Climate change impacts on crop yield: evidence from China.

PubMed

Wei, Taoyuan; Cherry, Todd L; Glomrød, Solveig; Zhang, Tianyi

2014-11-15

When estimating climate change impact on crop yield, a typical assumption is constant elasticity of yield with respect to a climate variable even though the elasticity may be inconstant. After estimating both constant and inconstant elasticities with respect to temperature and precipitation based on provincial panel data in China 1980-2008, our results show that during that period, the temperature change contributes positively to total yield growth by 1.3% and 0.4% for wheat and rice, respectively, but negatively by 12% for maize. The impacts of precipitation change are marginal. We also compare our estimates with other studies and highlight the implications of the inconstant elasticities for crop yield, harvest and food security. We conclude that climate change impact on crop yield would not be an issue in China if positive impacts of other socio-economic factors continue in the future. Copyright © 2014 Elsevier B.V. All rights reserved.

Determination of the D{sup 0}{yields}K{sup -}{pi}{sup +}{pi}{sup 0} and D{sup 0}{yields}K{sup -}{pi}{sup +}{pi}{sup +}{pi}{sup -} coherence factors and average strong-phase differences using quantum-correlated measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lowrey, N.; Mehrabyan, S.; Selen, M.

The first measurements of the coherence factors (R{sub K{pi}}{sub {pi}{sup 0}} and R{sub K3{pi}}) and the average strong-phase differences ({delta}{sub D}{sup K{pi}}{sup {pi}{sup 0}} and {delta}{sub D}{sup K3{pi}}) for D{sup 0}{yields}K{sup -}{pi}{sup +}{pi}{sup 0} and D{sup 0}{yields}K{sup -}{pi}{sup +}{pi}{sup +}{pi}{sup -} are presented. These parameters can be used to improve the determination of the unitarity triangle angle {gamma} in B{sup -}{yields}DK{sup -} decays, where D is a D{sup 0} or D{sup 0} meson decaying to the same final state. The measurements are made using quantum-correlated, fully reconstructed D{sup 0}D{sup 0} pairs produced in e{sup +}e{sup -} collisions at the {psi}(3770)more » resonance. The measured values are: R{sub K{pi}}{sub {pi}{sup 0}}=0.84{+-}0.07, {delta}{sub D}{sup K{pi}}{sup {pi}{sup 0}}=(227{sub -17}{sup +14}) deg., R{sub K3{pi}}=0.33{sub -0.23}{sup +0.20}, and {delta}{sub D}{sup K3{pi}}=(114{sub -23}{sup +26}) deg. These results indicate significant coherence in the decay D{sup 0}{yields}K{sup -}{pi}{sup +}{pi}{sup 0}, whereas lower coherence is observed in the decay D{sup 0}{yields}K{sup -}{pi}{sup +}{pi}{sup +}{pi}{sup -}. The analysis also results in a small improvement in the knowledge of other D-meson parameters, in particular, the strong-phase difference for D{sup 0}{yields}K{sup -}{pi}{sup +}, {delta}{sub D}{sup K{pi}}, and the mixing parameter y.« less

Evidence for Ni-56 yields Co-56 yields Fe-56 decay in type Ia supernovae

NASA Technical Reports Server (NTRS)

Kuchner, Marc J.; Kirshner, Robert P.; Pinto, Philip A.; Leibundgut, Bruno

1994-01-01

In the prevailing picture of Type Ia supernovae (SN Ia), their explosive burning produces Ni-56, and the radioactive decay chain Ni-56 yields Co-56 yields Fe-56 powers the subsequent emission. We test a central feature of this theory by measuring the relative strengths of a (Co III) emission feature near 5900 A and a (Fe III) emission feature near 4700 A. We measure 38 spectra from 13 SN Ia ranging from 48 to 310 days after maximum light. When we compare the observations with a simple multilevel calculation, we find that the observed Fe/Co flux ratio evolves as expected when the Fe-56/Co-56 abundance ratio follows from Ni-56 yields Co-56 yields Fe-56 decay. From this agreement, we conclude that the cobalt and iron atoms we observe through SN Ia emission lines are produced by the radioactive decay of Ni-56, just as predicted by a wide range of models for SN Ia explosions.

The alfalfa yield gap: A review of the evidence

USDA-ARS?s Scientific Manuscript database

Knowledge of feasibly attainable crop yields is needed for many purposes, from field-scale management to national policy decisions. For alfalfa (Medicago sativa L.), the most widely used estimates of yield in the US are whole-farm reports from the National Agriculture Statistics Service, which are b...

Evidence of N*(1535) resonance contribution in the pn{yields}d{phi} reaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cao Xu; Theoretical Physics Center for Sciences Facilities, Chinese Academy of Sciences, Beijing 100049; Graduate University of Chinese Academy of Sciences, Beijing 100049

2009-08-15

The N*(1535) resonance contributions to the pn{yields}d{phi} reaction are evaluated in an effective Lagrangian model. The {pi}-, {eta}-, and {rho}-meson exchange are considered. It is shown that the contributions from {pi}- and {rho}-meson exchange are dominant, while the contribution from {eta}-meson exchange is negligibly small. Our theoretical results reproduce the experimental data of both total cross section and angular distribution well. This is more evidence that the N*(1535) resonance has a large ss component leading to a large coupling to N{phi}, which may be the real origin of the Okubo-Zweig-Iizuka rule violation in the {pi}N and pN reactions.

Evidence for strong Breit interaction in dielectronic recombination of highly charged heavy ions.

PubMed

Nakamura, Nobuyuki; Kavanagh, Anthony P; Watanabe, Hirofumi; Sakaue, Hiroyuki A; Li, Yueming; Kato, Daiji; Currell, Fred J; Ohtani, Shunsuke

2008-02-22

Resonant strengths have been measured for dielectronic recombination of Li-like iodine, holmium, and bismuth using an electron beam ion trap. By observing the atomic number dependence of the state-resolved resonant strength, clear experimental evidence has been obtained that the importance of the generalized Breit interaction (GBI) effect on dielectronic recombination increases as the atomic number increases. In particular, it has been shown that the GBI effect is exceptionally strong for the recombination through the resonant state [1s2s(2)2p(1/2)](1).

Cavitation transition in the energy landscape: Distinct tensile yielding behavior in strongly and weakly attractive systems.

PubMed

Altabet, Y Elia; Fenley, Andreia L; Stillinger, Frank H; Debenedetti, Pablo G

2018-03-21

Particles with cohesive interactions display a tensile instability in the energy landscape at the Sastry density ρ S . The signature of this tensile limit is a minimum in the landscape equation of state, the pressure-density relationship of inherent structures sampled along a liquid isotherm. Our previous work [Y. E. Altabet, F. H. Stillinger, and P. G. Debenedetti, J. Chem. Phys. 145, 211905 (2016)] revisited the phenomenology of Sastry behavior and found that the evolution of the landscape equation of state with system size for particles with interactions typical of molecular liquids indicates the presence of an athermal first-order phase transition between homogeneous and fractured inherent structures, the latter containing several large voids. Here, we study how this tensile limit manifests itself for different interparticle cohesive strengths and identify two distinct regimes. Particles with sufficiently strong cohesion display an athermal first-order phase transition, consistent with our prior characterization. Weak cohesion also displays a tensile instability. However, the landscape equation of state for this regime is independent of system size, suggesting the absence of a first-order phase transition. An analysis of the voids suggests that yielding in the energy landscape of weakly cohesive systems is associated with the emergence of a highly interconnected network of small voids. While strongly cohesive systems transition from exclusively homogeneous to exclusively fractured configurations at ρ S in the thermodynamic limit, this interconnected network develops gradually, starting at ρ S , even at infinite system size.

Cavitation transition in the energy landscape: Distinct tensile yielding behavior in strongly and weakly attractive systems

NASA Astrophysics Data System (ADS)

Altabet, Y. Elia; Fenley, Andreia L.; Stillinger, Frank H.; Debenedetti, Pablo G.

2018-03-01

Particles with cohesive interactions display a tensile instability in the energy landscape at the Sastry density ρS. The signature of this tensile limit is a minimum in the landscape equation of state, the pressure-density relationship of inherent structures sampled along a liquid isotherm. Our previous work [Y. E. Altabet, F. H. Stillinger, and P. G. Debenedetti, J. Chem. Phys. 145, 211905 (2016)] revisited the phenomenology of Sastry behavior and found that the evolution of the landscape equation of state with system size for particles with interactions typical of molecular liquids indicates the presence of an athermal first-order phase transition between homogeneous and fractured inherent structures, the latter containing several large voids. Here, we study how this tensile limit manifests itself for different interparticle cohesive strengths and identify two distinct regimes. Particles with sufficiently strong cohesion display an athermal first-order phase transition, consistent with our prior characterization. Weak cohesion also displays a tensile instability. However, the landscape equation of state for this regime is independent of system size, suggesting the absence of a first-order phase transition. An analysis of the voids suggests that yielding in the energy landscape of weakly cohesive systems is associated with the emergence of a highly interconnected network of small voids. While strongly cohesive systems transition from exclusively homogeneous to exclusively fractured configurations at ρS in the thermodynamic limit, this interconnected network develops gradually, starting at ρS, even at infinite system size.

Large-scale Assessment Yields Evidence of Minimal Use of Reasoning Skills in Traditionally Taught Classes

NASA Astrophysics Data System (ADS)

Thacker, Beth

2017-01-01

Large-scale assessment data from Texas Tech University yielded evidence that most students taught traditionally in large lecture classes with online homework and predominantly multiple choice question exams, when asked to answer free-response (FR) questions, did not support their answers with logical arguments grounded in physics concepts. In addition to a lack of conceptual understanding, incorrect and partially correct answers lacked evidence of the ability to apply even lower level reasoning skills in order to solve a problem. Correct answers, however, did show evidence of at least lower level thinking skills as coded using a rubric based on Bloom's taxonomy. With the introduction of evidence-based instruction into the labs and recitations of the large courses and in a small, completely laboratory-based, hands-on course, the percentage of correct answers with correct explanations increased. The FR format, unlike other assessment formats, allowed assessment of both conceptual understanding and the application of thinking skills, clearly pointing out weaknesses not revealed by other assessment instruments, and providing data on skills beyond conceptual understanding for course and program assessment. Supported by National Institutes of Health (NIH) Challenge grant #1RC1GM090897-01.

Observation of B{sup +}{yields}{xi}{sub c}{sup 0}{lambda}{sub c}{sup +} and evidence for B{sup 0}{yields}{xi}{sub c}{sup -}{lambda}{sub c}{sup +}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chistov, R.; Aushev, T.; Balagura, V.

We report the first observation of the decay B{sup +}{yields}{xi}{sub c}{sup 0}{lambda}{sub c}{sup +} with a significance of 8.7{sigma} and evidence for the decay B{sup 0}{yields}{xi}{sub c}{sup -}{lambda}{sub c}{sup +} with a significance of 3.8{sigma}. The product B(B{sup +}{yields}{xi}{sub c}{sup 0}{lambda}{sub c}{sup +})xB({xi}{sub c}{sup 0}{yields}{xi}{sup +}{pi}{sup -}) is measured to be (4.8{sub -0.9}{sup +1.0}{+-}1.1{+-}1.2)x10{sup -5}, and B(B{sup 0}{yields}{xi}{sub c}{sup -}{lambda}{sub c}{sup +})xB({xi}{sub c}{sup -}{yields}{xi}{sup +}{pi}{sup -}{pi}{sup -}) is measured to be (9.3{sub -2.8}{sup +3.7}{+-}1.9{+-}2.4)x10{sup -5}. The errors are statistical, systematic and the error of the {lambda}{sub c}{sup +}{yields}pK{sup -}{pi}{sup +} branching fraction, respectively. The decay B{sup +}{yields}{xi}{sub c}{sup 0}{lambda}{sub c}{supmore » +} is the first example of a two-body exclusive B{sup +} decay into two charmed baryons. The data used for this analysis was accumulated at the {upsilon}(4S) resonance, using the Belle detector at the e{sup +}e{sup -} asymmetric-energy collider KEKB. The integrated luminosity of the data sample is equal to 357 fb{sup -1}, corresponding to 386x10{sup 6} BB pairs.« less

Meta-analysis of climate impacts and uncertainty on crop yields in Europe

NASA Astrophysics Data System (ADS)

Knox, Jerry; Daccache, Andre; Hess, Tim; Haro, David

2016-11-01

Future changes in temperature, rainfall and soil moisture could threaten agricultural land use and crop productivity in Europe, with major consequences for food security. We assessed the projected impacts of climate change on the yield of seven major crop types (viz wheat, barley, maize, potato, sugar beet, rice and rye) grown in Europe using a systematic review (SR) and meta-analysis of data reported in 41 original publications from an initial screening of 1748 studies. Our approach adopted an established SR procedure developed by the Centre for Evidence Based Conservation constrained by inclusion criteria and defined methods for literature searches, data extraction, meta-analysis and synthesis. Whilst similar studies exist to assess climate impacts on crop yield in Africa and South Asia, surprisingly, no comparable synthesis has been undertaken for Europe. Based on the reported results (n = 729) we show that the projected change in average yield in Europe for the seven crops by the 2050s is +8%. For wheat and sugar beet, average yield changes of +14% and +15% are projected, respectively. There were strong regional differences with crop impacts in northern Europe being higher (+14%) and more variable compared to central (+6%) and southern (+5) Europe. Maize is projected to suffer the largest negative mean change in southern Europe (-11%). Evidence of climate impacts on yield was extensive for wheat, maize, sugar beet and potato, but very limited for barley, rice and rye. The implications for supporting climate adaptation policy and informing climate impacts crop science research in Europe are discussed.

Negative impacts of climate change on cereal yields: statistical evidence from France

NASA Astrophysics Data System (ADS)

Gammans, Matthew; Mérel, Pierre; Ortiz-Bobea, Ariel

2017-05-01

In several world regions, climate change is predicted to negatively affect crop productivity. The recent statistical yield literature emphasizes the importance of flexibly accounting for the distribution of growing-season temperature to better represent the effects of warming on crop yields. We estimate a flexible statistical yield model using a long panel from France to investigate the impacts of temperature and precipitation changes on wheat and barley yields. Winter varieties appear sensitive to extreme cold after planting. All yields respond negatively to an increase in spring-summer temperatures and are a decreasing function of precipitation about historical precipitation levels. Crop yields are predicted to be negatively affected by climate change under a wide range of climate models and emissions scenarios. Under warming scenario RCP8.5 and holding growing areas and technology constant, our model ensemble predicts a 21.0% decline in winter wheat yield, a 17.3% decline in winter barley yield, and a 33.6% decline in spring barley yield by the end of the century. Uncertainty from climate projections dominates uncertainty from the statistical model. Finally, our model predicts that continuing technology trends would counterbalance most of the effects of climate change.

Evidence for B{sup 0}{yields}{rho}{sup 0}{rho}{sup 0} Decays and Implications for the Cabibbo-Kobayashi-Maskawa Angle {alpha}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aubert, B.; Bona, M.; Boutigny, D.

2007-03-16

We search for the decays B{sup 0}{yields}{rho}{sup 0}{rho}{sup 0}, B{sup 0}{yields}{rho}{sup 0}f{sub 0}(980), and B{sup 0}{yields}f{sub 0}(980)f{sub 0}(980) in a sample of about 384x10{sup 6} {upsilon}(4S){yields}BB decays collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at Stanford Linear Accelerator Center. We find evidence for B{sup 0}{yields}{rho}{sup 0}{rho}{sup 0} with 3.5{sigma} significance and measure the branching fraction B=(1.07{+-}0.33{+-}0.19)x10{sup -6} and longitudinal polarization fraction f{sub L}=0.87{+-}0.13{+-}0.04, where the first uncertainty is statistical, and the second is systematic. The uncertainty on the Cabibbo-Kobayashi-Maskawa quark-mixing matrix unitarity angle {alpha} due to penguin contributions in B{yields}{rho}{rho} decays is 18 deg.more » at the 1{sigma} level. We also set upper limits on the B{sup 0}{yields}{rho}{sup 0}f{sub 0}(980) and B{sup 0}{yields}f{sub 0}(980)f{sub 0}(980) decay rates.« less

Grass-legume mixtures sustain strong yield advantage over monocultures under cool maritime growing conditions over a period of 5 years.

PubMed

Helgadóttir, Áslaug; Suter, Matthias; Gylfadóttir, Thórey Ó; Kristjánsdóttir, Thórdís A; Lüscher, Andreas

2018-05-22

Grassland-based livestock systems in cool maritime regions are commonly dominated by grass monocultures receiving relatively high levels of fertilizer. The current study investigated whether grass-legume mixtures can improve the productivity, resource efficiency and robustness of yield persistence of cultivated grassland under extreme growing conditions over a period of 5 years. Monocultures and mixtures of two grasses (Phleum pratense and Festuca pratensis) and two legumes (Trifolium pratense and Trifolium repens), one of which was fast establishing and the other temporally persistent, were sown in a field trial. Relative abundance of the four species in the mixtures was systematically varied at sowing. The plots were maintained under three N levels (20, 70 and 220 kg N ha-1 year-1) and harvested twice a year for five consecutive years. Yields of individual species and interactions between all species present were modelled to estimate the species diversity effects. Significant positive diversity effects in all individual years and averaged across the 5 years were observed. Across years, the four-species equi-proportional mixture was 71 % (N20: 20 kg N ha-1 year-1) and 51 % (N70: 70 kg N ha-1 year-1) more productive than the average of monocultures, and the highest yielding mixture was 36 % (N20) and 39 % (N70) more productive than the highest yielding monoculture. Importantly, diversity effects were also evident at low relative abundances of either species group, grasses or legumes in the mixture. Mixtures suppressed weeds significantly better than monocultures consistently during the course of the experiment at all N levels. The results show that even in the less productive agricultural systems in the cool maritime regions grass-legume mixtures can contribute substantially and persistently to a more sustainable agriculture. Positive grass-legume interactions suggest that symbiotic N2 fixation is maintained even under these marginal conditions, provided that

Ionization Study of Isomeric Molecules in Strong-field Laser Pulses

DOE PAGES

Zigo, Stefan; Le, Anh-Thu; Timilsina, Pratap; ...

2017-02-10

Through the use of the technique of time-of-flight mass spectroscopy, we obtain strong-field ionization yields for randomly oriented 1,2-dichloroethylene (1,2-DCE) (C 2H 2Cl 2) and 2-butene (C 4H 8). Here, we are interested in studying the effect of conformal structure in strong-field ionization and, in particular, the role of molecular polarity. That is, we can perform strong-field ionization studies in polar vs non-polar molecules that have the same chemical composition. Here, we report our findings through the ionization yields and the ratio (trans/cis) of each stereoisomer pair as a function of intensity.

World Health Organization strong recommendations based on low-quality evidence (study quality) are frequent and often inconsistent with GRADE guidance.

PubMed

Alexander, Paul E; Brito, Juan P; Neumann, Ignacio; Gionfriddo, Michael R; Bero, Lisa; Djulbegovic, Benjamin; Stoltzfus, Rebecca; Montori, Victor M; Norris, Susan L; Schünemann, Holger J; Guyatt, Gordon H

2016-04-01

In 2007 the World Health Organization (WHO) adopted the GRADE system for development of public health guidelines. Previously we found that many strong recommendations issued by WHO are based on evidence for which there is only low or very low confidence in the estimates of effect (discordant recommendations). GRADE guidance indicates that such discordant recommendations are rarely appropriate but suggests five paradigmatic situations in which discordant recommendations may be warranted. We sought to provide insight into the many discordant recommendations in WHO guidelines. We examined all guidelines that used the GRADE method and were approved by the WHO Guideline Review Committee between 2007 and 2012. Teams of reviewers independently abstracted data from eligible guidelines and classified recommendations either into one of the five paradigms for appropriately-formulated discordant recommendations or into three additional categories in which discordant recommendations were inconsistent with GRADE guidance: 1) the evidence warranted moderate or high confidence (a misclassification of evidence) rather than low or very low confidence; 2) good practice statements; or 3) uncertainty in the estimates of effect would best lead to a conditional (weak) recommendation. The 33 eligible guidelines included 160 discordant recommendations, of which 98 (61.3%) addressed drug interventions and 132 (82.5%) provided some rationale (though not entirely explicit at times) for the strong recommendation. Of 160 discordant recommendations, 25 (15.6%) were judged consistent with one of the five paradigms for appropriate recommendations; 33 (21%) were based on evidence warranting moderate or high confidence in the estimates of effect; 29 (18%) were good practice statements; and 73 (46%) warranted a conditional, rather than a strong recommendation. WHO discordant recommendations are often inconsistent with GRADE guidance, possibly threatening the integrity of the process. Further training

Local yield stress statistics in model amorphous solids

NASA Astrophysics Data System (ADS)

Barbot, Armand; Lerbinger, Matthias; Hernandez-Garcia, Anier; García-García, Reinaldo; Falk, Michael L.; Vandembroucq, Damien; Patinet, Sylvain

2018-03-01

We develop and extend a method presented by Patinet, Vandembroucq, and Falk [Phys. Rev. Lett. 117, 045501 (2016), 10.1103/PhysRevLett.117.045501] to compute the local yield stresses at the atomic scale in model two-dimensional Lennard-Jones glasses produced via differing quench protocols. This technique allows us to sample the plastic rearrangements in a nonperturbative manner for different loading directions on a well-controlled length scale. Plastic activity upon shearing correlates strongly with the locations of low yield stresses in the quenched states. This correlation is higher in more structurally relaxed systems. The distribution of local yield stresses is also shown to strongly depend on the quench protocol: the more relaxed the glass, the higher the local plastic thresholds. Analysis of the magnitude of local plastic relaxations reveals that stress drops follow exponential distributions, justifying the hypothesis of an average characteristic amplitude often conjectured in mesoscopic or continuum models. The amplitude of the local plastic rearrangements increases on average with the yield stress, regardless of the system preparation. The local yield stress varies with the shear orientation tested and strongly correlates with the plastic rearrangement locations when the system is sheared correspondingly. It is thus argued that plastic rearrangements are the consequence of shear transformation zones encoded in the glass structure that possess weak slip planes along different orientations. Finally, we justify the length scale employed in this work and extract the yield threshold statistics as a function of the size of the probing zones. This method makes it possible to derive physically grounded models of plasticity for amorphous materials by directly revealing the relevant details of the shear transformation zones that mediate this process.

Tensile Yielding of Multi-Wall Carbon Nanotube

NASA Technical Reports Server (NTRS)

Wei, Chenyu; Cho, Kyeongjae; Srivastava, Deepak; Parks, John W. (Technical Monitor)

2002-01-01

The tensile yielding of multiwall carbon nanotubes (MWCNTs) has been studied using Molecular Dynamics simulations and a Transition State Theory based model. We find a strong dependence of the yielding on the strain rate. A critical strain rate has been predicted above/below which yielding strain of a MWCNT is larger/smaller than that of the corresponding single-wall carbon nanotubes. At experimentally feasible strain rate of 1% /hour and T = 300K, the yield strain of a MWCNT is estimated to be about 3-4 % higher than that of an equivalent SWCNT (Single Wall Carbon Nanotube), in good agreement with recent experimental observations.

Evidence for compensatory photosynthetic and yield response of soybeans to aphid herbivory

DOE PAGES

Kucharik, Christopher J.; Mork, Amelia C.; Meehan, Timothy D.; ...

2016-04-13

The soybean aphid, Aphis glycines Matsumura, an exotic species in North America that has been detected in 21 U.S. states and Canada, is a major pest for soybean that can reduce maximum photosynthetic capacity and yields. Our existing knowledge is based on relatively few studies that do not span a wide variety of environmental conditions, and often focus on relatively high and damaging population pressure. We examined the effects of varied populations and duration of soybean aphids on soybean photosynthetic rates and yield in two experiments. In a 2011 field study, we found that plants with low cumulative aphid daysmore » (CAD, less than 2,300) had higher yields than plants not experiencing significant aphid pressure, suggesting a compensatory growth response to low aphid pressure. This response did not hold at higher CAD, and yields declined. In a 2013 controlled-environment greenhouse study, soybean plants were well-watered and fertilized with nitrogen (N), and aphid populations were manipulated to reach moderate to high levels (8,000–50,000 CAD). Plants tolerated these population levels when aphids were introduced during the vegetative or reproductive phenological stages of the plant, showing no significant reduction in yield. Leaf N concentration and CAD were positively and significantly correlated with increasing ambient photosynthetic rates. Our findings suggest that, given the right environmental conditions, modern soybean plants can withstand higher aphid pressure than previously assumed. Moreover, soybean plants also responded positively through a compensatory photosynthetic effect to moderate population pressure, contributing to stable or increased yield.« less

Xenon Sputter Yield Measurements for Ion Thruster Materials

NASA Technical Reports Server (NTRS)

Williams, John D.; Gardner, Michael M.; Johnson, Mark L.; Wilbur, Paul J.

2003-01-01

In this paper, we describe a technique that was used to measure total and differential sputter yields of materials important to high specific impulse ion thrusters. The heart of the technique is a quartz crystal monitor that is swept at constant radial distance from a small target region where a high current density xenon ion beam is aimed. Differential sputtering yields were generally measured over a full 180 deg arc in a plane that included the beam centerline and the normal vector to the target surface. Sputter yield results are presented for a xenon ion energy range from 0.5 to 10 keV and an angle of incidence range from 0 deg to 70 deg from the target surface normal direction for targets consisting of molybdenum, titanium, solid (Poco) graphite, and flexible graphite (grafoil). Total sputter yields are calculated using a simple integration procedure and comparisons are made to sputter yields obtained from the literature. In general, the agreement between the available data is good. As expected for heavy xenon ions, the differential and total sputter yields are found to be strong functions of angle of incidence. Significant under- and over-cosine behavior is observed at low- and high-ion energies, respectively. In addition, strong differences in differential yield behavior are observed between low-Z targets (C and Ti) and high-Z targets (Mo). Curve fits to the differential sputter yield data are provided. They should prove useful to analysts interested in predicting the erosion profiles of ion thruster components and determining where the erosion products re-deposit.

Starting Strong: Evidence-­Based Early Literacy Practices

ERIC Educational Resources Information Center

Blamey, Katrin; Beauchat, Katherine

2016-01-01

Four evidence-based instructional approaches create an essential resource for any early literacy teacher or coach. Improve your teaching practices in all areas of early literacy. Use four proven instructional approaches--standards based, evidenced based, assessment based, and student based--to improve their teaching practice in all areas of early…

Evidence against a strong thermal inversion in HD 209458b from high-dispersion spectroscopy

NASA Astrophysics Data System (ADS)

Schwarz, Henriette; Brogi, Matteo; de Kok, Remco; Birkby, Jayne; Snellen, Ignas

2015-04-01

Context. Broadband secondary-eclipse measurements of strongly irradiated hot Jupiters have indicated the existence of atmospheric thermal inversions, but their presence is difficult to determine from broadband measurements because of degeneracies between molecular abundances and temperature structure. Furthermore, the primary mechanisms that drive the inversion layers in hot-Jupiter atmospheres are unknown. This question cannot be answered without reliable identification of thermal inversions. Aims: We apply high-resolution (R = 100 000) infrared spectroscopy to probe the temperature-pressure profile of HD 209458b. This bright, transiting hot-Jupiter has long been considered the gold standard for a hot Jupiter with an inversion layer, but this has been challenged in recent publications. Methods: We observed the thermal dayside emission of HD 209458b with the CRyogenic Infra-Red Echelle Spectrograph (CRIRES) on the Very Large Telescope during three nights, targeting the carbon monoxide band at 2.3 μm. Thermal inversions give rise to emission features, which means that detecting emission lines in the planetary spectrum, as opposed to absorption lines, would be direct evidence of a region in which the temperature increases with altitude. Results: We do not detect any significant absorption or emission of CO in the dayside spectrum of HD 209458b, although cross-correlation with template spectra either with CO absorption lines or with weak emission at the core of the lines show a low-significance correlation signal with asignal - to - noiseratioof ~3-3.5. Models with strong CO emission lines show a weak anti-correlation with similar or lower significance levels. Furthermore, we found no evidence of absorption or emission from H2O at these wavelengths. Conclusions: The non-detection of CO in the dayside spectrum of HD 209458b is interesting in light of a previous CO detection in the transmission spectrum. That there is no signal indicates that HD 209458b either has a

Groundwater subsidies and penalties to corn yield

NASA Astrophysics Data System (ADS)

Zipper, S. C.; Booth, E.; Loheide, S. P.

2013-12-01

Proper water management is critical to closing yield gaps (observed yield below potential yield) as global populations continue to expand. However, the impacts of shallow groundwater on crop production and surface processes are poorly understood. The presence of groundwater within or just below the root zone has the potential to cause (via oxygen stress in poorly drained soils) or eliminate (via water supply in dry regions) yield gaps. The additional water use by a plant in the presence of shallow groundwater, compared to free drainage conditions, is called the groundwater subsidy; the depth at which the groundwater subsidy is greatest is the optimal depth to groundwater (DTGW). In wet years or under very shallow water table conditions, the groundwater subsidy is likely to be negative due to increased oxygen stress, and can be thought of as a groundwater penalty. Understanding the spatial dynamics of groundwater subsidies/penalties and how they interact with weather is critical to making sustainable agricultural and land-use decisions under a range of potential climates. Here, we examine patterns of groundwater subsidies and penalties in two commercial cornfields in the Yahara River Watershed, an urbanizing agricultural watershed in south-central Wisconsin. Water table levels are generally rising in the region due to a long-term trend of increasing precipitation over the last several decades. Biophysical indicators tracked throughout both the 2012 and 2013 growing seasons show a strong response to variable groundwater levels on a field scale. Sections of the field with optimal DTGW exhibit consistently higher stomatal conductance rates, taller canopies and higher leaf area index, higher ET rates, and higher pollination success rates. Patterns in these biophysical lines of evidence allow us to pinpoint specific periods within the growing season that plants were experiencing either oxygen or water stress. Most importantly, groundwater subsidies and penalties are

Phosphorus, zinc, and boron influence yield components in Earliglow strawberry

DOE Office of Scientific and Technical Information (OSTI.GOV)

May, G.M.; Pritts, M.P.

1993-01-01

The main effects and interactions of soil-applied P, B, and Zn on yield and its components were examined in the field at two pH levels with Earliglow' strawberries (Fragaria ananassa Duch.). Applied nutrients had significant effects on several yield components, but responses depended on the levels of other nutrients or the soil pH. At a soil pH of 5.5, yield responded linearly to B and quadratically to P. At pH 6.5, P interacted with B and Zn. Fruit count per inflorescence was the yield component most strongly associated with yield, followed by individual fruit weight. However, these two yield componentsmore » responded differently to soil-applied nutrients. Foliar nutrient levels generally did not increase with the amount of applied nutrient, but often an applied nutrient had a strong effect on the level of another nutrient. Leaf nutrient levels were often correlated with fruit levels, but foliar and fruit levels at harvest were not related to reproductive performance. The study identifies some of the problems inherent in using foliar nutrient levels to predict a yield response and demonstrates how plant responses to single nutrients depend on soil chemistry and the presence of other nutrients.« less

Linear unmixing of multidate hyperspectral imagery for crop yield estimation

USDA-ARS?s Scientific Manuscript database

In this paper, we have evaluated an unsupervised unmixing approach, vertex component analysis (VCA), for the application of crop yield estimation. The results show that abundance maps of the vegetation extracted by the approach are strongly correlated to the yield data (the correlation coefficients ...

Climate Change and ENSO Effects on Southeastern US Climate Patterns and Maize Yield.

PubMed

Mourtzinis, Spyridon; Ortiz, Brenda V; Damianidis, Damianos

2016-07-19

Climate change has a strong influence on weather patterns and significantly affects crop yields globally. El Niño Southern Oscillation (ENSO) has a strong influence on the U.S. climate and is related to agricultural production variability. ENSO effects are location-specific and in southeastern U.S. strongly connect with climate variability. When combined with climate change, the effects on growing season climate patterns and crop yields might be greater than expected. In our study, historical monthly precipitation and temperature data were coupled with non-irrigated maize yield data (33-43 years depending on the location) to show a potential yield suppression of ~15% for one °C increase in southeastern U.S. growing season maximum temperature. Yield suppression ranged between -25 and -2% among locations suppressing the southeastern U.S. average yield trend since 1981 by 17 kg ha(-1)year(-1) (~25%), mainly due to year-to-year June temperature anomalies. Yields varied among ENSO phases from 1971-2013, with greater yields observed during El Niño phase. During La Niña years, maximum June temperatures were higher than Neutral and El Niño, whereas June precipitation was lower than El Niño years. Our data highlight the importance of developing location-specific adaptation strategies quantifying both, climate change and ENSO effects on month-specific growing season climate conditions.

Genetic Basis of Sjögren's Syndrome. How Strong is the Evidence?

PubMed Central

Anaya, Juan-Manuel; Delgado-Vega, Angélica María; Castiblanco, John

2006-01-01

Sjögren's syndrome (SS) is a late-onset chronic autoimmune disease (AID) affecting the exocrine glands, mainly the salivary and lachrymal. Genetic studies on twins with primary SS have not been performed, and only a few case reports describing twins have been published. The prevalence of primary SS in siblings has been estimated to be 0.09% while the reported general prevalence of the disease is approximately 0.1%. The observed aggregation of AIDs in families of patients with primary SS is nevertheless supportive for a genetic component in its etiology. In the absence of chromosomal regions identified by linkage studies, research has focused on candidate gene approaches (by biological plausibility) rather than on positional approaches. Ancestral haplotype 8.1 as well as TNF, IL10 and SSA1 loci have been consistently associated with the disease although they are not specific for SS. In this review, the genetic component of SS is discussed on the basis of three known observations: (a) age at onset and sex-dependent presentation, (b) familial clustering of the disease, and (c) dissection of the genetic component. Since there is no strong evidence for a specific genetic component in SS, a large international and collaborative study would be suitable to assess the genetics of this disorder. PMID:17162364

Anisotropic yield function capable of predicting eight ears

NASA Astrophysics Data System (ADS)

Yoon, J. H.; Cazacu, O.

2011-08-01

Deep drawing of a cylindrical cup from a rolled sheet is one of the typical forming operations where the effect of this anisotropy is most evident. Indeed, it is well documented in the literature that the number of ears and the shape of the earing pattern correlate with the r-values profile. For the strongly textured aluminum alloy AA 5042 (Numisheet Benchmark 2011), the experimental r-value distribution has two minima between the rolling and transverse direction data provided for this show that the r-value along the transverse direction (TD) is five times larger than the value corresponding to the rolling direction. Therefore, it is expected that there are more that the earing profile has more than four ears. The main objective of this paper is to assess whether a new form of CPB06ex2 yield function (Plunkett et al. (2008)) tailored for metals with no tension-compression asymmetry is capable of predicting more than four ears for this material.

Topics in strong Langmuir turbulence

NASA Technical Reports Server (NTRS)

Nicholson, D. R.

1983-01-01

Progress in two approaches to the study of strong Langmuir turbulence is reported. In two spatial dimensions, numerical solution of the Zakharov equations yields a steady state involving linear growth, linear damping, and a collection of coherent, long-lived entities which might loosely be called solitons. In one spatial dimension, a statistical theory is applied to the cubically nonlinear Schroedinger equation and is solved analytically in a special case.

Topics in strong Langmuir turbulence

NASA Technical Reports Server (NTRS)

Nicholson, D. R.

1982-01-01

Progress in two approaches to the study of strong Langmuir turbulence is reported. In two spatial dimensions, numerical solution of the Zakharov equations yields a steady state involving linear growth, linear damping, and a collection of coherent, long-lived entities which might loosely be called solitons. In one spatial dimension, a statistical theory is applied to the cubically nonlinear Schroedinger equation and is solved analytically in a special case.

Mechanical design of mussel byssus: material yield enhances attachment strength

PubMed

Bell; Gosline

1996-01-01

The competitive dominance of mussels in the wave-swept rocky intertidal zone is in part due to their ability to maintain a secure attachment. Mussels are tethered to the substratum by a byssus composed of numerous extracellular, collagenous threads secreted by the foot. Each byssal thread has three serially arranged parts: a corrugated proximal region, a smooth distal region and an adhesive plaque. This study examines the material and structural properties of the byssal threads of three mussel species: Mytilus californianus, M. trossulus, and M. galloprovincialis. Tensile tests in general reveal similar material properties among species: the proximal region has a lower initial modulus, a lower ultimate stress and a higher ultimate strain than the distal region. The distal region also yields at a stress well below its ultimate value. In whole thread tests, the proximal region and adhesive plaque are common sites of structural failure and are closely matched in strength, while the distal region appears to be excessively strong. We propose that the high strength of the distal region is the byproduct of a material designed to yield and extend before structural failure occurs. Experimental and theoretical evidence is presented suggesting that thread yield and extensibility provide two important mechanisms for increasing the overall attachment strength of the mussel: (1) the reorientation of threads towards the direction of applied load, and (2) the 'recruitment' of more threads into tension and the consequent distribution of applied load over a larger cross-sectional area, thereby reducing the stress on each thread. This distal region yield behavior is most striking for M. californianus and may be a key to its success in extreme wave-swept environments.

Improving the yield from fermentative hydrogen production.

PubMed

Kraemer, Jeremy T; Bagley, David M

2007-05-01

Efforts to increase H(2) yields from fermentative H(2) production include heat treatment of the inoculum, dissolved gas removal, and varying the organic loading rate. Although heat treatment kills methanogens and selects for spore-forming bacteria, the available evidence indicates H(2) yields are not maximized compared to bromoethanesulfonate, iodopropane, or perchloric acid pre-treatments and spore-forming acetogens are not killed. Operational controls (low pH, short solids retention time) can replace heat treatment. Gas sparging increases H(2) yields compared to un-sparged reactors, but no relationship exists between the sparging rate and H(2) yield. Lower sparging rates may improve the H(2) yield with less energy input and product dilution. The reasons why sparging improves H(2) yields are unknown, but recent measurements of dissolved H(2) concentrations during sparging suggest the assumption of decreased inhibition of the H(2)-producing enzymes is unlikely. Significant disagreement exists over the effect of organic loading rate (OLR); some studies show relatively higher OLRs improve H(2) yield while others show the opposite. Discovering the reasons for higher H(2) yields during dissolved gas removal and changes in OLR will help improve H(2) yields.

Strongly Coupled Tin-Halide Perovskites to Modulate Light Emission: Tunable 550-640 nm Light Emission (FWHM 36-80 nm) with a Quantum Yield of up to 6.4.

PubMed

Chen, Min-Yi; Lin, Jin-Tai; Hsu, Chia-Shuo; Chang, Chung-Kai; Chiu, Ching-Wen; Chen, Hao Ming; Chou, Pi-Tai

2018-05-01

Colloidal perovskite quantum dots represent one of the most promising materials for applications in solar cells and photoluminescences. These devices require a low density of crystal defects and a high yield of photogenerated carriers, which are difficult to realize in tin-halide perovskite because of the intrinsic instability of tin during nucleation. Here, an enhancement in the luminescent property of tin-halide perovskite nanoplates (TPNPs) that are composed of strongly coupled layered structures with the chemical formula of PEA 2 SnX 4 (PEA = C 6 H 5 (CH 2 ) 2 NH 3 , X = Br, I) is reported. TPNPs (X = I) show an emission at a wavelength of 640 nm, with high quantum yield of 6.40 ± 0.14% and full width at half maximum (FWHM) as small as 36 nm. The presence of aliphatic carboxylic acid is found to play a key role in reducing the tin perovskite defect density, which significantly improves the emission intensity and stability of TPNPs. Upon mixing iodo- and bromo- precursors, the emission wavelength is successfully tuned from 640 nm (PEA 2 SnI 4 ) to 550 nm (PEA 2 SnBr 4 ), with a corresponding emission quantum yield and FWHM of 0.16-6.40% and 36-80 nm, respectively. The results demonstrate a major advance for the emission yield and tunability of tin-halide perovskites. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Water limits to closing yield gaps

NASA Astrophysics Data System (ADS)

Davis, Kyle Frankel; Rulli, Maria Cristina; Garrassino, Francesco; Chiarelli, Davide; Seveso, Antonio; D'Odorico, Paolo

2017-01-01

Agricultural intensification is often seen as a suitable approach to meet the growing demand for agricultural products and improve food security. It typically entails the use of fertilizers, new cultivars, irrigation, and other modern technology. In regions of the world affected by seasonal or chronic water scarcity, yield gap closure is strongly dependent on irrigation (blue water). Global yield gap assessments have often ignored whether the water required to close the yield gap is locally available. Here we perform a gridded global analysis (10 km resolution) of the blue water consumption that is needed annually to close the yield gap worldwide and evaluate the associated pressure on renewable freshwater resources. We find that, to close the yield gap, human appropriation of freshwater resources for irrigation would have to increase at least by 146%. Most study countries would experience at least a doubling in blue water requirement, with 71% of the additional blue water being required by only four crops - maize, rice, soybeans, and wheat. Further, in some countries (e.g., Algeria, Morocco, Syria, Tunisia, and Yemen) the total volume of blue water required for yield gap closure would exceed sustainable levels of freshwater consumption (i.e., 40% of total renewable surface and groundwater resources).

Exploration of the Transition from the Hydrodynamic-like to the Strongly Kinetic Regime in Shock-Driven Implosions

DOE PAGES

Rosenberg, M. J.; Rinderknecht, H. G.; Hoffman, N. M.; ...

2014-05-05

Clear evidence of the transition from hydrodynamiclike to strongly kinetic shock-driven implosions is, for the first time, revealed and quantitatively assessed. Implosions with a range of initial equimolar D 3He gas densities show that as the density is decreased, hydrodynamic simulations strongly diverge from and increasingly over-predict the observed nuclear yields, from a factor of ~2 at 3.1 mg/cm 3 to a factor of 100 at 0.14 mg/cm 3. (The corresponding Knudsen number, the ratio of ion mean-free path to minimum shell radius, varied from 0.3 to 9; similarly, the ratio of fusion burn duration to ion diffusion time, anothermore » figure of merit of kinetic effects, varied from 0.3 to 14.) This result is shown to be unrelated to the effects of hydrodynamic mix. As a first step to garner insight into this transition, a reduced ion kinetic (RIK) model that includes gradient-diffusion and loss-term approximations to several transport processes was implemented within the framework of a one-dimensional radiation-transport code. After empirical calibration, the RIK simulations reproduce the observed yield trends, largely as a result of ion diffusion and the depletion of the reacting tail ions.« less

The Z {yields} cc-bar {yields} {gamma}{gamma}*, Z {yields} bb-bar {yields} {gamma}{gamma}* triangle diagrams and the Z {yields} {gamma}{psi}, Z {yields} {gamma}Y decays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Achasov, N. N., E-mail: achasov@math.nsc.ru

2011-03-15

The approach to the Z {yields} {gamma}{psi} and Z {yields} {gamma}Y decay study is presented in detail, based on the sum rules for the Z {yields} cc-bar {yields} {gamma}{gamma}* and Z {yields} bb-bar {yields} {gamma}{gamma}* amplitudes and their derivatives. The branching ratios of the Z {yields} {gamma}{psi} and Z {yields} {gamma}Y decays are calculated for different hypotheses on saturation of the sum rules. The lower bounds of {Sigma}{sub {psi}} BR(Z {yields} {gamma}{psi}) = 1.95 Multiplication-Sign 10{sup -7} and {Sigma}{sub {upsilon}} BR(Z {yields} {gamma}Y) = 7.23 Multiplication-Sign 10{sup -7} are found. Deviations from the lower bounds are discussed, including the possibilitymore » of BR(Z {yields} {gamma}J/{psi}(1S)) {approx} BR(Z {yields} {gamma}Y(1S)) {approx} 10{sup -6}, that could be probably measured in LHC. The angular distributions in the Z {yields} {gamma}{psi} and Z {yields} {gamma}Y decays are also calculated.« less

Strong evidence for the presence of the tick Hyalomma marginatum Koch, 1844 in southern continental France.

PubMed

Vial, Laurence; Stachurski, Frédéric; Leblond, Agnès; Huber, Karine; Vourc'h, Gwenaël; René-Martellet, Magalie; Desjardins, Isabelle; Balança, Gilles; Grosbois, Vladimir; Pradier, Sophie; Gély, Marie; Appelgren, Anaïs; Estrada-Peña, Agustin

2016-10-01

Hyalomma ticks can transmit several human and animal pathogens in Eurasia and Africa. Interest in Hyalomma marginatum has increased since the recent (re)emergence of Crimean-Congo Hemorrhagic fever in the Palearctic region. Until now, continental France has been considered free of this tick species. Nevertheless, the existence of incomplete and occasionally incorrect records has maintained confusion about its status. Based on several tick sampling campaigns conducted on horses and birds from 2007 to 2016, we provided very strong evidence for the presence of reproducing populations of H. marginatum in parts of southern continental France. We also confirmed the introduction of immature developmental stages of H. marginatum, as well as H. rufipes, into France probably through trans-Mediterranean bird migrations. Copyright © 2016. Published by Elsevier GmbH.

Photosynthetic limitation as a factor influencing yield in highbush blueberries (Vaccinium corymbosum) grown in a northern European environment.

PubMed

Petridis, Antonios; van der Kaay, Jeroen; Chrysanthou, Elina; McCallum, Susan; Graham, Julie; Hancock, Robert D

2018-05-25

Published evidence indicates that nearly 60% of blueberry-producing countries experience yield instability. Yield is a complex trait determined by genetic and environmental factors. Here, using physiological and biochemical approaches, we tested the hypothesis that yield instability results from year-to-year environmental variation that limits carbon assimilation, storage and partitioning. The data indicate that fruit development depends primarily on the daily production of non-structural carbohydrates by leaves, and there is no accumulation of a starch buffer to allow continuous ripening under conditions limiting for photosynthesis. Photosynthesis was saturated at moderate light irradiance and this was mainly due to stomatal and biochemical limitations. In a dynamic light environment, photosynthesis was further limited by slow stomatal response to increasing light. Finally, labelling with 13CO2 at specific stages of fruit development revealed a relatively even distribution of newly assimilated carbon between stems, roots and fruits, suggesting that the fruit is not a strong sink. We conclude that a significant component of yield variability results from limitations in photosynthetic efficiency that are compounded by an inability to accumulate starch reserves in blueberry storage tissues in a typical northern European environment. This work informs techniques for improving agronomic management and indicates key traits required for yield stability in such environments.

Photosynthetic limitation as a factor influencing yield in highbush blueberries (Vaccinium corymbosum) grown in a northern European environment

PubMed Central

van der Kaay, Jeroen; Chrysanthou, Elina; McCallum, Susan

2018-01-01

Abstract Published evidence indicates that nearly 60% of blueberry-producing countries experience yield instability. Yield is a complex trait determined by genetic and environmental factors. Here, using physiological and biochemical approaches, we tested the hypothesis that yield instability results from year-to-year environmental variation that limits carbon assimilation, storage and partitioning. The data indicate that fruit development depends primarily on the daily production of non-structural carbohydrates by leaves, and there is no accumulation of a starch buffer to allow continuous ripening under conditions limiting for photosynthesis. Photosynthesis was saturated at moderate light irradiance and this was mainly due to stomatal and biochemical limitations. In a dynamic light environment, photosynthesis was further limited by slow stomatal response to increasing light. Finally, labelling with 13CO2 at specific stages of fruit development revealed a relatively even distribution of newly assimilated carbon between stems, roots and fruits, suggesting that the fruit is not a strong sink. We conclude that a significant component of yield variability results from limitations in photosynthetic efficiency that are compounded by an inability to accumulate starch reserves in blueberry storage tissues in a typical northern European environment. This work informs techniques for improving agronomic management and indicates key traits required for yield stability in such environments. PMID:29590429

Molecular Probe Dynamics Reveals Suppression of Ice-Like Regions in Strongly Confined Supercooled Water

PubMed Central

Banerjee, Debamalya; Bhat, Shrivalli N.; Bhat, Subray V.; Leporini, Dino

2012-01-01

The structure of the hydrogen bond network is a key element for understanding water's thermodynamic and kinetic anomalies. While ambient water is strongly believed to be a uniform, continuous hydrogen-bonded liquid, there is growing consensus that supercooled water is better described in terms of distinct domains with either a low-density ice-like structure or a high-density disordered one. We evidenced two distinct rotational mobilities of probe molecules in interstitial supercooled water of polycrystalline ice [Banerjee D, et al. (2009) ESR evidence for 2 coexisting liquid phases in deeply supercooled bulk water. Proc Natl Acad Sci USA 106: 11448–11453]. Here we show that, by increasing the confinement of interstitial water, the mobility of probe molecules, surprisingly, increases. We argue that loose confinement allows the presence of ice-like regions in supercooled water, whereas a tighter confinement yields the suppression of this ordered fraction and leads to higher fluidity. Compelling evidence of the presence of ice-like regions is provided by the probe orientational entropy barrier which is set, through hydrogen bonding, by the configuration of the surrounding water molecules and yields a direct measure of the configurational entropy of the same. We find that, under loose confinement of supercooled water, the entropy barrier surmounted by the slower probe fraction exceeds that of equilibrium water by the melting entropy of ice, whereas no increase of the barrier is observed under stronger confinement. The lower limit of metastability of supercooled water is discussed. PMID:23049747

Scaling and Thermal Evolution of Internally Heated Planets: Yield Stress and Thermal History.

NASA Astrophysics Data System (ADS)

Weller, M. B.; Lenardic, A.; Moore, W. B.

2014-12-01

Using coupled 3D mantle convection and planetary tectonics models of bi-stable systems, we show how system behaviors for mobile-lid and stagnant-lid states scale as functions of internal heating rates (Q) and basal Ra (Rab). With parameter ranges for temperature- and depth-dependant viscosities: 1e4 - 3e4, Rab: 1e5- 3e5, Q: 0 - 100, and yield stress: 1e4 - 2e5, it can be shown the internal temperatures, velocities, heat fluxes, and system behaviors for mobile-lid and stagnant-lid states diverge, for equivalent parameter values, as a function of increasing Q. For the mobile-lid regime, yielding behavior in the upper boundary layer strongly influences the dynamics of the system. Internal temperatures, and consequently temperature-dependant viscosities, vary strongly as a function of yield stress for a given Q. The temperature distribution across the upper and lower mantles are sub-adiabatic for low to moderate yield stress, and adiabatic to super-adiabatic for high yield stresses. Across the parameter range considered, and for fixed yield stress, the Nu across the basal boundary (Nub) is positive and only weakly dependant on Q (varies by ~ 9%). Nub varies strongly as a function of yield stress (maximum variation of ~84%). Both mobile-lid velocities and lid-thicknesses are yield stress dependant for a given Q and Ra. In contrast to mobile-lids, the stagnant-lid regime is governed by the relative inefficiency of heat transport through the surface boundary layer. Internal temperatures are yield stress independent, and are on average 30% greater. Nub has a strong dependence on heating rates and surface boundary layer thicknesses. Within the parameter space considered, the maximum stagnant-lid Nub corresponds to the minimum mobile-lid Nub (for high yield stress), and decreases with increasing Q. For high Q, super-heated stagnant-lids may develop, with Nub< 0, and changes in trends for system behaviors. Planets with high levels of internal heating and/or high yield

SEARCHING FOR COOLING SIGNATURES IN STRONG LENSING GALAXY CLUSTERS: EVIDENCE AGAINST BARYONS SHAPING THE MATTER DISTRIBUTION IN CLUSTER CORES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blanchard, Peter K.; Bayliss, Matthew B.; McDonald, Michael

2013-07-20

The process by which the mass density profile of certain galaxy clusters becomes centrally concentrated enough to produce high strong lensing (SL) cross-sections is not well understood. It has been suggested that the baryonic condensation of the intracluster medium (ICM) due to cooling may drag dark matter to the cores and thus steepen the profile. In this work, we search for evidence of ongoing ICM cooling in the first large, well-defined sample of SL selected galaxy clusters in the range 0.1 < z < 0.6. Based on known correlations between the ICM cooling rate and both optical emission line luminositymore » and star formation, we measure, for a sample of 89 SL clusters, the fraction of clusters that have [O II]{lambda}{lambda}3727 emission in their brightest cluster galaxy (BCG). We find that the fraction of line-emitting BCGs is constant as a function of redshift for z > 0.2 and shows no statistically significant deviation from the total cluster population. Specific star formation rates, as traced by the strength of the 4000 A break, D{sub 4000}, are also consistent with the general cluster population. Finally, we use optical imaging of the SL clusters to measure the angular separation, R{sub arc}, between the arc and the center of mass of each lensing cluster in our sample and test for evidence of changing [O II] emission and D{sub 4000} as a function of R{sub arc}, a proxy observable for SL cross-sections. D{sub 4000} is constant with all values of R{sub arc}, and the [O II] emission fractions show no dependence on R{sub arc} for R{sub arc} > 10'' and only very marginal evidence of increased weak [O II] emission for systems with R{sub arc} < 10''. These results argue against the ability of baryonic cooling associated with cool core activity in the cores of galaxy clusters to strongly modify the underlying dark matter potential, leading to an increase in SL cross-sections.« less

Climate-Driven Crop Yield and Yield Variability and Climate Change Impacts on the U.S. Great Plains Agricultural Production.

PubMed

Kukal, Meetpal S; Irmak, Suat

2018-02-22

Climate variability and trends affect global crop yields and are characterized as highly dependent on location, crop type, and irrigation. U.S. Great Plains, due to its significance in national food production, evident climate variability, and extensive irrigation is an ideal region of investigation for climate impacts on food production. This paper evaluates climate impacts on maize, sorghum, and soybean yields and effect of irrigation for individual counties in this region by employing extensive crop yield and climate datasets from 1968-2013. Variability in crop yields was a quarter of the regional average yields, with a quarter of this variability explained by climate variability, and temperature and precipitation explained these in singularity or combination at different locations. Observed temperature trend was beneficial for maize yields, but detrimental for sorghum and soybean yields, whereas observed precipitation trend was beneficial for all three crops. Irrigated yields demonstrated increased robustness and an effective mitigation strategy against climate impacts than their non-irrigated counterparts by a considerable fraction. The information, data, and maps provided can serve as an assessment guide for planners, managers, and policy- and decision makers to prioritize agricultural resilience efforts and resource allocation or re-allocation in the regions that exhibit risk from climate variability.

Irrigation offsets wheat yield reductions from warming temperatures

NASA Astrophysics Data System (ADS)

Tack, Jesse; Barkley, Andrew; Hendricks, Nathan

2017-11-01

Temperature increases due to climate change are expected to cause substantial reductions in global wheat yields. However, uncertainty remains regarding the potential role for irrigation as an adaptation strategy to offset heat impacts. Here we utilize over 7000 observations spanning eleven Kansas field-trial locations, 180 varieties, and 29 years to show that irrigation significantly reduces the negative impact of warming temperatures on winter wheat yields. Dryland wheat yields are estimated to decrease about eight percent for every one-degree Celsius increase in temperature, yet irrigation completely offsets this negative impact in our sample. As in previous studies, we find that important interactions exist between heat stress and precipitation for dryland production. Here, uniquely, we observe both dryland and irrigated trials side-by-side at the same locations and find that precipitation does not provide the same reduction in heat stress as irrigation. This is likely to be because the timing, intensity, and volume of water applications influence wheat yields, so the ability to irrigate—rather than relying on rainfall alone—has a stronger influence on heat stress. We find evidence of extensive differences of water-deficit stress impacts across varieties. This provides some evidence of the potential for adapting to hotter and drier climate conditions using optimal variety selection. Overall, our results highlight the critical role of water management for future global food security. Water scarcity not only reduces crop yields through water-deficit stress, but also amplifies the negative effects of warming temperatures.

Strong coupling of collection of emitters on hyperbolic meta-material

NASA Astrophysics Data System (ADS)

Biehs, Svend-Age; Xu, Chenran; Agarwal, Girish S.

2018-04-01

Recently, considerable effort has been devoted to the realization of a strong coupling regime of the radiation matter interaction in the context of an emitter at a meta surface. The strong interaction is well realized in cavity quantum electrodynamics, which also show that strong coupling is much easier to realize using a collection of emitters. Keeping this in mind, we study if emitters on a hyperbolic meta materials can yield a strong coupling regime. We show that strong coupling can be realized for densities of emitters exceeding a critical value. A way to detect strong coupling between emitters and hyperbolic metamaterials is to use the Kretschman-Raether configuration. The strong coupling appears as the splitting of the reflectivity dip. In the weak coupling regime, the dip position shifts. The shift and splitting can be used to sense active molecules at surfaces.

Production yield of rare-earth ions implanted into an optical crystal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kornher, Thomas, E-mail: t.kornher@physik.uni-stuttgart.de; Xia, Kangwei; Kolesov, Roman

2016-02-01

Rare-earth (RE) ions doped into desired locations of optical crystals might enable a range of novel integrated photonic devices for quantum applications. With this aim, we have investigated the production yield of cerium and praseodymium by means of ion implantation. As a measure, the collected fluorescence intensity from both implanted samples and single centers was used. With a tailored annealing procedure for cerium, a yield up to 53% was estimated. Praseodymium yield amounts up to 91%. Such high implantation yield indicates a feasibility of creation of nanopatterned rare-earth doping and suggests strong potential of RE species for on-chip photonic devices.

What Is the Evidence for Physical Therapy Poststroke? A Systematic Review and Meta-Analysis

PubMed Central

Veerbeek, Janne Marieke; van Wegen, Erwin; van Peppen, Roland; van der Wees, Philip Jan; Hendriks, Erik; Rietberg, Marc; Kwakkel, Gert

2014-01-01

Background Physical therapy (PT) is one of the key disciplines in interdisciplinary stroke rehabilitation. The aim of this systematic review was to provide an update of the evidence for stroke rehabilitation interventions in the domain of PT. Methods and Findings Randomized controlled trials (RCTs) regarding PT in stroke rehabilitation were retrieved through a systematic search. Outcomes were classified according to the ICF. RCTs with a low risk of bias were quantitatively analyzed. Differences between phases poststroke were explored in subgroup analyses. A best evidence synthesis was performed for neurological treatment approaches. The search yielded 467 RCTs (N = 25373; median PEDro score 6 [IQR 5–7]), identifying 53 interventions. No adverse events were reported. Strong evidence was found for significant positive effects of 13 interventions related to gait, 11 interventions related to arm-hand activities, 1 intervention for ADL, and 3 interventions for physical fitness. Summary Effect Sizes (SESs) ranged from 0.17 (95%CI 0.03–0.70; I2 = 0%) for therapeutic positioning of the paretic arm to 2.47 (95%CI 0.84–4.11; I2 = 77%) for training of sitting balance. There is strong evidence that a higher dose of practice is better, with SESs ranging from 0.21 (95%CI 0.02–0.39; I2 = 6%) for motor function of the paretic arm to 0.61 (95%CI 0.41–0.82; I2 = 41%) for muscle strength of the paretic leg. Subgroup analyses yielded significant differences with respect to timing poststroke for 10 interventions. Neurological treatment approaches to training of body functions and activities showed equal or unfavorable effects when compared to other training interventions. Main limitations of the present review are not using individual patient data for meta-analyses and absence of correction for multiple testing. Conclusions There is strong evidence for PT interventions favoring intensive high repetitive task-oriented and task-specific training in all

Definition of architectural ideotypes for good yield capacity in Coffea canephora.

PubMed

Cilas, Christian; Bar-Hen, Avner; Montagnon, Christophe; Godin, Christophe

2006-03-01

Yield capacity is a target trait for selection of agronomically desirable lines; it is preferred to simple yields recorded over different harvests. Yield capacity is derived using certain architectural parameters used to measure the components of yield capacity. Observation protocols for describing architecture and yield capacity were applied to six clones of coffee trees (Coffea canephora) in a comparative trial. The observations were used to establish architectural databases, which were explored using AMAPmod, a software dedicated to the analyses of plant architecture data. The traits extracted from the database were used to identify architectural parameters for predicting the yield of the plant material studied. Architectural traits are highly heritable and some display strong genetic correlations with cumulated yield. In particular, the proportion of fruiting nodes at plagiotropic level 15 counting from the top of the tree proved to be a good predictor of yield over two fruiting cycles.

Sediment yields from small, steep coastal watersheds of California

USGS Publications Warehouse

Warrick, Jonathan A.; Melack, John M.; Goodridge, Blair M.

2015-01-01

Global inventories of sediment discharge to the ocean highlight the importance of small, steep watersheds (i.e., those having drainage areas less than 100,000 km2 and over 1000 m of relief) that collectively provide a dominant flux of sediment. The smallest of these coastal watersheds (e.g., those that have drainage areas less than 1000 km2) can represent a large portion of the drainage areas of active margin coasts, such as California’s coast, but remain almost universally unmonitored. Here we report on the suspended-sediment discharge of several small coastal watersheds (10-56 km2) of the Santa Ynez Mountains, California, that were found to have ephemeral discharge and suspended-sediment concentrations ranging between 1 and over 200,000 mgL-1. Sediment concentrations were weakly correlated with discharge (r2 = 0.10–0.25), and all types of hysteresis patterns were observed during high flows (clockwise, counterclockwise, no hysteresis, and complex). Sediment discharge varied strongly with time and was measurably elevated in one watershed following a wildfire. Although sediment yields varied by over 100-fold across the watersheds (e.g., 15 – 2100 tkm-2 yr -1during the relatively wet 2005 water year), the majority of sediment discharge (65-80%) occurred during only 1% of the time for all watersheds. Furthermore, sampling of dozens of high flow events provides evidence that sediment yields were generally related to peak discharge yields, although these relationships were not consistent across the watersheds. These results suggest that small watersheds of active margins can provide large fluxes of sediment to the coast, but that the rates and timing of this sediment discharge is more irregular in time – and thus more difficult to characterize – than the better monitored and studied watersheds that are 1000-100,000 km2.

High-Density SNP Screening of the Major Histocompatibility Complex in Systemic Lupus Erythematosus Demonstrates Strong Evidence for Independent Susceptibility Regions

PubMed Central

Barcellos, Lisa F.; May, Suzanne L.; Ramsay, Patricia P.; Quach, Hong L.; Lane, Julie A.; Nititham, Joanne; Noble, Janelle A.; Taylor, Kimberly E.; Quach, Diana L.; Chung, Sharon A.; Kelly, Jennifer A.; Moser, Kathy L.; Behrens, Timothy W.; Seldin, Michael F.; Thomson, Glenys; Harley, John B.; Gaffney, Patrick M.; Criswell, Lindsey A.

2009-01-01

A substantial genetic contribution to systemic lupus erythematosus (SLE) risk is conferred by major histocompatibility complex (MHC) gene(s) on chromosome 6p21. Previous studies in SLE have lacked statistical power and genetic resolution to fully define MHC influences. We characterized 1,610 Caucasian SLE cases and 1,470 parents for 1,974 MHC SNPs, the highly polymorphic HLA-DRB1 locus, and a panel of ancestry informative markers. Single-marker analyses revealed strong signals for SNPs within several MHC regions, as well as with HLA-DRB1 (global p = 9.99×10−16). The most strongly associated DRB1 alleles were: *0301 (odds ratio, OR = 2.21, p = 2.53×10−12), *1401 (OR = 0.50, p = 0.0002), and *1501 (OR = 1.39, p = 0.0032). The MHC region SNP demonstrating the strongest evidence of association with SLE was rs3117103, with OR = 2.44 and p = 2.80×10−13. Conditional haplotype and stepwise logistic regression analyses identified strong evidence for association between SLE and the extended class I, class I, class III, class II, and the extended class II MHC regions. Sequential removal of SLE–associated DRB1 haplotypes revealed independent effects due to variation within OR2H2 (extended class I, rs362521, p = 0.006), CREBL1 (class III, rs8283, p = 0.01), and DQB2 (class II, rs7769979, p = 0.003, and rs10947345, p = 0.0004). Further, conditional haplotype analyses demonstrated that variation within MICB (class I, rs3828903, p = 0.006) also contributes to SLE risk independent of HLA-DRB1*0301. Our results for the first time delineate with high resolution several MHC regions with independent contributions to SLE risk. We provide a list of candidate variants based on biologic and functional considerations that may be causally related to SLE risk and warrant further investigation. PMID:19851445

Development of buoyant currents in yield stress fluids

NASA Astrophysics Data System (ADS)

Rossi, P.; Karimfazli, I.

2017-11-01

Infinitesimal perturbations are known to decay in a motionless yield stress fluid. We present experimental evidence to reveal other mechanisms promoting free advection from a motionless background state. Development of natural convection in a cavity with differentially heated side-walls is investigated as a benchmark. Velocity and temperature fields are measured using particle image velocimetry/thermometry. We examine time evolution of the flow, compare experimental findings with theoretical predictions and comment on the striking features brought about by the yield stress.

Secondary electron emission yield from high aspect ratio carbon velvet surfaces

NASA Astrophysics Data System (ADS)

Jin, Chenggang; Ottaviano, Angelica; Raitses, Yevgeny

2017-11-01

The plasma electrons bombarding a plasma-facing wall surface can induce secondary electron emission (SEE) from the wall. A strong SEE can enhance the power losses by reducing the wall sheath potential and thereby increasing the electron flux from the plasma to the wall. The use of the materials with surface roughness and the engineered materials with surface architecture is known to reduce the effective SEE by trapping the secondary electrons. In this work, we demonstrate a 65% reduction of SEE yield using a velvet material consisting of high aspect ratio carbon fibers. The measurements of SEE yield for different velvet samples using the electron beam in vacuum demonstrate the dependence of the SEE yield on the fiber length and the packing density, which is strongly affected by the alignment of long velvet fibers with respect to the electron beam impinging on the velvet sample. The results of SEE measurements support the previous observations of the reduced SEE measured in Hall thrusters.

