, who were diagnosed with RA for the first time between 2004 and 2008. 101 met these eligibility criteria and data were available at baseline through 12?months. Interventions intensive DMARDs according to a treat-to-target protocol. Primary and secondary outcome measures We measured disease activity scores (DAS) at each visit, then analysed therapeutic response and associated factors in a time-dependent fashion over 12?months. Results The median DAS4vESR of 4.46 at baseline decreased 12?weeks later by 24%, while the proportion with DAS4v???2.6 increased (p<0.01). DAS4v continued to decrease over 52?weeks. DAS4v reduction of at least ?0.45 at 4?weeks was predictive of DAS4v at 28 and 52?weeks. Female gender, current smoking, primary education and an interaction between baseline weight and C reactive protein (CRP) negatively impacted DAS4v reduction over 4 and 52?weeks. Time-varying effects of blood pressure, neutrophils, erythrocyte sedimentation rate and CRP also significantly influenced DAS4v over 52?weeks. Conclusions Time-dependent data suggest that the largest reduction of DAS4v to combination DMARDs occurs in the first month of therapy, and this predicts subsequent response. Variables known to impact long-term treatment response in RA also impacted early DAS4v response to combination DMARDs.

White, Douglas; Pahau, Helen; Duggan, Emily; Paul, Sanjoy; Thomas, Ranjeny

2013-01-01

267

Mechanical Response and Decomposition of Thermally Degraded Energetic Materials: Experiments and Model Simulations  

Microsoft Academic Search

We report progress of a continuing effort to characterize and simulate the response of energetic materials (EMs), primarily HMX-based, under conditions leading to cookoff. Our experiments include mechanical-effects testing of HMX and FIMX with binder at temperatures nearing decomposition thresholds. Additional experiments have focused on decomposition of these EMs under confinement, measuring evolution of gas products and observing the effect

MICHAEL J. KANESHIGE; ANITA M. RENLUND; ROBERT G. SCHMITT; GERALD W. WELLMAN

1999-01-01

268

Canonical Decomposition of Steerable Functions  

Microsoft Academic Search

This paper describes a general mathematical formulation for the problem of constructing steerable functions. The formulation is based on Lie group theory and is thus applicable to transformations which are Lie groups, such as, rotation, translation, scaling, and affine transformation. For one-parameter and Abelian multi-parameter Lie transformation groups, a canonical decomposition of all possible steerable functions, derived using the Jordan

Yacov Hel-or; Patrick C. Teo

1996-01-01

269

Thermal decomposition of energetic materials  

Microsoft Academic Search

The studies of thermal decomposition to identify mechanisms and quantify kinetic parameters are complex and its extrapolation to real scale could be not acceptable. Using an intermediate scale setup, three typical explosives, AN, PETN and RDX, with an inert material (silica sand) are submitted to fast heating rate. The experimental apparatus is based in a propane\\/air burner, a combustion chamber

Pedro A. Cardão; Jose´ C. Gois; Jose´ A. Campos

2000-01-01

270

Thermal Decomposition of Energetic Materials  

Microsoft Academic Search

The studies of thermal decomposition to identify mechanisms and quantify kinetic parameters are complex and extrapolation to real scale could not be acceptable. Using an intermediate scale setup, three typical explosives, AN, PETN and RDX, with an inert material (silica sand) were submitted to fast heating rate. The experimental apparatus is based in a propane\\/air burner, a combustion chamber and

P. Cardão; J. C. Gois; J. Campos

1999-01-01

271

The Thermal Decomposition Of Perfluoropropene.  

National Technical Information Service (NTIS)

The thermal decomposition of perfluoropropene (C3F6) was studied in a vycor reactor vessel over the temperature and initial pressure ranges 552-676C and 50-410 torr respectively. The order of the reaction with respect to C3F6 was found to be represented b...

R. A. Matula

1968-01-01

272

Accelerating matrix decomposition with replications  

Microsoft Academic Search

Matrix decomposition applications that involve large matrix operations can take advantage of the flexibility and adaptability of reconfigurable computing systems to improve performance. The benefits come from replication, which includes vertical replication and horizontal replication. If viewed on a space-time chart, vertical replication allows multiple computations executed in parallel, and horizontal replication renders multiple functions on the same piece of

Yi-gang Tai; Chia-tien Dan Lo; Kleanthis Psarris

2008-01-01

273

Scaling up through domain decomposition  

Microsoft Academic Search

In this article, we discuss domain decomposition parallel iterative solvers for highly heterogeneous problems of flow and transport in porous media. We are particularly interested in highly unstructured coefficient variation where standard periodic or stochastic homogenization theory is not applicable. When the smallest scale at which the coefficient varies is very small, it is often necessary to scale up the

Clemens Pechstein; Robert Scheichl

2009-01-01

274

Novel transgenic mouse models develop retinal changes associated with early diabetic retinopathy similar to those observed in rats with diabetes mellitus.  

PubMed

Retinal capillary pericyte degeneration has been linked to aldose reductase (AR) activity in diabetic retinopathy (DR). Since the development of DR in mice and rats has been reported to differ and that this may be linked to differences in retinal sorbitol levels, we have established new murine models of early onset diabetes mellitus as tools for investigating the role of AR in DR. Transgenic diabetic mouse models were developed by crossbreeding diabetic C57BL/6-Ins2(Akita)/J (AK) with transgenic C57BL mice expressing green fluorescent protein (GFP), human aldose reductase (hAR) or both in vascular tissues containing smooth muscle actin-? (SMAA). Changes in retinal sorbitol levels were determined by HPLC while changes of growth factors and signaling were investigated by Western Blots. Retinal vascular changes were quantitatively analyzed on elastase-digestion flat mounts. Results show that sorbitol levels were higher in neural retinas of diabetic AK-SMAA-GFP-hAR compared to AK-SMAA-GFP mice. AK-SMAA-GFP-hAR mice showed induction of the retinal growth factors VEGF, IGF-1, bFGF and TGF?, as well as signaling changes in P-Akt, P-SAPK/JNK, and P-44/42 MAPK. Increased loss of nuclei per capillary length and a significant increase in the percentage of acellular capillaries presented in 18 week old AK-SMAA-GFP-hAR mice. These changes are similar to those observed in streptozotocin-induced diabetic rats. Retinal changes in both mice and rats were prevented by inhibition of AR. These studies confirm that the increased expression of AR in mice results in the development of retinal changes associated with the early stages of DR that are similar to those observed in rats. PMID:24370601

Guo, Changmei; Zhang, Zifeng; Zhang, Peng; Makita, Jun; Kawada, Hiroyoshi; Blessing, Karen; Kador, Peter F

2014-02-01

275

The discrepancy between OH production rates deduced from radio and ultraviolet observations of comets. I - A comparative study of OH radio and UV observations of P/Halley 1986 III in late November and early December 1985  

NASA Astrophysics Data System (ADS)

OH UV and radio observations of P/Halley in late November and early December have been combined to determine the quenching radius, the total number of radicals in the coma, the OH lifetime, and the OH production rate. The convolution of the UV brightness profile by the radio antenna beams leads to a quenching radius of 65,000 + or - 15,000 km or 70,000 + or - 20,000 km, depending on the quenching model. A new method is proposed for determining the OH lifetime using the moments of the UV strip brightness distribution and of the radio line profile: the OH lifetime, reduced to 1 AU, is 110,000 + or - 30,000 s. and only weakly model-dependent. With these parameters, the UV and radio OH production rates in December 1985 are in reasonable agreement.

Gerard, E.

1990-04-01

276

Trade-Offs in Resource Allocation Among Moss Species Control Decomposition in Boreal Peatlands  

SciTech Connect

We separated the effects of plant species controls on decomposition rates from environmental controls in northern peatlands using a full factorial, reciprocal transplant experiment of eight dominant bryophytes in four distinct peatland types in boreal Alberta, Canada. Standard fractionation techniques as well as compound-specific pyrolysis molecular beam mass spectrometry were used to identify a biochemical mechanism underlying any interspecific differences in decomposition rates. We found that over a 3-year field incubation, individual moss species and not micro-environmental conditions controlled early stages of decomposition. Across species, Sphagnum mosses exhibited a trade-off in resource partitioning into metabolic and structural carbohydrates, a pattern that served as a strong predictor of litter decomposition. Decomposition rates showed a negative co-variation between species and their microtopographic position, as species that live in hummocks decomposed slowly but hummock microhabitats themselves corresponded to rapid decomposition rates. By forming litter that degrades slowly, hummock mosses appear to promote the maintenance of macropore structure in surface peat hummocks that aid in water retention. Many northern regions are experiencing rapid climate warming that is expected to accelerate the decomposition of large soil carbon pools stored within peatlands. However, our results suggest that some common peatland moss species form tissue that resists decomposition across a range of peatland environments, suggesting that moss resource allocation could stabilize peatland carbon losses under a changing climate.

Turetsky, M. R.; Crow, S. E.; Evans, R. J.; Vitt, D. H.; Wieder, R. K.

2008-01-01

277

Spectral Analysis on the Canonical Autoregressive Decomposition.  

National Technical Information Service (NTIS)

Time series modeling as the sum of an autoregressive (AR) process and sinusoids is proposed. When the AR model order is infinite, it is called Canonical Autoregressive Decomposition (CARD) and is equivalent to the Wold decomposition. Maximum likelihood es...

F. Santosa

1992-01-01

278

Thermal Decomposition Pathways in Nitramine Propellants.  

National Technical Information Service (NTIS)

We have investigated intermediates and products in the thermal decomposition of RDX vapor, using a variety of experimental microwave techniques previously employed in our laboratory in studies of pyrolysis decomposition of organic amines. We used microwav...

F. J. Lovas R. D. Suenram

1995-01-01

279

Thermal decomposition of some metal sulfates  

Microsoft Academic Search

Results are reported of detailed studies of the vaporization-decomposition of MgSOâ and CaSOâ carried out by means of the combined torsion and gravimetric Knudsen effusion method. A preliminary decomposition mechanism is discussed. (LK)

K. H. Lau; D. L. Hildebrand; D. Cubicciotti

1976-01-01

280

Generalized Helmholtz Decomposition and Static Electromagnetics.  

National Technical Information Service (NTIS)

The well-known decomposition of vector fields to solenoidal and irrotational parts, known as the Helmholtz decomposition, is generalized in terms of more general linear operators involving two arbitrary symmetric, positive-definite and complete (non-singu...

I. V. Lindell G. Dassios

2000-01-01

281

Radio-cesium accumulation during decomposition of leaf litter in a deciduous forest after the Fukushima NPP accident.  

NASA Astrophysics Data System (ADS)

Fukusima NPP accident contaminated vast area in eastern Japan with radio isotopes. Most of the area is covered by natural and plantation forest. The forest floor in deciduous forests, and canopy of evergreen forest were most contaminated by fall out. Radio-cesium is known to stay bioavailable in forest ecosystems for long time, and it is necessary to cut the cycling process to decontaminate the forest ecosystem. Ecological process to recycle radio-Cs in forest ecosystem should be studied to enhance decontamination of radio-Cs. Mushrooms show high concentration of Cs. Although mushroom biomass in a forest ecosystem is small, fungal mycelium in detritus and soil is large, thus fungi contain substantial amount of radio-Cs. It is well known that concentration of some nutrients, such as nitrogen and phosphorus, increase, whereas potassium decreases during the leaf litter decomposition. We observed radio-Cs concentration of leaf litter during decomposition on a forest floor where 134-Cs and 137-Cs of surface soil were 5,700, and 6,800 Bq/kg, respectively. We put 16 g (dry weight) of newly fallen mixed deciduous leaf litter (half of which was oak, Quercus serrata) into 25 cm x 25 cm litter bag (2 mm mesh size) in a deciduous forest about 50 km from Fukushima NPP. Fresh litter 137-Cs concentration was ca. 1,000 Bq/kg in December 2011. During the decomposition process on the forest floor, litter Cs increased exponentially and exceeded 10,000 Bq/kg after 6 months, indicating that Cs and K show contrasting dynamics during early decomposition phase. Increase in fungal biomass in the early stage of litter decomposition was observed. Therefore, this upward movement of Cs from humus and soil layer suggests fungal translocation of nutrients from outside of litter substrate. Retrieving the litter after 6 months can remove 18.0% of 134-Cs. Interaction between fungal species, grazing effect on fungi by fungivorous invertebrates will change the amount of translocation of radio-Cs from soil to decomposing litter.

Kaneko, Nobuhiro; Huang, Yao; Nakamori, Taizo; Tanaka, Yoichiro; Nonaka, Masanori

2013-04-01

282

In Situ Infrared Study of Catalytic Decomposition of NO  

SciTech Connect

The growing concerns for the environment and increasingly stringent standards for NO emission have presented a major challenge to control NO emmissions from electric utility plants and automobiles. Catalytic decomposition of NO is the most attractive approach for the control of NO emission for its simplicity. Successful development of an effective catalyst for NO decomposition will greatly decrease the equipment and operation cost of NO control. Due to lack of understanding of the mechanism of NO decomposition, efforts on the search of an effective catalyst have been unsuccesful. Scientific development of an effective catalyst requires fundamental understanding of the nature of active site, the rate-limiting step, and an approach to prolong the life of the catalyst. Research is proposed to study the reactivity of adsorbates for the direct NO decomposition and to investigate the feasibility of two novel approaches for improving catalyst activity and resistance to sintering. The first approach is the use of silanation to stabilize metal crystallites and supports for Cu-ZSM-5 and promoted Pt catalysts; the second is utilization of oxygen spillover and desorption to enhance NO decomposition activity. An innovative infrared reactor system will be used to observe and determine the dynamic behavior and the reactivity of adsorbates during NO decomposition, oxygen spillover, and silanation. A series of experiments including X-ray diffraction, temperature programmed desorption, temperature programmed reaction, X-ray photoelectron spectroscopy will be used to characterized the catalysts. The information obtained from this study will provide a scientific basis for developing an effective catalyst for the NO decomposition under practical flue gas conditions.

Cher-Dip Tan; Steven S.C. Chuang

1997-07-17

283

Perspectives on Pentaerythritol Tetranitrate (PETN) Decomposition  

Microsoft Academic Search

This report evaluates the large body of work involving the decomposition of PETN and identifies the major decomposition routes and byproducts. From these studies it becomes apparent that the PETN decomposition mechanisms and the resulting byproducts are primarily determined by the chemical environment. In the absence of water, PETN can decompose through the scission of the O-NO² bond resulting in

D Chambers; C Brackett; D O Sparkman

2002-01-01

284

Electrolytic decomposition of amaranth dyestuff using diamond electrodes  

Microsoft Academic Search

The electrolytic decomposition of an amaranth dyestuff solution using several combinations of electrodes with diamond and platinum is reported. It is observed that a portion of the amaranth is decomposed on the cathode surface while the other portion is decomposed to lower molecular weight components on the anode surface. The decolourizing rate is higher at diamond electrodes used as the

S. Hattori; M. Doi; E. Takahashi; T. Kurosu; M. Nara; S. Nakamatsu; Y. Nishiki; T. Furuta; M. Iida

2003-01-01

285

The (3P1) Mercury-Photosensitized Decomposition of Monogermane.  

National Technical Information Service (NTIS)

The Hg6(triplet-P1)-photosensitized decomposition of GeH4 appears to proceed by rupture of a Ge-H bond. Hydrogen, digermane, trigermane, tetragermane, and polymer were observed products. The H atoms formed in the primary process were not scavenged by 5% a...

Y. Rousseau G. J. Mains

1966-01-01

286

Convexity Rule for Shape Decomposition Based on Discrete Contour Evolution  

Microsoft Academic Search

We concentrate here on decomposition of 2D objects into mean- ingful parts of visual form ,o rvisual parts. It is a simple observation that convex parts of objects determine visual parts. However, the problem is that many significant visual parts are not convex, since a visual part may have concavities. We solve this problem by identify- ing convex parts at

Longin Jan Latecki; Rolf Lakämper

1999-01-01

287

Decomposition Mechanism and Decomposition Promoting Factors of Waste Hard Metal for Zinc Decomposition Process (ZDP)  

NASA Astrophysics Data System (ADS)

Decomposition promoting factors and decomposition mechanism in the zinc decomposition process of waste hard metals which are composed mostly of tungsten carbide and cobalt were evaluated. Zinc volatility amount was suppressed and zinc steam pressure was produced in the reaction graphite crucible inside an electric furnace for ZDP. Reaction was done for 2 hrs at 650 °C, which 100 % decomposed the waste hard metals that were over 30 mm thick. As for the separation-decomposition of waste hard metals, zinc melted alloy formed a liquid composed of a mixture of ?-?1 phase from the cobalt binder layer (reaction interface). The volume of reacted zone was expanded and the waste hard metal layer was decomposed-separated horizontally from the hard metal. Zinc used in the ZDP process was almost completely removed-collected by decantation and volatilization-collection process at 1000 °C. The small amount of zinc remaining in the tungsten carbide-cobalt powder which was completely decomposed was fully removed by using phosphate solution which had a slow cobalt dissolution speed.

