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Sample records for growth ring width

  1. Simulation of tree-ring widths with a model for primary production, carbon allocation, and growth

    NASA Astrophysics Data System (ADS)

    Li, G.; Harrison, S. P.; Prentice, I. C.; Falster, D.

    2014-12-01

    We present a simple, generic model of annual tree growth, called "T". This model accepts input from a first-principles light-use efficiency model (the "P" model). The P model provides values for gross primary production (GPP) per unit of absorbed photosynthetically active radiation (PAR). Absorbed PAR is estimated from the current leaf area. GPP is allocated to foliage, transport tissue, and fine-root production and respiration in such a way as to satisfy well-understood dimensional and functional relationships. Our approach thereby integrates two modelling approaches separately developed in the global carbon-cycle and forest-science literature. The T model can represent both ontogenetic effects (the impact of ageing) and the effects of environmental variations and trends (climate and CO2) on growth. Driven by local climate records, the model was applied to simulate ring widths during the period 1958-2006 for multiple trees of Pinus koraiensis from the Changbai Mountains in northeastern China. Each tree was initialised at its actual diameter at the time when local climate records started. The model produces realistic simulations of the interannual variability in ring width for different age cohorts (young, mature, and old). Both the simulations and observations show a significant positive response of tree-ring width to growing-season total photosynthetically active radiation (PAR0) and the ratio of actual to potential evapotranspiration (α), and a significant negative response to mean annual temperature (MAT). The slopes of the simulated and observed relationships with PAR0 and α are similar; the negative response to MAT is underestimated by the model. Comparison of simulations with fixed and changing atmospheric CO2 concentration shows that CO2 fertilisation over the past 50 years is too small to be distinguished in the ring-width data, given ontogenetic trends and interannual variability in climate.

  2. Simulation of tree ring-widths with a model for primary production, carbon allocation and growth

    NASA Astrophysics Data System (ADS)

    Li, G.; Harrison, S. P.; Prentice, I. C.; Falster, D.

    2014-07-01

    We present a simple, generic model of annual tree growth, called "T". This model accepts input from a first-principles light-use efficiency model (the P model). The P model provides values for Gross Primary Production (GPP) per unit of absorbed photosynthetically active radiation (PAR). Absorbed PAR is estimated from the current leaf area. GPP is allocated to foliage, transport-tissue, and fine root production and respiration, in such a way as to satisfy well-understood dimensional and functional relationships. Our approach thereby integrates two modelling approaches separately developed in the global carbon-cycle and forest-science literature. The T model can represent both ontogenetic effects (impact of ageing) and the effects of environmental variations and trends (climate and CO2) on growth. Driven by local climate records, the model was applied to simulate ring widths during 1958-2006 for multiple trees of Pinus koraiensis from the Changbai Mountain, northeastern China. Each tree was initialised at its actual diameter at the time when local climate records started. The model produces realistic simulations of the interannual variability in ring width for different age cohorts (young, mature, old). Both the simulations and observations show a significant positive response of tree-ring width to growing-season total photosynthetically active radiation (PAR0) and the ratio of actual to potential evapotranspiration (α), and a significant negative response to mean annual temperature (MAT). The slopes of the simulated and observed relationships with PAR0 and α are similar; the negative response to MAT is underestimated by the model. Comparison of simulations with fixed and changing atmospheric CO2 concentration shows that CO2 fertilization over the past 50 years is too small to be distinguished in the ring-width data given ontogenetic trends and interannual variability in climate.

  3. Ideas and perspectives: use of tree-ring width as an indicator of tree growth

    NASA Astrophysics Data System (ADS)

    Hember, R. A.; Kurz, W. A.; Metsaranta, J. M.

    2015-06-01

    By taking core samples, dendroecological studies can reconstruct radial growth over the lifespan of a tree, providing a valuable way to estimate the sensitivity of tree productivity to environmental change. With increasing prevalence of such studies in global change science, it is worth cautioning that the incremental growth rate of a sub-dimension of a tree organ, such as annual ring width (w), does not respond to extrinsic perturbations with the same relative magnitude as the primary production of that organ. For example, if an extrinsic force causes a two-fold increase in the absolute growth rate of stemwood biomass (AGR), it should only theoretically translate into a 1.3-fold increase in w, or a 1.7-fold increase in basal area increment (BAI), when a 2:1 ratio in resource allocation to lateral and apical meristems is assumed. Expressing the magnitude of a response in relative terms does not, therefore, provide a valid means of comparing estimates of relative growth derived from measurement of different dimensional traits of the tree. From our perspective, enough conformity to facilitate comparison of environmental sensitivity across studies of tree growth is warranted so we emphasize the benefit of dimension analysis to transform measurements of w and BAI into the AGR. Although conversion to AGR introduces an error from the use of allometric equations, the approach is widely accepted in mainstream ecology and global change science at least partially because it avoids discrepancies in response magnitude owing to differences in dimension. Studies of organ elongation have historically provided invaluable information, yet it must be recognized that they systematically underestimate the response magnitude of primary production, and confound comparisons of growth sensitivity between many dendroecological studies that focus on w and studies of primary production.

  4. Soil Warming and Fertilization Effects on Growth Ring Widths of Arctic Shrubs - Application of a Novel Dendroecological Approach.

    NASA Astrophysics Data System (ADS)

    Iturrate Garcia, M.; Heijmans, M.; Schweingruber, F. H.; Niklaus, P. A.; Schaepman-Strub, G.

    2015-12-01

    Climate warming is suggested as the main driver of shrub expansion in arctic tundra regions. Shrub expansion may have consequences on biodiversity and climate, especially through its feedbacks with the energy budget. A better understanding of shrub expansion mechanisms, including growth rate patterns and stem anatomy changes, and their sensitivity to climate is needed in order to quantify related feedbacks. We present a novel dendroecological approach to determine the response of three arctic shrub species to increased soil temperature and nutrients. A full factorial block-design experiment was run for four years with a total of thirty plots. Six individuals of each species were sampled from each plot to test for treatment effects on growth rate and stem anatomy. We compared the ring width of the four years of experiment with the one of the four previous years. The preliminary results for Betula nana and Salix pulchra suggest a significant effect of the treatments on the growth ring width. The response is stronger in Salix pulchra than in Betula nana individuals. And, while Salix pulchra is more sensitive to the combined soil warming and fertilization treatment, Betula nana is to the fertilization treatment. We could not observe an effect of treatment on the stem anatomy, likely because bark thickness co-varies with age. We found significant positive correlations of cork, cortex and phloem thickness with xylem thickness (used as a proxy of age), and a significant difference in stem anatomy between species. The results suggest species-specific growth sensitivity to soil warming and nutrient enhancement. The use of experimental dendroecology by manipulating environmental conditions according to future climate scenarios and testing effects on shrub anatomy and annual growth will increase our understanding on shrub expansion mechanisms. Ongoing plant trait analysis and consecutive application in a 3D radiative transfer model will allow to quantify the feedback of

  5. Tree growth inference and prediction from diameter censuses and ring widths

    Treesearch

    James S. Clark; Michael Wolosin; Michael Dietze; Ines Ibanez; Shannon LaDeau; Miranda Welsh; Brian Kloeppel

    2007-01-01

    Knowledge of tree growth is needed to understand population dynamics (Condit et al. 1993, Fastie 1995, Frelich and Reich 1995, Clark and Clark 1999, Wyckoff and Clark 2002, 2005, Webster and Lorimer 2005), species interactions (Swetnam and Lynch 1993), carbon sequestration (DeLucia et al. 1999, Casperson et al. 2000), forest response to climate change (Cook 1987,...

  6. Traffic pollution affects P. pinea growth according to tree ring width and C and N isotopic composition

    NASA Astrophysics Data System (ADS)

    Battipaglia, Giovanna; Marzaioli, Fabio; Lubritto, Carmine; Altieri, Simona; Strumia, Sandro; Cherubini, Paolo; Cotrufo, M. Francesca

    2010-05-01

    Urbanization and industrialization are rapidly growing, as a consequence roads and their associated vehicular traffic exerts major and increasing impacts on adjacent ecosystems. Various studies have shown the impact of vehicle exhausts on road side vegetation through their visible and non-visible effects (Farmer and Lyon 1977, Sarkar et al., 1986, Angold 1997, Nuhoglu 2005) but, presently there is little known about the long term effect of air pollution on vegetation and on trees, in particular. Developing proxies for atmospheric pollution that would be used to identify the physiological responses of trees under roadside car exhaust pollution stress is needed. In this context we propose a novel method to determine the effect of car exhaust pollution on tree growth, coupling classical dendrochronological analyses and analyses of 15N and 13C in tree rings, soils and leaves with tree ring radiocarbon (14C) data. Pinus pinea individuals, adjacent to main roads in the urban area of Caserta (South Italy) and exposed to large amounts of traffic exhausts since 1980, were sampled and the time-related trend in the growth residuals was estimated. We found a consistent decrease in the ring width starting from 1980, with a slight increase in δ13C value, which was considered to be a consequence of environmental stress. No clear pattern was identified in δ15N, while an increasing effect of the fossil fuel dilution on the atmospheric bomb-enriched 14C background was detected in tree rings, as a consequence of the increase in traffic exhausts. Our findings suggest that radiocarbon is a very sensitive tool to investigate small-scale (i.e. traffic exhaust at the level crossing) and large-scale (urban area pollution) induced disturbances. References Angold PG. Impact of a road upon adjacent heathland vegetations: effect on plant species compositions. J Appl Ecol 1997; 34 (2): 409-417. Farmer JC, Lyon TDB. Lead in Glasgow street dirt and soil. Sci Tot Environ 1977; 8: 89-93. Nuhoglu

  7. Some geometric constraints on ring-width trend

    USGS Publications Warehouse

    Phipps, R.L.

    2005-01-01

    Simulations of tree rings from trees of undisturbed forest sites are used to describe natural, long-term width trends. Ring-width trends of canopy-sized white oak are simulated from regressions of BAI (ring area) data of real trees. Examples are given of a tree from a typical re-growth forest in Illinois and of a more slowly growing tree from an old-growth forest in Kentucky. The long-term width trend was simulated as being toward constant ring width regardless of growth rate of the tree. Conditions by which either increasing or decreasing ring-width trends could be simulated from the same linear BAI trend are examined. I conclude that curvilinear width trends, either increasing or decreasing, represent width adjustments to changes in growth rate (BAI trend) after which the width trend stabilizes to a near-constant value. Interpretation of ring-width trends of trees from undisturbed stands may be useful in assessing stand disturbance history. Copyright ?? 2005 by the Tree-Ring Society.

  8. Pinus halepensis tree-ring widths at the periphery of the eastern Mediterranean forest growth as a possible proxy for recontruction of vegetation greeness.

    NASA Astrophysics Data System (ADS)

    Ababneh, L. N.

    2015-12-01

    The IPCC report (2014) signifies the importance of understanding the dynamic and elastic relationship between global climate change and forest growth as ramifications are still uncertain despite increased experimental efforts (IPCC 2014, Frank et al.,2015). Further, understanding and modeling this relationship is over emphasized in arid to semi-arid areas such as the Middle East where limited natural resources have proven record of correlation with conflict (e.g.Kelley et al., 2015). This work reports on the response of a forest stand of Pinus halepensis (Aleppo pine) from north Jordan to variability in precipitation using instrumental and satellite derived data. The site is located in north Jordan on the transitional zones from forest to steppe of the eastern Mediterranean as classified by the European Forest Genetic Resources Programme (EUFORGEN, 2015). The aim is to model the relationship between annual earlywood, latewood and tree-ring width indices with instrumental data, reanalysis data and Normalized Difference Vegetation Index (NDVI) in the period from 1976-2012 for a possible use of tree-ring widths as vegetation greenness proxy. The highest significant correlation (p< 0.005, α =0.05) is between current year's growth and prior spring precipitation (instrumental and reanalysis) and NDVI. Reanalysis data correlates significantly (p<0.005, α =0.05, r: 0.85) with instrumental data (1976-2012) but is limited by the records' length. There is definitely a proven correlation between seasonal tree-ring widths and vegetation index that offers the potential for reconstruction of vegetation index if applied at the regional level and could be extrapolated to desert areas that lacks proxy data with annually resolved resolution such as tree-rings.

  9. Radial widths, optical depths, and eccentricities of the Uranian rings

    NASA Astrophysics Data System (ADS)

    Nicholson, P. D.; Matthews, K.; Goldreich, P.

    1982-02-01

    Observations of the stellar occultation by the Uranian rings of 15/16 August 1980 are used to estimate radial widths and normal optical depths for segments of rings 6, 5, 4, alpha, beta, eta, gamma, and delta. Synthetic occultation profiles are generated to match the observed light curves. A review of published data confirms the existence of width-radius relations for rings alpha and beta, and indicates that the optical depths of these two rings vary inversely with their radial widths. Masses are obtained for rings alpha and beta, on the assumption that differential precession is prevented by their self-gravity. A quantitative comparison of seven epsilon-ring occultation profiles obtained over a period of 3.4 yr reveals a consistent structure, which may reflect the presence of unresolved gaps and subrings.

  10. The influence of masting phenomenon on growth-climate relationships in trees: explaining the influence of previous summers' climate on ring width.

    PubMed

    Hacket-Pain, Andrew J; Friend, Andrew D; Lageard, Jonathan G A; Thomas, Peter A

    2015-03-01

    Tree growth is frequently linked to weather conditions prior to the growing season but our understanding of these lagged climate signatures is still poorly developed. We investigated the influence of masting behaviour on the relationship between growth and climate in European Beech (Fagus sylvatica L.) using a rare long-term dataset of seed production and a new regional tree ring chronology. Fagus sylvatica is a masting species with synchronous variations in seed production which are strongly linked to the temperature in the previous two summers. We noted that the weather conditions associated with years of heavy seed production (mast years) were the same as commonly reported correlations between growth and climate for this species. We tested the hypothesis that a trade-off between growth and reproduction in mast years could be responsible for the observed lagged correlations between growth and previous summers' temperatures. We developed statistical models of growth based on monthly climate variables, and show that summer drought (negative correlation), temperature of the previous summer (negative) and temperature of the summer 2 years previous (positive) are significant predictors of growth. Replacing previous summers' temperature in the model with annual seed production resulted in a model with the same predictive power, explaining the same variance in growth. Masting is a common behaviour in many tree species and these findings therefore have important implications for the interpretation of general climate-growth relationships. Lagged correlations can be the result of processes occurring in the year of growth (that are determined by conditions in previous years), obviating or reducing the need for 'carry-over' processes such as carbohydrate depletion to be invoked to explain this climate signature in tree rings. Masting occurs in many tree species and these findings therefore have important implications for the interpretation of general climate-growth

  11. Anomalous dark growth rings in black cherry

    Treesearch

    Robert P. Long; David W. Trimpey; Michael C. Wiemann; Susan L. Stout

    2012-01-01

    Anomalous dark growth rings have been observed in black cherry (Prunus serotina) sawlogs from northwestern Pennsylvania making the logs unsuitable for veneer products. Thirty-six cross sections with dark rings, each traceable to one of ten stands, were obtained from a local mill and sections were dated and annual ring widths were measured. One or...

  12. On the Assimilation of Tree-Ring-Width Chronologies

    NASA Astrophysics Data System (ADS)

    Acevedo, Walter; Reich, Sebastian; Cubasch, Ulrich

    2015-04-01

    Data assimilation (DA) of climate proxy records is currently acknowledged as a promising approach to the paleoclimate reconstruction problem, with the potential to bring physical consistency to reconstructed fields. Previous paleo-DA studies have typically assumed a linear relationship between climate forcing and the resulting proxy data, whereas there exist growing evidence of complex, potentially non-linear, proxy formation processes. Accordingly, it appears natural to simulate the proxy response to climate in a more realistic fashion, by way of proxy-specific forward models. Following this train of thought, we investigate the assimilation of the most traditional climate proxy type, Tree-Ring-Width (TRW) chronologies, using the process-based tree-ring growth forward model Vaganov-Shashkin-Lite (VSL) and ensemble Kalman filter (EnKF) techniques. Used as observation operator, VSL's formulation implies three compounding, challenging features: (i) time averaging, (ii) "switching recording" of 2 variables and (iii) bounded response windows leading to "thresholded response". DA experiments involving VSL-based pseudo-TRW observations are performed first for a chaotic 2-scale dynamical system, used as a cartoon of the atmosphere-land system, and then for an atmospheric general circulation model of intermediate complexity. Our results reveal that VSL's nonlinearities may considerable deteriorate the performance of EnKF for Time-Averaged (TA) estimation, as compared to the utilization of a TA linear observation operator. Moreover, we show that this assimilation skill loss can be considerably reduced by embedding VSL's formulation into fuzzy logic theory, which fosters new interpretations of tree-ring growth limitation processes.

  13. Reconstructing Ecosystem-Scale Vegetation Activity Across the Terrestrial Mediterranean using Tree-Ring Width Data

    NASA Astrophysics Data System (ADS)

    Coulthard, B. L.; Touchan, R.; Meko, D. M.; Anchukaitis, K. J.; Sivrikaya, F.; Attalah, S.; Ilmen, R.; Aloui, A.; Attieh, J.; Mitsopoulos, I.; Sabir, M.; Christou, A.; Bozali, N.; Ketmen, M.; Stephan, J.

    2016-12-01

    Connecting radial tree-growth variables with remotely-sensed vegetation indices provides a foundation for using tree-rings as proxies for ecosystem primary productivity over large space and long time scales. Here we explore the association between tree-ring width and Normalized Difference Vegetation Index (NDVI) records across the Mediterranean. In contrast with most previous tree-ring/remote sensing studies, which have focused on temperature-limited boreal and taiga environments, we assess a large network of drought-sensitive tree-ring width chronologies as proxies for ecosystem-scale `greening', which in this region is largely controlled by moisture availability across vegetation cover types. We find that precipitation, elevation, and land-cover type interact to generate a statistical relationship between radial tree growth and NDVI. Specifically, tree-ring chronologies at low-elevation dry sites are strongly correlated with NDVI during the winter (maximum) precipitation season. In these settings land cover is dominated by grass- and shrublands, suggesting tree-ring width operates as a proxy for broader ecosystem-scale vegetation activity as captured by NDVI. Interactions between climate, geography, and land cover modify the extent to which tree-ring data and NDVI are linked across the Mediterranean, and may be capitalized upon to fine-tune spatial reconstructions of vegetation activity here and in other water-limited environments.

  14. Using ring width correlations to study the effects of plantation density on wood density and anatomical properties of red pine (Pinus resinosa Ait.)

    Treesearch

    J. Y. Zhu; C. T. Scott; K. L. Scallon; G. C. Myers

    2006-01-01

    This study demonstrated that average ring width (or average annual radial growth rate) is a reliable parameter to quantify the effects of tree plantation ndensity (growth suppression) on wood density and tracheid anatomical properties. The average ring width successfully correlated wood density and tracheid anatomical properties of red pines (Pinus resinosa Ait.) from...

  15. Tree-ring width reveals the preparation of the 1974 Mt. Etna eruption

    NASA Astrophysics Data System (ADS)

    Seiler, Ruedi; Houlié, Nicolas; Cherubini, Paolo

    2017-03-01

    Reduced near-infrared reflectance observed in September 1973 in Skylab images of the western flank of Mt. Etna has been interpreted as an eruption precursor of the January 1974 eruption. Until now, it has been unclear when this signal started, whether it was sustained and which process(es) could have caused it. By analyzing tree-ring width time-series, we show that the reduced near-infrared precursory signal cannot be linked to a reduction in annual tree growth in the area. However, comparing the tree-ring width time-series with both remote sensing observations and volcano-seismic activity enables us to discuss the starting date of the pre-eruptive period of the 1974 eruption.

  16. Tree-ring width reveals the preparation of the 1974 Mt. Etna eruption

    PubMed Central

    Seiler, Ruedi; Houlié, Nicolas; Cherubini, Paolo

    2017-01-01

    Reduced near-infrared reflectance observed in September 1973 in Skylab images of the western flank of Mt. Etna has been interpreted as an eruption precursor of the January 1974 eruption. Until now, it has been unclear when this signal started, whether it was sustained and which process(es) could have caused it. By analyzing tree-ring width time-series, we show that the reduced near-infrared precursory signal cannot be linked to a reduction in annual tree growth in the area. However, comparing the tree-ring width time-series with both remote sensing observations and volcano-seismic activity enables us to discuss the starting date of the pre-eruptive period of the 1974 eruption. PMID:28266610

  17. Correlation of bristlecone pine ring widths with atmospheric C-14 variations - A climate-sun relation

    NASA Astrophysics Data System (ADS)

    Sonett, C. P.; Suess, H. E.

    1984-01-01

    An unusually convincing correlation is shown between variations of cosmic ray-produced C-14 activity of the CO2 in the terrestrial atmosphere during the past five millenia and annual growth ring widths for bristlecone pine wood from Campito Mountain in eastern California. The correlation is based on power spectral densities (PSDs) and cross-covariance. The PSDs are computed using the maximum entropy method, and major spectral features are also confirmed using the Yule-Walker algorithm and the fast Fourier transform. The results suggest that a forcing function is present which mediates both the atmospheric C-14 level and tree growth.

  18. Tree-ring width based temperature and precipitation reconstruction in southeastern China

    NASA Astrophysics Data System (ADS)

    Shi, Jiangfeng; Shi, Shiyuan; Zhao, Yesi; Lu, Huayu

    2017-04-01

    Southeastern China is a subtropical region where the climate is dominated by the Asian monsoon climate system, with high temperature and precipitation in summer, and low temperature and precipitation in winter. Tree-ring research has been developed very fast in the past decade in the region. Some studies show that coniferous tree growth in the region is limited by temperatures in prior winter and during the growing season (i.e., prior November to current April, April to July, etc.), however to different limiting levels. Higher temperature in the dormant season means less damage to leaves and roots, and less consumption of previously stored carbohydrates and starches that can be used for tree growth in the coming year. The mechanism of positive relationships with the growing season is the same as that in high-latitude and high-elevation regions. The temperature reconstructions match each other very well at decadal to multi-decadal scales during the past 150 years at a large spatial scale, that is, of 700 km away, even though there are some discrepancies in the early part of the comparisons. Possible reasons for the discrepancies may include local temperature differences, small sample depth in the early part of the reconstructions, and/or juvenile effects. Generally, there is a weak precipitation signal in tree-ring width chronlogies. However, some studies have shown potentials in precipitation reconstruction in recent years, such as using tree-ring width chrnologies by taking samples at some special sites, using adjusted late-wood width chronlogies, and using stable isotopes. Thus, we might have a comprehensive understanding of the Asian monsson climate system over the past several centuries through temperature and precipitation reconstruction together using tree-ring series.

  19. Process based model sheds light on climate sensitivity of Mediterranean tree-ring width

    NASA Astrophysics Data System (ADS)

    Touchan, R.; Shishov, V. V.; Meko, D. M.; Nouiri, I.; Grachev, A.

    2012-03-01

    We use the process-based VS (Vaganov-Shashkin) model to investigate whether a regional Pinus halepensis tree-ring chronology from Tunisia can be simulated as a function of climate alone by employing a biological model linking day length and daily temperature and precipitation (AD 1959-2004) from a climate station to ring-width variations. We check performance of the model on independent data by a validation exercise in which the model's parameters are tuned using data for 1982-2004 and the model is applied to generate tree-ring indices for 1959-1981. The validation exercise yields a highly significant positive correlation between the residual chronology and estimated growth curve (r=0.76 p<0.0001, n=23). The model shows that the average duration of the growing season is 191 days, with considerable variation from year to year. On average, soil moisture limits tree-ring growth for 128 days and temperature for 63 days. Model results depend on chosen values of parameters, in particular a parameter specifying a balance ratio between soil moisture and precipitation. Future work in the Mediterranean region should include multi-year natural experiments to verify patterns of cambial-growth variation suggested by the VS model.

  20. Using Tree-Ring Width Data From 1000 Sites to Predict how American Forests Will Respond to Climate Change

    NASA Astrophysics Data System (ADS)

    Williams, P.; Still, C. J.; Leavitt, S. W.; Fischer, D. T.

    2007-12-01

    Beginning in the early 1900s, tree-ring scientists began analyzing the relative widths of annual growth rings preserved in the cross-sections of trees. Over the years, many ring-width index chronologies, each representing a specific site and species, have been developed and analyzed to infer details regarding past climate, growth response to environmental fluctuation, fire activity, logging practices by past societies, and more. Of the many ring-width chronologies constructed, 1035 represent sites within the continental United States and have been published online within The International Tree-Ring Data Bank as of September 2007 (ITRDB, http://www.ncdc.noaa.gov/paleo/treering.html). Approximately 85% of these sites are located west of the Mississippi River. Here we present results from a three-step study, using this large reserve of tree-growth data to determine how various tree species in various regions have responded to climate fluctuations in the past and how they can be expected to respond to future change. In the first step, we used linear regression to compare each time series of ring-width index values to a suite of local monthly climate variables that may influence tree growth, such as rainfall, temperature, and drought severity (PDSI). We identified the range of months (of a 24- month period) during which each climate parameter most strongly affects growth by comparing Pearson correlation coefficients. In the second step, we identified all sites where at least one climate parameter, during some rage of months, correlates significantly (95% confidence) with ring-width index values. For each of these sites, we constructed a growth model that uses each significantly correlating climate parameter as a growth predictor. In the third step, we applied the growth model to predict the next 100 years of growth response to a monthly climate forecast created by the Hadley Centre for Climate Prediction and Research. This forecast (HadCM3 IS92a) assumes a business as

  1. Climatic implications of a 3585-year tree-ring width chronology from the northeastern Qinghai-Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Shao, X.; Xu, Y.; Yin, Z.-Y.; Liang, E.; Zhu, H.; Wang, S.

    2010-08-01

    In this study we develop a tree-ring width chronology of Qilian juniper ( Sabina przewalskii Kom.) in the northeastern Qaidam Basin (northeastern Qinghai-Tibetan Plateau), China, which extends from 1580 BC to AD 2005 lasting 3585 years. This is by far the longest ring-width chronology in China. It is composed of archaeological wood samples from 13 sites, samples of living trees growing at a site with relatively good moisture condition and other long living trees from multiple sites approximately 100 m below the local upper treeline. Our results suggest that the archaeological wood and long living tree-ring width series belong to the same statistical population, which allows the construction of a single, regional composite chronology. We find that ring-width variations of the archaeological wood have statistical characteristics that are more similar to those trees from the lower part of the forest belt, where the moisture regime during the months at the onset of the growing season is the primary control on tree growth. Only after these analyses it becomes certain that the ring-width variations of the archaeological wood represent the variation of moisture conditions in the past. Therefore, the entire composite chronology is moisture-sensitive and suitable for reconstruction of the drought history and the related climate forcing over the past three millennia in the study region. The composite chronology shows considerable variations at inter-decadal to centennial timescales, with ten major multi-decadal low-growth periods corresponding to severe drought events in the past 2850 years, especially for two prominent events centered on AD 1480s and AD 1710s. On the other hand, significant high-growth periods were found centered on AD 590s and AD 1570s, and also in the past 30 years.

  2. Towards the assimilation of tree-ring-width records using ensemble Kalman filtering techniques

    NASA Astrophysics Data System (ADS)

    Acevedo, Walter; Reich, Sebastian; Cubasch, Ulrich

    2016-03-01

    This paper investigates the applicability of the Vaganov-Shashkin-Lite (VSL) forward model for tree-ring-width chronologies as observation operator within a proxy data assimilation (DA) setting. Based on the principle of limiting factors, VSL combines temperature and moisture time series in a nonlinear fashion to obtain simulated TRW chronologies. When used as observation operator, this modelling approach implies three compounding, challenging features: (1) time averaging, (2) "switching recording" of 2 variables and (3) bounded response windows leading to "thresholded response". We generate pseudo-TRW observations from a chaotic 2-scale dynamical system, used as a cartoon of the atmosphere-land system, and attempt to assimilate them via ensemble Kalman filtering techniques. Results within our simplified setting reveal that VSL's nonlinearities may lead to considerable loss of assimilation skill, as compared to the utilization of a time-averaged (TA) linear observation operator. In order to understand this undesired effect, we embed VSL's formulation into the framework of fuzzy logic (FL) theory, which thereby exposes multiple representations of the principle of limiting factors. DA experiments employing three alternative growth rate functions disclose a strong link between the lack of smoothness of the growth rate function and the loss of optimality in the estimate of the TA state. Accordingly, VSL's performance as observation operator can be enhanced by resorting to smoother FL representations of the principle of limiting factors. This finding fosters new interpretations of tree-ring-growth limitation processes.

  3. Traffic pollution affects tree-ring width and isotopic composition of Pinus pinea.

    PubMed

    Battipaglia, Giovanna; Marzaioli, Fabio; Lubritto, Carmine; Altieri, Simona; Strumia, Sandro; Cherubini, Paolo; Cotrufo, M Francesca

    2010-01-01

    This study presents new evidence that radiocarbon, combined with dendrochronological and stable isotopes analysis in tree rings and needles, can help to better understand the influence of pollution on trees. Pinus pinea individuals, adjacent to main roads in the urban area of Caserta (South Italy) and exposed to large amounts of traffic exhaust since 1980, were sampled and the time-related trend in the growth residuals was estimated. We found a consistent decrease in the ring width starting from 1980, with a slight increase in delta(13)C value, which was considered to be a consequence of environmental stress. No clear pattern was identified in delta(15)N, while an increasing effect of the fossil fuel dilution on the atmospheric bomb-enriched (14)C background was detected in tree rings, possibly as a consequence of the increase in traffic exhausts. Our findings suggested that radiocarbon is a very sensitive tool to investigate small-scale (i.e. traffic exhaust at the level crossing) and large-scale (urban area pollution) induced disturbances.

  4. Chronomics of climatic variations of tree ring width

    NASA Astrophysics Data System (ADS)

    Otsuka, K.; Cornélissen, G.; Halberg, F.

    2010-12-01

    Variations in the average annual tree rings of 11 sequoia trees for 2189 years are studied. The power spectrum of tree ring variations, calculated by the Maximum Entropy Method (MEM), is power-law in character with the coefficient β close to -1.00, suggesting the fractal character of the considered time series. The calculations of the coefficient β in a 200-year sliding window showed that this coefficient rapidly drops to zero or very small positive values, indicating a break in the fractal structure in some intervals. We identified seven such episodes, two (the latest) of which correspond to Spörer and Maunder solar minima. The other five episodes, which occurred around 100 BC and 500, 700, 820, and 880 AD, i.e., before regular sunspot observations, may also correspond to climate changes. By combining methods aimed at identifying the specific spectral components, such as the Schwabe cycle and behavior of the 1/ f dependence as a chaos characteristic, the chronobiologic (chronomics) approach can be used to study the global climatic processes—such as cycles of about 500 years—bearing on global warming.

  5. Continuing upward trend in Mt Read Huon pine ring widths - Temperature or divergence?

    NASA Astrophysics Data System (ADS)

    Allen, K. J.; Cook, E. R.; Buckley, B. M.; Larsen, S. H.; Drew, D. M.; Downes, G. M.; Francey, R. J.; Peterson, M. J.; Baker, P. J.

    2014-10-01

    To date, no attempt has been made to assess the presence or otherwise of the “Divergence Problem” (DP) in existing multi-millennial Southern Hemisphere tree-ring chronologies. We have updated the iconic Mt Read Huon pine chronology from Tasmania, southeastern Australia, to now include the warmest decade on record, AD 2000-2010, and used the Kalman Filter (KF) to examine it for signs of divergence against four different temperature series available for the region. Ring-width growth for the past two decades is statistically unprecedented for the past 1048 years. Although we have identified a decoupling between temperature and growth in the past two decades, the relationship between some of the temperature records and growth has varied over time since the start of instrumental records. Rather than the special case of ‘divergence', we have identified a more general time-dependence between growth and temperature over the last 100 years. This time-dependence appears particularly problematic at interdecadal time scales. Due to the time-dependent relationships, and uncertainties related to the climate data, the use of any of the individual temperature series examined here potentially complicates temperature reconstruction. Some of the uncertainty in the climate data may be associated with changing climatic conditions, such as the intensification of the sub-tropical ridge (STR) and its impact on the frequency of anticyclonic conditions over the Mt Read site. Increased growth at the site, particularly in the last decade, over and above what would be expected based on a linear temperature model alone, may be consistent with a number of hypotheses. Existing uncertainties in the climate data need to be resolved and independent physiological information obtained before a range of hypotheses for this increased growth can be effectively evaluated.

  6. Towards a common methodology to simulate tree mortality based on ring-width data

    NASA Astrophysics Data System (ADS)

    Cailleret, Maxime; Bigler, Christof; Bugmann, Harald; Davi, Hendrik; Minunno, Francesco; Peltoniemi, Mikko; Martínez-Vilalta, Jordi

    2015-04-01

    Individual mortality is a key process of population and community dynamics, especially for long-lived species such as trees. As the rates of vegetation background mortality and of massive diebacks accelerated during the last decades and would continue in the future due to rising temperature and increasing drought, there is a growing demand of early warning signals that announce that the likelihood of death is very high. If physiological indicators have a high potential to predict tree mortality, their development requires an intensive tree monitoring which cannot be currently done on a representative sample of a population and on several species. An easier approach is to use radial growth data such as tree ring-widths measurements. During the last decades, an increasing number of studies aimed to derive these growth-mortality functions. However, as they followed different approaches concerning the choice of the sampling strategy (number of dead and living trees), of the type of growth explanatory variables (growth level, growth trend variables…), and of the length of the time-window (number of rings before death) used to calculate them, it makes difficult to compare results among studies and a subsequent biological interpretation. We detailed a new methodology for assessing reliable tree-ring based growth-mortality relationships using binomial logistic regression models. As examples we used published tree-ring datasets from Abies alba growing in 13 different sites, and from Nothofagus dombeyi and Quercus petraea located in one single site. Our first approach, based on constant samplings, aims to (1) assess the dependency of growth-mortality relationships on the statistical sampling scheme used; (2) determine the best length of the time-window used to calculate each growth variable; and (3) reveal the presence of intra-specific shifts in growth-mortality relationships. We also followed a Bayesian approach to build the best multi-variable logistic model considering

  7. Development of narrow width type oil control ring for motorcycle engine

    SciTech Connect

    Tateishi, Yukio; Fujimura, Kazuhiro; Ishihara, Katsushi; Watanabe, Masanor

    1995-12-31

    The reduction of piston ring friction forces, which account for high percentages of the total engine friction loss, is vital for the simultaneous attainments of lower fuel consumption, higher engine power and speed. The authors et al. noted a three-piece type oil control ring in this study, and strived for the development of an oil control ring with a narrow width and a low tangential force. A new three-piece, type oil control ring with a small tolerance on tangential force and a width of 1.2 to 1.5 mm has been successfully developed by studying the effect of such a ring on the lubricating oil consumption, while providing a spring function by press-forming a wire rod having a particular sectional shape.

  8. Climate reconstructions from tree-ring widths for the last 850 years in Northern Poland

    NASA Astrophysics Data System (ADS)

    Heinrich, Ingo; Knorr, Antje; Heußner, Karl-Uwe; Wazny, Tomasz; Slowinski, Michal; Helle, Gerhard; Simard, Sonia; Scharnweber, Tobias; Buras, Allan; Beck, Wolfgang; Wilmking, Martin; Brauer, Achim

    2015-04-01

    Tree-ring based temperature reconstructions form the scientific backbone of the current debate over global change, and they are the major part of the palaeo data base used for the IPCC report. However, long temperature reconstructions derived from temperate lowland trees growing well within their distributional limits in central Europe are not part of the IPCC report, which is an essential gap in the international data base. It appears that dendroclimatological analysis at temperate lowland sites was so far difficult to perform mainly for three reasons: diffuse climate-growth relationships, the lack of long chronologies due to absence of sufficient numbers of long-living trees and the potential loss of low-frequency signals due to the short length of the sample segments. We present two robust multi-centennial reconstructions of winter temperatures and summer precipitation based on pine and oak tree-ring widths chronologies from northern Poland, where so far no long tree-ring based reconstructions were available. We compared the new records with global, hemispherical and regional reconstructions, and found good agreement with some of them. In comparison, the winter temperature of our reconstruction, however, did not indicate any modern warming nor did the summer precipitation reconstruction suggest any modern 20th century changes. In a second step, we measured cell structures and developed chronologies of parameters such as cell wall thickness and cell lumen area. We used our new method (Liang et al. 2013a,b) applying confocal laser scanning microscopy to increment core surfaces for efficient histometric analyses. We focused on samples covering the last century because meteorological data necessary for calibration studies were available for direct comparisons. It was demonstrated that the correlations with climate were strong and different from those found for tree-ring widths (e.g., N-Poland oak-vessel-lumen-area-chronology with previous September-to-December mean

  9. Reconstruction of Ob River, Russia, discharge from ring widths of floodplain trees

    NASA Astrophysics Data System (ADS)

    Agafonov, Leonid I.; Meko, David M.; Panyushkina, Irina P.

    2016-12-01

    The Ob is the third largest Eurasian river supplying heat and freshwater to the Arctic Ocean. These inputs influence water salinity, ice coverage, ocean temperatures and ocean circulation, and ultimately the global climate system. Variability of Ob River flow on long time scales is poorly understood, however, because gaged flow records are short. Eleven tree-ring width chronologies of Pinus sibirica and Larix sibirica are developed from the floodplain of the Lower Ob River, analyzed for hydroclimatic signal and applied as predictors in a regression model to reconstruct 8-month average (December-July) discharge of the Ob River at Salekhard over the interval 1705-2012 (308 yrs). Correlation analysis suggests the signal for discharge comes through air temperature: high discharge and floodplain water levels favor cool growing-season air temperature, which limits tree growth for the sampled species at these high latitudes. The reconstruction model (R2 = 0.31, 1937-2009 calibration period) is strongly supported by cross-validation and analysis of residuals. Correlation of observed with reconstructed discharge improves with smoothing. The long-term reconstruction correlates significantly with a previous Ob River reconstruction from ring widths of trees outside the Ob River floodplain and extends that record by another century. Results suggest that large multi-decadal swings in discharge have occurred at irregular intervals, that variations in the 20th and 21st centuries have been within the envelope of natural variability of the past 3 centuries, and that discharge data for 1937-2009 underestimate both the variability and persistence of discharge in the last 3 centuries. The reconstruction gives ecologists, climatologists and water resource planners a long-term context for assessment of climate change impacts.

  10. Assimilation of pseudo-tree-ring-width observations into an atmospheric general circulation model

    NASA Astrophysics Data System (ADS)

    Acevedo, Walter; Fallah, Bijan; Reich, Sebastian; Cubasch, Ulrich

    2017-05-01

    Paleoclimate data assimilation (DA) is a promising technique to systematically combine the information from climate model simulations and proxy records. Here, we investigate the assimilation of tree-ring-width (TRW) chronologies into an atmospheric global climate model using ensemble Kalman filter (EnKF) techniques and a process-based tree-growth forward model as an observation operator. Our results, within a perfect-model experiment setting, indicate that the "online DA" approach did not outperform the "off-line" one, despite its considerable additional implementation complexity. On the other hand, it was observed that the nonlinear response of tree growth to surface temperature and soil moisture does deteriorate the operation of the time-averaged EnKF methodology. Moreover, for the first time we show that this skill loss appears significantly sensitive to the structure of the growth rate function, used to represent the principle of limiting factors (PLF) within the forward model. In general, our experiments showed that the error reduction achieved by assimilating pseudo-TRW chronologies is modulated by the magnitude of the yearly internal variability in the model. This result might help the dendrochronology community to optimize their sampling efforts.

  11. North Patagonia climate over the last millennium inferred from variations in tree-ring width and isotopic composition

    NASA Astrophysics Data System (ADS)

    Lavergne, Aliénor; Villalba, Ricardo; Daux, Valérie

    2014-05-01

    To disentangle natural variability from man-induced climate changes, current climatic trends should be placed in a longer perspective. Tree-rings provide a wealth of information on past climates with high-resolution records covering up to thousands years. Recent tree-ring studies have highlighted the divergence phenomenon in Northern Hemisphere forests. At some temperature-limited northern sites, tree growth responses to climate during recent decades have changed, raising concerns about the quality of historical climate reconstructions based on tree-ring widths. This shift in the eco-physiological response of trees to climate has not yet been documented in the Southern Hemisphere. The aim of this study is to present the tree-ring evolution over the last centuries in northern Patagonia (southern South America; 41° 10'S-71° 50'W) in order to assess 1) divergence in tree-growth response to climate in recent decades, and 2) the potential of tree-ring parameters (width and δ18O) to reconstruct temperature and atmospheric circulation patterns such as the Southern Annular Mode (SAM). Based on quality and extent, instrumental temperature records across North Patagonia (39° -41° S) were selected for comparison with tree-ring records. Detection and correction of series inhomogeneities were conducted using HOMER software. A set of homogenized temperature data was developed for the period 1901-2013. Increment-borer samples from Fitzroya cupressoides and Nothofagus pumilio were collected along the regional precipitation gradient from the wet Valdivian rainforest to the mesic Patagonian forests during the austral summer of 2013. Six sampling sites (2 for Fitzroya, 4 for Nothofagus) along the gradient were established to maximize differences in tree-growth responses to climate and to assess the effect of precipitation on the responses. More than 500 cores were cross-dated, detrended and indexed. Composite tree-ring index (TRI) chronologies of F. cupressoides and N. pumilio

  12. Quantitative analysis of the tree-ring width record features essential for paleoclimatic reconstructions

    NASA Astrophysics Data System (ADS)

    Datsenko, N. M.; Ivashchenko, N. N.; Sonechkin, D. M.; Yang, B.

    2010-10-01

    Tree-ring width records provide a primary data source for millennial paleoclimatic reconstructions. However, a problem exists connected with taking into consideration the complex age-dependence within these records. Analyzing a set of very long-lived trees of Sabina przewalskii Kom. from the Dulan area of the northeastern Tibetan Plateau, we found for the first time that the annual basal-radius increment is larger for the outermost rings in comparison with the inner rings, especially for very long-living trees. Neglecting this circumstance when the so-called regional curve standardization is used can distort paleoclimatic reconstructions.

  13. Removing the tree-ring width biological trend using expected basal area increment

    Treesearch

    Franco Biondi; Fares Qeadan

    2008-01-01

    One of the main elements of dendrochronological standardization is the removal of the biological trend, i.e., the progressive decline of ring width along a cross-sectional radius that is mostly caused by the corresponding increase in stem diameter over time. A very common option for removing this biological trend is to fit a modified negative exponential curve to the...

  14. Micro - ring resonator with variety of gap width for acid rain sensing application: preliminary study

    NASA Astrophysics Data System (ADS)

    Mulyanti, B.; Ramza, H.; Pawinanto, R. E.; Rahman, J. A.; Ab-Rahman, M. S.; Putro, W. S.; Hasanah, L.; Pantjawati, A. B.

    2017-05-01

    The acid rain is an environmental disaster that it will be intimidates human life. The development micro-ring resonator sensor created from SOI (Silicon on insulator) and it used to detect acid rain index. In this study, the LUMERICAL software was used to simulate SOI material micro-ring resonator. The result shows the optimum values of fixed parameters from ring resonator have dependent variable in gap width. The layers under ring resonator with silicone (Si) and wafer layer of silicone material (Si) were added to seen three conditions of capability model. Model - 3 is an additional of bottom layer that gives the significant effect on the factor of quality. The optimum value is a peak value that given by the FSR calculation. FSR = 0, it means that is not shows the light propagation in the ring resonator and none of the light coming out on the bus - line.

  15. Measurement of annual ring width of log ends in forest machinery

    NASA Astrophysics Data System (ADS)

    Marjanen, Kalle; Ojala, Petteri; Ihalainen, Heimo

    2008-02-01

    The quality of wood is of increasing importance in wood industry. One important quality aspect is the average annual ring width and its standard deviation that is related to the wood strength and stiffness. We present a camera based measurement system for annual ring measurements. The camera system is designed for outdoor use in forest harvesters. Several challenges arise, such as the quality of cutting process, camera positioning and the light variations. In the freshly cut surface of log end the annual rings are somewhat unclear due to small splinters and saw marks. In the harvester the optical axis of camera cannot be set orthogonally to the log end causing non-constant resolution of the image. The amount of natural light in forest varies from total winter darkness to midsummer brightness. In our approach the image is first geometrically transformed to orthogonal geometry. The annual ring width is measured with two-dimensional power spectra. The two-dimensional power spectra combined with the transformation provide a robust method for estimating the mean and the standard deviation of annual ring width. With laser lighting the variability due to natural lighting can be minimized.

  16. Teasing Foggy Memories out of Pines on the California Channel Islands Using Tree-Ring Width and Stable Isotope Approaches

    NASA Astrophysics Data System (ADS)

    Williams, A. P.; Still, C. J.; Fischer, D. T.; Leavitt, S. W.

    2006-12-01

    The coast of California is home to many rare, endemic conifers and other plants that are not well adapted to the Mediterranean climate that prevails across most of the state. It has long been suggested that coastal pines survived the early-Pleistocene transition to a warmer and drier environment because they benefit from frequent fog and low stratus clouds that provide much needed water inputs and shading during the rainless summer. Here, we report evidence for the importance of this summer cloudiness to Torrey pines (Pinus torreyana) growing on Santa Rosa Island in Channel Islands National Park. We developed a tree-ring width chronology and quantified the relative importance of winter/spring precipitation and summer fog by comparing ring widths to nearby rainfall records and airport cloud-ceiling height data. While winter/spring precipitation explains most of the variation in annual tree-ring width (R2 = 0.592), the frequency of summertime fog correlated significantly and positively with annual ring width for 52 years of available fog data when the effect of winter/spring precipitation was removed (R2 = 0.118). The correlation between fog frequency and ring width decreased sharply when the range of possible cloud-ceiling heights deviated from the habitat range of the Torrey pine stand, emphasizing the importance of direct cloud immersion to these pines. In addition, the relationship between fog frequency and ring width was strongest in the 26 years that had enough winter/spring rainfall to maintain above-average soil moisture throughout the dry summer months (R2 = 0.312). This suggests that Torrey pines have an adaptive growing season length and that summer fog-water inputs are supplemental but not substantial enough to sustain tree growth independently. It may also be suggested that when summer growth does occur, the frequency of summer fog and stratus may govern growing season length. This made a "fog signal" difficult to detect in the stable isotope (carbon and

  17. Growth ring response in shortleaf pine following glaze icing conditions in western Arkansas and eastern Oklahoma

    Treesearch

    Douglas J. Stevenson; Thomas B. Lynch; James M. Guldin

    2013-01-01

    Width reduction in growth rings in shortleaf pine (Pinus echinata Mill.) following glaze ice conditions produces a characteristic pattern dependent on live-crown ratio and extent of crown loss. Ring widths of 133 trees for 3 years preceding and 7 years following the December 2000 ice storm (Bragg and others 2002) in western Arkansas and eastern...

  18. Alternative standardization approaches to improving streamflow reconstructions with ring-width indices of riparian trees

    USGS Publications Warehouse

    Meko, David M; Friedman, Jonathan M.; Touchan, Ramzi; Edmondson, Jesse R.; Griffin, Eleanor R.; Scott, Julian A.

    2015-01-01

    Old, multi-aged populations of riparian trees provide an opportunity to improve reconstructions of streamflow. Here, ring widths of 394 plains cottonwood (Populus deltoids, ssp. monilifera) trees in the North Unit of Theodore Roosevelt National Park, North Dakota, are used to reconstruct streamflow along the Little Missouri River (LMR), North Dakota, US. Different versions of the cottonwood chronology are developed by (1) age-curve standardization (ACS), using age-stratified samples and a single estimated curve of ring width against estimated ring age, and (2) time-curve standardization (TCS), using a subset of longer ring-width series individually detrended with cubic smoothing splines of width against year. The cottonwood chronologies are combined with the first principal component of four upland conifer chronologies developed by conventional methods to investigate the possible value of riparian tree-ring chronologies for streamflow reconstruction of the LMR. Regression modeling indicates that the statistical signal for flow is stronger in the riparian cottonwood than in the upland chronologies. The flow signal from cottonwood complements rather than repeats the signal from upland conifers and is especially strong in young trees (e.g. 5–35 years). Reconstructions using a combination of cottonwoods and upland conifers are found to explain more than 50% of the variance of LMR flow over a 1935–1990 calibration period and to yield reconstruction of flow to 1658. The low-frequency component of reconstructed flow is sensitive to the choice of standardization method for the cottonwood. In contrast to the TCS version, the ACS reconstruction features persistent low flows in the 19th century. Results demonstrate the value to streamflow reconstruction of riparian cottonwood and suggest that more studies are needed to exploit the low-frequency streamflow signal in densely sampled age-stratified stands of riparian trees.

  19. Determining the average annual ring width on the front side of lumber

    NASA Astrophysics Data System (ADS)

    Hanning, Tobias; Kickingereder, Reiner; Casasent, David

    2003-05-01

    Visual features of lumber can be used to assure its quality in stiffness and strength. Specifically, the average annual ring distance of the planks and the position of the center of the annual rings of the front side supply a close relation to some quality parameters of planks. Unfortunately, it turns out to be difficult to detect the average annual ring width by simple image vision methods due to distortions in the front side image of a plank caused by the cutting process. In this paper we propose two integrating methods which are capable of being used in an industrial application. One is based on quantizations of color images, the other on local Fourier transformations to detect the main wave in an image.

  20. 400+ Years of ENSO-like Climate Cyclicity from Tree Ring Width-Data, Wind River Range, Wyoming, USA.

    NASA Astrophysics Data System (ADS)

    Dahms, D. E.; Richards, D.; Pease, P.

    2014-12-01

    Spectral analysis of detrended ring-width data from a series of +400-year-old Douglas Firs on the SE flank of the Wind River Range indicates that tree growth from 1589-to-2013 shows a 2.5-to-4.5-year cyclicity (99%). This is within the limits of the generally accepted ~2-7 year ENSO cyclicity of the western Pacific. Our results also show a 16-year frequency (95%) suggesting possible additional influence from the Pacific Decadal Oscillation (PDO). Ring-widths here are most closely correlated to soil moisture conditions through the interaction(s) of abundant winter snowpack, summer rainfall, and average May-August temperatures during the 424-years from 1589-2013. Nearby climate records from the 1948-2013 period show that more favorable growth conditions exist here (higher snowpack+summer precipitation) during the El Niño cycle of ENSO. Our results fill a gap in knowledge of ENSO-like teleconnections during the Late Holocene that exists for the southern region of the Greater Yellowstone Ecosystem.

  1. Moisture-sensitive tree-ring widths from the Craters of the Moon lava-complex in east central, Idaho

    NASA Astrophysics Data System (ADS)

    Crawford, C. J.; Kipfmueller, K. F.; St George, S.

    2011-12-01

    Craters of the Moon (COM) National Monument is a basaltic volcanic complex on the eastern Snake River Plain that has formed over eight eruptive periods during the Holocene. Since the last eruption, limber pine (Pinus flexilis) and Douglas-fir (Pseudotsuga menziesii Mirb Franco.) have established on lava flows and ancient weathered cinder cones. These rare long-lived trees have survived for 400 - 1000 years on well-drained porous rock, inviting the possibility that tree-ring widths will show elevated moisture sensitivity. Four tree-ring records have been constructed from living trees and remnant wood that include limber pine total ring-width (937-2009 AD), Douglas-fir total ring-width, and partial earlywood and latewood widths (1468-2009 AD). During 1550-2009 AD, the covariance between records is moderately significant (0.31-0.34, p<0.01) for standard chronologies, but residual chronologies show little association (0.05-0.08). Monte-Carlo correlations between tree-ring widths and instrumental climate data (1930-2009) indicate that annual precipitation (prior Jun. - May) is correlated (p<0.01) with limber pine and Douglas-fir standard ring-width, and seasonal precipitation is correlated (p<0.01) with residual limber pine ring-width (prior Jul. - prior Dec.) and residual Douglas-fir earlywood width (Jan. - Jun). Because cool-season precipitation dominates the annual hydrological budget for the COM region, total ring-width persistence is primarily tuned to total annual precipitation while residual variance appears to reflect seasonal differences between the amount of prior fall - winter and winter - spring season moisture. So far, COM tree-ring records seem well suited as candidate predictors for paleoclimate reconstructions of not only annual precipitation, but also seasonally partitioned precipitation at interannual-decadal timescales.

  2. Ring Counts in Second-Growth Baldcypress

    Treesearch

    W. R. Beaufait; T. C. Nelson

    1957-01-01

    Many thrifty, second-growth baldcypress trees (Taxodium distichum) [L.] Rich. ) appear to lay down several rings each year. These false rings may cause foresters to underestimate the growth potential of a highly prized species by overestimating the age of sample trees.

  3. Water, gravity and trees: Relationship of tree-ring widths and total water storage dynamics

    NASA Astrophysics Data System (ADS)

    Creutzfeldt, B.; Heinrich, I.; Merz, B.; Blume, T.; Güntner, A.

    2012-04-01

    Water stored in the subsurface as groundwater or soil moisture is the main fresh water source not only for drinking water and food production but also for the natural vegetation. In a changing environment water availability becomes a critical issue in many different regions. Long-term observations of the past are needed to improve the understanding of the hydrological system and the prediction of future developments. Tree ring data have repeatedly proved to be valuable sources for reconstructing long-term climate dynamics, e.g. temperature, precipitation and different hydrological variables. In water-limited environments, tree growth is primarily influenced by total water stored in the subsurface and hence, tree-ring records usually contain information about subsurface water storage. The challenge is to retrieve the information on total water storage from tree rings, because a training dataset of water stored in the sub-surface is required for calibration against the tree-ring series. However, measuring water stored in the subsurface is notoriously difficult. We here present high-precision temporal gravimeter measurements which allow for the depth-integrated quantification of total water storage dynamics at the field scale. In this study, we evaluate the relationship of total water storage change and tree ring growth also in the context of the complex interactions of other meteorological forcing factors. A tree-ring chronology was derived from a Norway spruce stand in the Bavarian Forest, Germany. Total water storage dynamics were measured directly by the superconducting gravimeter of the Geodetic Observatory Wettzell for a 9-years period. Time series were extended to 63-years period by a hydrological model using gravity data as the only calibration constrain. Finally, water storage changes were reconstructed based on the relationship between the hydrological model and the tree-ring chronology. Measurement results indicate that tree-ring growth is primarily

  4. Boreal temperature variability inferred from maximum latewood density and tree-ring width data, Wrangell Mountain region, Alaska

    NASA Astrophysics Data System (ADS)

    Davi, Nicole K.; Jacoby, Gordon C.; Wiles, Gregory C.

    2003-11-01

    Variations in both width and density of annual rings from a network of tree chronologies were used to develop high-resolution proxies to extend the climate record in the Wrangell Mountain region of Alaska. We developed a warm-season (July-September) temperature reconstruction that spans A.D. 1593-1992 based on the first eigenvector from principal component analysis of six maximum latewood density (MXD) chronologies. The climate/tree-growth model accounts for 51% of the temperature variance from 1958 to 1992 and shows cold in the late 1600s-early 1700s followed by a warmer period, cooling in the late 1700s-early 1800s, and warming in the 20th century. The 20th century is the warmest of the past four centuries. Several severely cold warm-seasons coincide with major volcanic eruptions. The first eigenvector from a ring-width (RW) network, based on nine chronologies from the Wrangell Mountain region (A.D. 1550-1970), is correlated positively with both reconstructed and recorded Northern Hemisphere temperatures. RW shows a temporal history similar to that of MXD by increased growth (warmer) and decreased growth (cooler) intervals and trends. After around 1970 the RW series show a decrease in growth, while station data show continued warming, which may be related to increasing moisture stress or other factors. Both the temperature history based on MXD and the growth trends from the RW series are consistent with well-dated glacier fluctuations in the Wrangell Mountains and some of the temperature variations also correspond to variations in solar activity.

  5. Multicentury Reconstruction of Precipitations (1300-2014) in Eastern Canada from Tree-Ring Width and Carbon and Oxygen Isotopes

    NASA Astrophysics Data System (ADS)

    Giguère, Claudie; Boucher, Étienne; Bergeron, Yves

    2016-04-01

    Tree ring series enabling long hydroclimatic reconstructions are scarce in Northeastern America, mostly because most boreal species are rather thermo-dependant. Here we propose a new multi-proxy analysis (tree-ring, δ13C and δ18O) from one of the oldest Thuja occidentalis population in NE America (lake Duparquet, Quebec). These rare precipitation-sensitive, long-living trees (> 800 years) grow on xeric rocky shores and their potential for paleo-hydroclimatic reconstructions (based on ring widths solely) was previously assessed. The objectives of this study are twofold i) to strengthen the hydroclimatic signal of this long tree-ring chronology by adding analysis of stable isotope ratios (δ13C and δ18O) and ii) to reconstruct summer precipitation back to 1300 AD, which will represent, by far, the longest high-resolution hydroclimatic reconstruction in this region. A tree-ring chronology was constructed from 61 trees sampled in standing position. Eleven trees were also sampled to produce pooled carbon and oxygen isotope chronologies (annually resolved) with a replication of five to six trees per year. Signal analysis (correlation between climatic data and proxy values) confirms that growth is positively influenced by spring precipitations (May-June), while δ13C is negatively correlated to summer precipitation (June to August) and positively to June temperature. Adding δ18O analysis will strengthen the signal even more, since wood cellulose should be enriched in δ18O when high evapotranspiration conditions prevail. Based on a multi-proxy approach, a summer precipitation reconstruction was developed and compared to other temperature reconstructions from this region as well as to southernmost hydroclimatic reconstructions (e.g. Cook et al). A preliminary analysis of external and internal forcing is proposed in conclusion.

  6. Towards a common methodology for developing logistic tree mortality models based on ring-width data.

    PubMed

    Cailleret, Maxime; Bigler, Christof; Bugmann, Harald; Camarero, Jesús Julio; Cˇufar, Katarina; Davi, Hendrik; Mészáros, Ilona; Minunno, Francesco; Peltoniemi, Mikko; Robert, Elisabeth M R; Suarez, María Laura; Tognetti, Roberto; Martínez-Vilalta, Jordi

    2016-09-01

    Tree mortality is a key process shaping forest dynamics. Thus, there is a growing need for indicators of the likelihood of tree death. During the last decades, an increasing number of tree-ring based studies have aimed to derive growth-mortality functions, mostly using logistic models. The results of these studies, however, are difficult to compare and synthesize due to the diversity of approaches used for the sampling strategy (number and characteristics of alive and death observations), the type of explanatory growth variables included (level, trend, etc.), and the length of the time window (number of years preceding the alive/death observation) that maximized the discrimination ability of each growth variable. We assess the implications of key methodological decisions when developing tree-ring based growth-mortality relationships using logistic mixed-effects regression models. As examples, we use published tree-ring datasets from Abies alba (13 different sites), Nothofagus dombeyi (one site), and Quercus petraea (one site). Our approach is based on a constant sampling size and aims at (1) assessing the dependency of growth-mortality relationships on the statistical sampling scheme used, (2) determining the type of explanatory growth variables that should be considered, and (3) identifying the best length of the time window used to calculate them. The performance of tree-ring-based mortality models was reasonably high for all three species (area under the receiving operator characteristics curve, AUC > 0.7). Growth level variables were the most important predictors of mortality probability for two species (A. alba, N. dombeyi), while growth-trend variables need to be considered for Q. petraea. In addition, the length of the time window used to calculate each growth variable was highly uncertain and depended on the sampling scheme, as some growth-mortality relationships varied with tree age. The present study accounts for the main sampling-related biases to

  7. Validation of annual growth rings in freshwater mussel shells using cross dating .Can

    Treesearch

    Andrew L. Rypel; Wendell R. Haag; Robert H. Findlay

    2009-01-01

    We examined the usefulness of dendrochronological cross-dating methods for studying long-term, interannual growth patterns in freshwater mussels, including validation of annual shell ring formation. Using 13 species from three rivers, we measured increment widths between putative annual rings on shell thin sections and then removed age-related variation by...

  8. Solar and climate signal records in tree ring width from Chile (AD 1587 1994)

    NASA Astrophysics Data System (ADS)

    Rodolfo Rigozo, Nivaor; Roger Nordemann, Daniel Jean; Evangelista da Silva, Heitor; Pereira de Souza Echer, Mariza; Echer, Ezequiel

    2007-01-01

    Tree growth rings represent an important natural record of past climate variations and solar activity effects registered on them. We performed in this study a wavelet analysis of tree ring samples of Pilgerodendron cupressoides species, from Glaciar Pio XI (Lat: 49°12'S; 74°55'W; Alt: 25 m), Chile. We obtained an average chronology of about 400 years from these trees. The 11-yr solar cycle was present during the whole period in tree ring data, being more intense during Maunder minimum (1645-1715). The short-term periods, around 2-7 yr, that were found are more likely associated with ENSO effects. Further, we found significant periods around 52 and 80-100 yr. These periodicities are coincident with the fourth harmonic (52 yr) of the Suess cycle (208 yr) and Gleissberg (˜80-100 yr) solar cycles. Therefore, the present analysis shows evidence of solar activity effect/modulation on climatic conditions that affect tree ring growth. Although we cannot say with the present analysis if this effect is on local, regional or global climate, these results add evidence to an important role of solar activity over terrestrial climate over the past ˜400 yr.

  9. Inferring long-term carbon sequestration from tree rings at Harvard Forest: A calibration approach using tree ring widths and geochemistry / flux tower data

    NASA Astrophysics Data System (ADS)

    Belmecheri, S.; Maxwell, S.; Davis, K. J.; Alan, T. H.

    2012-12-01

    Improving the prediction skill of terrestrial carbon cycle models is important for reducing the uncertainties in global carbon cycle and climate projections. Additional evaluation and calibration of carbon models is required, using both observations and long-term proxy-derived data. Centennial-length data could be obtained from tree-rings archives that provide long continuous series of past forest growth changes with accurate annual resolution. Here we present results from a study conducted at Harvard Forest (Petersham, Massachusetts). The study examines the potential relationship between δ13C in dominant trees and GPP and/or NEE measured by the Harvard Forest flux tower (1992-2010). We have analyzed the δ13C composition of late wood-cellulose over the last 18 years from eastern hemlock (Tsuga canadensis) and northern red oak (Quercus rubra) trees growing in the flux tower footprint. δ13C values, corrected for the declining trend of atmospheric δ13C, show a decreasing trend from 1992 to 2010 and therefore a significant increase in discrimination (Δ). The intra-cellular CO2 (Ci) calculated from Δ shows a significant increase for both tree species and follows the same rate of atmospheric CO2 (Ca) increase (Ci/Ca increases). Interestingly, the net Ci and Δ increase observed for both species did not result in an increase of the iWUE. Ci/Ca is strongly related to the growing season Palmer Drought Severity Index (PDSI) for both species thus indicating a significant relationship between soil moisture conditions and stomatal conductance. The Ci trend is interpreted as a result of higher CO2 assimilation in response to increasing soil moisture allowing a longer stomata opening and therefore stimulating tree growth. This interpretation is consistent with the observed increase in GPP and the strengthening of the carbon sink (more negative NEE). Additionally, the decadal trends of basal area increment (BAI) calculated from tree-ring widths exhibit a positive trend over

  10. Global surface temperature signals in pine ring-width chronologies from southern monsoon Asia

    NASA Astrophysics Data System (ADS)

    Buckley, B. M.; Cook, B. I.; Bhattacharyya, A.; Dukpa, D.; Chaudhary, V.

    2005-10-01

    We analyze Pinus ring width chronologies from three locations across monsoon Asia (Bhutan, India, and Thailand) where climate is dominated by the southwest monsoon in the boreal summer. We compare these records to global surface temperatures for the past 150 years, shifting the correlations through three seasonal averages: two seasons preceding the monsoon (Dec-Feb and Mar-May), and the monsoon season itself (Jun-Sep). Clear patterns emerge for each of the chronologies that highlight links to areas of known influence on the Asian monsoon: the Indian Ocean, the tropical eastern Pacific Ocean, and the high-latitude Asian landmass. The Thai and Indian chronologies are from the same species (P. merkusii), and show a strong correlation with tropical Indian and Pacific Ocean bands. The Bhutan chronology (P. Wallichiana) is most strongly linked to climate over the north Pacific and Asian landmass. All of these correlations are strongest in seasons preceding the summer monsoon.

  11. Tree-ring widths are good proxies of annual variation in forest productivity in temperate forests.

    PubMed

    Xu, Kai; Wang, Xiangping; Liang, Penghong; An, Hailong; Sun, Han; Han, Wei; Li, Qiaoyan

    2017-05-16

    Tree rings have long been used to calibrate the net primary production (NPP) time-series predicted by process-based models, based on an implicit assumption that ring-width indices (RWI) can well reflect temporal NPP change. However, this assumption has seldom been tested systematically. In this study, 36 plots were set in three forest types from four sites along a latitudinal gradient in northeast China. For each plot, we constructed chronologies and stand NPP of the past 20 years to examine: is RWI a good proxy of inter-annual variation of forest NPP for different forest types under different climate? If it is, why? Our results indicate that RWI was closely related to stand NPP in most cases, and could be used as a good proxy of NPP in temperate forests. Standard and arstan chronologies were better related to NPP series than residual chronology. Stand NPP time-series were mainly determined by large trees, and the correlation between RWI and NPP was also higher for larger trees. We suggest that large trees and dominant species of canopy layer should be sampled for chronology construction. Large trees are major contributors of forest biomass and productivity, and should have priority in forest conservation in a rapid-warming world.

  12. Relating ring width of Mediterranean evergreen species to seasonal and annual variations of precipitation and temperature

    NASA Astrophysics Data System (ADS)

    Nijland, W.; Jansma, E.; Addink, E. A.; Domínguez Delmás, M.; de Jong, S. M.

    2011-05-01

    Plant growth in Mediterranean landscapes is limited by the typical summer-dry climate. Forests in these areas are only marginally productive and may be quite susceptible to modern climate change. To improve our understanding of forest sensitivity to annual and seasonal climatic variability, we use tree-ring measurements of two Mediterranean evergreen tree species: Quercus ilex L. and Arbutus unedo L. We sampled 34 stems of these species on three different types of substrates in the Peyne study area in southern France. The resulting chronologies were analysed in combination with 38 yr of monthly precipitation and temperature data to reconstruct the response of stem growth to climatic variability. Results indicate a strong positive response to May and June precipitation, as well as a significant positive influence of early-spring temperatures and a negative growth response to summer heat. Comparison of the data with more detailed productivity measurements in two contrasting years confirms these observations and shows a strong productivity limiting effect of low early-summer precipitation. The results show that tree-ring data from Q.ilex and A.unedo can provide valuable information about the response of these tree species to climate variability, improving our ability to predict the effects of climate change in Mediterranean ecosystems.

  13. Relating ring width of Mediterranean evergreen species to seasonal and annual variations of precipitation and temperature

    NASA Astrophysics Data System (ADS)

    Nijland, W.; Jansma, E.; Addink, E. A.; Domínguez Delmás, M.; de Jong, S. M.

    2011-01-01

    Plant growth in Mediterranean landscapes is limited by the typical summer-dry climate. Forests in these areas are only marginally productive and may be quite susceptible to modern climate change. To improve our understanding of forest sensitivity to annual and seasonal climatic variability, we use tree-ring measurements of two Mediterranean evergreen tree species: Quercus ilex and Arbutus unedo. We sampled 34 stems of these species on three different types of substrates in the Peyne study area in Southern France. The resulting chronologies were analysed in combination with 38 years of monthly precipitation and temperature data to reconstruct the response of stem growth to climatic variability. Results indicate a strong positive response to May and June precipitation, as well as a significant positive influence of early-spring temperatures and a negative growth response to summer heat. Comparison of the data with more detailed productivity measurements in two contrasting years confirms these observations and shows a strong productivity limiting effect of low early-summer precipitation. The results show that tree-ring data from Q. ilex and A. unedo can provide valuable information about the response of these tree species to climate variability, improving our ability to predict the effects of climate change in Mediterranean ecosystems.

  14. Lignin staining ...a limited success in identifying koa growth rings

    Treesearch

    Herbert L. Wick

    1970-01-01

    Among the lignin stains tested in trying to identify growth rings in koa (Acacia koa Gray), phloroglucinol was the most effective. The light colored sapwood of mature trees stained readily, with growth rings apparent. But staining failed to emphasize rings in the dark colored heartwood. Growth rings were not apparent on samples from young fast...

  15. Paleo Data Assimilation of Pseudo-Tree-Ring-Width Chronologies in a Climate Model

    NASA Astrophysics Data System (ADS)

    Fallah Hassanabadi, B.; Acevedo, W.; Reich, S.; Cubasch, U.

    2016-12-01

    Using the Time-Averaged Ensemble Kalman Filter (EnKF) and a forward model, we assimilate the pseudo Tree-Ring-Width (TRW) chronologies into an Atmospheric Global Circulation model. This study investigates several aspects of Paleo-Data Assimilation (PDA) within a perfect-model set-up: (i) we test the performance of several forward operators in the framework of a PDA-based climate reconstruction, (ii) compare the PDA-based simulations' skill against the free ensemble runs and (iii) inverstigate the skill of the "online" (with cycling) DA and the "off-line" (no-cycling) DA. In our experiments, the "online" (with cycling) PDA approach did not outperform the "off-line" (no-cycling) one, despite its considerable additional implementation complexity. On the other hand, it was observed that the error reduction achieved by assimilating a particular pseudo-TRW chronology is modulated by the strength of the yearly internal variability of the model at the chronology site. This result might help the dendrochronology community to optimize their sampling efforts.

  16. Tree Growth Rings: What They Tell Us.

    ERIC Educational Resources Information Center

    Sunal, Dennis W.; Sunal, Cynthia Szymanski

    1991-01-01

    Activities in which students can learn to determine the history of a tree from the growth pattern recorded in the rings of a cross-section of a tree are described. Activities include background information, objectives, a list of needed materials per group, and procedures. Cross-sections of four different tree types are included if real tree…

  17. Tree-ring model interprets growth decline in natural stands of loblolly pine in the southeastern United States

    Treesearch

    Robert Zahner; Joseph R. Saucier; Richard K. Myers

    1989-01-01

    Annual ring widths and ring areas from 131 even-aged, natural, well-stocked stands of loblolly pine (Pinus taeda L.) in the Piedmont region were analyzed to reveal possible causes of a previously reported decline in radial growth. A linear aggregate model was used to separate independent factors that are known to contribute to radial growth variation...

  18. Tree-ring model interprets growth decline in natural stands of loblolly pine in the southeastern United States

    Treesearch

    Robert Zahner; Joseph R. Saucier; Richard K. Myers

    1988-01-01

    Annual ring widths and ring areas from 131 even-aged, natural, well-stocked stands of loblolly pine (Pinus taeda L.) in the Piedmont region were analyzed to reveal possible causes of a previously reported decline in radial growth. A linear aggregate model was used to separate independent factors that are known to contribute to radial growth variation in this species....

  19. Reconstruction of Soil Moisture and Vegetation Water Use Conditions Based on Tree-Ring Widths From Qilian Juniper in Qaidam Basin, Northwestern China

    NASA Astrophysics Data System (ADS)

    Yin, Z.; Shao, X.; Liang, E.; Qin, N.

    2005-12-01

    Tree-ring widths have been used widely in studies of environmental changes and reconstructions of past climate. Eleven tree-ring chronologies of approximately 800-1500 years long were developed from Qilian juniper (Sabina przewalskii Kom.) for the eastern part of the Qaidam Basin, northwestern China. The study area is located in an arid/semi-arid region with desert and dry grassland vegetation, but sparse juniper trees can be found on mountain slopes of 3600-4200 m above sea level, along the northeastern margin of the Tibetan Plateau. Previous studies have revealed that ring widths are positively correlated to May and June precipitation, but negatively correlated to temperature of the same months in this region, indicating that water use stress is the most limiting factor for tree growth during the growing season. We performed water balance modeling based on 1955-2002 meteorological data. We found that the tree-ring width is strongly correlated with variables representing soil moisture conditions obtained from the model. Specifically we considered actual evapotranspiration representing the combined effect of water use demand and moisture availability, deficit as the difference between potential evapotranspiration and actual evapotranspiration, representing the severity of water use shortage, and relative soil moisture as the measure of moisture availability. For certain individual months, such as May and June, and various bi-monthly and seasonal combinations (e.g., May-June, April-July, January to July, and July of previous year to current June), the tree-ring chronologies can explain more than 70% of the variation in the soil moisture variables in regression analysis, indicating very good potential for reconstruction of regional soil moisture conditions in the past.

  20. Two centuries temperature variations over subtropical southeast China inferred from Pinus taiwanensis Hayata tree-ring width

    NASA Astrophysics Data System (ADS)

    Cai, QiuFang; Liu, Yu

    2017-03-01

    High-resolution long-term temperature reconstructions in subtropical southeast China (SSC) are very scarce, yet indispensable for the comprehensive understanding of climate change in China, even in East Asia. We reconstructed the first previous growth-season temperature in the Sanqingshan Mountains (SQS), southeast China since 1806 based on tree-ring width data. The reconstruction accounts for 56.4 % of the total variance in the instrumental record over 1954-2009. Unlike the Northern Hemispheric warming during recent two centuries, the reconstruction captured a slowly cooling trend from 1806 to 1980, followed by a rapid warming afterward. 2003-2009 was the warmest period in the reconstruction. 1970-2000 was colder than the last stage of the Little Ice Age (LIA). Most of the warm and cold periods in this reconstruction could be found in the tree-ring based temperature reconstructions of vicinity area, indicating that the temperature variations in SSC were almost synchronous at least at decadal scale. This regional coherence of temperature variation was further confirmed by the spatial correlation patterns with the CRU TS3.22 grid dataset. A strong positive relationship between the temperature over SQS region and sea surface temperature (SST) over the North Pacific Ocean (NP) has been noted, suggesting that SST variations over NP and the related Pacific Decadal Oscillation significantly influenced the temperature variability over SSC. To better understand the climate variability during the LIA and the regional differences in temperature variations over SQS and northern Hemisphere, long data sets from more diverse areas of southern China are needed.

  1. Europan Heat Flow and Crustal Thickness Estimates from Fold Wavelengths and Impact Ring Graben Widths

    NASA Astrophysics Data System (ADS)

    McKinnon, W. B.

    2000-10-01

    Much evidence points to the existence of an ocean on Europa, but the thickness of the surface ice shell is hotly debated. The discovery of folds on Europa by Prockter and Pappalardo (Science 289, 941, 2000) allows in principle a rigorous determination of local heat flow, given that the logical cause, viscous buckling, has been studied in a terrestrial context for decades. The wavelengths observed imply a folding layer thickness probably ≳ 10 times thinner (with adjustment for how precisely one models the brittle-ductile transition, or BDT), or < ~ 2 km at the Astypalaea site (to the BDT). In compression, and assuming prefractured ice of zero cohesion, this implies ~ 5 MPa of differential stress at the BDT. This requires 10s of deg of nonsynchronous rotation (as noted by Prockter and Pappalardo), but the strain rates are probably low ( ~ 2 x 10-17 s-1 based on theoretical models of shell rotation). The high latitude of Astypalaea implies a lower than average surface temperature, however, so the heat flow implied from the strain rate and BDT above is large, ≳ 125 mW m-2 (and grain-size effects are modest). Well-defined ring graben around Tyre and Callanish have widths between ~ 0.75 and 1.5 km. Assuming the master faults of these graben intersect at the extensional BDT and that the appropriate strain rate is much greater than above, conservative assumptions for the latter yield heat flows of ~ 240 mW m-2 for a 1-km thick ``impact lithosphere." These estimates can be added to those discussed in Pappalardo et al. (JGR 104, 24,105, 1999). The above imply conductive shell thicknesses no greater than ~ 5 km, but the heat flows are so large in this case that they would have to be core derived. Alternatively, the heat flows are supplied by a tidally heated, convecting sublayer, and the total shell thickness is greater.

  2. Bayesian multiproxy temperature reconstruction with black spruce ring widths and stable isotopes from the northern Quebec taiga

    NASA Astrophysics Data System (ADS)

    Gennaretti, Fabio; Huard, David; Naulier, Maud; Savard, Martine; Bégin, Christian; Arseneault, Dominique; Guiot, Joel

    2017-03-01

    Northeastern North America has very few millennium-long, high-resolution climate proxy records. However, very recently, a new tree-ring dataset suitable for temperature reconstructions over the last millennium was developed in the northern Quebec taiga. This dataset is composed of one δ18O and six ring width chronologies. Until now, these chronologies have only been used in independent temperature reconstructions (from δ18O or ring width) showing some differences. Here, we added to the dataset a δ13C chronology and developed a significantly improved millennium-long multiproxy reconstruction (997-2006 CE) accounting for uncertainties with a Bayesian approach that evaluates the likelihood of each proxy model. We also undertook a methodological sensitivity analysis to assess the different responses of each proxy to abrupt forcings such as strong volcanic eruptions. Ring width showed a larger response to single eruptions and a larger cumulative impact of multiple eruptions during active volcanic periods, δ18O showed intermediate responses, and δ13C was mostly insensitive to volcanic eruptions. We conclude that all reconstructions based on a single proxy can be misleading because of the possible reduced or amplified responses to specific forcing agents.

  3. A six hundred-year annual minimum temperature history for the central Tibetan Plateau derived from tree-ring width series

    NASA Astrophysics Data System (ADS)

    He, Minhui; Yang, Bao; Datsenko, Nina M.

    2014-08-01

    The recent unprecedented warming found in different regions has aroused much attention in the past years. How temperature has really changed on the Tibetan Plateau (TP) remains unknown since very limited high-resolution temperature series can be found over this region, where large areas of snow and ice exist. Herein, we develop two Juniperus tibetica Kom. tree-ring width chronologies from different elevations. We found that the two tree-ring series only share high-frequency variability. Correlation, response function and partial correlation analysis indicate that prior year annual (January-December) minimum temperature is most responsible for the higher belt juniper radial growth, while more or less precipitation signal is contained by the tree-ring width chronology at the lower belt and is thus excluded from further analysis. The tree growth-climate model accounted for 40 % of the total variance in actual temperature during the common period 1957-2010. The detected temperature signal is further robustly verified by other results. Consequently, a six century long annual minimum temperature history was firstly recovered for the Yushu region, central TP. Interestingly, the rapid warming trend during the past five decades is identified as a significant cold phase in the context of the past 600 years. The recovered temperature series reflects low-frequency variability consistent with other temperature reconstructions over the whole TP region. Furthermore, the present recovered temperature series is associated with the Asian monsoon strength on decadal to multidecadal scales over the past 600 years.

  4. Modeling regional and climatic variation of wood density and ring width in intensively managed Douglas-fir

    Treesearch

    Cosmin N. Filipescue; Eini C. Lowell; Ross Koppenaal; Al K. Mitchell

    2014-01-01

    Characteristics of annual rings are reliable indicators of growth and wood quality in trees. The main objective of our study was to model the variation in annual ring attributes due to intensive silviculture and inherent regional differences in climate and site across a wide geographic range of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco)....

  5. Solar and Climate Variation Relationships Analyzed from Chile Tree Ring Width Time Series (1587 - 1994 A.D.)

    NASA Astrophysics Data System (ADS)

    Rigozo, Nr; Nordemann, Djr; Faria, Hh; Echer, E.; Vieira, Lea; Prestes, A.

