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1

Observation of Periodic Spinodal Decomposition  

NASA Astrophysics Data System (ADS)

Periodic spinodal decomposition has been observed in a critical binary mixture of isobutyric acid and water. As predicted by Onuki, phase separation can be dramatically slowed down by a periodic quench of appropriately chosen mean value and amplitude of the temperature variations. Depending on details of the quench conditions, two steady-state conditions can be achieved, in one of which the system has completely separated.

Joshua, M.; Maher, J. V.; Goldburg, W. I.

1983-07-01

2

Evidence for Early Morphological Decomposition: Combining Masked Priming with Magnetoencephalography  

ERIC Educational Resources Information Center

Are words stored as morphologically structured representations? If so, when during word recognition are morphological pieces accessed? Recent masked priming studies support models that assume early decomposition of (potentially) morphologically complex words. The electrophysiological evidence, however, is inconsistent. We combined masked…

Lehtonen, Minna; Monahan, Philip J.; Poeppel, David

2011-01-01

3

Student Loans and Early Post-Graduation Earnings: Evidence from Decomposition Analysis1  

E-print Network

1 Student Loans and Early Post-Graduation Earnings: Evidence from Decomposition Analysis1 Serguey lower earnings than graduates without loans. Decomposition estimations show that most of the earnings on borrowing. This version: February 3, 2012 JEL Codes [I22, J24, J31] Keywords: human capital, student loans

Braguinsky, Serguey

4

Intermediate Phases Observed During Decomposition of LiBH4  

SciTech Connect

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

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

2007-01-01

5

Evidence for Early Morphological Decomposition in Visual Word Recognition  

Microsoft Academic Search

We employ a single-trial correlational MEG analysis technique to investigate early processing in the visual recognition of morphologically complex words. Three classes of affixed words were presented in a lexical decision task: free stems (e.g., taxable), bound roots (e.g., tolerable), and unique root words (e.g., vulnerable, the root of which does not appear elsewhere). Analysis was focused on brain responses

Olla Solomyak; Alec Marantz

2009-01-01

6

Evidence for Early Morphological Decomposition in Visual Word Recognition  

Microsoft Academic Search

We employ a single-trial correlational MEG analysis technique to investigate early processing in the visual recognition of mor- phologically complex words. Three classes of affixed words were presented in a lexical decision task: free stems (e.g., taxable), bound roots (e.g., tolerable), and unique root words (e.g., vulner- able, the root of which does not appear elsewhere). Analysis was focused on

Olla Solomyak; Alec Marantz

2010-01-01

7

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

8

Stress-Diffusion Coupling and Viscoelastic Effects on Early Stage Spinodal Decomposition in Polymer Solutions  

NASA Astrophysics Data System (ADS)

We investigated the viscoelastic effects on the early stage spinodal decomposition (SD) in semidilute polymer solutions where the coupling of stress and diffusion plays an important role. The so-called viscoelastic length ?ve, within which the stress suppresses the growth of the concentration fluctuations, was quantitatively evaluated experimentally. The evaluated value was found out to become as large as 9.0×102 nm. The obtained value ?ve agrees well with that independently estimated from the diffusion and viscoelasticity measurements, indicating that the Doi-Onuki theory can well describe the viscoelastic effects on the dynamics of the early stage SD.

Takenaka, Mikihito; Toyoda, Nobuyuki; Saito, Shin; Hashimoto, Takeji

9

Polar decomposition for attitude determination from vector observations  

NASA Technical Reports Server (NTRS)

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

Bar-Itzhack, Itzhack Y.

1993-01-01

10

Acousto-spinodal decomposition of compressible polymer solutions: Early stage analysis  

NASA Astrophysics Data System (ADS)

The structure and dynamics of early stage kinetics of pressure-induced phase separation of compressible polymer solutions via spinodal decomposition is analyzed using a linear Euler-Cahn-Hilliard model and the modified Sanchez Lacombe equation of state. The integrated density wave and Cahn-Hilliard equations combine the kinetic and structural characteristics of spinodal decomposition with density waves arising from pressure-induced couplings. When mass transfer rate is slower that acoustic waves, concentration gradients generate density waves that cycle back into the spinodal decomposition dynamics, resulting in oscillatory demixing. The wave attenuation increases with increasing mass transfer rates eventually leading to nonoscillatory spinodal demixing. The novel aspects of acousto-spinodal decomposition arise from the coexistence of stable oscillatory density dynamics and the unstable monotonic concentration dynamics. Scaling laws for structure and dynamics indicate deviations from incompressible behavior, with a significant slowing down of demixing due to couplings with density waves. Partial structure factors for density and density-concentration reflect the oscillatory nature of acousto-spinodal modes at lower wave vectors, while the single maximum at a constant wave vector reflects the presence of a dominant mode in the linear regime. The computed total structure factor is in qualitative agreement with experimental data for a similar polymer solution.

Rasouli, Ghoncheh; Rey, Alejandro D.

2011-05-01

11

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

2007-10-15

12

Early spectroscopic observations of four extragalactic novae  

NASA Astrophysics Data System (ADS)

We report the spectroscopic observations of four extragalactic novae in M31 and in M33, secured at Loiano Observatory, Italy. Nova M31 2009-10b is a luminous nova that needed some days to achieve the peak brightness. We confirm that it is a Fe II nova and we show that it is one of the most luminous novae ever observed in M31, showing an evolution close to that of the bright extragalactic novae M31 2007-11d, LMC 1991 and SN 2010U. The novae M31 2010-07a and M31 2011-07b are standard Fe II novae. Nova M33 2010-07a is a Fe II nova that showed a peculiar rebrightening, during which we observed emission lines with P Cyg profiles: we suggest that it is the first observed nova in M33 that underwent a second mass ejection.

Poggiani, R.

2015-05-01

13

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

14

The Early Years: Observing with Magnifiers  

ERIC Educational Resources Information Center

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

Ashbrook, Peggy

2008-01-01

15

Some observations on early military anaesthesia.  

PubMed

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

Houghton, I T

2006-06-01

16

Early Reading and Giftedness--Some Observations and Questions.  

ERIC Educational Resources Information Center

Interviews with parents of children who were early readers and observation of reading performance in informal settings revealed a number of characteristics shared by the children, including early interest in alphabet letters and regular viewing of "Sesame Street" on television. (CL)

Salzer, Richard T.

1984-01-01

17

Early time optical observations of GRB afterglows and their implications  

NASA Astrophysics Data System (ADS)

Early time optical observations of GRBs are very important towards revealing the prompt emission and afterglow properties of these energetic explosions. The observations of the well-studied GRBs by Swift indicate that early time properties of the optical light-curves share diverse set of features broadly consistent with the predictions made by various afterglow models though outliers exists. 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 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 smooth rise and decay 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.

Bhushan Pandey, Shashi

18

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

SciTech Connect

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){sub 3}) to bixbyite-type indium oxide (c-In{sub 2}O{sub 3}). The electron beam is focused onto a single cube-shaped In(OH){sub 3} crystal of {l_brace}100{r_brace} 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-In{sub 2}O{sub 3} 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){sub 3} is transformed to a diffuse strongly textured ring-like pattern of c-In{sub 2}O{sub 3} that indicates the transformed cube is no longer a single crystal but is disintegrated into individual c-In{sub 2}O{sub 3} 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-In{sub 2}O{sub 3}), calculated from the shrinkage of the parent c-In(OH){sub 3} crystal in the recorded HR-TEM images, is used as a measure of the kinetics of c-In{sub 2}O{sub 3} crystallization within the framework of Avrami-Erofeev formalism. The Avrami exponent of {approx}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){sub 3} to c-In{sub 2}O{sub 3} is discussed in terms of (i) the displacement of hydrogen atoms that lead to breaking the hydrogen bond between OH groups of [In(OH){sub 6}] octahedra and finally to their destabilization and (ii) transformation of the vertices-shared indium-oxygen octahedra in c-In(OH){sub 3} to vertices- and edge-shared octahedra in c-In{sub 2}O{sub 3}. - Graphical abstract: Frame-by-frame analysis of video sequences recorded of HR-TEM images reveals that a single cube-shaped In(OH){sub 3} nanocrystal with {l_brace}100{r_brace} morphology decomposes into bixbyite-type In{sub 2}O{sub 3} domains while being imaged. The mechanism of this decomposition is evaluated through the analysis of the structural relationship between initial (c-In(OH){sub 3}) and transformed (c-In{sub 2}O{sub 3}) phases and though the kinetics of the decomposition followed via the time-resolved shrinkage of the initial crystal of indium hydroxide. Highlights: Black-Right-Pointing-Pointer In-situ time-resolved High Resolution Transmission Electron Microscopy. Black-Right-Pointing-Pointer Crystallographic transformation path. Black-Right-Pointing-Pointer Kinetics of the decomposition in one nanocrystal.

Miehe, Gerhard; Lauterbach, Stefan; Kleebe, Hans-Joachim [Technische Universitaet Darmstadt, Fachbereich Material- und Geowissenschaften, Petersenstr. 23, 64287 Darmstadt (Germany)] [Technische Universitaet Darmstadt, Fachbereich Material- und Geowissenschaften, Petersenstr. 23, 64287 Darmstadt (Germany); Gurlo, Aleksander, E-mail: gurlo@materials.tu-darmstadt.de [Technische Universitaet Darmstadt, Fachbereich Material- und Geowissenschaften, Petersenstr. 23, 64287 Darmstadt (Germany)] [Technische Universitaet Darmstadt, Fachbereich Material- und Geowissenschaften, Petersenstr. 23, 64287 Darmstadt (Germany)

2013-02-15

19

Observations and evolution of hot coronae around early type galaxies  

NASA Technical Reports Server (NTRS)

This review describes obervations of hot coronae around early-type galaxies. The observations show that early-type galaxies have 0.5-4.5 keV luminosities up to nearly 10 to the 43rd ergs/sec dominated by thermal emission from 10 to the 10th solar masses of hot (about 10 to the 7th K) gas. Calculations which model the evolution of the coronae are presented. These models can explain the present epoch observations as well as predict the coronal properties at large redshift.

Forman, W.; Jones, C.; David, L.; Tucker, W.

1990-01-01

20

Viscoelastic effects on early stage of spinodal decomposition in dynamically asymmetric polymer blends  

NASA Astrophysics Data System (ADS)

Spinodal decomposition induced by a rapid pressure change was investigated for a dynamically asymmetric polymer blend [deuterated polybutadiene (DPB)/polyisoprene (PI)] with a composition of 50/50wt/wt by using time-resolved small angle neutron scattering. The time change in the scattered intensity distribution with wave number (q) during the spinodal decomposition was found to be approximated by the Doi-Onuki theory [M. Doi and A. Onuki, J. Phys. II 2, 1631 (1992)]. The theoretical analysis yielded the q dependence of the Onsager kinetic coefficient which is characterized by the q-2 dependence at q?ve>1 with the characteristic length ?ve being much larger than the radius of gyration of DPB or PI. The estimated ?ve agrees well with that obtained previously in the relaxation processes induced by pressure change within the one phase region for the same blend.

Takenaka, Mikihito; Takeno, Hiroyuki; Hashimoto, Takeji; Nagao, Michihiro

2006-03-01

21

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

22

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

NASA Astrophysics Data System (ADS)

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

Lin, Jin-Ming; Liu, Meilin

2009-02-01

23

Spectral types for early-type stars observed by Skylab  

NASA Technical Reports Server (NTRS)

MK spectral types are presented for 246 early-type stars observed with the S-019 ultraviolet stellar astronomy experiment on Skylab. K-line types are also given where applicable, and various peculiar stars are identified. The peculiar stars include five silicon stars, a shell star, a helium-rich star, a silicon-strontium star, a chromium-europium star, and two marginal metallic-line stars.

Roman, N. G.

1978-01-01

24

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

ERIC Educational Resources Information Center

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

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

2008-01-01

25

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

26

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

NASA Technical Reports Server (NTRS)

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

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

1972-01-01

27

Observations of hydroxyl in early-type galaxies  

NASA Astrophysics Data System (ADS)

We used Arecibo Observatory and the Green Bank Telescope to observe OH in 12 early-type galaxies with known reservoirs of dense gas. We present three new detections of OH in absorption in the 1667 MHz line. One objective of our survey was to find evidence of molecular outflows, but our sensitivity and the strength of the OH absorption were insufficient to detect outflows. The detected sources have infrared luminosities and dust temperatures among the lowest of any galaxy detected in OH absorption. The ratio LHCN/LCO, a measure of the dense gas fraction in galaxies, is a powerful selector of OH megamasers for galaxies with high infrared luminosity. In early-type galaxies, which have much lower infrared luminosities, LHCN/LCO is also a promising tool for discovering OH, but in absorption rather than in maser emission. In addition to dense molecular gas, a radio continuum source and a favourable line of sight to the observer are likely key factors in detecting OH absorbers.

McBride, James; Alatalo, Katherine; Nyland, Kristina

2015-02-01

28

Acquiring Comprehensive Observations using an Integrated Sensorweb for Early Warning  

NASA Technical Reports Server (NTRS)

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

Habib, Shahid; Ambrose, Steve

2006-01-01

29

Acquiring Comprehensive Observations using an integrated Sensorweb for Early Warning  

NASA Technical Reports Server (NTRS)

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

Habib, Shahid; Ambrose, Steve

2006-01-01

30

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

ERIC Educational Resources Information Center

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

Nyland, Berenice; Alfayez, Shatha

2012-01-01

31

Constraining Perturbative Early Dark Energy with Current Observations  

NASA Astrophysics Data System (ADS)

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 wm >~ -0.1 at early times, which could lead to an EDE density of up to ?_{{DE}} (z_CMB)= 0.03 ?_m(z_CMB). Our analysis shows that marginalizing over the non-DE parameters such as ?m, H 0, andns , current CMB observations alone can constrain the scale factor of transition from EDE to late-time dark energy to at >~ 0.44 and width of transition to ? t <~ 0.37. The equation of state at present is somewhat weakly constrained to w 0 <~ -0.6, if we allow H 0 < 60 km s-1 Mpc-1. Taken together with other observations, such as SNe, Hubble Space Telescope, and Sloan Digital Sky Survey luminous red galaxies, w 0 is constrained much more tightly to w 0 <~ -0.9, while redshift of transition and width of transition are also tightly constrained to at <~ 0.19 and? t <~ 0.21. The evolution of the equation of state for EDE models is thus tightly constrained to ?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 0 <~ -0.8, at <~ 0.33, and? t <~ 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 0 <~ -0.77, at <~ 0.35, and? t <~ 0.35 with -0.014 < ?? < 0.031 for CMB + other observations. For perturbed EDE models, the 2? lower limit on ?8 (?8 >= 0.59) is much lower than that in ?CDM (?8 >= 0.72), thus raising the interesting possibility of discriminating EDE from ?CDM using future observations such as halo mass functions or the Sunyaev-Zeldovich power spectrum.

Alam, Ujjaini

2010-05-01

32

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

33

Observations of Neutron-Capture Elements in the Early Galaxy  

E-print Network

Neutron-capture elements in low metallicity Galactic halo stars vary widely both in overall contents and detailed abundance patterns. This review discusses recent observational results on the n-capture elements, discussing the implications for early Galactic nucleosynthesis of: (a) the star-to-star ``bulk'' variations in the n-capture/Fe abundance ratios; (b) the distinct signature of rapid n-capture synthesis events in many (most?) of the lowest metallicity stars; (c) the existence of metal-poor stars heavily enriched in the products of slow n-capture synthesis reactions; and (d) the now-routine detection of radioactive thorium (and even uranium in one and possibly two cases) in the spectra of metal-poor stars.

C. Sneden; J. J. Cowan; J. E. Lawler

2002-10-04

34

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

35

Aminoxyl (nitroxyl) radicals in the early decomposition of the nitramine RDX.  

PubMed

The explosive nitramine RDX (1,3,5-trinitrohexahydro-s-triazine) is thought to decompose largely by homolytic N-N bond cleavage, among other possible initiation reactions. Density-functional theory (DFT) calculations indicate that the resulting secondary aminyl (R2N·) radical can abstract an oxygen atom from NO2 or from a neighboring nitramine molecule, producing an aminoxyl (R2NO·) radical. Persistent aminoxyl radicals have been detected in electron-spin resonance (ESR) experiments and are consistent with autocatalytic "red oils" reported in the experimental literature. When the O-atom donor is a nitramine, a nitrosamine is formed along with the aminoxyl radical. Reactions of aminoxyl radicals can lead readily to the "oxy-s-triazine" product (as the s-triazine N-oxide) observed mass-spectrometrically by Behrens and co-workers. In addition to forming aminoxyl radicals, the initial aminyl radical can catalyze loss of HONO from RDX. PMID:23373538

Irikura, Karl K

2013-03-14

36

Intercomparison between observed and simulated variability in global ocean heat content using empirical mode decomposition, part I: modulated annual cycle  

NASA Astrophysics Data System (ADS)

This study proposes a new more precise and detailed method to examine the performance of IPCC AR4 models in simulation of nonlinear variability of global ocean heat content (OHC) on the annual time scale during 1950-1999. The method is based on the intercomparison of modulated annual cycle (MAC) of OHC and its instantaneous frequency (IF), derived by Empirical Mode Decomposition and Hilbert-Huang Transformation. In addition to indicate the general agreement in gross features globally between models and observation, our results point out the problems both in observation and in modeling. In the well observed Northern Hemisphere, models exhibit extremely good skills to capture nonlinear annual variability of OHC. The simulated MACs are highly correlated with observations (>0.95) and the IF of MACs varies coherently with each other. However, in sparsely observed Southern Hemisphere (SH), even though the simulated MACs highly correlate with observations, the IF shows significant difference. This comparisons show that the models exhibit coherent variability of IF of MACs in SH with each other, but not with observations, revealing the problems in the objective analyzed dataset using sparse observations. In the well observed tropic region, the models lack the coherence with the observations, indicating inadequate physics of the models in the tropical area. These results illustrate that the proposed method can be used routinely to identify problems in both models and in observation of the global ocean as a critical component of global climate change.

Chen, Xianyao; Zhang, Yuanling; Zhang, Min; Feng, Ying; Wu, Zhaohua; Qiao, Fangli; Huang, Norden Eh

2013-12-01

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

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

40

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

41

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

42

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

NASA Astrophysics Data System (ADS)

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

Barcikowska, Monika; Knutson, Tom

2014-05-01

43

Hubble and Shapley - Two Early Giants of Observational Cosmology  

NASA Astrophysics Data System (ADS)

Observational cosmology of the first decades of the Twentieth Century was dominated by two giants: Edwin Hubble and Harlow Shapley. Hubble's major contributions were to the study and classification of individual galaxies with large telescopes, whereas Shapley is best remembered for his work on groups and clusters of galaxies using telescopes of more modest aperture.

van den Bergh, Sidney

2011-12-01

44

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

45

Basin-scale, integrated observations of the early 21st century multiyear drought  

E-print Network

Basin-scale, integrated observations of the early 21st century multiyear drought in southeast] The Murray-Darling Basin in southeast Australia is experiencing one of the most severe droughts observed. This paper provides new basin-scale observations of the multiyear drought, integrated to a degree rarely

Tregoning, Paul

46

Singular Value Decomposition Proper Orthogonal Decomposition  

E-print Network

Singular Value Decomposition Proper Orthogonal Decomposition Model Order Reduction Techniques SVD;Singular Value Decomposition Proper Orthogonal Decomposition Singulärwerte und -vektoren Eigenschaften / 24 #12;Singular Value Decomposition Proper Orthogonal Decomposition Singulärwerte und -vektoren

47

A New Observation Technique Applied to Early/Fast VLF Scattering Events  

NASA Astrophysics Data System (ADS)

Early/fast very low frequency (VLF, 3-30 kHz) events are understood to result from ionospheric conductivity changes associated with lightning. Early/fast amplitude and phase perturbations have been observed coincidentally with various optical observations of transient luminous events (TLEs), including elves, sprites, and sprite halos, each of which can have temporal characteristics consistent with those of early/fast VLF events. It is yet unresolved, however, whether a specific type of TLE is directly related to the ionospheric conductivity changes responsible for the typical early/fast event. In this paper, we present spread spectrum VLF scattering observations of early/fast events. The spread spectrum analysis technique determines the amplitude and phase of a subionospherically propagating VLF signal as a function of time during the early/fast event and as a function of frequency across the 200 Hz bandwidth of the VLF transmission. VLF scattering observations, each identified with causative lightning logged by the National Lightning Detection Network (NLDN), are compared with the predictions of the Long-Wave Propagation Capability (LWPC) code, a three-dimensional earth-ionosphere waveguide propagation and scattering model. Theoretical predictions for VLF scattering from ionization changes associated with elves are compared with those associated with sprite halos, and each are compared with experimental observations. Results indicate that the observed frequency dependence of VLF scattering during early/fast events results from the combination of scattering source properties and Earth-ionosphere waveguide propagation effects. Observations are more consistent with the modeled amplitude perturbations associated with sprite halos than those with elves.

Kotovsky, D. A.; Moore, R. C.

2012-12-01

48

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

49

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

Microsoft Academic Search

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

H. Christian

2010-01-01

50

Early Optical Follow-up Observations of Gamma Ray Bursts with the Robotic Liverpool Telescope  

E-print Network

counterparts requires both ra- pid and deep observations. Here we discuss the 2-m robotic Liverpool TelescopeEarly Optical Follow-up Observations of Gamma Ray Bursts with the Robotic Liverpool Telescope A, Slovenia 3 ITC-IRST and INFN, Trento, via Sommarive, 18 38050 Povo (TN), Italy Abstract Robotic telescopes

Gomboc, Andreja

51

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

52

Early-type Galaxies in the Sloan Digital Sky Survey. II. Correlations between Observables  

Microsoft Academic Search

A magnitude-limited sample of nearly 9000 early-type galaxies, in the redshift range 0.01<=z<=0.3, was selected from the Sloan Digital Sky Survey using morphological and spectral criteria. The sample was used to study how early-type galaxy observables, including luminosity L, effective radius Ro, surface brightness Io, color, and velocity dispersion sigma, are correlated with one another. Measurement biases are understood with

Mariangela Bernardi; Ravi K. Sheth; James Annis; Scott Burles; Daniel J. Eisenstein; Douglas P. Finkbeiner; David W. Hogg; Robert H. Lupton; David J. Schlegel; Mark SubbaRao; Neta A. Bahcall; John P. Blakeslee; J. Brinkmann; Francisco J. Castander; Andrew J. Connolly; István Csabai; Mamoru Doi; Masataka Fukugita; Joshua Frieman; Timothy Heckman; Zeljko Ivezic; G. R. Knapp; Don Q. Lamb; Timothy McKay; Robert Nichol; Sadanori Okamura; Donald P. Schneider; Aniruddha R. Thakar; Donald G. York

2003-01-01

53

Early-time observations of Type Ia supernovae to reveal progenitor material  

NASA Astrophysics Data System (ADS)

SNe Ia remain nature's best standardized candles, and yet their progenitors have long been a mystery. However, it is now clear that there is a multiplicity of SN Ia progenitors. Recent findings that SNe Ia correct to different absolute magnitudes in different mass galaxies may be related to differing progenitors, and/or explosion physics. With this proposal we will obtrain early GMOS spectroscopy of SNe a few days after explosion with three main goals: (1) trigger our high resolution spectroscopy time on Keck HIRES and VLT X-Shooter to search for circumstellar material indicative of a single degenerate origin, (2) build the first well-controlled sample studying unburned progenitor carbon in SNe Ia, testing whether this traces white dwarf mergers or explosion physics (3) type SNe as early as possible to enable follow-up observations and studies, including cosmology. Our results depend on early-time observations for which the queue-scheduled Gemini is uniquely suited.

Howell, D. Andrew; Parrent, Jerod; Sullivan, Mark; Maguire, Kate; Nugent, Peter; Dilday, Benjamin; Graham, Melissa

2013-02-01

54

Early-time observations of Type Ia supernovae to reveal progenitors and metallicity  

NASA Astrophysics Data System (ADS)

SNe Ia remain nature's best standardized candles, and yet their progenitors have long been a mystery. However, it is now clear that there is a multiplicity of SN Ia progenitors. Recent findings that SNe Ia correct to different absolute magnitudes in different mass galaxies may be related to differing progenitors, and/or progenitor metallicity. With this proposal we will obtrain early GMOS spectroscopy of SNe a few days after explosion with three main goals: (1) to trigger our proposed HST Cycle 20 STIS observations probing early UV spectra and thus metallicity, (2) trigger our high resolution spectroscopy time on Keck HIRES and VLT X-shooter to search for circumstellar material indicative of a single degenerate origin, (3) build the first well-controlled sample studying unburned progenitor carbon in SNe Ia, testing whether this traces white dwarf mergers or explosion physics. Our results depend on early-time observations for which the queue-scheduled Gemini is uniquely suited.

Howell, D. Andrew; Sullivan, Mark; Maguire, Kate; Parrent, Jerod; Nugent, Peter; Ellis, Richard; Dilday, Benjamin; Graham, Melissa; Hook, Isobel

2012-08-01

55

Shock wave induced decomposition of RDX: quantum chemistry calculations.  

PubMed

Quantum chemical calculations on single molecules were performed to provide insight into the decomposition mechanism of shocked RDX. These calculations complement time-resolved spectroscopy measurements on shock wave compressed RDX crystals (previous paper, this issue). It is proposed that unimolecular decomposition is the primary pathway for RDX decomposition in its early stages and at stresses lower than approximately 10 GPa. This decomposition leads to the generation of broadband emission from 350 to 850 nm. Chemiluminescence from (2)B1 and (2)B2 excited states of NO2 radicals is associated with a major portion of the experimentally observed emission spectrum (>400 nm). The remaining portion (<400 nm) of the emission spectrum primarily results from excited HONO intermediates. It is proposed that for stresses higher than 10 GPa, bimolecular reactions between radical decomposition products and unreacted RDX molecules become the dominant pathway. This radical assisted homolysis pathway is cyclic and leads to the acceleration of decomposition, with increased production of low energy NO2 radicals. These radicals produce emission that is stronger in the long wavelength portion of the spectrum. Finally, a comprehensive chemical decomposition mechanism is put forward that is consistent with the experimental observations of shock-induced emission in RDX crystals. PMID:18642890

Miao, Maosheng; Dreger, Zbigniew A; Patterson, James E; Gupta, Yogendra M

2008-08-14

56

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

ERIC Educational Resources Information Center

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

Kim, Yeon Ha; Stormont, Melissa

2012-01-01

57

Early Stage Soliton Observations in the Sulu Sea* ZACHARY D. TESSLER AND ARNOLD L. GORDON  

E-print Network

Early Stage Soliton Observations in the Sulu Sea* ZACHARY D. TESSLER AND ARNOLD L. GORDON Lamont internal waves, identified as solitons, at three locations. Solitary internal waves have since been of the soliton generation site near Pearl Bank in the Sulu Archipelago. From here, waves propagate toward

Gordon, Arnold L.

58

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

ERIC Educational Resources Information Center

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

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

2006-01-01

59

The Copernicus observations - Interstellar or circumstellar material. [UV spectra of early stars  

NASA Technical Reports Server (NTRS)

It is suggested that the sharp absorption lines observed in the ultraviolet spectra of early-type stars by the Copernicus satellite may be entirely accounted for by the circumstellar material in the H II regions and associated transition zones around the observed stars. If this interpretation is correct, the Copernicus results yield little information on the state of any interstellar (as opposed to circumstellar) gas and, in particular, shed little light on the degree of element depletion in interstellar space.

Steigman, G.; Strittmatter, P. A.; Williams, R. E.

1975-01-01

60

Ulysses radio observations of the heliospheric activity in early June 1991  

NASA Technical Reports Server (NTRS)

The radio receiver of the URAP (Unified Radio and Plasma Wave) experiment on Ulysses has recorded a heliospheric activity particularly intense between late May and early June 1991. Many solar radio emissions of types III and II were observed together with interplanetary (IP) shocks. In the same time, the radio spectrograph ARTEMIS at Nancay (France) observed several intense type II bursts. We investigate the association and/or interaction of these radio emissions, which are remotely observed, with some IP shocks detected in situ, in the context of a Coronal Mass Ejection (CME) induced scenario.

Hoang, S.; Lacombe, C.; Mangeney, A.; Poquerusse, M.; Bougeret, J.-L.; Lengyel-Frey, D.; Macdowall, R. J.; Stone, R. G.

1995-01-01

61

ROSAT PSPC observation of the X-ray faint early-type galaxy NGC5866  

E-print Network

We present the results of the analysis of the ROSAT PSPC pointed observation of the S0 galaxy NGC5866. Previous Einstein observations had revealed that this galaxy has a low X-ray to optical ratio Lx/Lb. Theoretical models of the X-ra emission of early-type galaxies had suggested that in objects of this kind the emission is not dominated by the presence of a hot diffuse gas, but should originate in stellar sources. We discuss the evidence in favor of this hypothesis following from the results of the analysis of the ROSAT PSPC data. The X-ray spectrum shows properties similar to those of the other two low Lx/Lb early-type galaxies observed by ROSAT so far, including the presence of very soft emission. So, these galaxies can be recognized as a group with homogeneous properties, and a more exhaustive picture of the nature of the X-ray emission across the Lx/Lb plane of early-type galaxies can be outlined. We also discuss the importance of rotation in the X-ray emission of S0 galaxies, and suggest that it could explain why on average S0s are less X-ray luminous than ellipticals.

S. Pellegrini

1994-07-03

62

Early GRB Optical and Infrared Afterglow Observations with the 2-m Robotic Liverpool Telescope  

E-print Network

We present the first optical observations of a Gamma Ray Burst (GRB) afterglow using the 2-m robotic Liverpool Telescope (LT), which is owned and operated by Liverpool John Moores University and situated on La Palma. We briefly discuss the capabilities of LT and its suitability for rapid follow-up observations of early optical and infrared GRB light curves. In particular, the combination of aperture, site, instrumentation and rapid response (robotic over-ride mode aided by telescope's rapid slew and fully-opening enclosure) makes the LT ideal for investigating the nature of short bursts, optically-dark bursts, and GRB blast-wave physics in general. We briefly describe the LT's key position in the RoboNet-1.0 network of robotic telescopes. We present the LT observations of GRB041006 and use its gamma-ray properties to predict the time of the break in optical light curve, a prediction consistent with the observations.

A. Gomboc; C. G. Mundell; C. Guidorzi; A. Monfardini; C. J. Mottram; R. Priddey; R. J. Smith; S. Pak; I. A. Steele; N. Tanvir; D. Carter; S. N. Fraser; M. F. Bode; A. M. Newsam; M. Hughes

2005-05-03

63

[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

64

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

65

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

66

Observation of early photons from gamma-ray bursts with the Lomonosov / UFFO-pathfinder  

NASA Astrophysics Data System (ADS)

UFFO-pathfinder is a pioneering space mission to observe the early evolution of Gamma-ray Bursts using a fast slewing strategy. It consists of the Slewing Mirror Telescope, for rapid pointing at UV/optical wavelengths and the UFFO Burst Alert and Trigger Telescope. It has a total weight of ˜ 20 kg and will be launched on-board the Russian Lomonosov satellite at the end of 2015. The instrumental details of UFFO-pathfinder and its performance are discussed briefly here.

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

2014-12-01

67

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

68

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

69

Histological observations of early gonadal development to form asymmetrically in the dwarf gourami Colisa lalia.  

PubMed

The asymmetrical and latitudinal formation of the gonads during early development in the dwarf gourami Colisa lalia was histologically observed using fish reared in laboratory. Hatching larvae obtained 33 hours after spawning possessed primordial germ cells (PGCs), which aggregated to the dorsal surface of the gut. In prolarvae on day 7, the gonadal anlagen were still situated on the dorsal surface of the gut, however, in those on day 10, the left gonadal anläge began to shift leftward, although the coelom did not develop sufficiently. In prolarvae on day 20, the right gonadal anlage also began to move leftward. During this period, the gut developed considerably in the right side of the coelom. On day 25, the developing gonads were located in the interspace of the developing spiral valve intestine. Sex differentiation of gonads appeared to begin by day 25. From those observations, we concluded that asymmetricity of gonads in C. lalia is caused by a limited space of the coelom opened on the left side of the body during the early phase of the formation of gonadal anlagen, which may be accurately determined by the position in which the gut develops. PMID:23215971

Hayakawa, Youichi; Kobayashi, Makito

2012-12-01

70

Early Plate Tectonics Versus Single-Plate Tectonics on Mars: Constraints From Magnetic Field Observations and Crust Evolution  

Microsoft Academic Search

The consequences of an early epoch of plate tectonics on Mars followed by single-plate tectonics with stagnant lid mantle convection on both crust production and magnetic field generation have been studied with parameterized mantle convection models. It is difficult to find models that can reasonably explain both rapid early crust formation, as is required by geological and geophysical observations, and

D. Breuer; T. Spohn

2002-01-01

71

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

PubMed Central

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

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

2013-01-01

72

The Formation History of Early-Type Galaxies: An Observational Perspective  

E-print Network

This talk investigates the formation of early-type galaxies from a deliberately observational view point. I begin by reviewing the conclusions that can be reached by comparing the detailed properties of galaxies in present-day clusters, focusing on the colour-magnitude relation in particular. The overriding picture is one of homogeneity, implying a remarkable uniformity in the formation of these galaxies. This picture contrasts with the increasing activity seen in clusters as a function of redshift, creating an apparent paradox been the obvious diversity of star formation histories in distant cluster galaxies and their uniformity in local systems. A resolution is feasible so long as star formation occurs over an extended epoch. In addition to placing limits on variations in star formation history the existence of a tight `fundamental relations', such as the colour-magnitude relation, can be used to investigate galaxy mergers and to set limits on the degree to which present-day clusters galaxies are built by combining systems of stars formed in smaller units. The final part of this talk turns to early-type galaxies in the field, and tries to apply the same techniques that have been successful in clusters. This is an emerging field in which appropriate data-sets are only just becoming available; however, comparison of the formation histories of galaxies in a wide variety of environments is key to distinguishing between the Classical and Hierarchical models for galaxy formation.

Richard G. Bower; Ale Terlevich; Tadayuki Kodama; Nelson Caldwell

1998-08-28

73

Satellite observed thermospheric impact of solar flares and possible implications for the early Earth  

NASA Astrophysics Data System (ADS)

The evolution of planetary atmospheres depends sensitively on the radiation and particle environment of the planet's hoststar. Atmospheric escape rates are strongly related especially to the soft X-ray (SXR) and extreme and far ultraviolett (EUV and FUV) parts of the solar spectrum. By means of observational data from low Earth orbiting (LEO) satellites it is possible to study the response of the earths thermosphere on enhanced EUV radiation events caused by solar flares. This enables one to estimate exobase temperatures and thermospheric particle densities under different radiation environments. So the flare events can be used as proxies for early Earth studies and for Earth-like atmospheres of potential exoplanets which are exposed to higher stellar EUV fluxes.

Pfleger, M.; Krauss, S.; Hausleitner, W.; Lammer, H.; Fichtinger, B.; Lichtenegger, H. I. M.