Pee, J. H.; Kim, Y. J.; Kim, J. Y.; Seong, N. E.; Cho, W. S.; Kim, K. J.

2011-10-01

288

Crop residue decomposition in Minnesota biochar amended plots  

NASA Astrophysics Data System (ADS)

Impacts of biochar application at laboratory scales are routinely studied, but impacts of biochar application on decomposition of crop residues at field scales have not been widely addressed. The priming or hindrance of crop residue decomposition could have a cascading impact on soil processes, particularly those influencing nutrient availability. Our objectives were to evaluate biochar effects on field decomposition of crop residue, using plots that were amended with biochars made from different feedstocks and pyrolysis platforms prior to the start of this study. Litterbags containing wheat straw material were buried below the soil surface in a continuous-corn cropped field in plots that had received one of seven different biochar amendments or a non-charred wood pellet amendment 2.5 yr prior to start of this study. Litterbags were collected over the course of 14 weeks. Microbial biomass was assessed in treatment plots the previous fall. Though first-order decomposition rate constants were positively correlated to microbial biomass, neither parameter was statistically affected by biochar or wood-pellet treatments. The findings indicated only a residual of potentially positive and negative initial impacts of biochars on residue decomposition, which fit in line with established feedstock and pyrolysis influences. Though no significant impacts were observed with field-weathered biochars, effective soil management may yet have to account for repeat applications of biochar.

Weyers, S. L.; Spokas, K. A.

2014-02-01

289

Photofragmentation of closo-carboranes part 1: Energetics of decomposition.  

PubMed

The ionic fragmentation following B 1s and C 1s excitation of three isomeric carborane cage compounds [closo-dicarbadodecaboranes: orthocarborane (1,2-C2B10H12), metacarborane (1,7-C2B10H12), and paracarborane (1,12-C2B10H12)] is compared with the energetics of decomposition. The fragmentation yields for all three molecules are quite similar. Thermodynamic cycles are constructed for neutral and ionic species in an attempt to systemically characterize single-ion closo-carborane creation and fragmentation processes. Lower energy decomposition processes are favored. Among the ionic species, the photon-induced decomposition is dominated by BH+ and BH2(+) fragment loss. Changes in ion yield associated with core to bound excitations are observed. PMID:18327925

Feng, Danqin; Liu, Jing; Hitchcock, Adam P; Kilcoyne, A L David; Tyliszczak, Tolek; Riehs, Norman F; Rühl, Eckart; Bozek, John D; McIlroy, David; Dowben, Peter A

2008-04-17

290

Exsolution by spinodal decomposition in multicomponent mineral solutions  

PubMed Central

Phase separation in a three-component system that results from the uphill diffusion of chemical components is considered. The binary decomposition model of Cahn and Hilliard is generalized to account for the interdiffusion of several chemical components with considerably different diffusion constants. Thereafter the decomposition dynamics and the phase relations of the final system state are investigated by means of finite-element modeling. Examples from a hypothetical regular solution and from ternary feldspar are addressed. Special attention is given to situations in which different diffusivities affect decomposition dynamics and the final system states. Good qualitative agreement between our modeling and petrographic observations on exsolved feldspar is achieved. Our model explains systematic deviations from equilibrium element partitioning between the two phases exsolving from an initially homogeneous ternary feldspar during slow cooling.

Petrishcheva, E.; Abart, R.

2012-01-01

291

Isothermal Decomposition of Ferrite in a High-Nitrogen, Nickel-Free Duplex Stainless Steel  

NASA Astrophysics Data System (ADS)

The formation and crystallography of second phases during isothermal decomposition of ferrite (?) in a high-nitrogen, nickel-free duplex stainless steel was examined by means of transmission electron microscopy (TEM). At an early stage of aging, the decomposition of ? started along the ?/ ? phase boundaries where sigma ( ?) phase and secondary austenite ( ? 2) precipitated in the form of an alternating lamellar structure. The combined analyses based on the simulation of diffraction patterns and stereographic projection have shown that most of the ? phase was related to the ? 2 by the following relation: (111)_{? } allel (001)_{? } and [10bar{1}]_{? } allel [110]_{? } . The intergranular and intragranular precipitation of Cr2N with trigonal structure were identified, and the orientation relationships (ORs) with ? and ? matrix could be expressed as left( {110} right)_{? } allel left( {0001} right)_{{{text{Cr}}2 {text{N}}}} , left[ {bar{1}11} right]_{? } allel [bar{1}100]_{{{text{Cr}}2 {text{N}}}} ; (111)_{? } allel (0001)_{{{text{Cr}}2 {text{N}}}} , and left[ {bar{1}10} right]_{? } allel left[ {bar{1}100} right]_{{{text{Cr}}2 {text{N}}}} , respectively. The precipitation of intermetallic ? phase was also observed inside the ? matrix, and they obeyed the cube-on-cube OR with the ? matrix. Prolonged aging changed both the structure of matrix and the distribution of second phases. The ? 2, formed by decomposition of ?, became unstable because of the depletion of mainly N accompanied by the formation of Cr2N, and it transformed into martensite after subsequent cooling. As a result, the microstructure of the decomposed ? region was composed of three kinds of precipitates (intermetallic ?, ?, and Cr2N) embedded in lath martensite.

Lee, Tae-Ho; Ha, Heon-Young; Hwang, Byoungchul; Kim, Sung-Joon

2012-03-01

292

[Characteristics of the biochemical composition of plant litter at different stages of decomposition (according to thermal analysis data)].  

PubMed

The composition of samples of needles, leaves, sheaved cottongrass (Eriophorum vaginatum) tissues, and the L horizon of the forest floor of different degree of decomposition, isolated from the plant litter in southern taiga ecosystems, was studied by thermal analysis. It was established that plant litter decomposition is accompanied by structural changes in celluloses and that the decomposition rates of hemicellulose and structured cellulose vary at different stages of decomposition. The structural specificity and incongruent thermal decomposition of grass lignocellulose were observed in all samples of plant material. The rates at which the content of components of the plant litter decreased depended on the type and stage of decomposition of plant material. The decomposition rate of biochemical components tended to increase in better drained soils. PMID:18491564

Kosheleva, Iu P; Trofimov, S Ia

2008-01-01

293

Refining signal decomposition for GRETINA detectors  

NASA Astrophysics Data System (ADS)

The reconstruction of the original direction and energy of gamma rays through locating their interaction points in solid state detectors is a crucial evolving technology for nuclear physics, space science and homeland security. New arrays AGATA and GRETINA have been built for nuclear science based on highly segmented germanium crystals. The signal decomposition process fits the observed waveform from each crystal segment with a linear combination of pre-calculated basis signals. This process occurs on an event-by-event basis in real time to extract the position and energy of ?-ray interactions. The methodology for generating a basis of pulse shapes, varying according to the position of the charge generating interactions, is in place. Improvements in signal decomposition can be realized by better modeling the crystals. Specifically, a better understanding of the true impurity distributions, internal electric fields, and charge mobilities will lead to more reliable bases, more precise definition of the interaction points, and hence more reliable tracking. In this presentation we will cover the current state-of-the-art for basis generation and then discuss the sensitivity of the predicted pulse shapes when varying some key parameters.

Prasher, V. S.; Campbell, C. M.; Cromaz, M.; Crawford, H. L.; Wiens, A.; Lee, I. Y.; Macchiavelli, A. O.; Lister; Merchan, E.; Chowdhury, P.; Radford, D. C.

2013-04-01

294

Balancing domain decomposition for mixed finite elements  

SciTech Connect

The rate of convergence of the Balancing Domain Decomposition method applied to the mixed finite element discretization of second-order elliptic equations is analyzed. The Balancing Domain Decomposition method, introduced recently by Mandel, is a substructuring method that involves at each iteration the solution of a local problem with Dirichlet data, a local problem with Neumann data, and a {open_quotes}coarse grid{close_quotes} problem to propagate information globally and to insure the consistency of the Neumann problems. It is shown that the condition number grows at worst like the logarithm squared of the ratio of the subdomain size to the element size, in both two and three dimensions and for elements of arbitrary order. The bounds are uniform with respect to coefficient jumps of arbitrary order. The bounds are uniform with respect to coefficient jumps of arbitrary size between subdomains. The key component of this analysis is the demonstration of an equivalence between the norm induced by the bilinear form on the interface and the H{sup 1/2}-norm of an interpolant of the boundary data. Computational results from a message-passing parallel implementation on an INTEL-Delta machine demonstrate the scalability properties of the method and show almost optimal linear observed speed-up for up to 64 processors.

Cowsar, L.C.; Mandel, J.; Wheeler, M.F.

1995-07-01

295

Anisotropic Decomposition of Energetic Materials.  

NASA Astrophysics Data System (ADS)

Using a white x-ray synchrotron beam, we have dynamically studied radiation-induced decomposition in single crystalline PETN and TATB. By monitoring the integrated intensity of selected diffraction spots via a CCD x-ray camera as a function of time, we have found that the decomposition rate varies dramatically depending upon the orientation of the crystalline axes relative to polarized x-ray beam and for differing diffracting conditions (spots) within the same crystalline orientation. We suggest that this effect is due to Compton scattering of the polarized x-rays with electron clouds that is dependent upon their relative orientation. This novel effect may yield valuable insight regarding anisotropic detonation sensitivity in energetic materials such as PETN.

Pravica, Michael; Quine, Zachary; Romano, Edward; Bajar, Sean; Yulga, Brian; Yang, Wenge; Hooks, Daniel

2007-12-01

296

Anisotropic Decomposition of Energetic Materials  

SciTech Connect

Using a white x-ray synchrotron beam, we have dynamically studied radiation-induced decomposition in single crystalline PETN and TATB. By monitoring the integrated intensity of selected diffraction spots via a CCD x-ray camera as a function of time, we have found that the decomposition rate varies dramatically depending upon the orientation of the crystalline axes relative to polarized x-ray beam and for differing diffracting conditions (spots) within the same crystalline orientation. We suggest that this effect is due to Compton scattering of the polarized x-rays with electron clouds that is dependent upon their relative orientation. This novel effect may yield valuable insight regarding anisotropic detonation sensitivity in energetic materials such as PETN.

Pravica, Michael; Quine, Zachary; Romano, Edward; Bajar, Sean; Yulga, Brian; Yang, Wenge; Hooks, Daniel (UNLV); (CIW); (LANL)

2008-01-17

297

Anisotropic decomposition of energetic materials  

SciTech Connect

Using a white x-ray synchrotron beam, we have dynamically studied radiation-induced decomposition in single crystalline PETN and TATB. By monitoring the integrated intensity of selected diffraction spots via a CCD x-ray camera as a function of time, we have found that the decomposition rate varies dramatically depending upon the orientation of the crystalline axes relative to polarized x-ray beam and for differing diffracting conditions (spots) within the same crystalline orientation. We suggest that this effect is due to Compton scattering of the polarized x-rays with electron clouds that is dependent upon their relative orientation. This novel effect may yield valuable insight regarding anisotropic detonation sensitivity in energetic materials such as PETN.

Pravica, Michael; Quine, Zachary; Romano, Edward; Bajar, Sean; Yulga, Brian [High Pressure Science and Engineering Center and Department of Physics, University of Nevada Las Vegas, Las Vegas, NV USA, 89154-4002 (United States); Yang Wenge [HP-CAT, Advanced Photon Source, Argonne National Laboratory, Argonne, IL (United States); Hooks, Daniel [Dynamic Experimentation Division (DE-9), Los Alamo National Laboratory, Los Alamos, NM 87545 (United States)

2007-12-12

298

Spectral decomposition of broad-line agns and host galaxies  

SciTech Connect

Using an eigenspectrum decomposition technique, we separate the host galaxy from the broad line active galactic nucleus (AGN) in a set of 4666 spectra from the Sloan Digital Sky Survey (SDSS), from redshifts near zero up to about 0.75. The decomposition technique uses separate sets of galaxy and quasar eigenspectra to efficiently and reliably separate the AGN and host spectroscopic components. The technique accurately reproduces the host galaxy spectrum, its contributing fraction, and its classification. We show how the accuracy of the decomposition depends upon S/N, host galaxy fraction, and the galaxy class. Based on the eigencoefficients, the sample of SDSS broad-line AGN host galaxies spans a wide range of spectral types, but the distribution differs significantly from inactive galaxies. In particular, post-starburst activity appears to be much more common among AGN host galaxies. The luminosities of the hosts are much higher than expected for normal early-type galaxies, and their colors become increasingly bluer than early-type galaxies with increasing host luminosity. Most of the AGNs with detected hosts are emitting at between 1% and 10% of their estimated Eddington luminosities, but the sensitivity of the technique usually does not extend to the Eddington limit. There are mild correlations among the AGN and host galaxy eigencoefficients, possibly indicating a link between recent star formation and the onset of AGN activity. The catalog of spectral reconstruction parameters is available as an electronic table.

Vanden Berk, Daniel E.; Shen, Jiajian; /Penn State U., Astron. Astrophys.; Yip, Ching-Wa; /Pittsburgh U.; Schneider, Donald P.; /Penn State U., Astron. Astrophys.; Connolly, Andrew J.; /Pittsburgh U.; Burton, Ross E.; /Pittsburgh U. /Case Western Reserve U.; Jester, Sebastian; /Fermilab; Hall, Patrick B.; /York U., Canada; Szalay, Alex S.; /Johns Hopkins U.; Brinkmann, John; /Apache Point Observ.

2005-09-01

299

Decomposition Studies of Tetraphenylborate Slurries  

SciTech Connect

This report details the decomposition of aqueous (K,Na) slurries in concentrated salt solutions using a more complete candidate catalyst recipe, extended testing temperatures (40-70 degrees C) and test durations of approximately 1500 hours (9 weeks). This study uses recently developed High-Pressure Liquid Chromatography (HPLC) methods for analysis of tetraphenylborate (TPB-), triphenylborane (3PB) and diphenylborinic acid (2PB). All of the present tests involve non-radioactive simulants and do not include investigations of radiolysis effects.

Crawford, C.L. [Westinghouse Savannah River Company, AIKEN, SC (United States)

1997-05-06

300

A global HMX decomposition model  

Microsoft Academic Search

HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) decomposes by competing reaction pathways to form various condensed and gas-phase intermediate and final products. Gas formation is related to the development of nonuniform porosity and high specific surface areas prior to ignition in cookoff events. Such thermal damage enhances shock sensitivity and favors self-supported accelerated burning. The extent of HMX decomposition in highly confined cookoff experiments remains

1996-01-01

301

Metalization Patterns by Thermal Decomposition  

NASA Technical Reports Server (NTRS)

Metal interconnection pattern deposited on integrated circuit or solar cell economically by thermal decomposition of metallo-organic compound. In proposed process beam from laser or quartz lamp swept over substrate in required metalization pattern; wherever beam impinges on substrate, radiant heat decomposes compound, depositing metal. Process requires less costly equipment and less time than conventional metalization. Process readily adaptable to very-large-scale integrated (VLSI) circuits.

Gallagher, B. D.