    This work presents a study of the relations between solar and climate variations during the last four centuries by spectral analysis of tree ring index and sunspot number time series. Trees used for this study were Pilgerodendron cupressoides from Glaciar Pio XI, in Chile. The spectral analysis of tree ring index shows that 11, 22 and 80 year periodicities of the solar cycle were present in this tree ring data with 0.95 confidence level. This result suggests a solar modulation of climate variations, as recorded by the tree ring growth. Short-term variations, between 2 - 7 years, are also present in tree ring data. Therefore spectral analysis clearly shows that both, solar and climate factors, are recorded in the tree ring data.

  6. Oxygen Isotopes and Ring Widths in the Tropical Tree Species Polylepis tarapacana as Proxies of Past Precipitation in the Tropical Andes of South America.

    NASA Astrophysics Data System (ADS)

    Ballantyne, A. P.; Baker, P.; Jackson, R.; Leavitt, S.; Evans, M.; Sillman, M.

    2002-12-01

    Dendrochronology is a powerful tool for the reconstruction of paleotemperatures in high latitudes and paleo-precipitation in the tropics. The measurement of ring widths and the analysis of carbon and oxygen isotopes within -cellulose have often been used to capture past climate variability. However, most workers have focused their studies in higher latitudes. Here we present preliminary data obtained from tree cores extracted from the alpine tropical tree species Polylepis tarapacana. This widely distributed Andean tree species exhibits robust annual growth rings. We analyzed ä18O values obtained from -cellulose and derived a ring width index from a tree growing on the slopes of Volcan Sajama. This location is significant as this forest is the highest in the world and because Sajama also has a permanent ice cap that has been previously analyzed for ä18O at annual resolution for about one century and at much lower resolution for about 25,000 years (Thompson et al., 1998). It has previously been shown that ring widths of Polylepis at Sajama are well correlated with precipitation amount (Boninsegna, 2002). Here we show that our 40-year long cellulose isotopic time series is well correlated with the annually resolved ice core isotopic record, regionally-averaged instrumental records of precipitation, and the lake-level record of Lake Titicaca (located about 200 km to the north). The amplitude of variability for oxygen isotopes in precipitation and in cellulose is similar; the cellulose ä18O averages about 44 per mil higher than that of the ice or precipitation. Most importantly, ä18O of cellulose and precipitation amount are inversely correlated- more depleted ä18O values in tree cellulose (and in the ice cores) occur in wetter years. These results are promising for the future use of tropical tree cores as past climate proxies of precipitation; such studies are underway in our laboratory.

  7. Did the late spring frost in 2007 and 2011 affect tree-ring width and earlywood vessel size in Pedunculate oak (Quercus robur) in northern Poland?

    PubMed

    Puchałka, Radosław; Koprowski, Marcin; Przybylak, Julia; Przybylak, Rajmund; Dąbrowski, Henryk P

    2016-08-01

    Trees are sensitive to extreme weather and environmental conditions. This sensitivity is visible in tree-ring widths and cell structure. In our study, we hypothesized that the sudden frost noted at the beginning of May in both 2007 and 2011 affected cambial activity and, consequently, the number and size of vessels in the tree rings. It was decided to test this hypothesis after damage to leaves was observed. The applied response function model did not show any significant relationships between spring temperature and growth. However, this method uses average values for long periods and sometimes misses the short-term effects. This is why we decided to study each ring separately, comparing them with rings unaffected by the late frost. Our study showed that the short-term effect of sudden frost in late spring did not affect tree rings and selected cell parameters. The most likely reasons for this are (i) cambial activity producing the earlywood vessels before the occurrence of the observed leaf damage, (ii) the forest micro-climate protecting the trees from the harsh frost and (iii) the temperature decline being too short-lived an event to affect the oaks. On the other hand, the visible damage may be occasional and not affect cambium activity and tree vitality at all. We conclude that oak is well-adapted to this phenomenon.

  8. Did the late spring frost in 2007 and 2011 affect tree-ring width and earlywood vessel size in Pedunculate oak ( Quercus robur) in northern Poland?

    NASA Astrophysics Data System (ADS)

    Puchałka, Radosław; Koprowski, Marcin; Przybylak, Julia; Przybylak, Rajmund; Dąbrowski, Henryk P.

    2016-08-01

    Trees are sensitive to extreme weather and environmental conditions. This sensitivity is visible in tree-ring widths and cell structure. In our study, we hypothesized that the sudden frost noted at the beginning of May in both 2007 and 2011 affected cambial activity and, consequently, the number and size of vessels in the tree rings. It was decided to test this hypothesis after damage to leaves was observed. The applied response function model did not show any significant relationships between spring temperature and growth. However, this method uses average values for long periods and sometimes misses the short-term effects. This is why we decided to study each ring separately, comparing them with rings unaffected by the late frost. Our study showed that the short-term effect of sudden frost in late spring did not affect tree rings and selected cell parameters. The most likely reasons for this are (i) cambial activity producing the earlywood vessels before the occurrence of the observed leaf damage, (ii) the forest micro-climate protecting the trees from the harsh frost and (iii) the temperature decline being too short-lived an event to affect the oaks. On the other hand, the visible damage may be occasional and not affect cambium activity and tree vitality at all. We conclude that oak is well-adapted to this phenomenon.

  9. Occurrence of annual growth rings in Rhizophora mangle in a region with low climate seasonality.

    PubMed

    Souza, Brunna T; Estrada, Gustavo C D; Soares, Mário L G; Callado, Cátia H

    2016-01-01

    The formation of annual growth rings has been confirmed for several mangrove species in the last decade, among which is the Rhizophora mangle. However, the record of annual rings for this species was made in a region with high hydric seasonality, a widely recognized induction factor of annual rings in tropical species. In this sense, the present study aimed to verify the occurrence of annual growth rings in R. mangle in the mangroves of Guaratiba (Rio de Janeiro, Southeastern Brazil), a region with low hydric seasonality. For this purpose, the crossdating technique was applied in ten trees collected with known age (seven years). The growth rings are characterized by alternating layers of low vessel density (earlywood) and high vessel density (latewood). Multiple regression analysis indicated that growth rings width variation is driven by precipitation, water surplus, water deficit and water storage. Crossdating analysis confirmed the existence of annual growth rings in the R. mangle in Guaratiba. This discovery in a region with low hydric seasonality increases the dendrocronological potential of this species and suggests the importance of biological factors (eg. phenological behavior) as complementary inductors for the formation of growth rings in this species.

  10. Interpretation of tree-ring data with a model for primary production, carbon allocation and growth

    NASA Astrophysics Data System (ADS)

    Li, G.; Wang, H.; Harrison, S. P.; Prentice, I. C.

    2013-12-01

    We present a simple, generic model of annual tree growth, called ';T'. This model accepts input from a generic light-use efficiency model which is known to provide good simulations of terrestrial carbon exchange. The light-use efficiency model provides values for Gross Primary Production (GPP) per unit of absorbed photosynthetically active radiation (PAR). Absorbed PAR is estimated from the current leaf area. GPP is allocated to foliage, transport-tissue, and fine-root production and respiration, in such a way as to satisfy well-understood dimensional relationships. The result is a model that can represent both ontogenetic effects and the effects of environmental variations and trends on growth. The model has been applied to simulate ring-width series from multiple individual trees in temperature- and drought-limited contexts. Each tree is initialized at its actual diameter at the time when local climate records started. These records are used to drive the trees' subsequent growth. Realistic simulations of the pattern of interannual variability of ring-width are generated, and shown to relate statistically to climate. An upward trend in ring-width during 1958-2007 is shown to be present in the primary observations, and in the simulations; but not in the standard, detrended ring-width series. This approach combines two modelling approaches previously developed in the global carbon cycle and forest science literature respectively. Neither has been widely applied in the context of tree-ring based climate reconstruction. This combination of methods offers promise, however, because it could provide a way to sidestep several known problems. These include: reliance on correlations for the interpretation of ring-width variations in terms of climate; the necessity of detrending using empirical functions (which can remove trends caused by variations in the environment as well as those that are ontogenetic); and the difficulty of assessing effects of extrinsic, non

  11. Multi-proxy approaches to isolating low-frequency climate signals from tree-ring δ13C, δ18O and ring-widths

    NASA Astrophysics Data System (ADS)

    Voelker, S. L.; Johnstone, J. A.; Roden, J. S.; Dawson, T. E.

    2013-12-01

    Tree-ring stable isotope records have been increasingly used as climate proxies and have often improved the coherence of climate signals compared to ring-width variability. Here we explore the potential for combining tree ring 13C, 18O and ring-width data to isolate low-frequency climate variation from 1) bur oak trees from mid-continental USA and 2) coastal California redwood trees. For modern mid-continental oaks, Δ13C [carbon isotope discrimination] and Δ18O [isotopic enrichment above source water] are negatively correlated across space and time, conditions representative of the bioclimatic envelope for this species. Correlations with the vapor pressure deficit at the growing season maximum temperature (VPDmax) were greatest for the dual isotopic signal as compared to Δ13C or Δ18O alone (r = 0.79, 0.69 and 0.75, respectively). As applied to 59 sub-fossil oak logs [14C-dated to 9.97-13.64k Cal yrs BP] from Missouri, USA, this dual isotope signal indicates that the Pleistocene-Holocene transition was characterized by an abrupt transition near the end of the Younger-Dryas period from a cold, wet and relatively stable growing season climate to a more variable early Holocene climate characterized by periods of greater growing season VPD and maximum temperatures. Our data further suggest that correlations between Δ13C or Δ18O and ring-width chronologies may provide a record of decadal to multi-decadal variability in VPDmax. For coastal California redwoods, from 1951-2003, we demonstrate drastic differences in both sign and magnitude of 11-year running correlations between northern California regional Δ13C or δ18O chronologies for 'middlewood' or 'latewood' (MW or LW) and a regional ring-width chronology. Comparisons of trends in these correlations to 11-year means of Pacific Decadal Oscillation index (PDO, May-September) show similarities with MW or LW Δ13C (r = 0.70 and 0.53, respectively) and stronger correspondence with inverted MW and LW δ18O (r = 0

  12. Using Novel Approaches in Process-Based Modeling for Interpreting Inter-Annual Variability in Tree Ring Widths, Wood Density Profiles, and Cellulose Isotopic Ratios

    NASA Astrophysics Data System (ADS)

    Friend, A. D.; Babst, F.; Belmecheri, S.; Frank, D. C.; Hacket Pain, A. J.; Hayat, A.; Poulter, B.; Rademacher, T. T.; Trouet, V.

    2015-12-01

    Time series annual of tree ring width, density variation, and oxygen and carbon isotopic compositions have the potential to substantially increase our knowledge of forest responses to environmental variation. However, their interpretation is not straightforward due to the simultaneous influences of a number of confounding factors, including carry-over effects from previous years, variable resource allocation with size, age, and canopy position, species-specific physiologies, and complex interactions between forcings such as temperature, soil moisture, and atmospheric CO2. Here we attempt to tease these factors apart and so substantially improve the interpretability of tree ring archives through the construction and application of novel approaches within a process-based model of individual tree growth. The model incorporates descriptions of xylem cell division, expansion, and secondary wall thickening, apical and lateral meristem activities with internal controls from internal signals, internal carbon storage, and the dynamics of canopy photosynthesis, stomatal movements, evapotranspiration, canopy temperatures, and soil moisture. Alternative treatments of isotopic fractionation and growth controls are evaluated using measured datasets. We demonstrate how this new model approach can be used to assess the information contained in tree rings concerning the influence of increasing atmospheric CO2 over the past century on growth and water use efficiency at a range of sites.

  13. Spring temperatures in the far-western Nepal Himalaya since AD 1640 reconstructed from Picea smithiana tree-ring widths

    NASA Astrophysics Data System (ADS)

    Thapa, Udya Kuwar; Shah, Santosh K.; Gaire, Narayan Prasad; Bhuju, Dinesh Raj

    2015-10-01

    We developed a new, 422-year long tree-ring width chronology (spanning AD 1591-2012) from Picea smithiana (Wall.) Boiss in Khaptad National Park, which is located in the far-western Nepalese Himalaya. Seasonal correlation analysis revealed significant indirect relationship with spring temperature and lead to the reconstruction of March-May average temperature for the past 373 years (AD 1640-2012). The reconstruction was found significant based on validation statistics commonly used in tree-ring based climate reconstruction. Furthermore, it was validated through spatial correlation with gridded temperature data. This temperature reconstruction identified several periods of warming and cooling. The reconstruction did not show the significant pattern of cooling during the Little Ice Age but there were few cold episodes recorded. The spring temperature revealed relationship with different Sea Surface Temperature index over the equatorial Pacific Ocean, which showed linkages with climatic variability in a global scale.

  14. Narrow line-width single-longitudinal-mode fiber laser using silicon-on-insulator based micro-ring-resonator

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Hsu, Yung; Hsu, Chin-Wei; Yang, Ling-Gang; Chow, Chi-Wai; Yeh, Chien-Hung; Lai, Yin-Chieh; Tsang, Hon-Ki

    2016-02-01

    In this work, we propose and demonstrate a stable single-longitudinal-mode (SLM) fiber laser with narrow line-width by using an integrated silicon-on-insulator micro-ring resonator (SOI MRR) and two subsidiary fiber rings for the first time, to the best of our knowledge. The laser is tunable over the wavelength range from 1546 to 1570 nm, with only step tuning of 2 nm steps. A maximum 49 dB side mode suppression ratio (SMSR) can be achieved. The compact SOI MRR provides a large free-spectral-range (FSR), while the subsidiary rings provide Vernier effect producing a single lasing mode. The FSR of the SOI MRR can be very large and controllable (since it is easy to fabricate small SOI MRR when compared with making small fiber-rings) using the complementary-metal-oxide-semiconductor (CMOS) compactable SOI fabrication processes. In our proposed laser, the measured single sideband (SSB) spectrum shows that the densely spaced longitudinal modes can be significantly suppressed to achieve SLM. The laser linewidth is only 3.5 kHz measured by using the self-heterodyne method. 30 min stability evaluation in terms of lasing wavelength and optical power is performed; showing the optical wavelength and power are both very stable, with fluctuations of only 0.02 nm and 0.8 dB, respectively.

  15. Tree-ring-width-based PDSI reconstruction for central Inner Mongolia, China over the past 333 years

    NASA Astrophysics Data System (ADS)

    Liu, Yu; Zhang, Xinjia; Song, Huiming; Cai, Qiufang; Li, Qiang; Zhao, Boyang; Liu, Han; Mei, Ruochen

    2017-02-01

    A tree-ring-width chronology was developed from Pinus tabulaeformis aged up to 333 years from central Inner Mongolia, China. The chronology was significantly correlated with the local Palmer Drought Severity Index (PDSI). We therefore reconstructed the first PDSI reconstruction from March to June based on the local tree ring data from 1680 to 2012 AD. The reconstruction explained 40.7 % of the variance (39.7 % after adjusted the degrees of freedom) of the actual PDSI during the calibration period (1951-2012 AD). The reconstructed PDSI series captured the severe drought event of the late 1920s, which occurred extensively in northern China. Running variance analyses indicated that the variability of drought increased sharply after 1960, indicating more drought years, which may imply anthropogenic related global warming effects in the region. In the entire reconstruction, there were five dry periods: 1730-1814 AD, 1849-1869 AD, 1886-1942 AD (including severe drought in late 1920s), 1963-1978 AD and 2004-2007 AD; and five wet periods: 1685-1729 AD, 1815-1848 AD, 1870-1885 AD, 1943-1962 AD and 1979-2003 AD. Conditions turned dry after 2003 AD, and the PDSI from March to June (PDSI36) captured many interannual extreme drought events since then, such as 2005-2008 AD. The reconstruction is comparable to other tree-ring-width-based PDSI series from the neighboring regions, indicating that our reconstruction has good regional representativeness. Significant relationships were found between our PDSI reconstruction and the solar radiation cycle and the sun spot cycle, North Atlantic Oscillation, the El Niño-Southern Oscillation, as well as the Pacific Decadal Oscillation. Power spectral analyses detected 147.0-, 128.2-, 46.5-, 6.5-, 6.3-, 2.6-, 2.2- and 2.0-year quasi-cycles in the reconstructed series.

  16. Extension of Miles Equation for Ring Baffle Damping Predictions to Small Slosh Amplitudes and Large Baffle Widths

    NASA Technical Reports Server (NTRS)

    West, Jeff; Yang, H. Q.; Brodnick, Jacob; Sansone, Marco; Westra, Douglas

    2016-01-01

    The Miles equation has long been used to predict slosh damping in liquid propellant tanks due to ring baffles. The original work by Miles identifies defined limits to its range of application. Recent evaluations of the Space Launch System identified that the Core Stage baffle designs resulted in violating the limits of the application of the Miles equation. This paper describes the work conducted by NASA/MSFC to develop methods to predict slosh damping from ring baffles for conditions for which Miles equation is not applicable. For asymptotically small slosh amplitudes or conversely large baffle widths, an asymptotic expression for slosh damping was developed and calibrated using historical experimental sub-scale slosh damping data. For the parameter space that lies between region of applicability of the asymptotic expression and the Miles equation, Computational Fluid Dynamics simulations of slosh damping were used to develop an expression for slosh damping. The combined multi-regime slosh prediction methodology is shown to be smooth at regime boundaries and consistent with both sub-scale experimental slosh damping data and the results of validated Computational Fluid Dynamics predictions of slosh damping due to ring baffles.

  17. Spatiotemporal patterns of ring-width variability in the northern interior west

    Treesearch

    R. Justin DeRose; John D. Shaw; James N. Long

    2015-01-01

    A fundamental goal of forest biogeography is to understand the factors that drive spatiotemporal variability in forest growth across large areas (e.g., states or regions). The ancillary collection of increment cores as part of the IW FIA Program represents an important non-traditional role for the development of unprecedented data sets. Individual-tree growth data from...

  18. A study of emittance growth in the recycler ring

    SciTech Connect

    Krishnaswamy Gounder et al.

    2001-07-20

    We investigate processes contributing to emittance growth in the Fermilab Recycler Ring. In addition to beam-gas multiple scattering, we also examine other external factors such as Main Injector ramping affecting the emittance growth.

  19. Direct measurement of the plasma loss width in an optimized, high ionization fraction, magnetic multi-dipole ring cusp

    NASA Astrophysics Data System (ADS)

    Cooper, C. M.; Weisberg, D. B.; Khalzov, I.; Milhone, J.; Flanagan, K.; Peterson, E.; Wahl, C.; Forest, C. B.

    2016-10-01

    The loss width of plasma in the WiPAL multi-dipole magnetic ring cusp [Cooper et al., Phys. Plasmas 21, 13505 (2014); Forest et al., J. Plasma Phys. 81, 345810501 (2015)] has been directly measured using a novel array of probes embedded in the insulating plasma limiters. The large plasma volume ( ˜10 m3), small loss area associated with strong rare earth permanent magnets ( Bo˜2.23 kG at face), and large heating power ( ≤200 kW) produces a broad range of electron temperatures ( 2 width is much larger than the Debye length and electron gyroradius and comparable to the collision length. Plasma parameters measured at the surface of ceramic limiter tiles covering the magnets and along radial chords in the cusp magnetic field indicate that electron density and temperature are nearly constant on magnetic field lines and that the mirror forces play little role in confining the plasma other than to constrict the loss area. Particle balance modeling is used to determine the cross field diffusion coefficient base on the measured losses to the limiters. The experimentally determined cross field diffusion coefficient (which determines the cusp loss width) is consistent with ambipolar diffusion across five orders of magnitude. The ambipolar diffusion across a given field line is set primarily by the electron-neutral collisions in the region where the magnetic field is the weakest, even though these plasmas can have ionization fractions near 1.

  20. Reconstructed summer temperatures over the last 400 years based on larch ring widths: Sakhalin Island, Russian Far East

    NASA Astrophysics Data System (ADS)

    Wiles, Gregory C.; Solomina, Olga; D'Arrigo, Rosanne; Anchukaitis, Kevin J.; Gensiarovsky, Yury V.; Wiesenberg, Nicholas

    2015-07-01

    A new ring-width record from the eastern flanks of the Eastern Sakhalin Range, Sakhalin Island, Russian Federation is significantly correlated with summer temperatures and allows for the reconstruction of May-July average temperatures for the past 400 years. The reconstruction explains 37 % of the variance in May-July temperatures and shows a strong cooling between 1680 and 1710 CE coincident with the Maunder solar minimum and in agreement with other independent tree-ring reconstructions and glacier histories from sites along the margin of the Sea of Okhotsk. While recent decades are among the warmest in the record they are rivaled by periods centered on 1650 and 1850 CE. Warming in the observational record and the reconstruction is consistent with the influence of the declining strength of the Siberian High and loss of sea ice over the same interval. Decadal (17-25 year) variability persists throughout the reconstruction. At interannual timescales the Sakhalin reconstruction is most strongly correlated with local and central North Pacific sea surface temperatures over the past 120 years, whereas at decadal timescales there is an additional association with Asian land surface temperatures.

  1. Parameterization of tree-ring growth in Siberia

    NASA Astrophysics Data System (ADS)

    Tychkov, Ivan; Popkova, Margarita; Shishov, Vladimir; Vaganov, Eugene

    2016-04-01

    No doubt, climate-tree growth relationship is an one of the useful and interesting subject of studying in dendrochronology. It provides an information of tree growth dependency on climatic environment, but also, gives information about growth conditions and whole tree-ring growth process for long-term periods. New parameterization approach of the Vaganov-Shashkin process-based model (VS-model) is developed to described critical process linking climate variables with tree-ring formation. The approach (co-called VS-Oscilloscope) is presented as a computer software with graphical interface. As most process-based tree-ring models, VS-model's initial purpose is to describe variability of tree-ring radial growth due to variability of climatic factors, but also to determinate principal factors limiting tree-ring growth. The principal factors affecting on the growth rate of cambial cells in the VS-model are temperature, day light and soil moisture. Detailed testing of VS-Oscilloscope was done for semi-arid area of southern Siberia (Khakassian region). Significant correlations between initial tree-ring chronologies and simulated tree-ring growth curves were obtained. Direct natural observations confirm obtained simulation results including unique growth characteristic for semi-arid habitats. New results concerning formation of wide and narrow rings under different climate conditions are considered. By itself the new parameterization approach (VS-oscilloscope) is an useful instrument for better understanding of various processes in tree-ring formation. The work was supported by the Russian Science Foundation (RSF # 14-14-00219).

  2. Effect of tree-ring detrending method on apparent growth trends of black and white spruce in interior Alaska

    NASA Astrophysics Data System (ADS)

    Sullivan, Patrick F.; Pattison, Robert R.; Brownlee, Annalis H.; Cahoon, Sean M. P.; Hollingsworth, Teresa N.

    2016-11-01

    Boreal forests are critical sinks in the global carbon cycle. However, recent studies have revealed increasing frequency and extent of wildfires, decreasing landscape greenness, increasing tree mortality and declining growth of black and white spruce in boreal North America. We measured ring widths from a large set of increment cores collected across a vast area of interior Alaska and examined implications of data processing decisions for apparent trends in black and white spruce growth. We found that choice of detrending method had important implications for apparent long-term growth trends and the strength of climate-growth correlations. Trends varied from strong increases in growth since the Industrial Revolution, when ring widths were detrended using single-curve regional curve standardization (RCS), to strong decreases in growth, when ring widths were normalized by fitting a horizontal line to each ring width series. All methods revealed a pronounced growth peak for black and white spruce centered near 1940. Most detrending methods showed a decline from the peak, leaving recent growth of both species near the long-term mean. Climate-growth analyses revealed negative correlations with growing season temperature and positive correlations with August precipitation for both species. Multiple-curve RCS detrending produced the strongest and/or greatest number of significant climate-growth correlations. Results provide important historical context for recent growth of black and white spruce. Growth of both species might decline with future warming, if not mitigated by increasing precipitation. However, widespread drought-induced mortality is probably not imminent, given that recent growth was near the long-term mean.

  3. Effect of tree-ring detrending method on apparent growth trends of black and white spruce in interior Alaska

    Treesearch

    Patrick F Sullivan; Robert R Pattison; Annalis H Brownlee; Sean M P Cahoon; Teresa N Hollingsworth

    2016-01-01

    Boreal forests are critical sinks in the global carbon cycle. However, recent studies have revealed increasing frequency and extent of wildfires, decreasing landscape greenness, increasing tree mortality and declining growth of black and white spruce in boreal North America. We measured ring widths from a large set of increment cores collected across a vast area of...

  4. A diffusive model for halo width growth during vertical displacement events

    NASA Astrophysics Data System (ADS)

    Eidietis, N. W.; Humphreys, D. A.

    2011-07-01

    The electromagnetic loads produced by halo currents during vertical displacement events (VDEs) impose stringent requirements on the strength of ITER in-vessel components. A predictive understanding of halo current evolution is essential for ensuring the robust design of these components. A significant factor determining that evolution is the plasma resistance, which is a function of three quantities: the resistivities of the core and halo regions, and the halo region width. A diffusive model of halo width growth during VDEs has been developed, which provides one part of a physics basis for predictive halo current simulations. The diffusive model was motivated by DIII-D observations that VDEs with cold post-thermal quench plasma and a current decay time much faster than the vertical motion (type I VDE) possess much wider halo region widths than warmer plasma VDEs, where the current decay is much slower than the vertical motion (type II). A 2D finite element code is used to model the diffusion of toroidal halo current during selected type I and type II DIII-D VDEs. The model assumes a core plasma region within the last closed flux surface (LCFS) diffusing current into a halo plasma filling the vessel outside the LCFS. LCFS motion and plasma temperature are prescribed from experimental observations. The halo width evolution produced by this model compares favourably with experimental measurements of type I and type II toroidal halo current width evolution.

  5. Formula for growth rate of mixing width applied to Richtmyer-Meshkov instability

    NASA Astrophysics Data System (ADS)

    Gao, Fujie; Zhang, Yousheng; He, Zhiwei; Tian, Baolin

    2016-11-01

    The mixing zone width and its growth rate are of great significance in the study of the Richtmyer-Meshkov instability (RMI). In this paper, a formula for the growth rate of the mixing width is proposed for analysis of the RMI-induced mixing process. A new definition of the mixing width h ˙ , based on the mass fraction ϕ, is used to derive the formula of the growth rate of the mixing width, h ˙ . In the derivation, the velocity field and the diffusion term are concisely introduced into the formula by using the mass equation and mass fraction equation. This formula is used together with two-dimensional (2D) and three-dimensional (3D) numerical data to quantitatively study the effects of compressibility and the diffusion process on the development of the RMI. The results based on our simulations show the following. After a shock, the magnitudes of the contributions of compressibility and diffusion to h ˙ increase initially, and in the middle stage of the RMI, they appear to attain a maximum value, around 10%; however, under some conditions (e.g., absolute value of Atwood number ˜0.9), this value can be more than 10%. The results indicate that compressibility and the diffusion process become important in the later stages of the RMI and the neglect of these physical processes is not always suitable. This study shows that the derived formula is not only an approach for modeling of the mixing zone width but also a quantitative tool for the study of an RMI-induced mixing process. This formula is expected to be useful in the analysis of turbulent mixing in the later stages of the RMI process.

  6. Sensitivity of ring growth and carbon allocation to climatic variation vary within ponderosa pine trees.

    PubMed

    Kerhoulas, Lucy P; Kane, Jeffrey M

    2012-01-01

    Most dendrochronological studies focus on cores sampled from standard positions (main stem, breast height), yet vertical gradients in hydraulic constraints and priorities for carbon allocation may contribute to different growth sensitivities with position. Using cores taken from five positions (coarse roots, breast height, base of live crown, mid-crown branch and treetop), we investigated how radial growth sensitivity to climate over the period of 1895-2008 varies by position within 36 large ponderosa pines (Pinus ponderosa Dougl.) in northern Arizona. The climate parameters investigated were Palmer Drought Severity Index, water year and monsoon precipitation, maximum annual temperature, minimum annual temperature and average annual temperature. For each study tree, we generated Pearson correlation coefficients between ring width indices from each position and six climate parameters. We also investigated whether the number of missing rings differed among positions and bole heights. We found that tree density did not significantly influence climatic sensitivity to any of the climate parameters investigated at any of the sample positions. Results from three types of analyses suggest that climatic sensitivity of tree growth varied with position height: (i) correlations of radial growth and climate variables consistently increased with height; (ii) model strength based on Akaike's information criterion increased with height, where treetop growth consistently had the highest sensitivity and coarse roots the lowest sensitivity to each climatic parameter; and (iii) the correlation between bole ring width indices decreased with distance between positions. We speculate that increased sensitivity to climate at higher positions is related to hydraulic limitation because higher positions experience greater xylem tensions due to gravitational effects that render these positions more sensitive to climatic stresses. The low sensitivity of root growth to all climatic variables

  7. Detecting long-term growth trends using tree rings: a critical evaluation of methods.

    PubMed

    Peters, Richard L; Groenendijk, Peter; Vlam, Mart; Zuidema, Pieter A

    2015-05-01

    Tree-ring analysis is often used to assess long-term trends in tree growth. A variety of growth-trend detection methods (GDMs) exist to disentangle age/size trends in growth from long-term growth changes. However, these detrending methods strongly differ in approach, with possible implications for their output. Here, we critically evaluate the consistency, sensitivity, reliability and accuracy of four most widely used GDMs: conservative detrending (CD) applies mathematical functions to correct for decreasing ring widths with age; basal area correction (BAC) transforms diameter into basal area growth; regional curve standardization (RCS) detrends individual tree-ring series using average age/size trends; and size class isolation (SCI) calculates growth trends within separate size classes. First, we evaluated whether these GDMs produce consistent results applied to an empirical tree-ring data set of Melia azedarach, a tropical tree species from Thailand. Three GDMs yielded similar results - a growth decline over time - but the widely used CD method did not detect any change. Second, we assessed the sensitivity (probability of correct growth-trend detection), reliability (100% minus probability of detecting false trends) and accuracy (whether the strength of imposed trends is correctly detected) of these GDMs, by applying them to simulated growth trajectories with different imposed trends: no trend, strong trends (-6% and +6% change per decade) and weak trends (-2%, +2%). All methods except CD, showed high sensitivity, reliability and accuracy to detect strong imposed trends. However, these were considerably lower in the weak or no-trend scenarios. BAC showed good sensitivity and accuracy, but low reliability, indicating uncertainty of trend detection using this method. Our study reveals that the choice of GDM influences results of growth-trend studies. We recommend applying multiple methods when analysing trends and encourage performing sensitivity and reliability

  8. A Standardized Precipitation Evapotranspiration Index Reconstruction in the Taihe Mountains Using Tree-Ring Widths for the Last 283 Years.

    PubMed

    Ma, Yongyong; Liu, Yu; Song, Huiming; Sun, Junyan; Lei, Ying; Wang, Yanchao

    2015-01-01

    Tree-ring samples from Chinese Pine (Pinus tabulaeformis Carr.) that were collected in the Taihe Mountains on the western Loess Plateau, China, were used to analyze the effects of climate and drought on radial growth and to reconstruct the mean April-June Standardized Precipitation Evapotranspiration Index (SPEI) during the period 1730-2012 AD. Precipitation positively affected tree growth primarily during wet seasons, while temperature negatively affected tree growth during dry seasons. Tree growth responded positively to SPEI at long time scales most likely because the trees were able to withstand water deficits but lacked a rapid response to drought. The 10-month scale SPEI was chosen for further drought reconstruction. A calibration model for the period 1951-2011 explained 51% of the variance in the modeled SPEI data. Our SPEI reconstruction revealed long-term patterns of drought variability and captured some significant drought events, including the severe drought of 1928-1930 and the clear drying trend since the 1950s which were widespread across northern China. The reconstruction was also consistent with two other reconstructions on the western Loess Plateau at both interannual and decadal scales. The reconstructed SPEI series showed synchronous variations with the drought/wetness indices and spatial correlation analyses indicated that this reconstruction could be representative of large-scale SPEI variability in northern China. Period analysis discovered 128-year, 25-year, 2.62-year, 2.36-year, and 2.04-year cycles in this reconstruction. The time-dependency of the growth response to drought should be considered in further studies of the community dynamics. The SPEI reconstruction improves the sparse network of long-term climate records for an enhanced understanding of climatic variability on the western Loess Plateau, China.

  9. A Standardized Precipitation Evapotranspiration Index Reconstruction in the Taihe Mountains Using Tree-Ring Widths for the Last 283 Years

    PubMed Central

    Ma, Yongyong; Liu, Yu; Song, Huiming; Sun, Junyan; Lei, Ying; Wang, Yanchao

    2015-01-01

    Tree-ring samples from Chinese Pine (Pinus tabulaeformis Carr.) that were collected in the Taihe Mountains on the western Loess Plateau, China, were used to analyze the effects of climate and drought on radial growth and to reconstruct the mean April-June Standardized Precipitation Evapotranspiration Index (SPEI) during the period 1730–2012 AD. Precipitation positively affected tree growth primarily during wet seasons, while temperature negatively affected tree growth during dry seasons. Tree growth responded positively to SPEI at long time scales most likely because the trees were able to withstand water deficits but lacked a rapid response to drought. The 10-month scale SPEI was chosen for further drought reconstruction. A calibration model for the period 1951–2011 explained 51% of the variance in the modeled SPEI data. Our SPEI reconstruction revealed long-term patterns of drought variability and captured some significant drought events, including the severe drought of 1928–1930 and the clear drying trend since the 1950s which were widespread across northern China. The reconstruction was also consistent with two other reconstructions on the western Loess Plateau at both interannual and decadal scales. The reconstructed SPEI series showed synchronous variations with the drought/wetness indices and spatial correlation analyses indicated that this reconstruction could be representative of large-scale SPEI variability in northern China. Period analysis discovered 128-year, 25-year, 2.62-year, 2.36-year, and 2.04-year cycles in this reconstruction. The time-dependency of the growth response to drought should be considered in further studies of the community dynamics. The SPEI reconstruction improves the sparse network of long-term climate records for an enhanced understanding of climatic variability on the western Loess Plateau, China. PMID:26207621

  10. A 323-year long reconstruction of drought for SW Romania based on black pine ( Pinus Nigra) tree-ring widths

    NASA Astrophysics Data System (ADS)

    Levanič, Tom; Popa, Ionel; Poljanšek, Simon; Nechita, Constantin

    2013-09-01

    Increase in temperature and decrease in precipitation pose a major future challenge for sustainable ecosystem management in Romania. To understand ecosystem response and the wider social consequences of environmental change, we constructed a 396-year long (1615-2010) drought sensitive tree-ring width chronology (TRW) of Pinus nigra var. banatica (Georg. et Ion.) growing on steep slopes and shallow organic soil. We established a statistical relationship between TRW and two meteorological parameters—monthly sum of precipitation (PP) and standardised precipitation index (SPI). PP and SPI correlate significantly with TRW ( r = 0.54 and 0.58) and are stable in time. Rigorous statistical tests, which measure the accuracy and prediction ability of the model, were all significant. SPI was eventually reconstructed back to 1688, with extreme dry and wet years identified using the percentile method. By means of reconstruction, we identified two so far unknown extremely dry years in Romania—1725 and 1782. Those 2 years are almost as dry as 1946, which was known as the "year of great famine." Since no historical documents for these 2 years were available in local archives, we compared the results with those from neighbouring countries and discovered that both years were extremely dry in the wider region (Slovakia, Hungary, Anatolia, Syria, and Turkey). While the 1800-1900 period was relatively mild, with only two moderately extreme years as far as weather is concerned, the 1900-2009 period was highly salient owing to the very high number of wet and dry extremes—five extremely wet and three extremely dry events (one of them in 1946) were identified.

  11. Ring-widths of the above tree-line shrub Rhododendron reveal the change of minimum winter temperature over the past 211 years in Southwestern China

    NASA Astrophysics Data System (ADS)

    Bi, Yingfeng; Xu, Jianchu; Yang, Jinchao; Li, Zongshan; Gebrekirstos, Aster; Liang, Eryuan; Zhang, Shibao; Yang, Yang; Yang, Yongping; Yang, Xuefei

    2016-08-01

    Changes in minimum winter temperature (MWT) and their potential effects on plant growth and development have been gaining increased scientific attention. To better understand these changes across long temporal scales, the present study used dendroclimatological techniques to assess variations in MWT in Southwestern China. Using data from Rhododendron species distributed in areas above the tree-line, a regional composite chronology was generated for a 341-year period. Based on the significant negative correlation between MWT values and ring-width, the most reliable parts of this chronological data were then used to reconstruct MWT values for the past 211 years. This reconstructed MWT series showed decadal to multi-decadal fluctuations. Three distinct cold periods prevailed during 1823-1858, 1882-1891 and 1922-1965, while four warm intervals occurred in 1800-1822, 1858-1881, 1892-1921 and 1966-2011. Our reconstructed MWT reveals a warming trend over the most recent eight decades, which is in agreement with instrumental observations. However, the MWT values and rate of warming over the past seven decades did not exceed those found in the reconstructed temperature data for the past 211 years. Spatial correlations reveal that the MWT in Southwest China is strongly associated with regional temperatures in the Eastern and Central Himalaya, Northern China, and the Indian Peninsula. Larger scale climate oscillations of the Western Pacific and Northern Indian Ocean as well as the North Atlantic Oscillation probably influenced the region's temperature in the past.

  12. Ring-widths of the above tree-line shrub Rhododendron reveal the change of minimum winter temperature over the past 211 years in Southwestern China

    NASA Astrophysics Data System (ADS)

    Bi, Yingfeng; Xu, Jianchu; Yang, Jinchao; Li, Zongshan; Gebrekirstos, Aster; Liang, Eryuan; Zhang, Shibao; Yang, Yang; Yang, Yongping; Yang, Xuefei

    2017-06-01

    Changes in minimum winter temperature (MWT) and their potential effects on plant growth and development have been gaining increased scientific attention. To better understand these changes across long temporal scales, the present study used dendroclimatological techniques to assess variations in MWT in Southwestern China. Using data from Rhododendron species distributed in areas above the tree-line, a regional composite chronology was generated for a 341-year period. Based on the significant negative correlation between MWT values and ring-width, the most reliable parts of this chronological data were then used to reconstruct MWT values for the past 211 years. This reconstructed MWT series showed decadal to multi-decadal fluctuations. Three distinct cold periods prevailed during 1823-1858, 1882-1891 and 1922-1965, while four warm intervals occurred in 1800-1822, 1858-1881, 1892-1921 and 1966-2011. Our reconstructed MWT reveals a warming trend over the most recent eight decades, which is in agreement with instrumental observations. However, the MWT values and rate of warming over the past seven decades did not exceed those found in the reconstructed temperature data for the past 211 years. Spatial correlations reveal that the MWT in Southwest China is strongly associated with regional temperatures in the Eastern and Central Himalaya, Northern China, and the Indian Peninsula. Larger scale climate oscillations of the Western Pacific and Northern Indian Ocean as well as the North Atlantic Oscillation probably influenced the region's temperature in the past.

  13. Counting Tree Growth Rings Moderately Difficult to Distinguish

    Treesearch

    C. B. Briscoe; M. Chudnoff

    1964-01-01

    There is an extensive literature dealing with techniques and gadgets to facilitate counting tree growth rings. A relatively simple method is described below, satisfactory for species too difficult to count in the field, but not sufficiently difficult to require the preparation of microscope slides nor staining techniques.

  14. [Tree-ring growth responses of Mongolian oak (Quercus mongolica) to climate change in southern northeast: a case study in Qianshan Mountains].

    PubMed

    Teng, Li; Xing-Yuan, He; Zhen-Ju, Chen

    2014-07-01

    Mongolian oak is one of the most important broad-leaved tree species in forests, Northeast China. Based on the methodology of dendrochronology, the variations of tree ring radial growth of Mongolian oak in Qianshan Mountains, south of Northeast China, were analyzed. Combined with the temperature and precipitation data from meteorological stations since 1951, the relationships between standardized tree ring width chronology and main climatic factors were analyzed. In this region, the precipitation between April and July of the current year had an significant relationship with the tree ring width of Mongolian oak, and was the main factor limiting the radial growth. The extreme maximum temperature of May was also a key factor influencing the tree ring width, which had a significant on the tree ring width of Mongolian oak. The precipitation in April had a significant and stable relationship with the growth of Mongolian oak since the 1950s. The 'divergence problem' was found in the study area, which the sensitivity of tree growth to summer temperature reduced since the 1980s. The tree growth response to temperature showed a seasonal change from summer to spring.

  15. Mechanical Stress-Induced Sarcomere Assembly for Cardiac Muscle Growth in Length and Width

    PubMed Central

    Russell, Brenda; Curtis, Matthew W.; Koshman, Yevgeniya E.; Samarel, Allen M.

    2010-01-01

    A ventricular myocyte experiences changes in length and load during every beat of the heart and has the ability to remodel cell shape to maintain cardiac performance. Specifically, myocytes elongate in response to increased diastolic strain by adding sarcomeres in series, and they thicken in response to continued systolic stress by adding filaments in parallel. Myocytes do this while still keeping the resting sarcomere length close to its optimal value at the peak of the length-tension curve. This review focuses on the little understood mechanisms by which direction of growth is matched in a physiologically appropriate direction. We propose that the direction of strain is detected by differential phosphorylation of proteins in the costamere, which then transmit signaling to the Z-disc for parallel or series addition of thin filaments regulated via the actin-capping processes. In this review, we link mechanotransduction to the molecular mechanisms for regulation of myocyte length and width. PMID:20188736

  16. Tropical tree rings reveal preferential survival of fast-growing juveniles and increased juvenile growth rates over time.

    PubMed

    Rozendaal, Danaë M A; Brienen, Roel J W; Soliz-Gamboa, Claudia C; Zuidema, Pieter A

    2010-02-01

    Long-term juvenile growth patterns of tropical trees were studied to test two hypotheses: fast-growing juvenile trees have a higher chance of reaching the canopy ('juvenile selection effect'); and tree growth has increased over time ('historical growth increase'). Tree-ring analysis was applied to test these hypotheses for five tree species from three moist forest sites in Bolivia, using samples from 459 individuals. Basal area increment was calculated from ring widths, for trees < 30 cm in diameter. For three out of five species, a juvenile selection effect was found in rings formed by small juveniles. Thus, extant adult trees in these species have had higher juvenile growth rates than extant juvenile trees. By contrast, rings formed by somewhat larger juveniles in four species showed the opposite pattern: a historical growth increase. For most size classes of > 10 cm diameter none of the patterns was found. Fast juvenile growth may be essential to enable tropical trees to reach the forest canopy, especially for small juvenile trees in the dark forest understorey. The historical growth increase requires cautious interpretation, but may be partially attributable to CO(2) fertilization.

  17. Tree-ring latewood width based July-August SPEI reconstruction in South China since AD 1888 and its possible connection with ENSO

    NASA Astrophysics Data System (ADS)

    Zhao, Yesi; Shi, Jiangfeng; Shi, Shiyuan; Yu, Jian; Lu, Huayu

    2017-04-01

    Our understanding of the long-term hydroclimate variations in South China is prohibited by the shortness of meteorological records. Paleoclimatic proxies, such as tree-rings, can be pursued to extend the meteorological records back for centuries to help us better understand hydroclimatic conditions. In this study, we reconstructed the July-August Standardized Precipitation-Evapotranspiration Index (SPEIJul-Aug) based on a newly developed 127-year adjusted latewood width chronology from Tsuga longibracteata, South China. In specific, the latewood width chronology was regressed on the earlywood width chronology using a simple linear regression, and the residuals plus a constant 1.0 were defined as the adjusted latewood width chronology. The chronology explained 40% of the actual SPEIJul-Aug variance in the period 1953-2014. The reconstructed SPEIJul-Aug can represent large-scale July-August SPEI variations over South China, including northern Guangxi, Hunan, and Guizhou provinces. From the perspective of the past 127 years, the extreme summer drought in 2013 was not unusual because more extreme drought events occurred in the first half of the 20th century. A significant 2.0-3.6-year hydroclimatic cycle existed in the reconstruction, which indicated that the SPEIJul-Aug might be driven by El Niño-Southern Oscillation (ENSO). We further checked the time-dependency of the relationship between SPEIJul-Augand ENSO and found that it was unstable. Their relationship was weak before the 1950s, became significant from the 1950s to early 1990s, and then dropped to be weak again and even out of phase since the early 1990s, which may be attributable to the significant westward extension of the western Pacific subtropical high. This study indicates that summer hydroclimate in South China can be reconstructed based on adjusted latewood width, and will be better understood when more and longer adjusted latewood width chronologies are obtained in the near future.

  18. Summer warming and changes in snow depth is reflected in the growth rings of Alaskan tundra shrubs (Toolik Lake)

    NASA Astrophysics Data System (ADS)

    Buchwal, A.; Welker, J. M.

    2016-12-01

    Arctic change is being manifested by shifts in the vegetation composition and abundance throughout many regions of the Arctic. These changes are primarily reflected by increases in shrub growth and density, but the extent to which shrub growth is expressed in greater shrub ring width and the degree to which natural and experimental warming correspond and or whether the secondary effect of deeper snow in winter acts to alter shrub ring growh and or shrub biomass is yet to be determined for Arctic Alaska. In order to explore growth response of arctic shrubs to on-going and predicted temperature and snow depth increase we investigated shrubs' annual growth rings using dendrochronological methods applied to plants growing under control and experimental treatments in Toolik Lake, Northern Alaska. Specifically we evaluated the effects of a 20-year experimental warming (due to open top chambers, OTC's) and snow depth increases on the growth rings pattern of two common shrub species of Northern Alaska, i.e. Betula nana and Salix pulchra. By applying a serial sectioning method patterns of annual growth were investigated across the entire plant including below-ground parts. Moreover this procedure allowed for a complete cross-dating and a detection of irregular radial growth, including common missing and partially missing rings. We found that the natural warming in Alaska occurring over the past 20 years is stimulating shrub ring growth, more so for Betula than for Salix. Experimental warming (simulating conditions in approximately 2030) stimulated the secondary growth ratio; however the allocation pattern between below-ground and above-ground is quite variable between individual shrubs. In addition, annual growth rings analyses were supplemented by quantitative wood anatomy properties, such as vessel size and density. Our findings indicate that there can be differential growth ring responses of deciduous shrubs to natural climate warming, that growth ring increases reflect

  19. Radial growth of an extended spoke in Saturn's B ring

    NASA Technical Reports Server (NTRS)

    Eplee, R. E., Jr.; Smith, B. A.

    1985-01-01

    An analysis is reported of the pattern of radial growth of an extended spoke observed in the Voyager 2 low-resolution Saturn ring 'movie'. The feature is atypical in that it orbits Saturn at the corotational rate for 1-1/2 hours after the onset of its formation and then undergoes a 40-min acceleration to sustained Keplerian velocities. A correlation between the dynamical phases and the radial growth modes of the spoke is observed, one that seems consistent with the plasma cloud model of spoke formation and evolution proposed by Goertz and Morfill (1983), taken in the limit of high charge density.

  20. Stimulated longitudinal emittance growth in the Main Ring

    SciTech Connect

    Jackson, G.; Ieiri, T.

    1989-03-01

    During fixed target operations -- beam intensity is limited by coherent instabilities in both the Main Ring and Tevatron. The growth rates for instabilities are generally inversely proportional to the proton bunch length. Since fixed target operations are insensitive to the longitudinal emittance of the beams, bunch spreaders are employed to increase the emittance, and hence the bunch length. Emittance growth is stimulated by injecting noise onto either the RF phase or amplitude control voltages. Test results of the efficiency of various stimulation schemes are reported. The design of a bunch length monitor, used to measure the effect of the bunch spreader, is also presented. 12 refs., 5 figs.

  1. Variations in Environmental Signals in Tree-Ring Indices in Trees with Different Growth Potential

    PubMed Central

    Hafner, Polona; Gričar, Jožica; Skudnik, Mitja; Levanič, Tom

    2015-01-01

    We analysed two groups of Quercus robur trees, growing at nearby plots with different micro-location condition (W-wet and D-dry) in the floodplain Krakovo forest, Slovenia. In the study we compared the growth response of two different tree groups to environmental variables, the potential signal stored in earlywood (EW) structure and the potential difference of the information stored in carbon isotope discrimination of EW and latewood (LW). For that purpose EW and LW widths and carbon isotope discrimination for the period 1970–2008 AD were measured. EW and LW widths were measured on stained microscopic slides and chronologies were standardised using the ARSTAN program. α-cellulose was extracted from pooled EW and LW samples and homogenized samples were further analysed using an elemental analyser and IRMS. We discovered that W oaks grew significantly better over the whole analysed period. The difference between D and W oaks was significant in all analysed variables with the exception of stable carbon isotope discrimination in latewood. In W oaks, latewood widths correlated with summer (June to August) climatic variables, while carbon isotope discrimination was more connected to River Krka flow during the summer. EW discrimination correlated with summer and autumn River Krka flow of the previous year, while latewood discrimination correlated with flow during the current year. In the case of D oaks, the environmental signal appears to be vague, probably due to less favourable growth conditions resulting in markedly reduced increments. Our study revealed important differences in responses to environmental factors between the two oak groups of different physiological conditions that are preconditioned by environmental stress. Environmental information stored in tree-ring features may vary, even within the same forest stand, and largely depends on the micro-environment. Our analysis confirmed our assumptions that separate EW and LW analysis of widths and carbon

  2. Missing Rings, Synchronous Growth, and Ecological Disturbance in a 36-Year Pitch Pine (Pinus rigida) Provenance Study.

    PubMed

    Leland, Caroline; Hom, John; Skowronski, Nicholas; Ledig, F Thomas; Krusic, Paul J; Cook, Edward R; Martin-Benito, Dario; Martin-Fernandez, Javier; Pederson, Neil

    2016-01-01

    Provenance studies are an increasingly important analog for understanding how trees adapted to particular climatic conditions might respond to climate change. Dendrochronological analysis can illuminate differences among trees from different seed sources in terms of absolute annual growth and sensitivity to external growth factors. We analyzed annual radial growth of 567 36-year-old pitch pine (Pinus rigida Mill.) trees from 27 seed sources to evaluate their performance in a New Jersey Pine Barrens provenance experiment. Unexpectedly, missing rings were prevalent in most trees, and some years-1992, 1999, and 2006-had a particularly high frequency of missing rings across the plantation. Trees from local seed sources (<55 km away from the plantation) had a significantly smaller percentage of missing rings from 1980-2009 (mean: 5.0%), relative to northernmost and southernmost sources (mean: 9.3% and 7.9%, respectively). Some years with a high frequency of missing rings coincide with outbreaks of defoliating insects or dry growing season conditions. The propensity for missing rings synchronized annual variations in growth across all trees and might have complicated the detection of potential differences in interannual variability among seed sources. Average ring width was significantly larger in seed sources from both the southernmost and warmest origins compared to the northernmost and coldest seed sources in most years. Local seed sources had the highest average radial growth. Adaptation to local environmental conditions and disturbances might have influenced the higher growth rate found in local seed sources. These findings underscore the need to understand the integrative impact of multiple environmental drivers, such as disturbance agents and climate change, on tree growth, forest dynamics, and the carbon cycle.

  3. Missing Rings, Synchronous Growth, and Ecological Disturbance in a 36-Year Pitch Pine (Pinus rigida) Provenance Study

    PubMed Central

    Leland, Caroline; Hom, John; Skowronski, Nicholas; Krusic, Paul J.; Cook, Edward R.; Martin-Benito, Dario; Martin-Fernandez, Javier; Pederson, Neil

    2016-01-01

    Provenance studies are an increasingly important analog for understanding how trees adapted to particular climatic conditions might respond to climate change. Dendrochronological analysis can illuminate differences among trees from different seed sources in terms of absolute annual growth and sensitivity to external growth factors. We analyzed annual radial growth of 567 36-year-old pitch pine (Pinus rigida Mill.) trees from 27 seed sources to evaluate their performance in a New Jersey Pine Barrens provenance experiment. Unexpectedly, missing rings were prevalent in most trees, and some years—1992, 1999, and 2006—had a particularly high frequency of missing rings across the plantation. Trees from local seed sources (<55 km away from the plantation) had a significantly smaller percentage of missing rings from 1980–2009 (mean: 5.0%), relative to northernmost and southernmost sources (mean: 9.3% and 7.9%, respectively). Some years with a high frequency of missing rings coincide with outbreaks of defoliating insects or dry growing season conditions. The propensity for missing rings synchronized annual variations in growth across all trees and might have complicated the detection of potential differences in interannual variability among seed sources. Average ring width was significantly larger in seed sources from both the southernmost and warmest origins compared to the northernmost and coldest seed sources in most years. Local seed sources had the highest average radial growth. Adaptation to local environmental conditions and disturbances might have influenced the higher growth rate found in local seed sources. These findings underscore the need to understand the integrative impact of multiple environmental drivers, such as disturbance agents and climate change, on tree growth, forest dynamics, and the carbon cycle. PMID:27182599

  4. Telemetry carrier ring and support

    NASA Technical Reports Server (NTRS)

    Wakeman, Thomas G. (Inventor)

    1992-01-01

    A telemetry carrier ring for use in a gas turbine engine includes an annular support ring connected to the engine and an annular carrier ring coupled to the support ring, each ring exhibiting different growth characteristics in response to thermal and mechanical loading. The carrier ring is coupled to the support ring by a plurality of circumferentially spaced web members which are relatively thin in an engine radial direction to provide a predetermined degree of radial flexibility. the web members have a circumferential width and straight axial line of action selected to transfer torque and thrust between the support ring and the carrier ring without substantial deflection. The use of the web members with radial flexibility provides compensation between the support ring and the carrier ring since the carrier ring grows at a different rate than the supporting ring.

  5. Climate variability reflected by tree-ring width and δ18O in a heavily glaciated area of the Patagonian Andes since the Little Ice Age

    NASA Astrophysics Data System (ADS)

    Meier, W. J. H.; Wernicke, J., Jr.; Braun, M.; Aravena, J. C.; Jaña, R.; Griessinger, J.

    2016-12-01

    Since the end of the Little Ice Age, the area of the Northern and Southern Patagonian ice sheet decreased by more than 14% and 11%, respectively. The melting increased since the last decade by 2.3%. The glaciers of Cordillera Darwin recorded a surface decrease of approximately 14% for the last 140 years. The reason for the excessive glacial change is often explained through the rise in temperature combined with a decrease in precipitation or a change in seasonality. Since a spatially coherent coverage of climatological measurement is lacking it is not possible to verify this assumption in a differentiated manner. Hence, the German- Chilean joint project "Responses of GlAciers, Biosphere and hYdrology to climate Variability and climate chAnge across the Southern Andes (GABY-VASA)" aims to determine the influence of long and short term climate variabilities (El Niño-Southern Oscillation (ENSO), Southern Hemisphere Annular Mode (SAM)) on the cryo- and biosphere. Trees growing at the glacier margins and at the natural treeline were sampled at four different locations ranging from the humid western part of the southern Andes (annual precipitation > 10.000mma-1) to the distinct dryer eastern part (annual precipitation < 500mma-1). Besides the tree-ring width based temperature reconstruction the precipitation variability reflected by δ18O in tree-rings is a promising approach to obtain detailed information of small-scaled hydro climatic conditions. Furthermore the use of δ18O as a proxy in combination with tree-ring width offers the opportunity of meteorological back trajectories and the derivation of air masses since the Little Ice Age. It thus interlinks past and present climate and allows to draw conclusions about the driving forces of glacial change.

  6. Tree-ring growth and wood chemistry response to manipulated precipitation variation for two temperate Quercus species

    SciTech Connect

    Wagner, Rebekah J.; Kaye, Margot W.; Abrams, Marc D.; Hanson, Paul J; Martin, Madhavi Z

    2012-01-01

    We examined the relationship among ambient and manipulated precipitation, wood chemistry, and their relationship with radial growth for two oak species in eastern Tennessee. The study took place on the Walker Branch Throughfall Displacement Experiment (TDE) site, located at the Oak Ridge National Laboratory in Oak Ridge, TN. Two dominant species, white oak (Quercus alba) and chestnut oak (Quercus prinus), were selected for study from a 13-year experiment of whole-stand precipitation manipulation (wet, ambient and dry). The relationships between tree-ring width and climate were compared for both species to determine the impact of precipitation manipulations on ring width index. This study used experimental spectroscopy techniques to measure the sensitivity of tree-ring responses to directional changes in precipitation over 13 years, and the results suggest that oaks at this study site are resilient to imposed changes, but sensitive to inter-annual variations in climate. Laser-induced breakdown spectroscopy (LIBS) allowed us to measure nutrient intensities (similar to element concentrations) at 0.5-1.0 mm spacing along the radial growth axis of trees growing in the wet, ambient, and dry treatment sites. A difference in stemwood nutrient levels was observed between the two oak species and among the three treatments. Significant variation in element intensity was observed across treatments for some elements (Ca, K, Mg, Na, N and P) suggesting the potential for long-term impacts on growth under a changing climate regimes for southeastern oaks.

  7. Sierra San Pedro Mártir, Baja California, cool-season precipitation reconstructed from earlywood width of Abies concolor tree rings

    NASA Astrophysics Data System (ADS)

    Meko, D. M.; Touchan, R.; Díaz, J. Villanueva; Griffin, D.; Woodhouse, C. A.; Castro, C. L.; Carillo, C.; Leavitt, S. W.

    2013-12-01

    Tree ring data are analyzed for a multicentury record of drought history in the Sierra San Pedro Mártir (SSPM) of Baja California, Mexico. Climatic variation in the study area is of particular interest because the SSPM is a rich biotic environment at the southern limit of the California floristic province and the southern limit of the planetary jet stream. Future shifts in the jet stream would be expected to have amplified effect on this marginal environment. The study applies linear regression to tree ring indices of earlywood-width of Abies concolor to estimate a 353 year (1658-2010 C.E.) record of cool-season (October-April) precipitation, P, in SSPM. Time-nested regression models account for more than half the variance of grid point P in calibration periods of length 50-65 years. Cross-spectral analysis indicates strong tracking of observed P by the reconstruction over a broad range of frequencies. Robustness of the reconstruction is supported by synchrony of reconstructed P with tree ring variations in other tree species from SSPM. The reconstruction emphasizes the severity of the 1950s drought in a long-term context and the single-year intensity of droughts in the last decade: 2007 stands out as the driest reconstructed year, with a high percentage of missing rings in A. concolor. The reconstruction identifies the early twentieth century pluvial as the wettest epoch in the last 353 years in the SSPM. High-elevation tree species in SSPM may be especially well-suited to sensing snowpack-related moisture variations associated with a southerly branched jet stream and the types of weather systems active in the pluvial.

  8. Early summer temperature reconstruction in the eastern Tibetan plateau since ad 1440 using tree-ring width of Sabina tibetica

    NASA Astrophysics Data System (ADS)

    Zhu, Hai-Feng; Shao, Xue-Mei; Yin, Zhi-Yong; Huang, Lei

    2011-11-01

    Long climate records are scarce on the Tibetan Plateau for understanding the climate variability on long-term context. Here we presented an early summer (May-June) temperature reconstruction since ad 1440 for Qamdo area using tree rings of Sabina tibetica. The reconstruction accounted for 64% of the variance in the instrumental record. It showed warm periods during 1501-1514, 1528-1538, 1598-1609, 1624-1636, 1650-1668, 1695-1705, 1752-1762, 1794-1804, 1878-1890, 1909-1921, 1938-1949, and 1979-1991. Cool early summer occurred during 1440-1454, 1482-1500, 1515-1527, 1576-1597, 1610-1621, 1669-1679, 1706-1716, 1782-1793, 1863-1873, 1894-1908, and 1922-1937. Comparison with other proxy or meteorological records suggested that there is obvious spatial variability in the May-June temperature variations along the eastern margin of the Tibetan Plateau.

  9. Integrating inter- and intra-annual tree-ring width, carbon isotopes and anatomy: responses to climate variability in a temperate oak forest

    NASA Astrophysics Data System (ADS)

    Granda, Elena; Bazot, Stéphane; Fresneau, Chantal; Boura, Anaïs; Faccioni, Georgia; Damesin, Claire

    2015-04-01

    While many forests are experiencing strong tree declines due to climate change in temperate ecosystems, others nearby to those declining show no apparent signs of decline. This could be due to particular microsite conditions or, for instance, to a higher plasticity of given traits that allow a better performance under stressful conditions. We studied oak functional mechanisms (Quercus petraea) leading to the apparently healthy status of the forest and their relation to the observed climatic variability. This study was conducted in the Barbeau Forest (northern France), where cores from mature trees were collected. Three types of functional traits (secondary growth, physiological variables - δ13C and derived Δ13C and iWUE- and several anatomical ones -e.g. vessel area, density-) were recorded for each ring for the 1991-2011 period, distinguishing EW from LW in all measured traits. Among the three types of functional traits, those related to growth experienced the highest variability both between years and between individuals, followed by anatomical and physiological ones. Secondary growth maintained a constant trend during the study period. Instead, ring, EW and LW δ13C slightly declined from 1991 to 2011. Additional intra-ring δ13C analyses allowed for a more detailed understanding of the seasonal dynamics within each year. In particular, the year 2007 (an especially favorable climatic year during the growing season) showed the lowest δ13C values during the EW-LW transition for the whole study period. Inter-annual anatomical traits varied in their responses, but in general, no temporal trends were found. The results from structural equation modeling (SEM) showed direct relationships of seasonal climate and growth, as well as indirect relationships mediated by anatomical and physiological traits. We further discuss the implications of these results on future forest responses to ongoing climate changes.

  10. Product suitability of wood...determined by density gradients across growth rings

    Treesearch

    Robert M. Echols

    1972-01-01

    The suitability of wood for various uses can be determined by synthesizing single growth-ring density curves from accumulated means of wood density classes. Wood density gradients across growth rings were measured in large increment cores from 46-year-old ponderosa pines (Pinus ponderosa Laws.) by using X-rays. Of the 48 trees analyzed, 36 had been...

  11. Temperature reconstruction and volcanic eruption signal from tree-ring width and maximum latewood density over the past 304 years in the southeastern Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Li, Mingqi; Huang, Lei; Yin, Zhi-Yong; Shao, Xuemei

    2017-04-01

    This study presents a 304-year average July-October maximum temperature reconstruction for the Northwest Yunnan Province, southeastern Tibetan Plateau, based on both tree-ring width (TRW) and maximum latewood density (MXD) data from Picea asperata. For the calibration (1958-2005), the MXD and TRW chronologies explained 58% of the variance in July-October maximum temperature. On the decadal scale, two major cold periods occurred during AD 1801-1833 and 1961-2003; and two evident warm periods occurred in AD 1730-1800 and 1928-1960. Comparisons with other reconstructions from the region revealed similar variability patterns on the decadal to longer-term timescales. Based on the reconstructed temperature series and volcanic eruption chronology, we found that most extreme cold years were in good agreement with major volcanic eruptions, such as 1816 after the Tambora eruption in 1815. Also, clusters of volcanic eruptions probably made the 1810s and 1990s the coldest two decades in the past 300 years. Our results indicated that fingerprints of major volcanic eruptions can be found in the reconstructed temperature records in this region, while the responses of regional climate to these eruption events varied in space and time. Moreover, significant periodicities were found in the reconstructed temperature series, including those of 2-7, 10-11 and 16-50 years. Further analysis indicated that sunspot cycle, atmospheric-oceanographic teleconnections such as ENSO and AMO, and volcanic eruptions are all possible factors that influenced the temperature variations in the southeast Tibetan Plateau. Key-words: dendroclimatology, tree-ring, Maximum latewood density, temperature reconstruction, volcanic eruption, Tibetan Plateau

  12. Growth responses to climate in a multi-species tree-ring network in the Western Carpathian Tatra Mountains, Poland and Slovakia.

    PubMed

    Büntgen, Ulf; Frank, David C; Kaczka, Ryszard J; Verstege, Anne; Zwijacz-Kozica, Tomasz; Esper, Jan

    2007-05-01

    We analyzed growth responses to climate of 24 tree-ring width and four maximum latewood density chronologies from the greater Tatra region in Poland and Slovakia. This network comprises 1183 ring-width and 153 density measurement series from four conifer species (Picea abies (L.) Karst., Larix decidua Mill., Abies alba (L.) Karst., and Pinus mugo (L.)) between 800 and 1550 m a.s.l. Individual spline detrending was used to retain annual to multi-decadal scale climate information in the data. Twentieth century temperature and precipitation data from 16 grid-boxes covering the 48-50 degrees N and 19-21 degrees E region were used for comparison. The network was analyzed to assess growth responses to climate as a function of species, elevation, parameter, frequency and site ecology. Twenty ring-width chronologies significantly correlated (P<0.05) with June-July temperatures, whereas the latewood density chronologies were correlated with the April-September temperatures. Climatic effects of the previous-year summer generally did not significantly influence ring formation, whereas site elevation and frequency of growth variations (i.e., inter-annual and decadal) were significant variables in explaining growth response to climate. Response to precipitation increased with decreasing elevation. Correlations between summer temperatures and annual growth rates were lower for Larix decidua than for Picea abies. Principal component analysis identified five dominant eigenvectors that express somewhat contrasting climatic signals. The first principal component contained highest loadings from 11 Picea abies ring-width chronologies and one Pinus mugo ring-width chronology and explained 42% of the network's variance. The mean of these 12 high-elevation chronologies was significantly correlated at 0.62 with June-July temperatures, whereas the mean of three latewood density chronologies, which loaded most strongly on the fourth principal component, significantly correlated at 0.69 with

  13. Long-term change in the sensitivity of tree-ring growth to climate forcing in Larix decidua.

    PubMed

    Carrer, Marco; Urbinati, Carlo

    2006-01-01

    Tree rings are widely used long-term proxy data which, if combined with long-term instrumental climate records, can provide excellent information on global climate variability. This research aimed to determine whether interannual climate-growth responses in Alpine treeline forests are stationary over time. We used tree-ring width chronologies of Larix decidua (European larch) from 17 sites and monthly temperatures and precipitation data for the period 1800-1999. Climate-growth relationships were assessed with correlation and response functions, and their stationarity and consistency over time were measured using moving correlation. Tree-ring chronologies showed similar interannual variations over the last two centuries, suggesting that the same climatic factors synchronously limited growth at most sites. The most sensitive variables showed significant transient responses varying within the time period, indicating a possible deviation from the uniformitarian principle applied to dendroclimatology. If these findings are confirmed in future studies on other species and in other regions, we suggest that time-dependent variables should be taken into account to avoid overestimation of treeline advance, future forest carbon storage in temperature-limited environments and inaccurate reconstruction of past climate variability.

  14. The role of floodplain width and alluvial bar growth as a precursor for the formation of anabranching rivers

    NASA Astrophysics Data System (ADS)

    Morón, S.; Edmonds, D. A.; Amos, K.

    2017-02-01

    Anabranching rivers are defined as a system of multiple channels separated by stable alluvial islands. While substantial progress has been made in developing a physics-based understanding of what drives the differences between meandering and braided river channels, anabranching rivers have not been well-integrated into these models. Here, we propose that alluvial bar growth on the floodplain may be a precursor for the formation of anabranching rivers. Alluvial bar growth strongly depends on the aspect ratio of the flow (width divided by depth) and rivers with wide floodplains have flows with a large aspect ratio. Consistent with this idea, remotely sensed measurements of floodplain width of four rivers from different climatic and tectonic settings show that anabranching river patterns are often associated with relatively wide floodplains. To explore the physics behind that empirical relationship we carried out two sets of morphodynamic numerical simulations using boundary conditions from field-scale modern anabranching rivers spanning different climatic and geologic settings as well as hypothetical floodplain widths. Results from the simulations show that, for a given flood discharge, widening the floodplain changes the river pattern from single channel to multi-threaded with mobile bars to multi-channeled with immobile islands. Multi-channeled patterns arise because the emergence of bars causes flow bifurcation. Subsequent bifurcation instability leads to the emergence of multiple stable channels. As the channels increase their cross-sectional area, shields stresses on intervening bars are reduced until the bars stabilize into islands. We suggest that the presence of stable islands allows vegetation to grow or cohesive sediment to accumulate leading to enhanced channel bank strength and a stable anabranching pattern. Our results suggest that alluvial bar growth can be a precursor to formation of anabranching rivers. Compared with field measurements our simulations

  15. Temperature reconstruction and volcanic eruption signal from tree-ring width and maximum latewood density over the past 304 years in the southeastern Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Li, Mingqi; Huang, Lei; Yin, Zhi-Yong; Shao, Xuemei

    2017-07-01

    This study presents a 304-year mean July-October maximum temperature reconstruction for the southeastern Tibetan Plateau based on both tree-ring width and maximum latewood density data. The reconstruction explained 58% of the variance in July-October maximum temperature during the calibration period (1958-2005). On the decadal scale, we identified two prominent cold periods during AD 1801-1833 and 1961-2003 and two prominent warm periods during AD 1730-1800 and 1928-1960, which are consistent with other reconstructions from the nearby region. Based on the reconstructed temperature series and volcanic eruption chronology, we found that most extreme cold years were in good agreement with major volcanic eruptions, such as 1816 after the Tambora eruption in 1815. Also, clusters of volcanic eruptions probably made the 1810s the coldest decade in the past 300 years. Our results indicated that fingerprints of major volcanic eruptions can be found in the reconstructed temperature records, while the responses of regional climate to these eruption events varied in space and time in the southeastern Tibetan Plateau.

  16. Effects of climatic conditions on annual shoot length and tree-ring width of alpine dwarf pine Pinus pumila in central Japan.

    PubMed

    Takahashi, Koichi; Aoki, Keigo

    2015-07-01

    This study compared the effects of climatic conditions on annual shoot length (ASL) and tree-ring width (TRW) of alpine dwarf pine Pinus pumila in central Japan, by using dendrochronological techniques. Chronologies of ASL (1951-2009) and TRW (1972-2009) were standardized to remove non-climatic signals, and correlation tests were done for non-standardized observed values and standardized indices with monthly temperatures and precipitation. Monthly mean temperatures from March to October, except for July, increased during 1951‒2009; observed values and a standardized index of ASL increased during this period. For the rate of increase in ASL, the standardized index was lower than the observed values. However, these values of TRW showed no trends. The observed values and standardized index of TRW positively correlated with temperatures of the beginning of the growing season of the current year. The observed values of ASL positively correlated with temperatures during the growing season of the previous and current years. However, the standardized index of ASL positively correlated with only June temperatures of the previous and current years. The different results of ASL between observed values and standardized indices indicate that many significant correlations of observed values were attributable to increasing trends of temperature and ASL. This study suggests that standardized ASL of P. pumila tended to increase greater than TRW, that high temperatures at the beginning of the growing season increases ASL and TRW, and that analyzing observed values of ASL may overestimate the effects of temperature on ASL of P. pumila.

  17. Multi-proxy reconstructions of South American precipitation from oxygen isotopes and growth rings in tropical trees

    NASA Astrophysics Data System (ADS)

    Ballantyne, A. P.; Baker, P.; Chambers, J.; Villalba, R.

    2004-12-01

    Most of our knowledge about climate variability is restricted to the high latitudes of the Northern Hemisphere. Although the tropics constitute 40% of the Earth's surface, very little is known about temperature and precipitation variability, even during the last century. By analyzing the growth and isotopic variability of tropical trees, we may resolve intra-annual fluctuations in precipitation. Certain taxa of tropical trees are known to possess annual growth rings and some taxa exceed 1,000 years old. Recent progress in tropical dendrochronology, has established a strong relationship between growth and precipitation amount, especially during the growth season. The relationship between \\delta18O in precipitation and precipitation amount has been well established; and is moderately significant for certain regions of the neotropics (r= -65). Although much of the variability in the \\delta18O of precipitation has been ascribed to changes in sea surface temperatures resulting from El Niño events, longer periods (12 yr.) of variability in \\delta18O remain unexplained. Here we combine measures of tree ring growth and \\delta18O in the cellulose of several tropical trees to capture the inter-annual variability in precipitation. Samples from the Andean genus Polylepis were cross-dated and analyzed for \\delta18O. The resulting 146-year time series reveals pronounced inter-annual variability in \\delta18O, as well as low frequency variability similar to the \\delta18O. An appreciable amount of regional precipitation is described by the ring-width and the high pass-filtered \\delta18O data. To validate the relationship between growth and cellulose \\delta18O, we also analyzed samples from Dipterix spp. and Tachigali spp. from the Amazon. In both taxa growth maxima and cellulose \\delta18O minima coincided during the rainy season (DJF). The analysis of \\delta13C, another isotope known to be fractionated under arid conditions may increase our ability to reconstruct

  18. Ring chromosome 5 associated with severe growth retardation as the sole major physical abnormality

    SciTech Connect

    Migliori, M.V.; Pettinari, A.; Cherubini, V.; Bartolotta, E.; Pecora, R.

    1994-01-01

    The authors report on a case of ring chromosome 5 in a 36-month-old girl with severe growth retardation, clinodactyly, mild psychological abnormalities, and normal facial appearance. Endocrine tests showed partial growth hormone deficiency. Cytogenetic investigation failed to demonstrate any apparent microscopic deletion of either the short or long arm of chromosome 5 as a consequence of ring formation. In 12% of cells examined, the ring was either absent or present in multiple copies. Only 3 previous cases of ring chromosome 5 have been reported in association with short stature of prenatal onset and minor anomalies, without mental retardation. 12 refs., 3 figs.

  19. Tree-ring growth patterns and climatic signals along a vertical transect of larch sites in the Simplon and Rhône Valleys (Switzerland)

    NASA Astrophysics Data System (ADS)

    Riechelmann, Dana F. C.; Esper, Jan

    2017-04-01

    State-of-the-art millennial long temperature reconstructions from the European Alps integrate wood samples of Larix decidua Mill. from the Lötschental and Simplon regions in Switzerland (Büntgen et al., 2005; 2006). Some of the oldest samples that enable the extension of the time-series back into the first millennium AD are obtained from old buildings in Simplon Village, through the precise location of these samples and the elevation of sampling sites remain unknown. We here evaluate the growth characteristics of larch tree-ring width data along a vertical transect in the Simplon and Rhône valleys. 330 trees from nine sites in 985, 1100, 1400, 1575, 1710, 1712, 1900, 2020, and 2150 m asl have been sampled and analysed for their climate signals. The results indicate a stronger temperature signal in the tree-ring width with increasing elevation. The lower the sites the more a drought signal is imprinted in the ring width data. The intermediate site at 1400 m asl does not show any pronounced climate signal. A comparison of growth patterns of living-tree sites with samples from the historical buildings in Simplon Village (Riechelmann et al., 2013) indicates the construction timber to origin from intermediate to higher elevations. We therefore do not expect strong temperature signal from these timbers. References: Büntgen, U., Esper, J., Frank, D.C., Nicolussi, K., Schmidhalter, M., 2005. A 1052-year tree-ring proxy for Alpine summer temperatures. Climate Dynamics 25: 141-153. Büntgen, U., Frank, D.C., Nievergelt, D., Esper J., 2006. Summer temperature variations in the European Alps, A.D. 755-2004. Journal of Climate 19: 5606-5623. Riechelmann, D.F.C., Schmidhalter, M., Büntgen, U., Esper, J., 2013. Extending a high-elevation larch ring width chronology from the Simplon region in the Swiss Alps over the past millenium. TRACE 11:103-108.

  20. Spatiotemporal analysis of sensor logs using growth ring maps.

    PubMed

    Bak, Peter; Mansmann, Florian; Janetzko, Halldor; Keim, Daniel A

    2009-01-01

    Spatiotemporal analysis of sensor logs is a challenging research field due to three facts: a) traditional two-dimensional maps do not support multiple events to occur at the same spatial location, b) three-dimensional solutions introduce ambiguity and are hard to navigate, and c) map distortions to solve the overlap problem are unfamiliar to most users. This paper introduces a novel approach to represent spatial data changing over time by plotting a number of non-overlapping pixels, close to the sensor positions in a map. Thereby, we encode the amount of time that a subject spent at a particular sensor to the number of plotted pixels. Color is used in a twofold manner; while distinct colors distinguish between sensor nodes in different regions, the colors' intensity is used as an indicator to the temporal property of the subjects' activity. The resulting visualization technique, called Growth Ring Maps, enables users to find similarities and extract patterns of interest in spatiotemporal data by using humans' perceptual abilities. We demonstrate the newly introduced technique on a dataset that shows the behavior of healthy and Alzheimer transgenic, male and female mice. We motivate the new technique by showing that the temporal analysis based on hierarchical clustering and the spatial analysis based on transition matrices only reveal limited results. Results and findings are cross-validated using multidimensional scaling. While the focus of this paper is to apply our visualization for monitoring animal behavior, the technique is also applicable for analyzing data, such as packet tracing, geographic monitoring of sales development, or mobile phone capacity planning.

  1. Sensitivity of tree ring growth to local and large-scale climate variability in a region of Southeastern Brazil

    NASA Astrophysics Data System (ADS)

    Venegas-González, Alejandro; Chagas, Matheus Peres; Anholetto Júnior, Claudio Roberto; Alvares, Clayton Alcarde; Roig, Fidel Alejandro; Tomazello Filho, Mario

    2016-01-01

    We explored the relationship between tree growth in two tropical species and local and large-scale climate variability in Southeastern Brazil. Tree ring width chronologies of Tectona grandis (teak) and Pinus caribaea (Caribbean pine) trees were compared with local (Water Requirement Satisfaction Index—WRSI, Standardized Precipitation Index—SPI, and Palmer Drought Severity Index—PDSI) and large-scale climate indices that analyze the equatorial pacific sea surface temperature (Trans-Niño Index-TNI and Niño-3.4-N3.4) and atmospheric circulation variations in the Southern Hemisphere (Antarctic Oscillation-AAO). Teak trees showed positive correlation with three indices in the current summer and fall. A significant correlation between WRSI index and Caribbean pine was observed in the dry season preceding tree ring formation. The influence of large-scale climate patterns was observed only for TNI and AAO, where there was a radial growth reduction in months preceding the growing season with positive values of the TNI in teak trees and radial growth increase (decrease) during December (March) to February (May) of the previous (current) growing season with positive phase of the AAO in teak (Caribbean pine) trees. The development of a new dendroclimatological study in Southeastern Brazil sheds light to local and large-scale climate influence on tree growth in recent decades, contributing in future climate change studies.