2013-09-01

74

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

75

Disseminated intravascular coagulation or acute coagulopathy of trauma shock early after trauma? An observational study  

PubMed Central

Introduction It is debated whether early trauma-induced coagulopathy (TIC) in severely injured patients reflects disseminated intravascular coagulation (DIC) with a fibrinolytic phenotype, acute coagulopathy of trauma shock (ACoTS) or yet other entities. This study investigated the prevalence of overt DIC and ACoTS in trauma patients and characterized these conditions based on their biomarker profiles. Methods An observational study was carried out at a single Level I Trauma Center. Eighty adult trauma patients (?18 years) who met criteria for full trauma team activation and had an arterial cannula inserted were included. Blood was sampled a median of 68 minutes (IQR 48 to 88) post-injury. Data on demography, biochemistry, injury severity score (ISS) and mortality were recorded. Plasma/serum was analyzed for biomarkers reflecting tissue/endothelial cell/glycocalyx damage (histone-complexed DNA fragments, Annexin V, thrombomodulin, syndecan-1), coagulation activation/inhibition (prothrombinfragment 1+2, thrombin/antithrombin-complexes, antithrombin, protein C, activated protein C, endothelial protein C receptor, protein S, tissue factor pathway inhibitor, vWF), factor consumption (fibrinogen, FXIII), fibrinolysis (D-dimer, tissue-type plasminogen activator, plasminogen activator inhibitor-1) and inflammation (interleukin (IL)-6, terminal complement complex (sC5b-9)). Comparison of patients stratified according to the presence or absence of overt DIC (International Society of Thrombosis and Hemostasis (ISTH) criteria) or ACoTS (activated partial thromboplastin time (APTT) and/or international normalized ratio (INR) above normal reference). Results No patients had overt DIC whereas 15% had ACoTS. ACoTS patients had higher ISS, transfusion requirements and mortality (all P < 0.01) and a biomarker profile suggestive of enhanced tissue, endothelial cell and glycocalyx damage and consumption coagulopathy with low protein C, antithrombin, fibrinogen and FXIII levels, hyperfibrinolysis and inflammation (all P < 0.05). Importantly, in non-ACoTS patients, apart from APTT/INR, higher ISS correlated with biomarkers of enhanced tissue, endothelial cell and glycocalyx damage, protein C activation, coagulation factor consumption, hyperfibrinolysis and inflammation, that is, resembling that observed in patients with ACoTS. Conclusions ACoTS and non-ACoTS may represent a continuum of coagulopathy reflecting a progressive early evolutionarily adapted hemostatic response to the trauma hit and both are parts of TIC whereas DIC does not appear to be part of this early response. PMID:22087841

2011-01-01

76

Interactions of tissue and fertilizer nitrogen on decomposition dynamics of lignin-rich conifer litter  

USGS Publications Warehouse

High tissue nitrogen (N) accelerates decomposition of high-quality leaf litter in the early phases of mass loss, but the influence of initial tissue N variation on the decomposition of lignin-rich litter is less resolved. Because environmental changes such as atmospheric N deposition and elevated CO2 can alter tissue N levels within species more rapidly than they alter the species composition of ecosystems, it is important to consider how within-species variation in tissue N may shape litter decomposition and associated N dynamics. Douglas-fir (Pseudotsuga menziesii ) is a widespread lignin-rich conifer that dominates forests of high carbon (C) storage across western North America, and displays wide variation in tissue and litter N that reflects landscape variation in soil N. We collected eight unique Douglas-fir litter sources that spanned a two-fold range in initial N concentrations (0.67–1.31%) with a narrow range of lignin (29–35%), and examined relationships between initial litter chemistry, decomposition, and N dynamics in both ambient and N fertilized plots at four sites over 3 yr. High initial litter N slowed decomposition rates in both early (0.67 yr) and late (3 yr) stages in unfertilized plots. Applications of N fertilizer to litters accelerated early-stage decomposition, but slowed late-stage decomposition, and most strongly affected low-N litters, which equalized decomposition rates across litters regardless of initial N concentrations. Decomposition of N-fertilized litters correlated positively with initial litter manganese (Mn) concentrations, with litter Mn variation reflecting faster turnover of canopy foliage in high N sites, producing younger litterfall with high N and low Mn. Although both internal and external N inhibited decomposition at 3 yr, most litters exhibited net N immobilization, with strongest immobilization in low-N litter and in N-fertilized plots. Our observation for lignin-rich litter that high initial N can slow decomposition yet accelerate N release differs from findings where litter quality variation across species promotes coupled C and N release during decomposition. We suggest reevaluation of ecosystem models and projected global change effects to account for a potential decoupling of ecosystem C and N feedbacks through litter decomposition in lignin-rich conifer forests.

Perakis, Steven S.; Matkins, Joselin J.; Hibbs, David E.

2012-01-01

77

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

78

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

NASA Technical Reports Server (NTRS)

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

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

2003-01-01

79

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

80

Prelexical Decomposition of Compound and Pseudocompound Words  

E-print Network

Previous studies on morphologically complex words suggest early decomposition in the visual word process. In that case, morpheme-like constituents of pseudocompound words (e.g. mushroom) should also be decomposed during ...

Diener, Un So Park

2007-12-12

81

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

SciTech Connect

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

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

2011-05-15

82

ROSAT PSPC observations of 5 X-ray bright early type galaxies.  

NASA Astrophysics Data System (ADS)

We report on the ROSAT PSPC observations of 5 X-ray bright early-type galaxies. Their X-ray morphology is more complex than Einstein data had shown, ranging from the ellipsoidal shape of NGC 533 to the ~200kpc tail of NGC 7619. Hot gas at an average temperature of 0.8-1keV dominates their X-ray emission. The spectral analysis is based on the assumption of a hot thin plasma at cosmic abundances, since the spectral resolution of the PSPC does not allow unambiguous measures of the model parameters (temperatures, low energy cut-off, metal abundance). However, the estimated temperature are not strongly affected by this choice. A temperature distribution of the hot interstellar medium is also derived. Higher temperatures are in some cases observed at larger radii, while the innermost 1' region is cooler in all of the objects studied. Due to the large range in distances however this corresponds to significantly different galaxy radii, from 5kpc in NGC 4649 to 30kpc in NGC 533. The temperature and density distributions derived are used to estimate the total mass of these systems, which span from M_T_~10^12^-10^13^Msun_ and corresponding mass-to-light ratios M/L~10-150 in solar units. Formal errors on the derived masses are estimated to be >25%. Care must be taken in comparing results for different systems, since some of the emission attributed to these objects could suffer from the contribution for the groups and clusters they belong to. Accordingly, our mass estimates could reflect the effect of the cluster/group potential.

Trinchieri, G.; Fabbiano, G.; Kim, D.-W.

1997-02-01

83

Training in early gastric cancer diagnosis improves the detection rate of early gastric cancer: an observational study in china.  

PubMed

Few studies have analyzed the training of endoscopists in the diagnosis of early gastric cancer (EGC). This study assessed whether specific training of endoscopists improves the detection rate of EGC.The rates of detection of EGC by endoscopists at the Digestive Endoscopy Center of the Affiliated Nanfang Hospital of China Southern Medical University between January 2013 and May 2014 were retrospectively analyzed. Because some endoscopists received training in the diagnosis of EGC, beginning in September 2013, the study was divided into 3 time periods: January to September 2013 (period 1), September 2013 to January 2014 (period 2), and January to May 2014 (period 3). The rates of EGC detection during these 3 periods were analyzed.From January 2013 to May 2014, a total of 25,314 gastroscopy examinations were performed at our center, with 48 of these examinations (0.2%) detecting EGCs, accounting for 12.1% (48/396) of the total number of gastric cancers detected. The EGC detection rates by trained endoscopists during periods 1, 2, and 3 were 0.3%, 0.6%, and 1.5%, respectively, accounting for 22.0%, 39.0%, and 60.0%, respectively, of the gastric cancers detected during these time periods. In comparison, the EGC detection rates by untrained endoscopists during periods 1, 2, and 3 were 0.05%, 0.08%, and 0.10%, respectively, accounting for 3.1%, 6.0%, and 5.7%, respectively, of the gastric cancers detected during these times. After training, the detection rate by some trained endoscopists markedly increased from 0.2% during period 1 to 2.3% during period 3. Further, the use of magnifying endoscopy with narrow-band imaging (M-NBI) (odds ratio?=?3.1, 95% confidence interval 2.4-4.1, P?

Zhang, Qiang; Chen, Zhen-Yu; Chen, Chu-di; Liu, Tao; Tang, Xiao-Wei; Ren, Yu-Tang; Huang, Si-Lin; Cui, Xiao-Bing; An, Sheng-Li; Xiao, Bing; Bai, Yang; Liu, Si-de; Jiang, Bo; Zhi, Fa-Chao; Gong, Wei

2015-01-01

84

Herschel and JCMT observations of the early-type dwarf galaxy NGC 205  

NASA Astrophysics Data System (ADS)

We present Herschel dust continuum, James Clerk Maxwell Telescope CO (3-2) observations and a search for [C II] 158 ?m and [O I] 63 ?m spectral line emission for the brightest early-type dwarf satellite of Andromeda, NGC 205. While direct gas measurements [Mg˜ 1.5 × 106 M?, H I+ CO (1-0)] have proven to be inconsistent with theoretical predictions of the current gas reservoir in NGC 205 (>107 M?), we revise the missing interstellar medium mass problem based on new gas mass estimates (CO (3-2), [C II], [O I]) and indirect measurements of the interstellar medium content through dust continuum emission. Based on Herschel observations, covering a wide wavelength range from 70 to 500 ?m, we are able to probe the entire dust content in NGC 205 (? M? at Td˜ 18-22 K) and rule out the presence of a massive cold dust component (? M?, Td˜ 12 K), which was suggested based on millimetre observations from the inner 18.4 arcsec. Assuming a reasonable gas-to-dust ratio of ˜400, the dust mass in NGC 205 translates into a gas mass Mg˜ 4-7 × 106 M?. The non-detection of [O I] and the low L[C II]-to-LCO(1-0) line intensity ratio (˜1850) imply that the molecular gas phase is well traced by CO molecules in NGC 205. We estimate an atomic gas mass of 1.5 × 104 M? associated with the [C II] emitting photodissociation regions in NGC 205. From the partial CO (3-2) map of the northern region in NGC 205, we derive a molecular gas mass of ? M?. Upon comparison with the molecular gas mass estimated from CO (1-0) observations (? M?), we find most of the H2 gas in NGC 205 to be locked in diffuse regions of low density and/or temperature, characteristic for an interstellar medium with little star formation activity. New total gas mass estimates from Herschel dust continuum (4-7 × 106 M?), Herschel [C II] line spectroscopic mapping (1.5 × 104 M?) and James Clerk Maxwell Telescope CO (3-2) observations (7 × 105 M?), including the H I mass (? M?) and a correction for heavier elements, confirm the deficiency of the interstellar medium (gas+dust) in the inner regions of NGC 205, which is predicted to contain at least >107 M? of gas if we assume a reasonable star formation efficiency of 10 per cent and account for the mass return from planetary nebulae. In an attempt to explain the missing interstellar medium mass problem, we claim that efficient supernova feedback capable of expelling gas from the inner, star-forming regions to the outer regions and/or tidal interactions with M31 stripping the gas component from the galaxy provide the best explanation for the removal of a significant amount of gas and dust from NGC 205.

De Looze, I.; Baes, M.; Parkin, T. J.; Wilson, C. D.; Bendo, G. J.; Boquien, M.; Boselli, A.; Cooray, A.; Cormier, D.; Fritz, J.; Galliano, F.; Gear, W.; Gentile, G.; Lebouteiller, V.; Madden, S. C.; Roussel, H.; Sauvage, M.; Smith, M. W. L.; Spinoglio, L.; Verstappen, J.; Young, L.

2012-07-01

85

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

USGS Publications Warehouse

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

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

2006-01-01

86

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. PMID:24109173

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

2013-01-01

87

Simulated NASA Satellite Data Products for the NOAA Integrated Coral Reef Observation Network/Coral Reef Early Warning System  

NASA Technical Reports Server (NTRS)

This RPC (Rapid Prototyping Capability) experiment will demonstrate the use of VIIRS (Visible/Infrared Imager/Radiometer Suite) and LDCM (Landsat Data Continuity Mission) sensor data as significant input to the NOAA (National Oceanic and Atmospheric Administration) ICON/ CREWS (Integrated Coral Reef Observation System/Coral Reef Early Warning System). The project affects the Coastal Management Program Element of the Applied Sciences Program.

Estep, Leland; Spruce, Joseph P.

2007-01-01

88

Early-Time Observations of GRBs afterglow with 2-m Robotic Telescopes  

SciTech Connect

In the era of rapid and accurate localisation of Gamma Ray Bursts by the Swift satellite, high quality early time multi-wavelength light curves, obtained by space and ground-based robotic telescopes, have shown that the standard 'smooth temporal power law decays' typical of late-time afterglow emission can be substantially modified at early times by e.g. energy injection from long-lived central engines, and/or interactions between the ejecta and clumps in the surrounding circumburst medium. Well-sampled optical light curves (covering a wide range in time, brightness and redshift) together with early-time polarimetry provide a powerful probe of the physics of GRBs, their ejecta and their environments. Here we summarise the GRB followup programme being conducted on a network of the world's three largest robotic telescopes that aims to obtain early-time multicolour photometric and polarimetric measurements crucial for the understanding of GRB physics.

Melandri, A.; Mundell, C. G.; Steele, I. A.; Carter, D.; Kobayashi, S.; Bersier, D.; Bode, M. F.; Mottram, C. J.; Smith, R. J. [Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, Birkenhead, CH41 1LD (United Kingdom); Gomboc, A. [Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubiana (Slovenia); Guidorzi, C. [Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, Birkenhead, CH41 1LD (United Kingdom); Physics Department University of Milano-Bicocca, Piazza delle Scienze 3, 20126 Milano (Italy); Monfardini, A. [Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, Birkenhead, CH41 1LD (United Kingdom); CNRS-CRTBT, Avenue des Martyrs 25, 38000 Grenoble (France)

2007-08-21

89

Can the Bump be Observed in the Early Afterglow of GRBS with X-Ray Line Emission Features?  

E-print Network

Extremely powerful emission lines are observed in the X-ray afterglow of several GRBs. The energy contained in the illuminating continuum which is responsible for the line production exceeds 10$^{51}$ erg, much higher than that of the collimated GRBs. It constrains the models which explain the production of X-ray emission lines. In this paper, We argue that this energy can come from a continuous postburst outflow. Focusing on a central engine of highly magnetized millisecond pulsar or magnetar we find that afterglow can be affected by the illuminating continuum, and therefore a distinct achromatic bump may be observed in the early afterglow lightcurves. With the luminosity of the continuous outflow which produces the line emission, we define the upper limit of the time when the bump feature appears. We argue that the reason why the achromatic bumps have not been detected so far is that the bumps should appear at the time too early to be observed.

W. H. Gao; D. M. Wei

2003-11-18

90

A Different View on the Checkerboard? Alterations in Early and Late Visually Evoked EEG Potentials in Asperger Observers  

PubMed Central

Background Asperger Autism is a lifelong psychiatric condition with highly circumscribed interests and routines, problems in social cognition, verbal and nonverbal communication, and also perceptual abnormalities with sensory hypersensitivity. To objectify both lower-level visual and cognitive alterations we looked for differences in visual event-related potentials (EEG) between Asperger observers and matched controls while they observed simple checkerboard stimuli. Methods In a balanced oddball paradigm checkerboards of two checksizes (0.6° and 1.2°) were presented with different frequencies. Participants counted the occurrence times of the rare fine or rare coarse checkerboards in different experimental conditions. We focused on early visual ERP differences as a function of checkerboard size and the classical P3b ERP component as an indicator of cognitive processing. Results We found an early (100–200 ms after stimulus onset) occipital ERP effect of checkerboard size (dominant spatial frequency). This effect was weaker in the Asperger than in the control observers. Further a typical parietal/central oddball-P3b occurred at 500 ms with the rare checkerboards. The P3b showed a right-hemispheric lateralization, which was more prominent in Asperger than in control observers. Discussion The difference in the early occipital ERP effect between the two groups may be a physiological marker of differences in the processing of small visual details in Asperger observers compared to normal controls. The stronger lateralization of the P3b in Asperger observers may indicate a stronger involvement of the right-hemispheric network of bottom-up attention. The lateralization of the P3b signal might be a compensatory consequence of the compromised early checksize effect. Higher-level analytical information processing units may need to compensate for difficulties in low-level signal analysis. PMID:24632708

Kornmeier, Juergen; Wörner, Rike; Riedel, Andreas; Bach, Michael; Tebartz van Elst, Ludger

2014-01-01

91

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

92

Gestalt experiments and inductive observations Konrad Lorenz's early epistemological writings and the methods of classical ethology  

Microsoft Academic Search

During the 1940s Konrad Lorenz formulated his early epistemological views, focusing on the cognitive mechanisms induction and Gestalt perception. After the war he used this philosophical framework to defend the approach of classical ethology against other approaches to animal behavior. The present paper examines the relationship between Lorenz's ethological methodology and his philosophy of science and knowledge. The main aim

Ingo Brigandt

93

Early prenatal ontogeny of central monoamine neurons in the rat: Fluorescence histochemical observations  

Microsoft Academic Search

The early ontogeny of the monoamine neuron systems in the rat brain has been analysed using Falck-Hillarp fluorescence histochemistry. Serial sagittal sections of embryos with a crown rump length between 7 and 13 mm, approximately corresponding to gestational days 12 to 15 were obtained from mothers treated with a monoamine oxidase inhibitor given in order to increase the monoamine levels

Lars Olson; Åke Seiger

1972-01-01

94

Assessment of skeletal changes after post-mortem exposure to fire as an indicator of decomposition stage.  

PubMed

Forensic anthropologists are tasked with interpreting the sequence of events from death to the discovery of a body. Burned bone often evokes questions as to the timing of burning events. The purpose of this study was to assess the progression of thermal damage on bones with advancement in decomposition. Twenty-five pigs in various stages of decomposition (fresh, early, advanced, early and late skeletonisation) were exposed to fire for 30min. The scored heat-related features on bone included colour change (unaltered, charred, calcined), brown and heat borders, heat lines, delineation, greasy bone, joint shielding, predictable and minimal cracking, delamination and heat-induced fractures. Colour changes were scored according to a ranked percentage scale (0-3) and the remaining traits as absent or present (0/1). Kappa statistics was used to evaluate intra- and inter-observer error. Transition analysis was used to formulate probability mass functions [P(X=j|i)] to predict decomposition stage from the scored features of thermal destruction. Nine traits displayed potential to predict decomposition stage from burned remains. An increase in calcined and charred bone occurred synchronously with advancement of decomposition with subsequent decrease in unaltered surfaces. Greasy bone appeared more often in the early/fresh stages (fleshed bone). Heat borders, heat lines, delineation, joint shielding, predictable and minimal cracking are associated with advanced decomposition, when bone remains wet but lacks extensive soft tissue protection. Brown burn/borders, delamination and other heat-induced fractures are associated with early and late skeletonisation, showing that organic composition of bone and percentage of flesh present affect the manner in which it burns. No statistically significant difference was noted among observers for the majority of the traits, indicating that they can be scored reliably. Based on the data analysis, the pattern of heat-induced changes may assist in estimating decomposition stage from unknown, burned remains. PMID:25460103

Keough, N; L'Abbé, E N; Steyn, M; Pretorius, S

2015-01-01

95

The Effects of an Early Observational Experience on Medical Students' Attitudes Toward End-of-Life Care.  

PubMed

End-of-life care is paramount in maintaining the quality of life of the terminally ill, protecting them from unnecessary treatment, and controlling costs incurred in their care. Training doctors to be effective end-of-life caregivers begins in medical school. A survey design was used to collect data from 166 first-year medical students before and after exposure to hospice or palliative care through an early clinical exposure program. Data demonstrated that students had a significant change in attitude scores after the observational experience (P < .05). Providing students with the opportunity to observe and participate in end-of-life care has a positive effect on attitudes toward the care of dying persons. We recommend that direct exposure to end-of-life care practices be incorporated early in the medical school curriculum. PMID:24198062

Wechter, Elizabeth; O'Gorman, Denise Carter; Singh, Mamta K; Spanos, Pete; Daly, Barbara J

2015-02-01

96

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

97

Isothermal decomposition of ?-irradiated samarium acetate  

NASA Astrophysics Data System (ADS)

Isothermal decomposition of un-irradiated and pre-?-irradiated samarium acetate has been investigated at different temperatures between 613 and 633 K. Irradiation was observed to enhance the rate of decomposition without modifying the mechanism of thermal decomposition. Thermal decomposition of samarium acetate has been shown to proceed by two-dimensional phase-boundary reaction both for un-irradiated and pre-?-irradiated samples. The enhancement of the decomposition was found to increase with an increase in the ?-ray dose applied to the sample and may be attributed to an increase in point defects and formation of additional nucleation centers generated in the host lattice. Thermodynamic values of the main decomposition process were calculated and evaluated.

Mahfouz, R. M.; Monshi, M. A. S.; Alshehri, S. M.; Abd El-Salam, N. M.

2000-10-01

98

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

99

UIT Observations of Early-Type Galaxies and Analysis of the FUSE Spectrum of a Subdwarf B Star  

NASA Technical Reports Server (NTRS)

This work covers Ultraviolet Imaging Telescope (UIT) observations of early-type galaxies (155 nm) and Far Ultraviolet Spectroscopic Explorer (FUSE) spectra of a Galactic subdwarf B star (sdB). Early UV space astronomy missions revealed that early-type galaxies harbor a population of stars with effective temperatures greater than that of the main sequence turn-off (about 6,000 K) and UV emission that is very sensitive to characteristics of the stellar population. We present UV (155 nm) surface photometry and UV-B color profiles for 8 E and SO galaxies observed by UIT. Some objects have de Vaucouleurs surface brightness profiles, while others have disk-like profiles, but we find no other evidence for the presence of a disk or young, massive stars. There is a wide range of UV-B color gradients, but there is no correlation with metallicity gradients. SdB stars are the leading candidate UV emitters in old, high metallicity stellar populations (e.g., early-type galaxies). We observed the Galactic sdB star PG0749+658 with FUSE and derived abundances with the aim of constraining models of the heavy element distribution in sdB atmospheres. All of the elements measured are depleted with respect to solar, except for Cr and Mn, which are about solar, and Ni, which is enhanced. This work was supported in part by NASA grants NAG5-700 and NAG5-6403 to the University of Virginia and NAS5-32985 to Johns Hopkins University.

Ohl, Raymond G.; Krebs, Carolyn (Technical Monitor)

2001-01-01

100

Proposed observations of gravity waves from the early Universe via "Millikan oil drops"  

E-print Network

Pairs of Planck-mass drops of superfluid helium coated by electrons (i.e., ``Millikan oil drops''), when levitated in a superconducting magnetic trap, can be efficient quantum transducers between electromagnetic (EM) and gravitational (GR) radiation. This leads to the possibility of a Hertz-like experiment, in which EM waves are converted at the source into GR waves, and then back-converted at the receiver from GR waves back into EM waves. Detection of the gravity-wave analog of the cosmic microwave background using these drops can discriminate between various theories of the early Universe.

R. Y. Chiao

2006-06-28

101

Direct observation of oligomeric species formed in the early stages of amyloid fibril formation using electrospray ionisation mass spectrometry.  

PubMed

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 that may be toxic to cells identified. However, the transient nature of early oligomeric species, combined with their heterogeneity and instability, has precluded detailed analysis to date. Here, we have used electrospray ionisation mass spectrometry (ESI-MS), complemented by analytical ultracentrifugation (AUC) and measurements of thioflavin-T fluorescence, to monitor the early stages of assembly of amyloid-like fibrils formed from human beta-2-microglobulin (beta2m) in vitro. We show that worm-like fibrils that form with nucleation-independent kinetics assemble by a mechanism consistent with monomer addition, with species ranging from monomer to > or = 13-mer being identified directly and uniquely as transient assembly intermediates. By contrast, only monomers, dimers, trimers and tetramers are observed during nucleated growth, which leads to the formation of long straight fibrils. The results highlight the unique power of non-covalent ESI-MS to identify protein assembly intermediates in complex heterogeneous systems and demonstrate its great potential to identify and characterise individual species formed early during amyloid assembly. PMID:17005201

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

2006-11-17

102

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

103

Educative experiences and early childhood science education: A Deweyan perspective on learning to observe  

Microsoft Academic Search

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 interpretive; the data consist of observations, transcripts of science

Elaine V. Howes

2008-01-01

104

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] [Univ. of Florence (Italy); and others

1996-08-23

105

Use of 13C NMR and ftir for elucidation of degradation pathways during natural litter decomposition and composting I. early stage leaf degradation  

USGS Publications Warehouse

Oxidative degradation of plant tissue leads to the formation of natural dissolved organic carbon (DOC) and humus. Infrared (IR) and 13C nuclear magnetic resonance (NMR) spectrometry have been used to elucidate the chemical reactions of the early stages of degradation that give rise to DOC derived from litter and compost. The results of this study indicate that oxidation of the lignin components of plant tissue follows the sequence of O-demethylation, and hydroxylation followed by ring-fission, chain-shortening, and oxidative removal of substituents. Oxidative ring-fission leads to the formation of carboxylic acid groups on the cleaved ends of the rings and, in the process, transforms phenolic groups into aliphatic alcoholic groups. The carbohydrate components are broken down into aliphatic hydroxy acids and aliphatic alcohols.

Wershaw, R.L.; Leenheer, J.A.; Kennedy, K.R.; Noyes, T.I.

1996-01-01

106

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

107

SOAR Remote Observing: Tactics and Early Results Gerald Cecil1a  

E-print Network

compression, remote observing, LabVIEW, SOAR 1. INTRODUCTION As described previously1 , SOAR is deploying of IP connectivity required to support reliably projects that incorporate intensive video conferencing

Cecil, Gerald

108

FUSE Observations of three Early-type, Double-lined Spectroscopic Binaries in the Magellanic Clouds  

Microsoft Academic Search

Initial Far Ultraviolet Spectroscopic Explorer (FUSE) observations of Hodge 53-47, an O4IIIf + O6V (16 Msun + 26 Msun) massive binary in the SMC and HV2241, an O7 V + O8 V-III (36 Msun + 18 Msun) massive binary in the LMC are presented. A comparison was made with FUSE archival observations on SK-67 105 (48 Msun + 31 Msun)

R. C. Iping; D. Gies; G. Sonneborn; L. Kaper

2008-01-01

109

TV observations of meteors from the Aquarius region in early August  

NASA Astrophysics Data System (ADS)

Single-station TV observations in Aquarius near the radiant of the Aquarid meteor complex were carried out during three nights from August 1 to August 5, 2003. The observations continued at other localities during the night of August 12/13. Individual radiants of single meteors from were calculated from angular velocities. The associations to active shower were analysed. The method and result are discussed.

Zimnikoval, P.

110

Risk of Trastuzumab-Related Cardiotoxicity in Early Breast Cancer Patients: A Prospective Observational Study  

PubMed Central

Purpose In the present study, we investigated the incidence of cardiotoxicity within 5 years of trastuzumab treatment and evaluated potential risk factors in clinical practice. Methods The study cohort included 415 patients diagnosed with early breast cancer (EBC). Cardiotoxicity incidence was evaluated in patients receiving trastuzumab and those who did not. Multivariate Cox proportional hazards regression models were used to estimate hazard ratios and 95% confidence intervals of potential risk factors for trastuzumab-related cardiotoxicity after appropriate adjustments. Results Incidence of cardiotoxicity in patients treated with trastuzumab was significantly higher than that in controls (23.7% vs. 10.8%, p<0.001). This result was adjusted for factors that might increase the risk of cardiotoxicity, such as history of coronary artery diseases or the use of anthracyclines for more than four cycles. Conclusion Our findings indicated that treatment with trastuzumab was strongly associated with cardiotoxicity in EBC patients. PMID:25548585

Xue, Jian; Jiang, Zefei; Qi, Fan; Lv, Shuanghong; Zhang, Shaohua; Wang, Tao

2014-01-01

111

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

PubMed Central

Triggered hydrogelation of MAX1 peptide, (VK)4-VDPPT-(KV)4-NH2, proceeds through peptide intramolecular folding into ?-hairpins and concomitant self-assembly into branched clusters of well-defined (uniform, 3 nm cross section), semiflexible, ?-sheet-rich nanofibrils. Cryogenic transmission electron microscopy indicates that dangling fibrils extend from one growing cluster to another and lead to early, intercluster communication in solution. At the apparent percolation threshold, the dynamic shear modulus measured by oscillatory rheology (G?(?), G?(?) ? ?n) and the field-intensity autocorrelation function measured by dynamic light scattering (g1(?) ? ?-??) show power-law behavior with comparable critical dynamic exponents (n ? 0.47 and ?? ? 0.45). Finite interpenetration of percolating clusters with smaller clusters, along with permanent intercluster entanglements, increase the network rigidity. The self-assembly of MAX1 peptide was compared and contrasted with the assembly of other biopolymeric networks in literature. PMID:19169385

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

2009-01-01

112

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

PubMed

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

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

2014-08-01

113

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

NASA Technical Reports Server (NTRS)

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

Jones, Barbara

1997-01-01

114

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

2012-04-12

115

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

116

An Observational Study of Early Heterosexual Interaction at Middle School Dances  

ERIC Educational Resources Information Center

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

Pellegrini, Anthony D.; Long, Jeffery D.

2007-01-01

117

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

NASA Astrophysics Data System (ADS)

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

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

2013-01-01

118

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

119

White Noise from Dark Matter: 21 cm Observations of Early Baryon Collapse  

E-print Network

In concordance cosmology, dark matter density perturbations generated by inflation lead to nonlinear, virialized minihalos, into which baryons collapse at redshift $z \\sim 20$. We survey here novel baryon evolution produced by a modification of the power spectrum from white noise density perturbations at scales below $k \\sim 10 h {Mpc}^{-1}$ (the smallest scales currently measured with the Lyman-$\\alpha$ forest). Exotic dark matter dynamics, such as would arise from scalar dark matter with a late phase transition (similar to an axion, but with lower mass), create such an amplification of small scale power. The dark matter produced in such a phase transition collapses into minihalos, with a size given by the dark matter mass within the horizon at the phase transition. If the mass of the initial minihalos is larger than $\\sim 10^{-3} M_\\odot$, the modified power spectrum is found to cause widespread baryon collapse earlier than standard $\\Lambda$CDM, leading to earlier gas heating. It also results in higher spin temperature of the baryons in the 21 cm line relative to $\\Lambda$CDM at redshifts $z > 20$ if the mass of the minihalo is larger than $1 M_\\odot$. It is estimated that experiments probing 21 cm radiation at high redshift will contribute a significant constraint on dark matter models of this type for initial minihalos larger than $\\sim 10 M_\\odot$. Early experiments reaching to $z\\approx 15$ will constrain minihalos down to $\\sim 10^3 M_\\odot$.

Kathryn M. Zurek; Craig J. Hogan

2007-03-26

120

Copernicus observations of the N v resonance doublet in 53 early-type stars  

NASA Technical Reports Server (NTRS)

UV spectra in the wavelength interval 1170-1270 A are presented for 53 early-type stars ranging in spectral type from O6.5 V to B2.5 IV. The sample includes four Wolf-Rayet stars, seven known Oe-Be stars, and six galactic halo OB stars. A qualitative analysis of the stellar N v doublet reveals that: (1) N v is present in all stars hotter and more luminous than type B0 for the main sequence, B1 for giants, and B2 for supergiants; (2) shell components of N v and an unidentified absorption feature at 1230 A are present in about half of the stars; (3) the column density of N v is well correlated with bolometric luminosity over the spectral range O6 to B2; and (4) the ratio of emission to absorption equivalent width is a factor of 2 smaller in the main sequence stars than in supergiants, which suggests that the wind structure changes as a star evolves. For several stars, this ratio is too small to be explained by traditional wind models.

Abbott, D. C.; Bohlin, R. C.; Savage, B. D.

1982-01-01

121

Early Prediction of Intensive Care Unit–Acquired Weakness Using Easily Available Parameters: A Prospective Observational Study  

PubMed Central

Introduction An early diagnosis of Intensive Care Unit–acquired weakness (ICU–AW) using muscle strength assessment is not possible in most critically ill patients. We hypothesized that development of ICU–AW can be predicted reliably two days after ICU admission, using patient characteristics, early available clinical parameters, laboratory results and use of medication as parameters. Methods Newly admitted ICU patients mechanically ventilated ?2 days were included in this prospective observational cohort study. Manual muscle strength was measured according to the Medical Research Council (MRC) scale, when patients were awake and attentive. ICU–AW was defined as an average MRC score <4. A prediction model was developed by selecting predictors from an a–priori defined set of candidate predictors, based on known risk factors. Discriminative performance of the prediction model was evaluated, validated internally and compared to the APACHE IV and SOFA score. Results Of 212 included patients, 103 developed ICU–AW. Highest lactate levels, treatment with any aminoglycoside in the first two days after admission and age were selected as predictors. The area under the receiver operating characteristic curve of the prediction model was 0.71 after internal validation. The new prediction model improved discrimination compared to the APACHE IV and the SOFA score. Conclusion The new early prediction model for ICU–AW using a set of 3 easily available parameters has fair discriminative performance. This model needs external validation. PMID:25347675

Wieske, Luuk; Witteveen, Esther; Verhamme, Camiel; Dettling-Ihnenfeldt, Daniela S.; van der Schaaf, Marike; Schultz, Marcus J.; van Schaik, Ivo N.; Horn, Janneke

2014-01-01

122

Observations of Photospheric Vortical Motions During the Early Stage of Filament Eruption  

NASA Astrophysics Data System (ADS)

Solar filaments/prominences exhibit rotational motion during different phases of their evolution from their formation to eruption. We have observed the rotational/vortical motion in the photosphere near the ends of ten filaments during their initial phase of eruption, at the onset of the fast rise phase. All the filaments were associated with active regions. The photospheric vortical motions we observed lasted for 4 - 20 minutes. In the vicinity of the conjugate ends of the filament the direction of rotation was opposite, except for two cases, where rotational motion was observed at only one end point. The sudden onset of a large photospheric vortex motion could have played a role in destabilizing the filament by transporting axial flux into the activated filament thereby increasing the outward magnetic pressure in it. The outward magnetic pressure may have pushed the filament/flux rope to the height where the torus instability criterion was satisfied, and hence it could have caused the filament instability and eruption.

Dhara, Sajal Kumar; Ravindra, B.; Banyal, Ravinder Kumar

2014-12-01

123

Observations of Photospheric Vortical Motions During the Early Stage of Filament Eruption  

E-print Network

Solar filaments/prominences exhibit rotational motion during different phases of their evolution from their formation to eruption. We have observed the rotational/vortical motion in the photosphere near the ends of ten filaments during their initial phase of eruption, at the onset of the fast rise phase. All the filaments were associated with active regions. The photospheric vortical motions we observed lasted for 4--20 minutes. In the vicinity of the conjugate ends of the filament the direction of rotation was opposite, except for two cases, where rotational motion was observed at only one end point. The sudden onset of a large photospheric vortex motion could have played a role in destabilizing the filament by transporting axial flux into the activated filament thereby increasing the outward magnetic pressure in it. The outward magnetic pressure may have pushed the filament/flux rope to the height where the torus instability criterion was satisfied, and hence it could have caused the filament instability an...