Assessing spatiotemporal variation of drought and its impact on maize yield in Northeast China

NASA Astrophysics Data System (ADS)

Guo, Enliang; Liu, Xingpeng; Zhang, Jiquan; Wang, Yongfang; Wang, Cailin; Wang, Rui; Li, Danjun

2017-10-01

In the context of global climate change, drought has become an important factor that affects the maize yield in China. To analyse the impact of drought on maize yield loss in Northeast China in current and future climate scenarios, the Composite Meteorological Drought Index (CI) is introduced to reconstruct the following drought indicators: drought accumulative days (DAD), drought accumulative intensity (DAI), and consecutive drought days (CDD). These three drought indicators are used to describe the three-dimensional characteristics of drought in this study. Sen's slope method and three-dimensional copula functions are adopted to analyse the variety of drought features, and Ensemble Empirical Mode Decomposition (EEMD) is used to analyse the variations in maize yield. A temporal assessment of the standardized yield residuals series (SYRS) of maize from 1961 to 2014 is conducted. A panel regression model is applied to demonstrate the drought impact on maize yield at various growth stages under the RCP4.5 scenario. The results show that the drought risk level for midwest Jilin Province, western Liaoning, and eastern Heilongjiang increase with global warming in the current scenario. The shorter three-dimensional joint return periods, 44-80 yr, were mainly located in western Jilin Province, Liaodong Peninsula, and northwestern Liaoning. Eastern Heilongjiang has a slightly longer joint return period of 80-100 yr. The SYRS shows a strong statistical correlation with drought indicator variations; drought-prone regions exhibit strong positive correlations. In comparison, excess precipitation regions show strong negative correlations with drought indicators in most growth stages. Drought indicators have a relatively strong association with SYRS at the milky-mature maize growth stage, and the occurrence of drought during this period primarily determines the maize yield changes in the future. Maize yield changes are -2.04%, -2.65% and -1.57% for Liaoning, Jilin, and

Coherent control of strong-field two-pulse ionization of Rydberg atoms.

PubMed

Fedorov, M; Poluektov, N

2000-02-28

Strong-field ionization of Rydberg atoms is investigated in its dependence on phase features of the initial coherent population of Rydberg levels. In the case of a resonance between Rydberg levels and some lower-energy atomic level (V-type transitions), this dependence is shown to be very strong: by a proper choice of the initial population an atom can be made either completely or very little ionized by a strong laser pulse. It is shown that phase features of the initial coherent population of Rydberg levels and the ionization yield can be efficiently controlled in a scheme of ionization by two strong laser pulses with a varying delay time between them.

Unity quantum yield of photogenerated charges and band-like transport in quantum-dot solids.

PubMed

Talgorn, Elise; Gao, Yunan; Aerts, Michiel; Kunneman, Lucas T; Schins, Juleon M; Savenije, T J; van Huis, Marijn A; van der Zant, Herre S J; Houtepen, Arjan J; Siebbeles, Laurens D A

2011-09-25

Solid films of colloidal quantum dots show promise in the manufacture of photodetectors and solar cells. These devices require high yields of photogenerated charges and high carrier mobilities, which are difficult to achieve in quantum-dot films owing to a strong electron-hole interaction and quantum confinement. Here, we show that the quantum yield of photogenerated charges in strongly coupled PbSe quantum-dot films is unity over a large temperature range. At high photoexcitation density, a transition takes place from hopping between localized states to band-like transport. These strongly coupled quantum-dot films have electrical properties that approach those of crystalline bulk semiconductors, while retaining the size tunability and cheap processing properties of colloidal quantum dots.

Communication: Strong laser alignment of solvent-solute aggregates in the gas-phase

NASA Astrophysics Data System (ADS)

Trippel, Sebastian; Wiese, Joss; Mullins, Terry; Küpper, Jochen

2018-03-01

Strong quasi-adiabatic laser alignment of the indole-water-dimer clusters, an amino-acid chromophore bound to a single water molecule through a hydrogen bond, was experimentally realized. The alignment was visualized through ion and electron imaging following strong-field ionization. Molecular-frame photoelectron angular distributions showed a clear suppression of the electron yield in the plane of the ionizing laser's polarization, which was analyzed as strong alignment of the molecular cluster with ⟨cos2 θ2D⟩ ≥ 0.9.

Strong monogamy conjecture in a four-qubit system

NASA Astrophysics Data System (ADS)

Karmakar, Sumana; Sen, Ajoy; Bhar, Amit; Sarkar, Debasis

2016-01-01

Monogamy is a defining feature of entanglement, having far-reaching applications. Recently, Regula et al. [Phys. Rev. Lett. 113, 110501 (2014), 10.1103/PhysRevLett.113.110501] proposed a stronger version of monogamy relation for concurrence. We have extended the strong monogamy inequality for another entanglement measure, viz., negativity. In particular, we have concentrated on the four-qubit system and provided a detailed study on the status of strong monogamy on pure states. Further, we have analytically provided some classes of states for which negativity and squared negativity satisfy strong monogamy. Numerical evidences have also been shown in proper places. Our analysis also provides cases where strong monogamy is violated.

Step edge sputtering yield at grazing incidence ion bombardment.

PubMed

Hansen, Henri; Polop, Celia; Michely, Thomas; Friedrich, Andreas; Urbassek, Herbert M

2004-06-18

The surface morphology of Pt(111) was investigated by scanning tunneling microscopy after 5 keV Ar+ ion bombardment at grazing incidence in dependence of the ion fluence and in the temperature range between 625 and 720 K. The average erosion rate was found to be strongly dependent on the ion fluence and the substrate temperature during bombardment. This dependence is traced back to the variation of step concentration with temperature and fluence. We develop a simple model allowing us to determine separately the constant sputtering yields for terraces and for impact area stripes in front of ascending steps. The experimentally determined yield of these stripes--the step-edge sputtering yield--is in excellent agreement with our molecular dynamics simulations performed for the experimental situation.

Ion kinetic dynamics in strongly-shocked plasmas relevant to ICF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rinderknecht, H. G.; Amendt, P. A.; Rosenberg, M. J.

Implosions of thin-shell capsules produce strongly-shocked (M > 10), low-density (ρ ~1 mg/cc -1), high-temperature (T i ~keV) plasmas, comparable to those produced in the strongly-shocked DT-vapor in inertial confinement fusion (ICF) experiments. A series of thin-glass targets filled with mixtures of deuterium and Helium-3 gas ranging from 7% to 100% deuterium was imploded to investigate the impact of multi-species ion kinetic mechanisms in ICF-relevant plasmas over a wide range of Knudsen numbers (N K ≡ λ ii/R). Anomalous trends in nuclear yields and burn-averaged ion temperatures in implosions with N K > 0.5, which have been interpreted as signaturesmore » of ion species separation and ion thermal decoupling, are found not to be consistent with single-species ion kinetic effects alone. Experimentally inferred Knudsen numbers predict an opposite yield trend to those observed, confirming the dominance of multi-species physics in these experiments. In contrast, implosions with N K ~ 0.01 follow the expected yield trend, suggesting single-species kinetic effects are dominant. In conclusion, the impact of the observed kinetic physics mechanisms on the formation of the hotspot in ICF experiments is discussed.« less

Ion kinetic dynamics in strongly-shocked plasmas relevant to ICF

DOE PAGES

Rinderknecht, H. G.; Amendt, P. A.; Rosenberg, M. J.; ...

2017-04-20

Implosions of thin-shell capsules produce strongly-shocked (M > 10), low-density (ρ ~1 mg/cc -1), high-temperature (T i ~keV) plasmas, comparable to those produced in the strongly-shocked DT-vapor in inertial confinement fusion (ICF) experiments. A series of thin-glass targets filled with mixtures of deuterium and Helium-3 gas ranging from 7% to 100% deuterium was imploded to investigate the impact of multi-species ion kinetic mechanisms in ICF-relevant plasmas over a wide range of Knudsen numbers (N K ≡ λ ii/R). Anomalous trends in nuclear yields and burn-averaged ion temperatures in implosions with N K > 0.5, which have been interpreted as signaturesmore » of ion species separation and ion thermal decoupling, are found not to be consistent with single-species ion kinetic effects alone. Experimentally inferred Knudsen numbers predict an opposite yield trend to those observed, confirming the dominance of multi-species physics in these experiments. In contrast, implosions with N K ~ 0.01 follow the expected yield trend, suggesting single-species kinetic effects are dominant. In conclusion, the impact of the observed kinetic physics mechanisms on the formation of the hotspot in ICF experiments is discussed.« less

Shock waves in strongly coupled plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khlebnikov, Sergei; Kruczenski, Martin; Michalogiorgakis, Georgios

2010-12-15

Shock waves are supersonic disturbances propagating in a fluid and giving rise to dissipation and drag. Weak shocks, i.e., those of small amplitude, can be well described within the hydrodynamic approximation. On the other hand, strong shocks are discontinuous within hydrodynamics and therefore probe the microscopics of the theory. In this paper, we consider the case of the strongly coupled N=4 plasma whose microscopic description, applicable for scales smaller than the inverse temperature, is given in terms of gravity in an asymptotically AdS{sub 5} space. In the gravity approximation, weak and strong shocks should be described by smooth metrics withmore » no discontinuities. For weak shocks, we find the dual metric in a derivative expansion, and for strong shocks we use linearized gravity to find the exponential tail that determines the width of the shock. In particular, we find that, when the velocity of the fluid relative to the shock approaches the speed of light v{yields}1 the penetration depth l scales as l{approx}(1-v{sup 2}){sup 1/4}. We compare the results with second-order hydrodynamics and the Israel-Stewart approximation. Although they all agree in the hydrodynamic regime of weak shocks, we show that there is not even qualitative agreement for strong shocks. For the gravity side, the existence of shock waves implies that there are disturbances of constant shape propagating on the horizon of the dual black holes.« less

Field evidence of strong differential pollen placement by Old World bat-pollinated plants

PubMed Central

Stewart, Alyssa B.; Dudash, Michele R.

2017-01-01

Background and Aims Sympatric plant species that share pollinators potentially compete for pollination and risk interspecific pollen transfer, but this competition can be minimized when plant species place pollen on different areas of the pollinator’s body. Multiple studies have demonstrated strong differential pollen placement by sympatric plant species under laboratory conditions; however, field evidence collected in natural settings is less common. Furthermore, it is unknown whether precise pollen placement on the pollinator’s body remains constant throughout the foraging period, or if such patterns become diffused over time (e.g. due to grooming). To test the prevalence of differential pollen placement in the wild, we examined a community of five night-blooming plant species in southern Thailand that share common bat pollinators. Methods We mist-netted wild foraging nectar bats and collected pollen samples from four body parts: the crown of the head, face, chest and ventral side of one wing. We also noted the time of pollen collection to assess how pollinator pollen loads change throughout the foraging period. Key Results Our findings revealed that most of our plant study species placed pollen on precise areas of the bat, consistent with experimental work, and that patterns of differential pollen placement remained constant throughout the night. Conclusions This study demonstrates how diverse floral morphologies effectively limit interspecific pollen transfer among Old World bat-pollinated plants under natural conditions. Additionally, interspecific pollen transfer is probably minimal throughout the entire foraging period, since patterns of pollen on the bats’ bodies were consistent over time. PMID:27864223

High Useful Yield and Isotopic Analysis of Uranium by Resonance Ionization Mass Spectrometry

DOE PAGES

Savina, Michael R.; Isselhardt, Brett H.; Kucher, Andrew; ...

2017-05-09

Useful yields from resonance ionization mass spectrometry can be extremely high compared to other mass spectrometry techniques, but uranium analysis shows strong matrix effects arising from the tendency of uranium to form strongly bound oxide molecules that do not dissociate appreciably on energetic ion bombardment. Here, we demonstrate a useful yield of 24% for metallic uranium. Modeling the laser ionization and ion transmission processes shows that the high useful yield is attributable to a high ion fraction achieved by resonance ionization. We quantify the reduction of uranium oxide surface layers by Ar + and Ga + sputtering. The useful yieldmore » for uranium atoms from a uranium dioxide matrix is 0.4% and rises to 2% when the surface is in sputter equilibrium with the ion beam. The lower useful yield from the oxide is almost entirely due to uranium oxide molecules reducing the neutral atom content of the sputtered flux. We also demonstrate rapid isotopic analysis of solid uranium oxide at a precision of <0.5% relative standard deviation using relatively broadband lasers to mitigate spectroscopic fractionation.« less

High Useful Yield and Isotopic Analysis of Uranium by Resonance Ionization Mass Spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Savina, Michael R.; Isselhardt, Brett H.; Kucher, Andrew

Useful yields from resonance ionization mass spectrometry can be extremely high compared to other mass spectrometry techniques, but uranium analysis shows strong matrix effects arising from the tendency of uranium to form strongly bound oxide molecules that do not dissociate appreciably on energetic ion bombardment. Here, we demonstrate a useful yield of 24% for metallic uranium. Modeling the laser ionization and ion transmission processes shows that the high useful yield is attributable to a high ion fraction achieved by resonance ionization. We quantify the reduction of uranium oxide surface layers by Ar + and Ga + sputtering. The useful yieldmore » for uranium atoms from a uranium dioxide matrix is 0.4% and rises to 2% when the surface is in sputter equilibrium with the ion beam. The lower useful yield from the oxide is almost entirely due to uranium oxide molecules reducing the neutral atom content of the sputtered flux. We also demonstrate rapid isotopic analysis of solid uranium oxide at a precision of <0.5% relative standard deviation using relatively broadband lasers to mitigate spectroscopic fractionation.« less

Spatial relationships among cereal yields and selected soil physical and chemical properties.

PubMed

Lipiec, Jerzy; Usowicz, Bogusław

2018-08-15

Sandy soils occupy large area in Poland (about 50%) and in the world. This study aimed at determining spatial relationships of cereal yields and the selected soil physical and chemical properties in three study years (2001-2003) on low productive sandy Podzol soil (Podlasie, Poland). The yields and soil properties in plough and subsoil layers were determined at 72-150 points. The test crops were: wheat, wheat and barley mixture and oats. To explore the spatial relationship between cereal yields and each soil property spatial statistics was used. The best fitting models were adjusted to empirical semivariance and cross-semivariance, which were used to draw maps using kriging. Majority of the soil properties and crop yields exhibited low and medium variability (coefficient of variation 5-70%). The effective ranges of the spatial dependence (the distance at which data are autocorrelated) for yields and all soil properties were 24.3-58.5m and 10.5-373m, respectively. Nugget to sill ratios showed that crop yields and soil properties were strongly spatially dependent except bulk density. Majority of the pairs in cross-semivariograms exhibited strong spatial interdependence. The ranges of the spatial dependence varied in plough layer between 54.6m for yield×pH up to 2433m for yield×silt content. Corresponding ranges in subsoil were 24.8m for crop yield×clay content in 2003 and 1404m for yield×bulk density. Kriging maps allowed separating sub-field area with the lowest yield and soil cation exchange capacity, organic carbon content and pH. This area had lighter color on the aerial photograph due to high content of the sand and low content of soil organic carbon. The results will help farmers at identifying sub-field areas for applying localized management practices to improve these soil properties and further spatial studies in larger scale. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

African crop yield reductions due to increasingly unbalanced Nitrogen and Phosphorus consumption

NASA Astrophysics Data System (ADS)

van der Velde, Marijn; Folberth, Christian; Balkovič, Juraj; Ciais, Philippe; Fritz, Steffen; Janssens, Ivan A.; Obersteiner, Michael; See, Linda; Skalský, Rastislav; Xiong, Wei; Peñuealas, Josep

2014-05-01

The impact of soil nutrient depletion on crop production has been known for decades, but robust assessments of the impact of increasingly unbalanced nitrogen (N) and phosphorus (P) application rates on crop production are lacking. Here, we use crop response functions based on 741 FAO maize crop trials and EPIC crop modeling across Africa to examine maize yield deficits resulting from unbalanced N:P applications under low, medium, and high input scenarios, for past (1975), current, and future N:P mass ratios of respectively, 1:0.29, 1:0.15, and 1:0.05. At low N inputs (10 kg/ha), current yield deficits amount to 10% but will increase up to 27% under the assumed future N:P ratio, while at medium N inputs (50 kg N/ha), future yield losses could amount to over 40%. The EPIC crop model was then used to simulate maize yields across Africa. The model results showed relative median future yield reductions at low N inputs of 40%, and 50% at medium and high inputs, albeit with large spatial variability. Dominant low-quality soils such as Ferralsols, which are strongly adsorbing P, and Arenosols with a low nutrient retention capacity, are associated with a strong yield decline, although Arenosols show very variable crop yield losses at low inputs. Optimal N:P ratios, i.e. those where the lowest amount of applied P produces the highest yield (given N input) where calculated with EPIC to be as low as 1:0.5. Finally, we estimated the additional P required given current N inputs, and given N inputs that would allow Africa to close yield gaps (ca. 70%). At current N inputs, P consumption would have to increase 2.3-fold to be optimal, and to increase 11.7-fold to close yield gaps. The P demand to overcome these yield deficits would provide a significant additional pressure on current global extraction of P resources.

Secondary electron emission yield from high aspect ratio carbon velvet surfaces

DOE PAGES

Jin, Chenggang; Ottaviano, Angelica; Raitses, Yevgeny

2017-11-01

The plasma electrons bombarding a plasma-facing wall surface can induce secondary electron emission (SEE) from the wall. A strong SEE can enhance the power losses by reducing the wall sheath potential and thereby increasing the electron flux from the plasma to the wall. The use of the materials with surface roughness and the engineered materials with surface architecture is known to reduce the effective SEE by trapping the secondary electrons. In this work, we demonstrate a 65% reduction of SEE yield using a velvet material consisting of high aspect ratio carbon fibers. The measurements of SEE yield for different velvetmore » samples using the electron beam in vacuum demonstrate the dependence of the SEE yield on the fiber length and the packing density, which is strongly affected by the alignment of long velvet fibers with respect to the electron beam impinging on the velvet sample. Furthermore, the results of SEE measurements support the previous observations of the reduced SEE measured in Hall thrusters.« less

Strong Stackelberg reasoning in symmetric games: An experimental replication and extension

PubMed Central

Colman, Andrew M.; Lawrence, Catherine L.

2014-01-01

In common interest games in which players are motivated to coordinate their strategies to achieve a jointly optimal outcome, orthodox game theory provides no general reason or justification for choosing the required strategies. In the simplest cases, where the optimal strategies are intuitively obvious, human decision makers generally coordinate without difficulty, but how they achieve this is poorly understood. Most theories seeking to explain strategic coordination have limited applicability, or require changes to the game specification, or introduce implausible assumptions or radical departures from fundamental game-theoretic assumptions. The theory of strong Stackelberg reasoning, according to which players choose strategies that would maximize their own payoffs if their co-players could invariably anticipate any strategy and respond with a best reply to it, avoids these problems and explains strategic coordination in all dyadic common interest games. Previous experimental evidence has provided evidence for strong Stackelberg reasoning in asymmetric games. Here we report evidence from two experiments consistent with players being influenced by strong Stackelberg reasoning in a wide variety of symmetric 3 × 3 games but tending to revert to other choice criteria when strong Stackelberg reasoning generates small payoffs. PMID:24688846

Strong Stackelberg reasoning in symmetric games: An experimental replication and extension.

PubMed

Pulford, Briony D; Colman, Andrew M; Lawrence, Catherine L

2014-01-01

In common interest games in which players are motivated to coordinate their strategies to achieve a jointly optimal outcome, orthodox game theory provides no general reason or justification for choosing the required strategies. In the simplest cases, where the optimal strategies are intuitively obvious, human decision makers generally coordinate without difficulty, but how they achieve this is poorly understood. Most theories seeking to explain strategic coordination have limited applicability, or require changes to the game specification, or introduce implausible assumptions or radical departures from fundamental game-theoretic assumptions. The theory of strong Stackelberg reasoning, according to which players choose strategies that would maximize their own payoffs if their co-players could invariably anticipate any strategy and respond with a best reply to it, avoids these problems and explains strategic coordination in all dyadic common interest games. Previous experimental evidence has provided evidence for strong Stackelberg reasoning in asymmetric games. Here we report evidence from two experiments consistent with players being influenced by strong Stackelberg reasoning in a wide variety of symmetric 3 × 3 games but tending to revert to other choice criteria when strong Stackelberg reasoning generates small payoffs.

Managing Southeastern US Forests for Increased Water Yield

NASA Astrophysics Data System (ADS)

Acharya, S.; Kaplan, D. A.; Mclaughlin, D. L.; Cohen, M. J.

2017-12-01

Forested lands influence watershed hydrology by affecting water quantity and quality in surface and groundwater systems, making them potentially effective tools for regional water resource planning. In this study, we quantified water use and water yield by pine forests under varying silvicultural management (e.g., high density plantation, thinning, and prescribed burning). Daily forest water use (evapotranspiration, ET) was estimated using continuously monitored soil-moisture in the root-zone at six sites across Florida (USA), each with six plots ranging in forest leaf-area index (LAI). Plots included stands with different rotational ages (from clear-cut to mature pine plantations) and those restored to more historical conditions. Estimated ET relative to potential ET (PET) was strongly associated with LAI, root-zone soil-moisture status, and site hydroclimate; these factors explained 85% of the variation in the ET:PET ratio. Annual water yield (Yw) calculated from these ET estimates and a simple water balance differed significantly among sites and plots (ranging from -0.12 cm/yr to > 100 cm/yr), demonstrating substantive influence of management regimes. LAI strongly influenced Yw in all sites, and a general linear model with forest attributes (LAI and groundcover), hydroclimate, and site characteristics explained >90% of variation in observed Yw. These results can be used to predict water yield changes under different management and climate scenarios and may be useful in the development of payment for ecosystem services approaches that identify water as an important product of forest best management practices.

Large electroweak penguin contribution in B{yields}K{pi} and {pi}{pi} decay modes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mishima, Satoshi; Yoshikawa, Tadashi

2004-11-01

We discuss a possibility of large electroweak penguin contribution in B{yields}K{pi} and {pi}{pi} from recent experimental data. The experimental data may be suggesting that there are some discrepancies between the data and theoretical estimation in the branching ratios of them. In B{yields}K{pi} decays, to explain it, a large electroweak penguin contribution and large strong phase differences seem to be needed. The contributions should appear also in B{yields}{pi}{pi}. We show, as an example, a solution to solve the discrepancies in both B{yields}K{pi} and B{yields}{pi}{pi}. However the magnitude of the parameters and the strong phase estimated from experimental data are quite largemore » compared with the theoretical estimations. It may be suggesting some new physics effects are included in these processes. We will have to discuss about the dependence of the new physics. To explain both modes at once, we may need large electroweak penguin contribution with new weak phases and some SU(3) breaking effects by new physics in both QCD and electroweak penguin-type processes.« less

Evidence for a weakening strength of temperature-corn yield relation in the United States during 1980-2010.

PubMed

Leng, Guoyong

2017-12-15

Temperature is known to be correlated with crop yields, causing reduction of crop yield with climate warming without adaptations or CO 2 fertilization effects. The historical temperature-crop yield relation has often been used for informing future changes. This relationship, however, may change over time following alternations in other environmental factors. Results show that the strength of the relationship between the interannual variability of growing season temperature and corn yield (R GST_CY ) has declined in the United States between 1980 and 2010 with a loss in the statistical significance. The regression slope which represents the anomalies in corn yield that occur in association with 1 degree temperature anomaly has decreased significantly from -6.9%/K of the first half period to -2.4%/K--3.5%/K of the second half period. This implies that projected corn yield reduction will be overestimated by a fact of 2 in a given warming scenario, if the corn-temperature relation is derived from the earlier historical period. Changes in R GST_CY are mainly observed in Midwest Corn Belt and central High Plains, but are partly reproduced by 11 process-based crop models. In Midwest rain-fed systems, the decrease of negative temperature effects coincides with an increase in water availability by precipitation. In irrigated areas where water stress is minimized, the decline of beneficial temperature effects is significantly related to the increase in extreme hot days. The results indicate that an extrapolation of historical yield response to temperature may bias the assessment of agriculture vulnerability to climate change. Efforts to reduce climate impacts on agriculture should pay attention not only to climate change, but also to changes in climate-crop yield relations. There are some caveats that should be acknowledged as the analysis is restricted to the changes in the linear relation between growing season mean temperature and corn yield for the specific study period

Emergency department triage scales and their components: a systematic review of the scientific evidence.

PubMed

Farrohknia, Nasim; Castrén, Maaret; Ehrenberg, Anna; Lind, Lars; Oredsson, Sven; Jonsson, Håkan; Asplund, Kjell; Göransson, Katarina E

2011-06-30

Emergency department (ED) triage is used to identify patients' level of urgency and treat them based on their triage level. The global advancement of triage scales in the past two decades has generated considerable research on the validity and reliability of these scales. This systematic review aims to investigate the scientific evidence for published ED triage scales. The following questions are addressed: 1. Does assessment of individual vital signs or chief complaints affect mortality during the hospital stay or within 30 days after arrival at the ED?2. What is the level of agreement between clinicians' triage decisions compared to each other or to a gold standard for each scale (reliability)? 3. How valid is each triage scale in predicting hospitalization and hospital mortality? A systematic search of the international literature published from 1966 through March 31, 2009 explored the British Nursing Index, Business Source Premier, CINAHL, Cochrane Library, EMBASE, and PubMed. Inclusion was limited to controlled studies of adult patients (≥ 15 years) visiting EDs for somatic reasons. Outcome variables were death in ED or hospital and need for hospitalization (validity). Methodological quality and clinical relevance of each study were rated as high, medium, or low. The results from the studies that met the inclusion criteria and quality standards were synthesized applying the internationally developed GRADE system. Each conclusion was then assessed as having strong, moderately strong, limited, or insufficient scientific evidence. If studies were not available, this was also noted.We found ED triage scales to be supported, at best, by limited and often insufficient evidence.The ability of the individual vital signs included in the different scales to predict outcome is seldom, if at all, studied in the ED setting. The scientific evidence to assess interrater agreement (reliability) was limited for one triage scale and insufficient or lacking for all other

Emergency Department Triage Scales and Their Components: A Systematic Review of the Scientific Evidence

PubMed Central

2011-01-01

Emergency department (ED) triage is used to identify patients' level of urgency and treat them based on their triage level. The global advancement of triage scales in the past two decades has generated considerable research on the validity and reliability of these scales. This systematic review aims to investigate the scientific evidence for published ED triage scales. The following questions are addressed: 1. Does assessment of individual vital signs or chief complaints affect mortality during the hospital stay or within 30 days after arrival at the ED? 2. What is the level of agreement between clinicians' triage decisions compared to each other or to a gold standard for each scale (reliability)? 3. How valid is each triage scale in predicting hospitalization and hospital mortality? A systematic search of the international literature published from 1966 through March 31, 2009 explored the British Nursing Index, Business Source Premier, CINAHL, Cochrane Library, EMBASE, and PubMed. Inclusion was limited to controlled studies of adult patients (≥15 years) visiting EDs for somatic reasons. Outcome variables were death in ED or hospital and need for hospitalization (validity). Methodological quality and clinical relevance of each study were rated as high, medium, or low. The results from the studies that met the inclusion criteria and quality standards were synthesized applying the internationally developed GRADE system. Each conclusion was then assessed as having strong, moderately strong, limited, or insufficient scientific evidence. If studies were not available, this was also noted. We found ED triage scales to be supported, at best, by limited and often insufficient evidence. The ability of the individual vital signs included in the different scales to predict outcome is seldom, if at all, studied in the ED setting. The scientific evidence to assess interrater agreement (reliability) was limited for one triage scale and insufficient or lacking for all other

Synergistic effect in carbon coated LiFePO4 for high yield spontaneous grafting of diazonium salt. Structural examination at the grain agglomerate scale.

PubMed

Madec, Lénaïc; Robert, Donatien; Moreau, Philippe; Bayle-Guillemaud, Pascale; Guyomard, Dominique; Gaubicher, Joël

2013-08-07

Molecular grafting of p-nitrobenzene diazonium salt at the surface of (Li)FePO4-based materials was thoroughly investigated. The grafting yields obtained by FTIR, XPS, and elemental analysis for core shell LiFePO4-C are found to be much higher than the sum of those associated with either the LiFePO4 core or the carbon shell alone, thereby revealing a synergistic effect. Electrochemical, XRD, and EELS experiments demonstrate that this effect stems from the strong participation of the LiFePO4 core that delivers large amounts of electrons to the carbon substrate at a constant energy, above the Fermi level of the diazonium salt. Correspondingly large multilayer anisotropic structures that are associated with outstanding grafting yields could be observed from TEM experiments. Results therefore constitute strong evidence of a grafting mechanism where homolytic cleavage of the N2(+) species occurs together with the formation and grafting of radical nitro-aryl intermediates. Although the oxidation and concomitant Li deintercalation of LiFePO4 grains constitute the main driving force of the functionalization reaction, EFTEM EELS mapping shows a striking lack of spatial correlation between grafted grains and oxidized ones.

Brazilian Soybean Yields and Yield Gaps Vary with Farm Size

NASA Astrophysics Data System (ADS)

Jeffries, G. R.; Cohn, A.; Griffin, T. S.; Bragança, A.

2017-12-01

Understanding the farm size-specific characteristics of crop yields and yield gaps may help to improve yields by enabling better targeting of technical assistance and agricultural development programs. Linking remote sensing-based yield estimates with property boundaries provides a novel view of the relationship between farm size and yield structure (yield magnitude, gaps, and stability over time). A growing literature documents variations in yield gaps, but largely ignores the role of farm size as a factor shaping yield structure. Research on the inverse farm size-productivity relationship (IR) theory - that small farms are more productive than large ones all else equal - has documented that yield magnitude may vary by farm size, but has not considered other yield structure characteristics. We examined farm size - yield structure relationships for soybeans in Brazil for years 2001-2015. Using out-of-sample soybean yield predictions from a statistical model, we documented 1) gaps between the 95th percentile of attained yields and mean yields within counties and individual fields, and 2) yield stability defined as the standard deviation of time-detrended yields at given locations. We found a direct relationship between soy yields and farm size at the national level, while the strength and the sign of the relationship varied by region. Soybean yield gaps were found to be inversely related to farm size metrics, even when yields were only compared to farms of similar size. The relationship between farm size and yield stability was nonlinear, with mid-sized farms having the most stable yields. The work suggests that farm size is an important factor in understanding yield structure and that opportunities for improving soy yields in Brazil are greatest among smaller farms.

Field evidence of strong differential pollen placement by Old World bat-pollinated plants.

PubMed

Stewart, Alyssa B; Dudash, Michele R

2017-01-01

Sympatric plant species that share pollinators potentially compete for pollination and risk interspecific pollen transfer, but this competition can be minimized when plant species place pollen on different areas of the pollinator's body. Multiple studies have demonstrated strong differential pollen placement by sympatric plant species under laboratory conditions; however, field evidence collected in natural settings is less common. Furthermore, it is unknown whether precise pollen placement on the pollinator's body remains constant throughout the foraging period, or if such patterns become diffused over time (e.g. due to grooming). To test the prevalence of differential pollen placement in the wild, we examined a community of five night-blooming plant species in southern Thailand that share common bat pollinators. We mist-netted wild foraging nectar bats and collected pollen samples from four body parts: the crown of the head, face, chest and ventral side of one wing. We also noted the time of pollen collection to assess how pollinator pollen loads change throughout the foraging period. Our findings revealed that most of our plant study species placed pollen on precise areas of the bat, consistent with experimental work, and that patterns of differential pollen placement remained constant throughout the night. This study demonstrates how diverse floral morphologies effectively limit interspecific pollen transfer among Old World bat-pollinated plants under natural conditions. Additionally, interspecific pollen transfer is probably minimal throughout the entire foraging period, since patterns of pollen on the bats' bodies were consistent over time. © 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.

Making biodiversity-friendly cocoa pay: combining yield, certification, and REDD for shade management.

PubMed

Waldron, A; Justicia, R; Smith, L E

2015-03-01

The twin United Nations' Millennium Development Goals of biodiversity preservation and poverty reduction both strongly depend on actions in the tropics. In particular, traditional agroforestry could be critical to both biological conservation and human livelihoods in human-altered rainforest areas. However, traditional agroforestry is rapidly disappearing, because the system itself is economically precarious, and because the forest trees that shade traditional crops are now perceived to be overly detrimental to agricultural yield. Here, we show a case where the commonly used agroforestry shade metric, canopy cover, would indeed suggest complete removal of shade trees to maximize yield, with strongly negative biodiversity and climate implications. However, a yield over 50% higher was achievable if approximately 100 shade trees per hectare were planted in a spatially organized fashion, a win-win for biodiversity and the smallholder. The higher yield option was detected by optimizing simultaneously for canopy cover, and a second shade metric, neighboring tree density, which was designed to better capture the yield value of ecological services flowing from forest trees. Nevertheless, even a 50% yield increase may prove insufficient to stop farmers converting away from traditional agroforestry. To further increase agroforestry rents, we apply our results to the design of a sustainable certification (eco-labelling) scheme for cocoa-based products in a biodiversity hotspot, and consider their implications for the use of the United Nations REDD (reducing emissions from deforestation and forest degradation) program in agroforestry systems. Combining yield boost, certification, and REDD has the potential to incentivize eco-friendly agroforestry and lift smallholders out of poverty, simultaneously.

Atomistic basis for the plastic yield criterion of metallic glass.

PubMed

Schuh, Christopher A; Lund, Alan C

2003-07-01

Because of their disordered atomic structure, amorphous metals (termed metallic glasses) have fundamentally different deformation mechanisms compared with polycrystalline metals. These different mechanisms give metallic glasses high strength, but the extent to which they affect other macroscopic deformation properties is uncertain. For example, the nature of the plastic-yield criterion is a point of contention, with some studies reporting yield behaviour roughly in line with that of polycrystalline metals, and others indicating strong fundamental differences. In particular, it is unclear whether pressure- or normal stress-dependence needs to be included in the plastic-yield criterion of metallic glasses, and how such a dependence could arise from their disordered structure. In this work we provide an atomic-level explanation for pressure-dependent yield in amorphous metals, based on an elementary unit of deformation. This simple model compares favourably with new atomistic simulations of metallic glasses, as well as existing experimental data.

Crop Diversity for Yield Increase

PubMed Central

Li, Chengyun; He, Xiahong; Zhu, Shusheng; Zhou, Huiping; Wang, Yunyue; Li, Yan; Yang, Jing; Fan, Jinxiang; Yang, Jincheng; Wang, Guibin; Long, Yunfu; Xu, Jiayou; Tang, Yongsheng; Zhao, Gaohui; Yang, Jianrong; Liu, Lin; Sun, Yan; Xie, Yong; Wang, Haining; Zhu, Youyong

2009-01-01

Traditional farming practices suggest that cultivation of a mixture of crop species in the same field through temporal and spatial management may be advantageous in boosting yields and preventing disease, but evidence from large-scale field testing is limited. Increasing crop diversity through intercropping addresses the problem of increasing land utilization and crop productivity. In collaboration with farmers and extension personnel, we tested intercropping of tobacco, maize, sugarcane, potato, wheat and broad bean – either by relay cropping or by mixing crop species based on differences in their heights, and practiced these patterns on 15,302 hectares in ten counties in Yunnan Province, China. The results of observation plots within these areas showed that some combinations increased crop yields for the same season between 33.2 and 84.7% and reached a land equivalent ratio (LER) of between 1.31 and 1.84. This approach can be easily applied in developing countries, which is crucial in face of dwindling arable land and increasing food demand. PMID:19956624

Quenched bond randomness: Superfluidity in porous media and the strong violation of universality

NASA Astrophysics Data System (ADS)

Falicov, Alexis; Berker, A. Nihat

1997-04-01

The effects of quenched bond randomness are most readily studied with superfluidity immersed in a porous medium. A lattice model for3He-4He mixtures and incomplete4He fillings in aerogel yields the signature effect of bond randomness, namely the conversion of symmetry-breaking first-order phase transitions into second-order phase transitions, the λ-line reaching zero temperature, and the elimination of non-symmetry-breaking first-order phase transitions. The model recognizes the importance of the connected nature of aerogel randomness and thereby yields superfluidity at very low4He concentrations, a phase separation entirely within the superfluid phase, and the order-parameter contrast between mixtures and incomplete fillings, all in agreement with experiments. The special properties of the helium mixture/aerogel system are distinctly linked to the aerogel properties of connectivity, randomness, and tenuousness, via the additional study of a regularized “jungle-gym” aerogel. Renormalization-group calculations indicate that a strong violation of the empirical universality principle of critical phenomena occurs under quenched bond randomness. It is argued that helium/aerogel critical properties reflect this violation and further experiments are suggested. Renormalization-group analysis also shows that, adjoiningly to the strong universality violation (which hinges on the occurrence or non-occurrence of asymptotic strong coupling—strong randomness under rescaling), there is a new “hyperuniversality” at phase transitions with asymptotic strong coupling—strong randomness behavior, for example assigning the same critical exponents to random- bond tricriticality and random- field criticality.

Climate Change Impact on Rainfall: How will Threaten Wheat Yield?

NASA Astrophysics Data System (ADS)

Tafoughalti, K.; El Faleh, E. M.; Moujahid, Y.; Ouargaga, F.

2018-05-01

Climate change has a significant impact on the environmental condition of the agricultural region. Meknes has an agrarian economy and wheat production is of paramount importance. As most arable area are under rainfed system, Meknes is one of the sensitive regions to rainfall variability and consequently to climate change. Therefore, the use of changes in rainfall is vital for detecting the influence of climate system on agricultural productivity. This article identifies rainfall temporal variability and its impact on wheat yields. We used monthly rainfall records for three decades and wheat yields records of fifteen years. Rainfall variability is assessed utilizing the precipitation concentration index and the variation coefficient. The association between wheat yields and cumulative rainfall amounts of different scales was calculated based on a regression model. The analysis shown moderate seasonal and irregular annual rainfall distribution. Yields fluctuated from 210 to 4500 Kg/ha with 52% of coefficient of variation. The correlation results shows that wheat yields are strongly correlated with rainfall of the period January to March. This investigation concluded that climate change is altering wheat yield and it is crucial to adept the necessary adaptation to challenge the risk.

UpToDate adherence to GRADE criteria for strong recommendations: an analytical survey

PubMed Central

Merglen, Arnaud; Heen, Anja Fog; Kristiansen, Annette; Neumann, Ignacio; Brito, Juan P; Brignardello-Petersen, Romina; Alexander, Paul E; Rind, David M; Vandvik, Per O; Guyatt, Gordon H

2017-01-01

Introduction UpToDate is widely used by clinicians worldwide and includes more than 9400 recommendations that apply the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework. GRADE guidance warns against strong recommendations when certainty of the evidence is low or very low (discordant recommendations) but has identified five paradigmatic situations in which discordant recommendations may be justified. Objectives Our objective was to document the strength of recommendations in UpToDate and assess the frequency and appropriateness of discordant recommendations. Design Analytical survey of all recommendations in UpToDate. Methods We identified all GRADE recommendations in UpToDate and examined their strength (strong or weak) and certainty of the evidence (high, moderate or low certainty). We identified all discordant recommendations as of January 2015, and pairs of reviewers independently classified them either into one of the five appropriate paradigms or into one of three categories inconsistent with GRADE guidance, based on the evidence presented in UpToDate. Results UpToDate included 9451 GRADE recommendations, of which 6501 (68.8%) were formulated as weak recommendations and 2950 (31.2%) as strong. Among the strong, 844 (28.6%) were based on high certainty in effect estimates, 1740 (59.0%) on moderate certainty and 366 (12.4%) on low certainty. Of the 349 discordant recommendations 204 (58.5%) were judged appropriately (consistent with one of the five paradigms); we classified 47 (13.5%) as good practice statements; 38 (10.9%) misclassified the evidence as low certainty when it was at least moderate and 60 (17.2%) warranted a weak rather than a strong recommendation. Conclusion The proportion of discordant recommendations in UpToDate is small (3.7% of all recommendations) and the proportion that is truly problematic (strong recommendations that would best have been weak) is very small (0.6%). Clinicians should nevertheless be

Climate Variability and Yields of Major Staple Food Crops in Northern Ghana

NASA Astrophysics Data System (ADS)

Amikuzuno, J.

2012-12-01

Climate variability, the short-term fluctuations in average weather conditions, and agriculture affect each other. Climate variability affects the agroecological and growing conditions of crops and livestock, and is recently believed to be the greatest impediment to the realisation of the first Millennium Development Goal of reducing poverty and food insecurity in arid and semi-arid regions of developing countries. Conversely, agriculture is a major contributor to climate variability and change by emitting greenhouse gases and reducing the agroecology's potential for carbon sequestration. What however, is the empirical evidence of this inter-dependence of climate variability and agriculture in Sub-Sahara Africa? In this paper, we provide some insight into the long run relationship between inter-annual variations in temperature and rainfall, and annual yields of the most important staple food crops in Northern Ghana. Applying pooled panel data of rainfall, temperature and yields of the selected crops from 1976 to 2010 to cointegration and Granger causality models, there is cogent evidence of cointegration between seasonal, total rainfall and crop yields; and causality from rainfall to crop yields in the Sudano-Guinea Savannah and Guinea Savannah zones of Northern Ghana. This suggests that inter-annual yields of the crops have been influenced by the total mounts of rainfall in the planting season. Temperature variability over the study period is however stationary, and is suspected to have minimal effect if any on crop yields. Overall, the results confirm the appropriateness of our attempt in modelling long-term relationships between the climate and crop yield variables.

Instrumental evidence of an unusually strong West African Monsoon in the 19th century

NASA Astrophysics Data System (ADS)

Gallego, David; Ordoñez, Paulina; Ribera, Pedro; Peña-Ortiz, Cristina; Garcia-Herrera, Ricardo; Vega, Inmaculada; Gomez, Francisco de Paula

2016-04-01

The precipitation in the Sahel -which is mainly controlled by the dynamics of the West African Monsoon-, has been in the spot of the climate community for the last three decades due to the persistence of the drought period that started in the 1970s. Unfortunately, reliable meteorological series in this area are only available since the beginning of the 20th Century, thus limiting our understanding of the significance of this period from a long term perspective. Currently, our knowledge of what happened in times previous to the 20th Century essentially relies in documentary or proxy sources. In this work, we present the first instrumental evidence of a 50 year-long period characterised by an unusually strong West African monsoon in the19th Century. Following the recent advances in the generation of climatic indices based on data from ship's logbooks, we used historical wind observations to compute a new index (the so-called ASWI) for characterising the strength of the West African Monsoon. The ASWI is based in the persistence of the southwesterly winds in the [29°W-17°W;7°N-13°N] area and it has been possible to compute it since 1790 for July and since 1839 for August and September. We show that the ASWI is a reliable measure of the monsoon's strength and the Sahelian rainfall. Our new series clearly shows the well-known drought period starting in the 1970s. During this dry period, the West African Monsoon was particularly weak and interestingly, we found that since then, the correlations with different climatic patterns such as the Pacific and Atlantic "El Niño" changed significantly in relation to those of the previous century. Remarkably, our results also show that the period 1839-1890 was characterised by an unusually strong and persistent monsoon. Notwithstanding, two of the few dry years within this period were concurrent with large volcanic eruptions in the Northern Hemisphere. This latter result supports the recently suggested relationship between major

Starting Strong: Feasibility of an Indicated Prevention Programme during the Transition to Kindergarten

ERIC Educational Resources Information Center

Eisenhower, Abbey; Baker, Bruce L.; Taylor, Heather

2016-01-01

School-based mental health services are a promising context for evidence-based interventions to promote early socio-emotional development, yet implementation presents significant challenges. This paper describes the rationale, content and format of a school-based intervention, Starting Strong in Kindergarten (Starting Strong). Starting Strong is a…

The Empirical Evidence for the Telemedicine Intervention in Diabetes Management

PubMed Central

Shannon, Gary W.; Smith, Brian R.; Woodward, Maria A.

2015-01-01

Abstract Objective: The research presented here assesses the scientific evidence for the telemedicine intervention in the management of diabetes (telediabetes), gestational diabetes, and diabetic retinopathy. The impetus derives from the confluence of high prevalence of these diseases, increasing incidence, and rising costs, while telemedicine promises to ameliorate, if not prevent, type 2 diabetes and its complications. Materials and Methods: A purposeful review of the literature identified relevant publications from January 2005 to December 2013. These were culled to retain only credible research articles for detailed review and analysis. The search yielded approximately 17,000 articles with no date constraints. Of these, 770 appeared to be research articles within our time frame. A review of the abstracts yielded 73 articles that met the criteria for inclusion in the final analysis. Evidence is organized by research findings regarding feasibility/acceptance, intermediate outcomes (e.g., use of service, and screening compliance), and health outcomes (control of glycemic level, lipids, body weight, and physical activity.) Results: Definitions of telediabetes varied from study to study vis-à-vis diabetes subtype, setting, technology, staffing, duration, frequency, and target population. Outcome measures also varied. Despite these vagaries, sufficient evidence was obtained from a wide variety of research studies, consistently pointing to positive effects of telemonitoring and telescreening in terms of glycemic control, reduced body weight, and increased physical exercise. The major contributions point to telemedicine's potential for changing behaviors important to diabetes control and prevention, especially type 2 and gestational diabetes. Similarly, screening and monitoring for retinopathy can detect symptoms early that may be controlled or treated. Conclusions: Overall, there is strong and consistent evidence of improved glycemic control among persons with type 2

Tree growth and management in Ugandan agroforestry systems: effects of root pruning on tree growth and crop yield.

PubMed

Wajja-Musukwe, Tellie-Nelson; Wilson, Julia; Sprent, Janet I; Ong, Chin K; Deans, J Douglas; Okorio, John

2008-02-01

Tree root pruning is a potential tool for managing belowground competition when trees and crops are grown together in agroforestry systems. We investigated the effects of tree root pruning on shoot growth and root distribution of Alnus acuminata (H.B. & K.), Casuarina equisetifolia L., Grevillea robusta A. Cunn. ex R. Br., Maesopsis eminii Engl. and Markhamia lutea (Benth.) K. Schum. and on yield of adjacent crops in sub-humid Uganda. The trees were 3 years old at the commencement of the study, and most species were competing strongly with crops. Tree roots were pruned 41 months after planting by cutting and back-filling a trench to a depth of 0.3 m, at a distance of 0.3 m from the trees, on one side of the tree row. The trench was reopened and roots recut at 50 and 62 months after planting. We assessed the effects on tree growth and root distribution over a 3 year period, and crop yield after the third root pruning at 62 months. Overall, root pruning had only a slight effect on aboveground tree growth: height growth was unaffected and diameter growth was reduced by only 4%. A substantial amount of root regrowth was observed by 11 months after pruning. Tree species varied in the number and distribution of roots, and C. equisetifolia and M. lutea had considerably more roots per unit of trunk volume than the other species, especially in the surface soil layers. Casuarina equisetifolia and M. eminii were the tree species most competitive with crops and G. robusta and M. lutea the least competitive. Crop yield data provided strong evidence of the redistribution of root activity following root pruning, with competition increasing on the unpruned side of tree rows. Thus, one-sided root pruning will be useful in only a few circumstances.

Modeling Long-Term Corn Yield Response to Nitrogen Rate and Crop Rotation

PubMed Central

Puntel, Laila A.; Sawyer, John E.; Barker, Daniel W.; Dietzel, Ranae; Poffenbarger, Hanna; Castellano, Michael J.; Moore, Kenneth J.; Thorburn, Peter; Archontoulis, Sotirios V.

2016-01-01

Improved prediction of optimal N fertilizer rates for corn (Zea mays L.) can reduce N losses and increase profits. We tested the ability of the Agricultural Production Systems sIMulator (APSIM) to simulate corn and soybean (Glycine max L.) yields, the economic optimum N rate (EONR) using a 16-year field-experiment dataset from central Iowa, USA that included two crop sequences (continuous corn and soybean-corn) and five N fertilizer rates (0, 67, 134, 201, and 268 kg N ha-1) applied to corn. Our objectives were to: (a) quantify model prediction accuracy before and after calibration, and report calibration steps; (b) compare crop model-based techniques in estimating optimal N rate for corn; and (c) utilize the calibrated model to explain factors causing year to year variability in yield and optimal N. Results indicated that the model simulated well long-term crop yields response to N (relative root mean square error, RRMSE of 19.6% before and 12.3% after calibration), which provided strong evidence that important soil and crop processes were accounted for in the model. The prediction of EONR was more complex and had greater uncertainty than the prediction of crop yield (RRMSE of 44.5% before and 36.6% after calibration). For long-term site mean EONR predictions, both calibrated and uncalibrated versions can be used as the 16-year mean differences in EONR’s were within the historical N rate error range (40–50 kg N ha-1). However, for accurate year-by-year simulation of EONR the calibrated version should be used. Model analysis revealed that higher EONR values in years with above normal spring precipitation were caused by an exponential increase in N loss (denitrification and leaching) with precipitation. We concluded that long-term experimental data were valuable in testing and refining APSIM predictions. The model can be used as a tool to assist N management guidelines in the US Midwest and we identified five avenues on how the model can add value toward

Modeling Long-Term Corn Yield Response to Nitrogen Rate and Crop Rotation.

PubMed

Puntel, Laila A; Sawyer, John E; Barker, Daniel W; Dietzel, Ranae; Poffenbarger, Hanna; Castellano, Michael J; Moore, Kenneth J; Thorburn, Peter; Archontoulis, Sotirios V

2016-01-01

Improved prediction of optimal N fertilizer rates for corn ( Zea mays L. ) can reduce N losses and increase profits. We tested the ability of the Agricultural Production Systems sIMulator (APSIM) to simulate corn and soybean ( Glycine max L. ) yields, the economic optimum N rate (EONR) using a 16-year field-experiment dataset from central Iowa, USA that included two crop sequences (continuous corn and soybean-corn) and five N fertilizer rates (0, 67, 134, 201, and 268 kg N ha -1 ) applied to corn. Our objectives were to: (a) quantify model prediction accuracy before and after calibration, and report calibration steps; (b) compare crop model-based techniques in estimating optimal N rate for corn; and (c) utilize the calibrated model to explain factors causing year to year variability in yield and optimal N. Results indicated that the model simulated well long-term crop yields response to N (relative root mean square error, RRMSE of 19.6% before and 12.3% after calibration), which provided strong evidence that important soil and crop processes were accounted for in the model. The prediction of EONR was more complex and had greater uncertainty than the prediction of crop yield (RRMSE of 44.5% before and 36.6% after calibration). For long-term site mean EONR predictions, both calibrated and uncalibrated versions can be used as the 16-year mean differences in EONR's were within the historical N rate error range (40-50 kg N ha -1 ). However, for accurate year-by-year simulation of EONR the calibrated version should be used. Model analysis revealed that higher EONR values in years with above normal spring precipitation were caused by an exponential increase in N loss (denitrification and leaching) with precipitation. We concluded that long-term experimental data were valuable in testing and refining APSIM predictions. The model can be used as a tool to assist N management guidelines in the US Midwest and we identified five avenues on how the model can add value toward

Strong Libraries, Strong Scores

ERIC Educational Resources Information Center

Gray, Carlyn

2006-01-01

This article talks about the first-ever Texas Conference on School Libraries on April 6, 2005 that was attended by one hundred thirty-five school administrators and trustees. The miniconference, entitled Strong Libraries, Strong Scores, was held at the Austin Hilton, Austin, Texas during the Texas Library Association's Annual Conference and was…

Quenched bond randomness: Superfluidity in porous media and the strong violation of universality

DOE Office of Scientific and Technical Information (OSTI.GOV)

Falicov, A.; Berker, A.N.

1997-04-01

The effects of quenched bond randomness are most readily studied with superfluidity immersed in a porous medium. A lattice model for {sup 3}He-{sup 4}He mixtures and incomplete {sup 4}He fillings in aerogel yields the signature effect of bond randomness, namely the conversion of symmetry-breaking first-order phase transitions into second-order phase transitions, the A-line reaching zero temperature, and the elimination of non-symmetry-breaking first-order phase transitions. The model recognizes the importance of the connected nature of aerogel randomness and thereby yields superfluidity at very low {sup 4}He concentrations, a phase separation entirely within the superfluid phase, and the order-parameter contrast between mixturesmore » and incomplete fillings, all in agreement with experiments. The special properties of the helium mixture/aerogel system are distinctly linked to the aerogel properties of connectivity, randomness, and tenuousness, via the additional study of a regularized {open_quote}jungle-gym{close_quotes} aerogel. Renormalization-group calculations indicate that a strong violation of the empirical universality principle of critical phenomena occurs under quenched bond randomness. It is argued that helium/aerogel critical properties reflect this violation and further experiments are suggested. Renormalization-group analysis also shows that, adjoiningly to the strong universality violation (which hinges on the occurrence or non-occurrence of asymptotic strong coupling-strong randomness under resealing), there is a new {open_quotes}hyperuniversality{close_quotes} at phase transitions with asymptotic strong coupling-strong randomness behavior, for example assigning the same critical exponents to random-bond tricriticality and random-field criticality.« less

Suspensions of Noncolloidal Particles in Yield Stress Fluids: Experimental and Micromechanical Approaches

NASA Astrophysics Data System (ADS)

Mahaut, Fabien; Bertrand, François; Coussot, Philippe; Chateau, Xavier; Ovarlez, Guillaume

2008-07-01

We study experimentally and theoretically the behavior of suspensions of noncolloidal particles in yield stress fluids. We develop procedures and materials that allow focusing on the purely mechanical contribution of the particles to the yield stress fiuid behavior, allowing relating the macroscopic properties of these suspensions to the mechanical properties of the yield stress fluid and the particle volume fraction. We find that the elastic modulus/concentration relationship follows a Krieger-Dougherty law, and show that the yield stress/concentration relationship is related to the elastic modulus/concentration relationship through a very simple law, in agreement with a micromechanical analysis. We finally present evidence for shear-induced migration in the flows of these suspensions.

Evidence for a weakening strength of temperature-corn yield relation in the United States during 1980–2010

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leng, Guoyong

Temperature is known to be correlated with crop yields, causing reduction of crop yield with climate warming without adaptations or CO2 fertilization effects. The historical temperature-crop yield relation has often been used for informing future changes. This relationship, however, may change over time following alternations in other environmental factors. Results show that the strength of the relationship between the interannual variability of growing season temperature and corn yield (RGST_CY) has declined in the United States between 1980 and 2010 with a loss in the statistical significance. The regression slope which represents the anomalies in corn yield that occur in associationmore » with 1 degree temperature anomaly has decreased significantly from -6.9%/K of the first half period to -2.4%/K~-3.5%/K of the second half period. This implies that projected corn yield reduction will be overestimated by a fact of 2 in a given warming scenario, if the corn-temperature relation is derived from the earlier historical period. Changes in RGST_CY are mainly observed in Midwest Corn Belt and central High Plains, and are well reproduced by 11 process-based crop models. In Midwest rain-fed systems, the decrease of negative temperature effects coincides with an increase in water availability by precipitation. In irrigated areas where water stress is minimized, the decline of beneficial temperature effects is significantly related to the increase in extreme hot days. The results indicate that an extrapolation of historical yield response to temperature may bias the assessment of agriculture vulnerability to climate change. Efforts to reduce climate impacts on agriculture should pay attention not only to climate change, but also to changes in climate-crop yield relations. There are some caveats that should be acknowledged as the analysis is restricted to the changes in the linear relation between growing season mean temperature and corn yield for the specific study

Yield gaps and yield relationships in US soybean production systems

USDA-ARS?s Scientific Manuscript database

The magnitude of yield gaps (YG) (potential yield – farmer yield) provides some indication of the prospects for increasing crop yield to meet the food demands of future populations. Quantile regression analysis was applied to county soybean [Glycine max (L.) Merrill] yields (1971 – 2011) from Kentuc...

Separating heat stress from moisture stress: analyzing yield response to high temperature in irrigated maize

NASA Astrophysics Data System (ADS)

Carter, Elizabeth K.; Melkonian, Jeff; Riha, Susan J.; Shaw, Stephen B.

2016-09-01

Several recent studies have indicated that high air temperatures are limiting maize (Zea mays L.) yields in the US Corn Belt and project significant yield losses with expected increases in growing season temperatures. Further work has suggested that high air temperatures are indicative of high evaporative demand, and that decreases in maize yields which correlate to high temperatures and vapor pressure deficits (VPD) likely reflect underlying soil moisture limitations. It remains unclear whether direct high temperature impacts on yields, independent of moisture stress, can be observed under current temperature regimes. Given that projected high temperature and moisture may not co-vary the same way as they have historically, quantitative analyzes of direct temperature impacts are critical for accurate yield projections and targeted mitigation strategies under shifting temperature regimes. To evaluate yield response to above optimum temperatures independent of soil moisture stress, we analyzed climate impacts on irrigated maize yields obtained from the National Corn Growers Association (NCGA) corn yield contests for Nebraska, Kansas and Missouri. In irrigated maize, we found no evidence of a direct negative impact on yield by daytime air temperature, calculated canopy temperature, or VPD when analyzed seasonally. Solar radiation was the primary yield-limiting climate variable. Our analyses suggested that elevated night temperature impacted yield by increasing rates of phenological development. High temperatures during grain-fill significantly interacted with yields, but this effect was often beneficial and included evidence of acquired thermo-tolerance. Furthermore, genetics and management—information uniquely available in the NCGA contest data—explained more yield variability than climate, and significantly modified crop response to climate. Thermo-acclimation, improved genetics and changes to management practices have the potential to partially or completely

Weak Evidence of Regeneration Habitat but Strong Evidence of Regeneration Niche for a Leguminous Shrub

PubMed Central

Delerue, Florian; Gonzalez, Maya; Michalet, Richard; Pellerin, Sylvain; Augusto, Laurent

2015-01-01

The identification of an ecological niche specific to the regeneration phase has mobilised significant attention. However, the importance of the regeneration niche concept remains unclear. Our main objective was to study the existence of such a regeneration niche for a leguminous shrub, Ulex europaeus. This study was carried out in southwest France in the context of water and nutrient stresses (mainly phosphorus limitation) due to the presence of nutrient-poor sandy soils. We analysed the regeneration of the species from the germination of seeds and emergence of new seedlings until the seedlings reached young shrub size. Our design included a P fertilisation treatment. We also investigated microsite characteristics (micro-topography and vegetation development) as they can interact with meteorological conditions and determine water availability for seeds and seedlings. We found that P availability controlled seedling growth and the time necessary to reach young shrub size. Water availability appeared to impact the species germination and seedlings survival. We also found that P and water availability depended on the interactions between microsite characteristics and climatic variations. Finally we found evidence that P and water availability are important ecological factors shaping the regeneration niche of the species, but we found weak evidence that any microsite would be appropriate for the regeneration of the species in the long term. Future studies regarding regeneration niches need to distinguish more clearly the ecological factors important for regeneration (the regeneration niche per se) and the physical world where the seedlings appear and develop (the regeneration habitat). PMID:26098877

Measurement of the Cabibbo-Kobayashi-Maskawa Angle {gamma} in B{sup {+-}}{yields}D{sup (*)}K{sup {+-}} Decays with a Dalitz Analysis of D{yields}K{sub S}{sup 0}{pi}{sup -}{pi}{sup +}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aubert, B.; Barate, R.; Boutigny, D.

2005-09-16

We report on a measurement of the Cabibbo-Kobayashi-Maskawa CP-violating phase {gamma} through a Dalitz analysis of neutral D decays to K{sub S}{sup 0}{pi}{sup -}{pi}{sup +} in the processes B{sup {+-}}{yields}D{sup (*)}K{sup {+-}}, D*{yields}D{pi}{sup 0}, D{gamma}. Using a sample of 227x10{sup 6} BB pairs collected by the BABAR detector, we measure the amplitude ratios r{sub B}=0.12{+-}0.08{+-}0.03{+-}0.04 and r{sub B}*=0.17{+-}0.10{+-}0.03{+-}0.03, the relative strong phases {delta}{sub B}=(104{+-}45{sub -21-24}{sup +17+16}) deg. and {delta}{sub B}*=(-64{+-}41{sub -12}{sup +14}{+-}15) deg. between the amplitudes A(B{sup -}{yields}D{sup (*)0}K{sup -}) and A(B{sup -}{yields}D{sup (*)0}K{sup -}), and {gamma}=(70{+-}31{sub -10-11}{sup +12+14}) deg. The first error is statistical, the second is the experimentalmore » systematic uncertainty, and the third reflects the Dalitz model uncertainty. The results for the strong and weak phases have a twofold ambiguity.« less

Equatorial magnetic Rossby waves — evidence for a thin, strongly-buoyant stratified layer in earth's core

NASA Astrophysics Data System (ADS)

Knezek, Nicholas; Buffett, Bruce

2017-04-01

A low density stratified layer at the top of Earth's core has been proposed by many authors on the basis of chemical and thermodynamic arguments and has implications for Earth's thermal history, core energetics, and core-mantle interactions. Past studies claiming to detect a layer using perturbations in seismic wave speeds are contentious due to the extremely small magnitude of the detected signal. Recently, several studies have instead argued for the existence of a stratified layer by hypothesizing that oscillations in the observed geomagnetic field arise from waves propagating in the layer. In particular, 60 year oscillations in dipole strength have been attributed to global MAC waves, and 8 year oscillations of secular acceleration have been attributed to equatorially-trapped waves. We use a new hybrid finite-volume and Fourier numerical method we developed to model magnetohydrodynamic waves in a thin layer and show that a thin, strongly buoyant layer can produce equatorially-trapped waves with similar structures and periods to the observed 8 year signal. Using these simulated wave structures, we provide additional evidence for the existence of several propagating wave modes and place constraints on estimates for the wave periods, stratified layer thickness, and strength of buoyancy within the layer.

Optimizing rice yields while minimizing yield-scaled global warming potential.

PubMed

Pittelkow, Cameron M; Adviento-Borbe, Maria A; van Kessel, Chris; Hill, James E; Linquist, Bruce A

2014-05-01

To meet growing global food demand with limited land and reduced environmental impact, agricultural greenhouse gas (GHG) emissions are increasingly evaluated with respect to crop productivity, i.e., on a yield-scaled as opposed to area basis. Here, we compiled available field data on CH4 and N2 O emissions from rice production systems to test the hypothesis that in response to fertilizer nitrogen (N) addition, yield-scaled global warming potential (GWP) will be minimized at N rates that maximize yields. Within each study, yield N surplus was calculated to estimate deficit or excess N application rates with respect to the optimal N rate (defined as the N rate at which maximum yield was achieved). Relationships between yield N surplus and GHG emissions were assessed using linear and nonlinear mixed-effects models. Results indicate that yields increased in response to increasing N surplus when moving from deficit to optimal N rates. At N rates contributing to a yield N surplus, N2 O and yield-scaled N2 O emissions increased exponentially. In contrast, CH4 emissions were not impacted by N inputs. Accordingly, yield-scaled CH4 emissions decreased with N addition. Overall, yield-scaled GWP was minimized at optimal N rates, decreasing by 21% compared to treatments without N addition. These results are unique compared to aerobic cropping systems in which N2 O emissions are the primary contributor to GWP, meaning yield-scaled GWP may not necessarily decrease for aerobic crops when yields are optimized by N fertilizer addition. Balancing gains in agricultural productivity with climate change concerns, this work supports the concept that high rice yields can be achieved with minimal yield-scaled GWP through optimal N application rates. Moreover, additional improvements in N use efficiency may further reduce yield-scaled GWP, thereby strengthening the economic and environmental sustainability of rice systems. © 2013 John Wiley & Sons Ltd.

Diverse convergent evidence in the genetic analysis of complex disease: coordinating omic, informatic, and experimental evidence to better identify and validate risk factors

PubMed Central

2014-01-01

In omic research, such as genome wide association studies, researchers seek to repeat their results in other datasets to reduce false positive findings and thus provide evidence for the existence of true associations. Unfortunately this standard validation approach cannot completely eliminate false positive conclusions, and it can also mask many true associations that might otherwise advance our understanding of pathology. These issues beg the question: How can we increase the amount of knowledge gained from high throughput genetic data? To address this challenge, we present an approach that complements standard statistical validation methods by drawing attention to both potential false negative and false positive conclusions, as well as providing broad information for directing future research. The Diverse Convergent Evidence approach (DiCE) we propose integrates information from multiple sources (omics, informatics, and laboratory experiments) to estimate the strength of the available corroborating evidence supporting a given association. This process is designed to yield an evidence metric that has utility when etiologic heterogeneity, variable risk factor frequencies, and a variety of observational data imperfections might lead to false conclusions. We provide proof of principle examples in which DiCE identified strong evidence for associations that have established biological importance, when standard validation methods alone did not provide support. If used as an adjunct to standard validation methods this approach can leverage multiple distinct data types to improve genetic risk factor discovery/validation, promote effective science communication, and guide future research directions. PMID:25071867

Application of wheat yield model to United States and India. [Great Plains

NASA Technical Reports Server (NTRS)

Feyerherm, A. M. (Principal Investigator)

1977-01-01

The author has identified the following significant results. The wheat yield model was applied to the major wheat-growing areas of the US and India. In the US Great Plains, estimates from the winter and spring wheat models agreed closely with USDA-SRS values in years with the lowest yields, but underestimated in years with the highest yields. Application to the Eastern Plains and Northwest indicated the importance of cultural factors, as well as meteorological ones in the model. It also demonstrated that the model could be used, in conjunction with USDA-SRRS estimates, to estimate yield losses due to factors not included in the model, particularly diseases and freezes. A fixed crop calendar for India was built from a limited amount of available plot data from that country. Application of the yield model gave measurable evidence that yield variation from state to state was due to different mixes of levels of meteorological and cultural factors.

