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1

Decomposition of an Al-Li alloy - The early stages observed by HREM  

Microsoft Academic Search

Using HREM, the decomposition of an Al-7 at. pct Li alloy during isothermal aging at 463 K was studied. Ordered precipitates with radii down to 0.5 nm were resolved. The size distributions of the precipitates and the decomposition parameters such as the mean radius, particle density, and precipitated volume fraction were measured. The time dependence of these parameters is well

G. Schmitz; P. Haasen

1992-01-01

2

An “observer decomposition” for Everett's theory  

Microsoft Academic Search

Several authors have noted that Everett's theory needs a specification of a “special decomposition” in order to account for our perceived experience, including quantum measurement results. It is suggested here that a possible way to arrive at such a specification is to relate it to the internal structure of the observer himself.

Yoav Ben-Dov

1990-01-01

3

Density dependence of isospin observables in spinodal decomposition  

SciTech Connect

Isotopic fluctuations in fragment formation are investigated in a quasianalytical description of the spinodal decomposition scenario. By exploiting the fluctuation-dissipation relations the covariance matrix of density fluctuations is derived as a function of the wave vector k for nuclear matter at given values of density, charge asymmetry, temperature, and the time that the system spends in the instability region. Then density fluctuations in ordinary space are implemented with a Fourier transform performed in a finite cubic lattice. Inside this box, domains with different density coexist, from which clusters of nucleons eventually emerge. Within our approach, the isotopic distributions are determined by the N/Z ratio of the leading unstable isoscalar-like modes and by isovector-like fluctuations present in the matter undergoing the spinodal decomposition. Hence the average value of the N/Z ratio of clusters and the width of the relative distribution reflect the properties of the symmetry energy. By generating a large number of events, these calculations allow a careful investigation of the cluster isotopic content as a function of the cluster density. A uniform decrease of the average charge asymmetry and of the width of the isotopic distributions with increasing density is observed. Finally, we remark that the results essentially refer to the early breakup of the system.

Colonna, M.; Matera, F. [Laboratori Nazionali del Sud, Via S. Sofia 62, I-95123 Catania (Italy); Dipartimento di Fisica, Universita degli Studi di Firenze and Istituto Nazionale di Fisica Nucleare, Sezione di Firenze, Via G. Sansone 1, I-50019 Sesto Fiorentino (Firenze) (Italy)

2008-06-15

4

Density dependence of isospin observables in spinodal decomposition  

NASA Astrophysics Data System (ADS)

Isotopic fluctuations in fragment formation are investigated in a quasianalytical description of the spinodal decomposition scenario. By exploiting the fluctuation-dissipation relations the covariance matrix of density fluctuations is derived as a function of the wave vector k for nuclear matter at given values of density, charge asymmetry, temperature, and the time that the system spends in the instability region. Then density fluctuations in ordinary space are implemented with a Fourier transform performed in a finite cubic lattice. Inside this box, domains with different density coexist, from which clusters of nucleons eventually emerge. Within our approach, the isotopic distributions are determined by the N/Z ratio of the leading unstable isoscalar-like modes and by isovector-like fluctuations present in the matter undergoing the spinodal decomposition. Hence the average value of the N/Z ratio of clusters and the width of the relative distribution reflect the properties of the symmetry energy. By generating a large number of events, these calculations allow a careful investigation of the cluster isotopic content as a function of the cluster density. A uniform decrease of the average charge asymmetry and of the width of the isotopic distributions with increasing density is observed. Finally, we remark that the results essentially refer to the early breakup of the system.

Colonna, M.; Matera, F.

2008-06-01

5

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

6

High resolution electron microscopy of the early decomposition stage of Al-Li alloys  

SciTech Connect

The early decomposition stages of Al-7.8at.%Li, Al-10.4at%Li and Al-11.8at%Li alloys were studied by high resolution electron microscopy. In all the above alloys, it was confirmed that in the as-quenched stage small ordered domains of Ll{sub 2} structure were present surrounded by the disordered matrix. From this microstructure, it was concluded that the alloy was already decomposed as in the as-quenched stage. No clear evidence was found for congruent ordering which was proposed to occur prior to spinodal decomposition. Examination of the sublattices of the individual ordered domains also failed to give convincing evidence for congruent ordering. The present observations suggest that the kinetics of spinodal decomposition of this system is too fast to be detected by TEM. In order to slow down the decomposition kinetics, solution treated samples were quenched to just above the solvus line for {delta}{prime} and then to room temperature. By this heat treatment, a solution treated sample with much weaker order spots could be obtained. However, this microstructure could not be interpreted as congruently ordered either based on the weak Ll{sub 2} spots. As there is a limitation to the quenching speed, it is suggested that ordering and spinodal decomposition progress concomitantly during the observable range of time.

Schmitz, G.; Hono, K.; Haasen, P. [Inst. fur Metallphysik der Univ. Gottingen and SFB (Germany)

1994-01-01

7

Early Universe Observations with TMT  

NASA Astrophysics Data System (ADS)

Time evolution of our universe can be probed directly by observing objects at very high redshifts. In near future we will be able to have a detailed observations of high redshift galaxies and Intergalactic medium thanks to large collecting area and high spatial resolution capabilities of Tirty meter telescope, In this talk I will review various observational programmes with TMT that can allow us to uncover the early universe in detail.

Srianand, Raghunathan

2012-07-01

8

Early stage litter decomposition rates for Swiss forests  

Microsoft Academic Search

The decomposition of belowground and aboveground tree litter was studied on five forest sites across Switzerland, ranging from 480 to 1500 m in altitude, and including calcareous and acidic soils. In addition to decomposition of local litter types (Picea abies, Fagus sylvatica, Castanea sativa), the decomposition of a standard beech litter was studied on all sites. After 2 years of decomposition,

Alexander Heim; Beat Frey

2004-01-01

9

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

10

High resolution electron microscopy of the early decomposition stage of Al-Li alloys  

Microsoft Academic Search

The early decomposition stages of Al-7.8at.%Li, Al-10.4at%Li and Al-11.8at%Li alloys were studied by high resolution electron microscopy. In all the above alloys, it was confirmed that in the as-quenched stage small ordered domains of Llâ structure were present surrounded by the disordered matrix. From this microstructure, it was concluded that the alloy was already decomposed as in the as-quenched stage.

G. Schmitz; K. Hono; P. Haasen

1994-01-01

11

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

12

Changes in the quality of chromophoric dissolved organic matter leached from senescent leaf litter during the early decomposition.  

PubMed

Chromophoric dissolved organic matter (CDOM) leached from leaf litter is a major source of humus in mineral soil of forest ecosystems. While their functions and refractoriness depend on the physicochemical structure, there is little information on the quality of CDOM, especially for that leached in the very early stages of litter decomposition when a large amount of dissolved organic matter (DOM) is leached. This study aimed to better understand the variations/changes in the composition of CDOM leached from senescent leaf litter from two tree species during the early stage of decomposition. Leaf litter from a conifer tree (Japanese cedar, D. Don) and a deciduous broad-leaved tree (Konara oak, Thunb.) were incubated in columns using simulated rainfall events periodically for a total of 300 d at 20°C. The quality of CDOM was investigated based on the fluorescence properties by using a combination of excitation-emission matrix fluorescence (EEM) and parallel factor analysis (PARAFAC). In addition, the phenolic composition of DOM was investigated at a molecular level by thermally assisted hydrolysis and methylation-gas chromatography-mass spectrometry (THM-GC-MS) in the presence of tetramethylammonium hydroxide (TMAH). The EEM was statistically decomposed into eight fluorescence components (two tannin/peptide-like peaks, one protein-like peak, and five humic-like peaks). A significant contribution of tannin/peptide-like peaks was observed at the beginning of incubation, but these peaks decreased quickly and humic-like peaks increased within 1 mo of incubation. The composition of humic-like peaks was different between tree species and changed over the incubation period. Since tannin-derived phenolic compounds were detected in the DOM collected after 254 d of incubation on THM-GC-MS, it was suggested that tannins partially changed its structure, forming various humic-like peaks during the early decomposition. PMID:22565264

Nishimura, Satoshi; Maie, Nagamitsu; Baba, Mitsuhisa; Sudo, Takahiro; Sugiura, Toshihiro; Shima, Eikichi

13

Bain strain relaxation during early stage decomposition of a hyper-eutectoid CuBe alloy  

SciTech Connect

Decomposition of a hyper-eutectoid [beta] (b.c.c.) phase CuBe alloy into the two phase [[gamma](B2) + [alpha](f.c.c.)] mixed involves composition separation, b.c.c. to B2 atomic ordering and b.c.c. to f.c.c. crystal lattice rearrangement. In this investigation, the relaxation of the Bain transformation strain associated with the b.c.c. to f.c.c. lattice rearrangement is studied by TEM during the early stages of decomposition and experimental findings are interpreted within the framework of an elasticity theory of plate-like precipitates. The authors have found that relaxation of the Bain strain proceeds gradually with the advancement of decomposition. A decomposition sequence which is consistent with the microstructures is: b.c.c. to B2 ordering [r arrow] isostructural secondary decomposition and the formation of [001] plate-like G.P. zones (b.c.t) [r arrow] b.c.c. to f.c.c. crystal lattice rearrangement and the formation of plate-like [alpha][prime] (f.c.t.) precipitates with [001] habit planes [r arrow] gradual relaxation to [alpha] (f.c.c.) phase. From habit plane stability analysis, they demonstrate that the intermediate [alpha][prime] (f.c.t.) state is elastically unstable. Driven by this instability, the relaxation was found to occur mainly through the interplay of two basic mechanisms, that is, habit rotation and the formation of polytwin morphology. The interplay was manifested in the form of characteristic saw-tooth type polytwin plates. From a careful analysis of as-quenched states, they have found that the formation of the saw-tooth morphology initiates by plate intersection through the formation of stacking faults. They have explained this in terms of a dislocation model.

Cheong, B.; Laughlin, D.E. (Carnegie Mellon Univ., Pittsburgh, PA (United States). Dept. of Materials Science and Engineering); Hono, K. (Tohoku Univ., Sendai (Japan). Inst. for Materials Research)

1994-07-01

14

Early post-mortem changes and stages of decomposition in exposed cadavers  

Microsoft Academic Search

Decomposition of an exposed cadaver is a continuous process, beginning at the moment of death and ending when the body is\\u000a reduced to a dried skeleton. Traditional estimates of the period of time since death or post-mortem interval have been based\\u000a on a series of grossly observable changes to the body, including livor mortis, algor mortis, rigor mortis and similar

M. Lee Goff

2009-01-01

15

SCUBA OBSERVATIONS OF EARLY-TYPE GALAXIES  

SciTech Connect

We present SCUBA observations of the emission of 23 E and S0 galaxies at wavelengths of 850 and 450 mum. Four galaxies are detected at 850 mum with signal-to-noise ratios above 3.0, and an additional galaxy, NGC 6524, is detected at both 850 and 450 mum. We use the SCUBA data with published optical and IRAS photometry to construct spectral energy distributions (SEDs) of 15 galaxies extending from 0.36 to 850 mum. Those SEDs are fit by single-temperature dust emission models and by predictions generated by self-consistent Monte Carlo simulations of radiative transfer in three-dimensional distributions of stars and diffuse dust. We discuss implications for the question of cool dust in early-type galaxies, the spatial distribution of diffuse dust, and its ability to generate optical color gradients.

Savoy, Jonathan; Welch, Gary A. [Saint Mary's University, Department of Astronomy and Physics, Halifax, Nova Scotia B3H 3C3 (Canada); Fich, Michel, E-mail: jsavoy@ap.stmarys.c, E-mail: gwelch@ap.stmarys.c, E-mail: fich@astro.uwaterloo.c [University of Waterloo, Department of Physics and Astronomy, Waterloo, Ontario (Canada)

2009-11-20

16

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

17

In situ TEM observation of the growth and decomposition of monoclinic W(18)O(49) nanowires.  

PubMed

The growth of monoclinic W(18)O(49) nanowires by heat treatment of a tungsten filament at approximately 873 K and the decomposition of these nanowires under 200 keV electron irradiation at approximately 1023 K have been investigated using in situ transmission electron microscopy (TEM). In situ TEM observation of the growth confirmed the vapor-solid growth mechanism of the monoclinic W(18)O(49) nanowires. In situ irradiation experiments revealed the formation of metallic bcc tungsten from monoclinic W(18)O(49) nanowires under 200 keV electron irradiation. PMID:19550017

Chen, C L; Mori, H

2009-06-24

18

In situ TEM observation of the growth and decomposition of monoclinic W18O49 nanowires  

NASA Astrophysics Data System (ADS)

The growth of monoclinic W18O49 nanowires by heat treatment of a tungsten filament at ~873 K and the decomposition of these nanowires under 200 keV electron irradiation at ~1023 K have been investigated using in situ transmission electron microscopy (TEM). In situ TEM observation of the growth confirmed the vapor-solid growth mechanism of the monoclinic W18O49 nanowires. In situ irradiation experiments revealed the formation of metallic bcc tungsten from monoclinic W18O49 nanowires under 200 keV electron irradiation.

Chen, C. L.; Mori, H.

2009-07-01

19

Effects of litter manipulation on early-stage decomposition and meso-arthropod abundance in a tropical moist forest  

Microsoft Academic Search

Differences in forest productivity due to climate change may result in permanently altered levels of litterfall and litter on the forest floor. Using experimental litter removal and litter addition treatments, we investigated the effects of increased and decreased litterfall on early-stage litter decomposition and the abundance of meso-arthropods in a moist tropical forest. Litterbags containing freshly fallen leaves of Cecropia

E. J. Sayer; E. V. J. Tanner; A. L. Lacey

2006-01-01

20

Unimolecular thermal decomposition of phenol and d5-phenol: direct observation of cyclopentadiene formation via cyclohexadienone.  

PubMed

The pyrolyses of phenol and d(5)-phenol (C(6)H(5)OH and C(6)D(5)OH) have been studied using a high temperature, microtubular (?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 ?tubular reactor of approximately 50-100 ?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(6)H(5)OH ? c-C(6)H(6) = O ? c-C(5)H(6) + CO. The cyclopentadiene loses a H atom to generate the cyclopentadienyl radical which further decomposes to acetylene and propargyl radical; c-C(5)H(6) ? c-C(5)H(5) + H ? HC?CH + HCCCH(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(6)H(5)O-H ? C(6)H(5)O + H ? c-C(5)H(5) + CO. The direct decarbonylation reaction remains an important channel in the thermal decomposition mechanisms of the dihydroxybenzenes. Both catechol (o-HO-C(6)H(4)-OH) and hydroquinone (p-HO-C(6)H(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. PMID:22299873

Scheer, Adam M; Mukarakate, Calvin; Robichaud, David J; Nimlos, Mark R; Carstensen, Hans-Heinrich; Ellison, G Barney

2012-01-28

21

Unimolecular thermal decomposition of phenol and d5-phenol: Direct observation of cyclopentadiene formation via cyclohexadienone  

NASA Astrophysics Data System (ADS)

The pyrolyses of phenol and d5-phenol (C6H5OH and C6D5OH) have been studied using a high temperature, microtubular (?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 ?tubular reactor of approximately 50-100 ?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; C6H5OH --> c-C6H6 = O --> c-C5H6 + CO. The cyclopentadiene loses a H atom to generate the cyclopentadienyl radical which further decomposes to acetylene and propargyl radical; c-C5H6 --> c-C5H5 + H --> HC?CH + HCCCH2. 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; C6H5O-H --> C6H5O + H --> c-C5H5 + CO. The direct decarbonylation reaction remains an important channel in the thermal decomposition mechanisms of the dihydroxybenzenes. Both catechol (o-HO-C6H4-OH) and hydroquinone (p-HO-C6H4-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, Adam M.; Mukarakate, Calvin; Robichaud, David J.; Nimlos, Mark R.; Carstensen, Hans-Heinrich; Barney Ellison, G.

2012-01-01

22

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

PubMed

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 spectrometry (TD/GC/MS). Over 30 substances were identified in total. These included mainly aliphatic and aromatic hydrocarbons, oxygenated compounds (alcohols, aldehydes, ketones) and organic sulfides. The last were the most prominent class of compounds identified. Eleven compounds were present in all the sampling cycles and constitute a "common core": ethanol, 2-propanone, dimethyl disulfide, methyl benzene, octane, 2-butanone, methyl ethyl disulfide, dimethyl trisulfide and o-, m- and p-xylenes. The last sampling cycle yielded the most abundant compounds in number and quantities. Inorganic gases such as CO2, CO, NH3 and H2S were also determined. The fundamental physicochemical properties of the evolved VOCs were used for evaluating their environmental impacts. It appears that the decay process, which is a dynamic procedure, can provide chemical signals that might be detected and properly evaluated by experts in the fields of forensic sciences, search and rescue units and environmental scientists. PMID:17669473

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

2007-07-31

23

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

24

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

Microsoft Academic Search

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,

Stephen Opsahl; Ronald Benner

1995-01-01

25

Indium hydroxide to oxide decomposition observed in one nanocrystal during in situ transmission electron microscopy studies  

NASA Astrophysics Data System (ADS)

The high-resolution transmission electron microscopy (HR-TEM) is used to study, in situ, spatially resolved decomposition in individual nanocrystals of metal hydroxides and oxyhydroxides. This case study reports on the decomposition of indium hydroxide (c-In(OH)3) to bixbyite-type indium oxide (c-In2O3). The electron beam is focused onto a single cube-shaped In(OH)3 crystal of {100} morphology with ca. 35 nm edge length and a sequence of HR-TEM images was recorded during electron beam irradiation. The frame-by-frame analysis of video sequences allows for the in situ, time-resolved observation of the shape and orientation of the transformed crystals, which in turn enables the evaluation of the kinetics of c-In2O3 crystallization. Supplementary material (video of the transformation) related to this article can be found online at 10.1016/j.jssc.2012.09.022. After irradiation the shape of the parent cube-shaped crystal is preserved, however, its linear dimension (edge) is reduced by the factor 1.20. The corresponding spotted selected area electron diffraction (SAED) pattern representing zone [001] of c-In(OH)3 is transformed to a diffuse strongly textured ring-like pattern of c-In2O3 that indicates the transformed cube is no longer a single crystal but is disintegrated into individual c-In2O3 domains with the size of about 5-10 nm. The induction time of approximately 15 s is estimated from the time-resolved Fourier transforms. The volume fraction of the transformed phase (c-In2O3), calculated from the shrinkage of the parent c-In(OH)3 crystal in the recorded HR-TEM images, is used as a measure of the kinetics of c-In2O3 crystallization within the framework of Avrami-Erofeev formalism. The Avrami exponent of ˜3 is characteristic for a reaction mechanism with fast nucleation at the beginning of the reaction and subsequent three-dimensional growth of nuclei with a constant growth rate. The structural transformation path in reconstructive decomposition of c-In(OH)3 to c-In2O3 is discussed in terms of (i) the displacement of hydrogen atoms that lead to breaking the hydrogen bond between OH groups of [In(OH)6] octahedra and finally to their destabilization and (ii) transformation of the vertices-shared indium-oxygen octahedra in c-In(OH)3 to vertices- and edge-shared octahedra in c-In2O3.

Miehe, Gerhard; Lauterbach, Stefan; Kleebe, Hans-Joachim; Gurlo, Aleksander

2013-02-01

26

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

27

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

28

Implications of early time observations of optical afterglows of GRBs  

NASA Astrophysics Data System (ADS)

Optical observations of afterglows at very times are very useful towards understanding the least known problem of GRB research field i.e. the transition from prompt emission to early afterglows. The comparison of a subset of well-monitored GRBs and their early time properties at optical are compared with that seen at XRT and BAT wavelengths. In most of the observed cases, the very early optical observations of GRBs do not trace the canonical decay nature seen at XRT wavelengths, suggesting different origins for the observed early emissions in the two bands. In some of the early optical light-curves, the decay followed by smooth rise features are consistent with the onset of the afterglow although such features are also expected if the emission is seen off-axis and/or the outflow is structured.

Pandey, S. B.; Zheng, W.

2013-07-01

29

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

30

Study of recognizing human motion observed from an arbitrary viewpoint based on decomposition of a tensor containing multiple view motions  

Microsoft Academic Search

We propose a Tensor Decomposition based algorithm that recognizes the observed action performed by an unknown person and unknown viewpoint not included in the database. Our previous research aimed motion recognition from one single viewpoint. In this paper, we extend our approach for human motion recognition from an arbitrary viewpoint. To achieve this issue, we set tensor database which are

Takayuki Hori; Jun Ohya; Jun Kurumisawa

2011-01-01

31

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

P. J. Moran

1992-01-01

32

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

33

Direct observation of roaming radicals in the thermal decomposition of acetaldehyde.  

SciTech Connect

The thermal dissociation of acetaldehyde has been studied with the reflected shock tube technique using H(D)-atom atomic resonance absorption spectrometry detection. The use of an unreversed light source yields extraordinarily sensitive H atom detection. As a result, we are able to measure both the total decomposition rate and the branching to radical versus molecular channels. This branching provides a direct measure of the contribution from the roaming radical mechanism since the contributions from the usual tight transition states are predicted by theory to be negligible. The experimental observations also provide a measure of the rate coefficient for H + CH{sub 3}CHO. Another set of experiments employing C{sub 2}H{sub 5}I as an H-atom source provides additional data for this rate coefficient that extends to lower temperature. An evaluation of the available experimental results for H + CH{sub 3}CHO can be expressed by a three-parameter Arrhenius expression as k = 7.66 x 10{sup -20}T{sup 2.75} exp((-486 K)/T) cm{sup 3} molecule{sup -1} s{sup -1} (298-1415 K). Analogous experiments employing C{sub 2}D{sub 5}I as a D-atom source allow for the study of the isotopically substituted reaction. The present experiments are the only direct measure for this reaction rate constant, and the results can be expressed by an Arrhenius expression as k = 5.20 x 10{sup -10} exp((-4430 K)/T) cm{sup 3} molecule{sup -1} s{sup -1} (1151-1354 K). The H/D + CH{sub 3}CHO reactions are also studied with ab initio transition-state theory, and the results are in remarkably good agreement with the current experimental data.

Sivaramakrishnan, R.; Michael, J. V.; Klippenstein, S. J.; Chemical Sciences and Engineering Division

2010-01-21

34

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

NASA Astrophysics Data System (ADS)

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 the remains could be recognised as crown-of-thorns starfish for up to 5 days. The reason for the sudden disappearance of starfish at the ends of outbreaks is briefly discussed.

Moran, P. J.

1992-07-01

35

Lick Adaptive Optics Observations of Early-Type Galaxy Centers  

Microsoft Academic Search

We have observed the centers of 10 nearby early-type galaxies using the Lick Adaptive Optics (AO) system in the H-band. The Lick AO system gives us near diffraction-limited performance in the H-band with a resolution of 0.\\

L. M. Raschke; P. Jonsson; S. Severson; S. M. Faber; B. A. Macintosh

2000-01-01

36

Direct observation and quantification of nanoscale spinodal decomposition in super duplex stainless steel weld metals.  

PubMed

Three variants of super duplex stainless steel weld metals with the basic composition 29Cr-8Ni-2Mo (wt%) were investigated. The nitrogen content of the three materials was 0.22%, 0.33% and 0.37%, respectively. Isothermal heat treatments were performed at 450 degrees C for times up to 243 h. The hardness evolution of the three materials was found to vary with the overall concentration of the nitrogen. Atom probe field ion microscopy (APFIM) was used to directly detect and quantify the degree of spinodal decomposition in different material conditions. 3-DAP atomic reconstruction clearly illustrate nanoscale variation of iron rich (alpha) and chromium rich (alpha') phases. A longer ageing time produces a coarser microstructure with larger alpha and alpha' domains. Statistical evaluation of APFIM data showed that phase separation was significant already after 1 h of ageing that gradually became more pronounced. Although nanoscale concentration variation was evident, no significant influence of overall nitrogen content on the degree of spinodal decomposition was found. PMID:19504899

Shariq, Ahmed; Hättestrand, Mats; Nilsson, Jan-Olof; Gregori, Andrea

2009-06-01

37

Using soil enzymes to explain observed differences in the response of soil decomposition to nitrogen fertilization  

NASA Astrophysics Data System (ADS)

Soil microbes produce extracellular enzymes that degrade a variety of carbon-rich polymers contained within soil organic matter (SOM). These enzymes are key regulators of the terrestrial carbon cycle. However, basic information about the kinetics of extracellular enzymes and key environmental variables that regulate their catalytic ability is lacking. This study aims to clarify the mechanisms by which microbial carbon-degrading enzymes drive different responses to nitrogen (N) fertilization in soil decomposition at two sites with long-term N fertilization experiments, the Bear Brook (BB) forest in Maine and Fernow Forest (FF) in West Virginia. We examined a suite of cellulolytic and lignolytic enzymes that break down common SOM constituents. We hypothesized that enzymes derived from the site with a higher mean annual temperature (FF) would be more heat-tolerant, and retain their catalytic efficiency (Km) as temperature rises, relative to enzymes from the colder environment (BB). We further hypothesized that cellulolytic enzyme activity would be unaffected by N, while oxidative enzyme activity would be suppressed in N-fertilized soils. To test these hypotheses and examine the interactive effects of temperature and N, we measured enzyme activity in unfertilized and N-fertilized soils under a range of laboratory temperature manipulations. Preliminary results show a significant decrease in cellulolytic enzyme efficiency with temperature at the colder site (BB), as well as a significant increase in efficiency due to N-fertilization for two cellulolytic enzymes. Oxidative enzyme activity shows a marginally significant reduction due to N-fertilization at BB. These results suggest that soil warming may produce a negative feedback on carbon turnover in certain climates, while N-fertilization may alter the relative decomposition rates of different soil organic matter constituents. FF activity will be analyzed in a similar manner and the two sites will be compared in order to fully assess our hypotheses.

Stone, M.; Weiss, M.; Goodale, C. L.

2010-12-01

38

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...

39

The cosmic microwave background: observing directly the early universe  

NASA Astrophysics Data System (ADS)

The Cosmic Microwave Background (CMB) is a relict of the early universe. Its perfect 2.725K blackbody spectrum demonstrates that the universe underwent a hot, ionized early phase; its anisotropy (about 80 µK rms) provides strong evidence for the presence of photon-matter oscillations in the primeval plasma, shaping the initial phase of the formation of structures; its polarization state (about 3 µK rms), and in particular its rotational component (less than 0.1 µK rms) might allow to study the inflation process in the very early universe, and the physics of extremely high energies, impossible to reach with accelerators. The CMB is observed by means of microwave and mm-wave telescopes, and its measurements drove the development of ultra-sensitive bolometric detectors, sophisticated modulators, and advanced cryogenic and space technologies. Here we focus on the new frontiers of CMB research: the precision measurements of its linear polarization state, at large and intermediate angular scales, and the measurement of the inverse-Compton effect of CMB photons crossing clusters of Galaxies. In this framework, we will describe the formidable experimental challenges faced by ground-based, near-space and space experiments, using large arrays of detectors. We will show that sensitivity and mapping speed improvement obtained with these arrays must be accompanied by a corresponding reduction of systematic effects (especially for CMB polarimeters), and by improved knowledge of foreground emission, to fully exploit the huge scientific potential of these missions.

de Bernardis, Paolo; Masi, Silvia

2012-09-01

40

Early decomposition in visual word recognition: Dissociating morphology, form, and meaning  

PubMed Central

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 relatedness were presented at three SOAs (36, 48, and 72 ms). No effects of orthographic relatedness were found at any SOA. Semantic relatedness did not interact with effects of morphological decomposability, which came through strongly at all SOAs, even for pseudo-suffixed pairs such as archer-arch. Derivational morphological effects in masked priming seem to be primarily driven by morphological decomposability at an early stage of visual word recognition, and are independent of semantic factors. A second experiment reversed the order of prime and target (stem-derived rather than derived-stem), and again found that morphological priming did not interact with semantic relatedness. This points to an early segmentation process that is driven by morphological decomposability and not by the structure or content of central lexical representations.

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

2008-01-01

41

Cold Dust in Early-Type Galaxies: Observations and modeling.  

NASA Astrophysics Data System (ADS)

We report results from our search for far-ir dust emission in early-type galaxies, using the array photometer on board the ISO satellite. A total of about 25 elliptical galaxies have observed with ISOPHOT, using both the sparse map mode and the "P32" Astronomical Observing Template (AOT) oversampled map in which the sky is mapped at high redundancy and with a sampling approaching the Nyquist limit. A significant fraction of observed galaxies have been detected at 60, 100, and 180 ? m showing evidence that these galaxies contain cold interstellar dust. Assuming that the circumstellar dust observed at mid-ir wavelengths in many ellipticals, ultimately becomes interstellar, we have computed the temperature profile and far-infrared spectrum for appropriate models of elliptical galaxies. In these models, dust grains are heated by both absorption of starlight and by electron-grain collision and are sputtered away by the interaction with the hot gas. The interpretation of the observations with the theoretical models allow us to put some constrains on the physical properties of the interstellar dust, its origin and distribution.

Temi, Pasquale; Mathews, William G.; Brighenti, Fabrizio; Bregman, Jesse D.

42

Early and late motor responses to action observation.  

PubMed

Is a short visuomotor associative training sufficient to reverse the visuomotor tuning of mirror neurons in adult humans? We tested the effects of associative training on corticospinal modulation during action observation in the 100-320?ms interval after action onset. In two separate experiments, the acceleration of transcranial magnetic stimulation (TMS)-induced movements was recorded before and after training participants to respond to observed acts with an opposite or similar behavior. Before training, TMS-induced accelerations mirrored the observed action at 250 and 320?ms. After training, responses at 250?ms were unchanged and still mirrored the stimuli, without any effect of training direction. Only at 320?ms, we observed training-dependent changes in evoked responses. A control experiment with non-biological rotational movements as visual stimuli indicated that spatial stimulus-response compatibility is not sufficient to account for the results of the two main experiments. We show that the effects of a short visuomotor associative training are not pervasive on the automatic mirror responses. 'Early' (250?ms) responses were not influenced by training. Conversely only 'late' (320?ms) responses changed according to the training direction. This biphasic time course indicates that two distinct mechanisms produce the automatic mirror responses and the newly learned visuomotor associations. PMID:22563004

Barchiesi, Guido; Cattaneo, Luigi

2012-05-03

43

Early stages of spinodal decomposition for the Cahn-Hilliard-Cook model of phase separation  

NASA Astrophysics Data System (ADS)

A computer simulation using discretized space and time is employed to examine the early stages of phase separation as described by the Cahn-Hilliard-Cook equation (CHCE). The relative simplicity of this simulation provides a direct test of various mathematical treatments of the nonlinear term in the CHCE. In particular, the numerical results are used to ascertain the validity of the approximations inherent in the perturbative expansions of Grant, San Miguel, Vinals, and Gunton, and of Langer, Bar-on, and Miller. The time of validity of all approximations is shown to be logarithmically related to the strength of the thermal fluctuations. In addition, the effect of the initial state on the dynamical evolution of the order parameter is examined.

Elder, K. R.; Rogers, T. M.; Desai, Rashmi C.

1988-09-01

44

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

45

Observational and Numerical Constraints on Early Star Cluster Evolution  

NASA Astrophysics Data System (ADS)

Exciting recent developments in theory and observations call for renewed scrutiny of the early evolution of star clusters spanning a large range of parameter space. First, using a large ensemble of N-body simulations of moderately sized (N=1000), cool, fractal clusters, we find that cool, clumpy clusters dynamically mass segregate on a short timescale. This implies that the notion of ‘primordial mass segregation’ may be obsolete. The cluster properties also change rapidly on very short timescales: young clusters may undergo core collapse on timescales of < 1 Myr, when a dense core containing massive stars is hardened because of energy losses to a halo of lower-mass stars. In addition, we use high-resolution Hubble Space Telescope imaging observations of the young ( 15-25 Myr-old) star cluster NGC 1818 in the Large Magellanic Cloud to derive an estimate for the binary fraction of F stars (1.3 < m*/M¤ 1.6). Our new study provides the strongest constraints yet on the (close to) initial binary fraction in a low-metallicity environment ([Fe/H] -0.4 dex). We find that our novel artificial-star-test method is sensitive to binaries with mass ratios, q? 0.4. For binaries with F-star primaries and mass ratios q> 0.4, the binary fraction is 0.35. This suggests a total binary fraction for F stars of 0.55 to unity, depending on assumptions about the form of the mass-ratio distribution at low q, which is consistent with the field and lower-density clusters. This suggests that, at least among intermediate-mass stars, metallicity down to [Fe/H] -0.4 dex does not suppress fragmentation and binary formation, and the binarity of these stars is at least as high as at solar metallicity. We therefore strongly argue for inclusion of realistic binary fractions in simulations aimed at following early star cluster evolution.

de Grijs, Richard; Allison, R. J.; Hu, Y.; Deng, L.; Goodwin, S. P.

2011-01-01

46

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

47

"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…

Nyland, Berenice; Alfayez, Shatha

2012-01-01

48

Interface formation during spinodal decomposition  

SciTech Connect

Already Swanger, Gupta, and Cooper have shown that the nonlinear term in the differential equation that describes spinodal decomposition is responsible for the decomposition going to completion. We contend that the term is also responsible for the decomposition going to completion. We contend that the term is also responsible for the formation of sharp interfaces relatively early in the decomposition process. There is experimental verification of this.

Williams, R.O.

1981-01-01

49

Observation of nanoparticle formation process by two-dimensional laser-induced fluorescence, UV Rayleigh scattering, and re-decomposition laser-induced fluorescence methods  

Microsoft Academic Search

We have investigated the formation process of nanoparticles in the laser ablation plume by different laser imaging spectroscopy techniques, such as Two-Dimensional laser induced fluorescence (2D-LIF), UV Rayleigh scattering (UV- RS), and Re-Decomposition LIF (ReD-LIF). Clusters, which are hardly observed by the UV-RS method due to their small size, are observed by the ReD-LIF method. The dynamics and formation processes

Junichi Muramoto; Takahiro Inmaru; Yoshiki Nakata; Tatsuo Okada; Mitsuo Maeda

2000-01-01

50

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

51

Prescriptive Early Intervention With Culturally Diverse Populations: Some Initial Observations.  

ERIC Educational Resources Information Center

|The Social Skills Development Program (SSDP) is a prevention program for inner-city primary-age school children. The services provided by SSDP are for children experiencing moderate school maladjustment. Included are descriptions of program rationale and operations, staffing, prescriptive early intervention, preventive health interventions and…

Handy, Walter S.; Pedro-Carroll, JoAnne

52

X-ray Scattering Study of Early Stage Spinodal Decomposition in Al{sub 0.62}Zn{sub 0.38}  

SciTech Connect

{ital In situ} small-angle x-ray scattering studies of the spinodal decomposition kinetics in an AlZn alloy at the critical composition have been performed with a time resolution of 10ms. The kinetics of fluctuation relaxation above the critical point merges smoothly with the early-stage kinetics of fluctuation growth below T{sub c}. Strong nonlinearities are present at the earliest times measured, even above the critical point. The nonlinear theory of Langer, Bar-on, and Miller [Phys.Rev.A {bold 11}, 1417 (1975)] quantitatively fits the data with reasonable thermodynamic and transport parameters. {copyright} {ital 1997} {ital The American Physical Society}

Mainville, J.; Yang, Y.; Elder, K.; Sutton, M. [Centre for the Physics of Materials and Department of Physics, McGill University, Montreal, H3A 2T8 (CANADA); Ludwig, K. Jr.; Stephenson, G. [IBM Research Division, Thomas J. Watson Research Center, Yorktown Heights, New York 10598 (United States)

1997-04-01

53

The Swift XRT: Observations of Early X-ray Afterglows  

SciTech Connect

During the first year of operations of the Swift observatory, the X-ray Telescope has made a number of discoveries concerning the nature of X-ray afterglows of both long and short GRBs. We highlight the key findings, which include rapid declines at early times, a standard template of afterglow light curve shapes, common flaring, and the discovery of the first short GRB afterglow.

Burrows, David N.; Kennea, J. A.; Nousek, J. A. [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States); Osborne, J. P.; O'Brien, P. T. [Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH (United Kingdom); Chincarini, G. [INAF-Osservatorio Astronomico di Brera, Via Bianchi 46, 23807 Merate (Italy); Universita degli studi di Milano-Bicocca, Piazza delle Scienze 3, 20126 Milan (Italy); Tagliaferri, G. [INAF-Osservatorio Astronomico di Brera, Via Bianchi 46, 23807 Merate (Italy); Giommi, P. [ASI Science Data Center, via Galileo Galilei, 00044 Frascati (Italy); Zhang, B. [Department of Physics, University of Nevada, Box 454002, Las Vegas, NV 89154-4002 (United States)

2006-05-19

54

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

55

Innovation in observation: a vision for early outbreak detection  

PubMed Central

The emergence of new infections and resurgence of old ones—health threats stemming from environmental contamination or purposeful acts of bioterrorism—call for a worldwide effort in improving early outbreak detection, with the goal of ameliorating current and future risks. In some cases, the problem of outbreak detection is logistically straightforward and mathematically easy: a single case of a disease of great concern can constitute an outbreak. However, for the vast majority of maladies, a simple analytical solution does not exist. Furthermore, each step in developing reliable, sensitive, effective surveillance systems demonstrates enormous complexities in the transmission, manifestation, detection, and control of emerging health threats. In this communication, we explore potential future innovations in early outbreak detection systems that can overcome the pitfalls of current surveillance. We believe that modern advances in assembling data, techniques for collating and processing information, and technology that enables integrated analysis will facilitate a new paradigm in outbreak definition and detection. We anticipate that moving forward in this direction will provide the highly desired sensitivity and specificity in early detection required to meet the emerging challenges of global disease surveillance.

Fefferman, NH; Naumova, EN

2010-01-01

56

Observations of the temporal variation in chemical content of decomposition fluid: A preliminary study using pigs as a model system  

Microsoft Academic Search

In this paper we report the results of our preliminary studies into short chain fatty acids that have the potential to show reproducible patterns over certain postmortem intervals during decomposition in the absence of a soil matrix. Additional compounds that were detected, including several long chain fatty acids, were also investigated for their potential in estimating postmortem interval. Analysis of

Lisa Swann; Shari Forbes; Simon W. Lewis

2010-01-01

57

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

58

Early Radar Observations of Asteroid 2012 DA14  

NASA Video Gallery

This 73-frame movie of asteroid 2012 DA14 was generated from data obtained by NASA's Goldstone Solar System Radar on the night of Feb. 15 to 16, 2013. The observations were made as the asteroid was moving away from Earth. Image credit: NASA/JPL-Caltech › Asteroid and Comet Watch site

Anthony Greicius

2013-02-19

59

Bradycardia and hypotension during spinal anesthesia: early observations  

Microsoft Academic Search

Soon after spinal anesthesia was introduced, surgeons became aware of the eventual occurrence of bradycardia and hypotension. However, the measurement of blood pressure was not a routine practice. The usual clinical observation consisted of palpation of the pulse for estimation of its fullness and for counting its rate. Therefore, it took a few years for the complete description of the

Carlos Parsloe

2002-01-01

60

Observational Measures of Auditory Sensitivity in Early Infancy.  