Dhara, Sajal Kumar; Banyal, Ravinder Kumar

2014-01-01

124

Early Additional Immune-Modulators for Mycoplasma pneumoniae Pneumonia in Children: An Observation Study  

PubMed Central

Background Mycoplasma pneumoniae (MP) pneumonia is a self-limiting disease, but some patients complain of progressive pneumonia, despite of appropriate antibiotic treatment. We aimed to introduce the role of immune-modulators (corticosteroid and/or intravenous immunoglobulin, IVIG) treatment for childhood MP pneumonia based on previous our experiences. Materials and Methods A retrospective case series analysis for 183 children with MP pneumonia was performed. MP pneumonia patients were diagnosed by two Immunoglobulin M (IgM) tests: the micro-particle agglutination method (?1:40) and the cold agglutination test (?1:4), and were examined twice at the initial admission and at discharge. Among 183 MP pneumonia patients, 90 patients with persistent fever for over 48 hours after admission or those with severe respiratory symptoms and signs received additional prednisolone (82 patients, 1 mg/kg/day) or intravenous methylprednisolone (8 patients, 5-10 mg/kg/day) with antibiotics. Four patients with aggravated clinical symptoms and chest radiographic findings after corticosteroid treatment received IVIG (1 g/kg/day, 1-2 doses). Results Mean age of 183 patients was 5.5 ± 3.2 years (6 months-15 years), and the male: female ratio was 1.1:1 (96:87). Fifty-seven patients (31%) were seroconverters and 126 seropositive patients showed increased diagnostic IgM antibody titres during admission (over 4 folds). The majority of the patients who received corticosteroids (86/90 cases) showed rapid defervescence within 48 hours with improved clinical symptoms, regardless of the used antibiotics. Also, 4 patients who received additional IVIG improved both clinically and radiographically within 2 days without adverse reaction. Conclusions In the era of macrolide-resistant MP strains, early additional immune-modulator therapy with antibiotics might prevent from the disease progression and reduce the disease morbidity without adverse reaction.

Lee, Sung-Churl; Rhim, Jung-Woo; Shin, Myung-Seok; Kang, Jin-Han

2014-01-01

125

Early resuscitation intensity as a surrogate for bleeding severity and early mortality in the PRospective, Observational, Multicenter, Major Trauma Transfusion (PROMMTT) Study  

PubMed Central

Background The classic definition of MT, ?10 units red blood cells (RBCs) in 24 hours, has never been demonstrated as a valid surrogate for severe hemorrhage and can introduce survival bias. In addition, the definition fails to capture other products that the clinician may have immediately available during the initial resuscitation. Assuming that units of resuscitative fluids reflect patient illness, our objective was to identify a rate of resuscitation intensity (RI) that could serve as an early surrogate of sickness for patients with substantial bleeding post-injury. Methods Adult patients surviving at least 30 minutes post-admission and receiving ?1 RBC within 6 hours of admission from ten US Level 1 trauma centers were enrolled in the PRospective Observational Multicenter Major Trauma Transfusion study. Total fluid units were calculated as the sum of the number of crystalloid units (1 L=1 unit), colloids (0.5 L=1 unit) and blood products (1 RBC=1 unit, 1 plasma=1 unit, 6 pack platelets=1 unit). Univariable and multivariable logistic regressions were used to evaluate associations between RI and 6-hour mortality, adjusting for age, center, penetrating injury, weighted Revised Trauma Score, and Injury Severity Score. Results 1096 eligible patients received resuscitative fluids within 30 minutes, including 620 transfused with blood products. Despite varying products utilized, the total fluid RI was similar across all sites (3.2±2.5 units). Patients who received ?4 units of any resuscitative fluid had a 6-hour mortality rate of 14.4% vs. 4.5% in patients who received <4 units. The adjusted odds ratio of 6-hour mortality for patients receiving ?4 units within 30 minutes was 2.1 (95% Confidence Interval: 1.2–3.5). Conclusions Resuscitation with ?4 units of any fluid was significantly associated with 6-hour mortality. This study suggests that early RI regardless of fluid type can be used as a surrogate for sickness and mortality in severely bleeding patients. Level of Evidence PROMMTT is a prospective observational study, Level II. PMID:23778506

Rahbar, Elaheh; Fox, Erin E.; del Junco, Deborah J.; Harvin, John A.; Holcomb, John B.; Wade, Charles E.; Schreiber, Martin A.; Rahbar, Mohammad H.; Bulger, Eileen M.; Phelan, Herb A.; Brasel, Karen J.; Alarcon, Louis H.; Myers, John G.; Cohen, Mitchell J.; Muskat, Peter; Cotton, Bryan A.

2013-01-01

126

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

127

The accelerations of the earth and moon from early astronomical observations  

NASA Technical Reports Server (NTRS)

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 the events, and thereby made estimates of the earth acceleration and lunar acceleration. The basic conclusion is that the lunar acceleration and both tidal and nontidal earth accelerations have been essentially constant during the period from 1375 B.C. to the present.

Muller, P. M.; Stephenson, F. R.

1975-01-01

128

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

NASA Technical Reports Server (NTRS)

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

1990-01-01

129

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

USGS Publications Warehouse

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

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

2010-01-01

130

BIMA Observations of Early Stages of High-Mass Star Formation  

NASA Astrophysics Data System (ADS)

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

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

1999-10-01

131

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

132

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

NASA Technical Reports Server (NTRS)

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

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

2010-01-01

133

Early Observations and Analysis of the Type Ia SN 2014J in M82  

NASA Astrophysics Data System (ADS)

We present optical and near infrared (NIR) observations of the nearby Type Ia SN 2014J. Seventeen optical and 23 NIR spectra were obtained from 10 days before (–10d) to 10 days after (+10d) the time of maximum B-band brightness. The relative strengths of absorption features and their patterns of development can be compared at one day intervals throughout most of this period. Carbon is not detected in the optical spectra, but we identify C I ?1.0693 in the NIR spectra. Mg II lines with high oscillator strengths have higher initial velocities than other Mg II lines. We show that the velocity differences can be explained by differences in optical depths due to oscillator strengths. The spectra of SN 2014J show that it is a normal SN Ia, but many parameters are near the boundaries between normal and high-velocity subclasses. The velocities for O I, Mg II, Si II, S II, Ca II, and Fe II suggest that SN 2014J has a layered structure with little or no mixing. That result is consistent with the delayed detonation explosion models. We also report photometric observations, obtained from –10d to +29d, in the UBVRIJH and Ks bands. The template fitting package SNooPy is used to interpret the light curves and to derive photometric parameters. Using RV = 1.46, which is consistent with previous studies, SNooPy finds that AV = 1.80 for E(B – V)host = 1.23 ± 0.06 mag. The maximum B-band brightness of –19.19 ± 0.10 mag was reached on February 1.74 UT ± 0.13 days and the supernova has a decline parameter, ?m 15, of 1.12 ± 0.02 mag.

Marion, G. H.; Sand, D. J.; Hsiao, E. Y.; Banerjee, D. P. K.; Valenti, S.; Stritzinger, M. D.; Vinkó, J.; Joshi, V.; Venkataraman, V.; Ashok, N. M.; Amanullah, R.; Binzel, R. P.; Bochanski, J. J.; Bryngelson, G. L.; Burns, C. R.; Drozdov, D.; Fieber-Beyer, S. K.; Graham, M. L.; Howell, D. A.; Johansson, J.; Kirshner, R. P.; Milne, P. A.; Parrent, J.; Silverman, J. M.; Vervack, R. J., Jr.; Wheeler, J. C.

2015-01-01

134

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

135

Estimates for Lorentz Factors of Gamma-Ray Bursts from Early Optical Afterglow Observations  

NASA Astrophysics Data System (ADS)

The peak time of optical afterglow may be used as a proxy to constrain the Lorentz factor ? of the gamma-ray burst (GRB) ejecta. We revisit this method by including bursts with optical observations that started when the afterglow flux was already decaying; these bursts can provide useful lower limits on ?. Combining all analyzed bursts in our sample, we find that the previously reported correlation between ? and the burst luminosity L ? does not hold. However, the data clearly show a lower bound ?min that increases with L ?. We suggest an explanation for this feature: explosions with large jet luminosities and ? < ?min suffer strong adiabatic cooling before their radiation is released at the photosphere; they produce weak bursts, barely detectable with present instruments. To test this explanation, we examine the effect of adiabatic cooling on the GRB location in the L ? - ? plane using a Monte Carlo simulation of the GRB population. Our results predict detectable on-axis "orphan" afterglows. We also derive upper limits on the density of the ambient medium that decelerates the explosion ejecta. We find that the density in many cases is smaller than expected for stellar winds from normal Wolf-Rayet progenitors. The burst progenitors may be peculiar massive stars with weaker winds, or there might exist a mechanism that reduces the stellar wind a few years before the explosion.

Hascoët, Romain; Beloborodov, Andrei M.; Daigne, Frédéric; Mochkovitch, Robert

2014-02-01

136

ROSAT PSPC observations of two X-ray-faint early-type galaxies: NGC 4365 and NGC 4382  

NASA Technical Reports Server (NTRS)

We present the results of ROSAT Positive Sensitive Proportional Counter (PSPC) observations of the two early-type galaxies NGC 4365 and NGC 4382. These galaxies are among those observed with Einstein to have the lowest X-ray to optical flux ratios of early-type galaxies. The PSCP data show that for radii r greater than 50 arcsec the radial distributions of the X-ray surface brightness are consistent with the optical distributions of King (1978). We also find that these galaxies have X-ray spectra significantly different from those observed in X-ray-bright ellipticals, with a relative excess of counts detected in the softest spectral channels. This confirms earlier Einstein results. The characteristics of the ROSAT PSPC do not allow us to discriminate between possible spectral models. If we adopt a two-component thermal model on the grounds of physical plausibility, we find that the spectral data can be fitted with a very soft optically thin component, with kT approximately 0.2 keV, and a hard component with kT greater than (1.0-1.5) keV. The hard component has a luminosity consistent with that expected from the integrated emission of a population of low mass-X-ray binaries in these galaxies; the nature of the very soft component is more speculative. Candidates include the coronal emission of late-type stars, supersoft X-ray sources, RS CVn, and perhaps a hot Interstellar Medium (ISM). Alternatively, the spectal data may be fitted with a 0.6-1 keV bremsstrahlung spectrum (expontential plus Gaunt), and may suggest the presence of a totally new population of X-ray sources.

Fabbiano, G.; Kim, D.-W.; Trinchieri, G.

1994-01-01

137

Curvature perturbations in the early universe: Theoretical models and observational tests  

NASA Astrophysics Data System (ADS)

A very general prediction of inflation is that the power spectrum of density perturbations is characterized by a spectral index ns which is scale independent and approximately equal to unity. Drawing from the potential reconstruction method and adopting the slow-roll parameter expansion technique, we derive all possible single field inflationary potentials that would lead to a scale invariant density spectral index, consistent with current observations. In the process, a new method to determine the functional form of the inflationary potential in the slow roll approximation is devised, based on the reparametrization of the field dynamics with respect to the slow roll parameter epsilon which also allowed to show that under the assumptions made the investigation proved to be exhaustive and that no other solutions are available. Next, we focus on the fact that there exist a large class of inflationary models currently ruled out because the predicted production of curvature perturbations during the slow-roll stage results exponentially suppressed. We investigate whether an alternative mechanism for the generation of curvature perturbations can be devised for such a class of models. In the process, it is shown that it is sufficient for the inflationary potential to exhibit a broken symmetry to successfully convert isocurvature perturbations, which are excited during the slow-roll stage, into curvature perturbations thanks to an inhomogeneous decay stage. This conclusion is general, requiring as a sufficient condition only the fact that the inflation potential is characterized by a broken symmetry. Finally, we show that the perturbations thus produced are generally characterized by a non-negligible degree of non-gaussianity, which then provides a clear experimental signature for experimental detection or rejection.

Vallinotto, Alberto

138

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

USGS Publications Warehouse

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

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

1999-01-01

139

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

140

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

141

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

NASA Technical Reports Server (NTRS)

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. A qualitative explanation for this effect can be derived from IMP observations, which show that the amplitude of the stream structure at 1 AU increased monotonically in late 1993, concurrent with major secular evolution in the corona. The reduction in period, then, amounts to a doppler shift due to the progressive overtaking of successively faster streams in the sequence. Attempts to model this process quantitatively with 1-D dynamic simulations falter on three accounts: (1) the reduction in period is overestimated, (2) the simulation predicts many more fronts surviving to 43 AU than are observed by Voyager; (3) the density variations are much too large. It is argued that inclusion of the 3-D geometry in the simulation would resolve most all these shortcomings. Using a series of calculations executed with 1-D, 2-D, and 3-D MHD models of hypothetical tilted-dipole flows, we show that: (1) the radial propagation velocities of 3-D fronts are less than those of 1-D or 2-D fronts, owing to the tilt of (and increased shearing across) the interaction surfaces hence the overtaking rate of successive streams is reduced; (2) in a tilted-dipole geometry, the reverse fronts should largely disappear from the equatorial plane by 43 AU, effectively halving the number of fronts to be observed (see companion paper on predominance of forward fronts at Voyager); and (3) the density enhancements would be much smaller than predicted by a 1-D model.

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

1995-01-01

142

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

E-print Network

We combine new high sensitivity ultraviolet (UV) imaging from the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST) with existing deep HST/Advanced Camera for Surveys (ACS) optical images from the Great Observatories Origins Deep Survey (GOODS) program to identify UV-dropouts, which are Lyman break galaxy (LBG) candidates at z~1-3. These new HST/WFC3 observations were taken over 50 sq.arcmin in the GOODS-South field as a part of the Early Release Science program. The uniqueness of these new UV data is that they are observed in 3 UV/optical (WFC3 UVIS) channel filters (F225W, F275W and F336W), which allows us to identify three different sets of UV-dropout samples. We apply Lyman break dropout selection criteria to identify F225W-, F275W- and F336W-dropouts, which are z~1.7, 2.1 and 2.7 LBG candidates, respectively. We use multi-wavelength imaging combined with available spectroscopic and photometric redshifts to carefully access the validity of our UV-dropout candidates. Our results are as follows...

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

2010-01-01

143

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

144

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

NASA Astrophysics Data System (ADS)

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

Pérot, K.; Urban, J.; Murtagh, D. P.

2014-02-01

145

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

NASA Astrophysics Data System (ADS)

The middle atmosphere was affected by an exceptionally strong midwinter stratospheric sudden warming (SSW) during the Arctic winter 2012/2013. These unusual meteorological conditions led to a breakdown of the polar vortex, followed by the reformation of a strong upper stratospheric vortex associated with particularly efficient descent of air. Measurements by the submillimetre radiometer (SMR), on board the Odin satellite, show that very large amounts of nitric oxide (NO), produced by energetic particle precipitation (EPP) in the mesosphere/lower thermosphere (MLT), could thus enter the polar stratosphere in early 2013. The mechanism referring to the downward transport of EPP-generated NOx during winter is generally called the EPP indirect effect. SMR observed up to 20 times more NO in the upper stratosphere than the average NO measured at the same latitude, pressure and time during three previous winters where no mixing between mesospheric and stratospheric air was noticeable. This event turned out to be the strongest in the aeronomy-only period of SMR (2007-present). Our study is based on a comparison with the Arctic winter 2008/2009, when a similar situation was observed. This outstanding situation is the result of the combination of a relatively high geomagnetic activity and an unusually high dynamical activity, which makes this case a prime example to study the EPP impacts on the atmospheric composition.

Pérot, K.; Urban, J.; Murtagh, D. P.

2014-08-01

146

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.

2011-10-01

147

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

SciTech Connect

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 just east of the field. Observations of birds between March and June 1982 revealed that (1) the natural avifauna of the field has been altered, although the area is still used for feeding by some icterids (larks, blackbirds) and aerial insectivores (swallows, swifts); (2) of 15 bird casualties ascribable to the presence and/or operation of Solar One, 12 followed collisions with heliostats, three resulted from incineration in heliostat beams; (3) the central receiver tower does not appear to be a source of mortality. Numbers of rodents (particularly kangaroo rats) trapped in areas downwind of the site declined steadily between 1978 and 1982 in areas both clost to the field and as far east as 600 m from the fence. The most likely interpretation of these changes is a reduction in reproductivity and/or early survival caused by four consecutive years (1978, 1979, 1980, 1981) of suboptimal autumn rainfall. Micrometeorological measurements in areas downwind of Solar One showed small effects on air temperatures (<0.5/sup 0/C), wind speeds (<0.4 m/sec), and evaporation rates (<1.5 ml/hr).Effects were detected only in areas 100 to 190 m from the east perimeter fence. Because these differences are so small, relative to natural heterogeneities, the effects of Solar One on rates of evaporation, air temperatures and wind speed will not affect the downwind biological community. The relavance of these findings to construction of a larger solar thermal power plant (e.g., Solar 100) are considered.

Turner, F.B. (ed.)

1982-11-01

148

Serum Adhesion Molecule Levels as Prognostic Markers in Patients with Early Systemic Sclerosis: A Multicentre, Prospective, Observational Study  

PubMed Central

Objective To assess the utility of circulating adhesion molecule levels as a prognostic indicator of disease progression in systemic sclerosis (SSc) patients with early onset disease. Methods Ninety-two Japanese patients with early onset SSc presenting with diffuse skin sclerosis and/or interstitial lung disease were registered in a multicentre, observational study. Concentrations of intercellular adhesion molecule (ICAM) ?1, E-selectin, L-selectin, and P-selectin in serum samples from all patients were measured by enzyme-linked immunosorbent asssay (ELISA). In 39 patients, adhesion molecule levels were measured each year for four years. The ability of baseline adhesion molecule levels to predict subsequent progression and severity in clinical and laboratory features were evaluated statistically. Results At their first visit, serum levels of ICAM-1, E-selection, P-selectin were significantly elevated and serum L-selectin levels were significantly reduced in patients with SSc compared with healthy controls. Overall, serum ICAM-1 levels at each time point were significantly inversely associated with the %vital capacity (VC) of the same time and subsequent years by univariate analysis. The initial serum ICAM-1 levels were significantly inversely associated with the %VC at the fourth year by multiple regression analysis. The initial serum P-selectin levels were significantly associated with the health assessment questionnaire disability index (HAQ-DI) at the fourth year by multiple regression analysis. Initial adhesion molecule levels were not significantly associated with other clinical features including skin thickness score. Baseline adhesion molecule levels were not significantly associated with subsequent rate of change of clinical parameters. Conclusion In patients with SSc, serum levels of ICAM-1 and P-selectin may serve as prognostic indicators of respiratory dysfunction and physical disability, respectively. Further longitudinal studies of larger populations are needed to confirm these findings. PMID:24516598

Hasegawa, Minoru; Asano, Yoshihide; Endo, Hirahito; Fujimoto, Manabu; Goto, Daisuke; Ihn, Hironobu; Inoue, Katsumi; Ishikawa, Osamu; Kawaguchi, Yasushi; Kuwana, Masataka; Ogawa, Fumihide; Takahashi, Hiroki; Tanaka, Sumiaki; Sato, Shinichi; Takehara, Kazuhiko

2014-01-01

149

Wavelet frequency decomposition method  

NASA Astrophysics Data System (ADS)

A wavelet variation of the frequency decomposition multigrid method of Hackbusch is presented. The perfect reconstruction property of the wavelet system enable us to perform the convergence analysis of the frequency decomposition method. Some applications of this method are also presented.

Rieder, Andreas; Wells, Raymond O., Jr.; Zhou, Xiaodong

1994-03-01

150

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

151

Thermal Decomposition Mechanism of Butyraldehyde  

NASA Astrophysics Data System (ADS)

The thermal decomposition of butyraldehyde, CH_3CH_2CH_2C(O)H, has been studied in a resistively heated SiC tubular reactor. Products of pyrolysis were identified via matrix-isolation FTIR spectroscopy and photoionization mass spectrometry in separate experiments. Carbon monoxide, ethene, acetylene, water and ethylketene were among the products detected. To unravel the mechanism of decomposition, pyrolysis of a partially deuterated sample of butyraldehyde was studied. Also, the concentration of butyraldehyde in the carrier gas was varied in experiments to determine the presence of bimolecular reactions. The results of these experiments can be compared to the dissociation pathways observed in similar aldehydes and are relevant to the processing of biomass, foods, and tobacco.

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

2013-06-01

152

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

SciTech Connect

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

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

2010-09-10

153

Low-Mass X-ray Binaries and Globular Clusters in Early-Type Galaxies. I. Chandra Observations  

E-print Network

We present a Chandra survey of LMXBs in 24 early-type galaxies. Correcting for detection incompleteness, the X-ray luminosity function (XLF) of each galaxy is consistent with a powerlaw with negative logarithmic differential slope, beta~2.0. However, beta strongly correlates with incompleteness, indicating the XLF flattens at low-Lx. The composite XLF is well-fitted by a powerlaw with a break at (1.8^{+0.37}_{-0.32})\\times 10^{38} erg/s and beta=0.99+/-0.15 and 2.82^{+0.30}_{-0.24} below and above it, respectively. The break is close to the Eddington limit for a 1.4Msun neutron-star, but the XLF shape rules out its representing the division between neutron-star and black-hole systems. Although the XLFs are similar, we find evidence of some variation between galaxies. The high-Lz XLF slope does not correlate with age, but may correlate with [alpha/Fe]. Matching the LMXBs with globular clusters (GCs) identified in HST observations of 19 of the galaxies, we find the probability a GC hosts an LMXB is proportional...

Humphrey, P J; Humphrey, Philip J.; Buote, David A.

2006-01-01

154

INDISCRIMINATE BEHAVIOR OBSERVED IN THE STRANGE SITUATION AMONG INSTITUTIONALIZED TODDLERS: RELATIONS TO CAREGIVER REPORT AND TO EARLY FAMILY RISK  

PubMed Central

Socially disinhibited or indiscriminate behavior (IB) has traditionally been investigated using caregiver reports. More recently, an observational measure based on the Strange Situation Procedure (M. Ainsworth, M. Blehar, E. Waters, & S. Wall, 1978), the Rating of Infant and Stranger Engagement (RISE; C. Riley, A. Atlas-Corbett, & K. Lyons-Ruth, 2005), was validated in home-reared at-risk children. The present study aimed to validate the RISE in an institutionally reared sample using the caregiver report, to assess whether IB assessed with the RISE was elevated among the institutionalized children, and to explore potential risk factors associated with IB. The study was conducted among 74 institutionalized toddlers aged 11 to 30 months. Sociodemographic questionnaires were used to assess pre-admission experiences, and aspects of institutional placement were coded from the children’s files in the institution and staff’s report. Institutionalized children displayed high frequencies of IB as assessed on the RISE, and this instrument was validated against caregiver report. Pre-admission experiences of the institutionalized children in their biological families—namely, prenatal risk and maternal emotional neglect risk—predicted IB. Results suggest that the RISE is adequate to use among institutionally reared toddlers and point to aspects of the early familial environment that may be implicated in IB.

Oliveira, Paula S.; Soares, Isabel; Martins, Carla; Silva, Joana R.; Marques, Sofia; Baptista, Joana; Lyons-Ruth, Karlen

2014-01-01

155

Decomposition studies of tertiarybutyldimethylantimony  

NASA Astrophysics Data System (ADS)

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 vapor pressure is 7.3 Torr at 23° C. The 50% decomposition temperature is 300° C for both He and D 2 ambients in a flow tube reactor with a residence time of approximately 3.2 sec at 300° C. The decomposition products are primarily C4H10, C4H8, and TMSb in both ambients. The overall decomposition reaction is first order. The decomposition mechanism is believed to be homolysis followed by recombination and disproportionation reactions for C4H9 and (CH3)2Sb groups. Added trimethylgallium (TMGa) has no measurable effect on either the pyrolysis rate or the products. Apparently, TMGa and TBDMSb do not interact during pyrolysis nor do they form a room temperature adduct. No room temperature adduct between TMGa and TBDMSb was formed. It is believed that TBDMSb is a promising Sb precursor for low temperature OMVPE growth.

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

1992-06-01

156

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

157

Decomposition with Cheerios  

NSDL National Science Digital Library

The students will use Cheerios as manipulatives for decomposing numbers 5-10. Students will be encouraged to decompose numbers in as many different ways as possible. Students will also record their decompositions as addition problems.

Decloedt, Tracey

2012-07-06

158

New insights to the photometric structure of Blue Compact Dwarf galaxies from deep Near-Infrared studies. I. Observations, surface photometry and decomposition of surface brightness profiles  

NASA Astrophysics Data System (ADS)

We have analyzed deep Near Infrared (NIR) broad band images for a sample of Blue Compact Dwarf Galaxies (BCDs), observed with the ESO NTT and Calar Alto 3.6 m telescopes. The data presented here allows for the detection and quantitative study of the extended stellar low-surface brightness (LSB) host galaxy in all sample BCDs. NIR surface brightness profiles (SBPs) of the LSB host galaxies agree at large galactocentric radii with those from optical studies, showing also an exponential intensity decrease and compatible scale lengths. At small to intermediate radii (within 1-3 exponential scale lengths), however, the NIR data reveals for more than one half of our sample BCDs evidence for a significant flattening of the exponential profile of the LSB component. Such profiles (type V SBPs, Binggeli & Cameron \\cite{binggeli91}) have rarely been detected in the LSB component of BCDs at optical wavelengths, where the relative flux contribution of the starburst, being stronger than in the NIR, can readily hide a possible central intensity depression in the underlying LSB host. The structural properties, frequency and physical origin of type V LSB profiles in BCDs and dwarf galaxies in general have not yet been subject to systematic studies. Nevertheless, the occurrence of such profiles in an appreciable fraction of BCDs would impose important new observational constraints to the radial mass distribution of the stellar LSB component, as well as to the photometric fading of these systems after the termination of star-forming activities. We test the suitability of two empirical fitting functions, a modified exponential distribution (Papaderos et al. \\cite{papaderos96a}) and the Sérsic law, for the systematization of the structural properties of BCD host galaxies which show a type V intensity distribution. Either function has been found to satisfactorily fit a type V distribution. However, it is argued that the practical applicability of Sérsic fits to the LSB emission of BCDs is limited by the extreme sensitivity of the achieved solutions to, e.g., small uncertainties in the sky subtraction and SBP derivation. We find that most of the sample BCDs show in their stellar LSB host galaxy optical-NIR colors indicative of an evolved stellar population with subsolar metallicity. Unsharp-masked NIR maps reveal numerous morphological details and indicate in some cases, in combination with optical data, appreciable non-uniform dust absorption on a spatial scale as large as ~ 1 kpc. European Southern Observatory, program ID 65.N-0318(A). German-Spanish Astronomical Center, Calar Alto, operated by the Max-Planck-Institute for Astronomy, Heidelberg, jointly with the Spanish National Commission for Astronomy.

Noeske, K. G.; Papaderos, P.; Cairós, L. M.; Fricke, K. J.

2003-11-01

159

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

160

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. PMID:23785389

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

2013-01-01

161

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

NASA Technical Reports Server (NTRS)

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

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

2012-01-01

162

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

2011-05-26

163

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

ERIC Educational Resources Information Center

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

Bess, Cindy Rzasa

2009-01-01

164

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

165

Social?emotional well?being and resilience of children in early childhood settings – PERIK: an empirically based observation scale for practitioners  

Microsoft Academic Search

Compared with the traditional focus on developmental problems, research on positive development is relatively new. Empirical research in children's well?being has been scarce. The aim of this study was to develop a theoretically and empirically based instrument for practitioners to observe and assess preschool children's well?being in early childhood settings. The analysis of preschool teachers' ratings yields six dimensions of

Toni Mayr; Michaela Ulich

2009-01-01

166

Social-Emotional Well-Being and Resilience of Children in Early Childhood Settings--PERIK: An Empirically Based Observation Scale for Practitioners  

ERIC Educational Resources Information Center

Compared with the traditional focus on developmental problems, research on positive development is relatively new. Empirical research in children's well-being has been scarce. The aim of this study was to develop a theoretically and empirically based instrument for practitioners to observe and assess preschool children's well-being in early…

Mayr, Toni; Ulich, Michaela

2009-01-01

167

Observed Differences between Early Childhood Programs in the U.S. and Korea: Reflections of "Developmentally Appropriate Practices" in Two Cultural Contexts  

ERIC Educational Resources Information Center

Ninety children from South Korea and 119 children from the United States were observed in early childhood programs, and differences in classroom environments and teachers' and children's behavior in the two countries were identified. In both countries, there was evidence that preschool education is guided by ideas about "developmentally…

Clarke-Stewart, K. Alison; Lee, Young; Allhusen, Virginia D.; Kim, Myoung Soon; McDowell, David J.

2006-01-01

168

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

ERIC Educational Resources Information Center

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

Flensner, K. Kittelmann; Larsson, G.

2014-01-01

169

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

SciTech Connect

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

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

1994-01-01

170

Decomposition induced by mechanical milling  

Microsoft Academic Search

The decomposition behavior of FeSn, CoSn, CoIn2 and Al3Ni intermetallics under high-energy ball-milling has been investigated using X-ray diffraction, calorimetric and magnetization measurements. Upon milling a large amount of the FeSn inter metallic decomposes into Fe5Sn3 and FeSn2, where the average grain size of the product phases stays nearly constant with milling-time. Similar observations are made for the CoSn intermetallic,

Y. S. Kwon; P. P. Choi; J. S. Kim; K. B. Gerasimov

2005-01-01

171

Moment tensor decompositions revisited  

NASA Astrophysics Data System (ADS)

The decomposition of moment tensors into isotropic (ISO), double-couple (DC) and compensated linear vector dipole (CLVD) components is a tool for classifying and physically interpreting seismic sources. Since an increasing quantity and quality of seismic data allow inverting for accurate moment tensors and interpreting details of the source process, an efficient and physically reasonable decomposition of moment and source tensors is necessary. In this paper, the most common moment tensor decompositions are revisited, new equivalent formulas of the decompositions are derived, suitable norms of the moment tensors are discussed and the properties of commonly used source-type plots are analysed. The Hudson skewed diamond plot is introduced in a much simpler way than originally proposed. It is shown that not only the Hudson plot but also the diamond CLVD-ISO plot and the Riedesel-Jordan plot conserve the uniform distribution probability of moment eigenvalues if the appropriate norm of moment tensors is applied. When analysing moment tensor uncertainties, no source-type plot is clearly preferable. Since the errors in the eigenvectors and eigenvalues of the moment tensors cannot be easily separated, the moment tensor uncertainties project into the source-type plots in a complicated way. As a consequence, the moment tensors with the same uncertainties project into clusters of a different size. In case of an anisotropic focal area, the complexity of moment tensors of earthquakes prevents their direct interpretation, and the decomposition of moment tensors must be substituted by that of the source tensors.

Vavry?uk, Václav

2015-01-01

172

Normalized proper orthogonal decomposition (NPOD) for building pressure data compression  

Microsoft Academic Search

Proper orthogonal decomposition (POD) has been widely realized as a tool for compressing fluctuating building pressure data in wind-engineering area. Modes are determined by eigen decomposition of data covariance matrix, and then truncation is applied to retain only the modes with the highest energy. However, as observed by S. Kho, C. Baker, R. Hoxey [Pod\\/arma reconstruction of the surface pressure

Dan Ruan; Hua He; David A. Castañón; Kishor C. Mehta

2006-01-01

173

Characterization of microbial community in the leachate associated with the decomposition of entombed pigs.  

PubMed

Foot and mouth disease (FMD) is one of the acute infectious diseases in hoofed and even-toed mammals, including pigs, and it occurs via acute infection by Aphthovirus. When FMD is suspected, animals around the location of origin are typically slaughtered and buried. Other methods such as rendering, composting, and incineration have not been verified in practice in Korea. After the FMD incident, the regular monitoring of the microbial community is required, as microorganisms greatly modify the characteristics of the ecosystem in which they live. This is the result of their metabolic activities causing chemical changes to take place in the surrounding environment. In this study, we investigated changes in the microbial community during a 24 week period with DNA extracts from leachate, formed by the decomposition of buried pigs at a laboratory test site, using denaturing gradient gel electrophoresis (DGGE) with a genomic DNA. Our results revealed that Bacteroides coprosuis, which is common in pig excreta, and Sporanaerobacter acetigenes, which is a sulfur-reduced microbe, were continuously observed. During the early stages (0~2 weeks) of tissue decomposition, Clostridium cochlearium, Fusobacterium ulcerans, and Fusobacterium sp., which are involved in skin decomposition, were also observed. In addition, various microbes such as Turicibacter sanguinis, Clostridium haemolyticum, Bacteroides propionicifaciens, and Comamonas sp. were seen during the later stages (16~24 weeks). In particular, the number of existing microbial species gradually increased during the early stages, including the exponential phase, decreased during the middle stages, and then increased again during the later stages. Therefore, these results indicate that the decomposition of pigs continues for a long period of time and leachate is created continuously during this process. It is known that leachate can easily flow into the neighboring environment, so a long-term management plan is needed in burial locations for FMD-infected animals. PMID:23075782

Yang, Seung-Hak; Hong, Sun Hwa; Cho, Sung Back; Lim, Joung Soo; Bae, Sung Eun; Ahn, Heekwon; Lee, Eun Young

2012-10-01

174

Optimal domain decomposition strategies  

NASA Technical Reports Server (NTRS)

The primary interest of the authors is in the area of grid generation, in particular, optimal domain decomposition about realistic configurations. A grid generation procedure with optimal blocking strategies has been developed to generate multi-block grids for a circular-to-rectangular transition duct. The focus of this study is the domain decomposition which optimizes solution algorithm/block compatibility based on geometrical complexities as well as the physical characteristics of flow field. The progress realized in this study is summarized in this paper.

Yoon, Yonghyun; Soni, Bharat K.

1995-01-01

175

Mueller matrix differential decomposition.  

PubMed

We present a Mueller matrix decomposition based on the differential formulation of the Mueller calculus. The differential Mueller matrix is obtained from the macroscopic matrix through an eigenanalysis. It is subsequently resolved into the complete set of 16 differential matrices that correspond to the basic types of optical behavior for depolarizing anisotropic media. The method is successfully applied to the polarimetric analysis of several samples. The differential parameters enable one to perform an exhaustive characterization of anisotropy and depolarization. This decomposition is particularly appropriate for studying media in which several polarization effects take place simultaneously. PMID:21593943

Ortega-Quijano, Noé; Arce-Diego, José Luis

2011-05-15

176

Observation of Early Cleavage in Animal Development: A Simple Technique for Obtaining the Eggs of Rhabditis (Nematoda)  

ERIC Educational Resources Information Center

Outlines the advantages of using the readily available eggs of the nematode Rhabditis in studying the early cleavage stages of animal development. Discusses the identification and life history of Rhabditis, how to culture and examine the organism, the cleavage stages and cell lineage, and sources of visual aids. (JR)

Hinchliffe, J. R.