Simulated vs. empirical weather responsiveness of crop yields: US evidence and implications for the agricultural impacts of climate change

DOE PAGES

Mistry, Malcolm N.; Wing, Ian Sue; De Cian, Enrica

2017-07-10

Global gridded crop models (GGCMs) are the workhorse of assessments of the agricultural impacts of climate change. Yet the changes in crop yields projected by different models in response to the same meteorological forcing can differ substantially. Through an inter-method comparison, we provide a first glimpse into the origins and implications of this divergence—both among GGCMs and between GGCMs and historical observations. We examine yields of rainfed maize, wheat, and soybeans simulated by six GGCMs as part of the Inter-Sectoral Impact Model Intercomparison Project-Fast Track (ISIMIP-FT) exercise, comparing 1981–2004 hindcast yields over the coterminous United States (US) against US Departmentmore » of Agriculture (USDA) time series for about 1000 counties. Leveraging the empirical climate change impacts literature, we estimate reduced-form econometric models of crop yield responses to temperature and precipitation exposures for both GGCMs and observations. We find that up to 60% of the variance in both simulated and observed yields is attributable to weather variation. A majority of the GGCMs have difficulty reproducing the observed distribution of percentage yield anomalies, and exhibit aggregate responses that show yields to be more weather-sensitive than in the observational record over the predominant range of temperature and precipitation conditions. In conclusion, this disparity is largely attributable to heterogeneity in GGCMs' responses, as opposed to uncertainty in historical weather forcings, and is responsible for widely divergent impacts of climate on future crop yields.« less

Simulated vs. empirical weather responsiveness of crop yields: US evidence and implications for the agricultural impacts of climate change

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mistry, Malcolm N.; Wing, Ian Sue; De Cian, Enrica

Global gridded crop models (GGCMs) are the workhorse of assessments of the agricultural impacts of climate change. Yet the changes in crop yields projected by different models in response to the same meteorological forcing can differ substantially. Through an inter-method comparison, we provide a first glimpse into the origins and implications of this divergence—both among GGCMs and between GGCMs and historical observations. We examine yields of rainfed maize, wheat, and soybeans simulated by six GGCMs as part of the Inter-Sectoral Impact Model Intercomparison Project-Fast Track (ISIMIP-FT) exercise, comparing 1981–2004 hindcast yields over the coterminous United States (US) against US Departmentmore » of Agriculture (USDA) time series for about 1000 counties. Leveraging the empirical climate change impacts literature, we estimate reduced-form econometric models of crop yield responses to temperature and precipitation exposures for both GGCMs and observations. We find that up to 60% of the variance in both simulated and observed yields is attributable to weather variation. A majority of the GGCMs have difficulty reproducing the observed distribution of percentage yield anomalies, and exhibit aggregate responses that show yields to be more weather-sensitive than in the observational record over the predominant range of temperature and precipitation conditions. In conclusion, this disparity is largely attributable to heterogeneity in GGCMs' responses, as opposed to uncertainty in historical weather forcings, and is responsible for widely divergent impacts of climate on future crop yields.« less

Simulated vs. empirical weather responsiveness of crop yields: US evidence and implications for the agricultural impacts of climate change

NASA Astrophysics Data System (ADS)

Mistry, Malcolm N.; Wing, Ian Sue; De Cian, Enrica

2017-07-01

Global gridded crop models (GGCMs) are the workhorse of assessments of the agricultural impacts of climate change. Yet the changes in crop yields projected by different models in response to the same meteorological forcing can differ substantially. Through an inter-method comparison, we provide a first glimpse into the origins and implications of this divergence—both among GGCMs and between GGCMs and historical observations. We examine yields of rainfed maize, wheat, and soybeans simulated by six GGCMs as part of the Inter-Sectoral Impact Model Intercomparison Project-Fast Track (ISIMIP-FT) exercise, comparing 1981-2004 hindcast yields over the coterminous United States (US) against US Department of Agriculture (USDA) time series for about 1000 counties. Leveraging the empirical climate change impacts literature, we estimate reduced-form econometric models of crop yield responses to temperature and precipitation exposures for both GGCMs and observations. We find that up to 60% of the variance in both simulated and observed yields is attributable to weather variation. A majority of the GGCMs have difficulty reproducing the observed distribution of percentage yield anomalies, and exhibit aggregate responses that show yields to be more weather-sensitive than in the observational record over the predominant range of temperature and precipitation conditions. This disparity is largely attributable to heterogeneity in GGCMs’ responses, as opposed to uncertainty in historical weather forcings, and is responsible for widely divergent impacts of climate on future crop yields.

Unified Time and Frequency Picture of Ultrafast Atomic Excitation in Strong Laser Fields

NASA Astrophysics Data System (ADS)

Zimmermann, H.; Patchkovskii, S.; Ivanov, M.; Eichmann, U.

2017-01-01

Excitation and ionization in strong laser fields lies at the heart of such diverse research directions as high-harmonic generation and spectroscopy, laser-induced diffraction imaging, emission of femtosecond electron bunches from nanotips, self-guiding, filamentation and mirrorless lasing during propagation of light in atmospheres. While extensive quantum mechanical and semiclassical calculations on strong-field ionization are well backed by sophisticated experiments, the existing scattered theoretical work aiming at a full quantitative understanding of strong-field excitation lacks experimental confirmation. Here we present experiments on strong-field excitation in both the tunneling and multiphoton regimes and their rigorous interpretation by time dependent Schrödinger equation calculations, which finally consolidates the seemingly opposing strong-field regimes with their complementary pictures. Most strikingly, we observe an unprecedented enhancement of excitation yields, which opens new possibilities in ultrafast strong-field control of Rydberg wave packet excitation and laser intensity characterization.

Refined mapping of a gene responsible for Fukuyama-type congenital muscular dystrophy: Evidence for strong linkage disequilibrium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Toda, Tatsushi; Ikegawa, Shiro; Okui, Keiko

1994-11-01

Fukuyama-type congenital muscular dystrophy (FCMD), the second most common form of childhood muscular dystrophy in Japan, is an autosomal recessive severe muscular dystrophy associated with an anomaly of the brain. After our initial mapping of the FCMD locus to chromosome 9q31-33, we further defined the locus within a region of {approximately}5 cM between loci D9S127 and CA246, by homozygosity mapping in patients born to consanguineous marriages and by recombination analyses in other families. We also found evidence for strong linkage disequilibrium between FCMD and a polymorphic microsatellite marker, mfd220, which showed no recombination and a lod score of (Z) 17.49.more » A {open_quotes}111-bp{close_quotes} allele for the mfd220 was observed in 22 (34%) of 64 FCMD chromosomes, but it was present in only 1 of 120 normal chromosomes. This allelic association with FCMD was highly significant ({chi}{sup 2} = 50.7; P < .0001). Hence, we suspect that the FCMD gene could lie within a few hundred kilobases of the mfd220 locus. 32 refs., 2 figs., 2 tabs.« less

Use of vegetation health data for estimation of aus rice yield in bangladesh.

PubMed

Rahman, Atiqur; Roytman, Leonid; Krakauer, Nir Y; Nizamuddin, Mohammad; Goldberg, Mitch

2009-01-01

Rice is a vital staple crop for Bangladesh and surrounding countries, with interannual variation in yields depending on climatic conditions. We compared Bangladesh yield of aus rice, one of the main varieties grown, from official agricultural statistics with Vegetation Health (VH) Indices [Vegetation Condition Index (VCI), Temperature Condition Index (TCI) and Vegetation Health Index (VHI)] computed from Advanced Very High Resolution Radiometer (AVHRR) data covering a period of 15 years (1991-2005). A strong correlation was found between aus rice yield and VCI and VHI during the critical period of aus rice development that occurs during March-April (weeks 8-13 of the year), several months in advance of the rice harvest. Stepwise principal component regression (PCR) was used to construct a model to predict yield as a function of critical-period VHI. The model reduced the yield prediction error variance by 62% compared with a prediction of average yield for each year. Remote sensing is a valuable tool for estimating rice yields well in advance of harvest and at a low cost.

Use of Vegetation Health Data for Estimation of Aus Rice Yield in Bangladesh

PubMed Central

Rahman, Atiqur; Roytman, Leonid; Krakauer, Nir Y.; Nizamuddin, Mohammad; Goldberg, Mitch

2009-01-01

Rice is a vital staple crop for Bangladesh and surrounding countries, with interannual variation in yields depending on climatic conditions. We compared Bangladesh yield of aus rice, one of the main varieties grown, from official agricultural statistics with Vegetation Health (VH) Indices [Vegetation Condition Index (VCI), Temperature Condition Index (TCI) and Vegetation Health Index (VHI)] computed from Advanced Very High Resolution Radiometer (AVHRR) data covering a period of 15 years (1991–2005). A strong correlation was found between aus rice yield and VCI and VHI during the critical period of aus rice development that occurs during March–April (weeks 8–13 of the year), several months in advance of the rice harvest. Stepwise principal component regression (PCR) was used to construct a model to predict yield as a function of critical-period VHI. The model reduced the yield prediction error variance by 62% compared with a prediction of average yield for each year. Remote sensing is a valuable tool for estimating rice yields well in advance of harvest and at a low cost. PMID:22574057

Crop yield changes induced by emissions of individual climate-altering pollutants

NASA Astrophysics Data System (ADS)

Shindell, Drew T.

2016-08-01

Climate change damages agriculture, causing deteriorating food security and increased malnutrition. Many studies have examined the role of distinct physical processes, but impacts have not been previously attributed to individual pollutants. Using a simple model incorporating process-level results from detailed models, here I show that although carbon dioxide (CO2) is the largest driver of climate change, other drivers appear to dominate agricultural yield changes. I calculate that anthropogenic emissions to date have decreased global agricultural yields by 9.5 ± 3.0%, with roughly 93% stemming from non-CO2 emissions, including methane (-5.2 ± 1.7%) and halocarbons (-1.4 ± 0.4%). The differing impacts stem from atmospheric composition responses: CO2 fertilizes crops, offsetting much of the loss induced by warming; halocarbons do not fertilize; methane leads to minimal fertilization but increases surface ozone which augments warming-induced losses. By the end of the century, strong CO2 mitigation improves agricultural yields by ˜3 ± 5%. In contrast, strong methane and hydrofluorocarbon mitigation improve yields by ˜16 ± 5% and ˜5 ± 4%, respectively. These are the first quantitative analyses to include climate, CO2 and ozone simultaneously, and hence, additional studies would be valuable. Nonetheless, as policy makers have leverage over pollutant emissions rather than isolated processes, the perspective presented here may be more useful for decision making than that in the prior work upon which this study builds. The results suggest that policies should target a broad portfolio of pollutant emissions in order to optimize mitigation of societal damages.

Is the evidence supporting dental procedures strong? A survey of Cochrane systematic reviews in oral health.

PubMed

Faggion, Clovis Mariano

2012-09-01

Every day a large number and variety of dental procedures are performed in clinical dental practice. There is, however, no information on the overall quality of evidence supporting these procedures. The objective of this study was to assess whether several common dental procedures are based on sound evidence. All Cochrane systematic reviews (CSR) published in dentistry were surveyed. The authors' conclusions about the quality of evidence supporting a specific clinical treatment were used as the measure of outcome. The evidence was considered adequate if the authors did not clearly state the evidence was weak in the conclusions while also suggesting some evidence of the effectiveness of the therapy. Of 120 CSRs assessed, in only 26 (22.0% of the reviews) was the quality of evidence regarded as adequate for supporting clinical decisions, although some methodological limitations were identified in the full text of these reviews. Moreover, the authors of most reviews reported weak or unavailable evidence. On the basis of CSRs, the overall quality of evidence can be regarded as low or nonexistent for most of the dental procedures assessed. The information reported may guide future research. Copyright © 2012 Elsevier Inc. All rights reserved.

Evidence of strong ocean heating during glacial periods

NASA Astrophysics Data System (ADS)

Zimov, S. A.; Zimov, N.

2013-12-01

Numerous hypotheses have addressed glacial-interglacial climatic dynamics, but none of them explain the sharp 25C temperature increase in Greenland in the last deglaciation (Cuffey et al. 1995; Dahl-Jensen et al. 1998). These robust data were obtained through analyzing the temperature profile in the Greenland ice sheet where cold from the last glaciation is preserved in the depth of the glacial sheet. We suggest that during glaciations the ocean accumulated energy: interior ocean water heated up to ~20-30C and during deglaciation this energy is released. In the analogy with reconstructing the ice sheet temperature profiles, the most reliable proof of ocean interior warming during the last glaciation is the heat flux profiles in the bottom sediments. In the final reports based on temperature measurements conducted during the DSDP (Deep Sea Drilling Project) it is stated that heat flux in the bottom sediments doesn't vary with depth and consequently there were no substantial temperature changes in the ocean interior during the last glacial cycle, and heat flux on the surface of the ocean bottom is the geothermal heat flux (Erickson et al., 1975, Hyndman et al., 1987). However, we have critically investigated data in all initial reports of all deep sea drilling projects and have noticed that all temperature data show that heat flow decreases strongly with depth (a minimum of 40 mW/m2), i.e. most of the heat flux detected on the surface of the ocean floor is not the geothermal heat flux but remaining heat that bottom sediments release. Sharp shifts in heat flow are seen within boreholes at depths crossing gas hydrate bottom. All this means that during the last glacial period interior water temperature was on 25-30C degrees warmer. Conversely, in isolated seas heat flow in the sediments shows little change with depth.

Synergistic interactions of ecosystem services: florivorous pest control boosts crop yield increase through insect pollination

PubMed Central

Albrecht, Matthias

2016-01-01

Insect pollination and pest control are pivotal functions sustaining global food production. However, they have mostly been studied in isolation and how they interactively shape crop yield remains largely unexplored. Using controlled field experiments, we found strong synergistic effects of insect pollination and simulated pest control on yield quantity and quality. Their joint effect increased yield by 23%, with synergistic effects contributing 10%, while their single contributions were 7% and 6%, respectively. The potential economic benefit for a farmer from the synergistic effects (12%) was 1.8 times greater than their individual contributions (7% each). We show that the principal underlying mechanism was a pronounced pest-induced reduction in flower lifetime, resulting in a strong reduction in the number of pollinator visits a flower receives during its lifetime. Our findings highlight the importance of non-additive interactions among ecosystem services (ES) when valuating, mapping or predicting them and reveal fundamental implications for ecosystem management and policy aimed at maximizing ES for sustainable agriculture. PMID:26865304

J0454-0309: evidence of a strong lensing fossil group falling into a poor galaxy cluster

NASA Astrophysics Data System (ADS)

Schirmer, M.; Suyu, S.; Schrabback, T.; Hildebrandt, H.; Erben, T.; Halkola, A.

2010-05-01

Aims: We have discovered a strong lensing fossil group (J0454) projected near the well-studied cluster MS0451-0305. Using the large amount of available archival data, we compare J0454 to normal groups and clusters. A highly asymmetric image configuration of the strong lens enables us to study the substructure of the system. Methods: We used multicolour Subaru/Suprime-Cam and CFHT/Megaprime imaging, together with Keck spectroscopy to identify member galaxies. A VLT/FORS2 spectrum was taken to determine the redshifts of the brightest elliptical and the lensed arc. Using HST/ACS images, we determined the group's weak lensing signal and modelled the strong lens system. This is the first time that a fossil group is analysed with lensing methods. The X-ray luminosity and temperature were derived from XMM-Newton data. Results: J0454 is located at z = 0.26, with a gap of 2.5 mag between the brightest and second brightest galaxies within half the virial radius. Outside a radius of 1.5 Mpc, we find two filaments extending over 4 Mpc, and within we identify 31 members spectroscopically and 33 via the red sequence with i < 22 mag. They segregate into spirals (σ_v = 590 km s-1) and a central concentration of ellipticals (σ_v = 480 km s-1), establishing a morphology-density relation. Weak lensing and cluster richness relations yield consistent values of r200 = 810-850 kpc and M200 = (0.75-0.90) × 1014 M_⊙. The brightest group galaxy (BGG) is inconsistent with the dynamic centre of J0454. It strongly lenses a galaxy at z = 2.1 ± 0.3, and we model the lens with a pseudo-isothermal elliptical mass distribution. A high external shear, and a discrepancy between the Einstein radius and the weak lensing velocity dispersion requires that the BGG must be offset from J0454's dark halo centre by at least 90-130 kpc. The X-ray halo is offset by 24 ± 16 kpc from the BGG, shows no signs of a cooling flow and can be fit by a single β-model. With LX = (1.4 ± 0.2) × 1043 erg s-1 J0454

Specific yield: compilation of specific yields for various materials

USGS Publications Warehouse

Johnson, A.I.

1967-01-01

Specific yield is defined as the ratio of (1) the volume of water that a saturated rock or soil will yield by gravity to (2) the total volume of the rock or soft. Specific yield is usually expressed as a percentage. The value is not definitive, because the quantity of water that will drain by gravity depends on variables such as duration of drainage, temperature, mineral composition of the water, and various physical characteristics of the rock or soil under consideration. Values of specific yields nevertheless offer a convenient means by which hydrologists can estimate the water-yielding capacities of earth materials and, as such, are very useful in hydrologic studies. The present report consists mostly of direct or modified quotations from many selected reports that present and evaluate methods for determining specific yield, limitations of those methods, and results of the determinations made on a wide variety of rock and soil materials. Although no particular values are recommended in this report, a table summarizes values of specific yield, and their averages, determined for 10 rock textures. The following is an abstract of the table. [Table

Yield and yield gaps in central U.S. corn production systems

USDA-ARS?s Scientific Manuscript database

The magnitude of yield gaps (YG) (potential yield – farmer yield) provides some indication of the prospects for increasing crop yield. Quantile regression analysis was applied to county maize (Zea mays L.) yields (1972 – 2011) from Kentucky, Iowa and Nebraska (irrigated) (total of 115 counties) to e...

Spatially: resolved heterogeneous dynamics in a strong colloidal gel

NASA Astrophysics Data System (ADS)

Buzzaccaro, Stefano; Alaimo, Matteo David; Secchi, Eleonora; Piazza, Roberto

2015-05-01

We re-examine the classical problem of irreversible colloid aggregation, showing that the application of Digital Fourier Imaging (DFI), a class of optical correlation methods that combine the power of light scattering and imaging, allows one to pick out novel useful evidence concerning the restructuring processes taking place in a strong colloidal gel. In particular, the spatially-resolved displacement fields provided by DFI strongly suggest that the temporally-intermittent local rearrangements taking place in the course of gel ageing are characterized by very long-ranged spatial correlations.

The STRONG STAR Multidisciplinary PTSD Research Consortium

DTIC Science & Technology

2009-09-01

superior A.5 Role of the Serotonin Transporter and Serotonergic Hypotheses related to Alcoholism Vulnerability Due to Low Serotonin. Strong...evidence shows that the biological vulnerability of EOA patients may be related to a serotonergic dysfunction (Johnson, 2000; Johnson and Ait-Daoud...transporter (Johnson et al., 2008). These findings of reduced serotonergic functioning in L-carriers is contrary to previous data indicating that the L

Diphotons, new vacuum angles, and strong CP

DOE Office of Scientific and Technical Information (OSTI.GOV)

Draper, Patrick; McKeen, David

The Standard Model contains a well-understood, natural, spin-0 diphoton resonance: the π 0. Numerous studies have pointed out that the hint of a new diphoton resonance at 750 GeV could be a pion analog, identified with the pseudo-Nambu-Goldstone boson of a chiral symmetry spontaneously broken by new strong dynamics at the TeV scale. These “hypercolor” models are generically expected to violate parity through a topological angle θ ~. We discuss the physics of θ ~ and its impact on the phenomenology of the new sector. We also describe some of the theoretical implications of a nonzero θ ~. In particular,more » θ ~ can generate an O(1) threshold correction to the QCD vacuum angle θ near the TeV scale, sharply constraining ultraviolet solutions to the strong CP problem. Furthermore, finding that θ ~ is small may be interpreted as evidence in favor of UV solutions to strong CP, particularly those based on spontaneously broken P or CP symmetries.« less

Diphotons, new vacuum angles, and strong CP

DOE PAGES

Draper, Patrick; McKeen, David

2016-04-20

The Standard Model contains a well-understood, natural, spin-0 diphoton resonance: the π 0. Numerous studies have pointed out that the hint of a new diphoton resonance at 750 GeV could be a pion analog, identified with the pseudo-Nambu-Goldstone boson of a chiral symmetry spontaneously broken by new strong dynamics at the TeV scale. These “hypercolor” models are generically expected to violate parity through a topological angle θ ~. We discuss the physics of θ ~ and its impact on the phenomenology of the new sector. We also describe some of the theoretical implications of a nonzero θ ~. In particular,more » θ ~ can generate an O(1) threshold correction to the QCD vacuum angle θ near the TeV scale, sharply constraining ultraviolet solutions to the strong CP problem. Furthermore, finding that θ ~ is small may be interpreted as evidence in favor of UV solutions to strong CP, particularly those based on spontaneously broken P or CP symmetries.« less

Strong and Long Makes Short: Strong-Pump Strong-Probe Spectroscopy.

PubMed

Gelin, Maxim F; Egorova, Dassia; Domcke, Wolfgang

2011-01-20

We propose a new time-domain spectroscopic technique that is based on strong pump and probe pulses. The strong-pump strong-probe (SPSP) technique provides temporal resolution that is not limited by the durations of the pump and probe pulses. By numerically exact simulations of SPSP signals for a multilevel vibronic model, we show that the SPSP signals exhibit electronic and vibrational beatings on time scales which are significantly shorter than the pulse durations. This suggests the possible application of SPSP spectroscopy for the real-time investigation of molecular processes that cannot be temporally resolved by pump-probe spectroscopy with weak pump and probe pulses.

Yield and Failure Behavior Investigated for Cross-Linked Phenolic Resins Using Molecular Dynamics

NASA Technical Reports Server (NTRS)

Monk, Joshua D.; Lawson, John W.

2016-01-01

Molecular dynamics simulations were conducted to fundamentally evaluate the yield and failure behavior of cross-linked phenolic resins at temperatures below the glass transition. Yield stress was investigated at various temperatures, strain rates, and degrees of cross-linking. The onset of non-linear behavior in the cross-linked phenolic structures was caused by localized irreversible molecular rearrangements through the rotation of methylene linkers followed by the formation or annihilation of neighboring hydrogen bonds. The yield stress results, with respect to temperature and strain rate, could be fit by existing models used to describe yield behavior of amorphous glasses. The degree of cross-linking only indirectly influences the maximum yield stress through its influence on glass transition temperature (Tg), however there is a strong relationship between the degree of cross-linking and the failure mechanism. Low cross-linked samples were able to separate through void formation, whereas the highly cross-linked structures exhibited bond scission.

What limits the yield of levoglucosan during fast pyrolysis of cellulose?

NASA Astrophysics Data System (ADS)

Proano-Aviles, Juan

The pyrolysis of cellulose to form levoglucosan is investigated in this study. Although the stoichiometric yield of levoglucosan from the pyrolysis of cellulose is expected to be 100%, only about 60 wt.% yields are reported in the literature. Several possible reasons for this limitation are investigated through experiments in micropyrolyzers and computational studies on the depolymerization of cellulose. Heat and mass transfer limitations in an experimental apparatus is one possible limitation on the yield of levoglucosan. Repolymerization of condensed phase reaction intermediates could prevent the formation and release of volatile levoglucosan. Thermohydrolysis of pyrolyzing cellulose to form non-volatile and thermally unstable glucose has also been proposed as a mechanism that reduces levoglucosan yields. Secondary reactions in the gas phase were also investigated to explain limitations on levoglucosan yields. Population balance models were developed to test ideas on how cellulose depolymerized to form levoglucosan at less than stoichiometric yields. These models were supported with chemical kinetic data obtained from transient pyrolysis experiments. Under carefully controlled experimental conditions, no evidence was found for heat and mass transfer effects limiting levoglucosan yields to 60 wt.% nor do secondary reactions in the condensed- or gas-phases appear to offer a satisfactory explanation. Based on modeling results, it appears levoglucosan-forming reaction rates that decrease as oligosaccharide chain length decreases is the most plausible explanation for limitations on levoglucosan yield from cellulose.

Careers in Forensics: Analysis, Evidence, and Law

ERIC Educational Resources Information Center

Torpey, Elka Maria

2009-01-01

In legal proceedings, a case is only as strong as its evidence. And whether that evidence is strong depends, in large part, on the work of forensic specialists. The field of forensics is broad and involves many kinds of workers. Some of them are involved in crimesolving. Others, such as forensic social workers or forensic economists, help to…

Evidence-Based Reform in Education

ERIC Educational Resources Information Center

Slavin, Robert E.

2017-01-01

Education policies should support the use of programs and practices with strong evidence of effectiveness. The Every Student Succeeds Act (ESSA) contains evidence standards and incentives to use programs that meet them. This provides a great opportunity for evidence to play a stronger role in decisions about education programs and practices.…

How strong is the evidence that solar ultraviolet B and vitamin D reduce the risk of cancer?: An examination using Hill's criteria for causality.

PubMed

Grant, William B

2009-01-01

The ultraviolet-B (UVB)-vitamin D-cancer hypothesis was proposed in 1980. Since then, several ecological and observational studies have examined the hypothesis, in addition to one good randomized, controlled trial. Also, the mechanisms whereby vitamin D reduces the risk of cancer have been elucidated. This report aims to examine the evidence to date with respect to the criteria for causality in a biological system first proposed by Robert Koch and later systematized by A. Bradford Hill. The criteria of most relevance are strength of association, consistency, biological gradient, plausibility/mechanisms and experimental verification. Results for several cancers generally satisfy these criteria. Results for breast and colorectal cancer satisfy the criteria best, but there is also good evidence that other cancers do as well, including bladder, esophageal, gallbladder, gastric, ovarian, rectal, renal and uterine corpus cancer, as well as Hodgkin's and non-Hodgkin's lymphoma. Several cancers have mixed findings with respect to UVB and/or vitamin D, including pancreatic and prostate cancer and melanoma. Even for these, the benefit of vitamin D seems reasonably strong. Although ecological and observational studies are not generally regarded as able to provide convincing evidence of causality, the fact that humanity has always existed with vitamin D from solar UVB irradiance means that there is a wealth of evidence to be harvested using the ecological and observational approaches. Nonetheless, additional randomized, controlled trials are warranted to further examine the link between vitamin D and cancer incidence, survival and mortality.

Strong Coupling of Localized Surface Plasmons to Excitons in Light-Harvesting Complexes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsargorodska, Anna; Cartron, Michaël L.; Vasilev, Cvetelin

Gold nanostructure arrays exhibit surface plasmon resonances that split after attaching light harvesting complexes 1 and 2 (LH1 and LH2) from purple bacteria. The splitting is attributed to strong coupling between the localized surface plasmon resonances and excitons in the light-harvesting complexes. Wild-type and mutant LH1 and LH2 from Rhodobacter sphaeroides containing different carotenoids yield different splitting energies, demonstrating that the coupling mechanism is sensitive to the electronic states in the light harvesting complexes. Plasmon–exciton coupling models reveal different coupling strengths depending on the molecular organization and the protein coverage, consistent with strong coupling. Strong coupling was also observed formore » self-assembling polypeptide maquettes that contain only chlorins. However, it is not observed for monolayers of bacteriochlorophyll, indicating that strong plasmon–exciton coupling is sensitive to the specific presentation of the pigment molecules.« less

Strong Coupling of Localized Surface Plasmons to Excitons in Light-Harvesting Complexes

DOE PAGES

Tsargorodska, Anna; Cartron, Michaël L.; Vasilev, Cvetelin; ...

2016-09-30

Gold nanostructure arrays exhibit surface plasmon resonances that split after attaching light harvesting complexes 1 and 2 (LH1 and LH2) from purple bacteria. The splitting is attributed to strong coupling between the localized surface plasmon resonances and excitons in the light-harvesting complexes. Wild-type and mutant LH1 and LH2 from Rhodobacter sphaeroides containing different carotenoids yield different splitting energies, demonstrating that the coupling mechanism is sensitive to the electronic states in the light harvesting complexes. Plasmon–exciton coupling models reveal different coupling strengths depending on the molecular organization and the protein coverage, consistent with strong coupling. Strong coupling was also observed formore » self-assembling polypeptide maquettes that contain only chlorins. However, it is not observed for monolayers of bacteriochlorophyll, indicating that strong plasmon–exciton coupling is sensitive to the specific presentation of the pigment molecules.« less

Monitoring Crop Yield in USA Using a Satellite-Based Climate-Variability Impact Index

NASA Technical Reports Server (NTRS)

Zhang, Ping; Anderson, Bruce; Tan, Bin; Barlow, Mathew; Myneni, Ranga

2011-01-01

A quantitative index is applied to monitor crop growth and predict agricultural yield in continental USA. The Climate-Variability Impact Index (CVII), defined as the monthly contribution to overall anomalies in growth during a given year, is derived from 1-km MODIS Leaf Area Index. The growing-season integrated CVII can provide an estimate of the fractional change in overall growth during a given year. In turn these estimates can provide fine-scale and aggregated information on yield for various crops. Trained from historical records of crop production, a statistical model is used to produce crop yield during the growing season based upon the strong positive relationship between crop yield and the CVII. By examining the model prediction as a function of time, it is possible to determine when the in-season predictive capability plateaus and which months provide the greatest predictive capacity.

Critical behavior in trapped strongly interacting Fermi gases

NASA Astrophysics Data System (ADS)

Taylor, E.

2009-08-01

We investigate the width of the Ginzburg critical region and experimental signatures of critical behavior in strongly interacting trapped Fermi gases close to unitarity, where the s -wave scattering length diverges. Despite the fact that the width of the critical region is of the order unity, evidence of critical behavior in the bulk thermodynamics of trapped gases is strongly suppressed by their inhomogeneity. The specific heat of a harmonically confined gas, for instance, is linear in the reduced temperature t=(T-Tc)/Tc above Tc . We also discuss the prospects of observing critical behavior in the local compressibility from measurements of the density profile.

The role of drought on wheat yield interannual variability in the Iberian Peninsula from 1929 to 2012.

PubMed

Páscoa, P; Gouveia, C M; Russo, A; Trigo, R M

2017-03-01

The production of wheat in the Iberian Peninsula is strongly affected by climate conditions being particularly vulnerable to interannual changes in precipitation and long-term trends of both rainfall and evapotranspiration. Recent trends in precipitation and temperature point to an increase in dryness in this territory, thus highlighting the need to understand the dependence of wheat yield on climate conditions. The present work aims at studying the relation between wheat yields and drought events in the Iberian Peninsula, using a multiscalar drought index, the standardized precipitation evapotranspiration index (SPEI), at various timescales. The effects of the occurrence of dry episodes on wheat yields were analyzed, on regional spatial scale for two subperiods (1929-1985 and 1986-2012). The results show that in western areas, wheat yield is positively affected by dryer conditions, whereas the opposite happens in eastern areas. The winter months have a bigger influence in the west while the east is more dependent on the spring and summer months. Moreover, in the period of 1986-2012, the simultaneous occurrence of low-yield anomalies and dry events reaches values close to 100 % over many provinces. Results suggest that May and June have a strong control on wheat yield, namely, for longer timescales (9 to 12 months). A shift in the dependence of wheat yields on climatic droughts is evidenced by the increase in the area with positive correlation and the decrease in area with negative correlation between wheat yields and SPEI, probably due to the increase of dry events.

Yield stress in amorphous solids: A mode-coupling-theory analysis

NASA Astrophysics Data System (ADS)

Ikeda, Atsushi; Berthier, Ludovic

2013-11-01

The yield stress is a defining feature of amorphous materials which is difficult to analyze theoretically, because it stems from the strongly nonlinear response of an arrested solid to an applied deformation. Mode-coupling theory predicts the flow curves of materials undergoing a glass transition and thus offers predictions for the yield stress of amorphous solids. We use this approach to analyze several classes of disordered solids, using simple models of hard-sphere glasses, soft glasses, and metallic glasses for which the mode-coupling predictions can be directly compared to the outcome of numerical measurements. The theory correctly describes the emergence of a yield stress of entropic nature in hard-sphere glasses, and its rapid growth as density approaches random close packing at qualitative level. By contrast, the emergence of solid behavior in soft and metallic glasses, which originates from direct particle interactions is not well described by the theory. We show that similar shortcomings arise in the description of the caging dynamics of the glass phase at rest. We discuss the range of applicability of mode-coupling theory to understand the yield stress and nonlinear rheology of amorphous materials.

Measurement of fission yields and isomeric yield ratios at IGISOL

NASA Astrophysics Data System (ADS)

Pomp, Stephan; Mattera, Andrea; Rakopoulos, Vasileios; Al-Adili, Ali; Lantz, Mattias; Solders, Andreas; Jansson, Kaj; Prokofiev, Alexander V.; Eronen, Tommi; Gorelov, Dimitri; Jokinen, Ari; Kankainen, Anu; Moore, Iain D.; Penttilä, Heikki; Rinta-Antila, Sami

2018-03-01

Data on fission yields and isomeric yield ratios (IYR) are tools to study the fission process, in particular the generation of angular momentum. We use the IGISOL facility with the Penning trap JYFLTRAP in Jyväskylä, Finland, for such measurements on 232Th and natU targets. Previously published fission yield data from IGISOL concern the 232Th(p,f) and 238U(p,f) reactions at 25 and 50 MeV. Recently, a neutron source, using the Be(p,n) reaction, has been developed, installed and tested. We summarize the results for (p,f) focusing on the first measurement of IYR by direct ion counting. We also present first results for IYR and relative yields for Sn and Sb isotopes in the 128-133 mass range from natU(n,f) based on γ-spectrometry. We find a staggering behaviour in the cumulative yields for Sn and a shift in the independent fission yields for Sb as compared to current evaluations. Plans for the future experimental program on fission yields and IYR measurements are discussed.

Synthesis of crystalline Ce-activated garnet phosphor powders and technique to characterize their scintillation light yield

NASA Astrophysics Data System (ADS)

Gordienko, E.; Fedorov, A.; Radiuk, E.; Mechinsky, V.; Dosovitskiy, G.; Vashchenkova, E.; Kuznetsova, D.; Retivov, V.; Dosovitskiy, A.; Korjik, M.; Sandu, R.

2018-04-01

This work reports on a process of preparation of garnet phosphor powders and a technique for light yield evaluation of strongly light scattering samples. Powders of scintillation compounds could be used as individual materials or as samples for express tests of scintillation properties. However, estimation of their light yield (LY) is complicated by strong light scattering of this kind of materials. Ce3+-activated yttrium-aluminum and gallium-gadolinium-aluminum garnet phosphor powders, Y3Al5O12 (YAG:Ce) and Gd3Ga3Al2O12 (GGAG:Ce), were obtained using a modified coprecipitation technique. Ga tends to residue in mother liquor in ammonia media, but the modification allows to avoid the loss of components. We propose an approach for sample preparation and LY measurement setup with alpha particles excitation, allowing to decrease light scattering influence and to estimate a light yield of powder samples. This approach is used to evaluate the obtained powders.

Climate change impacts on crop yield in the Euro-Mediterranean region

NASA Astrophysics Data System (ADS)

Toreti, Andrea; Ceglar, Andrej; Dentener, Frank; Niemeyer, Stefan; Dosio, Alessandro; Fumagalli, Davide

2017-04-01

Agriculture is strongly influenced by climate variability, climate extremes and climate changes. Recent studies on past decades have identified and analysed the effects of climate variability and extremes on crop yields in the Euro-Mediterranean region. As these effects could be amplified in a changing climate context, it is essential to analyse available climate projections and investigate the possible impacts on European agriculture in terms of crop yield. In this study, five model runs from the Euro-CORDEX initiative under two scenarios (RCP4.5 and RCP8.5) have been used. Climate model data have been bias corrected and then used to feed a mechanistic crop growth model. The crop model has been run under different settings to better sample the intrinsic uncertainties. Among the main results, it is worth to report a weak but significant and spatially homogeneous increase in potential wheat yield at mid-century (under a CO2 fertilisation effect scenario). While more complex changes seem to characterise potential maize yield, with large areas in the region showing a weak-to-moderate decrease.

Hydrogen bonding and interparticle forces in platelet alpha-Al2O3 dispersions: yield stress and zeta potential.

PubMed

Khoo, Kay-Sen; Teh, E-Jen; Leong, Yee-Kwong; Ong, Ban Choon

2009-04-09

Adsorbed phosphate on smooth platelet alpha-Al2O3 particles at saturation surface coverage gives rise to strong interparticle attractive forces in dispersion. The maximum yield stress at the point of zero charge was increased by 2-fold. This was attributed to a high density of intermolecular hydrogen bonding between the adsorbed phosphate layers of the interacting particles. Adsorbed citrate at saturation surface coverage, however, reduced the maximum yield stress by 50%. It adsorbed to form a very effective steric barrier as intramolecular hydrogen bonding between -OH and the free terminal carboxylic group prevented strong interactions with other adsorbed citrate molecules residing on the second interacting particle. This steric barrier kept the interacting platelet particles further apart, thereby weakening the van der Waals attraction. The platelet alpha-Al2O3 dispersions were flocculated at all pH level. These dispersions displayed a maximum yield stress at the point of zero zeta potential at the pH approximately 8.0. They also obeyed the yield stress-DLVO force model as characterized by a linear decrease in the yield stress with the square of the zeta potential.

Slope Controls Grain Yield and Climatic Yield in Mountainous Yunnan province, China

NASA Astrophysics Data System (ADS)

Duan, X.; Rong, L.; Gu, Z.; Feng, D.

2017-12-01

Mountainous regions are increasingly vulnerable to food insecurity because of limited arable land, growing population pressure, and climate change. Development of sustainable mountain agriculture will require an increased understanding of the effects of environmental factors on grain and climatic yields. The objective of this study was to explore the relationships between actual grain yield, climatic yield, and environmental factors in a mountainous region in China. We collected data on the average grain yield per unit area in 119 counties in Yunnan province from 1985 to 2012, and chose 17 environmental factors for the same period. Our results showed that actual grain yield ranged from 1.43 to 6.92 t·ha-1, and the climatic yield ranged from -0.15 to -0.01 t·ha-1. Lower climatic yield but higher grain yield was generally found in central areas and at lower slopes and elevations in the western and southwestern counties of Yunnan province. Higher climatic yield but lower grain yield were found in northwestern parts of Yunnan province on steep slopes. Annual precipation and temperature had a weak influence on the climatic yield. Slope explained 44.62 and 26.29% of the variation in grain yield and climatic yield. The effects of topography on grain and climatic yields were greater than climatic factors. Slope was the most important environmental variable for the variability in climatic and grain yields in the mountainous Yunnan province due to the highly heterogeneous topographic conditions. Conversion of slopes to terraces in areas with higher climatic yields is an effective way to maintain grain production in response to climate variability. Additionally, soil amendments and soil and water conservation measures should be considered to maintain soil fertility and aid in sustainable development in central areas, and in counties at lower slopes and elevations in western and southwestern Yunnan province.

Impacts of drought on grape yields in Western Cape, South Africa

NASA Astrophysics Data System (ADS)

Araujo, Julio A.; Abiodun, Babatunde J.; Crespo, Olivier

2016-01-01

Droughts remain a threat to grape yields in South Africa. Previous studies on the impacts of climate on grape yield in the country have focussed on the impact of rainfall and temperature separately; meanwhile, grape yields are affected by drought, which is a combination of rainfall and temperature influences. The present study investigates the impacts of drought on grape yields in the Western Cape (South Africa) at district and farm scales. The study used a new drought index that is based on simple water balance (Standardized Precipitation Evapotranspiration Index; hereafter, SPEI) to identify drought events and used a correlation analysis to identify the relationship between drought and grape yields. A crop simulation model (Agricultural Production Systems sIMulator, APSIM) was applied at the farm scale to investigate the role of irrigation in mitigating the impacts of drought on grape yield. The model gives a realistic simulation of grape yields. The Western Cape has experienced a series of severe droughts in the past few decades. The severe droughts occurred when a decrease in rainfall occurred simultaneously with an increase in temperature. El Niño Southern Oscillation (ENSO) appears to be an important driver of drought severity in the Western Cape, because most of the severe droughts occurred in El Niño years. At the district scale, the correlation between drought index and grape yield is weak ( r≈-0.5), but at the farm scale, it is strong ( r≈-0.9). This suggests that many farmers are able to mitigate the impacts of drought on grape yields through irrigation management. At the farm scale, where the impact of drought on grape yields is high, poor yield years coincide with moderate or severe drought periods. The APSIM simulation, which gives a realistic simulation of grape yields at the farm scale, suggests that grape yields become more sensitive to spring and summer droughts in the absence of irrigation. Results of this study may guide decision-making on

Construction of exchange-correlation functionals through interpolation between the non-interacting and the strong-correlation limit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Yongxi; Ernzerhof, Matthias, E-mail: Matthias.Ernzerhof@UMontreal.ca; Bahmann, Hilke

Drawing on the adiabatic connection of density functional theory, exchange-correlation functionals of Kohn-Sham density functional theory are constructed which interpolate between the extreme limits of the electron-electron interaction strength. The first limit is the non-interacting one, where there is only exchange. The second limit is the strong correlated one, characterized as the minimum of the electron-electron repulsion energy. The exchange-correlation energy in the strong-correlation limit is approximated through a model for the exchange-correlation hole that is referred to as nonlocal-radius model [L. O. Wagner and P. Gori-Giorgi, Phys. Rev. A 90, 052512 (2014)]. Using the non-interacting and strong-correlated extremes, variousmore » interpolation schemes are presented that yield new approximations to the adiabatic connection and thus to the exchange-correlation energy. Some of them rely on empiricism while others do not. Several of the proposed approximations yield the exact exchange-correlation energy for one-electron systems where local and semi-local approximations often fail badly. Other proposed approximations generalize existing global hybrids by using a fraction of the exchange-correlation energy in the strong-correlation limit to replace an equal fraction of the semi-local approximation to the exchange-correlation energy in the strong-correlation limit. The performance of the proposed approximations is evaluated for molecular atomization energies, total atomic energies, and ionization potentials.« less

Synergistic interactions of ecosystem services: florivorous pest control boosts crop yield increase through insect pollination.

PubMed

Sutter, Louis; Albrecht, Matthias

2016-02-10

Insect pollination and pest control are pivotal functions sustaining global food production. However, they have mostly been studied in isolation and how they interactively shape crop yield remains largely unexplored. Using controlled field experiments, we found strong synergistic effects of insect pollination and simulated pest control on yield quantity and quality. Their joint effect increased yield by 23%, with synergistic effects contributing 10%, while their single contributions were 7% and 6%, respectively. The potential economic benefit for a farmer from the synergistic effects (12%) was 1.8 times greater than their individual contributions (7% each). We show that the principal underlying mechanism was a pronounced pest-induced reduction in flower lifetime, resulting in a strong reduction in the number of pollinator visits a flower receives during its lifetime. Our findings highlight the importance of non-additive interactions among ecosystem services (ES) when valuating, mapping or predicting them and reveal fundamental implications for ecosystem management and policy aimed at maximizing ES for sustainable agriculture. © 2016 The Author(s).

Musician's dystonia is highly task specific: no strong evidence for everyday fine motor deficits in patients.

PubMed

Hofmann, Aurélie; Grossbach, Michael; Baur, Volker; Hermsdörfer, Joachim; Altenmüller, Eckart

2015-03-01

1) To examine the fine motor skills used everyday by patients suffering from musician's dystonia (MD) in the upper limb in order to verify whether MD is task-specific; and 2) to compare the affected and non-affected hands of MD musicians vs healthy musicians in performance of these tasks in order to clarify whether dystonic symptoms can be found in the non-affected side of MD patients. MD is typically considered to be focal and task specific, but patients often report impairment in everyday life activities. Furthermore, in the course of MD, about 15% of patients complain of dystonic symptoms in other parts of the body. Twenty-seven musicians affected by MD and 27 healthy musicians were studied using 1) the Motor Performance Test Series, 2) a kinematic analysis of handwriting, and 3) an assessment of the grip force regulation while lifting and moving a manipulandum. Patients performed most fine motor tasks without any evidence of a deficit. Exclusively in the handwriting tasks (2), they exhibited fewer frequencies of the written trace and a prolonged overall writing time. MD is highly task specific and does not strongly affect other motor skills. The subtle deficits in handwriting may be explained as a consequence of a general psychological disposition rather than as compensatory mechanisms to avoid the appearance of dystonic symptoms. Furthermore, we did not find signs of multifocal motor deficits in the unaffected hands of MD patients.

Strong contribution of immigration to local population regulation: evidence from a migratory passerine.

PubMed

Schaub, Michael; Jakober, Hans; Stauber, Wolfgang

2013-08-01

A mechanistic understanding of the dynamics of populations requires knowledge about the variation of the underlying demographic rates and about the reasons for their variability. In geographically open populations, immigration is often necessary to prevent declines, but little is known about whether immigration can contribute to its regulation. We studied the dynamics of a Red-backed Shrike population (Lanius collurio) over 36 years in Germany with a Bayesian integrated population model. We estimated mean and temporal variability of population sizes, productivity, apparent survival, and immigration. We assessed how strongly the demographic rates were correlated with population growth to understand the demographic reasons of population change and how strongly the demographic rates were correlated with population size to identify possible density-dependent mechanisms. The shrike population varied between 35 and 74 breeding pairs but did not show a significant trend in population size over time (growth rate 1.002 +/- 0.001 [mean +/- SD]). Apparent survival of females (juveniles 0.06 +/- 0.01; adults 0.37 +/- 0.03) was lower than that of males (juveniles 0.10 +/- 0.01; adults 0.44 +/- 0.02). Immigration rates were substantial and higher in females (0.56 +/- 0.02) than in males (0.43 +/- 0.02), and average productivity was 2.76 +/- 0.14. Without immigration, the Red-backed Shrike population would have declined strongly. Immigration was the strongest driver for the number of females while local recruitment was the most important driver for the number of males. Immigration of both sexes and productivity, but not local recruitment and survival, were subject to density dependence. Density-dependent productivity was not effectively regulating the local population but may have contributed to regulate shrike populations at larger spatial scales. These findings suggest that immigration is not only an important component to prevent a geographically open population from decline

Climate Change and Its Impact on the Yield of Major Food Crops: Evidence from Pakistan

PubMed Central

Ali, Sajjad; Liu, Ying; Ishaq, Muhammad; Shah, Tariq; Abdullah; Ilyas, Aasir; Din, Izhar Ud

2017-01-01

Pakistan is vulnerable to climate change, and extreme climatic conditions are threatening food security. This study examines the effects of climate change (e.g., maximum temperature, minimum temperature, rainfall, relative humidity, and the sunshine) on the major crops of Pakistan (e.g., wheat, rice, maize, and sugarcane). The methods of feasible generalized least square (FGLS) and heteroscedasticity and autocorrelation (HAC) consistent standard error were employed using time series data for the period 1989 to 2015. The results of the study reveal that maximum temperature adversely affects wheat production, while the effect of minimum temperature is positive and significant for all crops. Rainfall effect towards the yield of a selected crop is negative, except for wheat. To cope with and mitigate the adverse effects of climate change, there is a need for the development of heat- and drought-resistant high-yielding varieties to ensure food security in the country. PMID:28538704

Climate Change and Its Impact on the Yield of Major Food Crops: Evidence from Pakistan.

PubMed

Ali, Sajjad; Liu, Ying; Ishaq, Muhammad; Shah, Tariq; Abdullah; Ilyas, Aasir; Din, Izhar Ud

2017-05-24

Pakistan is vulnerable to climate change, and extreme climatic conditions are threatening food security. This study examines the effects of climate change (e.g., maximum temperature, minimum temperature, rainfall, relative humidity, and the sunshine) on the major crops of Pakistan (e.g., wheat, rice, maize, and sugarcane). The methods of feasible generalized least square (FGLS) and heteroscedasticity and autocorrelation (HAC) consistent standard error were employed using time series data for the period 1989 to 2015. The results of the study reveal that maximum temperature adversely affects wheat production, while the effect of minimum temperature is positive and significant for all crops. Rainfall effect towards the yield of a selected crop is negative, except for wheat. To cope with and mitigate the adverse effects of climate change, there is a need for the development of heat- and drought-resistant high-yielding varieties to ensure food security in the country.

Genetic parameters for yearling weight, carcass traits, and primal-cut yields of Hanwoo cattle.

PubMed

Choi, T J; Alam, M; Cho, C I; Lee, J G; Park, B; Kim, S; Koo, Y; Roh, S H

2015-04-01

Genetic parameters associated with yearling weight, carcass traits, and primal-cut yields of male Hanwoo cattle were investigated using univariate and bivariate animal models. The mean yearling weight (YWT), carcass weight (CWT), longissimus muscle area (LMA), backfat thickness (BFT), and marbling score (MS) were 352.47 ± 0.40 kg, 337.39 ± 0.64 kg, 78.28 ± 0.13 cm2, 8.45 ± 0.05 mm, and 3.25 ± 0.03, respectively. Total primal-cut yield (TPC) was 78.95 ± 0.10% of CWT, of which 42.3% was contributed by the forequarters (chuck, CHK; shoulder, SLD; ribs, RIB; and brisket and flank, BAF). Loins, top round (TRND), and round (RND) were associated with yields of 13.57%, 5.45 ± 0.01%, and 8.87 ± 0.02%, respectively. The largest cut studied was ribs (15.67 ± 0.03%). The estimated heritabilities (h2) of YWT, CWT, LMA, BFT, and MS were 0.18 ± 0.02, 0.29 ± 0.04, 0.38 ± 0.05, 0.45 ± 0.05, and 0.62 ± 0.07, respectively. Shoulder yield was highly heritable in Hanwoo steers (0.83 ± 0.13), followed by the yields of round (0.66 ± 0.12), striploin (0.64 ± 0.12), top round (0.62 ± 0.12), sirloin (0.60 ± 0.12), and total primal-cut yield (0.52 ± 0.11). The h2 values of CHK, BAF, RIB, and tenderloin (TLN) ranged from 0.19 ± 0.09 to 0.41 ± 0.11. Generally, the genetic CV was low for most traits (2.33%-6.15%), except for CHK, BFT, and MS. The genetic correlation (rg) was strong between YWT and CWT (0.77 ± 0.06). The greatest positive and negative rg among carcass traits were those between LMA and CWT (0.52 ± 0.08) and between LMA and BFT (-0.30 ± 0.09), respectively. The correlation between CHK and SLD (0.81 ± 0.14), and those between SLD, TLN, TRND, and RND, were mostly strong (0.77-0.87), but the rg between RIB and other traits were strongly negative. The TPC yield showed moderate to high rg with most primal cuts. The YWT, CWT, and LMA correlated notably with CHK, SLD, and loin yields, especially LMA. However, BFT and MS were negatively correlated with many

Quadratic Fermi node in a 3D strongly correlated semimetal

PubMed Central

Kondo, Takeshi; Nakayama, M.; Chen, R.; Ishikawa, J. J.; Moon, E.-G.; Yamamoto, T.; Ota, Y.; Malaeb, W.; Kanai, H.; Nakashima, Y.; Ishida, Y.; Yoshida, R.; Yamamoto, H.; Matsunami, M.; Kimura, S.; Inami, N.; Ono, K.; Kumigashira, H.; Nakatsuji, S.; Balents, L.; Shin, S.

2015-01-01

Strong spin–orbit coupling fosters exotic electronic states such as topological insulators and superconductors, but the combination of strong spin–orbit and strong electron–electron interactions is just beginning to be understood. Central to this emerging area are the 5d transition metal iridium oxides. Here, in the pyrochlore iridate Pr2Ir2O7, we identify a non-trivial state with a single-point Fermi node protected by cubic and time-reversal symmetries, using a combination of angle-resolved photoemission spectroscopy and first-principles calculations. Owing to its quadratic dispersion, the unique coincidence of four degenerate states at the Fermi energy, and strong Coulomb interactions, non-Fermi liquid behaviour is predicted, for which we observe some evidence. Our discovery implies that Pr2Ir2O7 is a parent state that can be manipulated to produce other strongly correlated topological phases, such as topological Mott insulator, Weyl semimetal, and quantum spin and anomalous Hall states. PMID:26640114

Quadratic Fermi node in a 3D strongly correlated semimetal

DOE PAGES

Kondo, Takeshi; Nakayama, M.; Chen, R.; ...

2015-12-07

We report that strong spin–orbit coupling fosters exotic electronic states such as topological insulators and superconductors, but the combination of strong spin–orbit and strong electron–electron interactions is just beginning to be understood. Central to this emerging area are the 5d transition metal iridium oxides. Here, in the pyrochlore iridate Pr 2Ir 2O 7, we identify a non-trivial state with a single-point Fermi node protected by cubic and time-reversal symmetries, using a combination of angle-resolved photoemission spectroscopy and first-principles calculations. Owing to its quadratic dispersion, the unique coincidence of four degenerate states at the Fermi energy, and strong Coulomb interactions, non-Fermimore » liquid behaviour is predicted, for which we observe some evidence. Lastly, our discovery implies that Pr 2Ir 2O 7 is a parent state that can be manipulated to produce other strongly correlated topological phases, such as topological Mott insulator, Weyl semimetal, and quantum spin and anomalous Hall states.« less

MULTI-KEV X-RAY YIELDS FROM HIGH-Z GAS TARGETS FIELDED AT OMEGA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kane, J O; Fournier, K B; May, M J

2010-11-04

The authors report on modeling of x-ray yield from gas-filled targets shot at the OMEGA laser facility. The OMEGA targets were 1.8 mm long, 1.95 mm in diameter Be cans filled with either a 50:50 Ar:Xe mixture, pure Ar, pure Kr or pure Xe at {approx} 1 atm. The OMEGA experiments heated the gas with 20 kJ of 3{omega} ({approx} 350 nm) laser energy delivered in a 1 ns square pulse. the emitted x-ray flux was monitored with the x-ray diode based DANTE instruments in the sub-keV range. Two-dimensional x-ray images (for energies 3-5 keV) of the targets were recordedmore » with gated x-ray detectors. The x-ray spectra were recorded with the HENWAY crystal spectrometer at OMEGA. Predictions are 2D r-z cylindrical with DCA NLTE atomic physics. Models generally: (1) underpredict the Xe L-shell yields; (2) overpredict the Ar K-shell yields; (3) correctly predict the Xe thermal yields; and (4) greatly underpredict the Ar thermal yields. However, there are spreads within the data, e.g. the DMX Ar K-shell yields are correctly predicted. The predicted thermal yields show strong angular dependence.« less

Charge Yield at Low Electric Fields: Considerations for Bipolar Integrated Circuits

NASA Technical Reports Server (NTRS)

Johnston, A. H.; Swimm, R. T.; Thorbourn, D. O.

2013-01-01

A significant reduction in total dose damage is observed when bipolar integrated circuits are irradiated at low temperature. This can be partially explained by the Onsager theory of recombination, which predicts a strong temperature dependence for charge yield under low-field conditions. Reduced damage occurs for biased as well as unbiased devices because the weak fringing field in thick bipolar oxides only affects charge yield near the Si/SiO2 interface, a relatively small fraction of the total oxide thickness. Lowering the temperature of bipolar ICs - either continuously, or for time periods when they are exposed to high radiation levels - provides an additional degree of freedom to improve total dose performance of bipolar circuits, particularly in space applications.

Overexpression of an Arabidopsis thaliana galactinol synthase gene improves drought tolerance in transgenic rice and increased grain yield in the field.

PubMed

Selvaraj, Michael Gomez; Ishizaki, Takuma; Valencia, Milton; Ogawa, Satoshi; Dedicova, Beata; Ogata, Takuya; Yoshiwara, Kyouko; Maruyama, Kyonoshin; Kusano, Miyako; Saito, Kazuki; Takahashi, Fuminori; Shinozaki, Kazuo; Nakashima, Kazuo; Ishitani, Manabu

2017-11-01

Drought stress has often caused significant decreases in crop production which could be associated with global warming. Enhancing drought tolerance without a grain yield penalty has been a great challenge in crop improvement. Here, we report the Arabidopsis thaliana galactinol synthase 2 gene (AtGolS2) was able to confer drought tolerance and increase grain yield in two different rice (Oryza sativa) genotypes under dry field conditions. The developed transgenic lines expressing AtGolS2 under the control of the constitutive maize ubiquitin promoter (Ubi:AtGolS2) also had higher levels of galactinol than the non-transgenic control. The increased grain yield of the transgenic rice under drought conditions was related to a higher number of panicles, grain fertility and biomass. Extensive confined field trials using Ubi:AtGolS2 transgenic lines in Curinga, tropical japonica and NERICA4, interspecific hybrid across two different seasons and environments revealed the verified lines have the proven field drought tolerance of the Ubi:AtGolS2 transgenic rice. The amended drought tolerance was associated with higher relative water content of leaves, higher photosynthesis activity, lesser reduction in plant growth and faster recovering ability. Collectively, our results provide strong evidence that AtGolS2 is a useful biotechnological tool to reduce grain yield losses in rice beyond genetic differences under field drought stress. © 2017 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Strong modification of photoluminescence in erbium-doped porous silicon microcavities

NASA Astrophysics Data System (ADS)

Zhou, Y.; Snow, P. A.; Russell, P. St. J.

2000-10-01

A microcavity composed of porous silicon multilayer mirrors was electrochemically etched and doped with erbium. Measurements of the reflectivity and photoluminescence spectra are presented. Thermal processing under a nitrogen atmosphere optically activated the erbium ions. Photopumping yielded room temperature emission around 1.54 μm from the erbium-doped samples with the emitted light strongly modified by the microcavity structure. Emission spectra with a peak at 1.536 μm had a full width at half maximum of ˜6 nm.

Identification of Crowding Stress Tolerance Co-Expression Networks Involved in Sweet Corn Yield

PubMed Central

Choe, Eunsoo; Drnevich, Jenny; Williams, Martin M.

2016-01-01

Tolerance to crowding stress has played a crucial role in improving agronomic productivity in field corn; however, commercial sweet corn hybrids vary greatly in crowding stress tolerance. The objectives were to 1) explore transcriptional changes among sweet corn hybrids with differential yield under crowding stress, 2) identify relationships between phenotypic responses and gene expression patterns, and 3) identify groups of genes associated with yield and crowding stress tolerance. Under conditions of crowding stress, three high-yielding and three low-yielding sweet corn hybrids were grouped for transcriptional and phenotypic analyses. Transcriptional analyses identified from 372 to 859 common differentially expressed genes (DEGs) for each hybrid. Large gene expression pattern variation among hybrids and only 26 common DEGs across all hybrid comparisons were identified, suggesting each hybrid has a unique response to crowding stress. Over-represented biological functions of DEGs also differed among hybrids. Strong correlation was observed between: 1) modules with up-regulation in high-yielding hybrids and yield traits, and 2) modules with up-regulation in low-yielding hybrids and plant/ear traits. Modules linked with yield traits may be important crowding stress response mechanisms influencing crop yield. Functional analysis of the modules and common DEGs identified candidate crowding stress tolerant processes in photosynthesis, glycolysis, cell wall, carbohydrate/nitrogen metabolic process, chromatin, and transcription regulation. Moreover, these biological functions were greatly inter-connected, indicating the importance of improving the mechanisms as a network. PMID:26796516

Evidence for Patchy Sediment Underthrusting and a Strong, Drained Outer Accretionary Wedge in Central Cascadia: Implications for Dynamic Slip Conditions

NASA Astrophysics Data System (ADS)

Tobin, H. J.; Webb, S. I.

2017-12-01

The central Cascadia subduction zone forearc in the region offshore Washington, where a hot, young incoming plate is covered by a 2-3 km thick sedimentary sequence, features a wide, very narrowly-tapered outer accretionary wedge composed of landward vergent thrust sheets. Longstanding questions for this region include the position and host-rock environment of the plate boundary décollement fault, the thickness of sedimentary strata underthrust beneath the wedge with the downgoing plate, and the effective stress or pore fluid pressure condition in the wedge and along its base. We have analyzed nine multichannel seismic lines of the 2012 COAST multi-channel seismic reflection survey using both time- and depth- migrated seismic sections for structural interpretation. Results show that there is evidence for two parallel décollement levels, with up to 200 - 500 meters thickness of a mostly-underthrust sequence in places, but which is absent entirely in others. This patchy distribution is mapped and related to features of the overlying wedge structure. We also analyzed the seismic interval velocity distribution produced during pre-stack depth migration imaging, and used it to compute estimated porosity, pore fluid pressure, and effective stress via empirical physical properties transforms. We find that the wedge shows evidence for at most only modest, localized excess pore pressure, and instead most of the wedge appears to be at near-hydrostatic, drained condition. Modest overpressure ratios of up to only 0.15 are detected, localized in the footwalls of thrust splays. We find no evidence for overpressure zones in the underthrust sequence below the upper décollement, in contrast to findings from several other wedges worldwide. Taken together, the accretionary wedge structure and apparent low pore pressure condition here is consistent with a mechanically strong wedge overlying a base that is very weak, at least transiently. By analogy with recent work from Sumatra

Experimental investigation of strong-field-ionization theories for laser fields from visible to midinfrared frequencies

NASA Astrophysics Data System (ADS)

Lai, Yu Hang; Xu, Junliang; Szafruga, Urszula B.; Talbert, Bradford K.; Gong, Xiaowei; Zhang, Kaikai; Fuest, Harald; Kling, Matthias F.; Blaga, Cosmin I.; Agostini, Pierre; DiMauro, Louis F.

2017-12-01

Strong-field-ionization yield versus intensity is investigated for various atomic targets (Ne, Ar, Kr, Xe, Na, K, Zn, and Mg) and light polarization from visible to mid-infrared (0.4-4 μ m ), from multiphoton to tunneling regimes. The experimental findings (normalized yield vs intensity, ratio of circular to linear polarization and saturation intensities) are compared to the theoretical models of Perelomov-Popov-Terent'ev (PPT) and Ammosov-Delone-Krainov (ADK). While PPT is generally satisfactory, ADK validity is found, as expected, to be much more limited.

Chemo-selective high yield microwave assisted reaction turns cellulose to green chemicals.

PubMed

Hassanzadeh, Salman; Aminlashgari, Nina; Hakkarainen, Minna

2014-11-04

Exceptionally high cellulose liquefaction yields, up to 87% as calculated from the amount of solid residue, were obtained under mild conditions by utilizing the synergistic effect of microwave radiation and acid catalysis. The effect of processing conditions on degradation products was fingerprinted by rapid laser desorption ionization-mass spectrometry (LDI-MS) method. The reaction was chemo-tunable, enabling production of glucose (Glc) or levulinic acid (LeA) at significantly high selectivity and yields, the relative molar yields being up to 50 and 69%, respectively. A turning point from pure depolymerization to glucose to further degradation to levulinic acid and formic acid was observed at approximately 50% liquefaction or above 140 °C. This was accompanied by the formation of small amounts of solid spherical carbonized residues. The reaction was monitored by multiple analytical techniques. The high yields were connected to the ability of the process to break the strong secondary interactions in cellulose. The developed method has great potential for future production of green platform chemicals. Copyright © 2014 Elsevier Ltd. All rights reserved.

Functional group diversity of bee pollinators increases crop yield

PubMed Central

Hoehn, Patrick; Tscharntke, Teja; Tylianakis, Jason M; Steffan-Dewenter, Ingolf

2008-01-01

Niche complementarity is a commonly invoked mechanism underlying the positive relationship between biodiversity and ecosystem functioning, but little empirical evidence exists for complementarity among pollinator species. This study related differences in three functional traits of pollinating bees (flower height preference, daily time of flower visitation and within-flower behaviour) to the seed set of the obligate cross-pollinated pumpkin Cucurbita moschata Duch. ex Poir. across a land-use intensity gradient from tropical rainforest and agroforests to grassland in Indonesia. Bee richness and abundance changed with habitat variables and we used this natural variation to test whether complementary resource use by the diverse pollinator community enhanced final yield. We found that pollinator diversity, but not abundance, was positively related to seed set of pumpkins. Bees showed species-specific spatial and temporal variation in flower visitation traits and within-flower behaviour, allowing for classification into functional guilds. Diversity of functional groups explained even more of the variance in seed set (r2=45%) than did species richness (r2=32%) highlighting the role of functional complementarity. Even though we do not provide experimental, but rather correlative evidence, we can link spatial and temporal complementarity in highly diverse pollinator communities to pollination success in the field, leading to enhanced crop yield without any managed honeybees. PMID:18595841

Yielding in colloidal gels due to nonlinear microstructure bending mechanics.

PubMed

Furst, Eric M; Pantina, John P

2007-05-01

We report measurements of the nonlinear micromechanics of strongly flocculated model colloidal aggregates. Linear aggregates directly assembled using laser tweezers are subjected to bending loads until a critical bending moment is reached, which is identified by a stictionlike rearrangement of a single colloidal bond. This nanoscale phenomenon provides a quantitative basis for understanding the macroscopic shear yield stresses of strongly flocculated polystyrene latex gels, based on the maximum bending moment exceeding the critical moment of the constituent colloidal bonds of the gel microstructure. These mechanics are consistent with the local bending moment overcoming the static friction force between neighboring adhesive particles. This results in a direct relationship between the rheology of these gels and the boundary friction between Brownian particles.

Spectral reflectance indices as a selection criterion for yield improvement in wheat

NASA Astrophysics Data System (ADS)

Babar, Md. Ali

2005-11-01

Scope and methods of study. Yield in wheat ( Triticum aestivum L.) is a complex trait and influenced by many environmental factors, and yield improvement is a daunting task for wheat breeders. Spectral reflectance indices (SRIs) have been used to study different physiological traits in wheat. SRIs have the potential to differentiate genotypes for grain yield. SRIs strongly associated with grain yield can be used to achieve effective genetic gain in wheat under different environments. Three experiments (15 adapted genotypes, 25 and 36 random sister lines derived from two different crosses) under irrigated conditions, and three experiments (each with 30 advanced genotypes) under water-limited conditions were conducted in three successive years in Northwest Mexico at the CIMMYT (International Maize and wheat Improvement Center) experimental station. SRIs and different agronomic data were collected for three years, and biomass was harvested for two years. Phenotypic and genetic correlations between SRIs and grain yield, between SRIs and biomass, realized and broad sense heritability, direct and correlated selection responses for grain yield, and SRIs were calculated. Findings and conclusion. Seven SRIs were calculated, and three near infrared based indices (WI, NWI-1 and NWI-2) showed higher level of genetic and phenotypic correlations with grain yield, yield components and biomass than other SRIs (PRI, RNDVI, GNDVI, and SR) under both irrigated and water limiting environments. Moderate to high realized and broad sense heritability, and selection response were demonstrated by the three NIR based indices. High efficiency of correlated response for yield estimation was demonstrated by the three NIR based indices. The ratio between the correlated response to grain yield based on the three NIR based indices and direct selection response for grain yield was very close to one. The NIR based indices showed very high accuracy in selecting superior genotypes for grain yield

A Bayesian framework for knowledge attribution: evidence from semantic integration.

PubMed

Powell, Derek; Horne, Zachary; Pinillos, N Ángel; Holyoak, Keith J

2015-06-01

We propose a Bayesian framework for the attribution of knowledge, and apply this framework to generate novel predictions about knowledge attribution for different types of "Gettier cases", in which an agent is led to a justified true belief yet has made erroneous assumptions. We tested these predictions using a paradigm based on semantic integration. We coded the frequencies with which participants falsely recalled the word "thought" as "knew" (or a near synonym), yielding an implicit measure of conceptual activation. Our experiments confirmed the predictions of our Bayesian account of knowledge attribution across three experiments. We found that Gettier cases due to counterfeit objects were not treated as knowledge (Experiment 1), but those due to intentionally-replaced evidence were (Experiment 2). Our findings are not well explained by an alternative account focused only on luck, because accidentally-replaced evidence activated the knowledge concept more strongly than did similar false belief cases (Experiment 3). We observed a consistent pattern of results across a number of different vignettes that varied the quality and type of evidence available to agents, the relative stakes involved, and surface details of content. Accordingly, the present findings establish basic phenomena surrounding people's knowledge attributions in Gettier cases, and provide explanations of these phenomena within a Bayesian framework. Copyright © 2015 Elsevier B.V. All rights reserved.

Hemispheric Differences in Strong versus Weak Semantic Priming: Evidence from Event-Related Brain Potentials

ERIC Educational Resources Information Center

Frishkoff, Gwen A.