ERIC Educational Resources Information Center

|A modification of the observer-based psychoacoustic procedure was used to estimate the detectability of auditory signals by infants. Data from infants up to 3.5 months of age revealed improvement in performance as a function of increasing signal intensity and age. (BC)|

Trehub, Sandra E.; And Others

1991-01-01

61

Feeding behaviour and phylogeny: observations on early derivative Acari  

Microsoft Academic Search

Based on laboratory observations of three species of Allothyrus (Parasitiformes: Holothyrida: Allothyridae) from south east Queensland and gut content analysis of 62 individuals representing 11 species of Allothyrus from eastern Australia, we determined that Australian Allothyridae are scavengers that ingest fluids only. Living arthropods, nematodes, snails and annelids were ignored, but dead arthropods were readily fed upon and were sufficient

David Evans Walter; Heather C. Proctor

1998-01-01

62

Early Observations of Saturn Kilometric Radiation by Cassini  

Microsoft Academic Search

One of the primary objectives of the Cassini radio and plasma wave science investigation at Saturn is the study of Saturn kilometric radio emissions (SKR). Based primarily on Voyager observations, these emissions are believed to be analogous to auroral kilometric radiation at Earth, generated via the cyclotron maser instability near the electron cyclotron frequency on field lines threading Saturn's aurora.

W. S. Kurth; G. B. Hospodarsky; D. A. Gurnett; M. D. Desch; M. L. Kaiser; P. Zarka; A. Lecacheux

2002-01-01

63

A study of the human decomposition sequence in central Texas.  

PubMed

Decomposition studies utilizing nonhuman subjects as human analogues are well established, but fewer studies utilizing intact human remains exist. This study provides data from a controlled decomposition study involving human remains in Central Texas. A 63.5-kg unmodified cadaver was placed in an open-air site and observed over a 10-week period from April 11 through June 19, 2008. A wire enclosure restricted scavenger access. State of decomposition and environmental conditions were recorded daily for the first 36 days and then every 2 weeks thereafter. Results indicated a high degree of correlation with other decomposition studies originating in the southwestern United States, although slight deviations for the average duration of early events were noted. The data were also utilized to test a quantitative method for estimating the postmortem interval. Results indicated preliminary support for a quantitative approach. Additional research is encouraged to further establish the human decomposition data set for Central Texas. PMID:20840291

Parks, Connie L

2010-09-14

64

Ammonia adsorption and decomposition on silica supported Rh nanoparticles observed by in situ attenuated total reflection infrared spectroscopy  

Microsoft Academic Search

Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) is applied to study NH3, adsorbed from the gas phase, and its decomposition products, i.e. NHx species, on Rh nanoparticles, produced by spincoating from a RhCl3 solution in water followed by reduction. A silicon ATR crystal with a hydroxilated SiO2 layer acts as the support for the nanoparticles. Upon exposure to NH3

C. M. Leewis; W. M. M. Kessels; J. W. Niemantsverdriet

2006-01-01

65

Direct observation of low-temperature catalytic decomposition of H3BO3 shell in core/shell Ni/H3BO3 nanoparticles  

NASA Astrophysics Data System (ADS)

Decomposition of H3BO3 to B2O3 in core/shell Ni/H3BO3 nanoparticles was in situ recorded by transmission electron microscope as the irradiation time. The direct observation provides compelling evidence of the synergetic effect of the Ni core and the H3BO3 shell, revealing the catalytic mechanisms of metal nanostructures that induce the decomposition at 124 °C, lower than the bulk counterpart at 300 °C. This phenomenon can be theoretically explained by considering the weakening of B-O bond at the Ni-H3BO3 interface, and has important implications in understanding the lubricant behavior of H3BO3 in frictional wear.

Zhang, X. F.; Guan, P. F.; Dong, X. L.

2012-08-01

66

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

67

The measurement of composition during the early stages of the spinodal decomposition of Fe-Cr alloys  

SciTech Connect

The properties of many advanced alloys are derived from extremely fine-scale microstructures. This poses interesting questions about the measurement of composition on this scale. The phase separation of model Fe--Cr alloys has been studied with the atom-probe. Statistical techniques have been used to estimate the composition and compare the results with the predictions of linear and non-linear theories of spinodal decomposition and the distributions obtained from Monte-Carlo calculations. 5 refs., 4 figs., 1 tab.

Hertherington, M.G.; Hyde, J.M. (Oxford Univ. (UK). Dept. of Materials); Miller, M.K. (Oak Ridge National Lab., TN (USA))

1990-01-01

68

Early Observations in the Taiwanese-American Occultation Survey  

NASA Astrophysics Data System (ADS)

The Taiwanese-American Occultation Survey (TAOS) is a program dedicated to performing a survey of the size and number distribution for small bodies (< 10km) in the Kuiper Belt. These objects are too faint to be detected through traditional means, but can be observed via their occultations of background stars. This technique is challenging due to the low event rate, the short event duration (< 200ms), marginal signal to noise of detections, and the possibility of a high false detection rate due to atmospheric fluctuations or other terrestrial phenomena. TAOS overcomes these obstacles with a four robotic telescope array (50cm) located in Lulin, Taiwan. Each telescope is equipped with a 2048 x 2048 pixel CCD camera. All four telescopes synchronously monitor up to 2000 stars autonomously at 5 Hz. We discuss the current state of the survey and the overall performance of the system during predicted asteroid occultations. In particular, we discuss our two telescope response to the occultation by (1723) Klemola of HIP 050535 (V = 8.46), with a maximal duration of 1.3 seconds and 7.2 magnitude drop.

Alcock, C.; Bianco, F.; Lehner, M.; Dave, R.; Giammarco, J.; Schwamb, M.; Cook, K.; Marshall, S.; de Pater, I.; Porrata, R.; Rice, J.; Lissauer, J.; Lee, T.; King, S. K.; Wang, A.; Wang, S. Y.; Wen, C. Y.; Chen, W. P.; Ip, W.; Chang, Y. H.; Kinoshita, D.; Lin, H. C.; Mondal, S.; Zhang, Z. W.; Axelrod, T.; Byun, Y. I.

2005-12-01

69

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.

Brazil-JAPAN Collaboration Of Chacaltaya Emulsion Chamber Experiment; Beggio, P. C.; de Carvalho, A. O.; Chinellato, J. A.; Mariano, A.; de Oliveira, R.; Shibuya, E. H.

2008-01-01

70

Photochemical decomposition of energetic materials: Observation of aryl benzyloxy nitroxide and aryl benzyl nitroxide radicals in solutions of 1,3,5-trinitrobenzene and toluene and their deuteriated analogues at 200 K  

SciTech Connect

Electron spin resonance spectroscopy is used to probe the photodecomposition of 1,3,5-trinitrobenzene (TNB) in toluene. The photodecomposition is conducted at 200 K with solutions containing TNB and toluene along with solutions containing their deuteriated analogues. primary radicals observed in the decomposition have structures consistent with 3,5-dinitrophenyl benzyloxy nitroxide moieties. These radicals are proposed to be precursors to 3,5-dinitrophenyl benzyl nitroxide radicals previously observed in both photochemical and thermal decomposition.

Menapace, J.A.; Marlin, J.E. (Frank J. Seiler Research Lab., USAF Academy, CO (USA))

1990-03-08

71

Depression and anxiety in women with early breast cancer: five year observational cohort study  

Microsoft Academic Search

Objective To examine the prevalence of, and risk factors for, depression and anxiety in women with early breast cancer in the five years after diagnosis. Design Observational cohort study. Setting NHS breast clinic, London. Participants 222 women with early breast cancer: 170 (77%) provided complete interview data up to either five years after diagnosis or recurrence. Main outcome measures Prevalence

Caroline Burgess; Victoria Cornelius; Sharon Love; Jill Graham; Michael Richards; Amanda Ramirez

2005-01-01

72

LU Decomposition  

NSDL National Science Digital Library

Created by Stephanie Fitchett and David Smith for the Connected Curriculum Project, the purpose of this module is to examine LU decompositions of matrices and to see how an LU decomposition can improve computational efficiency in solving matrix equations. This is part of a larger collection of learning modules hosted by Duke University.

Smith, David; Fitchett, Stephanie

2010-06-07

73

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

74

Observational determinations of the proton to electron mass ratio in the early Universe  

Microsoft Academic Search

The values of the fundamental physical constants determine the nature of our universe from the height of mountains on earth to the evolution of the universe over its history. One of these constants is mu = {M_P}\\/{M_e} the ratio of the proton to electron mass. Astronomical observations provide a determination of this ratio in the early universe through observations of

Rodger I. Thompson; Jill Bechtold; John H. Black; Daniel Eisenstein; Xiaohui Fan; Robert C. Kennicutt; Carlos Martins; J. Xavier Prochaska; Yancey L. Shirley

2009-01-01

75

ROSAT PSPC Observations of Two Low Luminosity Early-Type Galaxies  

NASA Astrophysics Data System (ADS)

The x-ray spectra of early-type galaxies are composites of discrete source and diffuse hot gas components. While the emission from the most luminous galaxies is dominated by hot gas, simple scaling and binding mass arguments predict that discrete sources should become important below some transition optical luminosity. If early-type galaxies have massive halos comprising 90% of their mass and the best observational estimate of the Type Ia supernova rate, this transition luminosity should be at L_B ~ 3\\ 10(10}L_{sun ) . We present ROSAT PSPC observations of two early-type galaxies, NGC 3607 and NGC 4697, with luminosites near this transition. We discuss the spectral and spatial evidence for discrete source emission, and the resulting implications for the luminosity-scaling of the supernova rate and dark matter in early-type galaxies.

Loewenstein, Michael; Petre, Robert

1993-12-01

76

Thermal decomposition of hydrazines from reactive dynamics using the ReaxFF reactive force field.  

PubMed

We report reactive dynamics (RD) studies on: the decomposition of bulk hydrazine (N(2)H(4)); the decomposition of bulk monomethyl-hydrazine (CH(3)N(2)H(3)), hereafter referred to simply as methyl-hydrazine; the decomposition of hydrazine in the presence of hydrogen peroxide (H(2)O(2)); and decomposition hydrazine on catalytic surfaces Pt[100] and Pt[111] under various conditions. These studies use the ReaxFF reactive force field to describe the multitude of chemical reactions in these systems for a variety of reaction conditions in order to show that this approach leads to realistic decomposition mechanisms and rates. In particular, we determined how the decomposition of hydrazine is affected by temperature, pressure, and heating rate. We analyzed chemical reaction mechanism of the decomposition of hydrazine at the studied conditions and found that at lower temperatures the initial product from hydrazine decomposition is NH(3), whereas at higher temperatures H(2) and N(2) are the dominant early products. Prominent intermediates observed during these decompositions include N(2)H(3), N(2)H(2,) and NH(2), in agreement with quantum mechanical studies (7.3 ps at 3000 K). As the heating rate is decreased, the onset for hydrazine decomposition shifts to lower temperatures. Using a constant heating rate, we found that higher pressure (increased density) favors formation of NH(3) over N(2) and H(2). In studies of the catalytic decomposition of hydrazine on surfaces Pt[100] and Pt[111], we found that the presence of a Pt-catalyst reduces the initial decomposition temperature of hydrazine by about 50%. We found that the Pt[100]-surface is 20 times more active for hydrazine decomposition than the Pt[111]-surface, in qualitative agreement with experiments. These studies indicate how ReaxFF RD can be useful in understanding the chemical processes involved in bulk and catalytic decomposition and in oxidation of reactive species under various reaction conditions. PMID:19601597

Zhang, Luzheng; Duin, Adri C T van; Zybin, Sergey V; Goddard Iii, William A

2009-08-01

77

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

78

Child Observation and Accountability in Early Childhood Education: Perspectives from Australia and the United States  

Microsoft Academic Search

The changing ways child observation is being used by preschool teachers in the United States and Australia are described in relation to the accountability movement pressuring young children and their teachers in both countries. The costs of the accountability movement in early childhood education are explored, and a call for genuine accountability based on assessment strategies such as traditional child

J. Amos Hatch; Susan Grieshaber

2002-01-01

79

Early weightbearing after first metatarsophalangeal joint arthrodesis: a retrospective observational case analysis  

Microsoft Academic Search

A retrospective observational study was performed to determine if early ambulation compromised healing in patients who underwent primary first metatarsophalangeal joint arthrodesis. The records of 42 patients undergoing 47 fusions were evaluated to determine time to radiographic union, time to clinical union, and return to regular shoes. Results showed that patients achieved clinical healing at an average of 5.6 weeks,

Paul Dayton; Andrew McCall

2004-01-01

80

Child Observation and Accountability in Early Childhood Education: Perspectives from Australia and the United States.  

ERIC Educational Resources Information Center

|Describes the changing ways child observation is being used by preschool teachers in the United States and Australia in relation to the accountability movement pressuring young children and their teachers in both countries. Explores the costs of the accountability movement in early childhood education. Calls for genuine accountability based on…

Hatch, J. Amos; Grieshaber, Susan

2002-01-01

81

Early Childhood Teachers' Curriculum Beliefs: Are They Consistent With Observed Classroom Practices?  

Microsoft Academic Search

Research Findings: This study examined the consistency between early childhood teachers' self-reported curriculum beliefs and observations of their actual interactive behaviors with children in classrooms. Also tested was the hypothesized moderation by teacher and classroom characteristics of the association between beliefs and practices. A total of 58 preschool teachers completed a survey describing their professional backgrounds and curriculum beliefs. Their

Xiaoli Wen; James G. Elicker; Mary B. McMullen

2011-01-01

82

Observation of early photon conversions in high-energy cosmic-ray interactions  

SciTech Connect

High energy cosmic ray interactions were studied by the JACEE Collaboration using balloon-borne emulsion chambers at high altitude. In high energy, yet low multiplicity interactions many secondary vertices were observed, probably due to decays of short-lived particles. Early conversions of photons were found in the vicinity of these vertices. Conversion distances and angular distributions of the photons were studied.

Asakimori, K. (Kobe Women's Junior College, Kobe (Japan)); Burnett, T.H. (University of Washington, Seattle, WA (United States)); Cherry, M.L. (Louisiana State University (United States)); Christl, M.J. (G. Marshall Space Flight Center/NASA (United States)); Dake, S. (Kobe Unibersity, Kobe (Japan)); Derrickson, J.H.; Fountain, W.F. (G. Marshall Space Flight Center/NASA (United States)); Fuki, M. (Kochi University (Japan)); Gregory, J.C.; Hayashi, T. (University of Alabama, Huntsville, AL (United States)); Holynski, R. (Institute for Nuclear Physics, Krakow (Poland)); Iwai, J. (University of Washington, Seattle, WA (United States)); Iyono, A. (Okayama University of Science (Japan)); Jones, W.V. (Louisiana State University (United States)); Jurak, A. (Institute for Nuclear Physics, Krakow (Poland)); Lord, J.J. (University of Washington,Seattle WA (United States)); Miyamura, O. (Hiroshima University, Hiroshima (Japan)); Oda, H. (Kobe University, Kobe (Japan)); Ogata, T. (I; The JACEE Collaboration

1993-06-15

83

Observation of early photon conversions in high-energy cosmic-ray interactions  

NASA Astrophysics Data System (ADS)

High energy cosmic ray interactions were studied by the JACEE Collaboration using balloon-borne emulsion chambers at high altitude. In high energy, yet low multiplicity interactions many secondary vertices were observed, probably due to decays of short-lived particles. Early conversions of photons were found in the vicinity of these vertices. Conversion distances and angular distributions of the photons were studied.

Asakimori, K.; Burnett, T. H.; Cherry, M. L.; Christl, M. J.; Dake, S.; Derrickson, J. H.; Fountain, W. F.; Fuki, M.; Gregory, J. C.; Hayashi, T.; Ho?Y?ski, R.; Iwai, J.; Iyono, A.; Jones, W. V.; Jurak, A.; Lord, J. J.; Miyamura, O.; Oda, H.; Ogata, T.; Olson, E. D.; Parnell, T. A.; Roberts, F. E.; Strausz, S. C.; Takahashi, Y.; Tominaga, T.; Watts, J. W.; Wefel, J. P.; Wilczy?ska, B.; Wilczy?ski, H.; Wilkes, R. J.; Wolter, W.; Wosiek, B.; Zager, E. L.

1993-06-01

84

Spinodal decomposition, ordering transformation, and discontinuous precipitation in a Cu–15Ni–8Sn alloy  

Microsoft Academic Search

Transmission electron microscopy (TEM) was employed to study the microstructure and transformation kinetics of a Cu–15Ni–8Sn (wt%) alloy. Five different transformation products were observed: a modulated structure resulting from spinodal decomposition; a DO22 ordered structure; an L12 ordered structure; grain boundary and intragranular ? (DO3) precipitates; and discontinuous ? precipitates. It was found that spinodal decomposition occurred during the early

J.-C Zhao; M. R. Notis

1998-01-01

85

Results from UV Imaging in the HST/WFC3 Early Release Science Observations  

NASA Astrophysics Data System (ADS)

A portion of the GOOD-S field was observed with the HST Wide Field Camera 3 with both the UVIS and IR channels, as part of the Early Release Science Observations. Here we present a summary of our results from imaging intermediate redshift galaxies with an emphasis on what was learned from the ultraviolet portion of the observations. We discuss the size evolution of passively evolving galaxies, the assembly of massive spheroids during the peak epoch of the cosmic star-formation rate, the evolution and properties of UV-selected star-forming galaxies, analysis of AGN host galaxies, and the UV properties of z<1.5 early-type galaxies. Additionally, we will discuss how the UV data affect derived galaxy properties such as photometric redshifts and SED parameters. This work is based on the 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. Support for program 11359 was provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

Cohen, Seth H.; WFC3-SOC

2013-01-01

86

Spinodal decomposition in gels  

Microsoft Academic Search

We construct a Ginzburg-Landau model for gels undergoing spinodal decomposition in terms of the polymer volume fraction and a deformation tensor. We numerically demonstrate that the domain growth is extremely slowed down in late stages, where the surface tension force, which drives the coarsening in usual fluids, is cancelled by the elastic force. The patterns closely resemble those observed in

A. Onuki; S. Puri

1999-01-01

87

In situ observations of early oxide formation in steel under hot-rolling conditions.  

PubMed

A technique was developed to study in situ the early stages of the reaction between iron and air. Using a high-temperature microscope, we observed at temperatures between 1000 degrees C and 1050 degrees C and within the first 30 s of reaction, the formation of iron-oxide layers on the surface of low-carbon steel. We observed the nucleation and growth of a first layer of iron oxide and the consecutive formation in sequence, of higher iron oxides sweeping over the surface of the former oxide. The grain boundaries of the steel substrate remain visible for quite some time following exposure to an oxidizing atmosphere indicating that diffusion through steel grain boundaries may have a determining influence on the formation of oxides. These findings emphasize the importance of conducting further studies to better understand the kinetics and mechanisms by which iron-oxide layers form in the early stages of oxidation. PMID:17359249

Melfo, W M; Dippenaar, R J

2007-02-01

88

Comparisons of observed process quality in early child care and education programs in five countries  

Microsoft Academic Search

In this cross-national study, observed process quality in preschool classrooms was compared across five countries—Austria (n = 37), Germany (n=103), Portugal (n=88), Spain (n=80), and the U.S.A. (n=390). Process quality was assessed using the Early Childhood Environment Rating Scale (ECERS) and the Caregiver Interaction Scale (CIS). Both instruments had comparable properties when used in the different countries. A MANOVA found

Gottfried Wetzel

1996-01-01

89

Early integrative processes physiologically observed in dentate gyrus during an olfactory associative training in rat.  

PubMed

Modifications of synaptic efficacy in the dentate gyrus were investigated during an olfactory associative task. A group of rats was trained to discriminate between a patterned electrical stimulation of the lateral olfactory tract, used as an artificial cue, associated with a water reward, and a natural odor associated with a flash of light. Monosynaptic field potential responses evoked by single electrical stimuli to the lateral perforant path were recorded in the granular layer of the ipsilateral dentate gyrus prior to and just after each training session. An early increase in this response was observed just after the first learning session but disappeared 24 hours later. Inversely, a synaptic depression developed across sessions, becoming significant at the onset of a last (fifth) session. When a group of naive animals was pseudo-conditioned, no increase was observed and the synaptic depression was noted since the onset of the second session. In a group of rats similarly trained for only one session, and in which EPSPs were recorded throughout the 24 hours that followed, it was demonstrated that the increase lasted at least two hours, while the significant synaptic depression started after the fourth hour. These results are consistent with the early involvement of the dentate gyrus in learning the association between the cues and their respective rewards. These early integrative processes physiologically observed in dentate gyrus suggest early hippocampal processing before dentate gyrus reactivation via entorhinal cortex which will allow long-term memory storage in cortical areas once the meaning of the olfactory cues is learned. PMID:15011266

Truchet, B; Chaillan, F A; Soumireu-Mourat, B; Roman, F S

2002-06-01

90

Subionospheric early VLF signal perturbations observed in one-to-one association with sprites  

NASA Astrophysics Data System (ADS)

Observations on the night of 21 July 2003 of the ionospheric effects of a thunderstorm in central France are reported. From 0200 to 0315 UT, a camera system in the Pyrenees Mountains captured 28 sprites, triggered by +CG lightning as observed by the French METEORAGE lightning detection system. A narrowband VLF receiver located on Crete, at ˜2200 km southeast of the storm, observed subionospheric VLF signals from six ground-based transmitters. The amplitude of one of the VLF signals, originating at a transmitter located ˜150 km west of the storm and passing through the storm region, exhibited rapid onset perturbations occurring in a nearly one-to-one relationship with the optical sprites. These "early" VLF events are consistent with a process of narrow-angle forward scattering from a volume of enhanced ionization above the storm with lateral sizes larger than the VLF radio wavelength. The many +CG and -CG discharges that did not produce sprites were also found to not be associated with detectable VLF amplitude perturbations, even though some of these discharges reached relatively large peak currents. The rapid onsets of several of the sprite-related VLF perturbations were followed by relatively long onset durations, ranging from ˜0.5 to 2.5 s, indicating that these events were early but not "fast." These "early/slow" events may suggest a slow process of ionization build-up in the lower ionosphere, following intense lightning discharges that also lead to sprites. A limited number of early VLF perturbation events were also associated with whistler-induced electron precipitation events, or classic Trimpi perturbations, undoubtedly produced by the precipitation of electrons due to whistler-mode waves injected into the magnetosphere by the same lightning flash that led to the production of the sprite.

Haldoupis, C.; Neubert, T.; Inan, U. S.; Mika, A.; Allin, T. H.; Marshall, R. A.

2004-10-01

91

Intra- and inter-observer analysis in the morphological assessment of early-stage embryos  

PubMed Central

Background The aim of this study was to determine the intra- and inter-observer variability in the evaluation of embryo quality. Multilevel images of embryos on day 1, day 2 and day 3, were analysed using different morphological parameters. Methods Multilevel images of embryos on day 1, day 2 and day 3, were analysed using a standard scoring system. The kappa coefficient was calculated to measure intra- and inter-observer variability before and after training sessions. Results Good to excellent intra-observer agreement was present for most parameters exceptions being scoring the position of pronuclei and the presence of a cytoplasmic halo on day 1, multinucleation on day 2 and the size of fragments on day 3. Inter-observer agreement was only good to excellent for the number of blastomeres on day 2 and day 3 and the orientation of the cleavage axes on day 2. Training sessions had a positive impact on inter-observer agreement. Conclusion In conclusion, assessment of morphological characteristics of early stage embryos using multilevel images was marked by a high intra-observer and a moderate inter-observer agreement. Training sessions were useful to increase inter-observer agreement.

Paternot, Goedele; Devroe, Johanna; Debrock, Sophie; D'Hooghe, Thomas M; Spiessens, Carl

2009-01-01

92

[Observations of play and verbal behavior of boys with fragile X syndrome in early childhood].  

PubMed

Reports on development and behaviour in boys with fragile-X syndrome support the idea of a characteristic behavioural phenotype in this special population. Preliminary results are presented for 10 boys with fragile-X syndrome in early childhood. Severe mental handicaps and communicative abnormalities are observed less frequently than was expected on the basis of results reported for school-age children or adults. Boys with fragile-X syndrome show goal-directed and cooperative play behaviours in a Montessori play session, but less persistence and organisation than children with normal development or a mental handicap of heterogeneous origin. Results confirmed these behavioural differences as characteristic aspects of a "behavioural phenotype" in children who already in early childhood have fragile-X syndrome. PMID:10478436

Sarimski, K

1999-08-01

93

``Early/slow'' events: A new category of VLF perturbations observed in relation with sprites  

NASA Astrophysics Data System (ADS)

Analysis of subionospheric VLF transmissions, observed in relation with sprites, has led to the identification of a new category of VLF perturbations caused by the direct effects of tropospheric lightning on the overlying lower ionosphere. They constitute a large subset of the so-called "early/fast" events where now the term "fast," which implies rapid onset durations less than ˜20 ms, does not apply. In contrast with early/fast, the perturbations have a gradual growth and thus "slow" onset durations ranging from about 0.5 to 2.5 s; thus these events are labeled herein as "early/slow." They are indicative of a new physical process at work which, following a sprite-causative cloud-to-ground discharge, leads to a gradual buildup of conductivity changes in the lower ionosphere which must be responsible for the long onset durations of the observed perturbations. Analysis of broadband VLF sferic recordings, made with a two-channel receiver near the sprite producing storms, shows that the growth phase of an early/slow event coincides with the occurrence of complex and dynamic lightning action. This is composed of a few sequential cloud-to-ground lightning strokes and clusters (bursts) of sferics which are attributable to intracloud lightning. We postulate that the long onset durations are due to secondary ionization buildup in the upper D region below the nighttime VLF reflection heights, caused mainly by the impact on sprite-produced electrons of sequential electromagnetic pulses radiated upward from horizontal in-cloud discharges.

Haldoupis, C.; Steiner, R. J.; Mika, Á.; Shalimov, S.; Marshall, R. A.; Inan, U. S.; BöSinger, T.; Neubert, T.

2006-11-01

94

Early VLF perturbations observed in Crete, Greece in relation with TLEs over southwest Europe  

NASA Astrophysics Data System (ADS)

In support of the summer EuroSprite campaigns in southwest Europe, and in the framework of an EU-RTN (European Union research training network) project (e.g., http://www.dsri.dk/cal/), a Stanford narrow band VLF receiver was installed in Crete, Greece (35.31 deg. N; 25.08 deg. E) and started operation in the summer of 2003. The Crete VLF station was capable of monitoring several transmitters, some of them chosen in order to provide VLF links that traverse subionospheric regions in the proximity of the areas viewed for transient luminous event detection (sprites and elves) by the EuroSprite cameras. In this presentation we summarize several observational findings regarding the so called "early" VLF events of ionospheric perturbations which are found to occur in relation with sprites and elves. In particular, we focus on a new category of early type perturbations, which, contrary to the so called "early/fast" events whose onset duration is less than ~20 ms, are characterized by a gradual growth and thus a "slow" onset duration ranging from about 0.5 to 2.5 s. These long growths are indicative of a new physical process at work which, following a sprite-causative cloud-to-ground discharge, leads to a gradual ionization build up in the lower ionosphere which can be responsible for the long onset duration of the observed perturbations. We postulate that such long onset durations are due to secondary ionization build-up in the upper D region below the nighttime VLF reflection heights, caused mainly by the impact on sprite-produced electrons of sequential electromagnetic pulses radiated upwards from in-cloud discharges. Also, the measured early event recoveries are modeled to obtain estimates of sprite-related electron density in the upper D region.

Haldoupis, C.; Mika, A.; Inan, U.; Neubert, T.

2007-12-01

95

Perceptual contributions to problem solving: Chunk decomposition of Chinese characters.  

PubMed

Chunk decomposition is the decomposing of familiar patterns into their component elements so that they can be regrouped in another meaningful manner. Such a regrouping is sometimes critically required in problem solving because during initial encoding the problem elements become automatically grouped into familiar chunks and this may prohibit finding a novel or efficient solution to problems [G. Knoblich, S. Ohlsson, H. Haider, D. Rhenius, Constraint relaxation and chunk decomposition in insight problem solving, J. Exp. Psychol. Learn. Mem. Cogn. 25 (1999) 1534-1556]. In order to elucidate the brain mechanisms underlying the process of chunk decomposition, we developed a task that uses Chinese character as materials. Chinese characters are ideal examples of perceptual chunks. They are composed of radicals, which in turn, are composed of strokes. Because radicals are meaningful chunks themselves but strokes are not meaningful in isolation, it is much easier to separate a character by its radicals than to separate a character by its strokes. By comparing the stroke-level decomposition and the radical-level decomposition, we observed activities in occipital, frontal, and parietal lobes. Most importantly, during the moment of chunk decomposition, we found the early visual cortex showed a tendency of negative activation whereas the higher visual cortex showed a tendency of positive activation. This suggests that in order to successfully decompose a chunk, the higher visual areas must at least partly be 'disconnected' from the input provided by early visual processing in order to allow simple features to be rearranged into a different perceptual chunk. We conclude that early perceptual processes can crucially affect thinking and problem solving. PMID:17027779

Luo, Jing; Niki, Kazuhisa; Knoblich, Guenther

2006-07-28

96

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

97

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

98

Early Cruise Observations From The RAD Instrument On The Mars Science Laboratory  

NASA Astrophysics Data System (ADS)

The Radiation Assessment Detector (RAD) is a compact, lightweight energetic particle analyzer that was launched November 26, 2011 on the Mars Science Laboratory. RAD detects and analyzes energetic particle species (p, n, He, 2early results obtained by RAD during cruise, including observations from the Solar Particle Events seen in late January, 2012.

Hassler, Donald M.; Zeitlin, C.; Wimmer-Schweingruber, R.; Boettcher, S.; Martin, C.; Brinza, D.; Rafkin, S.; Posner, A.; Cucinotta, F.

2012-05-01

99

Early Cruise Observations from the RAD Instrument on the Mars Science Laboratory  

NASA Astrophysics Data System (ADS)

The Radiation Assessment Detector (RAD) is a compact, lightweight energetic particle analyzer that was launched November 26, 2011 on the Mars Science Laboratory. RAD detects and analyzes energetic particle species (p, n, He, 2early results obtained by RAD during cruise, including observations from the Solar Particle Events seen in late January, 2012.

Hassler, Donald M.; Zeitlin, Cary; Boettcher, Stephan; Wimmer-Schweingruber, Robert; Martin, Cesar; Brinza, David

2012-07-01

100

Current constraints on early dark energy and growth index using latest observations  

NASA Astrophysics Data System (ADS)

Aims: In this paper we study observational constraints on early dark energy model proposed by Doran & Robbers and growth index using the latest Union2 type Ia supernovae (SNe Ia), the baryon acoustic oscillations (BAO) in the large-scale correlation function of the Sloan Digital Sky Survey and Two-degree Field Galaxy Redshift Survey, cosmic microwave background (CMB) from the Wilkinson Microwave Anisotropy Probe seven-year data, the linear growth factors data and gamma-ray bursts (GRBs). Methods: By using the ?2 statics method, we constrain the early dark energy model and growth factor from the above datasets. When including the GRB data, we use the cosmographic parameters to calibrate the GRB luminosity relations using SNe Ia. Results: At 2? confidence level, we find that the fractional dark energy density at early times is ?de<0.05 using SNe Ia, CMB and BAO. When we include high-redshift probes, such as measurements of the linear growth factors and GRBs, the constraint is tightened considerably and becomes ?de<0.03 at 2? confidence level. We also discuss the growth rate index ?. We find ? = 0.661-0.203+0.302(1?) using the SNe Ia, CMB, BAO and linear growth factor data. After including high-redshift GRB data, the growth index is ? = 0.653-0.363+0.372.

Wang, F. Y.

2012-07-01

101

Changes in MRS neuronal markers and T cell phenotypes observed during early HIV infection  

PubMed Central

Objective: To determine if changes in brain metabolites are observed during early HIV infection and correlate these changes with immunologic alterations. Methods: Eight subjects with early HIV infection, 9 HIV-seronegative controls, and 10 chronically HIV-infected subjects without neurologic impairment underwent 1H magnetic resonance spectroscopy. Subjects with early stage infection were identified near the time of HIV seroconversion and imaged within 60 days of an evolving Western blot, while still having detectable plasma virus. Subjects had blood drawn for viral RNA and T cell quantification. Results: Both N-acetylaspartate (NAA) and Glx (glutamate + glutamine) were decreased in the frontal cortical gray matter of seropositive subjects. NAA levels were found to be decreased in the centrum semiovale white matter of chronically HIV-infected subjects, but not in those with early infection. Both HIV-infected cohorts demonstrated a lower number of CD4+ T lymphocytes and a higher number of CD8+ T lymphocytes in their blood. Lower NAA levels in the frontal cortex of subjects with early infection were associated with an expansion of CD8+ T cells, especially effector CD8+ T cells. Conclusions: These results verify metabolism changes occurring in the brain early during HIV infection. Lower NAA and Glx levels in the cortical gray matter suggests that HIV causes neuronal dysfunction soon after infection, which correlates to the expansion of CD8+ T cells, specifically to an activated phenotype. Utilizing magnetic resonance spectroscopy to track NAA levels may provide important information on brain metabolic health while allowing better understanding of the virus–host interactions involved in CNS functional deficits. GLOSSARY APC = allophycocyanin; Cho = choline; Cr = creatine; CTL = cytotoxic T lymphocyte; Cy5.5 = cyanin 5.5; FITC = fluorescein isothiocyanate; FOV = field of view; Glx = glutamate + glutamine; MI = myoinositol; MRS = magnetic resonance spectroscopy; NAA = N-acetylaspartate; NRTI = nucleoside reverse transcriptase inhibitors; PE = phycoerythrin; PerCP = peridinium chlorophyll protein; PHI = primary HIV infection; SIV = simian immunodeficiency virus; TE = echo time; TI = inversion time; TR = repetition time.

Lentz, M R.; Kim, W K.; Lee, V; Bazner, S; Halpern, E F.; Venna, N; Williams, K; Rosenberg, E S.; Gonzalez, R G.

2009-01-01

102

Observation of x-ray resonant Raman scattering: The early days  

SciTech Connect

My early observation of Raman scattering came as a serendipitous by-product of our efforts to achieve the best possible signal for x-ray fluorescent analysis. We were also investigating the x-ray spectrum produced by a monochromatic x-ray beam striking metal targets which might contribute to the inelastic background. This background could contaminate the very weak diffusively distributed elastically scattered radiation associated with defects in the perfect periodicity of crystals. Energy analysis of the x-ray spectra created by monochromatic Cu K{sub {alpha}} and Mo K{sub {alpha}} radiation impinging on highly pure metal targets showed an inelastically scattered intensity related to the energy difference between the exciting radiation and the nearest bound state. Confirmation of these observations and availability of synchrotron radiation has led to wide application of this new x-ray spectroscopy in atomic physics including its use as a probe of the unoccupied density of states.

Sparks, C.J.

1995-12-31

103

Experimental observation of critical slowing down as an early warning of population collapse  

NASA Astrophysics Data System (ADS)

Near tipping points marking population collapse or other critical transitions in complex systems small changes in conditions can result in drastic shifts in the system state. In theoretical models it is known that early warning signals can be used to predict the approach of these tipping points (bifurcations), but little is known about how these signals can be detected in practice. Here we use the budding yeast Saccharomyces cerevisiae to study these early warning signals in controlled experimental populations. We grow yeast in the sugar sucrose, where cooperative feeding dynamics causes a fold bifurcation; falling below a critical population size results in sudden collapse. We demonstrate the experimental observation of an increase in both the size and timescale of the fluctuations of population density near this fold bifurcation. Furthermore, we test the utility of theoretically predicted warning signals by observing them in two different slowly deteriorating environments. These findings suggest that these generic indicators of critical slowing down can be useful in predicting catastrophic changes in population biology.

Vorselen, Daan; Dai, Lei; Korolev, Kirill; Gore, Jeff

2012-02-01

104

Thermal decomposition of developing enamel  

Microsoft Academic Search

Summary  The decomposition of forming, maturing, and mature enamel was studied between room temperature and 1,000°C by powder X-ray\\u000a diffraction and infrared absorption methods. In mature dental enamel, carbonate decomposition proceeds relatively fast until\\u000a 500°C and at a slower rate beyond it. In forming and maturing enamel, decomposition is faster and is completed around 800°C.\\u000a The formation of ?-Ca3(PO4)2 is observed

I. Mayer; S. Schneider; M. Sydney-Zax; D. Deutsch

1990-01-01

105

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

106

Decomposition Studies of Tertiarybutyldimethylantimony.  

National Technical Information Service (NTIS)

The vapor pressure, decomposition temperature, decomposition products, and decomposition reaction order are reported for a novel organometallic vapor-phase epitaxy (OMVPE) Sb precursor, tertiarybutyldimethylantimony (TBDMSb, C4H9(CH3)2Sb). The TBDMSb vapo...

C. H. Chen C. W. Hill D. S. Cao G. B. Stringfellow S. H. Li

1992-01-01

107

VERY EARLY ULTRAVIOLET AND OPTICAL OBSERVATIONS OF THE TYPE Ia SUPERNOVA 2009ig  

SciTech Connect

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 about 1 day after explosion until around maximum brightness. Our data include excellent UV and optical light curves, 25 premaximum optical spectra, and 8 UV spectra, including the earliest UV spectrum ever obtained of an SN Ia. SN 2009ig is a relatively normal SN Ia, but does display high-velocity ejecta-the ejecta velocity measured in our earliest spectra (v Almost-Equal-To -23, 000 km s{sup -1} for Si II {lambda}6355) is the highest yet measured in an SN Ia. The spectral evolution is very dramatic at times earlier than 12 days before maximum brightness, but slows after that time. The early-time data provide a precise measurement of 17.13 {+-} 0.07 days for the SN rise time. The optical color curves and early-time spectra are significantly different from template light curves and spectra used for light-curve fitting and K-corrections, indicating that the template light curves and spectra do not properly represent all SNe Ia at very early times. In the age of wide-angle sky surveys, SNe like SN 2009ig that are nearby, bright, well positioned, and promptly discovered will still be rare. As shown with SN 2009ig, detailed studies of single events can provide significantly more information for testing systematic uncertainties related to SN Ia distance estimates and constraining progenitor and explosion models than large samples of more distant SNe.