1973-01-01

177

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

ERIC Educational Resources Information Center

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

Clifford, Sally M; Dissanayake, Cheryl

2008-01-01

178

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

ERIC Educational Resources Information Center

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…

McCarthy, Kathrin W.; Duke, Thomas Scott

2007-01-01

179

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

180

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

Microsoft Academic Search

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

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

1997-01-01

181

Estimating the Effectiveness of Early Control Measures through School Absenteeism Surveillance in Observed Outbreaks at Rural Schools in Hubei, China  

PubMed Central

Background School absenteeism is a common data source in syndromic surveillance, which allows for the detection of outbreaks at an early stage. Previous studies focused on its correlation with other data sources. In this study, we evaluated the effectiveness of control measures based on early warning signals from school absenteeism surveillance in rural Chinese schools. Methods A school absenteeism surveillance system was established in all 17 primary schools in 3 adjacent towns in the Chinese region of Hubei. Three outbreaks (varicella, mumps, and influenza-like illness) were detected and controlled successfully from April 1, 2012, to January 15, 2014. An impulse susceptible-exposed-infectious-recovered model was used to fit the epidemics of these three outbreaks. Moreover, it simulated the potential epidemics under interventions resulting from traditional surveillance signals. The effectiveness of the absenteeism-based control measures was evaluated by comparing the simulated datasets. Results The school absenteeism system generated 52 signals. Three outbreaks were verified through epidemiological investigation. Compared to traditional surveillance, the school absenteeism system generated simultaneous signals for the varicella outbreak, but 3 days in advance for the mumps outbreak and 2–4 days in advance for the influenza-like illness outbreak. The estimated excess protection rates of control measures based on early signals were 0.0%, 19.0–44.1%, and 29.0–37.0% for the three outbreaks, respectively. Conclusions Although not all outbreak control measures can benefit from early signals through school absenteeism surveillance, the effectiveness of early signal-based interventions is obvious. School absenteeism surveillance plays an important role in reducing outbreak spread. PMID:25250786

Fan, Yunzhou; Yang, Mei; Jiang, Hongbo; Wang, Ying; Yang, Wenwen; Zhang, Zhixia; Yan, Weirong; Diwan, Vinod K.; Xu, Biao; Dong, Hengjin; Palm, Lars; Liu, Li; Nie, Shaofa

2014-01-01

182

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

183

Hydrazine decomposition and other reactions  

NASA Technical Reports Server (NTRS)

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

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

1978-01-01

184

Singular Value Decomposition  

E-print Network

. Exercise 6.1. Show that this is a valid inner product. Exercise 6.2. The trace of a matrix is the sum/4/9 page 86 i i i i 86 Chapter 6. Singular Value Decomposition the maximum amount of stretch possible matrix. Show the following additional facts, in light of the new norm definitions above. Exercise 6

Kilmer, Misha Elena

185

Decomposition of Mueller matrices  

Microsoft Academic Search

We present an algorithm which decomposes a Mueller matrix into a sequence of three matrix factors: a diattenuator, followed by a retarder, then followed by a depolarizer. Those factors are unique except for singular Mueller matrices. Based upon this decomposition, the diattenuation and retardance of a Mueller matrix can be defined and computed. Thus, this algorithm is useful for performing

Russell A. Chipman; Shih-Yau Lu

1997-01-01

186

Problem Decomposition for Reuse  

Microsoft Academic Search

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

Daniel Jackson; Michael Jackson

1995-01-01

187

Rainbow decompositions Raphael Yuster  

E-print Network

Rainbow decompositions Raphael Yuster Department of Mathematics University of Haifa Haifa 31905, Israel Abstract A rainbow coloring of a graph is a coloring of the edges with distinct colors. We prove-disjoint rainbow copies of Kk. Our proof uses, as a main ingredient, a double application of the probabilistic

Yuster, Raphael

188

Decomposition of dilute trichloroethylene by nonthermal plasma processing-gas flow rate, catalyst, and ozone effect  

Microsoft Academic Search

Decomposition performance of dilute (100-1000 ppm) trichloroethylene (TCE) contaminated in air by using nonthermal plasma processing was studied to improve the decomposition efficiency. Three kinds of experiments were performed. One is the observation of the decomposition efficiency related to the processing gas flow rate. There exists an optimal gas flow rate for our reactor. The second experiment is the plasma

Tetsuji Oda; Kei Yamaji; Tadashi Takahashi

2004-01-01

189

Episodic Accretion at Early Stages of Evolution of Low-Mass Stars and Brown Dwarfs: A Solution for the Observed Luminosity Spread in HR Diagrams?  

Microsoft Academic Search

We present evolutionary models for young low-mass stars and brown dwarfs taking into account episodic phases of accretion at early stages of the evolution, a scenario supported by recent large surveys of embedded protostars. An evolution including short episodes of vigorous accretion (\\\\dot{M}>= 10^{-4} M_&sun; yr^{-1}) followed by longer quiescent phases (\\\\dot{M}< 10^{-6} M_&sun; yr^{-1}) can explain the observed luminosity

I. Baraffe; G. Chabrier; J. Gallardo

2009-01-01

190

Low-Mass X-Ray Binaries and Globular Clusters in Early-Type Galaxies. I. Chandra Observations  

Microsoft Academic Search

We present a Chandra survey of LMXBs in 24 early-type galaxies. Correcting for detection incompleteness, the X-ray luminosity function (XLF) of each galaxy is consistent with a power law with negative logarithmic differential slope, beta~2.0. However, beta strongly correlates with incompleteness, indicating the XLF flattens at low-LX. The composite XLF is well fitted by a power law with a break

Philip J. Humphrey; David A. Buote

2008-01-01

191

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

192

The early stage of formation of self-organized nanocolumns in thin films: Monte Carlo simulations versus atomic-scale observations in Ge-Mn  

SciTech Connect

Formation kinetics of self-organized nanocolumns during epitaxial growth of a thin film composed of immiscible elements (A,B) has been investigated using Kinetic Monte Carlo simulations. Simulated nanostructures show a good agreement with those observed in Ge-Mn using Atom Probe Tomography and Transmission Electron Microscopy. Self organisation is observed although the rigid lattice simulations used do not account for misfit elastic strain. Simulations reveal that the final nanostructure, in term of number density and diameter of nanocolumns, is controlled by the early stages of growth of the film. The influence of both growth temperature and solute concentration on the nanostructure features is discussed in details.

Mouton, I.; Talbot, E., E-mail: etienne.talbot@univ-rouen.fr; Pareige, C.; Lardé, R.; Blavette, D. [Groupe de Physique des Matériaux (GPM) UMR 6634, Normandie Université, Université et INSA de Rouen - CNRS, Av. de l'Université, BP 12, 76801 Saint Etienne du Rouvray (France)

2014-02-07

193

Low-Mass X-ray Binaries and Globular Clusters in Early-Type Galaxies. I. Chandra Observations  

Microsoft Academic Search

We present a Chandra survey of LMXBs in 24 early-type galaxies. Correcting\\u000afor detection incompleteness, the X-ray luminosity function (XLF) of each\\u000agalaxy is consistent with a powerlaw with negative logarithmic differential\\u000aslope, beta~2.0. However, beta strongly correlates with incompleteness,\\u000aindicating the XLF flattens at low-Lx. The composite XLF is well-fitted by a\\u000apowerlaw with a break at 2.21(+0.65,-0.56)E38 erg\\/s

Philip J. Humphrey; David A. Buote

2006-01-01

194

Wood decomposition as influenced by invertebrates.  

PubMed

The diversity and habitat requirements of invertebrates associated with dead wood have been the subjects of hundreds of studies in recent years but we still know very little about the ecological or economic importance of these organisms. The purpose of this review is to examine whether, how and to what extent invertebrates affect wood decomposition in terrestrial ecosystems. Three broad conclusions can be reached from the available literature. First, wood decomposition is largely driven by microbial activity but invertebrates also play a significant role in both temperate and tropical environments. Primary mechanisms include enzymatic digestion (involving both endogenous enzymes and those produced by endo- and ectosymbionts), substrate alteration (tunnelling and fragmentation), biotic interactions and nitrogen fertilization (i.e. promoting nitrogen fixation by endosymbiotic and free-living bacteria). Second, the effects of individual invertebrate taxa or functional groups can be accelerative or inhibitory but the cumulative effect of the entire community is generally to accelerate wood decomposition, at least during the early stages of the process (most studies are limited to the first 2-3?years). Although methodological differences and design limitations preclude meta-analysis, studies aimed at quantifying the contributions of invertebrates to wood decomposition commonly attribute 10-20% of wood loss to these organisms. Finally, some taxa appear to be particularly influential with respect to promoting wood decomposition. These include large wood-boring beetles (Coleoptera) and termites (Termitoidae), especially fungus-farming macrotermitines. The presence or absence of these species may be more consequential than species richness and the influence of invertebrates is likely to vary biogeographically. PMID:25424353

Ulyshen, Michael D

2014-11-25

195

SoilLitter Mixing Accelerates Decomposition in a Chihuahuan  

E-print Network

Soil­Litter Mixing Accelerates Decomposition in a Chihuahuan Desert Grassland Daniel B. Hewins,1 to observed rates in dry- lands. This discrepancy indicates a significant gap in our mechanistic understanding

196

Combining field observations and modeling approaches to examine Greenland halibut (Reinhardtius hippoglossoides) early life ecology in the southeastern Bering Sea  

NASA Astrophysics Data System (ADS)

Spawning in Greenland halibut (Reinhardtius hippoglossoides) occurs along the continental slope and in submarine canyons in the eastern Bering Sea. It is assumed that these bathymetric features and their associated circulation patterns deliver eggs and larvae to suitable nursery habitats over the continental shelf. However, there have been no directed field studies examining spawning areas or transport of Greenland halibut early life stages in the Bering Sea, nor is it known how large-scale oceanographic forcing modulates specific physical mechanisms of delivery. The present study was undertaken to: better define spawning areas of Greenland halibut, examine development and distribution of larvae, and understand the influence of climate variations on interannual patterns of transport, distribution and abundance. Eggs were found in Bering and Pribilof Canyons and over the adjacent slope in February and early March, confirming that spawning occurs in these regions. Larvae were present over the slope, outer shelf and middle shelf in winter and spring, and settled juveniles were collected over the shelf in September. Oceanographic modeling approaches that simulate larval advection from spawning to nursery habitats indicate that depth-discrete variations in transport pathways from submarine canyons to the adjacent shelf contribute to interannual variability in transport trajectories. Overall, our results highlight specific physical mechanisms of delivery that are modulated by large-scale atmospheric and oceanographic forcing, potentially varying the degree of slope-shelf connectivity for Greenland halibut and other slope-spawning species.

Duffy-Anderson, J. T.; Blood, D. M.; Cheng, W.; Ciannelli, L.; Matarese, A. C.; Sohn, D.; Vance, T. C.; Vestfals, C.

2013-01-01

197

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

198

Decomposition mechanisms of dinitrotoluene  

NASA Astrophysics Data System (ADS)

To develop a viable detection system for 2,4-dinitrotoluene (DNT), its unimolecular decomposition mechanisms were studied by using the density functional theory. Three decomposition mechanisms were investigated: (1) homolytic cleavage; (2) migration of one of the O atoms in the NO2 groups to its neighboring C atoms; (3) migration of one of the H atoms in the methyl group to a neighboring O atom in the NO2 group. Only homolytic cleavage of the C bond N bond yields NO2 radicals with a total energy of 61 kcal/mol or more. Initial migration of the O atom to its second-nearest-neighbor C atom requires about 56 kcal/mol, but subsequent homolysis produces NO fragments with less energy sim15 kcal/mol. NO formation from both NO2 groups in 2,4-DNT is possible with a total energy of sim63 kcal/mol. The H-migration has the lowest energy barrier of 39 kcal/mol among the three initial decomposition mechanisms. Removing O directly from 2,4-DNT requires sim90 kcal/mol, while NO2 radical decomposes to NO and O with sim73 kcal/mol.

Tanaka, Genzo; Weatherford, Charles

199

Early Structural Anomalies Observed by High-Resolution Imaging in Two Related Cases of Autosomal-Dominant Retinitis Pigmentosa.  

PubMed

The authors report the use of adaptive-optics scanning laser ophthalmoscopy (AO-SLO) to investigate RHO, D190N autosomal-dominant retinitis pigmentosa in two siblings (11 and 16 years old, respectively). Each patient exhibited distinct hyperautofluorescence patterns in which the outer borders corresponded to inner segment ellipsoid band disruption. Areas within the hyperautofluorescence patterns exhibited normal photoreceptor outer segments and retinal pigment epithelium. However, AO-SLO imaging revealed noticeable spacing irregularities in the cone mosaic. AO-SLO allows researchers to characterize retinal structural abnormalities with precision so that early structural changes in retinitis pigmentosa can be identified and reconciled with genetic findings. [Ophthalmic Surg Lasers Imaging Retina. 2014;45:xxx-xxx.]. PMID:25215869

Park, Sung Pyo; Lee, Winston; Bae, Eun Jin; Greenstein, Vivianne; Sin, Bum Ho; Chang, Stanley; Tsang, Stephen H

2014-09-18

200

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

ERIC Educational Resources Information Center

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

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

2009-01-01

201

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

ERIC Educational Resources Information Center

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

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

2008-01-01

202

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

203

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

204

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

205

VLT and NTT Observations of Two EIS Cluster Candidates. Detection of the Early-Type Galaxies Sequence at z~1  

E-print Network

Optical data from the ESO VLT-UT1 Science Verification observations are combined with near-infrared data from SOFI at the NTT to obtain optical-infrared color-magnitude diagrams for the objects in the fields of two EIS cluster candidates. In both cases, evidence is found for a well-defined sequence of red galaxies that appear to be significantly more clustered than the background population. These results suggest that the two systems are real physical associations. The (R-Ks), (I-Ks) and (J-Ks) colors of the red sequences are used, in conjunction with similar data for spectroscopically confirmed clusters, to obtain redshift estimates of z ~ 0.9 and z ~ 1.0 for these two systems. These results make these EIS cluster candidates prime targets for follow-up spectroscopic observations to confirm their reality and to measure more accurately their redshift.

L. da Costa; M. Scodeggio; L. F. Olsen; M. Nonino; R. Rengelink; R. Bender; M. Franx; H. E. Jorgensen; A. Renzini; P. Rosati

1999-01-19

206

Hydraulic redistribution may stimulate decomposition  

Microsoft Academic Search

Roots influence root litter decomposition through multiple belowground processes. Hydraulic lift or redistribution (HR) by\\u000a plants is one such process that creates diel drying–rewetting cycles in soil. However, it is unclear if this phenomenon influences\\u000a decomposition. Since decomposition in deserts is constrained by low soil moisture and is stimulated when dry soils are rewetted,\\u000a we hypothesized that diel drying–rewetting, via

Zachary T. Aanderud; James H. Richards

2009-01-01

207

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

Microsoft Academic Search

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

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

2010-01-01

208

Observations of cosmic ray electrons and positrons during the early stages of the A- magnetic polarity epoch  

Microsoft Academic Search

As part of our ongoing investigation of the charge sign dependence in solar modulation, we measured the cosmic ray positron abundance (0.8 GeV to 4.5 GeV) and electron flux (20 MeV to 4.5 GeV) on balloon flights from Lynn Lake, Manitoba during August 2002. We find that the decrease in the positron abundance observed in 2000 persists in 2002. The

John Clem; Paul Evenson

2004-01-01

209

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

210

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

NASA Technical Reports Server (NTRS)

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

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

2012-01-01

211

The Size Evolution of Passive Galaxies: Observations From the Wide-Field Camera 3 Early Release Science Program  

NASA Technical Reports Server (NTRS)

We present the size evolution of passively evolving galaxies at z approximately 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 greater than approximately 1.5. We identify 30 galaxies in approximately 40 arcmin(sup 2) to H less than 25 mag. By fitting the 10-band Hubble Space Telescope photometry from 0.22 micrometers less than approximately lambda (sub obs) 1.6 micrometers 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 approximately 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 *) approximately 10(sup 11) solar mass) undergo the strongest evolution from z approximately 2 to the present. Parameterizing the size evolution as (1 + z)(sup - alpha), we find a tentative scaling of alpha approximately equals (-0.6 plus or minus 0.7) + (0.9 plus or minus 0.4) log(M(sub *)/10(sup 9 solar mass), where the relatively large uncertainties reflect the poor sampling in stellar mass due to the low numbers of highredshift 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.; Mccarthy, P.J.; Cohen, S. H.; Yan, H.; Hathi, N. P.; Koekemoer, A. M.; Rutkowski, M. J.; Mechtley, M. R.; Windhorst, R. A.; O’Connell, R. W.; Balick, B.; Bond, H. E.; Bushouse, H.; Calzetti, D.; Crockett, R. M.; Disney, M.; Dopita, M. A.; Frogel, J. A.; Hall, D., N., B.; Holtzman, J. A.; Kaviraj, S.; Kimble, R. A.; MacKenty, J.; Trauger, J.; Young, E.

2012-01-01

212

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

NASA Astrophysics Data System (ADS)

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.

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

2007-11-01

213

Hydrogen peroxide catalytic decomposition  

NASA Technical Reports Server (NTRS)

Nitric oxide in a gaseous stream is converted to nitrogen dioxide using oxidizing species generated through the use of concentrated hydrogen peroxide fed as a monopropellant into a catalyzed thruster assembly. The hydrogen peroxide is preferably stored at stable concentration levels, i.e., approximately 50%-70% by volume, and may be increased in concentration in a continuous process preceding decomposition in the thruster assembly. The exhaust of the thruster assembly, rich in hydroxyl and/or hydroperoxy radicals, may be fed into a stream containing oxidizable components, such as nitric oxide, to facilitate their oxidation.

Parrish, Clyde F. (Inventor)

2010-01-01

214

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

215

Mode decomposition evolution equations  

PubMed Central

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

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

2011-01-01

216

Decomposition Products of Rdx and TNT after Resonant Laser Excitation  

NASA Astrophysics Data System (ADS)

This paper describes research on the gas-phase decomposition products of explosives after resonant laser exposure. We studied RDX and TNT exposed to lasers in the infrared (10.6 ?m continuous-wave [cw]) and ultraviolet (266 nm cw and pulsed [˜8 ns pulsewidth]). The decomposition products in air were identified by infrared spectroscopy and mass spectrometry; NO2 was observed from both RDX and TNT. For RDX, the N2O:NO2 vapor product ratio was lower for the 266 nm pulsed case (0.2) than the cw cases (0.9), suggesting a faster timescale of energy deposition favors one decomposition pathway over another.

Monat, J. E.; Gump, J. C.

2009-12-01

217

Shock Wave-Induced Chemical Decomposition of RDX Crystals  

NASA Astrophysics Data System (ADS)

Time-resolved optical spectroscopy and quantum chemistry calculations were combined to gain insight into molecular processes in shock-induced decomposition of RDX. Crystals of [111] orientation were shocked to peak stresses between 7.0 and 20.0 GPa. Broadband light emission was observed over the range of 350 - 850 nm with a threshold in spectral behavior at about 10 GPa. Below this threshold, the spectral profile remained unchanged during the experiment. Above 10 GPa, the emission spectrum changed with time and shifted to longer wavelengths. Based on these observations and quantum calculations, the emission spectrum was assigned to NO2 radicals and HONO intermediates. Unimolecular decomposition of RDX leads to the production of these species through multiple decomposition steps. The observed threshold behavior is proposed to be due to the onset of bimolecular reactions between radical decomposition products and unreacted RDX molecules. We put forward a full decomposition scheme consistent with the main observations from our spectroscopy experiments. This work demonstrates the value of combining spectroscopy experiments with first principles calculations to understand decomposition of HE crystals.

Dreger, Zbigniew; Patterson, James; Miao, Maosheng; Gupta, Yogendra

2009-06-01

218

The Study of Dusty Star-Forming Galaxies in the Early Universe Through Far-Infrared Observations  

NASA Astrophysics Data System (ADS)

In this thesis I use far-infrared (far-IR) observations performed by the Herschel Space Observatory to study dusty star-forming galaxies, which are believed to be the likely progenitors of massive elliptical galaxies. More specifically, I investigate the far-IR emission of dust-obscured galaxies (DOGs), analyze the near-IR imaging of Herschel-selected lensed galaxies, and investigate the rest-frame UV emission of HFLS3, a z = 6.34 Herschel-selected starburst.

Calanog, Jae Alyson

219

Chain decomposition of aqueous triethanolamine. [Gamma Radiation  

Microsoft Academic Search

A radiation-induced chain decomposition of aqueous triethanolamine into acetaldehyde and diethanolamine is reported. Chain lengths over 1000 have been observed, depending on pH, concentration, and radiation intensity. The chain propagation steps include OH group migration in the 2-hydroxy-1-(diethanolamino)ethyl radical and NRâ migration in 1-hydroxy-2(diethanolamine)ethyl radical, each producing a 2-hydroxy-2-(diethanolamine)ethyl radical. Free-radical spectra and rate constants are given. Studies of diethanolamine

1982-01-01

220

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

221

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

NASA Technical Reports Server (NTRS)

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

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

2007-01-01

222

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

E-print Network

We present four spectra of the Type Ia supernova (SN Ia) 2006D extending from -7 to +13 days with respect to B-band maximum. The spectra include the strongest signature of unburned material at photospheric velocities observed in a SN Ia to date. The earliest spectrum exhibits C II absorption features below 14,000 km/s, including a distinctive C II \\lambda 6580 absorption feature. The carbon signatures dissipate as the SN approaches peak brightness. In addition to discussing implications of photospheric-velocity carbon for white dwarf explosion models, we outline some factors that may influence the frequency of its detection before and around peak brightness. Two effects are explored in this regard, including depopulation of the C II optical levels by non-LTE effects, and line-of-sight effects resulting from a clumpy distribution of unburned material with low volume-filling factor.

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

2006-11-10

223

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

224

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

225

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

226

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

NASA Technical Reports Server (NTRS)

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

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

2004-01-01

227

One Dose versus Three Weekly Doses of Benzathine Penicillin G for Patients Co-Infected with HIV and Early Syphilis: A Multicenter, Prospective Observational Study  

PubMed Central

Background One dose of benzathine penicillin G (BPG) has been recommended for HIV-infected patients with early syphilis (primary, secondary, and early latent syphilis) in the sexually transmitted diseases treatment guidelines, but clinical data to support such a recommendation are limited. Methods We prospectively observed the serological response to 1 or 3 weekly doses of BPG in HIV-infected adults who sought treatment of early syphilis at 8 hospitals around Taiwan. Rapid plasma reagin (RPR) titers were followed every 3–6 months after treatment. The serological response was defined as a 4-fold or greater decline in RPR titers at 12 months of treatment. The missing values were treated by following the last-observed-carried-forward principle. We hypothesized that 1 dose was non-inferior to 3 weekly doses of BPG with the non-inferiority margin for the difference of serological response set to 10%. Results Between 2007 and 2012, 573 patients completed at least 12 months of follow-up: 295 (51.5%) receiving 1 dose of BPG (1-dose group) and 278 (48.5%) 3 doses (3-dose group). Overall, 198 patients (67.1%; 95% confidence interval [CI], 61.4–72.5%) in the 1-dose group achieved serological response at 12 months, as did 208 patients (74.8%; 95% CI, 69.3–79.8%) in the 3-dose group (one-sided 95% CI of the difference, 15.1%). In the multivariate analysis, secondary syphilis (adjusted odds ratio [AOR], 1.90; 95% CI 1.17–3.09), RPR titer ?32 (AOR, 1.93; 95% CI, 1.38–2.69), and 3 doses of BPG (AOR, 1.68; 95% CI, 1.20–2.36) were independently associated with a serological response. The time to the first episode of treatment failure was 1184 (standard deviation [SD], 70.5) and 1436 (SD, 80.0) days for 1- and 3-dose group, respectively. Conclusions Single-dose BPG resulted in a higher serological failure rate and shorter time to treatment failure than 3 weekly doses of BPG in the treatment of early syphilis in HIV-infected patients. PMID:25286091

Yang, Chia-Jui; Lee, Nan-Yao; Chen, Tun-Chieh; Lin, Yu-Hui; Liang, Shiou-Haur; Lu, Po-Liang; Huang, Wen-Chi; Tang, Hung-Jen; Lee, Chen-Hsiang; Lin, Hsi-Hsun; Chen, Yen-Hsu; Ko, Wen-Chien; Hung, Chien-Ching

2014-01-01

228

Outline of the 2011 off the Pacific coast of Tohoku Earthquake (Mw 9.0) - Earthquake Early Warning and observed seismic intensity  

NASA Astrophysics Data System (ADS)

The 2011 off the Pacific coast of Tohoku Earthquake (Mw 9.0) that occurred on March 11, 2011, caused strong ground motion around northeastern Japan. Before the strong ground motion hit cities, the Japan Meteorological Agency (JMA) issued Earthquake Early Warning (EEW) announcements to the general public of the Tohoku district and then the warning was automatically broadcast through TV, radios and cellular phone mails. The EEW was earlier than the S wave arrival and more than 15 s earlier than the strong ground motion (intensity 5-lower or greater on the JMA scale) everywhere in the district. Seismic intensity 7 was observed for only the second time since JMA introduced instrument-based observation for intensity measurements in 1996. Intensities of 6-upper and 6-lower were widely observed at many stations in the Tohoku and Kanto districts, over an area of approximately 400 km × 100 km. The duration of strong ground motions was quite long. For the Tokyo region, JMA EEW expected intensities of 4, which was an underestimation of the observed intensity (5-upper). This underestimation can probably be attributed to the large extent of the fault rupture.

Hoshiba, M.; Iwakiri, K.; Hayashimoto, N.; Shimoyama, T.; Hirano, K.; Yamada, Y.; Ishigaki, Y.; Kikuta, H.

2011-07-01

229

Evidence of Multiple r-Process Sites in the Early Galaxy: New Observations of CS 22892-052  

E-print Network

First results are reported of a new abundance study of neutron-capture elements in the ultra-metal-poor (UMP; [Fe/H] = -3.1) halo field giant star CS 22892-052. Using new high resolution, high signal-to-noise spectra, abundances of more than 30 neutron-capture elements (Z>30) have been determined. Six elements in the 40=56) stable neutron-capture elements in CS 22892-052 match well the scaled solar system r-process abundance distribution. From the observed Th abundance, an average age of ~= 16 +/- 4 Gyr is derived for cs22892-052, consistent with the lower age limit of ~= 11 Gyr derived from the upper limit on the U abundance. The concordance of scaled solar r-process and CS 22892-052 abundances breaks down for the lighter neutron-capture elements, supporting previous suggestions that different r-process production sites are responsible for lighter and heavier neutron-capture elements.

Christopher Sneden; John J. Cowan; Inese I. Ivans; George M. Fuller; Scott Burles; Timothy C. Beers; James E. Lawler

2000-03-07

230

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 direct…

Thaheem, A. B.

2005-01-01

231

Modular decomposition and transitive orientation  

Microsoft Academic Search

Abstract A module of an undirected graph is a set X of nodes such for each node x not in X, either every member of X is adjacent to x, or no member of X is adjacent to x. There is a canonical linear-space representation for the modules of a graph, called the modular decomposition. Closely related to modular decomposition

Ross M. Mcconnell; Jeremy P. Spinrad

1999-01-01

232

Sonochemical acceleration of persulfate decomposition  

Microsoft Academic Search

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

Gareth J. Price; Andrew A. Clifton

1996-01-01

233

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

234

The Resolved Stellar Population in 50 Regions of M83 from HST/WFC3 Early Release Science Observations  

NASA Astrophysics Data System (ADS)

We present a multi-wavelength photometric study of ~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; Whitmore, Bradley C.; Chandar, Rupali; Saha, Abhijit; Kaleida, Catherine C.; Mutchler, Max; Cohen, Seth H.; Calzetti, Daniela; O'Connell, Robert W.; Windhorst, Rogier A.; Balick, Bruce; Bond, Howard E.; Carollo, Marcella; Disney, Michael J.; Dopita, Michael A.; Frogel, Jay A.; Hall, Donald N. B.; Holtzman, Jon A.; Kimble, Randy A.; McCarthy, Patrick J.; Paresce, Francesco; Silk, Joe I.; Trauger, John T.; Walker, Alistair R.; Young, Erick T.

2012-07-01

235

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. PMID:16476673

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

2006-01-01

236

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

PubMed Central

Introduction Inflammation and coagulation are closely linked, and both can be triggered by endotoxin. Thrombelastometry and impedance aggregometry are of diagnostic and predictive value in critically ill patients. In this observational study we investigated the correlation of endotoxin activity with thrombelasometric and aggregometric variables in patients with systemic inflammation. Methods Based on a daily screening on a tertiary academic surgical ICU, patients, as soon as they fulfilled two or more criteria for systemic inflammatory response syndrome (SIRS), were included. In whole blood we performed endotoxin activity (EA) assay, thrombelastometry (ROTEM®) and impendance aggregometry (Multiplate®). Results In total, 49 patients were included with a broad spread of EA levels of (median (minimum to maximum)) 0.27 (0.01 to 0.72), allowing expedient correlative analysis. Clot formation time (CFT) (263 s (60 to 1,438 s)) and clotting time (CT) (1,008 s (53 to 1,481 s)) showed a significant negative correlation with EA level (r = -0.38 (P < 0.005) and r = -0.29 (P < 0.05)). Positive correlations were found for alpha-angle (50° (17 to 78°), r = 0.40 (P < 0.005)) and maximum clot firmness (MCF) (55 mm (5/76), r = 0.27 (P < 0.05)). No significant correlations were found between Lysis Index at 60 minutes (LI60) and EA levels. There was no correlation between EA level and aggregometric values, or classical coagulation parameters. Conclusions In patients with systemic inflammation, increasing endotoxin concentrations correlate with increased clot formation. PMID:24025340

2013-01-01

237

The Resolved Stellar Population in 50 Regions of M83 from HST/WFC3 Early Release Science Observations  

NASA Technical Reports Server (NTRS)

We present a multi-wavelength photometric study of approximately 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 ofWolf-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; Whitmore, Bradley C.; Chandar, Rupali; Saha, Abhijit; Kaleida, Catherine C.; Mutchler, Max; Cohen, Seth H.; Calzetti, Daniela; O’Connell, Robert W.; Windhorst, Rogier A.; Balick, Bruce; Bond, Howard E.; Carollo, Marcella; Disney, Michael J.; Dopita, Michael A.; Frogel, Jay A.; Hall, Donald N. B.; Holtzman, Jon A.; Kimble, Randy A.; McCarthy, Patrick J.; Paresce, Francesco; Silk, Joe I; Trauger, John T.; Walker, Alistair R.; Young, Erick T.

2012-01-01

238

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

PubMed Central

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

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

2014-01-01

239

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

PubMed

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

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

2014-01-01

240

Art of spin decomposition  

E-print Network

We analyze the problem of spin decomposition for an interacting system from a natural perspective of constructing angular momentum eigenstates. We split, from the total angular momentum operator, a proper part which can be separately conserved for a stationary state. This part commutes with the total Hamiltonian and thus specifies the quantum angular momentum. We first show how this can be done in a gauge-dependent way, by seeking a specific gauge in which part of the total angular momentum operator vanishes identically. We then construct a gauge-invariant operator with the desired property. Our analysis clarifies what is the most pertinent choice among the various proposals for decomposing the nucleon spin. A similar analysis is performed for extracting a proper part from the total Hamiltonian to construct energy eigenstates.

Xiang-Song Chen; Wei-Min Sun; Fan Wang; T. Goldman

2011-05-31

241

Fast Approximate Convex Decomposition  

E-print Network

: D(M) = Mij[iMi = Mand 8i 6=jM i \\M j = ; (3.1) where M i is the open set of Mi, i.e.,Mi excluding its boundary. De nition .2 The cuts fCig in a decomposition D of a model M , are the maxi- mal boundaries of the components Mi... that are not boundaries of M . Note that the 8 f b c h x a ?2 d e y g ?0?1 ?3 Fig. 1.: Bridges 0, 1, 2, and 3, and their pocket minima. Bridges 0 and 1 are the kids of 2. application of fCig on M gives the components fMig. Although in 3D a cut is de...

Ghosh, Mukulika

2012-10-19

242

Evolutionary Speciation for Problem Decomposition Justinian Rosca  

E-print Network

Evolutionary Speciation for Problem Decomposition Justinian Rosca University of Rochester Dept, a decomposition architecture must be speci ed in advance. This paper presents the Evolutionary Speciation Genetic

Fernandez, Thomas

243

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

244

Early Stages of Sn-Doped In2O3 Film Growth on Amorphous SiO2 Surfaces Observed by Atomic Force Microscopy and Transmission Electron Microscopy  

NASA Astrophysics Data System (ADS)

The early stages of Sn-doped In2O3 (ITO) film growth on amorphous SiO2 (a-SiO2) surfaces were observed by atomic force microscopy (AFM) and transmission electron microscopy (TEM). AFM measurements clearly showed that the surface morphologies of the ITO films (3-6 nm in thickness) possessed an extended hill-and-valley structure. TEM analysis revealed that small ITO islands on the a-SiO2 surface could aggregate, resulting in the formation of larger ITO islands approximately 15-30 nm in diameter. The combined results indicate that the ITO film growth on a-SiO2 surfaces is similar to that on glass surfaces.

Sato, Yasushi; Oka, Nobuto; Nakamura, Shin-ichi; Shigesato, Yuzo

2013-12-01

245

Spinodal decomposition as a probe to measure the effects on molecular motion in poly(styrene-co-acrylonitrile) and poly(methyl methacrylate) blends after mixing with a low molar mass liquid crystal or commercial lubricant  

Microsoft Academic Search

The effects on molecular motion observed through early stage phase separation via spinodal decomposition, in melt mixed poly(styrene-co-acrylonitrile) (SAN) containing 25% by weight of acrylonitrile (AN) and poly(methyl methacrylate) (PMMA) (20\\/80wt%) blends after adding two low molar mass liquid crystals (CBC33 and CBC53) and two lubricants (GMS and zinc stearate) were investigated using light scattering techniques. The samples were assessed

S. Wacharawichanant; S. Thongyai; S. Tanodekaew; J. S. Higgins; N. Clarke

2004-01-01

246

Early Algebra, Early Arithmetic  

NSDL National Science Digital Library

This site offers a variety of early algebra resources for teachers in grades 1-6, parents, researchers, policy makers, administrators, and curriculum developers. Site includes early algebra activities, handouts and overheads in PDF format (requires Acrobat Reader), articles, short reviews of articles and books focusing on early math and early algebra, news and events, and more. A valuable source for pre algebra activities in the elementary classroom.

National Science Foundation (NSF)

2007-12-12

247

Shock wave induced decomposition of RDX: time-resolved spectroscopy.  

PubMed

Time-resolved optical spectroscopy was used to examine chemical decomposition of RDX crystals shocked along the [111] orientation to peak stresses between 7 and 20 GPa. Shock-induced emission, produced by decomposition intermediates, was observed over a broad spectral range from 350 to 850 nm. A threshold in the emission response of RDX was found at about 10 GPa peak stress. Below this threshold, the emission spectrum remained unchanged during shock compression. Above 10 GPa, the emission spectrum changed with a long wavelength component dominating the spectrum. The long wavelength emission is attributed to the formation of NO2 radicals. Above the 10 GPa threshold, the spectrally integrated intensity increased significantly, suggesting the acceleration of chemical decomposition. This acceleration is attributed to bimolecular reactions between unreacted RDX and free radicals. These results provide a significant experimental foundation for further development of a decomposition mechanism for shocked RDX (following paper in this issue). PMID:18642891

Patterson, James E; Dreger, Zbigniew A; Miao, Maosheng; Gupta, Yogendra M

2008-08-14

248

Nonequilibrium adiabatic molecular dynamics simulations of methane clathrate hydrate decomposition  

NASA Astrophysics Data System (ADS)

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.

Alavi, Saman; Ripmeester, J. A.