1986-01-01

302

Steerable filters for early vision, image analysis, and wavelet decomposition  

Microsoft Academic Search

An efficient architecture is presented to synthesize filters of arbitrary orientations from linear combinations of basis filters, allowing one to adaptively `steer' a filter to any orientation, and to determine analytically the filter output as a function of orientation. The authors show how to design and steer filters, and present examples of their use in several tasks: the analysis of

W. T. Freeman; E. H. Adelson

1990-01-01

303

Climate sensitivity and macronutrient regulation of peat decomposition  

NASA Astrophysics Data System (ADS)

Organic soils act as vital global carbon stores maintained in northern latitudes by climate and nutrient limited rates of organic matter decomposition. Peatland decomposition rates are sensitive to climate change, however predicting the magnitude of the microbial respiratory response is complex due to unknown interactions between climate and substrate quality. The nutrient status of peatlands varies widely from mineral rich fens to nutrient poor ombrotrophic bogs, which have the potential to respond differently to climate driven changes in temperature and carbon (C) inputs. In this work we examine the links between peatland macronutrient C, phosphorus (P) and nitrogen (N) stoichiometry, microbial community structure and the microbial response to direct and indirect effects of climate change. Using total soil C:N and C:P ratios to define nutrient gradients in organic soils from Svalbard and Finland we investigated the interaction between the microbial response to temperature and nutrient limitation of decomposition. In organic rich soils from Svalbard we found there was a significant relationship between increasing temperature sensitivity of respiration and decreasing total soil P concentrations. Further investigation of the potential direct link between P limitation of decomposition and increased temperature sensitivity along a minerotrophic-ombroptrophic gradient in Finland was performed using multi-factorial P limitation assays. These showed that despite varying degrees of P limitation across four peatland soils there was no relationship between P limitation and increased temperature sensitivity of soil respiration. Throughout this study we found consistently high temperature sensitivity of decomposition in organic rich soils with Q10 values ranging between 2 to 4.5, indicating potentially higher vulnerability of these C stores to warming than is currently predicted using a globally invariant Q10. Following on from this we examined the interaction between peatland nutrient status and the potential for labile C substrates to stimulate (prime) decomposition of the peat organic matter. Using 13C labelled glucose and hemicellulose compounds we observed significant differences in the amount and rate of microbial substrate use between peats with differing nutrient status. Nutrient addition experiments were used with labelled C substrates to investigate the role of N and P limitation in enhancing or restricting priming effects. This is one of the first studies to use 13C substrates to examine potential priming effects in peat soil and it provides an insight into the importance of priming mechanisms in peat decomposition. This work explicitly links soil microbial responses to temperature and nutrient manipulations with microbial community structure allowing us to observe how microbial communities mediate soil C losses in peat soils. Disentangling the complex interactions between soil microbial community, C and nutrient limitation of decomposition is essential for predicting the vulnerability of different peatland ecosystems to climate driven changes.

Marshall, Rachel; Ostle, Nick; McNamara, Niall; Baggs, Elizabeth

2013-04-01

304

An observational longitudinal study to evaluate miction, defecation, and sexual function after radical hysterectomy with pelvic lymphadenectomy for early-stage cervical cancer.  

PubMed

The objective of this study was to evaluate the problems with miction, defecation, and sexuality after a radical hysterectomy with or without adjuvant radiotherapy for the treatment of cervical cancer stage I-IIA. This study included an observational longitudinal study of self-reported bladder, defecation, and sexual problems with a baseline score. Ninety-four women were included in the study. An age-matched control group consisted of 224 women. The patients showed significantly more negative effects on sexual function compared with both the controls and their situation before the treatment throughout 24 months of follow-up. The problems included less lubrication, a narrow and short vagina, senseless areas around the labia, dyspareunia, and sexual dissatisfaction. Up to 12 months after the treatment, the patients complained significantly more of little or no urge to urinate and diarrhea as compared with the controls. Adjuvant radiotherapy did not increase the risk of bladder dysfunction, colorectal motility disorders, and sexual functions. We conclude that a radical hysterectomy for the treatment of early-stage cervical carcinoma is associated with adverse effects mainly on sexual functioning. PMID:16803495

Pieterse, Q D; Maas, C P; ter Kuile, M M; Lowik, M; van Eijkeren, M A; Trimbos, J B M Z; Kenter, G G

2006-01-01

305

Leaf Litter Mixtures Alter Microbial Community Development: Mechanisms for Non-Additive Effects in Litter Decomposition  

PubMed Central

To what extent microbial community composition can explain variability in ecosystem processes remains an open question in ecology. Microbial decomposer communities can change during litter decomposition due to biotic interactions and shifting substrate availability. Though relative abundance of decomposers may change due to mixing leaf litter, linking these shifts to the non-additive patterns often recorded in mixed species litter decomposition rates has been elusive, and links community composition to ecosystem function. We extracted phospholipid fatty acids (PLFAs) from single species and mixed species leaf litterbags after 10 and 27 months of decomposition in a mixed conifer forest. Total PLFA concentrations were 70% higher on litter mixtures than single litter types after 10 months, but were only 20% higher after 27 months. Similarly, fungal-to-bacterial ratios differed between mixed and single litter types after 10 months of decomposition, but equalized over time. Microbial community composition, as indicated by principal components analyses, differed due to both litter mixing and stage of litter decomposition. PLFA biomarkers a15?0 and cy17?0, which indicate gram-positive and gram-negative bacteria respectively, in particular drove these shifts. Total PLFA correlated significantly with single litter mass loss early in decomposition but not at later stages. We conclude that litter mixing alters microbial community development, which can contribute to synergisms in litter decomposition. These findings advance our understanding of how changing forest biodiversity can alter microbial communities and the ecosystem processes they mediate.

Chapman, Samantha K.; Newman, Gregory S.; Hart, Stephen C.; Schweitzer, Jennifer A.; Koch, George W.

2013-01-01

306

Decomposition and hydrocarbon growth processes for hexadienes in nonpremixed flames  

SciTech Connect

Alkadienes are formed during the decomposition of alkanes and play a key role in the formation of aromatics due to their degree of unsaturation. The experiments in this paper examined the decomposition and hydrocarbon growth mechanisms of a wide range of hexadiene isomers in soot-forming nonpremixed flames. Specifically, C3 to C12 hydrocarbon concentrations were measured on the centerlines of atmospheric-pressure methane/air coflowing nonpremixed flames doped with 2000 ppm of 1,3-, 1,4-, 1,5-, and 2,4-hexadiene and 2-methyl-1,3-, 3-methyl-1,3-, 2-methyl-1,4-, 3-methyl-1,4-pentadiene, and 2,3-dimethyl-1,3-butadiene. The hexadiene decomposition rates and hydrocarbon product concentrations showed that the primary decomposition mechanism was unimolecular fission of C-C single bonds, whose fission produced allyl and other resonantly stabilized products. The one isomer that does not contain any of these bonds, 2,4-hexadiene, isomerized by a six-center mechanism to 1,3-hexadiene. These decomposition pathways differ from those that have been observed previously for propadiene and 1,3-butadiene, and these differences affect aromatic hydrocarbon formation. 1,5-Hexadiene and 2,3-dimethyl-1,3-butadiene produced significantly more C{sub 3}H{sub 4} and C{sub 4}H{sub 4} than the other isomers, but less benzene, which suggests that benzene formation pathways other than the conventional C3 + C3 and C4 + C2 pathways were important in most of the hexadiene-doped flames. The most likely additional mechanism is cyclization of highly unsaturated C5 decomposition products, followed by methyl addition to cyclopentadienyl radicals. (author)

McEnally, Charles S.; Pfefferle, Lisa D. [Department of Chemical Engineering and Center for Combustion Studies, Yale University, New Haven, CT 06520-8286 (United States)

2008-03-15

307

Fungi Associated with the Decomposition of the Black Rush Juncus Roemerianus in South Florida.  

National Technical Information Service (NTIS)

To determine what fungi are associated with the decomposition process and what affects certain environmental and sampling variables have on the observed fungal community structure, the fungi associated with Juncus roemerianus in a subtropical environment ...

J. W. Fell I. L. Hunter

1978-01-01

308

Implementation of Domain Decomposition and Data Decomposition Algorithms in RMC code  

NASA Astrophysics Data System (ADS)

The applications of Monte Carlo method in reactor physics analysis is somewhat restricted due to excessive memory demand in solving large-scale problems. Domain decomposition and data decomposition are two remedies. Memory demand in MC simulation is analyzed firstly. Domain decomposition and tally data decomposition algorithms separately are designed and implemented based on reactor Monte Carlo code RMC. Numerical tests are executed to evaluate performance of new algorithms respectively. Domain decomposition algorithm shows potentials to speed up MC simulation as a space parallel method. As for tally data decomposition algorithms, memory size is reduced obviously.

Liang, Jin'gang; Cai, Yun; Wang, Kan; She, Ding

2014-06-01

309

Time-resolved spectroscopic measurements of shock-wave induced decomposition in cyclotrimethylene trinitramine (RDX) crystals: anisotropic response.  

PubMed

Plate impact experiments on the (210), (100), and (111) planes were performed to examine the role of crystalline anisotropy on the shock-induced decomposition of cyclotrimethylenetrinitramine (RDX) crystals. Time-resolved emission spectroscopy was used to probe the decomposition of single crystals shocked to peak stresses ranging between 7 and 20 GPa. Emission produced by decomposition intermediates was analyzed in terms of induction time to emission, emission intensity, and the emission spectra shapes as a function of stress and time. Utilizing these features, we found that the shock-induced decomposition of RDX crystals exhibits considerable anisotropy. Crystals shocked on the (210) and (100) planes were more sensitive to decomposition than crystals shocked on the (111) plane. The possible sources of the observed anisotropy are discussed with regard to the inelastic deformation mechanisms of shocked RDX. Our results suggest that, despite the anisotropy observed for shock initiation, decomposition pathways for all three orientations are similar. PMID:20929273

Dang, Nhan C; Dreger, Zbigniew A; Gupta, Yogendra M; Hooks, Daniel E

2010-11-01

310

Symmetry-related decompositions of uncertainty  

NASA Astrophysics Data System (ADS)

In statistics, the sample mean and variance are intimately related to the symmetries of the full symmetric group describing all possible permutations of assignments of observations to sampling units. While those symmetries yield exactly two invariant subspaces (in a sense to be defined in the text) in correspondence to those summary statistics, the invariant subspaces associated with specific subgroups of the full symmetric group may then lead to much detailed decompositions of the experimental uncertainty. In the present chapter we discuss the symmetry-related summaries of data arising from dihedral experiments, specifically in the context of multinomial models for frequency counts in symbolic sequences. Special examples are given to dihedral summaries that can be potentially interpreted as measures of (molecular) chirality or handedness.

Viana, Marlos

2012-10-01

311

Downregulation of Early Ionotrophic Glutamate Receptor Subunit Developmental Expression as a Mechanism for Observed Plasticity Deficits Following Gestational Exposure to Benzo(a)pyrene  

PubMed Central

The focus of this study was to characterize the impact of gestational exposure to benzo(a)pyrene, [B(a)P] on modulation of glutamate receptor subunit expression that is critical for the maintenance of synaptic plasticity mechanisms during hippocampal or cortical development in offspring. Previous studies have demonstrated that hippocampal and/or cortical synaptic plasticity (as measured by long-term potentiation and S1-cortex spontaneous/evoked neuronal activity) and learning behavior (as measured by fixed-ratio performance operant testing) is significantly impaired in polycyclic aromatic or halogenated aromatic hydrocarbon-exposed offspring as compared to controls. These previous studies have also revealed that brain to body weight ratios are greater in exposed offspring relative to controls indicative of intrauterine growth retardation which has been shown to manifest as low birth weight in offspring. Recent epidemiological studies have identified an effect of prenatal exposure to airborne polycyclic aromatic hydrocarbons on neurodevelopment in the first 3 Years of life among inner-city children (Perera et al., 2006). The present study utilizes a well-characterized animal model to test the hypothesis that gestational exposure to B(a)P causes dysregulation of developmental ionotropic glutamate receptor subunit expression, namely the N-methyl-D-aspartate receptor (NMDAR) and ?-amino-3-hydroxy-5-methyl-4-isoxazole-propionate receptor (AMPAR) both critical to the expression of synaptic plasticity mechanisms. To mechanistically ascertain the basis of B(a)P-induced plasticity perturbations, timed pregnant Long-Evans rats were exposed in an oral subacute exposure regimen to 0, 25 and 150µg/kg BW B(a)P on gestation days 14–17. The first sub-hypothesis tested whether gestational exposure to B(a)P would result in significant disposition in offspring. The second sub-hypothesis tested whether gestational exposure to B(a)P would result in downregulation of early developmental expression of NMDA and AMPA receptor subunits in the hippocampus of offspring as well as in primary neuronal cultures. The results of these studies revealed significant: 1) disposition to the hippocampus and cortex, 2) down-regulation of developmental glutamate receptor mRNA and protein subunit expression and 3) voltage-dependent decreases in the amplitude of inward currents at negative potentials in B(a)P-treated cortical neuronal membranes. These results suggest that plasticity and behavioral deficits produced as a result of gestational B(a)P exposure are at least, in part, a result of down-regulation of early developmental glutamate receptor subunit expression and function at a time when excitatory synapses are being formed for the first time in the developing central nervous system. The results also predict that in B(a)P-exposed offspring with reduced early glutamate receptor subunit expression, a parallel deficit in behaviors that depend on normal hippocampal or cortical functioning will be observed and that these deficits will be present throughout life.

Brown, La'Nissa A.; Khoshbouei, Habibeh; Goodwin, J. Shawn; Irvin-Wilson, Charletha V.; Ramesh, Aramandla; Sheng, Liu; McCallister, Monique M.; Jiang, George C. T.; Aschner, Michael; Hood, Darryl B.

2007-01-01

312

Direct and indirect effects of UV-B exposure on litter decomposition: a meta-analysis.  

PubMed

Ultraviolet-B (UV-B) exposure in the course of litter decomposition may have a direct effect on decomposition rates via changing states of photodegradation or decomposer constitution in litter while UV-B exposure during growth periods may alter chemical compositions and physical properties of plants. Consequently, these changes will indirectly affect subsequent litter decomposition processes in soil. Although studies are available on both the positive and negative effects (including no observable effects) of UV-B exposure on litter decomposition, a comprehensive analysis leading to an adequate understanding remains unresolved. Using data from 93 studies across six biomes, this introductory meta-analysis found that elevated UV-B directly increased litter decomposition rates by 7% and indirectly by 12% while attenuated UV-B directly decreased litter decomposition rates by 23% and indirectly increased litter decomposition rates by 7%. However, neither positive nor negative effects were statistically significant. Woody plant litter decomposition seemed more sensitive to UV-B than herbaceous plant litter except under conditions of indirect effects of elevated UV-B. Furthermore, levels of UV-B intensity significantly affected litter decomposition response to UV-B (P<0.05). UV-B effects on litter decomposition were to a large degree compounded by climatic factors (e.g., MAP and MAT) (P<0.05) and litter chemistry (e.g., lignin content) (P<0.01). Results suggest these factors likely have a bearing on masking the important role of UV-B on litter decomposition. No significant differences in UV-B effects on litter decomposition were found between study types (field experiment vs. laboratory incubation), litter forms (leaf vs. needle), and decay duration. Indirect effects of elevated UV-B on litter decomposition significantly increased with decay duration (P<0.001). Additionally, relatively small changes in UV-B exposure intensity (30%) had significant direct effects on litter decomposition (P<0.05). The intent of this meta-analysis was to improve our understanding of the overall effects of UV-B on litter decomposition. PMID:23818993

Song, Xinzhang; Peng, Changhui; Jiang, Hong; Zhu, Qiuan; Wang, Weifeng

2013-01-01

313

Microstructure and X-Ray Study of Preferentially Oriented SnO2 Thin Film Prepared by Pyrohydrolytic Decomposition  

NASA Astrophysics Data System (ADS)

Preferentially oriented SnO2 thin films were prepared by pyrohydrolytic decomposition onto a glass substrate along the direction of flux flow. The obtained films were oriented in [200] and then [002] directions along the direction of flow. To reveal the orientation mechanism from the initial stage of growth, [200]-oriented SnO2 thin film was prepared on a chemically stable GaAs single crystal. The successive growth structure of the thin film on the substrate was accurately observed and characterized using HR-AEM (high-resolution analytical electron microscopy). A layer of nuclei about 50 Å in width was observed between the GaAs substrate and the oriented overgrown layer. It is suggested that such preferential nucleation occurs from an early stage of growth, and is strongly dependent on supersaturation of the flux flowing along the substrate.

Fujimoto, Masayuki; Urano, Tetsuya; Murai, Syunji; Nishi, Yuuji

1989-12-01

314

Decomposition-Based Decision Making for Aerospace Vehicle Design  

NASA Technical Reports Server (NTRS)

Most practical engineering systems design problems have multiple and conflicting objectives. Furthermore, the satisfactory attainment level for each objective ( requirement ) is likely uncertain early in the design process. Systems with long design cycle times will exhibit more of this uncertainty throughout the design process. This is further complicated if the system is expected to perform for a relatively long period of time, as now it will need to grow as new requirements are identified and new technologies are introduced. These points identify a need for a systems design technique that enables decision making amongst multiple objectives in the presence of uncertainty. Traditional design techniques deal with a single objective or a small number of objectives that are often aggregates of the overarching goals sought through the generation of a new system. Other requirements, although uncertain, are viewed as static constraints to this single or multiple objective optimization problem. With either of these formulations, enabling tradeoffs between the requirements, objectives, or combinations thereof is a slow, serial process that becomes increasingly complex as more criteria are added. This research proposal outlines a technique that attempts to address these and other idiosyncrasies associated with modern aerospace systems design. The proposed formulation first recasts systems design into a multiple criteria decision making problem. The now multiple objectives are decomposed to discover the critical characteristics of the objective space. Tradeoffs between the objectives are considered amongst these critical characteristics by comparison to a probabilistic ideal tradeoff solution. The proposed formulation represents a radical departure from traditional methods. A pitfall of this technique is in the validation of the solution: in a multi-objective sense, how can a decision maker justify a choice between non-dominated alternatives? A series of examples help the reader to observe how this technique can be applied to aerospace systems design and compare the results of this so-called Decomposition-Based Decision Making to more traditional design approaches.

