Science.gov

Sample records for comparing observed growth

  1. Comparing NDVI and observed stem growth and wood density in forests of Northern Eurasia

    NASA Astrophysics Data System (ADS)

    Hughes, M. K.; Bunn, A. G.; Kirdyanov, A. V.; Shishov, V.; Losleben, M. V.; Oltchev, A.; Kuznetsova, E.; Novenko, E.

    2012-12-01

    To what extent does NDVI (Normalized Difference Vegetation Index) observed from space co-vary with directly observed stem radial increment and latewood density? To address this question we made correlation analyses between NDVI and paired tree-ring width (TRW) and maximum latewood density (MXD) records from 19 locations North of 54 degrees in the Russian Federation. The period of temporal overlap between the three sets of records started in 1981 and ended between 18 and 28 years later. We compared monthly NDVI at 8 km resolution for a region 24X24 km around each of the 19 locations with well-replicated TRW and MXD time series. Maximum correlation most often occurred in July of the current year, and was similar for both TRW (mean 0.34, minimum 0.04, maximum 0.63) and MXD (mean 0.31, min 0.09, max 0.61). There was a tendency for July correlations to be greatest with larch TRW and lower for spruce and pine TRW, with MXD following a similar pattern. Also, the greater the mean correlation ('rbar') between the component samples making up a location's mean tree ring time series, the greater that series' correlation with NDVI tended to be. We conclude that at the locations studied, which we believe to represent quite a large portion of the boreal forest, NDVI does co-vary with directly observed stem radial increment and latewood density, but to a rather modest degree. We will discuss the implications of our findings for the use of both data types, NDVI and tree rings, in tracking forest productivity on large spatial scales.

  2. Growth data of underprivileged children living in rural areas of Chin State, Burma/Myanmar, compared to the WHO reference growth standards: an observational study

    PubMed Central

    Prenkert, Malin; Ehnfors, Margareta

    2016-01-01

    Objectives To explore growth data (height-for-age, weight-for-age and BMI-for-age) of children living in poor socioeconomic conditions in rural areas of Chin State, Burma/Myanmar; and to compare these data with the growth and development z-score (GDZ) values for school-aged children and adolescents, provided by the WHO. Setting A support and educational programme, run by the Swedish association Chin Development and Research Society (CDRS), was carried out among underprivileged school-aged children, unable to attend school without economic and practical support, living in villages and remote areas in Chin State. Participants Community leaders who were well familiar with the citizens in the community identified children in need of this support. Other community members could also suggest or apply for this. The sample includes all participating children in the CDRS programme at the time of the data collection in six townships. The children were placed in host families, close to a suitable school. Two samples with a total of 639 children from 144 villages and remote areas were obtained: 1. Children in the CDRS Chin Programme (CCP) (2007–2010) comprised 558 children: 50% girls and boys. 2. Children in the Chin Society (CCS) (2010) comprised 81 children: 44% girls and 56% boys. Primary outcome measures Growth data. Results All growth data from both groups deviated significantly from the WHO standard references (p≤0.001). The prevalence of stunting (height-for-age ≤–2SD) was 52% among girls and 68% among boys. High levels of wasting (weight-for-age ≤–2SD) were found among girls 29% and boys 36% aged 5–10 years. In addition, severe thinness (BMI-for-age ≤–2SD) was found among girls 31% and boys 44%, all results to be compared to the expected 2.27%. Conclusions Many more than expected—according to the WHO reference values—in CCP and CCS suffered from stunting, wasting and thinness. PMID:26787249

  3. Observations on nocturnal growth of atmospheric clusters

    NASA Astrophysics Data System (ADS)

    Junninen, Heikki; Hulkkonen, Mira; Riipinen, Ilona; Nieminen, Tuomo; Hirsikko, Anne; Suni, Tanja; Boy, Michael; Lee, Shan-Hu; Vana, Marko; Tammet, Hannes; Kerminen, Veli-Matti; Kulmala, Markku

    2008-07-01

    In this paper, we summarize recent observations of nighttime nucleation events observed during 4 yr, from 2003 to 2006, at the SMEAR II station in Hyytiälä, southern Finland. Formation of new atmospheric aerosol particles has been frequently observed all around the world in daytime, but similar observations in nighttime are rare. The recently developed ion spectrometers enabled us to measure charged aerosol particles and ion clusters to diameters <1 nm and are efficient tools for evaluating cluster dynamics during nighttime. We observed clear growth of cluster ions during approximately 60 nights per yr. The newly formed intermediate ions usually persisted for several hours with typical concentrations of 100-200 cm-3. The evolution of nighttime growth events is different compared with daytime events. The mechanism behind nighttime events is still unclear, but the behaviour can be described by the hypothesis of activation of clusters.

  4. Comparing Two Approaches for Assessing Observation Impact

    NASA Technical Reports Server (NTRS)

    Todling, Ricardo

    2013-01-01

    Langland and Baker introduced an approach to assess the impact of observations on the forecasts. In that approach, a state-space aspect of the forecast is defined and a procedure is derived ultimately relating changes in the aspect with changes in the observing system. Some features of the state-space approach are to be noted: the typical choice of forecast aspect is rather subjective and leads to incomplete assessment of the observing system, it requires availability of a verification state that is in practice correlated with the forecast, and it involves the adjoint operator of the entire data assimilation system and is thus constrained by the validity of this operator. This article revisits the topic of observation impacts from the perspective of estimation theory. An observation-space metric is used to allow inferring observation impact on the forecasts without the limitations just mentioned. Using differences of observation-minus-forecast residuals obtained from consecutive forecasts leads to the following advantages: (i) it suggests a rather natural choice of forecast aspect that directly links to the data assimilation procedure, (ii) it avoids introducing undesirable correlations in the forecast aspect since verification is done against the observations, and (iii) it does not involve linearization and use of adjoints. The observation-space approach has the additional advantage of being nearly cost free and very simple to implement. In its simplest form it reduces to evaluating the statistics of observationminus- background and observation-minus-analysis residuals with traditional methods. Illustrations comparing the approaches are given using the NASA Goddard Earth Observing System.

  5. Observations of EMIC Wave Growth by MMS

    NASA Astrophysics Data System (ADS)

    Paulson, K. W.; Argall, M. R.; Torbert, R. B.; Smith, C. W.; Fuselier, S. A.; Pollock, C. J.; Giles, B. L.; Burch, J. L.; Glassmeier, K. H.; Auster, H. U.

    2015-12-01

    Electromagnetic Ion Cyclotron (EMIC) waves are a prevalent wave mode in the Earth's magnetosphere. The active regions responsible for the generation of these waves have been observed using both ground-based and in situ data on a statistical scale. These regions have been shown to persist for time periods on the order of 10s of minutes to several hours, but their initial growth phase is difficult to characterize. The Magnetospheric Multiscale (MMS) mission, comprised of four closely-separated identical spacecraft, have made several observations of the growth phase of these active regions as subsequent spacecraft pass through the same area. The full suite of particle and field instruments on board the MMS spacecraft allow us to characterize the growth conditions which lead to EMIC wave enhancements.

  6. Comparing InSAR observations of incremental fault growth in the 2005-2010 Dabbahu (Ethiopia) rifting episode with cumulative displacement-length measurements from high-resolution LiDAR

    NASA Astrophysics Data System (ADS)

    Hofmann, B.; Wright, T.; Paton, D. A.; Rowland, J. V.; Vye, C.

    2012-12-01

    out in October 2009 covering the central section of the Dabbahu segment. The resulting DEM covers 800 km2 with, on average, one return every 4 m{2}, but including areas with 1 return per 0.25 m2. The height accuracy of the DEM is ˜ 10 cm. We identify the slipped structures by calculating the gradient of the unwrapped deformation. Once the structures have been identified and roughly picked we apply our new algorithm to pick hanging and footwall cut-offs along the surface faults and extract their displacement-length profiles from the LiDAR. At the same time we automatically extract the incremental line-of-sight fault offsets from the InSAR data, converting these into vertical throw using an average sense of motion on the faults. By comparing these two measurements we can directly measure how faults are growing, and test models of fault growth and linkage. During each event we observe reactivation of faults along the entire length of the dike with several 10s of fault segments involved in each case. We can further see that the deformation is not just located along the obvious surface faults but that a considerable amount is located on buried structures.

  7. Hemispheric Coupling: Comparing Dynamo Simulations and Observations

    NASA Astrophysics Data System (ADS)

    Norton, A. A.; Charbonneau, P.; Passos, D.

    2014-12-01

    Numerical simulations that reproduce solar-like magnetic cycles can be used to generate long-term statistics. The variations in north-south hemispheric solar cycle synchronicity and amplitude produced in simulations has not been widely compared to observations. The observed limits on solar cycle amplitude and phase asymmetry show that hemispheric sunspot area production is no more than 20 % asymmetric for cycles 17-23 and that phase lags do not exceed 20 % (or two years) of the total cycle period, as determined from Royal Greenwich Observatory sunspot data. Several independent studies have found a long-term trend in phase values as one hemisphere leads the other for, on average, four cycles. Such persistence in phase is not indicative of a stochastic phenomenon. We compare these observational findings to the magnetic cycle found in a numerical simulation of solar convection recently produced with the EULAG-MHD model. This long "millennium simulation" spans more than 1600 years and generated 40 regular, sunspot-like cycles. While the simulated cycle length is too long (˜40 yrs) and the toroidal bands remain at too high of latitudes (>30°), some solar-like aspects of hemispheric asymmetry are reproduced. The model is successful at reproducing the synchrony of polarity inversions and onset of cycle as the simulated phase lags do not exceed 20 % of the cycle period. The simulated amplitude variations between the north and south hemispheres are larger than those observed in the Sun, some up to 40 %. An interesting note is that the simulations also show that one hemisphere can persistently lead the other for several successive cycles, placing an upper bound on the efficiency of transequatorial magnetic coupling mechanisms. These include magnetic diffusion, cross-equatorial mixing within latitudinally-elongated convective rolls (a.k.a. "banana cells") and transequatorial meridional flow cells. One or more of these processes may lead to magnetic flux cancellation whereby

  8. Comparing graphene growth on Cu(111) versus oxidized Cu(111).

    PubMed

    Gottardi, Stefano; Müller, Kathrin; Bignardi, Luca; Moreno-López, Juan Carlos; Pham, Tuan Anh; Ivashenko, Oleksii; Yablonskikh, Mikhail; Barinov, Alexei; Björk, Jonas; Rudolf, Petra; Stöhr, Meike

    2015-02-11

    The epitaxial growth of graphene on catalytically active metallic surfaces via chemical vapor deposition (CVD) is known to be one of the most reliable routes toward high-quality large-area graphene. This CVD-grown graphene is generally coupled to its metallic support resulting in a modification of its intrinsic properties. Growth on oxides is a promising alternative that might lead to a decoupled graphene layer. Here, we compare graphene on a pure metallic to graphene on an oxidized copper surface in both cases grown by a single step CVD process under similar conditions. Remarkably, the growth on copper oxide, a high-k dielectric material, preserves the intrinsic properties of graphene; it is not doped and a linear dispersion is observed close to the Fermi energy. Density functional theory calculations give additional insight into the reaction processes and help explaining the catalytic activity of the copper oxide surface. PMID:25611528

  9. Comparing Graphene Growth on Cu(111) versus Oxidized Cu(111)

    PubMed Central

    2015-01-01

    The epitaxial growth of graphene on catalytically active metallic surfaces via chemical vapor deposition (CVD) is known to be one of the most reliable routes toward high-quality large-area graphene. This CVD-grown graphene is generally coupled to its metallic support resulting in a modification of its intrinsic properties. Growth on oxides is a promising alternative that might lead to a decoupled graphene layer. Here, we compare graphene on a pure metallic to graphene on an oxidized copper surface in both cases grown by a single step CVD process under similar conditions. Remarkably, the growth on copper oxide, a high-k dielectric material, preserves the intrinsic properties of graphene; it is not doped and a linear dispersion is observed close to the Fermi energy. Density functional theory calculations give additional insight into the reaction processes and help explaining the catalytic activity of the copper oxide surface. PMID:25611528

  10. Observational constraints on modified Chaplygin gas from cosmic growth

    SciTech Connect

    Paul, B.C.; Thakur, P. E-mail: prasenjit_thakur1@yahoo.co.in

    2013-11-01

    We investigate the linear growth function for the large scale structures of the universe considering modified Chaplygin gas as dark energy. Taking into account observational growth data for a given range of redshift from the Wiggle-Z measurements and rms mass fluctuations from Ly-α measurements we numerically analyze cosmological models to constrain the parameters of the MCG. The observational data of Hubble parameter with redshift z is also considered. The Wang-Steinhardt ansatz for growth index γ and growth function f (defined as f = Ω{sub m}{sup γ}(a)) are considered for the numerical analysis. The best-fit values of the equation of state parameters obtained here is employed to study the growth function (f), growth index (γ) and equation of state (ω) with redshift z. The observational constraints on MCG parameters obtained here are compared with that of the GCG model for viable cosmology. It is noted that MCG also satisfactorily accommodates an accelerating phase followed by a matter dominated phase of the universe.

  11. Comparing MMS Observations with Theory and Simulation

    NASA Astrophysics Data System (ADS)

    Moore, Thomas Earle; Burch, James L.; Torbert, Roy B.

    2016-04-01

    MMS completes its first year in orbit on 13 March 2016, and its science data set will by then be open to use by the entire research community, including theorists and simulators. We will briefly summarize observational highlights from the first year of MMS operations to illustrate the unprecedented accuracy and resolution of phenomena that have until now been inaccessible to observation, especially at electron scales. The goal of such observations has always been to test and refine our understanding of reconnection, as embodied in our theoretical and simulation models, with the goal of better predicting the morphology and dynamic evolution of reconnection as a driver of space weather. Toward that end, we summarize the MMS data products and suggest ways for the theory and modeling community to make contact with MMS observations and use them to test their models.

  12. Comparative Study of Bacterial Growth in Magnet Fields

    NASA Astrophysics Data System (ADS)

    Smith, Derek; Masood, Samina

    It has been shown that magnetic fields affect bacterial growth. A comparative study of growth rates for gram-positive and gram-negative bacteria with different types of magnetic fields is done. Special focus is placed upon growth within liquid media, and the effect of magnetic fields relative to the chosen growth medium is considered.

  13. Roles of Naturalistic Observation in Comparative Psychology

    ERIC Educational Resources Information Center

    Miller, David B.

    1977-01-01

    "Five roles are considered by which systematic, quantified field research can augment controlled laboratory experimentation in terms of increasing the validity of laboratory studies." Advocates that comparative psychologists should "take more initiative in designing, executing, and interpreting our experiments with regard to the natural history of…

  14. Comparative Views of Arctic Sea Ice Growth

    NASA Technical Reports Server (NTRS)

    2000-01-01

    NASA researchers have new insights into the mysteries of Arctic sea ice, thanks to the unique abilities of Canada's Radarsat satellite. The Arctic is the smallest of the world's four oceans, but it may play a large role in helping scientists monitor Earth's climate shifts.

    Using Radarsat's special sensors to take images at night and to peer through clouds, NASA researchers can now see the complete ice cover of the Arctic. This allows tracking of any shifts and changes, in unprecedented detail, over the course of an entire winter. The radar-generated, high-resolution images are up to 100 times better than those taken by previous satellites.

    The two images above are separated by nine days (earlier image on the left). Both images represent an area (approximately 96 by 128 kilometers; 60 by 80 miles)located in the Baufort Sea, north of the Alaskan coast. The brighter features are older thicker ice and the darker areas show young, recently formed ice. Within the nine-day span, large and extensive cracks in the ice cover have formed due to ice movement. These cracks expose the open ocean to the cold, frigid atmosphere where sea ice grows rapidly and thickens.

    Using this new information, scientists at NASA's Jet Propulsion Laboratory (JPL), Pasadena, Calif., can generate comprehensive maps of Arctic sea ice thickness for the first time. 'Before we knew only the extent of the ice cover,' said Dr. Ronald Kwok, JPL principal investigator of a project called Sea Ice Thickness Derived From High Resolution Radar Imagery. 'We also knew that the sea ice extent had decreased over the last 20 years, but we knew very little about ice thickness.'

    'Since sea ice is very thin, about 3 meters (10 feet) or less,'Kwok explained, 'it is very sensitive to climate change.'

    Until now, observations of polar sea ice thickness have been available for specific areas, but not for the entire polar region.

    The new radar mapping technique has also given scientists a close look at

  15. Comparative Views of Arctic Sea Ice Growth

    NASA Technical Reports Server (NTRS)

    2000-01-01

    NASA researchers have new insights into the mysteries of Arctic sea ice, thanks to the unique abilities of Canada's Radarsat satellite. The Arctic is the smallest of the world's four oceans, but it may play a large role in helping scientists monitor Earth's climate shifts.

    Using Radarsat's special sensors to take images at night and to peer through clouds, NASA researchers can now see the complete ice cover of the Arctic. This allows tracking of any shifts and changes, in unprecedented detail, over the course of an entire winter. The radar-generated, high-resolution images are up to 100 times better than those taken by previous satellites.

    The two images above are separated by nine days (earlier image on the left). Both images represent an area (approximately 96 by 128 kilometers; 60 by 80 miles)located in the Baufort Sea, north of the Alaskan coast. The brighter features are older thicker ice and the darker areas show young, recently formed ice. Within the nine-day span, large and extensive cracks in the ice cover have formed due to ice movement. These cracks expose the open ocean to the cold, frigid atmosphere where sea ice grows rapidly and thickens.

    Using this new information, scientists at NASA's Jet Propulsion Laboratory (JPL), Pasadena, Calif., can generate comprehensive maps of Arctic sea ice thickness for the first time. 'Before we knew only the extent of the ice cover,' said Dr. Ronald Kwok, JPL principal investigator of a project called Sea Ice Thickness Derived From High Resolution Radar Imagery. 'We also knew that the sea ice extent had decreased over the last 20 years, but we knew very little about ice thickness.'

    'Since sea ice is very thin, about 3 meters (10 feet) or less,'Kwok explained, 'it is very sensitive to climate change.'

    Until now, observations of polar sea ice thickness have been available for specific areas, but not for the entire polar region.

    The new radar mapping technique has also given scientists a close look at

  16. Plant development in space: Observations on root formation and growth

    NASA Technical Reports Server (NTRS)

    Levine, H. G.; Kann, R. P.; Krikorian, Abraham D.

    1990-01-01

    Root growth in space is discussed and observations on root production from plants flown as part of the Chromex project that were defined as to their origin, stage of development and physiological status, are presented. Roots were generated from fully differentiated, aseptically maintained individuals of Haplopappus gracilis (Compositae) under spaceflight conditions. Results are compared for tissue culture generated plantlets and comparably sized seedling clone individuals, both of which had their roots trimmed on Earth before they were loaded into NASA's plant growth unit and subjected to a 5 day shuttle flight (STS-29). Asepsis was maintained throughout the experiment. Overall root production was 40 to 50 percent greater under spaceflight conditions than during ground control tests. However, root formation slowed down towards the end of the flight. This decrease in new roots did not occur in the ground controls that sought to simulate flight except for microgravity.

  17. Direct Observation of Transient Surface Species during Ge Nanowire Growth and Their Influence on Growth Stability.

    PubMed

    Sivaram, Saujan V; Shin, Naechul; Chou, Li-Wei; Filler, Michael A

    2015-08-12

    Surface adsorbates are well-established choreographers of material synthesis, but the presence and impact of these short-lived species on semiconductor nanowire growth are largely unknown. Here, we use infrared spectroscopy to directly observe surface adsorbates, hydrogen atoms and methyl groups, chemisorbed to the nanowire sidewall and show they are essential for the stable growth of Ge nanowires via the vapor-liquid-solid mechanism. We quantitatively determine the surface coverage of hydrogen atoms during nanowire growth by comparing ν(Ge-H) absorption bands from operando measurements (i.e., during growth) to those after saturating the nanowire sidewall with hydrogen atoms. This method provides sub-monolayer chemical information at relevant reaction conditions while accounting for the heterogeneity of sidewall surface sites and their evolution during elongation. Our findings demonstrate that changes to surface bonding are critical to understand Ge nanowire synthesis and provide new guidelines for rationally selecting catalysts, forming heterostructures, and controlling dopant profiles. PMID:26147949

  18. Fatigue crack growth theory and experiment: A comparative analysis

    SciTech Connect

    Sananda, K.

    1983-12-01

    A number of theoretical models have been proposed in the literature which explain the second or the fourth power dependence of fatigue crack growth rate on ..delta..K, the stress intensity factor range in the Paris-Erdogan relation da/dN = C ..delta..K /SUP m/ . All of these models pertain to the intermediate range of crack growth rates where the m values are relatively low in the range of 2 to 4. The values of m for many metals and alloys can be much larger than 4 at near threshold crack growth rates or at stress intensities close to the fast fracture, and in some cases throughout the range of ..delta..K when the faceted mode of crack growth occurs. For such cases, the models appear to have no relevance. In this report predictions of different theoretical models are critically examined in comparison to experimentally determined crack growth rates in a MA 956, oxide dispersion strengthened alloy. Cumulative damage models predict crack growth rates reasonably well except in the range where ductile striations are observed. Lack of agreement with any particular model in this range is related to the fact that at different regions across the specimen thickness different mechanisms, either plastic blunting or cumulative damage, control the crack growth.

  19. Growth hormone in the eye: A comparative update.

    PubMed

    Harvey, Steve; Martínez-Moreno, Carlos G; Ávila-Mendoza, José; Luna, Maricela; Arámburo, Carlos

    2016-08-01

    Comparative studies have previously established that the eye is an extrapituitary site of growth hormone (GH) production and action in fish, amphibia, birds and mammals. In this review more recent literature and original data in this field are considered. PMID:26828817

  20. Observation of Single Colloidal Platinum Nanocrystal Growth Trajectories

    SciTech Connect

    Zheng, Haimei; Smith, Rachel; Jun, Young-wook; Kisielowski, Christian; Dahmen, Ulrich; Alivisatos, A. Paul

    2009-02-09

    It is conventionally assumed that the growth of monodisperse colloidal nanocrystals requires a temporally discrete nucleation followed by monomer attachment onto the existing nuclei. However, recent studies have reported violations of this classical growth model, and have suggested that inter-particle interactions are also involved during the growth. Mechanisms of nanocrystal growth still remain controversial. Using in situ transmission electron microscopy, we show that platinum nanocrystals can grow either by monomer attachment from solution onto the existing particles or by coalescence between the particles. Surprisingly, an initially broad size distribution of the nanocrystals can spontaneously narrow. We suggest that nanocrystals take different pathways of growth based on their size- and morphology-dependent internal energies. These observations are expected to be highly relevant for other nanocrystal systems.

  1. Direct observation of morphological evolution of a catalyst during carbon nanotube forest growth: new insights into growth and growth termination.

    PubMed

    Jeong, Seojeong; Lee, Jaegeun; Kim, Hwan-Chul; Hwang, Jun Yeon; Ku, Bon-Cheol; Zakharov, Dmitri N; Maruyama, Benji; Stach, Eric A; Kim, Seung Min

    2016-01-28

    In this study, we develop a new methodology for transmission electron microscopy (TEM) analysis that enables us to directly investigate the interface between carbon nanotube (CNT) arrays and the catalyst and support layers for CNT forest growth without any damage induced by a post-growth TEM sample preparation. Using this methodology, we perform in situ and ex situ TEM investigations on the evolution of the morphology of the catalyst particles and observe the catalyst particles to climb up through CNT arrays during CNT forest growth. We speculate that the lifted catalysts significantly affect the growth and growth termination of CNT forests along with Ostwald ripening and sub-surface diffusion. Thus, we propose a modified growth termination model which better explains various phenomena related to the growth and growth termination of CNT forests. PMID:26700058

  2. Direct observation of morphological evolution of a catalyst during carbon nanotube forest growth: new insights into growth and growth termination

    NASA Astrophysics Data System (ADS)

    Jeong, Seojeong; Lee, Jaegeun; Kim, Hwan-Chul; Hwang, Jun Yeon; Ku, Bon-Cheol; Zakharov, Dmitri N.; Maruyama, Benji; Stach, Eric A.; Kim, Seung Min

    2016-01-01

    In this study, we develop a new methodology for transmission electron microscopy (TEM) analysis that enables us to directly investigate the interface between carbon nanotube (CNT) arrays and the catalyst and support layers for CNT forest growth without any damage induced by a post-growth TEM sample preparation. Using this methodology, we perform in situ and ex situ TEM investigations on the evolution of the morphology of the catalyst particles and observe the catalyst particles to climb up through CNT arrays during CNT forest growth. We speculate that the lifted catalysts significantly affect the growth and growth termination of CNT forests along with Ostwald ripening and sub-surface diffusion. Thus, we propose a modified growth termination model which better explains various phenomena related to the growth and growth termination of CNT forests.In this study, we develop a new methodology for transmission electron microscopy (TEM) analysis that enables us to directly investigate the interface between carbon nanotube (CNT) arrays and the catalyst and support layers for CNT forest growth without any damage induced by a post-growth TEM sample preparation. Using this methodology, we perform in situ and ex situ TEM investigations on the evolution of the morphology of the catalyst particles and observe the catalyst particles to climb up through CNT arrays during CNT forest growth. We speculate that the lifted catalysts significantly affect the growth and growth termination of CNT forests along with Ostwald ripening and sub-surface diffusion. Thus, we propose a modified growth termination model which better explains various phenomena related to the growth and growth termination of CNT forests. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr05547d

  3. Polar cap plasma patch primary linear instability growth rates compared

    NASA Astrophysics Data System (ADS)

    Burston, Robert; Mitchell, Cathryn; Astin, Ivan

    2016-04-01

    Four primary plasma instability processes have been proposed in the literature to explain the generation of phase scintillation associated with polar cap plasma patches. These are the gradient drift, current convective, and Kelvin-Helmholtz instabilities and a small-scale "turbulence" process. In this paper the range of possible values of the linear growth rates for each of these processes is explored using Dynamics Explorer 2 satellite observations. It is found that the inertial turbulence instability is the dominant process, followed by inertial gradient drift, collisional turbulence, and collisional shortwave current convective instabilities. The other processes, such as Kelvin-Helmholtz, collisional gradient drift, and inertial shortwave current convective instabilities, very rarely (<1% of the time) give rise to a growth rate exceeding 1/60, that is deemed to be significant (in publications) to give rise to GPS scintillation.

  4. Comparative analysis of Staphylococcus aureus and Escherichia coli microcalorimetric growth

    PubMed Central

    2013-01-01

    Background Microcalorimetric bacterial growth studies have illustrated that thermograms differ significantly with both culture media and strain. The present contribution examines the possibility of discriminating between certain bacterial strains by microcalorimetry and the qualitative and quantitative contribution of the sample volume to the observed thermograms. Growth patterns of samples of Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922) were analyzed. Certain features of the thermograms that may serve to distinguish between these bacterial strains were identified. Results The thermograms of the two bacterial strains with sample volumes ranging from 0.3 to 0.7 ml and same initial bacterial concentration were analyzed. Both strains exhibit a roughly 2-peak shape that differs by peak amplitude and position along the time scale. Seven parameters corresponding to the thermogram key points related to time and heat flow values were proposed and statistically analyzed. The most relevant parameters appear to be the time to reach a heat flow of 0.05 mW (1.67 ± 0.46 h in E. coli vs. 2.99 ± 0.53 h in S. aureus, p < 0.0001), the time to reach the first peak (3.84 ± 0.5 h vs. 5.17 ± 0.49 h, p < 0.0001) and the first peak value (0.19 ± 0.02 mW vs. 0.086 ± 0.012 mW, p < 0.0001). The statistical analysis on 4 parameters of volume-normalized heat flow thermograms showed that the time to reach a volume-normalized heat flow of 0.1 mW/ml (1.75 ± 0.37 h in E. coli vs. 2.87 ± 0.65 h in S. aureus, p < 0.005), the time to reach the first volume-normalized peak (3.78 ± 0.47 h vs. 5.12 ± 0.52 h, p < 0.0001) and the first volume-normalized peak value (0.35 ± 0.05 mW/ml vs. 0.181 ± 0.040 mW/ml, p < 0.0001) seem to be the most relevant. Peakfit® decomposition and analysis of the observed thermograms complements the statistical analysis via quantitative arguments

  5. Direct Observation of Aggregative Nanoparticle Growth: Kinetic Modeling of the Size Distribution and Growth Rate

    SciTech Connect

    Woehl, Taylor J.; Park, Chiwoo; Evans, James E.; Arslan, Ilke; Ristenpart, William D.; Browning, Nigel D.

    2014-01-08

    Direct observations of solution-phase nanoparticle growth using in situ liquid transmission electron microscopy (TEM) have demonstrated the importance of “non-classical” growth mechanisms, such as aggregation and coalescence, on the growth and final morphology of nanocrystals at the atomic and single nanoparticle scales. To date, groups have quantitatively interpreted the mean growth rate of nanoparticles in terms of the Lifshitz-Slyozov-Wagner (LSW) model for Ostwald ripening, but less attention has been paid to modeling the corresponding particle size distribution. Here we use in situ fluid stage scanning TEM to demonstrate that silver nanoparticles grow by a length-scale dependent mechanism, where individual nanoparticles grow by monomer attachment but ensemble-scale growth is dominated by aggregation. Although our observed mean nanoparticle growth rate is consistent with the LSW model, we show that the corresponding particle size distribution is broader and more symmetric than predicted by LSW. Following direct observations of aggregation, we interpret the ensemble-scale growth using Smoluchowski kinetics and demonstrate that the Smoluchowski model quantitatively captures the mean growth rate and particle size distribution.

  6. Direct observation of episodic growth in an abyssal xenophyophore (Protista)

    NASA Astrophysics Data System (ADS)

    Gooday, A. J.; Bett, B. J.; Pratt, D. N.

    1993-11-01

    Three specimens of the xenophyophore Reticulammina labyrinthica were photographed on the Madeira Abyssal Plain (31°6.1'N, 21°10.9'W; 4944 m) using the Bathysnap time-lapse camera system. During the 8 month observation period, the specimens underwent an estimated 3-10 fold increase in volume. Growth occurred episodically in several distinct phases, each lasting 2-3 days, during which sediment was collected and incorporated into the test. These phases were separated by fairly regular periods of about 2 months when the organisms showed little obvious activity. The growth phases were approximately synchronous between specimens. However, it is not clear whether the periodicity and apparent synchronization of these events resulted from an external (environmental) cue or whether growth is internally controlled and the synchronization arose by chance. These unique observations, which represent the first direct measurement of growth in any abyssal organism living outside a hydrothermal vent field, suggest that xenophyophores combine test growth with deposit feeding. The tests appear to grow more quickly, and to be more active, dynamic structures, than previously believed.

  7. MHD models compared with Artemis observations at -60 Re

    NASA Astrophysics Data System (ADS)

    Gencturk Akay, Iklim; Sibeck, David; Angelopoulos, Vassilis; Kaymaz, Zerefsan; Kuznetsova, Maria

    2016-07-01

    The distant magnetotail has been one of the least studied magnetic regions of the Earth's magnetosphere compared to the other near Earth both dayside and nightside magnetospheric regions owing to the limited number of spacecraft observations. Since 2011, ARTEMIS spacecraft give an excellent opportunity to study the magnetotail at lunar distances in terms of data quality and parameter space. This also gives opportunities to improve the magnetotail models at -60 Re and encourages the modelling studies of the distant magnetotail. Using ARTEMIS data in distant magnetotail, we create magnetic field and plasma flow vector maps in different planes and separated with IMF orientation to understand the magnetotail dynamics at this distance. For this study, we use CCMC's Run-on-Request resources of the MHD models; specifically SWMF-BATS-R-US, OpenGGCM, and LFM and perform the similar analysis with the models. Our main purpose in this study is to measure the performance of the MHD models at -60 Re distant magnetotail by comparing the model results with Artemis observations. In the literature, such a comprehensive comparative study is lacking in the distant tail. Preliminary results show that in general all three models underestimate the magnetic field structure while overestimating the flow speed. In the cross-sectional view, LFM seems to produce the better agreement with the observations. A clear dipolar magnetic field structure is seen with dawn-dusk asymmetry in all models owing to slight positive IMF By but the effect was found to be exaggerated. All models show tailward flows at this distance of the magnetotail, most possibly owing to the magnetic reconnection at the near Earth tail distances. A detailed comparison of several tail characteristics from the models will be presented and discussions will be given with respect to the observations from Artemis at this distance.

  8. Satellite microwave observations of a storm complex: A comparative analysis

    NASA Technical Reports Server (NTRS)

    Martin, D. W.

    1985-01-01

    The hypothesis that cold events correspond to a particular stage in a class of thunderstorms was tested. That class is a storms class which updrafts are: (1) strong, broad and moist, and (2) extend well above the freezing level. Condition (1) implies strong mesoscale forcing. Condition (2) implies a tall updraft or a relatively low freezing level. Such storms should have big, intense radar echoes and cold, fast-growing anvils. The thunderstorm events were analyzed by radar, rain gauge and GOES infrared observations. Radar was the starting point for detection and definition of the hypothesized thunderstorms. The radar signature is compared to the signature of the storm in rain gauge observations, satellite infrared images and satellite microwave images.

  9. Halo Coronal Mass Ejections: Comparing Observations and Models

    NASA Technical Reports Server (NTRS)

    Gilbert, Holly; Orlove, Matthew; SaintCyr, O.; Mays, L.; Gopalswamy, N.

    2011-01-01

    Since 1996, the SOHO LASCO coronagraphs have detected "halo" CMEs that appear to be directed toward Earth, but information about the size and speed of these events seen face-on has been limited. From a single vantage point along the Sun-Earth line, the primary limitation has been ambiguity in fitting the cone model (or other forward-modeling techniques, e.g., Thernisian et al., 2006). But in the past few years, the STEREO mission has provided a view of Earth-directed events from the side. These events offer the opportunity to compare measurements (width and speed) of halo CMEs observed by STEREO with models that derive halo CME properties. We report here results of such a comparison on a large sample of LASCO CMEs in the STEREO era.

  10. Comparing soil moisture memory in satellite observations and models

    NASA Astrophysics Data System (ADS)

    Stacke, Tobias; Hagemann, Stefan; Loew, Alexander

    2013-04-01

    A major obstacle to a correct parametrization of soil processes in large scale global land surface models is the lack of long term soil moisture observations for large parts of the globe. Currently, a compilation of soil moisture data derived from a range of satellites is released by the ESA Climate Change Initiative (ECV_SM). Comprising the period from 1978 until 2010, it provides the opportunity to compute climatological relevant statistics on a quasi-global scale and to compare these to the output of climate models. Our study is focused on the investigation of soil moisture memory in satellite observations and models. As a proxy for memory we compute the autocorrelation length (ACL) of the available satellite data and the uppermost soil layer of the models. Additional to the ECV_SM data, AMSR-E soil moisture is used as observational estimate. Simulated soil moisture fields are taken from ERA-Interim reanalysis and generated with the land surface model JSBACH, which was driven with quasi-observational meteorological forcing data. The satellite data show ACLs between one week and one month for the greater part of the land surface while the models simulate a longer memory of up to two months. Some pattern are similar in models and observations, e.g. a longer memory in the Sahel Zone and the Arabian Peninsula, but the models are not able to reproduce regions with a very short ACL of just a few days. If the long term seasonality is subtracted from the data the memory is strongly shortened, indicating the importance of seasonal variations for the memory in most regions. Furthermore, we analyze the change of soil moisture memory in the different soil layers of the models to investigate to which extent the surface soil moisture includes information about the whole soil column. A first analysis reveals that the ACL is increasing for deeper layers. However, its increase is stronger in the soil moisture anomaly than in its absolute values and the first even exceeds the

  11. Comparative genomic hybridization analysis of newly established retinoblastoma cell lines of adherent growth compared with Y79 of nonadherent growth.

    PubMed

    Kim, Jeong Hun; Kim, Jin Hyoung; Yu, Young Suk; Kim, Dong Hun; Kim, Yong Kyu; Kim, Kyu-Won

    2008-08-01

    Retinoblastoma (RB) shows cytogenetic aberrations involving genes other than RB gene located on 13q14. We analyzed genomic aberration in newly established RB cell lines SNUOT-RB1 and SNUOT-RB4 of adherent growth and Y79 cell line of nonadherent growth by microarray comparative genomic hybridization. SNUOT-RB1 showed 44 significant copy number changes (gain in 11 and loss in 33, P<0.0005). SNUOT-RB4 showed 42 significant copy number changes (gain in 8 and loss in 34, P<0.0005). Y79 cell line had the greatest gain of 19.65-fold in the locus of MYCN gene 2p24.1, whereas SNUOT-RB1 and SNUOT-RB4 showed no significant gain. SNUOT-RB1 and SNUOT-RB4 gained chromosomal copy numbers commonly in chromosome 11, especially in locus 11q13, which is responsible for cancer-related genes such as CCND1, MEN1, and FGF3. Losses of copy numbers occurred in chromosomes 3, 9, 10, 11, 16, and 17. In summary, SNUOT-RB1 and SNUOT-RB4 represented similar pattern in gain and loss of chromosomal copy number changes, while different from Y79. The loss of CYLD gene of tumor suppressor gene, 16q12-q13, was only on locus of common involvement in 3 cell lines. PMID:18799932

  12. Aerosol observations and growth rates in the tropical tropopause layer

    NASA Astrophysics Data System (ADS)

    Waddicor, D. A.; Vaughan, G.; Choularton, T. W.; Bower, K. N.; Coe, H.; Gallagher, M.; Williams, P. I.; Flynn, M.; Volz-Thomas, A.; Pätz, W.; Isaac, P.; Hacker, J.; Arnold, F.; Schlager, H.; Whiteway, J. A.

    2012-01-01

    We present a case study of Aitken and accumulation mode aerosol observed downwind of the anvils of deep tropical thunderstorms. The measurements were made by condensation nuclei counters flown on the Egrett high-altitude aircraft from Darwin during the ACTIVE campaign, in monsoon conditions producing widespread convection over land and ocean. Maximum measured concentrations of aerosol in the size range 10-100 nm were 25 000 cm-3 STP. By calculating back-trajectories from the observations, and projecting on to infrared satellite images, the time since the air exited cloud was estimated. In this way a time scale of ~ 3-4 h was derived for the 10-100 nm aerosol concentration to reach its peak. We examine the hypothesis that the growth in aerosol concentrations can be explained by production of sulphuric acid from SO2 followed by particle nucleation and coagulation. Estimates of the sulphuric acid production rate show that the observations are only consistent with this hypothesis if the particles coagulate to sizes > 10 nm much more quickly than is suggested by current theory. Alternatively, other condensible gases (possibly organic) drive the growth of aerosol particles in the TTL.