2010-04-01

249

[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

250

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

251

Perfluoropolyalkylether decomposition on catalytic aluminas  

NASA Technical Reports Server (NTRS)

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

Morales, Wilfredo

1994-01-01

252

Azimuthal decomposition with digital holograms.  

PubMed

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

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

2012-05-01

253

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

254

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

255

Actual-Waste Tests of Enhanced Chemical Cleaning for Retrieval of SRS HLW Sludge Tank Heels and Decomposition of Oxalic Acid - 12256  

SciTech Connect

Savannah River National Laboratory conducted a series of tests on the Enhanced Chemical Cleaning (ECC) process using actual Savannah River Site waste material from Tanks 5F and 12H. Testing involved sludge dissolution with 2 wt% oxalic acid, the decomposition of the oxalates by ozonolysis (with and without the aid of ultraviolet light), the evaporation of water from the product, and tracking the concentrations of key components throughout the process. During ECC actual waste testing, the process was successful in decomposing oxalate to below the target levels without causing substantial physical or chemical changes in the product sludge. During ECC actual waste testing, the introduction of ozone was successful in decomposing oxalate to below the target levels. This testing did not identify physical or chemical changes in the ECC product sludge that would impact downstream processing. The results from these tests confirm observations made by AREVA NP during larger scale testing with waste simulants. This testing, however, had a decreased utilization of ozone, requiring approximately 5 moles of ozone per mole of oxalate decomposed. Decomposition of oxalates in sludge dissolved in 2 wt% OA to levels near 100 ppm oxalate using ECC process conditions required 8 to 12.5 hours without the aid of UV light and 4.5 to 8 hours with the aid of UV light. The pH and ORP were tracked during decomposition testing. Sludge components were tracked during OA decomposition, showing that most components have the highest soluble levels in the initial dissolved sludge and early decomposition samples and exhibit lower soluble levels as OA decomposition progresses. The Deposition Tank storage conditions that included pH adjustment to approximately 1 M free hydroxide tended to bring the soluble concentrations in the ECC product to nearly the same level for each test regardless of storage time, storage temperature, and contact with other tank sludge material. (authors)

Martino, Christopher J.; King, William D. [Savannah River National Laboratory, Aiken, SC 29808 (United States); Ketusky, Edward T. [Savannah River Remediation, Aiken, SC 29808 (United States)

2012-07-01

256

Observation of wavelength-sensitive mass-independent sulfur isotope effects during SO2 photolysis: Implications for the early atmosphere  

NASA Astrophysics Data System (ADS)

Mass-independent isotopic signatures for ?33S, ?34S, and ?36S produced in the photolysis of sulfur dioxide exhibit a strong wavelength dependence. Photolysis experiments with three light sources (ArF excimer laser (193 nm), mercury resonance lamp (184.9 and 253.7 nm), and KrF excimer laser (248 nm) are presented. Products of sulfur dioxide photolysis undertaken with 193-nm radiation exhibit characteristics that are similar to sulfur multiple-isotope data for terrestrial sedimentary rock samples older than 2450 Ma (reported by Farquhar et al. [2000a]), while photolysis experiments undertaken with radiation at other wavelengths (longer than 220 nm and at 184.9 nm) exhibit different characteristics. The spectral window between 190 and 220 nm falls between the Schumann-Runge bands of oxygen and the Hartley bands of ozone, and its absorption is therefore more sensitive to changes in altitude and atmospheric oxygen content than neighboring wavelengths. These two observations are used to suggest a link between sulfur dioxide photolysis at 193 nm and sulfur isotope anomalies in Archean rocks. This hypothesis includes the suggestion that UV wavelengths shorter than 200 nm penetrated deep in the Earth's atmosphere during the Archean. Potential implications of this hypothesis for the chemistry, composition, and UV absorption of the atmosphere are explored. We also explore the implications of these observations for documentation of bacterial sulfur metabolisms early in Earth's history.

Farquhar, James; Savarino, Joel; Airieau, Sabine; Thiemens, Mark H.

2001-12-01

257

Catalyst for sodium chlorate decomposition  

NASA Technical Reports Server (NTRS)

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

Wydeven, T.

1972-01-01

258

The combinatorics of reduced decompositions  

E-print Network

This thesis examines several aspects of reduced decompositions in finite Coxeter groups. Effort is primarily concentrated on the symmetric group, although some discussions are subsequently expanded to finite Coxeter groups ...

Tenner, Bridget Eileen

2006-01-01

259

Thermal decomposition of ethylpentaborane in gas phase  

NASA Technical Reports Server (NTRS)

The thermal decomposition of ethylpentaborane at temperatures of 185 degrees to 244 degrees C is approximately a 1.5-order reaction. The products of the decomposition were hydrogen, methane, a nonvolatile boron hydride, and traces of decaborane. Measurements of the rate of decomposition of pentaborane showed that ethylpentaborane has a greater rate of decomposition than pentaborane.

Mcdonald, Glen E

1956-01-01

260

Optimization by nonhierarchical asynchronous decomposition  

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

261

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

262

Sector decomposition via computational geometry  

E-print Network

A non-iterative method is presented for the factorization step of sector decomposition method, which separates infrared divergent part from loop integration. This method is based on a classification of asymptotic behavior of polynomials. The problem is converted to ones for convex body in Euclidean space. They are solved with algorithms developed in computational geometry. A test implementation shows that this method produces less number of decomposed sectors than usual iterative sector decompositions.

Toshiaki Kaneko; Takahiro Ueda

2010-04-30

263

Nontraditional tensor decompositions and applications.  

SciTech Connect

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

Bader, Brett William

2010-07-01

264

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

NASA Astrophysics Data System (ADS)

As the use of microsystems has become more widespread, the need for reduced order models that accurately and efficiently predict their dynamic behavior has also grown. Proper orthogonal decomposition (POD) has proven to be a beneficial model-reduction tool in structural dynamics; however, its use in the development of reduced order models of microsystems from experimental data has not received much attention. In this paper, we combine a scanning laser vibrometer with a fully functional atomic force microscope (AFM) to measure the vibration field of AFM microcantilevers tapping on stiff and soft samples. Both stiff and soft AFM microcantilevers with internal resonance are studied. This represents a wide class of vibrating microsystems with spatially confined nonlinearity at the sharp probe tip arising from short and long range surface forces. We apply POD to the measured vibration field of AFM cantilevers and show that a small number of experimentally extracted proper orthogonal modes (POMs) can accurately represent the nonlinear microcantilever dynamics under a variety of conditions. Moreover only one or two sets of POMs are needed to represent the dynamics under a wide range of operating conditions including in the attractive and repulsive regimes of oscillation.

Spletzer, Matthew; Raman, Arvind; Reifenberger, Ron

2010-08-01

265

Chain decomposition of aqueous triethanolamine. [Gamma Radiation  

SciTech Connect

A radiation-induced chain decomposition of aqueous triethanolamine into acetaldehyde and diethanolamine is reported. Chain lengths over 1000 have been observed, depending on pH, concentration, and radiation intensity. The chain propagation steps include OH group migration in the 2-hydroxy-1-(diethanolamino)ethyl radical and NR/sub 2/ migration in 1-hydroxy-2(diethanolamine)ethyl radical, each producing a 2-hydroxy-2-(diethanolamine)ethyl radical. Free-radical spectra and rate constants are given. Studies of diethanolamine and diethylethanolamine solutions gave similar free-radical spectra but much shorter chains.

Schwarz, H.A.

1982-08-19

266

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

E-print Network

We analyze the spectral energy distributions (SEDs) of Lyman break galaxies (LBGs) at z=1-3 selected using the Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) UVIS channel filters. These HST/WFC3 observations cover about 50 sq. arcmin in the GOODS-South field as a part of the WFC3 Early Release Science program. These LBGs at z=1-3 are selected using dropout selection criteria similar to high redshift LBGs. The deep multi-band photometry in this field is used to identify best-fit SED models, from which we infer the following results: (1) the photometric redshift estimate of these dropout selected LBGs is accurate to within few percent; (2) the UV spectral slope {\\beta} is redder than at high redshift (z>3), where LBGs are less dusty; (3) on average, LBGs at z=1-3 are massive, dustier and more highly star-forming, compared to LBGs at higher redshifts with similar luminosities, though their median values are similar within 1{\\sigma} uncertainties. This could imply that identical dropout selection techniq...

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

2012-01-01

267

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

268

Formation of thermal decomposition cavities in physical vapor transport of silicon carbide  

Microsoft Academic Search

The relationship between seed mounting and the formation of thermal decomposition cavities in physical vapor transport grown silicon carbide was investigated. Scanning electron microscopy, energy dispersive x-ray spectroscopy, Auger electron spectroscopy, and optical microscopy were used to characterize thermal decomposition cavities at various stages of their development. The observations indicate that the attachment layer that holds the seed to the

Edward K. Sanchez; Thomas Kuhr; Volker D. Heydemann; David W. Snyder; Gregory S. Rohrer; Marek Skowronski

2000-01-01

269

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

270

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

271

Thermal decomposition and non-isothermal decomposition kinetics of carbamazepine  

NASA Astrophysics Data System (ADS)

The thermal stability and kinetics of isothermal decomposition of carbamazepine were studied under isothermal conditions by thermogravimetry (TGA) and differential scanning calorimetry (DSC) at three heating rates. Particularly, transformation of crystal forms occurs at 153.75°C. The activation energy of this thermal decomposition process was calculated from the analysis of TG curves by Flynn-Wall-Ozawa, Doyle, distributed activation energy model, Šatava-Šesták and Kissinger methods. There were two different stages of thermal decomposition process. For the first stage, E and log A [s-1] were determined to be 42.51 kJ mol-1 and 3.45, respectively. In the second stage, E and log A [s-1] were 47.75 kJ mol-1 and 3.80. The mechanism of thermal decomposition was Avrami-Erofeev (the reaction order, n = 1/3), with integral form G(?) = [-ln(1 - ?)]1/3 (? = ˜0.1-0.8) in the first stage and Avrami-Erofeev (the reaction order, n = 1) with integral form G(?) = -ln(1 - ?) (? = ˜0.9-0.99) in the second stage. Moreover, ? H ?, ? S ?, ? G ? values were 37.84 kJ mol-1, -192.41 J mol-1 K-1, 146.32 kJ mol-1 and 42.68 kJ mol-1, -186.41 J mol-1 K-1, 156.26 kJ mol-1 for the first and second stage, respectively.

Qi, Zhen-li; Zhang, Duan-feng; Chen, Fei-xiong; Miao, Jun-yan; Ren, Bao-zeng

2014-12-01

272

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

273

In Situ Infrared Study of Catalytic Decomposition of NO  

SciTech Connect

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

Cher-Dip Tan; Steven S.C. Chuang

1997-07-17

274

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

275

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

SciTech Connect

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

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

2013-06-10

276

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

NASA Astrophysics Data System (ADS)

We analyze the spectral energy distributions (SEDs) of Lyman break galaxies (LBGs) at z ~= 1-3 selected using the Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) UVIS channel filters. These HST/WFC3 observations cover about 50 arcmin2 in the GOODS-South field as a part of the WFC3 Early Release Science program. These LBGs at z ~= 1-3 are selected using dropout selection criteria similar to high-redshift LBGs. The deep multi-band photometry in this field is used to identify best-fit SED models, from which we infer the following results: (1) the photometric redshift estimate of these dropout-selected LBGs is accurate to within few percent; (2) the UV spectral slope ? is redder than at high redshift (z > 3), where LBGs are less dusty; (3) on average, LBGs at z ~= 1-3 are massive, dustier, and more highly star forming, compared to LBGs at higher redshifts with similar luminosities (0.1L* <~ L <~ 2.5L*), though their median values are similar within 1? uncertainties. This could imply that identical dropout selection technique, at all redshifts, finds physically similar galaxies; and (4) the stellar masses of these LBGs are directly proportional to their UV luminosities with a logarithmic slope of ~0.46, and star formation rates are proportional to their stellar masses with a logarithmic slope of ~0.90. These relations hold true—within luminosities probed in this study—for LBGs from z ~= 1.5 to 5. The star-forming galaxies selected using other color-based techniques show similar correlations at z ~= 2, but to avoid any selection biases, and for direct comparison with LBGs at z > 3, a true Lyman break selection at z ~= 2 is essential. The future HST UV surveys, both wider and deeper, covering a large luminosity range are important to better understand LBG properties and their evolution.

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

2013-03-01

277

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

NASA Technical Reports Server (NTRS)

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

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

2012-01-01

278

Inversion with early photons.  

PubMed

Optical tomography using early photons can improve resolution and reduce the ill-posed nature of the inversion problem. In this work we use 360 degrees projection experimental data to investigate the inversion performance of three commonly used numerical inversion methods: the random algebraic reconstruction technique (rART), singular value decomposition (SVD), and the conjugate-gradient-type method LSQR. Results are contrasted to each other and the effects of different photon propagation models are also investigated. We find that all methods perform adequately given appropriate regularization parameters, and that an experimentally measured photon weight function yields superior results over two approximate weights that have been previously used. PMID:17500472

Turner, Gordon M; Soubret, Antoine; Ntziachristos, Vasilis

2007-04-01

279

Symmetry of Attractors and the KarhunenLo`eve Decomposition  

E-print Network

Symmetry of Attractors and the Karhunen­Lo`eve Decomposition Michael Dellnitz Department in the time­average of an appropriate observable such as the intensity of transmitted light in the Faraday] have investigated the Faraday surface wave model, looking for indications of pattern on average

Nicol, Matthew

280

Constrained Data Decomposition and Regression for Analyzing Healthy Aging from  

E-print Network

Constrained Data Decomposition and Regression for Analyzing Healthy Aging from Fiber Tract@sci.utah.edu Abstract. It has been shown that brain structures in normal aging un- dergo significant changes attributed aging will be necessary to explain differences to neurodegenera- tive patterns observed in mental

Prastawa, Marcel

281

Tremolite Decomposition and Water on Venus  

NASA Technical Reports Server (NTRS)

We present experimental data showing that the decomposition rate of tremolite, a hydrous mineral, is sufficiently slow that it can survive thermal decomposition on Venus over geologic timescales at current and higher surface temperatures.

Johnson, N. M.; Fegley, B., Jr.

2000-01-01

282

Crop residue decomposition in Minnesota biochar amended plots  

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

283

AVALANCHES, SANDPILES AND TUTTE DECOMPOSITION  

E-print Network

AVALANCHES, SANDPILES AND TUTTE DECOMPOSITION Andrei GABRIELOV Department of Geology, Cornell and avalanche models of failure were introduced recently (Bak et al., 1987, and an avalanche of publications properties of an important class of these models, Abelian sandpiles (Dhar, 1990) and Abelian avalanches

Gabrielov, Andrei

284

Exsolution by spinodal decomposition in multicomponent mineral solutions  

PubMed Central

Phase separation in a three-component system that results from the uphill diffusion of chemical components is considered. The binary decomposition model of Cahn and Hilliard is generalized to account for the interdiffusion of several chemical components with considerably different diffusion constants. Thereafter the decomposition dynamics and the phase relations of the final system state are investigated by means of finite-element modeling. Examples from a hypothetical regular solution and from ternary feldspar are addressed. Special attention is given to situations in which different diffusivities affect decomposition dynamics and the final system states. Good qualitative agreement between our modeling and petrographic observations on exsolved feldspar is achieved. Our model explains systematic deviations from equilibrium element partitioning between the two phases exsolving from an initially homogeneous ternary feldspar during slow cooling. PMID:23888123

Petrishcheva, E.; Abart, R.

2012-01-01

285

Investigating hydrogel dosimeter decomposition by chemical methods  

NASA Astrophysics Data System (ADS)

The chemical oxidative decomposition of leucocrystal violet micelle hydrogel dosimeters was investigated using the reaction of ferrous ions with hydrogen peroxide or sodium bicarbonate with hydrogen peroxide. The second reaction is more effective at dye decomposition in gelatin hydrogels. Additional chemical analysis is required to determine the decomposition products.

Jordan, Kevin

2015-01-01

286

DECOMPOSITION OF SEPARABLE CONCAVE STRUCTURING FUNCTIONS  

E-print Network

for proper discretization of the proposed decomposition scheme. In mathematical morphology [18, 7], concave this decomposition cannot be properly discretized, i.e. discretizing the tops and then dilating leads to a differentDECOMPOSITION OF SEPARABLE CONCAVE STRUCTURING FUNCTIONS R. VAN DEN BOOMGAARD, E.A. ENGBERS and A

Smeulders, Arnold

287

Error propagation in decomposition of Mueller matrices  

Microsoft Academic Search

A decomposition for Mueller matrices into three physically descriptive components was recently developed by Shih-Yau Lu. The effect of experimental error on this decomposition was studied. Both analytical and numerical methods were employed. Symbolic expression of the component matrices in terms of the original Mueller matrix elements shows how errors in the original matrix propagate through the decomposition. Complete symbolic

Diana M. Hayes

1997-01-01

288

FINITE ELEMENT DECOMPOSITION OF THE HUMAN NEOCORTEX  

E-print Network

FINITE ELEMENT DECOMPOSITION OF THE HUMAN NEOCORTEX A Thesis by SEELING CHOW Submitted Element Decomposition of the Human Neocortex. (May 1998) Seeling Chow, B.S., Texas A&M University Chair Advisory Committee: Dr. Bruce H. McCormick The finite element decomposition of the human neocortex provides

289

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

NASA Astrophysics Data System (ADS)

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

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

1989-12-01

290

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

SciTech Connect

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

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

2013-03-10

291

Refining signal decomposition for GRETINA detectors  

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

292

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

2013-01-01

293

Noisy matrix decomposition via convex relaxation: Optimal rates in high dimensions  

E-print Network

We analyze a class of estimators based on convex relaxation for solving high-dimensional matrix decomposition problems. The observations are noisy realizations of a linear transformation [bar through "X" symbol] of the sum ...

Agarwal, Alekh

294

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

PubMed

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

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

2010-11-01

295

Diagenetic processes near the sediment-water interface of Long Island Sound. I. Decomposition and nutrient element geochemistry (S,N,P)  

SciTech Connect

Selected early diagenetic reactions associated with the decomposition of organic matter in estuarine deposits of Long Island Sound are examined with particular emphasis on undstanding the role of benthic macroorganisms together with the depositional environment in controlling the decomposition of surface sediments and in determining the flux of solutes between sediment and overlying water.

Aller, R.C.

1980-12-01

296

Diagenetic Processes Near the Sediment-Water Interface of Long Island Sound.I. Decomposition and Nutrient Element Geochemistry (S, N, P)  

Microsoft Academic Search

Selected early diagenetic reactions associated with the decomposition of organic matter in estuarine deposits of Long Island Sound are examined with particular emphasis on undstanding the role of benthic macroorganisms together with the depositional environment in controlling the decomposition of surface sediments and in determining the flux of solutes between sediment and overlying water.

Robert C. Aller

1980-01-01

297

Molecular Beam Studies of Thermal Decomposition of Glycine on Solid Surfaces  

NASA Astrophysics Data System (ADS)

A molecular beam technique for studying the decomposition of vapor-phase glycine on solid surfaces has been developed. The decomposition probability of glycine on the surfaces of polycrystalline molybdenum oxide and glass was measured as a function of the surface temperature. Decomposition products were quantitatively analyzed with a mass spectrometer in the temperature range of 420-800 K. The probability of decomposition of glycine per one collision with molybdenum oxide was found to be almost unity at a high surface temperature (˜ 800 K), while that with glass was less than 0.15 in the observed temperature range. The values of activation energy E and the pre-exponential factor SZ2/Z1 for the decomposition are determined. A new model based on the transition state theory to evaluate the values of the pre-exponential factor is proposed.

Okude, Shin'ichiro; Matsushima, Fusakazu; Kuze, Hiroaki; Shimizu, Tadao

1987-04-01

298

Symptoms during the Menopausal Transition and Early Postmenopause and their Relation to Endocrine Levels over Time: Observations from the Seattle Midlife Women's Health Study  

E-print Network

1 Symptoms during the Menopausal Transition and Early Postmenopause and their Relation to Endocrine of the menopausal transition were included in the analyses. Results: Correlations between endocrine levels to different endocrine levels (FSH, E1G, and T). Sleep disruption #12;3 may be key to understanding

Percival, Don

299

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

PubMed

Electronic home monitoring for chronic heart failure is emerging as an available option to add to our armamentarium as a vital part of the multidisciplinary care process. This investigation describes the early clinical results of a multicenter study that suggests that important trends in medical resource utilization may be attained by the use of this modality. (c)2000 by CHF, Inc. PMID:12029180

Mehra, M R; Uber, P A; Chomsky, D B; Oren, R

2000-01-01

300

Summer and early-fall sea-ice concentration in the Ross Sea: comparison of in situ ASPeCt observations and satellite passive  

E-print Network

image processing on a subset of nine helicopter flights to obtain ice concentration on a continuous-sampling methods to characterize the ice cover; the `ASPeCt sampling' on the helicopter video and the useSummer and early-fall sea-ice concentration in the Ross Sea: comparison of in situ ASPe

Texas at San Antonio, University of

301

Development of rate expressions for the thermal decomposition of RDX  

SciTech Connect

Decomposition and combustion of energetic materials involve processes in both condensed and gas phases. Development of reliable models for design, performance, stability, and hazard analyses requires detailed understanding of the mechanisms for both the initial condensed phase decomposition of the energetic material and the subsequent reaction of the decomposition species to form the ultimate reaction products. Those mechanisms must be described in terms of constitutive rate expressions that can be incorporated into mathematical models. The thermal decomposition of RDX has been studied by Behrens and Bulusu using Simultaneous Thermogravimetric Modulated Beam Mass Spectrometry (STMBMS). Their work provides a basis for developing some of the constitutive rate expressions that are needed in models for design, performance, stability and hazard analyses involving RDX. Behrens and Bulusu have identified four primary reaction pathways that control the liquid-phase decomposition of RDX at temperatures between 200 and 215[degrees]C, and one that controls solid-phase decomposition at temperatures below 200[degrees]C. Two of the liquid-phase pathways appear to be first order in RDX. Arrhenius parameters for the first-order rate constants were evaluated from data reported by Behrens and Bulusu. Reaction rates extrapolated to temperatures between 370 and 450[degrees]C are in good agreement with global reaction rates observed by Trott et al. using high-speed photography and laser-heated thin-film samples. Furthermore, the STMBMS results of Behrens and Bulusu appear to be consistent with condensed-phase infrared results reported by Trott et al. and Erickson et al.

Erickson, K.L. (Sandia National Labs., Albuquerque, NM (United States)); Behrens, R. Jr. (Sandia National Labs., Livermore, CA (United States)); Bulusu, S. (Army Armament Research, Development and Engineering Center, Dover, NJ (United States))

1992-01-01

302

Development of rate expressions for the thermal decomposition of RDX  

SciTech Connect

Decomposition and combustion of energetic materials involve processes in both condensed and gas phases. Development of reliable models for design, performance, stability, and hazard analyses requires detailed understanding of the mechanisms for both the initial condensed phase decomposition of the energetic material and the subsequent reaction of the decomposition species to form the ultimate reaction products. Those mechanisms must be described in terms of constitutive rate expressions that can be incorporated into mathematical models. The thermal decomposition of RDX has been studied by Behrens and Bulusu using Simultaneous Thermogravimetric Modulated Beam Mass Spectrometry (STMBMS). Their work provides a basis for developing some of the constitutive rate expressions that are needed in models for design, performance, stability and hazard analyses involving RDX. Behrens and Bulusu have identified four primary reaction pathways that control the liquid-phase decomposition of RDX at temperatures between 200 and 215{degrees}C, and one that controls solid-phase decomposition at temperatures below 200{degrees}C. Two of the liquid-phase pathways appear to be first order in RDX. Arrhenius parameters for the first-order rate constants were evaluated from data reported by Behrens and Bulusu. Reaction rates extrapolated to temperatures between 370 and 450{degrees}C are in good agreement with global reaction rates observed by Trott et al. using high-speed photography and laser-heated thin-film samples. Furthermore, the STMBMS results of Behrens and Bulusu appear to be consistent with condensed-phase infrared results reported by Trott et al. and Erickson et al.

Erickson, K.L. [Sandia National Labs., Albuquerque, NM (United States); Behrens, R. Jr. [Sandia National Labs., Livermore, CA (United States); Bulusu, S. [Army Armament Research, Development and Engineering Center, Dover, NJ (United States)

1992-12-31

303

Ozone decomposition in water solutions  

E-print Network

. . . . . . . . . . . . . 75 III. CBI. iiICAT, OXYGEN DEMAND TEST. . IV. OIONE DECOI'IPOSITION DATA. . . . . V. COD DATA FOH THE CONTINUOUS ABSOHBER- REACTION SYSTEM VITA 78 8$ LIST OF TABLES TABI E PAGE I. OZONE DECOMPOSITION IN MATER SOLUTIONS. . . g4 Il. REACTION.... The spectrophotometric method was used since ozone molecules whicn are dissolved in an aqueous solution will maintain approximately the same adsorption maximum as they have in the gas phase. The iodometric method was used to determine the total concentration...

Hewes, Cecil Grayson

2012-06-07

304

On decompositions of multivariate functions  

Microsoft Academic Search

We present formulas that allow us to decompose a function f of d variables into a sum of 2^d terms f_{u} indexed by subsets u of {1,ldots,d} , where each term f_{u} depends only on the variables with indices in u . The decomposition depends on the choice of d commuting projections {P_j}_{j=1}^d , where P_j(f) does not depend on

F. Y. Kuo; I. H. Sloan; G. W. Wasilkowski; H. Wozniakowski

2010-01-01

305

Decomposition kinetics of plutonium hydride  

Microsoft Academic Search

Kinetic data for decomposition of PuH⁠ââ provides insight into a possible mechanism for the hydriding and dehydriding reactions of plutonium. The fact that the rate of the hydriding reaction, K\\/sub H\\/, is proportional to P¹² and the rate of the dehydriding process, K\\/sub D\\/, is inversely proportional to P¹² suggests that the forward and reverse reactions proceed by opposite

J. M. Haschke; J. L. Stakebake

1979-01-01

306

Phlogopite Decomposition, Water, and Venus  

NASA Technical Reports Server (NTRS)

Venus is a hot and dry planet with a surface temperature of 660 to 740 K and 30 parts per million by volume (ppmv) water vapor in its lower atmosphere. In contrast Earth has an average surface temperature of 288 K and 1-4% water vapor in its troposphere. The hot and dry conditions on Venus led many to speculate that hydrous minerals on the surface of Venus would not be there today even though they might have formed in a potentially wetter past. Thermodynamic calculations predict that many hydrous minerals are unstable under current Venusian conditions. Thermodynamics predicts whether a particular mineral is stable or not, but we need experimental data on the decomposition rate of hydrous minerals to determine if they survive on Venus today. Previously, we determined the decomposition rate of the amphibole tremolite, and found that it could exist for billions of years at current surface conditions. Here, we present our initial results on the decomposition of phlogopite mica, another common hydrous mineral on Earth.

Johnson, N. M.; Fegley, B., Jr.

2005-01-01

307

Decomposition-Based Decision Making for Aerospace Vehicle Design  

NASA Technical Reports Server (NTRS)

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

Borer, Nicholas K.; Mavris, DImitri N.

2005-01-01

308

The adsorption and decomposition of CO on Pt/111/.  

NASA Technical Reports Server (NTRS)

A cylindrical mirror electron energy analyzer has been used to study the adsorption and decomposition of CO on an initially clean Pt(111) surface. The observed rate of adsorption and fractional surface coverage as a function of CO exposure are identical to those observed previously in this laboratory by a flash filament adsorption technique. This result provides an absolute calibration of the Auger spectrometry system for carbon and oxygen. Beam-induced decomposition of CO was observed at high incident fluxes. The surface oxygen coverage decreased exponentially to zero during electron bombardment, while surface carbon decreased and then levelled off at a finite value. CO adsorption studies on this carbon contaminated surface showed decreasing CO adsorption rate and decreasing saturation coverage with increasing carbon contamination.

Martinez, J. M.; Hudson, J. B.

1973-01-01

309

Implementation of Domain Decomposition and Data Decomposition Algorithms in RMC code  

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

310

Sequence of Tissue Responses in the Early Stages of Experimental Allergic Encephalomyelitis (EAE): Immunohistochemical, Light Microscopic, and Ultrastructural Observations in the Spinal Cord  

NASA Technical Reports Server (NTRS)

Experimental allergic encephalomyelitis (EAE) was induced in adult Lewis rats with purified guinea pig CNS myelin and Freund's adjuvant. As soon as the very earliest clinical signs appeared the animals were perfused with fixatives and the spinal cord analyzed by electron microscopy, silver methods, and immunocytochemistry. Our findings suggest that in the early stages of EAE a sequence of events can be traced, although these events frequently overlap. The earliest morphological change appears to be astrocytic edema in both the cell body and processes. Increased amounts of glycogen particles and dispersion of glial filaments are prominent. These changes seem to occur just prior to the time when inflammatory cells begin to penetrate the capillary walls. Invasion of the neuropil mainly by macrophages and lymphocytes closely follows. Both macrophages and microglia seem to participate in phagocytosis of oligodendrocytes and myelin. Demyelination, however, is not a prominent feature at this early stage.

DAmelio, Fernando E.; Smith, Marion E.; Eng, Lawrence F.

1990-01-01

311

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

EPA Science Inventory

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

312

Molybdenum deposition from the decomposition of molybdenum hexacarbonyl  

SciTech Connect

Molybdenum metal deposition from the decomposition of Mo(CO)/sub 6/ adsorbed on Si(100), Mo, and Cu surfaces was studied by x-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy, thermal desorption spectroscopy, and low-energy electron diffraction. Pyrolytic, photolytic, and electron-induced Mo(CO)/sub 6/ decomposition were observed and indicated different dissociation mechanisms. Thermally decomposed Mo(CO)/sub 6/ was found to leave metallic Mo in the presence of C and O. Electron-induced decomposition resulted in the formation of molybdenum carbide on the surfaces. Ultraviolet (UV) irradiation of adsorbed Mo(CO)/sub 6/ induced new peaks in XPS and TDS spectra, suggesting the formation of an unsaturated molybdenum carbonyl adsorbate. Mo(CO)/sub 6/ was found to form a multilayer on these surfaces at low temperatures, and desorb with zero-order kinetics. Although both adsorbate desorption and decomposition took place when the samples were heated, desorption was the dominant reaction path. UV irradiation of gaseous and coadsorbed Mo(CO)/sub 6/ and O/sub 2/ was also investigated. UV irradiation of the gas-phase mixture leads to MoO/sub 2/ and MoO/sub 3/ deposition; however, UV irradiation of coadsorbed Mo(CO)/sub 6/ and O/sub 2/ resulted in unsaturated molybdenum carbonyl. The effects of annealing and Ar/sup +/ bombardment on the Mo-deposited Si(100) surface are also reported.

Cho, C.C.; Bernasek, S.L.

1989-04-15

313

Conductimetric determination of decomposition of silicate melts  

NASA Technical Reports Server (NTRS)

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

Kroeger, C.; Lieck, K.

1986-01-01

314

Decomposition and interpretation of Mueller matrices  

NASA Astrophysics Data System (ADS)

The various decompositions of depolarizing Mueller matrices into products of basic optical devices, i.e. retarders, diattenuators and depolarizers, are critically revisited. Both “classic” as well as recently proposed factorizations are overviewed. The “depolarization aspect” is given a special attention. Experimental matrices are factorized and physically interpreted using the different decompositions. The problems of physical realizability and matrix filtering are treated in connection with the sum decomposition of a depolarizing Mueller matrix.

Ossikovski, R.

2010-06-01

315

Finite Element Decomposition Of The Human Neocortex  

Microsoft Academic Search

Finite Element Decomposition of the Human Neocortex. (May 1998) Seeling Chow, B.S., Texas A&M University Chair Advisory Committee: Dr. Bruce H. McCormick The finite element decomposition of the human neocortex provides a structural information framework for the visualization and spatial organization of the neocortex at progressive levels of detail. The decomposition satisfies neuroanatomical consistency, a set of constraints defined by

Seeling Chow

1998-01-01

316

Thermodynamic anomaly in magnesium hydroxide decomposition  

SciTech Connect

The Origin of the discrepancy in the equilibrium water vapor pressure measurements for the reaction Mg(OH)/sub 2/(s) = MgO(s) + H/sub 2/O(g) when determined by Knudsen effusion and static manometry at the same temperature was investigated. For this reaction undergoing continuous thermal decomposition in Knudsen cells, Kay and Gregory observed that by extrapolating the steady-state apparent equilibrium vapor pressure measurements to zero-orifice, the vapor pressure was approx. 10/sup -4/ of that previously established by Giauque and Archibald as the true thermodynamic equilibrium vapor pressure using statistical mechanical entropy calculations for the entropy of water vapor. This large difference in vapor pressures suggests the possibility of the formation in a Knudsen cell of a higher energy MgO that is thermodynamically metastable by about 48 kJ / mole. It has been shown here that experimental results are qualitatively independent of the type of Mg(OH)/sub 2/ used as a starting material, which confirms the inferences of Kay and Gregory. Thus, most forms of Mg(OH)/sub 2/ are considered to be the stable thermodynamic equilibrium form. X-ray diffraction results show that during the course of the reaction only the equilibrium NaCl-type MgO is formed, and no different phases result from samples prepared in Knudsen cells. Surface area data indicate that the MgO molar surface area remains constant throughout the course of the reaction at low decomposition temperatures, and no significant annealing occurs at less than 400/sup 0/C. Scanning electron microscope photographs show no change in particle size or particle surface morphology. Solution calorimetric measurements indicate no inherent hgher energy content in the MgO from the solid produced in Knudsen cells. The Knudsen cell vapor pressure discrepancy may reflect the formation of a transient metastable MgO or Mg(OH)/sub 2/-MgO solid solution during continuous thermal decomposition in Knudsen cells.

Reis, T.A.

1983-08-01

317

Early Astronomy  

NASA Astrophysics Data System (ADS)

The earliest investigations that can be called scientific are concerned with the sky: they are the beginnings of astronomy. Many early civilizations produced astronomical texts, and several cultures that left no written records left monuments and artifacts-ranging from rock paintings to Stonehenge-that show a clear interest in astronomy. Civilizations in China, Mesopotamia, India and Greece had highly developed astronomies, and the astronomy of the Mayas was by no means negligible. Greek astronomy, as developed by the medieval Arab philosophers, evolved into the astronomy of Copernicus. This displaced the earth from the central stationary position that almost all earlier astronomies had assumed. Soon thereafter, in the first decades of the seventeenth century, Kepler found the true shape of the planetary orbits and Galileo introduced the telescope for astronomical observations.

Thurston, Hugh

318

Experimental validation of Mueller matrix differential decomposition.  