Borer, Nicholas K.; Mavris, DImitri N.

2005-01-01

315

Conductimetric determination of decomposition of silicate melts  

NASA Technical Reports Server (NTRS)

A description of a procedure is given to detect decomposition of silicate systems in the liquid state by conductivity measurements. Onset of decomposition can be determined from the temperature curves of resistances measured on two pairs of electrodes, one above the other. Degree of decomposition can be estimated from temperature and concentration dependency of conductivity of phase boundaries. This procedure was tested with systems PbO-B2O3 and PbO-B2O3-SiO2.

Kroeger, C.; Lieck, K.

1986-01-01

316

Linking early Earth magma ocean crystallization and overturn with observed large low-shear-velocity provinces (LLSVPs) and short-lived radioisotopic measurements in Archean rocks  

NASA Astrophysics Data System (ADS)

Motivated by the well-characterized discrepancy between measurements of 142Nd in chondrites and those in Earth rocks (e.g.,[1][2]) in addition to recent measurements of Archean rocks with anomalous 142Nd and 182W (e.g.,[3][4][5]), we model the crystallization and overturn of a terrestrial chondritic magma ocean, and track the isotopic reservoirs that may result. Following magma ocean solidification, solid-state overturn occurs because solidification produces a gravitationally unstable configuration where the last cumulates to solidify are densest and also enriched in incompatible elements. As suggested by [1][2], these originally shallow cumulates that, following overturn, would now reside near the core-mantle boundary are tantalizing targets for the hypothesized hidden reservoir(s) of incompatible elements. These last, dense, enriched cumulates may have evolved negative 142Nd and 182W isotopic anomalies, while cumulates that form earlier and deeper in the magma ocean would likely be poor in incompatible elements and have evolved complementary positive isotopic anomalies. Because crystal - liquid partition coefficients of Sm, Nd, Hf, and W in nucleating mantle phases are poorly constrained and vary over orders of magnitude, we use a Monte Carlo approach to cover the parameter space of reported partition coefficients. Although data are limited, Archean rocks appear to show a non-linear trend between age and 142Nd and 182W, suggesting inefficient heterogeneous mixing of some of the early enriched reservoir (EER or late stage cumulates) back into the early depleted reservoir (EDR or deeper cumulates) during or after overturn, also first suggested by [1][2]. To account for this, we model various mixing scenarios using post-overturn mantle stratigraphy. Additionally, because 142Nd and 182W are decay products of short-lived radioisotopes, the timing of magma ocean crystallization is critical to producing a modern day mantle consistent with measured compositions. We therefore iterate through time to determine the statistically most likely time of the last major mantle-melting event. Consistent with [2], we argue that the EER is not hidden but is instead the seismologically observed large low-shear-velocity provinces (LLSVPs), or the D'' region, and the ultra low velocity zones (ULVZs) are dense, iron-rich silicon-poor melts of the LLSVPs. Given this, the isotopic reservoirs produced by our models must mix such that the EER remaining after mixing is the same volume as the LLSVPs, or 2% of the mantle (e.g., [6][7]). Approximately two-thirds our run results are "successful" given known partition coefficients, and so our results suggest that this model is viable: magma ocean fractional solidification can produce mantle reservoirs consistent with isotopic compositions observed in some rocks, and can produce a dense lower mantle layer consistent in longevity and volume to the LLSVPs. [1]Boyet and Carlson,2005,Science,309(5743),576-81.[2]Carlson and Boyet,2008,Phil. Trans. R. Soc. A,366(1883),4077-103. [3]Willbold et al.,2011,Nature,477(7363), 195-8. [4]Touboul et al.,2012,Science,335(6072),1065-9. [5]Rizo et al.,Nature,491(7422),96-100. [6]Burke et al.,2008,EPSL,265(1-2),49-60. [7]Hernlund and Houser,2008,EPSL,265(3-4),423-37.

Brown, S. M.; Elkins-Tanton, L. T.; Walker, R. J.

2013-12-01

317

El Mayor-Cucapah (Mw 7.2) earthquake: Early near-field postseismic deformation from InSAR and GPS observations  

NASA Astrophysics Data System (ADS)

Mayor-Cucapah earthquake occurred on 4 April 2010 in northeastern Baja California just south of the U.S.-Mexico border. The earthquake ruptured several previously mapped faults, as well as some unidentified ones, including the Pescadores, Borrego, Paso Inferior and Paso Superior faults in the Sierra Cucapah, and the Indiviso fault in the Mexicali Valley and Colorado River Delta. We conducted several Global Positioning System (GPS) campaign surveys of preexisting and newly established benchmarks within 30 km of the earthquake rupture. Most of the benchmarks were occupied within days after the earthquake, allowing us to capture the very early postseismic transient motions. The GPS data show postseismic displacements in the same direction as the coseismic displacements; time series indicate a gradual decay in postseismic velocities with characteristic time scales of 66 ± 9 days and 20 ± 3 days, assuming exponential and logarithmic decay, respectively. We also analyzed interferometric synthetic aperture radar (InSAR) data from the Envisat and ALOS satellites. The main deformation features seen in the line-of-sight displacement maps indicate subsidence concentrated in the southern and northern parts of the main rupture, in particular at the Indiviso fault, at the Laguna Salada basin, and at the Paso Superior fault. We show that the near-field GPS and InSAR observations over a time period of 5 months after the earthquake can be explained by a combination of afterslip, fault zone contraction, and a possible minor contribution of poroelastic rebound. Far-field data require an additional mechanism, most likely viscoelastic relaxation in the ductile substrate.

Gonzalez-Ortega, Alejandro; Fialko, Yuri; Sandwell, David; Alejandro Nava-Pichardo, F.; Fletcher, John; Gonzalez-Garcia, Javier; Lipovsky, Brad; Floyd, Michael; Funning, Gareth

2014-02-01

318

Impact of radiotherapy technique on the outcome of early breast cancer treated with conservative surgery: A multicenter observational study on 1,176 patients  

SciTech Connect

Purpose: To quantify the impact of radiotherapy technique on cosmetic outcome and on 5-year local control rate of early breast cancer treated with conservative surgery and adjuvant radiation. Methods and MaterialsPurpose: A total of 1,176 patients irradiated to the breast in 1997 were entered by eight centers into a prospective, observational study. Surgical procedure was quadrantectomy in 97% of patients, with axillary dissection performed in 96%; pT-stage was T1 in 81% and T2 in 19% of cases; pN-stage was N0 in 71%, N + (1-3) in 21%, and N + (>3) in 8% of cases. An immobilization device was used in 17% of patients; external contour-based and computed tomography-based treatment planning were performed in 20% and 72% of cases, respectively; 37% of patients were treated with a telecobalt unit and 63% with a linear accelerator; portal verification was used in 55% of patients; a boost dose to the tumor bed was delivered in 60% of cases. Results: With a median follow-up of 6.2 years, local, regional, and distant control rates at 5 years are 98%, 99%, and 92%, respectively. Use of less sophisticated treatment technique was associated with a less favorable cosmetic outcome. Local control was comparable between centers despite substantial technical differences. In a multivariate analysis including clinical and technical factors, only older age and prescription of medical adjuvant treatment significantly predicted for better local control, whereas use of portal verification was of borderline significance. Conclusions: Radiation technical factors impacted negatively on cosmetic outcome, but had relatively small effects on local control compared with other clinical factors.

Palazzi, Mauro [Istituto Nazionale Tumori, Milan (Italy)]. E-mail: mauro.palazzi@istitutotumori.mi.it; Tomatis, Stefano [Istituto Nazionale Tumori, Milan (Italy); Valli, Maria Carla [Ospedale S. Anna, Como (Italy); Guzzetti, Renata [Ospedali Riuniti, Bergamo (Italy); Tonoli, Sandro [Istituto del Radio, University of Brescia, Brescia (Italy); Bertoni, Filippo [Istituto del Radio, University of Brescia, Brescia (Italy); Magrini, Stefano Maria [Istituto del Radio, University of Brescia, Brescia (Italy); Meregalli, Sofia [Ospedale S. Gerardo, Monza (Italy); Asnaghi, Diego [Ospedale Ca' Granda Niguarda, Milan (Italy); Arienti, Virginia [Ospedale Ca' Granda Niguarda, Milan (Italy); Pradella, Renato [Ospedale C. Poma, Mantova (Italy); Cafaro, Ines [Ospedale Civile, Cremona (Italy)

2006-08-01

319

Early fluid loading in acute respiratory distress syndrome with septic shock deteriorates lung aeration without impairing arterial oxygenation: a lung ultrasound observational study  

PubMed Central

Introduction The study was designed to assess the impact of fluid loading on lung aeration, oxygenation and hemodynamics in patients with septic shock and acute respiratory distress syndrome (ARDS). Methods During a 1-year period, a prospective observational study was performed in 32 patients with septic shock and ARDS. Cardiorespiratory parameters were measured using Swan Ganz (n?=?29) or PiCCO catheters (n?=?3). Lung aeration and regional pulmonary blood flows were measured using bedside transthoracic ultrasound. Measurements were performed before (T0), at the end of volume expansion (T1) and 40 minutes later (T2), consisting of 1-L of saline over 30 minutes during the first 48 h following onset of septic shock and ARDS. Results Lung ultrasound score increased by 23% at T2, from 13 at baseline to 16 (P?Early fluid loading transitorily improves hemodynamics and oxygenation and worsens lung aeration. Aeration changes can be detected at the bedside by transthoracic lung ultrasound, which may serve as a safeguard against excessive fluid loading.

2014-01-01

320

Stellar Populations of Lyman Break Galaxies at z approx. to 1-3 in the HST/WFC3 Early Release Science Observations  

NASA Technical Reports Server (NTRS)

We analyze the spectral energy distributions (SEDs) of Lyman break galaxies . (LBGs) at z approx = 1-3 selected using the Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) UVIS channel filters. These HST /WFC3 obse,rvations cover about 50 arcmin2 in the GOODS-South field as a part of the WFC3 Early Release Science program. These LBGs at z approx = 1-3 are selected using dropout selection criteria similar to high redshift LBGs. The deep multi-band photometry in this field is used to identify best-fit SED models, from which we infer the following results: (1) the photometric redshift estimate of these dropout selected LBGs is accurate to within few percent; (2) the UV spectral slope f3 is redder than at high redshift (z > 3), where LBGs are less dusty; (3) on average, LBGs at .z approx = 1-3 are massive, dustier and more highly star-forming, compared to LBGs at higher redshifts with similar luminosities, though their median values are similar within 1a uncertainties. This could imply that identical dropout selection technique, at all. redshifts, find physically similar galaxies; and (4) the stellar masses of these LBGs are directly proportional to their UV luminosities with a logarithmic slope of approx 0.46, and star-formation rates are proportional to their stellar masses with a logarithmic slope of approx 0.90. These relations hold true - within luminosities probed in this study - for LBGs from z approx = 1.5 to 5. The star-forming galaxies selected using other color-based techniques show similar correlations at z approx = 2, but to avoid any selection biases, and for direct comparison with LBGs at z > 3, a true Lyman break selection at z approx = 2 is essential. The future HST UV surveys,. both wider and deeper, covering a large luminosity range are important to better understand LBG properties, and their evolution.

Hathi, N. P.; Cohen, S. H.; Ryan, R. E., Jr.; Finkelstein, S. L.; McCarthy, P. J.; Windhorst, R. A.; Yan, H.; Koekemoer, A. M.; Rutkowski, M. J.; OConnell, R. W.; Straughn, A. N.; Balick, B.; Bond, H. E.; Calzetti, D.; Disney, M. J.; Dopita, M. A.; Frogel, Jay A.; Hall, D. N. B.; Holtzman, J. A.; Kimble, R. A.; Paresce, F.; Saha, A.; Silk, J. I.; Tauger, J. T.; Young, E. T.

2012-01-01

321

SPECTROSCOPIC OBSERVATIONS OF SN 2012fr: A LUMINOUS, NORMAL TYPE Ia SUPERNOVA WITH EARLY HIGH-VELOCITY FEATURES AND A LATE VELOCITY PLATEAU  

SciTech Connect

We present 65 optical spectra of the Type Ia SN 2012fr, 33 of which were obtained before maximum light. At early times, SN 2012fr shows clear evidence of a high-velocity feature (HVF) in the Si II {lambda}6355 line that can be cleanly decoupled from the lower velocity ''photospheric'' component. This Si II {lambda}6355 HVF fades by phase -5; subsequently, the photospheric component exhibits a very narrow velocity width and remains at a nearly constant velocity of {approx}12,000 km s{sup -1} until at least five weeks after maximum brightness. The Ca II infrared triplet exhibits similar evidence for both a photospheric component at v Almost-Equal-To 12,000 km s{sup -1} with narrow line width and long velocity plateau, as well as an HVF beginning at v Almost-Equal-To 31,000 km s{sup -1} two weeks before maximum. SN 2012fr resides on the border between the ''shallow silicon'' and ''core-normal'' subclasses in the Branch et al. classification scheme, and on the border between normal and high-velocity Type Ia supernovae (SNe Ia) in the Wang et al. system. Though it is a clear member of the ''low velocity gradient'' group of SNe Ia and exhibits a very slow light-curve decline, it shows key dissimilarities with the overluminous SN 1991T or SN 1999aa subclasses of SNe Ia. SN 2012fr represents a well-observed SN Ia at the luminous end of the normal SN Ia distribution and a key transitional event between nominal spectroscopic subclasses of SNe Ia.

Childress, M. J.; Scalzo, R. A.; Sim, S. A.; Tucker, B. E.; Yuan, F.; Schmidt, B. P. [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia); Cenko, S. B.; Filippenko, A. V. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Silverman, J. M. [Department of Astronomy, University of Texas, Austin, TX 78712-0259 (United States); Contreras, C.; Hsiao, E. Y.; Phillips, M.; Morrell, N. [Las Campanas Observatory, Carnegie Observatories, Casilla 601, La Serena (Chile); Jha, S. W.; McCully, C. [Department of Physics and Astronomy, Rutgers, State University of New Jersey, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Anderson, J. P.; De Jaeger, T.; Forster, F. [Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago (Chile); Benetti, S. [INAF Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, I-35122 Padova (Italy); Bufano, F., E-mail: mjc@mso.anu.edu.au [Departamento de Ciencias Fisicas, Universidad Andres Bello, Avda. Republica 252, Santiago (Chile); and others

2013-06-10

322

APEX/SABOCA observations of small-scale structure of infrared-dark clouds . I. Early evolutionary stages of star-forming cores  

NASA Astrophysics Data System (ADS)

Infrared-dark clouds (IRDCs) harbor the early phases of cluster and high-mass star formation and are comprised of cold (~20 K), dense (n > 104 cm-3) gas. The spectral energy distribution (SED) of IRDCs is dominated by the far-infrared and millimeter wavelength regime, and our initial Herschel study examined IRDCs at the peak of the SED with high angular resolution. Here we present a follow-up study using the SABOCA instrument on APEX which delivers 7.8? angular resolution at 350 ?m, matching the resolution we achieved with Herschel/PACS, and allowing us to characterize substructure on ~0.1 pc scales. Our sample of 11 nearby IRDCs are a mix of filamentary and clumpy morphologies, and the filamentary clouds show significant hierarchical structure, while the clumpy IRDCs exhibit little hierarchical structure. All IRDCs, regardless of morphology, have about 14% of their total mass in small scale core-like structures which roughly follow a trend of constant volume density over all size scales. Out of the 89 protostellar cores we identified in this sample with Herschel, we recover 40 of the brightest and re-fit their SEDs and find their properties agree fairly well with our previous estimates (? T ? ~ 19 K). We detect a new population of "cold cores" which have no 70 ?m counterpart, but are 100 and 160 ?m-bright, with colder temperatures (? T ? ~ 16 K). This latter population, along with SABOCA-only detections, are predominantly low-mass objects, but their evolutionary diagnostics are consistent with the earliest starless or prestellar phase of cores in IRDCs. Based on observations carried out with the Atacama Pathfinder Experiment (APEX). APEX is a collaboration between Max Planck Institut für Radioastronomie (MPIfR), Onsala Space Observatory (OSO), and the European Southern Observatory (ESO).Appendices are available in electronic form at http://www.aanda.org

Ragan, Sarah E.; Henning, Thomas; Beuther, Henrik

2013-11-01

323

Spectroscopic Observations of SN 2012fr: A Luminous, Normal Type Ia Supernova with Early High-velocity Features and a Late Velocity Plateau  

NASA Astrophysics Data System (ADS)

We present 65 optical spectra of the Type Ia SN 2012fr, 33 of which were obtained before maximum light. At early times, SN 2012fr shows clear evidence of a high-velocity feature (HVF) in the Si II ?6355 line that can be cleanly decoupled from the lower velocity "photospheric" component. This Si II ?6355 HVF fades by phase -5 subsequently, the photospheric component exhibits a very narrow velocity width and remains at a nearly constant velocity of ~12,000 km s-1 until at least five weeks after maximum brightness. The Ca II infrared triplet exhibits similar evidence for both a photospheric component at v ? 12,000 km s-1 with narrow line width and long velocity plateau, as well as an HVF beginning at v ? 31,000 km s-1 two weeks before maximum. SN 2012fr resides on the border between the "shallow silicon" and "core-normal" subclasses in the Branch et al. classification scheme, and on the border between normal and high-velocity Type Ia supernovae (SNe Ia) in the Wang et al. system. Though it is a clear member of the "low velocity gradient" group of SNe Ia and exhibits a very slow light-curve decline, it shows key dissimilarities with the overluminous SN 1991T or SN 1999aa subclasses of SNe Ia. SN 2012fr represents a well-observed SN Ia at the luminous end of the normal SN Ia distribution and a key transitional event between nominal spectroscopic subclasses of SNe Ia.