Foley, Ryan J.; Challis, P. J.; Marion, G. H.; Kirshner, R. P. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Filippenko, A. V.; Ganeshalingam, M.; Li, W.; Silverman, J. M.; Cenko, S. B. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Landsman, W. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Beaton, R. L. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904-4325 (United States); Bennert, V. N. [Department of Physics, University of California, Santa Barbara, CA 93106-9530 (United States); Childress, M. [Physics Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Guhathakurta, P. [UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States); Jiang, L. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Kalirai, J. S. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Stockton, A. [Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States); Tollerud, E. J. [Center for Cosmology, Department of Physics and Astronomy, 4129 Frederick Reines Hall, University of California, Irvine, CA 92697 (United States); Vinko, J. [Department of Optics and Quantum Electronics, University of Szeged, Dom ter 9, Szeged H-6720 (Hungary); Wheeler, J. C., E-mail: rfoley@cfa.harvard.edu [Astronomy Department, University of Texas, Austin, TX 78712 (United States); and others

2012-01-01

108

Does Early Postresuscitation Stress Hyperglycemia Affect 72 Hour Neurologic Outcome? Preliminary Observations In The Swine Model  

PubMed Central

Background Hyperglycemia is common in the early period following resuscitation from cardiac arrest and has been shown to be a predictor of neurologic outcome in retrospective studies. The purpose of this study was to evaluate neurologic outcome and early post-arrest hyperglycemia in a swine cardiac arrest model. Methods Electrically-induced ventricular fibrillation cardiac arrest was induced in 22 anesthetized and instrumented swine. After 7 min, CPR and advanced cardiac life support was initiated. Twenty-one animals were resuscitated and serum glucose was measured at intervals for 60 min post-arrest. Animals were observed for 72 hours and neurologic score determined at 24 hr intervals. Results Ten animals demonstrated a peak plasma glucose ? 226 mg/dl during the initial 60 min post-arrest. Neurologic scores at 72 hrs in these animals (mean score = 0, mean overall performance category = 1) was the same as that in animals with a serum glucose < 226 mg/dl. End-tidal CO2 measured during CPR, time to restoration of spontaneous circulation, and epinephrine dose were not significantly different between animals with a peak glucose ? 226 mg/dl and those with lesser values. The sample size afforded a power of 90% to detect a 50 point difference from the lowest score (0 points) of the porcine neurologic outcome scale. Conclusion In this standard porcine model of witnessed out-of-hospital cardiac arrest, early stress post-resuscitation hyperglycemia did not appear to affect neurologic outcome. During the prehospital phase of treatment and transport, treatment of hyperglycemia by emergency medical service providers may not be warranted.

Niemann, James T.; Youngquist, Scott; Rosborough, John P.

2011-01-01

109

Thermal decomposition of natural dolomite  

Microsoft Academic Search

Thermal decomposition behaviour of dolomite sample has been studied by thermogravimetric (TG) measurements. Differential thermal\\u000a analysis (DTA) curve of dolomite shows two peaks at 777·8°C and 834°C. The two endothermic peaks observed in dolomite are\\u000a essentially due to decarbonation of dolomite and calcite, respectively. The TG data of the decomposition steps have also been\\u000a analysed using various differential, difference-differential and

S. Gunasekaran; G. Anbalagan

2007-01-01

110

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

111

CONSTRAINTS ON TYPE Ia SUPERNOVA PROGENITOR COMPANIONS FROM EARLY ULTRAVIOLET OBSERVATIONS WITH SWIFT  

SciTech Connect

We compare early ultraviolet (UV) observations of Type Ia supernovae (SNe Ia) with theoretical predictions for the brightness of the shock associated with the collision between SN ejecta and a companion star. Our simple method is independent of the intrinsic flux from the SN and treats the flux observed with the Swift/Ultra-Violet Optical Telescope as conservative upper limits on the shock brightness. Comparing this limit with the predicted flux for various shock models, we constrain the geometry of the SN progenitor-companion system. We find the model of a 1 M{sub Sun} red supergiant companion in Roche-lobe overflow to be excluded at a 95% confidence level for most individual SNe for all but the most unfavorable viewing angles. For the sample of 12 SNe taken together, the upper limits on the viewing angle are inconsistent with the expected distribution of viewing angles for red gaint stars as the majority of companions with high confidence. The separation distance constraints do allow main-sequence companions. A better understanding of the UV flux arising from the SN itself as well as continued UV observations of young SNe Ia will further constrain the possible progenitors of SNe Ia.

Brown, Peter J.; Dawson, Kyle S.; Harris, David W.; Olmstead, Matthew [Department of Physics and Astronomy, University of Utah, 115 South 1400 East 201, Salt Lake City, UT 84112 (United States); Milne, Peter [Steward Observatory, University of Arizona, Tucson, AZ 85719 (United States); Roming, Peter W. A. [Southwest Research Institute, Department of Space Science, San Antonio, TX 78238 (United States)

2012-04-10

112

Constraints on Type Ia Supernova Progenitor Companions from Early Ultraviolet Observations with Swift  

NASA Astrophysics Data System (ADS)

We compare early ultraviolet (UV) observations of Type Ia supernovae (SNe Ia) with theoretical predictions for the brightness of the shock associated with the collision between SN ejecta and a companion star. Our simple method is independent of the intrinsic flux from the SN and treats the flux observed with the Swift/Ultra-Violet Optical Telescope as conservative upper limits on the shock brightness. Comparing this limit with the predicted flux for various shock models, we constrain the geometry of the SN progenitor-companion system. We find the model of a 1 M? red supergiant companion in Roche-lobe overflow to be excluded at a 95% confidence level for most individual SNe for all but the most unfavorable viewing angles. For the sample of 12 SNe taken together, the upper limits on the viewing angle are inconsistent with the expected distribution of viewing angles for red gaint stars as the majority of companions with high confidence. The separation distance constraints do allow main-sequence companions. A better understanding of the UV flux arising from the SN itself as well as continued UV observations of young SNe Ia will further constrain the possible progenitors of SNe Ia.

Brown, Peter J.; Dawson, Kyle S.; Harris, David W.; Olmstead, Matthew; Milne, Peter; Roming, Peter W. A.

2012-04-01

113

Long-term climate variations on Svalbard using early instrumental observations  

NASA Astrophysics Data System (ADS)

The first permanent observation station on Spitsbergen, Svalbard was established in December 1911 by The Norwegian Meteorological Institute. Except for a period during the WW II there have been continuous observations on the island. Before the permanent station was established, i.e. in the late 19th and early 20th centuries the institute had to rely on hunting expeditions. These were equipped mainly with standard meteorological instruments of the same kind that was in current use on the mainland. However, homogenisation of the time series will be difficult as the series are short and are spread over large distances. As a part of the multidisciplinary project: Arctic Climate and Environment of the Nordic Seas and the Svalbard - Greenland Area (AWAKE) the observations are controlled and found to be of sufficient quality for use. For the homogenisation and quality check different statistical tests will be applied along with existing metadata. During the summer 2010 four stations will be re-established for measurement at the old sites (Kvalpynten, Sørkappøya, Axeløya and Sorgfjorden). This will enable a direct study of the temperature changes that have taken place since the start of each measurement series. Moreover, this will also make the basis for a study of spatial variations of the Spitsbergen climate during different seasons, taking, cloud cover, wind and ice conditions into consideration. This knowledge will be used for the construction of a composite time series for Svalbard starting in 1898, 13 years before the permanent measurements started.

Nordli, Oeyvind; Isaksen, Ketil

2010-05-01

114

Observing preschoolers' social-emotional behavior: structure, foundations, and prediction of early school success.  

PubMed

Social-emotional behavior of 352 3- and 4-year-olds attending private child-care and Head Start programs was observed using the Minnesota Preschool Affect Checklist, Revised (MPAC-R). Goals of the investigation included (a) using MPAC-R data to extract a shortened version, MPAC-R/S, comparing structure, internal consistency, test-retest reliability, and stability of both versions; and, using the shortened measure, to examine (b) age, gender, and risk status differences in social-emotional behaviors; (c) contributions of emotion knowledge and executive function to social-emotional behaviors; and (d) contributions of social-emotional behaviors to early school adjustment and kindergarten academic success. Results show that reliability of MPAC-R/S was as good, or better, than the MPAC-R. MPAC-R/S structure, at both times of observation, included emotionally negative/aggressive, emotionally regulated/prosocial, and emotionally positive/productive behaviors; MPAC-R structure was similar but less replicable over time. Age, gender, and risk differences were found. Children's emotion knowledge contributed to later emotionally regulated/prosocial behavior. Finally, preschool emotionally negative/aggressive behaviors were associated with concurrent and kindergarten school success, and there was evidence of social-emotional behavior mediating relations between emotion knowledge or executive function, and school outcomes. The importance of portable, empirically supported observation measures of social-emotional behaviors is discussed along with possible applications, teacher utilization, and implementation barriers. PMID:22919891

Denham, Susanne A; Bassett, Hideko Hamada; Thayer, Sara K; Mincic, Melissa S; Sirotkin, Yana S; Zinsser, Katherine

115

Early Solar Wind Observations from the Plasma and Suprathermal Ion Composition (PLASTIC) Experiments on STEREO  

NASA Astrophysics Data System (ADS)

Two identical Plasma and Suprathermal Ion Composition (PLASTIC) instruments are now flying on the STEREO A and B observatories, which launched in October 2006. The STEREO observatories are drifting away from the Earth and from each other, providing different longitudinal perspectives. PLASTIC together with the IMPACT suite provides the in-situ measurements for the STEREO mission, while SECCHI provides remote imaging of the solar corona. The PLASTIC solar wind sector measures solar wind proton bulk parameters and provides species identification and relative abundances for the more dominant solar wind minor (Z>2) ions. During this early part of the STEREO mission, as we approach solar minimum conditions, there have been a series of coronal- hole associated high speed streams and interstream sector boundaries. In this talk we will provide initial observations of the solar wind during selected time periods.

Galvin, A. B.; Kistler, L. A.; Popecki, M. A.; Farrugia, C.; Moebius, E.; Lee, M.; Ellis, L.; Simunac, K.; Singer, K.; Russell, C.; Walker, C.; Blush, L.; Klecker, B.; Wimmer-Schweingruber, R. F.; Thompson, B.; Bochsler, P.; Wurz, P.; Daoudi, H.; Giammanco, C.; Karrer, R.; Opitz, A.; Koeten, M.; Luhmann, J.; Howard, R.; Wuelser, J. P.; Acuna, M.

2007-05-01

116

Bernardino Ramazzini's early observations of the link between musculoskeletal disorders and ergonomic factors.  

PubMed

Bernardino Ramazzini (1633-1714) systematically studied the relationship between work and diseases. He realized that it was not possible to ascribe all workers' diseases to chemicals or physical agents and foresaw that other factors were involved. He observed that common diseases could originate following the maintenance either of prolonged stationary postures or of unnatural postures (e.g. bakers, workers who stand, sedentary worker, scribes, weavers) or following activities requiring heavy muscular performance (e.g. porters and woodworkers). Furthermore, Ramazzini recognized the need to undertake measures to prevent disorders from repetitive motions and manual lifting and anticipated the now accepted advice of moderation and recommendations of reduction of work duration for a number of hard jobs requiring a standing position or severe muscular effort. From his early writings therefore it is evident that Ramazzini realized the importance of assessing the ergonomic factors associated with the occurrence of work-related musculoskeletal disorders. PMID:14985142

Franco, Giuliano; Fusetti, Leonardo

2004-01-01

117

Microbial activities during the early stage of laboratory decomposition of tropical leaf litters: the effect of interactions between litter quality and exogenous inorganic nitrogen  

Microsoft Academic Search

The comparative decomposition of tropical leaf litters (e.g. Andropogon gayanus, Casuarina equisetifolia, Faidherbia albida) of different qualities was investigated under laboratory conditions during a 60-day incubation period conducted with a typical oxisol. Total CO 2-C, soil inorganic N, microbial biomass (fumigation-extraction), ß-glucosidase and dehydrogenase activities were determined over the incubation to assess how they responded to the addition of inorganic

SaïdouNourou Sall; Dominique Masse; France Bernhard-Reversat; Aliou Guisse; Jean-Luc Chotte

2003-01-01

118

SN IA Enrichment in Virgo Early-type Galaxies from ROSAT and ASCA Observations  

NASA Astrophysics Data System (ADS)

We analyzed nine X-ray-bright Virgo early-type galaxies observed by both ASCA and ROSAT. Through spatially resolved spectroscopy, we determined the radial temperature profiles and abundances of Mg, Si, and Fe for six galaxies. The temperature profiles are consistent with isothermal temperatures outside of cooler regions at the galaxies' centers. We present new evidence for iron abundance gradients in NGC 4472 and NGC 4649 and confirm the previous results on NGC 4636. Mg and Si abundance gradients on average are flatter than those of iron and correspond to an underabundance of ?-process elements at high Fe values, while at low iron the element ratios favor enrichment by Type II supernovae (SNe). We explain the observed trend using the metallicity dependence of SN Ia metal production and present constraints on the available theoretical modeling for low-metallicity inhibition of SNe Ia. Our results imply a cutoff metallicity in the range 0.07-0.3 solar and require a lower limit of 0.3 solar on the Fe contribution of SN Ia. We estimate an SN Ia rate at the centers of the brightest galaxies in our sample of ~0.08 h375 SNU (supernova units). The rates inferred from optical searches should be corrected for the presence of ``faint'' SN Ia events, since these release limited metals and therefore do not contribute significantly to the measured metallicity in the X-ray gas. With this correction the present-epoch SN Ia rate in early-type galaxies is 0.10+/-0.06 h275 SNU and is therefore comparable with the X-ray estimates. A simple comparison shows that the X-ray abundances we derive are still discrepant from optically determined values. We attribute this difference to the low spatial resolution of our X-ray measurements, radial gradients in the abundances, and the importance of hydrodynamical effects, particularly the inflow of cooling gas, on the measured X-ray abundances.

Finoguenov, A.; Jones, C.

2000-08-01

119

In situ observations of soil minerals and organic matter in the early phases of prescribed fires  

NASA Astrophysics Data System (ADS)

We examined the chemical composition of aerosol samples collected during a prescribed fire at a Great Basin Desert site in the context of samples collected from controlled combustion of vegetation clippings from the same site and resuspension of soil samples obtained prior to and after the burn event. We observed a distinct difference in the composition of organic carbon resuspended soil dust after the burn, reflecting changes caused by the heating of the soil. The relative abundances of minerals and organic carbon fractions in aerosols collected during the first period of the burn were identical to those measured in soil dust. For aerosol samples collected for the remaining two periods of the burn event, the profiles of both minerals and organic carbon matched quite well those observed for vegetation combustion. Reconstruction of aerosol samples collected during the burn event showed that vegetation combustion dominated emissions but mineral soil dust may account for about 10% of PM10emissions (reconstructed) during the early stages of the fire. A large fraction of emissions during the first two hours was also unaccounted mainly because of the insufficient conversion of organic carbon to organic mass. The abundance of heavier non-volatile organics in soil dust suggested the presence of humic/fulvic acids that exhibit higher OM-to-OC ratios and thus, account for a proportion of the unaccounted emissions. These findings indicated that soil dust may be released into the air during a fire event, probably due to the enhanced turbulent mixing near the burn front.

Kavouras, Ilias G.; Nikolich, George; Etyemezian, Vic; Dubois, David W.; King, James; Shafer, David

2012-06-01

120

Lightning Sensing from Space: Early Observations to the Geostationary Lightning Mapper (Invited)  

NASA Astrophysics Data System (ADS)

Lightning was serendipitously detected by some of the earliest space-based sensors. Small instruments of opportunity such as the Piggy Back Experiment followed these early observations. In 1980, NASA began a serious study on the possibility for observing lightning from geostationary orbit. An U-2 aircraft was instrumented with optical and electric field sensors and flown over the tops of thunderstorms. This early work quantified the characteristics of the lightning optical emissions radiating from cloud tops and lead to the selection of the 774 nm oxygen emission line (originally identified by Leon Salanave) as the line of choice for space-based lightning observations. The U-2 results provided the basis for the Optical Transient Detector (OTD) and the Lightning Imaging Sensor (LIS) designs. The OTD and LIS were the first pixilated lightning sensors to be flown in space, an approach that enabled high detection efficiency for both cloud and ground flashes and good spatial resolution. OTD and LIS data provided the first detailed view of the global distribution of lightning activity, an accurate estimate of the global flash rate, helped quantify the global relationship between ice flux and flash rates, provided a lightning climatology over a continuous 15 year interval and made numerous other contributions. In addition, OTD and LIS data provided the detailed characterization of optical lightning emissions that been necessary for the effective design of geostationary-based lightning sensors. The low earth orbiting lightning data played an essential role in refining the conceptional design of the Lightning Mapper Sensor (LMS) and provided the basis for the detailed design of the Geostationary Lightning Mapper (GLM) which is scheduled to be launch on the GOES-R satellite. The GLM is being designed to detect 90% of all lightning flashes within its field of view with less than a 5% false alarm rate and a spatial resolution of 8 km. An analysis of how these performance goals can be achieved will be presented along with details of how lightning characteristics drove the instrument design.

Christian, H.

2010-12-01

121

Early and Efficient Detection of Mycobacterium tuberculosis in Sputum by Microscopic Observation of Broth Cultures  

PubMed Central

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.

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

122

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

2013-02-28

123

The initial changes of fat deposits during the decomposition of human and pig remains.  

PubMed

The early stages of adipocere formation in both pig and human adipose tissue in aqueous environments have been investigated. The aims were to determine the short-term changes occurring to fat deposits during decomposition and to ascertain the suitability of pigs as models for human decomposition. Subcutaneous adipose tissue from both species after immersion in distilled water for up to six months was compared using Fourier transform infrared spectroscopy, gas chromatography-mass spectrometry and inductively coupled plasma-mass spectrometry. Changes associated with decomposition were observed, but no adipocere was formed during the initial month of decomposition for either tissue type. Early-stage adipocere formation in pig samples during later months was detected. The variable time courses for adipose tissue decomposition were attributed to differences in the distribution of total fatty acids between species. Variations in the amount of sodium, potassium, calcium, and magnesium were also detected between species. The study shows that differences in total fatty acid composition between species need to be considered when interpreting results from experimental decomposition studies using pigs as human body analogs. PMID:19018935

Notter, Stephanie J; Stuart, Barbara H; Rowe, Rebecca; Langlois, Neil

2008-11-10

124

Matrix and Tensor Decompositions  

NASA Astrophysics Data System (ADS)

Advances in high-throughput technologies such as gene and protein expression microarrays in the past decade have made it possible to simultaneously measure the expression levels of thousands of transcripts. This has resulted in large amounts of biological data requiring analysis and interpretation. Many methods for handling such large-scale data have been proposed in the literature. For example, consider a p ×n gene expression matrix V consisting of observations on p genes from n samples representing different experimental conditions, phenotypes or time points. One could be interested in identifying clusters of genes with similar expression profiles across sub-groups of samples. Typically, this is accomplished via a decomposition of V into two or more matrices where each factored matrix has a distinct physical interpretation. Matrix decompositions have been successfully utilized in a variety of applications in computational biology such as molecular pattern discovery, class comparison, class prediction, functional characterization of genes, cross-platform and cross-species analysis, and biomedical informatics. In this chapter, we focus on available and commonly utilized methods for such matrix decompositions as well as survey other potentially useful methods for analyzing highdimensional data.

Devarajan, Karthik

125

Decomposition of perfluoropolyether lubricants  

Microsoft Academic Search

Decomposition has been studied in the chemistry of perfluoropolyethers (PFPE), thus far no molecular structure information\\u000a is reported. TG-MS is a tool to follow the off gassing of decomposition for clues. We selected two PFPEs that have different\\u000a properties: Krytox® XHT-1000 and Fomblin Z60 heating to normal decomposition and catalytic decomposition in the presence of\\u000a alumina powder. Comparing the decomposition

Mimi Y. KeatingJon; Jon L. Howell

126

Diastolic dysfunction and mortality in early severe sepsis and septic shock: a prospective, observational echocardiography study  

PubMed Central

Background Patients with severe sepsis or septic shock often exhibit significant cardiovascular dysfunction. We sought to determine whether severity of diastolic dysfunction assessed by transthoracic echocardiography (TTE) predicts 28-day mortality. Methods In this prospective, observational study conducted in two intensive care units at a tertiary care hospital, 78 patients (age 53.2?±?17.1?years; 51% females; mean APACHE II score 23.3?±?7.4) with severe sepsis or septic shock underwent TTE within 6?h of ICU admission, after 18 to 32?h, and after resolution of shock. Left ventricular (LV) diastolic dysfunction was defined according to modified American Society of Echocardiography 2009 guidelines using E, A, and e’ velocities; E/A and E/e’; and E deceleration time. Systolic dysfunction was defined as an ejection fraction?observed among patients with grade I diastolic dysfunction, an effect that persisted after controlling for age and APACHE II score. At time of initial TTE, central venous pressure (CVP) (11+/- 5?mmHg) did not differ among grades I-III, although patients with grade I received less intravenous fluid. Conclusions LV diastolic dysfunction is common in septic patients. Grade I diastolic dysfunction, but not grades II and III, was associated with increased mortality. This finding may reflect inadequate fluid resuscitation in early sepsis despite an elevated CVP, suggesting a possible role for TTE in sepsis resuscitation.

2012-01-01

127

Observations of auroral roar emissions at polar cap latitudes: Results from the Early Polar Cap Observatory  

NASA Astrophysics Data System (ADS)

Auroral roar, a radio emission occurring near the second and third electron cyclotron harmonics, has been monitored during a 51-day interval in 1998 from three ground-based high-latitude observatories: Churchill (69° corrected geomagnetic latitude (cgm)), Baker Lake (74° cgm), and the Early Polar Cap Observatory (EPCO) at Resolute (84° cgm). These observations reveal a latitude dependence of the local time distribution of auroral roar events. In the auroral zone they occur predominantly in the premidnight-midnight sector as previously reported, but in the polar cap they occur evenly throughout nighttime hours. Sorting the data by magnetic activity level confirms the effect; for example, the distribution of events at Baker Lake during times of extremely low activity (Kp<1) is concentrated near magnetic midnight, consistent with Baker Lake lying in the auroral zone when the oval is contracted. The latitude dependence of the local time distribution may be explained by propagation effects, with inefficient propagation in the auroral zone causing only relatively locally generated emissions to be detected there, while stations well poleward of the auroral zone detect emissions from sources widely distributed in longitude and latitude. Statistics of the frequencies of auroral roar events detected at Resolute show evidence of an upper frequency cutoff near 2960 kHz. Ray-tracing calculations suggest that it is plausible for auroral roar to reach Resolute from sources up to 1500 km distant in the auroral zone, but they do not provide an obvious explanation for the frequency cutoff.

LaBelle, J.; Hughes, J. M.

128

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

129

Direct GRB fireball Lorentz factor measurements through REM early afterglow observations  

NASA Astrophysics Data System (ADS)

The huge energies involved in gamma-ray bursts (GRBs) coupled with the short emission time scales unavoidably imply that the emitting source is moving relativistically, with a speed close to that of light. Here we present the REM telescope observations of the early-time near-infrared light curves of the GRB 060418 and GRB 060607A afterglows. The detection of the afterglow peak provides for the first time a direct measurement of the initial Lorentz factor ?0 of the radiating material. We find that the emitting region was indeed highly relativistic in the first seconds after the explosions, with ?0˜400. Comparison with the Lorentz factor as determined at later epochs provides direct evidence that the emitting shell is decelerating and confirms that the afterglow emission is powered by the dissipation of bulk kinetic energy. The deceleration radius was inferred to be R dec?1017 cm. This is much larger than the internal shocks radius (believed to power the prompt emission), thus providing further evidence for a different origin of the prompt and afterglow stages of the GRB.

Vergani, Susanna D.

2007-10-01

130

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

131

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

132

Effects of topical bevacizumab application on early bleb failure after trabeculectomy: observational case series  

PubMed Central

Background The aim of this study was to evaluate the influence of topical bevacizumab on the formation and function of filtering blebs in eyes with early bleb failure after antiglaucoma surgery. Methods Of all patients who underwent mitomycin-augmented trabeculectomy for glaucoma in the Department of Ophthalmology at the Medical University in Lublin, Poland, between March 2009 and March 2010, a total of 21 eyes from 20 patients with injected filtration bleb 9.8 ± 4.7 days after surgery were included in this observational case series. All patients were treated with standard steroid therapy and topical bevacizumab 5 mg/mL five times a day for 20.9 ± 9.8 days. Patients were followed up every other day, and a full eye examination was performed 14, 30, 60, and 180 days after initiation of treatment. Blebs were evaluated for vascularity by slit-lamp examination with concomitant photographic documentation and intraocular pressure measurement. Results Elevated functional bleb with significantly reduced vascularity was present in 16 eyes, and was flat and nonfunctional in five eyes. Intraocular pressure in all eyes decreased from a mean of 26.6 ± 9.6 mmHg before surgery to 14.6 ± 7.7 mmHg and 15.8 ± 8.3 mmHg at 2 and 6 months after surgery, respectively. Filtration bleb leak was noted in three eyes while on treatment with bevacizumab. Conclusion Topical application of bevacizumab might favor functional bleb formation after trabeculectomy in eyes with a high risk of failure.

Klos-Rola, Justyna; Tulidowicz-Bielak, Maria; Zarnowski, Tomasz

2013-01-01

133

Observations of intergalactic heavy-element enrichment in the early universe  

NASA Astrophysics Data System (ADS)

We present the results of a search for O VI absorption in the intergalactic medium (IGM) at 2 [Special characters omitted.] z [Special characters omitted.] 3. The measurements are taken from a set of 7 quasars observed with Keck I/ HIRES. We find two classes of O VI system in the high redshift IGM. The first class is more rare (2-4 per sightline) and also quite strong ( N H I >= 10 15.2 ). These systems resemble hot, collisionally ionized gas at high densities, and contain complex mixtures of H I and metals at a range of temperatures. Although we cannot measure the metallicities of individual strong absorbers, we estimate that the total population is enriched over 10 times above the level of the general IGM. We propose that the strong systems represent either accretion-shocked gas falling onto primitive large-scale structure, or (more likely) the remnants of high redshift galactic winds mixing into the IGM. The second class of O VI absorber is much weaker, arising in low-density gas that is photoionized by metagalactic UV/X-ray radiation. We measure the metal content of these systems, down to densities of r/ r [Special characters omitted.] 1.6 relative to the cosmic mean. This corresponds to the filaments of the cosmic web, which contain over half of the baryons in the high redshift universe. We develop a new method to calculate the metallicity distribution function of the Ly-a forest using survival statistics. Carbon and oxygen are both distributed lognormally, with mean [left angle bracket][ O/H ][right angle bracket] [approximate] -2.85 and scatter of s = 0.75 dex. We observe no decline in metallicity toward lower densities, indicating that metals are mixed very efficiently within the filaments. Comparison with Population III and galactic wind enrichment models suggests that the enrichment was dominated by superwinds. We estimate that roughly half of all baryons in the IGM came into contact with metal-rich winds by z ~ 2.5. Using a "closed box" model of intergalactic enrichment, we estimate that early galaxies typically recycled 0.1-0.4% of their mass back into the IGM as heavy elements prior to this epoch.

Simcoe, Robert Andrew

2004-12-01

134

Observations of the soft gamma-ray early afterglow emission from two bright gamma-ray bursts  

Microsoft Academic Search

We present the results of observations of the soft gamma-ray early afterglows with the energy above 100 keV from two bright Gamma-ray bursts detected by the PHEBUS instrument of the GRANAT orbital observatory. We show that the light curves of GRB 910402 and GRB 920723 events present the afterglow emission with fading fluxes. During our observations (~700 s) for these

A. Yu. Tkachenko; O. V. Terekhov; R. A. Sunyaev; R. A. Burenin; C. Barat; J.-P. Dezalay; G. Vedrenne

2000-01-01

135

Observation of super-Poisson statistics of bacterial (Photobacterium phosphoreum) bioluminescence during the early stage of cell proliferation  

Microsoft Academic Search

We studied the process of the analysis of photon statistics for extraction of physiological information from chemiluminescence accompanying biological phenomena implicated in metabolic processes. A super-Poisson behavior in the early stages of cell proliferation of marine luminescent bacteria was observed by characterization of Fano factor of detected photoelectron time series. It is suspected that there is clustering of photon emission

Masaki Kobayashi; B. Devaraj; Humio Inaba

1998-01-01

136

Early warning for volcanic activity investigated from the 2008 Chaiten eruption based on long-term observation by microwave radiometer  

Microsoft Academic Search

A microwave radiometer can observe thermal emission from the ground with less contamination by clouds than an infrared radiometer. However, because its spatial resolution is large, if an analysis method to compensate the disadvantage is developed, it should be more suitable to issue an alert for a volcanic activity in the early stage before an eruption. We have investigated an

Takashi Maeda; Tadashi Takano

2011-01-01

137

Decomposition studies of tertiarybutyldimethylantimony  

Microsoft Academic Search

The vapor pressure, decomposition temperature, decomposition products, and decomposition reaction order are reported for a\\u000a novel organometallic vapor-phase epitaxy (OMVPE) Sb precursor, tertiarybutyldimethylantimony (TBDMSb, C4H9(CH3)2Sb). The TBDMSb vapor pressure is 7.3 Torr at 23 C. The 50% decomposition temperature is 300 C for both He andD\\u000a 2 ambients in a flow tube reactor with a residence time of approximately 3.2

D. S. Cao; C. H. Chen; C. W. Hill; S. H. Li; G. B. Stringfellow; D. C. Gordon; D. W. Brown; B. A. Vaartstra

1992-01-01

138

Modeling macrophyte decompositions in Lake Baiyangdian, China  

NASA Astrophysics Data System (ADS)

Detritus decomposition is a critical process in eutrophic shallow lakes, since it can influence accumulation of the sediment layer at lake bottoms and regulate lake terrestrialization in the long run. However, characteristics of macrophyte decomposition in nutrient enriched aquatic ecosystems have not yet been well explored. In order to better understand how plant detritus decomposition would respond to nutrient increase in eutrophic shallow lakes, a process based ecosystem model has built to simulate major macrophyte decompositions in Lake Baiyangdian based on our field works. The model is composed of four components, including hydrology, plant physiology, water chemistry, and sediment biochemistry. In the model, the sediment biochemistry considers nutrient and carbon dynamics as well as detritus accumulation from macrophytes decomposition. Effects of both abiotic factors and biotic factors controlling detritus decomposition were simulated and tested. Calibration and validation of the model were performed using observed data in the lake. Multi-variate sensitivity analysis was used to identify the dominant factors controlling decompositions. Results of this study demonstrate that the model is able to reconstruct decomposition process in the lake. The detritus decomposition processes are sensitive to the phosphorus (P) and nitrogen (N) contents in detritus. Furthermore, the model was employed to predict the long-term effects of water nutrients increase. Enriched water nutrients will greatly enhance plant growth and alter detritus accumulation at the lake bottom. This study may provide some insights for management practices aiming to protect the functioning and structure of the lake ecosystem.

Li, X.; Cui, B.; Tian, H.; Yang, Q.; Chen, G.

2011-12-01

139

Spinodal decomposition, ordering transformation, and discontinuous precipitation in a Cu-15Ni-8Sn alloy  

SciTech Connect

Transmission electron microscopy (TEM) was employed to study the microstructure and transformation kinetics of a Cu-15Ni-8Sn (wt %) alloy. Five different transformation products were observed: a modulated structure resulting from spinodal decomposition; a DO{sub 22} ordered structure; and L1{sub 2} ordered structure; grain boundary and intragranular {gamma} (DO{sub 3}) precipitates; and discontinuous {gamma} precipitates. It was found that spinodal decomposition occurred during the early stage of decomposition below {approximately}500 C. DO{sub 22} ordering appeared after spinodal decomposition, and L1{sub 2} ordering appeared after DO{sub 22} ordering. Discontinuous precipitation took place at a very late stage of the decomposition process. A time-temperature transformation (TTT) diagram was established on the basis of extensive TEM characterization. Five separate C-curves were found for the five transformation products. This TTT diagram is very helpful in clarifying the confusion and inconsistency in the literature concerning the precipitation process in the alloy. This work is one of the first experimental studies which report that spinodal decomposition can take place before ordering. It also provides evidence for the coexistence of both DO{sub 22} and L1{sub 2} long range order (LRO) structures in the alloy.

Zhao, J.C.; Notis, M.R. [Lehigh Univ., Bethlehem, PA (United States). Dept. of Materials Science and Engineering

1998-07-24

140

What's Appropriate about Developmentally Appropriate Practices? Observing Early Childhood Development Center Classroom Environments.  

ERIC Educational Resources Information Center

|This chapter is part of a book that recounts the year's work at the Early Childhood Development Center (ECDC) at Texas A & M University-Corpus Christi. Rather than an "elitist" laboratory school for the children of university faculty, the dual-language ECDC is a collaboration between the Corpus Christi Independent School District and the…

Ricard, Richard J.; Brown, Angela; Sanders, Jana

141

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

142

From Home to the Home Corner: Observing Children's Identity-Maintenance in Early Childhood Settings  

ERIC Educational Resources Information Center

|This article draws on data from two recent studies of young children in early childhood settings. One study was of children in a Korean private kindergarten, the other of children in a UK reception class. In each study, the data discussed include both evidence from "home" (including parent interviews) and evidence from "school" (including…

Brooker, Liz

2006-01-01

143

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

144

Results of observation of the geomechanical conditions of a rock bed during the early sagging of the bed roof  

SciTech Connect

The authors have analyzed the observations of rock pressure effects in mechanized Kuzbass mines. They identify two groups of mine beds differing by the varying pattern of the geomechanical state of the bed during the development and manifestation of early roof sagging. In 47% of Kuzbass seams, rock pressure producing the roof sagging presents a high risk to the safety of breakage stopes. Expressions have been derived for predicting the size of the potential zone affected by the early roof sagging in Suzbass mines.

Neborskii, V.M.

1986-05-01

145

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

PubMed

This short-term longitudinal study (N = 112) was conducted to explore the concurrent and prospective associations between teacher-reported impulsive-hyperactive behavior and observed relational and physical aggression during early childhood (M = 45.54 months old, SD = 9.07). Multiple informants and methods including observational methods (i.e., 160 min per child) were used to assess aggression and impulsivity-hyperactivity. All measures were found to be valid and reliable. Prospective hierarchical regression analyses revealed that impulsivity-hyperactivity was associated with increases in observed physical aggression across time, controlling for initial relational aggression and gender. These findings add to the growing developmental psychopathology literature that suggests that distinguishing between subtypes of aggression during early childhood may be important for understanding the course of impulsivity-hyperactivity in young children. Implications for practice are discussed. PMID:19296045

Ostrov, Jamie M; Godleski, Stephanie A

2009-03-19

146

Welander's distal myopathy: clinical, neurophysiological and muscle biopsy observations in young and middle aged adults with early symptoms.  

PubMed Central

Nine young or middle aged patients with early symptoms of Welander's distal myopathy were subjected to a detailed neurological examination including quantitative sensory testing, determination of motor and sensory nerve conduction velocity (NCV), sensory nerve action potentials, electromyography (EMG) and muscle biopsy from the tibialis anterior muscle (TA). Slight weakness of the extensors of the fingers and hands was found in all nine patients, and of the dorsiflexors of the feet in seven. All patients had a distal sensory disturbance most prominent for temperature which agrees with earlier observations. EMG changes in TA and extensor digitorum communis (EDC) muscles were of myopathic type. Slight abnormalities compatible with either myopathy or early neuropathy were found in one muscle biopsy. These findings indicate that a neurogenic lesion affecting at least the peripheral sensory system is present at an early stage of Welander's distal myopathy and that the neurogenic lesion might precede the myopathic changes. Images

Borg, K; Ahlberg, G; Borg, J; Edstrom, L

1991-01-01

147

Hubble Space Telescope WFC3 Early Release Science: Emission-line Galaxies from Infrared Grism Observations  

Microsoft Academic Search

We present grism spectra of emission-line galaxies (ELGs) from 0.6 to 1.6 mum 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 mum grism data in GOODS-South from the PEARS program, extending the wavelength coverage well past the G800L red cutoff. The Early

Amber N. Straughn; Harald Kuntschner; Martin Kümmel; Jeremy R. Walsh; Seth H. Cohen; Jonathan P. Gardner; Rogier A. Windhorst; Robert W. O'Connell; Norbert Pirzkal; Gerhardt Meurer; Patrick J. McCarthy; Nimish P. Hathi; Sangeeta Malhotra; James Rhoads; Bruce Balick; Howard E. Bond; Daniela Calzetti; Michael J. Disney; Michael A. Dopita; Jay A. Frogel; Donald N. B. Hall; Jon A. Holtzman; Randy A. Kimble; Max Mutchler; Francesco Paresce; Abhijit Saha; Joseph I. Silk; John T. Trauger; Alistair R. Walker; Bradley C. Whitmore; Erick T. Young; Chun Xu

2011-01-01

148

Kinetics of spinodal decomposition in a critical polymer solution  

SciTech Connect

This paper reports that spinodal decomposition in a critical mixture of polydimethylsiloxane and diethyl carbonate was investigated by a time-resolved light-scattering technique in the time region of the early to the intermediate stage of phase separation. The exponential growth of the scattered light intensity without changing the wave number of its peak was observed, in good agreement with the linearized theory of Cahn-Hillard. The quench depth dependences of the interdiffusion coefficient and of the wave number corresponding to the most dominant fluctuation show the three-dimensional Ising-model behavior indicating the validity of the symmetric law of critical-point universality.

Kubota, K.; Kuwahara, N. (Dept. of Biological and Chemical Engineering, Faculty of Technology, Gunma Univ., Kirya, Gunma 376 (Japan))

1992-08-10

149

Computer simulation of spinodal decomposition in ternary systems  

Microsoft Academic Search

The non-linear spinodal decomposition kinetics of a quenched homogeneous ternary alloy within three- or two-phase fields is modeled using a computer simulation technique formulated in the reciprocal lattice. Based on two-dimensional computer simulations, it is shown that, similar to binary alloys, spinodal decomposition in a ternary system usually produces interconnected morphologies at the very early stages of decomposition. For most

L CHEN

1994-01-01

150

Observation of super-Poisson statistics of bacterial (Photobacterium phosphoreum) bioluminescence during the early stage of cell proliferation  

NASA Astrophysics Data System (ADS)

We studied the process of the analysis of photon statistics for extraction of physiological information from chemiluminescence accompanying biological phenomena implicated in metabolic processes. A super-Poisson behavior in the early stages of cell proliferation of marine luminescent bacteria was observed by characterization of Fano factor of detected photoelectron time series. It is suspected that there is clustering of photon emission at the elementary luminescence process generated by the activation of luminescent enzymes.

Kobayashi, Masaki; Devaraj, B.; Inaba, Humio

1998-02-01

151

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

152

An Observational Analysis of Behavior in Depressed Preschoolers: Further Validation of Early-Onset Depression  

ERIC Educational Resources Information Center

|Objective: To investigate whether higher levels of negative and lower levels of positive behaviors could be observed in a sample of depressed preschoolers. Support for the validity of preschool depression is now available; however, objective evidence of negative behaviors among depressed preschoolers is needed. Method: A structured observational

Luby, Joan L.; Sullivan, Jill; Belden, Andy; Stalets, Melissa; Blankenship, Samantha; Spitznagel, Edward

2006-01-01

153

Reactive molecular dynamics simulation of solid nitromethane impact on (010) surfaces induced and nonimpact thermal decomposition.  