PubMed

Mueller matrix differential decomposition is a novel method for retrieving the polarimetric properties of general depolarizing anisotropic media [N. Ortega-Quijano and J. L. Arce-Diego, Opt. Lett. 36, 1942 (2011), R. Ossikovski, Opt. Lett. 36, 2330 (2011)]. The method has been verified for Mueller matrices available in the literature. We experimentally validate the decomposition for five different experimental setups with different commutation properties and controlled optical parameters, comparing the differential decomposition with the forward and reverse polar decompositions. The results enable to verify the method and to highlight its advantages for certain experimental applications of high interest. PMID:22274460

Ortega-Quijano, Noé; Haj-Ibrahim, Bicher; García-Caurel, Enric; Arce-Diego, José Luis; Ossikovski, Razvigor

2012-01-16

319

Nitrogen Addition Significantly Affects Forest Litter Decomposition under High Levels of Ambient Nitrogen Deposition  

PubMed Central

Background Forest litter decomposition is a major component of the global carbon (C) budget, and is greatly affected by the atmospheric nitrogen (N) deposition observed globally. However, the effects of N addition on forest litter decomposition, in ecosystems receiving increasingly higher levels of ambient N deposition, are poorly understood. Methodology/Principal Findings We conducted a two-year field experiment in five forests along the western edge of the Sichuan Basin in China, where atmospheric N deposition was up to 82–114 kg N ha–1 in the study sites. Four levels of N treatments were applied: (1) control (no N added), (2) low-N (50 kg N ha–1 year–1), (3) medium-N (150 kg N ha–1 year–1), and (4) high-N (300 kg N ha–1 year–1), N additions ranging from 40% to 370% of ambient N deposition. The decomposition processes of ten types of forest litters were then studied. Nitrogen additions significantly decreased the decomposition rates of six types of forest litters. N additions decreased forest litter decomposition, and the mass of residual litter was closely correlated to residual lignin during the decomposition process over the study period. The inhibitory effect of N addition on litter decomposition can be primarily explained by the inhibition of lignin decomposition by exogenous inorganic N. The overall decomposition rate of ten investigated substrates exhibited a significant negative linear relationship with initial tissue C/N and lignin/N, and significant positive relationships with initial tissue K and N concentrations; these relationships exhibited linear and logarithmic curves, respectively. Conclusions/Significance This study suggests that the expected progressive increases in N deposition may have a potential important impact on forest litter decomposition in the study area in the presence of high levels of ambient N deposition. PMID:24551152

Chen, Gang; Peng, Yong; Xiao, Yin-long; Hu, Ting-xing; Zhang, Jian; Li, Xian-wei; Liu, Li; Tang, Yi

2014-01-01

320

Mechanism change in hot dense liquid nitromethane decomposition: ReaxFF molecular dynamics simulations  

NASA Astrophysics Data System (ADS)

The decomposition mechanism of hot liquid nitromethane (NM) at various compressions and temperatures was studied using reactive force field (ReaxFF) molecular dynamics simulations. A competition between two initial thermal decomposition schemes is observed, depending on compression. At low densities unimolecular C-N bond cleavage is the dominant route, whereas when approaching Chapman-Jouget detonation conditions the dominant mechanism switches to the formation of CH3NO fragment. The change in decomposition mechanism of hot liquid NM leads to different kinetic and energetic behavior and products distribution.

Rom, Naomi; Zybin, Sergey; van Duin, Adri; Goddard, William; Zeiri, Yehuda; Katz, Gil; Kosloff, Ronnie

2011-06-01

321

Comparison of Serological Response to Doxycycline versus Benzathine Penicillin G in the Treatment of Early Syphilis in HIV-Infected Patients: A Multi-Center Observational Study  

PubMed Central

Background While doxycycline is recommended as an alternative treatment of syphilis in patients with penicillin allergy or intolerance, clinical studies to compare serological response to doxycycline versus benzathine penicillin in treatment of early syphilis among HIV-infected patients remain sparse. Methods We retrospectively reviewed the medical records of HIV-infected patients with early syphilis who received doxycycline 100 mg twice daily for 14 days (doxycycline group) and those who received 1 dose of benzathine penicillin (2.4 million units) (penicillin group) between 2007 and 2013. Serological responses defined as a decline of rapid plasma reagin titer by 4-fold or greater at 6 and 12 months of treatment were compared between the two groups. Results During the study period, 123 and 271 patients in the doxycycline and penicillin group, respectively, completed 6 months or longer follow-up. Ninety-one and 271 patients in the doxycycline and penicillin group, respectively, completed 12 months or longer follow-up. Clinical characteristics were similar between the two groups, except that, compared with penicillin group, doxycycline group had a lower proportion of patients with secondary syphilis (65.4% versus 41.5%, P<0.0001) and a higher proportion of patients with early latent syphilis (25.3% versus 49.6%, P<0.0001). No statistically significant differences were found in the serological response rates to doxycycline versus benzathine penicillin at 6 months (63.4% versus 72.3%, P?=?0.075) and 12 months of treatment (65.9% versus 68.3%, P?=?0.681). In multivariate analysis, secondary syphilis, but not treatment regimen, was consistently associated with serological response at 6 and 12 months of follow-up. Conclusions The serological response rates to a 14-day course of doxycycline and a single dose of benzathine penicillin were similar in HIV-infected patients with early syphilis at 6 and 12 months of follow-up. Patients with secondary syphilis were more likely to achieve serological response than those with other stages. PMID:25310367

Tsai, Jen-Chih; Lin, Yu-Huei; Lu, Po-Liang; Shen, Ni-Jiin; Yang, Chia-Jui; Lee, Nan-Yao; Tang, Hung-Jen; Liu, Yuag-Meng; Huang, Wen-Chi; Lee, Chen-Hsiang; Ko, Wen-Chien; Chen, Yen-Hsu; Lin, Hsi-Hsun; Chen, Tun-Chieh; Hung, Chien-Ching

2014-01-01

322

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

Microsoft Academic Search

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

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

1999-01-01

323

The Role of Endophytic Fungal Individuals and Communities in the Decomposition of Pinus massoniana Needle Litter  

PubMed Central

The role of fungal endophytes (FEs) as “pioneer” decomposers has recently been recognized; however, the extent to which FEs contribute to litter loss is less well understood. The genetic and enzymatic bases of FE-mediated decomposition have also rarely been addressed. The effects of populations and individuals (with an emphasis on two dominant Lophodermium taxa) of FEs on needle-litter decomposition were assessed for Pinus massoniana, a ubiquitous pine in southern China. Data from in vivo (microcosm) experiments indicated that the percentage of litter-mass loss triggered by FEs was linearly correlated with incubation time and approached 60% after seven months. In vitro decomposition tests also confirmed that endophytic Lophodermium isolates caused 14–22% mass loss within two months. Qualitative analysis of exoenzymes (cellulase and laccase, important for lignocellulose degradation) revealed that almost all of the Lophodermium isolates showed moderate or strong positive reactions. Furthermore, partial sequences of ?-glucosidase (glycoside hydrolase family 3, GH3), laccase, and cellobiohydrolase (GH7) genes were amplified from Lophodermium isolates as “functional markers” to evaluate their potential for lignocellulolytic activity. Three different genes were detected, suggesting a flexible and delicate decomposition system rich in FEs. Our work highlights the possibility that the saprophytism and endophytism of FEs may be prerequisites to initiating rapid decomposition and thus may be key in Fes’ contribution to litter decomposition, at least in the early stage. Potential indicators of the presence of core fungal decomposers are also briefly discussed. PMID:25157631

Yuan, Zhilin; Chen, Lianqing

2014-01-01

324

Thermal Decomposition of Radiation-Damaged Polystyrene  

SciTech Connect

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

J Abrefah GS Klinger

2000-09-26

325

Evidence of Inside-out Multi-stage Formation History in UV-bright Early Type Galaxies Observed in the Mid-IR  

NASA Astrophysics Data System (ADS)

The origin of significant UV emission in quiescent early type galaxies (ETGs) is currently still debated, and strongly tied to a multi-epoch evolutionary process where much of the information is lost after progressing well beyond relaxation timescales. In order to address this topic, stellar synthesis and galaxy evolution must be disentangled, which can be more pragmatically done with well-resolved multi-wavelength images of nearby ETGs. We explore the radial distribution of FUV-NUV, NUV-r, and NUV-IR colors (GALEX, SDSS, and WISE) in a selection of nearby E/S0-type galaxies. Comparing these colors with stellar synthesis models, we find strong color gradients with the outer radii bluer than the inner half-light radii by ~1 magnitude, and account for it with an extreme horizontal branch fraction increase of 0.25 with radius. We estimated the average ages and determine that outer regions are likely to have formed ~1 Gyr after the inner regions. The results support inside-out formation: rapid star formation within the core at early epochs (>4 Gyr ago) and at least one later stage starburst event coinciding with 1.

Petty, Sara M.; Neill, J. D.; Jarrett, T.; Blain, A.; Farrah, D.; Rich, R. M.; Tsai, C.; Benford, D. J.; Bridge, C.; Lake, S. E.; Masci, F. J.; Wright, E. L.; WISE

2014-01-01

326

Balanced Model Reduction via the Proper Orthogonal Decomposition  

Microsoft Academic Search

A new method for performing a balanced reduction of a high-order linear system is presented. The technique combines the proper orthogonal decomposition and concepts from balanced realization theory. The method of snapshotsisused to obtainlow-rank,reduced-rangeapproximationsto thesystemcontrollability and observability grammiansineitherthetimeorfrequencydomain.Theapproximationsarethenusedtoobtainabalancedreduced- order model. The method is particularly effective when a small number of outputs is of interest. It is demonstrated for a linearized

K. Willcoxand; J. Peraire

2002-01-01

327

Separable States with Unique Decompositions  

NASA Astrophysics Data System (ADS)

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

Ha, Kil-Chan; Kye, Seung-Hyeok

2014-05-01

328

Arlequin based PGD domain decomposition  

NASA Astrophysics Data System (ADS)

Problems defined in fully or partially separable domains can be solved by considering a space separated representation of the unknown fields. Thus three-dimensional problems can be solved from the solution of some one-dimensional problems in the case of fully separated representations involving the three space coordinates or as a sequence of 2D and 1D problems in the case of partially separated representations (plates, shells or extruded geometries). When the domains become more complex, sometimes they can be simplified by using appropriate mappings. When it is not possible or such a transformation becomes too complex, the use of domain decomposition could facilitate the use of separated representations. However, domain coupling in the context of space separated representations have never been analyzed. In this paper we propose a domain decomposition strategy based on the use of space separated representations and the Arlequin coupling strategy. First we consider separated representations of the physical space that will be then extended to address parametric solutions.

Nazeer, S. Mohamed; Bordeu, Felipe; Leygue, Adrien; Chinesta, Francisco

2014-11-01

329

Mössbauer study of ferric oxide particles as products of thermal decomposition of iron\\/III\\/benzoate  

Microsoft Academic Search

The products of the thermal decomposition in air of iron\\/III\\/benzoate [Fe3\\/C6H5COO\\/6\\/OH\\/2]OH.H2O have been studied using conventional thermal analysis, X-ray diffraction measurements and mainly Mössbauer spectroscopy. The decomposition occurs in the temperature range 200–350°C. It was possible to identify benzoic acid and ferric oxide as final products. Above 300°C, the observed ferric oxide showed a particle size distribution, which depends on

A. Abras; M. M. Braga; J. C. Machado

1984-01-01

330

Formation of thermal decomposition cavities in physical vapor transport of silicon carbide  

Microsoft Academic Search

The relationship between seed mounting and the formation of thermal decomposition cavities in physical vapor transport grown\\u000a silicon carbide was investigated. Scanning electron microscopy, energy dispersive x-ray spectroscopy, Auger electron spectroscopy,\\u000a and optical microscopy were used to characterize thermal decomposition cavities at various stages of their development. The\\u000a observations indicate that the attachment layer that holds the seed to the

Edward K. Sanchez; Thomas Kuhr; Volker D. Heydemann; David W. Snyder; Gregory S. Rohrer; Marek Skowronski

2000-01-01

331

Use of polar decomposition for the diagnosis of oral precancer  

NASA Astrophysics Data System (ADS)

The Mueller matrix describes all the polarizing properties of a sample and, therefore, the optical differences between noncancerous and precancerous tissue that may be present within the matrix elements. A high-speed polarimetry system that generates 16 (4×4) full Mueller matrices to characterize tissues is presented. Feature extraction is done on the Mueller matrix elements resulting in depolarization and retardance images by polar decomposition. These are used to detect and classify early oral cancers and precancerous changes in epithelium such as dysplasia. These images are compared with orthogonal polarization images and analyzed in an attempt to identity useful factors for the differentiation between cancerous lesions and their benign counterparts. Our results indicate that polarimetry has potential as a method for the in vivo early detection and diagnosis of oral premalignancy.

Chung, Jungrae; Jung, Woonggyu; Hammer-Wilson, Marie J.; Wilder-Smith, Petra; Chen, Zhongping

2007-05-01

332

Use of polar decomposition for the diagnosis of oral precancer.  

PubMed

The Mueller matrix describes all the polarizing properties of a sample and, therefore, the optical differences between noncancerous and precancerous tissue that may be present within the matrix elements. A high-speed polarimetry system that generates 16 (4x4) full Mueller matrices to characterize tissues is presented. Feature extraction is done on the Mueller matrix elements resulting in depolarization and retardance images by polar decomposition. These are used to detect and classify early oral cancers and precancerous changes in epithelium such as dysplasia. These images are compared with orthogonal polarization images and analyzed in an attempt to identity useful factors for the differentiation between cancerous lesions and their benign counterparts. Our results indicate that polarimetry has potential as a method for the in vivo early detection and diagnosis of oral premalignancy. PMID:17514255

Chung, Jungrae; Jung, Woonggyu; Hammer-Wilson, Marie J; Wilder-Smith, Petra; Chen, Zhongping

2007-05-20

333

Summer and early-fall sea-ice concentration in the Ross Sea: comparison of in situ ASPeCt observations and satellite passive microwave estimates  

Microsoft Academic Search

Sea-ice conditions were observed using the ASPeCt observation protocol on three cruises in the Ross Sea spanning the Antarctic summer season (APIS, December 1999-February 2000; AnSlope 1, March-April 2003; AnSlope 2, February-April 2004). An additional dataset was analyzed from helicopter video surveys taken during the APIS cruise. The helicopter video was analyzed using two techniques: first, as an ASPeCt dataset

Margaret A. Knuth; Stephen F. Ackley

2006-01-01

334

Modular polynomial arithmetic in partial fraction decomposition  

NASA Technical Reports Server (NTRS)

Algorithms for general partial fraction decomposition are obtained by using modular polynomial arithmetic. An algorithm is presented to compute inverses modulo a power of a polynomial in terms of inverses modulo that polynomial. This algorithm is used to make an improvement in the Kung-Tong partial fraction decomposition algorithm.

Abdali, S. K.; Caviness, B. F.; Pridor, A.

1977-01-01

335

Polyhedral Surface Decomposition with Applications EMANOIL ZUCKERBERGER  

E-print Network

two decomposition algorithms ­ flooding convex de- composition and watershed decomposition, and show (i.e., convexity). Watershed segmentation algorithms segment a given object into "catchment basins of polyhedra into solids has been a lively topic of research in computational geometry. It is generally

Tal, Ayellet

336

Proper Orthogonal Decomposition for Flow Calculations  

E-print Network

Proper Orthogonal Decomposition for Flow Calculations and Optimal Control in a Horizontal CVD North Carolina State University Raleigh, NC 27695­8205 USA March 23, 1998 Abstract Proper orthogonal orthogonal decomposition (POD) is an optimal tech­ nique of finding a basis which spans an ensemble of data

337

Decomposition and interpretation of Mueller matrices  

Microsoft Academic Search

The various decompositions of depolarizing Mueller matrices into products of basic optical devices, i.e. retarders, diattenuators and depolarizers, are critically revisited. Both ``classic'' as well as recently proposed factorizations are overviewed. The ``depolarization aspect'' is given a special attention. Experimental matrices are factorized and physically interpreted using the different decompositions. The problems of physical realizability and matrix filtering are treated

R. Ossikovski

2010-01-01

338

Review of human decomposition processes in soil  

Microsoft Academic Search

In-soil human decomposition is comprehensively described in terms of the physico-chemical and bacterial environmental conditions. Much of the understanding comes from considerations of cemetery studies and experimentation with adipocere. The understandings are relevant for further studies in cemetery management, exhumations, forensic investigations and anthropology. In the soil, cadavers are subject to various sets of decomposition processes principally resulting from aerobic

B. B. Dent; S. L. Forbes; B. H. Stuart

2004-01-01

339

9 CFR 381.93 - Decomposition.  

Code of Federal Regulations, 2014 CFR

...2014-01-01 2014-01-01 false Decomposition. 381.93 Section 381.93 Animals...of Carcasses and Parts § 381.93 Decomposition. Carcasses of poultry deleteriously...superficial in nature may be passed for human food after removal and...

2014-01-01

340

9 CFR 381.93 - Decomposition.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Decomposition. 381.93 Section 381.93 Animals...of Carcasses and Parts § 381.93 Decomposition. Carcasses of poultry deleteriously...superficial in nature may be passed for human food after removal and...

2012-01-01

341

HIERARCHICAL DECOMPOSITION OF DOMAINS WITH FRACTURES  

E-print Network

HIERARCHICAL DECOMPOSITION OF DOMAINS WITH FRACTURES SUSANNA GEBAUER, RALF KORNHUBER, AND HARRY. Similar problems occur in other applications: The heat transfer in the human body is dominated 1806/2­1 and Ko 1806/2­3 . 1 #12; 2 GEBAUER, KORNHUBER, AND YSERENTANT decomposition methods (HDD

Kornhuber, Ralf

342

DECOMPOSITIONAL ODOR ANALYSIS DATABASE - PHASE I  

Microsoft Academic Search

This study, conducted at the University of Tennessee's Anthropological Research Facility (ARF), describes the development of the Decompositional Odor Analysis (D.O.A.) Database and seeks to establish the chemical basis for canine's scenting ability when detecting human remains. This database is composed of chemicals that are liberated during the decompositional process from buried human remains. This 'living' database currently spans the

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

343

9 CFR 381.93 - Decomposition.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Decomposition. 381.93 Section 381.93 Animals...of Carcasses and Parts § 381.93 Decomposition. Carcasses of poultry deleteriously...superficial in nature may be passed for human food after removal and...

2013-01-01

344

HIERARCHICAL DECOMPOSITION OF DOMAINS WITH FRACTURES  

E-print Network

HIERARCHICAL DECOMPOSITION OF DOMAINS WITH FRACTURES SUSANNA GEBAUER, RALF KORNHUBER, AND HARRY problems occur in other applications: The heat transfer in the human body is dominated by the blood vessels, AND YSERENTANT hierarchical domain decomposition methods. The basic idea is to decompose the discrete solution

Kornhuber, Ralf

345

9 CFR 381.93 - Decomposition.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Decomposition. 381.93 Section 381.93 Animals...of Carcasses and Parts § 381.93 Decomposition. Carcasses of poultry deleteriously...superficial in nature may be passed for human food after removal and...

2010-01-01

346

9 CFR 381.93 - Decomposition.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 2011-01-01 false Decomposition. 381.93 Section 381.93 Animals...of Carcasses and Parts § 381.93 Decomposition. Carcasses of poultry deleteriously...superficial in nature may be passed for human food after removal and...

2011-01-01

347

Sampling Stoichiometry: The Decomposition of Hydrogen Peroxide.  

ERIC Educational Resources Information Center

Describes a demonstration of the decomposition of hydrogen peroxide to provide an interesting, quantitative illustration of the stoichiometric relationship between the decomposition of hydrogen peroxide and the formation of oxygen gas. This 10-minute demonstration uses ordinary hydrogen peroxide and yeast that can be purchased in a supermarket.…

Clift, Philip A.

1992-01-01

348

The disjunctive decomposition of logic functions  

Microsoft Academic Search

We present an algorithm for extracting a disjunctive decomposition from the BDD representation of a logic function F. The output of the algorithm is a multiple-level netlist exposing the hierarchical decomposition structure of the function. The algorithm has theoretical quadratic complexity in the size of the input BDD. Experimentally, we were able to decompose most synthesis benchmarks in less than

Valeria Bertacco; Maurizio Damiani

1997-01-01

349

Balanced 0 1 Matrices Part I: Decomposition  

E-print Network

Balanced 0 1 Matrices Part I: Decomposition Michele Conforti Gerard Cornuejols y Ajai Kapoor z and Kristina Vuskovic x revised September 2000 Abstract A 0 1 matrix is balanced if, in every square submatrix extends the decomposition of balanced 0 1 matrices obtained by Conforti, Cornuejols and Rao to the class

Cornuejols, Gerard P.

350

Generalized covariation and extended Fukushima decompositions for Banach valued processes.  

E-print Network

Generalized covariation and extended Fukushima decompositions for Banach valued processes corresponding results when B = C([-, 0]) and X = X(·). This will consitute a significant Fukushima decomposition random variables, Malliavin calculus, Generalized Fukushima decomposition. LUISS Guido Carli - Libera

Paris-Sud XI, Université de

351

Tracking the Consequences of Morpho-Orthographic Decomposition Using ERPs  

PubMed Central

We examined the effects of morpho-orthographic decomposition on complex word processing using a combination of masked priming and ERP recordings. The process of morpho-orthographic decomposition was primed by the prior presentation of complex non-words (formed by the combination a legal stem and legal affix, e.g. huntity, cornity, scanity) as prime stimuli. Targets were semantically transparent complex words (e.g. hunter), semantically opaque pseudocomplex words (e.g. corner), and simplex words (e.g. scandal) that contained the same stem as primes or a different stem (e.g., huntity-hunter vs. farmity-hunter). We found a large early (150–200 ms) priming effect for transparent complex words only, followed by widely distributed priming effects between 200 and 300 ms and more spatially focused N400 priming effects for all types of target. Furthermore, in the 150–200 ms time-window, the ERP waveforms generated by pseudocomplex words patterned with those of complex words, both of which generated less negative-going waveforms compared with simplex words. In the N400 time-window, on the other hand, complex words differed from both pseudocomplex and simplex words. The results provide further support for early morpho-orthographic segmentation processes that operate independently of semantic transparency, and suggest that the output of these processes only affects the subsequent processing of truly complex words. PMID:23872217

Morris, Joanna; Grainger, Jonathan; Holcomb, Phillip J.

2013-01-01

352

Effects of heating rate, temperature and iron catalysis on the thermal behaviour and decomposition of 2-nitrobenzoyl chloride.  

PubMed

Runaway reactions arising from the decomposition of thermally unstable materials are a concern in industry due to the potentially devastating effects that they yield. Studies into the occurrence of thermal runaway incidents have shown the most likely cause to be a result of an inadequate investigation of the process prior to its operation on a large-scale. The chlorination of ortho-nitrated carboxylic acids is an industrially important reaction in the fine and agrochemical industries. The products of these reactions, ortho-nitrated acid chlorides, have been involved in runaway incidents that have resulted in violent explosions; hence, their thermal stability must be studied. Previous studies [S.D. Lever, M. Papadaki, Study of condition-dependent decomposition reactions: the thermal behaviour and decomposition of 2-nitrobenzoyl chloride, Part I, J. Hazard. Mater. 115 (2004) 91-100] showed that the decomposition of the parent molecule, 2-nitrobenzoyl chloride, is highly condition-dependent with the sample heating rate and temperature of decomposition playing a preponderant role in the course of the decomposition. Here, we present the results of studies of the decomposition of 2-nitrobenzoyl chloride, when the sample is subjected to various heating treatments, temperatures and in the presence of iron. As the temperature of decomposition was increased from 150 to 162 degrees C, the heat of decomposition was reduced from -215 to -90 kJ/mol. As the heat up rate applied in bringing the sample to the decomposition temperature increased, the heat of decomposition also increased. An increase in the heat up rate from 2 to 7.5 degrees C/min resulted in an increase in the heat of decomposition from -90 to -215 kJ/mol. The presence of iron and silver was observed to lower the heat of decomposition from -185 to -160 and -110 kJ/mol, respectively. Under most conditions investigated, the temperature at which gas flow was initiated was 147-150 degrees C. The presence of iron reduced this temperature to 140 degrees C. Decomposition was observed to take place over two stages, where the sample was heated directly from 40 degrees C at the required heat up rate. Where the sample was heated in stages and where calibrations had been carried out preceding decomposition, the decomposition took place in one stage alone. PMID:16236442

Lever, Sarah D; Papadaki, Maria

2006-03-17

353

Regarding the Potential Impact of Double Star Observations on Conceptions of the Universe of Stars in the Early 17TH Century  

E-print Network

Galileo Galilei believed that stars were distant suns whose sizes measured via his telescope were a direct indication of distance -- fainter stars (appearing smaller in the telescope) being farther away than brighter ones. Galileo argued in his Dialogue that telescopic observation of a chance alignment of a faint (distant) and bright (closer) star would reveal annual parallax, if such double stars were found. This would provide support both for Galileo's ideas concerning the nature of stars and for the motion of the Earth. However, Galileo actually made observations of such double stars, well before publication of the Dialogue. We show that the results of these observations, and the likely results of observations of any double star that was a viable subject for Galileo's telescope, would undermine Galileo's ideas, not support them. We argue that such observations would lead either to the more correct idea that stars were sun-like bodies of varying sizes which could be physically grouped, or to the less correc...

Graney, Christopher M

2008-01-01

354

Multilinear operators for higher-order decompositions.  

SciTech Connect

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

Kolda, Tamara Gibson

2006-04-01

355

Catalytic Decomposition of Organophosphorus Compounds  

NASA Astrophysics Data System (ADS)

Organophosphorus compounds have several applications (agricultural, industrial, and military). Nevertheless, assessments of the hazards from these applications quite often do not take into account chemical processes during their interactions with environment. The management of contaminants requires considerable knowledge and understanding of contaminant behavior. Unique properties of clay minerals and metal oxides, such as high adsorption and catalytic ability, have resulted in their applications as natural adsorbents and catalysts in the development of cleanup technologies. Knowledge of molecular structure, transformation mechanisms, and the spectrum of potential intermediates/products of the contaminant decomposition is helpful for developing remediation processes. An understanding of the physical characteristics of the adsorption sites of selected soil ingredients, the physical and chemical characteristics of the contaminant, details of sorption of contaminants on soil and in water solution, and also their distribution within the environment is of particular interest. Application of computational chemistry (CC) can provide deeper insight into the aforementioned characteristics of organophosphorus compounds.

Michalkova, A.; Leszczynski, J.

356

MAGIC gamma-ray and multi-frequency observations of flat spectrum radio quasar PKS 1510-089 in early 2012  

NASA Astrophysics Data System (ADS)

Aims: Amongst more than fifty blazars detected in very high energy (VHE, E> 100 GeV) ? rays, only three belong to the subclass of flat spectrum radio quasars (FSRQs). The detection of FSRQs in the VHE range is challenging, mainly because of their soft spectra in the GeV-TeV regime. MAGIC observed PKS 1510-089 (z = 0.36) starting 2012 February 3 until April 3 during a high activity state in the high energy (HE, E> 100 MeV) ?-ray band observed by AGILE and Fermi. MAGIC observations result in the detection of a source with significance of 6.0 standard deviations (?). We study the multi-frequency behaviour of the source at the epoch of MAGIC observation, collecting quasi-simultaneous data at radio and optical (GASP-WEBT and F-Gamma collaborations, REM, Steward, Perkins, Liverpool, OVRO, and VLBA telescopes), X-ray (Swift satellite), and HE ?-ray frequencies. Methods: We study the VHE ?-ray emission, together with the multi-frequency light curves, 43 GHz radio maps, and spectral energy distribution (SED) of the source. The quasi-simultaneous multi-frequency SED from the millimetre radio band to VHE ? rays is modelled with a one-zone inverse Compton model. We study two different origins of the seed photons for the inverse Compton scattering, namely the infrared torus and a slow sheath surrounding the jet around the Very Long Baseline Array (VLBA) core. Results: We find that the VHE ?-ray emission detected from PKS 1510-089 in 2012 February-April agrees with the previous VHE observations of the source from 2009 March-April. We find no statistically significant variability during the MAGIC observations on daily, weekly, or monthly time scales, while the other two known VHE FSRQs (3C 279 and PKS 1222+216) have shown daily scale to sub-hour variability. The ?-ray SED combining AGILE, Fermi and MAGIC data joins smoothly and shows no hint of a break. The multi-frequency light curves suggest a common origin for the millimetre radio and HE ?-ray emission, and the HE ?-ray flaring starts when the new component is ejected from the 43 GHz VLBA core and the studied SED models fit the data well. However, the fast HE ?-ray variability requires that within the modelled large emitting region, more compact regions must exist. We suggest that these observed signatures would be most naturally explained by a turbulent plasma flowing at a relativistic speed down the jet and crossing a standing conical shock.

Aleksi?, J.; Ansoldi, S.; Antonelli, L. A.; Antoranz, P.; Babic, A.; Bangale, P.; Barres de Almeida, U.; Barrio, J. A.; Becerra González, J.; Bednarek, W.; Bernardini, E.; Biland, A.; Blanch, O.; Bonnefoy, S.; Bonnoli, G.; Borracci, F.; Bretz, T.; Carmona, E.; Carosi, A.; Carreto Fidalgo, D.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Covino, S.; Da Vela, P.; Dazzi, F.; De Angelis, A.; De Caneva, G.; De Lotto, B.; Delgado Mendez, C.; Doert, M.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Einecke, S.; Eisenacher, D.; Elsaesser, D.; Farina, E.; Ferenc, D.; Fonseca, M. V.; Font, L.; Frantzen, K.; Fruck, C.; García López, R. J.; Garczarczyk, M.; Garrido Terrats, D.; Gaug, M.; Godinovi?, N.; González Muñoz, A.; Gozzini, S. R.; Hadasch, D.; Hayashida, M.; Herrera, J.; Herrero, A.; Hildebrand, D.; Hose, J.; Hrupec, D.; Idec, W.; Kadenius, V.; Kellermann, H.; Kodani, K.; Konno, Y.; Krause, J.; Kubo, H.; Kushida, J.; La Barbera, A.; Lelas, D.; Lewandowska, N.; Lindfors, E.; Lombardi, S.; López, M.; López-Coto, R.; López-Oramas, A.; Lorenz, E.; Lozano, I.; Makariev, M.; Mallot, K.; Maneva, G.; Mankuzhiyil, N.; Mannheim, K.; Maraschi, L.; Marcote, B.; Mariotti, M.; Martínez, M.; Mazin, D.; Menzel, U.; Meucci, M.; Miranda, J. M.; Mirzoyan, R.; Moralejo, A.; Munar-Adrover, P.; Nakajima, D.; Niedzwiecki, A.; Nilsson, K.; Nishijima, K.; Noda, K.; Nowak, N.; Orito, R.; Overkemping, A.; Paiano, S.; Palatiello, M.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Paredes-Fortuny, X.; Partini, S.; Persic, M.; Prada, F.; Prada Moroni, P. G.; Prandini, E.; Preziuso, S.; Puljak, I.; Reinthal, R.; Rhode, W.; Ribó, M.; Rico, J.; Rodriguez Garcia, J.; Rügamer, S.; Saggion, A.; Saito, T.; Saito, K.; Satalecka, K.; Scalzotto, V.; Scapin, V.; Schultz, C.; Schweizer, T.; Shore, S. N.; Sillanpää, A.; Sitarek, J.; Snidaric, I.; Sobczynska, D.; Spanier, F.; Stamatescu, V.; Stamerra, A.; Steinbring, T.; Storz, J.; Strzys, M.; Sun, S.; Suri?, T.; Takalo, L.; Takami, H.; Tavecchio, F.; Temnikov, P.; Terzi?, T.; Tescaro, D.; Teshima, M.; Thaele, J.; Tibolla, O.; Torres, D. F.; Toyama, T.; Treves, A.; Uellenbeck, M.; Vogler, P.; Wagner, R. M.; Zandanel, F.; Zanin, R.

2014-09-01

357

Laparoscopic versus Open Liver Resection: Differences in Intraoperative and Early Postoperative Outcome among Cirrhotic Patients with Hepatocellular Carcinoma—A Retrospective Observational Study  

PubMed Central

Introduction. Laparoscopic liver resection is considered risky in cirrhotic patients, even if minor surgical trauma of laparoscopy could be useful to prevent deterioration of a compromised liver function. This study aimed to identify the differences in terms of perioperative complications and early outcome in cirrhotic patients undergoing minor hepatic resection for hepatocellular carcinoma with open or laparoscopic technique. Methods. In this retrospective study, 156 cirrhotic patients undergoing liver resection for hepatocellular carcinoma were divided into two groups according to type of surgical approach: laparoscopy (LS group: 23 patients) or laparotomy (LT group: 133 patients). Perioperative data, mortality, and length of hospital stay were recorded. Results. Groups were matched for type of resection, median number of nodules, and median diameter of largest lesions. Groups were also homogeneous for preoperative liver and renal function tests. Intraoperative haemoglobin decrease and transfusions of red blood cells and fresh frozen plasma were significantly lower in LS group. MELD score lasted stable after laparoscopic resection, while it increased in laparotomic group. Postoperative liver and renal failure and mortality were all lower in LS group. Conclusions. Lower morbidity and mortality, maintenance of liver function, and shorter hospital stay suggest the safety and benefit of laparoscopic approach. PMID:25548432

Siniscalchi, Antonio; Tarozzi, Giulia; Cipolat, Lucia; Pinna, Antonio D.; Faenza, Stefano

2014-01-01

358

Moisture can be the dominant environmental parameter governing cadaver decomposition in soil.  

PubMed

Forensic taphonomy involves the use of decomposition to estimate postmortem interval (PMI) or locate clandestine graves. Yet, cadaver decomposition remains poorly understood, particularly following burial in soil. Presently, we do not know how most edaphic and environmental parameters, including soil moisture, influence the breakdown of cadavers following burial and alter the processes that are used to estimate PMI and locate clandestine graves. To address this, we buried juvenile rat (Rattus rattus) cadavers (approximately 18 g wet weight) in three contrasting soils from tropical savanna ecosystems located in Pallarenda (sand), Wambiana (medium clay), or Yabulu (loamy sand), Queensland, Australia. These soils were sieved (2mm), weighed (500 g dry weight), calibrated to a matric potential of -0.01 megapascals (MPa), -0.05 MPa, or -0.3 MPa (wettest to driest) and incubated at 22 degrees C. Measurements of cadaver decomposition included cadaver mass loss, carbon dioxide-carbon (CO(2)-C) evolution, microbial biomass carbon (MBC), protease activity, phosphodiesterase activity, ninhydrin-reactive nitrogen (NRN) and soil pH. Cadaver burial resulted in a significant increase in CO(2)-C evolution, MBC, enzyme activities, NRN and soil pH. Cadaver decomposition in loamy sand and sandy soil was greater at lower matric potentials (wetter soil). However, optimal matric potential for cadaver decomposition in medium clay was exceeded, which resulted in a slower rate of cadaver decomposition in the wettest soil. Slower cadaver decomposition was also observed at high matric potential (-0.3 MPa). Furthermore, wet sandy soil was associated with greater cadaver decomposition than wet fine-textured soil. We conclude that gravesoil moisture content can modify the relationship between temperature and cadaver decomposition and that soil microorganisms can play a significant role in cadaver breakdown. We also conclude that soil NRN is a more reliable indicator of gravesoil than soil pH. PMID:20400249

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

2010-07-15

359

Formation of thermal decomposition cavities in physical vapor transport of silicon carbide  

SciTech Connect

The relationship between seed mounting and the formation of thermal decomposition cavities in physical vapor transport grown silicon carbide was investigated. Scanning electron microscopy, energy dispersive x-ray spectroscopy, Auger electron spectroscopy, and optical microscopy were used to characterize thermal decomposition cavities at various stages of their development. The observations indicate that the attachment layer that holds the seed to the graphite crucible lid frequently contains voids. The seed locally decomposes at void locations and Si-bearing species are transported through the void. The decomposition produces a cavity in the seed; the silicon is deposited on and diffuses into the graphite lit. The formation of thermal decomposition cavities can be suppressed by the application of a diffusion barrier on the seed crystal backside.