  2. Tree growth and its climate signal along latitudinal and altitudinal gradients: comparison of tree rings between Finland and the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Lyu, Lixin; Suvanto, Susanne; Nöjd, Pekka; Henttonen, Helena M.; Mäkinen, Harri; Zhang, Qi-Bin

    2017-06-01

    Latitudinal and altitudinal gradients can be utilized to forecast the impact of climate change on forests. To improve the understanding of how these gradients impact forest dynamics, we tested two hypotheses: (1) the change of the tree growth-climate relationship is similar along both latitudinal and altitudinal gradients, and (2) the time periods during which climate affects growth the most occur later towards higher latitudes and altitudes. To address this, we utilized tree-ring data from a latitudinal gradient in Finland and from two altitudinal gradients on the Tibetan Plateau. We analysed the latitudinal and altitudinal growth patterns in tree rings and investigated the growth-climate relationship of trees by correlating ring-width index chronologies with climate variables, calculating with flexible time windows, and using daily-resolution climate data. High latitude and altitude plots showed higher correlations between tree-ring chronologies and growing season temperature. However, the effects of winter temperature showed contrasting patterns for the gradients. The timing of the highest correlation with temperatures during the growing season at southern sites was approximately 1 month ahead of that at northern sites in the latitudinal gradient. In one out of two altitudinal gradients, the timing for the strongest negative correlation with temperature at low-altitude sites was ahead of treeline sites during the growing season, possibly due to differences in moisture limitation. Mean values and the standard deviation of tree-ring width increased with increasing mean July temperatures on both types of gradients. Our results showed similarities of tree growth responses to increasing seasonal temperature between latitudinal and altitudinal gradients. However, differences in climate-growth relationships were also found between gradients due to differences in other factors such as moisture conditions. Changes in the timing of the most critical climate variables

  3. Wood density of young-growth western hemlock: relation to ring age, radial growth, stand density, and site quality.

    Treesearch

    Dean S. DeBell; Ryan Singleton; Barbara L. Gartner; David D. Marshall

    2004-01-01

    Breast-high stem sections were sampled from 56 western hemlock (Tsuga heterophylla (Raf.) Sarg.) trees growing in 15 plots representing a wide range of tree and site conditions in northwestern Oregon. Growth and wood density traits of individual rings were measured via X-ray densitometry, and relationships of ring density and its components to age...

  4. Tree-ring latewood width based July-August SPEI reconstruction in South China since 1888 and its possible connection with ENSO

    NASA Astrophysics Data System (ADS)

    Zhao, Yesi; Shi, Jiangfeng; Shi, Shiyuan; Yu, Jian; Lu, Huayu

    2017-02-01

    Our understanding of the long-term hydroclimate variations in South China is prohibited by the shortness of meteorological records. Paleoclimatic proxies, such as tree-rings, can be pursued to extend the meteorological records back for centuries to help us better understand hydroclimatic conditions. In this study, we reconstructed the July-August standardized precipitation-evapotranspiration index (SPEIJul-Aug) based on a newly developed 127-yr adjusted latewood width chronology from Tsuga longibracteata, South China. The chronology explained 40% of the actual SPEIJul-Aug variance in the period 1953-2014. The reconstructed SPEIJul-Aug can represent large-scale July-August SPEI variations over South China, including northern Guangxi, Hunan, and Guizhou provinces. From the perspective of the past 127 years, the extreme summer drought in 2013 was not unusual because more extreme drought events occurred in the first half of the 20th century. A significant 2.0-3.6-yr hydroclimatic cycle existed in the reconstruction, which indicated that the SPEIJul-Aug might be driven by El Niño-Southern Oscillation (ENSO). We further checked the time-dependency of the relationship between SPEIJul-Aug and ENSO and found that it was unstable. Their relationship was weak before the 1950s, became significant from the 1950s to early 1990s, and then dropped to be weak again and even out of phase since the early 1990s, which may be attributable to the significant westward extension of the western Pacific subtropical high.

  5. A Picea crassifolia Tree-Ring Width-Based Temperature Reconstruction for the Mt. Dongda Region, Northwest China, and Its Relationship to Large-Scale Climate Forcing.

    PubMed

    Liu, Yu; Sun, Changfeng; Li, Qiang; Cai, Qiufang

    2016-01-01

    The historical May-October mean temperature since 1831 was reconstructed based on tree-ring width of Qinghai spruce (Picea crassifolia Kom.) collected on Mt. Dongda, North of the Hexi Corridor in Northwest China. The regression model explained 46.6% of the variance of the instrumentally observed temperature. The cold periods in the reconstruction were 1831-1889, 1894-1901, 1908-1934 and 1950-1952, and the warm periods were 1890-1893, 1902-1907, 1935-1949 and 1953-2011. During the instrumental period (1951-2011), an obvious warming trend appeared in the last twenty years. The reconstruction displayed similar patterns to a temperature reconstruction from the east-central Tibetan Plateau at the inter-decadal timescale, indicating that the temperature reconstruction in this study was a reliable proxy for Northwest China. It was also found that the reconstruction series had good consistency with the Northern Hemisphere temperature at a decadal timescale. Multi-taper method spectral analysis detected some low- and high-frequency cycles (2.3-2.4-year, 2.8-year, 3.4-3.6-year, 5.0-year, 9.9-year and 27.0-year). Combining these cycles, the relationship of the low-frequency change with the Pacific Decadal Oscillation (PDO), North Atlantic Oscillation (NAO) and Southern Oscillation (SO) suggested that the reconstructed temperature variations may be related to large-scale atmospheric-oceanic variations. Major volcanic eruptions were partly reflected in the reconstructed temperatures after high-pass filtering; these events promoted anomalous cooling in this region. The results of this study not only provide new information for assessing the long-term temperature changes in the Hexi Corridor of Northwest China, but also further demonstrate the effects of large-scale atmospheric-oceanic circulation on climate change in Northwest China.

  6. A Picea crassifolia Tree-Ring Width-Based Temperature Reconstruction for the Mt. Dongda Region, Northwest China, and Its Relationship to Large-Scale Climate Forcing

    PubMed Central

    Liu, Yu; Sun, Changfeng; Li, Qiang; Cai, Qiufang

    2016-01-01

    The historical May–October mean temperature since 1831 was reconstructed based on tree-ring width of Qinghai spruce (Picea crassifolia Kom.) collected on Mt. Dongda, North of the Hexi Corridor in Northwest China. The regression model explained 46.6% of the variance of the instrumentally observed temperature. The cold periods in the reconstruction were 1831–1889, 1894–1901, 1908–1934 and 1950–1952, and the warm periods were 1890–1893, 1902–1907, 1935–1949 and 1953–2011. During the instrumental period (1951–2011), an obvious warming trend appeared in the last twenty years. The reconstruction displayed similar patterns to a temperature reconstruction from the east-central Tibetan Plateau at the inter-decadal timescale, indicating that the temperature reconstruction in this study was a reliable proxy for Northwest China. It was also found that the reconstruction series had good consistency with the Northern Hemisphere temperature at a decadal timescale. Multi-taper method spectral analysis detected some low- and high-frequency cycles (2.3–2.4-year, 2.8-year, 3.4–3.6-year, 5.0-year, 9.9-year and 27.0-year). Combining these cycles, the relationship of the low-frequency change with the Pacific Decadal Oscillation (PDO), North Atlantic Oscillation (NAO) and Southern Oscillation (SO) suggested that the reconstructed temperature variations may be related to large-scale atmospheric-oceanic variations. Major volcanic eruptions were partly reflected in the reconstructed temperatures after high-pass filtering; these events promoted anomalous cooling in this region. The results of this study not only provide new information for assessing the long-term temperature changes in the Hexi Corridor of Northwest China, but also further demonstrate the effects of large-scale atmospheric-oceanic circulation on climate change in Northwest China. PMID:27509206

  7. The influence of summertime fog and overcast clouds on the growth of a coastal Californian pine: a tree-ring study.

    PubMed

    Williams, A Park; Still, Christopher J; Fischer, Douglas T; Leavitt, Steven W

    2008-06-01

    The coast of California is home to numerous rare, endemic conifers and other plants that are limited in distribution by drought sensitivity and the summer-dry climate that prevails across most of the state. Ecologists have long assumed that some coastal plant populations survived the early Pleistocene transition to a warmer and drier environment because they benefit from frequent fog and stratus clouds that provide water and shade during the rainless summer. One such population is that of Torrey pine (Pinus torreyana ssp. Insularis) on Santa Rosa Island in Channel Islands National Park. Here we report that the tree-ring width record from this population indicates strong growth sensitivities to summer fog drip and cloud shading. We quantified the effects of summer cloud cover by comparing ring-width indices to coastal airport cloud-frequency records (1944-2004). For the first time observed, summertime cloud frequency correlated positively with ring-width indices, regardless of whether the effect of rainfall was first removed from the ring-width record. The effect of ground-level fog was strongest in July early mornings (03:00 PST, R(2) = 0.262, P < 0.0002). The effect of clouds high enough to provide shade but not fog water was also strongest in July, but climbed steadily throughout the day before becoming strongest in late afternoon (16:00-18:00 PST, R(2) = 0.148, P < 0.004). Correlations were substantially stronger in years with higher soil moisture, suggesting that growth response to summer clouds is strongly affected by pre-summer rainfall. A change in the height and/or timing of coastal cloud formation with climate change would likely affect this and other populations of California's coastal vegetation.

  8. Ozone air pollution effects on tree-ring growth, delta(13)C, visible foliar injury and leaf gas exchange in three ozone-sensitive woody plant species.

    PubMed

    Novak, Kristopher; Cherubini, Paolo; Saurer, Matthias; Fuhrer, Jürg; Skelly, John M; Kräuchi, Norbert; Schaub, Marcus

    2007-07-01

    We assessed the effects of ambient tropospheric ozone on annual tree-ring growth, delta(13)C in the rings, leaf gas exchange and visible injury in three ozone-sensitive woody plant species in southern Switzerland. Seedlings of Populus nigra L., Viburnum lantana L. and Fraxinus excelsior L. were exposed to charcoal-filtered air (CF) and non-filtered air (NF) in open-top chambers, and to ambient air (AA) in open plots during the 2001 and 2002 growing seasons. Ambient ozone exposures in the region were sufficient to cause visible foliar injury, early leaf senescence and premature leaf loss in all species. Ozone had significant negative effects on net photosynthesis and stomatal conductance in all species in 2002 and in V. lantana and F. excelsior in 2001. Water-use efficiency decreased and intercellular CO(2) concentrations increased in all species in response to ozone in 2002 only. The width and delta(13)C of the 2001 and 2002 growth rings were measured for all species at the end of the 2002 growing season. Compared with CF seedlings, mean ring width in the AA and NF P. nigra seedlings was reduced by 52 and 46%, respectively, in 2002, whereas in V. lantana and F. excelsior, ring width showed no significant reductions in either year. Although delta(13)C was usually more negative in CF seedlings than in AA and NF seedlings, with the exception of F. excelsior in 2001, ozone effects on delta(13)C were significant only for V. lantana and P. nigra in 2001. Among species, P. nigra exhibited the greatest response to ozone for the measured parameters as well as the most severe foliar injury and was the only species to show a significant reduction in ring width in response to ozone exposure, despite significant negative ozone effects on leaf gas exchange and the development of visible foliar injury in V. lantana and F. excelsior. Thus, significant ozone-induced effects at the leaf level did not correspond to reduced tree-ring growth or increased delta(13)C in all species

  9. Growth cessation uncouples isotopic signals in leaves and tree rings of drought-exposed oak trees.

    PubMed

    Pflug, Ellen E; Siegwolf, R; Buchmann, N; Dobbertin, M; Kuster, T M; Günthardt-Goerg, M S; Arend, M

    2015-10-01

    An increase in temperature along with a decrease in summer precipitation in Central Europe will result in an increased frequency of drought events and gradually lead to a change in species composition in forest ecosystems. In the present study, young oaks (Quercus robur L. and Quercus petraea (Matt.) Liebl.) were transplanted into large mesocosms and exposed for 3 years to experimental warming and a drought treatment with yearly increasing intensities. Carbon and oxygen isotopic (δ(13)C and δ(18)O) patterns were analysed in leaf tissue and tree-ring cellulose and linked to leaf physiological measures and tree-ring growth. Warming had no effect on the isotopic patterns in leaves and tree rings, while drought increased δ(18)O and δ(13)C. Under severe drought, an unexpected isotopic pattern, with a decrease in δ(18)O, was observed in tree rings but not in leaves. This decrease in δ(18)O could not be explained by concurrent physiological analyses and is not supported by current physiological knowledge. Analysis of intra-annual tree-ring growth revealed a drought-induced growth cessation that interfered with the record of isotopic signals imprinted on recently formed leaf carbohydrates. This missing record indicates isotopic uncoupling of leaves and tree rings, which may have serious implications for the interpretation of tree-ring isotopes, particularly from trees that experienced growth-limiting stresses.

  10. Chaparral growth-ring analysis as an indicator of stand biomass development

    Treesearch

    Kellie A. Uyeda; Douglas A. Stow; John F. O' Leary; Christina Tague; Philip J. Riggan

    2016-01-01

    Chaparral wildfires typically create even-aged stands of vegetation that grow quickly in the first 2 decades following a fire. Patterns of this growth are important for understanding ecosystem productivity and re-establishment success, but are logistically challenging to measure over long time periods. We tested the utility of a novel method of using shrub growth rings...

  11. Tree demography dominates long-term growth trends inferred from tree rings.

    PubMed

    Brienen, Roel J W; Gloor, Manuel; Ziv, Guy

    2017-02-01

    Understanding responses of forests to increasing CO2 and temperature is an important challenge, but no easy task. Tree rings are increasingly used to study such responses. In a recent study, van der Sleen et al. (2014) Nature Geoscience, 8, 4 used tree rings from 12 tropical tree species and find that despite increases in intrinsic water use efficiency, no growth stimulation is observed. This challenges the idea that increasing CO2 would stimulate growth. Unfortunately, tree ring analysis can be plagued by biases, resulting in spurious growth trends. While their study evaluated several biases, it does not account for all. In particular, one bias may have seriously affected their results. Several of the species have recruitment patterns, which are not uniform, but clustered around one specific year. This results in spurious negative growth trends if growth rates are calculated in fixed size classes, as 'fast-growing' trees reach the sampling diameter earlier compared to slow growers and thus fast growth rates tend to have earlier calendar dates. We assessed the effect of this 'nonuniform age bias' on observed growth trends and find that van der Sleen's conclusions of a lack of growth stimulation do not hold. Growth trends are - at least partially - driven by underlying recruitment or age distributions. Species with more clustered age distributions show more negative growth trends, and simulations to estimate the effect of species' age distributions show growth trends close to those observed. Re-evaluation of the growth data and correction for the bias result in significant positive growth trends of 1-2% per decade for the full period, and 3-7% since 1950. These observations, however, should be taken cautiously as multiple biases affect these trend estimates. In all, our results highlight that tree ring studies of long-term growth trends can be strongly influenced by biases if demographic processes are not carefully accounted for. © 2016 The Authors. Global Change

  12. Radiocarbon evidence for annual growth rings in a deep sea octocoral (Primnoa resedaeformis)

    SciTech Connect

    Sherwood, O A; Scott, D B; Risk, M J; Guilderson, T P

    2005-04-05

    The deep-sea gorgonian octocoral Primnoa resedaeformis is distributed throughout the Atlantic and Pacific Oceans at depths of 65-3200 m. It has a two-part skeleton of calcite and gorgonin. Towards the inside of the axial skeleton gorgonin and calcite are deposited in concentric growth rings, similar to tree rings. Colonies were collected from the Northeast Channel (northwest Atlantic Ocean, southwest of Nova Scotia, Canada) from depths of 250-475 m. Radiocarbon was measured in individual rings isolated from sections of each colony, after dissolution of calcite. Each {Delta}{sup 14}C measurement was paired with a ring age determined by three amateur ring counters. The precision of ring counts averaged better than {+-} 2 years. Accurate reconstruction of 20th century bomb-radiocarbon shows that (1) the growth rings are formed annually, (2) the gorgonin is derived from surface particulate organic matter (POM) and (3) useful environmental data are recorded in the organic endoskeletons of deep-sea octocorals. These results support the use of Primnoa resedaeformis as a long-term, high resolution monitor of surface ocean conditions, particularly in temperate and boreal environments where proxy data are lacking.

  13. Double hexagonal graphene ring synthesized using a growth-etching method

    NASA Astrophysics Data System (ADS)

    Liu, Jinyang; Xu, Yangyang; Cai, Hongbing; Zuo, Chuandong; Huang, Zhigao; Lin, Limei; Guo, Xiaomin; Chen, Zhendong; Lai, Fachun

    2016-07-01

    Precisely controlling the layer number, stacking order, edge configuration, shape and structure of graphene is extremely challenging but highly desirable in scientific research. In this report, a new concept named the growth-etching method has been explored to synthesize a graphene ring using the chemical vapor deposition process. The graphene ring is a hexagonal structure, which contains a hexagonal exterior edge and a hexagonal hole in the centre region. The most important concept introduced here is that the oxide nanoparticle derived from annealing is found to play a dual role. Firstly, it acts as a nucleation site to grow the hexagonal graphene domain and then it works as a defect for etching to form a hole. The evolution process of the graphene ring with the etching time was carefully studied. In addition, a double hexagonal graphene ring was successfully synthesized for the first time by repeating the growth-etching process, which not only confirms the validity and repeatability of the method developed here but may also be further extended to grow unique graphene nanostructures with three, four, or even tens of graphene rings. Finally, a schematic model was drawn to illustrate how the double hexagonal graphene ring is generated and propagated. The results shown here may provide valuable guidance for the design and growth of unique nanostructures of graphene and other two-dimensional materials.

  14. Graphene Layer Growth Chemistry: Five-Six-Ring Flip Reaction

    SciTech Connect

    Whitesides, Russell; Domin, Dominik; Lester Jr., William A.; Frenklach, Michael

    2007-03-24

    A theoretical study revealed a new reaction pathway, in which a fused five and six-membered ring complex on the zigzag edge of a graphene layer isomerizes to reverse its orientation, or 'flips,' after activation by a gaseous hydrogen atom. The process is initiated by hydrogen addition to or abstraction from the surface complex. The elementary steps of the migration pathway were analyzed using density-functional theory (DFT) calculations to examine the region of the potential energy surface associated with the pathway. The DFT calculations were performed on substrates modeled by the zigzag edges of tetracene and pentacene. Rate constants for the flip reaction were obtained by the solution of energy master equation utilizing the DFT energies, frequencies, and geometries. The results indicate that this reaction pathway is competitive with other pathways important to the edge evolution of aromatic species in high temperature environments.

  15. Growth ring analysis of fossil coniferous woods from early cretaceous of Araripe Basin.

    PubMed

    Pires, Etiene F; Guerra-Sommer, Margot

    2011-06-01

    Growth ring analysis on silicified coniferous woods from the Missão Velha Formation (Araripe Basin - Brazil) has yielded important information about periodicity of wood production during the Early Cretaceous in the equatorial belt. Despite warm temperatures, dendrological data indicate that the climate was characterized by cyclical alternation of dry and rainy periods influenced by cyclical precipitations, typical of tropical wet and dry or savanna climate. The abundance of false growth rings can be attributed to both occasional droughts and arthropod damage. The present climate data agree with palaeoclimatic models that inferred summer-wet biomes for the Late Jurassic/Early Cretaceous boundary in the southern equatorial belt.

  16. Age determination and growth rate of Mactra chinensis (Bivalvia: Mactridae) by external rings and chondrophore growth bands

    NASA Astrophysics Data System (ADS)

    Kim, Jung Yeon; Na, Jong Hun; Oh, Chul-Woong

    2016-12-01

    Age, growth and mortality of Mactra chinensis were investigated during the period from October 2012 to September 2013 in Busan, South Korea. The monthly variation of the marginal index (MI) of the shell and chondrophore showed that the ring of this species was formed once a year during July. We estimated the age of M. chinensis by reading the external rings on the shell and the growth bands of the chondrophore to compare growth parameters between the two growth characters. The age of this species ranged from 0 to 8 years (shell-based age reading) and from 0 to 10 years (chondrophore-based age reading). Based on external rings and growth bands of chondrophore for the same period, the von Bertalanffy growth functions were expressed by the equation, L t = 101.53[1-exp {-0.15( t + 0.75)}] and L t = 90.03[1-exp {-0.20( t + 0.50)}], respectively. The likelihood test showed that there was a significant difference in L ∞ ( P < 0.001), K ( P < 0.001), to ( P < 0.001) estimated from non-linear regression between the two growth characters.

  17. Age trends in tree ring growth and isotopic archives: A case study of Pinus sylvestris L. from northwestern Norway

    NASA Astrophysics Data System (ADS)

    Young, Giles H. F.; Demmler, Joanne C.; Gunnarson, BjöRn E.; Kirchhefer, Andreas J.; Loader, Neil J.; McCarroll, Danny

    2011-06-01

    Measurements of tree ring width and relative density have contributed significantly to many of the large-scale reconstructions of past climatic change, but to extract the climate signal it is first necessary to remove any nonclimatic age-related trends. This detrending can limit the lower-frequency climate information that may be extracted from the archive (the "segment length curse"). This paper uses a data set of ring widths, maximum latewood density and stable carbon and oxygen isotopes from 28 annually resolved series of known-age Pinus sylvestris L. trees in northwestern Norway to test whether stable isotopes in tree rings require an equivalent statistical detrending. Results indicate that stable oxygen and carbon isotope ratios from tree rings whose cambial age exceeds c.50 years exhibit no significant age trends and thus may be used to reconstruct environmental variability and physiological processes at this site without the potential loss of low-frequency information associated with detrending.

  18. Propagation of vortex rings and starting plumes in high and low g. [during crystal growth

    NASA Technical Reports Server (NTRS)

    Hallett, J.

    1988-01-01

    The propagation of vortex rings and starting plumes during crystal growth in supercooled solutions was investigated in variable gravity environment created by acceleration-deceleration routine of a NASA's KC-135 flight. A specially designed crystal growth cell was used to study convection around crystals growing in supersaturated solutions of Na2SO4 and NaCl aboard the NASA KC-135. The results of vertical velocity measurements have shown that a continuously fed plume attains a higher velocity than the individual vortex ring. The results also indicated that the vortex ring decelerates as it propagates, and slows down much more rapidly than the starting plume, indicating a less efficient transport. It is suggested that inertial effects and buoyancy effects on vortex and plume propagation can be separated in the controlled environment of a Space Station borne centrifuge.

  19. Capturing spiral radial growth of conifers using the superellipse to model tree-ring geometric shape.

    PubMed

    Shi, Pei-Jian; Huang, Jian-Guo; Hui, Cang; Grissino-Mayer, Henri D; Tardif, Jacques C; Zhai, Li-Hong; Wang, Fu-Sheng; Li, Bai-Lian

    2015-01-01

    Tree-rings are often assumed to approximate a circular shape when estimating forest productivity and carbon dynamics. However, tree rings are rarely, if ever, circular, thereby possibly resulting in under- or over-estimation in forest productivity and carbon sequestration. Given the crucial role played by tree ring data in assessing forest productivity and carbon storage within a context of global change, it is particularly important that mathematical models adequately render cross-sectional area increment derived from tree rings. We modeled the geometric shape of tree rings using the superellipse equation and checked its validation based on the theoretical simulation and six actual cross sections collected from three conifers. We found that the superellipse better describes the geometric shape of tree rings than the circle commonly used. We showed that a spiral growth trend exists on the radial section over time, which might be closely related to spiral grain along the longitudinal axis. The superellipse generally had higher accuracy than the circle in predicting the basal area increment, resulting in an improved estimate for the basal area. The superellipse may allow better assessing forest productivity and carbon storage in terrestrial forest ecosystems.

  20. Capturing spiral radial growth of conifers using the superellipse to model tree-ring geometric shape

    PubMed Central

    Shi, Pei-Jian; Huang, Jian-Guo; Hui, Cang; Grissino-Mayer, Henri D.; Tardif, Jacques C.; Zhai, Li-Hong; Wang, Fu-Sheng; Li, Bai-Lian

    2015-01-01

    Tree-rings are often assumed to approximate a circular shape when estimating forest productivity and carbon dynamics. However, tree rings are rarely, if ever, circular, thereby possibly resulting in under- or over-estimation in forest productivity and carbon sequestration. Given the crucial role played by tree ring data in assessing forest productivity and carbon storage within a context of global change, it is particularly important that mathematical models adequately render cross-sectional area increment derived from tree rings. We modeled the geometric shape of tree rings using the superellipse equation and checked its validation based on the theoretical simulation and six actual cross sections collected from three conifers. We found that the superellipse better describes the geometric shape of tree rings than the circle commonly used. We showed that a spiral growth trend exists on the radial section over time, which might be closely related to spiral grain along the longitudinal axis. The superellipse generally had higher accuracy than the circle in predicting the basal area increment, resulting in an improved estimate for the basal area. The superellipse may allow better assessing forest productivity and carbon storage in terrestrial forest ecosystems. PMID:26528316

  1. The influence of sampling design on tree-ring-based quantification of forest growth.

    PubMed

    Nehrbass-Ahles, Christoph; Babst, Flurin; Klesse, Stefan; Nötzli, Magdalena; Bouriaud, Olivier; Neukom, Raphael; Dobbertin, Matthias; Frank, David

    2014-09-01

    Tree-rings offer one of the few possibilities to empirically quantify and reconstruct forest growth dynamics over years to millennia. Contemporaneously with the growing scientific community employing tree-ring parameters, recent research has suggested that commonly applied sampling designs (i.e. how and which trees are selected for dendrochronological sampling) may introduce considerable biases in quantifications of forest responses to environmental change. To date, a systematic assessment of the consequences of sampling design on dendroecological and-climatological conclusions has not yet been performed. Here, we investigate potential biases by sampling a large population of trees and replicating diverse sampling designs. This is achieved by retroactively subsetting the population and specifically testing for biases emerging for climate reconstruction, growth response to climate variability, long-term growth trends, and quantification of forest productivity. We find that commonly applied sampling designs can impart systematic biases of varying magnitude to any type of tree-ring-based investigations, independent of the total number of samples considered. Quantifications of forest growth and productivity are particularly susceptible to biases, whereas growth responses to short-term climate variability are less affected by the choice of sampling design. The world's most frequently applied sampling design, focusing on dominant trees only, can bias absolute growth rates by up to 459% and trends in excess of 200%. Our findings challenge paradigms, where a subset of samples is typically considered to be representative for the entire population. The only two sampling strategies meeting the requirements for all types of investigations are the (i) sampling of all individuals within a fixed area; and (ii) fully randomized selection of trees. This result advertises the consistent implementation of a widely applicable sampling design to simultaneously reduce uncertainties in

  2. Widely tunable, narrow line width and low optical noise continuous-wave all fiber Er:Yb co-doped double-clad ring laser

    NASA Astrophysics Data System (ADS)

    Guesmi, Khmaies; Bahloul, Faouzi; Semaan, Georges; Meng, Yichang; Salhi, Mohamed; Sanchez, François

    2017-01-01

    In this paper, we report a widely tunable, narrow linewidth, low noise continuous-wave double-clad Er:Yb doped fiber ring laser. Tunability is demonstrated in wide range spanning from 1520 to almost 1620 nm covering the C and L spectral bands. The cavity design is optimized in order to achieve the largest tuning range with very high optical signal-to-noise ratio (SNR). The output coupling ratio greatly influences the tuning range of the laser while the position of the spectral filter determines the SNR. The obtained laser exhibits a tuning range over 98 nm with a nearly constant SNR of about 58.5 dB.

  3. Effect of plate width on the growth and coalescence of fatigue cracks in plate-to-plate welded T-joints

    SciTech Connect

    Yee, R.; Burns, D.J.; Lambert, S.B.; Lecsek, R.L.; Mohaupt, U.H.

    1995-12-31

    The effect of plate width on the initiation and propagation of fatigue cracks in plate-to-plate T-joints with loading transverse attachment plates and flat fillet-like weld profiles was investigated in a series of constant amplitude fatigue tests. There was no observable effect of plate width on initiation life, propagating life, or total fatigue life, but plate width had a significant effect on crack shape development and crack growth rates. More cracks initiated along the weld toes of wider joints. As a result, the aspect ratios of dominant surface cracks were lower in wider joints, and the dominant surface cracks propagated faster through the thickness of wider base plates. However, there was a greater propensity for edge cracking in narrower specimens because fatigue cracks initiated closer to the free edges of such joints. This offset the faster growth of dominant surface cracks in wider joints so that there was no net effect of plate width on propagation life. A multiple crack linear elastic fracture mechanics model successfully simulated these differences in crack shape development behavior.

  4. Reconstructions of spring/summer precipitation for the Eastern Mediterranean from tree-ring widths and its connection to large-scale atmospheric circulation

    NASA Astrophysics Data System (ADS)

    Touchan, Ramzi; Xoplaki, Elena; Funkhouser, Gary; Luterbacher, Jürg; Hughes, Malcolm K.; Erkan, Nesat; Akkemik, Ünal; Stephan, Jean

    2005-07-01

    This study represents the first large-scale systematic dendroclimatic sampling focused on developing chronologies from different species in the eastern Mediterranean region. Six reconstructions were developed from chronologies ranging in length from 115 years to 600 years. The first reconstruction (1885-2000) was derived from principal components (PCs) of 36 combined chronologies. The remaining five, 1800-2000, 1700-2000, 1600-2000, 1500-2000 and 1400-2000 were developed from PCs of 32, 18, 14, 9, and 7 chronologies, respectively. Calibration and verification statistics for the period 1931-2000 show good levels of skill for all reconstructions. The longest period of consecutive dry years, defined as those with less than 90% of the mean of the observed May-August precipitation, was 5 years (1591-1595) and occurred only once during the last 600 years. The longest reconstructed wet period was 5 years (1601-1605 and 1751-1755). No long term trends were found in May-August precipitation during the last few centuries. Regression maps are used to identify the influence of large-scale atmospheric circulation on regional precipitation. In general, tree-ring indices are influenced by May-August precipitation, which is driven by anomalous below (above) normal pressure at all atmospheric levels and by convection (subsidence) and small pressure gradients at sea level. These atmospheric conditions also control the anomaly surface air temperature distribution which indicates below (above) normal values in the southern regions and warmer (cooler) conditions north of around 40°N. A compositing technique is used to extract information on large-scale climate signals from extreme wet and dry summers for the second half of the twentieth century and an independent reconstruction over the last 237 years. Similar main modes of atmospheric patterns and surface air temperature distribution related to extreme dry and wet summers were identified both for the most recent 50 years and the last

  5. February-May temperature reconstruction based on tree-ring widths of Abies fargesii from the Shennongjia area in central China.

    PubMed

    Zheng, Yonghong; Shao, Xuemei; Lu, Fei; Li, Yan

    2016-08-01

    February-May temperature strongly affects ecological processes and socio-economics in central China, yet its long-term variability has not been thoroughly assessed due to the shortness of instrumental records. In order to improve the understanding of the regularities of temperature variability in central China, in this study, we present a new tree-ring chronology from the Shengnongjia Mountains in central China which provides a valuable 245-year record of temperature variability. The reconstructed temperature correlated strongly with February-May mean temperature records of the Fangxian meteorological station from AD 1958 to AD 2011, and the derived reconstruction explained 44.5 % of the instrumental temperature variation during this period. The study shows that this region experienced three warm periods and two cool periods, i.e., the major warm periods occurred in AD 1783-1806, AD 1879-1909, and AD 1975 to the present, whereas the cool intervals occurred in AD 1807-1878 and AD 1910-1974. This reconstruction could aid in the evaluation of regional climate variability in subtropical China.

  6. Individualistic and Time-Varying Tree-Ring Growth to Climate Sensitivity

    PubMed Central

    Carrer, Marco

    2011-01-01

    The development of dendrochronological time series in order to analyze climate-growth relationships usually involves first a rigorous selection of trees and then the computation of the mean tree-growth measurement series. This study suggests a change in the perspective, passing from an analysis of climate-growth relationships that typically focuses on the mean response of a species to investigating the whole range of individual responses among sample trees. Results highlight that this new approach, tested on a larch and stone pine tree-ring dataset, outperforms, in terms of information obtained, the classical one, with significant improvements regarding the strength, distribution and time-variability of the individual tree-ring growth response to climate. Moreover, a significant change over time of the tree sensitivity to climatic variability has been detected. Accordingly, the best-responder trees at any one time may not always have been the best-responders and may not continue to be so. With minor adjustments to current dendroecological protocol and adopting an individualistic approach, we can improve the quality and reliability of the ecological inferences derived from the climate-growth relationships. PMID:21829523

  7. Disruption of insulin-like growth factor-I expression in type IIαI collagen-expressing cells reduces bone length and width in mice

    PubMed Central

    Govoni, Kristen E.; Lee, Seong Keun; Chung, Yoon-Sok; Behringer, Richard R.; Wergedal, Jon E.; Baylink, David J.; Mohan, Subburaman

    2010-01-01

    It is well established that insulin-like growth factor (IGF)-I is critical for the regulation of peak bone mineral density (BMD) and bone width. However, the role of systemic vs. local IGF-I is not well understood. To determine the role local IGF-I plays in regulating BMD and bone width, we crossed IGF-I flox/flox mice with procollagen, typeIIαI-Cre mice to generate conditional mutants in which chondrocyte-derived IGF-I was disrupted. Bone parameters were measured by dual X-ray absorptiometry at 2, 4, 8, and 12 wk of age and peripheral quantitative computed tomography at 12 wk of age. Body length, areal BMD, and bone mineral content (BMC) were reduced (P < 0.05) between 4 and 12 wk in the conditional mutant mice. Bone width was reduced 7% in the vertebrae and femur (P < 0.05) of conditional mutant mice at 12 wk. Gains in body length and total body BMC and BMD were reduced by 27, 22, and 18%, respectively (P < 0.05) in conditional mutant mice between 2 and 4 wk of age. Expression of parathyroid hormone related protein, parathyroid hormone receptor, distal-less homeobox (Dlx)-5, SRY-box containing gene-9, and IGF binding protein (IGFBP)-5 were reduced 27, 36, 45, 33, and 45%, respectively, in the conditional mutant cartilage (P < 0.05); however, no changes in Indian hedgehog, Dlx-3, growth hormone receptor, IGF-I receptor, and IGFBP-3 expression were observed (P ≥ 0.20). In conclusion, IGF-I from cells expressing procollagen type IIαI regulates bone accretion that occurs during postnatal growth period. PMID:17519362

  8. Mongolian tree rings and 20th-century warming

    SciTech Connect

    Jacoby, G.C.; D`Arrigo, R.D.; Davaajamts, T.

    1996-08-09

    A 450-year tree-ring width chronology of Siberian pine (Pinus sibirica Du Tour) growing at timberline (2450 meters) in the Tarvagatay Mountains in west central Mongolia shows wide annual growth rings for the recent century. Ecological site observations and comparisons with instrumental temperature records indicate that the ring widths of these trees are sensitive to annual temperature variations. Low-frequency variations in the Tarvagatay tree-ring record are similar to those in a reconstruction of Arctic annual temperatures, which is based on 20 tree-ring width series from northern North America, Scandinavia, and western Russia. The results indicate that recent warming is unusual relative to temperatures of the past 450 years. 29 refs., 2 figs.

  9. Role of re-growth interface preparation process for spectral line-width reduction of single InAs site-controlled quantum dots.

    PubMed

    Herranz, Jesús; Wewior, Lukasz; Alén, Benito; Fuster, David; González, Luisa; González, Yolanda

    2015-05-15

    We present growth and optical characterization measurements of single InAs site-controlled quantum dots (SCQDs) grown by molecular beam epitaxy on GaAs (001) patterned substrates by atomic force microscopy oxidation lithography. InAs SCQDs directly grown on the patterned surface were used as a seed layer and strain template for the nucleation of optically active single InAs SCQDs. The preservation of the initial geometry of the engraved pattern motifs after the re-growth interface preparation process, the lack of buffer layer growth prior to InAs seed layer deposition and the development of suitable growth conditions provide us an improvement of the SCQDs' active layer optical properties while retaining a high ratio of single occupation (89%). In this work a fivefold reduction of the average optical line-width from 870 μeV to 156 μeV for InAs SCQDs located 15 nm from the re-growth interface is obtained by increasing the temperature of the initial thermal treatment step of the re-growth interface from 490 °C to 530 °C.

  10. North Pacific climate recorded in growth rings of geoduck clams: A new tool for paleoenvironmental reconstruction

    NASA Astrophysics Data System (ADS)

    Strom, Are; Francis, Robert C.; Mantua, Nathan J.; Miles, Edward L.; Peterson, David L.

    2004-03-01

    To better understand North Pacific climate variability at interannual to interdecadal scales, we have developed a new tool for paleoenvironmental reconstruction. We show that growth rings in long-lived geoduck clams (Panopea abrupta) can provide high quality, annually resolved records of sea-surface temperature (SST). We used shell samples from the Strait of Juan de Fuca, in Washington State, to extend the coastal SST record back to 1877. The spatial correlation pattern between the growth index and gridded SSTs bears a strong resemblance to the leading pattern of interdecadal global SST variations and underscores the remarkable long-distance coherence evident among coastal SST records in the northeast Pacific. Our results also indicate that the 1990s was the warmest decade in this region since at least the 1850s.

  11. Long Tree-Ring Chronologies Provide Evidence of Recent Tree Growth Decrease in a Central African Tropical Forest

    PubMed Central

    Battipaglia, Giovanna; Zalloni, Enrica; Castaldi, Simona; Marzaioli, Fabio; Cazzolla- Gatti, Roberto; Lasserre, Bruno; Tognetti, Roberto; Marchetti, Marco; Valentini, Riccardo

    2015-01-01

    It is still unclear whether the exponential rise of atmospheric CO2 concentration has produced a fertilization effect on tropical forests, thus incrementing their growth rate, in the last two centuries. As many factors affect tree growth patterns, short -term studies might be influenced by the confounding effect of several interacting environmental variables on plant growth. Long-term analyses of tree growth can elucidate long-term trends of plant growth response to dominant drivers. The study of annual rings, applied to long tree-ring chronologies in tropical forest trees enables such analysis. Long-term tree-ring chronologies of three widespread African species were measured in Central Africa to analyze the growth of trees over the last two centuries. Growth trends were correlated to changes in global atmospheric CO2 concentration and local variations in the main climatic drivers, temperature and rainfall. Our results provided no evidence for a fertilization effect of CO2 on tree growth. On the contrary, an overall growth decline was observed for all three species in the last century, which appears to be significantly correlated to the increase in local temperature. These findings provide additional support to the global observations of a slowing down of C sequestration in the trunks of forest trees in recent decades. Data indicate that the CO2 increase alone has not been sufficient to obtain a tree growth increase in tropical trees. The effect of other changing environmental factors, like temperature, may have overridden the fertilization effect of CO2. PMID:25806946

  12. Long tree-ring chronologies provide evidence of recent tree growth decrease in a Central African tropical forest.

    PubMed

    Battipaglia, Giovanna; Zalloni, Enrica; Castaldi, Simona; Marzaioli, Fabio; Cazzolla-Gatti, Roberto; Lasserre, Bruno; Tognetti, Roberto; Marchetti, Marco; Valentini, Riccardo

    2015-01-01

    It is still unclear whether the exponential rise of atmospheric CO2 concentration has produced a fertilization effect on tropical forests, thus incrementing their growth rate, in the last two centuries. As many factors affect tree growth patterns, short -term studies might be influenced by the confounding effect of several interacting environmental variables on plant growth. Long-term analyses of tree growth can elucidate long-term trends of plant growth response to dominant drivers. The study of annual rings, applied to long tree-ring chronologies in tropical forest trees enables such analysis. Long-term tree-ring chronologies of three widespread African species were measured in Central Africa to analyze the growth of trees over the last two centuries. Growth trends were correlated to changes in global atmospheric CO2 concentration and local variations in the main climatic drivers, temperature and rainfall. Our results provided no evidence for a fertilization effect of CO2 on tree growth. On the contrary, an overall growth decline was observed for all three species in the last century, which appears to be significantly correlated to the increase in local temperature. These findings provide additional support to the global observations of a slowing down of C sequestration in the trunks of forest trees in recent decades. Data indicate that the CO2 increase alone has not been sufficient to obtain a tree growth increase in tropical trees. The effect of other changing environmental factors, like temperature, may have overridden the fertilization effect of CO2.

  13. Growth mechanism of α-SiC hetero-epitaxial films by PLD as studied on the laser photon, pulse-width and substrates dependence

    NASA Astrophysics Data System (ADS)

    Muto, Hachizo; Kamiya, Shin-ichiro; Kusumori, Takeshi

    2003-07-01

    Hetero-epitaxial films of α-SiC (high-temperature type) were successfully fabricated by pulsed laser ablation-deposition (PLD) at much lower temperatures than the transition temperature ( Tc˜1600 °C) from β-SiC. Since the preparation of the epitaxial films which may be used instead of single-crystal wafers is a very important subject in SiC device technology, we have studied on the laser photon and pulse-width dependence using nanosecond and picosecond Nd:YAG lasers in addition to the temperature and substrate dependence. It is necessary for epitaxial growth of SiC to use a suitable (not so high) fluence, photon energy and pulse width in addition to heater temperature of 1200-1300 °C and symmetry (C 6) matching between substrates and SiC. Otherwise, the lasers decompose the target to so small clusters and ions that they can not recombine and reconstruct SiC crystalline lattices.

  14. Btk29A-mediated tyrosine phosphorylation of armadillo/β-catenin promotes ring canal growth in Drosophila oogenesis.

    PubMed

    Hamada-Kawaguchi, Noriko; Nishida, Yasuyoshi; Yamamoto, Daisuke

    2015-01-01

    Drosophila Btk29A is the ortholog of mammalian Btk, a Tec family nonreceptor tyrosine kinase whose deficit causes X-linked agammaglobulinemia in humans. The Btk29AficP mutation induces multiple abnormalities in oogenesis, including the growth arrest of ring canals, large intercellular bridges that allow the flow of cytoplasm carrying maternal products essential for embryonic development from the nurse cells to the oocyte during oogenesis. In this study, inactivation of Parcas, a negative regulator of Btk29A, was found to promote Btk29A accumulation on ring canals with a concomitant increase in the ring canal diameter, counteracting the Btk29AficP mutation. This mutation markedly reduced the accumulation of phosphotyrosine on ring canals and in the regions of cell-cell contact, where adhesion-supporting proteins such as DE-cadherin and β-catenin ortholog Armadillo (Arm) are located. Our previous in vitro and in vivo analyses revealed that Btk29A directly phosphorylates Arm, leading to its release from DE-cadherin. In the present experiments, immunohistological analysis revealed that phosphorylation at tyrosine 150 (Y150) and Y667 of Arm was diminished in Btk29AficP mutant ring canals. Overexpression of an Arm mutant with unphosphorylatable Y150 inhibited ring canal growth. Thus Btk29A-induced Y150 phosphorylation is necessary for the normal growth of ring canals. We suggest that the dissociation of tyrosine-phosphorylated Arm from DE-cadherin allows dynamic actin to reorganize, leading to ring canal expansion and cell shape changes during the course of oogenesis.

  15. Responses of tree-ring growth and crop yield to drought indices in the Shanxi province, North China.

    PubMed

    Sun, Junyan; Liu, Yu

    2014-09-01

    In this paper, we analyze the relationships among the tree-ring chronology, meteorological drought (precipitation), agricultural drought (Palmer Drought Severity Index PDSI), hydrological drought (runoff), and agricultural data in the Shanxi province of North China. Correlation analyses indicate that the tree-ring chronology is significantly correlated with all of the drought indices during the main growing season from March to July. Sign test analyses further indicate that the tree-ring chronology shows variation similar to that of the drought indices in both high and low frequencies. Comparisons of the years with narrow tree rings to the severe droughts reflected in all three indices from 1957 to 2008 reveal that the radial growth of the trees in the study region can accurately record the severe drought for which all three indices were in agreement (1972, 1999, 2000, and 2001). Comparisons with the dryness/wetness index indicate that tree-ring growth can properly record the severe droughts in the history. Correlation analyses among agricultural data, tree-ring chronology, and drought indices indicate that the per-unit yield of summer crops is relatively well correlated with the agricultural drought, as indicated by the PDSI. The PDSI is the climatic factor that significantly influences both tree growth and per-unit yield of summer crops in the study region. These results indicate that the PDSI and tree-ring chronology have the potential to be used to monitor and predict the yield of summer crops. Tree-ring chronology is an important tool for drought research and for wider applications in agricultural and hydrological research.

  16. [Paleoclimate of La Guajira, Colombia; by the growth rings of Capparis odoratissima (Capparidaceae)].

    PubMed

    Ramírez, Jorge Andrés; Ignacio del Valle, Jorge

    2011-09-01

    There is great concern about the effect of climate change in arid and subarid areas of the tropics. Climate change combined with other anthropogenic activities such as deforestation, fires and over-grazing can accelerate their degradation and, consequently, the increases in losses of biological and economic productivity. Climate models, both local and global, predict that rainfall in the arid Peninsula of La Guajira in the Colombian Caribbean would be reduced and temperature would be increased as a result of climate change. However, as there are only suitable climate records since 1972, it is not possible to verify if, indeed, this is happening. To try to verify the hypothesis of reducing rainfall and rising temperatures we developed a growth ring chronology of Capparis odoratissima in the Middle Peninsula of La Guajira with 17 trees and 45 series which attain 48 years back. We use standard dendrochronological methods that showed statistically significant linear relationship with local climatic variables such as air temperature, sea surface temperature (SST), annual precipitation and wind speed; we also reach to successful relationship of the chronology with global climatic variables as the indices SOI and MEI of the ENSO phenomenon. The transfer functions estimated with the time series (1955 and 2003) do not showed statistically significant trends, indicating that during this period of time the annual precipitation or temperatures have not changed. The annual nature of C. odoratissima growth rings, the possibility of cross-dated among the samples of this species, and the high correlation with local and global climatic variables indicate a high potential of this species for dendrochronological studies in this part of the American continent.

  17. Sep7 Is Essential to Modify Septin Ring Dynamics and Inhibit Cell Separation during Candida albicans Hyphal Growth

    PubMed Central

    González-Novo, Alberto; Correa-Bordes, Jaime; Labrador, Leticia; Sánchez, Miguel

    2008-01-01

    When Candida albicans yeast cells receive the appropriate stimulus, they switch to hyphal growth, characterized by continuous apical elongation and the inhibition of cell separation. The molecular basis of this inhibition is poorly known, despite its crucial importance for hyphal development. In C. albicans, septins are important for hypha formation and virulence. Here, we used fluorescence recovery after photobleaching analysis to characterize the dynamics of septin rings during yeast and hyphal growth. On hyphal induction, septin rings are converted to a hyphal-specific state, characterized by the presence of a frozen core formed by Sep7/Shs1, Cdc3 and Cdc12, whereas Cdc10 is highly dynamic and oscillates between the ring and the cytoplasm. Conversion of septin rings to the hyphal-specific state inhibits the translocation of Cdc14 phosphatase, which controls cell separation, to the hyphal septum. Modification of septin ring dynamics during hyphal growth is dependent on Sep7 and the hyphal-specific cyclin Hgc1, which partially controls Sep7 phosphorylation status and protein levels. Our results reveal a link between the cell cycle machinery and septin cytoskeleton dynamics, which inhibits cell separation in the filaments and is essential for hyphal morphogenesis. PMID:18234840

  18. Reconstruction of Pacific salmon abundance from riparian tree-ring growth.

    PubMed

    Drake, D C; Naiman, Robert J

    2007-07-01

    We use relationships between modern Pacific salmon (Oncorhynchus spp.) escapement (migrating adults counted at weirs or dams) and riparian tree-ring growth to reconstruct the abundance of stream-spawning salmon over 150-350 years. After examining nine sites, we produced reconstructions for five mid-order rivers and four salmon species over a large geographic range in the Pacific Northwest: chinook (O. tschwatcha) in the Umpqua River, Oregon, USA; sockeye (O. nerka) in Drinkwater Creek, British Columbia, Canada; pink (O. gorbuscha) in Sashin Creek, southeastern Alaska, USA; chum (O. keta) in Disappearance Creek, southeastern Alaska, USA; and pink and chum in the Kadashan River, southeastern Alaska, USA. We first derived stand-level, non-climatic growth chronologies from riparian trees using standard dendroecology methods and differencing. When the chronologies were compared to 18-55 years of adult salmon escapement we detected positive, significant correlations at five of the nine sites. Regression models relating escapement to tree-ring growth at the five sites were applied to the differenced chronologies to reconstruct salmon abundance. Each reconstruction contains unique patterns characteristic of the site and salmon species. Reconstructions were validated by comparison to local histories (e.g., construction of dams and salmon canneries) and regional fisheries data such as salmon landings and aerial surveys and the Pacific Decadal Oscillation climate index. The reconstructions capture lower-frequency cycles better than extremes and are most useful for determination and comparison of relative abundance, cycles, and the effects of interventions. Reconstructions show lower population cycle maxima in both Umpqua River chinook and Sashin Creek pink salmon in recent decades. The Drinkwater Creek reconstruction suggests that sockeye abundance since the mid-1990s has been 15-25% higher than at any time since 1850, while no long-term deviations from natural cycles are

  19. Flood Plain Aggradation Rates Based on Tree-Ring Growth-Suppression Dates

    NASA Astrophysics Data System (ADS)

    Friedman, J. M.

    2003-12-01

    When woody riparian plants are partially buried subsequent tree rings of the buried stems resemble those of roots. Annual rings in a buried stem are narrower and have larger vessels then those in unburied sections of the same stem. We have used this phenomenon to date flood plain sediments exposed in trenches, along two ephemeral streams in New Mexico (Rio Puerco and Chaco Wash) where the sediments are predominantly silt and very fine sand and the plants are predominantly tamarisk and willow. Cross dating down the stem allows dating of the first growth-season following burial by thick beds, and constrains the age of all stratigraphic units deposited since germination of the tree. We observed that the anatomical reaction to burial increases with bed thickness and cumulative deposition. Beds that are thicker than 30 cm can be dated to the year of the deposition event. Beds 10 to 30 cm thick can usually be dated to within several years. The period of deposition of multiple very thin beds can be constrained to the decade. Results can be improved by analyzing multiple stems from one tree and multiple trees linked together by the stratigraphy. Along our study streams, sites far from the channel tend to have moderate and relatively steady point-aggradation rates. Levees next to the channel tend to have the thickest deposits per flood and variable long-term rates, which can differ from the whole flood plain aggradation rates by several fold. Cross-sectionally averaged flood plain aggradation has been as large as a meter per decade along our study streams.

  20. Looking for age-related growth decline in natural forests: unexpected biomass patterns from tree rings and simulated mortality

    USGS Publications Warehouse

    Foster, Jane R.; D'Amato, Anthony W.; Bradford, John B.

    2014-01-01

    Forest biomass growth is almost universally assumed to peak early in stand development, near canopy closure, after which it will plateau or decline. The chronosequence and plot remeasurement approaches used to establish the decline pattern suffer from limitations and coarse temporal detail. We combined annual tree ring measurements and mortality models to address two questions: first, how do assumptions about tree growth and mortality influence reconstructions of biomass growth? Second, under what circumstances does biomass production follow the model that peaks early, then declines? We integrated three stochastic mortality models with a census tree-ring data set from eight temperate forest types to reconstruct stand-level biomass increments (in Minnesota, USA). We compared growth patterns among mortality models, forest types and stands. Timing of peak biomass growth varied significantly among mortality models, peaking 20–30 years earlier when mortality was random with respect to tree growth and size, than when mortality favored slow-growing individuals. Random or u-shaped mortality (highest in small or large trees) produced peak growth 25–30 % higher than the surviving tree sample alone. Growth trends for even-aged, monospecific Pinus banksiana or Acer saccharum forests were similar to the early peak and decline expectation. However, we observed continually increasing biomass growth in older, low-productivity forests of Quercus rubra, Fraxinus nigra, and Thuja occidentalis. Tree-ring reconstructions estimated annual changes in live biomass growth and identified more diverse development patterns than previous methods. These detailed, long-term patterns of biomass development are crucial for detecting recent growth responses to global change and modeling future forest dynamics.

  1. Looking for age-related growth decline in natural forests: unexpected biomass patterns from tree rings and simulated mortality.

    PubMed

    Foster, Jane R; D'Amato, Anthony W; Bradford, John B

    2014-05-01

    Forest biomass growth is almost universally assumed to peak early in stand development, near canopy closure, after which it will plateau or decline. The chronosequence and plot remeasurement approaches used to establish the decline pattern suffer from limitations and coarse temporal detail. We combined annual tree ring measurements and mortality models to address two questions: first, how do assumptions about tree growth and mortality influence reconstructions of biomass growth? Second, under what circumstances does biomass production follow the model that peaks early, then declines? We integrated three stochastic mortality models with a census tree-ring data set from eight temperate forest types to reconstruct stand-level biomass increments (in Minnesota, USA). We compared growth patterns among mortality models, forest types and stands. Timing of peak biomass growth varied significantly among mortality models, peaking 20-30 years earlier when mortality was random with respect to tree growth and size, than when mortality favored slow-growing individuals. Random or u-shaped mortality (highest in small or large trees) produced peak growth 25-30% higher than the surviving tree sample alone. Growth trends for even-aged, monospecific Pinus banksiana or Acer saccharum forests were similar to the early peak and decline expectation. However, we observed continually increasing biomass growth in older, low-productivity forests of Quercus rubra, Fraxinus nigra, and Thuja occidentalis. Tree-ring reconstructions estimated annual changes in live biomass growth and identified more diverse development patterns than previous methods. These detailed, long-term patterns of biomass development are crucial for detecting recent growth responses to global change and modeling future forest dynamics.

  2. Anatomical features that facilitate radial flow across growth rings and from xylem to cambium in Cryptomeria japonica

    PubMed Central

    Kitin, Peter; Fujii, Tomoyuki; Abe, Hisashi; Takata, Katsuhiko

    2009-01-01

    Background and Aims Although the lateral movement of water and gas in tree stems is an important issue for understanding tree physiology, as well as for the development of wood preservation technologies, little is known about the vascular pathways for radial flow. The aim of the current study was to understand the occurrence and the structure of anatomical features of sugi (Cryptomeria japonica) wood including the tracheid networks, and area fractions of intertracheary pits, tangential walls of ray cells and radial intercellular spaces that may be related to the radial permeability (conductivity) of the xylem. Methods Wood structure was investigated by light microscopy and scanning electron microscopy of traditional wood anatomical preparations and by a new method of exposed tangential faces of growth-ring boundaries. Key Results Radial wall pitting and radial grain in earlywood and tangential wall pitting in latewood provide a direct connection between subsequent tangential layers of tracheids. Bordered pit pairs occur frequently between earlywood and latewood tracheids on both sides of a growth-ring boundary. In the tangential face of the xylem at the interface with the cambium, the area fraction of intertracheary pit membranes is similar to that of rays (2·8 % and 2·9 %, respectively). The intercellular spaces of rays are continuous across growth-ring boundaries. In the samples, the mean cross-sectional area of individual radial intercellular spaces was 1·2 µm2 and their total volume was 0·06 % of that of the xylem and 2·07 % of the volume of rays. Conclusions A tracheid network can provide lateral apoplastic transport of substances in the secondary xylem of sugi. The intertracheid pits in growth-ring boundaries can be considered an important pathway, distinct from that of the rays, for transport of water across growth rings and from xylem to cambium. PMID:19258338

  3. The gravitational interaction between inclined, elliptical rings. [Uranus rings

    NASA Technical Reports Server (NTRS)

    Yoder, C. F.

    1982-01-01

    An expression for the potential for two elliptical, inclined rings is derived from a model in which the gravitational torque between two wide rings or within a ring of finite width can prevent differential precession caused by planetary oblateness. The model was proposed to explain the observed eccentricity and width variations of the Uranian epsilon ring. The stationary solutions and stability of this system are examined.

  4. RING1 and YY1 binding protein suppresses breast cancer growth and metastasis.

    PubMed

    Zhou, Hongyan; Li, Jie; Zhang, Zhanqiang; Ye, Runyi; Shao, Nan; Cheang, Tuckyun; Wang, Shenming

    2016-12-01

    Evidence suggests that RING1 and YY1 binding protein (RYBP) functions as a tumor suppressor. However, its role in breast cancer remains unclear. In the present study, the expression of RYBP was assessed in breast cancer patients and cell lines. Disease-free survival durations of breast cancer patients with high RYBP expression were determined based on the ATCG dataset. The effects of RYBP overexpression on cell growth, migration and invasive potency were also assessed. Nude mouse xenograft and lung metastasis models were also used to confirm the role of RYBP. The involvement of SRRM3 in RYBP-mediated breast cancer suppression was explored using SRRM3 siRNA. The potential relationship between RYBP, SRRM3, and REST-003 was examined by qPCR. The results showed that RYBP was downregulated in breast cancer patients and in several breast cancer cell lines. Breast cancer patients with high expression levels of RYBP displayed better disease-free survival. Overexpression of RYBP in MDA-MB-231 and SK-BR-3 cells significantly decreased cell proliferation, migration, and invasion ability, and increased the proportion of cells arrested in S-phase compared with the negative control cells. Additionally, upregulation of proliferation-related cell cycle proteins (cyclin A and cyclin B1) and E-cadherin, and downregulation of snail were observed in RYBP-overexpressing cells. Overexpression of RYBP reduced tumor volume and weight as well as metastatic foci in the lungs of nude mice. SRRM3 knockdown by siRNA, which is downregulated after RYBP overexpression, suppressed cell growth and metastasis in MDA-MB-231 and SK-BR-3 cells. Furthermore, qPCR analysis revealed that REST-003 ncRNA was downregulated in cells overexpressing RYBP and in SRRM3-inhibited cells. Moreover, cell invasion ability and growth were increased after SRRM3 upregulation in RYBP-overexpressing cells, but they were decreased following si-REST-003 transfection. In conclusion, overexpression of RYBP suppresses breast

  5. Increase in platinum group elements in Mexico City as revealed from growth rings of Taxodium mucronatum ten.

    PubMed

    Morton-Bermea, Ofelia; Beramendi-Orosco, Laura; Martínez-Reyes, Ángeles; Hernández-Álvarez, Elizabeth; González-Hernández, Galia

    2016-02-01

    Tree rings may be used as indicators of contamination events providing information on the chronology and the elemental composition of the contamination. In this framework, we report PGEs enrichment in growth rings of Taxodium mucronatum ten for trees growing in the central area of Mexico City as compared to trees growing in a non-urban environment. Concentrations of PGE were determined by ICP-MS analysis on microwave-digested tree rings. The element found in higher concentrations was Pd (1.13-87.98 μg kg(-1)), followed by Rh (0.28-36.81 μg kg(-1)) and Pt (0.106-7.21 μg kg(-1)). The concentration trends of PGEs in the tree-ring sequences from the urban area presented significant correlation values when comparing between trees (r between 0.618 and 0.98, P < 0.025) and between elements within individual trees (r between 0.76 and 0.994, P < 0.01). Furthermore, a clear increase was observed for rings after 1997, with enrichment of up to 60 times the mean concentration found for the sequence from the non-urban area and up to 40 times the mean concentration for the pre-1991 period in the urban trees. These results also demonstrate the feasibility of applying T. mucronatum ten to be used as a bioindicator of the increase in PGE in urban environments.

  6. Tree-ring evidence for the historical absence of cyclic larch budmoth outbreaks in the Tatra Mountains

    Treesearch

    Oliver Konter; Jan Esper; Andrew Liebhold; Tomas Kyncl; Lea Schneider; Elisabeth Düthorn; Ulf. Buntgen

    2015-01-01

    The absence of larch budmoth outbreaks and subsequent consequences on tree rings together with a distinct climate–growth relationship enhance the dendroclimatic potential of larch ring width data from the Tatra Mountains. Regular population oscillations are generally considered to arise from trophic interactions, though it is unclear how such cycles are...

  7. Does prism width from the shell prismatic layer have a random distribution?

    NASA Astrophysics Data System (ADS)

    Vancolen, Séverine; Verrecchia, Eric

    2008-10-01

    A study of the distribution of the prism width inside the prismatic layer of Unio tumidus (Philipsson 1788, Diss Hist-Nat, Berling, Lundæ) from Lake Neuchâtel, Switzerland, has been conducted in order to determine whether or not this distribution is random. Measurements of 954 to 1,343 prism widths (depending on shell sample) have been made using a scanning electron microscope in backscattered electron mode. A white noise test has been applied to the distribution of prism sizes (i.e. width). It shows that there is no temporal cycle that could potentially influence their formation and growth. These results suggest that prism widths are randomly distributed, and related neither to external rings nor to environmental constraints.

  8. Element concentrations in growth rings of trees near an abandoned wood-preserving plant site at Jackson, Tennessee

    USGS Publications Warehouse

    Yanosky, T.M.; Carmichael, J.K.

    1993-01-01

    Multielement analysis was performed on individual annual rings of trees growing at and near an abandoned wood-preserving plant site in Jackson, Tennessee, that operated from the early 1930's until 1981. Numerous organic compounds associated with the wood-preserving process have been detected in soils, ground water, and surface water within much of the site. Tree-ring investigations were conducted prior to investigations of ground water downgradient from the site to determine if trees preserved an areal and temporal record of contaminant movement into offsite areas. Increment cores were collected from trees on the abandoned plant site, in downgradient areas west and south of the site, and at two locations presumably unaffected by contamination from the site. Multielement analysis by proton-induced X-ray emission was performed on 5 to 15 individual growth rings from each of 34 trees that ranged in age from about 5 to 50 years. Concentrations of 16 elements were evaluated by analyzing average concentrations within the 1987, 1989, and 1990 rings of all trees; analyzing element-concentration trends along entire core radii; and analyzing element correlations between and among trees. Concentrations of some nutrients and trace metals were elevated in the outermost sapwood rings of some trees that grow south and southwest of the most contaminated part of the site; small trees on the main part of the site and larger trees to the west generally contained fewer rings with elevated concentrations, particularly of trace metals. Concentrations of several elements elevated in tree rings also were elevated in water samples collected from the reach of a stream that flows near the southwestern part of the site. Multielement analysis of each ring of a willow growing along the southern boundary of the site detected extremely large concentrations of chromium, nickel, and iron in rings that formed in 1986 and thereafter. Relative increases in the concentrations of these elements also

  9. Insensitivity of Tree-Ring Growth to Temperature and Precipitation Sharpens the Puzzle of Enhanced Pre-Eruption NDVI on Mt. Etna (Italy).

    PubMed

    Seiler, Ruedi; Kirchner, James W; Krusic, Paul J; Tognetti, Roberto; Houlié, Nicolas; Andronico, Daniele; Cullotta, Sebastiano; Egli, Markus; D'Arrigo, Rosanne; Cherubini, Paolo

    2017-01-01

    On Mt. Etna (Italy), an enhanced Normalized Difference in Vegetation Index (NDVI) signature was detected in the summers of 2001 and 2002 along a distinct line where, in November 2002, a flank eruption subsequently occurred. These observations suggest that pre-eruptive volcanic activity may have enhanced photosynthesis along the future eruptive fissure. If a direct relation between NDVI and future volcanic eruptions could be established, it would provide a straightforward and low-cost method for early detection of upcoming eruptions. However, it is unclear if, or to what extent, the observed enhancement of NDVI can be attributed to volcanic activity prior to the subsequent eruption. We consequently aimed at determining whether an increase in ambient temperature or additional water availability owing to the rise of magma and degassing of water vapour prior to the eruption could have increased photosynthesis of Mt. Etna's trees. Using dendro-climatic analyses we quantified the sensitivity of tree ring widths to temperature and precipitation at high elevation stands on Mt. Etna. Our findings suggest that tree growth at high elevation on Mt. Etna is weakly influenced by climate, and that neither an increase in water availability nor an increase in temperature induced by pre-eruptive activity is a plausible mechanism for enhanced photosynthesis before the 2002/2003 flank eruption. Our findings thus imply that other, yet unknown, factors must be sought as causes of the pre-eruption enhancement of NDVI on Mt. Etna.

  10. Insensitivity of Tree-Ring Growth to Temperature and Precipitation Sharpens the Puzzle of Enhanced Pre-Eruption NDVI on Mt. Etna (Italy)

    PubMed Central

    Krusic, Paul J.; Tognetti, Roberto; Houlié, Nicolas; Andronico, Daniele; Egli, Markus; D'Arrigo, Rosanne

    2017-01-01

    On Mt. Etna (Italy), an enhanced Normalized Difference in Vegetation Index (NDVI) signature was detected in the summers of 2001 and 2002 along a distinct line where, in November 2002, a flank eruption subsequently occurred. These observations suggest that pre-eruptive volcanic activity may have enhanced photosynthesis along the future eruptive fissure. If a direct relation between NDVI and future volcanic eruptions could be established, it would provide a straightforward and low-cost method for early detection of upcoming eruptions. However, it is unclear if, or to what extent, the observed enhancement of NDVI can be attributed to volcanic activity prior to the subsequent eruption. We consequently aimed at determining whether an increase in ambient temperature or additional water availability owing to the rise of magma and degassing of water vapour prior to the eruption could have increased photosynthesis of Mt. Etna's trees. Using dendro-climatic analyses we quantified the sensitivity of tree ring widths to temperature and precipitation at high elevation stands on Mt. Etna. Our findings suggest that tree growth at high elevation on Mt. Etna is weakly influenced by climate, and that neither an increase in water availability nor an increase in temperature induced by pre-eruptive activity is a plausible mechanism for enhanced photosynthesis before the 2002/2003 flank eruption. Our findings thus imply that other, yet unknown, factors must be sought as causes of the pre-eruption enhancement of NDVI on Mt. Etna. PMID:28099435

  11. No evidence for consistent long-term growth stimulation of 13 tropical tree species: results from tree-ring analysis.

    PubMed

    Groenendijk, Peter; van der Sleen, Peter; Vlam, Mart; Bunyavejchewin, Sarayudh; Bongers, Frans; Zuidema, Pieter A

    2015-10-01

    The important role of tropical forests in the global carbon cycle makes it imperative to assess changes in their carbon dynamics for accurate projections of future climate-vegetation feedbacks. Forest monitoring studies conducted over the past decades have found evidence for both increasing and decreasing growth rates of tropical forest trees. The limited duration of these studies restrained analyses to decadal scales, and it is still unclear whether growth changes occurred over longer time scales, as would be expected if CO2 -fertilization stimulated tree growth. Furthermore, studies have so far dealt with changes in biomass gain at forest-stand level, but insights into species-specific growth changes - that ultimately determine community-level responses - are lacking. Here, we analyse species-specific growth changes on a centennial scale, using growth data from tree-ring analysis for 13 tree species (~1300 trees), from three sites distributed across the tropics. We used an established (regional curve standardization) and a new (size-class isolation) growth-trend detection method and explicitly assessed the influence of biases on the trend detection. In addition, we assessed whether aggregated trends were present within and across study sites. We found evidence for decreasing growth rates over time for 8-10 species, whereas increases were noted for two species and one showed no trend. Additionally, we found evidence for weak aggregated growth decreases at the site in Thailand and when analysing all sites simultaneously. The observed growth reductions suggest deteriorating growth conditions, perhaps due to warming. However, other causes cannot be excluded, such as recovery from large-scale disturbances or changing forest dynamics. Our findings contrast growth patterns that would be expected if elevated CO2 would stimulate tree growth. These results suggest that commonly assumed growth increases of tropical forests may not occur, which could lead to erroneous

  12. Tree ring chronology indexes and reconstructions of precipitation in Central Iowa, USA

    SciTech Connect

    Blasing, T.J.; Duvick, D.N.

    1984-09-01

    Over sixty trees were sampled at each of the three Iowa sites; at least two cores were taken from most of the trees. The growth rings of each core were dated by calendar year, following standard procedures. Ring widths were measured to the nearest one-hundredth of a millimeter. Low-frequency variations resulting from tree age, changes in competitive status, and other nonclimatic factors were minimized by fitting a spline curve to the ring-width series and dividing each ring width by the value of the curve for the corresponding span. The average adjusted ring-width index for each year was computed from the indices of all cores at a site to obtain the chronology of ring-width indices (or tree ring chronologies) presented here. Based on the oldest tree samples, the initial years of the three chronologies in the study were 1635 at Pammel, 1654 at Duvick Back Woods, and 1663 at Ledges, Iowa. The sample sizes of the chronologies ranged from 6 to 16 cores by the year 1680 and increased steadily in each chronology after 1800. Indices are included for the three sites through 1981. A reconstruction of annual precipitation for central Iowa for the period 1860-1979 is based on these three chronologies.

  13. Population differentiation in tree-ring growth response of white fir (Abies concolor) to climate: Implications for predicting forest responses to climate change

    SciTech Connect

    Jensen, Deborah Bowne

    1993-01-01

    Forest succession models and correlative models have predicted 200--650 kilometer shifts in the geographic range of temperate forests and forest species as one response to global climate change. Few studies have investigated whether population differences may effect the response of forest species to climate change. This study examines differences in tree-ring growth, and in the phenotypic plasticity of tree-ring growth in 16-year old white fir, Abies concolor, from ten populations grown in four common gardens in the Sierra Nevada of California. For each population, tree-ring growth was modelled as a function of precipitation and degree-day sums. Tree-ring growth under three scenarios of doubled CO2 climates was estimated.

  14. Tree-ring growth of Scots pine, Common beech and Pedunculate oak under future climate in northeastern Germany

    NASA Astrophysics Data System (ADS)

    Jurasinski, Gerald; Scharnweber, Tobias; Schröder, Christian; Lennartz, Bernd; Bauwe, Andreas

    2017-04-01

    Tree growth depends, among other factors, largely on the prevailing climatic conditions. Therefore, tree growth patterns are to be expected under climate change. Here, we analyze the tree-ring growth response of three major European tree species to projected future climate across a climatic (mostly precipitation) gradient in northeastern Germany. We used monthly data for temperature, precipitation, and the standardized precipitation evapotranspiration index (SPEI) over multiple time scales (1, 3, 6, 12, and 24 months) to construct models of tree-ring growth for Scots pine (Pinus syl- vestris L.) at three pure stands, and for Common beech (Fagus sylvatica L.) and Pedunculate oak (Quercus robur L.) at three mature mixed stands. The regression models were derived using a two-step approach based on partial least squares regression (PLSR) to extract potentially well explaining variables followed by ordinary least squares regression (OLSR) to consolidate the models to the least number of variables while retaining high explanatory power. The stability of the models was tested with a comprehensive calibration-verification scheme. All models were successfully verified with R2s ranging from 0.21 for the western pine stand to 0.62 for the beech stand in the east. For growth prediction, climate data forecasted until 2100 by the regional climate model WETTREG2010 based on the A1B Intergovernmental Panel on Climate Change (IPCC) emission scenario was used. For beech and oak, growth rates will likely decrease until the end of the 21st century. For pine, modeled growth trends vary and range from a slight growth increase to a weak decrease in growth rates depending on the position along the climatic gradient. The climatic gradient across the study area will possibly affect the future growth of oak with larger growth reductions towards the drier east. For beech, site-specific adaptations seem to override the influence of the climatic gradient. We conclude that in Northeastern

  15. Analysis of tracheid development in suppressed-growth Ponderosa Pine using the FPL ring profiler

    Treesearch

    C. Tim Scott; David W. Vahey

    2012-01-01

    The Ring Profiler was developed to examine the cross-sectional morphology of wood tracheids in a 12.5-mm core sample. The instrument integrates a specially designed staging apparatus with an optical imaging system to obtain high-contrast, high-resolution images containing about 200-500 tracheids. These images are further enhanced and analyzed to extract tracheid cross-...

  16. Seasonal climate signals from multiple tree ring metrics: A case study of Pinus ponderosa in the upper Columbia River Basin

    NASA Astrophysics Data System (ADS)

    Dannenberg, Matthew P.; Wise, Erika K.

    2016-04-01

    Projected changes in the seasonality of hydroclimatic regimes are likely to have important implications for water resources and terrestrial ecosystems in the U.S. Pacific Northwest. The tree ring record, which has frequently been used to position recent changes in a longer-term context, typically relies on signals embedded in the total ring width of tree rings. Additional climatic inferences at a subannual temporal scale can be made using alternative tree ring metrics such as earlywood and latewood widths and the density of tree ring latewood. Here we examine seasonal precipitation and temperature signals embedded in total ring width, earlywood width, adjusted latewood width, and blue intensity chronologies from a network of six Pinus ponderosa sites in and surrounding the upper Columbia River Basin of the U.S. Pacific Northwest. We also evaluate the potential for combining multiple tree ring metrics together in reconstructions of past cool- and warm-season precipitation. The common signal among all metrics and sites is related to warm-season precipitation. Earlywood and latewood widths differ primarily in their sensitivity to conditions in the year prior to growth. Total and earlywood widths from the lowest elevation sites also reflect cool-season moisture. Effective correlation analyses and composite-plus-scale tests suggest that combining multiple tree ring metrics together may improve reconstructions of warm-season precipitation. For cool-season precipitation, total ring width alone explains more variance than any other individual metric or combination of metrics. The composite-plus-scale tests show that variance-scaled precipitation reconstructions in the upper Columbia River Basin may be asymmetric in their ability to capture extreme events.

  17. Understanding the growth rate patterns of ion Bernstein instabilities driven by ring-like proton velocity distributions

    NASA Astrophysics Data System (ADS)

    Min, Kyungguk; Liu, Kaijun

    2016-04-01

    Fast magnetosonic waves in Earth's inner magnetosphere, which have as their source ion Bernstein instabilities, are driven by hot proton velocity distributions (fp) with ∂fp(v⊥)/∂v⊥>0. Two typical types of distributions with such features are ring and shell velocity distributions. Both have been used in studies of ion Bernstein instabilities and fast magnetosonic waves, but the differences between instabilities driven by the two types of distributions have not been thoroughly addressed. The present study uses linear kinetic theory to examine and understand these differences. It is found that the growth rate pattern is primarily determined by the cyclotron resonance condition and the structure of the velocity distribution in gyroaveraged velocity space. For ring-driven Bernstein instabilities, as the parallel wave number (k∥) increases, the discrete unstable modes approximately follow the corresponding proton cyclotron harmonic frequencies while they become broader in frequency space. At sufficiently large k∥, the neighboring discrete modes merge into a continuum. In contrast, for shell-driven Bernstein instabilities, the curved geometry of the shell velocity distribution in gyroaveraged velocity space results in a complex alternating pattern of growth and damping rates in frequency and wave number space and confines the unstable Bernstein modes to relatively small k∥. In addition, when k∥ increases, the unstable modes are no longer limited to the proton cyclotron harmonic frequencies. The local growth rate peak near an exact harmonic at small k∥ bifurcates into two local peaks on both sides of the harmonic when k∥ becomes large.

  18. Stand structure and composition provide differential tree-ring growth signals in eastern U.S. forests

    NASA Astrophysics Data System (ADS)

    Alexander, M. R.; Rollinson, C.; Dye, A.; Pederson, N.; Moore, D. J.; Trouet, V.

    2016-12-01

    The assumption that a single dominant climatic factor synchronizes regional forest growth response is the foundation of annually resolved climate reconstructions. However, growth-limiting factors affect individual trees and in complex forests, such as those in the eastern U.S., these limitations may not be uniform across the entire stand. Forest structure and composition can influence climate growth responses and result in multiple growth signals recorded in the tree rings that may not be isolated using conventional techniques. To address this issue, we collected tree cores from five eastern U.S. forest stands that are influenced by large-scale climate factors as well as small-scale ecological pressures, such as competition between individuals. We used generalized additive mixed models to form multivariate models of tree growth at the site-, species-, and canopy class-levels that account for the simultaneous influences that climate and size factors exert on growth through time. Species- and canopy position-specific models adhere more closely to observations (R2 = 0.73 and R2 = 0.71, respectively) than the site-level model (R2 = 0.60). Across all models, sensitivities to temperature and size are more dynamic through time than precipitation sensitivity. Size is the primary limiting factor as trees establish during the juvenile phase and temperature and precipitation limit growth as stands mature and individuals emerge into the canopy. We see that the species response to climate is relatively well conserved across all sites, but the dynamic nature of the size effect unique to each site alters the expressed limiting factor. We find that sub-canopy individuals show an opposite response to temperature than that the dominant and intermediate strata, likely due to the microclimate conditions created by a stratified canopy. Tree growth is thus limited by a combination of climatological and forest structural factors (i.e. canopy class) and growth limitations vary through

  19. Growth and assembly of cobalt oxide nanoparticle rings at liquid nanodroplets with solid junction.

    PubMed

    Zhou, Yilong; Powers, Alexander S; Zhang, Xiaowei; Xu, Tao; Bustillo, Karen; Sun, Litao; Zheng, Haimei

    2017-09-13

    Using liquid cell TEM, we imaged the formation of CoO nanoparticle rings. Nanoparticles nucleated and grew tracing the perimeter of droplets sitting on the SiNx solid substrate, and finally formed necklace-like rings. By tracking single nanoparticle trajectories during the ring formation and an estimation of the forces between droplets and nanoparticles using a simplified model, we found the junction of liquid nanodroplets with a solid substrate is the attractive site for CoO nanoparticles. Coalescing droplets were capable of pushing nanoparticles to the perimeter of the new droplet and nanoparticles on top of the droplets rolled off toward the perimeter. We propose that the curved surface morphology of the droplets created a force gradient that contributed to the assembly of nanoparticles at the droplet perimeter. Revealing the dynamics of nanoparticle movements and the interactions of nanoparticles with the liquid nanodroplet provides insights on developing novel self-assembly strategies for building precisely defined nanostructures on solid substrates.

  20. [Responses of Chinese pine tree ring in Shenyang suburb (Fu Mausoleum) to global temperature fluctuation].

    PubMed

    Chen, Zhen-Ju; He, Xing-Yuan; Chen, Wei; Sun, Yu; Zhang, Chun-Tao; Fu, Yin-Dong; Tian, Wei; Liu, Tie-Hong

    2007-09-01

    In this paper, the correlations between the variations of Chinese pine (Pinus tabulaeformis Carr.) tree ring width in Shenyang suburb (Fu Mausoleum) and the local temperature variables, Global Surface Air Temperature Anomaly (GSATA) from 1880 to 2004, Global Land-Ocean Temperature (GLOTI) from 1880 to 2004 and North Hemisphere Temperature Anomaly (NHTA) from 1880 to 2004 were studied. Some close correlations were detected, and the local temperature variables, GSATA, GLOTI and NHTA had some similar influences on the Chinese pine tree ring width. The air temperature in last winter (December and January) and in spring (April and May) affected the growth of Chinese pine significantly (P < 0.05). There existed a 3-8-year periodicity of the variation of Chinese pine tree ring width and the GSATA, GLOTI and NHTA, and the 19.3-year and 23.2-year quasi-periodicity of the variation of Chinese pine tree ring width corresponded with the 20.8-year quasi-periodicity of GSATA, GLOTI and NHTA. This study suggested that the Chinese pine tree ring width in Shenyang Fu Mausoleum had positive correlations with global-scale temperature fluctuation, and the temperature increase in the past had a positive effect on the Chinese pine growth.