PubMed

Which is the first step in the decomposition process of nitromethane is a controversial issue, proton dissociation or C-N bond scission. We applied reactive force field (ReaxFF) molecular dynamics to probe the initial decomposition mechanisms of nitromethane. By comparing the impact on (010) surfaces and without impact (only heating) for nitromethane simulations, we found that proton dissociation is the first step of the pyrolysis of nitromethane, and the C-N bond decomposes in the same time scale as in impact simulations, but in the nonimpact simulation, C-N bond dissociation takes place at a later time. At the end of these simulations, a large number of clusters are formed. By analyzing the trajectories, we discussed the role of the hydrogen bond in the initial process of nitromethane decompositions, the intermediates observed in the early time of the simulations, and the formation of clusters that consisted of C-N-C-N chain/ring structures. PMID:22404203

Guo, Feng; Cheng, Xin-lu; Zhang, Hong

2012-03-29

154

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

155

Early-infantile galactosialidosis: Clinical, biochemical, and molecular observations in a new patient  

SciTech Connect

Few patients with the early-infantile form of galactosialidosis have been described to date. Presented here is the first Italian case. Fetal hydrops was detected by ultrasound at week 24 of gestation. At birth, the infant presented with hypotonial, massive edema, a flattened coarse facies. telangiectasias, and hepatosplenomegaly, but no dysostosis multiplex. The patient died 72 days postpartum. Excessive sialyloligosaccharides in urine, as well as vacuolation of lymphocytes and eosinophilic granulocytes in peripheral blood, were indicative of a lysosomal storage disease. In the patient`s fibroblasts, both {alpha}-neuraminidase and {beta}-galactosidase activities were severely reduced, and cathepsin A activity was <1% of control levels, confirming the biochemical diagnosis of galactosialidosis. However, in contrast to previously reported early-infantile cases, a normal amount of protective protein/cathepsin A mRNA was detected on Northern blots. This mutant transcript was translated into a precursor protein that was not processed into the mature enzyme and lacked both protective and catalytic activities. 28 refs., 4 figs., 1 tab.

Zammarchi, E.; Donati, M.A.; Morrone, A. [Univ. of Florence (Italy)] [and others

1996-08-23

156

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

157

[Indicators of early Alzheimer dementia in family practice. Development and validation of the Observation List of Early Symptoms of Dementia (OLD)].  

PubMed

Aim of the study was the development and validation of a short observation list of possible early signs of dementia (OLD) for use in general practice. A stepwise development was carried out using reviews of publications and expert consensus. Experimental observations were carried out by 22 general practitioners in 19 Dutch practices. A field study (with interviews and family forms) was conducted out afterwards, to evaluate reliability and validity. Data reduction techniques were used to construct a short version. The first two patients seen on 15 working days (N = 470) were observed. Inclusion criteria: age > 75, without a known diagnosis of dementia. Exclusion: psychiatric treatment, severe depression, acute illness with confusion. The patients were divided into three groups with no, intermediate, and the most signs (total of interviewed patients n = 60; family forms n = 39). Cronbach's alpha and factor-analysis were used to evaluate the reliability. The Cognitive Screening Test (CST), the Word Learning Test (WLT; total and retention), the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE), the Groningen Activities Restriction Scale (GARS), and an IADL scale were used to evaluate convergent validity. The Geriatric Depression Scale (GDS) was used to evaluate discriminant validity. Construct validity was evaluated using PRINCALS. Incremental validity was evaluated using the intuitive opinion of the GP (McNemar test). The reliability in the total group was 0.88, the first factor explained 42.5% of the variance. Convergent validity (2-side ANOVA) results: CST (p = 0.00), WLT-total (p = 0.001), WLT retention (p = 0.00), IQCODE (p = 0.09). No statistically significant differences were found for GARS and IADL. The GDS (p = 0.30) showed no difference. The first factor of PRINCALS explained 48% of the variance. The OLD added to the GP opinion (McNemar p = 0.00). Reliability of the short version (12 items) was 0.89 (interviewed group), and 0.86 (total group). The conclusion is that the OLD is a valid and reliable method to detect early signs of dementia in general practice. (Partly adapted from: Hopman-Rock M, Tak ECPM, Staats PGM. Development and validation of the Observation List for early signs of Dementia (OLD). Int J Geriatr Psychiatry 2001 (in press)). PMID:11370580

Hopman-Rock, M; Tak, E C; Staats, P G; Jonker, C; Wind, A W

2001-04-01

158

Exploring Early Tharsis: Gravity Observations of Radiating Dike Swarms in the Thaumasia Region of Mars  

NASA Astrophysics Data System (ADS)

Gravity observations in Thaumasia indicate the presence of several high density subsurface structures radiating away from Tharsis. The most likely interpretation is that these are dike systems associated with the Claritas Fossae graben system and in Solis Planum.

Kiefer, W. S.

2008-03-01

159

CaII K interstellar observations towards early-type disc and halo stars  

Microsoft Academic Search

We present high-resolution (R=lambda\\/Deltalambda~ 40000) CaII K interstellar observations (lambdaair= 3933.66Å) towards 88 mainly B-type stars, of which 74 are taken from the Edinburgh-Cape or Palomar-Green surveys, and 81 have |b| > 25°. The majority of the data come from previously existing spectroscopy, although also included are 18 new observations of stars with echelle spectra taken with UVES on the

J. V. Smoker; W. R. J. Rolleston; H. R. M. Kay; D. Kilkenny; R. Morras; M. Arnal; F. P. Keenan; C. J. Mooney; P. L. Dufton; R. S. I. Ryans; N. C. Hambly; D. O'Donoghue; H. McGillivray

2003-01-01

160

Swift and Fermi Observations of the Early Afterglow of the Short Gamma-Ray Burst 090510  

Microsoft Academic Search

We present the observations of GRB090510 performed by the Fermi Gamma-Ray Space Telescope and the Swift observatory. This is a bright, short burst that shows an extended emission detected in the GeV range. Furthermore, its optical emission initially rises, a feature so far observed only in long bursts, while the X-ray flux shows an initial shallow decrease, followed by a

M. De Pasquale; P. Schady; N. P. M. Kuin; M. J. Page; P. A. Curran; S. Zane; S. R. Oates; S. T. Holland; A. A. Breeveld; E. A. Hoversten; G. Chincarini; D. Grupe; A. A. Abdo; M. Ackermann; M. Ajello; M. Axelsson; L. Baldini; J. Ballet; G. Barbiellini; M. G. Baring; D. Bastieri; K. Bechtol; R. Bellazzini; B. Berenji; E. Bissaldi; R. D. Blandford; E. D. Bloom; E. Bonamente; A. W. Borgland; A. Bouvier; J. Bregeon; A. Brez; M. S. Briggs; M. Brigida; P. Bruel; T. H. Burnett; S. Buson; G. A. Caliandro; R. A. Cameron; P. A. Caraveo; S. Carrigan; J. M. Casandjian; C. Cecchi; Ö. Çelik; A. Chekhtman; J. Chiang; S. Ciprini; R. Claus; J. Cohen-Tanugi; V. Connaughton; J. Conrad; C. D. Dermer; A. de Angelis; F. de Palma; B. L. Dingus; E. do Couto e. Silva; P. S. Drell; R. Dubois; D. Dumora; C. Farnier; C. Favuzzi; S. J. Fegan; G. Fishman; W. B. Focke; M. Frailis; Y. Fukazawa; S. Funk; P. Fusco; F. Gargano; D. Gasparrini; N. Gehrels; S. Germani; N. Giglietto; F. Giordano; T. Glanzman; G. Godfrey; J. Granot; J. Greiner; I. A. Grenier; J. E. Grove; L. Guillemot; S. Guiriec; A. K. Harding; M. Hayashida; E. Hays; D. Horan; R. E. Hughes; M. S. Jackson; G. Jóhannesson; A. S. Johnson; W. N. Johnson; T. Kamae; H. Katagiri; J. Kataoka; N. Kawai; M. Kerr; R. M. Kippen; J. Knödlseder; D. Kocevski; M. Kuss; J. Lande; L. Latronico; M. Lemoine-Goumard; F. Longo; F. Loparco; B. Lott; M. N. Lovellette; P. Lubrano; A. Makeev; M. N. Mazziotta; J. E. McEnery; S. McGlynn; C. Meegan; P. Mészáros; C. Meurer; P. F. Michelson; W. Mitthumsiri; T. Mizuno; C. Monte; M. E. Monzani; E. Moretti; A. Morselli; I. V. Moskalenko; S. Murgia; P. L. Nolan; J. P. Norris; E. Nuss; M. Ohno; T. Ohsugi; N. Omodei; E. Orlando; J. F. Ormes; W. S. Paciesas; D. Paneque; J. H. Panetta; D. Parent; V. Pelassa; M. Pepe; M. Pesce-Rollins; F. Piron; T. A. Porter; R. Preece; S. Rainò; R. Rando; M. Razzano; A. Reimer; O. Reimer; T. Reposeur; S. Ritz; L. S. Rochester; A. Y. Rodriguez; M. Roth; F. Ryde; H. F.-W. Sadrozinski; A. Sander; P. M. Saz Parkinson; J. D. Scargle; T. L. Schalk; C. Sgrò; E. J. Siskind; P. D. Smith; G. Spandre; P. Spinelli; M. Stamatikos; J.-L. Starck; F. W. Stecker; M. S. Strickman; D. J. Suson; H. Tajima; H. Takahashi; T. Tanaka; J. B. Thayer; J. G. Thayer; D. J. Thompson; L. Tibaldo; K. Toma; D. F. Torres; G. Tosti; A. Tramacere; Y. Uchiyama; T. Uehara; T. L. Usher; A. J. van der Horst; V. Vasileiou; N. Vilchez; V. Vitale; A. von Kienlin; A. P. Waite; P. Wang; B. L. Winer; K. S. Wood; X. F. Wu; R. Yamazaki; T. Ylinen; M. Ziegler

2010-01-01

161

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

162

Early afterglow evolution of x-ray flashes observed by Swift  

NASA Astrophysics Data System (ADS)

Gamma-ray bursts (GRBs) are bright flashes of gamma-ray energy that originate in distant galaxies and last only a matter of seconds before fading away, never to appear again. They are accompanied by longer-wavelength "afterglows" that fade away much more gradually and can be detected for up to several days or even weeks after the gamma-ray burst has vanished. In recent years, another phenomenon has been discovered that resembles gamma- ray bursts in almost every way, except that the radiated energy comes mostly from x-rays instead of gamma-rays. This new class of bursts has been dubbed"x- ray flashes" (XRFs). There is strong evidence to suggest that GRBs and XRFs are closely-related phenomena. The Swift mission, launched in November of 2004, is designed to answer many questions about GRBs and their cousins, XRFs---where they come from, what causes them, and why gamma-ray bursts and x-ray flashes differ. The key to the Swift mission is its ability to detect and determine the location of a burst in the sky and then autonomously point x-ray and optical telescopes at the burst position within seconds of the detection. This allows the measurement of the afterglow within 1--2 minutes after the burst, rather than several hours later, as was necessary with past missions. This early afterglow measurement is an important key to distinguishing between different theories that seek to explain the differences between XRFs and GRBs. This dissertation describes the calibration of the Burst Alert Telescope, which measures the spectral and temporal properties of GRBs and XRFs. It also presents a study of XRFs and GRBs detected by Swift, including the first analysis and comparison of the early afterglow properties of these phenomena. This study reveals interesting differences between the temporal properties of GRB and XRF afterglows and sets strong constraints on some theories that seek to explain XRF origins.

Hullinger, Derek

2006-06-01

163

Decompositional reasoning about the history of parallel processes  

Microsoft Academic Search

Decompositional reasoning aims at automatically decompos- ing a global property of a composite system into local properties of (pos- sibly unknown) components. In concurrency theory, decompositional rea- soning techniques date back to the seminal work of Larsen and Liu in the late 1980s and early 1990s. However, we are not aware of any such de- composition technique that applies to

Luca Aceto; Arnar Birgisson; A Ingólfsdóttir; MohammadReza Mousavi

2012-01-01

164

Observation of the prompt and early afterglow of GRB 050904 by TAROT  

SciTech Connect

We present the recent observation of the very high redshift burst source GRB 050904 made by the TAROT robotized telescope. We have compared our data with the SWIFT XRT light curve to analyze the broad ban spectrum. We show that the luminosity and the behavior of this event is comparable with that of GRB 990123, suggesting the existence of very bright events. They can be detected at very high redshifts, even with small or moderate aperture telescopes, and they may constitute a powerful means for the exploration of the young universe. An update of the last TAROT observations performed as a response from SWIFT alerts is made.

Boeer, M.; Damerdji, Y. [Observatoire de Haute Provence, 04870 Saint Michel l'Observatoire (France); Atteia, J. L.; Stratta, G. [LATT-OMP, 14, ave. E. Belin, 31400 Toulouse (France); Gendre, B. [IASF/INAF, via fosso del cavaliere 100, 00133 Rome (Italy); Klotz, A. [Observatoire de Haute Provence, 04870 Saint Michel l'Observatoire (France); CESR, CNRS/UPS, BP 4346, 31029 Toulouse (France)

2006-05-19

165

SWIFT AND FERMI OBSERVATIONS OF THE EARLY AFTERGLOW OF THE SHORT GAMMA-RAY BURST 090510  

SciTech Connect

We present the observations of GRB090510 performed by the Fermi Gamma-Ray Space Telescope and the Swift observatory. This is a bright, short burst that shows an extended emission detected in the GeV range. Furthermore, its optical emission initially rises, a feature so far observed only in long bursts, while the X-ray flux shows an initial shallow decrease, followed by a steeper decay. This exceptional behavior enables us to investigate the physical properties of the gamma-ray burst outflow, poorly known in short bursts. We discuss internal and external shock models for the broadband energy emission of this object.

De Pasquale, M.; Schady, P.; Kuin, N. P. M. [Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking Surrey, RH5 6NT (United Kingdom)], E-mail: mdp@mssl.ucl.ac.uk (and others)

2010-02-01

166

Development of the action observation network during early adolescence: a longitudinal study  

PubMed Central

Adolescence places high demands on inter-personal interactions and, hence, on the extraction and processing of social cues. Here we assess longitudinally the development of brain activity within a network implicated in social cognition—the action observation network. We performed activation likelihood estimation meta-analyses to define regions of interest based upon the mature action observation network of adults. Using functional magnetic resonance imaging, we then examined developmental trajectories of functional brain activity within these brain regions. Using this approach, we reveal quadratic trajectories within a fronto-parietal network previously shown to demonstrate correlated morphological development.

Shaw, Daniel J.; Grosbras, Marie-Helene; Leonard, Gabriel; Pike, G. Bruce

2012-01-01

167

Swift and Fermi Observations of the Early Afterglow of the Short Gamma-Ray Burst 090510  

NASA Astrophysics Data System (ADS)

We present the observations of GRB090510 performed by the Fermi Gamma-Ray Space Telescope and the Swift observatory. This is a bright, short burst that shows an extended emission detected in the GeV range. Furthermore, its optical emission initially rises, a feature so far observed only in long bursts, while the X-ray flux shows an initial shallow decrease, followed by a steeper decay. This exceptional behavior enables us to investigate the physical properties of the gamma-ray burst outflow, poorly known in short bursts. We discuss internal and external shock models for the broadband energy emission of this object.

De Pasquale, M.; Schady, P.; Kuin, N. P. M.; Page, M. J.; Curran, P. A.; Zane, S.; Oates, S. R.; Holland, S. T.; Breeveld, A. A.; Hoversten, E. A.; Chincarini, G.; Grupe, D.; Abdo, A. A.; Ackermann, M.; Ajello, M.; Axelsson, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Baring, M. G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Bissaldi, E.; Blandford, R. D.; Bloom, E. D.; Bonamente, E.; Borgland, A. W.; Bouvier, A.; Bregeon, J.; Brez, A.; Briggs, M. S.; Brigida, M.; Bruel, P.; Burnett, T. H.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Carrigan, S.; Casandjian, J. M.; Cecchi, C.; Çelik, Ö.; Chekhtman, A.; Chiang, J.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Connaughton, V.; Conrad, J.; Dermer, C. D.; de Angelis, A.; de Palma, F.; Dingus, B. L.; Silva, E. do Couto e.; Drell, P. S.; Dubois, R.; Dumora, D.; Farnier, C.; Favuzzi, C.; Fegan, S. J.; Fishman, G.; Focke, W. B.; Frailis, M.; Fukazawa, Y.; Funk, S.; Fusco, P.; Gargano, F.; Gasparrini, D.; Gehrels, N.; Germani, S.; Giglietto, N.; Giordano, F.; Glanzman, T.; Godfrey, G.; Granot, J.; Greiner, J.; Grenier, I. A.; Grove, J. E.; Guillemot, L.; Guiriec, S.; Harding, A. K.; Hayashida, M.; Hays, E.; Horan, D.; Hughes, R. E.; Jackson, M. S.; Jóhannesson, G.; Johnson, A. S.; Johnson, W. N.; Kamae, T.; Katagiri, H.; Kataoka, J.; Kawai, N.; Kerr, M.; Kippen, R. M.; Knödlseder, J.; Kocevski, D.; Kuss, M.; Lande, J.; Latronico, L.; Lemoine-Goumard, M.; Longo, F.; Loparco, F.; Lott, B.; Lovellette, M. N.; Lubrano, P.; Makeev, A.; Mazziotta, M. N.; McEnery, J. E.; McGlynn, S.; Meegan, C.; Mészáros, P.; Meurer, C.; Michelson, P. F.; Mitthumsiri, W.; Mizuno, T.; Monte, C.; Monzani, M. E.; Moretti, E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nolan, P. L.; Norris, J. P.; Nuss, E.; Ohno, M.; Ohsugi, T.; Omodei, N.; Orlando, E.; Ormes, J. F.; Paciesas, W. S.; Paneque, D.; Panetta, J. H.; Parent, D.; Pelassa, V.; Pepe, M.; Pesce-Rollins, M.; Piron, F.; Porter, T. A.; Preece, R.; Rainò, S.; Rando, R.; Razzano, M.; Reimer, A.; Reimer, O.; Reposeur, T.; Ritz, S.; Rochester, L. S.; Rodriguez, A. Y.; Roth, M.; Ryde, F.; Sadrozinski, H. F.-W.; Sander, A.; Saz Parkinson, P. M.; Scargle, J. D.; Schalk, T. L.; Sgrò, C.; Siskind, E. J.; Smith, P. D.; Spandre, G.; Spinelli, P.; Stamatikos, M.; Starck, J.-L.; Stecker, F. W.; Strickman, M. S.; Suson, D. J.; Tajima, H.; Takahashi, H.; Tanaka, T.; Thayer, J. B.; Thayer, J. G.; Thompson, D. J.; Tibaldo, L.; Toma, K.; Torres, D. F.; Tosti, G.; Tramacere, A.; Uchiyama, Y.; Uehara, T.; Usher, T. L.; van der Horst, A. J.; Vasileiou, V.; Vilchez, N.; Vitale, V.; von Kienlin, A.; Waite, A. P.; Wang, P.; Winer, B. L.; Wood, K. S.; Wu, X. F.; Yamazaki, R.; Ylinen, T.; Ziegler, M.

2010-02-01

168

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

169

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

170

The Early Development of Object Knowledge: A Study of Infants' Visual Anticipations during Action Observation  

ERIC Educational Resources Information Center

|This study examined the developing object knowledge of infants through their visual anticipation of action targets during action observation. Infants (6, 8, 12, 14, and 16 months) and adults watched short movies of a person using 3 different everyday objects. Participants were presented with objects being brought either to a correct or to an…

Hunnius, Sabine; Bekkering, Harold

2010-01-01

171

The Early Development of Object Knowledge: A Study of Infants' Visual Anticipations during Action Observation  

ERIC Educational Resources Information Center

This study examined the developing object knowledge of infants through their visual anticipation of action targets during action observation. Infants (6, 8, 12, 14, and 16 months) and adults watched short movies of a person using 3 different everyday objects. Participants were presented with objects being brought either to a correct or to an…

Hunnius, Sabine; Bekkering, Harold

2010-01-01

172

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

National Technical Information Service (NTIS)

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 li...

G. D. Holman J. W. Brosius

2010-01-01

173

The accelerations of the earth and moon from early astronomical observations  

Microsoft Academic Search

An investigation has compiled a very large amount of data on central or near central solar eclipses as recorded in four principal ancient sources (Greek and Roman classics, medieval European chronicles, Chinese annals and astronomical treatises, and Late Babylonian astronomical texts) and applied careful data selectivity criteria and statistical methods to obtain reliable dates, magnitudes, and places of observation of

P. M. Muller; F. R. Stephenson

1975-01-01

174

Educative Experiences and Early Childhood Science Education: A Deweyan Perspective on Learning to Observe  

ERIC Educational Resources Information Center

|This paper is a report of work conducted at an urban elementary professional development school in the eastern US. John Dewey's explication of "educative experiences" is applied to describe curriculum involving small animals as a basis for teaching science inquiry processes, particularly the process of observation. The analysis is qualitative and…

Howes, Elaine V.

2008-01-01

175

Early Ice Formation in Tropical Maritime Convection Observed during the Ice in Clouds-Tropical Experiment  

NASA Astrophysics Data System (ADS)

During the Ice in Clouds Experiment-Tropical (ICE-T) in July 2011, the NSF/NCAR C130 aircraft flew thirteen research missions into towering cumulus thru cumulonimbus clouds in the vicinity of the Virgin Islands in the Caribbean. The primary goal of ICE-T is to understand how the first ice particles originate and impact the subsequent spread of the ice in clouds from this climatologically important region. ICE-T provided detailed aerosol and microphysical measurements of the interactions of episodic Saharan dust events with tropical cumuli. The C130 was equipped with a complement of cloud particle probes sizing from micron to cm sizes, online and offline chemical composition measurements of the residuals of evaporated droplets and ice particles, aerosol, cloud condensation and ice nuclei (aerosol and cloud residuals) spectral measurements, and upward and downward viewing Doppler cloud radar and lidar. The C130 observations focus on the critical temperature range from 0 to -10C, where primary nucleation on a few ice nuclei is thought to lead to a cascade of ice particles through subsequent secondary processes that are responsible for ice phase precipitation from these clouds and also affect the cloud dynamics. We will report on the in-situ observations from the C130,, drawing upon remote sensing observations where possible to provide context. Primary ice nucleation and secondary processes will be discussed in relation to our observations in this important class of clouds.

Heymsfield, A.; Field, P.; Lasher-Trapp, S.; Wang, Z.; French, J.; Haimov, S.; Leon, D.; Rogers, D.; Stith, J.; Demott, P.; Prather, K.

2012-04-01

176

Early atherogenesis in White Carneau pigeons. II. Ultrastructural and cytochemical observations.  

PubMed Central

The addition of cholesterol (0.5%) to the diet of White Carneau pigeons induces site specific, temporally predictable, atherosclerotic lesions. The earliest lesions, which occurred after 3 weeks, were small (less than 2500 sq mu in surface area) and were composed primarily of macrophage foam cells (94% of lesion volume). With a prolonged time on the diet the lesions expanded due to increases in the number and size of foam cells, increases in the amount of extracellular space, and influx of smooth muscle cells. Macrophage foam cells in advanced lesions composed 61% of the lesion volume, smooth muscle cells 25%, and extracellular space 14%. Concurrent with the alteration in the constituency of the lesion, redistribution of lipid within foam cells was noted. Lipid in small lesions was primarily cytoplasmic (88%), with the remaining 12% in acid-phosphatase-positive secondary lysosomes. In more advanced lesions, 34% of the lipid was cytoplastic and 66% was lysosomal. The changes in large lesions appeared to be a function of lesion age, because at the growing edge of large lesions both composition and lipid distribution resembled those of small early lesions. Images Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11

Jerome, W. G.; Lewis, J. C.

1985-01-01

177

Childhood Maltreatment and Prospectively Observed Quality of Early Care as Predictors of Antisocial Personality Disorder Features.  

PubMed

Few studies have evaluated the separate contributions of maltreatment and ongoing quality of parent-child interaction to the etiology of antisocial personality features using a prospective longitudinal design. 120 low-income young adults (aged 18-23) were assessed for extent of ASPD features on the Structured Clinical Interview for Diagnosis-Axis II, for presence of maltreatment on the Conflict Tactics Scale, Traumatic Experiences Scale, and Adult Attachment Interview, and for referral in infancy to parent-infant clinical services. Fifty-six of these families had been studied longitudinally since the first year of life. In infancy, attachment disorganization and disrupted mother-infant interaction were assessed; in middle childhood, disorganized-controlling attachment behaviors were reliably rated. In kindergarten and second grade, behavior problems were assessed by teacher report. In cross-sectional analyses, maltreatment was significantly associated with ASPD features but did not account for the independent effect of early referral to parent-infant services on ASPD features. In longitudinal analyses, maternal withdrawal in infancy predicted the extent of ASPD features twenty years later, independently of childhood abuse. In middle childhood, disorganized attachment behavior and maladaptive behavior at school added to prediction of later ASPD features. Antisocial features in young adulthood have precursors in the minute-to-minute process of parent-child interaction beginning in infancy. PMID:22754051

Shi, Zhenyu; Bureau, Jean-Francois; Easterbrooks, M Ann; Zhao, Xudong; Lyons-Ruth, Karlen

2012-01-23

178

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

179

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

180

Implementing the Bedside Paediatric Early Warning System in a community hospital: A prospective observational study  

PubMed Central

BACKGROUND: Late transfer of children with critical illness from community hospitals undermines the advantages of community-based care. It was hypothesized that implementation of the Bedside Paediatric Early Warning System (Bedside PEWS) would reduce late transfers. METHODS: A prospective before-and-after study was performed in a community hospital 22-bed inpatient paediatric ward. The primary outcome, significant clinical deterioration, was a composite measure of circulatory and respiratory support before transfer. Secondary outcomes were stat calls and resuscitation team calls, paediatrician workload and perceptions of frontline staff. RESULTS: Care was evaluated for 842 patient-days before and 2350 patient-days after implementation. The median inpatient census was 13. Implementation of the Bedside PEWS was associated with fewer stat calls to paediatricians (22.6 versus 5.1 per 1000 patient-days; P<0.0001), fewer significant clinical deterioration events (2.4 versus 0.43 per 1000 patient-days; P=0.013), reduced apprehension when calling the physician and no change in paediatrician workload. DISCUSSION: Implementation of the Bedside PEWS is feasible and safe, and may improve clinical outcomes.

Parshuram, Christopher S; Bayliss, Ann; Reimer, Janette; Middaugh, Kristen; Blanchard, Nadeene

2011-01-01

181

Microscopic observations of the early development of Pleurotus pulmonarius fruit bodies.  

PubMed

From observations made by light microscopy, transmission electron microscopy, environmental-scanning and cryoscanning electron microscopy we conclude that the expansion of the young fruit body of Pleurotus pulmonarius involves considerable vacuolation of hyphae but no marked inflation of cell dimensions. There is evidence for an extensive extracellular matrix (ECM), the components of which must be under the control of the hyphae which the ECM surrounds. However the ECM in these fruit bodies is a dilute material. It is easily lost during specimen preparation and is evident only when certain techniques are used to preserve the fluid surface of the hyphae. Observations of the hyphal and fruit body structures with a range of conventional microscopic techniques are crucial to complement the information obtained through physiological and molecular studies for understanding the cellular changes that occur during mushroom development. PMID:17256572

Sánchez, Carmen; Moore, David; Díaz-Godínez, Gerardo

182

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

183

A novel RO ex situ scale observation detector (EXSOD) for mineral scale characterization and early detection  

Microsoft Academic Search

A novel RO ex situ scale observation detector (EXSOD) was developed for direct visual real-time monitoring of mineral surface scaling on RO membranes. This system consists of a plate-and-frame RO cell with an optical window capable of withstanding pressures in excess of 2.4MPa. Membrane surface imaging under RO operation is accomplished by high resolution digital photography using an optical microscope

Michal Uchymiak; Anditya Rahardianto; Eric Lyster; Julius Glater; Yoram Cohen

2007-01-01

184

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

NASA Astrophysics Data System (ADS)

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 ?-ray emission with an average flux of ~3 × 10-6 photons cm-2 s-1, for energies >100 MeV. The ?-ray flux is variable, with strong, distinct, symmetrically shaped flares for which the flux increases by a factor of several on a timescale of about 3 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 ?>8, consistent with the values inferred from Very Long Baseline Interferometry observations of superluminal expansion (? ~ 25). The observed ?-ray spectrum is not consistent with a simple power law, but instead steepens strongly above ~2 GeV, and is well described by a broken power law with photon indices of ~2.3 and ~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 2 GeV could be due to ?-ray absorption via photon-photon pair production on the soft X-ray photon field of the host active galactic nucleus, but such an interpretation would require the dissipation region to be located very close (lsim100 gravitational radii) to the black hole, which would be inconsistent with the X-ray spectrum of the source.

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

2009-07-01

185

Partially observable Markov decision model for the treatment of early Prostate Cancer  

Microsoft Academic Search

Prostate cancer is second only to lung cancer as the leading cause of cancer deaths in the world Furthermore, policies are\\u000a difficult to make because of the generally indolent nature of prostate cancer and because it tends to occur in older men who\\u000a often have multiple, competing medical illnesses. In this paper we applied a Partially observable Markov decision processes

John E. Goulionis; B. K. Koutsiumaris

2010-01-01

186

Spinodal Decomposition in Soda-Silica Glass.  

National Technical Information Service (NTIS)

The early and later stage kinetics of phase separation in the unstable region where spinodal decomposition may occur, was investigated in the Na2O-SiO2 system. Two compositions having differing initial quench histories were studied. Small angle x-ray scat...

G. F. Neilson

1969-01-01

187

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

188

A word of the Empirics: the ancient concept of observation and its recovery in early modern medicine.  

PubMed

The genealogy of observation as a philosophical term goes back to the ancient Greek astronomical and medical traditions, and the revival of the concept in the Renaissance also happened in the astronomical and medical context. This essay focuses primarily on the medical genealogy of the concept of observation. In ancient Greek culture, an elaboration of the concept of observation (t?r?sis) first emerged in the Hellenistic age with the medical sect of the Empirics, to be further developed by the ancient Sceptics. Basically unknown in the Middle Ages, the Empirics' conceptualisation of t?r?sis trickled back into Western medicine in the fourteenth century, but its meaning seems to have been fully recovered by European scholars only in the 1560s, concomitantly with the first Latin translation of the works of Sextus Empiricus. As a category originally associated with medical Scepticism, observatio was a new entry in early modern philosophy. Although the term gained wide currency in general scholarly usage in the seventeenth century, its assimilation into standard philosophical language was very slow. In fact, observatio does not even appear as an entry in the philosophical dictionaries until the eighteenth century--with one significant exception, the medical lexica, which featured the lemma, reporting its ancient Empiric definition, as early as 1564. PMID:21466002

Pomata, Gianna

2011-01-01

189

Solving Decomposition Problems: Alternative Techniques and Description of Supporting Tools.  

National Technical Information Service (NTIS)

An interactive software system specially designed to solve the kind of set decomposition problems that arise in the investigation of a systematic approach for the early phases of the system development process is presented. Traditional cluster analytic al...

R. C. Andreu

1977-01-01

190

EARLY CHROMOSPHERIC RESPONSE DURING A SOLAR MICROFLARE OBSERVED WITH SOHO's CDS AND RHESSI  

SciTech Connect

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 ({approx}-200 km s{sup -1}) 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. [Catholic University of America at NASA Goddard Space Flight Center, Solar Physics Laboratory, Code 671, Greenbelt, MD 20771 (United States); Holman, Gordon D., E-mail: Jeffrey.W.Brosius@nasa.go, E-mail: Gordon.D.Holman@nasa.go [NASA Goddard Space Flight Center, Solar Physics Laboratory, Code 671, Greenbelt, MD 20771 (United States)

2010-09-10

191

A study of phase decomposition in Cu-Ni-Fe alloys  

SciTech Connect

A study of phase decomposition in two Cu-Ni-Fe alloys was realized by AP-FIM. It was possible to confirm that phase decomposition takes place via spinodal decomposition in this alloy system, as the amplitude of the composition modulation increased with aging time without practically any change in the wavelength of the modulation. It was also observed that the morphology of the decomposed phases is related to the coherency-strain energy as predicted by Cahn's theory of spinodal decomposition. By analysis of the data of the modulation wavelength, it was possible to estimate the coherent spinodal temperature to be 800 [plus minus] 25 and 900 [plus minus] 25K in Cu-46 at.% Ni-4 at.% Fe and Cu-48 at.% Ni-8 at.% Fe alloys, respectively. In the early stage of decomposition, the change in modulation wavelength showed a time exponent as small as about 0.07. On the other hand, in the coarsening stage the change in the modulation wavelength agreed well with the LSW theory of thermally activated growth. The activation energy for this coarsening process was determined to be 216 [plus minus] 10 and 232 [plus minus] 10 kJ/mol in the Cu-46 at.% Ni-4 at.% Fe and Cu-48 at.% Ni-8 at.% Fe alloys, respectively. The compositions of the decomposed phases are consistent with the miscibility gap in the calculated equilibrium Cu-Ni-Fe phase diagram.

Lopez, H.V.M.; Sakurai, T.; Hirano, K. (Univ. of Tohoku, Sendai (Japan). Dept. of Materials Science); Sano, N. (Univ. of Tokyo, Tokyo (Japan). Inst. for Solid State Physics)

1993-01-01

192

The Early History of Photometric Observations of Asteroids made at the Table Mountain Observatory  

NASA Astrophysics Data System (ADS)

An Ascop S-20 photomultiplier tube mounted in a Mt. Wilson designed dry-ice cold-box assembly was used with a pulse-counting system to measure the colors, magnitudes, rotational rates, and phase coefficients of over 300 different asteroids between 1978 and 1993. During this time period, nearly one third of all known asteroid rotational rates (~150) were obtained from this effective system. All observations were made with manual telescopic pointing, with data written out long-hand utilizing the 0.6 meter telescope at JPL's Table Mountain Facility. Nearly 40 refereed journal (mostly ICARUS) papers were published containing these results, with yet a few more to come.

Young, James W.; Harris, Alan W.

2009-05-01

193

Methanethiol decomposition on Ni(100)  

SciTech Connect

Static secondary ion mass spectroscopy (SSIMS), temperature programmed desorption (TPD), and Auger electron spectroscopy (AES) were used under ultrahigh vacuum conditions to study the decomposition of CH{sub 3}SH on Ni(100). Only methane, hydrogen, and the parent molecule are observed in TPD. Complete decomposition to C(a), S(a) and desorbing H{sub 2} is the preferred reaction pathway for low exposures, while desorption of methane is observed at higher coverages. Preadsorbed hydrogen promoted methane desorption. Upon adsorption, and for low coverages, SSIMS evidence indicates S-H bond cleavage into CH{sub 3}S and surface hydrogen. S-H bond cleavage is inhibited for high coverages. The TP-SSIMS data are consistent with an activated C-S bond cleavage in CH{sub 3}S, with an activation energy of 8.81 kcal/mol and preexponential factor of 10{sup 6.5}s{sup {minus}1}. The low preexponential factor is taken as indicating a complex decomposition pathway. A mechanism consistent with the observed data is discussed.

Castro, M.E.; Ahkter, S.; Golchet, A.; White, J.M. (Univ. of Texas, Austin (USA)); Sahin, T. (Montana State Univ., Bozeman (USA))

1991-01-01

194

A Multistage Position\\/Force Control for Constrained Robotic Systems With Friction: Joint-Space Decomposition, Linearization, and Multiobjective Observer\\/Controller Synthesis Using LMI Formalism  

Microsoft Academic Search

A historical review of constrained robot modeling and control strategies is first introduced. Next, a design of a motion\\/force controller for a constrained servo-robot, which is based on a commonly known modeling structure, is proposed. The contact between the end-effector and the environment is subject to frictional features. Accordingly, the control plant is based on the LuGre friction closed-loop observer.

Karim Khayati; Pascal Bigras; L.-A. Dessaint

2006-01-01

195

A SOLAR CYCLE LOST IN 1793-1800: EARLY SUNSPOT OBSERVATIONS RESOLVE THE OLD MYSTERY  

SciTech Connect

Because of the lack of reliable sunspot observations, the quality of the sunspot number series is poor in the late 18th century, leading to the abnormally long solar cycle (1784-1799) before the Dalton minimum. Using the newly recovered solar drawings by the 18-19th century observers Staudacher and Hamilton, we construct the solar butterfly diagram, i.e., the latitudinal distribution of sunspots in the 1790s. The sudden, systematic occurrence of sunspots at high solar latitudes in 1793-1796 unambiguously shows that a new cycle started in 1793, which was lost in the traditional Wolf sunspot series. This finally confirms the existence of the lost cycle that has been proposed earlier, thus resolving an old mystery. This Letter brings the attention of the scientific community to the need of revising the sunspot series in the 18th century. The presence of a new short, asymmetric cycle implies changes and constraints to sunspot cycle statistics, solar activity predictions, and solar dynamo theories, as well as for solar-terrestrial relations.

Usoskin, Ilya G. [Sodankylae Geophysical Observatory (Oulu unit), University of Oulu (Finland); Mursula, Kalevi [Department of Physical Sciences, University of Oulu (Finland); Arlt, Rainer [Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam (Germany); Kovaltsov, Gennady A. [Ioffe Physical-Technical Institute of RAS, 194021 St. Petersburg (Russian Federation)], E-mail: ilya.usoskin@oulu.fi

2009-08-01

196

The sealed osteons of cortical diaphyseal bone. Early observations revisited with scanning electron microscopy.  

PubMed

The frequency, structure, mode of formation and significance of sealed osteons remain unsettled. Sealed osteons have been reported as an unusual finding in the cortical bone of experimental animals: we extended the observation to human cortical bone studied with SEM. Tibial bone specimens from three patients who sustained a traumatic below-the-knee amputation were used in the study. The observed total mean density of osteons was 19.25/mm(2) and the percentage of sealed and partially sealed osteons was 4.2% and 1.7% respectively. The material sealing the central canal showed an X-ray microanalysis spectrum with the same Ca/P ratio as the peripheral lamellae and a lower carbon signal. The morphology suggested a reactivation of bone apposition triggered by exclusion of the occluded canal from blood flow rather than a physiological evolution of the closing process of secondary osteons. This presupposes collapse and degeneration of the central vessel before the osteoblasts resting on the inner surface of the canal could start to lay down new bone matrix. This explanation is consistent with a dynamic model of intracortical blood flow. PMID:21234993

Congiu, Terenzio; Pazzaglia, Ugo E

2010-12-03

197

High-resolution observations of tungsten liner collapse and early jet formation  

SciTech Connect

High-resolution photography of collapsing tungsten-lined shaped charges has revealed surface texturing both similar to and strikingly different from that previously observed during copper liner collapse. The behavior of three types of tungsten-lined shaped charges, with different liner designs and high explosives but with similar tungsten processing, were characterized by image-converter camera and fast- framing camera photography, and flash x-ray radiography. 120-mm- diameter, trumpet-shaped Octol charges produced surface blistering near the base of the tungsten liner, probably due to inhomogeneities near the liner-explosive interface resulting from cast loading. 148- mm-diameter, quasi-conical LX-14 charges produced smooth shocked- surface texture similar to that observed in conical, copper-lined LX- 14 (Viper) charges. 81-mm-diameter, conical LX-20 charges produced severe radial texturing throughout the collapsing tungsten liner, which transitioned to azimuthal banding on the jet surface. For each type of charge, obscuring debris from the tungsten jet tip prevented clear imaging of the jet surface at late time. 8 refs., 6 figs., 2 tabs.