  13. Comparing growth phenology of co-occurring deciduous and evergreen conifers exposed to drought

    PubMed Central

    Swidrak, Irene; Schuster, Roman; Oberhuber, Walter

    2013-01-01

    Plant phenological events are influenced by climate factors such as temperature and rainfall. To evaluate phenological responses to water availability in a Spring Heath-Pine wood (Erico-Pinetum typicum), the focus of this study was to determine intra-annual dynamics of apical and lateral growth of co-occurring early successional Larix decidua and Pinus sylvestris and late successional Picea abies exposed to drought. The effect of reduced plant water availability on growth phenology was investigated by conducting a rainfall exclusion experiment. Timing of key phenological dates (onset, maximum rate, end, duration) of growth processes were compared among species at the rain-sheltered and control plot during 2011 and 2012. Shoot and needle elongation were monitored on lateral branches in the canopy at c. 16 m height and radial growth was recorded by automatic dendrometers at c. 1.3 m height of > 120 yr old trees. Different sequences in aboveground growth phenology were detected among the three species under the same growing conditions. While onset of radial growth in April through early May was considerably preceded by onset of needle growth in Larix decidua (5 - 6 weeks) and shoot growth in Pinus sylvestris (c. 3 weeks), it occurred quite simultaneously with onset of shoot growth in Picea abies. Low water availability had a minor impact on onset of aboveground growth, which is related to utilization of stored water, but caused premature cessation of aboveground growth. At the control plot mean growing season length was 130 days in Pinus sylvestris, 95 days in Larix decidua and 73 days in Picea abies supporting the hypothesis that early successional species are resource expenders, while late successional species are more efficient in utilizing resources and develop safer life strategies. High synchronicity found in culmination of radial growth in late spring (mid-May through early June) prior to occurrence of more favourable environmental conditions in summer might

  14. Comparing growth phenology of co-occurring deciduous and evergreen conifers exposed to drought.

    PubMed

    Swidrak, Irene; Schuster, Roman; Oberhuber, Walter

    2013-12-01

    Plant phenological events are influenced by climate factors such as temperature and rainfall. To evaluate phenological responses to water availability in a Spring Heath-Pine wood (Erico-Pinetum typicum), the focus of this study was to determine intra-annual dynamics of apical and lateral growth of co-occurring early successional Larix decidua and Pinus sylvestris and late successional Picea abies exposed to drought. The effect of reduced plant water availability on growth phenology was investigated by conducting a rainfall exclusion experiment. Timing of key phenological dates (onset, maximum rate, end, duration) of growth processes were compared among species at the rain-sheltered and control plot during 2011 and 2012. Shoot and needle elongation were monitored on lateral branches in the canopy at c. 16 m height and radial growth was recorded by automatic dendrometers at c. 1.3 m height of > 120 yr old trees. Different sequences in aboveground growth phenology were detected among the three species under the same growing conditions. While onset of radial growth in April through early May was considerably preceded by onset of needle growth in Larix decidua (5 - 6 weeks) and shoot growth in Pinus sylvestris (c. 3 weeks), it occurred quite simultaneously with onset of shoot growth in Picea abies. Low water availability had a minor impact on onset of aboveground growth, which is related to utilization of stored water, but caused premature cessation of aboveground growth. At the control plot mean growing season length was 130 days in Pinus sylvestris, 95 days in Larix decidua and 73 days in Picea abies supporting the hypothesis that early successional species are resource expenders, while late successional species are more efficient in utilizing resources and develop safer life strategies. High synchronicity found in culmination of radial growth in late spring (mid-May through early June) prior to occurrence of more favourable environmental conditions in summer might

  15. Cosmological observables, infrared growth of fluctuations, and scale-dependent anisotropies

    NASA Astrophysics Data System (ADS)

    Giddings, Steven B.; Sloth, Martin S.

    2011-09-01

    We simplify and extend semiclassical methods in inflationary cosmology that capture leading IR corrections to correlators. Such IR effects can be absorbed into a coordinate change when examining sufficiently local observables, but not when comparing observations at large separation in scales, such as seen by a late-time observer. The analysis is facilitated by definition of a scale-dependent metric and physical momentum. These assist definition of “IR-safe” observables seen by a postinflationary observer, which are contrasted to those based on the local geometry of the reheating surface. For the former observables, the observer’s horizon provides an effective IR cutoff. IR growth of fluctuations contributes to enhanced statistical inhomogeneities/anisotropies at short scales, observation of which by a present-day observer might be sought in 21 cm measurements. Such IR corrections are argued to become large for a very late-time observer.

  16. Comparative observations on inorganic and organic lead neurotoxicity

    SciTech Connect

    Verity, M.A. )

    1990-11-01

    Environmental and occupational exposure to lead still generates concern, and recent studies have focused such concern on the role of body burden of lead during the fetal/neonatal period, especially in the genesis of disturbed central nervous system development. This discussion provides some comparative observations on the neurotoxicity of inorganic and organic lead species. The characteristic acute, predominantly cerebellar encephalopathy associated with neonatal high lead exposure contrasts to the subtle, axo-dendritic disorganization shown to be associated with low-level neonatal inorganic Pb{sup 2+} exposure. There is a preferential involvement of the hippocampus in both low-level inorganic Pb{sup 2+} and organolead exposure, and the clinical syndromes of irritability, hyperactivity, aggression, and seizures are common features of disturbed hippocampal function. Neurotransmitter system abnormalities have been described with inorganic Pb{sup 2+}, but recent attention has focused on the abnormalities in glutamate, dopamine, and/or {gamma}-aminobutyric acid (GABA) uptake, efflux, and metabolism. Abnormalities of GABA and glutamate metabolism are also found with the organolead species. Testable hypotheses are presented that may provide an understanding of the pathogenesis underlying dystrophic neuronal development under the influence of inorganic or organolead intoxication.

  17. Direct observation of epitaxial organic film growth: temperature-dependent growth mechanisms and metastability.

    PubMed

    Marchetto, Helder; Schmidt, Thomas; Groh, Ullrich; Maier, Florian C; Lévesque, Pierre L; Fink, Rainer H; Freund, Hans-Joachim; Umbach, Eberhard

    2015-11-21

    The growth of the first ten layers of organic thin films on a smooth metallic substrate has been investigated in real-time using the model system PTCDA on Ag(111). The complex behaviour is comprehensively studied by electron microscopy, spectroscopy and diffraction in a combined PEEM/LEEM instrument revealing several new phenomena and yielding a consistent picture of this layer growth. PTCDA grows above room temperature in a Stranski-Krastanov mode, forming three-dimensional islands on a stable bi-layer, in competition with metastable 3rd and 4th layers. Around room temperature this growth mode changes into a quasi layer-by-layer growth, while at temperatures below about 250 K a Vollmer-Weber-like behaviour is observed. By means of laterally resolved soft X-ray absorption spectroscopy the orientation of all adsorbed molecules is found to be homogeneously flat lying on the surface, even during the growth process. The films grow epitaxially, showing long-range order with rotational domains. For the monolayer these domains could be directly analysed, showing an average size of several micrometers extending over substrate steps. PMID:26462749

  18. Comparing apples with apples: it is time for standardized reporting of neonatal nutrition and growth studies.

    PubMed

    Cormack, Barbara E; Embleton, Nicholas D; van Goudoever, Johannes B; Hay, William W; Bloomfield, Frank H

    2016-06-01

    The ultimate goal of neonatal nutrition care is optimal growth, neurodevelopment, and long-term health for preterm babies. International consensus is that increased energy and protein intakes in the neonatal period improve growth and neurodevelopment, but after more than 100 y of research the optimum intakes of energy and protein remain unknown. We suggest an important factor contributing to the lack of progress is the lack of a standardized approach to reporting nutritional intake data and growth in the neonatal literature. We reviewed randomized controlled trials and observational studies documented in MEDLINE and the Web of Science from 2008 to 2015 that compared approximately 3 vs. 4 g.kg(-1).d(-1) protein for preterm babies in the first month after birth. Consistency might be expected in the calculation of nutritional intake and assessment of growth outcomes in this relatively narrow scope of neonatal nutrition research. Twenty-two studies were reviewed. There was substantial variation in methods used to estimate and calculate nutritional intakes and in the approaches used in reporting these intakes and measures of infant growth. Such variability makes comparisons amongst studies difficult and meta-analysis unreliable. We propose the StRONNG Checklist-Standardized Reporting Of Neonatal Nutrition and Growth to address these issues. PMID:26866908

  19. Gulf Stream Meanders: Observations on Propagation and Growth

    NASA Astrophysics Data System (ADS)

    Watts, D. Randolph; Johns, William E.

    1982-11-01

    We present a new method for continuously tracking the location of the Gulf Stream using a moored array of inverted echo sounders. Time series of lateral displacements of the front, shown accurate to ± 8 km, have been collected along three sections spaced 100, 150, and 200 km downstream (NE) of Cape Hatteras, North Carolina, for a period of 12 months. These records are highly coherent at all periodicities longer than 4 days. From the observed phase lags, a dispersion relationship is presented for the meanders: As the period and wavelength (T, λ) increase from (4 days, 180 km) to (30 days, 600 km), the phase speed decreases smoothly from 40 to 20 km d-1. The meanders exhibited rapid growth at periods longer than 4 days, doubling in variance in each 50-km step downstream. This downstream growth is most appropriately described by a spatial e-folding scale κ-1 ˜400 km for (T, λ) ≲ (9 days, 300 km), and a temporal e-folding scale σ-1 ˜ 6 days for (T, λ) ≳ (14 days, 400 km).

  20. Observation of number-density-dependent growth of plasmonic nanobubbles.

    PubMed

    Nakajima, Takashi; Wang, Xiaolong; Chatterjee, Souvik; Sakka, Tetsuo

    2016-01-01

    Interaction dynamics of laser pulses and nanoparticles are of great interest in recent years. In many cases, laser-nanoparticle interactions result in the formation of plasmonic nanobubbles, and the dynamics of nanoparticles and nanobubbles are inseparable. So far, very little attention has been paid to the number density. Here we report the first observation of number-density-dependent growth of plasmonic nanobubbles. Our results show that the nanobubbles growth depends (does not depend) on the number density at high (low) laser fluence, although the inter-particle distance in the solution is as long as 14-30 μm. This cannot be explained by the existing physical picture, and we propose a new model which takes into account the pressure waves arising from nanoparticles. The numerical results based on this model agree well with the experimental results. Our findings imply that the number density can be a new doorknob to control laser-nanobubble as well as laser-nanoparticle interactions. PMID:27354184

  1. Observation of number-density-dependent growth of plasmonic nanobubbles

    PubMed Central

    Nakajima, Takashi; Wang, Xiaolong; Chatterjee, Souvik; Sakka, Tetsuo

    2016-01-01

    Interaction dynamics of laser pulses and nanoparticles are of great interest in recent years. In many cases, laser-nanoparticle interactions result in the formation of plasmonic nanobubbles, and the dynamics of nanoparticles and nanobubbles are inseparable. So far, very little attention has been paid to the number density. Here we report the first observation of number-density-dependent growth of plasmonic nanobubbles. Our results show that the nanobubbles growth depends (does not depend) on the number density at high (low) laser fluence, although the inter-particle distance in the solution is as long as 14–30 μm. This cannot be explained by the existing physical picture, and we propose a new model which takes into account the pressure waves arising from nanoparticles. The numerical results based on this model agree well with the experimental results. Our findings imply that the number density can be a new doorknob to control laser-nanobubble as well as laser-nanoparticle interactions. PMID:27354184

  2. Fish plasma lipoproteins--comparative observations in serranides and sparides.

    PubMed

    Santulli, A; Cusenza, L; Modica, A; Curatolo, A; D'Amelio, V

    1991-01-01

    1. Diet, time from last feeding, temperature, season and sexual stage are some of the factors influencing the lipoprotein pattern. 2. Keeping these factors constant species-specific differences observed among lipoprotein patterns of Sparus aurata, Puntazzo puntazzo, Diplodus sargus, Diplodus vulgaris and Dicentrarchus labrax are discussed. 3. Feeding habits and therefore lipid absorption and the rate of lipoprotein maturation process are the factors determining the observed differences. PMID:1764905

  3. Comparative growth and development of hexaploid and tetraploid reed canarygrass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Reed canarygrass (Phalaris arundinacea L.) is a globally distributed forage species, a potential biofuel, and an important invasive weed. At more northern latitudes in exists as a tetraploid and at equatorial to mid-latitudes as a hexaploid, especially in Mediterranean climates. Growth and developme...

  4. Comparing ionospheric models with mid-latitude ionosonde observations

    NASA Astrophysics Data System (ADS)

    Al-Ubaidi, Najat M. R.

    2009-06-01

    The purpose of this research work is to validate the ionospheric models (IRI and CHIU) to assess its suitability and usefulness as an operational tool. The ionospheric model is a computer model designed to predict the state of the global ionosphere for 24 h. The scope was limited to conduct comparisons between the predicted F2 layer critical frequencies (f0F2) against observed ionosonde data. The ionospheric prediction model (IPM) was designed to predict by using monthly median sunspot number, while the observation data are taken from two digital ionospheric sounding stations (Okinawa, 26.28N, 127.8E and Wakkanai, 45.38N, 141.66E) which lies within the mid-latitude region of the globe. Analysis of the f0F2 data from stations for year (2001) with high solar activity and year (2004) with low solar activity, four months (March, June, September and December) chosen based primarily on data availability. From results it seen that the ratio between monthly median predicted and observed f0F2 values for each model used in this research work and for the chosen months was nonlinear with local time, so the empirical formula for applying correction factors were determined, these formula can be used to correct the error occurred in predicted f0F2 value.

  5. Direct observation of interface instability during crystal growth

    NASA Technical Reports Server (NTRS)

    Tiller, W. A.; Feigelson, R. S.; Elwell, D.

    1982-01-01

    The general aim of this investigation was to study interface stability and solute segregation phenomena during crystallization of a model system. Emphasis was to be placed on direct observational studies partly because this offered the possibility at a later stage of performing related experiments under substantially convection-free conditions in the space shuttle. The major achievements described in this report are: (1) the development of a new model system for fundamental studies of crystal growth from the melt and the measurement of a range of material parameters necessary for comparison of experiment with theory. (2) The introduction of a new method of measuring segregation coefficient using absorption of a laser beam by the liquid phase. (3) The comparison of segregation in crystals grown by gradient freezing and by pulling from the melt. (4) The introduction into the theory of solute segregation of an interface field term and comparison with experiment. (5) The introduction of the interface field term into the theories of constitutional supercooling and morphological stability and assessment of its importance.

  6. Observations on the Growth of Roughness Elements Into Icing Feathers

    NASA Technical Reports Server (NTRS)

    Vargas, Mario; Tsao, Jen, Ching

    2007-01-01

    This work presents the results of an experiment conducted in the Icing Research Tunnel at NASA Glenn Research Center to understand the process by which icing feathers are formed in the initial stages of ice accretion formation on swept wings. Close-up photographic data were taken on an aluminum NACA 0012 swept wing tip airfoil. Two types of photographic data were obtained: time sequence close-up photographic data during the run and close-up photographic data of the ice accretion at the end of each run. Icing runs were conducted for short ice accretion times from 10 to 180 sec. The time sequence close-up photographic data was used to study the process frame by frame and to create movies of how the process developed. The movies confirmed that at glaze icing conditions in the attachment line area icing feathers develop from roughness elements. The close-up photographic data at the end of each run showed that roughness elements change into a pointed shape with an upstream facet and join on the side with other elements having the same change to form ridges with pointed shape and upstream facet. The ridges develop into feathers when the upstream facet grows away to form the stem of the feather. The ridges and their growth into feathers were observed to form the initial scallop tips present in complete scallops.

  7. Comparative analyses of observations of lunar transient phenomena.

    NASA Technical Reports Server (NTRS)

    Cameron, W. S.

    1972-01-01

    From the author's collection of more than 900 reports of lunar transient phenomena (LTP) covering the period 1540-1970, 771 positive plus 112 negative observations (several times more than any previously published analyses) with sufficient ancillary data were analyzed for five hypotheses of causes. Treated as two groups they were divided into four categories (gaseous, reddish, bluish, and brightenings) and were analyzed separately and combined with respect to the hypotheses. The five hypotheses involved effects of tides, sunrise, low-angle illumination, earth's magnetic tail, and solar particles.

  8. Direct observation of mammalian cell growth and size regulation

    PubMed Central

    Son, Sungmin; Tzur, Amit; Weng, Yaochung; Jorgensen, Paul; Kim, Jisoo; Kirschner, Marc W.; Manalis, Scott R.

    2012-01-01

    We introduce a microfluidic system for simultaneously measuring single cell mass and cell cycle progression over multiple generations. We use this system to obtain over 1,000 hours of growth data from mouse lymphoblast and pro-B-cell lymphoid cell lines. Cell lineage analysis revealed a decrease in the growth rate variability at the G1/S phase transition, which suggests the presence of a growth rate threshold for maintaining size homeostasis. PMID:22863882

  9. Comparing Observed Hurricane Conditions Against Potential Future Climate Change Influences

    NASA Astrophysics Data System (ADS)

    Graham, W. D.

    2012-12-01

    Climate Adaptation Science Investigators: (CASI) is to advance and apply NASA's scientific expertise and products to develop climate adaptation strategies that support NASA's overall mission by minimizing risks to each center's operations, physical assets, and personnel. Using Hurricane Katrina observations as a baseline, we use ADCIRC to model surge extent with simple modifications of the storm track. We examine two time now (T0) scenarios of present-day climatological factors: 1) translating the 2005 path 7 km west; and 2) rotating the approach angle from due-north to WNW. Second, we examine two future time scenarios (TX) by infusing climate change conditions, such as sea level rise and increased storm intensity, into a T0 baseline to assess future impacts. The primary goal of this work entails planning and protecting NASA assets and infrastructure. The adjacent communities, state and local emergency managers, gain benefit from this NASA work as data and analysis includes the surrounding geography.

  10. Comparing climate projections to observations up to 2011

    NASA Astrophysics Data System (ADS)

    Rahmstorf, Stefan; Foster, Grant; Cazenave, Anny

    2012-12-01

    We analyse global temperature and sea-level data for the past few decades and compare them to projections published in the third and fourth assessment reports of the Intergovernmental Panel on Climate Change (IPCC). The results show that global temperature continues to increase in good agreement with the best estimates of the IPCC, especially if we account for the effects of short-term variability due to the El Niño/Southern Oscillation, volcanic activity and solar variability. The rate of sea-level rise of the past few decades, on the other hand, is greater than projected by the IPCC models. This suggests that IPCC sea-level projections for the future may also be biased low.

  11. Comparative observations on the tooth root morphology of Gigantopithecus blacki.

    PubMed

    Kupczik, Kornelius; Dean, M Christopher

    2008-02-01

    The extinct great ape Gigantopithecus blacki from the middle Pleistocene of China and Vietnam is known only from dental and mandibular remains, and its dietary specializations remain contentious. Here, for the first time, we describe the root morphology in G. blacki using computed tomography and three-dimensional image processing. We quantify the tooth root lengths and surface areas of the female G. blacki mandible No. 1 from the Liucheng Cave and compare it to a sample of extant great apes and humans, as well as the giant panda (Ailuropoda melanoleuca) and the American black bear (Ursus americanus). The results show that, in G. blacki, the pattern of mandibular root numbers-particularly that of the premolars-corresponds with that of Gorilla gorilla, Pan troglodytes, and Pongo pygmaeus. However, G. blacki can be distinguished from the extant hominids by having relatively higher values for postcanine root length and surface area, both absolutely and relative to mandibular size (except for premolar root lengths of humans). The relatively large postcanine root surface areas, which are most similar to A. melanoleuca, suggest that the dentition of G. blacki was adapted to sustaining relatively large occlusal forces needed to fracture mechanically resistant foods such as bamboo. PMID:18045651

  12. Using AGN to Observe the Growth of the Cosmic Web

    NASA Astrophysics Data System (ADS)

    Murray, S.; Jones, C.; Forman, W.; Kenter, A.; Vihklinin, A.; Markevitch, M.; Brand, K.; Jannuzi, B.; Kochanek, C.; Eisenstein, D.

    We present X-ray and optical observations of the contiguous 9 3 sq deg XBootes survey made with the ACIS instrument on Chandra The X-ray survey consists of 126 5ksec pointings that achieve a sensitivity of about 4 times10 -15 erg cm -2 s -1 in the 0 5--7 keV band At this sensitivity limit we detect 4642 X-ray sources As part of the AGES galaxy survey in the Bootes region Kochanek et al 2005 we have obtained 1800 redshifts of the X-ray selected objects most of which are AGN yielding a density of sim150 AGN per square degree The mean AGN redshift is 1 3 with the distribution extending to z 4 We have analyzed the spatial distribution of the X-ray selected AGN and compared this to the distribution of the sim20000 AGES galaxies To z sim0 7 the limit of galaxy sample the galaxies and AGN both trace the same structures and show the same web of voids and filaments At larger redshifts the X-ray AGN continue to show the characteristic structure of voids and filaments Quantitatively we computed the spatial 2-point correlation function for the X-ray selected AGN and find that the correlation length r 0 simeq6 4 h -1 Mpc and the exponent gamma simeq-1 7 of the correlation function are similar to the canonical values derived for galaxies In addition we have compared the correlation function in several redshift intervals and find that the correlation length is approximately constant to z sim1 5

  13. A facile method to observe graphene growth on copper foil

    NASA Astrophysics Data System (ADS)

    Yang, Fan; Liu, Yangqiao; Wu, Wei; Chen, Wei; Gao, Lian; Sun, Jing

    2012-11-01

    A novel scanning electron microscope (SEM) method is presented for high contrast identification of each layer of pyramidal graphene domains grown on copper. We obtained SEM images by combining the advantages of the high resolution property of the secondary electron signal and the elemental sensitivity of the backscattering electron signal. Through this method, we investigated the difference in the growth mechanisms of mono-layer and few-layer graphene. Due to different lattice mismatches, both the surface adsorption process and the epitaxial growth process existed under the atmospheric growth conditions. Moreover, the copper oxidation process can be easily discovered. It is obvious from the SEM images that the graphene greatly delayed the oxidation process of the copper surface. Finally, the nucleation and growth speed of graphene domains was found to depend on the linear array distribution of surface ledges and terraces of annealed rolled copper foil. This result explains the linear rows of graphene during the growth process and accords with theoretical results.

  14. Addressing Informatics Barriers to Conducting Observational Comparative Effectiveness Research: A Comparative Case Analysis

    ERIC Educational Resources Information Center

    Boone, Christopher P. D.

    2013-01-01

    Background: The U.S. health care system has been under immense scrutiny for ever-increasing costs and poor health outcomes for its patients. Comparative Effectiveness Research (CER) has emerged as a generally accepted practice by providers, policy makers, and scientists as an approach to identify the most clinical- and cost-effective interventions…

  15. Comparing cellular performance of Yarrowia lipolytica during growth on glucose and glycerol in submerged cultivations

    PubMed Central

    2013-01-01

    Yarrowia lipolytica is an attractive host for sustainable bioprocesses due to its ability to utilize a variety of carbon substrates and convert them to a range of different product types (including lipids, organic acids and polyols) under specific conditions. Despite an increasing number of applications for this yeast, relatively few studies have focused on uptake and metabolism of carbon sources, and the metabolic basis for carbon flow to the different products. The focus of this work was quantification of the cellular performance of Y. lipolytica during growth on glycerol, glucose or a mixture of the two. Carbon substrate uptake rate, growth rate, oxygen utilisation (requirement and uptake rate) and polyol yields were estimated in batch cultivations at 1 litre scale. When glucose was used as the sole carbon and energy source, the growth rate was 0.24 h-1 and biomass and CO2 were the only products. Growth on glycerol proceeded at approximately 0.30 h-1, and the substrate uptake rate was 0.02 mol L-1 h-1 regardless of the starting glycerol concentration (10, 20 or 45 g L-1). Utilisation of glycerol was accompanied by higher oxygen uptake rates compared to glucose growth, indicating import of glycerol occurred initially via phosphorylation of glycerol into glycerol-3-phosphate. Based on these results it could be speculated that once oxygen limitation was reached, additional production of NADH created imbalance in the cofactor pools and the polyol formation observed could be a result of cofactor recycling to restore the balance in metabolism. PMID:24088397

  16. An observational study regarding the rate of growth in vertical and radial growth phase superficial spreading melanomas

    PubMed Central

    Betti, Roberto; Agape, Elena; Vergani, Raffaella; Moneghini, Laura; Cerri, Amilcare

    2016-01-01

    The natural history of superficial spreading melanomas (SSMs) involves the progression from a radial growth phase (RGP) to a vertical growth phase (VGP). Currently, a patient's history represents the only method to estimate the rate of tumor growth. The present study aimed to verify whether the estimated rate of growth (ROG) of SSMs with a RGP or VGP exhibited any differences, and to evaluate the possible implications for the most important prognostic determinants. ROG was quantified as the ratio between Breslow's thickness in millimeters (mm) and the time of tumor growth in months, defined as the time between the date that the patient had first noticed the lesion in which melanoma subsequently developed and the date on which the patient first felt this lesion changed. A total of 105 patients (58 male and 47 female) were studied. Of these, 66 had VGP-SSMs, whilst 39 had RGP-only SSMs (RGP-SSMs). No significant differences in age and gender were observed between these groups. The mean Breslow's thickness in patients with VGP-SSMs was significantly greater than in patients with RGP-SSMs (0.78±0.68 vs. 0.48±0.22 mm, P=0.0096). Similarly, the ROG was observed to be higher in VGP-SSM vs. RGP-SSM patients (0.13±0.16 vs. 0.065±0.09 mm/month, P=0.0244). In patients with VGP-SSMs, Breslow's thickness and ROG were significantly higher for tumors with a mitotic rate of ≥1 mitosis/mm2 compared with those with <1 mitosis/mm2 (1.15±0.96 vs. 0.56±0.30 mm, P=0.0005; and 0.188±0.20 vs. 0.09±0.12 mm/month, P=0.0228, respectively). According to these results, two subsets of SSMs exist: The first is characterized by the presence of mitosis and a higher ROG, while the second exhibits a more indolent behavior and is characterized by an RGP only. Given the differences in the Breslow's thickness and ROG, clinicians must be aware of the possible diagnostic delay in these subsets of melanoma that, differently from true nodular melanomas, generally fulfill the classical ABCD

  17. Fault growth by linkage: observations and implications from analogue models

    NASA Astrophysics Data System (ADS)

    Mansfield, Chris; Cartwright, Joe

    2001-05-01

    Using time sequence analyses of extensional fault models we demonstrate the pivotal role played by fault segmentation in the accumulation of displacement and length during the growth of faults. Experiments are described in which incremental steps during the development of individual faults have been reconstructed from time-lapse photographs taken during model deformation. These records confirm the composite segment hierarchy of fault structure, a pattern that is frequently recognised in many natural arrays. They reveal the progressive enlargement of individual faults to be the product of a repetitive cycle of tip-line propagation, overlap and linkage between nearest neighbours. By contrasting the displacement patterns of successive increments during growth convincing evidence is also presented to suggest that individual segments of faults may remain kinematically independent once they are physically linked. This behaviour is shown to be responsible for the characteristic saw-tooth patterns often recognised in strike-parallel fault displacement profiles. Such patterns are believed to arise where relict segment boundaries remain preserved as asperities to slip, so that displacement is confined to discrete parts of a fault plane surface. Growth in this way also causes the maximum displacement (D) and surface length (L) of faults to continually change by different proportions. Incremental displacement records presented here corroborate field evidence which shows that linkage between fault segments during growth is responsible for a significant component of the spread of values often recorded in D versus L compilations. Finally, we speculate that linkage between fault segments also accounts for transient irregularities recorded in the frequency distribution of the fault length populations of each model.

  18. COMPARATIVE KINETIC STUDIES OF NITRATE-LIMITED GROWTH AND NITRATE UPTAKE IN PHYTOPLANKTON IN CONTINUOUS CULTURE

    EPA Science Inventory

    A comparative kinetic study of nitrate-limited growth and nitrate uptake was carried out in chemostat cultures of Ankistrodesmus falcatus, Asterionella formosa, Fragilaria crotonensis. In each species growth rate (microgram) was related to total cell nitrogen or cell quota (q) by...

  19. ULF foreshock under radial IMF: THEMIS observations and global kinetic simulation Vlasiator results compared

    NASA Astrophysics Data System (ADS)

    Palmroth, M.; Archer, M.; Vainio, R.; Hietala, H.; Pfau-Kempf, Y.; Hoilijoki, S.; Hannuksela, O.; Ganse, U.; Sandroos, A.; Alfthan, S. von; Eastwood, J. P.

    2015-10-01

    For decades, monochromatic large-scale ultralow frequency (ULF) waves with a period of about 30 s have been observed upstream of the quasi-parallel bow shock. These waves typically propagate obliquely with respect to the interplanetary magnetic field (IMF), while the growth rate for the instability causing the waves is maximized parallel to the magnetic field. It has been suggested that the mechanism for the oblique propagation concerns wave refraction due to the spatial variability of the suprathermal ions, originating from the E × B drift component. We investigate the ULF foreshock under a quasi-radial IMF with Vlasiator, which is a newly developed global hybrid-Vlasov simulation solving the Vlasov equation for protons, while electrons are treated as a charge-neutralizing fluid. We observe the generation of the 30 s ULF waves and compare their properties to previous literature and multipoint Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft observations. We find that Vlasiator reproduces the foreshock ULF waves in all reported observational aspects. We conclude that the variability of the density and velocity of the reflected back streaming ions determines the large-scale structure of the foreshock, which affects the wave frequency, wavelength, and oblique propagation. We conclude that the wave refraction may also be at work for radial IMF conditions, which has earlier been thought of as an exception to the refraction mechanism due to the small E × B drift component. We suggest that additional refraction may be caused by the large-scale spatial variability of the density and velocity of the back streaming ions.

  20. Laboratory observation of magnetic field growth driven by shear flow

    SciTech Connect

    Intrator, T. P. Feng, Y.; Sears, J.; Weber, T.; Dorf, L.; Sun, X.

    2014-04-15

    Two magnetic flux ropes that collide and bounce have been characterized in the laboratory. We find screw pinch profiles that include ion flow v{sub i}, magnetic field B, current density J, and plasma pressure. The electron flow v{sub e} can be inferred, allowing the evaluation of the Hall J×B term in a two fluid magnetohydrodynamic Ohm's Law. Flux ropes that are initially cylindrical are mutually attracted and compress each other, which distorts the cylindrical symmetry. Magnetic field is created via the ∇×v{sub e}×B induction term in Ohm's Law where in-plane (perpendicular) shear of parallel flow (along the flux rope) is the dominant feature, along with some dissipation and magnetic reconnection. We predict and measure the growth of a quadrupole out-of-plane magnetic field δB{sub z}. This is a simple and coherent example of a shear flow driven dynamo. There is some similarity with two dimensional reconnection scenarios, which induce a current sheet and thus out-of-plane flow in the third dimension, despite the customary picture that considers flows only in the reconnection plane. These data illustrate a general and deterministic mechanism for large scale sheared flows to acquire smaller scale magnetic features, disordered structure, and possibly turbulence.

  1. Expansion and growth of structure observables in a macroscopic gravity averaged universe

    NASA Astrophysics Data System (ADS)

    Wijenayake, Tharake; Ishak, Mustapha

    2015-03-01

    We investigate the effect of averaging inhomogeneities on expansion and large-scale structure growth observables using the exact and covariant framework of macroscopic gravity (MG). It is well known that applying the Einstein's equations and spatial averaging do not commute and lead to the averaging problem and backreaction terms. For the MG formalism applied to the Friedman-Lemaitre-Robertson-Walker (FLRW) metric, the extra term can be encapsulated as an averaging density parameter denoted ΩA . An exact isotropic cosmological solution of MG for the flat FLRW metric is already known in the literature; we derive here an anisotropic exact solution. Using the isotropic solution, we compare the expansion history to current available data of distances to supernovae, baryon acoustic oscillations, cosmic microwave background last scattering surface data, and Hubble constant measurements, and find -0.05 ≤ΩA≤0.07 (at the 95% confidence level). For the flat metric case this reduces to -0.03 ≤ΩA≤0.05 . The positive part of the intervals can be rejected if a mathematical (and physical) prior is taken into account. We also find that the inclusion of this term in the fits can shift the values of the usual cosmological parameters by a few to several percents. Next, we derive an equation for the growth rate of large-scale structure in MG that includes a term due to the averaging and assess its effect on the evolution of the growth compared to that of the Lambda cold dark matter (Λ CDM ) concordance model. We find that an ΩA term of an amplitude range of [-0.04 ,-0.02 ] lead to a relative deviation of the growth from that of the Λ CDM of up to 2%-4% at late times. Thus, the shift in the growth could be of comparable amplitude to that caused by similar changes in cosmological parameters like the dark energy density parameter or its equation of state. The effect could also be comparable in amplitude to some systematic effects considered for future surveys. This

  2. Analysis of the growth process of gold nanorods with time-resolved observation.

    PubMed

    Takenaka, Yoshiko; Kitahata, Hiroyuki

    2009-08-01

    Gold nanorods are generated spontaneously in a surfactant solution. We developed an experimental setup where the growth of gold nanorods can be completely stopped at any instant. With this method, a time series of the growth process of gold nanorods was determined by the direct observation of nanorods with transmission electron microscopy. We estimated the growth rate of nanorods from the change in the average long-axis length over time. To understand the experimental results, we developed a mathematical model for the growth of nanorods. The present results should help to clarify the mechanism of the growth of gold nanorods. PMID:19792064

  3. Analysis of the growth process of gold nanorods with time-resolved observation

    NASA Astrophysics Data System (ADS)

    Takenaka, Yoshiko; Kitahata, Hiroyuki

    2009-08-01

    Gold nanorods are generated spontaneously in a surfactant solution. We developed an experimental setup where the growth of gold nanorods can be completely stopped at any instant. With this method, a time series of the growth process of gold nanorods was determined by the direct observation of nanorods with transmission electron microscopy. We estimated the growth rate of nanorods from the change in the average long-axis length over time. To understand the experimental results, we developed a mathematical model for the growth of nanorods. The present results should help to clarify the mechanism of the growth of gold nanorods.

  4. Remote automated multi-generational growth and observation of an animal in low Earth orbit.

    PubMed

    Oczypok, Elizabeth A; Etheridge, Timothy; Freeman, Jacob; Stodieck, Louis; Johnsen, Robert; Baillie, David; Szewczyk, Nathaniel J

    2012-03-01

    The ultimate survival of humanity is dependent upon colonization of other planetary bodies. Key challenges to such habitation are (patho)physiologic changes induced by known, and unknown, factors associated with long-duration and distance space exploration. However, we currently lack biological models for detecting and studying these changes. Here, we use a remote automated culture system to successfully grow an animal in low Earth orbit for six months. Our observations, over 12 generations, demonstrate that the multi-cellular soil worm Caenorhabditis elegans develops from egg to adulthood and produces progeny with identical timings in space as on the Earth. Additionally, these animals display normal rates of movement when fully fed, comparable declines in movement when starved, and appropriate growth arrest upon starvation and recovery upon re-feeding. These observations establish C. elegans as a biological model that can be used to detect changes in animal growth, development, reproduction and behaviour in response to environmental conditions during long-duration spaceflight. This experimental system is ready to be incorporated on future, unmanned interplanetary missions and could be used to study cost-effectively the effects of such missions on these biological processes and the efficacy of new life support systems and radiation shielding technologies. PMID:22130552

  5. Remote automated multi-generational growth and observation of an animal in low Earth orbit

    PubMed Central

    Oczypok, Elizabeth A.; Etheridge, Timothy; Freeman, Jacob; Stodieck, Louis; Johnsen, Robert; Baillie, David; Szewczyk, Nathaniel J.

    2012-01-01

    The ultimate survival of humanity is dependent upon colonization of other planetary bodies. Key challenges to such habitation are (patho)physiologic changes induced by known, and unknown, factors associated with long-duration and distance space exploration. However, we currently lack biological models for detecting and studying these changes. Here, we use a remote automated culture system to successfully grow an animal in low Earth orbit for six months. Our observations, over 12 generations, demonstrate that the multi-cellular soil worm Caenorhabditis elegans develops from egg to adulthood and produces progeny with identical timings in space as on the Earth. Additionally, these animals display normal rates of movement when fully fed, comparable declines in movement when starved, and appropriate growth arrest upon starvation and recovery upon re-feeding. These observations establish C. elegans as a biological model that can be used to detect changes in animal growth, development, reproduction and behaviour in response to environmental conditions during long-duration spaceflight. This experimental system is ready to be incorporated on future, unmanned interplanetary missions and could be used to study cost-effectively the effects of such missions on these biological processes and the efficacy of new life support systems and radiation shielding technologies. PMID:22130552

  6. Review of growth plate closure compared with age at sexual maturity and lifespan in laboratory animals.

    PubMed

    Kilborn, Susan H; Trudel, Guy; Uhthoff, Hans

    2002-09-01

    Although it is assumed that most mammals experience growth plate closure and cessation of bone growth soon after sexual maturity, bone growth in rats continues throughout their lifespan. The rat was compared to other laboratory animals to assess differences in the duration of bone growth and its relationship to age at sexual maturity and lifespan. We reviewed the literature from 1966 to March 1999 by searching MEDLINE and other databases. Growth closure times and age at sexual maturity were retrieved for the mouse, rabbit, dog, cat, sheep, cow, horse, nonhuman primates, and human. For all species, we calculated the ratios of: 1) age at growth plate closure to lifespan, 2) age at growth plate closure to age at sexual maturity, and 3) age at sexual maturity to average lifespan. The ratio of age at physis closure to the average lifespan was large for the rat (22 to 35) and showed some overlap with that of humans (17 to 25); this ratio was comparatively small in all other nonhuman species (range, 4 to 17). This finding indicates that bone growth continues in the rat for a greater proportion of their lifespan than does that in other species. The ratio of age at physis closure to age at sexual maturity was larger for the rat (5 to 6) than that for other species, indicating that bone growth continues much longer after sexual maturity in rats than in other animals. The ratio of age at sexual maturity to average lifespan was largest for humans and nonhuman primates (13 to 14), indicating the increased time to reach puberty versus that in other species. These differences are important for studies in which animal models are used in research involving bone growth. PMID:12213043

  7. Comparative growth of spotted fever group Rickettsia spp. strains in Vero cells

    PubMed Central

    Silva, Arannadia Barbosa; Duarte, Myrian Morato; Vizzoni, Vinicius Figueiredo; Duré, Ana Íris de Lima; Lopéz, Diego Montenegro; Nogueira, Rita de Maria Seabra; Soares, Carlos Augusto Gomes; Machado-Ferreira, Erik; Gazêta, Gilberto Salles

    2016-01-01

    In Brazil, the spotted fever group (SFG) Rickettsia rickettsii and Rickettsia parkeri related species are the etiological agents of spotted fever rickettsiosis. However, the SFG, Rickettsia rhipicephali, that infects humans, has never been reported. The study of growth dynamics can be useful for understanding the infective and invasive capacity of these pathogens. Here, the growth rates of the Brazilian isolates R. rickettsii str. Taiaçu, R. parkeri str. At#24, and R. rhipicephali HJ#5, were evaluated in Vero cells by quantitative polymerase chain reaction. R. rhipicephali showed different kinetic growth compared to R. rickettsii and R. parkeri. PMID:27508322

  8. Comparative growth of spotted fever group Rickettsia spp. strains in Vero cells.

    PubMed

    Silva, Arannadia Barbosa; Duarte, Myrian Morato; Vizzoni, Vinicius Figueiredo; Duré, Ana Íris de Lima; Lopéz, Diego Montenegro; Nogueira, Rita de Maria Seabra; Soares, Carlos Augusto Gomes; Machado-Ferreira, Erik; Gazêta, Gilberto Salles

    2016-08-01

    In Brazil, the spotted fever group (SFG) Rickettsia rickettsii and Rickettsia parkeri related species are the etiological agents of spotted fever rickettsiosis. However, the SFG, Rickettsia rhipicephali, that infects humans, has never been reported. The study of growth dynamics can be useful for understanding the infective and invasive capacity of these pathogens. Here, the growth rates of the Brazilian isolates R. rickettsii str. Taiaçu, R. parkeri str. At#24, and R. rhipicephali HJ#5, were evaluated in Vero cells by quantitative polymerase chain reaction. R. rhipicephali showed different kinetic growth compared to R. rickettsii and R. parkeri. PMID:27508322

  9. Biases and systematics in the observational derivation of galaxy properties: comparing different techniques on synthetic observations of simulated galaxies

    NASA Astrophysics Data System (ADS)

    Guidi, Giovanni; Scannapieco, Cecilia; Walcher, C. Jakob

    2015-12-01

    We study the sources of biases and systematics in the derivation of galaxy properties from observational studies, focusing on stellar masses, star formation rates, gas and stellar metallicities, stellar ages, magnitudes and colours. We use hydrodynamical cosmological simulations of galaxy formation, for which the real quantities are known, and apply observational techniques to derive the observables. We also analyse biases that are relevant for a proper comparison between simulations and observations. For our study, we post-process the simulation outputs to calculate the galaxies' spectral energy distributions (SEDs) using stellar population synthesis models and also generate the fully consistent far-UV-submillimetre wavelength SEDs with the radiative transfer code SUNRISE. We compared the direct results of simulations with the observationally derived quantities obtained in various ways, and found that systematic differences in all studied galaxy properties appear, which are caused by: (1) purely observational biases, (2) the use of mass-weighted and luminosity-weighted quantities, with preferential sampling of more massive and luminous regions, (3) the different ways of constructing the template of models when a fit to the spectra is performed, and (4) variations due to different calibrations, most notably for gas metallicities and star formation rates. Our results show that large differences can appear depending on the technique used to derive galaxy properties. Understanding these differences is of primary importance both for simulators, to allow a better judgement of similarities and differences with observations, and for observers, to allow a proper interpretation of the data.