2007-01-01

Goals: Research with lateralized word presentation has suggested that strong ("close") and weak ("remote") semantic associates are processed differently in the left and right cerebral hemispheres [e.g., Beeman, M. j., & Chiarello, C. (1998). Complementary right- and left-hemisphere language comprehension. "Current Directions in Psychological…

Preliminary analysis of strong-motion recordings from the 28 September 2004 Parkfield, California earthquake

USGS Publications Warehouse

Shakal, A.; Graizer, V.; Huang, M.; Borcherdt, R.; Haddadi, H.; Lin, K.-W.; Stephens, C.; Roffers, P.

2005-01-01

The Parkfield 2004 earthquake yielded the most extensive set of strong-motion data in the near-source region of a magnitude 6 earthquake yet obtained. The recordings of acceleration and volumetric strain provide an unprecedented document of the near-source seismic radiation for a moderate earthquake. The spatial density of the measurements alon g the fault zone and in the linear arrays perpendicular to the fault is expected to provide an exceptional opportunity to develop improved models of the rupture process. The closely spaced measurements should help infer the temporal and spatial distribution of the rupture process at much higher resolution than previously possible. Preliminary analyses of the peak a cceleration data presented herein shows that the motions vary significantly along the rupture zone, from 0.13 g to more than 2.5 g, with a map of the values showing that the larger values are concentrated in three areas. Particle motions at the near-fault stations are consistent with bilateral rupture. Fault-normal pulses similar to those observed in recent strike-slip earthquakes are apparent at several of the stations. The attenuation of peak ground acceleration with distance is more rapid than that indicated by some standard relationships but adequately fits others. Evidence for directivity in the peak acceleration data is not strong. Several stations very near, or over, the rupturing fault recorded relatively low accelerations. These recordings may provide a quantitative basis to understand observations of low near-fault shaking damage that has been reported in other large strike-slip earthquak.

Opposing effects of different soil organic matter fractions on crop yields.

PubMed

Wood, Stephen A; Sokol, Noah; Bell, Colin W; Bradford, Mark A; Naeem, Shahid; Wallenstein, Matthew D; Palm, Cheryl A

2016-10-01

Soil organic matter is critical to sustainable agriculture because it provides nutrients to crops as it decomposes and increases nutrient- and water-holding capacity when built up. Fast- and slow-cycling fractions of soil organic matter can have different impacts on crop production because fast-cycling fractions rapidly release nutrients for short-term plant growth and slow-cycling fractions bind nutrients that mineralize slowly and build up water-holding capacity. We explored the controls on these fractions in a tropical agroecosystem and their relationship to crop yields. We performed physical fractionation of soil organic matter from 48 farms and plots in western Kenya. We found that fast-cycling, particulate organic matter was positively related to crop yields, but did not have a strong effect, while slower-cycling, mineral-associated organic matter was negatively related to yields. Our finding that slower-cycling organic matter was negatively related to yield points to a need to revise the view that stabilization of organic matter positively impacts food security. Our results support a new paradigm that different soil organic matter fractions are controlled by different mechanisms, potentially leading to different relationships with management outcomes, like crop yield. Effectively managing soils for sustainable agriculture requires quantifying the effects of specific organic matter fractions on these outcomes. © 2016 by the Ecological Society of America.

The yield and post-yield behavior of high-density polyethylene

NASA Technical Reports Server (NTRS)

Semeliss, M. A.; Wong, R.; Tuttle, M. E.

1990-01-01

An experimental and analytical evaluation was made of the yield and post-yield behavior of high-density polyethylene, a semi-crystalline thermoplastic. Polyethylene was selected for study because it is very inexpensive and readily available in the form of thin-walled tubes. Thin-walled tubular specimens were subjected to axial loads and internal pressures, such that the specimens were subjected to a known biaxial loading. A constant octahederal shear stress rate was imposed during all tests. The measured yield and post-yield behavior was compared with predictions based on both isotropic and anisotropic models. Of particular interest was whether inelastic behavior was sensitive to the hydrostatic stress level. The major achievements and conclusions reached are discussed.

The anomalous yield behavior of fused silica glass

NASA Astrophysics Data System (ADS)

Schill, W.; Heyden, S.; Conti, S.; Ortiz, M.

2018-04-01

We develop a critical-state model of fused silica plasticity on the basis of data mined from molecular dynamics (MD) calculations. The MD data is suggestive of an irreversible densification transition in volumetric compression resulting in permanent, or plastic, densification upon unloading. The MD data also reveals an evolution towards a critical state of constant volume under pressure-shear deformation. The trend towards constant volume is from above, when the glass is overconsolidated, or from below, when it is underconsolidated. We show that these characteristic behaviors are well-captured by a critical state model of plasticity, where the densification law for glass takes the place of the classical consolidation law of granular media and the locus of constant-volume states defines the critical-state line. A salient feature of the critical-state line of fused silica, as identified from the MD data, that renders its yield behavior anomalous is that it is strongly non-convex, owing to the existence of two well-differentiated phases at low and high pressures. We argue that this strong non-convexity of yield explains the patterning that is observed in molecular dynamics calculations of amorphous solids deforming in shear. We employ an explicit and exact rank-2 envelope construction to upscale the microscopic critical-state model to the macroscale. Remarkably, owing to the equilibrium constraint the resulting effective macroscopic behavior is still characterized by a non-convex critical-state line. Despite this lack of convexity, the effective macroscopic model is stable against microstructure formation and defines well-posed boundary-value problems.

Finding Strong Bridges and Strong Articulation Points in Linear Time

NASA Astrophysics Data System (ADS)

Italiano, Giuseppe F.; Laura, Luigi; Santaroni, Federico

Given a directed graph G, an edge is a strong bridge if its removal increases the number of strongly connected components of G. Similarly, we say that a vertex is a strong articulation point if its removal increases the number of strongly connected components of G. In this paper, we present linear-time algorithms for computing all the strong bridges and all the strong articulation points of directed graphs, solving an open problem posed in [2].

Understanding forensic expert evaluative evidence: A study of the perception of verbal expressions of the strength of evidence.

PubMed

Arscott, Eleanor; Morgan, Ruth; Meakin, Georgina; French, James

2017-05-01

Verbal expressions of evidential strength are routinely used when presenting forensic expert evaluative evidence. The degree to which these verbal expressions are interpreted uniformly among different individuals requires further empirical study. This study focussed on groups of individuals with different roles within the criminal justice system and individuals with varying degrees of expertise and knowledge. Three groups of individuals were identified: laypeople, legal professionals and those with some forensic or investigative knowledge. The participants in the study (n=230) were provided with a case summary to which a verbal expression of the strength of evidence was randomly assigned. Participants were subsequently invited to indicate their perception of the strength of the evidence on a scale that was provided. Generally, across the study groups, the trend was one of increased perceived strength of evidence as the intended strength of the verbal expression was increased, with some notable exceptions. In general, there was good concordance between the groups in the way the different expressions were perceived. It was found that participants performed poorly when it came to differentiating between expressions at the 'strong' end of the scale ('strong', 'very strong' and 'extremely strong'). The findings resonate with calls for validated and robust communication frameworks for evaluative opinions. Further empirical research in this area is warranted and that such research can represent an important contribution towards improving the communication and presentation of forensic evidence. Copyright © 2017 The Chartered Society of Forensic Sciences. Published by Elsevier B.V. All rights reserved.

Spatio-temporal response of maize yield to edaphic and meteorological conditions in a saline farmland

USDA-ARS?s Scientific Manuscript database

Spatio-temporal variability of crop production strongly depends on soil heterogeneity, meteorological conditions, and their interaction. Canopy reflectance can be used to describe crop status and yield spatial variability. The objectives of this work were to understand the spatio-temporal variabilit...

An adapted yield criterion for the evolution of subsequent yield surfaces

NASA Astrophysics Data System (ADS)

Küsters, N.; Brosius, A.

2017-09-01

In numerical analysis of sheet metal forming processes, the anisotropic material behaviour is often modelled with isotropic work hardening and an average Lankford coefficient. In contrast, experimental observations show an evolution of the Lankford coefficients, which can be associated with a yield surface change due to kinematic and distortional hardening. Commonly, extensive efforts are carried out to describe these phenomena. In this paper an isotropic material model based on the Yld2000-2d criterion is adapted with an evolving yield exponent in order to change the yield surface shape. The yield exponent is linked to the accumulative plastic strain. This change has the effect of a rotating yield surface normal. As the normal is directly related to the Lankford coefficient, the change can be used to model the evolution of the Lankford coefficient during yielding. The paper will focus on the numerical implementation of the adapted material model for the FE-code LS-Dyna, mpi-version R7.1.2-d. A recently introduced identification scheme [1] is used to obtain the parameters for the evolving yield surface and will be briefly described for the proposed model. The suitability for numerical analysis will be discussed for deep drawing processes in general. Efforts for material characterization and modelling will be compared to other common yield surface descriptions. Besides experimental efforts and achieved accuracy, the potential of flexibility in material models and the risk of ambiguity during identification are of major interest in this paper.

Further Evidence on the Weak and Strong Versions of the Screening Hypothesis in Greece.

ERIC Educational Resources Information Center

Lambropoulos, Haris S.

1992-01-01

Uses Greek data for 1981 and 1985 to test screening hypothesis by replicating method proposed by Psacharopoulos. Credentialism, or sheepskin effect of education, directly challenges human capital theory, which views education as a productivity augmenting process. Results do not support the strong version of the screening hypothesis and suggest…

Root Traits Enhancing Rice Grain Yield under Alternate Wetting and Drying Condition

PubMed Central

Sandhu, Nitika; Subedi, Sushil R.; Yadaw, Ram B.; Chaudhary, Bedanand; Prasai, Hari; Iftekharuddaula, Khandakar; Thanak, Tho; Thun, Vathany; Battan, Khushi R.; Ram, Mangat; Venkateshwarlu, Challa; Lopena, Vitaliano; Pablico, Paquito; Maturan, Paul C.; Cruz, Ma. Teresa Sta.; Raman, K. Anitha; Collard, Bertrand; Kumar, Arvind

2017-01-01

Reducing water requirements and lowering environmental footprints require attention to minimize risks to food security. The present study was conducted with the aim to identify appropriate root traits enhancing rice grain yield under alternate wetting and drying conditions (AWD) and identify stable, high-yielding genotypes better suited to the AWD across variable ecosystems. Advanced breeding lines, popular rice varieties and drought-tolerant lines were evaluated in a series of 23 experiments conducted in the Philippines, India, Bangladesh, Nepal and Cambodia in 2015 and 2016. A large variation in grain yield under AWD conditions enabled the selection of high-yielding and stable genotypes across locations, seasons and years. Water savings of 5.7–23.4% were achieved without significant yield penalty across different ecosystems. The mean grain yield of genotypes across locations ranged from 3.5 to 5.6 t/ha and the mean environment grain yields ranged from 3.7 (Cambodia) to 6.6 (India) t/ha. The best-fitting Finlay-Wilkinson regression model identified eight stable genotypes with mean grain yield of more than 5.0 t/ha across locations. Multidimensional preference analysis represented the strong association of root traits (nodal root number, root dry weight at 22 and 30 days after transplanting) with grain yield. The genotype IR14L253 outperformed in terms of root traits and high mean grain yield across seasons and six locations. The 1.0 t/ha yield advantage of IR14L253 over the popular cultivar IR64 under AWD shall encourage farmers to cultivate IR14L253 and also adopt AWD. The results suggest an important role of root architectural traits in term of more number of nodal roots and root dry weight at 10–20 cm depth on 22–30 days after transplanting (DAT) in providing yield stability and preventing yield reduction under AWD compared to continuous flooded conditions. Genotypes possessing increased number of nodal roots provided higher yield over IR64 as well as no

Strong monogamy of multiparty quantum entanglement for partially coherently superposed states

NASA Astrophysics Data System (ADS)

Kim, Jeong San

2016-03-01

We provide evidence for the validity of strong monogamy inequality of multiparty quantum entanglement using the square of convex-roof extended negativity (SCREN). We first consider a large class of multiqudit mixed states that are in a partially coherent superposition of a generalized W -class state and the vacuum, and provide some useful properties about this class of states. We show that monogamy inequality of multiqudit entanglement in terms of SCREN holds for this class of states. We further show that SCREN strong monogamy inequality of multiqudit entanglement also holds for this class of states. Thus SCREN is a good alternative for characterizing the monogamous and strongly monogamous properties of multiqudit entanglement.

Line-of-sight structure toward strong lensing galaxy clusters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bayliss, Matthew B.; Johnson, Traci; Sharon, Keren

2014-03-01

We present an analysis of the line-of-sight structure toward a sample of 10 strong lensing cluster cores. Structure is traced by groups that are identified spectroscopically in the redshift range, 0.1 ≤ z ≤ 0.9, and we measure the projected angular and comoving separations between each group and the primary strong lensing clusters in each corresponding line of sight. From these data we measure the distribution of projected angular separations between the primary strong lensing clusters and uncorrelated large-scale structure as traced by groups. We then compare the observed distribution of angular separations for our strong lensing selected lines ofmore » sight against the distribution of groups that is predicted for clusters lying along random lines of sight. There is clear evidence for an excess of structure along the line of sight at small angular separations (θ ≤ 6') along the strong lensing selected lines of sight, indicating that uncorrelated structure is a significant systematic that contributes to producing galaxy clusters with large cross sections for strong lensing. The prevalence of line-of-sight structure is one of several biases in strong lensing clusters that can potentially be folded into cosmological measurements using galaxy cluster samples. These results also have implications for current and future studies—such as the Hubble Space Telescope Frontier Fields—that make use of massive galaxy cluster lenses as precision cosmological telescopes; it is essential that the contribution of line-of-sight structure be carefully accounted for in the strong lens modeling of the cluster lenses.« less

Acid soil infertility effects on peanut yields and yield components

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blamey, F.P.C.

1983-01-01

The interpretation of soil amelioration experiments with peanuts is made difficult by the unpredictibility of the crop and by the many factors altered when ameliorating acid soils. The present study was conducted to investigate the effects of lime and gypsum applications on peanut kernel yield via the three first order yield components, pods per ha, kernels per pod, and kernel mass. On an acid medium sandy loam soil (typic Plinthustult), liming resulted in a highly significant kernel yield increase of 117% whereas gypsum applications were of no significant benefit. As indicated by path coefficient analysis, an increase in the numbermore » of pods per ha was markedly more important in increasing yield than an increase in either the number of kernels per pod or kernel mass. Furthermore, exch. Al was found to be particularly detrimental to pod number. It was postulated that poor peanut yields resulting from acid soil infertility were mainly due to the depressive effect of exch. Al on pod number. Exch. Ca appeared to play a secondary role by ameliorating the adverse effects of exch. Al.« less

There is not yet strong evidence that exercise regimens other than pelvic floor muscle training can reduce stress urinary incontinence in women: a systematic review.

PubMed

Bø, Kari; Herbert, Robert D

2013-09-01

What evidence is there for alternative exercises to specific pelvic floor muscle training for treatment of stress urinary incontinence in women? A systematic review was conducted with searches of PubMed and PEDro to January 2013. The quality of randomised trials was evaluated using the PEDro scale. Each type of exercise was classified as being in a Development Phase, Testing Phase, or Refinement and Dissemination Phase. Women with stress or mixed urinary incontinence with predominantly stress urinary incontinence. Exercise regimens other than pelvic floor muscle training. The primary outcome was urinary leakage. Seven randomised controlled trials were found: three on abdominal training, two on the Paula method, and two on Pilates exercise. The methodological quality score ranged between 4 and 8 with a mean of 5.7. There was no convincing evidence for the effect of these exercise regimens so they remain in the Testing Phase. Because no randomised trials were found for posture correction, breathing exercise, yoga, Tai Chi, and general fitness training, these were classified as being in the Development Phase. There is not yet strong evidence that alternative exercise regimens can reduce urinary leakage in women with stress urinary incontinence. Alternative exercise regimens should not yet be recommended for use in clinical practice for women with stress urinary incontinence. Copyright © 2013 Australian Physiotherapy Association. Published by .. All rights reserved.

Experimental evidence of impact ignition: 100-fold increase of neutron yield by impactor collision.

PubMed

Azechi, H; Sakaiya, T; Watari, T; Karasik, M; Saito, H; Ohtani, K; Takeda, K; Hosoda, H; Shiraga, H; Nakai, M; Shigemori, K; Fujioka, S; Murakami, M; Nagatomo, H; Johzaki, T; Gardner, J; Colombant, D G; Bates, J W; Velikovich, A L; Aglitskiy, Y; Weaver, J; Obenschain, S; Eliezer, S; Kodama, R; Norimatsu, T; Fujita, H; Mima, K; Kan, H

2009-06-12

We performed integrated experiments on impact ignition, in which a portion of a deuterated polystyrene (CD) shell was accelerated to about 600 km/s and was collided with precompressed CD fuel. The kinetic energy of the impactor was efficiently converted into thermal energy generating a temperature of about 1.6 keV. We achieved a two-order-of-magnitude increase in the neutron yield by optimizing the timing of the impact collision, demonstrating the high potential of impact ignition for fusion energy production.

Modelling climate change impacts on viticultural yield, phenology and stress conditions in Europe.

PubMed

Fraga, Helder; García de Cortázar Atauri, Iñaki; Malheiro, Aureliano C; Santos, João A

2016-11-01

Viticulture is a key socio-economic sector in Europe. Owing to the strong sensitivity of grapevines to atmospheric factors, climate change may represent an important challenge for this sector. This study analyses viticultural suitability, yield, phenology, and water and nitrogen stress indices in Europe, for present climates (1980-2005) and future (2041-2070) climate change scenarios (RCP4.5 and 8.5). The STICS crop model is coupled with climate, soil and terrain databases, also taking into account CO 2 physiological effects, and simulations are validated against observational data sets. A clear agreement between simulated and observed phenology, leaf area index, yield and water and nitrogen stress indices, including the spatial differences throughout Europe, is shown. The projected changes highlight an extension of the climatic suitability for grapevines up to 55°N, which may represent the emergence of new winemaking regions. Despite strong regional heterogeneity, mean phenological timings (budburst, flowering, veraison and harvest) are projected to undergo significant advancements (e.g. budburst/harvest can be >1 month earlier), with implications also in the corresponding phenophase intervals. Enhanced dryness throughout Europe is also projected, with severe water stress over several regions in southern regions (e.g. southern Iberia and Italy), locally reducing yield and leaf area. Increased atmospheric CO 2 partially offsets dryness effects, promoting yield and leaf area index increases in central/northern Europe. Future biomass changes may lead to modifications in nitrogen demands, with higher stress in northern/central Europe and weaker stress in southern Europe. These findings are critical decision support systems for stakeholders from the European winemaking sector. © 2016 John Wiley & Sons Ltd.

Sources of Pre-Analytical Variations in Yield of DNA Extracted from Blood Samples: Analysis of 50,000 DNA Samples in EPIC

PubMed Central

Caboux, Elodie; Lallemand, Christophe; Ferro, Gilles; Hémon, Bertrand; Mendy, Maimuna; Biessy, Carine; Sims, Matt; Wareham, Nick; Britten, Abigail; Boland, Anne; Hutchinson, Amy; Siddiq, Afshan; Vineis, Paolo; Riboli, Elio; Romieu, Isabelle; Rinaldi, Sabina; Gunter, Marc J.; Peeters, Petra H. M.; van der Schouw, Yvonne T.; Travis, Ruth; Bueno-de-Mesquita, H. Bas; Canzian, Federico; Sánchez, Maria-José; Skeie, Guri; Olsen, Karina Standahl; Lund, Eiliv; Bilbao, Roberto; Sala, Núria; Barricarte, Aurelio; Palli, Domenico; Navarro, Carmen; Panico, Salvatore; Redondo, Maria Luisa; Polidoro, Silvia; Dossus, Laure; Boutron-Ruault, Marie Christine; Clavel-Chapelon, Françoise; Trichopoulou, Antonia; Trichopoulos, Dimitrios; Lagiou, Pagona; Boeing, Heiner; Fisher, Eva; Tumino, Rosario; Agnoli, Claudia; Hainaut, Pierre

2012-01-01

The European Prospective Investigation into Cancer and nutrition (EPIC) is a long-term, multi-centric prospective study in Europe investigating the relationships between cancer and nutrition. This study has served as a basis for a number of Genome-Wide Association Studies (GWAS) and other types of genetic analyses. Over a period of 5 years, 52,256 EPIC DNA samples have been extracted using an automated DNA extraction platform. Here we have evaluated the pre-analytical factors affecting DNA yield, including anthropometric, epidemiological and technical factors such as center of subject recruitment, age, gender, body-mass index, disease case or control status, tobacco consumption, number of aliquots of buffy coat used for DNA extraction, extraction machine or procedure, DNA quantification method, degree of haemolysis and variations in the timing of sample processing. We show that the largest significant variations in DNA yield were observed with degree of haemolysis and with center of subject recruitment. Age, gender, body-mass index, cancer case or control status and tobacco consumption also significantly impacted DNA yield. Feedback from laboratories which have analyzed DNA with different SNP genotyping technologies demonstrate that the vast majority of samples (approximately 88%) performed adequately in different types of assays. To our knowledge this study is the largest to date to evaluate the sources of pre-analytical variations in DNA extracted from peripheral leucocytes. The results provide a strong evidence-based rationale for standardized recommendations on blood collection and processing protocols for large-scale genetic studies. PMID:22808065

The Measurement of Strong-Interaction Effects in High-Z Sigma Hyperonic Atoms.

NASA Astrophysics Data System (ADS)

Phillips, William Clarke

Strong-interaction effects have been observed in the X-ray spectra of atoms formed with Sigma ^- in lead and tungsten. In the experiment, performed at the Alternating Gradient Synchrotron of Brookhaven National Laboratory, negative kaons were brought to rest in a novel laminar target consisting of thin sheets of high-Z material in a liquid hydrogen bath. The geometry of the target was designed to optimize the production of high-Z Sigma^- atoms and the detection of their subsequent de-excitation X rays. A method of identifying the energetic pi^+ from the production reaction K^-+ p toSigma^- +pi^+ resulted in a factor of 15 improvement in the signal-to -noise ratio of the Sigma^- atom X-rays over that of previous experiments. The X-ray spectra were recorded by three high-resolution intrinsic Ge detectors and analyzed for shifts, broadenings, and yield reductions of the final X-ray transitions before absorption of the Sigma^- into the nucleus. A lineshape function which reflected the non-Gaussian response of the X-ray spectroscopy system was developed for this analysis. The results are(UNFORMATTED TABLE OR EQUATION FOLLOWS)eqalign {Sigma^- - W (10to9): varepsilon = 650 +/- 30 eV,&quadGamma = 380 +/- 70 eV,quad %Y = .98 +/- .04cr Sigma^- - Pb (10to9): varepsilon = 510 +/- 50 eV,&quadGamma = 290 +/- 140 eV, quad %Y = .53 +/- .04cr} (TABLE/EQUATION ENDS)where varepsilon = E_{rm meds} - E_{rm calc }, Gamma is the Lorentzian FWHM, and %Y is the ratio (measured yield)/(yield calculated with no strong interaction). Optical model calculations with a = (0.928 + i0.022) fm are able to reproduce all observed effects in the Sigma^--W spectra. Such calculations with a = (0.247 + i0.039) fm reproduce the observed shift and width of the (10to9) transition in Sigma^--Pb, but fail to reproduce the observed yield reduction. It is doubtful if the current status of the theory of Sigma ^--N interactions can explain this discrepancy.

World Health Organization recommendations are often strong based on low confidence in effect estimates.

PubMed

Alexander, Paul E; Bero, Lisa; Montori, Victor M; Brito, Juan Pablo; Stoltzfus, Rebecca; Djulbegovic, Benjamin; Neumann, Ignacio; Rave, Supriya; Guyatt, Gordon

2014-06-01

Expert guideline panelists are sometimes reluctant to offer weak/conditional/contingent recommendations. Grading of Recommendations Assessment, Development and Evaluation (GRADE) guidance warns against strong recommendations when confidence in effect estimates is low or very low, suggesting that such recommendations may seldom be justified. We aim to characterize the classification of strength of recommendations and confidence in estimates in World Health Organization (WHO) guidelines that used the GRADE approach and graded both strength and confidence (GRADEd). We reviewed all WHO guidelines (January 2007 to December 2012), identified those that were GRADEd, and, in these, examined the classifications of strong and weak and associated confidence in estimates (high, moderate, low, and very low). We identified 116 WHO guidelines in which 43 (37%) were GRADEd and had 456 recommendations, of which 289 (63.4%) were strong and 167 (36.6%) were conditional/weak. Of the 289 strong recommendations, 95 (33.0%) were based on evidence warranting low confidence in estimates and 65 (22.5%) on evidence warranting very low confidence in estimates (55.5% strong recommendations overall based on low or very low confidence in estimates). Strong recommendations based on low or very low confidence estimates are very frequently made in WHO guidelines. Further study to determine the reasons for such high uncertainty recommendations is warranted. Copyright © 2014 Elsevier Inc. All rights reserved.

Theory of nonlinear elasticity, stress-induced relaxation, and dynamic yielding in dense fluids of hard nonspherical colloids

NASA Astrophysics Data System (ADS)

Zhang, Rui; Schweizer, Kenneth S.

2012-04-01

We generalize the microscopic naïve mode coupling and nonlinear Langevin equation theories of the coupled translation-rotation dynamics of dense suspensions of uniaxial colloids to treat the effect of applied stress on shear elasticity, cooperative cage escape, structural relaxation, and dynamic and static yielding. The key concept is a stress-dependent dynamic free energy surface that quantifies the center-of-mass force and torque on a moving colloid. The consequences of variable particle aspect ratio and volume fraction, and the role of plastic versus double glasses, are established in the context of dense, glass-forming suspensions of hard-core dicolloids. For low aspect ratios, the theory provides a microscopic basis for the recently observed phenomenon of double yielding as a consequence of stress-driven sequential unlocking of caging constraints via reduction of the distinct entropic barriers associated with the rotational and translational degrees of freedom. The existence, and breadth in volume fraction, of the double yielding phenomena is predicted to generally depend on both the degree of particle anisotropy and experimental probing frequency, and as a consequence typically occurs only over a window of (high) volume fractions where there is strong decoupling of rotational and translational activated relaxation. At high enough concentrations, a return to single yielding is predicted. For large aspect ratio dicolloids, rotation and translation are always strongly coupled in the activated barrier hopping event, and hence for all stresses only a single yielding process is predicted.

Yield Asymmetry Design of Magnesium Alloys by Integrated Computational Materials Engineering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Dongsheng; Joshi, Vineet V.; Lavender, Curt A.

2013-11-01

Deformation asymmetry of magnesium alloys is an important factor on machine design in automobile industry. Represented by the ratio of compressive yield stress (CYS) against tensile yield stress (TYS), deformation asymmetry is strongly related to microstructure, characterized by texture and grain size. Modified intermediate phi-model, a polycrystalline viscoplasticity model, is used to predict the deformation behavior of magnesium alloys with different grain sizes. Validated with experimental results, integrated computational materials engineering is applied to find out the route in achieving desired asymmetry by thermomechanical processing. In some texture, for example, rolled texture, CYS/TYS is smaller than 1 under different loadingmore » directions. In some texture, for example, extruded texture, asymmetry is large along normal direction. Starting from rolled texture, the asymmetry will increased to close to 1 along rolling direction after compressed to a strain of 0.2. Our model shows that grain refinement increases CYS/TYS. Besides texture control, grain refinement can also optimize the yield asymmetry. After the grain size decreased to a critical value, CYS/TYS reaches to 1 since CYS increases much faster than TYS. By tailoring the microstructure using texture control and grain refinement, it is achievable to optimize yield asymmetry in wrought magnesium alloys.« less

Yield asymmetry design of magnesium alloys by integrated computational materials engineering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Dongsheng; Joshi, Vineet; Lavender, Curt

2013-11-01

Deformation asymmetry of magnesium alloys is an important factor on machine design in the automobile industry. Represented by the ratio of compressive yield stress (CYS) against tensile yield stress (TYS), deformation asymmetry is strongly related to texture and grain size. A polycrystalline viscoplasticity model, modified intermediate Φ-model, is used to predict the deformation behavior of magnesium alloys with different grain sizes. Validated with experimental results, integrated computational materials engineering is applied to find out the route in achieving desired asymmetry via thermomechanical processing. For example, CYS/TYS in rolled texture is smaller than 1 under different loading directions. In other textures,more » such as extruded texture, CYS/TYS is large along the normal direction. Starting from rolled texture, asymmetry will increase to close to 1 along the rolling direction after being compressed to a strain of 0.2. Our modified Φ-model also shows that grain refinement increases CYS/TYS. Along with texture control, grain refinement also can optimize the yield asymmetry. After the grain size decreases to a critical value, CYS/TYS reaches to 1 because CYS increases much faster than TYS. By tailoring the microstructure using texture control and grain refinement, it is achievable to optimize yield asymmetry in wrought magnesium alloys.« less

Yield Advances in Peanut

USDA-ARS?s Scientific Manuscript database

Average yields of peanut in the U.S. set an all time record of 4,695 kg ha-1 in 2012. This far exceeded the previous record yield of 3,837 kg ha-1 in 2008. Favorable weather conditions undoubtedly contributed to the record yields in 2012; however, these record yields would not have been achievable...

Potential for Improved Crop Yield Prediction Through Assimilation of Satellite-Derived Soil Moisture Data

USDA-ARS?s Scientific Manuscript database

Crop yield estimates have a strong impact on dealing with food shortages and on market demand and supply; these estimates are critical for decision-making processes by the U.S. Government, policy makers, stakeholders, etc. Most of the decision making is based on forecasts provided by the U.S. Depart...

Linking crop yield anomalies to large-scale atmospheric circulation in Europe.

PubMed

Ceglar, Andrej; Turco, Marco; Toreti, Andrea; Doblas-Reyes, Francisco J

2017-06-15

Understanding the effects of climate variability and extremes on crop growth and development represents a necessary step to assess the resilience of agricultural systems to changing climate conditions. This study investigates the links between the large-scale atmospheric circulation and crop yields in Europe, providing the basis to develop seasonal crop yield forecasting and thus enabling a more effective and dynamic adaptation to climate variability and change. Four dominant modes of large-scale atmospheric variability have been used: North Atlantic Oscillation, Eastern Atlantic, Scandinavian and Eastern Atlantic-Western Russia patterns. Large-scale atmospheric circulation explains on average 43% of inter-annual winter wheat yield variability, ranging between 20% and 70% across countries. As for grain maize, the average explained variability is 38%, ranging between 20% and 58%. Spatially, the skill of the developed statistical models strongly depends on the large-scale atmospheric variability impact on weather at the regional level, especially during the most sensitive growth stages of flowering and grain filling. Our results also suggest that preceding atmospheric conditions might provide an important source of predictability especially for maize yields in south-eastern Europe. Since the seasonal predictability of large-scale atmospheric patterns is generally higher than the one of surface weather variables (e.g. precipitation) in Europe, seasonal crop yield prediction could benefit from the integration of derived statistical models exploiting the dynamical seasonal forecast of large-scale atmospheric circulation.

Strong monogamy conjecture for multiqubit entanglement: the four-qubit case.

PubMed

Regula, Bartosz; Di Martino, Sara; Lee, Soojoon; Adesso, Gerardo

2014-09-12

We investigate the distribution of bipartite and multipartite entanglement in multiqubit states. In particular, we define a set of monogamy inequalities sharpening the conventional Coffman-Kundu-Wootters constraints, and we provide analytical proofs of their validity for relevant classes of states. We present extensive numerical evidence validating the conjectured strong monogamy inequalities for arbitrary pure states of four qubits.

Influence of management and environment on Australian wheat: information for sustainable intensification and closing yield gaps

NASA Astrophysics Data System (ADS)

Bryan, B. A.; King, D.; Zhao, G.

2014-04-01

In the future, agriculture will need to produce more, from less land, more sustainably. But currently, in many places, actual crop yields are below those attainable. We quantified the ability for agricultural management to increase wheat yields across 179 Mha of potentially arable land in Australia. Using the Agricultural Production Systems Simulator (APSIM), we simulated the impact on wheat yield of 225 fertilization and residue management scenarios at a high spatial, temporal, and agronomic resolution from 1900 to 2010. The influence of management and environmental variables on wheat yield was then assessed using Spearman’s non-parametric correlation test with bootstrapping. While residue management showed little correlation, fertilization strongly increased wheat yield up to around 100 kg N ha-1 yr-1. However, this effect was highly dependent on the key environment variables of rainfall, temperature, and soil water holding capacity. The influence of fertilization on yield was stronger in cooler, wetter climates, and in soils with greater water holding capacity. We conclude that the effectiveness of management intensification to increase wheat yield is highly dependent upon local climate and soil conditions. We provide context-specific information on the yield benefits of fertilization to support adaptive agronomic decision-making and contribute to the closure of yield gaps. We also suggest that future assessments consider the economic and environmental sustainability of management intensification for closing yield gaps.

Acetylcholinesterase inhibitors and memantine in bipolar disorder: A systematic review and best evidence synthesis of the efficacy and safety for multiple disease dimensions.

PubMed

Veronese, Nicola; Solmi, Marco; Luchini, Claudio; Lu, Ru-Band; Stubbs, Brendon; Zaninotto, Leonardo; Correll, Christoph U

2016-06-01

Acetylcholinesterase inhibitors (AceI) and memantine might prove useful in bipolar disorder (BD) given their neuroprotective and pro-cognitive effects, as highlighted by several case reports. We aimed to systematically review the efficacy and safety of AceI and memantine across multiple outcome dimensions in BD. Systematic PubMed and SCOPUS search until 04/17/2015 without language restrictions. Included were randomized controlled trials (RCTs), open label studies and case series of AceI or memantine in BD patients reporting quantitative data on depression, mania, psychotic symptoms, global functioning, or cognitive performance. We summarized results using a best-evidence based synthesis. Out of 214 hits, 12 studies (RCTs=5, other designs=7, total n=422) were included. Donepezil (studies=5; treated=102 vs. placebo=21): there was strong evidence for no effect on mania and psychotic symptoms; low evidence indicating no effect on depression. Galantamine (studies=3; treated=21 vs. controls=20) (placebo=10, healthy subjects=10): there was strong evidence for no effect on mania; moderate evidence for no effect on depression; low evidence for no effect on global functioning. Memantine (studies=4; treated=152 vs. placebo=88): there was conflicting evidence regarding efficacy for mania, depression and global functioning. Paucity of RCTs; small sample size studies; heterogeneous design, outcome and patient characteristics. There is limited but converging evidence of no effect of AceI in BD, and conflicting evidence about memantine in BD. Too few studies of mostly medium/low quality and lacking sufficient numbers of patients in specific mood states, especially mania, contributed data, focusing solely on short-term/medium-term treatment, necessitating additional high-quality research to yield more definite results. Copyright © 2016 Elsevier B.V. All rights reserved.

Effectiveness of Workplace Interventions in Return-to-Work for Musculoskeletal, Pain-Related and Mental Health Conditions: An Update of the Evidence and Messages for Practitioners.

PubMed

Cullen, K L; Irvin, E; Collie, A; Clay, F; Gensby, U; Jennings, P A; Hogg-Johnson, S; Kristman, V; Laberge, M; McKenzie, D; Newnam, S; Palagyi, A; Ruseckaite, R; Sheppard, D M; Shourie, S; Steenstra, I; Van Eerd, D; Amick, B C

2018-03-01

Purpose The objective of this systematic review was to synthesize evidence on the effectiveness of workplace-based return-to-work (RTW) interventions and work disability management (DM) interventions that assist workers with musculoskeletal (MSK) and pain-related conditions and mental health (MH) conditions with RTW. Methods We followed a systematic review process developed by the Institute for Work & Health and an adapted best evidence synthesis that ranked evidence as strong, moderate, limited, or insufficient. Results Seven electronic databases were searched from January 1990 until April 2015, yielding 8898 non-duplicate references. Evidence from 36 medium and high quality studies were synthesized on 12 different intervention categories across three broad domains: health-focused, service coordination, and work modification interventions. There was strong evidence that duration away from work from both MSK or pain-related conditions and MH conditions were significantly reduced by multi-domain interventions encompassing at least two of the three domains. There was moderate evidence that these multi-domain interventions had a positive impact on cost outcomes. There was strong evidence that cognitive behavioural therapy interventions that do not also include workplace modifications or service coordination components are not effective in helping workers with MH conditions in RTW. Evidence for the effectiveness of other single-domain interventions was mixed, with some studies reporting positive effects and others reporting no effects on lost time and work functioning. Conclusions While there is substantial research literature focused on RTW, there are only a small number of quality workplace-based RTW intervention studies that involve workers with MSK or pain-related conditions and MH conditions. We recommend implementing multi-domain interventions (i.e. with healthcare provision, service coordination, and work accommodation components) to help reduce lost time for

High-resolution, regional-scale crop yield simulations for the Southwestern United States

NASA Astrophysics Data System (ADS)

Stack, D. H.; Kafatos, M.; Medvigy, D.; El-Askary, H. M.; Hatzopoulos, N.; Kim, J.; Kim, S.; Prasad, A. K.; Tremback, C.; Walko, R. L.; Asrar, G. R.

2012-12-01

Over the past few decades, there have been many process-based crop models developed with the goal of better understanding the impacts of climate, soils, and management decisions on crop yields. These models simulate the growth and development of crops in response to environmental drivers. Traditionally, process-based crop models have been run at the individual farm level for yield optimization and management scenario testing. Few previous studies have used these models over broader geographic regions, largely due to the lack of gridded high-resolution meteorological and soil datasets required as inputs for these data intensive process-based models. In particular, assessment of regional-scale yield variability due to climate change requires high-resolution, regional-scale, climate projections, and such projections have been unavailable until recently. The goal of this study was to create a framework for extending the Agricultural Production Systems sIMulator (APSIM) crop model for use at regional scales and analyze spatial and temporal yield changes in the Southwestern United States (CA, AZ, and NV). Using the scripting language Python, an automated pipeline was developed to link Regional Climate Model (RCM) output with the APSIM crop model, thus creating a one-way nested modeling framework. This framework was used to combine climate, soil, land use, and agricultural management datasets in order to better understand the relationship between climate variability and crop yield at the regional-scale. Three different RCMs were used to drive APSIM: OLAM, RAMS, and WRF. Preliminary results suggest that, depending on the model inputs, there is some variability between simulated RCM driven maize yields and historical yields obtained from the United States Department of Agriculture (USDA). Furthermore, these simulations showed strong non-linear correlations between yield and meteorological drivers, with critical threshold values for some of the inputs (e.g. minimum and

Are interventions to enhance communication performance in allied health professionals effective, and how should they be delivered? Direct and indirect evidence.

PubMed

Parry, Ruth

2008-11-01

(1) To systematically review direct evidence about effects of interventions to improve communication performance amongst allied health professionals (AHPs). (2) To summarise indirect evidence pertinent to design, delivery, effects, and evaluation of such interventions. (1) Systematic search and narrative review of evaluations of interventions for AHPs. (2) Systematic search and narrative summary of reviews of corresponding interventions in medicine and nursing. Five reports of interventions for AHPs were included. All reported positive effects of training. Strongest evidence was from two small-n within-subjects controlled studies that evaluated highly specific training for qualified therapists in brain injury rehabilitation environments. Indirect evidence from nine systematic reviews in medicine and nursing indicated positive effects of communication training. Robust designs yielded smallest effect sizes. Interventions based on strong conceptual and empirical foundations and targeting specific areas of practice appeared more effective. Strongest evidence is for performance-based training for clinicians already working with patients. More empirical and conceptual understandings about AHPs' communication practices are required so as to improve the design, delivery and subsequent evaluation of communication training amongst these important healthcare workers. Preliminary and indirect evidence suggest it is possible to positively influence AHP clinicians' performance and patients' outcomes if training interventions are specific, founded on evidence about effective practice and delivered using practical modalities.

Growth, Yield and Fruit Quality of Grapevines under Organic and Biodynamic Management

PubMed Central

Döring, Johanna; Frisch, Matthias; Tittmann, Susanne; Stoll, Manfred; Kauer, Randolf

2015-01-01

The main objective of this study was to determine growth, yield and fruit quality of grapevines under organic and biodynamic management in relation to integrated viticultural practices. Furthermore, the mechanisms for the observed changes in growth, yield and fruit quality were investigated by determining nutrient status, physiological performance of the plants and disease incidence on bunches in three consecutive growing seasons. A field trial (Vitis vinifera L. cv. Riesling) was set up at Hochschule Geisenheim University, Germany. The integrated treatment was managed according to the code of good practice. Organic and biodynamic plots were managed according to Regulation (EC) No 834/2007 and Regulation (EC) No 889/2008 and according to ECOVIN- and Demeter-Standards, respectively. The growth and yield of the grapevines differed strongly among the different management systems, whereas fruit quality was not affected by the management system. The organic and the biodynamic treatments showed significantly lower growth and yield in comparison to the integrated treatment. The physiological performance was significantly lower in the organic and the biodynamic systems, which may account for differences in growth and cluster weight and might therefore induce lower yields of the respective treatments. Soil management and fertilization strategy could be responsible factors for these changes. Yields of the organic and the biodynamic treatments partially decreased due to higher disease incidence of downy mildew. The organic and the biodynamic plant protection strategies that exclude the use of synthetic fungicides are likely to induce higher disease incidence and might partially account for differences in the nutrient status of vines under organic and biodynamic management. Use of the biodynamic preparations had little influence on vine growth and yield. Due to the investigation of important parameters that induce changes especially in growth and yield of grapevines under

Breeding progress, environmental variation and correlation of winter wheat yield and quality traits in German official variety trials and on-farm during 1983-2014.

PubMed

Laidig, Friedrich; Piepho, Hans-Peter; Rentel, Dirk; Drobek, Thomas; Meyer, Uwe; Huesken, Alexandra

2017-01-01

Over the last 32 years, a large gain in grain yield (24 %) was achieved in official German variety trials, and despite considerable loss in protein concentration (-7.9 %), winter wheat baking quality was partially improved over the last 32 years. On-farm gain in grain yield (32 %) exceeded gain in trials, but at yield level about 25 dt ha -1 lower. Breeding progress was very successfully transferred into both progress in grain yield and on-farm baking quality. Long-term gains in grain yield and baking quality of 316 winter wheat varieties from German official trials were evaluated. We dissected progress into a genetic and a non-genetic part to quantify the contribution of genetic improvement. We further investigated the influence of genotype and environment on total variation by estimating variance components. We also estimated genetic and phenotypic correlation between quality traits. For trial data, we found a large gain in grain yield (24%), but a strong decline in protein concentration (-8.0%) and loaf volume (-8.5%) relative to 1983. Improvement of baking quality could be achieved for falling number (5.8%), sedimentation value (7.9%), hardness (13.4%), water absorption (1.2%) and milling yield (2.4%). Grain yield, falling number and protein concentration were highly influenced by environment, whereas for sedimentation value, hardness, water absorption and loaf volume genotypes accounted for more than 60% of total variation. Strong to very strong relations exist among protein concentration, sedimentation value, and loaf volume. On-farm yields were obtained from national statistics, and grain quality data from samples collected by national harvest survey. These on-farm data were compared with trial results. On-farm gain in grain yield was 31.6%, but at a mean level about 25 dt ha -1  lower. Improvement of on-farm quality exceeded trial results considerably. A shift to varieties with improved baking quality can be considered as the main reason for this

Effects of body conformation and udder morphology on milk yield of zebu cows in North region of Cameroon

PubMed Central

Mingoas, Kilekoung Jean-Pierre; Awah-Ndukum, Julius; Dakyang, Houinga; Zoli, Pagnah André

2017-01-01

Aim: The aim of the study was to assess the effect of udder morphological characteristics on milk yield in zebu cows of Cameroon. Materials and Methods: The diameter and height of the udder, length and diameter of the teat, and the milk yield were measured in 29 Djafun (Red Mbororo) and 19 Aku (White Fulani) cows in Louggueré zootechnical station in the North region of Cameroon. Results: Overall, strong positive correlation (rp=0.60) between the diameter (240.21±28.58 mm) and height (131.12±23.64 mm) of udders (p<0.001) and between length (39.51±6.44 mm) and diameter (19.85±3.08 mm) of teats (rp=0.78) were found in the zebu cows. Udder morphologic characteristics varied significantly (p<0.005) according to breed, lactation stage and parity, and height at whiters. There was significant (p<0.001) correlations between udder diameter (rp=0.541) and height (rp=0.549) with milk yield. Conclusion: This study ascertained udder morphological characteristics values in local zebu cows, and showed that udder size is strong and positively correlated to milk yield. The findings are useful in genetic improvement programs of zebu cows. PMID:28919680

Soviet test yields

NASA Astrophysics Data System (ADS)

Vergino, Eileen S.

Soviet seismologists have published descriptions of 96 nuclear explosions conducted from 1961 through 1972 at the Semipalatinsk test site, in Kazakhstan, central Asia [Bocharov et al., 1989]. With the exception of releasing news about some of their peaceful nuclear explosions (PNEs) the Soviets have never before published such a body of information.To estimate the seismic yield of a nuclear explosion it is necessary to obtain a calibrated magnitude-yield relationship based on events with known yields and with a consistent set of seismic magnitudes. U.S. estimation of Soviet test yields has been done through application of relationships to the Soviet sites based on the U.S. experience at the Nevada Test Site (NTS), making some correction for differences due to attenuation and near-source coupling of seismic waves.

A Deep Chandra ACIS Study of NGC 4151. II. The Innermost Emission Line Region and Strong Evidence for Radio Jet-NLR Cloud Collision

NASA Astrophysics Data System (ADS)

Wang, Junfeng; Fabbiano, Giuseppina; Elvis, Martin; Risaliti, Guido; Mundell, Carole G.; Karovska, Margarita; Zezas, Andreas

2011-07-01

We have studied the X-ray emission within the inner ~150 pc radius of NGC 4151 by constructing high spatial resolution emission line images of blended O VII, O VIII, and Ne IX. These maps show extended structures that are spatially correlated with the radio outflow and optical [O III] emission. We find strong evidence for jet-gas cloud interaction, including morphological correspondences with regions of X-ray enhancement, peaks of near-infrared [Fe II] emission, and optical clouds. In these regions, moreover, we find evidence of elevated Ne IX/O VII ratios; the X-ray emission of these regions also exceeds that expected from nuclear photoionization. Spectral fitting reveals the presence of a collisionally ionized component. The thermal energy of the hot gas suggests that >~ 0.1% of the estimated jet power is deposited into the host interstellar medium through interaction between the radio jet and the dense medium of the circumnuclear region. We find possible pressure equilibrium between the collisionally ionized hot gas and the photoionized line-emitting cool clouds. We also obtain constraints on the extended iron and silicon fluorescent emission. Both lines are spatially unresolved. The upper limit on the contribution of an extended emission region to the Fe Kα emission is <~ 5% of the total, in disagreement with a previous claim that 65% of the Fe Kα emission originates in the extended narrow line region.

Describing a Strongly Correlated Model System with Density Functional Theory.

PubMed

Kong, Jing; Proynov, Emil; Yu, Jianguo; Pachter, Ruth

2017-07-06

The linear chain of hydrogen atoms, a basic prototype for the transition from a metal to Mott insulator, is studied with a recent density functional theory model functional for nondynamic and strong correlation. The computed cohesive energy curve for the transition agrees well with accurate literature results. The variation of the electronic structure in this transition is characterized with a density functional descriptor that yields the atomic population of effectively localized electrons. These new methods are also applied to the study of the Peierls dimerization of the stretched even-spaced Mott insulator to a chain of H 2 molecules, a different insulator. The transitions among the two insulating states and the metallic state of the hydrogen chain system are depicted in a semiquantitative phase diagram. Overall, we demonstrate the capability of studying strongly correlated materials with a mean-field model at the fundamental level, in contrast to the general pessimistic view on such a feasibility.

Impact of heterozygosity and heterogeneity on cotton lint yield stability: II. Lint yield components

USDA-ARS?s Scientific Manuscript database

In order to determine which yield components may contribute to yield stability, an 18-environment field study was undertaken to observe the mean, standard deviation (SD), and coefficient of variation (CV) for cotton lint yield components in population types that differed for lint yield stability. Th...

Kinetics of Strong Acid Hydrolysis of a Bleached Kraft Pulp for Producing Cellulose Nanocrystals (CNCs)

Treesearch

Qianqian Wang; Xuebing Zhao; J.Y. Zhu

2014-01-01

Cellulose nanocrytals (CNCs) are predominantly produced using the traditional strong acid hydrolysis process. In most reported studies, the typical CNC yield is low (approximately 30%) despite process optimization. This study investigated the hydrolysis of a bleached kraft eucalyptus pulp using sulfuric acid between 50 and 64 wt % at temperatures of 35−80 °C...

Strong cellulase inhibition by Mannan polysaccharides in cellulose conversion to sugars.

PubMed

Kumar, Rajeev; Wyman, Charles E

2014-07-01

Cellulase enzymes contribute a major fraction of the total cost for biological conversion of lignocellulosic biomass to fuels and chemicals. Although a several fold reduction in cellulase production costs and enhancement of cellulase activity and stability have been reported in recent years, sugar yields are still lower at low enzyme doses than desired commercially. We recently reported that hemicellulose xylan and its oligomers strongly inhibit cellulase and that supplementation of cellulase with xylanase and β-xylosidase would significantly reduce such inhibition. In this study, mannan polysaccharides and their enzymatically prepared hydrolyzates were discovered to be strongly inhibitory to fungal cellulase in cellulose conversion (>50% drop in % relative conversion), even at a small concentration of 0.1 g/L, and inhibition was much greater than experienced by other known inhibitors such as cellobiose, xylooligomers, and furfural. Furthermore, cellulase inhibition dramatically increased with heteromannan loading and mannan substitution with galactose side units. In general, enzymatically prepared hydrolyzates were less inhibitory than their respective mannan polysaccharides except highly substituted ones. Supplementation of cellulase with commercial accessory enzymes such as xylanase, pectinase, and β-glucosidase was effective in greatly relieving inhibition but only for less substituted heteromannans. However, cellulase supplementation with purified heteromannan specific enzymes relieved inhibition by these more substituted heteromannans as well, suggesting that commercial preparations need to have higher amounts of such activities to realize high sugar yields at the low enzyme protein loadings needed for low cost fuels production. © 2014 Wiley Periodicals, Inc.

Engineering applications of strong ground motion simulation

NASA Astrophysics Data System (ADS)

Somerville, Paul

1993-02-01

design response spectra for crustal earthquakes at a power plant site in California and for subduction earthquakes in the Seattle-Portland region. We also demonstrate the use of simulation methods for modeling the attenuation of strong ground motion, and show evidence of the effect of critical reflections from the lower crust in causing the observed flattening of the attenuation of strong ground motion from the 1988 Saguenay, Quebec, and 1989 Loma Prieta earthquakes.

Strong Pitch-Angle Diffusion of Ring Current Ions in Geomagnetic Storm-Associated Conditions

NASA Technical Reports Server (NTRS)

Khazanov, G. V.; Gamayunov, K. V.; Gallagher, D. L.; Spann, J. F.

2005-01-01

Do electromagnetic ion cyclotron (EMIC) waves cause strong pitch-angle diffusion of RC ions? This question is the primary motivation of this paper and has been affirmatively answered from the theoretical point of view. The materials that are presented in the Results section show clear evidence that strong pitch-angle diffusion takes place in the inner magnetosphere indicating an important role for the wave-particle interaction mechanism in the formation of RC ions and EMIC waves.

Fishing diseased abalone to promote yield and conservation

PubMed Central

Ben-Horin, Tal; Bidegain, Gorka; Lenihan, Hunter S.

2016-01-01

Past theoretical models suggest fishing disease-impacted stocks can reduce parasite transmission, but this is a good management strategy only when the exploitation required to reduce transmission does not overfish the stock. We applied this concept to a red abalone fishery so impacted by an infectious disease (withering syndrome) that stock densities plummeted and managers closed the fishery. In addition to the non-selective fishing strategy considered by past disease-fishing models, we modelled targeting (culling) infected individuals, which is plausible in red abalone because modern diagnostic tools can determine infection without harming landed abalone and the diagnostic cost is minor relative to the catch value. The non-selective abalone fishing required to eradicate parasites exceeded thresholds for abalone sustainability, but targeting infected abalone allowed the fishery to generate yield and reduce parasite prevalence while maintaining stock densities at or above the densities attainable if the population was closed to fishing. The effect was strong enough that stock and yield increased even when the catch was one-third uninfected abalone. These results could apply to other fisheries as the diagnostic costs decline relative to catch value. PMID:26880843

Fishing diseased abalone to promote yield and conservation.

PubMed

Ben-Horin, Tal; Lafferty, Kevin D; Bidegain, Gorka; Lenihan, Hunter S

2016-03-05

Past theoretical models suggest fishing disease-impacted stocks can reduce parasite transmission, but this is a good management strategy only when the exploitation required to reduce transmission does not overfish the stock. We applied this concept to a red abalone fishery so impacted by an infectious disease (withering syndrome) that stock densities plummeted and managers closed the fishery. In addition to the non-selective fishing strategy considered by past disease-fishing models, we modelled targeting (culling) infected individuals, which is plausible in red abalone because modern diagnostic tools can determine infection without harming landed abalone and the diagnostic cost is minor relative to the catch value. The non-selective abalone fishing required to eradicate parasites exceeded thresholds for abalone sustainability, but targeting infected abalone allowed the fishery to generate yield and reduce parasite prevalence while maintaining stock densities at or above the densities attainable if the population was closed to fishing. The effect was strong enough that stock and yield increased even when the catch was one-third uninfected abalone. These results could apply to other fisheries as the diagnostic costs decline relative to catch value. © 2016 The Author(s).

Fishing diseased abalone to promote yield and conservation

USGS Publications Warehouse

Ben-Horin, Tal; Lafferty, Kevin D.; Bidegain, Gorka; Lenihan, Hunter S.

2016-01-01

Past theoretical models suggest fishing disease-impacted stocks can reduce parasite transmission, but this is a good management strategy only when the exploitation required to reduce transmission does not overfish the stock. We applied this concept to a red abalone fishery so impacted by an infectious disease (withering syndrome) that stock densities plummeted and managers closed the fishery. In addition to the non-selective fishing strategy considered by past disease-fishing models, we modelled targeting (culling) infected individuals, which is plausible in red abalone because modern diagnostic tools can determine infection without harming landed abalone and the diagnostic cost is minor relative to the catch value. The non-selective abalone fishing required to eradicate parasites exceeded thresholds for abalone sustainability, but targeting infected abalone allowed the fishery to generate yield and reduce parasite prevalence while maintaining stock densities at or above the densities attainable if the population was closed to fishing. The effect was strong enough that stock and yield increased even when the catch was one-third uninfected abalone. These results could apply to other fisheries as the diagnostic costs decline relative to catch value.

Formation of Globular Clusters with Internal Abundance Spreads in r-Process Elements: Strong Evidence for Prolonged Star Formation

NASA Astrophysics Data System (ADS)

Bekki, Kenji; Tsujimoto, Takuji

2017-07-01

Several globular clusters (GCs) in the Galaxy are observed to show internal abundance spreads in r-process elements (e.g., Eu). We propose a new scenario that explains the origin of these GCs (e.g., M5 and M15). In this scenario, stars with no/little abundance variations first form from a massive molecular cloud (MC). After all of the remaining gas of the MC is expelled by numerous supernovae, gas ejected from asymptotic giant branch stars can be accumulated in the central region of the GC to form a high-density intracluster medium (ICM). Merging of neutron stars then occurs to eject r-process elements, which can be efficiently trapped in and subsequently mixed with the ICM. New stars formed from the ICM can have r-process abundances that are quite different from those of earlier generations of stars within the GC. This scenario can explain both (I) why r-process elements can be trapped within GCs and (II) why GCs with internal abundance spreads in r-process elements do not show [Fe/H] spreads. Our model shows (I) that a large fraction of Eu-rich stars can be seen in Na-enhanced stellar populations of GCs, as observed in M15, and (II) why most of the Galactic GCs do not exhibit such internal abundance spreads. Our model demonstrates that the observed internal spreads of r-process elements in GCs provide strong evidence for prolonged star formation (˜108 yr).

Using normalized difference vegetation index (NDVI) to estimate sugarcane yield and yield components

USDA-ARS?s Scientific Manuscript database

Sugarcane (Saccharum spp.) yield and yield components are important traits for growers and scientists to evaluate and select cultivars. Collection of these yield data would be labor intensive and time consuming in the early selection stages of sugarcane breeding cultivar development programs with a ...

Nanoscale Roughness of Natural Fault Surfaces Controlled by Scale-Dependent Yield Strength

NASA Astrophysics Data System (ADS)

Thom, C. A.; Brodsky, E. E.; Carpick, R. W.; Pharr, G. M.; Oliver, W. C.; Goldsby, D. L.

2017-09-01

Many natural fault surfaces exhibit remarkably similar scale-dependent roughness, which may reflect the scale-dependent yield strength of rocks. Using atomic force microscopy (AFM), we show that a sample of the Corona Heights Fault exhibits isotropic surface roughness well-described by a power law, with a Hurst exponent of 0.75 +/- 0.05 at all wavelengths from 60 nm to 10 μm. The roughness data and a recently proposed theoretical framework predict that yield strength varies with length scale as λ-0.25+/-0.05. Nanoindentation tests on the Corona Heights sample and another fault sample whose topography was previously measured with AFM (the Yair Fault) reveal a scale-dependent yield stress with power-law exponents of -0.12 +/- 0.06 and -0.18 +/- 0.08, respectively. These values are within one to two standard deviations of the predicted value, and provide experimental evidence that fault roughness is controlled by intrinsic material properties, which produces a characteristic surface geometry.

Phenotypic Stability of Zea mays Grain Yield and Its Attributing Traits under Drought Stress

PubMed Central

Ali, Fawad; Ahsan, Muhammad; Ali, Qurban; Kanwal, Naila

2017-01-01

Phenotypic stability under stress environment facilitate the fitness of genotype and opens new horizons to explore the cryptic genetic variation. Variation in tolerance to drought stress, a major grain yield constraint to global maize production, was identified, at the phenotypic and genotypic level. Here we found a prominent hybrid H9 that showed fitness over four growing seasons for grain yield under water stress conditions. Genotypic and phenotypic correlation of yield attributing traits over four seasons demonstrated that cobs per plant, 100 seed weight, number of grains rows per cob, total dry matter, cob diameter had positive association (r2 = 0.3–0.9) to grain yield. The perturbation was found for chlorophyll content as it showed moderate to strong association (P < 0.01) over four seasons, might be due to environment or genotype dependent. Highest heritability (95%) and genetic advance (79%) for grain yield was found in H9 over four consecutive crop growing seasons. Combined analysis over four seasons showed that studied variables together explained 85% of total variation in dependent structure (grain yield) obtained by Principal component analysis. This significant finding is the best example of phenotypic stability of grain yield in H9 and made it best fitted for grain yield under drought stress scenario. Detailed genetic analysis of H9 will help us to identify significant loci and alleles that made H9 the best fitted and it could serve as a potential source to generate novel transgressive levels of tolerance for drought stress in arid/semiarid regions. PMID:28878785

Phenotypic Stability of Zea mays Grain Yield and Its Attributing Traits under Drought Stress.

PubMed

Ali, Fawad; Ahsan, Muhammad; Ali, Qurban; Kanwal, Naila

2017-01-01

Phenotypic stability under stress environment facilitate the fitness of genotype and opens new horizons to explore the cryptic genetic variation. Variation in tolerance to drought stress, a major grain yield constraint to global maize production, was identified, at the phenotypic and genotypic level. Here we found a prominent hybrid H 9 that showed fitness over four growing seasons for grain yield under water stress conditions. Genotypic and phenotypic correlation of yield attributing traits over four seasons demonstrated that cobs per plant, 100 seed weight, number of grains rows per cob, total dry matter, cob diameter had positive association ( r 2 = 0.3-0.9) to grain yield. The perturbation was found for chlorophyll content as it showed moderate to strong association ( P < 0.01) over four seasons, might be due to environment or genotype dependent. Highest heritability (95%) and genetic advance (79%) for grain yield was found in H 9 over four consecutive crop growing seasons. Combined analysis over four seasons showed that studied variables together explained 85% of total variation in dependent structure (grain yield) obtained by Principal component analysis. This significant finding is the best example of phenotypic stability of grain yield in H 9 and made it best fitted for grain yield under drought stress scenario. Detailed genetic analysis of H 9 will help us to identify significant loci and alleles that made H 9 the best fitted and it could serve as a potential source to generate novel transgressive levels of tolerance for drought stress in arid/semiarid regions.

Compression of freestanding gold nanostructures: from stochastic yield to predictable flow

NASA Astrophysics Data System (ADS)

Mook, W. M.; Niederberger, C.; Bechelany, M.; Philippe, L.; Michler, J.

2010-02-01

Characterizing the mechanical response of isolated nanostructures is vitally important to fields such as microelectromechanical systems (MEMS) where the behaviour of nanoscale contacts can in large part determine system reliability and lifetime. To address this challenge directly, single crystal gold nanodots are compressed inside a high resolution scanning electron microscope (SEM) using a nanoindenter equipped with a flat punch tip. These structures load elastically, and then yield in a stochastic manner, at loads ranging from 16 to 110 µN, which is up to five times higher than the load necessary for flow after yield. Yielding is immediately followed by displacement bursts equivalent to 1-50% of the initial height, depending on the yield point. During the largest displacement bursts, strain energy within the structure is released while new surface area is created in the form of localized slip bands, which are evident in both the SEM movies and still-images. A first order estimate of the apparent energy release rate, in terms of fracture mechanics concepts, for bursts representing 5-50% of the structure's initial height is on the order of 10-100 J m-2, which is approximately two orders of magnitude lower than bulk values. Once this initial strain burst during yielding has occurred, the structures flow in a ductile way. The implications of this behaviour, which is analogous to a brittle to ductile transition, are discussed with respect to mechanical reliability at the micro- and nanoscales.

Terapascal static pressure generation with ultrahigh yield strength nanodiamond.

PubMed

Dubrovinskaia, Natalia; Dubrovinsky, Leonid; Solopova, Natalia A; Abakumov, Artem; Turner, Stuart; Hanfland, Michael; Bykova, Elena; Bykov, Maxim; Prescher, Clemens; Prakapenka, Vitali B; Petitgirard, Sylvain; Chuvashova, Irina; Gasharova, Biliana; Mathis, Yves-Laurent; Ershov, Petr; Snigireva, Irina; Snigirev, Anatoly

2016-07-01

Studies of materials' properties at high and ultrahigh pressures lead to discoveries of unique physical and chemical phenomena and a deeper understanding of matter. In high-pressure research, an achievable static pressure limit is imposed by the strength of available strong materials and design of high-pressure devices. Using a high-pressure and high-temperature technique, we synthesized optically transparent microballs of bulk nanocrystalline diamond, which were found to have an exceptional yield strength (~460 GPa at a confining pressure of ~70 GPa) due to the unique microstructure of bulk nanocrystalline diamond. We used the nanodiamond balls in a double-stage diamond anvil cell high-pressure device that allowed us to generate static pressures beyond 1 TPa, as demonstrated by synchrotron x-ray diffraction. Outstanding mechanical properties (strain-dependent elasticity, very high hardness, and unprecedented yield strength) make the nanodiamond balls a unique device for ultrahigh static pressure generation. Structurally isotropic, homogeneous, and made of a low-Z material, they are promising in the field of x-ray optical applications.

Terapascal static pressure generation with ultrahigh yield strength nanodiamond

PubMed Central

Dubrovinskaia, Natalia; Dubrovinsky, Leonid; Solopova, Natalia A.; Abakumov, Artem; Turner, Stuart; Hanfland, Michael; Bykova, Elena; Bykov, Maxim; Prescher, Clemens; Prakapenka, Vitali B.; Petitgirard, Sylvain; Chuvashova, Irina; Gasharova, Biliana; Mathis, Yves-Laurent; Ershov, Petr; Snigireva, Irina; Snigirev, Anatoly

2016-01-01

Studies of materials’ properties at high and ultrahigh pressures lead to discoveries of unique physical and chemical phenomena and a deeper understanding of matter. In high-pressure research, an achievable static pressure limit is imposed by the strength of available strong materials and design of high-pressure devices. Using a high-pressure and high-temperature technique, we synthesized optically transparent microballs of bulk nanocrystalline diamond, which were found to have an exceptional yield strength (~460 GPa at a confining pressure of ~70 GPa) due to the unique microstructure of bulk nanocrystalline diamond. We used the nanodiamond balls in a double-stage diamond anvil cell high-pressure device that allowed us to generate static pressures beyond 1 TPa, as demonstrated by synchrotron x-ray diffraction. Outstanding mechanical properties (strain-dependent elasticity, very high hardness, and unprecedented yield strength) make the nanodiamond balls a unique device for ultrahigh static pressure generation. Structurally isotropic, homogeneous, and made of a low-Z material, they are promising in the field of x-ray optical applications. PMID:27453944

Dark matter and dark energy from the solution of the strong CP problem.

PubMed

Mainini, Roberto; Bonometto, Silvio A

2004-09-17

The Peccei-Quinn (PQ) solution of the strong CP problem requires the existence of axions, which are viable candidates for dark matter. If the Nambu-Goldstone potential of the PQ model is replaced by a potential V(|Phi|) admitting a tracker solution, the scalar field |Phi| can account for dark energy, while the phase of Phi yields axion dark matter. If V is a supergravity (SUGRA) potential, the model essentially depends on a single parameter, the energy scale Lambda. Once we set Lambda approximately equal to 10(10) GeV at the quark-hadron transition, |Phi| naturally passes through values suitable to solve the strong CP problem, later growing to values providing fair amounts of dark matter and dark energy.

A Study of Poisson's Ratio in the Yield Region

NASA Technical Reports Server (NTRS)

Gerard, George; Wildhorn, Sorrel

1952-01-01

In the yield region of the stress-strain curve the variation in Poisson's ratio from the elastic to the plastic value is most pronounced. This variation was studied experimentally by a systematic series of tests on several aluminum alloys. The tests were conducted under simple tensile and compressive loading along three orthogonal axes. A theoretical variation of Poisson's ratio for an orthotropic solid was obtained from dilatational considerations. The assumptions used in deriving the theory were examined by use of the test data and were found to be in reasonable agreement with experimental evidence.

What has changed in the evidence for early experience? Update of a BEME systematic review.