Sanchez, E.K.; Kuhr, T.; Heydemann, V.D.; Snyder, D.W.; Rohrer, G.S.; Skowronski, M.

2000-03-01

360

Formation of thermal decomposition cavities in physical vapor transport of silicon carbide  

NASA Astrophysics Data System (ADS)

The relationship between seed mounting and the formation of thermal decomposition cavities in physical vapor transport grown silicon carbide was investigated. Scanning electron microscopy, energy dispersive x-ray spectroscopy, Auger electron spectroscopy, and optical microscopy were used to characterize thermal decomposition cavities at various stages of their development. The observations indicate that the attachment layer that holds the seed to the graphite crucible lid frequently contains voids. The seed locally decomposes at void locations and Si-bearing species are transported through the void. The decomposition produces a cavity in the seed; the silicon is deposited on and diffuses into the graphite lid. The formation of thermal decomposition cavities can be suppressed by the application of a diffusion barrier on the seed crystal backside.

Sanchez, Edward K.; Kuhr, Thomas; Heydemann, Volker D.; Snyder, David W.; Rohrer, Gregory S.; Skowronski, Marek

2000-03-01

361

Integration of Observational and Analytical Methodologies to Characterize Organic Matter in Early Archaean Rocks: Distinguishing Biological from Abiotically Synthesized Carbonaceous Matter Structures  

Microsoft Academic Search

\\u000a Transmission Electron Microscopy (TEM) was applied to observe and characterize carbonaceous materials (CM) extracted from\\u000a black cherts and argillite in drill core from the Warrawoona Group of the Pilbara Craton, Western Australia. The black chert\\u000a came from a ‘white smoker type’ seafloor deposit in the ca. 3.49 Ga Dresser Formation, whereas the black argillites were obtained\\u000a from the 3.46 Ga

Miryam Glikson; Arthur H. Hickman; Lawrence J. Duck; Suzanne D. Golding; Robyn E. Webb

362

Relationship between skin barrier function in early neonates and diaper dermatitis during the first month of life: a prospective observational study.  

PubMed

Diaper dermatitis, a common skin problem in newborn infants, is characterized by poor functioning of the skin barrier. This study aimed to elucidate the relationship between skin barrier function in 4-day-old infants and the occurrence of diaper dermatitis during the first month of life. We recruited healthy Japanese infants born at 35 weeks of gestation or more. We measured indicators of skin barrier function, namely skin pH and transepidermal water loss, in 4-day-old infants on four places on the body. Individual characteristics were recorded from the infants' medical charts. The presence of diaper dermatitis was judged using the diaper rash and erythema scoring scale, which was based on daily recording of the infants' skin condition by their parents. The parents also filled out a questionnaire 1 month after birth regarding stool frequency and certain external factors. The association between diaper dermatitis and skin barrier function was assessed using multiple logistic regression analysis. The analysis included 88 infants. The incidence of diaper dermatitis was 25.0%. After adjusting for stool frequency for 1 month we noted that high pH on the inner arm skin in 4-day-old infants increased the risk of diaper dermatitis during the first month of life (adjusted odds ratio 3.35 [95% confidence interval = 1.12, 10.04]). Early neonatal skin pH may predict the risk of diaper dermatitis during the first month of life. Our results may be useful in devising strategies to prevent diaper dermatitis. PMID:25209731

Yonezawa, Kaori; Haruna, Megumi; Shiraishi, Mie; Matsuzaki, Masayo; Sanada, Hiromi

2014-01-01

363

THE SCHMIDT-KENNICUTT LAW OF MATCHED-AGE STAR-FORMING REGIONS; Pa{alpha} OBSERVATIONS OF THE EARLY-PHASE INTERACTING GALAXY TAFFY I  

SciTech Connect

In order to test a recent hypothesis that the dispersion in the Schmidt-Kennicutt law arises from variations in the evolutionary stage of star-forming molecular clouds, we compared molecular gas and recent star formation in an early-phase merger galaxy pair, Taffy I (UGC 12915/UGC 12914, VV 254) which went through a direct collision 20 Myr ago and whose star-forming regions are expected to have similar ages. Narrowband Pa{alpha} image is obtained using the ANIR near-infrared camera on the mini-TAO 1 m telescope. The image enables us to derive accurate star formation rates within the galaxy directly. The total star formation rate, 22.2 M{sub Sun} yr{sup -1}, was found to be much higher than previous estimates. Ages of individual star-forming blobs estimated from equivalent widths indicate that most star-forming regions are {approx}7 Myr old, except for a giant H II region at the bridge which is much younger. Comparison between star formation rates and molecular gas masses for the regions with the same age exhibits a surprisingly tight correlation, a slope of unity, and star formation efficiencies comparable to those of starburst galaxies. These results suggest that Taffy I has just evolved into a starburst system after the collision, and the star-forming sites are at a similar stage in their evolution from natal molecular clouds except for the bridge region. The tight Schmidt-Kennicutt law supports the scenario that dispersion in the star formation law is in large part due to differences in evolutionary stage of star-forming regions.

Komugi, S. [Joint ALMA Observatory, Alonso de Cordova 3107, Vitacura, Santiago 763-0355 (Chile); Tateuchi, K.; Motohara, K.; Kato, N.; Konishi, M.; Koshida, S.; Morokuma, T.; Takahashi, H.; Tanabe, T.; Yoshii, Y. [Institute of Astronomy, University of Tokyo, Osawa 2-21-1, Mitaka, Tokyo 181-0015 (Japan); Takagi, T. [Institute of Space and Astronautical Science, JAXA, 3-31-1 Yoshinodai, Sagamihara, Kanagawa 229-8510 (Japan); Iono, D.; Kaneko, H.; Ueda, J. [Nobeyama Radio Observatory, National Astronomical Observatory, 462-2 Nobeyama, Minamimaki, Minamisaku, Nagano 384-1305 (Japan); Saitoh, T. R., E-mail: skomugi@alma.cl [Interactive Research Center of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro 152-0033 (Japan)

2012-10-01

364

Predictions and observations of HF radio propagation in the northerly ionosphere: The effect of the solar flares and a weak CME in early January 2014.  

NASA Astrophysics Data System (ADS)

We have previously reported on a significant new multi-national project to provide improved predictions and forecasts of HF radio propagation for commercial aircraft operating on trans-polar routes. In these regions, there are limited or no VHF air-traffic control facilities and geostationary satellites are below the horizon. Therefore HF radio remains important in maintaining communications with the aircraft at all times. Space weather disturbances can have a range of effects on the ionosphere and hence HF radio propagation - particularly in the polar cap. While severe space weather effects can lead to a total loss of communications (i.e. radio blackout), less intense events can still cause significant disruption. In this paper we will present the effect of a series of M and X class solar flares and a relatively weak CME on HF radio performance from 6 to 13 January 2014. This is an interesting interval from the point of view of HF radio propagation because while the solar effects on the ionosphere are significant, except for an interval of approximately 12 hours duration, they are not so intense as to produce a complete radio blackout on all paths. Observations of the signal-to-noise ratio, direction of arrival, and time of flight of HF radio signals on six paths (one entirely within the polar cap, three trans-auroral, and two sub-auroral) will be presented together with riometer measurements of the ionospheric absorption. Global maps of D-region absorption (D-region absorption prediction, DRAP) inferred from satellite measurements of the solar wind parameters will be compared with the HF and riometer observations. In addition, a ray-tracing model using a realistic background ionosphere and including localised features found in the ionospheric polar cap (e.g. polar patches and arcs) will be used to model the expected and observed HF radio propagation characteristics.

Hallam, Jonathan; Stocker, Alan J.; Warrington, Mike; Siddle, Dave; Zaalov, Nikolay; Honary, Farideh; Rogers, Neil; Boteler, David; Danskin, Donald

2014-05-01

365

Serial-parallel decompositions of Mueller matrices.  

PubMed

The algebraic methods for serial and parallel decompositions of Mueller matrices are combined in order to obtain a general framework for a suitable analysis of polarimetric measurements based on equivalent systems constituted by simple components. A general procedure for the parallel decomposition of a Mueller matrix into a convex sum of pure elements is presented and applied to the two canonical forms of depolarizing Mueller matrices [Ossikovski, J. Opt. Soc. Am. A 27, 123 (2010).], leading to the serial-parallel decomposition of any Mueller matrix. The resultant model is consistent with the mathematical structure and the reciprocity properties of Mueller matrices. PMID:23456000

Gil, José J; San José, Ignacio; Ossikovski, Razvigor

2013-01-01

366

Stability of the Trotter-Suzuki decomposition  

NASA Astrophysics Data System (ADS)

The Trotter-Suzuki decomposition (TSD) is an important tool for the simulation and control of physical systems. We provide evidence for the stability of the TSD. We model the error in the decomposition and determine sufficiency conditions that guarantee the stability of this decomposition under this model. We relate these sufficiency conditions to precision limitations of computing and control in both classical and quantum cases. Furthermore we show that bounded-error TSD can be achieved by a suitable choice of machine precision.

Dhand, Ish; Sanders, Barry C.

2014-07-01

367

Early Literacy  

Microsoft Academic Search

\\u000a This chapter explores the connections and disconnections between children’s oral language\\u000a \\u000a and early literacy\\u000a \\u000a . It begins with studies of oral language\\u000a \\u000a as a predictor of early literacy\\u000a \\u000a and then moves on to exploring early literacy\\u000a \\u000a development in homes, early education and care, and the first years of school. Examples of pedagogies incorporating children’s\\u000a ‘funds of knowledge’ from homes and

Susan Hill

368

To what extent does the Health Professions Admission Test-Ireland predict performance in early undergraduate tests of communication and clinical skills? – An observational cohort study  

PubMed Central

Background Internationally, tests of general mental ability are used in the selection of medical students. Examples include the Medical College Admission Test, Undergraduate Medicine and Health Sciences Admission Test and the UK Clinical Aptitude Test. The most widely used measure of their efficacy is predictive validity. A new tool, the Health Professions Admission Test- Ireland (HPAT-Ireland), was introduced in 2009. Traditionally, selection to Irish undergraduate medical schools relied on academic achievement. Since 2009, Irish and EU applicants are selected on a combination of their secondary school academic record (measured predominately by the Leaving Certificate Examination) and HPAT-Ireland score. This is the first study to report on the predictive validity of the HPAT-Ireland for early undergraduate assessments of communication and clinical skills. Method Students enrolled at two Irish medical schools in 2009 were followed up for two years. Data collected were gender, HPAT-Ireland total and subsection scores; Leaving Certificate Examination plus HPAT-Ireland combined score, Year 1 Objective Structured Clinical Examination (OSCE) scores (Total score, communication and clinical subtest scores), Year 1 Multiple Choice Questions and Year 2 OSCE and subset scores. We report descriptive statistics, Pearson correlation coefficients and Multiple linear regression models. Results Data were available for 312 students. In Year 1 none of the selection criteria were significantly related to student OSCE performance. The Leaving Certificate Examination and Leaving Certificate plus HPAT-Ireland combined scores correlated with MCQ marks. In Year 2 a series of significant correlations emerged between the HPAT-Ireland and subsections thereof with OSCE Communication Z-scores; OSCE Clinical Z-scores; and Total OSCE Z-scores. However on multiple regression only the relationship between Total OSCE Score and the Total HPAT-Ireland score remained significant; albeit the predictive power was modest. Conclusion We found that none of our selection criteria strongly predict clinical and communication skills. The HPAT- Ireland appears to measures ability in domains different to those assessed by the Leaving Certificate Examination. While some significant associations did emerge in Year 2 between HPAT Ireland and total OSCE scores further evaluation is required to establish if this pattern continues during the senior years of the medical course. PMID:23663266

2013-01-01

369

Architecture-driven Problem Decomposition  

Microsoft Academic Search

Jackson's Problem Frames provide a means of analysing and decomposing problems. They emphasise the world out- side the computer helping the developer to focus on the problem domain instead of drifting into inventing solutions. The intention is to delay consideration of the solution space until a good understanding of the problem is gained. In contrast, early consideration of a solution

Lucia Rapanotti; Jon G. Hall; Michael Jackson; Bashar Nuseibeh

2004-01-01

370

Early lunar geology and geophysics  

E-print Network

Despite a number of human and robotic missions to the Moon, there are still important unanswered questions about its early evolution, and how it came to be the object we observe today. Here we use observational, experimental, ...

Garrick-Bethell, Ian, 1980-

2009-01-01

371

Mid-Cretaceous charred fossil flowers reveal direct observation of arthropod feeding strategies  

PubMed Central

Although plant–arthropod relationships underpin the dramatic rise in diversity and ecological dominance of flowering plants and their associated arthropods, direct observations of such interactions in the fossil record are rare, as these ephemeral moments are difficult to preserve. Three-dimensionally preserved charred remains of Chloranthistemon flowers from the Late Albian to Early Cenomanian of Germany preserve scales of mosquitoes and an oribatid mite with mouthparts inserted into the pollen sac. Mosquitoes, which today are frequent nectar feeders, and the mite were feeding on pollen at the time wildfire consumed the flowers. These findings document directly arthropod feeding strategies and their role in decomposition. PMID:21900310

Hartkopf-Fröder, Christoph; Rust, Jes; Wappler, Torsten; Friis, Else Marie; Viehofen, Agnes

2012-01-01

372

An observational study of bimatoprost 0.01% in patients on prior intraocular pressure-lowering therapy: the Canadian Lumigan® RC Early Analysis Review (CLEAR) trial  

PubMed Central

Purpose To evaluate the ocular hyperemia and intraocular pressure (IOP)-lowering efficacy of bimatoprost 0.01% in subjects with elevated IOP due to primary open-angle glaucoma (POAG) or ocular hypertension (OHT) in a real-world clinical setting. Subjects and methods This open-label, 12-week, observational study was conducted at 67 centers in Canada. Subjects with elevated IOP due to POAG or OHT instilled bimatoprost 0.01% as monotherapy once daily. Ocular hyperemia was graded by the investigator at baseline, week 6, and week 12 using a standardized photographic 5-point grading scale. Change in IOP from baseline was also evaluated at these time points. This analysis includes the subgroup of 268 subjects who had been previously treated with latanoprost 0.005%, bimatoprost 0.03%, travoprost 0.004%, and travoprost 0.004% with SofZia™ or nonselective beta-adrenergic receptor blockers prior to the study. Results After 12 weeks of treatment with 0.01% bimatoprost, ocular hyperemia was graded as none-to-mild hyperemia (grades 0, +0.5, or +1) for 94.1% of subjects and as moderate-to-severe hyperemia (grades +2 or +3) for 5.9%. No statistically significant shifts in ocular hyperemia ratings were observed at week 12 for any of the prior IOP-lowering therapies except bimatoprost 0.03%, in which 20.8% of subjects experienced an improvement. The mean percentage change from baseline IOP at week 12 following the switch to bimatoprost 0.01% monotherapy ranged from ?2.3%±17.3% to ?26.3%±12.4%. Furthermore, the decreased mean percentage change from baseline IOP was statistically significant across all prior IOP-lowering medications, except for bimatoprost 0.03% at the 6- and 12-week visits and travoprost 0.004% at the 6-week visit. Conclusion This observational study demonstrates that bimatoprost 0.01% was well tolerated among POAG and OHT subjects who switched from prior IOP-lowering medication. Furthermore, a switch in ocular hypertensive treatment to bimatoprost 0.01% was associated with an additional 10%–15% reduction in IOP. PMID:24920879

Crichton, Andrew C; Nixon, Donald R; Simonyi, Susan; Bhogal, Meetu; Sigouin, Christopher S; Discepola, Marino J; Hutnik, Cindy ML; Baptiste, Darryl C; Yan, David B

2014-01-01

373

Experimental Shock Decomposition of Siderite to Magnetite  

NASA Technical Reports Server (NTRS)

The debate about fossil life on Mars includes the origin of magnetites of specific sizes and habits in the siderite-rich portions of the carbonate spheres in ALH 84001 [1,2]. Specifically [2] were able to demonstrate that inorganic synthesis of these compositionally zoned spheres from aqueous solutions of variable ion-concentrations is possible. They further demonstrated the formation of magnetite from siderite upon heating at 550 C under a Mars-like CO2-rich atmosphere according to 3FeCO3 = Fe3O4 + 2CO2 + CO [3] and they postulated that the carbonates in ALH 84001 were heated to these temperatures by some shock event. The average shock pressure for ALH 84001, substantially based on the refractive index of diaplectic feldspar glasses [3,4,5] is some 35-40 GPa and associated temperatures are some 300-400 C [4]. However, some of the feldspar is melted [5], requiring local deviations from this average as high as 45-50 GPa. Indeed, [5] observes the carbonates in ALH 84001 to be melted locally, requiring pressures in excess of 60 GPa and temperatures > 600 C. Combining these shock studies with the above inorganic synthesis of zoned carbonates it seems possible to produce the ALH 84001 magnetites by the shock-induced decomposition of siderite.

Bell, M. S.; Golden, D. C.; Zolensky, M. E.

2005-01-01

374

The early mineralization of enamel  

Microsoft Academic Search

Summary The potassium pyroantimonate technique was used to study the cellular distribution of calcium during the early mineralization of enamel in rat molar tooth germs at the electron microscope level. Differing patterns of calcium distribution were observed in the ameloblast seemingly associated with the appearance of Tomes' process. In the early secretory ameloblast calcium pyroantimonate deposits were observed within the

D. A. Deporter

1977-01-01

375

Comparison of the Decomposition VOC Profile during Winter and Summer in a Moist, Mid-Latitude (Cfb) Climate  

PubMed Central

The investigation of volatile organic compounds (VOCs) associated with decomposition is an emerging field in forensic taphonomy due to their importance in locating human remains using biological detectors such as insects and canines. A consistent decomposition VOC profile has not yet been elucidated due to the intrinsic impact of the environment on the decomposition process in different climatic zones. The study of decomposition VOCs has typically occurred during the warmer months to enable chemical profiling of all decomposition stages. The present study investigated the decomposition VOC profile in air during both warmer and cooler months in a moist, mid-latitude (Cfb) climate as decomposition occurs year-round in this environment. Pig carcasses (Sus scrofa domesticus L.) were placed on a soil surface to decompose naturally and their VOC profile was monitored during the winter and summer months. Corresponding control sites were also monitored to determine the natural VOC profile of the surrounding soil and vegetation. VOC samples were collected onto sorbent tubes and analyzed using comprehensive two-dimensional gas chromatography – time-of-flight mass spectrometry (GC×GC-TOFMS). The summer months were characterized by higher temperatures and solar radiation, greater rainfall accumulation, and comparable humidity when compared to the winter months. The rate of decomposition was faster and the number and abundance of VOCs was proportionally higher in summer. However, a similar trend was observed in winter and summer demonstrating a rapid increase in VOC abundance during active decay with a second increase in abundance occurring later in the decomposition process. Sulfur-containing compounds, alcohols and ketones represented the most abundant classes of compounds in both seasons, although almost all 10 compound classes identified contributed to discriminating the stages of decomposition throughout both seasons. The advantages of GC×GC-TOFMS were demonstrated for detecting and identifying trace levels of VOCs, particularly ethers, which are rarely reported as decomposition VOCs. PMID:25412504

Forbes, Shari L.; Perrault, Katelynn A.; Stefanuto, Pierre-Hugues; Nizio, Katie D.; Focant, Jean-François

2014-01-01

376

Landscape-level variation in temperature sensitivity of soil organic carbon decomposition  

Microsoft Academic Search

We examined landscape-level variation in temperature sensitivity of labile SOC across 71 sites at a central North American grassland. The observed range in activation energy of decomposition (Ea), an index of temperature sensitivity, was as great at the landscape scale as has been observed at the continental scale. Ea was lower for soils with more labile C, consistent with the

Joseph Craine; Rebecca Spurr; Kendra McLauchlan; Noah Fierer

2010-01-01

377

Ionic Crystal Decomposition with Light  

NASA Astrophysics Data System (ADS)

We report on RbI crystal decomposition due to electronic excitations in a vicinity of the top of the crystal band gap by UV photon irradiation. Dynamic Force Microscopy (DFM) studies reveal that randomly spread rectangular pits of monolayer depth in the topmost layer of the crystal are formed during irradiation. Growth and coalescence of the pits lead to almost `layer-by-layer' desorption mode. Similarly to electron stimulated desorption, periodic changes of surface topography were found to have a profound effect on the desorption process. Since excited F-centre recombination with alkali atom emission was possible exclusively at low-coordinated sites the desorption yields were found to go hand in hand with the number of low-coordinated sites on the surface. Furthermore, simultaneous irradiation of the crystal by UV photons and visible light within the F-centre absorption band increases average F-centre mobility which has a profound effect on process efficiency. Such processes could be applied in controlled surface nanostructuring.

Szymonski, M.; Struski, P.; Siegel, A.; Kolodziej, J. J.; Such, B.; Piatkowski, P.; Czuba, P.; Krok, F.

2002-08-01

378

Thermal Decomposition Kinetics of HMX  

SciTech Connect

Nucleation-growth kinetic expressions are derived for thermal decomposition of HMX from a variety of types of data, including mass loss for isothermal and constant rate heating in an open pan, and heat flow for isothermal and constant rate heating in open and closed pans. Conditions are identified in which thermal runaway is small to nonexistent, which typically means temperatures less than 255 C and heating rates less than 1 C/min. Activation energies are typically in the 140 to 165 kJ/mol regime for open pan experiments and about 150-165 kJ/mol for sealed-pan experiments. The reaction clearly displays more than one process, and most likely three processes, which are most clearly evident in open pan experiments. The reaction is accelerated for closed pan experiments, and one global reaction fits the data fairly well. Our A-E values lie in the middle of the values given in a compensation-law plot by Brill et al. (1994). Comparison with additional open and closed low temperature pyrolysis experiments support an activation energy of 165 kJ/mol at 10% conversion.

Burnham, A K; Weese, R K

2005-03-17

379

Unimolecular thermal decomposition of dimethoxybenzenes  

NASA Astrophysics Data System (ADS)

The unimolecular thermal decomposition mechanisms of o-, m-, and p-dimethoxybenzene (CH3O-C6H4-OCH3) have been studied using a high temperature, microtubular (?tubular) SiC reactor with a residence time of 100 ?s. Product detection was carried out using single photon ionization (SPI, 10.487 eV) and resonance enhanced multiphoton ionization (REMPI) time-of-flight mass spectrometry and matrix infrared absorption spectroscopy from 400 K to 1600 K. The initial pyrolytic step for each isomer is methoxy bond homolysis to eliminate methyl radical. Subsequent thermolysis is unique for each isomer. In the case of o-CH3O-C6H4-OCH3, intramolecular H-transfer dominates leading to the formation of o-hydroxybenzaldehyde (o-HO-C6H4-CHO) and phenol (C6H5OH). Para-CH3O-C6H4-OCH3 immediately breaks the second methoxy bond to form p-benzoquinone, which decomposes further to cyclopentadienone (C5H4=O). Finally, the m-CH3O-C6H4-OCH3 isomer will predominantly follow a ring-reduction/CO-elimination mechanism to form C5H4=O. Electronic structure calculations and transition state theory are used to confirm mechanisms and comment on kinetics. Implications for lignin pyrolysis are discussed.

Robichaud, David J.; Scheer, Adam M.; Mukarakate, Calvin; Ormond, Thomas K.; Buckingham, Grant T.; Ellison, G. Barney; Nimlos, Mark R.

2014-06-01

380

Nonnegative Decomposition of Multivariate Information  

E-print Network

Of the various attempts to generalize information theory to multiple variables, the most widely utilized, interaction information, suffers from the problem that it is sometimes negative. Here we reconsider from first principles the general structure of the information that a set of sources provides about a given variable. We begin with a new definition of redundancy as the minimum information that any source provides about each possible outcome of the variable, averaged over all possible outcomes. We then show how this measure of redundancy induces a lattice over sets of sources that clarifies the general structure of multivariate information. Finally, we use this redundancy lattice to propose a definition of partial information atoms that exhaustively decompose the Shannon information in a multivariate system in terms of the redundancy between synergies of subsets of the sources. Unlike interaction information, the atoms of our partial information decomposition are never negative and always support a clear interpretation as informational quantities. Our analysis also demonstrates how the negativity of interaction information can be explained by its confounding of redundancy and synergy.

Paul L. Williams; Randall D. Beer

2010-04-14

381

Unimolecular decomposition of methyltrichlorosilane: RRKM calculations  

SciTech Connect

Based on reaction thermochemistry and estimates of Arrhenius A-factors, it is expected that Si-C bond cleavage, C-H bond cleavage, and HCl elimination will be the primary channels for the unimolecular decomposition of methyltrichlorosilane. Using RRKM theory, we calculated rate constants for these three reactions. The calculations support the conclusion that these three reactions are the major decomposition pathways. Rate constants for each reaction were calculated in the high-pressure limit (800--1500 K) and in the falloff regime (1300--1500 K) for bath gases of both helium and hydrogen. These calculations thus provide branching fractions as well as decomposition rates. We also calculated bimolecular rate constants for the overall decomposition in the low-pressure limit. Interesting and surprising kinetic behavior of this system and the individual reactions is discussed. The reactivity of this chlorinated organosilane is compared to that of other organosilanes.

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

1993-06-01

382

Phase Field Method: Spinodal Decomposition Computer Laboratory  

NSDL National Science Digital Library

In this lab, spinodal decomposition is numerically implemented in FiPy. A simple example python script (spinodal.py) summarizes the concepts. This lab is intended to complement the "Phase Field Method: An Introduction" lecture

Garcã­a, R. E.

2008-08-25

383

Finite element decomposition of the human neocortex  

E-print Network

boundary-conforming local coordinate systems for the systematic study and visualization of cortical neuron populations. The decomposition method is implemented with a newly developed set of object-oriented software tools....

Chow, Seeling

2012-06-07

384

Collisional Decomposition of SF_6^- by N_2  

NASA Astrophysics Data System (ADS)

The widely used gaseous dielectric SF6 is a potentially potent greenhouse gas. It has been suggested that N_2/SF6 mixtures might, in some applications, serve as a replacement for pure SF_6. In order to improve the understanding of dielectric properties of N_2/SF6 mixtures, total cross sections for electron detachment and collision induced dissociation (CID) have been measured for SF_6^- + N2 for relative collision energies 2 < E < 80 eV. Within this energy range, cross sections for electron detachment are small, and CID is the dominant destruction mechanism for SF_6^-. These experimental results are remarkably similar to those obtained earlier for inert gas targets, suggesting that the processes are largely independent of target's structure. Hence, collisional decomposition has been modeled with a two-step mechanism in which collisional excitation of SF_6^- to SF_6^-* is followed by unimolecular decomposition of SF_6^-*. Unimolecular decomposition rates are based upon recent thermochemical data and a statistical theory first proposed by Klots^1. The model results are in qualitative agreement with the experimental observations. ^1 C. E. Klots, Chem. Phys. Lett. 38, 61 (1976) This work was supported in part by the U.S. DOE, Basic Energy Sciences, Div of Chem. Sciences

Dyakov, Ilya; Peko, Brian; Champion, Roy

1999-10-01

385

AN ALTERNATIVE ALGORITHM FOR REFINEMENT OF ULV DECOMPOSITIONS  

E-print Network

-revealing two-sided orthogonal decompositions used to approximate the singular value decomposition (SVD #12; Complete Orthogonal Decompositions (CODs) can compute a approximation to the dichotomy in (1 m#2;n is left orthogonal, V 2 R n#2;n is orthogonal. The #12;rst such decompositions were proposed

Barlow, Jesse

386

Critical analysis of nitramine decomposition data: Activation energies and frequency factors for HMX and RDX decomposition  

NASA Technical Reports Server (NTRS)

A summary of a literature review on thermal decomposition of HMX and RDX is presented. The decomposition apparently fits first order kinetics. Recommended values for Arrhenius parameters for HMX and RDX decomposition in the gaseous and liquid phases and for decomposition of RDX in solution in TNT are given. The apparent importance of autocatalysis is pointed out, as are some possible complications that may be encountered in interpreting extending or extrapolating kinetic data for these compounds from measurements carried out below their melting points to the higher temperatures and pressure characteristic of combustion.

Schroeder, M. A.

1980-01-01

387

Domain decomposition for the SPN solver MINOS  

SciTech Connect

In this article we present a domain decomposition method for the mixed SPN equations, discretized with Raviart-Thomas-Nedelec finite elements. This domain decomposition is based on the iterative Schwarz algorithm with Robin interface conditions to handle communications. After having described this method, we give details on how to optimize the convergence. Finally, we give some numerical results computed in a realistic 3D domain. The computations are done with the MINOS solver of the APOLLO3 (R) code. (authors)

Jamelot, Erell; Baudron, Anne-Marie; Lautard, Jean-Jacques [CEA Saclay, DEN DANS DM2S SERMA LLPR, Commissariat Energie Atom et Energies Alternat, F-91191 Gif Sur Yvette, (France)

2012-07-01

388

Mueller matrix decomposition for biological tissue analysis  

NASA Astrophysics Data System (ADS)

This study deals with the polarimetric characterization of biological tissues based on the Stokes-Mueller formalism. The optimal experimental conditions to study irradiated pig skin samples are analyzed. Two Mueller matrix decomposition techniques, the one developed by Lu and Chipman and the other by Ossikovski, are used. These decompositions allow identification of useful factors such as retardance, diattenuation and depolarization for differentiating between various levels of irradiation and for better interpreting the behavior of the skin with respect to irradiation.

Martin, L.; Le Brun, G.; Le Jeune, B.

2013-04-01

389

Thermal decomposition of mechanically activated tetrahedrite  

Microsoft Academic Search

A comparative study of the thermal non-oxidative decomposition of tetrahedrite Cu12Sb4S13 ground in a planetary mill has shown that the mechanical activation does not change the mechanism of this decomposition but has positive influence on its rate. The formation of agglomerates from finely ground particles of tetrahedrite restricts the extent of this influence. Bornite Cu5FeS4 and digenite Cu1.765S were identified

P. Baláž; J. Brian?in; L' Tur?ániová

1995-01-01

390

High temperature decomposition of hydrogen peroxide  

NASA Technical Reports Server (NTRS)

Nitric oxide (NO) is oxidized into nitrogen dioxide (NO2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydroperoxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

Parrish, Clyde F. (Inventor)

2005-01-01

391

High Temperature Decomposition of Hydrogen Peroxide  

NASA Technical Reports Server (NTRS)

Nitric oxide (NO) is oxidized into nitrogen dioxide (NO2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydropemxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

Parrish, Clyde F. (Inventor)

2004-01-01

392

Polynomial Matrix Decompositions: Algorithms and Applications  

E-print Network

and with different delays Polynomial mixing matrix required, where each element is an FIR filter More realistic multichannel all-pass filter): Az=Az Hz H z= Hz H z=I A z = A ¿ T 1/z det[ Az]=constant #12;7 http://www the decompositions Motivation: the QR decomposition in narrowband signal processing a11 a21 a22 a12 x1 x2 y1 y2 [y1 y

Davies, Christopher

393

Decomposition of fluorophosphoryl diazide: a joint experimental and theoretical study.  

PubMed

The photolytic and thermal decomposition of fluorophosphoryl diazide, FP(O)(N3)2, was studied using matrix isolation spectroscopy. Upon ArF laser photolysis (? = 193 nm), FPO and a new geminal azido nitrene FP(O)(N3)N were identified using matrix IR spectroscopy. The nitrene shows a triplet ground state with the zero-field parameters |D/hc| = 1.566 cm(-1) and |E/hc| = 0.005 cm(-1). Further decomposition of the nitrene into FPO was observed under an irradiation of ? > 335 nm. In contrast, no nitrene but only FPO was identified after flash vacuum pyrolysis of the diazide. To reveal the decomposition mechanism, quantum chemical calculations on the potential energy surface (PES) of the diazide using DFT methods were performed. On the singlet PES four conformers of the nitrene were predicted. The two conformers (syn and anti) showing intramolecular NnitreneN?,azide interactions are much lower in energy (ca. 40 kJ mol(-1), B3LYP/6-311+G(3df)) than the other two exhibiting NnitreneO interactions. syn/anti refers to the relative orientation of the P[double bond, length as m-dash]O bond and the N3 group. The interconversion of these species and the decomposition into FPO via a novel three-membered ring diazo intermediate cyclo-FP(O)N2 were computationally explored. The calculated low dissociation barrier of 45 kJ mol(-1) (B3LYP/6-311+G(3df)) of this cyclic intermediate rationalizes why it could not be detected in our experiments. PMID:25656843

Li, Dingqing; Li, Hongmin; Zhu, Bifeng; Zeng, Xiaoqing; Willner, Helge; Beckers, Helmut; Neuhaus, Patrik; Grote, Dirk; Sander, Wolfram

2015-02-18

394

Tensor decomposition and vibrational coupled cluster theory.  

PubMed

The use of tensor decomposition in the calculation of anharmonic vibrational wave functions is discussed. The correlation amplitudes of vibrational coupled cluster (VCC) and vibrational configuration interaction (VCI) theories are considered as tensors and decomposed. A pilot code is implemented allowing a numerical study of the performance of the canonical decomposition/parallel factors (CP) for three and higher mode couplings in computations on water, formaldehyde, and 1,2,5-thiadiazole. The results show that there is a significant perspective in applying tensor decomposition in the context of anharmonic vibrational wave functions, with the CP tensor decomposition providing compression of data and a computational convenient representation. The calculations also illustrate how the multiplicative separability of the VCC ansatz with respect to noninteracting degrees of freedom goes well together with a tensor decomposition approach. Tensor decomposition opens for adjusting the computational effort spent on a particular mode-coupling according to the significance of that particular coupling, which is guaranteed to decrease to zero in the case of VCC in the limit of noninteracting subsystems. PMID:23662994

Godtliebsen, Ian H; Thomsen, Bo; Christiansen, Ove

2013-08-15

395

Decomposition of methanol on oxygen-modified Fe(100) surfaces. II. Preadsorbed oxygen as poison, selectivity modifier and promoter  

NASA Astrophysics Data System (ADS)

Decomposition of methanol (CH 3OH) on the Fe(100) surface modified by low temperature adsorption of oxygen has been studied, using high resolution electron energy loss spectroscopy (HREELS) and temperature programmed reaction spectroscopy (TPRS). Fe(100) surfaces studied were modified by adsorption of O 2 at 113 K, and methanol decomposition as a function of oxygen coverage was monitored. The effect of pre-heating the oxygen overlayers on the methanol decomposition was also examined. Decomposition of methanol on these O-modified surfaces passes through a methoxy (-OCH 3) intermediate. The thermal stability of methoxy increases in the presence of pre-adsorbed oxygen. At low coverage, atomic oxygen occupies four-fold hollow sites. In this case, the effect of oxygen on the methanol decomposition is similar to that observed previously on the annealed O-modified surfaces. At higher oxygen coverage, a more weakly bound non-hollow site oxygen also exists on the surface, which reacts with hydroxyl (-OH) hydrogen of the CH 3OH, promoting the formation of methoxy. At high oxygen coverage (close to saturation coverage at 113 K), decomposition of methanol results in the formation of formaldehyde (H 2CO), without production of carbon monoxide (CO). This is very different from the decomposition of methanol on the clean Fe(100) surface, where decomposition leads to the formation of CO without H 2CO. The effect of oxygen modification is discussed in terms of changing relative probabilities of competing reaction pathways.