  10. Biogeochemical implications of comparative growth rates of Emiliania huxleyi and Coccolithus species

    NASA Astrophysics Data System (ADS)

    Daniels, C. J.; Sheward, R. M.; Poulton, A. J.

    2014-12-01

    Coccolithophores, a diverse group of phytoplankton, make important contributions to pelagic calcite production and export, yet the comparative biogeochemical role of species other than the ubiquitous Emiliania huxleyi is poorly understood. The contribution of different coccolithophore species to total calcite production is controlled by inter-species differences in cellular calcite, growth rate and relative abundance within a mixed community. In this study we examined the relative importance of E. huxleyi and two Coccolithus species in terms of daily calcite production. Culture experiments compared growth rates and cellular calcite content of E. huxleyi (Arctic and temperate strains), Coccolithus pelagicus (novel Arctic strain) and Coccolithus braarudii (temperate strain). Despite assumptions that E. huxleyi is a fast-growing species, growth rates between the three species were broadly comparable (0.16-0.85 d-1) under identical temperature and light conditions. Emiliania huxleyi grew only 12% faster on average than C. pelagicus, and 28% faster than C. braarudii. As the cellular calcite content of C. pelagicus and C. braarudii is typically 30-80 times greater than E. huxleyi, comparable growth rates suggest that Coccolithus species have the potential to be major calcite producers in mixed populations. To further explore these results we devised a simplistic model comparing daily calcite production from Coccolithus and E. huxleyi across a realistic range of relative abundances and a wide range of relative growth rates. Using the relative differences in growth rates from our culture studies, we found that C. pelagicus would be a larger source of calcite if abundances of E. huxleyi to C. pelagicus were below 34:1. Relative abundance data collected from North Atlantic field samples (spring and summer 2010) suggest that, with a relative growth rate of 88%, C. pelagicus dominated calcite production at 69% of the sites sampled. With a more extreme difference in growth

  11. Growth characteristics of atypical mycobacteria in water and their comparative resistance to disinfectants.

    PubMed Central

    Carson, L A; Petersen, N J; Favero, M S; Aguero, S M

    1978-01-01

    With the increasing significance of group IV atypical mycobacteria as etiological agents in a variety of infections, studies were conducted to determine their growth capabilities in water and their comparative resistance to disinfectants used to decontaminate hospital equipment. Isolates of Mycobaterium chelonei (TM strains) from peritoneal fluids of patients and peritoneal dialysis machines were able to multiply in commercial distilled water, with generation times at 25 degrees C ranging from 8 to 15 h. Levels of 10(5) to 10(6) cells per ml were attained, and these stationary-phase populations declined only slightly over a 1-year period. Results of studies to determine resistance to disinfectants showed the following. (i) TM strains of M. chelonei cultured in commercial distilled water showed survivors in 2% aqueous formaldehyde (HCHO) solutions up to 24 h; in 8% HCHO, only a 2-log reduction in viable counts was observed over a 2-h sampling period. Reference ATCC strains of M. chelonei and M. fortuitum were rapidly inactivated, with no survivors after 2 h of exposure to 2% HCHO or 15 min of exposure to 8% HCHO. (ii) In 2% alkaline glutaraldehyde, TM strains survived 60 min. whereas ATCC strains showed no survivors after 2 min of contact time. (iii) All M. chelonei and M. fortuitum strains survived 60 min of exposure to concentrations of 0.3 and 0.7 microgram of free chlorine per ml at pH 7. PMID:104656

  12. Comparing immune-tumor growth models with drug therapy using optimal control

    NASA Astrophysics Data System (ADS)

    Martins, Marisa C.; Rocha, Ana Maria A. C.; Costa, M. Fernanda P.; Fernandes, Edite M. G. P.

    2016-06-01

    In this paper we compare the dynamics of three tumor growth models that include an immune system and a drug administration therapy using optimal control. The objective is to minimize a combined function of the total of tumor cells over time and a chemotherapeutic drug administration.

  13. COMPARATIVE KINETIC STUDIES OF PHOSPHATE-LIMITED GROWTH AND PHOSPHATE UPTAKE IN PHYTOPLANKTON IN CONTINUOUS CULTURE

    EPA Science Inventory

    A comparative kinetic study of phosphate-limited growth and phosphate uptake was carried out in chemostat cultures of Anabaena flos-aquae Lyng. Breb., Ankistrodesmus falcatus (Corda) Ralfs, Asterionella formosa Hass., Fragilaria crotonensis Kitt., and Microcystis sp. Lemm. For ea...

  14. Isouronium and N-hydroxyguanidinium derivatives as Cell growth inhibitors: A comparative study.

    PubMed

    Kahvedžić-Seljubac, Amila; Nathwani, Seema-Maria; Zisterer, Daniela M; Rozas, Isabel

    2016-07-19

    Based on the results obtained from a computational study on the suitability of the isouronium and N-hydroxyguanidinium cations as hydrogen bond donors/acceptors, the DNA binding of a series of isouronium derivatives was assessed by DNA thermal denaturation experiments and compared to related N-hydroxyguanidines. Due to the poor DNA binding observed, the nature of the diaromatic linker was explored by preparing the corresponding amide-linked bis-isouronium derivative and measuring its DNA affinity. Next, the inhibitory effects of the isouronium derivatives on cell viability were evaluated in two different cancer cell lines providing IC50 values in the range of 36.9-57.4 μM (HL-60, leukemia), and 17.3-33.9 μM (Kelly, neuroblastoma). These values are comparable to those previously found for the N-hydroxyguanidine series. Compounds with the -S- linker (3, 6, and 10) proved to be considerably active in the HL-60 cells and even more active in the Kelly cell line. No correlation was found between DNA minor groove binding and cell growth inhibition; hence, activity may depend on different modes of action. Further studies into the apoptotic potential of these compounds indicated that, besides inhibiting cell viability and proliferation, derivatives 9 and 10, are significant apoptosis-inducers in both cell lines. Results obtained with HL-60 cells suggest that G2/M arrest and subsequent apoptosis induced by compound 10 are associated with microtubular depolymerisation, loss of mitochondrial membrane potential and activation of the caspase cascade. Moreover, the effects of compound 10 on cell viability and apoptosis in two non-cancereous cell lines (NIH3T3 and MCF-10A) indicate none or minimal toxicity. PMID:27108161

  15. Direct observation of graphene growth and associated copper substrate dynamics by in situ scanning electron microscopy.

    PubMed

    Wang, Zhu-Jun; Weinberg, Gisela; Zhang, Qiang; Lunkenbein, Thomas; Klein-Hoffmann, Achim; Kurnatowska, Michalina; Plodinec, Milivoj; Li, Qing; Chi, Lifeng; Schloegl, R; Willinger, Marc-Georg

    2015-02-24

    This work highlights the importance of in situ experiments for an improved understanding of graphene growth on copper via metal-catalyzed chemical vapor deposition (CVD). Graphene growth inside the chamber of a modified environmental scanning electron microscope under relevant low-pressure CVD conditions allows visualizing structural dynamics of the active catalyst simultaneously with graphene nucleation and growth in an unparalleled way. It enables the observation of a complete CVD process from substrate annealing through graphene nucleation and growth and, finally, substrate cooling in real time and nanometer-scale resolution without the need of sample transfer. A strong dependence of surface dynamics such as sublimation and surface premelting on grain orientation is demonstrated, and the influence of substrate dynamics on graphene nucleation and growth is presented. Insights on the growth mechanism are provided by a simultaneous observation of the growth front propagation and nucleation rate. Furthermore, the role of trace amounts of oxygen during growth is discussed and related to graphene-induced surface reconstructions during cooling. Above all, this work demonstrates the potential of the method for in situ studies of surface dynamics on active metal catalysts. PMID:25584770

  16. Multiple new-particle growth pathways observed at the US DOE Southern Great Plains field site

    NASA Astrophysics Data System (ADS)

    Hodshire, Anna L.; Lawler, Michael J.; Zhao, Jun; Ortega, John; Jen, Coty; Yli-Juuti, Taina; Brewer, Jared F.; Kodros, Jack K.; Barsanti, Kelley C.; Hanson, Dave R.; McMurry, Peter H.; Smith, James N.; Pierce, Jeffery R.

    2016-07-01

    New-particle formation (NPF) is a significant source of aerosol particles into the atmosphere. However, these particles are initially too small to have climatic importance and must grow, primarily through net uptake of low-volatility species, from diameters ˜ 1 to 30-100 nm in order to potentially impact climate. There are currently uncertainties in the physical and chemical processes associated with the growth of these freshly formed particles that lead to uncertainties in aerosol-climate modeling. Four main pathways for new-particle growth have been identified: condensation of sulfuric-acid vapor (and associated bases when available), condensation of organic vapors, uptake of organic acids through acid-base chemistry in the particle phase, and accretion of organic molecules in the particle phase to create a lower-volatility compound that then contributes to the aerosol mass. The relative importance of each pathway is uncertain and is the focus of this work. The 2013 New Particle Formation Study (NPFS) measurement campaign took place at the DOE Southern Great Plains (SGP) facility in Lamont, Oklahoma, during spring 2013. Measured gas- and particle-phase compositions during these new-particle growth events suggest three distinct growth pathways: (1) growth by primarily organics, (2) growth by primarily sulfuric acid and ammonia, and (3) growth by primarily sulfuric acid and associated bases and organics. To supplement the measurements, we used the particle growth model MABNAG (Model for Acid-Base chemistry in NAnoparticle Growth) to gain further insight into the growth processes on these 3 days at SGP. MABNAG simulates growth from (1) sulfuric-acid condensation (and subsequent salt formation with ammonia or amines), (2) near-irreversible condensation from nonreactive extremely low-volatility organic compounds (ELVOCs), and (3) organic-acid condensation and subsequent salt formation with ammonia or amines. MABNAG is able to corroborate the observed differing growth

  17. Comparative analysis of the interaction between habitat and growth form in diatoms.

    PubMed

    Nakov, Teofil; Ashworth, Matt; Theriot, Edward C

    2015-01-01

    We characterized the evolutionary history of growth form (solitary-colonial) and its interaction with species' habitat (planktonic-benthic) across a multi-gene phylogeny encompassing a broad sample of the order-level diversity of diatoms. We treated these characters broadly, modeling the evolution of aggregation of cells into a colony irrespective of the way aggregation is achieved, and relating the growth form to a broad concept of niche location: in the plankton or benthos. The results showed that habitat shifts are rare implying conservatism in niche location at the level of large clades. On the other hand, the evolutionary history of growth form is more dynamic with evolutionary rates that vary across the tree. Analyses of a possible interaction revealed that shifts in growth form are independent of habitat and that traversing between habitats does not hinge upon species' growth form. Our findings help to fill a gap in the understanding of diatom niche and growth form macroevolution and contribute toward a platform for the comparative study of the mechanisms underlying diatom species and functional diversity. PMID:24983594

  18. Comparative data on the differentiation and growth of bone ornamentation in gnathostomes (Chordata: Vertebrata).

    PubMed

    de Buffrénil, Vivian; Clarac, François; Canoville, Aurore; Laurin, Michel

    2016-05-01

    Bone ornamentation, in the form of rounded pits framed by a network of ridges, is a frequent feature among a great diversity of gnathostome taxa. However, the basic osteogenic processes controlling the differentiation and development of these reliefs remain controversial. The present study is a broad comparative survey of this question with the classical methods used in hard tissue histology and paleohistology. Distinct processes, unevenly distributed among taxa, are involved in the creation and growth of pits and ridges. The simplest one is mere differential growth between pit bottom (slow growth) and ridge top (faster growth). The involvement of several complex remodeling processes, with the local succession of resorption and reconstruction cycles, is frequent and occurs in all major gnathostome clades. Some broad, inclusive clades (e.g., Temnospondyli) display consistency in the mechanisms controlling ornamentation, whereas other clades (e.g., Actinopterygii) are characterized by the diversity of the mechanisms involved. If osteogenic mechanisms are taken into account, bone ornamentation should be considered as a character extremely prone to homoplasy. Maximum likelihood (ML) optimizations reveal that the plesiomorphic mechanism creating ornamentation is differential apposition rate over pits (slow growth) and ridges (faster growth). In some taxas e.g., temnospondyls vs lissamphibians or pseudosuchians, bone ornamentation is likely to be a homoplastic feature due to a convergence process driven by similar selective pressures. ML models of character evolution suggest that the presence of resorption in the development of ornamentation may be selectively advantageous, although support for this conclusion is only moderate. PMID:26968432

  19. Globular-cluster stars - Results of theoretical evolution and pulsation studies compared with the observations.

    NASA Technical Reports Server (NTRS)

    Iben, I., Jr.

    1971-01-01

    Survey of recently published studies on globular clusters, and comparison of stellar evolution and pulsation theory with reported observations. The theory of stellar evolution is shown to be capable of describing, in principle, the behavior of a star through all quasi-static stages. Yet, as might be expected, estimates of bulk properties obtained by comparing observations with results of pulsation and stellar atmosphere theory differ somewhat from estimates of these same properties obtained by comparing observations with results of evolution theory. A description is given of how such estimates are obtained, and suggestions are offered as to where the weak points in each theory may lie.

  20. Comparative analysis of some models of gene regulation in mixed-substrate microbial growth.

    PubMed

    Narang, Atul

    2006-09-21

    Mixed-substrate microbial growth is of fundamental interest in microbiology and bioengineering. Several mathematical models have been developed to account for the genetic regulation of such systems, especially those resulting in diauxic growth. In this work, we compare the dynamics of three such models (Narang, 1998a. The dynamical analogy between microbial growth on mixtures of substrates and population growth of competing species. Biotechnol. Bioeng. 59, 116-121; Thattai and Shraiman, 2003. Metabolic switching in the sugar phosphotransferase system of Escherichia coli. Biophys. J. 85(2), 744-754; Brandt et al., 2004. Modelling microbial adaptation to changing availability of substrates. Water Res. 38, 1004-1013). We show that these models are dynamically similar--the initial motion of the inducible enzymes in all the models is described by the Lotka-Volterra equations for competing species. In particular, the prediction of diauxic growth corresponds to "extinction" of one of the enzymes during the first few hours of growth. The dynamic similarity occurs because in all the models, the inducible enzymes possess properties characteristic of competing species: they are required for their own synthesis, and they inhibit each other. Despite this dynamic similarity, the models vary with respect to the range of dynamics captured. The Brandt et al. model always predicts the diauxic growth pattern, whereas the remaining two models exhibit both diauxic and non-diauxic growth patterns. The models also differ with respect to the mechanisms that generate the mutual inhibition between the enzymes. In the Narang model, mutual inhibition occurs because the enzymes for each substrate enhance the dilution of the enzymes for the other substrate. The Brandt et al. model superimposes upon this dilution effect an additional mechanism of mutual inhibition. In the Thattai and Shraiman model, the mutual inhibition is entirely due to competition for the phosphoryl groups. For quantitative

  1. Comparative performance of air-lift partial nitritation processes with attached growth and suspended growth without biomass retention.

    PubMed

    Choi, Jeongdong; Ahn, Youngho

    2014-01-01

    Partial nitritation is an essential first step in anaerobic ammonium oxidation. This study compared the performance of air-lift partial nitritation reactors with attached growth (AG) and suspended growth (SG) without biomass retention using ammonium-rich recirculated liquor produced from the dewatering of anaerobically digested sludge. The steady-state results showed that the AG can effectively retain ammonium-oxidizing bacteria (AOB) with high activity and allow minimizing biomass discharge (approximately 10 mg volatile suspended solids/L) in the effluent. The nitrogen loading (based on the total reactor volume) satisfying the effluent characteristics could be suggested to be 0.42 g N/L/d for the SG, and 0.76 g N/L/d for the AG, respectively. Compared with the SG, the AG achieved a higher ammonium loading rate (approximately 1.8 times), maximal ammonium oxidation activity (48 mg N/L-h based on liquid-phase volume) under a short hydraulic retention time (HRT) and a long solids retention time (SRT > 80 d). The overall performance confirmed that AG is a promising configuration for partial nitritation in terms of the process stability, maximization of the AOB activity and minimization of the effluent biomass under a short HRT and high nitrogen loading rate. PMID:24701930

  2. Direct and in vitro observation of growth hormone receptor molecules in A549 human lung epithelial cells by nanodiamond labeling

    NASA Astrophysics Data System (ADS)

    Cheng, C.-Y.; Perevedentseva, E.; Tu, J.-S.; Chung, P.-H.; Cheng, C.-L.; Liu, K.-K.; Chao, J.-I.; Chen, P.-H.; Chang, C.-C.

    2007-04-01

    This letter presents direct observation of growth hormone receptor in one single cancer cell using nanodiamond-growth hormone complex as a specific probe. The interaction of surface growth hormone receptor of A549 human lung epithelial cells with growth hormone was observed using nanodiamond's unique spectroscopic signal via confocal Raman mapping. The growth hormone molecules were covalent conjugated to 100nm diameter carboxylated nanodiamonds, which can be recognized specifically by the growth hormone receptors of A549 cell. The Raman spectroscopic signal of diamond provides direct and in vitro observation of growth hormone receptors in physiology condition in a single cell level.

  3. Direct Observations of Three Dimensional Growth of Hydrates Hosted in Porous Media

    SciTech Connect

    Kerkar, P.; Jones, K; Kleinberg, R; Lindquist, W; Tomov, S; Feng, H; Mahajan, D

    2009-01-01

    The visualization of time-resolved three-dimensional growth of tetrahydrofuran hydrates with glass spheres of uniform size as porous media using synchrotron x-ray computed microtomography is presented. The images of hydrate patches, formed from excess tetrahydrofuran in aqueous solution, show random nucleation and growth concomitant with grain movement but independent of container-wall effect. Away from grain surfaces, hydrate surface curvature was convex showing that liquid, not hydrate, was the wetting phase, similar to ice growth in porous media. The extension of the observed behavior to methane hydrates could have implications in understanding their role in seafloor stability and climate change.

  4. Constraining lightning channel growth dynamics by comparison of time domain electromagnetic simulations to Huntsville Alabama Marx Meter Array observations

    NASA Astrophysics Data System (ADS)

    Carlson, B. E.; Bitzer, P. M.; Burchfield, J.

    2015-12-01

    Major unknowns in lightning research include the mechanism and dynamics of lightning channel extension. Such processes are most simple during the initial growth of the channel, when the channel is relatively short and has not yet branched extensively throughout the cloud. During this initial growth phase, impulsive electromagnetic emissions (preliminary breakdown pulses) can be well-described as produced by current pulses generated as the channel extends, but the overall growth rate, channel geometry, and degree of branching are not known. We approach such issues by examining electric field change measurements made with the Huntsville Alabama Marx Meter Array (HAMMA) during the first few milliseconds of growth of a lightning discharge. We compare HAMMA observations of electromagnetic emissions and overall field change to models of lightning channel growth and development and attempt to constrain channel growth rate, degree of branching, channel physical properties, and uniformity of thunderstorm electric field. Preliminary comparisons suggest that the lightning channel branches relatively early in the discharge, though more complete and detailed analysis will be presented.

  5. Comparative effects of vivax malaria, fever and diarrhoea on child growth

    PubMed Central

    Lee, Gwenyth; Yori, Pablo; Olortegui, Maribel Paredes; Pan, William; Caulfield, Laura; Gilman, Robert H; Sanders, John W; Delgado, Hermann Silva; Kosek, Margaret

    2012-01-01

    Background The adverse impact of Plasmodium vivax on child health beyond acute febrile illness is poorly studied. The effect of vivax malaria on child growth was evaluated and compared with diarrhoeal disease and non-specific fever. Methods Using data from a 43-month longitudinal cohort of children 0–72 months of age (n = 442) in the Peruvian Amazon, ponderal and linear growth velocities over 2-, 4- and 6-month periods were examined using longitudinal models and related to the incidence of disease during the same period. Results An episode of vivax malaria led to 138.6 g (95% confidence interval (CI) 81.9–195.4), 108.6 g (62.8–153.2) and 61 g (20.9–101.1) less weight gain over 2-, 4- and 6-month intervals, respectively. These deficits were larger than both diarrhoea (21.9, 17.2 and 13.8 g less weight gain, respectively) and fever (39.0, 30.3 and 25.6 g less weight gain, respectively). An incident episode of vivax also led to 0.070 cm (0.004–0.137) and 0.083 cm (0.015–0.151) less linear growth over 4 and 6 months, respectively, which were also larger than deficits from diarrhoea (0.029 and 0.028 cm, respectively) and fever (not associated with linear growth deficits). Despite the larger effect of P. vivax incident episodes on growth of a particular child, diarrhoeal disease had a larger cumulative impact on growth deficits as diarrhoeal incidence rates in this community are >10-fold higher than vivax malaria. Conclusions Disease control measures for vivax malaria and diarrhoeal disease have the potential to improve the growth of children in endemic areas. PMID:22258823

  6. Comparative assessment of growth and biodegradation potential of soil isolate in the presence of pesticides.

    PubMed

    Jilani, Seema

    2013-07-01

    In Pakistan, to increase agricultural production, higher amounts of fertilizers and pesticides are being used. The residues of the applied pesticides stay in the environment and therefore causing contamination of air, water and land. Moreover, agricultural industries are also contributing relatively high quantities of toxic pesticides into the environment. Since most of them have no treatment facilities. These pesticides may be toxic, mutagenic or carcinogenic. They may be bioaccumulated or biomagnified by the biota. Therefore its removal from environmental systems needs special attention. In this study, bacterial isolate, Pseudomonas, designated as IES-Ps-1, was used to assess its potential for pesticide removal from industrial wastewater using the biosimulator (activated sludge process). During experimental studies conducted in the flask as well as in biosimulator, it was observed that IES-Ps-1 grows normally at low concentrations of added insecticides when compared with the control test (without pesticide). However, at high concentrations the microbial count decreased but no death occurred and the culture remained in lag phase. In many cases, the growth of organisms in the presence of the particular substrate serves as an indication about its metabolic potential. However, to confirm these results, chemical oxygen demand (COD) and HPLC analysis were performed. Under aerobic culture conditions using mechanical aerators in biosimulator, almost complete removal of Cypermethrin at 20 mg/L dose occurred during 48 h. The study findings indicate that IES-Ps-1 strain, can be used for the treatment of the pesticide contaminated environment. Such study may be valuable to scientist and engineers, who are trying to develop methods for the treatment of toxic organic waste using the biological treatment process. PMID:23961243

  7. Comparative assessment of growth and biodegradation potential of soil isolate in the presence of pesticides

    PubMed Central

    Jilani, Seema

    2013-01-01

    In Pakistan, to increase agricultural production, higher amounts of fertilizers and pesticides are being used. The residues of the applied pesticides stay in the environment and therefore causing contamination of air, water and land. Moreover, agricultural industries are also contributing relatively high quantities of toxic pesticides into the environment. Since most of them have no treatment facilities. These pesticides may be toxic, mutagenic or carcinogenic. They may be bioaccumulated or biomagnified by the biota. Therefore its removal from environmental systems needs special attention. In this study, bacterial isolate, Pseudomonas, designated as IES-Ps-1, was used to assess its potential for pesticide removal from industrial wastewater using the biosimulator (activated sludge process). During experimental studies conducted in the flask as well as in biosimulator, it was observed that IES-Ps-1 grows normally at low concentrations of added insecticides when compared with the control test (without pesticide). However, at high concentrations the microbial count decreased but no death occurred and the culture remained in lag phase. In many cases, the growth of organisms in the presence of the particular substrate serves as an indication about its metabolic potential. However, to confirm these results, chemical oxygen demand (COD) and HPLC analysis were performed. Under aerobic culture conditions using mechanical aerators in biosimulator, almost complete removal of Cypermethrin at 20 mg/L dose occurred during 48 h. The study findings indicate that IES-Ps-1 strain, can be used for the treatment of the pesticide contaminated environment. Such study may be valuable to scientist and engineers, who are trying to develop methods for the treatment of toxic organic waste using the biological treatment process. PMID:23961243

  8. Comparative study on graphene growth mechanism using Ni films, Ni/Mo sheets, and Pt substrates

    NASA Astrophysics Data System (ADS)

    Lee, Byeong-Joo; Jeong, Goo-Hwan

    2014-07-01

    We demonstrate a comparative study on graphene growth mechanism using various catalytic metal substrates such as Ni thin films, Ni-deposited Mo (Ni/Mo) sheets, and Pt sheets during chemical vapor deposition (CVD). Depending on the substrates, two kinds of graphene growth mechanisms that involve either precipitation or surface adsorption of carbon have been reported. We synthesized graphene, focusing especially on the initial growth stage during CVD, by varying synthesis parameters such as synthesis time, amount of feedstock, and cooling rate after synthesis. We concluded that precipitation-driven synthesis is dominant in the case of Ni substrates whereas adsorption-driven growth is dominant in the Ni/Mo system. In the case of the Pt substrate, which is generally believed to grow by carbon precipitation, graphene growth by adsorption was found to be dominant. We believe that our results will contribute to a clearer understanding of the graphene synthesis mechanism, and development of manufacturing routes for controllable synthesis of high-quality graphenes.

  9. Direct observation of grain growth from molten silicon formed by micro-thermal-plasma-jet irradiation

    PubMed Central

    Hayashi, Shohei; Fujita, Yuji; Kamikura, Takahiro; Sakaike, Kohei; Akazawa, Muneki; Ikeda, Mitsuhisa; Hanafusa, Hiroaki; Higashi, Seiichiro

    2012-01-01

    Phase transformation of amorphous-silicon during millisecond annealing using micro-thermal-plasma-jet irradiation was directly observed using a high-speed camera with microsecond time resolution. An oval-shaped molten-silicon region adjacent to the solid phase crystallization region was clearly observed, followed by lateral large grain growth perpendicular to a liquid-solid interface. Furthermore, leading wave crystallization (LWC), which showed intermittent explosive crystallization, was discovered in front of the moving molten region. The growth mechanism of LWC has been investigated on the basis of numerical simulation implementing explosive movement of a thin liquid layer driven by released latent heat diffusion in a lateral direction. PMID:23185095

  10. Comparing GOSAT observations of localized CO2 enhancements by large emitters with inventory-based estimates

    NASA Astrophysics Data System (ADS)

    Janardanan, Rajesh; Maksyutov, Shamil; Oda, Tomohiro; Saito, Makoto; Kaiser, Johannes W.; Ganshin, Alexander; Stohl, Andreas; Matsunaga, Tsuneo; Yoshida, Yukio; Yokota, Tatsuya

    2016-04-01

    We employed an atmospheric transport model to attribute column-averaged CO2 mixing ratios (XCO2) observed by Greenhouse gases Observing SATellite (GOSAT) to emissions due to large sources such as megacities and power plants. XCO2 enhancements estimated from observations were compared to model simulations implemented at the spatial resolution of the satellite observation footprint (0.1° × 0.1°). We found that the simulated XCO2 enhancements agree with the observed over several continental regions across the globe, for example, for North America with an observation to simulation ratio of 1.05 ± 0.38 (p < 0.1), but with a larger ratio over East Asia (1.22 ± 0.32; p < 0.05). The obtained observation-model discrepancy (22%) for East Asia is comparable to the uncertainties in Chinese emission inventories (~15%) suggested by recent reports. Our results suggest that by increasing the number of observations around emission sources, satellite instruments like GOSAT can provide a tool for detecting biases in reported emission inventories.

  11. Comparing GOSAT Observations of Localized CO2 Enhancements by Large Emitters with Inventory-Based Estimates

    NASA Technical Reports Server (NTRS)

    Janardanan, Rajesh; Maksyutov, Shamil; Oda, Tomohiro; Saito, Makoto; Kaiser, Johannes W.; Ganshin, Alexander; Stohl, Andreas; Matsunaga, Tsuneo; Yoshida, Yukio; Yokota, Tatsuya

    2016-01-01

    We employed an atmospheric transport model to attribute column-averaged CO2 mixing ratios (XCO2) observed by Greenhouse gases Observing SATellite (GOSAT) to emissions due to large sources such as megacities and power plants. XCO2 enhancements estimated from observations were compared to model simulations implemented at the spatial resolution of the satellite observation footprint (0.1deg × 0.1deg). We found that the simulated XCO2 enhancements agree with the observed over several continental regions across the globe, for example, for North America with an observation to simulation ratio of 1.05 +/- 0.38 (p<0.1), but with a larger ratio over East Asia (1.22 +/- 0.32; p<0.05). The obtained observation-model discrepancy (22%) for East Asia is comparable to the uncertainties in Chinese emission inventories (approx.15%) suggested by recent reports. Our results suggest that by increasing the number of observations around emission sources, satellite instruments like GOSAT can provide a tool for detecting biases in reported emission inventories.

  12. New observational constraints on the growth of the first supermassive black holes

    SciTech Connect

    Treister, E.; Schawinski, K.; Volonteri, M.; Natarajan, P.

    2013-12-01

    We constrain the total accreted mass density in supermassive black holes at z > 6, inferred via the upper limit derived from the integrated X-ray emission from a sample of photometrically selected galaxy candidates. Studying galaxies obtained from the deepest Hubble Space Telescope images combined with the Chandra 4 Ms observations of the Chandra Deep Field-South, we achieve the most restrictive constraints on total black hole growth in the early universe. We estimate an accreted mass density <1000 M {sub ☉} Mpc{sup –3} at z ∼ 6, significantly lower than the previous predictions from some existing models of early black hole growth and earlier prior observations. These results place interesting constraints on early black hole growth and mass assembly by accretion and imply one or more of the following: (1) only a fraction of the luminous galaxies at this epoch contain active black holes; (2) most black hole growth at early epochs happens in dusty and/or less massive—as yet undetected—host galaxies; (3) there is a significant fraction of low-z interlopers in the galaxy sample; (4) early black hole growth is radiatively inefficient, heavily obscured, and/or due to black hole mergers as opposed to accretion; or (5) the bulk of the black hole growth occurs at late times. All of these possibilities have important implications for our understanding of high-redshift seed formation models.

  13. Can observational growth rate data favor the clustering dark energy models?

    NASA Astrophysics Data System (ADS)

    Mehrabi, Ahmad; Malekjani, Mohammad; Pace, Francesco

    2015-03-01

    Under the commonly used assumption that clumped objects can be well described by a spherical top-hat matter density profile, we investigate the evolution of the cosmic growth index in clustering dark energy (CDE) scenarios on sub-horizon scales. We show that the evolution of the growth index γ( z) strongly depends on the equation-of-state (EoS) parameter and on the clustering properties of the dark energy (DE) component. Performing a χ 2 analysis, we show that CDE models have a better fit to observational growth rate data points with respect to the concordance ΛCDM model. We finally determine γ( z) using an exponential parametrization and demonstrate that the growth index in CDE models presents large variations with cosmic redshift. In particular it is smaller (larger) than the theoretical value for the ΛCDM model, γ Λ ≃0.55, in the recent past (at the present time).

  14. Specific growth rate observer for the growing phase of a Polyhydroxybutyrate production process.

    PubMed

    Jamilis, Martín; Garelli, Fabricio; Mozumder, Md Salatul Islam; Volcke, Eveline; De Battista, Hernán

    2015-03-01

    This paper focuses on the specific growth rate estimation problem in a Polyhydroxybutyrate bioplastic production process by industrial fermentation. The kinetics of the process are unknown and there are uncertainties in the model parameters and inputs. During the first hours of the growth phase of the process, biomass concentration can be measured online by an optical density sensor, but as cell density increases this method becomes ineffective and biomass measurement is lost. An asymptotic observer is developed to estimate the growth rate for the case without biomass measurement based on corrections made by a pH control loop. Furthermore, an exponential observer based on the biomass measurement is developed to estimate the growth rate during the first hours, which gives the initial condition to the asymptotic observer. Error bounds and robustness to uncertainties in the models and in the inputs are found. The estimation is independent of the kinetic models of the microorganism. The characteristic features of the observer are illustrated by numerical simulations and validated by experimental results. PMID:25307471

  15. Assimilation of active and passive microwave observations for improved estimates of soil moisture and crop growth

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An Ensemble Kalman Filter-based data assimilation framework that links a crop growth model with active and passive (AP) microwave models was developed to improve estimates of soil moisture (SM) and vegetation biomass over a growing season of soybean. Complementarities in AP observations were incorpo...

  16. Observation of Rayleigh-Taylor-instability growth in a plasma regime with magnetic and viscous stabilization

    NASA Astrophysics Data System (ADS)

    Adams, Colin

    2015-11-01

    Rayleigh-Taylor-instability (RTI) growth during the interaction between a high-Mach-number, unmagnetized plasma jet and a stagnated, magnetized plasma is observed in a regime where the growth of short-wavelength modes is influenced by plasma viscosity and magnetic fields. The time evolution of mode growth at the mostly planar interface is captured by a multi-frame fast camera. Interferometry, spectroscopy, photodiode, and magnetic probe diagnostics are employed to experimentally infer ni, Te, Z , acceleration, B -->, and ion viscosity in the vicinity of the evolving interface. As the instability grows, an evolution from mode wavelengths of ~ 1 . 7 cm to ~ 2 . 8 cm is observed. The growth time (~ 10 μs) and wavelength (~ 1 cm) of the observed modes agree with theoretical predictions computed from the experimentally inferred density (~1014 cm-3), deceleration (~109 m /s2), and magnetic field (~ 15 G in direction of wavevector). Furthermore, comparisons of experimental data with idealized magnetohydrodynamic simulations (which include a physical viscosity model) suggest that both magnetic and viscous stabilization contribute to the observed mode evolution. These data are relevant for benchmarking astrophysical and magneto-inertial-fusion-relevant computations of RTI. Supported by the LANL LDRD Program; PLX facility construction supported by OFES.

  17. Helping Teenagers Stop Smoking: Comparative Observations across Youth Settings in Cardiff

    ERIC Educational Resources Information Center

    Bowles, Hannah; Maher, Alison; Sage, Robert

    2009-01-01

    Objective: This paper presents comparative observations between schools/colleges, youth centres, and specialist youth provision, in relation to delivery of the 2tuff2puff six-week smoking cessation and awareness programme to young people in Cardiff. Design: A six-week smoking cessation programme was delivered to 12-23 year olds in various youth…

  18. Comparative pharmacokinetics and pharmacodynamics of a PEGylated recombinant human growth hormone and daily recombinant human growth hormone in growth hormone-deficient children

    PubMed Central

    Hou, Ling; Chen, Zhi-hang; Liu, Dong; Cheng, Yuan-guo; Luo, Xiao-ping

    2016-01-01

    Objective Recombinant human growth hormone (rhGH) replacement therapy in children generally requires daily subcutaneous (sc) injections, which may be inconvenient for patients. Jintrolong® is a PEGylated rhGH with the purpose of weekly sc injections. The aim of the current study was to examine the pharmacokinetics, pharmacodynamics, safety, and tolerability of multiple sc doses of Jintrolong® vs daily doses of rhGH. Design and methods Twelve children with growth hormone deficiency participated in this single-center, open-label, crossover Phase I trial. All subjects received daily sc injections of rhGH at 0.0286 mg/kg/d for 7 days, followed by a 4-week washout period and six weekly doses of Jintrolong® at 0.2 mg/kg/w. Results In comparison with rhGH, sc injection of Jintrolong® produced a noticeably higher Cmax, significantly longer half-life (t1/2), and slower plasma clearance, signifying a profile suitable for long-term treatment. The ratio of the area under the concentration vs time curve (AUC) after the seventh and first injections (AUC(0–∞)7th/AUC(0–∞)1st) of rhGH was 1.02, while the AUC(0–∞)6th/AUC(0–∞)1st of Jintrolong ® was 1.03, indicating no accumulation of circulating growth hormone. There was no significant difference in the change in insulin-like growth factor-1 expression produced by 7 days of sc rhGH and weekly Jintrolong® injections. There were no severe adverse events during the trial. Conclusion The elimination rate of Jintrolong® was slower than that of sc rhGH. No progressive serum accumulation of Jintrolong® was found. The changes in insulin-like growth factor-1 expression produced by rhGH and Jintrolong® were comparable, indicating similar pharmacodynamics. Our results demonstrate that Jintrolong® is suitable for long-term growth hormone treatment in children with growth hormone deficiency. PMID:26719670

  19. Comparing the simulation of climate impacts on crop yields with observed and synthetic weather data

    NASA Astrophysics Data System (ADS)

    Qian, B.; de Jong, R.; Yang, J.; Wang, H.; Gameda, S.

    2010-12-01

    Stochastic weather generators have been used extensively in the development of climate scenarios, especially at the daily or shorter time scales, for the use as climate input to agricultural simulation models that evaluate the climate impacts on crop yields. Because generated synthetic weather data mimic the observed weather data, discrepancies between the two datasets often exist. For example, interannual variability in the synthetic data is often found to be weaker than in the observed data, i.e., the well-known overdispersion problem. Therefore, it is important to evaluate if the climate impact models are sensitive to such discrepancies between synthetic weather data and observed ones. In this study, we used a stochastic weather generator (AAFC-WG) to generate 300-yr long synthetic weather data for two Canadian sites (Swift Current on the Canadian Prairies and London in southern Ontario), based on the observed weather data for the baseline period of 1961-1990. The Decision Support System for Agrotechnology Transfer (DSSAT) v4.0 was employed to simulate crop growth and yield. Spring wheat at Swift Current and grain corn at London were simulated by the DSSAT cropping system model with three major soil types at each location, using the 30-yr observed weather data and 300-yr synthetic data, respectively. Statistical tests were performed to investigate whether differences (both mean and variance) of the simulated crop yields between the simulations with observed and synthetic weather data are statistically significant or not. Results demonstrated that the differences in simulated crop yields are often not statistically significant when synthetic weather data are used to substitute the observed data.

  20. Comparative genomic analysis of four representative plant growth-promoting rhizobacteria in Pseudomonas

    PubMed Central

    2013-01-01

    Background Some Pseudomonas strains function as predominant plant growth-promoting rhizobacteria (PGPR). Within this group, Pseudomonas chlororaphis and Pseudomonas fluorescens are non-pathogenic biocontrol agents, and some Pseudomonas aeruginosa and Pseudomonas stutzeri strains are PGPR. P. chlororaphis GP72 is a plant growth-promoting rhizobacterium with a fully sequenced genome. We conducted a genomic analysis comparing GP72 with three other pseudomonad PGPR: P. fluorescens Pf-5, P. aeruginosa M18, and the nitrogen-fixing strain P. stutzeri A1501. Our aim was to identify the similarities and differences among these strains using a comparative genomic approach to clarify the mechanisms of plant growth-promoting activity. Results The genome sizes of GP72, Pf-5, M18, and A1501 ranged from 4.6 to 7.1 M, and the number of protein-coding genes varied among the four species. Clusters of Orthologous Groups (COGs) analysis assigned functions to predicted proteins. The COGs distributions were similar among the four species. However, the percentage of genes encoding transposases and their inactivated derivatives (COG L) was 1.33% of the total genes with COGs classifications in A1501, 0.21% in GP72, 0.02% in Pf-5, and 0.11% in M18. A phylogenetic analysis indicated that GP72 and Pf-5 were the most closely related strains, consistent with the genome alignment results. Comparisons of predicted coding sequences (CDSs) between GP72 and Pf-5 revealed 3544 conserved genes. There were fewer conserved genes when GP72 CDSs were compared with those of A1501 and M18. Comparisons among the four Pseudomonas species revealed 603 conserved genes in GP72, illustrating common plant growth-promoting traits shared among these PGPR. Conserved genes were related to catabolism, transport of plant-derived compounds, stress resistance, and rhizosphere colonization. Some strain-specific CDSs were related to different kinds of biocontrol activities or plant growth promotion. The GP72 genome

  1. Comparing Regional Climate Model output to observational data sets for extreme rainfall

    NASA Astrophysics Data System (ADS)

    Sunyer, M. A.; Sørup, H. J. D.; Madsen, H.; Rosbjerg, D.; Arnbjerg-Nielsen, K.