Winer, K.A.; Breithaupt, R.D.; Muelder, S.A.; Baum, D.W.

1996-07-01

198

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 components which influence NaTPB decomposition. Copper(II) ions, solution temperature, and solution pH (hydroxide ion concentration) have all been demonstrated to affect NaTPB stability. Their relationship with each other and the stability of NaTPB has been determined. Based upon this knowledge, a method for stabilizing NaTPB was determined. Decomposition of a NaTPB solution was delayed with the addition of sodium hydroxide. In additional work, the elimination of oxygen from the reaction environment did not prevent NaTPB decomposition in the presence of copper(II) ions but did, however, affect the course of decomposition.

Barnes, M.J.

1990-01-01

199

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 components which influence NaTPB decomposition. Copper(II) ions, solution temperature, and solution pH (hydroxide ion concentration) have all been demonstrated to affect NaTPB stability. Their relationship with each other and the stability of NaTPB has been determined. Based upon this knowledge, a method for stabilizing NaTPB was determined. Decomposition of a NaTPB solution was delayed with the addition of sodium hydroxide. In additional work, the elimination of oxygen from the reaction environment did not prevent NaTPB decomposition in the presence of copper(II) ions but did, however, affect the course of decomposition.

Barnes, M.J.

1990-12-31

200

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

201

The effect of anhydrite on oil production in dolomite reservoirs - Some early observations  

SciTech Connect

Results from wireline log analysis of recently drilled wells in the San Andres dolomite of the Slaughter and Levelland fields, west Texas, suggested a correlation between the presence of anhydrite and poor oil production. Log data from wells in the North-Central Levelland, Wright and Boyd Mallet units show that a high percentage of wells that perform poorly all have significant amounts of anhydrite in their reservoirs. Preliminary indications suggest that more than 20% anhydrite in the reservoir will severely reduce porosity and permeability and cause higher than average water saturations. In addition, the spacing of new wells indicates that reservoir degradation by anhydrite may be sporadic and areally restricted, allowing a poorly performing well to be located no more than 1500 ft from better performing wells that have low amounts of anhydrite. These observations imply that uneconomic infill well locations could be minimized by mapping the percent of anhydrite within the reservoir section. On a practical basis, the only way to acquire a sufficiently large enough database for good anhydrite prediction in west Texas is to refine log analysis to yield accurate mineralogy from cased hole logs.

Buza, J.W.; Gould, J.F. (Mobil Exploration and Producing U.S. Inc., Midland, TX (United States))

1992-04-01

202

Decomposition of hydrogen peroxide at elevated temperatures  

SciTech Connect

Decomposition of hydrogen peroxide in high-purity water has been measured at temperatures ranging from 100 to 280{degree}C in a laboratory test loop. A first-order decomposition kinetics has been observed in all cases, but the decomposition rates were found to vary widely, depending on the material used in the reaction chamber. In a 1/4 inch OD stainless steel tubing, the decomposition rate constant is estimated at 0.3 sec{sup {minus}1} at 280{degree}C and the activation energy is 15 Kcal/mol. This decomposition rate is approximately 100 times faster than that observed in a Teflon tubing. The variation of decomposition rate in different reaction chambers is attributed to the heterogeneous catalytic effects. Hydrogen peroxide is believed to decompose through free radical reactions involving a charge transfer process on material surfaces. It is also observed that there is some, but very little evidence of reaction between H{sub 2} and H{sub 2}O{sub 2} in high-purity water at temperatures up to 280{degree}C. Copper ions are found to significantly enhance the H{sub 2}O{sub 2} decomposition rate and catalyze the reaction between H{sub 2} and H{sub 2}O{sub 2}. The effects of H{sub 2}O{sub 2} on the electrochemical potentials (ECP) of stainless steel are also investigated (reported separately). Although the exact mechanism is not clear, the increase of ECP by H{sub 2}O{sub 2} may be easily explained by the charge transfer process on stainless steel surfaces which provide the catalytic media for the H{sub 2}O{sub 2} decomposition. Application of the test results obtained in this program in the water radiolysis model calculation for BWR hydrogen water chemistry is also discussed. 46 refs., 29 figs., 5 tabs.

Lin, C.C.; Smith, F.R. (General Electric Co., San Jose, CA (USA). Nuclear Energy Div.)

1990-03-01

203

Insight into the Early Evolution of Globular Clusters and Supermassive Black Holes from Panchromatic Observations of Nearby Dwarf Starburst Galaxies  

NASA Astrophysics Data System (ADS)

In the earlier universe, both globular clusters and the seeds of supermassive black holes are believed to have formed in the progenitors of modern massive galaxies, although the details are poorly understood. Direct observations of these low-mass, distant, and hence faint systems are unobtainable with current capabilities. However, gas-rich dwarf starburst galaxies in the local universe, analogous in many ways to protogalaxies at high-redshift, can provide critical insight into the early stages of galaxy evolution including the formation of globular clusters and massive black holes. We present a panchromatic study of nearby dwarf starburst galaxies harboring nascent globular clusters still embedded in their birth material. We also show the first example of a nearby dwarf starburst galaxy simultaneously hosting an actively accreting intermediate-mass central black hole and an extreme burst of star formation. The massive black hole in this dwarf galaxy is unusual in that it is not associated with a bulge, a nuclear star cluster, or any other well-defined nucleus, likely reflecting an early phase of black hole and galaxy evolution that has not been previously observed.

Reines, Amy E.

2011-01-01

204

Early Results from TNTCAM2, a Mid-IR Imaging Polarimeter, and Remote Internet Observing  

NASA Astrophysics Data System (ADS)

We present new science results from TNTCAM2 obtained at the WIRO 2.3 meter telescope. These include: (1) polarization maps of the BN object and a section of M42 around the Trapezium that shows bow shocks; (2) imaging and polarimetry of selected circumstellar shells of evolved stars and planetary nebulae; (3) new mid-IR photometry of ISO selected Vega-type stars showing a mid-infrared spectral energy excess, and (4) attempts to detect proplyds in Orion. The photometry and polarimetry of bright sources allows us to characterize the system performance in terms of throughput of the optics and net system sensitivity, which we compare to the sensitivity of TNTCAM1 at WIRO (S/N = 5 on an 8.0 magnitude 11.5? m source (20 mJy) over a 30 minutes of coadded .03s integrations). We also present the efficiency of the polarization analyzer and a comparison of our polarization measurments of selected bright objects with previous measurements in the mid-IR. We discuss and demonstrate the remote use of TNTCAM2 on the Wyoming Infra-Red Observatory (WIRO) telescope. The remote observer can connect to the observatory computers from a variety of operating systems using AT&T's Virtual Network Computing software. Remote real-time control of the telescope and TNTCAM2 have already been achieved from the University of Denver over a standard ethernet connection through WIRO's 10.5 Mbps microwave link. We thank Craig Smith for invaluable suggestions and guidance in collecting and reducing polarimetry data in the mid-IR. We acknowledge support under NSF grant AST-9724506 to the University of Denver and NASA EPSCoR grant #NCC5-414 to the University of Wyoming.

Theil, D. S.; Edwards, M. E.; Jurgenson, C. A.; Klebe, D. I.; Stencel, R. E.; Cash, J. L.; Martin, R. T.; Johnson, P. E.; Weger, J. S.

2001-05-01

205

Research capacity and culture in podiatry: early observations within Queensland Health  

PubMed Central

Background Research is a major driver of health care improvement and evidence-based practice is becoming the foundation of health care delivery. For health professions to develop within emerging models of health care delivery, it would seem imperative to develop and monitor the research capacity and evidence-based literacy of the health care workforce. This observational paper aims to report the research capacity levels of statewide populations of public-sector podiatrists at two different time points twelve-months apart. Methods The Research Capacity & Culture (RCC) survey was electronically distributed to all Queensland Health (Australia) employed podiatrists in January 2011 (n?=?58) and January 2012 (n?=?60). The RCC is a validated tool designed to measure indicators of research skill in health professionals. Participants rate skill levels against each individual, team and organisation statement on a 10-point scale (one?=?lowest, ten?=?highest). Chi-squared and Mann Whitney U tests were used to determine any differences between the results of the two survey samples. A minimum significance of p??6). Whereas, most reported their organisation’s skills to perform and support research at much higher levels (Median?>?6). The 2012 survey respondents reported significantly higher skill ratings compared to the 2011 survey in individuals’ ability to secure research funding, submit ethics applications, and provide research advice, plus, in their organisation’s skills to support, fund, monitor, mentor and engage universities to partner their research (p?

2013-01-01

206

Insect succession and carrion decomposition in selected forests of Central Europe. Part 1: Pattern and rate of decomposition.  

PubMed

Pig carrion decomposition and insect succession were monitored in different seasons and forests of Central Europe. Pattern of decomposition as well as onset, duration and rate of decompositional processes were measured. Pattern of decomposition was the same in almost all cases with putrefaction, active and advanced decay. In the majority of carcasses active decay was driven by larvae of Calliphoridae with a clear seasonal shift in dominant taxa. However, in some spring, alder forest cases active decay was driven by larvae of Necrodes littoralis (Coleoptera: Silphidae). As a rule the mosaic decomposition was observed. In spring a significant delay in onset of all decompositional processes was found. Season significantly affected rate of active decay due to a much higher rate in summer. Decomposition in alder forest proceeded faster than in pine-oak forest and hornbeam-oak forest. Differences between the latter two forests were practically negligible. Implications for forensic entomology are discussed. PMID:19914786

Matuszewski, Szymon; Bajerlein, Daria; Konwerski, Szymon; Szpila, Krzysztof

2009-11-14

207

Thermal decomposition of allylbenzene ozonide  

SciTech Connect

Thermal decomposition of allylbenzene ozonide (ABO) at 98{degree}C in the liquid phase yields toluene, bibenzyl, phenylacetaldehyde, formic acid, and (benzyloxy)methyl formate as major products; benzyl chloride is formed when chlorinated solvents are employed. These products, as well as benzyl formate, are formed when ABO is decomposed at 37{degree}C. When the decomposition of ABO is carried out in the presence of 1-butanethiol, the product distribution changes: yields of toluene increase, no bibenzyl is formed, and decreases in yields of (benzyloxy)methyl formate, phenylacetladehyde, and benzyl chloride are observed. The decomposition of 1-octene ozonide (OTO) also was studied for comparison. The activation parameters for both ABO and OTO are similar (28.2 kcal/mol, log A = 13.6 and 26.6 kcal/mol, log A = 12.5, respectively); these data suggest that ozonides decompose by homolysis of the O-O bond, rather than by an alternative synchronous two-bond scission process. When ABO is decomposed at 37{degree}C in the presence of the spin traps 5,5-dimethyl-1-pyrroline N-oxide (DMPO) or 3,3,5,5-tetramethyl-1-pyrroline N-oxide (M{sub 4}PO), ESR signals are observed that are consistent with the trapping of benzyl and other carbon- and oxygen-centered radicals. A mechanism for the thermal decomposition of ABO that involves peroxide bond homolysis and subsequent {beta}-scission is proposed. Thus, Criegee ozonides decompose to give free radicals at quite modest temperatures.

Ewing, J.C.; Church, D.F.; Pryor, W.A. (Louisiana State Univ., Baton Rouge (USA))

1989-07-19

208

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

209

SPITZER OBSERVATIONS OF PASSIVE AND STAR-FORMING EARLY-TYPE GALAXIES: AN INFRARED COLOR-COLOR SEQUENCE  

SciTech Connect

We describe the infrared properties of a large sample of early-type galaxies, comparing data from the Spitzer archive with Ks-band emission from the Two Micron All Sky Survey. While most representations of this data result in correlations with large scatter, we find a remarkably tight relation among colors formed by ratios of luminosities in Spitzer-Multiband Imaging Photometer bands (24, 70, and 160 mum) and the Ks band. Remarkably, this correlation among E and S0 galaxies follows that of nearby normal galaxies of all morphological types. In particular, the tight infrared color-color correlation for S0 galaxies alone follows that of the entire Hubble sequence of normal galaxies, roughly in order of galaxy type from ellipticals to spirals to irregulars. The specific star formation rate (SFR) of S0 galaxies estimated from the 24 mum luminosity increases with decreasing K-band luminosity (or stellar mass) from essentially zero, as with most massive ellipticals, to rates typical of irregular galaxies. Moreover, the luminosities of the many infrared-luminous S0 galaxies can significantly exceed those of the most luminous (presumably post-merger) E galaxies. SFRs in the most infrared-luminous S0 galaxies approach 1-10 solar masses per year. Consistently, with this picture we find that while most early-type galaxies populate an infrared red sequence, about 24% of the objects (mostly S0s) are in an infrared blue cloud together with late-type galaxies. For those early-type galaxies also observed at radio frequencies, we find that the far-infrared luminosities correlate with the mass of neutral and molecular hydrogen, but the scatter is large. This scatter suggests that the star formation may be intermittent or that similar S0 galaxies with cold gaseous disks of nearly equal mass can have varying radial column density distributions that alter the local and global SFRs.

Temi, Pasquale [Astrophysics Branch, NASA/Ames Research Center, MS 245-6, Moffett Field, CA 94035 (United States); Brighenti, Fabrizio; Mathews, William G., E-mail: pasquale.temi@nasa.go, E-mail: mathews@ucolick.or, E-mail: fabrizio.brighenti@unibo.i [University of California Observatories/Lick Observatory, Board of Studies in Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)

2009-12-20

210

Orthogonal tensor decompositions  

SciTech Connect

The authors explore the orthogonal decomposition of tensors (also known as multi-dimensional arrays or n-way arrays) using two different definitions of orthogonality. They present numerous examples to illustrate the difficulties in understanding such decompositions. They conclude with a counterexample to a tensor extension of the Eckart-Young SVD approximation theorem by Leibovici and Sabatier [Linear Algebra Appl. 269(1998):307--329].

Tamara G. Kolda

2000-03-01

211

Gauge- and frame-independent decomposition of nucleon spin  

SciTech Connect

In a recent paper, we have shown that the way of gauge-invariant decomposition of the nucleon spin is not necessarily unique, but there still exists a preferable decomposition from the observational viewpoint. What was not complete in this argument is a fully satisfactory answer to the following questions. Does the proposed gauge-invariant decomposition, especially the decomposition of the gluon total angular momentum into its spin and orbital parts, correspond to observables which can be extracted from high-energy deep-inelastic-scattering measurements? Is this decomposition not only gauge invariant but also Lorentz frame independent, so that it is legitimately thought to reflect an intrinsic property of the nucleon? We show that we can answer both of these questions affirmatively by making full use of a gauge-invariant decomposition of the covariant angular-momentum tensor of QCD in an arbitrary Lorentz frame.

Wakamatsu, M. [Department of Physics, Faculty of Science, Osaka University, Toyonaka, Osaka 560-0043 (Japan)

2011-01-01

212

Aflatoxin decomposition in various soils  

SciTech Connect

The persistence of aflatoxin in the soil environment could potentially result in a number of adverse environmental consequences. To determine the persistence of aflatoxin in soil, /sup 14/C-labeled aflatoxin B1, was added to silt loam, sandy loam, and silty clay loam soils and the subsequent release of /sup 14/CO/sub 2/ was determined. After 120 days of incubation, 8.1% of the original aflatoxin added to the silt loam soil was released as CO/sub 2/. Aflatoxin decomposition in the sandy loam soil proceeded more quickly than the other two soils for the first 20 days of incubation. After this time, the decomposition rate declined and by the end of the study, 4.9% of the aflatoxin was released as CO/sub 2/. Aflatoxin decomposition proceeded most slowly in the silty clay loam soil. Only 1.4% of aflatoxin added to the soil was released as CO/sub 2/ after 120 days incubation. To determine whether aflatoxin was bound to the silty clay loam soil, aflatoxin B1 was added to this soil and incubated for 20 days. The soil was periodically extracted and the aflatoxin species present were determined using thin layer chromatographic (TLC) procedures. After one day of incubation, the degradation products, aflatoxins B2 and G2, were observed. It was also found that much of the aflatoxin extracted from the soil was not mobile with the TLC solvent system used. This indicated that a conjugate may have formed and thus may be responsible for the lack of aflatoxin decomposition.

Angle, J.S.

1986-08-01

213

Decomposition of blackberry and broomsedge bluestem as influenced by ozone  

SciTech Connect

Many researchers have reported on individual plant responses to O{sub 3}, but few have investigated the effects of this pollutant on ecosystem function. This investigation examined the influence of O{sub 3} on short-term (Phase 1) litter decomposition of blackberry (Rubus cuneifolus Pursh.) and broomsedge bluestem (Andropogon virginicus L.), two plant species native to early successional forest communities in the southern US. Mixed blackberry/broomsedge litter (1:1) collected from plants exposed to different levels of O{sub 3} for one growing season was placed in open-top chambers and exposed to different O{sub 3} levels of treatments for 24 weeks. Litter also was incubated in microcosms in the laboratory t 25 or 30 C to determine the effects of climate change on O{sub 3}-treated litter. Initial C and N concentrations of the collected foliage did not differ significantly among treatments for either species. Blackberry litter had approximately twice as much N as broomsedge, and when collected from 2X O{sub 3} chambers, had significantly greater permanganate lignin than the other treatments. Initial permanganate lignin concentration of blackberry, over all O{sub 3} treatments, correlated significantly with remaining mass of the litter mixture after 24 wk exposure. Litter decomposed more slowly in the 2X chambers than in the other treatment chambers, regardless of litter source. Elevated O{sub 3}-exposed litter (2X) decomposed the slowest regardless of treatment applied. There were significant temperature and time effects observed with litter decomposition: litter incubated at 30 C decomposed faster than at 25 C. The data suggest O{sub 3} may influence substrate quality and microbial activity, thus reducing the rate of litter decomposition in early successional forest communities.

Kim, J.S. [Sunchon National Univ. (Korea, Republic of); Chappelka, A.H.; Miller-Goodman, M.S. [Auburn Univ., AL (United States)

1998-07-01

214

Goddard High-Resolution Spectrograph Observations of the B III Resonance Doublet in Early B Stars: Abundances and Isotope Ratios  

NASA Astrophysics Data System (ADS)

Boron abundances and isotope ratios in two early B stars have been measured by using the Hubble Space Telescope's Goddard High-Resolution Spectrograph (GHRS) in order to observe the B III resonance doublet near 2066 Å. We also report new experimental and theoretical results for the wavelengths, isotope shift, and hyperfine structure of these boron lines. In HD 886 (gamma Pegasi; B2 IV), and HD 35299 (B1 V) the abundance of boron is about a factor of 2 lower than that inferred from solar system meteorites. The ^11B/^10B isotope ratio in HD 886 is determined to be 4.7^+1.1_-1.0, and for HD 35299 a value of 3.7^+0.8_-0.6 is found. These values are consistent with the solar system isotope ratio. In a third star, HD 3360 (zeta Cassiopeiae; B2 IV), our GHRS observations show that the boron abundance is a factor of 40 below the solar system abundance. Our results for HD 886 and HD 35299 appear to be consistent with little dispersion in the initial boron-to-oxygen ratio among Population I stars and a universal ^11B/^10B isotope ratio. However, the abundance measured for HD 3360 shows that either some stars suffer significant boron depletion while still in the core-hydrogen burning phase of their evolution, or there is indeed a very wide variation in initial Population I boron abundances. A much-improved understanding of boron astration in early B stars will be required before this question can be resolved.

Proffitt, Charles R.; Jönsson, Per; Litzén, Ulf; Pickering, Juliet C.; Wahlgren, Glenn M.

1999-05-01

215

A Multilinear Singular Value Decomposition  

Microsoft Academic Search

We discuss a multilinear generalization of the singular value decomposition. There is a strong analogy between several properties of the matrix and the higher-order tensor decomposition; uniqueness, link with the matrix eigenvalue decomposition, first-order perturbation effects, etc., are analyzed. We investigate how tensor symmetries affect the decomposition and propose a multilinear generalization of the symmetric eigenvalue decomposition for pair-wise symmetric

Lieven De Lathauwer; Bart De Moor; Joos Vandewalle

2000-01-01

216

Heuristic Methods for Hypertree Decomposition  

Microsoft Academic Search

The literature provides several structural decomposition methods for identifying tractable subclasses of the constraint satisfaction\\u000a problem. Generalized hypertree decomposition is the most general of such decomposition methods. Although the relationship to other structural decomposition methods has\\u000a been thoroughly investigated, only little research has been done on efficient algorithms for computing generalized hypertree\\u000a decompositions. In this paper we propose new heuristic

Artan Dermaku; Tobias Ganzow; Georg Gottlob; Benjamin J. Mcmahan; Nysret Musliu; Marko Samer

2008-01-01

217

Efficient hydrogen peroxide decomposition on bimetallic Pt–Pd surfaces  

Microsoft Academic Search

Hydrogen peroxide was efficiently decomposed on Pt–Pd surface deposited on Nafion membrane. Comparing the activities for the different materials, the activity for the decomposition of hydrogen peroxide was found to decrease in the order of Pt–Pd surface>MnO2>K2Cr2O7>Au>Polycrystalline Pt plate. Kinetics and thermodynamics of the decomposition process were investigated. It was observed that the decomposition process followed bimolecular first order kinetics,

M. A. Hasnat; M. Maria Rahman; S. M. Borhanuddin; Ayesha Siddiqua; N. M. Bahadur; M. R. Karim

2010-01-01

218

CHANDRA OBSERVATIONS OF NGC 4342, AN OPTICALLY FAINT, X-RAY GAS-RICH EARLY-TYPE GALAXY  

SciTech Connect

Chandra x-ray observations of NGC 4342, a low-stellar mass (M{sub K} = -22.79 mag) early-type galaxy, show luminous, diffuse x-ray emission originating from hot gas with temperature of kT {approx} 0.6 keV. The observed 0.5-2 keV band luminosity of the diffuse x-ray emission within the D{sub 25} ellipse is L{sub 0.5-2keV} = 2.7 Multiplication-Sign 10{sup 39} erg s{sup -1}. The hot gas has a significantly broader distribution than the stellar light, and shows strong hydrodynamic disturbances with a sharp surface brightness edge to the northeast and a trailing tail. We identify the edge as a cold front and conclude that the distorted morphology of the hot gas is produced by ram pressure as NGC 4342 moves through external gas. From the thermal pressure ratios inside and outside the cold front, we estimate the velocity of NGC 4342 and find that it moves supersonically (M {approx} 2.6) toward the northeast. Outside the optical extent of the galaxy, we detect {approx}17 bright (L{sub 0.5-8keV} > or approx. 3 x 10{sup 37} erg s{sup -1}) excess x-ray point sources. The excess sources are presumably LMXBs located in metal-poor globular clusters (GCs) in the extended dark matter halo of NGC 4342. Based on the number of excess sources and the average frequency of bright LMXBs in GCs, we estimate that NGC 4342 may host roughly 850-1700 GCs. In good agreement with this, optical observations hint that NGC 4342 may harbor 1200 {+-} 500 GCs. This number corresponds to a GC specific frequency of S{sub N} = 19.9 {+-} 8.3, which is among the largest values observed in full-size galaxies.

Bogdan, Akos; Forman, William R.; Kraft, Ralph P.; Jones, Christine; Randall, Scott W.; Li Zhiyuan; Nulsen, Paul E. J.; Vikhlinin, Alexey [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Blom, Christina [Centre for Astrophysics and Supercomputing, Swinburne University, Hawthorn, VIC 3122 (Australia); Zhang Zhongli; Zhuravleva, Irina; Churazov, Eugene [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-str. 1, 85748 Garching (Germany); Schindler, Sabine, E-mail: abogdan@cfa.harvard.edu [Institut fuer Astrophysik, Leopold-Franzens Universitaet Innsbruck, Technikerstrasse 25, 6020 Innsbruck (Austria)

2012-08-10

219

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

SciTech Connect

On a number of occasions The Johns Hopkins University/Applied Physics Laboratory HF radar at Goose Bay, Labrador, has observed the effects of field line resonances on the drift velocities of irregularities in the F region of the high-latitude ionosphere. One of the most interesting sets of resonances occurs near midnight MLT and may be associated with shear in the convective flow in the magnetotail. This paper discusses in detail a particularly clear example which shows field line resonance 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. As expected of field line resonance pulsations, these oscillations had pronounced peaks in their latitudinal power distribution. The pulsations could occur simultaneously but remained distinct as the latitude of peak response was observed to vary inversely with the frequency of the pulsation. The authors interpret these features in terms of field line resonance theory and discuss the possible sources of the pulsation energy.

Ruohoniemi, J.M.; Greenwald, R.A.; Baker, K.B. (Johns Hopkins Univ., Laurel, MD (United States)); Samson, J.C. (Univ. of Alberta, Edmonton (Canada))

1991-09-01

220

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

221

pH-dependent decomposition of. beta. -hydroxy-substituted organophosphorus complexants  

SciTech Connect

Substituted ethane-1,1-diphosphonic acids containing a {beta}-hydroxyl group undergo facile pH-dependent decomposition to phosphoric acid and acetylphosphonate. The decomposition is observed in acidic medium, while the system is stable in basic solutions.

Gatrone, R.C. (Argonne National Lab., IL (USA))

1989-09-01

222

Coupling experimental data and a prototype model to probe the physical and chemical processes of 2,4-dinitroimidazole solid-phase thermal decomposition  

SciTech Connect

The time-dependent, solid-phase thermal decomposition behavior of 2,4-dinitroimidazole (2,4-DNI) has been measured utilizing simultaneous thermogravimetric modulated beam mass spectrometry (STMBMS) methods. The decomposition products consist of gaseous and non-volatile polymeric products. The temporal behavior of the gas formation rates of the identified products indicate that the overall thermal decomposition process is complex. In isothermal experiments with 2,4-DNI in the solid phase, four distinguishing features are observed: (1) elevated rates of gas formation are observed during the early stages of the decomposition, which appear to be correlated to the presence of exogenous water in the sample; (2) this is followed by a period of relatively constant rates of gas formation; (3) next, the rates of gas formation accelerate, characteristic of an autocatalytic reaction; (4) finally, the 2,4-DNI is depleted and gaseous decomposition products continue to evolve at a decreasing rate. A physicochemical and mathematical model of the decomposition of 2,4-DNI has been developed and applied to the experimental results. The first generation of this model is described in this paper. Differences between the first generation of the model and the experimental data collected under different conditions suggest refinements for the next generation of the model.

Behrens, R.; Minier, L. [Sandia National Labs., Livermore, CA (United States). Combustion Research Facility; Bulusu, S. [Army Armament Research, Development and Engineering Center, Dover, NJ (United States). Energetic Materials Div.

1998-12-31

223

Early algorithm development efforts for the National Ecological Observatory Network Airborne Observation Platform imaging spectrometer and waveform lidar instruments  

NASA Astrophysics Data System (ADS)

The National Ecological Observatory Network (NEON) will be the first observatory network of its kind designed to detect and enable forecasting of ecological change at continental scales over multiple decades. NEON will collect data at sites distributed at 20 ecoclimatic domains across the United States on the impacts of climate change, land use change, and invasive species on natural resources and biodiversity. The NEON Airborne Observation Platform (AOP) is an aircraft platform carrying remote sensing instrumentation designed to achieve sub-meter to meter scale ground resolution, bridging the scales from organisms and individual stands to satellite-based remote sensing. AOP instrumentation consists of a VIS/SWIR imaging spectrometer, a scanning small-footprint waveform LiDAR, and a high resolution airborne digital camera. AOP data will provide quantitative information on land use change and changes in ecological structure and chemistry including the presence and effects of invasive species. A Pathfinder Flight Campaign was conducted over a two week period during late August to early September 2010 in order to collect representative AOP data over one NEON domain site. NASA JPL flew the AVIRIS imaging spectrometer and NCALM flew an Optech Gemini waveform LiDAR over the University of Florida Ordway-Swisher Biological Station and Donaldson tree plantation near Gainesville Florida. The pathfinder data are discussed in detail along with how the data are being used for early algorithm and product development prototyping activities. The data collected during the campaign and prototype products are openly available to scientists to become more familiar with representative NEON AOP data.

Krause, Keith S.; Kuester, Michele A.; Johnson, Brian R.; McCorkel, Joel; Kampe, Thomas U.

2011-09-01

224

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

225

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

226

An observation of homogeneous and heterogeneous catalysis processes in the decomposition of H sub 2 O sub 2 over MnO sub 2 and Mn(OH) sub 2  

SciTech Connect

The kinetics of peroxide decomposition by manganese dioxide (MnO{sub 2}) and manganese hydroxide (Mn(OH){sub 2}) have been studied in alkaline solutions. The activity for peroxide decomposition on Mn(OH){sub 2} was generally higher than MnO{sub 2} and the kinetics for the decomposition of H{sub 2}O{sub 2} were first-order in the case of MnO{sub 2} catalysts, but 1.3-order for Mn(OH){sub 2} catalysts. It is suggested that H{sub 2}O{sub 2} is mainly homogeneously decomposed by Mn{sup 2+} ions (in the form of HMnO{sub 2}{sup {minus}} ions in concentrated alkaline solutions) dissolved in the solution in the case of Mn(OH){sub 2}. Compared with the results reported for the decomposition of H{sub 2}O{sub 2} in the presence of 1 ppm Co{sup 2+} ions, it is concluded that the kinetics of the homogeneous decomposition of H{sub 2}O{sub 2} are directly influenced by the concentration of the active species in the solution.

Jiang, S.P.; Ashton, W.R.; Tseung, A.C.C. (Univ. of Essex, Colchester (United Kingdom))

1991-09-01

227

Adiabatic spinodal decomposition in critical binary fluids  

SciTech Connect

We discuss early-stage spinodal decomposition in a near-critical binary fluid for a situation in which the system is quenched abruptly by changing the pressure and in which the subsequent phase separation occurs adiabatically. The resulting nonequilibrium situation has features that do not fit conventional theoretical assumptions. We find that changes in the effective temperature during the transition can account for the lack of agreement between earlier theories and recent experimental results of Bailey and Cannell.

Donley, J.P. (Department of Physics, University of California-Santa Barbara, Santa Barbara, California 93106 (United States)); Langer, J.S. (Institute for Theoretical Physics, University of California-Santa Barbara, Santa Barbara, California 93106 (United States))

1993-09-06

228

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

2013-06-20

229

Thermal decomposition of condensed-phase nitromethane from molecular dynamics from ReaxFF reactive dynamics.  

PubMed

We studied the thermal decomposition and subsequent reaction of the energetic material nitromethane (CH(3)NO(2)) using molecular dynamics with ReaxFF, a first principles-based reactive force field. We characterize the chemistry of liquid and solid nitromethane at high temperatures (2000-3000 K) and density 1.97 g/cm(3) for times up to 200 ps. At T = 3000 K the first reaction in the decomposition of nitromethane is an intermolecular proton transfer leading to CH(3)NOOH and CH(2)NO(2). For lower temperatures (T = 2500 and 2000 K) the first reaction during decomposition is often an isomerization reaction involving the scission of the C-N bond the formation of a C-O bond to form methyl nitrate (CH(3)ONO). Also at very early times we observe intramolecular proton transfer events. The main product of these reactions is H(2)O which starts forming following those initiation steps. The appearance of H(2)O marks the beginning of the exothermic chemistry. Recent quantum-mechanics-based molecular dynamics simulations on the chemical reactions and time scales for decomposition of a crystalline sample heated to T = 3000 K for a few picoseconds are in excellent agreement with our results, providing an important, direct validation of ReaxFF. PMID:21542572

Han, Si-ping; van Duin, Adri C T; Goddard, William A; Strachan, Alejandro

2011-05-04

230

First Stages of the Formation of the South Seasonal Cap in Early Southern Winter as Observed by OMEGA/Mex  

NASA Astrophysics Data System (ADS)

Observations in the visible [1] demonstrated that the retreat of the southern seasonal is very asymmetrical from Ls 230° to Ls 300°, ice extending much further North over a range of longitudes (270° E to 0° E) corresponding to the "bright cap". Observations by TES demonstrated that the bright regions corresponding to the visible cap are at the equilibrium temperature of CO2 ice, as well as the cryptic region, which exhibits low albedos (0.2 - 0.25) close to mid southern spring (Ls 225°). Observations by OMEGA/Mex have Mars Express have demonstrated that the Southern seasonal cap is indeed spectrally dominated by CO2 ice [3, 4]. The low albedo of the cryptic region results from dust contamination on the surface [3] most likely linked to a venting process [5] when CO2 ice sublimates in contact with the underlying surface. OMEGA observed that the very high albedos are linked to large equivalent grain sizes on the bright cap (270°E to 0°E) [4]. These characteristics have been associated with global climate evolution models [6, 7] with a major role played by the two large southern basins, Hellas and Argyre, in the circulation patterns [6]. A possible interpretation of the long lasting cap over the "bright cap" range of longitudes is that the CO2 deposit on the surface is initiated by the sedimentation of small CO2 ice grains or H2O ice grains on the surface followed by the condensation of a layer CO2 directly from the atmosphere. If this is the case, the surface underlying the bright cap regions is protected from photons penetrating the overlying large-grained CO2 layer, which inhibits the venting process, delaying the sublimation of the CO2 ice layer until late spring. Observations by OMEGA close to the southern terminator in early winter (Ls 15°) at high latitudes (70°) obtained in April 2004 and November 2009 correspond to very high incidences (~ 85° or more). This requires a careful evaluation of the aerosol contribution, at the limit of the range of validity of a plane-parallel model [8], and a 3-D model taking into account the curvature of the planet [9]. The first conclusions are that the optical depth of dust is highly variable both spatially and temporally. At longitudes corresponding to the bright cap (e.g. 350° - 0°), the retrieved surface albedos are very high (60% or more), with a spectral signature corresponding to nearly pure, relatively fine-grained CO2 ice (H2O ice content < 10 ppm). High optical depths correspond to very low contrast related to topography. In such regions, the CO2 ice signature is still observed, with a strong blue slope indicating that very fine-grained aerosols (0.5 µm in size or less) are present. OMEGA/Mex observations support the formation of ice grains in the atmosphere before sedimentation early in southern winter, either from homogeneous condensation or from heterogeneous condensation on very fine grained H2O ice. These results support the concept that a thin layer of small CO2 ice grains sedimenting from the atmosphere in early southern winter is at the origin of the long-lasting "bright cap" region of the southern seasonal cap. [1] P. B. James et al. J. Geophys. Res. 84, p. 2889 (1979), [2] H. H. Kieffer et al., J. Geophys. Res. 105, p. 8263 (2000) [3] Y. Langevin et al., Nature 442, p. 831 (2006);[4] Y. Langevin et al., J. Geophys. Res. 112, E08S12 (2007) [5] H. Kieffer, J. Geophys. Res. 112, E08005 (2007); [6] A. Colaprete et al., Nature 435, p. 184 (2005) [7] F. Montmessin et al., J. Geophys. Res. 109, doi: 10.1029/2004JE002284 (2004) [8] M. Vincendon et al., J. Geophys. Res. 112, E08S13 (2007); [9] M. Vincendon and Y. Langevin, Icarus,in press

Langevin, Y.; Vincendon, M.; Bibring, J.-P.; Gondet, B.; Poulet, F.

2010-05-01

231

ChemTeacher: Decomposition Reactions  

NSDL National Science Digital Library

ChemTeacher compiles background information, videos, articles, demonstrations, worksheets and activities for high school teachers to use in their classrooms. The Decomposition Reactions page includes resources for teaching students about identifying and predicting decomposition reactions.

2011-01-01

232

Spinodal Decomposition During Continuous Cooling.  

National Technical Information Service (NTIS)

Spinodal decomposition of a binary solid solution during continuous cooling should lead to a structure that is similar to that resulting from isothermal decomposition, consisting of a superimposition of sinusoidally varying composition modulations cluster...

E. L. Huston J. W. Cahn J. E. Hilliard

1965-01-01

233

Ozone decomposition on walls  

Microsoft Academic Search

In this paper we have estimated the coefficient of ozone decomposition on metallic electrodes (steel, stainless steel and aluminium) in a negative dc corona discharge between a wire and a cylinder in pure oxygen. Using the obtained value of this coefficient and a reduced one-dimensional fluid model, which is described by the continuity and moment transfer equations in the drift

K. Yanallah; S. Hadj Ziane; A. Belasri

2006-01-01

234

Perturbative method for generalized spectral decompositions  

NASA Astrophysics Data System (ADS)

Imposing analytic properties to states and observables we construct a perturbative method to obtain a generalized biorthogonal system of eigenvalues and eigenvectors for quantum unstable systems. A decay process can be described using this generalized spectral decomposition, and the final generalized state is obtained.

Laura, R.

1999-09-01

235

Bit Full-Decomposition of Sequential Machines.  

National Technical Information Service (NTIS)

The report provides the classification of full-decompositions of sequential machines and describes briefly the theoretical foundations of bit full-decomposition. Compared to the symbol full-decomposition, the bit full-decomposition has the following advan...

L. Jozwiak

1989-01-01

236

Variation of Soil Mycoflora in Decomposition of Rice Stubble from Rice-wheat Cropping System  

PubMed Central

The colonization pattern and extent of decay produced in paddy stubble by soil inhabiting mycoflora were done by using nylon net bag technique. Among the three methods used for isolation of fungi, dilution plate technique recorded the highest number of fungi followed by damp chamber and direct observation method. Nutrient availability and climatic conditions (temperature, humidity and rainfall) influenced the occurrence and colonization pattern of fungi. Maximum fungal population was recorded in October (48.99 × 104/g dry litter) and minimum in May (11.41 × 104/g dry litter). Distribution of Deuteromycetous fungi was more in comparison to Zygomycetes, oomycetes and ascomycetes. In the early stage of decomposition Mucor racemosus, Rhizopus nigricans, Chaetomium globosum and Gliocladium species were found primarly whereas at later stages of decomposition preponderance of Aspergillus candidus, Torula graminis, Cladosporiun cladosporioides and Aspergillus luchuensis was recorded.

Sinha, Asha

2007-01-01

237

Variation of Soil Mycoflora in Decomposition of Rice Stubble from Rice-wheat Cropping System.  