  1. Critical Role of the Ubiquitin Ligase Activity of UHRF1, a Nuclear RING Finger Protein, in Tumor Cell GrowthD⃞

    PubMed Central

    Jenkins, Yonchu; Markovtsov, Vadim; Lang, Wayne; Sharma, Poonam; Pearsall, Denise; Warner, Justin; Franci, Christian; Huang, Betty; Huang, Jianing; Yam, George C.; Vistan, Joseph P.; Pali, Erlina; Vialard, Jorge; Janicot, Michel; Lorens, James B.; Payan, Donald G.; Hitoshi, Yasumichi

    2005-01-01

    Early cellular events associated with tumorigenesis often include loss of cell cycle checkpoints or alteration in growth signaling pathways. Identification of novel genes involved in cellular proliferation may lead to new classes of cancer therapeutics. By screening a tetracycline-inducible cDNA library in A549 cells for genes that interfere with proliferation, we have identified a fragment of UHRF1 (ubiquitin-like protein containing PHD and RING domains 1), a nuclear RING finger protein, that acts as a dominant negative effector of cell growth. Reduction of UHRF1 levels using an UHRF1-specific shRNA decreased growth rates in several tumor cell lines. In addition, treatment of A549 cells with agents that activated different cell cycle checkpoints resulted in down-regulation of UHRF1. The primary sequence of UHRF1 contains a PHD and a RING motif, both of which are structural hallmarks of ubiquitin E3 ligases. We have confirmed using an in vitro autoubiquitination assay that UHRF1 displays RING-dependent E3 ligase activity. Overexpression of a GFP-fused UHRF1 RING mutant that lacks ligase activity sensitizes cells to treatment with various chemotherapeutics. Taken together, our results suggest a general requirement for UHRF1 in tumor cell proliferation and implicate the RING domain of UHRF1 as a functional determinant of growth regulation. PMID:16195352

  2. Transformation rules and degradation of CAHs by Fentonlike oxidation in growth ring of water distribution network-A review

    NASA Astrophysics Data System (ADS)

    Zhong, D.; Ma, W. C.; Jiang, X. Q.; Yuan, Y. X.; Yuan, Y.; Wang, Z. Q.; Fang, T. T.; Huang, W. Y.

    2017-08-01

    Chlorinated hydrocarbons are widely used as organic solvent and chemical raw materials. After treatment, water polluted with trichloroethylene (TCE)/tetrachloroethylene (PCE) can reach the water quality requirements, while water with trace amounts of TCE/PCE is still harmful to humans, which will cause cancers. Water distribution network is an extremely complicated system, in which adsorption, desorption, flocculation, movement, transformation and reduction will occur, leading to changes of TCE/PCE concentrations and products. Therefore, it is important to investigate the transformation rules of TCE/PCE in water distribution network. What’s more, growth-ring, including drinking water pipes deposits, can act as catalysts in Fenton-like reagent (H2O2). This review summarizes the status of transformation rules of CAHs in water distribution network. It also evaluates the effectiveness and fruit of CAHs degradation by Fenton-like reagent based on growth-ring. This review is important in solving the potential safety problems caused by TCE/PCE in water distribution network.

  3. A Void Growth Failure Criterion Applied to Dynamically and Statically Loaded Thin Rings.

    DTIC Science & Technology

    1980-06-01

    schematic diagram of this system is shown. A small gas laser (Spectra Physics 122) provides the required intense parallel beam of light. This beam was...LU "O e (3.24) Z LU 0 zz Using the Equations (3.21) to (3.23) in Equation (3.19), we get (Lke + a0 IeY it - FaeU)ieZ = ( FLue + Fa UyeU - CyIeU + (FLU...of a small collimated beam passing between the ring and a fixci knife edge positioned perpendi- cular to the specimen. The light intensity variation is

  4. Planetary Rings

    NASA Astrophysics Data System (ADS)

    Esposito, Larry

    2014-03-01

    Preface: a personal view of planetary rings; 1. Introduction: the allure of the ringed planets; 2. Studies of planetary rings 1610-2013; 3. Diversity of planetary rings; 4. Individual ring particles and their collisions; 5. Large-scale ring evolution; 6. Moons confine and sculpt rings; 7. Explaining ring phenomena; 8. N-body simulations; 9. Stochastic models; 10. Age and evolution of rings; 11. Saturn's mysterious F ring; 12. Uranus' rings and moons; 13. Neptune's partial rings; 14. Jupiter's ring-moon system after Galileo and New Horizons; 15. Ring photometry; 16. Dusty rings; 17. Concluding remarks; Afterword; Glossary; References; Index.

  5. Missing rings in Pinus halepensis – the missing link to relate the tree-ring record to extreme climatic events

    Treesearch

    Klemen Novak; Martin de Luis; Miguel A. Saz; Luis A. Longares; Roberto Serrano-Notivoli; Josep Raventos; Katarina Cufar; Jozica Gricar; Alfredo Di Filippo; Gianluca Piovesan; Cyrille B.K. Rathgeber; Andreas Papadopoulos; Kevin T. Smith

    2016-01-01

    Climate predictions for the Mediterranean Basin include increased temperatures, decreased precipitation, and increased frequency of extreme climatic events (ECE). These conditions are associated with decreased tree growth and increased vulnerability to pests and diseases. The anatomy of tree rings responds to these environmental conditions. Quantitatively, the width of...

  6. [Anatomic characterization of growth-rings in 80 potential tree species for dendrocronological studies in the Central Forest, Perú].

    PubMed

    Beltrán Gutiérrez, Lizandro Adal; Valencia Ramos, Gina Mariela

    2013-09-01

    The knowledge about the existence of annual tree rings in tropical trees, which was already found at the beginning of the last century, was ignored by many scientists for a long time. Wood samples of 80 tree species from seven different sites belonging to Satipo and Chanchamayo provinces in Central Forest, Perú. Wood slices were taken at 1.30 m height, following the Peruvian Technical Norms (NTP) 251-008, COPANT norms 30:1-019 and IAWA (1989). Results showed that 24 of the 80 tree species analyzed showed a potential for dendrocronological studies, 25 had problems for growth-rings analysis, and 31 did not have potential. The problems most frequently found were: barely visible or irregular ring growth, parenchyma bands and multiseriate rays difficult to be identified in rings growth. The "T" Student test showed that the significant variation in vessel and fiber diameters between growth zones (Early-wood and late-wood) of species with potential for dendrocronology, do have a periodic cells production, so is possible to suggest the annual formation of each growth-ring. However, those species without potential to dendrocronology may be influenced by of a lot of factors, such as biotic and abiotic conditions of environment, as well as the genetic aspect of each species.

  7. Relationship between the growth of the ring current and the interplanetary quantity. [solar wind energy-magnetospheric coupling parameter correlation with substorm AE index

    NASA Technical Reports Server (NTRS)

    Akasofu, S.-I.

    1979-01-01

    Akasofu (1979) has reported that the interplanetary parameter epsilon correlates reasonably well with the magnetospheric substorm index AE; in the first approximation, epsilon represents the solar wind coupled to the magnetosphere. The correlation between the interplanetary parameter, the auroral electrojet index and the ring current index is examined for three magnetic storms. It is shown that when the interplanetary parameter exceeds the amount that can be dissipated by the ionosphere in terms of the Joule heat production, the excess energy is absorbed by the ring current belt, producing an abnormal growth of the ring current index.

  8. Microbial growth on pall rings: a problem when upgrading biogas with the water-wash absorption technique.

    PubMed

    Tynell, Asa; Börjesson, Gunnar; Persson, Margareta

    2007-01-01

    Biogas is upgraded using an absorption with water-wash technique by 11 of a total of 14 upgrading plants in Sweden. However, problems with microbial growth on the pall rings in the absorption column, and in one case in the desorption column, have a negative impact on the upgrading of raw gas to vehicle gas. Five of the nine biogas plants studied here have experienced problems with microbial growth. The objectives of this study were to identify such microbial growth and to determine possible factors for its control, in order to provide recommendations for process management. A questionnaire was sent out and visits were made to the upgrading plants to collect information about the upgrading process. Phospholipid fatty acid (PLFA) analysis was performed to determine microbial biomass and community structure in samples from four upgrading plants. In samples from two of the plants, methane-oxidizing bacteria (type I methanotrophs) were indicated, while samples from one of the other plants showed biomarkers indicating actinomycetes. Factors affecting development of microbial growth were found to be water quality and the pH and temperature of the process water. Plants that used wastewater in the upgrading process experienced far more problems than those using clean water of drinking quality.

  9. Tree-ring stable isotope and growth impacts of climate variability: future implications for prairie-forest ecotones

    NASA Astrophysics Data System (ADS)

    Reed, Alexis S.; Billings, Sharon A.

    2010-05-01

    Shifts in prairie-forest ecotones are expected with forecasted global climate change. Understanding how co-occurring tree species respond to environmental variability may help in understanding species responses and potential retraction of tree species under future climate conditions. Contrasting growth-climate relationships derived from tree-rings among co-occurring Quercus macrocarpa, a predominant tree species along the North American prairie-forest ecotone, and Q. rubra, a species generally found in more mesic conditions, suggests a constant growth-climate relationship throughout the life of the tree. For example, no significant difference (P> 0.05) was found between residuals from regression of tree-ring basal area increments and Palmer Drought Severity Index (PDSI) in early or later years of either species, as derived from increment cores. These findings contrast with recent evidence of declines in drought sensitivity in Q. macrocarpa as this species ages, which may be linked to increased atmospheric carbon dioxide levels, and emphasize the need for further understanding of prairie-forest ecotone dynamics. Utilization of δ13C data from α-cellulose will provide further insight into the changing water-use and carbon dynamics in response to climate variability. Used in conjunction with growth-climate relationships, δ13C data may also assist in predicting future drought sensitivity and forest retraction in trees in prairie-forest ecotones. Continued sensitivity to drought regardless of the age of a tree remains an important concern in predicting future species ranges and prairie-forest species composition in the future.

  10. Plasma deposited rider rings for hot displacer

    DOEpatents

    Kroebig, Helmut L.

    1976-01-01

    A hot cylinder for a cryogenic refrigerator having two plasma spray deposited rider rings of a corrosion and abrasion resistant material provided in the rider ring grooves, wherein the rider rings are machined to the desired diameter and width after deposition. The rider rings have gas flow flats machined on their outer surface.

  11. Emittance growth in heavy ion rings due to effects of space charge and dispersion

    SciTech Connect

    Barnard, J.J., LLNL

    1998-06-03

    We review the derivation of moment equations which include the effects of space charge and dispersion in bends first presented in ref [1]. These equations generalize the familiar envelope equations to include the dispersive effects of bends. We review the application of these equations to the calculation of the change in emittance resulting from a sharp transition from a straight section to a bend section, using an energy conservation constraint. Comparisons of detailed 2D and 3D simulations of intense beams in rings using the WARP code (refs [2,3]) are made with results obtained from the moment equations. We also compare the analysis carried out in ref [1], to more recent analyses, refs [4,5]. We further examine self-consistent distributions of beams in bends and discuss the relevance of these distributions to the moment equation formulation.

  12. Crystal growth mechanisms in miarolitic cavities in the Lake George ring complex and vicinity, Colorado

    USGS Publications Warehouse

    Kile, D.E.; Eberl, D.D.

    1999-01-01

    The Crystal Peak area of the Pikes Peak batholith, near Lake George in central Colorado, is world-renowned for its crystals of amazonite (the blue-green variety of microcline) and smoky quartz. Such crystals, collected from individual miarolitic pegmatites, have a remakably small variation in crystal size within each pegmatite, and the shapes of plots of their crystal size distributions (CSDs) are invariably lognormal or close to lognormal in all cases. These observations are explained by a crystal growth mechanism that was governed initially by surface-controlled kinetics, during which crystals tended to grow larger in proportion to their size, thereby establishing lognormal CSDs. Surface-controlled growth was followed by longer periods of supply controlled growth, during which growth rate was predominantly size-independent, consequently preserving the lognormal shapes of the CSDs and the small size variation. The change from surface- to supply controlled growth kinetics may have resulted from an increasing demand for nutrients that exceeded diffusion limitations of the system. The proposed model for crystal growth in this locality appears to be common in the geologic record, and can be used with other information, such as isotopic data, to deduce physico-chemical conditions during crystal formation.

  13. Twisted mannitol crystals establish homologous growth mechanisms for high-polymer and small-molecule ring-banded spherulites.

    PubMed

    Shtukenberg, Alexander G; Cui, Xiaoyan; Freudenthal, John; Gunn, Erica; Camp, Eric; Kahr, Bart

    2012-04-11

    D-Mannitol belongs to a large and growing family of crystals with helical morphologies (Yu, L. J. Am. Chem. Soc.2003, 125, 6380). Two polymorphs of D-mannitol, α and δ, when grown in the presence of additives such as poly(vinylpyrrolidone) (PVP) or D-sorbitol, form ring-banded spherulites composed of handed helical fibrils, where the helix axes correspond to the radial growth directions. The two polymorphs form helices with opposite senses in the presence of PVP but the same sense in the presence of D-sorbitol. The characteristic dimensions of the fibrils, including thickness, aspect ratio, and pitch, were determined by scanning probe and electron microscopies. These values must form the basis of any theory that presupposes what forces give rise to crystal twisting, a problem that has been broached but unsettled in the literature of polymer crystallization. The interdependence of the rhythmic variations of both linear and circular birefringence, as determined by Mueller matrix microscopy, informs the cooperative organization of mannitol fibers. The microstructure of mannitol ring-banded spherulites compares favorably to that of high polymers and is evaluated within the context of current theories of crystal twisting.

  14. miR-762 promotes porcine immature Sertoli cell growth via the ring finger protein 4 (RNF4) gene

    PubMed Central

    Ma, Changping; Song, Huibin; Yu, Lei; Guan, Kaifeng; Hu, Pandi; Li, Yang; Xia, Xuanyan; Li, Jialian; Jiang, Siwen; Li, Fenge

    2016-01-01

    A growing number of reports have revealed that microRNAs (miRNAs) play critical roles in spermatogenesis. Our previous study showed that miR-762 is differentially expressed in immature and mature testes of Large White boars. Our present data shows that miR-762 directly binds the 3′ untranslated region (3′UTR) of ring finger protein 4 (RNF4) and down-regulates RNF4 expression. A single nucleotide polymorphism (SNP) in the RNF4 3′UTR that is significantly associated with porcine sperm quality traits leads to a change in the miR-762 binding ability. Moreover, miR-762 promotes the proliferation of and inhibits apoptosis in porcine immature Sertoli cells, partly by accelerating DNA damage repair and by reducing androgen receptor (AR) expression. Taken together, these findings suggest that miR-762 may play a role in pig spermatogenesis by regulating immature Sertoli cell growth. PMID:27596571

  15. Acclimatization process of tofu wastewater on hybrid upflow anaerobic sludge blanket reactor using polyvinyl chloride rings as a growth medium

    NASA Astrophysics Data System (ADS)

    Yanqoritha, Nyimas; Turmuzi, Muhammad; Derlini

    2017-05-01

    The appropriate process to resolve sewage contamination which have a high organic using anaerobic technology. Hybrid Upflow Anaerobic Sludge Blanket reactor is one of the anaerobic process which consists of a suspended growth media and attached growth media. The reactor has the ability to work at high load rate, sludge produced easily settles, high biomass and the separation of gas, solid and liquid excelent. The purpose of research is to study the acclimatization process in the reactor of Hybrid Upflow Anaerobic Sludge Blanket using a polyvinl chloride ring as the attached growth medium. Reactor of Hybrid Upflow Anaerobic Sludge Blanket use a working volume of 8.6 L. The operation consisting of 3 L suspended reactor and 5.6 L attached reactor. Acclimatization is conducted by providing the substrate from the smallest concentration of COD up to a concentration that will be processed. During the 50th day, acclimatization process assumed the bacteria begin to work, indicated by the dissolved COD and VSS decrease and biogas production. Due to the wastewater containing the high of protein in consequence operational parameters should be controlled and some precautions should be taken to prevent process partially or totally inhibited.

  16. Planetary Rings

    NASA Astrophysics Data System (ADS)

    Esposito, Larry W.

    2011-07-01

    Preface; 1. Introduction: the allure of ringed planets; 2. Studies of planetary rings 1610-2004; 3. Diversity of planetary rings; 4. Individual ring particles and their collisions; 5. Large-scale ring evolution; 6. Moons confine and sculpt rings; 7. Explaining ring phenomena; 8. N-Body simulations; 9. Stochastic models; 10. Age and evolution of rings; 11. Saturn's mysterious F ring; 12. Neptune's partial rings; 13. Jupiter's ring-moon system after Galileo; 14. Ring photometry; 15. Dusty rings; 16. Cassini observations; 17. Summary: the big questions; Glossary; References; Index.

  17. Tree-ring based history of climate and disease in western Oregon forests

    EPA Science Inventory

    Annual tree-ring width data are often used to make inferences of past climate and the spatiotemporal climate-growth relationships. However, the climatic signal may be confounded with non-climatic signals such as disease or pest disturbances at unknown times in the past. Signal e...

  18. Tree-ring based history of climate and disease in western Oregon forests

    EPA Science Inventory

    Annual tree-ring width data are often used to make inferences of past climate and the spatiotemporal climate-growth relationships. However, the climatic signal may be confounded with non-climatic signals such as disease or pest disturbances at unknown times in the past. Signal e...

  19. Tree-ring stable isotopes record the impact of a foliar fungal pathogen on CO(2) assimilation and growth in Douglas-fir.

    PubMed

    Saffell, Brandy J; Meinzer, Frederick C; Voelker, Steven L; Shaw, David C; Brooks, J Renée; Lachenbruch, Barbara; McKay, Jennifer

    2014-07-01

    Swiss needle cast (SNC) is a fungal disease of Douglas-fir (Pseudotsuga menziesii) that has recently become prevalent in coastal areas of the Pacific Northwest. We used growth measurements and stable isotopes of carbon and oxygen in tree-rings of Douglas-fir and a non-susceptible reference species (western hemlock, Tsuga heterophylla) to evaluate their use as proxies for variation in past SNC infection, particularly in relation to potential explanatory climate factors. We sampled trees from an Oregon site where a fungicide trial took place from 1996 to 2000, which enabled the comparison of stable isotope values between trees with and without disease. Carbon stable isotope discrimination (Δ(13)C) of treated Douglas-fir tree-rings was greater than that of untreated Douglas-fir tree-rings during the fungicide treatment period. Both annual growth and tree-ring Δ(13)C increased with treatment such that treated Douglas-fir had values similar to co-occurring western hemlock during the treatment period. There was no difference in the tree-ring oxygen stable isotope ratio between treated and untreated Douglas-fir. Tree-ring Δ(13)C of diseased Douglas-fir was negatively correlated with relative humidity during the two previous summers, consistent with increased leaf colonization by SNC under high humidity conditions that leads to greater disease severity in following years.

  20. Growth Patterns of Signet Ring Cell Carcinoma of the Stomach for Endoscopic Resection.

    PubMed

    Kim, Hyunki; Kim, Jie-Hyun; Lee, Yong Chan; Kim, Hoguen; Youn, Young Hoon; Park, Hyojin; Choi, Seung Ho; Noh, Sung Hoon; Gotoda, Takuji

    2015-11-23

    It is difficult to precisely detect the lateral margin during endoscopic submucosal dissection (ESD) for signet ring cell carcinoma (SRC) because SRC often expands to lateral direction through the lamina propria. Thus, the aim of this study was to classify the intramucosal spreading patterns of SRC and to analyze the patients' clinicopathological findings according to the spreading patterns. The intramucosal spreading patterns of SRC were classified as expansive or infiltrative types. A total of 100 surgical and 42 ESD specimens were reviewed. In the surgical specimens, the proportions of expansive and infiltrative types were 44% and 56%, respectively. The infiltrative type was more commonly associated with old age, atrophy, and intestinal metaplasia in surrounding mucosa and the absence of Helicobacter pylori compared with the expansive type. In ESD specimens, the proportions of expansive and infiltrative types were each 50%. When lateral margin-positive lesions were compared with -negative lesions, larger size, residual lesion, and the lack of a neutrophil infiltration were more significantly associated with lateral margin-positive lesions. All cases with residual tumors in lateral margin-positive lesions were classified as the infiltrative type. SRC surrounded with atrophy and/or intestinal metaplasia often spreads subepithelially in the margin. This finding may suggest that a larger safety margin is necessary in this type during ESD.

  1. Record of the Solar Activity and of Other Geophysical Phenomenons in Tree Ring

    NASA Astrophysics Data System (ADS)

    Rigozo, Nivaor Rodolfo

    1999-01-01

    Tree ring studies are usually used to determine or verify climatic factors which prevail in a given place or region and may cause tree ring width variations. Few studies are dedicated to the geophysical phenomena which may underlie these tree ring width variations. In order to look for periodicities which may be associated to the solar activity and/or to other geophysical phenomena which may influence tree ring growth, a new interactive image analysis method to measure tree ring width was developed and is presented here. This method makes use of a computer and a high resolution flatbed scanner; a program was also developed in Interactive Data Language (IDL 5.0) to study ring digitized images and transform them into time series. The main advantage of this method is the tree ring image interactive analysis without needing complex and high cost instrumentation. Thirty-nine samples were collected: 12 from Concordia - S. C., 9 from Canela - R. S., 14 from Sao Francisco de Paula - R. S., one from Nova Petropolis - R. S., 2 from Sao Martinho da Serra - R. S. e one from Chile. Fit functions are applied to ring width time series to obtain the best long time range trend (growth rate of every tree) curves and are eliminated through a standardization process that gives the tree ring index time series from which is performed spectral analysis by maximum entropy method and iterative regression. The results obtained show periodicities close to 11 yr, 22 yr Hale solar cycles and 5.5 yr for all sampling locations 52 yr and Gleissberg cycles for Concordia - S. C. and Chile samples. El Nino events were also observed with periods around 4 e 7 yr.

  2. Maintenance of muscle mass and load-induced growth in Muscle RING Finger 1 null mice with age.

    PubMed

    Hwee, Darren T; Baehr, Leslie M; Philp, Andrew; Baar, Keith; Bodine, Sue C

    2014-02-01

    Age-related loss of muscle mass occurs to varying degrees in all individuals and has a detrimental effect on morbidity and mortality. Muscle RING Finger 1 (MuRF1), a muscle-specific E3 ubiquitin ligase, is believed to mediate muscle atrophy through the ubiquitin proteasome system (UPS). Deletion of MuRF1 (KO) in mice attenuates the loss of muscle mass following denervation, disuse, and glucocorticoid treatment; however, its role in age-related muscle loss is unknown. In this study, skeletal muscle from male wild-type (WT) and MuRF1 KO mice was studied up to the age of 24 months. Muscle mass and fiber cross-sectional area decreased significantly with age in WT, but not in KO mice. In aged WT muscle, significant decreases in proteasome activities, especially 20S and 26S β5 (20-40% decrease), were measured and were associated with significant increases in the maladaptive endoplasmic reticulum (ER) stress marker, CHOP. Conversely, in aged MuRF1 KO mice, 20S or 26S β5 proteasome activity was maintained or decreased to a lesser extent than in WT mice, and no increase in CHOP expression was measured. Examination of the growth response of older (18 months) mice to functional overload revealed that old WT mice had significantly less growth relative to young mice (1.37- vs. 1.83-fold), whereas old MuRF1 KO mice had a normal growth response (1.74- vs. 1.90-fold). These data collectively suggest that with age, MuRF1 plays an important role in the control of skeletal muscle mass and growth capacity through the regulation of cellular stress. © 2013 the Anatomical Society and John Wiley & Sons Ltd.

  3. A comparison of chronologies from tree rings

    Treesearch

    Kurt H. Riitters

    1990-01-01

    Forty-five-year ring width index chronologies were estimated by five mean-value functions applied to 183 ring width series from four similar sites. The effects of autocorrelation on the comparisons among mean-value functions were explored by fitting box-Jenkins models to individual-tree index services prior to pooling (prewhitening), and to the pooled chronologies...

  4. Tree-ring stable isotopes record the impact of a foliar fungal pathogen on CO2 assimilation and growth in Douglas-fir

    EPA Science Inventory

    Swiss needle cast (SNC) is a fungal disease of Douglas-fir (Pseudotsuga menziesii) that has recently become prevalent in coastal areas of the Pacific Northwest. We used growth measurements and stable isotopes of carbon and oxygen in tree-rings of Douglas-fir and a non-susceptible...

  5. Tree-ring stable isotopes record the impact of a foliar fungal pathogen on CO2 assimilation and growth in Douglas-fir

    EPA Science Inventory

    Swiss needle cast (SNC) is a fungal disease of Douglas-fir (Pseudotsuga menziesii) that has recently become prevalent in coastal areas of the Pacific Northwest. We used growth measurements and stable isotopes of carbon and oxygen in tree-rings of Douglas-fir and a non-susceptible...

  6. Distribution of trace element in Japanese red coral Paracorallium japonicum by μ-XRF and sulfur speciation by XANES: Linkage between trace element distribution and growth ring formation

    NASA Astrophysics Data System (ADS)

    Trong Nguyen, Luan; Rahman, Mohammad Azizur; Maki, Teruya; Tamenori, Yusuke; Yoshimura, Toshihiro; Suzuki, Atsushi; Iwasaki, Nozomu; Hasegawa, Hiroshi

    2014-02-01

    This study investigated the distribution of magnesium (Mg), phosphorus (P), sulfur (S) and strontium (Sr) using micro X-ray fluorescence (μ-XRF), and the speciation of S using X-ray absorption near edge spectroscopy (XANES) along the annual growth rings in the skeleton of Japanese red coral Paracorallium japonicum. The Mg, P and S distribution in μ-XRF mapping images correspond to the dark and light bands along the annual growth rings in microscopic images of the coral skeleton. The μ-XRF mapping data showed a positive correlation (r = 0.6) between P and S distribution in the coral skeleton. A contrasting distribution pattern of S and Mg along the axial skeleton of P. japonicum indicates a weak negative correlation (r = -0.2) between these two elements. The distribution pattern of S, P and Mg in the axial skeleton of P. japonicum reveals linkage between the trace element distribution and the formation of dark/light bands along the annual growth rings. Sulfur and P were distributed in the organic matrix rich dark bands, while Mg was distributed in the light bands of the annual growth rings. XANES analysis showed that inorganic sulfate is the major species of S in the skeleton of P. japonicum with a ratio of 1:20 for organic and inorganic sulfate.

  7. Effect of growth ring orientation and placement of earlywood and latewood on MOE and MOR of very-small clear Douglas-fir beams.

    Treesearch

    Amy T. Grotta; Robert J. Leichti; Barbara L. Gartner; G.R. Johnson

    2005-01-01

    ASTM standard sizes for bending tests (either 50 x 50 mm or 25 x 25 mm in cross-section) are not always suitable for research purposes that characterize smaller sections of wood. Moreover, the ASTM standards specify loading the sample on the longitudinal-tangential surface. If specimens are small enough, then the effects of both growth-ring orientation and whether...

  8. Diatomic predissociation line widths

    NASA Technical Reports Server (NTRS)

    Child, M. S.

    1973-01-01

    Predissociation by rotation and curve crossing in diatomic molecules is discussed. The pattern of predissociation line widths is seen as providing a highly sensitive yardstick for the determination of unknown potential curves. In addition, the computation of such a pattern for given potential curves is considered a matter of routine, unless the predissociation happens to occur from an adiabatic potential curve. Analytic formulas are used to provide physical insight into the details of the predissociation pattern, to the extent that a direct inversion procedure is developed for determination of the repulsive potential curves for Type 1 predissociations.

  9. Long range correlations in tree ring chronologies of the USA: Variation within and across species

    NASA Astrophysics Data System (ADS)

    Bowers, M. C.; Gao, J. B.; Tung, W. W.