Childress, M. J.; Scalzo, R. A.; Sim, S. A.; Tucker, B. E.; Yuan, F.; Schmidt, B. P.; Cenko, S. B.; Silverman, J. M.; Contreras, C.; Hsiao, E. Y.; Phillips, M.; Morrell, N.; Jha, S. W.; McCully, C.; Filippenko, A. V.; Anderson, J. P.; Benetti, S.; Bufano, F.; de Jaeger, T.; Forster, F.; Gal-Yam, A.; Le Guillou, L.; Maguire, K.; Maund, J.; Mazzali, P. A.; Pignata, G.; Smartt, S.; Spyromilio, J.; Sullivan, M.; Taddia, F.; Valenti, S.; Bayliss, D. D. R.; Bessell, M.; Blanc, G. A.; Carson, D. J.; Clubb, K. I.; de Burgh-Day, C.; Desjardins, T. D.; Fang, J. J.; Fox, O. D.; Gates, E. L.; Ho, I.-T.; Keller, S.; Kelly, P. L.; Lidman, C.; Loaring, N. S.; Mould, J. R.; Owers, M.; Ozbilgen, S.; Pei, L.; Pickering, T.; Pracy, M. B.; Rich, J. A.; Schaefer, B. E.; Scott, N.; Stritzinger, M.; Vogt, F. P. A.; Zhou, G.

2013-06-01

324

Outpatient management of severe early OHSS by administration of GnRH antagonist in the luteal phase: an observational cohort study  

PubMed Central

Background Management of established severe OHSS requires prolonged hospitalization, occasionally in intensive care units, accompanied by multiple ascites punctures, correction of intravascular fluid volume and electrolyte imbalance. The aim of the present study was to evaluate whether it is feasible to manage women with severe OHSS as outpatients by treating them with GnRH antagonists in the luteal phase. Methods This is a single-centre, prospective, observational, cohort study. Forty patients diagnosed with severe OHSS, five days post oocyte retrieval, were managed as outpatients after administration of GnRH antagonist (0.25?mg) daily from days 5 to 8 post oocyte retrieval, combined with cryopreservation of all embryos. The primary outcome measure was the proportion of patients with severe OHSS, in whom outpatient management was not feasible. Results 11.3% (95% CI 8.3%-15.0%) of patients (40/353) developed severe early OHSS. None of the 40 patients required hospitalization following luteal antagonist administration and embryo cryopreservation. Ovarian volume, ascites, hematocrit, WBC, serum oestradiol and progesterone decreased significantly (P?

2012-01-01

325

Separable States with Unique Decompositions  

NASA Astrophysics Data System (ADS)

We search for faces of the convex set consisting of all separable states, which are affinely isomorphic to simplices, to get separable states with unique decompositions. In the two-qutrit case, we found that six product vectors spanning a five dimensional space give rise to a face isomorphic to the 5-dimensional simplex with six vertices, under a suitable linear independence assumption. If the partial conjugates of six product vectors also span a 5-dimensional space, then this face is inscribed in the face for PPT states whose boundary shares the fifteen 3-simplices on the boundary of the 5-simplex. The remaining boundary points consist of PPT entangled edge states of rank four. We also show that every edge state of rank four arises in this way. If the partial conjugates of the above six product vectors span a 6-dimensional space then we have a face isomorphic to 5-simplex, whose interior consists of separable states with unique decompositions, but with non-symmetric ranks. We also construct a face isomorphic to the 9-simplex. As applications, we give answers to questions in the literature Chen and Djokovi? (J Math Phys 54:022201, 2013) and Chen and Djokovi? (Commun Math Phys 323:241-284, 2013), and construct 3 ? 3PPT states of type (9,5). For the qubit-qudit cases with d ? 3, we also show that ( d + 1)-dimensional subspaces give rise to faces isomorphic to the d-simplices, in most cases.

Ha, Kil-Chan; Kye, Seung-Hyeok

2014-05-01

326

Reaction sequence and kinetics of uranium nitride decomposition.  

PubMed

The reaction mechanism and kinetics of the thermal decomposition of uranium dinitride/uranium sesquinitride to uranium mononitride under inert atmosphere at elevated temperature were studied. An increase in the lattice parameter of the UN(2)/alpha-U(2)N(3) phase was observed as the reaction temperature increased, corresponding to a continuous removal of nitrogen. Electron density calculations for these two compounds using XRD powder patterns of the samples utilizing charge-flipping technique were performed for the first time to visualize the decrease in nitrogen level as a function of temperature. Complete decomposition of UN(2) into alpha-U(2)N(3) at 675 degrees C and the UN formation after a partial decomposition of alpha-U(2)N(3) at 975 degrees C were also identified in this study. The activation energy for the decomposition of the UN(2)/alpha-U(2)N(3) phase into UN, 423.8 +/- 0.3 kJ/mol (101.3 kcal/mol), was determined under an inert argon atmosphere and is reported here experimentally for the first time. PMID:19845318

Silva, G W Chinthaka; Yeamans, Charles B; Sattelberger, Alfred P; Hartmann, Thomas; Cerefice, Gary S; Czerwinski, Kenneth R

2009-11-16

327

Plasma Catalysis of Methane Decomposition in Pulse Microwave Discharge  

NASA Astrophysics Data System (ADS)

Investigation of plasma catalysis effects in various chemical reactions, such as SO2 and hydrocarbons oxidation, ammonia and nitrogen oxides synthesis, has been of interest for many decades. Present work describes the first experimental observation and theoretical analysis of plasma catalysis effects in the case of endothermic methane decomposition into molecular hydrogen and carbon black. Process energy requirements are coverd mainly by low potential gas thermal energy while plasma is used for acceleration of chemical reactions via active species generation. The experiments were done as follows: (i) methane was preheated in a conventional heat exchanger up to about 40-65 ^oC where thermal methane decomposition is limited by process kinetics, (ii) methane was passed through a non-equilibrium pulse microwave discharge (9.04 GHz, pulse duration 1 ?s). Experiments have shown a strong catalytic effect of plasma on methane decomposition. The degree of conversion after discharge increased drastically, despite gas cooling, because of heat absorption in the methane decomposition reaction. Theoretical analysis of process kinetics and energy balance gave clear evidence of the catalytic effect of plasma under experimental conditions. The estimated chain length was about 300. The possible mechanism of plasma catalysis, the ion-molecular chain Winchester mechanism, is proposed and described.

Potapkin, B.; Rusanov, V.; Jivotov, V.; Babaritski, A.; Potechin, S.; Etievant, C.

1997-10-01

328

Thermal Decomposition of Radiation-Damaged Polystyrene  

SciTech Connect

The radiation-damaged polystyrene material (''polycube'') used in this study was synthesized by mixing a high-density polystyrene (''Dylene Fines No. 100'') with plutonium and uranium oxides. The polycubes were used on the Hanford Site in the 1960s for criticality studies to determine the hydrogen-to-fissile atom ratios for neutron moderation during processing of spent nuclear fuel. Upon completion of the studies, two methods were developed to reclaim the transuranic (TRU) oxides from the polymer matrix: (1) burning the polycubes in air at 873 K; and (2) heating the polycubes in the absence of oxygen and scrubbing the released monomer and other volatile organics using carbon tetrachloride. Neither of these methods was satisfactory in separating the TRU oxides from the polystyrene. Consequently, the remaining polycubes were sent to the Hanford Plutonium Finishing Plant (PFP) for storage. Over time, the high dose of alpha and gamma radiation has resulted in a polystyrene matrix that is highly cross-linked and hydrogen deficient and a stabilization process is being developed in support of Defense Nuclear Facility Safety Board Recommendation 94-1. Baseline processes involve thermal treatment to pyrolyze the polycubes in a furnace to decompose the polystyrene and separate out the TRU oxides. Thermal decomposition products from this degraded polystyrene matrix were characterized by Pacific Northwest National Laboratory to provide information for determining the environmental impact of the process and for optimizing the process parameters. A gas chromatography/mass spectrometry (GC/MS) system coupled to a horizontal tube furnace was used for the characterization studies. The decomposition studies were performed both in air and helium atmospheres at 773 K, the planned processing temperature. The volatile and semi-volatile organic products identified for the radiation-damaged polystyrene were different from those observed for virgin polystyrene. The differences were in the n umber of organic species generated and their concentrations.

J Abrefah GS Klinger

2000-09-26

329

Thermal decomposition of synthesised carbonate hydroxyapatite.  

PubMed

Heat treatments are used when sintering hydroxyapatite to make porous blocks and granules and during plasma spraying of coatings. Calcium : phosphorus ratio is known to affect the thermal decomposition behavior of hydroxyapatite. Hydroxyapatite with carbonate ions substituted for phosphate ions is more similar in composition to bone mineral. While it has been shown that carbonate apatite may be sintered, relatively little is known about its high temperature stability. Various atmospheres have been used in investigations into the thermal stability of hydroxyapatites and carbonate hydroxyapatites, including nitrogen, wet carbon dioxide air, water vapor and wet oxygen, but few of these studies were directly comparable. Previous work has shown that loss of carbonate from CHA at high temperature is time dependent, which suggests that rapid high temperature treatment may prevent carbonate loss during processing. This study investigated the effect of dry carbon dioxide, carbon dioxide containing 3% water, nitrogen and nitrogen containing 3% water on the phase composition of hydroxyapatite containing between 1.0 and 11.5 wt % carbonate rapidly heated to temperatures of between 700 and 1400 degrees C. Carbonate ion substitution was observed to decrease the temperature at which crystallisation occurred to a minimum of 700 degrees C for 11.8 wt % carbonate apatite heated in wet atmospheres. Atmosphere was found to appreciably affect the crystallization temperature and phase transformations of carbonate apatite containing 7.8 wt % carbonate. In wet and dry carbon dioxide atmospheres, crystallisation began in this material at 1100 and 900 degrees C, betaTCP was formed at 1500 and 1300 degrees C respectively. The high temperature decomposition of carbonate hydroxyapatite would appear to depend on the composition of the apatite and the atmosphere in which it is heated. PMID:15348582

Barralet, J; Knowles, J C; Best, S; Bonfield, W

2002-06-01

330

Litter decomposition on reclaimed coal mine spoils and soils in the arid southwest  

Microsoft Academic Search

Fiberglass litter bags containing stripped alfalfa stem litter and cellulose filter paper were deposited on and buried in an undisturbed soil, and on eight reclaimed topsoiled and nontopsoiled areas. Changes in decomposition potential, especially in the older nontopsoiled areas, at the 6 cm depth adversely influenced the early stages of litter decay. The older 4- and 5-year-old topsoiled areas had

P. R. Fresquez; E. F. Aldon; W. C. Lindemann

1985-01-01

331

FUEL DECOMPOSITION AND FLAME REACTIONS IN CONVERSION OF FUEL NITROGEN TO NOX  

EPA Science Inventory

The report describes an experimental and analytical research program conducted to provide information on the chemical phenomena involved in the conversion of air and fuel nitrogen to NOx. Under Task 1, Fuel Decomposition, early (preflame) reactions of fuel nitrogen species were i...

332

Kinetics of the Decomposition of Hydrogen Peroxide Catalyzed by Ferric Ethylenediaminetetraacetate Complex  

PubMed Central

Added substrates, acetone and t-butyl alcohol, strongly retard the decomposition of H2O2 brought about by ferric ethylenediaminetetraacetate (EDTA) at pH 8-9.5. Their relative effectiveness and the kinetic form of the retardation are consistent with their interruption of a hydroxyl radical chain that is propagated by HO· attack both upon H2O2 and on complexed and uncomplexed EDTA. Similar retardation is observed with decompositions catalyzed by ferric nitrilotriacetate and hemin, and it is proposed that such redox chains may be quite a general path for transition metal ion catalysis of H2O2 decomposition.

Walling, Cheves; Partch, Richard E.; Weil, Tomas

1975-01-01

333

Layout decomposition for triple patterning lithography  

Microsoft Academic Search

As minimum feature size and pitch spacing further decrease, triple patterning lithography (TPL) is a possible 193nm extension along the paradigm of double patterning lithography (DPL). However, there is very little study on TPL layout decomposition. In this paper, we show that TPL layout decomposition is a more difficult problem than that for DPL. We then propose a general integer

Bei Yu; Kun Yuan; Boyang Zhang; Duo Ding; David Z. Pan

2011-01-01

334

Symbolic Functional Decomposition Algorithm for FSM Implementation  

Microsoft Academic Search

This paper presents an algorithm of symbolic functional decomposition for the implementation of finite state machines in field programmable gate array (FPGA) circuits. Unlike previous approaches to this problem, which consist of separate encoding and mapping steps, this algorithm does not pre-encode the machine's states; instead, the states are encoded gradually during every step of the functional decomposition process (used

Piotr Szotkowski; Mariusz Rawski

2007-01-01

335

Fast Polar Decomposition of an Arbitrary Matrix  

Microsoft Academic Search

The polar decomposition of an m x n matrix A of full rank, where rn n, can be computed using a quadratically convergent algorithm ofHigham SIAMJ. Sci. Statist. Comput., 7 (1986), pp. 1160-1174). The algorithm is based on a Newton iteration involving a matrix inverse. It is shown how, with the use of a preliminary complete orthogonal decomposition, the algorithm

Nicholas J. Higham; Robert S. Schreiber

1990-01-01

336

Feature transform for ATR image decomposition  

Microsoft Academic Search

We have developed an approach to image decomposition for ATR applications called the `feature transform.' There are two aspects to the feature transform: (1) A collection of rich, sophisticated feature extraction routines, and (2) the orchestration of a hierarchical decomposition of the scene into an image description based on the features. We have expanded the approach into two directions, one

Davi Geiger; Robert Hummel; Barney Baldwin; Tyng-Luh Liu; Laxmi Parida

1995-01-01

337

Iris recognition using rapid Haar wavelet decomposition  

Microsoft Academic Search

In this paper, we propose an iris recognition system using a basic and fast Haar wavelet decomposition method to analyze the pattern of a human iris. This system has two main modules, which are the feature encoding and iris code matching modules. Among all feature extraction methods, Haar wavelet decomposition is chosen for its computational simplicity and speed in filtering

Tze Weng Ng; Thien Lang Tay; Siak Wang Khor

2010-01-01

338

Metallo-Organic Decomposition (MOD) film development  

NASA Technical Reports Server (NTRS)

The processing techniques and problems encountered in formulating metallo-organic decomposition (MOD) films used in contracting structures for thin solar cells are described. The use of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) techniques performed at Jet Propulsion Laboratory (JPL) in understanding the decomposition reactions lead to improvements in process procedures. The characteristics of the available MOD films were described in detail.

Parker, J.