PubMed

The colonization pattern and extent of decay produced in paddy stubble by soil inhabiting mycoflora were done by using nylon net bag technique. Among the three methods used for isolation of fungi, dilution plate technique recorded the highest number of fungi followed by damp chamber and direct observation method. Nutrient availability and climatic conditions (temperature, humidity and rainfall) influenced the occurrence and colonization pattern of fungi. Maximum fungal population was recorded in October (48.99 × 10(4)/g dry litter) and minimum in May (11.41 × 10(4)/g dry litter). Distribution of Deuteromycetous fungi was more in comparison to Zygomycetes, oomycetes and ascomycetes. In the early stage of decomposition Mucor racemosus, Rhizopus nigricans, Chaetomium globosum and Gliocladium species were found primarly whereas at later stages of decomposition preponderance of Aspergillus candidus, Torula graminis, Cladosporiun cladosporioides and Aspergillus luchuensis was recorded. PMID:24015096

Vibha; Sinha, Asha

2007-12-31

238

Simultaneous shape decomposition and skeletonization  

Microsoft Academic Search

Shape decomposition and skeletonization share many common properties and applications. However, they are generally treated as independent computations. In this paper, we propose an iterative approach that simul- taneously generates a hierarchical shape decomposition and a corresponding set of multi-resolution skeletons. In our method, a skeleton of a model is extracted from the components of its decomposition | that is,

Jyh-ming Lien; John Keyser; Nancy M. Amato

2006-01-01

239

Approximate convex decomposition of polygons  

Microsoft Academic Search

We propose a strategy to decompose a polygon, containing zero or more holes, into ``approximately convex'' pieces. For many applications, the approximately convex components of this decomposition provide similar benefits as convex components, while the resulting decomposition is significantly smaller and can be computed more efficiently. Moreover, our approximate convex decomposition (ACD) provides a mechanism to focus on key structural

Jyh-Ming Lien; Nancy M. Amato

2004-01-01

240

Color image decomposition and restoration  

Microsoft Academic Search

Meyer has recently introduced an image decomposition model to split an image into two components: a geometrical component and a texture (oscillatory) component. Inspired by his work, numerical models have been developed to carry out the decomposition of gray scale images. In this paper, we propose a decomposition algorithm for color images. We introduce a generaliza- tion of Meyers G

Jean-françois Aujol; Sung Ha Kang

2006-01-01

241

Early Neurological Outcome of Young Infants Exposed to Selective Serotonin Reuptake Inhibitors during Pregnancy: Results from the Observational SMOK Study  

PubMed Central

Background Use of selective serotonin reuptake inhibitors (SSRI) during pregnancy is common while the effect on the infant’s neurological outcome is unknown. Our objective was to determine the effects of prenatal SSRI-exposure on the infants’ neurological functioning, adjusted for maternal mental health. Methods A prospective observational study from May 2007 to April 2010. The study groups comprised 63 SSRI-exposed infants (SSRI group) and 44 non-exposed infants (non-SSRI group). Maternal depression and anxiety were measured using questionnaires. The main outcome measures during the first week after birth and at three to four months were the quality of the infants’ general movements (GMs) according to Prechtl and a detailed motor optimality score. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) for abnormal GM quality in the SSRI and non-SSRI groups, and adjusted for maternal depression, anxiety, and other confounders. The study was registered under 53506435 in the ISRCTN. Findings All infants were born around term. During the first week, abnormal GMs occurred more frequently in the SSRI group than in the non-SSRI group (59% versus 33%) and the median MOS was lower (13 versus 18). The OR for abnormal GMs in the SSRI versus the non-SSRI group was 3·0 (95% CI, 1.3 to 6.9) and increased after adjustment for confounders. At three to four months, more SSRI-exposed infants had monotonous movements (48% versus 20%) with lower median MOSs (26 versus 28). The OR for monotonous movements was 3·5 (95% CI, 1.5 to 8.6) and increased after adjusting for confounders. Interpretation Prenatal exposure to SSRI had an adverse effect on early neurological functioning as reflected by GM quality, irrespective of maternal depression and anxiety, and other confounders. Physicians should take this into account in consultation with parents.

de Vries, Nathalie K. S.; van der Veere, Christine N.; Reijneveld, Sijmen A.; Bos, Arend F.

2013-01-01

242

THE EFFECTS OF REACTOR IRRADIATION UPON THE SUBSEQUENT THERMAL DECOMPOSITION OF LEAD STYPHNATE  

Microsoft Academic Search

The kinetics of the thermal decomposition of lead styphnate were ; examined after being subjected to a series of irradiations in the graphite ; reactor. It was observed that the decomposition rate is enhanced and the ; activation energy for at least part of the decomposition is significantly ; decreased by nuclear irradiation. It also was found that it did

Ted B. Flanagan

1962-01-01

243

Thermal decomposition of tetrabenzyluranium  

SciTech Connect

Thermal decomposition of (PhCH{sub 2}){sub 4}U{center_dot}MgCl{sub 2} has been studied by DTA, TGA methods and also under isothermal conditions at 293-673 K. The decomposition begins at 383 K. Its initial step (383-488 K) involves {alpha}-elimination of hydrogen atom form benzyl radical with the activation energy ca. 60 kJ mole{sup -1} to form toluene and benzylidene compound of uranium. The latter exothermally decomposes at 563 K with uranium-ligand bond cleavage to form mainly dibenzyl, stilbene isomers, and uranium and also products of the secondary ligand transformations: benzene, diphenyl-methane, C{sub 2}-C{sub 4} alkenes, methane, and hydrogen.

Leonov, M.R.; Il`yushenko, V.A.; Kiselev, N.I.

1995-03-01

244

Electromyography interference pattern decomposition.  

PubMed

Decomposition of an interference pattern enables examination of individual electromyography (EMG) motor units and their firing rates at more than minimal contraction forces. In this decomposition method, significant events with a constant occurrence (near motor unit action potentials) can be enhanced, and unwanted events (distant motor unit action potentials, artifacts) eliminated, by calculating the average accumulated change while sliding a fixed-width window along the digitized EMG interference pattern. Nonparametric statistical methods are then applied to these data to determine which information is significant at the .05 level. The exact duration of significant information is identified without the need for arbitrary thresholds and filters to eliminate unwanted information. Events are then classified into groups of similar events by comparing: (1) correlation coefficients, (2) point-to-point differences, (3) amplitudes, and (4) areas. The classification is further refined by the use of firing-rate information. PMID:2059134

Joynt, R L; Erlandson, R F; Wu, S J; Wang, C M

1991-07-01

245

Ceramic decomposition under irradiation  

SciTech Connect

Under this program investigations have been conducted on the physical and chemical processes associated with radiation damage in ceramic materials to understand the mechanisms involved. In addition we have been developing improved methodologies for the analysis of these materials by electron microscopy. The research has clearly shown that the effects of ionization and displacement damage can be distinguished and that processes other than direct displacement and radiolysis contribute to material decomposition.

Howitt, D.G.

1989-01-01

246

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

247

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

248

Decompositional odor analysis database.  

PubMed

This study, conducted at the University of Tennessee's Anthropological Research Facility (ARF), describes the establishment of the Decompositional Odor Analysis (DOA) Database for the purpose of developing a man-portable, chemical sensor capable of detecting clandestine burial sites of human remains, thereby mimicking canine olfaction. This "living" database currently spans the first year and a half of burial, providing identification, chemical trends and semi-quantitation of chemicals liberated below, above and at the surface of graves 1.5 to 3.5 ft deep (0.45 to 1.0 m) for four individuals. Triple sorbent traps (TSTs) were used to collect air samples in the field and revealed eight major classes of chemicals containing 424 specific volatile compounds associated with burial decomposition. This research is the first step toward identification of an "odor signature" unique to human decomposition with projected ramifications on cadaver dog training procedures and in the development of field portable analytical instruments which can be used to locate human remains buried in shallow graves. PMID:15317191

Vass, Arpad A; Smith, Rob R; Thompson, Cyril V; Burnett, Michael N; Wolf, Dennis A; Synstelien, Jennifer A; Dulgerian, Nishan; Eckenrode, Brian A

2004-07-01

249

The C/O ratio at low metallicity: constraints on early chemical evolution from observations of Galactic halo stars  

NASA Astrophysics Data System (ADS)

Aims: We present new measurements of the abundances of carbon and oxygen derived from high-excitation C i and O i absorption lines in metal-poor halo stars, with the aim of clarifying the main sources of these two elements in the early stages of the chemical enrichment of the Galaxy. Methods: We target 15 new stars compared to our previous study, with an emphasis on additional C/O determinations in the crucial metallicity range -3 ? [Fe/H]? -2. The stellar effective temperatures were estimated from the profile of the H? line. Departures from local thermodynamic equilibrium were accounted for in the line formation for both carbon and oxygen. The non-LTE effects are very strong at the lowest metallicities but, contrary to what has sometimes been assumed in the past due to a simplified assessment, of different degrees for the two elements. In addition, for the 28 stars with [Fe/H] < -1 previously analysed, stellar parameters were re-derived and non-LTE corrections applied in the same fashion as for the rest of our sample, giving consistent abundances for 43 halo stars in total. Results: The new observations and non-LTE calculations strengthen previous suggestions of an upturn in C/O towards lower metallicity (particularly for [O/H] ? -2). The C/O values derived for these very metal-poor stars are, however, sensitive to excitation via the still poorly quantified inelastic H collisions. While these do not significantly affect the non-LTE results for C i, they greatly modify the O i outcome. Adopting the H collisional cross-sections estimated from the classical Drawin formula leads to [C/O] ? 0 at [O/H] ? -3. To remove the upturn in C/O, near-LTE formation for O i lines would be required, which could only happen if the H collisional efficiency with the Drawin recipe is underestimated by factors of up to several tens of times, a possibility which we consider unlikely. Conclusions: The high C/O values derived at the lowest metallicities may be revealing the fingerprints of Population III stars or may signal rotationally-aided nucleosynthesis in more normal Population II stars. Based on data collected with the European Southern Observatory's Very Large Telescope (VLT) at the Paranal, Chile (programmes No. 67.D-0106 and 73.D-0024) and with the Magellan Telescope at Las Campanas Observatory, Chile.

Fabbian, D.; Nissen, P. E.; Asplund, M.; Pettini, M.; Akerman, C.

2009-06-01

250

Two-color infrared isotopically selective decomposition of UF6  

Microsoft Academic Search

Isotopically selective unimolecular decomposition of ambient-temperature UFâ has been observed in depletion measurements with an effusive molecular beam irradiated by two 16-..mu..m frequencies produced in a multiple-pass Hâ Raman laser.

P. Rabinowitz; Andrew Kaldor; A. Gnauck; R. L. Woodin; J. S. Gethner

1982-01-01

251

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

252

The creation of a multimedia game computer instruction to encourage observing and classifying skills in science studies for early childhood pupils on “Fun with Science”  

Microsoft Academic Search

This research aimed to create a multimedia computer game instruction to encourage observing and classifying skills in science studies for early childhood pupils on “Fun with Science”. The sampling groups were 35 kindergartners in the third room of the third level from Banklongtan (Krajangjinda) School, in the second semester of academic year 2009. The tools consisted of 1) the multimedia

P. Princhankol; W. Sudsanong; S. Yampinij

2010-01-01

253

Early identification of intensive care unit-acquired infections with daily monitoring of C-reactive protein: a prospective observational study  

Microsoft Academic Search

INTRODUCTION: Manifestations of sepsis are sensitive but are poorly specific of infection. Our aim was to assess the value of daily measurements of C-reactive protein (CRP), temperature and white cell count (WCC) in the early identification of intensive care unit (ICU)-acquired infections. METHODS: We undertook a prospective observational cohort study (14 month). All patients admitted for ?72 hours (n =

Pedro Póvoa; Luís Coelho; Eduardo Almeida; Antero Fernandes; Rui Mealha; Pedro Moreira; Henrique Sabino

2006-01-01

254

The Development of the Problem Decomposition Diagnostic  

NSDL National Science Digital Library

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 subproblems. 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

2007-01-01

255

Nitrosonium-Catalyzed Decomposition of S-Nitrosothiols in Solution  

PubMed Central

The decomposition of S-nitrosothiols (RSNO) in solution under oxidative conditions is significantly faster than can be accounted for by homolysis of the S-N bond. Here we propose a cationic chain mechanism in which nitrosylation of nitrosothiol produces a nitrosylated cation that, in turn, reacts with a second nitrosothiol to produce disulfide and the NO dimer. Nitrosylated dimer acts as a source of nitrosonium for nitrosothiol nitrosylation, completing the catalytic cycle. The mechanism accounts for several unexplained facets of nitrosothiol chemistry in solution, including the observation that the decomposition of an RSNO is accelerated by O2, mixtures of O2 and NO, and other oxidants, that decomposition is inhibited by thiols and other antioxidants, that decomposition is dependent on sulfur substitution, and that decomposition often shows non-integral kinetic orders.

Zhao, Yi-Lei; McCarren, Patrick R.; Houk, K. N.; Choi, Bo Yoon; Toone, Eric J.

2008-01-01

256

Kinetics of spinodal decomposition in a polymer mixture  

NASA Astrophysics Data System (ADS)

The early-to-late stage of spinodal decomposition in a critical mixture of polystyrene and polymethylphenylsiloxane was studied by time-resolved light scattering over 1.8early stage, ?=0.17 in the intermediate stage, and ?=1.08 and ?=0.36 satisfying ?=3? in the late stage. The behavior in the early stage was well expressed by the Cahn-Hillard theory. These exponent values are almost the same as those observed for Fe-Cr alloys. The behavior of the scaled structure factor in the late stage was expressed by a k-6 dependence in km2km, in good agreement with the recent theoretical prediction.

Kuwahara, N.; Sato, H.; Kubota, K.

1993-02-01

257

Spinodal decomposition in Fe-Cr alloys: Experimental study at the atomic level and comparison with computer models. 1: Introduction and methodology  

SciTech Connect

A three-part series of papers is presented concerning the atomic scale analysis of spinodal decomposition in Fe-Cr alloys. This first part deals with the experimental techniques and computer simulations, the second part discusses the dynamics of early stage phase separation, and the third part describes the morphological and structural characterization of spinodal microstructures. In this first paper, three-dimensional reconstructions of the atomic structure of a series of thermally aged Fe-Cr alloys are shown. Two methods for computer simulation of the decomposition process are described. The first is an atomistic simulation based on the Monte Carlo algorithm and the second is a numerical solution to the Cahn-Hilliard-Cook theory. The three-dimensional atomic scale structures resulting from decomposition within the low temperature miscibility gap are reconstructed. It is shown that both models generate microstructures which are qualitatively similar to those observed experimentally.

Miller, M.K. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Division; Hyde, J.M.; Hetherington, M.G.; Cerezo, A.; Smith, G.D.W. [Univ. of Oxford (United Kingdom). Dept. of Materials; Elliott, C.M. [Univ. of Sussex, Brighton (United Kingdom). School of Mathematical and Physical Sciences

1995-09-01

258

Welander's distal myopathy: clinical, neurophysiological and muscle biopsy observations in young and middle aged adults with early symptoms  

Microsoft Academic Search

Nine young or middle aged patients with early symptoms of Welander's distal myopathy were subjected to a detailed neurological examination including quantitative sensory testing, determination of motor and sensory nerve conduction velocity (NCV), sensory nerve action potentials, electromyography (EMG) and muscle biopsy from the tibialis anterior muscle (TA). Slight weakness of the extensors of the fingers and hands was found

K Borg; G Ahlberg; J Borg; L Edström

1991-01-01

259

Two phenotypes and anticipation observed in Japanese cases with early onset torsion dystonia (DYT1) – pathophysiological consideration  

Microsoft Academic Search

Early onset torsion dystonia (DYT1) is a dominantly inherited dystonia caused by a deletion of three bases, GAG, coding glutamic acid, in chromosome 9q34. The protein coded by this gene was named as torsin A. DYT1 is common among the Ashkenazi Jewish population, but has been thought to be rare among Japanese. Among the idiopathic torsion dystonias being followed in

Yoshiko Nomura; Takeshi Ikeuchi; Shoji Tsuji; Masaya Segawa

2000-01-01

260

Environmental effects of solar-thermal power systems: ecological observations during early testing of the Barstow 10-MWe pilot STPS  

Microsoft Academic Search

Environmental measurements were continued at Solar One during 1982, while final steps in construction and early testing were carried out. Measurements of sand depths downwind (east) of the heliostat field indicated that some of the sand blown off the field (most of it between September 1979 and March 1980) has been carried farther east, reducing sand depths somewhat in areas

1982-01-01

261

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

262

Early-career EBD Teacher Knowledge, Ratings of Competency Importance, and Observed Use of Instruction and Management Competencies  

Microsoft Academic Search

The empirical, conceptual, and theoretical knowledge of early-career EBD teachers was assessed two years aer student teaching and compared to their ratings of the importance of specific instruction and classroom management competencies as well as to their application of those competencies. Twelve teachers, six elementary and six secondary, with master's degrees in special education were assessed and three explicit instruction

Lori F. Anderson; Jo Mary. Hendrickson

2007-01-01

263

Direct Observation of Oligomeric Species formed in the Early Stages of Amyloid Fibril Formation using Electrospray Ionisation Mass Spectrometry  

Microsoft Academic Search

Numerous debilitating human disorders result from protein misfolding and amyloid formation. Despite the grave nature of these maladies, our understanding of the structural mechanism of fibril assembly is limited. Of paramount importance is the need to identify and characterize oligomeric species formed early during fibril assembly, so that the nature of the initiating assembly mechanism can be revealed and species

Andrew M. Smith; Thomas R. Jahn; Alison E. Ashcroft; Sheena E. Radford

2006-01-01

264

Sexual Desire During the Menopausal Transition and Early Postmenopause: Observations from the Seattle Midlife Women's Health Study  

PubMed Central

Abstract Aims To describe levels of sexual desire across the menopausal transition (MT) and early postmenopause (PM), including effects of age, MT-related factors, health, stress, symptoms (hot flash, sleep, mood), and social opportunity factors. Methods A subset of Seattle Midlife Women's Health Study (SMWHS) participants who provided data during the early reproductive, early and late menopausal transition stages, or postmenopause (n?=?286), including menstrual calendars for staging the MT, annual health reports between 1990 and 2005, and morning urine samples assayed for estrone glucuronide (E1G), testosterone (T), and follicle-stimulating hormone (FSH) was included. Multilevel modeling using the R program was used to test factors related to sexual desire. Results Women experienced a significant decrease in sexual desire during the late MT stage (p?early PM (p?early morning awakening, and awakening during the night also reported significantly lower sexual desire (p range from <0.03 to 0.0001), but there was no effect of vaginal dryness. Women with better perceived health reported higher sexual desire (p?

Mitchell, Ellen Sullivan; Smith-Di Julio, Kathy

2010-01-01

265

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

266

Multiband photometric decomposition of nuclear stellar disks  

NASA Astrophysics Data System (ADS)

Context. Small, bright stellar disks with scale lengths of a few tens of parsec are known to reside in the center of galaxies. They are believed to have formed in a dissipational process as the end result of star formation in gas either accreted during a merging (or acquisition) event or piled up by the secular evolution of a nuclear bar. Only a few of them have been studied in detail to date. Aims: Using archival Hubble Space Telescope (HST) imaging, we investigate the photometric parameters of the nuclear stellar disks hosted by three early-type galaxies in the Virgo cluster, NGC 4458, NGC 4478, and NGC 4570, to constrain the process that forms their stars. Methods: The central surface brightness, scale length, inclination, and position angle of the nuclear disks were derived by adopting the photometric decomposition method introduced by Scorza & Bender and assuming the disks to be infinitesimally thin and exponential. Results: The location, orientation, and size of the nuclear disks is the same in all the images obtained with the Wide Field Planetary Camera 2 and Advanced Camera for Surveys and available in the HST Science Archive. The scale length, inclination, and position angle of each disk are constant within the errors in the observed U, B, V, and I passbands, independently of their values and the properties of the host spheroid. Conclusions: We interpret the absence of color gradients in the stellar population of the nuclear disks as the signature that star formation homogeneously occurred along their length. An inside-out formation scenario is, instead, expected to produce color gradients and is therefore ruled out.

Morelli, L.; Cesetti, M.; Corsini, E. M.; Pizzella, A.; Dalla Bontà, E.; Sarzi, M.; Bertola, F.

2010-07-01

267

Effects of bacterial dynamics on organic matter decomposition and nutrient release from sediments: A modeling study  

Microsoft Academic Search

Nutrient inputs to lakes, reservoirs, estuaries, and continental shelf waters are often dominated by nutrient release from sediments. Rates of nutrient release from the decomposition of sedimentary organic matter are determined by bacterial demands for food and energy. This dependence of decomposition kinetics on bacterial dynamics, however, is not explicitly considered in current models of early diagenesis. Here, we present

Patrick Schultz; Noel R. Urban

2008-01-01

268

The effect of pressure on the thermal decomposition of nitroalkanes catalyzed by amines  

Microsoft Academic Search

Solutions of 1° and 2° nitroalkanes were thermolyzed in the presence of amines at hydrostatic pressures up to 1.5 GPa, and their rates of decomposition were measured. The probable mechanism of base catalyzed decomposition involves a bimolecular reaction of the aci-nitroalkane with the nitronate ion to yield a carbonyl compound, its corresponding oxime, and nitrite ion as the early rate

Darren L. Naud; Kay R. Brower

1993-01-01

269

A Word of the Empirics: The Ancient Concept of Observation and its Recovery in Early Modern Medicine  

Microsoft Academic Search

The genealogy of observation as a philosophical term goes back to the ancient Greek astronomical and medical traditions, and the revival of the concept in the Renaissance also happened in the astronomical and medical context. This essay focuses primarily on the medical genealogy of the concept of observation. In ancient Greek culture, an elaboration of the concept of observation (t?r?sis)

Gianna Pomata

2011-01-01

270

Low Temperature Decomposition Rates for Tetraphenylborate Ion  

SciTech Connect

Previous studies indicated that palladium is catalyzes rapid decomposition of alkaline tetraphenylborate slurries. Additional evidence suggest that Pd(II) reduces to Pd(0) during catalyst activation. Further use of tetraphenylborate ion in the decontamination of radioactive waste may require removal of the catalyst or cooling to temperatures at which the decomposition reaction proceeds slowly and does not adversely affect processing. Recent tests showed that tetraphenylborate did not react appreciably at 25 degrees Celsius over six months suggesting the potential to avoid the decomposition at low temperatures. The lack of reaction at low temperature could reflect very slow kinetics at the lower temperature, or may indicate a catalyst ''deactivation'' process. Previous tests in the temperature range 35 to 70 degrees Celsius provided a low precision estimate of the activation energy of the reaction with which to predict the rate of reaction at 25 percent Celsius. To understand the observations at 25 degrees Celsius, experiments must separate the catalyst activation step and the subsequent reaction with TPB. Tests described in this report represent an initial attempt to separate the two steps and determine the rate and activation energy of the reaction between active catalyst and TPB. The results of these tests indicate that the absence of reaction at 25 degrees Celsius was caused by failure to activate the catalyst or the presence of a deactivating mechanism. In the presence of activated catalyst, the decomposition reaction rate is significant.

Walker, D.D.

1998-11-18

271

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

Microsoft Academic Search

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

N. Hsiao; T. Shin; Y. Wu

2007-01-01

272

The Early Development of Joint Attention in Infants with Autistic Disorder Using Home Video Observations and Parental Interview  

Microsoft Academic Search

The aim in the current study was to investigate the early development of joint attention, eye contact and affect during the\\u000a first 2 years of life, by using retrospective parental interviews and analyses of home videos of infants who were later diagnosed\\u000a with Autistic Disorder (AD). The 36 children with AD and the 27 matched control children were all aged between

Sally M. Clifford; Cheryl Dissanayake

2008-01-01

273

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

274

Hydrogen iodide decomposition  

SciTech Connect

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/sup 0/ K. and about 525/sup 0/ 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, D.R.; Norman, J.H.

1983-10-18

275

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

276

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

277

A Fantastic Decomposition: Unsettling the Fury of Having to Wait  

ERIC Educational Resources Information Center

|This article draws on data from a single element of a larger project, which focused on the issue of "how children develop a reputation as "naughty" in the early years classroom." The author draws attention to the (in)corporeal (re)formation of the line in school, undertaking a decomposition of the topological spaces of research/art/education. She…

Holmes, Rachel

2012-01-01

278

Spinodal Decomposition in Nickel Based Nickel - Titanium Alloys.  

National Technical Information Service (NTIS)

The early stages of the decomposition process in Ni based Ni-Ti alloys have been studied by means of transmission electron microscopy. It was found that the supersaturated solid solution of Ti in Ni decomposes by the spinodal mechanism into periodic and a...

D. E. Laughlin

1974-01-01

279

Risk factors in critical illness myopathy during the early course of critical illness: a prospective observational study  

PubMed Central

Introduction Non-excitable muscle membrane indicates critical illness myopathy (CIM) during early critical illness. We investigated predisposing risk factors for non-excitable muscle membrane at onset of critical illness. Methods We performed sequential measurements of muscle membrane excitability after direct muscle stimulation (dmCMAP) in 40 intensive care unit (ICU) patients selected upon a simplified acute physiology (SAPS-II) score ? 20 on 3 successive days within 1 week after ICU admission. We then investigated predisposing risk factors, including the insulin-like growth factor (IGF)-system, inflammatory, metabolic and hemodynamic parameters, as well as suspected medical treatment prior to first occurrence of abnormal dmCMAP. Nonparametric analysis of two-factorial longitudinal data and multivariate analysis were used for statistical analysis. Results 22 patients showed abnormal muscle membrane excitability during direct muscle stimulation within 7 (5 to 9.25) days after ICU admission. Significant risk factors for the development of impaired muscle membrane excitability in univariate analysis included inflammation, disease severity, catecholamine and sedation requirements, as well as IGF binding protein-1 (IGFBP-I), but did not include either adjunctive hydrocortisone treatment in septic shock, nor administration of neuromuscular blocking agents or aminoglycosides. In multivariate Cox regression analysis, interleukin-6 remained the significant risk factor for the development of impaired muscle membrane excitability (HR 1.006, 95%-CI (1.002 to 1.011), P = 0.002). Conclusions Systemic inflammation during early critical illness was found to be the main risk factor for development of CIM during early critical illness. Inflammation-induced impairment of growth-factor mediated insulin sensitivity may be involved in the development of CIM.

2010-01-01

280

An Observational Study of the Association of Fluoride Varnish Applied During Well Child Visits and the Prevention of Early Childhood Caries in American Indian Children  

Microsoft Academic Search

Objectives To determine if fluoride varnish applied at well child care visits would decrease the prevalence of dental caries in a group\\u000a of American Indian children at high risk for early childhood caries. Methods This was an observational study in an American Indian community. Starting in 2002 all children received fluoride varnish\\u000a applications at well child care visits at 9,

Steve Holve

2008-01-01

281

Early observed transient prostate-specific antigen elevations on a pilot study of external beam radiation therapy and fractionated MRI guided High Dose Rate brachytherapy boost  

Microsoft Academic Search

PURPOSE: To report early observation of transient PSA elevations on this pilot study of external beam radiation therapy and magnetic resonance imaging (MRI) guided high dose rate (HDR) brachytherapy boost. MATERIALS AND METHODS: Eleven patients with intermediate-risk and high-risk localized prostate cancer received MRI guided HDR brachytherapy (10.5 Gy each fraction) before and after a course of external beam radiotherapy

Anurag K Singh; Peter Guion; Robert C Susil; Deborah E Citrin; Holly Ning; Robert W Miller; Karen Ullman; Sharon Smith; Nancy Sears Crouse; Denise J Godette; Bronwyn R Stall; C Norman Coleman; Kevin Camphausen; Cynthia Ménard

2006-01-01

282

Simultaneous Shape Decomposition and Skeletonization  

Microsoft Academic Search

Shape decomposition and skeletonization share many common properties and applications. However, they are gen- erally treated as independent computations. In this paper, we propose an iterative approach that simultaneously gener- ates a hierarchical shape decomposition and a corresponding set of multi-resolution skeletons. In our method, a skeleton of a model is extracted from the components of its decom- position |

Jyh-Ming Lien; John Keyser; Nancy M. Amato

283

The Thermal Decomposition of Perfluoropropene.  

National Technical Information Service (NTIS)

The thermal decomposition of perfluoropropene in the temperature and initial pressure ranges 550 to 675C and 50 to 200 torr is discussed. The rate of decomposition of perfluoropropene is shown to be first order with respect to the perfluoropropene concent...

R. A. Matula

1968-01-01

284

ATOMIC DECOMPOSITION BY BASIS PURSUIT  

Microsoft Academic Search

The time-frequency and time-scale communities have recently developed a large number of overcomplete waveform dictionaries | stationary wavelets, wavelet packets, cosine packets, chirplets, and warplets, to name a few. Decomposition into overcomplete systems is not unique, and several methods for decomposition have been proposed, including the method of frames (MOF), Matching pursuit (MP), and, for special dictionaries, the best orthogonal

SCOTT SHAOBING; Michael A. Saunders

1998-01-01

285

Decompositions for Optimal Power Flows  

Microsoft Academic Search

This article develops a class of decompositions to break large problems down to sizes the Han-Powell algorithm can comfortably tackle. Although the Han-Powell algorithm is extremely fast for small optimum power flow problems of the order of 100 buses, full size problems of the order of 1000 buses are not as easily handled. The type of decomposition known as the

Sarosh N. Talukdar; Theo C. Giras; Vibhu K. Kalyan

1983-01-01

286

Direct Sum Decomposition of Groups  

ERIC Educational Resources Information Center

|Direct sum decomposition of Abelian groups appears in almost all textbooks on algebra for undergraduate students. This concept plays an important role in group theory. One simple example of this decomposition is obtained by using the kernel and range of a projection map on an Abelian group. The aim in this pedagogical note is to establish a…

Thaheem, A. B.

2005-01-01

287

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

288

Thermal Decomposition of Calcium Superoxide.  

National Technical Information Service (NTIS)

A study has been made of the kinetics of decomposition of calcium superoxide prepared by vacuum decomposition of the compound CaO2.2H2O2. An activation energy for the process equal to 44 kcal/mole has been found. Moreover, there is initially a rise in the...

A. B. Tsentsiper R. P. Vasilyeva

1974-01-01

289

Decomposition of an organophosphonate compound (dimethyl methylphosphonate) on the Ni(111) and Pd(111) surfaces  

SciTech Connect

The decomposition of a model organophosphonate compound, dimethyl methylphosphonate (DMMP), by Pd(111) and Ni(111) surfaces has been studied by using Auger spectroscopy (AES) and temperature-programmed reaction spectroscopy (TPRS). In both cases, in the absence of O{sub 2}, thermal decomposition of DMMP occurs (Pd, below 300 K; Ni, below 340 K) based on the observation of desorption-limited H{sub 2} and CO evolution. Phosphorus is deposited on both Pd(111) and Ni(111) surfaces following the DMMP decomposition. Oxidation at 1,075 K removes the surface phosphorus on Pd(111). On Ni(111), however, surface phosphorus cannot be removed by oxidation at 1,075 K, nor is preoxidized Ni(111) active for phosphorus removal at 1,075 K. By comparison with similar experiments on Mo(110), it appears that the early transition metals may be more suitable for the catalytic oxidation of organophosphonate compounds, on the basis of the lower temperature for sustained removal of surface phosphorus by oxygen on Mo(110) (900 K) compared to Pd(111) (1,075 K).

Guo, X.; Yoshinobu, J.; Yates, J.T. Jr. (Univ. of Pittsburgh, PA (USA))

1990-08-23

290

Polymerization-induced spinodal decomposition of ethylene glycol?phenolic resin solutions under electric fields.  

PubMed

Temporal evolution of polymerization-induced spinodal decomposition (PISD) under electric fields was investigated numerically in ethylene glycol?phenolic resin solutions with different initial composition. A model composed of the nonlinear Cahn-Hilliard-Cook equation for spinodal decomposition and a rate equation for curing reaction was utilized to describe the PISD phenomenon. As initial composition varied, deformed droplet-like and aligned bi-continuous structures were observed in the presence of an electric field. Moreover, the anisotropic parameter (D), determined from the 2D-FFT power spectrum, was employed to quantitatively characterize the degree of morphology anisotropy. The value of D increased quickly in the early stage and then decreased in the intermediate stage of spinodal decomposition, which was attributed to the resistance of coarsening process to morphology deformation and the decline of electric stress caused by polymerization reaction. The results can also provide a guidance on how to control the morphology of monolithic porous polymer and carbon materials with anisotropic structures. PMID:24116581

Zhang, Gang; Qiao, Guanjun

2013-10-01

291

Polymerization-induced spinodal decomposition of ethylene glycol/phenolic resin solutions under electric fields  

NASA Astrophysics Data System (ADS)

Temporal evolution of polymerization-induced spinodal decomposition (PISD) under electric fields was investigated numerically in ethylene glycol/phenolic resin solutions with different initial composition. A model composed of the nonlinear Cahn-Hilliard-Cook equation for spinodal decomposition and a rate equation for curing reaction was utilized to describe the PISD phenomenon. As initial composition varied, deformed droplet-like and aligned bi-continuous structures were observed in the presence of an electric field. Moreover, the anisotropic parameter (D), determined from the 2D-FFT power spectrum, was employed to quantitatively characterize the degree of morphology anisotropy. The value of D increased quickly in the early stage and then decreased in the intermediate stage of spinodal decomposition, which was attributed to the resistance of coarsening process to morphology deformation and the decline of electric stress caused by polymerization reaction. The results can also provide a guidance on how to control the morphology of monolithic porous polymer and carbon materials with anisotropic structures.

Zhang, Gang; Qiao, Guanjun

2013-10-01

292

[Effects of snow cover on the decomposition and nutrient dynamics of Sibiraea angustata leaf litter in western Sichuan plateau, Southwest China].  

PubMed

Soil-borne bag method was adopted to study the decomposition and nutrient dynamics of Sibiraea angustata leaf litter under different depths (0, 30 and 100 cm) of snow cover in western Sichuan plateau in January-May, 2010. In snow-free plot, the mass loss rate of the litter over the five months was 29.9%; in the plots with 30 and 100 cm snow cover, the litter mass loss rate was 33.8% and 35.2%, respectively. During the decomposition, definite N enrichment in the litter was observed, while the P enrichment fluctuated. The C content and C/N ratio of the litter decreased sharply at the early stage of decomposition, but increased gradually after then. Snow cover greatly contributed to the rapid decomposition of litter and the N enrichment in the litter, but had little effects on the litter C and P contents. In western Sichuan plateau, durable snow cover with a depth of > 30 cm could alter the litter decomposition pattern, and substantially affect the soil nutrient turnover and plant community composition. PMID:22919831

Hu, Xia; Wu, Ning; Wu, Yan; Zuo, Wan-Qing; Guo, Hai-Xia; Wang, Jin-Niu

2012-05-01

293

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

294

CWI and FIREBall: Two Spectrographs Built to Observe Emission from the IGM. Instrument Design and Early Results.  

NASA Astrophysics Data System (ADS)

The Cosmic Web Imager (CWI) and the Faint Intergalactic Redshifted Emission Balloon (FIREBall) are two integral field specrographs designed to investigate line emission from the intergalactic medium (predominantly Ly ?, O VI, and CIV). CWI, a ground based instrument, observes in the wavelength interval 4500 to 5400 A, while FIREBall takes advantage of a narrow stratospheric balloon window around 2000 A. The performance and design of the two instruments are discussed. Results of observations of the IGM with these new tools are presented.

Matuszewski, Mateusz; Martin, C.; Morrissey, P.; Moore, A.; CWI Team; FIREBall Team

2012-01-01

295

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

2013-11-29

296

Slewing Mirror Telescope optics for the early observation of UV/optical photons from Gamma-Ray Bursts.  

PubMed

We report on design, manufacture, and testing of a Slewing Mirror Telescope (SMT), the first of its kind and a part of Ultra-Fast Flash Observatory-pathfinder (UFFO-p) for space-based prompt measurement of early UV/optical light curves from Gamma-Ray Bursts (GRBs). Using a fast slewing mirror of 150 mm diameter mounted on a 2 axis gimbal stage, SMT can deliver the images of GRB optical counterparts to the intensified CCD detector within 1.5~1.8 s over ± 35 degrees in the slewing field of view. Its Ritchey-Chrétien telescope of 100 mm diameter provides a 17 × 17 arcmin² instantaneous field of view. Technical details of design, construction, the laboratory performance tests in space environments for this unique SMT are described in conjunction with the plan for in-orbit operation onboard the Lomonosov satellite in 2013. PMID:23389206

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

2013-01-28

297

Decomposition and insect succession on cadavers inside a vehicle environment.  

PubMed

This study presents differences in rate of decomposition and insect succession between exposed carcasses on the soil surface and those enclosed within a vehicle following carbon monoxide (CO) poisoning. Nine 45-kg pigs were used as models for human decomposition. Six animals were sacrificed by CO gas, half of which were placed within the driver's side of separate enclosed vehicles and half were placed under scavenger-proof cages on the soil surface. A further three animals were sacrificed by captive headbolt and placed under scavenger proof cages on the soil surface. The pattern of insect succession and rate of decomposition were similar between surface carcasses within trials regardless of the mode of death. Progression through the physical stages of decomposition was 3-4 days faster in the enclosed vehicle due to higher temperatures there compared to external ambient temperatures. Patterns of insect succession also differed between the vehicle and surface treatments. Carcass attendance by representatives of the Calliphoridae was delayed within the vehicle environment by 16-18 h, while oviposition was not observed until 24-28 h following death. In contrast, attendance by Calliphoridae at surface carcasses occurred within 1 h of death, and oviposition occurred within 6-8 h of death. Typical patterns of insect succession on the carcasses were also altered. Carcass attendance by representatives of the Coleoptera occurred during the bloat stage of decomposition at surface carcasses but was delayed until the onset of wet decomposition (as defined by carcass deflation and breakage of the skin) within the vehicle environment. This study provides baseline data outlining the decomposition patterns of a carcass enclosed within a vehicle following CO poisoning in Western Australia. Understanding how variations in decomposition situations impact on the rate of decomposition and patterns of insect succession is essential to obtaining an accurate estimate of minimum post-mortem interval (PMI). PMID:19291466

Voss, Sasha C; Forbes, Shari L; Dadour, Ian R

2007-08-15

298

Spark decomposition of SF/sub 6/  

SciTech Connect

Gas-insulated systems employing SF/sub 6/ are utilized in a variety of applications in power delivery systems. Because electric arcs, sparks or corona can decompose SF/sub 6/ into by-products having chemical properties different from SF/sub 6/, environmental concerns arise regarding inadvertent human exposures to electrically-decomposed SF/sub 6/. Biological assays in our laboratory using mammalian cell culture systems have revealed that SF/sub 6/, spark-decomposed under specific experimental conditions, can produce cell death. Chemical analysis of spark-decomposed SF/sub 6/ has identified the major decomposition pathways and by-products. Biological testing of individual by-products or by-product mixtures has indicated that these major decomposition products may not account for the majority of the cell killing effects seen in our assays. Further experiments have suggested that S/sub 2/F/sub 10/ may be produced and accumulate under our specific decomposition conditions and that this compound may be a major contributor to the observed cell lethality. On the basis of the biological activity the authors have observed in our spark-decomposed SF/sub 6/ samples, testing of samples from commercial facilities and assays of decomposed gas after ameliorative treatments would both be appropriate investigations.

Griffin, G.D.; Sauers, I.; Kurka, K.; Easterly, C.E.