PubMed

Yardley, Sarah; Littlewood, Sonia; Margolis, Stephen A; Scherpbier, Albert; Spencer, John; Ypinazar, Valmae; Dornan, Tim

2010-01-01

We previously reviewed evidence published from 1992 to 2001 concerning early experience for healthcare undergraduates (Dornan T, Littlewood S, Margolis S, Scherpbier A, Spencer J, Ypinazar V. 2006. How can experience in clinical and community settings contribute to early medical education? A BEME systematic review. Med Teach 28:3-18). This subsequent study reviews evidence published from 2002 to 2008. Identify changes in the evidence base; determine the value of re-reviewing; set a future research agenda. The same search strategy as in the original review was repeated. Newly identified publications were critically appraised against the same benchmarks of strength and educational importance. Twenty-four new empirical studies of early authentic experience in education of health professionals met our inclusion criteria, yielding 96 outcomes. Sixty five outcomes (from 22 studies) were both educationally important and based on strong evidence. A new significant theme was found: the use of early experience to help students understand and align themselves with patient and community perspectives on illness and healthcare. More publications were now from outside Europe and North America. In addition to supporting the findings of our original review, this update shows an expansion in research sources, and a shift in research content focus. There are still questions, however, about how early authentic experience leads to particular learning outcomes and what will make it most educationally effective.

Strong claims and weak evidence: reassessing the predictive validity of the IAT.

PubMed

Blanton, Hart; Jaccard, James; Klick, Jonathan; Mellers, Barbara; Mitchell, Gregory; Tetlock, Philip E

2009-05-01

The authors reanalyzed data from 2 influential studies-A. R. McConnell and J. M. Leibold and J. C. Ziegert and P. J. Hanges-that explore links between implicit bias and discriminatory behavior and that have been invoked to support strong claims about the predictive validity of the Implicit Association Test. In both of these studies, the inclusion of race Implicit Association Test scores in regression models reduced prediction errors by only tiny amounts, and Implicit Association Test scores did not permit prediction of individual-level behaviors. Furthermore, the results were not robust when the impact of rater reliability, statistical specifications, and/or outliers were taken into account, and reanalysis of A. R. McConnell & J. M. Leibold (2001) revealed a pattern of behavior consistent with a pro-Black behavioral bias, rather than the anti-Black bias suggested in the original study. (c) 2009 APA, all rights reserved.

Yield of active screening for tuberculosis among asylum seekers in Germany: a systematic review and meta-analysis

PubMed Central

Bozorgmehr, Kayvan; Razum, Oliver; Saure, Daniel; Joggerst, Brigitte; Szecsenyi, Joachim; Stock, Christian

2017-01-01

All asylum seekers in Germany undergo upon-entry screening for tuberculosis TB, but comprehensive evidence on the yield is lacking. We compared the national estimates with the international literature in a systematic review and meta-analysis of studies reporting the yield of TB, defined as the fraction of active TB cases detected among asylum seekers screened in Germany upon entry. We searched 11 national and international databases for empirical studies and the internet for grey literature published in English or German without restrictions on publication time. Among 1,253 screened articles, we identified six articles reporting the yield of active TB based on German data, ranging from 0.72 (95% confidence interval (CI): 0.45–1.10) to 6.41 (95% CI: 4.19–9.37) per 1,000 asylum seekers. The pooled estimate across all studies was 3.47 (95% CI: 1.78–5.73; I2 = 94.9%; p < 0.0001) per 1,000 asylum seekers. This estimate was in line with international evidence (I2 = 0%; p for heterogeneity 0.55). The meta-analysis of available international estimates resulted in a pooled yield of 3.04 (95% CI: 2.24–3.96) per 1,000. This study provides an estimate across several German federal states for the yield of TB screening in asylum seekers. Further research is needed to develop more targeted screening programmes. PMID:28367795

Measurement of CP observables in B{sup {+-}{yields}D}{sub CP}K{sup {+-}}decays and constraints on the CKM angle {gamma}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Amo Sanchez, P. del; Lees, J. P.; Poireau, V.

Using the entire sample of 467x10{sup 6} {Upsilon}(4S){yields}BB decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at the SLAC National Accelerator Laboratory, we perform an analysis of B{sup {+-}}{yields}DK{sup {+-}}decays, using decay modes in which the neutral D meson decays to either CP-eigenstates or non-CP-eigenstates. We measure the partial decay rate charge asymmetries for CP-even and CP-odd D final states to be A{sub CP+}=0.25{+-}0.06{+-}0.02 and A{sub CP-}=-0.09{+-}0.07{+-}0.02, respectively, where the first error is the statistical and the second is the systematic uncertainty. The parameter A{sub CP+} is different from zero with a significance of 3.6 standardmore » deviations, constituting evidence for direct CP violation. We also measure the ratios of the charged-averaged B partial decay rates in CP and non-CP decays, R{sub CP+}=1.18{+-}0.09{+-}0.05 and R{sub CP-}=1.07{+-}0.08{+-}0.04. We infer frequentist confidence intervals for the angle {gamma} of the unitarity triangle, for the strong phase difference {delta}{sub B}, and for the amplitude ratio r{sub B}, which are related to the B{sup -}{yields}DK{sup -} decay amplitude by r{sub B}e{sup i({delta}{sub B}-{gamma})}=A(B{sup -}{yields}D{sup 0}K{sup -})/A(B{sup -}{yields}D{sup 0}K{sup -}). Including statistical and systematic uncertainties, we obtain 0.24

Subprimal purchasing and merchandising decisions for pork: relationship to retail yield and fabrication time.

PubMed

Lorenzen, C L; Griffin, D B; Dockerty, T R; Walter, J P; Johnson, H K; Savell, J W

1996-01-01

Boxed pork was obtained to represent four different purchase specifications (different anatomical separation locations and[or] external fat trim levels) common in the pork industry to conduct a study of retail yields and labor requirements. Bone-in loins (n = 180), boneless loins (n = 94), and Boston butts (n = 148) were assigned randomly to fabrication styles within subprimals. When comparing cutting styles within subprimals, it was evident that cutting style affected percentage of retail yield and cutting time. When more bone-in cuts were prepared from bone-in loin subprimals, retail yields ranged from 92.80 +/- .61 to 95.28 +/- .45%, and processing times ranged from 222.57 +/- 10.13 to 318.99 +/- 7.85 s, from the four suppliers. When more boneless cuts were prepared from bone-in loin subprimals, retail yields ranged from 71.12 +/- 1.10 to 77.92 +/- .77% and processing times ranged from 453.49 +/- 8.95 to 631.09 +/- 15.04 s from the different loins. Comparing boneless to bone-in cuts from bone-in loins resulted in lower yields and required greater processing times. Significant variations in yields and times were found within cutting styles. These differences seemed to have been the result of variation in supplier fat trim level and anatomical separation (primarily scribe length).

Estimating the Impact and Spillover Effect of Climate Change on Crop Yield in Northern Ghana.

NASA Astrophysics Data System (ADS)

Botchway, E.

2016-12-01

In tropical regions of the world human-induced climate change is likely to impact negatively on crop yields. To investigate the impact of climate change and its spillover effect on mean and variance of crop yields in northern Ghana, the Just and Pope stochastic production function and the Spatial Durbin model were adopted. Surprisingly, the results suggest that both precipitation and average temperature have positive effects on mean crop yield during the wet season. Wet season average temperature has a significant spillover effect in the region, whereas precipitation during the wet season has only one significant spillover effect on maize yield. Wet season precipitation does not have a strong significant effect on crop yield despite the rainfed nature of agriculture in the region. Thus, even if there are losers and winners as a result of future climate change at the regional level, future crop yield would largely depend on future technological development in agriculture, which may improve yields over time despite the changing climate. We argue, therefore, that technical improvement in farm management such as improved seeds and fertilizers, conservation tillage and better pest control, may have a more significant role in increasing observed crop productivity levels over time. So investigating the relative importance of non-climatic factors on crop yield may shed more light on where appropriate interventions can help in improving crop yields. Climate change, also, needs to be urgently assessed at the level of the household, so that poor and vulnerable people dependent on agriculture can be appropriately targeted in research and development activities whose object is poverty alleviation.

Recent trends in vegetation greenness in China significantly altered annual evapotranspiration and water yield

NASA Astrophysics Data System (ADS)

Liu, Y.; Xiao, J.

2017-12-01

There has been growing evidence that vegetation greenness has been increasing in many parts of the northern middle and high latitudes including China during the last three to four decades. However, the effects of vegetation greening particularly afforestation on the hydrologic cycle have been controversial. We used a process-based ecosystem model and a satellite-derived leaf area index (LAI) dataset to examine how the changes in vegetation greenness affected annual evapotranspiration (ET) and water yield for China over the period from 2000 to 2014. Significant trends in vegetation greenness were observed in 26.1% of China's land area. We used two model simulations driven with original and detrended LAI, respectively, to assess the effects of vegetation greening and browning on terrestrial ET and water yield. On a per-pixel basis, vegetation greening increased annual ET and decreased water yield or weakened the increase in water yield; vegetation browning reduced ET and increased water yield or weakened the decrease in water yield. At the large river basin and national scales, the greening trends had positive effects on annual ET and had negative effects on water yield. Our results showed that the effects of the greenness changes on ET and water yield varied with spatial scale. Afforestation efforts perhaps should focus on southern China with larger water supply given the water crisis in northern China and the negative effects of vegetation greening on water yield. Future studies on the effects of the greenness changes on the hydrologic cycle are needed to account for the feedbacks to the climate.

Fragile-to-strong transition in liquid silica

NASA Astrophysics Data System (ADS)

Geske, Julian; Drossel, Barbara; Vogel, Michael

2016-03-01

We investigate anomalies in liquid silica with molecular dynamics simulations and present evidence for a fragile-to-strong transition at around 3100 K-3300 K. To this purpose, we studied the structure and dynamical properties of silica over a wide temperature range, finding four indicators of a fragile-to-strong transition. First, there is a density minimum at around 3000 K and a density maximum at 4700 K. The turning point is at 3400 K. Second, the local structure characterized by the tetrahedral order parameter changes dramatically around 3000 K from a higher-ordered, lower-density phase to a less ordered, higher-density phase. Third, the correlation time τ changes from an Arrhenius behavior below 3300 K to a Vogel-Fulcher-Tammann behavior at higher temperatures. Fourth, the Stokes-Einstein relation holds for temperatures below 3000 K, but is replaced by a fractional relation above this temperature. Furthermore, our data indicate that dynamics become again simple above 5000 K, with Arrhenius behavior and a classical Stokes-Einstein relation.

Evidence for glaciation in Elysium

NASA Technical Reports Server (NTRS)

Anderson, Duwayne M.; Brandstrom, Gary W.

1987-01-01

It is suggested that certain landforms in the Elysium region of Mars provide strong evidence for glaciation. Landscapes related to subglacial volcanism suggest that ice was a primary agent in the development of Elysium.

High-resolution mapping of yield curve shape and evolution for high porosity sandstones

NASA Astrophysics Data System (ADS)

Bedford, J. D.; Faulkner, D.; Wheeler, J.; Leclere, H.

2017-12-01

The onset of permanent inelastic deformation for porous rock is typically defined by a yield curve plotted in P-Q space, where P is the effective mean stress and Q is the differential stress. Sandstones usually have broadly elliptical shaped yield curves, with the low pressure side of the ellipse associated with localized brittle faulting (dilation) and the high pressure side with distributed ductile deformation (compaction). However recent works have shown that these curves might not be perfectly elliptical and that significant evolution in shape occurs with continued deformation. We therefore use a novel stress-probing methodology to map in high-resolution the yield curve shape for Boise and Idaho Gray sandstones (36-38% porosity) and also investigate curve evolution with increasing deformation. The data reveal yield curves with a much flatter geometry than previously recorded for porous sandstone and that the compactive side of the curve is partly comprised of a near vertical limb. The yield curve evolution is found to be strongly dependent on the nature of inelastic strain. Samples that were compacted under a deviatoric load, with a component of inelastic shear strain, were found to have yield curves with peaks that are approximately 50% higher than similar porosity samples that were hydrostatically compacted (i.e. purely volumetric strain). The difference in yield curve evolution along the different loading paths is attributed to mechanical anisotropy that develops during deviatoric loading by the closure of preferentially orientated fractures. Increased shear strain also leads to the formation of a plateau at the peak of the yield curve as samples deform along the deviatoric loading path. These results have important implications for understanding how the strength of porous rock evolves along different stress paths, including during fluid extraction from hydrocarbon reservoirs where the stress state is rarely isotropic.

Estimates of spatial and temporal variation of energy crops biomass yields in the US

NASA Astrophysics Data System (ADS)

Song, Y.; Jain, A. K.; Landuyt, W.; Kheshgi, H. S.

2013-12-01

Perennial grasses, such as switchgrass (Panicum viragatum) and Miscanthus (Miscanthus x giganteus) have been identified for potential use as biomass feedstocks in the US. Current research on perennial grass biomass production has been evaluated on small-scale plots. However, the extent to which this potential can be realized at a landscape-scale will depend on the biophysical potential to grow these grasses with minimum possible amount of land that needs to be diverted from food to fuel production. To assess this potential three questions about the biomass yield for these grasses need to be answered: (1) how the yields for different grasses are varied spatially and temporally across the US; (2) whether the yields are temporally stable or not; and (3) how the spatial and temporal trends in yields of these perennial grasses are controlled by limiting factors, including soil type, water availability, climate, and crop varieties. To answer these questions, the growth processes of the perennial grasses are implemented into a coupled biophysical, physiological and biogeochemical model (ISAM). The model has been applied to quantitatively investigate the spatial and temporal trends in biomass yields for over the period 1980 -2010 in the US. The bioenergy grasses considered in this study include Miscanthus, Cave-in-Rock switchgrass and Alamo switchgrass. The effects of climate, soil and topography on the spatial and temporal trends of biomass yields are quantitatively analyzed using principal component analysis and GIS based geographically weighted regression. The spatial temporal trend results are evaluated further to classify each part of the US into four homogeneous potential yield zones: high and stable yield zone (HS), high but unstable yield zone (HU), low and stable yield zone (LS) and low but unstable yield zone (LU). Our preliminary results indicate that the yields for perennial grasses among different zones are strongly related to the different controlling factors

On selecting evidence to test hypotheses: A theory of selection tasks.

PubMed

Ragni, Marco; Kola, Ilir; Johnson-Laird, Philip N

2018-05-21

How individuals choose evidence to test hypotheses is a long-standing puzzle. According to an algorithmic theory that we present, it is based on dual processes: individuals' intuitions depending on mental models of the hypothesis yield selections of evidence matching instances of the hypothesis, but their deliberations yield selections of potential counterexamples to the hypothesis. The results of 228 experiments using Wason's selection task corroborated the theory's predictions. Participants made dependent choices of items of evidence: the selections in 99 experiments were significantly more redundant (using Shannon's measure) than those of 10,000 simulations of each experiment based on independent selections. Participants tended to select evidence corresponding to instances of hypotheses, or to its counterexamples, or to both. Given certain contents, instructions, or framings of the task, they were more likely to select potential counterexamples to the hypothesis. When participants received feedback about their selections in the "repeated" selection task, they switched from selections of instances of the hypothesis to selection of potential counterexamples. These results eliminated most of the 15 alternative theories of selecting evidence. In a meta-analysis, the model theory yielded a better fit of the results of 228 experiments than the one remaining theory based on reasoning rather than meaning. We discuss the implications of the model theory for hypothesis testing and for a well-known paradox of confirmation. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Impact of Thiamethoxam Seed Treatment on Growth and Yield of Rice, Oryza sativa.

PubMed

Lanka, S K; Senthil-Nathan, S; Blouin, D J; Stout, M J

2017-04-01

Neonicotinoid seed treatments are widely used in agriculture. In rice, Oryza sativa L., in the southern United States, neonicotinoid seed treatments are used to manage early-season populations of the rice water weevil, Lissorhoptrus oryzophilus Kuschel. In addition to their effects on pests, neonicotinoid seed treatments may benefit crop plants directly by increasing plant growth or altering plant responses to stresses. As part of an effort to assess the overall benefits of thiamethoxam seed treatment in rice, rice emergence, growth, and yield were evaluated. In a growth chamber, rice emergence from the soil was 1-2 d more rapid from treated than untreated seeds. These laboratory results were supported by field experiments that revealed higher stand counts from thiamethoxam-treated plots than from untreated plots. Yields from thiamethoxam treatments were no higher than those from untreated plots under conditions in which weevil larvae were absent, a result inconsistent with the hypothesis that thiamethoxam imparts direct yield benefits. In a series of field experiments conducted to compare the relationship between weevil larval densities and rice yields in plots treated with several rates of thiamethoxam or chlorantraniliprole (another widely used seed treatment insecticide), the relationship between weevil density and yield did not differ markedly among both seed treatments. Overall yields from both seed treatments did not differ significantly, despite more effective control in chlorantraniliprole-treated plots. These results provide strong support for effect of thiamethoxam on early-season growth of rice, but only weak support for its direct effect on rice yields. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Ozone Induced Premature Mortality and Crop Yield Loss in China

NASA Astrophysics Data System (ADS)

Lin, Y.; Jiang, F.; Wang, H.

2017-12-01

Exposure to ambient ozone is a major risk factor for health impacts such as chronic obstructive pulmonary disease (COPD) and cause damage to plant and agricultural crops. But these impacts were usually evaluated separately in earlier studies. We apply Community Multi-scale Air Quality model to simulate the ambient O3 concentration at a resolution of 36 km×36 km across China. Then, we follow Global Burden of Diseases approach and AOT40 (i.e., above a threshold of 40 ppb) metric to estimate the premature mortalities and yield losses of major grain crops (i.e., winter wheat, rice and corn) across China due to surface ozone exposure, respectively. Our results show that ozone exposure leads to nearly 67,700 premature mortalities and 145 billion USD losses in 2014. The ozone induced yield losses of all crop production totaled 78 (49.9-112.6)million metric tons, worth 5.3 (3.4-7.6)billion USD, in China. The relative yield losses ranged from 8.5-14% for winter wheat, 3.9-15% for rice, and 2.2-5.5% for maize. We can see that the top four health affected provinces (Sichuan, Henan, Shandong, Jiangsu) are also ranking on the winter wheat and rice crop yield loss. Our results provide further evidence that surface ozone pollution is becoming urgent air pollution in China, and have important policy implications for China to alleviate the impacts of air pollution.

Strong liquid-crystalline polymeric compositions

DOEpatents

Dowell, Flonnie

1993-01-01

Strong liquid-crystalline polymeric (LCP) compositions of matter. LCP backbones are combined with liquid crystalline (LC) side chains in a manner which maximizes molecular ordering through interdigitation of the side chains, thereby yielding materials which are predicted to have superior mechanical properties over existing LCPs. The theoretical design of LCPs having such characteristics includes consideration of the spacing distance between side chains along the backbone, the need for rigid sections in the backbone and in the side chains, the degree of polymerization, the length of the side chains, the regularity of the spacing of the side chains along the backbone, the interdigitation of side chains in sub-molecular strips, the packing of the side chains on one or two sides of the backbone to which they are attached, the symmetry of the side chains, the points of attachment of the side chains to the backbone, the flexibility and size of the chemical group connecting each side chain to the backbone, the effect of semiflexible sections in the backbone and the side chains, and the choice of types of dipolar and/or hydrogen bonding forces in the backbones and the side chains for easy alignment.

Strong liquid-crystalline polymeric compositions

DOEpatents

Dowell, F.

1993-12-07

Strong liquid-crystalline polymeric (LCP) compositions of matter are described. LCP backbones are combined with liquid crystalline (LC) side chains in a manner which maximizes molecular ordering through interdigitation of the side chains, thereby yielding materials which are predicted to have superior mechanical properties over existing LCPs. The theoretical design of LCPs having such characteristics includes consideration of the spacing distance between side chains along the backbone, the need for rigid sections in the backbone and in the side chains, the degree of polymerization, the length of the side chains, the regularity of the spacing of the side chains along the backbone, the interdigitation of side chains in sub-molecular strips, the packing of the side chains on one or two sides of the backbone to which they are attached, the symmetry of the side chains, the points of attachment of the side chains to the backbone, the flexibility and size of the chemical group connecting each side chain to the backbone, the effect of semiflexible sections in the backbone and the side chains, and the choice of types of dipolar and/or hydrogen bonding forces in the backbones and the side chains for easy alignment. 27 figures.

Infrasound Propagation Modeling for Explosive Yield Estimation

NASA Astrophysics Data System (ADS)

Howard, J. E.; Golden, P.; Negraru, P.

2013-12-01

This study focuses on developing methods of estimating the size or yield of HE surface explosions from local and regional infrasound measurements in the southwestern United States. A munitions disposal facility near Mina, Nevada provides a repeating ground-truth source for this study, with charge weights ranging from 870 - 3800 lbs. Detonation logs and GPS synchronized videos were obtained for a sample of shots representing the full range of weights. These are used to calibrate a relationship between charge weight and spectral level from seismic waveforms recorded at the Nevada Seismic Array (NVAR) at a distance of 36 km. Origin times and yields for the remaining shots are inferred from the seismic recordings at NVAR. Infrasound arrivals from the detonations have been continuously recorded on three four-element, small aperture infrasound arrays since late 2009. NVIAR is collocated with NVAR at a range of approximately 36 km to the northeast. FALN and DNIAR are located at ranges of 154 km to the north, and 293 km to the southeast respectively. Travel times and amplitudes for stratospheric arrivals at DNIAR show strong seasonal variability with the largest amplitudes and celerities occurring during the winter months when the stratospheric winds are favorable. Stratospheric celerities for FNIAR to the north are more consistent as they are not strongly affected by the predominantly meridional stratospheric winds. Tropospheric arrivals at all three arrays show considerable variability that does not appear to be a seasonal effect. Naval Research Laboratory Ground to Space (NRL-G2S) Mesoscale models are used to specify the atmosphere along the propagation path for each detonation. Ray-tracing is performed for each source/receiver pair to identify events for which the models closely match the travel-time observations. This subset of events is used to establish preliminary wind correction formulas using wind values from the G2S profile for the entire propagation path. These

A Correlation Between Length of Strong-Shear Neutral Lines and Total X-Ray Brightness in Active Regions

NASA Technical Reports Server (NTRS)

Falconer, D. A.

1997-01-01

From a sample of 7 MSFC vector magnetograms,of active regions and 17 Yohkoh SXT soft X-ray images of these active regions, we have found that the total x-ray brightness of an entire active region is correlated with the total length of neutral lines on which the magnetic field is both strong (less than 250 G) and strongly sheared (shear angle greater than 75 deg) in the same active region. This correlation, if not fortuitous, is additional evidence of the importance of strong-shear strong-field neutral lines to strong heating in active regions.

Evidence of parasexual activity in "asexual amoebae" Cochliopodium spp. (Amoebozoa): extensive cellular and nuclear fusion.

PubMed

Tekle, Yonas I; Anderson, O Roger; Lecky, Ariel F

2014-09-01

The majority of microbial eukaryotes have long been considered asexual, though new evidence indicates sex, or sexual-like (parasexual) behaviors that deviate from the usual union of two gametes, among other variant aspects. Over a dozen amoebozoans are implicated to have sexual stages. However, the exact mechanism by which sex occurs in these lineages remains elusive. This is mainly due to the diverse quality and cryptic nature of their life cycle. In this study we present evidence of some previously unreported aspects of the life cycle of an amoeba, Cochliopodium, that undergoes unusual intraspecific interactions using light microscopy and immunocytochemistry. Similar to other amoebozoans, Cochliopodium, is considered asexual with no published reports of sex or parasexuality. We also investigated environmental conditions that govern the observed intraspecific interactions. Both light microscopic and immunocytochemistry evidence demonstrates Cochliopodium undergoes cellular fusion (plasmogamy) and nuclear fusion (karyogamy). Large plasmodia eventually undergo karyogamy and contain large fused, polyploid, nuclei. These are observed to fragment, subsequently, by karyotomy (nuclear fission) and cytoplasmic fission to yield uninucleated amoebae. This process could lead to a non-meiotic, parasexual exchange of chromosomes in Cochliopodium. These findings strongly suggest that Cochliopodium is involved in parasexual activity and should no longer be considered strictly asexual. Copyright © 2014 Elsevier GmbH. All rights reserved.

IQs Are Very Strong but Imperfect Indicators of Psychometric "g": Results from Joint Confirmatory Factor Analysis

ERIC Educational Resources Information Center

Farmer, Ryan L.; Floyd, Randy G.; Reynolds, Matthew R.; Kranzler, John H.

2014-01-01

The most global score yielded by intelligence tests, IQs, are supported by substantial validity evidence and have historically been central to the identification of intellectual disabilities, learning disabilities, and giftedness. This study examined the extent to which IQs measure the ability they target, psychometric "g." Data from…

Directional x-ray dark-field imaging of strongly ordered systems

NASA Astrophysics Data System (ADS)

Jensen, Torben Haugaard; Bech, Martin; Zanette, Irene; Weitkamp, Timm; David, Christian; Deyhle, Hans; Rutishauser, Simon; Reznikova, Elena; Mohr, Jürgen; Feidenhans'L, Robert; Pfeiffer, Franz

2010-12-01

Recently a novel grating based x-ray imaging approach called directional x-ray dark-field imaging was introduced. Directional x-ray dark-field imaging yields information about the local texture of structures smaller than the pixel size of the imaging system. In this work we extend the theoretical description and data processing schemes for directional dark-field imaging to strongly scattering systems, which could not be described previously. We develop a simple scattering model to account for these recent observations and subsequently demonstrate the model using experimental data. The experimental data includes directional dark-field images of polypropylene fibers and a human tooth slice.

A systematic review of evidence for education and training interventions in microsurgery.

PubMed

Ghanem, Ali M; Hachach-Haram, Nadine; Leung, Clement Chi Ming; Myers, Simon Richard

2013-07-01

Over the past decade, driven by advances in educational theory and pressures for efficiency in the clinical environment, there has been a shift in surgical education and training towards enhanced simulation training. Microsurgery is a technical skill with a steep competency learning curve on which the clinical outcome greatly depends. This paper investigates the evidence for educational and training interventions of traditional microsurgical skills courses in order to establish the best evidence practice in education and training and curriculum design. A systematic review of MEDLINE, EMBASE, and PubMed databases was performed to identify randomized control trials looking at educational and training interventions that objectively improved microsurgical skill acquisition, and these were critically appraised using the BestBETs group methodology. The databases search yielded 1,148, 1,460, and 2,277 citations respectively. These were then further limited to randomized controlled trials from which abstract reviews reduced the number to 5 relevant randomised controlled clinical trials. The best evidence supported a laboratory based low fidelity model microsurgical skills curriculum. There was strong evidence that technical skills acquired on low fidelity models transfers to improved performance on higher fidelity human cadaver models and that self directed practice leads to improved technical performance. Although there is significant paucity in the literature to support current microsurgical education and training practices, simulated training on low fidelity models in microsurgery is an effective intervention that leads to acquisition of transferable skills and improved technical performance. Further research to identify educational interventions associated with accelerated skill acquisition is required.

Yield: it's now an entitlement

NASA Astrophysics Data System (ADS)

George, Bill

1994-09-01

Only a few years ago, the primary method of cost reduction and productivity improvement in the semiconductor industry was increasing manufacturing yields throughout the process. Many of the remarkable reliability improvements realized over the past decade have come about as a result of actions that were originally taken primarily to improve device yields. Obviously, the practice of productivity improvement through yield enhancement is limited to the attainment of 100% yield, at which point some other mechanism must be employed. Traditionally, new products have been introduced to manufacturing at a point of relative immaturity, and semiconductor producers have relied on the traditional `learning curve' method of yield improvement to attain profitable levels of manufacturing yield. Recently, results of a survey of several fabs by a group of University of California at Berkeley researchers in the Competitive Semiconductor Manufacturing Program indicate that most factories learn at about the same rate after startup, in terms of both line yield and defectivity. If this is indeed generally true, then the most competitive factor is the one that starts with the highest yield, and it is difficult to displace a leader once his lead has been established. The two observations made above carry enormous implications for the semiconductor development or manufacturing professional. First, one must achieve very high yields in order to even play the game. Second, the achievement of competitive yields over time in the life of a factory is determined even before the factory is opened, in the planning and development phase. Third, and perhaps most uncomfortable for those of us who have relied on yield improvement as a cost driver, the winners of the nineties will find new levers to drive costs down, having already gotten the benefit of very high yield. This paper looks at the question of how the winners will achieve the critical measures of success, high initial yield and utilization

Distinct N2O yields of AOB and AOA driven ammonia oxidation across a range of Oregon forest soils

NASA Astrophysics Data System (ADS)

Tzanakakis, Vasileios; Dörsch, Peter; Taylor, Anne E.; Giguere, Andrew T.; Bakken, Lars R.; Bottomley, Peter J.; Myrold, David D.

2017-04-01

Ammonia oxidation, as the first and limiting step of nitrification, is a critical process in global N cycling and an important source of nitrous oxide (N2O). Previous studies reported strong contrasts in potential nitrification rates and niche separation of ammonia oxidizing bacteria (AOB) and archaea (AOA) in three acid Oregon forest soils depending on tree stands. In the present study we were interested in the potential contribution of AOB and AOA to nitrification-derived N2O in these soils. We performed soil slurry incubations amended with NH4+ and determined the specific N2O yields of AOB and AOA using inhibitor techniques. Despite large differences in edaphic factors, potential nitrification rates, and niche partitioning, AOB- and AOA-mediated nitrification displayed fairly stable and distinct N2O yields. The N2O yields ranged from 0.11 to 0.17% for AOB and from 0.03 to 0.08% for AOA, which is in agreement with findings of previous pure culture and soil studies. Nitrite accumulation was observed in only one soil, upon NH4+ stimulation of AOB growth, without showing any effect on the apparent N2O yield. The partitioning between AOB and AOA activity was strongly affected by soil pH and nitrogen status, but there was no effect of these variables on the group-specific N2O yield. Together, this suggests that N2O yields of different ammonia oxidizing microorganisms are under tight biochemical control and that the potential contribution of nitrification to N2O emission in acid forest soils can be predicted from AOB - AOA partitioning.

Field Measurements of Black Carbon Yields from Gas Flaring.

PubMed

Conrad, Bradley M; Johnson, Matthew R

2017-02-07

Black carbon (BC) emissions from gas flaring in the oil and gas industry are postulated to have critical impacts on climate and public health, but actual emission rates remain poorly characterized. This paper presents in situ field measurements of BC emission rates and flare gas volume-specific BC yields for a diverse range of flares. Measurements were performed during a series of field campaigns in Mexico and Ecuador using the sky-LOSA optical measurement technique, in concert with comprehensive Monte Carlo-based uncertainty analyses. Parallel on-site measurements of flare gas flow rate and composition were successfully performed at a subset of locations enabling direct measurements of fuel-specific BC yields from flares under field conditions. Quantified BC emission rates from individual flares spanned more than 4 orders of magnitude (up to 53.7 g/s). In addition, emissions during one notable ∼24-h flaring event (during which the plume transmissivity dropped to zero) would have been even larger than this maximum rate, which was measured as this event was ending. This highlights the likely importance of superemitters to global emission inventories. Flare gas volume-specific BC yields were shown to be strongly correlated with flare gas heating value. A newly derived correlation fitting current field data and previous lab data suggests that, in the context of recent studies investigating transport of flare-generated BC in the Arctic and globally, impacts of flaring in the energy industry may in fact be underestimated.

Will reducing sugar-sweetened beverage consumption reduce obesity? Evidence supporting conjecture is strong, but evidence when testing effect is weak

PubMed Central

Kaiser, Kathryn A.; Shikany, James M.; Keating, Karen D.; Allison, David B.

2014-01-01

We provide arguments to the debate question and update a previous meta-analysis with recently published studies on effects of sugar-sweetened beverages (SSBs) on body weight/composition indices (BWIs). We abstracted data from randomized controlled trials examining effects of consumption of SSBs on BWIs. Six new studies met these criteria: 1) human trials, 2) 3 weeks duration, 3) random assignment to conditions differing only in consumption of SSBs, and 4) including a BWI outcome. Updated meta-analysis of a total of seven studies that added SSBs to persons’ diets showed dose-dependent increases in weight. Updated meta-analysis of eight studies attempting to reduce SSB consumption showed an equivocal effect on BWIs in all randomized subjects. When limited to subjects overweight at baseline, meta-analysis showed a significant effect of roughly 0.25 standard deviations (more weight loss/less weight gain) relative to controls. Evidence to date is equivocal in showing that decreasing SSB consumption will reduce the prevalence of obesity. Although new evidence suggests that an effect may yet be demonstrable in some populations, the integrated effect size estimate remains very small and of equivocal statistical significance. Problems in this research area and suggestions for future research are highlighted. PMID:23742715

Strong coupling-like phenomenon in single metallic nanoparticle embedded in molecular J-aggregates

NASA Astrophysics Data System (ADS)

Feng, Xin; Wang, Chen; Ma, Hongjing; Chen, Yuanyuan; Duan, Gaoyan; Zhang, Pengfei; Song, Gang

2018-02-01

Strong coupling-like phenomenon between plasmonic cavities and emitters provides a new way to realize the quantum-like effect controlling at microscale/nanoscale. We investigate the strong coupling-like phenomenon in the structure of single metallic nanoparticle embedded in molecular J-aggregates by the classical simulation method and show that the size of the metallic nanoparticle and the oscillator strength of molecular J-aggregates impact the strong coupling-like phenomenon. The strong coupling-like phenomenon is induced by the interactions between two dipoles formed by the metallic nanoparticle and molecular J-aggregates or the interactions between the dipole generated from molecular J-aggregates and the quadrupole generated from the metallic nanoparticle. The strong coupling-like phenomenon appears evidently with the increase in oscillator strength of molecular J-aggregates. The detuning energy linearly decreases with the increase in radius of the metallic nanoparticle. Our structure has potential applications in quantum networks, quantum key distributions and so on.

Strong self-limitation promotes the persistence of rare species.

PubMed

Yenni, Glenda; Adler, Peter B; Ernest, S K Morgan

2012-03-01

Theory has recognized a combination of niche and neutral processes each contributing, with varying importance, to species coexistence. However, long-term persistence of rare species has been difficult to produce in trait-based models of coexistence that incorporate stochastic dynamics, raising questions about how rare species persist despite such variability. Following recent evidence that rare species may experience significantly different population dynamics than dominant species, we use a plant community model to simulate the effect of disproportionately strong negative frequency dependence on the long-term persistence of the rare species in a simulated community. This strong self-limitation produces long persistence times for the rare competitors, which otherwise succumb quickly to stochastic extinction. The results suggest that the mechanism causing species to be rare in this case is the same mechanism allowing those species to persist.

Ideal gas behavior of a strongly coupled complex (dusty) plasma.

PubMed

Oxtoby, Neil P; Griffith, Elias J; Durniak, Céline; Ralph, Jason F; Samsonov, Dmitry

2013-07-05

In a laboratory, a two-dimensional complex (dusty) plasma consists of a low-density ionized gas containing a confined suspension of Yukawa-coupled plastic microspheres. For an initial crystal-like form, we report ideal gas behavior in this strongly coupled system during shock-wave experiments. This evidence supports the use of the ideal gas law as the equation of state for soft crystals such as those formed by dusty plasmas.

Formation of Globular Clusters with Internal Abundance Spreads in r -Process Elements: Strong Evidence for Prolonged Star Formation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bekki, Kenji; Tsujimoto, Takuji

Several globular clusters (GCs) in the Galaxy are observed to show internal abundance spreads in r -process elements (e.g., Eu). We propose a new scenario that explains the origin of these GCs (e.g., M5 and M15). In this scenario, stars with no/little abundance variations first form from a massive molecular cloud (MC). After all of the remaining gas of the MC is expelled by numerous supernovae, gas ejected from asymptotic giant branch stars can be accumulated in the central region of the GC to form a high-density intracluster medium (ICM). Merging of neutron stars then occurs to eject r -processmore » elements, which can be efficiently trapped in and subsequently mixed with the ICM. New stars formed from the ICM can have r -process abundances that are quite different from those of earlier generations of stars within the GC. This scenario can explain both (i) why r -process elements can be trapped within GCs and (ii) why GCs with internal abundance spreads in r -process elements do not show [Fe/H] spreads. Our model shows (i) that a large fraction of Eu-rich stars can be seen in Na-enhanced stellar populations of GCs, as observed in M15, and (ii) why most of the Galactic GCs do not exhibit such internal abundance spreads. Our model demonstrates that the observed internal spreads of r -process elements in GCs provide strong evidence for prolonged star formation (∼10{sup 8} yr).« less

Identifying seedling root architectural traits associated with yield and yield components in wheat.

PubMed

Xie, Quan; Fernando, Kurukulasuriya M C; Mayes, Sean; Sparkes, Debbie L

2017-05-01

Plant roots growing underground are critical for soil resource acquisition, anchorage and plant-environment interactions. In wheat ( Triticum aestivum ), however, the target root traits to improve yield potential still remain largely unknown. This study aimed to identify traits of seedling root system architecture (RSA) associated with yield and yield components in 226 recombinant inbred lines (RILs) derived from a cross between the bread wheat Triticum aestivum 'Forno' (small, wide root system) and spelt Triticum spelta 'Oberkulmer' (large, narrow root system). A 'pouch and wick' high-throughput phenotyping pipeline was used to determine the RSA traits of 13-day-old RIL seedlings. Two field experiments and one glasshouse experiment were carried out to investigate the yield, yield components and phenology, followed by identification of quantitative trait loci (QTLs). There was substantial variation in RSA traits between genotypes. Seminal root number and total root length were both positively associated with grains m -2 , grains per spike, above-ground biomass m -2 and grain yield. More seminal roots and longer total root length were also associated with delayed maturity and extended grain filling, likely to be a consequence of more grains being defined before anthesis. Additionally, the maximum width of the root system displayed positive relationships with spikes m -2 , grains m -2 and grain yield. Ten RILs selected for the longest total roots exhibited the same effects on yield and phenology as described above, compared with the ten lines with the shortest total roots. Genetic analysis revealed 38 QTLs for the RSA, and QTL coincidence between the root and yield traits was frequently observed, indicating tightly linked genes or pleiotropy, which concurs with the results of phenotypic correlation analysis. Based on the results from the Forno × Oberkulmer population, it is proposed that vigorous early root growth, particularly more seminal roots and longer total

Measurements of branching fraction ratios and CP-asymmetries in suppressed B{sup -}{yields}D({yields}K{sup +}{pi}{sup -})K{sup -} and B{sup -}{yields}D({yields}K{sup +}{pi}{sup -}){pi}{sup -} decays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aaltonen, T.; Brucken, E.; Devoto, F.

2011-11-01

We report the first reconstruction in hadron collisions of the suppressed decays B{sup -}{yields}D({yields}K{sup +}{pi}{sup -})K{sup -} and B{sup -}{yields}D({yields}K{sup +}{pi}{sup -}){pi}{sup -}, sensitive to the Cabibbo-Kobayashi-Maskawa phase {gamma}, using data from 7 fb{sup -1} of integrated luminosity collected by the CDF II detector at the Tevatron collider. We reconstruct a signal for the B{sup -}{yields}D({yields}K{sup +}{pi}{sup -})K{sup -} suppressed mode with a significance of 3.2 standard deviations, and measure the ratios of the suppressed to favored branching fractions R(K)=[22.0{+-}8.6(stat){+-}2.6(syst)]x10{sup -3}, R{sup +}(K)=[42.6{+-}13.7(stat){+-}2.8(syst)]x10{sup -3}, R{sup -}(K)=[3.8{+-}10.3(stat){+-}2.7(syst)]x10{sup -3} as well as the direct CP-violating asymmetry A(K)=-0.82{+-}0.44(stat){+-}0.09(syst) of this mode. Corresponding quantitiesmore » for B{sup -}{yields}D({yields}K{sup +}{pi}{sup -}){pi}{sup -} decay are also reported.« less

A reassessment of ground water flow conditions and specific yield at Borden and Cape Cod

USGS Publications Warehouse

Grimestad, Garry

2002-01-01

Recent widely accepted findings respecting the origin and nature of specific yield in unconfined aquifers rely heavily on water level changes observed during two pumping tests, one conducted at Borden, Ontario, Canada, and the other at Cape Cod, Massachusetts. The drawdown patterns observed during those tests have been taken as proof that unconfined specific yield estimates obtained from long-duration pumping tests should approach the laboratory-estimated effective porosity of representative aquifer formation samples. However, both of the original test reports included direct or referential descriptions of potential supplemental sources of pumped water that would have introduced intractable complications and errors into straightforward interpretations of the drawdown observations if actually present. Searches for evidence of previously neglected sources were performed by screening the original drawdown observations from both locations for signs of diagnostic skewing that should be present only if some of the extracted water was derived from sources other than main aquifer storage. The data screening was performed using error-guided computer assisted fitting techniques, capable of accurately sensing and simulating the effects of a wide range of non-traditional and external sources. The drawdown curves from both tests proved to be inconsistent with traditional single-source pumped aquifer models but consistent with site-specific alternatives that included significant contributions of water from external sources. The corrected pumping responses shared several important features. Unsaturated drainage appears to have ceased effectively at both locations within the first day of pumping, and estimates of specific yield stabilized at levels considerably smaller than the corresponding laboratory-measured or probable effective porosity. Separate sequential analyses of progressively later field observations gave stable and nearly constant specific yield estimates for each

Yield Behavior of Solution Treated and Aged Ti-6Al-4V

NASA Technical Reports Server (NTRS)

Ring, Andrew J.; Baker, Eric H.; Salem, Jonathan A.; Thesken, John C.

2014-01-01

Post yield uniaxial tension-compression tests were run on a solution treated and aged (STA), titanium 6-percent aluminum 4-percent vanadium (Ti-6Al-4V) alloy to determine the yield behavior on load reversal. The material exhibits plastic behavior almost immediately on load reversal implying a strong Bauschinger effect. The resultant stress-strain data was compared to a 1D mechanics model and a finite element model used to design a composite overwrapped pressure vessel (COPV). Although the models and experimental data compare well for the initial loading and unloading in the tensile regime, agreement is lost in the compressive regime due to the Bauschinger effect and the assumption of perfect plasticity. The test data presented here are being used to develop more accurate cyclic hardening constitutive models for future finite element design analysis of COPVs.

Risks, Outcomes, and Evidence-Based Interventions for Girls in the US Juvenile Justice System.

PubMed

Leve, Leslie D; Chamberlain, Patricia; Kim, Hyoun K

2015-09-01

The proportion of the juvenile justice population that comprises females is increasing, yet few evidence-based models have been evaluated and implemented with girls in the juvenile justice system. Although much is known about the risk and protective factors for girls who participate in serious delinquency, significant gaps in the research base hamper the development and implementation of theoretically based intervention approaches. In this review, we first summarize the extant empirical work about the predictors and sequelae of juvenile justice involvement for girls. Identified risk and protective factors that correspond to girls' involvement in the juvenile justice system have been shown to largely parallel those of boys, although exposure rates and magnitudes of association sometimes differ by sex. Second, we summarize findings from empirically validated, evidence-based interventions for juvenile justice-involved youths that have been tested with girls. The interventions include Functional Family Therapy, Multisystemic Therapy, Multidimensional Family Therapy, and Treatment Foster Care Oregon (formerly known as Multidimensional Treatment Foster Care). We conclude that existing evidence-based practices appear to be effective for girls. However, few studies have been sufficiently designed to permit conclusions about whether sex-specific interventions would yield any better outcomes for girls than would interventions that already exist for both sexes and that have a strong base of evidence to support them. Third, we propose recommendations for feasible, cost-efficient next steps to advance the research and intervention agendas for this under-researched and underserved population of highly vulnerable youths.

One-electron reduced density matrices of strongly correlated harmonium atoms.

PubMed

Cioslowski, Jerzy

2015-03-21

Explicit asymptotic expressions are derived for the reduced one-electron density matrices (the 1-matrices) of strongly correlated two- and three-electron harmonium atoms in the ground and first excited states. These expressions, which are valid at the limit of small confinement strength ω, yield electron densities and kinetic energies in agreement with the published values. In addition, they reveal the ω(5/6) asymptotic scaling of the exchange components of the electron-electron repulsion energies that differs from the ω(2/3) scaling of their Coulomb and correlation counterparts. The natural orbitals of the totally symmetric ground state of the two-electron harmonium atom are found to possess collective occupancies that follow a mixed power/Gaussian dependence on the angular momentum in variance with the simple power-law prediction of Hill's asymptotics. Providing rigorous constraints on energies as functionals of 1-matrices, these results are expected to facilitate development of approximate implementations of the density matrix functional theory and ensure their proper description of strongly correlated systems.

The Endocrine Society guidelines: when the confidence cart goes before the evidence horse.

PubMed

Brito, Juan P; Domecq, Juan P; Murad, Mohammed H; Guyatt, Gordon H; Montori, Victor M

2013-08-01

In 2005, the Endocrine Society (TES) adopted the GRADE system of developing clinical practice guidelines. Grading of Recommendations, Assessment, Development, and Evaluation working group guidance suggests that strong recommendations based on low or very low (L/VL) confidence may often be inappropriate, and has offered a taxonomy of paradigmatic situations in which strong recommendations based on L/VL confidence estimates may be appropriate. We sought to characterize strong recommendations of TES based on L/VL confidence evidence. We identified all strong recommendations based on L/VL confidence evidence published in TES guidelines between 2005 and 2011. We identified those consistent with one of the paradigmatic situations in the taxonomy. Two hundred six of 357 (58%) of the recommendations of TES were strong; of these, 121 (59%) were based on L/VL confidence evidence. Of these 121, 35 (29%) were consistent with one of the paradigmatic situations. The most common situation (13, 11%) was of a strong recommendation against the intervention because of low confidence evidence for benefit and high confidence evidence for harm. The remaining 86 (71%) comprised 43 (36%) "best practice" statements for which sensible alternatives do not exist; 5 (4%) in which recommendations were for "additional research"; 5 (4%) in which greater confidence in the estimates was warranted; and 33 (27%) for which we could not find a compelling explanation for the incongruence. Guideline panels should beware of formulating strong recommendations when confidence in estimates is low. Our taxonomy when such recommendations are appropriate may be helpful.

Closing the Yield Gap of Sugar Beet in the Netherlands-A Joint Effort.

PubMed

Hanse, Bram; Tijink, Frans G J; Maassen, Jurgen; van Swaaij, Noud

2018-01-01

The reform of the European Union's sugar regime caused potential decreasing beet prices. Therefore, the Speeding Up Sugar Yield (SUSY) project was initiated. At the start, a 3 × 15 target was formulated: in 2015 the national average sugar yield in the Netherlands equals 15 t/ha (60% of the sugar beet potential) and the total variable costs 15 euro/t sugar beet, aspiring a saving on total variable costs and a strong increase in sugar yield. Based on their average sugar yield in 2000-2004, 26 pairs of "type top" (high yielding) and "type average" (average yielding) growers were selected from all sugar beet growing regions in the Netherlands. On the fields of those farmers, all measures of sugar beet cultivation were investigated, including cost calculation and recording phytopathological, agronomical and soil characteristics in 2006 and 2007. Although there was no significant difference in total variable costs, the "type top" growers yielded significantly 20% more sugar in each year compared to the "type average" growers. Therefore, the most profitable strategy for the growers is maximizing sugar yield and optimizing costs. The difference in sugar yield between growers could be explained by pests and diseases (50%), weed control (30%), soil structure (25%) and sowing date (14%), all interacting with each other. The SUSY-project revealed the effect of the grower's management on sugar yield. As a follow up for the SUSY-project, a growers' guide "Suikerbietsignalen" was published, Best Practice study groups of growers were formed and trainings and workshops were given and field days organized. Further, the benchmarking and feedback on the crop management recordings and the extension on variety choice, sowing performance, foliar fungi control and harvest losses were intensified. On the research part, a resistance breaking strain of the Beet Necrotic Yellow Vein Virus (BNYVV) and a new foliar fungus, Stemphylium beticola , were identified and options for control were

Yield of reversible colloidal gels during flow start-up: release from kinetic arrest.

PubMed

Johnson, Lilian C; Landrum, Benjamin J; Zia, Roseanna N

2018-06-05

Yield of colloidal gels during start-up of shear flow is characterized by an overshoot in shear stress that accompanies changes in network structure. Prior studies of yield of reversible colloidal gels undergoing strong flow model the overshoot as the point at which network rupture permits fluidization. However, yield under weak flow, which is of interest in many biological and industrial fluids shows no such disintegration. The mechanics of reversible gels are influenced by bond strength and durability, where ongoing rupture and re-formation impart aging that deepens kinetic arrest [Zia et al., J. Rheol., 2014, 58, 1121], suggesting that yield be viewed as release from kinetic arrest. To explore this idea, we study reversible colloidal gels during start-up of shear flow via dynamic simulation, connecting rheological yield to detailed measurements of structure, bond dynamics, and potential energy. We find that pre-yield stress grows temporally with the changing roles of microscopic transport processes: early time behavior is set by Brownian diffusion; later, advective displacements permit relative particle motion that stretches bonds and stores energy. Stress accumulates in stretched, oriented bonds until yield, which is a tipping point to energy release, and is passed with a fully intact network, where the loss of very few bonds enables relaxation of many, easing glassy arrest. This is immediately followed by a reversal to growth in potential energy during bulk plastic deformation and condensation into larger particle domains, supporting the view that yield is an activated release from kinetic arrest. The continued condensation of dense domains and shrinkage of network surfaces, along with a decrease in the potential energy, permit the gel to evolve toward more complete phase separation, supporting our view that yield of weakly sheared gels is a 'non-equilibrium phase transition'. Our findings may be particularly useful for industrial or other coatings, where weak

Statistical Evaluations of Variations in Dairy Cows’ Milk Yields as a Precursor of Earthquakes

PubMed Central

Yamauchi, Hiroyuki; Hayakawa, Masashi; Asano, Tomokazu; Ohtani, Nobuyo; Ohta, Mitsuaki

2017-01-01

Simple Summary There are many reports of abnormal changes occurring in various natural systems prior to earthquakes. Unusual animal behavior is one of these abnormalities; however, there are few objective indicators and to date, reliability has remained uncertain. We found that milk yields of dairy cows decreased prior to an earthquake in our previous case study. In this study, we examined the reliability of decreases in milk yields as a precursor for earthquakes using long-term observation data. In the results, milk yields decreased approximately three weeks before earthquakes. We have come to the conclusion that dairy cow milk yields have applicability as an objectively observable unusual animal behavior prior to earthquakes, and dairy cows respond to some physical or chemical precursors of earthquakes. Abstract Previous studies have provided quantitative data regarding unusual animal behavior prior to earthquakes; however, few studies include long-term, observational data. Our previous study revealed that the milk yields of dairy cows decreased prior to an extremely large earthquake. To clarify whether the milk yields decrease prior to earthquakes, we examined the relationship between earthquakes of various magnitudes and daily milk yields. The observation period was one year. In the results, cross-correlation analyses revealed a significant negative correlation between earthquake occurrence and milk yields approximately three weeks beforehand. Approximately a week and a half beforehand, a positive correlation was revealed, and the correlation gradually receded to zero as the day of the earthquake approached. Future studies that use data from a longer observation period are needed because this study only considered ten earthquakes and therefore does not have strong statistical power. Additionally, we compared the milk yields with the subionospheric very low frequency/low frequency (VLF/LF) propagation data indicating ionospheric perturbations. The results showed

Variation of yield loci in finite element analysis by considering texture evolution for AA5042 aluminum sheets

NASA Astrophysics Data System (ADS)

Yoon, Jonghun; Kim, Kyungjin; Yoon, Jeong Whan

2013-12-01

Yield function has various material parameters that describe how materials respond plastically in given conditions. However, a significant number of mechanical tests are required to identify the many material parameters for yield function. In this study, an effective method using crystal plasticity through a virtual experiment is introduced to develop the anisotropic yield function for AA5042. The crystal plasticity approach was used to predict the anisotropic response of the material in order to consider a number of stress or strain modes that would not otherwise be evident through mechanical testing. A rate-independent crystal plasticity model based on a smooth single crystal yield surface, which removes the innate ambiguity problem within the rate-independent model and Taylor model for polycrystalline deformation behavior were employed to predict the material's response in the balanced biaxial stress, pure shear, and plane strain states to identify the parameters for the anisotropic yield function of AA5042.

Shear induced migration of particles in a yield stress fluid: experiment

NASA Astrophysics Data System (ADS)

Hormozi, Sarah; Gholami, Mohammad; Rashedi, Ahmadreza; Lenoir, Nicolas; Ovarlez, Guillaume

2017-11-01

We have performed rheometry coupled with X-ray radiography in a narrow gap Couette cell filled with a suspension of spherical particles in a yield stress fluid. In this setup, the shear rate is discontinuous changing from a constant value in the gap to zero in the reservoir located at the top. This shear rate inhomogeneity results in the migration of particles from the gap to the reservoir, so-called Shear Induced Migration (SIM). The rheometry results give us insight into understanding the bulk rheology in the presence of shear rate and solid volume fraction inhomogeneities. In addition to that, our recent X-ray radiography technique (Gholami et al., JOR. 2017) provides detailed information about the evolution of the solid volume fraction in the domain. These measurements allow us to refine the recent continuum model frameworks (Hormozi & Frigaard, JFM 2017) for SIM of particles in a yield stress suspending fluid. We show that complex rheology of the yield stress suspending fluid and formation of the islands of unyielded regions in the reservoir strongly affects the SIM of particles. This feature is absent when we deal with a Newtonian suspending fluid. NSF (Grant No. CBET-1554044- CAREER), ACS PRF (Grant No. 55661-DNI9).

Ultra-broadband nonlinear saturable absorption of high-yield MoS2 nanosheets

NASA Astrophysics Data System (ADS)

Wei, Rongfei; Zhang, Hang; Hu, Zhongliang; Qiao, Tian; He, Xin; Guo, Qiangbing; Tian, Xiangling; Chen, Zhi; Qiu, Jianrong

2016-07-01

High-yield MoS2 nanosheets with strong nonlinear optical (NLO) responses in a broad near-infrared range were synthesized by a facile hydrothermal method. The observation of saturable absorption, which was excited by the light with photon energy smaller than the gap energy of MoS2, can be attributed to the enhancement of the hybridization between the Mo d-orbital and S p-orbital by the oxygen incorporation into MoS2. High-yield MoS2 nanosheets with high modulation depth and large saturable intensity generated a stable, passively Q-switched fiber laser pulse at 1.56 μm. The high output power of 1.08 mW can be attained under a very low pump power of 30.87 mW. Compared to recently reported passively Q-switched fiber lasers utilizing exfoliated MoS2 nanosheets, the efficiency of the laser for our passive Q-switching operation is larger and reaches 3.50%. This research may extend the understanding on the NLO properties of MoS2 and indicate the feasibility of the high-yield MoS2 nanosheets to passively Q-switched fiber laser effectively at low pump strengths.

Long memory volatility of gold price returns: How strong is the evidence from distinct economic cycles?

NASA Astrophysics Data System (ADS)

Bentes, Sonia R.

2016-02-01

This paper examines the long memory behavior in the volatility of gold returns using daily data for the period 1985-2009. We divided the whole sample into eight sub-samples in order to analyze the robustness and consistency of our results during different crisis periods. This constitutes our main contribution. We cover four major world crises, namely, (i) the US stock market crash of 1987; (ii) the Asian financial crisis of 1997; (iii) the World Trade Center terrorist attack of 2001 and finally, (iv) the sub-prime crisis of 2007, in order to investigate how the fractional integrated parameter of the FIGARCH(1, d,1) model evolves over time. Our findings are twofold: (i) there is evidence of long memory in the conditional variance over the whole sample period; (ii) when we consider the sub-sample analysis, the results show mixed evidence. Thus, for the 1985-2003 period the long memory parameter is positive and statistically significant in the pre-crisis sub-samples, and there is no evidence of long memory in the crisis sub-sample periods; however the reverse pattern occurs for the 2005-2009 period. This highlights the unique characteristics of the 2007 sub-prime crisis.

Emerging Signs of Strong Reciprocity in Human Ontogeny

PubMed Central

Robbins, Erin; Rochat, Philippe

2011-01-01

Strong reciprocity is considered here as the propensity to sacrifice resources to be kind or to punish in response to prior acts, a behavior not simply reducible to self-interest and a likely force behind human cooperation and sociality. The aim was to capture emerging signs of strong reciprocity in human ontogeny and across highly contrasted cultures. Three- and 5-year-old middle class American children (N = 162) were tested in a simple, multiple round, three-way sharing game involving the child, a generous puppet, and a stingy puppet. At the end of the game, the child was offered an opportunity to sacrifice some of her personal gains to punish one of the puppets. By 3 years, American children demonstrate a willingness to engage in costly punishment. However, only 5-year-olds show some evidence of strong reciprocity by orienting their punishment systematically toward the stingy puppet. Further analyses and three additional control conditions demonstrate that such propensity is not simply reducible to (a) straight imitation, or (b) inequity aversion. To assess the relative universality of such development, a group of 5- to 6-year-old children from rural Samoa (N = 14) were tested and compared to age and gender-matched American children. Samoan children did not manifest the same propensity toward strong reciprocity. The results are interpreted as pointing to (1) the developmental emergence of an ethical stance between 3 and 5 years of age, and (2) that the expression of such stance by young children could depend on culture. PMID:22194730

Size-Dependent Biexciton Quantum Yields and Carrier Dynamics of Quasi-Two-Dimensional Core/Shell Nanoplatelets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ma, Xuedan; Diroll, Benjamin T.; Cho, Wooje

Quasi-two-dimensional nanoplatelets (NPLs) possess fundamentally different excitonic properties from zero-dimensional quantum dots. We study lateral size-dependent photon emission statistics and carrier dynamics of individual NPLs using second-order photon correlation (g( 2)(τ)) spectroscopy and photoluminescence (PL) intensity-dependent lifetime analysis. Room-temperature radiative lifetimes of NPLs can be derived from maximum PL intensity periods in PL time traces. It first decreases with NPL lateral size and then stays constant, deviating from the electric dipole approximation. Analysis of the PL time traces further reveals that the single exciton quantum yield in NPLs decreases with NPL lateral size and increases with protecting shell thickness, indicatingmore » the importance of surface passivation on NPL emission quality. Second-order photon correlation (g( 2)(τ)) studies of single NPLs show that the biexciton quantum yield is strongly dependent on the lateral size and single exciton quantum yield of the NPLs. In large NPLs with unity single exciton quantum yield, the corresponding biexciton quantum yield can reach unity. In conclusion, these findings reveal that by careful growth control and core–shell material engineering, NPLs can be of great potential for light amplification and integrated quantum photonic applications.« less

Size-Dependent Biexciton Quantum Yields and Carrier Dynamics of Quasi-Two-Dimensional Core/Shell Nanoplatelets

DOE PAGES

Ma, Xuedan; Diroll, Benjamin T.; Cho, Wooje; ...

2017-08-08

Quasi-two-dimensional nanoplatelets (NPLs) possess fundamentally different excitonic properties from zero-dimensional quantum dots. We study lateral size-dependent photon emission statistics and carrier dynamics of individual NPLs using second-order photon correlation (g( 2)(τ)) spectroscopy and photoluminescence (PL) intensity-dependent lifetime analysis. Room-temperature radiative lifetimes of NPLs can be derived from maximum PL intensity periods in PL time traces. It first decreases with NPL lateral size and then stays constant, deviating from the electric dipole approximation. Analysis of the PL time traces further reveals that the single exciton quantum yield in NPLs decreases with NPL lateral size and increases with protecting shell thickness, indicatingmore » the importance of surface passivation on NPL emission quality. Second-order photon correlation (g( 2)(τ)) studies of single NPLs show that the biexciton quantum yield is strongly dependent on the lateral size and single exciton quantum yield of the NPLs. In large NPLs with unity single exciton quantum yield, the corresponding biexciton quantum yield can reach unity. In conclusion, these findings reveal that by careful growth control and core–shell material engineering, NPLs can be of great potential for light amplification and integrated quantum photonic applications.« less

STRONG LENS TIME DELAY CHALLENGE. II. RESULTS OF TDC1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liao, Kai; Treu, Tommaso; Marshall, Phil

2015-02-10

We present the results of the first strong lens time delay challenge. The motivation, experimental design, and entry level challenge are described in a companion paper. This paper presents the main challenge, TDC1, which consisted of analyzing thousands of simulated light curves blindly. The observational properties of the light curves cover the range in quality obtained for current targeted efforts (e.g., COSMOGRAIL) and expected from future synoptic surveys (e.g., LSST), and include simulated systematic errors. Seven teams participated in TDC1, submitting results from 78 different method variants. After describing each method, we compute and analyze basic statistics measuring accuracy (ormore » bias) A, goodness of fit χ{sup 2}, precision P, and success rate f. For some methods we identify outliers as an important issue. Other methods show that outliers can be controlled via visual inspection or conservative quality control. Several methods are competitive, i.e., give |A| < 0.03, P < 0.03, and χ{sup 2} < 1.5, with some of the methods already reaching sub-percent accuracy. The fraction of light curves yielding a time delay measurement is typically in the range f = 20%-40%. It depends strongly on the quality of the data: COSMOGRAIL-quality cadence and light curve lengths yield significantly higher f than does sparser sampling. Taking the results of TDC1 at face value, we estimate that LSST should provide around 400 robust time-delay measurements, each with P < 0.03 and |A| < 0.01, comparable to current lens modeling uncertainties. In terms of observing strategies, we find that A and f depend mostly on season length, while P depends mostly on cadence and campaign duration.« less

Mapping quantitative trait loci for yield, yield components and morphological traits in an advanced backcross population between Oryza rufipogon and the Oryza sativa cultivar Jefferson.

PubMed

Thomson, M J; Tai, T H; McClung, A M; Lai, X-H; Hinga, M E; Lobos, K B; Xu, Y; Martinez, C P; McCouch, S R

2003-08-01

An advanced backcross population between an accession of Oryza rufipogon (IRGC 105491) and the U.S. cultivar Jefferson (Oryza sativa ssp. japonica) was developed to identify quantitative trait loci (QTLs) for yield, yield components and morphological traits. The genetic linkage map generated for this population consisted of 153 SSR and RFLP markers with an average interval size of 10.3 cM. Thirteen traits were examined, nine of which were measured in multiple environments. Seventy-six QTLs above an experiment-wise significance threshold of P<0.01 (corresponding to an interval mapping LOD>3.6 or a composite interval mapping LOD>3.9) were identified. For the traits measured in multiple environments, 47% of the QTLs were detected in at least two environments. The O. rufipogon allele was favorable for 53% of the yield and yield component QTLs, including loci for yield, grains per panicle, panicle length, and grain weight. Morphological traits related to the domestication process and/or weedy characteristics, including plant height, shattering, tiller type and awns, were found clustered on chromosomes 1 and 4. Comparisons to previous studies involving wild x cultivated crosses revealed O. rufipogon alleles with stable effects in multiple genetic backgrounds and environments, several of which have not been detected in studies between Oryza sativa cultivars, indicating potentially novel alleles from O. rufipogon. Some O. rufipogon-derived QTLs, however, were in similar regions as previously reported QTLs from Oryza sativa cultivars, providing evidence for conservation of these QTLs across the Oryza genus. In addition, several QTLs for grain weight, plant height, and flowering time were localized to putative homeologous regions in maize where QTLs for these traits have been previously reported, supporting the hypothesis of functional conservation of QTLs across the grasses.

The Universe Going Green: Extraordinarily Strong [OIII]5007 in Typical Dwarf Galaxies at z~3

NASA Astrophysics Data System (ADS)

Malkan, Matthew Arnold; Cohen, Daniel

2017-01-01

We constructed the average SEDs of U-dropout galaxies in the Subaru Deep Field. This sample contains more than 5000 Lyman-break galaxies at z~3. Their average near- and mid-IR colors were obtained by stacking JHK and IRAC imaging, in bins of stellar mass. At the lowest mass bins an increasingly strong excess flux is seen in the K filter. This excess can reach 1 magnitude in the broadband filter, and we attribute it to strong \\OIII $\\lambda{5007}$ line emission. The equivalent width is extraordinarily high, reaching almost 1000\\Ang\\ for the average z=3 galaxy at an i magnitude of 27. Such extreme [OIII] emission is very rare in the current epoch, only seen in a handful of metal-deficient dwarf starbursts sometimes referred to as ''Green Peas". In contrast, extreme [OIII]--strong enough to dominate the entire broad-band SED--was evidently the norm for faint galaxies at high redshift. We present evidence that these small but numerous galaxies were primarily responsible for the reionization of the Universe.

Slopes of $pi$-meson spectra in the K $Yields$ 3$pi$ decays (in Russian)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kapustnikov, A.A.

1973-12-01

The strong violation ( approximates 35%) of the rule DELTA T = 1/2 on the Dalitz piot for the K yields 3 pi decays is considered in the framework of the nonlinear realization of the chiral SU(2) x SU(2) symmetry. The Lagrangian without derivatives obtained previously is used to describe the contact weak K pi interaction. It is postulated that the enhancement of effects related to the electromagnetic mass differences of pi and K mesons in the K yields 3 pi amplitudes is due to the PCAC modification: partial delta A = constant pi (1 - 2 alpha lambda /supmore » 2/ KK). At alpha = 0.8 the predictions of the model are shown to coincide with the experiment. (auth)« less

Strong Cosmic Censorship

NASA Astrophysics Data System (ADS)

Isenberg, James

2017-01-01

The Hawking-Penrose theorems tell us that solutions of Einstein's equations are generally singular, in the sense of the incompleteness of causal geodesics (the paths of physical observers). These singularities might be marked by the blowup of curvature and therefore crushing tidal forces, or by the breakdown of physical determinism. Penrose has conjectured (in his `Strong Cosmic Censorship Conjecture`) that it is generically unbounded curvature that causes singularities, rather than causal breakdown. The verification that ``AVTD behavior'' (marked by the domination of time derivatives over space derivatives) is generically present in a family of solutions has proven to be a useful tool for studying model versions of Strong Cosmic Censorship in that family. I discuss some of the history of Strong Cosmic Censorship, and then discuss what is known about AVTD behavior and Strong Cosmic Censorship in families of solutions defined by varying degrees of isometry, and discuss recent results which we believe will extend this knowledge and provide new support for Strong Cosmic Censorship. I also comment on some of the recent work on ``Weak Null Singularities'', and how this relates to Strong Cosmic Censorship.

Evidence for Direct CP Violation in the Measurement of the Cabbibo-Kobayashi-Maskawa Angle {gamma} with B{sup {+-}}{yields}D(*)K{sup (*){+-}} Decays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Amo Sanchez, P. del; Lees, J. P.; Poireau, V.