1986-01-01

339

Decomposition of wavelet representations and Martin boundaries  

Microsoft Academic Search

We study a decomposition problem for a class of unitary representations associated with wavelet analysis, wavelet representations, but our framework is wider and has applications to multi-scale expansions arising in dynamical systems theory for non-invertible endomorphisms. Our main results offer a direct integral decomposition for the general wavelet representation, and we solve a question posed by Judith Packer. This entails

Dorin Ervin Dutkay; Palle E. T. Jorgensen; Sergei Silvestrov

2011-01-01

340

Network Decomposition and Locality in Distributed Computation  

Microsoft Academic Search

The authors introduce a concept of network decomposition, a partitioning of an arbitrary graph into small-diameter connected components, such that the graph created by contracting each component into a single node has low chromatic number. They present an efficient distributed algorithm for constructing such a decomposition and demonstrate its use for design of efficient distributed algorithms. The method yields new

Baruch Awerbuch; Andrew V. Goldbergt; Michael Luby; Serge A. Plotkin

1989-01-01

341

Post-Placement Functional Decomposition for FPGAs  

Microsoft Academic Search

This work explores the effect of adding a simple functional decomposition step to the traditional field programmable gate array (FPGA) CAD flow. Once placement has com- pleted, alternative decompositions of the logic on the critical path are examined for potential delay improvements. The placed circuit is then modified to use the best decomposi- tions found. Any placement illegalities introduced by

Valavan Manohararajah; Deshanand P. Singh; Stephen D. Brown; Zvonko G. Vranesic

342

Generalized Unified Decomposition of Ensemble Loss  

Microsoft Academic Search

Goebel et al. (4) presented a unied decomposition of en- semble loss for explaining ensemble performance. They considered demo- cratic voting schemes with uniform weights, where the various base clas- siers each can vote for a single class once only. In this article, we gener- alize their decomposition to cover weighted, probabilistic voting schemes and non-uniform (progressive) voting schemes. Empirical

Remco R. Bouckaert; Michael Goebel; Patricia J. Riddle

2006-01-01

343

Binary morphological subband decomposition for image coding  

Microsoft Academic Search

A binary waveform coding method based on morphological subband decomposition coupled with embedded zero-tree and entropy coding is described. This method can be utilized in text compression or bit-plane coding of images. Binary morphological subband decomposition operations are carried out in the Galois field(2), resulting in a computationally efficient structure. Simulation studies are presented

M. N. Gurcan; O. N. Gerek; A. E. Cetin

1996-01-01

344

Asbestos-induced decomposition of hydrogen peroxide  

Microsoft Academic Search

Decomposition of HâOâ by chrysotile asbestos was demonstrated employing titration with KMnOâ. The participation of OH radicals in this process was delineated employing the OH radical scavenger dimethyl sulfoxide (DMSO). A mechanism involving the Fenton and Haber-Weiss reactions as the pathway for the HâOâ decomposition and OH radical production is postulated.

M. K. Eberhardt; A. A. Roman-Franco; M. R. Quiles

1985-01-01

345

The Geography of Organic Decomposition Rates  

Microsoft Academic Search

Decomposition of organic matter is a critical link in the cycling of nutrients through vegetated ecosystems. The primary controls of decay rates are climatic energy and moisture and the chemical-physical nature of the organic matter. A model was developed which uses these controls to predict the geography of decomposition rates for Canada and the United States. Annual actual evapotranspiration (AE)

Vernon Meentemeyer

1984-01-01

346

STELLAR POPULATIONS OF LYMAN BREAK GALAXIES AT z {approx_equal} 1-3 IN THE HST/WFC3 EARLY RELEASE SCIENCE OBSERVATIONS  

SciTech Connect

We analyze the spectral energy distributions (SEDs) of Lyman break galaxies (LBGs) at z {approx_equal} 1-3 selected using the Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) UVIS channel filters. These HST/WFC3 observations cover about 50 arcmin{sup 2} in the GOODS-South field as a part of the WFC3 Early Release Science program. These LBGs at z {approx_equal} 1-3 are selected using dropout selection criteria similar to high-redshift LBGs. The deep multi-band photometry in this field is used to identify best-fit SED models, from which we infer the following results: (1) the photometric redshift estimate of these dropout-selected LBGs is accurate to within few percent; (2) the UV spectral slope {beta} is redder than at high redshift (z > 3), where LBGs are less dusty; (3) on average, LBGs at z {approx_equal} 1-3 are massive, dustier, and more highly star forming, compared to LBGs at higher redshifts with similar luminosities (0.1L* {approx}< L {approx}< 2.5L*), though their median values are similar within 1{sigma} uncertainties. This could imply that identical dropout selection technique, at all redshifts, finds physically similar galaxies; and (4) the stellar masses of these LBGs are directly proportional to their UV luminosities with a logarithmic slope of {approx}0.46, and star formation rates are proportional to their stellar masses with a logarithmic slope of {approx}0.90. These relations hold true-within luminosities probed in this study-for LBGs from z {approx_equal} 1.5 to 5. The star-forming galaxies selected using other color-based techniques show similar correlations at z {approx_equal} 2, but to avoid any selection biases, and for direct comparison with LBGs at z > 3, a true Lyman break selection at z {approx_equal} 2 is essential. The future HST UV surveys, both wider and deeper, covering a large luminosity range are important to better understand LBG properties and their evolution.

Hathi, N. P.; McCarthy, P. J. [Observatories of the Carnegie Institution for Science, Pasadena, CA 91101 (United States); Cohen, S. H.; Windhorst, R. A.; Rutkowski, M. J. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287-1404 (United States); Ryan, R. E. Jr.; Koekemoer, A. M.; Bond, H. E. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Finkelstein, S. L. [Department of Astronomy, University of Texas, Austin, TX 78712 (United States); Yan, H. [Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211 (United States); O'Connell, R. W. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904-4325 (United States); Straughn, A. N.; Kimble, R. A. [NASA-Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Balick, B. [Department of Astronomy, University of Washington, Seattle, WA 98195-1580 (United States); Calzetti, D. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Disney, M. J. [School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA (United Kingdom); Dopita, M. A. [Research School of Astronomy and Astrophysics, Australian National University, Weston Creek, ACT 2611 (Australia); Frogel, Jay A. [Astronomy Department, King Abdulaziz University, P.O. Box 80203, Jeddah (Saudi Arabia); Hall, D. N. B. [Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States); Holtzman, J. A., E-mail: nhathi@obs.carnegiescience.edu [Department of Astronomy, New Mexico State University, Las Cruces, NM 88003 (United States); and others

2013-03-10

347

How spinodal decomposition influences observables at FAIR energies  

NASA Astrophysics Data System (ADS)

The FAIR facility will make the region of high net-baryon densities experimentally accessible, where a first-order phase transition is conjectured. We investigate the dynamics of chiral symmetry breaking and the onset of confinement during a heavy-ion collision at large baryochemical potentials within a nonequilibrium chiral fluid dynamics model including effects of dissipation and noise. The order parameters are explicitly propagated and coupled to a fluid dynamically expanding medium of quarks. We demonstrate that the coupled system is strongly influenced by the nonequilibrium dynamics, leading only to a weak growth of the correlation length near the critical point. At the first-order phase transition, spinodal instabilities create domains in the order parameters and large spatial fluctuations in the baryon density within single events. As a consequence we find a clear enhancement of higher flow harmonics in coordinate space at the first-order phase transition in comparison with transitions through the crossover or critical point.

Herold, Christoph; Nahrgang, Marlene; Mishustin, Igor; Bleicher, Marcus

2014-04-01

348

Effects of low-level SO 2 fumigation on decomposition of western wheatgrass litter in a mixed-grass prairie  

Microsoft Academic Search

Litter bags were used to determine the effects of SO2 and substrate-S content on decomposition rates of western wheatgrass tillers in the field. Atmospheric SO2 decreased monthly decomposition rates 32 to 44% in spring and early summer and 12% in dry late summer. Increased S content of the substrate (980 ?g g?1 vs 590 ?g g?1 in control) had no

J. L. Dodd; W. K. Lauenroth

1981-01-01

349

Metallo-organic decomposition films  

NASA Technical Reports Server (NTRS)

A summary of metallo-organic deposition (MOD) films for solar cells was presented. The MOD materials are metal ions compounded with organic radicals. The technology is evolving quickly for solar cell metallization. Silver compounds, especially silver neodecanoate, were developed which can be applied by thick-film screening, ink-jet printing, spin-on, spray, or dip methods. Some of the advantages of MOD are: high uniform metal content, lower firing temperatures, decomposition without leaving a carbon deposit or toxic materials, and a film that is stable under ambient conditions. Molecular design criteria were explained along with compounds formulated to date, and the accompanying reactions for these compounds. Phase stability and the other experimental and analytic results of MOD films were presented.

Gallagher, B. D.

1985-01-01

350

Amino Acid Free Energy Decomposition  

NASA Astrophysics Data System (ADS)

The Distance Constraint Model (DCM) describes protein thermodynamics at a coarse-grained level based on a Free Energy Decomposition (FED) that assigns energy and entropy contributions to specific molecular interactions. Application of constraint theory accounts for non-additivity in conformational entropy so that the total free energy of a system can be reconstituted from all its molecular parts. In prior work, a minimal DCM utilized a simple FED involving temperature-independent parameters indiscriminately applied to all residues. Here, we describe a residue-specific FED that depends on local conformational states. The FED of an amino acid is constructed by weighting the energy spectrums associated with local energy minimums in configuration space by absolute entropies estimated using a quasi-harmonic approximation. Interesting temperature-dependent behavior is found. Support is from NIH R01 GM073082 and a CRI postdoctoral Duke research fellowship for H. Wang.

Wang, Hui; Fairchild, Michael; Livesay, Dennis; Jacobs, Donald

2009-03-01

351

Thermal decomposition of magnesium and calcium sulfates  

SciTech Connect

The effect of catalyst on the thermal decomposition of MgSO/sub 4/ and CaSO/sub 4/ in vacuum was studied as a function of time in Knudsen cells and for MgSO/sub 4/, in open crucibles in vacuum in a Thermal Gravimetric Apparatus. Platinum and Fe/sub 2/O/sub 3/ were used as catalysts. The CaSO/sub 4/ decomposition rate was approximately doubled when Fe/sub 2/O/sub 3/ was present in a Knudsen cell. Platinum did not catalyze the CaSO/sub 4/ decomposition reaction. The initial decomposition rate for MgSO/sub 4/ was approximately 5 times greater than when additives were present in Knudsen cells but only about 1.5 times greater when decomposition was done in an open crucible.

Roche, S L

1982-04-01

352

Multilinear operators for higher-order decompositions.  

SciTech Connect

We propose two new multilinear operators for expressing the matrix compositions that are needed in the Tucker and PARAFAC (CANDECOMP) decompositions. The first operator, which we call the Tucker operator, is shorthand for performing an n-mode matrix multiplication for every mode of a given tensor and can be employed to concisely express the Tucker decomposition. The second operator, which we call the Kruskal operator, is shorthand for the sum of the outer-products of the columns of N matrices and allows a divorce from a matricized representation and a very concise expression of the PARAFAC decomposition. We explore the properties of the Tucker and Kruskal operators independently of the related decompositions. Additionally, we provide a review of the matrix and tensor operations that are frequently used in the context of tensor decompositions.

Kolda, Tamara Gibson

2006-04-01

353

TE/TM decomposition of electromagnetic sources  

NASA Technical Reports Server (NTRS)

Three methods are given by which bounded EM sources can be decomposed into two parts radiating transverse electric (TE) and transverse magnetic (TM) fields with respect to a given constant direction in space. The theory applies source equivalence and nonradiating source concepts, which lead to decomposition methods based on a recursive formula or two differential equations for the determination of the TE and TM components of the original source. Decompositions for a dipole in terms of point, line, and plane sources are studied in detail. The planar decomposition is seen to match to an earlier result given by Clemmow (1963). As an application of the point decomposition method, it is demonstrated that the general exact image expression for the Sommerfeld half-space problem, previously derived through heuristic reasoning, can be more straightforwardly obtained through the present decomposition method.

Lindell, Ismo V.

1988-01-01

354

Decomposition of the sulfates of copper, iron (II), iron (III), nickel, and zinc: XPS, SEM, DRIFTS, XRD, and TGA study  

Microsoft Academic Search

The bulk and surface characteristics during decomposition of the transition metal sulfates of copper, iron (II), iron (III), nickel, and zinc are investigated utilizing various spectroscopic techniques. An oxidized form of sulfur was detected on the surface during decomposition of all metal sulfate samples, except zinc sulfate. Surface characteristics were not necessarily representative of the bulk characteristics. Oxy-sulfate was observed

Ranjani V Siriwardane; James A Poston Jr; Edward P Fisher; Ming-Shing Shen; Angela L Miltz

1999-01-01

355

Carbon isotope discrimination during litter decomposition can be explained by selective use of substrate with differing delta13C  

Microsoft Academic Search

Temporal dynamics of C isotopic composition (delta13C) of CO2 and leaf litter was monitored during a litter decomposition experiment using Arbutus unedo L., as a slow decomposing model substrate. This allowed us (1) to quantify isotopic discrimination variation during litter decomposition, and (2) to test whether selective substrate use or kinetic fractionation could explain the observed isotopic discrimination. Total cumulative

J. Ngao; M. F. Cotrufo

2011-01-01

356

DEVELOPMENT OF A NOVEL CATALYST FOR NO DECOMPOSITION  

SciTech Connect

Air pollution arising from the emission of nitrogen oxides as a result of combustion taking place in boilers, furnaces and engines, has increasingly been recognized as a problem. New methods to remove NOx emissions significantly and economically must be developed. The current technology for post-combustion removal of NO is the selective catalytic reduction (SCR) of NO by ammonia or possibly by a hydrocarbon such as methane. The catalytic decomposition of NO to give N{sub 2} will be preferable to the SCR process because it will eliminate the costs and operating problems associated with the use of an external reducing species. The most promising decomposition catalysts are transition metal (especially copper)-exchanged zeolites, perovskites, and noble metals supported on metal oxides such as alumina, silica, and ceria. The main shortcoming of the noble metal reducible oxide (NMRO) catalysts is that they are prone to deactivation by oxygen. It has been reported that catalysts containing tin oxide show oxygen adsorption behavior that may involve hydroxyl groups attached to the tin oxide. This is different than that observed with other noble metal-metal oxide combinations, which have the oxygen adsorbing on the noble metal and subsequently spilling over to the metal oxide. This observation leads one to believe that the Pt/SnO{sub 2} catalysts may have a potential as NO decomposition catalysts in the presence of oxygen. This prediction is also supported by some preliminary data obtained for NO decomposition on a Pt/SnO{sub 2} catalyst in the PI's laboratory. The main objective of the proposed research is the evaluation of the Pt/SnO{sub 2} catalysts for the decomposition of NO in simulated power plant stack gases with particular attention to the resistance to deactivation by O{sub 2}, CO{sub 2}, and elevated temperatures. Therefore, it is proposed to perform temperature programmed desorption (TPD) and temperature programmed reaction (TPRx) studies on Pt/SnO{sub 2} catalysts having different noble metal concentrations and pretreated under different conditions. It is also proposed to perform NO decomposition tests in a laboratory-size packed-bed reactor to obtain long-term deactivation data. In the previous reporting period some TPRx runs with the catalysts containing 15% and 10% Pt were repeated due to the uncertainty of the oxygen content of the feed. In this reporting period runs were made with feed gas mixtures containing water vapor. Two reaction regimes, one below and the other above 750 K were observed. Presence of water vapor slightly enhanced the catalyst activity, but decreased the selectivity towards N{sub 2} at low temperatures.

Ates Akyurtlu; Jale F. Akyurtlu

2005-09-29

357

Climatic influence on residue decomposition prediction in the Wind Erosion Prediction System  

NASA Astrophysics Data System (ADS)

The effectiveness of crop residues to protect the soil surface and reduce soil erosion decreases as residues decompose. The rate of residue decomposition is directly related to the temperature and moisture regimes of the residues. Predicting changes in residue mass, orientation, and soil cover requires the use of functions that relate changes in decomposition rates to changes in the temperature and water regimes. Temperature and water functions used in the residue decomposition submodel of the Wind Erosion Prediction System (WEPS) were evaluated for their effects on predictions of residue decomposition. A precipitation function (PC) was found to produce relatively more accurate estimates of decomposition than a near surface soil water content function (SWC) for describing water regime effects. The estimated accuracies of the two functions were similar when bias in the estimation was considered. Predictions made with PC had estimated accuracies of ± 11.4, 14.5, 13.5% for alfalfa, sorghum and wheat, respectively, while those made with SWC had estimated accuracies of ± 13.8, 16.2, and 16.9%, respectively. Three temperature functions were compared for use in predicting residue decomposition over a range of locations and crops. There was little difference between the temperature functions over all the locations but, for several locations, one function overpredicted decomposition more often than the other two functions. Accuracies ranged from ±4 to ±51% of the observed values. The highest values were obtained at one location, and all three temperature functions produced similar high values. Over most of the data, estimated accuracies were generally between ± 15 and ± 25%. The prediction intervals were similar to those observed for decomposition of surface-placed residues. This evaluation indicates that the temperature and water functions used in the WEPS decomposition submodel will give reasonable estimates of mass loss from surface residues using easy-to-obtain weather data.