    2012-04-01

    Climate model projections of changes in extreme rainfall are highly uncertain. In general, the analysis of model performance is the first step in studies that attempt to deal with this uncertainty. Model performance is often measured by comparing statistical properties of climate model output with observational data. However, in the assessment of model performance regarding extreme rainfall use of different observational datasets might lead to different conclusions. Rainfall data are often available either as point measurements or interpolated gridded data. Point measurements result in an unevenly spatially distributed dataset while gridded data obtained from the interpolation of point measurements provide data on an evenly distributed grid. Measurements of extreme rainfall events may be highly uncertain and underestimation is generally expected; furthermore, in gridded data extreme rainfall events tend to be smoothed due to the interpolation process. In addition, small variations in space and time of observed and modelled extremes may have a large impact on the assessment. The present study assesses the effect of the choice and interpretation of observation datasets on the conclusions drawn regarding the ability of Regional Climate Models (RCMs) to reproduce extreme events. Daily extreme rainfall over Denmark from an ensemble of RCMs is compared to three different observational datasets. The observational data considered are a point measurement dataset (ECA&D), a gridded dataset (E-Obs) and a re-analysis dataset (ERA-Interim). The results are compared with other recent studies considering climate model rainfall extremes. The study shows that in climate change studies dealing with extreme rainfall one must be aware of the effect and uncertainties from the use of different sources of observations to avoid overconfident and misleading conclusions.

  2. Observations on the formation, growth and chemical composition of aerosols in an urban environment.

    PubMed

    Crilley, Leigh R; Jayaratne, E Rohan; Ayoko, Godwin A; Miljevic, Branka; Ristovski, Zoran; Morawska, Lidia

    2014-06-17

    The charge and chemical composition of ambient particles in an urban environment were determined using a neutral particle and air ion spectrometer and an aerodyne compact time-of-flight aerosol mass spectrometer. Particle formation and growth events were observed on 20 of the 36 days of sampling, with eight of these events classified as strong. During these events, peaks in the concentration of intermediate and large ions were followed by peaks in the concentration of ammonium and sulfate, which were not observed in the organic fraction. Comparison of days with and without particle formation events revealed that ammonium and sulfate were the dominant species on particle formation days while high concentrations of biomass burning OA inhibited particle growth. Analyses of the degree of particle neutralization lead us to conclude that an excess of ammonium enabled particle formation and growth. In addition, the large ion concentration increased sharply during particle growth, suggesting that during nucleation the neutral gaseous species ammonia and sulfuric acid react to form ammonium and sulfate ions. Overall, we conclude that the mechanism of particle formation and growth involved ammonia and sulfuric acid, with limited input from organics. PMID:24847803

  3. Characteristics of proportionate growth observed in instability patterns of miscible fluids

    NASA Astrophysics Data System (ADS)

    Bischofberger, Irmgard; Ramachandran, Radha; Nagel, Sidney R.; Nagel lab Team

    2014-11-01

    As a baby mammal grows, different parts of its body develop at the nearly the same rate and thus to a good approximation in direct proportion to one another. This type of growth is called proportionate growth. As familiar as it appears to us, it is very rarely found in physical systems outside of the biological world. We here show an example of proportionate growth that occurs in the instability formed when a less viscous liquid, of viscosity ηin displaces a more viscous miscible one, of viscosity ηout. We investigate the growth of these patterns in a quasi-two-dimensional geometry. Within a range of viscosity ratios 0.1 <ηin /ηout <0.3, we observe the formation of small blunt structures that form at the edges of an inner circular region devoid of fingers. As the pattern grows, the size of these structures increases in proportion to the size of the inner circle, such that even small details in the shape of the pattern remain essentially unchanged during growth. These characteristics of proportionate growth are reflected in the shape of the interface in the third dimension as well.

  4. Observed forest sensitivity to climate implies large changes in 21st century North American forest growth.

    PubMed

    Charney, Noah D; Babst, Flurin; Poulter, Benjamin; Record, Sydne; Trouet, Valerie M; Frank, David; Enquist, Brian J; Evans, Margaret E K

    2016-09-01

    Predicting long-term trends in forest growth requires accurate characterisation of how the relationship between forest productivity and climatic stress varies across climatic regimes. Using a network of over two million tree-ring observations spanning North America and a space-for-time substitution methodology, we forecast climate impacts on future forest growth. We explored differing scenarios of increased water-use efficiency (WUE) due to CO2 -fertilisation, which we simulated as increased effective precipitation. In our forecasts: (1) climate change negatively impacted forest growth rates in the interior west and positively impacted forest growth along the western, southeastern and northeastern coasts; (2) shifting climate sensitivities offset positive effects of warming on high-latitude forests, leaving no evidence for continued 'boreal greening'; and (3) it took a 72% WUE enhancement to compensate for continentally averaged growth declines under RCP 8.5. Our results highlight the importance of locally adapted forest management strategies to handle regional differences in growth responses to climate change. PMID:27434040

  5. Advancements in Root Growth Measurement Technologies and Observation Capabilities for Container-Grown Plants

    PubMed Central

    Judd, Lesley A.; Jackson, Brian E.; Fonteno, William C.

    2015-01-01

    The study, characterization, observation, and quantification of plant root growth and root systems (Rhizometrics) has been and remains an important area of research in all disciplines of plant science. In the horticultural industry, a large portion of the crops grown annually are grown in pot culture. Root growth is a critical component in overall plant performance during production in containers, and therefore it is important to understand the factors that influence and/or possible enhance it. Quantifying root growth has varied over the last several decades with each method of quantification changing in its reliability of measurement and variation among the results. Methods such as root drawings, pin boards, rhizotrons, and minirhizotrons initiated the aptitude to measure roots with field crops, and have been expanded to container-grown plants. However, many of the published research methods are monotonous and time-consuming. More recently, computer programs have increased in use as technology advances and measuring characteristics of root growth becomes easier. These programs are instrumental in analyzing various root growth characteristics, from root diameter and length of individual roots to branching angle and topological depth of the root architecture. This review delves into the expanding technologies involved with expertly measuring root growth of plants in containers, and the advantages and disadvantages that remain. PMID:27135334

  6. Multiple new-particle growth pathways observed at the US DOE Southern Great Plains field site

    DOE PAGESBeta

    Hodshire, Anna L.; Lawler, Michael J.; Zhao, Jun; Ortega, John; Jen, Coty; Yli-Juuti, Taina; Brewer, Jared F.; Kodros, Jack K.; Barsanti, Kelley C.; Hanson, Dave R.; et al

    2016-07-28

    observed differing growth pathways, while also predicting that ELVOCs contribute more to growth than organic salt formation. However, most MABNAG model simulations tend to underpredict the observed growth rates between 10 and 20 nm in diameter; this underprediction may come from neglecting the contributions to growth from semi-to-low-volatility species or accretion reactions. Our results suggest that in addition to sulfuric acid, ELVOCs are also very important for growth in this rural setting. We discuss the limitations of our study that arise from not accounting for semi- and low-volatility organics, as well as nitrogen-containing species beyond ammonia and amines in the model. Quantitatively understanding the overall budget, evolution, and thermodynamic properties of lower-volatility organics in the atmosphere will be essential for improving global aerosol models.« less

  7. Comparative effects of contraction and angiotensin II on growth of adult feline cardiocytes in primary culture

    NASA Technical Reports Server (NTRS)

    Wada, H.; Zile, M. R.; Ivester, C. T.; Cooper, G. 4th; McDermott, P. J.

    1996-01-01

    The purposes of this study were 1) to determine whether angiotensin II causes growth of adult feline cardiocytes in long-term culture, 2) to compare the growth effects of angiotensin II with those resulting from electrically stimulated contraction, and 3) to determine whether the anabolic effects of contraction are exerted via the angiotensin type 1 receptor. Adult feline cardiocytes were cultured on laminin-coated trays in a serum-free medium. Cardiocytes were either electrically stimulated to contract (1 Hz, 5-ms pulse duration, alternating polarity) or were nonstimulated and quiescent. Quiescent cells were studied as controls and after treatment with angiotensin II (10(-8) M), losartan (10(-6) M; an angiotensin type 1-receptor antagonist), or angiotensin II plus losartan. Contracting cells were studied in the presence and absence of angiotensin II or losartan. In quiescent cardiocytes, angiotensin II treatment on day 7 significantly increased protein synthesis rates by 22% and protein content per cell by 17%. The effects of angiotensin II were completely blocked by losartan. Electrically stimulated contraction on days 4 and 7 in culture significantly increased protein synthesis rate by 18 and 38% and protein content per cell by 19 and 46%, respectively. Angiotensin II treatment did not further increase protein synthesis rate or protein content in contracting cardiocytes. Furthermore, losartan did not block the anabolic effects of contraction on protein synthesis rates or protein content. In conclusion, angiotensin II can exert a modest anabolic effect on adult feline cardiocytes in culture. In contracting feline cardiocytes, angiotensin II has no effect on growth. Growth caused by electrically stimulated contraction occurs more rapidly and is greater in magnitude than that caused by angiotensin II. Growth of contracting adult feline cardiocytes is not dependent on activation of the angiotensin receptor.

  8. Comparative studies of thin film growth on aluminium by AFM, TEM and GDOES characterization

    NASA Astrophysics Data System (ADS)

    Qi, Jiantao; Thompson, George E.

    2016-07-01

    In this present study, comparative studies of trivalent chromium conversion coating formation, associated with aluminium dissolution process, have been investigated using atomic force microscopy (AFM), transmission electron microscopy (TEM) and glow-discharge optical emission spectroscopy (GDOES). High-resolution electron micrographs revealed the evident and uniform coating initiation on the whole surface after conversion treatment for only 30 s, although a network of metal ridges was created by HF etching pre-treatment. In terms of conversion treatment process on electropolished aluminium, constant kinetics of coating growth, ∼0.30 ± 0.2 nm/s, were found after the prolonged conversion treatment for 600 s. The availability of electrolyte anions for coating deposition determined the growth process. Simultaneously, a proceeding process of aluminium dissolution during conversion treatment, of ∼0.11 ± 0.02 nm/s, was found for the first time, indicating constant kinetics of anodic reactions. The distinct process of aluminium consumption was assigned with loss of corrosion protection of the deposited coating material as evidenced in the electrochemical impedance spectroscopy. Based on the present data, a new mechanism of coating growth on aluminium was proposed, and it consisted of an activation period (0-30 s), a linear growth period (0.30 nm/s, up for 600 s) and limited growth period (0.17 nm/s, 600-1200 s). In addition, the air-drying post-treatment and a high-vacuum environment in the microscope revealed a coating shrinkage, especially in the coatings after conversion treatments for longer time.

  9. Observations of and a new model for fetch-limited wave growth

    NASA Technical Reports Server (NTRS)

    Walsh, E. J.; Hancock, D. W., III; Hines, D. E.; Swift, R. N.; Scott, J. F.

    1987-01-01

    The Surface Contour Radar (SCR) is a 36-GHz computer-controlled airborne radar which generates a false-color coded elevation map of the sea surface below the aircraft in real time. In the present paper, SCR observations are discussed which demonstrate the existence of a full developed sea state. These observations are used to judge the validity of growth rates for fetch-limited wave spectrum development and lead to new refinements in the modeling of wave generation by wind. It is noted that the observations have resolved an apparent paradox in the JONSWAP and Donelan et al. (1985) fetch-limited algorithms.

  10. Comparative age and growth of common snook Centropomus undecimalis (Pisces: Centropomidae) from coastal and riverine areas in Southern Mexico.

    PubMed

    Perera-Garcia, Martha A; Mendoza-Carranza, Manuel; Contreras-Sánchez, Wilfrido; Ferrara, Allyse; Huerta-Ortiz, Maricela; Hernández-Gómez, Raúl E

    2013-06-01

    Common snook Centropomus unidecimalis is an important commercial and fishery species in Southern Mexico, however the high exploitation rates have resulted in a strong reduction of its abundances. Since, the information about its population structure is scarce, the objective of the present research was to determine and compare the age structure in four important fishery sites. For this, age and growth of common snook were determined from specimens collected monthly, from July 2006 to March 2008, from two coastal (Barra Bosque and Barra San Pedro) and two riverine (San Pedro and Tres Brazos) commercial fishery sites in Tabasco, Mexico. Age was determined using sectioned saggitae otoliths and data analyzed by von Bertalanffy and Levenberg-Marquardt among others. Estimated ages ranged from 2 to 17 years. Monthly patterns of marginal increment formation and the percentage of otoliths with opaque rings on the outer edge demonstrated that a single annulus was formed each year. The von Bertalanffy parameters were calculated for males and females using linear adjustment and the non-linear method of Levenberg-Marquardt. The von Bertalanffy growth equations were FLt = 109.21(1-e-0.2(t+0.57)) for Barra Bosque, FLt = 94.56(1-e-027(t+0.485)) for Barra San Pedro, FLt = 97.15(1-e 0.17(t + 1.32)) for San Pedro and FLt = 83.77(1-e-026(t + 0.49)) for Tres Brazos. According to (Hotelling's T2, p < 0.05) test growth was significantly greater for females than for males. Based on the Chen test, von Bertalanffy growth curves were different among the study sites (RSS, p < 0.05). Based on the observed differences in growth parameters among sampling sites (coastal and riverine environments) future research need to be conducted on migration and population genetics, in order to delineate the stock structure of this population and support management programs. PMID:23885591

  11. Growth marks observation: preferential techniques and teeth for ageing of Spanish red deer (Cervus elaphus hispanicus).

    PubMed

    Azorit, C; Analla, M; Hervas, J; Carrasco, R; Muñoz-Cobo, J

    2002-10-01

    A total of 207 teeth belonging to 53 deer (Cervus elaphus hispanicus) from Sierra Morena (South of Spain) were analysed using histological thin sections and/or polished thick sections. Growth marks were observed in dentine and cementum of incisors, molars and canines. Tooth, region of the tooth, and type of preparation giving the best performance in terms of sharpness and interpretation ease of the growth marks, when used for Spanish deer ageing, were identified. The tissue chosen for the study was the cellular cementum of the inter-radicular pad from molars and the acellular cementum of the root from incisors, both observed through longitudinal cuts. Histological sections obtained with a conventional microtome were optimal for a reliable identification of the first growth marks. In sections thicker than 15 microm the first rest line, when observed in cementum can be confused with the cementum-dentine junction; whereas in the polished sections from molars it will not appear at all. Dentine interpretation was more difficult. Its observation should only be accomplished using cross-sections of the molar root. Secondary or accessory marks were visible in every tooth, being those from the molar pad the easiest to distinguish. Canines were the less suitable teeth for this study. PMID:12484425

  12. Demystifying the Enigma of Smoking – An Observational Comparative Study on Tobacco Smoking

    PubMed Central

    Nallakunta, Rajesh; Reddy, Sudhakara Reddy; Chennoju, Sai Kiran

    2016-01-01

    Introduction Smoking is a hazardous habit which causes definite changes in the oral cavity, consequently there exist changes in the mucosa when subjected to smoking. Palatal mucosa is first to be affected. The present study determines the palatal status in reverse smokers and conventional smokers. Aim To study and compare the clinical, cytological and histopathological changes in palatal mucosa among reverse and conventional smokers. Materials and Methods Study sample was categorized into two groups. Group 1 comprised of 20 subjects with the habit of reverse smoking and Group 2 comprised of 20 subjects with the habit of conventional smoking. Initially, clinical appearance of the palatal mucosa was recorded, followed by a cytological smear and biopsy of the involved area among all the subjects. The findings were studied clinically, the specimens were analysed cytologically and histopathologically, and compared among the two groups. Results The severity of clinical changes of the palatal mucosa among reverse smokers was statistically significant when compared to those of conventional smokers. There was no statistically significant difference observed in cytological staging between the groups with a p-value of 0.35. The histopathological changes in both the groups showed a significant difference with a p-value of 0.02. A significant positive correlation was observed between the clinical appearance, and cytological, histopathological changes. Conclusion Profound clinically aggressive changes were observed in group I compared to group II. Severity of dysplastic changes have been detected in few subjects through histopathological examination irrespective of no prominent clinical and cytological changes observed among the two groups. PMID:27190962

  13. An Automated Comparative Observation System for Sun-Induced Chlorophyll Fluorescence of Vegetation Canopies.

    PubMed

    Zhou, Xijia; Liu, Zhigang; Xu, Shan; Zhang, Weiwei; Wu, Jun

    2016-01-01

    Detecting sun-induced chlorophyll fluorescence (SIF) offers a new approach for remote sensing photosynthesis. However, to analyse the response characteristics of SIF under different stress states, a long-term time-series comparative observation of vegetation under different stress states must be carried out at the canopy scale, such that the similarities and differences in SIF change law can be summarized under different time scales. A continuous comparative observation system for vegetation canopy SIF is designed in this study. The system, which is based on a high-resolution spectrometer and an optical multiplexer, can achieve comparative observation of multiple targets. To simultaneously measure the commonly used vegetation index and SIF in the O₂-A and O₂-B atmospheric absorption bands, the following parameters are used: a spectral range of 475.9 to 862.2 nm, a spectral resolution of approximately 0.9 nm, a spectral sampling interval of approximately 0.4 nm, and the signal-to-noise ratio (SNR) can be as high as 1000:1. To obtain data for both the upward radiance of the vegetation canopy and downward irradiance data with a high SNR in relatively short time intervals, the single-step integration time optimization algorithm is proposed. To optimize the extraction accuracy of SIF, the FluorMOD model is used to simulate sets of data according to the spectral resolution, spectral sampling interval and SNR of the spectrometer in this continuous observation system. These data sets are used to determine the best parameters of Fraunhofer Line Depth (FLD), Three FLD (3FLD) and the spectral fitting method (SFM), and 3FLD and SFM are confirmed to be suitable for extracting SIF from the spectral measurements. This system has been used to observe the SIF values in O₂-A and O₂-B absorption bands and some commonly used vegetation index from sweet potato and bare land, the result of which shows: (1) the daily variation trend of SIF value of sweet potato leaves is

  14. An Automated Comparative Observation System for Sun-Induced Chlorophyll Fluorescence of Vegetation Canopies

    PubMed Central

    Zhou, Xijia; Liu, Zhigang; Xu, Shan; Zhang, Weiwei; Wu, Jun

    2016-01-01

    Detecting sun-induced chlorophyll fluorescence (SIF) offers a new approach for remote sensing photosynthesis. However, to analyse the response characteristics of SIF under different stress states, a long-term time-series comparative observation of vegetation under different stress states must be carried out at the canopy scale, such that the similarities and differences in SIF change law can be summarized under different time scales. A continuous comparative observation system for vegetation canopy SIF is designed in this study. The system, which is based on a high-resolution spectrometer and an optical multiplexer, can achieve comparative observation of multiple targets. To simultaneously measure the commonly used vegetation index and SIF in the O2-A and O2-B atmospheric absorption bands, the following parameters are used: a spectral range of 475.9 to 862.2 nm, a spectral resolution of approximately 0.9 nm, a spectral sampling interval of approximately 0.4 nm, and the signal-to-noise ratio (SNR) can be as high as 1000:1. To obtain data for both the upward radiance of the vegetation canopy and downward irradiance data with a high SNR in relatively short time intervals, the single-step integration time optimization algorithm is proposed. To optimize the extraction accuracy of SIF, the FluorMOD model is used to simulate sets of data according to the spectral resolution, spectral sampling interval and SNR of the spectrometer in this continuous observation system. These data sets are used to determine the best parameters of Fraunhofer Line Depth (FLD), Three FLD (3FLD) and the spectral fitting method (SFM), and 3FLD and SFM are confirmed to be suitable for extracting SIF from the spectral measurements. This system has been used to observe the SIF values in O2-A and O2-B absorption bands and some commonly used vegetation index from sweet potato and bare land, the result of which shows: (1) the daily variation trend of SIF value of sweet potato leaves is basically same

  15. Comparative rice seed toxicity tests using filter paper, growth pouch-tm, and seed tray methods.

    PubMed

    Wang, W

    1993-02-01

    Paper substrate, especially circular filter paper placed inside a Petri dish, has long been used for the plant seed toxicity test (PSTT). Although this method is simple and inexpensive, recent evidence indicates that it gives results that are significantly different from those obtained using a method that does not involve paper, especially when testing metal cations. The study compared PSTT using three methods: filter paper, Growth Pouch-TM, and seed tray. The Growth Pouch-TM is a commercially available device. The seed tray is a newly designed plastic receptacle placed inside a Petri dish. The results of the Growth Pouch-TM method showed no toxic effects on rice for Ag up to 40 mg L(-1) and Cd up to 20 mg L(-1). Using the seed tray method, IC50 (50% inhibitory effect concentration) values were 0.55 and 1.4 mg L(-1) for Ag and Cd, respectively. Although results of filter paper and seed tray methods were nearly identical for NaF, Cr(VI), and phenol, the toxicities of cations Ag and Cd were reduced by using the filter paper method; IC50 values were 22 and 18 mg L(-1), respectively. The results clearly indicate that paper substrate is not advisable for PSTT. PMID:24227383

  16. Comparative rice seed toxicity tests using filter paper, growth pouch-tm, and seed tray methods

    USGS Publications Warehouse

    Wang, W.

    1993-01-01

    Paper substrate, especially circular filter paper placed inside a Petri dish, has long been used for the plant seed toxicity test (PSTT). Although this method is simple and inexpensive, recent evidence indicates that it gives results that are significantly different from those obtained using a method that does not involve paper, especially when testing metal cations. The study compared PSTT using three methods: filter paper, Growth Pouch-TM, and seed tray. The Growth Pouch-TM is a commercially available device. The seed tray is a newly designed plastic receptacle placed inside a Petri dish. The results of the Growth Pouch-TM method showed no toxic effects on rice for Ag up to 40 mg L-1 and Cd up to 20 mg L-1. Using the seed tray method, IC50 (50% inhibitory effect concentration) values were 0.55 and 1.4 mg L-1 for Ag and Cd, respectively. Although results of filter paper and seed tray methods were nearly identical for NaF, Cr(VI), and phenol, the toxicities of cations Ag and Cd were reduced by using the filter paper method; IC50 values were 22 and 18 mg L-1, respectively. The results clearly indicate that paper substrate is not advisable for PSTT.

  17. Comparative Growth and Development of Spiders Reared on Live and Dead Prey

    PubMed Central

    Peng, Yu; Zhang, Fan; Gui, Shaolan; Qiao, Huping; Hose, Grant C.

    2013-01-01

    Scavenging (feeding on dead prey) has been demonstrated across a number of spider families, yet the implications of feeding on dead prey for the growth and development of individuals and population is unknown. In this study we compare the growth, development, and predatory activity of two species of spiders that were fed on live and dead prey. Pardosa astrigera (Lycosidae) and Hylyphantes graminicola (Lyniphiidae) were fed live or dead fruit flies, Drosophila melanogaster. The survival of P. astrigera and H. graminicola was not affected by prey type. The duration of late instars of P. astrigera fed dead prey were longer and mature spiders had less protein content than those fed live prey, whereas there were no differences in the rate of H. graminicola development, but the mass of mature spiders fed dead prey was greater than those fed live prey. Predation rates by P. astrigera did not differ between the two prey types, but H. graminicola had a higher rate of predation on dead than alive prey, presumably because the dead flies were easier to catch and handle. Overall, the growth, development and reproduction of H. graminicola reared with dead flies was better than those reared on live flies, yet for the larger P. astrigera, dead prey may suit smaller instars but mature spiders may be best maintained with live prey. We have clearly demonstrated that dead prey may be suitable for rearing spiders, although the success of the spiders fed such prey appears size- and species specific. PMID:24386248

  18. Comparing USGS national seismic hazard maps with internet-based macroseismic intensity observations

    NASA Astrophysics Data System (ADS)

    Mak, Sum; Schorlemmer, Danijel

    2016-04-01

    Verifying a nationwide seismic hazard assessment using data collected after the assessment has been made (i.e., prospective data) is a direct consistency check of the assessment. We directly compared the predicted rate of ground motion exceedance by the four available versions of the USGS national seismic hazard map (NSHMP, 1996, 2002, 2008, 2014) with the actual observed rate during 2000-2013. The data were prospective to the two earlier versions of NSHMP. We used two sets of somewhat independent data, namely 1) the USGS "Did You Feel It?" (DYFI) intensity reports, 2) instrumental ground motion records extracted from ShakeMap stations. Although both are observed data, they come in different degrees of accuracy. Our results indicated that for California, the predicted and observed hazards were very comparable. The two sets of data gave consistent results, implying robustness. The consistency also encourages the use of DYFI data for hazard verification in the Central and Eastern US (CEUS), where instrumental records are lacking. The result showed that the observed ground-motion exceedance was also consistent with the predicted in CEUS. The primary value of this study is to demonstrate the usefulness of DYFI data, originally designed for community communication instead of scientific analysis, for the purpose of hazard verification.

  19. Observations on Some of the Mycelial Growth and Pigmentation Characteristics of Cordyceps militaris Isolates

    PubMed Central

    Shrestha, Bhushan; Lee, Won-Ho; Han, Sang-Kuk

    2006-01-01

    Characteristic growth patterns of Cordyceps militaris isolates on various media, under varying light conditions and at varying incubation periods were examined. Light was found to be the most critical single factor in determining the density, texture, and pigmentation of the mycelial culture of the fungus. However, under the light condition, the degree of pigmentation and mycelial density were found to be affected by the incubation period and type of medium. Irrespective of the variations in medium type or incubation period, there was no pigmentation of the mycelium under dark condition. Radial growth of the mycelium was faster under dark incubation rather than under light incubation. Abundant mycelial density and darkest pigmentation of C. militaris isolates were produced in nutritionally rich media like SDAY, SMAY and CZYA, suggesting that these media may fulfill all the requirements for vegetative growth of the fungus. Growth characteristics of C. militaris isolates could be easily observed by the simple agar culture method, which would be useful to characterize the phenotypic characteristics of large number of pure cultures of the fungus under given conditions of growth factors such as medium, light and temperature. PMID:24039476

  20. Comparative study of growth of Chinese infants: Hong Kong versus Guangzhou.

    PubMed

    Leung, S S; Peng, C X; Xu, Y Y; Liu, K M; Quan, X J; Lui, S; Davies, D P

    1994-06-01

    The growth of 174 infants from Hong Kong and 221 infants from Guangzhou from birth to 2 years were compared. Ethnic origins, parental size, and birth weights were similar. Common illnesses in the two groups were upper respiratory tract infection and diarrhoea. The early infant feeding practices were different, with more breastfeeding and earlier introduction of solids in Guangzhou. Compared to those of Hong Kong, Guangzhou babies had lower weight for length in the first year of life. Within the Guangzhou group, babies totally breastfed for the first 2-4 months were heavier than those given rice cereals as supplement and they had less diarrhoea in the first 6 months. Hong Kong infants suffered more diarrhoea than the Guangzhou group. It was concluded that breastfeeding should be promoted and supported in these two cities. PMID:8078116

  1. Interstellar medium and initial stages of star formation: comparing simulations and observations

    NASA Astrophysics Data System (ADS)

    Malinen, Johanna

    2014-05-01

    Filamentary structures in interstellar molecular clouds have long been recognised as an important part of the star formation process. Recent studies have confirmed that dense cores in different stages of star formation are commonly located in the filaments. Therefore, it is important to study the structure and formation of the filaments and the cores, to understand the details of the early phases of star formation. The density structure of molecular clouds can be studied using many different methods and wavelengths. All techniques have their own drawbacks, and, therefore, it is crucial to compare the results obtained with different methods. Before making conclusions on observational data, the observational uncertainties and biases should be evaluated with simulations. This thesis concentrates on comparing simulations and observations of the early, prestellar phase of star formation. It consists of five journal articles. In two of the articles, we use large magnetohydrodynamical simulations followed by radiative transfer calculations to estimate the observational biases of the properties of interstellar dust, filaments and cores. We conclude that for normal stable cores the derived core masses are precise to some tens of percent, using correct assumptions of the dust properties. For high-density cores, the derived masses can be severely underestimated, up to one order of magnitude. However, an internal radiation source can make the dust in the core centre visible again, diminishing the observational bias. We also estimate the observational biases of dust emissivity properties. The parameters describing the filament cross-section, i.e. profile, are sensitive to noise but, for nearby clouds, can be determined with good accuracy using, e.g., Herschel data. However, line-of-sight confusion may complicate the observations, as part of the observed filaments are not physically continuous structures. In two of the articles, we compare three observational methods, namely

  2. Comparing Aircraft Observations of Snowfall to Forecasts Using Single or Two Moment Bulk Water Microphysics Schemes

    NASA Technical Reports Server (NTRS)

    Molthan, Andrew L.

    2010-01-01

    High resolution weather forecast models with explicit prediction of hydrometeor type, size distribution, and fall speed may be useful in the development of precipitation retrievals, by providing representative characteristics of frozen hydrometeors. Several single or double-moment microphysics schemes are currently available within the Weather Research and Forecasting (WRF) model, allowing for the prediction of up to three ice species. Each scheme incorporates different assumptions regarding the characteristics of their ice classes, particularly in terms of size distribution, density, and fall speed. In addition to the prediction of hydrometeor content, these schemes must accurately represent the vertical profile of water vapor to account for possible attenuation, along with the size distribution, density, and shape characteristics of ice crystals that are relevant to microwave scattering. An evaluation of a particular scheme requires the availability of field campaign measurements. The Canadian CloudSat/CALIPSO Validation Project (C3VP) obtained measurements of ice crystal shapes, size distributions, fall speeds, and precipitation during several intensive observation periods. In this study, C3VP observations obtained during the 22 January 2007 synoptic-scale snowfall event are compared against WRF model output, based upon forecasts using four single-moment and two double-moment schemes available as of version 3.1. Schemes are compared against aircraft observations by examining differences in size distribution, density, and content. In addition to direct measurements from aircraft probes, simulated precipitation can also be converted to equivalent, remotely sensed characteristics through the use of the NASA Goddard Satellite Data Simulator Unit. Outputs from high resolution forecasts are compared against radar and satellite observations emphasizing differences in assumed crystal shape and size distribution characteristics.

  3. Web-based Reanalysis Intercomparison Tools (WRIT): Comparing Reanalyses and Observational data.

    NASA Astrophysics Data System (ADS)

    Compo, G. P.; Smith, C. A.; Hooper, D. K.

    2014-12-01

    While atmospheric reanalysis datasets are widely used in climate science, many technical issues hinder comparing them to each other and to observations. The reanalysis fields are stored in diverse file architectures, data formats, and resolutions, with metadata, such as variable name and units, that also differ. Individual users have to download the fields, convert them to a common format, store them locally, change variable names, re-grid if needed, and convert units. Comparing reanalyses with observational datasets is difficult for similar reasons. Even if a dataset can be read via Open-source Project for a Network Data Access Protocol (OPeNDAP) or a similar protocol, most of this work is still needed. All of these tasks take time, effort, and money. To overcome some of the obstacles in reanalysis intercomparison, our group at the Cooperative Institute for Research in the Environmental Sciences (CIRES) at the University of Colorado and affiliated colleagues at National Oceanic and Atmospheric Administration's (NOAA's) Earth System Research Laboratory Physical Sciences Division (ESRL/PSD) have created a set of Web-based Reanalysis Intercomparison Tools (WRIT) at http://www.esrl.noaa.gov/psd/data/writ/. WRIT allows users to easily plot and compare reanalysis and observational datasets, and to test hypotheses. Currently, there are tools to plot monthly mean maps and vertical cross-sections, timeseries, and trajectories for standard pressure level and surface variables. Users can refine dates, statistics, and plotting options. Reanalysis datasets currently available include the NCEP/NCAR R1, NCEP/DOE R2, MERRA, ERA-Interim, NCEP CFSR and the 20CR. Observational datasets include those containing precipitation (e.g. GPCP), temperature (e.g. GHCNCAMS), winds (e.g. WASWinds), precipitable water (e.g. NASA NVAP), SLP (HadSLP2), and SST (NOAA ERSST). WRIT also facilitates the mission of the Reanalyses.org website as a convenient toolkit for studying the reanalysis datasets.

  4. Observation of the nanoscale epitaxial growth of diamond on Si (100) surface

    SciTech Connect

    Song, S.G.; Chen, C.L.; Mitchell, T.E.; Hackenberger, L.B.; Messier, R.

    1996-02-01

    Epitaxial growth of noncrystalline diamond thin film on Si(001) surface has been observed using high-resolution transmission electron microscopy. The epitaxial lattice relationship at diamond/Si interface has been described based on a cube-cube orientation with {ital a}{approx_equal}7{degree} tilt plus a rotation of the diamond lattice from the substrate lattice. The observed epitaxial behavior can be explained by the 3:2 lattice coincidence and the introduction of interfacial misfit dislocations. {copyright} {ital 1996 American Institute of Physics.}

  5. Mid-Continental Intensive Field Campaign Atmospheric CO2 Observations Compared to Forward Models

    NASA Astrophysics Data System (ADS)

    Diaz, L. I.; Davis, K. J.; Miles, N. L.; Richardson, S.; Schuh, A. E.; Denning, A.; Andrews, A. E.; Jacobson, A. R.; Corbin, K.

    2009-12-01

    Two commonly used approaches to study source/sinks of CO2 are the “bottom-up” and the “top-down” methods. Because of the large discrepancies between these approaches, the North America Carbon Program devised the Mid-Continental Intensive field campaign (MCI). The MCI campaign aims at improving the carbon flux estimates of both approaches with a combination of atmospheric transport models, a denser network of in-situ atmospheric CO2 measurements and agricultural inventories. The first step in evaluating and improving inverse models is to compare observed CO2 concentrations and predicted concentrations from forwards models. This study shows a model-data comparison at multiple temporal and spatial scales for the 2007 growing season. In-situ tower-based observations are compared to two different forwards models: NOAA’s Carbon Tracker and CSU’s SiBcrop-RAMS. Observations from two tall towers of the National Oceanic and Atmospheric Administration (NOAA) and five towers of Ring2 PSU network are used for this comparison. The towers are located in an intensively agricultural region of the North American continent. Comparisons to date show that both models predict higher mid-summer concentrations at three sites located in the “corn belt.” Both models have difficulty reproducing the observed monthly-average spatial gradient across these sites. The models also underestimate the maximum observed spatial gradients in daytime, daily-averaged boundary layer concentrations. These results suggest that the rapid photosynthetic rates found in corn are not yet well-simulated in these models, and that these data, when used in inversions, will provide a valuable constraint on regional fluxes.

  6. A comparative analysis of prenatal care and fetal growth in eight South American countries.

    PubMed

    Woodhouse, Cristina; Lopez Camelo, Jorge; Wehby, George L

    2014-01-01

    There has been little work that comprehensively compared the relationship between prenatal care and infant health across multiple countries using similar data sources and analytical models. Such comparative analyses are useful for understanding the background of differences in infant health between populations. We evaluated the association between prenatal care visits and fetal growth measured by birth weight (BW) in grams or low birth weight (<2500 grams; LBW) adjusted for gestational age in eight South American countries using similarly collected data across countries and the same analytical models. OLS and logistic regressions were estimated adjusting for a large set of relevant infant, maternal, and household characteristics and birth year and hospital fixed effects. Birth data were acquired from 140 hospitals that are part of the Latin American Collaborative Study of Congenital Malformations (ECLAMC) network. The analytical sample included 56,014 live-born infants (∼69% of total sample) with complete data born without congenital anomalies in the years 1996-2011 in Brazil, Argentina, Chile, Venezuela, Ecuador, Colombia, Bolivia, and Uruguay. Prenatal care visits were significantly (at p<.05) and positively associated with BW and negatively associated with LBW for all countries. The OLS coefficients ranged from 9 grams per visit in Bolivia to 36 grams in Uruguay. The association with LBW was strongest for Chile (OR = 0.87 per visit) and lowest for Argentina and Venezuela (OR = 0.95). The association decreased in the recent decade compared to earlier years. Our findings suggest that estimates of association between prenatal care and fetal growth are population-specific and may not be generalizable to other populations. Furthermore, as one of the indicators for a country's healthcare system for maternal and child health, prenatal care is a highly variable indicator between countries in South America. PMID:24625630

  7. Global observation of nitrous oxide: changes in growth rate and spatial patterns

    NASA Astrophysics Data System (ADS)

    Hall, B. D.; Dlugokencky, E. J.; Dutton, G. S.; Nance, J. D.; Crotwell, A. M.; Mondeel, D. J.; Elkins, J. W.

    2015-12-01

    Nitrous oxide (N2O) currently exerts the third largest climate forcing of the long-lived greenhouse gases, after CO2 and CH4. N2O is also involved in the destruction of stratospheric ozone. It is produced by microbial activity in soils and oceans, and also by industry. The atmospheric burden of N2O has increased more than 20% from its preindustrial level of ~270 nmol mol-1 (ppb). Much of this increase is related to the application of nitrogen-containing fertilizers, including manure. The NOAA Global Monitoring Division has measured the atmospheric mole fraction of N2O at Earth's surface in air samples collected around the globe (since the late 1970s) and at in situ sites mostly in the Western Hemisphere (since 1998). ). Measurements of the global burden and growth rate constrain global emissions, e.g. 18.2 ± 2.7 Tg N yr-1 in 2013, where most of the uncertainty is related to uncertainty in the global lifetime. The average growth rate of N2O from 1990 to 2010 was ~0.75 ppb yr-1. Since 2004, however, the growth rate has been increasing, and is now about 25% higher than the 1990-2010 average. Between 2010 and 2013 the growth rate averaged ~0.95 ppb yr-1. As the growth rate increased from 2004-2013, gradients derived from surface, zonal-mean N2O mole fraction, such the mean pole-to-pole difference, and the difference between NH temperate latitudes and the southern polar region, decreased. This suggests a change in the distribution of N2O emissions over this period. We will present our N2O data and examine trends, gradients, and other features that could shed light on recent changes in the growth rate. We will also compare N2O gradients to those of other trace gases, such as SF6.

  8. Simulations of Solar Induced Fluorescence compared to observations from GOSAT and GOME-2 Satellites

    NASA Astrophysics Data System (ADS)

    Baker, I. T.; Berry, J. A.; Frankenberg, C.; Joiner, J.; Van der Tol, C.; Lee, J. E.; Denning, S.

    2014-12-01

    Observations of Solar-Induced Fluorescence (SIF) are currently retrieved from the GOSAT and GOME-2 satellites, and will become available from OCO-2 shortly. The GOSAT (and OCO-2) satellite has a midday overpass time, while GOME-2 has a variable observation of approximately 0800-1100 local time. Previous studies have demonstrated a linear relationship between SIF and Gross Primary Productivity (GPP), but lack the ability to investigate causes of spatiotemporal variability. We demonstrate an ability to simulate SIF using a landsurface model (the Simple Biosphere Model; SIB) for direct comparison to observations. We calculate fluorescence yield based on known relationships between photosynthesis and fluorescence, and calculate total SIF using existing leaf-to-canopy scaling factors. We find that simulated SIF exceeds GOSAT retrieved SIF, especially in tropical and Boreal forests. Simulated SIF exceeds GOME-2 values in Boreal forest and in lower-productivity areas such as marginal desert and tundra. Observed SIF GOME-2 in croplands is significantly higher than simulations. SIF simulated for low- and high-productivity grassland and savanna show much less seasonal and interannual amplitude when compared to values from both satellites, implicating that model phenology and/or response to meteorological forcing is damped. Simulated SIF seasonal cycles are similar to observed from both satellites, and simulations are able to reproduce drought events such as occurred in Russia in 2010 and the Central USA in 2012. As simulated SIF more closely resembles observations, model estimates of GPP become more robust, as does our ability to understand and recreate the mechanisms involved in vegetation response to seasonal cycles and anomalous stress events such as drought.

  9. Comparing the Light Curves of Simulated Type Ia Supernovae with Observations Using Data-driven Models

    NASA Astrophysics Data System (ADS)

    Diemer, Benedikt; Kessler, Richard; Graziani, Carlo; Jordan, George C., IV; Lamb, Donald Q.; Long, Min; van Rossum, Daniel R.

    2013-08-01

    We propose a robust, quantitative method to compare the synthetic light curves of a Type Ia supernova (SN Ia) explosion model with a large set of observed SNe Ia, and derive a figure of merit for the explosion model's agreement with observations. The synthetic light curves are fit with the data-driven model SALT2 which returns values for stretch, color, and magnitude at peak brightness, as well as a goodness-of-fit parameter. Each fit is performed multiple times with different choices of filter bands and epoch range in order to quantify the systematic uncertainty on the fitted parameters. We use a parametric population model for the distribution of observed SN Ia parameters from large surveys, and extend it to represent red, dim, and bright outliers found in a low-redshift SN Ia data set. We discuss the potential uncertainties of this population model and find it to be reliable given the current uncertainties on cosmological parameters. Using our population model, we assign each set of fitted parameters a likelihood of being observed in nature, and a figure of merit based on this likelihood. We define a second figure of merit based on the quality of the light curve fit, and combine the two measures into an overall figure of merit for each explosion model. We compute figures of merit for a variety of one-, two-, and three-dimensional explosion models and show that our evaluation method allows meaningful inferences across a wide range of light curve quality and fitted parameters.