2010-09-17

We report the measurement of the Cabibbo-Kobayashi-Maskawa CP-violating angle {gamma} through a Dalitz plot analysis of neutral D-meson decays to K{sub S}{sup 0}{pi}{sup +}{pi}{sup -} and K{sub S}{sup 0}K{sup +}K{sup -} produced in the processes B{sup {+-}}{yields}DK{sup {+-}}, B{sup {+-}}{yields}D*K{sup {+-}} with D*{yields}D{pi}{sup 0}, D{gamma}, and B{sup {+-}}{yields}DK*{sup {+-}} with K*{sup {+-}}{yields}K{sub S}{sup 0}{pi}{+-}, using 468 million BB pairs collected by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at SLAC. We measure {gamma}=(68{+-}14{+-}4{+-}3) deg. (modulo 180 deg.), where the first error is statistical, the second is the experimental systematic uncertainty, and the third reflects the uncertaintymore » in the description of the neutral D decay amplitudes. This result is inconsistent with {gamma}=0 (no direct CP violation) with a significance of 3.5 standard deviations.« less

What Is the Role of Land-Use Compositions and Spatial Configurations in Sediment Yield from Mountainous Watershed?

NASA Astrophysics Data System (ADS)

Shi, Z. H.

2014-12-01

There are strong ties between land use and sediment yield in watersheds. Many studies have used multivariate regression techniques to explore the response of sediment yield to land-use compositions and spatial configurations in watersheds. However, one issue with the use of conventional statistical methods to address relationships between land-use compositions and spatial configurations and sediment yield is multicollinearity. This paper examines the combined effects of land-use compositions and land-use spatial configurations of the watershed on the specific sediment yield of the Upper Du River watershed (8,973 km2) in China using the Soil and Water Assessment Tool (SWAT) and partial least-squares regression (PLSR). The land-use compositions and spatial configurations of the watershed were calculated at the sub-watershed scale. The sediment yields from sub-watershed were evaluated using SWAT model. The first-order factors were identified by calculating the variable importance for the projection (VIP). The results revealed that the land-use compositions exerted the largest effects on the specific sediment yield and explained 61.2% of the variation in the specific sediment yield. Land-use spatial configurations were also found to have a large effect on the specific sediment yield and explained 21.7% of the observed variation in the specific sediment yield. The following are the dominant first-order factors of the specific sediment yield at the sub-watershed scale: the areal percentages of agriculture and forest, patch density, value of the Shannon's diversity index, contagion. The VIP values suggested that the Shannon's diversity index and contagion are important factors for sediment delivery.

Is red the colour of danger? Testing an implicit red-danger association.

PubMed

Pravossoudovitch, Karyn; Cury, Francois; Young, Steve G; Elliot, Andrew J

2014-01-01

Research using participant's self-reports has documented a link between red and danger. In this research, we used two different variants of a Stroop word evaluation task to test for the possibility of an implicit red-danger association using carefully controlled colour stimuli (equated on lightness and chroma). Experiment 1, using words as stimuli, yielded strong evidence of a link between red and danger, and weaker evidence of a green-safety association. Experiment 2, using symbols as stimuli, again yielded strong evidence of a link between red and danger; no green effects were observed. The findings were discussed in terms of the power and promise of red in signal communication.

Yield surface evolution for columnar ice

NASA Astrophysics Data System (ADS)

Zhou, Zhiwei; Ma, Wei; Zhang, Shujuan; Mu, Yanhu; Zhao, Shunpin; Li, Guoyu

A series of triaxial compression tests, which has capable of measuring the volumetric strain of the sample, were conducted on columnar ice. A new testing approach of probing the experimental yield surface was performed from a single sample in order to investigate yield and hardening behaviors of the columnar ice under complex stress states. Based on the characteristic of the volumetric strain, a new method of defined the multiaxial yield strengths of the columnar ice is proposed. The experimental yield surface remains elliptical shape in the stress space of effective stress versus mean stress. The effect of temperature, loading rate and loading path in the initial yield surface and deformation properties of the columnar ice were also studied. Subsequent yield surfaces of the columnar ice have been explored by using uniaxial and hydrostatic paths. The evolution of the subsequent yield surface exhibits significant path-dependent characteristics. The multiaxial hardening law of the columnar ice was established experimentally. A phenomenological yield criterion was presented for multiaxial yield and hardening behaviors of the columnar ice. The comparisons between the theoretical and measured results indicate that this current model is capable of giving a reasonable prediction for the multiaxial yield and post-yield properties of the columnar ice subjected to different temperature, loading rate and path conditions.

Prior Surgery Determines Islet Yield and Insulin Requirement in Patients with Chronic Pancreatitis

PubMed Central

Wang, Hongjun; Desai, Krupa D; Dong, Huansheng; Owzarski, Stefanie; Romagnuolo, Joseph; Morgan, Katherine A; Adams, David B

2013-01-01

Background Total pancreatectomy with islet autotransplantation (TP-IAT) is safe and effective in the management of intractable pain associated with chronic pancreatitis (CP). Prevention of pancreatogenic diabetes after TP-IAT is related to islet yield from the diseased pancreas. The purpose of this study is to compare islet yield and insulin requirement in the 76 patients who underwent different surgical procedures prior to TP-IAT at the Medical University of South Carolina between the years 2009 to 2011. Methods Patients were grouped into four categories based on the operation they had before TP-IAT: transduodenal sphincteroplasty or no prior surgery (TDS/NPS, n=50), Whipple or Beger procedure (WB, n=14), distal pancreatectomy (DP, n=8) or lateral pancreaticojejunostomy (LPJ, n=4). Islets were harvested from pancreases of those patients at our cGMP facility. Total unpurified islets were transplanted into patients via portal vein infusion. Pancreatic fibrosis, islet yield, cell viability and insulin requirement were measured. Results The pancreases of TDS/NPS and WB patients were less fibrotic, and had higher islet yield compared to those who had DP or LPJ. Higher islet yield also correlated with a greater diabetes free rate and a lesser insulin requirement at the following intervals: pre-operative, post-operative and 6 months after TP-IAT. Conclusions Prior surgery is strongly correlated with the extent of pancreatic fibrosis, islet yield and insulin requirements in CP patients undergoing TP-IAT. The history of prior pancreatic resection and drainage procedures may be used to predict post-operative islet function and help to determine the optimal timing for TP-IAT in CP patients. PMID:23411743

Evidence-based medicine and contemporary certification: Analysis of the American Board of Vascular Medicine endovascular board examination.

PubMed

Slovut, David Paul; Gray, Bruce H; Saiar, Amin; Bates, Mark C

2017-08-01

Since 2005, the American Board of Vascular Medicine (ABVM) endovascular examination has been used to certify vascular practitioners. Annual rigorous review has confirmed it is psychometrically valid and reliable. However, the evidence basis underlying the examination items has not been studied systematically. The aim of this study was to adjudicate class of recommendation (COR) and level of evidence (LOE) for the 2015 ABVM endovascular examination and establish an additional feedback mechanism for examination improvement based on contemporary evidence-based guidelines. We performed a pooled consensus process to classify each of the 110 items in the 2015 ABVM endovascular examination by COR and LOE as detailed in the current guideline statements. We added additional categories for items that were not eligible for assignment using traditional current evidence-based metrics: 'COR X', cannot be determined, not applicable, or simple recognition; and 'LOE X', cannot be determined or not applicable. COR classifications were assigned in the following proportion: Class I=15%, Class II=40%, Class III=3%, COR X=42%. LOE classifications were assigned in the following proportion: Level A=12%, Level B=34%, Level C=32%, LOE X=22%. Our analysis showed that nearly half of the 2015 ABVM endovascular examination items were supported by strong scientific evidence or fact-based knowledge. COR and LOE analysis yielded notably different results. Use of alternate classification schema may be powerful tools for improving certification exams in healthcare.

Identifying the Tunneling Site in Strong-Field Ionization of H_{2}^{+}.

PubMed

Liu, Kunlong; Barth, Ingo

2017-12-15

The tunneling site of the electron in a molecule exposed to a strong laser field determines the initial position of the ionizing electron and, as a result, has a large impact on the subsequent ultrafast electron dynamics on the polyatomic Coulomb potential. Here, the tunneling site of the electron of H_{2}^{+} ionized by a strong circularly polarized (CP) laser pulse is studied by numerically solving the time-dependent Schrödinger equation. We show that the electron removed from the down-field site is directly driven away by the CP field and the lateral photoelectron momentum distribution (LPMD) exhibits a Gaussian-like distribution, whereas the corresponding LPMD of the electron removed from the up-field site differs from the Gaussian shape due to the Coulomb focusing and scattering by the down-field core. Our current study presents the direct evidence clarifying a long-standing controversy over the tunneling site in H_{2}^{+} and raises the important role of the tunneling site in strong-field molecular ionization.

Predicting paddlefish roe yields using an extension of the Beverton–Holt equilibrium yield-per-recruit model

USGS Publications Warehouse

Colvin, M.E.; Bettoli, Phillip William; Scholten, G.D.

2013-01-01

Equilibrium yield models predict the total biomass removed from an exploited stock; however, traditional yield models must be modified to simulate roe yields because a linear relationship between age (or length) and mature ovary weight does not typically exist. We extended the traditional Beverton-Holt equilibrium yield model to predict roe yields of Paddlefish Polyodon spathula in Kentucky Lake, Tennessee-Kentucky, as a function of varying conditional fishing mortality rates (10-70%), conditional natural mortality rates (cm; 9% and 18%), and four minimum size limits ranging from 864 to 1,016mm eye-to-fork length. These results were then compared to a biomass-based yield assessment. Analysis of roe yields indicated the potential for growth overfishing at lower exploitation rates and smaller minimum length limits than were suggested by the biomass-based assessment. Patterns of biomass and roe yields in relation to exploitation rates were similar regardless of the simulated value of cm, thus indicating that the results were insensitive to changes in cm. Our results also suggested that higher minimum length limits would increase roe yield and reduce the potential for growth overfishing and recruitment overfishing at the simulated cm values. Biomass-based equilibrium yield assessments are commonly used to assess the effects of harvest on other caviar-based fisheries; however, our analysis demonstrates that such assessments likely underestimate the probability and severity of growth overfishing when roe is targeted. Therefore, equilibrium roe yield-per-recruit models should also be considered to guide the management process for caviar-producing fish species.

Projecting crop yield in northern high latitude area.

PubMed

Matsumura, Kanichiro

2014-01-01

Changing climatic conditions on seasonal and longer time scales influence agricultural production. Improvement of soil and fertilizer is a strong factor in agricultural production, but agricultural production is influenced by climate conditions even in highly developed countries. It is valuable if fewer predictors make it possible to conduct future projections. Monthly temperature and precipitation, wintertime 500hPa geopotential height, and the previous year's yield are used as predictors to forecast spring wheat yield in advance. Canadian small agricultural divisions (SAD) are used for analysis. Each SAD is composed of a collection of Canadian Agricultural Regions (CAR) of similar weather and growing conditions. Spring wheat yields in each CAR are forecast from the following variables: (a) the previous year's yield, (b) earlier stages of the growing season's climate conditions and, (c) the previous year's wintertime northern hemisphere 500hPa geopotential height field. Arctic outflow events in the Okanagan Valley in Canada are associated with episodes of extremely low temperatures during wintertime. Principal component analysis (PCA) is applied for wintertime northern hemisphere 500hPa geopotential height anomalies. The spatial PCA mode1 is defined as Arctic Oscillation and it influences prevailing westerlies. The prevailing westerlies meanders and influences climatic conditions. The spatial similarity between wintertime top 5 Arctic outflow event year's composites of 500hPa geopotential height anomalies and mode 3's spatial pattern is found. Mode 3's spatial pattern looks like the Pacific/North American (PNA) pattern which describes the variation of atmospheric circulation pattern over the Pacific Ocean and North America. Climate conditions from April to June, May to July, mode 3's time coefficients, and previous year's yield are used for forecasting spring wheat yield in each SAD. Cross-validation procedure which generates eight sets of models for the eight

Observational evidence of the complementary relationship in regional evaporation lends strong support for Bouchet's hypothesis

Treesearch

Jorge A. Ramirez; Michael T. Hobbins; Thomas C. Brown

2005-01-01

Using independent observations of actual and potential evapotranspiration at a wide range of spatial scales, we provide direct observational evidence of the complementary relationship in regional evapotranspiration hypothesized by Bouchet in 1963. Bouchet proposed that, for large homogeneous surfaces with minimal advection of heat and moisture, potential and actual...

Quantum Yield of Single Surface Plasmons Generated by a Quantum Dot Coupled with a Silver Nanowire.

PubMed

Li, Qiang; Wei, Hong; Xu, Hongxing

2015-12-09

The interactions between surface plasmons (SPs) in metal nanostructures and excitons in quantum emitters (QEs) lead to many interesting phenomena and potential applications that are strongly dependent on the quantum yield of SPs. The difficulty in distinguishing all the possible exciton recombination channels hinders the experimental determination of SP quantum yield. Here, we experimentally measured for the first time the quantum yield of single SPs generated by the exciton-plasmon coupling in a system composed of a single quantum dot and a silver nanowire (NW). By utilizing the SP guiding property of the NW, the decay rates of all the exciton recombination channels, i.e., direct free space radiation channel, SP generation channel, and nonradiative damping channel, are quantitatively obtained. It is determined that the optimum emitter-NW coupling distance for the largest SP quantum yield is about 10 nm, resulting from the different distance-dependent decay rates of the three channels. These results are important for manipulating the coupling between plasmonic nanostructures and QEs and developing on-chip quantum plasmonic devices for potential nanophotonic and quantum information applications.

On-line prediction of yield grade, longissimus muscle area, preliminary yield grade, adjusted preliminary yield grade, and marbling score using the MARC beef carcass image analysis system.

PubMed

Shackelford, S D; Wheeler, T L; Koohmaraie, M

2003-01-01

The present experiment was conducted to evaluate the ability of the U.S. Meat Animal Research Center's beef carcass image analysis system to predict calculated yield grade, longissimus muscle area, preliminary yield grade, adjusted preliminary yield grade, and marbling score under commercial beef processing conditions. In two commercial beef-processing facilities, image analysis was conducted on 800 carcasses on the beef-grading chain immediately after the conventional USDA beef quality and yield grades were applied. Carcasses were blocked by plant and observed calculated yield grade. The carcasses were then separated, with 400 carcasses assigned to a calibration data set that was used to develop regression equations, and the remaining 400 carcasses assigned to a prediction data set used to validate the regression equations. Prediction equations, which included image analysis variables and hot carcass weight, accounted for 90, 88, 90, 88, and 76% of the variation in calculated yield grade, longissimus muscle area, preliminary yield grade, adjusted preliminary yield grade, and marbling score, respectively, in the prediction data set. In comparison, the official USDA yield grade as applied by online graders accounted for 73% of the variation in calculated yield grade. The technology described herein could be used by the beef industry to more accurately determine beef yield grades; however, this system does not provide an accurate enough prediction of marbling score to be used without USDA grader interaction for USDA quality grading.

Genetic architecture of delayed senescence, biomass, and grain yield under drought stress in cowpea.

PubMed

Muchero, Wellington; Roberts, Philip A; Diop, Ndeye N; Drabo, Issa; Cisse, Ndiaga; Close, Timothy J; Muranaka, Satoru; Boukar, Ousmane; Ehlers, Jeffrey D

2013-01-01

The stay-green phenomenon is a key plant trait with wide usage in managing crop production under limited water conditions. This trait enhances delayed senescence, biomass, and grain yield under drought stress. In this study we sought to identify QTLs in cowpea (Vigna unguiculata) consistent across experiments conducted in Burkina Faso, Nigeria, Senegal, and the United States of America under limited water conditions. A panel of 383 diverse cowpea accessions and a recombinant inbred line population (RIL) were SNP genotyped using an Illumina 1536 GoldenGate assay. Phenotypic data from thirteen experiments conducted across the four countries were used to identify SNP-trait associations based on linkage disequilibrium association mapping, with bi-parental QTL mapping as a complementary strategy. We identified seven loci, five of which exhibited evidence suggesting pleiotropic effects (stay-green) between delayed senescence, biomass, and grain yield. Further, we provide evidence suggesting the existence of positive pleiotropy in cowpea based on positively correlated mean phenotypic values (0.34< r <0.87) and allele effects (0.07< r <0.86) for delayed senescence and grain yield across three African environments. Three of the five putative stay-green QTLs, Dro-1, 3, and 7 were identified in both RILs and diverse germplasm with resolutions of 3.2 cM or less for each of the three loci, suggesting that these may be valuable targets for marker-assisted breeding in cowpea. Also, the co-location of early vegetative delayed senescence with biomass and grain yield QTLs suggests the possibility of using delayed senescence at the seedling stage as a rapid screening tool for post-flowering drought tolerance in cowpea breeding. BLAST analysis using EST sequences harboring SNPs with the highest associations provided a genomic context for loci identified in this study in closely related common bean (Phaseolus vulgaris) and soybean (Glycine max) reference genomes.

Optomechanical Control of Quantum Yield in Trans-Cis Ultrafast Photoisomerization of a Retinal Chromophore Model.

PubMed

Valentini, Alessio; Rivero, Daniel; Zapata, Felipe; García-Iriepa, Cristina; Marazzi, Marco; Palmeiro, Raúl; Fdez Galván, Ignacio; Sampedro, Diego; Olivucci, Massimo; Frutos, Luis Manuel

2017-03-27

The quantum yield of a photochemical reaction is one of the most fundamental quantities in photochemistry, as it measures the efficiency of the transduction of light energy into chemical energy. Nature has evolved photoreceptors in which the reactivity of a chromophore is enhanced by its molecular environment to achieve high quantum yields. The retinal chromophore sterically constrained inside rhodopsin proteins represents an outstanding example of such a control. In a more general framework, mechanical forces acting on a molecular system can strongly modify its reactivity. Herein, we show that the exertion of tensile forces on a simplified retinal chromophore model provokes a substantial and regular increase in the trans-to-cis photoisomerization quantum yield in a counterintuitive way, as these extension forces facilitate the formation of the more compressed cis photoisomer. A rationale for the mechanochemical effect on this photoisomerization mechanism is also proposed. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Climate Change Impact Uncertainties for Maize in Panama: Farm Information, Climate Projections, and Yield Sensitivities

NASA Technical Reports Server (NTRS)

Ruane, Alex C.; Cecil, L. Dewayne; Horton, Radley M.; Gordon, Roman; McCollum, Raymond (Brown, Douglas); Brown, Douglas; Killough, Brian; Goldberg, Richard; Greeley, Adam P.; Rosenzweig, Cynthia

2011-01-01

We present results from a pilot project to characterize and bound multi-disciplinary uncertainties around the assessment of maize (Zea mays) production impacts using the CERES-Maize crop model in a climate-sensitive region with a variety of farming systems (Panama). Segunda coa (autumn) maize yield in Panama currently suffers occasionally from high water stress at the end of the growing season, however under future climate conditions warmer temperatures accelerate crop maturation and elevated CO (sub 2) concentrations improve water retention. This combination reduces end-of-season water stresses and eventually leads to small mean yield gains according to median projections, although accelerated maturation reduces yields in seasons with low water stresses. Calibrations of cultivar traits, soil profile, and fertilizer amounts are most important for representing baseline yields, however sensitivity to all management factors is reduced in an assessment of future yield changes (most dramatically for fertilizers), suggesting that yield changes may be more generalizable than absolute yields. Uncertainty around General Circulation Model (GCM)s' projected changes in rainfall gain in importance throughout the century, with yield changes strongly correlated with growing season rainfall totals. Climate changes are expected to be obscured by the large inter-annual variations in Panamanian climate that will continue to be the dominant influence on seasonal maize yield into the coming decades. The relatively high (A2) and low (B1) emissions scenarios show little difference in their impact on future maize yields until the end of the century. Uncertainties related to the sensitivity of CERES-Maize to carbon dioxide concentrations have a substantial influence on projected changes, and remain a significant obstacle to climate change impacts assessment. Finally, an investigation into the potential of simple statistical yield emulators based upon key climate variables characterizes the

Stress regularity in quasi-static perfect plasticity with a pressure dependent yield criterion

NASA Astrophysics Data System (ADS)

Babadjian, Jean-François; Mora, Maria Giovanna

2018-04-01

This work is devoted to establishing a regularity result for the stress tensor in quasi-static planar isotropic linearly elastic - perfectly plastic materials obeying a Drucker-Prager or Mohr-Coulomb yield criterion. Under suitable assumptions on the data, it is proved that the stress tensor has a spatial gradient that is locally squared integrable. As a corollary, the usual measure theoretical flow rule is expressed in a strong form using the quasi-continuous representative of the stress.

Three decades of monitoring in the Rio Cordon instrumented basin: Sediment budget and temporal trend of sediment yield

NASA Astrophysics Data System (ADS)

Rainato, R.; Mao, L.; García-Rama, A.; Picco, L.; Cesca, M.; Vianello, A.; Preciso, E.; Scussel, G. R.; Lenzi, M. A.

2017-08-01

This paper investigates nearly 30 years of monitoring of sediment fluxes in an instrumented Alpine basin (Rio Cordon, Italy). The collected bedload and suspended sediment transport data allows sediment dynamics to be analyzed at different time scales, ranging from short- (single event) to long-term (three decades). The Rio Cordon monitoring station has been operating since 1986, continuously recording water discharge, bedload and suspended load. At the flood event scale, a good relationship was found between peak discharges (Qpeak) and sediment load (bedload and suspended load). The inter-annual sediment yields were analyzed, also assessing the contribution of the single floods to the total sediment budget. The annual suspended load ranges from 10 to 2524 t yr- 1, while the bedload varies from 0 to 1543 t yr- 1. The higher annual yields were recorded in the years when large floods occurred, highlighting that the sediment budget in the Rio Cordon is strongly controlled by the occurrence of high magnitude events. Investigation of the seasonal suspended load contribution demonstrated that from 1986 to 1993 most fine sediments were transported during the snowmelt/summer seasons, while autumn and snowmelt were the dominant seasons contributing to sediment yield in the periods 1994-2002 and 2003-2014, respectively. The mean annual sediment yield from 1986 to 2014 is equal to 103 t km- 2 yr- 1, and overall, bedload accounts for 21% of the total sediment yield. The ratio between the sediment transport and the effective runoff of the events allowed the temporal trends of transport efficiency to be inferred, highlighting the existence of periods characterized by different sediment availability. In particular, despite no significant changes in the hydrological variables (i.e. rainfall), nearly a decade (1994-2002) with high transport efficiency appears to have occurred after an exceptional event (recurrence interval > 100 years). This event affected the sediment availability

Nanobiotechnology can boost crop production and quality: first evidence from increased plant biomass, fruit yield and phytomedicine content in bitter melon (Momordica charantia).

PubMed

Kole, Chittaranjan; Kole, Phullara; Randunu, K Manoj; Choudhary, Poonam; Podila, Ramakrishna; Ke, Pu Chun; Rao, Apparao M; Marcus, Richard K

2013-04-26

Recent research on nanoparticles in a number of crops has evidenced for enhanced germination and seedling growth, physiological activities including photosynthetic activity and nitrogen metabolism, mRNA expression and protein level, and also positive changes in gene expression indicating their potential use in crop improvement. We used a medicinally rich vegetable crop, bitter melon, as a model to evaluate the effects of seed treatment with a carbon-based nanoparticle, fullerol [C60(OH)20], on yield of plant biomass and fruit characters, and phytomedicine contents in fruits. We confirmed the uptake, translocation and accumulation of fullerol through bright field imaging and Fourier transform infra-red spectroscopy. We observed varied effects of seed treatment at five concentrations, including non-consequential and positive, on plant biomass yield, fruit yield and its component characters, and content of five phytomedicines in fruits. Fullerol-treatment resulted in increases up to 54% in biomass yield and 24% in water content. Increases of up to 20% in fruit length, 59% in fruit number, and 70% in fruit weight led to an improvement up to 128% in fruit yield. Contents of two anticancer phytomedicines, cucurbitacin-B and lycopene, were enhanced up to 74% and 82%, respectively, and contents of two antidiabetic phytomedicines, charantin and insulin, were augmented up to 20% and 91%, respectively. Non-significant correlation inter se plant biomass, fruit yield, phytomedicine content and water content evidenced for separate genetic control and biosynthetic pathways for production of plant biomass, fruits, and phytomedicines in fruits, and also no impact of increased water uptake. While our results indicated possibility of improving crop yield and quality by using proper concentrations of fullerol, extreme caution needs to be exercised given emerging knowledge about accumulation and toxicity of nanoparticles in bodily tissues.

Nanobiotechnology can boost crop production and quality: first evidence from increased plant biomass, fruit yield and phytomedicine content in bitter melon (Momordica charantia)

PubMed Central

2013-01-01

Background Recent research on nanoparticles in a number of crops has evidenced for enhanced germination and seedling growth, physiological activities including photosynthetic activity and nitrogen metabolism, mRNA expression and protein level, and also positive changes in gene expression indicating their potential use in crop improvement. We used a medicinally rich vegetable crop, bitter melon, as a model to evaluate the effects of seed treatment with a carbon-based nanoparticle, fullerol [C60(OH)20], on yield of plant biomass and fruit characters, and phytomedicine contents in fruits. Results We confirmed the uptake, translocation and accumulation of fullerol through bright field imaging and Fourier transform infra-red spectroscopy. We observed varied effects of seed treatment at five concentrations, including non-consequential and positive, on plant biomass yield, fruit yield and its component characters, and content of five phytomedicines in fruits. Fullerol-treatment resulted in increases up to 54% in biomass yield and 24% in water content. Increases of up to 20% in fruit length, 59% in fruit number, and 70% in fruit weight led to an improvement up to 128% in fruit yield. Contents of two anticancer phytomedicines, cucurbitacin-B and lycopene, were enhanced up to 74% and 82%, respectively, and contents of two antidiabetic phytomedicines, charantin and insulin, were augmented up to 20% and 91%, respectively. Non-significant correlation inter se plant biomass, fruit yield, phytomedicine content and water content evidenced for separate genetic control and biosynthetic pathways for production of plant biomass, fruits, and phytomedicines in fruits, and also no impact of increased water uptake. Conclusions While our results indicated possibility of improving crop yield and quality by using proper concentrations of fullerol, extreme caution needs to be exercised given emerging knowledge about accumulation and toxicity of nanoparticles in bodily tissues. PMID:23622112

Hemin-utilizing G-quadruplex DNAzymes are strongly active in organic co-solvents.

PubMed

Canale, Thomas D; Sen, Dipankar

2017-05-01

The widespread use of organic solvents in industrial processes has focused in recent years on the utility of "green" solvents - those with less harmful environmental, health, and safety properties - such as methanol and formamide. However, protein enzymes, regarded as green catalysts, are often incompatible with organic solvents. Herein, we have explored the oxidative properties of a Fe(III)-heme, or hemin, utilizing catalytic DNA (heme·DNAzyme) in different green solvent-water mixtures. We find that the peroxidase and peroxygenase activities of the heme·DNAzyme are strongly enhanced in 20-30% v/v methanol or formamide, relative to water alone. Protic solvent content of >30% v/v gradually diminishes heme·DNAzyme catalytic activity; however, the heme·DNAzyme is still active in as high as 80% v/v methanol. In contrast to protic solvents, aqueous dimethylformamide solutions largely inhibit heme·DNAzyme activity. In view of the strong catalytic activity of heme·DNAzyme in aqueous methanol, we were able to determine that a 60% v/v methanol-water mixture gives the most optimal yield of the dibenzothiophene sulfoxide (DBTO) oxidation product of petroleum-derived dibenzothiophene (DBT). The high product yield reflects both DNAzyme catalysis and a high substrate availability. Overall, these results emphasize the excellent promise of G-quadruplex forming DNA catalysts in application to "greener" industrial chemistry. This article is part of a Special Issue entitled "G-quadruplex" Guest Editor: Dr. Concetta Giancola and Dr. Daniela Montesarchio. Copyright © 2016 Elsevier B.V. All rights reserved.

Dynamical coupled-channels study of {pi}N{yields}{pi}{pi}N reactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kamano, H.; Julia-Diaz, B.; Department d'Estructura i Constituents de la Materia and Institut de Ciencies del Cosmos, Universitat de Barcelona E-08028 Barcelona

As a step toward performing a complete coupled-channels analysis of the world data of {pi}N,{gamma}*N{yields}{pi}N,{eta}N,{pi}{pi}N reactions, the {pi}N{yields}{pi}{pi}N reactions are investigated starting with the dynamical coupled-channels model developed in Phys. Rev. C 76, 065201 (2007). The channels included are {pi}N,{eta}N, and {pi}{pi}N which has {pi}{delta},{rho}N, and {sigma}N resonant components. The nonresonant amplitudes are generated from solving a set of coupled-channels equations with the meson-baryon potentials defined by effective Lagrangians. The resonant amplitudes are generated from 16 bare excited nucleon (N*) states that are dressed by the nonresonant interactions as constrained by the unitarity condition. The data of total cross sectionsmore » and {pi}N and {pi}{pi} invariant mass distributions of {pi}{sup +}p{yields}{pi}{sup +}{pi}{sup +}n,{pi}{sup +}{pi}{sup 0}p and {pi}{sup -}p{yields}{pi}{sup +}{pi}{sup -}n,{pi}{sup -}{pi}{sup 0}p,{pi}{sup 0}{pi}{sup 0}n reactions from threshold to the invariant mass W=2 GeV can be described to a very large extent. We show the importance of the coupled-channels effects and the strong interference among the contributions from the {pi}{delta},{sigma}N, and {rho}N channels. The large interference between the resonant and nonresonant amplitudes is also demonstrated. Possible future developments are discussed.« less

Strong polymer-turbulence interactions in viscoelastic turbulent channel flow.

PubMed

Dallas, V; Vassilicos, J C; Hewitt, G F

2010-12-01

This paper is focused on the fundamental mechanism(s) of viscoelastic turbulence that leads to polymer-induced turbulent drag reduction phenomenon. A great challenge in this problem is the computation of viscoelastic turbulent flows, since the understanding of polymer physics is restricted to mechanical models. An effective state-of-the-art numerical method to solve the governing equation for polymers modeled as nonlinear springs, without using any artificial assumptions as usual, was implemented here on a three-dimensional channel flow geometry. The capability of this algorithm to capture the strong polymer-turbulence dynamical interactions is depicted on the results, which are much closer qualitatively to experimental observations. This allowed a more detailed study of the polymer-turbulence interactions, which yields an enhanced picture on a mechanism resulting from the polymer-turbulence energy transfers.

77 FR 16131 - Establishing a White House Council on Strong Cities, Strong Communities

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-20

... Order 13602 of March 15, 2012 Establishing a White House Council on Strong Cities, Strong Communities By... inclusive, it is hereby ordered as follows: Section 1. Policy. Cities, towns, and regions across our Nation... collaboration, my Administration established the Strong Cities, Strong Communities (SC2) pilot initiative. By...

Annual Crop-Yield Variation, Child Survival, and Nutrition Among Subsistence Farmers in Burkina Faso.

PubMed

Belesova, Kristine; Gasparrini, Antonio; Sié, Ali; Sauerborn, Rainer; Wilkinson, Paul

2018-02-01

Whether year-to-year variation in crop yields affects the nutrition, health, and survival of subsistence-farming populations is relevant to the understanding of the potential impacts of climate change. However, the empirical evidence is limited. We examined the associations of child survival with interannual variation in food crop yield and middle-upper arm circumference (MUAC) in a subsistence-farming population of rural Burkina Faso. The study was of 44,616 children aged <5 years included in the Nouna Health and Demographic Surveillance System, 1992-2012, whose survival was analyzed in relation to the food crop yield in the year of birth (which ranged from 65% to 120% of the period average) and, for a subset of 16,698 children, to MUAC, using shared-frailty Cox proportional hazards models. Survival was appreciably worse in children born in years with low yield (full-adjustment hazard ratio = 1.11 (95% confidence interval: 1.02, 1.20) for a 90th- to 10th-centile decrease in annual crop yield) and in children with small MUAC (hazard ratio = 2.72 (95% confidence interval: 2.15, 3.44) for a 90th- to 10th-centile decrease in MUAC). These results suggest an adverse impact of variations in crop yields, which could increase under climate change. © The Author(s) 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Climatic and technological ceilings for Chinese rice stagnation based on yield gaps and yield trend pattern analysis.

PubMed

Zhang, Tianyi; Yang, Xiaoguang; Wang, Hesong; Li, Yong; Ye, Qing

2014-04-01

Climatic or technological ceilings could cause yield stagnation. Thus, identifying the principal reasons for yield stagnation within the context of the local climate and socio-economic conditions are essential for informing regional agricultural policies. In this study, we identified the climatic and technological ceilings for seven rice-production regions in China based on yield gaps and on a yield trend pattern analysis for the period 1980-2010. The results indicate that 54.9% of the counties sampled experienced yield stagnation since the 1980. The potential yield ceilings in northern and eastern China decreased to a greater extent than in other regions due to the accompanying climate effects of increases in temperature and decreases in radiation. This may be associated with yield stagnation and halt occurring in approximately 49.8-57.0% of the sampled counties in these areas. South-western China exhibited a promising scope for yield improvement, showing the greatest yield gap (30.6%), whereas the yields were stagnant in 58.4% of the sampled counties. This finding suggests that efforts to overcome the technological ceiling must be given priority so that the available exploitable yield gap can be achieved. North-eastern China, however, represents a noteworthy exception. In the north-central area of this region, climate change has increased the yield potential ceiling, and this increase has been accompanied by the most rapid increase in actual yield: 1.02 ton ha(-1) per decade. Therefore, north-eastern China shows a great potential for rice production, which is favoured by the current climate conditions and available technology level. Additional environmentally friendly economic incentives might be considered in this region. © 2013 John Wiley & Sons Ltd.

Factors governing the total rainfall yield from continental convective clouds

NASA Technical Reports Server (NTRS)

Rosenfeld, Daniel; Gagin, Abraham

1989-01-01

Several important factors that govern the total rainfall from continental convective clouds were investigated by tracking thousands of convective cells in Israel and South Africa. The rainfall volume yield (Rvol) of the individual cells that build convective rain systems has been shown to depend mainly on the cloud-top height. There is, however, considerable variability in this relationship. The following factors that influence the Rvol were parameterized and quantitatively analyzed: (1) cloud base temperature, (2)atmospheric instability, and (3) the extent of isolation of the cell. It is also shown that a strong low level forcing increases the duration of Rvol of clouds reaching the same vertical extent.

The strong UV source in the active E Galaxy NGC 4552

NASA Technical Reports Server (NTRS)

Oconnell, R. W.; Thuan, T. X.; Puschell, J. J.

1986-01-01

1200-3200 A IUE spectra of the nucleus of NGC 4552 (M89) were obtained in order to investigate the nature of the strong 10 micron source in this Galaxy. There is a strong, extended UV source in NGC 4552 which has a spatial distribution nearly identical with that at optical wavelengths and is undoubedly stellar in origin. Its properties are consistent with the correlation between UV source strength and metallicity pointed out by Faber (1983). There is no evidence for a nonthermal point source in the UV. It appears unlikely that the 10 micron emission is from heated dust grains. Instead, it is believed the 10 micron radiation is nonthermal in origin, implying a remarkably small size of only 0.1 AU for this source.

[Fluorescence spectra and quantum yield of TiO2 nanocrystals synthesized by alcohothermal method].

PubMed

Song, Cui-Hong; Li, Yan-Ting; Li, Jing; Wei, Yong-Ju; Hu, Yu-Zhu; Wei, Yu

2008-01-01

Fluorescence spectra and fluorescence quantum yield of TiO2 nanocrystals were studied. Using tetra n-butyl titanate as a starting material, a facile alcohothermal technique was used to synthesize TiO2 nanocrystals. As can be seen from the transmittance electron microscopy (TEM) image, TiO2 nanocrystals with a relatively uniform particle size distribution of < 10 nm are present in the transparent sol. The transparent sol presents a strong stable fluorescence emission with a maximum at 450 nm, which is greatly dependent on the size quantization effects, defect energy level and the surface state of TiO2 nanocrystals. The quantum yield (gamma) of TiO2 was determined by the relative comparison procedure, using freshly prepared analytical purity quinine sulfate in 0.05 mol x L(-1) H2SO4 as a relative quantum yield standard. The emission quantum yield of TiO2 nanocrystals prepared in alcoholic media was calculated to be about 0.20 at wavelengths ranging from 330 to 370 nm, which was much higher than the values reported in previous works. So, it is supposed that nano-TiO2 will be applied as a potential quantum dots fluorescence probe in biological analysis.

Control of the external photoluminescent quantum yield of emitters coupled to nanoantenna phased arrays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guo, Ke; Verschuuren, Marc A.; Lozano, Gabriel

2015-08-21

Optical losses in metals represent the largest limitation to the external quantum yield of emitters coupled to plasmonic antennas. These losses can be at the emission wavelength, but they can be more important at shorter wavelengths, i.e., at the excitation wavelength of the emitters, where the conductivity of metals is usually lower. We present accurate measurements of the absolute external photoluminescent quantum yield of a thin layer of emitting material deposited over a periodic nanoantenna phased array. Emission and absorptance measurements of the sample are performed using a custom-made setup including an integrating sphere and variable angle excitation. The measurementsmore » reveal a strong dependence of the external quantum yield on the angle at which the optical field excites the sample. Such behavior is attributed to the coupling between far-field illumination and near-field excitation mediated by the collective resonances supported by the array. Numerical simulations confirm that the inherent losses associated with the metal can be greatly reduced by selecting an optimum angle of illumination, which boosts the light conversion efficiency in the emitting layer. This combined experimental and numerical characterization of the emission from plasmonic arrays reveals the need to carefully design the illumination to achieve the maximum external quantum yield.« less

Strong-coupling of WSe2 in ultra-compact plasmonic nanocavities at room temperature.

PubMed

Kleemann, Marie-Elena; Chikkaraddy, Rohit; Alexeev, Evgeny M; Kos, Dean; Carnegie, Cloudy; Deacon, Will; de Pury, Alex Casalis; Große, Christoph; de Nijs, Bart; Mertens, Jan; Tartakovskii, Alexander I; Baumberg, Jeremy J

2017-11-03

Strong coupling of monolayer metal dichalcogenide semiconductors with light offers encouraging prospects for realistic exciton devices at room temperature. However, the nature of this coupling depends extremely sensitively on the optical confinement and the orientation of electronic dipoles and fields. Here, we show how plasmon strong coupling can be achieved in compact, robust, and easily assembled gold nano-gap resonators at room temperature. We prove that strong-coupling is impossible with monolayers due to the large exciton coherence size, but resolve clear anti-crossings for greater than 7 layer devices with Rabi splittings exceeding 135 meV. We show that such structures improve on prospects for nonlinear exciton functionalities by at least 10 4 , while retaining quantum efficiencies above 50%, and demonstrate evidence for superlinear light emission.

Strong size-dependent stress relaxation in electrospun polymer nanofibers

NASA Astrophysics Data System (ADS)

Wingert, Matthew C.; Jiang, Zhang; Chen, Renkun; Cai, Shengqiang

2017-01-01

Electrospun polymer nanofibers have garnered significant interest due to their strong size-dependent material properties, such as tensile moduli, strength, toughness, and glass transition temperatures. These properties are closely correlated with polymer chain dynamics. In most applications, polymers usually exhibit viscoelastic behaviors such as stress relaxation and creep, which are also determined by the motion of polymer chains. However, the size-dependent viscoelasticity has not been studied previously in polymer nanofibers. Here, we report the first experimental evidence of significant size-dependent stress relaxation in electrospun Nylon-11 nanofibers as well as size-dependent viscosity of the confined amorphous regions. In conjunction with the dramatically increasing stiffness of nano-scaled fibers, this strong relaxation enables size-tunable properties which break the traditional damping-stiffness tradeoff, qualifying electrospun nanofibers as a promising set of size-tunable materials with an unusual and highly desirable combination of simultaneously high stiffness and large mechanical energy dissipation.

Strong size-dependent stress relaxation in electrospun polymer nanofibers

DOE PAGES

Wingert, Matthew C.; Jiang, Zhang; Chen, Renkun; ...

2017-01-04

Here, electrospun polymer nanofibers have garnered significant interest due to their strong size-dependent material properties, such as tensile moduli, strength, toughness, and glass transition temperatures. These properties are closely correlated with polymer chain dynamics. In most applications, polymers usually exhibit viscoelastic behaviors such as stress relaxation and creep, which are also determined by the motion of polymer chains. However, the size-dependent viscoelasticity has not been studied previously in polymer nanofibers. Here, we report the first experimental evidence of significant size-dependent stress relaxation in electrospun Nylon-11 nanofibers as well as size-dependent viscosity of the confined amorphous regions. In conjunction with themore » dramatically increasing stiffness of nano-scaled fibers, this strong relaxation enables size-tunable properties which break the traditional damping-stiffness tradeoff, qualifying electrospun nanofibers as a promising set of size-tunable materials with an unusual and highly desirable combination of simultaneously high stiffness and large mechanical energy dissipation.« less

Impact of derived global weather data on simulated crop yields

PubMed Central

van Wart, Justin; Grassini, Patricio; Cassman, Kenneth G

2013-01-01

Crop simulation models can be used to estimate impact of current and future climates on crop yields and food security, but require long-term historical daily weather data to obtain robust simulations. In many regions where crops are grown, daily weather data are not available. Alternatively, gridded weather databases (GWD) with complete terrestrial coverage are available, typically derived from: (i) global circulation computer models; (ii) interpolated weather station data; or (iii) remotely sensed surface data from satellites. The present study's objective is to evaluate capacity of GWDs to simulate crop yield potential (Yp) or water-limited yield potential (Yw), which can serve as benchmarks to assess impact of climate change scenarios on crop productivity and land use change. Three GWDs (CRU, NCEP/DOE, and NASA POWER data) were evaluated for their ability to simulate Yp and Yw of rice in China, USA maize, and wheat in Germany. Simulations of Yp and Yw based on recorded daily data from well-maintained weather stations were taken as the control weather data (CWD). Agreement between simulations of Yp or Yw based on CWD and those based on GWD was poor with the latter having strong bias and large root mean square errors (RMSEs) that were 26–72% of absolute mean yield across locations and years. In contrast, simulated Yp or Yw using observed daily weather data from stations in the NOAA database combined with solar radiation from the NASA-POWER database were in much better agreement with Yp and Yw simulated with CWD (i.e. little bias and an RMSE of 12–19% of the absolute mean). We conclude that results from studies that rely on GWD to simulate agricultural productivity in current and future climates are highly uncertain. An alternative approach would impose a climate scenario on location-specific observed daily weather databases combined with an appropriate upscaling method. PMID:23801639

Subcycle dynamics of Coulomb asymmetry in strong elliptical laser fields.

PubMed

Li, Min; Liu, Yunquan; Liu, Hong; Ning, Qicheng; Fu, Libin; Liu, Jie; Deng, Yongkai; Wu, Chengyin; Peng, Liang-You; Peng, Liangyou; Gong, Qihuang

2013-07-12

We measure photoelectron angular distributions of noble gases in intense elliptically polarized laser fields, which indicate strong structure-dependent Coulomb asymmetry. Using a dedicated semiclassical model, we have disentangled the contribution of direct ionization and multiple forward scattering on Coulomb asymmetry in elliptical laser fields. Our theory quantifies the roles of the ionic potential and initial transverse momentum on Coulomb asymmetry, proving that the small lobes of asymmetry are induced by direct ionization and the strong asymmetry is induced by multiple forward scattering in the ionic potential. Both processes are distorted by the Coulomb force acting on the electrons after tunneling. Lowering the ionization potential, the relative contribution of direct ionization on Coulomb asymmetry substantially decreases and Coulomb focusing on multiple rescattering is more important. We do not observe evident initial longitudinal momentum spread at the tunnel exit according to our simulation.

Parameterizing the Supernova Engine and Its Effect on Remnants and Basic Yields

NASA Astrophysics Data System (ADS)

Fryer, Chris L.; Andrews, Sydney; Even, Wesley; Heger, Alex; Safi-Harb, Samar

2018-03-01

Core-collapse supernova science is now entering an era in which engine models are beginning to make both qualitative and, in some cases, quantitative predictions. Although the evidence in support of the convective engine for core-collapse supernova continues to grow, it is difficult to place quantitative constraints on this engine. Some studies have made specific predictions for the remnant distribution from the convective engine, but the results differ between different groups. Here we use a broad parameterization for the supernova engine to understand the differences between distinct studies. With this broader set of models, we place error bars on the remnant mass and basic yields from the uncertainties in the explosive engine. We find that, even with only three progenitors and a narrow range of explosion energies, we can produce a wide range of remnant masses and nucleosynthetic yields.

Reed canarygrass yield improvement

USDA-ARS?s Scientific Manuscript database

Reed canarygrass is well adapted to the northern USA. Eight cultivars and 72 accessions collected in rural landscapes from Iowa to New Hampshire were evaluated for yield. Accessions produced on average 7% higher biomass yield compared to existing cultivars. Naturalized populations of reed canarygras...

Generation of TiII Alkyne Trimerization Catalysts in the Absence of Strong Metal Reductants

PubMed Central

See, Xin Yi; Beaumier, Evan P.; Davis-Gilbert, Zachary W.; Dunn, Peter L.; Larsen, Jacob A.; Pearce, Adam J.; Wheeler, T. Alex; Tonks, Ian A.

2017-01-01

Low-valent TiII species have typically been synthesized by the reaction of TiIV halides with strong metal reductants. Herein we report that TiII species can be generated simply by reacting TiIV imido complexes with 2 equiv of alkyne, yielding a metallacycle that can reductively eliminate pyrrole while liberating TiII. In order to probe the generality of this process, TiII-catalyzed alkyne trimerization reactions were carried out with a diverse range of TiIV precatalysts. PMID:28690352

Postabortion Care: 20 Years of Strong Evidence on Emergency Treatment, Family Planning, and Other Programming Components

PubMed Central

Huber, Douglas; Curtis, Carolyn; Irani, Laili; Pappa, Sara; Arrington, Lauren

2016-01-01

ABSTRACT Worldwide 75 million women need postabortion care (PAC) services each year following safe or unsafe induced abortions and miscarriages. We reviewed more than 550 studies on PAC published between 1994 and 2013 in the peer-reviewed and gray literature, covering emergency treatment, postabortion family planning, organization of services, and related topics that impact practices and health outcomes, particularly in the Global South. In this article, we present findings from studies with strong evidence that have major implications for programs and practice. For example, vacuum aspiration reduced morbidity, costs, and time in comparison to sharp curettage. Misoprostol 400 mcg sublingually or 600 mcg orally achieved 89% to 99% complete evacuation rates within 2 weeks in multiple studies and was comparable in effectiveness, safety, and acceptability to manual vacuum aspiration. Misoprostol was safely introduced in several PAC programs through mid-level providers, extending services to secondary hospitals and primary health centers. In multiple studies, postabortion family planning uptake before discharge increased by 30–70 percentage points within 1–3 years of strengthening postabortion family planning services; in some cases, increases up to 60 percentage points in 4 months were achieved. Immediate postabortion contraceptive acceptance increased on average from 32% before the interventions to 69% post-intervention. Several studies found that women receiving immediate postabortion intrauterine devices and implants had fewer unintended pregnancies and repeat abortions than those who were offered delayed insertions. Postabortion family planning is endorsed by the professional organizations of obstetricians/gynecologists, midwives, and nurses as a standard of practice; major donors agree, and governments should be encouraged to provide universal access to postabortion family planning. Important program recommendations include offering all postabortion women

Strong-field and attosecond physics in solids

DOE PAGES

Ghimire, Shambhu; Ndabashimiye, Georges; DiChiara, Anthony D.; ...

2014-10-08

We review the status of strong-field and attosecond processes in bulk transparent solids near the Keldysh tunneling limit. For high enough fields and low-frequency excitations, the optical and electronic properties of dielectrics can be transiently and reversibly modified within the applied pulse. In Ghimire et al (2011 Phys. Rev. Lett. 107 167407) non-parabolic band effects were seen in photon-assisted tunneling experiments in ZnO crystals in a strong mid-infrared field. Using the same ZnO crystals, Ghimire et al (2011 Nat. Phys. 7 138–41) reported the first observation of non-pertubative high harmonics, extending well above the bandgap into the vacuum ultraviolet. Recent experiments by Schubert et al (2014 Nat. Photonics 8 119–23) showed a carrier envelope phase dependence in the harmonic spectrum in strong-field 30 THz driven GaSe crystals which is the most direct evidence yet of the role of sub-cycle electron dynamics in solid-state harmonic generation. The harmonic generation mechanism is different from the gas phase owing to the high density and periodicity of the crystal. For example, this results in a linear dependence of the high-energy cutoff with the applied field in contrast to the quadratic dependence in the gas phase. Sub-100 attosecond pulses could become possible if the harmonic spectrum can be extended into the extreme ultraviolet (XUV). Here we report harmonics generated in bulk MgO crystals, extending tomore » $$\\sim 26$$ eV when driven by ~35 fs, 800 nm pulses focused to a ~1 VÅ$$^{-1}$$ peak field. The fundamental strong-field and attosecond response also leads to Wannier–Stark localization and reversible semimetallization as seen in the sub-optical cycle behavior of XUV absorption and photocurrent experiments on fused silica by Schiffrin et al (2013 Nature 493 70–4) and Schultze et al (2013 Nature 493 75–8). These studies are advancing our understanding of fundamental strong-field and attosecond physics in solids with potential

Stone Age hut in Israel yields world's oldest evidence of bedding.

PubMed

Nadel, Dani; Weiss, Ehud; Simchoni, Orit; Tsatskin, Alexander; Danin, Avinoam; Kislev, Mordechai

2004-04-27

The earliest archaeological remains of dwelling huts built by Homo sapiens were found in various European Upper Paleolithic open-air camps. Although floors of huts were found in a small number of cases, modern organization of the home space that includes defined resting areas and bedding remains was not discovered. We report here the earliest in situ bedding exposed on a brush hut floor. It has recently been found at the previously submerged, excellently preserved 23,000-year-old fisher-hunter-gatherers' camp of Ohalo II, situated in Israel on the shore of the Sea of Galilee. The grass bedding consists of bunches of partially charred Puccinellia confer convoluta stems and leaves, covered by a thin compact layer of clay. It is arranged in a repeated pattern, on the floor, around a central hearth. This study describes the bedding in its original context on a well preserved intentionally constructed floor. It also reconstructs on the basis of direct evidence (combined with ethnographic analogies) the Upper Paleolithic hut as a house with three major components: a hearth, specific working locales, and a comfortable sleeping area near the walls.

Stone Age hut in Israel yields world's oldest evidence of bedding

PubMed Central

Nadel, Dani; Weiss, Ehud; Simchoni, Orit; Tsatskin, Alexander; Danin, Avinoam; Kislev, Mordechai

2004-01-01

The earliest archaeological remains of dwelling huts built by Homo sapiens were found in various European Upper Paleolithic open-air camps. Although floors of huts were found in a small number of cases, modern organization of the home space that includes defined resting areas and bedding remains was not discovered. We report here the earliest in situ bedding exposed on a brush hut floor. It has recently been found at the previously submerged, excellently preserved 23,000-year-old fisher-hunter-gatherers' camp of Ohalo II, situated in Israel on the shore of the Sea of Galilee. The grass bedding consists of bunches of partially charred Puccinellia confer convoluta stems and leaves, covered by a thin compact layer of clay. It is arranged in a repeated pattern, on the floor, around a central hearth. This study describes the bedding in its original context on a well preserved intentionally constructed floor. It also reconstructs on the basis of direct evidence (combined with ethnographic analogies) the Upper Paleolithic hut as a house with three major components: a hearth, specific working locales, and a comfortable sleeping area near the walls. PMID:15090648

Food security: the challenge of increasing wheat yield and the importance of not compromising food safety

PubMed Central

Curtis, T; Halford, N G

2014-01-01

Current wheat yield and consumption is considered in the context of the historical development of wheat, from early domestication through to modern plant breeding, the Green Revolution and wheat’s place as one of the world’s most productive and important crops in the 21st Century. The need for further improvement in the yield potential of wheat in order to meet current and impending challenges is discussed, including rising consumption and the demand for grain for fuel as well as food. Research on the complex genetics underlying wheat yield is described, including the identification of quantitative trait loci and individual genes, and the prospects of biotechnology playing a role in wheat improvement in the future are discussed. The challenge of preparing wheat to meet the problems of drought, high temperature and increasing carbon dioxide concentration that are anticipated to come about as a result of climate change is also reviewed. Wheat yield must be increased while not compromising food safety, and the emerging problem of processing contaminants is reviewed, focussing in particular on acrylamide, a contaminant that forms from free asparagine and reducing sugars during high temperature cooking and processing. Wheat breeders are strongly encouraged to consider the contaminant issue when breeding for yield. PMID:25540461

Hydrodynamics in a Degenerate, Strongly Attractive Fermi Gas

NASA Technical Reports Server (NTRS)

Thomas, John E.; Kinast, Joseph; Hemmer, Staci; Turlapov, Andrey; O'Hara, Ken; Gehm, Mike; Granade, Stephen

2004-01-01

In summary, we use all-optical methods with evaporative cooling near a Feshbach resonance to produce a strongly interacting degenerate Fermi gas. We observe hydrodynamic behavior in the expansion dynamics. At low temperatures, collisions may not explain the expansion dynamics. We observe hydrodynamics in the trapped gas. Our observations include collisionally-damped excitation spectra at high temperature which were not discussed above. In addition, we observe weakly damped breathing modes at low temperature. The observed temperature dependence of the damping time and hydrodynamic frequency are not consistent with collisional dynamics nor with collisionless mean field interactions. These observations constitute the first evidence for superfluid hydrodynamics in a Fermi gas.

Specific energy yield comparison between crystalline silicon and amorphous silicon based PV modules

NASA Astrophysics Data System (ADS)

Ferenczi, Toby; Stern, Omar; Hartung, Marianne; Mueggenburg, Eike; Lynass, Mark; Bernal, Eva; Mayer, Oliver; Zettl, Marcus

2009-08-01

As emerging thin-film PV technologies continue to penetrate the market and the number of utility scale installations substantially increase, detailed understanding of the performance of the various PV technologies becomes more important. An accurate database for each technology is essential for precise project planning, energy yield prediction and project financing. However recent publications showed that it is very difficult to get accurate and reliable performance data of theses technologies. This paper evaluates previously reported claims the amorphous silicon based PV modules have a higher annual energy yield compared to crystalline silicon modules relative to their rated performance. In order to acquire a detailed understanding of this effect, outdoor module tests were performed at GE Global Research Center in Munich. In this study we examine closely two of the five reported factors that contribute to enhanced energy yield of amorphous silicon modules. We find evidence to support each of these factors and evaluate their relative significance. We discuss aspects for improvement in how PV modules are sold and identify areas for further study further study.

Geoarchaeological evidence of strong prehistoric earthquakes in the New Madrid (Missouri) seismic zone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saucier, R.T.

1991-04-01

Sand blows and fissures that cover >10,500 km{sup 2} in northeastern Arkansas and southeastern Missouri attest to the severity of the 1811-1812 earthquake series in the New Madrid seismic zone. However, except for one occurence near New Madrid, Missouri, the region has been devoid of any evidence of other major shocks for at least 1.3 ka prior to 1811 and possibly for >9 ka. Stratigraphic relations and radiocarbon dating at a recently excavated archaeological site near East Prairie, Missouri, have revealed liquifaction phenomena attributable to a shock dated to within about 100 yr prior to A.D. 539 and a probablemore » second one dated between about A.D. 539 and 991.« less

Research on Condition Assessment Method of Transmission Tower Under the Action of Strong Wind

NASA Astrophysics Data System (ADS)

Huang, Ren-mou; An, Li-qiang; Zhang, Rong-lun; Wu, Jiong; Liang, Ya-feng

2018-03-01

Transmission towers are often subjected to the external damage of severe weather like strong wind and so on, which may cause the collapse due to the yield and fracture of the tower material. Aiming this issue, an assessment method was proposed in this paper to assess the operation condition of transmission towers under strong wind. With a reasonable assess index system established firstly, then the internal force of the tower material was solved and its stability was determined through the mechanical analysis of the transmission tower finite element model. Meanwhile, the condition risk level of the tower was finally determined by considering the difference among the influences of other factors like corrosion and loose of members, slope on the transmission tower through the analytic hierarchy process. The assessment method was applied to assess the wind-induced collapse of towers in 110kV Bao Yi II line in Wenchang City, Hainan Province, of which the result proves the method can assess the condition of transmission tower under strong wind and of guiding significance for improving the windproof capability of transmission towers.

Variations in yield and gluten proteins in durum wheat varieties under late-season foliar versus soil application of nitrogen fertilizer in a northern Mediterranean environment.

PubMed

Visioli, Giovanna; Bonas, Urbana; Dal Cortivo, Cristian; Pasini, Gabriella; Marmiroli, Nelson; Mosca, Giuliano; Vamerali, Teofilo

2018-04-01

With the increasing demand for high-quality foodstuffs and concern for environmental sustainability, late-season nitrogen (N) foliar fertilization of common wheat is now an important and widespread practice. This study investigated the effects of late-season foliar versus soil N fertilization on yield and protein content of four varieties of durum wheat, Aureo, Ariosto, Biensur and Liberdur, in a three-year field trial in northern Italy. Variations in low-molecular-weight glutenins (LMW-GS), high-molecular-weight glutenins (HMW-GS) and gliadins were assessed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). It was found that N applied to the canopy did not improve protein rate compared with N application to the soil (general mean 138 mg g -1 ), but moderately increased productivity in the high-yielding varieties Liberdur and Biensur (three-year means 7.23 vs 7.13 and 7.53 vs 7.09 t ha -1 respectively). Technological quality was mainly related to variety choice, Aureo and Ariosto having higher protein rates and glutenin/gliadin ratios. Also found was a strong 'variety × N application method' interaction in the proportions of protein subunits within each class, particularly LMW-GS and gliadins. A promising result was the higher N uptake efficiency, although as apparent balance, combined with higher HMW/LMW-GS ratio in var. Biensur. Late-season foliar N fertilization allows N fertilizer saving, potentially providing environmental benefits in the rainy climate of the northern Mediterranean area, and also leads to variety-dependent up-regulation of essential LMW-GS and gliadins. Variety choice is a key factor in obtaining high technological quality, although it is currently associated with modest grain yield. This study provides evidence of high quality in the specific high-yielding variety Biensur, suggesting its potential as a mono-varietal semolina for pasta production. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

On Strong Anticipation

PubMed Central

Stepp, N.; Turvey, M. T.

2009-01-01

We examine Dubois's (2003) distinction between weak anticipation and strong anticipation. Anticipation is weak if it arises from a model of the system via internal simulations. Anticipation is strong if it arises from the system itself via lawful regularities embedded in the system's ordinary mode of functioning. The assumption of weak anticipation dominates cognitive science and neuroscience and in particular the study of perception and action. The assumption of strong anticipation, however, seems to be required by anticipation's ubiquity. It is, for example, characteristic of homeostatic processes at the level of the organism, organs, and cells. We develop the formal distinction between strong and weak anticipation by elaboration of anticipating synchronization, a phenomenon arising from time delays in appropriately coupled dynamical systems. The elaboration is conducted in respect to (a) strictly physical systems, (b) the defining features of circadian rhythms, often viewed as paradigmatic of biological behavior based in internal models, (c) Pavlovian learning, and (d) forward models in motor control. We identify the common thread of strongly anticipatory systems and argue for its significance in furthering understanding of notions such as “internal”, “model” and “prediction”. PMID:20191086

The Impact of Changing Snowmelt Timing on Non-Irrigated Crop Yield in Idaho

NASA Astrophysics Data System (ADS)

Murray, E. M.; Cobourn, K.; Flores, A. N.; Pierce, J. L.; Kunkel, M. L.

2013-12-01

The impacts of climate change on water resources have implications for both agricultural production and grower welfare. Many mountainous regions in the western U.S. rely on snowmelt as the dominant surface water source, and in Idaho, reconstructions of spring snowmelt timing have demonstrated a trend toward earlier, more variable snowmelt dates within the past 20 years. This earlier date and increased variability in snowmelt timing have serious implications for agriculture, but there is considerable uncertainty about how agricultural impacts vary by region, crop-type, and practices like irrigation vs. dryland farming. Establishing the relationship between snowmelt timing and agricultural yield is important for understanding how changes in large-scale climatic indices (like snowmelt date) may be associated with changes in agricultural yield. This is particularly important where local practitioner behavior is influenced by historically observed relationships between these climate indices and yield. In addition, a better understanding of the influence of changes in snowmelt on non-irrigated crop yield may be extrapolated to better understand how climate change may alter biomass production in non-managed ecosystems. To investigate the impact of snowmelt date on non-irrigated crop yield, we developed a multiple linear regression model to predict historical wheat and barley yield in several Idaho counties as a function of snowmelt date, climate variables (precipitation and growing degree-days), and spatial differences between counties. The relationship between snowmelt timing and non-irrigated crop yield at the county level is strong in many of the models, but differs in magnitude and direction for the two different crops. Results show interesting spatial patterns of variability in the correlation between snowmelt timing and crop yield. In four southern counties that border the Snake River Plain and one county bordering Oregon, non-irrigated wheat and/or barley yield are

Inflow, Outflow, Yields, and Stellar Population Mixing in Chemical Evolution Models

NASA Astrophysics Data System (ADS)

Andrews, Brett H.; Weinberg, David H.; Schönrich, Ralph; Johnson, Jennifer A.

2017-02-01

Chemical evolution models are powerful tools for interpreting stellar abundance surveys and understanding galaxy evolution. However, their predictions depend heavily on the treatment of inflow, outflow, star formation efficiency (SFE), the stellar initial mass function, the SN Ia delay time distribution, stellar yields, and stellar population mixing. Using flexCE, a flexible one-zone chemical evolution code, we investigate the effects of and trade-offs between parameters. Two critical parameters are SFE and the outflow mass-loading parameter, which shift the knee in [O/Fe]-[Fe/H] and the equilibrium abundances that the simulations asymptotically approach, respectively. One-zone models with simple star formation histories follow narrow tracks in [O/Fe]-[Fe/H] unlike the observed bimodality (separate high-α and low-α sequences) in this plane. A mix of one-zone models with inflow timescale and outflow mass-loading parameter variations, motivated by the inside-out galaxy formation scenario with radial mixing, reproduces the two sequences better than a one-zone model with two infall epochs. We present [X/Fe]-[Fe/H] tracks for 20 elements assuming three different supernova yield models and find some significant discrepancies with solar neighborhood observations, especially for elements with strongly metallicity-dependent yields. We apply principal component abundance analysis to the simulations and existing data to reveal the main correlations among abundances and quantify their contributions to variation in abundance space. For the stellar population mixing scenario, the abundances of α-elements and elements with metallicity-dependent yields dominate the first and second principal components, respectively, and collectively explain 99% of the variance in the model. flexCE is a python package available at https://github.com/bretthandrews/flexCE.

Water content and porosity effect on hydrogen radiolytic yields of geopolymers

NASA Astrophysics Data System (ADS)

Chupin, Frédéric; Dannoux-Papin, Adeline; Ngono Ravache, Yvette; d'Espinose de Lacaillerie, Jean-Baptiste

2017-10-01

The behavior of geopolymers under irradiation is a topic that has not been thoroughly investigated so far. However, if geopolymers are considered to be used as radioactive waste embedding matrices, their chemical and mechanical stability under ionizing radiation as well as low hydrogen production must be demonstrated. For that purpose, a particular focus is put on water radiolysis. Various formulations of geopolymers have been irradiated either with γ-rays (60Co source) or 95 MeV/amu 36Ar18+ ions beams and the hydrogen production has been quantified. This paper presents the results of radiolytic gas analysis in order to identify important structural parameters that influence confined water radiolysis. A correlation between geopolymers nature, water content on the one side, and the hydrogen radiolytic yield (G(H2)) on the other side, has been demonstrated. For both types of irradiations, a strong influence of the water content on the hydrogen radiolytic yield G(H2) is evidenced. The geopolymers porosity effect has been only highlighted under γ-rays irradiation.

Optimization of dilute sulfuric acid pretreatment to maximize combined sugar yield from sugarcane bagasse for ethanol production.

PubMed

Benjamin, Y; Cheng, H; Görgens, J F

2014-01-01

Increasing fermentable sugar yields per gram of biomass depends strongly on optimal selection of varieties and optimization of pretreatment conditions. In this study, dilute acid pretreatment of bagasse from six varieties of sugarcane was investigated in connection with enzymatic hydrolysis for maximum combined sugar yield (CSY). The CSY from the varieties were also compared with the results from industrial bagasse. The results revealed considerable differences in CSY between the varieties. Up to 22.7 % differences in CSY at the optimal conditions was observed. The combined sugar yield difference between the best performing variety and the industrial bagasse was 34.1 %. High ratio of carbohydrates to lignin and low ash content favored the release of sugar from the substrates. At mild pretreatment conditions, the differences in bioconversion efficiency between varieties were greater than at severe condition. This observation suggests that under less severe conditions the glucose recovery was largely determined by chemical composition of biomass. The results from this study support the possibility of increasing sugar yields or improving the conversion efficiency when pretreatment optimization is performed on varieties with improved properties.

Analysis of the trade-off between high crop yield and low yield instability at the global scale

NASA Astrophysics Data System (ADS)

Ben-Ari, Tamara; Makowski, David

2016-10-01

Yield dynamics of major crops species vary remarkably among continents. Worldwide distribution of cropland influences both the expected levels and the interannual variability of global yields. An expansion of cultivated land in the most productive areas could theoretically increase global production, but also increase global yield instability if the most productive regions are characterized by high interannual yield variability. In this letter, we use portfolio analysis to quantify the tradeoff between the expected values and the interannual variance of global yield. We compute optimal frontiers for four crop species i.e., maize, rice, soybean and wheat and show how the distribution of cropland among large world regions can be optimized to either increase expected global crop production or decrease its interannual variability. We also show that a preferential allocation of cropland in the most productive regions can increase global expected yield at the expense of yield stability. Theoretically, optimizing the distribution of a small fraction of total cultivated areas can help find a good compromise between low instability and high crop yields at the global scale.

Strong-field approximation for ionization of a diatomic molecule by a strong laser field. II. The role of electron rescattering off the molecular centers

NASA Astrophysics Data System (ADS)

Busuladžić, M.; Gazibegović-Busuladžić, A.; Milošević, D. B.; Becker, W.