    2013-02-01

    Abstract Tree <span class="hlt">ring</span> <span class="hlt">width</span> data are among the best proxies for reconstructing past temperature and precipitation records. The discovery of fractal scaling and long-memory in meteorological and hydrological signals motivates us to investigate such properties in tree <span class="hlt">ring</span> chronologies. Detrended fluctuation analysis and adaptive fractal analysis are utilized to estimate the Hurst parameter values of 697 tree <span class="hlt">ring</span> chronologies from the continental United States. We find significant differences in the Hurst parameter values across the 10 species studied in the work. The long-range scaling relations found here suggest that the behavior of tree <span class="hlt">ring</span> <span class="hlt">growth</span> observed in a short calibration period may be similar to the general behavior of tree <span class="hlt">ring</span> <span class="hlt">growth</span> in a much longer period, and therefore, the limited calibration period may be more useful than originally thought. The variations of the long-range correlations within and across species may be further explored in future to better reconstruct paleoclimatic records.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012NIMPB.284....6M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012NIMPB.284....6M"><span>Effect of selective area <span class="hlt">growth</span> mask <span class="hlt">width</span> on multi-quantum-well electroabsorption modulated lasers investigated by synchrotron radiation X-ray microprobe</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mino, Lorenzo; Agostino, Angelo; Codato, Simone; Martinez-Criado, Gema; Lamberti, Carlo</p> <p>2012-08-01</p> <p>High performance optoelectronic devices require monolithic integration of different functions at chip level. This is the case of multi-quantum well (MQW) electroabsorption modulated laser (EML), employed in long-distance, high-frequency optical fiber communication applications, which is realized exploiting the selective area <span class="hlt">growth</span> (SAG) technique. Optimization of the <span class="hlt">growth</span> parameters is carried out by empirical approaches since a direct characterization of the MQW is not possible with laboratory X-ray sources, owing to the micrometer-variation of composition and thickness inherent to the SAG technique. In this work we combined micrometer-resolved photoluminescence with synchrotron radiation micrometer-resolved X-ray fluorescence to study the effect of different SAG masks on the electronic properties and chemical composition of the SAG MQW EML device.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/6043193','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/6043193"><span>Studies and calculations of transverse emittance <span class="hlt">growth</span> in high-energy proton storage <span class="hlt">rings</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Mane, S.R.; Jackson, G.</p> <p>1989-03-01</p> <p>In the operation of proton-antiproton colliders, an important goal is to maximize the integrated luminosity. During such operations in the Fermilab Tevatron, the transverse beam emittances were observed to grow unexpectedly quickly, thus causing a serious reduction of the luminosity. We have studied this phenomenon experimentally and theoretically. A formula for the emittance <span class="hlt">growth</span> rate, due to random dipole kicks, is derived. In the experiment, RF phase noise of known amplitude was deliberately injected into the Tevatron to kick the beam randomly, via dispersion at the RF cavities. Theory and experiment are found to agree reasonably well. We also briefly discuss the problem of quadrupole kicks. 14 refs., 2 figs., 3 tabs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4611665','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4611665"><span>Drosophila E-cadherin is required for the maintenance of <span class="hlt">ring</span> canals anchoring to mechanically withstand tissue <span class="hlt">growth</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Loyer, Nicolas; Kolotuev, Irina; Pinot, Mathieu; Le Borgne, Roland</p> <p>2015-01-01</p> <p>Intercellular bridges called “<span class="hlt">ring</span> canals” (RCs) resulting from incomplete cytokinesis play an essential role in intercellular communication in somatic and germinal tissues. During Drosophila oogenesis, RCs connect the maturing oocyte to nurse cells supporting its <span class="hlt">growth</span>. Despite numerous genetic screens aimed at identifying genes involved in RC biogenesis and maturation, how RCs anchor to the plasma membrane (PM) throughout development remains unexplained. In this study, we report that the clathrin adaptor protein 1 (AP-1) complex, although dispensable for the biogenesis of RCs, is required for the maintenance of the anchorage of RCs to the PM to withstand the increased membrane tension associated with the exponential tissue <span class="hlt">growth</span> at the onset of vitellogenesis. Here we unravel the mechanisms by which AP-1 enables the maintenance of RCs’ anchoring to the PM during size expansion. We show that AP-1 regulates the localization of the intercellular adhesion molecule E-cadherin and that loss of AP-1 causes the disappearance of the E-cadherin–containing adhesive clusters surrounding the RCs. E-cadherin itself is shown to be required for the maintenance of the RCs’ anchorage, a function previously unrecognized because of functional compensation by N-cadherin. Scanning block-face EM combined with transmission EM analyses reveals the presence of interdigitated, actin- and Moesin-positive, microvilli-like structures wrapping the RCs. Thus, by modulating E-cadherin trafficking, we show that the sustained E-cadherin–dependent adhesion organizes the microvilli meshwork and ensures the proper attachment of RCs to the PM, thereby counteracting the increasing membrane tension induced by exponential tissue <span class="hlt">growth</span>. PMID:26424451</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26424451','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26424451"><span>Drosophila E-cadherin is required for the maintenance of <span class="hlt">ring</span> canals anchoring to mechanically withstand tissue <span class="hlt">growth</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Loyer, Nicolas; Kolotuev, Irina; Pinot, Mathieu; Le Borgne, Roland</p> <p>2015-10-13</p> <p>Intercellular bridges called "<span class="hlt">ring</span> canals" (RCs) resulting from incomplete cytokinesis play an essential role in intercellular communication in somatic and germinal tissues. During Drosophila oogenesis, RCs connect the maturing oocyte to nurse cells supporting its <span class="hlt">growth</span>. Despite numerous genetic screens aimed at identifying genes involved in RC biogenesis and maturation, how RCs anchor to the plasma membrane (PM) throughout development remains unexplained. In this study, we report that the clathrin adaptor protein 1 (AP-1) complex, although dispensable for the biogenesis of RCs, is required for the maintenance of the anchorage of RCs to the PM to withstand the increased membrane tension associated with the exponential tissue <span class="hlt">growth</span> at the onset of vitellogenesis. Here we unravel the mechanisms by which AP-1 enables the maintenance of RCs' anchoring to the PM during size expansion. We show that AP-1 regulates the localization of the intercellular adhesion molecule E-cadherin and that loss of AP-1 causes the disappearance of the E-cadherin-containing adhesive clusters surrounding the RCs. E-cadherin itself is shown to be required for the maintenance of the RCs' anchorage, a function previously unrecognized because of functional compensation by N-cadherin. Scanning block-face EM combined with transmission EM analyses reveals the presence of interdigitated, actin- and Moesin-positive, microvilli-like structures wrapping the RCs. Thus, by modulating E-cadherin trafficking, we show that the sustained E-cadherin-dependent adhesion organizes the microvilli meshwork and ensures the proper attachment of RCs to the PM, thereby counteracting the increasing membrane tension induced by exponential tissue <span class="hlt">growth</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4469605','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4469605"><span>Relation between Red Cell Distribution <span class="hlt">Width</span> and Fibroblast <span class="hlt">Growth</span> Factor 23 Cleaving in Patients with Chronic Kidney Disease and Heart Failure</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>van Breda, Fenna; Emans, Mireille E.; van der Putten, Karien; Braam, Branko; van Ittersum, Frans J.; Kraaijenhagen, Rob J.; de Borst, Martin H.; Vervloet, Marc; Gaillard, Carlo A. J. M.</p> <p>2015-01-01</p> <p>Objective In chronic kidney disease (CKD), both anemia and deregulated phosphate metabolism are common and predictive of adverse outcome. Previous studies suggest that iron status influences phosphate metabolism by modulating proteolytic cleavage of FGF23 into C-terminal fragments. Red cell distribution <span class="hlt">width</span> (RDW) was recently identified as a strong prognostic determinant for cardiovascular morbidity and mortality, independently of iron status. We assessed whether RDW is associated with FGF23 cleaving in CKD patients with heart failure. Materials and Methods The associations between RDW and either intact FGF23 (iFGF23), C-terminal FGF23 (cFGF23, reflecting iFGF23 and C-terminal fragments together) and the iFGF23/cFGF23 ratio were analyzed in 52 patients with CKD (eGFR 34,9 ± 13.9 ml/min/1.73m2) and chronic heart failure (CHF). Associations between RDW and FGF23 forms were studied by linear regression analysis adjusted for parameters of renal function, iron metabolism, phosphate metabolism and inflammation. Results Median cFGF23 levels were 197.5 [110–408.5] RU/ml, median iFGF23 levels were 107.3 [65.1–162.2] pg/ml and median FGF23 ratio was 0.80 [0.37–0.86]. Mean RDW was 14.1 ± 1.2%. cFGF23 and RDW were associated (β = 1.63x10-3, P <0.001), whereas iFGF23 and RDW were not (β = -1.38x10-3, P = 0.336). The iFGF23/cFGF23 ratio was inversely associated with RDW. The difference between cFGF23 and iFGF23 (cFGF23- iFGF23) was positively associated with RDW (β = 1.74x10-3, P< 0.001). The association between cFGF23 and RDW persisted upon multivariable linear regression analysis, adjusted for parameters of renal function, phosphate metabolism, iron metabolism and inflammation (β = 0.97x10-3, P = 0.047). Conclusion RDW is associated with cFGF23 but not with iFGF23 levels in patients with CKD and CHF. This suggests a connection between RDW and FGF23 catabolism, independent of iron status and inflammation. Future studies are needed to unravel underlying mechanisms</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011IAUS..271..102W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011IAUS..271..102W"><span>On the formation of <span class="hlt">ring</span> galaxies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wu, Yu-Ting; Jiang, Ing-Guey</p> <p>2011-08-01</p> <p>The formation scenario of <span class="hlt">ring</span> galaxies is addressed in this paper. We focus on the P-type <span class="hlt">ring</span> galaxies presented in Madore, Nelson & Petrillo (2009), particularly on the axis-symmetric ones. Our simulations show that a <span class="hlt">ring</span> can form through the collision of disc and dwarf galaxies, and the locations, <span class="hlt">widths</span>, and density contrasts of the <span class="hlt">ring</span> are well determined. We find that a <span class="hlt">ring</span> galaxy such as AM 2302-322 can be produced by this collision scenario.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3850941','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3850941"><span>Fine-scale spatiotemporal influences of salmon on <span class="hlt">growth</span> and nitrogen signatures of Sitka spruce tree <span class="hlt">rings</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2013-01-01</p> <p>Background The marine-terrestrial transfer of salmon (Oncorhynchus spp.) provides a substantial pulse of nutrients to receiving ecosystems along the Pacific coast of North America and has been shown to enhance productivity and isotopic signatures of conifers and other riparian vegetation. An explicitly spatial, within-watershed investigation of the influence of salmon on conifers has never been previously investigated. In a small salmon-bearing watershed in Haida Gwaii, Canada, the transfer and distributional pattern of salmon carcasses into the riparian zone by black bears provided a spatial basis for investigating the influence of salmon on Sitka spruce tree <span class="hlt">ring</span> <span class="hlt">growth</span> and nitrogen isotopic signatures (δ15N) across a gradient of salmon carcass densities in relation to salmon escapement. Results Annual <span class="hlt">growth</span> was found to be highest in the high salmon carcass zone and δ15N signatures closely tracked the known distribution of salmon carcasses at distances into the forest and upstream. Tree diameter demonstrated a positive relationship with δ15N signatures for trees with and without salmon carcass influence. Using an information theoretics approach with general linear mixed models (GLMMs), we show that salmon abundance, mean annual temperature and the interaction terms salmon abundance*temperature and salmon abundance*distance into the forest best predict tree <span class="hlt">growth</span>. In addition, spatial variables (distance into forest and upstream) and their interaction are the strongest predictors of δ15N signatures. However patterns observed in individual trees, particularly those at increased distance into the forest, suggest positive relationships with historical salmon abundance. Conclusions Using a replicated spatial sampling design across a sharp gradient in salmon nutrient loading, our study provides clear evidence that the temporal pattern in an allochthonous nutrient source and an interaction with temperature and spatial location influences conifer <span class="hlt">growth</span>. Although</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..DFDA33003K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..DFDA33003K"><span>Coffee-<span class="hlt">ring</span> effect beyond the dilute limit</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kim, Jin Young; Ryu, Seul-A.; Kim, Hyungdae; Kim, Joon Heon; Park, Jung Su; Park, Yong Seok; Oh, Jeong Su; Weon, Byung Mook</p> <p>2015-11-01</p> <p>The coffee-<span class="hlt">ring</span> effect, which is a natural generation of outward capillary flows inside drying coffee drops, is valid at the dilute limit of initial solute concentrations. If the solute is not dilute, the <span class="hlt">ring</span> deposit is forced to have a non-zero <span class="hlt">width</span>; higher initial concentration leads to a wider <span class="hlt">ring</span>. Here we study the coffee-<span class="hlt">ring</span> effect in the dense limit by demonstrating differences with various initial coffee concentrations from 0.1% to 60%. The coffee drops with high initial concentrations of real coffee particles show interesting evaporation dynamics: dense coffee drops tend to evaporate slowly. This result is different from the classic coffee-<span class="hlt">ring</span> effect in the dilute limit. We suppose that the slow evaporation of dense coffee drops is associated with the <span class="hlt">ring</span> <span class="hlt">growth</span> dynamics. The coffee-<span class="hlt">ring</span> effect becomes more significant in modern technologies such as self-assembly of nanoparticles, ink-jet printing, painting and ceramics. The complexity in evaporation dynamics of colloidal fluids would be able to be understood by expanding the coffee-<span class="hlt">ring</span> effects in the dilute as well as the dense limits.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/971341','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/971341"><span>Wavelength-tunable optical <span class="hlt">ring</span> resonators</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Watts, Michael R.; Trotter, Douglas C.; Young, Ralph W.; Nielson, Gregory N.</p> <p>2009-11-10</p> <p>Optical <span class="hlt">ring</span> resonator devices are disclosed that can be used for optical filtering, modulation or switching, or for use as photodetectors or sensors. These devices can be formed as microdisk <span class="hlt">ring</span> resonators, or as open-<span class="hlt">ring</span> resonators with an optical waveguide having a <span class="hlt">width</span> that varies adiabatically. Electrical and mechanical connections to the open-<span class="hlt">ring</span> resonators are made near a maximum <span class="hlt">width</span> of the optical waveguide to minimize losses and thereby provide a high resonator Q. The <span class="hlt">ring</span> resonators can be tuned using an integral electrical heater, or an integral semiconductor junction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1021901','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1021901"><span>Wavelength-tunable optical <span class="hlt">ring</span> resonators</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Watts, Michael R.; Trotter, Douglas C.; Young, Ralph W.; Nielson, Gregory N.</p> <p>2011-07-19</p> <p>Optical <span class="hlt">ring</span> resonator devices are disclosed that can be used for optical filtering, modulation or switching, or for use as photodetectors or sensors. These devices can be formed as microdisk <span class="hlt">ring</span> resonators, or as open-<span class="hlt">ring</span> resonators with an optical waveguide having a <span class="hlt">width</span> that varies adiabatically. Electrical and mechanical connections to the open-<span class="hlt">ring</span> resonators are made near a maximum <span class="hlt">width</span> of the optical waveguide to minimize losses and thereby provide a high resonator Q. The <span class="hlt">ring</span> resonators can be tuned using an integral electrical heater, or an integral semiconductor junction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.B11C0449K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.B11C0449K"><span>Model-based analysis on the relationship between production and tree-<span class="hlt">ring</span> <span class="hlt">growth</span> in Japanese conifer-hardwood mixed forests</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Koide, D.; Ito, A.</p> <p>2015-12-01</p> <p>Forest productivity is a basic and important component of terrestrial material flow and its importance increases according to recent climate warming and the increase in atmospheric-CO2 concentrations. Forest productivity study progresses through measurement by eddy-covariance data from flux tower and prediction by terrestrial ecosystem models. However, flux tower observation has spatiotemporal bias and limitation. On the other hand, tree-<span class="hlt">ring</span> data have a close connection with forest ecosystem productivity. Compared to flux tower observation, we can collect tree-<span class="hlt">ring</span> data from a larger number of sites and longer time scales. Comparisons between tree-<span class="hlt">ring</span> observation and model-estimated productivity is important to reveal underlying mechanisms of forest ecosystem productivity and <span class="hlt">growth</span> in wide spatiotemporal scale. This study aimed at revealing the relationship between temporal changes in tree-<span class="hlt">ring</span> data and estimated forest ecosystem productivity in Japanese conifer-hardwood mixed forest. We also addressed climatic bias in the relationship by comparing between sites at different climatic conditions. Tree-<span class="hlt">ring</span> data of Sakhalin spruce (Picea glehnii) were obtained from the International Tree <span class="hlt">Ring</span> Data Bank. Six sites on the Hokkaido island (northern island of Japan) were selected for the present analysis. The Vegetation Integrated SImulator for Trace gasses (VISIT) model was validated by comparing with carbon flux data from Asia flux network sites. Past climatic parameters were obtained from ERA-20C reanalysis data from the European Center for Medium-range Weather Forecasts. Correlation between basal area increment and net ecosystem productivity was highest in the coldest site but this correlation weakened in warmer sites. This result implies that long-term <span class="hlt">growth</span> trend was mainly restricted by cold stress associated with productivity reduction in colder sites but this factor is less important and other factors exert influence in warmer sites.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=256514&keyword=decomposition+AND+process&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=89980681&CFTOKEN=76383336','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=256514&keyword=decomposition+AND+process&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=89980681&CFTOKEN=76383336"><span>Statistical methodologies for tree-<span class="hlt">ring</span> research to understand the climate-<span class="hlt">growth</span> relationships over time and space</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>The International Tree-<span class="hlt">Ring</span> Database is a valuable resource for studying climate change and its effects on terrestrial ecosystems over time and space. We examine the statistical methods in current use in dendroclimatology and dendroecology to process the tree-<span class="hlt">ring</span> data and make ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=256514&keyword=database+AND+statistical&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=256514&keyword=database+AND+statistical&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span>Statistical methodologies for tree-<span class="hlt">ring</span> research to understand the climate-<span class="hlt">growth</span> relationships over time and space</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>The International Tree-<span class="hlt">Ring</span> Database is a valuable resource for studying climate change and its effects on terrestrial ecosystems over time and space. We examine the statistical methods in current use in dendroclimatology and dendroecology to process the tree-<span class="hlt">ring</span> data and make ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/5179339','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/5179339"><span><span class="hlt">Width</span> of nonlinear resonance</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ohnuma, S.</p> <p>1984-03-01</p> <p>Two approximations are made, one essential and the other not so essential but convenient to keep the analytical treatment manageable: (1) Only one nonlinear resonance is considered at a time so that the treatment is best suited when the tune is close to one resonance only. To improve this approximation, one must go to the next order which involves a canonical transformation of dynamical variables. Analytical treatment of more than one resonance is not possible for general cases. (2) In the formalism using the action-angle variables, the Hamiltonian can have terms which are independent of the angle variables. These terms are called phase-independent terms or shear terms. The tune is then a function of the oscillation amplitudes. In the lowest-order treatment, the (4N)-pole components but not the (4N + 2)-pole components contribute to this dependence. In deriving the resonance <span class="hlt">width</span> analytically, one ignores these terms in the Hamiltonian for the sake of simplicity. If these are retained, one needs at least three extra parameters and the analytical treatment becomes rather unwieldy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014NatCo...5E3836S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014NatCo...5E3836S"><span>Arctic tree <span class="hlt">rings</span> as recorders of variations in light availability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stine, A. R.; Huybers, P.</p> <p>2014-05-01</p> <p>Annual <span class="hlt">growth</span> <span class="hlt">ring</span> variations in Arctic trees are often used to reconstruct surface temperature. In general, however, the <span class="hlt">growth</span> of Arctic vegetation is limited both by temperature and light availability, suggesting that variations in atmospheric transmissivity may also influence tree-<span class="hlt">ring</span> characteristics. Here we show that Arctic tree-<span class="hlt">ring</span> density is sensitive to changes in light availability across two distinct phenomena: explosive volcanic eruptions (P<0.01) and the recent epoch of global dimming (P<0.01). In each case, the greatest response is found in the most light-limited regions of the Arctic. Essentially no late 20th century decline in tree-<span class="hlt">ring</span> density relative to temperature is seen in the least light-limited regions of the Arctic. Consistent results follow from analysis of tree-<span class="hlt">ring</span> <span class="hlt">width</span> and from individually analysing each of seven tree species. Light availability thus appears an important control, opening the possibility for using tree <span class="hlt">rings</span> to reconstruct historical changes in surface light intensity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24805143','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24805143"><span>Arctic tree <span class="hlt">rings</span> as recorders of variations in light availability.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Stine, A R; Huybers, P</p> <p>2014-05-07</p> <p>Annual <span class="hlt">growth</span> <span class="hlt">ring</span> variations in Arctic trees are often used to reconstruct surface temperature. In general, however, the <span class="hlt">growth</span> of Arctic vegetation is limited both by temperature and light availability, suggesting that variations in atmospheric transmissivity may also influence tree-<span class="hlt">ring</span> characteristics. Here we show that Arctic tree-<span class="hlt">ring</span> density is sensitive to changes in light availability across two distinct phenomena: explosive volcanic eruptions (P<0.01) and the recent epoch of global dimming (P<0.01). In each case, the greatest response is found in the most light-limited regions of the Arctic. Essentially no late 20th century decline in tree-<span class="hlt">ring</span> density relative to temperature is seen in the least light-limited regions of the Arctic. Consistent results follow from analysis of tree-<span class="hlt">ring</span> <span class="hlt">width</span> and from individually analysing each of seven tree species. Light availability thus appears an important control, opening the possibility for using tree <span class="hlt">rings</span> to reconstruct historical changes in surface light intensity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4024743','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4024743"><span>Arctic tree <span class="hlt">rings</span> as recorders of variations in light availability</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Stine, A. R.; Huybers, P.</p> <p>2014-01-01</p> <p>Annual <span class="hlt">growth</span> <span class="hlt">ring</span> variations in Arctic trees are often used to reconstruct surface temperature. In general, however, the <span class="hlt">growth</span> of Arctic vegetation is limited both by temperature and light availability, suggesting that variations in atmospheric transmissivity may also influence tree-<span class="hlt">ring</span> characteristics. Here we show that Arctic tree-<span class="hlt">ring</span> density is sensitive to changes in light availability across two distinct phenomena: explosive volcanic eruptions (P<0.01) and the recent epoch of global dimming (P<0.01). In each case, the greatest response is found in the most light-limited regions of the Arctic. Essentially no late 20th century decline in tree-<span class="hlt">ring</span> density relative to temperature is seen in the least light-limited regions of the Arctic. Consistent results follow from analysis of tree-<span class="hlt">ring</span> <span class="hlt">width</span> and from individually analysing each of seven tree species. Light availability thus appears an important control, opening the possibility for using tree <span class="hlt">rings</span> to reconstruct historical changes in surface light intensity. PMID:24805143</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..1413742S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..1413742S"><span>iTREE: Long-term variability of tree <span class="hlt">growth</span> in a changing environment - identifying physiological mechanisms using stable C and O isotopes in tree <span class="hlt">rings</span>.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Siegwolf, R. T. W.; Buchmann, N.; Frank, D.; Joos, F.; Kahmen, A.; Treydte, K.; Leuenberger, M.; Saurer, M.</p> <p>2012-04-01</p> <p>Trees play are a critical role in the carbon cycle - their photosynthetic assimilation is one of the largest terrestrial carbon fluxes and their standing biomass represents the largest carbon pool of the terrestrial biosphere. Understanding how tree physiology and <span class="hlt">growth</span> respond to long-term environmental change is pivotal to predict the magnitude and direction of the terrestrial carbon sink. iTREE is an interdisciplinary research framework to capitalize on synergies among leading dendroclimatologists, plant physiologists, isotope specialists, and global carbon cycle modelers with the objectives of reducing uncertainties related to tree/forest <span class="hlt">growth</span> in the context of changing natural environments. Cross-cutting themes in our project are tree <span class="hlt">rings</span>, stable isotopes, and mechanistic modelling. We will (i) establish a European network of tree-<span class="hlt">ring</span> based isotope time-series to retrodict interannual to long-term tree physiological changes, (ii) conduct laboratory and field experiments to adapt a mechanistic isotope model to derive plant physiological variables from tree-<span class="hlt">ring</span> isotopes, (iii) implement this model into a dynamic global vegetation model, and perform subsequent model-data validation exercises to refine model representation of plant physiological processes and (iv) attribute long-term variation in tree <span class="hlt">growth</span> to plant physiological and environmental drivers, and identify how our refined knowledge revises predictions of the coupled carbon-cycle climate system. We will contribute to i) advanced quantifications of long-term variation in tree <span class="hlt">growth</span> across Central Europe, ii) novel long-term information on key physiological processes that underlie variations in tree <span class="hlt">growth</span>, and iii) improved carbon cycle models that can be employed to revise predictions of the coupled carbon-cycle climate system. Hence iTREE will significantly contribute towards a seamless understanding of the responses of terrestrial ecosystems to long-term environmental change, and ultimately</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014RaPC...95..346G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014RaPC...95..346G"><span>Biomonitoring of environmental pollution using <span class="hlt">growth</span> tree <span class="hlt">rings</span> of Tipuana tipu: Quantification by synchrotron radiation total reflection X-ray fluorescence</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Geraldo, S. M.; Canteras, F. B.; Moreira, S.</p> <p>2014-02-01</p> <p>Currently, many studies use the bioindicators to qualitatively and/or quantitatively measure pollution. The analyses of tree <span class="hlt">growth</span> <span class="hlt">rings</span> represent one such bioindicator as changes in the environment are often recorded as impressions in the wood. The main objective of the present study is to examine the <span class="hlt">growth</span> <span class="hlt">rings</span> of Tipuana tipu - a member of the Leguminosae family that is native to Argentina and Bolivia and was introduced in Brazil as an ornamental plant - for potentially toxic elements. T. tipu is one of the most common trees in the urban landscape of Sao Paulo city and would provide an accurate reflection of environment changes. Tree <span class="hlt">ring</span> samples previously dated using Synchrotron Radiation Total Reflection X-ray Fluorescence were collected from strategic locations in Sao Paulo. These locations include Piracicaba (SP) that has little access and small flow traffic and the campus of the University of São Paulo. Some trace elements present concentrations higher than considered as normal in some periods. In São Paulo city, samples collected from the campus of University of São Paulo (Butantã), showed the highest toxicity, with concentrations above the tolerable limit for the elements: Cr, Cu, and Pb. For the samples collected in Piracicaba city, one sample presented highest concentrations for the majority of the elements when compared to the other four samples collected at the same place, exceeding the toxicity limits for: Cr, Ni, Cu, and Pb.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/914299','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/914299"><span>High Variability of the Metal Content of Tree <span class="hlt">Growth</span> <span class="hlt">Rings</span> as Measured by Synchrotron Micro X-ray Fluorescence Spectrometry</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Martin,R.; Naftel, S.; Macfie, S.; Jones, K.; Feng, H.; Trembley, C.</p> <p>2006-01-01</p> <p>Synchrotron radiation analysis was used to investigate the metal content of tree <span class="hlt">rings</span> collected from paper birch, Betula papyrifera Marsh, on transects downwind from two metal smelters (nickel and copper). Individual trees reflected changes in <span class="hlt">ring</span> metal content with time, which may be presumed to represent changes in local metal bioavailability. However, between-tree variations were large and no statistically significant differences in metal content as a function of time were found within or between sites. Although concentrations of both total and exchangeable copper and nickel in the soil increased with proximity to the respective smelter, this pattern was reflected only in the nickel content of <span class="hlt">rings</span> near the nickel smelter; copper content did not vary with distance from either smelter. The sites did differ with respect to lead, manganese and zinc content of the <span class="hlt">rings</span>, which may be related to pH. In conclusion, the variability between trees at each site suggests that dendroanalysis is a poor method for evaluating metal exposure at a large (site) scale. Tree <span class="hlt">ring</span> metal content may be used to evaluate the metal uptake by individual trees but metal mobility in the stem makes it difficult to establish a reliable chronology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/EJ1054944.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/EJ1054944.pdf"><span>The <span class="hlt">Width</span> of a Proof</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Hanna, Gila</p> <p>2014-01-01</p> <p>This paper's aim is to discuss the concept of <span class="hlt">width</span> of a proof put forward by Timothy Gowers. It explains what this concept means and attempts to show how it relates to other concepts discussed in the existing literature on proof and proving. It also explores how the concept of <span class="hlt">width</span> of a proof might be used productively in the mathematics…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/753092','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/753092"><span>Phase <span class="hlt">width</span> reduction project summary</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Clark, D.J.; Xie, Z.Q.; McMahan, M. A.</p> <p>1999-11-01</p> <p>The purpose of the phase <span class="hlt">width</span> reduction project, 1993--96, was to reduce the phase <span class="hlt">width</span> of the 88-Inch Cyclotron beam on target from 5--10 ns to 1--2 ns for certain experiments, such as Gammasphere, which use time-of-flight identification. Since reducing the phase <span class="hlt">width</span> also reduces beam intensity, tuning should be done to also optimize the transmission. The Multi-turn Collimator slits in the cyclotron center region were used to collimate the early turns radially, thus reducing the phase <span class="hlt">width</span> from about 5 ns to 1--2 ns FWHM for a Gammasphere beam. The effect of the slits on phase <span class="hlt">width</span> was verified with a Fast Faraday Cup and with particle and gamma-ray detectors in the external beamline.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JDE...263.3460Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JDE...263.3460Z"><span>Homoclinic finger-<span class="hlt">rings</span> in RN</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhu, Changrong; Zhang, Weinian</p> <p>2017-09-01</p> <p>In this paper we investigate bifurcations of a degenerate homoclinic loop in RN. We prove that a homoclinic finger-<span class="hlt">ring</span>, an invariant manifold of a definite dimension textured with homoclinic orbits, arises from the degenerate homoclinic orbit. The size of the homoclinic finger-<span class="hlt">ring</span> is decided by not only its dimension of manifold but also its <span class="hlt">width</span>. For the rise of homoclinic finger-<span class="hlt">rings</span> of different dimensions we give conditions, which are proved to form bifurcation manifolds in the parameter space. We further estimate the <span class="hlt">width</span> for the homoclinic finger-<span class="hlt">ring</span> and give a method to compute the bifurcation manifolds approximately.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23455430','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23455430"><span>Effects of Agaricus lilaceps fairy <span class="hlt">rings</span> on soil aggregation and microbial community structure in relation to <span class="hlt">growth</span> stimulation of western wheatgrass (Pascopyrum smithii) in Eastern Montana rangeland.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Caesar-Tonthat, The Can; Espeland, Erin; Caesar, Anthony J; Sainju, Upendra M; Lartey, Robert T; Gaskin, John F</p> <p>2013-07-01</p> <p>Stimulation of plant productivity caused by Agaricus fairy <span class="hlt">rings</span> has been reported, but little is known about the effects of these fungi on soil aggregation and the microbial community structure, particularly the communities that can bind soil particles. We studied three concentric zones of Agaricus lilaceps fairy <span class="hlt">rings</span> in Eastern Montana that stimulate western wheatgrass (Pascopyrum smithii): outside the <span class="hlt">ring</span> (OUT), inside the <span class="hlt">ring</span> (IN), and stimulated zone adjacent to the fungal fruiting bodies (SZ) to determine (1) soil aggregate proportion and stability, (2) the microbial community composition and the N-acetyl-β-D-glucosaminidase activity associated with bulk soil at 0-15 cm depth, (3) the predominant culturable bacterial communities that can bind to soil adhering to wheatgrass roots, and (4) the stimulation of wheatgrass production. In bulk soil, macroaggregates (4.75-2.00 and 2.00-0.25 mm) and aggregate stability increased in SZ compared to IN and OUT. The high ratio of fungal to bacteria (fatty acid methyl ester) and N-acetyl-β-D-glucosaminidase activity in SZ compared to IN and OUT suggest high fungal biomass. A soil sedimentation assay performed on the predominant isolates from root-adhering soil indicated more soil-binding bacteria in SZ than IN and OUT; Pseudomonas fluorescens and Stenotrophomonas maltophilia isolates predominated in SZ, whereas Bacillus spp. isolates predominated in IN and OUT. This study suggests that <span class="hlt">growth</span> stimulation of wheatgrass in A. lilaceps fairy <span class="hlt">rings</span> may be attributed to the activity of the fungus by enhancing soil aggregation of bulk soil at 0-15 cm depth and influencing the amount and functionality of specific predominant microbial communities in the wheatgrass root-adhering soil.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.P12A..03C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.P12A..03C"><span>Saturn's <span class="hlt">Rings</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cuzzi, J. N.</p> <p>2014-12-01</p> <p>The <span class="hlt">rings</span> are changing before our eyes; structure varies on all timescales and unexpected things have been discovered. Many questions have been answered, but some answers remain elusive (see Cuzzi et al 2010 for a review). Here we highlight the major <span class="hlt">ring</span> science progress over the mission to date, and describe new observations planned for Cassini's final three years. <span class="hlt">Ring</span> Composition and particle sizes: The <span class="hlt">rings</span> are nearly all water ice with no other ices - so why are they reddish? The C <span class="hlt">Ring</span> and Cassini Division are "dirtier" than the more massive B and A <span class="hlt">Rings</span>, as shown by near-IR and, recently, microwave observations. Particle sizes, from stellar and radio occultations, vary from place to place. <span class="hlt">Ring</span> structure, micro and macro: numerous spiral density waves and ubiquitous "self-gravity wakes" reveal processes which fostered planet formation in the solar system and elsewhere. However, big puzzles remain regarding the main <span class="hlt">ring</span> divisions, the C <span class="hlt">Ring</span> plateau structures, and the B <span class="hlt">Ring</span> irregular structure. Moonlets, inside and out, seen and unseen: Two gaps contain sizeable moonlets, but more gaps seem to contain none; even smaller embedded "propeller" objects wander, systematically or randomly, through the A <span class="hlt">ring</span>. Rubble pile ringmoons just outside the <span class="hlt">rings</span> may escaped from the <span class="hlt">rings</span>, and the recently discovered "Peggy" may be trying this as we watch. Impact bombardment of the <span class="hlt">rings</span>: Comet fragments set the <span class="hlt">rings</span> to rippling on century-timescales, and boulders crash through hourly; meanwhile, the constant hail of infalling Kuiper belt material has a lower mass flux than previously thought. Origin and Age of the <span class="hlt">Rings</span>: The <span class="hlt">ring</span> mass and bombardment play key roles. The <span class="hlt">ring</span> mass is well known everywhere but in the B <span class="hlt">Ring</span> (where most of it is). New models suggest how tidal breakup of evolving moons may have formed massive ancient <span class="hlt">rings</span>, of which the current <span class="hlt">ring</span> is just a shadow. During its last three years, the Cassini tour profile will allow entirely new</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.B11D0491M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.B11D0491M"><span>Influence of Tree-Scale Environmental Variability on Tree-<span class="hlt">Ring</span> Reconstructions of Temperature at Sonora Pass, CA</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ma, L.; Stine, A.</p> <p>2016-12-01</p> <p>Tree-<span class="hlt">ring</span> <span class="hlt">width</span> from treeline environments tend to covary with local interannual temperature variabilities. However, other environmental factors such as moisture and light availability may further modulate tree <span class="hlt">growth</span> in cold climates. We investigate the influence of various environmental factors on a tree-<span class="hlt">ring</span> record from a research plot near Sonora Pass, CA (38.32N, 119.64W; elev. 3130 m). This treeline ecotone is dominated by whitebark pine (Pinus albicaulis) growing as individuals and as stands, and at the transition between tree form and krummholtz. We surveyed all trees in the 160m x 90m site, mapping and coring all trees with a diameter at breast height greater than 10 cm. We use survey data to test for an influence of inter-tree competition on <span class="hlt">growth</span>. We also test for modulation of <span class="hlt">growth</span> by variation in distance from surface water, aspect and slope, and soil types. Initial result shows a relationship between tree <span class="hlt">ring</span> <span class="hlt">width</span> and local May-July temperature (R = 0.33, p < 0.01), suggesting summer temperature as a large-scale control on <span class="hlt">growth</span>. Incorporating the tree-level metadata, we test for the effect of spatial variability on mean <span class="hlt">growth</span> rate and on reconstructed temperatures. Trees that have larger or closer neighboring trees experience greater competition, and we hypothesize that competition will be inversely related to average <span class="hlt">growth</span> rate. Further, we test the sensitivity of <span class="hlt">ring-width</span> interannual variability to other non-temperature environmental drivers such as moisture availability, light competition, and spatial relations in the microenvironment. We hypothesize that trees that have ready access to light and water will likely produce <span class="hlt">ring</span> records more closely correlated with the temperature record, and thus will produce a temperature reconstruction with a higher signal-to-noise ratio; whereas trees that experience more microenvironment limitations or competition will produce <span class="hlt">ring</span> records resembling temperature and additional environmental factors or</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6093088','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6093088"><span>Possible red spruce decline: Contributions of tree-<span class="hlt">ring</span> analysis</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Van Deusen, P.C. ); Reams, G.A. ); Cook, E.R. )</p> <p>1991-01-01</p> <p>Debate continues about the cause of apparent unprecedented decreases in <span class="hlt">ring</span> <span class="hlt">width</span> at all elevations, and increasing levels of mortality at high elevations, in red spruce (Picea rubens) stands in the northeastern United States. These <span class="hlt">growth</span> and mortality trends are often used as evidence of red spruce decline, but the possibility remains that they may be occurring naturally. Two hypotheses are being used to explain the causes of red spruce <span class="hlt">growth</span> reduction across its range and increased levels of standing dead at some high-elevation sites. This article summarizes the basic evidence used by advocates of these hypotheses and discusses the strengths of their arguments. The information presented is based primarily on tree-<span class="hlt">ring</span> studies sponsored by the Forest Response Program, which is part of the National Acid Precipitation Assessment Program.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002APS..MAR.B3001B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002APS..MAR.B3001B"><span>Vortex formation in magnetic narrow <span class="hlt">rings</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bland, J. A. C.</p> <p>2002-03-01</p> <p>Underlying the current interest in magnetic elements is the possibility such systems provide both for the study of fundamental phenomena in magnetism (such as domain wall trapping and spin switching) and for technological applications, such as high density magnetic storage or magnetic random access memories (MRAM). One key issue is to control the magnetic switching precisely. To achieve this one needs first to have a well defined and reproducible remanent state, and second the switching process itself must be simple and reproducible. Among the many studied geometries, <span class="hlt">rings</span> are shown to exhibit several advantages over other geometries, in that they show relatively simple stable magnetic states at remanence, with fast and simple magnetisation switching mechanisms. This is borne out of our systematic investigation of the magnetic properties of epitaxial and polycrystalline Co <span class="hlt">rings</span>, where both the static, dynamic and transport properties have been studied. Magnetic measurements and micromagnetic simulations show that for appropriate <span class="hlt">ring</span> structures a two step switching process occurs at high fields, indicating the existence of two different stable states. In addition to the vortex state, which occurs at intermediate fields, we have identified a new bi-domain state, which we term the `onion state', corresponding to opposite circulation of the magnetisation in each half of the <span class="hlt">ring</span>. The magnetic elements were fabricated using a new technique based on the pre-patterning of Si <span class="hlt">ring</span> structures and subsequent epitaxial <span class="hlt">growth</span> of Cu/Co/Cu sandwich films on top of the Si elements. This technique has allowed the <span class="hlt">growth</span> of epitaxial fcc Co(001) structures and in contrast to conventional lithographic methods, no damage to the magnetic layer structure is introduced by the patterning process [1,2]. We have studied the magnetic switching properties of arrays of narrow Co(100) epitaxial <span class="hlt">ring</span> magnets, with outer diameters between 1 μm and 2 μm, varying inner diameters and varying</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22308169','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22308169"><span><span class="hlt">Width</span> dependent transition of quantized spin-wave modes in Ni{sub 80}Fe{sub 20} square nanorings</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Banerjee, Chandrima; Saha, Susmita; Barman, Saswati; Barman, Anjan; Rousseau, Olivier; Otani, YoshiChika</p> <p>2014-10-28</p> <p>We investigated optically induced ultrafast magnetization dynamics in square shaped Ni{sub 80}Fe{sub 20} nanorings with varying <span class="hlt">ring</span> <span class="hlt">width</span>. Rich spin-wave spectra are observed whose frequencies showed a strong dependence on the <span class="hlt">ring</span> <span class="hlt">width</span>. Micromagnetic simulations showed different types of spin-wave modes, which are quantized upto very high quantization number. In the case of widest <span class="hlt">ring</span>, the spin-wave mode spectrum shows quantized modes along the applied field direction, which is similar to the mode spectrum of an antidot array. As the <span class="hlt">ring</span> <span class="hlt">width</span> decreases, additional quantization in the azimuthal direction appears causing mixed modes. In the narrowest <span class="hlt">ring</span>, the spin-waves exhibit quantization solely in azimuthal direction. The different quantization is attributed to the variation in the internal field distribution for different <span class="hlt">ring</span> <span class="hlt">width</span> as obtained from micromagnetic analysis and supported by magnetic force microscopy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA02224&hterms=Neptune&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DNeptune','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA02224&hterms=Neptune&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DNeptune"><span>Neptune's <span class="hlt">rings</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1999-01-01</p> <p>This 591-second exposure of the <span class="hlt">rings</span> of Neptune were taken with the clear filter by the Voyager 2 wide-angle camera. The two main <span class="hlt">rings</span> are clearly visible and appear complete over the region imaged. Also visible in this image is the inner faint <span class="hlt">ring</span> and the faint band which extends smoothly from the <span class="hlt">ring</span> roughly halfway between the two bright <span class="hlt">rings</span>. Both of these newly discovered <span class="hlt">rings</span> are broad and much fainter than the two narrow <span class="hlt">rings</span>. The bright glare is due to over-exposure of the crescent on Neptune. Numerous bright stars are evident in the background. Both bright <span class="hlt">rings</span> have material throughout their entire orbit, and are therefore continuous. The Voyager Mission is conducted by JPL for NASA's Office of Space Science and Applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA08361.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA08361.html"><span><span class="hlt">Ring</span> World</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2007-03-01</p> <p>Our robotic emissary, flying high above Saturn, captured this view of an alien copper-colored <span class="hlt">ring</span> world. The overexposed planet has deliberately been removed to show the unlit <span class="hlt">rings</span> alone, seen from an elevation of 60 degrees</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA02224.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA02224.html"><span>Neptune <span class="hlt">Rings</span></span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>1999-10-29</p> <p>This 591-second exposure of the <span class="hlt">rings</span> of Neptune were taken with the clear filter by NASA Voyager 2 wide-angle camera. The two main <span class="hlt">rings</span> are clearly visible and appear complete over the region imaged.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA12747.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA12747.html"><span><span class="hlt">Ring</span> Backdrop</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2011-01-03</p> <p>Saturn moon Enceladus brightly reflects sunlight before a backdrop of the planet <span class="hlt">rings</span> and the <span class="hlt">rings</span> shadows cast onto the planet. NASA Cassini spacecraft captured this snapshot during its flyby of the moon on Nov. 30, 2010.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JHyd..529..640C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JHyd..529..640C"><span>Total water storage dynamics derived from tree-<span class="hlt">ring</span> records and terrestrial gravity observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Creutzfeldt, Benjamin; Heinrich, Ingo; Merz, Bruno</p> <p>2015-10-01</p> <p>For both societal and ecological reasons, it is important to understand past and future subsurface water dynamics but estimating subsurface water storage is notoriously difficult. In this pilot study, we suggest the reconstruction of subsurface water dynamics by a multi-disciplinary approach combining hydrology, dendrochronology and geodesy. In a first step, nine complete years of high-precision gravimeter observations are used to estimate water storage changes in the subsurface at the Geodetic Observatory Wettzell in the Bavarian Forest, Germany. The record is extended to 63 years by calibrating a hydrological model against the 9 years of gravimeter observations. The relationship between tree-<span class="hlt">ring</span> <span class="hlt">growth</span> and water storage changes is evaluated as well as that between tree-<span class="hlt">ring</span> <span class="hlt">growth</span> and supplementary hydro-meteorological data. Results suggest that tree-<span class="hlt">ring</span> <span class="hlt">growth</span> is influenced primarily by subsurface water storage. Other variables related to the overall moisture status (e.g., Standardized Precipitation Index, Palmer Drought Severity Index, streamflow) are also strongly correlated with tree-<span class="hlt">ring</span> <span class="hlt">width</span>. While these indices are all indicators of water stored in the landscape, water storage changes of the subsurface estimated by depth-integral measurements give us the unique opportunity to directly reconstruct subsurface water storage dynamics from records of tree-<span class="hlt">ring</span> <span class="hlt">width</span>. Such long reconstructions will improve our knowledge of past water storage variations and our ability to predict future developments. Finally, knowing the relationship between subsurface storage dynamics and tree-<span class="hlt">ring</span> <span class="hlt">growth</span> improves the understanding of the different signal components contained in tree-<span class="hlt">ring</span> chronologies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21699247','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21699247"><span><span class="hlt">Ring</span>-opening copolymerization of maleic anhydride with epoxides: a chain-<span class="hlt">growth</span> approach to unsaturated polyesters.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>DiCiccio, Angela M; Coates, Geoffrey W</p> <p>2011-07-20</p> <p>We report the <span class="hlt">ring</span>-opening copolymerization of maleic anhydride with a variety of epoxides catalyzed by a chromium(III) salen complex. Quantitative isomerization of the cis-maleate form of all polymers affords the trans-fumarate analogues. Addition of chain transfer reagents yields low M(n), narrow PDI polymer samples. This method provides access to a range of new unsaturated polyesters with versatile functionality, as well as the first synthesis of high molecular weight poly(propylene fumarate).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/53072','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/53072"><span>Missing <span class="hlt">Rings</span>, Synchronous <span class="hlt">Growth</span>, and Ecological Disturbance in a 36-Year Pitch Pine (Pinus rigida) Provenance Study</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Caroline Leland; John Hom; Nicholas Skowronski; F. Thomas Ledig; Paul J. Krusic; Edward R. Cook; Dario Martin-Benito; Javier Martin-Fernandez; Neil Pederson; Dusan Gomory</p> <p>2016-01-01</p> <p>Provenance studies are an increasingly important analog for understanding how trees adapted to particular climatic conditions might respond to climate change. Dendrochronological analysis can illuminate differences among trees from different seed sources in terms of absolute annual <span class="hlt">growth</span> and sensitivity to external <span class="hlt">growth</span> factors. We analyzed annual radial <span class="hlt">growth</span> of...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28861237','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28861237"><span>Nonannual tree <span class="hlt">rings</span> in a climate-sensitive Prioria copaifera chronology in the Atrato River, Colombia.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Herrera-Ramirez, David; Andreu-Hayles, Laia; Del Valle, Jorge I; Santos, Guaciara M; Gonzalez, Paula L M</p> <p>2017-08-01</p> <p>In temperate climates, tree <span class="hlt">growth</span> dormancy usually ensures the annual nature of tree <span class="hlt">rings</span>, but in tropical environments, determination of annual periodicity can be more complex. The purposes of the work are as follows: (1) to generate a reliable tree-<span class="hlt">ring</span> <span class="hlt">width</span> chronology for Prioria copaifera Griseb. (Leguminoceae), a tropical tree species dwelling in the Atrato River floodplains, Colombia; (2) to assess the climate signal recorded by the tree-<span class="hlt">ring</span> records; and (3) to validate the annual periodicity of the tree <span class="hlt">rings</span> using independent methods. We used standard dendrochronological procedures to generate the P. copaifera tree-<span class="hlt">ring</span> chronology. We used Pearson correlations to evaluate the relationship of the chronology with the meteorological records, climate regional indices, and gridded precipitation/sea surface temperature products. We also evaluated 24 high-precision (14)C measurements spread over a range of preselected tree <span class="hlt">rings</span>, with assigned calendar years by dendrochronological techniques, before and after the bomb spike in order to validate the annual nature of the tree <span class="hlt">rings</span>. The tree-<span class="hlt">ring</span> <span class="hlt">width</span> chronology was statistically reliable, and it correlated significantly with local records of annual and October-December (OND) streamflow and precipitation across the upper river watershed (positive), and OND temperature (negative). It was also significantly related to the Oceanic Niño Index, Pacific Decadal Oscillation, and the Southern Oscillation Index, as well as sea surface temperatures over the Caribbean and the Pacific region. However, (14)C high-precision measurements over the tree <span class="hlt">rings</span> demonstrated offsets of up to 40 years that indicate that P. copaifera can produce more than one <span class="hlt">ring</span> in certain years. Results derived from the strongest climate-<span class="hlt">growth</span> relationship during the most recent years of the record suggest that the climatic signal reported may be due to the presence of annual <span class="hlt">rings</span> in some of those trees in recent years. Our study alerts</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013NatSR...3E1276S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013NatSR...3E1276S"><span>Gravitational Vortices And Clump Formation In Saturn's F <span class="hlt">ring</span> During An Encounter With Prometheus</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sutton, Phil J.; Kusmartsev, Feodor V.</p> <p>2013-02-01</p> <p>Saturn <span class="hlt">rings</span> are most beautiful and dynamic places in the solar system, consisting of ice particles in a constant battle between the gravitational forces of Saturn and its many moons. Fan, spiral, propellers, moonlets and streamer-channels observed by CASSINI in the F-<span class="hlt">ring</span> have been attributed to encounters by Prometheus on the F <span class="hlt">ring</span>, with investigations of optical thickness revealing large populations of transient moonlets. Taking into account gravitational interaction between particles and a multi-stranded F-<span class="hlt">ring</span> structure we show that Prometheus' encounters create rotational flows, like atmospheric vortices and the self-gravity enhances the accelerated <span class="hlt">growth</span> and size of moonlets. Vortex patches form caustics, which is a primary cause of the transient particle density clumps of 20 km <span class="hlt">width</span> and 100 km length, and they are elongated to cover an area of 1600 km by 150 km, which may eventually combine into a vortex sheet.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3572473','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3572473"><span>Gravitational Vortices And Clump Formation In Saturn's F <span class="hlt">ring</span> During An Encounter With Prometheus</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Sutton, Phil J.; Kusmartsev, Feodor V.</p> <p>2013-01-01</p> <p>Saturn <span class="hlt">rings</span> are most beautiful and dynamic places in the solar system, consisting of ice particles in a constant battle between the gravitational forces of Saturn and its many moons. Fan, spiral, propellers, moonlets and streamer-channels observed by CASSINI in the F-<span class="hlt">ring</span> have been attributed to encounters by Prometheus on the F <span class="hlt">ring</span>, with investigations of optical thickness revealing large populations of transient moonlets. Taking into account gravitational interaction between particles and a multi-stranded F-<span class="hlt">ring</span> structure we show that Prometheus' encounters create rotational flows, like atmospheric vortices and the self-gravity enhances the accelerated <span class="hlt">growth</span> and size of moonlets. Vortex patches form caustics, which is a primary cause of the transient particle density clumps of 20 km <span class="hlt">width</span> and 100 km length, and they are elongated to cover an area of 1600 km by 150 km, which may eventually combine into a vortex sheet. PMID:23429480</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23429480','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23429480"><span>Gravitational vortices and clump formation in Saturn's F <span class="hlt">ring</span> during an encounter with Prometheus.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sutton, Phil J; Kusmartsev, Feodor V</p> <p>2013-01-01</p> <p>Saturn <span class="hlt">rings</span> are most beautiful and dynamic places in the solar system, consisting of ice particles in a constant battle between the gravitational forces of Saturn and its many moons. Fan, spiral, propellers, moonlets and streamer-channels observed by CASSINI in the F-<span class="hlt">ring</span> have been attributed to encounters by Prometheus on the F <span class="hlt">ring</span>, with investigations of optical thickness revealing large populations of transient moonlets. Taking into account gravitational interaction between particles and a multi-stranded F-<span class="hlt">ring</span> structure we show that Prometheus' encounters create rotational flows, like atmospheric vortices and the self-gravity enhances the accelerated <span class="hlt">growth</span> and size of moonlets. Vortex patches form caustics, which is a primary cause of the transient particle density clumps of 20 km <span class="hlt">width</span> and 100 km length, and they are elongated to cover an area of 1600 km by 150 km, which may eventually combine into a vortex sheet.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.9015P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.9015P"><span>A 500-year dual stable isotope tree <span class="hlt">ring</span> chronology of a Late Glacial cooling event</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pauly, Maren; Helle, Gerhard; Büntgen, Ulf; Friedrich, Michael; Heinrich, Ingo; Kromer, Bernd; Nievergelt, Daniel; Reinig, Frederick; Riedel, Frank; Sookdeo, Adam; Treydte, Kerstin; Wacker, Lukas; Brauer, Achim</p> <p>2017-04-01</p> <p>A recent discovery of over 250 subfossil pine trees in Zürich (dated 14 000 - 11 000 cal BP) has provided the opportunity to study the inconsistent warming transition from the last ice age to the current interglacial. This period (the Late Glacial) has been extensively studied through the development of mostly non-tree <span class="hlt">ring</span> palaeoclimate proxy records due to the intrigue of numerous prominent climate oscillations. However, such existing (lake sediment and ice core) records often lack the temporal resolution required to interpret rapid environmental changes. Tree <span class="hlt">rings</span> can help to resolve such events due to their high resolution (annually-resolved) <span class="hlt">growth</span> banding and absolute dating potential. Moreover, the analysis of stable isotopes can strongly improve the climate signal implemented in tree-<span class="hlt">ring</span> <span class="hlt">width</span>. Since numerous environmental conditions are all integrated in the rather simple <span class="hlt">ring-width</span> series, measurements of chemical tree responses (via stable isotopes) can greatly refine the climate-<span class="hlt">growth</span>-dynamics. In this study, we are developing a well replicated 500-year annually resolved dual stable isotope (δ18O, δ13C) chronology from tree-<span class="hlt">ring</span> cellulose, in an effort to reconstruct the environmental dynamics of a short-term Late Glacial cooling event (13 950 - 13 450 cal BP) in an otherwise naturally warming world. We will present and discuss the biological response to this rapid climate oscillation in the face of low atmospheric CO2 concentrations and other site conditions without any human fingerprint.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApSS..329..137X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApSS..329..137X"><span>Facile solvothermal synthesis of abnormal <span class="hlt">growth</span> of one-dimensional ZnO nanostructures by <span class="hlt">ring</span>-opening reaction of polyvinylpyrrolidone</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xu, G.; Wang, X. L.; Liu, G. Z.</p> <p>2015-02-01</p> <p>Abnormal <span class="hlt">growth</span> of one-dimensional (1-D) ZnO nanostructures (NSs) have been accomplished with the assistance of polyvinylpyrrolidone (PVP) under a super high alkaline alcoholic solvothermal condition. The products were characterized by transmission electron microscopy (TEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and proton nuclear magnetic resonance (1H NMR) spectroscopy. The effect of synthetic conditions, such as reaction temperature and the addition of PVP, on the morphologies of ZnO products were investigated. The results show that PVP molecules had the significant role in the transformation of morphologies of ZnO NSs ranging from nanorods, nanoparticles to pyramids, as well as flower-like assembly features. The possible <span class="hlt">growth</span> mechanism of ZnO pyramids was proposed based on <span class="hlt">ring</span>-opening reaction of PVP.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20100042208','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20100042208"><span>Stacked Corrugated Horn <span class="hlt">Rings</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sosnowski, John B.</p> <p>2010-01-01</p> <p>This Brief describes a method of machining and assembly when the depth of corrugations far exceeds the <span class="hlt">width</span> and conventional machining is not practical. The horn is divided into easily machined, individual <span class="hlt">rings</span> with shoulders to control the depth. In this specific instance, each of the corrugations is identical in profile, and only differs in diameter and outer profile. The horn is segmented into <span class="hlt">rings</span> that are cut with an interference fit (zero clearance with all machining errors biased toward contact). The interference faces can be cut with a reverse taper to increase the holding strength of the joint. The taper is a compromise between the interference fit and the clearance of the two faces during assembly. Each internal <span class="hlt">ring</span> is dipped in liquid nitrogen, then nested in the previous, larger <span class="hlt">ring</span>. The <span class="hlt">ring</span> is rotated in the nest until the temperature of the two parts equalizes and the pieces lock together. The resulting assay is stable, strong, and has an internal finish that cannot be achieved through other methods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/5825072','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/5825072"><span>Radiation densitometry in tree-<span class="hlt">ring</span> analysis: a review and procedure manual</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Parker, M.L.; Taylor, F.G.; Doyle, T.W.; Foster, B.E.; Cooper, C.; West, D.C.</p> <p>1985-01-01</p> <p>An x-ray densitometry of wood facility is being established by the Environmental Sciences Division, Oak Ridge Natioanl Laboratory (ORNL). The objective is to apply tree-<span class="hlt">ring</span> data to determine whether or not there is a fertilizer effect on tree <span class="hlt">growth</span> from increased atmospheric carbon dioxide since the beginning of the industrial era. Intra-<span class="hlt">ring</span> <span class="hlt">width</span> and density data, including <span class="hlt">ring</span>-mass will be detemined from tree-<span class="hlt">ring</span> samples collected from sites located throughout the United States and Canada. This report is designed as a guide to assist ORNL scientists in building the x-ray densitometry system. The history and development of x-ray densitometry in tree-<span class="hlt">ring</span> research is examined and x-ray densitometry is compared with other techniques. Relative wood and tree characteristics are described as are environmental and genetic factors affecting tree <span class="hlt">growth</span> responses. Methods in x-ray densitometry are examined in detail and the techniques used at four operating laboratories are described. Some ways that dendrochronology has been applied in dating, in wood quality, and environmental studies are presented, and a number of tree-<span class="hlt">ring</span> studies in Canada are described. An annotated bibliography of radiation densitometry in tree-<span class="hlt">ring</span> analysis and related subjects is included.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013pss3.book..309T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013pss3.book..309T"><span>Planetary <span class="hlt">Rings</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tiscareno, Matthew S.</p> <p></p> <p>Planetary <span class="hlt">rings</span> are the only nearby astrophysical disks and the only disks that have been investigated by spacecraft (especially the Cassini spacecraft orbiting Saturn). Although there are significant differences between <span class="hlt">rings</span> and other disks, chiefly the large planet/<span class="hlt">ring</span> mass ratio that greatly enhances the flatness of <span class="hlt">rings</span> (aspect ratios as small as 10- 7), understanding of disks in general can be enhanced by understanding the dynamical processes observed at close range and in real time in planetary <span class="hlt">rings</span>.We review the known <span class="hlt">ring</span> systems of the four giant planets, as well as the prospects for <span class="hlt">ring</span> systems yet to be discovered. We then review planetary <span class="hlt">rings</span> by type. The A, B, and C <span class="hlt">rings</span> of Saturn, plus the Cassini Division, comprise our solar system's only dense broad disk and host many phenomena of general application to disks including spiral waves, gap formation, self-gravity wakes, viscous overstability and normal modes, impact clouds, and orbital evolution of embedded moons. Dense narrow <span class="hlt">rings</span> are found both at Uranus (where they comprise the main <span class="hlt">rings</span> entirely) and at Saturn (where they are embedded in the broad disk) and are the primary natural laboratory for understanding shepherding and self-stability. Narrow dusty <span class="hlt">rings</span>, likely generated by embedded source bodies, are surprisingly found to sport azimuthally confined arcs at Neptune, Saturn, and Jupiter. Finally, every known <span class="hlt">ring</span> system includes a substantial component of diffuse dusty <span class="hlt">rings</span>.Planetary <span class="hlt">rings</span> have shown themselves to be useful as detectors of planetary processes around them, including the planetary magnetic field and interplanetary impactors as well as the gravity of nearby perturbing moons. Experimental <span class="hlt">rings</span> science has made great progress in recent decades, especially numerical simulations of self-gravity wakes and other processes but also laboratory investigations of coefficient of restitution and spectroscopic ground truth. The age of self-sustained <span class="hlt">ring</span> systems is a matter of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JGRA..117.6223C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JGRA..117.6223C"><span>Statistical <span class="hlt">ring</span> current of Saturn</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Carbary, J. F.; Achilleos, N.; Arridge, C. S.</p> <p>2012-06-01</p> <p>The statistical <span class="hlt">ring</span> current of Saturn has been determined from the curl of the median magnetic field derived from over 5 years of observations of the Cassini magnetometer. The main issue addressed here is the calculation of the statistical <span class="hlt">ring</span> current of Saturn by directly computing, for the first time, the symmetrical part of the <span class="hlt">ring</span> current J from the Maxwell equation ∇ × B = μ0J from assembling the perturbation magnetic field B from 2004 through 2010. This study validates previous studies, based on fewer data and not using ∇ × B, and shows that the <span class="hlt">ring</span> current flows eastward (in the +ϕ or corotation direction) and extends from ˜3 RS to at least ˜20 RS (1 RS = 60,268 km), which is the vicinity of the dayside magnetopause; that the <span class="hlt">ring</span> current has a peak strength of ˜75 pA/m2 at ˜9.5 RS; and that the <span class="hlt">ring</span> current has a half-<span class="hlt">width</span> of ˜1.5 RS. Two outcomes of this study are that the <span class="hlt">ring</span> current bends northward, as suggested by the “bowl” model of Saturn's plasma sheet, and that the total <span class="hlt">ring</span> current is 9.2 ± 1.0 MA. In the context of future endeavors, the statistical <span class="hlt">ring</span> current presented here can be used for calculations of the magnetic field of Saturn for particle drifts, field line mapping, and J × B force.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27639018','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27639018"><span>Negative feedback adjustment challenges reconstruction study from tree <span class="hlt">rings</span>: A study case of response of Populus euphratica to river discontinuous flow and ecological water conveyance.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ling, Hongbo; Zhang, Pei; Guo, Bin; Xu, Hailiang; Ye, Mao; Deng, Xiaoya</p> <p>2017-01-01</p> <p>Drought stress changes the relationship between the <span class="hlt">growth</span> of tree <span class="hlt">rings</span> and variations in ambient temperature. However, it is not clear how the <span class="hlt">growth</span> of trees changes in response to drought of varying intensities, especially in arid areas. Therefore, Tree <span class="hlt">rings</span> were studied for 6years in Populus euphratica to assess the impacts of abrupt changes in environment on tree <span class="hlt">rings</span> using the theories and methods in dendrohydrology, ecology and phytophysiology. The <span class="hlt">width</span> of tree <span class="hlt">rings</span> increased by 8.7% after ecological water conveyance downstream of Tarim River compared to that when the river water had been cut off. However, during intermediate drought, as the depth of the groundwater increases, the downward trend in the tree <span class="hlt">rings</span> was reversed because of changes in the physiology of the tree. Therefore, the <span class="hlt">growth</span> of tree <span class="hlt">rings</span> shows a negative feedback to intermediate drought stress, an observation that challenges the homogenization theory of tree <span class="hlt">ring</span> reconstruction based on the traditional methods. Owing to the time lag, the cumulative effect and the negative feedback between the <span class="hlt">growth</span> of tree <span class="hlt">rings</span> and drought stress, the reconstruction of past environment by studying the patterns of tree <span class="hlt">rings</span> is often inaccurate. Our research sets out to verify the hypothesis that intermediate drought stress results in a negative feedback adjustment and thus to answers two scientific questions: (1) How does the negative feedback adjustment promote the <span class="hlt">growth</span> of tree <span class="hlt">rings</span> as a result of intermediate drought stress? (2) How does the negative feedback adjustment lower the accuracy with which the past is reconstructed based on tree <span class="hlt">rings</span>? This research not only enriches the connotations of intermediate disturbance hypothesis and reconstruction theory of tree <span class="hlt">rings</span>, but also provides a scientific basis for the conservation of desert riparian forests worldwide. Copyright © 2016 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920062464&hterms=slip+ring&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dslip%2Bring','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920062464&hterms=slip+ring&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dslip%2Bring"><span>Vortex <span class="hlt">rings</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shariff, Karim; Leonard, Anthony</p> <p>1992-01-01</p> <p>The vortex-<span class="hlt">ring</span> problem in fluid mechanics is examined generally in terms of formation, the steady state, the duration of the <span class="hlt">rings</span>, and vortex interactions. The formation is studied by examining the generation of laminar and turbulent vortex <span class="hlt">rings</span> and their resulting structures with attention given to the three stages of laminar <span class="hlt">ring</span> development. Inviscid dynamics is addressed to show how core dynamics affects overall <span class="hlt">ring</span> motion, and laminar vortex structures are described in two dimensions. Viscous and inviscid structures are related in terms of 'leapfrogging', head-on collisions, and collisions with a no-slip wall. Linear instability theory is shown to successfully describe observational data, although late stages in the breakdown are not completely understood. This study of vortex <span class="hlt">rings</span> has important implications for key aerodynamic issues including sound generation, transport and mixing, and vortex interactions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1995Geo....23..109S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995Geo....23..109S"><span>Tree-<span class="hlt">ring</span> responses to the 1978 earthquake at Stephens Pass, northeastern California</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sheppard, Paul R.; White, Lester O.</p> <p>1995-02-01</p> <p>The 1978 earthquake at Stephens Pass, northeastern California, dropped a series of grabens that average 4.5 m in <span class="hlt">width</span>, extend up to 1 m in depth, and are found intermittently along a 2-km-long rupture zone. The formation of this graben series killed or otherwise affected many trees growing in or immediately adjacent to the rupture zone. Nine trees responded to the 1978 earthquake with anomalously narrow <span class="hlt">ring</span> <span class="hlt">widths</span>, beginning in 1979 and continuing for several years. One tree responded with anomalously wide latewood relative to total <span class="hlt">ring</span> <span class="hlt">width</span>. This example of tree-<span class="hlt">ring</span> responses to a normal-fault earthquake complements other cases of tree-<span class="hlt">growth</span> responses to earthquakes of thrust and strike-slip tectonic settings. The 1978 earthquake at Stephens Pass was unique in that it caused tree-<span class="hlt">ring</span> responses even though it was only moderate (magnitude 4.6). This study serves as a specific calibration example for dendrochronologically studying prehistoric earthquakes, as well as eruptions, at the nearby Medicine Lake Highlands. Medicine Lake has been seismically and volcanically active during the past 1000 yr, and it supports a forest of several coniferous tree species that can be used for dendrochronologically studying geomorphological processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA18295.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA18295.html"><span>Translucent <span class="hlt">Rings</span></span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2014-12-08</p> <p>Although solid-looking in many images, Saturn's <span class="hlt">rings</span> are actually translucent. In this picture, we can glimpse the shadow of the <span class="hlt">rings</span> on the planet through (and below) the A and C <span class="hlt">rings</span> themselves, towards the lower right hand corner. For centuries people have studied Saturn's <span class="hlt">rings</span>, but questions about the structure and composition of the <span class="hlt">rings</span> lingered. It was only in 1857 when the physicist James Clerk Maxwell demonstrated that the <span class="hlt">rings</span> must be composed of many small particles and not solid <span class="hlt">rings</span> around the planet, and not until the 1970s that spectroscopic evidence definitively showed that the <span class="hlt">rings</span> are composed mostly of water ice. This view looks toward the sunlit side of the <span class="hlt">rings</span> from about 17 degrees above the ringplane. The image was taken with the Cassini spacecraft wide-angle camera on Aug. 12, 2014 in near-infrared light centered at 752 nanometers. The view was obtained at a distance of approximately 1.4 million miles (2.3 million kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 24 degrees. Image scale is 85 miles (136 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA18295</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110013548','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110013548"><span>Nuclear <span class="hlt">Rings</span> in Galaxies - A Kinematic Perspective</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mazzuca, Lisa M.; Swaters, Robert A.; Knapen, Johan H.; Veilleux, Sylvain</p> <p>2011-01-01</p> <p>We combine DensePak integral field unit and TAURUS Fabry-Perot observations of 13 nuclear <span class="hlt">rings</span> to show an interconnection between the kinematic properties of the <span class="hlt">rings</span> and their resonant origin. The nuclear <span class="hlt">rings</span> have regular and symmetric kinematics, and lack strong non-circular motions. This symmetry, coupled with a direct relationship between the position angles and ellipticities of the <span class="hlt">rings</span> and those of their host galaxies, indicate the <span class="hlt">rings</span> are in the same plane as the disc and are circular. From the rotation curves derived, we have estimated the compactness (v(sup 2)/r) up to the turnover radius, which is where the nuclear <span class="hlt">rings</span> reside. We find that there is evidence of a correlation between compactness and <span class="hlt">ring</span> <span class="hlt">width</span> and size. Radially wide <span class="hlt">rings</span> are less compact, and thus have lower mass concentration. The compactness increases as the <span class="hlt">ring</span> <span class="hlt">width</span> decreases. We also find that the nuclear <span class="hlt">ring</span> size is dependent on the bar strength, with weaker bars allowing <span class="hlt">rings</span> of any size to form.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1985PhRvL..54..377L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1985PhRvL..54..377L"><span>Masses, <span class="hlt">widths</span>, and leptonic <span class="hlt">widths</span> of the higher upsilon resonances</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lovelock, D. M.; Horstkotte, J. E.; Klopfenstein, C.; Lee-Franzini, J.; Romero, L.; Schamberger, R. D.; Youssef, S.; Franzini, P.; Son, D.; Tuts, P. M.; Zhao, T.; Herb, S.; Dietl, H.; Eigen, G.; Fonseca, V.; Lorenz, E.; Mageras, G.; Han, K.; Imlay, R.; Metcalf, W.; Sreedhar, V.</p> <p>1985-02-01</p> <p>The masses, total <span class="hlt">widths</span>, and leptonic <span class="hlt">widths</span> of three triplet s-wave bb¯ states Υ(4S), Υ(5S), and Υ(6S) are determined from measurements of the e+e- annihilation cross section into hadrons for 10.55<W<11.25 GeV. The resonances are identified from potential model results and their properties are obtained with the help of a simplified coupled-channels calculation. We find M(4S)=10.577 GeV, Γ(4S)=25 MeV, Γee(4S)=0.28 keV; M(5S)=10.845 GeV, Γ(5S)=110 MeV, Γee(5S)=0.37 keV; M(6S)=11.02 GeV, Γ(6S)=90 MeV, Γee(6S)=0.16 keV.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19963979','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19963979"><span>Relation between index finger <span class="hlt">width</span> and hand <span class="hlt">width</span> anthropometric measures.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Komandur, Sashidharan; Johnson, Peter W; Storch, Richard L; Yost, Michael G</p> <p>2009-01-01</p> <p>Measures of hand and finger anthropometry are very important for designing many hand held devices as well as understanding anthropometric effects on the operation of such devices. Many historical datasets have measured and recorded gross hand dimensions but do not often record the finer dimensions of the hand such as finger anthropometry. Knowing the size and mass of fingers across genders can be critical to the design and operation of hand held devices. In this paper we compare two empirical linear models that predicts index finger <span class="hlt">width</span> at the proximal interphalangeal (PIP) joint (a finger anthropometric measure) based on hand-<span class="hlt">width</span> (hand anthropometric measure). This will be especially useful for deriving population measures of finger anthropometry from large historical data sets where only gross hand dimensions are available.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3423803','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3423803"><span>Fluctuations of cambial activity in relation to precipitation result in annual <span class="hlt">rings</span> and intra-annual <span class="hlt">growth</span> zones of xylem and phloem in teak (Tectona grandis) in Ivory Coast</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Dié, Agathe; Kitin, Peter; Kouamé, François N'Guessan; Van den Bulcke, Jan; Van Acker, Joris; Beeckman, Hans</p> <p>2012-01-01</p> <p>Background and Aims Teak forms xylem <span class="hlt">rings</span> that potentially carry records of carbon sequestration and climate in the tropics. These records are only useful when the structural variations of tree <span class="hlt">rings</span> and their periodicity of formation are known. Methods The seasonality of <span class="hlt">ring</span> formation in mature teak trees was examined via correlative analysis of cambial activity, xylem and phloem formation, and climate throughout 1·5 years. Xylem and phloem differentiation were visualized by light microscopy and scanning electron microscopy. Key Results A 3 month dry season resulted in semi-deciduousness, cambial dormancy and formation of annual xylem <span class="hlt">growth</span> <span class="hlt">rings</span> (AXGRs). Intra-annual xylem and phloem <span class="hlt">growth</span> was characterized by variable intensity. Morphometric features of cambium such as cambium thickness and differentiating xylem layers were positively correlated. Cambium thickness was strongly correlated with monthly rainfall (R2 = 0·7535). In all sampled trees, xylem <span class="hlt">growth</span> zones (XGZs) were formed within the AXGRs during the seasonal development of new foliage. When trees achieved full leaf, the xylem in the new XGZs appeared completely differentiated and functional for water transport. Two phloem <span class="hlt">growth</span> <span class="hlt">rings</span> were formed in one growing season. Conclusions The seasonal formation pattern and microstructure of teak xylem suggest that AXGRs and XGZs can be used as proxies for analyses of the tree history and climate at annual and intra-annual resolution. PMID:22805529</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22805529','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22805529"><span>Fluctuations of cambial activity in relation to precipitation result in annual <span class="hlt">rings</span> and intra-annual <span class="hlt">growth</span> zones of xylem and phloem in teak (Tectona grandis) in Ivory Coast.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dié, Agathe; Kitin, Peter; Kouamé, François N'guessan; Van den Bulcke, Jan; Van Acker, Joris; Beeckman, Hans</p> <p>2012-09-01</p> <p>Teak forms xylem <span class="hlt">rings</span> that potentially carry records of carbon sequestration and climate in the tropics. These records are only useful when the structural variations of tree <span class="hlt">rings</span> and their periodicity of formation are known. The seasonality of <span class="hlt">ring</span> formation in mature teak trees was examined via correlative analysis of cambial activity, xylem and phloem formation, and climate throughout 1·5 years. Xylem and phloem differentiation were visualized by light microscopy and scanning electron microscopy. A 3 month dry season resulted in semi-deciduousness, cambial dormancy and formation of annual xylem <span class="hlt">growth</span> <span class="hlt">rings</span> (AXGRs). Intra-annual xylem and phloem <span class="hlt">growth</span> was characterized by variable intensity. Morphometric features of cambium such as cambium thickness and differentiating xylem layers were positively correlated. Cambium thickness was strongly correlated with monthly rainfall (R(2) = 0·7535). In all sampled trees, xylem <span class="hlt">growth</span> zones (XGZs) were formed within the AXGRs during the seasonal development of new foliage. When trees achieved full leaf, the xylem in the new XGZs appeared completely differentiated and functional for water transport. Two phloem <span class="hlt">growth</span> <span class="hlt">rings</span> were formed in one growing season. The seasonal formation pattern and microstructure of teak xylem suggest that AXGRs and XGZs can be used as proxies for analyses of the tree history and climate at annual and intra-annual resolution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA12592.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA12592.html"><span>Widening <span class="hlt">Rings</span></span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2010-03-18</p> <p>Saturn <span class="hlt">rings</span> and its moon Rhea are imaged before a crescent of the planet in this image captured by NASA Cassini spacecraft. The shadows of the <span class="hlt">rings</span> continue to grow wider after their disappearing act during the planet August 2009 equinox.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20020005141&hterms=Electromagnetism&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DElectromagnetism','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20020005141&hterms=Electromagnetism&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DElectromagnetism"><span>Planetary <span class="hlt">Rings</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cuzzi, Jeffrey N.</p> <p>1994-01-01</p> <p>Just over two decades ago, Jim Pollack made a critical contribution to our understanding of planetary <span class="hlt">ring</span> particle properties, and resolved a major apparent paradox between radar reflection and radio emission observations. At the time, particle properties were about all there were to study about planetary <span class="hlt">rings</span>, and the fundamental questions were, why is Saturn the only planet with <span class="hlt">rings</span>, how big are the particles, and what are they made of? Since then, we have received an avalanche of observations of planetary <span class="hlt">ring</span> systems, both from spacecraft and from Earth. Meanwhile, we have seen steady progress in our understanding of the myriad ways in which gravity, fluid and statistical mechanics, and electromagnetism can combine to shape the distribution of the submicron-to-several-meter size particles which comprise <span class="hlt">ring</span> systems into the complex webs of structure that we now know them to display. Insights gained from studies of these giant dynamical analogs have carried over into improved understanding of the formation of the planets themselves from particle disks, a subject very close to Jim's heart. The now-complete reconnaissance of the gas giant planets by spacecraft has revealed that <span class="hlt">ring</span> systems are invariably found in association with families of regular satellites, and there is ark emerging perspective that they are not only physically but causally linked. There is also mounting evidence that many features or aspects of all planetary <span class="hlt">ring</span> systems, if not the <span class="hlt">ring</span> systems themselves, are considerably younger than the solar system</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA18324.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA18324.html"><span><span class="hlt">Ring</span> Slicer</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2015-07-06</p> <p>Saturn's moon Prometheus, seen here looking suspiciously blade-like, is captured near some of its sculpting in the F <span class="hlt">ring</span>. Prometheus' (53 miles or 86 kilometers across) orbit sometimes takes it into the F <span class="hlt">ring</span>. When it enters the <span class="hlt">ring</span>, it leaves a gore where its gravitational influence clears out some of the smaller <span class="hlt">ring</span> particles. Below Prometheus, the dark lanes interior to the F <span class="hlt">ring</span>'s bright core provide examples of previous <span class="hlt">ring</span>-moon interactions. This view looks toward the unilluminated side of the <span class="hlt">rings</span> from about 7 degrees below the <span class="hlt">ring</span> plane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on March 15, 2015. The view was obtained at a distance of approximately 286,000 miles (461,000 kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 115 degrees. Image scale is 1.7 miles (2.8 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA18324</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20020005141&hterms=Electromagnetism&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DElectromagnetism','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20020005141&hterms=Electromagnetism&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DElectromagnetism"><span>Planetary <span class="hlt">Rings</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cuzzi, Jeffrey N.</p> <p>1994-01-01</p> <p>Just over two decades ago, Jim Pollack made a critical contribution to our understanding of planetary <span class="hlt">ring</span> particle properties, and resolved a major apparent paradox between radar reflection and radio emission observations. At the time, particle properties were about all there were to study about planetary <span class="hlt">rings</span>, and the fundamental questions were, why is Saturn the only planet with <span class="hlt">rings</span>, how big are the particles, and what are they made of? Since then, we have received an avalanche of observations of planetary <span class="hlt">ring</span> systems, both from spacecraft and from Earth. Meanwhile, we have seen steady progress in our understanding of the myriad ways in which gravity, fluid and statistical mechanics, and electromagnetism can combine to shape the distribution of the submicron-to-several-meter size particles which comprise <span class="hlt">ring</span> systems into the complex webs of structure that we now know them to display. Insights gained from studies of these giant dynamical analogs have carried over into improved understanding of the formation of the planets themselves from particle disks, a subject very close to Jim's heart. The now-complete reconnaissance of the gas giant planets by spacecraft has revealed that <span class="hlt">ring</span> systems are invariably found in association with families of regular satellites, and there is ark emerging perspective that they are not only physically but causally linked. There is also mounting evidence that many features or aspects of all planetary <span class="hlt">ring</span> systems, if not the <span class="hlt">ring</span> systems themselves, are considerably younger than the solar system</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1394918','SCIGOV-DOEDE'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1394918"><span>Tree <span class="hlt">Ring</span> Chronology Indexes and Reconstructions of Precipitation in Central Iowa, USA (1984) (NDP-002)</span></a></p> <p><a target="_blank" href="http://www.osti.gov/dataexplorer">DOE Data Explorer</a></p> <p>Blasing, T. J.; Duvick, D. N.</p> <p>2012-01-01</p> <p>Tree core samples (4 mm in diameter) were extracted from the trunks of white oak (Quercus alba) at three sites in central Iowa (Duvick Back Woods, Ledges State Park, and Pammel). At least 60 trees were sampled at each site, and at least two cores were taken from each tree. The <span class="hlt">growth</span> <span class="hlt">rings</span> of each core were dated by calendar year and measured; the measurements were then transformed into dimensionless <span class="hlt">ring-width</span> indices and correlated with annual precipitation. Data were collected for the years 1680 through 1979. Each tree <span class="hlt">ring</span> was characterized by the site, year, tree-<span class="hlt">ring-width</span> index, number of core samples, decade year, and the annual reconstructed precipitation estimate. These data have more than 50% of their variance in common with the known annual statewide average precipitation for Iowa and serve as useful indicators of the precipitation and drought history of the region for the past 300 years. The data are in two files: tree-<span class="hlt">ring</span>-chronology data (8 kB) and the annual reconstructed precipitation data for central Iowa (2 kB).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26789943','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26789943"><span>Directed <span class="hlt">Growth</span> of Polymer Nanorods Using Surface-Initiated <span class="hlt">Ring</span>-Opening Polymerization of N-Allyl N-Carboxyanhydride.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lu, Lu; Lahasky, Samuel H; Zhang, Donghui; Garno, Jayne C</p> <p>2016-02-17</p> <p>A stepwise chemistry route was used to prepare arrays of polymer nanostructures of poly(N-allyl glycine) on Si(111) using particle lithography. The nanostructures were used for studying surface reactions with advanced measurements of atomic force microscopy (AFM). In the first step to fabricate the surface platform, isolated nanopores were prepared within a thin film of octadecyltrichlorosilane (OTS). The OTS served as a surface resist, and the areas of nanopores provided multiple, regularly shaped sites for further reaction. An initiator, (3-aminopropyl)triethoxysilane (APTES), was grown selectively inside the nanopores to define sites for polymerization. The initiator attached selectively to the sites of nanopores indicating OTS prevented nonspecific adsorption. Surface-initiated <span class="hlt">ring</span>-opening polymerization of N-allyl N-carboxyanhydride with APTES produced polymer nanorods on the nanodots of APTES presenting amine functional groups. The surface changes for each step were monitored using high resolution atomic force microscopy (AFM). Slight variations in the height of the poly(N-allyl glycine) nanorods were observed which scale correspondingly to the initial dimensions of nanopores. The distance between adjacent polymer nanorods was controlled by the size of mesoparticle masks used in the experiment. This surface platform has potential application in biotechnology for smart coatings or biosensors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23202041','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23202041"><span>Numerical study of opto-fluidic <span class="hlt">ring</span> resonators for biosensor applications.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cho, Han Keun; Han, Jinwoo</p> <p>2012-10-22</p> <p>The opto-fluidic <span class="hlt">ring</span> resonator (OFRR) biosensor is numerically characterized in whispering gallery mode (WGM). The <span class="hlt">ring</span> resonator includes a <span class="hlt">ring</span>, a waveguide and a gap separating the <span class="hlt">ring</span> and the waveguide. Dependence of the resonance characteristics on the resonator size parameters such as the <span class="hlt">ring</span> diameter, the <span class="hlt">ring</span> thickness, the waveguide <span class="hlt">width</span>, and the gap <span class="hlt">width</span> between the <span class="hlt">ring</span> and the waveguide are investigated. For this purpose, we use the finite element method with COMSOL Multiphysics software to solve the Maxwell's equations. The resonance frequencies, the free spectral ranges (FSR), the full <span class="hlt">width</span> at half-maximum (FWHM), finesse (F), and quality factor of the resonances (Q) are examined. The resonant frequencies are dominantly affected by the resonator diameter while the gap <span class="hlt">width</span>, the <span class="hlt">ring</span> thickness and the waveguide <span class="hlt">width</span> have negligible effects on the resonant frequencies. FWHM, the quality factor Q and the finesse F are most strongly affected by the gap <span class="hlt">width</span> and moderately influenced by the <span class="hlt">ring</span> diameter, the waveguide <span class="hlt">width</span> and the <span class="hlt">ring</span> thickness. In addition, our simulation demonstrates that there is an optimum range of the waveguide <span class="hlt">width</span> for a given <span class="hlt">ring</span> resonator and this value is between ~2.25 μm and ~2.75 μm in our case.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1812343Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1812343Z"><span>Challenges in Establishing Multi-Millennial Tree <span class="hlt">Ring</span> Records for the Holocene</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ziehmer, Malin Michelle; Nicolussi, Kurt; Schlüchter, Christian; Leuenberger, Markus</p> <p>2016-04-01</p> <p>Recent finds of wood remains from glacier forefields and peat bogs along a SW-NE transect in the Alps represent a unique high-frequency archive which allows the reconstruction of climate variability over the entire Holocene. We use a multi-proxy approach that combines both tree <span class="hlt">ring</span> <span class="hlt">width</span> and multiple stable isotope chronologies by establishing highly resolved tree <span class="hlt">ring</span> and stable isotope records from calendar-dated wood covering the past 9000 years. Therefore, tree <span class="hlt">ring</span> <span class="hlt">width</span> and stable isotope series are generated by a standardized procedure, where first the tree <span class="hlt">ring</span> <span class="hlt">widths</span> are measured and samples are calendrically dated by means of tree <span class="hlt">ring</span> analysis. Afterwards, samples are cut into 5-year tree <span class="hlt">ring</span> blocks, cellulose is extracted and crushed by ultrasonic homogenization, and subsequently, the stable isotopes of carbon, oxygen and hydrogen are simultaneously measured. Although the sample preparation follows a standardized procedure, the establishment of the multi-millennial tree <span class="hlt">ring</span> and isotope chronologies is not straightforward. By investigating the individual measurement series from the Early and Mid-Holocene as well as recent samples from living trees from key sites - which will provide the connection of the Holocene tree <span class="hlt">ring</span> series to the present - the individual measurement series reveal effects due to different sampling sites, tree species, <span class="hlt">growth</span> trend, potential degree of decay and cellulose content. These specific effects influence both the tree <span class="hlt">ring</span> <span class="hlt">width</span>, and to a higher degree the stable isotope series. For instance, the measured deuterium records reveal a species-specific isotope signature for the investigated species Larix decidua and Pinus cembra, which is not resembled in the oxygen and carbon records. In order to establish stable isotope chronologies which span the time period from 9000 years b2k to the present, such tree specific features need to be corrected from the individual time series. In this study, we try to overcome these various</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3536236','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3536236"><span><span class="hlt">Ring</span> Infiltrate in Staphylococcal Keratitis</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wallang, Batriti S.; Sharma, Savitri; Sahu, Srikant K.; Mittal, Ruchi</p> <p>2013-01-01</p> <p>Smear and culture tests of corneal scrapings from a patient with a <span class="hlt">ring</span> infiltrate confirmed significant <span class="hlt">growth</span> of a Staphylococcus species resistant to fluoroquinolones. Because of nonresponse to medical management, the patient underwent therapeutic penetrating keratoplasty. Staphylococcal infection of the cornea may appear as a <span class="hlt">ring</span>-like infiltrate that is recalcitrant to medical management. PMID:23100354</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15148600','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15148600"><span>Drought responses of conifers in ecotone forests of northern Arizona: tree <span class="hlt">ring</span> <span class="hlt">growth</span> and leaf delta13C.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Adams, Henry D; Kolb, Thomas E</p> <p>2004-07-01</p> <p>We sought to understand differences in tree response to meteorological drought among species and soil types at two ecotone forests in northern Arizona, the pinyon-juniper woodland/ponderosa pine ecotone, and the higher elevation, wetter, ponderosa pine/mixed conifer ecotone. We used two approaches that provide different information about drought response: the ratio of standardized radial <span class="hlt">growth</span> in wet years to dry years (W:D) for the period between years 1950 and 2000 as a measure of <span class="hlt">growth</span> response to drought, and delta13C in leaves formed in non-drought (2001) and drought (2002) years as a measure of change in water use efficiency (WUE) in response to drought. W:D and leaf delta13C response to drought for Pinus edulis and P. ponderosa did not differ for trees growing on coarse-texture soils derived from cinders compared with finer textured soils derived from flow basalts or sedimentary rocks. P. ponderosa growing near its low elevation range limit at the pinyon-juniper woodland/ponderosa pine ecotone had a greater <span class="hlt">growth</span> response to drought (higher W:D) and a larger increase in WUE in response to drought than co-occurring P. edulis growing near its high elevation range limit. P. flexilis and Pseudotsuga menziesii growing near their low elevation range limit at the ponderosa pine/mixed conifer ecotone had a larger <span class="hlt">growth</span> response to drought than co-occurring P. ponderosa growing near its high elevation range limit. Increases in WUE in response to drought were similar for all species at the ponderosa pine/mixed conifer ecotone. Low elevation populations of P. ponderosa had greater <span class="hlt">growth</span> response to drought than high-elevation populations, whereas populations had a similar increase in WUE in response to drought. Our findings of different responses to drought among co-occurring tree species and between low- and high-elevation populations are interpreted in the context of drought impacts on montane coniferous forests of the southwestern USA.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EPSC....9..633S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EPSC....9..633S"><span>Propellers in Saturn's <span class="hlt">rings</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sremcevic, M.; Stewart, G. R.; Albers, N.; Esposito, L. W.</p> <p>2014-04-01</p> <p> detection in UVIS β Centauri Rev96 occultation at r=94,958km offers insight into the morphology of the discovered objects in B <span class="hlt">ring</span>. The feature is statistically significant, consists of 6 consequent high counts, and represents a gap with a <span class="hlt">width</span> of 300m. Similar to the Bleriot occultation in Persei Rev42, the B <span class="hlt">ring</span> β Centauri occultation also shows a very prominent gap and a single flanking higher density wake. The significance of the UVIS features was confirmed using statistical T-test. The result from UVIS occultation together with dozen feature detections in ISS NAC images demonstrates beyond reasonable doubt that the presented B <span class="hlt">ring</span> features are indeed propellers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA18278.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA18278.html"><span><span class="hlt">Ring</span> King</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2014-08-18</p> <p>Saturn reigns supreme, encircled by its retinue of <span class="hlt">rings</span>. Although all four giant planets have <span class="hlt">ring</span> systems, Saturn's is by far the most massive and impressive. Scientists are trying to understand why by studying how the <span class="hlt">rings</span> have formed and how they have evolved over time. Also seen in this image is Saturn's famous north polar vortex and hexagon. This view looks toward the sunlit side of the <span class="hlt">rings</span> from about 37 degrees above the ringplane. The image was taken with the Cassini spacecraft wide-angle camera on May 4, 2014 using a spectral filter which preferentially admits wavelengths of near-infrared light centered at 752 nanometers. The view was acquired at a distance of approximately 2 million miles (3 million kilometers) from Saturn. Image scale is 110 miles (180 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA18278</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..1412636E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..1412636E"><span>A season in Saturn's <span class="hlt">rings</span>: Cycling, recycling and <span class="hlt">ring</span> history</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Esposito, L. W.; Meinke, B. K.; Albers, N.; Sremcevic, M.