  10. Neural activation in cognitive motor processes: comparing motor imagery and observation of gymnastic movements.

    PubMed

    Munzert, Jörn; Zentgraf, Karen; Stark, Rudolf; Vaitl, Dieter

    2008-07-01

    The simulation concept suggested by Jeannerod (Neuroimage 14:S103-S109, 2001) defines the S-states of action observation and mental simulation of action as action-related mental states lacking overt execution. Within this framework, similarities and neural overlap between S-states and overt execution are interpreted as providing the common basis for the motor representations implemented within the motor system. The present brain imaging study compared activation overlap and differential activation during mental simulation (motor imagery) with that while observing gymnastic movements. The fMRI conjunction analysis revealed overlapping activation for both S-states in primary motor cortex, premotor cortex, and the supplementary motor area as well as in the intraparietal sulcus, cerebellar hemispheres, and parts of the basal ganglia. A direct contrast between the motor imagery and observation conditions revealed stronger activation for imagery in the posterior insula and the anterior cingulate gyrus. The hippocampus, the superior parietal lobe, and the cerebellar areas were differentially activated in the observation condition. In general, these data corroborate the concept of action-related S-states because of the high overlap in core motor as well as in motor-related areas. We argue that differential activity between S-states relates to task-specific and modal information processing. PMID:18425505

  11. Direct observation of crystal growth from solution using optical investigation of a growing crystal face

    NASA Technical Reports Server (NTRS)

    Lal, Ravindra

    1994-01-01

    The first technical report for the period 1 Jan. 1993 till 31 Dec. 1993 for the research entitled, 'Direct observation of crystal growth from solution using Optical Investigation of a growing crystal Face' is presented. The work on the project did not start till 1 June 1993 due to the non-availability of the required personnel. The progress of the work during the period 1 June 1993 till the end of 1993 is described. Significant progress was made for testing various optical diagnostic techniques for monitoring crystal solution. Some of the techniques that are being tested are: heterodyne detection technique, in which changes in phase are measured as a interferometric function of time/crystal growth; a conventional technique, in which a fringe brightness is measured as a function of crystal growth/time; and a Mach-Zehnder interferometric technique in which a fringe brightness is measured as a function of time to obtain information on concentration changes. During the second year it will be decided to incorporate the best interferometric technique along with the ellipsometric technique, to obtain real time in-situ growth rate measurements. A laboratory mock-up of the first two techniques were made and tested.

  12. Somatic growth of mussels Mytilus edulis in field studies compared to predictions using BEG, DEB, and SFG models

    NASA Astrophysics Data System (ADS)

    Larsen, Poul S.; Filgueira, Ramón; Riisgård, Hans Ulrik

    2014-04-01

    Prediction of somatic growth of blue mussels, Mytilus edulis, based on the data from 2 field-growth studies of mussels in suspended net-bags in Danish waters was made by 3 models: the bioenergetic growth (BEG), the dynamic energy budget (DEB), and the scope for growth (SFG). Here, the standard BEG model has been expanded to include the temperature dependence of filtration rate and respiration and an ad hoc modification to ensure a smooth transition to zero ingestion as chlorophyll a (chl a) concentration approaches zero, both guided by published data. The first 21-day field study was conducted at nearly constant environmental conditions with a mean chl a concentration of C = 2.7 μg L- 1, and the observed monotonous growth in the dry weight of soft parts was best predicted by DEB while BEG and SFG models produced lower growth. The second 165-day field study was affected by large variations in chl a and temperature, and the observed growth varied accordingly, but nevertheless, DEB and SFG predicted monotonous growth in good agreement with the mean pattern while BEG mimicked the field data in response to observed changes in chl a concentration and temperature. The general features of the models were that DEB produced the best average predictions, SFG mostly underestimated growth, whereas only BEG was sensitive to variations in chl a concentration and temperature. DEB and SFG models rely on the calibration of the half-saturation coefficient to optimize the food ingestion function term to that of observed growth, and BEG is independent of observed actual growth as its predictions solely rely on the time history of the local chl a concentration and temperature.

  13. Differentiation and growth of bone ornamentation in vertebrates: a comparative histological study among the Crocodylomorpha.

    PubMed

    de Buffrénil, V; Clarac, F; Fau, M; Martin, S; Martin, B; Pellé, E; Laurin, M

    2015-04-01

    Bone ornamentation, that is, hollow (pits and grooves) or protruding (ridges) repetitive reliefs on the surface of dermal bones, is a frequent, though poorly studied and understood, feature in vertebrates. One of the most typical examples of this characteristic is given by the Crurotarsi, a taxon formed by the crocodilians and their closest allies, which generally display deep ornamentation on skull roof and osteoderms. However, the ontogenetic process responsible for the differentiation and development of this character remains controversial. This study was conducted to settle the question on histological and microanatomical evidence in several crurotarsan taxa. Observational and experimental data in extant and extinct crocodyliforms show that bone ornamentation is initially created, and later maintained during somatic growth (that is indefinite in crocodilians), by a complex process of bone remodeling comprising local resorption of superficial bone cortices, followed by partial reconstruction. The superficial reliefs of crocodilian dermal bones are thus permanently modified through pit enlargement, drift, stretching, shrinking, or complete filling. Ridges are also remodeled in corresponding ways. These processes allow accommodation of unitary ornamental motifs to the overall dimensions of the bones during growth. A parsimony optimization based on the results of this study, but integrating also published data on bone histology in non-crocodyliform crurotarsans and some non-crurotarsan taxa, suggests that the peculiar mechanism described above for creating and maintaining bone ornamentation is a general feature of the Crurotarsi and is quite distinct from that attributed by previous authors to other vertebrates. PMID:25488816

  14. Direct TEM observations of growth mechanisms of two-dimensional MoS2 flakes

    NASA Astrophysics Data System (ADS)

    Fei, Linfeng; Lei, Shuijin; Zhang, Wei-Bing; Lu, Wei; Lin, Ziyuan; Lam, Chi Hang; Chai, Yang; Wang, Yu

    2016-07-01

    A microscopic understanding of the growth mechanism of two-dimensional materials is of particular importance for controllable synthesis of functional nanostructures. Because of the lack of direct and insightful observations, how to control the orientation and the size of two-dimensional material grains is still under debate. Here we discern distinct formation stages for MoS2 flakes from the thermolysis of ammonium thiomolybdates using in situ transmission electron microscopy. In the initial stage (400 °C), vertically aligned MoS2 structures grow in a layer-by-layer mode. With the increasing temperature of up to 780 °C, the orientation of MoS2 structures becomes horizontal. When the growth temperature reaches 850 °C, the crystalline size of MoS2 increases by merging adjacent flakes. Our study shows direct observations of MoS2 growth as the temperature evolves, and sheds light on the controllable orientation and grain size of two-dimensional materials.

  15. Direct TEM observations of growth mechanisms of two-dimensional MoS2 flakes.

    PubMed

    Fei, Linfeng; Lei, Shuijin; Zhang, Wei-Bing; Lu, Wei; Lin, Ziyuan; Lam, Chi Hang; Chai, Yang; Wang, Yu

    2016-01-01

    A microscopic understanding of the growth mechanism of two-dimensional materials is of particular importance for controllable synthesis of functional nanostructures. Because of the lack of direct and insightful observations, how to control the orientation and the size of two-dimensional material grains is still under debate. Here we discern distinct formation stages for MoS2 flakes from the thermolysis of ammonium thiomolybdates using in situ transmission electron microscopy. In the initial stage (400 °C), vertically aligned MoS2 structures grow in a layer-by-layer mode. With the increasing temperature of up to 780 °C, the orientation of MoS2 structures becomes horizontal. When the growth temperature reaches 850 °C, the crystalline size of MoS2 increases by merging adjacent flakes. Our study shows direct observations of MoS2 growth as the temperature evolves, and sheds light on the controllable orientation and grain size of two-dimensional materials. PMID:27412892

  16. Direct TEM observations of growth mechanisms of two-dimensional MoS2 flakes

    PubMed Central

    Fei, Linfeng; Lei, Shuijin; Zhang, Wei-Bing; Lu, Wei; Lin, Ziyuan; Lam, Chi Hang; Chai, Yang; Wang, Yu

    2016-01-01

    A microscopic understanding of the growth mechanism of two-dimensional materials is of particular importance for controllable synthesis of functional nanostructures. Because of the lack of direct and insightful observations, how to control the orientation and the size of two-dimensional material grains is still under debate. Here we discern distinct formation stages for MoS2 flakes from the thermolysis of ammonium thiomolybdates using in situ transmission electron microscopy. In the initial stage (400 °C), vertically aligned MoS2 structures grow in a layer-by-layer mode. With the increasing temperature of up to 780 °C, the orientation of MoS2 structures becomes horizontal. When the growth temperature reaches 850 °C, the crystalline size of MoS2 increases by merging adjacent flakes. Our study shows direct observations of MoS2 growth as the temperature evolves, and sheds light on the controllable orientation and grain size of two-dimensional materials. PMID:27412892

  17. Comparative effects of auxin and abscisic acid on growth, hydrogen ion efflux and gravitropism in primary roots of maize

    NASA Technical Reports Server (NTRS)

    Evans, M. L.; Mulkey, T. J.

    1984-01-01

    In order to test the idea that auxin action on root growth may be mediated by H(+) movement, the correlation of auxin action on growth and H(+) movement in roots was examined along with changes in H(+) efflux patterns associated with the asymmetric growth which occurs during gravitropism. The effects of indoleacetic acid (IAA) and abscisic acid (AbA) on growth, H(+) secretion, and gravitropism in roots were compared. Results show a close correlation existent between H(+) efflux and growth in maize roots. In intact roots there is strong H(+) efflux from the elongation zone. Growth-promoting concentrations of IAA stimulate H(+) efflux. During gravitropism the H(+) efflux from the elongation zone becomes asymmetric; the evidence indicates that auxin redistribution contributes to the development of acid efflux asymmetry. That AbA stimulates root growth is reflected in its ability to stimulate H(+) efflux from apical root segments.

  18. Comparing Children with ASD and Their Peers' Growth in Print Knowledge.

    PubMed

    Dynia, Jaclyn M; Brock, Matthew E; Logan, Jessica A R; Justice, Laura M; Kaderavek, Joan N

    2016-07-01

    Many children with autism spectrum disorder (ASD) struggle with reading. An increased focus on emergent literacy skills-particularly print knowledge-might improve later reading outcomes. We analyzed longitudinal measures of print knowledge (i.e., alphabet knowledge and print-concept knowledge) for 35 preschoolers with ASD relative to a sample of 35 typically developing peers. Through multilevel growth curve analysis, we found that relative to their peers, children with ASD had comparable alphabet knowledge, lower print-concept knowledge, and acquired both skills at a similar rate. These findings suggest that children with ASD are unlikely to acquire print-concept knowledge commensurate to their peers without an increased emphasis on high-quality instruction that targets this skill. PMID:27113339

  19. Experimental observations of root growth in a controlled photoelastic granular material

    NASA Astrophysics Data System (ADS)

    Mora, Serge; Bares, Jonathan; Delenne, Jean-Yves; Fourcaud, Thierry

    The mechanism of root growth in soil is a key issue to understand both how to improve plant development and how to stabilize grounds. However, no experimental studies have been carried out to directly observe root development and surrounding stress while imposing specific grain configurations or mechanical loading. We present a novel set-up which permits to observe the development of chickpea root networks in a 2D granular material made of bidisperse photoelastic discs while imposing the position of the grains, the intergranular spacing and the nature of the system confinement: (i) open cell, (ii) confined cell (iii) sheared cell. In the experimental apparatus several root development cells are treated in parallel to increase the statistical meaning of the observations. Evolution of the root network is followed as well as position and pressure inside each disc by mean of a camera and classical photoelastic techniques. Preliminary results will be presented.

  20. Direct observations of sigma phase growth and dissolution in 2205 duplex stainless steel

    SciTech Connect

    Palmer, T.A.; Elmer, J.W.; Babu, S.S.; Specht, E.D.

    2007-10-10

    The formation and growth of sigma ({sigma}) phase in a 2205 duplex stainless steel is monitored during an 850 C isothermal heat treatment using an in situ synchrotron x-ray diffraction technique. At this temperature, {sigma} phase is first observed within approximately 40 seconds of the start of the isothermal heat treatment and grows rapidly over the course of the 3600 second heat treatment to a volume fraction of approximately 13%. A simultaneous increase in the austenite ({gamma}) volume fraction and a decrease in the ferrite ({delta}) volume fraction are observed. The {sigma} phase formed at this temperature is rapidly dissolved within approximately 200 seconds when the temperature is increased to 1000 C. Accompanying this rapid dissolution of the {sigma} phase, the {delta} and {gamma} volume fractions both approach the balanced (50/50) level observed in the as-received material.

  1. Direct Observations of Sigma Phase Growth and Dissolution in 2205 Duplex Stainless Steel

    SciTech Connect

    Palmer, T; Elmer, J; Babu, S; Specht, E

    2005-06-14

    The formation and growth of sigma ({sigma}) phase in a 2205 duplex stainless steel is monitored during an 850 C isothermal heat treatment using an in situ synchrotron x-ray diffraction technique. At this temperature, {sigma} phase is first observed within approximately 40 seconds of the start of the isothermal heat treatment and grows rapidly over the course of the 3600 second heat treatment to a volume fraction of approximately 13%. A simultaneous increase in the austenite ({gamma}) volume fraction and a decrease in the ferrite ({delta}) volume fraction are observed. The {sigma} phase formed at this temperature is rapidly dissolved within approximately 200 seconds when the temperature is increased to 1000 C. Accompanying this rapid dissolution of the {sigma} phase, the {delta} and {gamma} volume fractions both approach the balanced (50/50) level observed in the as-received material.

  2. Intravitreal Anti-vascular Endothelial Growth Factor versus Observation in Acute Central Serous Chorioretinopathy: One-year Results

    PubMed Central

    Park, Sang-Uk; Lee, Seung-Jun

    2014-01-01

    Purpose To evaluate the efficacy of anti-vascular endothelial growth factor (VEGF) compared with observation for treating acute central serous chorioretinopathy (CSC). Methods A retrospective study of 36 patients with acute CSC, including 21 patients treated with anti-VEGF (anti-VEGF group) and 15 patients with observation (observation group). Patients in the anti-VEGF group received a single dose of bevacizumab or ranibizumab at baseline. Best-corrected visual acuity (BCVA), central foveal thickness (CFT) and resolution of subretinal fluid (SRF) on optical coherence tomography (OCT) were assessed. The integrity of the foveal inner segment/outer segment (IS/OS) line at 12 months was also analyzed. Results Resolution of SRF was achieved in 20 of 21 eyes in the anti-VEGF group and in 12 of 15 eyes in the observation group (p = 0.151). Mean BCVA and CFT were not different between the two groups at 12 months (p > 0.05). The amount of change in BCVA, however, differed significantly between the groups (p = 0.044). Final OCT more frequently detected the foveal IS/OS line in the anti-VEGF group than in the observation group (p = 0.012). Conclusions In terms of BCVA, anti-VEGF and observation only had similar therapeutic effects in acute CSC patients. In some patients, however, the rapid resolution of SRF by anti-VEGF might reduce the risk of photoreceptor degeneration and improve long-term visual acuity. PMID:25120339

  3. Lidar observations of mixed layer dynamics - Tests of parameterized entrainment models of mixed layer growth rate

    NASA Technical Reports Server (NTRS)

    Boers, R.; Eloranta, E. W.; Coulter, R. L.

    1984-01-01

    Ground based lidar measurements of the atmospheric mixed layer depth, the entrainment zone depth and the wind speed and wind direction were used to test various parameterized entrainment models of mixed layer growth rate. Six case studies under clear air convective conditions over flat terrain in central Illinois are presented. It is shown that surface heating alone accounts for a major portion of the rise of the mixed layer on all days. A new set of entrainment model constants was determined which optimized height predictions for the dataset. Under convective conditions, the shape of the mixed layer height prediction curves closely resembled the observed shapes. Under conditions when significant wind shear was present, the shape of the height prediction curve departed from the data suggesting deficiencies in the parameterization of shear production. Development of small cumulus clouds on top of the layer is shown to affect mixed layer depths in the afternoon growth phase.

  4. The effect of sulphate on magnesite growth: in-situ and ex-situ nanoscale observations

    NASA Astrophysics Data System (ADS)

    King, Helen E.; Satoh, Hisao; Tsukamoto, Katsuo; Putnis, Andrew

    2013-04-01

    The composition of a solution has important implications for growth mechanisms and the incorporation of impurities during growth. For example, the presence of sulphate during CO2 sequestration in Mg-silicate rocks such as ophiolites is expected to restrict magnesite (MgCO3) growth due to the formation of Mg-sulphate ion pairs in solution (Pye et al. 1998), which lower the solution supersaturation with respect to magnesite. Conversely, direct interactions of sulphate with the magnesite surface, observed during dissolution (King and Putnis, 2013), could limit the negative effects of Mg-sulphate ion pair formation in solution by aiding growth through assisted desolvation of the Mg2+ ion (e.g., Piana et al. 2006). Furthermore, if the adsorbed sulphate is incorporated into the magnesite structure during growth it removes the need for expensive SO2 flue gas scrubbers as both CO2 and SO2 can be sequestered simultaneously. To explore the implications of sulphate in solution for CO2 sequestration we have observed the growth of cleaved magnesite {104} surfaces in-situ using phase shift interferometry (PSI), a technique specially designed to monitor ultra-slow growing or dissolving mineral surfaces. In addition, we have conducted batch experiments in Teflon-lined steel autoclaves and examined the surfaces ex-situ using atomic force microscopy (AFM). All experiments were conducted at 90 ° C in solutions of 0.2 M NaHCO3 and 0.8 M NaCl or 0.4 M Na2SO4. Supersaturation of the solution was varied by changing the concentration of either MgCl2 for Cl-rich or MgSO4 in sulphate-rich solutions. For the PSI experiments a pressure of 1 MPa was used to prevent the formation of bubbles. In these experiments magnesite was grown in a flowing solution (100 μL/min) for 12 hours, whereas the batch experiments were conducted for 1-7 days under static conditions. The in-situ observations from the PSI experiments indicate that the presence of sulphate increased the rate of obtuse step

  5. Active galactic nuclei flicker: an observational estimate of the duration of black hole growth phases of ˜105 yr

    NASA Astrophysics Data System (ADS)

    Schawinski, Kevin; Koss, Michael; Berney, Simon; Sartori, Lia F.

    2015-08-01

    We present an observational constraint for the typical active galactic nucleus (AGN) phase lifetime. The argument is based on the time lag between an AGN central engine switching on and becoming visible in X-rays, and the time the AGN then requires to photoionize a large fraction of the host galaxy. Based on the typical light travel time across massive galaxies, and the observed fraction of X-ray-selected AGN without AGN-photoionized narrow lines, we estimate that the AGN phase typically lasts ˜105 yr. This lifetime is short compared to the total growth time of 107-109 yr estimated from e.g. the Soltan argument and implies that black holes grow via many such short bursts and that AGN therefore `flicker' on and off. We discuss some consequences of this flickering behaviour for AGN feedback and the analogy of X-ray binaries and AGN lifecycles.

  6. Comparing masked target transform volume (MTTV) clutter metric to human observer evaluation of visual clutter

    NASA Astrophysics Data System (ADS)

    Camp, H. A.; Moyer, Steven; Moore, Richard K.

    2010-04-01

    The Night Vision and Electronic Sensors Directorate's current time-limited search (TLS) model, which makes use of the targeting task performance (TTP) metric to describe image quality, does not explicitly account for the effects of visual clutter on observer performance. The TLS model is currently based on empirical fits to describe human performance for a time of day, spectrum and environment. Incorporating a clutter metric into the TLS model may reduce the number of these empirical fits needed. The masked target transform volume (MTTV) clutter metric has been previously presented and compared to other clutter metrics. Using real infrared imagery of rural images with varying levels of clutter, NVESD is currently evaluating the appropriateness of the MTTV metric. NVESD had twenty subject matter experts (SME) rank the amount of clutter in each scene in a series of pair-wise comparisons. MTTV metric values were calculated and then compared to the SME observers rankings. The MTTV metric ranked the clutter in a similar manner to the SME evaluation, suggesting that the MTTV metric may emulate SME response. This paper is a first step in quantifying clutter and measuring the agreement to subjective human evaluation.

  7. Airborne pulsed lidar measurements over Railroad Valley Nevada compared with GOSAT observations

    NASA Astrophysics Data System (ADS)

    Weaver, C. J.; Allan, G. R.; Riris, H.; Hasselbrack, W.; Abshire, J. B.

    2010-12-01

    We present a comparison of observations from an airborne pulsed lidar taken during a GOSAT satellite overpass. This was part of the Active Sensing of CO2 Emissions over nights Days and Seasons (ASCENDS) 2010 campaign onboard the NASA DC-8 aircraft. The NASA Goddard pulse lidar system steps a pulsed wavelength-tunable laser transmitter across the 1572.33 nm (6360 cm-1) CO2 line in thirty steps at a 330 Hz repetition rate. The laser beam is co-aligned with the receiver and directed toward nadir. The energy of the laser echoes is measured. The result is a scan of a single line at high spectral resolution. We focus on the 12 July flight over Railroad Valley Nevada which was simultaneous with a GOSAT satellite overpass. The Band 2 of the Fourier Transform Spectrometer onboard GOSAT samples from 5200 to 6400 cm-1 which includes the 6360 cm-1 line measured by our airborne lidar. While the GOSAT observations are spectrally coarser (0.2 cm-1) and sampled from space, we will compare: observed and forward modeled line shapes, retrieved CO2 column densities from both instruments and in-situ measurements where available.

  8. Assessment of the sea ice solutions in the CMIP5 compared to observations and CMIP3

    NASA Astrophysics Data System (ADS)

    Ivanova, D. P.; Gleckler, P. J.

    2012-12-01

    To evaluate the sea ice volume accurately both sea ice extent and sea ice thickness are needed which sets high demands on models (to maintain sufficient physics for reproducing realistic ice thickness distributions) and observations (getting the most from the currently short and sparse records for sea ice thickness). Here we evaluate the simulated in the CMIP5 historical ensembles sea ice solutions for the sea ice concentration (SIC) and sea ice thickness (SIT) via comparison to available observations. Using multiple observational data sets to account for uncertainty due to different algorithms used to process the satellite sensors records we validate the fidelity of the models in terms of the mean, std and seasonal cycle of the total ice area and extent, as well as, mean and seasonal spatial distributions of sea ice concentration and thickness. To examine the improvement in the latest suite of climate models we compare the CMIP5 multi-model mean characteristics to the previous CMIP3. Possible origins for the model spread are explored by investigating the correlation of the ice volume changes and ocean heat content and near surface atmospheric temperature. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  9. Comparing tests appear in model-check for normal regression with spatially correlated observations

    NASA Astrophysics Data System (ADS)

    Somayasa, Wayan; Wibawa, Gusti A.

    2016-06-01

    The problem of investigating the appropriateness of an assumed model in regression analysis was traditionally handled by means of F test under independent observations. In this work we propose a more modern method based on the so-called set-indexed partial sums processes of the least squares residuals of the observations. We consider throughout this work univariate and multivariate regression models with spatially correlated observations, which are frequently encountered in the statistical modelling in geosciences as well as in mining. The decision is drawn by performing asymptotic test of statistical hypothesis based on the Kolmogorov-Smirnov and Cramér-von Misses functionals of the processes. We compare the two tests by investigating the power functions of the test. The finite sample size behavior of the tests are studied by simulating the empirical probability of rejections of H 0. It is shown that for univariate model the KS test seems to be more powerful. Conversely the Cramér-von Mises test tends to be more powerful than the KS test in the multivariate case.

  10. A comparative study between a high-gain interconnected observer and an adaptive observer applied to IM-based WECS

    NASA Astrophysics Data System (ADS)

    Naifar, Omar; Boukettaya, Ghada; Oualha, Abdelmajid; Ouali, Abderrazak

    2015-05-01

    This paper is devoted to the investigation of the potentialities of induction motor sensorless strategies in speed control applications. A comparison study is carried out between two observation approaches dedicated to speed control strategies of induction machine (IM)-based wind energy conversion systems (WECS) under parametric variations, such as: i) the adaptive observer approach, which is based on the speed adaptation law and ii) the interconnected observer, that offers robustness and stability of the system with reduced CPU time. The comparison study is achieved considering four performance criteria: stability, robustness with respect to the variations of the machine inductances, robustness with respect to the variations of the machine resistances, feasibility of the torque estimation. It has been found that the introduced interconnected observer exhibits a higher performance than the traditional adaptive one, with respect to the above-cited comparison criteria.

  11. Time Series Analysis of Remote Sensing Observations for Citrus Crop Growth Stage and Evapotranspiration Estimation

    NASA Astrophysics Data System (ADS)

    Sawant, S. A.; Chakraborty, M.; Suradhaniwar, S.; Adinarayana, J.; Durbha, S. S.

    2016-06-01

    Satellite based earth observation (EO) platforms have proved capability to spatio-temporally monitor changes on the earth's surface. Long term satellite missions have provided huge repository of optical remote sensing datasets, and United States Geological Survey (USGS) Landsat program is one of the oldest sources of optical EO datasets. This historical and near real time EO archive is a rich source of information to understand the seasonal changes in the horticultural crops. Citrus (Mandarin / Nagpur Orange) is one of the major horticultural crops cultivated in central India. Erratic behaviour of rainfall and dependency on groundwater for irrigation has wide impact on the citrus crop yield. Also, wide variations are reported in temperature and relative humidity causing early fruit onset and increase in crop water requirement. Therefore, there is need to study the crop growth stages and crop evapotranspiration at spatio-temporal scale for managing the scarce resources. In this study, an attempt has been made to understand the citrus crop growth stages using Normalized Difference Time Series (NDVI) time series data obtained from Landsat archives (http://earthexplorer.usgs.gov/). Total 388 Landsat 4, 5, 7 and 8 scenes (from year 1990 to Aug. 2015) for Worldwide Reference System (WRS) 2, path 145 and row 45 were selected to understand seasonal variations in citrus crop growth. Considering Landsat 30 meter spatial resolution to obtain homogeneous pixels with crop cover orchards larger than 2 hectare area was selected. To consider change in wavelength bandwidth (radiometric resolution) with Landsat sensors (i.e. 4, 5, 7 and 8) NDVI has been selected to obtain continuous sensor independent time series. The obtained crop growth stage information has been used to estimate citrus basal crop coefficient information (Kcb). Satellite based Kcb estimates were used with proximal agrometeorological sensing system

  12. Evolution of small cumulus clouds in Florida: observations of pulsating growth

    NASA Astrophysics Data System (ADS)

    French, Jeffrey R.; Vali, Gabor; Kelly, Robert D.

    Observations have been made in six small cumulus clouds using instrumented aircraft, a ground-based radar, and a 95 GHz airborne Doppler radar. The clouds occurred on two days during the Small Cumulus Microphysics Study in east-central Florida, summer 1995. Cloud tops were below 3 km and in-cloud temperatures were warmer than 10°C. Maximum observed reflectivity factors were less than 0 dBZ. The evolution of the kinematics of the observed clouds was tracked using measurements from both radars. High-resolution cross-sections of reflectivity and vertical Doppler velocity from the airborne radar appear remarkably similar to fine-scale models of convection reported in the literature. In general, each cloud resembled a collection of individual bubbles ascending through the boundary layer. During the growth phase of a bubble, a positive correlation existed between vertical velocity and reflectivity. As bubbles penetrated further into the inversion, entrainment/detrainment led to a weakening or, in some cases, a reversal of this correlation. Growth of subsequent bubbles ascending through remnants of earlier bubbles were aided by an increase in the amount of moisture in the environment resulting from earlier detrainment of cloudy air, and thus were able to achieve higher altitudes than their predecessors.

  13. Aerosol observations and growth rates downwind of the anvil of a deep tropical thunderstorm

    NASA Astrophysics Data System (ADS)

    Waddicor, D. A.; Vaughan, G.; Choularton, T. W.; Bower, K. N.; Coe, H.; Gallagher, M.; Williams, P. I.; Flynn, M.; Volz-Thomas, A.; Pätz, H.-W.; Isaac, P.; Hacker, J.; Arnold, F.; Schlager, H.; Whiteway, J. A.

    2012-07-01

    We present a case study of Aitken and accumulation mode aerosol observed downwind of the anvil of a deep tropical thunderstorm. The measurements were made by condensation nuclei counters flown on the Egrett high-altitude aircraft from Darwin during the ACTIVE campaign, in monsoon conditions producing widespread convection over land and ocean. Maximum measured concentrations of aerosol with diameter greater than 10 nm were 25 000 cm-3 (STP). By calculating back-trajectories from the observations, and projecting onto infrared satellite images, the time since the air exited cloud was estimated. In this way a time scale of about 3 hours was derived for the Aitken aerosol concentration to reach its peak. We examine the hypothesis that the growth in aerosol concentrations can be explained by production of sulphuric acid from SO2 followed by particle nucleation and coagulation. Estimates of the sulphuric acid production rate show that the observations are only consistent with this hypothesis if the particles coagulate to sizes >10 nm much more quickly than is suggested by current theory. Alternatively, other condensible gases (possibly organic) drive the growth of aerosol particles in the TTL.

  14. Photoelectron fluxes observed by FAST compared with model predictions incorporating SNOE observations of the solar soft X-ray irradiance

    NASA Astrophysics Data System (ADS)

    Bailey, S. M.; Peterson, W. K.; Solomon, S. C.; Carlson, C. W.; McFadden, J. P.

    2001-12-01

    Photoelectrons are those electrons produced when atoms or molecules in the upper atmosphere are photoionized. These electrons carry the excess energy of the photon remaining from the ionization and can have energies up to and greater than 1 keV. Photoelectrons are important in that they play a significant role in the energetics of the upper atmosphere, resulting in ionization, dissociation, and excitation of atoms and molecules. There have been long standing issues with regard to understanding the magnitude of the terrestrial photoelectron flux as models have not been able to reproduce the observations without scaling the solar soft X-ray irradiance by factors of two to four. The Fast Auroral Snapshot (FAST) spacecraft was launched in August of 1996. While its primary goals focus on the study of auroral energetic particles, in January of 1999 it began making low-latitude observations. From measurements by the FAST energetic electron sensor, upward flowing photoelectron fluxes in the energy range of 50 eV to 1 keV have been obtained. These measurements are in agreement with earlier measurements of the terrestrial photoelectron flux. The Student Nitric Oxide Explorer (SNOE) spacecraft was launched in February of 1998. Since then it has been making daily observations of the solar soft X-ray irradiance in bandpasses of 2 - 7, 6 - 19, and 17 - 20 nm. SNOE observes larger values of the solar soft X-ray irradiance than reported by earlier observations or predicted by empirical models; however, the SNOE observations are in agreement with many suggestions of the solar soft X-ray irradiance obtained from geophysical observations such as airglow and electron densities. These irradiance measurements are used in a photoelectron model that includes transport. Observations of photoelectron fluxes for the first solar rotation of 1999 are modeled. The model photoelectron spectra are in good agreement with the observed photoelectron spectra over most of the 50 eV to 1 keV energy

  15. Comparing ADAPT-WSA Model Predictions With EUV And Solar Wind Observations

    NASA Astrophysics Data System (ADS)

    Arge, Charles; Henney, C. J.; Shurkin, K.; Toussaint, W.; Koller, J.; Harvey, J. W.

    2011-05-01

    Global estimates of the solar photospheric magnetic field distribution are critical for space weather forecasting. These global maps are the essential data input for accurate modeling of the corona and solar wind, which is vital for gaining the basic understanding necessary to improve forecasting models needed for Air Force operations. We are now testing the global photospheric field maps generated by the Air Force Data Assimilative Photospheric flux Transport (ADAPT) model as input to the WSA coronal and solar wind model. ADAPT incorporates the Los Alamos National Laboratory data assimilation methodology with a modified version of the Worden and Harvey photospheric magnetic flux transport model. The ADAPT maps provide a more instantaneous snapshot of the global photospheric field distribution compared to traditional synoptic maps. In this presentation, we make a detailed comparison of WSA coronal and solar wind model output with STEREO EUVI disk observations and in situ plasma observations from the STEREO and ACE spacecraft. The current orbital configuration of the two STEREO spacecraft is such that they provide a nearly instantaneous global snapshot of the Sun's coronal hole distribution. In addition, the STEREO observations along with those from the ACE spacecraft provide three widely spaced ecliptic locations at 1 AU to sample the solar wind plasma. In combination, these differing observations from multiple spacecraft provide a unique and highly sensitive test of the ability of the WSA model to capture the global coronal hole and solar wind structure. This is done using both ADAPT and standard updated photospheric field maps as input to the model.

  16. Real-time ESR observation during film growth of a-Si:H

    SciTech Connect

    Yamasaki, S.; Umeda, T.; Isoya, J.; Tanaka, K.

    1997-07-01

    In-situ electron-spin-resonance (ESR) measurements of film growth of hydrogenated amorphous silicon (a-Si:H) using a remote hydrogen plasma technique have been performed. The Si dangling-bond signal in a-Si:H during and after deposition has been detected, in addition to the gas-phase ESR signals both of atomic hydrogen and photo-excited SiH{sub x} molecules. Dynamic changes of the Si dangling-bond signal intensity were observed when the deposition started and stopped, which has suggested the existence of a subsurface region with higher spin density than that in the bulk region.

  17. Growth of a young pingo in the Canadian Arctic observed by RADARSAT-2 interferometric satellite radar

    NASA Astrophysics Data System (ADS)

    Samsonov, Sergey V.; Lantz, Trevor C.; Kokelj, Steven V.; Zhang, Yu

    2016-04-01

    Advancements in radar technology are increasing our ability to detect Earth surface deformation in permafrost environments. In this paper we use satellite Differential Interferometric Synthetic Aperture Radar (DInSAR) to describe the growth of a large, relatively young pingo in the Tuktoyaktuk Coastlands. High-resolution RADARSAT-2 imagery (2011-2014) analyzed with the Multidimensional Small Baseline Subset (MSBAS) DInSAR revealed a maximum 2.7 cm yr-1 of domed uplift located in a drained lake basin. Satellite measurements suggest that this feature is one of the largest diameter pingos in the region that is presently growing. Observed changes in elevation were modeled as a 348 × 290 m uniformly loaded elliptical plate with clamped edge. Analysis of historical aerial photographs suggested that ground uplift at this location initiated sometime between 1935 and 1951 following drainage of the residual pond. Uplift is largely due to the growth of intrusive ice, because the 9 % expansion of pore water associated with permafrost aggradation into saturated sands is not sufficient to explain the observed short- and long-term deformation rates. The modeled thickness of ice-rich permafrost using the Northern Ecosystem Soil Temperature (NEST) was consistent with the maximum height of this feature. Modeled permafrost aggradation from 1972 to 2014 approximated elevation changes estimated from aerial photographs for that time period. Taken together, these lines of evidence indicate that uplift is at least in part a result of freezing of the sub-pingo water lens. Seasonal variations in the uplift rate seen in the DInSAR data closely match the modeled seasonal pattern in the deepening rate of freezing front. This study demonstrates that interferometric satellite radar can detect and contribute to understanding the dynamics of terrain uplift in response to permafrost aggradation and ground ice development in remote polar environments. The present-day growth rate is smaller than

  18. Comparative effects of sodium butyrate and flavors on feed intake of lactating sows and growth performance of piglets.

    PubMed

    Wang, Jun; Yang, Mei; Xu, Shengyu; Lin, Yan; Che, Lianqiang; Fang, Zhengfeng; Wu, De

    2014-06-01

    We examined the effects of sodium butyrate and flavors on feed intake of lactating sows and growth performance of piglets. A total of 52 primiparous sows (Large White) were randomly divided into four treatments (n = 13) and received 6 g/kg sodium butyrate (SB), fruit-milk (FM) flavor and fruit-milk-anise (FMA) flavor with pair feeding to the mothers receiving the control diet. The feeding trial lasted for 29 days, including 21 days of nursing and 8 days of post-weaning period, respectively. The nursing and weaning piglets received creep diets with the same flavor or SB supplement as their mother. The results showed that FMA flavor increased average daily feed intake (ADFI) of lactating sows (P < 0.01), as well as improved litter weight gain (P = 0.05) and ADFI (P < 0.01) of nursing pigs among treatments. Indeed, greater ADFI and average daily gain of weaning piglets for the initial 8 days after weaning was observed in the FMA group compared with those in the control group (P < 0.01). These findings indicated that adding FMA flavor was superior to SB for increasing feed intake of lactating sows and improving growth performance of piglets. PMID:24773759

  19. Comparative physiology of allopatric Populus species: geographic clines in photosynthesis, height growth, and carbon isotope discrimination in common gardens

    PubMed Central

    Soolanayakanahally, Raju Y.; Guy, Robert D.; Street, Nathaniel R.; Robinson, Kathryn M.; Silim, Salim N.; Albrectsen, Benedicte R.; Jansson, Stefan

    2015-01-01

    Populus species with wide geographic ranges display strong adaptation to local environments. We studied the clinal patterns in phenology and ecophysiology in allopatric Populus species adapted to similar environments on different continents under common garden settings. As a result of climatic adaptation, both Populus tremula L. and Populus balsamifera L. display latitudinal clines in photosynthetic rates (A), whereby high-latitude trees of P. tremula had higher A compared to low-latitude trees and nearly so in P. balsamifera (p = 0.06). Stomatal conductance (gs) and chlorophyll content index (CCI) follow similar latitudinal trends. However, foliar nitrogen was positively correlated with latitude in P. balsamifera and negatively correlated in P. tremula. No significant trends in carbon isotope composition of the leaf tissue (δ13C) were observed for both species; but, intrinsic water-use efficiency (WUEi) was negatively correlated with the latitude of origin in P. balsamifera. In spite of intrinsically higher A, high-latitude trees in both common gardens accomplished less height gain as a result of early bud set. Thus, shoot biomass was determined by height elongation duration (HED), which was well approximated by the number of days available for free growth between bud flush and bud set. We highlight the shortcoming of unreplicated outdoor common gardens for tree improvement and the crucial role of photoperiod in limiting height growth, further complicating interpretation of other secondary effects. PMID:26236324

  20. Comparative physiology of allopatric Populus species: geographic clines in photosynthesis, height growth, and carbon isotope discrimination in common gardens.

    PubMed

    Soolanayakanahally, Raju Y; Guy, Robert D; Street, Nathaniel R; Robinson, Kathryn M; Silim, Salim N; Albrectsen, Benedicte R; Jansson, Stefan

    2015-01-01

    Populus species with wide geographic ranges display strong adaptation to local environments. We studied the clinal patterns in phenology and ecophysiology in allopatric Populus species adapted to similar environments on different continents under common garden settings. As a result of climatic adaptation, both Populus tremula L. and Populus balsamifera L. display latitudinal clines in photosynthetic rates (A), whereby high-latitude trees of P. tremula had higher A compared to low-latitude trees and nearly so in P. balsamifera (p = 0.06). Stomatal conductance (g s) and chlorophyll content index (CCI) follow similar latitudinal trends. However, foliar nitrogen was positively correlated with latitude in P. balsamifera and negatively correlated in P. tremula. No significant trends in carbon isotope composition of the leaf tissue (δ(13)C) were observed for both species; but, intrinsic water-use efficiency (WUEi) was negatively correlated with the latitude of origin in P. balsamifera. In spite of intrinsically higher A, high-latitude trees in both common gardens accomplished less height gain as a result of early bud set. Thus, shoot biomass was determined by height elongation duration (HED), which was well approximated by the number of days available for free growth between bud flush and bud set. We highlight the shortcoming of unreplicated outdoor common gardens for tree improvement and the crucial role of photoperiod in limiting height growth, further complicating interpretation of other secondary effects. PMID:26236324

  1. Comparing satellite- to ground-based automated and manual cloud coverage observations - a case study

    NASA Astrophysics Data System (ADS)

    Werkmeister, A.; Lockhoff, M.; Schrempf, M.; Tohsing, K.; Liley, B.; Seckmeyer, G.