2008-09-01

The strong-field approximation for ionization of diatomic molecules by a strong laser field [D. B. Milošević, Phys. Rev. A 74, 063404 (2006)] is generalized to include rescattering of the ionized electron wave packet off the molecular centers (the electron’s parent ion or the second atom). There are four rescattering contributions to the ionization rate, which are responsible for the high-energy plateau in the electron spectra and which interfere in a complicated manner. The spectra are even more complicated due to the different symmetry properties of the atomic orbitals of which a particular molecular orbital consists. Nevertheless, a comparatively simple condition emerges for the destructive interference of all these contributions, which yields a curve in the (Epf,θ) plane. Here θ is the electron emission angle and Epf is the electron kinetic energy. The resulting suppression of the rescattering plateau can be strong and affect a large area of the (Epf,θ) plane, depending on the orientation of the molecule. We illustrate this using the examples of the 3σg molecular orbital of N2 and the 1πg molecular orbital of O2 for various orientations of these molecules with respect to the laser polarization axis. For N2 , for perpendicular orientation and the equilibrium internuclear distance R0 , we find that the minima of the ionization rate form the curve Epfcos2θ=π2/(2R02) in the (Epf,θ) plane. For O2 the rescattering plateau is absent for perpendicular orientation.

The potential of neuroscience for health sciences education: towards convergence of evidence and resisting seductive allure.

PubMed

de Bruin, Anique B H

2016-12-01

Since emergence of the field 'Educational Neuroscience' (EN) in the late nineties of the previous century, a debate has emerged about the potential this field holds to influence teaching and learning in the classroom. By now, most agree that the original claims promising direct translations to teaching and learning were too strong. I argue here that research questions in (health professions) education require multi-methodological approaches, including neuroscience, while carefully weighing what (combination of) approaches are most suitable given a research question. Only through a multi-methodological approach will convergence of evidence emerge, which is so desperately needed for improving teaching and learning in the classroom. However, both researchers and teachers should become aware of the so-called 'seductive allure' of EN; that is, the demonstrable physical location and apparent objectivity of the measurements can be interpreted as yielding more powerful evidence and warranting stronger conclusions than, e.g., behavioral experiments, where in fact oftentimes the reverse is the case. I conclude that our tendency as researchers to commit ourselves to one methodological approach and to addressing educational research questions from a single methodological perspective is limiting progress in educational science and in translation to education.

Tungsten oxide thin film exposed to low energy D and He plasma: evidence for a thermal enhancement of the erosion yield

NASA Astrophysics Data System (ADS)

Hijazi, Hussein; Martin, C.; Roubin, P.; Addab, Y.; Cabie, C.; Pardanaud, C.; Bannister, M.; Meyer, F.

2017-10-01

Nanocrystalline tungsten oxide thin films (25 nm - 250 nm thickness) produced by thermal oxidation of a tungsten substrate were exposed to low energy D and He plasma. Low energy D plasma exposure (11 eV/D+) of these films have resulted in the formation of a tungsten bronze (DxWO3) clearly observed by Raman microscopy. D plasma bombardment (4 1021 m-2) has also induced a color change of the oxide layer which is similar to the well-known electro-chromic effect and has been named ``plasma-chromic effect''. To unravel physical and chemical origins of the modifications observed under exposure, similar tungsten oxide films were also exposed to low energy helium plasma (20 eV/He+) . Due to the low fluence (4 1021 m-2) and low ion energy (20 eV), at room temperature, He exposure has induced only very few morphological and structural modifications. On the contrary, at 673 K, significant erosion is observed, which gives evidence for an unexpected thermal enhancement of the erosion yield. We present here new results concerning He beam exposures at low fluence (4 1021 m-2) varying the He+ energy from 20 eV to 320 eV to measure the tungsten oxide sputtering threshold energy. Detailed analyses before/after exposure to describe the D and He interaction with the oxide layer, its erosion and structural modification at the atomic and micrometer scale will be presented.

Optimized adhesives for strong, lightweight, damage-resistant, nanocomposite materials: new insights from natural materials

NASA Astrophysics Data System (ADS)

Hansma, P. K.; Turner, P. J.; Ruoff, R. S.

2007-01-01

From our investigations of natural composite materials such as abalone shell and bone we have learned the following. (1) Nature is frugal with resources: it uses just a few per cent glue, by weight, to glue together composite materials. (2) Nature does not avoid voids. (3) Nature makes optimized glues with sacrificial bonds and hidden length. We discuss how optimized adhesives combined with high specific stiffness/strength structures such as carbon nanotubes or graphene sheets could yield remarkably strong, lightweight, and damage-resistant materials.

77 FR 53212 - Notice of Proposed Information Collection: Comment Request Strong Cities Strong Communities...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-31

... Information Collection: Comment Request Strong Cities Strong Communities National Resource Network AGENCY... National Resource Network. OMB Control Number, if applicable: 2528--Pending. Description of the need for... information related to the proposed Strong Cities Strong Communities National Resource Network. The U.S...

Intercomparison of Soil Moisture, Evaporative Stress, and Vegetation Indices for Estimating Corn and Soybean Yields Over the U.S.

NASA Technical Reports Server (NTRS)

Mladenova, Iliana E.; Bolten, John D.; Crow, Wade T.; Anderson, Martha C.; Hain, C. R.; Johnson, David M.; Mueller, Rick

2017-01-01

This paper presents an intercomparative study of 12 operationally produced large-scale datasets describing soil moisture, evapotranspiration (ET), and or vegetation characteristics within agricultural regions of the contiguous United States (CONUS). These datasets have been developed using a variety of techniques, including, hydrologic modeling, satellite-based retrievals, data assimilation, and survey in-field data collection. The objectives are to assess the relative utility of each dataset for monitoring crop yield variability, to quantitatively assess their capacity for predicting end-of-season corn and soybean yields, and to examine the evolution of the yield-index correlations during the growing season. This analysis is unique both with regards to the number and variety of examined yield predictor datasets and the detailed assessment of the water availability timing on the end-of-season crop production during the growing season. Correlation results indicate that over CONUS, at state-level soil moisture and ET indices can provide better information for forecasting corn and soybean yields than vegetation-based indices such as normalized difference vegetation index. The strength of correlation with corn and soybean yields strongly depends on the interannual variability in yield measured at a given location. In this case study, some of the remotely derived datasets examined provide skill comparable to that of in situ field survey-based data further demonstrating the utility of these remote sensing-based approaches for estimating crop yield.

Evidence for Solar-Cycle Forcing and Secular Variation in the Armagh Observatory Temperature Record

NASA Technical Reports Server (NTRS)

Wilson, Robert M.

1998-01-01

A prominent feature of previous long-term temperature studies has been the appearance of warming since the 1880s, this often being taken as evidence for anthropogenic-induced global warming. In this investigation, the long-term, annual, mean temperature record (1844-1992) of the Armagh Observatory (Armagh, North Ireland), a set of temperature data based on maximum and minimum thermometers that predates the 1880s and correlates well with northern hemispheric and global standards, is examined for evidence of systematic variation, in particular, as related to solar-cycle forcing and secular variation. Indeed, both appear to be embedded within the Armagh data. Removal of these effects, each contributing about 8% to the overall reduction in variance, yields residuals that are randomly distributed. Application of the 10-year moving average to the residuals, furthermore, strongly suggests that the behavior of the residuals is episodic, inferring that (for extended periods of time) temperatures at Armagh sometimes were warmer or cooler (than expected), while at other times they were stable. Comparison of cyclic averages of annual mean temperatures against the lengths of the associated Hale cycles (i.e., the length of two, sequentially numbered, even-odd sunspot cycle pairs) strongly suggests that the temperatures correlate inversely (r = -0.886 at less than 2% level of significance) against the length of the associated Hale cycle. Because sunspot cycle 22 ended in 1996, the present Hale cycle probably will be shorter than average, implying that temperatures at Armagh over this Hale cycle will be warmer (about 9.31 q 0.23 C at the 90% confidence level) than average (= 9.00 C).

Quantifying potential yield and water-limited yield of summer maize in the North China Plain

NASA Astrophysics Data System (ADS)

Jiang, Mingnuo; Liu, Chaoshun; Chen, Maosi

2017-09-01

The North China Plain is a major food producing region in China, and climate change could pose a threat to food production in the region. Based on China Meteorological Forcing Dataset, simulating the growth of summer maize in North China Plain from 1979 to 2015 with the regional implementation of crop growth model WOFOST. The results showed that the model can reflect the potential yield and water-limited yield of Summer Maize in North China Plain through the calibration and validation of WOFOST model. After the regional implementation of model, combined with the reanalysis data, the model can better reproduce the regional history of summer maize yield in the North China Plain. The yield gap in Southeastern Beijing, southern Tianjin, southern Hebei province, Northwestern Shandong province is significant, these means the water condition is the main factor to summer maize yield in these regions.

Recent trends in vegetation greenness in China significantly altered annual evapotranspiration and water yield

NASA Astrophysics Data System (ADS)

Liu, Yibo; Xiao, Jingfeng; Ju, Weimin; Xu, Ke; Zhou, Yanlian; Zhao, Yuntai

2016-09-01

There has been growing evidence that vegetation greenness has been increasing in many parts of the northern middle and high latitudes including China during the last three to four decades. However, the effects of increasing vegetation greenness particularly afforestation on the hydrological cycle have been controversial. We used a process-based ecosystem model and a satellite-derived leaf area index (LAI) dataset to examine how the changes in vegetation greenness affected annual evapotranspiration (ET) and water yield for China over the period from 2000 to 2014. Significant trends in vegetation greenness were observed in 26.1% of China’s land area. We used two model simulations driven with original and detrended LAI, respectively, to assess the effects of vegetation ‘greening’ and ‘browning’ on terrestrial ET and water yield. On a per-pixel basis, vegetation greening increased annual ET and decreased water yield, while vegetation browning reduced ET and increased water yield. At the large river basin and national scales, the greening trends also had positive effects on annual ET and had negative effects on water yield. Our results showed that the effects of the changes in vegetation greenness on the hydrological cycle varied with spatial scale. Afforestation efforts perhaps should focus on southern China with larger water supply given the water crisis in northern China and the negative effects of vegetation greening on water yield. Future studies on the effects of the greenness changes on the hydrological cycle are needed to account for the feedbacks to the climate.

Outcomes of Stay Strong, Stay Healthy in community settings.

PubMed

Ball, Stephen; Gammon, Robin; Kelly, Patricia J; Cheng, An-Lin; Chertoff, Keyna; Kaume, Lydia; Abreu, Eduardo L; Brotto, Marco

2013-12-01

Loss of muscle strength, flexibility, and balance are strong predictors of falls in the elderly. The goal of this research was to investigate the effectiveness of a 10-week, strength-based exercise program delivered by Extension professionals. Matched pair t tests were used to compare differences in five measures of fitness collected from 808 participants (mean age = 65.4 years) at the start and finish of the exercise program. Following programming, participants significantly improved strength, flexibility, and balance. Results indicate that an evidence-based program can be translated into a community Extension program that is able to improve the fitness level of seniors.

Endoscopic management of acute necrotizing pancreatitis: European Society of Gastrointestinal Endoscopy (ESGE) evidence-based multidisciplinary guidelines.

PubMed

Arvanitakis, Marianna; Dumonceau, Jean-Marc; Albert, Jörg; Badaoui, Abdenor; Bali, Maria Antonietta; Barthet, Marc; Besselink, Marc; Deviere, Jacques; Oliveira Ferreira, Alexandre; Gyökeres, Tibor; Hritz, Istvan; Hucl, Tomas; Milashka, Marianna; Papanikolaou, Ioannis S; Poley, Jan-Werner; Seewald, Stefan; Vanbiervliet, Geoffroy; van Lienden, Krijn; van Santvoort, Hjalmar; Voermans, Rogier; Delhaye, Myriam; van Hooft, Jeanin

2018-05-01

1:  ESGE suggests using contrast-enhanced computed tomography (CT) as the first-line imaging modality on admission when indicated and up to the 4th week from onset in the absence of contraindications. Magnetic resonance imaging (MRI) may be used instead of CT in patients with contraindications to contrast-enhanced CT, and after the 4th week from onset when invasive intervention is considered because the contents (liquid vs. solid) of pancreatic collections are better characterized by MRI and evaluation of pancreatic duct integrity is possible. Weak recommendation, low quality evidence. 2:  ESGE recommends against routine percutaneous fine needle aspiration (FNA) of (peri)pancreatic collections. Strong recommendation, moderate quality evidence. FNA should be performed only if there is suspicion of infection and clinical/imaging signs are unclear. Weak recommendation, low quality evidence. 3:  ESGE recommends initial goal-directed intravenous fluid therapy with Ringer's lactate (e. g. 5 - 10 mL/kg/h) at onset. Fluid requirements should be patient-tailored and reassessed at frequent intervals. Strong recommendation, moderate quality evidence. 4:  ESGE recommends against antibiotic or probiotic prophylaxis of infectious complications in acute necrotizing pancreatitis. Strong recommendation, high quality evidence. 5:  ESGE recommends invasive intervention for patients with acute necrotizing pancreatitis and clinically suspected or proven infected necrosis. Strong recommendation, low quality evidence.ESGE suggests that the first intervention for infected necrosis should be delayed for 4 weeks if tolerated by the patient. Weak recommendation, low quality evidence. 6:  ESGE recommends performing endoscopic or percutaneous drainage of (suspected) infected walled-off necrosis as the first interventional method, taking into account the location of the walled-off necrosis and local expertise. Strong recommendation, moderate quality evidence. 7: �

Fission yield measurements at IGISOL

NASA Astrophysics Data System (ADS)

Lantz, M.; Al-Adili, A.; Gorelov, D.; Jokinen, A.; Kolhinen, V. S.; Mattera, A.; Moore, I.; Penttilä, H.; Pomp, S.; Prokofiev, A. V.; Rakopoulos, V.; Rinta-Antila, S.; Simutkin, V.; Solders, A.

2016-06-01

The fission product yields are an important characteristic of the fission process. In fundamental physics, knowledge of the yield distributions is needed to better understand the fission process. For nuclear energy applications good knowledge of neutroninduced fission-product yields is important for the safe and efficient operation of nuclear power plants. With the Ion Guide Isotope Separator On-Line (IGISOL) technique, products of nuclear reactions are stopped in a buffer gas and then extracted and separated by mass. Thanks to the high resolving power of the JYFLTRAP Penning trap, at University of Jyväskylä, fission products can be isobarically separated, making it possible to measure relative independent fission yields. In some cases it is even possible to resolve isomeric states from the ground state, permitting measurements of isomeric yield ratios. So far the reactions U(p,f) and Th(p,f) have been studied using the IGISOL-JYFLTRAP facility. Recently, a neutron converter target has been developed utilizing the Be(p,xn) reaction. We here present the IGISOL-technique for fission yield measurements and some of the results from the measurements on proton induced fission. We also present the development of the neutron converter target, the characterization of the neutron field and the first tests with neutron-induced fission.

Restricted mating dispersal and strong breeding group structure in a mid-sized marsupial mammal (Petrogale penicillata).

PubMed

Hazlitt, S L; Sigg, D P; Eldridge, M D B; Goldizen, A W

2006-09-01

Ecological genetic studies have demonstrated that spatial patterns of mating dispersal, the dispersal of gametes through mating behaviour, can facilitate inbreeding avoidance and strongly influence the structure of populations, particularly in highly philopatric species. Elements of breeding group dynamics, such as strong structuring and sex-biased dispersal among groups, can also minimize inbreeding and positively influence levels of genetic diversity within populations. Rock-wallabies are highly philopatric mid-sized mammals whose strong dependence on rocky terrain has resulted in series of discreet, small colonies in the landscape. Populations show no signs of inbreeding and maintain high levels of genetic diversity despite strong patterns of limited gene flow within and among colonies. We used this species to investigate the importance of mating dispersal and breeding group structure to inbreeding avoidance within a 'small' population. We examined the spatial patterns of mating dispersal, the extent of kinship within breeding groups, and the degree of relatedness among brush-tailed rock-wallaby breeding pairs within a colony in southeast Queensland. Parentage data revealed remarkably restricted mating dispersal and strong breeding group structuring for a mid-sized mammal. Breeding groups showed significant levels of female kinship with evidence of male dispersal among groups. We found no evidence for inbreeding avoidance through mate choice; however, anecdotal data suggest the importance of life history traits to inbreeding avoidance between first-degree relatives. We suggest that the restricted pattern of mating dispersal and strong breeding group structuring facilitates inbreeding avoidance within colonies. These results provide insight into the population structure and maintenance of genetic diversity within colonies of the threatened brush-tailed rock-wallaby.

Yield model development project implementation plan

NASA Technical Reports Server (NTRS)

Ambroziak, R. A.

1982-01-01

Tasks remaining to be completed are summarized for the following major project elements: (1) evaluation of crop yield models; (2) crop yield model research and development; (3) data acquisition processing, and storage; (4) related yield research: defining spectral and/or remote sensing data requirements; developing input for driving and testing crop growth/yield models; real time testing of wheat plant process models) and (5) project management and support.

Experimental evidence that density dependence strongly influences plant invasions through fragmented landscapes.

PubMed

Williams, Jennifer L; Levine, Jonathan M

2018-04-01

Populations of range expanding species encounter patches of both favorable and unfavorable habitat as they spread across landscapes. Theory shows that increasing patchiness slows the spread of populations modeled with continuously varying population density when dispersal is not influence by the environment or individual behavior. However, as is found in uniformly favorable landscapes, spread remains driven by fecundity and dispersal from low density individuals at the invasion front. In contrast, when modeled populations are composed of discrete individuals, patchiness causes populations to build up to high density before dispersing past unsuitable habitat, introducing an important influence of density dependence on spread velocity. To test the hypothesized interaction between habitat patchiness and density dependence, we simultaneously manipulated these factors in a greenhouse system of annual plants spreading through replicated experimental landscapes. We found that increasing the size of gaps and amplifying the strength of density dependence both slowed spread velocity, but contrary to predictions, the effect of amplified density dependence was similar across all landscape types. Our results demonstrate that the discrete nature of individuals in spreading populations has a strong influence on how both landscape patchiness and density dependence influence spread through demographic and dispersal stochasticity. Both finiteness and landscape structure should be critical components to theoretical predictions of future spread for range expanding native species or invasive species colonizing new habitat. © 2018 by the Ecological Society of America.

A regionally-adapted implementation of conservation agriculture delivers rapid improvements to soil properties associated with crop yield stability.

PubMed

Williams, Alwyn; Jordan, Nicholas R; Smith, Richard G; Hunter, Mitchell C; Kammerer, Melanie; Kane, Daniel A; Koide, Roger T; Davis, Adam S

2018-05-31

Climate models predict increasing weather variability, with negative consequences for crop production. Conservation agriculture (CA) may enhance climate resilience by generating certain soil improvements. However, the rate at which these improvements accrue is unclear, and some evidence suggests CA can lower yields relative to conventional systems unless all three CA elements are implemented: reduced tillage, sustained soil cover, and crop rotational diversity. These cost-benefit issues are important considerations for potential adopters of CA. Given that CA can be implemented across a wide variety of regions and cropping systems, more detailed and mechanistic understanding is required on whether and how regionally-adapted CA can improve soil properties while minimizing potential negative crop yield impacts. Across four US states, we assessed short-term impacts of regionally-adapted CA systems on soil properties and explored linkages with maize and soybean yield stability. Structural equation modeling revealed increases in soil organic matter generated by cover cropping increased soil cation exchange capacity, which improved soybean yield stability. Cover cropping also enhanced maize minimum yield potential. Our results demonstrate individual CA elements can deliver rapid improvements in soil properties associated with crop yield stability, suggesting that regionally-adapted CA may play an important role in developing high-yielding, climate-resilient agricultural systems.

Optimizing cropland cover for stable food production in Sub-Saharan Africa using simulated yield and Modern Portfolio Theory

NASA Astrophysics Data System (ADS)

Bodin, P.; Olin, S.; Pugh, T. A. M.; Arneth, A.

2014-12-01

Food security can be defined as stable access to food of good nutritional quality. In Sub Saharan Africa access to food is strongly linked to local food production and the capacity to generate enough calories to sustain the local population. Therefore it is important in these regions to generate not only sufficiently high yields but also to reduce interannual variability in food production. Traditionally, climate impact simulation studies have focused on factors that underlie maximum productivity ignoring the variability in yield. By using Modern Portfolio Theory, a method stemming from economics, we here calculate optimum current and future crop selection that maintain current yield while minimizing variance, vs. maintaining variance while maximizing yield. Based on simulated yield using the LPJ-GUESS dynamic vegetation model, the results show that current cropland distribution for many crops is close to these optimum distributions. Even so, the optimizations displayed substantial potential to either increase food production and/or to decrease its variance regionally. Our approach can also be seen as a method to create future scenarios for the sown areas of crops in regions where local food production is important for food security.

Weather-based forecasts of California crop yields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lobell, D B; Cahill, K N; Field, C B

2005-09-26

Crop yield forecasts provide useful information to a range of users. Yields for several crops in California are currently forecast based on field surveys and farmer interviews, while for many crops official forecasts do not exist. As broad-scale crop yields are largely dependent on weather, measurements from existing meteorological stations have the potential to provide a reliable, timely, and cost-effective means to anticipate crop yields. We developed weather-based models of state-wide yields for 12 major California crops (wine grapes, lettuce, almonds, strawberries, table grapes, hay, oranges, cotton, tomatoes, walnuts, avocados, and pistachios), and tested their accuracy using cross-validation over themore » 1980-2003 period. Many crops were forecast with high accuracy, as judged by the percent of yield variation explained by the forecast, the number of yields with correctly predicted direction of yield change, or the number of yields with correctly predicted extreme yields. The most successfully modeled crop was almonds, with 81% of yield variance captured by the forecast. Predictions for most crops relied on weather measurements well before harvest time, allowing for lead times that were longer than existing procedures in many cases.« less

Optical investigation of the strong spin-orbit-coupled magnetic semimetal YbMnBi2

NASA Astrophysics Data System (ADS)

Chaudhuri, Dipanjan; Cheng, Bing; Yaresko, Alexander; Gibson, Quinn D.; Cava, R. J.; Armitage, N. P.

2017-08-01

Strong spin-orbit coupling (SOC) can result in ground states with nontrivial topological properties. The situation is even richer in magnetic systems where the magnetic ordering can potentially have strong influence over the electronic band structure. The class of A MnBi2 (A = Sr, Ca) compounds are important in this context as they are known to host massive Dirac fermions with strongly anisotropic dispersion, which is believed to be due to the interplay between strong SOC and magnetic degrees of freedom. We report the optical conductivity of YbMnBi2, a newly discovered member of this family and a proposed Weyl semimetal (WSM) candidate with broken time reversal symmetry. Together with density functional theory (DFT) band-structure calculations, we show that the complex conductivity can be interpreted as the sum of an intraband Drude response and interband transitions. We argue that the canting of the magnetic moments that has been proposed to be essential for the realization of the WSM in an otherwise antiferromagnetically ordered system is not necessary to explain the optical conductivity. We believe our data is explained qualitatively by the uncanted magnetic structure with a small offset of the chemical potential from strict stochiometry. We find no definitive evidence of a bulk Weyl nodes. Instead, we see signatures of a gapped Dirac dispersion, common in other members of A MnBi2 family or compounds with similar 2D network of Bi atoms. We speculate that the evidence for a WSM seen in ARPES arises through a surface magnetic phase. Such an assumption reconciles all known experimental data.

Flood-tolerant rice reduces yield variability and raises expected yield, differentially benefitting socially disadvantaged groups

PubMed Central

Dar, Manzoor H.; de Janvry, Alain; Emerick, Kyle; Raitzer, David; Sadoulet, Elisabeth

2013-01-01

Approximately 30% of the cultivated rice area in India is prone to crop damage from prolonged flooding. We use a randomized field experiment in 128 villages of Orissa India to show that Swarna-Sub1, a recently released submergence-tolerant rice variety, has significant positive impacts on rice yield when fields are submerged for 7 to 14 days with no yield penalty without flooding. We estimate that Swarna-Sub1 offers an approximate 45% increase in yields over the current popular variety when fields are submerged for 10 days. We show additionally that low-lying areas prone to flooding tend to be more heavily occupied by people belonging to lower caste social groups. Thus, a policy relevant implication of our findings is that flood-tolerant rice can deliver both efficiency gains, through reduced yield variability and higher expected yield, and equity gains in disproportionately benefiting the most marginal group of farmers. PMID:24263095

Recent Results from Lohengrin on Fission Yields and Related Decay Properties

NASA Astrophysics Data System (ADS)

Serot, O.; Amouroux, C.; Bidaud, A.; Capellan, N.; Chabod, S.; Ebran, A.; Faust, H.; Kessedjian, G.; Köester, U.; Letourneau, A.; Litaize, O.; Martin, F.; Materna, T.; Mathieu, L.; Panebianco, S.; Regis, J.-M.; Rudigier, M.; Sage, C.; Urban, W.

2014-05-01

The Lohengrin mass spectrometer is one of the 40 instruments built around the reactor of the Institute Laue-Langevin (France) which delivers a very intense thermal neutron flux. Usually, Lohengrin was combined with a high-resolution ionization chamber in order to obtain good nuclear charge discrimination within a mass line, yielding an accurate isotopic yield determination. Unfortunately, this experimental procedure can only be applied for fission products with a nuclear charge less than about 42, i.e. in the light fission fragment region. Since 2008, a large collaboration has started with the aim of studying various fission aspects, mainly in the heavy fragment region. For that, a new experimental setup which allows isotopic identification by γ-ray spectrometry has been developed and validated. This technique was applied on the 239Pu(nth,f) reaction where about 65 fission product yields were measured with an uncertainty that has been reduced on average by a factor of 2 compared with what was that previously available in nuclear data libraries. The same γ-ray spectrometric technique is currently being applied to the study of the 233U(nth,f) reaction. Our aim is to deduce charge and mass distributions of the fission products and to complete the experimental data that exist mainly for light fission fragments. The measurement of 41 mass yields from the 241Am(2nth,f) reaction has been also performed. In addition to these activities on fission yield measurements, various new nanosecond isomers were discovered. Their presence can be revealed from a strong deformed ionic charge distribution compared to a 'normal' Gaussian shape. Finally, a new neutron long-counter detector designed to have a detection efficiency independent of the detected neutron energy has been built. Combining this neutron device with a Germanium detector and a beta-ray detector array allowed us to measure the beta-delayed neutron emission probability Pn of some important fission products for reactor

Risks, Outcomes, and Evidence-based Interventions for Girls in the U.S. Juvenile Justice System

PubMed Central

Leve, Leslie D.; Chamberlain, Patricia; Kim, Hyoun K.

2015-01-01

The proportion of the juvenile justice population that is comprised of females is increasing, yet few evidence-based models have been evaluated and implemented with girls in the juvenile justice system. Although much is known about the risk and protective factors for girls who participate in serious delinquency, significant gaps in the research base hamper the development and implementation of theoretically based intervention approaches. In this review, we first summarize the extant empirical work about the predictors and sequelae of juvenile justice involvement for girls. Identified risk and protective factors that correspond to girls’ involvement in the juvenile justice system have been shown to largely parallel those of boys, although exposure rates and magnitudes of association sometimes differ by sex. Second, we summarize findings from empirically validated, evidence-based interventions for juvenile justice–involved youths that have been tested with girls. The interventions include Functional Family Therapy, Multisystemic Therapy, Multidimensional Family Therapy, and Treatment Foster Care Oregon (formerly known as Multidimensional Treatment Foster Care). We conclude that existing evidence-based practices appear to be effective for girls. However, few studies have been sufficiently designed to permit conclusions about whether sex-specific interventions would yield any better outcomes for girls than would interventions that already exist for both sexes and that have a strong base of evidence to support them. Third, we propose recommendations for feasible, cost-efficient next steps to advance the research and intervention agendas for this under-researched, under-served population of highly vulnerable youths. PMID:26119215

Multiple lines of evidence for the origin of domesticated chili pepper, Capsicum annuum, in Mexico

PubMed Central

Kraft, Kraig H.; Brown, Cecil H.; Nabhan, Gary P.; Luedeling, Eike; Luna Ruiz, José de Jesús; Coppens d’Eeckenbrugge, Geo; Hijmans, Robert J.; Gepts, Paul

2014-01-01

The study of crop origins has traditionally involved identifying geographic areas of high morphological diversity, sampling populations of wild progenitor species, and the archaeological retrieval of macroremains. Recent investigations have added identification of plant microremains (phytoliths, pollen, and starch grains), biochemical and molecular genetic approaches, and dating through 14C accelerator mass spectrometry. We investigate the origin of domesticated chili pepper, Capsicum annuum, by combining two approaches, species distribution modeling and paleobiolinguistics, with microsatellite genetic data and archaeobotanical data. The combination of these four lines of evidence yields consensus models indicating that domestication of C. annuum could have occurred in one or both of two areas of Mexico: northeastern Mexico and central-east Mexico. Genetic evidence shows more support for the more northern location, but jointly all four lines of evidence support central-east Mexico, where preceramic macroremains of chili pepper have been recovered in the Valley of Tehuacán. Located just to the east of this valley is the center of phylogenetic diversity of Proto-Otomanguean, a language spoken in mid-Holocene times and the oldest protolanguage for which a word for chili pepper reconstructs based on historical linguistics. For many crops, especially those that do not have a strong archaeobotanical record or phylogeographic pattern, it is difficult to precisely identify the time and place of their origin. Our results for chili pepper show that expressing all data in similar distance terms allows for combining contrasting lines of evidence and locating the region(s) where cultivation and domestication of a crop began. PMID:24753581

Multiple lines of evidence for the origin of domesticated chili pepper, Capsicum annuum, in Mexico.

PubMed

Kraft, Kraig H; Brown, Cecil H; Nabhan, Gary P; Luedeling, Eike; Luna Ruiz, José de Jesús; Coppens d'Eeckenbrugge, Geo; Hijmans, Robert J; Gepts, Paul

2014-04-29

The study of crop origins has traditionally involved identifying geographic areas of high morphological diversity, sampling populations of wild progenitor species, and the archaeological retrieval of macroremains. Recent investigations have added identification of plant microremains (phytoliths, pollen, and starch grains), biochemical and molecular genetic approaches, and dating through (14)C accelerator mass spectrometry. We investigate the origin of domesticated chili pepper, Capsicum annuum, by combining two approaches, species distribution modeling and paleobiolinguistics, with microsatellite genetic data and archaeobotanical data. The combination of these four lines of evidence yields consensus models indicating that domestication of C. annuum could have occurred in one or both of two areas of Mexico: northeastern Mexico and central-east Mexico. Genetic evidence shows more support for the more northern location, but jointly all four lines of evidence support central-east Mexico, where preceramic macroremains of chili pepper have been recovered in the Valley of Tehuacán. Located just to the east of this valley is the center of phylogenetic diversity of Proto-Otomanguean, a language spoken in mid-Holocene times and the oldest protolanguage for which a word for chili pepper reconstructs based on historical linguistics. For many crops, especially those that do not have a strong archaeobotanical record or phylogeographic pattern, it is difficult to precisely identify the time and place of their origin. Our results for chili pepper show that expressing all data in similar distance terms allows for combining contrasting lines of evidence and locating the region(s) where cultivation and domestication of a crop began.

Inclination Angles of Black Hole X-Ray Binaries Manifest Strong Gravity around Black Holes

NASA Technical Reports Server (NTRS)

Zhang, S. N.; Zhang, Xiao-Ling; Yao, Yangsen

2002-01-01

System inclination angles have been determined for about 15 X-ray binaries, in which stellar mass black holes are considered to exist. These inclination angles range between 25 degrees and 80 degrees, but peaked between 60-70 degrees. This peak is not explained in the frame work of Newtonian gravity. However, this peak is reproduced naturally if we model the observed X-ray radiations as being produced in the accretion disks very close to the black hole horizons, where the extremely strong general and special relativistic effects, caused by the extremely strong gravity near the black hole horizons, modify the local radiation significantly as the X-rays propagate to the remote observer. Therefore the peak of the inclination angle distribution provides evidence or strong gravity around stellar mass black holes.

Direct experimental evidence for photoinduced strong-coupling polarons in organolead halide perovskite nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, Kaibo; Qatar Univ., Doha; Abdellah, Mohamed

Echoing the roaring success of their bulk coun-terparts, nano-objects built from organolead halide perov-skites (OLHP) present bright prospects for surpassing the performances of their conventional organic and inorganic analogues in photodriven technologies. Unraveling the pho-toinduced charge dynamics is essential for optimizing OLHP optoelectronic functionalities. However, mapping the carri-er-lattice interactions remains challenging, owing to their manifestations on multiple length scales and time scales. By correlating ultrafast time-resolved optical and X-ray absorp-tion measurements, this work reveals the photoinduced formation of strong-coupling polarons in CH 3NH 3PbBr 3 nanoparticles. Such polarons originate from the self-trapping of electrons in the net Coulombic field causedmore » by the dis-placed inorganic nuclei and the oriented organic cations. The transient structural change detected at the Pb L 3 X-ray ab-sorption edge is well captured by a distortion with average bond elongation in the [PbBr 6] 2- motif. As a result, general implications for designing novel OLHP nanomaterials targeting the active utilization of these quasi-particles are outlined.« less

Direct experimental evidence for photoinduced strong-coupling polarons in organolead halide perovskite nanoparticles

DOE PAGES

Zheng, Kaibo; Qatar Univ., Doha; Abdellah, Mohamed; ...

2016-10-28

Echoing the roaring success of their bulk coun-terparts, nano-objects built from organolead halide perov-skites (OLHP) present bright prospects for surpassing the performances of their conventional organic and inorganic analogues in photodriven technologies. Unraveling the pho-toinduced charge dynamics is essential for optimizing OLHP optoelectronic functionalities. However, mapping the carri-er-lattice interactions remains challenging, owing to their manifestations on multiple length scales and time scales. By correlating ultrafast time-resolved optical and X-ray absorp-tion measurements, this work reveals the photoinduced formation of strong-coupling polarons in CH 3NH 3PbBr 3 nanoparticles. Such polarons originate from the self-trapping of electrons in the net Coulombic field causedmore » by the dis-placed inorganic nuclei and the oriented organic cations. The transient structural change detected at the Pb L 3 X-ray ab-sorption edge is well captured by a distortion with average bond elongation in the [PbBr 6] 2- motif. As a result, general implications for designing novel OLHP nanomaterials targeting the active utilization of these quasi-particles are outlined.« less

Sustainable management in crop monocultures: the impact of retaining forest on oil palm yield.

PubMed

Edwards, Felicity A; Edwards, David P; Sloan, Sean; Hamer, Keith C

2014-01-01

Tropical agriculture is expanding rapidly at the expense of forest, driving a global extinction crisis. How to create agricultural landscapes that minimise the clearance of forest and maximise sustainability is thus a key issue. One possibility is protecting natural forest within or adjacent to crop monocultures to harness important ecosystem services provided by biodiversity spill-over that may facilitate production. Yet this contrasts with the conflicting potential that the retention of forest exports dis-services, such as agricultural pests. We focus on oil palm and obtained yields from 499 plantation parcels spanning a total of ≈23,000 ha of oil palm plantation in Sabah, Malaysian Borneo. We investigate the relationship between the extent and proximity of both contiguous and fragmented dipterocarp forest cover and oil palm yield, controlling for variation in oil palm age and for environmental heterogeneity by incorporating proximity to non-native forestry plantations, other oil palm plantations, and large rivers, elevation and soil type in our models. The extent of forest cover and proximity to dipterocarp forest were not significant predictors of oil palm yield. Similarly, proximity to large rivers and other oil palm plantations, as well as soil type had no significant effect. Instead, lower elevation and closer proximity to forestry plantations had significant positive impacts on oil palm yield. These findings suggest that if dipterocarp forests are exporting ecosystem service benefits or ecosystem dis-services, that the net effect on yield is neutral. There is thus no evidence to support arguments that forest should be retained within or adjacent to oil palm monocultures for the provision of ecosystem services that benefit yield. We urge for more nuanced assessments of the impacts of forest and biodiversity on yields in crop monocultures to better understand their role in sustainable agriculture.

Sustainable Management in Crop Monocultures: The Impact of Retaining Forest on Oil Palm Yield

PubMed Central

Edwards, Felicity A.; Edwards, David P.; Sloan, Sean; Hamer, Keith C.

2014-01-01

Tropical agriculture is expanding rapidly at the expense of forest, driving a global extinction crisis. How to create agricultural landscapes that minimise the clearance of forest and maximise sustainability is thus a key issue. One possibility is protecting natural forest within or adjacent to crop monocultures to harness important ecosystem services provided by biodiversity spill-over that may facilitate production. Yet this contrasts with the conflicting potential that the retention of forest exports dis-services, such as agricultural pests. We focus on oil palm and obtained yields from 499 plantation parcels spanning a total of ≈23,000 ha of oil palm plantation in Sabah, Malaysian Borneo. We investigate the relationship between the extent and proximity of both contiguous and fragmented dipterocarp forest cover and oil palm yield, controlling for variation in oil palm age and for environmental heterogeneity by incorporating proximity to non-native forestry plantations, other oil palm plantations, and large rivers, elevation and soil type in our models. The extent of forest cover and proximity to dipterocarp forest were not significant predictors of oil palm yield. Similarly, proximity to large rivers and other oil palm plantations, as well as soil type had no significant effect. Instead, lower elevation and closer proximity to forestry plantations had significant positive impacts on oil palm yield. These findings suggest that if dipterocarp forests are exporting ecosystem service benefits or ecosystem dis-services, that the net effect on yield is neutral. There is thus no evidence to support arguments that forest should be retained within or adjacent to oil palm monocultures for the provision of ecosystem services that benefit yield. We urge for more nuanced assessments of the impacts of forest and biodiversity on yields in crop monocultures to better understand their role in sustainable agriculture. PMID:24638038

Nut crop yield records show that budbreak-based chilling requirements may not reflect yield decline chill thresholds

NASA Astrophysics Data System (ADS)

Pope, Katherine S.; Dose, Volker; Da Silva, David; Brown, Patrick H.; DeJong, Theodore M.

2015-06-01

Warming winters due to climate change may critically affect temperate tree species. Insufficiently cold winters are thought to result in fewer viable flower buds and the subsequent development of fewer fruits or nuts, decreasing the yield of an orchard or fecundity of a species. The best existing approximation for a threshold of sufficient cold accumulation, the "chilling requirement" of a species or variety, has been quantified by manipulating or modeling the conditions that result in dormant bud breaking. However, the physiological processes that affect budbreak are not the same as those that determine yield. This study sought to test whether budbreak-based chilling thresholds can reasonably approximate the thresholds that affect yield, particularly regarding the potential impacts of climate change on temperate tree crop yields. County-wide yield records for almond ( Prunus dulcis), pistachio ( Pistacia vera), and walnut ( Juglans regia) in the Central Valley of California were compared with 50 years of weather records. Bayesian nonparametric function estimation was used to model yield potentials at varying amounts of chill accumulation. In almonds, average yields occurred when chill accumulation was close to the budbreak-based chilling requirement. However, in the other two crops, pistachios and walnuts, the best previous estimate of the budbreak-based chilling requirements was 19-32 % higher than the chilling accumulations associated with average or above average yields. This research indicates that physiological processes beyond requirements for budbreak should be considered when estimating chill accumulation thresholds of yield decline and potential impacts of climate change.

Variability in soybean yield in Brazil stemming from the interaction of heterogeneous management and climate variability

NASA Astrophysics Data System (ADS)

Cohn, A.; Bragança, A.; Jeffries, G. R.

2017-12-01

An increasing share of global agricultural production can be found in the humid tropics. Therefore, an improved understanding of the mechanisms governing variability in the output of tropical agricultural systems is of increasing importance for food security including through climate change adaptation. Yet, the long window over which many tropical crops can be sown, the diversity of crop varieties and management practices combine to challenge inference into climate risk to cropping output in analyses of tropical crop-climate sensitivity employing administrative data. In this paper, we leverage a newly developed spatially explicit dataset of soybean yields in Brazil to combat this problem. The dataset was built by training a model of remotely-sensed vegetation index data and land cover classification data using a rich in situ dataset of soybean yield and management variables collected over the period 2006 to 2016. The dataset contains soybean yields by plant date, cropping frequency, and maturity group for each 5km grid cell in Brazil. We model variation in these yields using an approach enabling the estimation of the influence of management factors on the sensitivity of soybean yields to variability in: cumulative solar radiation, extreme degree days, growing degree days, flooding rain in the harvest period, and dry spells in the rainy season. We find strong variation in climate sensitivity by management class. Planting date and maturity group each explained a great deal more variation in yield sensitivity than did cropping frequency. Brazil collects comparatively fine spatial resolution yield data. But, our attempt to replicate our results using administrative soy yield data revealed substantially lesser crop-climate sensitivity; suggesting that previous analyses employing administrative data may have underestimated climate risk to tropical soy production.

A Case Study of Improving Yield Prediction and Sulfur Deficiency Detection Using Optical Sensors and Relationship of Historical Potato Yield with Weather Data in Maine

PubMed Central

Sharma, Lakesh K.; Bali, Sukhwinder K.; Dwyer, James D.; Plant, Andrew B.; Bhowmik, Arnab

2017-01-01

In Maine, potato yield is consistent, 38 t·ha−1, for last 10 years except 2016 (44 t·ha−1) which confirms that increasing the yield and quality of potatoes with current fertilization practices is difficult; hence, new or improvised agronomic methods are needed to meet with producers and industry requirements. Normalized difference vegetative index (NDVI) sensors have shown promise in regulating N as an in season application; however, using late N may stretch out the maturation stage. The purpose of the research was to test Trimble GreenSeeker® (TGS) and Holland Scientific Crop Circle™ ACS-430 (HCCACS-430) wavebands to predict potato yield, before the second hilling (6–8 leaf stage). Ammonium sulfate, S containing N fertilizer, is not advised to be applied on acidic soils but accounts for 60–70% fertilizer in Maine’s acidic soils; therefore, sensors are used on sulfur deficient site to produce sensor-bound S application guidelines before recommending non-S-bearing N sources. Two study sites investigated for this research include an S deficient site and a regular spot with two kinds of soils. Six N treatments, with both calcium ammonium nitrate and ammonium nitrate, under a randomized complete block design with four replications, were applied at planting. NDVI readings from both sensors were obtained at V8 leaf stages (8 leaf per plant) before the second hilling. Both sensors predict N and S deficiencies with a strong interaction with an average coefficient of correlation (r2) ~45. However, HCCACS-430 was observed to be more virtuous than TGS. The correlation between NDVI (from both sensors) and the potato yield improved using proprietor-proxy leaf area index (PPLAI) from HCCACS-430, e.g., r2 value of TGS at Easton site improve from 48 to 60. Weather data affected marketable potato yield (MPY) significantly from south to north in Maine, especially precipitation variations that could be employed in the N recommendations at planting and in season

Elasticity and yielding of a calcite paste: scaling laws in a dense colloidal suspension.

PubMed

Liberto, Teresa; Le Merrer, Marie; Barentin, Catherine; Bellotto, Maurizio; Colombani, Jean

2017-03-08

We address the mechanical characterization of a calcite paste as a model system to investigate the relation between the microstructure and macroscopic behavior of colloidal suspensions. The ultimate goal is to achieve control of the elastic and yielding properties of calcite which will prove valuable in several domains, from paper coating to paint manufacture and eventually in the comprehension and control of the mechanical properties of carbonate rocks. Rheological measurements have been performed on calcite suspensions over a wide range of particle concentrations. The calcite paste exhibits a typical colloidal gel behavior, with an elastic regime and a clear yield strain above which it enters a plastic regime. The yield strain shows a minimum when increasing the solid concentration, connected to a change in the power law scaling of the storage modulus. In the framework of the classical fractal elasticity model for colloidal suspensions proposed by Shih et al. [Phys. Rev. A, 1990, 42, 4772], we interpret this behavior as a switch with the concentration from the strong-link regime to the weak-link regime, which had never been observed so far in one well-defined system without external or chemical forcing.

Effect of nanoconfinement on the sputter yield in ultrathin polymeric films: Experiments and model

NASA Astrophysics Data System (ADS)

Cristaudo, Vanina; Poleunis, Claude; Delcorte, Arnaud

2018-06-01

This fundamental contribution on secondary ion mass spectrometry (SIMS) polymer depth-profiling by large argon clusters investigates the dependence of the sputter yield volume (Y) on the thickness (d) of ultrathin films as a function of the substrate nature, i.e. hard vs soft. For this purpose, thin films of polystyrene (PS) oligomers (∼4,000 amu) are spin-coated, respectively, onto silicon and poly (methyl methacrylate) supports and, then, bombarded by 10 keV Ar3000+ ions. The investigated thickness ranges from 15 to 230 nm. Additionally, the influence of the polymer molecular weight on Y(d) for PS thin films on Si is explored. The sputtering efficiency is found to be strongly dependent on the overlayer thickness, only in the case of the silicon substrate. A simple phenomenological model is proposed for the description of the thickness influence on the sputtering yield. Molecular dynamics (MD) simulations conducted on amorphous films of polyethylene-like oligomers of increasing thickness (from 2 to 20 nm), under comparable cluster bombardment conditions, predict a significant increase of the sputtering yield for ultrathin layers on hard substrates, induced by energy confinement in the polymer, and support our phenomenological model.

Evidence-based surgery: barriers, solutions, and the role of evidence synthesis.

PubMed

Garas, George; Ibrahim, Amel; Ashrafian, Hutan; Ahmed, Kamran; Patel, Vanash; Okabayashi, Koji; Skapinakis, Petros; Darzi, Ara; Athanasiou, Thanos

2012-08-01

Surgery is a rapidly evolving field, making the rigorous testing of emerging innovations vital. However, most surgical research fails to employ randomized controlled trials (RCTs) and has particularly been based on low-quality study designs. Subsequently, the analysis of data through meta-analysis and evidence synthesis is particularly difficult. Through a systematic review of the literature, this article explores the barriers to achieving a strong evidence base in surgery and offers potential solutions to overcome the barriers. Many barriers exist to evidence-based surgical research. They include enabling factors, such as funding, time, infrastructure, patient preference, ethical issues, and additionally barriers associated with specific attributes related to researchers, methodologies, or interventions. Novel evidence synthesis techniques in surgery are discussed, including graphics synthesis, treatment networks, and network meta-analyses that help overcome many of the limitations associated with existing techniques. They offer the opportunity to assess gaps and quantitatively present inconsistencies within the existing evidence of RCTs. Poorly or inadequately performed RCTs and meta-analyses can give rise to incorrect results and thus fail to inform clinical practice or revise policy. The above barriers can be overcome by providing academic leadership and good organizational support to ensure that adequate personnel, resources, and funding are allocated to the researcher. Training in research methodology and data interpretation can ensure that trials are conducted correctly and evidence is adequately synthesized and disseminated. The ultimate goal of overcoming the barriers to evidence-based surgery includes the improved quality of patient care in addition to enhanced patient outcomes.

Machine-smoking studies of cigarette filter color to estimate tar yield by visual assessment and through the use of a colorimeter.

PubMed

Morton, Michael J; Williams, David L; Hjorth, Heather B; Smith, Jennifer H

2010-04-01

This paper explores using the intensity of the stain on the end of the filter ("filter color") as a vehicle for estimating cigarette tar yield, both by instrument reading of the filter color and by visual comparison to a template. The correlation of machine-measured tar yield to filter color measured with a colorimeter was reasonably strong and was relatively unaffected by different puff volumes or different tobacco moistures. However, the correlation of filter color to machine-measured nicotine yield was affected by the moisture content of the cigarette. Filter color, as measured by a colorimeter, was generally comparable to filter extraction of either nicotine or solanesol in its correlation to machine-smoked tar yields. It was found that the color of the tar stain changes over time. Panelists could generally correctly order the filters from machine-smoked cigarettes by tar yield using the intensity of the tar stain. However, there was considerable variation in the panelist-to-panelist tar yield estimates. The wide person-to-person variation in tar yield estimates, and other factors discussed in the text could severely limit the usefulness and practicality of this approach for visually estimating the tar yield of machine-smoked cigarettes. Copyright 2009 Elsevier Inc. All rights reserved.

Strong spin-lattice coupling in CrSiTe 3

DOE PAGES

Casto, L. D.; Clune, A. J.; Yokosuk, M. O.; ...

2015-03-19

CrSiTe 3 has attracted recent interest as a candidate single-layer ferromagnetic semiconductor, but relatively little is known about the bulk properties of this material. Here, we report single-crystal X-ray diffraction, magnetic properties, thermal conductivity, vibrational, and optical spectroscopies and compare our findings with complementary electronic structure and lattice dynamics principles calculations. The high temperature paramagnetic phase is characterized by strong spin-lattice interactions that give rise to glassy behavior, negative thermal expansion, and an optical response that reveals that CrSiTe 3 is an indirect gap semiconductor with indirect and direct band gaps at 0.4 and 1.2 eV, respectively. Measurements of themore » phonons across the 33 K ferromagnetic transition provide additional evidence for strong coupling between the magnetic and lattice degrees of freedom. In conclusion, the Si-Te stretching and Te displacement modes are sensitive to the magnetic ordering transition, a finding that we discuss in terms of the superexchange mechanism. Lastly, spin-lattice coupling constants are also extracted.« less

Strong Navajo Marriages

ERIC Educational Resources Information Center

Skogrand, Linda; Mueller, Mary Lou; Arrington, Rachel; LeBlanc, Heidi; Spotted Elk, Davina; Dayzie, Irene; Rosenbrand, Reva

2008-01-01

The purpose of this qualitative study, conducted in two Navajo Nation chapters, was to learn what makes Navajo marriages strong because no research has been done on this topic. Twenty-one Navajo couples (42 individuals) who felt they had strong marriages volunteered to participate in the study. Couples identified the following marital strengths:…

Inflow, Outflow, Yields, and Stellar Population Mixing in Chemical Evolution Models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andrews, Brett H.; Weinberg, David H.; Schönrich, Ralph

Chemical evolution models are powerful tools for interpreting stellar abundance surveys and understanding galaxy evolution. However, their predictions depend heavily on the treatment of inflow, outflow, star formation efficiency (SFE), the stellar initial mass function, the SN Ia delay time distribution, stellar yields, and stellar population mixing. Using flexCE, a flexible one-zone chemical evolution code, we investigate the effects of and trade-offs between parameters. Two critical parameters are SFE and the outflow mass-loading parameter, which shift the knee in [O/Fe]–[Fe/H] and the equilibrium abundances that the simulations asymptotically approach, respectively. One-zone models with simple star formation histories follow narrow tracksmore » in [O/Fe]–[Fe/H] unlike the observed bimodality (separate high- α and low- α sequences) in this plane. A mix of one-zone models with inflow timescale and outflow mass-loading parameter variations, motivated by the inside-out galaxy formation scenario with radial mixing, reproduces the two sequences better than a one-zone model with two infall epochs. We present [X/Fe]–[Fe/H] tracks for 20 elements assuming three different supernova yield models and find some significant discrepancies with solar neighborhood observations, especially for elements with strongly metallicity-dependent yields. We apply principal component abundance analysis to the simulations and existing data to reveal the main correlations among abundances and quantify their contributions to variation in abundance space. For the stellar population mixing scenario, the abundances of α -elements and elements with metallicity-dependent yields dominate the first and second principal components, respectively, and collectively explain 99% of the variance in the model. flexCE is a python package available at https://github.com/bretthandrews/flexCE.« less

Herbicides do not ensure for higher wheat yield, but eliminate rare plant species

PubMed Central

Gaba, Sabrina; Gabriel, Edith; Chadœuf, Joël; Bonneu, Florent; Bretagnolle, Vincent

2016-01-01

Weed control is generally considered to be essential for crop production and herbicides have become the main method used for weed control in developed countries. However, concerns about harmful environmental consequences have led to strong pressure on farmers to reduce the use of herbicides. As food demand is forecast to increase by 50% over the next century, an in-depth quantitative analysis of crop yields, weeds and herbicides is required to balance economic and environmental issues. This study analysed the relationship between weeds, herbicides and winter wheat yields using data from 150 winter wheat fields in western France. A Bayesian hierarchical model was built to take account of farmers’ behaviour, including implicitly their perception of weeds and weed control practices, on the effectiveness of treatment. No relationship was detected between crop yields and herbicide use. Herbicides were found to be more effective at controlling rare plant species than abundant weed species. These results suggest that reducing the use of herbicides by up to 50% could maintain crop production, a result confirmed by previous studies, while encouraging weed biodiversity. Food security and biodiversity conservation may, therefore, be achieved simultaneously in intensive agriculture simply by reducing the use of herbicides. PMID:27453451

Enhanced electron yield from laser-driven wakefield acceleration in high-Z gas jets.

PubMed

Mirzaie, Mohammad; Hafz, Nasr A M; Li, Song; Liu, Feng; He, Fei; Cheng, Ya; Zhang, Jie

2015-10-01

An investigation of the electron beam yield (charge) form helium, nitrogen, and neon gas jet plasmas in a typical laser-plasma wakefield acceleration experiment is carried out. The charge measurement is made by imaging the electron beam intensity profile on a fluorescent screen into a charge coupled device which was cross-calibrated with an integrated current transformer. The dependence of electron beam charge on the laser and plasma conditions for the aforementioned gases are studied. We found that laser-driven wakefield acceleration in low Z-gas jet targets usually generates high-quality and well-collimated electron beams with modest yields at the level of 10-100 pC. On the other hand, filamentary electron beams which are observed from high-Z gases at higher densities reached much higher yields. Evidences for cluster formation were clearly observed in the nitrogen gas jet target, where we received the highest electron beam charge of ∼1.7 nC. Those intense electron beams will be beneficial for the applications on the generation of bright X-rays, gamma rays radiations, and energetic positrons via the bremsstrahlung or inverse-scattering processes.

New Evidence for Efficient Collisionless Heating of Electrons at the Reverse Shock of a Young Supernova Remnant

NASA Technical Reports Server (NTRS)

Yamaguchi, Hiroya; Eriksen, Kristoffer A.; Badenes, Carles; Hughes, John P.; Brickhouse, Nancy S.; Foster, Adam R.; Patnaude, Daniel J.; Petre, Robert; Slane, Patrick O.; Smith, Randall K.

2013-01-01

Although collisionless shocks are ubiquitous in astrophysics, certain key aspects of them are not well understood. In particular, the process known as collisionless electron heating, whereby electrons are rapidly energized at the shock front, is one of the main open issues in shock physics. Here, we present the first clear evidence for efficient collisionless electron heating at the reverse shock of Tycho's supernova remnant (SNR), revealed by Fe K diagnostics using high-quality X-ray data obtained by the Suzaku satellite. We detect K beta (3p yields 1s) fluorescence emission from low-ionization Fe ejecta excited by energetic thermal electrons at the reverse shock front, which peaks at a smaller radius than Fe K alpha (2p yields 1s) emission dominated by a relatively highly ionized component. Comparisons with our hydrodynamical simulations imply instantaneous electron heating to a temperature 1000 times higher than expected from Coulomb collisions alone. The unique environment of the reverse shock, which is propagating with a high Mach number into rarefied ejecta with a low magnetic field strength, puts strong constraints on the physical mechanism responsible for this heating and favors a cross-shock potential created by charge deflection at the shock front. Our sensitive observation also reveals that the reverse shock radius of this SNR is about 10% smaller than the previous measurement using the Fe K alpha morphology from the Chandra observations. Since strong Fe K beta fluorescence is expected only from low-ionization plasma where Fe ions still have many 3p electrons, this feature is key to diagnosing the plasma state and distribution of the immediate postshock ejecta in a young SNR.

Process gg{yields}h{sub 0}{yields}{gamma}{gamma} in the Lee-Wick standard model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krauss, F.; Underwood, T. E. J.; Zwicky, R.

2008-01-01

The process gg{yields}h{sub 0}{yields}{gamma}{gamma} is studied in the Lee-Wick extension of the standard model (LWSM) proposed by Grinstein, O'Connell, and Wise. In this model, negative norm partners for each SM field are introduced with the aim to cancel quadratic divergences in the Higgs mass. All sectors of the model relevant to gg{yields}h{sub 0}{yields}{gamma}{gamma} are diagonalized and results are commented on from the perspective of both the Lee-Wick and higher-derivative formalisms. Deviations from the SM rate for gg{yields}h{sub 0} are found to be of the order of 15%-5% for Lee-Wick masses in the range 500-1000 GeV. Effects on the rate formore » h{sub 0}{yields}{gamma}{gamma} are smaller, of the order of 5%-1% for Lee-Wick masses in the same range. These comparatively small changes may well provide a means of distinguishing the LWSM from other models such as universal extra dimensions where same-spin partners to standard model fields also appear. Corrections to determinations of Cabibbo-Kobayashi-Maskawa (CKM) elements |V{sub t(b,s,d)}| are also considered and are shown to be positive, allowing the possibility of measuring a CKM element larger than unity, a characteristic signature of the ghostlike nature of the Lee-Wick fields.« less

Growth and yield models for central hardwoods

Treesearch

Martin E. Dale; Donald E. Hilt

1989-01-01

Over the last 20 years computers have become an efficient tool to estimate growth and yield. Computerized yield estimates vary from simple approximation or interpolation of traditional normal yield tables to highly sophisticated programs that simulate the growth and yield of each individual tree.

Estimating oak growth and yield

Treesearch

Martin E. Dale; Donald E. Hilt

1989-01-01

Yields from upland oak stands vary widely from stand to stand due to differences in age, site quality, species composition, and stand structure. Cutting history and other past disturbances such as grazing or fire also affect yields.

Single-molecule strong coupling at room temperature in plasmonic nanocavities

NASA Astrophysics Data System (ADS)

Chikkaraddy, Rohit; de Nijs, Bart; Benz, Felix; Barrow, Steven J.; Scherman, Oren A.; Rosta, Edina; Demetriadou, Angela; Fox, Peter; Hess, Ortwin; Baumberg, Jeremy J.

2016-07-01

Photon emitters placed in an optical cavity experience an environment that changes how they are coupled to the surrounding light field. In the weak-coupling regime, the extraction of light from the emitter is enhanced. But more profound effects emerge when single-emitter strong coupling occurs: mixed states are produced that are part light, part matter, forming building blocks for quantum information systems and for ultralow-power switches and lasers. Such cavity quantum electrodynamics has until now been the preserve of low temperatures and complicated fabrication methods, compromising its use. Here, by scaling the cavity volume to less than 40 cubic nanometres and using host-guest chemistry to align one to ten protectively isolated methylene-blue molecules, we reach the strong-coupling regime at room temperature and in ambient conditions. Dispersion curves from more than 50 such plasmonic nanocavities display characteristic light-matter mixing, with Rabi frequencies of 300 millielectronvolts for ten methylene-blue molecules, decreasing to 90 millielectronvolts for single molecules—matching quantitative models. Statistical analysis of vibrational spectroscopy time series and dark-field scattering spectra provides evidence of single-molecule strong coupling. This dressing of molecules with light can modify photochemistry, opening up the exploration of complex natural processes such as photosynthesis and the possibility of manipulating chemical bonds.

Nanoscale Roughness of Faults Explained by the Scale-Dependent Yield Stress of Geologic Materials

NASA Astrophysics Data System (ADS)

Thom, C.; Brodsky, E. E.; Carpick, R. W.; Goldsby, D. L.; Pharr, G.; Oliver, W.

2017-12-01

Despite significant differences in their lithologies and slip histories, natural fault surfaces exhibit remarkably similar scale-dependent roughness over lateral length scales spanning 7 orders of magnitude, from microns to tens of meters. Recent work has suggested that a scale-dependent yield stress may result in such a characteristic roughness, but experimental evidence in favor of this hypothesis has been lacking. We employ an atomic force microscope (AFM) operating in intermittent-contact mode to map the topography of the Corona Heights fault surface. Our experiments demonstrate that the Corona Heights fault exhibits isotropic self-affine roughness with a Hurst exponent of 0.75 +/- 0.05 at all wavelengths from 60 nm to 10 μm. If yield stress controls roughness, then the roughness data predict that yield strength varies with length scale as λ-0.25 +/ 0.05. To test the relationship between roughness and yield stress, we conducted nanoindentation tests on the same Corona Heights sample and a sample of the Yair Fault, a carbonate fault surface that has been previously characterized by AFM. A diamond Berkovich indenter tip was used to indent the samples at a nominally constant strain rate (defined as the loading rate divided by the load) of 0.2 s-1. The continuous stiffness method (CSM) was used to measure the indentation hardness (which is proportional to yield stress) and the elastic modulus of the sample as a function of depth in each test. For both samples, the yield stress decreases with increasing size of the indents, a behavior consistent with that observed for many engineering materials and recently for other geologic materials such as olivine. The magnitude of this "indentation size effect" is best described by a power-law with exponents of -0.12 +/- 0.06 and -0.18 +/- 0.08 for the Corona Heights and Yair Faults, respectively. These results demonstrate a link between surface roughness and yield stress, and suggest that fault geometry is the physical

Fission yield and criticality excursion code

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blanchard, A.

2000-06-30

The ANSI/ANS 8.3 standard allows a maximum yield not to exceed 2 x 10 fissions to calculate requiring the alarm system to be effective. It is common practice to use this allowance or to develop some other yield based on past criticality accident history or excursion experiments. The literature on the subject of yields discusses maximum yields larger and somewhat smaller than the ANS 8.3 permissive value. The ability to model criticality excursions and vary the various parameters to determine a credible maximum yield for operational specific cases has been available for some time but is not in common usemore » by criticality safety specialists. The topic of yields for various solution, metal, oxide powders, etc. in various geometry's and containers has been published by laboratory specialists or university staff and students for many decades but have not been available to practitioners. The need for best-estimate calculations of fission yields with a well-validated criticality excursion code has long been recognized. But no coordinated effort has been made so far to develop a generalized and well-validated excursion code for different types of systems. In this paper, the current practices to estimate fission yields are summarized along with its shortcomings for the 12-Rad zone (at SRS) and Criticality Alarm System (CAS) calculations. Finally the need for a user-friendly excursion code is reemphasized.« less

Climate Variability and Sugarcane Yield in Louisiana.

NASA Astrophysics Data System (ADS)

Greenland, David

2005-11-01

This paper seeks to understand the role that climate variability has on annual yield of sugarcane in Louisiana. Unique features of sugarcane growth in Louisiana and nonclimatic, yield-influencing factors make this goal an interesting and challenging one. Several methods of seeking and establishing the relations between yield and climate variables are employed. First, yield climate relations were investigated at a single research station where crop variety and growing conditions could be held constant and yield relations could be established between a predominant older crop variety and a newer one. Interviews with crop experts and a literature survey were used to identify potential climatic factors that control yield. A statistical analysis was performed using statewide yield data from the American Sugar Cane League from 1963 to 2002 and a climate database. Yield values for later years were adjusted downward to form an adjusted yield dataset. The climate database was principally constructed from daily and monthly values of maximum and minimum temperature and daily and monthly total precipitation for six cooperative weather-reporting stations representative of the area of sugarcane production. The influence of 74 different, though not independent, climate-related variables on sugarcane yield was investigated. The fact that a climate signal exists is demonstrated by comparing mean values of the climate variables corresponding to the upper and lower third of adjusted yield values. Most of these mean-value differences show an intuitively plausible difference between the high- and low-yield years. The difference between means of the climate variables for years corresponding to the upper and lower third of annual yield values for 13 of the variables is statistically significant at or above the 90% level. A correlation matrix was used to identify the variables that had the largest influence on annual yield. Four variables [called here critical climatic variables (CCV

We strongly support childhood immunisation-statement from the European Academy of Paediatrics (EAP).

PubMed

Dornbusch, Hans Juergen; Hadjipanayis, Adamos; Del Torso, Stefano; Mercier, Jean-Christophe; Wyder, Corinne; Schrier, Lenneke; Ross-Russell, Robert; Stiris, Tom; Ludvigsson, Jonas F

2017-05-01

The eradication of smallpox and the elimination of several other infectious diseases from much of the world has provided convincing evidence that vaccines are among the most effective interventions for promoting health. The current scepticism about immunisation among members of the new US administration carries a risk of decreasing immunisation rates also in Europe. While only a small minority of the population are strongly anti-vaccine, their public activities have significantly influenced an uncertainty among the general population about both the safety of and the necessity for vaccination. Therefore, the EAP calls for greater publically available, scientifically supported information on vaccination, particularly targeted at health care providers, for the further development of electronically based immunisation information systems (IIS). We further call on all European countries to work together both in legislative and public health arenas in order to increase vaccination coverage among the paediatric population. In the interest of children and their parents, the EAP expresses its strong support for childhood immunisation and recommended vaccination schedules. We are prepared to work with governments and media and share the extensive evidence demonstrating the effectiveness and safety of vaccines.

The impact of soil moisture extremes and their spatiotemporal variability on Zambian maize yields

NASA Astrophysics Data System (ADS)

Zhao, Y.; Estes, L. D.; Vergopolan, N.

2017-12-01

Food security in sub-Saharan Africa is highly sensitive to climate variability. While it is well understood that extreme heat has substantial negative impacts on crop yield, the impacts of precipitation extremes, particularly over large spatial extents, are harder to quantify. There are three primary reasons for this difficulty, which are (1) lack of high quality, high resolution precipitation data, (2) rainfall data provide incomplete information on plant water availability, the variable that most directly affects crop performance, and (3) the type of rainfall extreme that most affects crop yields varies throughout the crop development stage. With respect to the first reason, the spatial and temporal variation of precipitation is much greater than that of temperature, yet the spatial resolution of rainfall data is typically even coarser than it is for temperature, particularly within Africa. Even if there were high-resolution rainfall data, the amount of water available to crops also depends on other physical factors that affect evapotranspiration, which are strongly influenced by heterogeneity in the land surface related to topography, soil properties, and land cover. In this context, soil moisture provides a better measure of crop water availability than rainfall. Furthermore, soil moisture has significantly different influences on crop yield depending on the crop's growth stage. The goal of this study is to understand how the spatiotemporal scales of soil moisture extremes interact with crops, more specifically, the timing and the spatial scales of extreme events like droughts and flooding. In this study, we simulate daily-1km soil moisture using HydroBlocks - a physically based land surface model - and compare it with precipitation and remote sensing derived maize yields between 2000 and 2016 in Zambia. We use a novel combination of the SCYM (scalable satellite-based yield mapper) method with DSSAT crop model, which is a mechanistic model responsive to water

Transformation in the pharmaceutical industry--a systematic analysis of operational evidence.