1989-07-01

299

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

300

Dynamic mode decomposition analysis of detonation waves  

NASA Astrophysics Data System (ADS)

Dynamic mode decomposition is applied to study the self-excited fluctuations supported by transversely unstable detonations. The focus of this study is on the stability of the limit cycle solutions and their response to forcing. Floquet analysis of the unforced conditions reveals that the least stable perturbations are almost subharmonic with ratio between global mode and fundamental frequency ?i/?f = 0.47. This suggests the emergence of period doubling modes as the route to chaos observed in larger systems. The response to forcing is analyzed in terms of the coherency of the four fundamental energy modes: acoustic, entropic, kinetic, and chemical. Results of the modal decomposition suggest that the self-excited oscillations are quite insensitive to vortical forcing, and maintain their coherency up to a forcing turbulent Mach number of 0.3.

Massa, L.; Kumar, R.; Ravindran, P.

2012-06-01

301

Spinodal decomposition in polarized Fermi superfluids  

SciTech Connect

We discuss the dynamics of phase separation through the process of spinodal decomposition in a Fermi superfluid with population imbalance. We discuss this instability first in terms of a phenomenological Landau theory. Working within the mean-field description at zero temperature, we then find the spinodal region in the phase diagram of polarization versus interaction strength and the spectrum of unstable modes in this region. After a quench, the spinodal decomposition starts from the Sarma state, which is a minimum of the free energy with respect to the order parameter at fixed density and polarization and a maximum at fixed chemical potentials. The possibility of observing nontrivial domain structures in current experiments with trapped atomic gases is discussed.

Lamacraft, A. [Department of Physics, University of Virginia, Charlottesville, VA 22904-4714 (United States); Marchetti, F. M. [Rudolf Peierls Centre for Theoretical Physics, 1 Keble Road, Oxford OX1 3NP (United Kingdom)

2008-01-01

302

Decomposition in northern Minnesota peatlands  

SciTech Connect

Decomposition in peatlands was investigated in northern Minnesota. Four sites, an ombrotrophic raised bog, an ombrotrophic perched bog and two groundwater minerotrophic fens, were studied. Decomposition rates of peat and paper were estimated using mass-loss techniques. Environmental and substrate factors that were most likely to be responsible for limiting decomposition were monitored. Laboratory incubation experiments complemented the field work. Mass-loss over one year in one of the bogs, ranged from 11 percent in the upper 10 cm of hummocks to 1 percent at 60 to 100 cm depth in hollows. Regression analysis of the data for that bog predicted no mass-loss below 87 cm. Decomposition estimates on an area basis were 2720 and 6460 km/ha yr for the two bogs; 17,000 and 5900 kg/ha yr for the two fens. Environmental factors found to limit decomposition in these peatlands were reducing/anaerobic conditions below the water table and cool peat temperatures. Substrate factors found to limit decomposition were low pH, high content of resistant organics such as lignin, and shortages of available N and K. Greater groundwater influence was found to favor decomposition through raising the pH and perhaps by introducing limited amounts of dissolved oxygen.

Farrish, K.W.

1985-01-01

303

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

Microsoft Academic Search

On a number of occasions The Johns Hopkins University\\/Applied Physics Laboratory HF radar at Goose Bay, Labrador, has observed the effects of field line resonances on the drift velocities of irregularities in the F region of the high-latitude ionosphere. One of the most interesting sets of resonances occurs near midnight MLT and may be associated with shear in the convective

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

1991-01-01

304

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

305

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

Microsoft Academic Search

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 in kindergarten. Results are also presented in comparison to children's experiences in

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

2009-01-01

306

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

307

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

308

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

309

Early postseismic deformation after the Mw 7.2, October 23, 2011 Van Earthquake (Turkey) Observed by GPS measurements  

NASA Astrophysics Data System (ADS)

On October 23th 2011, a Mw 7.2 earthquake occurred in Van region of eastern Turkey. The earthquake is associated with reverse faulting with a minor left-lateral strike slip component on a NE-SW trending and northward dipping fault. A geodetic network was established one month after the earthquake to monitor the near field postseismic surface deformation. Episodic Global Positioning System (GPS) measurements were performed on this new network in November 2011, January 2012, June 2012 and September 2012. GPS measurements indicate significant postseismic surface motion on the hangingwall of the coseismic fault with southwestward horizontal displacements reaching up to 21 cm, suggesting significant left lateral sense of motion in addition to reverse slip on the main fault. Comparison of coseismic and postseismic GPS measurements reveals aseismic reactivation of a fault segment within the footwall block that splays from the main fault rupture running through the city of Van. GPS time-series up to one year are explained better with a logarithmic function, suggesting that the early postseismic deformation is likely controlled by afterslip. Preliminary elastic modelling of postseismic GPS data using Poly3D suggests that the postseismic deformation is mostly due to oblique (thrust with left-lateral ) afterslip up to ~70 cm at relatively shallow (< 10 km) depths compared to deep (> 15 km) coseismic slip.

Demir, Deniz Oz; Dogan, Ugur; Cakir, Ziyadin; Ergintav, Semih; Ozener, Haluk; Reilinger, Robert

2013-04-01

310

Monte Carlo simulations for spinodal decomposition  

SciTech Connect

This paper addresses the phenomenon of spinodal decomposition for the Cahn-Hilliard equation. Namely, the authors are interested in why most solutions to the Cahn-Hilliard equation which start near a homogeneous equilibrium u{sub 0} {equivalent_to} {mu} in the spinodal interval exhibit phase separation with a characteristic wavelength when exiting a ball of radius R in a Hilbert space centered at u{sub 0}. There are two mathematical explanations for spinodal decomposition, due to Grant and to Maier-Paape and Wanner. In this paper, the authors numerically compare these two mathematical approaches. In fact, they are able to synthesize the understanding they gain from the numerics with the approach of Maier-Paape and Wanner, leading to a better understanding of the underlying mechanism for this behavior. With this new approach, they can explain spinodal decomposition for a longer time and larger radius than either of the previous two approaches. A rigorous mathematical explanation is contained in a separate paper. The approach is to use Monte Carlo simulations to examine the dependence of R, the radius to which spinodal decomposition occurs, as a function of the parameter {var_epsilon} of the governing equation. The authors give a description of the dominating regions on the surface of the ball by estimating certain densities of the distributions of the exit points. They observe, and can show rigorously, that the behavior of most solutions originating near the equilibrium is determined completely by the linearization for an unexpectedly long time. They explain the mechanism for this unexpectedly linear behavior, and show that for some exceptional solutions this cannot be observed. They also describe the dynamics of these exceptional solutions.

Sander, E. [George Mason Univ., Fairfax, VA (United States). Dept. of Mathematical Sciences; Wanner, T. [Univ. of Maryland, Baltimore, MD (United States). Dept. of Mathematics and Statistics

1999-06-01

311

Descent theory for semiorthogonal decompositions  

SciTech Connect

We put forward a method for constructing semiorthogonal decompositions of the derived category of G-equivariant sheaves on a variety X under the assumption that the derived category of sheaves on X admits a semiorthogonal decomposition with components preserved by the action of the group G on X. This method is used to obtain semiorthogonal decompositions of equivariant derived categories for projective bundles and blow-ups with a smooth centre as well as for varieties with a full exceptional collection preserved by the group action. Our main technical tool is descent theory for derived categories. Bibliography: 12 titles.

Elagin, Alexei D

2012-05-31

312

Decomposition and Arthropod Succession in Whitehorse, Yukon Territory, Canada.  

PubMed

Forensic arthropod succession patterns are known to vary between regions. However, the northern habitats of the globe have been largely left unstudied. Three pig carcasses were studied outdoors in Whitehorse, Yukon Territory. Adult and immature insects were collected for identification and comparison. The dominant Diptera and Coleoptera species at all carcasses were Protophormia terraneovae (R-D) (Fam: Calliphoridae) and Thanatophilus lapponicus (Herbst) (Fam: Silphidae), respectively. Rate of decomposition, patterns of Diptera and Coleoptera succession, and species dominance were shown to differ from previous studies in temperate regions, particularly as P. terraenovae showed complete dominance among blowfly species. Rate of decomposition through the first four stages was generally slow, and the last stage of decomposition was not observed at any carcass due to time constraints. It is concluded that biogeoclimatic range has a significant effect on insect presence and rate of decomposition, making it an important factor to consider when calculating a postmortem interval. PMID:23278195

Bygarski, Katherine; Leblanc, Helene N

2012-12-27

313

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

314

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

315

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

2007-06-12

316

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

317

Evidence for Spinodal Decomposition in Nuclear Multifragmentation  

NASA Astrophysics Data System (ADS)

Multifragmentation of a ``fused system'' was observed for central collisions between 32 MeV/nucleon 129Xe and natSn. Most of the resulting charged products were well identified due to the high performances of the INDRA 4? array. Experimental higher-order charge correlations for fragments show a weak but nonambiguous enhancement of events with nearly equal-sized fragments. Supported by dynamical calculations in which spinodal decomposition is simulated, this observed enhancement is interpreted as a ``fossil'' signal of spinodal instabilities in finite nuclear systems.

Borderie, B.; T?b?caru, G.; Chomaz, Ph.; Colonna, M.; Guarnera, A.; Pârlog, M.; Rivet, M. F.; Auger, G.; Bacri, Ch. O.; Bellaize, N.; Bougault, R.; Bouriquet, B.; Brou, R.; Buchet, P.; Chbihi, A.; Colin, J.; Demeyer, A.; Galichet, E.; Gerlic, E.; Guinet, D.; Hudan, S.; Lautesse, P.; Lavaud, F.; Laville, J. L.; Lecolley, J. F.; Leduc, C.; Legrain, R.; Le Neindre, N.; Lopez, O.; Louvel, M.; Maskay, A. M.; Normand, J.; Paw?owski, P.; Rosato, E.; Saint-Laurent, F.; Steckmeyer, J. C.; Tamain, B.; Tassan-Got, L.; Vient, E.; Wieleczko, J. P.

2001-04-01

318

Parallel computing and domain decomposition  

SciTech Connect

Domain decomposition techniques appear a natural way to make good use of parallel computers. In particular, these techniques divide a computation into a local part, which may be done without any interprocessor communication, and a part that involves communication between neighboring and distant processors. This paper discusses some of the issues in designing and implementing a parallel domain decomposition algorithm. A framework for evaluating the cost of parallelism is introduced and applied to answering questions such as which and how many processors should solve global problems and what impact load balancing has on the choice of domain decomposition algorithm. The sources of performance bottlenecks are discussed. This analysis suggests that domain decomposition techniques will be effective on high-performance parallel processors and on networks of workstations. 17 refs., 8 figs.

Gropp, W.

1991-01-01

319

Parallel computing and domain decomposition.  

National Technical Information Service (NTIS)

Domain decomposition techniques appear a natural way to make good use of parallel computers. In particular, these techniques divide a computation into a local part, which may be done without any interprocessor communication, and a part that involves commu...

W. Gropp

1991-01-01

320

Scenario Analysis Via Bundle Decomposition.  

National Technical Information Service (NTIS)

In this paper, we show how the bundle decomposition method can be applied to linear or convex scenario analysis problems that are loosely coupled. We illustrate its effectiveness by presenting computational results for military force planning problems and...

B. J. Chun S. M. Robinson

1995-01-01

321

Meteoric ion layers in the ionospheres of venus and mars: Early observations and consideration of the role of meteor showers  

NASA Astrophysics Data System (ADS)

Layers of metal ions produced by meteoroid ablation have been known in Earth's ionosphere for decades, but have only recently been discovered at Venus and Mars. Here we report the results of a search for meteoric layers in earlier datasets from Venus and Mars. We find 13 candidates at Venus in Mariner 10, Venera 9/10, and Pioneer Venus Orbiter data that augment the 18 previously identified in Venus Express data. We find 8 candidates at Mars in Mariner 7 and Mariner 9 data that augment the 71 and 10 previously identified in Mars Global Surveyor and Mars Express data, respectively. These new findings extend the ranges of conditions under which meteoric layers have been observed, support studies of the temporal variability of meteoric layers, and (for Venus) independently confirm the existence of meteoric layers. One of the proposed causes of temporal variations in the occurrence rate of meteoric layers is meteor showers. This possibility is controversial, since meteor showers have minimal observed effect on meteoric layers in Earth's ionosphere. In order to aid progress towards a resolution of this issue, we present a series of tests for this hypothesis.

Withers, Paul; Christou, A. A.; Vaubaillon, J.

2013-10-01

322

THERMAL DECOMPOSITION OF URANYL NITRATE HEXAHYDRATE  

Microsoft Academic Search

The thermal decomposition of uranyl nitrate hexahydrate was studied in ; the temperature range of 250to 400 deg C at atmospheric and at <0.1 mm pressure. ; The intermediate and final products of the decomposition were determined. The ; decomposition follows a zero-order reaction until less than half of the uranyl ; nitrate remains. The remaining portion of the decomposition

Ondrejcin

1963-01-01

323

Decomposition rates and termite assemblage composition in semiarid Africa  

USGS Publications Warehouse

Outside of the humid tropics, abiotic factors are generally considered the dominant regulators of decomposition, and biotic influences are frequently not considered in predicting decomposition rates. In this study, I examined the effect of termite assemblage composition and abundance on decomposition of wood litter of an indigenous species (Croton megalobotrys) in five terrestrial habitats of the highly seasonal semiarid Okavango Delta region of northern Botswana, to determine whether natural variation in decomposer community composition and abundance influences decomposition rates. 1 conducted the study in two areas, Xudum and Santawani, with the Xudum study preceding the Santawani study. I assessed termite assemblage composition and abundance using a grid of survey baits (rolls of toilet paper) placed on the soil surface and checked 2-4 times/month. I placed a billet (a section of wood litter) next to each survey bait and measured decomposition in a plot by averaging the mass loss of its billets. Decomposition rates varied up to sixfold among plots within the same habitat and locality, despite the fact that these plots experienced the same climate. In addition, billets decomposed significantly faster during the cooler and drier Santawani study, contradicting climate-based predictions. Because termite incidence was generally higher in Santawani plots, termite abundance initially seemed a likely determinant of decomposition in this system. However, no significant effect of termite incidence on billet mass loss rates was observed among the Xudum plots, where decomposition rates remained low even though termite incidence varied considerably. Considering the incidences of fungus-growing termites and non-fungus-growing termites separately resolves this apparent contradiction: in both Santawani and Xudum, only fungus-growing termites play a significant role in decomposition. This result is mirrored in an analysis of the full data set of combined Xudum and Santawani data. The determination that natural variation in the abundance of a single taxonomic group of soil fauna, a termite subfamily, determines almost all observed variation in decomposition rates supports the emerging view that biotic influences may be important in many biomes and that consideration of decomposer community composition and abundance may be critical for accurate prediction of decomposition rates. ?? 2005 by the Ecological Society of America.

Schuurman, G.

2005-01-01

324

Atomic Decomposition by Basis Pursuit  

Microsoft Academic Search

The time-frequency and time-scale communities have recently developed a large number of overcomplete waveform dictionaries—stationary wavelets, wavelet packets, cosine packets, chirplets, and warplets, to name a few. Decomposition into overcomplete systems is not unique, and several methods for decomposition have been proposed, including the method of frames (MOF), matching pursuit (MP), and, for special dictionaries, the best orthogonal basis (BOB).

Scott Shaobing Chen; David L. Donoho

1998-01-01

325

Cadaver decomposition in terrestrial ecosystems  

Microsoft Academic Search

A dead mammal (i.e. cadaver) is a high quality resource (narrow carbon:nitrogen ratio, high water content) that releases an\\u000a intense, localised pulse of carbon and nutrients into the soil upon decomposition. Despite the fact that as much as 5,000 kg\\u000a of cadaver can be introduced to a square kilometre of terrestrial ecosystem each year, cadaver decomposition remains a neglected\\u000a microsere. Here

David O. Carter; David Yellowlees; Mark Tibbett

2007-01-01

326

Geological Observation of the Young Petit-Spot Volcanoes on the Early Cretaceous Pacific Plate using SHINKAI 6500  

NASA Astrophysics Data System (ADS)

Young volcanoes are newly discovered on the cool, thick, and old Pacific Plate approximately 600 km ESE off the northern Japan Trench, during KR04-08 cruise using R/V Kairei (JAMSTEC) in 2004. The site was predicted lava eruption based on previous study for young alkali-basalt lavas (5.95 Ma) on the Japan Trench oceanward slope (the Kaiko knolls lava field). We named the Petit-Spot for such small and young volcanoes. Four SHINKAI 6500 submersible dives (dive #877 to #880) were performed in the Petit-Spot knolls and the Kaiko Knolls lava field during May 2005. Dives were initially targeted in the hopes of finding outcrops of lava flow, sampling rocks, observation of eruptive styles, and discussion of the stratigraphy of the monogenic Petit-Spot volcanoes. Three dives were conducted at the Petit-Spot lava field. One young knoll, named the Yukawa Knoll, discovered by the dredges (D-07, 08) during KR04-08 cruise was selected for dive #877. Two other knolls for dives #878 and #879 show the similar features of bathymetry and acoustic reflectivity to the Yukawa Knoll. In contrast, one site of knoll and fault wall for dive #880 situate in the Kaiko Knolls lava field, the Japan Trench oceanward slope. Dives were planned to ascending the slope from the foot of knoll with continuously observation of lavas and volcaniclastic sequences, and sampling along the slope. The basin or flat floor at the beginning of the dive was fully covered in soft pelagic sediment. We found oblong shaped pillow lavas and the pillow robes outcrops along the slope. However, outcrops are exhibited in limited area around the summit of knoll. Lavas commonly include peperites. Rock fragments sampled appear to be volcanic breccias containing clasts of lava enclosed in sedimentary rock; manganese coating on these breccias is thin, suggesting they were deposited recently. Based on above observation, we assumed that knolls in the Petit-Spot lava field show feeder dike or cryptdome like stratigraphy with some lava flows, in-situ and redeposited hyaloclastites, and water-chilled bumps. That is, basaltic lavas mainly inject into pelagic sediment layer. Furthermore, lavas show very high vesicularity in spite of high water pressure about 6000m deep, suggesting high volatile composition. Brecciated lava clasts containing peridotitic xenolith. These features may indicate that the Petit-Spot volcanoes also have aspect as a kind of abyssal diatreme induced in the oceanic lithosphere.

Machida, S.; Hirano, N.; Ingle, S.; Ishii, T.; Abe, N.

2005-12-01

327

[Decomposition of eucalyptus-alder mixed litters and dynamics of soil faunal community].  

PubMed

In order to understand the decomposition characteristics of eucalyptus (Eucalyptus grandis) -alder (Alnus formosana) mixed litters and the roles of soil fauna in the decomposition process, litter samples of the two tree species were collected from the Suji Town of Leshan, Sichuan Province, and mixed with different proportions. The mixtures were put in 6-, 30-, and 260-mesh litterbags to investigate their mass loss and the dynamics of soil faunal community during the process of decomposition. Different proportion mixtures all presented the same decomposition pattern, i. e., decomposed rapidly in early period and slower in later period. The mixtures had the highest decomposition rate in 6-mesh litterbag, followed by in 30-mesh, and in 260-mesh litterbag. In the litterbags with same meshes, the decomposition rate of different proportion mixed litters also varied. In 6-mesh litterbag, the durations for the decomposition of the litters had slight difference; while in 30- and 260-mesh litterbags, the durations for pure E. grandis and A. formosana litters getting 95% mass loss had a difference of 1175 and 908 days, respectively. During the decomposition of the litters, soil macrofauna had an obvious change in community structure. In early period, Psocoptera dominated; in mid period, Opisthopora dominated; in later period, Coleoptera dominated; and by the end, Diptera dominated. This study provided important information to understand the material cycling in eucalyptus-alder mixed plantation. PMID:21774303

Li, Yan-hong; Luo, Cheng-de; Yang, Wan-qin; Hu, Jie; Wu, Fu-zhong

2011-04-01

328

Nearby Supernova Factory Observations of SN 2006D: On SporadicCarbon Signatures in Early Type Ia Supernova Spectra  

SciTech Connect

We present four spectra of the Type Ia supernova SN Ia 2006Dextending from -7 to +13 days with respect to B-band maximum. The spectrainclude the strongest signature of unburned material at photosphericvelocities observed in a SN Ia to date. The earliest spectrum exhibits CII absorption features below 14,000 km/s, including a distinctive C IIlambda 6580 absorption feature. The carbon signatures dissipate as the SNapproaches peak brightness. In addition to discussing implications ofphotospheric-velocity carbon for white dwarf explosion models, we outlinesome factors that may influence the frequency of its detection before andaround peak brightness. Two effects are explored in this regard,including depopulation of the C II optical levels by non-LTE effects, andline-of-sight effects resulting from a clumpy distribution of unburnedmaterial with low volume-filling factor.

Thomas, R.C.; Aldering, G.; Antilogus, P.; Aragon, C.; Bailey,S.; Baltay, C.; Baron, E.; Bauer, A.; Buton, C.; Bongard, S.; Copin, Y.; Gangler, E.; Gilles, S.; Kessler, R.; Loken, S.; Nugent, P.; Pain, R.; Parrent, J.; Pecontal, E.; Pereira, R.; Perlmutter, S.; Rabinowitz, D.; Rigaudier, G.; Runge, K.; Scalzo, R.; Smadja, G.; Wang, L.; Weaver, B.A.

2006-10-12

329

Unlocking the Power of Observation: Activities to teach early learners the fundamentals of an important inquiry skill  

NSDL National Science Digital Library

The dawn of a new school year is the perfect time to reflect on last year's successes while setting even higher expectations for the upcoming year. For several years, many of our new-school-year resolutions have revolved around a common theme: improving the introduction of inquiry skills to young (kindergarten through second grade) learners, particularly students with limited English-language skills. After experiencing many partial successes, we have found that following easy-to-implement workshop activities to be just what we needed to make our resolutions come true. The activities focus on observation and communication. These skills not only help to focus young children's natural curiosity but also build a solid foundation for future scientific learning.

Martin, Dean M.; Faszewski, Ellen E.; Anderson, Karen L.

2006-09-01

330

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

331

Chandra Observations of the Pleiades Open Cluster: X-Ray Emission from Late B- to Early F-Type Binaries  

NASA Astrophysics Data System (ADS)

We present the analysis of a 38.4 and 23.6 ks observation of the core of the Pleiades open cluster. The Advanced CCD Imaging Spectrometer on board the Chandra X-Ray Observatory detected 99 X-ray sources in a 17'×17' region, including 18 of 23 Pleiades members. Five candidate Pleiades members have also been detected, confirming their cluster membership. Fifty-seven sources have no optical or near-infrared counterparts to limiting magnitudes V=22.5 and J=14.5. The unidentified X-ray sources are probably background active galactic nuclei and not stars. The Chandra field of view contains seven intermediate-mass cluster members. Five of these, HII 980 (B6+G), HII 956 (A7+F6), HII 1284 (A9+K), HII 1338 (F3+F6), and HII 1122 (F4+K), are detected in this study. All but HII 1284 have high X-ray luminosity and soft X-ray spectra. HII 1284 has X-ray properties comparable to nonflaring K-type stars. Since all five stars are visual or spectroscopic binaries with X-ray properties similar to F-G stars, the late-type binary companions are probably producing the observed coronal X-ray emission. Strengthening this conclusion is the nondetection by Chandra of two A stars, HII 1362 (A7, no known companion) and HII 1375 (A0+A SB) with X-ray luminosity upper limits 27-54 times smaller than HII 980 and HII 956, the B6-A7 stars with cooler companions. Despite the low number statistics, the Chandra data appear to confirm the expectation that late B and A stars are not strong intrinsic X-ray sources. The ACIS spectra and hardness ratios suggest a gradual increase in coronal temperature with decreasing mass from F4 to K. M stars appear to have somewhat cooler coronae than active K stars.

Daniel, Kathryne J.; Linsky, Jeffrey L.; Gagné, Marc

2002-10-01

332

Satellite observations of terrestrial water storage provide early warning information about drought and fire season severity in the Amazon  

NASA Astrophysics Data System (ADS)

risk in the Amazon can be predicted several months before the onset of the dry season using sea surface temperatures in the tropical north Atlantic and tropical Pacific. The lead times between ocean state and the period of maximum burning (4-11 months) may enable the development of forecasts with benefits for forest conservation, yet the underlying physical and biological mechanisms responsible for these temporal offsets are not well known. Here, we examined the hypothesis that year-to-year variations in soil water recharge during the wet season modify atmospheric water vapor and fire behavior during the following dry season. We tested this hypothesis by analyzing terrestrial water storage observations from the Gravity Recovery and Climate Experiment (GRACE), active fires from the Moderate Resolution Imaging Spectroradiometer (MODIS), and several other satellite and atmospheric reanalysis datasets during 2002-2011. We found that terrestrial water storage deficits preceded severe fire seasons across the southern Amazon. The most significant relationships between monthly terrestrial water storage and the sum of active fires during the dry season occurred during April-August (p < 0.02), corresponding to 1-5 month lead times before the peak month of burning (September). Analysis of other datasets provided evidence for a cascade of processes during drought events, with lower cumulative precipitation (and higher cumulative evapotranspiration) in the wet season substantially reducing terrestrial water storage, and subsequently, surface and column atmospheric water vapor. Our results suggest that terrestrial water storage observations from GRACE have the potential to improve fire season forecasts for the southern Amazon.

Chen, Yang; Velicogna, Isabella; Famiglietti, James S.; Randerson, James T.

2013-06-01

333

Seasonal necrophagous insect community assembly during vertebrate carrion decomposition.  

PubMed

Necrophagous invertebrates have been documented to be a predominant driver of vertebrate carrion decomposition; however, very little is understood about the assembly of these communities both within and among seasons. The objective of this study was to evaluate the seasonal differences in insect taxa composition, richness, and diversity on carrion over decomposition with the intention that such data will be useful for refining error estimates in forensic entomology. Sus scrofa (L.) carcasses (n = 3-6, depending on season) were placed in a forested habitat near Xenia, OH, during spring, summer, autumn, and winter. Taxon richness varied substantially among seasons but was generally lower (1-2 taxa) during early decomposition and increased (3-8 taxa) through intermediate stages of decomposition. Autumn and winter showed the highest richness during late decomposition. Overall, taxon richness was higher during active decay for all seasons. While invertebrate community composition was generally consistent among seasons, the relative abundance of five taxa significantly differed across seasons, demonstrating different source communities for colonization depending on the time of year. There were significantly distinct necrophagous insect communities for each stage of decomposition, and between summer and autumn and summer and winter, but the communities were similar between autumn and winter. Calliphoridae represented significant indicator taxa for summer and autumn but replaced by Coleoptera during winter. Here we demonstrated substantial variability in necrophagous communities and assembly on carrion over decomposition and among seasons. Recognizing this variation has important consequences for forensic entomology and future efforts to provide error rates for estimates of the postmortem interval using arthropod succession data as evidence during criminal investigations. PMID:23540134

Benbow, M E; Lewis, A J; Tomberlin, J K; Pechal, J L

2013-03-01

334

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

335

Decomposition of chloroethenes in electron beam irradiation  

Microsoft Academic Search

Decomposition of tetrachloroethylene and other chloroethenes in electron beam irradiation were examined in order to get information on treatment of industrial off-gas. The G-values of decomposition were larger in the order of tetrachloro->trichloro->trans-dichloro->cis-dichloro->monochloro-ethylene. For tetrachloroethylene, the effect of initial concentration on G-value of decomposition was also examined. The G-values of decomposition increased with the initial concentration. Decomposition mechanism and the

Teruyuki Hakoda; Guo Zhang; Shoji Hashimoto

1999-01-01

336

Using the Hessenberg decomposition in control theory  

Microsoft Academic Search

Orthogonal matrix techniques are gaining wide acceptance in applied areas by practitioners who appreciate the value of reliable\\u000a numerical software. Quality programs that can be used to compute the QR Decomposition, the Singular Value Decomposition, and\\u000a the Schur Decomposition are primarily responsible for this increased appreciation. A fourth orthogonal matrix decomposition,\\u000a the Hessenberg Decomposition, has recently been put to good

Charles VAN LOAN

337

Decomposition of carrion in the marine environment in British Columbia, Canada  

Microsoft Academic Search

Decomposition of carrion in the marine environment is not well understood. This research involved the decomposition of pig carcasses in Howe Sound in British Columbia. Freshly killed pigs were submerged at two depths, 7.6 m and 15.2 m. The carcasses were tethered so that they could float or sink, but not drift away. Observations were made from May until October. Decomposition was

G. S. Anderson; N. R. Hobischak

2004-01-01

338

Microstructural changes during the decomposition of YBa2Cu4O8 superconductors  

NASA Astrophysics Data System (ADS)

A bulk YBCO-124 specimen produced at 1 atm oxygen pressure via simple solid-state reaction between Y2O3, Ba(NO3)2, and CuO, has been observed during the 940 C decomposition of its 124 phase after undergoing heat treatments for 1.5 min at 850, 875, 910, and finally 940 C. The decomposition products were YBCO-123 phase and CuO. The decomposition process has been characterized by SEM.

Park, Y. K.; Lee, K. W.; Hur, N. H.; Oh, W. K.; Ha, D. H.; Park, K.; Park, J. C.

1991-12-01

339

A spectroscopic study of the thermal decomposition of peroxyacetyl nitrate (PAN)  

Microsoft Academic Search

The thermal decomposition of pure samples of PAN has been monitored at ambient temperature (295 ± 2 K) and pressures of ? 0.5 torr, in a large 6 m cell equipped with White-type multi-pass optics. The minor thermal decomposition products, NO2, HONO and HCHO observed by UV\\/Vis spectroscopic techniques, are consistent with a decomposition mechanism that proceeds via the equilibrium

Gad Fischer; A. U. Nwankwoala

1995-01-01

340

Computer simulation of spinodal decomposition in ternary systems  

SciTech Connect

The non-linear spinodal decomposition kinetics of a quenched homogeneous ternary alloy within three- or two-phase fields is modeled using a computer simulation technique formulated in the reciprocal lattice. Based on two-dimensional computer simulations, it is shown that, similar to binary alloys, spinodal decomposition in a ternary system usually produces interconnected morphologies at the very early stages of decomposition. For most of the compositions investigated, a decomposition of a homogeneous phase into three phases takes place in two stages. For some compositions, the two stages are the phase separation of a homogeneous phase into two phases, followed by further phase separation of one of the two phases into another two phases, resulting in a three-phase mixture. For other compositions, the first stage is a phase separation of an initially homogeneous phase into a two-phase mixture followed by a second stage, the appearance of a third phase along the existing interphase boundaries. This sequential phase separation in a ternary alloy can be justified from a thermodynamic stability analysis combined with the knowledge of the thermodynamic driving force for phase separation. It is also demonstrated that a third minor component strongly segregates to interphase boundaries during spinodal decomposition and subsequent coarsening of a homogeneous ternary alloy into two phases.

Chen, L.Q. (Pennsylvania State Univ., University Park, PA (United States). Dept. of Materials Science and Engineering)

1994-10-01

341

Thermal decomposition of chemisorbed azomethane on Pd(111)  

SciTech Connect

The adsorption and thermal decomposition of azomethane (CH{sub 3}N = NCH{sub 3}) on Pd(111) under ultrahigh-vacuum conditions was studied by temperature-programmed desorption and work function measurements. Adsorbed azomethane is stable on the surface until N-N bond scission occurs at {approx} 250 K. Above 280 K, further decomposition forms H(a) and HCN(a) which subsequently desorb at higher temperatures. No C-N bond dissociation is observed on Pd(111). Thus, both N-N and C-H bond cleavages are observed for chemisorbed azomethane on Pd(111), while only C-N bond cleavage is observed in the gas-phase thermal decomposition of azomethane.

Hanley, L.; Guo, Xingcai; Yates, J.T. Jr. (Univ. of Pittsburgh, PA (USA))

1989-09-07

342

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

343

Fetal nuchal translucency scan and early prenatal diagnosis of chromosomal abnormalities by rapid aneuploidy screening: observational study  

PubMed Central

Objective To investigate an approach for the analysis of samples obtained in screening for trisomy 21 that retains the advantages of quantitative fluorescent polymerase chain reaction (qf-PCR) over full karyotyping and maximises the detection of clinically significant abnormalities. Design Observational study. Setting Tertiary referral centre. Subjects 17 446 pregnancies, from which chorionic villous samples had been taken after assessment of risk for trisomy 21 by measurement of fetal nuchal translucency (NT) thickness at 11 to 13+6 weeks of gestation. Interventions Analysis of chorionic villous samples by full karyotyping and by qf-PCR for chromosomes 13, 18, 21, X, and Y. Main outcome measure Detection of clinically significant chromosomal abnormalities. Results The fetal karyotype was normal in 15 548 (89.1%) cases and abnormal in 1898 (10.9%) cases, including 1722 with a likely clinically significant adverse outcome. Karyotyping all cases would lead to the diagnosis of all clinically significant abnormalities, and a policy of relying entirely on qf-PCR would lead to the diagnosis of 97.9% of abnormalities. An alternative strategy whereby qf-PCR is the main method of analysis and full karyotyping is reserved for those cases with a minimum fetal NT thickness of 4 mm would require full karyotyping in 10.1% of the cases, would identify 99.0% of the significant abnormalities, and would cost 60% less than full karyotyping for all. Conclusions In the diagnosis of chromosomal abnormalities after first trimester screening for trisomy 21, a policy of qf-PCR for all samples and karyotyping only if the fetal NT thickness is increased would reduce the economic costs, provide rapid delivery of results, and identify 99% of the clinically significant chromosomal abnormalities.

Chitty, Lyn S; Kagan, Karl O; Molina, Francisca S; Waters, Jonathan J; Nicolaides, Kypros H

2006-01-01

344

Effects observed in the Latin American sector ionospheric F region 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 this paper, we have investigated the generation and suppression of equatorial ionospheric irregularities and the daytime changes in the F region electron density in the Latin American sector during the period of intense geomagnetic disturbances. We present the ionospheric sounding observations carried out at Manaus and Sao Jose dos Campos, Brazil, during this geomagnetically disturbed period. Also, GPS observations obtained from several stations in Brazil, Argentina, and St. Croix, U.S. Virgin Islands, during the disturbed period are presented. During the main phase of the first superstorm, around the prereversal enhancement time (night of 7-8 November), prompt penetration of electric field was observed and the presence of equatorial ionospheric irregularities was detected from St. Croix, U.S. Virgin Islands (in the northern hemisphere) to Bahia Blanca, Argentina (in the southern hemisphere). The ionospheric sounding observations at Manaus indicate inhibition of prereversal enhancement on the nights of 9-10 and 10-11 November, possibly due to the disturbed thermospheric winds or disturbance electric fields. Virtually no phase fluctuations on the nights of 9-10 and 10-11 November were observed in the Latin American sector. During the daytime on 8 November, the vertical total electron content (VTEC) observations show a negative storm phase at Porto Alegre (Brazil) and Bahia Blanca (Argentina). Again during the daytime on 10 November, the VTEC observations show a negative storm phase from Brasilia (Brazil) to Bahia Blanca. These negative storm phases are associated with a decrease in the O/N2 ratio. During the daytime on 9 November, the VTEC observations show a positive storm phase extending from St. Croix to Porto Alegre, and again on 10 November, VTEC observations show a positive storm phase. These positive storm phases observed are possibly due to changes in large-scale wind circulation and an increase in the O/N2 ratio.

Sahai, Y.; Becker-Guedes, F.; Fagundes, P. R.; de Jesus, R.; de Abreu, A. J.; Paxton, L. J.; Goncharenko, L. P.; Brunini, C.; Gende, M.; Ferreira, A. S.; Lima, N. S.; Guarnieri, F. L.; Pillat, V. G.; Bittencourt, J. A.; Candido, C. M. N.

2009-03-01

345

BIODIVERSITY AND LITTER DECOMPOSITION IN TERRESTRIAL ECOSYSTEMS  

Microsoft Academic Search

? Abstract We explore empirical and theoretical evidence,for the functional sig- nificance of plant-litter diversity and the extraordinary,high diversity of decomposer organisms,in the process of litter decomposition,and the consequences,for biogeochem- ical cycles. Potential mechanisms,for the frequently observed,litter-diversity effects on mass,loss and nitrogen dynamics,include fungi-driven nutrient transfer among,litter species, inhibition or stimulation of microorganisms by specific litter compounds, and positive feedback,of

Stephan Hattenschwiler; Alexei V. Tiunov; Stefan Scheu

2005-01-01

346

Mechanism of the Thermal Decomposition of Furan  

NASA Astrophysics Data System (ADS)

Both furan (C_4H_4O) and furfural (C_4H_3O-CHO) areimportant products in biomass pyrolysis. We have used a resistively-heated SiC tubular reactor with a 30 microseconds residence time to study the thermal cracking of furan. The decomposition products are identified by two independent techniques: 118.2 nm VUV photoionization mass spectroscopy and infrared spectroscopy. We observe three different thermal dissociation channels leading to: a) CH_3CCH + CO b) HCCH + CH_2CO c) HCCCH_2.

Vasiliou, Angayle; Ellison, G. Barney; Nimlos, Mark R.; Daily, John W.

2009-06-01

347

Thermal decomposition as route for silver nanoparticles  

NASA Astrophysics Data System (ADS)

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.; Viswanathan, B.; Viswanath, R. P.; Varadarajan, T. K.

2007-01-01

348

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

2011-04-21

349

Amorphous precursors of crystallization during spinodal decomposition.  

PubMed

A general Landau's free energy functional is used to study the dynamics of crystallization during liquid-solid spinodal decomposition (SD). The strong length scale selectivity imposed during the early stage of SD induces the appearance of small precursors for crystallization with icosahedral order. These precursors grow in densely packed clusters of tetrahedra through the addition of new particles. As the average size of the amorphous nuclei becomes large enough to reduce geometric frustration, crystalline particles with a body-centered cubic symmetry heterogeneously nucleate on the growing clusters. The volume fraction of the crystalline phase is strongly dependent on the depth of quench. At deep quenches, the SD mechanism produces amorphous structures arranged in dense polytetrahedral aggregates. PMID:21405846

Gómez, Leopoldo R; Vega, Daniel A

2011-02-10

350

Decomposition in Arctic terrestrial environments  

SciTech Connect

The principal goal of this research unit is to further elucidate the rate and quality of microbial decomposition within cold, wet, Arctic tundra peat soils found in water tract systems of Foothills Province terrain (8-10{degree}) on the north slope of Alaska. Research objectives include demonstration of of four hypotheses. A positive correlation exists between the rate of decomposing litter and the viable microbial (fungal) biomass, as measured by ARP activities and direct counts, associated with that litter. In Arctic tundra peat soil systems, there exists a positive correlation between the presence and abundance of viable mycelial biomass and the enzymatic potential for degradative activity as measured by the presence of cellulase, peroxidase, chitinase and protease enzymes produced by the miocrobial community. Substrate quality, as defined by lignin to cellulose ratios, influences the rate of natural litter decomposition. The lignin to total nitrogen ratio describes an inverse correlation to decomposition rates of litter.

Laursen, G.A.