    2015-05-01

    In this case study we compare cloud fractional cover measured by radiometers on polar satellites (AVHRR) and on one geostationary satellite (SEVIRI) to ground-based manual (SYNOP) and automated observations by a cloud camera (Hemispherical Sky Imager, HSI). These observations took place in Hannover, Germany, and in Lauder, New Zealand, over time frames of 3 and 2 months, respectively. Daily mean comparisons between satellite derivations and the ground-based HSI found the deviation to be 6 ± 14% for AVHRR and 8 ± 16% for SEVIRI, which can be considered satisfactory. AVHRR's instantaneous differences are smaller (2 ± 22%) than instantaneous SEVIRI cloud fraction estimates (8 ± 29%) when compared to HSI due to resolution and scenery effect issues. All spaceborne observations show a very good skill in detecting completely overcast skies (cloud cover ≥ 6 oktas) with probabilities between 92 and 94% and false alarm rates between 21 and 29% for AVHRR and SEVIRI in Hannover, Germany. In the case of a clear sky (cloud cover lower than 3 oktas) we find good skill with detection probabilities between 72 and 76%. We find poor skill, however, whenever broken clouds occur (probability of detection is 32% for AVHRR and 12% for SEVIRI in Hannover, Germany). In order to better understand these discrepancies we analyze the influence of algorithm features on the satellite-based data. We find that the differences between SEVIRI and HSI cloud fractional cover (CFC) decrease (from a bias of 8 to almost 0%) with decreasing number of spatially averaged pixels and decreasing index which determines the cloud coverage in each "cloud-contaminated" pixel of the binary map. We conclude that window size and index need to be adjusted in order to improve instantaneous SEVIRI and AVHRR estimates. Due to its automated operation and its spatial, temporal and spectral resolution, we recommend as well that more automated ground-based instruments in the form of cloud cameras should be installed

  2. Quantitative observations of hydrogen-induced, slow crack growth in a low alloy steel

    NASA Technical Reports Server (NTRS)

    Nelson, H. G.; Williams, D. P.

    1973-01-01

    Hydrogen-induced slow crack growth, da/dt, was studied in AISI-SAE 4130 low alloy steel in gaseous hydrogen and distilled water environments as a function of applied stress intensity, K, at various temperatures, hydrogen pressures, and alloy strength levels. At low values of K, da/dt was found to exhibit a strong exponential K dependence (Stage 1 growth) in both hydrogen and water. At intermediate values of K, da/dt exhibited a small but finite K dependence (Stage 2), with the Stage 2 slope being greater in hydrogen than in water. In hydrogen, at a constant K, (da/dt) sub 2 varied inversely with alloy strength level and varied essentially in the same complex manner with temperature and hydrogen pressure as noted previously. The results of this study provide support for most of the qualitative predictions of the lattice decohesion theory as recently modified by Oriani. The lack of quantitative agreement between data and theory and the inability of theory to explain the observed pressure dependence of slow crack growth are mentioned and possible rationalizations to account for these differences are presented.

  3. Comparative Analysis of Human Growth Hormone in Serum Using SPRi, Nano-SPRi and ELISA Assays

    PubMed Central

    Henrich, Vincent C.; Sandros, Marinella G.

    2016-01-01

    Sensitive and selective methods for the detection of human growth hormone (hGH) over a wide range of concentrations (high levels of 50-100 ng ml−1 and minimum levels of 0.03 ng ml−1) in circulating blood are essential as variable levels may indicate altered physiology. For example, growth disorders occurring in childhood can be diagnosed by measuring levels of hGH in blood. Also, the misuse of recombinant hGH in sports not only poses an ethical issue it also presents serious health threats to the abuser. One popular strategy for measuring hGH misuse, relies on the detection of the ratio of 22 kDa hGH to total hGH, as non-22 kDa endogenous levels drop after exogenous recombinant hGH (rhGH) administration.Surface plasmon resonance imaging (SPRi) is an analytical tool that allows direct (label-free) monitoring and visualization of biomolecular interactions by recording changes of the refractive index adjacent to the sensor surface in real time. In contrast, the most frequently used colorimetric method, enzyme-linked immunosorbent assay (ELISA) uses enzyme labeled detection antibodies to indirectly measure analyte concentration after the addition of a substrate that induces a color change. To increase detection sensitivity, amplified SPRi uses a sandwich assay format and near infrared quantum dots (QDs) to increase signal strength. After direct SPRi detection of recombinant rhGH in spiked human serum, the SPRi signal is amplified by the sequential injection of detection antibody coated with near-infrared QDs (Nano-SPRi). In this study, the diagnostic potential of direct and amplified SPRi was assessed for measuring rhGH spiked in human serum and compared directly with the capabilities of a commercially available ELISA kit. PMID:26780354

  4. Comparative Analysis of Human Growth Hormone in Serum Using SPRi, Nano-SPRi and ELISA Assays.

    PubMed

    Vance, Stephen; Zeidan, Effat; Henrich, Vincent C; Sandros, Marinella G

    2016-01-01

    Sensitive and selective methods for the detection of human growth hormone (hGH) over a wide range of concentrations (high levels of 50-100 ng ml(-) (1) and minimum levels of 0.03 ng ml(-) (1)) in circulating blood are essential as variable levels may indicate altered physiology. For example, growth disorders occurring in childhood can be diagnosed by measuring levels of hGH in blood. Also, the misuse of recombinant hGH in sports not only poses an ethical issue it also presents serious health threats to the abuser. One popular strategy for measuring hGH misuse, relies on the detection of the ratio of 22 kDa hGH to total hGH, as non-22 kDa endogenous levels drop after exogenous recombinant hGH (rhGH) administration. Surface plasmon resonance imaging (SPRi) is an analytical tool that allows direct (label-free) monitoring and visualization of biomolecular interactions by recording changes of the refractive index adjacent to the sensor surface in real time. In contrast, the most frequently used colorimetric method, enzyme-linked immunosorbent assay (ELISA) uses enzyme labeled detection antibodies to indirectly measure analyte concentration after the addition of a substrate that induces a color change. To increase detection sensitivity, amplified SPRi uses a sandwich assay format and near infrared quantum dots (QDs) to increase signal strength. After direct SPRi detection of recombinant rhGH in spiked human serum, the SPRi signal is amplified by the sequential injection of detection antibody coated with near-infrared QDs (Nano-SPRi). In this study, the diagnostic potential of direct and amplified SPRi was assessed for measuring rhGH spiked in human serum and compared directly with the capabilities of a commercially available ELISA kit. PMID:26780354

  5. Comparative studies on the influence of "simulated weigthlessness" on fish otolith growth

    NASA Astrophysics Data System (ADS)

    Brungs, Sonja; Hendrik Anken, Ralf; Li, Xiao-Yan; Hauslage, Jens; Wang, Gaohong; Liu, Yongding; Hilbig, Reinhard; Hemmersbach, Ruth

    Stimulus dependence is a general feature of all developing sensory systems. Concerning the vestibular organ of fish, it has been shown earlier that the growth of inner ear otoliths of developing Cichlid fish (Oreochromis mossambicus) and Zebrafish (Danio rerio) is slowed down by increased gravity (hypergravity) as an adaptation. Several studies proposed that otolith growth actively is adjusted via a feedback mechanism to produce a test mass of the appropriate physical capacity. Applying diminished gravity such as microgravity during spaceflight yielded an opposite effect, i.e., larger than normal otoliths in swordtails Xiphophorus helleri. Since there are no data on spaceflown early larval stages of the Cichlid fish and the Zebrafish available, these model organisms were subjected to simulated weightlessness using a submersed clinostat with one axis of rotation (O. mossambicus) and rotating-wall vessels (RWVs; O. mossambicus was maintained within a submersed RWV, which was recently developed at DLR, whereas D. rerio was kept within a modified RWV, developed by NASA). Developmental stages were subjected to clinorotation (60 rpm) and wall vessel rotation (Cichlid fish: 44 rpm; Zebrafish: 12.5 rpm; at these speeds, the larvae did neither sediment nor were they centrifuged away from the center of the RWVs) at a point of time when inner ear otolith mineralisation began. The experimental runs were discontinued when the animals hatched (O. mossambicus, stage 12, reached after 2-3 days at 22° C) or when they began to actively move within the devices (D. rerio, after 6 days at 28° C). After clinostat exposure, both utricular and saccular otoliths (Lapilli and Sagittae, respectively) of the Cichlids were significantly larger as compared to otoliths from the 1g controls. A similar result was obtained after wall vessel rotation for 3 and 6 days of the Zebrafish. These results support the idea that a feedback mechanism correlates the gravity level with the physical capacity

  6. Laser observations of wave growth and foam density for fetch limited 25 M/SEC winds

    NASA Technical Reports Server (NTRS)

    Ross, D. B.; Cardone, V.

    1970-01-01

    The variability of sea surface conditions has been observed from a low flying aircraft by a laser wave profiling system for fetch limited wind speeds of 25 M/SEC. in the North Sea. Wave profiles obtained with the laser system have been analyzed and show that wave growth occurs simultaneously at all frequencies and that an equilibrium value for the higher frequency components is eventually reached, but not before substantially higher (overshoot) values are obtained. Simultaneous photography of the surface has been analyzed and show that 32 percent of the surface is covered with white caps, foam and streaks. This result is in good agreement with a semi-empirical relationship incorporating both the wind speed and the local wave spectrum which predicts 26 percent white water for the conditions observed.

  7. Direct in situ observation of ZnO nucleation and growth via transmission X-ray microscopy.

    PubMed

    Tay, S E R; Goode, A E; Nelson Weker, J; Cruickshank, A A; Heutz, S; Porter, A E; Ryan, M P; Toney, M F

    2016-01-28

    The nucleation and growth of a nanostructure controls its size and morphology, and ultimately its functional properties. Hence it is crucial to investigate growth mechanisms under relevant growth conditions at the nanometer length scale. Here we image the nucleation and growth of electrodeposited ZnO nanostructures in situ, using a transmission X-ray microscope and specially designed electrochemical cell. We show that this imaging technique leads to new insights into the nucleation and growth mechanisms in electrodeposited ZnO including direct, in situ observations of instantaneous versus delayed nucleation. PMID:26738407

  8. Ionospheric simulation compared with Dynamics Explorer observations for November 22, 1981

    SciTech Connect

    Sojka, J.J.; Bowline, M.; Schunk, R.W. ); Craven, J.D.; Frank, L.A. ); Sharber, J.R.; Winningham, J.D. ); Brace, L.H. )

    1992-02-01

    Dynamics Explorer (DE) 2 electric field and particle data have been used to constrain the inputs of a time-dependent ionospheric model (TDIM) for a simulation of the ionosphere on November 22, 1981. The simulated densities have then been critically compared with the DE 2 electron density observations. This comparison uncovers a model-data disagreement in the morning sector trough, generally good agreement of the background density in the polar cap and evening sector trough, and a difficulty in modeling the observed polar F layer patches. From this comparison, the consequences of structure in the electric field and precipitation inputs can be seen. This is further highlighted during a substorm period for which DE 1 auroral images were available. Using these images, a revised dynamic particle precipitation pattern was used in the ionospheric model; the resulting densities were different from the original simulation. With this revised dynamic precipitation model, improved density agreement is obtained in the auroral/polar regions where the plasma convection is not stagnant. However, the dynamic study also reveals a difficulty of matching dynamic plasma convection is not stagnant. However, the dynamic study also reveals a difficulty of matching dynamic auroral patterns with static empirical convection patterns. In this case, the matching of the models produced intense auroral precipitation in a stagnation region, which, in turn, led to exceedingly large TDIM densities.

  9. Comparing the model-simulated global warming signal to observations using empirical estimates of unforced noise

    PubMed Central

    Brown, Patrick T.; Li, Wenhong; Cordero, Eugene C.; Mauget, Steven A.

    2015-01-01

    The comparison of observed global mean surface air temperature (GMT) change to the mean change simulated by climate models has received much public and scientific attention. For a given global warming signal produced by a climate model ensemble, there exists an envelope of GMT values representing the range of possible unforced states of the climate system (the Envelope of Unforced Noise; EUN). Typically, the EUN is derived from climate models themselves, but climate models might not accurately simulate the correct characteristics of unforced GMT variability. Here, we simulate a new, empirical, EUN that is based on instrumental and reconstructed surface temperature records. We compare the forced GMT signal produced by climate models to observations while noting the range of GMT values provided by the empirical EUN. We find that the empirical EUN is wide enough so that the interdecadal variability in the rate of global warming over the 20th century does not necessarily require corresponding variability in the rate-of-increase of the forced signal. The empirical EUN also indicates that the reduced GMT warming over the past decade or so is still consistent with a middle emission scenario's forced signal, but is likely inconsistent with the steepest emission scenario's forced signal. PMID:25898351

  10. COMPARING THE OBSERVABLE PROPERTIES OF DWARF GALAXIES ON AND OFF THE ANDROMEDA PLANE

    SciTech Connect

    Collins, Michelle L. M.; Martin, Nicolas F.; Rich, R. M.; Ibata, Rodrigo A.; Chapman, Scott C.; McConnachie, Alan W.; Ferguson, Annette M.; Irwin, Michael J.; Lewis, Geraint F.

    2015-01-20

    The thin, extended planes of satellite galaxies detected around both the Milky Way and Andromeda are not a natural prediction of the Λ-cold dark matter paradigm. Galaxies in these distinct planes may have formed and evolved in a different way (e.g., tidally) from their off-plane neighbors. If this were the case, one would expect the on- and off-plane dwarf galaxies in Andromeda to have experienced different evolutionary histories, which should be reflected by the chemistries, dynamics, and star formation histories of the two populations. In this work, we present new, robust kinematic observations for two on-plane M31 dwarf spheroidal galaxies (And XVI and XVII) and compile and compare all available observational metrics for the on- and off-plane dwarfs to search for a signal that would corroborate such a hypothesis. We find that, barring their spatial alignment, the on- and off-plane Andromeda dwarf galaxies are indistinguishable from one another, arguing against vastly different formative and evolutionary histories for these two populations.

  11. The highs and lows of cloud radiative feedback: Comparing observational data and CMIP5 models

    NASA Astrophysics Data System (ADS)

    Jenney, A.; Randall, D. A.

    2014-12-01

    Clouds play a complex role in the climate system, and remain one of the more difficult aspects of the future climate to predict. Over subtropical eastern ocean basins, particularly next to California, Peru, and Southwest Africa, low marine stratocumulus clouds (MSC) help to reduce the amount of solar radiation that reaches the surface by reflecting incident sunlight. The climate feedback associated with these clouds is thought to be positive. This project looks at CMIP5 models and compares them to observational data from CERES and ERA-Interim to try and find observational evidence and model agreement for low, marine stratocumulus cloud feedback. Although current evidence suggests that the low cloud feedback is positive (IPCC, 2014), an analysis of the simulated relationship between July lower tropospheric stability (LTS) and shortwave cloud forcing in MSC regions suggests that this feedback is not due to changes in LTS. IPCC, 2013: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1535 pp.

  12. Comparing the model-simulated global warming signal to observations using empirical estimates of unforced noise.

    PubMed

    Brown, Patrick T; Li, Wenhong; Cordero, Eugene C; Mauget, Steven A

    2015-01-01

    The comparison of observed global mean surface air temperature (GMT) change to the mean change simulated by climate models has received much public and scientific attention. For a given global warming signal produced by a climate model ensemble, there exists an envelope of GMT values representing the range of possible unforced states of the climate system (the Envelope of Unforced Noise; EUN). Typically, the EUN is derived from climate models themselves, but climate models might not accurately simulate the correct characteristics of unforced GMT variability. Here, we simulate a new, empirical, EUN that is based on instrumental and reconstructed surface temperature records. We compare the forced GMT signal produced by climate models to observations while noting the range of GMT values provided by the empirical EUN. We find that the empirical EUN is wide enough so that the interdecadal variability in the rate of global warming over the 20(th) century does not necessarily require corresponding variability in the rate-of-increase of the forced signal. The empirical EUN also indicates that the reduced GMT warming over the past decade or so is still consistent with a middle emission scenario's forced signal, but is likely inconsistent with the steepest emission scenario's forced signal. PMID:25898351

  13. Assessing evapotranspiration variability in contiguous United States: Comparing the various remote-sensed observations

    NASA Astrophysics Data System (ADS)

    Cai, X.; Zeng, R.

    2015-12-01

    Evapotranspiration (ET) couples the water cycle and energy budget of hydrological processes. Understanding the components of ET variability and their spatial distribution is essential for improving hydrological simulations, quantifying ET observation uncertainties and supporting water resources management under climate change. Although advances in monitoring hydrological components have been made, how to use various existing observations to obtain a better knowledge about ET variability remains a challenging task. This study adopts a system approach to analyze ET variability in contiguous United States, considering the factors of climatic forcing fluctuations and catchment storage dynamics. We apply an ET variance decomposition framework (Zeng and Cai, 2015) to calculate monthly ET variance based on climatic forcing (i.e., precipitation and potential ET) and GRACE terrestrial storage change data. We quantify the various sources of ET variance, in terms of variances of precipitation, potential ET and terrestrial storage and their covariances, and obtain a spatial map of its primary and secondary controlling factors in the in contiguous United States. Furthermore, the estimated ET variance is compared to two existing ET products (e.g., MODIS-based remote sensing and FLUEXNET-based interpolation). It is found that FLUXNET-based interpolation is systematically smaller than the estimated ET variance with less deviation; while the MODIS-based ET agrees with estimated ET variance with larger uncertainty. The decomposition framework provides not only an independent estimation of ET variance but also a method to assess the uncertainty of existing ET products.

  14. Comparing the Observable Properties of Dwarf Galaxies on and off the Andromeda Plane

    NASA Astrophysics Data System (ADS)

    Collins, Michelle L. M.; Martin, Nicolas F.; Rich, R. M.; Ibata, Rodrigo A.; Chapman, Scott C.; McConnachie, Alan W.; Ferguson, Annette M.; Irwin, Michael J.; Lewis, Geraint F.

    2015-01-01

    The thin, extended planes of satellite galaxies detected around both the Milky Way and Andromeda are not a natural prediction of the Λ-cold dark matter paradigm. Galaxies in these distinct planes may have formed and evolved in a different way (e.g., tidally) from their off-plane neighbors. If this were the case, one would expect the on- and off-plane dwarf galaxies in Andromeda to have experienced different evolutionary histories, which should be reflected by the chemistries, dynamics, and star formation histories of the two populations. In this work, we present new, robust kinematic observations for two on-plane M31 dwarf spheroidal galaxies (And XVI and XVII) and compile and compare all available observational metrics for the on- and off-plane dwarfs to search for a signal that would corroborate such a hypothesis. We find that, barring their spatial alignment, the on- and off-plane Andromeda dwarf galaxies are indistinguishable from one another, arguing against vastly different formative and evolutionary histories for these two populations.

  15. Comparing Loop Cross Sections Observed with Hi-C and AIA/SDO

    NASA Astrophysics Data System (ADS)

    Klimchuk, James A.; DeForest, Craig

    2016-05-01

    Many studies have reported coronal loop widths measured with AIA/SDO, TRACE, and other data. For warm loops (T ~ 1 MK), the characteristic diameter is about 1500 km. Sub-structure is likely to exist on smaller scales, but the envelope of the "strands" has this typical size. Since 1500 km (2 arcsec) is not large compared to the spatial resolution of the observations, there remained a question about whether the loops are actually much thinner. To address this concern, we have measured the widths of several loops observed at 193 A by both AIA and the Hi-C rocket experiment. Hi-C has 3-6 times better spatial resolution, so if the loops are substantially unresolved by AIA, it should be readily apparent. We find that the measured widths are very similar. Small differences (< 25%) are explainable by uncertainties in the point spread functions. We conclude that previous measurements of loop widths made by AIA and TRACE are essentially correct. We also find little evidence for loop sub-structure at the resolution of Hi-C. The individual strands that comprise loops are therefore smaller than 200 km. These results have important implications for coronal heating.

  16. Io's Volcanism: Thermo-Physical Models of Silicate Lava Compared with Observations of Thermal Emission

    NASA Technical Reports Server (NTRS)

    Davies, Ashely G.

    1996-01-01

    Analyses of thermal infrared outbursts from the jovian satellite Io indicate that at least some of these volcanic events are due to silicate lava. Analysis of the January 9, 1990 outburst indicates that this was an active eruption consisting of a large lava flow (with mass eruption rate of order 10(exp 5) cubic m/sec) and a sustained area at silicate liquidus temperatures. This is interpreted as a series of fire fountains along a rift zone. A possible alternative scenario is that of an overflowing lava lake with extensive fire fountaining. The January 9, 1990 event is unique as multispectral observations with respect to time were obtained. In this paper, a model is presented for the thermal energy lost by active and cooling silicate lava flows and lakes on Io. The model thermal emission is compared with Earth-based observations and Voyager IRIS data. The model (a) provides an explanation of the thermal anomalies on Io's surface; (b) provides constraints on flow behavior and extent and infers some flow parameters; and (c) determines flow geometry and change in flow size with time, and the temperature of each part of the flow or lava lake surface as a function of its age. Models of heat output from active lava flows or inactive but recently emplaced lava flows or overturning lava lakes alone are unable to reproduce the observations. If the January 9, 1990 event is the emplacement of a lava flow, the equivalent of 27 such events per year would yield a volume of material sufficient, if uniformly distributed, to resurface all of Io at a rate of 1 cm/year.

  17. Observations of the intraseasonal oscillations over two Brazilian low latitude stations: A comparative study

    NASA Astrophysics Data System (ADS)

    Guharay, A.; Batista, P. P.; Clemesha, B. R.; Buriti, R. A.

    2014-12-01

    A comparative study of intraseasonal oscillations (ISO) in the period range 20-110 days is carried out in the mesosphere and lower thermosphere (MLT) zonal wind at two low latitude stations, Cariri (7.4°S, 36.5°W) and Cachoeira Paulista (22.7°S, 45°W) located far from the convective anomaly region. Considerable seasonal and interannual variability is observed. The ISO in the MLT and lower atmosphere are found to be well correlated during winter and spring indicating a coupling of the atmospheric regions through the ISO. On the other hand, relatively less correlation during summer and fall may suggest a dominance of the in situ excitation of the ISO in the MLT relative to the lower atmospheric contribution. The correlation between the MLT and lower atmosphere is found to be a little higher at Cachoeira Paulista than Cariri. The ISO in the MLT shows good correlation between the two stations, but correlation is insignificant in the case of lower atmosphere. The ISO is most prominent in the upper troposphere, upper stratosphere and MLT. The waves responsible for communicating the ISO signature from the troposphere to the middle atmosphere in the tropics are believed to refract through mid-latitudes in course of their propagation. An evident height variation of the high amplitude ISO in the upper troposphere is observed with a clear annual oscillation at Cariri. The observed behaviors of the ISO at the present sites are discussed in the light of plausible physical mechanisms.

  18. Potential for observing and discriminating impact craters and comparable volcanic landforms on Magellan radar images

    NASA Astrophysics Data System (ADS)

    Ford, J. P.

    Observations of small terrestrial craters by Seasat synthetic aperture radar (SAR) at high resolution (approx. 25 m) and of comparatively large Venusian craters by Venera 15/16 images at low resolution (1000 to 2000 m) and shorter wavelength show similarities in the radar responses to crater morphology. At low incidence angles, the responses are dominated by large scale slope effects on the order of meters; consequently it is difficult to locate the precise position of crater rims on the images. Abrupt contrasts in radar response to changing slope (hence incidence angle) across a crater produce sharp tonal boundaries normal to the illumination. Crater morphology that is radially symmetrical appears on images to have bilateral symmetry parallel to the illumination vector. Craters are compressed in the distal sector and drawn out in the proximal sector. At higher incidence angles obtained with the viewing geometry of SIR-A, crater morphology appears less compressed on the images. At any radar incidence angle, the distortion of a crater outline is minimal across the medial sector, in a direction normal to the illumination. Radar bright halos surround some craters imaged by SIR-A and Venera 15 and 16. The brightness probably denotes the radar response to small scale surface roughness of the surrounding ejecta blankets. Similarities in the radar responses of small terrestrial impact craters and volcanic craters of comparable dimensions emphasize the difficulties in discriminating an impact origin from a volcanic origin in the images. Similar difficulties will probably apply in discriminating the origin of small Venusian craters, if they exist. Because of orbital considerations, the nominal incidence angel of Magellan radar at the center of the imaging swath will vary from about 45 deg at 10 deg N latitude to about 16 deg at the north pole and at 70 deg S latitude. Impact craters and comparable volcanic landforms will show bilateral symmetry parallel to the illumination

  19. Potential for observing and discriminating impact craters and comparable volcanic landforms on Magellan radar images

    NASA Technical Reports Server (NTRS)

    Ford, J. P.

    1989-01-01

    Observations of small terrestrial craters by Seasat synthetic aperture radar (SAR) at high resolution (approx. 25 m) and of comparatively large Venusian craters by Venera 15/16 images at low resolution (1000 to 2000 m) and shorter wavelength show similarities in the radar responses to crater morphology. At low incidence angles, the responses are dominated by large scale slope effects on the order of meters; consequently it is difficult to locate the precise position of crater rims on the images. Abrupt contrasts in radar response to changing slope (hence incidence angle) across a crater produce sharp tonal boundaries normal to the illumination. Crater morphology that is radially symmetrical appears on images to have bilateral symmetry parallel to the illumination vector. Craters are compressed in the distal sector and drawn out in the proximal sector. At higher incidence angles obtained with the viewing geometry of SIR-A, crater morphology appears less compressed on the images. At any radar incidence angle, the distortion of a crater outline is minimal across the medial sector, in a direction normal to the illumination. Radar bright halos surround some craters imaged by SIR-A and Venera 15 and 16. The brightness probably denotes the radar response to small scale surface roughness of the surrounding ejecta blankets. Similarities in the radar responses of small terrestrial impact craters and volcanic craters of comparable dimensions emphasize the difficulties in discriminating an impact origin from a volcanic origin in the images. Similar difficulties will probably apply in discriminating the origin of small Venusian craters, if they exist. Because of orbital considerations, the nominal incidence angel of Magellan radar at the center of the imaging swath will vary from about 45 deg at 10 deg N latitude to about 16 deg at the north pole and at 70 deg S latitude. Impact craters and comparable volcanic landforms will show bilateral symmetry parallel to the illumination

  20. Seeded growth of ferrite nanoparticles from Mn oxides: observation of anomalies in magnetic transitions.

    PubMed

    Song, Hyon-Min; Zink, Jeffrey I; Khashab, Niveen M

    2015-07-28

    A series of magnetically active ferrite nanoparticles (NPs) are prepared by using Mn oxide NPs as seeds. A Verwey transition is identified in Fe3O4 NPs with an average diameter of 14.5 nm at 96 K, where a sharp drop of magnetic susceptibility occurs. In MnFe2O4 NPs, a spin glass-like state is observed with the decrease in magnetization below the blocking temperature due to the disordered spins during the freezing process. From these MnFe2O4 NPs, MnFe2O4@Mn(x)Fe(1-x)O core-shell NPs are prepared by seeded growth. The structure of the core is cubic spinel (Fd3¯m), and the shell is composed of iron-manganese oxide (Mn(x)Fe(1-x)O) with a rock salt structure (Fm3¯m). Moiré fringes appear perpendicular to the 〈110〉 directions on the cubic shape NPs through the plane-matched epitaxial growth. These fringes are due to the difference in the lattice spacings between MnFe2O4 and Mn(x)Fe(1-x)O. Exchange bias is observed in these MnFe2O4@Mn(x)Fe(1-x)O core-shell NPs with an enhanced coercivity, as well as the shift of hysteresis along the field direction. PMID:26123580

  1. Direct in situ observation of ZnO nucleation and growth via transmission X-ray microscopy

    NASA Astrophysics Data System (ADS)

    Tay, S. E. R.; Goode, A. E.; Nelson Weker, J.; Cruickshank, A. A.; Heutz, S.; Porter, A. E.; Ryan, M. P.; Toney, M. F.

    2016-01-01

    The nucleation and growth of a nanostructure controls its size and morphology, and ultimately its functional properties. Hence it is crucial to investigate growth mechanisms under relevant growth conditions at the nanometer length scale. Here we image the nucleation and growth of electrodeposited ZnO nanostructures in situ, using a transmission X-ray microscope and specially designed electrochemical cell. We show that this imaging technique leads to new insights into the nucleation and growth mechanisms in electrodeposited ZnO including direct, in situ observations of instantaneous versus delayed nucleation.The nucleation and growth of a nanostructure controls its size and morphology, and ultimately its functional properties. Hence it is crucial to investigate growth mechanisms under relevant growth conditions at the nanometer length scale. Here we image the nucleation and growth of electrodeposited ZnO nanostructures in situ, using a transmission X-ray microscope and specially designed electrochemical cell. We show that this imaging technique leads to new insights into the nucleation and growth mechanisms in electrodeposited ZnO including direct, in situ observations of instantaneous versus delayed nucleation. Electronic supplementary information (ESI) available: Methods and videos of nanoparticle growth. See DOI: 10.1039/c5nr07019h

  2. Comparative CO/CO2 Production in NEOWISE-Observed Comets

    NASA Astrophysics Data System (ADS)

    Bauer, James M.; Stevenson, Rachel; Kramer, Emily; Grav, Tommy; Mainzer, A.; Masiero, Joseph; Cutri, Roc; Dailey, John; Sonnett, Sarah; Nugent, Carolyn; Meech, Karen; Walker, Russ; Lisse, Carey; Waszczak, Adam; Lucas, Andrew; Blair, Nathan; Wright, Edward

    2014-11-01

    NEOWISE [1,2] is the NASA Planetary Division-funded mission that utilizes data from the Wide-Field Infrared Survey Explorer (WISE) spacecraft to detect and characterize moving objects. NEOWISE has provided a large statistical sampling of comets in various states of activity, containing a variety of types of comets. This data set provides a unique opportunity to discern the trends in their observable properties and compare the ensemble properties between comet types, and may allow us to discern subtypes. The WISE spacecraft has discovered 22 new cometary bodies and observed over 160 comets, yielding the largest sample of comets yet observed at thermal-IR wavelengths. This collection offers a diverse range of comet behavior including highly active and inactive bodies from both long period comet (LPC) and short period comet (SPC) populations. We have conducted analyses of the physical properties of the NEOWISE-observed comets. In particular, our analysis constrains the quantity and nature of the ejected coma dust for large particles, and provides estimates of the nucleus sizes and albedos, as well as the production rates and extent of the CO/CO2 gas species. WISE is sensitive to CO and CO2 emission lines that fall within the 4.6 micron band pass (W2), at 4.3 and 4.7 microns, respectively. The quantity of dust present is found from the signal in the three other bands, centered at 3.4, 12, & 22 microns, and the dust signal in W2 is deduced, such that excess signal in W2 can be identified. We find detectable signal excess in nearby comets ~1AU distance from the Sun, as well as those as distant as 4.5AU, and approximately a third of both LPCs and SPCs show 4.6 micron infrared excess in our data. We will discuss in depth the production rates for the CO/CO2 gas species derived from the entire sample of comets. Acknowledgements: This work was supported by NEOWISE, which is a project of JPL/CalTech, funded by the Planetary Science Division of NASAReferences: [1] Mainzer, A

  3. Observation of plasma instabilities related to dust particle growth mechanisms in electron cyclotron resonance plasmas

    SciTech Connect

    Drenik, A.; CNRS, LAPLACE, 31062 Toulouse Yuryev, P.; Clergereaux, R.; Margot, J.

    2013-10-15

    Instabilities are observed in the self-bias voltage measured on a probe immersed in microwave plasma excited at Electron Cyclotron Resonance (ECR). Observed in the MHz range, they were systematically measured in dust-free or dusty plasmas (obtained for different conditions of applied microwave powers and acetylene flow rates). Two characteristic frequencies, well described as lower hybrid oscillations, can be defined. The first one, in the 60–70 MHz range, appears as a sharp peak in the frequency spectra and is observed in every case. Attributed to ions, its position shift observed with the output power highlights that nucleation process takes place in the dusty plasma. Attributed to lower hybrid oscillation of powders, the second broad peak in the 10–20 MHz range leads to the characterization of dust particles growth mechanisms: in the same way as in capacitively coupled plasmas, accumulation of nucleus confined near the probe in the magnetic field followed by aggregation takes place. Then, the measure of electrical instabilities on the self-bias voltage allows characterizing the discharge as well as the chemical processes that take place in the magnetic field region and their kinetics.

  4. Growth of calcium-aluminum-rich inclusions by coagulation and fragmentation in a turbulent protoplanetary disk: Observations and simulations

    NASA Astrophysics Data System (ADS)

    Charnoz, Sébastien; Aléon, Jérôme; Chaumard, Noël; Baillié, Kévin; Taillifet, Esther

    2015-05-01

    Whereas it is generally accepted that calcium-aluminum-rich inclusions (CAIs) from chondritic meteorites formed in a hot environment in the solar protoplanetary disk, the conditions of their formation remain debated. Recent laboratory studies of CAIs have provided new kind of data: their size distributions. We report that size distributions of CAIs measured in laboratory from sections of carbonaceous chondrites have a power law size distribution with cumulative size exponent between -1.7 and -1.9, which translates into cumulative size exponent between -2.5 and -2.8 after correction for sectioning. To explain these observations, numerical simulations were run to explore the growth of CAIs from micrometer to centimeter sizes, in a hot and turbulent protoplanetary disk through the competition of coagulation and fragmentation. We show that the size distributions obtained in growth simulations are in agreement with CAIs size distributions in meteorites. We explain the CAI sharp cut-off of their size distribution at centimeter sizes as the direct result from the famous fragmentation barrier, provided that CAI fragment for impact velocities larger than 10 m/s. The growth/destruction timescales of millimeter- and centimeter-sized CAIs is inversely proportional to the local dust/gas ratio and is about 10 years at 1300 K and up to 104 years at 1670 K. This implies that the most refractory CAIs are expected to be smaller in size owing to their long growth timescale compared to less refractory CAIs. Conversely, the least refractory CAIs could have been recycled many times during the CAI production era which may have profound consequences for their radiometric age.

  5. Comparative analysis of growth characteristics of Sprague Dawley rats obtained from different sources

    PubMed Central

    Brower, Marcia; Grace, Martha; Kotz, Catherine M.

    2015-01-01

    Genetic background in animal models is an intrinsic research variable in biomedical research. Although inbred strains offer genetic uniformity, the outbred stocks, known for genetic variability are often used to develop animal models of human disease. The genetic variability is considered to be even higher when outbred stocks are obtained from different sources. In order to examine the degree of variability of an outbred stock obtained from various sources, Sprague Dawley (SD) rat lines obtained from two sources were evaluated for their growth characteristics. The SD rats from Charles River laboratories (CRL) and Harlan Laboratories (HAR) were monitored for weight gain from the age of 6 weeks to 24 weeks. Food intake was monitored between 13 and 24 weeks. Body composition, organ weights, tibial lengths and blood parameters were measured. There was no difference observed in food intake per 100 gram body weight at most of the time points. CRL rats showed higher body fat mass (49.6%), higher gross liver weights (22.2%), lower testicular weights (30.8%) and lower cholesterol levels (25.4%) than HAR rats. Phenotypic differences may be attributed to genetic heterogeneity of the SD outbred stock between the two sources and represent a significant research variable impacting studies especially related to metabolic diseases. Therefore, in order the minimize research variables for those studies where genetic diversity is not a basis for experimental design, the use of single source genetically uniform inbred animal models is highly recommended over the use of outbred stocks. PMID:26755919

  6. Comparative analysis of growth characteristics of Sprague Dawley rats obtained from different sources.

    PubMed

    Brower, Marcia; Grace, Martha; Kotz, Catherine M; Koya, Vijay

    2015-12-01

    Genetic background in animal models is an intrinsic research variable in biomedical research. Although inbred strains offer genetic uniformity, the outbred stocks, known for genetic variability are often used to develop animal models of human disease. The genetic variability is considered to be even higher when outbred stocks are obtained from different sources. In order to examine the degree of variability of an outbred stock obtained from various sources, Sprague Dawley (SD) rat lines obtained from two sources were evaluated for their growth characteristics. The SD rats from Charles River laboratories (CRL) and Harlan Laboratories (HAR) were monitored for weight gain from the age of 6 weeks to 24 weeks. Food intake was monitored between 13 and 24 weeks. Body composition, organ weights, tibial lengths and blood parameters were measured. There was no difference observed in food intake per 100 gram body weight at most of the time points. CRL rats showed higher body fat mass (49.6%), higher gross liver weights (22.2%), lower testicular weights (30.8%) and lower cholesterol levels (25.4%) than HAR rats. Phenotypic differences may be attributed to genetic heterogeneity of the SD outbred stock between the two sources and represent a significant research variable impacting studies especially related to metabolic diseases. Therefore, in order the minimize research variables for those studies where genetic diversity is not a basis for experimental design, the use of single source genetically uniform inbred animal models is highly recommended over the use of outbred stocks. PMID:26755919

  7. Comparative genomic analysis and phenazine production of Pseudomonas chlororaphis, a plant growth-promoting rhizobacterium.

    PubMed

    Chen, Yawen; Shen, Xuemei; Peng, Huasong; Hu, Hongbo; Wang, Wei; Zhang, Xuehong

    2015-06-01

    Pseudomonas chlororaphis HT66, a plant growth-promoting rhizobacterium that produces phenazine-1-carboxamide with high yield, was compared with three genomic sequenced P. chlororaphis strains, GP72, 30-84 and O6. The genome sizes of four strains vary from 6.66 to 7.30 Mb. Comparisons of predicted coding sequences indicated 4833 conserved genes in 5869-6455 protein-encoding genes. Phylogenetic analysis showed that the four strains are closely related to each other. Its competitive colonization indicates that P. chlororaphis can adapt well to its environment. No virulence or virulence-related factor was found in P. chlororaphis. All of the four strains could synthesize antimicrobial metabolites including different phenazines and insecticidal protein FitD. Some genes related to the regulation of phenazine biosynthesis were detected among the four strains. It was shown that P. chlororaphis is a safe PGPR in agricultural application and could also be used to produce some phenazine antibiotics with high-yield. PMID:26484173

  8. Comparative genomic analysis and phenazine production of Pseudomonas chlororaphis, a plant growth-promoting rhizobacterium

    PubMed Central

    Chen, Yawen; Shen, Xuemei; Peng, Huasong; Hu, Hongbo; Wang, Wei; Zhang, Xuehong

    2015-01-01

    Pseudomonas chlororaphis HT66, a plant growth-promoting rhizobacterium that produces phenazine-1-carboxamide with high yield, was compared with three genomic sequenced P. chlororaphis strains, GP72, 30–84 and O6. The genome sizes of four strains vary from 6.66 to 7.30 Mb. Comparisons of predicted coding sequences indicated 4833 conserved genes in 5869–6455 protein-encoding genes. Phylogenetic analysis showed that the four strains are closely related to each other. Its competitive colonization indicates that P. chlororaphis can adapt well to its environment. No virulence or virulence-related factor was found in P. chlororaphis. All of the four strains could synthesize antimicrobial metabolites including different phenazines and insecticidal protein FitD. Some genes related to the regulation of phenazine biosynthesis were detected among the four strains. It was shown that P. chlororaphis is a safe PGPR in agricultural application and could also be used to produce some phenazine antibiotics with high-yield. PMID:26484173

  9. Characteristics of formation and growth of atmospheric nanoparticles observed at four regional background sites in Korea

    NASA Astrophysics Data System (ADS)

    Kim, Yumi; Kim, Sang-Woo; Yoon, Soon-Chang; Park, Jin-Soo; Lim, Jae-Hyun; Hong, Jihyung; Lim, Han-Cheol; Ryu, Jegyu; Lee, Chul-Kyu; Heo, Bok-Haeng

    2016-02-01

    Measurements of the number concentration and size distribution of atmospheric nanoparticles were conducted at four sites on the west coast of the Korean Peninsula by using identical scanning mobility particle sizers (SMPSs) in October 2012. The new particle formation and subsequent growth (NPF) of atmospheric nanoparticles, which were identified by the cyclostationary empirical orthogonal function (CSEOF) analysis technique, was observed on 11 out of 21 days at the Baengnyeong-do Comprehensive Monitoring Observatory (BCMO); and on 10 out of 21 days at the Korea Global Atmosphere Watch Center (KGAWC) from October 9 to 29, 2012. We also observed NPF events for 9 out of 21 days at both the Gosan Climate Observatory (GCO) and the Jeju Comprehensive Monitoring Observatory (JCMO). During the study period, NPF was simultaneously observed for five days at all four sites, which indicates that the NPF event had a spatial extent of at least 540 km. A cold, dry and cloud-free continental air mass originated from northern China, formed favorable environmental conditions (e.g., increasing solar insolation at the surface) on simultaneous NPF at the four sites. These synoptic weather patterns were closely associated with an extraordinary typhoon passing over the south of Japan. The mean values of particle formation rates at BCMO (1.26 cm- 3 s- 1) and KGAWC (1.49 cm- 3 s- 1) were relatively higher than those at GCO (0.39 cm- 3 s- 1) and JCMO (0.74 cm- 3 s- 1), however, the growth rate showed a similar level among four sites. An increase in the spatial homogeneity and inter-site correlation of atmospheric particles among the four sites was apparent for small particles (diameter < 30 nm) on simultaneous NPF event days.