</p> <p>2012-04-01</p> <p>: Self gravity causes wakes, viscosity, overstability and local aggregate <span class="hlt">growth</span>. Nearby moons and resonant forcing drive the <span class="hlt">ring</span> system away from equilibrium through streamline crowding, which allows enhanced accretional <span class="hlt">growth</span>. Structures form and disappear at length scales from meters to kilometers, on time scales of hours to months. This cyclic behavior resembles an ecological predator-prey system or a boom-and-bust economic cycle. In such an agitated stochastic system, solid bodies may represent the absorbing states of a Markov chain: rare events can produce a distibution with many transient but a few long-lasting bodies. These bodies would preferentially form at shepherded <span class="hlt">ring</span> edges near the Roche limit, as hypothesized by Charnoz. These large bodies can sequester material in their interiors, reducing the amount of meteoritic <span class="hlt">ring</span> pollution and recycling the <span class="hlt">ring</span> material into new <span class="hlt">rings</span>. Such processes would allow the <span class="hlt">rings</span> to be as ancient as the solar system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.P21E..07S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.P21E..07S"><span>Propellers in Saturn's <span class="hlt">rings</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sremcevic, M.; Stewart, G. R.; Albers, N.; Esposito, L. W.</p> <p>2013-12-01</p> <p> <span class="hlt">ring</span>. The gap moves at Kepler speed appropriate for its radial location. Radial offsets of the gap locations in UVIS occultations are consistent with an asymmetric propeller shape. The asymmetry of the observed shape is most likely a consequence of the strong surface mass density gradient, as the feature is located at an edge between high and relatively low optical depth. From the radial separation of the propeller wings we estimate that the embedded body is about 1.5km in size. In addition to the population of "big" propellers we found evidence for a population of much smaller propellers which are more similar to known A <span class="hlt">ring</span> propellers (size <500m). We have found one significant feature in beta Centauri Rev96 UVIS occultation at r=94,958km. The feature represents a gap with a <span class="hlt">width</span> of 300m. This gap is statistically significant and consists of 6 consequent high counts. All other UVIS occultations show a flat and boring profile at this location. The r=94,958km feature is very similar in shape and size to a known detection of A <span class="hlt">ring</span> propeller Bleriot from zeta Persei Rev42 occultation. This feature is also found as a dark spot moving at Kepler speed across several ISS images. Additionally we found 5 more small propeller candidates in ISS images of the inner B <span class="hlt">ring</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25345032','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25345032"><span>[Dendroclimatic potentials for the tree <span class="hlt">rings</span> of Huangshan pine (Pinus taiwanensis ) at Xiaolinhai in the western Dabie Mountains, China].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Peng, Jian-Feng; Li, Guo-Dong; Li, Ling-Ling</p> <p>2014-07-01</p> <p>By using the dendrochronology research methods, this paper developed the 1915-2011 tree <span class="hlt">ring-width</span> standard chronology of the Huangshan pine (Pinus taiwanesis) at the north slope of western Dabie Mountains in the junction of Hubei, Henan and Anhui provinces. High mean sensitivity (MS) indicated that there was conspicuous high-frequency climate signals and high first-order autocorrelation (AC) showed there were significant lag-effects of tree previous <span class="hlt">growth</span>. The higher signal-to-noise ratio (SNR) and expressed population signal (EPS) indicated that the trees had high levels of common climate signals. Correlations between the tree <span class="hlt">ring-width</span> standard chronology and climatic factors (1959-2011) revealed the significant influences of temperature, precipitation and relative humidity on the tree <span class="hlt">width</span> <span class="hlt">growth</span> of Huangshan pine by the end of growing season (September and October). Significant positive correlations were found between the tree-<span class="hlt">ring</span> indices and the Palmer drought severity index (PDSI) of current September and October. In conclusion, the combination of water and heat of September and October is the major effect factor for the <span class="hlt">growth</span> of Huangshan pine in western Dabie Mountains.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27301603','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27301603"><span>Vascular <span class="hlt">rings</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Backer, Carl L; Mongé, Michael C; Popescu, Andrada R; Eltayeb, Osama M; Rastatter, Jeffrey C; Rigsby, Cynthia K</p> <p>2016-06-01</p> <p>The term vascular <span class="hlt">ring</span> refers to congenital vascular anomalies of the aortic arch system that compress the esophagus and trachea, causing symptoms related to those two structures. The most common vascular <span class="hlt">rings</span> are double aortic arch and right aortic arch with left ligamentum. Pulmonary artery sling is rare and these patients need to be carefully evaluated for frequently associated tracheal stenosis. Another cause of tracheal compression occurring only in infants is the innominate artery compression syndrome. In the current era, the diagnosis of a vascular <span class="hlt">ring</span> is best established by CT imaging that can accurately delineate the anatomy of the vascular <span class="hlt">ring</span> and associated tracheal pathology. For patients with a right aortic arch there recently has been an increased recognition of a structure called a Kommerell diverticulum which may require resection and transfer of the left subclavian artery to the left carotid artery. A very rare vascular <span class="hlt">ring</span> is the circumflex aorta that is now treated with the aortic uncrossing operation. Patients with vascular <span class="hlt">rings</span> should all have an echocardiogram because of the incidence of associated congenital heart disease. We also recommend bronchoscopy to assess for additional tracheal pathology and provide an assessment of the degree of tracheomalacia and bronchomalacia. The outcomes of surgical intervention are excellent and most patients have complete resolution of symptoms over a period of time. Copyright © 2016 Elsevier Inc. All rights reserved.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AJ....154..144B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AJ....154..144B"><span>The Structure of Chariklo’s <span class="hlt">Rings</span> from Stellar Occultations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bérard, D.; Sicardy, B.; Camargo, J. I. B.; Desmars, J.; Braga-Ribas, F.; Ortiz, J.-L.; Duffard, R.; Morales, N.; Meza, E.; Leiva, R.; Benedetti-Rossi, G.; Vieira-Martins, R.; Gomes Júnior, A.-R.; Assafin, M.; Colas, F.; Dauvergne, J.-L.; Kervella, P.; Lecacheux, J.; Maquet, L.; Vachier, F.; Renner, S.; Monard, B.; Sickafoose, A. A.; Breytenbach, H.; Genade, A.; Beisker, W.; Bath, K.-L.; Bode, H.-J.; Backes, M.; Ivanov, V. D.; Jehin, E.; Gillon, M.; Manfroid, J.; Pollock, J.; Tancredi, G.; Roland, S.; Salvo, R.; Vanzi, L.; Herald, D.; Gault, D.; Kerr, S.; Pavlov, H.; Hill, K. M.; Bradshaw, J.; Barry, M. A.; Cool, A.; Lade, B.; Cole, A.; Broughton, J.; Newman, J.; Horvat, R.; Maybour, D.; Giles, D.; Davis, L.; Paton, R. A.; Loader, B.; Pennell, A.; Jaquiery, P.-D.; Brillant, S.; Selman, F.; Dumas, C.; Herrera, C.; Carraro, G.; Monaco, L.; Maury, A.; Peyrot, A.; Teng-Chuen-Yu, J.-P.; Richichi, A.; Irawati, P.; De Witt, C.; Schoenau, P.; Prager, R.; Colazo, C.; Melia, R.; Spagnotto, J.; Blain, A.; Alonso, S.; Román, A.; Santos-Sanz, P.; Rizos, J.-L.; Maestre, J.-L.; Dunham, D.</p> <p>2017-10-01</p> <p>Two narrow and dense <span class="hlt">rings</span> (called C1R and C2R) were discovered around the Centaur object (10199) Chariklo during a stellar occultation observed on 2013 June 3. Following this discovery, we planned observations of several occultations by Chariklo’s system in order to better characterize the physical properties of the <span class="hlt">ring</span> and main body. Here, we use 12 successful occulations by Chariklo observed between 2014 and 2016. They provide <span class="hlt">ring</span> profiles (physical <span class="hlt">width</span>, opacity, edge structure) and constraints on the radii and pole position. Our new observations are currently consistent with the circular <span class="hlt">ring</span> solution and pole position, to within the ±3.3 km formal uncertainty for the <span class="hlt">ring</span> radii derived by Braga-Ribas et al. The six resolved C1R profiles reveal significant <span class="hlt">width</span> variations from ∼5 to 7.5 km. The <span class="hlt">width</span> of the fainter <span class="hlt">ring</span> C2R is less constrained, and may vary between 0.1 and 1 km. The inner and outer edges of C1R are consistent with infinitely sharp boundaries, with typical upper limits of one kilometer for the transition zone between the <span class="hlt">ring</span> and empty space. No constraint on the sharpness of C2R’s edges is available. A 1σ upper limit of ∼20 m is derived for the equivalent <span class="hlt">width</span> of narrow (physical <span class="hlt">width</span> < 4 km) <span class="hlt">rings</span> up to distances of 12,000 km, counted in the <span class="hlt">ring</span> plane.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/35841','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/35841"><span>Basic tree-<span class="hlt">ring</span> sample preparation techniques for aging aspen</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Lance A. Asherin; Stephen A. Mata</p> <p>2001-01-01</p> <p>Aspen is notoriously difficult to age because of its light-colored wood and faint annual <span class="hlt">growth</span> <span class="hlt">rings</span>. Careful preparation and processing of aspen <span class="hlt">ring</span> samples can overcome these problems, yield accurate age and <span class="hlt">growth</span> estimates, and concisely date disturbance events present in the tree-<span class="hlt">ring</span> record. Proper collection of aspen wood is essential in obtaining usable <span class="hlt">ring</span>...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/wri/1978/0136/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/wri/1978/0136/report.pdf"><span>Tree <span class="hlt">rings</span> as indicators of hydrologic change in the Great Dismal Swamp, Virginia and North Carolina</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Phipps, Richard L.; Ierley, D.L.; Baker, C.P.</p> <p>1979-01-01</p> <p>Analysis of tree <span class="hlt">rings</span> of large, canopy loblolly pines (Pinus taeda L.) growing near a drainage ditch in the Great Dismal Swamp have indicated that the tree <span class="hlt">rings</span> are datable and hydrologically (climatically) sensitive. Climatic and prior <span class="hlt">growth</span> factors in regression explained 87 and 71 percent of the variance of the preditching and postditching earlywood <span class="hlt">widths</span>, respectively, and 82 and 70 percent of the latewood <span class="hlt">widths</span> for the same time periods. Early summer precipitation was significantly, and positively correlated with preditching latewood <span class="hlt">growth</span>. When preditching and postditching records were merged into a single record, regression analysis explained less <span class="hlt">growth</span> variation than when the two time periods were considered individually, implying a change in <span class="hlt">growth</span> response following ditching. Prior to ditching, <span class="hlt">growth</span> was most limited by dry summers which followed dry summers. After ditching, <span class="hlt">growth</span> was less strongly linked with precipitation and more strongly linked with temperature. Regression results are compatible with the contention that growing season water levels in the proximity of the collection site have been lower since ditching. (Kosco-USGS)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26086094','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26086094"><span>Arabidopsis <span class="hlt">RING</span> E3 ubiquitin ligase AtATL80 is negatively involved in phosphate mobilization and cold stress response in sufficient phosphate <span class="hlt">growth</span> conditions.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Suh, Ji Yeon; Kim, Woo Taek</p> <p>2015-08-07</p> <p>Phosphate (Pi) remobilization in plants is critical to continuous <span class="hlt">growth</span> and development. AtATL80 is a plasma membrane (PM)-localized <span class="hlt">RING</span> E3 ubiquitin (Ub) ligase that belongs to the Arabidopsis Tóxicos en Levadura (ATL) family. AtATL80 was upregulated by long-term low Pi (0-0.02 mM KH2PO4) conditions in Arabidopsis seedlings. AtATL80-overexpressing transgenic Arabidopsis plants (35S:AtATL80-sGFP) displayed increased phosphorus (P) accumulation in the shoots and lower biomass, as well as reduced P-utilization efficiency (PUE) under high Pi (1 mM KH2PO4) conditions compared to wild-type plants. The loss-of-function atatl80 mutant line exhibited opposite phenotypic traits. The atatl80 mutant line bolted earlier than wild-type plants, whereas AtATL80-overexpressors bloomed significantly later and produced lower seed yields than wild-type plants under high Pi conditions. Thus, AtATL80 is negatively correlated not only with P content and PUE, but also with biomass and seed yield in Arabidopsis. In addition, AtATL80-overexpressors were significantly more sensitive to cold stress than wild-type plants, while the atatl80 mutant line exhibited an increased tolerance to cold stress. Taken together, our results suggest that AtATL80, a PM-localized ATL-type <span class="hlt">RING</span> E3 Ub ligase, participates in the Pi mobilization and cold stress response as a negative factor in Arabidopsis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA10094.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA10094.html"><span>Saturn <span class="hlt">Ring</span></span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2007-12-12</p> <p>Like Earth, Saturn has an invisible <span class="hlt">ring</span> of energetic ions trapped in its magnetic field. This feature is known as a "<span class="hlt">ring</span> current." This <span class="hlt">ring</span> current has been imaged with a special camera on Cassini sensitive to energetic neutral atoms. This is a false color map of the intensity of the energetic neutral atoms emitted from the <span class="hlt">ring</span> current through a processed called charged exchange. In this process a trapped energetic ion steals and electron from cold gas atoms and becomes neutral and escapes the magnetic field. The Cassini Magnetospheric Imaging Instrument's ion and neutral camera records the intensity of the escaping particles, which provides a map of the <span class="hlt">ring</span> current. In this image, the colors represent the intensity of the neutral emission, which is a reflection of the trapped ions. This "<span class="hlt">ring</span>" is much farther from Saturn (roughly five times farther) than Saturn's famous icy <span class="hlt">rings</span>. Red in the image represents the higher intensity of the particles, while blue is less intense. Saturn's <span class="hlt">ring</span> current had not been mapped before on a global scale, only "snippets" or areas were mapped previously but not in this detail. This instrument allows scientists to produce movies (see PIA10083) that show how this <span class="hlt">ring</span> changes over time. These movies reveal a dynamic system, which is usually not as uniform as depicted in this image. The <span class="hlt">ring</span> current is doughnut shaped but in some instances it appears as if someone took a bite out of it. This image was obtained on March 19, 2007, at a latitude of about 54.5 degrees and radial distance 1.5 million kilometres (920,000 miles). Saturn is at the center, and the dotted circles represent the orbits of the moon's Rhea and Titan. The Z axis points parallel to Saturn's spin axis, the X axis points roughly sunward in the sun-spin axis plane, and the Y axis completes the system, pointing roughly toward dusk. The ion and neutral camera's field of view is marked by the white line and accounts for the cut-off of the image on the left. The</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4196189','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4196189"><span>X-linked inhibitor of apoptosis protein (XIAP) lacking <span class="hlt">RING</span> domain localizes to the nuclear and promotes cancer cell anchorage-independent <span class="hlt">growth</span> by targeting the E2F1/Cyclin E axis</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Cao, Zipeng; Li, Xueyong; Li, Jingxia; Luo, Wenjing; Huang, Chuanshu; Chen, Jingyuan</p> <p>2014-01-01</p> <p>The inhibitor of apoptosis protein XIAP (X-linked inhibitor of apoptosis protein) is a well-documented protein that is located in cytoplasm acting as a potent regulator of cell apoptosis. Here, we showed that expressing XIAP with <span class="hlt">RING</span> (Really Interesting New Gene) domain deletion (XIAPΔ<span class="hlt">RING</span>) in cancer cells promoted cancer cell anchorage-independent <span class="hlt">growth</span> and G1/S phase transition companied with increasing cyclin e transcription activity and protein expression. Further studies revealed that XIAPΔ<span class="hlt">RING</span> was mainly localized in nuclear with increased binding with E2F1, whereas XIAP with BIR (Baculoviral IAP Repeat) domains deletion (XIAPΔBIRs) was entirely presented in cytoplasma with losing its binding with E2F1, suggesting that <span class="hlt">RING</span> domain was able to inhibit BIR domains nuclear localization, by which impaired BIRs binding with E2F1 in cellular nucleus in intact cells. These studies identified a new function of XIAP protein in cellular nucleus is to regulate E2F1 transcriptional activity by binding with E2F1 in cancer cells. Our current finding of an effect of XIAPΔ<span class="hlt">RING</span> expression on cancer cell anchorage-independent <span class="hlt">growth</span> suggests that overexpression of this protein may contribute to genetic instability associated with cell cycle and checkpoint perturbations, in addition to its impact on cellular apoptosis. PMID:25216527</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12093736','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12093736"><span>Division site placement in E.coli: mutations that prevent formation of the MinE <span class="hlt">ring</span> lead to loss of the normal midcell arrest of <span class="hlt">growth</span> of polar MinD membrane domains.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shih, Yu-Ling; Fu, Xiaoli; King, Glenn F; Le, Trung; Rothfield, Lawrence</p> <p>2002-07-01</p> <p>The MinE protein functions as a topological specificity factor in determining the site of septal placement in Escherichia coli. MinE assembles into a membrane-associated <span class="hlt">ring</span> structure near midcell and directs the localization of MinD and MinC into a membrane- associated polar zone that undergoes a characteristic pole-to-pole oscillation cycle. Single (green fluorescent protein) and double label (yellow fluorescent protein/cyan fluorescent protein) fluorescence labeling experiments showed that mutational alteration of a site on the alpha-face of MinE led to a failure to assemble the MinE <span class="hlt">ring</span>, associated with loss of the ability to support a normal pattern of division site placement. The absence of the MinE <span class="hlt">ring</span> did not prevent the assembly and disassembly of the MinD polar zone. Mutant cells lacking the MinE <span class="hlt">ring</span> were characterized by the <span class="hlt">growth</span> of MinD polar zones past their normal arrest point near midcell. The results suggested that the MinE <span class="hlt">ring</span> acts as a stop-<span class="hlt">growth</span> mechanism to prevent the MinCD polar zone from extending beyond the midcell division site.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title7-vol2/pdf/CFR-2010-title7-vol2-sec29-1085.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title7-vol2/pdf/CFR-2010-title7-vol2-sec29-1085.pdf"><span>7 CFR 29.1085 - <span class="hlt">Width</span>.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-01-01</p> <p>.... <span class="hlt">Width</span>, as an element of quality, does not apply to tobacco in strip form. (See Elements of Quality Chart... Heavy Fleshy Medium Thin Oil Lean Oily Rich Color intensity Pale Weak Moderate Strong Deep. <span class="hlt">Width</span>... quality...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title7-vol2/pdf/CFR-2011-title7-vol2-sec29-1085.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title7-vol2/pdf/CFR-2011-title7-vol2-sec29-1085.pdf"><span>7 CFR 29.1085 - <span class="hlt">Width</span>.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-01-01</p> <p>.... <span class="hlt">Width</span>, as an element of quality, does not apply to tobacco in strip form. (See Elements of Quality Chart... Heavy Fleshy Medium Thin Oil Lean Oily Rich Color intensity Pale Weak Moderate Strong Deep. <span class="hlt">Width</span>... quality...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA07559&hterms=homepage&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dhomepage','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA07559&hterms=homepage&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dhomepage"><span>Luminescent <span class="hlt">Rings</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2005-01-01</p> <p><p/> This view shows the unlit face of Saturn's <span class="hlt">rings</span>, visible via scattered and transmitted light. In these views, dark regions represent gaps and areas of higher particle densities, while brighter regions are filled with less dense concentrations of <span class="hlt">ring</span> particles. <p/> The dim right side of the image contains nearly the entire C <span class="hlt">ring</span>. The brighter region in the middle is the inner B <span class="hlt">ring</span>, while the darkest part represents the dense outer B <span class="hlt">Ring</span>. The Cassini Division and the innermost part of the A <span class="hlt">ring</span> are at the upper-left. <p/> Saturn's shadow carves a dark triangle out of the lower right corner of this image. <p/> The image was taken in visible light with the Cassini spacecraft wide-angle camera on June 8, 2005, at a distance of approximately 433,000 kilometers (269,000 miles) from Saturn. The image scale is 22 kilometers (14 miles) per pixel. <p/> The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo. <p/> For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org .</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA557280','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA557280"><span>Cave <span class="hlt">Rings</span></span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2010-10-13</p> <p>hypothesis, that cave <span class="hlt">rings</span> are formed in the same manner as coffee <span class="hlt">rings</span>[3], that is, due to the enhanced deposition at the edges of sessile drops ...Literature The ‘splash ring’ conjecture is described in [5]. It is claimed that 45◦ is the most probable angle for secondary drops to be ejected at, and that...ring’ is the deposit formed when a sessile drop of a solution containing dissolved particles, such as coffee or salt, dries. This was investigated by</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AcO....80....8R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AcO....80....8R"><span>Long-term <span class="hlt">growth</span> decline in Toona ciliata in a moist tropical forest in Bangladesh: Impact of global warming</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rahman, Mizanur; Islam, Rofiqul; Islam, Mahmuda</p> <p>2017-04-01</p> <p>Tropical forests are carbon rich ecosystems and small changes in tropical forest tree <span class="hlt">growth</span> substantially influence the global carbon cycle. Forest monitoring studies report inconsistent <span class="hlt">growth</span> changes in tropical forest trees over the past decades. Most of the studies highlighted changes in the forest level carbon gain, neglecting the species-specific <span class="hlt">growth</span> changes which ultimately determine community-level responses. Tree-<span class="hlt">ring</span> analysis can provide historical data on species-specific tree <span class="hlt">growth</span> with annual resolution. Such studies are inadequate in Bangladesh, which is one of the most climate sensitive regions in the tropics. In this study, we investigated long-term <span class="hlt">growth</span> rates of Toona ciliata in a moist tropical forest of Bangladesh by using tree-<span class="hlt">ring</span> analysis. We sampled 50 trees of varying size, obtained increment cores from these trees and measured tree-<span class="hlt">ring</span> <span class="hlt">width</span>. Analyses of <span class="hlt">growth</span> patterns revealed size-dependent <span class="hlt">growth</span> increments. After correcting for the effect of tree size on tree <span class="hlt">growth</span> (ontogenetic changes) by two different methods we found declining <span class="hlt">growth</span> rates in T. ciliata from 1960 to 2013. Standardized <span class="hlt">ring-width</span> index (RWI) was strongly negatively correlated with annual mean and maximum temperatures suggesting that rising temperature might cause the observed <span class="hlt">growth</span> decline in T. ciliata. Assuming that global temperatures will rise at the current rate, the observed <span class="hlt">growth</span> decline is assumed to continue. The analysis of stable carbon and oxygen isotopes may reveal more insight on the physiological response of this species to future climatic changes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.2871W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.2871W"><span>From process to proxy: Ecological challenges and opportunities of tree-<span class="hlt">ring</span> based environmental reconstructions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wilmking, Martin; Buras, Allan; Heinrich, Ingo; Scharnweber, Tobias; Simard, Sonia; Smiljanic, Marko; van der Maaten, Ernst; van der Maaten-Theunissen, Marieke</p> <p>2014-05-01</p> <p>Trees are sessile, long-living organisms and as such constantly need to adapt to changing environmental conditions. Accordingly, they often show high phenotypic plasticity (the ability to change phenotypic traits, such as allocation of resources) in response to environmental change. This high phenotypic plasticity is generally considered as one of the main ingredients for a sessile organism to survive and reach high ages. Precisely because of the ability of trees to reach old age and their in-ability to simply run away when conditions get worse, <span class="hlt">growth</span> information recorded in tree <span class="hlt">rings</span> has long been used as a major environmental proxy, covering time scales from decades to millennia. Past environmental conditions (e.g. climate) are recorded in i.e. annual tree-<span class="hlt">ring</span> <span class="hlt">width</span>, early- and latewood <span class="hlt">width</span>, wood density, isotopic concentrations, cell anatomy or wood chemistry. One prerequisite for a reconstruction is that the relationship between the environmental variable influencing tree <span class="hlt">growth</span> and the tree-<span class="hlt">growth</span> variable itself is stable through time. This, however, might contrast the ecological theory of high plasticity and the trees ability to adapt to change. To untangle possible mechanisms leading to stable or unstable relationships between tree <span class="hlt">growth</span> and environmental variables, it is helpful to have exact site information and several proxy variables of each tree-<span class="hlt">ring</span> series available. Although we gain insight into the environmental history of a sampling site when sampling today, this is extremely difficult when using archeological wood. In this latter case, we face the additional challenge of unknown origin, provenance and (or) site conditions, making it even more important to use multiple proxy time-series from the same sample. Here, we review typical examples, where the relationship between tree <span class="hlt">growth</span> and environmental variables seems 1) stable and 2) instable through time, and relate these two cases to ecological theory. Based on ecological theory, we then</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1991Sci...253..995P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1991Sci...253..995P"><span>An explanation for Neptune's <span class="hlt">ring</span> arcs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Porco, Carolyn C.</p> <p>1991-08-01</p> <p>The Voyager mission revealed a complex system of <span class="hlt">rings</span> and <span class="hlt">ring</span> arcs around Neptune and uncovered six new satellites, four of which occupy orbits well inside the <span class="hlt">ring</span> region. Analysis of Voyager data shows that a radial distortion with an amplitude of approximately 30 kilometers is traveling through the <span class="hlt">ring</span> arcs, a perturbation attributable to the nearby satellite Galatea. Moreover, the arcs appear to be azimuthally confined by a resonant interaction with the same satellite, yielding a maximum spread in <span class="hlt">ring</span> particle semimajor axes of 0.6 kilometer and a spread in forced eccentricities large enough to explain the arc's 15-kilometer radial <span class="hlt">widths</span>. Additional <span class="hlt">ring</span> arcs discovered in the course of this study give further support to this model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19910065376&hterms=Galatea&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DGalatea','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19910065376&hterms=Galatea&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DGalatea"><span>An explanation for Neptune's <span class="hlt">ring</span> arcs</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Porco, Carolyn C.</p> <p>1991-01-01</p> <p>The Voyager mission revealed a complex system of <span class="hlt">rings</span> and <span class="hlt">ring</span> arcs around Neptune and uncovered six new satellites, four of which occupy orbits well inside the <span class="hlt">ring</span> region. Analysis of Voyager data shows that a radial distortion with an amplitude of approximately 30 kilometers is traveling through the <span class="hlt">ring</span> arcs, a perturbation attributable to the nearby satellite Galatea. Moreover, the arcs appear to be azimuthally confined by a resonant interaction with the same satellite, yielding a maximum spread in <span class="hlt">ring</span> particle semimajor axes of 0.6 kilometer and a spread in forced eccentricities large enough to explain the arc's 15-kilometer radial <span class="hlt">widths</span>. Additional <span class="hlt">ring</span> arcs discovered in the course of this study give further support to this model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17775342','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17775342"><span>An Explanation for Neptune's <span class="hlt">Ring</span> Arcs.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Porco, C C</p> <p>1991-08-30</p> <p>The Voyager mission revealed a complex system of <span class="hlt">rings</span> and <span class="hlt">ring</span> arcs around Neptune and uncovered six new satellites, four of which occupy orbits well inside the <span class="hlt">ring</span> region. Analysis of Voyager data shows that a radial distortion with an amplitude of approximately 30 kilometers is traveling through the <span class="hlt">ring</span> arcs, a perturbation attributable to the nearby satellite Galatea. Moreover, the arcs appear to be azimuthally confined by a resonant interaction with the same satellite, yielding a maximum spread in <span class="hlt">ring</span> particle semimajor axes of 0.6 kilometer and a spread in forced eccentricities large enough to explain the arcs' 15-kilometer radial <span class="hlt">widths</span>. Additional <span class="hlt">ring</span> arcs discovered in the course of this study give further support to this model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19820033629&hterms=american+mink&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Damerican%2Bmink','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19820033629&hterms=american+mink&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Damerican%2Bmink"><span>No evidence of <span class="hlt">rings</span> around Neptune</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Elliot, J. L.; Mink, D. J.; Baron, R. L.; Dunham, E.; Pingree, J. E.; French, R. G.; Elias, J. H.; Liller, W.; Nicholson, P. D.; Jones, T. J.</p> <p>1981-01-01</p> <p>The results of two observations of stellar occultations of Neptune to determine if the planet has a <span class="hlt">ring</span> system are reported. The sightings were made from Mt. Stromlo, Mauna Kea, and Cerro Tololo, noting that an equatorial <span class="hlt">ring</span> would subtend only two arcsec of view. An upper accretion limit was defined to set the region around Neptune where <span class="hlt">rings</span>, rather than satellites, could form. The intensities of the starlight from the two selected stars were recorded by photometers on magnetic tape during the occultation period. One of the stars did not occult, but passed through the entire region where a <span class="hlt">ring</span> system might be present. No definitive evidence for <span class="hlt">rings</span> was found, although an optical depth for a Neptunian <span class="hlt">ring</span> was calculated at 0.07, with a <span class="hlt">width</span> of more than 5 km and a radius of 31,400 km.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title14-vol3/pdf/CFR-2012-title14-vol3-sec121-115.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title14-vol3/pdf/CFR-2012-title14-vol3-sec121-115.pdf"><span>14 CFR 121.115 - Route <span class="hlt">width</span>.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-01-01</p> <p>... Route <span class="hlt">width</span>. (a) Routes and route segments over Federal airways, foreign airways, or advisory routes have a <span class="hlt">width</span> equal to the designated <span class="hlt">width</span> of those airways or advisory routes. Whenever the... clearance. (2) Minimum en route altitudes. (3) Ground and airborne navigation aids. (4) Air traffic density...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title14-vol3/pdf/CFR-2013-title14-vol3-sec121-115.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title14-vol3/pdf/CFR-2013-title14-vol3-sec121-115.pdf"><span>14 CFR 121.115 - Route <span class="hlt">width</span>.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-01-01</p> <p>... Route <span class="hlt">width</span>. (a) Routes and route segments over Federal airways, foreign airways, or advisory routes have a <span class="hlt">width</span> equal to the designated <span class="hlt">width</span> of those airways or advisory routes. Whenever the... clearance. (2) Minimum en route altitudes. (3) Ground and airborne navigation aids. (4) Air traffic density...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title14-vol3/pdf/CFR-2010-title14-vol3-sec121-115.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title14-vol3/pdf/CFR-2010-title14-vol3-sec121-115.pdf"><span>14 CFR 121.115 - Route <span class="hlt">width</span>.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-01-01</p> <p>... Route <span class="hlt">width</span>. (a) Routes and route segments over Federal airways, foreign airways, or advisory routes have a <span class="hlt">width</span> equal to the designated <span class="hlt">width</span> of those airways or advisory routes. Whenever the... clearance. (2) Minimum en route altitudes. (3) Ground and airborne navigation aids. (4) Air traffic density...</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title14-vol3/pdf/CFR-2014-title14-vol3-sec121-115.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title14-vol3/pdf/CFR-2014-title14-vol3-sec121-115.pdf"><span>14 CFR 121.115 - Route <span class="hlt">width</span>.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2014&page.go=Go">Code of Federal Regulations, 2014 CFR</a></p> <p></p> <p>2014-01-01</p> <p>... Route <span class="hlt">width</span>. (a) Routes and route segments over Federal airways, foreign airways, or advisory routes have a <span class="hlt">width</span> equal to the designated <span class="hlt">width</span> of those airways or advisory routes. Whenever the... clearance. (2) Minimum en route altitudes. (3) Ground and airborne navigation aids. (4) Air traffic density...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title14-vol3/pdf/CFR-2011-title14-vol3-sec121-115.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title14-vol3/pdf/CFR-2011-title14-vol3-sec121-115.pdf"><span>14 CFR 121.115 - Route <span class="hlt">width</span>.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-01-01</p> <p>... Route <span class="hlt">width</span>. (a) Routes and route segments over Federal airways, foreign airways, or advisory routes have a <span class="hlt">width</span> equal to the designated <span class="hlt">width</span> of those airways or advisory routes. Whenever the... clearance. (2) Minimum en route altitudes. (3) Ground and airborne navigation aids. (4) Air traffic density...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title23-vol1/pdf/CFR-2012-title23-vol1-sec658-15.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title23-vol1/pdf/CFR-2012-title23-vol1-sec658-15.pdf"><span>23 CFR 658.15 - <span class="hlt">Width</span>.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-04-01</p> <p>... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS TRUCK SIZE AND WEIGHT, ROUTE DESIGNATIONS-LENGTH, <span class="hlt">WIDTH</span> AND WEIGHT LIMITATIONS § 658.15 <span class="hlt">Width</span>. (a) No State shall impose a <span class="hlt">width</span> limitation of more or less than 102 inches, or its approximate metric equivalent, 2.6 meters (102.36 inches) on...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMPP33A2097A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMPP33A2097A"><span>A 7500-year record of plant physiology as palaeoenvironmental proxy from tree-<span class="hlt">ring</span> δ13C and <span class="hlt">growth</span> rates - the CARATE project</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Arppe, L.; Helama, S.; Mielikäinen, K.; Oinonen, M.; Timonen, M.</p> <p>2012-12-01</p> <p>This contribution presents a recently launched 4-year research project, "CARATE", aiming to produce new climatic and plant physiological records at high temporal resolution by the synthesis of annually/decadally resolved tree-<span class="hlt">ring</span> archives of <span class="hlt">growth</span>-rates and cellulose δ13C values from high-latitude continental Europe. The project mainly relies on a supra-long pinewood chronology from Finnish Lapland covering the mid and late Holocene times continuously through the millennia since 5634 B.C. until the present-day (Eronen et al. 2002, Helama et al. 2008). The chronology provides a highly sensitive, absolutely dated proxy record of past environment and climate variability at highest possible resolution that can be calibrated directly with instrumental records of environmental variables. While <span class="hlt">growth</span> rate records are invaluable tools for paleoclimate research at high frequencies, tree-<span class="hlt">ring</span> δ13C compositions have the potential to portray the high-to-low-frequency climate signals per se, without complications from time-series analysis. By combining isotope and <span class="hlt">growth</span> rate information, we aim to reconstruct regional high- and low-frequency climate variability over the past 7500 years with increased reliability, and explore the climate forcings behind the observed variations. The project was started by studying the strength of the common climatic signal both within- and between-sites, and possible associations to tree-physiological parameters. For this purpose, a set of 70 living pine trees (Pinus sylvestris) , growing in proximity of the subfossil pinewood collection sites in western and eastern Lapland, were cored for analysis of <span class="hlt">growth</span> rates and δ13C values. α-cellulose was extracted from decadal samples corresponding to the time period 1970-2010 including both early- and latewood. The δ13C time series show a consistent response to regional environmental forcing over the entire study area, with no discernable differences between western and eastern Lapland. Within</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23504983','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23504983"><span><span class="hlt">Growth</span> decline and divergent tree <span class="hlt">ring</span> isotopic composition (δ(13) C and δ(18) O) contradict predictions of CO2 stimulation in high altitudinal forests.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gómez-Guerrero, Armando; Silva, Lucas C R; Barrera-Reyes, Miguel; Kishchuk, Barbara; Velázquez-Martínez, Alejandro; Martínez-Trinidad, Tomás; Plascencia-Escalante, Francisca Ofelia; Horwath, William R</p> <p>2013-06-01</p> <p>Human-induced changes in atmospheric composition are expected to affect primary productivity across terrestrial biomes. Recent changes in productivity have been observed in many forest ecosystems, but low-latitude upper tree line forests remain to be investigated. Here, we use dendrochronological methods and isotopic analysis to examine changes in productivity, and their physiological basis, in Abies religiosa (Ar) and Pinus hartwegii (Ph) trees growing in high-elevation forests of central Mexico. Six sites were selected across a longitudinal transect (Transverse Volcanic Axis), from the Pacific Ocean toward the Gulf of Mexico, where mature dominant trees were sampled at altitudes ranging from 3200 to 4000 m asl. A total of 60 Ar and 84 Ph trees were analyzed to describe changes in <span class="hlt">growth</span> (annual-resolution) and isotopic composition (decadal-resolution) since the early 1900s. Our results show an initial widespread increase in basal area increment (BAI) during the first half of the past century. However, BAI has decreased significantly since the 1950s with accentuated decline after the 1980s in both species and across sites. We found a consistent reduction in atmosphere to wood (13) C discrimination, resulting from increasing water use efficiency (20-60%), coinciding with rising atmospheric CO2 . Changes in (13) C discrimination were not followed, however, by shifts in tree <span class="hlt">ring</span> δ(18) O, indicating site- and species-specific differences in water source or uptake strategy. Our results indicate that CO2 stimulation has not been enough to counteract warming-induced drought stress, but other stressors, such as progressive nutrient limitation, could also have contributed to <span class="hlt">growth</span> decline. Future studies should explore the distinct role of resource limitation (water vs. nutrients) in modulating the response of high-elevation ecosystems to atmospheric change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMPP13B1389F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMPP13B1389F"><span>Stable isotopic and chemical indicators of volcanic eruptions in tree <span class="hlt">rings</span> from Paricutin, Mexico</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>France, C.; Sheppard, P. R.; Jimenez Cano, N.; Speakman, R. J.</p> <p>2009-12-01</p> <p>Annual <span class="hlt">growth</span> <span class="hlt">rings</span> obtained from well dated tree <span class="hlt">ring</span> cores from Paricutin, Mexico are examined for unique chemical signatures that reflect a known local volcanic eruption and its subsequent atmospheric and terrestrial inputs. Stable carbon isotopic profiles are combined with elemental analyses to construct a chemical profile before, during, and after the known eruptive years (1943-1952) when a cinder cone formed near the town of Paricutin. Data from this well documented eruption are combined with controls obtained from outside the ash fall zone. Carbon isotopes exhibit an enriched spike (~3‰) during the eruptive period followed by a subsequent return to baseline values. This in combination with other stable isotopic indicators and increases in phosphorus, sulfur, and possibly other elements, suggest a unique set of chemical inputs from the eruption. The analytical approach developed here potentially can be used to date unknown eruptions which in the past have often relied on the common dendrochronologic technique of tree <span class="hlt">ring</span> <span class="hlt">width</span> determination, or on historic human records. The former method can be somewhat subjective as changes in <span class="hlt">ring</span> <span class="hlt">width</span> can be attributed to multiple causes in addition to volcanically induced environmental stresses; the latter method is restricted to eruptions occurring in the last few thousand years. The quantitative approach of chemical analyses presented in this study can now be combined with standard 14C dating to precisely date eruption events and place them in an anthropologic context.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014GPC...122..140C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014GPC...122..140C"><span>A cluster of stratospheric volcanic eruptions in the AD 530s recorded in Siberian tree <span class="hlt">rings</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Churakova (Sidorova), Olga V.; Bryukhanova, Marina V.; Saurer, Matthias; Boettger, Tatjana; Naurzbaev, Mukhtar M.; Myglan, Vladimir S.; Vaganov, Eugene A.; Hughes, Malcolm K.; Siegwolf, Rolf T. W.</p> <p>2014-11-01</p> <p>Recently published, improved chronologies for volcanic sulfate in Greenland and Antarctic ice permit a comparison of the <span class="hlt">growth</span> responses of absolutely annually dated tree <span class="hlt">rings</span> at three locations in Siberia with annual ice-core records of volcanic eruptions centered on AD 536. For the first time for this region and period, we present unique data sets for tree-<span class="hlt">ring</span> <span class="hlt">width</span>, cell-wall thickness, δ13C and δ18O in cellulose. These were based on multiple samples from relict wood of larch obtained from two sites close to the northern limit of tree <span class="hlt">growth</span> on the Taimyr Peninsula and in northeastern Yakutia, and at a high-elevation, location 20° further South in the Altai Mts. An event in AD 536 was associated with different, but marked, changes in tree-<span class="hlt">ring</span> parameters at the high-latitude sites compared with the high elevation site. An AD 541 event was associated with its own distinctive tree-<span class="hlt">ring</span> responses across the three sites and multiple variables. The years after AD 532 were marked by a strong and sustained decrease in <span class="hlt">growth</span> at the high-elevation, more southerly, site. The combination of improved ice-core chronology for the climatically effective volcanic eruptions of this part of the 6th century AD, and an array of tree-<span class="hlt">ring</span> sites with different climates and multiple tree-<span class="hlt">ring</span> variables permits a richer description of tree responses to this cluster of events. The pattern of tree-<span class="hlt">ring</span> parameter responses at the three locations in AD 536, AD 541, and perhaps AD 532 is consistent with responses to climatically effective volcanic eruptions influencing tree response in those and subsequent years.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSM41F2550C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSM41F2550C"><span>Predicting EMIC wave properties from <span class="hlt">ring</span> current plasma conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cowee, M.; Fu, X.; Jordanova, V.</p> <p>2015-12-01</p> <p>Recently, sophisticated computer models have shown that accurate, dynamic modelling of the energetic electrons in the radiation belt requires global and real-time plasma and wave conditions. Data provided by in-situ spacecraft measurement are too sparse to supply enough inputs for continuous global modeling of the radiation belt. Here we present a model to predict amplitude, peak frequency and spectral <span class="hlt">width</span> of the electromagnetic ion cyclotron (EMIC) wave from the anisotropic <span class="hlt">ring</span> current ion distributions, which are the source of the wave. The model is derived from hybrid simulations in a large initial parameter space for plasmas consisting of electrons, protons, and helium ions. Key parameters include the ratio of plasma frequency to ion gyrofrequency, the density, temperature and anisotropy of hot ions, and the cold-ion composition. The results show that amplitude, peak frequency and spectral <span class="hlt">width</span> of EMIC waves can be related to linear properties of the anisotropy-driven instability, e.g. <span class="hlt">growth</span> rate and plasma beta, through simple analytic formulas. Combined with a dynamic <span class="hlt">ring</span> current model, this model can provide global EMIC wave information needed for radiation-belt modeling.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/960972','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/960972"><span>Fjords in viscous fingering: selection of <span class="hlt">width</span> and opening scale</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Mineev-weinstein, Mark; Ristroph, Leif; Thrasher, Matthew; Swinney, Harry</p> <p>2008-01-01</p> <p>Our experiments on viscous fingering of air into oil contained between closely spaced plates reveal two selection rules for the fjords of oil that separate fingers of air. (Fjords are the building blocks of solutions of the zero-surface-tension Laplacian <span class="hlt">growth</span> equation.) Experiments in rectangular and circular geometries yield fjords with base <span class="hlt">widths</span> {lambda}{sub c}/2, where {lambda}{sub c} is the most unstable wavelength from a linear stability analysis. Further, fjords open at an angle of 8.0{sup o}{+-}1.0{sup o}. These selection rules hold for a wide range of pumping rates and fjord lengths, <span class="hlt">widths</span>, and directions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3836801','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3836801"><span>Genetic and Functional Studies Implicate Synaptic Overgrowth and <span class="hlt">Ring</span> Gland cAMP/PKA Signaling Defects in the Drosophila melanogaster Neurofibromatosis-1 <span class="hlt">Growth</span> Deficiency</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Walker, James A.; Gouzi, Jean Y.; Long, Jennifer B.; Huang, Sidong; Maher, Robert C.; Xia, Hongjing; Khalil, Kheyal; Ray, Arjun; Van Vactor, David; Bernards, René; Bernards, André</p> <p>2013-01-01</p> <p>Neurofibromatosis type 1 (NF1), a genetic disease that affects 1 in 3,000, is caused by loss of a large evolutionary conserved protein that serves as a GTPase Activating Protein (GAP) for Ras. Among Drosophila melanogaster Nf1 (dNf1) null mutant phenotypes, learning/memory deficits and reduced overall <span class="hlt">growth</span> resemble human NF1 symptoms. These and other dNf1 defects are relatively insensitive to manipulations that reduce Ras signaling strength but are suppressed by increasing signaling through the 3′-5′ cyclic adenosine monophosphate (cAMP) dependent Protein Kinase A (PKA) pathway, or phenocopied by inhibiting this pathway. However, whether dNf1 affects cAMP/PKA signaling directly or indirectly remains controversial. To shed light on this issue we screened 486 1st and 2nd chromosome deficiencies that uncover >80% of annotated genes for dominant modifiers of the dNf1 pupal size defect, identifying responsible genes in crosses with mutant alleles or by tissue-specific RNA interference (RNAi) knockdown. Validating the screen, identified suppressors include the previously implicated dAlk tyrosine kinase, its activating ligand jelly belly (jeb), two other genes involved in Ras/ERK signal transduction and several involved in cAMP/PKA signaling. Novel modifiers that implicate synaptic defects in the dNf1 <span class="hlt">growth</span> deficiency include the intersectin-related synaptic scaffold protein Dap160 and the cholecystokinin receptor-related CCKLR-17D1 drosulfakinin receptor. Providing mechanistic clues, we show that dAlk, jeb and CCKLR-17D1 are among mutants that also suppress a recently identified dNf1 neuromuscular junction (NMJ) overgrowth phenotype and that manipulations that increase cAMP/PKA signaling in adipokinetic hormone (AKH)-producing cells at the base of the neuroendocrine <span class="hlt">ring</span> gland restore the dNf1 <span class="hlt">growth</span> deficiency. Finally, supporting our previous contention that ALK might be a therapeutic target in NF1, we report that human ALK is expressed in cells that give rise</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/181935','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/181935"><span>Drought frequency in central California since 101 B.C. recordered in giant sequoia tree <span class="hlt">rings</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hughes, M.K.; Brown, P.M.</p> <p>1992-01-01</p> <p>Well replicated tree-<span class="hlt">ring</span> <span class="hlt">width</span> index chronologies have been developed for giant sequoia at three sites in the Sierra Nevada, California. Extreme low-<span class="hlt">growth</span> events in these chronologies correspond with regional drought events in the twentieth century in the San Joaquin drainage, in which the giant sequoia sites are located. This relationship is based upon comparison of tree-<span class="hlt">ring</span> indices with August Palmer Drought Severity Indices for California Climate Division 5. <span class="hlt">Ring-width</span> indices in the lowest decile from each site were compared. The frequency of low-<span class="hlt">growth</span> events which occurred at all three sites in the same year is reconstructed from 101 B.C. to A.D. 1988. The inferred frequency of severe drought events changes through time, sometimes suddenly. The period from roughly 1850 to 1950 had one of the lowest frequencies of drought of any one hundred year period in the 2089 year record. The twentieth century so far has had a below-average frequency of extreme droughts. 26 refs., 6 figs., 1 tab.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMGC24B..03T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMGC24B..03T"><span>Stable carbon isotopes and drought signal in the tree-<span class="hlt">rings</span> of northern white-cedar trees from boreal central Canada. (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tardif, J. C.; Au, R.</p> <p>2010-12-01</p> <p> both radial <span class="hlt">growth</span> and carbon assimilation, particularly during the month of June in the current growing season. During this month, the <span class="hlt">ring-width</span> index was sensitive to moisture stress (positive and negative association with precipitation and temperature, respectively) whereas the δ13C index showed enrichment with increasing temperature and drought index. Our results also suggested that in T. occidentalis <span class="hlt">ring</span> <span class="hlt">width</span> was more responsive to prolonged drought than δ13C since periods of decreased radial <span class="hlt">growth</span> most often coincided with documented drought intervals. Past experimental studies had indicated that young T. occidentalis trees may adjust stomatal conductance following exposure to water deficit suggesting that trees could develop a tolerance to subsequent water deficit. We speculate that in periods of extended drought, the absence of sustained year-to-year enriched δ13C values in T. occidentalis trees may thus reflect stomatal conditioning. This suggests that tree-<span class="hlt">ring</span> δ13C in T. occidentalis trees may have limited utility in drought reconstruction. Comparing the T. occidentalis δ13C data with that of other coniferous species from northern Manitoba revealed that T. occidentalis was the most δ13C-enriched species and that it portrayed the lowest δ13C sensitivity. Low correlations also were observed between species chronologies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFMGC21A0724S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFMGC21A0724S"><span>A Drought History Over The Northeastern Qinghai-Tibet Plateau Derived From Tree <span class="hlt">Rings</span> And Its Relation To Solar Activities</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shao, X.; Yin, Z.; Liang, E.; Xu, Y.; Zhu, H.</p> <p>2008-12-01</p> <p>We developed a tree-<span class="hlt">ring</span> <span class="hlt">width</span> chronology of Qilian juniper (Sabina przewalskii Kom.) from the northeastern Qaidam Basin of the northeastern Qinghai-Tibetan Plateau, which extends from 1580 BC to AD 2005 lasting 3585 years. It is composed of archaeological wood samples from 13 sites near Delingha, living trees growing at a site with relatively good moisture condition and other long living trees from multiple sites in the study area. Good cross-dating results among the <span class="hlt">ring-width</span> series from sites up to 100 km apart and the results of Kolmogorov-Smirnov two-sample test suggest that the archaeological wood and long living tree <span class="hlt">ring-width</span> series originated from the same probability distributions, which support the combination of these two types of samples into a single regional composite chronology. We find that the <span class="hlt">ring</span> <span class="hlt">widths</span> of the archaeological wood have statistical characteristics that are more similar to the samples from the site with relatively good moisture condition than those from the more arid sites. We also find that the moisture regime during the months before and at the onset of the growing season is the primary control on tree <span class="hlt">growth</span> in the study area. Therefore, the variation of <span class="hlt">ring</span> <span class="hlt">widths</span> in the archaeological wood can be used to infer the variation of moisture condition in the past. The composite chronology is used to reconstruct a drought index which is calculated as the difference between potential and actual evapotransporation of a water balance model. The variance explained in the calibration period (A.D. 1957-2001) is up to 65%. Verification results suggest that the reconstructed drought index can correctly represent the moisture condition for the study region. We examine the temporal variation pattern of the drought occurrence during the entire reconstruction period and found considerable variations of moisture condition at the interdecadal to centennial timescales. Spectral analysis of the reconstruction indicated significant peaks at</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23587837','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23587837"><span>Structure-activity relationships of hybrid annonaceous acetogenins: powerful <span class="hlt">growth</span> inhibitory effects of their connecting groups between heterocycle and hydrophobic carbon chain bearing THF <span class="hlt">ring</span> on human cancer cell lines.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kojima, Naoto; Fushimi, Tetsuya; Tatsukawa, Takahiro; Yoshimitsu, Takehiko; Tanaka, Tetsuaki; Yamori, Takao; Dan, Shingo; Iwasaki, Hiroki; Yamashita, Masayuki</p> <p>2013-05-01</p> <p>Five novel hybrid molecules of annonaceous acetogenins and insecticides targeting mitochondrial complex I were synthesized and their <span class="hlt">growth</span> inhibitory activities against 39 human cancer cell lines were investigated. It was revealed that the connecting group between the N-methylpyrazole part and the hydrophobic alkyl chain bearing the THF <span class="hlt">ring</span> influenced their biological activities significantly. Amide-connected analog 2, in particular, showed selective and very potent activity (<10 nM) against some cancer cell lines.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70168360','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70168360"><span>Reconstruction of late Holocene climate based on tree <span class="hlt">growth</span> and mechanistic hierarchical models</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Tipton, John; Hooten, Mevin B.; Pederson, Neil; Tingley, Martin; Bishop, Daniel</p> <p>2016-01-01</p> <p>Reconstruction of pre-instrumental, late Holocene climate is important for understanding how climate has changed in the past and how climate might change in the future. Statistical prediction of paleoclimate from tree <span class="hlt">ring</span> <span class="hlt">widths</span> is challenging because tree <span class="hlt">ring</span> <span class="hlt">widths</span> are a one-dimensional summary of annual <span class="hlt">growth</span> that represents a multi-dimensional set of climatic and biotic influences. We develop a Bayesian hierarchical framework using a nonlinear, biologically motivated tree <span class="hlt">ring</span> <span class="hlt">growth</span> model to jointly reconstruct temperature and precipitation in the Hudson Valley, New York. Using a common <span class="hlt">growth</span> function to describe the response of a tree to climate, we allow for species-specific parameterizations of the <span class="hlt">growth</span> response. To enable predictive backcasts, we model the climate variables with a vector autoregressive process on an annual timescale coupled with a multivariate conditional autoregressive process that accounts for temporal correlation and cross-correlation between temperature and precipitation on a monthly scale. Our multi-scale temporal model allows for flexibility in the climate response through time at different temporal scales and predicts reasonable climate scenarios given tree <span class="hlt">ring</span> <span class="hlt">width</span> data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4239536','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4239536"><span>Red cell distribution <span class="hlt">width</span> and nonalcoholic steatohepatitis</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Gulcan Kurt, Yasemin; Cayci, Tuncer; Aydin, Fevzi Nuri; Agilli, Mehmet</p> <p>2014-01-01</p> <p>Red cell distribution <span class="hlt">width</span> is a measure of deviation of the volume of red blood cells. It is a marker of anisocytosis and often used to evaluate the possible causes of anemia. Elevated red cell distribution <span class="hlt">width</span> levels are also associated with acute and chronic inflammatory responses. In nonalcoholic steatohepatitis, inflammation is accompanied with steatosis. For assuming red cell distribution <span class="hlt">width</span> as a marker of nonalcoholic steatohepatitis, intervening factors such as levels of inflammatory markers should also be evaluated. PMID:25473202</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5271640','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5271640"><span>Verification of metric theory of gravitation using beam <span class="hlt">width</span> correction for Sagnac effect</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Tan Weihan; Song Xiaojue; Gu Zhichong</p> <p>1983-10-01</p> <p>The effect of finite beam <span class="hlt">width</span> on the Sagnac frequency shift has been calculated by Zhbairy and Scully. However, their analysis is somewhat incorrect. In the present paper, we point out the questions included in their article and give a new analysis on this subject and the corrected equations for Sagnac effect for square <span class="hlt">ring</span> lasers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28075017','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28075017"><span>Intrapopulation variability in the timing of ontogenetic habitat shifts in sea turtles revealed using δ(15) N values from bone <span class="hlt">growth</span> <span class="hlt">rings</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Turner Tomaszewicz, Calandra N; Seminoff, Jeffrey A; Peckham, S Hoyt; Avens, Larisa; Kurle, Carolyn M</p> <p>2017-05-01</p> <p>Determining location and timing of ontogenetic shifts in the habitat use of highly migratory species, along with possible intrapopulation variation in these shifts, is essential for understanding mechanisms driving alternate life histories and assessing overall population trends. Measuring variations in multi-year habitat-use patterns is especially difficult for remote oceanic species. To investigate the potential for differential habitat use among migratory marine vertebrates, we measured the naturally occurring stable nitrogen isotope (δ(15) N) patterns that differentiate distinct ocean regions to create a 'regional isotope characterization', analysed the δ(15) N values from annual bone <span class="hlt">growth</span> layer <span class="hlt">rings</span> from dead-stranded animals, and then combined the bone and regional isotope data to track individual animal movement patterns over multiple years. We used humeri from juvenile North Pacific loggerhead turtles (Caretta caretta), animals that undergo long migrations across the North Pacific Ocean (NPO), using multiple discrete regions as they develop to adulthood. Typical of many migratory marine species, ontogenetic changes in habitat use throughout their decades-long juvenile stage is poorly understood, but each potential habitat has unique foraging opportunities and spatially explicit natural and anthropogenic threats that could affect key life-history parameters. We found a bimodal size/age distribution in the timing that juveniles underwent an ontogenetic habitat shift from the oceanic central North Pacific (CNP) to the neritic east Pacific region near the Baja California Peninsula (BCP) (42·7 ± 7·2 vs. 68·3 ± 3·4 cm carapace length, 7·5 ± 2·7 vs. 15·6 ± 1·7 years). Important to the survival of this population, these disparate habitats differ considerably in their food availability, energy requirements and threats, and these differences can influence life-history parameters such as <span class="hlt">growth</span>, survival and future fecundity. This is the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ERL....12h4008C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ERL....12h4008C"><span>Tree <span class="hlt">growth</span> and vegetation activity at the ecosystem-scale in the eastern Mediterranean</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Coulthard, Bethany L.; Touchan, Ramzi; Anchukaitis, Kevin J.; Meko, David M.; Sivrikaya, Fatih</p> <p>2017-08-01</p> <p>Linking annual tree <span class="hlt">growth</span> with remotely-sensed terrestrial vegetation indices provides a basis for using tree <span class="hlt">rings</span> as proxies for ecosystem primary productivity over large spatial and long temporal scales. In contrast with most previous tree <span class="hlt">ring</span>/remote sensing studies that have focused on temperature-limited boreal and taiga environments, here we compare the normalized difference vegetation index (NDVI) with a network of Pinus brutia tree <span class="hlt">ring</span> <span class="hlt">width</span> chronologies collected along ecological gradients in semiarid Cyprus, where both radial tree <span class="hlt">growth</span> and broader vegetation activity are controlled by drought. We find that the interaction between precipitation, elevation, and land-cover type generate a relationship between radial tree <span class="hlt">growth</span> and NDVI. While tree <span class="hlt">ring</span> chronologies at higher-elevation forested sites do not exhibit climate-driven linkages with NDVI, chronologies at lower-elevation dry sites are strongly correlated with NDVI during the winter precipitation season. At lower-elevation sites, land cover is dominated by grasslands and shrublands and tree <span class="hlt">ring</span> <span class="hlt">widths</span> operate as a proxy for ecosystem-scale vegetation activity. Tree <span class="hlt">rings</span> can therefore be used to reconstruct productivity in water-limited grasslands and shrublands, where future drought stress is expected to alter the global carbon cycle, biodiversity, and ecosystem functioning in the 21st century.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMEP53D..04E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMEP53D..04E"><span>The role of relative floodplain <span class="hlt">width</span> in forming anabranching rivers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Edmonds, D. A.; Polanco, S. E. M.; Amos, K.</p> <p>2015-12-01</p> <p>Anabranching rivers (including anastomosing) are a relatively common channel pattern, especially among the world's biggest rivers, and are defined as a system of multiple channels separated by immobile alluvial islands. The origin of anabranching remains poorly understood and is an important topic of research. Previous studies on Australian rivers and a recent empirical compilation show that floodplain <span class="hlt">width</span> (relative to the size of the channel) might play an important role in the formation of anabranching rivers. To test this idea further we carried out two sets of morphodynamic simulations using Delft3D. In the first set we create a generic channel-floodplain complex with uniform floodplain and channel <span class="hlt">width</span>, slope, and grain size and allow the system to adjust to passing floodwaves. In successive runs we hold all variables constant, except we increase floodplain <span class="hlt">width</span>. Results of these simulations show a transition from single channel to braided to anabranching as floodplain <span class="hlt">width</span> increases. Anabranching arises because as floodplain <span class="hlt">width</span> increases, alluvial bar <span class="hlt">growth</span> occurs on the floodplain. The emergence of bars causes flow bifurcation, and subsequent bifurcation instability leads to reduction of channels and the emergence of multiple anabranches. Transition to a stable anabranching pattern is achieved because as anabranches increase their cross-sectional area, Shields stresses on the intervening bars are reduced until they bars stop migrating. To test the idea that alluvial bar <span class="hlt">growth</span> can be a precursor to anabranching we carried out a second experiment set using boundary conditions from four different field scale anabranching rivers. Results from these simulations show that anabranching can initiate from alluvial bar <span class="hlt">growth</span>. Compared to field measurements of anabranching rivers our simulations accurately predict number of channels, supporting the idea that relatively wide floodplains might be an important attribute of anabranching rivers.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMPP13B1388C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMPP13B1388C"><span>Paleoclimate from Tree <span class="hlt">Rings</span> of Picea morrisonicola in Ta-Ta-Chia Area of Central Taiwan</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, T.; Wright, W. E.; Wei, K.; Cook, E. R.</p> <p>2009-12-01</p> <p>Almost no dendrochronology has been reported internationally from Taiwan, despite the existence of many dendrochronologically appropriate tree species. In this study, we reconstruct the regional paleoclimate using a multi-century tree <span class="hlt">ring-width</span> chronology developed from Picea morrisonicola ( the endemic Taiwan Spruce), a subtropical species growing in the Ta-Ta-Chia subalpine mountain areas of central Taiwan. Picea morrisonicola in Taiwan is the only member of the Picea genus whose distribution crosses the Tropic of Cancer. Statistical analysis of the climate signal demonstrates that both the temperature and precipitation have significant effects on tree <span class="hlt">growth</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1914285P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1914285P"><span>How to make a tree <span class="hlt">ring</span>: Coupling stem water flow and cambial activity in mature Alpine conifers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Peters, Richard L.; Frank, David C.; Treydte, Kerstin; Steppe, Kathy; Kahmen, Ansgar; Fonti, Patrick</p> <p>2017-04-01</p> <p>Inter-annual tree-<span class="hlt">ring</span> measurements are used to understand tree-<span class="hlt">growth</span> responses to climatic variability and reconstruct past climate conditions. In parallel, mechanistic models use experimentally defined plant-atmosphere interactions to explain past <span class="hlt">growth</span> responses and predict future environmental impact on forest productivity. Yet, substantial inconsistencies within mechanistic model ensembles and mismatches with empirical data indicate that significant progress is still needed to understand the processes occurring at an intra-annual resolution that drive annual <span class="hlt">growth</span>. However, challenges arise due to i) few datasets describing climatic responses of high-resolution physiological processes over longer time-scales, ii) uncertainties on the main mechanistic process limiting radial stem <span class="hlt">growth</span> and iii) complex interactions between multiple environmental factors which obscure detection of the main stem <span class="hlt">growth</span> driver, generating a gap between our understanding of intra- and inter-annual <span class="hlt">growth</span> mechanisms. We attempt to bridge the gap between inter-annual tree-<span class="hlt">ring</span> <span class="hlt">width</span> and sub-daily radial stem-<span class="hlt">growth</span> and provide a mechanistic perspective on how environmental conditions affect physiological processes that shape tree <span class="hlt">rings</span> in conifers. We combine sub-hourly sap flow and point dendrometer measurements performed on mature Alpine conifers (Larix decidua) into an individual-based mechanistic tree-<span class="hlt">growth</span> model to simulate sub-hourly cambial activity. The monitored trees are located along a high elevational transect in the Swiss Alps (Lötschental) to analyse the effect of increasing temperature. The model quantifies internal tree hydraulic pathways that regulate the turgidity within the cambial zone and induce cell enlargement for radial <span class="hlt">growth</span>. The simulations are validated against intra-annual <span class="hlt">growth</span> patterns derived from xylogenesis data and anatomical analyses. Our efforts advance the process-based understanding of how climate shapes the annual tree-<span class="hlt">ring</span> structures</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/20709553','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/20709553"><span><span class="hlt">Ringing</span> wormholes</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Konoplya, R.A.; Molina, C.</p> <p>2005-06-15</p> <p>We investigate the response of traversable wormholes to external perturbations through finding their characteristic frequencies and time-domain profiles. The considered solution describes traversable wormholes between the branes in the two brane Randall-Sundrum model and was previously found within Einstein gravity with a conformally coupled scalar field. The evolution of perturbations of a wormhole is similar to that of a black hole and represents damped oscillations (<span class="hlt">ringing</span>) at intermediately late times, which are suppressed by power-law tails (proportional to t{sup -2} for monopole perturbations) at asymptotically late times.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007epsc.conf..873G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007epsc.conf..873G"><span>Physics of planetary <span class="hlt">rings</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gorkavyi, N.</p> <p>2007-08-01</p> <p>It is difficult to enumerate all the surprises presented by the planetary <span class="hlt">rings</span>. The Saturnian <span class="hlt">rings</span> are stratified into thousands of ringlets and the Uranian <span class="hlt">rings</span> are compressed into narrow streams, which for some reason or other differ from circular orbits like the wheel of an old bicycle. The edge of the <span class="hlt">rings</span> is jagged and the <span class="hlt">rings</span> themselves are pegged down under the gravitational pressure of the satellites, bending like a ship's wake. There are spiral waves, elliptical <span class="hlt">rings</span>, strange interlacing of narrow ringlets, and to cap it all one has observed in the Neptunian <span class="hlt">ring</span> system three dense, bright arcs - like bunches of sausages on a transparent string. For celestial mechanics this is a spectacle as unnatural as a bear's tooth in the necklace of the English queen. In the dynamics of planetary <span class="hlt">rings</span> the physics of collective interaction was supplemented by taking collisions between particles into account. One was led to study a kinetic equation with a rather complex collision integral - because the collisions are inelastic - which later on made it possible, both by using the Chapman-Enskog method and by using the solution of the kinetic equation for a plasma in a magnetic field, to reduce it to a closed set of (hydrodynamical) moment equations [1]. The hydrodynamical instabilities lead to the <span class="hlt">growth</span> of short-wavelength waves and large-scale structures of the Saturnian <span class="hlt">rings</span> [1]. We have shown that the formation of the existing dense Uranian <span class="hlt">rings</span> is connected with the capture of positively drifting <span class="hlt">ring</span> particles in inner Lindblad resonances which arrest this drift [1]. After the formation of dense <span class="hlt">rings</span> at the positions of satellite resonances the collective interaction between resonant particles is amplified and the <span class="hlt">rings</span> can leave the resonance and drift away from the planet and the parent resonance. We can expect in the C <span class="hlt">ring</span> an appreciable positive ballistic particle drift caused by the erosion of the B <span class="hlt">ring</span> by micrometeorites. It is therefore natural</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21371107','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21371107"><span>Interface <span class="hlt">width</span> effect on the classical Rayleigh-Taylor instability in the weakly nonlinear regime</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wang, L. F.; Ye, W. H.; Li, Y. J.</p> <p>2010-05-15</p> <p>In this paper, the interface <span class="hlt">width</span> effects (i.e., the density gradient effects or the density transition layer effects) on the Rayleigh-Taylor instability (RTI) in the weakly nonlinear (WN) regime are investigated by numerical simulation (NS). It is found that the interface <span class="hlt">width</span> effects dramatically influence the linear <span class="hlt">growth</span> rate in the linear <span class="hlt">growth</span> regime and the mode coupling process in the WN <span class="hlt">growth</span> regime. First, the interface <span class="hlt">width</span> effects decrease the linear <span class="hlt">growth</span> rate of the RTI, particularly for the short perturbation wavelengths. Second, the interface <span class="hlt">width</span> effects suppress (reduce) the third-order feedback to the fundamental mode, which induces the nonlinear saturation amplitude (NSA) to exceed the classical prediction, 0.1lambda. The wider the density transition layer is, the larger the NSA is. The NSA in our NS can reach a half of its perturbation wavelength. Finally, the interface <span class="hlt">width</span> effects suppress the generation and the <span class="hlt">growth</span> of the second and the third harmonics. The ability to suppress the harmonics' <span class="hlt">growth</span> increases with the interface <span class="hlt">width</span> but decreases with the perturbation wavelength. On the whole, in the WN regime, the interface <span class="hlt">width</span> effects stabilize the RTI, except for an enhancement of the NSA, which is expected to improve the understanding of the formation mechanism for the astrophysical jets, and for the jetlike long spikes in the high energy density physics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19..431Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19..431Z"><span>Alpine Holocene Tree <span class="hlt">Ring</span> Isotope Records - A Synthesis of a Multi-Proxy Approach in Dendroclimatology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ziehmer, Malin Michelle; Nicolussi, Kurt; Schlüchter, Christian; Leuenberger, Markus</p> <p>2017-04-01</p> <p>High-resolution climate reconstructions based on tree-<span class="hlt">ring</span> proxies are often limited by the individual segment length of living trees selected at the defined sampling sites, which mostly results in relatively short multi-centennial proxy series. A potential extension of living wood records comprise the addition of subfossil and archeological wood remains resulting in chronologies and associated climate reconstructions which are able to cover a few millennia in central Europe (e.g. Büntgen et al., 2011). However, existing multi-millennial tree-<span class="hlt">ring</span> <span class="hlt">width</span> chronologies in central Europe rank among the longest continuous chronologies world-wide and span the entire Holocene (Becker et al., 1993; Nicolussi et al. 2009). So far, these chronologies have mainly been used for dating subfossil wood samples, floating chronologies and archeological artifacts, but only in parts for reconstructing climate. Finds of Holocene wood remains in glacier forefields, peat bogs and small lakes allow us not only to establish such long-term tree-<span class="hlt">ring</span> <span class="hlt">width</span> records; further they offer the possibility to establish multi-millennial proxy records for the entire Holocene by using a multi-proxy approach which includes both tree-<span class="hlt">ring</span> <span class="hlt">width</span> and triple stable isotope ratios. As temperature limits tree <span class="hlt">growth</span> at the Alpine upper tree line, the existing tree-<span class="hlt">ring</span> <span class="hlt">width</span> records are currently limited to reconstruct a single environmental variable. In the framework of the project Alpine Holocene Tree <span class="hlt">Ring</span> Isotope Records, we combine tree-<span class="hlt">ring</span> <span class="hlt">width</span>, cellulose content as well as carbon, oxygen and hydrogen isotope series in a multi-proxy approach which allows the reconstruction of past environments by combining both Holocene wood remains and recent tree samples from two Alpine tree-line species. For this purpose, α-cellulose is prepared from 5-year tree <span class="hlt">ring</span> blocks following the procedure after Boettger et al. (2007) and subsequently crushed by ultrasonic homogenization (Laumer et al., 2009). The</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016DPS....4812113G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016DPS....4812113G"><span>Simulation of <span class="hlt">Rings</span> about Ellipsoidal Bodies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gupta, Akash; Nadkarni-Ghosh, Sharvari; Sharma, Ishan</p> <p>2016-10-01</p> <p>Recent discovery of <span class="hlt">rings</span> around Chariklo, a centaur orbiting the Sun (F. Braga-Ribas et al., 2014) and speculations of <span class="hlt">rings</span> around minor planet, Chiron (Ortiz et al., 2015), Saturn's satellites, Rhea (Jones et al., 2008; Schenk et al., 2011), Iapetus (Ip, 2006) or exoplanets, suggest that <span class="hlt">rings</span> about non-spherical bodies is perhaps a more general phenomenon than anticipated. As a first step towards understanding such systems, we examine the dynamical behavior of <span class="hlt">rings</span> around similar bodies using N-body simulations. Our code employs the `local simulation method' (Wisdom & Tremaine, 1988; Salo, 1995) and accounts for particle interactions via collisions using Discrete Element Method (Cundall & Strack, 1978; Bhateja et al., 2016) and mutual gravitation. The central body has been modeled as an axisymmetric ellipsoid characterized by its axis ratio, or defined via characteristic frequencies (circular, vertical and epicyclic frequency) representing the gravitational field of an axisymmetric body. We vary the central body's characterizing parameter and observe the change in various <span class="hlt">ring</span> properties like the granular temperature, impact frequency, radial <span class="hlt">width</span> and vertical thickness. We also look into the effect on <span class="hlt">ring</span> properties upon variation in the size of the central body-<span class="hlt">ring</span> system. Further, we investigate the role of characteristic frequencies in dictating the <span class="hlt">ring</span> dynamics, and how this could help in qualitatively estimating the <span class="hlt">ring</span> dynamics about any arbitrary central body with symmetry about the equatorial plane and the axis normal to it.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title14-vol3/pdf/CFR-2010-title14-vol3-sec121-95.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title14-vol3/pdf/CFR-2010-title14-vol3-sec121-95.pdf"><span>14 CFR 121.95 - Route <span class="hlt">width</span>.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-01-01</p> <p>.... (a) Approved routes and route segments over U.S. Federal airways or foreign airways (and advisory... designated <span class="hlt">width</span> of those airways or routes. Whenever the Administrator finds it necessary to determine the <span class="hlt">width</span> of other approved routes, he considers the following: (1) Terrain clearance. (2) Minimum en route...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title14-vol3/pdf/CFR-2011-title14-vol3-sec121-95.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title14-vol3/pdf/CFR-2011-title14-vol3-sec121-95.pdf"><span>14 CFR 121.95 - Route <span class="hlt">width</span>.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-01-01</p> <p>.... (a) Approved routes and route segments over U.S. Federal airways or foreign airways (and advisory... designated <span class="hlt">width</span> of those airways or routes. Whenever the Administrator finds it necessary to determine the <span class="hlt">width</span> of other approved routes, he considers the following: (1) Terrain clearance. (2) Minimum en route...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title14-vol3/pdf/CFR-2013-title14-vol3-sec121-95.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title14-vol3/pdf/CFR-2013-title14-vol3-sec121-95.pdf"><span>14 CFR 121.95 - Route <span class="hlt">width</span>.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-01-01</p> <p>.... (a) Approved routes and route segments over U.S. Federal airways or foreign airways (and advisory... designated <span class="hlt">width</span> of those airways or routes. Whenever the Administrator finds it necessary to determine the <span class="hlt">width</span> of other approved routes, he considers the following: (1) Terrain clearance. (2) Minimum en route...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title14-vol3/pdf/CFR-2014-title14-vol3-sec121-95.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title14-vol3/pdf/CFR-2014-title14-vol3-sec121-95.pdf"><span>14 CFR 121.95 - Route <span class="hlt">width</span>.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2014&page.go=Go">Code of Federal Regulations, 2014 CFR</a></p> <p></p> <p>2014-01-01</p> <p>.... (a) Approved routes and route segments over U.S. Federal airways or foreign airways (and advisory... designated <span class="hlt">width</span> of those airways or routes. Whenever the Administrator finds it necessary to determine the <span class="hlt">width</span> of other approved routes, he considers the following: (1) Terrain clearance. (2) Minimum en route...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title14-vol3/pdf/CFR-2012-title14-vol3-sec121-95.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title14-vol3/pdf/CFR-2012-title14-vol3-sec121-95.pdf"><span>14 CFR 121.95 - Route <span class="hlt">width</span>.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-01-01</p> <p>.... (a) Approved routes and route segments over U.S. Federal airways or foreign airways (and advisory... designated <span class="hlt">width</span> of those airways or routes. Whenever the Administrator finds it necessary to determine the <span class="hlt">width</span> of other approved routes, he considers the following: (1) Terrain clearance. (2) Minimum en route...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26960389','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26960389"><span>Tree-<span class="hlt">ring</span> δ13C and δ18O, leaf δ13C and wood and leaf N status demonstrate tree <span class="hlt">growth</span> strategies and predict susceptibility to disturbance.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Billings, S A; Boone, A S; Stephen, F M</p> <p>2016-05-01</p> <p>Understanding how tree <span class="hlt">growth</span> strategies may influence tree susceptibility to disturbance is an important goal, especially given projected increases in diverse ecological disturbances this century. We use <span class="hlt">growth</span> responses of tree <span class="hlt">rings</span> to climate, relationships between tree-<span class="hlt">ring</span> stable isotopic signatures of carbon (δ(13)C) and oxygen (δ(18)O), wood nitrogen concentration [N], and contemporary leaf [N] and δ(13)C values to assess potential historic drivers of tree photosynthesis in dying and apparently healthy co-occurring northern red oak (Quercus rubra L. (Fagaceae)) during a region-wide oak decline event in Arkansas, USA. Bole <span class="hlt">growth</span> of both healthy and dying trees responded negatively to drought severity (Palmer Drought Severity Index) and temperature; healthy trees exhibited a positive, but small, response to growing season precipitation. Contrary to expectations, tree-<span class="hlt">ring</span> δ(13)C did not increase with drought severity. A significantly positive relationship between tree-<span class="hlt">ring</span> δ(13)C and δ(18)O was evident in dying trees (P < 0.05) but not in healthy trees. Healthy trees' wood exhibited lower [N] than that of dying trees throughout most of their lives (P < 0.05), and we observed a significant, positive relationship (P < 0.05) in healthy trees between contemporary leaf δ(13)C and leaf N (by mass), but not in dying trees. Our work provides evidence that for plants in which strong relationships between δ(13)C and δ(18)O are not evident, δ(13)C may be governed by plant N status. The data further imply that historic photosynthesis in healthy trees was linked to N status and, perhaps, C sink strength to a greater extent than in dying trees, in which tree-<span class="hlt">ring</span> stable isotopes suggest that historic photosynthesis was governed primarily by stomatal regulation. This, in turn, suggests that assessing the relative dominance of photosynthetic capacity vs stomatal regulation as drivers of trees' C accrual may be a feasible means of predicting tree</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4886288','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4886288"><span>Tree-<span class="hlt">ring</span> δ13C and δ18O, leaf δ13C and wood and leaf N status demonstrate tree <span class="hlt">growth</span> strategies and predict susceptibility to disturbance</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Billings, S.A.; Boone, A.S.; Stephen, F.M.</p> <p>2016-01-01</p> <p>Understanding how tree <span class="hlt">growth</span> strategies may influence tree susceptibility to disturbance is an important goal, especially given projected increases in diverse ecological disturbances this century. We use <span class="hlt">growth</span> responses of tree <span class="hlt">rings</span> to climate, relationships between tree-<span class="hlt">ring</span> stable isotopic signatures of carbon (δ13C) and oxygen (δ18O), wood nitrogen concentration [N], and contemporary leaf [N] and δ13C values to assess potential historic drivers of tree photosynthesis in dying and apparently healthy co-occurring northern red oak (Quercus rubra L. (Fagaceae)) during a region-wide oak decline event in Arkansas, USA. Bole <span class="hlt">growth</span> of both healthy and dying trees responded negatively to drought severity (Palmer Drought Severity Index) and temperature; healthy trees exhibited a positive, but small, response to growing season precipitation. Contrary to expectations, tree-<span class="hlt">ring</span> δ13C did not increase with drought severity. A significantly positive relationship between tree-<span class="hlt">ring</span> δ13C and δ18O was evident in dying trees (P < 0.05) but not in healthy trees. Healthy trees’ wood exhibited lower [N] than that of dying trees throughout most of their lives (P < 0.05), and we observed a significant, positive relationship (P < 0.05) in healthy trees between contemporary leaf δ13C and leaf N (by mass), but not in dying trees. Our work provides evidence that for plants in which strong relationships between δ13C and δ18O are not evident, δ13C may be governed by plant N status. The data further imply that historic photosynthesis in healthy trees was linked to N status and, perhaps, C sink strength to a greater extent than in dying trees, in which tree-<span class="hlt">ring</span> stable isotopes suggest that historic photosynthesis was governed primarily by stomatal regulation. This, in turn, suggests that assessing the relative dominance of photosynthetic capacity vs stomatal regulation as drivers of trees’ C accrual may be a feasible means of predicting tree responses to some</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EOSTr..94R.132S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EOSTr..94R.132S"><span>Tree <span class="hlt">ring</span> records capture long-term memory in climate systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schultz, Colin</p> <p>2013-03-01</p> <p>Measuring tree <span class="hlt">rings</span> is a mainstay technique for estimating ancient climatic conditions, with a tree's year-by-year <span class="hlt">growth</span> reflecting changes in precipitation and temperature. In some cases, paleoclimatological records compiled from tree <span class="hlt">ring</span> measurements can stretch for thousands of years. Based on recent research, climatologists have found that hydrological and other systems have long-term memory. Drawing on tree <span class="hlt">ring</span> measurements compiled from across the continental United States, Bowers et al. sought to determine whether such long-term relationships are preserved in <span class="hlt">ring</span> <span class="hlt">width</span> measurements. The authors analyzed the Hurst parameter—a measure of long-term memory—of 697 different tree <span class="hlt">ring</span> records that were collected from 10 tree species from locations across the United States. They found that though each tree species had a different mean value for its Hurst parameter, meaning that each species recorded long-term trends in the climate differently, they all fell within the range suggestive of their being able to properly represent long-term memory.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27508933','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27508933"><span>Climate Response of Tree Radial <span class="hlt">Growth</span> at Different Timescales in the Qinling Mountains.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sun, Changfeng; Liu, Yu</p> <p>2016-01-01</p> <p>The analysis of the tree radial <span class="hlt">growth</span> response to climate is crucial for dendroclimatological research. However, the response relationships between tree-<span class="hlt">ring</span> indices and climatic factors at different timescales are not yet clear. In this study, the tree-<span class="hlt">ring</span> <span class="hlt">width</span> of Huashan pine (Pinus armandii) from Huashan in the Qinling Mountains, north-central China, was used to explore the response differences of tree <span class="hlt">growth</span> to climatic factors at daily, pentad (5 days), dekad (10 days) and monthly timescales. Correlation function and linear regression analysis were applied in this paper. The tree-<span class="hlt">ring</span> <span class="hlt">width</span> showed a more sensitive response to daily and pentad climatic factors. With the timescale decreasing, the absolute value of the maximum correlation coefficient between the tree-<span class="hlt">ring</span> data and precipitation increases as well as temperature (mean, minimum and maximum temperature). Compared to the other three timescales, pentad was more suitable for analysing the response of tree <span class="hlt">growth</span> to climate. Relative to the monthly climate data, the association between the tree-<span class="hlt">ring</span> data and the pentad climate data was more remarkable and accurate, and the reconstruction function based on the pentad climate was also more reliable and stable. We found that the major climatic factor limiting Huashan pine <span class="hlt">growth</span> was the precipitation of pentads 20-35 (from April 6 to June 24) rather than the well-known April-June precipitation. The pentad was also proved to be a better timescale for analysing the climate and tree <span class="hlt">growth</span> in the western and eastern Qinling Mountains. The formation of the earlywood density of Chinese pine (Pinus tabulaeformis) from Shimenshan in western Qinling was mainly affected by the maximum temperature of pentads 28-32 (from May 16 to June 9). The maximum temperature of pentads 28-33 (from May 16 to June 14) was the major factor affecting the <span class="hlt">ring</span> <span class="hlt">width</span> of Chinese pine from Shirenshan in eastern Qinling.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4980003','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4980003"><span>Climate Response of Tree Radial <span class="hlt">Growth</span> at Different Timescales in the Qinling Mountains</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Sun, Changfeng; Liu, Yu</p> <p>2016-01-01</p> <p>The analysis of the tree radial <span class="hlt">growth</span> response to climate is crucial for dendroclimatological research. However, the response relationships between tree-<span class="hlt">ring</span> indices and climatic factors at different timescales are not yet clear. In this study, the tree-<span class="hlt">ring</span> <span class="hlt">width</span> of Huashan pine (Pinus armandii) from Huashan in the Qinling Mountains, north-central China, was used to explore the response differences of tree <span class="hlt">growth</span> to climatic factors at daily, pentad (5 days), dekad (10 days) and monthly timescales. Correlation function and linear regression analysis were applied in this paper. The tree-<span class="hlt">ring</span> <span class="hlt">width</span> showed a more sensitive response to daily and pentad climatic factors. With the timescale decreasing, the absolute value of the maximum correlation coefficient between the tree-<span class="hlt">ring</span> data and precipitation increases as well as temperature (mean, minimum and maximum temperature). Compared to the other three timescales, pentad was more suitable for analysing the response of tree <span class="hlt">growth</span> to climate. Relative to the monthly climate data, the association between the tree-<span class="hlt">ring</span> data and the pentad climate data was more remarkable and accurate, and the reconstruction function based on the pentad climate was also more reliable and stable. We found that the major climatic factor limiting Huashan pine <span class="hlt">growth</span> was the precipitation of pentads 20–35 (from April 6 to June 24) rather than the well-known April–June precipitation. The pentad was also proved to be a better timescale for analysing the climate and tree <span class="hlt">growth</span> in the western and eastern Qinling Mountains. The formation of the earlywood density of Chinese pine (Pinus tabulaeformis) from Shimenshan in western Qinling was mainly affected by the maximum temperature of pentads 28–32 (from May 16 to June 9). The maximum temperature of pentads 28–33 (from May 16 to June 14) was the major factor affecting the <span class="hlt">ring</span> <span class="hlt">width</span> of Chinese pine from Shirenshan in eastern Qinling. PMID:27508933</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22384574','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22384574"><span>[Responses of Pinus sylvestris var. mongolica radial <span class="hlt">growth</span> to climate warming in Great Xing' an Mountins: a case study in Mangui].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhang, Xing-Liang; He, Xing-Yuan; Chen, Zhen-Ju; Cui, Ming-Xing; Li, Na</p> <p>2011-12-01</p> <p>Based on the theory and methodology of dendrochronology, the tree <span class="hlt">ring</span> <span class="hlt">width</span> chronology of Pinus sylvestris var. mongolica in Mangui of Great Xing' an Mountains was developed, and the relationships between the standardized tree <span class="hlt">ring</span> <span class="hlt">width</span> chronology and local climate factors (temperature and precipitation) as well as the effects of climate factors on the P. sylvestris var. mongolica radial <span class="hlt">growth</span> were analyzed. In this region, the mean monthly temperature in April-August of current year was the main factor limiting the radial <span class="hlt">growth</span>, and the increasing mean monthly temperature from April to August had negative effects to the radial <span class="hlt">growth</span>. The simulation of the variations of the radial <span class="hlt">growth</span> by the mean monthly temperature change in April-August showed that the radial <span class="hlt">growth</span> of P. sylvestris var. mongolica would present a declining trend accompanied with the warmer and drier regional climate condition.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21587453','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21587453"><span>NUCLEAR <span class="hlt">RINGS</span> IN GALAXIES-A KINEMATIC PERSPECTIVE</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Mazzuca, Lisa M.; Swaters, Robert A.; Veilleux, Sylvain; Knapen, Johan H.</p> <p>2011-10-01</p> <p>We combine DensePak integral field unit and TAURUS Fabry-Perot observations of 13 nuclear <span class="hlt">rings</span> to show an interconnection between the kinematic properties of the <span class="hlt">rings</span> and their resonant origin. The nuclear <span class="hlt">rings</span> have regular and symmetric kinematics, and lack strong non-circular motions. This symmetry, coupled with a direct relationship between the position angles and ellipticities of the <span class="hlt">rings</span> and those of their host galaxies, indicates that the <span class="hlt">rings</span> are in the same plane as the disk and are circular. From the rotation curves derived, we have estimated the compactness (v{sup 2}/r) up to the turnover radius, which is where the nuclear <span class="hlt">rings</span> reside. We find that there is evidence of a correlation between compactness and <span class="hlt">ring</span> <span class="hlt">width</span> and size. Radially wide <span class="hlt">rings</span> are less compact, and thus have lower mass concentration. The compactness increases as the <span class="hlt">ring</span> <span class="hlt">width</span> decreases. We also find that the nuclear <span class="hlt">ring</span> size is dependent on the bar strength, with weaker bars allowing <span class="hlt">rings</span> of any size to form.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19860520','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19860520"><span>A case of <span class="hlt">ring</span> chromosome 18 syndrome treated with a combined orthodontic-prosthodontic approach.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ono, Takashi; Okuma, Mizue; Hamada, Takashi; Motohashi, Nobuyoshi; Moriyama, Keiji</p> <p>2010-03-01</p> <p>The aim of this study was to report the case of a Japanese subject with <span class="hlt">ring</span> chromosome 18 syndrome. A cephalometric analysis was performed, and the treatment procedure is described. Lateral and posteroanterior cephalograms were compared with Japanese norms. Dental anomalies were evaluated by a model analysis. The outcome of orthodontic-prosthodontic treatment was evaluated by comparing cephalograms during the course of treatment. The cephalometric analysis showed a reduction in the cranial base length and cranial <span class="hlt">width</span>, midfacial depth, and height and <span class="hlt">width</span>. Comparison of lateral cephalograms at age 16 years 6 months and 22 years 4 months showed late <span class="hlt">growth</span> of the mandible. The model analysis showed that all of the teeth, except for the mandibular canine, were small. Characteristic craniofacial and dental anomalies were clarified. Successful oral rehabilitation was achieved by combined orthodontic-prosthodontic treatment.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15519988','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15519988"><span>Scots pine responses to elevated temperature and carbon dioxide concentration: <span class="hlt">growth</span> and wood properties.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kilpeläinen, Antti; Peltola, Heli; Ryyppö, Aija; Kellomäki, Seppo</p> <p>2005-01-01</p> <p><span class="hlt">Growth</span> and wood properties of 20-year-old Scots pine (Pinus sylvestris L.) trees were studied for 6 years in 16 closed chambers providing a factorial combination of two temperature regimes (ambient and elevated) and two carbon dioxide concentrations ([CO2]) (ambient and twice ambient). The elevation of temperature corresponded to the predicted effect at the site of a doubling in atmospheric [CO2]. Annual height and radial <span class="hlt">growth</span> and wood properties were analyzed during 1997-2002. Physical wood properties analyzed included early- and latewood <span class="hlt">widths</span> and their proportions, intra-<span class="hlt">ring</span> wood densities, early- and latewood density and mean fiber length. Chemical wood properties analyzed included concentrations of acetone-soluble extractives, lignin, cellulose and hemicellulose. There were no significant treatment effects on height <span class="hlt">growth</span> during the 6-year study. Elevated [CO2] increased <span class="hlt">ring</span> <span class="hlt">width</span> by 66 and 47% at ambient and elevated temperatures, respectively. At ambient [CO2], elevated temperature increased <span class="hlt">ring</span> <span class="hlt">width</span> by 19%. Increased <span class="hlt">ring</span> <span class="hlt">width</span> in response to elevated [CO2] resulted from increases in both early- and latewood <span class="hlt">width</span>; however, there was no effect of the treatments on early- and latewood proportions. Mean wood density, earlywood density and fiber length increased in response to elevated temperature. The chemical composition of wood was affected by elevated [CO2], which reduced the cellulose concentration, and by elevated temperature, which reduced the concentration of acetone-soluble extractives. Thus, over the 6-year period, radial <span class="hlt">growth</span> was significantly increased by elevated [CO2], and some wood properties were significantly affected by elevated temperature or elevated [CO2], or both, indicating that climate change may affect the material properties of wood.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28813429','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28813429"><span>The impact of tree age on biomass <span class="hlt">growth</span> and carbon accumulation capacity: A retrospective analysis using tree <span class="hlt">ring</span> data of three tropical tree species grown in natural forests of Suriname.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Köhl, Michael; Neupane, Prem R; Lotfiomran, Neda</p> <p>2017-01-01</p> <p>The world's forests play a pivotal role in the mitigation of global climate change. By photosynthesis they remove CO2 from the atmosphere and store carbon in their biomass. While old trees are generally acknowledged for a long carbon residence time, there is no consensus on their contribution to carbon accumulation due to a lack of long-term individual tree data. Tree <span class="hlt">ring</span> analyses, which use anatomical differences in the annual formation of wood for dating <span class="hlt">growth</span> zones, are a retrospective approach that provides <span class="hlt">growth</span> patterns of individual trees over their entire lifetime. We developed time series of diameter <span class="hlt">growth</span> and related annual carbon accumulation for 61 trees of the species Cedrela odorata L. (Meliacea), Hymenaea courbaril L. (Fabacea) and Goupia glabra Aubl. (Goupiacea). The trees grew in unmanaged tropical wet-forests of Suriname and reached ages from 84 to 255 years. Most of the trees show positive trends of diameter <span class="hlt">growth</span> and carbon accumulation over time. For some trees we observed fluctuating <span class="hlt">growth</span>-periods of lower <span class="hlt">growth</span> alternate with periods of increased <span class="hlt">growth</span>. In the last quarter of their lifetime trees accumulate on average between 39 percent (C. odorata) and 50 percent (G. glabra) of their final carbon stock. This suggests that old-<span class="hlt">growth</span> trees in tropical forests do not only contribute to carbon stocks by long carbon resistance times, but maintain high rates of carbon accumulation at later stages of their life time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016DPS....4820306B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016DPS....4820306B"><span>Chariklo's <span class="hlt">ring</span> system 1. Structure of the <span class="hlt">ring</span> system from stellar occultations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Berard, Diane; Sicardy, Bruno; Braga-Ribas, Felipe; camargo, julio; Vieira-Martins, Roberto; Assafin, Marcelo; Sickafoose, Amanda A.; Colas, François; Dauvergne, Jean-Luc; Bath, Karl-Ludwig; Maquet, Lucie; Tancredi, Gonzalo; Richichi, Andrea; Puji, Irawati; Ivanov, Valentin; Bradshaw, Jonathan; Broughton, John; Meza, Erick; Ortiz, Jose-Luis; Duffard, Rene; Leiva, Rodrigo</p> <p>2016-10-01</p> <p>Two dense and narrow <span class="hlt">rings</span> around Chariklo (the largest centaur object known to date) were discovered by stellar occultation on June 3, 2013 (Braga-Ribas et al., Nature 508, 72, 2014). The main and larger <span class="hlt">ring</span> is called C1R, while the faintest one is called C2R.Here we report six others occultations by Chariklo's <span class="hlt">ring</span> system observed on February 16, March 16, April 29, June 28, 2014 and April 26, May 12, 2015. They provide a total of fifteen <span class="hlt">ring</span> profiles, among which are four resolved profiles of C1R.The latter exhibits a W-shape profile that is essentially opaque at the edges. Its <span class="hlt">width</span> varies from 4.8 to 7.7 km over the available longitude range. Those caracteristics have been detected in Uranus elliptic <span class="hlt">rings</span>. The equivalent <span class="hlt">width</span> We (normal opacity x physical radial <span class="hlt">width</span>) of C1R is 2 km with typical rms of 1 km, while C2R has We of 0.2 km (rms ~ 0.1 km). None of the <span class="hlt">rings</span> exhibits variation of We with longitude.Assuming the <span class="hlt">rings</span> are circular, we can exhibit a pole which is compatible with the two multi-chord <span class="hlt">ring</span> detections (June 3, 2013 and April 29, 2014): αp=151.4° and δp=41.5°. We will then estimate an upper limit of a possible <span class="hlt">ring</span> eccentricity based on those two observations.Part of the research leading to these results has received funding from the European Research Council under the European Community's H2020 (2014-2020/ ERC Grant Agreement n 669416 "LUCKY STAR").</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21289923','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21289923"><span>Critical comparison of Kramers' fission <span class="hlt">width</span> with the stationary <span class="hlt">width</span> from the Langevin equation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sadhukhan, Jhilam; Pal, Santanu</p> <p>2009-06-15</p> <p>It is shown that Kramers' fission <span class="hlt">width</span>, originally derived for a system with constant inertia, can be extended to systems with a deformation-dependent collective inertia, which is the case for nuclear fission. The predictions of Kramers' <span class="hlt">width</span> for systems with variable inertia are found to be in very good agreement with the stationary fission <span class="hlt">widths</span> obtained by solving the corresponding Langevin equations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/50602','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/50602"><span>Building the Forest Inventory and Analysis Tree-<span class="hlt">Ring</span> Data set</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Robert J. DeRose; John D. Shaw; James N. Long</p> <p>2017-01-01</p> <p>The Interior West Forest Inventory and Analysis (IW-FIA) program measures forestland conditions at great extent with relatively high spatial resolution, including the collection of tree-<span class="hlt">ring</span> data. We describe the development of an unprecedented spatial tree-<span class="hlt">ring</span> data set for the IW-FIA that enhances the baseline plot data by incorporating <span class="hlt">ring-width</span> increment measured...