PubMed

Shafiei, Nader; Ford, James L; Morecroft, Charles W; Lisboa, Paulo J; Taylor, Mark J; Mouzughi, Yusra

2013-01-01

Through systematic collection and trending of pharmaceutical data, operational evidence to verify existence of 14 factors affecting the ongoing pharmaceutical transformation has been compiled. These 14 factors are termed transformation triggers. The theoretical evidence in support of these triggers is carried forward from a systematic review of the literature that was conducted previously. Trends in operational evidence and the associated theoretical evidence were compared to identify areas of similarity and contrast. Areas of strong correlation between theoretical evidence and operational evidence included four transformation triggers: a fully integrated pharma network, personalized medicine, translational research, and pervasive computing. Key areas of contrast included three transformation triggers-namely, healthcare management focus, adaptive trials, and regulatory enforcement-for which the operational evidence was stronger than the theoretical evidence. The intent of this paper is to provide proof to demonstrate if there is any operational evidence that supports the 14 transformation triggers previously identified during the theoretical part of this research. The theoretical evidence for these triggers was carried forward to this paper for study from an operational perspective. The practical evidence established in this paper was compared with the corresponding theoretical evidence to identify areas of similarity and difference. This resulted in four triggers that had strong relationship between operational and theoretical evidence; they are a fully integrated pharma network, personalized medicine, translational research, and pervasive computing. The areas of difference included three transformation triggers for which the operational evidence was stronger than the theoretical evidence. These were healthcare management focus, adaptive trials, and regulatory enforcement.

Impact of derived global weather data on simulated crop yields.

PubMed

van Wart, Justin; Grassini, Patricio; Cassman, Kenneth G

2013-12-01

Crop simulation models can be used to estimate impact of current and future climates on crop yields and food security, but require long-term historical daily weather data to obtain robust simulations. In many regions where crops are grown, daily weather data are not available. Alternatively, gridded weather databases (GWD) with complete terrestrial coverage are available, typically derived from: (i) global circulation computer models; (ii) interpolated weather station data; or (iii) remotely sensed surface data from satellites. The present study's objective is to evaluate capacity of GWDs to simulate crop yield potential (Yp) or water-limited yield potential (Yw), which can serve as benchmarks to assess impact of climate change scenarios on crop productivity and land use change. Three GWDs (CRU, NCEP/DOE, and NASA POWER data) were evaluated for their ability to simulate Yp and Yw of rice in China, USA maize, and wheat in Germany. Simulations of Yp and Yw based on recorded daily data from well-maintained weather stations were taken as the control weather data (CWD). Agreement between simulations of Yp or Yw based on CWD and those based on GWD was poor with the latter having strong bias and large root mean square errors (RMSEs) that were 26-72% of absolute mean yield across locations and years. In contrast, simulated Yp or Yw using observed daily weather data from stations in the NOAA database combined with solar radiation from the NASA-POWER database were in much better agreement with Yp and Yw simulated with CWD (i.e. little bias and an RMSE of 12-19% of the absolute mean). We conclude that results from studies that rely on GWD to simulate agricultural productivity in current and future climates are highly uncertain. An alternative approach would impose a climate scenario on location-specific observed daily weather databases combined with an appropriate upscaling method. © 2013 John Wiley & Sons Ltd.

Cigarette Filter Ventilation and Smoking Protocol Influence Aldehyde Smoke Yields

PubMed Central

2018-01-01

The WHO study group on tobacco product regulation (TobReg) advised regulating and lowering toxicant levels in cigarette smoke. Aldehydes are one of the chemical classes on the TobReg smoke toxicants priority list. To provide insight in factors determining aldehyde yields, the levels of 12 aldehydes in mainstream cigarette smoke of 11 Dutch brands were quantified. Variations in smoking behavior and cigarette design affecting human exposure to aldehydes were studied by using four different machine testing protocols. Machine smoking was based on the International Standardization Organization (ISO) and Health Canada Intense (HCI) regime, both with and without taping the filter vents. The 11 cigarette brands differed in (i) design and blend characteristics; (ii) tar, nicotine, and carbon monoxide (TNCO) levels; (iii) popularity; and (iv) manufacturer. Cigarette smoke was trapped on a Cambridge filter pad and carboxen cartridge. After being dissolved in methanol/CS2 and derivatization with DNPH, the aldehyde yields were determined using HPLC-DAD. Using an intense smoking regime (increased puff volume, shorter puff interval) significantly increased aldehyde yields, following the pattern: ISO < ISO-taped < HCI-untaped < HCI. For all of the regimes, acetaldehyde and acrolein yields were strongly correlated (r = 0.804). The difference in TNCO and aldehyde levels between regular and highly ventilated low-TNCO cigarettes (as measured using ISO) diminished when smoking intensely; this effect is stronger when combined with taping filter vents. The highly ventilated low-TNCO brands showed six times more aldehyde production per mg nicotine for the intense smoking regimes. In conclusion, acetaldehyde and acrolein can be used as representatives for the class of volatile aldehydes for the different brands and smoking regimes. The aldehyde-to-nicotine ratio increased when highly ventilated cigarettes were smoked intensely, similar to real smokers. Thus, a smoker of highly ventilated

Facile high-yield synthesis of polyaniline nanosticks with intrinsic stability and electrical conductivity.

PubMed

Li, Xin-Gui; Li, Ang; Huang, Mei-Rong

2008-01-01

Chemical oxidative polymerization at 15 degrees C was used for the simple and productive synthesis of polyaniline (PAN) nanosticks. The effect of polymerization media on the yield, size, stability, and electrical conductivity of the PAN nanosticks was studied by changing the concentration and nature of the acid medium and oxidant and by introducing organic solvent. Molecular and supramolecular structure, size, and size distribution of the PAN nanosticks were characterized by UV/Vis and IR spectroscopy, X-ray diffraction, laser particle-size analysis, and transmission electron microscopy. Introduction of organic solvent is advantageous for enhancing the yield of PAN nanosticks but disadvantageous for formation of PAN nanosticks with small size and high conductivity. The concentration and nature of the acid medium have a major influence on the polymerization yield and conductivity of the nanosized PAN. The average diameter and length of PAN nanosticks produced with 2 M HNO(3) and 0.5 M H(2)SO(4) as acid media are about 40 and 300 nm, respectively. The PAN nanosticks obtained in an optimal medium (i.e., 2 M HNO(3)) exhibit the highest conductivity of 2.23 S cm(-1) and the highest yield of 80.7 %. A mechanism of formation of nanosticks instead of nanoparticles is proposed. Nanocomposite films of the PAN nanosticks with poly(vinyl alcohol) show a low percolation threshold of 0.2 wt %, at which the film retains almost the same transparency and strength as pure poly(vinyl alcohol) but 262 000 times the conductivity of pure poly(vinyl alcohol) film. The present synthesis of PAN nanosticks requires no external stabilizer and provides a facile and direct route for fabrication of PAN nanosticks with high yield, controllable size, intrinsic self-stability, strong redispersibility, high purity, and optimizable conductivity.

Climate Effects on Corn Yield in Missouri(.

NASA Astrophysics Data System (ADS)

Hu, Qi; Buyanovsky, Gregory

2003-11-01

Understanding climate effects on crop yield has been a continuous endeavor aiming at improving farming technology and management strategy, minimizing negative climate effects, and maximizing positive climate effects on yield. Many studies have examined climate effects on corn yield in different regions of the United States. However, most of those studies used yield and climate records that were shorter than 10 years and were for different years and localities. Although results of those studies showed various influences of climate on corn yield, they could be time specific and have been difficult to use for deriving a comprehensive understanding of climate effects on corn yield. In this study, climate effects on corn yield in central Missouri are examined using unique long-term (1895 1998) datasets of both corn yield and climate. Major results show that the climate effects on corn yield can only be explained by within-season variations in rainfall and temperature and cannot be distinguished by average growing-season conditions. Moreover, the growing-season distributions of rainfall and temperature for high-yield years are characterized by less rainfall and warmer temperature in the planting period, a rapid increase in rainfall, and more rainfall and warmer temperatures during germination and emergence. More rainfall and cooler-than-average temperatures are key features in the anthesis and kernel-filling periods from June through August, followed by less rainfall and warmer temperatures during the September and early October ripening time. Opposite variations in rainfall and temperature in the growing season correspond to low yield. Potential applications of these results in understanding how climate change may affect corn yield in the region also are discussed.

Synthesis and strong photooxidation power of a supramolecular hybrid comprising a polyoxometalate and Ru(II) polypyridyl complex with zinc(II).

PubMed

Ohashi, Kenji; Takeda, Hiroyuki; Koike, Kazuhide; Ishitani, Osamu

2015-01-01

A novel method for constructing supramolecular hybrids composed of polyoxometalates and photofunctional metal complexes was developed. A Ru(II) complex with phosphonate groups (RuP) strongly interacted with Zn(II) to afford a 2 : 1 trinuclear metal complex ([(RuP)2Zn](3+)). In dimethylsulfoxide, [(RuP)2Zn](3+) strongly interacted with a Keggin-type heteropolyoxometalate (Si-WPOM) to form a 1 : 1 hybrid ([(RuP)2Zn]-POM). Irradiation of [(RuP)2Zn]-POM in the presence of diethanolamine caused rapid accumulation of the one-electron reduced hybrid with a quantum yield of 0.99.

Enhancement of the finite-frequency superfluid response in the pseudogap regime of strongly disordered superconducting films

PubMed Central

Mondal, Mintu; Kamlapure, Anand; Ganguli, Somesh Chandra; Jesudasan, John; Bagwe, Vivas; Benfatto, Lara; Raychaudhuri, Pratap

2013-01-01

The persistence of a soft gap in the density of states above the superconducting transition temperature Tc, the pseudogap, has long been thought to be a hallmark of unconventional high-temperature superconductors. However, in the last few years this paradigm has been strongly revised by increasing experimental evidence for the emergence of a pseudogap state in strongly-disordered conventional superconductors. Nonetheless, the nature of this state, probed primarily through scanning tunneling spectroscopy (STS) measurements, remains partly elusive. Here we show that the dynamic response above Tc, obtained from the complex ac conductivity, is highly modified in the pseudogap regime of strongly disordered NbN films. Below the pseudogap temperature, T*, the superfluid stiffness acquires a strong frequency dependence associated with a marked slowing down of critical fluctuations. When translated into the length-scale of fluctuations, our results suggest a scenario of thermal phase fluctuations between superconducting domains in a strongly disordered s-wave superconductor. PMID:23446946

Enhancement of the finite-frequency superfluid response in the pseudogap regime of strongly disordered superconducting films.

PubMed

Mondal, Mintu; Kamlapure, Anand; Ganguli, Somesh Chandra; Jesudasan, John; Bagwe, Vivas; Benfatto, Lara; Raychaudhuri, Pratap

2013-01-01

The persistence of a soft gap in the density of states above the superconducting transition temperature Tc, the pseudogap, has long been thought to be a hallmark of unconventional high-temperature superconductors. However, in the last few years this paradigm has been strongly revised by increasing experimental evidence for the emergence of a pseudogap state in strongly-disordered conventional superconductors. Nonetheless, the nature of this state, probed primarily through scanning tunneling spectroscopy (STS) measurements, remains partly elusive. Here we show that the dynamic response above Tc, obtained from the complex ac conductivity, is highly modified in the pseudogap regime of strongly disordered NbN films. Below the pseudogap temperature, T*, the superfluid stiffness acquires a strong frequency dependence associated with a marked slowing down of critical fluctuations. When translated into the length-scale of fluctuations, our results suggest a scenario of thermal phase fluctuations between superconducting domains in a strongly disordered s-wave superconductor.

Electron-induced electron yields of uncharged insulating materials

NASA Astrophysics Data System (ADS)

Hoffmann, Ryan Carl

Presented here are electron-induced electron yield measurements from high-resistivity, high-yield materials to support a model for the yield of uncharged insulators. These measurements are made using a low-fluence, pulsed electron beam and charge neutralization to minimize charge accumulation. They show charging induced changes in the total yield, as much as 75%, even for incident electron fluences of <3 fC/mm2, when compared to an uncharged yield. The evolution of the yield as charge accumulates in the material is described in terms of electron recapture, based on the extended Chung and Everhart model of the electron emission spectrum and the dual dynamic layer model for internal charge distribution. This model is used to explain charge-induced total yield modification measured in high-yield ceramics, and to provide a method for determining electron yield of uncharged, highly insulating, high-yield materials. A sequence of materials with progressively greater charge susceptibility is presented. This series starts with low-yield Kapton derivative called CP1, then considers a moderate-yield material, Kapton HN, and ends with a high-yield ceramic, polycrystalline aluminum oxide. Applicability of conductivity (both radiation induced conductivity (RIC) and dark current conductivity) to the yield is addressed. Relevance of these results to spacecraft charging is also discussed.

Genotype × Environment Interactions of Yield Traits in Backcross Introgression Lines Derived from Oryza sativa cv. Swarna/Oryza nivara

PubMed Central

Balakrishnan, Divya; Subrahmanyam, Desiraju; Badri, Jyothi; Raju, Addanki Krishnam; Rao, Yadavalli Venkateswara; Beerelli, Kavitha; Mesapogu, Sukumar; Surapaneni, Malathi; Ponnuswamy, Revathi; Padmavathi, G.; Babu, V. Ravindra; Neelamraju, Sarla

2016-01-01

Advanced backcross introgression lines (BILs) developed from crosses of Oryza sativa var. Swarna/O. nivara accessions were grown and evaluated for yield and related traits. Trials were conducted for consecutive three seasons in field conditions in a randomized complete block design with three replications. Data on yield traits under irrigated conditions were analyzed using the Additive Main Effect and Multiplicative Interaction (AMMI), Genotype and Genotype × Environment Interaction (GGE) and modified rank-sum statistic (YSi) for yield stability. BILs viz., G3 (14S) and G6 (166S) showed yield stability across the seasons along with high mean yield performance. G3 is early in flowering with high yield and has good grain quality and medium height, hence could be recommended for most of the irrigated locations. G6 is a late duration genotype, with strong culm strength, high grain number and panicle weight. G6 has higher yield and stability than Swarna but has Swarna grain type. Among the varieties tested DRRDhan 40 and recurrent parent Swarna showed stability for yield traits across the seasons. The component traits thousand grain weight, panicle weight, panicle length, grain number and plant height explained highest genotypic percentage over environment and interaction factors and can be prioritized to dissect stable QTLs/ genes. These lines were genotyped using microsatellite markers covering the entire rice genome and also using a set of markers linked to previously reported yield QTLs. It was observed that wild derived lines with more than 70% of recurrent parent genome were stable and showed enhanced yield levels compared to genotypes with higher donor genome introgressions. PMID:27807437

Ethiopian Wheat Yield and Yield Gap Estimation: A Spatial Small Area Integrated Data Approach

NASA Astrophysics Data System (ADS)

Mann, M.; Warner, J.

2015-12-01

Despite the collection of routine annual agricultural surveys and significant advances in GIS and remote sensing products, little econometric research has been undertaken in predicting developing nation's agricultural yields. In this paper, we explore the determinants of wheat output per hectare in Ethiopia during the 2011-2013 Meher crop seasons aggregated to the woreda administrative area. Using a panel data approach, combining national agricultural field surveys with relevant GIS and remote sensing products, the model explains nearly 40% of the total variation in wheat output per hectare across the country. The model also identifies specific contributors to wheat yields that include farm management techniques (eg. area planted, improved seed, fertilizer, irrigation), weather (eg. rainfall), water availability (vegetation and moisture deficit indexes) and policy intervention. Our findings suggest that woredas produce between 9.8 and 86.5% of their potential wheat output per hectare given their altitude, weather conditions, terrain, and plant health. At the median, Amhara, Oromiya, SNNP, and Tigray produce 48.6, 51.5, 49.7, and 61.3% of their local attainable yields, respectively. This research has a broad range of applications, especially from a public policy perspective: identifying causes of yield fluctuations, remotely evaluating larger agricultural intervention packages, and analyzing relative yield potential. Overall, the combination of field surveys with spatial data can be used to identify management priorities for improving production at a variety of administrative levels.

Yields of Bacterial Cells from Hydrocarbons

PubMed Central

Wodzinski, Richard S.; Johnson, Marvin J.

1968-01-01

A strain of Nocardia and one of Pseudomonas, both isolated on pristane (2,6,10,14-tetramethylpentadecane), gave cell yields of approximately 100% on n-octadecane and pristane. Both organisms grew more rapidly on the n-octadecane than on the pristane. A mixed culture, isolated on 3-methylheptane, whose two components were identified as species of Pseudomonas and of Nocardia, gave approximately 100% cell yields and grew with generation times of about 5 hr on n-heptane, n-octane, and 2-methylheptane. The generation time on 3-methylheptane was 8.6 hr and the cell yield was only 79%. A strain of Pseudomonas isolated from naphthalene enrichments and one from phenanthrene enrichments both gave a cell yield of 50% on naphthalene. The phenanthrene isolate gave a cell yield of 40% on phenanthrene. A Nocardia species isolated on benzene gave a 79% cell yield on benzene. The generation times of the bacteria isolated on aromatic hydrocarbons were related to the solubility of the aromatic hydrocarbons on which they were grown; the more insoluble hydrocarbons gave slower growth. PMID:5726161

Influence of Different Yield Loci on Failure Prediction with Damage Models

NASA Astrophysics Data System (ADS)

Heibel, S.; Nester, W.; Clausmeyer, T.; Tekkaya, A. E.

2017-09-01

Advanced high strength steels are widely used in the automotive industry to simultaneously improve crash performance and reduce the car body weight. A drawback of these multiphase steels is their sensitivity to damage effects and thus the reduction of ductility. For that reason the Forming Limit Curve is only partially suitable for this class of steels. An improvement in failure prediction can be obtained by using damage mechanics. The objective of this paper is to comparatively review the phenomenological damage model GISSMO and the Enhanced Lemaitre Damage Model. GISSMO is combined with three different yield loci, namely von Mises, Hill48 and Barlat2000 to investigate the influence of the choice of the plasticity description on damage modelling. The Enhanced Lemaitre Model is used with Hill48. An inverse parameter identification strategy for a DP1000 based on stress-strain curves and optical strain measurements of shear, uniaxial, notch and (equi-)biaxial tension tests is applied to calibrate the models. A strong dependency of fracture strains on the choice of yield locus can be observed. The identified models are validated on a cross-die cup showing ductile fracture with slight necking.

Feature long axis size and local luminance contrast determine ship target acquisition performance: strong evidence for the TOD case

NASA Astrophysics Data System (ADS)

Bijl, Piet; Toet, Alexander; Kooi, Frank L.

2016-10-01

Visual images of a civilian target ship on a sea background were produced using a CAD model. The total set consisted of 264 images and included 3 different color schemes, 2 ship viewing aspects, 5 sun illumination conditions, 2 sea reflection values, 2 ship positions with respect to the horizon and 3 values of atmospheric contrast reduction. In a perception experiment, the images were presented on a display in a long darkened corridor. Observers were asked to indicate the range at which they were able to detect the ship and classify the following 5 ship elements: accommodation, funnel, hull, mast, and hat above the bridge. This resulted in a total of 1584 Target Acquisition (TA) range estimates for two observers. Next, the ship contour, ship elements and corresponding TA ranges were analyzed applying several feature size and contrast measures. Most data coincide on a contrast versus angular size plot using (1) the long axis as characteristic ship/ship feature size and (2) local Weber contrast as characteristic ship/ship feature contrast. Finally, the data were compared with a variety of visual performance functions assumed to be representative for Target Acquisition: the TOD (Triangle Orientation Discrimination), MRC (Minimum Resolvable Contrast), CTF (Contrast Threshold Function), TTP (Targeting Task Performance) metric and circular disc detection data for the unaided eye (Blackwell). The results provide strong evidence for the TOD case: both position and slope of the TOD curve match the ship detection and classification data without any free parameter. In contrast, the MRC and CTF are too steep, the TTP and disc detection curves are too shallow and all these curves need an overall scaling factor in order to coincide with the ship and ship feature recognition data.

Tracking dissociation dynamics of strong-field ionized 1,2-dibromoethane with femtosecond XUV transient absorption spectroscopy.

PubMed

Chatterley, Adam S; Lackner, Florian; Neumark, Daniel M; Leone, Stephen R; Gessner, Oliver

2016-06-07

Using femtosecond time-resolved extreme ultraviolet absorption spectroscopy, the dissociation dynamics of the haloalkane 1,2-dibromoethane (DBE) have been explored following strong field ionization by femtosecond near infrared pulses at intensities between 7.5 × 10(13) and 2.2 × 10(14) W cm(-2). The major elimination products are bromine atoms in charge states of 0, +1, and +2. The charge state distribution is strongly dependent on the incident NIR intensity. While the yield of neutral fragments is essentially constant for all measurements, charged fragment yields grow rapidly with increasing NIR intensities with the most pronounced effect observed for Br(++). However, the appearance times of all bromine fragments are independent of the incident field strength; these are found to be 320 fs, 70 fs, and 30 fs for Br˙, Br(+), and Br(++), respectively. Transient molecular ion features assigned to DBE(+) and DBE(++) are observed, with dynamics linked to the production of Br(+) products. Neutral Br˙ atoms are produced on a timescale consistent with dissociation of DBE(+) ions on a shallow potential energy surface. The appearance of Br(+) ions by dissociative ionization is also seen, as evidenced by the simultaneous decay of a DBE(+) ionic species. Dicationic Br(++) products emerge within the instrument response time, presumably from Coulomb explosion of triply charged DBE.

Tracking dissociation dynamics of strong-field ionized 1,2-dibromoethane with femtosecond XUV transient absorption spectroscopy

DOE PAGES

Chatterley, Adam S.; Lackner, Florian; Neumark, Daniel M.; ...

2016-05-11

Using femtosecond time-resolved extreme ultraviolet absorption spectroscopy, the dissociation dynamics of the haloalkane 1,2-dibromoethane (DBE) have been explored following strong field ionization by femtosecond near infrared pulses at intensities between 7.5 × 10 13 and 2.2 × 10 14 W cm -2. The major elimination products are bromine atoms in charge states of 0, +1, and +2. The charge state distribution is strongly dependent on the incident NIR intensity. While the yield of neutral fragments is essentially constant for all measurements, charged fragment yields grow rapidly with increasing NIR intensities with the most pronounced effect observed for Br ++. However,more » the appearance times of all bromine fragments are independent of the incident field strength; these are found to be 320 fs, 70 fs, and 30 fs for Br˙, Br +, and Br ++, respectively. Transient molecular ion features assigned to DBE + and DBE ++ are observed, with dynamics linked to the production of Br + products. Neutral Br˙ atoms are produced on a timescale consistent with dissociation of DBE + ions on a shallow potential energy surface. The appearance of Br + ions by dissociative ionization is also seen, as evidenced by the simultaneous decay of a DBE + ionic species. Dicationic Br ++ products emerge within the instrument response time, presumably from Coulomb explosion of triply charged DBE.« less

Resonant Thermalization of Periodically Driven Strongly Correlated Electrons

NASA Astrophysics Data System (ADS)

Peronaci, Francesco; Schiró, Marco; Parcollet, Olivier

2018-05-01

We study the dynamics of the Fermi-Hubbard model driven by a time-periodic modulation of the interaction within nonequilibrium dynamical mean-field theory. For moderate interaction, we find clear evidence of thermalization to a genuine infinite-temperature state with no residual oscillations. Quite differently, in the strongly correlated regime, we find a quasistationary extremely long-lived state with oscillations synchronized with the drive (Floquet prethermalization). Remarkably, the nature of this state dramatically changes upon tuning the drive frequency. In particular, we show the existence of a critical frequency at which the system rapidly thermalizes despite the large interaction. We characterize this resonant thermalization and provide an analytical understanding in terms of a breakdown of the periodic Schrieffer-Wolff transformation.

A Novel Approach for Forecasting Crop Production and Yield Using Remotely Sensed Satellite Images

NASA Astrophysics Data System (ADS)

Singh, R. K.; Budde, M. E.; Senay, G. B.; Rowland, J.

2017-12-01

Forecasting crop production in advance of crop harvest plays a significant role in drought impact management, improved food security, stabilizing food grain market prices, and poverty reduction. This becomes essential, particularly in Sub-Saharan Africa, where agriculture is a critical source of livelihoods, but lacks good quality agricultural statistical data. With increasing availability of low cost satellite data, faster computing power, and development of modeling algorithms, remotely sensed images are becoming a common source for deriving information for agricultural, drought, and water management. Many researchers have shown that the Normalized Difference Vegetation Index (NDVI), based on red and near-infrared reflectance, can be effectively used for estimating crop production and yield. Similarly, crop production and yield have been closely related to evapotranspiration (ET) also as there are strong linkages between production/yield and transpiration based on plant physiology. Thus, we combined NDVI and ET information from remotely sensed images for estimating total production and crop yield prior to crop harvest for Niger and Burkina Faso in West Africa. We identified the optimum time (dekads 23-29) for cumulating NDVI and ET and developed a new algorithm for estimating crop production and yield. We used the crop data from 2003 to 2008 to calibrate our model and the data from 2009 to 2013 for validation. Our results showed that total crop production can be estimated within 5% of actual production (R2 = 0.98) about 30-45 days before end of the harvest season. This novel approach can be operationalized to provide a valuable tool to decision makers for better drought impact management in drought-prone regions of the world.

PREFACE: Strongly Coupled Coulomb Systems Strongly Coupled Coulomb Systems

NASA Astrophysics Data System (ADS)

Neilson, David; Senatore, Gaetano

2009-05-01

This special issue contains papers presented at the International Conference on Strongly Coupled Coulomb Systems (SCCS), held from 29 July-2 August 2008 at the University of Camerino. Camerino is an ancient hill-top town located in the Apennine mountains of Italy, 200 kilometres northeast of Rome, with a university dating back to 1336. The Camerino conference was the 11th in a series which started in 1977: 1977: Orleans-la-Source, France, as a NATO Advanced Study Institute on Strongly Coupled Plasmas (hosted by Marc Feix and Gabor J Kalman) 1982: Les Houches, France (hosted by Marc Baus and Jean-Pierre Hansen) 1986: Santa Cruz, California, USA (hosted by Forrest J Rogers and Hugh E DeWitt) 1989: Tokyo, Japan (hosted by Setsuo Ichimaru) 1992: Rochester, New York, USA (hosted by Hugh M Van Horn and Setsuo Ichimaru) 1995: Binz, Germany (hosted by Wolf Dietrich Kraeft and Manfred Schlanges) 1997: Boston, Massachusetts, USA (hosted by Gabor J Kalman) 1999: St Malo, France (hosted by Claude Deutsch and Bernard Jancovici) 2002: Santa Fe, New Mexico, USA (hosted by John F Benage and Michael S Murillo) 2005: Moscow, Russia (hosted by Vladimir E Fortov and Vladimir Vorob'ev). The name of the series was changed in 1996 from Strongly Coupled Plasmas to Strongly Coupled Coulomb Systems to reflect a wider range of topics. 'Strongly Coupled Coulomb Systems' encompasses diverse many-body systems and physical conditions. The purpose of the conferences is to provide a regular international forum for the presentation and discussion of research achievements and ideas relating to a variety of plasma, liquid and condensed matter systems that are dominated by strong Coulomb interactions between their constituents. Each meeting has seen an evolution of topics and emphases that have followed new discoveries and new techniques. The field has continued to see new experimental tools and access to new strongly coupled conditions, most recently in the areas of warm matter, dusty plasmas

Epidemiologic evidence regarding vitamin C and cancer.

PubMed

Block, G

1991-12-01

Approximately 90 epidemiologic studies have examined the role of vitamin C or vitamin-C-rich foods in cancer prevention, and the vast majority have found statistically significant protective effects. Evidence is strong for cancers of the esophagus, oral cavity, stomach, and pancreas. There is also substantial evidence of a protective effect in cancers of the cervix, rectum, and breast. Even in lung cancer, for which carotenoids show a consistent protective effect, there is recent evidence of a role for vitamin C. Vitamin C is an important antioxidant and free radical scavenger in plasma and acts to regenerate active vitamin E in lipid membranes. Although several different factors in fruits and vegetables probably act jointly, the epidemiologic and biochemical evidence indicate an important role for vitamin C.

The potential for using canopy spectral reflectance as an indirect selection tool for yield improvement in winter wheat

NASA Astrophysics Data System (ADS)

Prasad, Bishwajit

Scope and methods of study. Complementing breeding effort by deploying alternative methods of identifying higher yielding genotypes in a wheat breeding program is important for obtaining greater genetic gains. Spectral reflectance indices (SRI) are one of the many indirect selection tools that have been reported to be associated with different physiological process of wheat. A total of five experiments (a set of 25 released cultivars from winter wheat breeding programs of the U.S. Great Plains and four populations of randomly derived recombinant inbred lines having 25 entries in each population) were conducted in two years under Great Plains winter wheat rainfed environments at Oklahoma State University research farms. Grain yield was measured in each experiment and biomass was measured in three experiments at three growth stages (booting, heading, and grainfilling). Canopy spectral reflectance was measured at three growth stages and eleven SRI were calculated. Correlation (phenotypic and genetic) between grain yield and SRI, biomass and SRI, heritability (broad sense) of the SRI and yield, response to selection and correlated response, relative selection efficiency of the SRI, and efficiency in selecting the higher yielding genotypes by the SRI were assessed. Findings and conclusions. The genetic correlation coefficients revealed that the water based near infrared indices (WI and NWI) were strongly associated with grain yield and biomass production. The regression analysis detected a linear relationship between the water based indices with grain yield and biomass. The two newly developed indices (NWI-3 and NWI-4) gave higher broad sense heritability than grain yield, higher direct response to selection compared to grain yield, correlated response equal to or higher than direct response for grain yield, relative selection efficiency greater than one, and higher efficiency in selecting higher yielding genotypes. Based on the overall genetic analysis required to

Crop status evaluations and yield predictions

NASA Technical Reports Server (NTRS)

Haun, J. R.

1976-01-01

One phase of the large area crop inventory project is presented. Wheat yield models based on the input of environmental variables potentially obtainable through the use of space remote sensing were developed and demonstrated. By the use of a unique method for visually qualifying daily plant development and subsequent multifactor computer analyses, it was possible to develop practical models for predicting crop development and yield. Development of wheat yield prediction models was based on the discovery that morphological changes in plants are detected and quantified on a daily basis, and that this change during a portion of the season was proportional to yield.

Calculation of the total electron excitation cross section in the Born approximation using Slater wave functions for the Li (2s yields 2p), Li (2s yields 3p), Na (3s yields 4p), Mg (3p yields 4s), Ca (4s yields 4p) and K (4s yields 4p) excitations. M.S. Thesis

NASA Technical Reports Server (NTRS)

Simsic, P. L.

1974-01-01

Excitation of neutral atoms by inelastic scattering of incident electrons in gaseous nebulae were investigated using Slater Wave functions to describe the initial and final states of the atom. Total cross sections using the Born Approximation are calculated for: Li(2s yields 2p), Na(3s yields 4p), k(4s yields 4p). The intensity of emitted radiation from gaseous nebulae is also calculated, and Maxwell distribution is employed to average the kinetic energy of electrons.

Meeting the demand for crop production: the challenge of yield decline in crops grown in short rotations.

PubMed

Bennett, Amanda J; Bending, Gary D; Chandler, David; Hilton, Sally; Mills, Peter

2012-02-01

There is a trend world-wide to grow crops in short rotation or in monoculture, particularly in conventional agriculture. This practice is becoming more prevalent due to a range of factors including economic market trends, technological advances, government incentives, and retailer and consumer demands. Land-use intensity will have to increase further in future in order to meet the demands of growing crops for both bioenergy and food production, and long rotations may not be considered viable or practical. However, evidence indicates that crops grown in short rotations or monoculture often suffer from yield decline compared to those grown in longer rotations or for the first time. Numerous factors have been hypothesised as contributing to yield decline, including biotic factors such as plant pathogens, deleterious rhizosphere microorganisms, mycorrhizas acting as pathogens, and allelopathy or autotoxicity of the crop, as well as abiotic factors such as land management practices and nutrient availability. In many cases, soil microorganisms have been implicated either directly or indirectly in yield decline. Although individual factors may be responsible for yield decline in some cases, it is more likely that combinations of factors interact to cause the problem. However, evidence confirming the precise role of these various factors is often lacking in field studies due to the complex nature of cropping systems and the numerous interactions that take place within them. Despite long-term knowledge of the yield-decline phenomenon, there are few tools to counteract it apart from reverting to longer crop rotations or break crops. Alternative cropping and management practices such as double-cropping or inter-cropping, tillage and organic amendments may prove valuable for combating some of the negative effects seen when crops are grown in short rotation. Plant breeding continues to be important, although this does require a specific breeding target to be identified. This

Strongly anomalous diffusion in sheared magnetic configurations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vanden Eijnden, E.; Balescu, R.

1996-03-01

The statistical behavior of magnetic lines in a sheared magnetic configuration with reference surface {ital x}=0 is investigated within the framework of the kinetic theory. A Liouville equation is associated with the equations of motion of the stochastic magnetic lines. After averaging over an ensemble of realizations, it yields a convection-diffusion equation within the quasilinear approximation. The diffusion coefficients are space dependent and peaked around the reference surface {ital x}=0. Due to the shear, the diffusion of lines away from the reference surface is slowed down. The behavior of the lines is asymptotically strongly non-Gaussian. The reference surface acts likemore » an attractor around which the magnetic lines spread with an effective subdiffusive behavior. Comparison is also made with more usual treatments based on the study of the first two moments equations. For sheared systems, it is explicitly shown that the Corrsin approximation assumed in the latter approach is no longer valid. It is also concluded that the diffusion coefficients cannot be derived from the mean square displacement of the magnetic lines in an inhomogeneous medium. {copyright} {ital 1996 American Institute of Physics.}« less

Breeding cassava for higher yield

USDA-ARS?s Scientific Manuscript database

Cassava is a root crop grown for food and for starch production. Breeding progress is slowed by asexual production and high levels of heterozygosity. Germplasm resources are rich and accessible to breeders through genebanks worldwide. Breeding objectives include high root yield, yield stability, dis...

Kinetics of lipogenic genes expression in milk purified mammary epithelial cells (MEC) across lactation and their correlation with milk and fat yield in buffalo.

PubMed

Yadav, Poonam; Kumar, Parveen; Mukesh, Manishi; Kataria, R S; Yadav, Anita; Mohanty, A K; Mishra, B P

2015-04-01

Expression patterns of lipogenic genes (LPL, ABCG2, ACSS2, ACACA, SCD, BDH, LIPIN1, SREBF1, PPARα and PPARγ) were studied in milk purified MEC across different stages of lactation (15, 30, 45, 60, 90, 120 and 240 days relative to parturition) in buffalo. PPARα was the most abundant gene while ABCG2 and ACSS2 had moderate level of expression; whereas expression of SREBF and PPARγ was very low. The expression patterns of some genes (BDH1, ACSS2, and LIPIN1) across lactation were positively correlated with milk yield while negatively correlated with fat yield. SCD also showed weak correlation with milk yield (p, 0.53) and fat yield (p, -0.47). On the other hand, expression pattern of ACACA was negatively correlated with milk yield (p, -0.88) and positively correlated with fat yield (p, 0.62). Strong correlation was observed between genes involved in de novo milk fat synthesis (BDH1, ACSS2, LIPIN2 and SCD) and milk yield. Copyright © 2015 Elsevier Ltd. All rights reserved.

Grapevine canopy reflectance and yield

NASA Technical Reports Server (NTRS)

Minden, K. A.; Philipson, W. R.

1982-01-01

Field spectroradiometric and airborne multispectral scanner data were applied in a study of Concord grapevines. Spectroradiometric measurements of 18 experimental vines were collected on three dates during one growing season. Spectral reflectance, determined at 30 intervals from 0.4 to 1.1 microns, was correlated with vine yield, pruning weight, clusters/vine, and nitrogen input. One date of airborne multispectral scanner data (11 channels) was collected over commercial vineyards, and the average radiance values for eight vineyard sections were correlated with the corresponding average yields. Although some correlations were significant, they were inadequate for developing a reliable yield prediction model.

Evidence for magnetic Weyl fermions in a correlated metal

NASA Astrophysics Data System (ADS)

Kuroda, K.; Tomita, T.; Suzuki, M.-T.; Bareille, C.; Nugroho, A. A.; Goswami, P.; Ochi, M.; Ikhlas, M.; Nakayama, M.; Akebi, S.; Noguchi, R.; Ishii, R.; Inami, N.; Ono, K.; Kumigashira, H.; Varykhalov, A.; Muro, T.; Koretsune, T.; Arita, R.; Shin, S.; Kondo, Takeshi; Nakatsuji, S.

2017-11-01

Weyl fermions have been observed as three-dimensional, gapless topological excitations in weakly correlated, inversion-symmetry-breaking semimetals. However, their realization in spontaneously time-reversal-symmetry-breaking phases of strongly correlated materials has so far remained hypothetical. Here, we report experimental evidence for magnetic Weyl fermions in Mn3Sn, a non-collinear antiferromagnet that exhibits a large anomalous Hall effect, even at room temperature. Detailed comparison between angle-resolved photoemission spectroscopy (ARPES) measurements and density functional theory (DFT) calculations reveals significant bandwidth renormalization and damping effects due to the strong correlation among Mn 3d electrons. Magnetotransport measurements provide strong evidence for the chiral anomaly of Weyl fermions--namely, the emergence of positive magnetoconductance only in the presence of parallel electric and magnetic fields. Since weak magnetic fields (approximately 10 mT) are adequate to control the distribution of Weyl points and the large fictitious fields (equivalent to approximately a few hundred T) produced by them in momentum space, our discovery lays the foundation for a new field of science and technology involving the magnetic Weyl excitations of strongly correlated electron systems such as Mn3Sn.

Product yield-detected ESR on magnetic field-dependent photoreduction of quinones in SDS micellar solution

NASA Astrophysics Data System (ADS)

Okazaki, M.; Sakata, S.; Konaka, R.; Shiga, T.

1987-06-01

Transient free radicals in the magnetic field-dependent photoreduction of quinones (menadione or anthraquinone) in a sodium dodecyl sulfate (SDS) micellar solution, were converted to stable nitroxide radicals by the ``spin trapping'' technique with or without the microwave irradiation. Upon irradiating the microwave at 160 mW, the product yield (``spin adduct'' of the alkyl radical generated from SDS molecule) decreased by up to 14% at certain magnetic fields in a resonant manner. Although only one component of the postulated radical pair was converted to the spin adduct, the decrease in the yield as a function of external magnetic field revealed the ESR spectra of both component radicals of the radical pair, i.e., the semiquinone radical and the alkyl radical from SDS. This experiment not only gives the direct evidence for the radical pair model, but also suggests the possibility for this method to be applied in controlling the chemical reactions by the microwave. A simple calculation was made to simulate the observed ``product yield-detected ESR.'' Agreements were achieved semiquantitatively between the observed reductions in the spin adduct yields and those calculated. The estimated exchange interaction between the component radicals in the radical pair of the present systems was lower than 0.3 mT.

Epidemiology of osteoarthritis: state of the evidence

PubMed Central

Allen, Kelli D.; Golightly, Yvonne M.

2015-01-01

Purpose of review This review focuses on recent studies of osteoarthritis epidemiology, including research on prevalence, incidence, and a broad array of potential risk factors at the person level and joint level. Recent findings Studies continue to illustrate the high impact of osteoarthritis worldwide, with increasing incidence. Person-level risk factors with strong evidence regarding osteoarthritis incidence and/or progression include age, sex, socioeconomic status, family history, and obesity. Joint-level risk factors with strong evidence for incident osteoarthritis risk include injury and occupational joint loading; the associations of injury and joint alignment with osteoarthritis progression are compelling. Moderate levels of physical activity have not been linked to increased osteoarthritis risk. Some topics of high recent interest or emerging evidence for association with osteoarthritis include metabolic pathways, vitamins, joint shape, bone density, limb length inequality, muscle strength and mass, and early structural damage. Summary Osteoarthritis is a complex, multifactorial disease, and there is still much to learn regarding mechanisms underlying incidence and progression. However, there are several known modifiable and preventable risk factors, including obesity and joint injury; efforts to mitigate these risks can help to lessen the impact of osteoarthritis. PMID:25775186

Synthesis and characterization of poly (dihydroxybiphenyl borate) with high char yield for high-performance thermosetting resins

NASA Astrophysics Data System (ADS)

Wang, Shujuan; Xing, Xiaolong; Li, Jian; Jing, Xinli

2018-01-01

The objective of the current work is to synthesize novel boron-containing polymers with excellent thermal resistance, and reveal the structure and the reason for the high char yield. Thus, poly (dihydroxybiphenyl borate) (PDDB) with a more rigid molecular chain, was successfully synthesized using 4,4‧-dihydroxybiphenyl and boric acid. Structural characterizations of the prepared PDDB were performed via NMR, FTIR, XPS, and XRD analyses. The results reveal that PDDB consists of aromatic, Phsbnd Osbnd B and Bsbnd Osbnd B structures as well as a small number of boron hydroxyl and phenolic hydroxyl groups. PDDB shows good solubility in strong polar solvents, which is of great importance for the modification of thermosetting resins. TGA combined with DSC were employed to evaluate the thermal properties of PDDB, and increases in the glass transition temperature (Tg) and char yield were observed with increased boron content. Tg and char yield of PDDB (800 °C, nitrogen atmosphere) reached up to 219 °C and 66.5%, respectively. PDDB was extensively characterized during pyrolysis to reveal the high char yield of PDDB. As briefly discussed, the boron oxide and boron carbide that formed during pyrolysis play a crucial role in the high char yield of PDDB, which reduces the release of volatile carbon dioxide and carbon. This research suggests that PDDB has great potential as a novel modified agent for the improvement of the comprehensive performance of thermosetting resins to broaden their applicability in the field of advanced composites.

Growth and yield of shortleaf pine

Treesearch

Paul A. Murphy

1986-01-01

A survey of available growth and yield information for shortleaf pine (Pinus echinata Mill.) is given. The kinds of studies and data sources that produce this information are also evaluated, and an example of how a growth and yield model can be used to answer management questions is illustrated. Guidelines are given for using growth and yield models, and needs for...

Consequences of waterlogging in cotton and opportunities for mitigation of yield losses

PubMed Central

Najeeb, Ullah; Bange, Michael P.; Tan, Daniel K. Y.; Atwell, Brian J.

2015-01-01

controlling ethylene biosynthesis are strong candidates to minimize yield losses in waterlogged cotton crops. Other key pathways of anoxia tolerance are also cited as potential tools towards waterlogging-tolerant cotton genotypes. PMID:26194168

Quantifying yield gaps in wheat production in Russia

NASA Astrophysics Data System (ADS)

Schierhorn, Florian; Faramarzi, Monireh; Prishchepov, Alexander V.; Koch, Friedrich J.; Müller, Daniel

2014-08-01

Crop yields must increase substantially to meet the increasing demands for agricultural products. Crop yield increases are particularly important for Russia because low crop yields prevail across Russia’s widespread and fertile land resources. However, reliable data are lacking regarding the spatial distribution of potential yields in Russia, which can be used to determine yield gaps. We used a crop growth model to determine the yield potentials and yield gaps of winter and spring wheat at the provincial level across European Russia. We modeled the annual yield potentials from 1995 to 2006 with optimal nitrogen supplies for both rainfed and irrigated conditions. Overall, the results suggest yield gaps of 1.51-2.10 t ha-1, or 44-52% of the yield potential under rainfed conditions. Under irrigated conditions, yield gaps of 3.14-3.30 t ha-1, or 62-63% of the yield potential, were observed. However, recurring droughts cause large fluctuations in yield potentials under rainfed conditions, even when the nitrogen supply is optimal, particularly in the highly fertile black soil areas of southern European Russia. The highest yield gaps (up to 4 t ha-1) under irrigated conditions were detected in the steppe areas in southeastern European Russia along the border of Kazakhstan. Improving the nutrient and water supply and using crop breeds that are adapted to the frequent drought conditions are important for reducing yield gaps in European Russia. Our regional assessment helps inform policy and agricultural investors and prioritize research that aims to increase crop production in this important region for global agricultural markets.

Diverse regulatory factors associate with flowering time and yield responses in winter-type Brassica napus.

PubMed

Schiessl, Sarah; Iniguez-Luy, Federico; Qian, Wei; Snowdon, Rod J

2015-09-29

Flowering time, plant height and seed yield are strongly influenced by climatic and day-length adaptation in crop plants. To investigate these traits under highly diverse field conditions in the important oilseed crop Brassica napus, we performed a genome-wide association study using data from diverse agroecological environments spanning three continents. A total of 158 European winter-type B.napus inbred lines were genotyped with 21,623 unique, single-locus single-nucleotide polymorphism (SNP) markers using the Brassica 60 K-SNP Illumina® Infinium consortium array. Phenotypic associations were calculated in the panel over the years 2010-2012 for flowering time, plant height and seed yield in 5 highly diverse locations in Germany, China and Chile, adding up to 11 diverse environments in total. We identified 101 genome regions associating with the onset of flowering, 69 with plant height, 36 with seed yield and 68 cross-trait regions with potential adaptive value. Within these regions, B.napus orthologs for a number of candidate adaptation genes were detected, including central circadian clock components like CIRCADIAN CLOCK- ASSOCIATED 1 (Bna.CCA1) and the important flowering-time regulators FLOWERING LOCUS T (Bna.FT) and FRUITFUL (Bna.FUL). Gene ontology (GO) enrichment analysis of candidate regions suggested that selection of genes involved in post-transcriptional and epigenetic regulation of flowering time may play a potential role in adaptation of B. napus to highly divergent environments. The classical flowering time regulators Bna.FLC and Bna.CO were not found among the candidate regions, although both show functional variation. Allelic effects were additive for plant height and yield, but not for flowering time. The scarcity of positive minor alleles for yield in this breeding pool points to a lack of diversity for adaptation that could restrict yield gain in the face of environmental change. Our study provides a valuable framework to further improve the

500  Gb/s free-space optical transmission over strong atmospheric turbulence channels.

PubMed

Qu, Zhen; Djordjevic, Ivan B

2016-07-15

We experimentally demonstrate a high-spectral-efficiency, large-capacity, featured free-space-optical (FSO) transmission system by using low-density, parity-check (LDPC) coded quadrature phase shift keying (QPSK) combined with orbital angular momentum (OAM) multiplexing. The strong atmospheric turbulence channel is emulated by two spatial light modulators on which four randomly generated azimuthal phase patterns yielding the Andrews spectrum are recorded. The validity of such an approach is verified by reproducing the intensity distribution and irradiance correlation function (ICF) from the full-scale simulator. Excellent agreement of experimental, numerical, and analytical results is found. To reduce the phase distortion induced by the turbulence emulator, the inexpensive wavefront sensorless adaptive optics (AO) is used. To deal with remaining channel impairments, a large-girth LDPC code is used. To further improve the aggregate data rate, the OAM multiplexing is combined with WDM, and 500 Gb/s optical transmission over the strong atmospheric turbulence channels is demonstrated.

Water-Soluble Polymers with Strong Photoluminescence through an Eco-Friendly and Low-Cost Route.

PubMed

Guo, Zhaoyan; Ru, Yue; Song, Wenbo; Liu, Zhenjie; Zhang, Xiaohong; Qiao, Jinliang

2017-07-01

Photoluminescence (PL) of nonconjugated polymers brings a favorable opportunity for low-cost and nontoxic luminescent materials, while most of them still exhibit relatively weak emission. Strong PL from poly[(maleic anhydride)-alt-(vinyl acetate)] (PMV) from low-cost monomer has been found in organic solvents, yet the necessity of noxious solvents would hinder its practical applications. Herein, through a novel, eco-friendly, and one-step route, PMV-derived PL polymers can be fabricated with the highest quantum yield of 87% among water-soluble nonconjugated PL polymers ever reported. These PMV-derived polymers emit strong blue emission in both solutions and solids, and can be transformed into red-emission agents easily. These PL polymers exhibit application potentials in light-conversion agricultural films. It is assumed that this work not only puts forward a convenient preparation routine for nonconjugated polymers with high PL, but also provides an industrial application possibility for them. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Eyes are on us, but nobody cares: are eye cues relevant for strong reciprocity?

PubMed Central

Fehr, Ernst; Schneider, Frédéric

2010-01-01

Strong reciprocity is characterized by the willingness to altruistically reward cooperative acts and to altruistically punish norm-violating, defecting behaviours. Recent evidence suggests that subtle reputation cues, such as eyes staring at subjects during their choices, may enhance prosocial behaviour. Thus, in principle, strong reciprocity could also be affected by eye cues. We investigate the impact of eye cues on trustees' altruistic behaviour in a trust game and find zero effect. Neither the subjects who are classified as prosocial nor the subjects who are classified as selfish respond to these cues. In sharp contrast to the irrelevance of subtle reputation cues for strong reciprocity, we find a large effect of explicit, pecuniary reputation incentives on the trustees' prosociality. Trustees who can acquire a good reputation that benefits them in future interactions honour trust much more than trustees who cannot build a good reputation. These results cast doubt on hypotheses suggesting that strong reciprocity is easily malleable by implicit reputation cues not backed by explicit reputation incentives. PMID:20031986

Differential adaptation of two varieties of common bean to abiotic stress: I. Effects of drought on yield and photosynthesis.

PubMed

Lizana, Carolina; Wentworth, Mark; Martinez, Juan P; Villegas, Daniel; Meneses, Rodrigo; Murchie, Erik H; Pastenes, Claudio; Lercari, Bartolomeo; Vernieri, Paulo; Horton, Peter; Pinto, Manuel

2006-01-01

The yield of 24 commercial varieties and accessions of common bean (Phaseolus vulgaris) has been determined at different sites in Chile and Bolivia. Statistical analysis was performed in order to characterize whether a particular variety was more or less stable in yield under different environmental conditions. Amongst these, two varieties have been identified for more detailed study: one variety has a higher than average yield under unstressed conditions but is strongly affected by stress, and another has a reduced yield under unstressed conditions but is less affected by stress. The contrasting rate of abscission of the reproductive organs under drought stress was clearly consistent with these differences. The more tolerant genotype shows a great deal of plasticity at the biochemical and cellular level when exposed to drought stress, in terms of stomatal conductance, photosynthetic rate, abscisic acid synthesis, and resistance to photoinhibition. By contrast, the former lacks such plasticity, but shows an enhanced tendency for a morphological response, the movement of leaves, which appears to be its principal response to drought stress.

Argentina soybean yield model

NASA Technical Reports Server (NTRS)

Callis, S. L.; Sakamoto, C.

1984-01-01

A model based on multiple regression was developed to estimate soybean yields for the country of Argentina. A meteorological data set was obtained for the country by averaging data for stations within the soybean growing area. Predictor variables for the model were derived from monthly total precipitation and monthly average temperature. A trend variable was included for the years 1969 to 1978 since an increasing trend in yields due to technology was observed between these years.

Using a matrix-analytical approach to synthesizing evidence solved incompatibility problem in the hierarchy of evidence.

PubMed

Walach, Harald; Loef, Martin

2015-11-01

The hierarchy of evidence presupposes linearity and additivity of effects, as well as commutativity of knowledge structures. It thereby implicitly assumes a classical theoretical model. This is an argumentative article that uses theoretical analysis based on pertinent literature and known facts to examine the standard view of methodology. We show that the assumptions of the hierarchical model are wrong. The knowledge structures gained by various types of studies are not sequentially indifferent, that is, do not commute. External validity and internal validity are at least partially incompatible concepts. Therefore, one needs a different theoretical structure, typical of quantum-type theories, to model this situation. The consequence of this situation is that the implicit assumptions of the hierarchical model are wrong, if generalized to the concept of evidence in total. The problem can be solved by using a matrix-analytical approach to synthesizing evidence. Here, research methods that produce different types of evidence that complement each other are synthesized to yield the full knowledge. We show by an example how this might work. We conclude that the hierarchical model should be complemented by a broader reasoning in methodology. Copyright © 2015 Elsevier Inc. All rights reserved.

Design of Donor Polymers with Strong Temperature-Dependent Aggregation Property for Efficient Organic Photovoltaics.

PubMed

Hu, Huawei; Chow, Philip C Y; Zhang, Guangye; Ma, Tingxuan; Liu, Jing; Yang, Guofang; Yan, He

2017-10-17

.g., temperature, spin-rates, concentration, etc.). This well-controlled and near-optimal BHJ morphology produced over a dozen cases of efficient OSCs with an active layer nearly 300 nm thick that can still achieve high FFs (70-77%) and efficiencies (10-11.7%). By studying the structure-property relationships of the donor polymers, we show that the second position branched alkyl chains and the fluorination on the polymer backbone are two key structural features that enable the strong TDA property. Our comparative studies also show that the TDA polymer family can be used to match with non-fullerene acceptors yielding OSCs with low voltage losses. The key difference between the empirical matching rules for fullerene and non-fullerene OSCs is that TDA polymers with slightly reduced crystallinity appear to match better with small molecular acceptors and yield higher OSC performances.

Effect of Nb on microstructure and yield strength of a high temperature tempered martensitic steel

NASA Astrophysics Data System (ADS)

Wang, Qian; Sun, Yu; Zhang, Chuanyou; Wang, Qingfeng; Zhang, Fucheng

2018-04-01

Martensitic steels based on a composition of 25CrMo47NbVTi with different concentrations of Nb (0.003%–0.060%) were quenched (Q) at 900 °C and tempered (T) at 700 °C to obtain oil country tubular goods (OCTG) with higher yield strength. The precipitation and microstructures were characterized and quantified by optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction (XRD). The results show that the increased Nb content led to an enhanced overall precipitation, the rising solution-precipitation temperature, the increased mass or volume fraction of the Nb-containing precipitates, and the decreased average diameter of Nb-containing particles. With the enhanced precipitation of small sized Nb-containing particles, the austenite grain and corresponding martensitic packet and block were evidently refined. In addition, the dislocation density increased slightly with increasing Nb addition. The yield strength was experimentally measured and quantitatively estimated. The findings based on theoretical calculations indicated that as a consequence of intensified strengthening from grain boundaries, precipitates and dislocations, the yield strength was enhanced significantly by Nb addition.

Enhancement of low-temperature thermometry by strong coupling

NASA Astrophysics Data System (ADS)

Correa, Luis A.; Perarnau-Llobet, Martí; Hovhannisyan, Karen V.; Hernández-Santana, Senaida; Mehboudi, Mohammad; Sanpera, Anna

2017-12-01

We consider the problem of estimating the temperature T of a very cold equilibrium sample. The temperature estimates are drawn from measurements performed on a quantum Brownian probe strongly coupled to it. We model this scenario by resorting to the canonical Caldeira-Leggett Hamiltonian and find analytically the exact stationary state of the probe for arbitrary coupling strength. In general, the probe does not reach thermal equilibrium with the sample, due to their nonperturbative interaction. We argue that this is advantageous for low-temperature thermometry, as we show in our model that (i) the thermometric precision at low T can be significantly enhanced by strengthening the probe-sampling coupling, (ii) the variance of a suitable quadrature of our Brownian thermometer can yield temperature estimates with nearly minimal statistical uncertainty, and (iii) the spectral density of the probe-sample coupling may be engineered to further improve thermometric performance. These observations may find applications in practical nanoscale thermometry at low temperatures—a regime which is particularly relevant to quantum technologies.

Biochemical properties and yields of diverse bacterial laccase-like multicopper oxidases expressed in Escherichia coli

PubMed Central

Ihssen, Julian; Reiss, Renate; Luchsinger, Ronny; Thöny-Meyer, Linda; Richter, Michael

2015-01-01

Laccases are multi-copper oxidases that oxidize a broad range of substrates at the expense of molecular oxygen, without any need for co-factor regeneration. These enzymes bear high potential for the sustainable synthesis of fine chemicals and the modification of (bio)polymers. Here we describe cloning and expression of five novel bacterial laccase-like multi copper oxidases (LMCOs) of diverse origin which were identified by homology searches in online databases. Activity yields under different expression conditions and temperature stabilities were compared to three previously described enzymes from Bacillus subtilis, Bacillus pumilus and Bacillus clausii. In almost all cases, a switch to oxygen-limited growth conditions after induction increased volumetric activity considerably. For proteins with predicted signal peptides for secretion, recombinant expression with and without signal sequence was investigated. Bacillus CotA-type LMCOs outperformed enzymes from Streptomyces and Gram-negative bacteria with respect to activity yields in Escherichia coli and application relevant biochemical properties. The novel Bacillus coagulans LMCO combined high activity yields in E. coli with unprecedented activity at strong alkaline pH and high storage stability, making it a promising candidate for further development. PMID:26068013

Simultaneous improvement of grain yield and protein content in durum wheat by different phenotypic indices and genomic selection.

PubMed

Rapp, M; Lein, V; Lacoudre, F; Lafferty, J; Müller, E; Vida, G; Bozhanova, V; Ibraliu, A; Thorwarth, P; Piepho, H P; Leiser, W L; Würschum, T; Longin, C F H

2018-06-01

Simultaneous improvement of protein content and grain yield by index selection is possible but its efficiency largely depends on the weighting of the single traits. The genetic architecture of these indices is similar to that of the primary traits. Grain yield and protein content are of major importance in durum wheat breeding, but their negative correlation has hampered their simultaneous improvement. To account for this in wheat breeding, the grain protein deviation (GPD) and the protein yield were proposed as targets for selection. The aim of this work was to investigate the potential of different indices to simultaneously improve grain yield and protein content in durum wheat and to evaluate their genetic architecture towards genomics-assisted breeding. To this end, we investigated two different durum wheat panels comprising 159 and 189 genotypes, which were tested in multiple field locations across Europe and genotyped by a genotyping-by-sequencing approach. The phenotypic analyses revealed significant genetic variances for all traits and heritabilities of the phenotypic indices that were in a similar range as those of grain yield and protein content. The GPD showed a high and positive correlation with protein content, whereas protein yield was highly and positively correlated with grain yield. Thus, selecting for a high GPD would mainly increase the protein content whereas a selection based on protein yield would mainly improve grain yield, but a combination of both indices allows to balance this selection. The genome-wide association mapping revealed a complex genetic architecture for all traits with most QTL having small effects and being detected only in one germplasm set, thus limiting the potential of marker-assisted selection for trait improvement. By contrast, genome-wide prediction appeared promising but its performance strongly depends on the relatedness between training and prediction sets.

Photoionization of the hydrogen atom in strong magnetic fields

NASA Technical Reports Server (NTRS)

Potekhin, Aleksandr IU.; Pavlov, George G.

1993-01-01

The photoionization of the hydrogen atom in magnetic fields B about 10 exp 11 - 10 exp 13 G typical of the surface layers of neutron stars is investigated analytically and numerically. We consider the photoionization from various tightly bound and hydrogen-like states of the atom for photons with arbitrary polarizations and wave-vector directions. It is shown that the length form of the interaction matrix elements is more appropriate in the adiabatic approximation than the velocity form, at least in the most important frequency range omega much less than omega(B), where omega(B) is the electron cyclotron frequency. Use of the length form yields nonzero cross sections for photon polarizations perpendicular to the magnetic field at omega less than omega(B); these cross sections are the ones that most strongly affect the properties of the radiation escaping from an optically thick medium, e.g., from the atmosphere of a neutron star. The results of the numerical calculations are fitted by simple analytical formulas.

Control of strong light-matter coupling using the capacitance of metamaterial nanocavities

DOE PAGES

Benz, Alexander; Campione, Salvatore; Klem, John Frederick; ...

2015-01-27

Metallic nanocavities with deep subwavelength mode volumes can lead to dramatic changes in the behavior of emitters placed in their vicinity. The resulting collocation and interaction often leads to strong coupling. We present for the first time experimental evidence that the Rabi splitting is directly proportional to the electrostatic capacitance associated with the metallic nanocavity. As a result, the system analyzed consists of different metamaterial geometries with the same resonance wavelength coupled to intersubband transitions in quantum wells.

Long-Term Monitoring of Rainfed Wheat Yield and Soil Water at the Loess Plateau Reveals Low Water Use Efficiency

PubMed Central

Qin, Wei; Chi, Baoliang; Oenema, Oene

2013-01-01

Increasing crop yield and water use efficiency (WUE) in dryland farming requires a quantitative understanding of relationships between crop yield and the water balance over many years. Here, we report on a long-term dryland monitoring site at the Loess Plateau, Shanxi, China, where winter wheat was grown for 30 consecutive years and soil water content (0–200 cm) was measured every 10 days. The monitoring data were used to calibrate the AquaCrop model and then to analyse the components of the water balance. There was a strong positive relationship between total available water and mean cereal yield. However, only one-third of the available water was actually used by the winter wheat for crop transpiration. The remaining two-thirds were lost by soil evaporation, of which 40 and 60% was lost during the growing and fallow seasons, respectively. Wheat yields ranged from 0.6 to 3.9 ton/ha and WUE from 0.3 to 0.9 kg/m3. Results of model experiments suggest that minimizing soil evaporation via straw mulch or plastic film covers could potentially double wheat yields and WUE. We conclude that the relatively low wheat yields and low WUE were mainly related to (i) limited rainfall, (ii) low soil water storage during fallow season due to large soil evaporation, and (iii) poor synchronisation of the wheat growing season to the rain season. The model experiments suggest significant potential for increased yields and WUE. PMID:24302987

Do clinicians want recommendations? A multi-center study comparing evidence summaries with and without GRADE recommendations.

PubMed

Neumann, Ignacio; Alonso-Coello, Pablo; Vandvik, Per Olav; Agoritsas, Thomas; Mas, Gemma; Akl, Elie A; Brignardello-Petersen, Romina; Emparanza, Jose; McCullagh, Lauren; De Sitio, Catherine; McGinn, Thomas; Almodaimegh, Hind; Almodaimegh, Khalid; Rivera, Solange; Rojas, Luis; Stirnemann, Jérôme; Irani, Jihad; Hlais, Sani; Mustafa, Reem; Bdair, Fadi; Aly, Abdelrahman; Kristiansen, Annette; Izcovich, Ariel; Ramirez, Anggie; Brozek, Jan; Guyatt, Gordon; Schünemann, Holger J

2018-03-09

Evidence-based clinical practice guidelines provide recommendations to assist clinicians in decision-making and to reduce the gap between best current research evidence and clinical practice. However, some argue that providing pre-appraised evidence summaries alone, rather than recommendations, is more appropriate. To evaluate clinicians' preferences, understanding of the evidence and intended course of action in response to evidence summaries with and without recommendations. We included practicing clinicians attending educational sessions across 10 countries. Clinicians were randomized to receive relevant clinical scenarios supported by research evidence of low or very-low certainty, and accompanied by either strong or weak recommendations developed with the GRADE system. Within each group, participants were further randomized to receive the recommendation plus the corresponding evidence summary or the evidence summary alone. We evaluated participants' preferences and understanding for the presentation strategy as well as their intended course of action. 189/219 (86%) and 201/248 (81%) participants preferred having recommendations accompanying evidence summaries for both strong and weak recommendations, respectively. Across all scenarios less than half of participants correctly interpreted information provided in the evidences summaries (e.g. estimates of effect, certainty in the research evidence). Presence of a recommendation resulted in a more appropriate intended course of action for two scenarios involving strong recommendations. Evidence summaries alone are not enough to impact clinicians' course of action. Clinicians clearly prefer having recommendations accompanying evidence summaries in the context of low or very-low certainty of evidence (Trial registration NCT02006017). Copyright © 2018 Elsevier Inc. All rights reserved.

Automatic semantic encoding in verbal short-term memory: evidence from the concreteness effect.

PubMed

Campoy, Guillermo; Castellà, Judit; Provencio, Violeta; Hitch, Graham J; Baddeley, Alan D

2015-01-01

The concreteness effect in verbal short-term memory (STM) tasks is assumed to be a consequence of semantic encoding in STM, with immediate recall of concrete words benefiting from richer semantic representations. We used the concreteness effect to test the hypothesis that semantic encoding in standard verbal STM tasks is a consequence of controlled, attention-demanding mechanisms of strategic semantic retrieval and encoding. Experiment 1 analysed the effect of presentation rate, with slow presentations being assumed to benefit strategic, time-dependent semantic encoding. Experiments 2 and 3 provided a more direct test of the strategic hypothesis by introducing three different concurrent attention-demanding tasks. Although Experiment 1 showed a larger concreteness effect with slow presentations, the following two experiments yielded strong evidence against the strategic hypothesis. Limiting available attention resources by concurrent tasks reduced global memory performance, but the concreteness effect was equivalent to that found in control conditions. We conclude that semantic effects in STM result from automatic semantic encoding and provide tentative explanations for the interaction between the concreteness effect and the presentation rate.

No grammatical gender effect on affective ratings: evidence from Italian and German languages.

PubMed

Montefinese, Maria; Ambrosini, Ettore; Roivainen, Eka

2018-06-06

In this study, we tested the linguistic relativity hypothesis by studying the effect of grammatical gender (feminine vs. masculine) on affective judgments of conceptual representation in Italian and German. In particular, we examined the within- and cross-language grammatical gender effect and its interaction with participants' demographic characteristics (such as, the raters' age and sex) on semantic differential scales (affective ratings of valence, arousal and dominance) in Italian and German speakers. We selected the stimuli and the relative affective measures from Italian and German adaptations of the ANEW (Affective Norms for English Words). Bayesian and frequentist analyses yielded evidence for the absence of within- and cross-languages effects of grammatical gender and sex- and age-dependent interactions. These results suggest that grammatical gender does not affect judgments of affective features of semantic representation in Italian and German speakers, since an overt coding of word grammar is not required. Although further research is recommended to refine the impact of the grammatical gender on properties of semantic representation, these results have implications for any strong view of the linguistic relativity hypothesis.

Genotype × environment interaction analysis of North American shrub willow yield trials confirms superior performance of triploid hybrids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fabio, Eric S.; Volk, Timothy A.; Miller, Raymond O.

Development of dedicated bioenergy crop production systems will require accurate yield estimates, which will be important for determining many of the associated environmental and economic impacts of their production. Shrub willow (Salix spp) is being promoted in areas of the USA and Canada due to its adaption to cool climates and wide genetic diversity available for breeding improvement. Willow breeding in North America is in an early stage, and selection of elite genotypes for commercialization will require testing across broad geographic regions to gain an understanding of how shrub willow interacts with the environment. We analyzed a dataset of first-rotationmore » shrub willow yields of 16 genotypes across 10 trial environments in the USA and Canada for genotype-by-environment interactions using the additive main effects and multiplicative interactions (AMMI) model. Mean genotype yields ranged from 5.22 to 8.58 oven-dry Mg ha -1 yr -1. Analysis of the main effect of genotype showed that one round of breeding improved yields by as much as 20% over check cultivars and that triploid hybrids, most notably Salix viminalis × S. miyabeana, exhibited superior yields. We also found important variability in genotypic response to environments, which suggests specific adaptability could be exploited among 16 genotypes for yield gains. Strong positive correlations were found between environment main effects and AMMI parameters and growing environment temperatures. These findings demonstrate yield improvements are possible in one generation and will be important for developing cultivar recommendations and for future breeding efforts.« less