  10. Observations and modelling of fast ice growth in the Tiksi Bay, Laptev Sea

    NASA Astrophysics Data System (ADS)

    Bogorodsky, Petr; Makshtas, Aleksandr; Grubiy, Andrey; Kustov, Vasiliy

    2016-04-01

    Fast ice is one of the main features of sea ice cover in the Laptev Sea. The formation of this immobile ice which occupies up to 30% of the sea area and significantly affects the intensity of air-sea energy exchange in the coastal zones had been investigated during winter 2014-2015 in the Tiksi Bay (Buor-Khaya Gulf). The temperature measurements within sea ice thickness and under-ice sea layer using GeoPrecision thermistor string of 10 sensors together with measurements of snow and ice thicknesses were carried out at the distance of 0.5 km from the shore at the 3.5 m water depth. According to measurements temperature variations qualitatively repeat air temperature variations and, damping with depth, approach to sea water freezing temperature. Vertical temperature distributions allow to recognize snow, ice and water layers by profile inclination in each layer. The temperature profiles within growing ice were quasi-linear, indicating permanence of heat flux inside ice. The linearity of temperature profiles increased during ice growth. For calculations of fast ice evolution one-dimensional thermodynamic model was used. Besides the empirical formulae, based on frost degree-days, developed in 1930th for the Tiksi Bay was applied. Numerical experiments were carried out with constant values of thermal properties of all media and 10 ppt water salinity, as initial condition. The daily average data from Hydrometeorological Observatory Tiksi, located approximately 1 km from the site of ice observations, were used as atmospheric forcing. For the examined area evolutions of ice cover thickness estimated from direct measurements, the thermodynamic model and the empirical formulae were almost identical. The result indicates stability of hydrological and meteorological conditions, determining fast ice growth in the Tiksi Bay during last 75 years. Model simulations showed that in shallow waters the growth of ice thickness is stabilized due to increase of sub-ice water layer

  11. Comparing and contrasting observed adaptations in three deltas: the Ganges-Meghna-Brahmaputra, Mahanadi and Volta

    NASA Astrophysics Data System (ADS)

    Nicholls, R. J.; Suckall, N.; Mensah, A.; Mondal, S.; Dey, S.; Hazra, S.

    2015-12-01

    In low and middle-income countries, many deltaic communities directly depend on the natural environment for income and well-being. Current environmental concerns that threaten deltaic communities, such as increasing salinity, sedimentation, erosion and subsidence are likely to be exacerbated by climate change and variability, for example sea-level rise, increased storminess and rising temperatures. Such changes, along with other social and environmental stressors, mean that communities must adapt. This paper outlines findings of a systematic review of the peer-reviewed and grey literature that examines observed adaptations in three deltas of differing sizes in various geographical contexts: the Ganges-Meghna-Brahmaputra in India and Bangladesh, the Mahanadi in India, and the Volta in Ghana. It compares and contrasts various elements of observed adaptations, including who is driving the adaptation, the beneficiaries, barriers to participation and evidence for maladaptation. The predominant drivers of adaptation vary from government (at state level in India and national level in Bangladesh) and NGOs (in Ghana). Autonomous adaptations are not widely reported in the literature from any of the deltas. In all three deltas there is a focus on supporting adaptation in farming rather than fishing; despite the fact that fisheries contribute to local food security as well as national economies. Lack of access to financial, natural, physical and human capital are common barriers to adaptation in all three deltas. Additionally the Indian literature in particular highlights the lack of coordination between different government departments, coupled with an excessively top-down (state-driven) approach to adaptation. Maladaptation is most commonly reported in the literature from Bangladesh, for example, loss of employment of inland fishermen in embanked areas. The paper concludes by highlighting some of the implications of these findings for adaptation policy in deltas.

  12. Comparing the relationships between aerosol optical depth and cloud properties in observations and global models

    NASA Astrophysics Data System (ADS)

    Gryspeerdt, Edward; Quaas, Johannes

    2016-04-01

    Aerosols impact the climate both directly, through their interaction with radiation and indirectly, via their ability to act as cloud condensation nuclei (CCN), modifying cloud properties. The influence of aerosols on cloud properties is highly uncertain. Many relationships between aerosol optical depth (AOD) and cloud properties have been observed using satellite data, but previous work has shown that some of these relationships are the product of the strong AOD-cloud fraction (CF) relationship. The confounding influence of local meteorology obscures the magnitude of any aerosol impact on CF, and so also the impact of aerosol on other cloud properties. For example, both AOD and CF are strongly influenced by relative humidity, which can generate a correlation between them. Previous studies have used reanalysis data to account for confounding meteorological variables. This requires knowledge of the relevant meteorological variables and is limited by the accuracy of the reanalysis data. Recent work has shown that by using the cloud droplet number concentration (CDNC) to mediate the AOD-CF relationship, the impact of relative humidity can be significantly reduced. This method removes the limitations imposed by the finite accuracy of reanalysis data. In this work we investigate the impact of the CDNC mediation on the AOD-CF relationship and on the relationship between AOD and other cloud properties in global atmospheric models. By comparing pre-industrial and present day runs, we investigate the success of the CDNC mediated AOD-CF relationship to predict the change in CF from the pre-industrial to the present day using only observations of the present day relationships between clouds and aerosol properties. This helps to determine whether the satellite-derived relationship provides a constraint on the aerosol indirect forcing due to changes in CF.

  13. Comparing observations and process-based simulations of biosphere-atmosphere exchanges on multiple timescales

    NASA Astrophysics Data System (ADS)

    Mahecha, M. D.; Reichstein, M.; Jung, M.; Seneviratne, S. I.; Zaehle, S.; Beer, C.; Braakhekke, M. C.; Carvalhais, N.; Lange, H.; Le Maire, G.; Moors, E.

    2010-06-01

    Terrestrial biosphere models are indispensable tools for analyzing the biosphere-atmosphere exchange of carbon and water. Evaluation of these models using site level observations scrutinizes our current understanding of biospheric responses to meteorological variables. Here we propose a novel model-data comparison strategy considering that CO2 and H2O exchanges fluctuate on a wide range of timescales. Decomposing simulated and observed time series into subsignals allows to quantify model performance as a function of frequency, and to localize model-data disagreement in time. This approach is illustrated using site level predictions from two models of different complexity, Organizing Carbon and Hydrology in Dynamic Ecosystems (ORCHIDEE) and Lund-Potsdam-Jena (LPJ), at four eddy covariance towers in different climates. Frequency-dependent errors reveal substantial model-data disagreement in seasonal-annual and high-frequency net CO2 fluxes. By localizing these errors in time we can trace these back, for example, to overestimations of seasonal-annual periodicities of ecosystem respiration during spring greenup and autumn in both models. In the same frequencies, systematic misrepresentations of CO2 uptake severely affect the performance of LPJ, which is a consequence of the parsimonious representation of phenology. ORCHIDEE shows pronounced model-data disagreements in the high-frequency fluctuations of evapotranspiration across the four sites. We highlight the advantages that our novel methodology offers for a rigorous model evaluation compared to classical model evaluation approaches. We propose that ongoing model development will benefit from considering model-data (dis)agreements in the time-frequency domain.

  14. A Comparative Study of Confined and Eruptive Solar Flares using Microwave Observations

    NASA Astrophysics Data System (ADS)

    Yashiro, S.; Akiyama, S.; Masuda, S.; Shimojo, M.; Asai, A.; Imada, S.; Gopalswamy, N.

    2015-12-01

    It is well known that about 10% X-class solar flares are not associated with coronal mass ejections (CMEs). These flares are referred to as confined flares, which are not associated with mass or energetic particles leaving the Sun. However, electrons are accelerated to MeV energies as indicated by the presence of microwave emission with a turnover frequency of ~15 GHz (Gopalswamy et al. 2009, IAU Symposium 257, p. 283). In this paper, we extend the study of confined flares to lower soft X-ray flare sizes (M and above) that occurred in the time window of the Nobeyama Radioheliograph (NoRH). We also make use of the microwave spectral information from the Nobeyama Radio Polarimeters (NoRP). During 1996 - 2014, NoRH and NoRP observed 663 flares with size M1.0 or larger. Using the CME observations made by SOHO/LASCO and STEREO/SECCHI, we found 215 flares with definite CME association (eruptive flares) and 202 flares that definitely lacked CMEs (confined flares). The remaining 146 flares whose CME association is unclear are excluded from the analysis. We examined the peak brightness temperature and the spatial size obtained by NoRH. Although there is a large overlap between the two populations in these properties, we found that microwave sources with the largest spatial extent and highest brightness temperature are associated with eruptive flares. Spectral analysis using NoRP data showed a tendency that more confined flares had higher turnover frequency (≥17 GHz). We also compare the NoRH images with the photospheric magnetograms to understand the difference in the magnetic structure of the two types of flare sources.

  15. Physician Associate and General Practitioner Consultations: A Comparative Observational Video Study

    PubMed Central

    de Lusignan, Simon; McGovern, Andrew P.; Tahir, Mohammad Aumran; Hassan, Simon; Jones, Simon; Halter, Mary; Joly, Louise; Drennan, Vari M.

    2016-01-01

    Background Physician associates, known internationally as physician assistants, are a mid-level practitioner, well established in the United States of America but new to the United Kingdom. A small number work in primary care under the supervision of general practitioners, where they most commonly see patients requesting same day appointments for new problems. As an adjunct to larger study, we investigated the quality of the patient consultation of physician associates in comparison to that of general practitioners. Method We conducted a comparative observational study using video recordings of consultations by volunteer physician associates and general practitioners with consenting patients in single surgery sessions. Recordings were assessed by experienced general practitioners, blinded to the type of the consulting practitioner, using the Leicester Assessment Package. Assessors were asked to comment on the safety of the recorded consultations and to attempt to identify the type of practitioner. Ratings were compared across practitioner type, alongside the number of presenting complaints discussed in each consultation and the number of these which were acute, minor, or regarding a chronic condition. Results We assessed 62 consultations (41 general practitioner and 21 physician associates) from five general practitioners and four physician associates. All consultations were assessed as safe; but general practitioners were rated higher than PAs in all elements of consultation. The general practitioners were more likely than physician associates to see people with multiple presenting complaints (p<0.0001) and with chronic disease related complaints (p = 0.008). Assessors correctly identified general practitioner consultations but not physician associates. The Leicester Assessment Package had limited inter-rater and intra-rater reliability. Conclusions The physician associate consultations were with a less complex patient group. They were judged as competent and safe

  16. Occluded and nonoccluded nuclear polyhedrosis virus grown in Trichoplusia ni: comparative neutralization comparative infectivity, and in vitro growth studies.

    PubMed Central

    Volkman, L E; Summers, M D; Hsieh, C H

    1976-01-01

    Nuclear polyhedrosis virus infections of lepidopteran cells often result in the production of both occluded and nonoccluded virus. The characterization of these two different forms has been the subject of several papers. We have divided the nonoccluded virus (NOV) category further into plasma membrane-budded non-occluded virus (PMB-NOV), intracellular NOV, and hemolymph-derived NOV, and have done additional studies investigating the differences between these nonoccluded forms and the alkali-liberated forms from occlusions of the nuclear polyhedrosis viruses of Autographa californica and Rachiplusa ou. The methods used to discern differences and similarities among the forms were serological, biochemical, and visual, all related to their biological acitivity. Neutralization studies revealed that alkali-liberated virus and PMB-NOV had both similar and different antigens. Antisera raised against alkali-liberated virus from occlusions neutralized the alkali-liberated form of the virus, but did not neutralize the intracellular or extracellular nonoccluded forms. Antisera raised against the TN-368-13 PMB-NOV, however, neutralized the alkali-liberated forms as well as all forms of the NOV. Adsorption of this antisera with alkali-liberated virus did not diminish the neutralization titer against the nonoccluded forms, thus confirming the antigenic differences between the alkali-liberated and nonoccluded forms of the virus. Physical-infectious particle ratio calculations indicated that the PMB-NOV of Autographa californica are about 1,900-fold more infectious than the single-nucleocapsid-per-envelope alkali-liberated particles and about 1,700-fold more infectious than the multiple-nucleocapsid-per-envelope particles, as assayed in vitro. In addition, a study of viral growth kinetics monitored concurrently with the appearance of polyhedra showed that PMB-NOV production is shut down with the onset of polyhedron formation. PMID:787558

  17. Comparing Stable Water Isotope Variation in Atmospheric Moisture Observed over Coastal Water and Forests

    NASA Astrophysics Data System (ADS)

    Lai, C. T.; Rambo, J. P.; Welp, L. R.; Bible, K.; Hollinger, D. Y.

    2014-12-01

    Stable oxygen (δ18O) and hydrogen (δD) isotopologues of atmospheric moisture are strongly influenced by large-scale synoptic weather cycles, surface evapotranspiration and boundary layer mixing. Atmospheric water isotope variation has been shown to empirically relate to relative humidity (Rh) of near surface moisture, and to a less degree, air temperature. Continuous δ18O and δD measurements are becoming more available, providing new opportunities to investigate processes that control isotope variability. This study shows the comparison of δ18O and δD measured at a continental location and over coastal waters for 3 seasons (spring to fall, 2014). The surface moisture isotope measurements were made using two LGR spectroscopy water vapor isotope analyzers (Los Gatos Research Inc.), one operated in an old-growth coniferous forest at Wind River field station, WA (45.8205°N, 121.9519°W), and another sampling marine air over seawater at the Scripps Pier in San Diego, CA (32.8654°N, 117.2536°W), USA. Isotope variations were measured at 1Hz and data were reported as hourly averages with an overall accuracy of ±0.1‰ for δ18O, ±0.5‰ for δ2H. Day-to-day variations in δ18O and δD are shown strongly influenced by synoptic weather events at both locations. Boundary layer mixing between surface moisture and the dry air entrained from the free troposphere exerts a midday maximum and a consistent diel pattern in deuterium excess (dx). At the forest site, surface moisture also interacts with leaf water through transpiration during the day and re-equilibration at night. The latter occurs by retro-diffusion of atmospheric H2O molecules into leaf intercellular space, which becomes intensified as Rh increaes after nightfall, and continues until sunrise, to counter-balance the evaporative isotopic enrichment in leaf water on a daily basis. These vegetation effects lead to negative dx values consistently observed at nighttime in this continental location that were not

  18. A Proxy System Modeling Toolbox for Comparing Water Isotope Observations to Simulations

    NASA Astrophysics Data System (ADS)

    Dee, S. G.; Emile-Geay, J.; Evans, M. N.; Noone, D. C.

    2014-12-01

    Simulations which integrate both climate physics and the processes by which climate variations are imprinted in and sampled from paleoclimate archives may facilitate differentiation of the climate signal from random and systematic sources of uncertainty. We simulate the former using a newly developed efficient water-isotope-enabled atmospheric GCM, SPEEDY-IER (Molteni, 2003, Dee et al., submitted), and the latter using a toolbox of proxy system models (PSMs, Evans et al., 2013), synthesized, organized and coded within a self-consistent framework (Dee et al., in prep). SPEEDY-IER is forced with SSTs from the Last Millennium PMIP3 integration of the CCSM4 model (Landrum et al., 2012); relevant climate and isotope variables are extracted from the GCM simulation and used to drive PSMs. Through comparing simulated climate fields to simulated observations, we evaluate the extent to which linear and univariate calibrations on local temperature are valid, given bias in the simulated SST, moisture divergence, and associated isotopic composition of water vapor and precipitation. Taking this a step further, PSMs that incorporate the physical, biological, structural, and time-uncertain aspects of each proxy system help to explicitly quantify the errors accompanying the assumption of linear univariate response of proxy systems to climate forcing. We demonstrate the utility of the PSM toolbox with an integrative multi-PSM simulation spanning a realistic pan-tropical pacific proxy network of tree-ring cellulose, speleothem, and ice core oxygen isotopic composition (δ18O). The multi-PSM simulation is used as a testing ground to assess the robustness of frequently invoked teleconnections relating tropical SSTs to terrestrial hydroclimate proxies. By exploring modeled connections between ocean climate and the proxies (both by individual proxy class and for the entire network), we identify which tropical SST signals can be captured by the proxy network, track the individual

  19. Constraints from Cosmological Data on Expansion and Growth of Structure Observables in a Macroscopic Gravity Averaged Universe

    NASA Astrophysics Data System (ADS)

    Ishak-Boushaki, Mustapha B.; Wijenayake, Tharake

    2016-06-01

    We report recent results from investigating the effect of averaging inhomogeneities on cosmological distances and large-scale structure growth observables using the exact and covariant framework of Macroscopic Gravity (MG) averaging. For the MG formalism applied to the Friedmann-Lemaitre-Robertson-Walker (FLRW) metric, this gives an extra dynamical term encapsulated as an averaging density parameter denoted ΩA. We analyze constraints on this parameter and its correlations with other cosmological parameters from using the CMB (Planck), distances to supernovae, Baryon Acoustic Oscillations, Hubble constant measurements, and the CFHTLenS and other recent data. We compare the amplitude of this effect to other systematic effects considered for future high precision surveys.

  20. A Field Guide to Extra-Tropical Cyclones: Comparing Models to Observations

    NASA Astrophysics Data System (ADS)

    Bauer, M.

    2008-12-01

    Climate it is said is the accumulation of weather. And weather is not the concern of climate models. Justification for this latter sentiment has long hidden behind coarse model resolutions and blunt validation tools based on climatological maps and the like. The spatial-temporal resolutions of today's models and observations are converging onto meteorological scales however, which means that with the correct tools we can test the largely unproven assumption that climate model weather is correct enough, or at least lacks perverting biases, such that its accumulation does in fact result in a robust climate prediction. Towards this effort we introduce a new tool for extracting detailed cyclone statistics from climate model output. These include the usual cyclone distribution statistics (maps, histograms), but also adaptive cyclone- centric composites. We have also created a complementary dataset, The MAP Climatology of Mid-latitude Storminess (MCMS), which provides a detailed 6 hourly assessment of the areas under the influence of mid- latitude cyclones based on Reanalysis products. Using this we then extract complimentary composites from sources such as ISCCP and GPCP to create a large comparative dataset for climate model validation. A demonstration of the potential usefulness of these tools will be shown. dime.giss.nasa.gov/mcms/mcms.html

  1. Growth responses following a single intra-muscular hGH plasmid administration compared to daily injections of hGH in dwarf mice.

    PubMed

    Higuti, Eliza; Cecchi, Claudia R; Oliveira, Nelio A J; Vieira, Daniel P; Jensen, Thomas G; Jorge, Alexander A L; Bartolini, Paolo; Peroni, Cibele N

    2012-12-01

    In previous work, sustained levels of circulating human growth hormone (hGH) and a highly significant weight increase were observed after electrotransfer of naked plasmid DNA (hGH-DNA) into the muscle of immunodeficient dwarf mice (lit/scid). In the present study, the efficacy of this in vivo gene therapy strategy is compared to daily injections (5 μg/twice a day) of recombinant hGH (r-hGH) protein, as assessed on the basis of several growth parameters. The slopes of the two growth curves were found to be similar (P > 0.05): 0.095 g/mouse/d for protein and 0.094 g/mouse/d for DNA injection. In contrast, the weight increases averaged 35.5% (P < 0.001) and 23.1% (P < 0.01) for protein and DNA administration, respectively, a difference possibly related to the electroporation methodology. The nose-to-tail linear growth increases were 15% and 9.6% for the protein and DNA treatments, respectively, but mouse insulin-like growth factor I (mIGF-I) showed a greater increase over the control with DNA (5- to 7-fold) than with protein (3- to 4-fold) administration. The weight increases of several organs and tissues (kidneys, spleen, liver, heart, quadriceps and gastrocnemius muscles) were 1.3- to 4.6-fold greater for protein than for DNA administration, which gave a generally more proportional growth. Glucose levels were apparently unaffected, suggesting the absence of effects on glucose tolerance. A gene transfer strategy based on a single hGH-DNA administration thus appears to be comparable to repeated hormone injections for promoting growth and may represent a feasible alternative for the treatment of growth hormone deficiency. PMID:22974419

  2. Comparing inversion techniques for constraining CO2 fluxes in the Brazilian Amazon Basin with aircraft observations

    NASA Astrophysics Data System (ADS)

    Chow, V. Y.; Gerbig, C.; Longo, M.; Koch, F.; Nehrkorn, T.; Eluszkiewicz, J.; Ceballos, J. C.; Longo, K.; Wofsy, S. C.

    2012-12-01

    aircraft mixing ratios are applied as a top down constraint in Maximum Likelihood Estimation (MLE) and Bayesian inversion frameworks that solves for parameters controlling the flux. Posterior parameter estimates are used to estimate the carbon budget of the BAB. Preliminary results show that the STILT-VPRM model simulates the net emission of CO2 during both transition periods reasonably well. There is significant enhancement from biomass burning during the November 2008 profiles and some from fossil fuel combustion during the May 2009 flights. ΔCO/ΔCO2 emission ratios are used in combination with continuous observations of CO to remove the CO2 contributions from biomass burning and fossil fuel combustion from the observed CO2 measurements resulting in better agreement of observed and modeled aircraft data. Comparing column calculations for each of the vertical profiles shows our model represents the variability in the diurnal cycle. The high altitude CO2 values from above 3500m are similar to the lateral boundary conditions from CarbonTracker 2010 and GEOS-Chem indicating little influence from surface fluxes at these levels. The MLE inversion provides scaling factors for GEE and R for each of the 8 vegetation types and a Bayesian inversion is being conducted. Our initial inversion results suggest the BAB represents a small net source of CO2 during both of the BARCA intensives.

  3. Issues and trends in pediatric growth hormone therapy--an update from the GHMonitor observational registry.

    PubMed

    Pitukcheewanont, Pisit; Desrosiers, Paul; Steelman, Joel; Rapaport, Robert; Fuqua, John S; Kreher, Nerissa C; Hamlett, Anthony

    2008-02-01

    The GHMonitor observational registry collates data on pediatric subjects receiving Saizen (recombinant human growth hormone (GH)) therapy. From January 2003 through August 2006, 1335 subjects were enrolled in the registry, approximately two-thirds of whom are male. The most common diagnosis in the registry is idiopathic growth hormone deficiency (58%). Most subjects in GHMonitor are receiving Saizen doses using a needle-free delivery device, the cool.click (73%). Mean height standard deviation scores show an improvement from -2.1 at screening to -1.1 following 3 years of Saizen therapy. To date, adverse events have been reported in 4% of subjects. Three serious adverse events were identified to be related to Saizen by the primary investigator: cellulitis at the injection site, behavioral problems/suicidal ideation, and enlargement of a craniopharyngioma. This article provides an update on data from the registry and briefly discusses topical and controversial issues in the treatment of pediatric patients requiring GH therapy. PMID:18317441

  4. Connecting Observations of Hematite (a Fe2O3) Growth Catalyzed by Fe(II)

    SciTech Connect

    Rosso, Kevin M.; Yanina, Svetlana; Gorski, Christopher A.; Larese-Casanova, Philip; Scherer, Michelle

    2010-01-14

    Electron exchange between aqueous Fe(II) and structural Fe(III) in iron oxides and oxyhydroxides is important for understanding degradation of environmental pollutants through its apparent constitutive role underlying highly reactive “sorbed Fe(II)” and by catalyzing phase interconversion among these minerals. Although a mechanistic understanding of relationships between interfacial Fe(II)ads-Fe(III)oxide electron transfer, bulk electron conduction, and phase transformation behavior is emerging, much remains unclear in part due to poorly interconnected investigations. The focus of this study is on reconciling two mutually similar observations of Fe(II)-catalyzed hematite growth documented spectroscopically and microscopically under substantially different chemical conditions. Here we employ iron isotopic labeling to demonstrate that hematite grown on the (001) surface in Fe(II)-oxalate solution at low pH and elevated temperature has temperature-dependent magnetic properties that closely correspond to those of hematite grown in Fe(II) solution at circumneutral pH at room temperature. The temperature evolution and extent of the Morin transition displayed in these two materials strongly suggest a mechanistic link between the two studies, and that this mechanism involves in part trace structural Fe(II) incorporation into the growing hematite. Our findings indicate that Fe(II) catalyzed growth of hematite on hematite can occur under environmentally relevant conditions and may be due to bulk electron conduction previously demonstrated for hematite single crystals.

  5. Direct time-resolved observation of tungsten nanostructured growth due to helium plasma exposure

    NASA Astrophysics Data System (ADS)

    Fiflis, P.; Curreli, D.; Ruzic, D. N.

    2015-03-01

    Determination of the mechanisms underlying the growth of tungsten fuzz is an important step towards mitigation of fuzz formation. Nanostructured tungsten was produced on resistively heated tungsten wires in a helicon plasma source (maximum flux of 2.5 × 1021 m-2 s-1). Asymmetry in the setup allows for investigation of temperature and flux effects in a single sample. An effort at elucidating the mechanism of formation was made by inspecting SEM micrographs of the nanostructured tungsten at successive fluence steps of helium ions up to a fluence of 1 × 1027 m-2. To create these micrographs a single tungsten sample was exposed to the plasma, removed and inspected with an SEM, and replaced into the plasma. The tungsten surface was marked in several locations so that each micrograph is centred within 200 nm of each previous micrograph. Pitting of the surface (diameter 9.5 ± 2.3 nm, fluence (5 ± 2) × 1025 m-2) followed by surface roughening (fluence (9 ± 2) × 1025 m-2) and tendril formation (diameter 30 ± 10 nm, fluence (2 ± 1) × 1026 m-2) is observed, providing evidence of bubble bursting as the mechanism for seeding the growth of the tungsten fuzz.

  6. Preschool Children's Explanations of Plant Growth and Rain Formation: A Comparative Analysis

    ERIC Educational Resources Information Center

    Christidou, Vasilia; Hatzinikita, Vassilia

    2006-01-01

    This paper explores the different types and characteristics of preschool children's explanations of plant growth and rain formation. The children's explanations were categorized as naturalistic, non-naturalistic, or synthetic, i.e., explanations containing both naturalistic and non-naturalistic parts. In regards to plant growth the children…

  7. Comparing Student Performance and Growth in 2- and 4-Year Institutions.

    ERIC Educational Resources Information Center

    Strauss, Linda C.; Volkwein, J. Fredericks

    2002-01-01

    Examined the organizational characteristics of 51 higher education institutions in relationship to student performance and growth. Findings included that the different 2-year and 4-year campus missions do exert significantly different influences on undergraduate GPA and self-reported intellectual growth, with students at 2-year institutions…

  8. Growth Rate of Cosmological Perturbations at z∼0.1 from a New Observational Test.

    PubMed

    Feix, Martin; Nusser, Adi; Branchini, Enzo

    2015-07-01

    Spatial variations in the distribution of galaxy luminosities, estimated from redshifts as distance proxies, are correlated with the peculiar velocity field. Comparing these variations with the peculiar velocities inferred from galaxy redshift surveys is a powerful test of gravity and dark-energy theories on cosmological scales. Using ∼2×10(5) galaxies from the SDSS Data Release 7, we perform this test in the framework of gravitational instability to estimate the normalized growth rate of density perturbations fσ8=0.37±0.13 at z∼0.1, which is in agreement with the cold dark matter model with a cosmological constant. This unique measurement is complementary to those obtained with more traditional methods, including clustering analysis. The estimated accuracy at z∼0.1 is competitive with other methods when applied to similar data sets. PMID:26182087

  9. Growth Rate of Cosmological Perturbations at z∼0.1 from a New Observational Test

    NASA Astrophysics Data System (ADS)

    Feix, Martin; Nusser, Adi; Branchini, Enzo

    2015-07-01

    Spatial variations in the distribution of galaxy luminosities, estimated from redshifts as distance proxies, are correlated with the peculiar velocity field. Comparing these variations with the peculiar velocities inferred from galaxy redshift surveys is a powerful test of gravity and dark-energy theories on cosmological scales. Using ∼2 ×105 galaxies from the SDSS Data Release 7, we perform this test in the framework of gravitational instability to estimate the normalized growth rate of density perturbations f σ8=0.37 ±0.13 at z ∼0.1 , which is in agreement with the cold dark matter model with a cosmological constant. This unique measurement is complementary to those obtained with more traditional methods, including clustering analysis. The estimated accuracy at z ∼0.1 is competitive with other methods when applied to similar data sets.

  10. Comparative effects of plant growth regulators on leaf and stem explants of Labisia pumila var. alata

    PubMed Central

    Ling, Anna Pick Kiong; Tan, Kinn Poay; Hussein, Sobri

    2013-01-01

    Objective: Labisia pumila var. alata, commonly known as ‘Kacip Fatimah’ or ‘Selusuh Fatimah’ in Southeast Asia, is traditionally used by members of the Malay community because of its post-partum medicinal properties. Its various pharmaceutical applications cause an excessive harvesting and lead to serious shortage in natural habitat. Thus, this in vitro propagation study investigated the effects of different plant growth regulators (PGRs) on in vitro leaf and stem explants of L. pumila. Methods: The capabilities of callus, shoot, and root formation were evaluated by culturing both explants on Murashige and Skoog (MS) medium supplemented with various PGRs at the concentrations of 0, 1, 3, 5, and 7 mg/L. Results: Medium supplemented with 3 mg/L indole-3-butyric acid (IBA) showed the optimal callogenesis from both leaf and stem explants with (72.34±19.55)% and (70.40±14.14)% efficacy, respectively. IBA was also found to be the most efficient PGR for root induction. A total of (50.00±7.07)% and (77.78±16.47)% of root formation were obtained from the in vitro stem and leaf explants after being cultured for (26.5±5.0) and (30.0±8.5) d in the medium supplemented with 1 and 3 mg/L of IBA, respectively. Shoot formation was only observed in stem explant, with the maximum percentage of formation ((100.00±0.00)%) that was obtained in 1 mg/L zeatin after (11.0±2.8) d of culture. Conclusions: Callus, roots, and shoots can be induced from in vitro leaf and stem explants of L. pumila through the manipulation of types and concentrations of PGRs. PMID:23825148

  11. Growth of a young pingo in the Canadian Arctic observed by RADARSAT-2 interferometric satellite radar

    NASA Astrophysics Data System (ADS)

    Samsonov, S. V.; Lantz, T. C.; Kokelj, S. V.; Zhang, Y.

    2015-11-01

    Advancements in radar technology are increasing our ability to detect earth surface deformation in permafrost environments. In this paper we use satellite Differential Interferometric Synthetic Aperture Radar (DInSAR) to describe the growth of a previously unreported pingo in the Tuktoyaktuk Coastlands. High-resolution RADARSAT-2 imagery (2011-2014) analyzed with the Multidimensional Small Baseline Subset (MSBAS) DInSAR revealed a maximum 2.7 cm yr-1 of domed uplift located in a drained lake basin. Observed changes in elevation were modeled as a 348 m × 290 m uniformly loaded elliptical plate with clamped edge. Model results suggest that this feature is one of the largest diameter pingos in the region that is presently growing. Analysis of historical aerial photographs showed that ground uplift at this location initiated sometime between 1935 and 1951 following lake drainage. Uplift is largely due to the growth of intrusive ice, because the 9 % expansion of pore water associated with permafrost aggradation into saturated sands is not sufficient to explain the observed short- and long-term deformation rates. The modeled thickness of permafrost using the Northern Ecosystem Soil Temperature (NEST) was consistent with the maximum height of this feature and the 1972-2014 elevation changes estimated from aerial photographs, suggesting that permafrost aggradation is resulting in the freezing a sub-pingo water lens. Seasonal variation in the uplift rate seen in the DInSAR data also matches the modeled seasonal pattern in the deepening rate of freezing front. This study demonstrates that interferometric satellite radar can successfully contribute to understanding the dynamics of terrain uplift in response to permafrost aggradation and ground ice development in remote polar environments, and highlights possible application of detecting deformation of Martian landscapes. However, our DInSAR data did not show clear growth at other smaller pingos in contrast with field studies

  12. Three-dimensional simulations of gravitationally confined detonations compared to observations of SN 1991T

    NASA Astrophysics Data System (ADS)

    Seitenzahl, Ivo R.; Kromer, Markus; Ohlmann, Sebastian T.; Ciaraldi-Schoolmann, Franco; Marquardt, Kai; Fink, Michael; Hillebrandt, Wolfgang; Pakmor, Rüdiger; Röpke, Friedrich K.; Ruiter, Ashley J.; Sim, Stuart A.; Taubenberger, Stefan

    2016-07-01

    The gravitationally confined detonation (GCD) model has been proposed as a possible explosion mechanism for Type Ia supernovae in the single-degenerate evolution channel. It starts with ignition of a deflagration in a single off-centre bubble in a near-Chandrasekhar-mass white dwarf. Driven by buoyancy, the deflagration flame rises in a narrow cone towards the surface. For the most part, the main component of the flow of the expanding ashes remains radial, but upon reaching the outer, low-pressure layers of the white dwarf, an additional lateral component develops. This causes the deflagration ashes to converge again at the opposite side, where the compression heats fuel and a detonation may be launched. We first performed five three-dimensional hydrodynamic simulations of the deflagration phase in 1.4 M⊙ carbon/oxygen white dwarfs at intermediate-resolution (2563 computational zones). We confirm that the closer the initial deflagration is ignited to the centre, the slower the buoyant rise and the longer the deflagration ashes takes to break out and close in on the opposite pole to collide. To test the GCD explosion model, we then performed a high-resolution (5123 computational zones) simulation for a model with an ignition spot offset near the upper limit of what is still justifiable, 200 km. This high-resolution simulation met our deliberately optimistic detonation criteria, and we initiated a detonation. The detonation burned through the white dwarf and led to its complete disruption. For this model, we determined detailed nucleosynthetic yields by post-processing 106 tracer particles with a 384 nuclide reaction network, and we present multi-band light curves and time-dependent optical spectra. We find that our synthetic observables show a prominent viewing-angle sensitivity in ultraviolet and blue wavelength bands, which contradicts observed SNe Ia. The strong dependence on the viewing angle is caused by the asymmetric distribution of the deflagration ashes

  13. In-situ observation of electric-field-induced acceleration in crystal growth of tetrathiafulvalene-tetracyanoquinodimethane

    NASA Astrophysics Data System (ADS)

    Sakai, Masatoshi; Kuniyoshi, Shigekazu; Yamauchi, Hiroshi; Iizuka, Masaaki; Nakamura, Masakazu; Kudo, Kazuhiro

    2013-04-01

    In-situ observations of vapor-phase growth of tetrathiafulvalene (TTF)-tetracyanoquinodimethane (TCNQ) crystals under an electric field were conducted without influencing the actual crystal growth process. The shortest incubation time of TTF-TCNQ nuclei and the highest initial growth rate of the crystals are obtained on the anode side and in high electric field regions. It is demonstrated that the distribution of molecules thermally diffusing on the substrate surface is controlled by an external electric field. These results indicate the potential for selective growth of highly conductive organic wires for micro- and nanoscale wiring in organic nanodevices.

  14. Comparing digital software to human observation for estimating weed cover in nursery containers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Researchers who study weed management in nursery crops often rely on visual ratings to assess weed growth in response to some treatment effect. Visual weed ratings are easy to perform, non-destructive, and do not require any special equipment. However, visual ratings are prone to bias and skewed j...

  15. Formation and growth rates of atmospheric nanoparticles: four years of observations at two West Siberian stations

    NASA Astrophysics Data System (ADS)

    Arshinov, Mikhail Yu.; Belan, Boris D.; Davydov, Denis K.; Kozlov, Artem V.; Arshinova, Victoria

    2015-04-01

    In spite of fact that the first report on the new particle formation (NPF) itself was done by John Aitken more than one century ago (Aitken, 1898), a phenomenon of NPF bursts taken place in the atmosphere was discovered not very long ago. Nevertheless, to date it is known that they may occur quite often in a variety of environments (Kulmala et al., 2004; Hirsikko et al., 2011). Siberia occupies a vast area covered by forests, but the comprehensive data on burst frequency, as well as on formation and growth rates of freshly nucleated particles in this key region are still lacking. Continuous measurements of aerosol size distribution carried out in recent years at two West Siberian stations (TOR-station - 56o28'41"N, 85o03'15"E; Fonovaya Observatory - 56o25'07"N, 84o04'27"E) allowed this gap in data to be filled up. Analysis of the size spectra classified in accordance with criteria proposed by Dal Maso et al. (2005) and Hammed et al. (2007) enabled a conclusion to be drawn that NPF events in Wets Siberia are more often observed during spring (from March to May) and early autumn (secondary frequency peak in September). On average, particle formation bursts took place on 23-28 % of all days. Such a seasonal pattern of the NPF occurrence is very similar to one observed at SMEAR II Station (Hyytiälä, Finland; Dal Maso et al. 2005, 2007). Formation rates (FR) of particles with diameters below 25 nm varied in a wide range from 0.1 to 10 cm-3 s-1. Mean values of FR for the entire period of observations were 1.7 cm-3s-1 (median = 1.13 cm-3 s-1) at TOR-station and 0.88 cm-3 s-1 (median = 0.69 cm-3 s-1) at Fonovaya Observatory. Enhanced values of FR are usually observed from spring to autumn. Mean growth rates of observed at TOR-station and Fonovaya Observatory were 6.5 nm h-1 (median = 5.0 nm h-1) and 8.3 nm h-1 (median = 6.4 nm h-1), respectively. This work was supported by the Branch of Geology, Geophysics and Mining Sciences of RAS (Program No. 5); State contracts of

  16. Russian geomagnetic recordings in 1850-1862 compared to modern observations

    NASA Astrophysics Data System (ADS)

    Viljanen, Ari; Myllys, Minna; Nevanlinna, Heikki

    2014-04-01

    We analyse geomagnetic recordings at four subauroral and midlatitude Russian observatories in 1850-1862. The data consist of spot readings made once in hour of the north and east components of the magnetic field. We use the hourly change of the horizontal field vector as the measure of activity. We compare these values to data from modern observatories at corresponding magnetic latitudes (Nurmijärvi, Finland, magnetic latitude ~57 N; Tartu, Estonia, ~54.5 N; Dourbes, Belgium, ~46 N) by reducing their data to the 1-h format. The largest variations at the Russian observatories occurred during the Carrington storm in September 1859 and they reached about 1000 nT/h, which was the instrumental off-scale limit. When the time stamp for the spot readings happens to be optimal, the top variation in the Nurmijärvi data is about 3700 nT/h (July 1982), and at Tartu the maximum is about 1600 nT/h (November 2004). At a midlatitude site Nertchinsk in Russia (magnetic latitude ~45 N), the variation during the Carrington storm was at the off-scale limit, and exceeded the value observed at Dourbes during the Halloween storm in October 2003. At Nertchinsk, the Carrington event was at least four times larger than any other storm in 1850-1862. Despite the limitations of the old recordings and in using only hourly spot readings, the Carrington storm was definitely a very large event at midlatitudes. At higher latitudes, it remains somewhat unclear whether it exceeds the largest modern storms, especially the one in July 1982.

  17. CFD Simulations of Supersonic Highly Swirling Flow Exiting a Turbine Vane Row Compared with Experimental Observations

    NASA Technical Reports Server (NTRS)

    West, Jeff S.; Richardson, Brian R.; Schmauch, Preston; Kenny, Robert J.