Lu, Jiong-Ping; Albert, Mark; Bernasek, Steven L.; Dwyer, Daniel J.

1990-12-01

396

Sensitivity of soil organic matter decomposition to simultaneous changes in temperature and moisture  

NASA Astrophysics Data System (ADS)

Soil organic matter decomposition depends on multiple factors that are being altered simultaneously as a result of global environmental change. For this reason it is important to study the overall sensitivity of soil organic matter decomposition with respect to multiple and interacting drivers. Here we present an analysis of the potential response of decomposition rates to simultaneous changes in temperature and moisture. To address this problem, we first present a theoretical framework to study the sensitivity of soil organic matter decomposition when multiple driving factors change simultaneously. We then apply this framework to models and data at different levels of abstraction: 1) to a mechanistic model that addresses the limitation of enzyme activity by simultaneous effects of temperature and soil water content, the latter controlling substrate supply and oxygen concentration for microbial activity; 2) to different mathematical functions used to represent temperature and moisture effects on decomposition in biogeochemical models. To contrast model predictions at these two levels of organization, we compiled different datasets of observed responses in field and laboratory studies. Then we applied our conceptual framework to: 3) observations of soil respiration at the ecosystem level; 4) laboratory experiments looking at the response of heterotrophic respiration to independent changes in moisture and temperature; and 5) ecosystem-level experiments manipulating soil temperature and water content simultaneously. The combined theoretical and empirical evidence reviewed suggests: first, large uncertainties still remain regarding the combined controls of temperature and moisture on decomposition rates, particularly at high temperatures and the extremes of the soil moisture range; second, the highest sensitivities of decomposition rates are likely in systems where temperature and moisture are high such as tropical peatlands, and at temperatures near the freezing point of water such as in soils under freeze-thaw cycles. These regions also exhibit the largest differences in projected changes in decomposition rates among different models. Third, the lowest sensitivity of decomposition rates to changes in temperature and moisture is expected in soils with temperatures well below the freezing point. Uncertainty in models can be reduced if some of the functions representing the effects of temperature and moisture on decomposition can be discredited based on empirical observations or experiments.

Sierra, Carlos; Trumbore, Susan; Davidson, Eric; Vicca, Sara; Janssens, Ivan

2014-05-01

397

Azo dye Acid Red 27 decomposition kinetics during ozone oxidation and adsorption processes.  

PubMed

To elucidate the effects of ozone dosage, catalysts, and temperature on azo dye decomposition rate in treatment processes, the decomposition kinetics of Acid Red 27 by ozone was investigated. Acid Red 27 decomposition rate followed the first-order reaction with complete dye discoloration in 20 min of ozone reaction. The dye decay rate increases as ozone dosage increases. Using Mn, Zn and Ni as transition metal catalysts during the ozone oxidation process, Mn displayed the greatest catalytic effect with significant increase in the rate of decomposition. The rate of decomposition decreases with increase in temperature and beyond 40 degrees C, increase in decomposition rate was followed by a corresponding increase in temperature. The FT-IR spectra in the range of 1,000-1,800 cm(-1) revealed specific band variations after the ozone oxidation process, portraying structural changes traceable to cleavage of bonds in the benzene ring, the sulphite salt group, and the C-N located beside the -N = N- bond. From the (1)H-NMR spectra, the breaking down of the benzene ring showed the disappearance of the 10 H peaks at 7-8 ppm, which later emerged with a new peak at 6.16 ppm. In a parallel batch test of azo dye Acid Red 27 adsorption onto activated carbon, a low adsorption capacity was observed in the adsorption test carried out after three minutes of ozone injection while the adsorption process without ozone injection yielded a high adsorption capacity. PMID:19337926

Beak, Mi H; Ijagbemi, Christianah O; Kim, Dong S

2009-05-01

398

Decomposition is always temperature dependent, except when its not  

NASA Astrophysics Data System (ADS)

Understanding of the temperature dependence of decomposition of soil organic matter has been complicated by the two following facts: (1) all enzymatic activity, including biologically mediated breakdown of organic matter in soils, is temperature dependent; and (2) much of the organic matter in soils is effectively isolated from enzymatic activity, either in space or time, through a wide variety of environmental constraints, including physical and chemical protection, spatial heterogeneity, lack of oxygen, or sub-zero temperatures. Because of the second fact, the first has been questioned in papers that report lack of observed temperature sensitivity of decomposition of soil organic matter. In my 2006 review paper with Ivan Janssens, we attempted to clarify these facts and their interactions and why temperature dependence is sometimes observed and sometimes not. However, it appears that our discussion of how Arrhenius kinetics affects enzymatic activity has become the paper's main recognized legacy, and it has been cited in support of the "carbon-quality-temperature" hypothesis. Here I will update and clarify aspects of that review as follows: (1) a Dual Arrhenius Michaelis-Menten (DAMM) model that merges these kinetic models with substrate diffusion processes can parsimoniously and mechanistically explain fast responses of carbon metabolism in soils as temperature and water content vary over time scales of minutes to months; and (2) variations in activation energies of enzymatic reactions have little or no effect on C metabolism when substrate is not available to enzymes, and this second point applies to both short and long-term turnover of soil organic matter. Because of this latter point, mean residence times and decomposition constants often do not correlate well with the chemical structure ("carbon quality") of soil organic matter, as is predicted by Arrhenius kinetics alone. While it is true that biological decomposition reactions, when they occur, are always temperature dependent, and that Arrhenius kinetics, including varying activation energies as functions of substrate complexity, are useful for describing enzymatic reactions when substrate is not limiting, these facts are insufficient to explain residence times of carbon in soil unless they are integrated with understanding of the factors that effectively isolate substrates from enzymes. The most important feedback to climate change involving decomposition may not be the consequence of the temperature dependence of enzymatic processes per se, but rather due the exposure to enzymes of substrates that were previously effectively isolated in permafrost and wetlands.

Davidson, E. A.

2011-12-01

399

Spectral decomposition aids AVO analysis in reservoir characterization: A case study of Blackfoot field, Alberta, Canada  

NASA Astrophysics Data System (ADS)

Blackfoot field, Alberta, Canada, has produced oil and gas from a Glauconitic compound incised valley-system. In this area channels can be filled with sands and/or shales. Differentiation of prospective channel sands and non-productive shales was always problematic due to the similarity in P-wave impedance of these two lithotypes. We study the spectral decomposition response to the hydrocarbons presence in the Glauconitic channel of Early Cretaceous age. From previous AVO analysis and modeling, a strong Class III AVO anomaly has been observed at the top of the porous sandstone in the upper valley, whereas shale had a very different AVO response. Furthermore, AVO inversion revealed additional information about lithology and fluid content in the channel. Our workflow starts from selecting a continuous horizon that was close and conforms to the channel interval; we then run spectral analyses for the channel area. Short Window Fourier Transform workflow could successfully image the channel's stratigraphic features and confirm results obtained from AVO analysis and inversion run on the data before being stacked. Additionally, the producing oil wells in the sand-fill channel were found to be correlating with high spectrum amplitude; while the dry wells in the shale-plugged channel fell in low amplitude anomaly.

Jung Yoon, Wang; Farfour, Mohammed

2012-09-01

400

Deep coastal marine taphonomy: investigation into carcass decomposition in the Saanich Inlet, British Columbia using a baited camera.  

PubMed

Decomposition and faunal colonization of a carcass in the terrestrial environment has been well studied, but knowledge of decomposition in the marine environment is based almost entirely on anecdotal reports. Three pig carcasses were deployed in Saanich Inlet, BC, over 3 years utilizing Ocean Network Canada's VENUS observatory. Each carcass was deployed in late summer/early fall at 99 m under a remotely controlled camera and observed several times a day. Dissolved oxygen, temperature, salinity, density and pressure were continuously measured. Carcass 1 was immediately colonized by Munida quadrispina, Pandalus platyceros and Metacarcinus magister, rapidly scavenged then dragged from view by Day 22. Artifacts specific to each of the crustaceans' feeding patterns were observed. Carcass 2 was scavenged in a similar fashion. Exposed tissue became covered by Orchomenella obtusa (Family Lysianassidae) which removed all the internal tissues rapidly. Carcass 3 attracted only a few M. quadrispina, remaining intact, developing a thick filamentous sulphur bacterial mat, until Day 92, when it was skeletonized by crustacea. The major difference between the deployments was dissolved oxygen levels. The first two carcasses were placed when oxygen levels were tolerable, becoming more anoxic. This allowed larger crustacea to feed. However, Carcass 3 was deployed when the water was already extremely anoxic, which prevented larger crustacea from accessing the carcass. The smaller M. quadrispina were unable to break the skin alone. The larger crustacea returned when the Inlet was re-oxygenated in spring. Oxygen levels, therefore, drive the biota in this area, although most crustacea endured stressful levels of oxygen to access the carcasses for much of the time. These data will be valuable in forensic investigations involving submerged bodies, indicating types of water conditions to which the body has been exposed, identifying post-mortem artifacts and providing realistic expectations for recovery divers and families of the deceased. PMID:25329759

Anderson, Gail S; Bell, Lynne S

2014-01-01

401

Decomposition of forest products buried in landfills  

SciTech Connect

Highlights: • This study tracked chemical changes of wood and paper in landfills. • A decomposition index was developed to quantify carbohydrate biodegradation. • Newsprint biodegradation as measured here is greater than previous reports. • The field results correlate well with previous laboratory measurements. - Abstract: The objective of this study was to investigate the decomposition of selected wood and paper products in landfills. The decomposition of these products under anaerobic landfill conditions results in the generation of biogenic carbon dioxide and methane, while the un-decomposed portion represents a biogenic carbon sink. Information on the decomposition of these municipal waste components is used to estimate national methane emissions inventories, for attribution of carbon storage credits, and to assess the life-cycle greenhouse gas impacts of wood and paper products. Hardwood (HW), softwood (SW), plywood (PW), oriented strand board (OSB), particleboard (PB), medium-density fiberboard (MDF), newsprint (NP), corrugated container (CC) and copy paper (CP) were buried in landfills operated with leachate recirculation, and were excavated after approximately 1.5 and 2.5 yr. Samples were analyzed for cellulose (C), hemicellulose (H), lignin (L), volatile solids (VS), and organic carbon (OC). A holocellulose decomposition index (HOD) and carbon storage factor (CSF) were calculated to evaluate the extent of solids decomposition and carbon storage. Samples of OSB made from HW exhibited cellulose plus hemicellulose (C + H) loss of up to 38%, while loss for the other wood types was 0–10% in most samples. The C + H loss was up to 81%, 95% and 96% for NP, CP and CC, respectively. The CSFs for wood and paper samples ranged from 0.34 to 0.47 and 0.02 to 0.27 g OC g{sup ?1} dry material, respectively. These results, in general, correlated well with an earlier laboratory-scale study, though NP and CC decomposition measured in this study were higher than previously reported.

Wang, Xiaoming, E-mail: xwang25@ncsu.edu [Department of Civil, Construction, and Environmental Engineering, Campus Box 7908, North Carolina State University, Raleigh, NC 27695-7908 (United States); Padgett, Jennifer M. [Department of Civil, Construction, and Environmental Engineering, Campus Box 7908, North Carolina State University, Raleigh, NC 27695-7908 (United States); Powell, John S. [Department of Chemical and Biomolecular Engineering, Campus Box 7905, North Carolina State University, Raleigh, NC 27695-7905 (United States); Barlaz, Morton A. [Department of Civil, Construction, and Environmental Engineering, Campus Box 7908, North Carolina State University, Raleigh, NC 27695-7908 (United States)

2013-11-15

402

DARBY et al.: BACKING OFF: HIERARCHICAL DECOMPOSITION OF ACTIVITY 1 Backing Off: Hierarchical Decomposition of  

E-print Network

DARBY et al.: BACKING OFF: HIERARCHICAL DECOMPOSITION OF ACTIVITY 1 Backing Off: Hierarchical Decomposition of Activity for 3D Novel Pose Recovery John Darby1 j.darby@mmu.ac.uk Baihua Li1 b University of Toronto 3 School of Computer Science University of Manchester Abstract For model-based 3D human

Li, Baihua

403

Spinodal Decomposition of Binary Mixtures in Uniform Shear Flow  

NASA Astrophysics Data System (ADS)

The spinodal decomposition of binary mixtures in uniform shear flow is studied in the context of the time-dependent Ginzburg-Landau equation, approximated at one-loop order. We show that the structure factor obeys a generalized dynamical scaling with different growth exponents ?x = 5/4 and ?y = 1/4 in the flow and in the shear directions, respectively. The excess viscosity ?? after reaching a maximum relaxes to zero as ?-2t-3/2, ? being the shear rate. ?? and other observables exhibit log-time periodic oscillations which can be interpreted as due to a growth mechanism where stretching and breakup of domains cyclically occur.

Corberi, F.; Gonnella, G.; Lamura, A.

1998-11-01

404

Oxidative decomposition of formaldehyde catalyzed by a bituminous coal  

SciTech Connect

It has been observed that molecular hydrogen is formed during long-term storage of bituminous coals via oxidative decomposition of formaldehyde by coal surface peroxides. This study has investigated the effects of coal quantity, temperature, and water content on the molecular hydrogen formation with a typical American coal (Pittsburgh No. 6). The results indicate that the coal's surface serves as a catalyst in the formation processes of molecular hydrogen. Furthermore, the results also indicate that low temperature emission of molecular hydrogen may possibly be the cause of unexplained explosions in confined spaces containing bituminous coals, for example, underground mines or ship holds. 20 refs., 4 figs., 6 tabs.

Haim Cohen; Uri Green [Ariel University Center in Samaria, Beer Sheva (Israel). Biological Chemistry Department

2009-05-15

405

Decomposition of intermetallics during high-energy ball-milling  

Microsoft Academic Search

The decomposition behavior of FeSn, CoSn and CoIn2 intermetallics under high-energy ball-milling has been investigated using X-ray diffraction, calorimetric and magnetization measurements. Upon milling a large amount of the FeSn intermetallic decomposes into Fe5Sn3 and FeSn2, where the average grain size of the product phases stays nearly constant with milling-time. Similar observations are made for the CoSn intermetallic, which decomposes

Y. S. Kwon; P. P. Choi; J. S. Kim; D. H. Kwon; K. B. Gerasimov

2007-01-01

406

Catalytic decomposition of phosphorus compounds to produce phosphorus atoms  

NASA Astrophysics Data System (ADS)

Vacuum-ultraviolet laser-induced fluorescence identified atomic phosphorus in the gas phase when phosphine, triethylphosphine, or molecular phosphorus sublimated from solid red phosphorus was decomposed on heated metal wire surfaces. Atomic phosphorus was found to be one of the major products in all systems, and its density increased monotonically with wire temperature but showed saturation at high temperatures. A wire material dependence of density was observed for molecular phosphorus, suggesting that the decomposition of the compound is catalytic. Electron probe microanalyzer (EPMA) measurement showed that the wires are not phosphorized when heated in the presence of phosphine or molecular phosphorus.

Umemoto, Hironobu; Kanemitsu, Taijiro; Kuroda, Yuki

2014-01-01

407

Microwave Decomposition of Solid Crystalline Ammonium Paratungstate and Ammonium Metatungstate  

NASA Astrophysics Data System (ADS)

The potential for microwave decomposition of solid crystalline ammonium paratungstate (APT) and ammonium metatungstate (AMT) was investigated. It was observed that APT and AMT interact with 2.45-GHz microwave radiation. Samples of ammonium paratungstate (20-50 g) were successfully converted into WO 3- x (0 ? x ? 0.2). A wide variety of morphological parameters were found. The interaction of AMT with the 2.45-GHz microwave radiation resulted in the partial loss of crystalline water and the partial dissolution of the sample in the released water.

Pfeifer, J.; Badaljan, E. G.; Tekula-Buxbaum, P.; Vadasdi, K.

1993-08-01

408

Early Beginnings EARLY LITERACY KNOWLEDGE AND INSTRUCTION  

E-print Network

this booklet to: learn about early literacy development, review the early predictors of later successEarly Beginnings EARLY LITERACY KNOWLEDGE AND INSTRUCTION A guide for early childhood administrators and professional development providers #12;2 #12;Early Beginnings EARLY LITERACY KNOWLEDGE

Rau, Don C.

409

Global decomposition experiment shows soil animal impacts on decomposition are climate-dependent  

PubMed Central

Climate and litter quality are primary drivers of terrestrial decomposition and, based on evidence from multisite experiments at regional and global scales, are universally factored into global decomposition models. In contrast, soil animals are considered key regulators of decomposition at local scales but their role at larger scales is unresolved. Soil animals are consequently excluded from global models of organic mineralization processes. Incomplete assessment of the roles of soil animals stems from the difficulties of manipulating invertebrate animals experimentally across large geographic gradients. This is compounded by deficient or inconsistent taxonomy. We report a global decomposition experiment to assess the importance of soil animals in C mineralization, in which a common grass litter substrate was exposed to natural decomposition in either control or reduced animal treatments across 30 sites distributed from 43°S to 68°N on six continents. Animals in the mesofaunal size range were recovered from the litter by Tullgren extraction and identified to common specifications, mostly at the ordinal level. The design of the trials enabled faunal contribution to be evaluated against abiotic parameters between sites. Soil animals increase decomposition rates in temperate and wet tropical climates, but have neutral effects where temperature or moisture constrain biological activity. Our findings highlight that faunal influences on decomposition are dependent on prevailing climatic conditions. We conclude that (1) inclusion of soil animals will improve the predictive capabilities of region- or biome-scale decomposition models, (2) soil animal influences on decomposition are important at the regional scale when attempting to predict global change scenarios, and (3) the statistical relationship between decomposition rates and climate, at the global scale, is robust against changes in soil faunal abundance and diversity.

WALL, DIANA H; BRADFORD, MARK A; ST JOHN, MARK G; TROFYMOW, JOHN A; BEHAN-PELLETIER, VALERIE; BIGNELL, DAVID E; DANGERFIELD, J MARK; PARTON, WILLIAM J; RUSEK, JOSEF; VOIGT, WINFRIED; WOLTERS, VOLKMAR; GARDEL, HOLLEY ZADEH; AYUKE, FRED O; BASHFORD, RICHARD; BELJAKOVA, OLGA I; BOHLEN, PATRICK J; BRAUMAN, ALAIN; FLEMMING, STEPHEN; HENSCHEL, JOH R; JOHNSON, DAN L; JONES, T HEFIN; KOVAROVA, MARCELA; KRANABETTER, J MARTY; KUTNY, LES; LIN, KUO-CHUAN; MARYATI, MOHAMED; MASSE, DOMINIQUE; POKARZHEVSKII, ANDREI; RAHMAN, HOMATHEVI; SABARÁ, MILLOR G; SALAMON, JOERG-ALFRED; SWIFT, MICHAEL J; VARELA, AMANDA; VASCONCELOS, HERALDO L; WHITE, DON; ZOU, XIAOMING

2008-01-01

410

Changes in the adsorption of bisphenol A, 17 ?-ethinyl estradiol, and phenanthrene on marine sediment in Hong Kong in relation to the simulated sediment organic matter decomposition.  

PubMed

Marine sediment with an input of particulate organic matter was incubated to simulate the early aging process. On the sediment after various incubation periods, adsorption and desorption tests were conducted for three selected organic micropollutants: bisphenol A (BPA), 17?-ethinyl estradiol (EE2), and phenanthrene (Phe). The results showed significant sediment organic matter (SOM) decomposition during the incubation, and the SOM decay and transformation had a profound impact on the adsorption of organic compounds by the sediment. An increasing-delay-increasing pattern of change was observed for the SOM normalized partition coefficients of EE2 and Phe. This change was accordant to the transformation of SOM from labile organics into active biomass and its microbial products, and finally into more condensed and humic-like substances. Comparison between the 3 model micropollutants indicates that the chemical adsorption behaviors were mostly affected by their hydrophobic properties. PMID:24929636

Fei, Ying-heng; Xing, Baoshan; Li, Xiao-yan

2014-09-01

411

Steganography based on pixel intensity value decomposition  

NASA Astrophysics Data System (ADS)

This paper focuses on steganography based on pixel intensity value decomposition. A number of existing schemes such as binary, Fibonacci, Prime, Natural, Lucas, and Catalan-Fibonacci (CF) are evaluated in terms of payload capacity and stego quality. A new technique based on a specific representation is proposed to decompose pixel intensity values into 16 (virtual) bit-planes suitable for embedding purposes. The proposed decomposition has a desirable property whereby the sum of all bit-planes does not exceed the maximum pixel intensity value, i.e. 255. Experimental results demonstrate that the proposed technique offers an effective compromise between payload capacity and stego quality of existing embedding techniques based on pixel intensity value decomposition. Its capacity is equal to that of binary and Lucas, while it offers a higher capacity than Fibonacci, Prime, Natural, and CF when the secret bits are embedded in 1st Least Significant Bit (LSB). When the secret bits are embedded in higher bit-planes, i.e., 2nd LSB to 8th Most Significant Bit (MSB), the proposed scheme has more capacity than Natural numbers based embedding. However, from the 6th bit-plane onwards, the proposed scheme offers better stego quality. In general, the proposed decomposition scheme has less effect in terms of quality on pixel value when compared to most existing pixel intensity value decomposition techniques when embedding messages in higher bit-planes.

Abdulla, Alan Anwar; Sellahewa, Harin; Jassim, Sabah A.

2014-05-01

412

Estimating Litter Decomposition Rate in Single-Pool Models Using Nonlinear Beta Regression  

PubMed Central

Litter decomposition rate (k) is typically estimated from proportional litter mass loss data using models that assume constant, normally distributed errors. However, such data often show non-normal errors with reduced variance near bounds (0 or 1), potentially leading to biased k estimates. We compared the performance of nonlinear regression using the beta distribution, which is well-suited to bounded data and this type of heteroscedasticity, to standard nonlinear regression (normal errors) on simulated and real litter decomposition data. Although the beta model often provided better fits to the simulated data (based on the corrected Akaike Information Criterion, AICc), standard nonlinear regression was robust to violation of homoscedasticity and gave equally or more accurate k estimates as nonlinear beta regression. Our simulation results also suggest that k estimates will be most accurate when study length captures mid to late stage decomposition (50–80% mass loss) and the number of measurements through time is ?5. Regression method and data transformation choices had the smallest impact on k estimates during mid and late stage decomposition. Estimates of k were more variable among methods and generally less accurate during early and end stage decomposition. With real data, neither model was predominately best; in most cases the models were indistinguishable based on AICc, and gave similar k estimates. However, when decomposition rates were high, normal and beta model k estimates often diverged substantially. Therefore, we recommend a pragmatic approach where both models are compared and the best is selected for a given data set. Alternatively, both models may be used via model averaging to develop weighted parameter estimates. We provide code to perform nonlinear beta regression with freely available software. PMID:23049771

Laliberté, Etienne; Adair, E. Carol; Hobbie, Sarah E.

2012-01-01

413

The Effect of the Crayfish Orconectes virilis (Crustacea: Decapoda: Cambaridae) in the Decomposition and Succession of Submerged Small Mammal Carrion  

NASA Astrophysics Data System (ADS)

The role of the crayfish Orconectes virilis in the decomposition of submerged rat carrion and succession of other benthic macroinvertebrates was experimentally investigated in Slaughterhouse Gulch, a small, urban stream in Littleton, Colorado. Crayfish participation in carrion decomposition significantly altered the decomposition rate of the carrion. Nine carcasses were exposed in anchored minnow traps at three degrees of crayfish access: crayfish always present, crayfish having free access, and crayfish excluded. These three treatments required 23 days, 29 days, and 65 days, respectively, for complete decomposition of the rat carrion (<2% original biomass). Sample variability increased with number of crayfish present, especially as decomposition proceeded. Seven other macroinvertebrate taxa were collected from the carcasses, but their presence or absence could not be correlated with crayfish presence. The leech Haemopis marmoratus was generally the first macroinvertebrate to arrive at the carrion, being present in densities of <5 individuals/carcass early in succession and in larger densities (up to 25 individuals/carcass) after extensive decomposition and exposure of the viscera.

de Jong, G. D.; Chadwick, J. W.

2005-05-01

414

Nutritional Findings and Early Behavioral Observations.  

ERIC Educational Resources Information Center

This study investigated the effects of a short period of severe protein malnutrition on subsequent growth and development in the squirrel monkey. A total of 12 newborn monkeys were fed a low protein diet from 2 to 8 weeks of age then rehabilitated by returning them to the 13 percent protein diet of the control group. Minimum amount of protein…

Ausman, Lynn M.

415

Comparison of different methods to determine the degree of peat decomposition in peat bogs  

NASA Astrophysics Data System (ADS)

Peat humification or decomposition is a frequently used proxy to extract past time changes in hydrology and climate from peat bogs. During the past century several methods to determine changes in peat decomposition have been introduced. Most of these methods are operationally defined only and the chemical changes underlying the decomposition process are often poorly understood and lack validation. Due to the chemically undefined nature of many humification analyses the comparison of results obtained by different methods is difficult if not misleading. In this study we compared changes in peat decomposition in cores of two peat bogs (Königsmoor (KK), Kleines Rotes Bruch, KRB) from the Harz Mountains (Germany) using C / N ratios, Fourier Transform Infrared spectra absorption (FTIR) intensities, Rock Eval® oxygen- and hydrogen indices, ?13C and ?15N isotopic signatures and UV-absorption of NaOH peat extracts. In addition, one of the cores was analysed for changes in the peat's molecular composition using pyrolysis gas chromatography mass spectrometry (pyrolysis-GC-MS). Records of decomposition proxies show similar historical development at both sites, indicating external forcing such as climate as controlling process. Moreover, all decomposition proxies except UV-ABS and ?15N isotopes show similar patterns in their records and thus reflect in different extents signals of decomposition. Pyrolysis-GC-MS analyses of the KK core reveal that changes in peat molecular chemistry are mainly attributed to decomposition processes and to a lesser extend to changes in vegetation. Changes in the abundance of molecular compounds indicate that peat decomposition in the KK bog is mainly characterized by preferential decomposition of phenols and polysaccharides and relative enrichment of aliphatics during drier periods. Enrichment of lignin and other aromatics during decomposition was also observed but showed less variation, and presumably reflects changes in vegetation associated to changes in hydrology of the bogs. Significant correlations with polysaccharide and aliphatic pyrolysis products were found for C / N ratios, FTIR-band intensities and for hydrogen index values, supporting that these decomposition indices provide reasonable information despite their bulk nature. Correlation with oxygen index values and ?13C was weaker assumingly indicating carboxylation of the peat during drier periods and enrichment of isotopically lighter peat components during decomposition, respectively. FTIR, C / N ratio, Pyrolysis-GC-MS analyses and Rock Eval hydrogen indices appear to reflect mass loss and related changes in the molecular peat composition during mineralization best. Different to the other investigated proxies, Pyrolysis-GC-MS and FTIR analyses allow disentangling decomposition processes and vegetation changes. UV-ABS measurements of alkaline peat extracts show only weak correlation with other decomposition proxiesas they mainly reflect the formation of humic acids through humifcation and to a~lesser extend mass loss during mineralization.

Biester, H.; Knorr, K.-H.; Schellekens, J.; Basler, A.; Hermanns, Y.-M.

2013-11-01

416

Randomized interpolative decomposition of separated representations  

NASA Astrophysics Data System (ADS)

We introduce an algorithm to compute tensor interpolative decomposition (dubbed CTD-ID) for the reduction of the separation rank of Canonical Tensor Decompositions (CTDs). Tensor ID selects, for a user-defined accuracy ?, a near optimal subset of terms of a CTD to represent the remaining terms via a linear combination of the selected terms. CTD-ID can be used as an alternative to or in combination with the Alternating Least Squares (ALS) algorithm. We present examples of its use within a convergent iteration to compute inverse operators in high dimensions. We also briefly discuss the spectral norm as a computational alternative to the Frobenius norm in estimating approximation errors of tensor ID. We reduce the problem of finding tensor IDs to that of constructing interpolative decompositions of certain matrices. These matrices are generated via randomized projection of the terms of the given tensor. We provide cost estimates and several examples of the new approach to the reduction of separation rank.

Biagioni, David J.; Beylkin, Daniel; Beylkin, Gregory

2015-01-01

417

Domain Decomposition for Heterojunction Problems in Semiconductors  

E-print Network

We present a domain decomposition approach for the simulation of charge transport in heterojunction semiconductors. The problem is characterized by a large variation of primary variables across an interface region of a size much smaller than the device scale, and requires a multiscale approach in which that region is modeled as an internal boundary. The model combines drift diffusion equations on subdomains coupled by thermionic emission heterojunction model on the interface which involves a nonhomogeneous jump computed at fine scale with Density Functional Theory. Our full domain decomposition approach extends our previous work for the potential equation only, and we present perspectives on its HPC implementation. The model can be used, e.g., for the design of higher efficiency solar cells for which experimental results are not available. More generally, our algorithm is naturally parallelizable and is a new domain decomposition paradigm for problems with multiscale phenomena associated with internal interfa...

Costa, Timothy; Peszynska, Malgorzata

2014-01-01

418

Multilevel domain decomposition for electronic structure calculations  

SciTech Connect

We introduce a new multilevel domain decomposition method (MDD) for electronic structure calculations within semi-empirical and density functional theory (DFT) frameworks. This method iterates between local fine solvers and global coarse solvers, in the spirit of domain decomposition methods. Using this approach, calculations have been successfully performed on several linear polymer chains containing up to 40,000 atoms and 200,000 atomic orbitals. Both the computational cost and the memory requirement scale linearly with the number of atoms. Additional speed-up can easily be obtained by parallelization. We show that this domain decomposition method outperforms the density matrix minimization (DMM) method for poor initial guesses. Our method provides an efficient preconditioner for DMM and other linear scaling methods, variational in nature, such as the orbital minimization (OM) procedure.

Barrault, M. [EDF R and D, 1 avenue du General de Gaulle, 92141 Clamart Cedex (France) and CERMICS, Ecole Nationale des Ponts et Chaussees, 6 and 8, Avenue Blaise Pascal, Cite Descartes, 77455 Marne-La-Vallee Cedex 2 (France)]. E-mail: maxime.barrault@edf.fr; Cances, E. [CERMICS, Ecole Nationale des Ponts et Chaussees, 6 and 8, Avenue Blaise Pascal, Cite Descartes, 77455 Marne-La-Vallee Cedex 2 (France)]. E-mail: cances@cermics.enpc.fr; Hager, W.W. [Department of Mathematics, University of Florida, Gainesville, FL 32611-8105 (United States)]. E-mail: hager@math.ufl.edu; Le Bris, C. [CERMICS, Ecole Nationale des Ponts et Chaussees, 6 and 8, Avenue Blaise Pascal, Cite Descartes, 77455 Marne-La-Vallee Cedex 2 (France)]. E-mail: lebris@cermics.enpc.fr

2007-03-01

419

The spectra of the multicharged argon hollow ions: Observation, modeling and using for diagnostics of the early stage of the heating of clusters by a super high contrast femtosecond laser pulses  

SciTech Connect

A study is made of the ultra-short laser pulse irradiation of Ar cluster targets. Experiments have been performed with large cluster sizes and using very high laser contrasts, which have allowed clear and unambiguous observation of exotic inner-shell transitions in near-neutral Ar ions. The interaction of the main laser pulse with the unperturbed target is a necessary requirement for observing these lines. Our measurements are supported by kinetics calculations in which a very detailed atomic model is used. The calculations predict all of the spectral features found experimentally, and support the notion that the X-ray emission arises from many ion stages of the Ar plasma, from near-neutral through He-like ions, and from a range of plasma temperatures and densities. Differences between X-ray argon clusters excited at the laser-cluster and laser-droplet interactions have been analyzed. X-ray spectral methods have been proposed to determine the parameters of the plasma formed at the early stages of its evolution. It has been shown that the spectra of hollow ions are the most informative in the first moments of the heating of a cluster, whereas the diagnostics of the late stages can be performed using the conventional lines of multicharged ions.

Pikuz, T. A.; Faenov, A. Ya.; Skobelev, I. Yu.; Fortov, V. E.; Boldarev, A. S.; Gasilov, V. A.; Chen, L. M.; Zhang, L.; Yan, W. C.; Yuan, D. W.; Mao, J. Y.; Wang, Z. H.; Colgan, J.; Abdallah, J. Jr.; Fukuda, Y.; Hayashi, Y.; Pirozhkov, A.; Kawase, K.; Shimomura, T.; Kiriyama, H. [Joint Institute for High Temperatures, Russian Academy of Sciences, Izhorskaya 13 bld.2, Moscow, 125412 (Russian Federation) and Quantum Beam Science Directorate, Japan Atomic Energy Agency, 8-1-7 Umemidai Kizugawa, Kyoto 619-0215 (Japan); Joint Institute for High Temperatures, Russian Academy of Sciences, Izhorskaya 13 bld.2, Moscow, 125412 (Russian Federation); Institute of Mathematical Modeling, Russian Academy of Sciences, Miusskaya pl. 4a, Moscow, 125047 (Russian Federation); Institute of Physics, Chinese Academy of Sciences, Beijing, 100190 (China); Los Alamos National Laboratory, NM 87545 Los Alamos (United States); Quantum Beam Science Directorate, Japan Atomic Energy Agency, 8-1-7 Umemidai Kizugawa, Kyoto 619-0215 (Japan); Graduate School for the Creation of New Photonics Industries, Hamamatsu, Shizuoka 431-1202 (Japan); Quantum Beam Science Directorate, Japan Atomic Energy Agency, 8-1-7 Umemidai Kizugawa, Kyoto 619-0215 (Japan); and others

2012-07-11

420

Error reduction in EMG signal decomposition.  

PubMed

Decomposition of the electromyographic (EMG) signal into constituent action potentials and the identification of individual firing instances of each motor unit in the presence of ambient noise are inherently probabilistic processes, whether performed manually or with automated algorithms. Consequently, they are subject to errors. We set out to classify and reduce these errors by analyzing 1,061 motor-unit action-potential trains (MUAPTs), obtained by decomposing surface EMG (sEMG) signals recorded during human voluntary contractions. Decomposition errors were classified into two general categories: location errors representing variability in the temporal localization of each motor-unit firing instance and identification errors consisting of falsely detected or missed firing instances. To mitigate these errors, we developed an error-reduction algorithm that combines multiple decomposition estimates to determine a more probable estimate of motor-unit firing instances with fewer errors. The performance of the algorithm is governed by a trade-off between the yield of MUAPTs obtained above a given accuracy level and the time required to perform the decomposition. When applied to a set of sEMG signals synthesized from real MUAPTs, the identification error was reduced by an average of 1.78%, improving the accuracy to 97.0%, and the location error was reduced by an average of 1.66 ms. The error-reduction algorithm in this study is not limited to any specific decomposition strategy. Rather, we propose it be used for other decomposition methods, especially when analyzing precise motor-unit firing instances, as occurs when measuring synchronization. PMID:25210159

Kline, Joshua C; De Luca, Carlo J

2014-12-01