1989-01-01

351

Decomposition of 14C containing organic molecules released from radioactive waste by gamma-radiolysis under repository conditions  

NASA Astrophysics Data System (ADS)

Decomposition of 14C containing organic molecules into an inorganic compound has been investigated by ?-ray irradiation experiments under simulated repository conditions for radioactive waste. Lower molecular weight organic acids, alcohols, and aldehydes leached from metallic waste are reacted with OH radicals to give carbonic acid. A decomposition efficiency that expresses consumption of OH radicals by decomposition reaction of organic molecules is proposed. Decomposition efficiency increases with increasing concentration of organic molecules (1×10-6-1×10-3 mol dm-3) and is not dependent on dose rate (10-1000 Gy h-1). Observed dependence indicates that decomposition efficiency is determined by reaction probability of OH radicals with organic molecules.

Kani, Yuko; Noshita, Kenji; Kawasaki, Toru; Nasu, Yuji; Nishimura, Tsutomu; Sakuragi, Tomofumi; Asano, Hidekazu

2008-04-01

352

Kinetics of spinodal decomposition in a polymer mixture  

Microsoft Academic Search

The early-to-late stage of spinodal decomposition in a critical mixture of polystyrene and polymethylphenylsiloxane was studied by time-resolved light scattering over 1.8

N. Kuwahara; H. Sato; K. Kubota

1993-01-01

353

Lattice Boltzmann study of spinodal decomposition in two dimensions  

Microsoft Academic Search

A lattice Boltzmann model using the Shan-Chen prescription for a binary immiscible fluid is described, and the macroscopic equations obeyed by the model are derived. The model is used to quantitatively examine spinodal decomposition of a two-dimensional binary fluid. This model allows examination of the early-time period corresponding to interface formation, and shows agreement with analytical solutions of the linearized

Jonathan Chin; Peter V. Coveney

2002-01-01

354

Nucleon Momentum and Spin Decompositions  

SciTech Connect

We construct a gauge invariant canonical momentum operator which satisfies the canonical commutation relation to resolve the old controversy on the canonical versus kinematic momentum of a charged particle in gauge theories. With this we show how to obtain the gauge independent momentum and spin decompositions of composite particles to those of the constituents in QED and QCD, which has been thought to be impossible. Moerover, we show that there are two logically acceptable nucleom momentum and spin decompositions, depending on which gluons we identify as the constituent of nucleons.

Cho, Y. M. [School of Electrical and Computer Engineering, Ulsan National Institute of Science and Technology, Ulsan 689-798 (Korea, Republic of) and School of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of)

2011-12-14

355

A study of powder making by the decomposition of nickel carbonyl in an aerosol tube reactor  

Microsoft Academic Search

In this study, nickel carbonyl decomposition in a hot wall tube reactor was investigated using mathematical modeling and experimental observations. A simple first principles approach was used to develop a model for particle growth inside the reactor. The mass balance was composed from published mechanisms and constants for the simultaneous homogeneous and heterogeneous decomposition of nickel carbonyl. The particle population

Eric Bain Wasmund

2005-01-01

356

Discovery and preliminary confirmation of novel early detection biomarkers for triple-negative breast cancer using preclinical plasma samples from the Women's Health Initiative observational study  

PubMed Central

Triple-negative breast cancer is a particularly aggressive and lethal breast cancer subtype that is more likely to be interval-detected rather than screen-detected. The purpose of this study is to discover and initially validate novel early detection biomarkers for triple-negative breast cancer using preclinical samples. Plasma samples collected up to 17 months prior to diagnosis from 28 triple-negative cases and 28 matched controls from the Women’s Health Initiative Observational Study were equally divided into a training set and a test set and interrogated using a customized antibody array. Data were available on 889 antibodies, and in the training set statistically significant differences in case vs. control signals were observed for 93 (10.5%) antibodies at p<0.05. Of these 93 candidates, 29 were confirmed in the test set at p<0.05. Areas under the curve for these candidates ranged from 0.58 to 0.79. With specificity set at 98%, sensitivity ranged from 4% to 68% with ?20 candidates having a sensitivity 20% and 6 having a sensitivity ?40%. In an analysis of KEGG gene sets, the pyrimidine metabolism gene set was upregulated in cases compared to controls (p=0.004 in the testing set) and the JAK/Stat signaling pathway gene set was downregulated (p=0.003 in the testing set). Numerous potential early detection biomarkers specific to triple-negative breast cancer in multiple pathways were identified. Further research is required to follow-up on promising candidates in larger sample sizes and to better understand their potential biological importance as our understanding of the etiology of triple-negative breast cancer continues to grow.

Li, Christopher I.; Mirus, Justin E.; Zhang, Yuzheng; Ramirez, Arturo B.; Ladd, Jon J.; Prentice, Ross L.; McIntosh, Martin; Hanash, Samir M.; Lampe, Paul D.

2012-01-01

357

Moessbauer spectroscopy evidence of a spinodal mechanism for the thermal decomposition of fcc FeCu  

SciTech Connect

Moessbauer spectroscopy shows the existence of compositional fluctuations, where different Fe environments coexist, during decomposition upon heat treatment of metastable f.c.c. FeCu solid solution. The presence of isolated Fe atoms in the Cu matrix, f.c.c. Fe{sub rich}Cu, f.c.c. FeCu{sub rich} and b.c.c. Fe has been detected in early decomposition stages. At later decomposition stages, low temperature Moessbauer spectroscopy indicates the presence of a broad distribution of Curie temperatures, coexisting with isolated Fe atoms in the Cu matrix, f.c.c. Fe and b.c.c. Fe.

Crespo, P. [IMA, Madrid (Spain)]|[CENIM-CSIC, Madrid (Spain); Barro, M.J.; Hernando, A. [IMA, Madrid (Spain); Escorial, A.G. [CENIM-CSIC, Madrid (Spain); Menendez, N.; Tornero, J.D. [UAM, Madrid (Spain). Dpto. Quimica-Fisica Aplicada; Barandiaran, J.M. [Univ. del Pais Vasco, Bilbao (Spain)

1998-07-24

358

Influence of non-cellulose structural carbohydrate composition on plant material decomposition in soil  

Microsoft Academic Search

The C mineralisation pattern during the early stage of decomposition of plant materials is largely determined by their content\\u000a of different carbohydrates. This study investigated whether detailed plant analysis could provide a better prediction of C\\u000a mineralisation during decomposition than proximate analysis [neutral detergent solution (NDF)\\/acid detergent solution (ADF)].\\u000a The detailed analysis included sugars, fructans, starch, pectin, cellulose, lignin and

Sophie Gunnarsson; Håkan Marstorp; A Sigrun Dahlin; Ernst Witter

2008-01-01

359

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

360

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 emissions 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 unsuccessful. 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.

KHALID ALMUSAITEER; RAM KRISHNAMURTHY; STEVEN S.C. CHUANG

1998-08-18

361

Decomposition of Aluminosilicates by Soil Bacteria.  

National Technical Information Service (NTIS)

The formation of many types of soils is accompanied by decomposition of aluminosilicates including feldspars and kaolinites. Such decomposition if usually attributed to the effect of acid soil solutions, even though the experimental data failed to yield a...

L. E. Novorossova N. P. Remezov N. N. Sushkina

1968-01-01

362

Leaf Decomposition in a Tropical Rainforest Stream.  

National Technical Information Service (NTIS)

Fungi play an important part in leaf litter decomposition in terrestrial ecosystems in both temperate and tropical regions. There are few published reports dealing with decomposition in running waters, and no work has been done in tropical streams. Result...

D. E. Padgett

1975-01-01

363

Synthesis of Automata by Decomposition Techniques.  

National Technical Information Service (NTIS)

The major effort under this research program was devoted to parallel decompositions of single-input automata (autonomous sequential machines) without and with state-splitting. First, decompositions into two smaller automata subject to suitable optimality ...

C. M. Ablow M. Yoeli

1966-01-01

364

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

365

Algebraic cell decomposition in NC  

Microsoft Academic Search

We give an algorithm to construct a cell decomposition of Rd, including adjacency information, defined by any given set of rational polynomials in d variables. The algorithm runs in single exponential parallel time, and in NC for fixed d. The algorithm extends a recent algorithm of Ben-Or, Kozen, and Reif for deciding the theory of real closed fields.

Dexter KozenI; Chee-Kang Yap

1985-01-01

366

Hierarchical Decomposition of Multiscale Skeletons  

Microsoft Academic Search

The paper presents a novel procedure to hierarchically decompose a multiscale discrete skeleton. The skeleton is a linear pattern representation that is generally recognized as a good shape descriptor. For discrete images, the discrete skeleton is often preferable. Multiresolution representations are convenient for many image analysis tasks. Our resulting skeleton decomposition shows two different types of hierarchy. The first type

Gunilla Borgefors; Giuliana Ramella; Gabriella Sanniti Di Baja

2001-01-01

367

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

368

Mechanism of Nitrous Acid Decomposition.  

National Technical Information Service (NTIS)

The mechanism of nitrous acid decomposition was studied. It was concluded that the reaction 2HNO sub 2 implies NO + NO sub 2 + H sub 2 O took place at the gas-liquid interface. The rate of the reaction was found to be determined by the diffusion of nitrou...

H. Kobayashi K. Hara K. Kitano N. Takezawa T. Nikki

1976-01-01

369

The ecology of carrion decomposition  

Technology Transfer Automated Retrieval System (TEKTRAN)

Carrion, or the remains of dead animals, is something that most people would like to avoid. It is visually unpleasant, emits foul odors, and may be the source of numerous pathogens. Decomposition of carrion, however, provides a unique opportunity for scientists to investigate how nutrients cycle t...

370

Cadaver decomposition in terrestrial ecosystems  

NASA Astrophysics Data System (ADS)

A dead mammal (i.e. cadaver) is a high quality resource (narrow carbon:nitrogen ratio, high water content) that releases an intense, localised pulse of carbon and nutrients into the soil upon decomposition. Despite the fact that as much as 5,000 kg of cadaver can be introduced to a square kilometre of terrestrial ecosystem each year, cadaver decomposition remains a neglected microsere. Here we review the processes associated with the introduction of cadaver-derived carbon and nutrients into soil from forensic and ecological settings to show that cadaver decomposition can have a greater, albeit localised, effect on belowground ecology than plant and faecal resources. Cadaveric materials are rapidly introduced to belowground floral and faunal communities, which results in the formation of a highly concentrated island of fertility, or cadaver decomposition island (CDI). CDIs are associated with increased soil microbial biomass, microbial activity (C mineralisation) and nematode abundance. Each CDI is an ephemeral natural disturbance that, in addition to releasing energy and nutrients to the wider ecosystem, acts as a hub by receiving these materials in the form of dead insects, exuvia and puparia, faecal matter (from scavengers, grazers and predators) and feathers (from avian scavengers and predators). As such, CDIs contribute to landscape heterogeneity. Furthermore, CDIs are a specialised habitat for a number of flies, beetles and pioneer vegetation, which enhances biodiversity in terrestrial ecosystems.

Carter, David O.; Yellowlees, David; Tibbett, Mark

2007-01-01

371

Spectral decomposition of anisotropic elasticity  

Microsoft Academic Search

Summary A newly developed approach, based on the spectral decomposition principle, which is especially useful in crystallography, is applied in this paper. The compliance fourth-rank tensor of crystalline media belonging to the monoclinic system is spectrally decomposed, its eigenvalues are evaluated, together which its elementary idempotent tensors, which expand uniquely the fourth-rank tensor space into orthogonal subspaces. Next, the compliance

P. S. Theocaris; D. P. Sokolis

2001-01-01

372

Relation between chemical and electrochemical steps in the anodic decomposition of III-V semiconductor electrodes: A comprehensive model  

SciTech Connect

An overview is given of the different mechanisms of anodic decomposition, observed at GaAs and GaP electrodes. A comprehensive model is proposed, in which a chemical reaction between a mobile surface intermediate and water molecules is crucial for the competition between different electrochemical decomposition steps. The model accounts for the changes in decomposition mechanism observed when varying the activity of water or of protons and the anodic current density.

Vanmaekelbergh, D. (Univ. of Utrecht (Netherlands)); Gomes, W.P. (Rijksuniversiteit Gent (Belgium))

1990-02-22

373

Purine loading, stem-loops and Chargaff's second parity rule: a discussion of the application of elementary principles to early chemical observations.  

PubMed

DNA base compositions were determined chemically long before sequencing technologies permitted the direct counting of bases. Some recent observations made using modern sequencing technologies could have been deduced by application of elementary principles to early chemical observations. This paper draws attention to the fact that the potential for significant stem-loop structure is a general property of single-stranded DNA (genic and non-genic) and hence for any corresponding transcripts, whether they function by virtue of their structure (eg rRNA) or as mRNA. Furthermore, there is Chargaff's second parity rule: in single strands, the percentage of purines approximately equals the percentage of pyrimidines. Since, in stems, purines match pyrimidines, Szybalski's rule that transcripts violate the second parity rule in favour of purines, must apply to loops. Since purine loading occurs in both mesophilic and thermophilic species, genes with transcripts that need stable secondary structures for functioning at high temperatures must achieve this by selectively increasing the GC percentage (GC%) of stems, while retaining purine loading of loops. Arguments that purine loading is specific for the loops of RNA-synonymous strands of genes whose transcripts function by virtue of their secondary structure (ie rRNAs, not mRNAs) need to take into account, as controls, the loop regions of mRNA-synonymous strands. Entire genes, or entire genomes where gene orientation is not considered, are not appropriate controls. PMID:16323961

Forsdyke, Donald R; Bell, Sheldon J

2004-01-01

374

Hydrodynamic spinodal decomposition: Growth kinetics and scaling functions  

SciTech Connect

We examine the effects of hydrodynamics on the late-stage kinetics in spinodal decomposition. From computer simulations of a lattice Boltzmann scheme we observe, for critical quenches, that single-phase domains grow asymptotically like [ital t][sup [alpha

Alexander, F.J.; Chen, S.; Grunau, D.W. (Center for Nonlinear Studies and Theoretical Division and Earth Environmental Sciences, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States))

1993-07-01

375

Hydrodynamic spinodal decomposition: Growth kinetics and scaling functions  

Microsoft Academic Search

We examine the effects of hydrodynamics on the late-stage kinetics in spinodal decomposition. From computer simulations of a lattice Boltzmann scheme we observe, for critical quenches, that single-phase domains grow asymptotically like [ital t][sup [alpha

F. J. Alexander; S. Chen; D. W. Grunau

1993-01-01

376

Spinodal decomposition in particle-laden Landau-Levich flow  

NASA Astrophysics Data System (ADS)

We examine Landau-Levich coating by a suspension of spherical particles. For particles larger than the liquid film thickness, capillary forces lead to self-assembly of monolayer particle aggregates. We observe two regimes of deposition, find coating fraction as a function of wall speed, and propose a spinodal decomposition (Cahn-Hilliard) model for this pattern formation process.

Kao, Justin C. T.; Hosoi, A. E.

2012-04-01

377

Pressure-induced decomposition of indium hydroxide.  

PubMed

A static pressure-induced decomposition of indium hydroxide into metallic indium that takes place at ambient temperature is reported. The lattice parameter of c-In(OH)(3) decreased upon compression from 7.977(2) to approximately 7.45 A at 34 GPa, corresponding to a decrease in specific volume of approximately 18%. Fitting the second-order Birch-Murnaghan equation of state to the obtained compression data gave a bulk modulus of 99 +/- 3 GPa for c-In(OH)(3). The c-In(OH)(3) crystals with a size of approximately 100 nm are comminuted upon compression, as indicated by the grain-size reduction reflected in broadening of the diffraction reflections and the appearance of smaller (approximately 5 nm) incoherently oriented domains in TEM. The rapid decompression of compressed c-In(OH)(3) leads to partial decomposition of indium hydroxide into metallic indium, mainly as a result of localized stress gradients caused by relaxation of the highly disordered indium sublattice in indium hydroxide. This partial decomposition of indium hydroxide into metallic indium is irreversible, as confirmed by angle-dispersive X-ray diffraction, transmission electron microscopy imaging, Raman scattering, and FTIR spectroscopy. Recovered c-In(OH)(3) samples become completely black and nontransparent and show typical features of metals, i.e., a falling absorption in the 100-250 cm(-1) region accompanied by a featureless spectrum in the 250-2500 cm(-1) region in the Raman spectrum and Drude-like absorption of free electrons in the region of 4000-8000 cm(-1) in the FTIR spectrum. These features were not observed in the initial c-In(OH)(3), which is a typical white wide-band-gap semiconductor. PMID:20731389

Gurlo, Aleksander; Dzivenko, Dmytro; Andrade, Miria; Riedel, Ralf; Lauterbach, Stefan; Kleebe, Hans-Joachim

2010-09-15

378

Biogeochemistry of Decomposition and Detrital Processing  

Microsoft Academic Search

Decomposition is a key ecological process that roughly balances net primary production in terrestrial ecosystems and is an essential process in resupplying nutrients to the plant community. Decomposition consists of three concurrent processes: communition or fragmentation, leaching of water-soluble compounds, and microbial catabolism. Decomposition can also be viewed as a sequential process, what Eijsackers and Zehnder (1990) compare to a

J. Sanderman; R. Amundson

2003-01-01

379

Digraph Decompositions and Monotonicity in Digraph Searching  

Microsoft Academic Search

We consider Cops and Robber games on digraphs and their corresponding decompositions. In particular we show non-monotonicity of two important variants of these games, namely the variants underlying DAG- and Kelly-decompositions. Furthermore we explore the limits of the algorithmic applicability of digraph decompositions and show that various natural candidates for problems that might benefit from digraphs having small \\

Stephan Kreutzer; Sebastian Ordyniak

2008-01-01

380

Kinetic modeling of Pt-catalyzed glycolaldehyde decomposition to syngas.  

PubMed

Fundamental knowledge of the elementary reaction mechanisms involved in oxygenate decomposition on transition metal catalysts can facilitate the optimization of future catalyst and reactor systems for biomass upgrade to fuels and chemicals. Pt-catalyzed decomposition of glycolaldehyde, as the smallest oxygenate with alcohol and aldehyde functionality, was studied via a DFT-based microkinetic model. It was found that two decomposition pathways exist. Under conditions of low hydrogen surface coverage, the initial C-H bond breaking reaction to HOCH(2)CO* is prevalent, while under conditions of high hydrogen coverage, the rather unexpected O-H bond forming reaction to HOCH(2)CHOH* is more active (subsequent decomposition is energetically favorable from HOCH(2)CHOH*). Our results indicate the possibility that (de)hydrogenation chemistry is rate-controlling in many small polyoxygenate biomass derivatives, and suitable catalysts are needed. Finally, DFT was used to understand the increased decomposition activity observed on the surface segregated Ni-Pt-Pt bimetallic catalyst. It was found that the initial O-H bond breaking of glycolaldehyde to OCH(2)CHO* has an activation barrier of just 0.21 eV. This barrier is lower than that of any glycolaldehyde consuming reaction on Pt. These computational predictions are in qualitative agreement with experimental results. PMID:22483365

Salciccioli, Michael; Vlachos, Dionisios G

2012-04-26

381

[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

382

Pseudospinodal mode of decomposition in films and formation of chessboard-like nanostructure.  

PubMed

A new decomposition mode, a coherent pseudospinodal decomposition under geometrically confined conditions, is discovered. This mode is associated with a coupling of the decomposition with the displacive crystal lattice rearrangement and results in a gradual separation of compositions of two product phases. We consider a particular case of decomposition in an epitaxial thin film. The 3D phase field microelasticity modeling demonstrates that the confined pseudospinodal decomposition dramatically affects the thermodynamics, kinetics and morphology of the system producing a vertically aligned and highly correlated regular chessboard pattern of two product phases. The study reveals the physical origin of the chessboard structure. The computer modeling predicts its geometry in striking agreement with the existing observations. The modeling shows that the transformation develops through a so-called tweed precursor state observed in many martensitic systems. PMID:19639986

Ni, Yong; Rao, Weifeng; Khachaturyan, Armen G

2009-09-01

383

Decomposition pathways in age hardening of Ti-Al-N films  

NASA Astrophysics Data System (ADS)

The ability to increase the thermal stability of protective coatings under work load gives rise to scientific and industrial interest in age hardening of complex nitride coating systems such as ceramic-like Ti1-xAlxN. However, the decomposition pathway of these systems from single-phase cubic to the thermodynamically stable binary nitrides (cubic TiN and wurtzite AlN), which are essential for age hardening, are not yet fully understood. In particular, the role of decomposition kinetics still requires more detailed investigation. In the present work, the combined effect of annealing time and temperature upon the nano-structural development of Ti0.46Al0.54N thin films is studied, with a thermal exposure of either 1 min or 120 min in 100 °C steps from 500 °C to 1400 °C. The impact of chemical changes at the atomic scale on the development of micro-strain and mechanical properties is studied by post-annealing investigations using X-ray diffraction, nanoindentation, 3D-atom probe tomography and high-resolution transmission electron microscopy. The results clearly demonstrate that the spinodal decomposition process, triggering the increase of micro-strain and hardness, although taking place throughout the entire volume, is enhanced at high diffusivity paths such as grain or column boundaries and followed within the grains. Ab initio calculations further show that the early stages of wurtzite AlN precipitation are connected with increased strain formation, which is in excellent agreement with experimental observations.

Rachbauer, R.; Massl, S.; Stergar, E.; Holec, D.; Kiener, D.; Keckes, J.; Patscheider, J.; Stiefel, M.; Leitner, H.; Mayrhofer, P. H.

2011-07-01

384

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

385

Thermal Decomposition of Furan Generates Propargyl Radicals  

SciTech Connect

The thermal decomposition of furan has been studied by a 1 mm x 2 cm tubular silicon carbide reactor, C{sub 4}H{sub 4}O + {Delta} {yields} products. Unlike previous studies, these experiments are able to identify the initial furan decomposition products. Furan is entrained in either He or Ar carrier gas and is passed through a heated (1600 K) SiC tubular reactor. Furan decomposes during transit through the tubular reactor (approximately 65 {micro}s) and exits to a vacuum chamber. Within one nozzle diameter of leaving the nozzle, the gases cool to less than 50 K, and all reactions cease. The resultant molecular beam is interrogated by photoionization mass spectroscopy as well as infrared spectroscopy. Earlier G2(MP2) electronic structure calculations predicted that furan will thermally decompose to acetylene, ketene, carbon monoxide, and propyne at lower temperatures. At higher temperatures, these calculations forecast that propargyl radical could result. We observe all of these species (see Scheme 1). As the pressure in the tubular reactor is raised, the photoionization mass spectra show clear evidence for the formation of aromatic hydrocarbons.

Vasiliou, A.; Nimlos, M. R.; Daily, J. W.; Ellison, G. B.

2009-07-01

386

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

387

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

388

Isospin fluctuations in spinodal decomposition  

SciTech Connect

We study the isospin dynamics in fragment formation within the framework of an analytical model based on the spinodal decomposition scenario. We calculate the probability to obtain fragments with given charge and neutron number, focussing on the derivation of the width of the isotopic distributions. Within our approach this is determined by the dispersion of N/Z among the leading unstable modes, due to the competition between Coulomb and symmetry energy effects, and by isovectorlike fluctuations present in the matter that undergoes the spinodal decomposition. Hence the widths exhibit a clear dependence on the properties of the equation of state. By comparing two systems with different values of the charge asymmetry we find that the isotopic distributions reproduce an isoscaling relationship.

Colonna, M.; Matera, F. [Laboratori Nazionali del Sud, Via S. Sofia 44, I-95123 Catania (Italy); Dipartimento di Fisica, Universita degli Studi di Firenze and Istituto Nazionale di Fisica Nucleare, Sezione di Firenze, Via G. Sansone 1, I-50019 Sesto F. no, Florence (Italy)

2005-06-01

389

A new seismogeodetic approach applied to GPS and accelerometer observations of the 2012 Brawley seismic swarm: Implications for earthquake early warning  

NASA Astrophysics Data System (ADS)

The 26 August 2012 Brawley seismic swarm of hundreds of events ranging from M1.4 to M5.5 in the Salton Trough, California provides a unique data set to investigate a new seismogeodetic approach that combines Global Positioning System (GPS) and accelerometer observations to estimate displacement and velocity waveforms. First in simulated real-time mode, we analyzed 1-5 Hz GPS data collected by 17 stations fully encircling the swarm zone at near-source distances up to about 40 km using precise point positioning with ambiguity resolution (PPP-AR). We used a reference network of North American GPS stations well outside the region of deformation to estimate fractional-cycle biases and satellite clock parameters, which were then combined with ultrarapid orbits from the International GNSS Service to estimate positions during the Brawley seismic swarm. Next, we estimated seismogeodetic displacements and velocities from GPS phase and pseudorange observations and 100-200 Hz accelerations collected at three pairs of GPS and seismic stations in close proximity using a new tightly coupled Kalman filter approach as an extension of the PPP-AR process. We can clearly discern body waves in the velocity waveforms, including P-wave arrivals not detectable with the GPS-only approach for earthquake magnitudes as low as Mw 4.6 and significant static offsets for magnitudes as low as Mw 5.4. Our study shows that GPS networks upgraded with strong motion accelerometers can provide new information for improved understanding of the earthquake rupture process and be of critical value in creating a robust early warning system for any earthquake of societal significance.

Geng, Jianghui; Bock, Yehuda; Melgar, Diego; Crowell, Brendan W.; Haase, Jennifer S.

2013-07-01

390

Optical and 21-cm observations of high-velocity gas towards subdwarfs in the halo and early-type stars in the disk  

NASA Astrophysics Data System (ADS)

We present a study of high-velocity gas in the direction of 13 halo sub-dwarfs located at absolute value of z approximately equals 0.5-2 kpc and of 8 early-type stars in the Galactic disk at d approximately equals 1-4 kpc. For each line of sight of our sample we collected Ca II and Na I absorption spectra with the 2.5-m Isaac Newton Telescope at La Palma (Spain) and H I 21-cm emission profiles with the 100-m radiotelescope at Effelsberg (Germany). The faint sub-dwarfs (mv approximately equals 11-14) are observed for the first time at relatively high spectral resolution (approximately equals 25-30 km/s) in the optical. By comparing the optical absorptions (or upper limits) with the 21-cm emissions, we constrain the distances to the concentrations of neutral gas at high velocity named Complex C, Complex H, and for high velocity gas located between the Cohen Stream and the Magellanic Stream. We find new evidence for gas at intermediate velocity in the halo and in the disk of our Galaxy.

Centurion, M.; Vladilo, G.; de Boer, K. S.; Herbstmeier, U.; Schwarz, U. J.

1994-12-01

391

Subaru/COMICS Mid-Infrared Observation of the Near-Nucleus Region of Comet 17P/Holmes at the Early Phase of an Outburst  

NASA Astrophysics Data System (ADS)

Mid-infrared 8--25?m imaging and spectroscopic observations of the comet 17P/Holmes in the early phase of its outburst in brightness were performed on 2007 October 25--28UT using the Cooled Mid-Infrared Camera and Spectrometer (COMICS) on the 8.2-m Subaru Telescope. We detected an isolated dust cloud that moved toward the south-west direction from the nucleus. The 11.2?m peak of a crystalline silicate feature onto a broad amorphous silicate feature was also detected both in the central condensation of the nucleus and an isolated dust cloud. The color temperature of the isolated dust cloud was estimated to be ˜200K, which is slightly higher than the black-body temperature. Our analysis of the motion indicates that the isolated cloud moved anti-sunward. We propose several possibilities for the motion of the cloud: fluffy dust particles in the isolated cloud started to depart from the nucleus due to radiation pressure almost as soon as the main outburst occurred, or dust particles moved by some other anti-sunward forces, such as a rocket effect and photophoresis when the surrounding dust coma became optically thin. The origin and the nature of the isolated dust cloud are discussed in this paper.

Watanabe, Jun-Ichi; Honda, Mitsuhiko; Ishiguro, Masateru; Ootsubo, Takafumi; Sarugaku, Yuki; Kadono, Toshihiko; Sakon, Itsuki; Fuse, Tetsuharu; Takato, Naruhisa; Furusho, Reiko

2009-08-01

392

The Experience of a Multidisciplinary Clinic in the Management of Early-Stage Breast Cancer Patients Receiving Trastuzumab Therapy: An Observational Study  

PubMed Central

Background. We established a dedicated cardiac oncology clinic in 2008 for the rapid diagnosis and treatment of cardiotoxicity related to cancer therapy. In this retrospective observational study, we report on clinical outcomes in women with early-stage breast cancer (EBC) referred to this clinic. Methods. Patients with EBC treated with chemotherapy/trastuzumab and referred between October 2008 and December 2010. Data included patient demographics, staging, cancer treatment/completion, dose delays, left ventricular ejection fraction (LVEF) and cardiac treatment. Results. Forty eight patients: median age 55.5 years, stage I/II disease (77%) and HER-2 positive (98%). The majority of women (n = 32) were referred for decreases in LVEF (from baseline). Overall, 37 (77%) patients experienced at least one drop in LVEF while on treatment, of which 22 patients (59%) experienced a ?10 percentage point drop. The majority of patients (30/37; 81%) experienced declines in LVEF while on trastuzumab. Interventions included trastuzumab delays (n = 16/48; 33%) and cardiac medication (12/48: 25%). A total of 81% of patients completed ?90% of trastuzumab therapy and 15% of patients discontinued therapy due to cardiotoxicity. Conclusion. The majority of patients referred to our clinic completed therapy. Further studies are needed to determine the impact of this multidisciplinary approach on treatment completion and cardiac outcomes.

Dent, Susan; Hopkins, Sean; Graham, Nadine; Johnson, Christopher; Law, Angeline; Campbell, Michelle; Crawley, Freya; Allen, Kathleen; Turek, Michele

2012-01-01

393

The Decomposition of Human Remains  

Microsoft Academic Search

The end result of decomposition of humans is more intimately familiar and perhaps of greater interest to forensic pathologists\\u000a than to any other group whose duties include the evaluation and investigation of postmortem remains on a routine basis. From\\u000a such remains, the forensic pathologist may be asked to make an evaluation of the cause and manner of death and, perhaps,

Robert H. Powers

394

Discrete multiscale vector field decomposition  

Microsoft Academic Search

While 2D and 3D vector fields are ubiquitous in computational sciences, their use in graphics is often limited to regular grids, where computations are easily handled through finite-difference methods. In this paper, we propose a set of simple and accurate tools for the analysis of 3D discrete vector fields on arbitrary tetrahedral grids. We introduce a variational, multiscale decomposition of

Yiying Tong; Santiago V. Lombeyda; Anil N. Hirani; Mathieu Desbrun

2003-01-01

395

Spinodal decomposition of beta brass  

Microsoft Academic Search

An electron microscopy study has been carried out to determine the origin of diffuse satellite reflections appearing in the\\u000a electron diffraction patterns of the metastable CsCl type phase in Cu-38.9 and Cu-47.3 at. pct Zn alloys. It has been shown\\u000a that two different kinds of satellite reflections appear: one set arises because of spinodal decomposition at low temperatures\\u000a near room

H. Kubo; M. Wayman

1979-01-01

396

Spinodal decomposition in 3-space  

Microsoft Academic Search

Using a cell-dynamical system (CDS) to model the separation of phases, we present the results of large-scale simulations of spinodal decomposition in 3-space of a symmetric binary alloy and incompressible binary fluid at critical quench. Our main results are (1) the reliable determination of the asymptotic or the almost asymptotic form factors for these systems, and (2) an understanding of

Aritomo Shinozaki; Yoshitsugu Oono

1993-01-01

397

Thermooxidative decomposition of oil shales  

Microsoft Academic Search

The thermooxidative decomposition of four oil shale samples from Estonia, Jordan, Israel and Morocco and one sample of Estonian\\u000a oil shale derivative, semicoke, was studied with the aim to determine the characteristics of the process and the differences\\u000a of it related to the origin of oil shale. The experiments with a Setaram Setsys 1750 thermoanalyzer coupled to a Nicolet 380

Tiit Kaljuvee; Merli Keelmann; Andres Trikkel; Rein Kuusik

2011-01-01

398

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

399

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

400

The Fourier Decomposition of the Light Curves of High Amplitude ? Sct Stars  

NASA Astrophysics Data System (ADS)

A significant improvement of the relationships between observed and physical properties of high amplitude ? Scuti stars (HADS), SX Phe stars, and RRc stars can be obtained by the systematic application of Fourier decomposition to their light curves.

Poretti, E.

401

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

402

Leaf litter mixtures alter microbial community development: mechanisms for non-additive effects in litter decomposition.  

PubMed

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. PMID:23658639

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

2013-04-29

403

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

404

Photocatalysis of chloroform decomposition by the hexachlororuthenate(IV) ion.  

PubMed

Dissolved hexachlororuthenate(IV) effectively catalyzes the photodecomposition of chloroform to hydrogen chloride and phosgene under near-UV (? > 345 nm) irradiation, whereby RuCl6(2-) is not itself photocatalytically active, but is photochemically transformed into a species that is active, possibly RuCl5 (CHCl3 )(-) . Conversion to a photoactive species during irradiation is consistent with the acceleration of the decomposition rate during the early stages and with the apparent inverse dependence of the decomposition rate on the initial concentration of RuCl6(2-) . The displacement of Cl(-) by CHCl3 in the coordination sphere to create the photoactive species is consistent with the retardation of photodecomposition by both Cl(-) and H2 O. The much smaller photodecomposition rate in CDCl3 suggests that C-H bond dissociation occurs during the primary photochemical event, which is also consistent with the presence of a CHCl3 molecule in the first coordination sphere. PMID:23050803

Chan, Alissa M; Peña, Laura A; Segura, Rosa E; Auroprem, Ramya; Harvey, Brent M; Brooke, Caroline M; Hoggard, Patrick E

2012-11-08

405

Temperature sensitivity of soil carbon decomposition and feedbacks to climate change.  

PubMed

Significantly more carbon is stored in the world's soils--including peatlands, wetlands and permafrost--than is present in the atmosphere. Disagreement exists, however, regarding the effects of climate change on global soil carbon stocks. If carbon stored belowground is transferred to the atmosphere by a warming-induced acceleration of its decomposition, a positive feedback to climate change would occur. Conversely, if increases of plant-derived carbon inputs to soils exceed increases in decomposition, the feedback would be negative. Despite much research, a consensus has not yet emerged on the temperature sensitivity of soil carbon decomposition. Unravelling the feedback effect is particularly difficult, because the diverse soil organic compounds exhibit a wide range of kinetic properties, which determine the intrinsic temperature sensitivity of their decomposition. Moreover, several environmental constraints obscure the intrinsic temperature sensitivity of substrate decomposition, causing lower observed 'apparent' temperature sensitivity, and these constraints may, themselves, be sensitive to climate. PMID:16525463

Davidson, Eric A; Janssens, Ivan A

2006-03-01

406

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

407

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

408

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

409

Impact of prior CKD management in a renal care network on early outcomes in incident dialysis patients: a prospective observational study  

PubMed Central

Background Effective therapeutic strategies are available to prevent adverse outcomes in patients with chronic kidney disease (CKD) but their clinical results are hindered by unplanned implementation. Coordination of care emerges as a suitable way to improve patient outcomes. In this study, we evaluated the effect of planned and coordinated patient management within a dedicated renal care network comparatively to standard renal care delivered in nephrology departments of teaching hospitals. Methods This observational matched cohort study included 40 patients with CKD stage 4–5 in the network group as compared with a control group of 120 patients matched for age, sex and diabetic status. Main outcome was a composite endpoint of death from cardiovascular cause and cardiovascular events during the first year after dialysis initiation. Results There was no difference between the two groups neither for the primary outcome (40% vs 41%) nor for the occurrence of death from cardiovascular cause or cardiovascular events. Whereas the proportion of patients requiring at least one hospitalization was identical (83.3% vs 75%), network patients experienced less individual hospitalizations than control patients (2.3±2.0 vs 1.6±1.7) during the year before dialysis start. Patients of the network group had a slower renal function decline (7.7±2.5 vs 4.9±1.1 ml/min/1,73m2 per year; p=0.04). Conclusions In this limited series of patients, we were unable to demonstrate a significant impact of the coordinated renal care provided in the network on early cardiovascular events in incident dialysis patients. However, during the predialysis period, there were less hospitalizations and a slower slope of renal function decrease.

2013-01-01

410

Cumulative funnel plots for the early detection of interoperator variation: retrospective database analysis of observed versus predicted results of percutaneous coronary intervention  

PubMed Central

Objective To use funnel plots and cumulative funnel plots to compare in-hospital outcome data for operators undertaking percutaneous coronary interventions with predicted results derived from a validated risk score to allow for early detection of variation in performance. Design Analysis of prospectively collected data. Setting Tertiary centre NHS hospital in the north east of England. Participants Five cardiologists carrying out percutaneous coronary interventions between January 2003 and December 2006. Main outcome measures In-hospital major adverse cardiovascular and cerebrovascular events (in-hospital death, Q wave myocardial infarction, emergency coronary artery bypass graft surgery, and cerebrovascular accident) analysed against the logistic north west quality improvement programme predicted risk, for each operator. Results are displayed as funnel plots summarising overall performance for each operator and cumulative funnel plots for an individual operator’s performance on a case series basis. Results The funnel plots for 5198 patients undergoing percutaneous coronary interventions showed an average observed rate for major adverse cardiovascular and cerebrovascular events of 1.96% overall. This was below the predicted risk of 2.06% by the logistic north west quality improvement programme risk score. Rates of in-hospital major adverse cardiovascular and cerebrovascular events for all operators were within the 3? upper control limit of 2.75% and 2? upper warning limit of 2.49%. Conclusion The overall in-hospital major adverse cardiovascular and cerebrovascular events rates were under the predicted event rate. In-hospital rates after percutaneous coronary intervention procedure can be monitored successfully using funnel and cumulative funnel plots with 3? control limits to display and publish each operator’s outcomes. The upper warning limit (2? control limit) could be used for internal monitoring. The main advantage of these charts is their transparency, as they show observed and predicted events separately. By this approach individual operators can monitor their own performance, using the predicted risk for their patients but in a way that is compatible with benchmarking to colleagues, encapsulated by the funnel plot. This methodology is applicable regardless of variations in individual operator case volume and case mix.

2008-01-01

411

Star Formation Rates and Stellar Masses of z = 7-8 Galaxies from IRAC Observations of the WFC3/IR Early Release Science and the HUDF Fields  

NASA Astrophysics Data System (ADS)

We investigate the Spitzer/IRAC properties of 36 z ~ 7 z 850-dropout galaxies and three z ~ 8 Y 098 galaxies derived from deep/wide-area WFC3/IR data of the Early Release Science, the ultradeep HUDF09, and wide-area NICMOS data. We fit stellar population synthesis models to the spectral energy distributions to derive mean redshifts, stellar masses, and ages. The z ~ 7 galaxies are best characterized by substantial ages (>100 Myr) and M/LV ? 0.2. The main trend with decreasing luminosity is that of bluing of the far-UV slope from ? ~ -2.0 to ? ~ -3.0. This can be explained by decreasing metallicity, except for the lowest luminosity galaxies (0.1L* z = 3), where low metallicity and smooth star formation histories (SFHs) fail to match the blue far-UV and moderately red H - [3.6] color. Such colors may require episodic SFHs with short periods of activity and quiescence ("on-off" cycles) and/or a contribution from emission lines. The stellar mass of our sample of z ~ 7 star-forming galaxies correlates with star formation rate (SFR) according to log M* = 8.70(±0.09) + 1.06(±