    2011-01-01

    Marshall Space Flight Center (MSFC) has been heavily involved in developing the J2-X engine. The Center has been testing a Work Horse Gas Generator (WHGG) to supply gas products to J2-X turbine components at realistic flight-like operating conditions. Three-dimensional time accurate CFD simulations and analytical fluid analysis have been performed to support WHGG tests at MSFC. The general purpose CFD program LOCI/Chem was utilized to simulate flow of products from the WHGG through a turbine manifold, a stationary row of turbine vanes, into a Can and orifice assembly used to control the back pressure at the turbine vane row and finally through an aspirator plate and flame bucket. Simulations showed that supersonic swirling flow downstream of the turbine imparted a much higher pressure on the Can wall than expected for a non-swirling flow. This result was verified by developing an analytical model that predicts wall pressure due to swirling flow. The CFD simulations predicted that the higher downstream pressure would cause the pressure drop across the nozzle row to be approximately half the value of the test objective. With CFD support, a redesign of the Can orifice and aspirator plate was performed. WHGG experimental results and observations compared well with pre-test and post-test CFD simulations. CFD simulations for both quasi-static and transient test conditions correctly predicted the pressure environment downstream of the turbine row and the behavior of the gas generator product plume as it exited the WHGG test article, impacted the flame bucket and interacted with the external environment.

  18. Detection of pulmonary nodule growth with dose reduced chest tomosynthesis: a human observer study using simulated nodules

    NASA Astrophysics Data System (ADS)

    Söderman, Christina; Johnsson, Ã. se; Vikgren, Jenny; Rossi Norrlund, Rauni; Molnar, David; Mirzai, Maral; Svalkvist, Angelica; Mânsson, Lars Gunnar; Bâth, Magnus

    2016-03-01

    Chest tomosynthesis may be a suitable alternative to computed tomography for the clinical task of follow up of pulmonary nodules. The aim of the present study was to investigate the detection of pulmonary nodule growth suggestive of malignancy using chest tomosynthesis. Previous studies have indicated remained levels of detection of pulmonary nodules at dose levels corresponding to that of a conventional lateral radiograph, approximately 0.04 mSv, which motivated to perform the present study this dose level. Pairs of chest tomosynthesis image sets, where the image sets in each pair were acquired of the same patient at two separate occasions, were included in the study. Simulated nodules with original diameters of approximately 8 mm were inserted in the pairs of image sets, simulating situations where the nodule had remained stable in size or increased isotropically in size between the two different imaging occasions. Four different categories of nodule growth were included, corresponding to a volume increase of approximately 21 %, 68 %, 108 % and 250 %. All nodules were centered in the depth direction in the tomosynthesis images. All images were subjected to a simulated dose reduction, resulting in images corresponding to an effective dose of 0.04 mSv. Four observers were given the task of rating their confidence that the nodule was stable in size or not on a five-level rating scale. This was done both before any size measurements were made of the nodule as well as after measurements were performed. Using Receiver operating characteristic analysis, the rating data for the nodules that were stable in size was compared to the rating data for the nodules simulated to have increased in size. Statistically significant differences between the rating distributions for the stable nodules and all of the four nodule growth categories were found. For the three largest nodule growths, nearly perfect detection of nodule growth was seen. In conclusion, the present study

  19. Comparative Effect of ACTH and Related Peptides on Proliferation and Growth of Rat Adrenal Gland

    PubMed Central

    Lotfi, Claudimara Ferini Pacicco; de Mendonca, Pedro O. R.

    2016-01-01

    Pro-opiomelanocortin (POMC) is a polypeptide precursor known to yield biologically active peptides related to a range of functions. These active peptides include the adrenocorticotropic hormone (ACTH), which is essential for maintenance of adrenal growth and steroidogenesis, and the alpha-melanocyte stimulation hormone, which plays a key role in energy homeostasis. However, the role of the highly conserved N-terminal region of POMC peptide fragments has begun to be unraveled only recently. Here, we review the cascade of events involved in regulation of proliferation and growth of murine adrenal cortex triggered by ACTH and other POMC-derived peptides. Key findings regarding signaling pathways and modulation of genes and proteins required for the regulation of adrenal growth are summarized. We have outlined the known mechanisms as well as future challenges for research on the regulation of adrenal proliferation and growth triggered by these peptides. PMID:27242663

  20. A comparative field study of growth and survival of Sierran conifer seedlings

    SciTech Connect

    Kern, R.A.

    1996-12-31

    This study is a comparison of seedling growth and survival of seven species of conifers that make up the mid-elevation Sierra Nevada mixed conifer forest--Abies concolor, Abies magnifica, Calocedrus decurrens, Pinus jeffreyi, Pinus lambertiana, Pinus ponderosa, and Sequoiadendron giganteum. The field experiment was designed to test the hypothesis that seedling demography is affected by the study species` relatively shade and drought tolerances. Six discrete treatments were created in the first experiment by using three elevations (1,600 m, 1,900, m, and 2,200 m) and two natural light levels (closed canopy shade and open gap sun) at each elevation. One or two-year old seedlings were planted in the ground in replicate plots in each treatment and followed for two growing seasons. Four responses were analyzed--survival, height growth, diameter growth, and mass growth (total mass as well as root mass and shoot mass separately).

  1. Diversity in human hair growth, diameter, colour and shape. An in vivo study on young adults from 24 different ethnic groups observed in the five continents.

    PubMed

    Loussouarn, Geneviève; Lozano, Isabelle; Panhard, Ségolène; Collaudin, Catherine; El Rawadi, Charles; Genain, Gilles

    2016-04-01

    Based on previous findings, from a worldwide study, classified the shapes of human hair into 8 major types, from straight to highly curly. This clearly extended the usual classification of hair into African, Asian or Caucasian types. However, determinations of hair growth parameters and hair density were excluded from such studies. To measure and compare the hair growth profiles of young adults without alopecia living in the five continents. 2249 young adults (18-35 years, females and males) without alopecia, originating from 24 various human ethnic groups were included in the study. Total hair density, telogen percentage and growth rate on three different scalp areas were measured, using non-invasive validated techniques. Natural hair colour level, curliness and hair diameter were additionally recorded, when practically possible. Diversity in hair growth parameters among the entire cohort was a key finding, with differences linked to scalp area, gender and geographic origin. Statistical approaches depicted African hair as having lower density and a slower growth rate. Asian hair showed a thicker diameter, with faster growth. Caucasian hair showed a high total hair density. On the one hand, this inter-continental study of hair growth parameters provides initial valuable base-line data on hair in young adults without alopecia, and on the other hand, further extends our knowledge of this unique human appendage, with some mosaic features, observed worldwide. PMID:27019510

  2. Development of density plumes of dissolved CO2: Comparing experimental observations with numerical simulations

    NASA Astrophysics Data System (ADS)

    Kirk, Karen; Vosper, Hayley; Rochelle, Chris; Noy, Dave; Chadwick, Andy

    2014-05-01

    The long-term trapping of CO2 within deep geological storage reservoirs will be dependent upon CO2-water-rock geochemical reactions. The first, and most important, steps in this process will be dissolution of CO2 into the reservoir porewater and the transport of this dissolved CO2 through the reservoir. As part of the CO2CARE project we have investigated these via laboratory tests using a water-filled porous medium. Key experimental parameters were measured to determine system permeability, so that a high-resolution numerical model could be built in an attempt to reproduce the observed system behaviour. The Hele-Shaw cell comprised two glass sheets 65 cm wide and 36 cm high, separated by a spacing of 1.1 mm, and filled with closely-packed glass beads 0.4-0.6 mm in diameter. The surface of the glass was treated to prevent the formation of a higher permeability zone along this interface. A pH-sensitive dye was added to the pore-filling water to show where it had been acidified due to the presence of CO2. CO2 gas was introduced to a space at the top of the cell, which created a thin, diffusion-controlled boundary layer of CO2-rich water below the CO2-water interface. CO2 dissolution increased water density, resulting in gravitational instabilities and the formation of many small, downward-migrating plumes. Time-lapse photography was used to track the formation and progress of these plumes. As the plumes grew they increased in length relative to their width, and decreased in number over time. They also became more complex with time, splitting and forming several lobes, whose outer edges became more diffuse as they mixed with the CO2-poor water. The onset time of plume development and the horizontal wavelength (spacing) of the descending plumes are diagnostic measures of the system properties, notably permeability. They were analysed from the time-lapse images and expressed as probability density functions based on histograms of the observations. The derived

  3. Comparing offshore wind farm wake observed from satellite SAR and wake model results

    NASA Astrophysics Data System (ADS)

    Bay Hasager, Charlotte

    2014-05-01

    Offshore winds can be observed from satellite synthetic aperture radar (SAR). In the FP7 EERA DTOC project, the European Energy Research Alliance project on Design Tools for Offshore Wind Farm Clusters, there is focus on mid- to far-field wind farm wakes. The more wind farms are constructed nearby other wind farms, the more is the potential loss in annual energy production in all neighboring wind farms due to wind farm cluster effects. It is of course dependent upon the prevailing wind directions and wind speed levels, the distance between the wind farms, the wind turbine sizes and spacing. Some knowledge is available within wind farm arrays and in the near-field from various investigations. There are 58 offshore wind farms in the Northern European seas grid connected and in operation. Several of those are spaced near each other. There are several twin wind farms in operation including Nysted-1 and Rødsand-2 in the Baltic Sea, and Horns Rev 1 and Horns Rev 2, Egmond aan Zee and Prinses Amalia, and Thompton 1 and Thompton 2 all in the North Sea. There are ambitious plans of constructing numerous wind farms - great clusters of offshore wind farms. Current investigation of offshore wind farms includes mapping from high-resolution satellite SAR of several of the offshore wind farms in operation in the North Sea. Around 20 images with wind farm wake cases have been retrieved and processed. The data are from the Canadian RADARSAT-1/-2 satellites. These observe in microwave C-band and have been used for ocean surface wind retrieval during several years. The satellite wind maps are valid at 10 m above sea level. The wakes are identified in the raw images as darker areas downwind of the wind farms. In the SAR-based wind maps the wake deficit is found as areas of lower winds downwind of the wind farms compared to parallel undisturbed flow in the flow direction. The wind direction is clearly visible from lee effects and wind streaks in the images. The wind farm wake cases

  4. Comparative secretome analysis of Streptomyces scabiei during growth in the presence or absence of potato suberin

    PubMed Central

    2014-01-01

    Background Suberin is a recalcitrant plant biopolymer composed of a polyphenolic and a polyaliphatic domain. Although suberin contributes to a significant portion of soil organic matter, the biological process of suberin degradation is poorly characterized. It has been suggested that Streptomyces scabiei, a plant pathogenic bacterium, can produce suberin-degrading enzymes. In this study, a comparative analysis of the S. scabiei secretome from culture media supplemented or not with potato suberin was carried out to identify enzymes that could be involved in suberin degradation. Methods S. scabiei was grown in the presence of casein only or in the presence of both casein and suberin. Extracellular proteins from 1-, 3- and 5-day-old supernatants were analyzed by LC-MS/MS to determine their putative functions. Real-time RT-PCR was performed to monitor the expression level of genes encoding several proteins potentially involved in suberin degradation. Results The effect of suberin on the extracellular protein profile of S. scabiei strain has been analyzed. A total of 246 proteins were found to be common in the data sets from both casein medium (CM) and casein-suberin medium (CSM), whereas 124 and 139 proteins were detected only in CM or CSM, respectively. The identified proteins could be divided into 19 functional groups. Two functional groups of proteins (degradation of aromatic compounds and secondary metabolism) were only associated with the CSM. A high proportion of the proteins found to be either exclusively produced, or overproduced, in presence of suberin were involved in carbohydrate metabolism. Most of the proteins included in the lipid metabolism class have been detected in CSM. Apart from lipid metabolism proteins, other identified proteins, particularly two feruloyl esterases, may also actively participate in the breakdown of suberin architecture. Both feruloyl esterase genes were overexpressed between 30 to 340 times in the presence of suberin. Conclusion

  5. Variation of Jupiter's aurora observed by Hisaki/EXCEED: 1. Observed characteristics of the auroral electron energies compared with observations performed using HST/STIS

    NASA Astrophysics Data System (ADS)

    Tao, Chihiro; Kimura, Tomoki; Badman, Sarah V.; Murakami, Go; Yoshioka, Kazuo; Tsuchiya, Fuminori; André, Nicolas; Yoshikawa, Ichiro; Yamazaki, Atsushi; Shiota, Daikou; Tadokoro, Hiroyasu; Fujimoto, Masaki

    2016-05-01

    Temporal variation of Jupiter's northern aurora is detected using the Extreme Ultraviolet Spectroscope for Exospheric Dynamics (EXCEED) on board JAXA's Earth-orbiting planetary space telescope Hisaki. The wavelength coverage of EXCEED includes the H2 Lyman and Werner bands at 80-148 nm from the entire northern polar region. The prominent periodic modulation of the observed emission corresponds to the rotation of Jupiter's main auroral oval through the aperture, with additional superposed -50%-100% temporal variations. The hydrocarbon color ratio (CR) adopted for the wavelength range of EXCEED is defined as the ratio of the emission intensity in the long wavelength range of 138.5-144.8 nm to that in the short wavelength range of 126.3-130 nm. This CR varies with the planetary rotation phase. Short- (within one planetary rotation) and long-term (> one planetary rotation) enhancements of the auroral power are observed in both wavelength ranges and result in a small CR variation. The occurrence timing of the auroral power enhancement does not clearly depend on the central meridian longitude. Despite the limitations of the wavelength coverage and the large field of view of the observation, the auroral spectra and CR-brightness distribution measured using EXCEED are consistent with other observations.

  6. Whole season compared to growth-stage resolved temperature trends: implications for US maize yield

    NASA Astrophysics Data System (ADS)

    Butler, E. E.; Mueller, N. D.; Huybers, P. J.

    2014-12-01

    The effect of temperature on maize yield has generally been considered using a single value for the entire growing season. We compare the effect of temperature trends on yield between two distinct models: a single temperature sensitivity for the whole season and a variable sensitivity across four distinct agronomic development stages. The more resolved variable-sensitivity model indicates roughly a factor of two greater influence of temperature on yield than that implied by the single-sensitivity model. The largest discrepancies occur in silking, which is demonstrated to be the most sensitive stage in the variable-sensitivity model. For instance, whereas median yields are observed to be only 53% of typical values during the hottest 1% of silking-stage temperatures, the single-sensitivity model over predicts median yields of 68% whereas the variable-sensitivity model more correctly predicts median yields of 61%. That the variable sensitivity model is also not capable of capturing the full extent of yield losses suggests that further refinement to represent the non-linear response would be useful. Results from the variable sensitivity model also indicate that management decisions regarding planting times, which have generally shifted toward earlier dates, have led to greater yield benefit than that implied by the single-sensitivity model. Together, the variation of both temperature trends and yield variability within growing stages calls for closer attention to how changes in management interact with changes in climate to ultimately affect yields.

  7. In-situ observation of HB GaAs crystal growth

    NASA Astrophysics Data System (ADS)

    Kuo, J. Y.; Guo, Y. D.; Hsu, Juei-Tsang

    1992-10-01

    In-situ monitoring of horizontal Bridgman (HB) growth of GaAs crystals through the furnace window can reveal whether the growth condition is good or not. Good growth conditions are characterized by straight melt/crystal interface and (111) facet growth striations on the grown crystal surface. Abnormal growth conditions including twinning, lineaging and polycrystallizing in the growing crystals usually show curved or irregular-shaped melt/crystal interface and various slanted lines distributed over the crystal surfaces. The monitoring process can spot these defective conditions in the early stage of their formations, and growth parameters thus can be adjusted in real time for correction. It provides a convenient way to help understand the relations between growth parameters and defects formation. The yield and quality of the M2T-HB grown crystals are both increased by this method.

  8. Comparative growth and yield of channel catfish and channel x blue hybrid catfish fed a full or restricted ration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Growth and yield (kg ha-1) of the channel catfish (Ictalurus punctatus, Rafinesque, 1818) and the channel x blue hybrid catfish (I. punctatus female x I. furcatus [Lesueur, 1840] male), which shared the Jubilee strain of channel catfish as the maternal parent, were compared in 16 0.1-ha earthen pond...

  9. Comparative Study of Population Growth and Agricultural Change: C - Case Study of India. Asian Population Studies Series No. 23.

    ERIC Educational Resources Information Center

    United Nations Economic and Social Commission for Asia and the Pacific, Bangkok (Thailand).

    This report, the third in a series of five reports of the Comparative Study of Population Growth and Agricultural Change, describes a study of the two states of India (Punjaband and Orissa) which attempted to clarify the relationship between population pressure and agricultural change through a time series analysis. This study: (1) outlines trends…

  10. A new method to compare statistical tree growth curves: the PL-GMANOVA model and its application with dendrochronological data.

    PubMed

    Ricker, Martin; Peña Ramírez, Víctor M; von Rosen, Dietrich

    2014-01-01

    Growth curves are monotonically increasing functions that measure repeatedly the same subjects over time. The classical growth curve model in the statistical literature is the Generalized Multivariate Analysis of Variance (GMANOVA) model. In order to model the tree trunk radius (r) over time (t) of trees on different sites, GMANOVA is combined here with the adapted PL regression model Q = A · T+E, where for b ≠ 0 : Q = Ei[-b · r]-Ei[-b · r1] and for b = 0 : Q  = Ln[r/r1], A =  initial relative growth to be estimated, T = t-t1, and E is an error term for each tree and time point. Furthermore, Ei[-b · r]  = ∫(Exp[-b · r]/r)dr, b = -1/TPR, with TPR being the turning point radius in a sigmoid curve, and r1 at t1 is an estimated calibrating time-radius point. Advantages of the approach are that growth rates can be compared among growth curves with different turning point radiuses and different starting points, hidden outliers are easily detectable, the method is statistically robust, and heteroscedasticity of the residuals among time points is allowed. The model was implemented with dendrochronological data of 235 Pinus montezumae trees on ten Mexican volcano sites to calculate comparison intervals for the estimated initial relative growth A. One site (at the Popocatépetl volcano) stood out, with A being 3.9 times the value of the site with the slowest-growing trees. Calculating variance components for the initial relative growth, 34% of the growth variation was found among sites, 31% among trees, and 35% over time. Without the Popocatépetl site, the numbers changed to 7%, 42%, and 51%. Further explanation of differences in growth would need to focus on factors that vary within sites and over time. PMID:25402427

  11. A New Method to Compare Statistical Tree Growth Curves: The PL-GMANOVA Model and Its Application with Dendrochronological Data

    PubMed Central

    Ricker, Martin; Peña Ramírez, Víctor M.; von Rosen, Dietrich

    2014-01-01

    Growth curves are monotonically increasing functions that measure repeatedly the same subjects over time. The classical growth curve model in the statistical literature is the Generalized Multivariate Analysis of Variance (GMANOVA) model. In order to model the tree trunk radius (r) over time (t) of trees on different sites, GMANOVA is combined here with the adapted PL regression model Q = A·T+E, where for and for , A =  initial relative growth to be estimated, , and E is an error term for each tree and time point. Furthermore, Ei[–b·r]  = , , with TPR being the turning point radius in a sigmoid curve, and at is an estimated calibrating time-radius point. Advantages of the approach are that growth rates can be compared among growth curves with different turning point radiuses and different starting points, hidden outliers are easily detectable, the method is statistically robust, and heteroscedasticity of the residuals among time points is allowed. The model was implemented with dendrochronological data of 235 Pinus montezumae trees on ten Mexican volcano sites to calculate comparison intervals for the estimated initial relative growth . One site (at the Popocatépetl volcano) stood out, with being 3.9 times the value of the site with the slowest-growing trees. Calculating variance components for the initial relative growth, 34% of the growth variation was found among sites, 31% among trees, and 35% over time. Without the Popocatépetl site, the numbers changed to 7%, 42%, and 51%. Further explanation of differences in growth would need to focus on factors that vary within sites and over time. PMID:25402427

  12. Growth

    NASA Astrophysics Data System (ADS)

    Waag, Andreas

    This chapter is devoted to the growth of ZnO. It starts with various techniques to grow bulk samples and presents in some detail the growth of epitaxial layers by metal organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), and pulsed laser deposition (PLD). The last section is devoted to the growth of nanorods. Some properties of the resulting samples are also presented. If a comparison between GaN and ZnO is made, very often the huge variety of different growth techniques available to fabricate ZnO is said to be an advantage of this material system. Indeed, growth techniques range from low cost wet chemical growth at almost room temperature to high quality MOCVD growth at temperatures above 1, 000∘C. In most cases, there is a very strong tendency of c-axis oriented growth, with a much higher growth rate in c-direction as compared to other crystal directions. This often leads to columnar structures, even at relatively low temperatures. However, it is, in general, not straight forward to fabricate smooth ZnO thin films with flat surfaces. Another advantage of a potential ZnO technology is said to be the possibility to grow thin films homoepitaxially on ZnO substrates. ZnO substrates are mostly fabricated by vapor phase transport (VPT) or hydrothermal growth. These techniques are enabling high volume manufacturing at reasonable cost, at least in principle. The availability of homoepitaxial substrates should be beneficial to the development of ZnO technology and devices and is in contrast to the situation of GaN. However, even though a number of companies are developing ZnO substrates, only recently good quality substrates have been demonstrated. However, these substrates are not yet widely available. Still, the situation concerning ZnO substrates seems to be far from low-cost, high-volume production. The fabrication of dense, single crystal thin films is, in general, surprisingly difficult, even when ZnO is grown on a ZnO substrate. However

  13. Some 2015 Measurements of Wide and Faint Double Stars Compared with Visual Observations

    NASA Astrophysics Data System (ADS)

    Knapp, Wilfried

    2016-07-01

    A backlog of astrometry and photometry measurements made in 2015 for comparison with visual observations is reported here with the intention of providing recent precise measurements for the given objects.

  14. Global numerical simulation of the growth phase and the expansion onset for a substorm observed by Viking

    SciTech Connect

    Fedder, J.A.; Slinker, S.P.; Lyon, J.G.

    1995-10-01

    The authors report the first global magnetohydrodynamic (MHD) simulation of an actual magnetospheric substorm, which was recorded by the Viking spacecraft on October 19, 1986. The simulation is driven by IMP 8 solar wind parameters measured upstream of the Earth`s bow shock. The substorm, which had expansion onset at 1132 UT, was caused by a brief period of southward interplanetary magnetic field (IMF) and two weak solar wind shocks. The simulation model includes a self-consistent auroral ionospheric conductance depending directly on the MHD magnetospheric plasma parameters and magnetic field. Synthetic auroral emissions, derived from simulation results, are compared to the Viking images, which show considerable dayside activity preceding the substorm. The authors also compare model-derived synthetic AU and AL indices to geomagnetic measurements. The simulation results are seen to be in reasonable agreement with the observations throughout the growth phase and expansion onset. Moreover, the results allow the authors to form conclusions concerning which essential processes were responsible for the substorm occurrence. These results are a highly encouraging first step leading toward development of a space weather forecasting methodology based on the directly measured solar input. 19 refs., 5 figs.

  15. Bias in Observational Studies of Prevalent Users: Lessons for Comparative Effectiveness Research From a Meta-Analysis of Statins

    PubMed Central

    Danaei, Goodarz; Tavakkoli, Mohammad; Hernán, Miguel A.

    2012-01-01

    Randomized clinical trials (RCTs) are usually the preferred strategy with which to generate evidence of comparative effectiveness, but conducting an RCT is not always feasible. Though observational studies and RCTs often provide comparable estimates, the questioning of observational analyses has recently intensified because of randomized-observational discrepancies regarding the effect of postmenopausal hormone replacement therapy on coronary heart disease. Reanalyses of observational data that excluded prevalent users of hormone replacement therapy led to attenuated discrepancies, which begs the question of whether exclusion of prevalent users should be generally recommended. In the current study, the authors evaluated the effect of excluding prevalent users of statins in a meta-analysis of observational studies of persons with cardiovascular disease. The pooled, multivariate-adjusted mortality hazard ratio for statin use was 0.77 (95% confidence interval (CI): 0.65, 0.91) in 4 studies that compared incident users with nonusers, 0.70 (95% CI: 0.64, 0.78) in 13 studies that compared a combination of prevalent and incident users with nonusers, and 0.54 (95% CI: 0.45, 0.66) in 13 studies that compared prevalent users with nonusers. The corresponding hazard ratio from 18 RCTs was 0.84 (95% CI: 0.77, 0.91). It appears that the greater the proportion of prevalent statin users in observational studies, the larger the discrepancy between observational and randomized estimates. PMID:22223710

  16. A new design strategy for observing lithium oxide growth-evolution interactions using geometric catalyst positioning

    DOE PAGESBeta

    Ryu, Won -Hee; Gittleson, Forrest S.; Li, Jinyang; Tong, Xiao; Taylor, Andre D.

    2016-06-21

    Understanding the catalyzed formation and evolution of lithium-oxide products in Li-O2 batteries is central to the development of next-generation energy storage technology. Catalytic sites, while effective in lowering reaction barriers, often become deactivated when placed on the surface of an oxygen electrode due to passivation by solid products. Here we investigate a mechanism for alleviating catalyst deactivation by dispersing Pd catalytic sites away from the oxygen electrode surface in a well-structured anodic aluminum oxide (AAO) porous membrane interlayer. We observe the cross-sectional product growth and evolution in Li-O2 cells by characterizing products that grow from the electrode surface. Morphological andmore » structural details of the products in both catalyzed and uncatalyzed cells are investigated independently from the influence of the oxygen electrode. We find that the geometric decoration of catalysts far from the conductive electrode surface significantly improves the reaction reversibility by chemically facilitating the oxidation reaction through local coordination with PdO surfaces. Lastly, the influence of the catalyst position on product composition is further verified by ex situ Xray photoelectron spectroscopy and Raman spectroscopy in addition to morphological studies.« less

  17. Sonographic Growth Charts for Kidney Length in Normal Korean Children: a Prospective Observational Study.

    PubMed

    Oh, Min-Su; Hwang, Geol; Han, Sanghoon; Kang, Hyun Sik; Kim, Seung Hyo; Kim, Young Don; Kang, Ki-Soo; Shin, Kyung-Sue; Lee, Mu Sook; Choi, Guk Myung; Han, Kyoung Hee

    2016-07-01

    Kidney length is the most useful parameter for clinical measurement of kidney size, and is useful to distinguish acute kidney injury from chronic kidney disease. In this prospective observational study of 437 normal children aged between 0 and < 13 years, kidney length was measured using sonography. There were good correlations between kidney length and somatic values, including age, weight, height, and body surface area. The rapid growth of height during the first 2 years of life was intimately associated with a similar increase in kidney length, suggesting that height should be considered an important factor correlating with kidney length. Based on our findings, the following regression equation for the reference values of bilateral kidney length for Korean children was obtained: kidney length of the right kidney (cm) = 0.051 × height (cm) + 2.102; kidney length of the left kidney (cm) = 0.051 × height (cm) + 2.280. This equation may aid in the diagnosis of various kidney disorders. PMID:27366007

  18. In situ observation of containerless protein crystallization by magnetically levitating crystal growth

    NASA Astrophysics Data System (ADS)

    Maki, Syou; Tanimoto, Yoshifumi; Udagawa, Chikako; Morimoto, Shotaro; Hagiwara, Masayuki

    2016-03-01

    We report on the results of the crystal growth of hen-egg lysozyme by magnetically levitating crystals in a small amount of buffer solution. The concentrations of lysozyme and the precipitating agent (gadolinium chloride) were 6.53 wt % and 0.362 mol/kg, respectively. Gadolinium chloride, which induces the magneto-Archimedes effect, was utilized to levitate the crystals with Bz · (dBz/dz) = 22.46 T2/m, where Bz is the vertical (z) component of the magnetic flux density vector. Although the collected crystals were small, we succeeded in maintaining the levitation of the crystals into a specific place in the liquid phase from the beginning of nucleation. In situ observation revealed that a state of pseudo-weightlessness was generated in the vicinity of the magnet bore edge, and small crystals were concentrated inside the domain moving along an hourglass-shaped surface. We found by numerical computations that the formation of the hourglass-shaped domain is attributable to the radial component of the magnetic force.

  19. A New Design Strategy for Observing Lithium Oxide Growth-Evolution Interactions Using Geometric Catalyst Positioning.

    PubMed

    Ryu, Won-Hee; Gittleson, Forrest S; Li, Jinyang; Tong, Xiao; Taylor, André D

    2016-08-10

    Understanding the catalyzed formation and evolution of lithium-oxide products in Li-O2 batteries is central to the development of next-generation energy storage technology. Catalytic sites, while effective in lowering reaction barriers, often become deactivated when placed on the surface of an oxygen electrode due to passivation by solid products. Here we investigate a mechanism for alleviating catalyst deactivation by dispersing Pd catalytic sites away from the oxygen electrode surface in a well-structured anodic aluminum oxide (AAO) porous membrane interlayer. We observe the cross-sectional product growth and evolution in Li-O2 cells by characterizing products that grow from the electrode surface. Morphological and structural details of the products in both catalyzed and uncatalyzed cells are investigated independently from the influence of the oxygen electrode. We find that the geometric decoration of catalysts far from the conductive electrode surface significantly improves the reaction reversibility by chemically facilitating the oxidation reaction through local coordination with PdO surfaces. The influence of the catalyst position on product composition is further verified by ex situ X-ray photoelectron spectroscopy and Raman spectroscopy in addition to morphological studies. PMID:27326464

  20. Sonographic Growth Charts for Kidney Length in Normal Korean Children: a Prospective Observational Study

    PubMed Central

    2016-01-01

    Kidney length is the most useful parameter for clinical measurement of kidney size, and is useful to distinguish acute kidney injury from chronic kidney disease. In this prospective observational study of 437 normal children aged between 0 and < 13 years, kidney length was measured using sonography. There were good correlations between kidney length and somatic values, including age, weight, height, and body surface area. The rapid growth of height during the first 2 years of life was intimately associated with a similar increase in kidney length, suggesting that height should be considered an important factor correlating with kidney length. Based on our findings, the following regression equation for the reference values of bilateral kidney length for Korean children was obtained: kidney length of the right kidney (cm) = 0.051 × height (cm) + 2.102; kidney length of the left kidney (cm) = 0.051 × height (cm) + 2.280. This equation may aid in the diagnosis of various kidney disorders. PMID:27366007

  1. Preschool Children's Explanations of Plant Growth and Rain Formation: A Comparative Analysis

    NASA Astrophysics Data System (ADS)

    Christidou, Vasilia; Hatzinikita, Vassilia

    2006-09-01

    This paper explores the different types and characteristics of preschool children's explanations of plant growth and rain formation. The children's explanations were categorized as naturalistic, non-naturalistic, or synthetic, i.e., explanations containing both naturalistic and non-naturalistic parts. In regards to plant growth the children tended to rely on synthetic or on naturalistic explanations, which involved direct and indirect agents (such as water, a person, fertilizers, roots) enabling the plant to grow. Non-naturalistic explanations of plant growth, or the non-naturalistic parts of synthetic explanations, were mainly animistic (anthropomorphic). In the case of rain formation the children most frequently used non-naturalistic explanations, which were mainly teleological or metaphysical. The naturalistic explanations recorded on rain formation, as well as the naturalistic parts of synthetic explanations tended to have a non-agentive character, i.e., children considered rainwater as preexisting in containers such as the clouds. Overall, the explanations recorded about plant growth tended to be more complex than the ones for rain formation. It is suggested that science activities designed for preschool children should take into account the types and characteristics of their explanations in order to select which phenomena are appropriate for this age group, and aim at fostering the children's ability at formulating naturalistic explanations.

  2. Comparative effects of constant versus fluctuating thermal regimens on yellow perch growth, feed conversion and survival

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of fluctuating or constant thermal regimens on growth, mortality, and feed conversion were determined for juvenile yellow perch (Perca flavescens). Yellow perch averaging 156mm total length and 43g body weight were held in replicate 288L circular tanks for 129 days under: 1) a diel therm...

  3. Comparative growth and toxin profile of cultured Ostreopsis ovata from the Tyrrhenian and Adriatic Seas.

    PubMed

    Guerrini, Franca; Pezzolesi, Laura; Feller, Andrea; Riccardi, Manuela; Ciminiello, Patrizia; Dell'Aversano, Carmela; Tartaglione, Luciana; Dello Iacovo, Emma; Fattorusso, Ernesto; Forino, Martino; Pistocchi, Rossella

    2010-01-01

    Massive blooms of the benthic dinoflagellate Ostreopsis ovata Fukuyo have recently occurred along the whole Italian coastlines, both Tyrrhenian and Adriatic, resulting sometimes in benthonic biocenosis sufferings and, occasionally, in human health problems. In this work, two strains of O. ovata collected in 2006 along the Adriatic and Tyrrhenian coastlines and grown in culture were studied to characterize their growth and toxin profile. The two strains showed different cell volumes, the Adriatic strain being nearly twice bigger than the Tyrrhenian, but they had similar slow growth rates. Liquid chromatography-mass spectrometry (LC-MS) analyses indicated that both strains produce putative palytoxin (pPLTX) and ovatoxin-a (OVTX-a), a palytoxin-like compound presenting 2 oxygen atoms less than palytoxin. Toxin content was determined at the end of the stationary and exponential growth phases and reached the highest value in the Adriatic strain at the end of the stationary phase, with concentrations of 353.3 microg l(-1) for OVTX-a and 30.4 microg l(-1) for pPLTX. Toxin released in the growth medium was also measured and resulted to be the highest at the end of the stationary phase, suggesting that a long lasting bloom could enhance the toxin content in the water and cause toxic effects in people inhaling the aerosol. PMID:19638281

  4. Comparative growth of Spring-planted canola, brown mustard and camelina

    Technology Transfer Automated Retrieval System (TEKTRAN)

    With increased emphasis for diesel substitution, production of brown mustard (Brassica juncea), canola (B. napus) and camelina (Camelina sativa) used as biodiesel may increase in the High Plains. The objective was to elucidate the growth pattern of these crops when spring-planted in western Nebraska...

  5. Comparative growth of trichoderma strains in different nutritional sources, using bioscreen c automated system

    PubMed Central

    Rossi-Rodrigues, Bianca Caroline; Brochetto-Braga, Márcia Regina; Tauk-Tornisielo, Sâmia Maria; Carmona, Eleonora Cano; Arruda, Valeska Marques; Chaud Netto, José

    2009-01-01

    Trichoderma is one of the fungi genera that produce important metabolites for industry. The growth of these organisms is a consequence of the nutritional sources used as also of the physical conditions employed to cultivate them. In this work, the automated Bioscreen C system was used to evaluate the influence of different nutritional sources on the growth of Trichoderma strains (T. hamatum, T. harzianum, T. viride, and T. longibrachiatum) isolated from the soil in the Juréia-Itatins Ecological Station (JIES), São Paulo State - Brazil. The cultures were grown in liquid culture media containing different carbon- (2%; w/v) and nitrogen (1%; w/v) sources at 28ºC, pH 6.5, and agitated at 150 rpm for 72 h. The results showed, as expected, that glucose is superior to sucrose as a growth-stimulating carbon source in the Trichoderma strains studied, while yeast extract and tryptone were good growth-stimulating nitrogen sources in the cultivation of T. hamatum and T. harzianum. PMID:24031380

  6. Comparative Studies of Community Growth. Rural Sociological Society Monograph No. 2.

    ERIC Educational Resources Information Center

    Young, Frank W.; Young, Ruth C.

    Studies pertaining to community growth have dealt with the community's territorial expansion, economy, government's functions, and institutions. Since researchers usually use the dimension that they have been taught (economists use economic measures, and social scientists use sociological measures), two problems have resulted: (1) How should…

  7. In Situ TEM Observations on the Sulfur-Assisted Catalytic Growth of Single-Wall Carbon Nanotubes.

    PubMed

    Zhang, Lili; Hou, Peng-Xiang; Li, Shisheng; Shi, Chao; Cong, Hong-Tao; Liu, Chang; Cheng, Hui-Ming

    2014-04-17

    The effect of sulfur on the catalytic nucleation and growth of single-wall carbon nanotubes (SWCNTs) from an iron catalyst was investigated in situ by transmission electron microscopy (TEM). The catalyst precursor of ferrocene and growth promoter of sulfur were selectively loaded inside of the hollow core of multiwall CNTs with open ends, which served as a nanoreactor powered by applying a voltage inside of the chamber of a TEM. It was found that a SWCNT nucleated and grew perpendicularly from a region of the catalyst nanoparticle surface, instead of the normal tangential growth that occurs with no sulfur addition. Our in situ TEM observation combined with CVD growth studies suggests that sulfur functions to promote the nucleation and growth of SWCNTs by forming inhomogeneous local active sites and modifying the interface bonding between catalysts and precipitated graphitic layers, so that carbon caps can be lifted off from the catalyst particle. PMID:26269989

  8. Comparative Study of Four Growth Models Applied to Weight and Height Growth Data in a Cohort of US Children from Birth to 9 Years

    PubMed Central

    Regnault, N.; Gillman, M. W.; Kleinman, K.; Rifas-Shiman, S.; Botton, J.

    2016-01-01

    Background/Aims The objective of our study was to compare the fit of four growth models for weight and height in contemporary US children between birth and 9 years. Methods In Project Viva, we collected weight and height growth data between birth and 9 years. We compared the Jenss model, the adapted Jenss model that adds a quadratic term, and the Reed 1st and 2nd order models. We used the log likelihood ratio test to compare nested models and the Akaike (AIC)/Bayesian information criterion (BIC) to compare nonnested models. Results For weight and height, the adapted Jenss model had a better fit than the Jenss model (for weight: p < 0.0001), and the Reed 2nd order model had a better fit than the Reed 1st order model (for weight: p < 0.0001). Compared with the Reed 2nd order model, the adapted Jenss model had a better fit for both weight (adapted Jenss vs. Reed 2nd order, AIC: 66,974 vs. 82,791, BIC: 67,066 vs. 82,883) and height (adapted Jenss vs. Reed 2nd order, AIC: 87,108 vs. 87,612, BIC: 87,196 vs. 87,700). Conclusions In this pre-birth study of children aged 0–9 years, for both weight and height the adapted Jenss model presented the best fit of all four tested models. PMID:25413655

  9. Chiropractic Use and Changes in Health among Older Medicare Beneficiaries: A Comparative Effectiveness Observational Study

    PubMed Central

    Weigel, Paula Anne; Hockenberry, Jason; Bentler, Suzanne; Wolinsky, Fredric D.

    2013-01-01

    Objective The purpose of this study was to investigate the effect of chiropractic on five outcomes among Medicare beneficiaries: increased difficulties performing Activities of Daily Living (ADLs), Instrumental ADLs (IADLs), and Lower Body Functions, as well as lower self-rated health and increased depressive symptoms. Methods Among all beneficiaries, we estimated the effect of chiropractic use on changes in health outcomes among those who used chiropractic compared to those who did not, and among beneficiaries with back conditions we estimated the effect of chiropractic use relative to medical care, both over a 2–15 year period. Two analytic approaches were used—one assumed no selection bias, while the other adjusted for potential selection bias using propensity score methods. Results Among all beneficiaries, propensity score analyses indicated that chiropractic use led to comparable outcomes for ADLs, IADLs, and depressive symptoms, although there were increased risks associated with chiropractic for declines in lower body function and self-rated health. Propensity score analyses among beneficiaries with back conditions indicated that chiropractic use led to comparable outcomes for ADLs, IADLs, lower body function, and depressive symptoms, although there was an increased risk associated with chiropractic use for declines in self-rated health. Conclusion The evidence in this study suggests that chiropractic treatment has comparable effects on functional outcomes when compared to medical treatment for all Medicare beneficiaries, but increased risk for declines in self-rated health among beneficiaries with back conditions. PMID:24144425

  10. Ionospheric simulation compared with Dynamics Explorer observations for November 22, 1981

    NASA Technical Reports Server (NTRS)

    Sojka, J. J.; Bowline, M.; Schunk, R. W.; Craven, J. D.; Frank, L. A.; Sharber, J. R.; Winningham, J. D.; Brace, L. H.

    1992-01-01

    The present study uses an extensive DE-2 data base to both constrain inputs to a time-dependent ionospheric model (TDIM) for a simulation of the ionosphere and then check the simulated densities. The investigation was carried out for both a quiet period and a substorm period. The quiet-day study produced very good agreement between modeled and observed electron densities in the topside ionosphere with two significant exceptions: First, across the polar region the DE-2 LANG densities showed fine structure in addition to the overall regional density morphology. Second, a surprising discrepancy arose in the presunrise and midlatitude trough. The TDIM densities were an order of magnitude lower than those observed by DE-2. The substorm study showed remarkably good agreement with the observed densities.