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011PhRvE..83f1102B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011PhRvE..83f1102B"><span>Kinetics of <span class="hlt">ring</span> formation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ben-Naim, E.; Krapivsky, P. L.</p> <p>2011-06-01</p> <p>We study reversible polymerization of <span class="hlt">rings</span>. In this stochastic process, two monomers bond and, as a consequence, two disjoint <span class="hlt">rings</span> may merge into a compound <span class="hlt">ring</span> or a single <span class="hlt">ring</span> may split into two fragment <span class="hlt">rings</span>. This aggregation-fragmentation process exhibits a percolation transition with a finite-<span class="hlt">ring</span> phase in which all <span class="hlt">rings</span> have microscopic length and a giant-<span class="hlt">ring</span> phase where macroscopic <span class="hlt">rings</span> account for a finite fraction of the entire mass. Interestingly, while the total mass of the giant <span class="hlt">rings</span> is a deterministic quantity, their total number and their sizes are stochastic quantities. The size distribution of the macroscopic <span class="hlt">rings</span> is universal, although the span of this distribution increases with time. Moreover, the average number of giant <span class="hlt">rings</span> scales logarithmically with system size. We introduce a card-shuffling algorithm for efficient simulation of the <span class="hlt">ring</span> formation process and we present numerical verification of the theoretical predictions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19870040641&hterms=pearce&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dpearce','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19870040641&hterms=pearce&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dpearce"><span>Terrace <span class="hlt">width</span> variations in complex lunar craters</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pearce, Steven J.; Melosh, H. J.</p> <p>1986-01-01</p> <p>The <span class="hlt">widths</span> of terrace structures in complex craters on the moon are compared to existing theoretical models of their origin. Terrace <span class="hlt">widths</span> in an individual crater increase monotonically outward toward the crater rim. Similarly, the <span class="hlt">width</span> W of the terraces lying closest to the rim of a crater of diameter D increases monotonically, obeying a least-squares power-law relation WS (km) = 0.09D exp 0.87 km). A simple model of slumping that ignores inertial forces and assumes a constant bedrock yield strength is in good agreement with the observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18824763','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18824763"><span>Saddle-shaped mitral valve annuloplasty <span class="hlt">rings</span> experience lower forces compared with flat <span class="hlt">rings</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jensen, Morten O; Jensen, Henrik; Smerup, Morten; Levine, Robert A; Yoganathan, Ajit P; Nygaard, Hans; Hasenkam, J Michael; Nielsen, Sten L</p> <p>2008-09-30</p> <p>New insight into the 3D dynamic behavior of the mitral valve has prompted a reevaluation of annuloplasty <span class="hlt">ring</span> designs. Force balance analysis indicates correlation between annulus forces and stresses in leaflets and chords. Improving this stress distribution can intuitively enhance the durability of mitral valve repair. We tested the hypothesis that saddle-shaped annuloplasty <span class="hlt">rings</span> have superior uniform systolic force distribution compared with a nonuniform force distribution in flat annuloplasty <span class="hlt">rings</span>. Sixteen 80-kg pigs had a flat (n=8) or saddle-shaped (n=8) mitral annuloplasty <span class="hlt">ring</span> implanted. Mitral annulus 3D dynamic geometry was obtained with sonomicrometry before <span class="hlt">ring</span> insertion. Strain gauges mounted on dedicated D-shaped rigid flat and saddle-shaped annuloplasty <span class="hlt">rings</span> provided the intraoperative force distribution perpendicular to the annular plane. Average systolic annular height to commissural <span class="hlt">width</span> ratio before <span class="hlt">ring</span> implantation was 14.0%+/-1.6%. After flat and saddle shaped <span class="hlt">ring</span> implantation, the annulus was fixed in the diastolic (9.0%+/-1.0%) and systolic (14.3%+/-1.3%) configuration, respectively (P<0.01). Force accumulation was seen from the anterior (0.72N+/-0.14N) and commissural annular segments (average 1.38N+/-0.27N) of the flat <span class="hlt">rings</span>. In these segments, the difference between the 2 types of <span class="hlt">rings</span> was statistically significant (P<0.05). The saddle-shaped annuloplasty <span class="hlt">rings</span> did not experience forces statistically significantly larger than zero in any annular segments. Saddle-shaped annuloplasty <span class="hlt">rings</span> provide superior uniform annular force distribution compared to flat <span class="hlt">rings</span> and appear to represent a configuration that minimizes out-of-plane forces that could potentially be transmitted to leaflets and chords. This may have important implications for annuloplasty <span class="hlt">ring</span> selections.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.2347S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.2347S"><span>A measuring tool for tree-<span class="hlt">rings</span> analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shumilov, Oleg; Kanatjev, Alexander; Kasatkina, Elena</p> <p>2013-04-01</p> <p>A special tool has been created for the annual tree-<span class="hlt">ring</span> <span class="hlt">widths</span> measurement and analysis. It consists of professional scanner, computer system and software. This created complex in many aspects does not yield the similar systems (LINTAB, WinDENDRO), but in comparison to manual measurement systems, it offers a number of advantages: productivity gain, possibility of archiving the results of the measurements at any stage of the processing, operator comfort. It has been developed a new software, allowing processing of samples of different types (cores, saw cuts), including those which is difficult to process, having got a complex wood structure (inhomogeneity of growing in different directions, missed, light and false <span class="hlt">rings</span> etc.). This software can analyze pictures made with optical scanners, analog or digital cameras. The complex software program was created on programming language C++, being compatible with modern operating systems like Windows X. Annual <span class="hlt">ring</span> <span class="hlt">widths</span> are measured along paths traced interactively. These paths can have any orientation and can be created so that <span class="hlt">ring</span> <span class="hlt">widths</span> are measured perpendicular to <span class="hlt">ring</span> boundaries. A graphic of <span class="hlt">ring-widths</span> in function of the year is displayed on a screen during the analysis and it can be used for visual and numerical cross-dating and comparison with other series or master-chronologies. <span class="hlt">Ring</span> <span class="hlt">widths</span> are saved to the text files in a special format, and those files are converted to the format accepted for data conservation in the International Tree-<span class="hlt">Ring</span> Data Bank. The created complex is universal in application that will allow its use for decision of the different problems in biology and ecology. With help of this complex it has been reconstructed a long-term juniper (1328-2004) and pine (1445-2005) tree-<span class="hlt">ring</span> chronologies on the base of samples collected at Kola Peninsula (northwestern Russia).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5558952','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5558952"><span>The impact of tree age on biomass <span class="hlt">growth</span> and carbon accumulation capacity: A retrospective analysis using tree <span class="hlt">ring</span> data of three tropical tree species grown in natural forests of Suriname</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Neupane, Prem R.</p> <p>2017-01-01</p> <p>The world’s forests play a pivotal role in the mitigation of global climate change. By photosynthesis they remove CO2 from the atmosphere and store carbon in their biomass. While old trees are generally acknowledged for a long carbon residence time, there is no consensus on their contribution to carbon accumulation due to a lack of long-term individual tree data. Tree <span class="hlt">ring</span> analyses, which use anatomical differences in the annual formation of wood for dating <span class="hlt">growth</span> zones, are a retrospective approach that provides <span class="hlt">growth</span> patterns of individual trees over their entire lifetime. We developed time series of diameter <span class="hlt">growth</span> and related annual carbon accumulation for 61 trees of the species Cedrela odorata L. (Meliacea), Hymenaea courbaril L. (Fabacea) and Goupia glabra Aubl. (Goupiacea). The trees grew in unmanaged tropical wet-forests of Suriname and reached ages from 84 to 255 years. Most of the trees show positive trends of diameter <span class="hlt">growth</span> and carbon accumulation over time. For some trees we observed fluctuating growth—periods of lower <span class="hlt">growth</span> alternate with periods of increased <span class="hlt">growth</span>. In the last quarter of their lifetime trees accumulate on average between 39 percent (C. odorata) and 50 percent (G. glabra) of their final carbon stock. This suggests that old-<span class="hlt">growth</span> trees in tropical forests do not only contribute to carbon stocks by long carbon resistance times, but maintain high rates of carbon accumulation at later stages of their life time. PMID:28813429</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=286997','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=286997"><span>Effects of agaricus lilaceps fairy <span class="hlt">rings</span> on soil aggregation and microbial community structure in relation to <span class="hlt">growth</span> stimulation of western wheatgrass (pascopyrum smithii) in Eastern Montana rangeland</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>Stimulation of plant productivity caused by Agaricus fairy <span class="hlt">rings</span> has been reported, but nothing is known about soil aggregation and the microbial community structure of the stimulated zone, particularly the communities that can bind to soil particles. We studied three concentric zones of Agaricus li...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4174874','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4174874"><span>Structural disorder and transformation in crystal <span class="hlt">growth</span>: direct observation of <span class="hlt">ring</span>-opening isomerization in a metal–organic solid solution</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Jiang, Ji-Jun; He, Jian-Rong; Lü, Xing-Qiang; Wang, Da-Wei; Li, Guo-Bi; Su, Cheng-Yong</p> <p>2014-01-01</p> <p>A rare example is reported in which discrete Ag2 L 2 <span class="hlt">ring</span> and (AgL)∞ chain motifs [L = N,N′-bis(3-imidazol-1-yl-propyl)-pyromellitic diimide] co-crystallize in the same crystal lattice with varying ratios and degrees of disorder. Crystal structures obtained from representative crystals reveal compatible packing arrangements of the cyclic and polymeric isomers within the crystal lattice, which enables them to co-exist within a crystalline solid solution. A feasible pathway for transformation between the isomers is suggested via facile rotation of the coordinating imidazolyl groups. This chemical system could provide a chance for direct observation of <span class="hlt">ring</span>-opening isomerization at the crystal surface. Mass spectrometry and 1H NMR titration show a dynamic equilibrium between cyclic and oligomeric species in solution, and a potential crystallization process is suggested involving alignment of precursors directed by aromatic stacking interactions between pyromellitic diimide units, followed by <span class="hlt">ring</span>-opening isomerization at the interface between the solid and the solution. Both cyclic and oligomeric species can act as precursors, with interconversion between them being facile due to a low energy barrier for rotation of the imidazole <span class="hlt">rings</span>. Thermogravimetric analysis and variable-temperature powder X-ray diffraction indicate a transition to a different crystalline phase around 120°C, which is associated with loss of solvent from the crystal lattice. PMID:25295173</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25295173','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25295173"><span>Structural disorder and transformation in crystal <span class="hlt">growth</span>: direct observation of <span class="hlt">ring</span>-opening isomerization in a metal-organic solid solution.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jiang, Ji-Jun; He, Jian-Rong; Lü, Xing-Qiang; Wang, Da-Wei; Li, Guo-Bi; Su, Cheng-Yong</p> <p>2014-09-01</p> <p>A rare example is reported in which discrete Ag2 L 2 <span class="hlt">ring</span> and (AgL)∞ chain motifs [L = N,N'-bis(3-imidazol-1-yl-propyl)-pyromellitic diimide] co-crystallize in the same crystal lattice with varying ratios and degrees of disorder. Crystal structures obtained from representative crystals reveal compatible packing arrangements of the cyclic and polymeric isomers within the crystal lattice, which enables them to co-exist within a crystalline solid solution. A feasible pathway for transformation between the isomers is suggested via facile rotation of the coordinating imidazolyl groups. This chemical system could provide a chance for direct observation of <span class="hlt">ring</span>-opening isomerization at the crystal surface. Mass spectrometry and (1)H NMR titration show a dynamic equilibrium between cyclic and oligomeric species in solution, and a potential crystallization process is suggested involving alignment of precursors directed by aromatic stacking interactions between pyromellitic diimide units, followed by <span class="hlt">ring</span>-opening isomerization at the interface between the solid and the solution. Both cyclic and oligomeric species can act as precursors, with interconversion between them being facile due to a low energy barrier for rotation of the imidazole <span class="hlt">rings</span>. Thermogravimetric analysis and variable-temperature powder X-ray diffraction indicate a transition to a different crystalline phase around 120°C, which is associated with loss of solvent from the crystal lattice.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009LNCS.5874..385K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009LNCS.5874..385K"><span>Bipartite Graphs of Large Clique-<span class="hlt">Width</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Korpelainen, Nicholas; Lozin, Vadim V.</p> <p></p> <p>Recently, several constructions of bipartite graphs of large clique-<span class="hlt">width</span> have been discovered in the literature. In the present paper, we propose a general framework for developing such constructions and use it to obtain new results on this topic.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17676092','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17676092"><span><span class="hlt">Ringing</span> phenomenon of the fiber <span class="hlt">ring</span> resonator.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ying, Diqing; Ma, Huilian; Jin, Zhonghe</p> <p>2007-08-01</p> <p>A resonator fiber-optic gyro (R-FOG) is a high-accuracy inertial rotation sensor based on the Sagnac effect. A fiber <span class="hlt">ring</span> resonator is the core sensing element in the R-FOG. When the frequency of the fiber <span class="hlt">ring</span> resonator input laser is swept linearly with time, <span class="hlt">ringing</span> of the output resonance curve is observed. The output field of the fiber <span class="hlt">ring</span> resonator is derived from the superposition of the light transmitted through the directional coupler directly and the multiple light components circulated in the fiber <span class="hlt">ring</span> resonator when the frequency of the laser is swept. The amplitude and phase of the output field are analyzed, and it is found that the difference in time for different light components in the fiber <span class="hlt">ring</span> resonator to reach a point of destructive interference causes the <span class="hlt">ringing</span> phenomenon. Finally the <span class="hlt">ringing</span> phenomenon is observed in experiments, and the experimental results agree with the theoretical analysis well.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA08262.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA08262.html"><span>The <span class="hlt">Ring</span> Sculptor</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2006-09-08</p> <p>Prometheus zooms across the Cassini spacecraft field of view, attended by faint streamers and deep gores in the F <span class="hlt">ring</span>. This movie sequence of five images shows the F <span class="hlt">ring</span> shepherd moon shaping the <span class="hlt">ring</span> inner edge</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA12516.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA12516.html"><span>Beyond Bright <span class="hlt">Rings</span></span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2009-12-30</p> <p>The tiny moon Pandora appears beyond the bright disk of Saturn <span class="hlt">rings</span> in this image taken by NASA Cassini spacecraft. Pandora orbits outside the F <span class="hlt">ring</span> and, in this image, is farther from Cassini than the <span class="hlt">rings</span> are.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1014874','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1014874"><span>Asymmetric dipolar <span class="hlt">ring</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Prosandeev, Sergey A.; Ponomareva, Inna V.; Kornev, Igor A.; Bellaiche, Laurent M.</p> <p>2010-11-16</p> <p>A device having a dipolar <span class="hlt">ring</span> surrounding an interior region that is disposed asymmetrically on the <span class="hlt">ring</span>. The dipolar <span class="hlt">ring</span> generates a toroidal moment switchable between at least two stable states by a homogeneous field applied to the dipolar <span class="hlt">ring</span> in the plane of the <span class="hlt">ring</span>. The <span class="hlt">ring</span> may be made of ferroelectric or magnetic material. In the former case, the homogeneous field is an electric field and in the latter case, the homogeneous field is a magnetic field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.P54B..04M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.P54B..04M"><span>Accretion in Saturn's F <span class="hlt">Ring</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Meinke, B. K.; Esposito, L. W.; Stewart, G.</p> <p>2012-12-01</p> <p> opaque in occultation. We suggest that Icicles may evolve into Moonlets, which are an order of magnitude less abundant in UVIS observations. Motivated by the observations and previous models, I develop a more rigorous model of the evolution of aggregates in Saturn's F <span class="hlt">ring</span> via tidally-modified accretion. I apply the model to the F <span class="hlt">ring</span> for bodies of constant density undergoing binary collisions. Because the locations of the UVIS-observed clump-associated features are weakly correlated to the location of Prometheus (Esposito et al. 2012) and images show material stirred up after Prometheus passage (Murray et al. 2008), we develop an additional production term describing "enhanced <span class="hlt">growth</span>" beyond sticking of hard spheres in binary collisions. In the scenario we devise, Prometheus creates high-density regions in which larger bodies efficiently sweep up smaller bodies. Including a term for this <span class="hlt">growth</span> mechanism in the numerical model results in the modeled size distribution evolving to a state consistent with observations. Together, the observations and model tell a story of how moonlets are made. Prometheus may be the agent responsible for moonlet <span class="hlt">growth</span>, a complicated and rare process in the F <span class="hlt">ring</span>. This can explain how accretion gets the upper hand in forming F <span class="hlt">ring</span> aggregates. <span class="hlt">Growth</span> and destruction may be cyclical on a longer time scale. This research was supported by the Cassini project.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMGC51D0781B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMGC51D0781B"><span>Building Topographically Modified Tree-<span class="hlt">Ring</span> Chronologies from High Elevation Bristlecone Pine in the White Mountains of California, USA</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bunn, A. G.; Hughes, M. K.; Salzer, M. W.</p> <p>2010-12-01</p> <p>We analyze <span class="hlt">growth</span> rates of dozens of high elevation (~3400 m.a.s.l.) bristlecone pine trees (Pinus longaeva D.K. Bailey) from the White Mountains of California, USA by exploiting the biophysical position of the individual trees. Recent work has shown that 20th century <span class="hlt">growth</span> in the highest elevation bristlecone pine is greater than at any point in recent millennia. This phenomenon is coincident with increased temperatures over the instrumental climate record. While both temperature and moisture availability appear to influence <span class="hlt">growth</span>, the trade-off of these limiting factors is not well understood. The White Mountains are dominated by steep, rugged terrain. We suggest that even in relatively small areas, the complexity of terrain in high mountain systems can alter the limiting <span class="hlt">growth</span> factors of individual trees and that these differences may be of value to better understand bristlecone pine <span class="hlt">growth</span>. In a multivariate analysis we are able to isolate different patterns of <span class="hlt">growth</span> based that are associated with topographic indices reflecting variations in local temperature lapse rates and soil moisture anomalies. When we build topographically modified mean <span class="hlt">ring-width</span> chronologies along these gradients we find substantial variation between the chronologies in the time and frequency domains. We also find that the correlations with the instrumental climate record vary and that we are partially able to unmix temperature versus precipitation signals. These differences appear consistent with mechanistic understanding of the control of tree-<span class="hlt">ring</span> variability using a process-based model. If these results are robust, the calculation of climate reconstructions using <span class="hlt">ring-width</span> data from these trees could be placed on a firmer, clearer, basis.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28585765','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28585765"><span>Tree-<span class="hlt">ring</span> analysis and modeling approaches yield contrary response of circumboreal forest productivity to climate change.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tei, Shunsuke; Sugimoto, Atsuko; Yonenobu, Hitoshi; Matsuura, Yojiro; Osawa, Akira; Sato, Hisashi; Fujinuma, Junichi; Maximov, Trofim</p> <p>2017-06-06</p> <p>Circumboreal forest ecosystems are exposed to a larger magnitude of warming in comparison with the global average, as a result of warming-induced environmental changes. However, it is not clear how tree <span class="hlt">growth</span> in these ecosystems responds to these changes. In this study, we investigated the sensitivity of forest productivity to climate change using <span class="hlt">ring</span> <span class="hlt">width</span> indices (RWI) from a tree-<span class="hlt">ring</span> <span class="hlt">width</span> dataset accessed from the International Tree-<span class="hlt">Ring</span> Data Bank and gridded climate datasets from the Climate Research Unit. A negative relationship of RWI with summer temperature and recent reductions in RWI were typically observed in continental dry regions, such as inner Alaska and Canada, southern Europe, and the southern part of eastern Siberia. We then developed a multiple regression model with regional meteorological parameters to predict RWI, and then applied to these models to predict how tree <span class="hlt">growth</span> will respond to twenty-first-century climate change (RCP8.5 scenario). The projections showed a spatial variation and future continuous reduction in tree <span class="hlt">growth</span> in those continental dry regions. The spatial variation, however, could not be reproduced by a dynamic global vegetation model (DGVM). The DGVM projected a generally positive trend in future tree <span class="hlt">growth</span> all over the circumboreal region. These results indicate that DGVMs may overestimate future wood net primary productivity (NPP) in continental dry regions such as these; this seems to be common feature of current DGVMs. DGVMs should be able to express the negative effect of warming on tree <span class="hlt">growth</span>, so that they simulate the observed recent reduction in tree <span class="hlt">growth</span> in continental dry regions. © 2017 John Wiley & Sons Ltd.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20010048660&hterms=Lissauer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DLissauer','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20010048660&hterms=Lissauer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DLissauer"><span>Saturn's Spectacular <span class="hlt">Ring</span> System</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lissauer, Jack J.; DeVincenzi, Donald (Technical Monitor)</p> <p>2001-01-01</p> <p>Saturn's beautiful <span class="hlt">rings</span> have fascinated astronomers since they were first observed by Galileo in 1610. The main <span class="hlt">rings</span> consist of solid particles mostly in the 1 cm - 10 m range, composed primarily of water ice. The <span class="hlt">ring</span> disk is exceptionally thin - the typical local thickness of the bright <span class="hlt">rings</span> is tens of meters, whereas the diameter of the main <span class="hlt">rings</span> is 250,000 km! The main <span class="hlt">rings</span> exhibit substantial radial variations "ringlets", many of which are actively maintained via gravitational perturbations from Saturn's moons. Exterior to the main <span class="hlt">rings</span> lie tenuous dust <span class="hlt">rings</span>, which have little mass but occupy a very large volume of space. This seminar will emphasize the physics of <span class="hlt">ring</span>-moon interactions, recent advances in our understanding of various aspects of the <span class="hlt">rings</span> obtained from observations taken during 1995 when the <span class="hlt">rings</span> appeared edge-on to the Earth and then to the Sun, and observations in subsequent years from HST.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004JFM...511..311D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004JFM...511..311D"><span>Fluid entrainment by isolated vortex <span class="hlt">rings</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dabiri, John O.; Gharib, Morteza</p> <p>2004-07-01</p> <p>Of particular importance to the development of models for isolated vortex <span class="hlt">ring</span> dynamics in a real fluid is knowledge of ambient fluid entrainment by the <span class="hlt">ring</span>. This time-dependent process dictates changes in the volume of fluid that must share impulse delivered by the vortex <span class="hlt">ring</span> generator. Therefore fluid entrainment is also of immediate significance to the unsteady forces that arise due to the presence of vortex <span class="hlt">rings</span> in starting flows. Applications ranging from industrial and transportation, to animal locomotion and cardiac flows, are currently being investigated to understand the dynamical role of the observed vortex <span class="hlt">ring</span> structures. Despite this growing interest, fully empirical measurements of fluid entrainment by isolated vortex <span class="hlt">rings</span> have remained elusive. The primary difficulties arise in defining the unsteady boundary of the <span class="hlt">ring</span>, as well as an inability to maintain the vortex <span class="hlt">ring</span> in the test section sufficiently long to facilitate measurements. We present a new technique for entrainment measurement that utilizes a coaxial counter-flow to retard translation of vortex <span class="hlt">rings</span> generated from a piston cylinder apparatus, so that their <span class="hlt">growth</span> due to fluid entrainment can be observed. Instantaneous streamlines of the flow are used to determine the unsteady vortex <span class="hlt">ring</span> boundary and compute ambient fluid entrainment. Measurements indicate that the entrainment process does not promote self-similar vortex <span class="hlt">ring</span> <span class="hlt">growth</span>, but instead consists of a rapid convection-based entrainment phase during <span class="hlt">ring</span> formation, followed by a slower diffusive mechanism that entrains ambient fluid into the isolated vortex <span class="hlt">ring</span>. Entrained fluid typically constitutes 30% to 40% of the total volume of fluid carried with the vortex <span class="hlt">ring</span>. Various counter-flow protocols were used to substantially manipulate the diffusive entrainment process, producing <span class="hlt">rings</span> with entrained fluid fractions up to 65%. Measurements of vortex <span class="hlt">ring</span> <span class="hlt">growth</span> rate and vorticity distribution during diffusive entrainment</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26327638','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26327638"><span>Pollution control enhanced spruce <span class="hlt">growth</span> in the "Black Triangle" near the Czech-Polish border.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kolář, Tomáš; Čermák, Petr; Oulehle, Filip; Trnka, Miroslav; Štěpánek, Petr; Cudlín, Pavel; Hruška, Jakub; Büntgen, Ulf; Rybníček, Michal</p> <p>2015-12-15</p> <p>Norway spruce (Picea abies (L.) Karst.) stands in certain areas of Central Europe have experienced substantial dieback since the 1970s. Understanding the reasons for this decline and reexamining the response of forests to acid deposition reduction remains challenging because of a lack of long and well-replicated tree-<span class="hlt">ring</span> <span class="hlt">width</span> chronologies. Here, spruce from a subalpine area heavily affected by acid deposition (from both sulfur and nitrogen compounds) is evaluated. Tree-<span class="hlt">ring</span> <span class="hlt">width</span> measurements from 98 trees between 1000 and 1350m above sea level (a.s.l.) reflected significant May-July temperature signals. Since the 1970s, acid deposition has reduced the <span class="hlt">growth</span>-climate relationship. Efficient pollution control together with a warmer but not drier climate most likely caused the increased <span class="hlt">growth</span> of spruce stands in this region, the so-called "Black Triangle," in the 1990s.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28244107','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28244107"><span>Relative <span class="hlt">Width</span> and Height of Handwritten Letter.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lizega Rika, Joseba</p> <p>2017-02-28</p> <p>This is an exploratory study that analyzes the <span class="hlt">width</span> and the height of letters in two texts written by each of the 21 writers analyzed. After detrending the linear, text, and allograph trends, we proceeded to comparing the sizes obtained in different texts. The different detrended series were compared by means of correlation and t-test. According to the results regarding the <span class="hlt">width</span> of letters, the texts of 19 of 21 writers correlated strongly, whereas the texts of two writers did not correlate with the limits of the threshold. With regard to the height of letters, texts written by between 18 and 21 writers of 21 writers correlated strongly, whereas texts that did not correlate were within the threshold value. Regarding both the <span class="hlt">width</span> and the height of letters, of 21 writers, texts written by between 19 and 21 individuals were found to correlate strongly.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ASPC..506...17R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ASPC..506...17R"><span>The Variable Line <span class="hlt">Width</span> of Achernar</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rivinius, Th.; Townsend, R. H. D.; Baade, D.; Carciofi, A. C.; Leister, N.; Štefl, S.</p> <p>2016-11-01</p> <p>Spectroscopic observations of Achernar over the past decades, have shown the photospheric line <span class="hlt">width</span>, as measured by the rotational parameter v sin i, to vary in correlation with the emission activity. Here we present new observations, covering the most recent activity phase, and further archival data collected from the archives. The v sin i variation is confirmed. On the basis of the available data it cannot be decided with certainty whether the increased line <span class="hlt">width</span> precedes the emission activity, i.e. is a signature of the ejection mechanism, or postdates it, which would make it a signature of re-accretion of some of the disk-material. However, the observed evidence leans towards the re-accretion hypothesis. Two further stars showing the effect of variable line <span class="hlt">width</span> in correlation with emission activity, namely 66 Oph and π Aqr, are presented as well.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4904179','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4904179"><span>A field-to-desktop toolchain for X-ray CT densitometry enables tree <span class="hlt">ring</span> analysis</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>De Mil, Tom; Vannoppen, Astrid; Beeckman, Hans; Van Acker, Joris; Van den Bulcke, Jan</p> <p>2016-01-01</p> <p>Background and Aims Disentangling tree <span class="hlt">growth</span> requires more than <span class="hlt">ring</span> <span class="hlt">width</span> data only. Densitometry is considered a valuable proxy, yet laborious wood sample preparation and lack of dedicated software limit the widespread use of density profiling for tree <span class="hlt">ring</span> analysis. An X-ray computed tomography-based toolchain of tree increment cores is presented, which results in profile data sets suitable for visual exploration as well as density-based pattern matching. Methods Two temperate (Quercus petraea, Fagus sylvatica) and one tropical species (Terminalia superba) were used for density profiling using an X-ray computed tomography facility with custom-made sample holders and dedicated processing software. Key Results Density-based pattern matching is developed and able to detect anomalies in <span class="hlt">ring</span> series that can be corrected via interactive software. Conclusions A digital workflow allows generation of structure-corrected profiles of large sets of cores in a short time span that provide sufficient intra-annual density information for tree <span class="hlt">ring</span> analysis. Furthermore, visual exploration of such data sets is of high value. The dated profiles can be used for high-resolution chronologies and also offer opportunities for fast screening of lesser studied tropical tree species. PMID:27107414</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27107414','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27107414"><span>A field-to-desktop toolchain for X-ray CT densitometry enables tree <span class="hlt">ring</span> analysis.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>De Mil, Tom; Vannoppen, Astrid; Beeckman, Hans; Van Acker, Joris; Van den Bulcke, Jan</p> <p>2016-06-01</p> <p>Disentangling tree <span class="hlt">growth</span> requires more than <span class="hlt">ring</span> <span class="hlt">width</span> data only. Densitometry is considered a valuable proxy, yet laborious wood sample preparation and lack of dedicated software limit the widespread use of density profiling for tree <span class="hlt">ring</span> analysis. An X-ray computed tomography-based toolchain of tree increment cores is presented, which results in profile data sets suitable for visual exploration as well as density-based pattern matching. Two temperate (Quercus petraea, Fagus sylvatica) and one tropical species (Terminalia superba) were used for density profiling using an X-ray computed tomography facility with custom-made sample holders and dedicated processing software. Density-based pattern matching is developed and able to detect anomalies in <span class="hlt">ring</span> series that can be corrected via interactive software. A digital workflow allows generation of structure-corrected profiles of large sets of cores in a short time span that provide sufficient intra-annual density information for tree <span class="hlt">ring</span> analysis. Furthermore, visual exploration of such data sets is of high value. The dated profiles can be used for high-resolution chronologies and also offer opportunities for fast screening of lesser studied tropical tree species. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17..304K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17..304K"><span>Tree <span class="hlt">rings</span>, solar radiation and ice cover of the Barents sea</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kasatkina, Elena; Shumilov, Oleg; Timonen, Mauri; Kanatjev, Alexandr</p> <p>2015-04-01</p> <p>Intercomparisons of the Kola Peninsula tree-<span class="hlt">ring</span> records, ice cover of the Barents sea and sea and surface temperatures have been made. Tree-<span class="hlt">ring</span> series over the last 100 years showed a highly significant correlation with the sea surface temperatures and ice cover (r=-0.57, p<0.05). It should be noted that the correlation between the tree-<span class="hlt">ring</span> <span class="hlt">widths</span> and local temperatures was not so high. We suppose that a possible reason seems to be the prevailing influence of solar irradiance and their UV components on tree <span class="hlt">growth</span> in the Kola North. It is known that solar variability and fluctuations of solar irradiance in the UV band of the spectrum has increased over the last decades. In addition, there are frequent cases of total ozone content depletions (or so-called ozone mini-holes) resulting in increased UV-B. The recent studies demonstrate that many boreal and subarctic plants have increased susceptibility to UV-B radiation. An indirect confirmation of the hypothesis proposed is a close relationship between solar total irradiance and global sea surface temperature (Reid, 2000). The results of spectral MTM-analysis also revealed periodicities close to the solar cycles in the ice cover and tree-<span class="hlt">ring</span> records. These results confirm the above-mentioned interpretation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA00035.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA00035.html"><span>Uranus Tenth <span class="hlt">Ring</span></span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>1996-01-29</p> <p>On Jan. 23, 1986, NASA Voyager 2 discovered a tenth <span class="hlt">ring</span> orbiting Uranus. The tenth <span class="hlt">ring</span> is about midway between the bright, outermost epsilon <span class="hlt">ring</span> and the next <span class="hlt">ring</span> down, called delta. http://photojournal.jpl.nasa.gov/catalog/PIA00035</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/864815','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/864815"><span>Stirling engine piston <span class="hlt">ring</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Howarth, Roy B.</p> <p>1983-01-01</p> <p>A piston <span class="hlt">ring</span> design for a Stirling engine wherein the contact pressure between the piston and the cylinder is maintained at a uniform level, independent of engine conditions through a balancing of the pressure exerted upon the <span class="hlt">ring</span>'s surface and thereby allowing the contact pressure on the <span class="hlt">ring</span> to be predetermined through the use of a preloaded expander <span class="hlt">ring</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://kidshealth.org/en/teens/contraception-ring.html','NIH-MEDLINEPLUS'); return false;" href="https://kidshealth.org/en/teens/contraception-ring.html"><span>Birth Control <span class="hlt">Ring</span></span></a></p> <p><a target="_blank" href="http://medlineplus.gov/">MedlinePlus</a></p> <p></p> <p></p> <p>... Loss Surgery? A Week of Healthy Breakfasts Shyness Birth Control <span class="hlt">Ring</span> KidsHealth > For Teens > Birth Control <span class="hlt">Ring</span> Print A A A What's in this ... español Anillo vaginal anticonceptivo What Is It? The birth control <span class="hlt">ring</span> is a soft, flexible, doughnut-shaped <span class="hlt">ring</span> ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000ApJS..126..461Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000ApJS..126..461Z"><span>Equivalent <span class="hlt">Widths</span> in the Spectrum of Sirius</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhao, G.; Qiu, H. M.; Chen, Y. Q.; Li, Z. W.</p> <p>2000-02-01</p> <p>The equivalent <span class="hlt">widths</span> of total 546 lines (26 elements are included) in the spectrum of the bright Am star Sirius from 380 to 930 nm are tabulated. The high-resolution, high signal-to-noise ratio spectrum was obtained with the Coudé Echelle Spectrograph attached to the 2.16 m telescope at Beijing Astronomical Observatory (Xinglong, China). Here we also give the results of the equivalent <span class="hlt">widths</span> comparison between our measurements and those of Strom et al. and Sadakane & Ueta.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/957162','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/957162"><span>New Dust Belts of Uranus: One <span class="hlt">Ring</span>, Two <span class="hlt">Ring</span>, Red <span class="hlt">Ring</span>, Blue <span class="hlt">Ring</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>de Pater, I; Hammel, H B; Gibbard, S G; Showalter, M R</p> <p>2006-02-02</p> <p>We compare near-infrared observations of the recently discovered outer <span class="hlt">rings</span> of Uranus with HST results. We find that the inner <span class="hlt">ring</span>, R/2003 U 2, is red, whereas the outer <span class="hlt">ring</span>, R/2003 U 1, is very blue. Blue is an unusual color for <span class="hlt">rings</span>; Saturn's enigmatic E <span class="hlt">ring</span> is the only other known example. By analogy to the E <span class="hlt">ring</span>, R/2003 U 1 is probably produced via impacts into the embedded moon Mab, which apparently orbits at a location where non-gravitational perturbations favor the survival and spreading of sub-micron sized dust. R/2003 U 2 more closely resembles Saturn's G <span class="hlt">ring</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.1478P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.1478P"><span>Climate variability of Late Pleistocene deglaciation in the North American midcontinent derived from tree <span class="hlt">rings</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Panyushkina, Irina P.; Livina, Valerie N.; Leavitt, Steve W.; Mode, William N.</p> <p>2016-04-01</p> <p>High-resolution climatic proxies, such as tree <span class="hlt">rings</span> spanning millennia, have excellent potential to describe high- and low-frequency variability of climate. In practice, however, although the number of Holocene millennium-length tree-<span class="hlt">ring</span> records is still rather limited, they are especially rare for the Late Pleistocene warming period following the Last Glacial Maximum. Furthermore, detection of climatic variability in tree-<span class="hlt">ring</span> data is hindered due to intricate methodology of chronology development that transforms changes in tree geometry and a variety of environmental responses of tree <span class="hlt">growth</span> to a climatic signal. Following meticulous derivation of a new tree-<span class="hlt">ring</span> chronology, we propose a novel approach to analyze annual, decadal, multi-decadal and centennial climate-related variability of floating tree <span class="hlt">rings</span> dated back near the end of the Pleistocene. We have developed a 1400-year tree-<span class="hlt">ring</span> <span class="hlt">width</span> chronology of spruce from the Green Bay area (Wisconsin) dated from 14.5 ka to 13.1ka cal BP. This new North American midcontinent record is composed of 10 overlapped site chronologies and has two short gaps filled with linear interpolation. The Green Bay chronology covers most of the warm and moist Bølling-Allerød interstadial (14.7 ka -12.7 ka BP). Within the Bølling-Allerød interstadial, there were several abrupt and brief cooling excursions such as the Older Dryas with full-glacial-like temperature conditions. We have applied tipping point analysis to detect the changes of climate-system states during these turbulent times and obtained early warning signals in the tree-<span class="hlt">ring</span> variance. The analysis detected four short-term bifurcations dated ca. 14,450 cal BP, 14,000 cal BP, 13,750-13,600 cal BP and 13,180-13,100 cal BP. The bifurcation events of the tree-<span class="hlt">ring</span> record correspond well to the abrupt and short cooling temperature excursions of the Bølling-Allerød interstadial documented in δ18O and Ca of GRIP ice-core records, and the Laurentide ice sheet dynamics</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24483064','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24483064"><span>[Effects of elevated ozone on Pinus armandii <span class="hlt">growth</span>: a simulation study with open-top chamber].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liu, Chang-Fu; Liu, Chen; He, Xing-Yuan; Ruan, Ya-Nan; Xu, Sheng; Chen, Zhen-Ju; Peng, Jun-Jie; Li, Teng</p> <p>2013-10-01</p> <p>By using open-top chamber (OTC) and the techniques of dendrochronology, this paper studied the <span class="hlt">growth</span> of Pinus armandii under elevated ozone, and explored the evolution dynamics and adaptation mechanisms of typical forest ecosystems to ozone enrichment. Elevated ozone inhibited the stem <span class="hlt">growth</span> of P. armandii significantly, with the annual <span class="hlt">growth</span> of the stem length and diameter reduced by 35.0% and 12.9%, respectively. The annual <span class="hlt">growth</span> of tree-<span class="hlt">ring</span> <span class="hlt">width</span> and the annual <span class="hlt">ring</span> cells number decreased by 11.5% and 54.1%, respectively, but no significant change was observed in the diameter of tracheid. At regional scale, the fluctuation of ozone concentration showed significant correlation with the variation of local vegetation <span class="hlt">growth</span> (NDVI).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4880555','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4880555"><span>Biological Basis of Tree-<span class="hlt">Ring</span> Formation: A Crash Course</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Rathgeber, Cyrille B. K.; Cuny, Henri E.; Fonti, Patrick</p> <p>2016-01-01</p> <p>Wood is of crucial importance for man and biosphere. In this mini review, we present the fundamental processes involved in tree-<span class="hlt">ring</span> formation and intra-annual dynamics of cambial activity, along with the influences of the environmental factors. During wood formation, new xylem cells produced by the cambium are undergoing profound transformations, passing through successive differentiation stages, which enable them to perform their functions in trees. Xylem cell formation can be divided in five major phases: (1) the division of a cambial mother cell that creates a new cell; (2) the enlargement of this newly formed cell; (3) the deposition of its secondary wall; (4) the lignification of its cell wall; and finally, (5) its programmed cell death. In most regions of the world cambial activity follows a seasonal cycle. At the beginning of the growing season, when temperature increases, the cambium resumes activity, producing new xylem cells. These cells are disposed along radial files, and start their differentiation program according to their birth date, creating typical developmental strips in the forming xylem. The <span class="hlt">width</span> of these strips smoothly changes along the growing season. Finally, when climatic conditions deteriorate (temperature or water availability in particular), cambial activity stops, soon followed by cell enlargement, and later on by secondary wall deposition. Without a clear understanding of the xylem formation process, it is not possible to comprehend how annual <span class="hlt">growth</span> <span class="hlt">rings</span> and typical wood structures are formed, recording normal seasonal variations of the environment as well as extreme climatic events. PMID:27303426</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22720611','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22720611"><span>[Effects of urban river <span class="hlt">width</span> on the temperature and humidity of nearby green belts in summer].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ji, Peng; Zhu, Chun-Yang; Li, Shu-Hua</p> <p>2012-03-01</p> <p>As an important part of urban ecosystem, urban river plays a vital role in improving urban ecological environment. By the methods of small scale quantitative measurement, this paper analyzed the effects of seven urban rivers with different <span class="hlt">widths</span> along the Third to Fifth <span class="hlt">Ring</span> in Beijing on the air temperature and relative humidity of nearby green belts. The results showed that urban river <span class="hlt">width</span> was the main factor affecting the temperature and humidity of nearby green belts. When the river had a <span class="hlt">width</span> of 8 m, it had no effects in decreasing temperature but definite effects in increasing humidity; when the river <span class="hlt">width</span> was 14-33 m, obvious effects were observed in decreasing temperature and increasing humidity; when the river had a <span class="hlt">width</span> larger than 40 m, the effects in decreasing temperature and increasing humidity were significant and tended to be stable. There existed significant differences in the temperature and humidity between the green belts near the seven rivers and the corresponding controls. The critical <span class="hlt">width</span> of urban river for the obvious effects in decreasing temperature and increasing humidity was 44 m. The regression equation of the temperature (x) and humidity (y) for the seven green belts nearby the urban rivers in summer was y = 173.191-3.247x, with the relative humidity increased by 1.0% when the air temperature decreased by about 0.3 degrees C.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21916795','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21916795"><span>Effects of stance <span class="hlt">width</span> on performance and postural stability in national-standard pistol shooters.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hawkins, Richard N; Sefton, Joellen M</p> <p>2011-10-01</p> <p>The aim of the present study was to determine whether changing stance <span class="hlt">width</span> would result in a corresponding change in postural and/or pistol stability. Twelve national-standard male air pistol shooters performed 10 shots each at five stance <span class="hlt">widths</span> (30 cm, 45 cm, 60 cm, 75 cm, and 90 cm). Postural stability was determined by measuring centre-of-pressure changes with a dual force-platform system. Shooting mechanics measures were determined by a NOPTEL ST-2000 optoelectronic training system. Medial-lateral centre-of-pressure excursion (F₄,₄₄ = 7.17, P < 0.001, effect size = 0.99) and speed (F₄,₄₄ = 77.03, P < 0.001, effect size = 3.88) were reduced as stance <span class="hlt">width</span> decreased. Centre of gravity fine (the percentage of time held within an area the size of the ten-<span class="hlt">ring</span>) improved during narrower stance <span class="hlt">widths</span> (F₄,₃₂ = 12.49, P < 0.001, effect size = 0.71). Our findings suggest that stance <span class="hlt">width</span> affects postural and pistol stability in national-standard air pistol athletes. Moreover, the current method of suggesting a wider stance to improve shooting performance should be reconsidered and perhaps air-pistol shooters should use a 30-cm stance <span class="hlt">width</span> to improve postural stability and shooting performance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/27774','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/27774"><span><span class="hlt">Growth</span></span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>John R. Jones; George A. Schier</p> <p>1985-01-01</p> <p>This chapter considers aspen <span class="hlt">growth</span> as a process, and discusses some characteristics of the <span class="hlt">growth</span> and development of trees and stands. For the most part, factors affecting <span class="hlt">growth</span> are discussed elsewhere, particularly in the GENETICS AND VARIATION chapter and in chapters in PART 11. ECOLOGY. Aspen <span class="hlt">growth</span> as it relates to wood production is examined in the WOOD RESOURCE...</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18293910','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18293910"><span>Efficient inhibition of iron superoxide dismutase and of Trypanosoma cruzi <span class="hlt">growth</span> by benzo[g]phthalazine derivatives functionalized with one or two imidazole <span class="hlt">rings</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sanz, Ana M; Gómez-Contreras, Fernando; Navarro, Pilar; Sánchez-Moreno, Manuel; Boutaleb-Charki, Samira; Campuzano, Jose; Pardo, Mercedes; Osuna, Antonio; Cano, Carmen; Yunta, María J R; Campayo, Lucrecia</p> <p>2008-03-27</p> <p>The synthesis and trypanosomatic behavior of a new series of 1,4-bis(alkylamino)benzo[g]phthalazines 1- 4 containing the biologically significant imidazole <span class="hlt">ring</span> are reported. In vitro antiparasitic activity against Trypanosoma cruzi epimastigotes is remarkable, especially for compound 2, whereas toxicity against Vero cells is very low. Conversion of epimastigotes to metacyclic forms in the presence of the tested compounds causes significant decreases in the amastigote and trypomastigote numbers. Fe-SOD inhibition is noteworthy, whereas effect on human Cu/Zn-SOD is negligible.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17..686S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17..686S"><span>Salix polaris <span class="hlt">growth</span> responses to active layer detachment and solifluction processes in High Arctic.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Siekacz, Liliana</p> <p>2015-04-01</p> <p>The work is dedicated to demonstrate the potential of Salix polaris grow properties in the dendrogemorphologic image, analyzing periglacially induced slope processes in the high Arctic.. Observed anatomical and morphological plants responses to solifluction and active layer detachment processes are presented qualitatively and quantitatively as a summary of presented features frequency. The results are discussed against the background of the other research results in this field. The investigations was performed in Ebba valley, in the vicinity of Petunia Bay, northernmost part of Billefjorden in central Spitsbergen (Svalbard). Environmental conditions are characterized by annual precipitation sum lower than 200 mm (Hagen et al.,1993) and average summer temperature of about 5°C, with maximum daily temperatures rarely exceeding 10°C (Rachlewicz, 2009). Collected shrub material was prepared according to the methods presented by Schweingruber and Poschlod (2005). Thin (approx. 15-20μm) sections of the whole cross-section were prepared with a sledge microtome, stained with Safranine and Astra blue and finally permanently fixed on microslides with Canada balsam and dried. Snapshots were taken partially for each cross-section with digital camera (ColorView III, Olympus) connected to a microscope (Olympus BX41) and merged into one, high resolution image. After all, <span class="hlt">ring</span> <span class="hlt">widths</span> were measured in 3-4 radii in every single cross-section using ImageJ software. Analyzed plants revealed extremely harsh environmental conditions of their <span class="hlt">growth</span>. Buchwał et al. (2013) provided quantitative data concerning missing <span class="hlt">rings</span> and partially missing <span class="hlt">rings</span> in shrubs growing on Ebba valley floor. Mean <span class="hlt">ring</span> <span class="hlt">width</span> at the level of 79μm represents one of the smallest values of yearly <span class="hlt">growth</span> ever noted. The share of missing <span class="hlt">rings</span> and partially missing <span class="hlt">rings</span> was 11,2% and 13,6% respectively. Plants growing on Ebba valley slope indicate almost twice smaller values of <span class="hlt">ring</span> <span class="hlt">width</span> (41μm), and higher</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AIPC.1782c0001B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AIPC.1782c0001B"><span>An efficient algorithm for equal <span class="hlt">width</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bakodah, Huda. O.; Banaja, Mona. A.</p> <p>2016-10-01</p> <p>The new modification of Laplace Adomian decomposition method (ADM) to obtain numerical solution of the equal <span class="hlt">width</span> equation is presented. The performance of the method illustrated by solving some test examples of the problem. By computing the absolute error the results are found in good agreement with exact solution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24074073','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24074073"><span>Bounding the Higgs boson <span class="hlt">width</span> through interferometry.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dixon, Lance J; Li, Ye</p> <p>2013-09-13</p> <p>We study the change in the diphoton-invariant-mass distribution for Higgs boson decays to two photons, due to interference between the Higgs resonance in gluon fusion and the continuum background amplitude for gg→γγ. Previously, the apparent Higgs mass was found to shift by around 100 MeV in the standard model in the leading-order approximation, which may potentially be experimentally observable. We compute the next-to-leading-order QCD corrections to the apparent mass shift, which reduce it by about 40%. The apparent mass shift may provide a way to measure, or at least bound, the Higgs boson <span class="hlt">width</span> at the Large Hadron Collider through "interferometry." We investigate how the shift depends on the Higgs <span class="hlt">width</span>, in a model that maintains constant Higgs boson signal yields. At Higgs <span class="hlt">widths</span> above 30 MeV, the mass shift is over 200 MeV and increases with the square root of the <span class="hlt">width</span>. The apparent mass shift could be measured by comparing with the ZZ* channel, where the shift is much smaller. It might be possible to measure the shift more accurately by exploiting its strong dependence on the Higgs transverse momentum.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.4861Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.4861Y"><span>The ralationship between the Tamarix spp. <span class="hlt">growth</span> and lake level change in the Bosten Lake,northwest China</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ye, Mao; Hou, JiaWen</p> <p>2015-04-01</p> <p>Dendrochronology methods are used to analyze the characteristics of Tamarix spp. <span class="hlt">growth</span> in Bosten Lake. Based on the long-term annual and monthly data of lake level, this paper models the relationship between <span class="hlt">ring</span> <span class="hlt">width</span> of Tamarix spp. and lake level change. The sensitivity index is applied to determine the rational change range of lake level for protecting the Tamarix spp. <span class="hlt">growth</span>. The results show that :( 1) the annual change of lake level in Bosten Lake has tree evident stages from 1955 to 2012. The monthly change of lake level has two peak values and the seasonal change is not significant; (2) the average value of radical <span class="hlt">width</span> of Tamarix spp. is 3.39mm. With the increment of Tamarix spp. annual <span class="hlt">growth</span> , the average radical <span class="hlt">width</span> has a decreasing trend, which is similar to the annual change trend of lake level in the same years ;( 3) the response of the radical <span class="hlt">width</span> of Tamarix spp. to annual change of lake level is sensitive significantly. When the lake level is 1045.66m, the Sk value of radical <span class="hlt">width</span> of Tamarix spp. appears minimum .when the lake level is up to1046.27m, the Sk value is maximum. Thus the sensitivity level of radical <span class="hlt">width</span> of Tamarix spp. is 1045.66- 1046.27m which could be regarded as the rational lake level change range for protecting the Tamarix spp. <span class="hlt">growth</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFMPP31B1491V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFMPP31B1491V"><span>Seasonal, Inter-annual and Long Term Trends in the Element Composition of Tropical Tree <span class="hlt">Rings</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Verheyden, A.; Beeckman, H.; Andre, L.</p> <p>2008-12-01</p> <p>The inorganic composition of Rhizophora mucronata wood was studied on 11 stem discs collected from two mangrove forests in Kenya. The aim of this preliminary study was to assess if elements could be used as proxies of environmental and/or anthropogenic change. Earlywood and late wood were separated and analyzed on ICP-MS and ICP-OES. A remarkable synchronicity was found between <span class="hlt">ring</span> <span class="hlt">width</span> and Mg/Ca and Mn/Ca ratios, both of which have been used as soil pH proxies. However, there was also a negative correlation between Ca and <span class="hlt">ring</span> <span class="hlt">width</span>, indicating a dilution effect at higher <span class="hlt">growth</span> rates. The essential elements P and K were significantly higher in fast growing plantation trees, suggesting that these elements might be useful as nutrient proxies in mangrove wood. A high correlation was found between Ca and Sr in the wood, indicating that probably no differentiation is made by the tree during incorporation of these elements in the wood. Since Sr/Ca of seawater is related to salinity, we suggest that the Sr/Ca in the wood could be used as a salinity proxy for tree species growing in brackish waters. Finally, a high-resolution study was also conducted using LA-ICP-MS, which revealed a high spatial variability within one <span class="hlt">ring</span>. This high variability was the result of different concentrations in each wood cell type analyzed. The heavy metals (Cu, Zn, Pb and Cr), as well as Ba, had highest concentrations in the fibers and lowest in the vessels. On the other hand, B, Mn, Ca, P, and Sr were highest in the rays and vessels and lowest in the fibers, while Mg was the highest in the rays, but lowest in the vessels. The implications of these results for the use of trace elements to delimit chemical <span class="hlt">ring</span> boundaries in tropical trees will be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21388994','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21388994"><span>Browsing affects intra-<span class="hlt">ring</span> carbon allocation in species with contrasting wood anatomy.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Palacio, S; Paterson, E; Sim, A; Hester, A J; Millard, P</p> <p>2011-02-01</p> <p>Current knowledge on tree carbon (C) allocation to wood is particularly scarce in plants subjected to disturbance factors, such as browsing, which affects forest regeneration worldwide and has an impact on the C balance of trees. Furthermore, quantifying the degree to which tree <span class="hlt">rings</span> are formed from freshly assimilated vs. stored carbohydrates is highly relevant for our understanding of tree C allocation. We used (13)C labelling to quantify seasonal allocation of stored C to wood formation in two species with contrasting wood anatomy: Betula pubescens Ehrh. (diffuse-porous) and Quercus petraea [Matt.] Liebl. (<span class="hlt">ring</span>-porous). Clipping treatments (66% shoot removal, and unclipped) were applied to analyse the effect of browsing on C allocation into tree <span class="hlt">rings</span>, plus the effects on tree <span class="hlt">growth</span>, architecture, <span class="hlt">ring</span> <span class="hlt">width</span> and non-structural carbohydrates (NSCs). The relative contribution of stored C to wood formation was greater in the <span class="hlt">ring</span>-porous (55-70%) than in the diffuse-porous species (35-60%), although each species followed different seasonal trends. Clipping did not cause a significant depletion of C stores in either species. Nonetheless, a significant increase in the proportion of stored C allocated to earlywood <span class="hlt">growth</span> was observed in clipped birches, and this could be explained through changes in tree architecture after clipping. The size of C pools across tree species seems to be important in determining the variability of seasonal C allocation patterns to wood and their sensibility to disturbances such as browsing. Our results indicate that the observed changes in C allocation to earlywood in birch were not related to variations in the amount or concentration of NSC stores, but to changes in the seasonal availability of recently assimilated C caused by modifications in tree architecture after browsing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/6440173','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/6440173"><span>Storage <span class="hlt">ring</span> injection</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Burke, R.J.</p> <p>1980-01-01</p> <p>Some basic issues involved in injecting the beam into storage <span class="hlt">rings</span> with the principal parameters of those studied at the workshop have been considered. The main conclusion is that straightforward adjustments of the storage <span class="hlt">ring</span> parameters makes injection easy. The largest number of injected turns is fourteen, and the phase space dilution allowance seems adequate to ensure very small beam loss during injection. The adjustments also result in lower bending magnet fields, and high field superconducting magnets (e.g., 5 Tesla) are not necessary. The design changes do not necessarily affect the Keil-Schnell criterion for stability of the longitudinal microwave instability, although that criterion appears to be irrelevant. Because the beams are expected to be unstable, but with slow <span class="hlt">growth</span> rates, the vacuum chamber impedances required to give equal risetimes for the various designs are compared for systems posing various degrees of difficulty for injection. Finally, the impact of the parameters on cost is noted, and a system is considered that cuts the length of the linac in half by using doubly charged ions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24514525','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24514525"><span>Cavity mode-<span class="hlt">width</span> spectroscopy with widely tunable ultra narrow laser.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cygan, Agata; Lisak, Daniel; Morzyński, Piotr; Bober, Marcin; Zawada, Michał; Pazderski, Eugeniusz; Ciuryło, Roman</p> <p>2013-12-02</p> <p>We explore a cavity-enhanced spectroscopic technique based on determination of the absorbtion coefficient from direct measurement of spectral <span class="hlt">width</span> of the mode of the optical cavity filled with absorbing medium. This technique called here the cavity mode-<span class="hlt">width</span> spectroscopy (CMWS) is complementary to the cavity <span class="hlt">ring</span>-down spectroscopy (CRDS). While both these techniques use information on interaction time of the light with the cavity to determine absorption coefficient, the CMWS does not require to measure very fast signals at high absorption conditions. Instead the CMWS method require a very narrow line <span class="hlt">width</span> laser with precise frequency control. As an example a spectral line shape of P7 Q6 O₂ line from the B-band was measured with use of an ultra narrow laser system based on two phase-locked external cavity diode lasers (ECDL) having tunability of ± 20 GHz at wavelength range of 687 to 693 nm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20010005742','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20010005742"><span>BOREAS TE-5 Tree <span class="hlt">Ring</span> and Carbon Isotope Ratio Data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hall, Forrest G. (Editor); Curd, Shelaine (Editor); Ehleriinger, Jim; Brooks, J. Renee; Flanagan, Larry</p> <p>2000-01-01</p> <p>The BOREAS TE-5 team collected several data sets to investigate the vegetation-atmosphere CO2 and H2O exchange processes. These data include tree <span class="hlt">ring</span> <span class="hlt">widths</span> and cellulose carbon isotope data from coniferous trees collected at the BOREAS NSA and SSA in 1993 and 1994 by the BOREAS TE-5 team. <span class="hlt">Ring</span> <span class="hlt">width</span> data are provided for both Picea mariana and Pinus banksiana. The carbon isotope data are provided only for Pinus banksiana. The data are provided in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21399310','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21399310"><span>Size effects in Aharonov-Bohm graphene <span class="hlt">rings</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yan, Cong-Hua; Wei, Lian-Fu</p> <p>2010-07-28</p> <p>Aharonov-Bohm (AB) effects in mesoscopic metal <span class="hlt">rings</span> have been extensively studied. In this paper, we investigate these effects on the persistent currents (PCs) in a closed graphene <span class="hlt">ring</span> with broken time-reversal symmetry. A hard boundary condition is introduced to describe the Dirac electrons moving along such a <span class="hlt">ring</span>-shaped configuration, and then the induced persistent currents are numerically calculated. Differing from the properties of PCs revealed in the metal AB <span class="hlt">rings</span>, we show that the present PCs neither show the regular saw-tooth-like features nor present the odd-even symmetry of the electron number. More interestingly, we show that the energy difference between the two valleys and the amplitude of the oscillating PCs increase with the decrease (increase) of the radius (<span class="hlt">width</span>) of the graphene <span class="hlt">ring</span>. Our results imply that the AB effect and size-dependent PCs in <span class="hlt">ring</span>-shaped microstructures could be tested at room temperature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010JPCM...22C5503Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010JPCM...22C5503Y"><span>Size effects in Aharonov-Bohm graphene <span class="hlt">rings</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yan, Cong-Hua; Wei, Lian-Fu</p> <p>2010-07-01</p> <p>Aharonov-Bohm (AB) effects in mesoscopic metal <span class="hlt">rings</span> have been extensively studied. In this paper, we investigate these effects on the persistent currents (PCs) in a closed graphene <span class="hlt">ring</span> with broken time-reversal symmetry. A hard boundary condition is introduced to describe the Dirac electrons moving along such a <span class="hlt">ring</span>-shaped configuration, and then the induced persistent currents are numerically calculated. Differing from the properties of PCs revealed in the metal AB <span class="hlt">rings</span>, we show that the present PCs neither show the regular saw-tooth-like features nor present the odd-even symmetry of the electron number. More interestingly, we show that the energy difference between the two valleys and the amplitude of the oscillating PCs increase with the decrease (increase) of the radius (<span class="hlt">width</span>) of the graphene <span class="hlt">ring</span>. Our results imply that the AB effect and size-dependent PCs in <span class="hlt">ring</span>-shaped microstructures could be tested at room temperature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMPP43B1485D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMPP43B1485D"><span>Seasonal Climate Signals in Multiple Tree-<span class="hlt">Ring</span> Parameters: A Pilot Study of Pinus ponderosa in the Columbia River Basin</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dannenberg, M.; Wise, E. K.; Keung, J. H.</p> <p>2014-12-01</p> <p>Proxy-based reconstructions of past climate have played an integral role in assessments of historical climate change, and tree-<span class="hlt">ring</span> <span class="hlt">widths</span> (TRW) have a long history of use in this paleoclimate research due to their annual resolution, widespread availability, and sensitivity of <span class="hlt">growth</span> processes to variation in temperature and water availability. Increasingly, studies have shown that additional tree-<span class="hlt">ring</span> metrics—including earlywood and latewood <span class="hlt">widths</span> (EW and LW, respectively), maximum latewood density, and the intensity of reflected blue light from latewood (BI)—can provide additional information on seasonal climatic variability that is not present in TRW alone due to different processes that affect <span class="hlt">growth</span> in different parts of the growing season. Studies of these additional tree-<span class="hlt">ring</span> metrics highlight their utility in climate reconstructions, but to date they have mostly been limited to a few tree species and regions. Here, we extend the range of previous studies on alternative tree-<span class="hlt">ring</span> metrics by evaluating the seasonal climate signals in TRW, EW, LW, and BI of Pinus ponderosa at six semiarid sites surrounding the Columbia River basin in the U.S. Pacific Northwest (PNW). Cores from each site were cross-dated and EW, LW, and TRW were measured using standard dendrochronological procedures. BI was obtained using a high-resolution flatbed scanner and CooRecorder software. To evaluate the unique climate processes and seasonalities contributing to different dendrochronological metrics, monthly temperature and precipitation from each site were obtained from the PRISM climate model and were correlated with each of the tree-<span class="hlt">ring</span> metrics using the MATLAB program SEASCORR. We also evaluate the potential of using multiple tree-<span class="hlt">ring</span> metrics (rather than a single proxy) in reconstructions of precipitation in the PNW. Initial results suggest that 1) tree <span class="hlt">growth</span> at each site is water-limited but with substantial differences among the sites in the strength and seasonality of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25769337','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25769337"><span>Biophysical modelling of intra-<span class="hlt">ring</span> variations in tracheid features and wood density of Pinus pinaster trees exposed to seasonal droughts.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wilkinson, Sarah; Ogée, Jérôme; Domec, Jean-Christophe; Rayment, Mark; Wingate, Lisa</p> <p>2015-03-01</p> <p>Process-based models that link seasonally varying environmental signals to morphological features within tree <span class="hlt">rings</span> are essential tools to predict tree <span class="hlt">growth</span> response and commercially important wood quality traits under future climate scenarios. This study evaluated model portrayal of radial <span class="hlt">growth</span> and wood anatomy observations within a mature maritime pine (Pinus pinaster (L.) Aït.) stand exposed to seasonal droughts. Intra-annual variations in tracheid anatomy and wood density were identified through image analysis and X-ray densitometry on stem cores covering the <span class="hlt">growth</span> period 1999-2010. A cambial <span class="hlt">growth</span> model was integrated with modelled plant water status and sugar availability from the soil-plant-atmosphere transfer model MuSICA to generate estimates of cell number, cell volume, cell mass and wood density on a weekly time step. The model successfully predicted inter-annual variations in cell number, <span class="hlt">ring</span> <span class="hlt">width</span> and maximum wood density. The model was also able to predict the occurrence of special anatomical features such as intra-annual density fluctuations (IADFs) in <span class="hlt">growth</span> <span class="hlt">rings</span>. Since cell wall thickness remained surprisingly constant within and between <span class="hlt">growth</span> <span class="hlt">rings</span>, variations in wood density were primarily the result of variations in lumen diameter, both in the model and anatomical data. In the model, changes in plant water status were identified as the main driver of the IADFs through a direct effect on cell volume. The anatomy data also revealed that a trade-off existed between hydraulic safety and hydraulic efficiency. Although a simplified description of cambial physiology is presented, this integrated modelling approach shows potential value for identifying universal patterns of tree-<span class="hlt">ring</span> <span class="hlt">growth</span> and anatomical features over a broad climatic gradient. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMPP51A2264M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMPP51A2264M"><span>Testing for the Influence of Light Availability on Tree-<span class="hlt">Ring</span> Reconstructed Temperature at Sonora Pass, CA</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ma, L.; Stine, A.</p> <p>2015-12-01</p> <p>Tree-<span class="hlt">ring</span> <span class="hlt">width</span> and density near treeline tend to covary with local interannual temperature, motivating the use of such records to reconstruct past temperature variability. However, recent work has introduced the possibility of multiple environmental factors contributing to tree <span class="hlt">growth</span> in cold environments. We investigate the influence of small-scale light variability on tree-<span class="hlt">ring</span> based temperature reconstructions from a treeline ecotone. We establish an experimental plot near Sonora Pass in the California Sierra Nevada (38.32N, 119.64W; elev. 3130 m). This treeline environment is dominated by whitebark pine (Pinus albicaulis) growing as individuals and in stands, providing an opportunity to test the sensitivity of mean <span class="hlt">growth</span> rate and interannual variability to light availability. For each tree we quantify the local light environment using three approaches: (i.) geometrical estimates of shading from neighboring trees, (ii.) photographic estimates of shading from neighboring trees, and (iii.) geometric estimates of direct light availability resulting from aspect and local topography. Geometrical estimates of shading are made by mapping the relative position and crown dimensions of each tree in the plot in order to calculate a shading index that will be used to test hypotheses about the influence of shading on tree <span class="hlt">growth</span>. Photographic estimates of tree-level shading are created by taking hemispheric photographs at the crown edge of each tree and calculating the effects of neighboring trees on direct and diffuse light availability using the Gap Light Analyzer software. To quantify tree <span class="hlt">growth</span>, increment cores are collected from all trees in the plot to develop sub-chronologies of <span class="hlt">ring</span> records grouped by different light environments. We hypothesize that trees growing in open areas or at edge of stands, which experience little inter-tree competition, would likely produce <span class="hlt">ring</span> records more closely correlated with the temperature record; whereas trees growing in middle</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMPP33A2083L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMPP33A2083L"><span>Refining Climatic Interpretations of Lower Forest Border Bristlecone Pine Tree-<span class="hlt">Ring</span> Chronologies Over Recent Millennia</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Larson, E. R.; Wilding, T.; Salzer, M. W.</p> <p>2012-12-01</p> <p>High-resolution paleoclimatology has been enhanced by the development of many proxy records of past climate variability derived from annually-resolved tree-<span class="hlt">ring</span> <span class="hlt">widths</span>. Bristlecone pine (Pinus longaeva) from western North America provides a unique and particularly useful proxy record that is both annually resolved and can extend for millennia. One challenge in interpreting bristlecone pine <span class="hlt">ring-width</span> records is that <span class="hlt">ring</span> <span class="hlt">growth</span> can be influenced by both precipitation and temperature; we show that data from a separate species of pine improves understanding of these <span class="hlt">growth</span> factors. The Methuselah Walk chronology (MWK) from the White Mountains of southern California provides a continuous, annually-resolved time series that has been used to estimate variability in precipitation over the past 8000 years (Hughes and Graumlich 1996). The reconstruction fails to capture five of the ten driest years during the calibration period of 1930-1980, however, possibly due to the shifting influence of temperature on factors such as snow pack retention that affect tree <span class="hlt">growth</span> and that are important at this relatively high-elevation lower-forest border (~2800 m). The MWK reconstruction thus likely overestimates moisture availability over the reconstruction period. To improve interpretation of the MWK chronology we developed a tree-<span class="hlt">ring</span> chronology from piñon pine trees (Pinus monophylla) growing in the same mountain range but approximately 400 m below MWK and therefore less likely to be influenced by temperature variability. The piñon living tree chronology (GVP) spans over five centuries, and cross sections collected from remnants predate AD 900, indicating the potential for developing a millennial-scale piñon chronology for use in conjunction with MWK. Tree <span class="hlt">growth</span> at GVP was positively correlated with spring and summer precipitation, negatively correlated with summer temperatures over the instrumental record, and tracked precipitation during three of five drought years missed by</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012IJBm...56....1K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012IJBm...56....1K"><span>Tree <span class="hlt">rings</span> of Scots pine ( Pinus sylvestris L.) as a source of information about past climate in northern Poland</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Koprowski, Marcin; Przybylak, Rajmund; Zielski, Andrzej; Pospieszyńska, Aleksandra</p> <p>2012-01-01</p> <p>Scots pine ( Pinus sylvestris) is a very common tree in Polish forests, and therefore was widely used as timber. A relatively large amount of available wood allowed a long-term chronology to be built up and used as a source of information about past climate. The analysis of reconstructed indexed values of mean temperature in 51-year moving intervals allowed the recognition of the coldest periods in the years 1207-1346, 1383-1425, 1455-1482, 1533-1574, 1627-1646, and 1694-1785. The analysis of extreme wide and narrow <span class="hlt">rings</span> forms a complementary method of examining climatic data within tree <span class="hlt">rings</span>. The tree <span class="hlt">ring</span> <span class="hlt">widths</span>, early wood and late wood <span class="hlt">widths</span> of 16 samples were assessed during the period 1581-1676. The most apparent effect is noted in the dry summer of 1616. According to previous research and our findings, temperature from February to March seems to be one of the most stable climatic factors which influenced pine <span class="hlt">growth</span> in Poland. Correlation coefficients in the calibration and validation procedure gave promising results for temperature reconstruction from the pine chronology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AtmRe.151..259G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AtmRe.151..259G"><span>Tree <span class="hlt">rings</span> as an indicator of atmospheric pollutant deposition to subalpine spruce forests in the Sudetes (Southern Poland)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Godek, Michał; Sobik, Mieczysław; Błaś, Marek; Polkowska, Żaneta; Owczarek, Piotr; Bokwa, Anita</p> <p>2015-01-01</p> <p>In spite of their moderate altitude (1000-1600 m a.s.l.), the Western Sudety Mountains belong to areas with the most efficient fog precipitation in Europe. Intense industrial activity in the area of windward western foothills caused an exceptional intensification of atmospheric pollutant deposition via precipitation and fog to take place since the 1950s. In the second half of the 1970s a massive spruce forest dieback began affecting around 42% of coniferous forest in the Polish part of the Sudety Mountains. As the result of emission abatement in the region, gradual improvement of forest health status has been observed in the last decade. In October 2010 there were 70 dendrochronological samples collected from Norway spruce (Picea abies) stems at 7 different locations using an increment borer. It was documented for six sites that lowest annual <span class="hlt">growth</span> rates took place between the early eighties and the early nineties which coincides with the highest pollutant deposition rates. Only one site representing the lowest parts of leeward slope showed gradual decrease of tree <span class="hlt">rings</span> as a result of increasing tree age rather than due to an increase in ecological stress conditions. Tree <span class="hlt">ring</span> <span class="hlt">widths</span> were then compared with spatial distribution of fog frequency in the Western Sudety Mountains. The achieved results document a strongly negative dependence of tree <span class="hlt">ring</span> <span class="hlt">widths</span> on fog deposition rates. Spruce forest ecosystems have an ability to respond quickly to both negative and positive stimuli, related to increasing and decreasing environmental contamination.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21174127','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21174127"><span>Tree <span class="hlt">rings</span> of Scots pine (Pinus sylvestris L.) as a source of information about past climate in northern Poland.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Koprowski, Marcin; Przybylak, Rajmund; Zielski, Andrzej; Pospieszyńska, Aleksandra</p> <p>2012-01-01</p> <p>Scots pine (Pinus sylvestris) is a very common tree in Polish forests, and therefore was widely used as timber. A relatively large amount of available wood allowed a long-term chronology to be built up and used as a source of information about past climate. The analysis of reconstructed indexed values of mean temperature in 51-year moving intervals allowed the recognition of the coldest periods in the years 1207-1346, 1383-1425, 1455-1482, 1533-1574, 1627-1646, and 1694-1785. The analysis of extreme wide and narrow <span class="hlt">rings</span> forms a complementary method of examining climatic data within tree <span class="hlt">rings</span>. The tree <span class="hlt">ring</span> <span class="hlt">widths</span>, early wood and late wood <span class="hlt">widths</span> of 16 samples were assessed during the period 1581-1676. The most apparent effect is noted in the dry summer of 1616. According to previous research and our findings, temperature from February to March seems to be one of the most stable climatic factors which influenced pine <span class="hlt">growth</span> in Poland. Correlation coefficients in the calibration and validation procedure gave promising results for temperature reconstruction from the pine chronology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23316689','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23316689"><span>New star on the stage: amount of ray parenchyma in tree <span class="hlt">rings</span> shows a link to climate.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Olano, José Miguel; Arzac, Alberto; García-Cervigón, Ana I; von Arx, Georg; Rozas, Vicente</p> <p>2013-04-01</p> <p>Tree-<span class="hlt">ring</span> anatomy reflects the year-by-year impact of environmental factors on tree <span class="hlt">growth</span>. Up to now, research in this field has mainly focused on the hydraulic architecture, with ray parenchyma neglected despite the growing recognition of its relevance for xylem function. Our aim was to address this gap by exploring the potential of the annual patterns of xylem parenchyma as a climate proxy. We constructed <span class="hlt">ring-width</span> and ray-parenchyma chronologies from 1965 to 2004 for 20 Juniperus thurifera trees growing in a Mediterranean continental climate. Chronologies were related to climate records by means of correlation, multiple regression and partial correlation analyses. Ray parenchyma responded to climatic conditions at critical stages during the xylogenetic process; namely, at the end of the previous year's xylogenesis (October) and at the onset of earlywood (May) and latewood formation (August). Ray parenchyma-based chronologies have potential to complement <span class="hlt">ring-width</span> chronologies as a tool for climate reconstructions. Furthermore, medium- and low-frequency signals in the variation of ray parenchyma may improve our understanding of how trees respond to environmental fluctuations and to global change.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22842114','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22842114"><span>Characterisation of ferromagnetic <span class="hlt">rings</span> for Zernike phase plates using the Aharonov-Bohm effect.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Edgcombe, C J; Ionescu, A; Loudon, J C; Blackburn, A M; Kurebayashi, H; Barnes, C H W</p> <p>2012-09-01</p> <p>Holographic measurements on magnetised thin-film cobalt <span class="hlt">rings</span> have demonstrated both onion and vortex states of magnetisation. For a <span class="hlt">ring</span> in the vortex state, the difference between phases of electron paths that pass through the <span class="hlt">ring</span> and those that travel outside it was found to agree very well with Aharonov-Bohm theory within measurement error. Thus the magnetic flux in thin-film <span class="hlt">rings</span> of ferromagnetic material can provide the phase shift required for phase plates in transmission electron microscopy. When a <span class="hlt">ring</span> of this type is used as a phase plate, scattered electrons will be intercepted over a radial range similar to the <span class="hlt">ring</span> <span class="hlt">width</span>. A cobalt <span class="hlt">ring</span> of thickness 20 nm can produce a phase difference of π/2 from a <span class="hlt">width</span> of just under 30 nm, suggesting that the range of radial interception for this type of phase plate can be correspondingly small.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010JPhCS.238a2047K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010JPhCS.238a2047K"><span>Directional variance analysis of annual <span class="hlt">rings</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kumpulainen, P.; Marjanen, K.</p> <p>2010-07-01</p> <p>The wood quality measurement methods are of increasing importance in the wood industry. The goal is to produce more high quality products with higher marketing value than is produced today. One of the key factors for increasing the market value is to provide better measurements for increased information to support the decisions made later in the product chain. Strength and stiffness are important properties of the wood. They are related to mean annual <span class="hlt">ring</span> <span class="hlt">width</span> and its deviation. These indicators can be estimated from images taken from the log ends by two-dimensional power spectrum analysis. The spectrum analysis has been used successfully for images of pine. However, the annual <span class="hlt">rings</span> in birch, for example are less distinguishable and the basic spectrum analysis method does not give reliable results. A novel method for local log end variance analysis based on Radon-transform is proposed. The directions and the positions of the annual <span class="hlt">rings</span> can be estimated from local minimum and maximum variance estimates. Applying the spectrum analysis on the maximum local variance estimate instead of the original image produces more reliable estimate of the annual <span class="hlt">ring</span> <span class="hlt">width</span>. The proposed method is not limited to log end analysis only. It is usable in other two-dimensional random signal and texture analysis tasks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA00701&hterms=Halo&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DHalo','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA00701&hterms=Halo&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DHalo"><span>Jupiter's Main <span class="hlt">Ring/Ring</span> Halo</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1997-01-01</p> <p>A mosaic of four images taken through the clear filter (610 nanometers) of the solid state imaging (CCD) system aboard NASA's Galileo spacecraft on November 8, 1996, at a resolution of approximately 46 kilometers (28.5 miles) per picture element (pixel) along Jupiter's <span class="hlt">rings</span>. Because the spacecraft was only about 0.5 degrees above the <span class="hlt">ring</span> plane, the image is highly foreshortened in the vertical direction. The images were obtained when Galileo was in Jupiter's shadow, peering back toward the Sun; the <span class="hlt">ring</span> was approximately 2.3 million kilometers (1.4 million miles) away. The arc on the far right of the image is produced when sunlight is scattered by small particles comprising Jupiter's upper atmospheric haze. The <span class="hlt">ring</span> also efficiently scatters light, indicating that much of its brightness is due to particles that are microns or less in diameter. Such small particles are believed to have human-scale lifetimes, i.e., very brief compared to the solar system's age.<p/>Jupiter's <span class="hlt">ring</span> system is composed of three parts - - a flat main <span class="hlt">ring</span>, a lenticular halo interior to the main <span class="hlt">ring</span>, and the gossamer <span class="hlt">ring</span>, outside the main <span class="hlt">ring</span>. The near and far arms of Jupiter's main <span class="hlt">ring</span> extend horizontally across the mosaic, joining together at the <span class="hlt">ring</span>'s ansa, on the figure's far left side. The near arm of the <span class="hlt">ring</span> appears to be abruptly truncated close to the planet, at the point where it passes into Jupiter's shadow. Some radial structure is barely visible across the <span class="hlt">ring</span>'s ansa (top image). A faint mist of particles can be seen above and below the main <span class="hlt">rings</span>. This vertically extended 'halo' is unusual in planetary <span class="hlt">rings</span>, and is probably caused by electromagnetic forces pushing the smallest grains out of the <span class="hlt">ring</span> plane. Because of shadowing, the halo is not visible close to Jupiter in the lower right part of the mosaic. To accentuate faint features in the bottom image of the <span class="hlt">ring</span> halo, different brightnesses are shown through color. Brightest features are white or yellow and the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA00701&hterms=halo&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dhalo','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA00701&hterms=halo&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dhalo"><span>Jupiter's Main <span class="hlt">Ring/Ring</span> Halo</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1997-01-01</p> <p>A mosaic of four images taken through the clear filter (610 nanometers) of the solid state imaging (CCD) system aboard NASA's Galileo spacecraft on November 8, 1996, at a resolution of approximately 46 kilometers (28.5 miles) per picture element (pixel) along Jupiter's <span class="hlt">rings</span>. Because the spacecraft was only about 0.5 degrees above the <span class="hlt">ring</span> plane, the image is highly foreshortened in the vertical direction. The images were obtained when Galileo was in Jupiter's shadow, peering back toward the Sun; the <span class="hlt">ring</span> was approximately 2.3 million kilometers (1.4 million miles) away. The arc on the far right of the image is produced when sunlight is scattered by small particles comprising Jupiter's upper atmospheric haze. The <span class="hlt">ring</span> also efficiently scatters light, indicating that much of its brightness is due to particles that are microns or less in diameter. Such small particles are believed to have human-scale lifetimes, i.e., very brief compared to the solar system's age.<p/>Jupiter's <span class="hlt">ring</span> system is composed of three parts - - a flat main <span class="hlt">ring</span>, a lenticular halo interior to the main <span class="hlt">ring</span>, and the gossamer <span class="hlt">ring</span>, outside the main <span class="hlt">ring</span>. The near and far arms of Jupiter's main <span class="hlt">ring</span> extend horizontally across the mosaic, joining together at the <span class="hlt">ring</span>'s ansa, on the figure's far left side. The near arm of the <span class="hlt">ring</span> appears to be abruptly truncated close to the planet, at the point where it passes into Jupiter's shadow. Some radial structure is barely visible across the <span class="hlt">ring</span>'s ansa (top image). A faint mist of particles can be seen above and below the main <span class="hlt">rings</span>. This vertically extended 'halo' is unusual in planetary <span class="hlt">rings</span>, and is probably caused by electromagnetic forces pushing the smallest grains out of the <span class="hlt">ring</span> plane. Because of shadowing, the halo is not visible close to Jupiter in the lower right part of the mosaic. To accentuate faint features in the bottom image of the <span class="hlt">ring</span> halo, different brightnesses are shown through color. Brightest features are white or yellow and the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.2549V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.2549V"><span>Dendrochronology and lakes: using tree-<span class="hlt">rings</span> of alder to reconstruct lake levels</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>van der Maaten, Ernst; Buras, Allan; Scharnweber, Tobias; Simard, Sonia; Kaiser, Knut; Lorenz, Sebastian; van der Maaten-Theunissen, Marieke; Wilmking, Martin</p> <p>2014-05-01</p> <p> Lake District, northeastern Germany. Tree-<span class="hlt">ring</span> data were collected from black alder forests surrounding the lakes 'Tiefer See', 'Drewitzer See' and 'Großer Fürstenseer See'. At all research sites, increment cores were extracted from at least 15 trees (2 cores per tree) using an increment borer. In the tree-<span class="hlt">ring</span> lab DendroGreif, these cores were prepared and annual tree-<span class="hlt">ring</span> <span class="hlt">widths</span> were measured. Thereafter, site-specific tree-<span class="hlt">ring</span> chronologies were built using established detrending and standardization procedures. Preliminary results show that the <span class="hlt">growth</span> of alder reacts upon water level fluctuations. We visually and statistically compare the developed tree-<span class="hlt">ring</span> chronologies with historical lake-level records, and retrospectively model lake levels. Findings will be presented while critically reflecting upon the quality of these reconstructions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011WRR....47.7516B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011WRR....47.7516B"><span>Spring flood reconstruction from continuous and discrete tree <span class="hlt">ring</span> series</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Boucher, ÉTienne; Ouarda, Taha B. M. J.; BéGin, Yves; Nicault, Antoine</p> <p>2011-07-01</p> <p>This study proposes a method to reconstruct past spring flood discharge from continuous and discrete tree <span class="hlt">ring</span> chronologies, since both have their respective strengths and weaknesses in northern environments. <span class="hlt">Ring</span> <span class="hlt">width</span> or density series provide uninterrupted records that are indirectly linked to regional discharge through a concomitant effect of climate on tree <span class="hlt">growth</span> and streamflow. Conversely, discrete event chronologies constitute conspicuous records of past high water levels since they are constructed from trees that are directly damaged by the flood. However, the uncertainty of discrete series increases toward the past, and their relationships with spring discharge are often nonlinear. To take advantage of these two sources of information, we introduce a new transfer model technique on the basis of generalized additive model (GAM) theory. The incorporation of discrete predictors and the evaluation of the robustness of the nonlinear relationships are assessed using a jackknife procedure. We exemplify our approach in a reconstruction of May water supplies to the Caniapiscau hydroelectric reservoir in northern Quebec, Canada. We used earlywood density measurements as continuous variables and ice-scar dates around Lake Montausier in the James Bay area as a discrete variable. Strong calibration (0.57 < 0.61 < 0.75) and validation (0.27 < 0.44 < 0.58) R2 statistics were obtained, thus highlighting the usefulness of the model. Our reconstruction suggests that, since ˜1965, spring floods have become more intense and variable in comparison with the last 150 years. We argue that a similar procedure can be used in each case where discrete and continuous tree <span class="hlt">ring</span> proxies are used together to reconstruct past spring floods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AcO....37...99I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AcO....37...99I"><span>Initial period of sexual maturity determines the greater <span class="hlt">growth</span> rate of male over female in the dioecious tree Juniperus communis subsp. communis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Iszkuło, Grzegorz; Boratyński, Adam</p> <p>2011-03-01</p> <p>Dioecious species are a very interesting object of study because of predicted differences between male and female individuals. Most dioecious species have a higher reproductive effort in female individuals in comparison with males. The object of this study was common juniper ( Juniperus communis subsp. communis), dioecious shrubs or small trees. This study examined differences in radial <span class="hlt">growth</span> rate between male and female individuals and the effect of climatic factors on tree-<span class="hlt">ring</span> <span class="hlt">width</span> in this species. Wood samples were taken from 30 trees (15 females and 15 males) and subjected to the standard procedure of dendrochronological dating. Females had lower <span class="hlt">growth</span> rates than males after the age of 17 years. The greatest differences between genders in <span class="hlt">growth</span> rate were observed between 17 and 25 years. After 26 years, male tree-<span class="hlt">rings</span> were still wider, but the differences were much smaller. The differentiation of tree-<span class="hlt">ring</span> <span class="hlt">width</span> between males and females probably started when the female trees reached sexual maturity and started to produce seed cones. Differences between sexes in tree-<span class="hlt">ring</span> <span class="hlt">width</span> were noticed also in their reaction to climatic conditions. When compared to males, female individuals tended to be more sensitive to low temperature and low precipitation. This sensitivity of dioecious species could be one reason for their greater susceptibility to extinction in times of progressive climatic changes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26142450','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26142450"><span>Functional adjustments of xylem anatomy to climatic variability: insights from long-term Ilex aquifolium tree-<span class="hlt">ring</span> series.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rita, Angelo; Cherubini, Paolo; Leonardi, Stefano; Todaro, Luigi; Borghetti, Marco</p> <p>2015-08-01</p> <p>The present study assessed the effects of climatic conditions on radial <span class="hlt">growth</span> and functional anatomical traits, including <span class="hlt">ring</span> <span class="hlt">width</span>, vessel size, vessel frequency and derived variables, i.e., potential hydraulic conductivity and xylem vulnerability to cavitation in Ilex aquifolium L. trees using long-term tree-<span class="hlt">ring</span> time series obtained at two climatically contrasting sites, one mesic site in Switzerland (CH) and one drought-prone site in Italy (ITA). Relationships were explored by examining different xylem traits, and point pattern analysis was applied to investigate vessel clustering. We also used generalized additive models and bootstrap correlation functions to describe temperature and precipitation effects. Results indicated modified radial <span class="hlt">growth</span> and xylem anatomy in trees over the last century; in particular, vessel frequency increased markedly at both sites in recent years, and all xylem traits examined, with the exception of xylem cavitation vulnerability, were higher at the CH mesic compared with the ITA drought site. A significant vessel clustering was observed at the ITA site, which could contribute to an enhanced tolerance to drought-induced embolism. Flat and negative relationships between vessel size and <span class="hlt">ring</span> <span class="hlt">width</span> were observed, suggesting carbon was not allocated to radial <span class="hlt">growth</span> under conditions which favored stem water conduction. Finally, in most cases results indicated that climatic conditions influenced functional anatomical traits more substantially than tree radial <span class="hlt">growth</span>, suggesting a crucial role of functional xylem anatomy in plant acclimation to future climatic conditions. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PhRvC..96a5205H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PhRvC..96a5205H"><span>K- nuclear states: Binding energies and <span class="hlt">widths</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hrtánková, J.; Mareš, J.</p> <p>2017-07-01</p> <p>K- optical potentials relevant to calculations of K- nuclear quasibound states were developed within several chiral meson-baryon coupled-channels interaction models. The applied models yield quite different K- binding energies and <span class="hlt">widths</span>. Then the K- multinucleon interactions were incorporated by a phenomenological optical potential fitted recently to kaonic atom data. Though the applied K- interaction models differ significantly in the K-N subthreshold region, our self-consistent calculations of kaonic nuclei across the periodic table lead to conclusions valid quite generally. Due to K- multinucleon absorption in the nuclear medium, the calculated <span class="hlt">widths</span> of K- nuclear states are sizable, ΓK-≥90 MeV, and exceed substantially their binding energies in all considered nuclei.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012QSRv...34....1S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012QSRv...34....1S"><span>Tree-<span class="hlt">ring</span> analysis of ancient baldcypress trees and subfossil wood</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stahle, David W.; Burnette, Dorian J.; Villanueva, Jose; Cerano, Julian; Fye, Falko K.; Griffin, R. Daniel; Cleaveland, Malcolm K.; Stahle, Daniel K.; Edmondson, Jesse R.; Wolff, Kathryn P.</p> <p>2012-02-01</p> <p>Ancient baldcypress trees found in wetland and riverine environments have been used to develop a network of exactly dated annual <span class="hlt">ring-width</span> chronologies extending from the southeastern United States, across Mexico, and into western Guatemala. These chronologies are sensitive to growing season precipitation in spite of frequently flooded site conditions, and have been used to reconstruct moisture levels the southeastern United States and Mexico for over 1000 years. The El Nino/Southern Oscillation (ENSO) is a major influence on the climate reconstructions derived from these baldcypress chronologies, especially in Mexico where some of the most extreme reconstructed droughts occurred during El Nino events. In the Southeast, the ENSO influence on climate and tree <span class="hlt">growth</span> changes sign from spring to summer, and this change in dynamical forcing is recorded by sub-seasonal chronologies of earlywood and latewood <span class="hlt">width</span>. Most existing baldcypress chronologies have been extended with tree-<span class="hlt">ring</span> data from "subfossil" wood recovered from surface and submerged deposits. Well-preserved subfossil logs have also been recovered in quantity from buried deposits of great age, and may permit development of long continuously dated Holocene chronologies and discontinuous "floating" Pleistocene chronologies. The extensive subfossil baldcypress swamp discovered 6 m below the streets of Washington D.C. was overrun by a transgression of the Potomac estuary, possibly during the previous super interglacial (marine OIS 5e), and provides direct evidence for one potential impact of unmitigated anthropogenic warming and sea level rise.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21062034','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21062034"><span><span class="hlt">Ring</span> formation in self-focusing of electromagnetic beams in plasmas</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Faisal, M.; Mishra, S. K.; Verma, M. P.; Sodha, M. S.</p> <p>2007-10-15</p> <p>This article presents a paraxial theory of <span class="hlt">ring</span> formation as an initially Gaussian beam propagates in a nonlinear plasma, characterized by significant collisional or ponderomotive nonlinearity. Regions in the axial irradiance-(beam <span class="hlt">width</span>){sup -2} space, for which the <span class="hlt">ring</span> formation occurs and the paraxial theory is valid, have been characterized; for typical points in these regions the dependence of the beam <span class="hlt">width</span> parameter and the radial distribution of irradiance on the distance has been specifically investigated and discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009LNCS.5687..686R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009LNCS.5687..686R"><span>Testing Computability by <span class="hlt">Width</span> Two OBDDs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ron, Dana; Tsur, Gilad</p> <p></p> <p>Property testing is concerned with deciding whether an object (e.g. a graph or a function) has a certain property or is “far” (for some definition of far) from every object with that property. In this paper we give lower and upper bounds for testing functions for the property of being computable by a read-once <span class="hlt">width</span>-2 Ordered Binary Decision Diagram (OBDD), also known as a branching program, where the order of the variables is known. <span class="hlt">Width</span>-2 OBDDs generalize two classes of functions that have been studied in the context of property testing - linear functions (over GF(2)) and monomials. In both these cases membership can be tested in time that is linear in 1/ɛ. Interestingly, unlike either of these classes, in which the query complexity of the testing algorithm does not depend on the number, n, of variables in the tested function, we show that (one-sided error) testing for computability by a <span class="hlt">width</span>-2 OBDD requires Ω(log(n)) queries, and give an algorithm (with one-sided error) that tests for this property and performs tilde{O}(log(n)/ɛ) queries.