Schomberg, H. H.; Steiner, J. L.; Evett, S. R.; Moulin, A. P.

1996-03-01

358

Concentration and Pressure Effects on the Decomposition Rate of Aqueous Hydroxylammonium Nitrate Solutionsa  

Microsoft Academic Search

Abstract— Decomposition experiments have been performed on liquid propellants consisting of mixtures of hydroxylammonium nitrate (HAN) and water. Electric discharge initiation was used to produce a propagating, exothermic decomposition wave front, which was then observed by cineshadowgraphy. Experiments were conducted on quiescent HAN-water mixtures of 3.12 to 13.00M HAN in a 1.8 x 1.0mm rectangular strand burner over pressures of

Steven R. Vosen

1989-01-01

359

Repair of early cholesterol-induced aortic lesions in rabbits after withdrawal from short-term atherogenic diet. Scanning electron-microscopical (SEM) and transmission electron-microscopical (TEM) observations.  

PubMed

Signs of repair of early atherosclerotic lesions after withdrawal of rabbits from a short-term atherogenic diet have been observed by means of scanning and transmission electron microscopy. The endothelial lining was lacking over large portions of the plaques during early atherogenesis. During the regression phase, hematic cholesterol values returned to normal, the smooth muscle cells of the plaques lost a large part of the lipids they had accumulated, while the surface of the plaques was covered by a continuous layer of endothelial cells. PMID:812509

Weber, G; Fabbrini, P; Capaccioli, E; Resi, L

1975-01-01

360

Emergence of electronic home monitoring in chronic heart failure: rationale, feasibility, and early results with the HomMed Sentry-Observer system.  

PubMed

Electronic home monitoring for chronic heart failure is emerging as an available option to add to our armamentarium as a vital part of the multidisciplinary care process. This investigation describes the early clinical results of a multicenter study that suggests that important trends in medical resource utilization may be attained by the use of this modality. (c)2000 by CHF, Inc. PMID:12029180

Mehra, M R; Uber, P A; Chomsky, D B; Oren, R

2000-01-01

361

Engaging Practitioners in Program Evaluation: A Preliminary Report of Perceptions and Observations of Practitioner-Caregiver Partnerships in Early Intervention. A Program Evaluation Report  

ERIC Educational Resources Information Center

Background: Many early intervention teams are shifting their service delivery for children with disabilities from a child-focused model to one that focuses on strengthening the competence and confidence of the child's caregivers (parents, childcare providers, preschool teachers). The use of coaching strategies in a primary coach model of service…

Bainter, Sue; Marvin, Chris

2006-01-01

362

Endoscopic decomposition of characters of certain cuspidal representations  

Microsoft Academic Search

We construct an endoscopic decomposition for local L-packets associated to irreducible cuspidal Deligne-Lusztig representations. Moreover, the obtained decomposition is compatible with inner twistings.

David Kazhdan; Yakov Varshavsky

2003-01-01

363

Ocean Models and Proper Orthogonal Decomposition  

NASA Astrophysics Data System (ADS)

The increasing computational developments and the better understanding of mathematical and physical systems resulted in an increasing number of ocean models. Long time ago, modelers were like a secret organization and recognize each other by using secret codes and languages that only a select group of people was able to recognize and understand. The access to computational systems was reduced, on one hand equipment and the using time of computers were expensive and restricted, and on the other hand, they required an advance computational languages that not everybody wanted to learn. Now a days most college freshman own a personal computer (PC or laptop), and/or have access to more sophisticated computational systems than those available for research in the early 80's. The resource availability resulted in a mayor access to all kind models. Today computer speed and time and the algorithms does not seem to be a problem, even though some models take days to run in small computational systems. Almost every oceanographic institution has their own model, what is more, in the same institution from one office to the next there are different models for the same phenomena, developed by different research member, the results does not differ substantially since the equations are the same, and the solving algorithms are similar. The algorithms and the grids, constructed with algorithms, can be found in text books and/or over the internet. Every year more sophisticated models are constructed. The Proper Orthogonal Decomposition is a technique that allows the reduction of the number of variables to solve keeping the model properties, for which it can be a very useful tool in diminishing the processes that have to be solved using "small" computational systems, making sophisticated models available for a greater community.

Salas-de-Leon, D. A.

2007-05-01

364

Metal-dielectric interface toughening by molecular nanolayer decomposition  

NASA Astrophysics Data System (ADS)

Recent work has shown that copper-silica interfaces can be toughened several fold by combining interface functionalization with an organosilane molecular nanolayer (MNL) and thermal annealing. In order to understand the role of annealing-induced MNL instabilities on interface toughness, we studied the effects of interface chemical changes on the fracture toughness of copper-silica interfaces tailored with organosilane or organogermane MNLs. Our results indicate that MNL decomposition into its inorganic constituents and consequent intermixing can provide an interface toughening mechanism. Organogermane-tailored interfaces exhibit higher toughness values due to Ge-diffusion induced copper silicate formation, not observed at organosilane tailored interfaces. These findings show that organic nanolayer decomposition at a buried interface could be exploited to tailor interfacial properties through appropriate choice of MNL chemistry and processing treatments.

Garg, Saurabh; Jain, Ashutosh; Karthik, C.; Singh, Binay; Teki, Ranganath; Smentkowski, V. S.; Lane, Michael W.; Ramanath, Ganpati

2010-08-01

365

On a Decomposition Model for Optical Flow  

NASA Astrophysics Data System (ADS)

In this paper we present a variational method for determining cartoon and texture components of the optical flow of a noisy image sequence. The method is realized by reformulating the optical flow problem first as a variational denoising problem for multi-channel data and then by applying decomposition methods. Thanks to the general formulation, several norms can be used for the decomposition. We study a decomposition for the optical flow into bounded variation and oscillating component in greater detail. Numerical examples demonstrate the capabilities of the proposed approach.

Abhau, Jochen; Belhachmi, Zakaria; Scherzer, Otmar

366

Accuracy of radial-velocity measurements for early-type stars. II. Investigations of spectrum mismatch from high-resolution observations  

Microsoft Academic Search

The accuracy with which radial velocities of early-type stars can be measured is limited in practice by the existence of asymmetrical differences between object and template spectrum, constituting ``spectrum mismatch''. Our studies of the magnitude of spectrum-mismatch errors, commenced in Paper I (Verschueren et al. \\\\cite{VDG99}) on the basis of synthetic spectra having different attributes of effective temperature (Teff and

R. E. M. Griffin; M. David; W. Verschueren

2000-01-01

367

Unimolecular thermal decomposition of dimethoxybenzenes.  

PubMed

The unimolecular thermal decomposition mechanisms of o-, m-, and p-dimethoxybenzene (CH3O-C6H4-OCH3) have been studied using a high temperature, microtubular (?tubular) SiC reactor with a residence time of 100 ?s. Product detection was carried out using single photon ionization (SPI, 10.487 eV) and resonance enhanced multiphoton ionization (REMPI) time-of-flight mass spectrometry and matrix infrared absorption spectroscopy from 400 K to 1600 K. The initial pyrolytic step for each isomer is methoxy bond homolysis to eliminate methyl radical. Subsequent thermolysis is unique for each isomer. In the case of o-CH3O-C6H4-OCH3, intramolecular H-transfer dominates leading to the formation of o-hydroxybenzaldehyde (o-HO-C6H4-CHO) and phenol (C6H5OH). Para-CH3O-C6H4-OCH3 immediately breaks the second methoxy bond to form p-benzoquinone, which decomposes further to cyclopentadienone (C5H4=O). Finally, the m-CH3O-C6H4-OCH3 isomer will predominantly follow a ring-reduction/CO-elimination mechanism to form C5H4=O. Electronic structure calculations and transition state theory are used to confirm mechanisms and comment on kinetics. Implications for lignin pyrolysis are discussed. PMID:24952536

Robichaud, David J; Scheer, Adam M; Mukarakate, Calvin; Ormond, Thomas K; Buckingham, Grant T; Ellison, G Barney; Nimlos, Mark R

2014-06-21

368

Unimolecular thermal decomposition of dimethoxybenzenes  

NASA Astrophysics Data System (ADS)

The unimolecular thermal decomposition mechanisms of o-, m-, and p-dimethoxybenzene (CH3O-C6H4-OCH3) have been studied using a high temperature, microtubular (?tubular) SiC reactor with a residence time of 100 ?s. Product detection was carried out using single photon ionization (SPI, 10.487 eV) and resonance enhanced multiphoton ionization (REMPI) time-of-flight mass spectrometry and matrix infrared absorption spectroscopy from 400 K to 1600 K. The initial pyrolytic step for each isomer is methoxy bond homolysis to eliminate methyl radical. Subsequent thermolysis is unique for each isomer. In the case of o-CH3O-C6H4-OCH3, intramolecular H-transfer dominates leading to the formation of o-hydroxybenzaldehyde (o-HO-C6H4-CHO) and phenol (C6H5OH). Para-CH3O-C6H4-OCH3 immediately breaks the second methoxy bond to form p-benzoquinone, which decomposes further to cyclopentadienone (C5H4=O). Finally, the m-CH3O-C6H4-OCH3 isomer will predominantly follow a ring-reduction/CO-elimination mechanism to form C5H4=O. Electronic structure calculations and transition state theory are used to confirm mechanisms and comment on kinetics. Implications for lignin pyrolysis are discussed.

Robichaud, David J.; Scheer, Adam M.; Mukarakate, Calvin; Ormond, Thomas K.; Buckingham, Grant T.; Ellison, G. Barney; Nimlos, Mark R.

2014-06-01

369

Thermal decomposition of energetic materials  

NASA Astrophysics Data System (ADS)

The studies of thermal decomposition to identify mechanisms and quantify kinetic parameters are complex and its extrapolation to real scale could be not acceptable. Using an intermediate scale setup, three typical explosives, AN, PETN and RDX, with an inert material (silica sand) are submitted to fast heating rate. The experimental apparatus is based in a propane/air burner, a combustion chamber and a glass tube. Through the fuel/air ratio and the distance between the combustion chamber and the sample container is set different temperatures of the combustion gases. Mass loss and the temperatures evolution are measured simultaneously. The experimental results, obtained for samples with 500 mg weight, are compared with its obtained using DSC. The theoretical approach is based in the model of Zinn & Mader. The kinetic parameters, the ignition temperature and time are determined as a function of heating rate (HR) and particle size of inert and energetic materials. Except for AN, the theoretical results are generally in good agreement with those obtained by the experimental setup, for range between 132 and 576 °C/min, and by DSC for HR of 10 and 20 °C/min. The ignition time decreases exponentially with increasing temperature of combustion gases. .

Carda~O, Pedro A.; Gois, José C.; Campos, José A.

2000-04-01

370

Thermal Decomposition of Energetic Materials  

NASA Astrophysics Data System (ADS)

The studies of thermal decomposition to identify mechanisms and quantify kinetic parameters are complex and extrapolation to real scale could not be acceptable. Using an intermediate scale setup, three typical explosives, AN, PETN and RDX, with an inert material (silica sand) were submitted to fast heating rate. The experimental apparatus is based in a propane/air burner, a combustion chamber and a glass tube. Through the fuel/air ratio and the distance between the combustion chamber and the sample container was set different temperatures of the combustion gases. Mass loss and the temperature evolution were measured simultaneously. The experimental results, obtained for samples with 500 mg weight, are compared with its obtained using DSC. The theoretical approach was based in the model of Zinn & Mader. The kinetic parameters, the ignition temperature and time were determined as a function of heating rate (HR) and particle size of inert and energetic materials. Out of AN, which gives low values, the theoretical results are in good agreement with its obtained by the experimental setup, for range between 100 and 600 ^oC/min, and by DSC for HR of 10 and 20 ^oC/min. The ignition time decreases exponentially with the increase of the temperature of combustion gases.

Cardão, P.; Gois, J. C.; Campos, J.

1999-06-01

371

Thermal Decomposition Kinetics of HMX  

SciTech Connect

Nucleation-growth kinetic expressions are derived for thermal decomposition of HMX from a variety of types of data, including mass loss for isothermal and constant rate heating in an open pan, and heat flow for isothermal and constant rate heating in open and closed pans. Conditions are identified in which thermal runaway is small to nonexistent, which typically means temperatures less than 255 C and heating rates less than 1 C/min. Activation energies are typically in the 140 to 165 kJ/mol regime for open pan experiments and about 150-165 kJ/mol for sealed-pan experiments. The reaction clearly displays more than one process, and most likely three processes, which are most clearly evident in open pan experiments. The reaction is accelerated for closed pan experiments, and one global reaction fits the data fairly well. Our A-E values lie in the middle of the values given in a compensation-law plot by Brill et al. (1994). Comparison with additional open and closed low temperature pyrolysis experiments support an activation energy of 165 kJ/mol at 10% conversion.

Burnham, A K; Weese, R K

2005-03-17

372

Architecture-driven Problem Decomposition  

Microsoft Academic Search

Jackson's Problem Frames provide a means of analysing and decomposing problems. They emphasise the world out- side the computer helping the developer to focus on the problem domain instead of drifting into inventing solutions. The intention is to delay consideration of the solution space until a good understanding of the problem is gained. In contrast, early consideration of a solution

Lucia Rapanotti; Jon G. Hall; Michael Jackson; Bashar Nuseibeh

2004-01-01

373

Strain localization driven by thermal decomposition during seismic shear  

NASA Astrophysics Data System (ADS)

De Paola et al. [2008] analyzed a series of faults in the Northern Apennines, Italy, hosted in anhydrite and dolomite rocks. They found a highly localized band of less than 100 microns, contained within a broader damage zone. Recent High-Velocity Friction (HVF) experiments on kaolinite-bearing gouge samples (Brantut et al. [2008]) have also shown extreme localization in samples undergoing thermal decomposition. They performed microstructural analysis on HVF samples and found an "ultralocalized deformation zone", less than ten microns wide, interpreted to be the main slipping zone in the experiment. By measuring relative humidity in the sample chamber they were also able to observe the thermal dehydration of kaolinite. These laboratory and field observations indicate that straining is extremely localized in fault materials where thermal decomposition reactions may occur. During thermal decomposition reactions pore fluid is released, leading to increases in pore pressure, and a corresponding drop in frictional heating. The reactions are endothermic, so heat is also absorbed as the reactions progress. Previous work by Sulem and Famin [2009] has investigated how these effects influence the evolution of pore pressure and temperature in a uniformly sheared gouge layer. They found that accounting for thermal decomposition reactions leads to significant pore pressure increases, and that the endothermic nature of the reaction acts to cap the maximum temperature achieved. In previous work (Platt, Rudnicki and Rice [2010]) we investigated strain localization using a model for shearing of a fluid-saturated gouge material, finding a formula for the localized zone width as a function of physical properties of the gouge. We now extend this model to include thermal decomposition. Using linear stability methods and an idealized reaction kinetic we infer a new localized zone width when decomposition is accounted for. Numerical simulations then allow us to compare this prediction to results obtained using a realistic Arrhenius kinetic relation for the reaction. We find qualitative agreement between our two methods and find that thermal decomposition is very important when attempting to predict the severity of strain localization. The presence of the reaction localizes the deformation to zones as narrow as a few microns. Reaction-driven, strain localization leads to dramatic dynamic weakening when the fault material reaches a critical reaction temperature, suggesting that thermal decomposition plays an important role in large-scale earthquake mechanics. Furthermore, as reactive material is depleted during the rupture, the localized zone migrates across the fault, towards unreacted material. Finally we use our model to investigate earthquakes occurring at different depths. We know that ambient temperature and compressive stresses increase with depth. Thus, deeper earthquakes begin closer to the critical reaction temperature and experience more frictional heating. We systematically change the ambient temperature and compressive stress in our model, allowing us to compare events occurring at different depths, and make connections between observations in HVF experiments and seismic events.

Platt, J. D.; Brantut, N.; Rice, J. R.

2011-12-01

374

Radiation-induced decomposition of PETN and TATB under extreme conditions.  