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16601188','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16601188"><span>New dust belts of Uranus: one <span class="hlt">ring</span>, two <span class="hlt">ring</span>, red <span class="hlt">ring</span>, blue <span class="hlt">ring</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>de Pater, Imke; Hammel, Heidi B; Gibbard, Seran G; Showalter, Mark R</p> <p>2006-04-07</p> <p>We compared near-infrared observations of the recently discovered outer <span class="hlt">rings</span> of Uranus with Hubble Space Telescope results. We find that the inner <span class="hlt">ring</span>, R/2003 U 2, is red, whereas the outer <span class="hlt">ring</span>, R/2003 U 1, is very blue. Blue is an unusual color for <span class="hlt">rings</span>; Saturn's enigmatic E <span class="hlt">ring</span> is the only other known example. By analogy to the E <span class="hlt">ring</span>, R/2003 U 1 is probably produced by impacts into the embedded moon Mab, which apparently orbits at a location where nongravitational perturbations favor the survival and spreading of submicron-sized dust. R/2003 U 2 more closely resembles Saturn's G <span class="hlt">ring</span>, which is red, a typical color for dusty <span class="hlt">rings</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA12641.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA12641.html"><span><span class="hlt">Rings</span> Through Atmosphere</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2010-05-26</p> <p>NASA Cassini spacecraft looks toward the limb of Saturn and, on the right of this image, views part of the <span class="hlt">rings</span> through the planet atmosphere. Saturn atmosphere can distort the view of the <span class="hlt">rings</span> from some angles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA15505.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA15505.html"><span>Wavy, Wiggly <span class="hlt">Ring</span></span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2012-04-23</p> <p>The constant change in Saturn wavy, wiggly F <span class="hlt">ring</span> is on display in this image obtained by NASA Cassini spacecraft. The image shows a view looking directly down onto the <span class="hlt">ring</span> with the planet removed from the center.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA01940.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA01940.html"><span>Saturn <span class="hlt">Rings</span> in Infrared</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2006-10-11</p> <p>This mosaic of Saturn <span class="hlt">rings</span> was acquired by NASA Cassini visual and infrared mapping spectrometer instrument on Sept. 15, 2006, while the spacecraft was in the shadow of the planet looking back towards the <span class="hlt">rings</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA08869.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA08869.html"><span>The Inner <span class="hlt">Rings</span></span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2007-02-01</p> <p>The Cassini spacecraft looks toward the innermost region of Saturn <span class="hlt">rings</span>, capturing from right to left the C and B <span class="hlt">rings</span>. The dark, inner edge of the Cassini Division is just visible in the lower left corner</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA02293&hterms=Makeup&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DMakeup','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA02293&hterms=Makeup&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DMakeup"><span>Saturn's F-<span class="hlt">Ring</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2000-01-01</p> <p>This narrow-angle camera image of Saturn's F <span class="hlt">Ring</span> was taken through the Clear filter while at a distance of 6.9 million km from Saturn on 8 November 1980. The brightness variations of this tightly-constrained <span class="hlt">ring</span> shown here indicate that the <span class="hlt">ring</span> is less uniform in makeup than the larger <span class="hlt">rings</span>. JPL managed the Voyager Project for NASA's Office of Space Science</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA02293&hterms=makeup&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dmakeup','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA02293&hterms=makeup&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dmakeup"><span>Saturn's F-<span class="hlt">Ring</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2000-01-01</p> <p>This narrow-angle camera image of Saturn's F <span class="hlt">Ring</span> was taken through the Clear filter while at a distance of 6.9 million km from Saturn on 8 November 1980. The brightness variations of this tightly-constrained <span class="hlt">ring</span> shown here indicate that the <span class="hlt">ring</span> is less uniform in makeup than the larger <span class="hlt">rings</span>. JPL managed the Voyager Project for NASA's Office of Space Science</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25239517','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25239517"><span>Do variations in leaf phenology affect radial <span class="hlt">growth</span> variations in Fagus sylvatica?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Čufar, Katarina; De Luis, Martin; Prislan, Peter; Gričar, Jožica; Črepinšek, Zalika; Merela, Maks; Kajfež-Bogataj, Lučka</p> <p>2015-08-01</p> <p>We used a dendrochronological and leaf phenology network of European beech (Fagus sylvatica) in Slovenia, a transitional area between Mediterranean, Alpine and continental climatic regimes, for the period 1955-2007 to test whether year to year variations in leaf unfolding and canopy duration (i.e. time between leaf unfolding and colouring) influence radial <span class="hlt">growth</span> (annual xylem production and tree <span class="hlt">ring</span> <span class="hlt">widths</span>) and if such influences are more pronounced at higher altitudes. We showed that variability in leaf phenology has no significant effect on variations in radial <span class="hlt">growth</span>. The results are consistent in the entire region, irrespective of the climatic regime or altitude, although previous studies have shown that leaf phenology and tree <span class="hlt">ring</span> variation depend on altitude. The lack of relationship between year to year variability in leaf phenology and radial <span class="hlt">growth</span> may suggest that earlier leaf unfolding--as observed in a previous study--probably does not cause increased tree <span class="hlt">growth</span> rates in beech in Slovenia.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015IJBm...59.1127C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015IJBm...59.1127C"><span>Do variations in leaf phenology affect radial <span class="hlt">growth</span> variations in Fagus sylvatica?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Čufar, Katarina; De Luis, Martin; Prislan, Peter; Gričar, Jožica; Črepinšek, Zalika; Merela, Maks; Kajfež-Bogataj, Lučka</p> <p>2015-08-01</p> <p>We used a dendrochronological and leaf phenology network of European beech ( Fagus sylvatica) in Slovenia, a transitional area between Mediterranean, Alpine and continental climatic regimes, for the period 1955-2007 to test whether year to year variations in leaf unfolding and canopy duration (i.e. time between leaf unfolding and colouring) influence radial <span class="hlt">growth</span> (annual xylem production and tree <span class="hlt">ring</span> <span class="hlt">widths</span>) and if such influences are more pronounced at higher altitudes. We showed that variability in leaf phenology has no significant effect on variations in radial <span class="hlt">growth</span>. The results are consistent in the entire region, irrespective of the climatic regime or altitude, although previous studies have shown that leaf phenology and tree <span class="hlt">ring</span> variation depend on altitude. The lack of relationship between year to year variability in leaf phenology and radial <span class="hlt">growth</span> may suggest that earlier leaf unfolding—as observed in a previous study—probably does not cause increased tree <span class="hlt">growth</span> rates in beech in Slovenia.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/9408703','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/9408703"><span>Fertility regulation in nursing women. IX. Contraceptive performance, duration of lactation, infant <span class="hlt">growth</span>, and bleeding patterns during use of progesterone vaginal <span class="hlt">rings</span>, progestin-only pills, Norplant implants, and Copper T 380-A intrauterine devices.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Díaz, S; Zepeda, A; Maturana, X; Reyes, M V; Miranda, P; Casado, M E; Peralta, O; Croxatto, H B</p> <p>1997-10-01</p> <p>This study evaluated the performance of progesterone vaginal <span class="hlt">rings</span> (n = 187), progestin-only pills (n = 117), Norplant implants (n = 120), and Copper T 380-A intrauterine devices (n = 122) in lactating women. Contraceptive efficacy, bleeding pattern, and influence of the method upon breastfeeding duration and infant <span class="hlt">growth</span> were compared with those of untreated women (n = 236) who relied on lactational infertility. Participants were healthy, 18 to 38 years, had had a normal delivery, and were intending to breastfeed for as long as possible. Contraceptives were initiated at day 57 +/- 3 postpartum. Results are reported for the first year of use. All methods were highly effective, with pregnancy rates below 1%. None affected breastfeeding performance or the rate of infant <span class="hlt">growth</span>. Users of the progestin-only methods experienced a period of lactational amenorrhea 4 to 5 months longer than did users of Copper T or untreated women. More than half of the women in each contraceptive group reported a bleeding in the first month after treatment initiation, which was not considered in the calculation of the duration of amenorrhea. Prolonged or frequent bleedings were infrequent. The proportion of bleedings lasting more than 10 days ranged from 0 in the progestin-only pills group to 7% in the Norplant implants group. The four methods, initiated around the eighth postpartum week, provided effective contraception with no negative effects upon lactation or infant <span class="hlt">growth</span> and without the bleeding problems associated with their use in nonlactating women.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21202773','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21202773"><span>Modules over hereditary <span class="hlt">rings</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Tuganbaev, A A</p> <p>1998-04-30</p> <p>Let A be a hereditary Noetherian prime <span class="hlt">ring</span> that is not right primitive. A complete description of {pi}-injective A-modules is obtained. Conditions under which the classical <span class="hlt">ring</span> of quotients of A is a {pi}-projective A-module are determined. A criterion for a right hereditary right Noetherian prime <span class="hlt">ring</span> to be serial is obtained.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=Uranus&id=EJ166551','ERIC'); return false;" href="https://eric.ed.gov/?q=Uranus&id=EJ166551"><span><span class="hlt">Rings</span> Around Uranus</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Maran, Stephen P.</p> <p>1977-01-01</p> <p>Events leading up to the discovery of the <span class="hlt">rings</span> of Uranus are described. The methods used and the logic behind the methods are explained. Data collected to prove the existence of the <span class="hlt">rings</span> are outlined and theories concerning the presence of planetary <span class="hlt">rings</span> are presented. (AJ)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/EJ166551.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/EJ166551.pdf"><span><span class="hlt">Rings</span> Around Uranus</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Maran, Stephen P.</p> <p>1977-01-01</p> <p>Events leading up to the discovery of the <span class="hlt">rings</span> of Uranus are described. The methods used and the logic behind the methods are explained. Data collected to prove the existence of the <span class="hlt">rings</span> are outlined and theories concerning the presence of planetary <span class="hlt">rings</span> are presented. (AJ)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA12512.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA12512.html"><span>Eyeing the E <span class="hlt">Ring</span></span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2009-12-24</p> <p>NASA Cassini spacecraft takes a look at Saturn diffuse E <span class="hlt">ring</span> which is formed from icy material spewing out of the south pole of the moon Enceladus. The E <span class="hlt">ring</span> is seen nearly edge-on from slightly above the northern side of Saturn <span class="hlt">ring</span> plane.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Nitrogen&pg=3&id=EJ827419','ERIC'); return false;" href="http://eric.ed.gov/?q=Nitrogen&pg=3&id=EJ827419"><span>The Jumping <span class="hlt">Ring</span> Experiment</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Baylie, M.; Ford, P. J.; Mathlin, G. P.; Palmer, C.</p> <p>2009-01-01</p> <p>The jumping <span class="hlt">ring</span> experiment has become central to liquid nitrogen shows given as part of the outreach and open day activities carried out within the University of Bath. The basic principles of the experiment are described as well as the effect of changing the geometry of the <span class="hlt">rings</span> and their metallurgical state. In general, aluminium <span class="hlt">rings</span> are…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=aluminium&id=EJ827419','ERIC'); return false;" href="https://eric.ed.gov/?q=aluminium&id=EJ827419"><span>The Jumping <span class="hlt">Ring</span> Experiment</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Baylie, M.; Ford, P. J.; Mathlin, G. P.; Palmer, C.</p> <p>2009-01-01</p> <p>The jumping <span class="hlt">ring</span> experiment has become central to liquid nitrogen shows given as part of the outreach and open day activities carried out within the University of Bath. The basic principles of the experiment are described as well as the effect of changing the geometry of the <span class="hlt">rings</span> and their metallurgical state. In general, aluminium <span class="hlt">rings</span> are…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA17150.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA17150.html"><span>Dusty D <span class="hlt">Ring</span></span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2014-02-24</p> <p>Saturn D <span class="hlt">ring</span> is easy to overlook since it trapped between the brighter C <span class="hlt">ring</span> and the planet itself. In this view from NASA Cassini spacecraft, all that can be seen of the D <span class="hlt">ring</span> is the faint and narrow arc as it stretches from top right of the ima</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=304266','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=304266"><span>On certain Hecke <span class="hlt">rings</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Evens, Sam; Bressler, Paul</p> <p>1987-01-01</p> <p>We examine <span class="hlt">rings</span> that embed into the smash product of the group algebra of the Weyl group with the field of meromorphic functions on the Cartan subalgebra and are generated by elements that satisfy braid relations. We prove that every such <span class="hlt">ring</span> is isomorphic to either the Hecke algebra, the nil Hecke <span class="hlt">ring</span>, or the group algebra of the Weyl group. PMID:16593804</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27882284','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27882284"><span>Soft normed <span class="hlt">rings</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Uluçay, Vakkas; Şahin, Mehmet; Olgun, Necati</p> <p>2016-01-01</p> <p>Molodtsov introduced the concept of soft sets, which can be seen as a new mathematical tool for dealing with uncertainty. In this paper, we initiate the study of soft normed <span class="hlt">rings</span> by soft set theory. The notions of soft normed <span class="hlt">rings</span>, soft normed ideals, soft complete normed <span class="hlt">rings</span> are introduced and also several related properties and examples are given.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMPP41C1411F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMPP41C1411F"><span>Climate and flow variation revealed in tree <span class="hlt">rings</span> of riparian cottonwood, western North Dakota, USA</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Friedman, J. M.; Edmondson, J. R.; Meko, D. M.; Touchan, R.; Griffin, E. R.; Zhou, H.</p> <p>2014-12-01</p> <p>In the western Great Plains, where old upland trees are scarce, <span class="hlt">rings</span> of riparian trees provide an important opportunity for reconstructing past river flow and climate. We present data from 489 plains cottonwood (Populus deltoides ssp. monilifera) trees along the Little Missouri River in western North Dakota. The trees are in randomly selected flood-plain locations within the North and South units of Theodore Roosevelt National Park. The two sites are separated by 160 river km. The Little Missouri watershed contains foothills but no mountains, and most annual high flows result from snowmelt in March or April. Cores were collected and processed using standard dendrochronological methods. The effect of tree age was removed from the chronology using a single relation for the site as a whole (age-curve standardization), which preserves century-scale variation. Trees were as old as 371 years. Given that cottonwood establishment depends upon channel migration, abundant establishment from 1864-1891 at both sites suggests that one or more large floods occurred prior to this period. At the North Unit, establishment continued at a lower rate during the next century, but upstream at the South Unit, tree establishment was greatly curtailed after the 1800s. Comparison of General Land Office Maps from 1907 to recent satellite imagery confirms that channel migration in the last century was much greater within the North Unit, a difference caused in part by a downstream increase in flood amplification by ice jamming. <span class="hlt">Ring</span> <span class="hlt">widths</span> show that even on the flood plain riparian trees were chronically drought stressed. At both sites <span class="hlt">growth</span> was strongly positively correlated with flow and precipitation and weakly negatively correlated with temperature. <span class="hlt">Growth</span> was most strongly correlated with flow and precipitation in April-July, which is consistent with dendrometer-band measurements showing <span class="hlt">growth</span> cessation in August. Whereas cottonwood establishment decreased in the 1900s, <span class="hlt">ring</span> <span class="hlt">widths</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/30661','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/30661"><span>Some observations of wood density and anatomical properties in a Douglas-fir sample with suppressed <span class="hlt">growth</span></span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>J.Y. Zhu; David W. Vahey; C. Tim Scott</p> <p>2008-01-01</p> <p>This study used <span class="hlt">ring</span> <span class="hlt">width</span> correlations to examine the effects of tree-<span class="hlt">growth</span> suppression on within-tree local wood density and tracheid anatomical properties. A wood core sample was taken from a 70-yr-old Douglas-fir that grew under various degrees of suppression in a natural forest setting. SilviScan and an imaging technique were used to obtain wood density and...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/1016189','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/1016189"><span>Recent <span class="hlt">growth</span> of conifer species of western North America: Assessing spatial patterns of radial <span class="hlt">growth</span> trends</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>McKenzie, D.; Hessl, Amy E.; Peterson, D.L.</p> <p>2001-01-01</p> <p>We explored spatial patterns of low-frequency variability in radial tree <span class="hlt">growth</span> among western North American conifer species and identified predictors of the variability in these patterns. Using 185 sites from the International Tree-<span class="hlt">Ring</span> Data Bank, each of which contained 10a??60 raw <span class="hlt">ring-width</span> series, we rebuilt two chronologies for each site, using two conservative methods designed to retain any low-frequency variability associated with recent environmental change. We used factor analysis to identify regional low-frequency patterns in site chronologies and estimated the slope of the <span class="hlt">growth</span> trend since 1850 at each site from a combination of linear regression and time-series techniques. This slope was the response variable in a regression-tree model to predict the effects of environmental gradients and species-level differences on <span class="hlt">growth</span> trends. <span class="hlt">Growth</span> patterns at 27 sites from the American Southwest were consistent with quasi-periodic patterns of drought. Either 12 or 32 of the 185 sites demonstrated patterns of increasing <span class="hlt">growth</span> between 1850 and 1980 A.D., depending on the standardization technique used. Pronounced <span class="hlt">growth</span> increases were associated with high-elevation sites (above 3000 m) and high-latitude sites in maritime climates. Future research focused on these high-elevation and high-latitude sites should address the precise mechanisms responsible for increased 20th century <span class="hlt">growth</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017RMxAC..49Q.157S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017RMxAC..49Q.157S"><span>The behavior of the planetary <span class="hlt">rings</span> under the Kozai Mechanism</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sucerquia, M. A.; Ramírez, C. V.; Zuluaga, J. I.</p> <p>2017-07-01</p> <p><span class="hlt">Rings</span> are one of the main feature of almost all giant planets in the Solar System. Even though thousands of exoplanets have been discovered to date, no evidence of exoplanetary <span class="hlt">rings</span> have been found despite the effort made in the development and enhancing of techniques and methods for direct or indirect detection. In the transit of a <span class="hlt">ringed</span> planet, the dynamic of the <span class="hlt">ring</span> itself could play a meaningful role due to the so called Kozai Mechanism (KM) acting on each particle of it. When some specific initial conditions of the <span class="hlt">ring</span> are fulfilled (as a <span class="hlt">ring</span> inclination greater than ˜ 39°), KM generates short periodic changes in the inclination and eccentricity of each particle, leading to a meaningful characteristic collective behavior of the <span class="hlt">ring</span>: it changes its <span class="hlt">width</span>, inclination and optical depth. These changes induce periodic variations on the eclipsed area of the parent star, generating slight changes in the observed transit signal. Under this mechanism, light curves depths and shapes oscillate according to the fluctuations of the <span class="hlt">ring</span>. To show this effect we have performed numerical simulations of the dynamic of a system of particles to asses the <span class="hlt">ring</span> inclination and <span class="hlt">width</span> variations over time. We have calculated the expected variations in the transit depth and finally, we have estimated the effect on the light curve of a hypothetical <span class="hlt">ringed</span> exoplanet affected by the KM. The detection of this effect could be used as an alternative method to detect/confirm exoplanetary <span class="hlt">rings</span>, and also it could be considered as a way to explain anomalous light curves patterns of exoplanets, as the case of KIC 8462852 star.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010PhRvL.105d8102O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010PhRvL.105d8102O"><span>Kinetics of Myosin Node Aggregation into a Contractile <span class="hlt">Ring</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ojkic, Nikola; Vavylonis, Dimitrios</p> <p>2010-07-01</p> <p>We study a stochastic aggregation model for the assembly of the contractile <span class="hlt">ring</span> from a broad band of nodes during cytokinesis in fission yeast. We found that bands of nodes condense into <span class="hlt">rings</span> when the range of node interactions is larger than the <span class="hlt">width</span> of the band. Wide bands are unstable to clump formation due to Poisson density fluctuations. We derive expressions for node kinetics and times for <span class="hlt">ring</span> vs clump formation and test them using numerical simulations. These results suggest clump formation mechanisms in mutant cells.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110023607','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110023607"><span>Artifacts for Calibration of Submicron <span class="hlt">Width</span> Measurements</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Grunthaner, Frank; Grunthaner, Paula; Bryson, Charles, III</p> <p>2003-01-01</p> <p>Artifacts that are fabricated with the help of molecular-beam epitaxy (MBE) are undergoing development for use as dimensional calibration standards with submicron <span class="hlt">widths</span>. Such standards are needed for calibrating instruments (principally, scanning electron microscopes and scanning probe microscopes) for measuring the <span class="hlt">widths</span> of features in advanced integrated circuits. Dimensional calibration standards fabricated by an older process that involves lithography and etching of trenches in (110) surfaces of single-crystal silicon are generally reproducible to within dimensional tolerances of about 15 nm. It is anticipated that when the artifacts of the present type are fully developed, their critical dimensions will be reproducible to within 1 nm. These artifacts are expected to find increasing use in the semiconductor-device and integrated- circuit industries as the <span class="hlt">width</span> tolerances on semiconductor devices shrink to a few nanometers during the next few years. Unlike in the older process, one does not rely on lithography and etching to define the critical dimensions. Instead, one relies on the inherent smoothness and flatness of MBE layers deposited under controlled conditions and defines the critical dimensions as the thicknesses of such layers. An artifact of the present type is fabricated in two stages (see figure): In the first stage, a multilayer epitaxial wafer is grown on a very flat substrate. In the second stage, the wafer is cleaved to expose the layers, then the exposed layers are differentially etched (taking advantage of large differences between the etch rates of the different epitaxial layer materials). The resulting structure includes narrow and well-defined trenches and a shelf with thicknesses determined by the thicknesses of the epitaxial layers from which they were etched. Eventually, it should be possible to add a third fabrication stage in which durable, electronically inert artifacts could be replicated in diamondlike carbon from a master made by</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19812546','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19812546"><span>Saturn's largest <span class="hlt">ring</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Verbiscer, Anne J; Skrutskie, Michael F; Hamilton, Douglas P</p> <p>2009-10-22</p> <p>Most planetary <span class="hlt">rings</span> in the Solar System lie within a few radii of their host body, because at these distances gravitational accelerations inhibit satellite formation. The best known exceptions are Jupiter's gossamer <span class="hlt">rings</span> and Saturn's E <span class="hlt">ring</span>, broad sheets of dust that extend outward until they fade from view at five to ten planetary radii. Source satellites continuously supply the dust, which is subsequently lost in collisions or by radial transport. Here we report that Saturn has an enormous <span class="hlt">ring</span> associated with its outer moon Phoebe, extending from at least 128R(S) to 207R(S) (Saturn's radius R(S) is 60,330 km). The <span class="hlt">ring</span>'s vertical thickness of 40R(S) matches the range of vertical motion of Phoebe along its orbit. Dynamical considerations argue that these <span class="hlt">ring</span> particles span the Saturnian system from the main <span class="hlt">rings</span> to the edges of interplanetary space. The <span class="hlt">ring</span>'s normal optical depth of approximately 2 x 10(-8) is comparable to that of Jupiter's faintest gossamer <span class="hlt">ring</span>, although its particle number density is several hundred times smaller. Repeated impacts on Phoebe, from both interplanetary and circumplanetary particle populations, probably keep the <span class="hlt">ring</span> populated with material. <span class="hlt">Ring</span> particles smaller than centimetres in size slowly migrate inward and many of them ultimately strike the dark leading face of Iapetus.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=281758','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=281758"><span>Climate and red spruce <span class="hlt">growth</span> and decline in the northern Appalachians</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Johnson, A. H.; Cook, E. R.; Siccama, T. G.</p> <p>1988-01-01</p> <p>Between the mid-1960s and mid-1980s, red spruce (Picea rubens Sarg.) died at unusual rates on the mountains of New York and western New England. We determined the relationship between standardized tree <span class="hlt">ring</span> <span class="hlt">widths</span> and monthly climate data for calibration and verification periods from 1856 to 1981 and found that after about 1960, there was a distinct shift in the temperature variables related to standardized <span class="hlt">ring</span> <span class="hlt">widths</span> in vigorous spruce. The beginning of widespread spruce mortality, regionwide <span class="hlt">growth</span> decreases, and the shift in response to climate in the early 1960s corresponds to the onset of a decade of unusually cold winters and several consecutive years when severe winter damage was noted across the Northeast in this species. We suggest that the episodes of winter damage are an important initiating and synchronizing factor in the red spruce decline. PMID:16593962</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1985ASSL..119...59M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1985ASSL..119...59M"><span>On the solar dust <span class="hlt">ring(s</span>)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mukai, T.</p> <p></p> <p>Based on a mechanism to form the solar dust <span class="hlt">ring</span>, it is proved that the observed peak in infrared F-corona cannot be explained by silicate type grains alone. Preliminary analysis on the recent infrared data of the F-corona by Maihara et al. (1984) has suggested that the <span class="hlt">ring</span> particles have different physical properties compared with the dust grains, which produce the background F-corona.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/22179','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/22179"><span><span class="hlt">Ring</span> Shake in Eastern Hemlock: Frequency and Relationship to Tree Attributes</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>John E. Baumgras; Paul E. Sendak; David L. Sonderman; David L. Sonderman</p> <p>2000-01-01</p> <p><span class="hlt">Ring</span> shake is a barrier to improved utilization of eastern hemlock, an important component of the total softwood timber resource in the Eastern United States and Canada. <span class="hlt">Ring</span> shake is the lengthwise separation of wood that occurs between and parallel to <span class="hlt">growth</span> <span class="hlt">rings</span>, diminishing lumber yields and values. Evaluating the potential for <span class="hlt">ring</span> shake is essential to improving...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/14696','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/14696"><span><span class="hlt">Ring</span> shake in eastern hemlock: frequency and relationship to tree attributes</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>John E. Baumgras; Paul E. Sendak; David L. Sonderman</p> <p>2000-01-01</p> <p><span class="hlt">Ring</span> shake is a barrier to improved utilization of eastern hemlock, an important component of the total softwood timber resource in the Eastern United States and Canada. <span class="hlt">Ring</span> shake is the lengthwise separation of wood that occurs between and parallel to <span class="hlt">growth</span> <span class="hlt">rings</span>, diminishing lumber yields and values. Evaluating the potential for <span class="hlt">ring</span> shake is essential to improving...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011GPC....75..143Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011GPC....75..143Q"><span>Regional extreme climate events on the northeastern Tibetan Plateau since AD 1450 inferred from tree <span class="hlt">rings</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Qin, Chun; Yang, Bao; Bräuning, Achim; Sonechkin, Dmitry M.; Huang, Kai</p> <p>2011-02-01</p> <p>Qilian juniper ( Juniperus przewalskii Kom.) is a widely distributed tree species growing on south-facing slopes in the northeastern Tibetan Plateau in arid northwestern China. We established a tree-<span class="hlt">ring</span> <span class="hlt">width</span> network based on two new chronologies and four previously published chronologies. Correlation and response function analyses demonstrate that precipitation positively influences radial <span class="hlt">growth</span>. Despite of minor differences in local climate-<span class="hlt">growth</span> relations, precipitation for the annual window between previous July and current June shows consistent positive correlations with <span class="hlt">ring</span> <span class="hlt">width</span> at all study sites. Similar to the so called 'pointer year' approach, 'anomalous' <span class="hlt">growth</span> years were defined to extract extreme climate events for the period AD 1450-2006. We defined a dryness-wetness grade series with five grades of climate events inferred from anomalous year analysis. During the last 50 years, the frequency of wet events increased and that of drought events decreased noticeably, implying that the probability of occurrence of dry years in the northeastern Tibetan Plateau will further decrease in the future if regional warming continues. Combining our proxy records with a historical dryness-wetness record from eastern China, we mapped dryness-wetness patterns over large parts of China. By analyzing the atmospheric pressure patterns at the 850 hPa level over China for selected extreme event years, we found that the confluence of cold and hot air is a precondition for a flood event in the northeastern Tibetan Plateau. Thus, a counter-clockwise atmospheric circulation centered in south of Lake Baikal only occurs in flood event years.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19830056903&hterms=saturn+ring+formation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dsaturn%2Bring%2Bformation','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19830056903&hterms=saturn+ring+formation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dsaturn%2Bring%2Bformation"><span>Electrostatic discharges in Saturn's B-<span class="hlt">ring</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Warwick, J. W.; Romig, J. H.; Evans, D. R.</p> <p>1983-01-01</p> <p>The Voyager observations of electrical discharges in Saturn's <span class="hlt">rings</span> strongly support earlier speculations on the role played by electrostatics, magnetic fields, and lightning phenomena in the primitive solar system. They also suggest conditions then by direct analogy rather than by extrapolating backwards through time from conditions now. The observed discharges show a pronounced 10h periodicity, which suggests a source in Keplerian orbit at 1.80 + or - 0.01 Saturn radii. In that region, the B <span class="hlt">ring</span> is thicker than optical depth 1.8 for about 5,000 km. At 1.805 + or - 0.001 Saturn radii, however, the <span class="hlt">ring</span> is virtually transparent for a gap of <span class="hlt">width</span> 200 m. It is concluded that a small satellite orbits Saturn at that radius and clears the gap. The gap edges must prevent diffusive filling of the gap by fine material which is especially abundant at this position in the <span class="hlt">rings</span> and would otherwise destroy the gap in minutes. The discharges represent the satellite's interaction with the outer edge of the gap. Spoke formation may involve the interaction of <span class="hlt">ring</span> material in the vicinity of the gap.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1812240Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1812240Z"><span>Early and Mid-Holocene Climate Variability - A Multi-Proxy Approach from Multi-Millennial Tree <span class="hlt">Ring</span> Records</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ziehmer, Malin Michelle; Nicolussi, Kurt; Schlüchter, Christian; Leuenberger, Markus</p> <p>2016-04-01</p> <p>Most reconstructions of Holocene climate variability in the Alps are based on low-frequency archives such as glacier and tree line fluctuations. However; recent finds of wood remains in glacier forefields in the Alps reveal a unique high-frequency archive allowing climate reconstruction over the entire Holocene. The evolution of Holocene climate can be reconstructed by using a multi-proxy approach combining tree <span class="hlt">ring</span> <span class="hlt">width</span> and multiple stable isotope chronologies by establishing highly resolved stable isotope records from calendar-dated wood which covers the past 9000 years b2k. Therefore, we collected samples in the Alps covering a large SW-NE transect, primarily in glacier forefields but also in peat bogs and small lakes. The multiple sample locations allow the analysis of climatic conditions along a climatic gradient characterized by the change from an Atlantic to a more continental climate. Subsequently, tree <span class="hlt">ring</span> <span class="hlt">widths</span> are measured and samples are calendrically dated by means of tree <span class="hlt">ring</span> analysis. Due to the large amount of samples for stable isotope analysis (> 8000 samples to cover the entire Holocene by guaranteeing a sample replication of 4 samples per time unit of 5 years), dated wood samples are separated into 5-year tree <span class="hlt">ring</span> blocks. These blocks are sliced and the cellulose is extracted after a standardized procedure and crushed by ultrasonic homogenization. In order to establish multi-proxy records, the stable isotopes of carbon, oxygen and hydrogen are simultaneously measured. Both the 5-year tree <span class="hlt">ring</span> <span class="hlt">width</span> and multiple stable isotope series offer new insights into the Early and Mid-Holocene climate and its variability in the Alps. The stable isotope records reveal interesting low-frequency variability. But they also display expected offsets caused by the measurement of individual trees revealing effects of sampling site, tree species and <span class="hlt">growth</span> trend. These effects offer an additional insight into the tree <span class="hlt">growth</span> and stand behavior of single</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SPIE10224E..1LD','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SPIE10224E..1LD"><span>3D simulation of silicon micro-<span class="hlt">ring</span> resonator with Comsol</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Degtyarev, S. A.; Podlipnov, V. V.; Verma, Payal; Khonina, S. N.</p> <p>2016-12-01</p> <p>In this paper we provide 3d full-vector static electromagnetic simulation of silicon micro-<span class="hlt">ring</span> resonator operating. We show that geometrical and scalar approaches are not sufficiently accurate for calculating resonator parameters. Quite strong dependence of <span class="hlt">ring</span> resonator radius on waveguide <span class="hlt">width</span> is revealed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhRvE..94f2203O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhRvE..94f2203O"><span>Comparing the locking threshold for <span class="hlt">rings</span> and chains of oscillators</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ottino-Löffler, Bertrand; Strogatz, Steven H.</p> <p>2016-12-01</p> <p>We present a case study of how topology can affect synchronization. Specifically, we consider arrays of phase oscillators coupled in a <span class="hlt">ring</span> or a chain topology. Each <span class="hlt">ring</span> is perfectly matched to a chain with the same initial conditions and the same random natural frequencies. The only difference is their boundary conditions: periodic for a <span class="hlt">ring</span> and open for a chain. For both topologies, stable phase-locked states exist if and only if the spread or "<span class="hlt">width</span>" of the natural frequencies is smaller than a critical value called the locking threshold (which depends on the boundary conditions and the particular realization of the frequencies). The central question is whether a <span class="hlt">ring</span> synchronizes more readily than a chain. We show that it usually does, but not always. Rigorous bounds are derived for the ratio between the locking thresholds of a <span class="hlt">ring</span> and its matched chain, for a variant of the Kuramoto model that also includes a wider family of models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28173593','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28173593"><span>A heat wave during leaf expansion severely reduces productivity and modifies seasonal <span class="hlt">growth</span> patterns in a northern hardwood forest.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Stangler, Dominik Florian; Hamann, Andreas; Kahle, Hans-Peter; Spiecker, Heinrich; Mäkelä, Annikki</p> <p>2017-01-31</p> <p>A useful approach to monitor tree response to climate change and environmental extremes is the recording of long-term time series of stem radial variations obtained with precision dendrometers. Here, we study the impact of environmental stress on seasonal <span class="hlt">growth</span> dynamics and productivity of yellow birch (Betula alleghaniensis Britton) and sugar maple (Acer saccharum Marsh.) in the Great Lakes, St Lawrence forest region of Ontario. Specifically, we research the effects of a spring heat wave in 2010, and a summer drought in 2012 that occurred during the 2005–14 study period. We evaluated both <span class="hlt">growth</span> phenology (onset, cessation, duration of radial <span class="hlt">growth</span>, time of maximum daily <span class="hlt">growth</span> rate) and productivity (monthly and seasonal average <span class="hlt">growth</span> rates, maximum daily <span class="hlt">growth</span> rate, tree-<span class="hlt">ring</span> <span class="hlt">width</span>) and tested for differences and interactions among species and years. Productivity of sugar maple was drastically compromised by a 3-day spring heat wave in 2010 as indicated by low <span class="hlt">growth</span> rates, very early <span class="hlt">growth</span> cessation and a lagged <span class="hlt">growth</span> onset in the following year. Sugar maple also responded more sensitively than yellow birch to a prolonged drought period in July 2012, but final tree-<span class="hlt">ring</span> <span class="hlt">width</span> was not significantly reduced due to positive responses to above-average temperatures in the preceding spring. We conclude that sugar maple, a species that currently dominates northern hardwood forests, is vulnerable to heat wave disturbances during leaf expansion, which might occur more frequently under anticipated climate change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14.9104M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14.9104M"><span>The Structure of Saturn's F <span class="hlt">Ring</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Murray, C. D.; Attree, N. O.; Cooper, N. J.; Williams, G. A.</p> <p>2012-04-01</p> <p>In stark contrast to the ordered regularity of the planet's main <span class="hlt">rings</span>, Cassini images of Saturn's F <span class="hlt">ring</span> show a diversity of structures on a variety of scales. The <span class="hlt">ring</span> is located ~3000km beyond the edge of the A <span class="hlt">ring</span> and Cassini ISS images reveal a core (radial <span class="hlt">width</span> ~50km) with localised radial distortions (~50km), as well as occasional spiral strands that can extend to ~200km on either side. High-resolution images also show discrete structures on smaller scales (~10km) in addition to several types of clumps in or around the core and the strands. Despite this the F <span class="hlt">ring</span> can still be modelled as a uniformly precessing, eccentric, inclined <span class="hlt">ring</span> suggesting that it has sufficient mass for the effects of self-gravity or collisions to be important in maintaining this configuration. The perturbing effect of the nearby satellite Prometheus is now well understood (Murray et al., 2005) as is its role in producing clumps of material which then interact with the <span class="hlt">ring</span> and strands (Beurle et al., 2010). The production of the largest strands is linked to collisions between the <span class="hlt">ring</span>'s core and the object S/2004 S 6 (Murray et al., 2008) although additional objects may be involved. Such collisions produce "jets" of material that subsequently undergo Keplerian shear to produce the spiral strands. Cassini images have now provided direct evidence for the existence of a population of small objects (radius <1km) colliding with the <span class="hlt">ring</span>. The impact velocities are ~ 5 m/s implying a source of objects with orbits similar to that of the F <span class="hlt">ring</span>; this is consistent with what might be expected for objects formed in the core and perturbed by Prometheus. It is now possible to understand the morphology and dynamic nature of the F <span class="hlt">ring</span> as being due to the gravitational and collisional effects of a variety of nearby objects, ranging in size from Prometheus (mean radius ~40km) down to sub-km objects orbiting close to the core.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/865303','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/865303"><span>Pulse <span class="hlt">width</span> modulation inverter with battery charger</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Slicker, James M.</p> <p>1985-01-01</p> <p>An inverter is connected between a source of DC power and a three-phase AC induction motor, and a microprocessor-based circuit controls the inverter using pulse <span class="hlt">width</span> modulation techniques. In the disclosed method of pulse <span class="hlt">width</span> modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .theta., where .theta. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands for electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a "flyback" DC-DC converter circuit for recharging the battery.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18850895','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18850895"><span>Finite <span class="hlt">width</span> of quasistatic shear bands.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jagla, E A</p> <p>2008-08-01</p> <p>I study the average deformation rate of an amorphous material submitted to an external uniform shear strain rate, in the geometry known as the split-bottom configuration. The material is described using a stochastic model of plasticity at a mesoscopic scale. A shear band is observed to start at the split point at the bottom, and widen progressively towards the surface. In a two-dimensional geometry the average statistical properties of the shear band look similar to those of the directed polymer model. In particular, the surface <span class="hlt">width</span> of the shear band is found to scale with the system height H as H;{alpha} with alpha=0.68+/-0.02 . In more realistic three-dimensional simulations the exponent changes to alpha=0.60+/-0.02 and the bulk profile of the <span class="hlt">width</span> of the shear band is closer to a quarter of a circle, as it was observed to be the case in recent simulations of granular materials.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080005914','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080005914"><span>Pulse <span class="hlt">width</span> modulation inverter with battery charger</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Slicker, James M. (Inventor)</p> <p>1985-01-01</p> <p>An inverter is connected between a source of DC power and a three-phase AC induction motor, and a microprocessor-based circuit controls the inverter using pulse <span class="hlt">width</span> modulation techniques. In the disclosed method of pulse <span class="hlt">width</span> modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .theta., where .theta. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands for electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a flyback DC-DC converter circuit for recharging the battery.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27505755','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27505755"><span>Optical antennas with sinusoidal modulation in <span class="hlt">width</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dikken, Dirk Jan; Segerink, Frans B; Korterik, Jeroen P; Pfaff, Stefan S; Prangsma, Jord C; Herek, Jennifer L</p> <p>2016-08-08</p> <p>Small metal structures sustaining plasmon resonances in the optical regime are of great interest due to their large scattering cross sections and ability to concentrate light to subwavelength volumes. In this paper, we study the dipolar plasmon resonances of optical antennas with a constant volume and a sinusoidal modulation in <span class="hlt">width</span>. We experimentally show that by changing the phase of the <span class="hlt">width</span>-modulation, with a small 10 nm modulation amplitude, the resonance shifts over 160 nm. Using simulations we show how this simple design can create resonance shifts greater than 600 nm. The versatility of this design is further shown by creating asymmetric structures with two different modulation amplitudes, which we experimentally and numerically show to give rise to two resonances. Our results on both the symmetric and asymmetric antennas show the capability to control the localization of the fields outside the antenna, while still maintaining the freedom to change the antenna resonance wavelength. The antenna design we tested combines a large spectral tunability with a small footprint: all the antenna dimensions are factor 7 to 13 smaller than the wavelength, and hold potential as a design element in meta-surfaces for beam shaping.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AAS...22730802M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AAS...22730802M"><span>Investigating Starburst Galaxy Emission Line Equivalent <span class="hlt">Widths</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Meskhidze, Helen; Richardson, Chris T.</p> <p>2016-01-01</p> <p>Modeling star forming galaxies with spectral synthesis codes allows us to study the gas conditions and excitation mechanisms that are necessary to reproduce high ionization emission lines in both local and high-z galaxies. Our study uses the locally optimally-emitting clouds model to develop an atlas of starburst galaxy emission line equivalent <span class="hlt">widths</span>. Specifically, we address the following question: What physical conditions are necessary to produce strong high ionization emission lines assuming photoionization via starlight? Here we present the results of our photoionization simulations: an atlas spanning 15 orders of magnitude in ionizing flux and 10 orders of magnitude in hydrogen density that tracks over 150 emission lines ranging from the UV to the near IR. Each simulation grid contains ~1.5x104 photoionization models calculated by supplying a spectral energy distribution, grain content, and chemical abundances. Specifically, we will be discussing the effects on the emission line equivalent <span class="hlt">widths</span> of varying the metallicity of the cloud, Z = 0.2 Z⊙ to Z = 5.0 Z⊙, and varying the star-formation history, using the instantaneous and continuous evolution tracks and the newly released Starburst99 Geneva rotation tracks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/10374982','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/10374982"><span>Finite beam-<span class="hlt">width</span> ray model for geometric spectral broadening.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hoskins, P R; Fish, P J; Pye, S D; Anderson, T</p> <p>1999-03-01</p> <p>The purpose of the study was to compare measured spectral <span class="hlt">width</span> and maximum frequency with that predicted from ray models of geometric spectral broadening. Zero and finite beam-<span class="hlt">width</span> models were used. Spectral data were acquired from a string phantom using two commonly-used linear array systems. Beam <span class="hlt">width</span> and Doppler aperture sizes were measured using a needle hydrophone. The results showed that the experimentally measured data agreed best with the finite beam-<span class="hlt">width</span> model. The zero beam-<span class="hlt">width</span> model was in error by up to 50% for calculated spectral <span class="hlt">width</span>, and up to 10% for maximum frequency. It is concluded that spectral <span class="hlt">width</span> and maximum frequency are best calculated using the finite beam-<span class="hlt">width</span> model, and that ultrasound manufacturers could improve the variation in spectral broadening measured at different locations on a single machine by adjusting the aperture size to give a constant subtended angle and beam <span class="hlt">width</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012ThApC.107..519Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012ThApC.107..519Y"><span>Eigen analysis of tree-<span class="hlt">ring</span> records: part 3, taking heteroscedasticity and sampling effects into consideration</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Bao; Sonechkin, Dmitry M.; Datsenko, Nina M.; Ivashchenko, Nadezda N.; Liu, Jingjing; Qin, Chun</p> <p>2012-02-01</p> <p>This paper reports on the further development of a new technique for standardization of tree-<span class="hlt">ring</span> records called the eigen analysis of tree-<span class="hlt">ring</span> records. The data are from the same sample set of 56 long-lived Qilian junipers ( Sabina przewalskii Kom.) from the Dulan region in western China as was used in our previous paper (Yang et al. 2011b). To assess the heteroscedasticity of individual record deviations from the sample set regional curve (RC), we tested five different definitions of those deviations. Direct computations of eigenvectors of all relevant intrarecord covariation matrices turned out to be greatly affected by observational and computational noise; an analytic approximation of these vectors was therefore desirable. The Bessel function of the first kind and the zero order proved suitable for such an approximation, especially because the deviations were defined via subtraction of the RC from raw <span class="hlt">ring</span> <span class="hlt">width</span> records. Exclusion of the contributions of the first segment of the Bessel approximation, corresponding to the extremely large first eigenvalue, rendered individual record deviations from RC homoscedastic. Therefore, the routine Fourier basis became applicable to extract climate-dependent components of the residual deviations. A Fourier expansion of the Dulan chronology revealed the quasi-200-year-long solar activity cycle to be the main factor affecting Dulan tree <span class="hlt">growth</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E3069S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E3069S"><span>Dust and Planetary <span class="hlt">Rings</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Siddiqui, Muddassir</p> <p></p> <p>ABSTRACT Space is not empty it has comic radiations (CMBR), dust etc. Cosmic dust is that type of dust which is composed of particles in space which vary from few molecules to 0.1micro metres in size. This type of dust is made up of heavier atoms born in the heart of stars and supernova. Mainly it contains dust grains and when these dust grains starts compacting then it turns to dense clouds, planetary <span class="hlt">ring</span> dust and circumstellar dust. Dust grains are mainly silicate particles. Dust plays a major role in our solar system, for example in zodiacal light, Saturn's B <span class="hlt">ring</span> spokes, planetary <span class="hlt">rings</span> at Jovian planets and comets. Observations and measurements of cosmic dust in different regions of universe provide an important insight into the Universe's recycling processes. Astronomers consider dust in its most recycled state. Cosmic dust have radiative properties by which they can be detected. Cosmic dusts are classified as intergalactic dusts, interstellar dusts and planetary <span class="hlt">rings</span>. A planetary <span class="hlt">ring</span> is a <span class="hlt">ring</span> of cosmic dust and other small particles orbiting around a planet in flat disc shape. All of the Jovian planets in our solar system have <span class="hlt">rings</span>. But the most notable one is the Saturn's <span class="hlt">ring</span> which is the brightest one. In March 2008 a report suggested that the Saturn's moon Rhea may have its own tenuous <span class="hlt">ring</span> system. The <span class="hlt">ring</span> swirling around Saturn consists of chunks of ice and dust. Most <span class="hlt">rings</span> were thought to be unstable and to dissipate over course of tens or hundreds of millions of years but it now appears that Saturn's <span class="hlt">rings</span> might be older than that. The dust particles in the <span class="hlt">ring</span> collide with each other and are subjected to forces other than gravity of its own planet. Such collisions and extra forces tend to spread out the <span class="hlt">rings</span>. Pluto is not known to have any <span class="hlt">ring</span> system but some Astronomers believe that New Horizons probe might find a <span class="hlt">ring</span> system when it visits in 2015.It is also predicted that Phobos, a moon of Mars will break up and form into a planetary <span class="hlt">ring</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA20496.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA20496.html"><span>Surge in the <span class="hlt">Ring</span></span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2016-08-29</p> <p>An ethereal, glowing spot appears on Saturn's B <span class="hlt">ring</span> in this view from NASA's Cassini spacecraft. There is nothing particular about that place in the <span class="hlt">rings</span> that produces the glowing effect -- instead, it is an example of an "opposition surge" making that area on the <span class="hlt">rings</span> appear extra bright. An opposition surge occurs when the Sun is directly behind the observer looking toward the <span class="hlt">rings</span>. The particular geometry of this observation makes the point in the <span class="hlt">rings</span> appear much, much brighter than would otherwise be expected. This view looks toward the sunlit side of the <span class="hlt">rings</span> from about 28 degrees above the <span class="hlt">ring</span> plane. The image was taken in visible light with the Cassini wide-angle camera on June 26, 2016. The view was acquired at a distance of approximately 940,000 miles (1.5 million kilometers) from the <span class="hlt">rings</span> and at a Sun-<span class="hlt">ring</span>-spacecraft, or phase, angle of 0 degrees. Image scale on the <span class="hlt">rings</span> at center is 56 miles (90 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA20496</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010IEITF..91...83F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010IEITF..91...83F"><span>Traceable <span class="hlt">Ring</span> Signature</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fujisaki, Eiichiro; Suzuki, Koutarou</p> <p></p> <p>The <span class="hlt">ring</span> signature allows a signer to leak secrets anonymously, without the risk of identity escrow. At the same time, the <span class="hlt">ring</span> signature provides great flexibility: No group manager, no special setup, and the dynamics of group choice. The <span class="hlt">ring</span> signature is, however, vulnerable to malicious or irresponsible signers in some applications, because of its anonymity. In this paper, we propose a traceable <span class="hlt">ring</span> signature scheme. A traceable <span class="hlt">ring</span> scheme is a <span class="hlt">ring</span> signature except that it can restrict “excessive” anonymity. The traceable <span class="hlt">ring</span> signature has a tag that consists of a list of <span class="hlt">ring</span> members and an issue that refers to, for instance, a social affair or an election. A <span class="hlt">ring</span> member can make any signed but anonymous opinion regarding the issue, but only once (per tag). If the member submits another signed opinion, possibly pretending to be another person who supports the first opinion, the identity of the member is immediately revealed. If the member submits the same opinion, for instance, voting “yes” regarding the same issue twice, everyone can see that these two are linked. The traceable <span class="hlt">ring</span> signature can suit to many applications, such as an anonymous voting on a BBS. We formalize the security definitions for this primitive and show an efficient and simple construction in the random oracle model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011GeoRL..3824705D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011GeoRL..3824705D"><span>Three centuries of Myanmar monsoon climate variability inferred from teak tree <span class="hlt">rings</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>D'Arrigo, Rosanne; Palmer, Jonathan; Ummenhofer, Caroline C.; Kyaw, Nyi Nyi; Krusic, Paul</p> <p>2011-12-01</p> <p>Asian monsoon extremes critically impact much of the globe’s population. Key gaps in our understanding of monsoon climate remain due to sparse coverage of paleoclimatic information, despite intensified recent efforts. Here we describe a <span class="hlt">ring</span> <span class="hlt">width</span> chronology of teak, one of the first high-resolution proxy records for the nation of Myanmar. Based on 29 samples from 20 living trees and spanning from 1613-2009, this record, from the Maingtha forest reserve north of Mandalay, helps fill a substantial gap in spatial coverage of paleoclimatic records for monsoon Asia. Teak <span class="hlt">growth</span> is positively correlated with rainfall and Palmer Drought Severity Index variability over Myanmar, during and prior to the May-September monsoon season (e.g., r = 0.38 with Yangon rainfall, 0.001, n 68). Importantly, this record also correlates significantly with larger-scale climate indices, including core Indian rainfall (23°N, 76°E a particularly sensitive index of the monsoon), and the El Niño-Southern Oscillation (ENSO). The teak <span class="hlt">ring</span> <span class="hlt">width</span> value following the so-called 1997-98 El Niño of the Century suggests that this was one of the most severe droughts in the past ˜300 years in Myanmar. Evidence for past dry conditions inferred for Myanmar is consistent with tree-<span class="hlt">ring</span> records of decadal megadroughts developed for Thailand and Vietnam. These results confirm the climate signature related to monsoon rainfall in the Myanmar teak record and the considerable potential for future development of climate-sensitive chronologies from Myanmar and the broader region of monsoon Asia.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.B42A..08H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.B42A..08H"><span>Multi-decadal carbon and water relations of African tropical humid forests: a tree-<span class="hlt">ring</span> stable isotope analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hufkens, K.; Beeckman, H.; de Haulleville, T.; Kearsley, E.; Toirambe, B.; Stoffelen, P.; Boeckx, P. F.</p> <p>2012-12-01</p> <p>Little is known about the temporal dynamics of the carbon sequestering capacity and dynamics of African tropical humid forest ecosystems in response to various environmental drivers. This lack of knowledge is mainly due to the absence of ecosystem scale flux measurements of gas exchange. However, tree <span class="hlt">growth</span> often displays itself as alternating pattern of visible <span class="hlt">rings</span> due to the varying <span class="hlt">growth</span> speed of the vascular cambium. Consequently, analysis of tree <span class="hlt">growth</span> through tree-<span class="hlt">ring</span> analysis provides us with insights into past responses of the carbon sequestering capacity of key species to abrupt ecosystem disturbances and, while slower, a changing climate. Not only does the <span class="hlt">width</span> and density of <span class="hlt">growth</span> <span class="hlt">rings</span> reflect annual <span class="hlt">growth</span> but their isotopic composition of 13C and 18O isotopes also reveal the environmental conditions in which the trees were growing. In particular, stable isotope ratios in tree-<span class="hlt">rings</span> of 13C are influenced by fractionation through carboxylation and changes in stomatal conductance. Similarly, fractionation of 18O from soil water occurs at the leaf level through evapo-transipiration. As a consequence, δ18O values in tree cores will reflect both the signal of the source water as well as that of for example summer humidity. Therefore, using both 13C and 18O stable isotopes might not only be valuable proxies of past climatic conditions but also serve as an important tool in understanding carbon and water relations within a forest ecosystems. To this end we correlate long term climate records (1961 - present) with tree <span class="hlt">ring</span> measurement of incremental <span class="hlt">growth</span> and high resolution analysis of tree-core stable isotope (13C / 18O) composition at two functionally similar, but geographically dissimilar, tropical humid forests in DR Congo. A first site, the Luki man and the biosphere (MAB) reserve, is located in the western part of DR Congo influenced by a tropical wet and dry climate. A second site, the Yangambi MAB reserve is located in the north</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.8950H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.8950H"><span>Multi-decadal carbon and water relations of African tropical humid forests: a tree-<span class="hlt">ring</span> stable isotope analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hufkens, Koen; Helle, Gerd; Beeckman, Hans; de Haulleville, Thales; Kearsley, Elizabeth; Boeckx, Pascal</p> <p>2013-04-01</p> <p>Little is known about the temporal dynamics of the carbon sequestering capacity and dynamics of African tropical humid forest ecosystems in response to various environmental drivers. This lack of knowledge is mainly due to the absence of ecosystem scale flux measurements of gas exchange. However, tree <span class="hlt">growth</span> often displays itself as alternating pattern of visible <span class="hlt">rings</span> due to the seasonally varying <span class="hlt">growth</span> speed of the vascular cambium. Consequently, analysis of tree <span class="hlt">growth</span> through tree-<span class="hlt">ring</span> analysis provides us with insights into past responses of the carbon sequestering capacity of key species to abrupt ecosystem disturbances and, while slower, a changing climate. Not only does the <span class="hlt">width</span> and density of <span class="hlt">growth</span> <span class="hlt">rings</span> reflect annual <span class="hlt">growth</span> but their isotopic composition of 13C/12C and 18O/16O isotopes also reveal the environmental conditions in which the trees were growing. In particular, stable isotope ratios in tree-<span class="hlt">rings</span> of carbon are influenced by fractionation through carboxylation during photosynthesis and changes in leaf stomatal conductance. Similarly, fractionation of oxygen isotopes of soil water occurs at the leaf level through evapo-transipiration. As a consequence, 18O/16O (δ18O) values in wood cores will reflect both the signal of the source water as well as that of for example summer humidity. Therefore, both C and O stable isotopes might not only be valuable as proxy data for past climatic conditions but they also serve as an important tool in understanding carbon and water relations within a tropical forest ecosystems. To this end we correlate long term climate records (1961 - present) with tree <span class="hlt">ring</span> measurement of incremental <span class="hlt">growth</span> and high resolution analysis of tree-core stable isotope composition(δ13C , δ18O) at a tropical humid forests in the DR Congo. The Yangambi Man And Biosphere (MAB) reserve is located in the north-eastern part of DR Congo, with a distinct tropical rainforest climate. In addition to the tree-core data records and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/165371','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/165371"><span>Finite banana <span class="hlt">width</span> effect on magnetoacoustic cyclotron instability</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chen, Y.P.; Tsai, S.T.</p> <p>1995-08-01</p> <p>The finite banana <span class="hlt">width</span> (FBW) effect on the coupling between magnetoacoustic waves and the near harmonic gyro-oscillations of the energetic ions/{alpha} particles in tokamaks are studied. The gyrokinetic equation with FBW effect is rederived for the energetic trapped ions. The dispersion relation and <span class="hlt">growth</span> rate of the magnetoacoustic cyclotron instability (MACI) are obtained. It is found that the coherence interaction between the energetic ion trajectory and mode field has a significant effect when the Larmor radius of energetic ions is larger than the wavelength of MACI. Near the low field side the FBW effect destabilizes the mode, while away from it the FBW gives a stabilizing effect. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1993PhyB..184...17K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1993PhyB..184...17K"><span>Device-<span class="hlt">width</span> dependence of plateau <span class="hlt">width</span> in quantum Hall states</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kawaji, S.; Hirakawa, K.; Nagata, M.</p> <p>1993-02-01</p> <p>Hall bar type devices having a total length of 2900 μm, a source and drain electrode <span class="hlt">width</span> of 400 μm and different <span class="hlt">widths</span> w ranging from 10 to 120 μm in its central 600 μm long part are fabricated from a GaAs/AlGaAs wafer with electron mobility of 21 m 2V -1s -1. The current at which the quantum Hall plateau for i=2 at B=9.7T at T=1.2K disappears is proportional to w. The average critical current density is Jcr=(1.6±0.2) A m -1</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18592923','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18592923"><span>What forces act on a flat rigid mitral annuloplasty <span class="hlt">ring</span>?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jensen, Morten Ø; Jensen, Henrik; Nielsen, Sten L; Smerup, Morten; Johansen, Peter; Yoganathan, Ajit P; Nygaard, Hans; Hasenkam, J Michael</p> <p>2008-05-01</p> <p>Increasing mitral valve repair durability requires successful restoration and support with annuloplasty <span class="hlt">rings</span>. The stress distribution in these devices indirectly determines the success of the repair. It is hypothesized that changes in annular geometry throughout the cardiac cycle result in adverse strain distribution in stiff, flat annuloplasty <span class="hlt">rings</span>, and hence non-physiological loading of the myocardium. The study aim was to identify the three-dimensional (3-D) force distribution in mitral annuloplasty <span class="hlt">rings</span>. Eight animals were included in an acute porcine study. The mitral annulus 3-D dynamic geometry was assessed with sonomicrometry prior to <span class="hlt">ring</span> insertion. Strain gauges mounted on dedicated D-shaped rigid flat annuloplasty <span class="hlt">rings</span> enabled dynamic force measurements to be made perpendicular to the annulus plane. The average systolic annular height to commissural <span class="hlt">width</span> ratio before <span class="hlt">ring</span> implantation was 13.7 +/- 1.4%. Following <span class="hlt">ring</span> implantation, the annulus was fixed in the diastolic flat configuration (p <0.01). Force accumulation was seen from the anterior (0.7 +/- 0.4 N) and commissural (1.4 +/- 1.0 N) annular segments; both forces were acting in opposite directions and were statistically significantly larger than zero (p <0.01; n = 8). These data demonstrate highest strains at the anterior and commissural areas of flat mitral annuloplasty <span class="hlt">rings</span>, and support the hypothesis that the mitral valve annulus and its attached valvular and subvalvular structures apply systolic torque onto the flat annuloplasty <span class="hlt">ring</span> in an attempt to conform it into the saddle-shaped configuration.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3654428','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3654428"><span>Suppressor of K+ transport <span class="hlt">growth</span> defect 1 (SKD1) interacts with <span class="hlt">RING</span>-type ubiquitin ligase and sucrose non-fermenting 1-related protein kinase (SnRK1) in the halophyte ice plant</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Chiang, Chih-Pin; Li, Chang-Hua; Jou, Yingtzy; Chen, Yu-Chan; Lin, Ya-Chung; Yang, Fang-Yu; Huang, Nu-Chuan; Yen, Hungchen Emilie</p> <p>2013-01-01</p> <p>SKD1 (suppressor of K+ transport <span class="hlt">growth</span> defect 1) is an AAA-type ATPase that functions as a molecular motor. It was previously shown that SKD1 accumulates in epidermal bladder cells of the halophyte Mesembryanthemum crystallinum. SKD1 knock-down Arabidopsis mutants showed an imbalanced Na+/K+ ratio under salt stress. Two enzymes involved in protein post-translational modifications that physically interacted with McSKD1 were identified. McCPN1 (copine 1), a <span class="hlt">RING</span>-type ubiquitin ligase, has an N-terminal myristoylation site that links to the plasma membrane, a central copine domain that interacts with McSKD1, and a C-terminal <span class="hlt">RING</span> domain that catalyses protein ubiquitination. In vitro ubiquitination assay demonstrated that McCPN1 was capable of mediating ubiquitination of McSKD1. McSnRK1 (sucrose non-fermenting 1-related protein kinase) is a Ser/Thr protein kinase that contains an N-terminal STKc catalytic domain to phosphorylate McSKD1, and C-terminal UBA and KA1 domains to interact with McSKD1. The transcript and protein levels of McSnRK1 increased as NaCl concentrations increased. The formation of an SKD1–SnRK1–CPN1 ternary complex was demonstrated by yeast three-hybrid and bimolecular fluorescence complementation. It was found that McSKD1 preferentially interacts with McSnRK1 in the cytosol, and salt induced the re-distribution of McSKD1 and McSnRK1 towards the plasma membrane via the microtubule cytoskeleton and subsequently interacted with <span class="hlt">RING</span>-type E3 McCPN1. The potential effects of ubiquitination and phosphorylation on McSKD1, such as changes in the ATPase activity and cellular localization, and how they relate to the functions of SKD1 in the maintenance of Na+/K+ homeostasis under salt stress, are discussed. PMID:23580756</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19830059291&hterms=Bakshi&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DBakshi','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19830059291&hterms=Bakshi&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DBakshi"><span>Finite-<span class="hlt">width</span> currents, magnetic shear, and the current-driven ion-cyclotron instability</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bakshi, P.; Ganguli, G.; Palmadesso, P.</p> <p>1983-01-01</p> <p>Our earlier results that non-local effects due to even a small magnetic shear produce a significant reduction of the <span class="hlt">growth</span> rate of the ion cyclotron instability driven by a uniform current are now generalized to finite <span class="hlt">width</span> currents. Externally prescribed as well as self-consistent shears are considered. If the current <span class="hlt">width</span> Lc exceeds the shear length Ls, the previous results are recovered. Shear becomes less effective with reduction of Lc, and for typical parameters, the <span class="hlt">growth</span> rate attains its (shearless) local value for Lc/Ls approximately less than 10 to the minus 2. Non-local effects of the finite current <span class="hlt">width</span> itself come into play if Lc is further reduced to a few ion Larmor radii and can quench the instability. Previously announced in STAR as N83-28996</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19830059291&hterms=Chestnut&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DChestnut','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19830059291&hterms=Chestnut&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DChestnut"><span>Finite-<span class="hlt">width</span> currents, magnetic shear, and the current-driven ion-cyclotron instability</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bakshi, P.; Ganguli, G.; Palmadesso, P.</p> <p>1983-01-01</p> <p>Our earlier results that non-local effects due to even a small magnetic shear produce a significant reduction of the <span class="hlt">growth</span> rate of the ion cyclotron instability driven by a uniform current are now generalized to finite <span class="hlt">width</span> currents. Externally prescribed as well as self-consistent shears are considered. If the current <span class="hlt">width</span> Lc exceeds the shear length Ls, the previous results are recovered. Shear becomes less effective with reduction of Lc, and for typical parameters, the <span class="hlt">growth</span> rate attains its (shearless) local value for Lc/Ls approximately less than 10 to the minus 2. Non-local effects of the finite current <span class="hlt">width</span> itself come into play if Lc is further reduced to a few ion Larmor radii and can quench the instability. Previously announced in STAR as N83-28996</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19590897','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19590897"><span>Do centennial tree-<span class="hlt">ring</span> and stable isotope trends of Larix gmelinii (Rupr.) Rupr. indicate increasing water shortage in the Siberian north?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sidorova, Olga Vladimirovna; Siegwolf, Rolf T W; Saurer, Matthias; Shashkin, Alexander V; Knorre, Anastasia A; Prokushkin, Anatoliy S; Vaganov, Eugene A; Kirdyanov, Alexander V</p> <p>2009-10-01</p> <p>Tree-<span class="hlt">ring</span> <span class="hlt">width</span> of Larix gmelinii (Rupr.) Rupr., ratios of stable isotopes of C (delta(13)C) and O (delta(18)O) of whole wood and cellulose chronologies were obtained for the northern part of central Siberia (Tura, Russia) for the period 1864-2006. A strong decrease in the isotope ratios of O and C (after atmospheric delta(13)C corrections) and tree-<span class="hlt">ring</span> <span class="hlt">width</span> was observed for the period 1967-2005, while weather station data show a decrease in July precipitation, along with increasing July air temperature and vapor pressure deficit (VPD). Temperature at the end of May and the whole month of June mainly determines tree radial <span class="hlt">growth</span> and marks the beginning of the vegetation period in this region. A positive correlation between tree-<span class="hlt">ring</span> <span class="hlt">width</span> and July precipitation was found for the calibration period 1929-2005. Positive significant correlations between C isotope chronologies and temperatures of June and July were found for whole wood and cellulose and negative relationships with July precipitation. These relationships are strengthened when the likely physiological response of trees to increased CO(2) is taken into account (by applying a recently developed delta(13)C correction). For the O isotope ratios, positive relationships with annual temperature, VPD of July and a negative correlation with annual precipitation were observed. The delta(18)O in tree <span class="hlt">rings</span> may reflect annual rather than summer temperatures, due to the late melting of the winter snow and its contribution to the tree water supply in summer. We observed a clear change in the isotope and climate trends after the 1960s, resulting in a drastic change in the relationship between C and O isotope ratios from a negative to a positive correlation. According to isotope fractionation models, this indicates reduced stomatal conductance at a relatively constant photosynthetic rate, as a response of trees to water deficit for the last half century in this permafrost region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008APS..DFD.PD005D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008APS..DFD.PD005D"><span>Slowing of Vortex <span class="hlt">Rings</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Donnelly, Russell; Bolster, Diogo; Hershberger, Robert</p> <p>2008-11-01</p> <p>We have investigated the slowing of vortex <span class="hlt">rings</span> in water which are created with very thin cores. We find that these <span class="hlt">rings</span> propagate with no measurable change in diameter or core size. The drag appears to be the result of viscous forces on the core. A simple model for this drag describes experimental data in terms of a drag coefficient, which depends only on Reynolds number. Barenghi's group at Newcastle found that the translational velocity of a <span class="hlt">ring</span> in an inviscid fluid perturbed by Kelvin waves decreases with increasing amplitude of Kelvin waves. This suggests that the velocity of vortex <span class="hlt">rings</span> in a viscous fluid may well depend on the amplitude of Kelvin waves at the time of formation. <span class="hlt">Rings</span> with substantial amplitude of Kelvin waves will be expected to move more slowly than <span class="hlt">rings</span> with little or no Kelvin wave amplitude. We present experimental data confirming this suggestion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA20506.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA20506.html"><span><span class="hlt">Ring</span> Details on Display</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2016-11-07</p> <p>This view from NASA's Cassini spacecraft showcases some of the amazingly detailed structure of Saturn's <span class="hlt">rings</span>. The <span class="hlt">rings</span> are made up of many smaller ringlets that blur together when seen from a distance. But when imaged up close, the <span class="hlt">rings</span>' structures display quite a bit of variation. <span class="hlt">Ring</span> scientists are debating the nature of these features -- whether they have always appeared this way or if their appearance has evolved over time. This view looks toward the sunlit side of the <span class="hlt">rings</span> from about 4 degrees above the <span class="hlt">ring</span> plane. The image was taken in visible light with the Cassini spacecraft wide-angle camera on Sept. 24, 2016. The view was acquired at a distance of approximately 283,000 miles (456,000 kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 32 degrees. Image scale is 17 miles (27 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA20506</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/965910','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/965910"><span>Direct measurement of the W boson <span class="hlt">width</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Abazov, V.M.; Abbott, B.; Abolins, M.; Acharya, B.S.; Adams, M.; Adams, T.; Aguilo, E.; Ahsan, M.; Alexeev, G.D.; Alkhazov, G.; Alton, A.; /Michigan U. /Northeastern U.</p> <p>2009-09-01</p> <p>We present a direct measurement of the <span class="hlt">width</span> of the W boson using the shape of the transverse mass distribution of W {yields} e{nu} candidates selected in 1 fb{sup -1} of data collected with the D0 detector at the Fermilab Tevatron collider in p{bar p} collisions at {radical}s = 1.96 TeV. We use the same methods and data sample that were used for our recently published W boson mass measurement, except for the modeling of the recoil, which is done with a new method based on a recoil library. Our result, 2.028 {+-} 0.072 GeV, is in agreement with the predictions of the standard model and is the most precise direct measurement result from a single experiment to date.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20366142','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20366142"><span>Direct measurement of the W boson <span class="hlt">width</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Abazov, V M; Abbott, B; Abolins, M; Acharya, B S; Adams, M; Adams, T; Aguilo, E; Ahsan, M; Alexeev, G D; Alkhazov, G; Alton, A; Alverson, G; Alves, G A; Ancu, L S; Andeen, T; Anzelc, M S; Aoki, M; Arnoud, Y; Arov, M; Arthaud, M; Askew, A; Asman, B; Atramentov, O; Avila, C; BackusMayes, J; Badaud, F; Bagby, L; Baldin, B; Bandurin, D V; Banerjee, S; Barberis, E; Barfuss, A-F; Bargassa, P; Baringer, P; Barreto, J; Bartlett, J F; Bassler, U; Bauer, D; Beale, S; Bean, A; Begalli, M; Begel, M; Belanger-Champagne, C; Bellantoni, L; Benitez, J A; Beri, S B; Bernardi, G; Bernhard, R; Bertram, I; Besançon, M; Beuselinck, R; Bezzubov, V A; Bhat, P C; Bhatnagar, V; Blazey, G; Blessing, S; Bloom, K; Boehnlein, A; Boline, D; Bolton, T A; Boos, E E; Borissov, G; Bose, T; Brandt, A; Brock, R; Brooijmans, G; Bross, A; Brown, D; Bu, X B; Buchholz, D; Buehler, M; Buescher, V; Bunichev, V; Burdin, S; Burnett, T H; Buszello, C P; Calfayan, P; Calpas, B; Calvet, S; Cammin, J; Carrasco-Lizarraga, M A; Carrera, E; Carvalho, W; Casey, B C K; Castilla-Valdez, H; Chakrabarti, S; Chakraborty, D; Chan, K M; Chandra, A; Cheu, E; Cho, D K; Cho, S W; Choi, S; Choudhary, B; Christoudias, T; Cihangir, S; Claes, D; Clutter, J; Cooke, M; Cooper, W E; Corcoran, M; Couderc, F; Cousinou, M-C; Cutts, D; Cwiok, M; Das, A; Davies, G; De, K; de Jong, S J; De La Cruz-Burelo, E; DeVaughan, K; Déliot, F; Demarteau, M; Demina, R; Denisov, D; Denisov, S P; Desai, S; Diehl, H T; Diesburg, M; Dominguez, A; Dorland, T; Dubey, A; Dudko, L V; Duflot, L; Duggan, D; Duperrin, A; Dutt, S; Dyshkant, A; Eads, M; Edmunds, D; Ellison, J; Elvira, V D; Enari, Y; Eno, S; Escalier, M; Evans, H; Evdokimov, A; Evdokimov, V N; Facini, G; Ferapontov, A V; Ferbel, T; Fiedler, F; Filthaut, F; Fisher, W; Fisk, H E; Fortner, M; Fox, H; Fuess, S; Gadfort, T; Galea, C F; Garcia-Bellido, A; Gavrilov, V; Gay, P; Geist, W; Geng, W; Gerber, C E; Gershtein, Y; Gillberg, D; Ginther, G; Golovanov, G; Gómez, B; Goussiou, A; Grannis, P D; Greder, S; Greenlee, H; Greenwood, Z D; Gregores, E M; Grenier, G; Gris, Ph; Grivaz, J-F; Grohsjean, A; Grünendahl, S; Grünewald, M W; Guo, F; Guo, J; Gutierrez, G; Gutierrez, P; Haas, A; Haefner, P; Hagopian, S; Haley, J; Hall, I; Hall, R E; Han, L; Harder, K; Harel, A; Hauptman, J M; Hays, J; Hebbeker, T; Hedin, D; Hegeman, J G; Heinson, A P; Heintz, U; Hensel, C; Heredia-De La Cruz, I; Herner, K; Hesketh, G; Hildreth, M D; Hirosky, R; Hoang, T; Hobbs, J D; Hoeneisen, B; Hohlfeld, M; Hossain, S; Houben, P; Hu, Y; Hubacek, Z; Huske, N; Hynek, V; Iashvili, I; Illingworth, R; Ito, A S; Jabeen, S; Jaffré, M; Jain, S; Jakobs, K; Jamin, D; Jesik, R; Johns, K; Johnson, C; Johnson, M; Johnston, D; Jonckheere, A; Jonsson, P; Juste, A; Kajfasz, E; Karmanov, D; Kasper, P A; Katsanos, I; Kaushik, V; Kehoe, R; Kermiche, S; Khalatyan, N; Khanov, A; Kharchilava, A; Kharzheev, Y N; Khatidze, D; Kirby, M H; Kirsch, M; Klima, B; Kohli, J M; Konrath, J-P; Kozelov, A V; Kraus, J; Kuhl, T; Kumar, A; Kupco, A; Kurca, T; Kuzmin, V A; Kvita, J; Lacroix, F; Lam, D; Lammers, S; Landsberg, G; Lebrun, P; Lee, H S; Lee, W M; Leflat, A; Lellouch, J; Li, L; Li, Q Z; Lietti, S M; Lim, J K; Lincoln, D; Linnemann, J; Lipaev, V V; Lipton, R; Liu, Y; Liu, Z; Lobodenko, A; Lokajicek, M; Love, P; Lubatti, H J; Luna-Garcia, R; Lyon, A L; Maciel, A K A; Mackin, D; Mättig, P; Magaña-Villalba, R; Mal, P K; Malik, S; Malyshev, V L; Maravin, Y; Martin, B; McCarthy, R; McGivern, C L; Meijer, M M; Melnitchouk, A; Mendoza, L; Menezes, D; Mercadante, P G; Merkin, M; Meyer, A; Meyer, J; Mondal, N K; Montgomery, H E; Moore, R W; Moulik, T; Muanza, G S; Mulhearn, M; Mundal, O; Mundim, L; Nagy, E; Naimuddin, M; Narain, M; Neal, H A; Negret, J P; Neustroev, P; Nilsen, H; Nogima, H; Novaes, S F; Nunnemann, T; Obrant, G; Ochando, C; Onoprienko, D; Orduna, J; Oshima, N; Osman, N; Osta, J; Otec, R; Otero y Garzón, G J; Owen, M; Padilla, M; Padley, P; Pangilinan, M; Parashar, N; Park, S-J; Park, S K; Parsons, J; Partridge, R; Parua, N; Patwa, A; Penning, B; Perfilov, M; Peters, K; Peters, Y; Pétroff, P; Piegaia, R; Piper, J; Pleier, M-A; Podesta-Lerma, P L M; Podstavkov, V M; Pogorelov, Y; Pol, M-E; Polozov, P; Popov, A V; Prewitt, M; Protopopescu, S; Qian, J; Quadt, A; Quinn, B; Rakitine, A; Rangel, M S; Ranjan, K; Ratoff, P N; Renkel, P; Rich, P; Rijssenbeek, M; Ripp-Baudot, I; Rizatdinova, F; Robinson, S; Rominsky, M; Royon, C; Rubinov, P; Ruchti, R; Safronov, G; Sajot, G; Sánchez-Hernández, A; Sanders, M P; Sanghi, B; Savage, G; Sawyer, L; Scanlon, T; Schaile, D; Schamberger, R D; Scheglov, Y; Schellman, H; Schliephake, T; Schlobohm, S; Schwanenberger, C; Schwienhorst, R; Sekaric, J; Severini, H; Shabalina, E; Shamim, M; Shary, V; Shchukin, A A; Shivpuri, R K; Siccardi, V; Simak, V; Sirotenko, V; Skubic, P; Slattery, P; Smirnov, D; Snow, G R; Snow, J; Snyder, S; Söldner-Rembold, S; Sonnenschein, L; Sopczak, A; Sosebee, M; Soustruznik, K; Spurlock, B; Stark, J; Stolin, V; Stoyanova, D A; Strandberg, J; Strang, M A; Strauss, E; Strauss, M; Ströhmer, R; Strom, D; Stutte, L; Sumowidagdo, S; Svoisky, P; Takahashi, M; Tanasijczuk, A; Taylor, W; Tiller, B; Titov, M; Tokmenin, V V; Torchiani, I; Tsybychev, D; Tuchming, B; Tully, C; Tuts, P M; Unalan, R; Uvarov, L; Uvarov, S; Uzunyan, S; van den Berg, P J; Van Kooten, R; van Leeuwen, W M; Varelas, N; Varnes, E W; Vasilyev, I A; Verdier, P; Vertogradov, L S; Verzocchi, M; Vesterinen, M; Vilanova, D; Vint, P; Vokac, P; Wagner, R; Wahl, H D; Wang, M H L S; Warchol, J; Watts, G; Wayne, M; Weber, G; Weber, M; Wenger, A; Wetstein, M; White, A; Wicke, D; Williams, M R J; Wilson, G W; Wimpenny, S J; Wobisch, M; Wood, D R; Wyatt, T R; Xie, Y; Xu, C; Yacoob, S; Yamada, R; Yang, W-C; Yasuda, T; Yatsunenko, Y A; Ye, Z; Yin, H; Yip, K; Yoo, H D; Youn, S W; Yu, J; Zeitnitz, C; Zelitch, S; Zhao, T; Zhou, B; Zhu, J; Zielinski, M; Zieminska, D; Zivkovic, L; Zutshi, V; Zverev, E G</p> <p>2009-12-04</p> <p>We present a direct measurement of the <span class="hlt">width</span> of the W boson using the shape of the transverse mass distribution of W --> enu candidate events. Data from approximately 1 fb(-1) of integrated luminosity recorded at square root of s = 1.96 TeV by the D0 detector at the Fermilab Tevatron pp collider are analyzed. We use the same methods and data sample that were used for our recently published W boson mass measurement, except for the modeling of the recoil, which is done with a new method based on a recoil library. Our result, 2.028 +/- 0.072 GeV, is in agreement with the predictions of the standard model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5107391','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5107391"><span>Red cell distribution <span class="hlt">width</span> and cancer</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Danese, Elisa</p> <p>2016-01-01</p> <p>Red cell distribution <span class="hlt">width</span> (RDW) is an index which primarily reflects impaired erythropoiesis and abnormal red blood cell survival. In last years the interest in this marker has considerably grown and now a lot of data are available indicating that this simple and inexpensive parameter is a strong and independent risk factor for death in the general population. Moreover, several investigations have been performed to investigate the role of RDW in cardiovascular and thrombotic disorders. Contrarily, there are relatively few reports focusing on RDW in the area of oncology and to date none review have been performed in this specific field. As such, the aim of this narrative review is to summarize some interesting results obtained in studies performed in patients affected by solid and hematological tumors. Even if larger studies are needed before these preliminary findings can be generalized, it seems plausible to affirm that RDW can be useful by adding prognostic information in patients with oncologic disease. PMID:27867951</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005DPS....37.6201C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005DPS....37.6201C"><span>Saturn's <span class="hlt">rings</span> - an overview</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cuzzi, J. N.</p> <p>2005-08-01</p> <p>Saturn's <span class="hlt">rings</span> embody in their diversity the entire spectrum of <span class="hlt">ring</span> properties seen across the outer solar system, and remain unique in fundamental ways. The Voyager flybys revealed their complexity in 1980-1981, while groundbased and HST observations have provided important new insights since that time. Since July 2004, when it skimmed only tens of thousands of km over the unlit face of the <span class="hlt">rings</span> - collecting unique remote and in-situ observations as it entered orbit - Cassini has been fulfilling the long-held dream of understanding Saturn's <span class="hlt">rings</span> in depth. As of this meeting, if all continues as planned, seven orbits designed specifically with <span class="hlt">ring</span> observations in mind will have been completed - each providing even better geometric opportunities than an entire Voyager flyby (to a spacecraft with far more powerful instruments than Voyager). Even these represent only a fraction of what the complete mission will tell us about the <span class="hlt">rings</span>. This talk will review the key properties of the <span class="hlt">rings</span>, highlight the themes and new insights emerging from recent studies, and serve as a context for new results presented at the meeting. The key properties include the relationship of the <span class="hlt">rings</span> to their close-in and embedded moons; the composition of the <span class="hlt">rings</span> and its spatial variation; and the complex radial and vertical structure of the <span class="hlt">rings</span>, as related to local particle sizes and mass density. The main themes are that several evolutionary processes cause all these to vary - we think substantially - with time, and that the <span class="hlt">rings</span> may be much younger than Saturn. To achieve our goal of understanding the origin of the <span class="hlt">rings</span>, we must start from an in-depth characterization of their current state, and peer back through their extensive evolution. Cassini observations, and their theoretical analysis, will ultimately make this possible.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6508834','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6508834"><span>Radioactive gold <span class="hlt">ring</span> dermatitis</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Miller, R.A.; Aldrich, J.E. )</p> <p>1990-08-01</p> <p>A superficial squamous cell carcinoma developed in a woman who wore a radioactive gold <span class="hlt">ring</span> for more than 30 years. Only part of the <span class="hlt">ring</span> was radioactive. Radiation dose measurements indicated that the dose to basal skin layer was 2.4 Gy (240 rad) per week. If it is assumed that the woman continually wore her wedding <span class="hlt">ring</span> for 37 years since purchase, she would have received a maximum dose of approximately 4600 Gy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2732043','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2732043"><span>Human 2D (index) and 4D (<span class="hlt">ring</span>) finger lengths and ratios: cross-sectional data on linear <span class="hlt">growth</span> patterns, sexual dimorphism and lateral asymmetry from 4 to 60 years of age</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Gillam, L; McDonald, R; Ebling, F J P; Mayhew, T M</p> <p>2008-01-01</p> <p>Human 2D:4D ratios (measures of the relative lengths of index and <span class="hlt">ring</span> fingers) attract considerable research interest because they exhibit sexual dimorphism and are associated with various morphological, physiological and behavioural traits as well as sporting abilities and medical conditions. In an attempt to identify potential confounding factors in such studies, we have examined how relative and absolute digit lengths vary with gender and tested whether they are influenced by age, right–left asymmetry and hand preference. Participants between 4 and 60years of age were recruited from local educational sites. Hand photocopies and calliper measurement were used to obtain digit lengths. We employed linear regression analysis to examine the <span class="hlt">growth</span> trajectories of individual digits, analyses of variance to isolate main and interaction effects of age, gender and hand preference, and paired t-tests to identify lateral asymmetries. Both digits exhibited biphasic <span class="hlt">growth</span> with an early <span class="hlt">growth</span> phase followed by a stable length phase. Digits in females attained their maximum length about 2.2years (dextral subjects) or 5.1years (sinistral subjects) earlier than those in males. Sexual dimorphism in 2D:4D ratios was apparent by 4years of age and age changes in ratios depended on gender, side and hand preference. Relative and absolute lengths displayed age, gender, hand-preference and age×gender interaction effects. Lengths tended to be greater in females in younger subjects and greater in males in older subjects. Ratios tended to be greater in sinistral subjects. In dextral subjects, significant lateral asymmetries in 2D lengths were seen at all ages but asymmetries in males and 4D lengths seemed to be age-dependent. We conclude that age, lateral asymmetry and hand preference are potential confounding factors and that future study designs should take account of these as well as other known confounders such as ethnicity, birth order, menstrual cycle phase and sexual</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA20509.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA20509.html"><span>Tiny Mimas, Huge <span class="hlt">Rings</span></span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2016-11-28</p> <p>Saturn's icy moon Mimas is dwarfed by the planet's enormous <span class="hlt">rings</span>. Because Mimas (near lower left) appears tiny by comparison, it might seem that the <span class="hlt">rings</span> would be far more massive, but this is not the case. Scientists think the <span class="hlt">rings</span> are no more than a few times as massive as Mimas, or perhaps just a fraction of Mimas' mass. Cassini is expected to determine the mass of Saturn's <span class="hlt">rings</span> to within just a few hundredths of Mimas' mass as the mission winds down by tracking radio signals from the spacecraft as it flies close to the <span class="hlt">rings</span>. The <span class="hlt">rings</span>, which are made of small, icy particles spread over a vast area, are extremely thin -- generally no thicker than the height of a house. Thus, despite their giant proportions, the <span class="hlt">rings</span> contain a surprisingly small amount of material. Mimas is 246 miles (396 kilometers) wide. This view looks toward the sunlit side of the <span class="hlt">rings</span> from about 6 degrees above the <span class="hlt">ring</span> plane. The image was taken in red light with the Cassini spacecraft wide-angle camera on July 21, 2016. The view was obtained at a distance of approximately 564,000 miles (907,000 kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 31 degrees. Image scale is 34 miles (54 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA20509</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA18313.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA18313.html"><span>Faint D <span class="hlt">Ring</span></span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2015-04-27</p> <p>Not all of Saturn's <span class="hlt">rings</span> are created equal: here the C and D <span class="hlt">rings</span> appear side-by-side, but the C <span class="hlt">ring</span>, which occupies the bottom half of this image, clearly outshines its neighbor. The D <span class="hlt">ring</span> appears fainter than the C <span class="hlt">ring</span> because it is comprised of less material. However, even <span class="hlt">rings</span> as thin as the D <span class="hlt">ring</span> can pose hazards to spacecraft. Given the high speeds at which Cassini travels, impacts with particles just fractions of a millimeter in size have the potential to damage key spacecraft components and instruments. Nonetheless, near the end of Cassini's mission, navigators plan to thread the spacecraft's orbit through the narrow region between the D <span class="hlt">ring</span> and the top of Saturn's atmosphere. This view looks toward the unilluminated side of the <span class="hlt">rings</span> from about 12 degrees below the ringplane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Feb. 11, 2015. The view was acquired at a distance of approximately 372,000 miles (599,000 kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 133 degrees. Image scale is 2.2 miles (3.6 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/pia18313</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA00658&hterms=Halo&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DHalo','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA00658&hterms=Halo&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DHalo"><span>Jupiter's <span class="hlt">Ring</span> Halo</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1997-01-01</p> <p>A mosaic of four images taken through the clear filter (610 nanometers) of the solid state imaging (CCD) system aboard NASA's Galileo spacecraft on November 8, 1996, at a resolution of approximately 46 kilometers (km) per picture element (pixel) along the <span class="hlt">rings</span>; however, because the spacecraft was only about 0.5 degrees above the <span class="hlt">ring</span> plane, the image is highly foreshortened in the vertical direction. The images were obtained when Galileo was in Jupiter's shadow peering back toward the Sun; the <span class="hlt">ring</span> was approximately 2,300,000 kilometers (km) away. The arc on the far right of the image is produced by sunlight scattered by small particles comprising Jupiter's upper atmospheric haze. The <span class="hlt">ring</span> also efficiently scatters light, indicating that much of its brightness is due to particles that are microns or less in diameter. Such small particles are believed to have human-scale lifetimes, i.e., very brief compared to the solar system's age.<p/>Jupiter's <span class="hlt">ring</span> system is composed of three parts -- a flat main <span class="hlt">ring</span>, a lenticular halo interior to the main <span class="hlt">ring</span>, and the gossamer <span class="hlt">ring</span>, which lies exterior to the main <span class="hlt">ring</span>. The near and far arms of Jupiter's main <span class="hlt">ring</span> extend horizontally across the mosaic, joining together at the <span class="hlt">ring</span>'s ansa, on the far left side of the figure. The near arm of the <span class="hlt">ring</span> appears to be abruptly truncated close to the planet, at the point where it passes into Jupiter's shadow.<p/>A faint mist of particles can be seen above and below the main <span class="hlt">rings</span>; this vertically extended, toroidal 'halo' is unusual in planetary <span class="hlt">rings</span>, and is probably caused by electromagnetic forces which can push small grains out of the <span class="hlt">ring</span> plane. Halo material is present across this entire image, implying that it reaches more than 27,000 km above the <span class="hlt">ring</span> plane. Because of shadowing, the halo is not visible close to Jupiter in the lower right part of the mosaic. In order to accentuate faint features in the image, different brightnesses are shown through color, with the brightest</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA00658&hterms=halo&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dhalo','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA00658&hterms=halo&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dhalo"><span>Jupiter's <span class="hlt">Ring</span> Halo</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1997-01-01</p> <p>A mosaic of four images taken through the clear filter (610 nanometers) of the solid state imaging (CCD) system aboard NASA's Galileo spacecraft on November 8, 1996, at a resolution of approximately 46 kilometers (km) per picture element (pixel) along the <span class="hlt">rings</span>; however, because the spacecraft was only about 0.5 degrees above the <span class="hlt">ring</span> plane, the image is highly foreshortened in the vertical direction. The images were obtained when Galileo was in Jupiter's shadow peering back toward the Sun; the <span class="hlt">ring</span> was approximately 2,300,000 kilometers (km) away. The arc on the far right of the image is produced by sunlight scattered by small particles comprising Jupiter's upper atmospheric haze. The <span class="hlt">ring</span> also efficiently scatters light, indicating that much of its brightness is due to particles that are microns or less in diameter. Such small particles are believed to have human-scale lifetimes, i.e., very brief compared to the solar system's age.<p/>Jupiter's <span class="hlt">ring</span> system is composed of three parts -- a flat main <span class="hlt">ring</span>, a lenticular halo interior to the main <span class="hlt">ring</span>, and the gossamer <span class="hlt">ring</span>, which lies exterior to the main <span class="hlt">ring</span>. The near and far arms of Jupiter's main <span class="hlt">ring</span> extend horizontally across the mosaic, joining together at the <span class="hlt">ring</span>'s ansa, on the far left side of the figure. The near arm of the <span class="hlt">ring</span> appears to be abruptly truncated close to the planet, at the point where it passes into Jupiter's shadow.<p/>A faint mist of particles can be seen above and below the main <span class="hlt">rings</span>; this vertically extended, toroidal 'halo' is unusual in planetary <span class="hlt">rings</span>, and is probably caused by electromagnetic forces which can push small grains out of the <span class="hlt">ring</span> plane. Halo material is present across this entire image, implying that it reaches more than 27,000 km above the <span class="hlt">ring</span> plane. Because of shadowing, the halo is not visible close to Jupiter in the lower right part of the mosaic. In order to accentuate faint features in the image, different brightnesses are shown through color, with the brightest</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1980Sci...209..277F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1980Sci...209..277F"><span>Saturn's E <span class="hlt">ring</span> revisited</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Feibelman, W. A.; Klinglesmith, D. A.</p> <p>1980-07-01</p> <p>Images of the E <span class="hlt">ring</span> of Saturn obtained by the image processing of photographs of the 1966 edge-on presentation of the planet's <span class="hlt">ring</span> plane are presented. Two methods of image enhancement were used: scanning with an image quantizer operated in the derivative mode to enhance contrast and computerized subtraction of a circularly symmetric image of the overexposed Saturn disk. Further photographic and CCD observation confirming the existence of the <span class="hlt">ring</span> extending to twice the diameter of the A <span class="hlt">ring</span>, which was not detected by the Pioneer 11 imaging photopolarimeter, is indicated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA00658.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA00658.html"><span>Jupiter <span class="hlt">Ring</span> Halo</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>1998-03-26</p> <p>A mosaic of four images taken through the clear filter (610 nanometers) of the solid state imaging (CCD) system aboard NASA's Galileo spacecraft on November 8, 1996, at a resolution of approximately 46 kilometers (km) per picture element (pixel) along the <span class="hlt">rings</span>; however, because the spacecraft was only about 0.5 degrees above the <span class="hlt">ring</span> plane, the image is highly foreshortened in the vertical direction. The images were obtained when Galileo was in Jupiter's shadow peering back toward the Sun; the <span class="hlt">ring</span> was approximately 2,300,000 kilometers (km) away. The arc on the far right of the image is produced by sunlight scattered by small particles comprising Jupiter's upper atmospheric haze. The <span class="hlt">ring</span> also efficiently scatters light, indicating that much of its brightness is due to particles that are microns or less in diameter. Such small particles are believed to have human-scale lifetimes, i.e., very brief compared to the solar system's age. Jupiter's <span class="hlt">ring</span> system is composed of three parts -- a flat main <span class="hlt">ring</span>, a lenticular halo interior to the main <span class="hlt">ring</span>, and the gossamer <span class="hlt">ring</span>, which lies exterior to the main <span class="hlt">ring</span>. The near and far arms of Jupiter's main <span class="hlt">ring</span> extend horizontally across the mosaic, joining together at the <span class="hlt">ring</span>'s ansa, on the far left side of the figure. The near arm of the <span class="hlt">ring</span> appears to be abruptly truncated close to the planet, at the point where it passes into Jupiter's shadow. A faint mist of particles can be seen above and below the main <span class="hlt">rings</span>; this vertically extended, toroidal "halo" is unusual in planetary <span class="hlt">rings</span>, and is probably caused by electromagnetic forces which can push small grains out of the <span class="hlt">ring</span> plane. Halo material is present across this entire image, implying that it reaches more than 27,000 km above the <span class="hlt">ring</span> plane. Because of shadowing, the halo is not visible close to Jupiter in the lower right part of the mosaic. In order to accentuate faint features in the image, different brightnesses are shown through color, with the brightest being</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19850018196&hterms=kinematic+viscosity&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dkinematic%2Bviscosity','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19850018196&hterms=kinematic+viscosity&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dkinematic%2Bviscosity"><span>Viscosity in Saturn's <span class="hlt">rings</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lissauer, J. J.; Shu, F. H.; Cuzzi, J. N.</p> <p>1982-01-01</p> <p>The technique of estimating the viscosity in Saturn's <span class="hlt">rings</span> from the damping rate of waves observed to be propagating within the <span class="hlt">rings</span> is discussed. The wavetrains of attempts using spiral density waves as a diagnostic suffer significant complications that compromise the interpretations. A method that considers the damping of spiral bending waves was used to deduce a kinematic viscosity of 260 (+150, -100) sqcm/sec for the middle of the A <span class="hlt">ring</span> where bending waves are excited by the 5:3 vertical resonance with Mimas. This value implies upper limits on the particle velocity dispersion and local <span class="hlt">ring</span> thickness of 0.4 cm/sec and 30 m, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17938105','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17938105"><span>Leaf traits and tree <span class="hlt">rings</span> suggest different water-use and carbon assimilation strategies by two co-occurring Quercus species in a Mediterranean mixed-forest stand in Tuscany, Italy.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tognetti, Roberto; Cherubini, Paolo; Marchi, Susanna; Raschi, Antonio</p> <p>2007-12-01</p> <p>We compared the water-use characteristics of co-occurring mature Quercus cerris L. and Quercus pubescens Willd. trees growing in resource-limited (mainly water) hilly habitats in Tuscany, Italy. The species differed in their distribution along soil water gradients and in their access to, and use of, water, even though the study year was wetter than average, though with a summer drought. Compared with Q. cerris, Q. pubescens had greater access to soil water (less negative predawn water potentials) and a more conservative water-use strategy based on its relatively low stomatal conductance, high instantaneous water-use efficiency, less negative midday water potential and high soil-to-leaf hydra