PubMed

We conducted a series of experiments investigating decomposition of secondary explosives PETN and TATB at varying static pressures and temperatures using synchrotron radiation. As seen in our earlier work, the decomposition rate of TATB at ambient temperature slows systematically with increasing pressure up to at least 26 GPa but varies little with pressure in PETN at ambient temperature up to 15.7 GPa, yielding important information pertaining to the activation complex volume in both cases. We also investigated the radiation-induced decomposition rate as a function of temperature at ambient pressure and 26 GPa for TATB up to 403 K, observing that the decomposition rate increases with increasing temperature as expected. The activation energy for the TATB reaction at ambient temperature was experimentally determined to be 16 +/- 3 kJ/mol. PMID:18335910

Giefers, Hubertus; Pravica, Michael

2008-04-17

375

Radiation-Induced Decomposition of PETN and TATB under Extreme Conditions  

SciTech Connect

We conducted a series of experiments investigating decomposition of secondary explosives PETN and TATB at varying static pressures and temperatures using synchrotron radiation. As seen in our earlier work, the decomposition rate of TATB at ambient temperature slows systematically with increasing pressure up to at least 26 GPa but varies little with pressure in PETN at ambient temperature up to 15.7 GPa, yielding important information pertaining to the activation complex volume in both cases. We also investigated the radiation-induced decomposition rate as a function of temperature at ambient pressure and 26 GPa for TATB up to 403 K, observing that the decomposition rate increases with increasing temperature as expected. The activation energy for the TATB reaction at ambient temperature was experimentally determined to be 16 {+-} 3 kJ/mol.

Giefers, Hubertus; Pravica, Michael (UNLV)

2008-11-03

376

NMR analysis of diacyl peroxide decomposition in methanol in response to temperature and microwave radiation  

NASA Astrophysics Data System (ADS)

We have studied the decomposition of benzoyl and acetyl benzoyl peroxides in methanol-d4 in response to temperature and microwave radiation. We have shown that chemically-induced dynamic nuclear polarization (CIDNP) can be observed even when the reactions are carried out in spectrometers with high magnetic fields. In this case, spin correlation persists in geminal radical pairs involving labile acyloxyl radicals. Regardless of the method used to initiate peroxide decomposition, the same amount of products are formed. Homolysis occurs according to a chain mechanism. The contribution of induced decomposition decreases over the course of the reaction. Dissolved oxygen molecules efficiently terminate the chain, decreasing the rate of peroxide decomposition. In the case of acetyl benzoyl peroxide, the product yield depends on the initiation mechanism: for microwave irradiation, the solvent molecules are more active while dissolved oxygen is less active than in thermolysis.

Haidukevich, O. A.; Skakovskii, E. D.; Tychinskaya, L. Yu.; Zvereva, T. D.; Dikusar, E. A.; Lamotkin, S. A.; Rykov, S. V.

2012-05-01

377

Ceramic decomposition under irradiation, 1987. Progress report  

SciTech Connect

Our quantitative determinations of the decomposition of thin film and bulk ceramic materials during electron microscopy has shown that the radiation damage effect is a complex one depending dielectric and thermochemical properties. In low melting temperature glasses, for example, much of the activity is due to field enhanced diffusion of low atomic weight species. This is particularly true of bulk specimens and for the case of binary soda-borosilicate glass the sodium depletion in the SEM can be quantitatively described in terms of this effect. Studies with thin specimens of refractory carbides show that in these materials the carbon depletion is due to direct displacement processes and that here the electric fields give rise to recombination effects. The studies of ceramic thin films suitable for reference standards is continuing as a joint effort with the Rockwell Science Center. Work is in progress to describe the in plane crystallization that is observed in terms of the latent heat involved and the configurational entropy of the propagating interface.

Howitt, D.G.

1987-12-31

378

Model uncertainty analysis by variance decomposition  

NASA Astrophysics Data System (ADS)

Errors and uncertainties in hydrological, hydraulic and environmental models are often substantial. In good modelling practice, they are quantified in order to supply decision-makers with important additional information on model limitations and sources of uncertainty. Several uncertainty analysis methods exist, often with various underlying assumptions. One of these methods is based on variance decomposition. The method allows splitting the variance of the total error in the model results (as estimated after comparing model results with observations) in its major contributing uncertainty sources. This paper discusses an advanced version of that method where error distributions for rainfall, other inputs and parameters are propagated in the model and the “rest” uncertainties considered as model structural errors for different parts of the model. By expert knowledge, the iid assumption that is often made in model error analysis is addressed upfront. The method also addresses the problems of heteroscedasticity and serial dependence of the errors involved. The method has been applied by the author to modelling applications of sewer water quantity and quality, river water quality and river flooding.

Willems, P.

379

Decomposition of Aquatic Plants in Lakes.  

National Technical Information Service (NTIS)

This study was carried out to systematically determine the effects of temperature and oxygen concentration, two environmental parameters crucial to lake metabolism in general, on decomposition of five species of aquatic vascular plants of three growth for...

G. L. Godshalk

1977-01-01

380

Unimolecular decomposition of methyltrichlorosilane: RRKM calculations  

SciTech Connect

Based on reaction thermochemistry and estimates of Arrhenius A-factors, it is expected that Si-C bond cleavage, C-H bond cleavage, and HCl elimination will be the primary channels for the unimolecular decomposition of methyltrichlorosilane. Using RRKM theory, we calculated rate constants for these three reactions. The calculations support the conclusion that these three reactions are the major decomposition pathways. Rate constants for each reaction were calculated in the high-pressure limit (800--1500 K) and in the falloff regime (1300--1500 K) for bath gases of both helium and hydrogen. These calculations thus provide branching fractions as well as decomposition rates. We also calculated bimolecular rate constants for the overall decomposition in the low-pressure limit. Interesting and surprising kinetic behavior of this system and the individual reactions is discussed. The reactivity of this chlorinated organosilane is compared to that of other organosilanes.

Osterheld, T.H.; Allendorf, M.D.; Melius, C.F.

1993-06-01

381

Ceramic Decomposition under Irradiation: Progress Report.  

National Technical Information Service (NTIS)

Our quantitative determinations of the decomposition of thin film and bulk ceramic materials during electron microscopy has shown that the radiation damage effect is a complex one depending upon the dielectric properties. In low-melting-temperature glasse...

D. G. Howitt

1987-01-01

382

Logic Decomposition of Asynchronous Circuits Using Unfoldings.  

National Technical Information Service (NTIS)

A technique for logic decomposition of asynchronous circuits which works on STG unfolding prefixes rather than state graphs is proposed. It retains all the advantages of the state space based approach, such as the possibility of multiway acknowledgement, ...

V. Khomenko

2010-01-01

383

Total sequence decomposition distinguishes functional modules, \\  

Microsoft Academic Search

Background: Total sequence decomposition, using the web-based MASIA tool, identifies areas of conservation in aligned protein sequences. By structurally annotating these motifs, the sequence can be parsed into individual building blocks, molecular legos (\\

Catherine H. Schein; Numan Özgün; Tadahide Izumi; Werner Braun

2002-01-01

384

Model for Thermal Decomposition of Hydrogen Peroxide.  

National Technical Information Service (NTIS)

A one-dimensional model has been developed to investigate the thermal decomposition of rocket grade hydrogen peroxide (HP) in a stream of previously decomposed HP products. The model developed assumes steady, one-dimensional adiabatic flow and includes ba...

S. D. Heister W. E. Anderson J. H. Corpening B. L. Austin

2004-01-01

385

Thermodynamics and kinetics of methyltrichlorosilane decomposition.  

National Technical Information Service (NTIS)

Silicon carbide (SiC) deposition for oxidation- and corrosion-resistant coatings typically uses methyltrichlorosilane (MTS) as a starting reactant. Little is known about the temperature and pressure dependence of the unimolecular decomposition of MTS. In ...

C. F. Melius M. D. Allendorf T. H. Osterheld

1993-01-01

386

Solar Furnace Study of Zinc Sulfate Decomposition.  

National Technical Information Service (NTIS)

The objectives of this study are: to establish the applicability of solar central receivers to thermochemical cycles that can utilize solid sulfate decomposition as the high temperature step; to demonstrate the use of a rotating kiln that has been designe...

O. H. Krikorian P. K. Shell

1981-01-01

387

Initiation and Decomposition of Green Energetic Materials.  

National Technical Information Service (NTIS)

Recently there has been increased interest in high nitrogen content 'green' energetic materials which are designed to produce relatively non-toxic decomposition products as part of a push to decrease the environmental impact of energetic materials through...

M. R. Zachariah N. W. Piekiel R. E. Cavicchi

2010-01-01

388

Unimolecular decomposition of methyltrichlorosilane. RRKM calculations  

SciTech Connect

On the basis of reaction thermochemistry and estimates of Arrhenius A factors, it is expected that Si-C bond cleavage, C-H bond cleavage, and HCl elimination will be the primary channels for the unimolecular decomposition of methyltrichlorosilane. Using RRKM theory, we calculated rate constants for these three reactions. The calculations support the conclusion that these three reactions are the major decomposition pathways. Rate constants for each reaction were calculated in the high-pressure limit (800-1500 K) and in the falloff regime (1300-1500 K) for bath gases of both helium and hydrogen. These calculations thus provide branching fractions as well as decomposition rates. We also calculated bimolecular rate constants for the overall decomposition in the low-pressure limit. Interesting and surprising kinetic behavior of this system and the individual reactions is discussed. The reactivity of this chlorinated organosilane is compared to that of other organosilanes. 74 refs., 6 figs., 6 tabs.

Osterheld, T.H.; Allendorf, M.D.; Melius, C.F. (Sandia National Lab., Livermore, CA (United States))

1994-07-14

389

A novel methodology for triple/multiple-patterning layout decomposition  

NASA Astrophysics Data System (ADS)

Double patterning (DP) in a litho-etch-litho-etch (LELE) process is an attractive technique to scale the K1 factor below 0.25. For dense bidirectional layers such as the first metal layer (M1), however, density scaling with LELE suffers from poor tip-to-tip (T2T) and tip-to-side (T2S) spacing. As a result, triple-patterning (TP) in a LELELE process has emerged as a strong alternative. Because of the use of a third exposure/etch, LELELE can achieve good T2T and T2S scaling as well as improved pitch scaling over LELE in case further scaling is needed. TP layout decomposition, a.k.a. TP coloring, is much more challenging than DP layout decomposition. One of the biggest complexities of TP decomposition is that a stitch can be between different two-mask combinations (i.e. first/second, first/third, second/third) and, consequently, stitches are color-dependent and candidate stitch locations can be determined only during/after coloring. In this paper, we offer a novel methodology for TP layout decomposition. Rather than simplifying the TP stitching problem by using DP candidate stitches only (as in previous works), the methodology leverages TP stitching capability by considering additional candidate stitch locations to give coloring higher flexibility to resolve decomposition conflicts. To deal with TP coloring complexity, the methodology employs multiple DP coloring steps, which leverages existing infrastructure developed for DP layout decomposition. The method was used to decompose bidirectional M1 and M2 layouts at 45nm, 32nm, 22nm, and 14nm nodes. For reasonably dense layouts, the method achieves coloring solutions with no conflicts (or a reasonable number of conflicts solvable with manual legalization). For very dense and irregular M1 layouts, however, the method was unable to reach a conflict-free solution and a large number of conflicts was observed. Hence, layout simplifications for the M1 layer may be unavoidable to enable TP for the M1 layer. Although we apply the method for TP, the method is more general and can be applied for multiple patterning with any number of masks.

Ghaida, Rani S.; Agarwal, Kanak B.; Liebmann, Lars W.; Nassif, Sani R.; Gupta, Puneet

2012-03-01

390

QRS complex detection using Empirical Mode Decomposition  

Microsoft Academic Search

In this paper, we present a new Empirical Mode Decomposition based algorithm for the purpose of QRS complex detection. This algorithm requires the following stages: a high-pass filter, signal Empirical Mode Decomposition, a nonlinear transform, an integration and finally, a low-pass filter is used. In order to evaluate the proposed technique, the well known ECG MIT–BIH database has been used.

Zine-Eddine Hadj Slimane; Amine Naït-Ali

2010-01-01

391

Spectral estimation methods avoiding eigenvector decomposition  

Microsoft Academic Search

The autoregressive principal component technique uses the singular value decomposition (SVD) of an augmented dimension estimated autocorrelation matrix R to provide an accurate identification of frequencies in white noise. To avoid the eigen-decomposition of the matrix R, S.M. Kay and A.K. Shaw (1988) have applied a transformation on the inverse of R that truncates the eigenvalues associated with the noise.

T. Pitarque; G. Alengrin; A. Ferrari

1990-01-01

392

Decomposition of water behind reflected shock waves  

Microsoft Academic Search

Water was introduced into a shock tube via two reactions: Dâ + Oâ and Dâ + COâ. The decomposition was measured in an Ar--Kr diluent by recording the infrared emission from DâO through an interference filter centered at 3.8 ..mu..m. The resulting intensity--time profiles were fit to a first-order decay equation. The apparent decomposition rate constants derived from both sets

J. M. Bopp; R. D. Kern; T. Niki

1978-01-01

393

Aida:. Astronomical Image Decomposition and Analysis  

NASA Astrophysics Data System (ADS)

We present a package (Astronomical Image Decomposition and Analysis, AIDA), developed in IDL, specifically designed to perform 2D model fitting of quasar images. The software provides simultaneous decomposition into nuclear and host components. AIDA is a "user-friendly" software, which can work both in "interactive" and "batch" mode and manage complex PSF models (including HST and AO psf), and allows one to characterize its spatial variability in the field.

Uslenghi, Michela; Falomo, Renato

2007-12-01

394

Management intensity alters decomposition via biological pathways  

Microsoft Academic Search

Current conceptual models predict that changes in plant litter chemistry during decomposition are primarily regulated by both\\u000a initial litter chemistry and the stage—or extent—of mass loss. Far less is known about how variations in decomposer community\\u000a structure (e.g., resulting from different ecosystem management types) could influence litter chemistry during decomposition.\\u000a Given the recent agricultural intensification occurring globally and the importance

Kyle WickingsA; A. Stuart Grandy; Sasha Reed; Cory Cleveland

2011-01-01

395

Asbestos-induced decomposition of hydrogen peroxide  

SciTech Connect

Decomposition of H/sub 2/O/sub 2/ by chrysotile asbestos was demonstrated employing titration with KMnO/sub 4/. The participation of OH radicals in this process was delineated employing the OH radical scavenger dimethyl sulfoxide (DMSO). A mechanism involving the Fenton and Haber-Weiss reactions as the pathway for the H/sub 2/O/sub 2/ decomposition and OH radical production is postulated.

Eberhardt, M.K.; Roman-Franco, A.A.; Quiles, M.R.

1985-08-01

396

Critical analysis of nitramine decomposition data: Activation energies and frequency factors for HMX and RDX decomposition  

NASA Technical Reports Server (NTRS)

A summary of a literature review on thermal decomposition of HMX and RDX is presented. The decomposition apparently fits first order kinetics. Recommended values for Arrhenius parameters for HMX and RDX decomposition in the gaseous and liquid phases and for decomposition of RDX in solution in TNT are given. The apparent importance of autocatalysis is pointed out, as are some possible complications that may be encountered in interpreting extending or extrapolating kinetic data for these compounds from measurements carried out below their melting points to the higher temperatures and pressure characteristic of combustion.

Schroeder, M. A.

1980-01-01

397

CUR matrix decompositions for improved data analysis  

PubMed Central

Principal components analysis and, more generally, the Singular Value Decomposition are fundamental data analysis tools that express a data matrix in terms of a sequence of orthogonal or uncorrelated vectors of decreasing importance. Unfortunately, being linear combinations of up to all the data points, these vectors are notoriously difficult to interpret in terms of the data and processes generating the data. In this article, we develop CUR matrix decompositions for improved data analysis. CUR decompositions are low-rank matrix decompositions that are explicitly expressed in terms of a small number of actual columns and/or actual rows of the data matrix. Because they are constructed from actual data elements, CUR decompositions are interpretable by practitioners of the field from which the data are drawn (to the extent that the original data are). We present an algorithm that preferentially chooses columns and rows that exhibit high “statistical leverage” and, thus, in a very precise statistical sense, exert a disproportionately large “influence” on the best low-rank fit of the data matrix. By selecting columns and rows in this manner, we obtain improved relative-error and constant-factor approximation guarantees in worst-case analysis, as opposed to the much coarser additive-error guarantees of prior work. In addition, since the construction involves computing quantities with a natural and widely studied statistical interpretation, we can leverage ideas from diagnostic regression analysis to employ these matrix decompositions for exploratory data analysis.

Mahoney, Michael W.; Drineas, Petros

2009-01-01

398

Hydrogen Sulfide Decomposition in Pulsed Corona Discharge Reactors  

NASA Astrophysics Data System (ADS)

Hydrogen sulfide (H2S) decomposition was carried out in each of four balance gases (Ar, He, N2 and H2) in a wire-in-tube pulsed corona discharge reactor. H2S conversion rates and H2S decomposition energy efficiencies depend on the balance gas and H2S concentrations. H2S conversion in monatomic balance gases, like Ar and He, is more efficient than in diatomic balance gases like N2 and H2. Low pulse forming capacitance, low charge voltage, and high pulse frequency operation produces the highest energy efficiency for H2S conversion at constant power. H2S conversion is more efficient in Ar-N2 gas mixture than in Ar or N2